Chloral hydrate inhibits protein synthesis in vivo

ABSTRACT Two variations of the method of localized mutagenesis were used to introduce mutations into the 72 min region of the Escherichia coli chromosome. Twenty temperature-sensitive mutants, with linkage to markers in this region, have been examined. Each strain showed an inhibition of growth in liquid medium at 44°, and 19 of the mutants lost viability upon prolonged incubation at this temperature. A reduction in the rate of in vivo RNA and protein synthesis was observed for each mutant at 44°, relative to a control strain. Eleven of the mutants were altered in growth sensitivity or resistance to one or more of three ribosomal antibiotics. The incomplete assembly of ribosomal subunits was detected in nine strains grown at 44°. The characteristics of these mutants suggest that many of them are altered in genes for translational or transcriptional components, consistent with the clustering of these genes at this chromosomal locus.

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Suppression of Amber Codons in Vivo as Evidence That Mutants Derived from Escherichia coli Initiator tRNA Can Act at the Step of Elongation in Protein Synthesis

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)83376-2 ◽

1989 ◽

Vol 264 (11) ◽

pp. 6504-6508

Author(s):

B L Seong ◽

C P Lee ◽

U L RajBhandary

Keyword(s):

Escherichia Coli ◽

Protein Synthesis ◽

Initiator Trna

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Comprehensive assessment of post-prandial protein handling by the application of intrinsically labelled protein in vivo in human subjects

Proceedings of The Nutrition Society ◽

10.1017/s0029665120008034 ◽

2021 ◽

pp. 1-9

Author(s):

Jorn Trommelen ◽

Andrew M. Holwerda ◽

Philippe J. M. Pinckaers ◽

Luc J. C. van Loon

Keyword(s):

Protein Synthesis ◽

Amino Acid ◽

Stable Isotope ◽

Dietary Protein ◽

Protein Metabolism ◽

Muscle Protein ◽

Human Subjects ◽

Whole Body ◽

Body Protein

All human tissues are in a constant state of remodelling, regulated by the balance between tissue protein synthesis and breakdown rates. It has been well-established that protein ingestion stimulates skeletal muscle and whole-body protein synthesis. Stable isotope-labelled amino acid methodologies are commonly applied to assess the various aspects of protein metabolism in vivo in human subjects. However, to achieve a more comprehensive assessment of post-prandial protein handling in vivo in human subjects, intravenous stable isotope-labelled amino acid infusions can be combined with the ingestion of intrinsically labelled protein and the collection of blood and muscle tissue samples. The combined application of ingesting intrinsically labelled protein with continuous intravenous stable isotope-labelled amino acid infusion allows the simultaneous assessment of protein digestion and amino acid absorption kinetics (e.g. release of dietary protein-derived amino acids into the circulation), whole-body protein metabolism (whole-body protein synthesis, breakdown and oxidation rates and net protein balance) and skeletal muscle metabolism (muscle protein fractional synthesis rates and dietary protein-derived amino acid incorporation into muscle protein). The purpose of this review is to provide an overview of the various aspects of post-prandial protein handling and metabolism with a focus on insights obtained from studies that have applied intrinsically labelled protein under a variety of conditions in different populations.

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Effect of microbial isolates on microbial yield estimation in RUSITEC system

BSAP Occasional Publication ◽

10.1017/s0263967x0003295x ◽

1998 ◽

Vol 22 ◽

pp. 306-308

Author(s):

M. D. Carro ◽

E. L. Miller

Keyword(s):

Protein Synthesis ◽

Liquid Phase ◽

Solid Phase ◽

Liquid Fraction ◽

Microbial Protein ◽

Microbial Protein Synthesis ◽

Continuous Culture System ◽

The One

The estimation of rumen microbial protein synthesis is one of the main points in the nitrogen (N)-rationing systems for ruminants, as microbial protein provides proportionately 0.4 to 0.9 of amino acids entering the small intestine in ruminants receiving conventional diets (Russell et al., 1992). Methods of estimating microbial protein synthesis rely on marker techniques in which a particular microbial constituent is related to the microbial N content. Marker : N values have generally been established in mixed bacteria isolated from the liquid fraction of rumen digesta and it has been assumed that the same relationship holds in the total population leaving the rumen (Merry and McAllan, 1983). However, several studies have demonstrated differences in composition between solid-associated (SAB) and fluid-associated bacteria in vivo (Legay-Carmier and Bauchart, 1989) and in vitro (Molina Alcaide et al, 1996), as well in marker : N values (Pérez et al., 1996). This problem could be more pronounced in the in vitro semi-continuous culture system RUSITEC, in which there are three well defined components (a free liquid phase, a liquid phase associated with the solid phase and a solid phase), each one having associated microbial populations.The objective of this experiment was to investigate the effect of using different bacterial isolates (BI) on the estimation of microbial production of four different diets in RUSITEC (Czerkawski and Breckenridge, 1977), using (15NH4)2 SO4 as microbial marker, and to assess what effects any differences would have on the comparison of microbial protein synthesis between diets.This study was conducted in conjunction with an in vitro experiment described by Carro and Miller (1997). Two 14-day incubation trials were carried out with the rumen simulation technique RUSITEC (Czerkawski and Breckenridge, 1977). The general incubation procedure was the one described by Czerkawski and Breckenridge (1977) and more details about the procedures of this experiment are given elsewhere (Carro and Miller, 1997).

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