Andrew T Carter

Publications (11)50.14 Total impact

• Article: The type F6 neurotoxin gene cluster locus of Group II Clostridium botulinum has evolved by successive disruption of two different ancestral precursors.

  Andrew T Carter, Sandra C Stringer, Martin D Webb, Michael W Peck
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  ABSTRACT: Genome sequences of five different Group II (non-proteolytic) Clostridium botulinum type F6 strains were compared at a 50 kb locus containing the neurotoxin gene cluster. A clonal origin for these strains is indicated by the fact that sequences were identical except for strain Eklund 202F, with 10 SNPs and a 15bp deletion. The essential topB gene encoding topoisomerase III was found to have been split by the apparent insertion of 34.4 kb of foreign DNA (in a similar manner to that in Group II C. botulinum type E where the rarA gene has been disrupted by a neurotoxin gene cluster). The foreign DNA, which includes the intact 13.6 kb type F6 neurotoxin gene cluster, bears not only a newly introduced topB gene, but also two non-functional botulinum neurotoxin gene remnants, a type B and a type E. This observation, combined with the discovery of bacteriophage integrase genes and IS4 elements suggest that several rounds of recombination/horizontal gene transfer have occurred at this locus. The simplest explanation for the current genotype is that the ancestral bacterium, a Group II C. botulinum type B strain, received DNA firstly from a strain containing a type E neurotoxin gene cluster, then from a strain containing a type F6 neurotoxin gene cluster. Each event disrupted the previously functional neurotoxin gene. This degree of successive recombination at one hot-spot is without precedent in C. botulinum, and it is also the first description of a Group II C. botulinum genome containing more than one neurotoxin gene sequence.
  Genome Biology and Evolution 05/2013; · 4.62 Impact Factor
• Article: Clostridium botulinum in the post-genomic era.

  Michael W Peck, Sandra C Stringer, Andrew T Carter
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  ABSTRACT: Foodborne botulism is a severe neuroparalytic disease caused by consumption of botulinum neurotoxin formed by strains of proteolytic Clostridium botulinum and non-proteolytic C. botulinum during their growth in food. The botulinum neurotoxin is the most potent substance known, with as little as 30-100 ng potentially fatal, and consumption of just a few milligrams of neurotoxin-containing food is likely to be sufficient to cause illness and potentially death. In order to minimise the foodborne botulism hazard, it is necessary to extend understanding of the biology of these bacteria. This process has been recently advanced by genome sequencing and subsequent analysis. In addition to neurotoxin formation, endospore formation is also critical to the success of proteolytic C. botulinum and non-proteolytic C. botulinum as foodborne pathogens. The endospores are highly resistant, and enable survival of adverse treatments such as heating. To better control the botulinum neurotoxin-forming clostridia, it is important to understand spore resistance mechanisms, and the physiological processes involved in germination and lag phase during recovery from this dormant state.
  Food Microbiology 04/2011; 28(2):183-91. · 3.28 Impact Factor
• Article: Complete genome sequence of the proteolytic Clostridium botulinum type A5 (B3') strain H04402 065.

  Andrew T Carter, Bruce M Pearson, Lisa C Crossman, Nizar Drou, Darren Heavens, David Baker, Melanie Febrer, Mario Caccamo, Kathie A Grant, Michael W Peck
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  ABSTRACT: H04402 065 is one of a very small group of strains of proteolytic Clostridium botulinum that form type A5 neurotoxin. Here, we report the complete 3.9-Mb genome sequence and annotation of strain H04402 065, which was isolated from a botulism patient in the United Kingdom in 2004.
  Journal of bacteriology 03/2011; 193(9):2351-2. · 3.94 Impact Factor
• Article: Further characterization of proteolytic Clostridium botulinum type A5 reveals that neurotoxin formation is unaffected by loss of the cntR (botR) promoter sigma factor binding site.

  Andrew T Carter, David R Mason, Kathie A Grant, Giovanna Franciosa, Paulo Aureli, Michael W Peck
  Journal of clinical microbiology 03/2010; 48(3):1012-3. · 4.16 Impact Factor
• Article: Effects of carbon dioxide on growth of proteolytic Clostridium botulinum, its ability to produce neurotoxin, and its transcriptome.

  Ingrid Artin, David R Mason, Carmen Pin, Jenny Schelin, Michael W Peck, Elisabet Holst, Peter Rådström, Andrew T Carter
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  ABSTRACT: The antimicrobial gas carbon dioxide is frequently used in modified atmosphere packaging. In the present study, the effects of CO2 (10 to 70%, vol/vol) on gene expression (measured using quantitative reverse transcription-PCR and a whole-genome DNA microarray) and neurotoxin formation (measured using an enzyme-linked immunosorbent assay [ELISA]) by proteolytic Clostridium botulinum type A1 strain ATCC 3502 were studied during the growth cycle. Interestingly, in marked contrast to the situation with nonproteolytic C. botulinum types B and E, CO2 had little effect on any of these parameters. At all CO2 concentrations, relative expression of neurotoxin cluster genes peaked in the transition between exponential and stationary phases, with evidence of a second rise in expression in late stationary phase. Microarray analysis enabled identification of coding sequences whose expression profiles matched those of the neurotoxin cluster. Further research is needed to determine whether these are connected to neurotoxin formation or are merely growth phase associated.
  Applied and environmental microbiology 02/2010; 76(4):1168-72. · 3.69 Impact Factor
• Article: Comparative genomic hybridization analysis of two predominant Nordic group I (proteolytic) Clostridium botulinum type B clusters.

  Miia Lindström, Katja Hinderink, Panu Somervuo, Katri Kiviniemi, Mari Nevas, Ying Chen, Petri Auvinen, Andrew T Carter, David R Mason, Michael W Peck, Hannu Korkeala
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  ABSTRACT: Comparative genomic hybridization analysis of 32 Nordic group I Clostridium botulinum type B strains isolated from various sources revealed two homogeneous clusters, clusters BI and BII. The type B strains differed from reference strain ATCC 3502 by 413 coding sequence (CDS) probes, sharing 88% of all the ATCC 3502 genes represented on the microarray. The two Nordic type B clusters differed from each other by their response to 145 CDS probes related mainly to transport and binding, adaptive mechanisms, fatty acid biosynthesis, the cell membranes, bacteriophages, and transposon-related elements. The most prominent differences between the two clusters were related to resistance to toxic compounds frequently found in the environment, such as arsenic and cadmium, reflecting different adaptive responses in the evolution of the two clusters. Other relatively variable CDS groups were related to surface structures and the gram-positive cell wall, suggesting that the two clusters possess different antigenic properties. All the type B strains carried CDSs putatively related to capsule formation, which may play a role in adaptation to different environmental and clinical niches. Sequencing showed that representative strains of the two type B clusters both carried subtype B2 neurotoxin genes. As many of the type B strains studied have been isolated from foods or associated with botulism, it is expected that the two group I C. botulinum type B clusters present a public health hazard in Nordic countries. Knowing the genetic and physiological markers of these clusters will assist in targeting control measures against these pathogens.
  Applied and environmental microbiology 04/2009; 75(9):2643-51. · 3.69 Impact Factor
• Article: Effects of carbon dioxide on neurotoxin gene expression in nonproteolytic Clostridium botulinum Type E.

  Ingrid Artin, Andrew T Carter, Elisabet Holst, Maria Lövenklev, David R Mason, Michael W Peck, Peter Rådström
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  ABSTRACT: Carbon dioxide is an antimicrobial gas commonly used in modified atmosphere packaging. In the present study, the effects of carbon dioxide on the growth of and neurotoxin production by nonproteolytic Clostridium botulinum type E were studied during the growth cycle. Quantitative reverse transcription-PCR and an enzyme-linked immunosorbent assay were used to quantify expression of the type E botulinum neurotoxin gene (cntE) and the formation of type E neurotoxin. The expression levels of cntE were similar in two strains, with relative expression peaking in the transition between exponential phase and stationary phase. In stationary phase, cntE mRNA expression declined rapidly. The cntE mRNA half-life was calculated to be approximately 9 minutes. Neurotoxin formation occurred in late exponential phase and stationary phase. High carbon dioxide concentrations delayed growth by increasing the lag time and decreasing the maximum growth rate. The effects of carbon dioxide concentration on relative neurotoxin gene expression and neurotoxin formation were significant. Expression of cntE mRNA and the formation of extracellular neurotoxin were twofold higher with a headspace carbon dioxide concentration of 70% (vol/vol) compared to 10% (vol/vol). This finding sheds a new, cautionary light on the potential risks of botulism associated with the use of modified atmosphere packaging.
  Applied and environmental microbiology 05/2008; 74(8):2391-7. · 3.69 Impact Factor
• Article: Genome sequence of a proteolytic (Group I) Clostridium botulinum strain Hall A and comparative analysis of the clostridial genomes.

  Mohammed Sebaihia, Michael W Peck, Nigel P Minton, Nicholas R Thomson, Matthew T G Holden, Wilfrid J Mitchell, Andrew T Carter, Stephen D Bentley, David R Mason, Lisa Crossman, [......], Mark Maddison, Sharon Moule, Karen Mungall, Halina Norbertczak, Ester Rabbinowitsch, Mandy Sanders, Mark Simmonds, Brian White, Sally Whithead, Julian Parkhill
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  ABSTRACT: Clostridium botulinum is a heterogeneous Gram-positive species that comprises four genetically and physiologically distinct groups of bacteria that share the ability to produce botulinum neurotoxin, the most poisonous toxin known to man, and the causative agent of botulism, a severe disease of humans and animals. We report here the complete genome sequence of a representative of Group I (proteolytic) C. botulinum (strain Hall A, ATCC 3502). The genome consists of a chromosome (3,886,916 bp) and a plasmid (16,344 bp), which carry 3650 and 19 predicted genes, respectively. Consistent with the proteolytic phenotype of this strain, the genome harbors a large number of genes encoding secreted proteases and enzymes involved in uptake and metabolism of amino acids. The genome also reveals a hitherto unknown ability of C. botulinum to degrade chitin. There is a significant lack of recently acquired DNA, indicating a stable genomic content, in strong contrast to the fluid genome of Clostridium difficile, which can form longer-term relationships with its host. Overall, the genome indicates that C. botulinum is adapted to a saprophytic lifestyle both in soil and aquatic environments. This pathogen relies on its toxin to rapidly kill a wide range of prey species, and to gain access to nutrient sources, it releases a large number of extracellular enzymes to soften and destroy rotting or decayed tissues.
  Genome Research 08/2007; 17(7):1082-92. · 13.61 Impact Factor
• Article: Mucosal delivery of a pneumococcal vaccine using Lactococcus lactis affords protection against respiratory infection.

  Sean B Hanniffy, Andrew T Carter, Ed Hitchin, Jerry M Wells
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  ABSTRACT: Economical and effective vaccines against Streptococcus pneumoniae (pneumococcus) are needed for implementation in poorer countries where the disease burden is highest. Here, we evaluated Lactococcus lactis intracellularly producing the pneumococcal surface protein A (PspA) as a mucosal vaccine in conferring protection against pneumococcal disease. Mice were intranasally (inl) immunized with the lactococcal vaccine. Control groups were also immunized with similar amounts of recombinant PspA administered inl or subcutaneously with alum. PspA-specific antibodies in serum samples and lung lavage fluids were measured before challenge in intraperitoneal sepsis and inl respiratory-infection models of pneumococcal disease. The lactococcal vaccine afforded better protection against respiratory challenge with pneumococcus than did vaccination with purified antigen given inl or by injection with alum. This finding was associated with a shift toward a Th1-mediated immune response characterized by reduced antibody titers to the PspA antigen. In the sepsis model, the lactococcal vaccine afforded resistance to disease on a par with that obtained with the injected vaccine, demonstrating its efficacy against different forms of pneumococcal disease. Given the safety profile of L. lactis, there is considerable potential to develop a pneumococcal vaccine for use in humans and to broaden this approach to combat other major pathogens.
  The Journal of Infectious Diseases 02/2007; 195(2):185-93. · 6.41 Impact Factor
• Article: A third fatty acid delta9-desaturase from Mortierella alpina with a different substrate specificity to ole1p and ole2p.

  Donald A MacKenzie, Andrew T Carter, Prasert Wongwathanarat, John Eagles, Joanne Salt, David B Archer
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  ABSTRACT: A third gene (Delta9-3) encoding a fatty acid Delta9-desaturase was isolated from the oil-producing fungus Mortierella alpina. The predicted protein of 512 aa shared 53% sequence identity with the two fatty acid Delta9-desaturases, ole1p and ole2p, already described in this organism and contained three histidine boxes, four putative transmembrane domains and a C-terminal cytochrome b(5) fusion that are typical of most fungal membrane-bound fatty acid desaturases. However, unlike the M. alpina ole1 and ole2 genes, the Delta9-3 ORF failed to complement the Saccharomyces cerevisiae ole1 mutation. GC-MS analysis of fatty-acid-supplemented ole1 yeast transformants containing the Delta9-3 gene indicated that this enzyme had negligible activity with endogenous palmitic acid (16:0) as substrate and moderate activity (30-65% desaturation) with endogenous stearic acid (18:0). Yeast transformants overexpressing any one of the three M. alpina fatty acid Delta9-desaturase genes or the S. cerevisiae OLE1 gene produced low amounts of hexacosenoic acid [26:1(n-9)], a fatty acid that is not normally present in yeast cells. It follows that these Delta9-desaturases may also display low n-9 desaturation activity with very long-chain saturated fatty acid substrates. Conversely, high levels of desaturase in the endoplasmic reticulum membrane of these yeast transformants may increase the availability of suitable monounsaturated substrates for fatty acid elongation.
  Microbiology 07/2002; 148(Pt 6):1725-35. · 3.06 Impact Factor
• Article: Isolation and Use of a Homologous Histone H4 Promoter and a Ribosomal DNA Region in a Transformation Vector for the Oil-Producing Fungus Mortierella alpina

  Donald A Mackenzie, Prasert Wongwathanarat, Andrew T. Carter, David B Archer
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  ABSTRACT: Mortierella alpina was transformed successfully to hygromycin B resistance by using a homologous histone H4 promoter to drive gene expression and a homologous ribosomal DNA region to promote chromosomal integration. This is the first description of transformation in this commercially important oleaginous organism. Two pairs of histone H3 and H4 genes were isolated from this fungus. Each pair consisted of one histone H3 gene and one histone H4 gene, transcribed divergently from an intergenic promoter region. The pairs of encoded histone H3 or H4 proteins were identical in amino acid sequence. At the DNA level, each histone H3 or H4 open reading frame showed 97 to 99% identity to its counterpart but the noncoding regions had little sequence identity. Unlike the histone genes from other filamentous fungi, all four M. alpina genes lacked introns. During normal vegetative growth, transcripts from the two histone H4 genes were produced at approximately the same level, indicating that either histone H4 promoter could be used in transformation vectors. The generation of stable, hygromycin B-resistant transformants required the incorporation of a homologous ribosomal DNA region into the transformation vector to promote chromosomal integration.