Effects of anoxia and flooding on alcohol dehydrogenase in roots of Glyceria maxima and Pisum sativum

Flood tolerant Glyceria maxima and intolerant Pisum sativum were compared in respect of the effects of anoxia and flooding on the maximum catalytic activities of alcohol dehydrogenase in their roots. Small (<73%) increases in enzyme activity occurred when excised roots of both species were incubated in nitrogen for up to 2 days. Further incubation in nitrogen rapidly and permanently damaged the roots of both species. Enzyme activity in flooded roots of Glyceria was about double that in corresponding non-flooded roots. A marginally greater difference was found for roots of Pisum. It was concluded that the two species respond so similarly to the above treatments that variation in the extent of induction of alcohol dehydrogenase is unlikely to be a significant factor in determining their ability to tolerate flooding.     

Starch breakdown in the spadix of Arum maculatum

The aim of this work was to discover the pathway of starch breakdown during thermogenesis in the club of the spadix of Arum maculatum. The conventional α-amylase of higher plants could not be demonstrated in extracts of clubs although such extracts did exhibit considerable hydrolytic activity towards starch. This activity had an action pattern characteristic of an endo-amylase, was destroyed by heating to 70°, and was not inhibited by either 7 mM ethylenediaminetetra-acetic acid or 100 mM N-ethyl maleimide. Measurements of this hydrolytic activity, and of the maximum catalytic activities of starch phosphorylase, phosphoglucomutase and hexokinase, were made at different stages of club development. These measurements were compared with estimates of the rate of starch breakdown at thermogenesis. This comparison indicates that phosphorolytic cleavage does not play a large role in such starch breakdown, and that this process is mediated, mainly, by the hydrolytic activity, described above, and by hexokinase.     

Measurements of glycolytic intermediates during the onset of thermogenesis in the spadix of Arum maculatum

1. This work was done to compare the amounts of glycolytic intermediates in the club of the spadix of Arum maculatum L. at an early stage (α) of development, immediately prior to the increase in glycolysis (pre-thermogenesis), and at the peak of the rapid glycolysis (thermogenesis).2. Glucose 1-phosphate, glucose 6-phosphate, fructose 6-phosphate, 3-phosphoglycerate, 2-phosphoglycerate, phosphoenolpyruvate and pyruvate were measured. The results indicate that at all the above stages of club development the reactions catalysed by phosphoglucomutase, glucosephosphate isomerase, phosphoglycerate mutase and enolase were close to equilibrium, but those catalysed by phosphofructo-kinase and pyruvate kinase were considerably displaced from equilibrium.3. The amounts of the above compounds per club increased 5-fold between α stage and pre-thermogenesis but the relative amounts remained unchanged. When glycolysis increased by more than 50-fold at thermogenesis, the amount of fructose 1,6-diphosphate per club rose, but no changes were detected in the amounts per club of any of the other compounds listed above. These results are discussed in relation to the control of glycolysis.     

Analysis of Growth and Productivity of Green Chickpea Using Nitrogen and Phosphorus Fertilization

Chickpea contains high levels of protein, vitamins and minerals. Acceptable chickpea yield is the result of meeting nitrogen and phosphorus requirements. The effect of appropriately meeting such requirements reflects on growth and can easily be evaluated using growth analysis. This research determined: (a) The effect of nitrogen and phosphorus fertilization on phenology, net assimilation rate, number of green leaves, leaf area, leaf area index and leaf area duration; (b) Green chickpea yield and number of pods due to fertilization; and (c) The combination of nitrogen and phosphorus fertilization that yields the most net revenue. Nitrogen and phosphorus fertilization was evaluated; each at the doses of 0, 75 and 150 kg ha^–1 (N0, N75, N150; P0, P75 and P150, respectively). The combination of the levels of both nutrients generated nine combinations of treatments which were distributed in the field in a randomized complete block design in an arrangement of divided plots with four repetitions. Timing of phenological phases were similar among treatments. Nitrogen and phosphorus fertilization increased number of leaves, leaf area index, and leaf area duration that translated into increased green chickpea yield (GCY). Combinations N150-P75 and N150-P150 produced the highest GCY. The highest net revenue and revenue per peso invested was obtained with N150-P75.     

Affinity of Ionic Species of Nucleoside Transport Protein Inhibitors

Abstract

A class of very potent nucleoside transport inhibitors is present in two molecular forms around physiological pH. We investigated whether the monoprotonated or the unionized species of these molecules binds to this camer protein with higher affinity.     

Microcolonial Fungi on Rocks: A Life in Constant Drought?

Black microcolonial fungi (MCF) and black yeasts are among the most stress-resistant eukaryotic organisms known on Earth. They mainly inhabit bare rock surfaces in hot and cold deserts of all regions of the Earth, but some of them have a close phylogenetic relation to human pathogenic black fungi which makes them important model organisms also with respect to clinical mycology. The environment of those fungi is especially characterized by extreme changes from humidity to long periods of desiccation and extreme temperature differences. A key to the understanding of MCF ecology is the question about metabolic activity versus dormancy in the natural environments. In this study, the time lag from the desiccated state to rehydration and full metabolic activity and growth was measured and defined in accordance with simulated environmental conditions. The ability to survive after desiccation and the speed of rehydration as well as changes of the whole cell protein pattern are demonstrated. Whereas both mesophilic strains—Exophiala jeanselmei and Knufia perforans (=Coniosporium perforans)—show a clear reaction toward desiccation by production of small proteins, Cryomyces antarcticus—the extremotolerant MCF—does not show any response to desiccation but seems just to down-regulate its metabolism. Data on intracellular sugar suggest that both trehalose and mannitol might play a cell protective role in those fungi.     

Roles of M3 receptor in the effect of penehyclidine hydrochloride upregulated beta-arrestin-1 expression in LPS-stimulated HPMVEC

Background: This study is to investigate the roles of muscarinic receptor 3 (M₃ receptor) in the effect of penehyclidine hydrochloride (PHC) upregulated beta-arrestin-1 expression in lipopolysaccharide (LPS)-stimulated human pulmonary microvascular endothelial cell (HPMVEC).

Methods: HPMVECs were transfected with a shRNA-containing plasmid that specifically targets M₃ receptor mRNA. Cells were collected to measure F-actin contents, levels of intercellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1), as well as changes of F-actin cytoskeleton arrangement by Laser scanning confocal. Beta-arrestin-1 protein expressions were determined by Western blot and beta-arrestin-1 mRNA expressions were measured by Real-time PCR.

Results: Similar to normal cells, PHC could also increase F-actin contents and beta-arrestin-1 expressions, reduce ICAM-1 and VCAM-1 expressions, and inhibit LPS-stimulated reorganization of F-actin and formation of stress fiber in M₃ receptor shRNA group. Compared with normal cells, F-actin cytoskeleton was neat, ICAM-1 and VCAM-1 expressions were decreased, as well as F-actin contents were increased in M₃ receptor shRNA group. However, there were no differences in beta-arrestin-1 expressions between normal cell groups and M₃ receptor shRNA groups.

Conclusion: These results indicate that M₃ receptor plays an important role in pulmonary microvascular endothelial barrier function, and knock-out of M₃ receptor could attenuate LPS-induced pulmonary microvascular endothelial injury. However, upregulative effect of PHC on beta-arrestin-1 expression is independent with presence of M₃ receptor.     

Trehalose degradation and glucose efflux precede cell ejection during germination of heat-resistant ascospores of Talaromyces macrosporus

Talaromyces macrosporus forms ascospores that survive pasteurization treatments. Ascospores were dense (1.3 g ml(-1)), relatively dry [0.6 g H(2)O (g dry weight)(-1)] and packed with trehalose (9-17% fresh weight). Trehalose was degraded to glucose monomers between 30 and 100 min after heat activation of the spores. The maximal activity of trehalase was calculated as 400-520 nmol glucose formed min(-1) (mg protein)(-1) as judged by measurements of the trehalose content of spores during germination. During early germination, glucose was released from the cell (10% of the cell weight or more). The intracellular concentration of glucose only peaked briefly. After 160-200 min, the protoplast encompassed by the inner cell wall was ejected through the outer cell wall in a very quick process. Subsequently, respiration of spores increased strongly. The data suggested that trehalose is primarily present for the protection of cell components as glucose is released from the cell. Then, an impenetrable outer cell wall is shed before metabolic activity increases.     

p27(Kip1) is an inducer of intestinal epithelial cell differentiation

Constant renewal of the intestinal epitheliumis a highly coordinated process that has been subject to intenseinvestigation, but its regulatory mechanisms are still essentiallyunknown. In this study, we have demonstrated that forced expression ofthe cyclin-dependent kinase inhibitors (CKIs) p27^Kip1 andp21^Cip1/WAF1 in human intestinal epithelial cells led toexpression of differentiation markers at both the mRNA and proteinlevels. Cell differentiation was temporally dissociated from inhibitionof retinoblastoma protein phosphorylation and growth arrest, alreadyestablished 1 day after infection with recombinant adenoviruses.p27^Kip1 proved significantly more efficient thanp21^Cip1/WAF1 in induction of cell differentiation. Incontrast, forced expression of p16^INK4a resulted in growtharrest without induction of differentiation markers. These resultsimplicate both p27^Kip1 and p21^Cip1/WAF1 in thedifferentiation-timing process, but p21^Cip1/WAF1 may actindirectly by increasing p27^Kip1 levels. These results alsosuggest that induction of intestinal epithelial cell differentiation byCKIs is not related to their effects on the cell cycle and may involveinteractions with cellular components other than cyclins andcyclin-dependent kinases.