Wyniki wyszukiwania - Biblioteka Nauki

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100%

Sirko A. , Brodzik R.

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nr 4

EN

Both urea and urease were subjects of early scientific investigations. Urea was the first organic molecule to be synthesized and jack bean urease was the first enzyme ever to be crystallized. About 50 years later it was shown to be the first nickel metalloenzyme. Since then, nickel-dependent ureases have been isolated from many bacteria, fungi and higher plants. They have similar structures and mechanisms of catalysis. A urease apoenzyme needs to be activated. This process requires participation of several accessory proteins that incorporate nickel into the urease forming catalytic site. In this review, ureases from various organisms are briefly described and the similarities of their structures discussed. Moreover, the significance of urea recycling in plants is explained and recent literature data about the function and activation of plant ureases are presented.

2

Professor Jan Kowalczyk on the 50th anniversary of his professional career and 70th birthday

72%

Zebrowska T.

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nr 1

3

The effect of exogenous proteases on selected hematological and serum biochemical parameters in boars

58%

Zielonka L. , Przewoski W. , Gajecka M. , Jakimiuk E. , Gajecki M.

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nr 1

151-156

EN

The increasing interest in enzymatic growth promoters prompted this investigation of the effect of an enzymatic stimulating complex on selected hematological and serum biochemical parameters in boars. The enzymatic complex [five proteases (proteinases-endopeptidases) and two peptidases (exopeptidases) obtained by fermentation from Streptomyces fradiae] was added to diets for three months, at initial doses of 90 (group El) and 120 (group E2) g/ton feed for the first seven days followed by 40 and 60 g/ton, respectively, in the subsequent weeks. The evaluation was based on selected hematological (RBC, WBC, HCT (Ht), HGB (Hb), MCV, MCH, and MCHC) and biochemical (AST, ALT, AP, Ca, Mg, urea, cholesterol, creatinine, inorganic phosphorus, and oxyglucose) parameters determined before and after the experimental period. The reported values were within physiological norms. Statistical differences were found between experimental groups with respect to WBC, HCT (Ht), MCV, MCH, AP, Ca, Mg, creatinine, and inorganic phosphorus. The study results indicate that the complex of proteolytic enzymes administered to boars caused no negative changes in their metabolic profiles. The statistically different hematological and serum biochemical parameters, while within normal limits, point to an early stage of microcytic anemia and heightened agitation that could be the result of intensified nitrogen metabolism.

4

The effect of plant biostimulation with ‘Pentakeep V’ and nitrogen fertilization on yield, nitrogen metabolism and quality of spinach

51%

Smolen S. , Sady W. , Wierzbinska J.

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nr 1

EN

Foliar application of fertilizers containing biostimulators can influence yield and the uptake and accumulation of NO3- by plants. The aim of the research was to determine the influence of foliar nutrition with ‘Pentakeep V’ and diverse doses of nitrogen fertilization on yield, plant nitrogen metabolism and nutritional quality of spinach. The experiment design included two sub-blocks with and without foliar nutrition. Plants with foliar nutrition were sprayed twice with 0.02% w/v ‘Pentakeep V’ fertilizer (3000 dm3 water per 1 ha). In each sub-block soil nitrogen fertilization (in the form of ammonium nitrate) was applied in following combinations: 1 – control (without N), 2 – 50% N dose prior to seed sowing (25 mg N∙dm-3 of soil), 3 – 100% N dose prior to seed sowing (50 mg N∙dm-3 of soil). The interaction between foliar nutrition and nitrogen fertilization had a significant effect on the content of: nitrates(V), soluble oxalates and ascorbic acid in spinach leaves. The effect of tested factors on the content of nitrates(V) and ascorbic acid was additionally modified by the weather conditions in both years of research. Foliar application of ‘Pentakeep V’ resulted in decreased concentration of soluble oxalates in control plants (without N) as well as higher amount of these compounds in plants fertilized with 100% of N dose. No significant effect of tested interaction was observed in the case of yield and the content of: dry matter, nitrates(III), ammonium ions, free amino acids, N-total, soluble sugars and phenolic compounds in spinach leaves.

PL

Dolistna aplikacja nawozów zawierających biostymulatory może wpływać na plon oraz na pobieranie i akumulację NO3- przez rośliny. Celem badań było określenie wpływu dokarmiania dolistnego nawozem ‘Pentakeep V’ oraz zróżnicowanego pod względem dawki nawożenia azotem na plonowanie, gospodarkę azotem roślin oraz jakość odżywczą szpinaku. Badaniami objęto dwa podbloki z dolistnym i bez dolistnego dokarmiania roślin. Rośliny dokarmiano dolistnie dwukrotnie nawozem ‘Pentakeep V’ w dawce 0,02% m/o, stosując w przeliczeniu 3000 dm3 wody na hektar. W obrębie podbloków zastosowano doglebowe przedsiewne nawożenie azotem (w formie saletry amonowej): 1 – kontrola (nienawożona azotem), 2 – 50% dawki N (25 mg N∙dm-3 gleby), 3 – 100% dawki N (50 mg N∙dm-3 gleby). Stwierdzono istotny wpływ współdziałania dokarmiania dolistnego z nawożeniem azotem na zawartość azotanów(V), szczawianów rozpuszczalnych i kwasu askorbinowego w szpinaku. Oddziaływanie tych czynników na zawartość azotanów(V) i kwasu askorbinowego w szpinaku uzależnione było jednak od przebiegu warunków klimatycznych. Dokarmianie dolistne roślin nawozem ‘Pentakeep V’ powodowało obniżenie zawartości szczawianów rozpuszczalnych w roślinach kontrolnych oraz wzrost zawartości tych związków w roślinach nawożonych 100% dawki N. Stwierdzono brak współdziałania dokarmiania dolistnego z nawożeniem azotem na plon oraz na zawartość suchej masy, azotanów(III), jonów amonowych, wolnych aminokwasów, N-ogółem, cukrów rozpuszczalnych i związków fenolowych w szpinaku.