Bagarius

Abstract: Background The yellow sisorid catfish (Bagarius yarrelli) is a carnivorous freshwater fish that inhabits the Honghe River, Lanchangjiang River and Nujiang River of southern China and other Southeast Asian countries. However, the publicly available genomic data for B. yarrelli are limited. Methodology and principal findings Illumina Solexa paired-end technology produced 1,706,456 raw reads from muscle, liver and caudal fin tissues of B. yarrelli. Nearly 5 Gb of data were acquired, and de novo assembly generated 14,607 unigenes, with an N50 of 2006 bp. A total of 9093 unigenes showed significant similarities to known proteins in public databases: 4477 and 6391 of B. yarrelli unigenes were mapped to the Gene Ontology (GO) and Clusters of Orthologous Groups (COG) databases, respectively. Moreover, 9635 unigenes were assigned to 242 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. In addition, 8568 microsatellites (simple sequence repeats, SSRs) were detected, and 31 pairs of polymorphic primers were characterized using wild populations of B. yarrelli from the Nujiang River, Yunnan Province, China. Conclusion/Significance These sequences enrich the genomic resources for B. yarrelli and will benefit future investigations into the evolutionary and biological processes of this and related Bagarius species. The SSR markers developed in this study will facilitate construction of genetic maps, investigations of genetic structures and germplasm polymorphism assessments in B. yarrelli.

Abstract: The cephalic and pectoral girdle structures of the sisorid Glyptothorax fukiensis (tribe Glyptothoracini) are described and compared with those of representatives of the other three sisorid tribes, namely Glyptosternon reticulatum (tribe Glyptosternini), Bagarius yarreli (tribe Bagariini) and Gagata cenia (tribe Sisorini), as well as with those of several other catfishes, as the foundation for a discussion on the synapomorphies and phylogenetic relationships of the Sisoridae. Our observations and comparisons support de Pinna's (1996) phylogenetic hypothesis, according to which the Asiatic Sisoridae is the sister-group of a clade formed by the Neotropical Aspredinidae and the Asiatic Erethistidae. In addition, our observations and com- parisons pointed out a new, additional character to diagnose the family Sisoridae, namely: presence of a well- developed, wide, deep fossa on the neurocranial floor between the ventro-medial surface of the pterotic and the ventro-lateral surface of the exoccipital.

Abstract: The skin surface of Bagarius bagarius was observed primarily by SEM. The epidermis was differentiated into polyhedral, epidermal plaques, separated by deep epidermal furrows. These structures showed significant modifications, associated with their physiological status, in their surface architecture, the epidermal plaques being keratinized and the furrows non-keratinized and mucogenic. The epithelial cells of the keratinized plaques supported projections of fine bristles (unculi). Mucous cells and taste buds were absent. In the non-keratinized mucogenic furrows, the epithelial cells were characterized by intricate patterns of microridges, mucous cells being irregularly distributed and taste buds generally located on epidermal protuberances. The boundaries separating adjacent, keratinized epithelial cells appeared more distinct than those of the non-keratinized mucogenic epithelial cells. The structural peculiarities in the surface sculpture of the skin of B. bagarius apparently reflect functional adaptations.

Abstract: In this study, we first inferred the genetic variability of two Bagarius bagarius populations collected from Ganges and Brahmaputra rivers of India using two mtDNA markers. Sequence analysis of COI gene did not show significant differences between two populations whereas cytochrome b gene showed significant differences between two populations. Followed by, genetic relationship of B. bagarius and B. yarrielli was analyzed using COI and cytochrome b gene and the results showed a higher level genetic variation between two species. The present study provides support for the suitability of COI and cytochrome b genes for the identification of B. bagarius and B. yarrielli.