Interaction of curcumin with phosphatidylcholine: A spectrofluorometric study

Curcumin [1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3, 5-dione], the main constituent of the rhizomes of the plant Curcume longa L. (turmeric), is a powerful antioxidant in both enzymatic and nonenzymatic systems. The interactions of curcumin with egg and soy phosphatidylcholine were followed by fluorescence spectroscopy. Curcumin had very weak fluorescence in aqueous system, which was enhanced in apolar environments. Curcumin emitted at 490 nm after being excited at 451 nm in phosphatidylcholine micelles. The equilibrium constants for the interaction of curcumin with egg and soy phosphatidylcholine were (3.26 +/- 0.2) x 10(5) and (2.64 +/- 0.2) x 10(5) M(-1), respectively. From the Scatchard plot of the fluorometric data, it was inferred that one molecule of curcumin could bind six molecules of phosphatidylcholine. The equilibrium constant for the phosphatidylcholine-curcumin interaction decreased with temperature, indicating the amphiphilic nature of curcumin. The DeltaG, DeltaH, and DeltaS values obtained for the interaction of egg phosphatidylcholine-curcumin were -7.8 +/- 0.3 kcal/mol, -9.6 +/- 0.4 kcal/mol, and -6.8 +/- 0.2 cal/mol/K, respectively. The fluorescence anisotropy measurements of curcumin with phosphatidylcholine suggested that the anisotropy of the curcumin molecule did not change in phosphatidylcholine. The interaction of divalent metal ions with phosphatidylcholine-curcumin in comparison with phosphatidylcholine-1-anilino-8-naphathalenesulfonic acid complex suggested the strong binding of curcumin to metal ions.     

Effect of biocontrol agents and biofertilizers on root rot,yield, harvest index and nutrient uptake of cassava (Manihot esculanta Crantz)

Cassava is an important subsidiary food and industrial raw material in the tropics. Root rot disease, caused by Phytophthora palmivora, poses a serious threat to cassava cultivation in Tamil Nadu, India. Field experiments (2008–09) were conducted to study the effect of biocontrol agents (Trichoderma spp. and Pseudomonas fluorescens) and biofertilizers (Azospirillum, vesicular–arbuscular mycorrhizal fungi and phosphorus-solubilizing bacteria) on root rot, yield, harvest index and nutrient uptake of cassava at two NPK rates. The design of the experiment was a split plot with two NPK rates, recommended and 50% recommended rate, as the main plot treatments and five biocontrol agents and biofertilizers as subplot treatments. The results clearly indicated that use of a bioinoculants consortium significantly reduced root rot infection/disease incidence over uninoculated controls. Azospirillum significantly improved the yield of cassava at 50% of the recommended rate of NPK. NPK rates had no significant impact on harvest index of cassava and Trichoderma and vesicular–arbuscular mycorrhizal fungi resulted in a higher harvest index even at 50% of the recommended NPK rate. Nitrogen, phosphorus and potassium uptake was significantly improved when treated with biofertilizers and/or a consortium.     

Identification and pathogenicity study of emerging fish pathogens Acinetobacter junii and Acinetobacter pittii recovered from a disease outbreak in Labeo catla (Hamilton, 1822) and Hypophthalmichthys molitrix (Valenciennes, 1844) of freshwater wetland in West Bengal,India

The disease outbreaks in aquaculture system of wetlands are the major cause of fish mortality. Among various bacterial septicaemic diseases, fish mortality caused by Acinetobacter spp. is recently reported in different fish species. Fish disease outbreak was investigated in a wetland of West Bengal, India to identify the aetiological factors involved. The moribund fish were examined and subjected to bacterial isolation. Two bacterial causative agents were identified as Acinetobacter junii and Acinetobacter pittii by biochemical characterization and 16S rRNA gene amplification. Both the isolates were oxidase‐negative, nitrate‐negative, catalase‐positive and indole‐negative. The molecular identification using 16S rRNA gene sequencing and phylogenetic tree analysis further confirmed the two Acinetobacter spp. with 97%–99% similarity. The antibiotic resistance patterns of these two bacteria revealed that both of them were resistant to β‐lactam, cefalexin, cephalothin, amoxyclav, cefuroxime, cefadroxil, clindamycin, vancomycin and penicillin. In addition, A. pittii was also resistant to other antibiotics of cephams group such as ceftazidime and cefotaxime. In the challenge experiment, both A. junii and A. pittii were found to be pathogenic with LD₅₀ of 1.24 × 10⁵ and 1.88 × 10⁷ cfu/fish respectively. Histopathological examination of gill, liver and kidney revealed prominent changes supporting bacterial septicaemia. The investigation reports for the first time on concurrent infection by A. junii and multidrug‐resistant (MDR)‐A. pittii as emerging fish pathogens to cause severe mortality in Labeo catla and Hypophthalmichthys molitrix in a freshwater wetland.     

Prediction of soil depth using environmental variables in an anthropogenic landscape, a case study in the Western Ghats of Kerala, India

Soil (regolith) depth is a crucial input for modeling earth surface phenomena. However, most studies ignore its spatial variability. Techniques that map the spatial variability of soil depth are of three types: (1) physically-based; (2) empirico-statistical from environmental correlates; and (3) interpolation from point observations. In an anthropogenic landscape, soil depth does not depend primarily on natural processes, making it difficult to apply a physically-based approach. The present study compares empirico-statistical methods with geostatistical methods for predicting soil depth in such a landscape: Aruvikkal catchment (9.5 km²) in the Western Ghats of Kerala, India. Regression kriging applied on blocks of 20 m by 20 m using the environmental covariates elevation, slope, aspect, curvature, wetness index, land use and distance from streams, proved to be the best predictor of soil depth. This model explains 52% of the variability of soil depth in the catchment; with a prediction variance of 0.05 to 0.19. A Gaussian simulation was attempted for a more realistic visualization of the depth, as opposed to the smooth kriging prediction. The most important explanatory variable of soil depth in this landscape is land use, as expected from the strong human intervention.     

Rhizobacteria‐mediated resistance against the blackeye cowpea mosaic strain of bean common mosaic virus in cowpea (Vigna unguiculata)

BACKGROUND: The present study investigated the effect of seven Bacillus‐species plant‐growth‐promoting rhizobacteria (PGPR) seed treatments on the induction of disease resistance in cowpea against mosaic disease caused by the blackeye cowpea mosaic strain of bean common mosaic virus (BCMV). RESULTS: Initially, although all PGPR strains recorded significant enhancement of seed germination and seedling vigour, GBO3 and T4 strains were very promising. In general, all strains gave reduced BCMV incidence compared with the non‐bacterised control, both under screen‐house and under field conditions. Cowpea seeds treated with Bacillus pumilus (T4) and Bacillus subtilis (GBO3) strains offered protection of 42 and 41% against BCMV under screen‐house conditions. Under field conditions, strain GBO3 offered 34% protection against BCMV. The protection offered by PGPR strains against BCMV was evaluated by indirect enzyme‐linked immunosorbent assay (ELISA), with lowest immunoreactive values recorded in cowpea seeds treated with strains GBO3 and T4 in comparison with the non‐bacterised control. In addition, it was observed that strain combination worked better in inducing resistance than individual strains. Cowpea seeds treated with a combination of strains GBO3 + T4 registered the highest protection against BCMV. CONCLUSION: PGPR strains were effective in protecting cowpea plants against BCMV under both screen‐house and field conditions by inducing resistance against the virus. Thus, it is proposed that PGPR strains, particularly GBO3, could be potential inducers against BCMV and growth enhancers in cowpea. Copyright © 2009 Society of Chemical Industry     

Traditional versus improved agroforestry systems in Vietnam: a comparison

Combined with the diverse biophysical and social heterogeneity encountered in the northern mountains, the socioeconomic changes in Vietnam that accompanied the decollectivisation process led to complex agrarian dynamics that today challenge traditional farming and management of natural resources. Data for this study were collected from villages in and around Ba Be National Park (BNP) in the Bac Kan Province located in the northern mountains of Vietnam. Traditional slash and burn cultivation is no longer a sustainable practice in Vietnam. The main challenges in the region are to protect biodiversity, maintain the land productivity and simultaneously support local livelihoods. The study shows that improved agroforestry cultivation could provide significantly higher productivity and income per unit of land, besides decreasing pressure on natural forests. The challenge to protect biodiversity is not met, as improved agroforestry implies less tree species. From an institutional and socio‐economic perspective, it is not easy for local communities to readily adapt to improved agroforestry. New systems must be tailored site‐specific to the diverse local conditions of resource‐poor farmers. Copyright © 2006 John Wiley & Sons, Ltd.     

High-level expression of SAG1 and GRA7 gene of Toxoplasma gondii (Izatnagar isolate) and their application in serodiagnosis of goat toxoplasmosis

Toxoplasmosis, caused by Toxoplasma gondii, is a disease of economic importance in livestock, especially in sheep and goats, where it causes abortion. Although several serological tests are in use for diagnosis of infection, production of reliable reagents is a constraint. An 814 bp sequence coding for a truncated surface antigen surface antigen 1 (SAG1), a tachyzoite stage-specific protein, as well as a 657 bp sequence coding for granule protein 7 (GRA7), a dense granule protein were PCR amplified from the genomic DNA of T. gondii. The amplified products were ligated in pET-32b(+) and pET-32c(+) expression vectors, respectively and subsequently transformed into BL21(DE3)pLysS cells. A high-level expression of the histidine-tagged SAG1 and GRA7 fusion proteins were obtained after 7h of incubation. The recombinant proteins were purified using Ni-NTA column and were characterized by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and western blot analysis using reference positive sera from goat, rabbit and humans at 1:100 dilution. Subsequently, the diagnostic efficiency of the recombinant proteins, either individually or as a cocktail of the recombinant proteins, was assessed with 56 reference goat sera by enzyme-linked immunosorbent assay (ELISA). The immunoreactivity of the refolded SAG1 and GRA7 was evidenced by high OD values. The reactivity of the recombinant proteins as a cocktail preparation was more than that of individual proteins in ELISA and could detect accurately the infection in goats. This is the first report of serological detection of caprine toxoplasmosis by ELISA using a cocktail of recombinant Toxoplasma proteins.     

Genetics of resistance to Sesamia inferens infestation and its correlation with yield in maize

Sesamia inferens (Walker) causes 25.7–78.9% losses in maize production in South and South‐East Asia. The genetic basis of host plant resistance is the prerequisite for resistance breeding. Twenty‐four populations derived from S. inferens resistant × susceptible inbreds were used to study the genetic regulation of resistance to S. inferens in maize, to determine the importance of genetic effects through generation mean analysis (GMA) and to understand correlation between resistance and yield. Resistant and susceptible inbreds differed significantly in leaf and stem injury ratings (LSIR), a measure of host plant resistance. Mean LSIR range among resistant and susceptible parents was 2.15–2.55 and 7.83–8.22, respectively. The broad‐sense heritability ranged from 0.40 to 0.71, and the mean number of effective factors ranged from 1.9 to 2.6. The resistance against S. inferens was largely governed by additive × additive (i), followed by dominance (d) and additive (a) gene effects. Significant negative correlation (?0.27 to ?0.96) was observed between LSIR and yield. The findings suggest reciprocal recurrent selection for development of new inbreds with resistance followed by their involvement in hybrid development to exploit additive and non‐additive gene effects/variance.     

Ethnobotanical flora used by four major tribes of Koraput, Odisha, India

The aim of this study is to chronicle the utilization pattern of a number of plant species by four major tribes inhabiting in Koraput district of Odisha, India. Fifteen villages dominated by tribal communities, under five Community Development Blocks were selected. A semi structured questionnaire was developed to bring together data on traditional crops and forest species still used by the communities. The methodology engaged was personal discussions with mixed focused groups combined with field visits, photographs, voice recordings and collection of materials. Findings were that tribal communities cultivate a diverse crop species with varying durations to meet their food and economic requirement throughout the year. This was supplemented by wild food collections during scarcity periods. Various forest species provide wood, fibre, leaves and grasses for agriculture, house construction and specific uses besides enhancing household income. Tribal health care practitioners collect medicinal plants from the wild and semi wild to treat both humans and livestock. At the end of the study the team assumed that tribal communities would continue to depend on traditional crops and wild forest foods for their household consumption and a diverse species of plants for other specific use. Conservation of these valuable resources in its natural habitat would be an appropriate approach for ensuring food security of future generations. Conventional plant breeders and biotechnologists should undertake scientific validation of these crops and plants to make their value explicitly known. This knowledge could be utilized for crop improvement and bio-prospecting. There is also scope for equitable sharing of benefits if used by the seed and pharmaceutical industries in future.