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Flagellar morphology

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
Fernando Gómez
The marine dinoflagellate Erythropsidinium possesses an ocelloid, the most elaborate photoreceptor organelle known in a unicellular organism, and a piston, a fast contractile appendage unknown in any other organism. The ocelloid is able to rotate, often before the cell swims. The ocelloid contains lenses that function to concentrate light. The flagellar propulsion is atrophied, and the piston is responsible for locomotion through successive extensions and contractions. During the 'locomotion mode', the contraction is ~4 times faster than the extension...
February 16, 2017: Journal of Phycology
Alexander O Frolov, Marina N Malysheva, Anna I Ganyukova, Vyacheslav Yurchenko, Alexei Y Kostygov
Blastocrithidia papi sp. n. is a cyst-forming trypanosomatid parasitizing firebugs (Pyrrhocoris apterus). It is a member of the Blastocrithidia clade and a very close relative of B. largi, to which it is almost identical through its SSU rRNA gene sequence. However, considering the SL RNA gene these two species represent quite distinct, not even related typing units. Morphological analysis of the new species revealed peculiar or even unique features, which may be useful for future taxonomic revision of the genus Blastocrithidia...
November 16, 2016: European Journal of Protistology
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
Naoji Yubuki, Sam S C Huang, Brian S Leander
The Fornicata (Excavata) is a group of microbial eukaryotes consisting of both free-living lineages (e.g., Carpediemonas) and parasitic lineages (e.g. Giardia and Retortamonas) that share several molecular and ultrastructural traits. Carpediemonas-like organisms (CLOs) are free-living lineages that diverged early within the Fornicata, making them important for inferring the early evolutionary history of the group. Molecular phylogenetic analyses of free-living fornicates, including sequences from environmental PCR surveys, have demonstrated that CLOs form six different lineages...
December 2016: Protist
Norihiro Takekawa, Seiji Kojima, Michio Homma
The bacterial flagellar motor is a rotary motor complex composed of various proteins. The motor contains a central rod, multiple ring-like structures and stators. The Na(+)-driven polar flagellar motor of the marine bacterium Vibrio alginolyticus has a specific ring, called the 'T-ring', which consists of two periplasmic proteins, MotX and MotY. The T-ring is essential for assembly of the torque-generating unit, the PomA/PomB stator complex, into the motor. To investigate the role of the T-ring for motor function, we performed random mutagenesis of the motX gene on a plasmid...
October 25, 2016: Journal of Biochemistry
Amir Amiri-Yekta, Charles Coutton, Zine-Eddine Kherraf, Thomas Karaouzène, Pauline Le Tanno, Mohammad Hossein Sanati, Marjan Sabbaghian, Navid Almadani, Mohammad Ali Sadighi Gilani, Seyedeh Hanieh Hosseini, Salahadin Bahrami, Abbas Daneshipour, Maurizio Bini, Christophe Arnoult, Roberto Colombo, Hamid Gourabi, Pierre F Ray
STUDY QUESTION: Can whole-exome sequencing (WES) of patients with multiple morphological abnormalities of the sperm flagella (MMAF) identify causal mutations in new genes or mutations in the previously identified dynein axonemal heavy chain 1 (DNAH1) gene? SUMMARY ANSWER: WES for six families with men affected by MMAF syndrome allowed the identification of DNAH1 mutations in four affected men distributed in two out of the six families but no new candidate genes were identified...
October 26, 2016: Human Reproduction
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
Aamir Maqbool, Imtiaz Ahmed
The present study deals with the description of a new piscine trypanosome species found infecting the fresh water fish Schizothorax plagiostomus Heckel from river Jhelum, Srinagar, J&K, India and evaluating the haematological parameters of the infected fish. Haematological examination of S. plagiostomus revealed 61.1 % infection with an intensity of 1-9 trypanosomes/100 RBC's. Small (26.9 ± 1.39 µm) and large (47.17 ± 3.50 µm) forms of the trypanosome were observed in light microscopy investigations, revealing the dimorphic nature of the species...
September 2016: Journal of Parasitic Diseases: Official Organ of the Indian Society for Parasitology
Jun-Hao Zhou, Qi-Zhao Zhou, Jian-Kun Yang, Xiao-Ming Lyu, Jun Bian, Wen-Bin Guo, Zi-Jian Chen, Ming Xia, Hui Xia, Tao Qi, Xin Li, Cun-Dong Liu
Cysteine-rich secretory protein 2 (CRISP2) is an important protein in spermatozoa that plays roles in modulating sperm flagellar motility, the acrosome reaction, and gamete fusion. Spermatozoa lacking CRISP2 exhibit low sperm motility and abnormal morphology. However, the molecular mechanisms underlying the reduction of CRISP2 in asthenoteratozoospermia (ATZ) remain unknown. In this study, low expression of CRISP2 protein rather than its mRNA was observed in the ejaculated spermatozoa from ATZ patients as compared with normozoospermic males...
August 12, 2016: Asian Journal of Andrology
Leandro S Sangenito, Diego S Gonçalves, Sergio H Seabra, Claudia M d'Avila-Levy, André L S Santos, Marta H Branquinha
There is a general lack of effective and non-toxic chemotherapeutic agents against Chagas' disease despite more than a century of research. In this regard, we have verified the impact of human immunodeficiency virus aspartic peptidase inhibitors (HIV-PIs) on the viability and morphology of infective trypomastigote forms of Trypanosoma cruzi as well as on the aspartic peptidase and proteasome activities produced by this parasite. The effects of HIV-PIs on viability were assessed by counting motile parasites in a Neubauer chamber...
October 2016: International Journal of Antimicrobial Agents
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
Brijesh Kumar, Silvia T Cardona
Burkholderia cenocepacia belongs to the Burkholderia cepacia complex (Bcc), a group of at least 18 distinct species that establish chronic infections in the lung of people with the genetic disease cystic fibrosis (CF). The sputum of CF patients is rich in amino acids and was previously shown to increase flagellar gene expression in B. cenocepacia. We examined flagellin expression and flagellar morphology of B. cenocepacia grown in synthetic cystic fibrosis sputum medium (SCFM) compared to minimal medium. We found that CF nutritional conditions induce increased motility and flagellin expression...
2016: Frontiers in Cellular and Infection Microbiology
Takashi Shiratori, Ken-Ichiro Ishida
We report a new heterotrophic cryptomonad Hemiarma marina n. g., n. sp. that was collected from a seaweed sample from the Republic of Palau. In our molecular phylogenetic analyses using the small subunit ribosomal RNA gene, H. marina formed a clade with two marine environmental sequences, and the clade was placed as a sister lineage of the freshwater cryptomonad environmental clade CRY1. Alternatively, in the concatenated large and small subunit ribosomal RNA gene phylogeny, H. marina was placed as a sister lineage of Goniomonas...
May 24, 2016: Journal of Eukaryotic Microbiology
Pablo Sartori, Veikko F Geyer, Andre Scholich, Frank Jülicher, Jonathon Howard
Cilia and flagella are model systems for studying how mechanical forces control morphology. The periodic bending motion of cilia and flagella is thought to arise from mechanical feedback: dynein motors generate sliding forces that bend the flagellum, and bending leads to deformations and stresses, which feed back and regulate the motors. Three alternative feedback mechanisms have been proposed: regulation by the sliding forces, regulation by the curvature of the flagellum, and regulation by the normal forces that deform the cross-section of the flagellum...
2016: ELife
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
Clémentine Wambergue, Raoudha Zouari, Selima Fourati Ben Mustapha, Guillaume Martinez, Françoise Devillard, Sylviane Hennebicq, Véronique Satre, Sophie Brouillet, Lazhar Halouani, Ouafi Marrakchi, Mounir Makni, Habib Latrous, Mahmoud Kharouf, Florence Amblard, Christophe Arnoult, Pierre F Ray, Charles Coutton
STUDY QUESTION: Does DNAH1 status influence intracytoplasmic sperm injection (ICSI) outcomes for patients with multiple morphological abnormalities of the sperm flagella (MMAF)? SUMMARY ANSWER: Despite a highly abnormal morphology, sperm from MMAF patients with DNAH1 mutations have a low aneuploidy rate and good nuclear quality, leading to good embryonic development following ICSI and a high pregnancy rate. WHAT IS KNOWN ALREADY: Teratozoospermia represents a heterogeneous group including a wide range of phenotypes...
June 2016: Human Reproduction
Emmanuel Tetaud, Michèle Lefebvre, Diane-Ethna M'Bang-Benet, Lucien Crobu, Corinne Blancard, Yvon Sterkers, Michel Pages, Patrick Bastien, Gilles Merlin
TbFlabarin is the Trypanosoma brucei orthologue of the Leishmania flagellar protein LdFlabarin but its sequence is 33% shorter than LdFlabarin, as it lacks a C-terminal domain that is indispensable for LdFlabarin to localize to the Leishmania flagellum. TbFlabarin is mainly expressed in the procyclic forms of the parasite and localized to the flagellum, but only when two palmitoylable cysteines at positions 3 and 4 are present. TbFlabarin is more strongly attached to the membrane fraction than its Leishmania counterpart, as it resists complete solubilization with as much as 0...
July 2016: Experimental Parasitology
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
Helen Pinto Santos, Marcelo Silva Barcellos, Aline Beatriz Reis, Heidi Dolder, José Lino-Neto
Sperm morphology of the parasitoid Muscidifurax uniraptor was investigated under light and transmission electron microscopy. M. uniraptor sperm are filiform, spiraled, approximately 150 μm in length, with a distinctive head, hooded by an extracellular sheath and a flagellum. This extracellular layer, from which many filaments radiate, measures approximately 90 nm in thickness and covers a small acrosome and the anterior nuclear region. The acrosome is composed of an acrosomal vesicle and a perforatorium with its base inserted in the nuclear tip...
May 2016: Arthropod Structure & Development
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