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  • 2000-2004  (5)
  • 1975-1979  (2)
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  • 1
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Undomesticated strains of Bacillus subtilis, but not laboratory strains, exhibit robust swarming motility on solid surfaces. The failure of laboratory strains to swarm is caused by a mutation in a gene (sfp) needed for surfactin synthesis and a mutation(s) in an additional unknown gene(s). Insertional mutagenesis of the undomesticated 3610 strain with the transposon mini-Tn10 was carried out to discover genes needed for swarming but not swimming motility. Four such newly identified swarming genes are reported, three of which (swrA, swrB, and efp) had not been previously characterized and one of which (swrC) was known to play a role in resistance to the antibacterial effect of surfactin. Laboratory strains were found to harbour a frameshift mutation in the swrA gene. When corrected for the swrA mutation, as well as the mutation in sfp, laboratory strains regained the capacity to swarm and did so as robustly as the wild strain. The swrA mutation was an insertion of an A:T base pair in a homopolymeric stretch of eight A:T base pairs, and readily reverted to the wild type. These findings suggest that the swrA insertion and its reversion take place by slipped-strand mispairing during DNA replication and that swarming motility is subject to phase variation.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd.
    Molecular microbiology 43 (2002), S. 0 
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Sporulation in Bacillus subtilis involves the formation of a polar septum, which divides the sporangium into a mother cell and a forespore. The σE factor, which is encoded within the spoIIG operon, is a cell-specific regulatory protein that directs gene transcription in the mother cell. σE is synthesized as an inactive proprotein pro-σE, which is converted to the mature factor by the putative processing enzyme SpoIIGA. Processing of pro-σE does not commence until after asymmetric division when σE is largely confined to the mother cell. Processing depends on the signalling protein SpoIIR, which delays proteolysis until after polar septation, but the mechanism by which σE is confined to the mother cell is not understood. Previous work favoured a model in which pro-σE localizes to the mother cell face of the polar septum, such that σE would be selectively released into mother cell cytoplasm. Based on the use of green fluorescent protein (GFP) fusions, we now report that pro-σE is distributed approximately uniformly along all membrane surfaces and is not confined to the mother- cell face of the septum. Rather, our results are consistent with a model in which preferential and persistent transcription of the spoIIG operon in the mother cell and degradation of σE in the forespore contribute to the selective accumulation of σE in the mother cell. Persistent transcription of spoIIG after polar septation also contributes to the proper timing of pro-σE processing.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Molecular microbiology 42 (2001), S. 0 
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: We present evidence for a three-protein inhibitor of polar division that locks in asymmetry after the formation of a polar septum during sporulation in Bacillus subtilis. Asymmetric division involves the formation of cytokinetic Z-rings near both poles of the developing cell. Next, a septum is formed at one of the two polar Z-rings, thereby generating a small, forespore cell and a mother cell. Gene expression under the control of the mother-cell transcription factor σE is needed to block cytokinesis at the pole distal to the newly formed septum. We report that this block in polar cytokinesis is mediated partly by σE-directed transcription of spoIID, spoIIM and spoIIP, sporulation genes that were known to be involved in the subsequent process of forespore engulfment. We find that a spoIID, spoIIM and spoIIP triple mutant substantially mimicked the bipolar division phenotype of a σE mutant and that cells engineered to produce SpoIID, SpoIIM and SpoIIP prematurely were inhibited in septum formation at both poles. Consistent with the hypothesis that SpoIID, SpoIIM and SpoIIP function at both poles of the sporangium, a GFP–SpoIIM fusion localized to the membrane that surrounds the engulfed forespore and to the potential division site at the distal pole.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Molecular microbiology 49 (2003), S. 0 
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Swarming motility was identified and characterized in an undomesticated strain of Bacillus subtilis. Rapid surface migration was preceded by a cell density-dependent lag period, which could be eliminated if actively swarming cells were used as the inoculum. The leading edge of the swarm was characterized by multicellular rafts of highly flagellated cells. Flagellum biosynthesis and surfactant production were required for swarming. Swarming was not found in any of several standard laboratory strains. Laboratory strains are characteristically unable to produce surfactant, but such a strain remained unable to swarm even when surfactant was provided by extracellular complementation. We conclude that robust swarming is a feature of undomesticated B. subtilis and that this behaviour has been lost or attenuated in laboratory strains through the accumulation of multiple genetic defects.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Molecular microbiology 50 (2003), S. 0 
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: The master regulator for entry into sporulation in Bacillus subtilis is the DNA-binding protein Spo0A, which has been found to influence, directly or indirectly, the expression of over 500 genes during the early stages of development. To search on a genome-wide basis for genes under the direct control of Spo0A, we used chromatin immunoprecipitation in combination with gene microarray analysis to identify regions of the chromosome at which an activated form of Spo0A binds in vivo. This information in combination with transcriptional profiling using gene microarrays, gel electrophoretic mobility shift assays, using the DNA-binding domain of Spo0A, and bioinformatics enabled us to assign 103 genes to the Spo0A regulon in addition to 18 previously known members. Thus, in total, 121 genes, which are organized as 30 single-gene units and 24 operons, are likely to be under the direct control of Spo0A. Forty of these genes are under the positive control of Spo0A, and 81 are under its negative control. Among newly identified members of the regulon with transcription that was stimulated by Spo0A are genes for metabolic enzymes and genes for efflux pumps. Among  members  with  transcription  that  was in-hibited by Spo0A are genes encoding components of the DNA replication machinery and genes that govern flagellum biosynthesis and chemotaxis. Also in-cluded in the regulon are many (25) genes with products that are direct or indirect regulators of gene transcription. Spo0A is a master regulator for sporulation, but many of its effects on the global pattern of gene transcription are likely to be mediated indirectly by regulatory genes under its control.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 282 (1979), S. 256-260 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] A modified form of RNA polymerase from Bacillus subtilis selectively transcribes a cloned gene under early sporulation control. This RNA polymerase lacks σ factor but contains a newly identified subunit of molecular weight 37,000, termed P37. P37 could be a ...
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 257 (1975), S. 248-251 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Fig. 1 SDS polyacrylamide slab gel electrophoresis of enzyme B, enzyme C, 8 and a. Enzymes B and C were purified as described previously6. 5 and a were dissociated from purified holoenzyme9 from uninfected B. subtilis by chromatography on phosphocellu-lose9, dialysed agamst buffer C (ref. 4) ...
    Type of Medium: Electronic Resource
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