Biomaterial Database

Chloramphenicol-induced changes in the synthesis of ribosomal, transfer, and messenger ribonucleic acids in Escherichia coli B/r. 1977

V Shen, and H Bremer

The synthesis of ribosomal ribonucleic acid (rRNA), transfer RNA (tRNA) and messenger RNA (mRNA) was measured in Escherichia coli B/r after the addition of 100 mug of chloramphenicol (CAM) per ml to cultures growing either in one of three minimal media (succinate, glycerol, or glucose) or in one of the same three media supplemented with 20 amino acids. (i) During CAM treatment, rRNA and tRNA were synthesized in the same relative proportions (85:15) as during exponential growth. The faster accumulation of tRNA relative to rRNA in CAM was due to a decreased stability of rRNA that is synthesized in the presence of or immediately before the addition of CAM. (ii) CAM stimulated the synthesis of rRNA and tRNA two- to eightfold. The results fell into two groups; one group was from studies done in minimal media and the other was from amino acid-supplemented media. In each group the stimulation decreased with increasing growth rate of the culture during exponential growth before the addition of CAM; however, the stimulation in minimal media was lower than that in amino acid-supplemented media. (iii) CAM caused an increase in the proportion of rRNA and tRNA synthesis and a corresponding decrease in the proportion of mRNA synthesis. In minimal media, the residual proportion of mRNA synthesis after CAM treatment was 10 to 15% of total RNA synthesis; in amino acid-supplemented media this proportion was 0 to 10%. In either case, the residual proportion of mRNA synthesis was independent of the proportions observed during exponential growth in these media. (iv) The absolute rate of mRNA synthesis decreased severalfold with the addition of CAM; i.e., the rate of synthesis of rRNA and tRNA was increased at the expense of mRNA synthesis. (v) During exponential growth, the fraction of the instantaneous rate of total RNA synthesis that corresponds to mRNA is a function of both the growth rate and the presence or absence of amino acids in the growth medium: in the absence of amino acids, this fraction decreased with increasing growth rate; in the presence of amino acids, the fraction increased slightly with growth rate. These results are consistent with a regulation of rRNA and tRNA synthesis at the transcriptional level, e.g., with a CAM-induced increase in the affinity of RNA polymerase for the rRNA and tRNA promoters. The results also suggest the occurrence of a regulation of RNA polymerase enzyme activity, i.e., of an activation of RNA polymerase that is inactive during exponential growth. A distinction between these alternatives requires measurements of the rRNA chain growth rates during CAM treatment.

UI	MeSH Term	Description	Entries
D009693	Nucleic Acid Hybridization	Widely used technique which exploits the ability of complementary sequences in single-stranded DNAs or RNAs to pair with each other to form a double helix. Hybridization can take place between two complimentary DNA sequences, between a single-stranded DNA and a complementary RNA, or between two RNA sequences. The technique is used to detect and isolate specific sequences, measure homology, or define other characteristics of one or both strands. (Kendrew, Encyclopedia of Molecular Biology, 1994, p503)	Genomic Hybridization,Acid Hybridization, Nucleic,Acid Hybridizations, Nucleic,Genomic Hybridizations,Hybridization, Genomic,Hybridization, Nucleic Acid,Hybridizations, Genomic,Hybridizations, Nucleic Acid,Nucleic Acid Hybridizations
D002701	Chloramphenicol	An antibiotic first isolated from cultures of Streptomyces venequelae in 1947 but now produced synthetically. It has a relatively simple structure and was the first broad-spectrum antibiotic to be discovered. It acts by interfering with bacterial protein synthesis and is mainly bacteriostatic. (From Martindale, The Extra Pharmacopoeia, 29th ed, p106)	Cloranfenicol,Kloramfenikol,Levomycetin,Amphenicol,Amphenicols,Chlornitromycin,Chlorocid,Chloromycetin,Detreomycin,Ophthochlor,Syntomycin
D004269	DNA, Bacterial	Deoxyribonucleic acid that makes up the genetic material of bacteria.	Bacterial DNA
D004591	Electrophoresis, Polyacrylamide Gel	Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.	Polyacrylamide Gel Electrophoresis,SDS-PAGE,Sodium Dodecyl Sulfate-PAGE,Gel Electrophoresis, Polyacrylamide,SDS PAGE,Sodium Dodecyl Sulfate PAGE,Sodium Dodecyl Sulfate-PAGEs
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D012329	RNA, Bacterial	Ribonucleic acid in bacteria having regulatory and catalytic roles as well as involvement in protein synthesis.	Bacterial RNA
D012333	RNA, Messenger	RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.	Messenger RNA,Messenger RNA, Polyadenylated,Poly(A) Tail,Poly(A)+ RNA,Poly(A)+ mRNA,RNA, Messenger, Polyadenylated,RNA, Polyadenylated,mRNA,mRNA, Non-Polyadenylated,mRNA, Polyadenylated,Non-Polyadenylated mRNA,Poly(A) RNA,Polyadenylated mRNA,Non Polyadenylated mRNA,Polyadenylated Messenger RNA,Polyadenylated RNA,RNA, Polyadenylated Messenger,mRNA, Non Polyadenylated
D012335	RNA, Ribosomal	The most abundant form of RNA. Together with proteins, it forms the ribosomes, playing a structural role and also a role in ribosomal binding of mRNA and tRNAs. Individual chains are conventionally designated by their sedimentation coefficients. In eukaryotes, four large chains exist, synthesized in the nucleolus and constituting about 50% of the ribosome. (Dorland, 28th ed)	Ribosomal RNA,15S RNA,RNA, 15S
D012343	RNA, Transfer	The small RNA molecules, 73-80 nucleotides long, that function during translation (TRANSLATION, GENETIC) to align AMINO ACIDS at the RIBOSOMES in a sequence determined by the mRNA (RNA, MESSENGER). There are about 30 different transfer RNAs. Each recognizes a specific CODON set on the mRNA through its own ANTICODON and as aminoacyl tRNAs (RNA, TRANSFER, AMINO ACYL), each carries a specific amino acid to the ribosome to add to the elongating peptide chains.	Suppressor Transfer RNA,Transfer RNA,tRNA,RNA, Transfer, Suppressor,Transfer RNA, Suppressor,RNA, Suppressor Transfer
D013997	Time Factors	Elements of limited time intervals, contributing to particular results or situations.	Time Series,Factor, Time,Time Factor