scholarly journals Genetic Requirements for Potassium Ion-Dependent Colony Spreading in Bacillus subtilis

2005 ◽  
Vol 187 (24) ◽  
pp. 8462-8469 ◽  
Author(s):  
Rebecca F. Kinsinger ◽  
Daniel B. Kearns ◽  
Marina Hale ◽  
Ray Fall
Keyword(s):  
Bacillus Subtilis ◽  
Ph Control ◽  
Growth Conditions ◽  
Gene Replacement ◽  
Potassium Ion ◽  
Nucleotide Biosynthesis ◽  
Surface Colonization ◽  
Transposon Insertion ◽  
Colony Spreading ◽  
Sliding Motility

ABSTRACT Undomesticated strains of Bacillus subtilis exhibit extensive colony spreading on certain soft agarose media: first the formation of dendritic clusters of cells, followed by spreading (pellicle-like) growth to cover the entire surface. These phases of colonization are dependent on the level of potassium ion (K+) but independent of flagella, as verified with a mutant with a hag gene replacement; this latter finding highlights the importance of sliding motility in colony spreading. Exploring the K+ requirement, directed mutagenesis of the higher-affinity K+ transporter KtrAB, but not the lower-affinity transporter KtrCD, was found to inhibit surface colonization unless sufficient KCl was added. To identify other genes involved in K+-dependent colony spreading, transposon insertion mutants in wild-type strain 3610 were screened. Disruption of genes for pyrimidine (pyrB) or purine (purD, purF, purH, purL, purM) biosynthetic pathways abolished the K+-dependent spreading phase. Consistent with a requirement for functional nucleic acid biosynthesis, disruption of purine synthesis with the folic acid antagonist sulfamethoxazole also inhibited spreading. Other transposon insertions disrupted acetoin biosynthesis (the alsS gene), acidifying the growth medium, glutamine synthetase (the glnA gene), and two surfactin biosynthetic genes (srfAA, srfAB). This work identified four classes of surface colonization mutants with defective (i) potassium transport, (ii) surfactin formation, (iii) growth rate or yield, or (iv) pH control. Overall, the ability of B. subtilis to colonize surfaces by spreading is highly dependent on balanced nucleotide biosynthesis and nutrient assimilation, which require sufficient K+ ions, as well as growth conditions that promote sliding motility.

scholarly journals CcpB, a Novel Transcription Factor Implicated in Catabolite Repression in Bacillus subtilis

1998 ◽  
Vol 180 (3) ◽  
pp. 491-497 ◽  
Author(s):  
Sylvie Chauvaux ◽  
Ian T. Paulsen ◽  
Milton H. Saier
Keyword(s):  
Transcription Factor ◽  
Bacillus Subtilis ◽  
Catabolite Repression ◽  
Dna Binding Protein ◽  
Growth Conditions ◽  
Liquid Media ◽  
Phosphotransferase System ◽  
Partial Loss ◽  
Transposon Insertion ◽  
Solid Media

ABSTRACT Recent work has shown that in Bacillus subtiliscatabolite repression of several operons is mediated by a mechanism dependent on DNA-binding protein CcpA complexed to a seryl-phosphorylated derivative of HPr [HPr(Ser-P)], the small phosphocarrier protein of the phosphoenolpyruvate-sugar phosphotransferase system. In this study, it was found that a transposon insertional mutation resulted in the partial loss of gluconate (gnt) and xylose (xyl) operon catabolite repression by glucose, mannitol, and sucrose. The transposon insertion was localized to a gene, designated ccpB, encoding a protein 30% identical to CcpA, and relief from catabolite repression was shown to be due to the absence of CcpB rather than to the absence of a protein encoded by a downstream gene within the same operon. The relative intensities of CcpA- and CcpB-mediated catabolite repression depended on growth conditions. On solid media, and when cells were grown in liquid media with little agitation, CcpB and CcpA both proved to function in catabolite repression. However, when cells were grown in liquid media with much agitation, CcpA alone mediated catabolite repression. Like CcpA, CcpB appears to exert its catabolite-repressing effect by a mechanism dependent on the presence of HPr(Ser-P).

scholarly journals Autoinduction of Bacillus subtilis phoPR Operon Transcription Results from Enhanced Transcription from EσA- and EσE-Responsive Promoters by Phosphorylated PhoP

2004 ◽  
Vol 186 (13) ◽  
pp. 4262-4275 ◽  
Author(s):  
Salbi Paul ◽  
Stephanie Birkey ◽  
Wei Liu ◽  
F. Marion Hulett
Keyword(s):  
Bacillus Subtilis ◽  
Response Regulator ◽  
Phosphate Starvation ◽  
Growth Conditions ◽  
In Vitro Transcription ◽  
Phosphate Deficiency ◽  
Pho Regulon ◽  
Environmental Controls ◽  
Rna Polymerase Holoenzyme

ABSTRACT The phoPR operon encodes a response regulator, PhoP, and a histidine kinase, PhoR, which activate or repress genes of the Bacillus subtilis Pho regulon in response to an extracellular phosphate deficiency. Induction of phoPR upon phosphate starvation required activity of both PhoP and PhoR, suggesting autoregulation of the operon, a suggestion that is supported here by PhoP footprinting on the phoPR promoter. Primer extension analyses, using RNA from JH642 or isogenic sigE or sigB mutants isolated at different stages of growth and/or under different growth conditions, suggested that expression of the phoPR operon represents the sum of five promoters, each responding to a specific growth phase and environmental controls. The temporal expression of the phoPR promoters was investigated using in vitro transcription assays with RNA polymerase holoenzyme isolated at different stages of Pho induction, from JH642 or isogenic sigE or sigB mutants. In vitro transcription studies using reconstituted EσA, EσB, and EσE holoenzymes identified PA4 and PA3 as EσA promoters and PE2 as an EσE promoter. Phosphorylated PhoP (PhoP∼P) enhanced transcription from each of these promoters. EσB was sufficient for in vitro transcription of the PB1 promoter. P5 was active only in a sigB mutant strain. These studies are the first to report a role for PhoP∼P in activation of promoters that also have activity in the absence of Pho regulon induction and an activation role for PhoP∼P at an EσE promoter. Information concerning PB1 and P5 creates a basis for further exploration of the regulatory coordination or overlap of the PhoPR and SigB regulons during phosphate starvation.

scholarly journals Defining the core essential genome ofPseudomonas aeruginosa

2019 ◽  
Vol 116 (20) ◽  
pp. 10072-10080 ◽  
Author(s):  
Bradley E. Poulsen ◽  
Rui Yang ◽  
Anne E. Clatworthy ◽  
Tiantian White ◽  
Sarah J. Osmulski ◽  
...  
Keyword(s):  
Bacterial Species ◽  
Growth Conditions ◽  
Essential Genes ◽  
The Core ◽  
Transposon Insertion ◽  
Wide Range ◽  
Transposon Insertion Sequencing ◽  
Antibiotic Discovery

Genomics offered the promise of transforming antibiotic discovery by revealing many new essential genes as good targets, but the results fell short of the promise. While numerous factors contributed to the disappointing yield, one factor was that essential genes for a bacterial species were often defined based on a single or limited number of strains grown under a single or limited number of in vitro laboratory conditions. In fact, the essentiality of a gene can depend on both the genetic background and growth condition. We thus developed a strategy for more rigorously defining the core essential genome of a bacterial species by studying many pathogen strains and growth conditions. We assessed how many strains must be examined to converge on a set of core essential genes for a species. We used transposon insertion sequencing (Tn-Seq) to define essential genes in nine strains ofPseudomonas aeruginosaon five different media and developed a statistical model,FiTnEss, to classify genes as essential versus nonessential across all strain–medium combinations. We defined a set of 321 core essential genes, representing 6.6% of the genome. We determined that analysis of four strains was typically sufficient inP. aeruginosato converge on a set of core essential genes likely to be essential across the species across a wide range of conditions relevant to in vivo infection, and thus to represent attractive targets for novel drug discovery.

scholarly journals Homogeneity and heterogeneity in amylase production by Bacillus subtilis under different growth conditions

2016 ◽  
Vol 15 (1) ◽  
Author(s):  
Tina N. Ploss ◽  
Ewoud Reilman ◽  
Carmine G. Monteferrante ◽  
Emma L. Denham ◽  
Sjouke Piersma ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Growth Conditions ◽  
Amylase Production
Sign in / Sign up

Export Citation Format

Share Document