116 research outputs found

    Development of EST Derived Microsatellite Markers in Buffel Grass and Their Cross Transferability to Other Forage Grasses

    Get PDF
    Buffel grass (Cenchrus ciliaris L.) is an important perennial grass grown widely in arid and semiarid regions of the world. It is one of the prominent species of the Dichanthium-Cenchrus-Lasiurus grass cover spread over the Peninsular India (Dabadghao and Shankarnarayan, 1973). C. ciliaris is a warm season, C4 grass well adapted to survive harsh conditions, elevated CO2 levels and wide range of climates and soil regimes. It is considered an excellent pasture grass as it provides highly nutritious and palatable forage during drought periods. Despite its excellent forage characteristics genetic improvement through conventional breeding methods has been difficult due to its apomictic mode of reproduction, and is mostly confined to the selection of elite lines from natural variants. (Bhat et al., 2001). Knowledge of genetic diversity and phenetic relationships among accessions is prerequisite for breeding programmes. The study of morphological variability is the only approach for assessing genetic diversity especially in minor crops. An assessment based only on agro-morphological traits might be biased because distinct morphotypes can result from spontaneous mutations. However, with molecular markers, genetic resources can accurately be assessed and characterized (Capo-chichi et al., 2004). Buffel grass has been extensively studied to understand the genetic regulation of apomixis targeting the genomic regions shared and conserved across grass family, while limited studies have been done so far to assess the genetic variation and utilization in breeding for agronomically important traits and absence of adequate genomic resources impeded further improvement. Cenchrus cultivars and accessions have previously been characterized using random amplified polymorphic DNA (RAPD), amplified fragment length polymorphism (AFLP), inter-simple sequence repeat (ISSR) and Sequence tagged site (STS) markers. While microsatellites are the most preferred markers due to their locus specificity, codominant nature, high polymorphism and reproducibility, their development and application is highly time consuming and expensive and has been limited to a few agriculturally important crops (Powell et al., 1996). An alternative way is to search the abundant sequence data already available in public databases to identify SSR’s. Nevertheless, markers developed in this way present a valuable resource for subsequent comparison between the model species and the related species. Therefore, the objectives of the present study were to develop EST based SSR markers and test their transferability potential in other related forage grasses

    Some aspects of hydrobiological study on the shelf waters off Bombay

    Get PDF
    Variations in salinity, temperature, dissolved oxygen and zooplankton biomass in the shelf waters off Bombay where the exploratory fishing vessels were operating, studied for one year from April 1972 to April 1973. Hydrographic features in the locality diowed double oscillations. Zooplankton biomass exhibited two peaks - one immediately before and the other soon after the southwest monsoon, the latter being secondary in nature. List of dominant zooplankters found in the area in various months are given in the order of their abundance

    Lithosphere Structure and upper mantle characteristics below the Bay of Bengal

    No full text
    The oceanic lithosphere in the Bay of Bengal (BOB) formed 80–120 Ma following the breakup of eastern Gondwanaland. Since its formation, it has been affected by the emplacement of two long N-S trending linear aseismic ridges (85oE and Ninetyeast) and by the loading of ca. 20-km of sediments of the Bengal Fan. Here, we present the results of a combined spatial and spectral domain analysis of residual geoid, bathymetry and gravity data constrained by seismic reflection and refraction data. Self-consistent geoid and gravity modeling defined by temperature-dependent mantle densities along a N-S transect in the BOB region revealed that the depth to the Lithosphere-Asthenosphere boundary (LAB) deepens steeply from 77 km in the south to 127 km in north, with the greater thickness being anomalously thick compared to the lithosphere of similar-age beneath the Pacific Ocean. The Geoid-Topography Ratio (GTR) analysis of the 85°E and Ninetyeast ridges indicate that they are compensated at shallow depths. Effective elastic thickness (Te) estimates obtained through admittance/ coherence analysis as well as the flexural modeling along these ridges led to the conclusions: i) 85°E Ridge was emplaced in off-ridge environment (Te = 10–15 km); ii) the higher Te values of ?25 km over the Afanasy Nikitin Seamount (ANS) reflect the secondary emplacement of the seamount peaks in off-ridge environment, iii) that the emplacement of the Ninetyeast Ridge north of 2°N occurred in an off-ridge environment as indicated by higher Te values (25-30 km). Furthermore, the admittance analysis of geoid and bathymetry revealed that the admittance signatures at wavelengths >800 km are compensated by processes related to upper mantle convection

    Establishment of High-Efficiency Agrobacterium-Mediated Transformation of Callus Derived from \u3cem\u3eSehima nervosum\u3c/em\u3e, an Important Range Grass Species

    Get PDF
    Sehima nervosum is one of the important rangeland grass in India, It is commonly known as Saen grass in India, white grass in Australia, and has also been reported from the Central East Africa and Sudan. It is a good forage grass and maybe utilized for grazing as well as for hay preparation. It is a perennial grass, prefers hot and dry climate and survive even in limited rainfalls. As this natural grass is found inherently rich in precursors for several industrially important biomolecules, fractionation of these precursors seems to be a promising endeavour. Production of nutraceuticals (prebiotic xylo-oligosaccharides) from the lignocellulosic biomass of this grass is promising, as this grass does not compete with food crops, and is comparatively less expensive than conventional agricultural food-stocks. However, germplasm of this grass has narrow genetic variability. Being largely apomictic in reproduction, generation of variability through hybridization approaches have been limited. Utilization of biotechnological tools is one of the potential ways for introducing variability and transfer of desirable traits. The development of an efficient genetic transformation procedure for Sehima could facilitate physiological and molecular biology studies as well as the production of transgenic cultivars for higher productivity and quality. To the best of our knowledge there are no reports on in vitro callus induction, regeneration and transformation in Sehima. Herein, for the first time, efficient in vitro callus induction from mature seed explant and transformation efficiency in Sehima is reported. Here we standardized a reproducible, rapid and efficient Agrobacterium mediated transformation using Agrobacterium strain EHA105 harbouring binary vector pCAMBIA 1305

    FisHook -- An Optimized Approach to Marine Specie Classification using MobileNetV2

    Full text link
    Marine ecosystems are vital for the planet's health, but human activities such as climate change, pollution, and overfishing pose a constant threat to marine species. Accurate classification and monitoring of these species can aid in understanding their distribution, population dynamics, and the impact of human activities on them. However, classifying marine species can be challenging due to their vast diversity and the complex underwater environment. With advancements in computer performance and GPU-based computing, deep-learning algorithms can now efficiently classify marine species, making it easier to monitor and manage marine ecosystems. In this paper, we propose an optimization to the MobileNetV2 model to achieve a 99.83% average validation accuracy by highlighting specific guidelines for creating a dataset and augmenting marine species images. This transfer learning algorithm can be deployed successfully on a mobile application for on-site classification at fisheries

    Transcriptome Analysis of Differentially Expressed Genes at Pre-Meiotic Developmental Stage in Pennisetum Hybrids with Contrasting Modes of Reproduction

    Get PDF
    Apomixis is an asexual reproduction through seeds where embryo develops without meiosis and fertilization. It is widely distributed throughout plant kingdom, but is more prevalent in families like Asteraceae, Rosaceae and Poaceae (Carman, 1997). This trait is highly desirable for fixing heterosis in F1 hybrids with significant implications for crop improvement (Dwivedi et al., 2007). Therefore it is necessary to unravel the molecular and genetic basis of apomixis to tap its potential. Pennisetum is an important genus of the Poaceae family which contains a wide range of species exhibiting wide variability in morphological, molecular, and reproductive traits (Jauhar, 1998). It includes many apomictic wild relatives of cultivated pearl millet (Pennisetum glaucum), some of them used extensively for introgression and molecular studies on apomixis, such as P. squamulatum, P. ciliare, and P. orientale (Ozias-Akins and Van Dijk, 2007; Kaushal et al., 2010). In order to identify putative genes involved in expression of apomixis, the genes showing differential expression across sexual and apomictic genotypes may be identified and characterized. A variety of methods are available for such molecular differential screening. These include differential display, fingerprinting techniques like cDNA AFLP, Subtractive hybridization, Micro array and Gene Chip technologies. These methods are employed for different purposes based on their convenience, sensitivity, automation and throughput. Texa with contrasting modes of reproduction are resources to identify genes involved in apomixis phenomenon. Broadly, the differentiation in reproduction pathway between apomictic and sexual lines is at three steps viz. pre-meiotic (including genes involved in preparing of ovule to enter into apomeiotic pathway), meiotic (genes involved in apomeiosis and embryo-sac development) and post-meiotic (genes involved in embryo-sac maturation and preparing for parthenogenesis). The present study was aimed to carry out a comprehensive transcriptome survey to identify differentially expressed transcripts in ovules of aposporous Pennisetum hybrid during the pre-meiotic stage of apomictic reproduction

    RED ALERT ! INFANT VAGINAL BLEEDING

    Get PDF
    Infant vaginal bleeding is an alarming symptom in an infant. Although several causes can be listed, the possibility of malignancy still needs to be ruled out in view of the guarded prognosis of these uncommon infantile tumors. This case report aims to raise the awareness towards the workup and management of infantile malignancies in a baby girl

    Ploidy Dependent Expression of Apomixis Components in Guinea Grass (\u3cem\u3ePanicum maximum\u3c/em\u3e Jacq.)

    Get PDF
    Apomixis is an asexual method of reproduction through seeds. The potential of apomixis has been envisaged as “asexual revolution” by virtue of its capacity to fix hybrid vigour, a much desirable feature in breeding of agricultural crops. The genetic mechanism of apomixis regulation is complex and is believed to be largely affected by polyploidy (Nogler 1984). Expression of apomixis essentially contains three components, viz. apomeiosis (formation of unreduced egg cell), parthenogenesis (fertilization independent embryo development) and functional endosperm development (autonomous or psuedogamous). In contrast to previous reports, the evidence has now gathered that these three components can be functionally uncoupled and recombination is possible between these components (Kaushal, et al., 2008). Such recombinations lead to diversity in seed development pathways and also provide a mechanism to modify the ploidy levels. Uncoupling of apomeiosis from parthenogenesis may yield high frequency of triploids and haploids. Utilizing this partitioning principle we have generated a ploidy series following a Hybridization–supplemented Apomixis-components Partitioning Approach (HAPA) in guinea grass, a model crop for polyploidy and apomixis research, (Kaushal et al., 2009). From a single 4x (2n=32) progenitor, a ploidy series has been developed represented by 3x, 4x, 5x, 6x, 7x, 8x, 9x and 11x cytotypes. This ploidy series offers advantage of studying ploidy regulated gene expression. There have been sporadic reports on effect of polyploidy in expression of apomixis per se; however information on effect of polyploidy on individual apomixis components is not available. The guinea grass ploidy series with sequentially added monoploid genome doses has been used in present study to understand the effect of ploidy levels on phenotypic expression of partitioned apomixis components

    Magnetic anomalies of offshore Krishna-Godavari basin, eastern continental margin of India

    Get PDF
    The marine magnetic data acquired from offshore Krishna-Godavari (K-G) basin, eastern continental margin of India (ECMI), brought out a prominent NE-SW trending feature, which could be explained by a buried structural high formed by volcanic activity. The magnetic anomaly feature is also associated with a distinct negative gravity anomaly similar to the one associated with 85°E Ridge. The gravity low could be attributed to a flexure at the Moho boundary, which could in turn be filled with the volcanic material. Inversion of the magnetic and gravity anomalies was also carried out to establish the similarity of anomalies of the two geological features (structural high on the margin and the 85°E Ridge) and their interpretations. In both cases, the magnetic anomalies were caused dominantly by the magnetization contrast between the volcanic material and the surrounding oceanic crust, whereas the low gravity anomalies are by the flexures of the order of 3-4 km at Moho boundary beneath them. The analysis suggests that both structural high present in offshore Krishna-Godavari basin and the 85°E Ridge have been emplaced on relatively older oceanic crust by a common volcanic process, but at discrete times, and that several of the gravity lows in the Bay of Bengal can be attributed to flexures on the Moho, each created due to the load of volcanic material
    corecore