Variation in Osmoregulation in Differentially Drought-Sensitive Wheat Genotypes Involves Calcium

Two wheat (Triticum aestivum L.) genotypes differing in their sensitivity to water deficit (stress tolerant - C306 and stress susceptible - HD2329) were subjected to osmotic stress for 7 d using polyethylene glycol (PEG-6000; osmotic potential –1.0 MPa), at initial vegetative growth. The plants were either supplemented with 1 mM CaCl₂ (Ca²⁺) alone or along with verapamil (VP; calcium channel blocker) to investigate the involvement of calcium in governing osmoregulation. Relative elongation rate (RER), dry matter (DM) production, water potential (_w), electrolyte leakage (EL), contents of proline (Pro) and glycine betaine (GB) and activities of -glutamyl kinase (GK) and proline oxidase (PO) in shoots and roots were examined during stress period. C306 showed relatively higher accumulation of Pro while HD2329 accumulated more GB under stress. RER, DM and _w were relatively higher in C306 than HD2329. Roots compared to shoots showed lower content of osmolytes but had faster rate of their accumulation. Presence of Ca²⁺ in the medium increased the activity of GK and decreased that of PO while in the presence of its inhibitor, decrease in activity of both the enzymes was observed. Ca²⁺ appeared to reduce the damaging effect of stress by elevating the content of Pro and GB, improving the water status and growth of seedlings and minimizing the injury to membranes. The protective effect of Ca²⁺ was observed to be more in HD2329 than C306.     

Identification of calcium-dependent phospholipid-binding proteins (annexins) from guinea pig alveolar type II cells

A new group of calcium-regulating proteins, called annexins or Ca⁺⁺-dependent phospholipid-binding proteins (PLBP), have been detected in different species, organs and cell types. In the present study, we have identified and quantitated PLBP from guinea pig lung, lavage fluid and alveolar type II cells to elucidate the possible role of PLBP in lung surfactant biogenesis and secretion. Lungs were lavaged and type II cells from lavaged lung were isolated by elastase digestion and purified by centrifugal elutriation. For the quantitative identification of PLBP, we performed ELISA assays and Western blot analysis by using an antiserum raised in guinea pigs against a pure rabbit lung 36 kDa PLBP. The lavage fluid, cytosol from lung and type II cells contained 784,167 and 435 ng per mg protein, respectively, of PLBP. The SDS-PAGE electrophoretic pattern and Western blot confirmed that all lung samples have band corresponding to a 36 kDa protein. This indicates that both alveolar type II cells and lavage fluid have higher levels of PLBP than whole lung cytosol.     

Response of the seminal vesicles of the hypophysectomized catfish Heteropneustes fossilis (Bloch) to exogenous androgens,estrogen and corticosteroid†

The response of the regressed seminal vesicles of 136- and 102-day hypophysectomized catfish to 30-day treatment with various steroids has been studied. Hypophysectomy results in complete regression of the seminal vesicles within 40 days. Of the various andro gens tested, ethynyltestosterone and 17 α-methyltestosterone are equipotent in producing weight increment and initiation of secretory activity in the regressed seminal vesicles but are 2.5 times more potent than testosterone propionate. Olive oil, eslradiol benzoate and desoxycorticosterone acetate treatment induce neither secretory activity nor weight increments in the regressed seminal vesicles. The adrenal androgens, 4-androstenedione and dehydroepiandrosterone proved to be weak androgens. The data indicate that only androgens can restore secretory activity in the regressed seminal vesicles of the hypophy sectomized catfish.     

Measurement of waist circumference predicts coronary atherosclerosis beyond plasma adipokines

Objective:

The association of plasma adipokines beyond waist circumference (WC) with coronary artery calcification (CAC), a measure of subclinical atherosclerosis, is unknown.

Design and Methods:

Asymptomatic Caucasian individuals from two community‐based cross‐sectional studies (n = 1,285) were examined and multivariate analysis of traditional risk factors was performed, then WC and adipokines (adiponectin and leptin) were added. Incremental value of each was tested with likelihood ratio testing.

Results:

Beyond traditional risk factors, WC (Tobit regression ratio 1.69, P < 0.001) and plasma leptin (1.57, P < 0.001) but not plasma adiponectin (P = 0.75) were independently associated with CAC. In nested models, neither adiponectin (χ² = 0.76, P = 0.38) nor leptin (χ² = 1.32, P = 0.25) added value to WC beyond traditional risk factors, whereas WC added incremental value to adiponectin (χ² = 28.02, P < 0.0001) and leptin (χ² = 13.58, P = 0.0002).

Conclusion:

In the face of important biomarkers such as plasma adiponectin and leptin, WC remained a significant predictor of CAC beyond traditional risk factors underscoring the importance of WC measurement during cardiovascular risk assessment.     

Promotion of Growth in Mungbean (Phaseolus aureus Roxb.) by Selenium is Associated with Stimulation of Carbohydrate Metabolism

The mungbean plants were grown hydroponically in the absence (control) or presence of 0.1, 0.25, 0.50 and 0.75 ppm selenium (as sodium selenate) for 10 days. The growth of shoots and roots increased with application of selenium with greater extent in shoots. With 0.5 and 0.75 ppm Se levels, the shoot growth was stimulated by 24% to 27% over control, respectively, while the roots showed a corresponding increase of 18-19%, respectively. The shoot-to-root ratio was enhanced significantly with Se application and maximum effects occurred at 0.75 ppm Se. A significant increase was observed in chlorophyll and cellular respiration ability with 0.5 and 0.75 ppm selenium. The increase in growth by selenium was accompanied by elevation of starch, sucrose and reducing sugars. The activity of starch hydrolysing enzymes--amylases and sucrose hydrolysing enzyme--invertase was stimulated significantly with selenium. This was associated with elevation of activities of sucrose synthesising enzymes--sucrose synthase and sucrose phosphate synthase. It was concluded that increase in growth of shoots and roots by application of Se was possibly the result of up-regulation of enzymes of carbohydrate metabolism thus providing energy substrates for enhanced growth.     

Role of Phytohormones in Regulating Heat Stress Acclimation in Agricultural Crops

Heat stress (HS) seriously affects crop growth, causing significant crop yield losses worldwide. The regulatory mechanisms controlling HS tolerance in plants are not well understood. Phytohormones are important molecules for coordinating myriad of phenomena related to plant growth and development. They are also essential endogenous signaling molecules that actively mediate numerous physiological responses under abiotic stress by triggering stress-responsive regulatory genes involved in plant growth. This review updates the central role of various phytohormones—indole acetic acid, gibberellic acid, abscisic acid, cytokinins, ethylene, salicylic acid, brassinosteroids, strigolactone, and jasmonic acid—in regulating the HS response so that plants can adapt to increasing temperature stress. We also reveal how these stress-responsive phytohormones switch on various regulatory gene(s) and genes encoding antioxidants and heat shock proteins (HSPs) to combat HS in various plant species.

     

Substituted 4-methylquinolines as a new class of anti-tuberculosis agents

We report synthesis and anti-tuberculosis activities of a series of novel ring-substituted quinolines. The most effective compound of the series 3d (MIC=6.25 microg/mL, Mycobacterium tuberculosis H37Rv strain) was synthesized in one step; thus is an attractive lead molecule for anti-tuberculosis drug development. The results of this study represent the discovery of ring-substituted 4-methylquinolines as new class of potential anti-tuberculosis agents.     

Downregulation of hippocampal NMDA receptor expression by prenatal exposure to dioxin.

Gestational exposure to the environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin) has been implicated as causative to disparities between ethnic groups with respect to learning disabilities. Dioxin is an extremely toxic environmental pollutant that bioaccumulates in maternal adipose tissue, and is transferred to the developing organism during gestation and lactation. Long-term cognitive deficits have been reported following prenatal exposure to dioxin. N-methyl-D-aspartate (NMDA) receptors in the central nervous system (CNS) have been well known to play an important role in the activity-dependent synaptic plasticity underlying learning and memory and in CNS development including brain cell differentiation. Here, the effects of prenatal exposure to dioxin on the developmental expression profiles of rat hippocampal NMDA receptor subtype 1 mRNA and protein was examined. F-344 rats were exposed to 0 and 700 ng of dioxin/kg on gestational day 15. Real-time PCR and Western blot analysis clearly revealed that dioxin significantly downregulated NMDAR1 mRNA and protein expression during the first postnatal month. The study provides support to the hypothesis that NMDA receptors are important targets for dioxin-induced neurotoxicity in F1 preweaning pups. The results also support the concept that prenatal exposure to dioxin may contribute to the pathogenesis of diseases in the adult.