scholarly journals Quantification and Isolation ofBacillus subtilisSpores using Cell Sorting and automated Gating

2019 ◽  
Author(s):  
Marianna Karava ◽  
Felix Bracharz ◽  
Johannes Kabisch

AbstractThe Gram-positive bacteriumBacillus subtilisis able to form endospores which have a variety of biotechnological applications. Due to this ability,B. subtilisis as well a model organism for cellular differentiation processes. Sporulating cultures ofBacillus subtilisform sub-populations which include vegetative cells, spore forming cells and spores. In order to readily and rapidly quantify spore formation we employed flow cytometric and fluorescence activated cell sorting techniques in combination with nucleic acid fluorescent staining in order to investigate the distribution of sporulating cultures on a single cell level. Moreover we tested different fluorescent dyes as well as different conditions in order to develop a method for optimal separation of distinct populations during sporulation. Automated gating procedures using k-means clustering and thresholding by gaussian mixture modeling were employed to avoid subjective gating and allow for the simultaneous measurement of controls. We utilized the presented method for monitoring sporulation over time in strains harboring different genome modifications. We identified the different subpopulations formed during sporulation by employing sorting and microscopy. Finally, we employed the technique to show that a double knock-out mutant of the phosphatase gene encoding Spo0E and of the spore killing factor SkfA results in faster spore formation.

2020 ◽  
Vol 401 (12) ◽  
pp. 1307-1322
Author(s):  
Gert Bange ◽  
Patricia Bedrunka

AbstractThe guanosine-based second messengers (p)ppGpp and c-di-GMP are key players of the physiological regulation of the Gram-positive model organism Bacillus subtilis. Their regulatory spectrum ranges from key metabolic processes over motility to biofilm formation. Here we review our mechanistic knowledge on their synthesis and degradation in response to environmental and stress signals as well as what is known on their cellular effectors and targets. Moreover, we discuss open questions and our gaps in knowledge on these two important second messengers.


DNA Sequence ◽  
1991 ◽  
Vol 1 (4) ◽  
pp. 251-261 ◽  
Author(s):  
P. Glaser ◽  
F. Kunst ◽  
M. Débarbouillé ◽  
A. Vertès ◽  
A. Danchin ◽  
...  

2002 ◽  
Vol 184 (22) ◽  
pp. 6123-6129 ◽  
Author(s):  
Min Cao ◽  
John D. Helmann

ABSTRACT Bacitracin resistance is normally conferred by either of two major mechanisms, the BcrABC transporter, which pumps out bacitracin, or BacA, an undecaprenol kinase that provides C55-isoprenyl phosphate by de novo synthesis. We demonstrate that the Bacillus subtilis bcrC (ywoA) gene, encoding a putative bacitracin transport permease, is an important bacitracin resistance determinant. A bcrC mutant strain had an eightfold-higher sensitivity to bacitracin. Expression of bcrC initiated from a single promoter site that could be recognized by either of two extracytoplasmic function (ECF) σ factors, σX or σM. Bacitracin induced expression of bcrC, and this induction was dependent on σM but not on σX. Under inducing conditions, expression was primarily dependent on σM. As a consequence, a sigM mutant was fourfold more sensitive to bacitracin, while the sigX mutant was only slightly sensitive. A sigX sigM double mutant was similar to a bcrC mutant in sensitivity. These results support the suggestion that one function of B. subtilis ECF σ factors is to coordinate antibiotic stress responses.


Microbiology ◽  
2005 ◽  
Vol 151 (3) ◽  
pp. 999-1012 ◽  
Author(s):  
Dirk-Jan Scheffers

During Bacillus subtilis spore formation, many membrane proteins that function in spore development localize to the prespore septum and, subsequently, to the outer prespore membrane. Recently, it was shown that the cell-division-specific penicillin-binding proteins (PBPs) 1 and 2b localize to the asymmetric prespore septum. Here, the author studied the localization of other PBPs, fused to green fluorescent protein (GFP), during spore formation. Fusions to PBPs 4, 2c, 2d, 2a, 3, H, 4b, 5, 4a, 4* and X were expressed during vegetative growth, and their localization was monitored during sporulation. Of these PBPs, 2c, 2d, 4b and 4* have been implicated as having a function in sporulation. It was found that PBP2c, 2d and X changed their localization, while the other PBPs tested were not affected. The putative endopeptidase PbpX appears to spiral out in a pattern that resembles FtsZ redistribution during sporulation, but a pbpX knockout strain had no distinguishable phenotype. PBP2c and 2d localize to the prespore septum and follow the membrane during engulfment, and so are redistributed to the prespore membrane. A similar pattern was observed when GFP–PBP2c was expressed in the mother cell from a sporulation-specific promoter. This work shows that various PBPs known to function during sporulation are redistributed from the cytoplasmic membrane to the prespore.


2004 ◽  
Vol 186 (14) ◽  
pp. 4528-4534 ◽  
Author(s):  
Nicola Zamboni ◽  
Eliane Fischer ◽  
Dietmar Laudert ◽  
Stéphane Aymerich ◽  
Hans-Peter Hohmann ◽  
...  

ABSTRACT Despite the importance of the oxidative pentose phosphate (PP) pathway as a major source of reducing power and metabolic intermediates for biosynthetic processes, almost no direct genetic or biochemical evidence is available for Bacillus subtilis. Using a combination of knockout mutations in known and putative genes of the oxidative PP pathway and 13C-labeling experiments, we demonstrated that yqjI encodes the NADP+-dependent 6-P-gluconate dehydrogenase, as was hypothesized previously from sequence similarities. Moreover, YqjI was the predominant isoenzyme during glucose and gluconate catabolism, and its role in the oxidative PP pathway could not be played by either of two homologues, GntZ and YqeC. This conclusion is in contrast to the generally held view that GntZ is the relevant isoform; hence, we propose a new designation for yqjI, gndA, the monocistronic gene encoding the principal 6-P-gluconate dehydrogenase. Although we demonstrated the NAD+-dependent 6-P-gluconate dehydrogenase activity of GntZ, gntZ mutants exhibited no detectable phenotype on glucose, and GntZ did not contribute to PP pathway fluxes during growth on glucose. Since gntZ mutants grew normally on gluconate, the functional role of GntZ remains obscure, as does the role of the third homologue, YqeC. Knockout of the glucose-6-P dehydrogenase-encoding zwf gene was primarily compensated for by increased glycolytic fluxes, but about 5% of the catabolic flux was rerouted through the gluconate bypass with glucose dehydrogenase as the key enzyme.


2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Cristi L Galindo ◽  
Truc-Linh Tran ◽  
Xuyang Peng ◽  
Douglas B Sawyer ◽  
Mary Asson-Batres

Vitamin A (VA) is the chemical precursor of retinoic acid (RA), which is critical for embryonic development and for growth, immunity, metabolism, and cell differentiation in postnatal regenerating systems such as skin, sensory organs, and stem cell niches in the brain. VA is also essential for embryonic heart development, and we hypothesized that Vitamin A might exert an effect on the postnatal heart similar to what is observed for other tissues. Here, we report the global transcriptional profiles of wild-type (WT) mice fed a VA sufficient diet (VAS) compared with retinyl acyl transferase (LRAT) knock-out mice fed either a VAS or VA deficient (VAD) diet. Knockout of the LRAT gene alone was sufficient to induce differential expression of 576 genes relative to WT. Feeding LRAT mutant mice a VAD diet resulted in a change in the relative expression levels of 257 genes relative to LRAT mutant mice fed a VAS diet. As expected, we observed transcriptional alterations related to Vitamin A metabolism, including an increase in the gene encoding cellular retinoid binding protein 7 and down-regulation of the retinol metabolic enzymes Cy1a2 and Cyp2a4. Importantly, several cardiac genes not previously known to require VA were perturbed, including the gene encoding B-type natriuretic peptide, which was down-regulated in mutant mice irrespective of diet, and A-type natriuretic peptide, which was decreased only in mice fed the VAD diet. There was also a striking effect of VAD on genes important for immune responses, which could have an impact on the wound healing process subsequent to injury of the heart. This is consistent with recent evidence that showed that Vitamin A deficiency influences post-infarct ventricular remodeling in rats. In summary, this is the first microarray study of Vitamin A deficiency in the postnatal heart, which suggests mechanisms by which Vitamin A depletion may alter myocardial maintenance and repair after injury.


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