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stress salmonella

José Andrés Medrano-Félix, Cristóbal Chaidez, Kristina D Mena, María Del Socorro Soto-Galindo, Nohelia Castro-Del Campo
Survival of bacterial pathogens in different environments is due, in part, to their ability to form biofilms. Four wild-type Salmonella enterica strains, two Oranienburg and two Saintpaul isolated from river water and animal feces, were tested for biofilm formation at the air-liquid interface under stressful conditions (pH and salinity treatments such as pH 3, NaCl 4.5 w/v; pH 7, NaCl 4.5 w/v; pH 10, NaCl 4.5 w/v; pH 3, Nacl 0.5 w/v; pH 7, NaCl 0.5 w/v; and pH 10, NaCl 0.5 w/v); Salmonella Typhimurium DT104 was used as a control strain...
March 15, 2018: Environmental Monitoring and Assessment
Lal Sangpuii, Sunil Kumar Dixit, Manoj Kumawat, Shekhar Apoorva, Mukesh Kumar, Deepthi Kappala, Tapas Kumar Goswami, Manish Mahawar
By assisting in the proteolysis, disaggregation and refolding of the aggregated proteins, Caseinolytic proteases (Clps) enhance the cellular survival under stress conditions. In the current study, comparative roles of two such Clps, ClpA (involved in proteolysis) and ClpB (involved in protein disaggregation and refolding) in the survival of Salmonella Typhimurium (S. Typhimurium) under different stresses and in virulence have been investigated. clpA and clpB gene deletion mutant strains (∆clpA and ∆clpB) of S...
March 14, 2018: Scientific Reports
Pramod Gavel, Dharm Dev, Hamendra Singh Parmar, Sheetal Bhasin, Apurba K Das
Here, we report the self-assembly of Amoc (9-anthracenemethoxycarbonyl)-capped dipeptides, which self-assemble to form injectable, self-healable and shape-memory hydrogels with inherent antibacterial properties. Amoc-capped dipeptides self-assemble to form nanofibrillar networks, which are established by several spectroscopic and microscopic techniques. The inherent antibacterial properties of hydrogels are evaluated using two Gram-positive Staphylococcus aureus, Bacillus subtilis and three Gram-negative Escherichia coli, Pseudomonas aeruginosa and Salmonella typhi bacteria...
March 14, 2018: ACS Applied Materials & Interfaces
Whittney N Burda, Karen E Brenneman, Amanda Gonzales, Roy Curtiss
The vast majority of live attenuated typhoid vaccines are constructed from the Salmonella enterica serovar Typhi strain Ty2, which is devoid of a functioning alternative sigma factor, RpoS, due to the presence of a frameshift mutation. RpoS is a specialized sigma factor that plays an important role in the general stress response of a number of Gram-negative organisms, including Salmonella . Previous studies have demonstrated that this sigma factor is necessary for survival following exposure to acid, hydrogen peroxide, nutrient-limiting conditions, and starvation...
January 2018: MSphere
Anastasia N Ezemaduka, Yanchun Lv, Yunbiao Wang, Jingbo Xu, Xiujun Li
Small heat shock proteins (sHSPs) are ubiquitous stress proteins that are able to protect the cells against cellular insults from temperature, heavy metal etc. However, the molecular chaperone roles of sHSPs in enhancing growth and adaptation under combined temperature and metal stresses in Escherichia coli cells have been poorly understood. Here, we analyze the function of recombinant AgsA, a small heat shock protein from Salmonella enterica serovar Typhimurium under combined temperature and zinc stress in E...
February 2018: Journal of Thermal Biology
Liam F Fitzsimmons, Lin Liu, Ju-Sim Kim, Jessica Jones-Carson, Andrés Vázquez-Torres
The adaptations that protect pathogenic microorganisms against the cytotoxicity of nitric oxide (NO) engendered in the immune response are incompletely understood. We show here that salmonellae experiencing nitrosative stress suffer dramatic losses of the nucleoside triphosphates ATP, GTP, CTP, and UTP while simultaneously generating a massive burst of the alarmone nucleotide guanosine tetraphosphate. RelA proteins associated with ribosomes overwhelmingly synthesize guanosine tetraphosphate in response to NO as a feedback mechanism to transient branched-chain amino acid auxotrophies...
February 27, 2018: MBio
Ying Zhang, Lin Xia, Liping Lin, Hao Tang, George Osei-Adjei, Shungao Xu, Yiquan Zhang, Xinxiang Huang
Salmonella enterica serovar Typhi (S. Typhi) is the causative agent of human typhoid fever. S. Typhi expresses a major virulence determinant called Vi polysaccharide capsular antigen, which is encoded by the viaB locus containing 10 consecutive genes including tviA and tviB. Expression of Vi antigen is regulated by the two-component regulatory system EnvZ/OmpR and the global RNA-binding factor Hfq. In this study, we show that OmpR coordinates with Hfq to regulate the transcription of Vi antigen genes under osmotic stress conditions...
February 7, 2018: Current Microbiology
Aida Ebrahimi, Laszlo N Csonka, Muhammad A Alam
Heat treatment is one of the most widely used methods for inactivation of bacteria in food products. Heat-induced loss of bacterial viability has been variously attributed to protein denaturation, oxidative stress, or membrane leakage; indeed, it is likely to involve a combination of these processes. We examine the effect of mild heat stress (50-55°C for ≤12 min) on cell permeability by directly measuring the electrical conductance of samples of Salmonella enterica serovar Typhimurium to answer a fundamental biophysical question, namely, how bacteria die under mild heat stress...
February 6, 2018: Biophysical Journal
Shoukui He, Yan Cui, Xiaojie Qin, Fen Zhang, Chunlei Shi, George C Paoli, Xianming Shi
Cross-protection to environmental stresses by ethanol adaptation in Salmonella poses a great threat to food safety because it can undermine food processing interventions. The ability of Salmonella enterica serovar Enteritidis (S. Enteritidis) to develop acid resistance following ethanol adaptation (5% ethanol for 1 h) was evaluated in this study. Ethanol-adapted S. Enteritidis mounted cross-tolerance to malic acid (a two-fold increase in minimum bactericidal concentration), but not to acetic, ascorbic, lactic, citric and hydrochloric acids...
June 2018: Food Microbiology
Dinesh Kumar Patel, Sandeep Mittal, Nimisha Tiwari, Anil Kumar Maurya, Dhirendra Singh, Alok Kumar Pandey, Anirban Pal
Impairment of host immune response in malaria favours bacteraemia caused by typhoidal or non-typhoidal serovars of Salmonella enterica. Ofloxacin and Artesunate are the drugs that are clinically proven for treating typhoid and malaria respectively. The study evaluates the host responses upon treatment with antibiotic (Ofloxacin) and anti-malarial (Artesunate) in a standardized mice model harbouring co-infection. BALB/c mice (18-22 gm) were simultaneously co-infected with Plasmodium yoelii nigeriensis (Pyn) and Salmonella enterica Serovar Typhimurium (STm) and then treated with Ofloxacin or/and Artesunate from day 4 to day 7...
February 1, 2018: Shock
Aoife M Colgan, Heather J Quinn, Stefani C Kary, Lesley A Mitchenall, Anthony Maxwell, Andrew Ds Cameron, Charles J Dorman
DNA in intracellular Salmonella enterica serovar Typhimurium relaxes during growth in the acidified (pH 4 to 5) macrophage vacuole and DNA relaxation correlates with upregulation of Salmonella genes involved in adaptation to the macrophage environment. Bacterial ATP levels did not increase during adaptation to acid pH unless the bacterium was deficient in MgtC, a cytoplasmic-membrane-located inhibitor of proton-driven F1 F0 ATP synthase activity. Inhibiting ATP binding by DNA gyrase and topo IV with novobiocin enhanced the effect of low pH on DNA relaxation...
January 20, 2018: Molecular Microbiology
Tomi Obe, Rama Nannapaneni, Chander Shekhar Sharma, Aaron Kiess
Salmonella enterica serovar Heidelberg (American Type Culture Collection; ATCC 8326) was examined for the ability to adapt to the homologous stress of chlorine through exposure to increasing chlorine concentrations (25 ppm daily increments) in tryptic soy broth (TSB). The tested strain exhibited an acquired tolerance to chlorine in TSB with the tolerant cells growing in concentrations up to 400 ppm. In addition, the chlorine stressed cells displayed rugose morphology on tryptic soy agar (TSA) plates at 37°C...
January 13, 2018: Poultry Science
Soner Yildiz, Béryl Mazel-Sanchez, Matheswaran Kandasamy, Balaji Manicassamy, Mirco Schmolke
BACKGROUND: Microbiota integrity is essential for a growing number of physiological processes. Consequently, disruption of microbiota homeostasis correlates with a variety of pathological states. Importantly, commensal microbiota provide a shield against invading bacterial pathogens, probably by direct competition. The impact of viral infections on host microbiota composition and dynamics is poorly understood. Influenza A viruses (IAV) are common respiratory pathogens causing acute infections...
January 10, 2018: Microbiome
Fang Dong, Lin Xia, Renfei Lu, Xin Zhao, Yiquan Zhang, Ying Zhang, Xinxiang Huang
Bacterial non-coding RNAs (ncRNAs), as important regulatory factors, are involved in many cellular processes, including virulence and protection against environmental stress. The 5' untranslated region (UTR) of malS (named malS-5'UTR), a regulatory ncRNA, increases the invasive capacity and influences histidine biosynthesis in Salmonella enterica serovar Typhi (S. Typhi). In this study, we found that overexpression of the malS-5'UTR decreased S. Typhi survival within macrophages. A microarray analysis of a strain overexpressing the malS-5'UTR revealed a significant increase in the mRNA levels of the atp operon...
January 3, 2018: Microbial Pathogenesis
Nicholas A Stella, Kimberly M Brothers, Jake D Callaghan, Angelina M Passerini, Cihad Sigindere, Preston J Hill, Xinyu Liu, Daniel J Wozniak, Robert M Q Shanks
Secondary metabolites are an important source of pharmaceuticals and key modulators of microbe-microbe interactions. The bacterium Serratia marcescens is part of the Enterobacteriaceae family of eubacteria and produces a number of biologically active secondary metabolites. In this study, we screened for novel regulators of secondary metabolites synthesized by a clinical isolate of S. marcescens and found mutations in a gene for an uncharacterized UmoB/IgaA family member here named gumB Mutation of gumB conferred a severe loss of secondary metabolites prodigiosin and serratamolide...
January 5, 2018: Applied and Environmental Microbiology
Rohit Bansal, Md Anzarul Haque, Prakarsh Yadav, Deepali Gupta, Abdul S Ethayathulla, Md Imtaiyaz Hassan, Punit Kaur
MurE ligase catalyzes the assembly of peptide moiety, an essential component of bacterial cell wall. We have explored the conformational stability and unfolding equilibrium behaviour of the protein MurE ligase by determining the conformational free energy, entropy and enthalpy parameters under stress conditions. MurE from Salmonella enterica Serovar Typhi was cloned, expressed and purified. Conformational changes associated with increasing concentration of GdmCl- and urea-induced denaturation of MurE were monitored using Circular Dichroism (CD) and fluorescence spectroscopies...
December 16, 2017: International Journal of Biological Macromolecules
Marilyn C Erickson, Jye-Yin Liao, Cathy C Webb, Mussie Y Habteselassie, Jennifer L Cannon
Gloves are worn by workers harvesting ready-to-eat produce as a deterrent for contaminating the produce with enteric pathogens that may reside on their hands. As fields are not sterile environments, the probability for gloves to become contaminated still exists and therefore it is critical to understand the conditions that affect the survival of pathogens on gloves. Both Escherichia coli O157:H7 and Salmonella deposited on glove surfaces in a liquid state survived longer when the pathogen had been suspended in lettuce sap than when suspended in water...
February 2, 2018: International Journal of Food Microbiology
Sara M Klee, Islam Mostafa, Sixue Chen, Craig Dufresne, Brian L Lehman, Judith P Sinn, Kari A Peter, Timothy W McNellis
The Gram-negative bacterium Erwinia amylovora causes fire blight, an economically important disease of apples and pears. Elongation factor P (EF-P) is a highly conserved protein that stimulates the formation of the first peptide bond of certain proteins and facilitates the translation of certain proteins, including those with polyproline motifs. YjeK and YjeA are two enzymes involved in the essential post-translational β-lysylation of EF-P at a conserved lysine residue, K34. EF-P, YjeA and YjeK have been shown to be essential for the full virulence of Escherichia coli, Salmonella species and Agrobacterium tumefaciens, with efp, yjeA and yjeK mutants having highly similar phenotypes...
December 12, 2017: Molecular Plant Pathology
Yong Heon Lee, Ji Hye Kim
In Salmonella enterica serovar Typhimurium, the acid-sensing regulator CadC activates transcription of the cadBA operon which contributes to the acid tolerance response. The DNA-binding response regulator OmpR in two-component regulatory system with EnvZ binds to its own promoter for autoinduction. We previously reported that CadC exerts a negative influence on ompR transcription during acid adaptation. However, its underlying mechanisms remain to be elucidated. Here we show that the level of OmpR protein is gradually reduced by a gradual increase in the CadC level using an arabinose-inducible expression system, indicating there exists a negative correlation between the expression levels of two transcription factors...
December 2017: Journal of Microbiology / the Microbiological Society of Korea
Ji-Yeon Hyeon, Shaoting Li, David A Mann, Shaokang Zhang, Zhen Li, Yi Chen, Xiangyu Deng
Metagenomics analysis of food samples promises isolation-independent detection and subtyping of foodborne bacterial pathogens in a single workflow. Selective concentration of Salmonella genomic DNA through immunomagnetic separation (IMS) and multiple displacement amplification (MDA) were shown to shorten culture enrichment of Salmonella -spiked raw chicken breast samples by over 12 hours while permitting serotyping and high-fidelity single nucleotide polymorphisms (SNP) typing of the pathogen using short shotgun sequencing reads...
December 1, 2017: Applied and Environmental Microbiology
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