Lúquez Carolina, Raphael Brian H, Maslanka Susan E
Enteric Diseases Laboratory Branch, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
Appl Environ Microbiol. 2009 Oct;75(19):6094-101. doi: 10.1128/AEM.01009-09. Epub 2009 Aug 14.
There is limited knowledge of the neurotoxin gene diversity among Clostridium botulinum type Ab strains. Only the sequences of the bont/A and bont/B genes in C. botulinum type Ab strain CDC1436 and the sequence of the bont/B gene in C. botulinum type Ab strain CDC588 have been reported. In this study, we sequenced the entire bont/A- and bont/B-associated neurotoxin gene clusters of C. botulinum type Ab strain CDC41370 and the bont/A gene of strain CDC588. In addition, we analyzed the organization of the neurotoxin gene clusters in strains CDC588 and CDC1436. The bont/A nucleotide sequence of strain CDC41370 differed from those of the known bont/A subtypes A1 to A4 by 2 to 7%, and the predicted amino acid sequence differed by 4% to 14%. The bont/B nucleotide sequence in strain CDC41370 showed 99.7% identity to the sequence of subtype B1. The bont/A nucleotide sequence of strain CDC588 was 99.9% identical to that of subtype A1. Although all of the C. botulinum type Ab strains analyzed contained the two sets of neurotoxin clusters, similar to what has been found in other bivalent strains, the intergenic spacing of p21-orfX1 and orfX2-orfX3 varied among these strains. The type Ab strains examined in this study had differences in their toxin gene cluster compositions and bont/A and bont/B nucleotide sequences, suggesting that they may have arisen from separate recombination events.
关于A型和B型肉毒梭菌菌株中神经毒素基因多样性的了解有限。仅报道了A型和B型肉毒梭菌菌株CDC1436中的肉毒杆菌神经毒素A（bont/A）和肉毒杆菌神经毒素B（bont/B）基因序列，以及A型和B型肉毒梭菌菌株CDC588中的bont/B基因序列。在本研究中，我们对A型和B型肉毒梭菌菌株CDC41370的整个bont/A和bont/B相关神经毒素基因簇以及菌株CDC588的bont/A基因进行了测序。此外，我们分析了菌株CDC588和CDC1436中神经毒素基因簇的组织情况。菌株CDC41370的bont/A核苷酸序列与已知的A1至A4型bont/A亚型的序列相差2%至7%，预测的氨基酸序列相差4%至14%。菌株CDC41370中的bont/B核苷酸序列与B1亚型的序列具有99.7%的同一性。菌株CDC588的bont/A核苷酸序列与A1亚型的序列具有99.9%的同一性。尽管所有分析的A型和B型肉毒梭菌菌株都含有两组神经毒素簇，这与在其他二价菌株中发现的情况类似，但这些菌株中p21-orfX1和orfX2-orfX3的基因间隔有所不同。本研究中检测的A型和B型菌株在毒素基因簇组成以及bont/A和bont/B核苷酸序列方面存在差异，这表明它们可能来自不同的重组事件。
