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At least 73 records · Page 4Linked to original sources
PubMed1989

The protamine gene chromatin in developing trout testis exists in an altered state.

Micrococcal nuclease was used to probe the nucleosomal organization of the rainbow trout germ-line-specific protamine multi-gene family in testis and erythrocytes. In erythrocyte chromatin, the repressed protamine genes show a distinct nucleosomal repeat pattern. However, in early-stage testis chromatin, where the protamine genes are expressed, they lack a distinct nucleosomal repeat pattern, indicating that the disrupted chromatin structure is related to their transcriptional activity. Micrococcal nuclease-digested testis and erythrocyte chromatin was separated into soluble and insoluble fractions. Transcriptionally active/competent genes of testis that had been labeled by nuclear nick-translation were enriched in the low-salt eluted, micrococcal nuclease-sensitive chromatin fraction. This fraction was not enriched in protamine DNA sequences. In testis, but not erythrocytes, protamine DNA sequences were slightly enriched in chromatin that fractionated with insoluble nuclear material, suggesting that transcriptionally active protamine gene chromatin has an insoluble character. Since the different protamine genes may not be simultaneously expressed, our results show the distribution of both transcriptionally active and inactive protamine genes. However, our observations indicate that the active germ-line-specific protamine gene chromatin shares several, but not all, of the features associated with other active tissue-specific genes.

Animals↗
PubMed1986

Evaluation of localization and intensity of the reactions of succinic dehydrogenase, NADH tetrazole reductase and lactate dehydrogenase in developing rat testis. I. Physiological conditions.

The localization, intensity, and character of the enzymatic reactions of the following enzymes responsible for the oxygenic and nonoxygenic respiration were under examination: succinic dehydrogenase (SDH), NADH tetrazole reductase (NADH-R), and lactate dehydrogenase (LDH). The features of the enzymatic reactions enumerated above were tested in male gonads of the rats on their 1st, 4th, 7th, 15th, 30th, 45th, 60th, 90th d and 1.5 year of post-fetal life. It was estimated on the examined reactions that their metabolic maturity in the gonad was reached on the 45th d of the rat's life.

Aging↗
PubMed1986

Evaluation of localization and intensity of the reactions of succinic dehydrogenase, NADH tetrazole reductase, and lactate dehydrogenase in developing rat testis. II: After cadmium chloride treatment.

The described experiments showed the influence of a single dose of cadmium chloride (1.5 mg CdCl2/kg body mass) applied intraperitoneally on the activity of succinic dehydrogenase (SDH), NADH tetrazole reductase (NADH-R), and lactate dehydrogenase (LDH) in the rat's male gonad. It was ascertained that disturbances of the reaction begin to occur in the 7th d of post-fetal life: they increase gradually, first at the circumference and then the centre of the organ reaching their maximum in 1.5 year old rats.

Animals↗
PubMed1986

Evolution of localization of the reactions of adenosine triphosphatase (Mg++-ATP-ase), 5'nucleotidase (5'nt), alkaline phosphatase (AP), and acid phosphatase (AcP) in developing rat testis. I. Physiological conditions.

The experiments were performed upon the rats aged 1, 4, 7, 15, 30, 45, 60, 90 d, and 1,5 a. The behavior of the following reactions was described: for adenosine triphosphatase stimulated by Mg++(Mg++-ATP-ase), for 5'nucleotidase (5'Nt), for alkaline phosphatase (AP), for acid phosphatase (AcP). The first 3 are markers of the transport enzymes in cells, and the 4th is a marker of lytic processes. It was estimated on the basis of the examined reactions that a full metabolic maturity of the gonad was revealed since the 45th d of post-fetal life.

5'-Nucleotidase↗
PubMed1986

Dolichol kinase activity in the developing rat testis.

Dolichyl phosphate concentrations, a primary factor in regulating the rate of N-glycosidically linked glycoprotein synthesis, are dependent upon a cytidine triphosphate (CTP)-dependent dolichol kinase. This study examines dolichol kinase in rat testicular microsomes and defines assay conditions. As with dolichol kinases from other tissues, addition of 2-mercaptoethanol increased activity 60%. Inclusion of NaF, an inhibitor of testicular dolichyl phosphate phosphatase activity, also resulted in a 38% increase in activity. Triton X-100 was necessary for phosphorylation of both endogenous and exogenous dolichol; however, concentrations of detergent in excess of 0.25-0.35% were inhibitory. A 2- to 5-fold stimulation of kinase activity was obtained by addition of 50-100 microM exogenous dolichol. The high level of nucleoside triphosphatase activity in testicular microsomes mandated the inclusion of high levels of uridine triphosphate (UTP) to protect the [gamma-32 P] CTP. Increasing UTP concentrations up to 50 mM resulted in increased product formation. A clear requirement for divalent cations was observed; 5 mM ethylenediaminetetraacetate (EDTA) abolished activity. The following order of cation effectiveness was observed: Mn greater than or equal to Ca greater than Cd greater than Zn much greater than Mg. Ten mM optima were established for Ca2+ and Mn2+; the presence of UTP, however, results in significantly reduced concentrations of free Ca2+. Ion combination studies demonstrated interactive inhibitory effects between Ca2+ and other stimulatory divalent cations. Addition of 2 microM brain calmodulin, in the presence of 10 mM Ca2+, resulted in a 75-100% stimulation of activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1982

RNA synthesis and poly(adenosine diphosphoribosyl) synthetase activity in developing mouse testis.

RNA polymerase I and II and poly(ADP-ribosyl) synthetase activities were determined in isolated nuclei prepared from mouse testes at 1, 3, and 8 weeks after birth. RNA polymerase II and poly(ADP-ribosyl) synthetase activities increased with progression of spermatogenesis and age while RNA polymerase I activity decreased. The observed inverse relationship of RNA polymerase I and II parallels the shift in species of RNA, produced during spermatogenesis. Poly(ADP-ribosyl) synthetase activity increased with age, reaching a peak at 8 weeks. These enzymatic activities in aged mouse testis nuclei were equivalent to that of 8-week-old mice. Germ cells from the adult testis were separated by unit gravity velocity sedimentation. The enriched fractions containing pachytene and round spermatids possessed RNA polymerase and poly(ADP-ribosyl) synthetase activities. The present results suggest that transcriptional events during spermatogenesis may be modulated by changes in the activities of variants of RNA polymerase.

Animals↗
PubMed1975

Properties of chromatin subunits from developing trout testis.

When a sample of trout testis nuclei is digested with micrococcal nuclease, the DNA is cleaved almost entirely to discrete fragments approximately 200 base pairs long and multiples thereof. The same DNA fragments can be obtained when isolated chromatin, as opposed to intact nuclei, is nuclease digested. These DNA fragments can also be found in discrete chromatin "subunits" isolated from nuclease-digested nuclei. Sedimentation through sucrose gradients or velocity sedimentation in an analytical ultracentrifuge separates these chromatin subunits into 11 S (monomer), 16 S (dimer), and 22 S (trimer) etc. species. Subunits can also be fractionated on a Sepharose 2B column equilibrated and run in low salt. High salt (greater than 40 mM NaCl) or divalent cations (congruent to 5 mM) cause subunit precipitation. Chromatin subunits have a protein to DNA ratio of approximately 1.2 and contain all the histones, including the trout-specific histone T. There are, however, no detectable nonhistone chromosomal proteins. Mg-2+ precipitates of the 11 S chromatin monomers, when pelleted, are thin and clear, while oligomer Mg-2+ pellets are thick and white. This could reflect a more symmetrical or ordered packing of 11 S monomers, which are deficient in histone I. This histone may cross-link the larger oligomers, resulting in a disordered Mg-2+ complex. These results are consistent with the subunit model of chromatin structure, based on 200 base pair long regions of DNA associated with histones. These subunits would be separated by nuclease-sensitive DNA spacer regions and cross-linked by histone I.

Animals↗
PubMed1975

Sites of in vivo histone methylation in developing trout testis.

Specific lysyl residues of trout testis histones H3 and H4 are methylated partially during rainbow trout spermatogenesis. Histones H1, H2A, H2B, and protamine are not methylated. The single site (lysine 20) in histone H4 and the two major sites (lysines 9 and 27) in histone H3 are homologous to those determined for other organisms, but an additional minor site (lysine 4) occurs in histone H3. As described for calf thymus, both histones H3 and H4 contain epsilon-N-mono- and dimethyllysine, while histone H3 contains in addition, epsilon-N-trimethyllysine. The trout-specific histone H6, which accounts for 0.5 to 1.0% of total histone, contains a sequence for residues 3 to 5,-Arg-Lys-Ser-, which is the same as one methylated in histones H3, at lysines 9 and 27. However, histone H6 yields only trace amounts of [3H]methyl incorporation and no detectable methyllysines on amino acid analysis.

Alanine↗
PubMed1980

Effect of combined gonadotropin-thyrotropin treatment on development of testis and ovarium in the chickling.

Both TSH and gonadotropins stimulate the gonads in the perinatal period. Gonadotropins influence primarily the parenchyma and they induce an increase in the diameter of seminiferous tubules, and of the thickness of the ovarian cortex. TSH acts primarily on the interstice, but it acts also on the parenchyma and this action is more pronounced in the testis than in the ovary. The hormones can replace each other, and gonadotropins enhance the effect of TSH on the interstice.

Animals↗