Triphenyltin exposure induced abnormal morphological colouration in adult male guppies (Poecilia reticulata).

Fish morphological colouration is essential for their survival and reproduction success; however, it is vulnerable to environmental factors, such as pollutants. Triphenyltin (TPT) is widespread in aquatic ecosystems, and its impacts on fish have been problematic. Therefore, the purpose of this study was to investigate the effects of TPT at environment-related concentrations (0, 1, 10 and 100 ng Sn/L) on morphological colouration in male guppies (Poecilia reticulata). The results showed that TPT exposure affected both orange/red and dark morphological colouration in guppies. The faded orange/red colouration might be related to the decrease of coloured pteridine and Pts (6-Pyruvoyltetrahydropterin Synthase) expression. In addition, TPT exposure induced melanogenesis, however, much melanin was distributed diffusely in the skin and did not seem to form a spot pattern, giving the fish a dull appearance. According to the skin transcriptional profiles, the changes of dark morphological colouration might be related to the changes in genes related to the functions of melanosome components (Gpnmb, Slc45a2 and Tyr), construction (Ap3d1, Fig4, Hps3, Hps5, Lyst, Rabggta, Txndc5 and Vps33a), and transport (Rab27a). Additionally, genes related to the regulation of melanogenesis (Atrn and Pomc) and system effects (Atox1, Atp6ap2, Atp6v1f, Atp6v1h, Rpl24, Rps19 and Rps20) might also be involved in the molecular mechanisms of abnormal morphological colouration induced by TPT. The present study provides crucial data on the molecular basis of abnormal morphological colouration in fish exposed to TPT and underscores the importance of toxicological studies of the effects of pollutants in aquatic environments on fish morphological colouration.

Complete chloroplast genome of an Endangered mangrove plant Hernandia nymphiifolia (C. Presl) Kubitzki (Hernandiaceae).

This study presents the chloroplast genome of Hernandia nymphiifolia (C. Presl) Kubitzki (Hernandiaceae) one Endangered mangrove species in China, which was assembled and analyzed by de novo assembly using whole chloroplast genome sequencing data. The accessing ID of reference sequence was MG838431. The size of the complete chloroplast genome was 157,762 bp in length with a large single-copy region (LSC) of 86,641 bp, a small single-copy region (SSC) of 18,603 bp, and two inverted repeat regions (IRS) (26,260 bp). The GC content of H. nymphiifolia is 39.3%. From the chloroplast genomes, 133 genes, including 83 protein-coding genes, 42 tRNA genes, and 8 rRNA genes, were predicted. Among them, 17 genes occur in IRS, containing 6 protein-coding genes, 7 tRNA genes and 4 rRNA genes. The phylogenetic analysis with 10 eudicots species and rice as the outgroup revealed that H. nymphiifolia was clustered with 6 Ranunculales species.