The order Saprolegniales (Class Oomycota) is a group of fungus-like eukaryotic microorganisms that have been associated with infections in fish and fish eggs. Infections with microorganisms from this order are clearly evident because they have a cotton wool-like appearance. The aim of this study was to characterize and identify an oomycete that was isolated from the eye of an Orange Blotched Peacock Cichlid Aulonacara sp. A sample of cotton wool-like mycelia was isolated and single-spore isolations were conducted. Molecular characterization and phylogenetic analysis of the ITS1-5.8-ITS2 rDNA region for all isolates were used for species identification. Following molecular identification, one isolate was used to culture and characterize the reproductive structures. Physiological characterization entailed incubating the isolate on potato dextrose agar (PDA) at five different temperatures, ranging from 5°C to 25°C, to monitor growth rates. A multiple sequence alignment showed 100% similarity between all of the single-spore isolates and alignment with other Achlya bisexualis strains. Long, coarse hyphae with zoosporangia and gemmae typical of the order Saprolegniales were observed with an optimal growth rate at 25°C. The oomycete that was isolated from an Orange Blotched Peacock Cichlid was identified as A. bisexualis, the first record of this species in South Africa.

中文翻译：

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南非观赏鱼中分离出的水霉双性体（Saprolegniaceae）首次记录

水霉目（卵菌纲）是一组真菌样真核微生物，与鱼和鱼卵的感染有关。来自该目微生物的感染非常明显，因为它们具有棉絮状外观。本研究的目的是表征和鉴定从橙斑孔雀 Cichlid Aulonacara sp. 的眼睛中分离出来的卵菌。分离棉绒样菌丝体样品并进行单孢子分离。所有分离株的 ITS1-5.8-ITS2 rDNA 区域的分子特征和系统发育分析用于物种鉴定。在分子鉴定之后，使用一种分离物来培养和表征生殖结构。生理特征需要在 5°C 至 25°C 的五种不同温度下在马铃薯葡萄糖琼脂 (PDA) 上培养分离物，以监测生长速度。多序列比对显示所有单孢子分离株之间的相似性为 100%，并且与其他双性螟菌株的比对具有 100% 的相似性。观察到带有游动孢子囊的长而粗的菌丝和水霉目典型的芽孢，其最佳生长速度为 25°C。从橙色斑点孔雀慈鲷中分离出的卵菌被鉴定为 A. bisexualis，这是该物种在南非的第一个记录。观察到带有游动孢子囊的粗菌丝和水霉目典型的芽孢，其最佳生长速度为 25°C。从橙色斑点孔雀慈鲷中分离出的卵菌被鉴定为 A. bisexualis，这是该物种在南非的第一个记录。观察到带有游动孢子囊的粗菌丝和水霉目典型的芽孢，其最佳生长速度为 25°C。从橙色斑点孔雀慈鲷中分离出的卵菌被鉴定为 A. bisexualis，这是该物种在南非的第一个记录。