[Identification and preliminary analysis of a novel full-length cDNA encoding retinoid X receptor 2 from Schistosoma japonicum].

OBJECTIVE: To clone and preliminarily analyze the full-length cDNA encoding retinoid X receptor 2 (RXR2) from Schistosoma japonicum. METHODS: The rapid amplification cDNA ends (RACE)was applied to get a full-length cDNA encoding retinoid X receptor 2 from S. japonicum (SjRXR2). The transcription of SjRXR2 was detected by real-time PCR. By bioinformatical technology, the gene structure was analyzed and the antibody epitope was predicted. The polyclonal antibodies were raised in mice immunized with the synthesis peptide. Western blot was applied to detect its expression in the worm. RESULTS: The full-length cDNA of SjRXR2 was 5 960 bp and contained an open reading frame encoding a 1 435 amino acid which had a predicted molecular weight 159 kDa. Bioinformatical analysis indicated that SjRXR2 had a highly conserved DNA binding domain (DBD) and a moderate conserved ligand binding domain (LBD). The relative mRNA (s) of SjRXR2 with higher expressions at Day 21 and 42 were evaluated in five different S. japonicum developmental stages. The Western blot analysis showed that polyclonal antibodies were able to specifically recognize the protein with molecular around 150 kDa from the extract of S. japonicum. CONCLUSION: A full-length cDNA encoding retinoid X receptor 2 (RXR2) from S. japonicum is obtained which provides preliminary information for further investigation of SjRXR2 functions in S. japonicum.

A checklist of parasitic nematodes from marine fishes of China.

A checklist of the parasitic nematodes of Chinese marine fishes is presented. This fauna comprises 90 species, representing 31 genera, 13 families, nine superfamilies, three orders and two subclasses. Additional details for each species include the hosts, localities and references which represent the source of these data.

Digenean parasites of Chinese marine fishes: a list of species, hosts and geographical distribution.

In the literature, 630 species of Digenea (Trematoda) have been reported from Chinese marine fishes. These belong to 209 genera and 35 families. The names of these species, along with their hosts, geographical distribution and records, are listed in this paper.

A new species of haploporid (Digenea) from the South China Sea.

Megasolena dongzhaiensis n. sp. was collected from the intestine of Scatophagus argus (Linnaeus) (Perciformes: Scatophagidae) from the Dongzhai Bay (110 degrees 32'-37'E, 19 degrees 51'-20 degrees 1'N), Hainan Province, China. It resembles Megasolena acanthuri Machida and Uchida, 1991 in having larger body size, but it differs from the latter species in having an oral sucker that is larger, instead of smaller, than the acetabulum (sucker length ratio 1:0.456-0.494, and width ratio 1:0.61-0.65 in M. dongzhaiensis n. sp., as opposed to 1:1.3-1.7 in M. acanthuri). Moreover, the cuticle is spinose rather than aspinose; there is a band of circular muscle in the pharynx, and its eggs are smaller instead of larger (0.062-0.068 x 0.036-0.039 in M. dongzhaiensis n. sp., compared with 0.087-0.103 x 0.058-0.072 in M. acanthuri). Finally, the intestinal bifurcation is anterior, instead of dorsal, to the acetabulum. It resembles other species of Megasolena Linton, 1910 in having oral sucker larger than the acetabulum, and in having a circular muscle band in the oral sucker and pharynx, but it differs in having a larger body and smaller eggs. This is the first record of a Megasolena species from ray-finned fishes as well as in China.

A new pseudophyllidean from a freshwater fish, Gambusia affinis, in China.

Coelobothrium gambusiense n. sp. (Bothriocephalidae) was collected and described from the intestine of the freshwater fish Gambusia affinis (Baird and Girard) (Poeciliidae) in Fujian Province, Peoples' Republic of China. It is the first record of Coelobothrium in China. The parasite closely resembles Coelobothrium monodi Dollfus, 1970, from Capoeta damascina (Valenciennes, Cyprinidae) in Iran and Coelobothrium oitense Kugi and Matsuo, 1990, from Tribolodon hakonensis (GUnther, Cyprinidae) in Japan in general morphological characters, the scolex, and the incomplete proglottids. The third species of Coelobothrium is distinguished from its congeners by its much shorter strobila, presence of a neck, a bilobed ovary instead of a transversely elongated ovary, larger eggs, different final host and locality, and other morphological characters.

Saccocoelium megasacculum n. sp., a new haploporid trematode from Liza carinatus in the Taiwan strait.

Saccocoelium megasacculum n. sp. (Digenea: Haploporidae) was collected from the intestine of the mugilid fish. Liza carinatus (Cuvier and Valenciennes), in the Taiwan Strait. It is the first record of Saccocoelium in China. The parasite most closely resembles Saccocoelium obesum Looss, 1902 and Saccocoelium tensum Looss, 1902 in general morphology and body size, but it is easily distinguished from them in having a larger hermaphroditic sac in relation to body size; larger eggs; smaller pharynx, testis, ovary, and vitellaria; and a uterine seminal receptacle instead of a true seminal receptacle.

Lasiotocus lizae sp. n. (Digenea: Monorchiidae), a new trematode from marine fish in the Taiwan Straits, China.

Lasiotocus lizae sp. n. (Digenea: Monorchiidae) was collected from the intestine of Liza carinata (Valenciennes) (Mugilidae, Perciformes) in the Taiwan Straits, China. L. lizae is most similar to Lasiotocus glebulentus Overstreet, 1971 from the intestine of Mugil cephalus from the Northern Gulf of Mexico in having tightly compacted vitellaria, a genital pore sinistral to the midline, the ovary usually dextral to the acetabulum, the similar sucker ratio, and in the presence of both a canalicular and uterine seminal receptacle. It differs from L glebulentus in its cirrus sac ending anterior to rather than posterior to acetabulum, in the ending position of caeca, in smaller eggs, and in having a single rather than several conspicuous concretions in excretory vesicle.

Haploporus mugilis sp. n. (Digenea: Haploporidae) from Valamugil engeli (Pisces: Mugilidae) in the Taiwan Straits, China.

Haploporus mugilis sp. n. (Digenea: Haploporidae) was obtained from the intestine of kandas, Valamugil engeli (Bleeker) (Mugilidae, Perciformes) in the Taiwan Straits, China. It most closely resembles Haploporus spinosus Machida, 1996 from the intestine of Crenimugil crenilabis in Japanese and adjacent waters in the intestinal bifurcation posterior to the acetabulum, in egg-size (0.039-0.044 x 0.019-0.022 in H. mugilis and 0.034-0.042 x 0.018-0.023 in H. spinosus) and in the hermaphroditic sac armed with spines. However, it differs from the latter in its hermaphroditic sac with two long and numerous small spines rather than with four long and six small spines and in the excretory vesicle with a single prominent refractory concretion instead of being empty.

Two new species of lepocreadiid trematodes of marine fishes from the Taiwan Straits, China.

Two new species of lepocreadiid trematodes are reported from marine fishes from the Taiwan Straits, China: Diploproctodaeum spinosus n. sp. from the intestine of Takifugu oblongus (= Fugu oblongus) and Preptetos parapristipomae n. sp. from Parapristipoma trilineatum. Diploproctodaeum spinosus differs from the known species of Diploproctodaeum, with 1 spine at the base of the ejaculatory duct. Preptetos parapristipomae is most similar to Preptetos rotto in having an entire ovary but differs from it in the sucker ratio, distribution of the uterus, position of the cirrus sac, and locality.

Two new species of Pseudohapladena yamaguti, 1952 (Digenea: Waretrematidae) from mugilid fish from the Taiwan Straits, China.

Two new species of Pseudohapladena Yamaguti, 1952 (Digenea: Waretrematidae) are described. Pseudohapladena megoorchis n. sp. was obtained from the intestine of Mugil engeli (Bleeker) (Mugilidae), and Pseudohapladena lizae n. sp. from the intestine of Liza carinatus (Cuvier and Valenciennes) (Mugilidae). Pseudohapladena megaorchis is the most closely related in general morphology to Pseudohapladena scatophagi Yamaguti, 1952, but differs from the latter in the position of the hermaphroditic sac, and in the nature and distribution of the vitellaria. Features of P. lizae distinguishing it from other species of the genus include the shorter uterus, which contains only 1 egg, and the lesser extent of the vitellaria.

Phanurus oligoovus gen. et sp. nov. (Digenea: Waretrematidae) from Liza carinatus from the South China Sea.

The species Phanurus oligoovus gen. et sp. nov. is described from the intestine of Liza carinatus (Cuvier et Valencienne) from the South China Sea. From the general internal anatomy, it belongs to the Waretrematidae and is distinguished from the other known species of the Waretrematidae by the tail appendage. A new subfamily, Phanurunae, is proposed for the genus Phanurus.