Although antibacterial silver nanoparticles (AgNPs) are increasingly released into the environment and are very toxic to aquatic organisms, their effects on bacteria-based holobionts have been rarely studied.

Background Although parasitic isopods can negatively affect the reproduction and ingestion of several commercially important crustaceans, little is known regarding the mechanisms that underlie these effects. Methods In the present study, the iTRAQ (isobaric tags for relative and absolute quantification) approach was applied to identify differentially expressed proteins in the Chinese grass shrimp Palaemonetes sinensis infected with the parasitic isopod Tachaea chinensis . Results On the basis of our analysis, we identified 1262 proteins from a total of 4292 peptides. There was a significant difference in the expression of 182 proteins between the control and infected groups, among which 69 were upregulated and 113 were downregulated after T. chinensis infection. The differentially expressed proteins revealed that parasitism may inhibit the immune response, thereby increasing host vulnerability to additional lethal infection. Furthermore, T. chinensis may secrete anticoagulants to inhibit hemolymph clotting. Moreover, the isopod parasite placed a heavy metabolic burden on the host, particularly with respect to glucose metabolism. Conclusions Our study is the first to use the iTRAQ-based proteomic approach to analyze the effects of an isopod parasite on its host. The results we obtained using this approach will make a valuable contribution to understanding the molecular mechanisms underlying isopod parasitism on crustaceans.

Tachaea chinensis Thielemann, 1910 (Isopoda: Corallanidae) is a branchial ectoparasite that attaches onto shrimps and prawns. However, the distribution of T. chinensis in China, especially its epidemiology, remains unclear. We determined the prevalence of T. chinensis on the ridgetail white prawn (Exopalaemon carinicauda Holthuis, 1950) in Jiangsu Province. Fifty ponds in 10 shrimp farms were assessed. Isopod species were identified by morphological features and mitochondrial 16S rRNA gene analysis. A literature review was performed to determine the geographical distribution of T. chinensis in China. Published data revealed that T. chinensis was geographically distributed throughout five provinces in China, including Liaoning, Tianjin, Henan, Hubei, and Guangxi. A total of 998 T. chinensis were collected from 50 ridgetail white prawn ponds in Yancheng City and Rudong County. Tachaea chinensis prevalence ranged from 0.98% to 4.42% in Yancheng City and 0.62% to 0.92% in Rudong County. This is the first study to investigate the geographical distribution of T. chinensis in China and determine the prevalence of T. chinensis on the ridgetail white prawn in Jiangsu Province. Overall, we provide available data that fill gaps in the epidemiology of T. chinensis.