Atrial and brain natriuretic peptide in adrenal steroidogenesis.

We elucidated the role of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in human and bovine adrenocortical steroidogenesis. The urinary volume, sodium excretion and cyclic GMP (cGMP) excretion and plasma cGMP were markedly increased by the synthetic alpha-human ANP (alpha-hANP) infusion in healthy volunteers. Plasma arginine vasopressin (AVP) and aldosterone levels were significantly suppressed. Both ANP and BNP inhibited aldosterone, 19-OH-androstenedione, cortisol and DHEA secretion dose-dependently and increased the accumulation of intracellular cGMP in cultured human and bovine adrenal cells. alpha-hANP significantly suppressed P450scc-mRNA in cultured bovine adrenal cells stimulated by ACTH. Autoradiography and affinity labeling of [125I]hANP, and Scatchard plot demonstrated a specific ANP receptor in bovine and human adrenal glands. Purified ANP receptor from bovine adrenal glands identified two distinct types of ANP receptors, one is biologically active, the other is silent. A specific BNP receptor was also identified on the human and bovine adrenocortical cell membranes. The binding sites were displaced by unlabelled ANP as well as BNP. BNP showed an effect possibly via a receptor which may be shared with ANP. The mean basal plasma alpha-hANP level was 25 +/- 5 pg/ml in young men. We confirmed the presence of ANP and BNP in bovine and porcine adrenal medulla. Plasma or medullary ANP or BNP may directly modulate the adrenocortical steroidogenesis. We demonstrated that the lack of inhibitory effect of alpha-hANP on cultured aldosterone-producing adenoma (APA) cells was due to the decrease of ANP-specific receptor, which caused the loss of suppression of aldosterone and an increase in intracellular cGMP.     

Regional and Temporal Alterations in Ca2+/Calmodulin-Dependent Protein Kinase II and Calcineurin in the Hippocampus of Rat Brain After Transient Forebrain Ischemia

We have investigated regional and temporal alterations in Ca2+/calmodulin-dependent protein kinase II (CaM kinase II) and calcineurin (Ca2+/calmodulin-dependent protein phosphatase) after transient forebrain ischemia. Immunoreactivity and enzyme activity of CaM kinase II decreased in regions CA1 and CA3, and in the dentate gyrus, of the hippocampus early (6-12 h) after ischemia, but the decrease in immunoreactivity gradually recovered over time, except in the CA1 region. Furthermore, the increase in Ca2+/calmodulin-independent activity was detected up to 3 days after ischemia in all regions tested, suggesting that the concentration of intracellular Ca2+ increased. In contrast to CaM kinase II, as immunohistochemistry and regional immunoblot analysis revealed, calcineurin was preserved in the CA1 region until 1.5 days and then lost with the increase in morphological degeneration of neurons. Immunoblot analysis confirmed the findings of the immunohistochemistry. These results suggest that there is a difference between CaM kinase II and calcineurin in regional and temporal loss after ischemia and that imbalance of Ca2+/calmodulin-dependent protein phosphorylation-dephosphorylation may occur.     

Intracellular free Ca2+ concentration in fowl spermatozoa and its relationship to motility and respiration in spermatozoa.

The ability of fowl spermatozoa to accumulate and de-esterify the intracellular fluorescent Ca2+ indicator fura-2 was established. The cytosolic Ca2+ concentrations, measured by this technique, did not change after the addition of 1 mmol EGTA l-1. Subsequently, addition of the calcium ionophore A23187 caused a reduction in cytosolic Ca2+ concentrations, presumably by efflux of Ca2+ from the spermatozoa. Intracellular free Ca2+ concentrations were then significantly increased by the addition of 1 mmol CaCl2 l-1. The motility of demembranated spermatozoa gradually decreased after the addition of EGTA alone or EGTA with A23187, but was instantly restored by the addition of CaCl2 in the presence of both EGTA and A23187. Unlike demembranated spermatozoa, intact spermatozoa maintained their motility, even after the addition of EGTA, but their motility was reduced by the addition of A23187 in the presence of EGTA. The addition of A23187 also reduced the rate of oxygen consumption, but not the ATP concentrations in intact spermatozoa. These results demonstrate that the motility and respiration of fowl spermatozoa are strongly influenced by their intracellular Ca2+ concentrations.     

Parturition in a free-ranging Japanese monkey (Macaca fuscata)

Parturition behavior of a multiparous female and her interactions with group members throughout the birth process were recorded for a free-ranging Japanese monkey (Macaca fuscata). The female showed evidence of 18 contractions during the 35 min prior to delivery, with a mean duration and a mean intercontraction interval of 30 sec and 96 sec, respectively. These values were similar to those in individually caged Japanese monkeys. Some adult females remained in proximity to the female who was giving birth during the prepartum phase, and her 2-year-old daughter watched the delivery of the infant. Even during the prepartum phase the female moved in order to keep up with the group which traveled from the feeding site to a sleeping site in the forest.     

Secretory expression of a glutamic-acid-specific endopeptidase (SPase) from Staphylococcus aureus ATCC12600 in Bacillus subtilis

Summary In order to obtain a large quantity of glutamic-acid-specific endopeptidase of Staphylococcus aureus ATCC12600 (SPase) without cultivating its pathogenic host bacterium, expression plasmids enabling secretion of SPase from Bacillus subtilis were constructed by inserting the SPase gene into B. subtilis-Escherichia coli shuttle vectors. B. subtilis harbouring a simple recombinant plasmid containing the coding and the 5-flanking regions of SPase in the shuttle vector pHY300PLK secreted 22 mg/l of SPase into the medium. As this level was lower than that of the natural strain (45 mg/l), we tried to increase the expression level by constructing a series of hybrid plasmids with the following features: (1) the terminator sequence of the alkaline protease gene from B. subtilis, (2) the promoter and the leader sequences of the -amylase gene or of alkaline protease gene from B. amyloliquefaciens, (3) the vector pHY300PLK and the fused vector of pHY300PLK and pUB110. By using a variety of hybrid plasmids, the resulting transformants secreted SPase at levels of 33–120 mg/l. The recombinant SPase isolated from the medium was indistinguishable from the natural one with respect to its behaviour on sodium dodecyl sulphate-polyacrylamide gel electrophoresis and Western blotting as well as its enzyme activity.Correspondence to: S. Kakudo     

Schistosoma japonicum: Immediate hypersensitivity reactions to egg antigen in humans and rodents

Immediate hypersensitivity reactions in schistosoma japonicum infections were examined in both man and experimental animals. In man higher reaction to soluble egg antigen than to adult worm antigen was detected by the use of the radioallergosorbent test (RAST). Blood-collecting filter paper can be used in RAST for seroepidemiological study in place of a skin test. Reaginic antibody formation against egg antigen was detected at the approximate time of egg deposition in strains of mice, Mongolian gerbils, cotton rats, and laboratory rats by the use of passive cutaneous anaphylaxis or Prausnitz-Küstner-type skin tests. At the same time circumoval precipitin tests were positive. Results with athymic nude mice suggest that these reactions are T-cell dependent. No detectable reagin synthesis against adult worm antigen was found in the animals so far examined, confirming stronger allergenic reaction to egg antigen than to that of adult worms in S. japonicum infections in man and animals.     

Acceleration of the Decay of Membrane Potential after Energization of Chloroplasts in Intact Zea mays Leaves

The relationship between dissipation of the flash-induced membranepotential across the thylakoid membrane and the high energystate was studied in Zea mays leaves. The dark decay of theflash-induced 515-nm absorbance change was accelerated by shortpreillumination of the leaf. No acceleration of the decay bypreillumination was observed when leaves were incubated in argonor CO² gas or treated with DCMU. These effects of preilluminationand incubation were reversible. The delayed fluorescence from chlorophyll a was reversibly decreasedby incubating leaves in argon or CO² gas, though the modes ofdepression were somewhat different from each other. In leavesincubated in argon or CO² gas, the phase of slow decrease ofthe intensity of prompt fluorescence during illumination reversiblydisappeared. The results suggested that the dissipation of membrane potentialgenerated by a flash was accelerated after the energizationof chloroplasts in leaves, probably by increased H^– permeabilityof the thylakoid membrane. O2 was important in maintaining (indarkness) and forming (under illumination) the high energy statein chloroplasts in intact leaves. (Received October 1, 1980; Accepted December 15, 1980)     

Cartilage-derived factor (CDF) : II. Somatomedin-like action on cultured chondrocytes

Previously, we showed that fetal bovine cartilage contains a polypeptide that stimulates the incorporation of [³⁵S]sulfate into proteoglycans synthesized by rat and rabbit costal chondrocytes in culture. In this paper, we report that the cartilage-derived factor (CDF) increases not only [³⁵S]sulfate incorporation but also [³H]thymidine incorporation into rabbit chondrocytes in monolayer culture. The dose-response curve of CDF stimulation of DNA synthesis was similar in profile to that of CDF stimulation of proteoglycan synthesis. In addition, CDF markedly enhanced [³H]uridine incorporation into rabbit chondrocytes and significantly enhanced [³H]serine incorporation into total protein. These findings indicate that fetal bovine cartilage contains a factor that shows somatomedin-like activity in monolayer cultures of rabbit chondrocytes.     

Selective degradation of altered tomato β-fructofuranosidase molecules by neutral protease

Evidence is presented for the selective breakdown of altered tomato β-fructofuranosidase molecules by a neutral protease from Bacillus subtilis.