Molecular Characteristics and Potent Immunomodulatory Activity of Fasciola hepatica Cystatin

Cystatin, a cysteine protease inhibitor found in many parasites, plays important roles in immune evasion. This study analyzed the molecular characteristics of a cystatin from Fasciola hepatica (FhCystatin) and expressed recombinant FhCystatin (rFhcystatin) to investigate the immune modulatory effects on lipopolysaccharide-induced proliferation, migration, cytokine secretion, nitric oxide (NO) production, and apoptosis in mouse macrophages. The FhCystatin gene encoded 116 amino acids and contained a conserved cystatin-like domain. rFhCystatin significantly inhibited the activity of cathepsin B. rFhCystatin bound to the surface of mouse RAW264.7 cells, significantly inhibited cell proliferation and promoted apoptosis. Moreover, rFhCystatin inhibited the expression of cellular nitric oxide, interleukin-6, and tumor necrosis factor-α, and promoted the expression of transforming growth factor-β and interleukin-10. These results showed that FhCystatin played an important role in regulating the activity of mouse macrophages. Our findings provide new insights into mechanisms underlying the immune evasion and contribute to the exploration of potential targets for the development of new drug to control F. hepatica infection.

Molecular detection and genetic diversity of bovine papillomavirus in dairy cows in Xinjiang, China

Background@#Bovine papillomatosis is a type of proliferative tumor disease of skin and mucosae caused by bovine papillomavirus (BPV). As a transboundary and emerging disease in cattle, it poses a potential threat to the dairy industry. @*Objectives@#The aim of this study is to detect and clarify the genetic diversity of BPV circulating in dairy cows in Xinjiang, China. @*Methods@#122 papilloma skin lesions from 8 intensive dairy farms located in different regions of Xinjiang, China were detected by polymerase chain reaction. The genetic evolution relationships of various types of BPVs were analyzed by examining this phylogenetic tree. @*Results@#Ten genotypes of BPV (BPV1, BPV2, BPV3, BPV6, BPV7, BPV8, BPV10, BPV11, BPV13, and BPV14) were detected and identified in dairy cows. These were the first reported detections of BPV13 and BPV14 in Xinjiang, Mixed infections were detected, and there were geographical differences in the distribution of the BPV genotypes. Notably, the BPV infection rate among young cattle (< 1-year-old) developed from the same supply of frozen sperm was higher than that of the other young cows naturally raised under the same environmental conditions. @*Conclusions@#Genotyping based on the L1 gene of BPV showed that BPVs circulating in Xinjiang China displayed substantial genetic diversity. This study provided valuable data at the molecular epidemiology level, which is conducive to developing deep insights into the genetic diversity and pathogenic characteristics of BPVs in dairy cows.

Molecular detection and genetic diversity of bovine papillomavirus in dairy cows in Xinjiang, China

Background@#Bovine papillomatosis is a type of proliferative tumor disease of skin and mucosae caused by bovine papillomavirus (BPV). As a transboundary and emerging disease in cattle, it poses a potential threat to the dairy industry. @*Objectives@#The aim of this study is to detect and clarify the genetic diversity of BPV circulating in dairy cows in Xinjiang, China. @*Methods@#122 papilloma skin lesions from 8 intensive dairy farms located in different regions of Xinjiang, China were detected by polymerase chain reaction. The genetic evolution relationships of various types of BPVs were analyzed by examining this phylogenetic tree. @*Results@#Ten genotypes of BPV (BPV1, BPV2, BPV3, BPV6, BPV7, BPV8, BPV10, BPV11, BPV13, and BPV14) were detected and identified in dairy cows. These were the first reported detections of BPV13 and BPV14 in Xinjiang, Mixed infections were detected, and there were geographical differences in the distribution of the BPV genotypes. Notably, the BPV infection rate among young cattle (< 1-year-old) developed from the same supply of frozen sperm was higher than that of the other young cows naturally raised under the same environmental conditions. @*Conclusions@#Genotyping based on the L1 gene of BPV showed that BPVs circulating in Xinjiang China displayed substantial genetic diversity. This study provided valuable data at the molecular epidemiology level, which is conducive to developing deep insights into the genetic diversity and pathogenic characteristics of BPVs in dairy cows.

Characteristic profiles of biofilm, enterotoxins and virulence of Staphylococcus aureus isolates from dairy cows in Xinjiang Province, China

As an important zoonotic pathogen, Staphylococcus aureus has led to serious mastitis and endometritis in infected dairy cows. In this study, a total of 164 strains of S. aureus were isolated from dairy cows in Xinjiang Province, China, and subjected to assays to determine drug susceptibility and biofilm (BF) formation ability. Enterotoxin-related genes were detected, and the transcription levels of genes related to BF formation were determined by using reverse transcription-quantitative polymerase chain reaction. Moreover, the pathogenicity of isolates with different BF formation abilities was determined by measuring their hemolysis activity, half lethal dose (LD₅₀) and organ bacterial load. The results showed that 86.0% of S. aureus isolates could form BF. Among them, 42.1% of the strains had weak BF formation ability, and most strains with a strong BF formation ability were ica gene carriers. The S. aureus isolates displayed multidrug resistance and their drug resistance was positively correlated with their BF formation ability. Moreover, 96.3% of the S. aureus isolates carried enterotoxin genes. Among them, the detection rates of the novel enterotoxin genes were higher than those of conventional enterotoxin genes. Furthermore, isolates with a strong BF formation ability had higher LD50 but lower hemolysis ability and organ bacterial load than those of the isolates with weak or no BF ability. However, isolates without BF ability produced more severe pathological changes than those of isolates with strong BF formation ability. These findings suggest that higher BF ability and presence of novel enterotoxin genes are important characteristics of S. aureus isolates from dairy cows in Xinjiang Province, China, and such isolates may pose potential threats to food safety.

Infection of Taenia asiatica in a Bai Person in Dali, China

We report here a human case of Taenia asiatica infection which was confirmed by genetic analyses in Dali, China. A patient was found to have symptoms of taeniasis with discharge of tapeworm proglottids. By sequencing of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene, we observed nucleotide sequence identity of 99% with T. asiatica and 96% with T. saginata. Using the cytochrome b (cytb) gene, 99% identity with T. asiatica and 96% identity with T. saginata were found. Our findings suggest that taeniasis of people in Dali, China may be mainly caused by T. asiatica.

Codon Usage Bias and Determining Forces in Taenia solium Genome

The tapeworm Taenia solium is an important human zoonotic parasite that causes great economic loss and also endangers public health. At present, an effective vaccine that will prevent infection and chemotherapy without any side effect remains to be developed. In this study, codon usage patterns in the T. solium genome were examined through 8,484 protein-coding genes. Neutrality analysis showed that T. solium had a narrow GC distribution, and a significant correlation was observed between GC12 and GC3. Examination of an NC (ENC vs GC3s)-plot showed a few genes on or close to the expected curve, but the majority of points with low-ENC (the effective number of codons) values were detected below the expected curve, suggesting that mutational bias plays a major role in shaping codon usage. The Parity Rule 2 plot (PR2) analysis showed that GC and AT were not used proportionally. We also identified 26 optimal codons in the T. solium genome, all of which ended with either a G or C residue. These optimal codons in the T. solium genome are likely consistent with tRNAs that are highly expressed in the cell, suggesting that mutational and translational selection forces are probably driving factors of codon usage bias in the T. solium genome.

Sequence Analysis and Molecular Characterization of Wnt4 Gene in Metacestodes of Taenia solium

Wnt proteins are a family of secreted glycoproteins that are evolutionarily conserved and considered to be involved in extensive developmental processes in metazoan organisms. The characterization of wnt genes may improve understanding the parasite's development. In the present study, a wnt4 gene encoding 491amino acids was amplified from cDNA of metacestodes of Taenia solium using reverse transcription PCR (RT-PCR). Bioinformatics tools were used for sequence analysis. The conserved domain of the wnt gene family was predicted. The expression profile of Wnt4 was investigated using real-time PCR. Wnt4 expression was found to be dramatically increased in scolex evaginated cysticerci when compared to invaginated cysticerci. In situ hybridization showed that wnt4 gene was distributed in the posterior end of the worm along the primary body axis in evaginated cysticerci. These findings indicated that wnt4 may take part in the process of cysticerci evagination and play a role in scolex/bladder development of cysticerci of T. solium.

Suckling mouse model establishment of myocarditis induced by foot-and-mouth disease vi rus / 中国人兽共患病学报

Interactions between FMDV and cardiac cells are multifaceted and complex ,these interactions leads to pro-teins alterations in cardiac cells inevitably .To understand the pathogenesis of myocarditis after FMDV infection in mice ,the suckling mouse model for myocarditis induced by foot-and-mouth disease virus (FMDV) was established in this study .Suckling mice within 3 days old was selected to infect by FMDV .Myocarditis caused by FMDV in suckling mice was confirmed with clinical symptom monitor .The observation of Hematoxylin and eosin stain (H&E stain) and transmission electron microscopy (TEM) were performed after samples processing .According to conventional polymerase chain reaction (PCR) methods ,prim-ers of VP1 gene was designed ,synthesised and specific FMDV VP1 gene was amplified from the heart muscle of suckling mice . The results indicated that suckling mice appeared low spirit condition ,dyspnea ,and dull reaction within 36 hours after chal-lenge with FMDV .Infiltration of inflammatory cells and dissolution of myocardial fibers were observed with H&E stain and TEM .Special target gene of FMDV was amplified from the heart of infected group .Obvious inflammation in the heart of suck-ling mice caused by FMDV was observed .It's suggested that suckling mouse model for myocarditis induced by FMDV was es-tablished successfully ,which would lay the foundation for researches of myocarditis mechanism in young cloven-hoofed ani-mals .

A Simple and Rapid Colloidal Gold-based Immunochromatogarpic Strip Test for Detection of FMDV Serotype A / 中国病毒学·英文版

A sandwich format immunochromatographic assay for detecting foot-and-mouth disease virus (FMDV) serotypes was developed. In this rapid test, affinity purified polyclonal antibodies from Guinea pigs which were immunized with sucking-mouse adapted FMD virus (A/AV88(L) strain) were conjugated to colloidal gold beads and used as the capture antibody, and affinity purified polyclonal antibodies from rabbits which were immunized with cell-culture adapted FMD virus (A/CHA/09 strain) were used as detector antibody. On the nitrocellulose membrane of the immunochromatographic strip, the capture antibody was laid on a sample pad, the detector antibody was printed at the test line(T) and goat anti-guinea pigs IgG antibodies were immobilized to the control line(C). The lower detection limit of the test for a FMDV 146S antigen is 11.7ng/ml as determined in serial tests after the strip device was assembled and the assay condition optimization. No cross reactions were found with FMDV serotype C, Swine vesicular disease (SVD), Vesicular stomatiti svirus (VSV) and vesicular exanthema of swine virus (VES) viral antigens with this rapid test. Clinically, the diagnostic sensitivity of this test for FMDV serotypes A was 88.7% which is as same as an indirect-sandwich ELISA. The specificity of this strip test was 98.2% and is comparable to the 98.7% obtained with indirect-sandwich ELISA. This rapid strip test is simple, easy and fast for clinical testing on field sites;no special instruments and skills are required, and the result can be obtained within 15 min. To our knowledge, this is the first rapid immunochromatogarpic assay for serotype A of FMDV.

An ELISA Based on a Truncated Soluble ORF2 Protein for the Detection of PCV2 Antibodies in Domestic Pigs / 中国病毒学·英文版

Postweaning multisystemie wasting syndrome (PMWS) is an important swine disease that is closely associated with porcine circovirus type 2 (PCV2). The capsid protein (Cap protein) is a major structural protein that has at least three immunoreactive regions, and it can be a suitable candidate antigen for detecting the specific antibodies of a PCV2 infection. In the present study, an indirect enzyme-linked immunosorbent assay (TcELISA)based on a truncated soluble Cap protein produced in Escherichia coli (E.coli) was established and validated for the diagnostic PCV2 antibodies in swine. The TcELISA was validated by comparison with an indirect immunofluorescence assay (IIFA). The diagnostic sensitivity (DSN), specificity (DSP), and accuracy of the TcELISA were 88.6%, 90.7% and 89.4%, respectively. The agreement rate was 89.38% between results obtained with TcELISA and IIFA on 113 field sera. A cross-reactivity assay showed that the method was PCV2-specific by comparison with other sera of viral disease. Therefore ,the TcELISA will be helpful for the development of a reliable serology diagnostic test for large scale detection of PCV2 antibodies and for the evaluation of vaccine against PCV2 in swine.

Renaturation, purification and antigenicity identification of recombinant protein of Cysticercus cellulosae expressed in Escherichia coli / 生物工程学报

To obtain the recombinant 18 kD protein with high purity and normal bioactivity of Cysticercus cellulosae (rCE18), E. coli cells with the rCE18 were disrupted ultra-sonically, and the inclusion bodies were washed with a solution containing 0.2% deoxycholic acid sodium (DOC)and 2% DOC, respectively. Then they were denatured with 0.9% sodium lauroyl sarcosine (SKL) followed by dialysis and gel filtration to refold and purify the target protein. At the same time, this method was compared with GST-FF affinity chromatography and recovering from SDS-PAGE gel. Biological activity of purified rCE18 was analyzed with indirect ELISA, and the purity of the products was identified using SDS-PAGE. The purity of refolded inclusion bodies exceeded 60% and the total recovery of activated protein rCE18 was about 41.3%. The specificity of rCE18 reached up to 97.2% using indirect ELISA. An effective way for purifying and refolding rCE18 expressed in E. coli as inclusion bodies was established, rCE18 with higher purity and activity was obtained, which has the potential for developing diagnosis methods of porcine cysticercosis.

Progress of model organism genome / 生物医学工程学杂志

This paper presents a description of the rules of construction and function of genome as well as evolutional relationship between organisms, and opens out the essence of life through introducing the progress in genome of model organism. The other purpose of this review is to highlight the status and function of model organism in the research of comparing genomics so as to provide the model of cycle for researches into high creature life, especially human beings life.

Screening of cDNA Clone for Putative RNA Polymerase Subunit of Cysticercus cellulosae / 中国寄生虫学与寄生虫病杂志

Objective To obtain related genes of Cysticercus cellulosae from spliced leader (SL) cDNA library. Methods Spliced leader library of Cysticercus cellulosae was constructed using SL specific primer and oligo (dT)15 with M13M4 primer, and positive clones were then screened randomly, identified with enzyme restriction, followed by sequencing and homologous analysis. Results The amino acid sequence, encoded by the positive clone with a poly (A) 22 tail and a complete open reading frame (ORF), was with homology of RNA polymerase subunit genes of human, B. napus, fission yeast, A. thaliana, C. elegans and fruit fly up to 71.6%. Conclusion The protein, RNA polymerase subunit encoded putatively by the clone, is high conservative in different species.

Application of Filamentous Phage Display Technology in Parasitology / 中国寄生虫学与寄生虫病杂志

This review focuses on the application of phage display technology in the prevention,diagnosis and treatment of parasitic diseases. It covers: ① an introduction of phage display technology,filamentous phage and the advantage of carrier. ② construction of phage antibody libraries of parasites,epitope mapping and mimotope,and their potential application in the development of novel diagnostic reagents and vaccines.