Mouse {beta}-galactoside {alpha}2,3-sialyltransferases: comparison of in vitro substrate specificities and tissue specific expression

Four types of ß-galactoside     

Unique tissue distribution of a mouse macrophage C-type lectin

We examined mouse tissue for the expression of macrophage galactose/N-acetylgalactosamine-specificC-type lectin using a rat monoclonal antibody (mAb) specificfor this lectin (mAb LOM-14). The binding of mAb LOM-14 wasdetected in detergent extracts from tissue by means of immunoblottinganalysis. It was shown that this mAb did not cross-react withmouse hepatic lectins, a structural homologue. The macrophagelectin was widely distributed among various mouse tissues asjudged by the affinity isolation followed by the immunochemicaldetection. The exceptions were brain, liver, kidney, small intestine,and peripheral blood. Extracts from these organs exhibited,at best, very weak signals upon mAb LOM-14 binding, despitethe presence of cells expressing macrophage markers. The mostintense signal was observed in the extract from skin, suggestingthat cells expressing this lectin are abundant in skin. Thetissues shown to contain this lectin were further investigatedby immunohistochemical staining of the sections. Cells weredistributed in the connective tissue and in the interstice,particularly the dermis and subcutaneous layer of skin. Cellslocalized in the epithelium of skin (epidermis) or other epitheliathat we examined were not stained. Perivascular localizationof cells stained with mAb LOM-14 was also demonstrated in cardiacand skeletal muscle tissues. Immunoelectron microscopy revealedthe presence of this lectin along the rough endoplasmic reticulum.In conclusion, the distribution of C-type lectin specific forgalactose/N-acetylgalactosamine in mice was unique. The connectivetissue-specific distribution should provide important informationon the biological role of this lectin. lectin macrophage calcium-type lectin connective tissue     

In vitro microsome-mediated aflatoxin B1-DNA binding and its inhibition by cytosol of various organs of the hamster and quail

We studied thein vitro activation of aflatoxin B1 (B1) by microsomes and its inactivation by the cytosol of various quail and hamster organs, using B1-DNA binding as an index. The microsomal activity of the liver to bind B1 to DNA was not largely different between the two species and was higher than that of the other organs examined in either species. The microsomal activity of the kidney and lung was very low in the quail compared with the hamster, indicating the very small contribution of the lung and kidney microsomes to the activation of B1 in birds. Only the hamster liver cytosol showed strong inhibition of microsome-mediated B1-DNA binding.     

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.     

Partial characterization of the glucose transport activity in the golgi-rich fraction of fat cells

The glucose transport activity solubilized from the basal and plus insulin forms of the Golgi-rich fraction of adipocytes was partially characterized, and the results were compared with those of the activity obtained from the plus insulin form of the plasma membrane-rich fraction. The transport activity was determined in a cell-free, reconstituted, system. Prior to reconstitution, the activities in the three preparations were all (a) stable at 0°C for at least 4 h, but not at 37°C or above; (b) most stable at pH 7–9, and (c) less stable in Tes than in Tris buffer. After reconstitution, the three activities were all (d) stable at 0°C, (e) most active at pH 5.5, (f) mildly stimulated by divalent cations, (g) unaffected by insulin or 1 mM of several SH-blocking agents, (h) inhibited by heavy metal ions, 10–100 mM of monovalent salts, organic solvents, several sugar isomers, and specific sugar-transport inhibitors. The rates of d-glucose uptake by the three liposome preparations were all inhibited more strongly by 2-deoxy-d-glucose or $\text{3}\text{-O-}\text{methyl-}\text{d}\text{-glucose}$ than by d-glucose. These data indicate that the general properties of the glucose transport activity in the Golgi-rich fraction are similar to those of the activity in the plasma membrane-rich fraction.     

Oxygen Enhancement of bactericidal activity of rifamycin SV on Escherichia coli and aerobic oxidation of rifamycin SV to rifamycin S catalyzed by manganous ions: the role of superoxide

Oxygen enhanced the bactericidal activity of rifamycin SV to Escherichia coli K12. Anaerobically grown cells, which had a low level of superoxide dismutase, were more susceptible to the bactericidal activity than aerobically grown cells, which contained a high level of superoxide dismutase. Oxygen also enhanced the inhibition of RNA polymerase activity of rifamycin SV, when Mn2+ was used as a cofactor. Rifamycin S was reduced to rifamycin SV by NADPH catalyzed by cell-free extracts of Escherichia coli K12. These results indicate that the inhibition of bacterial growth by rifamycin SV is due to the production of active species of oxygen resulting from the oxidation-reduction cycle of rifamycin SV in the cells. The aerobic oxidation of rifamycin SV to rifamycin S was induced by metal ions, such as Mn2+, Cu2+, and Co2+. The most effective metal ion was Mn2+. In the presence of Mn2+, accompanying the consumption of 1 mol of oxygen and the oxidation of 1 mol of rifamycin SV, 1 mol of hydrogen peroxide and 1 mol of rifamycin S were formed. Superoxide was generated during the autoxidation of rifamycin SV. Superoxide dismutase inhibited the formation of rifamycin S, but scavengers for hydrogen peroxide and the hydroxyl radical did not affect the oxidation. A mechanism of Mn2+-catalyzed oxidation of rifamycin SV is proposed and its relation to bactericidal activity is discussed.     

A Comparison of Purified Host Specific Toxin from Helminthosporium maydis, Race T, and Its Acetate Derivative on Oxidation by Mitochondria from Susceptible and Resistant Plants

NADH or succinate oxidation and malate oxidation were differentially affected in mitochondria from both susceptible and resistant corn by a purified and chemically characterized preparation of host-specific toxin from Bipolaris (Helminthosporium) maydis, race T. NADH and succinate oxidation by susceptible T corn mitochondria were stimulated 50 to 200% with apparent uncoupling from the cytochrome chain at approximately 10(-9)m toxin (5 to 20 ng/ml). Significant inhibition of malate oxidation was observed at slightly higher toxin concentrations, but oxidation was still coupled to ADP utilization. Inhibition of malate oxidation also was observed in N corn (resistant) and soybean mitochondria at approximately 1,000-fold greater concentrations, but stimulation of NADH and succinate oxidation was not found at any toxin concentration tested.A fully acetylated toxin derivative at approximately 1 microgram per milliliter also caused stimulation of NADH or succinate oxidation in T corn mitochondria, but not those of N corn or soybean mitochondria at 100 micrograms per milliliter. Malate oxidation was inhibited to the same extent by toxin acetate with mitochondria from T corn, N corn, and soybean. The blocking of hydroxyl groups in race T toxin by acetyl functions eliminated selectivity toward malate oxidation only. The data suggest that inhibition of malate oxidation is either a separate or secondary effect of selective action of toxin on T corn mitochondria, perhaps by interference with transport in or out of the matrix. Sensitivity of T, but not N, corn mitochondria to purified toxin decays within minutes after pellets are suspended in aqueous osmotica, with no obvious change in mitochondrial integrity. The action of race T toxin seems to involve a labile process, such as ion gradient(s), or an unstable structural conformation of T corn mitochondria.     

Pili mediated agglutination of Serratia marcescens in human urine

Of 51 strains of Serratia marcescens isolated from patients with urinary or respiratory tract infections, 35 agglutinated in human urine. The agglutinating strains possessed numerous pili which were morphologically distinct from common pili or type I pili. The diameter of the pili was 3 nm and the average length was 0.3 micrometer. Electron microscopic examination showed that 80% or more of the cells of the agglutinating strains and 0 to 8% of the cells of the nonagglutinating strains were piliated. When an agglutinating strain was heated at 55 C for 10 min, it lost its agglutinating capacity and concomitantly its pili. These results suggest that the agglutination might occur because of interactions between the pili and some factors in human urine. The urinary slime appears to contain these agglutinating factors.