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Tubulin Gene (tubulin + gene)
Selected Abstracts,-TUBULIN GENE OF PORPHYRA PURPUREA ( RHODOPHYTA),JOURNAL OF PHYCOLOGY, Issue 5 2002Ron M. MacKay The life cycle of the marine red alga Porphyra purpurea (Roth) C. Agardh includes a shell-boring filamentous sporophyte and a leafy gametophyte. A single intronless gene for the microtubule protein ,-tubulin was discovered by molecular cloning of P. purpurea cDNA and genomic DNA. This gene, named TubB1, encodes a ,-tubulin with a divergent amino acid sequence, showing 74% identity with the conserved ,-tubulin of Chlamydomonas reinhardtii P. A. Dangeard. Southern hybridization analysis of nuclear DNA confirmed that P. purpurea has a single TubB1 gene. Transcripts (1.8 kb) of TubB1 are present in the sporophyte and gametophyte. Codon bias indicates strong expression of TubB1. The divergent nature of the TubB1 genes suggests that the absence of axonemal structures has allowed substantial genetic drift in red algal ,-tubulin genes. [source] Phylogeographic variation among isolates of the Sirococcus conigenus P groupFOREST PATHOLOGY, Issue 1 2007H. Konrad Summary In this study the phylogeographic variation among isolates of the Sirococcus conigenus P group and the phylogenetic relationships of S. conigenus with Sirococcus clavigignenti-juglandacearum and other species previously placed in the genus Sirococcus were investigated. A collection of 33 isolates originating from Picea, Pinus and Larix in Europe, North America and Bhutan were characterized by sequence analyses of the internal transcribed spacer (ITS) region (including ITS1, 5.8S ribosomal DNA, ITS2) of the nuclear rDNA and a portion of the , -tubulin gene. In phylogenetic analyses most isolates from pine, spruce and larch formed a distinct clade, representing the P group of S. conigenus, which was separated from the T group of this pathogen. Four isolates from Picea in Europe and Canada formed a third clade within S. conigenus and these isolates are referred to as the S group. The P group consisted of five distinct ITS haplotypes, which partly differed in their optimum growth temperature and their growth rates at 25°C on malt extract agar. Nested clade analysis resolved the five haplotypes into three distinct clades and revealed significant genetic/geographic associations for some of the haplotypes. Parsimony analysis of the small subunit (18S) ribosomal DNA sequences confirmed the phylogenetic affinities between S. conigenus and S. clavigignenti-juglandacearum. In contrast, Godronia cassandrae and Hormococcus conorum, which formerly had been placed in the genus Sirococcus, were found to be only distantly related to S. conigenus and S. clavigignenti-juglandacearum. [source] Nature of Resistance to Methyl Benzimidazole Carbamate Fungicides in Fusarium oxysporum f.sp. lilii and F. oxysporum f.sp. gladioli in TaiwanJOURNAL OF PHYTOPATHOLOGY, Issue 11-12 2009Wen Hsin Chung Abstract Fusarium oxysporum f.sp. gladioli and F. oxysporum f.sp. lilii cause corm rot and yellowing of gladiolus and lilies respectively. Resistance among isolates of these two pathogens to two benzimidazole (methyl benzimidazole carbamate: MBC) fungicides, benomyl and thiabendazole, has been identified. However, sensitivity to other benzimidazole fungicides among isolates of F. oxysporum f.sp. gladioli and F. oxysporum f.sp. lilii remains unclear. Sensitivity among isolates of these two pathogens to benomyl, thiophanate-methyl, carbendazim and thiabendazole were evaluated in this study. Results showed that among six F. oxysporum f.sp. gladioli isolates, one was highly resistant, four were moderately resistant and one was highly sensitive to benomyl, five were highly resistant to thiophanate-methyl, four were sensitive and one was highly sensitive to carbendazim and all six isolates were sensitive to thiabendazole. Among the 13 F. oxysporum f.sp. lilii isolates tested, three were moderately resistant and 10 were highly sensitive to benomyl, and five were highly resistant, three were moderately resistant and five were sensitive to thiophanate-methyl. While all isolates were highly sensitive or sensitive to carbendazim and thiabendazole. These results strongly suggest that the mode of fungicide resistance in these two pathogens varies among members of the benzimidazole fungicide group and that cross resistance does not always occur. Sequence analysis of the partially amplified , -tubulin gene indicated that mutation in codons 198 and 200 had not occurred in the benzimidazole resistant isolates. It was concluded that resistance found in Taiwan isolates of F. oxysporum f.sp. gladioli and F. oxysporum f.sp. lilii to these fungicides may be due to some other mechanism. [source] Characterization of ,-tubulin gene distinctively presented in a cytoplasmic male sterile and its maintainer line of non-heading Chinese cabbageJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 2 2009Jingyi Zhang Abstract BACKGROUND: Microtubules are prominent components of the cytoskeleton in every eukaryotic cell. Plant microtubules are essential for a wide variety of cellular functions, including generation of cell polarity, intracellular transport, positioning of organelles, cell wall deposition and cell division. The major component of microtubules is tubulin, an ,,, heterodimer protein with a molecular mass of each subunit of around 50 kDa. Tubulin exists in cells as a mixture of polypeptides differing in their isoelectric points. Some post-translational modifications of tubulins are thought to modulate the functions and localization of microtubules within the cell. RESULTS: The complete sequence of a single-copy ,-tubulin gene Tuba1, belonging to a multiple gene family of non-heading Chinese cabbage (Brassica campestris ssp. chinensis Makino), was obtained. The gene was expressed in high levels in young leaves and stamens, and it was also highly expressed during all stages of microsporogenesis in the maintainer. However, there was a distinct difference in ,-tubulin expression between the sterile stage and the normal stages of pollen in a cytoplasmic male sterility line and its maintainer. CONCLUSION:Tuba1 was significantly related to the cell division and elongation of non-heading Chinese cabbage, demonstrating that this gene played an important role in the development of pollen and may be closely related to male sterility. Copyright © 2008 Society of Chemical Industry [source] Molecular phylogeny of the freshwater sponges in Lake BaikalJOURNAL OF ZOOLOGICAL SYSTEMATICS AND EVOLUTIONARY RESEARCH, Issue 2 2003H. C. Schröder Abstract The phylogenetic relationship of the freshwater sponges (Porifera) in Lake Baikal is not well understood. A polyphyletic and/or monophyletic origin have been proposed. The (endemic) Baikalian sponges have been subdivided into two families: endemic Lubomirskiidae and cosmopolitan Spongillidae. In the present study, two new approaches have been made to resolve the phylogenetic relationship of Baikalian sponges; analysis of (1) nucleotide sequences from one mitochondrial gene, the cytochrome oxidase subunit I (COI) and of (2) one selected intron from the tubulin gene. Specimens from the following endemic Baikalian sponge species have been studied; Lubomirskia baicalensis , Baikalospongia intermedia, Baikalospongia recta , Baikalospongia bacillifera and Swartschewskia papyracea . They are all grouped to the family of Lubomirskiidae. Sequence comparisons were performed with the ubiquitously distributed freshwater sponge Spongilla lacustris (family Spongillidae) as well as with one marine sponge, Suberites domuncula . A sequence comparison, of the mitochondrial COI gene revealed a monophyletic grouping of the endemic Baikalian sponges with S. lacustris as the most related species to the common ancestor. The sequences of the COI gene from B. recta , B. intermedia , B. bacillifera and L. baicalensis were found to be identical and separated from those of S. lacustris and S. papyracea . In a second approach, the exon/intron sequences framing the intron-2 of the sponge tubulin gene were chosen for the phylogenetic analysis. The intron sequences were aligned and used for construction of a phylogenetic tree. This analysis revealed again a monophyletic grouping with S. lacustris as the closest related species to the common ancestor. It is concluded that the Baikalian sponges, which have been studied here, are of monophyletic origin. Furthermore, the data suggest that the endemic species S. papyracea is the phylogenetically oldest, extant, endemic Baikalian sponge species. Zusammenfassung Die phylogenetischen Beziehungen der Süßwasserschwämme [Porifera] des Baikalsees sind nur wenig verstanden; sowohl ein polyphyletischer als auch monophyletischer Urspung werden vermutet. Die Baikalschwämme werden in zwei Familien, Lubomirskiidae und Spongillidae, eingeteilt. In der vorliegenden Arbeit wird versucht, die phylogenetischen Beziehungen der Baikalschwämme über zwei Wege aufzuklären: über (i) eine Analyse der Nukleotidsequenzen eines Teils des mitochondrialen Gens der Cytochromoxidase-Untereinheit I (COI) und (ii) eines ausgewählten Introns des Tubulingens. Folgende endemischen Spezies wurden untersucht: Lubomirskia baicalensis , Baikalospongia intermedia , Baikalospongia recta , Baikalospongia bacillifera und Swartschewskia papyracea . Sie werden alle der Familie der Lubomirskiidae zugerechnet. Die Sequenzen wurden mit den entsprechenden Sequenzen des ubiquitär vorkommenden Süßwasserschwammes Spongilla lacustris sowie des Meeresschwammes Suberites domuncula verglichen. Die Sequenzvergleiche der mitochondrialen COI-Gene zeigten, daß die Baikalschwämme monophyletischen Ursprungs sind und zusammen mit S. lacustris von einem gemeinsamen Vorfahren abstammen. Die Sequenzen des COI-Gens von B. recta , B. intermedia , B. bacillifera und L. baicalensis sind identisch und trennen sich phylogenetisch von S. lacustris und S. papyracea ab. Bei dem zweiten von uns gewählten Weg wurden die Sequenzen des zweiten Introns des Schwamm-Tubulingens zur phylogenetischen Analyse herangezogen. Auch dabei konnte gezeigt werden, daß die Baikalschwämme , zusammen mit S. lacustris als dem nächsten verwandten gemeinsamen Vorfahren , einen monophyletischen Ursprung haben. S. papyracea stellt den phylogenetisch ältesten endemischen Baikalschwamm dar. [source] Contrasting genetic structures of two parasitic nematodes, determined on the basis of neutral microsatellite markers and selected anthelmintic resistance markersMOLECULAR ECOLOGY, Issue 24 2009A. SILVESTRE Abstract For the first time, the neutral genetic relatedness of natural populations of Trichostrongylid nematodes was investigated in relation to polymorphism of the ,-tubulin gene, which is selected for anthelminthic treatments. The aim of the study was to assess the contribution of several evolutionary processes: migration and genetic drift by neutral genetic markers and selection by anthelminthic treatments on the presence of resistance alleles at ,-tubulin. We studied two nematode species (Teladorsagia circumcincta and Haemonchus contortus) common in temperate climatic zones; these species are characterized by contrasting life history traits. We studied 10 isolated populations of goat nematode parasites: no infected adult goat had been exchanged after the herds were established. Beta-tubulin polymorphism was similar in these two species. One and two ,-tubulin alleles from T. circumcincta and H. contortus respectively were shared by several populations. Most of the ,-tubulin alleles were ,private' alleles. No recombination between alleles was detected in BZ-resistant alleles from T. circumcincta and H. contortus. The T. circumcincta populations have not diverged much since their isolation (FST <0.08), whereas H. contortus displayed marked local genetic differentiation (FST ranging from 0.08 to 0.18). These findings suggest that there are severe bottlenecks in the H. contortus populations, possibly because of their reduced abundance during unfavourable periods and their high reproductive rate, which allows the species to persist even after severe population reduction. Overall, the data reported contradict the hypothesis of the origin of ,-tubulin resistance alleles in these populations from a single mutational event, but two other hypotheses (recurrent mutation generating new alleles in isolated populations and the introduction of existing alleles) emerge as equally likely. [source] Transfer of the ,-tubulin gene of Botrytis cinerea with resistance to carbendazim into Fusarium graminearumPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 5 2010Sheng-Ming Liu Abstract BACKGROUND: Resistance to carbendazim and other benzimidazole fungicides in Botrytis cinerea (Pers. ex Fr.) and most other fungi is usually conferred by mutation(s) in a single chromosomal ,-tubulin gene, often with several allelic mutations. In Fusarium graminearum Schwade, however, carbendazim resistance is not associated with a mutation in the corresponding ,-tubulin gene. RESULTS: The ,-tubulin gene conferring carbendazim resistance in B. cinerea was cloned and connected with two homologous arms of the ,-tubulin gene of F. graminearum by using a double-joint polymerase chain reaction (PCR). This fragment was transferred into F. graminearum via homologous double crossover at the site where the ,-tubulin gene of F. graminearum is normally located (the ,-tubulin gene of F. graminearum had been deleted). The transformants were confirmed and tested for their sensitivity to carbendazim. CONCLUSION: The ,-tubulin gene conferring carbendazim resistance in B. cinerea could not express this resistance in F. graminearum, as transformants were still very sensitive to carbendazim. Copyright © 2010 Society of Chemical Industry [source] ,-TUBULIN GENE OF PORPHYRA PURPUREA ( RHODOPHYTA),JOURNAL OF PHYCOLOGY, Issue 5 2002Ron M. MacKay The life cycle of the marine red alga Porphyra purpurea (Roth) C. Agardh includes a shell-boring filamentous sporophyte and a leafy gametophyte. A single intronless gene for the microtubule protein ,-tubulin was discovered by molecular cloning of P. purpurea cDNA and genomic DNA. This gene, named TubB1, encodes a ,-tubulin with a divergent amino acid sequence, showing 74% identity with the conserved ,-tubulin of Chlamydomonas reinhardtii P. A. Dangeard. Southern hybridization analysis of nuclear DNA confirmed that P. purpurea has a single TubB1 gene. Transcripts (1.8 kb) of TubB1 are present in the sporophyte and gametophyte. Codon bias indicates strong expression of TubB1. The divergent nature of the TubB1 genes suggests that the absence of axonemal structures has allowed substantial genetic drift in red algal ,-tubulin genes. [source] Molecular Mechanisms of Microtubular Organelle Assembly in TetrahymenaTHE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 3 2000JACEK GAERTIG ABSTRACT. Thanks to recent technological advances, the ciliate Tetrahymena thermophila has emerged as an attractive model organism for studies on the assembly of microtubular organelles in a single cell. Tetrahymena assembles 17 types of distinct microtubules, which are localix.ed in cilia, cell cortex, nuclei, and the endoplasm. These diverse microtubules have distinct morphologies, stabilities, and associations with specific Microtubule-Assoeiated Proteins. For example, kinesin-111, a microtubular motor protein, is required for assembly of cilia and is preferentially targeted to microtubules of actively assembled, immature cilia. It is unlikely that the unique properties of individual microtubules are derived from the utilization of diverse tubulin genes, because Tetrahymena expresses only a single isotype of ,-and two isotypes of ,-tubulin. However, Tetrahymena tubulins are modified secondarily by a host of post-translational mechanisms. Each microtubule organelle type displays a unique set of secondary tubulin modifications. The results of systematic in vivo mutational analyses of modification sites indicate a divergence in significance among post-translational mechanisms affecting either ,-or ,-tubulin. Both acetylation and polyglycylation of ,-tubulin are not essential and their complete elimination does not change the cell's phenotype in an appreciable way. However, the multiple polyglycylation sites on ,-tubulin are essential for survival, and their partial elimination dramatically affects cell motility, growth and morphology. Thus, both high-precision targeting of molecular motors to individual organelles as well as organelle-specific tubulin modifications contribute to the creation of diverse microtubules in a single cytoplasm of Tetrahymena. [source] | |||||||||||||