Construction of a cDNA library for Sparganum mansoni and screening of diagnostic antigen cadidates / 中国血吸虫病防治杂志

Objective To construct a cDNA library of Sparganum mansoni and immunoscreen antigen candidates for immunodiagnosis of sparganosis mansoni. Methods Total RNA was extracted from S. mansoni, and reversely transcribed into cDNA, which was ligated into the phage vector. These recombinant vectors were packaged in vitro to construct the SMART cDNA library of S. mansoni. Then, the cDNA library was immunoscreened with sera from patients with sparganosis mansoni to yield positive clones. The inserted fragments of positive clones were sequenced and subjected to homology analyses, and the structure and functions of the coding proteins were predicted. Results The SMATR cDNA library of S. mansoni was successfully constructed. The titer of the cDNA library was 6.25 × 106 pfu/mL, with a recombinant efficiency of 100%, and the mean length of the inserted fragments in the library was larger than 1 100 bp. A total of 12 positive clones were obtained by immunoscreening, and were categorized into Sm-I (Sm60-1), Sm-II (Sm58-1), Sm-III (Sm20-1) and Sm-IV (Sm22-3), with 1 134, 1 063, 883 bp and 969 bp long inserted fragments. Their coding proteins were highly homologous with the Spirometra erinaceieuropaei antigenic polypeptide, cytoplasmic antigen, ribosomal protein S4-like protein and unnamed protein product, respectively. Conclusions A SMART cDNA library of S. mansoni has been successfully constructed and 4 categories of positive clones have been identified, which provides a basis for further studies on diagnostic antigens for sparganosis mansoni.

Construction and immunoscreening of cDNA library of Armillifer agkistrodontis nymphs / 中国地方病学杂志

Objective To construct cDNA entry library and cDNA expression library of Armillifer agkistrodontis (A.) nymphs and make a preliminary immunoscreening for the cDNA expression library.Methods The nymphs were collected from the Kunming mice infected experimentally with A.agkistrodontis eggs and the total RNA were extracted from the nymphs using TRIzol Reagent.After purifying the mRNA,the synthesized cDNAs were cloned into the donor vector pDONR222 by BP reaction of Gateway technology and the recombinants were transformed into the DH10B cells by electroporation,the cDNA entry library was obtained.Next,the expression vector pDEST17 was ligated with entry clones by LR reaction,and the recombinants were transformed into the BL21 (DE3) cells.Hence,the cDNA expression library was constructed.Then,the expression library was immunoscreened with the mixed sera of mice infected with A.agkistrodontis,and the insertions of positive clones were sequenced.After that,the open reading frame(ORF) of positive slone sequence,the homology of the screened genes and their encoded proteins were analyzed by Finder and BLAST (basic local alignment search tool) program of National Center of Biotechnology Information(NCBI),and the discovered new genes were submitted into the GenBank.Besides,the physico-chemical properties,secondary structure and B cell epitopes of encoded proteins were also analyzed by bioinformatics software.Results The average titer and total clones of the cDNA entry library were 1.45 × 105 CFU/ml(colony-forming unit,CFU) and 1.74 × 106 CFU,respectively,and the range of fragment length of the inserted cDNA was between 0.2-4.0 kb,with an average of 1.4 kb.The total clones of cDNA expression library were 1.00 × 105 CFU,and the fragment length of the inserted cDNA was between 0.3-2.2 kb,with an average of 1.0 kb.Five positive clones,coded S1,S5,A1,D1 and F1,respectively,were obtained through preliminary immunoscreening.The sequence and homology of the five positive clones were sequenced and analyzed by BLAST program.No significant similarities were found in pentastomida species,which meant that they were all novel genes of A.agkistrodontis.The gene sequences were submitted to GenBank,with the accession number from JQ180451 to JQ180455.Also,results obtained by bioinformatics software showed that the predictive encoding proteins were all potential to be valuable recombinant diagnostic antigens.Conclusions The cDNA library of A.agkistrodontis nymphs is successfully constructed,and five new genes of A.agkistrodontis are discovered.The establishment of cDNA library and the discovery of the new genes will lay a foundation for further studying the gene functions and screening the immunodiagnostic antigens.

Expression and Characterization of alpha-Methylacyl CoA Racemase from Anisakis simplex Larvae

Larval excretory-secretory products of Anisakis simplex are known to cause allergic reactions in humans. A cDNA library of A. simplex 3rd-stage larvae (L3) was immunoscreened with polyclonal rabbit serum raised against A. simplex L3 excretory-secretory products to identify an antigen that elicits the immune response. One cDNA clone, designated as alpha-methylacyl CoA racemase (Amacr) contained a 1,412 bp cDNA transcript with a single open reading frame that encoded 418 amino acids. A. simplex Amacr showed a high degree of homology compared to Amacr orthologs from other species. Amacr mRNA was highly and constitutively expressed regardless of temperature (10-40degrees C) and time (24-48 hr). Immunohistochemical analysis revealed that Amacr was expressed mainly in the ventriculus of A. simplex larvae. The Amacr protein produced in large quantities from the ventriculus is probably responsible for many functions in the development and growth of A. simplex larvae.

Identification of Antigenic Proteins in Trichomonas vaginalis

Trichomoniasis is a sexually transmitted disease due to infection with Trichomonas vaginalis, and it can cause serious consequences for women's health. To study the virulence factors of this pathogen, T. vaginalis surface proteins were investigated using polyclonal antibodies specific to the membrane fractions of T. vaginalis. The T. vaginalis expression library was constructed by cloning the cDNA derived from mRNA of T. vaginalis into a phage lambda Uni-ZAP XR vector, and then used for immunoscreening with the anti-membrane proteins of T. vaginalis antibodies. The immunoreactive proteins identified included adhesion protein AP65-1, alpha-actinin, kinesin-associated protein, teneurin, and 2 independent hypothetical proteins. Immunofluorescence assays showed that AP65-1, one of the identified immunogenic clones, is prevalent in the whole body of T. vaginalis. This study led us to identify T. vaginalis proteins which may stimulate immune responses by human cells.

Characterization of a clone from an adult worm cDNA library selected with anti-Schistosoma mansoni human antibodies dissociated from immune complexes: a preliminary report

Considering the scarcity of defined antigens, actually useful and reliable for use in the field studies, we propose an alternative method for selection of cDNA clones with potential use in the diagnosis of schistosomiasis. Human antibodies specific to a protein fraction of 31/32 kDa (Sm31/32), dissociated from immune complexes, are used for screening of clones from an adult worm cDNA library. Partial sequencing of five clones, selected through this strategy, showed to be related to Schistosoma mansoni: two were identified as homologous to heat shock protein 70, one to glutathione S-transferase, one to homeodomain protein, and one to a previously described EST (expressed sequence tag) of S. mansoni. This last clone was the most consistently reactive during the screening process with the anti-Sm31/32 antibodies dissociated from the immune complexes. The complete sequence of this clone was obtained and the translation data yielded only one ORF (open reading frame) that code for a protein with 57 amino acids. Based on this amino acid sequence two peptides were chemically synthesized and evaluated separately against a pool of serum samples from schistosomiasis patients and non-schistosomiasis individuals. Both peptides showed strong reactivity only against the positive pool, suggesting that these peptides may be useful as antigens for the diagnosis of schistosomiasis mansoni.

Considerando a escassez de antígenos quimicamente definidos, realmente úteis e confiáveis para aplicação na soroepidemiologia da esquistossomose em larga escala, foi proposto, neste trabalho, um método alternativo para a seleção de clones de cDNA que expressam proteínas com putativo potencial diagnóstico na esquistossomose. Empregando anticorpos específicos contra uma fração proteica de 31/32 kDa (Sm31/32), purificados através da dissociação de imunocomplexos, foram selecionados cinco clones de cDNA a partir de genoteca de verme adulto de Schistosoma mansoni. O seqüenciamento parcial destes clones demonstrou que todos eram relacionados ao S. mansoni: dois apresentaram homologia com a proteína de choque térmico de 70 kDa e os demais com glutationa S-transferase, "homeodomain protein" e uma etiqueta de seqüência expressa (EST). Este último foi o clone que melhor reagiu, durante o processo de seleção, com os anticorpos anti-Sm31/32 dissociados de imunocomplexos. Baseado na seqüência de aminoácidos deste clone, dois peptídeos foram quimicamente sintetizados e analisados separadamente frente a misturas de soros de indivíduos normais e de pacientes com esquistossomose mansoni. Ambos os peptídeos demonstraram uma intensa reatividade somente contra a mistura de soros positivos, sugerindo que estes peptídeos podem ser úteis como antígenos para o diagnóstico da esquistossomose mansoni.

Construction of cDNA library of the treated Changliver cell and quality analysis / 新乡医学院学报

Objective To construct cDNA library of the treated Changliver cell by switching mechanism at 5′ end of RNA transcript (SMART) technique and analyze its quality.Methods cDNA of Changliver cell was aquired with reverse transcription polymerase chain reaction (RT-PCR) and long-distance PCR (LD-PCR),then the cDNA library was constructed with SMART cDNA library construction kit.Results Through testing,the high quality cDNA library containing full length cDNA of Changliver cell had been constructed.The titer of the amplified cDNA library was 4.5 × 1010 pfu*ml-1 and the average exogenous inserts of the recombinants was 1.5 kb.Conclusion These results suggest that the Changliver cell cDNA library has a high quality and lays a solid foundation for researching on Changliver cell and screening

Immunoscreening and Sequence Analysis of a cDNA Library of Adult Trichinella spiralis / 中国寄生虫学与寄生虫病杂志

Objective To obtain an antigenic gene of adult Trichinella spiralis. Methods cDNA library of the adult Trichinella spiralis was screened using the sera of immunized and infected rabbits. The gene sequence was analyzed by DNAstar software and GenBank database. Results Nine positive clones were identified by immunoscreening. The clone Ts87 was sequenced and a cDNA with 1 172 bp full length was obtained using 5′ RACE technique, encoding 347 amino acids. Some possible antigen epitopes were predicted. Conclusion A novel antigenic gene of Trichinella spiralis was obtained.

Immunoscreening of schistosomulum cDNA library of Schistosoma japonicum and preliminary identification / 中国血吸虫病防治杂志

Objective To obtain genes encoding the novel molecules for diagnosis of schistosomiasis. Methods The cDNA library of Schistosoma japonicum (Sj) schistosomula of day 15 post-infection was screened with positive patients sera,and the inserts of positive clones were sequenced. Then the sequences were compared with all sequences in GenBank database by Internet. The positive clones were analyzed by the software in bioinformatics. Results After three rounds of screening,15 positive clones were obtained,and among them 11 clones had the meaningful sequences,in which 5 genes coding for Sj mitochondrion,1 gene coding for Sj myosin and the others were SjCHGC05315,SjCHGC01371,SjCHGC04782,SjCHGC05166,SjCHGC09769,respectively. Conclusion Immunological screening by using positive patients sera can be used to discover Sj antigen genes with a potential value for diagnosis.

Immunoscreening of Schistosomulum cDNA Library of Schistosoma japonicum and Preliminary Identification of Membrane-AssociatedProtein Abundant in Tegument / 中国寄生虫学与寄生虫病杂志

Objective To obtain genes encoding the novel molecules for diagnosis of schistosomiasis.Methods Juvenile S.japonicum cDNA library was immunoscreened to obtain positive clones.By DNA sequencing and sequence analysis,the target gene was amplified by PCR and subcloned into prokaryotic plasmid pET28a.The recombinant plasmid was transformed into E.coli BL21 followed by expression of the protein induced by IPTG.The protein was identified by Western blotting.Results 34 positive clones were obtained,24 of which were chosen to be sequenced,13 of which were Sj22600 gene.The protein were recognized with sera of infected rabbits and patients with acute and chronic schistosomiasis by Western blotting.Conclusion The gene coding for Sj22600 membrane protein was screened with high frequency in the cDNA library.The E.coli BL21 transformed with the recombinant plasmid can express the fusion protein,which shows immunoactivity.

GENOMIC CLONING OF FASCIOLA HEPATICA SECRETORY ANTIGENS IN ESCHERICHIA COLI / 中国寄生虫学与寄生虫病杂志

pFH23. These studies provide the possibility of further research on the expression of recombinant antigenic genes, the immunity of their expressed products and the protection of animals.

Construction of cDNA Expression Library of Unfed Female Haemaphysalis longicornis and Immuno-Screening / 中国寄生虫学与寄生虫病杂志

Objective To construct a cDNA expression library from unfed female tick Haemaphysalis longicornis for screening and cloning potential antigenic genes.Methods Total RNA was isolated from unfed female ticks,mRNA was purified and a library of oligo(dT)-primed cDNA with added directional EcoR Ⅰ/Hind Ⅲ linkers was constructed from the purified mRNA.The constructed cDNA was ligated to the EcoRⅠ/HindⅢ arms of the ?SCREEN vector.Pure phage stocks were harvested by plaque purification and converted to plasmid subclones by plating phage on host strain BM25.8.Recombinant plasmids that were subcloned to E.coli BM25.8 were isolated and transformed into E.coli JM109.Recombinant plasmids abstracted from JM109 were identified by PCR and sequencing.Rusults The recombinant phage DNA was packaged by using phage-marker packaging extracts,resulting in a primary cDNA library with a size of 1.8?106 pfu.Data showed 100% of the library were recombinant and the titer of the amplified library was 2.4?109 pfu/ml.Forty-two clones of encoding immunodominant antigens were obtained from the cDNA library.Sequence analysis revealed 12 unique cDNA sequences and the encoded putative proteins showed similarities to H.longicornis tropomyosin mRNA,Rhipicephalus annulatus unknown larval protein mRNA,chromosome 2R of Drosophila melanogaster,mitochondrial DNA of H.flava,clones HqL09 unkown mRNA and Hq05 mRNA of H.qinghaiensis,and myosin alkali light chain protein mRNA.Conclusion The cDNA expression library from unfed female H.longicornis was successfully constructed and screening of protective genes may provide candidate antigens of the tick.