Phagocytosis in calves and its dynamics after experimental treatment

We evaluated the phagocytic capacity of blood neutrophils and monocytes in calves after nonspecific stimulations of the organisms by colloidal charcoal and concentrated blood derivative administered alone, or enriched by immunomodulator (levamizol). Each of the above-mentioned preparations could be characterized by a specific response of the organism with respect to the phagocytic capacity. After administration of colloidal charcoal, both the phagocytic activity (percent of phagocytizing cells) and the particle-ingesting ability, i.e. phagocytic index, which showed two-phase changes in relation to the administration, were simulated. An increase in the phagocytic index was retained until the end of observation (four weeks), but the phagocytic activity (percent of phagocytizing cells) dropped to the level before administration as soon as in 24 hours. The phagocytic activity was also positively stimulated by the concentrated blood derivative administered alone, and the particle-ingesting ability was not influenced very much. The concentrated blood derivative with immunomodulator could be characterized by a fast increase in the phagocytic activity, accompanied by a successive short-time rise of the phagocytic index. A joint feature of all three preparations was a simultaneous increase in the percent of potential phagocytes and in the values of phagocytic activity. In none of the cases was, however, the increase in phagocytic activity accompanied by a rise in the phagocytic index.     

Effects of fermented cow‐manure on rooting of mung bean cuttings: The role of nutrients and of abscisic acid

The effects of cabutz, an end product of anaerobic fermentation of cow manure, and the effects of its components, on rooting of cuttings were investigated. Cuttings of mung bean (Vigna radiata L. Wilcz.) plants have rooted better in cabutz than in other rooting media. Cabutz extract increased the number of roots of mung bean cuttings as well as their roots length. Similar effects were obtained with a solution containing only the inorganic constituents of cabutz extracts. The complete cabutz extract, but not its mineral components, caused three pronounced effects: (a) it changed the distribution pattern of adventitious roots along the cuttings; (b) it delayed the initiation of roots at the base of the cuttings in the presence of high concentrations of cabutz extract; and (c) it reduced the water loss by cabutz‐treated cuttings. Similar effects were obtained when external abscisic acid was applied in concentrations similar to what was found in cabutz extracts. It is suggested that the effects of cabutz, on the rooting capability of cuttings, are mostly due to two of its components, nitrate and abscisic acid.     

Endoreduplication in maize endosperm: involvement of m phase--promoting factor inhibition and induction of s phase--related kinases

Endoreduplication is an endonuclear chromosome duplication that occurs in the absence of mitosis and in Zea mays (L.) is required for endosperm development. Induction of DNA synthesis during early stages of endosperm development is maintained by increasing the amount and activity of S phase-related protein kinases, which was demonstrated here by their ability to interact with human E2F or with the adenovirus E1A proteins. In addition it was shown that endoreduplicated endosperm cells contain an inhibitor that suppresses the activity of the M phase-promoting factor (MPF). These results demonstrate that in maize endosperm, endoreduplication proceeds as a result of two events, inhibition of MPF and induction of S phase-related protein kinases.