Apoptosis and nutrition: Involvement of amino acid transport system in repression of hybridoma cell death

Mouse hybridoma cells cultured on the verge of starvation-induced apoptosis, i.e. in a medium diluted with saline, proved to serve as a sensitive screening system for apoptosis-suppressing activity of nutrient medium components. Conventional amino acid mixtures were found to suppress the starvation-induced apoptosis, whereas a vitamin mixture was ineffective. (Frank F (1995) Biotechnol. Bioeng. 45: 86–90). Recent experiments showed that suppression of apoptosis, and concurrent resumption of growth, could be achieved by addition of single substances at millimolar concentrations. The set of active substances included certain coded L-amino acids (glycine, alanine, serine, threonine, proline, asparagine, glutamine, histidine), non-coded amino acids (-alanine, taurine, 4-aminobutyric acid), and a non-metabolizable analogue (2-aminoisobutyric acid). This finding shows that some amino acids do not act solely as nutrients, but also as specific signal molecules. The specificity of the effect points to the involvement of adaptively regulated amino acid transport systems A and N in maintaining the balance between triggering and suppression of starvation-induced apoptosis.     

Palaeoecological and phytosociological reconstruction of precultural vegetation in the Bílý Kříž area,the Moravskoslezské Beskydy Mts,Slovak Republic

A combined palynological and phytosociological methodological approach was used in the reconstruction of precultural forest vegetation in a small model area of Bílý Kí-Janík in the Moravskoslezské Beskydy mountains (northwest Slovakia). Two pollen diagrams show the predominance of Fagus sylvatica, Abies alba and Picea abies in past natural mixed forests. The present-day occurrence and distribution of forest herbs allow the differentiation of five past vegetation types with above mentioned forest climax trees covering the area before the beginning of human interference. A map of reconstructed natural vegetation is presented which can be used for revitalization of present secondary spruce plantations, heavily affected by air pollution.     

On-line water removal during enzymatic asymmetric esterification in organic media

Summary Enantioselective esterification of 2-bromopropionic acid with n-butanol using Candida cylindracea lipase was carried out in n-pentane at various initial water contents. Reaction rate as well as enantioselectivity decreased at high water content. A heteroazeotropic distillation method was applicable to remove the excess water continuously and to work at the optimum reaction conditions.     

A new mutation protocol for obtaining auxotrophic mutants of the yeastPhaffia rhodozyma

Summary A new mutation strategy, which involves -irradiation of cells followed by a selective enzymatic enrichment step, was worked out to obtain auxotrophic mutants from the astaxanthin-producing yeast P. rhodozyma. Under the optimized conditions described, different mutants suitable for strain improvement were isolated.     

Solid-state fermentation of sugarcane bagasse with Flammulina velutipes and Trametes versicolor

The mushroom Flammulina velutipes and the white-rot fungus Trametes versicolor were cultivated separately on sugarcane bagasse for 40 days. Trametes versicolor produced laccase and manganese-peroxidase activities, showing a simultaneous degradation of lignin and holocellulose. However, only phenoloxidase activity was found with Flammulina velutipes. A preferential degradation of lignin was detected in F. velutipes, which exhibited a greater reduction in the ratio of weight loss to lignin loss than T. versicolor. A decrease in the syringyl/guaiacyl ratio observed with both fungi indicated the preferential degradation of non-condensed (syringyl-type) lignin units. An increase in the relative abundance of aromatic carboxylic acids suggested that the oxidative transformation of lignin unit side-chains was occurring. This was more noticeable with Flammulina velutipes than with T. versicolor.     

Superoxide dismutase mimetic activity of a cyclic tetrameric Schiff base N-coordinated Cu(II) complex

A pulse radiolytic study using the cyclic tetrameric Schiff base N-coordinated copper complex Cu(TAAB)²⁺ has been performed. The reaction of the Cu(TAAB)²⁺ complex with superoxide revealed pseudo first-order characteristics with the rate constant of k ₂ = (2.9 ± 0.5) × 10⁸ mol^–1 s^–1 dm³. The complex survive presence of competing serum albumin in physiological concentrations. The complex stability constant K = 1.15 × 10¹⁸ (log K = 18.06) is two orders of magnitude higher than that of Cu(II)-serum albumin (log K = 16.2). Transient changes of the stability during the oxidation/reduction process and in the presence of 600 /mol l^–1 albumin did not affect significantly either the electronic absorption of the complex or its catalytic activity.     

Postjunctional Origin of the indirect-like sympathomimetic effect of metanephrine and normetanephrine on blood pressure

The effects of metanephrine and normetanephrine have been compared with those from equiactive doses of the origin compounds, adrenaline and noradrenaline, on the pressor responses in rat, in order to determine whether their effects are owed, at least partially, to a releasing presynaptic action of the catecholamines in normal animals as well as those pretreated with reserpine, guanethidine and 6-OH-dopamine. Their effects have likewise been studied in isolated perfused renal arteries both in normal and reserpinized rats. None of the adrenolytic agent used were able either to reduce the duration of the hypertensive response or to accelerate tachyphylaxis. Identical results were obtained in renal artery preparations. It is thus concluded that the catecholamines stored in presynaptic endings are not involved in the observed phenomena and it is suggested that they might depend on the high doses required to produce effects equiactive to those of the origin substances.     

Immobilization of the cellulolytic fungus Trichoderma reesei on the polymeric sorbent - Sorfix

Summary The immobilization of T. reesei mycelium on activated polymeric sorbent was investigated with respect to the intended flow-trough cellulase production. The retention of extracellular production of cellulolytic enzymes was monitored in a packed-column recycle reactor. Some factors affecting cellulase elution pattern are described.     

A large transmissible plasmid is required for crystal toxin production in Bacillus thuringiensis variety israelensis

Bacillus thuringiensis var. israelensis (BTI), serotype 14, which produces parasporal crystals toxic to certain dipteran larvae, was analyzed by agarose gel electrophoresis and found to contain a complex plasmid array. Eight plasmids were detected, with approximate sizes of 3.3, 4.2, 4.9, 10.6, 68, 75, 105, and 135 MDa, as well as a plasmidlike linear DNA element of ~10 MDa. Partially cured mutants of BTI implicated the 75-MDa plasmid in crystal production. Fifteen independently isolated acrystalliferous (Cry^?) mutants were found to lack this plasmid. In plasmid transfer experiments, several of the BTI plasmids transferred into a plasmid-free, Cry^? BTI recipient, but only transfer of the 75-MDa plasmid converted the recipient to crystal toxin production. The presence or absence of mosquito-toxic activity in all Cry⁺ and Cry^? variants of BTI was confirmed by bioassay of sporulated cultures against larvae of Aedes aegypti. Southern blot analyses revealed that in one unusual Cry⁺ variant in which no 75-MDa plasmid band was detectable, plasmid sequences were still present, possibly integrated into the chromosome. The 75-MDa plasmid could also apparently recombine with the 68-MDa plasmid, to which it was partially homologous.     

Clinical, enzymological and histological changes in chronic diffuse liver diseases following (+)-cyanidanol-3 (Catergen) treatment

The effect of (+)-cyanidanol-3 (Catergen) monotherapy was examined in 18 patients with alcoholic liver disease and in 12 patients with chronic active hepatitis. During the administration of the drug the majority of complaints diminished or ceased in both groups. In patients with alcoholic liver disease bromsulphalein retention and gamma glutamyl transferase levels decreased, in chronic active hepatitis serum glutaminic pyruvic acid transaminase (SGPT) and alkaline phosphatase levels increased, pseudocholinesterase level decreased. The histological abnormalities of alcoholic liver injury improved in the majority of cases, on the other hand, it was deteriorated in two third of the cases with chronic active hepatitis. In two cases the histological recovery of acute alcoholic hepatitis was observed. On the basis of this results we conclude that Catergen has an excellent therapeutic effect in alcoholic liver injury while in chronic active liver diseases it can be applied only as a part of combined therapy.