共查询到20条相似文献,搜索用时 500 毫秒
1.
Kerstin Holm Eva Nilheden H. Gunnar Kølmark Kenneth Burton 《Molecular & general genetics : MGG》1976,144(1):11-15
Summary Genetic analysis showed that the glycerol non-utilizing isolate gly-u(234) of Neurospora crassa is derived by mutation in a nuclear gene situated in the right arm of linkage group I, about 2.2 crossover units distal to ad-9 and 11 units proximal to nit-1.Enzymatic testings using a radiochemical method indicate that the mutant is deficient for the enzyme glycerol kinase. The radiochemical testings further indicate that the mutation has inactivated an inducible glycerol kinase, while a low residual activity may be due to a second, basal and non-inducible glycerol kinase, in accordance with a proposal by North (1973, 1974) that Neurospora has two glycerol kinases with these properties. 相似文献
2.
Glycerol uptake, glycerol kinase (EC 2.7.1.30) and glycerol-3-phosphate dehydrogenase (EC 1.1.99.5) activities are specifically induced during growth ofPseudomonas aeruginosa PAO on either glycerol or glycerol-3-phosphate. Mutants of strain PAO unable to grow on both glycerol and glycerol-3-phosphate were isolated. Mutant PFB 121 was deficient in an inducible, membrane-bound, pyridine nucleotide-independent, glycerol-3-phosphate dehydrogenase activity and PFB 82 was deficient in glycerol uptake and glycerol kinase and glycerol-3-phosphate dehydrogenase activities. Each mutant spontaneously reverted to wild phenotype, which indicates that each contained a single genetic lesion. These results demonstrate that membrane-bound, inducible glycerol-3-phosphate dehydrogenase is required for catabolism of both glycerol and glycerol-3-phosphate and provide suggestive evidence for a single regulatory locus that controls the synthesis of glycerol uptake, glycerol kinase, and glycerol-3-phosphate dehydrogenase inP. aeruginosa. 相似文献
3.
Mutants of Schizosaccharomyces pombe unable to grow or growing very slowly on glycerol have been isolated. Some, which could grow on dihydroxyacetone, lacked, or in one mutant possessed reduced amounts of, glycerol dehydrogenase (glycerol:NAD+ 2-oxidoreductase); others could not grow on dihydroxyacetone and lacked dihydroxyacetone kinase. Spontaneous revertants able to grow on glycerol had regained these enzymes. These results provide evidence that glycerol catabolism in S. pombe proceeds via initial dehydrogenation of glycerol followed by phosphorylation of dihydroxyacetone. There is evidence that dihydroxyacetone can be converted to a toxic product. 相似文献
4.
New mutant alleles of theadenosine2 locus (ade2; 2–17.7) have been isolated using the eye-color phenotype exhibited by the prototype auxotrophic alleleade2
1 as the screening criterion. The new mutants form a single complementation group, suggesting that they all exhibit purine auxotrophy and defective formylglycineamide ribotide amidotransferase enzyme, likeade2
1. Tests carried out on particular new alleles confirm these suggestions. The new mutants all exhibit more extreme physical defects than the prototype. They have wing abnormalities like mutants defective in pyrimidine biosynthesis and reduced bristles like those defective in protein synthesis; thus they exhibit the combined visible phenotype ofrudimentary wings,rosy eyes, andbobbed bristles. Cytogenetic analysis places the locus in the interband proximal to26B1-2.This work was supported by NSERC Operating Grant A3269 to D.N., an Alberta Heritage Foundation for Medical Research Postdoctoral Fellowship to S.Y.K.T., and National Institute on Aging Grant AG00029 to D.P. 相似文献
5.
A perithecial color mutant of Neurospora crassa 总被引:5,自引:0,他引:5
Summary A mutation, per-1, was found in N. crassa which caused orange instead of black perithecia when the protoperithecial parent contained the per-1 allele. No effect of per-1 was found on vegetative morphology or nutritional requirements. The per-1 locus was mapped proximal to iv (?6201) in the right arm of linkage group V. 相似文献
6.
Aureobasidium pullulans produced extracellularly considerable amounts of polyols in the media with sucrose, glucose, fructose and mannose as sole carbon source during the late exponential and stationary phase of growth. The maximum yield of polyol was about 23% in the 20%(w/v) sucrose medium, of which mannitol was the main polyol associated with minute quantities of glycerol. Stress solutes such as NaCl and KCl did not promote polyol production. 相似文献
7.
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. 相似文献
8.
High-resolution preparative gel electrophoresis: separation and recovery of functional messenger RNA species 总被引:2,自引:0,他引:2
Certain open-chain polyols were shown to interfere with the determination of phosphorus of the Lowry-Lopez method by forming a complex with Mo7O246?. The ability to interfere with the assay increased with increasing chain length of the polyols: Ethylene glycol and glycerol did not react at all; i-erythritol reacted to a small extent, but hexitols and perseitol formed stronger complexes. Depending on the polyol, interference occurred even at 0.2 mm (hexitols) or 2 mm (xylitol) concentrations. At these concentrations the polyols interfered only to a small extent with the phosphorus assays based on the use of Triton X-100 and molybdate. The complex formation was exploited in the development of a colorimetric polyol assay. 相似文献
9.
Effect of Intracytoplasmic Membrane Development on Oxidation of Sorbitol and Other Polyols by Gluconobacter oxydans 总被引:1,自引:0,他引:1
下载免费PDF全文
![点击此处可从《Journal of bacteriology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
By using membrane-bound dehydrogenases, Gluconobacter oxydans characteristically accomplishes single-step oxidation of many polyols and quantitative release of the oxidation product into the medium. These cells typically differentiate by forming intracytoplasmic membranes (ICM) after exponential growth on glycerol. Earlier experiments demonstrated that glycerol-grown cells containing ICM oxidized glycerol more rapidly than cells which were harvested during exponential growth and lacked ICM (Claus et al., J. Bacteriol. 123:1169-1183). This report demonstrates that ICM are also formed after growth on sorbitol. Sorbitol-grown, ICM-containing maximum stationary-phase (MSP) cells showed from 50 to 300% greater oxidation (respiration) rates on mannitol, glycerol, glucose, meso-erythritol, and meso-inositol than did exponential-phase (EXP) cells which lacked ICM. Both EXP and MSP cells exhibited maximum sorbitol oxidation at pH 5.0, 38°C, and 5% (wt/vol) sorbitol. When assayed under these optimum conditions, ICM-containing MSP cells demonstrated a 72% increase in respiration on sorbitol compared with that of EXP cells lacking ICM (oxygen quotients of 3,100 and 1,800, respectively). Gas chromatographic studies showed that sorbose was the only detectable product released from cells during oxygen quotient analysis. The specific activity of particulate-bound sorbitol dehydrogenase from ICM-containing MSP cells was twice that obtained from particulate fractions prepared from EXP cells lacking ICM. These results show that neither ICM formation after exponential growth nor increased respiration of other polyols is dependent upon the polyol used to grow cells. Our results suggest that increased respiratory activity of MSP cells is caused both by ICM formation and by increased synthesis (or activity) of the polyol dehydrogenases found in these membranes. 相似文献
10.
Isao Katsura 《Molecular & general genetics : MGG》1976,148(1):31-42
Summary Mutants of coliphage lambda defective in structural genes were isolated and characterized. The isolation method consisted in lysogenizing bacteria with mutagenized phage and testing for inability to form plaques after heat induction. The mutants were propagated as prophages in the lysogens. Mutants in the region of the tail-genes U, V. G and H were enriched for by a selection method based on recombination and complementation with known mutants, and they were mapped by deletion mapping with newly isolated dg's. The lysates of all the mutants were examined by electron microscopy. Some of the mutants showed phenotypes different from those of known amber mutants in the same genes. They are interpreted as producing partially active, altered gene products and might be useful for the studies of morphogenesis and of the mechanism of infection. 相似文献
11.
Isolation and characterization of mutants from Schyzosaccharomyces pombe defective in glycerol catabolism 总被引:1,自引:0,他引:1
Mutants unable to grow on glycerol were isolated from the fission yeast Schyzosaccharomyces pombe. Two types of mutants were obtained: one type was able to grow on dihydroxyacetone while the other one did not grow on this compound. The first type of mutants was defective in glycerol dehydrogenase while the second one was affected both in the glycerol dehydrogenase and in dihydroxyacetone kinase. It was found that the second type was defective in the derepression of several enzymes. The mutations were nuclear and monogenic and defined two complementation groups. Spontaneous revertants, able to grow on glycerol, were obtained from the first type of mutants. They have regained the glycerol dehydrogenase activity. The results presented provide genetic evidence for a pathway of glycerol catabolism in Sch. pombe involving dehydrogenation of glycerol as the first step followed by phosphorylation of the dihydroxyacetone formed. 相似文献
12.
Genetic analysis of carbohydrate transport-deficient mutants of Salmonella typhimurium 总被引:4,自引:1,他引:3
下载免费PDF全文
![点击此处可从《Journal of bacteriology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Mutants (car) isolated from Salmonella typhimurium were unable to utilize or ferment the following carbohydrates (all d-configuration): glucose, fructose, mannose, N-acetylglucosamine, sorbitol, mannitol, maltose, melibiose, and glycerol. The mutants did utilize galactose, glucose 6-phosphate, gluconic acid, glucuronic acid, pyruvate, and l-lactate. Biochemical analysis showed that there were two classes of mutants, each lacking one component of a phosphotransferase system. CarA mutants were deficient in enzyme I; carB lacked the phosphate carrier protein, HPr. Mapping experiments showed that the carA gene was located near pro; the carB gene mapped near purC. 相似文献
13.
Summary The yeastZygosaccharomyces rouxii ATCC 12572 was selected for its ability to produce appreciable levels of ethanol and of various polyols from concentrated glucose media (20 %, w/v).Z. rouxii was shown to yield large quantities of glycerol and of the mixture arabitol + mannitol. Good agitation combined with appropriate aeration (1 vvm) allowedZ. rouxii to utilize glucose readily leading to high polyol production. Depending on the fermentation conditions used,Z. rouxii ATCC 12572 will give either ethanol or various polyols as main fermentation product(s). 相似文献
14.
The genetic analysis of regulation of amidase synthesis in Aspergillus nidulans. I. Mutants able to utilize acrylamide 总被引:17,自引:0,他引:17
Summary
Aspergillus nidulans uses an acetamidase enzyme to grow on acetamide as a carbon or as a nitrogen source. Acrylamide is a substrate for the enzyme
but does not induce its synthesis. Mutants capable of growing on acrylamide as a nitrogen source have been isolated. Two classes
of mutant have been found —amdR
c mutants on linkage group II andamdT
c on linkage group III.amdR
c mutants produce high constitutive acetamidase levels. The enzyme is still inducible by amides, but to a lesser extent than
wild type, and is still subject to repression by ammonia and by carbon metabolites derived from glucose.amdR
c mutants are semi-dominant to the wild type allele in heterozygous, diploids. TheamdT
c mutant is not subject to carbon metabolite repression, of the acetamidase. The enzyme is inducible by amides and repressible
by ammonia. TheamdT
c mutation also results in reduced ability to grow on formamide as a nitrogen source and to lowered levels of a second amidase
enzyme.amdT
c is semi-dominant in heterozygous diploids. 相似文献
15.
I. Esteves B. Peteira S. Powers N. Magan B.R. Kerry 《Biocontrol Science and Technology》2009,19(2):185-199
For the first time, the effects of varying osmotic and matric potential on fungal radial growth and accumulation of polyols were studied in three isolates of Pochonia chlamydosporia. Fungal radial growth was measured on potato dextrose agar modified osmotically using potassium chloride or glycerol. PEG 8000 was used to modify matric potential. When plotted, the radii of the colonies were found to grow linearly with time, and regression was applied to estimate the radial growth rate (mm day?1). Samples of fresh mycelia from 25-day-old cultures were collected and the quantity (mg g?1 fresh biomass) of four polyols (glycerol, erythritol, arabitol and mannitol) and one sugar (glucose) was determined using HPLC. Results revealed that fungal radial growth rates decreased with increased osmotic or matric stress. Statistically significant differences in radial growth were found between isolates in response to matric stress (P<0.006) but not in response to osmotic stress (P=0.759). Similarly, differences in the total amounts of polyols accumulated by the fungus were found between isolates in response to matric stress (P<0.001), but not in response to osmotic stress (P=0.952). Under water stress, the fungus accumulated a combination of different polyols important in osmoregulation, which depended on the solute used to generate the stress. Arabitol and glycerol were the main polyols accumulated in osmotically modified media, whereas erythritol was the main polyol that was accumulated in media amended with PEG. The results found that Pochonia chlamydosporia may use different osmoregulation mechanisms to overcome osmotic and matric stresses. 相似文献
16.
Summary Mutation studies were carried out onAspergillus terreus ATCC 52430 to increase cellulase production. Optimal treatment conditions for increasing cellulase activity by UV mutagenesis
were observed by exposure of spores to a UV germicidal lamp, wavelength 250 nm at a distance of 30 cm for 1 min. Nitrosoguanidine
mutagenesis was optimal with respect to development of high cellulase mutants when spores were exposed to 500 ug/ml nitrosoguanidine
for 1 h. Mutants were isolated on agar containing Walseth cellulose and the catabolite repressor, glycerol. Successive UV
and nitrosoguanidine treatments resulted in isolation of strain UNG1-40 having 3.5, 4.6 and 3.3-fold increases in filter paper,
β-glucosidase and carboxymethyl cellulase activity, respectively, compared toA. terreus ATCC 52430. 相似文献
17.
Petrus Jakobus van Zyl Bernard Alexander Prior 《Applied microbiology and biotechnology》1990,33(1):12-17
Summary Glycerol and arabitol were the main polyols accumulated by Zygosaccharomyces rouxii in continuous culture but the intracellular and extracellular concentrations of the polyols varied with the dilution rate and osmoticum used to adjust the water activity (aw) to 0.960. When the aw was adjusted with NaCl, glycerol was the main polyol accumulated intracellularly whereas glycerol and arabitol were accumulated when polyethylene glycol (PEG) 400 was used. The extracellular glycerol and arabitol concentrations at 0.960 aw (NaCl or PEG 400) were similar or decreased relative to cultures at 0.998 aw. Compared to steady-state cultivation at 0.998 aw, the yeast retained at 0.960 aw (NaCl or PEG 400) a greater proportion of the total glycerol intracellularly against an increased concentration ratio without significantly greater production of glycerol. Arabitol was only significant in osmoregulation when cultivated at 0.960 aw (PEG 400). The intracellular glycerol concentration was insufficient to balance the aw across the membrane, but an equilibrium could be achieved under certain conditions if arabitol was also osmotically active.
Offprint requests to: P. J. van Zyl 相似文献
18.
Na+, K+ and the ratio of Na+/K+ were higher in cells of the halotolerant Aspergillus repens grown with 2 M NaCl than without NaCl. The osmolytes, proline, glycerol, betaine and glutamate, did not affect the Na+/K+ ratio, nor the polyol content of cells under any conditions. The concentrations of polyols, consisting of glycerol, arabitol, erythritol and mannitol, changed markedly during growth, indicating that they have a crucial role in osmotic adaptation. 相似文献
19.
Relationship between the photoproduction of hydrogen and the accumulation of PHB in non-sulphur purple bacteria 总被引:7,自引:0,他引:7
Eilert Hustede Alexander Steinbüchel Hans G. Schlegel 《Applied microbiology and biotechnology》1993,39(1):87-93
Wild type cells of Rhodobacter sphaeroides and Rhodospirillum rubrum strains Ha and S1 as well as mutant cells defective in the synthesis of poly-(3-Hydroxybutyric acid) (PHB), were used to study the competition between PHB accumulation and photoproduction of hydrogen for reducing equivalents. Mutants were isolated after transposon (Tn5) or N-methyl-N-nitro-N-nitrosoguanidine mutagenesis. The PHB-defective mutants of R. sphaeroides lacked PHB synthase activity. In two mutants Tn5 was inserted in the PHB synthase gene. No mutants occured that lacked the activity of -ketothiolase or acetoacetyl-coenzyme A reductase. Pronounced competitive effects occured only with acetate as the organic substrate. With other organic acids or sugars, which are less readily converted to PHB than acetate, competitive effects were not significant or absent.
Correspondence to: H. G. Schlegel 相似文献
20.
A new dispensable genetic locus of the terminus region involved in control of cell division in Escherichia coli 总被引:4,自引:0,他引:4
Summary Temperature-sensitive mutants defective in cell division were isolated after localised mutagenesis of the terminus region of the Escherichia coli chromosome. The defective gene in one of these mutants, dicA, was mapped at 34.9 min by linkage with manA and with three physically characterized Tn10 insertions. Temperature-sensitivity conferred by mutation dicA1 in a recA backround was suppressed by the presence of hybrid plasmids carrying the wild-type gene. In addition, the mutation was suppressed either by tranposon inactivation of a nearby gene, dicB, or by deletion of the entire dicA-dicB interval. These results define the dicA-dicB locus as a new dispensable genetic cluster involved in the control of cell division. 相似文献