scholarly journals Expression of Invasin and Motility Are Coordinately Regulated in Yersinia enterocolitica

1998 ◽  
Vol 180 (4) ◽  
pp. 793-800 ◽  
Author(s):  
Julie L. Badger ◽  
Virginia L. Miller
Keyword(s):  
Stationary Phase ◽  
Yersinia Enterocolitica ◽  
Growth Phase ◽  
Temperature Regulation ◽  
Molecular Basis ◽  
Early Stationary Phase ◽  
Regulatory Mutants ◽  
E Coli ◽  
Regulatory Mutant

ABSTRACT The Yersinia enterocolitica inv gene encodes the primary invasion factor invasin, which has been previously shown to be critical in the initial stages of infection. The expression ofinv is influenced by growth phase and temperature and is maximal during late exponential-early stationary phase at 23°C. In addition, motility of Y. enterocolitica is regulated by temperature. Y. enterocolitica cells are motile when grown at lower temperatures (30°C or below), while bacteria grown at 37°C are nonmotile. This study was initiated to determine the molecular basis for the temperature regulation of inv expression. Two mutants were isolated that both showed a significant decrease in invasin expression but are hypermotile when grown at 23°C. The first mutant (JB1A8v) was a result of a random mTn5Km insertion into the uvrC gene. The uvrC mutant JB1A8v demonstrated a significant decrease in inv and an increase in fleB (encodes flagellin) expression. These results suggest that expression of inv and flagellin genes is coordinated at the level of transcription. The second regulatory mutant, JB16v, was a result of a targeted insertion into a locus similar to sspA which in E. coli encodes a stationary-phase regulator. The E. coli sspA gene was cloned and assayed for complementation in both of the regulatory mutants. It was determined that E. coli sspA restored invasin expression in both the uvrC mutant and thesspA mutant. In addition, the complementing clone decreased flagellin levels in these mutants.

scholarly journals Global Role for ClpP-Containing Proteases in Stationary-Phase Adaptation of Escherichia coli

2003 ◽  
Vol 185 (1) ◽  
pp. 115-125 ◽  
Author(s):  
Dieter Weichart ◽  
Nadine Querfurth ◽  
Mathias Dreger ◽  
Regine Hengge-Aronis
Keyword(s):  
Escherichia Coli ◽  
Stationary Phase ◽  
Growth Phase ◽  
Proteome Analysis ◽  
Resting Cells ◽  
Wild Type ◽  
Late Stationary Phase ◽  
E Coli ◽  
In The Wild ◽  
Dps Protein

ABSTRACT To elucidate the involvement of proteolysis in the regulation of stationary-phase adaptation, the clpA, clpX, and clpP protease mutants of Escherichia coli were subjected to proteome analysis during growth and during carbon starvation. For most of the growth-phase-regulated proteins detected on our gels, the clpA, clpX, or clpP mutant failed to mount the growth-phase regulation found in the wild type. For example, in the clpP and clpA mutant cultures, the Dps protein, the WrbA protein, and the periplasmic lysine-arginine-ornithine binding protein ArgT did not display the induction typical for late-stationary-phase wild-type cells. On the other hand, in the protease mutants, a number of proteins accumulated to a higher degree than in the wild type, especially in late stationary phase. The proteins affected in this manner include the LeuA, TrxB, GdhA, GlnA, and MetK proteins and alkyl hydroperoxide reductase (AhpC). These proteins may be directly degraded by ClpAP or ClpXP, respectively, or their expression could be modulated by a protease-dependent mechanism. From our data we conclude that the levels of most major growth-phase-regulated proteins in E. coli are at some point controlled by the activity of at least one of the ClpP, ClpA, and ClpX proteins. Cultures of the strains lacking functional ClpP or ClpX also displayed a more rapid loss of viability during extended stationary phase than the wild type. Therefore, regulation by proteolysis seems to be more important, especially in resting cells, than previously suspected.

scholarly journals Growth-Phase-Dependent Expression of the Cyclopeptide Antibiotic Microcin J25

2001 ◽  
Vol 183 (5) ◽  
pp. 1755-1764 ◽  
Author(s):  
Marı́a J. Chiuchiolo ◽  
Mónica A. Delgado ◽  
Ricardo N. Farı́as ◽  
Raúl A. Salomón
Keyword(s):  
Stationary Phase ◽  
Growth Phase ◽  
High Cell Density ◽  
Integration Host Factor ◽  
Early Stationary Phase ◽  
Stationary Phase Culture ◽  
Global Regulators ◽  
Phase Culture ◽  
Microcin J25 ◽  
Growth Induction

ABSTRACT Microcin J25 is a 2,107-Da, plasmid-encoded, cyclopeptide antibiotic produced by Escherichia coli. We have isolatedlacZ fusions to mcjA (encoding the 58-amino-acid microcin precursor) and mcjB andmcjC (which are required for microcin maturation), and the regulation of these fusions was used to identify factors that control the expression of these genes. The mcjA gene was found to be dramatically induced as cells entered the stationary phase. Expression of mcjA could be induced by resuspending uninduced exponential-phase cells in spent supernatant obtained from an early-stationary-phase culture. Induction of mcjAexpression was not dependent on high cell density, pH changes, anaerobiosis, or the buildup of some inducer. A starvation for carbon and inorganic phosphate induced mcjA expression, while under nitrogen limitation there was no induction at all. These results taken together suggest that stationary-phase induction ofmcjA is triggered by nutrient depletion. ThemcjB and mcjC genes were also regulated by the growth phase of the culture, but in contrast to mcjA, they showed substantial expression already during exponential growth. Induction of the microcin genes was demonstrated to be independent of RpoS, the cyclic AMP-Crp complex, OmpR, and H-NS. Instead, we found that the growth-phase-dependent expression of mcjA,mcjB, and mcjC may be explained by the concerted action of the positively acting transition state regulators ppGpp, Lrp, and integration host factor. Measurements of microcin J25 production by strains defective in these global regulators showed a good correlation with the reduced expression of the fusions in such mutant backgrounds.

scholarly journals Growth Phase-Coupled Alterations in Cell Structure and Function of Escherichia coli

2003 ◽  
Vol 185 (4) ◽  
pp. 1338-1345 ◽  
Author(s):  
Hideki Makinoshima ◽  
Shin-Ichi Aizawa ◽  
Hideo Hayashi ◽  
Takeyoshi Miki ◽  
Akiko Nishimura ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Stationary Phase ◽  
Cell Density ◽  
Growth Phase ◽  
Cell Structure ◽  
Volume Ratio ◽  
Density Increase ◽  
Electron Microscopic ◽  
Thin Sections ◽  
E Coli

ABSTRACT Escherichia coli cultures can be fractionated into more than 20 cell populations, each having a different bouyant density and apparently representing a specific stage of cell differentiation from exponential growth to stationary phase (H. Makinoshima, A. Nishimura, and A. Ishihama, Mol. Microbiol. 43:269-279, 2002). The density increase was found to be impaired at an early step for a mutant E. coli with the disrupted rpoS gene, which encodes the RNA polymerase RpoS (sigma-S) for stationary-phase gene transcription. This finding suggests that RpoS is need for the entire process of cell density increase. In the absence of RpoF sigma factor, the flagella are not formed as observed by electron microscopy, but the growth phase-coupled density increase takes place as in wild-type E. coli, confirming that the alteration in cell density is not directly correlated with the presence or absence of flagella. In the stationary-phase cells, accumulation of electron-dense areas was observed by electron microscopic observation of bacterial thin sections. By chemical determination, the increase in glycogen (or polysaccharides) was suggested to be one component, which contributes to the increase in weight-to-volume ratio of stationary-phase E. coli cells.

Effects of Norfloxacin and Rifampicin on Growth and Streptolysin S Production in Hemolytic Streptococci

1985 ◽  
Vol 40 (9-10) ◽  
pp. 647-651
Author(s):  
Akira Taketo ◽  
Yoriko Taketo
Keyword(s):  
Stationary Phase ◽  
Growth Phase ◽  
Cell Mass ◽  
Toxin Production ◽  
Early Stationary Phase ◽  
Streptolysin S ◽  
Enhanced Production ◽  
Acid Analogue ◽  
Phase Medium ◽  
Cellular Capacity

Abstract Norfloxacin, a nalidixic acid analogue, inhibited streptolysin S (SLS) production when added to young streptococcal culture. DNA synthesis was mainly affected, but increment of cell mass. RNA and protein was also significantly reduced in streptococci treated with norfloxacin. In stationary phase cells and in the washed resting bacteria, the toxin production was resistant to the drug. Pretreatment with norfloxacin did not abolish the cellular capacity to produce SLS. Although extracellular SLS was detectable at log phase of streptococcal growth, enhanced production of the toxin occurred upon cessation of coccal multiplication. In contrast to norfloxacin, lower concentration of rifampicin inhibited SLS production, even added at late log or early stationary phase. Roles of growth phase, medium and carrier in induction of SLS production were analyzed as well.

scholarly journals Reciprocal Transcriptional and Posttranscriptional Growth-Phase-Dependent Expression of sfh, a Gene That Encodes a Paralogue of the Nucleoid-Associated Protein H-NS

2006 ◽  
Vol 188 (21) ◽  
pp. 7581-7591 ◽  
Author(s):  
Marie Doyle ◽  
Charles J. Dorman
Keyword(s):  
Stationary Phase ◽  
Growth Phase ◽  
Exponential Growth ◽  
Shigella Flexneri ◽  
Mrna Translation ◽  
Amino Acid Sequence Homology ◽  
Early Stationary Phase ◽  
Transmissible Plasmid ◽  
Mrna And Protein Expression ◽  
High Level

ABSTRACT The IncHI1 self-transmissible plasmid pSf-R27 from Shigella flexneri 2a strain 2457T harbors sfh, a gene that codes for a protein with strong amino acid sequence homology to the global transcription regulator and nucleoid-associated protein H-NS and to its paralogue, StpA. Previously, we discovered that the expression of sfh mRNA is growth phase dependent such that in cultures growing in Lennox broth at 37°C, the transcript is readily detectable in the early stages of exponential growth but is not detectable at the onset of stationary phase. In contrast, the Sfh protein is poorly expressed in early-exponential growth when sfh mRNA is abundant whereas it is expressed to a high level in early stationary phase, when sfh transcript expression is low (P. Deighan, C. Beloin, and C. J. Dorman, Mol. Microbiol. 48:1401-1416, 2003). This unusual pattern of reciprocal mRNA and protein expression is not due to growth phase-dependent effects on either mRNA or protein stability, nor is it due to the known abilities of the Sfh, StpA, and H-NS proteins to influence sfh gene expression. Instead, our data point to a blockade of sfh mRNA translation in early-exponential growth that is relieved as the culture enters the stationary phase of growth. Replacing the 5′ end and translation initiation signals of the sfh mRNA with heterologous sequences did not alter the growth phase-dependent expression of the Sfh protein, suggesting that growth phase control of translation is intrinsic to another component of the message.

Morphological Characterization of Mycobacteriophage R1

1974 ◽  
Vol 32 ◽  
pp. 254-255
Author(s):  
B. L. Soloff ◽  
T. A. Rado
Keyword(s):  
Carbon Source ◽  
Stationary Phase ◽  
Growth Phase ◽  
Minimal Medium ◽  
Morphological Characterization ◽  
Logarithmic Growth Phase ◽  
Complete Lysis ◽  
Lysogenic Culture ◽  
Logarithmic Growth

Mycobacteriophage R1 was originally isolated from a lysogenic culture of M. butyricum. The virus was propagated on a leucine-requiring derivative of M. smegmatis, 607 leu−, isolated by nitrosoguanidine mutagenesis of typestrain ATCC 607. Growth was accomplished in a minimal medium containing glycerol and glucose as carbon source and enriched by the addition of 80 μg/ ml L-leucine. Bacteria in early logarithmic growth phase were infected with virus at a multiplicity of 5, and incubated with aeration for 8 hours. The partially lysed suspension was diluted 1:10 in growth medium and incubated for a further 8 hours. This permitted stationary phase cells to re-enter logarithmic growth and resulted in complete lysis of the culture.

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