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Biomedical subjects

E Galun

Publications and source records attributed to E Galun.

At least 109 records · Page 6Linked to original sources

Glucose and glycine metabolism in regenerating tobacco protoplasts: followed nondestructively by nuclear magnetic resonance spectroscopy.

The metabolic states and the uptake and metabolism of [1-(13)C]glucose, [2-(13)C]glycine, and [(15)N]glycine in intact Nicotiana tabacum L. (cv Xanthi) mesophyll protoplasts were measured by (13)C and (15)N nuclear magnetic resonance spectroscopy. Changes in the concentration of metabolites during the first two days of culture in darkness were followed. Protoplasts isolated in 0.55 molar mannitol medium showed a drop in the concentration of all the intracellular metabolites during the first 28 hours of culture. Uptake of glucose and synthesis of glucose-derived metabolites were observed, indicating activity of glycolysis and the tricarboxylic acid cycle. Addition of glycine caused the accumulation of serine in dark cultured protoplasts, via the photorespiratory pathway. Glutamate dehydrogenase and glutamine synthetase activities in photorespiratory NH(4) (+) assimilation were observed. Glucose uptake and metabolism and cell division were inhibited by 3 millimolar glycine, suggesting that the accumulating serine or the release of ammonia during serine synthesis had toxic effects in this system.

Journal Article↗

Quinidine-induced vasculitis.

Four patients developed nonthrombocytopenic purpura two to three weeks after initiation of quinidine therapy. The skin lesions disappeared and did not recur after cessation of quinidine therapy. Histologic examination revealed leukocytoclastic vasculitis with deposition of C3, IgA, and/or IgM in the small dermal vessels. Since quinidine purpura is usually associated with thrombocytopenia, the possibility of leukocytoclastic vasculitis as an additional cause of purpura is stressed.

Aged↗

Serum creatine kinase activity following a 120-km march.

Serum creatine kinase (SCK) was measured in 19 well-trained athletes before, immediately after and 24 and 72 h after a 120-km, non-stop march. The mean level before the march was 97.6 +/- 46.6 (SD), immediately after the march 1072.8 +/- 708 microns/l, and 72 h later 185.6 +/- 106.2 microns/l. It is concluded that elevated SCK levels may persist for 72 h after a long march.

Adult↗

Cytoplasmic hybridization in Nicotiana: mitochondrial DNA analysis in progenies resulting from fusion between protoplasts having different organelle constitutions.

Our previous studies indicated that fusion products with one functional nucleus but organelles of the two fusion partners (i.e. heteroplastomic cybrids) could be obtained by fusing X-irradiated (cytoplasmic donor) with non-irradiated (recipient) Nicotiana protoplasts. The present report deals with the analysis of mitochondria in cybrid populations resulting from the fusion of donor Nicotiana tabacum protoplasts with recipient protoplasts having a N. Sylvestris nucleus but chloroplasts of an alien Nicotiana species, and exhibiting cytoplasmic male sterility. The two fusion parents showed significant differences in restriction patterns of their chloroplast and mitochondrial DNA. Four groups of cybrid plants were obtained by this fusion. All had N. sylvestris nuclei but contained either donor or recipient chloroplasts and had either sterile or fertile anthers. There was no correlation between anther fertility and chloroplast type. The mitochondrial DNA restriction patterns of sterile cybrids were similar to the respective patterns of the sterile fusion partner while the mitochondrial DNA restriction patterns of the fertile cybrids were similar to the respective patterns of the fertile fusion partner. The results indicate an independent assortment of chloroplasts and mitochondria from the heteroplastomic fusion products.

Cell Fusion↗

Hyphal walls of isolated lichen fungi: autoradiographic localization of precursor incorporation and binding of fluorescein-conjugated lectins.

The hyphal walls of three mycobionts, isolated from the lichens Xanthoria parietina, Tornabenia intricata and Sarcogyne sp. were investigated by two techniques: microautoradiography of fungal colonies exposed to radioactive carbohydrate precursors: and binding, in vivo, of fluorescein conjugated lectins to hyphal walls of such colonies. N-[3H] acetylglucosamine was readily incorporated into tips, young hyphal walls and septa of the three mycobionts and the free-living fungus Trichoderma viride, but not into Phytophthora citrophthora, indicating that chitin is a major component of the mycobionts' hyphal walls. All three mycobionts, but neither of the free-living fungi, incorporated [3H] mannose and [3H] mannitol into their hyphal walls. Fluorescein-conjugated wheat germ agglutinin was bound to the hyphal walls of the three mycobionts and T. viride, but not to the walls of P. citrophthora; the binding pattern was similar to the grain pattern obtained in autoradiographs after short N-[3H]acetylglucosamine labelling. As wheat germ agglutinin binds specifically to chitin oligomers, the lectin binding tests further confirmed that chitin is a mycobiont hyphal wall component. Binding characteristics of several fluorescein-conjugated lectins to the three mycobionts indicated that this technique can yield useful information concerning the chemical composition of hyphal wall surfaces.

Acetylglucosamine↗

Immunochemical studies on tyrosinase induction in Neurospora.

An immunoassay for tyrosinase, using the modified bacteriophage technique, was developed: Tyrosinase of Neurospora was conjugated to bacteriophage T4 using glutaraldehyde as a cross-linking agent. The conjugated phage that survived the coupling process could be inactivated by antiserum raised in rabbits against pure tyrosinase, but not by normal serum. This inactivation was specifically inhibited by pure Neurospora tyrosinase, and the degree of inhibition was proportional to the concentration of tyrosinase within the range of 30-150 ng/ml. Crude mycelial extract possessing tyrosinase activity could similarly inhibit the inactivation of the conjugated phage by the antiserum. To evaluate the tyrosinase content of crude extracts their inhibitory capacity was compared to that of known amounts of pure tyrosinase, and the amounts thus calculated agreed with those predicted from an enzymatic assay. The tyrosinase-bacteriophage immunoassay was used for the quantitation of tyrosinase-antigen in crude extracts of Neurospora cultures that had been induced to form tyrosinase by the addition of ethionine. Enzymatic activity appeared after a lag of several hours, increased for 2-3days and then declined. Immunological assays of these cultures showed: (a) serologically reactive protein started to accumulate upon culture starvation and was evident during the lag period; (b) specific activity (units per mg antigen) was constant throughout induction; (c) at the phase of decrease in mycelial enzyme content, increasing amounts of serologically reactive protein were detected in the medium, indicating that some enzyme was eventually excreted. These results show that the lag is not a qualitatively distinct period, and support the previously forwarded notion that tyrosinase is synthesized de novo upon induction.

Antigen-Antibody Reactions↗

Characterization of polyadenylate from the fungus Trichoderma viride.

Polyribonucleotide segments, about 60 nucleotides long and consisting of about 95% adenylic acid residues, were isolated from whole cell ribonucleic acid of the deuteromyceteous fungus Trichoderma viride. Similar findings in two other groups of the true fungi raise the possibility that short polyadenylate sequences may be a feature of these relatively simple organisms.

Adenine Nucleotides↗