Elsner H A, Hönck H H, Willmann F, Kreienkamp H J, Iglauer F
Department of Transfusion Medicine, Hannover Medical School, Germany.
Comp Med. 2000 Apr;50(2):206-11.
Episodic phases of continuous poor-quality oocytes obtained from South American Clawed Frogs (Xenopus laevis) often are observed. In publications dealing with the surgical technique of oocyte removal, the frogs' robust constitution and resistance against infections provided by magainins are pointed out. For this reason, clean rather than sterile conditions for the surgical procedure are mostly recommended. However, in most instances, antibiotics are added to the buffer medium when in vitro experiments are performed using oocytes.
After a long phase of poor oocyte quality at our facility, involving oocytes that had been obtained by use of a "clean" surgical procedure, we subsequently cultured oocytes in a buffer medium containing the three antibiotics: penicillin G, gentamicin, and streptomycin.
During DNA injection experiments, the oocytes developed black spots on their surface by postoperative day two. Pure culture of the gram-negative non-fermentative rod Pseudomonas fluorescens was obtained from the impaired oocytes; the isolate was resistant to the three antibiotics. By contrast, after aseptic surgical removal and culture of oocytes in buffer medium containing the antibiotics tetracycline and gentamicin, perfect oocytes without bacterial contamination were obtained.
Whenever impaired oocyte quality is observed, microbial contamination should be considered as a possible cause.
经常观察到从南美爪蟾（非洲爪蟾）获取的卵母细胞持续出现质量不佳的阶段性情况。在有关卵母细胞摘除手术技术的出版物中，指出了爪蟾强健的体质以及蛙皮抗菌肽所提供的抗感染能力。因此，大多建议手术过程采用清洁而非无菌的条件。然而，在大多数情况下，当使用卵母细胞进行体外实验时，会在缓冲培养基中添加抗生素。
在我们的实验机构经历了一段卵母细胞质量不佳的漫长阶段后，涉及通过“清洁”手术程序获取的卵母细胞，我们随后在含有青霉素G、庆大霉素和链霉素这三种抗生素的缓冲培养基中培养卵母细胞。
在DNA注射实验期间，卵母细胞在术后第二天其表面出现黑点。从受损的卵母细胞中获得了革兰氏阴性非发酵菌荧光假单胞菌的纯培养物；该分离株对这三种抗生素具有抗性。相比之下，在无菌手术摘除卵母细胞并在含有四环素和庆大霉素的缓冲培养基中培养后，获得了无细菌污染的完美卵母细胞。
每当观察到卵母细胞质量受损时，应将微生物污染视为可能的原因。
