Some aspects of sucrose transport and utilization in latex producing bark ofHevea brasiliensis Muel. Arg

The radiotracer technique is described for transport and metabolic studies in latex producing bark. This technique provided further evidence that carbohydrates are supplied to latex vessels as sucrose and that sucrose is readily used for rubber synthesis. Bark treatment with ethylene resulting in latex flow stimulation is shown to activate within a few hours sucrose and water transport into the latex vessels. The available knowledge suggests an implication of an energy-dependent process of proton excretion which could explain the earlier observed ethylene induced alkalization of latex cytosol enhancing invertase and sucrose utilization. An increase of tapping intensity decreases the level of latex sucrose and changes its distribution pattern in drained bark. There is a clonal difference in the early response to exploitation. Bark excision by conventional tapping inhibits downward sucrose translocation, the inhibition being proportional to the surface of consumed bark above the tapping cut. Seasonal variation in the level of latex sucrose is related to variations in sunshine duration and sucrose concentration rises during the process of refoliation. The results stress the importance of sucrose supply to latex vessels for latex producing potentialities and indicate an association of low sucrose availability in latex vessels with premature latex vessel degeneration and bark dryness.     

DasJuncetum alpino-articulati blysmetosum compressi in den nordwestslowakischen Karpaten

Kopecký K. (1987):Juncetum alpino-articulati blysmetosum compressi in the North-Western Slovak Carpathian Mountains.—Folia Geobot. Phytotax., Praha, 22: 171–178.—The newly described plant community of the associationJuncetum alpino-articulati subassblysmetosum compressi colonizes sandy alluvial deposits in the subriparian tier (at and below annual mean watermark) on the banks of the upper Biela Orava river in the north-western Slovakian Carpathian Mts. at the altitudes of 800 to 850 m. The high content of CaCO₃ leached from the subsoil, is reflected in the species composition of the community which belongs to the orderTofieldietalia of the classScheuchzerio-Caricetea fuscae.     

Autoradiographic detection of uptake of bacterial3H-DNA label by barley seeds and isolated barley embryos

Barley seeds and extirpated embryos were cultivated in³H-DNA fromBacillus subtilis. Control group of embryos was cultivated in³H-thymidine. Uptake of the label from³H-DNA was observed after both methods of application, to halves of seeds and to embryos, and the label was localized almost exclusively in some of the nuclei of meristematic cells.     

Microbial changes in clover rhizosphere after foliar and soil application of cobalt

Application of cobalt(II) nitrate to the leaves of red clover (Trifolium pratense L.) resulted in a pronounced increase of dry weight and the number of root nodules. Counts of bacteria in the rhizosphere, content of ammonia and production of carbon dioxide m rhizosphere soil were also higher, whereas the content of nitrates decreased Differences m the counts of bacteria, aotmomycetes, Azotobaoter, anaerobic bacteria and cellulose decomposing bacteria m the rhizosphere of control and treated plants were not directly related to the way of application of cobalt. GeneraPenicillium, Fusarium andTrichoderma predominated among fungi. The relative occurrence of pemcillia was higher after the application of cobalt, the incidence of fusaria was lower. The effects of foliar and soil application of cobalt on rhizosphere microflora were not identical.     

Superovulation in cattle: Effect of goat anti-PMSG serum

Sixteen heifers were superovulated using 5 000 i.u. PMSG on days 9 to 11 of the oestrous cycle (day 1 of the experiment) followed by two injections of 500 mug Estrumate 48 and 54 hours later. Eight of them were injected with goat anti-PMSG serum 5 hours after the first signs of oestrus were observed. Compared with the control group, the treatment with anti-PMSG serum resulted in a shorter heat period (25.8 vs. 51.3 hours), a higher mean number of ovulations (22.1 vs. 18.0) and a lower number of follicles over 10 mm in diameter (4.1 vs. 22.3). The mean numbers of eggs recovered in the experimental and control groups were 17.8 and 6.9, of which 70.2 and 42.0 per cent, respectively, were viable embryos. The concentrations of progesterone and 17-beta oestradiol in the blood plasma showed no significant differences between the experimental and control animals. A higher oestradiol in the control group on day 9 of the experiment was in keeping with the histological picture of the target organs and with a significantly higher number of follicles at slaughter on days 12 to 14 of the experiment.     

Über die Verbreitung und Variabilität desHordeetum murini in der westslowakei

Der Autor bewertete und emendierte die AssoziationHordeetum murini Libbert 1932. Er analysiert und klassifiziert die Variabilität der emendierten Assoziation, alsoHordeetum murini Libbert 1932 em.Eliá? 1979 auf dem Gebiet der Westslowakei. Er unterschied und beschrieb einige neue Syntaxa. Die Arbeit enthält phytozönologische Aufnahmen aus der Westslowakei und eine synthetische Tabelle.     

Electron-impact mass spectrometry of methyl O-methylglucopyranosiduranamides

6-O-Acetyl-2,4-diazido-3-O-benzyl-2,4-dideoxy-β-D-glucopyranosyl chloride and 2,6-diazido-3,4-di-O-benzyl-2,6-dideoxy-β-D-glucopyranosyl chloride are two valuable building units suitable for the synthesis of α-linked disaccharides containing 2,4-diamino-2,4-dideoxy- or 2,6-diamino-2,6-dideoxy-D-glucose as nonreducing moieties. The glycoside synthesis is accomplished stereoselectively under mild conditions in the presence of silver perchlorate. The α-(1→3)-linked disaccharides 2,4-diacetamido-2,4-dideoxy-3-O-(2,4-diacetamido-2,4-dideoxy-α-D-glucopyranosyl)-D-glucopyranose and 2-acetamido-2-deoxy-3-O-(2,6-diacetamido-2,6-dideoxy-α-D-glucopyranosyl)-D-glucopyranose have been prepared.     

Experimental toxicology in silico

A review on applicability of in silico methods for toxicity testing by calculation for regulatory purposes, their survey and background of QSAR (Quantitative Structure-Activity Relationships) analysis are presented.     

Apoptosis and expression of Bcl-2 in human endometrium in natural and artificial cycles

Apoptosis plays a significant role in differentiation of many organs and helps to maintain homeostasis. The occurrence of apoptosis (using the apoptotic index) and expression of regulation protein Bcl-2 in the human endometrium was evaluated within the secretory phase of both the natural cycle, and an artificial one. Oral hormonal substitution used in this design induced similar, but more marked dynamic changes in Bcl-2 expression in the mid-secretory endometrium as were observed in the natural cycle, primarily in the surface and glandular epithelium of the endometrium. The apoptosis revealed similar a trend, but not significantly different.