Endocrine function in a case of beta-adrenergic hyperdynamic circulatory state.

Endocrine functions were investigated in a case of "beta-adrenergic hyperdynamic circulatory state". This state was diagnosed by (1) typical symptoms of cardiac awareness, (2) physical findings (increments of pulse rate and blood pressure by changing positions or walking), (3) increase in cardiac output (5.25 l/min leads to 14.03 l/min) and decrease in circulatory time (10.8 sec leads to 5.5 sec) by isoproterenol infusion (0.02 mug/min/kg body weight), (4) rapid loss of symptoms and above findings by propranolol treatment (30 mg per os daily) and reappearance by discontinuing medication. The mechanism of insulin response to glucose has been a controversy as to whether the secretion is transmitted by beta-receptor or independent glucose receptor. And in this physiologic beta-adrenergic state, it was found that insulin responses in IVGTT and OGTT were within normal limit. When beta-adrenergic condition was corrected by propranolol treatment, insulin responses were shown lowered, though in the normal range. This could be reproduced by discontinuing medication. Insulin, glucagon and growth hormone secretions caused by arginine were also found normal, but during the period the patient was on propranolol therapy, all responses were decreased, within the normal range. These results do not positively support the idea that glucose receptor is linked to beta-receptor. They do not either agree with the contention that secretions of insulin, glucagon and growth hormone induced by arginine are mediated through beta-receptors.     

Limited proteolysis of a chemically modified third component of human complement, C3, by cathepsin G of human leukocytes

We have investigated the limited proteolysis of the third component of complement, C3, by a human leukocyte protease, cathepsin G, by using a chemically modified C3, which was prepared by treatment of C3 with methylamine and a fluorescent thiol reagent, N-(dimethylamino-4-methylcoumarinyl)-maleimide (DACM) and was thus named DACM-C3me. Although native C3 was hardly cleaved by cathepsin G, DACM-C3me was cleaved by cathepsin G into three major fragments, which were termed C3c-G (150,000 daltons, 150 kd), C3d-G (25 kd), and C3a-G (10 kd). C3c-G was composed of four disulfide-linked polypeptide chains of 75 kd, 35 kd, and two 25 kd. C3d-G and C3a-G were single-chain fragments derived from the alpha chain. The N-terminal sequence of C3d-G was determined as Thr-Glu-Asp-Ala-Val-, suggesting that cathepsin G released C3d-G by cleaving a Met-Thr peptide bond which is located at 19 residues toward the N-terminal from the cysteinyl residue forming an internal thiolester linkage in native C3. C3d-G, like C3d-K (a C3d fragment produced by the action of plasma kallikrein), was found to have bioactivities such as leukocytosis-inducing and immunosuppressive activities.     

Release of 6-keto-prostaglandin F1α and thromboxane B2 from mouse peritoneal macrophages during their adhesion and spreading on a glass surface

The release of 6-keto-prostaglandin F_1α (6KF_1α)_and of thromboxane B₂ (TXB₂) from cells were investigated using mouse peritoneal exudate cells (PECs) and non-cultured peritoneal macrophages. They were prepared by adhesion to glass dishes and incubated for 1 hr at 37°C in 5% Co₂ in air. Both the percentage of spreading macrophages and the release of 6KF_1α and TXb₂ increased in proportion to the incubation time. 6KF_1α and TXB₂ were released from the macrophages, not from the non-adherent cells. When PECs were incubated in silicon-coated glass dishes, the spreading of macrophages was hardly detected and lower amounts of 6KF_1α and TXB₂ were released from these cells compared with cells incubated in non-treated glass dishes. These findings suggest that adhesion with the correlated spreading of macrophages on glass dishes serve as a considerable physical factor for the release of 6KF_1α and TXB₂.     

Protein-Calcium-Phytic Acid Relationships in Soybean

This paper constitutes the first report in a research series undertaken in order to clarify the interactive relationships among soybean meal protein, calcium and phytic acid in solution and in precipitate.

Data presented are mainly concerned with solubility characteristics of soybean meal proteins as a function of pH. The results support the suggestion as follows; phosphorus and calcium give the remarkable effects on solubility characteristics of protein, the complex containing protein, calcium and phosphorus is formed above isoelectric point of protein and the combinations are labile above at pH 8, especially by heating.     

Two ANGUSTIFOLIA genes regulate gametophore and sporophyte development in Physcomitrella patens

In Arabidopsis thaliana the ANGUSTIFOLIA (AN) gene regulates the width of leaves by controlling the diffuse growth of leaf cells in the medio‐lateral direction. In the genome of the moss Physcomitrella patens, we found two normal ANs (PpAN1‐1 and 1‐2). Both PpAN1 genes complemented the A. thaliana an‐1 mutant phenotypes. An analysis of spatiotemporal promoter activity of each PpAN1 gene, using transgenic lines that contained each PpAN1‐promoter– uidA (GUS) gene, showed that both promoters are mainly active in the stems of haploid gametophores and in the middle to basal region of the young sporophyte that develops into the seta and foot. Analyses of the knockout lines for PpAN1‐1 and PpAN1‐2 genes suggested that these genes have partially redundant functions and regulate gametophore height by controlling diffuse cell growth in gametophore stems. In addition, the seta and foot were shorter and thicker in diploid sporophytes, suggesting that cell elongation was reduced in the longitudinal direction, whereas no defects were detected in tip‐growing protonemata. These results indicate that both PpAN1 genes in P. patens function in diffuse growth of the haploid and diploid generations but not in tip growth. To visualize microtubule distribution in gametophore cells of P. patens, transformed lines expressing P. patens α‐tubulin fused to sGFP were generated. Contrary to expectations, the orientation of microtubules in the tips of gametophores in the PpAN1‐1/1‐2 double‐knockout lines was unchanged. The relationships among diffuse cell growth, cortical microtubules and AN proteins are discussed.     

A Highlights from MBoC Selection: Serine 129 phosphorylation of membrane-associated α-synuclein modulates dopamine transporter function in a G protein–coupled receptor kinase–dependent manner

Most α-synuclein (α-syn) deposited in Lewy bodies, the pathological hallmark of Parkinson disease (PD), is phosphorylated at Ser-129. However, the physiological and pathological roles of this modification are unclear. Here we investigate the effects of Ser-129 phosphorylation on dopamine (DA) uptake in dopaminergic SH-SY5Y cells expressing α-syn. Subcellular fractionation of small interfering RNA (siRNA)–treated cells shows that G protein–coupled receptor kinase 3 (GRK3), GRK5, GRK6, and casein kinase 2 (CK2) contribute to Ser-129 phosphorylation of membrane-associated α-syn, whereas cytosolic α-syn is phosphorylated exclusively by CK2. Expression of wild-type α-syn increases DA uptake, and this effect is diminished by introducing the S129A mutation into α-syn. However, wild-type and S129A α-syn equally increase the cell surface expression of dopamine transporter (DAT) in SH-SY5Y cells and nonneuronal HEK293 cells. In addition, siRNA-mediated knockdown of GRK5 or GRK6 significantly attenuates DA uptake without altering DAT cell surface expression, whereas knockdown of CK2 has no effect on uptake. Taken together, our results demonstrate that membrane-associated α-syn enhances DA uptake capacity of DAT by GRKs-mediated Ser-129 phosphorylation, suggesting that α-syn modulates intracellular DA levels with no functional redundancy in Ser-129 phosphorylation between GRKs and CK2.     

Hepatocyte-specific distribution of catalase and its inhibitory effect on hepatic ischemia/reperfusion injury in mice

To explore the possibility of using catalase for the treatment of reactive oxygen species (ROS)-mediated injuries, the pharmacokinetics of bovine liver catalase (CAT) labeled with ¹¹¹In was investigated in mice. At a dose of 0.1 mg/kg, more than 70% of ¹¹¹In-CAT was recovered in the liver within 10 min after intravenous injection. In addition, ¹¹¹In-CAT was predominantly recovered from the parenchymal cells (PC) in the liver. Increasing the dose retarded the hepatic uptake of ¹¹¹In-CAT, suggesting saturation of the uptake process. This cell-specific uptake could not be inhibited by coadministration of various compounds which are known to be taken up by liver PC, indicating that the uptake mechanism of CAT by PC is very specific to this compound. The preventive effect of CAT on a hepatic ischemia/reperfusion injury was examined in mice by measuring the GOT and GPT levels in plasma. A bolus injection of CAT at 5 min prior to the reperfusion attenuated the increase in the levels of these indicators in a dose-dependent manner. These results suggest that catalase can be used for various hepatic injuries caused by ROS.