Generalized system of imposex and reproductive failure in female gastropods of coastal waters of mainland China

Abstract

We investigated the occurrence of imposex in gastropods from the coastal waters of mainland China from November 1999 to July 2004. Imposex was found in 30 species from 8 families, and was recorded in 20 species for the first time. In addition to the already known phenotypes of imposex expression in Cantharus cecillei, we also found aborted egg capsules in specimens with a split ventral channel (stage and type classification: S 6c* ) and various extensions of the proximal vas deferens (PVD). The PVD went up to or passed by the vaginal opening, and then it stopped or continued along the capsule gland. In imposex females, the penis shape and the development of the vas deferens were similar to those of the male of the same species. The morphological expressions of imposex showed diverse stages and types. Reproductive failure of females occurred in 13 species. The results suggest that imposex is widespread and severe in the coastal waters of China. Based on our aims of ecological and morphological significance, a typical imposex classification could be further generalized for all 30 species by adding S 6c(*) and 2 subdivisions of the PVD. The generalized scheme was also ascertained to be valid for several morphological variations of imposex in previous work. Sterility at S 6c(*) was proven to be due to the infolding of the capsule gland wall. We thus summed up 4 mechanisms of sterility (a, b, c and *) in females. Furthermore, it was shown that the normal structure of the male genital system also affected the morphological expressions of imposex to some degree, which we referred to as 'effect of male structure'. Finally, we put forward a general classification scheme of imposex with an integrated system of aims, criteria, stages, types (subtypes), pathways and mechanisms of imposex. KEY WORDS: Imposex · Gastropod · Sterility · Mainland ChinaResale or republication not permitted without written consent of the publisher

Laboratory Tests with Androgenic and Anti-Androgenic Pesticides – Comparative Studies on Endocrine Modulation in the Reproductive System of Invertebrates and Vertebrates

“…More than 150 molluscan species worldwide were affected by the endocrine modulation induced by TBT. Deriving from laboratory experiments and in situ studies it was evident that the endocrine effects could be induced at extremely low concentration of 0.1 ng/L TBT (Oehlmann et al 2007;Shi et al 2005). In most species TBT is able to induce a phenomenon called imposex, the appearance of male sexual characteristics in females.…”

Tintas anti-incrustantes de terceira geração: novos biocidas no ambiente aquático

“…10,11 Por outro lado, é sabido que alguns países em desenvolvimento seguem utilizando estes compostos. 12 Em razão dos problemas ambientais associados ao uso de tintas à base de organoestânicos e seu gradativo banimento mundial, uma terceira geração de tintas anti-incrustantes começou a ser utilizada a partir de 1987. Esse novo grupo de tintas contempla atualmente 16 diferentes compostos biocidas que estão homologados pela IMO para utilização em embarcações (Tabela 1).…”

Organotin pollution in China: An overview of the current state and potential health risk

“…Many countries have developed methods that use imposex status of native gastropods to predict contamination of aquatic environments. Imposex of gastropods in China has been widely observed in organotin-polluted coastal waters (Shi et al, 2005), however, few cases have been reported which used this phenomenon for biological monitoring. The following reviews the preliminary research about species that have been considered for biomarker candidates in China in the future.…”

“…In total, imposex has been documented in over 150 gastropod species (Matthiessen et al, 1999). In the coastal waters of China, imposex of gastropods is a widely reported problem related to organotin pollution (Shi et al, 2005). Indeed, among the countries of the world, Asia is one of the most organotin contaminated, where imposex has been shown in 100% of oysters in some ports of Taiwan and Japan (Sun et al, 2005).…”