Red seabream iridovirus (RSIV), a member of the Iridoviridae family, is the causative pathogen of some of the most explosive epidemics of emerging viral diseases in many Asian countries, leading to huge economic losses in aquaculture. Rapid molecular detection for surveillance or diagnosis has been a critical component in reducing the prevalence of RSIV infection. In the present study, a novel and highly specific loop-mediated isothermal amplification (LAMP) assay for the sensitive and rapid detection of RSIV infection in fishes was developed. Using a set of synthesized primers matching a specific region of the RSIV genome (GenBank accession no.: AB666336.1), the efficiency and specificity of the LAMP assay were optimized in terms of the reaction temperature and DNA polymerase concentration, as they are the main determinants of the sensitivity and specificity of the LAMP assay. In particular, we demonstrated that our assay could be applied to efficiently detect RSIV infection in red sea bream. Our results provide a simple and convenient method for the detection of viral infection in aquatic organisms.

요 약 망그로브 생태계는 수생태계로 유입되는 중금속을 받아들이는 기능을 가지고 있다. 중금속에 오염된 퇴적물 에 노출됨에도 불구하고 망그로브는 중금속에 내성을 가지고 있다. 이 연구에서 우리는 망그로브로부터 중금속 저항 성 관련 유전자를 클로닝하고, 중금속 노출에 유전자 발현 변화를 분석하였다. 미크로네시아 축라군의 웨노섬에서 채 취한 Rhizophora stylosa의 잎과 뿌리조직으로부터 CTAB 방법을 이용하여 RNA를 분리하였고, gene specific primers 를 이용하여 phytochelatin synthase 1(PCS1) 유전자를 클로닝하였다. R. stylosa 태생종자를 100 ppb의 Cd과 10 ppbAbstract The mangrove ecosystems have the capacity to act as a sink of heavy metals entering aquatic ecosystems. Despite their potential exposure to metal contaminated sediments, mangroves appear to be highly tolerant to heavy metals. In this study, we cloned metal tolerance gene from mangrove plant. Using CTAB method, RNA were isolated from leaves and root tissue of Rhizophora stylosa habitated at Weno island in Micronesia Chuuk lagoon using CTAB method and phytochelatin synthase 1 (PCS1) gene was cloned using gene specific primers. Expression of PCS1 gene was increased 1.91 fold and 2.72 fold in mangrove propagules exposed to 100 ppb Cd and 10 ppb Cu, respectively. These results indicate that expression of PCS1 gene are promising tools for health assessment of mangrove ecosystem.

The red seabream iridovirus (RSIV), which belongs to the iridoviridae, causes infectious fish diseases in many Asian countries, leading to considerable economic losses to the aquaculture industry. Using the yeast surface display (YSD) technique, a new experimental system was recently developed for the detection and identification of a variety of marine viruses. In this study, a coat protein gene of RSIV was synthesized based on the nucleotide sequence database and subcloned into the yeast expression vector, pCTCON2. The expression of viral coat proteins in the yeast strain, EBY100, was detected by flow cytometry and Western blot analysis. Finally, they were isolated from the yeast surface through a treatment with β-mercaptoethanol. The data suggests that the YSD system can be a useful method for acquiring coating proteins of marine viruses.

Changes of phenolics, antioxidant activities and fatty acid contents were determined in the mangrove plant exposed to Cu, Ni and Cd. Propagules of Rhizophora mangle were cultured for 12 weeks under the Cu (0.01 and 1 ppm), Ni (0.1 and 10 oom) and Cd (0.1 and 10 ppm) stresses. In comparison with control, morphological changes of mangrove root were not observed in 12 weeks. Significant changes of phenolics were not detected and antioxidant activities were dramatically increased in the metal-treated mangroves. Fatty acid, C14:1, C15:1 and C18:3n-6, contents were changed in the all of tested propagules. These results shows that DPPH radical scavenging assay and determination of fatty acid contents could be useful biomarkers for diagnosing responses of mangrove plant under heavy metal stress.