Changes in carbohydrate composition in wheat and pea seedlings induced by calcium deficiency

Wheat (Triticum aestivum L. cv Jubilar) seedlings were grown for 10 days in hydroponics with or without calcium. In the leaves, Ca deficiency caused the level of ethanol soluble carbohydrate to increase between 2-and 10-fold, enhanced dark respiration and decreased CO₂ fixation capacity. Sucrose was the major carbohydrate to accumulate in wheat roots.     

Production of microsporidia pathogenic to the Colorado potato beetle (Leptinotarsa decemlineata) in alternate hosts

The microsporida Nosema gastroideae and N. equestris, which are highly pathogenic for Leptinotarsa, have been successfully produced in some other chrysomelid species, Gastrophysa polygoni and G. viridula. As the principal target host, Leptinotarsa is very susceptible to these pathogens, and death occurs before massive sporulation by the microsporidia. By contrast, the infected larvae of G. polygoni or G. viridula are able to develop until the adult stage when most of the tissues become filled with spores. In addition, the larvae and adults of these species can be reared in the laboratory on Polygonum aviculare and Rumex obtusifolius. These plants have longer vegetative periods and are better sources of food than potato leaves. In both species of Gastrophysa the yields of spores related to unit weight were about five times higher than in Leptinotarsa. In the adults of G. viridula there was up to 4.8 × 10⁶ spores mg^?1 body weight of N. gastroideae, or 9.1 × 10⁶ spores mg^?1 of N. equestris. The higher content of microsporidian spores facilitates their purification and isolation.     

Respiration and microflora of the rhizosphere soil of wheat influenced by foliar application of urea

The numbers of micromycetes and bacteria were investigated with respect to oxygen consumption in the rhizosphere soil of wheat and in non-rhizosphere soil. Plants after foliar application of urea (2 % solution) and non-treated plants were cultivated in degraded chernozem and garden soil in a green-house. Changes in oxygen consumption by the suspensions of rhizosphere and non-rhizosphere soils corresponded to changes in the number of bacteria designated as the rhizosphere effect (R/S). Values of R/S depended on the presence of organic substrates. Changes in oxygen consumption by the soil suspension from the rhizosphere of wheat occurring due to foliar application of urea corresponded to changes in the amount of microflora. The results obtained are discussed with respect to a possible utilization of the data to follow metabolic activity of soils in a natural environment (in situ) determined according to oxygen consumption by a soil suspension, and to assess changes in the microflora of rhizosphere and non-rhizosphere soil.     

Passage of foreign proteins across the intestinal wall of newborn rabbits

Foreign proteins penetrate across the wall of rabbit jejunum takes place within the first eight hours after birth. Sensitization by foreign protein (cow's milk protein) during early postnatal ontogeny is the cause of death of artificially fed germfree rabbits at the age of 21-23 d.     

Translation of poly(U) on ribosomes from Streptomyces aureofaciens

Slowly cooled cells of Streptomyces aureofaciens contained mainly tight-couple ribosomes. Maximum rate of polyphenylalanine synthesis on ribosomes of S. aureofaciens was observed at 40°C, while cultures grew optimally at 28°C. Ribosomes of S. aureofaciens differed from those of E. coli in the amount of poly(U) required for maximum synthetic activity. The polyphenylalanine-synthesizing activity of E. coli ribosomes was about 3-times higher than that of S. aureofaciens ribosomes. The addition of protein S1 of E. coli or the homologous protein from S. aureofaciens had no stimulatory effect on the translation of poly(U). In order to localize alteration(s) of S. aureofaciens ribosomes in the elongation step of polypeptide synthesis we developed an in vitro system derived from purified elongation factors and ribosomal subunits. The enzymatic binding of Phe-tRNA to ribosomes of S. aureofaciens was significantly lower than the binding to ribosomes of E. coli. This alteration was mainly connected with the function of S. aureofaciens 50 S subunits. These subunits were not deficient in their ability to associate with 30 S subunits or with protein SL5 which is homologous to L7/L12 of E. coli.     

The problem of carotenoid biosynthesis in the taxonomy of genera Rhodotorula and Rhodosporidium

This report presents results in the composition of major carotenoids of various coloured mutants of the genusRhodotorula and of mating types of the genusRhodosporidium. The separation of carotenoid intermediates was carried out by thin layer chromatography using Silufol 254 Kavalier and the determination of eluated spots by spectrophotometry. There was found no difference in carotenoid composition of both mating typesa and α of individual species of the genusRhodosporidium. The vegetative and sexual reproduction ofRhodotorula andRhodosporidium can be separated from the carotenogenesis using 10^?4 mol diphenylamine. It was concluded that lycopene could be the intermediate to mono- and dicyclic carotenoids; in the case of partial inhibition of the dehydrogenation step the direct cyclization of neurosporene to β-zeacarotene can be expected. An unknown compound, probably lycopersene was found and was considered to be the precursor of phytoene. Phytoene and phytofluene were proved in all studied samples. Nutritional conditions (vitamins, sulfur amino acids, etc.) are able to shift the ratios between major carotenoids. Rhodotorula aurantiaca strains were observed to be auxotrophic mutants of various characters and the existence of this species as independent one, was denied.