The Isolation and Characterization of Alkane-oxidizing Organisms and the Effect of Growth Substrate on Isocitric Lyase

Trust, Trevor J.; Millis, Nancy F.

doi:10.1099/00221287-61-2-245

Cited by 19 publications

(9 citation statements)

References 8 publications

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“…I a), D,L-lactate or the hydrocarbon substrates resulted in high enzyme activities compared with those attained during growth on any of the other single substrates. High activities in micro-organisms growing on n-alkanes have been reported previously (Trust & Millis, 1970) and this reflects the catabolism of these compounds via acetyl-CoA. Activities during growth on I -phenylalkanes were somewhat lower than during growth on acetate, but greater than in glucose-or nutrient broth-grown organisms ( I I-and 5.5-fold increases for I-phenyldodecane-and I-phenylnonane-grown organisms, respectively).…”

Section: Effect Of Carbon Source On Growth Rate and Isocitrate Lyase supporting

confidence: 59%

Control of Isocitrate Lyase in Nocardia salmonicolor (NCIB9701)

Sariaslani¹,

Westwood²,

Higgins³

1975

Journal of General Microbiology

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Nocardia salmonicolor, grown on acetate, commercial D,L-lactate or hydrocarbon substrates, has high isocitrate lyase activities compared with those resulting from growth on other carbon sources. This presumably reflects the anaplerotic role of the glyoxylate cycle during growth on the former substrates. Amongst a variety of compounds tested, including glucose, pyruvate and tricarboxylic acid cycle intermediates, only succinate and fumarate prevented an increase in enzyme activity in the presence of acetate. When acetate (equimolar to the initial sugar concentration) was added to cultures growing on glucose, there followed de novo synthesis of isocitrate lyase and isocitrate dehydrogenase, with increases in growth rate and glucose utilization, and both acetate and glucose were metabolized simultaneously. A minute amount of acetate (40 ,LAM) caused isocitrate lyase synthesis (a three-fold increase in activity within 3 min of addition) when added to glucose-limited continuous cultures, but even large amounts added to nitrogen-limited batch cultures were ineffective. Malonate, at a concentration that was not totally growth-inhibitory (I mM) prevented the inhibition of acetate-stimulated isocitrate lyase synthesis by succinate, but fumarate still inhibited in the presence of malonate. Phosphoenolpyruvate is a noncompetitive inhibitor of the enzyme (apparent Ki 1-7 mM).The results are consistent with the induction of isocitrate lyase synthesis by acetate or a closely related metabolite, and catabolite repression by a C-4 acid of the tricarboxylic acid cycle, possibly fumarate. I N T R O D U C T I O NFor Escherichia coli, there is strong evidence that both the synthesis and activity of threo-D,-isocitrate lyase are controlled by the cytoplasmic concentration of phosphoenolpyruvate (PEP) or a closely related metabolite. PEP is a non-competitive inhibitor of the enzyme and may itself be the repressor metabolite (Kornberg, 1966). It is not surprising that PEP should have this role since it may be regarded as a major end-product of the glyoxylate cycle and the starting material for the synthesis of many compounds. Under conditions where the anaplerotic role of the glyoxylate cycle is unnecessary in this organism, such as growth on C-3, C-4 or C-6 compounds, high levels of PEP in the cytoplasm might be expected.Evidence for this control mechanism in other microbes, particularly Achromobacter sp., Acinetobacter sp. and Neurospora crassa is more equivocal. Synthesis of isocitrate lyase was not inhibited by the presence of succinate in cultures of Achromobacter d-15 growing on acetate (Rosenberger, 1962). Also, the presence of acetate in cultures growing on succinate caused enzyme synthesis. These results were quite different from those obtained with E. coli and Rosenberger interpreted them as an apparent inductive effect of acetate. However, isocitrate lyase synthesis is rapid during growth of this micro-organism on C-3 compounds

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Section: Effect Of Carbon Source On Growth Rate and Isocitrate Lyase supporting

confidence: 59%

Control of Isocitrate Lyase in Nocardia salmonicolor (NCIB9701)

Sariaslani¹,

Westwood²,

Higgins³

1975

Journal of General Microbiology

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“…Although malate synthetase activity could not be detected by the assay methods used, isocitrate lyase was induced under lipolytic conditions and the complete glyoxylate by-pass was assumed to be active (see also Trust & Millis, 1970;Hildebrandt & Weide, 1974). D. A. W. thanks the Science Research Council for a post-doctoral fellowship under grant B / R G /~~~I .9 in support of this work.…”

Section: A W H I T W O R T H a N D C R A T L E D G Ementioning

confidence: 99%

An Analysis of Intermediary Metabolism and its Control in a Fat-synthesizing Yeast (Candida 107) Growing on Glucose or Alkanes

Whitworth¹,

Ratledge²

1975

Journal of General Microbiology

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Enzymes of glycolysis, pentose phosphate pathway, gluconeogenesis, tricarboxylate acid cycle, glyoxylate by-pass and fatty-acid biosynthesis were assayed in extracts from Candida 107 grown continuously on glucose under carbon limitation, nitrogen limitation and on n-alkanes. The yeast was therefore either in a lipogenic or lipolytic state. Phosphofructokinase was absent under all conditions whereas enzymes of gluconeogenesis, including fructose I ,6-bisphosphatase and the pentose phosphate cycle, were all present. Glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase were specific for NADP+ and were inhibited in a non-competitive manner by NADPH and NADH. Phosphoenolpyruvate, citrate, ATP and acetyl CoA had no inhibitory effects. Thus glucose metabolism appears to be by the pentose phosphate pathway which will rapidly produce NADPH. This can readily be consumed during fatty-acid biosynthesis and, as there appears to be no inhibition of the flow of carbon from glucose to acetyl CoA, fatty-acid synthesis can continue for as long as there is a supply of glucose. These results help to explain the probable causes of fat build-up to high concentrations (about 40 7; of the cell dry weight) in this and other organisms. In alkane-grown cells, lipogenesis is repressed and carbon is able to flow from the alkanes via acetyl CoA, oxaloacetate and pyruvate into pentoses and hexoses in a unidirectional manner, because of the strong repression of pyruvate kinase and the increased activities of phosphoenolpyruvate kinase and fructose I ,6-bisphosphatase under these conditions. Although there was little change in the total activity of the TCA cycle enzymes under the various growth conditions, isocitrate lyase was induced under lipolytic conditions.

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“…A variety of these bacteria are involved in the degradation of alkanes (the major components of crude oils), and some strains have been characterized, including Thauera (2), Pseudomonas (3), and Geobacillus (4) strains from petroleum production wells and oil reservoirs; Burkholderia (5), Mycobacterium (6), and Acinetobacter (7) strains from petroleum-contaminated soil and streams; and Alcanivorax (8) and Rhodococcus (9) strains from an oil-polluted marine environment.…”

mentioning

confidence: 99%

Characterization of a Novel Rieske-Type Alkane Monooxygenase System in Pusillimonas sp. Strain T7-7

Wang

Feng

2013

J Bacteriol

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The cold-tolerant bacterium Pusillimonas sp. strain T7-7 is able to utilize diesel oils (C 5 to C 30 alkanes) as a sole carbon and energy source. In the present study, bioinformatics, proteomics, and real-time reverse transcriptase PCR approaches were used to identify the alkane hydroxylation system present in this bacterium. This system is composed of a Rieske-type monooxygenase, a ferredoxin, and an NADH-dependent reductase. The function of the monooxygenase, which consists of one large (46.711 kDa) and one small (15.355 kDa) subunit, was further studied using in vitro biochemical analysis and in vivo heterologous functional complementation tests. The purified large subunit of the monooxygenase was able to oxidize alkanes ranging from pentane (C 5 ) to tetracosane (C 24 ) using NADH as a cofactor, with greatest activity on the C 15 substrate. The large subunit also showed activity on several alkane derivatives, including nitromethane and methane sulfonic acid, but it did not act on any aromatic hydrocarbons. The optimal reaction condition of the large subunit is pH 7.5 at 30°C. Fe 2؉ can enhance the activity of the enzyme evidently. This is the first time that an alkane monooxygenase system belonging to the Rieske non-heme iron oxygenase family has been identified in a bacterium.

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The Isolation and Characterization of Alkane-oxidizing Organisms and the Effect of Growth Substrate on Isocitric Lyase

Cited by 19 publications

References 8 publications

Control of Isocitrate Lyase in Nocardia salmonicolor (NCIB9701)

Control of Isocitrate Lyase in Nocardia salmonicolor (NCIB9701)

An Analysis of Intermediary Metabolism and its Control in a Fat-synthesizing Yeast (Candida 107) Growing on Glucose or Alkanes

Characterization of a Novel Rieske-Type Alkane Monooxygenase System in Pusillimonas sp. Strain T7-7

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