Chandler F W, Kaplan W, Callaway C S
Arch Pathol Lab Med. 1978 Jul;102(7):353-6.
Evidence that algae are pathogens was provided by the results of electron microscopic studies of tissues from five cattle and sheep suspected of having green algal infections. Chloroplasts were demonstrated in the algae in each case. Prototheca organisms, considered by some to be achloric mutants of green algae, are causative agents of disease in man and animals and may appear morphologically similar to green algae in tissue. However, electron microscopy showed that chloroplasts were absent in these organisms. Light microscopy revealed not only similarities in size, shape, and mode of reproduction, but also a striking difference between the Prototheca organisms and green algae. Unlike Prototheca, the green algae contained abundant cytoplasmic starch granules that were strongly positive by several staining procedures; these granules, which were PAS-negative following diastase digestion, provide a means of differentiating green algae from Prototheca cells in tissue.
对五头疑似感染绿藻的牛和羊的组织进行电子显微镜研究的结果，为藻类是病原体提供了证据。在每一例中，藻类中都发现了叶绿体。原藻被一些人认为是绿藻的无叶绿素突变体，是人和动物疾病的病原体，在组织中其形态可能与绿藻相似。然而，电子显微镜显示这些生物体中没有叶绿体。光学显微镜不仅揭示了它们在大小、形状和繁殖方式上的相似性，也显示了原藻与绿藻之间的显著差异。与原藻不同，绿藻含有丰富的细胞质淀粉颗粒，通过几种染色方法染色后呈强阳性；这些颗粒在淀粉酶消化后对PAS呈阴性，这为在组织中区分绿藻和原藻细胞提供了一种方法。
