Current Methods for Detecting the Presence of Botulinum Neurotoxins in Food and Other Biological Samples

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Technologies for Detecting Botulinum Neurotoxins in Biological and Environmental Matrices

Biomonitoring of food and environmental matrices is critical for the rapid and sensitive diagnosis, treatment, and prevention of diseases caused by toxins. The U.S. Centers for Disease Control and Prevention (CDC) has noted that toxins from bacteria, fungi, algae, and plants present an ongoing public health threat, especially since some of these toxins could compromise security of the food supply. Botulinum neurotoxins (BoNTs), produced by Clostridium spp., are among those bacterial toxins that pose life-threatening danger to humans. BoNTs inhibit the release of acetylcholine at peripheral cholinergic nerve terminals and cause flaccid paralysis. BoNTs are grouped in seven serotypes and many subtypes within these groups. Rapid and accurate identification of these toxins in contaminated food as well as in environmental matrices can help direct treatment. Herein, we discuss current methods to detect BoNTs with a focus on how these technologies have been used to identify toxins in various food and environmental matrices. We also discuss the emergence of new serotypes and subtypes of BoNTs and the increasing number of cases of botulism in wildlife. Finally, we consider how environmental changes impact food safety for humans and present new challenges for detection technology

Detection of Botulinum Neurotoxin Serotype B at Sub Mouse LD50 Levels by a Sandwich Immunoassay and Its Application to Toxin Detection in Milk

Botulinum neurotoxin (BoNT), the causative agent of botulism, a serious neuroparylatic disease, is produced by the anaerobic bacterium Clostridium botulinum and consists of a family of seven serotypes (A-H). We previously reported production of high-affinity monoclonal antibodies to BoNT serotype A.Recombinant peptide fragments of the light chain, the transmembrane and receptor-binding domains of the heavy chain of botulinum neurotoxin type B (BoNT/B) were expressed in Escherichia coli as GST-fusion proteins and purified. These proteins were used to immunize BALB/cJ mice for the generation of monoclonal antibodies (mAbs). Antibody-producing hybridomas were detected using either a direct binding ELISA binding to plate-immobilized BoNT/B, or with a capture-capture ELISA whereby the capacity of the antibody to capture BoNT/B from solution was tested. A total of five mAbs were selected, two of which bound the toxin light chain and three bound the receptor-binding domain of BoNT/B heavy chain. MAb MCS6-27 was identified via capture-capture ELISA and was the only mAb able to bind BoNT/B in solution under physiological conditions. MAbs F24-1, F26-16, F27-33 and F29-40 were identified via direct binding ELISA, and were able to capture BoNT/B in solution only in the presence of 0.5-0.9 mM sodium dodecyl sulphate (SDS). MAb MCS6-27 and an anti-BoNT/B polyclonal antibody were incorporated into a sandwich ELISA that did not require SDS.We report here the generation of monoclonal antibodies to serotype B and the subsequent development of a sensitive sandwich immunoassay. This immunoassay has a detection limit of 100 fg BoNT/B, fifty times more sensitive than the mouse bioassay detection limit of 5 pg BoNT/B. Additionally, this assay detected as little as 39 pg/mL of toxin in skim, 2% and whole milk

The complete genome sequence and analysis of the Epsilonproteobacterium \u3cem\u3eArcobacter butzleri\u3c/em\u3e

Arcobacter butzleri is a member of the epsilon subdivision of the Proteobacteria and a close taxonomic relative of established pathogens, such as Campylobacter jejuni and Helicobacter pylori. Here we present the complete genome sequence of the human clinical isolate, A. butzleri strain RM4018. Methodology/Principal Findings: Arcobacter butzleri is a member of the Campylobacteraceae, but the majority of its proteome is most similar to those of Sulfuromonas denitrificans and Wolinella succinogenes, both members of the Helicobacteraceae, and those of the deep-sea vent Epsilonproteobacteria Sulfurovum and Nitratiruptor. In addition, many of the genes and pathways described here, e.g. those involved in signal transduction and sulfur metabolism, have been identified previously within the epsilon subdivision only in S. denitrificans, W. succinogenes, Sulfurovum, and/or Nitratiruptor, or are unique to the subdivision. In addition, the analyses indicated also that a substantial proportion of the A. butzleri genome is devoted to growth and survival under diverse environmental conditions, with a large number of respiration-associated proteins, signal transduction and chemotaxis proteins and proteins involved in DNA repair and adaptation. To investigate the genomic diversity of A. butzleri strains, we constructed an A. butzleri DNA microarray comprising 2238 genes from strain RM4018. Comparative genomic indexing analysis of 12 additional A. butzleri strains identified both the core genes of A. butzleri and intraspecies hypervariable regions, where, 70% of the genes were present in at least two strains. Conclusion/Significance: The presence of pathways and loci associated often with non-hostassociated organisms, as well as genes associated with virulence, suggests that A. butzleri is a free-living, water-borne organism that might be classified rightfully as an emerging pathogen. The genome sequence and analyses presented in this study are an important first step in understanding the physiology and genetics of this organism, which constitutes a bridge between the environment and mammalian hosts

The Complete Genome Sequence and Analysis of the Epsilonproteobacterium Arcobacter butzleri

BACKGROUND: Arcobacter butzleri is a member of the epsilon subdivision of the Proteobacteria and a close taxonomic relative of established pathogens, such as Campylobacter jejuni and Helicobacter pylori. Here we present the complete genome sequence of the human clinical isolate, A. butzleri strain RM4018. METHODOLOGY/PRINCIPAL FINDINGS: Arcobacter butzleri is a member of the Campylobacteraceae, but the majority of its proteome is most similar to those of Sulfuromonas denitrificans and Wolinella succinogenes, both members of the Helicobacteraceae, and those of the deep-sea vent Epsilonproteobacteria Sulfurovum and Nitratiruptor. In addition, many of the genes and pathways described here, e.g. those involved in signal transduction and sulfur metabolism, have been identified previously within the epsilon subdivision only in S. denitrificans, W. succinogenes, Sulfurovum, and/or Nitratiruptor, or are unique to the subdivision. In addition, the analyses indicated also that a substantial proportion of the A. butzleri genome is devoted to growth and survival under diverse environmental conditions, with a large number of respiration-associated proteins, signal transduction and chemotaxis proteins and proteins involved in DNA repair and adaptation. To investigate the genomic diversity of A. butzleri strains, we constructed an A. butzleri DNA microarray comprising 2238 genes from strain RM4018. Comparative genomic indexing analysis of 12 additional A. butzleri strains identified both the core genes of A. butzleri and intraspecies hypervariable regions, where <70% of the genes were present in at least two strains. CONCLUSION/SIGNIFICANCE: The presence of pathways and loci associated often with non-host-associated organisms, as well as genes associated with virulence, suggests that A. butzleri is a free-living, water-borne organism that might be classified rightfully as an emerging pathogen. The genome sequence and analyses presented in this study are an important first step in understanding the physiology and genetics of this organism, which constitutes a bridge between the environment and mammalian hosts

Botulinum Neurotoxin Detection Methods for Public Health Response and Surveillance

Botulism outbreak due to consumption of food contaminated with botulinum neurotoxins (BoNTs) is a public health emergency. The threat of bioterrorism through deliberate distribution in food sources and/or aerosolization of BoNTs raises global public health and security concerns due to the potential for high mortality and morbidity. Rapid and reliable detection methods are necessary to support clinical diagnosis and surveillance for identifying the source of contamination, performing epidemiological analysis of the outbreak, preventing and responding to botulism outbreaks. This review considers the applicability of various BoNT detection methods and examines their fitness-for-purpose in safeguarding the public health and security goals

Partial Characterization of a Eukaryotic Algal Virus Infecting the Green Alga Cylindrocapsa Geminella

144 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1980.A virus infecting single-celled germlings of the green alga Cylindrocapsa geminella Wolle has been isolated and partially characterized. The virus, designated as the Cylindrocapsa virus (CV), has a 5- or 6-sided polygonal profile in sectional view suggesting that it has an icosahedral geometryU of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD