Project description:The complete mitochondrial genome of stripped eel catfish, Plotosus lineatus, is sequenced in this study. The mitochondrial genome sequence is 16?480?bp in length, with the base composition of 24.7% A, 31.8% T, 27.8% G and 15.7% C. The G?+?C content is 43.5%. The mitochondria includes 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes and one D-loop region. Except for NAD6 gene and eight tRNA genes, all other mitochondrial genes were encoded on the heavy strand. Plotosus lineatus was confirmed to be closely related to P. japonicus (GenBank: KR270437.1), based on our phylogenetic analysis on complete mitochondrial genome sequences of 13 species. Our complete mitogenome data are going to provide the basis for taxonomic and phylogenetic research of catfishes.
Project description:Unique amongst the teleost, Plotosidae catfish possess a dendritic organ (DO) as a purported salt secreting organ, whereas other marine teleosts rely on their gill ionocytes for active NaCl excretion. To address the role of the DO in ionregulation, ligation experiments were conducted in brackish water (BW) 3‰ and seawater (SW) 34‰ acclimated Plotosus lineatus and compared to sham operated fish. Ligation in SW resulted in an osmoregulatory impairment in blood (elevated ions and hematocrit) and muscle (dehydration). However, SW ligation did not elicit compensatory changes in gill or kidney Na+/K+-ATPase (NKA) activity and/or protein expression while a decrease in anterior intestine and increased in posterior intestine were observed but this was not reflected at the protein level. Following ligation in SW, protein levels of carbonic anhydrase (CA) and V-ATPase B subunit (VHAB) were higher in kidney but either lower (CA) or unchanged (VHAB) in other tissues. Taken together, the osmotic disturbance in ligated SW fish indicates the central role of the DO in salt secretion and the absence of a compensatory response from the gill.
