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Cannanore, India

Raghavan R.,Kerala University of Fisheries and Ocean Studies | Philip S.,Nirmalagiri College | Ali A.,Kerala University of Fisheries and Ocean Studies | Katwate U.,Bombay Natural History Society BNHS | Dahanukar N.,Indian Institute of Science
Reviews in Fish Biology and Fisheries

We summarize the research on Asian Sun catfish, Horabagrus brachysoma (Günther), an endemic and threatened freshwater catfish from Western Ghats of India, and provide a comprehensive review of its taxonomy, distribution, biology, population, conservation and aquaculture. Although described in 1864, the taxonomy of H. brachysoma, particularly its familial affinities, continues to be in flux. The species, originally described from the erstwhile ‘state of Cochin’ in present day Kerala State, India, has a current distribution ranging from southern Kerala (8°N) to southern Maharashtra (16°N), where they are found in lowland westward-flowing rivers, as well as natural freshwater lakes and backwaters. As a much relished food fish, H. brachysoma is exploited throughout its range, predominantly through an unmanaged artisanal fishery. Although there are no scientific estimates of either the status or trends in overall population of this endemic catfish, anecdotal evidence and fisher-knowledge suggests drastic declines of several local populations. The fishery for H. brachysoma in the Periyar and Achenkovil rivers in the State of Kerala has been documented to be unsustainable. As a result of an overall population decline of 35 % due to overharvest and habitat loss, H. brachysoma is assessed as ‘Vulnerable’ on the IUCN Red List of Threatened Species™. Primary research on various aspects of feeding, reproductive biology and demography has generated a wealth of information on the species, but this knowledge is yet to be utilized for the development and implementation of in situ conservation or management plans. In view of its high consumer demand, efficient biological and eco-physiological characteristics, as well as the availability of a captive breeding technology, H. brachysoma is considered an emerging species for small-scale aquaculture. Priorities for scientific research to address knowledge-gaps, as well as strategies for effective conservation of this threatened freshwater catfish are discussed. © 2016 Springer International Publishing Switzerland Source

Raghavan R.,Outreach | Raghavan R.,Conservation Research Group CRG | Dahanukar N.,Outreach | Dahanukar N.,Indian Institute of Science | And 6 more authors.
Aquatic Conservation: Marine and Freshwater Ecosystems

Freshwater invertebrates receive relatively little publicity and conservation attention, in spite of their key role in aquatic food webs and ecosystem functioning. Decapod crustaceans such as caridean shrimps and gecarcinucid freshwater crabs comprise some of the most poorly known aquatic taxa, even in exceptional regions of freshwater biodiversity and endemism, such as the Western Ghats mountains of peninsular India. An analysis was carried out to understand distribution patterns and identify priority areas for decapod crustacean conservation in the Western Ghats region based on conservation status data retrieved from the IUCN Red List of Threatened Species. The Western Ghats region is home to 49 species and six sub-species of caridean shrimps (69% endemism) in four genera and two families, and 39 species of gecarcinucid crabs (92% endemism) in 14 genera. This diversity is probably an underestimate given the lack of biotic surveys and taxonomic research carried out on these groups. Three species (3%) of decapod crustaceans from the Western Ghats region are threatened with extinction, while more than half (51%; 48 species) are Data Deficient. The uncertainty regarding the true extinction risk of such a high number of Data Deficient species could hamper conservation efforts as well as policy development and implementation. Forty sites in the Western Ghats region are priorities for the conservation of decapod crustaceans, of which only seven lie within the existing network of protected areas. The specialized natural history and point endemic nature of many species of freshwater decapods, together with escalating human impacts on their aquatic ecosystems in the Western Ghats, makes conservation and management of these threatened and poorly-known species an immediate and urgent challenge. © 2014 John Wiley & Sons, Ltd. Source

K. K B.,Central Marine Fisheries Research Institute Campus | A G.,Central Marine Fisheries Research Institute | J. K J.,National Bureau of Fish Genetic Resources | V. S B.,Central Marine Fisheries Research Institute Campus | And 4 more authors.
Mitochondrial DNA

Thirty-five individuals of six priacanthid fish species were sampled from different localities along the coast of India covering the Arabian Sea and Bay of Bengal. The partial sequence of 16S rRNA and cytochrome oxidase subunit I (COI) genes were analyzed for species identification and phylogenetic relationship among the Indian priacanthids (Priacanthus hamrur, P. prolixus, P. blochii, P. sagittarius, Cookeolus japonicus, and Pristigenys refulgens). The intraspecies genetic distance ranged from 0.000 to 0.002, while distances varied from 0.008 to 0.157 interspecies based on 16S sequences. Using COI data analysis, the intraspecies genetic distance ranged from 0.000 to 0.005, while interspecies distances varied from 0.009 to 0.108. Several sequences labeled Priacanthus hamrur in GenBank are shown to be P. prolixus. We also observed cryptic speciation in Heteropriacanthus cruentatus. Partial sequences of 16S rRNA and COI genes provided phylogenetic information to distinguish thirteen species of priacanthids, indicating the usefulness of molecular markers in species identification. © 2015 Taylor & Francis. Source

Schumann J.,Fritz Haber Institute | Eichelbaum M.,Fritz Haber Institute | Lunkenbein T.,Fritz Haber Institute | Thomas N.,Fritz Haber Institute | And 7 more authors.
ACS Catalysis

The promoting effect of Al, Ga, and Mg on the support in Cu/ZnO catalysts for methanol synthesis has been investigated. Different unpromoted and promoted ZnO supports were synthesized and impregnated with Cu metal in a subsequent step. All materials, supports, and calcined and activated catalysts were characterized by various methods, including contactless (microwave) conductivity measurements under different gas atmospheres. Small amounts of promoters were found to exhibit a significant influence on the properties of the oxide support, concerning textural as well as electronic properties. We found correlations between the conductivity of the ZnO support and the activity of the catalyst in the reverse water-gas shift reaction (rWGS) as well as in methanol synthesis. In rWGS the activation energy and reaction order in H2 are decreased upon promotion of the ZnO support with the trivalent promoters Al3+ and Ga3+, indicating an electronic promotion. In methanol synthesis, results point to a structural promotion by Al3+ and Ga3+. A detrimental effect of Mg2+ doping was observed in both reactions. This effect is discussed in the context of the reducibility of ZnO under reaction conditions, which can be tuned by the promoter in different ways. The reducibility is seen as a critical property for the dynamic metal support interaction of the Cu/ZnO system. © 2015 American Chemical Society. Source

Nabipour H.,Shahid Madani University of Azarbaijan | Hosaini Sadr M.,Shahid Madani University of Azarbaijan | Thomas N.,Nirmalagiri College
Journal of Experimental Nanoscience

The intercalation of amoxicillin trihydrate (AMOX) into layered zinc hydroxide (LZH) has been achieved via ion-exchange method. The resulted nanocomposite (AMOX-LZH) has been thoroughly characterised by a number of techniques including powder X-ray diffraction (PXRD), FT-IR spectroscopy, TGA/DTG analysis and scanning electron microscopy (SEM). The PXRD results showed that the gallery height of LZH was expanded from 9.57 to 11.97 Å, indicating that the AMOX anions were successfully intercalated into the interlayer space of LZHs. The increased thermal stability of nanocomposite was confirmed by TGA/DTG analyses. Improved antibacterial activity and minimum inhibitory concentration of AMOX-LZH nanocomposite was evaluated against Gram-positive bacteria Staphylococcus aureus, Klebsiella pneumonia and Gram- negative Escherichia coli using the disk diffusion technique. The sustained release of amoxicillin drug from the AMOX-LZH nanocomposite was also verified. © 2015 Taylor & Francis. Source

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