Hybrids between tobacco crown gall cells and normal somatic cells of Atropa belladonna

Protoplast fusion of Nicotiana tabacum (B6S3) crown gall cells and Atropa belladonna leaf mesophyll cells was carried out. Hybrids were selected for their capacity to grow on hormone-free media and to green in light. Shoots incapable of rhizogenesis were regenerated on the same media and grafted onto normal plants of different species. 57 hybrid cell lines differing in their genetic constitution were produced. Analysis of hybrid lines involved the determination of the lysopine dehydrogenase (LpDH) activity and the molecular forms of esterase and amylase, a restriction analysis of chloroplast DNA and a cytogenetic study.Abbreviations LS-H Linsmaier and Skoog (1965) hormone-free medium - LpDH lysopine dehydrogenase     

Volume-dependent regulation of ion transport and membrane phosphorylation in human and rat erythrocytes

Summary Osmotic swelling of human and rat erythrocytes does not induce regulatory volume decrease. Regulatory volume increase was observed in shrunken erythrocytes of rats only. This reaction was blocked by the inhibitors of Na⁺/H⁺ exchange. Cytoplasmic acidification in erythrocytes of both species increases the amiloride-inhibited component of²²Na influx by five- to eight-fold. Both the osmotic and isosmotic shrinkage of rat erythrocytes results in the 10- to 30-fold increase of amiloride-inhibited²²Na influx and a two-fold increase of furosemide-inhibited⁸⁶Rb influx. We failed to indicate any significant changes of these ion transport systems in shrunken human erythrocytes. The shrinking of quin 2-loaded human and rat erythrocytes results in the two- to threefold increase of the rate of⁴⁵Ca influx, which is completely blocked by amiloride. The dependence of volume-induced²²Na influx in rat erythrocytes and⁴⁵Ca influx in human erythrocytes on amiloride concentration does not differ. The rate of⁴⁵Ca influx in resealed ghosts was reduced by one order of magnitude when intravesicular potassium and sodium were replaced by choline. It is assumed that the erythrocyte shrinkage increases the rate of a nonselective Ca _o ²⁺ (Na _i ⁺ , K _i ⁺ ) exchange. Erythrocyte shrinking does not induce significant phosphorylation of membrane protein but increases the³²P incorporation in diphosphoinositides. The effect of shrinkage on the³²P labeling of phosphoinositides is diminished after addition of amiloride. It is assumed that volume-induced phosphoinositide response plays an essential role in the mechanism of the activation of transmembrane ion movements.     

Metabolic activities in germinated ancient lotus seeds

Seeds of Taizi lotus (Nelumbo nucifera Gaertn cv. Taizi) wereunearthed in a western suburb of Beijing in 1984, and determinedto be 58070-years-old by radiocarbon dating. Pretreatment withconcentrated sulphuric acid for 6 h promoted 75% of the seedstested to germinate. Over 3 weeks of incubation after the additionof water, storage starch, total soluble sugar and globulin inthe cotyledons decreased whereas albumin and soluble -aminonitrogen increased. These changes in cotyledonary componentswere similar to the changes seen in four present-day Indianlotus varieties, although the content of reducing sugar in Taizilotus was significantly lower. The polypeptide compositionsin extracts from the cotyledons and embryonic axis of Taiziseeds, as analysed by SDS-PAGE, were similar to those of present-dayJiangxi seeds. Taizi lotus also showed the ability to incorporateradioactive leucine into the trichloroacetic acid (TCA)-insolublefraction of a cotyledonary extract during the 24 h post-imbibitionperiod. The incorporation was inhibited when seeds of Taizilotus were allowed to rehydrate for 24 h in the presence of-amanitin or cycloheximide. Key words: Ancient lotus, Nelumbo nucifera, protein synthesis, seed germination, seed viability     

Production of (R)-1-phenylethanol through enantioselective oxidation of (S)-isomer from their racemic mixture by Pachysolen tannophilus IFO 1007

Summary Stereoselective oxidation of (S)-isomer of rac-1-phenylethanol (1-PA) by the yeast Pachysolen tannophilus IFO 1007 immobilized into calcium-alginate gels was investigated to produce (R)-isomer. Continuous production of (R)-isomer was accomplished for more than 80 h with an enantiomeric excess of > 90% using a bioreactor of a fluidized-bed type.     

THE LASER TOMOGRAPHICAL METHOD USINGMINIMUM OF PROJECTION FOR BIOLOGICAL OBJECT STRUCTURE STUDY

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Brain ATP Depletion Induced by Acute Ammonia Intoxication in Rats Is Mediated by Activation of the NMDA Receptor and Na+, K+-ATPase

Abstract: Injection of large doses of ammonia into rats leads to depletion of brain ATP. However, the molecular mechanism leading to ATP depletion is not clear. The aim of the present work was to assess whether ammonium-induced depletion of ATP is mediated by activation of the NMDA receptor. It is shown that injection of MK-801, an antagonist of the NMDA receptor, prevented ammonia-induced ATP depletion but did not prevent changes in glutamine, glutamate, glycogen, glucose, and ketone bodies. Ammonia injection increased Na⁺,K⁺-ATPase activity by 76%. This increase was also prevented by previous injection of MK-801. The molecular mechanism leading to activation of the ATPase was further studied. Na⁺,K⁺-ATPase activity in samples from ammonia-injected rats was normalized by "in vitro" incubation with phorbol 12-myristate 13-acetate, an activator of protein kinase C. The results obtained suggest that ammonia-induced ATP depletion is mediated by activation of the NMDA receptor, which results in decreased protein kinase C-mediated phosphorylation of Na⁺,K⁺-ATPase and, therefore, increased activity of the ATPase and increased consumption of ATP.     

Organosoluble enzyme-polymer complexes: A novel type of biocatalyst for nonaqueous media

Summary A novel type of organosoluble biocatalyst, representing a non-covalent complex of enzyme with a sugar-based amphiphilic polymer is described. The subtilisin Carlsbergpalmitoyl poly(sucrose acrylate) complex was found to be soluble and catalytically active in a number of organic solvents of different nature.     

Multiple attractors,catastrophes and chaos in seasonally perturbed predator-prey communities

A classical predator-prey model is considered in this paper with reference to the case of periodically varying parameters. Six elementary seasonality mechanisms are identified and analysed in detail by means of a continuation technique producing complete bifurcation diagrams. The results show that each elementary mechanism can give rise to multiple attractors and that catastrophic transitions can occur when suitable parameters are slightly changed. Moreover, the two classical routes to chaos, namely, torus destruction and cascade of period doublings, are numerically detected. Since in the case of constant parameters the model cannot have multiple attractors, catastrophes and chaos, the results support the conjecture that seasons can very easily give rise to complex populations dynamics.     

Prognostic value of non-MHC-restricted killer cell activity in lung cancer

The prognostic value of peripheral blood non-MHC-restricted cytotoxicity against the myeloid leukaemic line K562 in lung cancer patients was studied. At the time of diagnosis and before operation, 57 patients with lung cancer were tested for cytotoxicity and subsequently followed for up to 4 years. In addition, 145 lung cancer patients, 30 patients with non-neoplastic lung diseases and 76 healthy donors were tested for cytotoxicity without the follow-up, in order to correlate the stage of lung cancer and the growth rate of tumours to the level of non-MHC-restricted cytotoxicity. On average, lung cancer patients had similar non-MHC-restricted cytotoxicity to the controls. However, patients with stage II–IV diseases showed an impaired activity, stages III and IV differing significantly from the controls. This result shows that the decline in natural killer (NK) activity is associated with tumour burden. Patients with slowly growing neoplasms had stronger cytotoxic activity than patients with fast or moderately progressing disease. In the follow-up study, the whole material of 57 patients showed only a slight correlation between cytotoxicity and survival: 42% of the patients with strong activity survived for more than 2.5 years, whereas 6% of the patients with weak activity did so. In stage I patients there was no correlation between cytotoxicity and survival, nor was there a correlation in patients with stages II–IV of the disease. Hence, in our group of patients the determination of cytotoxicity preoperatively yielded no prognostic information beyound that already available from staging. However, those stage II–IV patients that survived for 1 year or more after the diagnosis and cytotoxicity tests, showed a significant correlation between cytotoxicity and survival.