Vazquez-Cruz Candelario, Reyes-Malpica Edmundo, Montes-García J Fernando, Bautista-Betancourt Pamela, Cobos-Justo Elena, Avalos-Rangel Miguel A, Negrete-Abascal Erasmo
Centro de Investigaciones en Ciencias Microbiológicas, BUAP, Apdo. Postal1622,, Puebla, México.
Carrera de Biología, Facultad de Estudios Superiores Iztacala, UNAM, Av. de los Barrios # 1, Los Reyes Iztacala, 54090, Tlalnepantla, Estado de México, Mexico.
Folia Microbiol (Praha). 2025 May 10. doi: 10.1007/s12223-025-01271-7.
Ovine epididymitis, caused by Actinobacilus seminis, is an infectious disease that produces atrophy of the testis, low fertility, and sterility in infected animals. Iron is a microelement necessary for different vital functions in all organisms and most microorganisms. A. seminis iron acquisition mechanisms are undiscovered. For this reason, this work aimed to know the mechanisms this bacterium possesses to respond when grown in an iron restriction culture medium. A. seminis up-expressed three proteins, including a transferrin binding protein, and down-expressed seven (enzymes and putative adhesins) proteins when grown with 2,2'dipyridyl. With chelate, its growth was reduced by 40%, but it was recovered by adding 50-µM FeCl. No siderophore production was detected with the CAS-BHI medium assay, but siderophore transporter proteins are present. Under normal growth conditions, this microorganism expresses a protein of 70 kDa, identified by mass spectrometry as DnaK. A. seminis DnaK interacts with biotin-labeled transferrin, lactoferrin, or bovine hemoglobin but not with biotin-labeled apo-transferrin or apo-lactoferrin, suggesting its participation in iron acquisition. This protein diminished its expression in iron restriction conditions at 37 °C but remained unchanged at 40 °C, and it is immune recognized by sheep serum with epididymitis. These different iron acquisition mechanisms could give rise to A. seminis, infecting different host tissues.
由精液放线杆菌引起的绵羊附睾炎是一种传染病，可导致受感染动物的睾丸萎缩、生育力低下和不育。铁是所有生物体和大多数微生物中不同重要功能所必需的微量元素。精液放线杆菌的铁获取机制尚未被发现。因此，这项工作旨在了解这种细菌在铁限制培养基中生长时所具有的反应机制。当在2,2'-联吡啶存在下生长时，精液放线杆菌上调表达了三种蛋白质，包括一种转铁蛋白结合蛋白，下调表达了七种（酶和假定的粘附素）蛋白质。使用螯合剂时，其生长降低了40%，但通过添加50μM的FeCl3得以恢复。用CAS-BHI培养基检测未检测到铁载体的产生，但存在铁载体转运蛋白。在正常生长条件下，这种微生物表达一种70 kDa的蛋白质，通过质谱鉴定为DnaK。精液放线杆菌的DnaK与生物素标记的转铁蛋白、乳铁蛋白或牛血红蛋白相互作用，但不与生物素标记的脱铁转铁蛋白或脱铁乳铁蛋白相互作用，表明其参与铁的获取。这种蛋白质在37°C的铁限制条件下表达减少，但在40°C时保持不变，并且它能被患有附睾炎的绵羊血清免疫识别。这些不同的铁获取机制可能导致精液放线杆菌感染不同的宿主组织。
