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1.
About 80% of Bacillus subtilis cells form spores when grown in nutrient broth. In medium containing various short-chain aliphatic alcohols, the frequency of sporulation was reduced to 0.5%. Mutants sporulated in the presence of alcohols at a frequency of 30 to 40%. Sporulation in the wild-type cells was sensitive to alcohol at the beginning of sporulation (stage zero). Sensitivity to alcohol in the mutants was also at stage zero, even though the sensitivity was considerably reduced. This sensitivity of sporulation to alcohol is the phenotypic expression of a genetic locus designated ssa. Mutations at this locus lead to a decreased sensitivity of sporulation to alcohol without modifying the sensitivity of growth. Genetic analysis by transduction was bacteriophage PBS1 revealed that ssa mutations are near the previously described spo0A locus. ssa mutants also differ from wild-type cells in the composition of membrane phospholipids. The relative amount of phosphatidylglycerol increased, whereas the relative amount of phosphatidylethanolamine and lysylphosphatidylglycerol decreased relative to the proportions in the wild type. The distribution of fatty acids in membrane lipids is the same as in the wild type. No differential sensitivity of phospholipid metabolism to alcohol could be detected in the mutant. This work therefore reveals that the extensive, pleiotropic changes in the membranes of ssa mutants are the phenotypic reflection of alterations at a specific gene locus. 相似文献
2.
In decadent sporulation mutants, sporulating populations are heterogeneous: the cells reach successive chemical and physical resistances with progressively decreasing frequencies. Each decadent mutant can be characterized by the shape and slope of the curve describing the frequency of cells resistant to various agents ('the resistance spectrum'). In some mutants the resistance spectrum decreases progressively from xylene resistance to heat resistance; in other mutants it decreases rapidly between octanol resistance and chloroform resistance. Electron microscopy showed that in two mutants the majority of the cells are blocked at stages III and IV; the number of cells that develop further to reach successive morphological stages falls off progressively. In two other mutants most cells reach stage V. Cortexless spores are also frequent. One of the decadent mutations, SpoL1, was localized between aroD and acf. The phenotype of decadent mutants is discussed in terms of sequential gene activation. 相似文献
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Phenotypes of pleiotropic-negative sporulation mutants of Bacillus subtilis 总被引:18,自引:13,他引:5 下载免费PDF全文
The phenotypic properties of representatives of the five genetic classes of pleiotropic-negative sporulation mutants have been investigated. Protease production, alkaline and neutral proteases, was curtailed in spoA mutants, but the remainder of mutant classes produced both proteases, albeit at reduced levels. The spoA and spoB mutants plaqued phi2 and phi15 at high efficiency, but the efficiency of plating of these phages on spoE, spoF, and spoH mutants was drastically reduced. Antibiotic was produced by the spoH mutants and to a degree by some spoF mutants, but the other classes did not produce detectable activity. The spoA mutants were less responsive to catabolite repression of histidase synthesis by glucose than was the wild type. Severe catabolite repression could be induced in spoA mutants by amino acid limitation, suggesting that the relaxation of catabolite repression observed is not due to a defect in the mechanism of catabolite repression. Although others have shown a perturbation in cytochrome regulation in spoA and spoB mutants, the primary dehydrogenases, succinate dehydrogenase and reduced nicotinamide adenine dinucleotide dehydrogenase, leading to these cytochromes are unimpaired in all mutant classes. A comparison of the structural components of cell walls and membranes of spoA and the wild type is made. The pleiotropic phenotypes of these mutants are discussed. 相似文献
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Among spontaneously occurring antibiotic-resistant mutants of Bacillus subtilis 168 we have identified a sub-class that is conditionally sporulative. Mutants in this sub-class are resistant to antibiotic during vegetative growth but are sensitive during sporulation. Mutants conditionally-resistant to erythromycin, kanamycin, spectinomycin, and streptomycin have been isolated and characterized by phase contrast microscopy and with respect to their ability to synthesize heat-resistant endospores or the sporulation-associated enzyme alkaline phosphatase. The results suggest that several entirely different genetic lesions may result in this single phenotype. This group includes mutants whose properties suggest that both th 30S and 50S ribosomal subunits may be altered concomitant with early spore specific metabolism. The blockage imposed by antibiotic may be at or near Stage 2 of sporulation. 相似文献
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Mary Bownes Nicole Bournias-Vardiabasis Wendy J. Spare 《Molecular & general genetics : MGG》1979,174(1):67-74
Summary Eight alleles of spineless-aristapedia (ss
a
) were analysed for penetrance and expressivity at 18° C and 25° C. All alleles are recessive and none exhibits a maternal effect. Both ss
a40a
and ss
aB
are temperature sensitive with a higher penetrance at 18° C than 25° C. ss
aUCI
, ss
ak
, ss
a
, ss
ax
and ss
a
are viable alleles with variable penetrance and expressivity whereas ss
aCam
is a lethal allele. All mutants were tested as hemizygotes using the Df(3R) bxd
100 deletion. The viable alleles showed a more extreme penetrance and expressivity when hemizygous, several becoming lethal near eclosion. Each of the eight alleles was examined in heterozygous combinations with each of the others. The lethal allele ss
aCam
was viable in combination with all other alleles. The temperature sensitivity (t.s.) of ss
aB
and ss
a40a
when heterozygous with the non-t.s. alleles was variable; some combinations were t.s. with respect to penetrance and others with respect to expressivity, whilst some heterozygotes completely lost their sensitivity to temperature.It seems, therefore, that various aspects of the spineless-aristapedia phenotype, such as the temperature sensitivity, can be separated from the expressivity and penetrance in certain allelic combinations. This suggests a very complex gene function which is, however, experimentally separable into its components. 相似文献
10.
Use of temperature-sensitive mutants to study gene expression during sporulation in Bacillus subtilis. 总被引:14,自引:10,他引:4 下载免费PDF全文
M Young 《Journal of bacteriology》1976,126(2):928-936
11.
Analysis of temperature-sensitive sporulation mutants of Bacillus subtilis by transduction 总被引:1,自引:0,他引:1
M Rogolsky 《Canadian journal of microbiology》1972,18(5):689-691
12.
B Kunkel 《Trends in genetics : TIG》1991,7(5):167-172
13.
Mutations in the spoIIIA and spoIIIJ loci disrupt the compartmentalization of gene expression during sporulation of Bacillus subtilis. The breakdown in compartmentalization is not the cause of their being blocked in spore formation. Rather, it appears to be a consequence of the engulfed prespore's being unstable. 相似文献
14.
G Balassa 《Biochemical and biophysical research communications》1964,15(3):240-242
15.
Summary Specitinomycin-resistant mutants of Bacillus subtilis show three different types of alterations in sporulation ability. Class 1 mutants can both grow and sporulate in the presence of spectinomycin. Class 2 mutants can grow in the presence of spectinomycin, but are unable to sporulate in either the presence or absence of spectinomycin. Class 3 mutants have a conditional phenotype, and are able to sporulate in the absence of spectinomycin, but not in its presence. The ability of these strains to produce alkaline phosphatase, a biochemical marker for early sporulation events, is correlated with the ability to sporulate in the presence or absence of antibiotic. All of the spectinomycin-resistance mutations could be genetically linked to the cysA marker, and a mutational alteration of a protein of the 30S ribosomal subunit has been identified in one of the Class 3 strains (Spc1–11). Fine-structure mapping of the spectinomycin resistance mutation of strain Spc 1–11 confirmed its location in the cluster of genes for ribosomal components on the B. subtilis genetic map. Genetic analysis indicated that the properties of the Class 1 and Class 2 mutants result from more than one mutation. The spectinomycin-resistance and altered sporulation properties of the two Class 3 mutants probably result from a single genetic lesion. 相似文献
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H Takagi A Suzumura T Hoshino S Nakamori 《Journal of industrial microbiology & biotechnology》1999,23(3):214-217
The Bacillus subtilis subtilisin E gene was cloned into an expression vector of the extreme thermophile, Thermus thermophilus. Active subtilisin E was produced in E. coli, indicating that the Thermus promoter functions in E. coli. When the plasmid was further introduced into T. thermophilus, the subtilisin E gene was expressed and the gene product accumulated as an inactive pro-form, because the autoprocessing
of the wild-type enzyme to the active-form did not occur at 50°C or above.
Received 17 March 1999/ Accepted in revised form 28 June 1999 相似文献
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19.
Production of adenosine triphosphate in normal cells and sporulation mutants of Bacillus subtilis 总被引:26,自引:0,他引:26
W Klofat G Picciolo E W Chappelle E Freese 《The Journal of biological chemistry》1969,244(12):3270-3276
20.
The regulation of aconitase and isocitrate dehydrogenase in sporulation mutants of Bacillus subtilis 总被引:16,自引:0,他引:16
P Fortnagel 《Biochimica et biophysica acta》1970,222(2):290-298