scholarly journals Role of the Cold-Box Region in the 5′ Untranslated Region of the cspA mRNA in Its Transient Expression at Low Temperature in Escherichia coli

1998 ◽  
Vol 180 (1) ◽  
pp. 90-95 ◽  
Author(s):  
Li Fang ◽  
Yan Hou ◽  
Masayori Inouye
Keyword(s):  
Escherichia Coli ◽  
Low Temperature ◽  
Untranslated Region ◽  
Cold Shock ◽  
Wild Type ◽  
Mrna Stabilization ◽  
High Level ◽  
Cold Box ◽  
In Cells

ABSTRACT Upon temperature downshift, a group of proteins called cold shock proteins, such as CspA, CspB, and CsdA, are transiently induced inEscherichia coli. However, when the 5′ untranslated region (5′ UTR) of cspA mRNA is overproduced at low temperature, the expression of cold shock genes is prolonged or derepressed. It has been proposed that this effect is due to highly conserved 11-base sequences designated the “cold box” existing in the 5′ UTRs ofcspA, cspB, and csdA. Here, we demonstrate that the overproduction of the 5′ UTR of not onlycspA but also cspB and csdA mRNAs causes derepression of all three genes at the same time. Conversely, when the cold-box region was deleted from the cspA 5′ UTR its derepression function was abolished. The amount of mRNA from the chromosomal cspA gene was much higher in cells overproducing the wild-type 5′ UTR by means of a plasmid than it was in cells overproducing the cold-box-deleted 5′ UTR. The stability of the chromosomal cspA mRNA in cells overproducing the wild-type 5′ UTR was almost identical to that in cells overproducing the cold-box-deleted 5′ UTR. Therefore, the derepression ofcspA caused by overproduction of 5′ UTR at the end of the acclimation phase occurs at the level of transcription but not by mRNA stabilization, indicating that the cold-box region plays a negative role in cspA transcription in cold shock-adapted cells. The role of the cold-box region was further confirmed with acspA mutant strain containing a cold-box-deletedcspA gene integrated into the chromosome, which showed a high level of constitutive production of CspA but not CspB during exponential growth at low temperature.

scholarly journals Extended −10 Motif Is Critical for Activity of the cspA Promoter but Does Not Contribute to Low-Temperature Transcription

2005 ◽  
Vol 187 (18) ◽  
pp. 6584-6589 ◽  
Author(s):  
Sangita Phadtare ◽  
Konstantin Severinov
Keyword(s):  
Low Temperature ◽  
Cold Shock ◽  
Cold Shock Protein ◽  
Mrna Stabilization ◽  
Cold Sensitive ◽  
Temperature Downshift ◽  
Cspa Promoter ◽  
High Level

ABSTRACT Bacterial promoters belonging to the extended −10 class contain a conserved TGn motif upstream of the −10 promoter consensus element. Open promoter complexes can be formed on some extended −10 Escherichia coli promoters at temperatures as low as 6°C, when complexes on most promoters are closed. The promoter of cspA, a gene that codes for the major cold shock protein CspA of E. coli, contains an extended −10 motif. CspA is dramatically induced upon temperature downshift from 37 to 15°C, and its cold shock induction has been attributed to transcription, translation, and mRNA stabilization effects. Here, we show that though the extended −10 motif is critical for high-level expression of cspA, it does not contribute to low-temperature expression. In fact, transcription from the wild-type cspA promoter is cold sensitive in vitro and in vivo. Thus, transcription appears to play little or no role in low-temperature induction of cspA expression.

scholarly journals Cold Shock Exoribonuclease R (VacB) Is Involved in Aeromonas hydrophila Pathogenesis

2008 ◽  
Vol 190 (10) ◽  
pp. 3467-3474 ◽  
Author(s):  
Tatiana E. Erova ◽  
Valeri G. Kosykh ◽  
Amin A. Fadl ◽  
Jian Sha ◽  
Amy J. Horneman ◽  
...  
Keyword(s):  
Low Temperature ◽  
Aeromonas Hydrophila ◽  
Cold Shock ◽  
Shigella Flexneri ◽  
Cold Shock Protein ◽  
Amino Acid Residues ◽  
Wild Type ◽  
Rnase R ◽  
Lethal Doses

ABSTRACT In this study, we cloned and sequenced a virulence-associated gene (vacB) from a clinical isolate SSU of Aeromonas hydrophila. We identified this gene based on our recently annotated genome sequence of the environmental isolate ATCC 7966T of A. hydrophila and the vacB gene of Shigella flexneri. The A. hydrophila VacB protein contained 798 amino acid residues, had a molecular mass of 90.5 kDa, and exhibited an exoribonuclease (RNase R) activity. The RNase R of A. hydrophila was a cold-shock protein and was required for bacterial growth at low temperature. The vacB isogenic mutant, which we developed by homologous recombination using marker exchange mutagenesis, was unable to grow at 4°C. In contrast, the wild-type (WT) A. hydrophila exhibited significant growth at this low temperature. Importantly, the vacB mutant was not defective in growth at 37°C. The vacB mutant also exhibited reduced motility, and these growth and motility phenotype defects were restored after complementation of the vacB mutant. The A. hydrophila RNase R-lacking strain was found to be less virulent in a mouse lethality model (70% survival) when given by the intraperitoneal route at as two 50% lethal doses (LD50). On the other hand, the WT and complemented strains of A. hydrophila caused 80 to 90% of the mice to succumb to infection at the same LD50 dose. Overall, this is the first report demonstrating the role of RNase R in modulating the expression of A. hydrophila virulence.

scholarly journals Two-Component-System Histidine Kinases Involved in Growth of Listeria monocytogenes EGD-e at Low Temperatures

2015 ◽  
Vol 81 (12) ◽  
pp. 3994-4004 ◽  
Author(s):  
Anna Pöntinen ◽  
Annukka Markkula ◽  
Miia Lindström ◽  
Hannu Korkeala
Keyword(s):  
Low Temperature ◽  
Histidine Kinase ◽  
Cold Shock ◽  
Wild Type ◽  
Histidine Kinases ◽  
Content Type ◽  
Expression Levels ◽  
Two Component ◽  
Cold Sensitive

ABSTRACTTwo-component systems (TCSs) aid bacteria in adapting to a wide variety of stress conditions. While the role of TCS response regulators in the cold tolerance of the psychrotrophic foodborne pathogenListeria monocytogeneshas been demonstrated previously, no comprehensive studies showing the role of TCS histidine kinases ofL. monocytogenesat low temperature have been performed. We compared the expression levels of each histidine kinase-encoding gene ofL. monocytogenesEGD-e in logarithmic growth phase at 3°C and 37°C, as well as the expression levels 30 min, 3 h, and 7 h after cold shock at 5°C and preceding cold shock (at 37°C). We constructed a deletion mutation in each TCS histidine kinase gene, monitored the growth of the EGD-e wild-type and mutant strains at 3°C and 37°C, and measured the minimum growth temperature of each strain. Two genes,yycGandlisK, proved significant in regard to induced relative expression levels under cold conditions and cold-sensitive mutant phenotypes. Moreover, the ΔresEmutant showed a lower growth rate than that of wild-type EGD-e at 3°C. Eleven other genes showed upregulated gene expression but revealed no cold-sensitive phenotypes. The results show that the histidine kinases encoded byyycGandlisKare important for the growth and adaptation ofL. monocytogenesEGD-e at low temperature.

scholarly journals α-Tocopherol Is Essential for Acquired Chill-Light Tolerance in the Cyanobacterium Synechocystis sp. Strain PCC 6803

2007 ◽  
Vol 190 (5) ◽  
pp. 1554-1560 ◽  
Author(s):  
Yang Yang ◽  
Chuntao Yin ◽  
Weizhi Li ◽  
Xudong Xu
Keyword(s):  
Escherichia Coli ◽  
Low Temperature ◽  
Light Stress ◽  
Wild Type ◽  
Regulated Expression ◽  
Synechocystis Sp ◽  
Pcc 6803

ABSTRACT Unlike Escherichia coli, the cyanobacterium Synechocystis sp. strain PCC 6803 is insensitive to chill (5°C) in the dark but rapidly losses viability when exposed to chill in the light (100 μmol photons m−2 s−1). Preconditioning at a low temperature (15°C) greatly enhances the chill-light tolerance of Synechocystis sp. strain PCC 6803. This phenomenon is called acquired chill-light tolerance (ACLT). Preconditioned wild-type cells maintained a substantially higher level of α-tocopherol after exposure to chill-light stress. Mutants unable to synthesize α-tocopherol, such as slr1736, slr1737, slr0089, and slr0090 mutants, almost completely lost ACLT. When exposed to chill without light, these mutants showed no or a slight difference from the wild type. When complemented, the slr0089 mutant regained its ACLT. Copper-regulated expression of slr0090 from P petE controlled the level of α-tocopherol and ACLT. We conclude that α-tocopherol is essential for ACLT of Synechocystis sp. strain PCC 6803. The role of α-tocopherol in ACLT may be based largely on a nonantioxidant activity that is not possessed by other tocopherols or pathway intermediates.

scholarly journals Mechanisms of Dinucleotide Repeat Instability in Escherichia coli

Genetics ◽  
2000 ◽  
Vol 154 (2) ◽  
pp. 533-542
Author(s):  
Marc Bichara ◽  
Isabelle Pinet ◽  
Sylvie Schumacher ◽  
Robert P P Fuchs
Keyword(s):  
Escherichia Coli ◽  
Mismatch Repair ◽  
Genetic Instability ◽  
Positional Cloning ◽  
Dinucleotide Repeats ◽  
Disease Pathogenesis ◽  
Complementary Sequence ◽  
Phylogenetic Studies ◽  
High Level

Abstract The high level of polymorphism of microsatellites has been used for a variety of purposes such as positional cloning of genes associated with diseases, forensic medicine, and phylogenetic studies. The discovery that microsatellites are associated with human diseases, not only as markers of risk but also directly in disease pathogenesis, has triggered a renewed interest in understanding the mechanism of their instability. In this work we have investigated the role of DNA replication, long patch mismatch repair, and transcription on the genetic instability of all possible combinations of dinucleotide repeats in Escherichia coli. We show that the (GpC) and (ApT) self-complementary sequence repeats are the most unstable and that the mode of replication plays an important role in their instability. We also found that long patch mismatch repair is involved in avoiding both short deletion and expansion events and also in instabilities resulting from the processing of bulges of 6 to 8 bp for the (GpT/ApC)- and (ApG/CpT)-containing repeats. For each dinucleotide sequence repeat, we propose models for instability that involve the possible participation of unusual secondary structures.

scholarly journals Molecular survey of mcr1 and mcr2 plasmid mediated colistin resistance genes in Escherichia coli isolates of animal origin in Iran

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Kayhan Ilbeigi ◽  
Mahdi Askari Badouei ◽  
Hossein Vaezi ◽  
Hassan Zaheri ◽  
Sina Aghasharif ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Resistance Genes ◽  
Companion Animals ◽  
Multidrug Resistant ◽  
Animal Origin ◽  
Colistin Resistance ◽  
E Coli ◽  
High Level ◽  
Farming Industry

Abstract Objectives The emergence of colistin-resistant Enterobacteriaceae from human and animal sources is one of the major public health concerns as colistin is the last-resort antibiotic for treating infections caused by multidrug-resistant Gram-negative bacteria. We aimed to determine the prevalence of the prototype widespread colistin resistance genes (mcr-1 and mcr-2) among commensal and pathogenic Escherichia coli strains isolated from food-producing and companion animals in Iran. Results A total of 607 E. coli isolates which were previously collected from different animal sources between 2008 and 2016 used to uncover the possible presence of plasmid-mediated colistin resistance genes (mcr-1 and mcr-2) by PCR. Overall, our results could not confirm the presence of any mcr-1 or mcr-2 positive E. coli among the studied isolates. It is concluded that despite the important role of food-producing animals in transferring the antibiotic resistance, they were not the main source for carriage of mcr-1 and mcr-2 in Iran until 2016. This study suggests that the other mcr variants (mcr-3 to mcr-9) might be responsible for conferring colistin resistance in animal isolates in Iran. The possible linkage between pig farming industry and high level of mcr carriage in some countries needs to be clarified in future prospective studies.

scholarly journals Contributions of individual mechanisms to fluoroquinolone resistance in 36 Escherichia coli strains isolated from humans and animals.

1996 ◽  
Vol 40 (10) ◽  
pp. 2380-2386 ◽  
Author(s):  
M J Everett ◽  
Y F Jin ◽  
V Ricci ◽  
L J Piddock
Keyword(s):  
Escherichia Coli ◽  
Dna Sequences ◽  
Quinolone Resistance ◽  
Fluoroquinolone Resistance ◽  
Polymorphism Analysis ◽  
Single Mutation ◽  
Wild Type ◽  
Single Strand Conformational Polymorphism ◽  
E Coli ◽  
High Level

Twenty-eight human isolates of Escherichia coli from Argentina and Spain and eight veterinary isolates received from the Ministry of Agriculture Fisheries and Foods in the United Kingdom required 2 to > 128 micrograms of ciprofloxacin per ml for inhibition. Fragments of gyrA and parC encompassing the quinolone resistance-determining region were amplified by PCR, and the DNA sequences of the fragments were determined. All isolates contained a mutation in gyrA of a serine at position 83 (Ser83) to an Leu, and 26 isolates also contained a mutation of Asp87 to one of four amino acids: Asn (n = 14), Tyr (n = 6), Gly (n = 5), or His (n = 1). Twenty-four isolates contained a single mutation in parC, either a Ser80 to Ile (n = 17) or Arg (n = 2) or a Glu84 to Lys (n = 3). The role of a mutation in gyrB was investigated by introducing wild-type gyrB (pBP548) into all isolates; for three transformants MICs of ciprofloxacin were reduced; however, sequencing of PCR-derived fragments containing the gyrB quinolone resistance-determining region revealed no changes. The analogous region of parE was analyzed in 34 of 36 isolates by single-strand conformational polymorphism analysis and sequencing; however, no amino acid substitutions were discovered. The outer membrane protein and lipopolysaccharide profiles of all isolates were compared with those of reference strains, and the concentration of ciprofloxacin accumulated (with or without 100 microM carbony cyanide m-chlorophenylhydrazone [CCCP] was determined. Twenty-two isolates accumulated significantly lower concentrations of ciprofloxacin than the wild-type E. coli isolate; nine isolates accumulated less then half the concentration. The addition of CCCP increased the concentration of ciprofloxacin accumulated, and in all but one isolate the percent increase was greater than that in the control strains. The data indicate that high-level fluoroquinolone resistance in E. coli involves the acquisition of mutations at multiple loci.

scholarly journals Cold Shock Proteins of Lactococcus lactis MG1363 Are Involved in Cryoprotection and in the Production of Cold-Induced Proteins

2001 ◽  
Vol 67 (11) ◽  
pp. 5171-5178 ◽  
Author(s):  
Jeroen A. Wouters ◽  
Hélène Frenkiel ◽  
Willem M. de Vos ◽  
Oscar P. Kuipers ◽  
Tjakko Abee
Keyword(s):  
Low Temperature ◽  
Lactococcus Lactis ◽  
Type Strain ◽  
Wild Type Strain ◽  
Cold Shock ◽  
Transcriptional Level ◽  
Wild Type ◽  
Cold Shock Proteins ◽  
Shock Proteins ◽  
Induced Proteins

ABSTRACT Members of the group of 7-kDa cold-shock proteins (CSPs) are the proteins with the highest level of induction upon cold shock in the lactic acid bacterium Lactococcus lactis MG1363. By using double-crossover recombination, two L. lactis strains were generated in which genes encoding CSPs are disrupted: L. lactis NZ9000ΔAB lacks the tandemly orientatedcspA and cspB genes, and NZ9000ΔABE lackscspA, cspB, and cspE. Both strains showed no differences in growth at normal and at low temperatures compared to that of the wild-type strain, L. lactis NZ9000. Two-dimensional gel electrophoresis showed that upon disruption of thecspAB genes, the production of remaining CspE at low temperature increased, and upon disruption of cspA, cspB, and cspE, the production of CspD at normal growth temperatures increased. Northern blot analysis showed that control is most likely at the transcriptional level. Furthermore, it was established by a proteomics approach that some (non-7-kDa) cold-induced proteins (CIPs) are not cold induced in the csp-lacking strains, among others the histon-like protein HslA and the signal transduction protein LlrC. This supports earlier observations (J. A. Wouters, M. Mailhes, F. M. Rombouts, W. M. De Vos, O. P. Kuipers, and T. Abee, Appl. Environ. Microbiol. 66:3756–3763, 2000). that the CSPs of L. lactis might be directly involved in the production of some CIPs upon low-temperature exposure. Remarkably, the adaptive response to freezing by prior exposure to 10°C was significantly reduced in strain NZ9000ΔABE but not in strain NZ9000ΔAB compared to results with wild-type strain NZ9000, indicating a notable involvement of CspE in cryoprotection.

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