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排序方式: 共有152条查询结果,搜索用时 250 毫秒
1.
Jeff A Johnson Heather RL Lerner Pamela C Rasmussen David P Mindell 《BMC evolutionary biology》2006,6(1):65-12
Background
Populations of the Oriental White-backed Vulture (Gyps bengalensis) have declined by over 95% within the past decade. This decline is largely due to incidental consumption of the non-steroidal anti-inflammatory veterinary pharmaceutical diclofenac, commonly used to treat domestic livestock. The conservation status of other Gyps vultures in southern Asia is also of immediate concern, given the lack of knowledge regarding status of their populations and the continuing existence of taxonomic uncertainties. In this study, we assess phylogenetic relationships for all recognized species and the majority of subspecies within the genus Gyps. The continuing veterinary use of diclofenac is an unknown but potential risk to related species with similar feeding habits to Gyps bengalensis. Therefore, an accurate assessment of the phylogenetic relationships among Gyps vultures should aid in their conservation by clarifying taxonomic uncertainties, and enabling inference of their respective relatedness to susceptible G. bengalensis. 相似文献2.
3.
Analysis of the cell envelopes of large numbers of bacterial strains is used for the epidemiological and taxonomic investigation of clinical, veterinarian, and ecological isolates. Isolation of cell envelopes requires lysis of the bacteria. We developed an apparatus to disrupt bacterial cells of 200 different isolates in suspension by ultrasonication automatically. It is composed of modified standard laboratory equipment (fraction collector, cooling unit, pump), a standard ultrasonifier, and a newly designed control unit, which includes a sampler. This apparatus was applied to the analysis of cell envelope proteins of 96 Haemophilus influenzae strains on sodium dodecyl sulfate-polyacrylamide gel electrophoresis within 3 days after the first culture. 相似文献
4.
5.
Growth of tumor cells with different sensitivities for murine natural killer cells in young and adult athymic nude mice 总被引:2,自引:0,他引:2
J C Romijn 《Experimental cell biology》1985,53(1):24-31
Of four tumor cell lines, the murine YAC lymphoma, the human K562 lymphoma, and the human prostatic carcinomas PC3 and PC93, the susceptibility to murine natural killer (NK) cells as well as the tumorigenicity in young (3.5-4 weeks old) and in adult (8-10 weeks old) nude mice were studied. In young nude mice, which exhibited a lower level of NK cell activity than adult nude mice, the formation of solid tumors after inoculation of tumor cell suspensions occurred more frequently and with a shorter time lag than in adult animals. These effects were observed not only with the NK-sensitive YAC cells, but also with the relatively NK-insensitive PC3 and PC93 cells, indicating that also factors other than NK cell susceptibility may influence the growth of tumor cells in nude mice. Therefore, the use of young nude mice may enhance the rate of success of heterotransplantation of human tumors, regardless of the NK cell susceptibility of the tumor cells. 相似文献
6.
7.
alpha 1-Proteinase inhibitor (alpha 1-PI), a member of the serine
proteinase inhibitor superfamily, has a primary role in controlling
neutrophil elastase activity within the mammalian circulation. Several
studies have indicated that the reactive center region of alpha 1-PI, the
amino acid sequence of which is critical to recognition of and binding to
target proteinases, is highly divergent within and among species. This
appears to be a consequence of accelerated rates of evolution that may have
been driven by positive Darwinian selection. In order to examine this and
other features of alpha 1-PI evolution in more detail, we have isolated and
sequenced cDNAs representing alpha 1- PI mRNAs of the mouse species Mus
saxicola and Mus minutoides and have compared these with a number of other
mammalian alpha 1-PI mRNAs. Relative to other mammalian mRNAs, the extent
of nonsynonymous substitution is generally high throughout the alpha 1-PI
mRNA molecule, indicating greater overall rates of amino acid substitution.
Within and among mouse species, the 5'-half of the mRNA, but not the
3'-half, has been homogenized by concerted evolution. Finally, the reactive
center is under diversifying or positive Darwinian selection in murid
rodents (rats, mice) and guinea pigs yet is under purifying selection in
primates and artiodactyls. The significance of these findings to alpha 1-PI
function and the possible selective forces driving evolution of serpins in
general are discussed.
相似文献
8.
Mitochondrial DNA polymorphisms in subterranean mole-rats of the Spalax ehrenbergi superspecies in Israel, and its peripheral isolates 总被引:1,自引:0,他引:1
Nevo E; Honeycutt RL; Yonekawa H; Nelson K; Hanzawa N 《Molecular biology and evolution》1993,10(3):590-604
Patterns of mitochondrial DNA (mtDNA) variation were examined in 133
mole-rats constituting all four chromosomal species (2n = 52, 2n = 54, 2n =
58, and 2n = 60) of the Spalax ehrenbergi superspecies in Israel, as well
as the peripheral isolates of 2n = 60. In the main range of the complex, a
total of 28 mtDNA haplotypes were found in 64 mole-rats, with most
haplotypes being unique to either a single chromosomal species or
population. mtDNA divergence increased from low to high diploid number in a
north-to-south direction in Israel. Overall levels of mtDNA diversity were
unexpectedly the highest in the 2n = 60, the youngest species of the
complex. The mtDNA haplotypes can be separated into two major groups, 2n =
52-54 and 2n = 58-60, and a phylogenetic analysis for each group revealed
evidence of a few haplotypes not sorted by diploid number. The overall
patterns of mtDNA divergence seen within and among the four chromosomal
species are consistent with the parapatric mode of speciation as suggested
from previous studies of allozyme and DNA hybridization. In a separate data
set the patterns of mtDNA variation were examined across the main
geographic range and across peripheral semi-isolates and isolates of the 2n
= 60 chromosomal species. Fifteen haplotypes were found in 69 mole-rats.
High levels of mtDNA diversity characterized the main range, semi-isolated,
and even some desert isolated populations. The peripheral isolates contain
much mtDNA diversity, including novel haplotypes.
相似文献
9.
A.F.L. Later E.F. Bruggemans F.P.H.T.M. Romijn J. van Pelt R.J.M. Klautz 《Cytokine》2013,61(2):438-444
PurposeAntifibrinolytics, used in cardiac surgery to abate postoperative blood loss, share anti-inflammatory properties by suppression of pro-inflammatory D-dimer and plasmin levels. Additional drug specific immune modulating qualities are often mentioned in the discussion on which antifibrinolytic can best be used. To determine the extent and relevance of these effects, we investigated cytokine and growth factor plasma levels in cardiac surgery patients randomized to receive either tranexamic acid, aprotinin, or placebo. Corticosteroid-treated patients served to put the effects in perspective.MethodsUsing a biochip immunoassay, plasma of 36 cardiac surgery patients was quantified for 12 cytokines and growth factors, assessed preoperatively and 6, 12, 24, and 48 h after the start of cardiopulmonary bypass. Eight patients were treated with tranexamic acid, nine with aprotinin, and nine received placebo. Ten placebo-treated patients received corticosteroids.ResultsIL-1ß, IL-6, IL-8, IL-10, IFN-γ, TNF-α, VEGF, MCP-1, and EGF plasma concentrations significantly changed over time across all patients. Aprotinin-treated patients showed decreased pro-inflammatory TNF-α and peak MCP-1 plasma levels when compared with placebo. However, corticosteroids attenuated the inflammatory response to a much larger extent, lowering postoperative IL-6, IL-10, IFN-γ, and VEGF concentrations also.ConclusionsAprotinin attenuates postoperative pro-inflammatory levels TNF-α and MCP-1 whereas tranexamic acid does not. The majority of plasma proteins studied, however, were not affected by the use of antifibrinolytics when compared with placebo. A clinically relevant common anti-inflammatory effect through inhibition of fibrinolysis seems therefore unlikely. 相似文献
10.
Janine J. Geerling Yanan Wang Louis M. Havekes Johannes A. Romijn Patrick C. N. Rensen 《PloS one》2013,8(2)