The so-called of Escherichia coli is a stable denatured conformer of the major isoacceptor

1986 ◽  
Vol 64 (4) ◽  
pp. 315-322 ◽  
Author(s):  
Thomas-Louis Tremblay ◽  
Jacques Lapointe
Keyword(s):  
Escherichia Coli ◽  
Salt Concentration ◽  
Growth Conditions ◽  
Major Peak ◽  
E Coli ◽  
Minor Peak ◽  
Trna Species ◽  
Resolution Analysis ◽  
A Minor ◽  
Two Peaks

A single peak of tRNAGlu is obtained upon chromatography of unfractionated tRNA from Escherichia coli on DEAE-Sephadex A-50 if this tRNA was previously renatured, whereas two peaks of tRNAGlu are resolved if the sample chromatographed is a mixture of native (renatured) and denatured tRNA. Higher resolution analysis of native E. coli tRNA by RPC-5 chromatography showed that most of the tRNAGlu is present in one peak, eluted shortly after a minor peak containing about or less than 5% of the total amount of tRNAGlu; these two peaks were also observed with commercially available tRNAGlu purified from E. coli. When denatured, the tRNAGlu present in each of these two peaks was eluted from the RPC-5 column at a much lower salt concentration. The properties of the denatured conformers obtained from native tRNAGlu present in the major and minor peaks, and the variation, with growth conditions of E. coli, in the relative amount of tRNAGlu in the minor peak suggest that the tRNAGlu present in the minor peak is an undermodified form of the tRNAGlu present in the major peak. This [Formula: see text] (or [Formula: see text] when modified in the anticodon) would then be the only tRNA species acceptor of glutamate in E. coli.

scholarly journals Dynamique De La Population De La Crevette D’eau Douce Atya Scabra (Leach, 1815) (Decapoda: Atyidae) Dans La Rivière Bia, Région Du Sud-Comoé (Côte d’Ivoire)

2017 ◽  
Vol 13 (12) ◽  
pp. 84
Author(s):  
Vincent Kadjo ◽  
Assoi O. Etchian ◽  
Jean-Noel Yapi ◽  
Atcho Otchoumou ◽  
Aka Jean-Paul Agnissan ◽  
...  
Keyword(s):  
Survival Rate ◽  
Growth Performance ◽  
Normal Distribution ◽  
Performance Index ◽  
Total Mortality ◽  
Major Peak ◽  
Minor Peak ◽  
Rational Management ◽  
A Minor ◽  
Two Peaks

The parameters of growth, mortality, the exploitation and the recruitment of Atya scabra (Leach, 1815) as traditionally fished in the Bia river, were studied. These parameters were determined from the size frequencies by the FiSAT II software. The results obtained at the specimens of Aboisso were:= 156,45 mm, K = 1,50 year -1, Φ' = 4,56, Z = 5,72 year -1, M = 1,48 year -1, F = 4,24 year -1 and E = 0,74 year -1. In Biaka, theestimated values were: L = 140,7 mm, K = 0,68 year -1, Φ' = 4,13, Z = 1,52year -1, M = 0,91 year -1, F = 0,61 year -1 and E = 0,40 year -1 . Aboisso specimens have a higher growth performance index (Φ') than Biaka's and a weak longevity (tmax = 2 years) compared to Biaka (tmax = 4.41 years). Shrimps are under exploited in the locality of Biaka (E 0.5). Total mortality is higher in Aboisso than in Biaka. However, the survival rate recorded in Aboisso (S = 0.003 years) is lower than that of Biaka (S = 0.22 years). Recruitment is continuous throughout the year, with two peaks (a major peak in September and a minor peak in February) in Aboisso. As for Biaka, the presence of a normal distribution indicates that recruitment is single. These results will serve as a database for rational management of A. scabra.

scholarly journals A Rhodobacter sphaeroides Protein Mechanistically Similar to Escherichia coli DksA Regulates Photosynthetic Growth

mBio ◽  
2014 ◽  
Vol 5 (3) ◽  
Author(s):  
Christopher W. Lennon ◽  
Kimberly C. Lemmer ◽  
Jessica L. Irons ◽  
Max I. Sellman ◽  
Timothy J. Donohue ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Structure Function ◽  
Rhodobacter Sphaeroides ◽  
Fatty Acid Content ◽  
Regulatory Protein ◽  
Growth Conditions ◽  
Globular Domain ◽  
Content Type ◽  
E Coli

ABSTRACTDksA is a global regulatory protein that, together with the alarmone ppGpp, is required for the “stringent response” to nutrient starvation in the gammaproteobacteriumEscherichia coliand for more moderate shifts between growth conditions. DksA modulates the expression of hundreds of genes, directly or indirectly. Mutants lacking a DksA homolog exhibit pleiotropic phenotypes in other gammaproteobacteria as well. Here we analyzed the DksA homolog RSP2654 in the more distantly relatedRhodobacter sphaeroides, an alphaproteobacterium. RSP2654 is 42% identical and similar in length toE. coliDksA but lacks the Zn finger motif of theE. coliDksA globular domain. Deletion of the RSP2654 gene results in defects in photosynthetic growth, impaired utilization of amino acids, and an increase in fatty acid content. RSP2654 complements the growth and regulatory defects of anE. colistrain lacking thedksAgene and modulates transcriptionin vitrowithE. coliRNA polymerase (RNAP) similarly toE. coliDksA. RSP2654 reduces RNAP-promoter complex stabilityin vitrowith RNAPs fromE. coliorR. sphaeroides, alone and synergistically with ppGpp, suggesting that even though it has limited sequence identity toE. coliDksA (DksAEc), it functions in a mechanistically similar manner. We therefore designate the RSP2654 protein DksARsp. Our work suggests that DksARsphas distinct and important physiological roles in alphaproteobacteria and will be useful for understanding structure-function relationships in DksA and the mechanism of synergy between DksA and ppGpp.IMPORTANCEThe role of DksA has been analyzed primarily in the gammaproteobacteria, in which it is best understood for its role in control of the synthesis of the translation apparatus and amino acid biosynthesis. Our work suggests that DksA plays distinct and important physiological roles in alphaproteobacteria, including the control of photosynthesis inRhodobacter sphaeroides. The study of DksARsp, should be useful for understanding structure-function relationships in the protein, including those that play a role in the little-understood synergy between DksA and ppGpp.

scholarly journals The Escherichia coli cysG promoter belongs to the ‘extended −10’ class of bacterial promoters

1993 ◽  
Vol 296 (3) ◽  
pp. 851-857 ◽  
Author(s):  
T Belyaeva ◽  
L Griffiths ◽  
S Minchin ◽  
J Cole ◽  
S Busby
Keyword(s):  
Escherichia Coli ◽  
Point Mutations ◽  
Growth Conditions ◽  
Upstream Region ◽  
E Coli ◽  
Run Off ◽  
A Site ◽  
Specific Sequences

The Escherichia coli cysG promoter has been subcloned and shown to function constitutively in a range of different growth conditions. Point mutations identify the -10 hexamer and an important 5′-TGN-3′ motif immediately upstream. The effects of different deletions suggest that specific sequences in the -35 region are not essential for the activity of this promoter in vivo. This conclusion was confirmed by in vitro run-off transcription assays. The DNAase I footprint of RNA polymerase at the cysG promoter reveals extended protection upstream of the transcript start, and studies with potassium permanganate as a probe suggest that the upstream region is distorted in open complexes. Taken together, the results show that the cysG promoter belongs to the ‘extended -10’ class of promoters, and the base sequence is similar to that of the P1 promoter of the E. coli galactose operon, another promoter in this class. In vivo, messenger initiated at the cysG promoter appears to be processed by cleavage at a site 41 bases downstream from the transcript start point.

Some aspects of the ecology of bagrid catfishes in a southern Nigerian river

1991 ◽  
Vol 7 (2) ◽  
pp. 221-232 ◽  
Author(s):  
George Idodo-Umeh ◽  
Reginald Victor
Keyword(s):  
Spatial Distribution ◽  
Species Composition ◽  
Rainy Season ◽  
Major Peak ◽  
Fish Yield ◽  
Southern Nigeria ◽  
Minor Peak ◽  
A Minor ◽  
Principal Species ◽  
Dry And Rainy Seasons

ABSTRACTSome aspects of the ecology of bagrid catfishes in River Ase, southern Nigeria were studied for a period of two years. Nine species of Bagridae were recorded and these accounted for 15.0% of the number and 24.4% of the weight of all fish captured. Chrysichthys nigrodigitatus and Chrysichthys auratus longifilis were the principal species. C. nigrodigitatus was a rainy season species, while C. auratus longifilis was abundant in both dry and rainy seasons. Both species showed a major peak in catches between 0600 and 0900 h. C. nigrodigitatus exhibited a minor peak in catches between 1500 and 2100h, while C. auratus longifilis showed a minor peak between 1500 and 1800h. The spatial distribution of C. nigrodigitatus and C. auratus longifilis populations was heterogeneous. Bagrid fishes were an important component in the fish yield of the study river and its species composition has been compared with those of other Nigerian waters. The distribution and abundance of C. nigrodigitatus and C. auratus longifilis are discussed in detail.

scholarly journals Aerobic Fermentation of d-Glucose by an Evolved Cytochrome Oxidase-Deficient Escherichia coli Strain

2008 ◽  
Vol 74 (24) ◽  
pp. 7561-7569 ◽  
Author(s):  
Vasiliy A. Portnoy ◽  
Markus J. Herrgård ◽  
Bernhard Ø. Palsson
Keyword(s):  
Escherichia Coli ◽  
Oxygen Uptake ◽  
Growth Conditions ◽  
Aerobic Growth ◽  
Acid Fermentation ◽  
Mixed Acid Fermentation ◽  
E Coli ◽  
Knockout Strain ◽  
Mixed Acid ◽  
Cytochrome Oxidases

ABSTRACT Fermentation of glucose to d-lactic acid under aerobic growth conditions by an evolved Escherichia coli mutant deficient in three terminal oxidases is reported in this work. Cytochrome oxidases (cydAB, cyoABCD, and cbdAB) were removed from the E. coli K12 MG1655 genome, resulting in the ECOM3 (E. coli cytochrome oxidase mutant) strain. Removal of cytochrome oxidases reduced the oxygen uptake rate of the knockout strain by nearly 85%. Moreover, the knockout strain was initially incapable of growing on M9 minimal medium. After the ECOM3 strain was subjected to adaptive evolution on glucose M9 medium for 60 days, a growth rate equivalent to that of anaerobic wild-type E. coli was achieved. Our findings demonstrate that three independently adaptively evolved ECOM3 populations acquired different phenotypes: one produced lactate as a sole fermentation product, while the other two strains exhibited a mixed-acid fermentation under oxic growth conditions with lactate remaining as the major product. The homofermenting strain showed a d-lactate yield of 0.8 g/g from glucose. Gene expression and in silico model-based analyses were employed to identify perturbed pathways and explain phenotypic behavior. Significant upregulation of ygiN and sodAB explains the remaining oxygen uptake that was observed in evolved ECOM3 strains. E. coli strains produced in this study showed the ability to produce lactate as a fermentation product from glucose and to undergo mixed-acid fermentation during aerobic growth.

Relationship of growth conditions to desiccation tolerance of Salmonella enterica, Escherichia coli, and Listeria monocytogenes

2021 ◽  
Author(s):  
Rachel K Streufert ◽  
Susanne E Keller ◽  
Joelle K Salazar
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Desiccation Tolerance ◽  
Salmonella Enterica ◽  
Growth Conditions ◽  
Initial Population ◽  
Desiccation Resistance ◽  
E Coli ◽  
Solid Media ◽  
Agar Media

Growth on solid media as sessile cells is believed to increase the desiccation tolerance of Salmonella enterica . However, the reasons behind increased resistance have not been well explored. In addition, the same effect has not been examined for other foodborne pathogens such as pathogenic Escherichia coli or Listeria monocytogenes . The purpose of this research was two-fold: first, to determine the role of oxygenation during growth on the desiccation resistance of S. enterica , E. coli , and L. monocytogenes , and second, to determine the effect of sessile versus planktonic growth on the desiccation resistance of these pathogens. Three different serotypes each of Salmonella , E. coli , and L. monocytogenes were cultured in trypticase soy broth with 0.6% yeast extract (TSBYE), with (aerobic) shaking or on TSBYE with agar (TSAYE) under either aerobic or anaerobic conditions and harvested in stationary phase. After adding cell suspensions to cellulose filter disks, pathogen survival was determined by enumeration at 0 and after drying for 24 h. Results showed statistical differences in harvested initial populations prior to drying (0 h). For Salmonella , a correlation was found between high initial population and greater survival on desiccation (p = 0.05). In addition, statistical differences (p ≤ 0.05) between survival based on growth type were identified. However, differences found were not the same for the three pathogens, or between their serotypes. In general, Salmonella and E. coli desiccation resistance followed the pattern of aerobic agar media ≥ liquid media ≥ anaerobic agar media. For L. monocytogenes serotypes, resistance to desiccation was not statistically different based on mode of growth. These results indicate growth on solid media under aerobic conditions is not always necessary for optimal desiccation survival but may be beneficial when the desiccation resistance of the test serotype is unknown.

scholarly journals Glutathionylspermidine metabolism in Escherichia coli

1995 ◽  
Vol 312 (2) ◽  
pp. 465-469 ◽  
Author(s):  
K Smith ◽  
A Borges ◽  
M R Ariyanayagam ◽  
A H Fairlamb
Keyword(s):  
Escherichia Coli ◽  
Glutathione Reductase ◽  
Growth Conditions ◽  
Anaerobic Growth ◽  
Growth Phases ◽  
Total Glutathione ◽  
Apparent Lack ◽  
E Coli ◽  
Catalytic Constant ◽  
Glutathione Disulphide

Intracellular levels of glutathione and glutathionylspermidine conjugates have been measured throughout the growth phases of Escherichia coli. Glutathionylspermidine was present in mid-log-phase cells, and under stationary and anaerobic growth conditions accounted for 80% of the total glutathione content. N1,N8-bis(glutathionyl)spermidine (trypanothione) was undetectable under all growth conditions. The catalytic constant kcat/Km of recombinant E. coli glutathione reductase for glutathionylspermidine disulphide was approx. 11,000-fold lower than that for glutathione disulphide. The much higher catalytic constant for the mixed disulphide of glutathione and glutathionylspermidine (11% that of GSSG), suggests a possible explanation for the low turnover of trypanothione disulphide by E. coli glutathione reductase, given the apparent lack of a specific glutathionylspermidine disulphide reductase in E. coli.

scholarly journals Escherichia coli NsrR Regulates a Pathway for the Oxidation of 3-Nitrotyramine to 4-Hydroxy-3-Nitrophenylacetate

2008 ◽  
Vol 190 (18) ◽  
pp. 6170-6177 ◽  
Author(s):  
Linda D. Rankin ◽  
Diane M. Bodenmiller ◽  
Jonathan D. Partridge ◽  
Shirley F. Nishino ◽  
Jim C. Spain ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Physiological Role ◽  
Growth Conditions ◽  
Growth Defect ◽  
E Coli ◽  
Mutant Phenotypes ◽  
Culture Supernatants ◽  
Chip Chip

ABSTRACT Chromatin immunoprecipitation and microarray (ChIP-chip) analysis showed that the nitric oxide (NO)-sensitive repressor NsrR from Escherichia coli binds in vivo to the promoters of the tynA and feaB genes. These genes encode the first two enzymes of a pathway that is required for the catabolism of phenylethylamine (PEA) and its hydroxylated derivatives tyramine and dopamine. Deletion of nsrR caused small increases in the activities of the tynA and feaB promoters in cultures grown on PEA. Overexpression of nsrR severely retarded growth on PEA and caused a marked repression of the tynA and feaB promoters. Both the growth defect and the promoter repression were reversed in the presence of a source of NO. These results are consistent with NsrR mediating repression of the tynA and feaB genes by binding (in an NO-sensitive fashion) to the sites identified by ChIP-chip. E. coli was shown to use 3-nitrotyramine as a nitrogen source for growth, conditions which partially induce the tynA and feaB promoters. Mutation of tynA (but not feaB) prevented growth on 3-nitrotyramine. Growth yields, mutant phenotypes, and analyses of culture supernatants suggested that 3-nitrotyramine is oxidized to 4-hydroxy-3-nitrophenylacetate, with growth occurring at the expense of the amino group of 3-nitrotyramine. Accordingly, enzyme assays showed that 3-nitrotyramine and its oxidation product (4-hydroxy-3-nitrophenylacetaldehyde) could be oxidized by the enzymes encoded by tynA and feaB, respectively. The results suggest that an additional physiological role of the PEA catabolic pathway is to metabolize nitroaromatic compounds that may accumulate in cells exposed to NO.

Evaluation of biofilm performance as a protective barrier against biocorrosion using an enzyme electrode

2011 ◽  
Vol 64 (8) ◽  
pp. 1736-1742 ◽  
Author(s):  
S. Soleimani ◽  
B. Ormeci ◽  
O. B. Isgor ◽  
S. Papavinasam
Keyword(s):  
Escherichia Coli ◽  
Growth Conditions ◽  
Microbiologically Influenced Corrosion ◽  
Simple Method ◽  
E Coli ◽  
Concrete Deterioration ◽  
Protective Barrier ◽  
Microbial Biofilms ◽  
Short Time ◽  
Selection Of

Sulfide is known to be an important factor in microbiologically influenced corrosion (MIC) of metals and concrete deterioration in wastewater treatment structures and sewer pipelines. A sulfide biosensor was used to determine the effectiveness of Escherichia coli DH5α biofilm as a protective barrier against MIC. The biofilm was shown to be effective in protecting surfaces from sulfide and helping to reduce MIC using amperometric measurements. The results also indicated that the growth conditions of E. coli DH5α may have an impact on the performance of the biofilm as a sulfide barrier. The simple method provided in this work enables the comparison of several microbial biofilms and selection of the ones with potential to prevent MIC in a relatively short time.

scholarly journals Global Lysine Acetylation in Escherichia coli Results from Growth Conditions That Favor Acetate Fermentation

2019 ◽  
Vol 201 (9) ◽  
Author(s):  
Birgit Schilling ◽  
Nathan Basisty ◽  
David G. Christensen ◽  
Dylan Sorensen ◽  
James S. Orr ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Enzyme Activity ◽  
Regulatory Mechanism ◽  
Growth Conditions ◽  
Lysine Acetylation ◽  
Label Free ◽  
Content Type ◽  
E Coli ◽  
Regulatory Mode ◽  
Specific Sugar

ABSTRACT Lysine acetylation is thought to provide a mechanism for regulating metabolism in diverse bacteria. Indeed, many studies have shown that the majority of enzymes involved in central metabolism are acetylated and that acetylation can alter enzyme activity. However, the details regarding this regulatory mechanism are still unclear, specifically with regard to the signals that induce lysine acetylation. To better understand this global regulatory mechanism, we profiled changes in lysine acetylation during growth of Escherichia coli on the hexose glucose or the pentose xylose at both high and low sugar concentrations using label-free mass spectrometry. The goal was to see whether lysine acetylation differed during growth on these two different sugars. No significant differences, however, were observed. Rather, the initial sugar concentration was the principal factor governing changes in lysine acetylation, with higher sugar concentrations causing more acetylation. These results suggest that acetylation does not target specific metabolic pathways but rather simply targets accessible lysines, which may or may not alter enzyme activity. They further suggest that lysine acetylation principally results from conditions that favor accumulation of acetyl phosphate, the principal acetate donor in E. coli. IMPORTANCE Bacteria alter their metabolism in response to nutrient availability, growth conditions, and environmental stresses using a number of different mechanisms. One is lysine acetylation, a posttranslational modification known to target many metabolic enzymes. However, little is known about this regulatory mode. We investigated the factors inducing changes in lysine acetylation by comparing growth on glucose and xylose. We found that the specific sugar used for growth did not alter the pattern of acetylation; rather, the amount of sugar did, with more sugar causing more acetylation. These results imply that lysine acetylation is a global regulatory mechanism that is responsive not to the specific carbon source per se but rather to the accumulation of downstream metabolites.

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