Virulence of Phytophthora isolates from Piper nigrum L. and their sensitivity to metalaxyl-mancozeb

Foot rot disease caused by Phytophthora capsici in black pepper is the most destructive disease. A total of 82 isolates from the National Repository of Phytophthora at ICAR-Indian Institute of Spices Research were evaluated for their sensitivity to metalaxylmancozeb and also tested for their virulence. Of the 82 isolates studied, 19 (23.2%) were highly sensitive to metalaxyl-mancozeb and six (7.3%) were comparatively insensitive (EC90 value >40 ppm; range 41.3 to 68.5 ppm). The isolates also varied in the degree of virulence, viz., 34 (41.5%) were highly virulent, 39 (47.6%) moderately virulent, 4 (3.7%) mildly virulent, and 5 (6.1%) non-virulent. There was neither any significant correlation between sensitivity to metalaxyl-mancozeb and virulence nor with the geographical location.Â

Contribution towards the development of a DNA barcode reference library for West African mammals

DNA barcoding is a widely used molecular approach for species cataloging for unambiguous identification and conservation. In the present study, DNA barcoding of some West African mammals were performed with six new mitochondrial CO1 sequences for Civettictis civetta, Tadarida nigeriae, Orycteropus afer, Heliosciurus gambianus, Equus africanus asinus and Funisciurus anerythrus which are absent in public databases such as BLAST/NCBI and BOLD. Sequence identifications were made by comparing unknown sequences against the DNA barcodes of known species through distance-based tree construction and alignment probing. The sequences have been deposited to GenBank/NCBI.Keywords: mtDNA, West African mammals, conservation, biodiversity

Cross species amplification of microsatellite loci from Phytophthora spp to assess genetic diversity among the Phytophthora isolates from black pepper

Phytophthora capsici is one of the most destructive pathogens of black pepper in India and the world over. Diversity of 114 Phytophthora isolates obtained from leaf, stem, root and soil of different agro climatic areas was studied using 25 SSR primers that were previously described. twenty primers were successfully amplified. Of these, 15 were polymorphic among the Phytophthora isolates and altogether 37 loci were detected. Of the 37 bands generated from 20 primers, 75.67% were polymorphic. Cluster analysis using the unweighted pair-group method with arithmetic averages divided the isolates into seven major groups. The dendrogram generated showed that all the isolates were separated at similarity coefficient between 57-95%. Group 7 with a single isolate stood as an out group. Clustering did not follow the pattern of geographical origin or plant part from where the isolates were obtained. &nbsp

The Prehistoric Indian Ayurvedic Rice Shashtika Is an Extant Early Domesticate With a Distinct Selection History

Fully domesticated rice is considered to have emerged in India at approximately 2000 B.C., although its origin in India remains a contentious issue. The fast-growing 60-days rice strain described in the Vedic literature (1900–500 B.C.) and termed Shashtika (Sanskrit) or Njavara (Dravidian etymology) in Ayurveda texts including the seminal texts Charaka Samhita and Sushruta Samhita (circa 660–1000 B.C.) is a reliable extant strain among the numerous strains described in the Ayurveda literature. We here report the results of the phylogenetic analysis of Njavara accessions in relation to the cultivars belonging to the known ancestral sub-groups indica, japonica, aromatic, and aus in rice gene pool and the populations of the progenitor species Oryza rufipogon using genetic and gene genealogical methods. Based on neutral microsatellite markers, Njavara produced a major clade, which comprised of minor clades corresponding to the genotypic classes reported in Njavara germplasm, and was distinct from that were produced by the ancestral sub-groups. Further we performed a phylogenetic analysis using the combined sequence of 19 unlinked EST-based sequence tagged site (STS) loci with proven potential in inferring rice phylogeny. In the phylogenetic tree also the Njavara genotypic classes were clearly separated from the ancestral sub-groups. For most loci the genealogical analysis produced a high frequency central haplotype shared among most of the rice samples analyzed in the study including Njavara and a set of O. rufipogon accessions. The haplotypes sharing pattern with the progenitor O. rufipogon suggests a Central India–Southeast Asia origin for Njavara. Results signify that Njavara is genetically distinct in relation to the known ancestral sub-groups in rice. Further, from the phylogenetic features together with the reported morphological characteristics, it is likely that Njavara is an extant early domesticate in Indian rice gene pool, preserved in pure form over millennia by the traditional prudence in on-farm selection using 60-days maturity, because of its medicinal applications

ANTIOXIDANT AND ANTIHEMOLYTIC ACTIVITY OF AN ENDANGERED PLANT SPECIES, HILDEGARDIA POPULIFOLIA (ROXB.) SCHOTT & ENDL.

Objective: The present study was aimed at to estimate total content of ascorbic acid, saponins and condensed tannins and to evaluate the antioxidant activity and antihemolytic activity of methanolic extracts of leaf and stem bark parts of Hildegardia populifolia. Methods: Antioxidant activity was carried out by studying nitric oxide scavenging activity, inhibition of β – carotene bleaching activity and antihemolytic activity also studied. Results: Higher amount of ascorbic acid (93.47 g AA/100 g extract), saponins (18.81 g DE/100g extract) and condensed tannins (0.70 mg LE/g dry sample) was observed in methanolic leaf extract than that of the stem bark extract. Nitric oxide scavenging and β – carotene bleaching activity were relatively higher in stem bark extract (IC50 -122.60 and 56.67percent respectively). Leaf extract has higher percentage of antihemolytic activity than that of the stem bark extract.  Conclusion: The results of the study confirmed that the studied plant might indeed be potential sources of natural antioxidant and antihemolytic agents.Key words: Antioxidant, antihemolytic activity, Hildegardia populifolia

Production of PAH cations with narrow internal energy distribution using single nanosecond pulsed laser

The internal energy dynamics of three examples of PAHs are probed using a high resolution energy time of flight spectrometer. The measured H-loss rates are converted to internal energy values for a range of UV photon wavelengths. Multi step multi photon absorption scheme is proposed to estimate the possible internal energy values with reasonable accuracies. This was possible because of the ultrafast radiationless internal conversion process in PAHs and their structural rigidity. Thus, a method is proposed to produce PAH cations with narrow and known internal energy distribution using a single nanosecond pulsed laser, paving a way to study statistical unimolecular decay in PAHs very efficiently

Synthesis, growth, structural, optical and electrical properties of novel organic single crystal: p-toluidinium salicylate

A novel organic single crystal of p-toluidinium salicylate (PTSA) was grown by slow evaporation solution growth technique. The structure of grown crystal was determined from the single crystal X-ray diffraction analysis. The functional groups existing in PTSA crystal were accomplished by using Fourier transform infrared analysis. The optical transparency and band gap energy were estimated by utilizing the UV-Visible spectrum. Photoluminescence spectral studies revealed the photon excitation. The dielectric behavior of PTSA was investigated for different frequencies in a room temperature (308 K) environment. Third-order nonlinear optical susceptibility (χ3) of PTSA crystal was elucidated by Z-scan measurements

The effect of povidone-iodine and chlorhexidine mouth rinses on plaque <i> Streptococcus mutans</i> count in 6- to 12-year-old school children: An <i> in vivo</i> study

Objectives: Treating a carious tooth in children with high caries experience by providing a restoration does not cure the disease. If the unfavorable oral environment that caused the cavity persists so will the disease and more restorations will be required in future. Treating the oral infection by reducing the number of cariogenic microorganisms and establishing a favorable oral environment to promote predominantly remineralization of tooth structure over time will stop the caries process. The present study was conducted: (1) To evaluate the efficacy of povidone-iodine and chlorhexidine mouth rinses on plaque Streptococcus mutans when used as an adjunct to restoration. (2) To compare the anti-microbial effect of 1&#x0025; povidone-iodine and 0.2&#x0025; chlorhexidine mouth rinses on plaque S. mutans count. Study Design: Forty-five study participants in the age group of 6-12 years with dmft (decay component) of three or four were selected from one government school in Bangalore city. They were divided into three groups after the restorative treatment. Group-A, Group-B, and Group-C received 1&#x0025; povidone-iodine mouth rinse, 0.2&#x0025; chlorhexidine mouth rinse and placebo mouth rinse, respectively, twice daily for 14 days. The plaque sample was collected and S. mutans count was estimated at six phases: (1) Baseline, (2) 3 weeks after restoration, (3) First day after mouth rinse therapy, (4) 15 days after mouth rinse therapy, (5) 1 month and (6) 3 months after mouth rinse therapy Results: After the restoration the percentage change in S. mutans count was 28.4&#x0025;. Immediately after mouth rinse therapy there was significant reduction in S. mutans count in all the three groups. After which the count started to increase gradually and after 3 months the bacterial counts in the povidone-iodine group and placebo group were almost near the postrestorative count. Conclusion: Mouth rinses can be used as adjunct to restoration for short duration as temporary measure in reduction of S. mutans count and restorations provide longer effect. In case a mouth rinse has to be used, chlorhexidine can be recommended as it has shown to have better effect than Povidone-iodine and placebo

The AraC/XylS Family Activator RhaS Negatively Autoregulates rhaSR Expression by Preventing Cyclic AMP Receptor Protein Activation▿

The Escherichia coli RhaR protein activates expression of the rhaSR operon in the presence of its effector, l-rhamnose. The resulting RhaS protein (plus l-rhamnose) activates expression of the l-rhamnose catabolic and transport operons, rhaBAD and rhaT, respectively. Here, we further investigated our previous finding that rhaS deletion resulted in a threefold increase in rhaSR promoter activity, suggesting RhaS negative autoregulation of rhaSR. We found that RhaS autoregulation required the cyclic AMP receptor protein (CRP) binding site at rhaSR and that RhaS was able to bind to the RhaR binding site at rhaSR. In contrast to the expected repression, we found that in the absence of both RhaR and the CRP binding site at the rhaSR promoter, RhaS activated expression to a level comparable with RhaR activation of the same promoter. However, when the promoter included the RhaR and CRP binding sites, the level of activation by RhaS and CRP was much lower than that by RhaR and CRP, suggesting that CRP could not fully coactivate with RhaS. Taken together, our results indicate that RhaS negative autoregulation involves RhaS competition with RhaR for binding to the RhaR binding site at rhaSR. Although RhaS and RhaR activate rhaSR transcription to similar levels, CRP cannot effectively coactivate with RhaS. Therefore, once RhaS reaches a relatively high protein concentration, presumably sufficient to saturate the RhaS-activated promoters, there will be a decrease in rhaSR transcription. We propose a model in which differential DNA bending by RhaS and RhaR may be the basis for the difference in CRP coactivation