Transcriptomic analysis and oxidative stress induced by sodium dichloroisocyanurate in the intestine of Phascolosoma esculenta.

Sodium dichloroisocyanurate (NaDCC, C3Cl2N3NaO3) is a solid chlorine-containing product that is widely used as a disinfectant in living environments, which has potential toxic effects on human and rats. Phascolosoma esculenta is a species native to the southeast coast of China and can be used as an indicator organism. In the present study, 150 P. esculenta were used to determine the LC50 of NaDCC for P. esculenta, then 100 P. esculenta were used to analysis the change of histopathology, oxidative stress and transcriptome after NaDCC exposure. The results showed that the LC50 of NaDCC for 48 h was 50 mg/L. NaDCC stress induced pathological events in P. esculenta, including blisters, intestinal structural damage and epithelial cell ruptured or even loss. The highest and lowest intestinal activity of superoxide dismutase in individual survivors was detected at 12 h and 72 h, respectively. Malondialdehyde levels in the intestine declined gradually from 3 h and increased at 9 h, and peaked at 12 h. Total antioxidant capacity declined at 3 h and dropped below the levels of control group after 9 h. Transcriptome sequencing analysis yielded a total of 48.65 Gb of clean data. A total of 34,759 new genes were found including 957 differentially expressed genes (DEGs). The DEGs were significantly enriched in ferroptosis, response to chemicals, response to stress, immune system, ion transport, cell death, oxidation-reduction, cellular homeostasis, protein ubiquitination, and protein neddylation. Additionally, the levels of detoxification enzymes, such as glutathione-S-transferase, cytochrome P450, ABC, UDP-glycosyltransferase and SLC transporters of endogenous and exogenous solutes were significantly changed. Overall, the results provide reference for reasonable use of disinfectants during farming, and also provide insight into the mechanisms related to NaDCC toxicity in P. esculenta.

Development and validation of genome-wide SSR molecular markers of Tapes dorsatus.

BACKGROUND: Tapes dorsatus is an economically important benthic animal in the Beibu Gulf of China. However, the deficiency of microsatellite markers has hindered the study of its genetics. The development of microsatellite markers will provide useful tools for genetic improvement, variety identification, phylogenetic analysis and resource conservation. METHODS AND RESULTS: Within the genome sequence, 145,008 simple sequence repeats (SSRs) were identified, and 29,691 primer pairs were designed successfully. A total of 100 primer pairs were randomly synthesized for testing, and 93 primers yielded products. Sixty highly polymorphic primers were used to reveal the genetic diversity of 50 T. dorsatus individuals. The average number of alleles (Na) of the population was 10.40; the average number of effective alleles was 6.16, the average expected heterozygosity (He) was 0.82, and the average polymorphic information content was 0.80. The genetic structure of the population was detected, by which the population could be divided into three subpopulations. CONCLUSION: We identified 145,008 SSRs in the genome of T. dorsatus and designed 29,691 primer pairs in this study. Of 100 synthesized primers, 60 were highly polymorphic and used to reveal the genetic diversity and structure of the population. The SSR markers identified here will provide useful tools and a foundation for genetic diversity, linkage mapping and molecular marker-aided breeding in T. dorsatus.