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stress salmonella

Chayapa Techathuvanan, Doris Helen D'Souza
High intensity ultrasound (HIU) continues to be researched as a nonthermal inactivation technology of appeal to food manufacturers. The advantages of HIU include maintenance of product quality, freshness, product homogenization, along with simultaneous inactivation of pathogens. Besides, it is simple, relatively inexpensive, and easily adaptable to most processing environments. This study investigated the effect of HIU for Salmonella Enteritidis inactivation in culture and liquid whole eggs (LWEs) to decrease egg-associated outbreaks...
May 22, 2018: Journal of Food Science
Julian A Rycroft, Bridget Gollan, Grzegorz J Grabe, Alexander Hall, Angela M Cheverton, Gerald Larrouy-Maumus, Stephen A Hare, Sophie Helaine
Non-typhoidal Salmonella strains are responsible for invasive infections associated with high mortality and recurrence in sub-Saharan Africa, and there is strong evidence for clonal relapse following antibiotic treatment. Persisters are non-growing bacteria that are thought to be responsible for the recalcitrance of many infections to antibiotics. Toxin-antitoxin systems are stress-responsive elements that are important for Salmonella persister formation, specifically during infection. Here, we report the analysis of persister formation of clinical invasive strains of Salmonella Typhimurium and Enteritidis in human primary macrophages...
May 18, 2018: Nature Communications
Felipe Alves de Almeida, Erika Lorena Giraldo Vargas, Deisy Guimarães Carneiro, Uelinton Manoel Pinto, Maria Cristina Dantas Vanetti
Salmonella belongs to the Enterobacteriaceae family which is widely distributed in the environment due to its adaptive capacity to stress conditions. In addition, Salmonella is able to perform a type of cell-to-cell communication called quorum sensing, which leads to differential gene expression. The quorum sensing system mediated by AI-1, acyl homoserine lactones (AHLs), is incomplete in Salmonella because the luxI homolog gene, which encodes for AI-1 synthase, is missing in the genome. However, a homologue of LuxR, known as SdiA, is present and allows the detection of signaling molecules produced by other species of bacteria, leading to regulation of gene expression, mainly related to virulence and biofilm formation...
May 12, 2018: Microbial Pathogenesis
Javier Campos-Gomez, Jorge A Benitez
RNA polymerase containing the stress response regulator σS subunit (RpoS) plays a key role in bacterial survival in hostile environments in nature and during infection. Here we devise and validate a simple cell-based high throughput luminescence assay for this holoenzyme suitable for screening large chemical libraries in a robotic platform.
May 12, 2018: Journal of Microbiological Methods
Nisha Singh, Zeeshan Ahmad, Navin Baid, Ashwani Kumar
Infectious diseases are a major challenge in management of human health worldwide. Recent literature suggests that host immune system could be modulated to ameliorate the pathogenesis of infectious disease. Heme oxygenase (HMOX1) is a key regulator of cellular signaling and it could be modulated using pharmacological reagents. HMOX1 is a cytoprotective enzyme that degrades heme to generate carbon monoxide (CO), biliverdin, and molecular iron. CO and biliverdin (or bilirubin derived from it) can restrict the growth of a few pathogens...
May 14, 2018: IUBMB Life
A S Fernandes, J L Mazzei, H Evangelista, M R C Marques, E R A Ferraz, I Felzenszwalb
Amazon mosses, such as Holomitriopsis laevifolia and Leucobryum sp. are naturally exposed to high levels of solar ultraviolet (UV) radiation. Theoretically, under environmental stress conditions these mosses have developed protective chemical and metabolic strategies against UV damage, by way of biosynthesis of secondary metabolites, such as flavonoids. The present paper aimed to evaluate the free-radical scavenging activity, and the photoprotective, mutagenic and photomutagenic potencies of the methanolic (ME), aqueous (AE), hydroalcoholic (HE), ethanolic (EE) extracts of H...
April 27, 2018: Journal of Photochemistry and Photobiology. B, Biology
Anna Knöppel, Michael Knopp, Lisa M Albrecht, Erik Lundin, Ulrika Lustig, Joakim Näsvall, Dan I Andersson
Experimental evolution under controlled laboratory conditions is becoming increasingly important to address various evolutionary questions, including, for example, the dynamics and mechanisms of genetic adaptation to different growth and stress conditions. In such experiments, mutations typically appear that increase the fitness under the conditions tested (medium adaptation), but that are not necessarily of interest for the specific research question. Here, we have identified mutations that appeared during serial passage of E...
2018: Frontiers in Microbiology
Wei Liu, Yuanyuan Jiang, Jing Sun, Shizhong Geng, Zhiming Pan, Richard A Prinz, Chengming Wang, Jun Sun, Xinan Jiao, Xiulong Xu
Autophagy is a conserved cellular process that functions as a first-line defense to restrict the growth of invading parasitic bacteria. As an intracellular pathogen, Salmonella (S) Typhimurium invades host cells through two Type III secretion systems (T3SS) and resides in the Salmonella-containing vacuole (SCV). When the SCV membrane is perforated and ruptured by T3SS-1, a small portion of the Salmonella egresses from the SCV and replicates rapidly in the nutrient-rich cytosol. Cytosolic Salmonella and those residing in the membrane-damaged SCV are tagged by ubiquitination and marked for autophagy through the ubiquitin-binding adaptor proteins such as p62, NDP52, and optineurin...
May 11, 2018: Cell Death & Disease
Bin Zhang, Bang-Ce Ye
5-Aminolevulinic acid (ALA) is a non-protein amino acid with a significant potential for cancer treatment and plant stress resistance. Microbial fermentation has gradually replaced the traditional chemical-based method for ALA production, thus increasing the need for high-ALA-producing strains. In this study, we engineered the glutamate producing strain, Corynebacterium glutamicum S9114, for ALA production. To efficiently convert l-glutamate to ALA, hemA and hemL from Salmonella typhimurium and Escherichia coli were tandemly overexpressed...
May 2018: 3 Biotech
Xinyu Hong, H Deborah Chen, Eduardo A Groisman
Lipid A is the innermost component of the lipopolysaccharide (LPS) molecules that occupy the outer leaflet of the outer membrane in Gram-negative bacteria. Lipid A is recognized by the host immune system and targeted by cationic antimicrobial compounds. In Salmonella enterica serovar Typhimurium, the phosphates of lipid A are chemically modified by enzymes encoded by targets of the transcriptional regulator PmrA. These modifications increase resistance to the cationic peptide antibiotic polymyxin B by reducing the negative charge of the LPS...
May 8, 2018: Science Signaling
K P Nickerson, S Senger, Y Zhang, R Lima, S Patel, L Ingano, W A Flavahan, D K V Kumar, C M Fraser, C S Faherty, M B Sztein, M Fiorentino, A Fasano
Commensal microorganisms influence a variety of host functions in the gut, including immune response, glucose homeostasis, metabolic pathways and oxidative stress, among others. This study describes how Salmonella Typhi, the pathogen responsible for typhoid fever, uses similar strategies to escape immune defense responses and survive within its human host. To elucidate the early mechanisms of typhoid fever, we performed studies using healthy human intestinal tissue samples and "mini-guts," organoids grown from intestinal tissue taken from biopsy specimens...
April 12, 2018: EBioMedicine
Daniel Ryan, Mohana Mukherjee, Ritu Nayak, Ria Dutta, Mrutyunjay Suar
Salmonella Typhimurium is an enteric pathogen that has evolved masterful strategies to enable survival under stress conditions both within and outside a host. The acid tolerance response (ATR) is one such mechanism that enhances the viability of acid adapted bacteria to lethal pH levels. While numerous studies exist on the protein coding components of this response, there is very little data on the roles of small RNAs (sRNAs). These non-coding RNA molecules have recently been shown to play roles as regulators of bacterial stress response and virulence pathways...
May 3, 2018: Biochimie
Chunlian Tian, Peng Zhang, Caixia Yang, Xiang Gao, Hong Wang, Yuru Guo, Mingchun Liu
The flavonoid fraction was extracted from the leaves of Abutilon theophrasti Medic., which are usually used as a traditional Chinese herbal medicine for the treatment of inflammation and joint pain. The current study focused on the extraction process, component analysis, and in vitro antioxidant, antibacterial, and anti-inflammatory activities of the flavonoid fraction as a part of ongoing research on bioactive substances from natural plant sources. This study evaluated the antioxidant activities via assays of DPPH radical scavenging capacity, ABTS radical scavenging capacity, and reducing power and investigated inhibitory activities against Escherichia coli , Salmonella , Staphylococcus aureus , and Streptococcus ...
2018: Mediators of Inflammation
Imke Spöring, Sebastian Felgner, Matthias Preuße, Denitsa Eckweiler, Manfred Rohde, Susanne Häussler, Siegfried Weiss, Marc Erhardt
Flagellum-driven motility of Salmonella enterica serovar Typhimurium facilitates host colonization. However, the large extracellular flagellum is also a prime target for the immune system. As consequence, expression of flagella is bistable within a population of Salmonella , resulting in flagellated and nonflagellated subpopulations. This allows the bacteria to maximize fitness in hostile environments. The degenerate EAL domain protein RflP (formerly YdiV) is responsible for the bistable expression of flagella by directing the flagellar master regulatory complex FlhD4 C2 with respect to proteolytic degradation...
May 1, 2018: MBio
Oluwatosin Adetola Arojojoye, Ademola Adetokunbo Oyagbemi, Jeremiah Moyinoluwalogo Afolabi
This study evaluated the environmental safety of Igbokoda River, a popular fishing hub in an oil producing area in Nigeria. Biomarkers of oxidative stress and heavy metals were determined in the liver and muscle of Clarias gariepinus from Igbokoda River and also in fish samples from a clean fish farm (control). Water samples from both sites were analysed for physicochemical parameters, heavy metals and bacterial contamination. There was significant increase in the level of heavy metals in water samples and in the organs of fish from Igbokoda River...
April 26, 2018: Bulletin of Environmental Contamination and Toxicology
Markus Tschurtschenthaler, Timon Erik Adolph
Autophagy is a pathway that allows cells to target organelles, protein complexes, or invading microorganisms for lysosomal degradation. The specificity of autophagic processes is becoming increasingly recognized and is conferred by selective autophagy receptors such as Optineurin (OPTN). As an autophagy receptor, OPTN controls the clearance of Salmonella infection and mediates mitochondrial turnover. Recent studies demonstrated that OPTN is critically required for pathogen clearance and an appropriate cytokine response in macrophages...
2018: Frontiers in Immunology
Mayuka Fujimoto, Ryosuke Goto, Takeshi Haneda, Nobuhiko Okada, Tsuyoshi Miki
Salmonella enterica , a common cause of diarrhea, has to colonize the gut lumen to elicit the disease. In the gut, the pathogen encounters a vast array of environmental stresses that cause perturbations in the bacterial envelope. The CpxRA two-component system monitors envelope perturbations and responds by altering the bacteria gene expression profile. This allows Salmonella to survive under such harmful conditions. Therefore, CpxRA activation is likely to contribute to Salmonella gut infection. However, the role of CpxRA-mediated envelope stress response in Salmonella -induced diarrhea is unclear...
April 23, 2018: Infection and Immunity
Callum J Highmore, Jennifer C Warner, Steve D Rothwell, Sandra A Wilks, C William Keevil
The microbiological safety of fresh produce is monitored almost exclusively by culture-based detection methods. However, bacterial food-borne pathogens are known to enter a viable-but-nonculturable (VBNC) state in response to environmental stresses such as chlorine, which is commonly used for fresh produce decontamination. Here, complete VBNC induction of green fluorescent protein-tagged Listeria monocytogenes and Salmonella enterica serovar Thompson was achieved by exposure to 12 and 3 ppm chlorine, respectively...
April 17, 2018: MBio
Fang-Fang Jia, Hui-Qi Zheng, Si-Rui Sun, Xue-Hui Pang, Yu Liang, Jia-Cui Shang, Zong-Tao Zhu, Xiang-Chen Meng
Lactobacillus plantarum , a probiotic, has a high survival rate and high colonization ability in the gastrointestinal tract. Tolerance to the gastrointestinal environment and adhesion to intestinal epithelial cells by some Lactobacillus species (excluding L. plantarum ) are related to luxS /AI-2. Here, the role of luxS in tolerance to simulated digestive juice (SDJ) and adhesion to Caco-2 cells by L. plantarum KLDS1.0391 (hereafter, KLDS1.0391) was investigated. The KLDS1.0391 luxS mutant strain was constructed by homologous recombination...
2018: BioMed Research International
Whee-Soo Kim, Jun-Yeong Lee, Bijay Singh, Sushila Maharjan, Liang Hong, Sang-Mok Lee, Lian-Hua Cui, Ki-June Lee, GiRak Kim, Cheol-Heui Yun, Sang-Kee Kang, Yun-Jaie Choi, Chong-Su Cho
One of the most challenging aspects of probiotics as a replacement for antibiotics is to enhance their antimicrobial activity against pathogens. Given that prebiotics stimulate the growth and/or activity of probiotics, we developed phthalyl inulin nanoparticles (PINs) as prebiotics and observed their effects on the cellular and antimicrobial activities of Pediococcus acidilactici (PA). First, we assessed the internalization of PINs into PA. The internalization of PINs was largely regulated by glucose transporters in PA, and the process was energy-dependent...
April 12, 2018: Scientific Reports
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