Muscarinic cholinergic and preganglionic physiological stimulation increase cyclic GMP levels in guinea-pig superior cervical ganglia.

Abstract— Incubation of guinea-pig superior cervical ganglia in 500μ4mUm -carbachol for 2min increased cyclic GMP levels 530% over control values. The increase was blocked by prior incubation in 300μm atropine. No increase in cyclic GMP levels after incubation in 100 μm -l -norepinephrine was observed. Preganglionic physiological stimulation for 8 min at 10 Hz increased cyclic GMP levels 180% over control values. We conclude that both muscarinic cholinergic and preganglionic physiological stimulation increase cyclic GMP levels in guinea pig superior cervical ganglia, while norepinephrine has no effect.     

Comparison of microbial counts on beef carcasses by using the moist-swab contact method and secondary tissue removal technique.

When a tissue removal rinse technique was compared to the moist-swab contact method, significantly greater numbers of bacteria were recovered from beef carcasses, especially when the flora exceeded log10 4.5/6.45 cm2. Secondary treatment of the removed surface tissue by blending resulted in a significantly greater number of bacteria being recovered than when the same sample was swabbed and/or rinsed. Data indicate that blending of the carcass surface tissue provides a more representative value of the true microbial flora.     

The annual lipid cycle and feeding behavior of Alaskan redpolls

Summary Total lipids were extracted from 161 redpolls (Acanthis spp.) collected each month of the year from October 1962 to September 1963, in interior Alaska. A lipid index (Weight of ether extract x100/live body weight) was calculated for each sample. Lipids were also extracted from sections of pectoral muscle, livers and hearts representing each month.Body weight and lipid index were significantly positively correlated being highest in January and lowest in September. Total lipid content was significantly inversely correlated with air temperature; the high autumn and spring pre-migratory lipid peaks of migratory species were only weakly expressed in the redpolls. Liver lipid showed a significant annual variation being highest in December and lowest in August, while lipid from heart and pectoral muscle did not vary seasonally.Five birds were held in captivity during spring and summer at a constant temperature of 22°C. Food consumption was 5.1 g/day or 22.4 kcal. The caloric value of the most extensively utilized natural food, birch seed (Betula papyrifera), was determined (5.4–5.5 kcal/g dry wt). When esophageal diverticulae are full (2.0 g wet wt) of birch seeds, the resulting energy yield may sustain an individual for only a fraction of a 24 h winter day in contrast to other arctic herbivores (e.g. ptarmigan, Lagopus sp.) in which a full crop may suffice for the full 24 h period.     

Drug residue formation from ronidazole, a 5-nitroimidazole. III. Studies on the mechanism of protein alkylation in vitro

Ronidazole (1-methyl-5-nitroimidazole-2-methanol carbamate) is reductively metabolized by liver microsomal and purified NADPH-cytochrome P-450 reductase preparations to reactive metabolites that covalently bind to tissue proteins. Kinetic experiments and studies employing immobilized cysteine or blocked cysteine thiols have shown that the principal targets of protein alkylation ara cysteine thiols. Furthermore, ronidazole specifically radiolabelled with 14C in the 4,5-ring, N-methyl or 2-methylene positions give rise to equivalent apparent covalent binding suggesting that the imidazole nucleus is retained in the bound residue. In contrast, the carbonyl-14C-labeled ronidazole gives approx. 6--15-fold less apparent covalent binding indicating that the carbamoyl group is lost during the reaction leading to the covalently bound metabolite. The conversion of ronidazole to reactive metabolite(s) is quantitative and reflects the amazing efficiency by which this compound is activated by microsomal enzymes. However, only about 5% of this metabolite can be accounted for as protein-bound products under the conditions employed in these studies. Consequently, approx. 95% of the reactive ronidazole metabolite(s) can react with other constituents in the reaction media such as other thiols or water. Based on these results, a mechanism is proposed for the metabolic activation of ronidazole.     

A numerical taxonomic study of species of Vibrio isolated from the aquatic environment and birds in Kent, England

A numerical taxonomic study has been carried out to confirm the identity of strains of the family Vibrionaceae isolated during an ecological study. A total of 237 strains were studied including 148 from the aquatic environment, 6 from estuarine birds, 1 from sheep faeces, and 61 control cultures. Duplicates of 21 of the strains were randomly selected and included to estimate test and operator error. Taxonomic resemblance was estimated on the basis of 148 characters using Euclidean distance. The taxonomic position of some strains was reevaluated using the pattern difference coefficient. Strains were clustered by three methods, all of which gave similar results. The estimated average probability of test error was 1.5%. Strains previously identified as Vibrio anguillarum fell into four distinct phenons corresponding to V. anguillarum biovar I, ' V. anguillarum biovar II', V. diazotrophicus , and strains pathogenic to oyster larvae. The latter group characteristically degraded xanthine and probably represents a new species. The phenon corresponding to V. cholerae included the type strain, strains of human origin, and strains isolated in the United Kingdom from birds and the aquatic environment. Some strains of V. cholerae were luminous. Other phenons were identified as V. metschnikovii, V. fluvialis , and Aeromonas spp.     

Characterization of a cytosolic fucosylation pathway in Dictyostelium.

FP21 is a 21-kDa fucoprotein which fractionates with the cytosol after high-speed centrifugation of gently lysed Dictyostelium cells. Less than 0.7% of FP21 is associated with vesicles. In proliferating cells, 4 x 10(5) fucosyl moieties/cell are associated with FP21 as anionic, possibly O-linked oligosaccharides equal in size to 4.8 glucose units. FP21 is underfucosylated in a mutant strain (HL250) that depends on extracellular fucose for synthesis of GDP-fucose. To determine the cellular site of FP21 fucosylation, cytosolic and vesicular preparations from strain HL250 were compared for their ability to transfer fucose from GDP-fucose to FP21. Cytosolic preparations fucosylate endogenous FP21 in a time-, concentration-, and divalent cation-dependent fashion, with a Km for GDP-fucose of 1.4 microM. Activity in normal cell cytosol is dependent on exogenous mutant FP21, demonstrating that FP21 is normally fully fucosylated. Both mutant and normal cytosols are also able to alpha-fucosylate a type 1 glycolipid substrate (8-methoxycarbonyloctyl-Gal beta 1-3 beta GlcNAc), but not related substrates, with Km values for the type 1 glycolipid of 0.99 mM and for GDP-fucose of 1.6 microM. Competitive inhibition between FP21 and the type 1 glycolipid shows that the same enzyme fucosylates both substrates. Intact and permeabilized vesicle preparations from wild-type cells are unable to fucosylate FP21 or the type 1 glycolipid by a divalent cation-dependent mechanism, and thus are devoid of FP21-fucosyltransferase. Since control experiments showed that vesicle leakage is minimal during cytosol preparation, these results indicate that FP21 is synthesized and fucosylated in the cytosolic compartment, by an unusual soluble fucosyltransferase.     

Protection against acute paraquat toxicity by ambroxol

An expression vector for G-CSF, pASLB3-3, was constructed and introduced into Namalwa KJM-1 cells (Hosoi et al., 1988), and cells resistant to 100 nM of methotrexate (MTX) were obtained. Among them, the highest producer, clone SC57, was selected and the productivity of this clone was further characterized. The maximal production of G-CSF was at the most 1.8 g/ml/day using a 25 cm² tissue culture flask, even though the cell number was above 7×10⁵ cells/ml. The limiting factors at high density were analyzed as the deficiency of nutrients, such as glucose, cysteine and serine, and pH control. The depression of specific G-CSF productivity per cell under the batch culture conditions was overcome by using a perfusion culture system, Biofermenter^TM (Sato, 1983) with modifications of nutrients supplementation by a dialysis membrane and/or dissolved oxygen (DO) supplementation by microsilicone fibers. ITPSGF medium was modified to elevate concentrations of amino acids and glucose by 2.0- and 2.5-times, respectively. Under the control of pH at 7.4 and DO at 3 ppm, the specific G-CSF productivity was not depressed even at high cell density (above 1×10⁷ cells/ml), and the amount of G-CSF reached 41 g/ml. These results indicated the possibility of finding the optimum culture conditions for the production of recombinant proteins by Namalwa KJM-1 cells.Abbreviations ABTS 2,2-Azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid - BSA Bovine Serum Albumin - BSA-PBS Phosphate-buffered Saline without Ca²⁺ and Mg²⁺ containing Bovine Serum Albumin - dhfr Dihydrofolate Reductase - DO Dissolved Oxygen - G-CSF Granulocyte Colony-stimulating Factor - HEPES 4-(2-Hydroxyethyl)-1-piperazineethansulfonic Acid - IFN Interferon - MTX Methotrexate - PBS(-) Phosphate-buffered saline without Ca²⁺ and Mg²⁺ - Tween-PBS Phosphate-buffered saline without Ca²⁺ and Mg²⁺ containing 0.05% of Tween 20     

Germination and growth of cultivars ofTrifolium subterraneum L. in the presence of sodium chloride salinity

Summary Germination and growth responses of 15 early to midseason cultivars ofTrifolium subterraneum L. were determined at a range of irrigation water salinities (NaCl). There were significant cultivar differences in seed germination under standard conditions in the presence of pure solutions of NaCl from −10 to −330 kPa osmotic potential range. There were also significant cultivar differences in growth on a clay loam soil with increasing NaCl over the same range of osmotic potentials as used to test germination. There was a generally poor correlation between salt tolerance at germination and at later stages of growth.