New insight into the toxic effects of lithium in the ragworm Perinereis cultrifera as revealed by lipidomic biomarkers, redox status, and histopathological features.

Lithium (Li) is a toxic monovalent alkaline metal used in household items common to industrial applications. The present work was aimed at investigating the potential toxic effects of LiCl on the redox status, fatty acid composition, and histological aspects of the marine ragworm Perinereis cultrifera. Sea worms were exposed to LiCl graded doses (20, 40, and 80 mg/L) for 48 h. Compared with the control group, the saturated fatty acids (SFA) decreased while monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA) increased upon exposure to LiCl. The increase in PUFA n-3 and PUFA n-6 was concomitant to an increase in docosahexaenoic (DHA: C22:6n-3), eicosapentaenoic (EPA: C20:5n-3), and docosapentaenoic acid (C22:5n-6) fatty acids. Results showed that LiCl-treated specimens accumulate lithium with increasing exposure gradient. Indeed, the exposure to LiCl doses promoted oxidative stress with an increase of the ferric reducing antioxidant power (FRAP), malondialdehyde (MDA), hydrogen peroxide (H2O2), advanced oxidation protein product (AOPP), and protein carbonyl (PCO) as well as the enzymatic and non-enzymatic antioxidants (non-protein thiols (NPSH), catalase (CAT), superoxide dismutase (SOD), reduced glutathione (GSH), glutathione peroxidase (GPx), glutathione S-transferase (GST), and metallothionein (MT)) levels in all treated groups. Our biochemical findings have been affirmed by the histopathological observations showing hyperplasia and loss of the intestine structure in treated specimens. Overall, our findings give new insights on the toxic effect of LiCl on the redox status of P. cultrifera body tissue and highlighted the usefulness of the FA composition as an early sensitive bioindicators to better understand LiCl mechanism of toxicity in marine polychaetes.

Description of a New Species for Asian Populations of the "Cosmopolitan" Perinereis cultrifera (Annelida: Nereididae).

An Asian species of Perinereis, which has been regarded as a local population of a cosmopolitan species P. cultrifera ( Grube, 1840 ) (type locality: Italy), is described as a new species, P. euiini., based on Korean specimens. This new species is distinguishable from P. cultrifera and other similar species such as P. floridana ( Ehlers, 1868 ) (type locality: USA), P. anderssoni Kinberg, 1866 (type locality: Brazil), and P. helleri ( Grube, 1878 ) (type locality: Philippines) by the character combination of the absence of lateral group of paragnaths in area III on the proboscis, the presence of small notopodial prechaetal lobe in anterior parapodia, and the greatly expanded dorsal ligule in posterior parapodia. All previous records of "P. cultrifera" from eastern Asia (Taiwan, China, Japan, and Korea) are judged to belong to P. euiini sp. nov., leading to the conclusion that P. cultrifera is not a cosmopolitan species. Specimens previously identified as P. cultrifera var. floridana (or P. cultrifera floridana) in eastern Asia are also judged to belong to P. euiini sp. nov., although they have different paragnath number in area V (one instead of three). Their aberrant paragnath number was regarded as an intraspecific variation of P. euiini sp. nov. The comparison of DNA sequences of the mitochondrial cytochrome c oxidase subunit I (COI) between P. euiini sp. nov. and "P. cultrifera" from China and Portugal also supports the erection of the new species.

Evidence of coelomic substances inducing genital maturation inPerinereis cultrifera (annelida polychaeta).

Two peptides (B1 and B2) have been isolated from the coelomic fluid ofPerinereis cultrifera. These peptides are absent in sexually undifferentiated animals. They appear and become abundant during the oocyte submaturity stage. When B1 and B2 are simultaneously injected into very young females, they stimulate an important biosynthesis of oocyte glycoconjugates (certical alveoli). Injected separately, B1 or B2 leads to an oocyte structure similar to that of an anhormonal state. The modes of these actions were discussed.