scholarly journals The Vibrio H-ring facilitates the outer membrane penetration of polar-sheathed flagellum

2018 ◽  
Author(s):  
Shiwei Zhu ◽  
Tatsuro Nishikino ◽  
Seiji Kojima ◽  
Michio Homma ◽  
Jun Liu
Keyword(s):  
Outer Membrane ◽  
Electron Tomography ◽  
Bacterial Species ◽  
Vibrio Alginolyticus ◽  
Unexpected Finding ◽  
New Paradigm ◽  
Bacterial Flagellum ◽  
Periplasmic Flagella ◽  
Flagella Assembly ◽  
First Time

AbstractThe bacterial flagellum has evolved as one of the most remarkable nanomachines in nature. It provides swimming and swarming motilities that are often essential for the bacterial life cycle and for pathogenesis. Many bacteria such as Salmonella and Vibrio species use flagella as an external propeller to move to favorable environments, while spirochetes utilize internal periplasmic flagella to drive a serpentine movement of the cell bodies through tissues. Here we use cryo-electron tomography to visualize the polar-sheathed flagellum of Vibrio alginolyticus with particular focus on a Vibrio specific feature, the H-ring. We characterized the H-ring by identifying its two components FlgT and FlgO. Surprisingly, we discovered that the majority of flagella are located within the periplasmic space in the absence of the H-ring, which are dramatically different from external flagella in wild-type cells. Our results indicate the H-ring has a novel function in facilitating the penetration of the outer membrane and the assembly of the external sheathed flagella. This unexpected finding is however consistent with the notion that the flagella have evolved to adapt highly diverse needs by receiving or removing accessary genes.Significance StatementFlagellum is the major organelle for motility in many bacterial species. While most bacteria possess external flagella such as the multiple peritrichous flagella found in Escherichia coli and Salmonella enterica or the single polar-sheathed flagellum in Vibrio spp., spirochetes uniquely assemble periplasmic flagella, which are embedded between their inner and outer membranes. Here, we show for the first time that the external flagella in Vibrio alginolyticus can be changed as periplasmic flagella by deleting two flagellar genes. The discovery here may provide a new paradigm to understand the molecular basis underlying flagella assembly, diversity, and evolution.

scholarly journals The Vibrio H-Ring Facilitates the Outer Membrane Penetration of the Polar Sheathed Flagellum

2018 ◽  
Vol 200 (21) ◽  
Author(s):  
Shiwei Zhu ◽  
Tatsuro Nishikino ◽  
Seiji Kojima ◽  
Michio Homma ◽  
Jun Liu
Keyword(s):  
Outer Membrane ◽  
Electron Tomography ◽  
Bacterial Species ◽  
Vibrio Alginolyticus ◽  
Content Type ◽  
Bacterial Flagellum ◽  
Outer Membranes ◽  
Cryo Electron Tomography ◽  
Periplasmic Flagella ◽  
First Time

ABSTRACT The bacterial flagellum has evolved as one of the most remarkable nanomachines in nature. It provides swimming and swarming motilities that are often essential for the bacterial life cycle and pathogenesis. Many bacteria such as Salmonella and Vibrio species use flagella as an external propeller to move to favorable environments, whereas spirochetes utilize internal periplasmic flagella to drive a serpentine movement of the cell bodies through tissues. Here, we use cryo-electron tomography to visualize the polar sheathed flagellum of Vibrio alginolyticus with particular focus on a Vibrio-specific feature, the H-ring. We characterized the H-ring by identifying its two components FlgT and FlgO. We found that the majority of flagella are located within the periplasmic space in the absence of the H-ring, which are different from those of external flagella in wild-type cells. Our results not only indicate the H-ring has a novel function in facilitating the penetration of the outer membrane and the assembly of the external sheathed flagella but also are consistent with the notion that the flagella have evolved to adapt highly diverse needs by receiving or removing accessary genes. IMPORTANCE Flagellum is the major organelle for motility in many bacterial species. While most bacteria possess external flagella, such as the multiple peritrichous flagella found in Escherichia coli and Salmonella enterica or the single polar sheathed flagellum in Vibrio spp., spirochetes uniquely assemble periplasmic flagella, which are embedded between their inner and outer membranes. Here, we show for the first time that the external flagella in Vibrio alginolyticus can be changed as periplasmic flagella by deleting two flagellar genes. The discovery here may provide new insights into the molecular basis underlying assembly, diversity, and evolution of flagella.

scholarly journals Bacterial flagellar motor PL-ring disassembly subcomplexes are widespread and ancient

2020 ◽  
Vol 117 (16) ◽  
pp. 8941-8947 ◽  
Author(s):  
Mohammed Kaplan ◽  
Michael J. Sweredoski ◽  
João P. G. L. M. Rodrigues ◽  
Elitza I. Tocheva ◽  
Yi-Wei Chang ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Electron Tomography ◽  
Complex Structures ◽  
Flagellar Motor ◽  
Additional Species ◽  
Bacterial Flagellum ◽  
Cryo Electron Tomography ◽  
Show Evidence ◽  
Bacterial Flagellar Motor ◽  
Horizontal Transfers

The bacterial flagellum is an amazing nanomachine. Understanding how such complex structures arose is crucial to our understanding of cellular evolution. We and others recently reported that in several Gammaproteobacterial species, a relic subcomplex comprising the decorated P and L rings persists in the outer membrane after flagellum disassembly. Imaging nine additional species with cryo-electron tomography, here, we show that this subcomplex persists after flagellum disassembly in other phyla as well. Bioinformatic analyses fail to show evidence of any recent horizontal transfers of the P- and L-ring genes, suggesting that this subcomplex and its persistence is an ancient and conserved feature of the flagellar motor. We hypothesize that one function of the P and L rings is to seal the outer membrane after motor disassembly.

scholarly journals Phylogenetic Distribution, Ultrastructure, and Function of Bacterial Flagellar Sheaths

Biomolecules ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 363 ◽  
Author(s):  
Joshua Chu ◽  
Jun Liu ◽  
Timothy R. Hoover
Keyword(s):  
Immune Response ◽  
Outer Membrane ◽  
Electron Tomography ◽  
Bacterial Species ◽  
Outer Membrane Proteins ◽  
Wall Layer ◽  
Host Cells ◽  
Outer Cell ◽  
Flagellar Filament ◽  
And Function

A number of Gram-negative bacteria have a membrane surrounding their flagella, referred to as the flagellar sheath, which is continuous with the outer membrane. The flagellar sheath was initially described in Vibrio metschnikovii in the early 1950s as an extension of the outer cell wall layer that completely surrounded the flagellar filament. Subsequent studies identified other bacteria that possess flagellar sheaths, most of which are restricted to a few genera of the phylum Proteobacteria. Biochemical analysis of the flagellar sheaths from a few bacterial species revealed the presence of lipopolysaccharide, phospholipids, and outer membrane proteins in the sheath. Some proteins localize preferentially to the flagellar sheath, indicating mechanisms exist for protein partitioning to the sheath. Recent cryo-electron tomography studies have yielded high resolution images of the flagellar sheath and other structures closely associated with the sheath, which has generated insights and new hypotheses for how the flagellar sheath is synthesized. Various functions have been proposed for the flagellar sheath, including preventing disassociation of the flagellin subunits in the presence of gastric acid, avoiding activation of the host innate immune response by flagellin, activating the host immune response, adherence to host cells, and protecting the bacterium from bacteriophages.

scholarly journals The Conservation of Low Complexity Regions in Bacterial Proteins Depends on the Pathogenicity of the Strain and Subcellular Location of the Protein

Genes ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 451
Author(s):  
Pablo Mier ◽  
Miguel A. Andrade-Navarro
Keyword(s):  
Membrane Proteins ◽  
Outer Membrane ◽  
Bacterial Species ◽  
Outer Membrane Proteins ◽  
Subcellular Location ◽  
Low Complexity ◽  
Extracellular Proteins ◽  
Bacterial Strains ◽  
Bacterial Proteins ◽  
Protein Subcellular Location

Low complexity regions (LCRs) in proteins are characterized by amino acid frequencies that differ from the average. These regions evolve faster and tend to be less conserved between homologs than globular domains. They are not common in bacteria, as compared to their prevalence in eukaryotes. Studying their conservation could help provide hypotheses about their function. To obtain the appropriate evolutionary focus for this rapidly evolving feature, here we study the conservation of LCRs in bacterial strains and compare their high variability to the closeness of the strains. For this, we selected 20 taxonomically diverse bacterial species and obtained the completely sequenced proteomes of two strains per species. We calculated all orthologous pairs for each of the 20 strain pairs. Per orthologous pair, we computed the conservation of two types of LCRs: compositionally biased regions (CBRs) and homorepeats (polyX). Our results show that, in bacteria, Q-rich CBRs are the most conserved, while A-rich CBRs and polyA are the most variable. LCRs have generally higher conservation when comparing pathogenic strains. However, this result depends on protein subcellular location: LCRs accumulate in extracellular and outer membrane proteins, with conservation increased in the extracellular proteins of pathogens, and decreased for polyX in the outer membrane proteins of pathogens. We conclude that these dependencies support the functional importance of LCRs in host–pathogen interactions.

Continuous Ketone Monitoring: A New Paradigm for Physiologic Monitoring

2021 ◽  
pp. 193229682110098
Author(s):  
Jennifer Y. Zhang ◽  
Trisha Shang ◽  
Suneil K. Koliwad ◽  
David C. Klonoff
Keyword(s):  
Interstitial Fluid ◽  
Good Accuracy ◽  
Physiologic Monitoring ◽  
New Paradigm ◽  
Continuous Glucose Monitor ◽  
Sensor Platform ◽  
Wired Enzyme ◽  
First Time

In this issue of JDST, Alva and colleagues present for the first time, development of a continuous ketone monitor (CKM) tested both in vitro and in humans. Their sensor measured betahydroxybutyrate (BHB) in interstitial fluid (ISF). The sensor was based on wired enzyme electrochemistry technology using BHB dehydrogenase. The sensor required only a single retrospective calibration without a need for further adjustments over 14 days. The device produced a linear response over the 0-8 mM range with good accuracy. This novel CKM could provide a new dimension of useful automatically collected information for managing diabetes. Passively collected ISF ketone information would be useful for predicting and managing ketoacidosis in patients with type 1 diabetes, as well as other states of abnormal ketonemia. Although additional studies of this CKM will be required to assess performance in intended patient populations and prospective factory calibration will be required to support real time measurements, this novel monitor has the potential to greatly improve outcomes for people with diabetes. In the future, a CKM might be integrated with a continuous glucose monitor in the same sensor platform.

scholarly journals Temporal Stability and Biodiversity of Two Complex Antilisterial Cheese-Ripening Microbial Consortia

2003 ◽  
Vol 69 (7) ◽  
pp. 4012-4018 ◽  
Author(s):  
Ariel Maoz ◽  
Ralf Mayr ◽  
Siegfried Scherer
Keyword(s):  
Species Composition ◽  
Bacterial Species ◽  
Temporal Stability ◽  
Individual Characteristics ◽  
Microbial Consortia ◽  
Cheese Ripening ◽  
Safe Food ◽  
The Stability ◽  
The Individual ◽  
First Time

ABSTRACT The temporal stability and diversity of bacterial species composition as well as the antilisterial potential of two different, complex, and undefined microbial consortia from red-smear soft cheeses were investigated. Samples were collected twice, at 6-month intervals, from each of two food producers, and a total of 400 bacterial isolates were identified by Fourier-transform infrared spectroscopy and 16S ribosomal DNA sequence analysis. Coryneform bacteria represented the majority of the isolates, with certain species being predominant. In addition, Marinolactobacillus psychrotolerans, Halomonas venusta, Halomonas variabilis, Halomonas sp. (106 to 107 CFU per g of smear), and an unknown, gram-positive bacterium (107 to 108 CFU per g of smear) are described for the first time in such a consortium. The species composition of one consortium was quite stable over 6 months, but the other consortium revealed less diversity of coryneform species as well as less stability. While the first consortium had a stable, extraordinarily high antilisterial potential in situ, the antilisterial activity of the second consortium was lower and decreased with time. The cause for the antilisterial activity of the two consortia remained unknown but is not due to the secretion of soluble, inhibitory substances by the individual components of the consortium. Our data indicate that the stability over time and a potential antilisterial activity are individual characteristics of the ripening consortia which can be monitored and used for safe food production without artificial preservatives.

scholarly journals Shadowing the Actions of a Predator: Backlit Fluorescent Microscopy Reveals Synchronous Nonbinary Septation of Predatory Bdellovibrio inside Prey and Exit through Discrete Bdelloplast Pores

2010 ◽  
Vol 192 (24) ◽  
pp. 6329-6335 ◽  
Author(s):  
A. K. Fenton ◽  
M. Kanna ◽  
R. D. Woods ◽  
S.-I. Aizawa ◽  
R. E. Sockett
Keyword(s):  
Cell Division ◽  
Outer Membrane ◽  
Fluorescent Microscopy ◽  
Gram Negative Bacteria ◽  
Bacterial Cell Division ◽  
Prey Cell ◽  
Gram Negative ◽  
A Genome ◽  
Predatory Bacteria ◽  
First Time

ABSTRACT The Bdellovibrio are miniature “living antibiotic” predatory bacteria which invade, reseal, and digest other larger Gram-negative bacteria, including pathogens. Nutrients for the replication of Bdellovibrio bacteria come entirely from the digestion of the single invaded bacterium, now called a bdelloplast, which is bound by the original prey outer membrane. Bdellovibrio bacteria are efficient digesters of prey cells, yielding on average 4 to 6 progeny from digestion of a single prey cell of a genome size similar to that of the Bdellovibrio cell itself. The developmental intrabacterial cycle of Bdellovibrio is largely unknown and has never been visualized “live.” Using the latest motorized xy stage with a very defined z-axis control and engineered periplasmically fluorescent prey allows, for the first time, accurate return and visualization without prey bleaching of developing Bdellovibrio cells using solely the inner resources of a prey cell over several hours. We show that Bdellovibrio bacteria do not follow the familiar pattern of bacterial cell division by binary fission. Instead, they septate synchronously to produce both odd and even numbers of progeny, even when two separate Bdellovibrio cells have invaded and develop within a single prey bacterium, producing two different amounts of progeny. Evolution of this novel septation pattern, allowing odd progeny yields, allows optimal use of the finite prey cell resources to produce maximal replicated, predatory bacteria. When replication is complete, Bdellovibrio cells exit the exhausted prey and are seen leaving via discrete pores rather than by breakdown of the entire outer membrane of the prey.

scholarly journals Bacterial Flagellar Filament: A Supramolecular Multifunctional Nanostructure

2021 ◽  
Vol 22 (14) ◽  
pp. 7521
Author(s):  
Marko Nedeljković ◽  
Diego Emiliano Sastre ◽  
Eric John Sundberg
Keyword(s):  
Immune Responses ◽  
Basal Body ◽  
Vaccine Development ◽  
Bacterial Species ◽  
High Variability ◽  
Bacterial Survival ◽  
Bacterial Flagellum ◽  
Capping Proteins ◽  
Flagellar Filament ◽  
Flagellar Assembly

The bacterial flagellum is a complex and dynamic nanomachine that propels bacteria through liquids. It consists of a basal body, a hook, and a long filament. The flagellar filament is composed of thousands of copies of the protein flagellin (FliC) arranged helically and ending with a filament cap composed of an oligomer of the protein FliD. The overall structure of the filament core is preserved across bacterial species, while the outer domains exhibit high variability, and in some cases are even completely absent. Flagellar assembly is a complex and energetically costly process triggered by environmental stimuli and, accordingly, highly regulated on transcriptional, translational and post-translational levels. Apart from its role in locomotion, the filament is critically important in several other aspects of bacterial survival, reproduction and pathogenicity, such as adhesion to surfaces, secretion of virulence factors and formation of biofilms. Additionally, due to its ability to provoke potent immune responses, flagellins have a role as adjuvants in vaccine development. In this review, we summarize the latest knowledge on the structure of flagellins, capping proteins and filaments, as well as their regulation and role during the colonization and infection of the host.

scholarly journals The Diversity of Bacteria Associated with the Invasive Gall Wasp Dryocosmus kuriphilus, Its Galls and a Specialist Parasitoid on Chestnuts

Insects ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 86
Author(s):  
Xiaohui Yang ◽  
Yu Hui ◽  
Daohong Zhu ◽  
Yang Zeng ◽  
Lvquan Zhao ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Plant Pathogens ◽  
High Throughput Sequencing ◽  
Bacterial Species ◽  
Gall Wasp ◽  
Potential Vector ◽  
Dryocosmus Kuriphilus ◽  
Torymus Sinensis ◽  
Galling Insects ◽  
First Time

Dryocosmus kuriphilus (Hymenoptera: Cynipidae) induces galls on chestnut trees, which results in massive yield losses worldwide. Torymus sinensis (Hymenoptera: Torymidae) is a host-specific parasitoid that phenologically synchronizes with D. kuriphilus. Bacteria play important roles in the life cycle of galling insects. The aim of this research is to investigate the bacterial communities and predominant bacteria of D. kuriphilus, T. sinensis, D. kuriphilus galls and the galled twigs of Castanea mollissima. We sequenced the V5–V7 region of the bacterial 16S ribosomal RNA in D. kuriphilus, T. sinensis, D. kuriphilus galls and galled twigs using high-throughput sequencing for the first time. We provide the first evidence that D. kuriphilus shares most bacterial species with T. sinensis, D. kuriphilus galls and galled twigs. The predominant bacteria of D. kuriphilus are Serratia sp. and Pseudomonas sp. Furthermore, the bacterial community structures of D. kuriphilus and T. sinensis clearly differ from those of the other groups. Many species of the Serratia and Pseudomonas genera are plant pathogenic bacteria, and we suggest that D. kuriphilus may be a potential vector of plant pathogens. Furthermore, a total of 111 bacteria are common to D. kuriphilus adults, T. sinensis, D. kuriphilus galls and galled twigs, and we suggest that the bacteria may transmit horizontally among D. kuriphilus, T. sinensis, D. kuriphilus galls and galled twigs on the basis of their ecological associations.

scholarly journals Probiotic Potential of Indigenous (Bacillus sp. RCS1, Pantoea agglomerans RCS2, and Bacillus cereus strain RCS3) Isolated From Cobia Fish (Rachycentron canadum) and Their Antagonistic Effects on the Growth of Pathogenic Vibrio alginolyticus, Vibrio harveyi, Streptococcus iniae, and Streptococcus agalactiae

2021 ◽  
Vol 8 ◽  
Author(s):  
Eric Amenyogbe ◽  
Jian-sheng Huang ◽  
Gang Chen ◽  
Wei-zheng Wang
Keyword(s):  
Bacillus Cereus ◽  
Streptococcus Agalactiae ◽  
Vibrio Harveyi ◽  
Bacterial Species ◽  
Vibrio Alginolyticus ◽  
Pantoea Agglomerans ◽  
Streptococcus Iniae ◽  
Rachycentron Canadum ◽  
Antagonistic Effects ◽  
Wide Range

Large-scale fish farming faces many environmental stresses, which affect their immune systems, growth performance, and physiological homeostasis, resulting in increase in their susceptibility to infections. Some of the most common bacterial infections of cobia fish (Rachycentron canadum) include streptococcosis, vibriosis, furunculosis and mycobacteriosis, and pastelleurosis. Probiotics could be helpful in reducing or limiting the incidence of severe disease infections or outbreaks. Therefore, the present study aimed to isolate the indigenous bacterial species from healthy cobia fish and then selected 3 strains, including Bacillus sp. RCS1 (MW560712), Pantoea agglomerans RCS2 (MW560713), and Bacillus cereus RCS3 (MW560714) from the gut of juvenile’s cobia having advantageous assets or positive characteristics. Their analysis indicated the presence of similar biochemical profiles and all could effectively utilize carbon sources. The biosafety assessment did not show any pathological symptoms after 10 days of injecting the fish with isolated bacteria. The results showed that all the isolated bacteria in the present study had low auto-aggregation capacity within the first 3 h of incubation. The isolated bacteria showed strong tolerance when exposed to a range of pH. Although asymmetrically, a slow rise in the growth of isolated bacteria was observed within the pH range of 1–8 for RC1, 1–7 for RC2, and 1–6 for RC3. The antagonistic effects of isolated bacterial strains on the development of pathogens, including Vibrio alginolyticus, Vibrio harveyi, Streptococcus iniae, and Streptococcus agalactiae, were investigated using Luria-Bertani (LB) agar plates. All the isolated bacteria exhibited inhibitory effects against the pathogens, including V. alginolyticus, V. harveyi, S. iniae, and S. agalactiae. These isolated bacteria were characterized with a wide range of antagonistic activities, non-hemolytic activities, high survivability after heat-treatments and safety confidence, and antibiotic susceptibility. Generally, the characteristics displayed by these strains indicated that they could be used as potential probiotics in the aquaculture industry.

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