Acute hepatopancreatic necrosis disease (AHPND) caused by Vibrio species is one of the most common bacterial diseases carrying the plasmid encoding pirA vp and pirB vp toxin genes that cause lethargic and anorexic effect on infected shrimps due to induced necrosis in the hepatopancreas. This study demonstrates the use of gold nanoparticles (AuNPs) coupled with specific thiol probe for the detection of pirA vp toxin gene causing AHPND. Detection of pirA vp toxin gene using thiol probe was validated using colorimetric assay. The validation results showed that the developed Deoxyribonucleic acid (DNA)-based AuNPs detection was specific and highly sensitive to detect the pirA vp toxin gene at 20 fg/ul of shrimp genomic DNA. This nanotech-based polymerase chain reaction (PCR) amplification-free protocol can serve as a new means of diagnostic strategy for AHPND detection in aquaculture industry. Furthermore, the method provides accurate and timely detection on field setting which can help to reduce mass mortality and drastic economic losses on aquaculture.

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Objective:Major histocompatibility complex (MHC) is a set of molecular proteins on the surface of antigen presenting cells encoded by a large gene family which are important parts of the immune system. This study was conducted to convey information on the genetic characteristics of the MHC II DRB3 gene in riverine and swamp buffaloes.Materials and Methods:Characterization of MHC II DRB3 gene was carried out using polymerase chain reaction (PCR)-based assay. Thirty-milliliter milk samples were collected from 10 swamp-type and 10 riverine-type buffaloes. RNA from milk samples were extracted using Trizol and then followed by reverse transcription-PCR (RT-PCR).Results:The phylogenetic analysis with 1,000 bootstrap replications clearly showed complex parsimony in MHC II DRB3 gene between 10 riverine- and 10 swamp-type but also confirmed that the samples are similar to Bubalus bubalis. Aligned sequences of the 20 water buffaloes were compared with three other ruminants (Bos taurus, Ovis aries, and Capra hircus) and non-ruminant (Sus scrofa) that serve as an outgroup. MHC sequences from GenBank show that there was an average of 705 identical pairs, with 22 transitional pairs and 30 transversional pairs with a ratio of 0.7.Conclusion:Based on the molecular data, the current study conforms to other works of literature that this gene is highly polymorphic which can be due to its function in the immune responsiveness and disease resistance. Further study on the immunological response of MHC II DRB3 to infection may elucidate its underlying function and role in the protection against specific disease of animals.