Relation between enzyme release and metabolic changes in reversible anoxic injury of myocardial cells

Cultured adult cardiac myocytes were exposed to anoxia under substrate-free conditions. When compared to the metabolic changes in the oxygen deficient organ, those in the anoxic cell culture proceed in a similar, yet prolonged manner. Release of cytosolic enzymes starts with minor energetic disturbances and proceeds in close correlation to the actual ATP decay. Below 2 μmol. ATP/g_WW, an increasing number of cells becomes irreversibly damaged, but above, 30 min reoxygenation leads to extensive recovery of the whole preparation. The results indicate that leakage of cytosolic enzymes during the early stage of anoxia is due to a gradual protein release from the individual cells, related to reversible membrane alterations.     

Molecular organisation of the genes involved in the production of F7(2) fimbriae, causing mannose-resistant haemagglutination, of a uropathogenic Escherichia coli 06:K2:H1:F7 strain

Summary The genes responsible for the formation of the F7₂ fimbriae of the uropathogenic E. coli strain AD110 (O6:K2:H1:F7) have been cloned on the recombinant plasmid pPIL110-35 (Van Die et al. 1983). The F7₂ fimbriae, like the F7₁ fimbriae of AD110, are responsible for mannose resistant haemagglutination (MRHA).The molecular organisation of the genes of pPIL110-35 involved in the expression of MRHA was studied by: (a) analysis of transposon and Tn5 insertion mutants. Mutations that cause an MRHA-deficient phenotype were located in discrete groups within an 11.5 kb restriction fragment of pPIL110-35, separated by insertion mutations that do not inactivate MRHA. (b) complementation experiments. Restriction fragments of pPIL110-35 subcloned in the vector pBR322 were tested for their ability to complement transposon insertion mutations in the corresponding regions of pPIL110-35. Five complementation groups were distinguished.Five genes (designated A-E) involved in the expression of MRHA can be distinguished by these results. The products of these genes were analysed in minicells. The results indicate that gene B codes for a 75 K dalton protein, gene C for a 23 K dalton protein and gene E for a 36 K dalton protein. No product of gene D was observed. Gene A probably codes for the 17 K dalton subunit polypeptide of the F7₂ fimbriae, as will be discussed.     

Metabolism of indole-3-acetic acid and indole-3-methanol in wheat leaf segments

Indole-3-methanol is a product of indole-3-acetic acid metabolism in wheat leaves ( Triticum compactum Host., cv. Little Club). It leads either to the production of the corresponding aldehyde and carboxylic acid, to the production of a polar glucoside which releases indole-3-methanol on β-glucosidase treatment, or to an unidentified apolar product on mild alkaline hydrolysis in aqueous methanol. With reference to a published pathway of indole-3-acetic acid degradation, the results provide evidence for a prominent role of indole-3-methanol and also for the occurrence of co-oxidation processes in wheat leaves involving indole-3-acetic acid and phenolic cosubstrates.     

Diffusion and regionalization in membranes of maturing ram spermatozoa

An essential feature of the "fluid mosaic model" (Singer, S. J., and G. L. Nicolson , 1972, Science (Wash. DC)., 175:720-731) of the cell plasma membrane is the ability of membrane lipids and proteins to diffuse laterally in the plane of the membrane. Mammalian sperm are capable of overcoming free random diffusion and restricting specific membrane components, both lipid and protein, to defined regions of the sperm's surface. The patterns of these regionalizations evolve with the processes of sperm differentiation: spermatogenesis, epididymal maturation, and capacitation. We have used the technique of fluorescence recovery after photobleaching to measure the diffusion of the lipid analogue 1,1'- dihexadecyl 3,3,3',3'- tetramethylindocarbocyanine perchlorate ( C16dil ) on the different morphological regions of testicular and ejaculated ram spermatozoa. We have found: (a) that the major morphologically distinct regions (head, midpiece, and tail) of the plasma membrane of both testicular and ejaculated spermatozoa are also physically distinct as measured by C16dil diffusibility; (b) that despite regional differences in diffusibility there is exchange of this lipid analogue by lateral diffusion between the major morphological regions of the plasma membrane; and (c) that epididymal maturation results in changes in C16dil diffusibility in the different regions of the sperm plasma membrane. In particular, the plasma membranes of the anterior and posterior heads become physically distinct.     

New derivatization and separation procedures for reducing oligosaccharides

4-Trifluoroacetamidoaniline was reacted with reducing oligosaccharides in the presence of sodium cyanoborohydride to give aminoalditol derivatives, useful for linkage to proteins or solid matrices. A mixture of reducing oligosaccharides, difficult to separate by HPLC, was treated in the same way. The resulting derivatives were easily separated by HPLC.Abbreviations TFAN 4-trifluoroacetamidoaniline - LcOse₄ lacto-N-tetraose - IV²Fuc-LcOse₄ lacto-N-fucopentaose l - III⁴Fuc-LcOse₄ lacto-N-fucopentaose II - III³Fuc-nLcOse₄ lacto-N-fucopentaose III - IV²Fuc, III⁴Fuc-LcOse₄ lacto-N-difucohexaose I - II⁶Galß1-4GlcNAc-LcOse₄ lacto-N-hexaose - II³NeuAc-Lac 3-sialyllactose - GlcNAcß1-4GlcNAcß1-4GlcNAc chitotriose - GalNac1-3|Fuc1-2|Galß1-4Glc A-tetrasaccharide     

Noncyclic electron transport in chromatophores from photolithotrophically grown Rhodobacter sulfidophilus

Chromatophores isolated from the marine phototrophic bacterium Rhodobacter sulfidophilus were found to photoreduce NAD with sulfide as the electron donor. The apparent K _m for sulfide was 370 M and the optimal pH was 7.0. The rate of NAD photoreduction in chromatophore suspensions with sulfide as the electron donor (about 7–12 M/h·mol Bchl) was approximately onetenth the rate of sulfide oxidation in whole cell suspensions. NAD photoreduction was inhibited by rotenone, carbonyl cyanide-m-chlorophenylhydrazone, and antimycin A. Sulfide reduced ubiquinone in the dark when added to anaerobic chromatophore suspensions. These results suggest that electron transport from sulfide to NAD involves an initial dark reduction of ubiquinone followed by reverse electron transport from ubiquinol to NAD mediated by NADH dehydrogenase.Abbreviations Bchl bacteriochlorophyll - CCCP carbonyl cyanide-m-chlorophenylhydrazone - MOPS 3(N-morpholino)-propane sulfonate - Uq ubiquinone     

Temporal Distribution of [3H]-Imipramine Binding in Rat Brain Regions is Not Changed by Chronic Methamphetamine

Specific binding of [³H]-imipramine in the rat suprachiasmatic nuclei, occipital cortex and caudate putamen underwent significant and replicable changes throughout 24 hr under a light-dark cycle or under constant conditions. Daily variations were also found in the medial and dorsal raphe nuclei and the lateral hypothalamus. Methamphetamine, a psychoactive drug with marked effect on circadian rhythms in physiological and hormonal parameters and adrenergic receptors, did not have any significant effect on imipramine binding rhythms in eight discrete brain regions. Thus a drug known to reduce serotoninergic neurotransmission did not change characteristics of the modulatory binding site related to serotonin uptake.