• 한국동물학회지
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• 제38권1호
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• pp.125-135
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• 1995

붉은지렁이 (Lumbricus rubellus)의 체내에 존재하는 prophenoloxidase-phenoloxidase(prPO$\longrightarrow$PO)의 활성계는 몇 종류의 다른 경로에 의해 활성화 됨을 발견하였다 Propo는 exogenous trypsin $\beta$ 1.3-glucan, Ca2' 이온. lipopolysaccharide (LPS) 및 열처리 등에 의하여 활성도가 증가 되었고 Ca2' 이온이 나머지 4가지 종류의 처리와 함께 병행되었을 때 그 효과가 더욱 증가하였다 Propo의 활성도는 LPS나 Ca2' 이온의 농도가 각각 1 5H 10-s g Lps/r리, 15 mM(Ca2')의 농도에서 propo의 최대활성치를 나타냈으나 그 이상의 농도에서는 propo의 활성이 오히려 감소하였다. LPS. $\beta$ 1,3-glucan 및 Ca2' 이온 등은 trypsin 억제인자인 soybean trypsin inhibitor(571)가 함께 존재할 경우 전혀 propo를 활성화 시킨지 못하는 것으로 미루어 $\beta$ 1,3-glucan 및 Ca2' 이온 등은 체내의 trypsin 유사 효소의 활성을 증가시켜 궁극적으로는 proPO$\longrightarrow$PO의 활성화 반응에 간접적으로 작용한다고 생각되었다. 한편. 571의 존재하에서도 50"C의 열처리는 propo의 활성화에 아주 효과적인 물리적 요인으로 작용하였다. 따라서 열처리는 Ca2'이나 LPS. f 1,3-glucan파는 달리 직접적으로 proPO$\longrightarrow$PO의 활성화 반응에 작용하는 것으로 생각되어 붉은 지렁이의 체내에서 proPO가 활성화되는 괴정(propo-activating system)에는 최소한 2가지 이상의 경로가 있다고 생각된다.생각된다.

• BMB Reports
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• 제46권5호
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• pp.264-269
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• 2013

Pattern recognition receptors are known to participate in the activation of Prophenoloxidase system. In this study, a 1,3-${\beta}$-D-glucan recognition protein was detected for the first time in Antheraea pernyi larvae (Ap-${\beta}GRP$). Ap-${\beta}GRP$ was purified to 99.9% homogeneity from the hemolymph using traditional chromatographic methods. Ap-${\beta}GRP$ specifically bind 1,3-${\beta}$-D-glucan and yeast, but not E. coli or M. luteus. The 1,3-${\beta}$-D-glucan dependent phenoloxidase (PO) activity of the hemolymph inhibited by anti-Ap-${\beta}GRP$ antibody could be recovered by addition of purified Ap-${\beta}GRP$. These results demonstrate that Ap-${\beta}GRP$ acts as a biosensor of 1,3-${\beta}$-Dglucan to trigger the Prophenoloxidase system. A trace mount of 1,3-${\beta}$-D-glucan or Ap-${\beta}GRP$ alone was unable to trigger the proPO system, but they both did. Ap-${\beta}GRP$ was specifically degraded following the activation of proPO with 1,3-${\beta}$-Dglucan. These results indicate the variation in the amount of Ap-${\beta}GRP$ after specific immune challenge in A. pernyi hemolymph is an important regulation mechanism to immune response.

• Molecules and Cells
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• 제26권6호
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• pp.606-610
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• 2008

Phenoloxidase (PO), a melanin-forming enzyme around the foreign bodies, is an important component of the host defense system in invertebrates. Pro-PO is the enzymatically inactive zymogen form of PO. In the Drosophila genome, three Pro-PO isoforms have been identified to date. These include Pro-PO1 and 2, which are primarily expressed in crystal cells, and Pro-PO3, which is predominantly found in the lamellocytes. In this study, we demonstrated that Drosophila Pro-PO3, but not Pro-PO1 or 2, is enzymatically active in its zymogen form. These findings were evidenced by spectacular melanin forming capacities of various cells and tissues that overexpressed these pro-enzymes. Furthermore, the melanization phenotype observed in the lamellocyte-enriched $hop^{Tum-l}$ mutant was drastically reduced in the absence of PPO3, indicating that PPO3 plays a major role in the lamellocyte-mediated spontaneous melanization process. Taken together, these findings indicate that the biochemical properties, activation mode and in vivo role of Pro-PO3 are likely distinct from those of the other two Pro-PO enzymes involved in Drosophila physiology.

• BMB Reports
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• 제34권1호
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• pp.15-20
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• 2001

One of the innate immune reactions in invertebrates is the pro-phenoloxidase (pro-PO) activation system that is involved in the generation of superoxide, melanin synthesis, and the subsequent sequestration of foreign matter entering the hemocoel of the invertebrates. However, the molecular mechanism of this biological reaction is still obscure. To expand our understanding of the biological roles of the pro-PO activation system in invertebrates, we performed a yeast two-hybrid screening by using three regions of pro-PO as bait and a yeast two-hybrid cDNA library from Tenebrio molitor larvae as prey We isolated a novel partial cDNA clone that encodes a glycine-rich protein that interacted with the active phenoloxidase (termed phenoloxidase interacting protein, POIP). POIP consists of two domains: One is an N-terminal unique domain and the other is a C-terminal glycine-rich domain. The C-terminal glycine-rich domain showed sequential homology with those of insect antifungal proteins. Also, the yeast two-hybrid screen in a reverse orientation (using POIP as bait) yielded PO, suggesting that the PO-POIP interaction is specific. By using a 315 bP PCR fragment of the N-terminal unique region of POIP, we cloned the full-length cDNA of POIP from the Tenebruo cDNA library constructed by using E. coli injected larvae. The interaction analysis between PO, and a truncated fragment lacking the N-terminal unique region of POIP, indicated that the N-terminal unique region is necessary for interaction between PO and POIP. The expression level of the POIP mRNA is increased by bacterial injection into T. molitor larvae. This suggests that POIP might be engaged in the humoral defense reaction.