scholarly journals The lolB gene in Xanthomonas campestris pv. campestris is required for bacterial attachment, stress tolerance, and virulence

2022 ◽  
Vol 22 (1) ◽  
Author(s):  
Chao-Tsai Liao ◽  
Chih-En Li ◽  
Hsiao-Ching Chang ◽  
Chien-Hui Hsu ◽  
Ying-Chuan Chiang ◽  
...  
Keyword(s):  
Stress Tolerance ◽  
Outer Membrane ◽  
Xanthomonas Campestris ◽  
Extracellular Enzymes ◽  
Physiological Role ◽  
Extracellular Enzyme ◽  
Bacterial Attachment ◽  
Expression Of Genes ◽  
Functional Understanding

Abstract Background Xanthomonas campestris pv. campestris (Xcc) is a Gram-negative bacterium that can cause black rot disease in crucifers. The lipoprotein outer membrane localization (Lol) system is involved in the lipoprotein sorting to the outer membrane. Although Xcc has a set of annotated lol genes, there is still little known about the physiological role in this phytopathogen. In this study, we aimed to characterize the role of LolB of Xcc in bacterial attachment, stress tolerance, and virulence. Results To characterize the role of LolB, lolB mutant was constructed and phenotypic evaluation was performed. The lolB mutant revealed reductions in bacterial attachment, extracellular enzyme production, and virulence. Mutation of lolB also resulted in reduced tolerance to a myriad of stresses, including heat and a range of membrane-perturbing agents. Trans-complementation of lolB mutant with intact lolB gene reverted these altered phenotypes to the wild-type levels. From subsequent reporter assay and reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) analysis, the expression of genes that encode the major extracellular enzymes and the stress-related proteins was reduced after lolB mutation. Conclusions The results in this work contribute to the functional understanding of lolB in Xanthomonas for the first time, and provide new insights into the function of lolB in bacteria.

scholarly journals Mutation of the gene encoding a major outer-membrane protein in Xanthomonas campestris pv. campestris causes pleiotropic effects, including loss of pathogenicity

Microbiology ◽  
2010 ◽  
Vol 156 (9) ◽  
pp. 2842-2854 ◽  
Author(s):  
Yih-Yuan Chen ◽  
Chieh-Hao Wu ◽  
Juey-Wen Lin ◽  
Shu-Fen Weng ◽  
Yi-Hsiung Tseng
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Xanthomonas Campestris ◽  
Extracellular Enzymes ◽  
Surface Deformation ◽  
Cell Signalling ◽  
Cell Aggregation ◽  
Major Outer Membrane Protein ◽  
Gene Encoding

Xanthomonas campestris pv. campestris (Xcc) is the phytopathogen that causes black rot in crucifers. The xanthan polysaccharide and extracellular enzymes produced by this organism are virulence factors, the expression of which is upregulated by Clp (CRP-like protein) and DSF (diffusible signal factor), which is synthesized by RpfF. It is also known that biofilm formation/dispersal, regulated by the effect of controlled synthesis of DSF on cell–cell signalling, is required for virulence. Furthermore, a deficiency in DSF causes cell aggregation with concomitant production of a gum-like substance that can be dispersed by addition of DSF or digested by exogenous endo-β-1,4-mannanase expressed by Xcc. In this study, Western blotting of proteins from a mopB mutant (XcMopB) showed Xcc MopB to be the major outer-membrane protein (OMP); Xcc MopB shared over 97 % identity with homologues from other members of Xanthomonas. Similarly to the rpfF mutant, XcMopB formed aggregates with simultaneous production of a gummy substance, but these aggregates could not be dispersed by DSF or endo-β-1,4-mannanase, indicating that different mechanisms were involved in aggregation. In addition, XcMopB showed surface deformation, altered OMP composition, impaired xanthan production, increased sensitivity to stressful conditions including SDS, elevated temperature and changes in pH, reduced adhesion and motility and defects in pathogenesis. The finding that the major OMP is required for pathogenicity is unprecedented in phytopathogenic bacteria.

scholarly journals miR-21 blocks obesity in mice: a potential therapy for humans

2020 ◽  
Author(s):  
Said Lhamyani ◽  
Adriana-Mariel Gentile ◽  
Rosa M. Giráldez-Pérez ◽  
Mónica Feijóo-Cuaresma ◽  
Silvana Yanina Romero-Zerbo ◽  
...  
Keyword(s):  
High Fat Diet ◽  
Drug Targets ◽  
Metabolic Disorders ◽  
Molecular Mechanisms ◽  
Caloric Intake ◽  
Physiological Role ◽  
Expression Of Genes ◽  
Obesity In Mice ◽  
Metabolically Healthy

AbstractmicroRNAs are promising drug targets in obesity and metabolic disorders. miR-21 expression is upregulated in obese white adipose tissue (WAT); however, its physiological role in WAT has not been fully explored. We aimed to dissect the underlying molecular mechanisms of miR-21 in treating obesity, diabetes, and insulin resistance. We demonstrated, in human and mice, that elevated miR-21 expression is associated with metabolically healthy obesity. miR-21 mimic affected the expression of genes associated with adipogenesis, thermogenesis, and browning in 3T3-L1 adipocytes. In addition, it blocked high fat diet-induced weight gain in obese mice, without modifying food intake or physical activity. This was associated with metabolic enhancements, WAT browning and thermogenic programming, and brown AT induction through VEGF-A, p53, and TGFβ1 signaling pathways. Our findings add a novel role of miR-21 in the regulation of obesity and a potential therapy for both obesity and T2D without altering caloric intake and physical activities.

scholarly journals Importance of Bacillithiol in the Oxidative Stress Response of Staphylococcus aureus

2013 ◽  
Vol 82 (1) ◽  
pp. 316-332 ◽  
Author(s):  
Ana C. Posada ◽  
Stacey L. Kolar ◽  
Renata G. Dusi ◽  
Patrice Francois ◽  
Alexandra A. Roberts ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Staphylococcus Aureus ◽  
Physiological Role ◽  
Content Type ◽  
Chromatography Analysis ◽  
Expression Of Genes ◽  
Fold Reduction ◽  
Fosfomycin Resistance ◽  
Microarray Analyses

ABSTRACTInStaphylococcus aureus, the low-molecular-weight thiol called bacillithiol (BSH), together with cognateS-transferases, is believed to be the counterpart to the glutathione system of other organisms. To explore the physiological role of BSH inS. aureus, we constructed mutants with the deletion ofbshA(sa1291), which encodes the glycosyltransferase that catalyzes the first step of BSH biosynthesis, andfosB(sa2124), which encodes a BSH-S-transferase that confers fosfomycin resistance, in severalS. aureusstrains, including clinical isolates. Mutation offosBorbshAcaused a 16- to 60-fold reduction in fosfomycin resistance in theseS. aureusstrains. High-pressure liquid chromatography analysis, which quantified thiol extracts, revealed some variability in the amounts of BSH present acrossS. aureusstrains. Deletion offosBled to a decrease in BSH levels. ThefosBandbshAmutants of strain COL and a USA300 isolate, upon further characterization, were found to be sensitive to H2O2and exhibited decreased NADPH levels compared with those in the isogenic parents. Microarray analyses of COL and the isogenicbshAmutant revealed increased expression of genes involved in staphyloxanthin synthesis in thebshAmutant relative to that in COL under thiol stress conditions. However, thebshAmutant of COL demonstrated decreased survival compared to that of the parent in human whole-blood survival assays; likewise, the naturally BSH-deficient strain SH1000 survived less well than its BSH-producing isogenic counterpart. Thus, the survival ofS. aureusunder oxidative stress is facilitated by BSH, possibly via a FosB-mediated mechanism, independently of its capability to produce staphyloxanthin.

HOXC10 suppresses browning to maintain white adipocyte identity

2021 ◽  
Author(s):  
H. Y. Angeline Tan ◽  
M. F. Michelle Sim ◽  
Shi-Xiong Tan ◽  
Yvonne Ng ◽  
Sin Yee Gan ◽  
...  
Keyword(s):  
Mrna Level ◽  
Physiological Role ◽  
Shotgun Proteomics ◽  
White Adipocyte ◽  
E3 Ligases ◽  
Obesity Epidemic ◽  
Expression Of Genes ◽  
Proteomics Approach ◽  
Adipocyte Development

Promoting beige adipocyte development within white adipose tissue (WAT) is a potential therapeutic approach to staunch the current obesity epidemic. Previously, we identified homeobox-containing transcription factor HOXC10 as a suppressor of browning in subcutaneous WAT. Here, we provide evidence for the physiological role of HOXC10 in regulating WAT thermogenesis. Analysis of an adipose-specific HOXC10 knockout mouse line with no detectable HOXC10 in mature adipocytes revealed spontaneous subcutaneous WAT browning, increased expression of genes involved in browning, increased basal rectal temperature, enhanced cold tolerance and improved glucose homeostasis. These phenotypes were further exacerbated by exposure to cold or a β-adrenergic stimulant. Mechanistically, cold and β-adrenergic exposure led to reduced HOXC10 protein level without affecting its mRNA level. Cold exposure induced PKA-dependent proteasome-mediated degradation of HOXC10 in cultured adipocytes and shotgun proteomics approach identified KCTD 2, 5 and 17 as potential E3 ligases regulating HOXC10 proteasomal degradation. Collectively, these data demonstrate that HOXC10 is a gatekeeper of WAT identity, and targeting HOXC10 could be a plausible therapeutic strategy to unlock WAT thermogenic potentials.

rpfF Mutants of Xanthomonas oryzae pv. oryzae Are Deficient for Virulence and Growth Under Low Iron Conditions

2002 ◽  
Vol 15 (5) ◽  
pp. 463-471 ◽  
Author(s):  
Subhadeep Chatterjee ◽  
Ramesh V. Sonti
Keyword(s):  
Xanthomonas Campestris ◽  
Iron Supplementation ◽  
Extracellular Enzymes ◽  
Phenotypic Expression ◽  
Tetracycline Resistance ◽  
Extracellular Enzyme ◽  
Extracellular Polysaccharide ◽  
Xanthomonas Oryzae ◽  
Uptake System ◽  
Serious Disease

Xanthomonas oryzae pv. oryzae causes bacterial leaf blight, a serious disease of rice. In the related bacterium Xanthomonas campestris pv. campestris, the rpfF gene is involved in production of a diffusible extracellular factor (DSF) that positively regulates synthesis of virulence-associated functions like extracellular polysaccharide (EPS) and extracellular enzymes. Transposon insertions in the rpfF homolog of X. oryzae pv. oryzae are deficient for virulence and production of a DSF but are proficient for EPS and extracellular enzyme production. The rpfF X. oryzae pv. oryzae mutants exhibit an unusual tetracycline susceptibility phenotype in which exogenous iron supplementation is required for phenotypic expression of a tetracycline resistance determinant that is encoded on an introduced plasmid. The rpfF X. oryzae pv. oryzae mutants also overproduce one or more siderophores and exhibit a growth deficiency under low iron conditions as well as in the presence of reducing agents that are expected to promote the conversion of Fe+3 to Fe+2. Exogenous iron supplementation promotes migration of rpfF X. oryzae pv. oryzae mutants in rice leaves. The results suggest that rpfF may be involved in controlling an iron-uptake system of X. oryzae pv. oryzae and that an inability to cope with the conditions of low iron availability in the host may be the reason for the virulence deficiency of the rpfF X. oryzae pv. oryzae mutants.

scholarly journals Phosphorylation of LXRα impacts atherosclerosis regression by modulating monocyte/macrophage trafficking

2018 ◽  
Author(s):  
Elina Shrestha ◽  
Maud Voisin ◽  
Tessa J. Barrett ◽  
Hitoo Nishi ◽  
David J. Cantor ◽  
...  
Keyword(s):  
Cell Movement ◽  
Physiological Role ◽  
Favorable Effect ◽  
Atherosclerotic Plaques ◽  
Rna Seq ◽  
Phosphorylated Form ◽  
Expression Of Genes ◽  
Normal Glucose ◽  
Plaque Regression

AbstractLXRα activation in macrophages enhances regression of atherosclerotic plaques in mice by regulating genes crucial for cholesterol efflux, cell motility and inflammation. Diabetes, however, impairs plaque regression in mice. LXRα is phosphorylated at serine 198 (pS198), which affects the expression of genes controlling inflammation, lipid metabolism and cell movement. We hypothesize that LXRα function is affected by hyperglycemia through changes in LXRα pS198. Indeed, macrophages cultured in diabetes relevant high glucose versus normal glucose display alterations in LXR-dependent gene expression and increased LXRα pS198. We therefore examined the consequence of disrupting LXRα phosphorylation (S196A in mouse LXRα) during regression of atherosclerosis in normal and diabetic mice. We find that phosphorylation deficient LXRα S196A reduces macrophage retention in plaques in diabetes, which is predicted to be anti-atherogenic and enhance plaque regression. However, this favorable effect on regression is masked by increased monocyte infiltration in the plaque attributed to leukocytosis in LXRα S196A mice. RNA-seq of plaque macrophages from diabetic S196A mice shows increased expression of chemotaxis and decreased expression of cell adhesion genes, consistent with reduced macrophage retention by LXRα S196A. Thus, the non-phosphorylated form of LXRα precludes macrophage retention in the plaque. Our study provides the first evidence for a physiological role of LXRα phosphorylation in modulating atherosclerosis regression. Compounds that prevent LXRα phosphorylation or ligands that induce the conformation of non-phosphorylated LXRα may selectively enhance macrophage emigration from atherosclerotic plaques.

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