Determination of Mitotic Index and Evaluation of Cytogenotoxicity of Oxyfluorfen Using Allium Cepa Root Tip Meristematic Cells

The present study aimed to investigate Oxyfluorfen induced cytogenotoxicity employing Allium cepa meristematic cells as test models. The root length inhibition was determined exposing the meristematic cells to eleven Oxyfluorfen concentrations such as 0.01, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9ppm and 1ppm against controls and the inhibition was statistically (p<0.05) significant at 0.2, 0.3, 0.4, 0.7, 0.8, 0.9 and 1ppm and insignificant for the rest. The root length was drastically reduced at 0.3ppm and complete at 1ppm. The significant change in cell shape and structure was observed at 0.4 & 0.5ppm when compared to 0.01 & 0.1ppm. The mitotic index was calculated considering interphase, prophase, metaphase, anaphase and telophase as cell cycle stages out of one thousand cells. The per cent mitotic index of 0.01, 0.1, 0.2, 0.3, 0.4ppm and 0.5ppm concentrations was found to be 49, 32.8, 29.4, 0, 32.8 and 51.4 respectively and this result significantly correlates with root length inhibition studies. Cell cycle check points will block or delay the progression of mitosis due to pesticide interference with mitotic phase duration, making some phases more frequent than others. Therefore, it is established that Oxyfluorfen is cytogenotoxic to Allium cepa meristematic cells and this technique is very convenient to assess how toxic substances bring abnormality at cell and organelles level

SIMULTANEOUS DETERMINATION OF ARTESUNATE AND AMODIAQUINE IN HUMAN PLASMA USING LC-MS/MS AND ITS APPLICATION TO A PHARMACOKINETIC STUDY

Objective: The objective of this research was to develop a simple, rapid and sensitive liquid chromatography/tandem mass spectrometry (LC-MS/MS) method for the simultaneous quantification of artesunate and amodiaquine in human plasma.Methods: An analytical method based on LC-MS/MS has been developed and validated for the simultaneous determination of artesunate and amodiaquine in human plasma. Isotope-labeled compounds are used as internal standards for the quantification of these drugs. Analytes were extracted from the plasma using solid phase extraction (SPE) technique and chromatographed on a C8 column using an isocratic mobile phase composed of 0.1% ammonia solution and methanol (10:90, v/v). The mobile phase was pumped at a flow rate of 1.00 ml/min. A total of five analytical batches were generated for the calculation of intra-day and inter-day precision and accuracy during the entire course of validation.Results: The assay exhibits excellent linearity in the concentration range of 3.07–305.29 ng/ml for artesunate and 0.30–30.01 ng/ml for amodiaquine. Intra-day and inter-day precision and accuracy results are well within the acceptance limits. All the stability experiments were conducted in plasma samples and in neat samples are complying with the recent US FDA and EMEA guidelines.Conclusion: The proposed LC–MS/MS assay method is simple, rapid and sensitive enough for the simultaneous determination of artesunate and amodiaquine in human plasma. This method was successfully used to quantitate the in-vivo plasma concentrations obtained from a pharmacokinetic study and the results were validated by conducting incurred samples reanalysis (ISR).Â

Identification of several small main-effect QTLs and a large number of epistatic QTLs for drought tolerance related traits in groundnut (Arachishypogaea L.)

Cultivated groundnut or peanut (Arachis hypogaea L.), an allotetraploid (2n = 4x = 40), is a self pollinated and widely grown crop in the semi-arid regions of the world. Improvement of drought tolerance is an important area of research for groundnut breeding programmes. Therefore, for the identification of candidate QTLs for drought tolerance, a comprehensive and refined genetic map containing 191 SSR loci based on a single mapping population (TAG 24 × ICGV 86031), segregating for drought and surrogate traits was developed. Genotyping data and phenotyping data collected for more than ten drought related traits in 2–3 seasons were analyzed in detail for identification of main effect QTLs (M-QTLs) and epistatic QTLs (E-QTLs) using QTL Cartographer, QTLNetwork and Genotype Matrix Mapping (GMM) programmes. A total of 105 M-QTLs with 3.48–33.36% phenotypic variation explained (PVE) were identified using QTL Cartographer, while only 65 M-QTLs with 1.3–15.01% PVE were identified using QTLNetwork. A total of 53 M-QTLs were such which were identified using both programmes. On the other hand, GMM identified 186 (8.54–44.72% PVE) and 63 (7.11–21.13% PVE), three and two loci interactions, whereas only 8 E-QTL interactions with 1.7–8.34% PVE were identified through QTLNetwork. Interestingly a number of co-localized QTLs controlling 2–9 traits were also identified. The identification of few major, many minor M-QTLs and QTL × QTL interactions during the present study confirmed the complex and quantitative nature of drought tolerance in groundnut. This study suggests deployment of modern approaches like marker-assisted recurrent selection or genomic selection instead of marker-assisted backcrossing approach for breeding for drought tolerance in groundnut

Development and Characterization of Elite Doubled Haploid Lines from Two Indica Rice Hybrids

Despite significant yield advantage over inbred rice, the adoption rate of hybrid rice in India is very low due to the high seed cost and poor quality of the produce. To alleviate the problem, we initiated a doubled haploid (DH) breeding approach to develop new lines from two elite indica rice hybrids (CRHR5 and CRHR7) through rapid fixation of homozygosity in the recombinants. In vitro culture of the rice anthers resulted in 243 and 186 fertile DH lines of CRHR5 and CRHR7, respectively. Flow cytometric and pollen fertility analyses confirmed the DH ploidy status of the regenerations. Morpho-agronomic evaluation revealed 100% uniformity and stability for all the characters in the DH lines of both hybrids. Nineteen promising DH lines of each hybrid were advanced to A2 generation for yield evaluation. The yield levels of the DH lines ranged from 5 097–6 965 kg/hm2 for CRHR5 and 5 141–7 235 kg/hm2 for CRHR7, which were at par or higher than the parental hybrids. Physico-chemical characterization and cooking quality analyses revealed significant and acceptable values for grain length and width, alkali spreading value, amylose content and water uptake ratio of the selected DH lines. Three DH lines, CR5-10, CR5-49, CR5-61 from CRHR5, and four DH lines, CR7-5, CR7-7, CR7-12 and CR7-52 from CRHR7, showed significant grain yield and quality characteristics and have been recommended for multi-location trials for subsequent release as new indica doubled haploid rice varieties