The occurrence of Cryptocoryne and Lagenandra (Araceae) on Sri Lanka

Depending on the species, Cryptocoryne plants grow in different biotopes, viz. spring, river, dark forest, and tree-savanna. The species of Lagenandra are exclusively found in river biotopes. The chromosome numbers found in this study corroborate the numbers previously recorded. Some variation in respect to the morphology of the inflorescence of C. wendtii de Wit and L. ovata (L.) Thwaites is described. A map presenting the distribution of the of Cryptocoryne with their chromosome numbers is included.
The existing populations of Cryptocoryne on Sri Lanka should be protected from further exploitation by plant collectors.     

HLA-JY328: Mapping studies and expression of a polymorphic HLA class I gene

The JY328 clone was identified in a human genomic library using cDNA corresponding to mRNA for HLA-B7 as a probe. The L/328 cell line was established by cotransformation of mouse Ltk^– cells with the herpes thymidine kinase gene and clone JY328. On Northern blots, RNA from,L/328 strongly hybridized to an HLA class I probe, and an antigen was recognized by an anti-HLA class I framework antibody on the cell surface. A DNA probe corresponding to a segment of intron 7 was developed by comparing the nucleotide sequence of clone JY328 with that of other HLA class I-type genes. Using the radiolabeled probe to screen Southern blots of DNA from families with siblings exhibiting intra-HLA recombinations, a restriction fragment length polymorphism was revealed —a 1.4 kb BstE II band not present in all individuals. A corresponding fragment was apparent in the base sequence of clone JY328. The occurrence of this band on Southern blots established that JY328 maps distinct from and centromeric to the HLA-C locus and near to the HLA-B locus. Antibody absorption studies and cytotoxicity tests indicated that the JY328 gene product was not an HLA-B antigen but that it did specifically absorb CW7-specific antibody. In sum, these results suggest a novel, polymorphic HLA class I gene which expresses a product serologically similar to HLA-Cw7 but which does not map within the corresponding locus.     

Epoxidation of alkenes by alkene-grown Xanthobacter spp.

Summary Newly isolated Xanthobacter spp. were able to grow on the gaseous alkenes like ethene, propene, 1-butene and 1,3-butadiene. Resting-cell suspensions of propene-, 1-butene- or 1,3-butadiene-grown Xanthobacter Py10 accumulated 1,2-epoxyethane from ethene. Ethene-grown Xanthobacter Py10 did not produce any 1,2-epoxyalkane from the alkenes tested. Furthermore, propenegrown Xanthobacter Py2 accumulated 2,3-epoxybutane from trans-butene and cis-butene but did not form epoxides from other substrates tested.     

IMP production and energy metabolism during exercise in rats in relation to age.

IMP production in and force exerted by rat quadriceps muscle in situ during various types of exercise were examined in relation to age. During continuous isometric exercise with constant stimulation time, the amount of IMP was linearly and inversely related to the age of the animals; a higher IMP concentration was found in intermittent isometric and dynamic exercise. No relationship was found between the total AMP deaminase activity and age. Exercise influenced neither the total activity nor the activity in the soluble fraction. From the results it is concluded that: the IMP concentration is linearly related to the free intracellular ATP4-/ADP3- ratio and the free AMP2- concentration; older animals are better able to maintain a high intramuscular ATP4-/ADP3- ratio and a low AMP2- concentration; IMP is produced in particular under conditions when the muscle has to work under extreme stress. IMP possibly exerts a feed-back control on the contraction system.     

Changes in erythropoiesis due to radiation or chemotherapy as studied by flow cytometric determination of peripheral blood reticulocytes

Flow cytometric determination of time dependent changes of numbers of reticulocytes in peripheral blood were investigated as a parameter for changes in erythropoiesis induced by radiation- or chemotherapy. Rats irradiated or treated with drugs (such as e.g. cyclophosphamide 100 mg/kg, vincristin 0.2 mg/kg, or mitomycin C 1.0 mg/kg) showed clear changes in erythropoietic activity. Reticulocyte numbers decreased rapidly until day 3-4 after treatment; this period was followed by a gradual increase and normal control values were seen at day 8-11. Radiation effects of doses as low 0.5 Gy could be detected in such a way. Similar studies were performed with patients with ovarian tumors treated with cis-platinum, a drug that may cause non-immune haemolysis. During prolonged treatment some patients showed increasing numbers of reticulocytes, measured at the first day of each hospitalization period, whereas leucocyte and platelet counts stayed more or less constant. Increasing numbers of reticulocytes generally indicates stimulation of erythropoietic activity of the bone marrow (due to increased blood loss); in this study increasing numbers often preceeded a decrease in hemoglobin values later on. Flow cytometric analysis of reticulocytes is therefore a potentially useful tool to detect changes in erythropoiesis, and considered more sensitive for the early recognition of patients that develop anemia, than hemoglobin measurements only.     

Maternal 3:1 disjunction in a tranlocation 9/17

Summary An isochromosome of 15(q12) was found in a mentally retarded patient with behaviour disorders which included hyperactivity, short attention span, aggression, and autistic behaviour. There were only minor physical anomalies; he did not have the Prader-Willi syndrome.     

Stress by forced swimming in the rat: effects of mianserin and moclobemide on GABAergic-monoaminergic systems in the brain

The stress caused by forced swimming in male rats provoked a decrease in brain NA levels without changes in DA and 5-HT content, MAO and GABAergic activity. Acute or chronic treatment with mianserin did not modify the decrease in NA concentration in the brain of stressed rats. Acute treatment with moclobemide (IMAO) did not modify the decrease in NA content caused by stress; chronic treatment blocked the decrease in NA content in stressed rats.     

Simple computer method for evaluation of lateral diffusion coefficients from fluorescence photobleaching recovery kinetics.

A method is presented for the analysis of fluorescence photobleaching recovery curves. Based on the simplified kinetic expression of Yguerabide, J., J.A. Schmidt, and E.E. Yguerabide (1982, Biophys. J., 40:69-75), a linearization procedure is described that permits unequivocal determination of all diffusion parameters. The presence of additional membrane flow or multiple diffusion coefficients can easily be detected by this method, and simple corrections for the presence of these alternative recovery processes can be made by the use of a regular mini-computer. The validity of the method is tested on simulated recovery curves, varying the contribution of flow, multiple diffusion coefficients, and statistical noise due to counting error.