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Sonja-Verena Albers, Ken F Jarrell
Each of the three domains of life exhibits a unique motility structure: while Bacteria use flagella, Eukarya employ cilia, and Archaea swim using archaella. Since the new name for the archaeal motility structure was proposed, in 2012, a significant amount of new data on the regulation of transcription of archaella operons, the structure and function of archaellum subunits, their interactions, and cryo-EM data on in situ archaellum complexes in whole cells have been obtained. These data support the notion that the archaellum is evolutionary and structurally unrelated to the flagellum, but instead is related to archaeal and bacterial type IV pili and emphasize that it is a motility structure unique to the Archaea...
February 13, 2018: Trends in Microbiology
Charles Coutton, Alexandra S Vargas, Amir Amiri-Yekta, Zine-Eddine Kherraf, Selima Fourati Ben Mustapha, Pauline Le Tanno, Clémentine Wambergue-Legrand, Thomas Karaouzène, Guillaume Martinez, Serge Crouzy, Abbas Daneshipour, Seyedeh Hanieh Hosseini, Valérie Mitchell, Lazhar Halouani, Ouafi Marrakchi, Mounir Makni, Habib Latrous, Mahmoud Kharouf, Jean-François Deleuze, Anne Boland, Sylviane Hennebicq, Véronique Satre, Pierre-Simon Jouk, Nicolas Thierry-Mieg, Beatrice Conne, Denis Dacheux, Nicolas Landrein, Alain Schmitt, Laurence Stouvenel, Patrick Lorès, Elma El Khouri, Serge P Bottari, Julien Fauré, Jean-Philippe Wolf, Karin Pernet-Gallay, Jessica Escoffier, Hamid Gourabi, Derrick R Robinson, Serge Nef, Emmanuel Dulioust, Raoudha Zouari, Mélanie Bonhivers, Aminata Touré, Christophe Arnoult, Pierre F Ray
Spermatogenesis defects concern millions of men worldwide, yet the vast majority remains undiagnosed. Here we report men with primary infertility due to multiple morphological abnormalities of the sperm flagella with severe disorganization of the sperm axoneme, a microtubule-based structure highly conserved throughout evolution. Whole-exome sequencing was performed on 78 patients allowing the identification of 22 men with bi-allelic mutations in DNAH1 (n = 6), CFAP43 (n = 10), and CFAP44 (n = 6). CRISPR/Cas9 created homozygous CFAP43/44 male mice that were infertile and presented severe flagellar defects confirming the human genetic results...
February 15, 2018: Nature Communications
Swayamshree Patra, Debashish Chowdhury
We introduce a multispecies exclusion model where length-conserving probabilistic fusion and fission of the hard rods are allowed. Although all rods enter the system with the same initial length ℓ=1, their length can keep changing, because of fusion and fission, as they move in a step-by-step manner towards the exit. Two neighboring hard rods of lengths ℓ_{1} and ℓ_{2} can fuse into a single rod of longer length ℓ=ℓ_{1}+ℓ_{2} provided ℓ≤N. Similarly, length-conserving fission of a rod of length ℓ^{'}≤N results in two shorter daughter rods...
January 2018: Physical Review. E
Renfei Lu, George Osei-Adjei, Xinxiang Huang, Yiquan Zhang
Quorum sensing (QS), a cell-to-cell communication process, is widely distributed in the bacterial kingdom. Bacteria use QS to control gene expression in response to cell density by detecting the signal molecules called autoinducers. AphA protein is the master QS regulator of vibrios operating at low cell density. It regulates the expression of a variety of genes, especially those encoding virulence factors, flagella/motility and biofilm formation. The role and regulation of AphA in vibrios, especially in human pathogenic vibrios, are summarized in this review...
February 14, 2018: Future Microbiology
Larissa M Dias, Adriana R C Folador, Amanda M Oliveira, Rommel T J Ramos, Artur Silva, Rafael A Baraúna
Exiguobacterium and Psychrobacter are bacterial genera with several cold-adapted species. These extremophiles are commonly isolated from the same habitats in Earth's cryosphere and have great ecological and biotechnological relevance. Thus, through comparative genomic analyses, it was possible to understand the functional diversity of these psychrotrophic and psychrophilic species and present new insights into the microbial adaptation to cold. The nucleotide identity between Exiguobacterium genomes was higher than 90%...
February 8, 2018: Genome Biology and Evolution
Jean-Lou Justine, Larisa G Poddubnaya
Sperm ultrastructure provides morphological characters useful for understanding phylogeny; no study was available for two basal branches of the Polyopisthocotylea, the Chimaericolidea and Diclybothriidea. We describe here spermiogenesis and sperm in Chimaericola leptogaster (Chimaericolidae) and Rajonchocotyle emarginata (Hexabothriidae), and sperm in Callorhynchocotyle callorhynchi (Hexabothriidae). Spermiogenesis in C. leptogaster and R. emarginata shows the usual pattern of most Polyopisthocotylea with typical zones of differentiation and proximo-distal fusion of the flagella...
2018: Parasite: Journal de la Société Française de Parasitologie
Yi-Ling Lo, Chyi-Liang Chen, Lunda Shen, Ying-Ching Chen, Yi-Hsin Wang, Chung-Chan Lee, Lian-Chen Wang, Chih-Hsien Chuang, Rajendra Prasad Janapatla, Cheng-Hsun Chiu, Hwan-You Chang
FliA is known to be a sigma factor that regulates bacterial flagella gene expression. Accumulating evidence suggests that FliA is involved in bacterial behavior other than motility. To elucidate the contribution of FliA to Pseudomonas aeruginosa pathophysiology, we analyzed the biological properties and gene expression profiles of a ΔfliA mutant. Transcriptome analysis results demonstrated that the expression levels of flagella biogenesis genes decreased dramatically in the mutant; consequently, the ΔfliA mutant failed to synthesize flagella and exhibited reduced motility...
February 9, 2018: Research in Microbiology
Muneyoshi Ichikawa, Khanh Huy Bui
Motile eukaryotic cilia and flagella are hair-like organelles responsible for cell motility and mucociliary clearance. Using cryo-electron tomography, it has been shown that the doublet microtubule, the cytoskeleton core of the cilia and flagella, has microtubule inner protein structures binding periodically inside its lumen. More recently, single-particle cryo-electron microscopy analyses of isolated doublet microtubules have shown that microtubule inner proteins form a meshwork inside the doublet microtubule...
February 12, 2018: BioEssays: News and Reviews in Molecular, Cellular and Developmental Biology
Justas Dauparas, Debasish Das, Eric Lauga
Recent experiments proposed to use confined bacteria in order to generate flows near surfaces. We develop a mathematical and a computational model of this fluid transport using a linear superposition of fundamental flow singularities. The rotation of a helical bacterial flagellum induces both a force and a torque on the surrounding fluid, both of which lead to a net flow along the surface. The combined flow is in general directed at an angle to the axis of the flagellar filament. The optimal pumping is thus achieved when bacteria are tilted with respect to the direction in which one wants to move the fluid, in good agreement with experimental results...
January 2018: Biomicrofluidics
Linda Turner, Howard C Berg
We describe labeling of bacteria with amino-specific or sulfhydryl-specific Alexa Fluor dyes, methods that allow visualization of flagellar filaments, even in swimming cells. Bacterial flagellar filaments are long (~10 μm), but of small diameter (~20 nm), and their rotation rates are high (>100 Hz), so visualization is difficult. Dark-field microscopy works well with isolated filaments, but visualization in situ is hampered by light scattered from cell bodies, which obscures short filaments or the proximal ends of long filaments...
2018: Methods in Molecular Biology
Anne E Mattingly, Nachiket Kamatkar, Bradley R Borlee, Joshua D Shrout
Pseudomonas aeruginosa exhibits flagellar-mediated swimming in liquid and swarming on hydrated surfaces under diverse nutrient conditions. Prior studies have implicated a phosphodiesterase, DipA, in regulating these flagella-mediated motilities, but collectively, the necessity for DipA was unclear. In this study, we find that the media composition conditionally constrains the influence of DipA on flagellar motility. We show that DipA exhibits more influence on minimal media supplemented with glutamate or glucose where flagellar motility was negated for the dipA mutant...
February 2, 2018: Applied and Environmental Microbiology
Davide Zabeo, John M Heumann, Cindi L Schwartz, Azusa Suzuki-Shinjo, Garry Morgan, Per O Widlund, Johanna L Höög
Eukaryotic flagella are complex cellular extensions involved in many human diseases gathered under the term ciliopathies. Currently, detailed insights on flagellar structure come mostly from studies on protists. Here, cryo-electron tomography (cryo-ET) was performed on intact human spermatozoon tails and showed a variable number of microtubules in the singlet region (inside the end-piece). Inside the microtubule plus end, a novel left-handed interrupted helix which extends several micrometers was discovered...
February 9, 2018: Scientific Reports
Zhihong Xie, Wei Liu, Yu Sun, Rimin Shen, Xiaoxiao Dang, Xiaolin Liu, Fu Sui, Yan Li, Zhenpeng Zhang, Gladys Alexandre, Claudine Elmerich
The genome of the Azorhizobium caulinodans ORS571 contains a unique chemotaxis gene cluster (che) including 5 chemotaxis genes: cheAWY1BR. Analysis of the role of the chemotaxis cluster of A. caulinodans, using deletion mutant strains revealed that CheA or Che signaling pathway controls chemotaxis behavior and flagella-driven motility, and plays important roles in biofilms formation and production of extracellular polysaccharides. Furthermore, the deletion mutants (ΔcheA and ΔcheA-R) were defective in competitive adsorption and colonization on the root surface of host plants...
February 9, 2018: Molecular Plant-microbe Interactions: MPMI
Chelsie E Armbruster, Harry L T Mobley, Melanie M Pearson
Proteus mirabilis , a Gram-negative rod-shaped bacterium most noted for its swarming motility and urease activity, frequently causes catheter-associated urinary tract infections (CAUTIs) that are often polymicrobial. These infections may be accompanied by urolithiasis, the development of bladder or kidney stones due to alkalinization of urine from urease-catalyzed urea hydrolysis. Adherence of the bacterium to epithelial and catheter surfaces is mediated by 17 different fimbriae, most notably MR/P fimbriae...
February 2018: EcoSal Plus
Nathan L Hendel, Matthew Thomson, Wallace F Marshall
An important question in cell biology is whether cells are able to measure size, either whole cell size or organelle size. Perhaps cells have an internal chemical representation of size that can be used to precisely regulate growth, or perhaps size is just an accident that emerges due to constraint of nutrients. The eukaryotic flagellum is an ideal model for studying size sensing and control because its linear geometry makes it essentially one-dimensional, greatly simplifying mathematical modeling. The assembly of flagella is regulated by intraflagellar transport (IFT), in which kinesin motors carry cargo adaptors for flagellar proteins along the flagellum and then deposit them at the tip, lengthening the flagellum...
February 6, 2018: Biophysical Journal
Qiong Wu, Kang Gao, Shuzhi Zheng, Xin Zhu, Yinwen Liang, Junmin Pan
Calcium has been implicated in the motility, assembly, disassembly, and deflagellation of the eukaryotic flagellum or cilium (exchangeable terms). Calmodulin (CaM) is known to be critical for flagellar motility; however, it is unknown whether and how CaM is involved in other flagella-related activities. We have studied CaM in Chlamydomonas, a widely used organism for ciliary studies. CaM is present in the cell body and the flagellum, with enrichment in the basal body region. Loss of CaM causes shortening of the nucleus basal body connector and impairs flagellar motility and assembly but not flagellar disassembly...
January 29, 2018: FASEB Journal: Official Publication of the Federation of American Societies for Experimental Biology
Eugeny Brusentsev, Elena Kizilova, Valentina Mokrousova, Valeria Kozhevnikova, Irina Rozhkova, Sergei Amstislavsky
The study represents a comparison of cryopreservation of domestic cat epididymal spermatozoa with two commercially available freezing media: CaniPlus Freeze (CPF) and SpermFreeze (SF). The viability of nonfrozen spermatozoa evaluated by the VitalScreen test was 68.7 ± 3.0%. These figures were lower for the frozen-thawed spermatozoa: 51.2 ± 6.3% for CPF group and 54.4 ± 3.1% for SF group. The motility of nonfrozen spermatozoa was 57.2 ± 4.5%. These figures were reduced in both frozen-thawed groups; however, there was no significant difference in these parameters between CPF (30...
December 29, 2017: Theriogenology
Margrethe Boyd, Frank Rosenzweig, Matthew D Herron
The advent of multicellularity was a watershed event in the history of life, yet the transition from unicellularity to multicellularity is not well understood. Multicellularity opens up opportunities for innovations in intercellular communication, cooperation, and specialization, which can provide selective advantages under certain ecological conditions. The unicellular alga Chlamydomonas reinhardtii has never had a multicellular ancestor yet it is closely related to the volvocine algae, a clade containing taxa that range from simple unicells to large, specialized multicellular colonies...
2018: PloS One
Bryan Troxell
Bacteria interact with their host through protein secretion systems and surface structures. Pathogenic bacteria encode protein secretion systems that promote the invasion of the host's tissue, the evasion of the host's immune response, the thwarting microbial competitors, and ultimately survival within the host. For motile bacteria, the presence of extracellular flagella provides the host with a structural motif used for activation of the immune system. Within this issue of Virulence, the article "Identification of a novel gene in ROD9 island of Salmonella Enteritidis involved in the alteration of virulence-associated protein expression" describes the contribution of a gene, SEN1005, toward host-pathogen interaction...
January 30, 2018: Virulence
Martin Broberg, James Doonan, Filip Mundt, Sandra Denman, James E McDonald
BACKGROUND: Britain's native oak species are currently under threat from acute oak decline (AOD), a decline-disease where stem bleeds overlying necrotic lesions in the inner bark and larval galleries of the bark-boring beetle, Agrilus biguttatus, represent the primary symptoms. It is known that complex interactions between the plant host and its microbiome, i.e. the holobiont, significantly influence the health status of the plant. In AOD, necrotic lesions are caused by a microbiome shift to a pathobiome consisting predominantly of Brenneria goodwinii, Gibbsiella quercinecans, Rahnella victoriana and potentially other bacteria...
January 30, 2018: Microbiome
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