Length of human constitutive heterochromatin in relation to chromosomal contraction

Summary Linear measurement of blocks of constitutive heterochromatin and the euchromatin portion 1q-h in three members of a family was used to study the dependence of the size of C blocks on the degree of chromosomal contraction. The results demonstrate that the size of heterochromatin portions decrease regularly with an increases of the degree of euchromatin contraction. The dependence was found to be linear, except for mitoses with an extremely high or low degree of contraction. The finding was used for the development of a new method of evaluation of constitutive heterochromatin.     

Identification ofStaphylococcus andMicrococcus species with the STAPHYtest system

A collection of 216 well-characterized strains ofStaphylococcus, Micrococcus andStomatococcus was examined by a commercially available STAPHYtest system (Lachema, Brno, Czechoslovakia). The results of STAPHYtest agreed with those of conventional tests. The STAPHYtest permitted a clear-cut separation ofStaphylococcus fromMicrococcus andStomatococcus strains and correctly identified 104 of 145 (72%)Staphylococcus strains after 24 h of incubation. However, it allowed the identification only of 19 of 29 validly publishedStaphylococcus species. The STAPHYtest proved to be a simple and rapid system for the separation of staphylococci from micrococci and for the identification of most frequent clinically significant staphylococci.     

Positive and Negative Effects of Tacrine (Tetrahydroaminoacridine) and Methoxytacrine on the Metabolism of Acetylcholine in Brain Cortical Prisms Incubated Under "Resting"Conditions

The effects of tacrine (1,2,3,4-tetrahydro-9-aminoacridine) and 7-methoxytacrine on the metabolism of acetylcholine were investigated in experiments on prisms of rat cerebral cortex incubated in vitro in low-potassium (3 mmol/L K+) media; cholinesterases were inactivated by paraoxon to avoid any action of tacrine and methoxytacrine via their inhibition. Under "resting" conditions, tacrine and methoxytacrine increased the synthesis of unlabeled acetylcholine in the prisms; at the same time, they inhibited the uptake of [14C]choline from the medium and the synthesis of [14C]acetylcholine. The concentration of free choline was not increased by tacrine or methoxytacrine in either the tissue or the medium. The contradiction between the increased synthesis of unlabeled and the diminished synthesis of labeled acetylcholine indicates that the utilization of intracellular choline (which is presumably mobilized from intracellular choline esters) for the synthesis of acetylcholine is increased by tacrine and methoxytacrine. This conclusion is supported by the observation that the inhibition of acetylcholine synthesis during incubation with hemicholinium-3 (an inhibitor of choline transport into cholinergic nerve terminals) was overcome when tacrine was present simultaneously with hemicholinium-3. When the prisms were preincubated with [14C]choline and incubated with tacrine or methoxytacrine only after this, the amount of [14C]acetylcholine recovered in the tissue plus the medium was higher at the end of incubation with tacrine or methoxytacrine than without them, again suggesting that the drugs were able to increase the utilization of intracellular [14C]choline or its esters for acetylcholine synthesis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Changes of intraocular pressure in patients with open-angle glaucoma in relation to the passage of atmospheric fronts and environmental contamination

Effects of atmospheric frontal passages on intraocular pressure (IOP) in patients with open-angle glaucoma are statistically investigated to show the meteorotropism of this disease. Changes in IOP caused by frontal passages are evident; the response is not identical in all the patients near the day of the passage of a warm front, while on the third day following the passage of the front a well pronounced drop in IOP occurs. Anomalous increases of IOP over several months' duration occurred in the years 1986–7. This finding is explained in relation to the hypothesis of environmental contamination in Central Europe by radioactive cesium nuclides due to the Chernobyl accident.     

Use of whey for production of exocellular polysaccharide by a mutant strain ofXanthomonas campestris

Growth and kinetics of the production of exocellular polysaccharide was studied in a mutant strain ofXanthomonas campestris lac ⁺ during cultivation in a submerged culture in a medium containing whey. The maximum production of the polymer was observed at the initial stage of the stationary growth phase of the culture. The mean production yield was about 1.4%. The results were comparable with those obtained during cultivation on a lactose medium. Translated by Č. Novotny     

Isolation and sequence analysis of the genomic DNA fragment encoding an aspartic proteinase inhibitor homologue from potato (Solanum tuberosum L.)

A genomic DNA clone encoding an aspartic proteinase inhibitor of potato was isolated from a lambda EMBL3 phage library using the aspartic proteinase inhibitor cDNA as a hybridization probe. The gene has all characteristic sequences normally found in eucaryotic genes. Typical CAAT and TATA box sequences were found in the 5-upstream region. In this part are also two putative regulatory AGGA box sequences located. In the genomic sequence there are no intron sequences interrupting the coding region. An open reading frame of the gene encodes a precursor protein of 217 amino acids which shows high percent identity with the aspartic proteinase inhibitor cDNA.