scholarly journals Surface-Associated Flagellum Formation and Swarming Differentiation in Bacillus subtilis Are Controlled by the ifm Locus

2004 ◽  
Vol 186 (4) ◽  
pp. 1158-1164 ◽  
Author(s):  
Sonia Senesi ◽  
Emilia Ghelardi ◽  
Francesco Celandroni ◽  
Sara Salvetti ◽  
Eva Parisio ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Solid Medium ◽  
Fold Increase ◽  
Solid Surfaces ◽  
Wild Type ◽  
Liquid Media ◽  
Flagellin Gene ◽  
Swarming Motility ◽  
Solid Media ◽  
Solid Substrates

ABSTRACT Knowledge of the highly regulated processes governing the production of flagella in Bacillus subtilis is the result of several observations obtained from growing this microorganism in liquid cultures. No information is available regarding the regulation of flagellar formation in B. subtilis in response to contact with a solid surface. One of the best-characterized responses of flagellated eubacteria to surfaces is swarming motility, a coordinate cell differentiation process that allows collective movement of bacteria over solid substrates. This study describes the swarming ability of a B. subtilis hypermotile mutant harboring a mutation in the ifm locus that has long been known to affect the degree of flagellation and motility in liquid media. On solid media, the mutant produces elongated and hyperflagellated cells displaying a 10-fold increase in extracellular flagellin. In contrast to the mutant, the parental strain, as well as other laboratory strains carrying a wild-type ifm locus, fails to activate a swarm response. Furthermore, it stops to produce flagella when transferred from liquid to solid medium. Evidence is provided that the absence of flagella is due to the lack of flagellin gene expression. However, restoration of flagellin synthesis in cells overexpressing σD or carrying a deletion of flgM does not recover the ability to assemble flagella. Thus, the ifm gene plays a determinantal role in the ability of B. subtilis to contact with solid surfaces.

scholarly journals Retarded swarming motility in Bacillus subtilis NRS-762 and Pseudomonas aeruginosa PRD-10

2018 ◽  
Author(s):  
Wenfa Ng
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacillus Subtilis ◽  
Bacterial Species ◽  
Nutritional Stress ◽  
Cellular Level ◽  
Bacterial Cells ◽  
Loss Of Function ◽  
Swarming Motility ◽  
Bacteria Growth ◽  
Solid Media

Coping with nutritional stress is essential for cell survival, of which many strategies at the cellular level lend support for ensuring the survival of the population at a particular habitat. One postulated mechanism is swarming motility in bacterial cells, where, upon depletion of nutrients at a locale, cells would coordinate their movement, synthesize more flagella, and secrete lubricants for moving rapidly across surfaces in search for food. Known to engage in swarming motility, Bacillus subtilis and Pseudomonas aeruginosa are two common bacterial species with versatile metabolism that use the motility mode to colonize new habitats with more favourable environmental and nutritional conditions. However, experimental observations of bacteria growth on a variety of agar media revealed that B. subtilis NRS-762 (ATCC 8473) and P. aeruginosa PRD-10 (ATCC 15442) exhibited retarded swarming motility upon entry into stationary phase on solid media. Specifically, B. subtilis NRS-762 colonies exhibited round, wrinkled morphologies compared to complex filamented swarming patterns common in strains able to engage in swarming motility. On the other hand, P. aeruginosa PRD-10 colonies were round, mucoid, and expanded outwards from the colony centre without extending filaments from the centre; thereby, indicating retarded swarming motility. Thus, impaired cellular machinery for swarming motility or mutated and deleted genes likely account for observed retarded swarming motility in B. subtilis NRS-762 and P. aeruginosa PRD-10. More importantly, observations of small filaments extending radially from an expanded colony of P. aeruginosa PRD-10 grown on minimal salts medium supplemented with yeast extract highlighted possible loss of function of effector molecules that transmit cellular decision at swarming motility into movement, while sensory mechanisms feeding into the motility mechanism remained intact. More broadly, observations of impaired swarming motility in B. subtilis NRS-762 and P. aeruginosa PRD-10 in two species otherwise endowed with the motility mode highlighted that additional triggers for swarming motility are likely present, and the motility mode may have been evolutionary selected for other functions in addition to foraging for food in times of nutritional stress.

scholarly journals FlhF Is Required for Swimming and Swarming in Pseudomonas aeruginosa

2006 ◽  
Vol 188 (19) ◽  
pp. 6995-7004 ◽  
Author(s):  
Thomas S. Murray ◽  
Barbara I. Kazmierczak
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Cell Surface ◽  
Signal Recognition Particle ◽  
Signal Recognition ◽  
Wild Type ◽  
Liquid Media ◽  
Swarming Motility ◽  
Flagellar Assembly ◽  
Swarming Behavior ◽  
Flagellar Genes

ABSTRACT FlhF is a signal recognition particle-like protein present in monotrichous bacteria. The loss of FlhF in various bacteria results in decreased transcription of class II, III, or IV flagellar genes, leads to diminished or absent motility, and results in the assembly of flagella at nonpolar locations on the cell surface. In this work, we demonstrate that the loss of FlhF results in defective swimming and swarming motility of Pseudomonas aeruginosa. The FlhF protein localizes to the flagellar pole; in the absence of FlhF, flagellar assembly occurs but is no longer restricted to the pole. ΔflhF bacteria swim at lower velocities than wild-type bacteria in liquid media and can no longer swarm when assayed under standard swarming conditions (0.5% agar). However, ΔflhF bacteria regain swarming behavior when plated on 0.3% agar. ΔflhF organisms show decreased transcription and expression of flagellin (FliC) both in liquid media and on swarming plates compared to wild-type bacteria. However, changes in flagellin expression do not explain the different motility patterns observed for ΔflhF bacteria. Instead, the aberrant placement of flagella in ΔflhF bacteria may reduce their ability to move this rod-shaped organism effectively.

scholarly journals Conjugal Transfer but Not Quorum-Dependenttra Gene Induction of pTiC58 Requires a Solid Surface

1999 ◽  
Vol 65 (6) ◽  
pp. 2798-2801 ◽  
Author(s):  
Kevin R. Piper ◽  
Stephen K. Farrand
Keyword(s):  
Gene Expression ◽  
Agrobacterium Tumefaciens ◽  
Liquid Medium ◽  
Solid Surface ◽  
High Frequency ◽  
Solid Medium ◽  
Regulatory System ◽  
Ti Plasmid ◽  
Solid Surfaces ◽  
Wild Type

ABSTRACT Donors of Agrobacterium tumefaciens harboring a transfer-constitutive derivative of the nopaline-type Ti plasmid pTiC58 transferred this element at frequencies 3 to 4 orders of magnitude higher in matings conducted on solid surfaces than in those conducted in liquid medium. However, as measured with a lacZ reporter fusion, the tra genes of the wild-type Ti plasmid were inducible by opines to indistinguishable levels on solid and in liquid medium. Donors induced in liquid transferred the Ti plasmid at high frequency when mated with recipients on solid medium. We conclude that while formation of stable mating pairs and subsequent transfer of the Ti plasmid is dependent on a solid stratum, the regulatory system can activate tra gene expression to equivalent levels in liquid and on solid surfaces.

scholarly journals Characterization of Colony Morphology Variants Isolated from Pseudomonas aeruginosa Biofilms

2005 ◽  
Vol 71 (8) ◽  
pp. 4809-4821 ◽  
Author(s):  
Mary Jo Kirisits ◽  
Lynne Prost ◽  
Melissa Starkey ◽  
Matthew R. Parsek
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Solid Medium ◽  
Three Dimensional ◽  
Solid Surfaces ◽  
Colony Morphology ◽  
Dimensional Structure ◽  
Wild Type ◽  
Wild Type Parent

ABSTRACT In this study, we report the isolation of small, rough, strongly cohesive colony morphology variants from aging Pseudomonas aeruginosa PAO1 biofilms. Similar to many of the P. aeruginosa colony morphology variants previously described in the literature, these variants autoaggregate in liquid culture and hyperadhere to solid surfaces. They also exhibit increased hydrophobicity and reduced motility compared to the wild-type parent strain. Despite the similarities in appearance of our colony morphology variant isolates on solid medium, the isolates showed a range of responses in various phenotypic assays. These variants form biofilms with significant three-dimensional structure and more biomass than the wild-type parent. To further explore the nature of the variants, their transcriptional profiles were evaluated. The variants generally showed increased expression of the psl and pel loci, which have been previously implicated in the adherence of P. aeruginosa to solid surfaces. When a mutation in the psl locus was introduced into a colony morphology variant, the colony morphology was only partially affected, but hyperadherence and autoaggregation were lost. Finally, similar colony morphology variants were found in isolates from cystic fibrosis patients. These variants displayed many of the same characteristics as the laboratory variants, suggesting a link between laboratory and cystic fibrosis biofilms.

scholarly journals Swarming Differentiation and Swimming Motility in Bacillus subtilis Are Controlled by swrA, a Newly Identified Dicistronic Operon

2005 ◽  
Vol 187 (15) ◽  
pp. 5356-5366 ◽  
Author(s):  
Cinzia Calvio ◽  
Francesco Celandroni ◽  
Emilia Ghelardi ◽  
Giuseppe Amati ◽  
Sara Salvetti ◽  
...  
Keyword(s):  
Functional Analysis ◽  
Bacillus Subtilis ◽  
Preliminary Data ◽  
Solid Surfaces ◽  
Cell Contact ◽  
Gene Products ◽  
Swimming Motility ◽  
Solid Media ◽  
Specific Trait

ABSTRACT The number and disposition of flagella harbored by eubacteria are regulated by a specific trait successfully maintained over generations. The genes governing the number of flagella in Bacillus subtilis have never been identified, although the ifm locus has long been recognized to influence the motility phenotype of this microorganism. The characterization of a spontaneous ifm mutant of B. subtilis, displaying diverse degrees of cell flagellation in both liquid and solid media, raised the question of how the ifm locus governs the number and assembly of functional flagella. The major finding of this investigation is the characterization of a newly identified dicistronic operon, named swrA, that controls both swimming motility and swarming differentiation in B. subtilis. Functional analysis of the swrA operon allowed swrAA (previously named swrA [D. B. Kearns, F. Chu, R. Rudner, and R. Losick, Mol. Microbiol. 52:357-369, 2004]) to be the first gene identified in B. subtilis that controls the number of flagella in liquid environments and the assembly of flagella in response to cell contact with solid surfaces. Evidence is given that the second gene of the operon, swrAB, is essential for enabling the surface-adhering cells to undergo swarming differentiation. Preliminary data point to a molecular interaction between the two gene products.

scholarly journals Retarded swarming motility in Bacillus subtilis NRS-762 and Pseudomonas aeruginosa PRD-10

2018 ◽  
Author(s):  
Wenfa Ng
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacillus Subtilis ◽  
Bacterial Species ◽  
Nutritional Stress ◽  
Cellular Level ◽  
Bacterial Cells ◽  
Loss Of Function ◽  
Swarming Motility ◽  
Bacteria Growth ◽  
Solid Media

Coping with nutritional stress is essential for cell survival, of which many strategies at the cellular level lend support for ensuring the survival of the population at a particular habitat. One postulated mechanism is swarming motility in bacterial cells, where, upon depletion of nutrients at a locale, cells would coordinate their movement, synthesize more flagella, and secrete lubricants for moving rapidly across surfaces in search for food. Known to engage in swarming motility, Bacillus subtilis and Pseudomonas aeruginosa are two common bacterial species with versatile metabolism that use the motility mode to colonize new habitats with more favourable environmental and nutritional conditions. However, experimental observations of bacteria growth on a variety of agar media revealed that B. subtilis NRS-762 (ATCC 8473) and P. aeruginosa PRD-10 (ATCC 15442) exhibited retarded swarming motility upon entry into stationary phase on solid media. Specifically, B. subtilis NRS-762 colonies exhibited round, wrinkled morphologies compared to complex filamented swarming patterns common in strains able to engage in swarming motility. On the other hand, P. aeruginosa PRD-10 colonies were round, mucoid, and expanded outwards from the colony centre without extending filaments from the centre; thereby, indicating retarded swarming motility. Thus, impaired cellular machinery for swarming motility or mutated and deleted genes likely account for observed retarded swarming motility in B. subtilis NRS-762 and P. aeruginosa PRD-10. More importantly, observations of small filaments extending radially from an expanded colony of P. aeruginosa PRD-10 grown on minimal salts medium supplemented with yeast extract highlighted possible loss of function of effector molecules that transmit cellular decision at swarming motility into movement, while sensory mechanisms feeding into the motility mechanism remained intact. More broadly, observations of impaired swarming motility in B. subtilis NRS-762 and P. aeruginosa PRD-10 in two species otherwise endowed with the motility mode highlighted that additional triggers for swarming motility are likely present, and the motility mode may have been evolutionary selected for other functions in addition to foraging for food in times of nutritional stress.

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).

Ultrastructure and Morphology of the Neurospora Crassa Cell Wall Mutants, Slime And Slime X, Using Tem and Sem

1976 ◽  
Vol 34 ◽  
pp. 54-55
Author(s):  
Karen S. Howard ◽  
H. D. Braymer ◽  
M. D. Socolofsky ◽  
S. A. Milligan
Keyword(s):  
Cell Wall ◽  
Neurospora Crassa ◽  
Wild Type ◽  
Morphological Comparison ◽  
Small Areas ◽  
Solid Media ◽  
Thin Sectioning ◽  
X Cells ◽  
Mutant Cells ◽  
Isolated Cell

The recently isolated cell wall mutant slime X of Neurospora crassa was prepared for ultrastructural and morphological comparison with the cell wall mutant slime. The purpose of this article is to discuss the methods of preparation for TEM and SEM observations, as well as to make a preliminary comparison of the two mutants.TEM: Cells of the slime mutant were prepared for thin sectioning by the method of Bigger, et al. Slime X cells were prepared in the same manner with the following two exceptions: the cells were embedded in 3% agar prior to fixation and the buffered solutions contained 5% sucrose throughout the procedure.SEM: Two methods were used to prepare mutant and wild type Neurospora for the SEM. First, single colonies of mutant cells and small areas of wild type hyphae were cut from solid media and fixed with OSO4 vapors similar to the procedure used by Harris, et al. with one alteration. The cell-containing agar blocks were dehydrated by immersion in 2,2-dimethoxypropane (DMP).

Improved Production of Two Anti-Candida Lipopeptide Homologues Co- Produced by the Wild-Type Bacillus subtilis RLID 12.1 under Optimized Conditions

2020 ◽  
Vol 21 (5) ◽  
pp. 438-450
Author(s):  
Ramya Ramchandran ◽  
Swetha Ramesh ◽  
Anviksha A ◽  
RamLal Thakur ◽  
Arunaloke Chakrabarti ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Pathogenic Fungi ◽  
Fold Increase ◽  
Production Yield ◽  
Yield Enhancement ◽  
Bioactive Metabolites ◽  
Candida Auris ◽  
Media Formulation ◽  
Static Conditions

Background:: Antifungal cyclic lipopeptides, bioactive metabolites produced by many species of the genus Bacillus, are promising alternatives to synthetic fungicides and antibiotics for the biocontrol of human pathogenic fungi. In a previous study, the co- production of five antifungal lipopeptides homologues (designated as AF1, AF2, AF3, AF4 and AF5) by the producer strain Bacillus subtilis RLID 12.1 using unoptimized medium was reported; though the two homologues AF3 and AF5 differed by 14 Da and in fatty acid chain length were found effective in antifungal action, the production/ yield rate of these two lipopeptides determined by High-Performance Liquid Chromatography was less in the unoptimized media. Methods:: In this study, the production/yield enhancement of the two compounds AF3 and AF5 was specifically targeted. Following the statistical optimization (Plackett-Burman and Box-Behnken designs) of media formulation, temperature and growth conditions, the production of AF3 and AF5 was improved by about 25.8- and 7.4-folds, respectively under static conditions. Results:: To boost the production of these two homologous lipopeptides in the optimized media, heat-inactivated Candida albicans cells were used as a supplement resulting in 34- and 14-fold increase of AF3 and AF5, respectively. Four clinical Candida auris isolates had AF3 and AF5 MICs (100 % inhibition) ranging between 4 and 16 μg/ml indicating the lipopeptide’s clinical potential. To determine the in vitro pharmacodynamic potential of AF3 and AF5, time-kill assays were conducted which showed that AF3 (at 4X and 8X concentrations) at 48h exhibited mean log reductions of 2.31 and 3.14 CFU/ml of C. albicans SC 5314, respectively whereas AF5 at 8X concentration showed a mean log reduction of 2.14 CFU/ml. Conclusion:: With the increasing threat of multidrug-resistant yeasts and fungi, these antifungal lipopeptides produced by optimized method promise to aid in the development of novel antifungal that targets disease-causing fungi with improved efficacy.

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