scholarly journals Is the cellular and molecular machinery docile in the stationary phase of Escherichia coli?

2015 ◽  
Vol 43 (2) ◽  
pp. 168-171 ◽  
Author(s):  
Parul Mehta ◽  
Goran Jovanovic ◽  
Liming Ying ◽  
Martin Buck
Keyword(s):  
Stationary Phase ◽  
Single Molecule ◽  
Growth Phase ◽  
Bound States ◽  
Cell Envelope ◽  
Stationary Phases ◽  
Negative Regulator ◽  
Logarithmic Phase ◽  
Bacterial Cells ◽  
Highly Active

The bacterial cell envelope retains a highly dense cytoplasm. The properties of the cytoplasm change with the metabolic state of the cell, the logarithmic phase (log) being highly active and the stationary phase metabolically much slower. Under the differing growth phases, many different types of stress mechanisms are activated in order to maintain cellular integrity. One such response in enterobacteria is the phage shock protein (Psp) response that enables adaptation to the inner membrane (IM) stress. The Psp system consists of a transcriptional activator PspF, negative regulator PspA, signal sensors PspBC, with PspA and PspG acting as effectors. The single molecule imaging of the PspF showed the existence of dynamic communication between the nucleoid-bound states of PspF and membrane via negative regulator PspA and PspBC sensors. The movement of proteins in the cytoplasm of bacterial cells is often by passive diffusion. It is plausible that the dynamics of the biomolecules differs with the state of the cytoplasm depending on the growth phase. Therefore, the Psp response proteins might encounter the densely packed glass-like properties of the cytoplasm in the stationary phase, which can influence their cellular dynamics and function. By comparing the properties of the log and stationary phases, we find that the dynamics of PspF are influenced by the growth phase and may be controlled by the changes in the cytoplasmic fluidity.

scholarly journals Variation of Physiochemical Properties and Cell Association Activity of Membrane Vesicles with Growth Phase in Pseudomonas aeruginosa

2010 ◽  
Vol 76 (11) ◽  
pp. 3732-3739 ◽  
Author(s):  
Yosuke Tashiro ◽  
Sosaku Ichikawa ◽  
Motoyuki Shimizu ◽  
Masanori Toyofuku ◽  
Naoki Takaya ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Stationary Phase ◽  
Stationary Phases ◽  
Membrane Vesicles ◽  
Exponential Phase ◽  
Phase Changes ◽  
Bacterial Cells ◽  
Physiochemical Properties ◽  
Cell Association ◽  
Phase Surface

ABSTRACT Pseudomonas aeruginosa and other Gram-negative bacteria release membrane vesicles (MVs) from their surfaces, and MVs have an ability to interact with bacterial cells. Although it has been known that many bacteria have mechanisms that control their phenotypes with the transition from exponential phase to stationary phase, changes of properties in released MVs have been poorly understood. Here, we demonstrate that MVs released by P. aeruginosa during the exponential and stationary phases possess different physiochemical properties. MVs purified from the stationary phase had higher buoyant densities than did those purified from the exponential phase. Surface charge, characterized by zeta potential, of MVs tended to be more negative as the growth shifted to the stationary phase, although the charges of PAO1 cells were not altered. Pseudomonas quinolone signal (PQS), one of the regulators related to MV production in P. aeruginosa, was lower in MVs purified from the exponential phase than in those from the stationary phase. MVs from the stationary phase more strongly associated with P. aeruginosa cells than did those from the exponential phase. Our findings suggest that properties of MVs are altered to readily interact with bacterial cells along with the growth transition in P. aeruginosa.

scholarly journals Plasmid transfer in planktonically-grown cultures and biofilms

2021 ◽  
Author(s):  
Farhana Shamsad
Keyword(s):  
Cell Growth ◽  
Stationary Phase ◽  
Growth Phase ◽  
Nutrient Concentrations ◽  
Bacterial Cells ◽  
Growth Phases ◽  
Rt Pcr ◽  
Lower Growth ◽  
Donor Cells ◽  
Significant Difference

Conjugation of plasmids is widespread among bacteria and contributes to the spread of antibiotic resistance. In the natural environment, microorganisms predominantly exist in the form of biofilms or other bioaggregates, where they may be exposed to contaminants such as antibiotics, at subinhibitory concentrations. Bacterial cells in older biofilms have lower growth activity due to oxygen and nutrient limitation in the deeper layers of the biofilms. In batch culture, population growth eventually ceases during the stationary phase. Thus, the steady state of biofilms may resemble stationary growth phase cultures. Our objectives were to study (i) the effect of cell growth phases and (ii) subinhibitory and minimum inhibitory concentrations (MIC) of antibiotics on transconjugant formation in both batch cultures and biofilms. Additionally, (iii) the effect of variable nutrient concentrations on MIC was investigated and (iv) an optimization of RT-PCR method for the detection of traA gene (which encodes pilus biosynthesis) expression was carried out. To study the effect of cell growth phases on transconjugant formation, plate matings were carried out utilizing planktonic cultures grown to exponential or stationary phase of donor and recipient strains. The results showed that transconjugant abundance was the highest (20± 0.08%) when both plasmid donor and recipient cells were grown to the stationary phase. However, the growth phase of the donor did not seem to play a role in biofilms. When donor cells were harvested from either the exponential or stationary phase of growth, and inoculated into 24 h old recipient biofilms, there was no statistically significant difference between transconjugant abundance. A higher percentage of transconjugants was detected in plate matings when the donor was exposed to 0.5× minimum inhibitory concentration of gentamicin and additionally challenged with gentamicin at MIC. In biofilms, transconjugant formation was not enhanced when the donor cells were grown with 0.5× MIC gentamicin, and 0.5× MIC gentamicin was added to the biofilms. A decrease in nutrient concentration was associated with a decrease in the MIC. traA expression, detected using RT-PCR in plasmid donor cells grown to early exponential and late exponential phases did not coincide with an increase in transconjugants.

scholarly journals Combination of flucloxacillin and gentamicin inhibits toxic shock syndrome toxin 1 production by Staphylococcus aureus in both logarithmic and stationary phases of growth.

1997 ◽  
Vol 41 (8) ◽  
pp. 1682-1685 ◽  
Author(s):  
P van Langevelde ◽  
J T van Dissel ◽  
C J Meurs ◽  
J Renz ◽  
P H Groeneveld
Keyword(s):  
Staphylococcus Aureus ◽  
Stationary Phase ◽  
Bacterial Growth ◽  
Toxic Shock Syndrome ◽  
Stationary Phases ◽  
Logarithmic Phase ◽  
Toxic Shock ◽  
Viable Bacteria ◽  
Static Effect ◽  
Toxic Shock Syndrome Toxin

Production of exotoxins by staphylococci and streptococci may lead to the development of toxic shock syndrome (TSS). Because clindamycin inhibits exotoxin production, its use has been advocated for the treatment of TSS. However, the bacteriostatic action of clindamycin might be a disadvantage for the treatment of overwhelming infections. We investigated the effects of flucloxacillin and gentamicin on exotoxin production, because incubation with these antibiotics combines bactericidal action with protein synthesis inhibition. Staphylococcus aureus during the logarithmic and stationary phases of growth was incubated with either clindamycin, flucloxacillin, or a combination of flucloxacillin and gentamicin at concentrations of 2 or 10 times the MIC. In logarithmic-phase cultures clindamycin had a static effect on bacterial growth. After incubation with flucloxacillin, either alone or in combination with gentamicin, a rapid and large reduction in the number of viable bacteria was demonstrated. In stationary-phase cultures none of the antibiotics significantly changed the number of viable bacteria. TSS toxin 1 (TSST-1) production during logarithmic-phase growth was inhibited by > or =95% by all antibiotics. In stationary-phase cultures, clindamycin, flucloxacillin, and the combination of flucloxacillin and gentamicin inhibited TSST-1 production by 95, 30, and 75%, respectively, compared with the level of exotoxin production in the controls. The present results indicate that clindamycin inhibits TSST-1 production and exerts bacteriostatic activity in both bacterial growth phases. Because the combination of flucloxacillin and gentamicin combines the inhibition of exotoxin production with high bactericidal activity at least in logarithmic-phase cultures, it should be considered an alternative to clindamycin for the treatment of exotoxin-mediated diseases, especially in patients with overwhelming infections.

scholarly journals Expression Profiles and Physiological Roles of Two Types of Molecular Chaperonins from the Hyperthermophilic Archaeon Thermococcus kodakarensis

2008 ◽  
Vol 74 (23) ◽  
pp. 7306-7312 ◽  
Author(s):  
Shinsuke Fujiwara ◽  
Ryohei Aki ◽  
Masaya Yoshida ◽  
Hiroki Higashibata ◽  
Tadayuki Imanaka ◽  
...  
Keyword(s):  
Cell Growth ◽  
Stationary Phase ◽  
Stationary Phases ◽  
Expression Profiles ◽  
Mrna Level ◽  
Temperature Adaptation ◽  
Logarithmic Phase ◽  
Temperature Dependent ◽  
Independent Manner ◽  
Thermococcus Kodakarensis

ABSTRACT Thermococcus kodakarensis possesses two chaperonins, CpkA and CpkB, and their expression is induced by the downshift and upshift, respectively, of the cell cultivation temperature. The expression levels of the chaperonins were examined by using specific antibodies at various cell growth temperatures in the logarithmic and stationary phases. At 60°C, CpkA was highly expressed in both the logarithmic and stationary phases; however, CpkB was not expressed in either phase. At 85°C, CpkA and CpkB were expressed in both phases; however, the CpkA level was decreased in the stationary phase. At 93°C, CpkA was expressed only in the logarithmic phase and not in the stationary phase. In contrast, CpkB was highly expressed in both phases. The results of reverse transcription-PCR experiments showed the same growth phase- and temperature-dependent profiles as observed in immunoblot analyses, indicating that the expression of cpkA and cpkB is regulated at the mRNA level. The cpkA or cpkB gene disruptant was then constructed, and its growth profile was monitored. The cpkA disruptant showed poor cell growth at 60°C but no significant defects at 85°C and 93°C. On the other hand, cpkB disruption led to growth defects at 93°C but no significant defects at 60°C and 85°C. These data indicate that CpkA and CpkB are necessary for cell growth at lower and higher temperatures, respectively. The logarithmic-phase-dependent expression of CpkA at 93°C suggested that CpkA participates in initial cell growth in addition to lower-temperature adaptation. Promoter mapping and quantitative analyses using the Phr (Pyrococcus heat-shock regulator) gene disruptant revealed that temperature-dependent expression was achieved in a Phr-independent manner.

scholarly journals Analisis Kemampuan Akumulasi Polyfosfat pada Tiap Fase Pertumbuhan Isolat Bakteri Toleran Uranium

2020 ◽  
Vol 9 (1) ◽  
pp. 81
Author(s):  
Heni Mutmainnah ◽  
Muhammad Rijal
Keyword(s):  
Stationary Phase ◽  
Inorganic Phosphate ◽  
High Energy ◽  
Lag Phase ◽  
Logarithmic Phase ◽  
Bacterial Cells ◽  
Test Results ◽  
Redox Transformation ◽  
Phase Measurements ◽  
Made In

Polyphosphate is a straight chain biopolymer consisting of tens to hundreds of phosphate residues that are linked by high energy phosphoanhydride bonds, polyphosphate plays an important role in the bioremediation process of uranium waste, especially in the process of uranium metal precipitation in bacterial cells. Some bacteria are known to have the potential to interact with uranium through redox transformation and bioprecipitation by releasing inorganic phosphate to bind uranium in the environment. Inorganic phosphate results from degradation of polyphosphates that accumulate in cells. This study aims to determine the ability of uranium-tolerant bacteria to accumulate polyphosphates during their growth phase. Measurements were made in 5 growth phases, namely the lag phase, the logarithmic phase, the beginning of the stationary phase, the stationary phase, and the stationary end. Quantitative analysis of polyphosphate accumulations was carried out using the Olsen & Dean method. The test results are known that the uranium-tolerant bacterial isolat is able to accumulate the most optimal polyphosphate in the stationary phase, especially at the 48th hour and the lowest polyP accumulation is found in the initial stationary phase at the 24th hour.

scholarly journals Taxon- and Growth Phase-Specific Antioxidant Production by Chlorophyte, Bacillariophyte, and Haptophyte Strains Isolated From Tropical Waters

2020 ◽  
Vol 8 ◽  
Author(s):  
Norazira Abdu Rahman ◽  
Tomoyo Katayama ◽  
Mohd Effendy Abd Wahid ◽  
Nor Azman Kasan ◽  
Helena Khatoon ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Stationary Phase ◽  
Antioxidant Capacity ◽  
Growth Phase ◽  
Stationary Phases ◽  
Exponential Phase ◽  
Antioxidant Compounds ◽  
Antioxidant Compound ◽  
Scavenging Capacity ◽  
Β Carotene

Antioxidants found in microalgae play an essential role in both animals and humans, against various diseases and aging processes by protecting cells from oxidative damage. In this study, 26 indigenous tropical marine microalgae were screened. Out of the 26 screened strains, 10 were selected and were further investigated for their natural antioxidant compounds which include carotenoids, phenolics, and fatty acids collected in their exponential and stationary phases. The antioxidant capacity was also evaluated by a total of four assays, which include ABTS, DPPH, superoxide radical (O2•–) scavenging capacity, and nitric oxide (•NO–) scavenging capacity. This study revealed that the antioxidant capacity of the microalgae varied between divisions, strains, and growth phase and was also related to the content of antioxidant compounds present in the cells. Carotenoids and phenolics were found to be the major contributors to the antioxidant capacity, followed by polyunsaturated fatty acids linoleic acid (LA), eicosapentaenoic acid (EPA), arachidonic acid (ARA), and docosahexaenoic acid (DHA) compared to other fatty acids. The antioxidant capacity of the selected bacillariophytes and haptophytes was found to be positively correlated to phenolic (R2-value = 0.623, 0.714, and 0.786 with ABTS, DPPH, and •NO–) under exponential phase, and to carotenoid fucoxanthin and β-carotene (R2 value = 0.530, 0.581 with ABTS, and 0.710, 0.795 with O2•–) under stationary phase. Meanwhile, antioxidant capacity of chlorophyte strains was positively correlated with lutein, β-carotene and zeaxanthin under the exponential phase (R2 value = 0.615, 0.615, 0.507 with ABTS, and R2 value = 0.794, 0.659, and 0.509 with •NO–). In the stationary phase, chlorophyte strains were positively correlated with violaxanthin (0.755 with •NO–), neoxanthin (0.623 with DPPH, 0.610 with •NO–), and lutein (0.582 with •NO–). This study showed that antioxidant capacity and related antioxidant compound production of tropical microalgae strains are growth phase-dependent. The results can be used to improve the microalgal antioxidant compound production for application in pharmaceutical, nutraceutical, food, and feed industry.

scholarly journals Efflux Impacts Intracellular Accumulation Only in Actively Growing Bacterial Cells

mBio ◽  
2021 ◽  
Author(s):  
Emily E. Whittle ◽  
Helen E. McNeil ◽  
Eleftheria Trampari ◽  
Mark Webber ◽  
Tim W. Overton ◽  
...  
Keyword(s):  
Stationary Phase ◽  
Drug Targets ◽  
Bacterial Infections ◽  
Cell Envelope ◽  
Bacterial Cells ◽  
Intracellular Accumulation ◽  
Predominant Factor ◽  
Novel Drug ◽  
Intracellular Targets ◽  
Slow Growing

This study shows that efflux is important for maintaining low intracellular accumulation only in actively growing cells and that envelope permeability is the predominant factor in stationary-phase cells. This conclusion means that (i) antibiotics with intracellular targets may be less effective in complex infections with nongrowing or slow-growing bacteria, where intracellular accumulation may be low; (ii) efflux inhibitors may be successful in potentiating the activity of existing antibiotics, but potentially only for bacterial infections where cells are actively growing; and (iii) the remodeling of the cell envelope prior to stationary phase could provide novel drug targets.

scholarly journals Ribosomal Protein S1 Specifically Binds to the 5′ Untranslated Region of the Pseudomonas aeruginosa Stationary-Phase Sigma Factor rpoS mRNA in the Logarithmic Phase of Growth

2004 ◽  
Vol 186 (15) ◽  
pp. 4903-4909 ◽  
Author(s):  
Milica Ševo ◽  
Emanuele Buratti ◽  
Vittorio Venturi
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Stationary Phase ◽  
Ribosomal Protein ◽  
Sigma Factor ◽  
Untranslated Region ◽  
Stationary Phases ◽  
Translation Regulation ◽  
Logarithmic Phase ◽  
Ribosomal Protein S1 ◽  
Sigma Factor Rpos

ABSTRACT The rpoS gene encodes the stationary-phase sigma factor (RpoS or σs), which was identified in several gram-negative bacteria as a central regulator controlling the expression of genes involved in cell survival in response to cessation of growth (stationary phase) and providing cross-protection against various stresses. In Pseudomonas aeruginosa, the levels of σs increase dramatically at the onset of the stationary phase and are regulated at the transcriptional and posttranscriptional levels. The P. aeruginosa rpoS gene is transcribed as a monocistronic rpoS mRNA transcript comprised of an unusually long 373-bp 5′ untranslated region (5′ UTR). In this study, the 5′ UTR and total protein extracts from P. aeruginosa logarithmic and stationary phases of growth were used in order to investigate the protein-RNA interactions that may modulate the translational process. It was observed that a 69-kDa protein, which corresponded to ribosomal protein S1, preferentially binds the 5′ UTR of the rpoS mRNA in the logarithmic phase and not in the stationary phase. This is the first report of a protein-rpoS mRNA 5′ UTR interaction in P. aeruginosa, and the possible involvement of protein S1 in translation regulation of rpoS is discussed.

Behavior of mitochondria during sporulation in yeast

1978 ◽  
Vol 36 (2) ◽  
pp. 406-407
Author(s):  
Barbara J. Stevens
Keyword(s):  
Cell Wall ◽  
Stationary Phase ◽  
Growth Phase ◽  
Serial Section ◽  
Logarithmic Phase ◽  
Serial Sections ◽  
Vegetative Cells ◽  
Thin Sections ◽  
Section Technique ◽  
Single Mitochondrion

The number and the form of mitochondria in vegetatively growing yeast, Saccharo-myces cerevisiae, have previously been determined by the use of serial thin sections of entire cells. It was found that the number of mitochondria is directly related to the growth phase: logarithmic phase cells contain few mitochondria, less than 10, while stationary phase cells have numerous organelles, from 30 to 50 individual mitochondria. A single mitochondrion was found in 2 log phase, glucose-repressed cells, but all other cells had more than one mitochondrion. In the present study, the behavior of the chondriome during meiosis and sporulation in yeast was followed by the serial section technique and was compared to that in vegetative cells.Diploid strains Z193, Z239-6B6B and s4l were obtained from R. and M. Esposito and S. Klapholz (Univ. of Chicago) and serial sections of strain 112 were kindly provided by D. Zickler (Univ. Paris-Sud). Cells were fixed in glutaraldehyde, treated with glusulase (Endo Lab.) or zymolyase (Kirin Brew. Co.) to remove the cell wall, and post-fixed in Dalton's chrome osmium.

scholarly journals DNA-Binding Proteins Possibly Involved in Regulation of the Post-Logarithmic-Phase Expression of Lipoprotein P35 in Borrelia burgdorferi

2000 ◽  
Vol 182 (2) ◽  
pp. 522-525 ◽  
Author(s):  
Karl J. Indest ◽  
Mario T. Philipp
Keyword(s):  
Dna Binding ◽  
Borrelia Burgdorferi ◽  
Stationary Phase ◽  
Growth Phase ◽  
Promoter Region ◽  
Protein Complexes ◽  
Phase Cell ◽  
Logarithmic Phase ◽  
Specific Complex

ABSTRACT Previously, we have shown that the transcription ofp35, a lipoprotein gene of Borrelia burgdorferi, is upregulated or initiated during the post-logarithmic bacterial growth phase in vitro. To identify potential regulatory factors, we examined the formation of DNA-protein complexes by electromobility shift assay, using a 157-bp DNA fragment that spans the p35 promoter region and cell-free extracts of spirochetes harvested from both logarithmic and stationary growth phases. The binding properties of the extracts with the promoter region of the flaB gene, a constitutively expressed, growth-phase-independent gene, were also compared. The results from these experiments demonstrate that B. burgdorferistationary-phase cell-free extracts have a growth-phase-dependent DNA binding protein that interacts specifically with the p35promoter region. We show, in addition, that a segment from the 157-bpp35 promoter region which contains both a T-rich stretch and an inverted repeat is able to compete off the stationary-phase-specific complex when the segment is present in molar excess.

Sign in / Sign up

Export Citation Format

Share Document