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Listeria monocytogenes

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https://www.readbyqxmd.com/read/28816527/use-of-whey-as-a-culture-medium-for-bacillus-clausii-for-the-production-of-protein-hydrolysates-with-antimicrobial-and-antioxidant-activity
#1
Jesús J Rochín-Medina, Hilda K Ramírez-Medina, Jesús G Rangel-Peraza, Karen V Pineda-Hidalgo, Pablo Iribe-Arellano
The use of whey as a natural culture medium to produce hydrolysates with antimicrobial from Bacillus clausii is the objective of this research. The fermentation process was carried out at 25 ℃ for five days, where proteolytic activity, soluble peptides quantification, and antimicrobial activity using the disc diffusion method were determined every day. The fermented whey reached values ​​of proteolytic activity between 90 and 260 U ml(-1) and a production of soluble peptides between 100 and 2070 µg ml(-1)...
January 1, 2017: Food Science and Technology International, Ciencia y Tecnología de Los Alimentos Internacional
https://www.readbyqxmd.com/read/28815044/agonist-anti-gitr-antibody-significantly-enhances-the-therapeutic-efficacy-of-listeria-monocytogenes-based-immunotherapy
#2
Rajeev Shrimali, Shamim Ahmad, Zuzana Berrong, Grigori Okoev, Adelaida Matevosyan, Ghazaleh Shoja E Razavi, Robert Petit, Seema Gupta, Mikayel Mkrtichyan, Samir N Khleif
BACKGROUND: We previously demonstrated that in addition to generating an antigen-specific immune response, Listeria monocytogenes (Lm)-based immunotherapy significantly reduces the ratio of regulatory T cells (Tregs)/CD4(+) and myeloid-derived suppressor cells (MDSCs) in the tumor microenvironment. Since Lm-based immunotherapy is able to inhibit the immune suppressive environment, we hypothesized that combining this treatment with agonist antibody to a co-stimulatory receptor that would further boost the effector arm of immunity will result in significant improvement of anti-tumor efficacy of treatment...
2017: Journal for Immunotherapy of Cancer
https://www.readbyqxmd.com/read/28811611/the-antibacterial-and-antifungal-activity-of-six-essential-oils-and-their-cyto-genotoxicity-to-human-hel-12469-cells
#3
Andrea Puškárová, Mária Bučková, Lucia Kraková, Domenico Pangallo, Katarína Kozics
Six essential oils (from oregano, thyme, clove, lavender, clary sage, and arborvitae) exhibited different antibacterial and antifungal properties. Antimicrobial activity was shown against pathogenic (Escherichia coli, Salmonella typhimurium, Yersinia enterocolitica, Staphylococcus aureus, Listeria monocytogenes, and Enterococcus faecalis) and environmental bacteria (Bacillus cereus, Arthrobacter protophormiae, Pseudomonas fragi) and fungi (Chaetomium globosum, Penicillium chrysogenum, Cladosporium cladosporoides, Alternaria alternata, and Aspergillus fumigatus)...
August 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28809473/aie-materials-with-different-electric-charges-as-artificial-tongue-design-construction-and-assembly-with-various-pathogenic-bacteria-for-effective-bacterial-imaging-and-discrimination
#4
Guang-Jian Liu, Sheng-Nan Tian, Cui-Yun Li, Guo-Wen Xing, Lei Zhou
Imaging-based total bacterial count and type identification of bacteria play crucial rules in clinical diagnostics, public health, biological and medical science, environmental protection. Herein, we designed and synthesized a series of tetraphenylethenes (TPEs) functionalized with one or two aldehyde, carboxylic acid and quaternary ammonium groups, which were successfully used as fluorescent materials for rapid and efficient staining of 8 kinds of representative bacterial species, including pathogenic bacteria Vibrio cholera, Klebsiella pneumoniae, Listeria monocytogenes and potential bioterrorism agent Yersinia pestis...
August 15, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28808162/listeria-monocytogenes-and-shigella-flexneri-activate-the-nlrp1b-inflammasome
#5
Jana Neiman-Zenevich, Sarah Stuart, Mena Abdel-Nour, Stephen E Girardin, Jeremy Mogridge
Activation of the innate immune receptor NLRP1B leads to the formation of an inflammasome, which induces autoproteolytic processing of pro-caspase-1, and ultimately to the release of inflammatory cytokines and to the execution of pyroptosis. One of the signals to which NLRP1B responds is metabolic stress that occurs in cells deprived of glucose or treated with metabolic inhibitors. NLRP1B might, therefore, sense microbial infection as intracellular pathogens such as Listeria monocytogenes and Shigella flexneri cause metabolic stress as a result of nutrient scavenging and host cell damage...
August 14, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28808161/listeria-monocytogenes-has-both-a-bd-type-and-an-aa3-type-terminal-oxidase-which-allow-growth-in-different-oxygen-levels-and-both-are-important-in-infection
#6
David Corbett, Marie Goldrick, Vitor E Fernandes, Kelly Davidge, Robert K Poole, Peter W Andrew, Jennifer Cavet, Ian S Roberts
Listeria monocytogenes is a food borne pathogen responsible for a number of life-threatening infections of humans. During an infection it invades epithelial cells before spreading from the intestine to the cells of the liver and spleen. This requires an ability to adapt to varying oxygen levels. Here we demonstrate that L. monocytogenes has two terminal oxidases, a cytochrome bd-type (CydAB) and a cytochrome aa3 -type menaquinol oxidase (QoxAB) and that both are used for respiration under different oxygen tensions...
August 14, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28808024/structural-and-functional-studies-of-pyruvate-carboxylase-regulation-by-cyclic-di-amp-in-lactic-acid-bacteria
#7
Philip H Choi, Thu Minh Ngoc Vu, Huong Thi Pham, Joshua J Woodward, Mark S Turner, Liang Tong
Cyclic di-3',5'-adenosine monophosphate (c-di-AMP) is a broadly conserved bacterial second messenger that has been implicated in a wide range of cellular processes. Our earlier studies showed that c-di-AMP regulates central metabolism in Listeria monocytogenes by inhibiting its pyruvate carboxylase (LmPC), a biotin-dependent enzyme with biotin carboxylase (BC) and carboxyltransferase (CT) activities. We report here structural, biochemical, and functional studies on the inhibition of Lactococcus lactis PC (LlPC) by c-di-AMP...
August 14, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28807056/agonist-anti-gitr-antibody-significantly-enhances-the-therapeutic-efficacy-of-listeria-monocytogenes-based-immunotherapy
#8
Rajeev Shrimali, Shamim Ahmad, Zuzana Berrong, Grigori Okoev, Adelaida Matevosyan, Ghazaleh Shoja E Razavi, Robert Petit, Seema Gupta, Mikayel Mkrtichyan, Samir N Khleif
BACKGROUND: We previously demonstrated that in addition to generating an antigen-specific immune response, Listeria monocytogenes (Lm)-based immunotherapy significantly reduces the ratio of regulatory T cells (Tregs)/CD4(+) and myeloid-derived suppressor cells (MDSCs) in the tumor microenvironment. Since Lm-based immunotherapy is able to inhibit the immune suppressive environment, we hypothesized that combining this treatment with agonist antibody to a co-stimulatory receptor that would further boost the effector arm of immunity will result in significant improvement of anti-tumor efficacy of treatment...
August 15, 2017: Journal for Immunotherapy of Cancer
https://www.readbyqxmd.com/read/28805458/thermal-inactivation-of-listeria-monocytogenes-and-salmonella-during-water-and-steam-blanching-of-vegetables
#9
Erdogan Ceylan, Wendy McMahon, Donna M Garren
Thermal inactivation of Listeria monocytogenes and Salmonella was evaluated on peas, spinach, broccoli, potatoes, and carrots that were treated with hot water and steam. One gram-positive bacterium, L. monocytogenes, and one gram-negative bacterium, Salmonella, were selected as pertinent human pathogens for evaluation. Samples were inoculated with a composite of five strains each of L. monocytogenes and Salmonella to achieve approximately 10(8) to 10(9) CFU/g. Inoculated samples were treated with hot water at 85 and 87...
September 2017: Journal of Food Protection
https://www.readbyqxmd.com/read/28805457/selection-of-surrogate-bacteria-for-use-in-food-safety-challenge-studies-a-review
#10
Mengyi Hu, Joshua B Gurtler
Nonpathogenic surrogate bacteria are prevalently used in a variety of food challenge studies in place of foodborne pathogens such as Listeria monocytogenes, Salmonella, Escherichia coli O157:H7, and Clostridium botulinum because of safety and sanitary concerns. Surrogate bacteria should have growth characteristics and/or inactivation kinetics similar to those of target pathogens under given conditions in challenge studies. It is of great importance to carefully select and validate potential surrogate bacteria when verifying microbial inactivation processes...
August 14, 2017: Journal of Food Protection
https://www.readbyqxmd.com/read/28805153/investigating-the-susceptibility-of-mice-to-a-bacterial-challenge-after-intravenous-exposure-to-durable-nanoparticles
#11
Saeed Khan, Qin Zhang, Bernard S Marasa, Kidon Sung, Carl E Cerniglia, Taylor Ingle, Margie Yvonne Jones, Angel M Paredes, Grainne A Tobin, Simona Bancos, James L Weaver, Peter L Goering, Paul C Howard, Anil K Patri, Katherine M Tyner
AIM: The goal of this study was to determine whether bacterial clearance in a rodent model would be impaired upon exposure to gold, silver or silica nanoparticles (NPs). MATERIALS & METHODS: Mice received weekly injections of NPs followed by a challenge of Listeria monocytogenes (LM). On days 3 and 10 after LM injections, the animals were sacrificed and their tissues were collected for elemental analysis, electron microscopy and LM count determination. RESULTS: The untreated and NP-treated animals cleared LM at the same rate suggesting that bioaccumulation of NPs did not increase the animals' susceptibility to bacterial infection...
August 14, 2017: Nanomedicine
https://www.readbyqxmd.com/read/28803862/recombinant-lcmv-vectors-induce-protective-immunity-following-homologous-and-heterologous-vaccinations
#12
Jessica Wingerath, Dmitrij Ostroumov, Norman Woller, Michael P Manns, Daniel D Pinschewer, Klaus Orlinger, Ursula Berka, Florian Kühnel, Thomas C Wirth
Successful vaccination against cancer and infectious diseases relies on the induction of adaptive immune responses that induce high-titer antibodies or potent cytoxic T cell responses. In contrast to humoral vaccines, the amplification of cellular immune responses is often hampered by anti-vector immunity that either pre-exists or develops after repeated homologous vaccination. Replication-defective lymphocytic choriomeningitis virus (LCMV) vectors represent a novel generation of vaccination vectors that induce potent immune responses while escaping recognition by neutralizing antibodies...
July 20, 2017: Molecular Therapy: the Journal of the American Society of Gene Therapy
https://www.readbyqxmd.com/read/28803189/efficacy-of-radiant-catalytic-ionization-to-reduce-bacterial-populations-in-air-and-on-different-surfaces
#13
Krzysztof Skowron, Katarzyna Grudlewska, Joanna Kwiecińska-Piróg, Grzegorz Gryń, Mścisław Śrutek, Eugenia Gospodarek-Komkowska
Air contamination by biological agents is often observed in medical or veterinary facilities and industrial plants. Bioaerosols may sediment and pose the surface contamination. Microorganisms present on them may become a source of infections among humans and food contamination. This study determined the use of oxidative gases, including ozone and peroxide, generated by the Radiant Catalytic Ionization (RCI) cell for the inactivation of Acinetobacter baumannii, Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa, Salmonella Enteritidis, Listeria monocytogenes, Staphylococcus aureus, Streptococcus epidermidis, Bacillus subtilis, Clostridium sporogenes, Candida albicans, Aspergillus niger and Penicillium chrysogenumon in air and on different surfaces...
August 10, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28803156/sequential-transition-of-the-injury-phenotype-temperature-dependent-survival-and-transcriptional-response-in-listeria-monocytogenes-following-lethal-h2o2-exposure
#14
Yoshitsugu Ochiai, Fumiya Yamada, Yuko Yoshikawa, Mariko Mochizuki, Takashi Takano, Ryo Hondo, Fukiko Ueda
The food-borne pathogen Listeria monocytogenes is present persistently in food processing environments, where this bacterium is exposed to various stress factors, including oxidative stress. This study aimed to elucidate the temperature-dependent response of L. monocytogenes to H2O2 exposure and the phenotypic changes in colony formation by H2O2-treated bacteria. Survival curves indicated an increase in the resistance to H2O2 in L. monocytogenes as the temperature decreased during the stress exposure procedure...
August 3, 2017: International Journal of Food Microbiology
https://www.readbyqxmd.com/read/28803013/short-communication-detection-of-stx2-and-elt-genes-in-bovine-milk-by-using-a-multiplex-pcr-system
#15
R D S Nandi, A C Campos, J J Puño-Sarmiento, R P Maluta, S P D Rocha, R K T Kobayashi, G Nakazato
The aim of this study was to detect 2 important toxin genes from diarrheagenic Escherichia coli (DEC) in bovine milk using a new multiplex PCR. To standardize the multiplex PCR, the stx2 and elt genes were investigated for the detection of Shiga toxin-producing Escherichia coli (STEC) and enterotoxigenic E. coli (ETEC), respectively. The DNA template was prepared with a thermal procedure (boiling) and a commercial kit. Samples consisted of UHT and pasteurized milk, both skimmed, and STEC and ETEC were tested in concentrations between 10(1) and 10(9) cfu/mL...
August 9, 2017: Journal of Dairy Science
https://www.readbyqxmd.com/read/28803008/two-step-large-volume-magnetic-separation-combined-with-pcr-assay-for-sensitive-detection-of-listeria-monocytogenes-in-pasteurized-milk
#16
Dan Luo, Xiaolin Huang, Yan Mao, Chaochao Chen, Fulai Li, Hengyi Xu, Yonghua Xiong
Immunomagnetic separation (IMS) is an effective tool for the preconcentration and purification of food-borne pathogens from complex food samples because of its high capture efficiency (CE). In conventional IMS, antibodies are usually conjugated on the surface of magnetic beads (MB); the random orientation and conformation changes of antibodies on the MB surface can decrease their bioactivity. Moreover, the Brownian motion of immobilized antibodies is weakened, thereby rendering their binding efficiency with bacteria lower than that of free antibodies...
August 9, 2017: Journal of Dairy Science
https://www.readbyqxmd.com/read/28802046/replication-transcription-conflicts-generate-r-loops-that-orchestrate-bacterial-stress-survival-and-pathogenesis
#17
Kevin S Lang, Ashley N Hall, Christopher N Merrikh, Mark Ragheb, Hannah Tabakh, Alex J Pollock, Joshua J Woodward, Julia E Dreifus, Houra Merrikh
Replication-transcription collisions shape genomes, influence evolution, and promote genetic diseases. Although unclear why, head-on transcription (lagging strand genes) is especially disruptive to replication and promotes genomic instability. Here, we find that head-on collisions promote R-loop formation in Bacillus subtilis. We show that pervasive R-loop formation at head-on collision regions completely blocks replication, elevates mutagenesis, and inhibits gene expression. Accordingly, the activity of the R-loop processing enzyme RNase HIII at collision regions is crucial for stress survival in B...
August 10, 2017: Cell
https://www.readbyqxmd.com/read/28800831/characterization-of-enterococcus-durans-152-bacteriocins-and-their-inhibition-of-listeria-monocytogenes-in-ham
#18
Lihui Du, Fang Liu, Ping Zhao, Tong Zhao, Michael P Doyle
Listeria monocytogenes is a nonfastidious, widely occurring foodborne pathogen that is a major challenge to the food industry. Enterococcus durans 152, a confirmed L. monocytogenes-control microorganism, was isolated from floor drain samples from a food processing facility. In this study, the two bacteriocins produced by E. durans 152 were characterized and identified as Dur 152A (an enterocin L50A derivative with two amino acid substitutions of I→M) and enterocin L50B. The bacteriocins were then partially purified and evaluated for inhibitory activity to L...
December 2017: Food Microbiology
https://www.readbyqxmd.com/read/28800830/modeling-carbon-dioxide-effect-in-a-controlled-atmosphere-and-its-interactions-with-temperature-and-ph-on-the-growth-of-l-%C3%A2-monocytogenes-and-p-%C3%A2-fluorescens
#19
Olivier Couvert, Stéphanie Guégan, Bernard Hézard, Véronique Huchet, Adrienne Lintz, Dominique Thuault, Valérie Stahl
The effect of carbon dioxide, temperature, and pH on growth of Listeria monocytogenes and Pseudomonas fluorescens was studied, following a protocol to monitor microbial growth under a constant gas composition. In this way, the CO2 dissolution didn't modify the partial pressures in the gas phase. Growth curves were acquired at different temperatures (8, 12, 22 and 37 °C), pH (5.5 and 7) and CO2 concentration in the gas phase (0, 20, 40, 60, 80, 100% of the atmospheric pressure, and over 1 bar). These three factors greatly influenced the growth rate of L...
December 2017: Food Microbiology
https://www.readbyqxmd.com/read/28800829/combination-of-endolysins-and-high-pressure-to-inactivate-listeria-monocytogenes
#20
Tomas J van Nassau, Christian A Lenz, Anna S Scherzinger, Rudi F Vogel
Outbreaks of listeriosis are often related to the consumption of low-processed ready-to-eat food products (e.g. soft cheeses or smoked fish) contaminated with Listeria monocytogenes. Traditional preservation techniques, such as heat treatment, cannot eliminate Listeria from these products without strongly affecting the quality of the foods. We therefore investigated the use of endolysin (PlyP40, Ply511, or PlyP825) in combination with high hydrostatic pressure processing to kill L. monocytogenes in buffer...
December 2017: Food Microbiology
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