Streptococcus pyogenes upregulates arginine catabolism to exert its pathogenesis on the skin surface

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Isolation of glucagon-secreting cell lines by cloning insulinoma cells

Summary Six glucagon-secreting cell lines designated as In-R1G1,-G3,-G7,-G9,-G10, and-G11 were isolated from insulinoma cells (In-111-R1) by single cell cloning. A small amount of insulin was also detectable in the incubation medium when hormone secretion was stimulated by the addition of arginine or theophylline. These cell lines grew as monolayers and the population doubling times varied from 16.8 to 28.8 h. Karyologically these clones were aneuploid and the modes of chromosome numbers were 61 to 70. Electron microscopic examination of one of these clones showed that these cells contained moderately developed Golgi apparatus and a few secretory granules, which more or less resembled α-cell granules. By gell filtration study of the incubation medium, glucagon and glucagonlike material were eluted. The molecular weight of the latter was approximately 9000, which suggested the concomitant secretion of rpoglucagon into the medium. The levels of secreted glucagon in basal state were 0.3 to 3.0 ng/10⁶ cells/2 h. Glucagon secretion was markedly enhanced in the presence of amino acids. Glucagon secretion increased slightly in the presence of high concentration of glucose in Hanks' balanced salt solution; however it was not affected by the varying concentrations of glucose when the cells were incubated in complete media with amino acids. Glucagon secretion was also stimulated by the addition of theophylline. These clonal cell lines seem to provide a useful tool for investigating the mechanism of glucagon secretion.     

Radioautographic studies on the formation and maturation of bone marrow lymphocytes in mice

Abstract. DNA labelling by [³H]thymidine and the sandwich radioimmunolabelling method were used to characterize marrow lymphoid cells and to study the kinetics of production and maturation of small lymphocytes in the bone marrow of adult mice. Marrow lymphoid cells consisted of non-proliferating small lymphocytes, 30–40% of which had detectable surface immunoglobulin (SmIg), and proliferating large lymphoid cells lacking SmIg. Double-labelling experiments employing [³H]thymidine in vivo followed by sandwich radioimmunolabelling in vitro indicated that marrow small lymophocytes lack detectable SmIg when they are formed but develop SmIg within the first few days after production. Marrow lymphocytopoiesis includes; (1) praliferation of large lymphoid cells, which are presumptive small lymphocyte progenitors, which have a cell cycle time of 14–15 hr, and (2) a 3–5-day intramyeloid stage when many newly formed small lymphocytes undergo maturational changes towards the B cell lineage.     

Natural hybridization in JapaneseCalamagrostis

Taxonomic relationships betweenCalamagrostis langsdorffii andC. sachalinensis were investigated in connection with the discovery that a considerable number of plants intermediate between these species occur in the high mountains of central Honshu. The studies were mainly carried out on the basis of cytological voucher specimens for which a chromosome number was known. Their morphological features, leaf flavonoids and pollen grains were subjected to examination. Hybridization, polyploidy and gametophytic apomixis are related to the organization of this complex, and plants referable to the “intermediates” are apomictic octoploids superimposed on the ancestral and sexual tetraploid taxa. The internal structure of this complex is discussed together with its probable course of evolution, and a diagram showing the outline of the structure is presented. The variability of morphological features and flavonoid patterns of the plants concerned is examined, and the delimitation ofC. langsdorffii andC. sachalinensis is made clearer.     

Identification of 5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,25,26-hexol in human urine

A new bile alcohol, 5 beta-cholestanehexol, was identified in the urine of healthy humans as the glucuronide. The bile alcohol glucuronide fraction was isolated by an ion exchange chromatography on piperidinohydroxypropyl Sephadex LH-20. After enzymatic hydrolysis, the bile alcohols were converted into trimethylsilyl ether derivatives and analyzed by a combination of gas-liquid chromatography and mass spectrometry. The major bile alcohol was 27-nor-5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,25-pentol. As minor constituents the following C26 and C27 bile alcohols were identified: 27-nor-5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,25,26-hexol, 5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,25-pentol, 5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,26-pentol, 5 beta-cholestane-3 alpha,7 alpha,12 alpha,25,26-pentol. In addition to these bile alcohols, a new bile alcohol was identified as a sixth component of the urinary bile alcohols. The structure was assigned as (24S)-5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,25,26-hexol by the direct comparison of mass spectral data and chromatographic properties with synthetic standard. The average daily excretion of the new bile alcohol was 28.6 micrograms and 3.0% of the total bile alcohols. The presence of 27-nor-5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,25-pentol and 27-nor-5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,25,26-hexol suggests that 26-hydroxylation of 5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,25-pentol is most likely for the biosynthesis of this new bile alcohol.     

alpha-Lactalbumin: a calcium metalloprotein

Metal analyses and the studies of the effects of EDTA on unfolding reactions have shown that α-lactalbumin is a calcium metalloprotein. The role of the calcium binding in its biological activity is considered. A plausible site of binding is presented on the basis of the metal-binding site of lysozyme and of the structural models of the protein based on the lysozyme structure.     

Flavonoid glycosides from fiveCyathea species

The leaves of 5 fern species of the genusCyathea, i.e.C. fauriei, C. mertensiana, C. leichhardtiana, C. podophylla andC. hancockii, have been chemically analysed. The former 3 species have kaempferol 3-sophoroside (sophoraflavonoloside) and kaempferol 7-rhamnoglucoside as glycosidic components, and the latter 2 species contain kaempferol 3-galactoside (trifolin) and kaempferol 3-rhamnoglucoside (nicotiflorin). In addition, vitexin, orientin, kaempferol 3-glucoside (astragalin), kaempferol 3-rhamnoside (afzelin) and kaempferol 7-arabinoside are detected as common constituents in all the 5 species analysed.     

Characteristics of Bupleurum falcatum plants propagated through somatic embryogenesis of callus cultures

Various characteristics including the saponin content in the root of Bupleurum falcatum plants propagated in vitro through somatic embryogenesis of callus cultures were compared with those of the plants propagated by seeds. The asexually propagated plants had an aerial part of more uniform characteristics than those of sexually propagated ones. However, both the mean and variance of root weight of the former were significantly larger than those of the latter. As for the saponin content of the root on a dry weight basis, there was little difference between the two groups. The amounts of saikosaponins c and d in a root were significantly larger in the asexually propagated plants than in the sexually propagated ones.