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1.
2.
Spatial restriction of AChR gene expression to subsynaptic nuclei. 总被引:21,自引:0,他引:21
3.
mtDNA diversity in rhesus monkeys reveals overestimates of divergence time and paraphyly with neighboring species 总被引:4,自引:0,他引:4
Reconstructions of the human-African great ape phylogeny by using
mitochondrial DNA (mtDNA) have been subject to considerable debate. One
confounding factor may be the lack of data on intraspecific variation. To
test this hypothesis, we examined the effect of intraspecific mtDNA
diversity on the phylogenetic reconstruction of another Plio- Pleistocene
radiation of higher primates, the fascicularis group of macaque (Macaca)
monkey species. Fifteen endonucleases were used to identify 10 haplotypes
of 40-47 restriction sites in M. mulatta, which were compared with similar
data for the other members of this species group. Interpopulational,
intraspecific mtDNA diversity was large (0.5%- 4.5%), and estimates of
divergence time and branching order incorporating this variation were
substantially different from those based on single representatives of each
species. We conclude that intraspecific mtDNA diversity is substantial in
at least some primate species. Consequently, without prior information on
the extent of genetic diversity within a particular species, intraspecific
variation must be assessed and accounted for when reconstructing primate
phylogenies. Further, we question the reliability of hominoid mtDNA
phylogenies, based as they are on one or a few representatives of each
species, in an already depauperate superfamily of primates.
相似文献
4.
Dr. Jack E. Brinn Hubert W. Burden Michael R. Schweisthal 《Cell and tissue research》1977,182(1):133-138
Summary The fetal rat pancreas, explanted at 18 days of gestation and cultured up to ten days, contains numerous acetylcholinesterase-positive neurons. These nerves usually appear in small ganglia although single nerve cells are encountered. The axons of these intrapancreatic nerves appear to terminate only in the islet tissue and not on any exocrine components of the expiant. It is concluded that the fetal rat pancreas contains an islet-specific group of cholinergic neurons.We gratefully acknowledge the skilled technical assistance of Dan Whitehead and the secretarial assistance of Mary Pat Brady 相似文献
5.
We have shown previously that dystrophin is a component of postsynaptic membranes in Torpedo electric organ and is localized at mammalian neuromuscular synapses. In skeletal muscle, dystrophin is also detectable at the non-synaptic membrane of the myofiber, whereas in the electric organ, dystrophin is strictly localized to the postsynaptic membrane, and is not detectable in non-synaptic membranes. Multiple isoforms of dystrophin are present in skeletal muscle, and different isoforms could potentially be targetted to synaptic and non-synaptic membranes. We sought to determine whether the electric organ contains a single, or multiple isoforms of dystrophin, and we show here that the electric organ contains both a and b isoforms of dystrophin. Because dystrophin is found only at the postsynaptic membrane of the electric organ, we conclude that the two isoforms coexist in the postsynaptic membrane. 相似文献
6.
A D MacNicoll P M Burden H Rattle P L Grover P Sims 《Chemico-biological interactions》1979,27(2-3):365-379
The formation of trans-dihydrodiols from dibenz[a,c]anthracene, dibenz[a,h]anthracene and chrysene by chemical oxidation in an ascorbic acid-ferrous sulphate-EDTA system and by rat-liver microsomal fractions has been studied using a combination of thin-layer (TLC) and high pressure liquid chromatography (HPLC) to separate the mixtures of isomeric dihydrodiols. The 1,2- and 3,4-dihydrodiols of dibenz[a,c]anthracene, the 1,2-,3,4- and 5,6-dihydrodiols of dibenz[a,h]anthracene and the 1,2-, 3,4- and 5,6-dihydrodiols of chrysene were formed in chemical oxidations. These dihydrodiols were also formed when the three parent hydrocarbons were metabolized by rat-liver microsomal fractions and, in addition, dibenz[a,c]anthracene yielded the 10,11-dihydrodiol. The 1,2- and 3,4-dihydrodiols of dibenz[a,c]anthracene have not been reported previously either as metabolites of the hydrocarbon or as products of chemical syntheses and the 5,6-dihydrodiol of chrysene was not detected in earlier metabolic studies. 相似文献
7.
Abdominal vagotomy on Day 8 of pregnancy in rats decreased the number of live fetuses at Day 16 and increased the number of resorbing fetuses. The activity of delta5-3beta-hydroxysteroid dehydrogenase (3beta-HSD) in the corpus luteum and interstitial gland, LH and progesterone values in plasma and progesterone values in ovarian tissue were all lower in vagotomized rats than in sham-operated controls. Ovarian PGF levels were not affected. We suggest that these effects were caused by a direct effect of vagotomy on LH secretion which in turn lowers 3beta-HSD activity and progesterone levels in ovarian tissue and plasma, leading to fetal resorption. 相似文献
8.
Andrew Harrison Hans Binder Arnaud Buhot Conrad J. Burden Enrico Carlon Cynthia Gibas Lara J. Gamble Avraham Halperin Jef Hooyberghs David P. Kreil Rastislav Levicky Peter A. Noble Albrecht Ott B. Montgomery Pettitt Diethard Tautz Alexander E. Pozhitkov 《Nucleic acids research》2013,41(5):2779-2796
Hybridization of nucleic acids on solid surfaces is a key process involved in high-throughput technologies such as microarrays and, in some cases, next-generation sequencing (NGS). A physical understanding of the hybridization process helps to determine the accuracy of these technologies. The goal of a widespread research program is to develop reliable transformations between the raw signals reported by the technologies and individual molecular concentrations from an ensemble of nucleic acids. This research has inputs from many areas, from bioinformatics and biostatistics, to theoretical and experimental biochemistry and biophysics, to computer simulations. A group of leading researchers met in Ploen Germany in 2011 to discuss present knowledge and limitations of our physico-chemical understanding of high-throughput nucleic acid technologies. This meeting inspired us to write this summary, which provides an overview of the state-of-the-art approaches based on physico-chemical foundation to modeling of the nucleic acids hybridization process on solid surfaces. In addition, practical application of current knowledge is emphasized. 相似文献
9.
10.
Journal of Mathematical Biology - The stationary distribution of a sample taken from a Wright–Fisher diffusion with general small mutation rates is found using a coalescent approach. The... 相似文献