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Basic Microbiology
Published in Philip A. Geis, Cosmetic Microbiology, 2020
Flagella—These large proteinaceous machines are anchored to the bacterial membrane and cell wall structures and are “spun” to create swimming or swarming motility for those species that possess them. The flagella with its whip-like structure help motile bacteria to swim toward or away from certain substances by “chemotaxis”.
Pseudomonas
Published in Dongyou Liu, Handbook of Foodborne Diseases, 2018
Rajasekharan Sharika, Krishnaswamy Balamurugan
The genus Pseudomonas encompasses a number of species and strain variants, which demonstrate slightly curved or rod-shaped morphology, measure 0.5–1.0 μm in diameter with a maximum length of approximately 4 μm, and occur either as single cells or in groups as short chains. They are gram negative and motile and possess polar flagella that help in chemosensory movement. In some cases, more than one flagellum are present. The presence of pili plays a major role in pathogenesis, which has been studied in clinically important species of Pseudomonas.24,25 The presence of lateral flagella has also been observed in some species of Pseudomonas, which help in swarming motility.5,26Pseudomonas grow well at 37°C, although they can also thrive in a temperature range of 4°C–42°C under laboratory conditions along with parameters such as neutral pH, good aeration, and media containing organic compounds.3,27
Proteus
Published in Dongyou Liu, Laboratory Models for Foodborne Infections, 2017
Paola Scavone, Victoria Iribarnegaray, Pablo Zunino
Flagella-mediated motility is related to P. mirabilis swarming motility. This behavior is based on sequential rounds of swarm cell differentiation, swarming colony migration, and consolidation with dedifferentiation to a swimmer-cell morphology [23]. Swarmer cells are multinucleate, are elongated (more than 10 μm long), and express several flagella, while swimmer cells are rod shaped, are 1–2 μm long, and have peritrichous flagella [23]. Several studies have revealed a complex regulatory network during swarm cell differentiation. There is a reciprocal regulation between fimbrial and flagella expression. There are 14 additional mrpJ paralogs associated with other fimbrial operons [23,24], and most of them repress motility, inhibiting swarm cell differentiation [24]. Bacteria adopt a filamentous morphology as a result of the sensor activities of flagella in contact, for example, with a urinary catheter. Contact to solid surfaces creates a torsional change in the outer membrane, and this is sensed by an upregulator of the flagellar master operon (Umo) protein, which induces the expression of flagella to produce the highly flagellated cells that are required for swarming [11]. This motility is related with migration across different abiotic surfaces including catheters.
Subtle relationships between Pseudomonas aeruginosa and fungi in patients with cystic fibrosis
Published in Acta Clinica Belgica, 2022
Kaicheng Yan, Hong Yin, Jin Wang, Yun Cai
In CA, farnesol (sesquiterpene derivative) and tyrosol (tyrosine derivative) are identified as the main QS compounds in the pathogenic yeast [71,72]. Farnesol is a metabolite of the mevalonate/sterol pathway in eukaryotes, which is produced in situ by planktonic CA cultures [73]. Cugini et al. have found that the addition of farnesol to cultures of PA leads to decreased production of PQS and the PQS-controlled virulence factor, pyocyanin [74]. McAlester et al. have shown that farnesol also reduces the ability to swarm the motility of PA [75]. Swarming motility is one of the movement forms of PA, which is closely related to the pathogenicity of PA. Additionally, tyrosol can affect the antibiotic sensitivity and production of the virulence factors, hemolysin, and total proteasest, which is considered to be an important virulence factor of PA [76]. Tyrosol can significantly inhibit the PA production of protease, while farnesol does not show such an effect
Inhibitory effect of norharmane on Serratia marcescens NJ01 quorum sensing-mediated virulence factors and biofilm formation
Published in Biofouling, 2021
Huai-Zhi Luo, Jin-Wei Zhou, Bing Sun, Huan Jiang, Shi Tang, Ai-Qun Jia
S. marcescens produces multiple QS-related virulence factors, such as prodigiosin, hemolysin, protease, lipase and swarming motility. Prodigiosin, participates in host invasion, while hemolysin has the ability to lyse the red blood cells (Coulthurst et al. 2006). The production of both of these compounds was significantly suppressed and in accordance with the down-regulation of the transcriptional level of genes pigA, pigC and shlA. Norharmane could inhibit extracellular protease and lipase production by S. marcescens NJ01, which play key roles in host infection and cytolytic activities respectively (Kida et al. 2007). Swarming plays an important role in colonization, which also includes the other two stages: initial attachment and biofilm formation (Rasmussen et al. 2000). Swarming motility mediated by flagella is regulated by flhD and conducive to biofilm formation by enhancing cell surface attachment (Fekrirad et al. 2019). In addition, the genes fimA and fimC are the major fimbriae subunits, significant for adhesin attachment and colonization by S. marcescens (Srinivasan et al. 2018). The genes bsmA and bsmB regulate biofilm formation in S. marcescens, and biofilm formation was a failure with mutation of these genes (Labbate et al. 2004). Here, exposure to norharmane, and the down-regulation of genes fimA, fimC, bsmA, bsmB and flhD were responsible for the reduction in the attachment capacity, biofilm formation, swarming motility.
Novel thiazolinyl-picolinamide based palladium(II) complex-impregnated urinary catheters quench the virulence and disintegrate the biofilms of uropathogens
Published in Biofouling, 2020
Deeksha Rajkumar, Durairajan Rubini, M. Sudharsan, D. Suresh, Paramasivam Nithyanand
Swarming motility plays a significant role in the formation and movement of uniform biofilms. The ability of the palladium(II) complexes (c and f) to inhibit QS-mediated swarming motility in P. aeruginosa and S. marcescens was assessed by the soft agar method. In brief, soft agar for P. aeruginosa was prepared for 25 ml using 0.5% agar, 5% glucose, 0.5% peptone, 0.2% yeast extract, and for S. marcescens soft agar was prepared for 25 ml using 1% Tryptone, 0.5% Nacl and 0.5% agar. 5 µl of P. aeruginosa were spotted on swarming soft agar plates overlaid in the presence of the palladium(II) complexes (c and f), and incubated at 37° C for 24 h. The same assay was carried out for S. marcescens with soft agar. 5 µl of S. marcescens was spotted and incubated at 28° C for 24 h and observed for swarming motility inhibition.