Combination of multiplex reverse transcription recombinase polymerase amplification assay and capillary electrophoresis provides high sensitive and high-throughput simultaneous detection of avian influenza virus subtypes

The pandemic of avian influenza viruses (AIVs) in Asia has caused enormous economic loss in poultry industry and human health threat, especially clade 2.3.4.4 H5 and H7 subtypes in recent years. The endemic chicken H6 virus in Taiwan has also brought about human and dog infections. Since wild waterfowls is the major AIV reservoir, it is important to monitor the diversified subtypes in wildfowl flocks in early stage to prevent viral reassortment and transmission. To develop a more efficient and sensitive approach is a key issue in epidemic control. In this study, we integrate multiplex reverse transcription recombinase polymerase amplification (RT-RPA) and capillary electrophoresis (CE) for high-throughput detection and differentiation of AIVs in wild waterfowls in Taiwan. Four viral genes were detected simultaneously, including nucleoprotein (NP) gene of all AIVs, hemagglutinin (HA) gene of clade 2.3.4.4 H5, H6 and H7 subtypes. The detection limit of the developed detection system could achieve as low as one copy number for each of the four viral gene targets. Sixty wild waterfowl field samples were tested and all of the four gene signals were unambiguously identified within 6 h, including the initial sample processing and the final CE data analysis.The results indicated that multiplex RT-RPA combined with CE was an excellent alternative for instant simultaneous AIV detection and subtype differentiation. The high efficiency and sensitivity of the proposed method could greatly assist in wild bird monitoring and epidemic control of poultry.

Development of an oligonucleotide microarray for simultaneous detection of two canine MDR1 genotypes and association between genotypes and chemotherapy side effects

Canine MDR1 gene mutations produce translated P-glycoprotein, an active drug efflux transporter, resulting in dysfunction or over-expression. The 4-base deletion at exon 4 of MDR1 at nucleotide position 230 (nt230[del4]) in exon 4 makes P-glycoprotein lose function, leading to drug accumulation and toxicity. The G allele of the c.-6-180T>G variation in intron 1 of MDR1 (single nucleotide polymorphism [SNP] 180) causes P-glycoprotein over-expression, making epileptic dogs resistant to phenobarbital treatment. Both of these mutations are reported to be common in collies. This study develops a more efficient method to detect these two mutations simultaneously, and clarifies the genotype association with the side effects of chemotherapy. Genotype distribution in Taiwan was also investigated. An oligonucleotide microarray was successfully developed for the detection of both genotypes and was applied to clinical samples. No 4-base deletion mutant allele was detected in dogs in Taiwan. However, the G allele variation of SNP 180 was spread across all dog breeds, not only in collies. The chemotherapy adverse effect percentages of the SNP 180 T/T, T/G, and G/G genotypes were 16.7%, 6.3%, and 0%, respectively. This study describes an efficient way for MDR1 gene mutation detection, clarifying genotype distribution, and the association with chemotherapy.

The bioactivity of teleost IL-6: IL-6 protein in orange-spotted grouper (Epinephelus coioides) induces Th2 cell differentiation pathway and antibody production.

Interleukin 6 (IL-6) is a protein secreted by T cells and macrophages and plays an important role in immune response. IL-6 regulates the proliferation and differentiation of T cells, and elicits immunoglobulin production in B cells. In this study, the cDNA il-6 (gil-6) sequence of the orange spotted grouper (Epinephelus coioides) was obtained. The deduced IL-6 (gIL-6) protein comprised 223 amino acids, the sequence shared approximately 30% similarity with mammalian IL-6, and between 47% and 69% similarity with other available teleost IL-6. The protein comprises the signal peptide, the IL-6 family signature, and conserved amino acid residues found in IL-6 sequences of other teleost. In order to understand the bioactivity and influence of gIL-6 on humoral immune response, recombinant gIL-6 (rgIL-6) synthesized by prokaryotes was injected into orange spotted groupers, and the immune-related gene expression at various times in various organs was observed. Our results revealed that the Th1 specific transcription factor t-bet was down-regulated and Th2 specific transcription factors gata3, and c-maf were up-regulated in immune organs, following IL-6 stimulation. Additionally, higher levels of igm mRNA and translated protein were detected in rgIL-6 stimulated fish. These results indicate that IL-6 in groupers regulates the differentiation of naїve T helper cells into Th2 cells and elicits the production of antibodies.

Identification of antigens for the development of a subunit vaccine against Photobacterium damselae ssp. piscicida.

Photobacterium damselae ssp. piscicida (Ph.d.p.), the causative agent of photobacteriosis, is among the most important pathogens affecting finfish aquaculture globally. With the emergence of recombinant technology, subunit vaccines have been actively pursued, but mostly for viral diseases. Bacterial subunit vaccines are more difficult to develop since the bacterial genome is more complex, with numerous candidate antigens, leading to a lengthy and laborious screening process. Immunoproteomics, using western blotting on protein analyzed with 2DE and LC-MS/MS to isolate immune-reactive proteins and acquire amino acid sequences, followed by recombinant technology to clone the candidate gene, identified eight candidate antigens from Ph.d.p., which have been cloned and expressed in Escherichia coli BL21(DE3). These proteins were purified and used as antigens in an efficacy trial. Three, rHSP60, rENOLASE, and rGAPDH proteins, elicited higher specific antibody titers and stronger protective immunity than the other five and an inactivated Ph.d.p. whole bacterial vaccine. These three antigens may be candidates for the development of a subunit vaccine against Ph.d.p.