scholarly journals Fate of Transforming Deoxyribonucleic Acid After Uptake by Competent Bacillus subtilis: Phenotypic Characterization of Radiation-Sensitive Recombination-Deficient Mutants

1973 ◽  
Vol 114 (1) ◽  
pp. 273-286 ◽  
Author(s):  
D. Dubnau ◽  
R. Davidoff-Abelson ◽  
B. Scher ◽  
C. Cirigliano
Keyword(s):  
Bacillus Subtilis ◽  
Deoxyribonucleic Acid ◽  
Phenotypic Characterization

scholarly journals Phenotypic and Transcriptomic Characterization of Bacillus subtilis Mutants with Grossly Altered Membrane Composition

2008 ◽  
Vol 190 (23) ◽  
pp. 7797-7807 ◽  
Author(s):  
Letal I. Salzberg ◽  
John D. Helmann
Keyword(s):  
Bacillus Subtilis ◽  
Stress Responses ◽  
Membrane Lipid ◽  
Phenotypic Characterization ◽  
Peptide Antibiotic ◽  
Membrane Composition ◽  
Triple Mutant ◽  
Altered Expression ◽  
Quadruple Mutant

ABSTRACT The Bacillus subtilis membrane contains diacylglycerol-based lipids with at least five distinct headgroups that together help to define the physical and chemical properties of the lipid bilayer. Here, we describe the phenotypic characterization of mutant strains lacking one or more of the following lipids: glycolipids (ugtP mutants), phosphatidylethanolamine (pssA and psd mutants), lysylphosphatidylglycerol (mprF), and cardiolipin (ywnE and ywjE). Alterations of membrane lipid headgroup composition are generally well-tolerated by the cell, and even severe alterations lead to only modest effects on growth proficiency. Mutants with decreased levels of positively charged lipids display an increased sensitivity to cationic antimicrobial compounds, and cells lacking glycolipids are more sensitive to the peptide antibiotic sublancin and are defective in swarming motility. A quadruple mutant strain (ugtP pssA mprF ywnE), with a membrane comprised predominantly of phosphatidylglycerol, is viable and grows at near-wild-type rates, although it forms long, coiled filaments. Transcriptome comparisons identified numerous regulons with altered expression in cells of the ugtP mutant, the pssA mprF ywnE triple mutant, and the ugtP pssA mprF ywnE quadruple mutant. These effects included a general decrease in expression of the SigD and FapR regulons and increased expression of cell envelope stress responses mediated by σM and the YvrGHb two-component system.

scholarly journals Transcriptomic and Phenotypic Characterization of a Bacillus subtilis Strain without Extracytoplasmic Function σ Factors

2010 ◽  
Vol 192 (21) ◽  
pp. 5736-5745 ◽  
Author(s):  
Yun Luo ◽  
Kei Asai ◽  
Yoshito Sadaie ◽  
John D. Helmann
Keyword(s):  
Bacillus Subtilis ◽  
Cell Envelope ◽  
Dominant Role ◽  
Phenotypic Characterization ◽  
Subtilis Strain ◽  
Intrinsic Resistance ◽  
Triple Mutant ◽  
Phenotypic Differences ◽  
Σ Factor

ABSTRACT Bacillus subtilis encodes seven extracytoplasmic function (ECF) σ factors. Three (σM, σW, and σX) mediate responses to cell envelope-active antibiotics. The functions of σV, σY, σZ, and σYlaC remain largely unknown, and strong inducers of these σ factors and their regulons have yet to be defined. Here, we define transcriptomic and phenotypic differences under nonstress conditions between a strain carrying deletions in all seven ECF σ factor genes (the Δ7ECF mutant), a ΔMWX triple mutant, and the parental 168 strain. Our results identify >80 genes as at least partially dependent on ECF σ factors, and as expected, most of these are dependent on σM, σW, or σX, which are active at a significant basal level during growth. Several genes, including the eps operon encoding enzymes for exopolysaccharide (EPS) production, were decreased in expression in the Δ7ECF mutant but affected less in the ΔMWX mutant. Consistent with this observation, the Δ7ECF mutant (but not the ΔMWX mutant) showed reduced biofilm formation. Extending previous observations, we also note that the ΔMWX mutant is sensitive to a variety of antibiotics and the Δ7ECF mutant is either as sensitive as, or slightly more sensitive than, the ΔMWX strain to these stressors. These findings emphasize the overlapping nature of the seven ECF σ factor regulons in B. subtilis, confirm that three of these (σM, σW, and σX) play the dominant role in conferring intrinsic resistance to antibiotics, and provide initial insights into the roles of the remaining ECF σ factors.

scholarly journals EF-P Posttranslational Modification Has Variable Impact on Polyproline Translation in Bacillus subtilis

mBio ◽  
2018 ◽  
Vol 9 (2) ◽  
Author(s):  
Anne Witzky ◽  
Katherine R. Hummels ◽  
Rodney Tollerson ◽  
Andrei Rajkovic ◽  
Lisa A. Jones ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Posttranslational Modification ◽  
Elongation Factor ◽  
Context Dependence ◽  
Mass Spectrometry Analysis ◽  
Phenotypic Characterization ◽  
Spectrometry Analysis ◽  
High Level

ABSTRACT Elongation factor P (EF-P) is a ubiquitous translation factor that facilitates translation of polyproline motifs. In order to perform this function, EF-P generally requires posttranslational modification (PTM) on a conserved residue. Although the position of the modification is highly conserved, the structure can vary widely between organisms. In Bacillus subtilis , EF-P is modified at Lys32 with a 5-aminopentanol moiety. Here, we use a forward genetic screen to identify genes involved in 5-aminopentanolylation. Tandem mass spectrometry analysis of the PTM mutant strains indicated that ynbB , gsaB , and ymfI are required for modification and that yaaO , yfkA , and ywlG influence the level of modification. Structural analyses also showed that EF-P can retain unique intermediate modifications, suggesting that 5-aminopentanol is likely directly assembled on EF-P through a novel modification pathway. Phenotypic characterization of these PTM mutants showed that each mutant does not strictly phenocopy the efp mutant, as has previously been observed in other organisms. Rather, each mutant displays phenotypic characteristics consistent with those of either the efp mutant or wild-type B. subtilis depending on the growth condition. In vivo polyproline reporter data indicate that the observed phenotypic differences result from variation in both the severity of polyproline translation defects and altered EF-P context dependence in each mutant. Together, these findings establish a new EF-P PTM pathway and also highlight a unique relationship between EF-P modification and polyproline context dependence. IMPORTANCE Despite the high level of conservation of EF-P, the posttranslational modification pathway that activates EF-P is highly divergent between species. Here, we have identified and characterized in B. subtilis a novel posttranslational modification pathway. This pathway not only broadens the scope of potential EF-P modification strategies, but it also indicates that EF-P modifications can be assembled directly on EF-P. Furthermore, characterization of these PTM mutants has established that an altered modification state can impact both the severity of polyproline translational defects and context dependence.

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