Biology subjects

Itsathitphaisarn, O.

Publications and source records attributed to Itsathitphaisarn, O..

2 recordsLinked to original sources

bioRxiv2026

Shrimp endogenous viral elements (EVE) correlate with survival in white spot syndrome virus (WSSV) challenges

Shrimp and other arthropods are capable of specific, adaptive immune responses to viruses based on viral copy DNA (vcDNA) fragments in the host genome called endogenous viral elements (EVE). These may produce negative sense RNA transcripts leading to an RNA interference (RNAi) defense response against cognate viruses. We first reported high-frequency-read sequences (HFRS) of white spot syndrome virus EVE (named WSSV-EVE 4,6,8) in a WSSV-free breeding stock of whiteleg shrimp (Penaeus vannamei). Here we describe screening for the same HFRS-EVE in a captured giant tiger shrimp (Penaeus monodon) breeding stock, also free of WSSV. WSSV-EVE 4,6,8 was detected in some of the P. monodon stock individuals with positive or negative RNA expression. Eight broodstock individuals were selected for mating in 4 crosses. The offspring from these crosses were grown sufficiently to allow tagging and pleopod sampling for DNA and RNA analysis prior to challenge with WSSV. This allowed for Mendelian analysis of EVE inheritance and for its expression or not in the offspring, together with analysis of their relationships to survival and WSSV infection level after challenge. The results revealed that EVE inheritance was Mendelian, but that their RNA expression or not was independently controlled. In Crosses 1 and 2, all the offspring died and none of them carried 2 or more of the expressed EVE in their parental shrimp. In contrast, 100% of 10 arbitrarily selected surviving shrimp from Cross 3 and 90% from Cross 4 carried and expressed 2 or more of the 3 expressed EVE transmitted from the parental shrimp. These results reveal a potential protocol for development of viral tolerant shrimp stocks.

zoology↗

bioRxiv2021

The false mussels (Mytilopsis leucophaeata) can be mechanical carriers of the shrimp microsporidian Enterocytozoon hepatopenaei (EHP)

Enterocytozoon hepatopenaei (EHP) is an obligate intracellular parasite causing hepatopancreatic microsporidiosis (HPM) in cultivated shrimp in Asian countries. One strategy to control EHP is to identify and eliminate biological reservoir(s) in shrimp ponds. Several marine and brackish-water organisms, including false mussels (Mytilopsis) have been reported to test positive for EHP using polymerase chain reaction (PCR) technology. Thus, we tested samples of commonly found Thai false mussel Mytilopsis leucophaeata from 6 EHP-infected shrimp ponds by PCR for the presence of EHP using the spore wall protein (SWP) gene primers. The mussel samples from all 6 ponds were positive. Subsequent bioassays carried out using naive mussels cohabitated with EHP-infected shrimp gave 100% SWP-PCR positive mussels at 20 days. One batch of such PCR-positive mussels was transferred for cohabitation with naive shrimp and gave 37.5% EHP-positive shrimp within 10 days. Tissue analysis of the EHP-PCR-positive mussels using light microscopy, in situ hybridization analysis for the SWP gene and electron microscopy did not confirm EHP infection. In summary, we obtained no evidence that Mytilopsis leucophaeata was itself infected with EHP. However, it was apparently capable carrying infectious spores for some period after ingestion and serving as a mechanical or passive carrier. The results support previous reports warning of the danger of feeding living or fresh bivalves to broodstock shrimp in hatcheries or shrimp in rearing ponds without prior heating or freezing.

zoology↗