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Genomic and physiological variability within Group II (non-proteolytic) Clostridium botulinum.

Stringer SC, Carter AT, Webb MD, Wachnicka E, Crossman LC, Sebaihia M, Peck MW - BMC Genomics (2013)

Bottom Line: These results were compared with characteristics determined from physiological tests.However, these two subsets did not differ strongly in minimum growth temperature or maximum NaCl concentration for growth.No relationship was found between tellurite resistance and toxin type despite all the tested type B and type F strains carrying tehB, while the sequence was absent or diverged in all type E strains.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Food Research (IFR), Norwich Research Park, Colney, Norwich NR4 7UA, UK. sandra.stringer@ifr.ac.uk

ABSTRACT

Background: Clostridium botulinum is a group of four physiologically and phylogenetically distinct bacteria that produce botulinum neurotoxin. While studies have characterised variability between strains of Group I (proteolytic) C. botulinum, the genetic and physiological variability and relationships between strains within Group II (non-proteolytic) C. botulinum are not well understood. In this study the genome of Group II strain C. botulinum Eklund 17B (NRP) was sequenced and used to construct a whole genome DNA microarray. This was used in a comparative genomic indexing study to compare the relatedness of 43 strains of Group II C. botulinum (14 type B, 24 type E and 5 type F). These results were compared with characteristics determined from physiological tests.

Results: Whole genome indexing showed that strains of Group II C. botulinum isolated from a wide variety of environments over more than 75 years clustered together indicating the genetic background of Group II C. botulinum is stable. Further analysis showed that strains forming type B or type F toxin are closely related with only toxin cluster genes targets being unique to either type. Strains producing type E toxin formed a separate subset. Carbohydrate fermentation tests supported the observation that type B and F strains form a separate subset to type E strains. All the type F strains and most of type B strains produced acid from amylopectin, amylose and glycogen whereas type E strains did not. However, these two subsets did not differ strongly in minimum growth temperature or maximum NaCl concentration for growth. No relationship was found between tellurite resistance and toxin type despite all the tested type B and type F strains carrying tehB, while the sequence was absent or diverged in all type E strains.

Conclusions: Although Group II C. botulinum form a tight genetic group, genomic and physiological analysis indicates there are two distinct subsets within this group. All type B strains and type F strains are in one subset and all type E strains in the other.

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Venn diagram showing the relatedness of Group II C. botulinum strains. Orthologous CDSs were calculated between the three available Group II C. botulinum genome sequences by reciprocal FASTA best match analysis. CDSs shared between specific strains and CDSs unique to a particular strain are plotted on the Venn diagram.
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Figure 2: Venn diagram showing the relatedness of Group II C. botulinum strains. Orthologous CDSs were calculated between the three available Group II C. botulinum genome sequences by reciprocal FASTA best match analysis. CDSs shared between specific strains and CDSs unique to a particular strain are plotted on the Venn diagram.

Mentions: Regions that were unique to the Eklund 17B (NRP) genome but were not associated with phage were also detected. Many of these regions carry CDSs for enzymes involved in metabolic pathways, regulators and transporters. Other regions specify cell envelope components. Specific unique CDSs include cold shock and heat shock proteins. A CDS for a predicted protein with similarity to an endolysin from C. beijerinckii, a septicolysin similar to that from C. septicum and a CDS sharing significant similarity with an internalin from Listeria ivanovii is also present. A Venn diagram was formulated to represent the number of CDS shared between the three sequenced Group II C. botulinum strains and the numbers of unique CDS (Figure 2). A total of 2521 CDS were common to all three strains out of a total of between 3257 and 3684 CDS (Figure 2 and Table 1).


Genomic and physiological variability within Group II (non-proteolytic) Clostridium botulinum.

Stringer SC, Carter AT, Webb MD, Wachnicka E, Crossman LC, Sebaihia M, Peck MW - BMC Genomics (2013)

Venn diagram showing the relatedness of Group II C. botulinum strains. Orthologous CDSs were calculated between the three available Group II C. botulinum genome sequences by reciprocal FASTA best match analysis. CDSs shared between specific strains and CDSs unique to a particular strain are plotted on the Venn diagram.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3672017&req=5

Figure 2: Venn diagram showing the relatedness of Group II C. botulinum strains. Orthologous CDSs were calculated between the three available Group II C. botulinum genome sequences by reciprocal FASTA best match analysis. CDSs shared between specific strains and CDSs unique to a particular strain are plotted on the Venn diagram.
Mentions: Regions that were unique to the Eklund 17B (NRP) genome but were not associated with phage were also detected. Many of these regions carry CDSs for enzymes involved in metabolic pathways, regulators and transporters. Other regions specify cell envelope components. Specific unique CDSs include cold shock and heat shock proteins. A CDS for a predicted protein with similarity to an endolysin from C. beijerinckii, a septicolysin similar to that from C. septicum and a CDS sharing significant similarity with an internalin from Listeria ivanovii is also present. A Venn diagram was formulated to represent the number of CDS shared between the three sequenced Group II C. botulinum strains and the numbers of unique CDS (Figure 2). A total of 2521 CDS were common to all three strains out of a total of between 3257 and 3684 CDS (Figure 2 and Table 1).

Bottom Line: These results were compared with characteristics determined from physiological tests.However, these two subsets did not differ strongly in minimum growth temperature or maximum NaCl concentration for growth.No relationship was found between tellurite resistance and toxin type despite all the tested type B and type F strains carrying tehB, while the sequence was absent or diverged in all type E strains.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Food Research (IFR), Norwich Research Park, Colney, Norwich NR4 7UA, UK. sandra.stringer@ifr.ac.uk

ABSTRACT

Background: Clostridium botulinum is a group of four physiologically and phylogenetically distinct bacteria that produce botulinum neurotoxin. While studies have characterised variability between strains of Group I (proteolytic) C. botulinum, the genetic and physiological variability and relationships between strains within Group II (non-proteolytic) C. botulinum are not well understood. In this study the genome of Group II strain C. botulinum Eklund 17B (NRP) was sequenced and used to construct a whole genome DNA microarray. This was used in a comparative genomic indexing study to compare the relatedness of 43 strains of Group II C. botulinum (14 type B, 24 type E and 5 type F). These results were compared with characteristics determined from physiological tests.

Results: Whole genome indexing showed that strains of Group II C. botulinum isolated from a wide variety of environments over more than 75 years clustered together indicating the genetic background of Group II C. botulinum is stable. Further analysis showed that strains forming type B or type F toxin are closely related with only toxin cluster genes targets being unique to either type. Strains producing type E toxin formed a separate subset. Carbohydrate fermentation tests supported the observation that type B and F strains form a separate subset to type E strains. All the type F strains and most of type B strains produced acid from amylopectin, amylose and glycogen whereas type E strains did not. However, these two subsets did not differ strongly in minimum growth temperature or maximum NaCl concentration for growth. No relationship was found between tellurite resistance and toxin type despite all the tested type B and type F strains carrying tehB, while the sequence was absent or diverged in all type E strains.

Conclusions: Although Group II C. botulinum form a tight genetic group, genomic and physiological analysis indicates there are two distinct subsets within this group. All type B strains and type F strains are in one subset and all type E strains in the other.

Show MeSH
Related in: MedlinePlus