Studies on a virus isolated from the brain of a parakeet (Neophema sp)

Haemagglutinating viruses were isolated from Australian parakeets and from aviary birds of the order Passeriformes. In all cases the affected birds showed symptoms of disease of the nervous system. One of the isolates, 449, has the physico-chemical and biological properties of the paramyxoviruses. Comparative serological and animal-experimental investigations suggested that this isolate could be a deviating strain of Newcastle disease virus.     

Production of an extracellular thermohalophilic lipase from a moderately halophilic bacterium, Salinivibrio sp. strain SA-2

Fifty strains of moderately halophilic bacteria were isolated from various salty environments in Iran. A strain designated as SA-2 was shown to be the best producer of extracellular lipase and was selected for further studies. Biochemical and physiological characterization along with 16S rDNA sequence analysis placed SA-2 in the genus Salinivibrio. The optimum salt, pH, temperature and aeration for enzyme production were 0.1 M KCl, pH 8, 35 degrees C and 150 rpm, respectively. The enzyme production was synchronized bacterial growth and reached a maximum level during the early-stationary phase in the basal medium containing 1 M NaCl. Triacylglycerols enhanced lipase production, while carbohydrates had inhibitory effects on it. The maximum lipase activity was obtained at pH 7.5, 50 degrees C and CaCl(2) concentration of 0.01 M. The enzyme was stable at pH range of 7.5-8 and retained 90% of its activity at 80 degrees C for 30 min. Different concentrations of NaNO(3), Na(2)SO(4), KCl and NaCl had no affect on lipase stability for 3 h. These results suggest that the lipase secreted by Salinivibrio sp. strain SA-2 is industrially important from the perspective of its tolerance to a broad temperature range, its moderate thermoactivity and its high tolerance to a wide range of salt concentrations (0-3 M NaCl).     

Studies on the depression of gamma-aminobutyric acid potentials by phloridzin in cat dorsal root ganglion cells in vitro

Phloridzin has been used as a tool to investigate membrane transport mechanisms. We have demonstrated that phloridzin acts to depress chloride flux resulting from activation of a gamma-aminobutyric acidA (GABAA) receptor on cat dorsal root ganglion cells. This action appears not to involve an inwardly directed chloride pump postulated for these neurons but rather affects a site associated with the GABA receptor-chloride complex.     

Studies on the derivatives of thiazole acetic acid. II. Syntheses and pharmacological analysis of 2-N-aralkylidene and 2-N-aralkyl derivatives of 2-amino-4-p-chlorophenylthiazole-5-acetic acid.

A number of 2-N-aralkylidene, 2-N-aralkyl and 2-N-aralkyl-alpha-sulphoderivatives of 2-amino-4-p-chlorophenylthiazole-5-acetic acid (I, R = H) and its methyl ester (I, R = CH3) were synthesized. As a result of condensation of methyl ester I with various aromatic aldehydes in boiling benzene solution, the Schiff-bases (anils) II--VIII were obtained. After reduction with NaBH4 compounds II--VIII were transformed into adequate amino esters IX--XV. Esters IX--XV heated with diluted aqueous solution of sodium hydroxide underwent selective hydrolysis giving the respective amino acids XVI--XXII. Some of Schiff bases (II, III, V, VII, VIII) reacted with aqueous alcoholic solution of sodium bisulphite after its several (XXIII--XXVII). alpha-sulphoderivatives had been obtained. Several tests were performed in order to detect the anti-inflammatory and immunosuppressive activity of the compounds. The pharmacological analysis allowed us to draw conclusions concerning the relationship between chemical structure and biological activity in this group of compounds. The most efficacious immunosuppressive and anti-inflammatory activity exhibited 2-aralkyl-alpha-sulphoderivatives.     

Induction of apoptosis by dideoxypetrosynol A, a polyacetylene from the sponge Petrosia sp., in human skin melanoma cells

Dideoxypetrosynol A, a polyacetylene from the sponge Petrosia sp., is known to exhibit significant selective cytotoxicity against several human tumor cell lines. In the present study, we investigated the possible mechanisms by which dideoxypetrosynol A exerts its anti-proliferative action in cultured human SK-MEL-2 skin melanoma cells. Exposure of SK-MEL-2 cells to dideoxypetrosynol A resulted in growth inhibition and induction of apoptosis in a dose-dependent manner as measured by MTT assay, fluorescent microscopy and flow cytometry analysis. The increase in apoptosis was associated with a dose-dependent up-regulation in proapoptotic Bax expression and down-regulation of anti-apoptotic Bcl-2. Apoptosis-inducing concentrations of dideoxypetrosynol A induced caspase-3 and caspase-9 activation accompanied by proteolytic degradation of poly(ADP-ribose)-polymerase and selective down-regulation of cIAP-1. Taken together, these findings provide important new insights into the possible molecular mechanisms of the anti-cancer activity of dideoxypetrosynol A.     

Studies on renin release from isolated superfused glomeruli: effects of temperature, urea, ouabain and ethacrynic acid.

1. The effects of different energy substrates, of low temperature, of urea, and of ouabain and ethacrynic acid were studied on the rate of renin release from viable juxtaglomerular cells during superfusion of isolated rat glomeruli. 2. Neither lactate nor glutamate altered renin release rate from that observed using glucose as the sole energy substrate. Succinate 10 mM elevated release transiently but did not influence the release caused by reductions in osmolality through lowering sucrose concentration. 3. Peak renin release was more prolonged and returned more slowly to control following reductions in osmolality in phosphate-Ringer than in bicarbonate-Ringer. 4. At 37 degrees C, the peak of renin released induced by hypo-osmolality was smaller and delayed, and returned earlier to control than at 30 degrees C. Reduction in temperature from 30 to 4 degrees C resulted in a 32-fold increase in basal release rate. At 4 degrees C a 20 m-osmole/kg reduction in tonicity caused an additional 2-5-fold increase in release rate. 6. Increasing superfusate osmolality with urea did not affect basal renin release but 100 mM urea suppressed the releasing effect of a 15 mM reduction in NaCl concentration. 7. Ouabain (10(-4) M) caused a small (33 +/- 9%, P less than 0-025) transient increase in renin release. Ethacrynic acid (10(-3) M) provoked a progressive increase in release reaching 100 +/- 15% above control within 50 min. In the presence of both inhibitors the release provoked by hyposmolality was prolonged. 8. It is concluded that renin release in vitro is a function of actively regulated cell volume and it is proposed that a similar mechanism could underline both barorecptor and macula densa controls of renin secretion in vivo.     

Production of cholera-like enterotoxin by a Vibrio cholerae non-O1 strain isolated from the environment.

Vibrio cholerae non-O1 strain E8498, isolated in 1978 from fresh water in Louisiana, produced a vascular permeability factor when cultured in shallow resting cultures of Casamino Acids-yeast extract-glucose medium for 24 h at 30 degrees C. Undiluted resting culture filtrates contained heat-labile permeability factor activity which was only partially neutralized by cholera antitoxin and GM1 ganglioside. Supernatants concentrated with PM-10 membranes caused hemorrhage and necrosis in rabbits within 1 h after intracutaneous injection, whereas appropriate dilutions of both filtrates and concentrates demonstrated delayed permeability factor activity, without hemorrhage or necrosis, which was indistinguishable in appearance from that caused by purified cholera enterotoxin produced by V. cholerae O1 Inaba strain 569B. Crude E8498 filtrates contained the biological equivalent of about 5 ng/ml of purified enterotoxin. Permeability factor activity in the fraction obtained by 20 to 50% saturation of filtrate concentrate with ammonium sulfate could be completely neutralized by reference standard cholera antitoxin prepared against purified 569 B enterotoxin. Hemorrhagic activity was unaffected by cholera antitoxin. A 5,000-fold concentrate of the culture supernatant yielded a line of identity with purified cholera enterotoxin in an agar gel double-diffusion test against cholera antitoxin purified by affinity column chromatography with BrCN-activated Sepharose 4B-linked purified cholera enterotoxin as the adsorbent. These findings indicate that V. cholerae non-O1 E8498 produces a permeability factor which is immunologically and biologically indistinguishable from that produced by a strain of V. cholerae O1 classical biotype.     

Phylogenetic characterization of a microsporidium (Endoreticulatus sp. Zhenjiang) isolated from the silkworm, Bombyx mori

This study examined the morphological and molecular characteristics of the microsporidium Endoreticulatus sp. Zhenjiang, isolated from the silkworm (Bombyx mori). The fresh spores were oval, 2.9 ± 0.2 μm in length and 1.2 ± 0.2 μm in width. The complete rRNA cistron has a length of 4,432 bp (GenBank accession no. FJ772431), including the large subunit rRNA (2,460 bp), the internal transcribed spacer (187 bp), the small subunit rRNA (1,254 bp), the intergenic spacer (276 bp), and the 5S region (115 bp). The organization of the rRNA gene is 5′-LSU-ITS-SSU-IGS-5S-3′, which is reverse compared to the organization of most microsporidian rRNA regions. Phylogenetic analysis based on small subunit rRNA sequences showed that this isolate belongs to the genus Endoreticulatus, and is closely related to Glugoides intestinalis. Furthermore, both had a similar reverse arrangement of the rRNA gene. Our study provides another example of a microsporidian species with a novel organization of rRNA genes, demonstrating that the reverse arrangement is exhibited not only by the microsporidian genus Nosema but may also occur in a clade that contains the genera Endoreticulatus and Glugoides.