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131.
Background
Intoxication from the psychostimulant methamphetamine (METH) because of cardiovascular collapse is a common cause of death within the abuse population. For obvious reasons, the heart has been taken as the primary target for this METH-induced toxicity. The demonstration that failure of brain stem cardiovascular regulation, rather than the heart, holds the key to cardiovascular collapse induced by the pesticide mevinphos implicates another potential underlying mechanism. The present study evaluated the hypothesis that METH effects acute cardiovascular depression by dampening the functional integrity of baroreflex via an action on brain stem nuclei that are associated with this homeostatic mechanism. 相似文献132.
133.
Charles D Criscione Claudia LL Valentim Hirohisa Hirai Philip T LoVerde Timothy JC Anderson 《Genome biology》2009,10(6):R71-13
Background
Schistosoma mansoni is a blood fluke that infects approximately 90 million people. The complete life cycle of this parasite can be maintained in the laboratory, making this one of the few experimentally tractable human helminth infections, and a rich literature reveals heritable variation in important biomedical traits such as virulence, host-specificity, transmission and drug resistance. However, there is a current lack of tools needed to study S. mansoni's molecular, quantitative, and population genetics. Our goal was to construct a genetic linkage map for S. mansoni, and thus provide a new resource that will help stimulate research on this neglected pathogen. 相似文献134.
Re: Phylogenetic relationships in Sphingidae (Insecta: Lepidoptera): initial evidence from two nuclear genes 总被引:2,自引:0,他引:2
Regier JC Mitter C Friedlander TP Peigler RS 《Molecular phylogenetics and evolution》2001,19(2):311-316
Partial DNA sequences from two mitochondrial (mt) and one nuclear gene (cytochrome b, 12S rRNA, and C-mos) were used to estimate the phylogenetic relationships among the six extant species of skinks endemic to the Cape Verde Archipelago. The species form a monophyletic unit, indicating a single colonization of the islands, probably from West Africa. Mabuya vaillanti and M. delalandii are sister taxa, as indicated by morphological characters. Mabuya fogoensis and M. stangeri are closely related, but the former is probably paraphyletic. Mabuya spinalis and M. salensis are also probably paraphyletic. Within species, samples from separate islands always form monophyletic groups. Some colonization events can be hypothesized, which are in line with the age of the islands. C-mos variation is concordant with the topology derived from mtDNA. 相似文献
135.
136.
Statistical methods of DNA sequence analysis: detection of intragenic recombination or gene conversion 总被引:32,自引:4,他引:28
Simple but exact statistical tests for detecting a cluster of associated
nucleotide changes in DNA are presented. The tests are based on the linear
distribution of a set of s sites among a total of n sites, where the s
sites may be the variable sites, sites of insertion/deletion, or
categorized in some other way. These tests are especially useful for
detecting gene conversion and intragenic recombination in a sample of DNA
sequences. In this case, the sites of interest are those that correspond to
particular ways of splitting the sequences into two groups (e.g., sequences
A and D vs. sequences B, C, and E-J). Each such split is termed a
phylogenetic partition. Application of these methods to a well-documented
case of gene conversion in human gamma-globin genes shows that sites
corresponding to two of the three observed partitions are significantly
clustered, whereas application to hominoid mitochondrial DNA
sequences--among which no recombination is expected to occur--shows no
evidence of such clustering. This indicates that clustering of
partition-specific sites is largely due to intragenic recombination or gene
conversion. Alternative hypotheses explaining the observed clustering of
sites, such as biased selection or mutation, are discussed.
相似文献
137.
The nucleotide sequences of the cow epsilon 2 and epsilon 4 globin genes
were determined. The sequences were 95% identical. These genes arose via a
four-gene block duplication that also gave rise to the bovine fetal (gamma)
and adult (beta) genes. Their deduced amino acid sequences are unlike any
previously reported fetal or adult globins; rather, comparison to other
mammalian globin genes indicates that they are embryonic in nature. The
sequence data indicate that these two genes have converted each other
during evolution. Pairwise comparison to the corresponding goat genes shows
greater similarity between paralogues than between more directly related
orthologues. This is in direct contrast to the situation between the cow
and goat fetal and adult genes. These observations suggest that the
frequency of DNA conversion or the fixation of conversion events may vary
in different locations of the cow beta-globin cluster.
相似文献
138.
139.
We described the organization of two silkmoth chorion genes, called E1 and E2, whose expression is largely restricted in time to the very late period of choriogenesis and in space to one of two major subpopulations of follicle cells. Using E1 and E2 clone cDNAs as probes, we showed that gene copy numbers per haploid genome remain constant throughout silkmoth development despite major changes in total DNA content per nucleus. Furthermore, gene copy numbers are the same in both cellular regions of the choriogenic follicle despite differences in nuclear size and levels of E gene expression. Southern analysis indicated between two and four copies each for E1 and E2 genes. Analysis of chromosomal clones showed that single copies of E1 and E2 are separated by about 7.5 kilobases and are transcribed from the same DNA strand. Two distinct pairs of cloned E1 and E2 genes were characterized. No other chorion genes were in their immediate vicinity. 相似文献
140.