Role of nuclear PKC delta in mediating caspase-3-upregulation in Jurkat T leukemic cells exposed to ionizing radiation

The suppressive role of endogenous regucalcin (RC), which is a regulatory protein of calcium signaling, in the enhancement of protein phosphatase activity (PPA) in the cytosol and nucleus of kidney cortex in calcium-administered rats was investigated. Calcium content in the kidney cortex was significantly increased at 0.5-5 h after a single intraperitoneal administration of calcium chloride solution (10 mg Ca/100 g body weight) to rats. The analysis with Western blotting of RC protein showed that RC levels in the cytosol and nucleus were significantly increased 0.5-5 h after the administration of calcium (10 mg/100 g). PPA toward phosphotyrosine, phosphoserine, and phosphothreonine was found in the cytosol and nucleus of kidney cortex. PPA toward three phosphoamino acids in the cytosol and nucleus was significantly increased by the administration of calcium (10 mg/100 g). The presence of anti-RC monoclonal antibody (25 ng/ml) in the enzyme reaction caused a significant increase in PPA toward phosphotyrosine, phosphoserine, and phosphothreonine in the cytosol and nucleus of kidney cortex in normal rats. The effect of anti-RC monoclonal antibody (25 ng/ml) in increasing PPA toward three phosphoamino acids in the cytosol and nucleus was significantly enhanced in calcium-administered rats. The effect of anti-RC monoclonal antibody (25 ng/ml) in increasing PPA in the cytosol and nucleus of normal rats and calcium-administered rats was completely abolished by the addition of RC (10(- 6) M) in the enzyme reaction mixture. The present study suggests that endogenous RC suppresses the enhancement of PPA in the cytosol and nucleus of kidney cortex in calcium-administered rats.     

Host plant nodule parameters associated with nitrogen fixation efficiency in French bean (Phaseolus vulgaris L) cultivars

Two cultivars of French bean (Phaseolus vulgaris L.) viz. contender and arka komal were planted in polythene bags containing sand and grown under glasshouse conditions. The nodulation status, shoot/root biomass, activities of several nodule enzymes, total soluble protein and leghaemoglobin contents were monitored over the entire growth period. Allantoinase activity in leaves was measured to monitor the ureide degrading capacity. Significant genotype difference was observed in both the cultivars. All the parameters showed a decline after flowering except uricase, which declined before flowering. Malate dehydrogenase and isocitrate dehydrogenase showed a constant decline throughout the growth period. Degree of decline varied with the genotype for all the parameters. Leghaemoglobin content, PEP carboxylase activity and ureide degrading capacity of leaves did not show an appreciable decline in contender and were significantly higher than in arka komal. These factors can be used to increase nitrogen fixation in French bean.     

Does shoot water status limit leaf expansion of nitrogen-deprived barley?

The role of shoot water status in mediating the decline in leaf elongation rate of nitrogen (N)-deprived barley plants was assessed. Plants were grown at two levels of N supply, with or without the application of pneumatic pressure to the roots. Applying enough pressure (balancing pressure) to keep xylem sap continuously bleeding from the cut surface of a leaf allowed the plants to remain at full turgor throughout the experiments. Plants from which N was withheld required a greater balancing pressure during both day and night. This difference in balancing pressure was greater at high (2.0 kPa) than low (1.2 kPa) atmospheric vapour pressure deficit (VPD). Pressurizing the roots did not prevent the decline in leaf elongation rate induced by withholding N at either high or low VPD. Thus low shoot water status did not limit leaf growth of N-deprived plants.     

Syntheses of novel substituted-boranophosphate nucleosides

A number of substituted (borano) nucleic acids, 3'-[diethylphosphite(cyano, carboxy, or carbamoyl) borano] deoxynucleosides (3a-4c) and 5'-[diethylphosphite(cyano or carboxy) borano] deoxynucleosides (6a-7d) were prepared by a variety of synthetic procedures. The syntheses of the pyrophosphates (2a-2c), as precursors for 3a-4c, are also described.     

Ecology of dermatophytes and other keratinophilic fungi in swimming pools and polluted and unpolluted streams

The biodiversity and richness of keratinophilic fungal communities including dermatophytes were assessed in three stream sites and three swimming pools in the Nablus district in Palestine, using hair baiting (HBT) and surface dilution plate (SDP) techniques, over 8- and 6-month periods, respectively. The effect of wastewater effluent and selected ecological factors on these fungi in relation to species diversity and population densities were also considered. Fifty keratinophilic fungal species were recovered from the aquatic habitats studied, of which 42 were recovered from stream sites and 22 from swimming pools. Of these fungi 6 were either dermatophytes (Microsporum gypseum, and Trichophyton mentagrophytes) or dermatophyte related species (Chrysosporium merdarium, Ch. tropicum, Ch. keratinophilum and T. terrestre). The most frequently isolated species in the three pools were Acremonium strictum and Cladosporium cladosporioides, using Sabouraud dextrose agar medium (SDA). The most abundant species were Acr. strictum, and Aspergillus flavus. However, only 4 species were isolated using the SDA medium amended with 5-flurocytosine (5-FC). The most frequent and abundant species in the three stream sites using SDA medium were Geotricum candidum, and Penicillium chrysogenum. The most frequent species in the three sites using the 5-FC medium, was Paecilomyces lilacinus. Using HBT, the most abundant and frequent species in the three stream sites were G. candidum, and Pa. lilacinus, on SDA medium, and Pa. lilacinus, and Gliocladium nigrovirens on the 5-FC medium. The 5-FC medium was more suitable for the isolation of dermatophytes and closely related species than the SDA medium; 6 were recovered on 5-FC, whereas only one on the SDA medium. Variation in the levels of keratinophilic fungal populations from the three stream sites sampled 5 times over an 8-month period, followed comparable fluctuation patterns. Wastewater affected fungal population densities with the highest levels in the un-polluted stream sites, and lowest in the heavily polluted sites. Swimming pools, polluted and un-polluted stream sites were found to be rich in pathogenic and potentially pathogenic fungi.     

Ca2+-overload inhibits the cardiac SR Ca2+-calmodulin protein kinase activity

There is increasing evidence to suggest that Ca2+-calmodulin dependent protein kinase (CaMK) regulates the sarcoplasmic reticulum (SR) function and thus plays an important role in modulating the cardiac performance. Because intracellular Ca2+-overload is an important factor underlying cardiac dysfunction in a heart disease, its effect on SR CaMK was examined in the isolated rat heart preparations. Ca2+-depletion for 5 min followed by Ca2+-repletion for 30 min, which is known to produce intracellular Ca2+-overload, was observed to attenuate cardiac function as well as SR Ca2+-uptake and Ca2+-release activities. Attenuated SR function in the heart was associated with reduced CaMK phosphorylation of the SR Ca2+-cycling proteins such as Ca2+-release channel, Ca2+-pump ATPase, and phospholamban, decreased CaMK activity, and depressed levels of SR Ca2+-cycling proteins. These results indicate that alterations in cardiac performance and SR function following the occurrence of intracellular Ca2+-overload may partly be due to changes in the SR CaMK activity.     

Relaxation kinetics and the glassiness of proteins: the case of bovine pancreatic trypsin inhibitor

Folded proteins may be regarded as soft active matter under physiological conditions. The densely packed hydrophobic interior, the relatively molten hydrophilic exterior, and the spacer connecting these put together a large number of locally homogeneous regions. For the case of the bovine pancreatic trypsin inhibitor, with the aid of molecular dynamics simulations, we have demonstrated that the kinetics of the relaxation of the internal motions is highly concerted, manifesting the protein's heterogeneity, which may arise from variations in density, local packing, or the local energy landscape. This behavior is characterized in a stretched exponential decay described by an exponent of approximately 0.4 at physiological temperatures. Due to the trapped conformations, configurational entropy becomes smaller, and the associated stretch exponent drops to half of its value below the glass transition range. The temperature dependence of the inverse relaxation time closely follows the Vogel-Tamman-Fulcher expression when the protein is biologically active.     

Protein kinase C zeta nuclear translocation mediates the occurrence of radioresistance in friend erythroleukemia cells

Friend erythroleukemia cells require high doses (15 Gy) of ionizing radiation to display a reduced rate of proliferation and an increased number of dead cells. Since ionizing radiation can activate several signaling pathways at the plasma membrane which can lead to the nuclear translocation of a number of proteins, we looked at the intranuclear signaling system activated by Protein Kinases C, being this family of enzymes involved in the regulation of cell growth and death. Our results show an early and dose-dependent increased activity of zeta and epsilon isoforms, although PKC zeta is the only isoform significantly active and translocated into the nuclear compartment upon low (1.5 Gy) and high (15 Gy) radiation doses. These observations are concomitant and consistent with an increase in the anti-apoptotic protein Bcl-2 level upon both radiation doses. Our results point at the involvement of the PKC pathway in the survival response to ionizing radiation of this peculiar cell line, offering PKC zeta for consideration as a possible target of pharmacological treatments aimed at amplifying the effect of such a genotoxic agent.