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Ricin toxin toxicity

The effect of toxins such as melittin (from the honey-bee venom), myotoxin a, and cardiotoxin (from the snake venom) was investigated by vibrational spectroscopy (Pezolet et al., 1982 Faucon et ah, 1983 Liddle and Tu, 1985 Lafleur et ah, 1987). Monitoring the Raman intensity ratio I(1060)/I(1080) indicated that the lipid/melittin assemblies in DPPC are characterized by a high conformational order, little intermolecular chain-chain interaction, and a low cooperativity of the gel-like liquid crystalline phase transition. The effect of ricin, a toxic lectin, on DPPC and DPPC-cerebroside mixtures was studied by Raman and IR spectroscopy. It was suggested that ricin mainly interacts with the interfacial domains of the bilayers (Picquart et ah, 1989). [Pg.371]

Naturally occurring poisons which are also more potent than the nerve gases are found in such sources as snake venoms, among the substances known as arrow poisons, and among toxic proteins found naturally, such as ricin, the toxic protein of the castor bean, and the bacterial toxins, such as tetanus toxin and botulinum toxin. Few of these highly toxic substances appear at present to be useful per se as chemical warfare agents, but intensive research on any of them may well lead the chemist to new toxic substances with military practicality. [Pg.24]

Diagram 1. Representation of the ricin toxin subunit structure. The A-subunit is an enzyme and the B-subunit a lectin. The B-subunit plays a crucial role in binding to the cell surface thereby allowing the entry of the A-subunit into the cell. Once inside the cell the A-subunit separates and exerts its toxic effects. [Pg.320]

Toxins Toxic substance of natural origin produced by an animal, planf or microbe. They differ from chemical substances in that they are not manmade. Toxins may include botulism, ricin, and mycotoxins. [Pg.409]

Ricin toxin, found in the bean of the castor plant, Ricinis communis, is one of the most toxic and easily produced plant toxins. It is a lectin consisting of two polypeptide chains, the A-chain and the B-chain, linked by a disulfide bond. It is one of a group of dichain ribosome-inactivating proteins, which are specific for the depurination of a single adenosine in ribosomal ribonucleic acid (RNA).1 The active chain (ie, the A-chain) has the ability to modify catalytically the 28S subunit of... [Pg.632]

Ricin is a large, moderately toxic, protein dichain toxin from the bean of the castor plant, Ricinis communis. It can be produced easily in relatively large quantities. Ricin was developed as a biological weapon by the United States and its allies during World War II. Although ricin is toxic by several routes, when inhaled as a respirable aerosol, it causes severe necrosis of the airways and increased permeability of the alveolar-capillary membrane. The inhalational route... [Pg.639]

K Sandvig, S Olsnes. (1982). Entry of toxic proteins abrin, modeccin, ricin, and diphtheria toxin into cells. I. Requirement for Ca2+. J Biol Chem 257 7495-7503. [Pg.387]

Due to the extraordinary toxicity of intact ribosome-inactivating toxins like ricin, abrin, and modeccin, purification and handling of these proteins must be done with extreme care. Even dust from crude seed powders or lyophilized proteins should be considered dangerous. During... [Pg.828]

Several other inhibitors of protein synthesis are notable because of their toxicity to humans and other mammals. Diphtheria toxin (Mr 58,330) catalyzes the ADP-ribosylation of a diphthamide (a modified histidine) residue of eukaryotic elongation factor eEF2, thereby inactivating it. Ricin (Afr 29,895), an extremely toxic protein of the castor bean, inactivates the 60S subunit of eukaryotic ribosomes by depurinating a specific adenosine in 23S rRNA. [Pg.1067]

Ricin is a type II toxin. The A chain (ricin A) contains 267 amino acid residues, and the B chain (ricin B) 262 residues. Ricin A is exceptionally toxic, and it has been estimated that a single molecule is sufficient to kill an individual cell. This peptide can be prepared by genetic engineering using Escherichia coli. The potent action of this material on eukaryotic cells has been investigated in anticancer therapy. Ricin A has been coupled to monoclonal antibodies and successfully delivered specifically to the tumour cells. However, in vitro toxicity of ricin A-based immunotoxins is enhanced significantly if ricin B is also present. [Pg.434]

Endo, Y., Mitsui, K., Motizuki, M., and Tsurugi, K. (1987) The mechanism of action of ricin and related toxic lectins on eukaryotic ribosomes. The site and the characteristics of the modification in 28S ribosomal RNA caused by the toxins. J. Biol. Chem. 262, 5908-5912. [Pg.184]

The primary clinical targets of immunotoxins are tumors, based on the principle that the MAb will target the toxin to the tumor cells and the highly toxic moiety will then kill the cancer cells. Examples of toxins are ricin, diphtheria toxin and abrin, which are all glycoproteins. Their toxicity is based on their ability to block protein synthesis at the ribosomal protein assembly site. They are normally extremely toxic and not suitable for therapeutic purposes because they induce liver and vascular toxicity, even at low dose levels. [Pg.115]

Multiple purification-schemes have been applied to the separation of the toxin and the hemagglutinin.144,146,147,150,194,64,-651 Fractionation using salt and ethanol precipitation led to crystallization844,645 of the toxin known as ricin or ricin D. The hemagglutinin was isolated, free from toxic activity, by ion-exchange chromatography and gel filtration.642,646-648 With the introduction of affinity chromatography on Sepharose 4B, to which both proteins bind, purification of the two R. [Pg.270]

Chemicals come in all shapes and sizes and derive from a variety of sources. While to many people the words chemical and indeed poison are synonymous with man-made things such as dioxin, organo-phosphates, pesticides, and nerve gas, there are many, many other chemicals that occur naturally These may be produced by plants, for example belladonna in deadly nightshade, and ricin in the castor bean, or bacteria, for example botulinum toxin. Various animals such as snakes and spiders produce toxic venoms, and some poisons occur naturally in the ground, like asbestos, cadmium, and lead. [Pg.7]


See other pages where Ricin toxin toxicity is mentioned: [Pg.752]    [Pg.2]    [Pg.369]    [Pg.371]    [Pg.109]    [Pg.1]    [Pg.553]    [Pg.88]    [Pg.347]    [Pg.81]    [Pg.152]    [Pg.569]    [Pg.269]    [Pg.163]    [Pg.164]    [Pg.418]    [Pg.55]    [Pg.126]    [Pg.37]    [Pg.11]    [Pg.161]    [Pg.1685]    [Pg.1686]    [Pg.1686]    [Pg.151]    [Pg.518]    [Pg.434]    [Pg.434]    [Pg.155]    [Pg.259]    [Pg.121]    [Pg.88]    [Pg.651]    [Pg.736]    [Pg.503]    [Pg.255]   
See also in sourсe #XX -- [ Pg.633 ]




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Ricin

Ricin toxicity

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