Changes in Electrophoretic Patterns of Oocyte Proteins during Oocyte Maturation in Oryzias latipes

Changes in the two-dimensional SDS-electrophoretic patterns of extracts of maturing denuded oocytes of the medaka ( Oryzias latipes ) were surveyed. In oocytes without follicular constituents several proteins became detectable in the area between the acidic and slightly basic proteins on the two-dimensional electrophoretograms, while a few of the protein spots disappeared during the process of oocyte maturation. The former proteins were detected also in oocytes that were induced to mature in vivo without breakdown of the germinal vesicle. Several proteins newly observed in extracts of post-vitellogenic oocytes during maturation after breakdown of the germinal vesicle were also identified by two-dimensional electrophoresis. Of several proteins that exhibited noticeable changes in maturing oocytes, only one spot incorporated ¹⁴C-labeled amino acid during maturation, suggesting that post-translational modification of many proteins occurred during oocyte maturation.     

A possible new mechanism of temperature dependence of electron transfer in photosynthetic systems

A new theory for the electron transfer by the non-adiabatic process is formulated taking into account the origin shift and the frequency change of the vibration. The resultant formulas are quite similar to those of Jortner (Jortner, J. (1976) J. Chem. Phys. 64, 4860–4867) except that the free energy gap ΔG is used instead of the energy gap ΔE. By applying this theory to the photosynthetic electron transfer, the role of the remarkable temperature dependence of the electron transfer from cytochrome to P⁺ in Chromatium vinosum and the experimental data were reproduced very well using a small value of the coupling strength in contrast with the previous theory. This implies that proteins play a role to exclude many of the solvent molecules from the region of the electron transfer reaction between the donor and acceptor molecules. The negative activation process in the back electron transfer from Q^?_A to P⁺, the very slow back electron transfer from I^? to P⁺ and the solvent isotope effect on the cytochrome oxidation are also successfully explained by this new theory. It is shown that even a qualitative conclusion as to the molecular parameters obtained from the temperature dependence of the electron transfer is different between the present theory and that of Jortner.     

Different repeat lengths in rat satellite I DNA containing chromatin and bulk chromatin.

The nucleosome repeat structure of a rat liver chromatin component containing the satellite I DNA (repeat length 370 bp) was investigated. Digestion experiments with micrococcal nuclease, DNAase II, and the Ca2+/Mg2+-dependent endogenous nuclease of rat liver nuclei revealed a repeat unit of 185 nucleotide pairs which is shorter by approximately 10 bp than the repeat unit of the bulk chromatin of this cell type. The difference seems not to be related to the histone composition which was found to be similar in the two types of chromatin.     

Establishment of Autoantibody-Producing Cell Lines from Peripheral Blood Lymphocytes of Patients with Systemic Lupus Erythematosus

Autoantibody-producing B cell lines were established from peripheral blood lymphocytes of patients with systemic lupus erythematosus. Peripheral blood lymphocytes obtained from five of seven patients were successfully transformed by Epstein-Barr virus. Two of four established B lymphoblastoid cell lines examined in this study produced anti-nuclear factor antibodies and one of them produced anti-single-stranded DNA and anti-double-stranded DNA antibodies. These results indicate that B cell clones committed to self antigens are transformed by Epstein-Barr virus and continue to produce autoantibodies. In order to establish a monoclonal autoantibody-producing B cell line, the cells were cloned by a limiting dilution method. The data suggest that it is possible to establish a monoclonal autoantibody-producing B cell line by the combination of transformation of B cells by Epstein-Barr virus and extensive cloning.     

Contribution of microsomal cytochrome b5 electron transport system coupled with Δ5-3β-hydroxysteroid dehydrogenase to androgen synthesis from progesterone

Cytochromes P-450 and $\text{b}$₅ were observed in the microsomal fraction of interstitial tissue of rat testes. Microsomal cytochrome $\text{b}$₅ was reduced by the NADH coupled with the activities of Δ⁵-3β-hydroxysteroid dehydrogenase with Δ⁵-Δ⁴ isomerase through conversion of pregnenolone to progesterone. Activities of NADPH-supported 17α-hydroxylase and C-17-C-20 lyase which converted progesterone to androstenedione were stimulated by either the presence of NADH or the oxidative reaction by the dehydrogenase upon Δ⁵-3β-hydroxysteroids. Androstenedione production enhanced by the reaction of the dehydrogenase was decreased by addition of the antibody against NADH-cytochrome $\text{b}$₅ reductase which was purified from rat hepatic microsomes, suggesting the active participation of cytochrome $\text{b}$₅ in the androgen synthesis.     

Effect of glucose on protein phosphorylation in rat pancreatic islets

Isolated rat pancreatic islets, incubated in the presence of extracellular ³²Pi to steady state ³²P incorporation into cellular phosphopeptides, were exposed to glucose for 10 min. Glucose (16.7 mM) significantly stimulated the phosphorylation of six phosphoproteins with molecular weights of 15,000, 35,000, 49,000, 64,000, 93,000 and 138,000. Mannoheptulose (16.7 mM) markedly inhibited glucose-stimulated phosphorylation of these six phosphoproteins. This protein phosphorylation might be important in mediating glucose-stimulated insulin release.     

Fertilizability of cryopreserved zona-free hamster ova

Mature unfertilized ova from superovulated hamsters were freed from all investments and frozen at ?50°C. They were cooled at about 1°C/min to 0°C then at 0.8° to 0.6°C/min to ?50°C. At 0°C, dimethyl sulfoxide was added to a final concentration of 1.25 M. The ova were stored at ?50°C for up to four months. Thawing was performed at 2–4°C/min and followed by several washes with insemination medium. Approximately 90% of the ova were normal in appearance after thawing. The frozen and thawed ova with normal appearance could be penetrated by hamster or human spermatozoa at a rate comparable to unfrozen controls. The ability of hamster ova to tolerate storage at a relatively convenient temperature (?50°C) for long periods (tested for up to four months) makes possible their shipment at low cost to institutions lacking this resource. There they can be used for basic biological studies of sperm–egg interaction or in the clinical assessment of human sperm quality.     

Enzymatic synthesis of poly-β-hydroxybutyrate inZoogloea ramigera

The enzyme activity synthesizing poly--hydroxybutyrate (PHB) was mainly localized in the PHB-containing particulate fraction ofZoogloea ramigera I-16-M, when it grew flocculatedly in a medium supplemented with glucose. On the other hand, the enzyme activity remained in the soluble fraction, when the bacterium grew dispersedly in a glucose-starved medium.The soluble PHB synthase activity became associated with the particulate fraction as PHB synthesis was initiated on the addition of glucose to the dispersed culture. Conversely, the enzyme activity was released from the PHB-containing granules to the soluble fraction when the flocculated culture was kept incubated without supplementing the medium with glucose.PHB synthase was also incorporated into the newly formed PHB fraction when partially purified soluble PHB synthase was incubated withd(-)--hydroxybutyryl CoA in vitro.Although attempts to solubilize the particulate enzyme were unsuccessful, and the soluble enzyme became extremely unstable in advanced stages of purification, both PHB synthases had the same strict substrate specificity ford(-)--hydroxybutyryl CoA, and showed the same pH optimum at 7.0.Non-Standard Abbreviations PHB poly--hydroxybutyrate     

Nucleic acid metabolism in cold-treated wheat embryos

The incorporation of ₃₂P into nucleic acid fractions separatedon a MAK column was compared for normally germinated and cold-treatedwheat embryos. ₃₂P accumulation in DNA fraction was decreasedby cold treatment, although that in the RNA fractions was slightlypromoted. The synthesis of the fraction, probably mRNA, elutedafter the peak of heavy rRNA was enhanced in cold-treated embryosand suppressed when the embryos were cold-treated in the presenceof 8-azaguanine, an inhibitor of vernalization. (Received May 2, 1975; )     

Fatty acid and sterol compositions in mushrooms of ten species of polyporaceae

The simple lipids present in ten species of Polyporaceae (Piptororus betulinus, Coriolus pargamenus, C. versicolor, C. heteromorphus, Formitopsis cytisina, F. pinicola, Microporus flabelliformis, Gloephyllum saepiarium, Crytoderma citrinum and Grifola frondosa) were investigated. The fatty acids that these species had in common were C₁₆-saturated acids (except in P. betulinus) and C₁₈-unsaturated acids. Ergosterol and ergosta-7,22-dien-3β-ol were isolated from these mushrooms. Lupeol was obtained from G. saepiarium. Ergost-7-en-3β-ol, lanosterol and 24-methylene-24,25-dihydrolanosterol were tentatively identified.