| 1. |
- Alalam, Hanna, et al.
(författare)
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Conjugation factors controlling F-plasmid antibiotic resistance transmission
- 2018
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Ingår i: BioRxiv. - : Cold Spring Harbor Laboratory.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The rapid horizontal transmission of many antibiotic resistance genes between bacterial host cells on conjugative plasmids is a major cause of the accelerating antibiotic resistance crisis. Preventing understanding and targeting conjugation, there currently are no experimental platforms for fast and cost-efficient screening of genetic effects on antibiotic resistance transmission by conjugation. We introduce a novel experimental framework to screen for conjugation based horizontal transmission of antibiotic resistance between >60,000 pairs of cell populations in parallel. Plasmid-carrying donor strains are constructed in high throughput. We then mix the resistance plasmid carrying donors with recipients in a design where only transconjugants can reproduce, measure growth in dense intervals and extract transmission times as the growth lag. As proof-of-principle, we exhaustively explored chromosomal genes controlling F plasmid donation within E. coli populations, by screening the Keio deletion collection at high replication. We recover all six known chromosomal gene mutants affecting conjugation and identify >50 novel factors, all of which diminish antibiotic resistance transmission. We verify 10 of the novel genes' effects in a liquid mating assay. The new framework holds great potential for exhaustive disclosing of candidate targets for helper drugs that delay resistance development in patients and societies and improves the longevity of current and future antibiotics.
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| 2. |
- Alao, John Patrick, 1973, et al.
(författare)
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Suppression of sensitivity to drugs and antibiotics by high external cation concentrations in fission yeast
- 2015
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Ingår i: PLoS One. - : Public Library of Science (PLoS). - 1932-6203. ; 10:3
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Tidskriftsartikel (refereegranskat)abstract
- Background Potassium ion homeostasis plays an important role in regulating membrane potential and therefore resistance to cations, antibiotics and chemotherapeutic agents in Schizosaccharomyces pombe and other yeasts. However, the precise relationship between drug resistance in S. pombe and external potassium concentrations (particularly in its natural habitats) remains unclear. S. pombe can tolerate a wide range of external potassium concentrations which in turn affect plasma membrane polarization. We thus hypothesized that high external potassium concentrations suppress the sensitivity of this yeast to various drugs. Methods We have investigated the effect of external KCl concentrations on the sensitivity of S. pombe cells to a wide range of antibiotics, antimicrobial agents and chemotherapeutic drugs. We employed survival assays, immunoblotting and microscopy for these studies. Results We demonstrate that KCl, and to a lesser extent NaCl and RbCl can suppress the sensitivity of S. pombe to a wide range of antibiotics. Ammonium chloride and potassium hydrogen sulphate also suppressed drug sensitivity. This effect appears to depend in part on changes to membrane polarization and membrane transport proteins. Interestingly, we have found little relationship between the suppressive effect of KCl on sensitivity and the structure, polarity or solubility of the various compounds investigated. Conclusions High concentrations of external potassium and other cations suppress sensitivity to a wide range of drugs in S. pombe. Potassium-rich environments may thus provide S. pombe a competitive advantage in nature. Modulating potassium ion homeostasis may sensitize pathogenic fungi to antifungal agents.
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| 3. |
- Bourgard, Catarina, 1985, et al.
(författare)
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Plasmodium vivax Biology: Insights Provided by Genomics, Transcriptomics and Proteomics.
- 2018
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Ingår i: Frontiers in Cellular and Infection Microbiology. - : Frontiers Media SA. - 2235-2988. ; 8
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Forskningsöversikt (refereegranskat)abstract
- During the last decade, the vast omics field has revolutionized biological research, especially the genomics, transcriptomics and proteomics branches, as technological tools become available to the field researcher and allow difficult question-driven studies to be addressed. Parasitology has greatly benefited from next generation sequencing (NGS) projects, which have resulted in a broadened comprehension of basic parasite molecular biology, ecology and epidemiology. Malariology is one example where application of this technology has greatly contributed to a better understanding ofPlasmodiumspp. biology and host-parasite interactions. Among the several parasite species that cause human malaria, the neglected Plasmodium vivax presents great research challenges, asin vitroculturing is not yet feasible and functional assays are heavily limited. Therefore, there are gaps in our P. vivax biology knowledge that affect decisions for control policies aiming to eradicate vivax malaria in the near future. In this review, we provide a snapshot of key discoveries already achieved in P. vivax sequencing projects, focusing on developments, hurdles, and limitations currently faced by the research community, as well as perspectives on future vivax malaria research.
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| 4. |
- Ferreira, Letícia T, et al.
(författare)
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Chemical Genomic Profiling Unveils the in Vitro and in Vivo Antiplasmodial Mechanism of Açaí (Euterpe oleracea Mart.) Polyphenols.
- 2019
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Ingår i: ACS Omega. - : American Chemical Society (ACS). - 2470-1343. ; 4:13, s. 15628-15635
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Tidskriftsartikel (refereegranskat)abstract
- Malaria remains a major detrimental parasitic disease in the developing world, with more than 200 million cases annually. Widespread drug-resistant parasite strains push for the development of novel antimalarial drugs. Plant-derived natural products are key sources of antimalarial molecules. Euterpe oleracea Martius ("açaí") originates from Brazil and has anti-inflammatory and antineoplasic properties. Here, we evaluated the antimalarial efficacy of three phenolic fractions of açaí; total phenolics (1), nonanthocyanin phenolics (2), and total anthocyanins (3). In vitro, fraction 2 moderately inhibited parasite growth in chloroquine-sensitive (HB3) and multiresistant (Dd2) Plasmodium falciparum strains, while none of the fractions was toxic to noncancer cells. Despite the limited activity in vitro, the oral treatment with 20 mg/kg of fraction 1 reduced parasitemia by 89.4% in Plasmodium chabaudi-infected mice and prolonged survival. Contrasting in vitro and in vivo activities of 1 suggest key antiplasmodial roles for polyphenol metabolites rather than the fraction itself. Finally, we performed haploinsufficiency chemical genomic profiling (HIP) utilizing heterozygous Saccharomyces cerevisiae deletion mutants to identify molecular mechanisms of açaí fractions. HIP results indicate proteostasis as the main cellular pathway affected by fraction 2. These results open avenues to develop açaí polyphenols as potential new antimalarial candidates.
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| 5. |
- Garre, Elena, 1978, et al.
(författare)
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The Lsm1-7/Pat1 complex binds to stress-activated mRNAs and modulates the response to hyperosmotic shock.
- 2018
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Ingår i: PLoS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 14:7
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Tidskriftsartikel (refereegranskat)abstract
- RNA-binding proteins (RBPs) establish the cellular fate of a transcript, but an understanding of these processes has been limited by a lack of identified specific interactions between RNA and protein molecules. Using MS2 RNA tagging, we have purified proteins associated with individual mRNA species induced by osmotic stress, STL1 and GPD1. We found members of the Lsm1-7/Pat1 RBP complex to preferentially bind these mRNAs, relative to the non-stress induced mRNAs, HYP2 and ASH1. To assess the functional importance, we mutated components of the Lsm1-7/Pat1 RBP complex and analyzed the impact on expression of osmostress gene products. We observed a defect in global translation inhibition under osmotic stress in pat1 and lsm1 mutants, which correlated with an abnormally high association of both non-stress and stress-induced mRNAs to translationally active polysomes. Additionally, for stress-induced proteins normally triggered only by moderate or high osmostress, in the mutants the protein levels rose high already at weak hyperosmosis. Analysis of ribosome passage on mRNAs through co-translational decay from the 5' end (5P-Seq) showed increased ribosome accumulation in lsm1 and pat1 mutants upstream of the start codon. This effect was particularly strong for mRNAs induced under osmostress. Thus, our results indicate that, in addition to its role in degradation, the Lsm1-7/Pat1 complex acts as a selective translational repressor, having stronger effect over the translation initiation of heavily expressed mRNAs. Binding of the Lsm1-7/Pat1p complex to osmostress-induced mRNAs mitigates their translation, suppressing it in conditions of weak or no stress, and avoiding a hyperresponse when triggered.
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| 6. |
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| 7. |
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| 8. |
- Hu, Xiao-Lei, et al.
(författare)
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Rehabilitering efter stroke - Socialstyrelsens strokeriktlinjer medför nya utmaningar
- 2018
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Ingår i: Läkartidningen. - 0023-7205 .- 1652-7518. ; 115:51-52
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Tidskriftsartikel (refereegranskat)abstract
- Stroke rehabilitation has often been based on tradition instead of evidence-based methods in the clinical practice. The recently updated Swedish national stroke guidelines have emphasized the amount of evidence-based stroke rehabilitation that is expected to be implemented in clinical practice. The most important recommendations in regarding stroke rehabilitation are the early support discharge, a structured follow-up at the subacute stage for identifying unmet rehabilitation needs and high intensity task-specific training from early to chronic phases. Meanwhile, we have to use the resource in a most cost-effective ways, such as a newly developed Rehab-Compass, group education for patients and caregivers ("stroke school") and sufficient number of employees of different occupational groups including rehab-assistants, to provide stroke survivors more evidence-based rehabilitation. These inputs will not only improve quality of stroke care but also save the medical and community resource in the near future.
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| 9. |
- Knutsen, Jon Halvor, et al.
(författare)
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Stress-induced inhibition of translation independently of eIF2α phosphorylation
- 2015
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Ingår i: Journal of Cell Science. - : The Company of Biologists. - 0021-9533 .- 1477-9137. ; 128:23, s. 4420-4427
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Tidskriftsartikel (refereegranskat)abstract
- Exposure of fission yeast cells to ultraviolet (UV) light leads to inhibition of translation and phosphorylation of the eukaryotic initiation factor-2α (eIF2α). This phosphorylation is a common response to stress in all eukaryotes. It leads to inhibition of translation at the initiation stage and is thought to be the main reason why stressed cells dramatically reduce protein synthesis. Phosphorylation of eIF2α has been taken as a readout for downregulation of translation, but the role of eIF2α phosphorylation in the downregulation of general translation has not been much investigated. We show here that UVinduced global inhibition of translation in fission yeast cells is independent of eIF2α phosphorylation and the eIF2α kinase general control nonderepressible-2 protein (Gcn2). Also, in budding yeast and mammalian cells, the UV-induced translational depression is largely independent of GCN2 and eIF2α phosphorylation. Furthermore, exposure of fission yeast cells to oxidative stress generated by hydrogen peroxide induced an inhibition of translation that is also independent of Gcn2 and of eIF2α phosphorylation. Our findings show that stress-induced translational inhibition occurs through an unknown mechanism that is likely to be conserved through evolution.
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| 10. |
- Li, Tianlu, 1988, et al.
(författare)
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The mRNA cap-binding protein Cbc1 is required for high and timely expression of genes by promoting the accumulation of gene-specific activators at promoters
- 2016
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Ingår i: Biochimica et Biophysica Acta. Gene Regulatory Mechanisms. - : Elsevier BV. - 1874-9399 .- 1876-4320. ; 1859:2, s. 405-419
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Tidskriftsartikel (refereegranskat)abstract
- The highly conserved Saccharomyces cerevisiae cap-binding protein Cbc1/Sto1 binds mRNA co-transcriptionally and acts as a key coordinator of mRNA fate. Recently, Cbc1 has also been implicated in transcription elongation and pre-initiation complex (PIC) formation. Previously, we described Cbc1 to be required for cell growth under osmotic stress and to mediate osmostress-induced translation reprogramming. Here, we observe delayed global transcription kinetics in cbc1Δ during osmotic stress that correlates with delayed recruitment of TBP and RNA polymerase II to osmo-induced promoters. Interestingly, we detect an interaction between Cbc1 and the MAPK Hog1,which controls most gene expression changes during osmostress, and observe that deletion of CBC1 delays the accumulation of the activator complex Hot1–Hog1 at osmostress promoters. Additionally, CBC1 deletion specifically reduces transcription rates of highly transcribed genes under non-stress conditions, such as ribosomal protein (RP) genes, while having low impact on transcription of weakly expressed genes. For RP genes, we show that recruitment of the specific activator Rap1, and subsequently TBP, to promoters is Cbc1-dependent. Altogether, our results indicate that binding of Cbc1 to the cappedmRNAs is necessary for the accumulation of specific activators as well as PIC components at the promoters of genes whose expression requires high and rapid transcription.
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| 11. |
- Marco, Maugeri, 1983, et al.
(författare)
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Linkage between endosomal escape of LNP-mRNA and loading into EVs for transport to other cells
- 2019
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- RNA-based therapeutics hold great promise for treating diseases and lipid nanoparticles (LNPs) represent the most advanced platform for RNA delivery. However, the fate of the LNP-mRNA after endosome-engulfing and escape from the autophagy-lysosomal pathway remains unclear. To investigate this, mRNA (encoding human erythropoietin) was delivered to cells using LNPs, which shows, for the first time, a link between LNP-mRNA endocytosis and its packaging into extracellular vesicles (endo-EVs: secreted after the endocytosis of LNP-mRNA). Endosomal escape of LNP-mRNA is dependent on the molar ratios between ionizable lipids and mRNA nucleotides. Our results show that fractions of ionizable lipids and mRNA (1:1 molar ratio of hEPO mRNA nucleotides:ionizable lipids) of endocytosed LNPs were detected in endo-EVs. Importantly, these EVs can protect the exogenous mRNA during in vivo delivery to produce human protein in mice, detected in plasma and organs. Compared to LNPs, endo-EVs cause lower expression of inflammatory cytokines.
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| 12. |
- Statello, Luisa, et al.
(författare)
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Identification of RNA-binding proteins in exosomes capable of interacting with different types of RNA: RBP-facilitated transport of RNAs into exosomes.
- 2018
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Ingår i: PLoS One. - : Public Library of Science (PLoS). - 1932-6203. ; 13:4
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Tidskriftsartikel (refereegranskat)abstract
- The RNA that is packaged into exosomes is termed as exosomal-shuttle RNA (esRNA); however, the players, which take this subset of RNA (esRNA) into exosomes, remain largely unknown. We hypothesized that RNA binding proteins (RBPs) could serve as key players in this mechanism, by making complexes with RNAs and transporting them into exosomes during the biosynthesis of exosomes. Here, we demonstrate the presence of 30 RBPs in exosomes that were shown to form RNA-RBP complexes with both cellular RNA and exosomal-RNA species. To assess the involvement of these RBPs in RNA-transfer into exosomes, the gene transcripts encoding six of the proteins identified in exosomes (HSP90AB1, XPO5, hnRNPH1, hnRNPM, hnRNPA2B1, and MVP) were silenced by siRNA and subsequent effect on esRNA was assessed. A significant reduction of total esRNA was observed by post-transcriptional silencing of MVP, compared to other RBPs. Furthermore, to confirm the binding of MVP with esRNA, a biotinylated-MVP was transiently expressed in HEK293F cells. Higher levels of esRNA were recovered from MVP that was eluted from exosomes of transfected cells, as compared to those of non-transfected cells. Our data indicate that these RBPs could end up in exosomes together with RNA molecules in the form of RNA-ribonucleoprotein complexes, which could be important for the transport of RNAs into exosomes and the maintenance of RNAs inside exosomes. This type of maintenance may favor the shuttling of RNAs from exosomes to recipient cells in the form of stable complexes.
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