Molecular characterization of a signal-regulated kinase homolog from Echinococcus granulosus / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Cystic echinococcosis due to Echinococcus granulosus (E. granulosus) is one of the most important chronic helminthic diseases, especially in sheep/cattle-raising regions. The larval stage of the parasite forms a cyst that grows in the liver, lung, or other organs of the host. To ensure a long life in the host tissues, the parasite establishes complex inter-cellular communication systems between its host to allow its differentiation toward each larval stage. Recent studies have reported that this communication is associated with the extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase cascade in helminth parasites, and in particular that these protein kinases might serve as effective targets for a novel chemotherapy for cystic echinococcosis. The aim of the present study investigated the biological function of a novel ERK ortholog from E. granulosus, EgERK.</p><p><b>METHODS</b>DNA encoding EgERK was isolated from protoscolices of E. granulosus and analyzed using the LA Taq polymerase chain reaction (PCR) approach and bioinformatics. Reverse transcription PCR (RT-PCR) was used to determine the transcription level of the gene at two different larval tissues. Western blotting was used to detect levels of EgERK protein. The expression profile of EgERK in protoscolices was examined by immunofluorescence.</p><p><b>RESULTS</b>We cloned the entire Egerk genomic locus from E. granulosus. In addition, two alternatively spliced transcripts of Egerk, Egerk-A, and Egerk-B were identified. Egerk-A was found to constitutively expressed at the transcriptional and protein levels in two different larval tissues (cyst membranes and protoscolices). Egerk-A was expressed in the tegumental structures, hooklets, and suckers and in the tissue surrounding the rostellum of E. granulosus protoscolices.</p><p><b>CONCLUSIONS</b>We have cloned the genomic DNA of a novel ERK ortholog from E. granulosus, EgERK (GenBank ID HQ585923), and found that it is constitutively expressed in cyst membrane and protoscolex. These findings will be useful in further study of the biological functions of the gene in the growth and development of Echinococcus and will contribute to research on novel anti-echinococcosis drug targets.</p>

Isolation and characterization of Hantavirus carried by rodents in Huludao, Liaoning province / 中华流行病学杂志

<p><b>OBJECTIVE</b>To investigate the Hantavirus infection and their genotype in rodents in Huludao.</p><p><b>METHODS</b>Rodents were collected from the main epidemic areas to detect antigen of Hantavirus in rat lungs by indirect immunofluorescence assay. Antigen-positive samples were inoculated onto cultures of confluent Vero E6 cells for the isolation of virus. The genotypes of viruses in all antigen-positive samples were identified by reverse transcriptase-polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>200 rats were collected in the main epidemic areas, and 11 Hantavirus-positive samples were tested. The positive rate of Hantavirus in rats was 5.5%. Three strains of Hantavirus were isolated in Vero E6 cell culture. Data from the phylogenetic trees constructed by partial S segment (620-999 nt) or partial G1 segment (180-580 nt) showed that the three isolates carried by rats from Huludao were all genetic subtype SEOV 3. Furthermore, the phylogenetic tree constructed by partial G2 segment (2003-2302 nt) divided SEOV strains into 7 genetic subtypes, and the three isolates were having a closer evolutionary relationship with isolates CP211, ch302 and dc501 from Beijing, and the isolates SD10 and SD227 form Shandong.</p><p><b>CONCLUSION</b>Data indicated that the rate of carrying virus was high and the main genetic subtype of Hantavirus was S3 of Seoul virus in Huludao area.</p>