Morphine induced thyroxine release from rat thyroid gland in vitro

Male rat thyroid glands were incubated for two hours in Krebs-Ringer bicarbonate buffer with different amounts of morphine and/or naloxone. Five micrograms/ml morphine produced a significant increase in the T4 concentration of incubation medium, and resulted in an accumulation of cAMP in the tissue. Naloxone did not change the T4 release but its incubation with morphine prevented the morphine-induced changes. Similarly, naloxone inhibited the morphine-induced accumulation of cAMP in the thyroid tissue.     

Influence of amphetamine-induced changes in the behavior of adult "aunts" on development and long term behavioral patterns of rats

Infant rats of the Wistar strain were kept either with their mother or with both the mother and the "aunt"--an adult virgin female during the suckling period. One group of aunts was injected regularly with amphetamine in the dose of 3 mg/kg b.w. (the AA group), another group with saline (the SA group). Control (CO) pups were reared by their mother only. Both acute and long term consequences of aunt-rearing on behavioral development and growth rate were observed. On Days 25 and 28 the SA pups displayed an increased exploratory activity level and more contacts with the litter-mate in the test of paired interactions when compared with both the AA and CO groups. The lowest frequency of exploratory, of manipulatory and social activities were recorded for the AA pups. In adulthood, both the aunt-reared groups of male rats exhibited higher activity level in a novel environment than the CO males. However, while in the CO and the SA males the activity level tended to habituate over the repeated tests, in the AA it persisted on a high level. The difference among females was not significant. Growth rate was retarded in the AA male and female rats.     

绿尾虹雉生态学研究

绿尾虹雉Lophophorus lhuysti生态和生物学研究是中国科学院重点科研课题——“中国珍稀濒危难类生态生物学”——部分工作。 本文为作者对绿尾虹雉所作的生态和生物学系统研究首次报道。绿尾虹雉主要牺息于海拔3,500—4,000米亚高山灌丛和草甸。杂食性鸟类,以植物性食物为主,亦食昆虫。营巢于岩洞或灌丛地面上,每窝产3—4,多达11枚卵。种群密度1.32—1.58只/km~2。目前数量急剧下降,处于濒危,急待保护。     

Host-Symbiont Specificity Expressed during Early Adsorption of Rhizobium meliloti to the Root Surface of Alfalfa

Early (4 h) adsorption of Rhizobium meliloti L5-30 in low numbers to alfalfa roots in mineral solution was examined for competition with other bacterial strains. All tested competitor strains decreased the adsorption of L5-30 by extents which depended on the strain and its concentration. The decrease of adsorption by R. meliloti competitors (all of them infective in alfalfa) was nearly complete at saturation (97 to 99% decrease). All other heterologous rhizobia and Agrobacterium tumefaciens at saturating concentrations (10⁶ to 10⁷ per ml) decreased adsorption of L5-30 only partially, less than 60%. The differential effects of homologous and heterologous competitors indicate that initial adsorption of R. meliloti to the root surface of its host occurs in symbiont-specific as well as nonspecific modes and suggest the existence of binding sites on roots which are highly selective for the specific microsymbiont in the presence of other heterologous bacteria even in very unfavorable (less than 10⁻⁴) symbiont-competitor concentration ratios.     

Glutamicin CBII,a bacteriocin-like substance produced by

Corynebacterium glutamicum CBII, in the stationary phase of growth, was found to produce spontaneously a substance resembling bacteriocins by its bactericidal properties. This substance designated glutamicin CBII was observed to exhibit bactericidal activity against coryneform bacteria (12 species tested) but not against unrelated gram-positive (3) and gram-negative (3) bacteria, while its action on bacteria with no quite known relatedness to the coryneform group (14) was found to be variable. Glutamicin CBII was partially purified by precipitation with ammonium sulphate (70% saturation), selective heat precipitation and gel chromatography on Sepadex G-50. The antibacterial substance diffused through cellophane membrane with an approximate cut-off of 10000 dalton and its sedimentation coefficient was determined to be 1.1. S by ultracentrifugation. Heating at 100°C for 30 min had no effect on its activity. Glutamicin CBII was proved to be resistant to chloroform, trypsin, chymotrypsin, pronase, and subtilisin. According to its staining behaviour and ¹H NMR spectra it probably represents a glycoprotein containing only a minor protein component.

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Protein kinase C from small intestine epithelial cells

Protein kinase C activity has been identified in cytosolic and membrane fractions from rat and rabbit small intestine epithelial cells. The cytosolic fraction comprised about the 75% of total activity. Protein kinase C activity was resolved from other protein kinase activities by ion exchange chromatography. Phosphatidylserine or phosphatidylinositol were required for protein kinase C to be active. In addition, the activity was enhanced by the presence of a diacylglycerol. Diolein and dimyristin were the most effective (13-14 fold activation). In the presence of phosphatidylserine and diolein, the Ka for activation by Ca2+ was 10(-7)M. The phorbol ester TPA substituted for diacylglycerol in activating protein kinase C. Brush border and basolateral membranes contained protein kinase C activity, although the specific activity of the basal lateral membranes was four-fold higher than the specific activity of the brush border membranes. The presence of PKC in small intestine epithelial cells might have important implications in the Ca2+ mediated control of ionic transport in this tissue.     

Pigment patterns in mutants affecting the biosynthesis of pteridines and xanthommatin in Drosophila melanogaster

Eye-color mutants of Drosophila melanogaster have been analyzed for their pigment content and related metabolites. Xanthommatin and dihydroxanthommatin (pigments causing brown eye color) were measured after selective extraction in acidified butanol. Pteridines (pigments causing red eye color) were quantitated after separation of 28 spots by thin-layer chromatography, most of which are pteridines and a few of which are fluorescent metabolites from the xanthommatin pathway. Pigment patterns have been studied in 45 loci. The pteridine pathway ramifies into two double branches giving rise to isoxanthopterin, drosopterins, and biopterin as final products. The regulatory relationship among the branches and the metabolic blockage of the mutants are discussed. The Hn locus is proposed to regulate pteridine synthesis in a step between pyruvoyltetrahydropterin and dihydropterin. The results also indicate that the synthesis and accumulation of xanthommatin in the eyes might be related to the synthesis of pteridines.Support for this work was provided to J.F. in part by a grant from the Ministerio de Universidades e Investigación (Spain) and to F.J.S. by a grant from the Ministerio de Educación y Ciencia (Spain).     

Glycogen and trehalose accumulation during colony development in Streptomyces antibioticus

Streptomyces antibioticus accumulated glycogen and trehalose in a characteristic way during growth on solid medium. Glycogen storage in the substrate mycelium took place during development of the aerial mycelium. The concentration of nitrogen source in the culture medium influenced the time at which accumulation started as well as the maximum levels of polysaccharide stored. Degradation of these glycogen reserves was observed near the beginning of sporulation. The onset of sporogenesis was always accompanied by a new accumulation of glycogen in sporulating hyphae. During spore maturation the accumulated polysaccharide was degraded. No glycogen was observed in aerial non-sporulating hyphae or in mature spores. Trehalose was detected during all phases of colony development. A preferential accumulation was found in aerial hyphae and spores, where it reached levels up to 12% of the cell dry weight. The possible roles of both carbohydrates in the developmental cycle of Streptomyces are discussed.     

The use of gold-substituted silver-intensified diaminobenzidine (DAB) and non-intensified DAB for simultaneous electron microscopic immunoperoxidase labeling of tyrosine hydroxylase and glutamic acid decarboxylase immunoreactivity in the rat medial preoptic area

An improved gold-substituted silver intensification procedure for the peroxidase-diaminobenzidine (DAB) reaction product was developed. The method was applied in the rat medial preoptic area to label tyrosine hydroxylase (TH)-immunoreactive profiles. Following the gold toning, the same sections were immunostained for glutamic acid decarboxylase (GAD) immunoreactivity with non-intensified peroxidase-DAB. Single DAB-labeled GAD axons were found in symmetric synaptic connection with unlabeled dendrites as well as with gold-toned immunoperoxidase-containing TH neurons.