Triterpenoidal saponins from Dumasia Truncata

Extraction of the aerial parts of Dumasia truncata Sieb et Zucc. afforded two new triterpenoidal saponins, together with four known ones. The structures of the new compounds were elucidated by spectral analysis as 3-O--l-rhamnopyranosyl-(1 → 3)-β-d-glucuronopyranosy-28-O-β-d-glucopyransoyl hederagenin and 3-O-β-d-xylopyranosyl-(1 → 2)-[-l-rhamnopyranosyl(1 → 3)]-β-d-glucuronopyranosyl oleanic acid.     

Changes in chorion proteins induced by the exudate released from the egg cortex at the time of fertilization in the teleost, Oryzias latipes

The chorion of unfertilized medaka Oryzias latipes eggs consists of two major proteins (77–73 and 49 kDa) and a minor 150 kDa protein. Upon fertilization, these major chorion proteins are polymerized to insoluble high molecular weight proteins via the temporary formation of several new proteins (132, 114, 62 and 61 kDa). Increasing chorion toughness is closely related to the formation of high molecular weight proteins and the increasing insolubility of the chorion proteins. The changes in chorion proteins and hardening could be induced in vitro in isolated chorions by an egg exudate, which includes cortical alveolar contents. The effects of temperature and pH on the egg exudate-induced changes in chorion proteins were examined in the present study. The major proteins could be digested by proteolytic enzymes. The 49 kDa protein was PAS-positive. Analysis with polyclonal antibodies against the major proteins demonstrated that the temporarily formed 62 and 61 kDa proteins were derived from the 77–73 kDa protein and that higher molecular weight proteins, newly formed in the process of chorion hardening, contained the same epitopes as did the 77–73 and 49 kDa proteins. The results suggest that the changes in chorion proteins of the medaka egg at the time of fertilization can be induced by an enzyme(s) released from the egg cortex into the perivitelline space.     

Changes in spatial distribution during the life history of a tropical tree,Scaphium macropodum (Sterculiaceae) in borneo

We studied the spatial distribution of fruits and plants, mortality and growth rates ofScaphium macropodum (Sterculiaceae) in four 1-ha plots in a tropical rain forest in West Kalimantan, Indonesia. The species is a large deciduous tree and produces wind-dispersed fruits on defoliated twigs. The density of dispersed fruits on the ground decreased with increasing distance from a parent tree. The area under the parent's crown had the highest density of the fruits and the highest mortality of the seedlings immediately after germination. Consequently, the density of the established seedlings peaked 14 m from the tree which is outside its crown. Thick litter mainly from the parent tree seemed to physically prevent the seedlings' root from reaching the soil surface and caused the high mortality. Juvenile and mature trees distributed exclusively, suggesting that regeneration is the most successful outside of the crown of mature trees. Saplings under canopy shade did not grow well.Scaphium macropodum is hypothesized to require a gap for seedling growth and successful regeneration, whereas it can germinate and last under closed canopies as suppressed seedlings or saplings.     

RAD51 homologues in Xenopus laevis: two distinct genes are highly expressed in ovary and testis

The RAD51 gene is a eukaryotic counterpart of the Escherichia coli recA gene which is involved in genetic recombination. Two distinct Xenopus laevis RAD51 cDNA clones (XRAD51.1 and XRAD51.2) were isolated from an oocyte cDNA library using the human RAD51 cDNA (HsRAD51) as a probe. Sequence analysis revealed that 98.2% of the amino-acid residues were identical between XRAD51.1 and XRAD51.2, and that both were 95% identical to HsRAD51. Both of the XRAD51 genes were expressed at a higher level in ovary and testis than in other somatic tissues, suggesting their involvement in meiotic recombination. The expression of XRAD51.1 was about eightfold in excess of that of XRAD51.2 in all of the tissues examined. Analysis of the rates of synonymous substitution in the coding sequences of the two XRAD51 suggests that these two genes diverged about 50 million years ago. The structural similarities of the XRAD51 proteins to RecA in E. coli and Rad51 in yeasts or vertebrates are discussed.     

An immunological study of delta-aminolevulinic acid dehydratase specificity consistent with the phylogeny of species

Rabbit antibody directed to homogeneously purified mouse liver delta-aminolevulinic acid dehydratase cross-reacted with the enzyme in erythrocytes, spleen, kidney and brain in the mouse. The antibody also cross-reacted with the enzyme in the rat, hamster and gerbil, but not in the rabbit, guinea pig, cattle, chick embryo, and human. In contrast, rabbit antibody against the human enzyme partially recognized the monkey enzyme, but not the enzyme in the other species. The species specificity of delta-aminolevulinic acid dehydratase in this study was consistent with the phylogenetic evolution of the species examined.     

Fluorometric measurement of tin-protoporphyrin in biological samples

Sn-protoporphyrin is a potent competitive inhibitor of heme oxygenase, can suppress neonatal and other forms of hyperbilirubinemia in laboratory animals, and represents a potential new approach to the treatment of neonatal jaundice in humans. In order to study the disposition of Sn-protoporphyrin in vivo we have developed a sensitive fluorometric method for the quantitation of this metalloporphyrin in biological samples. The method is sensitive to concentrations as low as 0.01 nmol/ml, and is specific for Sn-protoporphyrin even in the presence of other porphyrins such as protoporphyrin.     

Assignment of the gene for uroporphyrinogen decarboxylase to human chromosome 1 by somatic cell hybridization and specific enzyme immunoassay

Summary A specific enzyme immunoassay of uroporphyrinogen decarboxylase was developed and applied to the detection of the human enzyme in man-rodent somatic cell hybrids. This method allowed to assign the gene for uroporphyrinogen decarboxylase to human chromosome 1.     

Metabolism of Tritiated Gibberellin A(20) in Immature Seeds of Dwarf Pea, cv. Meteor

Tritium-labeled gibberellin A₂₀ ([³H]GA₂₀) was applied via the pedicel to immature pods and seeds of dwarf peas and three harvests were made at days 5, 10, and 23 (mature) after application. Of the five metabolites of [³H]GA₂₀, the three in highest yield were GA₂₉, an α,β-unsaturated ketone, and a compound (B), whose structure was only tentatively assigned. The metabolic sequence GA₂₀ → GA₂₉ → compound B → the ketone was indicated. The amount of [³H]GA₂₉ in both seeds and pods was highest at day 5 and declined to its lowest level at maturity. The amount of the [³H]ketone in the seed increased with time to its highest level at maturity. It is suggested that compound B and the ketone represent the major pathway of catabolism of GA₂₉, a 2β-hydroxylated GA of low biological activity, and that the ketone is not metabolized, or only slowly metabolized, during seed maturation.     

Arachidonate metabolism in bovine gallbladder muscle

Incubation of [1-¹⁴C]arachidonic acid (AA) with homogenates of bovine gallbladder muscle generated a large amount of radioactive material having the chromatographic mobility of 6-keto-PGF_1α (stable product of PGI₂) and smaller amounts of products that comigrated with PGF_2α and PGE₂. Formation of these products was inhibited by the cyclooxygenase inhibitor indomethacin. The major radioactive product identified by thin-layer chromatographic mobility and by gas chromatography - mass spectrometric analysis was found to be 6-keto-PGF_1α. The quantitative metabolic pattern of [1-¹⁴C]PGH₂ was virtually identical to that of [1-¹⁴C]AA. Incubation of arachidonic acid with slices of bovine gallbladder muscle released labile anti-aggregatory material in the medium, which was inhibited by aspirin or 15-hydroperoxy-AA.These results indicate that bovine gallbladder muscle has a considerable enzymatic capacity to produce PGI₂ from arachidonic acid.     

Suppression of the development of uterine adenomyosis by danazol treatment in mice.

Inhibitory effects of danazol, an isoxazol derivative of synthetic steroid 17 alpha-ethinyl-testosterone, on the development of uterine adenomyosis, a pathological disorder of endometrial tissue defined as the presence of endometrial glands and stroma in the myometrium, were investigated in mice of SHN strain. Mice treated with 0.5 microgram danazol for 5 weeks during 4-9 weeks of age and killed at 21 weeks of age showed significantly lower incidence of the spontaneous development of adenomyosis than the age-matched intact control mice. The inhibitory effects of danazol were also evident in mice bearing pituitary isografts which were effective in inducing an early and a high incidence of adenomyosis. Furthermore, the treatment with danazol resulted in the decrease of serum levels of luteinizing hormone (LH) and prolactin (PRL) associated with hypofunction of ovaries and persistent diestrus. These results support the usefulness of danazol for the clinical treatment of gynecological disorders except for hypofunction of ovaries.