Clostridium botulinum inhibition

Small GTPases of the Rho family are ADP-ribosylated (e.g., at Asn4l of RhoA) and inactivated by C3-like toxins from Clostridium botulinum, Clostridium limosum, and Staphylococcus aureus. These proteins have a molecular mass of 23-30 kDa and consist only of the enzyme domain. Specific inhibition of Rho functions (Rho but not Rac or Cdc42 are targets) is the reason why C3 is widely used as a pharmacological tool [2]. 

Similar to catechins, several studies have reported that proanthocyanidins exhibit a more or less pronoimced antibacterial activity. Chimg et al. [76] reported that proanthocyanidins determine the growth inhibition of strains of Aeromonas spp.. Bacillus spp., Clostridium botulinum, Clostridium per-fringens, Enterobacter spp., Klebsiella spp., Proteus spp.. Pseudomonas spp.. Shigella spp., S. aureus. Streptococcus spp., and Vibrio spp. 

Chaddock, J.A., Purkiss, J.R., Friis, L.M., Broadbridge, J.D., Duggan, M.J. Fooks, S.J., Shone, C.C., Quinn, C.P. and Foster, K.A., Inhibition of vesicular secretion in both neuronal and nonneuronal cells by a retargeted endopeptidase derivate of Clostridium botulinum neurotoxin type A, Infect. Immun., 68, 2587-2593, 2000. 

Rodgers, S., Peiris, P. and Casadei, G., Inhibition of nonproteolytic Clostridium botulinum with lactic acid bacteria and their bacteriocins at refrigeration temperatures, J. Food Prot., 66, 674-678, 2003. 

Smith, L.D.S., Inhibition of Clostridium botulinum by strains of Clostridium perfringens isolated from soil, Appl. Microbiol., 30, 319-323, 1975. 

In meat curing, nitrite is traditionally used for developing the pink, heat-stable pigment. Its other important role is the inhibition of the outgrowth of Clostridium botulinum spores in pasteurized products and, in some countries, in several types of smoked fish. Nitrite also serves as an antioxidant and contributes positively to the development of the flavor of cured-meat. The undesirable side-effect, however, is the reaction of nitrite with amino groups of food constituents, leading to the formation of NNCs. 

Botulism is most commonly caused by ingestion of a neurotoxin produced by Clostridium botulinum in improperly canned food. Poisoning may also occur after wound contamination with the organism. Infant botulism may occur when spores of the organism germinate and manufacture the toxin in the intestinal tract of infants. Botulinum toxin works by inhibiting ACh release at all cholinergic synapses. 

Acetylcholine release is inhibited by one of the most potent toxins, the botulims toxin produced by the anaerobic bacterium Clostridium botulinum. The toxin, lethal at 1 ng/kg in humans, enters the synapse by endocytosis at nonmyelinated synaptic membranes and produces muscle paralysis by blocking the active zone of the presynaptic membrane... 

Reddy, D., Lancaster, J. R., Jr., and Comforth, D. P. (1983). Nitrite inhibition of Clostridium botulinum Electron spin resonance detection of iron-nitric oxide complexes. Science 221, 769-770. 

Benedict, R. C. (1980). Biochemical basis for nitrite inhibition of Clostridium botulinum in cured meat. J. Food Protection 43, 877-891. 

Johnson, M. A., Pivnick, H., and Samson, J. M. (1969). Inhibition of Clostridium botulinum by sodium nitrite in a bacteriological medium and meat. Can. Inst. Food Technol. J. 

Grecz, N., Wagenaar, R. O. and Dack, G. M. 1959. Inhibition of Clostridium botulinum by culture filtrates of Brevibacterium linens. J. Bacteriol. 78, 506-510. 

Nitrosamines can be formed when amines that occur naturally in food react with sodium nitrite, NaN02, a preservative added to meats such as ham, bacon, and hot dogs to inhibit the growth of Clostridium botulinum, a bacterium responsible for a lethal form of food poisoning. Nitrosamines may also be formed in vivo in the gastrointestinal tract when bacteria in the body convert nitrates (N03 ) into nitrites (NO2 ), which then react with amines. 

Reuner KH, Schlegel K, Just I, et al. (1991) Autoregulatory control of actin synthesis in cultured rat hepatocytes. In FEBS Letters. 286 100-4 Schmid A, Benz R, Just I, et al. (1994) Interaction of Olostridium botulinum 02 toxin with lipid bilayer membranes. Formation of cation-selective channels and inhibition of channel function by chloroquine. In J Biol Chem. 269 16706-11 Simpson LL (1982) A comparison of the pharmacological properties of Clostridium botulinum type 01 and 02 toxins. In J Pharmacol Exp Then 223 695-701 Simpson LL (1989a) Botulinum Neurotoxin andTetanus Toxin, pp 1 -422, San Diego Academic Press... 

Exocytosis targeted exocytotoxins. a-Latrotoxin (black widow spider venom) causes a massive exocytotic release, followed by depletion of acetylcholine and other neurotransmitters. Botulinum toxins (A, B,C, D, E, F. G serotypes) are peptide exotoxins elaborated by a bacterium [Clostridium botulinum) that cause flaccid paralysis through inhibition of depolarization-induced release of acetylcholine at the skeletal neuromuscular junction. Tetanus toxin elaborated by bacterium [Clostridium tetani), is a polypeptide A-B exotoxin transported retrogradely along sensory neurons to the CNS, leading to tetanic paralysis. 

Lysozyme, which makes up 3.5% of the total egg white proteins and can be easily separated by ion-exchange techniques (Lesnierowski and Kijowski, 2001), is recognized as a safe, antimicrobial agent to be used for food preservation. It is stable up to about 100°C, has maximum activity at a pH range of 5.3-6.4, and inhibits several pathogenic bacteria, including Listeria monocytogenes, Clostridium botulinum, Yersinia enterocolitica, and Campylobacter jejuni (Kijowski and Lesnierowski, 1999). 

Some decades later, nitrite was recognized as a potent inhibitor of microorganisms, including pathogens, in many meat products. In particular, the inhibition of Clostridium botulinum, with accompanying toxin formation, was established. The role of nitrite in the characteristic cured meat flavor was still noticed later on. 

The presence of nitrites has both a positive and negative impact on food safety. On one hand, in many countries, a correlation between stomach and liver cancers, induced probably by nitrosamines, and the amount of nitrites consumed is observed (Fine et al., 1982). On the other hand, nitrites inhibit the growth of Clostridium botulinum, thus reducing the risk of food contamination by botulinum toxins. Moreover, under the acidic conditions of the stomach, where they are involved in the formation of carcinogenic nitrosamines, nitrites are capable of neutralizing carcinogens formed as a result of protein pyrolysis (Pariza, 1982). 

The botulinum neurotoxins (BoNTs) comprise a family of seven distinct neurotoxic proteins (A-G) produced by immunologically discrete strains of the anaerobic bacterium Clostridium botulinum and in rare cases by Clostridium baratii and Clostridium butyricum (Habermann and Dreyer, 1986 Harvey et ah, 2002 Simpson, 2004). These toxins act on peripheral cholinergic synapses to inhibit spontaneous and impulse-dependent release of acetylcholine (ACh) (Brooks, 1956 Kao et al., 1976). Intoxication by BoNT results in muscle weakness, which can be fatal when the diaphragm and intercostal muscles become sufficiently compromised to impair ventilation (Dickson and Shevky, 1923). The BoNTs are the most potent substances in nature, and exposure to as httle as 1-3 ng/kg may be sufficient to cause human lethahty (GUI, 1982 Middlebrook and Franz, 1997 Amon et al., 2001). 

Several toxic proteins act as neurotoxins by disrupting the activity of synapses. (A synapse is a junction between two neurons or between a neuron and a muscle cell.) The pain, tremors, and irritability that result from black widow spider bites are caused by a-latrotoxin (125,000 D). This molecule, a single polypeptide, stimulates a massive release of the neurotransmitter acetylcholine (ACh). In contrast, ACh release is inhibited by botulinum toxin, a mixture of several proteins produced by the bacterium Clostridium botulinum. Botulism, a malady most commonly caused by eating contaminated canned food, is characterized by vomiting, dizziness, and sometimes paralysis and death. A related species,... 

The release of ACh and other neurotransmitters by exocytosis is inhibited by botulinum and tetanus toxins from Clostridium. Botulinum toxin acts in the nerve ending to reduce ACh vesicular release (see Chapters 9 and 63 for therapeutic uses of botulinum toxin). 

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