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bacterial genetics

G Kamkamidze, I Migriauli, D Razmadze, M Kochlamazashvili, K Mulkijanyan, M Butsashvili
The main objective of this investigation was to develop and pilot a real-time Polymerase Chain Reaction (rt-PCR) diagnostic system for rapid and simultaneous identification of pathogens with a particular emphasis on diarrheal disease diagnostics. The diarrheal diseases were selected as a target for the pilot because they constitute a primary public health priority in Georgia and worldwide. The product developed by our research team "Neo_PCR_Diagnostics" represents an original system for the identification of pathogens associated with gastrointestinal tract infections and diarrhea...
September 2016: Georgian Medical News
Yanfeng Zhang, Yong Xu, Wei Fang, Xiaotang Wang, Zemin Fang, Yazhong Xiao
A taxonomic study was carried out on a Gram-stain negative, rod-shaped, non-flagellated, and facultatively anaerobic bacterial strain designated as strain SF-16(T), which was isolated from an unidentified starfish in Sanya, China. Strain SF-16(T) was found to be 5.0-7.0 μm long, and oxidase and catalase positive. Cell growth was observed at pH 6.0-8.5 (optimum, 7.0-8.0), temperatures of 10-41 °C (optimum, 25-30 °C), and salinities of 0-12 % (optimum, 3.0-6.0 %). The predominant fatty acids (>20 %) were found to be C18:1 ω7c and/or C18:1 ω6c (summed feature 8)...
October 21, 2016: Antonie Van Leeuwenhoek
Daniel Nichol, Mark Robertson-Tessi, Peter Jeavons, Alexander R A Anderson
Non-genetic variation in phenotypes, or bet-hedging, has been observed as a driver of drug resistance in both bacterial infections and cancers. Here, we study how bet-hedging emerges in the genotype-phenotype mapping through a simple interaction model: a molecular switch. We use simple Chemical Reaction Networks to implement stochastic switches that map gene products to phenotypes and investigate the impact of structurally distinct mappings on the evolution of phenotypic heterogeneity. Bet-hedging naturally emerges within this model and is robust to evolutionary loss through mutations to both the expression of individual genes and to the network itself...
October 21, 2016: Genetics
Pierre Dehoux, Jean Christophe Marvaud, Amr Abouelleil, Ashlee M Earl, Thierry Lambert, Catherine Dauga
BACKGROUND: Clostridium bolteae and Clostridium clostridioforme, previously included in the complex C. clostridioforme in the group Clostridium XIVa, remain difficult to distinguish by phenotypic methods. These bacteria, prevailing in the human intestinal microbiota, are opportunistic pathogens with various drug susceptibility patterns. In order to better characterize the two species and to obtain information on their antibiotic resistance genes, we analyzed the genomes of six strains of C...
October 21, 2016: BMC Genomics
Yohann Nédélec, Joaquín Sanz, Golshid Baharian, Zachary A Szpiech, Alain Pacis, Anne Dumaine, Jean-Christophe Grenier, Andrew Freiman, Aaron J Sams, Steven Hebert, Ariane Pagé Sabourin, Francesca Luca, Ran Blekhman, Ryan D Hernandez, Roger Pique-Regi, Jenny Tung, Vania Yotova, Luis B Barreiro
Individuals from different populations vary considerably in their susceptibility to immune-related diseases. To understand how genetic variation and natural selection contribute to these differences, we tested for the effects of African versus European ancestry on the transcriptional response of primary macrophages to live bacterial pathogens. A total of 9.3% of macrophage-expressed genes show ancestry-associated differences in the gene regulatory response to infection, and African ancestry specifically predicts a stronger inflammatory response and reduced intracellular bacterial growth...
October 20, 2016: Cell
Hélène Quach, Maxime Rotival, Julien Pothlichet, Yong-Hwee Eddie Loh, Michael Dannemann, Nora Zidane, Guillaume Laval, Etienne Patin, Christine Harmant, Marie Lopez, Matthieu Deschamps, Nadia Naffakh, Darragh Duffy, Anja Coen, Geert Leroux-Roels, Frederic Clément, Anne Boland, Jean-François Deleuze, Janet Kelso, Matthew L Albert, Lluis Quintana-Murci
Humans differ in the outcome that follows exposure to life-threatening pathogens, yet the extent of population differences in immune responses and their genetic and evolutionary determinants remain undefined. Here, we characterized, using RNA sequencing, the transcriptional response of primary monocytes from Africans and Europeans to bacterial and viral stimuli-ligands activating Toll-like receptor pathways (TLR1/2, TLR4, and TLR7/8) and influenza virus-and mapped expression quantitative trait loci (eQTLs)...
October 20, 2016: Cell
Steven Z Josefowicz, Miho Shimada, Anja Armache, Charles H Li, Rand M Miller, Shu Lin, Aerin Yang, Brian D Dill, Henrik Molina, Hee-Sung Park, Benjamin A Garcia, Jack Taunton, Robert G Roeder, C David Allis
The inflammatory response requires coordinated activation of both transcription factors and chromatin to induce transcription for defense against pathogens and environmental insults. We sought to elucidate the connections between inflammatory signaling pathways and chromatin through genomic footprinting of kinase activity and unbiased identification of prominent histone phosphorylation events. We identified H3 serine 28 phosphorylation (H3S28ph) as the principal stimulation-dependent histone modification and observed its enrichment at induced genes in mouse macrophages stimulated with bacterial lipopolysaccharide...
October 20, 2016: Molecular Cell
Michael R Gillings, Ian T Paulsen, Sasha G Tetu
Antibiotic resistance arises as a consequence of complex interactions among genes, mobile elements, and their bacterial hosts, coupled with the intense selection pressures imposed by humans in an attempt to control bacterial growth. Understanding the evolution of resistance requires an understanding of interacting cellular and genetic components. Here, we review how DNA analysis has helped reconstruct the origins of the mosaic, multiresistant mobile elements that have spread through pathogens in the last 60 years...
October 21, 2016: Annals of the New York Academy of Sciences
Jennifer H Madenspacher, Michael B Fessler
Although community-acquired pneumonia remains a major public health problem, murine models of bacterial pneumonia have recently facilitated significant preclinical advances in our understanding of the underlying cellular and molecular pathogenesis. In vivo mouse models capture the integrated physiology and resilience of the host defense response in a manner not revealed by alternative, simplified ex vivo approaches. Several methods have been described in the literature for intrapulmonary inoculation of bacteria in mice, including aerosolization, intranasal delivery, peroral endotracheal cannulation under 'blind' and visualized conditions, and transcutaneous endotracheal cannulation...
September 28, 2016: Journal of Visualized Experiments: JoVE
Shivanand Hegde, Martina Zimmermann, Martina Flöck, Rene Brunthaler, Joachim Spergser, Renate Rosengarten, Rohini Chopra-Dewasthaly
Mycoplasmas are amongst the most successful pathogens of both humans and animals yet the molecular basis of mycoplasma pathogenesis is poorly understood. This is partly due to the lack of classical virulence factors and little similarity to common bacterial pathogenic determinants. Using Mycoplasma agalactiae as a model we initiated research in this direction by screening a transposon mutant library in the natural sheep host using a negative selection method. Having successfully identified putative factors involved in the colonization of local infection and lymphogenic sites, the current study assessed mutants unable to spread systemically in sheep after experimental intramammary infection...
October 20, 2016: Veterinary Research
Sebastien Breurec, Coralie Bouchiat, Jean-Marie Sire, Olivier Moquet, Raymond Bercion, Moussa Fafa Cisse, Philippe Glaser, Ousmane Ndiaye, Sidy Ka, Helene Salord, Abdoulaye Seck, Haby Signate Sy, Remy Michel, Benoit Garin
BACKGROUND: Neonatal infection constitutes one of Senegal's most important public health problems, with a mortality rate of 41 deaths per 1,000 live births. METHODS: Between January 2007 and March 2008, 242 neonates with suspected infection were recruited at three neonatal intensive care units in three major tertiary care centers in Dakar, the capital of Senegal. Neonatal infections were confirmed by positive bacterial blood or cerebrospinal fluid culture. The microbiological pattern of neonatal infections and the antibiotic susceptibility of the isolates were characterized...
October 20, 2016: BMC Infectious Diseases
Abhishek Srivastava, Katherine D McMahon, Ramunas Stepanauskas, Hans-Peter Grossart
The National Center for Biotechnology Information [] database enlists more than 15,500 bacterial species. But this also includes a plethora of uncultured bacterial representations. Owing to their metabolism, they directly influence biogeochemical cycles, which underscores the the important status of bacteria on our planet. To study the function of a gene from an uncultured bacterium, we have undertaken a de novo gene synthesis approach. Actinobacteria of the acI-B subcluster are important but yet uncultured members of the bacterioplankton in temperate lakes of the northern hemisphere such as oligotrophic Lake Stechlin (NE Germany)...
December 2015: International Microbiology: the Official Journal of the Spanish Society for Microbiology
Chijun Li, Brandon K Tan, Jinshi Zhao, Ziqiang Guan
Phosphatidylglycerol (PG) makes up 5-20% of the phospholipids of Escherichia coli and is essential for growth in wild-type cells. PG is synthesized from the dephosphorylation of its immediate precursor, phosphatidylglycerol phosphate (PGP) whose synthase in E. coli is PgsA. Using genetic, biochemical and highly sensitive mass spectrometric approaches, we identified an alternative mechanism for PG synthesis in E. coli that is PgsA independent. The reaction of synthesis involves the conversion of phosphatidylethanolamine and glycerol into PG and is catalyzed by ClsB, a phospholipase D-type cardiolipin synthase...
October 19, 2016: Journal of Biological Chemistry
Awa Diop, Saber Khelaifia, Nicholas Armstrong, Noémie Labas, Pierre-Edouard Fournier, Didier Raoult, Matthieu Million
BACKGROUND: Microbial culturomics represents an ongoing revolution in the characterization of environmental and human microbiome. METHODS: By using three media containing high salt concentration (100, 150, and 200 g/L), the halophilic microbial culturome of a commercial table salt was determined. RESULTS: Eighteen species belonging to the Terrabacteria group were isolated including eight moderate halophilic and 10 halotolerant bacteria. Gracilibacillus massiliensis sp...
2016: Microbial Ecology in Health and Disease
Marissa B Guzzo, Hoa T Nguyen, Thanh H Pham, Monika Wyszczelska-Rokiel, Hieronim Jakubowski, Kerstin A Wolff, Sam Ogwang, Joseph L Timpona, Soumya Gogula, Michael R Jacobs, Markus Ruetz, Bernhard Kräutler, Donald W Jacobsen, Guo-Fang Zhang, Liem Nguyen
The methylfolate trap, a metabolic blockage associated with anemia, neural tube defects, Alzheimer's dementia, cardiovascular diseases, and cancer, was discovered in the 1960s, linking the metabolism of folate, vitamin B12, methionine and homocysteine. However, the existence or physiological significance of this phenomenon has been unknown in bacteria, which synthesize folate de novo. Here we identify the methylfolate trap as a novel determinant of the bacterial intrinsic death by sulfonamides, antibiotics that block de novo folate synthesis...
October 2016: PLoS Pathogens
Deepti Varshney, Akanksha Jaiswar, Alok Adholeya, Pushplata Prasad
BACKGROUND: Subtilisin-like serine proteases or Subtilases in fungi are important for penetration and colonization of host. In Hypocreales, these proteins share several properties with other fungal, bacterial, plant and mammalian homologs. However, adoption of specific roles in entomopathogenesis may be governed by attainment of unique biochemical and structural features during the evolutionary course. Due to such functional shifts Subtilases coded by different family members of Hypocreales acquire distinct features according to respective hosts and lifestyle...
October 19, 2016: BMC Evolutionary Biology
Dar-Chone Chow, Kacie Rice, Wanzhi Huang, Robert L Atmar, Timothy G Palzkill
The β-lactamase inhibitory protein (BLIP) binds and inhibits a wide range of class A β-lactamases including the TEM-1 β-lactamase (Ki= 0.5 nM), which is widely present in Gram-negative bacteria, and the KPC-2 β-lactamase (Ki= 1.2 nM), which hydrolyzes virtually all clinically useful β-lactam antibiotics. The extent to which the specificity of a protein that binds a broad range of targets can be modified to display narrow specificity was explored in this study by engineering BLIP to bind selectively to KPC-2 β-lactamase...
October 18, 2016: ACS Infectious Diseases
Evgeny Vinogradov, Irina Sadovskaya, Thierry Grard, Marie-Pierre Chapot-Chartier
Lactobacillus casei is a Gram positive lactic acid bacterium used in dairy fermentations and present in the normal human gut microbiota. Certain strains are recognized as probiotics with beneficial effects on human and animal health. L. casei BL23 is a potential probiotic strain endowed with anti-inflammatory properties and a model strain widely used in genetic, physiological and biochemical studies. A number of bacterial cell surface polysaccharides have been shown to play a role in the immune modulation activities observed for probiotic lactic acid bacteria...
October 8, 2016: Carbohydrate Research
Martinus J A Daas, Antonius H P van de Weijer, Willem M de Vos, John van der Oost, Richard van Kranenburg
BACKGROUND: Due to the finite nature of global oil resources we are now faced with the challenge of finding renewable resources to produce fuels and chemicals in the future. Lactic acid has great potential as a precursor for the production of bioplastics alternatives to conventional plastics. Efficient lactic acid fermentation from non-food lignocellulosic substrates requires pretreatment and saccharification to generate fermentable sugars. A fermentation process that requires little to no enzyme additions, i...
2016: Biotechnology for Biofuels
Martha S Hunter, Peter Asiimwe, Anna G Himler, Suzanne E Kelly
Arthropods commonly carry maternally-inherited intracellular bacterial symbionts that may profoundly influence host biology and evolution. The intracellular symbiont Rickettsia sp. nr. bellii swept rapidly into populations of the sweetpotato whitefly Bemisia tabaci in the southwestern USA. Previous laboratory experiments showed female-bias and fitness benefits were associated with Rickettsia infection, potentially explaining the high frequencies of infection observed in field populations, but the effects varied with whitefly genetic line...
October 17, 2016: Journal of Evolutionary Biology
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