Bacteria protein synthesis

Erythromycin Streptomyces erythreus Gram-positive bacteria Protein synthesis... 

The drug binds to the bacterial 50S ribosomal subunit and inhibits protein synthesis at the peptidyl transferase reaction. Because of the similarity of mammalian mitochondrial ribosomes to those of bacteria, protein synthesis in these organelles may be inhibited at high circulating chloramphenicol levels, producing bone marrow toxicity. 

Apphcations include ka olin clay dewatering, separation of fish oils from press Hquor, starch and gluten concentration, clarification of wet-process phosphoric acid, tar sands, and concentrations of yeast, bacteria, and fungi from growth media in protein synthesis (14). 

It has been known for some time that tetracyclines are accumulated by bacteria and prevent bacterial protein synthesis (Fig. 4). Furthermore, inhibition of protein synthesis is responsible for the bacteriostatic effect (85). Inhibition of protein synthesis results primarily from dismption of codon-anticodon interaction between tRNA and mRNA so that binding of aminoacyl-tRNA to the ribosomal acceptor (A) site is prevented (85). The precise mechanism is not understood. However, inhibition is likely to result from interaction of the tetracyclines with the 30S ribosomal subunit because these antibiotics are known to bind strongly to a single site on the 30S subunit (85). 

Ribosomes are ancient ribonucleoprotein complexes that are the sites of protein synthesis in living cells. Their core structures and fundamental functional mechanisms have been conserved throughout the three domains of life bacteria, archaea and eukaryotes. All ribosomes are organized into two subunits that are defined by their apparent sedimentation coefficient, measured in Svedberg units (S). There is a general... 

The lincosamides act by inhibiting protein synthesis in susceptible bacteria, causing death. 

MANY ANTIBIOTICS WORK BECAUSE THEY SELECTIVELY INHIBIT PROTEIN SYNTHESIS IN BACTERIA... 

The eytoplasm is a viscous fluid and contains within it systems of paramount importance. These are the nucleus, responsible for the genehc make-up of the cell, and the ribosomes, whieh are the site of protein synthesis, hi addihon are found granules of reserve material suehas polylydioxybutyric add, an energy reserve, and polyphosphate or volutin granules, the exact funchon of which has not yet been elucidated. The prokaiyohc nueleus or bacterial chromosome exists in the cytoplasm in the form of a loop and is not surrounded by a nuclear membrane. Bacteria cany other chromosomal elements episomes, which are portions of the main chromosome that have become isolated firm it, and plasmids, whieh may be called miniature chromosomes. These are small annular pieees of DNA whieh carry a limited amount of genetic information. 

Feedback inhibition of amino acid transporters by amino acids synthesized by the cells might be responsible for the well known fact that blocking protein synthesis by cycloheximide in Saccharomyces cerevisiae inhibits the uptake of most amino acids [56]. Indeed, under these conditions, endogenous amino acids continue to accumulate. This situation, which precludes studying amino acid transport in yeast in the presence of inhibitors of protein synthesis, is very different from that observed in bacteria, where amino acid uptake is commonly measured in the presence of chloramphenicol in order to isolate the uptake process from further metabolism of accumulated substances. In yeast, when nitrogen starvation rather than cycloheximide is used to block protein synthesis, this leads to very high uptake activity. This fact supports the feedback inhibition interpretation of the observed cycloheximide effect. 

There is evidence that both classes of anti-tumour agent act by inhibiting DNA synthesis as opposed to RNA or protein synthesis. Many agents which inhibit DNA synthesis cause lysis of lysogenic bacteria-X-rays, ultra-violet light, many carcinogens (3, 90). 

Protein synthesis is initiated by methionine as in archaea and not by formyl as in bacteria. 

Transcription and protein synthesis in the chloroplast can be inhibited by antibiotics because chloroplast ribosomes are similar in structure to those of bacteria. Chloroplast ribosomes are 70S in size, comprising a large 50S subunit (containing... 

The answer is b. (Hardman, p 1131.) Chloramphenicol inhibits protein synthesis in bacteria and, to a lesser extent, in eukaryotic cells. The drug binds reversibly to the. 505 ribosomal subunit and prevents attachment of aminoacybtransfer RNA (tRNA) to its binding site. The amino acid substrate is unavailable for peptidyl transferase and peptide bond formation. 

Ribosome inactivating cytotoxic protein that irreversibly inhibits protein synthesis in cells, causing cell death. It is a solid obtained from bacteria (Shigella dysenteriae). 

Ribosome activating cytotoxic proteins that irreversibly inhibit protein synthesis in cells, causing cell death. They are obtained from bacteria (Escherichia coli serotype 0157 H7). Verotoxin 1 is almost identical to shiga toxin (C16-A032) and differs only by a single amino acid. Verotoxin 2 has significant differences. 

Tetracyclines are a group of antibiotics derived from bacteria. Chlortet-racycline was isolated from Streptomyces aureofaciens and oxytetracycline from Streptomyces rimosus. Tetracychnes act by binding to receptors on the bacterial ribosome and inhibit bacterial protein synthesis. 

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