| 1. |
- Arora, Teresa, et al.
(författare)
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A systematic review and meta-analysis to assess the relationship between sleep duration/quality, mental toughness and resilience amongst healthy individuals
- 2022
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Ingår i: Sleep Medicine Reviews. - : Elsevier. - 1087-0792 .- 1532-2955. ; 62
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Forskningsöversikt (refereegranskat)abstract
- The majority of sleep research has focused on deleterious health outcomes, with little attention to positive sequels. A systematic review of the literature regarding sleep duration and/or sleep quality in relation to mental toughness and resilience amongst non-clinical, healthy populations was completed. Eight databases and selected sources for grey literature were searched from their inception to April 2021. A total of 1925 unique records (1898 from the database search and 27 from grey sources) were identified and screened against the pre-set inclusion and exclusion criteria. Of these, 68 studies were eligible and 63 were included in the meta-analysis. Pooled results indicated a weak, positive correlation between sleep duration and resilience (r = 0.11, p < 0.001), and sleep quality (r = 0.27, p < 0.001). The pooled correlation was slightly attenuated for prospective studies pertaining to sleep quality and resilience (r = 0.18, p < 0.001). We found evidence of high publication bias for studies that explored the relationship between sleep quality and resilience. Sleep and resilience are positively correlated but additional research is needed to verify the direct relationship through carefully designed, prospective studies that capture both subjective and objective sleep estimates. For a more comprehensive understanding, complementary reviews that explore the sleep-resilience association are needed for clinical populations, and those who have suffered extreme hardship.
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| 2. |
- Arora, Teresa, et al.
(författare)
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The prevalence of psychological consequences of COVID-19 : A systematic review and meta-analysis of observational studies
- 2022
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Ingår i: Journal of Health Psychology. - : Sage Publications. - 1359-1053 .- 1461-7277. ; 27:4, s. 805-824
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Forskningsöversikt (refereegranskat)abstract
- A systematic review and a meta-analysis were conducted to examine the overall prevalence of psychological health outcomes during COVID-19. Seven databases were systematically searched to include studies reporting on at least one psychological outcome. The pooled prevalence of primary psychological outcomes was 26% (95%CI: 21-32). Pooled prevalence for symptoms of PTSD was 33% (0-86), anxiety 28% (21-36), stress 27% (14-43), and depression 22% (13-33). The prevalence of psychological outcomes was similar in healthcare workers and in the general population (34% [24-44] and 33% [27-40] respectively). High prevalence figures support the importance of ensuring adequate provision of resources for mental health.
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| 3. |
- Cava, Felipe, et al.
(författare)
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Distinct pathways for modification of the bacterial cell wall by non-canonical D-amino acids
- 2011
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Ingår i: EMBO Journal. - : Wiley. - 0261-4189 .- 1460-2075. ; 30:16, s. 3442-3453
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Tidskriftsartikel (refereegranskat)abstract
- Production of non-canonical D-amino acids (NCDAAs) in stationary phase promotes remodelling of peptidoglycan (PG), the polymer that comprises the bacterial cell wall. Impairment of NCDAAs production leads to excessive accumulation of PG and hypersensitivity to osmotic shock; however, the mechanistic bases for these phenotypes were not previously determined. Here, we show that incorporation of NCDAAs into PG is a critical means by which NCDAAs control PG abundance and strength. We identified and reconstituted in vitro two (of at least three) distinct processes that mediate NCDAA incorporation. Diverse bacterial phyla incorporate NCDAAs into their cell walls, either through periplasmic editing of the mature PG or via incorporation into PG precursor subunits in the cytosol. Production of NCDAAs in Vibrio cholerae requires the stress response sigma factor RpoS, suggesting that NCDAAs may aid bacteria in responding to varied environmental challenges. The widespread capacity of diverse bacteria, including non-producers, to incorporate NCDAAs suggests that these amino acids may serve as both autocrine- and paracrine-like regulators of chemical and physical properties of the cell wall in microbial communities.
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| 4. |
- Cava, Felipe, et al.
(författare)
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Emerging knowledge of regulatory roles of D-amino acids in bacteria
- 2011
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Ingår i: Cellular and Molecular Life Sciences (CMLS). - : Springer Science and Business Media LLC. - 1420-682X .- 1420-9071. ; 68:5, s. 817-831
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Tidskriftsartikel (refereegranskat)abstract
- The D-enantiomers of amino acids have been thought to have relatively minor functions in biological processes. While L-amino acids clearly predominate in nature, D-amino acids are sometimes found in proteins that are not synthesized by ribosomes, and D-Ala and D-Glu are routinely found in the peptidoglycan cell wall of bacteria. Here, we review recent findings showing that D-amino acids have previously unappreciated regulatory roles in the bacterial kingdom. Many diverse bacterial phyla synthesize and release D-amino acids, including D-Met and D-Leu, which were not previously known to be made. These noncanonical D-amino acids regulate cell wall remodeling in stationary phase and cause biofilm dispersal in aging bacterial communities. Elucidating the mechanisms by which D-amino acids govern cell wall remodeling and biofilm disassembly will undoubtedly reveal new paradigms for understanding how extracytoplasmic processes are regulated as well as lead to development of novel therapeutics.
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| 5. |
- Dörr, Tobias, et al.
(författare)
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A novel peptidoglycan binding protein crucial for PBP1A-mediated cell wall biogenesis in Vibrio cholerae
- 2014
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Ingår i: PLOS Genetics. - : Public library science. - 1553-7390 .- 1553-7404. ; 10:6, s. e1004433-
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Tidskriftsartikel (refereegranskat)abstract
- The bacterial cell wall, which is comprised of a mesh of polysaccharide strands crosslinked via peptide bridges (peptidoglycan, PG), is critical for maintenance of cell shape and survival. PG assembly is mediated by a variety of Penicillin Binding Proteins (PBP) whose fundamental activities have been characterized in great detail; however, there is limited knowledge of the factors that modulate their activities in different environments or growth phases. In Vibrio cholerae, the cause of cholera, PG synthesis during the transition into stationary phase is primarily mediated by the bifunctional enzyme PBP1A. Here, we screened an ordered V. cholerae transposon library for mutants that are sensitive to growth inhibition by non-canonical D-amino acids (DAA), which prevent growth and maintenance of cell shape in PBP1A-deficient V. cholerae. In addition to PBP1A and its lipoprotein activator LpoA, we found that CsiV, a small periplasmic protein with no previously described function, is essential for growth in the presence of DAA. Deletion of csiV, like deletion of lpoA or the PBP1A-encoding gene mrcA, causes cells to lose their rod shape in the presence of DAA or the beta-lactam antibiotic cefsulodin, and all three mutations are synthetically lethal with deletion of mrcB, which encodes PBP1B, V. cholerae's second key bifunctional PBP. CsiV interacts with LpoA and PG but apparently not with PBP1A, supporting the hypothesis that CsiV promotes LpoA's role as an activator of PBP1A, and thereby modulates V. cholerae PG biogenesis. Finally, the requirement for CsiV in PBP1A-mediated growth of V. cholerae can be overcome either by augmenting PG synthesis or by reducing PG degradation, thereby highlighting the importance of balancing these two processes for bacterial survival.
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| 6. |
- Dörr, Tobias, et al.
(författare)
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Differential Requirement for PBP1a and PBP1b in In Vivo and In Vitro Fitness of Vibrio cholerae
- 2014
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Ingår i: Infection and Immunity. - 0019-9567 .- 1098-5522. ; 82:5, s. 2115-2124
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the roles of the Vibrio cholerae high-molecular-weight bifunctional penicillin binding proteins, PBP1a and PBP1b, in the fitness of this enteric pathogen. Using a screen for synthetic lethality, we found that the V. cholerae PBP1a and PBP1b proteins, like their Escherichia coli homologues, are each essential in the absence of the other and in the absence of the other's putative activator, the outer membrane lipoproteins LpoA and LpoB, respectively. Comparative analyses of V. cholerae mutants suggest that PBP1a/LpoA of V. cholerae play a more prominent role in generating and/or maintaining the pathogen's cell wall than PBP1b/LpoB.V. cholerae lacking PBP1b or LpoB exhibited wild-type growth under all conditions tested. In contrast, V. cholerae lacking PBP1a or LpoA exhibited growth deficiencies in minimal medium, in the presence of deoxycholate and bile, and in competition assays with wild-type cells both in vitro and in the infant mouse small intestine. PBP1a pathway mutants are particularly impaired in stationary phase, which renders them sensitive to a product(s) present in supernatants from stationary-phase wild-type cells. The marked competitive defect of the PBP1a pathway mutants in vivo was largely absent when exponential-phase cells rather than stationary-phase cells were used to inoculate suckling mice. Thus, at least for V. cholerae PBP1a pathway mutants, the growth phase of the inoculum is a key modulator of infectivity.
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| 7. |
- Dörr, Tobias, et al.
(författare)
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Substrate specificity of an elongation-specific peptidoglycan endopeptidase and its implications for cell wall architecture and growth of Vibrio cholerae
- 2013
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Ingår i: Molecular Microbiology. - : Wiley. - 0950-382X .- 1365-2958. ; 89:5, s. 949-962
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Tidskriftsartikel (refereegranskat)abstract
- The bacterial cell wall consists of peptidoglycan (PG), a sturdy mesh of glycan strands cross-linked by short peptides. This rigid structure constrains cell shape and size, yet is sufficiently dynamic to accommodate insertion of newly synthesized PG, which was long hypothesized, and recently demonstrated, to require cleavage of the covalent peptide cross-links that couple previously inserted material. Here, we identify several genes in Vibrio cholerae that collectively are required for growth - particularly elongation - of this pathogen. V. cholerae encodes three putative periplasmic proteins, here denoted ShyA, ShyB, and ShyC, that contain both PG binding and M23 family peptidase domains. While none is essential individually, the absence of both ShyA and ShyC results in synthetic lethality, while the absence of ShyA and ShyB causes a significant growth deficiency. ShyA is a D,d-endopeptidase able to cleave most peptide chain cross-links in V. cholerae's PG. PG from a ∆shyA mutant has decreased average chain length, suggesting that ShyA may promote removal of short PG strands. Unexpectedly, ShyA has little activity against muropeptides containing pentapeptides, which typically characterize newly synthesized material. ShyA's substrate-dependent activity may contribute to selection of cleavage sites in PG, whose implications for the process of side-wall growth are discussed.
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| 8. |
- Lam, Hubert, et al.
(författare)
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D-amino acids govern stationary phase cell wall remodeling in bacteria
- 2009
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 325:5947, s. 1552-1555
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Tidskriftsartikel (refereegranskat)abstract
- In all known organisms, amino acids are predominantly thought to be synthesized and used as their L-enantiomers. Here, we found that bacteria produce diverse D-amino acids as well, which accumulate at millimolar concentrations in supernatants of stationary phase cultures. In Vibrio cholerae, a dedicated racemase produced D-Met and D-Leu, whereas Bacillus subtilis generated D-Tyr and D-Phe. These unusual D-amino acids appear to modulate synthesis of peptidoglycan, a strong and elastic polymer that serves as the stress-bearing component of the bacterial cell wall. D-Amino acids influenced peptidoglycan composition, amount, and strength, both by means of their incorporation into the polymer and by regulating enzymes that synthesize and modify it. Thus, synthesis of D-amino acids may be a common strategy for bacteria to adapt to changing environmental conditions.
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| 9. |
- Xia, Xiaoyan, et al.
(författare)
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Effect of a two-stage intervention package on the cesarean section rate in Guangzhou, China: A before-and-after study.
- 2019
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Ingår i: PLoS medicine. - : Public Library of Science (PLoS). - 1549-1676. ; 16:7
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Tidskriftsartikel (refereegranskat)abstract
- The cesarean section (CS) rate has risen globally during the last two decades. Effective and feasible strategies are needed to reduce it. The aim of this study was to assess the CS rate change after a two-stage intervention package that was designed to reduce the overall CS rate in Guangzhou, China.This intervention package was implemented by the Health Commission of Guangzhou Municipality in 2 stages (October 2010-September 2014 and October 2014-December 2016) and included programs for population health education, skills training for healthcare professionals, equipment and technical support for local healthcare facilities, and capacity building for the maternal near-miss care system. A retrospective repeated cross-sectional study was conducted to evaluate influences of the intervention on CS rates. A pre-intervention period from January 2008 to September 2010 served as the baseline. The primary outcome was the CS rate, and the secondary outcomes included maternal mortality ratio (MMR) and perinatal mortality rate (PMR), all obtained from the Guangzhou Perinatal Health Care and Delivery Surveillance System (GPHCDSS). The Cochran-Armitage test was used to examine the trends of the overall CS rate, MMR, and PMR across different stages. Segmented linear regression analysis was used to assess the change of the CS rate over the intervention period. A total of 1,921,932 records of births and 108 monthly CS rates from 2008 to 2016 were analyzed. The monthly CS rate declined across the intervention stages (Z = 75.067, p < 0.001), with an average rate of 42.4% at baseline, 39.8% at Stage 1, and 35.0% at Stage 2. The CS rate declined substantially among nulliparous women who delivered term singletons, with an accelerating decreasing trend observed across Stage 1 and Stage 2 (the difference in slopes: -0.09 [95% CI -0.16 to -0.02] between Stage 1 and baseline, p = 0.014; -0.11 [95% CI -0.20 to -0.02] between Stage 1 and Stage 2, p = 0.017). The CS rate in the remaining population increased during baseline and Stage 1 and subsequently decreased during Stage 2. The sensitivity analysis suggested no immediate impact of the universal two-child policy on the trend of the CS rate. The MMR (Z = -4.368, p < 0.001) and PMR (Z = -13.142, p < 0.001) declined by stage over the intervention period. One of the main limitations of the study is the lack of a parallel control group. Moreover, the influence of temporal changes in the study population on the CS rate was unknown. Given the observational nature of the present study, causality cannot be confirmed.Apparent decline in the overall CS rate was observed in Guangzhou, China, after the implementation of a two-stage intervention package. The decline was most evident among nulliparous women who delivered term singletons. Despite some limitations for causal inference, Guangzhou's experience in controlling the CS rate by implementing composite interventions with public health education and perinatal healthcare service improvement could have implications for other similar areas with high rates of CS.
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