Figure 4.

Phylogeny of sub-types of botulinum neurotoxin type B. The toxin protein sequences were aligned with the Muscle module of MEGA7 [72] algorithm, and the phylogenetic tree was generated using the Neighbour-Joining method. Variants of six type B neurotoxin sub-types were identified. Scale bar represents the number of amino acid substitutions per site. A total of 239 amino acid sequences were analysed. White blocks represent absence of information regarding source. Black blocks represent reference neurotoxins [45]. Further details about individual sequences and isolates are given in Table S3, where they appear in the same order as in this Figure. The sources of the isolates are given in Table S1.