scholarly journals Azotobacter vinelandii Aldehyde Dehydrogenase Regulated by ς54: Role in Alcohol Catabolism and Encystment

2001 ◽  
Vol 183 (21) ◽  
pp. 6169-6174 ◽  
Author(s):  
Socorro Gama-Castro ◽  
Cinthia Núñez ◽  
Daniel Segura ◽  
Soledad Moreno ◽  
Josefina Guzmán ◽  
...  
Keyword(s):  
Carbon Source ◽  
Aldehyde Dehydrogenase ◽  
Bacterial Growth ◽  
Sole Carbon Source ◽  
Azotobacter Vinelandii ◽  
Gene Encoding ◽  
In Cells

ABSTRACT Encystment in Azotobacter vinelandii is induced byn-butanol or β-hydroxybutyrate (BHB). We identified a gene, encoding an aldehyde dehydrogenase, that was namedaldA. An aldA mutation impaired bacterial growth on n-butanol, ethanol, or hexanol as the sole carbon source. Expression of aldA increased in cells shifted from sucrose to n-butanol and was shown to be dependent on the alternative ς54 factor. A mutation in rpoNencoding the ς54 factor also impaired growth on alcohols. Encystment on n-butanol, but not on BHB, was impaired inaldA or rpoN mutants, indicating thatn-butanol is not an inducer of encystment by itself but must be catabolized in order to induce encystment.

scholarly journals Isolation and Characterization of a Mutant of the Marine Bacterium Alcanivorax borkumensis SK2 Defective in Lipid Biosynthesis

2010 ◽  
Vol 76 (9) ◽  
pp. 2884-2894 ◽  
Author(s):  
Efraín Manilla-Pérez ◽  
Alvin Brian Lange ◽  
Stephan Hetzler ◽  
Marc Wältermann ◽  
Rainer Kalscheuer ◽  
...  
Keyword(s):  
Carbon Source ◽  
Sole Carbon Source ◽  
Marine Bacterium ◽  
Neutral Lipids ◽  
Nile Red ◽  
Dry Weight ◽  
Wax Ester ◽  
Gene Encoding ◽  
Isolation And Characterization ◽  
Key Enzyme

ABSTRACT In many microorganisms, the key enzyme responsible for catalyzing the last step in triacylglycerol (TAG) and wax ester (WE) biosynthesis is an unspecific acyltransferase which is also referred to as wax ester synthase/acyl coenzyme A (acyl-CoA):diacylglycerol acyltransferase (WS/DGAT; AtfA). The importance and function of two AtfA homologues (AtfA1 and AtfA2) in the biosynthesis of TAGs and WEs in the hydrocarbon-degrading marine bacterium Alcanivorax borkumensis SK2 have been described recently. However, after the disruption of both the AtfA1 and AtfA2 genes, reduced but substantial accumulation of TAGs was still observed, indicating the existence of an alternative TAG biosynthesis pathway. In this study, transposon-induced mutagenesis was applied to an atfA1 atfA2 double mutant to screen for A. borkumensis mutants totally defective in biosynthesis of neutral lipids in order to identify additional enzymes involved in the biosynthesis of these lipids. At the same time, we have searched for a totally TAG-negative mutant in order to study the function of TAGs in A. borkumensis. Thirteen fluorescence-negative mutants were identified on Nile red ONR7a agar plates and analyzed for their abilities to synthesize lipids. Among these, mutant 2 M131 was no longer able to synthesize and accumulate TAGs if pyruvate was used as the sole carbon source. The transposon insertion was localized in a gene encoding a putative cytochrome c family protein (ABO_1185). Growth and TAG accumulation experiments showed that the disruption of this gene resulted in the absence of TAGs in 2 M131 but that growth was not affected. In cells of A. borkumensis SK2 grown on pyruvate as the sole carbon source, TAGs represented about 11% of the dry weight of the cells, while in the mutant 2 M131, TAGs were not detected by thin-layer and gas chromatography analyses. Starvation and lipid mobilization experiments revealed that the lipids play an important role in the survival of the cells. The function of neutral lipids in A. borkumensis SK2 is discussed.

scholarly journals Enhanced Bacterial Growth and Gene Expression of D-Amino Acid Dehydrogenase With D-Glutamate as the Sole Carbon Source

2018 ◽  
Vol 9 ◽  
Author(s):  
Takeshi Naganuma ◽  
Yoshiakira Iinuma ◽  
Hitomi Nishiwaki ◽  
Ryota Murase ◽  
Kazuo Masaki ◽  
...  
Keyword(s):  
Gene Expression ◽  
Amino Acid ◽  
Carbon Source ◽  
Bacterial Growth ◽  
Sole Carbon Source ◽  
Acid Dehydrogenase ◽  
Amino Acid Dehydrogenase

scholarly journals Hidden resources in the Escherichia coli genome restore PLP synthesis and robust growth after deletion of the essential gene pdxB

2019 ◽  
Vol 116 (48) ◽  
pp. 24164-24173 ◽  
Author(s):  
Juhan Kim ◽  
Jake J. Flood ◽  
Michael R. Kristofich ◽  
Cyrus Gidfar ◽  
Andrew B. Morgenthaler ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Carbon Source ◽  
Sole Carbon Source ◽  
Essential Gene ◽  
Alternative Pathway ◽  
Gene Encoding ◽  
Genes Encoding ◽  
Phosphoglycerate Dehydrogenase ◽  
Functional Pathway

PdxB (erythronate 4-phosphate dehydrogenase) is expected to be required for synthesis of the essential cofactor pyridoxal 5′-phosphate (PLP) in Escherichia coli. Surprisingly, incubation of the ∆pdxB strain in medium containing glucose as a sole carbon source for 10 d resulted in visible turbidity, suggesting that PLP is being produced by some alternative pathway. Continued evolution of parallel lineages for 110 to 150 generations produced several strains that grow robustly in glucose. We identified a 4-step bypass pathway patched together from promiscuous enzymes that restores PLP synthesis in strain JK1. None of the mutations in JK1 occurs in a gene encoding an enzyme in the new pathway. Two mutations indirectly enhance the ability of SerA (3-phosphoglycerate dehydrogenase) to perform a new function in the bypass pathway. Another disrupts a gene encoding a PLP phosphatase, thus preserving PLP levels. These results demonstrate that a functional pathway can be patched together from promiscuous enzymes in the proteome, even without mutations in the genes encoding those enzymes.

Saccharomyces cerevisiae glucose signalling regulator Mth1p regulates the organellar Na+/H+ exchanger Nhx1p

2010 ◽  
Vol 432 (2) ◽  
pp. 343-352 ◽  
Author(s):  
Keiji Mitsui ◽  
Masafumi Matsushita ◽  
Hiroshi Kanazawa
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Carbon Source ◽  
Sole Carbon Source ◽  
Glucose Sensor ◽  
Ph Regulation ◽  
Gene Knockout ◽  
Carbon Sources ◽  
Acidic Ph ◽  
In Cells

Organelle-localized NHEs (Na+/H+ exchangers) are found in cells from yeast to humans and contribute to organellar pH regulation by exporting H+ from the lumen to the cytosol coupled to an H+ gradient established by vacuolar H+-ATPase. The mechanisms underlying the regulation of organellar NHEs are largely unknown. In the present study, a yeast two-hybrid assay identified Mth1p as a new binding protein for Nhx1p, an organellar NHE in Saccharomyces cerevisiae. It was shown by an in vitro pull-down assay that Mth1p bound to the hydrophilic C-terminal half of Nhx1p, especially to the central portion of this region. Mth1p is known to bind to the cytoplasmic domain of the glucose sensor Snf3p/Rgt2p and also functions as a negative transcriptional regulator. Mth1p was expressed in cells grown in a medium containing galactose, but was lost (possibly degraded) when cells were grown in medium containing glucose as the sole carbon source. Deletion of the MTH1 gene increased cell growth compared with the wild-type when cells were grown in a medium containing galactose and with hygromycin or at an acidic pH. This resistance to hygromycin or acidic conditions was not observed for cells grown with glucose as the sole carbon source. Gene knockout of NHX1 increased the sensitivity to hygromycin and acidic pH. The increased resistance to hygromycin was reproduced by truncation of the Mth1p-binding region in Nhx1p. These results implicate Mth1p as a novel regulator of Nhx1p that responds to specific extracellular carbon sources.

scholarly journals Biodegradation of the Organic Disulfide 4,4′-Dithiodibutyric Acid by Rhodococcus spp.

2015 ◽  
Vol 81 (24) ◽  
pp. 8294-8306 ◽  
Author(s):  
Heba Khairy ◽  
Jan Hendrik Wübbeler ◽  
Alexander Steinbüchel
Keyword(s):  
Carbon Source ◽  
Sole Carbon Source ◽  
Rhodococcus Erythropolis ◽  
Model Organism ◽  
Hypothetical Protein ◽  
Gene Encoding ◽  
Content Type ◽  
Gene Coding ◽  
Initial Cleavage ◽  
Genes Encoding

ABSTRACTFourRhodococcusspp. exhibited the ability to use 4,4′-dithiodibutyric acid (DTDB) as a sole carbon source for growth. The most important step for the production of a novel polythioester (PTE) using DTDB as a precursor substrate is the initial cleavage of DTDB. Thus, identification of the enzyme responsible for this step was mandatory. BecauseRhodococcus erythropolisstrain MI2 serves as a model organism for elucidation of the biodegradation of DTDB, it was used to identify the genes encoding the enzymes involved in DTDB utilization. To identify these genes, transposon mutagenesis ofR. erythropolisMI2 was carried out using transposon pTNR-TA. Among 3,261 mutants screened, 8 showed no growth with DTDB as the sole carbon source. In five mutants, the insertion locus was mapped either within a gene coding for a polysaccharide deacetyltransferase, a putative ATPase, or an acetyl coenzyme A transferase, 1 bp upstream of a gene coding for a putative methylase, or 176 bp downstream of a gene coding for a putative kinase. In another mutant, the insertion was localized between genes encoding a putative transcriptional regulator of the TetR family (noxR) and an NADH:flavin oxidoreductase (nox). Moreover, in two other mutants, the insertion loci were mapped within a gene encoding a hypothetical protein in the vicinity ofnoxRandnox. The interruption mutant generated,R. erythropolisMI2noxΩtsr, was unable to grow with DTDB as the sole carbon source. Subsequently,noxwas overexpressed and purified, and its activity with DTDB was measured. The specific enzyme activity of Nox amounted to 1.2 ± 0.15 U/mg. Therefore, we propose that Nox is responsible for the initial cleavage of DTDB into 2 molecules of 4-mercaptobutyric acid (4MB).

L-Rhamnose metabolism in Pichia stipitis and Debaryomyces polymorphus

1994 ◽  
Vol 40 (11) ◽  
pp. 896-902 ◽  
Author(s):  
A. L. Twerdochlib ◽  
F. O. Pedrosa ◽  
S. Funayama ◽  
L. U. Rigo
Keyword(s):  
Carbon Source ◽  
Aldehyde Dehydrogenase ◽  
Enzyme Induction ◽  
Catabolite Repression ◽  
Sole Carbon Source ◽  
Pichia Stipitis ◽  
Oxidative Pathway ◽  
Debaryomyces Polymorphus

The pathway for the breakdown of L-rhamnose by the yeast Pichia stipitis NRC 5568 was shown to involve nonphosphorylated intermediates and to produce pyruvate and L-lactaldehyde. The activities of the enzymes and the nature of several intermediates were determined. The enzymes involved are L-rhamnose dehydrogenase, L-rhamnonate dehydratase, and 2-keto-3-deoxy-L-rhamnonate aldolase. This pathway was found to be inducible by L-rhamnose and repressed by D-glucose. These enzymes were also present in a mutant of P. stipitis (PR1) resistant to catabolite repression and in Debaryomyces polymorphus 1747. Cell-free extracts of P. stipitis and D. polymorphus grown in L-rhamnose as sole carbon source were found to contain NAD+-dependent aldehyde dehydrogenase activities.Key words: Pichia stipitis, enzyme induction, oxidative pathway, catabolite repression.

Cytological responses of Cladosporium resinae when shifted from glucose to hydrocarbon medium

1981 ◽  
Vol 27 (11) ◽  
pp. 1209-1218 ◽  
Author(s):  
R. A. Smucker ◽  
J. J. Cooney
Keyword(s):  
Carbon Source ◽  
Cell Walls ◽  
Sole Carbon Source ◽  
Glucose Medium ◽  
Working Model ◽  
Dense Bodies ◽  
Hydrocarbon Medium ◽  
In Cells

Cladosporium resinae was grown on glucose and then transferred to medium with glucose or with kerosene as the sole carbon source. Growth on hydrocarbon was associated with thinner cell walls in both hyphae and spores, with the presence of large vacuoles in cells, with the synthesis of microbodies, and with increased synthesis of catalase. Some vacuoles in hydrocarbon-grown cells contained small, spherical, electron-dense inclusions which were not observed in cells from glucose medium. Large, electron-dense bodies within vacuoles were observed in glucose-grown and in hydrocarbon-grown cells. A working model is proposed for oxidation of n-alkanes by C. resinae.

scholarly journals Dynamics of sodium dodecyl sulfate utilization andantibiotic susceptibility of strain Pseudomonas sp. ATCC19151

2009 ◽  
Vol 61 (2) ◽  
pp. 159-164 ◽  
Author(s):  
B. Jovcic ◽  
Jelena Begovic ◽  
Jelena Lozo ◽  
L. Topisirovic ◽  
Milan Kojic
Keyword(s):  
Carbon Source ◽  
Sodium Dodecyl Sulfate ◽  
Sole Carbon Source ◽  
Minimal Medium ◽  
Sodium Dodecyl ◽  
Pseudomonas Sp ◽  
Gene Encoding ◽  
Dodecyl Sulfate ◽  
Minimal Media ◽  
Growth Ability

Pseudomonas sp. ATCC19151 harbors a gene encoding a putative alkylsulfatase (sdsA). Here we report a growth ability of this strain in minimal media containing 0.5, 0.75, and 1% sodium dodecyl sulfate as the sole carbon source. The most prominent growth was detected for the minimal medium with 0.5% SDS, so this concentration of SDS was used to monitor Pseudomonas sp. ATCC19151 SDS biodegradation dynamics. Bacterial growth coincided with the disappearance of SDS. Antibiotic susceptibility was tested as well. Pseudomonas sp. ATCC19151 was resistant to six out of nine tested antibiotics, including ampicillin, tetracycline, chloramphenicol, tobramycin, nalidixic acid, and gentamycin.

scholarly journals Effects of Carbon Source on Expression of Fo Genes and on the Stoichiometry of the c Subunit in the F1Fo ATPase of Escherichia coli

1998 ◽  
Vol 180 (12) ◽  
pp. 3205-3208 ◽  
Author(s):  
Randy A. Schemidt ◽  
Jun Qu ◽  
James R. Williams ◽  
William S. A. Brusilow
Keyword(s):  
Escherichia Coli ◽  
Carbon Source ◽  
Proton Channel ◽  
Gene Encoding ◽  
Nonfermentable Carbon Source ◽  
C Subunit ◽  
Metabolic Conditions ◽  
A Subunit ◽  
Membrane Bound ◽  
In Cells

ABSTRACT Expression of the genes for the membrane-bound Fosector of the Escherichia coli F1Foproton-translocating ATPase can respond to changes in metabolic conditions, and these changes are reflected in alterations in the subunit stoichiometry of the oligomeric Fo proton channel. Transcriptional and translational lacZ fusions to the promoter and to two Fo genes show that, during growth on the nonfermentable carbon source succinate, transcription of the operon and translation of uncB, encoding the a subunit of Fo, are higher than during growth on glucose. In contrast, translation of the uncE gene, encoding the c subunit of Fo, is higher during growth on glucose than during growth on succinate. Translation rates of both uncB anduncE change as culture density increases, but transcription rates do not. Quantitation of the c stoichiometry shows that more c subunits are assembled into the F1Fo ATPase in cells grown on glucose than in cells grown on succinate. E. coli therefore appears to have a mechanism for regulating the composition and, presumably, the function of the ATPase in response to metabolic circumstances.

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