Postnatal changes of some enzymatic activities of energy supplying metabolism in the cortex, inner and outer medulla of the rat kidney

1. In rat kidney cortex, outer and inner medulla the development of activities of seven enzymes was investigated during postnatal ontogeny (10, 20, 30, 60 and 90 days of age). The enzymes were selected in such a manner, as to characterize most of the main metabolic pathways of energy supplying metabolism: hexokinase (glucose phosphorylation, HK), glycerol-3-phosphate dehydrogenase (glycerolphosphate metabolism or shunt, GPDH), triose phosphate dehydrogenase (glycolytic carbohydrate breakdown, TPDH), lactate dehydrogenase (lactate metabolism, LDH), citrate synthase (tricarboxylic acid cycle, aerobic metabolism, CS), malate NAD dehydrogenase (tricarboxylic acid cycle, intra-extra mitochondrial hydrogen transport, MDH) and 3-hydroxyacyl-CoA-dehydrogenase (fatty acid catabolism, HOADH). 2. The renal cortex already differs metabolically from the medullar structures on the 10th day of life. It displays a high activity of aerobic breakdown of both fatty acids and carbohydrates. Its metabolic capacity further increases up to the 30th day of life. 3. The outer medullar structure is not grossly different from the inner medulla on the 10th day of life. Further it differentiates into a highly aerobic tissue mainly able to utilize carbohydrates. It can, however, to some extent, also utilize fatty acids aerobically and produce lactate from carbohydrates anaerobically. 4. The inner medullar structure is best equipped to utilize carbohydrates by anaerobic glycolysis, forming lactate. This feature is already pronounced on the 10th day of life, its capacity increases to some extent during postnatal development, being highest between the 10th and the 60th day of life.     

Comparative mineral and hormonal analyses of wild type and TLS somaclonal variant derived from oil palm (Elaeis guineensis Jacq. var. tenera) tissue culture

Comparative mineral and hormonal analyses were made on tissue culture derived truncated leaf syndrome and wild type oil palm seedlings. Mineral analysis confirmed that Boron, Zinc and chlorophyll levels were significantly lower in truncated leaf syndrome leaves than those of wild type. Hormonal analysis also revealed various cytokinin derivatives such as trans-zeatin, trans-zeatin riboside, trans-zeatin O-glucoside and trans-zeatin riboside 5??mono phosphate were significantly higher in truncated leaf syndrome leaves compared to wild type leaves. Brassinolide level was also significantly higher in truncated leaf syndrome leaves than those of the wild type. These observations suggest that the truncated leaf syndrome abnormality could be associated to high cytokinin and brassinosteroid production which affects the uptake of Boron and Zinc.     

Stability of Lanatoside C content in thein vitro propagatedDigitalis lanata clones

In vitro culture was established from shoot tips ofDigitalis lanata cotyledonous plants. The propagated plant material was rooted, transplanted into soil and grown under field conditions. Lanatoside C content was determined in a total of 20 clones and statistically evaluated by means of variance analysis of unequal-sized samples.In vitro clonal propagation ofD. lanata was found not to affect lanatoside C content. Drug level was dependent on a plant genotype.     

Conversion of disaccharides to 3-ketodisaccharides by nongrowing and immobilized cells ofAgrobacterium tumefaciens

High-performance liquid chromatography was used to estimate 3-ketolactose and 3-ketosucrose in cultures of agrobacteria. The activities of enzymes that convert the disaccharide substrate were evaluated during batch cultivation ofAgrobacterium tumefaciens on sucrose, maltose, and lactose. The highest activity of glucoside 3-dehydrogenase and a slight activity of disaccharide-hydrolyzing enzymes were found in cells grown on lactose. Nongrowing cells converted lactose to 3-ketolactose faster than immobilized cells did. Immobilization of cells into polysaccharide gels did not stabilize the activity of glucoside 3-dehydrogenase. Glutaraldehyde cross-linking of the cell content led to an inactivation of the respiratory chain but Fe³⁺ could be used as an electron acceptor. Cells treated with glutaraldehyde converted lactose faster than nongrowing ones but the activity of glucoside 3-dehydrogenase was not stable.     

abetd-Xylose metabolism in Aureobasidium pullulans: effects of aeration and vitamins

Summary The yeast-like organism Aureobasidium pullulans efficiently converted abetd-xylose to cell mass (Y _X/S=0.45 g·g^–1) with negligible production of polyols (Y _P/S=0.003 g·g^–1) under aerobic conditions. A. pullulans grown semiaerobically exhibited different fermentation capacities in seven basal (vitaminless) medium and medium containing a mixture of seven vitamins. It was found that under semiaerobic conditions a mixture of vitamins significantly enhanced production of ethanol from abetd-xylose, resulting in a 15-fold higher yield coefficient of ethanol (Y _E/S=0.22 g·g^–1) as compared to that achieved in vitaminless medium. This increase in ethanol production was accomplished at the expense of cell mass. A. pullulans produced extremely low amounts of polyols throughout all aerobic and semiaerobic experiments. A. pullulans displayed strictly NADPH-linked xylose reductase and NAD⁺-linked xylitol dehydrogenase activities.     

Sterol composition of a δ5,7-sterol-rich strain ofSaccharomyces cerevisiae during batch growth

Sterol composition was examined during batch growth on complex media containing ethanol, molasses or glucose as the carbon source. The molasses-grown cells exhibited a balanced sterol composition throughout growth, maintaining the proportion of ergosterol to 24:28-dehydroergosterol equal to 1.4. The negative effect of glucose on sterol synthesis manifested itself by decreasing the accumulation of 24:28-dehydroergosterol and total sterols but not of ergosterol. Using ethanol as the sole carbon source, a large amount of 24:28-dehydroergosterol accumulated, partly at the expense of other sterols. The gradual addition of nitrogen source during growth significantly decreased the accumulation of ergosterol, 24:28-dehydroergosterol and of total sterols. A general scheme of regulation of sterol synthesis in baker's yeast is presented.     

Cytogenetic analysis of peripheral blood lymphocytes in glass workers occupationally exposed to mineral oils

Chromosome aberration tests were carried out in a group of 31 pressed glass makers operating an automatic line of press-and-blow machines known to release mineral oil mists containing relatively high concentrations of the mutagenic chemicals belonging to a class of polycyclic aromatic hydrocarbons (PAH). The workers were exposed to the mineral oil aerosol levels that did not exceed the Czechoslovak maximum allowable concentration limit of 5 mg . m-1 of air. The tests revealed that the frequency of aberrant cells (% AB.C.) and the value of breaks per cell (B/C) ratio found in mineral oil-exposed workers were increased significantly, accounting for 4.65 +/- 0.29% AB.C. (0.0532 B/C) vs. 1.13 +/- 0.19% AB.C. (0.0113 B/C) seen in matching controls. Also, a higher rate of dicentrics, reciprocal translocations and cells with pulverization was observed in this group of glass workers. These finding are considered as evidence suggesting that these workers might experience an increased risk of genetic injury due to exposure to mineral oil mists.     

Cytogenetic effect of plant tissue culture medium with certain growth substances onAllium sativum L. meristem root tip cells

The effect of plant tissue culture medium with different concentrations and combinations of growth regulators (kinetin, indol-3-ylacetic acid, 2,4-dichlorophenoxyacetic acid) was evaluated on mitosis ofAllium sativum meristem root tip cells. Different combinations of growth regulators at low concentrations had no effect on induction of mitotic aberrations or inhibition of mitotic activity. Inhibition of mitotic activity, a tendency to chromosome stickiness and clumping and a slight increase in the frequency of mitotic aberrations were observed at higher concentrations. It may be proposed that plant tissue culture media have no direct effect on induction of mitotic aberrations in plant tissue culturesin vitro.