Effect of chloramphenicol and starvation for an essential amino acid on polypeptide and polyribonucleotide synthesis in Escherichia coli infected with bacteriophage T4

AbstractThe extracellular serine endopeptidase GluSE (EC 3.4.21.19) is considered to be one of the virulence factors ofStaphylococcus epidermidis. The present study investigated maturation processing of native GluSE and that heterologously expressed inEscherichia coli.In addition to the 28-kDa mature protease, small amounts of proenzymes with molecular masses of 32, 30, and 29 kDa were identified in the extracellular and cell wall-associated fractions. We defined the pre (M1-A27)- and pro (K28-S66)-segments, and found that processing at the E32-S33and D48-I49bonds was responsible for production of the 30- and 29-kDa intermediates, respectively. The full-length form of C-terminally His-tagged GluSE was purified as three proenzymes equivalent to the native ones. These molecules possessing an entire or a part of the pro-segment were proteolytically latent and converted to a mature 28-kDa form by thermolysin cleavage at the S66-V67bond. Mutation of the essential amino acid S235suggested auto-proteolytic production of the 30- and 29-kDa intermediates. Furthermore, an undecapeptide (I56-S66) of the truncated pro-segment not only functions as an inhibitor of the protease but also facilitates thermolysin processing. These findings could offer clues to the molecular mechanism involved in the regulation of proteolytic activity of pathogenic proteases secreted fromS. epidermidis.

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CO-FERMENTION OF MAIZE (Zea mays L.) AND AFRICAN BREAD FRUIT SEED (Treculia africana Dec'ne) FOR THE PRODUCTION OF IMPROVED PAP (OGI)

African Journal of Science and Nature ◽

10.46881/ajsn.v7i0.151 ◽

2020 ◽

Vol 7 ◽

pp. 1

Author(s):

Funmilayo Mujidat Oyeyipo ◽

Olugbenga Samson Taiwo ◽

Yemisi Dorcas Obafemi

Keyword(s):

Escherichia Coli ◽

Amino Acid ◽

Protein Content ◽

Essential Amino Acid ◽

Biochemical Tests ◽

Rotational Viscometer ◽

Fermentation Time ◽

African Breadfruit ◽

Amino Acid Contents

Cereals such as maize are generally having low essential amino acid contents which may cause protein malnutrition. The high essential amino acid in African breadfruit could make it suitable for supplementation of grains/cereals. The microbiological, sensory and nutritional evaluation of cofermented maize (70%) /African breadfruit seed (30%) was carried out. Characterization of isolates were by macroscopic, microscopic and biochemical tests. Standard Methods according to AOAC (1990) were used for proximate compositions and pH determination. Viscosity was measured using Rotational Viscometer. The pH of the co-fermented sample decreased from 6.2±0.01 to 4.2±0.01. Microbial isolates included Coryne bacterium spp., Lactobacillus spp., Escherichia coli, Staphylococcus aureus, Aspergillus niger and Saccharomyces cerevisae in fermenting samples. Escherichia coli was inhibited with increase in fermentation time. Higher microbial counts occurred in maize-African breadfruit ogi (MABO) than maize ogi (MOGI) during primary and secondary -1fermentations. The viscosity of the co-fermented sample was 1.990±0.12 pas . Proximate composition shows that MOGI had lower crude protein content (2.14±0.2) than MABO (9.83±0.3). In contrast, MOGI had higher crude carbohydrate (82.12±0.1 vs 72.59±0.2). Ash, moisture and lipid contents were not significantly different in both samples. Sensory evaluation revealed that MABO recorded higher scores (7±0.02 and 7±0.01) in taste and aroma as against (6±0.01 and 6±0.02) for MOGI. Although consumers accepted both samples, overall, MOGI was more acceptable. MABO oflour kept well and retained their original viscosity after 27 days of storage at (30±2C). MABO gave a dual advantage in that protein content was increased and enteropathogens were inhibited and is therefore recommended for consumption in areas where protein intake is inadequate and food safety is an issue.

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Amino acid similarities to other proteins offer insights into roles of UmuD and UmuC in mutagenesis

Genome ◽

10.1139/g89-110 ◽

1989 ◽

Vol 31 (2) ◽

pp. 594-596 ◽

Cited By ~ 4

Author(s):

John R. Battista ◽

Takehiko Nohmi ◽

Caroline E. Donnelly ◽

Graham C. Walker

Keyword(s):

Escherichia Coli ◽

Amino Acid ◽

Bacteriophage T4 ◽

Sos Response ◽

Genetic Evidence ◽

Chemical Mutagenesis ◽

Accessory Proteins ◽

Terminal Domain ◽

Carboxyl Terminal ◽

Necessary And Sufficient

The products of the umuD and umuC genes are required for most uv and chemical mutagenesis in Escherichia coli. The genes are organized in an operon that is repressed by LexA and regulated as part of the SOS response. The umuD protein shares homology with the carboxyl-terminal domain of LexA. Genetic evidence now indicates that RecA-mediated cleavage activates UmuD for its role in mutagenesis. The COOH-terminal fragment of UmuD is both necessary and sufficient for this role. Similarities of UmuD to gene 45 protein of bacteriophage T4 and of UmuC to gene 44 protein and gene 62 protein suggest possible roles for UmuD and UmuC in mutagenesis that are supported by preliminary evidence.Key words: RecA, UmuD, UmuC, bacteriophage T4, DNA accessory proteins.

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Dietary intake of tryptophan tied emotion-related impulsivity in humans

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831/a000608 ◽

2019 ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Florian Javelle ◽

Descartes Li ◽

Philipp Zimmer ◽

Sheri L. Johnson

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Food Intake ◽

Essential Amino Acid ◽

Food Habits ◽

Psychological Disorder ◽

Serotonin Synthesis ◽

Amino Acid Tryptophan ◽

Pass Through ◽

Three Factor

Abstract. Emotion-related impulsivity, defined as the tendency to say or do things that one later regret during periods of heightened emotion, has been tied to a broad range of psychopathologies. Previous work has suggested that emotion-related impulsivity is tied to an impaired function of the serotonergic system. Central serotonin synthesis relies on the intake of the essential amino acid, tryptophan and its ability to pass through the blood brain barrier. Objective: The aim of this study was to determine the association between emotion-related impulsivity and tryptophan intake. Methods: Undergraduate participants (N = 25, 16 women, 9 men) completed a self-rated measure of impulsivity (Three Factor Impulsivity Index, TFI) and daily logs of their food intake and exercise. These data were coded using the software NutriNote to evaluate intakes of tryptophan, large neutral amino acids, vitamins B6/B12, and exercise. Results: Correlational analyses indicated that higher tryptophan intake was associated with significantly lower scores on two out of three subscales of the TFI, Pervasive Influence of Feelings scores r = –.502, p < . 010, and (lack-of) Follow-Through scores, r = –.407, p < . 050. Conclusion: Findings provide further evidence that emotion-related impulsivity is correlated to serotonergic indices, even when considering only food habits. It also suggests the need for more research on whether tryptophan supplements might be beneficial for impulsive persons suffering from a psychological disorder.

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