scholarly journals SwrD (YlzI) Promotes Swarming in Bacillus subtilis by Increasing Power to Flagellar Motors

2017 ◽  
Vol 200 (2) ◽  
Author(s):  
Ashley N. Hall ◽  
Sundharraman Subramanian ◽  
Reid T. Oshiro ◽  
Alexandra K. Canzoneri ◽  
Daniel B. Kearns
Keyword(s):  
Bacillus Subtilis ◽  
Swarming Motility ◽  
Content Type ◽  
Flagellar Motors ◽  
Artificial Induction ◽  
Flagellar Biosynthesis ◽  
Surfactant Production ◽  
New Gene ◽  
The Difference ◽  
Power Mutation

ABSTRACTThe bacteriumBacillus subtilisis capable of two kinds of flagellum-mediated motility: swimming, which occurs in liquid, and swarming, which occurs on a surface. Swarming is distinct from swimming in that it requires secretion of a surfactant, an increase in flagellar density, and perhaps additional factors. Here we report a new gene,swrD, located within the 32 genefla-cheoperon dedicated to flagellar biosynthesis and chemotaxis, which when mutated abolished swarming motility. SwrD was not required for surfactant production, flagellar gene expression, or an increase in flagellar number. Instead, SwrD was required to increase flagellar power. Mutation ofswrDreduced swimming speed and torque of tethered flagella, and allswrD-related phenotypes were restored when the stator subunits MotA and MotB were overexpressed either by spontaneous suppressor mutations or by artificial induction. We conclude that swarming motility requires flagellar power in excess of that which is needed to swim.IMPORTANCEBacteria swim in liquid and swarm over surfaces by rotating flagella, but the difference between swimming and swarming is poorly understood. Here we report that SwrD ofBacillus subtilisis necessary for swarming because it increases flagellar torque and cells mutated forswrDswim with reduced speed. How flagellar motors generate power is primarily studied inEscherichia coli, and SwrD likely increases power in other organisms, like theFirmicutes,Clostridia,Spirochaetes, and theDeltaproteobacteria.

scholarly journals The C-Terminal Region ofBacillus subtilisSwrA Is Required for Activity and Adaptor-Dependent LonA Proteolysis

2018 ◽  
Vol 200 (6) ◽  
Author(s):  
Anna C. Hughes ◽  
Sundharraman Subramanian ◽  
Charles E. Dann ◽  
Daniel B. Kearns
Keyword(s):  
Bacillus Subtilis ◽  
Transcriptional Activation ◽  
Adaptor Protein ◽  
Terminal Region ◽  
Cell Contact ◽  
Loss Of Function ◽  
Gain Of Function ◽  
Swarming Motility ◽  
Content Type ◽  
Flagellar Biosynthesis

ABSTRACTSwrA is the master activator of flagellar biosynthesis inBacillus subtilis, and SwrA activity is restricted by regulatory proteolysis in liquid environments. SwrA is proteolyzed by the LonA protease but requires a proteolytic adaptor protein, SmiA. Here, we show that SwrA and SmiA interact directly. To better understand SwrA activity, SwrA was randomly mutagenized and loss-of-function and gain-of-function mutants were localized primarily to the predicted unstructured C-terminal region. The loss-of-function mutations impaired swarming motility and activation from thePfla-chepromoter. The gain-of-function mutations increased protein stability but did not abolish SmiA binding, suggesting that SmiA association was a precursor to, but not sufficient for, LonA-dependent proteolysis. Finally, one allele abolished simultaneously SwrA activity and regulatory proteolysis, suggesting that the two functions may be in steric competition.IMPORTANCESwrA is the master activator of flagellar biosynthesis inBacillus subtilis, and its mechanism of activation is poorly understood. Moreover, SwrA levels are restricted by SmiA, the first adaptor protein reported for the Lon family of proteases. Here, we show that the C-terminal region of SwrA is important for both transcriptional activation and regulatory proteolysis. Competition between the two processes at this region may be critical for responding to cell contact with a solid surface and the initiation of swarming motility.

scholarly journals Nonribosomal Peptide Synthase Gene Clusters for Lipopeptide Biosynthesis in Bacillus subtilis 916 and Their Phenotypic Functions

2014 ◽  
Vol 81 (1) ◽  
pp. 422-431 ◽  
Author(s):  
Chuping Luo ◽  
Xuehui Liu ◽  
Huafei Zhou ◽  
Xiaoyu Wang ◽  
Zhiyi Chen
Keyword(s):  
Bacillus Subtilis ◽  
Antifungal Activity ◽  
Hemolytic Activity ◽  
Biofilm Formation ◽  
Gene Clusters ◽  
Colony Morphology ◽  
Swarming Motility ◽  
Nonribosomal Peptide ◽  
Content Type ◽  
Phenotypic Features

ABSTRACTBacilluscyclic lipopeptides (LPs) have been well studied for their phytopathogen-antagonistic activities. Recently, research has shown that these LPs also contribute to the phenotypic features ofBacillusstrains, such as hemolytic activity, swarming motility, biofilm formation, and colony morphology.Bacillus subtilis916 not only coproduces the three families of well-known LPs, i.e., surfactins, bacillomycin Ls (iturin family), and fengycins, but also produces a new family of LP called locillomycins. The genome ofB. subtilis916 contains four nonribosomal peptide synthase (NRPS) gene clusters,srf,bmy,fen, andloc, which are responsible for the biosynthesis of surfactins, bacillomycin Ls, fengycins, and locillomycins, respectively. By studyingB. subtilis916 mutants lacking production of one, two, or three LPs, we attempted to unveil the connections between LPs and phenotypic features. We demonstrated that bacillomycin Ls and fengycins contribute mainly to antifungal activity. Although surfactins have weak antifungal activityin vitro, the strain mutated insrfAAhad significantly decreased antifungal activity. This may be due to the impaired productions of fengycins and bacillomycin Ls. We also found that the disruption of any LP gene cluster other thanfenresulted in a change in colony morphology. While surfactins and bacillomycin Ls play very important roles in hemolytic activity, swarming motility, and biofilm formation, the fengycins and locillomycins had little influence on these phenotypic features. In conclusion,B. subtilis916 coproduces four families of LPs which contribute to the phenotypic features ofB. subtilis916 in an intricate way.

scholarly journals Effects of Sporulation Conditions on the Germination and Germination Protein Levels of Bacillus subtilis Spores

2012 ◽  
Vol 78 (8) ◽  
pp. 2689-2697 ◽  
Author(s):  
Arturo Ramirez-Peralta ◽  
Pengfei Zhang ◽  
Yong-qing Li ◽  
Peter Setlow
Keyword(s):  
Bacillus Subtilis ◽  
Spore Germination ◽  
Dipicolinic Acid ◽  
Rich Medium ◽  
Microscope Slide ◽  
Content Type ◽  
Protein Levels ◽  
Germination Characteristics ◽  
The Difference ◽  
Lag Times

ABSTRACTBacillus subtilisspores prepared in rich medium germinated faster with nutrient germinants than poor-medium spores as populations in liquid and multiple individual spores on a microscope slide. Poor-medium spores had longer average lag times between mixing of spores with nutrient germinants and initiation of Ca-dipicolinic acid (CaDPA) release. Rich-medium spores made at 37°C germinated slightly faster with nutrient germinants than 23°C spores in liquid, but not when spores germinated on a slide. The difference in germination characteristics of these spore populations in liquid was paralleled by changes in expression levels of a transcriptionallacZfusion to thegerAoperon, encoding a germinant receptor (GR). Levels of GR subunits were 3- to 8-fold lower in poor-medium spores than rich-medium spores and 1.6- to 2-fold lower in 23°C spores than 37°C spores, and levels of the auxiliary germination protein GerD were 3.5- to 4-fold lower in poor medium and 23°C spores. In contrast, levels of another likely germination protein, SpoVAD, were similar in all these spores. These different spores germinated similarly with CaDPA, and poor-medium and 23°C spores germinated faster than rich-medium and 37°C spores, respectively, with dodecylamine. Since spore germination with CaDPA and dodecylamine does not require GerD or GRs, these results indicate that determinants of rates of nutrient germination of spores prepared differently are primarily the levels of the GRs that bind nutrient germinants and trigger germination and secondarily the levels of GerD.

scholarly journals Biofilm formation by Bacillus subtilis is altered in the presence of pesticides

2020 ◽  
Vol 2 (12) ◽  
Author(s):  
Rachael Newton ◽  
Jennifer Amstutz ◽  
Joyce E. Patrick
Keyword(s):  
Bacillus Subtilis ◽  
Biofilm Formation ◽  
Type Species ◽  
Symbiotic Relationship ◽  
Neem Oil ◽  
Swarming Motility ◽  
Content Type ◽  
Future Studies ◽  
Link Type

Bacillus subtilis uses swarming motility and biofilm formation to colonize plant roots and form a symbiotic relationship with the plant. Swarming motility and biofilm formation are group behaviours made possible through the use of chemical messengers. We investigated whether chemicals applied to plants would interfere with the swarming motility and biofilm-forming capabilities of B. subtilis in vitro. We hypothesized that pesticides could act as chemical signals that influence bacterial behaviour; this research investigates whether swarming motility and biofilm formation of B. subtilis is affected by the application of the commercial pesticides with the active ingredients of neem oil, pyrethrin, or malathion. The results indicate that all three pesticides inhibit biofilm formation. Swarming motility is not affected by the application of pyrethrin or malathion, but swarm expansion and pattern is altered in the presence of neem oil. Future studies to investigate the mechanism by which pesticides alter biofilm formation are warranted.

scholarly journals CwlQ is required for swarming motility but not flagellar assembly in Bacillus subtilis

2021 ◽  
Author(s):  
Sandra Sanchez ◽  
Caroline M Dunn ◽  
Daniel B. Kearns
Keyword(s):  
Bacillus Subtilis ◽  
Candidate Gene ◽  
Candidate Gene Approach ◽  
Reverse Genetic ◽  
Cell Integrity ◽  
Lytic Enzymes ◽  
Swarming Motility ◽  
Lytic Transglycosylase ◽  
Flagellar Biosynthesis ◽  
Flagellar Assembly

Lytic enzymes play an essential role in the remodeling of bacterial peptidoglycan (PG), an extracellular mesh-like structure that retains the membrane in the context of high internal osmotic pressure. Peptidoglycan (PG) must be unfailingly stable to preserve cell integrity but must also be dynamically remodeled for the cell grow, divide and insert macromolecular machines. The flagellum is one such macromolecular machine that transits the PG and flagellar insertion is aided by localized activity of a dedicated PG lyase in Gram-negative bacteria. To date, there is no known dedicated lyase in Gram-positive bacteria for the insertion of flagella and here we take a reverse-genetic candidate-gene approach and find that cells mutated for the lytic transglycosylase CwlQ exhibited a severe defect in flagellar-dependent swarming motility. We further show that CwlQ was expressed by the motility sigma factor SigD and was secreted by the type III secretion system housed inside the flagellum. Nonetheless, cells mutated for CwlQ remained proficient for flagellar biosynthesis even when mutated in combination with four other lyases related to motility (LytC, LytD, LytF, and CwlO). The PG lyase or lyases essential for flagellar synthesis in B. subtilis, if any, remains unknown. IMPORTANCE Bacteria are surrounded by a wall of peptidoglycan and early work in Bacillus subtilis was the first to suggest that bacteria needed to enzymatically remodel the wall to permit insertion of the flagellum. No PG remodeling enzyme alone or in combination however, has been found to be essential for flagellar assembly in B. subtilis. Here we take a reverse genetic candidate gene approach and find that the PG lytic transglycosylase CwlQ is required for swarming motility. Subsequent characterization determined that while CwlQ was co-expressed with motility genes and is secreted by the flagellar secretion apparatus, it was not required for flagellar synthesis. The PG lyase needed for flagellar assembly in B. subtilis remains unknown.

What makes the difference? Employee social media brand engagement

2019 ◽  
Vol 34 (7) ◽  
pp. 1459-1467 ◽  
Author(s):  
Sherese Y. Duncan ◽  
Raeesah Chohan ◽  
João José Ferreira
Keyword(s):  
Social Media ◽  
Brand Equity ◽  
Positive Emotions ◽  
Content Type ◽  
Word Use ◽  
Brand Engagement ◽  
Analytical Thinking ◽  
Industry Competition ◽  
The Difference ◽  
Business To Business

Purpose This paper aims to explore, using the employee lens of business-to-business firms, word use through brand engagement and social media interaction to understand the difference between employees who rate their employer brands highly on social media and those who don't. Design/methodology/approach We conducted a textual content analysis of posts published on the social media job evaluation site glassdoor.com. LIWC software package was used to analyze 30 of the top 200 business-to-business brands listed on Brandwatch using four variables, namely, analytical thinking, clout, authenticity and emotional tone. Findings The results show that employees who rate their employer’s brand low use significantly more words, are significantly less analytic and write with significantly more clout because they focus more on others than themselves. Employees who rate their employer’s brand highly, write with significantly more authenticity, exhibit a significantly higher tone and display far more positive emotions in their reviews. Practical implications Brand managers should treat social media data disseminated by individual stakeholders, like the variables used in this study (tone, word count, frequency), as a valuable tool for brand insight on their industry, competition and their own brand equity, now and especially over time. Originality/value This study provides acknowledgement that social media is a significant source of marketing intelligence that may improve brand equity by better understanding and managing brand engagement.

scholarly journals Interdependent YpsA- and YfhS-Mediated Cell Division and Cell Size Phenotypes in Bacillus subtilis

mSphere ◽  
2020 ◽  
Vol 5 (4) ◽  
Author(s):  
Robert S. Brzozowski ◽  
Brooke R. Tomlinson ◽  
Michael D. Sacco ◽  
Judy J. Chen ◽  
Anika N. Ali ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Cell Division ◽  
Cell Size ◽  
Unknown Function ◽  
Suppressor Mutation ◽  
Gram Positive ◽  
Content Type ◽  
Suppressor Mutations ◽  
Extragenic Suppressor ◽  
Cell Division Inhibition

ABSTRACT Although many bacterial cell division factors have been uncovered over the years, evidence from recent studies points to the existence of yet-to-be-discovered factors involved in cell division regulation. Thus, it is important to identify factors and conditions that regulate cell division to obtain a better understanding of this fundamental biological process. We recently reported that in the Gram-positive organisms Bacillus subtilis and Staphylococcus aureus, increased production of YpsA resulted in cell division inhibition. In this study, we isolated spontaneous suppressor mutations to uncover critical residues of YpsA and the pathways through which YpsA may exert its function. Using this technique, we were able to isolate four unique intragenic suppressor mutations in ypsA (E55D, P79L, R111P, and G132E) that rendered the mutated YpsA nontoxic upon overproduction. We also isolated an extragenic suppressor mutation in yfhS, a gene that encodes a protein of unknown function. Subsequent analysis confirmed that cells lacking yfhS were unable to undergo filamentation in response to YpsA overproduction. We also serendipitously discovered that YfhS may play a role in cell size regulation. Finally, we provide evidence showing a mechanistic link between YpsA and YfhS. IMPORTANCE Bacillus subtilis is a rod-shaped Gram-positive model organism. The factors fundamental to the maintenance of cell shape and cell division are of major interest. We show that increased expression of ypsA results in cell division inhibition and impairment of colony formation on solid medium. Colonies that do arise possess compensatory suppressor mutations. We have isolated multiple intragenic (within ypsA) mutants and an extragenic suppressor mutant. Further analysis of the extragenic suppressor mutation led to a protein of unknown function, YfhS, which appears to play a role in regulating cell size. In addition to confirming that the cell division phenotype associated with YpsA is disrupted in a yfhS-null strain, we also discovered that the cell size phenotype of the yfhS knockout mutant is abolished in a strain that also lacks ypsA. This highlights a potential mechanistic link between these two proteins; however, the underlying molecular mechanism remains to be elucidated.

Disposition effect at the market level: evidence from Indian stock market

2019 ◽  
Vol 12 (2) ◽  
pp. 69-82
Author(s):  
Sravani Bharandev ◽  
Sapar Narayan Rao
Keyword(s):  
Trading Volume ◽  
Stock Exchange ◽  
Reference Points ◽  
Disposition Effect ◽  
Content Type ◽  
Ex Post ◽  
Abnormal Trading Volume ◽  
The Difference ◽  
Trading Volumes ◽  
Indian Stock Market

Purpose The purpose of this paper is to test the disposition effect at market level and propose an appropriate reference point for testing disposition at market level. Design/methodology/approach This is an empirical study conducted on 500 index stocks of NSE500 (National Stock Exchange). Winning and losing days for each stock are calculated using 52-week high and low prices as reference points. To test disposition effect, abnormal trading volumes of stocks are regressed on their percentage of winning (losing) days. Further using ANOVA, the difference between mean of percentage of winning (losing) days of high abnormal trading volume deciles and low abnormal trading volume deciles is tested. Findings Results show that a stock’s abnormal trading volume is positively influenced by the percentage of winning days whereas percentage of losing days show no such effect. Findings are consistent even after controlling for volatility and liquidity. ANOVA results show the presence of high percentage of winning days in higher deciles of abnormal trading volumes and no such pattern in case of losing days confirms the presence of disposition effect. Further an ex post analysis indicates that disposition prone investors accumulate losses. Originality/value This is the first study, which proposes the use of 52-week high and low prices as reference points to test the market-level disposition effect. Findings of this study enhance the limited literature available on disposition effect in emerging markets by providing evidence from Indian stock markets.

scholarly journals hfqPlays Important Roles in Virulence and Stress Adaptation in Cronobacter sakazakii ATCC 29544

2015 ◽  
Vol 83 (5) ◽  
pp. 2089-2098 ◽  
Author(s):  
Seongok Kim ◽  
Hyelyeon Hwang ◽  
Kwang-Pyo Kim ◽  
Hyunjin Yoon ◽  
Dong-Hyun Kang ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Bacterial Species ◽  
Soft Agar ◽  
Host Cells ◽  
Neonatal Meningitis ◽  
Animal Cells ◽  
Content Type ◽  
Flagellar Biosynthesis

Cronobacterspp. are opportunistic pathogens that cause neonatal meningitis and sepsis with high mortality in neonates. Despite the peril associated withCronobacterinfection, the mechanisms of pathogenesis are still being unraveled. Hfq, which is known as an RNA chaperone, participates in the interaction with bacterial small RNAs (sRNAs) to regulate posttranscriptionally the expression of various genes. Recent studies have demonstrated that Hfq contributes to the pathogenesis of numerous species of bacteria, and its roles are varied between bacterial species. Here, we tried to elucidate the role of Hfq inC. sakazakiivirulence. In the absence ofhfq,C. sakazakiiwas highly attenuated in disseminationin vivo, showed defects in invasion (3-fold) into animal cells and survival (103-fold) within host cells, and exhibited low resistance to hydrogen peroxide (102-fold). Remarkably, the loss ofhfqled to hypermotility on soft agar, which is contrary to what has been observed in other pathogenic bacteria. The hyperflagellated bacteria were likely to be attributable to the increased transcription of genes associated with flagellar biosynthesis in a strain lackinghfq. Together, these data strongly suggest thathfqplays important roles in the virulence ofC. sakazakiiby participating in the regulation of multiple genes.

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