Gene/Protein Disease Symptom Drug Enzyme Compound
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Genetic analysis of 119 acetate non-utilizing (acu) mutants in Aspergillus nidulans revealed ten new loci affecting acetate metabolism in addition to the three previously recognized on the basis of resistance to fluoroacetate and acetate non-utilization. The enzyme lesions associated with mutations at seven of the acu loci are described. These are: facA (= acuA), acetyl-CoA synthase; acuD, isocitrate lyase; acuE, malate synthase; acuF, phosphoenolpyruvate carboxykinase; acuG, fructose 1,6-diphosphatase; acuK and acuM, malic enzyme. The acu loci have been mapped and are widely distributed over the genome of A. nidulans. Close linkage has only been found between acuA and acuD (less than 1% recombination). There is no evidence for any pleiotropic mutation in that region affecting the expression of both these genes. Poor induction of the enzymes of the glyoxylate cycle, isocitrate lyase and malate synthase in mutants lacking acetyl-CoA synthase, and also in the other two classes of fluoroacetate-resistant mutants, indicates that the inducer, acetate, may be metabolized to a true metabolic inducer, perhaps acetyl-CoA, to effect formation of the enzymes. There is no evidence of any other class of pleiotropic recessive acu mutations affecting the expression of the acuD and acuE genes, which are therefore thought to be subject to negative rather than positive control.
J Gen Microbiol 1976 Feb
PMID:Analysis of acetate non-utilizing (acu) mutants in Aspergillus nidulans. 0 22

In Pseudomonas AM1, conversion of 3-hydroxybutyrate to acetyl-CoA is mediated by an inducible 3-hydroxybutyrate dehydrogenase, an acetoacetate: succinate coenzyme A transferase (specific for succinyl-CoA) and an inducible beta-ketothiolase. Ethanol is oxidized to acetate by the same enzymes as are involved in methanol oxidation to formate. An inducible acetyl-CoA synthetase has been partially purified and characterized; it is essential for growth only on ethanol, malonate and acetate plus glyoxylate, as shown by the growth characteristics of a mutant (ICT54) lacking this enzyme. Free acetate is not involved in the assimilation of acetyl-CoA, and hydroxypyruvate reductase is not involved in the oxidation of acetyl-CoA to glyoxylate during growth on 3-hydroxybutyrate. A mutant (ICT51), lacking 'malate synthase' activity has been isolated and its characteristics indicate that this activity is normally essential for growth, of Pseudomonas AM1 on ethanol, malonate and 3-hydroxybutyrate, but not for growth on other substrates such as pyruvate, succinate and C1 compounds. The growth properties of a revertant (ICT51R) and of a mutant lacking malyl-CoA lyase (PCT57) indicate that an alternative route must exist for assimilation of compounds metabolized exclusively by way of acetyl-CoA.
J Gen Microbiol 1976 Jul
PMID:Acetyl-CoA production and utilization during growth of the facultative methylotroph Pseudomonas AM1 on ethanol, malonate and 3-hydroxybutyrate. 0 84

Treatment with 60% hydrofluoric acid (HF) removed most of the phosphorus and small amounts of mannan, glucan and protein from walls of two non-flocculent strains (NCYC366 and NCYC1004) and two flocculent strains (NCYC1005 and NCYC1063) of Saccharomyces cerevisiae. Organisms of all strains showed increased flocculating ability following HF treatment. Flocculation of untreated organisms of NCYC1005 and NCYC1063, and of HF-treated organisms of all four strains, declined appreciably when they were washed in deionized water, with or without EDTA, and the flocculation was measured in deionized water instead of in 0-05 M-sodium acetate containing Ca2+. Treatment with 1,2-epoxypropane also caused a decrease in the flocculating ability of these organisms. Extracting the lipids from organisms of strains NCYC366 and NCYC1004 had no effect on their flocculating ability, but decreased the flocculating ability of organisms of strains NCYC1005 and NCYC1063. pH-electrophoretic mobility curves of untreated and HF-treated organisms confirmed the loss of wall phosphate by HF treatment, and indicated that HF treatment had little effect on the content of protein carboxyl groups in the outer wall layers. Mannose at 0-22 M completely prevented floc formation by organisms of strain NCYC1063; but, even at 0-33 M, it had very little effect on floc formation by HF-treated organisms of strains NCYC366 and NCYC1063. Organisms of all four strains bound fluorescein-conjugated concanavalin A to the same extent after treatment with HF as before, but this treatment led to a greatly diminished binding of of fluorescein-conjugated antiserum raised against organisms of strain NCYC366. The results indicate that phosphodiester linkages in yeast-wall mannan are not involved in bride formation through Ca2+ during floc formation and that this arises principally through carboxyl groups.
J Gen Microbiol 1976 Sep
PMID:Role of wall phosphomannan in flocculation of Saccharomyces cerevisiae. 1 Mar 45

Mutants of Escherichia coli K12 have been isolated that grow on media containing pyruvate of proline as sole carbon sources despite the presence of 10 or 50 mM-sodium fluoroacetate. Such mutants lack either acetate kinase [ATP: acetate phosphotransferase; EC 2.7.2.1] or phosphotransacetylase [acetyl-CoA: orthophosphate acetyltransferase; EC 2.3.1.8] activity. Unlike wild-type E. coli, phosphotransacetylase mutants do not excrete acetate when growing aerobically or anaerobically on glucose; their anaerobic growth on this sugar is slow. The genes that specify acetate kinase (ack) and phosphotransacetylase (pta) activities are cotransducible with each other and with purF and are thus located at about min 50 on the E. coli linkage map. Although Pta- and Ack- mutants are greatly impaired in their growth on acetate, they incorporate [2-14C]acetate added to cultures growing on glycerol, but not on glucose. An inducible acetyl-CoA synthetase [acetate: CoA ligase (AMP-forming); EC 6.2.1.1] effects this uptake of acetate.
J Gen Microbiol 1977 Oct
PMID:The enzymic interconversion of acetate and acetyl-coenzyme A in Escherichia coli. 2 41

The creA204, creB15 and creC27 mutations have been shown to cause carbon catabolite derepression of acetly CoA synthase and isocitrate lyase in Aspergillus nidulans. A recessive mutation, cre-34, which is linked to the creC gene, results in these enzymes being more sensitive than cre or wildtype strains to catabolite repression. The acetamidase levels of strains containing cre mutations have been investigated and provide support for the hypothesis that an acetate metabolite, rather than acetamide, induces this enzyme.
Mol Gen Genet 1977 Nov 04
PMID:Increased and decreased sensitivity to carbon catabolite repression of enzymes of acetate metabolism in mutants of Aspergillus nidulans. 2 91

The biochemical explanation for lipid accumulation was investigated principally in Candida 107 and, for comparison, in the non-oleaginous yeast Candida utilis. There were no significant differences between these two yeasts in their control of glucose uptake; in both yeasts, the rates of glucose uptake were independent of the growth rate and were higher in carbon-limited chemostat cultures than in nitrogen-limited cultures. There was no lipid turnover in either yeast, as judged from [14C]acetate uptake and subsequent loss of 14C from the lipid of steady-state chemostat cultures. Acetyl-CoA carboxylase from both yeasts was similar in most characteristics except that from Candida 107 was activated by citrate (40% activation at 1 mM). The enzyme from Candida 107 was relatively unstable and, when isolated from nitrogen-limited (lipid-accumulating) cultures, was accompanied by a low molecular weight inhibitor. The reason for lipid accumulation is attributed to the decrease in the intracellular concentration of AMP as cultures become depleted of nitrogen. As the NAD+-dependent isocitrate dehydrogenase of Candida 107, but not C. utilis, requires AMP for activity, the metabolism of citrate through the tricarboxylic acid cycle in the mitochondria becomes arrested. In Candida 107, but not in C. utilis, there is an active ATP:citrate lyase which converts the accumulating citrate, when it passes into the cytosol, into acetyl-CoA and oxaloacetate. The former product is then available for fatty acid biosynthesis which is stimulated by the high ATP concentration within the cells, by the activation of acetyl-CoA carboxylase by citrate and by the provision of NADPH generated as oxaloacetate is converted via malate to pyruvate. Similar characteristics were evident in oleaginous strains of Rhodotorula glutinis and Mucor circinelloides but not in non-oleaginous representatives of these species.
J Gen Microbiol 1979 Oct
PMID:A biochemical explanation for lipid accumulation in Candida 107 and other oleaginous micro-organisms. 4 15

The intracellular esterases of 80 strains of Proteus and Providencia were analysed by the acrylamide-agarose zymogram technique using several synthetic substrates. The esterase bands were classified in five main groups. The alphaA-esterase bands hydrolysed alpha-naphthyl acetate and were resistant or relatively insensitive to di-isofluoropropyl phosphate (DFP). The alphaB-esterase band hydrolysed both alpha-naphthyl acetate and alpha-naphthyl butyrate and were very sensitive to DFP. Both groups of esterase bands were inactivated by heat. The betaA- and betaB-esterase bands hydrolysed beta-naphthyl acetate and were sensitive to DFP; these were distinguishable by the difference in their relative activity towards beta-naphthyl butyrate and in their relative stability to heat. The alpha-beta-esterase bands hydrolysed alpha- and beta-naphthyl acetates and alpha- and beta-naphthyl butyrates; they were inactivated by heat and were sensitive to DFP. The distribution of these esterase bands among the strains of Proteus and Providencia and their electrophoretic patterns established esterase profile types which correlate with the classification based on traditional bacteriological tests. The degree of inter-strain similarity in esterase pattern varied highly among species. The homogeneity of Proteus mirabilis and especially of Providencia stuartii contrasted with the heterogeneity of other species. This disparity suggests that the bacteria of the tribe Proteae have not the same degree of intra-specific differentiation in physico-chemical properties of esterases.
J Gen Microbiol 1975 Mar
PMID:Esterase zymograms of Proteus and Providencia. 4 38

Selenomonas ruminantium produced one mole of D(-)-lactate per mole of glucose used at all dilution rates in ammonia-limited continuous culture. In contrast, lactate production varied according to the dilution rate when glucose was the limiting nutrient. At dilution rates of less than 0.2 h-1, acetate and propionate were the main fermentation products and lactate production was low. At dilution rates above 0.2 h-1, the pattern changed to one of high lactate production similar to that under ammonia limitation. Experiments with cell-free extracts of S. ruminantium showed that D(-)-lactate dehydrogenase had sigmoidal kinetics consistent with homotropic activation of the enzyme by its substrate, pyruvate. This feature allows S. ruminantium to amplify the effects of relatively small changes in the intracellular concentration of pyruvate to cause much larger changes in the rate of production of lactate. Some confirmation that this mechanism of control occurs under physiological conditions was obtained in glucose-limited culture, in which the sigmoidal increase in lactate production was accompanied by a linear increase in pyruvate excretion as the dilution rate increased.
J Gen Microbiol 1978 Jul
PMID:Control of lactate production by Selenomonas ruminantium: homotropic activation of lactate dehydrogenase by pyruvate. 10 95

Six chloroplast gene mutants of Chlamydomonas reinhardtii resistant to spectinomycin, erythromycin, or streptomycin have been assessed for antibiotic resistance of their chloroplast ribosomes. Four of these mutations clearly confer high levels of antibiotic resistance on the chloroplast ribosomes both in vivo. Although one mutant resistant to streptomycin and one resistant to spectinomycin have chloroplast ribosomes as sensitive to antibiotics as those of wild type in vivo, these mutations can be shown to alter the wildtype sensitivity of chloroplast ribosomes in polynucleotide-directed amino acid incorporation in vitro. Genetic analysis of these six chloroplast mutants and three similar mutants (Sager, 1972), two of which have been shown to affect chloroplast ribosomes (Mets and Bogorad, 1972; Schlanger and Sager, 1974), indicates that in Chlamydomonas at least three chloroplast gene loci can affect streptomycin resistance of chloroplast ribosomes and that two can affect erythromycin resistance. The three spectinomycin-resistant mutants examined appear to be alleles at a single chloroplast gene locus, but may represent mutations at two different sites within the same gene. Unlike wild type, the streptomycin and spectinomycin resistant mutants which have chloroplast ribosomes sensitive to antibiotics in vivo, grow well in the presence of antibiotic by respiring exogenously supplied acetate as a carbon source, and have normal levels of cytochrome oxidase activity and cyanide-sensitive respiration. We conclude that mitochondrial protein synthesis in these mutants is resistant to these antibiotics, whereas in wild type it is sensitive. To explain the behavior of these two chloroplast gene mutants as well as other one-step mutants which are resistant both photosynthetically and when respiring acetate in the dark, we have postulated that a mutation in a single chloroplast gene may result in alteration of both chloroplast and mitochondrial ribosomes. Mitochondrial resistance would appear to be the minimal necessary condition for survival of all such mutants, and antibiotic-resistant chloroplast ribosomes would be necessary for survival only under photosynthetic conditions.
Mol Gen Genet 1975 Oct 03
PMID:Chloroplast genes in Chlamydomonas affecting organelle ribosomes. Genetic and biochemical analysis of analysis of antibiotic-resistant mutants at several gene loci. 12 89

Inorganic sulphate (35S) was incorporated into the haemagglutinin molecule of A/Memphis/1/71 (H3N2) influenza virus when a keratosulphate-like host antigen was also incorporated into the glycoproteins of virus grown in the chorioallantoic membrane of the embryonated hen's egg. Little or no 35S-sulphate was incorporated when this hose antigen was not present in the glycoproteins of virus grown in chick embryo kidney cells or in the chorioallantoic membrane of embryonated duck eggs. The presence of the keratosulphate-like host antigen was required for the stability of the haemagglutinin molecule in sodium dodecyl sulphate (SDS). The haemagglutinin molecules from virus grown in hens' eggs were stable in SDS, whereas those from virus grown in duck eggs or in chick embryo kidney cells were not and could not be isolated on cellulose acetate. Chemical analysis showed that there were 87 glucosamine residues and three molecules of sulphate per haemagglutinin subunit as calculated for a trimer molecule having a mol. wt. of 200 000. There was one sulphate molecule per HA1 polypeptide chain and this was associated with the slowest migrating carbohydrate-protein complex of an HA1 tryptic digest separated by polyacrylamide gel electrophoresis.
J Gen Virol 1978 Nov
PMID:Host antigen as the sulphated moiety of influenza virus haemagglutinin. 15 2


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