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41.
Andrew C Doxey Michael DJ Lynch Kirsten M Müller Elizabeth M Meiering Brendan J McConkey 《BMC evolutionary biology》2008,8(1):316
Background
Clostridial neurotoxins (CNTs) are the most deadly toxins known and causal agents of botulism and tetanus neuroparalytic diseases. Despite considerable progress in understanding CNT structure and function, the evolutionary origins of CNTs remain a mystery as they are unique to Clostridium and possess a sequence and structural architecture distinct from other protein families. Uncovering the origins of CNTs would be a significant contribution to our understanding of how pathogens evolve and generate novel toxin families. 相似文献42.
WS Watkins R Thara BJ Mowry Y Zhang DJ Witherspoon W Tolpinrud MJ Bamshad S Tirupati R Padmavati H Smith D Nancarrow C Filippich LB Jorde 《BMC genetics》2008,9(1):1-17
Background
Major population movements, social structure, and caste endogamy have influenced the genetic structure of Indian populations. An understanding of these influences is increasingly important as gene mapping and case-control studies are initiated in South Indian populations.Results
We report new data on 155 individuals from four Tamil caste populations of South India and perform comparative analyses with caste populations from the neighboring state of Andhra Pradesh. Genetic differentiation among Tamil castes is low (RST = 0.96% for 45 autosomal short tandem repeat (STR) markers), reflecting a largely common origin. Nonetheless, caste- and continent-specific patterns are evident. For 32 lineage-defining Y-chromosome SNPs, Tamil castes show higher affinity to Europeans than to eastern Asians, and genetic distance estimates to the Europeans are ordered by caste rank. For 32 lineage-defining mitochondrial SNPs and hypervariable sequence (HVS) 1, Tamil castes have higher affinity to eastern Asians than to Europeans. For 45 autosomal STRs, upper and middle rank castes show higher affinity to Europeans than do lower rank castes from either Tamil Nadu or Andhra Pradesh. Local between-caste variation (Tamil Nadu RST = 0.96%, Andhra Pradesh RST = 0.77%) exceeds the estimate of variation between these geographically separated groups (RST = 0.12%). Low, but statistically significant, correlations between caste rank distance and genetic distance are demonstrated for Tamil castes using Y-chromosome, mtDNA, and autosomal data.Conclusion
Genetic data from Y-chromosome, mtDNA, and autosomal STRs are in accord with historical accounts of northwest to southeast population movements in India. The influence of ancient and historical population movements and caste social structure can be detected and replicated in South Indian caste populations from two different geographic regions. 相似文献43.
Fourteen native strains of Trichoderma spp. from wildand agricultural pathosystems in the state of Yucatan, Mexico, with growth-promoting ability of Capsicum chinense Jacq. seedlings were evaluated and antagonistic effect of their filtrate against second-stage juveniles (J2) of Meloidogyne incognita. The strains Th05-02 and Th27-08 showed the best significant effects on plant hight variable increments 55.57 and 47.62%, theTh07-04 with 29.48% more root length, theTh02-01 and Th07-04 isolates increased from 48.71 to 84.61% in volume radical and 53.40% of total dry biomass. Statistical analysis (p≤0.001) of Th43 and Th43-13-14 filtrates caused 100% mortality at 24 and 48h. In the test of reversibility to 24 h after replacing the filtrates Th43-13, Th43-14, TH09-06 and TH20-07 by sterile distilled water, the J2 did not recover their viability, so they were considered as the best potential strains of Trichoderma spp. with antagonistic capacity in J2 of M.incognita. 相似文献
44.
M Kale R Ramsey-Goldman S Bernatsky MB Urowitz D Gladman PR Fortin M Petri E Yelin S Manzi S Edworthy O Nived S-C Bae D Isenberg A Rahman JG Hanly C Gordon S Jacobsen E Ginzler DJ Wallace GS Alarcón MA Dooley L Gottesman K Steinsson A Zoma J-L Senécal S Barr G Sturfelt L Dreyer L Criswell J Sibley JL Lee AE Clarke 《Arthritis research & therapy》2012,14(Z3):A15
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Pairwise likelihood methods for inference in image models 总被引:3,自引:0,他引:3
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Recent horizontal transfer of a mariner transposable element among and between Diptera and Neuroptera 总被引:11,自引:4,他引:7
Transposable elements of the mariner family are widespread among insects
and other invertebrates, and initial analyses of their relationships
indicated frequent occurrence of horizontal transfers between hosts. A
specific PCR assay was used to screen for additional members of the
irritans subfamily of mariners in more than 400 arthropod species.
Phylogenetic analysis of cloned PCR fragments indicated that relatively
recent horizontal transfers had occurred into the lineages of a fruit fly
Drosophila ananassae, the horn fly Haematobia irritans, the African malaria
vector mosquito Anopheles gambiae, and a green lacewing Chrysoperla
plorabunda. Genomic dot-blot analysis revealed that the copy number in
these species varies widely, from about 17,000 copies in the horn fly to
three copies in D. ananassae. Multiple copies were sequenced from genomic
clones from each of these species and four others with related elements.
These sequences confirmed the PCR results, revealing extremely similar
elements in each of these four species (greater than 88% DNA and 95% amino
acid identity). In particular, the consensus sequence of the transposase
gene of the horn fly elements differs by just two base pairs out of 1,044
from that of the lacewing elements. The mosquito lineage has diverged from
the other Diptera for over 200 Myr, and the neuropteran last shared a
common ancestor with them more than 265 Myr ago, so this high similarity
implies that these transposons recently transferred horizontally into each
lineage. Their presence in only the closest relatives in at least the
lacewing lineage supports this hypothesis. Such horizontal transfers
provide an explanation for the evolutionary persistence and widespread
distribution of mariner transposons. We propose that the ability to
transfer horizontally to new hosts before extinction by mutation in the
current host constitutes the primary selective constraint maintaining the
sequence conservation of mariners and perhaps other DNA-mediated elements.
相似文献
50.
The effects of selective ibotenate lesions of the complete hippocampus (CHip), the hippocampal ventral pole (VP), or the medial prefrontal cortex (mPFC) in male rats were assessed on several measures related to energy regulation (i.e., body weight gain, food intake, body adiposity, metabolic activity, general behavioral activity, conditioned appetitive responding). The testing conditions were designed to minimize the nonspecific debilitating effects of these surgeries on intake and body weight. Rats with CHip and VP lesions exhibited significantly greater weight gain and food intake compared with controls. Furthermore, CHip-lesioned rats, but not rats with VP lesions, showed elevated metabolic activity, general activity in the dark phase of the light-dark cycle, and greater conditioned appetitive behavior, compared with control rats without these brain lesions. In contrast, rats with mPFC lesions were not different from controls on any of these measures. These results indicate that hippocampal damage interferes with energy and body weight regulation, perhaps by disrupting higher-order learning and memory processes that contribute to the control of appetitive and consummatory behavior. 相似文献