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Flagellar morphology AND bacteria

E Sabaneyeva, M Castelli, F Szokoli, K Benken, N Lebedeva, A Salvetti, M Schweikert, S Fokin, G Petroni
Newly isolated strains of the ciliate Paramecium calkinsi and their cytoplasmic bacterial endosymbionts were characterized by a multidisciplinary approach, including live observation, ultrastructural investigation, and molecular analysis. Despite morphological resemblance, the characterized P. calkinsi strains showed a significant molecular divergence compared to conspecifics, possibly hinting for a cryptic speciation. The endosymbionts were clearly found to be affiliated to the species "Candidatus Trichorickettsia mobilis" (Rickettsiales, Rickettsiaceae), currently encompassing only bacteria retrieved in an obligate intracellular association with other ciliates...
December 9, 2017: European Journal of Protistology
Fouad El Baidouri, Chris Venditti, Stuart Humphries
Functional morphological adaptation is an implicit assumption across many ecological studies. However, despite a few pioneering attempts to link bacterial form and function, functional morphology is largely unstudied in prokaryotes. One intriguing candidate for analysis is bacterial shape, as multiple lines of theory indicate that cell shape and motility should be strongly correlated. Here we present a large-scale use of modern phylogenetic comparative methods to explore this relationship across 325 species of the phylum Firmicutes...
November 21, 2016: Nature Ecology & Evolution
Michael W Harman, Alex E Hamby, Ross Boltyanskiy, Alexia A Belperron, Linda K Bockenstedt, Holger Kress, Eric R Dufresne, Charles W Wolgemuth
Borrelia burgdorferi, the spirochete that causes Lyme disease, is a tick-transmitted pathogen that requires motility to invade and colonize mammalian and tick hosts. These bacteria use a unique undulating flat-wave shape to penetrate and propel themselves through host tissues. Previous mathematical modeling has suggested that the morphology and motility of these spirochetes depends crucially on the flagellar/cell wall stiffness ratio. Here, we test this prediction using the antibiotic vancomycin to weaken the cell wall...
February 28, 2017: Biophysical Journal
Wei Chen, Yong-Mei Zhang, Christopher Davies
Penicillin-binding proteins (PBPs) function as transpeptidases, carboxypeptidases, or endopeptidases during peptidoglycan synthesis in bacteria. As the well-known drug targets for β-lactam antibiotics, the physiological functions of PBPs and whether they are essential for growth are of significant interest. The pathogen Pseudomonas aeruginosa poses a particular risk to immunocompromised and cystic fibrosis patients, and infections caused by this pathogen are difficult to treat due to antibiotic resistance...
January 2017: Antimicrobial Agents and Chemotherapy
Fumiaki Makino, Dakang Shen, Naoko Kajimura, Akihiro Kawamoto, Panayiota Pissaridou, Henry Oswin, Maria Pain, Isabel Murillo, Keiichi Namba, Ariel J Blocker
Type III secretion systems (T3SSs) are essential devices in the virulence of many Gram-negative bacterial pathogens. They mediate injection of protein effectors of virulence from bacteria into eukaryotic host cells to manipulate them during infection. T3SSs involved in virulence (vT3SSs) are evolutionarily related to bacterial flagellar protein export apparatuses (fT3SSs), which are essential for flagellar assembly and cell motility. The structure of the external and transmembrane parts of both fT3SS and vT3SS is increasingly well-defined...
September 30, 2016: Scientific Reports
Ki Hwan Moon, Xiaowei Zhao, Akarsh Manne, Juyu Wang, Zhou Yu, Jun Liu, Md A Motaleb
Borrelia burgdorferi, the causative agent of Lyme disease, is a highly motile spirochete, and motility, which is provided by its periplasmic flagella, is critical for every part of the spirochete's enzootic life cycle. Unlike externally flagellated bacteria, spirochetes possess a unique periplasmic flagellar structure called the collar. This spirochete-specific novel component is linked to the flagellar basal body; however, nothing is known about the proteins encoding the collar or their function in any spirochete...
October 2016: Molecular Microbiology
Elsio A Wunder, Cláudio P Figueira, Nadia Benaroudj, Bo Hu, Brian A Tong, Felipe Trajtenberg, Jun Liu, Mitermayer G Reis, Nyles W Charon, Alejandro Buschiazzo, Mathieu Picardeau, Albert I Ko
Leptospira are unique among bacteria based on their helical cell morphology with hook-shaped ends and the presence of periplasmic flagella (PF) with pronounced spontaneous supercoiling. The factors that provoke such supercoiling, as well as the role that PF coiling plays in generating the characteristic hook-end cell morphology and motility, have not been elucidated. We have now identified an abundant protein from the pathogen L. interrogans, exposed on the PF surface, and named it Flagellar-coiling protein A (FcpA)...
August 2016: Molecular Microbiology
Célia Fontana, Ambroise Lambert, Nadia Benaroudj, David Gasparini, Olivier Gorgette, Nathalie Cachet, Natalia Bomchil, Mathieu Picardeau
Pathogenic Leptospira strains are responsible for leptospirosis, a worldwide emerging zoonotic disease. These spirochetes are unique amongst bacteria because of their corkscrew-like cell morphology and their periplasmic flagella. Motility is reported as an important virulence determinant, probably favoring entry and dissemination of pathogenic Leptospira in the host. However, proteins constituting the periplasmic flagella and their role in cell shape, motility and virulence remain poorly described. In this study, we characterized a spontaneous L...
2016: PloS One
Charles W Wolgemuth
Bacterial pathogens are often classified by their toxicity and invasiveness. The invasiveness of a given bacterium is determined by how capable the bacterium is at invading a broad range of tissues in its host. Of mammalian pathogens, some of the most invasive come from a group of bacteria known as the spirochetes, which cause diseases, such as syphilis, Lyme disease, relapsing fever and leptospirosis. Most of the spirochetes are characterized by their distinct shapes and unique motility. They are long, thin bacteria that can be shaped like flat-waves, helices, or have more irregular morphologies...
October 2015: Seminars in Cell & Developmental Biology
Denis V Tikhonenkov, Jan Janouškovec, Patrick J Keeling, Alexander P Mylnikov
A small free-living freshwater bacteriotrophic flagellate Neobodo borokensis n. sp. was investigated by electron microscopy and analysis of its SSU ribosomal RNA gene. This protist has paraxonemal rods of typical bodonid structure in the flagella, mastigonemes on the proximal part of the posterior flagellum, two nearly parallel basal bodies, a compact kinetoplast, and discoid mitochondrial cristae. The flagellar pocket is supported by three microtubular roots (R1, R2 and R3) originating from the kinetosome...
March 2016: Journal of Eukaryotic Microbiology
Eva Nováková, Filip Husník, Eva Šochová, Václav Hypša
Symbiosis between insects and bacteria result in a variety of arrangements, genomic modifications, and metabolic interconnections. Here, we present genomic, phylogenetic, and morphological characteristics of a symbiotic system associated with Melophagus ovinus, a member of the blood-feeding family Hippoboscidae. The system comprises four unrelated bacteria representing different stages in symbiosis evolution, from typical obligate mutualists inhabiting bacteriomes to freely associated commensals and parasites...
September 2015: Applied and Environmental Microbiology
Tao Lin, Lihui Gao, Xiaowei Zhao, Jun Liu, Steven J Norris
UNLABELLED: The Lyme disease spirochete Borrelia burgdorferi migrates to distant sites in the tick vectors and mammalian hosts through robust motility and chemotaxis activities. FliH and FliI are two cytoplasmic proteins that play important roles in the type III secretion system (T3SS)-mediated export and assembly of flagellar structural proteins. However, detailed analyses of the roles of FliH and FliI in B. burgdorferi have not been reported. In this study, fliH and fliI transposon mutants were utilized to dissect the mechanism of the Borrelia type III secretion system...
May 12, 2015: MBio
Syed Z Sultan, Padmapriya Sekar, Xiaowei Zhao, Akarsh Manne, Jun Liu, R Mark Wooten, M A Motaleb
Borrelia burgdorferi must migrate within and between its arthropod and mammalian hosts in order to complete its natural enzootic cycle. During tick feeding, the spirochete transmits from the tick to the host dermis, eventually colonizing and persisting within multiple, distant tissues. This dissemination modality suggests that flagellar motor rotation and, by extension, motility are crucial for infection. We recently reported that a nonmotile flaB mutant that lacks periplasmic flagella is rod shaped and unable to infect mice by needle or tick bite...
May 2015: Infection and Immunity
Kara J Levinson, Magdia De Jesus, Nicholas J Mantis
2D6 is a dimeric monoclonal immunoglobulin A (IgA) specific for the nonreducing terminal residue of Ogawa O-polysaccharide (OPS) of Vibrio cholerae. It was previously demonstrated that 2D6 IgA is sufficient to passively protect suckling mice from oral challenge with virulent V. cholerae O395. In this study, we sought to define the mechanism by which 2D6 IgA antibody protects the intestinal epithelium from V. cholerae infection. In a mouse ligated-ileal-loop assay, 2D6 IgA promoted V. cholerae agglutination in the intestinal lumen and limited the ability of the bacteria to associate with the epithelium, particularly within the crypt regions...
April 2015: Infection and Immunity
Takashi Shiratori, Akiko Yokoyama, Ken-Ichiro Ishida
Abollifer is a little-known genus of marine heterotrophic flagellates with no ultrastructural and molecular information, and its taxonomic position remains uncertain. In this study, we report a new species of Abollifer, Abollifer globosa sp. nov., isolated from a seawater sample collected at Tokyo Bay. To reveal the taxonomic position and morphological characteristics of A. globosa, we performed light and electron microscopic observations and a phylogenetic analysis using small subunit ribosomal DNA sequences...
December 2014: Protist
Christopher T Lefèvre, Mathieu Bennet, Livnat Landau, Peter Vach, David Pignol, Dennis A Bazylinski, Richard B Frankel, Stefan Klumpp, Damien Faivre
Microorganisms living in gradient environments affect large-scale processes, including the cycling of elements such as carbon, nitrogen or sulfur, the rates and fate of primary production, and the generation of climatically active gases. Aerotaxis is a common adaptation in organisms living in the oxygen gradients of stratified environments. Magnetotactic bacteria are such gradient-inhabiting organisms that have a specific type of aerotaxis that allows them to compete at the oxic-anoxic interface. They biomineralize magnetosomes, intracellular membrane-coated magnetic nanoparticles, that comprise a permanent magnetic dipole that causes the cells to align along magnetic field lines...
July 15, 2014: Biophysical Journal
Claudia Vannini, Vittorio Boscaro, Filippo Ferrantini, Konstantin A Benken, Timofei I Mironov, Michael Schweikert, Hans-Dieter Görtz, Sergei I Fokin, Elena V Sabaneyeva, Giulio Petroni
Bacteria of the family Rickettsiaceae have always been largely studied not only for their importance in the medical field, but also as model systems in evolutionary biology. In fact, they share a recent common ancestor with mitochondria. The most studied species, belonging to genera Rickettsia and Orientia, are hosted by terrestrial arthropods and include many human pathogens. Nevertheless, recent findings show that a large part of Rickettsiaceae biodiversity actually resides outside the group of well-known pathogenic bacteria...
2014: PloS One
Shuichi Nakamura, Alexander Leshansky, Yukio Magariyama, Keiichi Namba, Seishi Kudo
Leptospira are spirochete bacteria distinguished by a short-pitch coiled body and intracellular flagella. Leptospira cells swim in liquid with an asymmetric morphology of the cell body; the anterior end has a long-pitch spiral shape (S-end) and the posterior end is hook-shaped (H-end). Although the S-end and the coiled cell body called the protoplasmic cylinder are thought to be responsible for propulsion together, most observations on the motion mechanism have remained qualitative. In this study, we analyzed the swimming speed and rotation rate of the S-end, protoplasmic cylinder, and H-end of individual Leptospira cells by one-sided dark-field microscopy...
January 7, 2014: Biophysical Journal
Cyril Guyard, Sandra J Raffel, Merry E Schrumpf, Eric Dahlstrom, Daniel Sturdevant, Stacy M Ricklefs, Craig Martens, Stanley F Hayes, Elizabeth R Fischer, Bryan T Hansen, Stephen F Porcella, Tom G Schwan
Spirochetes are bacteria characterized in part by rotating periplasmic flagella that impart their helical or flat-wave morphology and motility. While most other bacteria rely on a transcriptional cascade to regulate the expression of motility genes, spirochetes employ post-transcriptional mechanism(s) that are only partially known. In the present study, we characterize a spontaneous non-motile mutant of the relapsing fever spirochete Borrelia hermsii that was straight, non-motile and deficient in periplasmic flagella...
2013: PloS One
Jonathan D Partridge, Rasika M Harshey
Movement over an agar surface via swarming motility is subject to formidable challenges not encountered during swimming. Bacteria display a great deal of flexibility in coping with these challenges, which include attracting water to the surface, overcoming frictional forces, and reducing surface tension. Bacteria that swarm on "hard" agar surfaces (robust swarmers) display a hyperflagellated and hyperelongated morphology. Bacteria requiring a "softer" agar surface (temperate swarmers) do not exhibit such a dramatic morphology...
March 2013: Journal of Bacteriology
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