Lethal effect of phenothiazine neuroleptics on the pathogenic protozoan Leishmania donovani

Phenothiazine drugs, which are widely used for their antipsychotic, antianxiety, and antiemetic effects, have been found to have protozoacidal effects on the human pathogen Leishmania donovani. These compounds are lethal to both the extracellular stage of the organism, which is inoculated into humans by the sand fly, and the intracellular stage, which is found solely in human macrophages during established infection.     

Effects of surface fire on litter decomposition and occurrence of microfungi in a Cymbopogon polyneuros dominated grassland

Abstract

Litter decomposition rate, changes in macronutrients such as nitrogen (N), phosphorus (P) and potassium (K) from different grades of litter decomposition and occurrence of soil microfungi were investigated in a Cymbopogon polyneuros-dominated tall grass ecosystem from a burned and an unburned site in southern India. The litter decomposition rate was higher at the burned site than at the unburned site. This rate was also higher when the litter was mixed with the mineral soil material than leaving the litter unaffected on the soil surface. The concentrations of N, P, and K in the litter decreased as a result of progressed litter decomposition. Occurrence of microfungi identified from the different decomposition grades of the Cymbopogon polyneuros litter was higher at the burned site compared to the unburned site. Microfungal species present at both sites showed only minor differences.     

Estimation of Leaf Area in Greengram by Non-destructive Linear Measurements

The leaf area by non-destructive linear measurements have been made in eight cultivars of greengram. The regression equation was Y = 1.58 + 1.79 (X), r = 0.9988** while X = L × W. L and W are the maximum length and width of the terminal leaflet of a trifoliate leaf respectively. Y = leaf area of a trifoliate leaf. This study indicated that this equation can be used for a measuring of the leaf area in situ irrespective of the position of the leaves and variety in greengram.

Zusammenfassung

Abschätzung der Blattfläche von Mung-Bohne mit Hilfe einer nichtdestruktiven linearen Messung
Die Untersuchungen zu einer nichtdestruktiven linearen Messung wurden bei acht Sorten der Mung-Bohne durchgeführt. Die Regressionsgleichung war Y = 1,58 + 1,79 (X), r = 0,9988**, während ×= L × W war. L und W sind die Maximumlängen und Breiten des terminalen Blattes eines dreifach gefiederten Blattes. Y = Blattfläche eines dreifach gefiederten Blattes. Die Untersuchung zeigt, daß die Gleichung für die Messung der Blattfläche in situ bei Mungo-Bohnen verwendet werden kann, unabhängig von der Position des Blattes und der Sorte.     

Genetic analysis and validation of quantitative trait loci associated with reproductive-growth traits and grain yield under drought stress in a doubled haploid line population of rice (Oryza sativa L.)

Drought is a major constraint for rice production and yield stability in rainfed ecosystems, especially when it occurs during the reproductive stage. Combined genetic and physiological analysis of reproductive-growth traits and their effects on yield and yield components under drought stress is important for dissecting the biological bases of drought resistance and for rice yield improvement in water-limited environments. A subset of a doubled haploid (DH) line population of CT9993-5-10-1-M/IR62266-42-6-2 was evaluated for variation in plant water status, phenology, reproductive-growth traits, yield and yield components under reproductive-stage drought stress and irrigated (non-stress) conditions in the field. Since this DH line population was previously used in extensive quantitative trait loci (QTLs) mapping of various drought resistance component traits, we aimed at identifying QTLs for specific reproductive-growth and yield traits and also to validate the consensus QTLs identified earlier in these DH lines using meta-analysis. DH lines showed significant variation for plant water status, reproductive-growth traits, yield and yield components under drought stress. Total dry matter, number of panicles per plant, harvest index, panicle harvest index, panicle fertility, pollen fertility, spikelet fertility and hundred grain weight had significant positive correlations with grain yield under drought stress. A total of 46 QTLs were identified for the various traits under stress and non-stress conditions with phenotypic effect ranging from 9.5 to 35.6% in this study. QTLs for panicle exsertion, peduncle length and pollen fertility, identified for the first time in this study, could be useful in marker-assisted breeding (MAB) for drought resistance in rice. A total of 97 QTLs linked to plant growth, phenology, reproductive-growth traits, yield and its components under non-stress and drought stress, identified in this study as well as from earlier published information, were subjected to meta-analysis. Meta-analysis identified 23 MQTLs linked to plant phenology and production traits under stress conditions. Among them, four MQTLs viz., 1.3 for plant height, 3.1 for days to flowering, 8.1 for days to flowering or delay in flowering and 9.1 for days to flowering are true QTLs. Consensus QTLs for reproductive-growth traits and grain yield under drought stress have been identified on chromosomes 1 and 9 using meta-QTL analysis in these DH lines. These MQTLs associated with reproductive-growth, grain yield and its component traits under drought stress could be useful targets for drought resistance improvement in rice through MAB and/or map-based positional analysis of candidate genes.     

Diversity of Sodium Transporter HKT1;5 in Genus Oryza

Asian cultivated rice shows allelic variation in sodium transporter, OsHKT1;5, correlating with shoot sodium exclusion (salinity tolerance). These changes map to intra/extracellularly-oriented loops that occur between four transmembrane-P loop-transmembrane (MPM) motifs in OsHKT1;5. HKT1;5 sequences from more recently evolved Oryza species (O. sativa/O. officinalis complex species) contain two expansions that involve two intracellularly oriented loops/helical regions between MPM domains, potentially governing transport characteristics, while more ancestral HKT1;5 sequences have shorter intracellular loops. We compared homology models for homoeologous OcHKT1;5-K and OcHKT1;5-L from halophytic O. coarctata to identify complementary amino acid residues in OcHKT1;5-L that potentially enhance affinity for Na⁺. Using haplotyping, we showed that Asian cultivated rice accessions only have a fraction of HKT1;5 diversity available in progenitor wild rice species (O. nivara and O. rufipogon). Progenitor HKT1;5 haplotypes can thus be used as novel potential donors for enhancing cultivated rice salinity tolerance. Within Asian rice accessions, 10 non-synonymous HKT1;5 haplotypic groups occur. More HKT1;5 haplotypic diversities occur in cultivated indica gene pool compared to japonica. Predominant Haplotypes 2 and 10 occur in mutually exclusive japonica and indica groups, corresponding to haplotypes in O. sativa salt-sensitive and salt-tolerant landraces, respectively. This distinct haplotype partitioning may have originated in separate ancestral gene pools of indica and japonica, or from different haplotypes selected during domestication. Predominance of specific HKT1;5 haplotypes within the 3 000 rice dataset may relate to eco-physiological fitness in specific geo-climatic and/or edaphic contexts.     

Vesicular-arbuscular mycorrhizae in tropical sedges of southern India

Twenty-four species of sedges (representing six genera) from different vegetation types in Western Ghats, South India, were examined for vesicular-arbuscular mycorrhizal (VAM) associations. All the sedges had VAM fungal infections with hyphae and vesicles, but arbuscules were observed only in 42% of the total species. The VAM fungal colonization varied considerably between species, ranging from 9 to 62%. Root colonization was positively and negatively correlated with root diameter and root hair length, respectively. The number of VAM fungal spores in the rhizosphere varied from 5 to 86 g^-1 soil. No significant relationship was found between spore numbers or root colonization and either soil pH or moisture. Four Glomus spp., one Acaulospora sp., one Sclerocystis spp., and one Gigaspora sp. were identified among the VAM fungal spores. The results reflect a high incidence of VAM in sedges occurring in Western Ghats and emphasize the need to assess the VAM status of plant species from different ecosystems to understand their mycorrhizal status.     

Certain factors associated with blister blight resistance in Camellia sinensis (L.) O. Kuntze

The role played by certain factors, physical barriers and chitinase enzyme, associated with blister blight resistance in tea was investigated. The blister blight resistance of the tea clone SA-6 was due to higher amounts of epicuticular wax and increased thickness of cuticle/epidermal layer, functioning as physical barriers to hyphal penetration of Exobasidium vexans. Higher quantum of chitinase in intercellular spaces of palisade tissues was observed in the resistant clone SA-6 through immunolocalization study. Both chitinase assay as well as western blotting studies confirmed that the constitutive level of chitinase expression was higher in the resistant clone when compared with the susceptible tea clone.     

Selection Index for High Density Grain in Rice to Maximize Productivity

A study conducted on five rice varieties indicated that productivity can be enhanced from 17 to 29 % by increasing the number of high density (HD) grains/panicle. HD grains/panicle were partitioned into different components. The number of secondary branches/panicle and the number of HD grains on secondary branches were identified as the most important contributing factors for the number of HD grains/panicle. Selection of plants with panicles having these characters would increase the proportion of HD grains/panicle and productivity.     

Prolonging Seed Viability in Groundnut (Arachis hypogaea L.) with Calcium Chloride

Groundnut pods stored in gunny bags, polythene lined gunny bags, polythene lined gunny bags with fused CaCl₂, mud pots, and bamboo baskets showed significant differences in germination and vigour. The increased viability of pods in polythene lined gunny bag with fused CaCl₂ is attributed to low moisture content and high dehydrogenase activity. The present study showed that the viability of groundnut pods could be enhanced using desiccant like fused Calcium Chloride.