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- 2019
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Arndt, D. S., et al.
(författare)
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STATE OF THE CLIMATE IN 2017
- 2018
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Ingår i: Bulletin of The American Meteorological Society - (BAMS). - : American Meteorological Society. - 0003-0007 .- 1520-0477. ; 99:8, s. S1-S310
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Forskningsöversikt (refereegranskat)
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| 3. |
- Shi, Lei, 1981, et al.
(författare)
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Evolutionary Analysis of the Bacillus subtilis Genome Reveals New Genes Involved in Sporulation
- 2020
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Ingår i: Molecular biology and evolution. - : Oxford University Press. - 0737-4038 .- 1537-1719. ; 37:6, s. 1667-1678
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Tidskriftsartikel (refereegranskat)abstract
- Bacilli can form dormant, highly resistant, and metabolically inactive spores to cope with extreme environmental challenges. In this study, we examined the evolutionary age of Bacillus subtilis sporulation genes using the approach known as genomic phylostratigraphy. We found that B. subtilis sporulation genes cluster in several groups that emerged at distant evolutionary time-points, suggesting that the sporulation process underwent several stages of expansion. Next, we asked whether such evolutionary stratification of the genome could be used to predict involvement in sporulation of presently uncharacterized genes (y-genes). We individually inactivated a representative sample of uncharacterized genes that arose during the same evolutionary periods as the known sporulation genes and tested the resulting strains for sporulation phenotypes. Sporulation was significantly affected in 16 out of 37 (43%) tested strains. In addition to expanding the knowledge base on B. subtilis sporulation, our findings suggest that evolutionary age could be used to help with genome mining.
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| 4. |
- Bonne Kohler, Julie, et al.
(författare)
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Importance of protein Ser/Thr/Tyr phosphorylation for bacterial pathogenesis
- 2020
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Ingår i: FEBS Letters. - : Wiley. - 1873-3468 .- 0014-5793. ; 594:15, s. 2339-2369
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Forskningsöversikt (refereegranskat)abstract
- Protein phosphorylation regulates a large variety of biological processes in all living cells. In pathogenic bacteria, the study of serine, threonine, and tyrosine (Ser/Thr/Tyr) phosphorylation has shed light on the course of infectious diseases, from adherence to host cells to pathogen virulence, replication, and persistence. Mass spectrometry (MS)-based phosphoproteomics has provided global maps of Ser/Thr/Tyr phosphosites in bacterial pathogens. Despite recent developments, a quantitative and dynamic view of phosphorylation events that occur during bacterial pathogenesis is currently lacking. Temporal, spatial, and subpopulation resolution of phosphorylation data is required to identify key regulatory nodes underlying bacterial pathogenesis. Herein, we discuss how technological improvements in sample handling, MS instrumentation, data processing, and machine learning should improve bacterial phosphoproteomic datasets and the information extracted from them. Such information is expected to significantly extend the current knowledge of Ser/Thr/Tyr phosphorylation in pathogenic bacteria and should ultimately contribute to the design of novel strategies to combat bacterial infections.
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| 5. |
- Chen, Xin, 1980, et al.
(författare)
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Graphene Oxide Attenuates Toxicity of Amyloid-β Aggregates in Yeast by Promoting Disassembly and Boosting Cellular Stress Response
- 2023
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Ingår i: Advanced Functional Materials. - 1616-3028 .- 1616-301X. ; 33:45
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Tidskriftsartikel (refereegranskat)abstract
- Alzheimer's disease (AD) is the most prevalent neurodegenerative disease, with the aggregation of misfolded amyloid-β (Aβ) peptides in the brain being one of its histopathological hallmarks. Recently, graphene oxide (GO) nanoflakes have attracted significant attention in biomedical areas due to their capacity of suppressing Aβ aggregation in vitro. The mechanism of this beneficial effect has not been fully understood in vivo. Herein, the impact of GO on intracellular Aβ42 aggregates and cytotoxicity is investigated using yeast Saccharomyces cerevisiae as the model organism. This study finds that GO nanoflakes can effectively penetrate yeast cells and reduce Aβ42 toxicity. Combination of proteomics data and follow-up experiments show that GO treatment alters cellular metabolism to increases cellular resistance to misfolded protein stress and oxidative stress, and reduces amounts of intracellular Aβ42 oligomers. Additionally, GO treatment also reduces HTT103QP toxicity in the Huntington's disease (HD) yeast model. The findings offer insights for rationally designing GO nanoflakes-based therapies for attenuating cytotoxicity of Aβ42, and potentially of other misfolded proteins involved in neurodegenerative pathology.
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| 6. |
- Derouiche, Abderahmane, 1980, et al.
(författare)
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Bacillus subtilisSalA is a phosphorylation-dependent transcription regulator that represses scoC and activates the production of the exoprotease AprE
- 2015
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Ingår i: Molecular Microbiology. - : Wiley. - 1365-2958 .- 0950-382X. ; 97:6, s. 1195-1208
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Tidskriftsartikel (refereegranskat)abstract
- Bacillus subtilisMrp family protein SalA has been shown to indirectly promote the production of the exoprotease AprE by inhibiting the expression of scoC, which codes for a repressor of aprE. The exact mechanism by which SalA influences scoC expression has not been clarified previously. We demonstrate that SalA possesses a DNA-binding domain (residues 1-60), which binds to the promoter region of scoC. The binding of SalA to its target DNA depends on the presence of ATP and is stimulated by phosphorylation of SalA at tyrosine 327. The B.subtilis protein-tyrosine kinase PtkA interacts specifically with the C-terminal domain of SalAin vivo and in vitro and is responsible for activating its DNA binding via phosphorylation of tyrosine 327. In vivo, a mutant mimicking phosphorylation of SalA (SalA Y327E) exhibited a strong repression of scoC and consequently overproduction of AprE. By contrast, the non-phosphorylatable SalA Y327F and the ΔptkA exhibited the opposite effect, stronger expression of scoC and lower production of the exoprotease. Interestingly, both SalA and PtkA contain the same ATP-binding Walker domain and have thus presumably arisen from the common ancestral protein. Their regulatory interplay seems to be conserved in other bacteria.
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| 7. |
- Derouiche, Abderahmane, 1980, et al.
(författare)
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Evolution and tinkering: what do a protein kinase, a transcriptional regulator and chromosome segregation/cell division proteins have in common?
- 2016
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Ingår i: Current Genetics. - : Springer Science and Business Media LLC. - 0172-8083 .- 1432-0983. ; 62:1, s. 67-70
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Forskningsöversikt (refereegranskat)abstract
- In this study, we focus on functional interactions among multi-domain proteins which share a common evolutionary origin. The examples we develop are four Bacillus subtilis proteins, which all possess an ATP-binding Walker motif: the bacterial tyrosine kinase (BY-kinase) PtkA, the chromosome segregation protein Soj (ParA), the cell division protein MinD and a transcription regulator SalA. These proteins have arisen via duplication of the ancestral ATP-binding domain, which has undergone fusions with other functional domains in the process of divergent evolution. We point out that these four proteins, despite having very different physiological roles, engage in an unusually high number of binary functional interactions. Namely, MinD attracts Soj and PtkA to the cell pole, and in addition, activates the kinase function of PtkA. SalA also activates the kinase function of PtkA, and it gets phosphorylated by PtkA as well. The consequence of this phosphorylation is the activation of SalA as a transcriptional repressor. We hypothesize that these functional interactions remain preserved during divergent evolution and represent a constraint on the process of evolutionary "tinkering", brought about by fusions of different functional domains.
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| 8. |
- Derouiche, Abderahmane, 1980, et al.
(författare)
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Substrate Specificity of the Bacillus subtilis BY-Kinase PtkA Is Controlled by Alternative Activators: TkmA and SalA
- 2016
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Ingår i: Frontiers in Microbiology. - : Frontiers Media SA. - 1664-302X. ; 7:SEP
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Tidskriftsartikel (refereegranskat)abstract
- Bacterial protein-tyrosine kinases (BY-kinases) are known to regulate different aspects of bacterial physiology, by phosphorylating cellular protein substrates. Physiological cues that trigger BY-kinases activity are largely unexplored. In Proteobacteria, BY-kinases contain a cytosol-exposed catalytic domain and a transmembrane activator domain in a single polypeptide chain. In Firrnicutes, the BY-kinase catalytic domain and the transmembrane activator domain exist as separate polypeptides. We have previously speculated that this architecture might enable the Firmicutes BY-kinases to interact with alternative activators, and thus account for the observed ability of these kinases to phosphorylate several distinct classes of protein substrates. Here, we present experimental evidence that supports this hypothesis. We focus on the model Firmicute-type BY-kinase PtkA from Bacillus subtilis, known to phosphorylate several different protein substrates. We demonstrate that the transcriptional regulator SaIA, hitherto known as a substrate of PtkA, can also act as a PtkA activator. In doing so, SaIA competes with the canonical PtkA activator, TkmA. Our results suggest that the respective interactions of SaIA and TkmA with PtkA favor phosphorylation of different protein substrates in vivo and in vitro. This observation may contribute to explaining how specificity is established in the seemingly promiscuous interactions of BY-kinases with their cellular substrates.
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| 9. |
- Garcia-Garcia, T., et al.
(författare)
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Role of Protein Phosphorylation in the Regulation of Cell Cycle and DNA-Related Processes in Bacteria
- 2016
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Ingår i: Frontiers in Microbiology. - : Frontiers Media SA. - 1664-302X. ; 7:FEB
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Forskningsöversikt (refereegranskat)abstract
- In all living organisms, the phosphorylation of proteins modulates various aspects of their functionalities. In eukaryotes, protein phosphorylation plays a key role in cell signaling, gene expression, and differentiation. Protein phosphorylation is also involved in the global control of DNA replication during the cell cycle, as well as in the mechanisms that cope with stress-induced replication blocks. Similar to eukaryotes, bacteria use Hanks-type kinases and phosphatases for signal transduction, and protein phosphorylation is involved in numerous cellular processes. However, it remains unclear whether protein phosphorylation in bacteria can also regulate the activity of proteins involved in DNA-mediated processes such as DNA replication or repair. Accumulating evidence supported by functional and biochemical studies suggests that phospho-regulatory mechanisms also take place during the bacterial cell cycle. Recent phosphoproteomics and interactomics studies identified numerous phosphoproteins involved in various aspect of DNA metabolism strongly supporting the existence of such level of regulation in bacteria. Similar to eukaryotes, bacterial scaffolding-like proteins emerged as platforms for kinase activation and signaling. This review reports the current knowledge on the phosphorylation of proteins involved in the maintenance of genome integrity and the regulation of cell cycle in bacteria that reveals surprising similarities to eukaryotes.
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| 10. |
- Ivashina, Marianna, 1975, et al.
(författare)
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A 1-D Steerable Beam Slotted Waveguide Antenna Employing Non-Conventional Aperiodic Array Architecture for mm-wave Line-Of-Sight MIMO
- 2019
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Ingår i: 2019 IEEE International Conference on Microwaves, Antennas, Communications and Electronic Systems, COMCAS 2019. - 9781538695494
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Konferensbidrag (refereegranskat)abstract
- A 9 x 9 line-of-sight MIMO test setup is presented. The slotted waveguide (WG) antenna as designed for this setup achieves low side-lobe levels (SLLs) in all planes for multiple scanned beams, while minimizing the loss in antenna efficiency and bandwidth limitations. The aperiodic arrangement of several parallel ridge WGs in the E-plane each with a different number of equally-spaced and equally-excited radiating slots along the H-plane, and each possibly integrated with its own TX/Rx module has been optimized through a Compressive Sensing approach. This results in 160 slots organized in 16 columns offering 29 dBi peak gain at a 27.5-31.5 GHz band with a 10 scan range in the E-plane for the ETSI Class-II-compliant beams. The measurements of 12 identically beamformed antenna prototypes for the broadside beam confirm the expected high antenna efficiency (70-90%), and low input impedance mismatch over the entire operating bandwidth.
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