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1.
  • Sanli, Kemal, et al. (author)
  • Metagenomic Sequencing of Marine Periphyton: Taxonomic and Functional Insights into Biofilm Communities
  • 2015
  • In: Frontiers in Microbiology. - : Frontiers Media SA. - 1664-302X. ; 6:1192
  • Journal article (peer-reviewed)abstract
    • Periphyton communities are complex phototrophic, multispecies biofilms that develop on surfaces in aquatic environments. These communities harbor a large diversity of organisms comprising viruses, bacteria, algae, fungi, protozoans and metazoans. However, thus far the total biodiversity of periphyton has not been described. In this study, we use metagenomics to characterize periphyton communities from the marine environment of the Swedish west coast. Although we found approximately ten times more eukaryotic rRNA marker gene sequences compared to prokaryotic, the whole metagenome-based similarity searches showed that bacteria constitute the most abundant phyla in these biofilms. We show that marine periphyton encompass a range of heterotrophic and phototrophic organisms. Heterotrophic bacteria, including the majority of proteobacterial clades and Bacteroidetes, and eukaryotic macro-invertebrates were found to dominate periphyton. The phototrophic groups comprise Cyanobacteria and the alpha-proteobacterial genus Roseobacter, followed by different micro- and macro-algae. We also assess the metabolic pathways that predispose these communities to an attached lifestyle. Functional indicators of the biofilm form of life in periphyton involve genes coding for enzymes that catalyze the production and degradation of extracellular polymeric substances, mainly in the form of complex sugars such as starch and glycogen-like meshes together with chitin. Genes for 278 different transporter proteins were detected in the metagenome, constituting the most abundant protein complexes. Finally, genes encoding enzymes that participate in anaerobic pathways, such as denitrification and methanogenesis, were detected suggesting the presence of anaerobic or low-oxygen micro-zones within the biofilms.
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2.
  • Shu, Nanjiang, 1981- (author)
  • Prediction of zinc-binding sites in proteins and efficient protein structure description and comparison
  • 2008
  • Licentiate thesis (other academic/artistic)abstract
    • A large number of proteins require certain metals to stabilize their structures or to function properly. About one third of all proteins in the Protein Data Bank (PDB) contain metals and it is estimated that approximately the same proportion of all proteins are metalloproteins. Zinc, the second most abundant transition metal found in eukaryotic organisms, plays key roles, mainly structural and catalytic, in many biological functions. Predicting whether a protein binds zinc and even the accurate location of binding sites is important when investigating the function of an experimentally uncharacterized protein. Describing and comparing protein structures with both efficiency and accuracy are essential for systematic annotation of functional properties of proteins, be it on an individual or on a genome scale. Dozens of structure comparison methods have been developed in the past decades. In recent years, several research groups have endeavoured in developing methods for fast comparison of protein structures by representing the three-dimensional (3D) protein structures as one-dimensional (1D) geometrical strings based on the shape symbols of clustered regions of φ/ψ torsion angle pairs of the polypeptide backbones. These 1D geometrical strings, shape strings, are as compact as 1D secondary structures but carry more elaborate structural information in loop regions and thus are more suitable for fast structure database searching, classification of loop regions and evaluation of model structures. In this thesis, a new method for predicting zinc-binding sites in proteins from amino acid sequences is described. This method predicts zinc-binding Cys, His, Asp and Glu (the four most common zinc-binding residues) with 75% precision (86% for Cys and His only) at 50% recall according to a solid 5-fold cross-validation on a non-redundant set of the PDB chains containing 2727 unique chains, of which 235 bind to zinc. This method predicts zinc-binding Cys and His with about 10% higher precision at different recall levels compared to a previously published method. In addition, different methods for describing and comparing protein structures are reviewed. Some recently developed methods based on 1D geometrical representation of backbone structures are emphasized and analyzed in details.
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4.
  • Tedersoo, Leho, et al. (author)
  • Novel soil-inhabiting clades fill gaps in the fungal tree of life
  • 2017
  • In: Microbiome. - : Springer Science and Business Media LLC. - 2049-2618. ; 5
  • Journal article (peer-reviewed)abstract
    • Background - Fungi are a diverse eukaryotic group of degraders, pathogens, and symbionts, with many lineages known only from DNA sequences in soil, sediments, air, and water. Results - We provide rough phylogenetic placement and principal niche analysis for >40 previously unrecognized fungal groups at the order and class level from global soil samples based on combined 18S (nSSU) and 28S (nLSU) rRNA gene sequences. Especially, Rozellomycota (Cryptomycota), Zygomycota s.lat, Ascomycota, and Basidiomycota are rich in novel fungal lineages, most of which exhibit distinct preferences for climate and soil pH. Conclusions - This study uncovers the great phylogenetic richness of previously unrecognized order- to phylum-level fungal lineages. Most of these rare groups are distributed in different ecosystems of the world but exhibit distinct ecological preferences for climate or soil pH. Across the fungal kingdom, tropical and non-tropical habitats are equally likely to harbor novel groups. We advocate that a combination of traditional and high-throughput sequencing methods enable efficient recovery and phylogenetic placement of such unknown taxonomic groups.
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5.
  • Hennerdal, Aron, et al. (author)
  • Internal duplications in alpha-helical membrane protein topologies are common but the nonduplicated forms are rare
  • 2010
  • In: Protein Science. - : Wiley. - 0961-8368 .- 1469-896X. ; 19:12, s. 2305-2318
  • Journal article (peer-reviewed)abstract
    • Many alpha-helical membrane proteins contain internal symmetries, indicating that they might have evolved through a gene duplication and fusion event Here, we have characterized internal duplications among membrane proteins of known structure and in three complete genomes We found that the majority of large transmembrane (TM) proteins contain an internal duplication The duplications found showed a large variability both in the number of TM-segments included and in their orientation Surprisingly, an approximately equal number of antiparallel duplications and parallel duplications were found However, of all 11 superfamilies with an internal duplication, only for one, the AcrB Multidrug Efflux Pump, the duplicated unit could be found in its nonduplicated form An evolutionary analysis of the AcrB homologs indicates that several independent fusions have occurred, including the fusion of the SecD and SecF proteins into the 12-TM-protein SecDF in Brucella and Staphylococcus aureus In one additional case, the Vitamin B-12 transporter-like ABC transporters, the protein had undergone an additional fusion to form protein with 20 TM-helices in several bacterial genomes Finally, homologs to all human membrane proteins were used to detect the presence of duplicated and nonduplicated proteins This confirmed that only in rare cases can homologs with different duplication status be found, although internal symmetry is frequent among these proteins One possible explanation is that it is frequent that duplication and fusion events happen simultaneously and that there is almost always a strong selective advantage for the fused form
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6.
  • Buckland, Philip I., 1973-, et al. (author)
  • The Strategic Environmental Archaeology Database : a resource for international, multiproxy and transdisciplinary studies of environmental and climatic change
  • 2015
  • Conference paper (peer-reviewed)abstract
    • Climate and environmental change are global challenges which require global data and infrastructure to investigate. These challenges also require a multi-proxy approach, integrating evidence from Quaternary science and archaeology with information from studies on modern ecology and physical processes among other disciplines. The Strategic Environmental Archaeology Database (SEAD http://www.sead.se) is a Swedish based international research e-infrastructure for storing, managing, analysing and disseminating palaeoenvironmental data from an almost unlimited number of analysis methods. The system currently makes available raw data from over 1500 sites (>5300 datasets) and the analysis of Quaternary fossil insects, plant macrofossils, pollen, geochemistry and sediment physical properties, dendrochronology and wood anatomy, ceramic geochemistry and bones, along with numerous dating methods. This capacity will be expanded in the near future to include isotopes, multi-spectral and archaeo-metalurgical data. SEAD also includes expandable climate and environment calibration datasets, a complete bibliography and extensive metadata and services for linking these data to other resources. All data is available as Open Access through http://qsead.sead.se and downloadable software. SEAD is maintained and managed at the Environmental Archaeology Lab and HUMlab at Umea University, Sweden. Development and data ingestion is progressing in cooperation with The Laboratory for Ceramic Research and the National Laboratory for Wood Anatomy and Dendrochronology at Lund University, Sweden, the Archaeological Research Laboratory, Stockholm University, the Geoarchaeological Laboratory, Swedish National Historical Museums Agency and several international partners and research projects. Current plans include expanding its capacity to serve as a data source for any system and integration with the Swedish National Heritage Board's information systems. SEAD is partnered with the Neotoma palaeoecology database (http://www.neotomadb.org) and a new initiative for building cyberinfrastructure for transdisciplinary research and visualization of the long-term human ecodynamics of the North Atlantic funded by the National Science Foundation (NSF).
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7.
  • Alm Rosenblad, Magnus, 1957, et al. (author)
  • Detection of signal recognition particle (SRP) RNAs in the nuclear ribosomal internal transcribed spacer 1 (ITS1) of three lineages of ectomycorrhizal fungi (Agaricomycetes, Basidiomycota)
  • 2016
  • In: MycoKeys. - : Pensoft Publishers. - 1314-4057 .- 1314-4049. ; 13, s. 21-33
  • Journal article (peer-reviewed)abstract
    • During a routine scan for Signal Recognition Particle (SRP) RNAs in eukaryotic sequences, we surprisingly found in silico evidence in GenBank for a 265-base long SRP RNA sequence in the ITS1 region of a total of 11 fully identified species in three ectomycorrhizal genera of the Basidiomycota (Fungi): Astraeus, Russula, and Lactarius. To rule out sequence artifacts, one specimen from a species indicated to have the SRP RNA-containing ITS region in each of these genera was ordered and re-sequenced. Sequences identical to the corresponding GenBank entries were recovered, or in the case of a non-original but conspecific specimen differed by three bases, showing that these species indeed have an SRP RNA sequence incorporated into their ITS1 region. Other than the ribosomal genes, this is the first known case of non-coding RNAs in the eukaryotic ITS region, and it may assist in the examination of other types of insertions in fungal genomes.
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8.
  • Mishra, Laxmi S., 1983- (author)
  • FtsH metalloproteases and their pseudo-proteases in the chloroplast envelope of Arabidopsis thaliana
  • 2021
  • Doctoral thesis (other academic/artistic)abstract
    • By cleaving peptide bonds, proteases either activate or degrade proteins and maintain protein quality control in response to various developmental stimuli and environmental factors. My work has focused on elucidating the role of the filamentation temperature sensitive protein H (FtsH) proteases. FtsHs belong to a membrane-embedded class of proteases found in eubacteria, animals and plants, which are located in the organelles of endosymbiosis (mitochondria and chloroplasts). They possess an AAA+ (ATPase associated with various cellular activities) and a peptidase M41 domain containing the HEXXH consensus sequence in the Zn2+ metalloprotease domain. FtsH proteases are known to form ring-like homo- or hetero-hexameric complexes. Arabidopsis thaliana, the model plant used in this study, contains seventeen AtFtsH proteases, of which twelve are presumably proteolytically active and five presumably proteolytic inactive members, known as AtFtsHi (i for inactive). In AtFtsHi members, the HEXXH motif is either deleted (AtFtsHi3) or mutated (AtFtsHi1, 2, 4, 5). Twelve AtFtsHs (AtFtsH 1, 2, 5–9, 11, 12 and AtFtsHi 1-5) are targeted to the chloroplast, whereas the remaining three (AtFtsH 3, 4 and 10) are mitochondrial. In Paper I, we demonstrate that AtFtsH12 interacts with AtFtsHi1, 2, 4, 5 to form a heteromeric complex. Abundance of these AtFtsH12-AtFtsHi complexes alters the accumulation of TIC (translocon on the inner chloroplast membrane) complexes. Transgenic mi12 (miRNA) knockdown plants that express lower amounts of AtFtsH12 displayed a pale-seedling and an aberrant chloroplast phenotype. mi12 plants displayed lowered total chlorophyll (Chla+Chlb) amount compared to wild type (WT), complementation lines and native AtFtsH12 promoter overexpressor (ox12) lines. Our biochemical studies identified drastic modifications in the total proteome of mi12 seedlings. N-terminome analyses of mi12 seedlings showed undisturbed plastidic protein maturation. In Paper II, we have shown that single mutants depleted in AtFTSHI1, 2, 4 or 5 are embryo-lethal, suggesting the pseudo-proteases to have an indispensable role in seed germination. This study further identified “weak” Atftshi1, Atftshi4, Atftshi3-1(kd) and Atftshi3-2 homozygous mutants, which develop into plants with altered photosynthetic efficiency. Field experiments were performed to determine the Darwinian fitness of these homozygous as well as heterozygous AtFtsHi mutants. The results suggested AtFtsHi enzymes to be critical during early developmental stages. A complete Atftshi3 knockdown mutant (Atftshi3-1(kd)) was identified (described in Paper III), which is not embryo-lethal and tolerates drought better than WT plants. Atftshi3-1(kd) leaves were smaller with fewer and smaller stomatal aperture. Above ground, Atftshi3-1(kd) leaves displayed lowered stomatal conductance and increased WUEi (intrinsic water-use efficiency), while below ground, the root-associated bacterial community showed a typical drought stress response. Upregulated transcripts of the ABA-responsive genes in leaves of Atftshi3-1(kd) compared to WT indicate the drought tolerance to be controlled independently of ABA. To conclude, AtFtsHi pseudo-proteases affect various stages of plant development and abiotic stress management, especially drought.
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9.
  • Sigvald, Roland, et al. (author)
  • Molecular identification of bloodmeals and species composition in Culicoides biting midges
  • 2013
  • In: Medical and Veterinary Entomology. - : Wiley. - 0269-283X .- 1365-2915. ; 27, s. 104-112
  • Journal article (peer-reviewed)abstract
    • Investigations of host preferences in haematophagous insects, including Culicoides biting midges (Diptera: Ceratopogonidae), are critical in order to assess transmission routes of vector-borne diseases. In this study, we collected and morphologically identified 164 blood-engorged Culicoides females caught in both light traps and permanent 12-m high suction traps during 20082010 in Sweden. Molecular analysis of the mitochondrial cytochrome c oxidase subunit I (COI) gene in the biting midges was performed to verify species classification, discern phylogenetic relationships and uncover possible cryptic species. Bloodmeal analysis using universal vertebrate cytochrome b primers revealed a clear distinction in host selection between mammalophilic and ornithophilic Culicoides species. Host sequences found matches in horse (n = 59), sheep (n = 39), cattle (n = 26), Eurasian elk (n = 1) and 10 different bird species (n = 18). We identified 15 Culicoides species previously recorded in Scandinavia and four additional species haplotypes that were distinctly different from the described species. All ornithophilic individuals (n = 23) were caught exclusively in the suction traps, as were, interestingly, almost all mammalophilic species (n = 41), indicating that many biting midge species may be able to cover long distances after completing a bloodmeal. These results add new information on the composition of Culicoides species and their host preferences and their potential long-distance dispersal while blood-engorged.
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10.
  • Ihse, Elisabet, 1977-, et al. (author)
  • Amyloid fibrils with fragmented ATTR may be the rule in non-Val30Met ATTR amyloidosis
  • Other publication (other academic/artistic)abstract
    • The clinical phenotype of familial ATTR amyloidosis depends to some extent on the particular mutation, but differences exist also within mutations. We have previously described that two types of amyloid fibril compositions exist among Swedish ATTRV30M amyloidosis patients, one consisting of a mixture of intact and fragmented ATTR (type A) and one composed of only intact ATTR (type B). Patients with type A fibrils have a late age of onset and signs of cardiomyopathy, while patients with type B fibrils have an early onset and much less myocardial involvement. The present study aimed to determine if the correlation between fibril type and clinical phenotype is true for familial amyloidosis in general. Cardiac and/or adipose tissue from 48 patients carrying 21 different non-TTRV30M mutations were examined, as well as 7 non-Swedish ATTRV30M patients. Fibril type was determined with western blotting and compared to the patients´ age of onset and degree of cardiomyopathy. Non-Swedish V30M patients showed the same correlation as described for Swedish V30M patients, with fibrils of only full-length ATTR (type B) linked to less myocardial involvement. In contrast, all patients with non-V30M mutations had a fibril composition with ATTR fragments (type A). Some of these patients had onset of disease at young age. The vast majority had increased thickness of left cardiac ventricle, but a few individuals had values within normal limits. This study shows that a fibril composition with fragmented ATTR is very common in ATTR amyloidosis. It also suggests that fibrils composed of only full-length ATTR is an exception, perhaps only found among young ATTRV30M amyloidosis patients.
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11.
  • Ihse, Elisabet, 1977- (author)
  • Two Types of Fibrils in ATTR Amyloidosis : Implications for Clinical Phenotype and Treatment Outcome
  • 2011
  • Doctoral thesis (other academic/artistic)abstract
    • Systemic amyloidoses are a group of lethal diseases where proteins aggregate into fibrillar structures, called amyloid fibrils, that deposits throughout the body. Transthyretin (TTR) causes one type of amyloidosis, in which the aggregates mainly infiltrate nervous and cardiac tissue. Almost a hundred different mutations in the TTR gene are known to trigger the disease, but wild-type (wt) TTR is also incorporated into the fibrils, and may alone form amyloid. Patients with the TTRV30M mutation show, for unknown reasons, two clinical phenotypes. Some have an early onset of disease without cardiomyopathy while others have a late onset and cardiomyopathy. It has previously been described that amyloid fibrils formed from TTRV30M can have two different compositions; either with truncated molecules beside full-length TTR (type A) or only-full-length molecules (type B).  In this thesis, the clinical importance of the two types of amyloid fibrils was investigated. We found that the fibril composition types are correlated to the two clinical phenotypes seen among TTRV30M patients, with type A fibrils present in late onset patients and type B fibrils in early onset patients. The only treatment for hereditary TTR amyloidosis has been liver transplantation, whereby the liver producing the mutant TTR is replaced by an organ only producing wt protein. However, in some patients, cardiac symptoms progress post-transplantationally. We demonstrated that the propensity to incorporate wtTTR differs between fibril types and tissue types in TTRV30M patients, with cardiac amyloid of type A having the highest tendency. This offers an explanation to why particularly cardiac amyloidosis develops after transplantation, and suggests which patients that are at risk for such development. By examining patients with other mutations than TTRV30M, we showed that, in contrast to the general belief, a fibril composition with truncated TTR is very common and might even be the general rule. This may explain why TTRV30M patients often have a better outcome after liver transplantation than patients with other mutations. In conclusion, this thesis has contributed with one piece to the puzzle of understanding the differences in clinical phenotype and treatment response between TTR amyloidosis patients, by demonstrating corresponding differences at a molecular level.
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12.
  • Alfredsson Timmins, Jenny, 1976- (author)
  • Functional organisation of the cell nucleus in the fission yeast, Schizosaccharomyces pombe
  • 2009
  • Doctoral thesis (other academic/artistic)abstract
    • In eukaryotes the genome adopts a non-random spatial organisation, which is important for gene regulation. However, very little is known about the driving forces behind nuclear organisation. In the simple model eukaryote fission yeast, Schizosaccharomyces pombe, it has been known for a long time that transcriptionally repressed heterochromatin localise to the nuclear membrane (NM); the centromeres attaches to spindle pole body (SPB), while the telomeres are positioned at the NM on the opposite side of the nucleus compared to the SPB. Studies presented in this thesis aimed at advancing our knowledge of nuclear organisation in Schizosaccharomyces pombe. We show that the heterochromatic mating-type region localises to the NM in the vicinity of the SPB. This positioning was completely dependent on Clr4, a histone methyl transferase crucial for the formation of heterochromatin. Additional factors important for localisation were also identified: the chromo domain protein Swi6, and the two boundary elements IR-L and IR-R surrounding this locus. We further identify two other chromo domain proteins; Chp1 and Chp2, as crucial factors for correct subnuclear localisation of this region. From these results we suggest that the boundary elements together with chromodomain proteins in balanced dosage and composition cooperate in organising the mating-type chromatin. Gene regulation can affect the subnuclear localisation of genes. Using nitrogen starvation in S. pombe as a model for gene induction we determined the subnuclear localisation of two gene clusters repressed by nitrogen: Chr1 and Tel1. When repressed these loci localise to the NM, and this positioning is dependent on the histone deacetylase Clr3. During induction the gene clusters moved towards the nuclear interior in a transcription dependent manner. The knowledge gained from work presented in this thesis, regarding nuclear organisation in the S. pombe model system, can hopefully aid to a better understanding of human nuclear organisation.
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13.
  • Bag, Pushan, 1993- (author)
  • How could Christmas trees remain evergreen? : photosynthetic acclimation of Scots pine and Norway spruce needles during winter
  • 2022
  • Doctoral thesis (other academic/artistic)abstract
    • Plants and other green organisms harvest sunlight by green chlorophyll pigments and covertit to chemical energy (sugars) and oxygen in a process called photosynthesis providing the foundation for life on Earth. Although it is unanimously believed that oceanic phytoplanktons are the main contributors to the global photosynthesis, the contribution of coniferous boreal forests distributed across vast regions of the northern hemisphere cannot be undermined. Hence boreal forests account signifificantly for social, economical and environmental sustainability. Not only do conifers thrive in the tundra regions with extreme climate, but they also maintain their needles green over the boreal winter. A question remains; what makes them so resilient? In this respect, we aimed to understand the remarkable winter adaptation strategies in two dominant boreal coniferous species,i.e., Pinus sylvestris and Picea abies. First, we mapped the transcriptional landscape in Norway spruce (Picea abies) needles over the annual cycle. Transcriptional changes in the nascent needles reflflected a sequence of developmental processes and active vegetative growth during early summer and summer. Later after maturation, transcriptome reflflected activated defense against biotic factors and acclimationin response to abiotic environmental cues such as freezing temperatures during winter. Secondly, by monitoring the photosynthetic performance of Scot pine needles, we found that the trees face extreme stress during the early spring (Feb-Mar) when sub-zero temperatures are accompanied by high solar radiation. At this time, drastic changes occur in the thylakoid membranes of the chloroplast that allows the mixing of photosystem I and photosystem II that typically remain laterally segregated. This triggers direct energy transfer from PSII to PSI and thus protects PSII from damage. Furthermore, we found that this loss of lateral segregation may be a consequence of triple phosphorylationof Lhcb1 (Light harvesting complex1 of photosystem II). The structural changes in thylakoid membranes also lead to changes inthe thylakoid macro domain organisationand pigment protein composition. Furthermore, we discovered that while PSII is protected by direct energy transfer, the protection of PSI is provided through photoreduction of oxygen by flavodiiron proteins, which in turn allows P700 to stay in an oxidised state necessary for direct energy transfer. These coordinated cascades of changes concomitantly protect both PSI and PSII to maintain the needles green over the winter.
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14.
  • Cheung, Henry Lok Shan, et al. (author)
  • Denitrification, anammox, and DNRA in oligotrophic continental shelf sediments
  • 2024
  • In: Limnology and Oceanography. - 1939-5590 .- 0024-3590.
  • Journal article (peer-reviewed)abstract
    • Continental shelf sediments are considered hotspots for nitrogen (N) removal. While most investigations have quantified denitrification in shelves receiving large amounts of anthropogenic nutrient supply, we lack insight into the key drivers of N removal on oligotrophic shelves. Here, we measured rates of N removal through denitrification and anammox by the revised-isotope pairing technique (r-IPT) along the Northeastern New Zealand shelf. Denitrification dominated total N2 production at depths between 30 and 128 m with average rates (± SE) ranging from 65 ± 28 to 284 ± 72 μmol N m−2 d−1. N2 production by anammox ranged from 3 ± 1 to 28 ± 11 μmol N m−2 d−1 and accounted for 2–19% of total N2 production. DNRA was negligible in these oligotrophic settings. Parallel microbial community analysis showed that both Proteobacteria and Planctomycetota were key taxa driving denitrification. Denitrification displayed a negative correlation with oxygen penetration depth, and a positive correlation with macrofauna abundance. Our denitrification rates were comparable to oligotrophic shelves from the Arctic, but were lower than those from nutrient-rich Pacific and Atlantic shelves. Based on our results and existing IPT measurements, the global shelf denitrification rate was reassessed to be 53.5 ± 8.1 Tg N yr−1, equivalent to 20 ± 2% of marine N removal. We suggest that previous estimates of global shelf N loss might have been overestimated due to sampling bias toward areas with high N loads in the Northern Hemisphere.
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15.
  • Janzon, Anders, 1978, et al. (author)
  • Exploring the microbial resistome in river sediments exposed to extraordinary high levels of antibiotics
  • 2010
  • In: 35th FEBS Congress: Molecules of Life.
  • Conference paper (other academic/artistic)abstract
    • The rapid development and propagation of antibiotic resistance in pathogenic and opportunistic bacteria is a major threat to public health worldwide. The phenomenon has been widely studied in the clinical setting, but comparatively little is known about the prevalence and diversity of antibiotic resistance in communities of environmental bacteria, often referred to as the environmental resistome. As the external environment may function as a reservoir of resistance genes to human pathogens, we are interested in how environmental bacteria are affected by antibiotic pollution. We have previously isolated microbial DNA from river sediments taken up- and downstream from a water treatment plant that processes waste water from several pharmaceutical plants producing antibiotics. In a previous study, we used deep sequencing to identify unprecedented frequencies of known resistance genes to several classes of antibiotics in these samples. In this study, we aim to functionally characterize the resistome in a more open and exploratory way by screening genomic DNA libraries transformed into sensitive hosts. To generate the libraries, several experimental strategies were explored, including mechanical shearing and enzymatic digestion of the isolated DNA followed by blunt- or sticky end cloning into different plasmids, subsequently transformed into sensitive E. coli. Pros and cons of the different strategies will be discussed along with preliminary results of the screening against selected antibiotics.
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16.
  • Klevebring, Daniel, 1981- (author)
  • On Transcriptome Sequencing
  • 2009
  • Doctoral thesis (other academic/artistic)abstract
    • This thesis is about the use of massive DNA sequencing to investigate the transcriptome. During recent decades, several studies have made it clear that the transcriptome comprises a more complex set of biochemical machinery than was previously believed. The majority of the genome can be expressed as transcripts; and overlapping and antisense transcription is widespread. New technologies for the interroga- tion of nucleic acids have made it possible to investigate such cellular phenomena in much greater detail than ever before. For each application, special requirements need to be met. The work presented in this thesis focuses on the transcrip- tome and the development of technology for its analysis. In paper I, we report our development of an automated approach for sample preparation. The procedure was benchmarked against a publicly available reference data set, and we note that our approach outperformed similar manual procedures in terms of reproducibility. In the work reported in papers II-IV, we used different massive sequencing technologies to investigate the transcriptome. In paper II we describe a concatemerization approach that increased throughput by 65% using 454 sequencing,and we identify classes of transcripts not previously described in Populus. Papers III and IV both report studies based on SOLiD sequencing. In the former, we investigated transcripts and proteins for 13% of the human gene and detected a massive overlap for the upper 50% transcriptional levels. In the work described in paper IV, we investigated transcription in non-genic regions of the genome and detected expression from a high number of previ- ously unknown loci.
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18.
  • Wikström, P, et al. (author)
  • The regulatory N-terminal region of the aromatic-responsive transcriptional activator DmpR constrains nucleotide-triggered multimerisation.
  • 2001
  • In: Journal of Molecular Biology. - : Elsevier BV. - 0022-2836 .- 1089-8638. ; 314:5
  • Journal article (peer-reviewed)abstract
    • The transcriptional promoting activity of DmpR is under the strict control of its aromatic effector ligands that are bound by its regulatory N-terminal domain. The positive control function of DmpR resides within the central C-domain that is highly conserved among activators of sigma(54)-RNA polymerase. The C-domain mediates ATP hydrolysis and interaction with sigma(54)-RNA polymerase that are essential for open-complex formation and thus initiation of transcription. Wild-type and loss-of-function derivatives of DmpR, which are defective in distinct steps in nucleotide catalysis, were used to address the consequences of nucleotide binding and hydrolysis with respect to the multimeric state of DmpR and its ability to promote in vitro transcription. Here, we show that DmpR derivatives deleted of the regulatory N-terminal domain undergo an aromatic-effector independent ATP-binding triggered multimerisation as detected by cross-linking. In the intact protein, however, aromatic effector activation is required before ATP-binding can trigger an apparent dimer-to-hexamer switch in subunit conformation. The data suggest a model in which the N-terminal domain controls the transcriptional promoting property of DmpR by constraining ATP-mediated changes in its oligomeric state. The results are discussed in the light of recent mechanistic insights from the AAA(+) superfamily of ATPases that utilise nucleotide hydrolysis to restructure their substrates.
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20.
  • Mamontov, Eugen, 1955 (author)
  • Homeorhesis and evolutionary properties of living systems: From ordinary differential equations to the active-particle generalized kinetics theory
  • 2006
  • In: 10th Evolutionary Biology Meeting at Marseilles, 20-22 September 2006, Marseilles, France.
  • Conference paper (peer-reviewed)abstract
    • Advanced generalized-kinetic-theory (GKT) models for biological systems are developed for populations of active (or living) particles [1]-[5]. These particles are described with both the stochastic variables common in kinetic theory (such as time, the particle random location and velocity) and the stochastic variables related to the internal states of an active particle. Evolution of these states represents biological, ecological, or social properties of the particle behavior. Paper [6] analyzes a number of the well-known statistical-mechanics approaches and shows that the active-particle GKT (APGKT) is the only treatment capable of modelling living systems. Work [2] summarizes the significance of the notion of an active particle in kinetic models. This notion draws attention to the features distinguishing living matter from nonliving matter. They are discussed by many authors (e.g., [7]-[15], [1]-[3], [6], [16]-[18]). Work [11] considers a lot of differences between living and nonliving matters, and the limitations of the modelling approaches developed for nonliving matter. Work [6] mainly focuses on the comparison of a few theoretical mechanics treatments in terms of the key living-matter properties formulated in [15]. One of the necessary properties of the evolution of living systems is homeorhesis. It is, loosely speaking, a peculiar qualitative and quantitative insensitivity of a living system to the exogenous signals acting on it. The earlier notion, homeostasis, was introduced by W. B. Cannon in 1926 who discussed the phenomenon in detail later [7]. Homeorhesis introduced by C. H. Waddington [8, p. 32] generalizes homeostasis and is well known in biology [8], [9], [12]. It is an inherent part of mathematical models for oncogeny (e.g., [16]-[18], [6, Appendix]). Homeorhesis is also discussed in [3, Section 4] in connection with APGKT. Homeorhesis is documented in ecology (e.g., [11], [13, the left column on p. 675]) where it is one of the key notions of the strong Gaia theory, a version of the Gaia theory (e.g., [14, Chapter 8]). The strong Gaia theory “states that the planet with its life, a single living system, is regulated in certain aspects by that life” [14, p. 124]. The very origin of the name “Gaia” is related to homeorhesis or homeostasis [14, p. 118]. These notions are also used in psychology and sociology. If evolution of a system is not homeorhetic, the system can not be living. Work [6, Appendix] derives a preliminary mathematical formulation of homeorhesis in terms of the simplest dynamical systems, i.e. ordinary differential equations (ODEs). The present work complements, extended, and further specify the approach of [6, Appendix]. The work comprises the two main parts. The first part develops the sufficient conditions for ODE systems to describe homeorhesis, and suggests a fairly general structure of the ODE model. It regards homeorhesis as piecewise homeostasis. The model can be specified in different ways depending on specific systems and specific purposes of the analysis. An example of the specification is also noted (the PhasTraM nonlinear reaction-diffusion model for hyperplastic oncogeny [16]-[18]). The second part of the work discusses implementation of the above homeorhesis ODE model in terms of a special version [3] of APGKT (see above). The key feature of this version is that the components of a living population need not be discrete: the subdivision into the components is described with a general, continuous-discrete probability distribution (see also [6]). This enables certain properties of living matter noted in [15]. Moreover, the corresponding APGKT model presents a system of, firstly, a generalized kinetic equation for the conditional distribution function conditioned by the internal states of the population and, secondly, Ito's stochastic differential equations for these states. This treatement employs the results on nonstationary invariant diffusion stochastic processes [19]. The second part of the work also stresses that APGKT is substantially more important for the living-matter analysis than in the case of nonliving matter. One of the reasons is certain limitations in experimental sampling of the living-system modes presented with stochastic processes. A few directions for future research are suggested as well. REFERENCES: [1] Bellomo, N., Bellouquid, A. and Delitala, M., 2004, Mathematical topics on the modelling complex multicellular systems and tumor immune cells competition, Math. Models Methods Appl. Sci., 14, 1683-1733. [2] Bellomo, N., 2006, New hot Paper Comments, Essential Science Indicators, http://www.esi-topics.com/nhp/2006 /may- 06-NicolaBellomo.html. [3] Willander, M., Mamontov, E. and Chiragwandi, Z., 2004, Modelling living fluids with the subdivision into the components in terms of probability distributions, Math. Models Methods Appl. Sci. 14, 1495-1520. [4] Bellomo, N. and Maini, P.K., 2005, Preface and the Special Issue “Multiscale Cancer Modelling-A New Frontier in Applied Mathematics”, Math. Models Methods Appl. Sci., 15, iii-viii. [5] De Angelis, E. and Delitala, M., 2006, Modelling complex systems in applied sciences: Methods and tools of the mathematical kinetic theory for active particles. Mathl Comput. Modelling, 43, 1310-1328. [6] Mamontov, E., Psiuk-Maksymowicz, K. and Koptioug, A., 2006, Stochastic mechanics in the context of the properties of living systems, Mathl Comput. Modelling, Article in Press, 13 pp. [7] Cannon, W.B., 1932, The Wisdom of the Body (New York: Norton). [8] Waddington, C.H., 1957, The Strategy of the Genes. A Discussion of Some Aspects of Theoretical Biology (London, George Allen and Unwin). [9] Waddington, C.H., 1968, Towards a theoretical biology, Nature, 218, 525-527. [10] Cotnoir, P.-A., 1981, La compétence environnementale: Une affaire d’adaptation. Séminaire en écologie behaviorale, Univeristé du Québec, Montralé. Available online at: http://pac.cam.org/culture.doc . [11] O’Neill, R.V., DeAngelis, D.L., Waide, J.B. and Allen, T.F.H., 1986, A Hierarchical Concept of Ecosystems, Princeton: Princeton Univ. Press). [12] Sauvant, D., 1992, La modélisation systémique en nutrition, Reprod. Nutr. Dev., 32, 217-230. [13] Christensen, N.L., Bartuska, A.M., Brown, J.H., Carpenter, S., D'Antonio, C., Francis, R., Franklin, J.F., MacMahon, J.A., Noss, R.F., Parsons, D.J., Peterson, C.H., Turner, M.G. and Woodmansee, R.G., 1996, The Report of the Ecological Society of America Committee on the Scientific Basis for Ecosystem Management, Ecological Applications, 6, 665-691. Available online at: http://www.esa.org/pao/esaPositions/Papers/ReportOfSBEM.php. [14] Margulis, L., 1998, Symbiotic Planet. A New Look at Evolution (Amherst: Sciencewriters). [15] Hartwell, L.H., Hopfield, J.J., Leibler, S. and Murray, A.W., 1999, From molecular to modular cell biology, Nature, 402, C47-C52. [16] Mamontov, E., Koptioug, A.V. and Psiuk-Maksymowicz, K., 2006, The minimal, phase-transition model for the cell- number maintenance by the hyperplasia-extended homeorhesis, Acta Biotheoretica, 54, 44 pp., (no. 2, May-June, accepted). [17] Psiuk-Maksymowicz, K. and Mamontov, E., 2005, The time-slices method for rapid solving the Cauchy problem for nonlinear reaction-diffusion equations in the competition of homeorhesis with genotoxically activated hyperplasia, In: European Conference on Mathematical and Theoretical Biology - ECMTB05 (July 18-22, 2005) Book of Abstracts, Vol.1 (Dresden: Center for Information Services and High Performance Computing, Dresden Univ. Technol.), p. 429 (http://www.ecmtb05.org/). [18] Psiuk-Maksymowicz, K. and Mamontov, E., 2006, The homeorhesis-based modelling and fast numerical analysis for oncogenic hyperplasia under radiation therapy, submitted. [19] Mamontov, E., 2005, Nonstationary invariant distributions and the hydrodynamic-style generalization of the Kolmogorov-forward/Fokker-Planck equation, Appl. Math. Lett. 18 (9) 976-982.
  •  
21.
  • Zhang, Feng'e, et al. (author)
  • Cell cycle-related lncRNAs and mRNAs in osteoarthritis chondrocytes in a Northwest Chinese Han Population
  • 2020
  • In: Medicine. - : Lippincott Williams & Wilkins. - 0025-7974 .- 1536-5964. ; 99:24
  • Journal article (peer-reviewed)abstract
    • Background: A group of differentially expressed long non-coding RNAs (lncRNAs) have been shown to play key roles in osteoarthritis (OA), although they represented only a small proportion of lncRNAs that may be biologically and physiologically relevant. Since our knowledge of regulatory functions of non-coding RNAs is still limited, it is important to gain better understanding of their relation to the pathogenesis of OA.Methods: We performed mRNA and lncRNA microarray analysis to detect differentially expressed RNAs in chondrocytes from three OA patients compared with four healthy controls. Then, enrichment analysis of the differentially expressed mRNAs was carried out to define disease molecular networks, pathways and gene ontology (GO) function. Furthermore, target gene prediction based on the co-expression network was performed to reveal the potential relationships between lncRNAs and mRNAs, contributing an exploration of a role of lncRNAs in OA mechanism. Quantitative RT-PCR analyses were used to demonstrate the reliability of the experimental results.Findings: Altogether 990 lncRNAs (666 up-regulated and 324 down-regulated) and 546 mRNAs (419 up-regulated and 127 down-regulated) were differentially expressed in OA samples compared with the normal ones. The enrichment analysis revealed a set of genes involved in cell cycle. In total, 854 pairs of mRNA and lncRNA were highly linked, and further target prediction appointed 12 genes specifically for their corresponding lncRNAs. The lncRNAs lncRNA-CTD-2184D3.4, ENST00000564198.1, and ENST00000520562.1 were predicted to regulate SPC24, GALM, and ZNF345 mRNA expressions in OA.Interpretation: This study uncovered several novel genes potentially important in pathogenesis of OA, and forecast the potential function of lnc-CTD-2184D3.4, especially for the cell cycle in the chondrocytes. These findings may promote additional aspects in studies of OA.
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22.
  • Zhou, Tuping, et al. (author)
  • A Novel Method for Accurate One-dimensional Protein Structure Prediction Based on Fragment Matching
  • 2010
  • In: Bioinformatics. - : Oxford University Press (OUP). - 1367-4803 .- 1367-4811. ; 26:4, s. 470-477
  • Journal article (peer-reviewed)abstract
    • Motivation: The precise prediction of one-dimensional (1D) protein structure as represented by the protein secondary structure and 1D string of discrete state of dihedral angles (i.e. Shape Strings) is a prerequisite for the successful prediction of three-dimensional (3D) structure as well as protein-protein interaction. We have developed a novel 1D structure prediction method, called Frag1D, based on a straightforward fragment matching algorithm and demonstrated its success in the prediction of  three sets of 1D structural alphabets, i.e. the classical three-state secondary structure, three-state Shape Strings and eight-state Shape Strings. Results: By exploiting the vast protein sequence and protein structure data available, we have brought secondary structure prediction closer to the expected theoretical limit. When tested by a leave-one-out cross validation on a non-redundant set of PDB cutting at 30% sequence identity containing 5860 protein chains, the overall per-residue accuracy for secondary structure prediction, i.e. Q3 is 82.9%. The overall per-residue accuracy for three-state and eight-state Shape Strings are 85.1% and 71.5% respectively. We have also benchmarked our program with the latest version of PSIPRED for secondary structure prediction and our program predicted 0.3% better in Q3 when tested on 2241 chains with the same training set. For Shape Strings, we compared our method with a recently published method with the same dataset and definition as used by that method. Our program predicted at 2.2% better in accuracy for three-state Shape Strings. By quantitatively investigating the effect of data base size on 1D structure prediction we show that the accuracy increases by about 1% with every doubling of the database size.
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23.
  • Eriksson, Martin, 1970, et al. (author)
  • Triclosan changes community composition and selects for specific bacterial taxa in marine periphyton biofilms in low nanomolar concentrations
  • 2020
  • In: Ecotoxicology. - : Springer Science and Business Media LLC. - 0963-9292 .- 1573-3017. ; 29:7, s. 1083-1094
  • Journal article (peer-reviewed)abstract
    • The antibacterial agent Triclosan (TCS) is a ubiquitous environmental contaminant due to its widespread use. Sensitivity to TCS varies substantially among eu- and pro-karyotic species and its risk for the marine environment remains to be better elucidated. In particular, the effects that TCS causes on marine microbial communities are largely unknown. In this study we therefore used 16S amplicon rDNA sequencing to investigate TCS effects on the bacterial composition in marine periphyton communities that developed under long-term exposure to different TCS concentrations. Exposure to TCS resulted in clear changes in bacterial composition already at concentrations of 1 to 3.16 nM. We conclude that TCS affects the structure of the bacterial part of periphyton communities at concentrations that actually occur in the marine environment. Sensitive taxa, whose abundance decreased significantly with increasing TCS concentrations, include the Rhodobiaceae and Rhodobacteraceae families of Alphaproteobacteria, and unidentified members of the Candidate division Parcubacteria. Tolerant taxa, whose abundance increased significantly with higher TCS concentrations, include the families Erythrobacteraceae (Alphaproteobacteria), Flavobacteriaceae (Bacteroidetes), Bdellovibrionaceae (Deltaproteobacteria), several families of Gammaproteobacteria, and members of the Candidate phylum Gracilibacteria. Our results demonstrate the variability of TCS sensitivity among bacteria, and that TCS can change marine bacterial composition at concentrations that have been detected in the marine environment.
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24.
  • Saénz-de la O, Diana, et al. (author)
  • Antioxidant and drought‑acclimation responses in UV‑B‑exposed transgenic Nicotiana tabacum displaying constitutive overproduction of H2O2
  • 2023
  • In: Photochemical and Photobiological Sciences. - : Springer. - 1474-905X .- 1474-9092. ; 22:10, s. 2373-2387
  • Journal article (peer-reviewed)abstract
    • Hydrogen peroxide (H2O2) is an important molecule that regulates antioxidant responses that are crucial for plant stress resistance. Exposure to low levels of ultraviolet-B radiation (UV-B, 280–315 nm) can also activate antioxidant defenses and acclimation responses. However, how H2O2 and UV-B interact to promote stress acclimation remains poorly understood. In this work, a transgenic model of Nicotiana tabacum cv Xanthi nc, with elevated Mn-superoxide dismutase (Mn-SOD)activity, was used to study the interaction between the constitutive overproduction of H2O2 and a 14-day UV-B treatment (1.75 kJ m−2 d−1 biologically effective UV-B). Subsequently, these plants were subjected to a 7-day moderate drought treatment to evaluate the impact on drought resistance of H2O2- and UV-dependent stimulation of the plants' antioxidant system. The UV-B treatment enhanced H2O2 levels and altered the antioxidant status by increasing the epidermal flavonol index, Trolox Equivalent Antioxidant Capacity, and catalase, peroxidase and phenylalanine ammonia lyase activities in the leaves. UV-B also retarded growth and suppressed acclimation responses in highly H2O2-overproducing transgenic plants. Plants not exposed to UV-B had a higher drought resistance in the form of higher relative water content of leaves. Our data associate the interaction between Mn-SOD transgene overexpression and the UV-B treatment with a stress response. Finally, we propose a hormetic biphasic drought resistance response curve as a function of leaf H2O2 content in N. tabacum cv Xanthi.
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25.
  • Oelker, Melanie, 1988- (author)
  • Disarming bacteria : a structure-based approach to design an anti-virulence drug against Listeria monocytogenes
  • 2021
  • Doctoral thesis (other academic/artistic)abstract
    • Antibiotic resistances are one of the biggest threats to global health and if we don’t change our behavior and way of using antibiotics we will end up in a ‘post-antibiotic era’, in which common infections and minor injuries can once kill again and up to 10 million deaths per year may occur by 2050. Therefore, there is a high need for new anti-bacterial drugs, especially of alternatives to existing antibiotics with already described resistances. Classical antibiotics target the essential processes of survival and growth in bacteria and therefore put a high selective pressure on them to develop resistances. In contrast, the ability to infect or damage a host, the virulence, is less essential for bacteria. Thus, targeting the virulence is supposed to cause a lower selective pressure and this alternative mode-of-action could help to decelerate the development of antibiotic resistances.The aims in this work were to proceed with the structure-based design of an anti-virulence drug against the food-borne pathogen Listeria monocytogenes, but also to deepen our understanding of the complex regulation system for the virulence of this bacterium. PrfA, the master regulator of virulence in Listeria monocytogenes, is a member of a large family of bacterial transcription factors, which are regulated by a conformational change and allosteric modulation by different regulator molecules. Furthermore, its critical role in virulence regulations makes is a suitable target for an anti-virulence drug. In this work new lead compounds based on the previously identified ring-fused 2-pyridone scaffold were designed, synthesized and analyzed by different biological, biophysical, computational and structural biology methods. Three new binding sites and binding modes of these compounds in PrfA were evaluated for their potential use in future designs and a compound with improved activity was identified. In a second study another structurally different lead compound was discovered to inhibit PrfA. Furthermore, the studies on proposed natural regulators of PrfA uncovered the underlying mechanism for the virulence regulation by the peptide signature of the environment and in a follow-up study the structural basis of the binding of inhibitory peptides to PrfA was further investigated. Finally, a structural review on all available structure of PrfA provided more insights into the allosteric regulation mechanism of PrfA activity.This work will hopefully support in the successful development of an anti-virulence drug against Listeria monocytogenes and thus contribute to the reduction of the problem of antibiotic resistances.
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26.
  • Pienimaki, Juha-Pekka, et al. (author)
  • Epidermal growth factor activates hyaluronan synthase 2 in epidermal keratinocytes and increases pericellular and intracellular hyaluronan.
  • 2001
  • In: Journal of Biological Chemistry. - : American Society of Biochemistry and Molecular Biology. - 0021-9258 .- 1083-351X. ; 276:23, s. 20428-20435
  • Journal article (peer-reviewed)abstract
    • Hyaluronan is an abundant and rapidly turned over matrix molecule between the vital cell layers of the epidermis. In this study, epidermal growth factor (EGF) induced a coat of hyaluronan and a 3-5-fold increase in its rate of synthesis in a rat epidermal keratinocyte cell line that has retained its ability for differentiation. EGF also increased hyaluronan in perinuclear vesicles, suggesting concurrent enhancement in its endocytosis. Cell-associated hyaluronan was most abundant in elongated cells that were stimulated to migrate by EGF, as determined in vitro in a wound healing assay. Large fluctuations in the pool size of UDP-N-acetylglucosamine, the metabolic precursor of hyaluronan, correlated with medium glucose concentrations but not with EGF. Reverse transcriptase-polymerase chain reaction (RT-PCR) showed no increase in hyaluronan synthases 1 and 3 (Has1 and Has3), whereas Has2 mRNA increased 2-3-fold in less than 2 h following the introduction of EGF, as estimated by quantitative RT-PCR with a truncated Has2 mRNA internal standard. The average level of Has2 mRNA increased from approximately 6 copies/cell in cultures before change of fresh medium, up to approximately 54 copies/cell after 6 h in EGF-containing medium. A control medium with 10% serum caused a maximum level of approximately 21 copies/cell at 6 h. The change in the Has2 mRNA levels and the stimulation of hyaluronan synthesis followed a similar temporal pattern, reaching a maximum level at 6 h and declining toward 24 h, a finding in line with a predominantly Has2-dependent hyaluronan synthesis and its transcriptional regulation.
  •  
27.
  • Rilla, Kirsi, et al. (author)
  • Changed lamellipodial extension, adhesion plaques and migration in epidermal keratinocytes containing constitutively expressed sense and antisense hyaluronan synthase 2 (Has2) genes.
  • 2002
  • In: Journal of Cell Science. - Cambridge : The Company of Biologists. - 0021-9533 .- 1477-9137. ; 115, s. 3633-3643
  • Journal article (peer-reviewed)abstract
    • Hyaluronan is a major component of the epidermal extracellular matrix, is actively synthesized by keratinocytes and shows fast matrix turnover in the stratified epithelium. We probed the importance of hyaluronan synthesis in keratinocytes by establishing cell lines carrying the exogenous hyaluronan synthase 2 (Has2) gene in sense and antisense orientations to increase and decrease their hyaluronan synthesis, respectively. Compared with cell lines transfected with the vector only, most clones containing the Has2 sense gene migrated faster in an in vitro wounding assay, whereas Has2 antisense cells migrated more slowly. Has2 antisense clones showed delayed entry into the S phase of cell cycle following plating, smaller lamellipodia and less spreading on the substratum. The decrease of hyaluronan on the undersurface of Has2 antisense cells was associated with an increased area of adhesion plaques containing vinculin. Exogenous hyaluronan added to the keratinocyte cultures had a minor stimulatory effect on migration after wounding but did not restore the reduced migratory ability of Has2 antisense cells. Hyaluronan decasaccharides that displace receptor bound hyaluronan in keratinocytes, and Streptomyces hyaluronidase sufficient to remove most cell surface hyaluronan had little effect on cell migration. The results suggest that the dynamic synthesis of hyaluronan directed by Has2, rather than the abundance of pericellular hyaluronan, controls keratinocyte migration, a cell function vital for the repair of squamous epithelia following wounding.
  •  
28.
  • Kalbina, Irina, et al. (author)
  • Two separate UV-B radiation wavelength regions control expression of different molecular markers in Arabidopsis thaliana
  • 2008
  • In: Functional Plant Biology. - Collinwood VIC : CSIRO. - 1445-4408 .- 1445-4416. ; 35:3, s. 222-227
  • Journal article (peer-reviewed)abstract
    • Fluence-response curves were obtained at nine wavelengths in the interval 280-360 nm for mRNA transcripts of four molecular markers induced by ultraviolet-B (UV-B) radiation in Arabidopsis thaliana: CHS (encoding chalcone synthase), PDX1.3 (encoding an enzyme involved in formation of pyridoxine), MEB5.2 (encoding a protein with unknown function but which is strongly up-regulated by UV-B), and LHCB1*3 (encoding a chlorophyll a/b binding protein). Intact Arabidopsis plants were irradiated for 3h using a high intensity deuterium radiation source and narrow bandwith filters (Kalbin et al. 2005, J. Biochem. Biophys. Meth. 65, 1-12) without supplementary PAR. The results obtained suggest the existence of two distinct UV-B signal responses: one sensitive between 300 and 310 nm and the other sensitive around 280-290 nm. Among the investigated molecular markers, CHS and PDX1.3 were regulated through the chromophore absorbing around 300 nm, whereas MEB5.2 and LHCB1*3 were regulated through the chromophore absorbing at 280-290 nm. The results obtained show that at least two signal transduction pathways exist that regulate gene expression as a result of absorption of UV-B radiation in plants.
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29.
  •  
30.
  • Kuktaite, Ramune, et al. (author)
  • Structure and Morphology of Wheat Gluten Films : From Polymeric Protein Aggregates toward Superstructure Arrangements
  • 2011
  • In: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 12:5, s. 1438-1448
  • Journal article (peer-reviewed)abstract
    • Evaluation of structure and morphology of extruded wheat gluten (WG) films showed WG protein assemblies elucidated on a range of length scales from nano (4.4 angstrom and 9 to 10 angstrom, up to 70 angstrom) to micro (10 mu m). The presence of NaOH in WG films induced a tetragonal structure with unit cell parameters, a = 51.85 angstrom and c = 40.65 angstrom, whereas NH4OH resulted in a bidimensional hexagonal close-packed (HCP) structure with a lattice parameter of 70 angstrom. In the WG films with NH4OH, a highly polymerized protein pattern with intimately mixed glutenins and gliadins bounded through SH/SS interchange reactions was found. A large content of beta-sheet structures was also found in these films, and the film structure was oriented in the extrusion direction. In conclusion, this study highlights complexities of the supramolecular structures and conformations of wheat gluten polymeric proteins in biofilms not previously reported for biobased materials.
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31.
  • Xu, Bo, 1980- (author)
  • Evolutionary and Pharmacological Studies of NPY and QRFP Receptors
  • 2014
  • Doctoral thesis (other academic/artistic)abstract
    • The neuropeptide Y (NPY) system consists of 3-4 peptides and 4-7 receptors in vertebrates. It has powerful effects on appetite regulation and is involved in many other biological processes including blood pressure regulation, bone formation and anxiety. This thesis describes studies of the evolution of the NPY system by comparison of several vertebrate species and structural studies of the human Y2 receptor, which reduces appetite, to identify amino acid residues involved in peptide-receptor interactions.The NPY system was studied in zebrafish (Danio rerio), western clawed frog (Xenopus tropicalis), and sea lamprey (Petromyzon marinus). The receptors were cloned and functionally expressed and their pharmacological profiles were determined using the native peptides in either binding studies or a signal transduction assay. Some peptide-receptor preferences were observed, indicating functional specialization.A receptor family closely related to the NPY receptors, called the QRFP receptors, was investigated. A QRFP receptor was cloned from amphioxus, Branchistoma floridae, showing that the receptor arose before the origin of the vertebrates. Evolutionary studies demonstrated that the ancestral vertebrate had as many as four QRFP receptors, only one of which remains in mammals today. This correlates with the NPY receptor family, located in the same chromosomal regions, which had seven members in the ancestral vertebrate but only 4-5 in living mammals. Some vertebrates have considerably more complex NPY and QRFP receptor systems than humans and other mammals.Two studies investigated interactions of NPY-family peptides with the human Y2 receptor. Candidate residues, selected based on structural modeling and docking, were mutated to disrupt possible interactions with peptide ligands. The modified receptors were expressed in cultured cells and investigated by measuring binding and functional responses. Several receptor residues were found to influence peptide-receptor interactions, some of which are involved in maintaining receptor structure. In a pilot study, the kinetics of peptide-receptor interaction were found to be very slow, of the order several hours.In conclusion, this thesis clarifies evolutionary relationships for the complex NPY and QRFP peptide-receptor systems and improves the structural models of the human NPY-family receptors, especially Y2. These results will hopefully facilitate drug design for targeting of NPY-family receptors.
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32.
  • Falk Erhag, Hanna, et al. (author)
  • A Multidisciplinary Approach to Capability in Age and Ageing
  • 2022
  • Book (other academic/artistic)abstract
    • This open access book provides insight on how to interpret capability in ageing – one’s individual ability to perform actions in order to reach goals one has reason to value – from a multidisciplinary approach. With for the first time in history there being more people in the world aged 60 years and over than there are children below the age of 5, the book describes this demographic trends as well as the large global challenges and important societal implications this will have such as a worldwide increase in the number of persons affected with dementia, and in the ratio of retired persons to those still in the labor market. Through contributions from many different research areas, it discussed how capability depends on interactions between the individual (e.g. health, genetics, personality, intellectual capacity), environment (e.g. family, friends, home, work place), and society (e.g. political decisions, ageism, historical period). The final chapter by the editors summarizes the differences and similarities in these contributions. As such this book provides an interesting read for students, teachers and researchers at different levels and from different fields interested in capability and multidisciplinary research.
  •  
33.
  • Kaarniranta, Kai, et al. (author)
  • Primary chondrocytes resist hydrostatic pressure-induced stress while primary synovial cells and fibroblasts show modified Hsp70 response.
  • 2001
  • In: Osteoarthritis and Cartilage. - : Saunders Elsevier. - 1063-4584 .- 1522-9653. ; 9:1, s. 7-13
  • Journal article (peer-reviewed)abstract
    • OBJECTIVE: During joint loading, chondrocytes in the articular cartilage are subjected to gradients of high compressive hydrostatic pressure (HP). In response to diverse chemical or physical stresses, heat shock genes are induced to express heat shock proteins (Hsps). This study sought to examine the role of Hsps in baroresistance in primary bovine chondrocytes and synovial cells, as well as in primary human fibroblasts.METHODS: Northern blotting was used to analyze the steady-state levels of hsp70 mRNA in the primary cells exposed to HP or heat stress. Hsp70 protein accumulation was analyzed by Western blotting, and the DNA-binding activity was examined by gel mobility shift assay.RESULTS: Primary bovine chondrocytes which have been adapted to live under pressurized conditions showed negligible Hsp70 response upon HP loading, whereas primary bovine synovial cells and human fibroblasts accumulated hsp70 mRNA and protein when subjected to HP. The response was initiated without activation of the heat shock transcription factor 1. Interestingly, pre-conditioning of the barosensitive fibroblasts with HP or heat shock reduced the Hsp70 response, indicating induction of baroresistance.CONCLUSION: This study suggests that Hsp70 can play an important role in the early stages of adaptation of cells to HP. Thus, the Hsp70 gene expression upon HP loading may serve as one indicator of the chondrocytic phenotype of the cells. This can be of use in the treatment of cartilage lesions.
  •  
34.
  • Zhao, Guang-Hui, et al. (author)
  • A preliminary analysis of microRNA profiles in the subchondral bone between Kashin-Beck disease and primary knee osteoarthritis
  • 2019
  • In: Clinical Rheumatology. - : Springer Science and Business Media LLC. - 0770-3198 .- 1434-9949. ; 38:9, s. 2637-2645
  • Journal article (peer-reviewed)abstract
    • INTRODUCTION: Kashin-Beck disease (KBD) is a chronic osteochondral disorder primarily associated with cartilage degeneration. The bone texture structure in KBD was also changed but it was not identical to primary knee osteoarthritis (OA). This study investigates the differences in microRNA (miRNA) profiles of subchondral bone collected from patients suffering from KBD in comparison with those with primary knee osteoarthritis (OA).METHODS: Subchondral bone tissues were taken from four patients with KBD and four patients with primary knee OA undergoing total knee replacement. The miRNA array profiling was performed using an Affymetrix miRNA 4.0 Array, and then the target gene predictions and function annotations of the predicted targets were performed.RESULTS: Our results showed that 124 miRNAs had lower expression levels in the subchondral bone sampled from KBD patients in comparison with OA patients. Gene ontology (GO) and KEGG pathway analyses of the predicted targets demonstrated numerous significantly enriched GO terms and signal pathways essential for bone development and integrity, such as metabolic processes, PI3K-Akt, and MAPK signaling pathways.CONCLUSIONS: Our study confirms that a large set of miRNAs are differentially expressed in the subchondral bone of patients with KBD and OA and contributes new insights into potential pathological changes in the subchondral bone of KBD patients.
  •  
35.
  • Zhao, M., et al. (author)
  • Phylogenetic position of the Wallcreeper Tichodroma muraria
  • 2016
  • In: Journal of Ornithology = Journal fur Ornithologie. - : Springer Science and Business Media LLC. - 0021-8375 .- 1439-0361. ; 157:3, s. 913-918
  • Journal article (peer-reviewed)abstract
    • The Wallcreeper Tichodroma muraria is usually placed in a monotypic family or subfamily within the superfamily Certhioidea, with assumed close relationships to Certhia (treecreepers), Sitta (nuthatches) and Salpornis (spotted creepers). Previous studies have suggested that Tichodroma is most closely related to Sitta, alternatively to Salpornis. We analysed the relationships of Tichodroma using two mitochondrial and five nuclear loci. The tree based on concatenated sequences strongly supported a sister relationship between Tichodroma and Sitta, as well as between Salpornis and Certhia. However, species tree analysis (MP-EST) was unable to resolve these relationships, and although the concatenation tree remains the best hypothesis, more data are needed to corroborate this. © 2016, Dt. Ornithologen-Gesellschaft e.V.
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36.
  • Mamontov, Eugen, 1955, et al. (author)
  • The minimal, phase-transition model for the cell-number maintenance by the hyperplasia-extended homeorhesis
  • 2006
  • In: Acta Biotheoretica. - : Springer Science and Business Media LLC. - 0001-5342 .- 1572-8358. ; 54:2, s. 61-101
  • Journal article (peer-reviewed)abstract
    • Oncogenic hyperplasia is the first and inevitable stage of formation of a (solid) tumor. This stage is also the core of many other proliferative diseases. The present work proposes the first minimal model that combines homeorhesis with oncogenic hyperplasia where the latter is regarded as a genotoxically activated homeorhetic dysfunction. This dysfunction is specified as the transitions of the fluid of cells from a fluid, homeorhetic state to a solid, hyperplastic-tumor state, and back. The key part of the model is a nonlinear reaction-diffusion equation (RDE) where the biochemical-reaction rate is generalized to the one in the well-known Schlögl physical theory of the non-equilibrium phase transitions. A rigorous analysis of the stability and qualitative aspects of the model, where possible, are presented in detail. This is related to the spatially homogeneous case, i.e. when the above RDE is reduced to a nonlinear ordinary differential equation. The mentioned genotoxic activation is treated as a prevention of the quiescent G0-stage of the cell cycle implemented with the threshold mechanism that employs the critical concentration of the cellular fluid and the nonquiescent-cell-duplication time. The continuous tumor morphogeny is described by a time-space-dependent cellular-fluid concentration. There are no sharp boundaries (i.e. no concentration jumps exist) between the domains of the homeorhesis- and tumor-cell populations. No presumption on the shape of a tumor is used. To estimate a tumor in specific quantities, the model provides the time-dependent tumor locus, volume, and boundary that also points out the tumor shape and size. The above features are indispensable in the quantitative development of antiproliferative drugs or therapies and strategies to prevent oncogenic hyperplasia in cancer and other proliferative diseases. The work proposes an analytical-numerical method for solving the aforementioned RDE. A few topics for future research are suggested.
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37.
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38.
  • Nilsson, R. Henrik, 1976, et al. (author)
  • A software pipeline for processing and identification of fungal ITS sequences
  • 2009
  • In: Source Code for Biology and Medicine. - 1751-0473. ; 4:1
  • Journal article (peer-reviewed)abstract
    • Background Fungi from environmental samples are typically identified to species level through DNA sequencing of the nuclear ribosomal internal transcribed spacer (ITS) region for use in BLAST-based similarity searches in the International Nucleotide Sequence Databases. These searches are time-consuming and regularly require a significant amount of manual intervention and complementary analyses. We here present software - in the form of an identification pipeline for large sets of fungal ITS sequences - developed to automate the BLAST process and several additional analysis steps. The performance of the pipeline was evaluated on a dataset of 350 ITS sequences from fungi growing as epiphytes on building material. Results The pipeline was written in Perl and uses a local installation of NCBI-BLAST for the similarity searches of the query sequences. The variable subregion ITS2 of the ITS region is extracted from the sequences and used for additional searches of higher sensitivity. Multiple alignments of each query sequence and its closest matches are computed, and query sequences sharing at least 50 % of their best matches are clustered to facilitate the evaluation of hypothetically conspecific groups. The pipeline proved to speed up the processing, as well as enhance the resolution, of the evaluation dataset considerably, and the fungi were found to belong chiefly to the Ascomycota, with Penicillium and Aspergillus as the two most common genera. The ITS2 was found to indicate a different taxonomic affiliation than did the complete ITS region for 10 % of the query sequences, though this figure is likely to vary with the taxonomic scope of the query sequences. Conclusions The present software readily assigns large sets of fungal query sequences to their respective best matches in the international sequence databases and places them in a larger biological context. The output is highly structured to be easy to process, although it still needs to be inspected and possibly corrected for the impact of the incomplete and sometimes erroneously annotated fungal entries in these databases. The open source pipeline is available for UNIX-type platforms, and updated releases of the target database are made available biweekly. The pipeline is easily modified to operate on other molecular regions and organism groups.
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39.
  • Siddique, Abu Bakar, First research engineer, et al. (author)
  • What do we learn from cultures in the omics age? High-throughput sequencing and cultivation of leaf-inhabiting endophytes from beech (Fagus sylvatica L.) revealed complementary community composition but similar correlations with local habitat conditions
  • 2017
  • In: MycoKeys. - : Pensoft Publishers. - 1314-4057 .- 1314-4049. ; 20, s. 1-16
  • Journal article (peer-reviewed)abstract
    • Comparative simultaneous studies of environmental high-throughput sequencing (HTS) and cultivation of plant-associated fungi have rarely been conducted in the past years. For the present contribution, HTS and extinction culturing were applied for the same leaf samples of European beech (Fagus sylvatica) in order to trace both “real” environmental drivers as well as method-dependent signals of the observed mycobiomes. Both approaches resulted in non-overlapping community composition and pronounced differences in taxonomic classification and trophic stages. However, both methods revealed similar correlations of the fungal communities with local environmental conditions. Our results indicate undeniable advantages of HTS over cultivation in terms of revealing a good representation of the major functional guilds, rare taxa and biodiversity signals of leaf-inhabiting fungi. On the other hand our results demonstrate that the immense body of literature about cultivable endophytic fungi can and should be used for the interpretation of community signals and environmental correlations obtained from HTS studies and that cultivation studies should be continued at the highest standards, e.g. when sequencing facilities are not available or if such surveys are expanded into functional aspects with experiments on living isolates.
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40.
  • Solinas, Giovanni, et al. (author)
  • An adipoincretin effect links adipostasis with insulin secretion.
  • 2024
  • In: Trends in endocrinology and metabolism: TEM. - 1879-3061. ; 35:6, s. 466-477
  • Research review (peer-reviewed)abstract
    • The current paradigm for the insulin system focuses on the phenomenon of glucose-stimulated insulin secretion and insulin action on blood glucose control. This historical glucose-centric perspective may have introduced a conceptual bias in our understanding of insulin regulation. A body of evidence demonstrating that in vivo variations in blood glucose and insulin secretion can be largely dissociated motivated us to reconsider the fundamental design of the insulin system as a control system for metabolic homeostasis. Here, we propose that a minimal glucose-centric model does not accurately describe the physiological behavior of the insulin system and propose a new paradigm focusing on the effects of incretins, arguing that under fasting conditions, insulin is regulated by an adipoincretin effect.
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41.
  • Lindahl, Björn, et al. (author)
  • Fungal community analysis by high-throughput sequencing of amplified markers – a user's guide
  • 2013
  • In: New Phytologist. - : Wiley. - 0028-646X .- 1469-8137. ; 199:1, s. 288-299
  • Research review (peer-reviewed)abstract
    • * Novel high-throughput sequencing methods outperform earlier approaches in terms of resolution and magnitude. They enable identification and relative quantification of community members and offer new insights into fungal community ecology. These methods are currently taking over as the primary tool to assess fungal communities of plant-associated endophytes, pathogens, and mycorrhizal symbionts, as well as free-living saprotrophs. * Taking advantage of the collective experience of six research groups, we here review the different stages involved in fungal community analysis, from field sampling via laboratory procedures to bioinformatics and data interpretation. We discuss potential pitfalls, alternatives, and solutions. * Highlighted topics are challenges involved in: obtaining representative DNA/RNA samples and replicates that encompass the targeted variation in community composition, selection of marker regions and primers, options for amplification and multiplexing, handling of sequencing errors, and taxonomic identification. * Without awareness of methodological biases, limitations of markers, and bioinformatics challenges, large-scale sequencing projects risk yielding artificial results and misleading conclusions.
  •  
42.
  • Sorour, Ashraf E., et al. (author)
  • Evaluation of hepatocyte growth factor as a local acute phase response marker in the bowel : the clinical impact of a rapid diagnostic test for immediate identification of acute bowel inflammation
  • 2015
  • In: Cytokine. - : Elsevier BV. - 1043-4666 .- 1096-0023. ; 71:1, s. 8-15
  • Journal article (peer-reviewed)abstract
    • Background: There are no rapid tests that can distinguish contagious gastroenteritis, which requires isolation at its onset, from exacerbation of chronic inflammatory bowel disease (IBD) or bowel engagement in the course of systemic inflammatory response syndrome (SIRS). Hepatocyte growth factor (HGF) is an acute phase cytokine that is produced at the site of injury. It has high affinity to sulfated glycan, and this binding affinity is lost during chronic inflammation. The fecal pH strongly impacts the prognosis for severe bowel disease. We developed a strip test to evaluate HGF as a local acute phase response marker in the bowel. This test assessed the binding affinity of HGF to sulfated glycans in fecal samples and determined fecal pH as an indicator of illness severity.Methods: Fresh feces from patients with diarrhea (n = 513) were collected and tested blindly, and information about patient illness course and outcome was collected. Patients were classified based on the focus of inflammation and the cause of the symptoms. Objectively verified diagnoses of infectious gastroenteritis (n = 131) and IBD onset/exacerbation and bowel cancer (n = 44) were used to estimate the performance of the test strip. ELISA was performed on 101 freeze-thawed feces samples to determine the fecal HGF levels.Results: The test rapidly distinguished infectious gastroenteritis from non-infectious inflammatory causes of diarrhea (sensitivity, 87.96%; specificity, 90.9%; positive predictive value, 96.6%; negative predictive value, 71.4%; accuracy, 89.1%). Fecal pH (p < 0.0001) and mortality within 28 days of sampling (p < 0.04) was higher in patients with sepsis/SIRS and diarrhea. The concentration of HGF was higher in strip test-positive stool samples (p < 0.01).Conclusions: HGF is a good local acute phase response marker of acute bowel inflammation. Test-strip determination of the binding affinity of fecal HGF to sulfated glycan was a rapid, equipment-free way to assess patients with diarrhea and to guide the diagnostic and therapeutic approaches on admission. (C) 2014 The Authors. Published by Elsevier Ltd.
  •  
43.
  • Tavella, T A, et al. (author)
  • Yeast-based high-throughput screens for discovery of kinase inhibitors for neglected diseases.
  • 2021
  • In: Advances in Protein Chemistry and Structural Biology. - : Elsevier. - 1876-1631. ; 124, s. 275-309
  • Research review (peer-reviewed)abstract
    • The discovery and development of a new drug is a complex, time consuming and costly process that typically takes over 10 years and costs around 1 billion dollars from bench to market. This scenario makes the discovery of novel drugs targeting neglected tropical diseases (NTDs), which afflict in particular people in low-income countries, prohibitive. Despite the intensive use of High-Throughput Screening (HTS) in the past decades, the speed with which new drugs come to the market has remained constant, generating doubts about the efficacy of this approach. Here we review a few of the yeast-based high-throughput approaches that can work synergistically with parasite-based, in vitro, or in silico methods to identify and optimize novel antiparasitic compounds. These yeast-based methods range from HTP screens to identify novel hits against promising parasite kinase targets to the identification of potential antiparasitic kinase inhibitors extracted from databases of yeast chemical genetic screens.
  •  
44.
  • Subhash, Santhilal, 1987, et al. (author)
  • Sperm Originated Chromatin Imprints and LincRNAs in Organismal Development and Cancer
  • 2020
  • In: iScience. - : Elsevier BV. - 2589-0042. ; 23:6
  • Journal article (peer-reviewed)abstract
    • Importance of sperm-derived transcripts and chromatin imprints in organismal development is poorly investigated. Here using an integrative approach, we show that human sperm transcripts are equally important as oocyte. Sperm-specific and sperm-oocyte common transcripts carry distinct chromatin structures at their promoters correlating with corresponding transcript levels in sperm. Interestingly, sperm-specific H3K4me3 patterns at the lincRNA promoters are not maintained in the germ layers and somatic tissues. However, bivalent chromatin at the sperm-specific protein-coding gene promoters is maintained throughout the development. Sperm-specific transcripts reach their peak expression during zygotic genome activation, whereas sperm-oocyte common transcripts are present during early preimplantation development but decline at the onset of zygotic genome activation. Additionally, there is an inverse correlation between sperm-specific and sperm-oocyte lincRNAs throughout the development. Sperm-lincRNAs also show aberrant activation in tumors. Overall, our observations indicate that sperm transcripts carrying chromatin imprints may play an important role in human development and cancer.
  •  
45.
  • Kaarniranta, Kai, et al. (author)
  • Neuronal cells show regulatory differences in the hsp70 gene response.
  • 2002
  • In: Brain Research. Molecular Brain Research. - : Elsevier. - 0169-328X .- 1872-6941. ; 101:1-2, s. 136-140
  • Journal article (peer-reviewed)abstract
    • The synthesis of heat shock proteins (Hsps), encoded by heat shock genes, is increased in response to various stress stimuli. Hsps function as molecular chaperones, they dissociate cytotoxic stress-induced protein aggregates within cells and ensure improved survival. Induction of heat shock genes is mainly regulated at the transcriptional level. The stress responsive transcription factor, heat shock factor 1 (HSF1), is involved in the transcriptional induction of the heat shock genes. Our objective was to examine how hsp70 genes are regulated in different transformed and primary neurons upon exposure to elevated temperature. Our findings reveal that the Hsp70 response is regulated at the translational level in Neuro-2a neuroblastoma cells, while the IMR-32 neuroblastoma cells respond to stress by the classical HSF1-driven transcriptional regulatory mechanism. Primary rat hippocampal neurons show a lack of HSF1 and induction of the hsp70 gene. These observations suggest that neuronal cells display different hsp70 gene expression patterns which range from undetected response to transcriptional and posttranscriptional regulation during heat stress.
  •  
46.
  • Nelimarkka, Lassi, et al. (author)
  • Expression of small extracellular chondroitin/dermatan sulfate proteoglycans is differentially regulated in human endothelial cells.
  • 1997
  • In: Journal of Biological Chemistry. - : Elsevier BV. - 0021-9258 .- 1083-351X. ; 272:19, s. 12730-12737
  • Journal article (peer-reviewed)abstract
    • We have examined the expression of the small extracellular chondroitin/dermatan sulfate proteoglycans (CS/DS PGs), biglycan, decorin, and PG-100, which is the proteoglycan form of colony stimulating factor-1, in the human endothelial cell line EA.hy 926. We have also examined whether modulation of the phenotype of EA.hy 926 cells by tumor necrosis factor-alpha (TNF-alpha) is associated with specific changes in the synthesis of these PGs. We demonstrate that EA.hy 926 cells, when they form monolayer cultures typical of macrovascular endothelial cells, express and synthesize detectable amounts of biglycan and PG-100, but not decorin. On SDS-polyacrylamide gel electrophoresis both PGs behave like proteins of the relative molecular weight of approximately 250,000. TNF-alpha that changed the morphology of the cells from a polygonal shape into a spindle shape and that also stimulated the detachment of the cells from culture dish, markedly decreased the net synthesis of biglycan, whereas the net synthesis of PG-100 was increased. These changes were parallel with those observed at the mRNA level of the corresponding PGs. The proportions of the different sulfated CS/DS disaccharide units of PGs were not affected by TNF-alpha. Several other growth factors/cytokines, such as interferon-gamma, fibroblast growth factors-2 (FGF-2) and -7 (FGF-7), interleukin-1beta, and transforming growth factor-beta, unlike TNF-alpha, modulated neither the morphology nor the biglycan expression of EA.hy 926 cells under the conditions used in the experiments. However, PG-100 expression was increased also in response to FGF-2 and -7 and transforming growth factor-beta. None of the above cytokines, including TNF-alpha, was able to induce decorin expression in the cells. Our results indicate that the regulatory elements controlling the expression of the small extracellular CS/DS PGs in human endothelial cells are different.
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47.
  •  
48.
  • Eriksson, Martin, 1970, et al. (author)
  • Community-Level Analysis of psbA Gene Sequences and Irgarol Tolerance in Marine Periphyton
  • 2009
  • In: Applied and Environmental Microbiology. - Washington, D.C. : American Society for Microbiology. - 0099-2240 .- 1098-5336. ; 75:4, s. 897-906
  • Journal article (peer-reviewed)abstract
    • This study analyzes psbA gene sequences, predicted D1 protein sequences, species relative abundance, and pollution-induced community tolerance in marine periphyton communities exposed to the antifouling compound Irgarol 1051. The mechanism of action of Irgarol is the inhibition of photosynthetic electron transport at photosystem II by binding to the D1 protein. The metagenome of the communities was used to produce clone libraries containing fragments of the psbA gene encoding the D1 protein. Community tolerance was quantified with a short-term test for the inhibition of photosynthesis. The communities were established in a continuous flow of natural seawater through microcosms with or without added Irgarol. The selection pressure from Irgarol resulted in an altered species composition and an inducted community tolerance to Irgarol. Moreover, there was a very high diversity in the psbA gene sequences in the periphyton, and the composition of psbA and D1 fragments within the communities was dramatically altered by increased Irgarol exposure. Even though tolerance to this type of compound in land plants often depends on a single amino acid substitution (Ser(264)-> Gly) in the D1 protein, this was not the case for marine periphyton species. Instead, the tolerance mechanism likely involves increased degradation of D1. When we compared sequences from low and high Irgarol exposure, differences in nonconserved amino acids were found only in the so-called PEST region of D1, which is involved in regulating its degradation. Our results suggest that environmental contamination with Irgarol has led to selection for high-turnover D1 proteins in marine periphyton communities at the west coast of Sweden.
  •  
49.
  •  
50.
  • Sahlman, Janne, et al. (author)
  • Premature vertebral endplate ossification and mild disc degeneration in mice after inactivation of one allele belonging to the Col2a1 gene for Type II collagen.
  • 2001
  • In: Spine. - : Lippincott Williams & Wilkins. - 0362-2436 .- 1528-1159. ; 26:23, s. 2558-2565
  • Journal article (peer-reviewed)abstract
    • STUDY DESIGN: Skeletal tissues of mice with an inactivated allele of the Col2a1 gene for Type II collagen ("heterozygous knockout") were studied.OBJECTIVE: To determine whether a heterozygous inactivation of the Col2a1 gene has a role in the etiology of spine disorders such as disc degeneration.SUMMARY OF BACKGROUND DATA: Mutations in the COL2A1, COL11A1, COL11A2, and COL9A2 genes have been linked to spine disorders. However, the mechanism by which genetic factors lead to disc degeneration still are largely unknown.METHODS: Spine tissues were studied using radiograph analyses; conventional, quantitative, and polarized light microscopy; immunohistochemistry for the major extracellular components, and in situ hybridization for procollagens alpha1(I) and alpha1(II). Voluntary running activity also was monitored in half of the mice.RESULTS: As the findings showed, 1-month-old heterozygous knockout mice had shorter limb bones, skulls, and spines, as well as thicker and more irregular vertebral endplates, which calcified earlier than in the control mice. They also had a lower concentration of glycosaminoglycans in the anulus fibrosus, in the endplates, and in the vertebral bone than the controls. These features in the heterozygous knockout mice were compensated by the age of 15 months. However, the long bones and skulls of the mature heterozygous mice remained shorter than those of the controls. Gene-deficient mice used the running wheel less. However, physical exercise did not induce any marked structural changes in the skeleton.CONCLUSION: Mice with heterozygous knockout of Col2a1 show subtle early skeletal manifestations that bear some resemblance to those of human spine disorders.
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