School of Marine Sciences, Ningbo University, Ningbo, 315020, China.
School of Marine Sciences, Ningbo University, Ningbo, 315020, China; Laboratory for Marine Biology and Biotechnology, Pilot Qingdao National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266071, China.
Fish Shellfish Immunol. 2024 Sep;152:109799. doi: 10.1016/j.fsi.2024.109799. Epub 2024 Aug 2.
LRR-only protein (LRRop) is an important class of immune molecules that function as pattern recognition receptor in invertebrates, however, the bacterial inhibitory activity of this proteins remain largely unknown. Herein, a novel LRRop was cloned from Eriocheir sinensis and named as EsLRRop2. The EsLRRop2 consists of six LRR motifs and formed a horseshoe shape three-dimension structure. EsLRRop2 was mainly expressed in intestine and hepatopancreas. The transcripts of EsLRRop2 in the intestine and hepatopancreas were induced by Vibrio parahaemolyticus and Staphylococcus aureus, and displayed similar transcriptional profiles. The expression levels of EsLRRop2 responded more rapidly and highly to V. parahaemolyticus than S. aureus in the intestine and hepatopancreas. Although the basal expression level of EsLRRop2 in hemocytes was relatively low, its transcripts in hemocytes were significantly induced by V. parahaemolyticus and S. aureus. The recombinant proteins of EsLRRop2 (rEsLRRop2) displayed a wide range of binding spectrum against vibrios, including V. parahaemolyticus, V. alginolyticus, and V. harveryi. The rEsLRRop2 showed dose- and time-dependent inhibitory activity against V. parahaemolyticus and S. aureus, and it could agglutinate the two bacteria. Furthermore, the inhibitory activities of rEsLRRop2 against V. parahaemolyticus, V. alginolyticus, V. harveryi and S. aureus was slightly affected by pH and salinity, and the rEsLRRop2 displayed the strongest inhibitory activity against all the three vibrios when the salinity was 20 ‰ and pH was 8.0. Collectively, these results elucidate the bacterial binding and inhibitory activities of EsLRRop2, and provide theoretical foundations for the application of rEsLRRop2 in prevention and control of vibrio diseases in aquaculture.
LRR 仅蛋白（LRRop）是一类重要的免疫分子，作为无脊椎动物的模式识别受体发挥作用，然而，其对细菌的抑制活性在很大程度上仍然未知。本研究从中华绒螯蟹中克隆了一种新型的 LRRop，并将其命名为 EsLRRop2。EsLRRop2 由六个 LRR 基序组成，形成马蹄形的三维结构。EsLRRop2 主要在肠和肝胰腺中表达。EsLRRop2 在肠和肝胰腺中的转录物被副溶血弧菌和金黄色葡萄球菌诱导，并表现出相似的转录谱。EsLRRop2 在肠和肝胰腺中对副溶血弧菌的反应更为迅速和强烈。虽然 EsLRRop2 在血细胞中的基础表达水平相对较低，但它的转录物在血细胞中被副溶血弧菌和金黄色葡萄球菌显著诱导。EsLRRop2（rEsLRRop2）的重组蛋白显示出对弧菌的广泛结合谱，包括副溶血弧菌、溶藻弧菌和哈维氏弧菌。rEsLRRop2 对副溶血弧菌和金黄色葡萄球菌表现出剂量和时间依赖性的抑制活性，并能凝集这两种细菌。此外，rEsLRRop2 对副溶血弧菌、溶藻弧菌、哈维氏弧菌和金黄色葡萄球菌的抑制活性受 pH 值和盐度的影响较小，当盐度为 20‰、pH 值为 8.0 时，rEsLRRop2 对所有三种弧菌的抑制活性最强。总之，这些结果阐明了 EsLRRop2 的细菌结合和抑制活性，为 rEsLRRop2 在水产养殖中预防和控制弧菌病的应用提供了理论基础。
