JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2024
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IF 5.7
Xuemeng Ji,Aiying Shi,Jin Wang,Bowei Zhang,Yaozhong Hu,Huan Lv,Jing Wu,Yi Sun,Jing-Min Liu,Yan Zhang,Shuo Wang
Cronobacter sakazakii is a notorious foodborne opportunistic pathogen, particularly affecting vulnerable populations such as premature infants, and poses significant public health challenges. This study aimed to elucidate the role of the envZ/ompR genes in environmental tolerance, pathogenicity, and protein regulation of C. sakazakii. An envZ/ompR knockout mutant was constructed and assessed for its impact on bacterial growth, virulence, environmental tolerance, and protein regulation. Results demonstrate that deletion of envZ/ompR genes leads to reduced growth rate and attenuated virulence in animal models. Additionally, the knockout strain exhibited compromised environmental tolerance, particularly in desiccation and oxidative stress conditions, along with impaired adhesion and invasion abilities in epithelial cells. Proteomic analysis revealed significant alterations in protein expression and phosphorylation patterns, highlighting potential compensatory mechanisms triggered by gene deletion. Furthermore, investigation into protein deamidation and glucose metabolism uncovered a link between envZ/ompR deletion and energy metabolism dysregulation. Interestingly, the downregulation of MalK and GrxC proteins was identified as contributing factors to altered desiccation tolerance and disrupted redox homeostasis, respectively, providing mechanistic insights into the phenotypic changes observed. Overall, this study enhances understanding of the multifaceted roles of envZ/ompR in C. sakazakii physiology and pathogenesis, shedding light on potential targets for therapeutic intervention and food safety strategies.
研究领域:
微生物学
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食品科学
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分子生物学
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产品关联
DOI
PubMed
高影响因子
PLoS Pathogens
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2024
·Vol. 20
·期 10
·e1012675
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IF 5.5
Lijun Wang,Zhe Wang,Hua Zhang,Qian Jin,Shuaihua Fan,Yanni Liu,Xueting Huang,Jun Guo,Chao Cai,Jing-ren Zhang,Hui Wu
Klebsiella pneumoniae , an emerging multidrug-resistant pathogen, exhibits hypermucoviscosity (HMV) as a critical virulence trait mediated by its capsular polysaccharide (CPS). Recent discoveries have determined acetylation as a significant modification for CPS, although its impact on HMV and virulence was previously unknown. This study elucidates the roles of two enzymes: K lebsiella p neumoniae A cetylated C PS E sterase (KpACE), an esterase that removes acetyl groups from CPS, and WcsU, an acetyltransferase that adds acetyl groups to CPS. KpACE is highly upregulated in an ompR -deficient mutant lacking HMV, and its overexpression consistently reduces HMV and diminishes virulence in a mouse model of pneumonia. The esterase domain-containing KpACE effectively deacetylates model sugar substrates and CPS-K2. Site-directed mutagenesis of the conserved catalytic histidine residue at position 370 significantly reduces its enzymatic activity. This reduction correlates with decreased HMV, affecting key virulence traits including biofilm formation and serum resistance. Similarly, a deficiency in the wcsU gene abolishes CPS acetylation, and reduces HMV and virulence. These results highlight the importance of the delicate balance between CPS acetylation by WcsU and deacetylation by KpACE in regulating the pathogenicity of K . pneumoniae . Understanding this balance provides new insights into the modulation of virulence traits and potential therapeutic targets for combating K . pneumoniae infections.
Klebsiella pneumoniae is an antibiotic-resistant pathogen known for its virulence factor, hypermucoviscosity (HMV), which relies on the production of capsular polysaccharides (CPS). This study highlights the roles of two key enzymes: KpACE, an esterase that removes acetyl groups from CPS, and WcsU, an acetyltransferase that adds acetyl groups to CPS. Overexpression of KpACE reduces HMV and decreases virulence in a mouse pneumonia model by deacetylating CPS. Conversely, a deficiency in the wcsU gene, which is responsible for acetylating CPS, also results in decreased HMV and virulence. The balance between CPS acetylation by WcsU and deacetylation by KpACE is crucial in regulating K . pneumoniae pathogenicity. This balance affects various virulence factors, including biofilm formation and serum resistance, highlighting the importance of CPS acetylation dynamics in the pathogen’s fitness and virulence. Understanding these mechanisms offers insights into potential therapeutic targets to mitigate the virulence and antibiotic resistance of K . pneumoniae .
研究领域:
微生物学
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传染病学
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分子生物学
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致病机制
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DOI
PubMed
高影响因子
FOOD RESEARCH INTERNATIONAL
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2023
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IF 8.1
Juan Xue,Jun Lv,Lanfang Liu,Fangfang Duan,Aiying Shi,Xuemeng Ji,Li Ding
Cronobacter sakazakii ( C. sakazakii ) is a notorious pathogen responsible for infections in infants and newborns, often transmitted through contaminated infant formula. Despite the use of traditional pasteurization methods, which can reduce microbial contamination, there remains a significant risk of pathogenic C. sakazakii surviving due to its exceptional stress tolerance. In our study, we employed a comparative proteomic approach by comparing wild-type strains with gene knockout strains to identify the essential genes crucial for the successful survival of C. sakazakii during desiccation. Our investigation revealed the significance of envZ-ompR , recA , and flhD gene cassettes in contributing to desiccation tolerance in C. sakazakii . Furthermore, through our comparative proteomic profiling, we identified the maltodextrin-binding protein encoded by ESA_03421 as a potential factor influencing dry tolerance. This protein is regulated by EnvZ-OmpR , RecA , and FlhD . Notably, the knockout of ESA_03421 resulted in a 150% greater reduction in Log CFU compared to the wild-type C. sakazakii . Overall, our findings offer valuable insights into the mechanisms underlying C. sakazakii desiccation tolerance and provide potential targets for the development of new antimicrobial strategies aimed at reducing the risk of infections in infants and newborns.
研究领域:
微生物学
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蛋白质组学
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食品安全
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婴儿健康
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产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）