Samaniego-Barrón Luisa, Luna-Castro Sarahí, Piña-Vázquez Carolina, Suárez-Güemes Francisco, de la Garza Mireya
Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV-IPN), Avenida Instituto Politécnico Nacional No. 2508, Colonia San Pedro Zacatenco, CP 07360, Ciudad de México, Mexico.
Facultad de Medicina Veterinaria y Zootecnia Dr. Norberto Treviño Zapata, Universidad Autónoma de Tamaulipas, Carretera a Cd. Mante Km 5, CP 87000, Ciudad Victoria, Tamaulipas, Mexico.
Vet Res. 2016 Sep 6;47(1):93. doi: 10.1186/s13567-016-0378-1.
Mannheimia haemolytica is a Gram negative bacterium that is part of the bovine respiratory disease, which causes important economic losses in the livestock industry. In the present work, the interaction between M. haemolytica A1 and bovine lactoferrin (BLf) was studied. This iron-chelating glycoprotein is part of the mammalian innate-immune system and is present in milk and mucosal secretions; Lf is also contained in neutrophils secondary granules, which release this glycoprotein at infection sites. It was evidenced that M. haemolytica was not able to use iron-charged BLf (BholoLf) as a sole iron source; nevertheless, iron-lacked BLf (BapoLf) showed a bactericidal effect against M. haemolytica with MIC of 4.88 ± 1.88 and 7.31 ± 1.62 μM for M. haemolytica strain F (field isolate) and M. haemolytica strain R (reference strain), respectively. Through overlay assays and 2-D electrophoresis, two OMP of 32.9 and 34.2 kDa with estimated IP of 8.18 and 9.35, respectively, were observed to bind both BapoLf and BholoLf; these OMP were identified by Maldi-Tof as OmpA (heat-modifiable OMP) and a membrane protein (porin). These M. haemolytica BLf binding proteins could be interacting in vivo with both forms of BLf depending on the iron state of the bovine.
溶血曼氏杆菌是一种革兰氏阴性细菌，是牛呼吸道疾病的病原体之一，给畜牧业造成了重大经济损失。在本研究中，对溶血曼氏杆菌A1与牛乳铁蛋白（BLf）之间的相互作用进行了研究。这种铁螯合糖蛋白是哺乳动物先天免疫系统的一部分，存在于牛奶和粘膜分泌物中；乳铁蛋白（Lf）也存在于中性粒细胞的次级颗粒中，在感染部位释放这种糖蛋白。结果表明，溶血曼氏杆菌不能将带铁的BLf（BholoLf）作为唯一的铁源；然而，缺铁的BLf（BapoLf）对溶血曼氏杆菌具有杀菌作用，对溶血曼氏杆菌F株（田间分离株）和溶血曼氏杆菌R株（参考菌株）的最低抑菌浓度分别为4.88±1.88和7.31±1.62μM。通过覆盖分析和二维电泳，观察到两种分子量分别为32.9和34.2 kDa、估计等电点分别为8.18和9.35的外膜蛋白（OMP）能与BapoLf和BholoLf结合；这些OMP经基质辅助激光解吸电离飞行时间质谱（Maldi-Tof）鉴定为OmpA（热可修饰OMP）和一种膜蛋白（孔蛋白）。溶血曼氏杆菌的这些BLf结合蛋白可能在体内根据牛的铁状态与两种形式的BLf相互作用。
