Accumulation of intracellular carbon reserves in relation to chloramphenicol biosynthesis by Streptomyces venezuelae

1993 ◽  
Vol 39 (4) ◽  
pp. 377-383 ◽  
Author(s):  
Neelima Ranade ◽  
Leo C. Vining
Keyword(s):  
Stationary Phase ◽  
Exponential Growth ◽  
Culture Conditions ◽  
Nitrogen Depletion ◽  
Streptomyces Venezuelae ◽  
Storage Compounds ◽  
Trehalose Lipid

Two chloramphenicol-producing strains of Streptomyces venezuelae accumulated small amounts of polyhydroxybutyrate during exponential growth; the compound disappeared from the mycelium as the cultures entered stationary phase. Depletion of polyhydroxybutyrate coincided with chloramphenicol production but the amount of polymer stored in the mycelium was insufficient to supply the precursor requirement for biosynthesis of the antibiotic. Accumulation of polyhydroxybutyrate in the S. venezuelae strains was appreciably lower than in two other streptomycetes examined. Glycogen and lipids accumulated in the mycelium of S. venezuelae 13s during the stationary phase, after nitrogen depletion; under the culture conditions used, they were the principal storage compounds in S. venezuelae. Trehalose was absent from the mycelium in vegetative cultures grown under nonsporulating conditions but it was abundant in spores obtained from submerged and surface cultures. Glycogen and polyhydroxybutyrate were absent from spores.Key words: storage compounds, biosynthesis, polyhydroxybutyrate, glycogen, trehalose, lipid.

scholarly journals Adaptive reversion of a frameshift mutation in Escherichia coli.

Genetics ◽  
1991 ◽  
Vol 128 (4) ◽  
pp. 695-701 ◽  
Author(s):  
J Cairns ◽  
P L Foster
Keyword(s):  
Escherichia Coli ◽  
Stationary Phase ◽  
Exponential Growth ◽  
Frameshift Mutation ◽  
Rare Event ◽  
Lacz Fusion ◽  
Mutation Rates ◽  
Classical Studies ◽  
Selective Forces

Abstract Mutation rates are generally thought not to be influenced by selective forces. This doctrine rests on the results of certain classical studies of the mutations that make bacteria resistant to phages and antibiotics. We have studied a strain of Escherichia coli which constitutively expresses a lacI-lacZ fusion containing a frameshift mutation that renders it Lac-. Reversion to Lac+ is a rare event during exponential growth but occurs in stationary cultures when lactose is the only source of energy. No revertants accumulate in the absence of lactose, or in the presence of lactose if there is another, unfulfilled requirement for growth. The mechanism for such mutation in stationary phase is not known, but it requires some function of RecA which is apparently not required for mutation during exponential growth.

scholarly journals Acinetobacter baylyi Starvation-Induced Genes Identified through Incubation in Long-Term Stationary Phase

2010 ◽  
Vol 76 (14) ◽  
pp. 4905-4908 ◽  
Author(s):  
C. Phoebe Lostroh ◽  
Bruce A. Voyles
Keyword(s):  
Gene Expression ◽  
Stationary Phase ◽  
Batch Culture ◽  
Exponential Growth ◽  
Hypothetical Proteins ◽  
Acinetobacter Baylyi ◽  
Metabolic Gene Expression ◽  
Induced Genes ◽  
Dna Maintenance

ABSTRACT Acinetobacter species encounter cycles of feast and famine in nature. We show that populations of A cinetobacter baylyi strain ADP1 remain dynamic for 6 weeks in batch culture. We created a library of lacZ reporters inserted into SalI sites in the genome and then isolated 30 genes with lacZ insertions whose expression was induced by starvation during long-term stationary phase compared with their expression during exponential growth. The genes encode metabolic, gene expression, DNA maintenance, envelope, and conserved hypothetical proteins.

scholarly journals Physiological Evidence for Isopotential Tunneling in the Electron Transport Chain of Methane-Producing Archaea

2017 ◽  
Vol 83 (18) ◽  
Author(s):  
Nikolas Duszenko ◽  
Nicole R. Buan
Keyword(s):  
Escherichia Coli ◽  
Electron Transport ◽  
Stationary Phase ◽  
Exponential Growth ◽  
Electron Transport Chain ◽  
Methanosarcina Barkeri ◽  
Metabolic Efficiency ◽  
Methanosarcina Acetivorans ◽  
Content Type ◽  
Transport Chain

ABSTRACT Many, but not all, organisms use quinones to conserve energy in their electron transport chains. Fermentative bacteria and methane-producing archaea (methanogens) do not produce quinones but have devised other ways to generate ATP. Methanophenazine (MPh) is a unique membrane electron carrier found in Methanosarcina species that plays the same role as quinones in the electron transport chain. To extend the analogy between quinones and MPh, we compared the MPh pool sizes between two well-studied Methanosarcina species, Methanosarcina acetivorans C2A and Methanosarcina barkeri Fusaro, to the quinone pool size in the bacterium Escherichia coli. We found the quantity of MPh per cell increases as cultures transition from exponential growth to stationary phase, and absolute quantities of MPh were 3-fold higher in M. acetivorans than in M. barkeri. The concentration of MPh suggests the cell membrane of M. acetivorans, but not of M. barkeri, is electrically quantized as if it were a single conductive metal sheet and near optimal for rate of electron transport. Similarly, stationary (but not exponentially growing) E. coli cells also have electrically quantized membranes on the basis of quinone content. Consistent with our hypothesis, we demonstrated that the exogenous addition of phenazine increases the growth rate of M. barkeri three times that of M. acetivorans. Our work suggests electron flux through MPh is naturally higher in M. acetivorans than in M. barkeri and that hydrogen cycling is less efficient at conserving energy than scalar proton translocation using MPh. IMPORTANCE Can we grow more from less? The ability to optimize and manipulate metabolic efficiency in cells is the difference between commercially viable and nonviable renewable technologies. Much can be learned from methane-producing archaea (methanogens) which evolved a successful metabolic lifestyle under extreme thermodynamic constraints. Methanogens use highly efficient electron transport systems and supramolecular complexes to optimize electron and carbon flow to control biomass synthesis and the production of methane. Worldwide, methanogens are used to generate renewable methane for heat, electricity, and transportation. Our observations suggest Methanosarcina acetivorans, but not Methanosarcina barkeri, has electrically quantized membranes. Escherichia coli, a model facultative anaerobe, has optimal electron transport at the stationary phase but not during exponential growth. This study also suggests the metabolic efficiency of bacteria and archaea can be improved using exogenously supplied lipophilic electron carriers. The enhancement of methanogen electron transport through methanophenazine has the potential to increase renewable methane production at an industrial scale.

scholarly journals In Bacillus subtilis LutR is part of the global complex regulatory network governing the adaptation to the transition from exponential growth to stationary phase

Microbiology ◽  
2014 ◽  
Vol 160 (2) ◽  
pp. 243-260 ◽  
Author(s):  
Öykü İrigül-Sönmez ◽  
Türkan E. Köroğlu ◽  
Büşra Öztürk ◽  
Ákos T. Kovács ◽  
Oscar P. Kuipers ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Stationary Phase ◽  
Exponential Growth ◽  
Dna Microarrays ◽  
Antibiotic Production ◽  
Transcriptional Profiling ◽  
Mobility Shift ◽  
Carbohydrate Utilization ◽  
Altered Expression ◽  
Gel Mobility Shift

The lutR gene, encoding a product resembling a GntR-family transcriptional regulator, has previously been identified as a gene required for the production of the dipeptide antibiotic bacilysin in Bacillus subtilis. To understand the broader regulatory roles of LutR in B. subtilis, we studied the genome-wide effects of a lutR null mutation by combining transcriptional profiling studies using DNA microarrays, reverse transcription quantitative PCR, lacZ fusion analyses and gel mobility shift assays. We report that 65 transcriptional units corresponding to 23 mono-cistronic units and 42 operons show altered expression levels in lutR mutant cells, as compared with lutR + wild-type cells in early stationary phase. Among these, 11 single genes and 25 operons are likely to be under direct control of LutR. The products of these genes are involved in a variety of physiological processes associated with the onset of stationary phase in B. subtilis, including degradative enzyme production, antibiotic production and resistance, carbohydrate utilization and transport, nitrogen metabolism, phosphate uptake, fatty acid and phospholipid biosynthesis, protein synthesis and translocation, cell-wall metabolism, energy production, transfer of mobile genetic elements, induction of phage-related genes, sporulation, delay of sporulation and cannibalism, and biofilm formation. Furthermore, an electrophoretic mobility shift assay performed in the presence of both SinR and LutR revealed a close overlap between the LutR and SinR targets. Our data also revealed a significant overlap with the AbrB regulon. Together, these findings reveal that LutR is part of the global complex, interconnected regulatory systems governing adaptation of bacteria to the transition from exponential growth to stationary phase.

Quantitative profiling and dynamics of mRNA modifications in Escherichia coli

2021 ◽  
Author(s):  
Dimitar Plamenov Petrov ◽  
Steffen Kaiser ◽  
Stefanie Kaiser ◽  
Kirsten Jung
Keyword(s):  
Mass Spectrometry ◽  
Escherichia Coli ◽  
Stationary Phase ◽  
Exponential Growth ◽  
Gel Electrophoresis ◽  
E Coli ◽  
Physiological Processes ◽  
Mrna Methylation ◽  
Important Regulator ◽  
Quantitative Profiling

mRNA methylation is an important regulator of many physiological processes in eukaryotes but has not been studied in depth in prokaryotes. In contrast to the large number of eukaryotic mRNA modifications that have been described, N6-methyladenosine (m6A) is the only modification of bacterial mRNA identified to date. Here, we used a gel electrophoresis-based RNA separation method and quantitatively analyzed the mRNA-specific modification profile of Escherichia coli using mass spectrometry. In addition to m6A, we provide evidence for the presence of 7-methylguanosine (m7G), and we found first hints for 5-methylcytidine (m5C), N6,N6-dimethyladenosine (m6,6A), 1-methylguanosine (m1G), 5-methyluridine (m5U), and pseudouridine (Ψ) in the mRNA of E. coli, which implies that E. coli has a complex mRNA modification pattern. Furthermore, we observed changes in the abundance of some mRNA modifications during the transition of E. coli from the exponential growth to the stationary phase as well as upon exposure to stress. This study reveals a previously underestimated level of regulation between transcription and translation in bacteria.

scholarly journals Biophysical Properties of Escherichia coli Cytoplasm in Stationary Phase by Superresolution Fluorescence Microscopy

mBio ◽  
2020 ◽  
Vol 11 (3) ◽  
Author(s):  
Yanyu Zhu ◽  
Mainak Mustafi ◽  
James C. Weisshaar
Keyword(s):  
Escherichia Coli ◽  
Fluorescence Microscopy ◽  
Rna Polymerase ◽  
Stationary Phase ◽  
Exponential Growth ◽  
Mean Square Displacement ◽  
Quiescent State ◽  
Chromosomal Dna ◽  
Content Type ◽  
E Coli

ABSTRACT In nature, bacteria must survive long periods of nutrient deprivation while maintaining the ability to recover and grow when conditions improve. This quiescent state is called stationary phase. The biochemistry of Escherichia coli in stationary phase is reasonably well understood. Much less is known about the biophysical state of the cytoplasm. Earlier studies of harvested nucleoids concluded that the stationary-phase nucleoid is “compacted” or “supercompacted,” and there are suggestions that the cytoplasm is “glass-like.” Nevertheless, stationary-phase bacteria support active transcription and translation. Here, we present results of a quantitative superresolution fluorescence study comparing the spatial distributions and diffusive properties of key components of the transcription-translation machinery in intact E. coli cells that were either maintained in 2-day stationary phase or undergoing moderately fast exponential growth. Stationary-phase cells are shorter and exhibit strong heterogeneity in cell length, nucleoid volume, and biopolymer diffusive properties. As in exponential growth, the nucleoid and ribosomes are strongly segregated. The chromosomal DNA is locally more rigid in stationary phase. The population-weighted average of diffusion coefficients estimated from mean-square displacement plots is 2-fold higher in stationary phase for both RNA polymerase (RNAP) and ribosomal species. The average DNA density is roughly twice as high as that in cells undergoing slow exponential growth. The data indicate that the stationary-phase nucleoid is permeable to RNAP and suggest that it is permeable to ribosomal subunits. There appears to be no need to postulate migration of actively transcribed genes to the nucleoid periphery. IMPORTANCE Bacteria in nature usually lack sufficient nutrients to enable growth and replication. Such starved bacteria adapt into a quiescent state known as the stationary phase. The chromosomal DNA is protected against oxidative damage, and ribosomes are stored in a dimeric structure impervious to digestion. Stationary-phase bacteria can recover and grow quickly when better nutrient conditions arise. The biochemistry of stationary-phase E. coli is reasonably well understood. Here, we present results from a study of the biophysical state of starved E. coli. Superresolution fluorescence microscopy enables high-resolution location and tracking of a DNA locus and of single copies of RNA polymerase (the transcription machine) and ribosomes (the translation machine) in intact E. coli cells maintained in stationary phase. Evidently, the chromosomal DNA remains sufficiently permeable to enable transcription and translation to occur. This description contrasts with the usual picture of a rigid stationary-phase cytoplasm with highly condensed DNA.

scholarly journals The Growth Advantage in Stationary-Phase PhenotypeConferred by rpoS Mutations Is Dependent on the pH andNutrientEnvironment

2003 ◽  
Vol 185 (24) ◽  
pp. 7044-7052 ◽  
Author(s):  
Michael J. Farrell ◽  
Steven E. Finkel
Keyword(s):  
Stationary Phase ◽  
Batch Culture ◽  
Environmental Conditions ◽  
Sole Source ◽  
Culture Conditions ◽  
Luria Bertani ◽  
Relative Fitness ◽  
Wild Type ◽  
Fitness Advantage ◽  
Casamino Acids

ABSTRACT Escherichia coli cells that are aged in batch culture display an increased fitness referred to as the growth advantage in stationary phase, or GASP, phenotype. A common early adaptation to this culture environment is a mutant rpoS allele, such as rpoS819, that results in attenuated RpoS activity. However, it is important to note that during long-term batch culture, environmental conditions are in flux. To date, most studies of the GASP phenotype have focused on identifying alleles that render an advantage in a specific environment, Luria-Bertani broth (LB) batch culture. To determine what role environmental conditions play in rendering relative fitness advantages to E. coli cells carrying either the wild-type or rpoS819 alleles, we performed competitions under a variety of culture conditions in which either the available nutrients, the pH, or both were manipulated. In LB medium, we found that while the rpoS819 allele confers a strong competitive fitness advantage at basic pH, it confers a reduced advantage under neutral conditions, and it is disadvantageous under acidic conditions. Similar results were found using other media. rpoS819 conferred its greatest advantage in basic minimal medium in which either glucose or Casamino Acids were the sole source of carbon and energy. In acidic medium supplemented with either Casamino Acids or glucose, the wild-type allele conferred a slight advantage. In addition, populations were dynamic under all pH conditions tested, with neither the wild-type nor mutant rpoS alleles sweeping a culture. We also found that the strength of the fitness advantage gained during a 10-day incubation is pH dependent.

scholarly journals The mannophosphoinositides of Corynebacterium aquaticum

1975 ◽  
Vol 148 (2) ◽  
pp. 253-258 ◽  
Author(s):  
J A Hackett ◽  
P J Brennan
Keyword(s):  
Stationary Phase ◽  
Exponential Growth ◽  
Growth Cycle ◽  
Exponential Phase ◽  
Late Stationary Phase ◽  
Late Exponential Phase

Besides the monomannophosphoinositide previously reported in Corynebacterium aquaticum small amounts of other, apparently more glycosylated, mannophosphoinositides have been identified in stationary phase cells. Moreover, by labelling cells with [32P]Pi, phosphatidylinositol was found, comprising about 1.5% of the stationary-phase phospholipids. 2. Pulse-chase experiments performed on cells in the late exponential phase of growth further suggested the sequence phosphatidylinositol leads to monomannophosphoinositide as the first step in the biosynthesis of the mannophosphoinositides. 3. Di-and tri-mannophosphoinositides are apparently the main mannophosphoinositides present during exponential growth. Monomannophosphoinositide predominates only in late stationary phase; in the earlier stationary phase, phosphatidylinositol comprises 50% of the phosphoinositide lipid, and tetramannophosphoinositide constitutes much of the remainder. 4. The metabolism and functions of the mannophosphoinositides are discussed, particularly in relation to changes in their composition throughout the growth cycle.

Factors favouring the accumulation of arabinitol in the yeast Debaryomyces hansenii

1985 ◽  
Vol 31 (5) ◽  
pp. 467-471 ◽  
Author(s):  
M. Fernanda Nobre ◽  
Milton S. da Costa
Keyword(s):  
Stationary Phase ◽  
Carbon Sources ◽  
Debaryomyces Hansenii ◽  
Basal Medium ◽  
Culture Conditions ◽  
Glucose Medium ◽  
Intracellular Accumulation ◽  
Initial Glucose Concentration ◽  
Exogenous Glucose ◽  
Low Concentrations

Culture conditions which lead to the intracellular accumulation of arabinitol were investigated in Debaryomyces hansenii. Arabinitol, detected in very low concentrations during the exponential phase of growth, accumulated during the stationary phase of growth in yeast extract – peptone – 1% (w/v) glucose medium. This polyol was retained intracellularly even after depletion of exogenous glucose, but was rapidly depleted during regrowth in fresh glucose medium. The accumulation of arabinitol was also favoured in media containing 1% (w/v) D-fructose, sucrose, L-arabinose, glycerol, and sodium acetate. High mannitol levels accumulated in stationary phase cells derived from growth in 1% (w/v) D-mannitol, and in these cultures only traces of arabinitol were detectable. Intracellular mannitol was also retained after the extracellular mannitol had been consumed, and was rapidly depleted during regrowth in glucose medium. Arabinitol did not accumulate in basal medium with no added carbon source, nor in media with nonmetabolizable carbon sources (D-arabinose or D-ribose). On the other hand, arabinitol accumulation was independent of the initial glucose concentration between 1% (w/v) and about 9% (w/v).

scholarly journals Peptidoglycan Recycling in Gram-Positive Bacteria Is Crucial for Survival in Stationary Phase

mBio ◽  
2016 ◽  
Vol 7 (5) ◽  
Author(s):  
Marina Borisova ◽  
Rosmarie Gaupp ◽  
Amanda Duckworth ◽  
Alexander Schneider ◽  
Désirée Dalügge ◽  
...  
Keyword(s):  
Cell Wall ◽  
Stationary Phase ◽  
Exponential Growth ◽  
Model Organisms ◽  
Exponential Growth Phase ◽  
Rich Medium ◽  
Late Stationary Phase ◽  
Gram Positive ◽  
Term Survival ◽  
Gram Positive Bacteria

ABSTRACTPeptidoglycan recycling is a metabolic process by which Gram-negative bacteria reutilize up to half of their cell wall within one generation during vegetative growth. Whether peptidoglycan recycling also occurs in Gram-positive bacteria has so far remained unclear. We show here that three Gram-positive model organisms,Staphylococcus aureus,Bacillus subtilis, andStreptomyces coelicolor, all recycle the sugarN-acetylmuramic acid (MurNAc) of their peptidoglycan during growth in rich medium. They possess MurNAc-6-phosphate (MurNAc-6P) etherase (MurQ inE. coli) enzymes, which are responsible for the intracellular conversion of MurNAc-6P toN-acetylglucosamine-6-phosphate andd-lactate. By applying mass spectrometry, we observed accumulation of MurNAc-6P in MurNAc-6P etherase deletion mutants but not in either the isogenic parental strains or complemented strains, suggesting that MurQ orthologs are required for the recycling of cell wall-derived MurNAc in these bacteria. Quantification of MurNAc-6P in ΔmurQcells ofS. aureusandB. subtilisrevealed small amounts during exponential growth phase (0.19 nmol and 0.03 nmol, respectively, per ml of cells at an optical density at 600 nm [OD600] of 1) but large amounts during transition (0.56 nmol and 0.52 nmol) and stationary (0.53 nmol and 1.36 nmol) phases. The addition of MurNAc to ΔmurQcultures greatly increased the levels of intracellular MurNAc-6P in all growth phases. The ΔmurQmutants ofS. aureusandB. subtilisshowed no growth deficiency in rich medium compared to the growth of the respective parental strains, but intriguingly, they had a severe survival disadvantage in late stationary phase. Thus, although peptidoglycan recycling is apparently not essential for the growth of Gram-positive bacteria, it provides a benefit for long-term survival.IMPORTANCEThe peptidoglycan of the bacterial cell wall is turned over steadily during growth. As peptidoglycan fragments were found in large amounts in spent medium of exponentially growing Gram-positive bacteria, their ability to recycle these fragments has been questioned. We conclusively showed recycling of the peptidoglycan component MurNAc in different Gram-positive model organisms and revealed that a MurNAc-6P etherase (MurQ or MurQ ortholog) enzyme is required in this process. We further demonstrated that recycling occurs predominantly during the transition to stationary phase inS. aureusandB. subtilis, explaining why peptidoglycan fragments are found in the medium during exponential growth. We quantified the intracellular accumulation of recycling products in MurNAc-6P etherase gene mutants, revealing that about 5% and 10% of the MurNAc of the cell wall per generation is recycled inS. aureusandB. subtilis, respectively. Importantly, we showed that MurNAc recycling and salvaging does not sustain growth in these bacteria but is used to enhance survival during late stationary phase.

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