The Effect of temperature gradient on the transport phenomenon in roots of maize plants grown under salinity conditions. substance,heat, and ion flows

An analysis of flows through primary root and first node root tissues of plants grown under conditions of salinity and nutrient deficiency induced by temperature gradients was carried out using. a mathematical model. The results obtained show that high KNO₃ concentration in Knop’s nutrient solution (salinity) causes an inhibition of volume and heat flows and that the omission of KNO₃ from Knop’s nutrient solution (deficiency) stimulates these flows. The causes of the inhibition lay in the fact that salinity reduced hydraulic, electric, and osmotic conductivity when compared with the control (Knop’s solution), but relative to nutrient deficiency, it increased osmotic conductivity, electrodiffusion, diffusion, and filtration of heat flow induced by the electric and heat power. The causes of the stimulation were that deficiency partially decreased conductivities, similarly as salinity when compared with the control, and also decreased osmotic abilities of the system. By contrast, it increased heat conductivity and corresponding filtrations (diffusion-thermal, thermoosmotic). In first node root tissues, it increased all conductivities with the exception of electric conductivity, then osmotic, electroosmotic, diffusion, electrodiffusion, and filtration of heat flow and current flow, that is the number of possible ways of solution transport through root tissues increased. Part II.     

Contents of volume 183, 1989

Contents of volume 183, 1989     

Propionate metabolism in a methanogenic enrichment culture. Direct reductive carboxylation and acetogenesis pathways

Abstract Serial dilutions of methanogenic sludges in propionate medium gave a methanogenic non-acetoclastic enrichment degrading 1 mol of propionate to 1.6 mol of acetate and 0.17 mol of methane, with a transient accumulation of butyrate. NMR recordings showed the conversion of [2-¹³C]- and [3-¹³C]-propionate to [3-¹³C]- and [4-¹³C]-butyrate, respectively, thus demonstrating a reductive carboxylation of propionate to butyrate. The labelling found in the accumulated acetate and fermentation balances also suggested that reductive carboxylation was the major pathway involved in propionate conversion to acetate.     

The apparent reversal of a wasting syndrome by nutritional intervention in Saguinus mystax

One hundred eighty sexually mature Saguinus mystax were imported from Peru in six lots over a period of 1 year. Within 1 year after arrival, the mortality was 60% and the majority of the tamarins showed signs similar to "wasting marmoset syndrome" (WMS). In an effort to improve the survival rate, an open formula diet replaced the commercial closed formula diet that had been fed since arrival of the tamarins. The open formula diet contained 26.2% crude protein, 12.3% ether extract, 43.3% nitrogen free extract and 5.9% crude fiber on a dry matter basis. The diet was evaluated on the basis of palatability, weight gain, mortality, digestibility, nitrogen balance, serum biochemical parameters and blood counts. The mean daily consumption on an as-is basis was 44.8g or 335 Kcal gross energy/Kg of body wt./day. During the 3 month open formula diet evaluation period average weight increased by 56g (p less than .05), mortality decreased demonstratively, and alopecia and chronic diarrhea were nearly eliminated. Mean daily gross energy intake for S. mystax (335 Kcal/Kg of body wt/day) was substantially greater than previously reported values for callitrichids. WMS signs observed in the S. mystax colony were controlled by providing what appears to be an adequate diet.     

High performance liquid chromatography and biotechnological application of several oxidoreductases

This paper describes our experience with the use of high performance liquid chromatography in the analysis and preparation of several NAD-dependent dehydrogenases and oxygen-dependent oxidases. The chromatographic materials tested were from Pharmacia (Sweden), LKB (Sweden) and Lachema (Czechoslovakia), the columns were attached to the fast protein liquid chromatographic (FPLC) system from Pharmacia. The preparative use of high performance ion exchange, molecular sieve and hydrophobic interaction chromatographies as well as of chromatofocusing made it possible to prepare tens of milligrams of completely pure enzymes in several hours. In most cases a combination of two high performance methods was sufficient to yield a homogeneous enzyme. The purified enzymes were used as analytical reagents for determining the concentrations of several metabolites and activities of some enzymes. A biotechnological application of immobilized alcohol dehydrogenase for the production of reduced nicotineadenine dinucleotide from the oxidized form of the coenzyme is discussed in a greater detail.     

Inhibition of the morphine withdrawal syndrome by a novel muscarinic antagonist (4-DAMP)

It has been recognized for many years that central cholinergic neurons are susceptible to inhibition by opiates and that during withdrawal their firing rates are enhanced. Nevertheless, classical nonselective muscarinic receptor antagonists have not been demonstrated to provide consistent inhibition of withdrawal symptoms in humans or in animal models. The purpose of this study was to determine whether selective blockade of central M1 or M2 muscarinic receptor subtypes could provide inhibition of naloxone precipitated withdrawal symptoms in morphine dependent rats. As with earlier human studies, both cardiovascular and behavioral measures of withdrawal were quantitated. The selective M2 receptor antagonist 4-DAMP was significantly more effective than the M1 antagonist pirenzepine in reducing both cardiovascular and behavioral symptoms. These results are consistent with a role for cholinergic neurons in the expression of certain morphine withdrawal symptoms and suggest that future therapies might be targeted towards central M2 receptors.