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71.
A homologous family of UDP- N -acetylgalactosamine: polypeptide N -
acetylgalactosaminyltransferases (GalNAc-transferases) initiate O-
glycosylation. These transferases share overall amino acid sequence
similarities of approximately 45-50%, but segments with higher similarities
of approximately 80% are found in the putative catalytic domain. Here we
have characterized the genomic organization of the coding regions of three
GalNAc-transferase genes and determined their chromosomal localization. The
coding regions of GALNT1 , -T2 , and -T3 were found to span 11, 16, and 10
exons, respectively. Several intron/exon boundaries were conserved within
the three genes. One conserved boundary was shared in a homologous C.
elegans GalNAc- transferase gene. Fluorescence in situ hybridization showed
that GALNT1 , -T2 , and -T3 are localized at chromosomes 18q12-q21,
1q41-q42, and 2q24-q31, respectively. These results suggest that the
members of the polypeptide GalNAc-transferase family diverged early in
evolution from a common ancestral gene through gene duplication.
相似文献
72.
73.
Dykstra B Kent D Bowie M McCaffrey L Hamilton M Lyons K Lee SJ Brinkman R Eaves C 《Cell Stem Cell》2007,1(2):218-229
Heterogeneity in the differentiation behavior of hematopoietic stem cells is well documented but poorly understood. To investigate this question at a clonal level, we isolated a subpopulation of adult mouse bone marrow that is highly enriched for multilineage in vivo repopulating cells and transplanted these as single cells, or their short-term clonal progeny generated in vitro, into 352 recipients. Of the mice, 93 showed a donor-derived contribution to the circulating white blood cells for at least 4 months in one of four distinct patterns. Serial transplantation experiments indicated that two of the patterns were associated with extensive self-renewal of the original cell transplanted. However, within 4 days in vitro, the repopulation patterns subsequently obtained in vivo shifted in a clone-specific fashion to those with less myeloid contribution. Thus, primitive hematopoietic cells can maintain distinct repopulation properties upon serial transplantation in vivo, although these properties can also alter rapidly in vitro. 相似文献
74.
Pukala TL Doyle JR Llewellyn LE Kuhn-Nentwig L Apponyi MA Separovic F Bowie JH 《The FEBS journal》2007,274(7):1778-1784
Cupiennin 1a (GFGALFKFLAKKVAKTVAKQAAKQGAKYVVNKQME-NH2) is a potent venom component of the spider Cupiennius salei. Cupiennin 1a shows multifaceted activity. In addition to known antimicrobial and cytolytic properties, cupiennin 1a inhibits the formation of nitric oxide by neuronal nitric oxide synthase at an IC50 concentration of 1.3 +/- 0.3 microM. This is the first report of neuronal nitric oxide synthase inhibition by a component of a spider venom. The mechanism by which cupiennin 1a inhibits neuronal nitric oxide synthase involves complexation with the regulatory protein calcium calmodulin. This is demonstrated by chemical shift changes that occur in the heteronuclear single quantum coherence spectrum of 15N-labelled calcium calmodulin upon addition of cupiennin 1a. The NMR data indicate strong binding within a complex of 1 : 1 stoichiometry. 相似文献
75.
76.
The forest batis, Batis mixta, is a common bird of the forests of the Eastern Arc Mountains of Tanzania and in some adjacent montane and coastal forests. Through new collecting efforts in most of this range we documented a well-marked change in morphology in the middle of the range. Supplementary genetic studies of the historical population structure suggest connectivity among the south-western and northern/coastal populations, but not between these parapatric groups. It is concluded that two species are involved, and a new name B. crypta is proposed for the south-western populations. A marked genetic break also exists towards B. capensis sola in northern Malawi. The morphologically distinctive form reichenowi in south-eastern Tanzania is genetically nested within B. mixta, and for now we keep it as a subspecies of B. mixta. 相似文献
77.
Timothy M. Crowe Rauri C. K. Bowie Paulette Bloomer Tshifhiwa G. Mandiwana Terry A. J. Hedderson Ettore Randi Sergio L. Pereira Julia Wakeling 《Cladistics : the international journal of the Willi Hennig Society》2006,22(6):495-532
The phylogenetic relationships, biogeography and classification of, and morpho‐behavioral (M/B) evolution in, gamebirds (Aves: Galliformes) are investigated. In‐group taxa (rooted on representatives of the Anseriformes) include 158 species representing all suprageneric galliform taxa and 65 genera. The characters include 102 M/B attributes and 4452 nucleic acid base pairs from mitochondrial cytochrome b (CYT B), NADH dehydrogenase subunit 2 (ND2), 12S ribosomal DNA (12S) and control region (CR), and nuclear ovomucoid intron G (OVO‐G). Analysis of the combined character data set yielded a single, completely resolved cladogram that had the highest levels of jackknife support, which suggests a need for a revised classification for the phasianine galliforms. Adding 102 M/B characters to the combined CYT B and ND2 partitions (2184 characters) decisively overturns the topology suggested by analysis of the two mtDNA partitions alone, refuting the view that M/B characters should be excluded from phylogenetic analyses because of their relatively small number and putative character state ambiguity. Exclusion of the OVO‐G partition (with > 70% missing data) from the combined data set had no effect on cladistic structure, but slightly lowered jackknife support at several nodes. Exclusion of third positions of codons in an analysis of a CYT B + ND2 partition resulted in a massive loss of resolution and support, and even failed to recover the monophyly of the Galliformes with jackknife support. A combined analysis of putatively less informative, “non‐coding” characters (CYT B/ND2 third position sites + CR +12S + OVO‐G sequences) yielded a highly resolved consensus cladogram congruent with the combined‐evidence cladogram. Traditionally recognized suprageneric galliform taxa emerging in the combined cladogram are: the families Megapodiidae (megapodes), Cracidae (cracids), Numididae (guineafowls), Odontophoridae (New World quails) and Phasianidae (pheasants, pavonines, partridges, quails, francolins, spurfowls and grouse) and the subfamilies Cracinae (curassows, chachalacas and the horned guan), Penelopinae (remaining guans), Pavoninae sensu lato (peafowls, peacock pheasants and argus pheasants), Tetraoninae (grouse) and Phasianinae (pheasants minus Gallus). The monophyly of some traditional groupings (e.g., the perdicinae: partridges/quails/francolins) is rejected decisively, contrasted by the emergence of other unexpected groupings. The most remarkable phylogenetic results are the placement of endemic African galliforms as sisters to geographically far‐distant taxa in Asia and the Americas. Biogeographically, the combined‐data cladogram supports the hypothesis that basal lineages of galliforms diverged prior to the Cretaceous/Tertiary (K‐T) Event and that the subsequent cladogenesis was influenced by the break‐up of Gondwana. The evolution of gamebirds in Africa, Asia and the Americas has a far more complicated historical biogeography than suggested to date. With regard to character evolution: spurs appear to have evolved at least twice within the Galliformes; a relatively large number of tail feathers (≥ 14) at least three times; polygyny at least twice; and sexual dimorphism many times. © The Willi Hennig Society 2006. 相似文献
78.
Billy Nguembock Alice Cibois Rauri C. K. Bowie Corinne Cruaud Eric Pasquet 《Journal of avian biology》2009,40(2):113-125
African jungle babblers or illadopsises, genus Illadopsis Heine, 1859, are small shy babblers which occupy the undergrowth of African humid forest habitats. The taxonomy of Illadopsis as well as its biogeography are currently poorly known because the morphological differentiation is rather subtle and no phylogenetic analysis has been undertaken. To investigate these issues, we sequenced four loci (mitochondrial ND2 and ND3, and nuclear myoglobin intron 2 and β-fibrinogen intron 5) for the seven species of Illadopsis . Our analyses retrieve the monophyly of Illadopsis and suggest that I. albipectus and I. cleaveri , I. puveli and I. rufescens , some individuals of I. rufipennis and I. pyrrhoptera are sister taxa respectively. I. fulvescens appears to be an isolated taxon and our data reveal several cases of "incipient speciation" among its populations. Our dating analyses, using a Bayesian relaxed-clock method, reveal that most splits in Illadopsis occurred synchronously around the Plio-Pleistocene transition, suggesting that some diversification events in African forest taxa took place before the onset of the large-amplitude climatic cycles of the Pleistocene epoch. Thus, the diversification of African taxa in time and space to be more complex than the Pleistocene time frame traditionally associated with the diversification of African forest taxa. Instead we observe a process of differentiation which roughly corresponds to the broadly hypothesised lowland refugia of upper Guinea, eastern and western Guinea-Congolia, although the time frame of this divergence well predates the Pleistocene epoch. Our results also suggest that deep genetic divergences do exist among species complexes of African birds which differ only slightly in morphological characters. As such, molecular analyses are powerful and essential tools if we are to construct the evolutionary history of such lineages in a meaningful manner. 相似文献
79.
Marta de Ponte Machado Kevin A. Feldheim Anna B. Sellas Rauri C. K. Bowie 《Conservation Genetics》2009,10(4):1033-1036
We describe the isolation of 10 microsatellite loci from the Great White Pelican using an enrichment protocol. All loci were
variable with the number of alleles ranging from 2 to 19, and observed heterozygosity ranging from 0.261 to 0.913. Two loci
were out of Hardy–Weinberg equilibrium, although in each case this was restricted to one of the two populations screened.
None of the loci were linked. Eight to 10 loci PCR-amplified in three related species: Brown, American White and Pink-backed
Pelicans. These loci should prove to be widely applicable to studies of phylogeography and demography in pelicans globally. 相似文献
80.
Pilar del Hoyo Alberto García-Redondo Fernando de Bustos José Antonio Molina Youssef Sayed Hortensia Alonso-Navarro Luis Caballero Joaquín Arenas José AG Agúndez Félix Javier Jiménez-Jiménez 《BMC neurology》2010,10(1):95