Etude de deux mutants du métabolisme du glycérol chez Bacillus subtilis

1972 ◽  
Vol 18 (8) ◽  
pp. 1315-1325 ◽  
Author(s):  
S. A. Saheb
Keyword(s):  
Bacillus Subtilis ◽  
Carbon Source ◽  
Wild Strain ◽  
Glycerol Kinase ◽  
Glycerol Dehydrogenase ◽  
Dihydroxyacetone Phosphate ◽  
Microbial Species ◽  
Glycerophosphate Dehydrogenase ◽  
Dihydroxyacetone Kinase

As in different microbial species, two pathways for the degradation of glycerol are found in B. subtilis 168. Each pathway includes two enzymes which can catalyze the formation of dihydroxyacetone phosphate from glycerol in vitro. The first pathway includes a glycerol dehydrogenase (gl-D) and a dihydroxyacetone kinase (dha-K). The second pathway includes a glycerol kinase (gl-K) and an α-glycerophosphate dehydrogenase (glp-D). Enzymes of both pathways are repressed in the presence of glucose. Only the enzymes of the second pathway are inducible. The inducer is probably glycerophosphate, utilization of which as a carbon source by B. subtilis is demonstrated. Degradation of glycerol in B. subtilis proceeds through the second pathway. This was demonstrated by the isolation of a mutant (gl−2) impaired in glycerol kinase, and which cannot use glycerol as a carbon source. Another mutant (gl−1)was isolated, which cannot use glycerol as a carbon source. When comparing the activity of the four enzymes, particularly gl-K, no significant differences were observed between the wild strain and the mutant gl−1. This leads one to consider the existence of a glycerol permeation system in B. subtilis. A mutation affecting this system would explain the behavior of the mutant gl−1.

Glycerol metabolism in Rhizobium

1976 ◽  
Vol 22 (2) ◽  
pp. 150-153 ◽  
Author(s):  
A. Arias ◽  
G. Martinez-Drets
Keyword(s):  
Metabolic Pathway ◽  
Glycerol Kinase ◽  
Rhizobium Japonicum ◽  
Glycerol Dehydrogenase ◽  
Glycerol Metabolism ◽  
Glycerophosphate Dehydrogenase ◽  
Slow Growing

Four strains of Rhizobium japonicum and one strain of R. trifolii were grown on glycerol and found to contain a soluble ATP-glycerol kinase and a particulate glycerophosphate dehydrogenase. Both enzymes are induced by glycerol. The presence of NAD+– or NADP+–glycerol dehydrogenase was not detected in any of the strains. No significant differences were found in the glycerol metabolic pathway between fast- and slow-growing rhizobia.

scholarly journals Triosephosphate Isomerase Is Dispensable In Vitro yet Essential for Mycobacterium tuberculosis To Establish Infection

mBio ◽  
2014 ◽  
Vol 5 (2) ◽  
Author(s):  
Carolina Trujillo ◽  
Antje Blumenthal ◽  
Joeli Marrero ◽  
Kyu Y. Rhee ◽  
Dirk Schnappinger ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Carbon Source ◽  
Triosephosphate Isomerase ◽  
Central Carbon Metabolism ◽  
Dihydroxyacetone Phosphate ◽  
Content Type ◽  
Carbon Substrates ◽  
Metabolic Conditions ◽  
Single Carbon Source

ABSTRACTTriosephosphate isomerase (TPI) catalyzes the interconversion of dihydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate (G3P). This reaction is required for glycolysis and gluconeogenesis, andtpihas been predicted to be essential for growth ofMycobacterium tuberculosis. However, when studying a conditionally regulatedtpiknockdown mutant, we noticed that depletion of TPI reduced growth ofM. tuberculosisin media containing a single carbon source but not in media that contained both a glycolytic and a gluconeogenic carbon source. We used such two-carbon-source media to isolate atpideletion (Δtpi) mutant. The Δtpimutant did not survive with single carbon substrates but grew like wild-type (WT)M. tuberculosisin the presence of both a glycolytic and a gluconeogenic carbon source.13C metabolite tracing revealed the accumulation of TPI substrates in Δtpiand the absence of alternative triosephosphate isomerases and metabolic bypass reactions, which confirmed the requirement of TPI for glycolysis and gluconeogenesis inM. tuberculosis. The Δtpistrain was furthermore severely attenuated in the mouse model of tuberculosis, suggesting thatM. tuberculosiscannot simultaneously access sufficient quantities of glycolytic and gluconeogenic carbon substrates to establish infection in mice.IMPORTANCEThe importance of central carbon metabolism for the pathogenesis ofM. tuberculosishas recently been recognized, but the consequences of depleting specific metabolic enzymes remain to be identified for many enzymes. We investigated triosephosphate isomerase (TPI) because it is central to both glycolysis and gluconeogenesis and had been predicted to be essential for growth ofM. tuberculosis. This work identified metabolic conditions that make TPI dispensable forM. tuberculosisgrowth in culture and proved thatM. tuberculosisrelies on a single TPI enzyme and has no metabolic bypass for the TPI-dependent interconversion of dihydroxyacetone phosphate and glyceraldehyde-3-phosphate in glycolysis and gluconeogenesis. Finally, we demonstrate that TPI is essential for growth of the pathogen in mouse lungs.

Perméation du glycérol et sporulation chez Bacillus subtilis

1972 ◽  
Vol 18 (8) ◽  
pp. 1307-1313 ◽  
Author(s):  
S. A. Saheb
Keyword(s):  
Bacillus Subtilis ◽  
Wild Strain ◽  
Glycerol Kinase ◽  
Simple Diffusion ◽  
Intracellular Pool ◽  
Mutant Cells

Glycerol permeation was studied in B. subtilis 168 trp− gl+ and its two mutants gl−1 and gl−2. The mutant gl−1 has all the enzymes required for the degradation of endocellular glycerol. The mutant gl−2 is impaired in the enzyme glycerol kinase. In the presence of increasing concentrations of glycerol-14C, incorporation of radioactivity by the wild strain obeys Michaelis law while it is linear in the case of the mutant gl−1. Thus the mutant gl−1 is cryptic towards glycerol. No evidence was found as to the formation of an intracellular pool of glycerol in any of the three strains (gl+, gl−1, gl−2) studied. This result suggests that permeation of glycerol in B. subtilis is probably facilitated by diffusion. Sporulation of the mutant gl−1 in presence of glycerol is explained by a mutation affecting the permeation system. Thus glycerol enters in the mutant cells by simple diffusion. As a consequence, the metabolism is greatly reduced and the sporulation mechanism is triggered.

The Bacillus subtilis YufLM two-component system regulates the expression of the malate transporters MaeN (YufR) and YflS, and is essential for utilization of malate in minimal medium

Microbiology ◽  
2003 ◽  
Vol 149 (9) ◽  
pp. 2317-2329 ◽  
Author(s):  
Kousei Tanaka ◽  
Kazuo Kobayashi ◽  
Naotake Ogasawara
Keyword(s):  
Bacillus Subtilis ◽  
Carbon Source ◽  
Sole Carbon Source ◽  
Constitutive Expression ◽  
Tca Cycle ◽  
Regulatory Systems ◽  
The Tca Cycle ◽  
Two Component ◽  
Tca Cycle Intermediates

The Gram-positive bacterium Bacillus subtilis has a complete set of enzymes for the tricarboxylic acid (TCA) cycle and can grow aerobically using most of the TCA cycle intermediates (malate, fumarate, succinate and citrate) as a sole carbon source. The B. subtilis genome sequence contains three paralogous two-component regulatory systems, CitST, DctSR and YufLM. CitST and DctSR activate the expression of a transporter of the Mg2+–citrate complex (CitM) and a fumarate and succinate transporter (DctP), respectively. These findings prompted an investigation of whether the YufL sensor and its cognate regulator, YufM, play a role in malate uptake. This paper reports that the YufM regulator shows in vitro binding to the promoter region of two malate transporter genes, maeN and yflS, and is responsible for inducing their expression in vivo. It was also found that inactivation of the yufM or maeN genes resulted in bacteria that could not grow in a minimal salts medium containing malate as a sole carbon source, indicating that the induction of the MaeN transporter by the YufM regulator is essential for the utilization of malate as a carbon source. Inactivation of the yufL gene resulted in the constitutive expression of MaeN. This expression was suppressed by reintroduction of the kinase domain of YufL, indicating that the YufL sensor is required for proper signal detection and signalling specificity. The authors propose that a phosphatase activity of YufL plays an important role in the YufLM two-component regulatory system. The studies reported here have revealed that members of a set of paralogous two-component regulatory systems in B. subtilis, CitST, DctSR and YufLM, are involved in a related function – uptake (and metabolism) of the TCA cycle intermediates – but with distinct substrate specificities.

scholarly journals Transcriptional Activation of the Bacillus subtilis ackA Gene Requires Sequences Upstream of the Promoter

1998 ◽  
Vol 180 (22) ◽  
pp. 5961-5967 ◽  
Author(s):  
Andrew J. Turinsky ◽  
Frank J. Grundy ◽  
Jeong-Ho Kim ◽  
Glenn H. Chambliss ◽  
Tina M. Henkin
Keyword(s):  
Bacillus Subtilis ◽  
Carbon Source ◽  
Transcriptional Activation ◽  
Consensus Sequence ◽  
Protein A ◽  
Acetate Kinase ◽  
Gene Encoding ◽  
Gram Positive Bacteria ◽  
Catabolite Control Protein A

ABSTRACT Transcriptional activation of the Bacillus subtilis ackA gene, encoding acetate kinase, was previously shown to require catabolite control protein A (CcpA) and sequences upstream of the ackA promoter. CcpA, which is responsible for catabolite repression of a number of secondary carbon source utilization genes in B. subtilis and other gram-positive bacteria, recognizes a cis-acting consensus sequence, designated cre (catabolite response element), generally located within or downstream of the promoter of the repressed gene. Two sites resembling this sequence are centered at positions −116.5 and −56.5 of the ackA promoter and have been termedcre1 and cre2, respectively. Synthesis of acetate kinase, which is involved in the conversion of acetyl coenzyme A to acetate, is induced when cells are grown in the presence of an easily metabolized carbon source such as glucose. In this study,cre2, the site closer to the promoter, and the region upstream of cre2 were shown to be indispensable for CcpA-dependent transcriptional activation of ackA, whereascre1 was not required. In addition, insertion of 5 bp between cre2 and the promoter disrupted activation, while 10 bp was tolerated, suggesting face-of-the-helix dependence of the position of cre2 and/or upstream sequences. DNase footprinting experiments demonstrated binding of CcpA in vitro tocre2 but not cre1, consistent with the genetic data. Activation of ackA transcription was blocked in aptsH1/crh double mutant, suggesting involvement of this pathway in CcpA-mediated transcriptional activation.

THE EFFECT OF FASTING ON ESTERIFICATION OF PALMITATE BY RAT LIVER IN VITRO

1966 ◽  
Vol 44 (1) ◽  
pp. 129-140 ◽  
Author(s):  
Bernard Rubenstein ◽  
David Rubinstein
Keyword(s):  
Rat Liver ◽  
Incubation Medium ◽  
Intact Cell ◽  
Glycerol Kinase ◽  
Glycerophosphate Dehydrogenase ◽  
Liver Slices ◽  
Liver Homogenates

The ability of liver slices from rats fasted 48 hours to esterify palmitate-1-14C is about half of that of slices from fed animals. The same effect can be observed in homogenates of liver freed of nuclei, either with or without mitochondria. In both preparations, the synthesis of triglycerides is chiefly affected. The decrease in esterification by homogenate supernatants containing microsomes from fasted animals can be overcome by using increased amounts of ATP or an ATP generator and NaF in the incubation medium. The ATPase responsible for the higher ATP requirement in liver homogenates from fasted animals is Mg++-dependent. Higher concentrations of ATP inhibit esterification by mitochondrial preparations. Incorporation of both palmitate-9-10-3H and of glycerol-1-3-14C is reduced to the same extent for each compound in slices from fasting animals. Glycerol kinase and α-glycerophosphate dehydrogenase are both unaffected by 48 hours' fasting. It is concluded that the decrease in ATP from the activation of ATPase is responsible for the decreased esterification in the intact cell.

scholarly journals Glycerol Is Metabolized in a Complex and Strain-Dependent Manner in Enterococcus faecalis

2009 ◽  
Vol 192 (3) ◽  
pp. 779-785 ◽  
Author(s):  
Alain Bizzini ◽  
Chen Zhao ◽  
Aurélie Budin-Verneuil ◽  
Nicolas Sauvageot ◽  
Jean-Christophe Giard ◽  
...  
Keyword(s):  
Gene Expression ◽  
Enterococcus Faecalis ◽  
Glycerol Dehydrogenase ◽  
Dihydroxyacetone Phosphate ◽  
Dependent Manner ◽  
Anaerobic Conditions ◽  
Dihydroxyacetone Kinase ◽  
Aerobic And Anaerobic ◽  
Strain Dependent ◽  
Aerobic And Anaerobic Conditions

ABSTRACT Enterococcus faecalis is equipped with two pathways of glycerol dissimilation. Glycerol can either first be phosphorylated by glycerol kinase and then oxidized by glycerol-3-phosphate oxidase (the glpK pathway) or first be oxidized by glycerol dehydrogenase and then phosphorylated by dihydroxyacetone kinase (the dhaK pathway). Both pathways lead to the formation of dihydroxyacetone phosphate, an intermediate of glycolysis. It was assumed that the glpK pathway operates during aerobiosis and that the dhaK pathway operates under anaerobic conditions. Because this had not been analyzed by a genetic study, we constructed mutants of strain JH2-2 affected in both pathways. The growth of these mutants on glycerol under aerobic and anaerobic conditions was monitored. In contrast to the former model, results strongly suggest that glycerol is catabolized simultaneously by both pathways in the E. faecalis JH2-2 strain in the presence of oxygen. In accordance with the former model, glycerol is metabolized by the dhaK pathway under anaerobic conditions. Comparison of different E. faecalis isolates revealed an impressive diversity of growth behaviors on glycerol. Analysis by BLAST searching and real-time reverse transcriptase PCR revealed that this diversity is based not on different gene contents but rather on differences in gene expression. Some strains used preferentially the glpK pathway whereas others probably exclusively the dhaK pathway under aerobic conditions. Our results demonstrate that the species E. faecalis cannot be represented by only one model of aerobic glycerol catabolism.

Antagonistic activity of Bacillus subtilis strains isolated from various sources

2018 ◽  
Vol 8 (2) ◽  
pp. 354-364
Author(s):  
A. N. Irkitova ◽  
A. V. Grebenshchikova ◽  
A. V. Matsyura
Keyword(s):  
Escherichia Coli ◽  
Bacillus Subtilis ◽  
Wild Strain ◽  
Fish Farming ◽  
Antagonistic Activity ◽  
Antagonistic Effect ◽  
E Coli ◽  
Long Period ◽  
Test Culture ◽  
Agar Media

<p>An important link in solving the problem of healthy food is the intensification of the livestock, poultry and fish farming, which is possible only in the adoption and rigorous implementation of the concept of rational feeding of animals. In the implementation of this concept required is the application of probiotic preparations. Currently, there is an increased interest in spore probiotics. In many ways, this can be explained by the fact that they use no vegetative forms of the bacilli and their spores. This property provides spore probiotics a number of advantages: they are not whimsical, easily could be selected, cultivated, and dried. Moreover, they are resistant to various factors and could remain viable during a long period. One of the most famous spore microorganisms, which are widely used in agriculture, is <em>Bacillus subtilis</em>. Among the requirements imposed to probiotic microorganisms is mandatory – antagonistic activity to pathogenic and conditional-pathogenic microflora. The article presents the results of the analysis of antagonistic activity of collection strains of <em>B. subtilis</em>, and strains isolated from commercial preparations. We studied the antagonistic activity on agar and liquid nutrient medias to trigger different antagonism mechanisms of <em>B. subtilis</em>. On agar media, we applied three diffusion methods: perpendicular bands, agar blocks, agar wells. We also applied the method of co-incubating the test culture (<em>Escherichia coli</em>) and the antagonist (or its supernatant) in the nutrient broth. Our results demonstrated that all our explored strains of <em>B. subtilis</em> have antimicrobial activity against a wild strain of <em>E. coli</em>, but to varying degrees. We identified strains of <em>B. subtilis</em> with the highest antagonistic effect that can be recommended for inclusion in microbial preparations for agriculture.</p><p><em><br /></em><em></em></p>

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