Groman N, Cianciotto N, Bjorn M, Rabin M
Infect Immun. 1983 Oct;42(1):48-56. doi: 10.1128/iai.42.1.48-56.1983.
Three probes have been described which can be used to detect the presence of DNA sequences homologous to the tox gene of Corynebacterium diphtheriae. Probes "A" and "B" detected sequences coding for A and B fragments of diphtheria toxin, respectively. The third "A-B" probe contained both the A and B coding sequences. The B probe was completely unambiguous in detecting only toxin-related sequences, and the A probe was only slightly less so. The efficacy of the probes was tested on a series of toxinogenic and nontoxinogenic isolates of C. diphtheriae. All isolates which were toxinogenic as characterized by the gel immunodiffusion technique gave positive reactions with the probes. Of particular interest was the finding that 14 of 43 nontoxinogenic isolates also carried DNA homologous to both the A and B probes. All 14 isolates were nontoxinogenic by the rabbit intracutaneous test as well as by the gel immunodiffusion test; however, 12 of them produced ADP-ribosylating activity, whereas two were negative. The isolates producing ADP-ribosylating activity belonged to a cohort of cultures, of which 11 were isolated in South Dakota and 1 was isolated in Montana. Genomic DNAs of all 12 appeared to be identical when restriction enzyme digest patterns were compared, and the same fragment carried the tox gene in all of them. The tox-bearing nontoxinogenic isolates from Alaska and Florida each had unique restriction patterns and did not produce ADP-ribosylating activity. A number of genomic fragments of all the tox-bearing nontoxinogenic isolates hybridized with beta converting phage DNA. The significance of these observations to the natural history of diphtheria was discussed.
已描述了三种可用于检测与白喉棒状杆菌毒基因同源的DNA序列的探针。探针“A”和“B”分别检测编码白喉毒素A和B片段的序列。第三种“A - B”探针包含A和B编码序列。B探针在仅检测毒素相关序列方面完全明确，A探针的明确性稍差一些。在一系列产毒素和不产毒素的白喉棒状杆菌分离株上测试了这些探针的效力。所有经凝胶免疫扩散技术鉴定为产毒素的分离株与探针均呈阳性反应。特别有趣的是，43株不产毒素的分离株中有14株也携带与A和B探针均同源的DNA。所有14株分离株经兔皮内试验和凝胶免疫扩散试验均不产毒素；然而，其中12株具有ADP核糖基化活性，而两株为阴性。产生ADP核糖基化活性的分离株属于一组培养物，其中11株在南达科他州分离得到，1株在蒙大拿州分离得到。当比较限制性内切酶消化图谱时，所有12株的基因组DNA似乎是相同的，并且相同的片段在所有菌株中都携带毒基因。来自阿拉斯加和佛罗里达的携带毒基因的不产毒素分离株各自具有独特的限制性图谱，并且不产生ADP核糖基化活性。所有携带毒基因的不产毒素分离株的一些基因组片段与β转化噬菌体DNA杂交。讨论了这些观察结果对白喉自然史研究的意义。
