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At least 343 records · Page 19Linked to original sources
PubMedDate not supplied

[Effect of thermal acclimation on the expression of gene coding for lactate dehydrogenase A4 in loach skeletal muscle].

Acclimation of Misgurnus fossilis to 5 and 18 degrees C induced considerable changes in LDH-A gene expression in white skeletal muscle. Qualities of total and messenger RNA isolated from weighted portions of muscle are considerably higher after acclimation to 18 degrees C as compared to 5 degrees C. However, a PCR assay of cDNA synthesized from these mRNA and equalized by optical density demonstrated that the level of LDH-A gene expression was indistinguishable for high and low acclimation temperatures, while expression of other genes (glyceraldehyde-3-phosphate dehydrogenase and alpha-actin) considerably increased at 18 degrees C as compared to 5 degrees C. The specific enzymatic activity of LDH from white skeletal muscle of the fish acclimated to low temperature is by 20% higher than that for high-temperature acclimation. Structural analysis of the PCR products synthesized on cDNA-5 degrees C and cDNA-18 degrees C has revealed no differences. However, there are indirect indications of the differences in the C-thermal region of the LDH-A molecule. Northern hybridization reveals the differences at the RNA level: one (1400 bp) or two (about 1600 and 1400 bp) hybridization signals have been found in mRNA-5 degrees C and mRNA-18 degrees C, respectively. The presence of two fractions in the mRNA-18 degrees C indicates alternative splicing.

Adaptation, Physiological↗
PubMedDate not supplied

[The peculiarities of repair DNA-polymerases in the loach embryogenesis].

The current concept of eukaryotic DNA polymerases is considered, which are involved in nuclear DNA repair. The data are given on a new group of DNA polymerases that maintain the integrity of DNA structures without preliminary excision of damaged regions. A special attention is paid to specific features of the functioning of repair DNA polymerases in embryogenesis of the loach. A possible existence is discussed of the previously unknown pathway of DNA repair with participation of DNA polymerase delta as independent from the nuclear antigen of proliferating cells.

Animals↗
PubMed2002

[Genetic diversity analysis of mitochondrial D-loop region of Chinese sucker (Myxocyprinus asiaticus)].

Chinese sucker, Myxocyprinus asiaticus, is an endemic species of China and also the only representatives of family Catostomidae in Asia. The fish was naturally distributed in Yangtze River and Mingjiang River and now few could be captured because of pollution and overexploitation. The fish has been listed in the second class of preserved animal in China. Studying and assessing its population structure is an imperative and fundamental work for making effective protection strategies. We amplified and sequenced the D-loop region of mtDNA of 8 samples. The size of the D-loop region is about 958 bp. A total of 32 variation loci were detected and the mutation rate was 0.033. All the mutation came from nucleotide substitution except one nucleotide deletion. Most of the nucleotide variations were found between the 55-365 bp region. The individual mutation rate varied from 0-1.36%, which exhibited nucleotide polymorphism to some extent among 8 samples. Compared with RAPD and other PCR-based methods, the directily sequencing of mtDNA D-loop region revealed much more genetic diversity. Meanwhile, the D-loop region of Moxostoma robustum derived from GenBank was aligned with that of Chinese sucker through CLUSTAL software. By comparison, we found that the mutation rate (0.033) of D-loop of Chinese sucker is higher than that of Moxostoma robustum (0.016).

Animals↗
PubMed2003

[The formation process of chromatoid body in spermatogenic cell of teleost, Spinibarbus caldwelli (Nichols)].

The formation process of chromatoid body in spermatogenic cell of teleost, Spinibarbus caldwelli (Nichols) was observed with electron microscopy. The chromatoid body was formed in the primary spermatogonium. First, the precursor of chromatoid body adhered to the inner surface of the nuclear envelope. The nuclear envelope where the chromatoid body adhering was destroyed. At the inner side of the precursor of chromatoid body, new nuclear envelope formed. It separated the precursor of chromatoid body from nucleus. The newly formed nuclear envelope was concaved. Thus a hollow appears on the surface of the nucleus. The precursor of chromatoid body gathered in the hollow and condensed into chromatoid body. There were many big gaps on the newly formed nuclear envelope. A little precursor of chromatoid body which had not been separated from the nucleus before comed out of the nucleus through these gaps and into the hollow, where it integrated with the chromatoid body. The way of chromatoid body formation in spermatogenic cell of Spinibarbus caldwelli was different from the way by which nuclear material comes out of the nucleus. It was suggested that there was a different way by which nuclear material could go out of the nucleus. The chromatoid body combined with mitochondria soon after it was formed, and left the hollow. During the development of the spermatogonium, the chromatoid body separated from mitochondria.

Animals↗
PubMed1992

Cyclic changes of membrane conductivity in fertilized and activated eggs of teleost (Misgurnus fossilis) and their relation to the cell shape.

Oscillations of membrane ionic conductivity, with a period similar to cell cycle duration, were observed in fertilized and activated loach (Misgurnus fossilis) eggs. In cleaving eggs the decrease in conductivity coincided with mitosis. Synchronously with the oscillations of membrane conductivity in activated as well as in fertilized eggs, rhythmic changes in blastodisc shape occurred. The blastodisc rounded up during the period of increasing membrane conductivity and flattened while conductivity decreased. Scanning microscopy of fertilized and activated eggs revealed differences in the surface relief of rounded and flattened blastodiscs.

Animals↗
PubMed1992

Mitochondrial DNA content and mitochondrial gene transcriptional activities in the early development of loach and goldfish.

The mitochondrial DNA (mtDNA) content of the mature eggs and embryos of loach and goldfish at early developmental stages were detected by means of dot hybridization. The transcription of mitochondrial cytochrome oxidase subunit I and II (COI and COII) genes during their early development was also detected by Northern hybridization. The experimental results showed that the mtDNA content of the mature egg as well as that of the embryos during the period from fertilized egg up to hatching stage in both fishes is maintained at a constant level, giving an average value of 7.40 x 107 molecules or 1.33 ng for every embryo in loach and an average value of 1.87 x 10(8) molecules or 3.31 ng for every embryo in goldfish. In both fish embryos, the COI and COII transcripts declined gradually after fertilization until late-blastula stage and then increased in early gastrula stage. This indicated that the transcription of mitochondrial genomes of these two freshwater fishes, which belong to different families, might be activated at the beginning of gastrulation. The steady-state amounts of mitochondrial messenger transcripts existing in the embryos during the early development in both fishes seemed to be regulated by both their half-lives and the transcriptional level of the mitochondrial genomes. The results showed that the transcription of the mitochondrial genome in the early developmental process in loach and goldfish was not regulated by a gene dosage mechanism.

Animals↗