珊瑚疾病与摄食:以海葵()模型系统探究异养在病原菌 spp. 传播中的作用。
Coral Disease and Ingestion: Investigating the Role of Heterotrophy in the Transmission of Pathogenic spp. using a Sea Anemone () Model System.
机构信息
Department of Environmental Health Science, University of Georgia, Athens, Georgia, USA.
出版信息
Appl Environ Microbiol. 2023 Jun 28;89(6):e0018723. doi: 10.1128/aem.00187-23. Epub 2023 May 16.
Understanding disease transmission in corals can be complicated given the intricacy of the holobiont and difficulties associated with coral cultivation. As a result, most of the established transmission pathways for coral disease are associated with perturbance (i.e., damage) rather than evasion of immune defenses. Here, we investigate ingestion as a potential pathway for the transmission of coral pathogens that evades the mucus membrane. Using sea anemones () and brine shrimp ( sp.) to model coral feeding, we tracked the acquisition of the putative pathogens, Vibrio alginolyticus, V. harveyi, and using GFP-tagged strains. sp. were provided to anemones using 3 experimental exposures (i) direct water exposure alone, (ii) water exposure in the presence of a food source (non-spiked ), and (iii) through a "spiked" food source (-colonized ) created by exposing cultures to GFP- via the ambient water overnight. Following a 3 h feeding/exposure duration, the level of acquired GFP was quantified from anemone tissue homogenate. Ingestion of spiked resulted in a significantly greater burden of GFP- equating to an 830-fold, 3,108-fold, and 435-fold increase in CFU mL when compared to water exposed trials and a 207-fold, 62-fold, and 27-fold increase in CFU mL compared to water exposed with food trials for V. alginolyticus, V. harveyi, and , respectively. These data suggest that ingestion can facilitate delivery of an elevated dose of pathogenic bacteria in cnidarians and may describe an important portal of entry for pathogens in the absence of perturbing conditions. The front line of pathogen defense in corals is the mucus membrane. This membrane coats the surface body wall creating a semi-impermeable layer that inhibits pathogen entry from the ambient water both physically and biologically through mutualistic antagonism from resident mucus microbes. To date, much of the coral disease transmission research has been focused on mechanisms associated with perturbance of this membrane such as direct contact, vector lesions (predation/biting), and waterborne exposure through preexisting lesions. The present research describes a potential transmission pathway that evades the defenses provided by this membrane allowing unencumbered entry of bacteria as in association with food. This pathway may explain an important portal of entry for emergence of idiopathic infections in otherwise healthy corals and can be used to improve management practices for coral conservation.
了解珊瑚中的疾病传播可能很复杂,因为生物整体和珊瑚养殖相关的困难。因此,大多数已建立的珊瑚疾病传播途径都与干扰(即损伤)有关,而不是逃避免疫防御。在这里,我们研究了作为逃避粘液膜免疫防御的珊瑚病原体传播的潜在途径的摄入。使用海葵()和丰年虾()来模拟珊瑚的摄食,我们跟踪了假定病原体的获得,包括 弧菌、哈维氏弧菌和 使用 GFP 标记的菌株。将丰年虾提供给海葵,进行了 3 种实验暴露(i)单独的直接水暴露,(ii)在有食物源(未添加)的情况下的水暴露,以及(iii)通过隔夜通过环境水将 GFP-暴露于 培养物,从而创建“添加”食物源(-定植)。在 3 小时的摄食/暴露时间后,从海葵组织匀浆中定量获得的 GFP 水平。与水暴露试验相比,摄入添加的丰年虾导致 GFP- 的负担显著增加,相当于 弧菌、哈维氏弧菌和 的 CFU mL 分别增加了 830 倍、3108 倍和 435 倍,与水暴露与食物试验相比,CFU mL 分别增加了 207 倍、62 倍和 27 倍。这些数据表明,在刺胞动物中,摄入可以促进高剂量致病性细菌的传递,并且在没有干扰条件的情况下,可能描述了病原体进入的重要门户。在珊瑚中,病原体防御的第一道防线是粘液膜。该膜覆盖在体表壁上,形成半渗透层,通过共生粘液微生物的相互拮抗,在物理和生物上抑制病原体从环境水中进入。迄今为止,大多数珊瑚疾病传播研究都集中在与该膜的干扰相关的机制上,例如直接接触、载体损伤(捕食/咬伤)以及通过预先存在的损伤通过水传播。本研究描述了一种潜在的传播途径,该途径可以逃避该膜提供的防御,使细菌不受阻碍地进入,就像与食物有关一样。这种途径可以解释健康珊瑚中特发性感染的重要门户,并可用于改善珊瑚保护的管理实践。