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1.
Positive selection is a general phenomenon in the evolution of abalone sperm lysin 总被引:36,自引:21,他引:15
Lysin is a 16kDa acrosomal protein used by abalone sperm to create a hole
in the egg vitelline envelope (VE). The interaction of lysin with the VE is
species-selective and is one step in the multistep fertilization process
that restricts heterospecific (cross-species) fertilization. For this
reason, the evolution of lysin could play a role in establishing prezygotic
reproductive isolation between species. Previously, we sequenced sperm
lysin cDNAs from seven California abalone species and showed that positive
Darwinian selection promotes their divergence. In this paper an additional
13 lysin sequences are presented representing species from Japan, Taiwan,
Australia, New Zealand, South Africa, and Europe. The total of 20 sequences
represents the most extensive analysis of a fertilization protein to date.
The phylogenetic analysis divides the sequences into two major clades, one
composed of species from the northern Pacific (California and Japan) and
the other composed of species from other parts of the world. Analysis of
nucleotide substitution demonstrates that positive selection is a general
process in the evolution of this fertilization protein. Analysis of
nucleotide and codon usage bias shows that neither parameter can account
for the robust data supporting positive selection. The selection pressure
responsible for the positive selection on lysin remains unknown.
相似文献
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P. D. Kim S. S. Zamay T. N. Zamay V. S. Prokopenko O. S. Kolovskaya G. S. Zamay V. Ya. Princ V. A. Seleznev A. I. Komonov E. A. Spivak R. Yu. Rudenko A. V. Dubinina A. V. Komarov V. V. Denisenko M. A. Komarova A. E. Sokolov A. A. Narodov V. P. Zjivaev A. S. Zamay 《Doklady. Biochemistry and biophysics》2016,466(1):66-69
Here we describe a method of forming large arrays (up to 109 pieces) of free magnetic Ni-nanodisks 50 nm thick coated on both sides with layers of 5 nm thick Au. The antitumor effect of the magnetic nickel gold-coated nanodisks and DNA aptamer conjugates was evaluated in vivo and in vitro. Under the influence of rotating magnetic field, the studied nanodisks can cause the death of Ehrlich ascites carcinoma cells. 相似文献
5.
Nonequilibrium statistical models of the active transport of ions in biomembranes have been constructed. Differences of chemical potentials of the ATP-ADP reaction and the electrochemical potential of ions were taken as the thermodynamic forces responsible for the flow of ions through the membrane. The active transport of ions was viewed as a cross phenomenon arising from the chemical reaction of the ATP hydrolysis. These models provide independent calculations of the resting potential at the biomembrane and concentrations of ions in a cell on the assumption the free energy of the ATP-ADP reaction is fully (without the dissipation loss) converted to the free energy of transported ions. They take into account the presence of nonpenetrating ions in a cell. It was shown that different concentrations of nonpenetrating ions have a considerable effect on the resting potential. The proposed models were compared with experimental data obtained for different types of cells including neurons, muscular cells, bacteria, plants, and mitochondria. Calculated values of the membrane potential and ion concentrations were in good qualitative agreement with experimental data. 相似文献
6.
A statistical model of active ion transport in biomembranes was developed. The model makes it possible to calculate both the value of membrane potential phi zero and the rate of ion concentrations inside and outside the cell. These values depend on the difference of chemical potentials of the ATP-ADP system and the permeability of the biomembrane for ions being transported. The calculated phi zero value approximately 200-250 mV is consistent with the data on proton pumps. 相似文献
7.
The level of chromosome aberrations induced by mitomycin C and cytosine arabinoside in the cultured lymphocytes from patients with chronic alcoholism is elevated, as compared to that observed in the cultured lymphocytes of healthy persons. A supposition was made that transitory instability of cell genome could cause this phenomenon. 相似文献
8.
It was demonstrated that human and horse hemoglobin variants having quantitative difference in the interaction with dipalmitoyllecithin exhibit features of generality. The latter is manifested in the established hydrophobic contacts between protein and lipid in hydrated films discovered by IR spectroscopy. The arrangement of hydrophobicity profiles of hemoproteins demonstrated in amino acid sequences of chains the existence of intermittent hydrophobic and hydrophilic regions. Such a composition of hemoglobins could underlie their property to participate in hydrophobic interactions with lipids. 相似文献
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At present a concept prevails that pathological alterations in insect hosts infected with microsporidia, and those associated with hormone imbalance may be explained by the production of juvenile hormone-like (JH) substances by microsporidia. According to another view point, this pathology is a consequence of the host response. We suggested that the microsporidian infection can provoke a stress reaction in insects, which may cause JH secretion by these insects. To confirm this hypothesis, we have analysed major stress protein Hsp70 levels in the infected insects. Using affinity chromatography on ATP-agarose and immunoblotting, we have shown that Hsp70 was accumulated in infected crickets, and that it was the host protein. The consequence of events accompanying the infection in the insects is discussed in relation to the response of hormonal system of the host organism. 相似文献