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https://www.readbyqxmd.com/read/28431312/melatonin-charge-transfer-complex-with-2-3-dichloro-5-6-dicyano-1-4-benzoquinone-molecular-structure-dft-studies-thermal-analyses-evaluation-of-biological-activity-and-utility-for-determination-of-melatonin-in-pure-and-dosage-forms
#1
Gehad G Mohamed, Maher M Hamed, Nadia G Zaki, Mohamed M Abdou, Marwa El-Badry Mohamed, Abanoub Mosaad Abdallah
A simple, accurate and fast spectrophotometric method for the quantitative determination of melatonin (ML) drug in its pure and pharmaceutical forms was developed based on the formation of its charge transfer complex with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as an electron acceptor. The different conditions for this method were optimized accurately. The Lambert-Beer's law was found to be valid over the concentration range of 4-100μgmL(-1) ML. The solid form of the CT complex was structurally characterized by means of different spectral methods...
April 4, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28431274/distribution-of-escherichia-coli-o157-h7-in-ground-beef-assessing-the-clustering-intensity-for-an-industrial-scale-grinder-and-a-low-and-localized-initial-contamination
#2
Estelle Loukiadis, Clémence Bièche-Terrier, Catherine Malayrat, Franck Ferré, Philippe Cartier, Jean-Christophe Augustin
Undercooked ground beef is regularly implicated in food-borne outbreaks involving pathogenic Shiga toxin-producing Escherichia coli. The dispersion of bacteria during mixing processes is of major concern for quantitative microbiological risk assessment since clustering will influence the number of bacteria the consumers might get exposed to as well as the performance of sampling plans used to detect contaminated ground beef batches. In this study, batches of 25kg of ground beef were manufactured according to a process mimicking an industrial-scale grinding with three successive steps: primary grinding, mixing and final grinding...
March 18, 2017: International Journal of Food Microbiology
https://www.readbyqxmd.com/read/28431245/host-microbe-co-metabolism-dictates-cancer-drug-efficacy-in-c-%C3%A2-elegans
#3
Timothy A Scott, Leonor M Quintaneiro, Povilas Norvaisas, Prudence P Lui, Matthew P Wilson, Kit-Yi Leung, Lucia Herrera-Dominguez, Sonia Sudiwala, Alberto Pessia, Peter T Clayton, Kevin Bryson, Vidya Velagapudi, Philippa B Mills, Athanasios Typas, Nicholas D E Greene, Filipe Cabreiro
Fluoropyrimidines are the first-line treatment for colorectal cancer, but their efficacy is highly variable between patients. We queried whether gut microbes, a known source of inter-individual variability, impacted drug efficacy. Combining two tractable genetic models, the bacterium E. coli and the nematode C. elegans, we performed three-way high-throughput screens that unraveled the complexity underlying host-microbe-drug interactions. We report that microbes can bolster or suppress the effects of fluoropyrimidines through metabolic drug interconversion involving bacterial vitamin B6, B9, and ribonucleotide metabolism...
April 20, 2017: Cell
https://www.readbyqxmd.com/read/28431102/an-escherichia-coli-expression-model-reveals-the-species-specific-function-of-ftsa-from-neisseria-gonorrhoeae-in-cell-division
#4
Yinan Zou, Yan Li, Sanjaya B Ekanayake, Jo-Anne R Dillon
Escherichia coli (Ec) has been used to study the function of cell division proteins from different microorganisms, especially when genetic tools are limited for studying these proteins in their native hosts. The expression of ftsA from N. gonorrhoeae (Ng) disrupted cell division in E. coli resulting in a significant increase in cell length. In some cells, FtsANg localized to the division site and the poles of E. coli cells, but the majority of cells showed no specifical localization. FtsANg did not complement an E...
April 18, 2017: FEMS Microbiology Letters
https://www.readbyqxmd.com/read/28431088/stationary-phase-genes-upregulated-by-polyamines-are-responsible-for-the-formation-of-escherichia-coli-persister-cells-tolerant-to-netilmicin
#5
Alexander G Tkachenko, Natalya M Kashevarova, Elena A Tyuleneva, Mikhail S Shumkov
Persisters are rare phenotypic variants of regular bacterial cells that survive lethal antibiotics or stresses owing to slowing down of their metabolism. Recently, we have shown that polyamine putrescine can upregulate persister cell formation in Escherichia coli via the stimulation of rpoS expression, encoding a master regulator of general stress response. We hypothesized that rmf and yqjD, the stationary-phase genes responsible for ribosome inactivation, might be good candidates for the similar role owing to their involvement in translational arrest and the ability to be affected by polyamines...
April 19, 2017: FEMS Microbiology Letters
https://www.readbyqxmd.com/read/28430938/characterization-of-yjjj-toxin-of-escherichia-coli
#6
Yuki Maeda, Chun-Yi Lin, Yojiro Ishida, Masayori Inouye, Yoshihiro Yamaguchi, Sangita Phadtare
Reminiscent of eukaryotic apoptotic programmed cell death, bacteria also contain a large number of suicide genes, which are in general co-expressed with their cognate antitoxic genes. These systems called the toxin-antitoxin (TA) systems are associated with cellular dormancy, and play major roles in biofilm formation and persistent multi-drug resistance of many human pathogens. In recent years, the study on TA system toxins has become a hot topic due to the health implications of these toxins by virtue of their role in bacterial pathogenicity...
April 19, 2017: FEMS Microbiology Letters
https://www.readbyqxmd.com/read/28430779/a-coevolution-analysis-for-identifying-protein-protein-interactions-by-fourier-transform
#7
Changchuan Yin, Stephen S-T Yau
Protein-protein interactions (PPIs) play key roles in life processes, such as signal transduction, transcription regulations, and immune response, etc. Identification of PPIs enables better understanding of the functional networks within a cell. Common experimental methods for identifying PPIs are time consuming and expensive. However, recent developments in computational approaches for inferring PPIs from protein sequences based on coevolution theory avoid these problems. In the coevolution theory model, interacted proteins may show coevolutionary mutations and have similar phylogenetic trees...
2017: PloS One
https://www.readbyqxmd.com/read/28430446/piecing-together-the-allosteric-patterns-of-chaperonin-groel
#8
Jin Chen, Qian Zhang, Weitong Ren, Wenfei Li
Despite considerable effort, elucidating allostery of large macromolecular assemblies at a molecular level in solution remains technically challenging due to its structural complexity. Here we have employed an approach combining amide backbone hydrogen/deuterium exchange coupled with mass spectrometry, fluorescence spectroscopy and molecular simulations to characterize allosteric patterns of chaperonin GroEL, a ~800 kDa tetradecamer from E. coli. Using available crystal structures of GroEL, we quantitatively map out GroEL allosteric changes in solution by resolving exchange behaviors of 133 overlapping proteolytic peptides with more than 95% sequence coverage...
April 21, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28430425/environmental-growth-of-enterococci-and-escherichia-coli-in-feedlot-catch-basins-and-a-constructed-wetland-in-the-absence-of-fecal-input
#9
Lisa Tymensen, Calvin W Booker, Sherry J Hannon, Shaun R Cook, Rahat Zaheer, Ron Read, Tim A McAllister
Population structures of fecal indicator bacteria (FIB) isolated from catch basins, a constructed wetland, and feces from a beef cattle feedlot were compared over a two-year period. Enterococcus hirae accounted for 92% of the fecal isolates, whereas secondary environments were characterized by greater relative abundance of environmentally adapted species including Enterococcus casseliflavus. While enterococci densities in the catch basins and wetland were similar under wet and drought conditions, E. hirae predominated during rainy periods while E...
April 21, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28430408/amplifying-riboswitch-signal-output-using-cellular-wiring
#10
Michael S Goodson, Annastacia C Bennett, Brenton R Jennewine, Emily Briskin, Svetlana V Harbaugh, Nancy Kelley-Loughnane
If fieldable riboswitch-based biological sensors are to fulfil their potential, it is necessary to increase their signal output. Here we report a novel modular amplification system using a riboswitch to initiate signaling between a sensing strain and a reporter strain of E. coli. A quorum sensing signaling molecule biologically wires the sensing and reporter strains together. The amplification circuit increased the amount of fluorescence generated on ligand binding compared to when the riboswitch controlled fluorescence expression directly...
April 21, 2017: ACS Synthetic Biology
https://www.readbyqxmd.com/read/28430277/rapid-single-cell-detection-and-identification-of-pathogens-by-using-surface-enhanced-raman-spectroscopy
#11
N E Dina, H Zhou, A Colniţă, N Leopold, T Szoke-Nagy, C Coman, C Haisch
For the successful treatment of infections, real-time analysis and enhanced multiplex capacity, sensitivity and cost-effectiveness of the developed detection method are critical. In this work, surface-enhanced Raman scattering (SERS) was employed with the final aim of identification and discrimination of pathogenic bacteria, based on their detected SERS fingerprint at the single-cell level. Several genera of bacteria that are found in most of the isolated infections in bacteraemia were successfully identified in less than 5 minutes without the use of antibodies or other specific receptors...
April 21, 2017: Analyst
https://www.readbyqxmd.com/read/28430101/synthetic-temperature-inducible-lethal-gene-circuits-in-escherichia-coli
#12
Stephanie C Pearce, Ralph L McWhinnie, Francis E Nano
Temperature sensitivity is often used as a way to attenuate micro-organisms to convert them into live vaccines. In this work, we explore the use of temperature-sensitive (TS) genetic circuits that express lethal genes as a widely applicable approach to TS attenuation. We tested different combinations of TS repressors and cognate promoters controlling the expression of genes encoding restriction endonucleases inserted at four different non-essential sites in the Escherichia coli chromosome. We found that the presence of the restriction endonuclease genes did not affect the viability of the host strains at the permissive temperature, but that expression of the genes at elevated temperatures killed the strains to varying extents...
April 22, 2017: Microbiology
https://www.readbyqxmd.com/read/28430025/synthesis-of-dopamine-in-e-coli-using-plasmid-based-expression-system-and-its-marked-effect-on-host-growth-profiles
#13
Arunangshu Das, Anita Verma, Krishna J Mukherjee
L-Dopa and dopamine are important pathway intermediates towards the synthesis of catecholamine like epinephrine and norepinephrine from amino acid L-tyrosine. Dopamine, secreted from dopaminergic nerve cells, serves as an important neurotransmitter. We report the synthesis of dopamine by extending the aromatic amino acid pathway of E.coli DH5α by expression of 4-hydroxyphenylacetate-3-hydrolase (HpaBC) from E.coli and an engineered dopa decarboxylase (DDC) from pig kidney cell. The activity of HpaBC and DDC require 200 µM iron supplementation and 50 µM vitamin B6 respectively as additives to the growth media...
April 21, 2017: Preparative Biochemistry & Biotechnology
https://www.readbyqxmd.com/read/28430004/a-strategy-for-l-isoleucine-dioxygenase-screening-and-4-hydroxyisoleucine-production-by-resting-cells
#14
Chenglin Zhang, Jie Ma, Zhixiang Li, Yunlong Liang, Qingyang Xu, Xixian Xie, Ning Chen
L-Isoleucine dioxygenase (IDO) specifically converts L-isoleucine(L-Ile) to 4-hydroxyisoleucine(4-HIL). To obtain IDO with improved activity, a strategy was developed that is dependent on the restoration of succinate-minus E. coli cell growth by the coupling of L-Ile hydroxylation and the oxidation of α-ketoglutarate(α-KGA) to succinate. Five mutants were obtained with this strategy, and the characteristics of IDO(M3), which exhibited the highest activity, were studied. The catalytic efficiency, thermal stability and catalytic rate of IDO(M3) were significantly improved compared with those of wild-type IDO...
April 21, 2017: Bioengineered
https://www.readbyqxmd.com/read/28429944/biotechnological-production-of-dimethoxyflavonoids-using-a-fusion-flavonoid-o-methyltransferase-possessing-both-3-and-7-o-methyltransferase-activities
#15
Danbi Lee, Hye Lin Park, Sang-Won Lee, Seong Hee Bhoo, Man-Ho Cho
Although they are less abundant in nature, methoxyflavonoids have distinct physicochemical and pharmacological properties compared to common nonmethylated flavonoids. Thus, enzymatic conversion and biotransformation using genetically engineered microorganisms of flavonoids have been attempted for the efficient production of methoxyflavonoids. Because of their regiospecificity, more than two flavonoid O-methyltransferases (FOMTs) and enzyme reactions are required to biosynthesize di(or poly)-methoxyflavonoids...
April 21, 2017: Journal of Natural Products
https://www.readbyqxmd.com/read/28429335/imipenem-resistance-in-serratia-marcescens-is-mediated-by-plasmid-expression-of-kpc-2
#16
W-Q Su, Y-Q Zhu, N-M Deng, L Li
OBJECTIVE: Imipenem is a broad-spectrum carbapenem antibiotic with applications against severe bacterial infections. Here, we describe the identification of imipenem-resistant Serratia marcescens in our hospital and the role of plasmid-mediated KPC-2 expression in imipenem resistance. MATERIALS AND METHODS: We used the modified Hodge test to detect carbapenemase produced in imipenem-resistant strains. RESULTS: His resistance can be transferred to E...
April 2017: European Review for Medical and Pharmacological Sciences
https://www.readbyqxmd.com/read/28429257/low-molecular-weight-components-of-the-metabolome-control-the-proliferative-activity-in-cellular-and-bacterial-cultures
#17
T Ya Vakhitov, N I Chalisova, S I Sitkin, T S Sall, O N Shalaeva, E V Demyanova, A S Morugina, A F Vinogradova, A V Petrov, A D Nozdrachev
The effects of blood metabolites and model cell culture exometabolites found in the human and animal blood metabolomes have been assessed. Specifically, the influence of carboxylic acids that are structural analogues of amino acids and the drug Aktoflor-C have been studied. Methods of organotypic culturing of rat tissues and Escherichia coli bacterial culturing have been used. It has been found that all the tested compounds either stimulate or inhibit cell proliferation in tissue cultures and proliferation in bacterial cultures...
January 2017: Doklady Biological Sciences: Proceedings of the Academy of Sciences of the USSR, Biological Sciences Sections
https://www.readbyqxmd.com/read/28429224/combined-effects-of-m1-muscarinic-acetylcholine-receptor-agonist-tbpb-and-%C3%AE-7n-acetylcholine-receptor-activator-gts-21-on-mouse-mortality-and-blood-concentration-of-proinflammatory-cytokines-in-sepsis
#18
P F Zabrodskii, M S Gromov, V V Maslyakov
Experiments on random-bred albino mice showed that M1 muscarinic acetylcholine receptor agonist (TBPB) and α7n-acetylcholine receptor agonist (GTS-21) significantly reduced mortality of mice with experimental sepsis (intraperitoneally administration of E. coli) in 4 and 24 h after modeling by reducing blood concentration of proinflammatory cytokines TNF-α, IL-1β, and IL-6. Combined treatment with TBPB and GTS-21 determined their additive effect.
April 21, 2017: Bulletin of Experimental Biology and Medicine
https://www.readbyqxmd.com/read/28429192/photoinactivation-effect-of-eosin-methylene-blue-and-chlorophyllin-sodium-copper-against-staphylococcus-aureus-and-escherichia-coli
#19
Cynthia S A Caires, Cassia R B Leal, Carlos A N Ramos, Danielle Bogo, Alessandra R Lima, Eduardo J Arruda, Samuel L Oliveira, Anderson R L Caires, Valter A Nascimento
The use of eosin methylene blue according to Giemsa as photosensitizer is presented for the first time in this paper. The present study evaluated the potential application of chlorophyllin sodium copper salt (CuChlNa) and eosin methylene blue according to Giemsa (EMB) as antimicrobial photosensitizers (aPS) for photodynamic inactivation (PDI) of Staphylococcus aureus (gram-positive) and Escherichia coli (gram-negative) bacteria. The experiments were performed using S. aureus stain ATCC 25923 and E. coli ATCC 25922 in which five aPS concentrations (0...
April 20, 2017: Lasers in Medical Science
https://www.readbyqxmd.com/read/28429156/crystallization-and-preliminary-x-ray-diffraction-analysis-of-a-mammal-inositol-1-3-4-5-6-pentakisphosphate-2-kinase
#20
Elsa Franco-Echevarría, Julia Sanz-Aparicio, Nathalie Troffer-Charlier, Arnaud Poterszman, Beatriz González
Inositol 1,3,4,5,6-pentakisphosphate 2-kinase (IP5 2-K) is an enzyme that catalyses the formation of phytic acid (IP6) from IP5 and ATP. In mammals, IP6 is involved in multiple events such as DNA repair and mRNA edit and it is the precursor of inositol pyrophosphates, emerging compounds shown to have an essential role in apoptosis. In addition, IP5 2-K have functions in cells independently of its catalytic activity, for example in rRNA biogenesis. We pursue the structure determination of a mammal IP5 2-K by Protein Crystallography...
April 21, 2017: Protein Journal
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