본 연구에서는 해상가두리 양식장에서 북방전복과 둥근전복속 교잡종(왕전복♀*둥근전복♂)의 생물지표를 분석하여 교잡육종의 결과를 평가하고자 하였다. 생존율은 북방전복과 유사하였 으나, 성장(각장)은 교잡종에서 약 10% 빠른 것으로 분석되었다. 패각의 호흡공 기형율은 교잡 종이 북방전복보다 약 6% 낮았으며, 패각 함몰 및 부식율은 교잡종이 약 15% 낮았다. 생화학 적 조성에서는 조단백질의 경우 교잡종에서 약 3.1% 높았으며, 이를 제외한 나머지에서 유사 한 값을 나타냈다. 소화, 흡수 및 해독기능을 수행하는 간췌장의 조직학적 평가에서는 교잡종 에서 좋은 결과를 보였다. 이러한 결과로 보아 둥근전복속 교잡종은 추후 양식 환경에 접목 하였을 때 높은 양식 생산력을 가질 것으로 판단된다.

본 연구에서는 한국 남해안의 해상가두리에서 북방전복 Haliotis discus hannai 부착생물의 종류 와 밀도에 관한 자료의 축적과 부착생물 제거에 따른 영향을 평가하고자 하였다. 해상가두리에 서 북방전복의 부착생물은 굴, 태형동물, 따개비가 우점하였으며, 이들의 평균 부착생물 면적비 는 약 57.5%였다. 성장률과 간췌장의 건강도는 대조구에 비해 부착생물 제거구에서 좋은 결과 를 보였다. 따라서 전복의 부착생물 제거는 개체의 성장과 출하 시 상품성 향상을 위해 필요한 것으로 판단된다.

본 연구는 우리나라 해안에서 널리 서식 중인 해양 자원 중 하나인 전복(Haliotis discus hannai) 의 차세대염기서열분석 데이터 기반으로 선별한 신규 펩타이드의 항암 활성을 평가한 연구이 다. 펩타이드의 항암 활성은 교모세포종 세포주인 SNU-489에서 농도 의존적으로 처리 시간에 비례하여 증가하였으며, 200 μM로 48시간 처리하였을 때 암 세포 사멸율이 67%로 가장 높게 나타났다. 반면 정상 세포인 HaCaT에서 가장 높은 세포 사멸율은 18%로 농도 의존적이었으나 처리 시간과는 무관하였다. 또한 신규 펩타이드의 항암 메커니즘 과정을 밝히기 위해 세포자 멸괴사(Necroptosis) 관련 유전자의 발현 변화를 qRT-PCR 방법을 통해 검증하였다. RIPK3는 신 규 펩타이드 처리군에서 200 μM 처리 시 9배 이상 발현 증가, MLKL는 100 μM 처리군에서 대조군 대비 2배 이상 유의미하게 발현이 증가되었다. 이러한 결과로 미루어 볼 때, 전복 유래 신규 펩타이드는 암 세포 특이적으로 세포 독성을 가지며, 세포자멸괴사 메커니즘을 통해 암 세포 사멸을 일으키는 것으로 추측되므로 신규 펩타이드가 추후 교모세포종 치료제의 후보 물질로 활용될 수 있을 것으로 사료된다.

북방전복 Haliotis discus hannai 웅성생식세포의 분화과정과 정자의 형태를 미세구조적으로 기 재하였다. 정자의 분화과정은 정원세포기, 정모세포기, 정세포기 및 정자기의 4단계로 구분하였 다. 정원세포기에서 정모세포기로의 분화과정은 형태학적 변화가 크지 않았다. 그러나 정자변 태과정 동안 염색질 응축, 핵의 형태 변화, 첨체와 중편 및 편모 형성 등의 급격한 형태학적 변 화를 나타냈다. 북방전복의 정자는 두부, 중편 및 미부로 구성되며, 두부의 길이는 약 5.3 μm로 전자밀도가 높은 핵과 총알형의 첨체로 이루어져 있었다. 중편은 기저체와 미토콘드리아로 구 성되어 있었으며, 기저체를 중심으로 5개의 미토콘드리아가 한 층으로 배열되어 있었다. 미부 의 횡단면은 "9+2"의 미세소관 구조를 보였다. 이러한 형태 및 구조적 특징은 북방전복의 정자 는 원시형(primitive type) 정자임을 보여주는 결과이다.

Heat shock proteins (HSPs) are highly conserved cellular proteins that contribute to adaptive responses of organisms to a variety of stressors. In response to stressors, cellular levels of HSPs are increased and play critical roles in protein stability, folding and molecular trafficking. The mRNA expression pattern of two well-known heat shock protein transcripts, HSP70 and HSP90 were studied in two tissues of nerve ganglia, cerebral ganglion and pleuropedal ganglion of Pacific abalone (Haliotis discus hannai). It was observed that both HSP70 and HSP90 transcripts were upregulated under heat stress in both ganglion tissues. Expression level of HSP70 was found higher than HSP90 in both ganglia whereas cerebral ganglion showed higher expression than pleuropedal ganglion. The HSP70 and HSP90 showed higher expression at Day-1 after exposed to heat stress, later decreased at Day-3 and Day-7 onwards. The present result suggested that HSP70 and HSP90 synthesize in nerve ganglion tissues and may provide efficient protection from stress.

Karyotype analysis is a major work in the process of triploid abalone production for the purpose of productivity and quality improvement. However, the metaphase spreads for karyotype analysis have been prepared just from the larvae at trochophore stage, which has restricted the spectrum of sample correction inhibiting more efficient analysis. Here, we investigated the feasibility of preparing metaphase spreads from the larvae at veliger stage that is the next developmental stage of trochophore. For this, diploid and triploid larvae at trochophore and veliger stages from Pacific abalone (Haliotis discus hannai ) were subjected to metaphase spread preparation and its efficiencies were measured and compared each other. As the results, although the efficiencies of metaphase spread preparation were significantly lower in the larvae at veliger stage compared to the ones at trochophore stage regardless of ploidy status, we found that the preparation of metaphase spreads, which showed the clear chromosomal images containing the normal number of chromosomes, was possible from the veliger stage larvae. On the other hands, all larvae used in this study regardless of developmental stage and ploidy did not show colchicine sensitivity. Moreover, no significant difference was observed in cell cycle distribution of the cells comprising larvae between two developmental stages regardless of ploidy status. These suggested that the details of protocol to prepare metaphase spreads from abalone larvae should be optimized depending on its developmental stages. Taken together, we demonstrated the feasibility of preparing metaphase spreads from H. discus hannai veliger stage larvae for karyotype analysis.

The level at which analyses of DNA content might contribute more significantly to the genetic mechanisms of evolution lies in the events of speciation. The object of this study was to investigate the DNA content of abalone (Haliotis discus hannai) and determine the optimal tissue samples for measuring the DNA content of abalone by flowcytometry without fixation. The DNA content (pg/nucleus) of gill tissue (2.5±0.08), which was contaminated with protozoa, was significantly lower than that of muscle tissue (3.2±0.02), mantle tissue (3.2±0.02) (p<0.05), and a standard reference standard, while the DNA contents of muscle tissue and mantle tissue were higher than that of the standard reference. Considering the results of this study, DNA content analysis with flowcytometry is an acute and rapid method by which muscle tissue and mantle tissue are the most appropriate sample for measuring the DNA content of abalone without fixation.

Potential utility of 14 candidate housekeeping genes as normalization reference for RT-qPCR analysis with developmental samples (fertilized eggs to late veliger larvae) in Pacific abalone Haliotis discus hannai was evaluated using four different statistical algorithms (geNorm, NormFinder, BestKeeper and comparative ΔCT method). Different algorithms identified different genes as the best candidates, and geometric mean-based final ranking from the most to the least stable expression was as follow: RPL5, RPL4, RPS18, RPL8, RPL7, UBE2, RPL7A, GAPDH, RPL36, PPIB, EF1A, ACTB and B-TU. The findings were further validated via relative quantification of metallothionein (MT) transcripts using the stable and unstable reference genes, and expression levels of MT were greatly influenced according to the choice of reference genes. In overall, our data suggest that RPL5 and RPS18, either singly or in combination, are appropriate for normalizing gene expression in developmental samples of this abalone species, whereas ACTB, B-TU and EF1A are less stable and not recommended. In addition, our findings propose that standard deviations in geometric ranking as well as geometric mean itself should also be taken into account for the final selection of reference gene(s). This study could be a useful basis to facilitate the generation of accurate and reliable RT-qPCR data with developmental samples in this abalone species.

Recently, mass mortality of the young abalone Haliotis discus hannai has occurred in commercial seed production farms in Korea. The mortality rate was above 50% of the total cultured organisms in the farm, and the shell length of the moribund organisms was about 3cm. The mortal phenomenon was that the young abalones were weakly scattered on the bottom of the pond from the attachment matrix, or that they could not be moved back to their normal positions. The diseased farmed Pacific abalone had abdominal edema. From the edema in the moribund individuals, three bacterial strains were isolated and all the strains were identified as Vibrio harveyi. These strains were compared with thirty six strains isolated from the fish. The results was that the Vibrio harveyi from the fish were sorted into genogroup A or B; however, the three strains of the diseased farmed Pacific abalone were sorted into genogroup A and the new genogroup C. The identical mortality and pathological symptoms of the naturally infected organisms were reproduced by artificial infection with WA AG-1 and WA CS-5 strains. The LD50 of WA AG-1 and WA CS-5 were each 1.0×103 cfu animal-1 and 1.7×104 cfu animal-1.

In abalones, interspecific hybridization has been suggested as a possible means to increase production and desired traits for the industry. In Korea, Haliotis gigantea is considered a species with a larger size and higher temperature tolerance than H. discus hannai. However, H. discus hannai is considered the most valuable and popular fishery resource due to its better acceptance and higher market prices. Thus, viable interspecific hybrids have been produced by artificial inseminating H. gigantea eggs with H. discus hannai sperm. However, the reciprocal hybrid cross was not successful. In this study, the hybridity and the growth and thermal tolerance performance of the interspecific hybrids were examined. A combination of various assays revealed maximum growth occurrence at 21℃ and the higher growth rate in the hybrids than that of H. discus hannai parent. In addition, the growth and survival at high-temperature (28℃) of the hybrids was equivalent to that of the highly tolerant H. gigantea parent, suggesting new possibilities to overcome the mass mortality in H. discus hannai during high temperature periods of summer season in Korea. Furthermore, the induced interspecific hybrid status was confirmed by the presence of species-specific bands for each parental species of the random amplified polymorphic DNA (RAPD) profiles using universal rice primer (URP), which could be used as speciesspecific markers to distinguish the hybrids and their parental species.