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With the advent of numerous candidate drugs for therapy in cystic fibrosis (CF), there is an urgent need for easily interpretable assays for testing their therapeutic value. Defects in the cystic fibrosis transmembrane conductance regulator (CFTR) abolished beta-adrenergic but not cholinergic sweating in CF. Therefore, the beta-adrenergic response of the sweat gland may serve both as an in vivo diagnostic tool for CF and as a quantitative assay for testing the efficacy of new drugs designed to restore CFTR function in CF. Hence, with the objective of defining optimal conditions for stimulating beta-adrenergic sweating, we have investigated the components and pharmacology of sweat secretion using cell cultures and intact sweat glands. We studied the electrical responses and ionic mechanisms involved in beta-adrenergic and cholinergic sweating. We also tested the efficacy of different beta-adrenergic agonists. Our results indicated that in normal subjects the cholinergic secretory response is mediated by activation of Ca(2+)-dependent Cl(-) conductance as well as K(+) conductances. In contrast, the beta-adrenergic secretory response is mediated exclusively by activation of a cAMP-dependent CFTR Cl(-) conductance without a concurrent activation of a K(+) conductance. Thus, the electrochemical driving forces generated by beta-adrenergic agonists are significantly smaller compared with those generated by cholinergic agonists, which in turn reflects in smaller beta-adrenergic secretory responses compared with cholinergic secretory responses. Furthermore, the beta-adrenergic agonists, isoproprenaline and salbutamol, induced sweat secretion only when applied in combination with an adenylyl cyclase activator (forskolin) or a phosphodiesterase inhibitor (3-isobutyl-1-methylxanthine, aminophylline or theophylline). We surmise that to obtain consistent beta-adrenergic sweat responses, levels of intracellular cAMP above that achievable with a beta-adrenergic agonist alone are essential. beta-Adrenergic secretion can be stimulated in vivo by concurrent iontophoresis of these drugs in normal, but not in CF, subjects.

Brassica napus L is an important oilseed crops grown throughout many parts of the world. It is well adapted to long day photoperiods. Synthetic B. napus was produced through interspecific hybridization between B. rapa L. var Tori-7 and exotic variety of B. oleracea L. var. alboglabra Bailey. The chromosomes of the interspecific hybrids were doubled through the treatments of colchicine. Synthetic B. napus had increased growth and exhibited wider range of variations than parents for plant height leaf and floral characters, siliquae related characters, flowering and maturity characters, yield and yield contributing characters and sterility and siliquae shattering characters. Resynthesized lines (RS) showed higher plant height, leaf width compare to check variety BINA Sarisha-04. The RS lines also found to be best for siliquae related characters (siliquae length, break length, length of main fruiting axis, siliquae density siliquae angle). On the basis of flowering and maturity characters (1st, 50% and 90% flowering and days to maturity) RS lines showed six days earlier than check variety but not early maturing B. rapa parent Tori-7. The RS lines found to be promising for yield, yield contributing characters and oil content (primary and secondary branches per plant, siliquae per plant, seeds per plant, 1000 seeds weight, seed yield per plant and oil content). On the basis of sterility and shattering characters (pollen sterility %, siliquae setting, sterile seeds per siliquae, siliquae shattered at harvest and siliquae shattered after 7 days of harvest) the RS lines were better performer than check variety. The developed RS lines may be useful for rapeseed breeding to improve earliness, shattering tolerance and higher yield. [ABSTRACT FROM AUTHOR]

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Chilli is an important cash crop in Bangladesh but average yield is very low (0.89 t ha-1) and genetic potentiality of Bangladeshi chilli landraces for hybrid variety development has not been evaluated. The objective of this study was to find out heterotic behavior following Gardner and Eberhart model (1966) II. Six different homozygous divergent parents CCA 2, CCA 5, BARI Morich 1, CCA 11, CCA 15 and CCA 19 were used to estimate heterosis. A significant amount of heterosis was present in yield and yield contributing traits. Estimate of variety heterosis for yield per plant was significantly positive in CCA 5 and BARI Morich 1. In BARI Morich 1, the significant and positive variety heterosis for yield per plant was associated with significant and positive estimates of heterosis for number of fruits per plant and number of seeds per fruit, suggesting that these yield traits contributed to the final heterosis manifested through yield. Indigenous×exotic crosses showed significant amount of heterosis. It is possible to emphasize indigenous×exotic crosses for good fruit yield, particularly to be used as commercial hybrids. Hybrids of BARI Morich 1×CCA 19 and CCA 5×BARI Morich 1 showed better performance. [ABSTRACT FROM AUTHOR]

A cluster of three ethylene response factor (ERF) like genes at the SUB1 locus has been reported from rice variety FR13A that confers tolerance to submergence for about 14 days and SUB1 gene-expression was studied. However, SUB1 gene-expression variation in rice hybrids developed from different tolerant parents is useful to understand distinct submergence tolerance mechanisms. In this investigation, we used semi-quantitative RT-PCR to investigate SUB1A and SUB1C transcripts in relation with submergence tolerance and stem elongation (under submergence). Two F1 hybrids were developed, using three distinct parents: susceptible Fulkari, moderately tolerant Kalukanda and tolerant Swarna-SUB1. The allele-specific transcripts of two genes in tolerant, susceptible and moderately tolerant varieties indicated that differential expression of both SUB1A and SUB1C alleles was associated with different level of tolerance. The results demonstrated that the two hybrids had unequal expression of two alleles indicating nonadditive interaction of alleles with different level of tolerance. Hybrid-1 (Fulkari/Swarna-SUB1) showed lower negative heterosis for SUB1A (-47.8%) and plant survival (-13.9%) and antagonistic interaction of heterozygous combination of two alleles lowered SUB1A expression leading to susceptibility. SUB1 gene-expression in tolerant rice variety Kalukanda and its hybrid (Kalukanda/Swarna-SUB1) showed synergistic action of SUB1A and SUB1C transcripts with higher SUB1A and SUB1C, which is a new observation compared with antagonistic relationship (higher SUB1A and lower SUB1C) reported in tolerant SUB1 gene. With the possibility of different submergence tolerance mechanisms in Kalukanda, its use in hybridization might lead to improvement of submergence tolerance with balanced levels of both SUB1A and SUB1C transcripts. [ABSTRACT FROM AUTHOR]

Although small airways account for the largest fraction of the total conducting airway surfaces, the epithelial fluid and electrolyte transport in small, native airway epithelia has not been well characterized. Investigations have been limited, no doubt, by the complex tissue architecture as well as by its inaccessibility, small dimensions, and lack of applicable assays, especially in human tissues. To better understand how the critically thin layer of airway surface liquid (ASL) is maintained, we applied a "capillary"-Ussing chamber (area ≈1 mm 2 ) to measure ion transport properties of bronchioles with diameters of ~2 mm isolated from resected specimens of excised human lungs. We found that the small human airway, constitutively and concurrently, secretes and absorbs fluid as observed in porcine small airways (50). We found that the human bronchiolar epithelium is also highly anion selective and constitutively secretes bicarbonate ( HCO 3 - ), which can be enhanced pharmacologically by cAMP as well as Ca 2+ -mediated agonists. Concurrent secretion and absorption of surface liquid along with HCO 3 - secretion help explain how the delicate volume of the fluid lining the human small airway is physiologically buffered and maintained in a steady state that avoids desiccating or flooding the small airway with ASL.