본 연구는 담녹조강 Tetraselmis suecica와 T. tetrathele의 인산염 흡수에 미치는 발광다이오드의 파장의 영향을 조사하였다. 파장은 청색 발광다이오드(LED; 450 nm), 황색 LED(590 nm), 적색 LED(630 nm) 그리고 형광램프(control)이며, 조도는 100 μmol m-2 s-1로 주사하였 다. T. suecica와 T. tetrathele의 최대흡수속도(ρmax)는 적색 LED에서 6.35 pmol cell-1 hr-1와 9.85 pmol cell-1 hr-1로 나타났으며, 반포화농도(Ks)는 9.43 μM와 21.2 μM로 나타났다. 이는 적색 LED 아래에서 T. suecica와 T. tetrathele가 다른 파장보다 영양염에 대한 친화성이 높다는 것으로 의미한다. 따라서 경제성 및 생산성 향상을 위한 Tetraselmis 배양시스템(광배양기)의 최적 광원은 낮은 영양염 상태에서도 높은 생장속도를 보이는 적색 LED가 적합할 것으로 판단된다.

Toll and IMD pathways play an important role in producing antimicrobial peptides (AMPs) through NF-κB in insects. The functions of IκB kinase (IKK) complex regulating the NF-κB signaling cascade have not yet been investigated in Tenebrio model. Here, we identified TmIKK-β (or TmIrd5) which contains 2,112 bp encoding 703 amino acid residues. Domain analysis shows that TmIKK-β contains one Serine/Threonine protein kinases catalytic domain. Developmental expression patterns indicate that TmIKK- β gene was highly expressed in early pupal (P1) and adult (A5) stages. Tissue specific profiles show that TmIKK-β was highly expressed in the integuments in last instar larvae, and fat body and hemocytes in 5 day-old adults. TmIKK-β1 transcripts were strongly induced at 3 and 12 h-post injection of E. coli, and 3 h-post injection of S. aureus or C. albicans in hemocytes. In gut, TmIKK-β transcripts were slightly induced by E. coli (at 6, 9 and 24 h) and C. albicans (at 24 h), while it was not induced by S. aureus challenge. Moreover, it was highly induced at 6 h-post injection of E. coli and then it was gradually decreased in the fat body. To understand the immunological role of TmIKK-β, gene specific RNAi and mortality assay was performed. Depletion of TmIKK-β mRNA leads to increase microbial susceptibility of larvae against E. coli, S. aureus and C. albicans. In addition, induction patterns of fourteen AMP genes in response to microbial challenge was tissue specifically investigated in TmIKK-β–silenced T. molitor larvae. The results suggest that expression of ten AMP genes out of fourteen genes were drastically decreased by TmIKK-β RNAi in fat body, suggesting that TmIKK-β plays an important role in antimicrobial innate immune responses.

It has been well known that IKK-β, -ε and –γ play a pivotal role in IMD pathway. In this study, TmIKK-ε was identified and their functions in countering pathogenic infections were investigated. We identified TmIKK-ε gene which including 2,196 bp nucleotides (encoding 731 amino acid residues). Domain analysis of TmIKK-ε indicates that there is one Serine/Threonine protein kinases catalytic domain. TmIKK-ε gene was highly expressed in 2 day-old pupal stage and the expression was gradually decreased until 1 day-old adults. Then the expression was slightly increased until 4 day-old adult stage. Tissue specific expression of TmIKK-ε mRNA was high in the gut, integuments and hemocytes in last instar larvae, and fat body, Malpighian tubules and testis in 5-daysold adult. In hemocytes, TmIKK-ε was drastically induced by E. coli injection after 3 h and by S. aureus at 3 and 12 h-post injection. In gut, expression level of TmIKK-ε was high at 6 h-post injection of microbial injection. Expression of TmIKK-ε in fat body was drastically induced by E. coli at 3 and 24 h-post injection while it was not significantly induced by S. aureus and C. albicans. To understand the immunological role of TmIKK-ε, gene specific RNAi and mortality assay were performed. TmIKK-ε RNAi caused increased larval mortality against E. coli, not S. aureus and C. albicans. Finally, to investigate the induction patterns of Tenebrio fourteen AMP genes in response TmIKK-ε RNAi, three microorganisms were treated into TmIKK-ε-silenced T. molitor larvae. Nine out of fourteen AMP genes were not induced by microbial challenge in TmIKK-β dsRNA-injected group. Taken together, our results indicate that TmIKK-ε may regulates nine antimicrobial peptide genes in response to microbial challenge in T. molitor fat body.

Autophagy is an important self-eating process to eliminate damaged or unused organelles. We identified nine autophagy-related genes (Atg) including AaAtg-1, -3, -4b, -4d, -5, -6, -8, -12 and -13 from the Asian tiger mosquito, Aedes albopictus. Developmental expression patterns indicate that mRNA levels of AaAtg-1, -3, -4b, -4d, -5, -6, -12 and -13 were highly expressed in egg, whereas expression of AaAtg8 was high in 1stand3rdinstarlarvalstages. TissuespecificexpressionofthesegenesindicatesthatAaAtg1 was highly expressed in thorax and midgut in blood-fed adult female mosquitoes (BF), and head and thorax in sugar fed adult female mosquitoes (SF). Transcript level of AaAtg3 was high in thorax in BF, but head, thorax and Malpighian tubules in SF. AaAtg4b, -4d mRNA levels were significantly high in Malpighian tubules in BF, and head in SF, respectively. AaAtg-5 and -6 transcripts were highly expressed in head in BF, and expression of AaAtg-8 was high in Malpighian tubules in BF. Levels of AaAtg-12 and -13 mRNAs were significantly high in head and midgut in BF. Induction patterns of AaAtg genes against pathogens showed that AaAtg-1, -3, -4b, -8, -12 and -13 were strongly induced at 6 h-post injection of S. aureus, and mRNA levels of AaAtg-1, -3 and -13 were significantly induced by E. coli challenge after 3 h-post injection in SF abdominal carcass. In SF midgut, AaAtg-1, -3, -4b, -4d, -5, -6, -12 and -13 transcripts were drastically induced at 9 h-injection of E. coli and S. aureus, while expression of AaAtg-8 was highly induced by S. aureus and C. albicans at 9 h-post injection. Each AaAtg gene was slightly induced by E. coli, S. aureus or C. albicans at different time points in abdominal carcass in BF. Interestingly, AaAtg-8 was not induced by microbial challenge. While eight other Atg genes except AaAtg-8 were highly influenced by S. aureus at 6 and 9 h-post injection, E. coli at 3 h-post-treatment, and 3, 6, and 9 h-post inoculation. In the future, we will characterize the functional roles of autophagy during mosquito-microbes interaction.

Host defense against pathogen invasion highly relies on immune defense machinery that is controlled by the nuclear factor-κB (NF-κB) of transcription factors. The Toll pathway are well known as an insect innate immune mechanism to protect host itself from invaded pathogens. Basically, in the edible insect, Tenebrio molitor, the Toll pathway is primarily activated by polymeric Lys-type peptidoglycans (PGNs), and components of fungal cell walls, β-1,3-glucan. Based on the current studies, the tremendous study has been focused on recognition and subsequent activation of spätzle in haemolymph, hence, there is a grave gap for intracellular event. Herein, in order to understand intracellular event of Toll signaling pathway, the Dorsal gene were identified. Moreover, domain analyses of TmDorsal2 gene indicate that there are two major domains such as Rel homology domain (RHD), ig-like, plexins, and transcription factors (IPT) domains. Based on the achieved results, TmDorsal2 mRNA was highly expressed in 1-day old pupa. Furthermore, TmDorsal2 was highly expressed in Malpighian tubules and fat body in last instar larvae (LL), and likewise mainly expressed in Malpighian tubules during adult 5-day old period, also the lowest expression of TmDorsal2 was observed in gonads. Moreover, TmDorsal2 mRNA levels after infection with E. coli appreciably went up at 6 and 9h time points. To investigate the effects of TmDorsal2 RNAi on larval susceptibility against various pathogens namely E. coli, S. aureus or C.albicans, dsRNA of TmDorsal2 has been synthesized the larvae dissected after 24h. As a result, TmAttacin1a, 1b and 2, TmDefencine1 and 2, TmTenecin1, 2, 3 and 4, TmCecropin2, TmColeoptericin1 and 2, Thaumatin-like protein 1 and 2 markedly reduced in the gut after injecting all mentioned microbes. In contrast, TmTenecin 2, Thaumatin-like protein 1 and 2 strikingly increased after microbe injection in the fat body. Interestingly, the most AMPs gene expression in whole body experimental case were upregulated. On the horizon, we will investigate effects of TmDorsal1 RNAi on larval susceptibility against various pathogens. Taken together, our studies may aid to understand insect innate immunity.

IKK-γ is an essential protein to form IKK complex which regulate NF-κB. We identified TmIKK-γ (or TmKenny) gene which has 1,521 bp of nucleotides encoding 506 amino acid residues. Domain analysis of TmIKK-γ shows that there are one NF-κB essential modulator (NEMO) domain and a leucine zipper domain. Expression of TmIKK-γ gene was gradually increased from egg to 2-day-old pupal stage, dramatically decreased until 7 day-old pupal stage, and then it was gradually increased. TmIKK-γ transcripts were highly expressed in fat body and hemocytes in late instar larvae and integuments, fat body and Malpighian tubules in 5 day-old adult. TmIKK-γ was drastically induced by E. coli after 3 h challenges and by S. aureus at 3 and 12 h-post injection in hemocytes. TmIKK-γ was not induced by C. albicans although it was significantly induced by E. coli (at 3, 6 and 24 h) and S. aureus (at 9 h) in gut. In fat body, expression of TmIKK-γ was drastically induced by E. coli at 3 and 24 h-post injection while it was not significantly induced by S. aureus and C. albicans. To understand the immunological role of TmIKK-γ, gene specific RNAi and mortality assay was performed. larval mortality against microbial challenge was dramatically increased by TmIKK-γ RNAi. Furthermore, we investigate the tissue specific induction patterns of fourteen AMP genes in response TmIKK-γ dsRNA-treatment. In fat body, ten AMP genes out of fourteen was not significantly induced by microbial challenge in TmIKK-γ dsRNA-treated group. Based on these results, TmIKK-γ might play an important role in antimicrobial innate immune responses in Tenebrio molitor.

In recent years, pavement distresses have been caused by diverse factors such as spalling, deterioration of repaired sections, blow-up, and alkali aggregate reaction due to changing climate environment of a concrete pavement and its construction and maintenance conditions (supply of materials, increase in use of de-icers, etc,). As a leading repair method for deteriorated concrete pavements, partial-depth repair is implemented in accordance with guidelines of material properties for joints of a concrete pavement and field application evaluation systems, but still some of the repaired sections become deteriorated again at an early stage due to poor construction quality and failure of response to environmental impacts. Distresses that can be corrected with partial-depth repairs are largely divided into those of repair materials and of the existing pavement bonded to repair materials, and combined distress of repair materials and the existing pavement. Although re-repair methods should be different by distress type and scale than conventional pavement repair methods, appropriate repair methods and guidance for re-repairs have not been in place so far, and therefore currently, re-repair practices follow the existing manual of partial depth repairs. Therefore, this study evaluated concrete bond characteristics by removing method and repair scope for an experimental section of frequently distressed pavements to determine a re-repair scope and method for deteriorated partial depth repair sections of concrete pavement, the number of which has increased over time.

2017년 추계에 남해 전선역을 파악하고, 알칼리 인산분해 효소(Alkaline Phosphatase; APase) 활성을 이용하여 제한 영양염과 제한 영양염의 시간적인 변화를 평가하였다. 전선역이 형성된 인근해역의 경우, 용존무기인(dissolved inorganic phosphorus; DIP)의 농도와 용존무 기질소(dissolved inorganic nitrogen; DIN): DIP 비가 각각 0.2 μM 이하와 최대 23.2로, DIP가 제한된 환경임에도 불구하고 Chlorophyll a(Chl.-a)가 0.2 μg/L로 높은 생물생산력을 보였다. APase와 DIP는 중요한 역의 상관관계(r = -0.81; P<0.001)를 보여, DIP가 제한되어진 해역임을 알 수 있 었으며, APase와 Chl-a 관계는 APase의 60%가 식물플랑크톤, 40%가 박테리아 기원인 것으로 평가되었다. 용존태 APase와 입자태 APase의 분포로부터 전선역은 장기간 DIP가 제한된 해역이며, 그 외의 해역은 최근에 DIP 제한이 해소된 것으로 판단되었다. 따라서 전선역에서 APase와 같이 가수분해효소의 측정은 제한 영양염의 시공간적인 변화 특성을 평가할 수 있으며, 전선역에서 생지화학 순환의 이해를 높일 수 있을 것으로 생각된다.

본 연구는 참굴(Crassostrea gigas)의 패각운동을 이용하여, 연안역에서 발생하는 저염수에 대한 조기경보가능성을 살펴보았다. 30 psu와 20 psu에서 패각운동은 각각 7.32±3.21회/hr와 7.11±3.90회/hr였으며, 파형과 횟수는 차이가 없었다(t-test, p>0.001). 하지만 10 psu와 5 psu 에서는 모든 개체가 폐각상태를 지속하였다. 수온과 염분의 복합실험결과, Group 1(수온 15 ×염분 15 psu)은 20 30 psu에서 보인 패각운 동 후(약 2 3시간), 장시간 폐각을 하였다. Group 2(수온 30 ×염분 15 psu)에서는 Group 1의 패각 개폐운동보다 더 빠르고 자주 나타나, 참 굴의 생리적인 위기상황에 대한 신호를 나타내었다. 따라서 이러한 파형은 하계 저염수 출현 시 나타낼 수 있는 조기경보 신호로 충분히 활용될 수 있을 것으로 보인다.

이상 고수온을 감지하기 위한 생물모니터링 시스템(BMS) 연구를 위해, 4단계의 수온(5, 10, 20와 30℃)에서 참굴 패각운동을 측정하였다. 모든 참굴은 실험시작 전에 3일 동안 절식을 통하여, 먹이섭이 및 배출에 따른 패각운동의 요인을 제거하였다. 5℃ 실험구에서는 패각운동이 관찰되지 않았지만, 수온의 증가와 함께 패각운동은 증가하였다(10℃ : 6.31±2.18 times/hr, 20℃ : 22.0±10.0 times/hr). 30℃에서는 5℃와 같이 패각운동이 전혀 보이지 않았던 실험구와 20℃와 유사한 패각운동이 실험구가 나타났다. 이는 30℃ 이상에서도 20℃와 같은 신진대사를 보이는 개체군이 있었으나, 대부분이 신진대사의 활력의 감소에 기인하여 폐각상태가 지속되는 것으로 나타났다. 따라서 참굴 양식장에 고수온 감지를 위한 참굴 패각운동 BMS를 설치한다면, 경계단계는 빠른 패각운동(약 30.0회/hr 이상)일 때, 심각단계는 수시간 이상 폐각상태일 때, 조기경보(early warning)를 내릴 수 있을 것이다. 따라서 참굴 패각운동을 활용한 BMS는 이상고수온의 조기경보에 대하여 효과적으로 활용이 가능할 것으로 판단된다.

Earthworms, especially Eisenia andrei, are cultivated for a variety of purposes including waste disposal and compost production. In this study, bacteria from earthworm gut were cultured and the dominant species identified. Subsequently, we isolated bacteriophages able to lyse the isolated gut bacteria. Two dominant genera of gut bacteria, Aeromonas sp. and Citrobacter sp. were identified by using MALDI-TOF MS analysis and a library was constructed to find lytic phages. Phage EF1 showed lytic activity for C. freundii and two Citrobacter isolates, C. braakii and C. murliniae. These 3 species have similar sensitivities to EF1. Several aspects of the life cycle of EF1 were investigated by using C. freundii under optimal growth conditions. EF1 infects C. freundii with a moderate latent period, approximately 25 min, and a large burst size averaging 5 × 109 per infected cell. Moreover, the antimicrobial activity of EF1 was well maintained under diverse conditions including a broad temperature range of 40°C to 50°C and a wide pH range of 4 to 11. In conclusion, the results indicate that earthworm casting contain a wide range of bacteria species, for which there are various corresponding bacteriophages.

Most previous studies on dinoflagellates in Korean coastal areas were conducted without morphological descriptions and illustrations of the observed dinoflagellates. This indicates that the species and diversity of dinoflagellates may have been respectively misidentified and underestimated in the past, probably due to cell shrinkage, distortion and loss caused by sample fixation. This study provides information on the morphological observations of four dinoflagellate orders (Prorocentrales, Dinophysiales, Gonyaulacales and Gymnodiniales) from Jangmok Harbour in Jinhae Bay, Korea. The unfixed samples were collected weekly from December 2013 to February 2015. A total of 13 genera and 30 species were identified using light and scanning electron microscopy, although some samples were not clarified at the species level. Harmful dinoflagellates, Prorocentrum donghaiense, Tripos furca, Alexandrium affine, A. fundyense, Akashiwo sanguinea and Cochlodinium polykrikoides, were identified based on the morphological observations. The results also reflect the occurrence and identification of dinoflagellates that had not been previously recorded in Jangmok Harbour.

본 연구는 소형화된 홀 소자를 이용하여 국내 패류 양식 생물 중 가장 많은 생산량을 보이는 참 굴(Crassostrea gigas)의 패각운동을 기초로, 연안역에서 빈산소에 대한 생물모니터링 시스템의 적 용 가능성을 조사하였다. 정상상태 패각운동의 측정을 위해서 여과해수에서 측정한 결과, 참굴 개 체는 평균 5~12 mm 정도의 개각상태를 유지하였으며, 패각운동 시 비교적 빠른 폐각상태를 보 였다가 느린 속도의 개각상태의 운동이 관찰되었다. 하지만, 주 · 야간 사이에는 큰 차이가 없었다 (p <0.05). 용존산소 농도를 7 mg l-1에서 3 mg l-1까지 감소시키면, 패각운동의 횟수는 증가를 나 타내었으며, 파형도 정상상태와 다르게 불안정한 파형을 보였다. 또한 용존산소가 2 mg l-1로 감 소된 후에는 패각운동의 크기가 점차 작아지거나, 폐각상태를 지시하는 파형이 관찰되었다. 이와 같은 생물모니터링 시스템을 패류 양식에 활용하여 빈산소와 같은 해양환경의 이상변동을 신속히 감지할 수 있다면, 어업피해를 감소시킬 수 있을 것으로 기대된다.

동해 남서해역과 같이 용존 무기 질소(dissolved inorganic nitrogen; DIN)가 제한된 환경에서 우점 규조류 Chaetoceros debilis와 Leptocylindrus danicus의 용존 유기 질소(dissolved organic nitrogen; DON)의 이용성을 정량적으로 평가하였다. 질소원으로 DIN은 질산염과 암모늄, DON은 동해에서 중요한 비율을 차지하는 글리신(glycine)과 요소(urea)에 관하여 각각 평가하였다. Monod 식으로부터 유도한 C. debilis의 최대생장속도(μmax)와 반포화상수(Ks)는 질산염에서 1.50 day-1와 1.62 μM, 암모늄에서 1.13 day-1와 6.97 μM, 글리신 1.46 day-1와 3.36 μM, 요소 0.93 day-1와 0.55 μM으로 나타났다. 또한 L. danicus는 질산염에서 1.55 day-1와 5.21 μM, 암모늄에서 1.57 day-1와 4.57 μM, 글리신 1.47 day-1와 3.80 μM, 요소 1.42 day-1와 1.94 μM이었다. 두 종 모두 요소에서 용존 무기 질소보다 상대적으로 높은 친화성이 확인되었으며, 이러한 높은 친화성은 DIN 제한된 상태에서 C. debilis와 L. danicus이 생장을 유지하기 위해 요소를 이용할 것으로 판단되어진다. 따라서 동해 남서해역과 같이 DIN이 제한된 해역의 경우, DON의 효율적인 이용이 식물플랑크톤의 우점화 전략에서 중요한 요인 중 하나로 생각된다.