Marine Apex Predator Research Unit (MAPRU), Institute for Coastal and Marine Research, Nelson Mandela University, Port Elizabeth, South Africa.
DST/NRF Centre of Excellence at the Percy FitzPatrick Institute for African Ornithology, Department of Zoology, Nelson Mandela University, Port Elizabeth, South Africa.
Parasit Vectors. 2018 Sep 24;11(1):525. doi: 10.1186/s13071-018-3089-9.
Anaplasma spp. are Gram-negative obligate intracellular bacteria transmitted by ticks. Even though numerous studies have detected DNA from Anaplasma spp. in the blood of birds, thus far mammals were the only vertebrates demonstrated to serve as competent hosts to these organisms. We report a novel candidate species of Anasplasma that was associated with cytoplasmic inclusions in the erythrocytes of an African penguin (Spheniscus demersus) in South Africa.
Cytoplasmic inclusions were morphologically characterized from freshly-produced blood smears, and phylogenetic analysis of 16S rRNA and groEL genes were used to evaluate the evolutionary relationships of the organism to other Anaplasmataceae.
Dark-purple round or oval inclusions consistent with Anaplasmataceae morulae were observed in the cytoplasm of erythrocytes. Phylogenetic trees produced using different methods agreed that the organism detected in this study belongs to the genus Anaplasma, and suggested that it is most closely related to the cluster comprising A. centrale, A. capra, A. marginale and A. ovis. We propose provisionally naming the strain detected in this study as "Candidatus Anaplasma sphenisci".
This is the first species of Anaplasma shown to produce cytoplasmic inclusions in avian cells, opening the possibility that cytoplasmic inclusions in avian erythrocytes that had previously been attributed to Aegyptianella sp. might in fact correspond to Anaplasma. Further studies on the molecular biology of avian-infecting Anaplasmataceae will be valuable to provide insight into the evolution and epidemiology of these organisms.
无形体属是革兰氏阴性专性细胞内细菌，通过蜱传播。尽管许多研究已经在鸟类血液中检测到无形体属的 DNA，但到目前为止，哺乳动物是唯一被证明能成为这些生物有效宿主的脊椎动物。我们报告了一种新型的无形体候选物种，它与南非非洲企鹅（Spheniscus demersus）的红细胞中的细胞质包涵体有关。
从新鲜制备的血涂片上对细胞质包涵体进行形态学特征描述，并对 16S rRNA 和 groEL 基因进行系统发育分析，以评估该生物与其他无形体科之间的进化关系。
在红细胞细胞质中观察到与无形体科包涵体一致的深紫色圆形或椭圆形包涵体。使用不同方法生成的系统发育树一致表明，本研究中检测到的生物属于无形体属，并且提示它与包含 A. centrale、A. capra、A. marginale 和 A. ovis 的聚类最为密切相关。我们建议将本研究中检测到的菌株暂时命名为“Candidatus Anaplasma sphenisci”。
这是第一个在禽类细胞中产生细胞质包涵体的无形体种，这为以前归因于埃及体属的禽类红细胞中的细胞质包涵体实际上可能对应于无形体的可能性开辟了道路。进一步研究禽类感染无形体科的分子生物学将有助于深入了解这些生物的进化和流行病学。
