Characterization of development-related genes for the cestode Bothriocephalus acheilognathi

Asian Fish Tapeworm: The Most Successful Invasive Parasite in Freshwaters

The Asian fish tapeworm (AFT), Schyzocotyle acheilognathi, is a notorious and highly successful invasive parasite reported in a wide spectrum of freshwater fishes, and new reports of its spread continue to emerge. To date, no thorough review of its worldwide distribution and host associations is available. In the present work, we collected information from 651 articles up until 2017, from which we updated the number of the hosts to 312 fish species and 11 non-fish species, which is quite unusual among helminths. The AFT has spread to all but one continent (Antarctica). The highest number of records are from North America, followed by Asia and Europe. A key feature of its invasive success is its broad environmental tolerance.

Analysis of early hepatic stage schistosomula gene expression by subtractive expressed sequence tags library

Schistosome parasites require a complex lifecycle requiring two hosts and aquatic phases of development. The schistosomula is a key phase of parasite development within the mammalian host, however relatively little is understood about the molecular processes underlying this stage. In this study 5723 subtractive expressed sequence tags (ESTs) were randomly selected from a 7 day hepatic schistosomula enriched library constructed using suppression subtractive hybridization method. Sequence analysis of these ESTs identified 1762 unique genes (contigs). Among them, 989 contigs were annotated with known genes, 311 contigs were homologous to established genes, 101 contigs were similar to established genes, 72 contigs were weakly similar to established genes and 289 sequences did not match any published sequences. Genes identified related to metabolism, cellular development, immune evasion and host-parasite interactions were identified as enriched in the hepatic schistosomula stage. The future identification of poorly annotated but stage-specific genes may potentially represent new drugs or vaccine targets, applicable for the future controlling of schistosomiasis.

Identification of stage-specifically expressed genes ofTrichinella spiralisby suppression subtractive hybridization

Newborn larvae (NBL) and adult (Ad) stage-specifically expressed genes or members of gene families ofTrichinella spiraliswere identified by suppression subtractive hybridization (SSH)†. Six cDNA clones were identified as NBL stage-specific, including 1 member of theT. spiralisgene family encoding glutamic acid-rich proteins, 2 clones encoding novel serine proteases, 2 closely related clones encoding proteins that are members of a deoxyribonuclease II (DNase II)-like family and 1 clone with no similarity to known genes. Four stage-specific clones encoding homologues of retinoid X receptor, caveolin, C2H2 type zinc finger protein and a putative protein with no homology to known sequences were obtained from 3-day-old adult worms. One gene specifically up-regulated in the 5-day-old adult worms encoding a putative cuticle collagen was also identified.

Identification of differentially expressed genes in female Culex pipiens pallens

Culex pipiens pallens is the mosquito vector of a number of human pathogens such as Wuchereria bancrofti, Brugia malayi, and epidemic encephalitis B virus. Female C. pipiens pallens play an important role in transmitting pathogens by sucking blood, which is essential for reproduction. In the present study, a subtractive cDNA library for female C. pipiens pallens was constructed by the suppression subtractive hybridization (SSH) technique and then 100 clones from the female SSH library were sequenced and analyzed. Female-differentially expressed genes in C. pipiens pallens were screened using semiquantitative RT-PCR. The full-length cDNA of an EST sequence (fs68) that was specifically expressed in female C. pipiens pallens was characterized by 3' and 5' rapid amplification of cDNA ends (RACE). The characteristics of the female-specific gene were further analyzed using bioinformatics and Northern blot. It was shown that the female-specific gene was a previously uncharacterized gene and may encode a salivary peptide. This putative salivary peptide could be a very important molecule in the blood feeding of female C. pipiens pallens.

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.