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Alison Lacombe, Brendan A Niemira, Joseph Sites, Glenn Boyd, Joshua B Gurtler, Breanna Tyrell, Melissa Fleck
The disinfecting properties of high-intensity monochromatic blue light (MBL) were investigated against Escherichia coli O157:H7, Salmonella , and nonpathogenic bacteria inoculated onto the surface of almonds. MBL was generated from an array of narrow-band 405-nm light-emitting diodes. Almonds were inoculated with higher or lower levels (8 or 5 CFU/g) of pathogenic E. coli O157:H7 and Salmonella , as well as nonpathogenic E. coli K-12 and an avirulent strain of Salmonella Typhimurium, for evaluation as potential surrogates for their respective pathogens...
November 2016: Journal of Food Protection
Naji Al Ibrahim, Jeffrey Green
The Escherichia coli K-12 ydhY-T operon, coding for a predicted oxidoreductase complex, is activated under anaerobic conditions and repressed in the presence of nitrate or nitrite. Anaerobic activation is mediated by the transcription factor FNR and nitrate/nitrite repression is mediated by NarXL and NarQP. In vitro transcription reactions revealed that the DNA upstream of ydhY-T contains sufficient information for RNA polymerase alone to initiate transcription from five locations. FNR severely inhibited synthesis of two of these transcripts (located upstream of, and within, the FNR binding site) and activated the FNR-dependent promoter previously identified in vivo...
February 3, 2017: Microbiology
D Chen, Y Qu, X Hua, L Zhang, Z Liu, S C Pflugfelder, D-Q Li
PurposeTo develop a hyaluronan hydrogel scaffold-based xeno-free culture system for ex vivo cultivation of human corneal epithelial stem cells (CESCs).Patients and MethodsCESCs were cultivated from donor limbal explants on the HyStem-C Hydrogel bio-scaffold in 12-well plates for 3 weeks. Group A used the traditional supplemented hormonal epidermal medium (SHEM) and group B used the defined SHEM (without fetal bovine serum and toxin A, adding 20% serum replacement). The growth and morphology of the cultured cells were assessed by phase contrast microscope...
February 17, 2017: Eye
Rita E Godfrey, David J Lee, Stephen J W Busby, Douglas F Browning
The Escherichia coli K-12 nrf operon encodes a periplasmic nitrite reductase, the expression of which is driven from a single promoter, pnrf. Expression from pnrf is activated by the FNR transcription factor in response to anaerobiosis and further increased in response to nitrite by the response regulator proteins, NarL and NarP. FNR-dependent transcription is suppressed by the binding of two nucleoid associated proteins, IHF and Fis. As Fis levels increase in cells grown in rich medium, the positioning of its binding site, overlapping the promoter -10 element, ensures that pnrf is sharply repressed...
February 17, 2017: Molecular Microbiology
Arthur J Reynolds, Suh-Ruu Ou, Christina F Mondi, Momoko Hayakawa
This article describes the contributions of cognitive-scholastic advantage, family support behavior, and school quality and support as processes through which early childhood interventions promote well-being. Evidence in support of these processes is from longitudinal cohort studies of the Child-Parent Centers and other preventive interventions beginning by age 4. Relatively large effects of participation have been documented for school readiness skills at age 5, parent involvement, K-12 achievement, remedial education, educational attainment, and crime prevention...
February 13, 2017: Child Development
Taesoo Kwon, Won Kim, Seung-Hak Cho
BACKGROUND: The Shiga toxin-producing Escherichia coli (STEC) O157 strain NCCP15739 and non-STEC O157 strain NCCP15738 were isolated from outbreaks in Korea. We characterized NCCP15739 and NCCP15738 by genome sequencing and a comparative genomic analysis using two additional strains, E. coli K-12 substr. MG1655 and O157:H7 EDL933. RESULTS: Using the Illumina HiSeq 2000 platform and the RAST server, the whole genomes of NCCP15739 and NCCP15738 were obtained and annotated...
2017: Gut Pathogens
Bruce R Levin, Ingrid C McCall, Véronique Perrot, Howard Weiss, Armen Ovesepian, Fernando Baquero
: We postulate that the inhibition of growth and low rates of mortality of bacteria exposed to ribosome-binding antibiotics deemed bacteriostatic can be attributed almost uniquely to these drugs reducing the number of ribosomes contributing to protein synthesis, i.e., the number of effective ribosomes. We tested this hypothesis with Escherichia coli K-12 MG1655 and constructs that had been deleted for 1 to 6 of the 7 rRNA (rrn) operons. In the absence of antibiotics, constructs with fewer rrn operons have lower maximum growth rates and longer lag phases than those with more ribosomal operons...
February 7, 2017: MBio
Dehua Xia, Yan Li, Guocheng Huang, Ran Yin, Taicheng An, Guiying Li, Huijun Zhao, Anhuai Lu, Po Keung Wong
This study introduces natural occurring magnetic pyrrhotite (NP) as an environmentally friendly, easy available, and cost-effective alternative catalyst to activate persulfate (PS) of controlling microbial water contaminants. The E. coli K-12 inactivation kinetics observed in batch experiments was well described with first-order reaction. The optimum inactivation rate (k = 0.47 log/min) attained at a NP dose of 1 g/L and a PS dose of 1 mM, corresponding to total inactivation of 7 log10 cfu/mL cells within 15 min...
January 30, 2017: Water Research
Muhammad U Anwar, Jeremy M Rawson, Emma L Gavey, Melanie Pilkington, Ahmed Al-Harrasi, Laurence K Thompson
The synthesis and coordination chemistry of a new open-chain diazine ligand (L4H2) containing bipyridine, oxime and hydrazone functionalities is reported. Reaction of L4H2 with CuCl2·2H2O affords the mononuclear complex [Cu(L4H2)Cl2] (1) in which the ligand acts as a neutral tridentate N,N',N'' donor, whereas treatment with a large excess of CuCl2·2H2O affords the dinuclear complex [Cu2(L4H)Cl3(CH3OH)(H2O)] (2) in which the ligand is singly-deprotonated at the diazine, offering N,N',N'' and N,N' donor sets to two Cu(ii) ions...
February 3, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Patricia A Halpin
Physiology Understanding (PhUn) Week is an annual science outreach program sponsored by the American Physiological Society in which K-12 students learn about physiology through meeting a physiologist and performing an experiment. Performing PhUn Week at an Australian private primary school during a family vacation in 2014 enabled me to receive a fellowship to return the following year for further implementation. To set up the outreach, I contacted the assistant principal of a public primary school, and she connected me with the physical education (PE) teacher...
March 1, 2017: Advances in Physiology Education
Annika Cimdins, Petra Lüthje, Fengyang Li, Irfan Ahmad, Annelie Brauner, Ute Römling
Strains of Escherichia coli exhibit diverse biofilm formation capabilities. E. coli K-12 expresses the red, dry, and rough (rdar) morphotype below 30°C, whereas clinical isolates frequently display the rdar morphotype semiconstitutively. We sequenced the genomes of eight E. coli strains to subsequently investigate the molecular basis of semiconstitutive rdar morphotype expression.
January 26, 2017: Genome Announcements
Alberto Sánchez-Pascuala, Víctor de Lorenzo, Pablo I Nikel
The Embden-Meyerhof-Parnas (EMP) pathway is generally considered to be the biochemical standard for glucose catabolism. Alas, its native genomic organization and the control of gene expression in Escherichia coli are both very intricate, which limits the portability of the EMP pathway to other biotechnologically important bacterial hosts that lack the route. In this work, the genes encoding all the enzymes of the linear EMP route have been individually recruited from the genome of E. coli K-12, edited in silico to remove their endogenous regulatory signals, and synthesized de novo following a standard (GlucoBrick) that enables their grouping in the form of functional modules at the user's will...
February 9, 2017: ACS Synthetic Biology
Cassandra E Nelson, Artur Rogowski, Carl Morland, Joshua A Wilhide, Harry J Gilbert, And Jeffrey G Gardner
Degradation of polysaccharides forms an essential arc in the carbon cycle, provides a percentage of our daily caloric intake, and is a major driver in the renewable chemical industry. Microorganisms proficient at degrading insoluble polysaccharides possess large numbers of carbohydrate active enzymes, many of which have been categorized as functionally redundant. Here we present data that suggests that carbohydrate active enzymes that have overlapping enzymatic activities can have unique, non-overlapping biological functions in the cell...
January 24, 2017: Molecular Microbiology
Garrett T Wong, Richard P Bonocora, Alicia N Schep, Suzannah M Beeler, Anna J Lee Fong, Lauren M Shull, Lakshmi E Batachari, Moira Dillon, Ciaran Evans, Carla J Becker, Eliot C Bush, Johanna Hardin, Joseph T Wade, Daniel M Stoebel
: The alternative sigma factor RpoS is a central regulator of a many stress responses in Escherichia coli The level of functional RpoS differs depending on the stress. The effect of these differing concentrations of RpoS on global transcriptional responses remains unclear. We investigated the effect of RpoS concentration on the transcriptome during stationary phase in rich media. We show that 23% of genes in the E. coli genome are regulated by RpoS level, and we identify many RpoS-transcribed genes and promoters...
January 23, 2017: Journal of Bacteriology
Fernanda Gravina, Tatiane Dobrzanski, Luiz R Olchanheski, Carolina W Galvão, Péricles M Reche, Sonia A Pileggi, Ricardo A Azevedo, Michael J Sadowsky, Marcos Pileggi
Herbicides are continuously used to minimize the loss of crop productivity in agricultural environments. They can, however, cause damage by inhibiting the growth of microbiota via oxidative stress, due to the increased production of reactive oxygen species (ROS). Cellular responses to ROS involve the action of enzymes, including superoxide dismutase (SOD) and catalase (CAT). The objective of this study was to evaluate adaptive responses in Escherichia coli K-12 to paraquat, the active ingredient in the herbicide Gramoxone®...
January 20, 2017: Ecotoxicology and Environmental Safety
Anthony W Kingston, Christine Ponkratz, Elisabeth A Raleigh
: Bacteria use a variety of DNA mobilizing enzymes to facilitate environmental niche adaptation via horizontal gene transfer. This has led to real world problems, like the spread of antibiotic resistance, yet many mobilization proteins remain undefined. Here, we investigate the uncharacterized family of YhgA-like "transposase_31" proteins (PF04754). Our primary focus was the genetic and biochemical properties of the five E. coli K-12 members of this family, which we designate RpnA-RpnE for recombination promoting nuclease...
January 17, 2017: Journal of Bacteriology
Thomas Curran, Fatima Abacha, Stephen Hibberd, Matthew Rolfe, Melissa Lacey, Jeffrey Green
SlyA is a member of the MarR family of bacterial transcriptional regulators. Previously, SlyA has been shown to directly regulate only two operons in Escherichia coli K-12 MG1655, fimB and hlyE (clyA). In both cases SlyA activates gene expression by antagonizing repression by the nucleoid associated protein H-NS. Here the transcript profiles of aerobic glucose-limited steady-state chemostat cultures of E. coli K-12 MG1655, slyA mutant and slyA over-expression strains are reported. The transcript profile of the slyA mutant was not significantly different to that of the parent; however, that of the slyA expression strain was significantly different from that of the vector control...
January 10, 2017: Microbiology
Molly Losh, Gary E Martin, Michelle Lee, Jessica Klusek, John Sideris, Sheila Barron, Thomas Wassink
Genetic liability to autism spectrum disorder (ASD) can be expressed in unaffected relatives through subclinical, genetically meaningful traits, or endophenotypes. This study aimed to identify developmental endophenotypes in parents of individuals with ASD by examining parents' childhood academic development over the school-age period. A cohort of 139 parents of individuals with ASD were studied, along with their children with ASD and 28 controls. Parents' childhood records in the domains of language, reading, and math were studied from grades K-12...
January 9, 2017: Journal of Autism and Developmental Disorders
Juliane Zimmerling, Dirk Tischler, Carolin Großmann, Michael Schlömann, Michel Oelschlägel
Herein, different dehydrogenases (DH) were characterized by applying a novel two-step enzyme assay. We focused on the NAD(P)(+)-dependent phenylacetaldehyde dehydrogenases because they produce industrially relevant phenylacetic acids, but they are not well studied due to limited substrate availability. The first assay step comprises a styrene oxide isomerase (440 U mg(-1)protein) which allows the production of pure phenylacetaldehydes (>70 mmol L(-1)) from commercially available styrene oxides. Thereafter, a DH of interest can be added to convert phenylacetaldehydes in a broad concentration range (0...
January 6, 2017: Applied Biochemistry and Biotechnology
Marvin Kadisch, Andreas Schmid, Bruno Bühler
Fatty acid methyl esters (FAMEs) originating from plant oils are most interesting renewable feedstocks for biofuels and bio-based materials. FAMEs can also be produced and/or functionalized by engineered microbes to give access to, e.g., polymer building blocks. Yet, they are often subject to hydrolysis yielding free fatty acids, which typically are degraded by microbes. We identified BioH as the key enzyme responsible for the hydrolysis of medium-chain length FAME derivatives in different E. coli K-12 strains...
December 24, 2016: Journal of Industrial Microbiology & Biotechnology
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