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https://www.readbyqxmd.com/read/28449226/an-integrated-network-analysis-identifies-how-arcab-enables-metabolic-oscillations-in-the-nitric-oxide-detoxification-network-of-escherichia-coli
#1
Sarah A Sacco, Kristin J Adolfsen, Mark P Brynildsen
The virulences of many pathogens depend on their abilities to detoxify the immune antimicrobial nitric oxide (NO•). The functions of bacterial NO• detoxification machinery depend on oxygen (O2 ), with O2 inhibiting some enzymes, whereas others use it as a substrate. Previously, Escherichia coli NO• detoxification was found to be highly attenuated under microaerobic conditions and metabolic oscillations were observed. The oscillations in [NO•] and [O2 ] were found to result from the inhibitory action of NO• on aerobic respiration, the catalytic inactivation of NO• by Hmp (an NO• dioxygenase), and an imbalanced competition for O2 between Hmp and cytochrome terminal oxidase activity...
April 27, 2017: Biotechnology Journal
https://www.readbyqxmd.com/read/28448750/simultaneous-atrazine-degradation-and-e-coli-inactivation-by-simulated-solar-photo-fenton-like-process-using-persulfate
#2
Natalya Garkusheva, Galina Matafonova, Irina Tsenter, Sara Beck, Valeriy Batoev, Karl Linden
This work evaluated the feasibility of a photo-Fenton-like process using persulfate (PS) and ferrous iron (Fe(2+)) under simulated solar radiation for degrading the herbicide atrazine (ATZ, 6-Chloro-N-ethyl-N'-isopropyl-1,3,5-triazine-2,4-diamine) and inactivating E. coli. Milli Q water, lake water, and diluted wastewater effluents were spiked both simultaneously and separately with ATZ (4 mg/L) and E. coli (10(5) CFU/mL), and exposed to treatment. A method for determining the average irradiance throughout the water media in the UV(A+B) range of the Xe lamp emission was developed for bench-scale experiments...
April 27, 2017: Journal of Environmental Science and Health. Part A, Toxic/hazardous Substances & Environmental Engineering
https://www.readbyqxmd.com/read/28448715/acyl-carrier-protein-cyanylation-delivers-a-ketoacyl-synthase-carrier-protein-crosslink
#3
Grace Thiele, Conne Friedman, Kathleen Tsai, Joris Beld, Casey H Londergan, Louise K Charkoudian
Acyl carrier proteins (ACPs) are central hubs in polyketide and fatty acid biosynthetic pathways, but the fast motions of the ACP's phosphosphopantetheine (Ppant) arm make its conformational dynamics difficult to capture using traditional spectroscopic approaches. Here we report that converting the terminal thiol of E. coli ACP's Ppant arm into a thiocyanate activates this site to form a selective crosslink with the active site cys-teine of its partner ketoacyl synthase (KS; FabF). The reaction releases a cyanide anion, which can be detected by infrared spectroscopy...
April 27, 2017: Biochemistry
https://www.readbyqxmd.com/read/28448574/fusion-expression-of-occludin-extracellular-loops-and-an-%C3%AE-helical-bundle-a-new-research-model-for-tight-junction
#4
Xiaojing Chi, Xia Zhao, Wei Wang, Yuqiang Niu, Min Cheng, Xiuying Liu, Sheng Cui, Wei Yang
Tight junctions (TJs) are the outermost structures of intercellular junctions and are highly specialized membrane domains involved in many important cellular processes. However, most TJ proteins are four-time transmembrane proteins and are difficult to express in their correct soluble form, which limits their functional study and therapeutic application. Human occludin (OCLN) is a major component of TJs and an essential co-receptor for hepatitis C virus (HCV) cell entry. To explore expression strategy for recombinant TJ proteins possessing integrated and functional extracellular loops, OCLN was here used as a model molecule, and several prokaryotic fusion constructs were designed by docking OCLN extracellular loops (ECLs) to HIV-1 gp41 NHR and CHR six-helical bundle (6HV1); then their biophysical features and anti-HCV activity were evaluated...
2017: PloS One
https://www.readbyqxmd.com/read/28448543/heterologous-expression-of-a-thermophilic-diacylglycerol-acyltransferase-triggers-triglyceride-accumulation-in-escherichia-coli
#5
Beatriz Lázaro, Juan A Villa, Omar Santín, Matilde Cabezas, Cintia D F Milagre, Fernando de la Cruz, Gabriel Moncalián
Triglycerides (TAGs), the major storage molecules of metabolic energy and source of fatty acids, are produced as single cell oil by some oleogenic microorganisms. However, these microorganisms require strict culture conditions, show low carbon source flexibilities, lack efficient genetic modification tools and in some cases pose safety concerns. TAGs have essential applications such as behaving as a source for added-value fatty acids or giving rise to the production of biodiesel. Hence, new alternative methods are urgently required for obtaining these oils...
2017: PloS One
https://www.readbyqxmd.com/read/28448512/suppression-of-the-escherichia-coli-dnaa46-mutation-by-changes-in-the-activities-of-the-pyruvate-acetate-node-links-dna-replication-regulation-to-central-carbon-metabolism
#6
Joanna Tymecka-Mulik, Lidia Boss, Monika Maciąg-Dorszyńska, João F Matias Rodrigues, Lidia Gaffke, Anna Wosinski, Grzegorz M Cech, Agnieszka Szalewska-Pałasz, Grzegorz Węgrzyn, Monika Glinkowska
To ensure faithful transmission of genetic material to progeny cells, DNA replication is tightly regulated, mainly at the initiation step. Escherichia coli cells regulate the frequency of initiation according to growth conditions. Results of the classical, as well as the latest studies, suggest that the DNA replication in E. coli starts at a predefined, constant cell volume per chromosome but the mechanisms coordinating DNA replication with cell growth are still not fully understood. Results of recent investigations have revealed a role of metabolic pathway proteins in the control of cell division and a direct link between metabolism and DNA replication has also been suggested both in Bacillus subtilis and E...
2017: PloS One
https://www.readbyqxmd.com/read/28447451/improvement-of-a-p450-based-recombinant-e-coli-whole-cell-system-for-the-production-of-oxygenated-sesquiterpene-derivatives
#7
Thuy Thi Bich Ly, Alexander Schifrin, Bach Duc Nguyen, Rita Bernhardt
Sesquiterpenes are common constituents of essential oil in plants. Their oxygenated derivatives often possess desirable flavor, fragrant and pharmaceutical properties. Recently, the CYP264B1-based recombinant E. coli whole-cell system has been constructed for the oxidation of sesquiterpenes. However, limiting factors of this system related to the high volatility of substrates and the suitability of the P450 redox partner need to be addressed. In this work, the improvement of the system was implemented with (+)-α-longipinene as a model substrate...
April 27, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28447391/transcriptional-response-of-escherichia-coli-to-ammonia-and-glucose-fluctuations
#8
Joana Danica Simen, Michael Löffler, Günter Jäger, Karin Schäferhoff, Andreas Freund, Jakob Matthes, Jan Müller, Ralf Takors
In large-scale production processes, metabolic control is typically achieved by limited supply of essential nutrients such as glucose or ammonia. With increasing bioreactor dimensions, microbial producers such as Escherichia coli are exposed to changing substrate availabilities due to limited mixing. In turn, cells sense and respond to these dynamic conditions leading to frequent activation of their regulatory programmes. Previously, we characterized short- and long-term strategies of cells to adapt to glucose fluctuations...
April 26, 2017: Microbial Biotechnology
https://www.readbyqxmd.com/read/28447026/genome-dynamics-of-escherichia-coli-during-antibiotic-treatment-transfer-loss-and-persistence-of-genetic-elements-in-situ-of-the-infant-gut
#9
Andreas Porse, Heidi Gumpert, Jessica Z Kubicek-Sutherland, Nahid Karami, Ingegerd Adlerberth, Agnes E Wold, Dan I Andersson, Morten O A Sommer
Elucidating the adaptive strategies and plasticity of bacterial genomes in situ is crucial for understanding the epidemiology and evolution of pathogens threatening human health. While much is known about the evolution of Escherichia coli in controlled laboratory environments, less effort has been made to elucidate the genome dynamics of E. coli in its native settings. Here, we follow the genome dynamics of co-existing E. coli lineages in situ of the infant gut during the first year of life. One E. coli lineage causes a urinary tract infection (UTI) and experiences several alterations of its genomic content during subsequent antibiotic treatment...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/28446907/regulation-and-molecular-basis-of-environmental-muropeptide-uptake-and-utilization-in-fastidious-oral-anaerobe-tannerella-forsythia
#10
Angela Ruscitto, Kiyonobu Honma, Vamsee M Veeramachineni, Kiyoshi Nishikawa, Graham P Stafford, Ashu Sharma
Tannerella forsythia is a Gram-negative oral anaerobe associated with periodontitis. This bacterium is auxotrophic for the peptidoglycan amino sugar N-acetylmuramic (MurNAc) and likely relies on scavenging peptidoglycan fragments (muropeptides) released by cohabiting bacteria during their cell wall recycling. Many Gram-negative bacteria utilize an inner membrane permease, AmpG, to transport peptidoglycan fragments into their cytoplasm. In the T. forsythia genome, the Tanf_08365 ORF has been identified as a homolog of AmpG permease...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28446572/evaluation-of-the-accelerate-pheno%C3%A2-system-for-fast-identification-and-antimicrobial-susceptibility-testing-from-positive-blood-culture-in-gram-negative-bloodstream-infection
#11
Matthias Marschal, Johanna Bachmaier, Ingo Autenrieth, Philipp Oberhettinger, Matthias Willmann, Silke Peter
Bloodstream infections (BSI) are an important cause of morbidity and mortality. Increasing rates of antimicrobial resistant pathogens limit treatment options, prompting an empirical use of broad-range antibiotics. Fast and reliable diagnostic tools are needed to provide adequate therapy in a timely manner and to enable a de-escalation of treatment.The Accelerate Pheno™ system (Accelerate Diagnostics, USA) is a fully automated test system that performs both identification (ID) and antimicrobial susceptibility testing (AST) directly from positive blood cultures within approx...
April 26, 2017: Journal of Clinical Microbiology
https://www.readbyqxmd.com/read/28445757/action-of-antimicrobial-peptides-on-bacterial-and-lipid-membranes-a-direct-comparison
#12
Joseph E Faust, Pei-Yin Yang, Huey W Huang
The bacterial membrane represents an attractive target for the design of new antibiotics to combat widespread bacterial resistance. Understanding how antimicrobial peptides (AMPs) and other membrane-active agents attack membranes could facilitate the design of new, effective antimicrobials. Despite intense study of AMPs on model membranes, we do not know how well the mechanism of attack translates to real biological membranes. To that end, we have characterized the attack of AMPs on Escherichia coli cytoplasmic membranes and directly compared this action to model membranes...
April 25, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28445746/crosstalk-and-the-dynamical-modularity-of%C3%A2-feed-forward-loops-in-transcriptional-regulatory-networks
#13
Michael A Rowland, Ahmed Abdelzaher, Preetam Ghosh, Michael L Mayo
Network motifs, such as the feed-forward loop (FFL), introduce a range of complex behaviors to transcriptional regulatory networks, yet such properties are typically determined from their isolated study. We characterize the effects of crosstalk on FFL dynamics by modeling the cross regulation between two different FFLs and evaluate the extent to which these patterns occur in vivo. Analytical modeling suggests that crosstalk should overwhelmingly affect individual protein-expression dynamics. Counter to this expectation we find that entire FFLs are more likely than expected to resist the effects of crosstalk (≈20% for one crosstalk interaction) and remain dynamically modular...
April 25, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28445510/whole-genome-re-sequencing-to-identify-suppressor-mutations-of-mutant-and-foreign-escherichia-coli-ftsz
#14
Kiani A J Arkus Gardner, Masaki Osawa, Harold P Erickson
FtsZ is an essential protein for bacterial cell division, where it forms the cytoskeletal scaffold and may generate the constriction force. We have found previously that some mutant and foreign FtsZ that do not complement an ftsZ null can function for cell division in E. coli upon acquisition of a suppressor mutation somewhere in the genome. We have now identified, via whole genome re-sequencing, single nucleotide polymorphisms in 11 different suppressor strains. Most of the mutations are in genes of various metabolic pathways, which may modulate cell division indirectly...
2017: PloS One
https://www.readbyqxmd.com/read/28445507/various-mutations-compensate-for-a-deleterious-lacz%C3%AE-insert-in-the-replication-enhancer-of-m13-bacteriophage
#15
Emily M Zygiel, Karen A Noren, Marta A Adamkiewicz, Richard J Aprile, Heather K Bowditch, Christine L Carroll, Maria Abigail S Cerezo, Adelle M Dagher, Courtney R Hebert, Lauren E Hebert, Gloria M Mahame, Stephanie C Milne, Kelly M Silvestri, Sara E Sutherland, Alexandria M Sylvia, Caitlyn N Taveira, David J VanValkenburgh, Christopher J Noren, Marilena Fitzsimons Hall
M13 and other members of the Ff class of filamentous bacteriophages have been extensively employed in myriad applications. The Ph.D. series of phage-displayed peptide libraries were constructed from the M13-based vector M13KE. As a direct descendent of M13mp19, M13KE contains the lacZα insert in the intergenic region between genes IV and II, where it interrupts the replication enhancer of the (+) strand origin. Phage carrying this 816-nucleotide insert are viable, but propagate in E. coli at a reduced rate compared to wild-type M13 phage, presumably due to a replication defect caused by the insert...
2017: PloS One
https://www.readbyqxmd.com/read/28445245/ectopic-expression-of-innate-immune-protein-lipocalin-2-in-lactococcus-lactis-protects-against-gut-and-environmental-stressors
#16
Piu Saha, Benoit Chassaing, Beng San Yeoh, Emilie Viennois, Xia Xiao, Mary J Kennett, Vishal Singh, Matam Vijay-Kumar
BACKGROUND: Lipocalin-2 (Lcn2) is a multifunctional innate immune protein that exhibits antimicrobial activity by the sequestration of bacterial siderophores, regulates iron homeostasis, and augments cellular tolerance to oxidative stress. Studies in the murine model of colitis have demonstrated that Lcn2 deficiency exacerbates colitogenesis; however, the therapeutic potential of Lcn2 supplementation has yet to be elucidated. In light of its potential mucoprotective functions, we, herein, investigated whether expression of Lcn2 in the probiotic bacterium can be exploited to alleviate experimental colitis...
April 25, 2017: Inflammatory Bowel Diseases
https://www.readbyqxmd.com/read/28445079/multiple-antimicrobial-resistance-and-novel-point-mutation-in-fluoroquinolone-resistant-escherichia-coli-isolates-from-mangalore-india
#17
Santhosh Kogaluru Shivakumaraswamy, Deekshit Vijaya Kumar, Venugopal Moleyuru Nagarajappa, Iddya Karunasagar, Indrani Karunasagar
Fluoroquinolone resistance in bacteria is usually associated with mutations in the topoisomerase regions. We report a novel point mutation in fluoroquinolone-resistant Escherichia coli strains. E. coli isolated from the environment in and around Mangalore, India, were examined for their antimicrobial resistance profile to 12 antibiotics and for the antibiotic resistance genes by polymerase chain reaction. Of the 67 E. coli isolated, 24 (35.8%) were sensitive to all antibiotics and 43 (64.2%) showed resistance to at least one of the 12 antibiotics used in the study...
April 26, 2017: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
https://www.readbyqxmd.com/read/28444877/identification-and-measurement-of-staphylococcal-enterotoxin-m-sem-from-staphylococcus-aureus-isolate-associated-with-staphylococcal-food-poisoning
#18
Yanying Zhao, Anni Zhu, Junni Tang, Cheng Tang, Juan Chen
Staphylococcus aureus (S. aureus) produces a wide variety of staphylococcal enterotoxins (SEs, SEA to SEX), which are responsible for staphylococcal food poisoning. This study is aimed to establish a system to detect SEM protein in food matrixes. In the present study, sem gene was characterized in a S. aureus isolate H4 associated with food poisoning. The amino acid sequence of the deduced SEM protein was same as that of previously identified SEM from S. aureus 04-02981. Subsequently, mature SEM protein was expressed in E...
April 26, 2017: Letters in Applied Microbiology
https://www.readbyqxmd.com/read/28444752/prevalence-and-pathogen-load-of-campylobacter-spp-salmonella-enterica-and-escherichia-coli-o157-o145-serogroup-in-sheep-faeces-collected-at-sale-yards-and-in-abattoir-effluent-in-western-australia
#19
R Yang, S Abraham, G E Gardner, U Ryan, C Jacobson
OBJECTIVE: Develop a multiplex quantitative PCR assay to investigate the prevalence and shedding of Escherichia coli O157/O145, Salmonella spp. and Campylobacter spp. in sheep at sale yards and abattoirs. METHODS: A qPCR for E. coli O157/O145 was developed, validated and multiplexed with an existing qPCR for Campylobacter and Salmonella enterica. The absolute numbers of E. coli O157/O145, Campylobacter and Salmonella in control samples was determined using droplet digital PCR...
May 2017: Australian Veterinary Journal
https://www.readbyqxmd.com/read/28444379/killing-the-killer-predation-between-protists-and-predatory-bacteria
#20
Julia Johnke, Jens Boenigk, Hauke Harms, Antonis Chatzinotas
Predation by microbes is one of the main drivers of bacterial mortality in the environment. In most ecosystems multiple micro-predators compete at least partially for the same bacterial resource. Predatory interactions between these micro-predators might lead to shifts within microbial communities. Integrating these interactions is therefore crucial for the understanding of ecosystem functioning. In this study we investigated the predation between two groups of micro-predators, i.e. phagotrophic protists and Bdellovibrio and like organisms (BALOs)...
April 21, 2017: FEMS Microbiology Letters
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