143 research outputs found

    On the occurrence of Acanthaster planci (the crown-of-thorns) at Minicoy Atoll.

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    The predation of coral-polyps by the multi-armed star fish Acanthaster planci is identified during the last two decades as a major biological factor that causes large scale death to reef corals at several parts of the Indo-Pacific. During a recent visit by a team of scientists from Central Marine Fisheries Research Institute,the presence of this star fish in the lagoon of Minicoy Atoll was noticed in November, 1979.Many control measures of star fishes have been practised elsewhere in the Pacific. However, hand-picking of the adults with the aid of pointed spears and killing them with formalin or ammonia solution is the most eifective.Careful search among the corals is required, since the crown-of-thorns hide under the crevices during day time

    Hydrological features of the Arabian sea off the Northern and central west coast of India During 1964 winter

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    The hydrographic features prevailing along the northern and central west coast of India during the early part of winter 1964 are discussed. A weak northward gradient in temperature north of 17°N and an eastward gradient south of it is noticed. The thermocline is found at shallower depths in the northern regions. A steady increase in the salinity is observed northward, the maximum being off Bombay. North of 17°N the flow is mainly eastwards which deflects towards south with increase in depth. At SO m a continuous weak southward drift is noticed. More or less uniform distribution is foimd in the dissolved oxygen content at surface and 20 m depth, but at 50 m depth eastward gradients are noticed. Sharp decrease in dissolved oxygen values occur from the top of the thermocline and the oxygen minimum layer is conspicuous in all the sections. The nature of the isotherms and the isolines of oxygen indicate the presence of upwelling in the region off Bombay. The total phosphorus content is much less in the region between 15°N and 18°N with higher values further south and north of these latitudes. The patterns of distribution of dissolved oxygen and total phosphorus contents show an inverse relationship. A westward gradient in the phosphorus values is seen at 50 m depth

    Observations on the distribution and seasonal fluctuations of Chaetognaths off Vizhinjam, Southwest coast of India

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    The distribution and seasonal abundance of Chaetognaths belonging to the genera Sagitta Quoy and Gaimard and Ptemagitta Costa collected during the cruises of Cadahin-VI between January and December, 1990 from three sectors off Vizhinjam, on the southwest coast of India, were studied in relation to hydrographic factors. Sagitta urfIata was the most dominant species for the greater part of the year and the present study revealed that this species is a continuous breeder with several peaks of intensive spawning. Species such as Sagitta farox. S. robusta and S. pacifca are recorded only during the premonsoon and later postmonsoon periods

    P Deepa Shenoy and Venugopal KR,“PTMIB: Profiling Top Most Influential Blogger using Content Based Data Mining Approach,”

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    Users of Online Social Network (OSN) communicate with each other, exchange information and spread rapidly influencing others in the network for taking various decisions. Blog sites allow their users to create and publish thoughts on various topics of their interest in the form of blogs/blog documents, catching the attention and letting readers to perform various activities on them. Based on the content of the blog documents posted by the user, they become popular. In this work, a novel method to profile Top Most Influential Blogger (TMIB) is proposed based on content analysis. Content of blog documents of bloggers under consideration in the blog network are compared and analyzed. Term Frequency and Inverse Document Frequency (TF-IDF) of blog documents under consideration are obtained and their Cosine Similarity score is computed. Synonyms are substituted against those unmatched keywords if the Cosine Similarity score so computed is below the threshold and an improved Cosine Similarity score of those documents under consideration is obtained. Computing the Influence Score after Synonym substitution (ISaS) of those bloggers under conflict, the top most influential blogger is profiled. The simulation results demonstrate that the proposed Profiling Top Most Influential Blogger using Synonym Substitution (PTMIBSS) algorithm is adequately accurate in determining the top most influential blogger at any instant of time considered

    Tissue-Specific Transcriptomics of the Exotic Invasive Insect Pest Emerald Ash Borer (Agrilus planipennis)

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    BACKGROUND: The insect midgut and fat body represent major tissue interfaces that deal with several important physiological functions including digestion, detoxification and immune response. The emerald ash borer (Agrilus planipennis), is an exotic invasive insect pest that has killed millions of ash trees (Fraxinus spp.) primarily in the Midwestern United States and Ontario, Canada. However, despite its high impact status little knowledge exists for A. planipennis at the molecular level. METHODOLOGY AND PRINCIPAL FINDINGS: Newer-generation Roche-454 pyrosequencing was used to obtain 126,185 reads for the midgut and 240,848 reads for the fat body, which were assembled into 25,173 and 37,661 high quality expressed sequence tags (ESTs) for the midgut and the fat body of A. planipennis larvae, respectively. Among these ESTs, 36% of the midgut and 38% of the fat body sequences showed similarity to proteins in the GenBank nr database. A high number of the midgut sequences contained chitin-binding peritrophin (248)and trypsin (98) domains; while the fat body sequences showed high occurrence of cytochrome P450s (85) and protein kinase (123) domains. Further, the midgut transcriptome of A. planipennis revealed putative microbial transcripts encoding for cell-wall degrading enzymes such as polygalacturonases and endoglucanases. A significant number of SNPs (137 in midgut and 347 in fat body) and microsatellite loci (317 in midgut and 571 in fat body) were predicted in the A. planipennis transcripts. An initial assessment of cytochrome P450s belonging to various CYP clades revealed distinct expression patterns at the tissue level. CONCLUSIONS AND SIGNIFICANCE: To our knowledge this study is one of the first to illuminate tissue-specific gene expression in an invasive insect of high ecological and economic consequence. These findings will lay the foundation for future gene expression and functional studies in A. planipennis

    Bacterial Gut Symbionts Contribute to Seed Digestion in an Omnivorous Beetle

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    Obligate bacterial symbionts alter the diets of host animals in numerous ways, but the ecological roles of facultative bacterial residents that colonize insect guts remain unclear. Carabid beetles are a common group of beneficial insects appreciated for their ability to consume insect prey and seeds, but the contributions of microbes to diet diversification in this and similar groups of facultative granivores are largely unknown.Using 16S rRNA gene clone libraries and terminal restriction fragment (tRF) length polymorphism analyses of these genes, we examined the bacterial communities within the guts of facultatively granivorous, adult Harpalus pensylvanicus (Carabidae), fed one of five dietary treatments: 1) an untreated Field population, 2) Seeds with antibiotics (seeds were from Chenopodium album), 3) Seeds without antibiotics, 4) Prey with antibiotics (prey were Acheta domesticus eggs), and 5) Prey without antibiotics. The number of seeds and prey consumed by each beetle were recorded following treatment. Harpalus pensylvanicus possessed a fairly simple gut community of approximately 3-4 bacterial operational taxonomic units (OTU) per beetle that were affiliated with the Gammaproteobacteria, Bacilli, Alphaproteobacteria, and Mollicutes. Bacterial communities of the host varied among the diet and antibiotic treatments. The field population and beetles fed seeds without antibiotics had the closest matching bacterial communities, and the communities in the beetles fed antibiotics were more closely related to each other than to those of the beetles that did not receive antibiotics. Antibiotics reduced and altered the bacterial communities found in the beetle guts. Moreover, beetles fed antibiotics ate fewer seeds, and those beetles that harbored the bacterium Enterococcus faecalis consumed more seeds on average than those lacking this symbiont.We conclude that the relationships between the bacterium E. faecalis and this factultative granivore's ability to consume seeds merit further investigation, and that facultative associations with symbiotic bacteria have important implications for the nutritional ecology of their hosts

    Bacterial Communities of Diverse Drosophila Species: Ecological Context of a Host–Microbe Model System

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    Drosophila melanogaster is emerging as an important model of non-pathogenic host–microbe interactions. The genetic and experimental tractability of Drosophila has led to significant gains in our understanding of animal–microbial symbiosis. However, the full implications of these results cannot be appreciated without the knowledge of the microbial communities associated with natural Drosophila populations. In particular, it is not clear whether laboratory cultures can serve as an accurate model of host–microbe interactions that occur in the wild, or those that have occurred over evolutionary time. To fill this gap, we characterized natural bacterial communities associated with 14 species of Drosophila and related genera collected from distant geographic locations. To represent the ecological diversity of Drosophilids, examined species included fruit-, flower-, mushroom-, and cactus-feeders. In parallel, wild host populations were compared to laboratory strains, and controlled experiments were performed to assess the importance of host species and diet in shaping bacterial microbiome composition. We find that Drosophilid flies have taxonomically restricted bacterial communities, with 85% of the natural bacterial microbiome composed of only four bacterial families. The dominant bacterial taxa are widespread and found in many different host species despite the taxonomic, ecological, and geographic diversity of their hosts. Both natural surveys and laboratory experiments indicate that host diet plays a major role in shaping the Drosophila bacterial microbiome. Despite this, the internal bacterial microbiome represents only a highly reduced subset of the external bacterial communities, suggesting that the host exercises some level of control over the bacteria that inhabit its digestive tract. Finally, we show that laboratory strains provide only a limited model of natural host–microbe interactions. Bacterial taxa used in experimental studies are rare or absent in wild Drosophila populations, while the most abundant associates of natural Drosophila populations are rare in the lab
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