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排序方式: 共有173条查询结果,搜索用时 15 毫秒
1.
One hundred nineteen pen-raised wild turkeys (Meleagris gallopavo) from 12 locations in nine states in the United States were examined for coccidia by sugar flotation of intestinal contents and mucosa or by subinoculating the contents into uninfected domestic turkeys. Seventy-eight (66%) of the turkeys were positive for coccidia. There were no differences in the frequency of coccidia among adult, sub-adult or juvenile turkeys. More females (75%) were infected than males (48%). The species of coccidia from 30 of the turkeys were identified based on microscopic examination of oocysts, fresh scrapings, stained sections and inoculations of bobwhites (Colinus virginianus). The frequency of each species was Eimeria meleagrimitis (97%), E. gallopavonis (47%), E. meleagridis (27%), E. dispersa (17%), E. innocua-E. subrotunda (13%), E. adenoeides (7%) and an undescribed species (3%). Of the 30 turkeys in which the species of coccidia was determined, 30% had a single species infection, 40% had two species, 20% had three species and 10% had four species. 相似文献
2.
3.
The results of surveillance for hog cholera (HC) in wild swine (Sus scrofa) collected from throughout the United States from 1979 to 1987 are presented. Sera collected from 1,218 wild swine and tissues from 637 were evaluated for HC antibodies and virus, respectively. Included within this surveillance were samples from Santa Cruz and Santa Rosa Islands, California, where HC virus had been deliberately introduced into wild swine during the 1950's in attempts to eradicate these animals. All evaluations were considered negative for HC. It appears that the HC virus does not maintain itself in dispersed swine populations and that wild swine have not remained a reservoir of HC since its eradication in domestic swine in the United States. 相似文献
4.
J Hadidian S R Jenkins D H Johnston P J Savarie V F Nettles D Manski G M Baer 《Journal of wildlife diseases》1989,25(1):1-9
In summer 1986, a study was conducted to evaluate raccoon (Procyon lotor) acceptance of oral baits that could be used for rabies vaccination. One thousand wax-coated sponge bait cubes were filled with 5 mg of a seromarker (iophenoxic acid), placed in polyethylene bags, and hand-distributed in an 80 ha area within an urban National Park in Washington, D. C. (USA). After 3 wk, target and nontarget animals were trapped and blood samples collected to evaluate bait uptake. Thirty-three of 52 (63%) raccoons had elevated blood iodine levels indicating they had eaten at least one bait, 13 (25%) were negative, and six (12%) had marginal values. These results indicate that sponge baits hand-placed at a density of 12.4/ha can reach a significant proportion of an urban raccoon population. Implications for oral rabies vaccination of raccoons are discussed. 相似文献
5.
An update is presented on the distribution of the meningeal worm (Parelaphostrongylus tenuis) of white-tailed deer (Odocoileus virginianus) in the southeastern United States. The parasite is widely distributed and common in all or much of Arkansas, Kentucky, Louisiana, Maryland, North Carolina, Tennessee, Virginia and West Virginia. It is also common in the northern half of Alabama and Georgia. In contrast, it is rare or absent along the Atlantic and Gulf coastal plains of Alabama, Georgia, Mississippi and South Carolina. It has been collected from a single deer in Florida. 相似文献
6.
MAJOR CLADES OF THE ANGIOSPERMS 总被引:2,自引:0,他引:2
ROLF DAHLGREN KÅRE BREMER 《Cladistics : the international journal of the Willi Hennig Society》1985,1(4):349-368
Abstract— Our knowledge of fundamental angiosperm interrelationships is still very incomplete. The absence of a narrowly circumscribed gymnosperm outgroup, ideally the sister group, makes character evaluation, necessary for a cladistic analysis, difficult. According to current views the superorder Magnoliiflorae with a number of other groups, for example the monocotyledons, may represent a complex of families near the base of the angiosperms. Interrelationships of groups within the monocotyledons are much better understood than those between groups within the dicotyledons. A cladogram of monocotyledon orders based on earlier work by R. Dahlgren, H. T. Clifford, and F. N. Rasmussen is presented. A data matrix for a sample of the angiosperms with 61 characters for 49 taxa, mostly magnoliifloran and related families, is presented. The characters are polarized mainly according to the current view that the primitive angiosperm morphotype is a woody dicotyledon with strobiloid flowers. As an alternative the matrix is adjusted following W. C. Burger's conjecture that the primitive angiosperm was a herbaceous monocotyledon with trimerous flowers. Both matrices were run in a computerized parsimony analysis, resulting in numerous equally parsimonious solutions. This result is illustrative of the great homoplasy in the available character information, and also of how little actually is known about fundamental angiosperm interrelationships or phylogeny. 相似文献
7.
Assignment of orthologous relationships among mammalian alpha-globin genes by examining flanking regions reveals a rapid rate of evolution 总被引:1,自引:0,他引:1
In order to study the relationships among mammalian alpha-globin genes, we
have determined the sequence of the 3' flanking region of the human alpha 1
globin gene and have made pairwise comparisons between sequenced
alpha-globin genes. The flanking regions were examined in detail because
sequence matches in these regions could be interpreted with the least
complication from the gene duplications and conversions that have occurred
frequently in mammalian alpha-like globin gene clusters. We found good
matches between the flanking regions of human alpha 1 and rabbit alpha 1,
human psi alpha 1 and goat I alpha, human alpha 2 and goat II alpha, and
horse alpha 1 and goat II alpha. These matches were used to align the
alpha-globin genes in gene clusters from different mammals. This alignment
shows that genes at equivalent positions in the gene clusters of different
mammals can be functional or nonfunctional, depending on whether they
corrected against a functional alpha-globin gene in recent evolutionary
history. The number of alpha-globin genes (including pseudogenes) appears
to differ among species, although highly divergent pseudogenes may not have
been detected in all species examined. Although matching sequences could be
found in interspecies comparisons of the flanking regions of alpha- globin
genes, these matches are not as extensive as those found in the flanking
regions of mammalian beta-like globin genes. This observation suggests that
the noncoding sequences in the mammalian alpha-globin gene clusters are
evolving at a faster rate than those in the beta-like globin gene clusters.
The proposed faster rate of evolution fits with the poor conservation of
the genetic linkage map around alpha-globin gene clusters when compared to
that of the beta-like globin gene clusters. Analysis of the 3' flanking
regions of alpha-globin genes has revealed a conserved sequence
approximately 100-150 bp 3' to the polyadenylation site; this sequence may
be involved in the expression or regulation of alpha-globin genes.
相似文献
8.
INTRODUCTI0NThedifferentiati0nofcelIsalongthemonocyte-macr0phagepathwayandthesig-nalsinvo1vedinthesecel1sacquiringtheabilitytokilltum0rcellsarenotfllllyundersto0d.Wehavebeenstudingamoleculewhichappearst0beanimportantmemberofthecytokinenetworkinvo1vedintheregulati0nmonocyteactivation.ThiscytokinetermedP48wasisolatedfr0mthehllmannullcellleukemiacell1ineReh.IthasbeenpurifiedtohomogeneityandfOundtobedistinctfrominterferongamma,col0nystimulatingfactors(CSFs)andTNFalphaalldbeta[1,2].Func-ti… 相似文献
9.
Chronic debilitation and anemia were observed in a free-living opossum (Didelphis marsupialis) heavily parasitized by Physaloptera turgida, Brachylaima virginianum, and Cruzia americana. Chronic interstitial pneumonia associated with Capillaria aerophila and a metastrongyloid nematode also was present. 相似文献
10.
Under natural conditions, plants are subjected to continuous changes of irradiance that drive variations of stomatal conductance to water vapour (gs). We propose a dynamic model to predict the temporal response of gs at the leaf level using an asymmetric sigmoid function with a unique parameter describing time constants for increasing and decreasing gs. The model parameters were adjusted to observed data using Approximate Bayesian Computation. We tested the model performance for (1) instant changes of irradiance; or (2) continuous and controlled variations of irradiance simulating diurnal time courses. Compared with the two mostly used steady‐state models, our dynamic model described daily time courses of gs with a higher accuracy. In particular, it was able to describe the hysteresis of gs responses to increasing/decreasing irradiance and the resulting rapid variations of intrinsic water‐use efficiency. Compared to the mechanistic model of temporal responses of gs by Kirschbaum, Gross & Pearcy, for which time constants were estimated with a large variance, our model estimated time constants with a higher precision. It is expected to improve predictions of water loss and water‐use efficiency in higher scale models by using a small number of parameters. 相似文献