STUDIES ON THE METABOLISM OF B. BOTULINUS IN VARIOUS MEDIA. XXVI

Proposed BoNT/A and /B Peptide Substrates Cannot Detect Multiple Subtypes in the Endopep-MS Assay

Botulinum neurotoxins (BoNTs) are a family of protein toxins consisting of seven known serotypes (BoNT/A-BoNT/G) and multiple subtypes within the serotypes, and all of which cause the disease botulism-a disease of great public health concern. Accurate detection of BoNTs in human clinical samples is therefore an important public health goal. To achieve this goal, our laboratory developed a mass spectrometry-based assay detecting the presence of BoNT via its enzymatic activity on a peptide substrate. Recently, publications reported the use of new peptide substrates to detect BoNT/A and /B with improved results over other peptide substrates. However, the authors did not provide results of their peptide substrate on multiple subtypes of BoNT. In this work, we describe the results of testing the new substrates with multiple BoNT/A and /B subtypes and find that the substrates cannot detect many subtypes of BoNT/A and /B.

Human and animal health on three continents--a biography of the early life of Karl Friedrich Meyer (1884-1974)

Karl Friedrich Meyer (KF) was born and educated as a veterinarian in Europe; he researched infectious diseases in Europe, South Africa and the United States. He is one of the true forefathers of the 'one health-one medicine' concept. The broad scope of his research covered botulism, leptospirosis, brucellosis, plague, ornithosis, Western equine encephalitis, mussel poisoning and clostridia. This manuscript adds some more details of his early biography.

Mass Spectrometric Identification and Differentiation of Botulinum Neurotoxins through Toxin Proteomics

Botulinum neurotoxins (BoNTs) cause the disease botulism, which can be lethal if untreated. There are seven known serotypes of BoNT, A-G, defined by their response to antisera. Many serotypes are distinguished into differing subtypes based on amino acid sequence and immunogenic properties, and some subtypes are further differentiated into toxin variants. Toxin characterization is important as different types of BoNT can respond differently to medical countermeasures for botulism, and characterization of the toxin can aid in epidemiologic and forensic investigations. Proteomic techniques have been established to determine the serotype, subtype, or toxin variant of BoNT. These techniques involve digestion of the toxin into peptides, tandem mass spectrometric (MS/MS) analysis of the peptides, and database searching to identify the BoNT protein. These techniques demonstrate the capability to detect BoNT and its neurotoxin-associated proteins, and differentiate the toxin from other toxins which are up to 99.9% identical in some cases. This differentiation can be accomplished from toxins present in a complex matrix such as stool, food, or bacterial cultures and no DNA is required.

De novo subtype and strain identification of botulinum neurotoxin type B through toxin proteomics

Botulinum neurotoxins (BoNTs) cause the disease botulism, which can be lethal if untreated. There are seven known serotypes of BoNT, A–G, defined by their response to antisera. Many serotypes are distinguished into differing subtypes based on amino acid sequence, and many subtypes are further differentiated into toxin variants. Previous work in our laboratory described the use of a proteomics approach to distinguish subtype BoNT/A1 from BoNT/A2 where BoNT identities were confirmed after searching data against a database containing protein sequences of all known BoNT/A subtypes. We now describe here a similar approach to differentiate subtypes BoNT/B1, /B2, /B3, /B4, and /B5. Additionally, to identify new subtypes or hitherto unpublished amino acid substitutions, we created an amino acid substitution database covering every possible amino acid change. We used this database to differentiate multiple toxin variants within subtypes of BoNT/B1 and B2. More importantly, with our amino acid substitution database, we were able to identify a novel BoNT/B subtype, designated here as BoNT/B7. These techniques allow for subtype and strain level identification of both known and unknown BoNT/B rapidly with no DNA required.

Figure

Some bacteriological aspects of dehydrated foods

1. Data on the maximum temperatures of growth of certain organisms, on the rate of toxin production byCl. botulinumand the rate of multiplication of certain Salmonellas, is given, as a basis on which to define the time and temperature of dehydration in the preparation of dehydrated foods.

2. It is concluded that 50° C. is the minimum temperature below which dehydration should not be carried out. Where some heating below this temperature is unavoidable, the period of such heating should not exceed 4 hr.

3. Data on the microbial changes in dehydrated foods equilibrated at various humidities indicate that bacterial growth is not expected below about 15 % water content. Some experiments on the death of bacteria at water levels below this are discussed.

4. Details are given of the general bacteriological examination of the process of dehydration on a commercial scale for dried soup, dried minced beef, dried carrot, cabbage and potato.

This work was carried out under the joint auspices of the Food Investigation Board of the Department of Scientific and Industrial Research, and the Ministry of Food, and is published by permission. The authors are indebted to Professor H. R. Dean for the provision of facilities, and to him, Professor G. S. Wilson, Dr A. W. Downie, and various other members of the Emergency Public Health Laboratory Service for help and advice.

STUDIES ON BACTERIAL ENZYMES : IV. THE MALTASE AND LIPASE OF THE BOTULINUS BACILLUS

Botulinus bacilli yield a maltase and a lipase, which retain their hydrolytic activity independent of the presence of the formed bacterial cell. The maltase is an endocellular substance, while the lipase is extracellular. The lipase, when separated from the anaerobic bacillus, does not seem to be affected by exposure to air.