Production of rhodomycins inStreptomyces griseoruber 4620

The strainStreptomyces griseoruber 4620 produces, besides the anthracycline antibiotics beromycins, some other anthracyclines of the rhodomycin type. Twelve isolates exhibiting a higher antibiotic activity (up to 2.5×), as compared to the parent strain, were obtained after a spontaneous selection. The following species were isolated from the hydrolysate of mycelial extract: β-rhodomycinone, β-isorhodomycinone, α₂-rhodomycinone and 10-deoxy-β-rhodomycinone, which has not yet been described.     

TWO FORMS OF ALANINE AMINOTRANSFERASE IN RAT BRAIN DURING ONTOGENY

Abstract— Alanine aminotransferase activity in subcellular fractions of rat brains was investigated during ontogenic development. The activity rose from the prenatal period until adulthood, the highest increase being observed during the period of morphological metabolic and functional maturation of the brain. The rise of the total activity was due predominantly to a rise in the activity of the cytosblic enzyme; the activity of the mitochondrial enzyme did not change markedly during ontogeny. CI-ions and elevated temperature (55°C) inhibited the activity only of the mitochondrial enzyme. Raised temperature stimulated the activity of the cytosolic enzyme while CI-ions did not influence its activity. Our results indicate that 2 alanine aminotransferase isoenzlmes are already present in the rat brain in the prenatal period. It is assumed that the cytosolic enzyme is involved in the regulation of tissue glycol)sis and alanine formation, while the mitochondrial enzyme plays a role in the amino nitrogen transport between mitochondria and cytosol.     

Ultrastructural effects of 6-hydroxy-dopamine and 5, 6-dihydroxytryptamine on the central nervous system of fresh-water mussel, Anodonta cygnea L

Ultrastructural effects of 6-hydroxydopamine and 5, 6-dihydroxytryptamine treatments were investigated in the central nervous system of fresh-water mussel. Two days after the treatments, the following characteristic find-structural alterations could be observed in the neuropil of the ganglia: frequent occurrence of multilamellar bodies, lysosomatic structures and elongated tubular forms; shrinking of varicose axon profiles with an enchancement of the density of the axoplasm and clumping of its content; abnormal swelling of certain axons in the neuropil. This degenerative process was accompanied by an intense phagocytosis. The damages evoked by the employed "false transmitters" in the mussel ganglia were, in general, similar to those found in vertebrates. Statistical analysis of the vesicle population of ganglia suggests the intragranular uptake of 6-hydroxydopamine and 5, 6-dihydroxytryptamine and, in addition, the role of dense-core vesicles of different types in the storage of both serotonin and catecholamines. Perikarya composing the cortical layer of the ganglia were not affected by the "false transmitters". This shows that different parts of a mussel neuron are differently sensitive to 6-hydroxydopamine and 5, 6-dihydroxytryptamine.     

Growth inhibition of a MC-induced mouse sarcoma by TCGF (IL 2)-containing preparations

Summary Supernatants from Con A-stimulated rat spleen cell cultures containing T cell growth factor inhibited growth of a transplantable 3-methylcholanthrene-induced sarcoma in syngeneic mice. The tumour-inhibitory effects were dependent on the concentration of T cell growth factor and repeated injections of the supernatants.     

Hyperpolarization and intracellular acidification in Trichoderma viride as a response to illumination.

Using indirect methods based on uptake of [3H]tetraphenylphosphonium cation and [14C]benzoic acid by cells of the fungus Trichoderma viride we found that the illumination-induced transient hyperpolarization of the plasma membrane is followed immediately by a rapid temporary decrease in intracellular pH. Hyperpolarization and intracellular acidification were completely suppressed by 150 mM-KCl and by the K(+)-ionophore valinomycin. The light-induced acidification of the cytoplasm was not observed in the presence of the cytochrome respiratory chain inhibitors antimycin A and mucidin. Based on these results, we hypothesize that the hyperpolarization of the cells is the consequence of an efflux of K+ through a light-activated K(+)-channel in the plasma membrane. The loss of positive charge in the cytoplasm caused by this efflux of cations is counterbalanced by H+ originating from the light-activated mitochondrial respiratory chain.     

Comparative response ofPisum sativum nodulated with indigenous soilRhizobium populations and/or co-inoculated with aRhizobium leguminosarum strain

No significant differences in the acetylene-reducing activity and evolution of H₂ and CO₂ nodulated roots ofPisum sativum inoculated with soilRhizobium populations from two soils with different acidities (Ruzyně soil 7.6; Lukavec soil 4.9) were observed.Rhizobium population from Lukavec soil formed nodules, exhibiting a higher H₂ evolution. Co-inoculation with the Hup⁺ strain 128C30 (7×10⁷ cells per seedling) eliminated, to some extent, the effect of soil populations on physiological activity. Translated by Č. Novotny