• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.2
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• pp.136-141
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• 2005

The capability of utilizing a TCA cycle intermediates as the sole carbon source by the multi-vitamin auxotrophic yeast Torulopsis glabrata CCTCC M202019 was demonstrated with plate count method. It is indicated that T. glabrata could grew on a medium with one of the TCA cycle intermediates as the sole carbon source, but more colonies were observed when glucose, acetate and one of the TCA cycle intermediates coexisted in the medium. Among the intermediates of the TCA cycle examined in this study, cell growth was improved by supplementing oxaloacetate. Further investigation showed that the presence of acetate was necessary when oxaloacetate was supplemented. By supplementing with 10 g/L of oxaloacetate in pyruvate batch fermentation, dry cell weight increased from 11.8 g/L to 13.6 g/L, and pyruvate productivity was enhanced from $0.96\;gL^{-1}h^{-1}\;to\;1.19 gL^{-1}h^{-1}$ after cultivation of 56 h. The yield of pyruvate to glucose was also improved from 0.63 g/g to 0.66 g/g. These results indicate that under vitamins limitation, the productivity and yield of pyruvate could be enhanced via an increase of cell growth by the supplementation of oxaloacetate.

• Journal of Microbiology and Biotechnology
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• v.16 no.7
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• pp.1158-1162
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• 2006

The glyoxylate cycle can conserve carbons and adequately supply tricarboxylic acid (TCA) cycle intermediates for biosynthesis when microorganisms grow on $C_{2}$ carbon sources. It has been reported that isocitrate lyase (ICL1), a key enzyme of the glyoxylate cycle, is highly induced when Magnaporthe grisea, the causal agent of rice blast, infects its host. Therefore, the glyoxylate cycle is considered as a new target for antifungal agents. A 1.6-kb DNA fragment encoding the ICL1 from M. grisea KJ201 was amplified by PCR, cloned into a vector providing His-tag at the N-terminus, expressed in Escherichia coli, and purified using Ni-NTA affinity chromatography. The molecular mass of the purified ICL1 was approximately 60 kDa, as determined by SDS-PAGE. The ICL1 inhibitory effects of TCA cycle intermediates and their analogs were investigated. Among them, 3-nitropropionate was found to be the strongest inhibitor with an $IC_{50}$ value of $11.0{\mu}g/ml$. 3-Nitropropionate inhibited the appressorium development in M. grisea at the ${\mu}M$ level, whereas conidia germination remained unaffected. This compound also inhibited the mycelial growth of the fungus on minimal medium containing acetate as a $C_{2}$ carbon source. These results suggest that ICL1 plays a crucial role in appressorium formation of M. grisea and is a new target for the control of phytopathogenic fungal infection.

• The Microorganisms and Industry
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• v.12 no.2
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• pp.30-35
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• 1986

Almost all of the aerobic organisms contain citric acid cycle (or, tricarboxylic acid cycle). This cycle is involved both in energy metabolism and biosynthetic reactions; generation of NADH which derives the synthesis of chemical energy, ATP, and provision of intermediates needed for the biosynthesis. Because of its importance in the cellular metabolism, the regulation of the TCA cycle and its component enzymes has been extensively studied by many biologists (7,28). Citrate synthase is resposible for the initial step of the cycle and has been recognized as the rate limiting step (14,121,26). Understanding of the mechanism of the expression of citrate synthase should be a key step for the elucidation of the regulation of the TCA cycle in the cell metabolism.

• Korean Journal of Microbiology
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• v.13 no.1
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• pp.24-30
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• 1975

this work was designed to study the species belonging to Family Rhodospirillaceae in Korea. The species of Rhodopseudomonas palustris and R. gelatinosa were isolated and identified. The utilization of various substrates such as malate, succinate, citrate, pyruvate, propionate and acetate were tested with isolated KS 007 and KS o16. Though there were some differences according to nitrogen source in media it was thought that he intermediates of TCA cycle were comparatively good substrates, Also it was confirmed that isolated strains have the ability of nitrogen fixation.

• Journal of Life Science
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• v.31 no.8
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• pp.778-785
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• 2021

The germination of cucumber seeds begins with the degradation of reserved oil to fatty acids within the lipid body, which are then further metabolized to acyl-CoA. The acyl-CoA moves from the lipid body to the glyoxysome following β-oxidation for the production of acetyl-CoA. As an initial carbon source supplier, acetyl-CoA is an essential molecule in the glyoxylate cycle within the glyoxysome, which produces the metabolic intermediates of citrate and malate, among others. The glyoxylate cycle is a necessary metabolic pathway for oil seed plant germination because it produces the metabolic intermediates for the tricarboxylic acid (TCA) cycle and for gluconeogenesis, such as the oxaloacetate, which moves to the cytosol for the initiation of gluconeogenesis by phophoenolpyruvate carboxykinase (PEPCK). Following reserved oil mobilization, the production and transport of various metabolic intermediates are involved in the coordinated operation and activation of multiple metabolic pathways to supply directly usable carbohydrate in the form of glucose. Furthermore, corresponding gene expression regulation compatibly transforms the microbody to glyoxysome, which contains the organelle-specific malate synthase (MS) and isocitrate lyase (ICL) enzymes during oil seed germination. Together with glyoxylate cycle, carnitine, which mediates the supplementary route of the acetyl-CoA transport mechanism via the mitochondrial BOU (A BOUT DE SOUFFLE) system, possibly plays a secondary role in lipid metabolism for enhanced plant development.

• Journal of Microbiology and Biotechnology
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• v.6 no.2
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• pp.120-127
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• 1996

The characteristics of cell growth and poly-$\beta$-hydroxybutyrate biosynthesis of Alcaligenes latus ATCC 29713 were investigated. The PHB accumulation pattern of A. latus followed a growth-associated type where the cell growth and PHB accumulation were carried out simultaneously. Various intermediate compounds such as metabolites involved in the TCA cycle, amino acids, and saturated and unsaturated fatty acids were added to examine their effect on cell growth and PHB accumulation. Citrate, tyrosine, and palmitic acid showed the most significant increase both on cell growth and PHB accumulation. Maximum PHB concentrations were noticeably increased about 1.4 to 1.6 times higher than that of control, corresponding to 5.54, 6.45, and 6.45 g/l for citrate, tyrosine, and palmitic acid, respectively. The stimulatory effects of the supplemented metabolites were analyzed in terms of the increment of enzyme activities related to sugar catabolism and PHB biosynthesis.

• Journal of Microbiology
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• v.38 no.2
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• pp.53-61
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• 2000

Hydroxybenzoic acids are the most important intermediates in the degradative pathways of various aromatic compounds. Microorganisms catabolize aromatic compounds by converting them to hydroxylated intermediates and then cleave the benzene nucleus with ring dioxygenases. Hydroxylation of the benzene nucleus of an aromatic compound is an essential step for the initiation and subsequent disintegration of the benzene ring. The incorporation of two hydroxyl groups is essential for the labilization of the benzene nucleus. Monohydroxybenzoic acids such as 2-hydroxybenzoic acid, 3-hydroxybenzoic acid, and 4-hydrosybenzoic acid, opr pyrocattechuic acid that are susceptible for subsequent oxygenative cleavage of the benzene ring. These terminal aromatic intermediates are further degraded to cellular components through ortho-and/or meta-cleavage pathways and finally lead to the formation of constituents of the TCA cycle. Many groups of microorganisms have been isolated as degraders of hydroxybenzoic acids with diverse drgradative routes and specific enzymes involved in their metabolic pahtway. Various microorganisms carry out unusual non-oxidative decarboxylation of aromatic acids and convert them to respective phenols which have been documented. Futher, Pseudomonas and Bacillus spp. are the most ubiquitous microorganisms, being the principal components of microflora of most soil and water enviroments.

• The Microorganisms and Industry
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• v.18 no.3
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• pp.23-33
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• 1992

The general characteristics of campylobacters and related organisms (e.g., species of the genera Helicobacter and Wolinella, Bacteroides ureolyticus, and Bacteroides gracilis) are as follows: slender, non-sporeforming, gram-negative, vibroid bacteria (helical- or spiral- shpaed; except that B. ureolyticus and B. gracilis are straight-rod), 0.2-0.5 .mu.m in width and 0.5 .mu.m in length. (Smibert, 1984; Penner, 1988). The species of genus Campylobacter and related organisms are chemoorganotrophs; however, they neither oxidize nor ferment carbohydrates and instead obtain energy from amino acids, the salts of tricarboxylic acids (TCA) cycle intermediates, the salts of organic acids, or, in some species, H$\_$2/. With regard to their oxygen responses for growth, they all are microaeophilic i.e., they are capable of oxygen-dependent growth (respiring with oxygen as a terminal electron acceptor) but can not grow in the presence of a level of oxygen equivalent to that present in an air atmosphere (21% oxygen). This review will take interests in how these microorganisms response to oxygen for growth and what repiratory types they have.

• Proceedings of the Microbiological Society of Korea Conference
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• 2002.10a
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• pp.27-30
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• 2002

Ralstonia eutrupha JMP134 is a well-known soil bacterium which can metabolite diverse aromatic compounds and xenobiotics, such as phenol, 2,4-dichlorophenoxy acetic acid (2, 4-D), and trichloroethylene (TCE), etc. Phenol is degraded through chromosomally encoded phenol degradation pathway. Phenol is first metabolized into catechol by a multicomponent phenol hydroxylase, which is further metabolized to TCA cycle intermediates via a meta-cleavage pathway. The nucleotide sequences of the genes for the phenol hydroxylase have previously been determined, and found to composed of eight genes phlKLMNOPRX in an operon structure. The phlR, whose gene product is a NtrC-like transcriptional activator, was found to be located at the internal region of the structural genes, which is not the case in most bacteria where the regulatory genes lie near the structural genes. In addition to this regulatory gene, we found other regulatory genes, the phlA and phlR2, downstream of the phlX. These genes were found to be overlapped and hence likely to be co-transcribed. The protein similarity analysis has revealed that the PhlA belongs to the GntR family, which are known to be negative regulators, whereas the PhlR2 shares high homology with the NtrC-type family of transcriptional activators like the PhlR. Disruption of the phlA by insertional mutation has led to the constitutive expression of the activity of phenol hydroxylase in JMP134, indicating that PhlA is a negative regulator. Possible regulatory mechanisms of phenol metabolism in R. eutropha JMP134 has been discussed.

• Korean Journal of Microbiology
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• v.22 no.3
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• pp.135-142
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• 1984

The effect of biotin on the growth and sporulation of Bacillus subtilis SNU816 was investigated. When B. subtilis SNU816 was cultured on glucose as a sole carbon source, the growth was retarded markedly and usually ceased at early log phawe. But by addition of biotin to this medium, normal, rapid growth was restored. The growth rate was increased proportionally according to the concentration of exogenous biotin until it reached to 0.05㎍/ml, at which about three fold rapid growth was achieved. Also biotin was required for optimum sporulation for it facilitated the complete utilization of both glucose(Glc) and glutamic acid(Glu). Without biotin in Glc+Glu medium, about 40% of glutamic acid was remained unutilized. The dipicolinic acid content of cells cultured in Glc+Glu medium without biotin was markedly small and sporulation was suppressed before free spore release. Since biotin could be partiallyreplaced by one of TCA cycle intermediates such as oxalacetic acid, citric acid, or glutamic acid in enhancing growth in Glc medium, it was postulated that this strain might have a defect in converting pyruvate to oxalacetate which process is known to be mediated by pyruvate carboxylase that requires biotin as a cofactor.