Diverse Expression of β1,4-N-Acetylgalactosaminyltransferase Gene in the Adult Mouse Brain

Abstract: Among various tissues of mouse, β1,4- N -acetylgalactosaminyltransferase (GM2/GD2 synthase) gene is expressed predominantly in the brain. Further analysis of the gene expression in the mouse CNS was performed by northern blotting and by enzyme assays using extracts from various parts of the CNS. In situ hybridization was also done to investigate the distribution of cells generating GM2/GD2 synthase. In northern blots, diverse levels of the gene expression were observed, depending on the regions examined. By in situ hybridization, pyramidal cells in the hippocampus, granular cells in dentate gyrus and cerebral cortex, Purkinje cells in cerebellum, and mitral cells in the olfactory bulb expressed high levels of the mRNA; these results corresponded to the results obtained by northern blot. Enzyme levels in these sites were accordingly high. However, enzyme levels in certain areas with low mRNA intensities, such as thalamus and pons medulla, were higher than expected from the results of northern blotting. The significance of the high gene expression in certain areas for brain function and the reason for the discrepancy between mRNA level and enzyme activity in some regions are discussed.     

Control of the rate of phosphocreatine resynthesis after exercise in trained and untrained human quadriceps muscles

We examined the effect of differences in exercise intensity on the time constant (t _c) of phosphocreatine (PCr) resynthesis after exercise and the relationships betweent _c and maximal oxygen uptake (VO_2max) in endurance-trained runners (n = 5) and untrained controls (n = 7) (average VO_2max = 66.2 and 52.0 ml · min^–1 · kg^–1, respectively). To measure the metabolism of the quadriceps muscle using phosphorus nuclear magnetic resonance spectroscopy, we developed a device which allowed knee extension exercise inside a magnet. All the subjects performed four types of exercise: light, moderate, severe and exhausting. The end-exercise PCr: [PCr + inorganic phosphate (P_i)] ratio decreased significantly with the increase in the exercise intensity (P < 0.01). Although there was little difference in the end-exercise pH, adenosine diphosphate concentration ([ADP]) and the lowest intracellular pH during recovery between light and moderate exercise, significant changes were found at the two higher intensities (P < 0.01). These changes for runners were smaller than those for the controls (P < 0.05). The _c remained constant after light and moderate exercise and then lengthened in proportion to the increase in intensity (P < 0.05). The runners had a lowert _c at the same PCr and pH than the controls, particularly at the higher intensity (P < 0.05). There was a significant correlation betweent _c and [ADP] in light exercise and betweent _c and both end-exercise PCr and pH in severe and exhausting exercise (P < 0.05). The threshold of changes in pH andt _c was a PCr: (PCr + P_i) ratio of 0.5. There was a significant negative correlation between the VO_2max andt _c after all levels of exercise (P<0.05).However, in the controls a significant correlation was found in only light and moderate exercise (P < 0.05). These findings suggest the validity of the use oft _c at an end-exercise PCr:(PCr + P_i) ratio of more than 0.5 as a stable index of muscle oxidative capacity and the correlation between local and general aerobic capacity. Moreover, endurance-trained runners are characterized by the faster PCr resynthesis at the same PCr and intracellular pH.     

Alcohol and aldehyde dehydrogenase genotypes and drinking behavior of Chinese living in Shanghai

Alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH), the principal enzymes responsible for oxidative metabolism of ethanol, exist in multiple, genetically determined molecular forms. Widely different kinetic properties in some of these isozymes account for the individual differences in alcohol sensitivity. In this study we used the polymerase chain reaction/restriction fragment length polymorphism method to determine the genotypes of the ADH2 and ALDH2 loci of alcoholic and nonalcoholic Chinese living in Shanghai. We also investigated the subjects' drinking patterns by means of semistructured interviews. The alcoholics had significantly lower frequencies of the ADH2² and ALDH2² alleles than did the nonalcoholics, suggesting the inhibitory effects of these alleles for the development of alcoholism. In the nonalcoholic subjects, ADH2² had little, if any, effect, despite the significant effect of the ALDH2² allele in decreasing the alcohol consumption of the individual. Taken together, these results fit the proposed hypothesis for the development of alcoholism, i.e., drinking behavior is greatly influenced by the individual's gentoypes of alcohol-metabolizing enzymes, and the risk of becoming alcoholic is proportionate with the ethanol consumption of the individual.     

Characterization of Methanosarcina mazeii TMA isolated from a paddy field soil

We isolated a methanogenic strain, designated as strain TMA (=DSM 9195), from an enrichment culture inoculated with a Japanese paddy field soil. Strain TMA was Gram positive and strictly anaerobic. Cell shape was pseudosarcina-like, and cells were nonmotile. The strain was able to use methylamines, methanol, H₂–CO₂, and acetate as substrates for methanogenesis, but did not utilize formate. The optimum temperature and optimum pH were 30–37°C and 6.5–7.5 respectively. The G+C content of the DNA was 42.1 mol %. Strain TMA had DNA-DNA hybridization values of more than 80% with Methanosarcina mazeii S-6^T (T = type strain). On the basis of phenotypic and genotypic characteristics, we identified strain TMA as M. mazeii. This is the first methylotrophic methanogen isolated from a paddy field soil and identified to the species level.     

Enzymic mechanism of starch breakdown in germinating rice seeds : 11. Ultrastructural changes in scutellar epithelium

The ultrastructural changes occurring in the scutellar epithelium cells of rice seeds have been studied during germination and early seedling growth. During this time, several prominent structural changes occur, including (a) formation, development, and proliferation of organelles such as mitochondria, rough endoplasmic reticulum, free ribosomes, and Golgi apparatus; (b) folded structural modification of plasmamembranes in later stages; and (c) conspicuous decrease in lipid-storing spherosomes. Glyoxysome-like electron dense particles are detectable but their formation is much less prominent. It is conceivable that all these structural changes are related to the enhancement of the metabolic activities of the epithelial cells including the synthesis of hydrolytic enzymes such as α-amylase and their secretion into the endosperm tissues. Some enzyme activities characteristic of mitochondria and glyoxysomes have been determined using the crude scutellar extracts, and the results dealing with the low activities of the glyoxylate cycle enzymes and palmitoyl-coenzyme A oxidase appear to indicate that fatty acid breakdown is possibly via mitochondrial β-oxidation, although we reserve a definitive conclusion on the glyoxysomes being nonfunctional in fatty acid oxidation in rice seedlings.     

Isolation and identification of substances inducing formation of tracheary elements in cultured carrot-root slices

Data are presented on the cytokinin status of seeds and seed components, at different stages of development in Phaseolus coccineus L., as determined with the soybean callus growth bioassay: A change in cytokinin types according to developmental stage occurred: from biologically very active less polar types (zeatin=Z) at early stages to more polar types (zeatin glucoside=Z₉G and zeatin riboside=Zr), with relatively low biological activity, at intermediate and late stages of seed development: When cytokinins were analyzed separately in embryos (embryo proper) and suspensors at two embryonic stages: heart-shaped (A) and middle cotyledonary embryos (stage B) respectively, it was found that: i) at stage A, the suspensor showed cytokinin activity at the level of Z, 2iPA (2-isopentenyladenosine) and Zr, whereas more polar cytokinins (Z₉G, Zr) were present in the embryo; ii) at stage B, when the embryo seems to become autonomous for cytokinin supply, there was a relative abundance of active cytokinins (Z, 2iPA) in the embryo to which Z₉G activity in the suspensor corresponded. It is concluded that the suspensor plays an essential role in embryogenesis by acting as a hormone source to the early embryo.Abbreviations GA gibberellic acid - 2iPA 2-isopentenyladenosine - Stage A heart-shaped embryo - siage B middle cotyledonary embryo - Z zeatin - Z₉G zeatin glucoside - Zr Zeatin riboside     

Anti-pituitary antibodies in patients with hypopituitarism and their families: longitudinal observation.

In an attempt to investigate the clinical significance of anti-pituitary antibodies in patients with hypopituitarism, anti-pituitary antibody in plasma was examined in 10 such patients (7 cases of isolated ACTH deficiency, 1 of partial hypopituitarism, and 2 of Sheehan's syndrome), on two or three occasions with an interval of more than 6 months (longitudinal study). In a total of 16 relatives of these 4 patients (2 cases of Sheehan's syndrome, one in each of partial hypopituitarism and isolated ACTH deficiency) and one patient not involved in the longitudinal study, anti-pituitary antibodies were also examined (family study). Anti-pituitary antibodies reacting with rat pituitary cytoplasmic antigens (pituitary cell antibodies: PCA) and pituitary cell surface antibodies (PCSA) reacting with GH3 cells and/or AtT-20 cells were measured with indirect immunofluorescence. The longitudinal study revealed the disappearance of antibodies in 3 patients, 2 PCA positive and one both PCA and PCSA positive. In 3 patients, altered antibody titers or a newly appearing antibody were found during the follow-up period. In 4 patients, the pituitary antibodies were negative during the follow-up periods. Of 16 family members studied, positive PCA was found in 3 members (2 in the families of patients with PCA positive Sheehan's syndrome, and 1 in the family of the patients with PCA positive partial hypopituitarism). Positive PCSA was found in 4 members (one in each of families of patients with partial hypopituitarism and isolated ACTH deficiency and of two cases of Sheehan's syndrome), and weakly positive PCSA was found in one family member of a patients with PCA positive Sheehan's syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)     

Contest and scramble competitions in two bruchid species,Callosobruchus analis andC. phaseoli (Coleoptera: Bruchidae)

Larval competition between contest and scramble strategists was investigated using the two bruchid species, C. analis (contest species) and C. phaseoli (scramble species) with two different sized mung beans (large and small beans). In both sized beans, the adult emergences of each species dependen on total density of the initial larval densities of the two species and the ratio of the two densities. The emergence of one species was suppressed by the existence of the other species when the initial larval density per bean of the former species was less than that of the latter one. There were many cases in which both C. analis and C. phaseoli emerged from one bean in large beans, but such cases were quite rare in small beans. C. analis performed interference behavior only at late larval stages, whereas C. phaseoli was superior in exploitative competition all through their larval stages. These, combined with the niche segregation inside a bean, are throught to be the major factors of observed density- and frequency-dependent competition results. Based on the above experimental results, long-term competition results between the contest and scramble species were predicted.     

A new type of mitogenic factor produced by Streptococcus pyogenes.

A new type of mitogenic factor (protein) was purified from the culture supernatant of a strain of Streptococcus pyogenes by SP-Sephadex C-25 column chromatography, preparative isoelectric focusing and reversed-phase high-performance liquid chromatography. The purified factor, showing marked mitogenic activity in rabbit peripheral blood lymphocytes, gave a single-band staining for protein on SDS-PAGE. The molecular weight of the purified mitogenic factor was determined to be 25,370, which was different from those calculated from reported amino acid sequences deduced from 4 different nucleotide sequences of 3 kinds of streptococcal pyrogenic exotoxins (two SPEAs, SPEB and SPEC). The amino acid sequence of the N-terminal region of the purified mitogenic factor was determined to be Gln-Thr-Gln-Val-Ser-Asn-Asp-Val-Val-Leu-Asn-Asp-Gly-Ala-Ser-Lys-Tyr-Leu- Asn-Glu - Ala-, which was also different from the reported N-terminal sequences deduced from the 4 different nucleotide sequences. These data indicate that this mitogenic factor is distinct from the already described streptococcal pyrogenic exotoxins.