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1.
A comparative description of mitochondrial DNA differentiation in selected avian and other vertebrate genera 总被引:14,自引:1,他引:13
Levels of mitochondrial DNA (mtDNA) sequence divergence between species
within each of several avian (Anas, Aythya, Dendroica, Melospiza, and
Zonotrichia) and nonavian (Lepomis and Hyla) vertebrate genera were
compared. An analysis of digestion profiles generated by 13-18 restriction
endonucleases indicates little overlap in magnitude of mtDNA divergence for
the avian versus nonavian taxa examined. In 55 interspecific comparisons
among the avian congeners, the fraction of identical fragment lengths (F)
ranged from 0.26 to 0.96 (F = 0.46), and, given certain assumptions, these
translate into estimates of nucleotide sequence divergence (p) ranging from
0.007 to 0.088; in 46 comparisons among the fish and amphibian congeners, F
values ranged from 0.00 to 0.36 (F = 0.09), yielding estimates of P greater
than 0.070. The small mtDNA distances among avian congeners are associated
with protein-electrophoretic distances (D values) less than approximately
0.2, while the mtDNA distances among assayed fish and amphibian congeners
are associated with D values usually greater than 0.4. Since the
conservative pattern of protein differentiation previously reported for
many avian versus nonavian taxa now appears to be paralleled by a
conservative pattern of mtDNA divergence, it seems increasingly likely that
many avian species have shared more recent common ancestors than have their
nonavian taxonomic counterparts. However, estimates of avian divergence
times derived from mtDNA- and protein-calibrated clocks cannot readily be
reconciled with some published dates based on limited fossil remains. If
the earlier paleontological interpretations are valid, then protein and
mtDNA evolution must be somewhat decelerated in birds. The empirical and
conceptual issues raised by these findings are highly analogous to those in
the long-standing debate about rates of molecular evolution and times of
separation of ancestral hominids from African apes.
相似文献
2.
Olga R. Yamilova Ilya V. Martynov Allison S. Brandvold Irina V. Klimovich Alex H. Balzer Alexander V. Akkuratov Ilya E. Kusnetsov Natalie Stingelin Pavel A. Troshin 《Liver Transplantation》2020,10(7)
In view of a rapid development and increase in efficiency of organic solar cells, reaching their long‐term operational stability represents now one of the main challenges to be addressed on the way toward commercialization of this photovoltaic technology. However, intrinsic degradation pathways occurring in organic solar cells under realistic operational conditions remain poorly understood. The light‐induced dimerization of the fullerene‐based acceptor materials discovered recently is considered to be one of the main causes for burn‐in degradation of organic solar cells. In this work, it is shown that not only the fullerene derivatives but also different types of conjugated polymers and small molecules undergo similar light‐induced crosslinking regardless of their chemical composition and structure. In the case of conjugated polymers, crosslinking of macromolecules leads to a rapid increase in their molecular weight and consequent loss of solubility, which can be revealed in a straightforward way by gel permeation chromatography analysis via a reduction/loss of signal and/or smaller retention times. Results of this work, thus, shift the paradigm of research in the field toward designing a new generation of organic absorbers with enhanced intrinsic photochemical stability in order to reach practically useful operation lifetimes required for successful commercialization of organic photovoltaics. 相似文献
3.
Sommer F Awazu S Anton-Erxleben F Jiang D Klimovich AV Klimovich BV Samoilovich MP Satou Y Krüss M Gelhaus C Kürn U Bosch TC Khalturin K 《Molecular biology and evolution》2012,29(10):3081-3093
Adaptive immune systems are present only in vertebrates. How do all the remaining animals withstand continuous attacks of permanently evolving pathogens? Even in the absence of adaptive immunity, every organism must be able to unambiguously distinguish "self" cells from any imaginable "nonself." Here, we analyzed the function of highly polymorphic gene vCRL1, which is expressed in follicle and blood cells of Ciona intestinalis, pointing to possible recognition roles either during fertilization or in immune reactions. By using segregation analysis, we demonstrate that vCRL1 locus is not involved in the control of self-sterility. Interestingly, genetic knockdown of vCRL1 in all tissues or specifically in hemocytes results in a drastic developmental arrest during metamorphosis exactly when blood system formation in Ciona normally occurs. Our data demonstrate that vCRL1 gene might be essential for the establishment of a functional blood system in Ciona. Presumably, presence of the vCRL1 receptor on the surface of blood cells renders them as self, whereas any cell lacking it is referred to as nonself and will be consequently destroyed. We propose that individual-specific receptor vCRL1 might be utilized to facilitate somatic self/nonself discrimination. 相似文献
4.
V. B. Klimovich M. P. Samoilovich B. V. Klimovich 《Journal of Evolutionary Biochemistry and Physiology》2008,44(2):151-166
Molecules of secretory immunoglobulins (Ig) of classes A and M (sIgA and sIgM) play the main role in protection of mucosae from pathogenic factors. The apparatus of synthesis of these molecules represent the most powerful part of the immune system. One of the key elements of the sIgA and sIgM is J-chain. It represents an acid polypeptide of molecular mass of about 15 kDa composed of 137 amino acid residues including 8 cysteine residues and one site of N-glycosylation. The primary structure of the J-chain is unique: attempts to ascribe it to any family of known proteins so far have failed. The J-chain is inserted into the sIgA and sIgM molecules by forming disulfide bonds with C-terminal sites of α-or μ-chains. It is necessary for formation of IgA dimers and IgM pentamers, for reception of these molecules by epithelial cells, binding of secretory component to them, and for transfer of sIgA and sIgM molecules onto mucosal surfaces and into secrets of exocrine glands. The J-chain has been revealed in the cytoplasm of the early T-and B-lymphocyte precursors not producing Ig. The J-chain is detected in the human embryonic liver cells earlier than the expression of the μ-chain gene begins. Study of mice with knockout of J-chain B-lymphocytes-producers has shown their block of functions of T-helpers providing formation of immunologic memory. Comparison of J-chain genes of mammals, amphibians, reptiles, and cartilaginous fishes has shown the degree of interspecies homology of these proteins to vary from 33% to 70%. The J-chain genes were revealed in representatives of all vertebrate classes except for cyclostomes and bony fishes. In 1996, data were published about the presence of the J-chain genes-homologs in invertebrates, tunicates, and cyclostomes. No papers reproducing or confirming these data have been published. On the contrary, in the literature an opinion appeared that indicate necessity to revise the notion about the presence of J-chain in invertebrates. The main unsolved issues on the J-chain involve the tertiary structure of this protein, its relation to some particular protein family, its functions in cells of the T-and B-lymphocytic differentiation lineages as well as its evolutionary age. 相似文献
5.
M. P. Samoilovich S. G. Kuznetsov M. S. Pavlova V. B. Klimovich 《Journal of Evolutionary Biochemistry and Physiology》2001,37(4):348-357
The goal of the study was to obtain a panel of monoclonal antibodies (MAb) against antigens of freshwater polyps of the genus Hydra. Hybrid mice F1(Balb/c × SJL/J) were immunized with cell membrane fraction of H. vulgaris and three months later their splenocytes were fused with cultured mouse myeloma cells 653A. Testing of culture fluids in ELISA with immobilized H. vulgaris cells, 82 hybridomas producing MAb were revealed. Study of MAb specificity in ELISA with H. vulgaris and H. oligactis cells indicated that 22% of them recognized only H. vulgaris antigens. About 50% of MAb recognized equally antigens of the both species. The rest of MAb reacted with H. vulgaris and H. oligactis antigens to different degree. Eight hybridomas producing MAb of all three above groups were adapted for growth as ascitic tumors. The distribution of antigens binding these MAb was studied in indirect immunofluorescence on fixed polyps, living or fixed cells, and on paraffin- embedded sections. Among the best studied MAb, of the greatest interest were the following reagents. One of them (1A10) revealed an antigen on surface membranes of ectodermal epithelial cells of H. vulgaris. The second one (1G10) was specific of the antigen located in mesoglea and basal cytoplasmic areas of ectodermal and entodermal epithelial cells of the both hydra species. The MAb 4G3 interacted with cytoplasmic antigen of ectodermal epithelia-muscular cells of the both hydra species. MAb 4H1 revealed nematocytes in H. vulgaris and H. oligactis. The data obtained indicate that in two species of hydra the epitopes binding the same MAb might be located in cells of different types. 相似文献
6.
7.
We studied different genetic models and evaluation systems to select against a genetic disease with additive, recessive or polygenic inheritance in genetic conservation schemes. When using optimum contribution selection with a restriction on the rate of inbreeding (ΔF) to select against a disease allele, selection directly on DNA-genotypes is, as expected, the most efficient strategy. Selection for BLUP or segregation analysis breeding value estimates both need 1–2 generations more to halve the frequency of the disease allele, while these methods do not require knowledge of the disease mutation at the DNA level. BLUP and segregation analysis methods were equally efficient when selecting against a disease with single gene or complex polygene inheritance, i.e. knowledge about the mode of inheritance of the disease was not needed for efficient selection against the disease. Smaller schemes or schemes with a more stringent restriction on ΔF needed more generations to halve the frequency of the disease alleles or the fraction of diseased animals. Optimum contribution selection maintained ΔF at its predefined level, even when selection of females was at random. It is argued that in the investigated small conservation schemes with selection against a genetic defect, control of ΔF is very important. 相似文献
8.
The first mollusc mRNA coding G-protein-coupled transmembrane receptor (GPСR), homologous to human receptors LUSTR 1 (GPR107) and LUSTR 2 (GPR108), was isolated from haemocytes of common periwinkle Littorina littorea. The analyses showed that the full-length cDNA is 1935 bp long and is predicted to encode a 614 amino acid protein (named Lit-LUSTR) with a calculated molecular mass of 69.6 kDa and theoretical isoelectric point 7.59. Pair-wise comparisons between Lit-LUSTR and LUSTR proteins from human or mouse have approximately 38% identity and 56% similarity. Lit-LUSTR clusters with LUSTR-A sub-family proteins and is a first characterization of proteins containing Lung7TM-R domain in Mollusca. Significant differences were found between the Lit-LUSTR mRNA levels in haemocytes of healthy periwinkles and those naturally infected with the echinostome trematode Himasthla elongata. Down regulated expression of the LUSTR-like receptor caused by infection illustrates modification of the haemocyte receptor system and may be attributed to the previously demonstrated greater numbers of “immature” haemocytes in the circulation of infected snails. 相似文献
9.
A.?M.?Popov A.?N.?OsipovEmail author E.?A.?Korepanova O.?N.?Krivoshapko A.?A.?Artyukov A.?A.?Klimovich 《Biophysics》2017,62(3):407-414
Echinochrome A (6-ethyl-2,3,5,7,8-pentahydroxy-1,4-naphthoquinone) isolated from the body of sand dollar Scaphechinus mirabilis is an active substance of cardioprotective medication Histochrome and exerts a wide spectrum of anti-inflammatory activities. In the present paper, we conducted a comparative study of the antioxidant (radical-scavengering) properties of echinochrome A in 2,2′-azobis(2-methylpropionamidine) dihydrochloride?luminol and hemoglobin?hydrogen peroxide?luminol systems and assessed its impact on permeability of planar bilayer lipid membranes. Trolox was used as a reference antioxidant and ascorbic acid and dihydroquercetin are taken as standards. Echinochrome A shows moderate antioxidant activity, possessing higher antioxidant capacity than Trolox and ascorbic acid, but exhibiting lower antioxidant potential compared with dihydroquercetin in tests for antioxidant activity in both investigated systems. The test substances can be arranged in the following order according to the effectiveness of the antioxidant effect: dihydroquercetin > echinochrome A > Trolox > ascorbic acid. Echinochrome A does not lead to significant changes in the permeability of planar bilayer membranes in a dose range of 1.5 to 30 μМ. Our data indicate that echinochrome A has a rather high level of radical-scavengering activity without a primary membranotropic effect. It is thought that the high levels of the cardioprotective and anti-inflammatory activities of echinochrome A may be due not only to the ability of this substance to neutralize reactive oxygen species, but also to its capacity to generate physiological concentrations of hydrogen peroxide molecules in biological systems as signaling messengers of various metabolic processes and biochemical pathways. The suspected mechanisms of the biological activity of echinochrome A are discussed. 相似文献
10.
A. A. Ayzenshtadt N. A. Ivanova V. V. Bagaeva A. B. Smolyaninov A. A. Pinevich M. P. Samoylovich V. B. Klimovich 《Cell and Tissue Biology》2014,8(3):193-197
The data concerning the influence of mesenchymal stromal cells (MSCs) on immunoglobulin (Ig) production are contradictory. Most results were obtained using MSC derived from bone marrow. The properties of MSCs obtained from other tissues are not well studied. In the present work, MSC cultures have been established from umbilical cord, adipose tissue, and bone marrow of healthy donors, as well as from bone marrow of patients with autoimmune diseases. MSCs from all these sources exhibited similar surface markers. We assayed the influence of MSC cocultivation at exponential or stationary growth phases on IgM content in Namalva and IgE content in U266 cells. Bone marrow MSCs from healthy donors did not affect IgM and IgE production. Proliferating MSCs from patients with Crohn’s disease and multiple sclerosis stimulated Ig production. Exponentially growing MSCs derived from umbilical cord and adipose tissue also stimulated Ig synthesis. MSCs at stationary cultures enhanced IgM production in Namalva (cells) and suppressed IgE synthesis in U266 cells. Thus, MSCs from various tissues with common phenotypes differed in their capacity to modulate Ig production by B-lymphoid cells. The effect of MSCs depends on their growth stage and may be different for lymphoblastoid and myeloma cells. 相似文献