Inhibition of uridine 5′-diphosphate-N-acetylmuramyl-L-alanine synthetase by β-chloro-L-alanine in Escherichia coli

1982 ◽  
Vol 28 (6) ◽  
pp. 654-659 ◽  
Author(s):  
Edward E. Ishiguro
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Diaminopimelic Acid ◽  
Alanine Racemase ◽  
Uridine Diphosphate ◽  
Amino Acid Deprivation ◽  
Intact Cells ◽  
Low Concentration ◽  
Low Concentrations ◽  
Precursor Synthesis

The synthesis of the nucleotide precursors for peptidoglycan is regulated by the relA gene in Escherichia coli. Thus, nucleotide precursors labeled with [3H]diaminopimelic acid accumulated in a relA strain but not in an isogenic relA+ strain during amino acid deprivation. Furthermore, nucleotide precursor synthesis was relaxed in the amino acid deprived relA+ strain by treatment with chloramphenicol. Uridine diphosphate-N-acetylmuramyl-pentapeptide (UDP-MurNAc-pentapeptide) was the major component accumulated during the relaxed synthesis of nucleotide precursors in both relA+ and relA strains. The effect of β-chloro-L-alanine (CLA) on the relaxed synthesis of nucleotide precursors for peptidoglycan was determined. At a low concentration (0.0625 mM) CLA inhibited the synthesis of UDP-MurNAc-pentapeptide and caused the accumulation of UDP-MurNAc-tripeptide. Thus, low concentrations of CLA probably inhibited alanine racemase, as reported previously. Higher concentrations of CLA also inhibited an earlier step in nucleotide precursor synthesis. This was shown to be due to the inhibition of UDP-MurNAc-L-alanine synthetase by CLA. CLA inhibited the activity of this enzyme in cell-free extracts as well as in intact cells.

scholarly journals Early changes in the messenger ribonucleic acid concentration of amino acid-starved cells of Escherichia coli are not dependent on the state of the rel gene

1974 ◽  
Vol 144 (3) ◽  
pp. 605-606
Author(s):  
John E. M. Midgley ◽  
R. John Smith
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Acid Concentration ◽  
Ribonucleic Acid ◽  
The State ◽  
Amino Acid Deprivation ◽  
Messenger Ribonucleic Acid

Measurements of the concentration of mRNA in rel+and rel-strains of Escherichia coli shortly after the imposition of amino acid deprivation indicate that there is a temporary fall in the amount of this fraction relative to the total cellular RNA.

scholarly journals Antibiotic-resistantEscherichia coliin market pigs in 1956–1979: the emergence of organisms with plasmid-borne trimethoprim resistance

1980 ◽  
Vol 84 (3) ◽  
pp. 467-477 ◽  
Author(s):  
H. Williams Smith
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Considerable Proportion ◽  
Low Concentration ◽  
E Coli ◽  
Low Concentrations

SUMMARYSurveys conducted since 1956 on the antibiotic resistance of theEscherichia coliin faecal specimens from pigs entering Chelmsford Market have revealed that despite the implementation of the Swann Report in 1971 pigs are still an enormous reservior of tetracycline-resistantE. coliwith conjugative ability.Increasingly large amounts ofE. coliresistant to streptomycin and sulphonamides were found in specimens examined in recent years unitl in 1979 the amounts present approached those of tetracycline-resistant organisms.E. coliresistant to chloramphenicol, ampicillin, neomycin, furazolidone or spectinomycin were present, usually in low concentration, in a considerable proportion of the specimens at each yearly examination but the concentration and incidence of these organisms showed no obvious sign of increasing with time. Much of this resistance, except to furazolidone, was of the transferable type.Until 1979 the incidence of faecal specimens containing trimethoprim-resistantE. coliwas very low. It increased significantly in that year, most of the resistance being plasmid-, or possibly transposon-determined.The result of surveys performed in a Cambridgeshire market in 1978 and 1979, which showed that a high proportion of faecal specimens contained low concentrations of trimethoprim-resistantE. coli, in general resembled those of the corresponding Chelmsford surveys, suggesting that all the Chelmsford surveys may have accurately reflected the position in the national pig herd.

scholarly journals The control of ribonucleic acid synthesis in bacteria. Polymerization rates for ribonucleic acids in amino acid-starved relaxed and stringent auxotrophs of Escherichia coli

1972 ◽  
Vol 128 (5) ◽  
pp. 1021-1031 ◽  
Author(s):  
W. J. H. Gray ◽  
T. G. Vickers ◽  
J. E. M. Midgley
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Normal Growth ◽  
Acid Synthesis ◽  
Amino Acid Deprivation ◽  
Ribonucleic Acids ◽  
Rate Of Polymerization ◽  
Chain Polymerization ◽  
Multiple Amino Acid ◽  
Nucleotide Bases

Polymerization rates of newly formed chains of various RNA fractions were measured in Escherichia coli CP78 (RCstr) and CP79 (RCrel) multiple amino acid auxotrophs, deprived of four amino acids essential for growth. Immediately after the onset of severe amino acid deprivation, in RCstr strains the rate of labelling of RNA by exogenous nucleotide bases was greatly diminished. At first, the initiation of new RNA chains declined faster than the rate of polymerization in RCstr organisms, but as starvation proceeded the rate of polymerization was eventually lowered to about 10% of that found during normal growth. In strain CP79 (RCrel), on the other hand, chain-polymerization rates were unaffected by amino acid withdrawal. Artificial depletion of the intracellular purine nucleotide pools in RCstr or RCrel strains by trimethoprim, before the onset of amino acid deprivation, showed that in the RCstr, but not the RCrel strain, amino acid withdrawal gave rise to an inability of the cells to utilize exogenously supplied purine or pyrimidine bases for RNA synthesis. During a prolonged starvation, the observed 100-fold decrease in the total rate of incorporation of exogenous nucleotide bases into the RNA of RCstr organisms was ascribed to a combination of a tenfold decrease in the overall rate of RNA chain polymerization, at least a fivefold decrease in the ability of the cells to utilize exogenous bases and a preferential inhibition of initiation of stable RNA chains. None of these changes occurred in the corresponding RCrel strain.

scholarly journals Effect on solute size on diffusion rates through the transmembrane pores of the outer membrane of Escherichia coli.

1981 ◽  
Vol 77 (2) ◽  
pp. 121-135 ◽  
Author(s):  
H Nikaido ◽  
E Y Rosenberg
Keyword(s):  
Escherichia Coli ◽  
Outer Membrane ◽  
Specific Class ◽  
Wild Type ◽  
Intact Cells ◽  
E Coli ◽  
Low Concentrations ◽  
Transmembrane Pores ◽  
Diffusion Rates ◽  
Type Strains

Nutrients usually cross the outer membrane of Escherichia coli by diffusion through water-filled channels surrounded by a specific class of protein, porins. In this study, the rates of diffusion of hydrophilic nonelectrolytes, mostly sugars and sugar alcohols, through the porin channels were determined in two systems, (a) vesicles reconstituted from phospholipids and purified porin and (b) intact cells of mutant strains that produce many fewer porin molecules than wild-type strains. The diffusion rates were strongly affected by the size of the solute, even when the size was well within the "exclusion limit" of the channel. In both systems, hexoses and hexose disaccharides diffused through the channel at rates 50-80% and 2-4%, respectively, of that of a pentose, arabinose. Application of the Renkin equation to these data led to the estimate that the pore radius is approximately 0.6 nm, if the pore is assumed to be a hollow cylinder. The results of the study also show that the permeability of the outer membrane of the wild-type E. coli cell to glucose and lactose can be explained by the presence of porin channels, that a significant fraction of these channels must be functional or "open" under our conditions of growth, and that even 10(5) channels per cell could become limiting when E. coli tries to grow at a maximal rate on low concentrations of slowly penetrating solutes, such as disaccharides.

scholarly journals Amino acid deprivation and its effect on mating ability inEscherichia coliK12

1966 ◽  
Vol 8 (1) ◽  
pp. 115-118 ◽  
Author(s):  
K. W. Fisher
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Deprivation ◽  
Mating Ability ◽  
Chromosome Transfer ◽  
E Coli ◽  
Donor Cells ◽  
Relationship Of ◽  
The Relationship

The conclusion by Suit, Matney, Doudney & Billen (1964) that Hfr donor cells ofEscherichia coliK12, starved of required amino acids can mate, has been re-examined. It appears that their conclusion is not valid and that apparent fertility of amino-acid starved cells is due to cross-feeding by the F−cells. The relationship of this result to the alternative mechanisms for chromosome transfer inE. coliis discussed.

scholarly journals Infection of Macrophage-Like THP-1 Cells withMycobacterium avium Results in a Decrease in Their Ability to Phosphorylate Nucleolin

2000 ◽  
Vol 68 (6) ◽  
pp. 3121-3128 ◽  
Author(s):  
Rodolfo C. Garcia ◽  
Elena Banfi ◽  
Maria G. Pittis
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Gel Electrophoresis ◽  
Host Response ◽  
Soluble Fraction ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Amino Acid Sequencing ◽  
Intact Cells ◽  
Infected Cells

ABSTRACT This study of the phosphorylation ability of macrophage-like cells upon infection with Mycobacterium avium was undertaken to establish potential targets of the interference with host response mechanisms. Cytosolic and membrane fractions from noninfected and infected cells were incubated with [γ-32P]ATP, in the presence of Mg2+ and the absence of Ca2+, and the patterns of phosphoproteins synthesized were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Lower levels of a 110-kDa phosphoprotein were observed in association with cytosolic fractions from mycobacterium-infected cells compared to noninfected cells or cells treated with lipopolysaccharide or having ingestedEscherichia coli or killed M. avium. The 110-kDa phosphoprotein was present in the soluble fraction (230,000 ×g supernatant) after the kinase incubation, from where it was partially purified and identified as phosphonucleolin by amino acid sequencing. The decrease in nucleolin phosphorylation observed was not related to changes in the cytosolic or membrane levels of this protein, and was detected also in the cytosolic fraction of32P-labeled intact cells.

scholarly journals ARGININE-RICH PROTEINS OF POLYMORPHONUCLEAR LEUKOCYTE LYSOSOMES

1968 ◽  
Vol 127 (5) ◽  
pp. 927-941 ◽  
Author(s):  
H. I. Zeya ◽  
J. K. Spitznagel
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Staphylococcus Aureus ◽  
Amino Acid ◽  
Pathogenic Bacteria ◽  
Aromatic Amino Acids ◽  
Electrophoretic Mobilities ◽  
Low Concentrations ◽  
Different Cultures ◽  
Very High

The cationic antibacterial proteins of rabbit PMN lysosomes have been resolved into at least five subfractions. Each of these showed substantial selectivity in its antibacterial action against several pathogenic bacteria, including two smooth and two rough Escherichia coli strains, three Staphylococcus aureus strains, one S. albus, three proteus species and four different cultures of streptococcus. Each of the subfractions possesses a different electrophoretic mobility. Amino acid analyses of the three most cationic components revealed high contents of arginine consistent with their relative electrophoretic mobilities and very high arginine to lysine ratios. Aromatic amino acids were present in very low concentrations in these proteins and their light absorption at 2800 A was correspondingly weak. The evidence of antibacterial specificity, along with marked differences in the arginine-lysine ratios, shows that the cationic antibacterial components of rabbit PMN lysosomes are biologically and chemically heterogeneous.

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