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Biological Terrorist Agents
Published in Robert A. Burke, Counter-Terrorism for Emergency Responders, 2017
A. precatorius (Figure 9.27): It has a median toxic dose of 0.7 μg/kg of body mass when given to mice intravenously (approximately 31.4 times more toxic than ricin being 22 μg/kg). The median toxic dose for humans ranges from 10 to 1,000 μg/kg when ingested and is 3.3 μg/kg when inhaled. Abrin, like ricin, is a ribosome-inhibiting protein and the toxin can also be found in the seeds of the castor bean plant. It is classified as a “Select Agent” under U.S. law. Abrin is a water-soluble lectin. Abrin in powdered form is yellowish-white. It is a stable substance and can withstand extreme environmental conditions. Though it is combustible, it does not polymerize easily and is not particularly volatile. Abrin (and ricin) may cause severe allergic reactions. Exposure to even a small amount of abrin may be fatal. Abrin is not known to have been weaponized. Abrin naturally occurs in the seeds of the rosary pea, a plant common to tropical regions, including the Southern United States that is occasionally employed as an herbal remedy for certain conditions. While the outer shell of the seed protects its contents from the stomachs of most mammals, they are occasionally punctured to make beaded jewelry (Figure 9.26). This can lead to poisoning if one is swallowed, or if a piece of such jewelry is worn against damaged skin. Abrin has been shown to act as an immunoadjuvant in the treatment of cancer in mice.
Nanomaterials Application in Biological Sensing of Biothreat Agents
Published in Jayeeta Chattopadhyay, Nimmy Srivastava, Application of Nanomaterials in Chemical Sensors and Biosensors, 2021
Jayeeta Chattopadhyay, Nimmy Srivastava
➢ Abrin—It is a ribosome-inactivating toxic protein extracted from plant Abrus precatorius (Lin et al. 1970). It is also the most probable candidate for use as a biothreat agent having toxic characterization the same as Ricin, but at the same time, it is 75% more toxic than Ricin (Patocka 2001).
Recognition of Adenine-like Rings by the Abrin—A Binding Site: A Flexible Docking Approach
Published in Devrim Balköse, Ana Cristina Faria Ribeiro, A. K. Haghi, Suresh C. Ameta, Tanmoy Chakraborty, Chemical Science and Engineering Technology, 2019
Ashima Bagaria, Mukesh Saran, Jagdish Parihar
In recent years, these plant RIPs which inhibit protein synthesis have become a subject of intense investigation not only because of the possible role played by them in synthesizing immunotoxins that are used in cancer therapy but also because they serve as model system for studying the molecular mechanism of transmembrane translocation of proteins.1,2 Abrin-a is one of the four isoabrins isolated from the seeds of Abrus precatorius and is anticarcinogenic.3,4 The anticarcinogenic activity includes the inhibition of protein biosynthesis5 by the cleavage of N-glycosidase bond of adenosine residue at position A43234 residues from 28 S rRNA.6 Depurination occurs at the first adenine, in the loop sequence GAGA, located in a highly conserved single stranded rRNA hairpin thereby arresting protein synthesis and causing cytotoxicity.6,7 Abrin-a is a heterodimer consisting of a cytotoxic A-chain linked by a disulfide bond to a B-chain, which binds to galactose residues present on various cell surface glycoproteins and glycolipids. The Abrin-a molecule shares major structural similarities with Ricin despite differences in their primary structures. The three-dimensional crystal structure of Abrin-a at 2.14 Å resolution has already been solved.8 The active site consists of the residues Tyr74, Tyr113, Glu164, Arg167, Trp198 and Asn72, Arg124, Gln160, Gln195 which are well conserved among all RIPs. Recent analysis of crystal structures of Ricin,9 Trichosanthin,10 pokeweed antiviral protein11 (PAP), Abrin-a,8A. precatorius agglutinin12 indicates that the overall architecture of the active site cleft remains constant in all these proteins. In Abrin-a, the aromatic rings of Tyr74 and Tyr113 are almost parallel. This orientation of both invariant tyrosine side-chains is most appropriate for sandwiching the planar adenine. In Ricin, PAP, and Trichosanthin, it is necessary to rotate the tyrosine side-chains to accommodate the adenine between them.13–15
An exploration on the toxicity mechanisms of phytotoxins and their potential utilities
Published in Critical Reviews in Environmental Science and Technology, 2022
Huiling Chen, Harpreet Singh, Neha Bhardwaj, Sanjeev K. Bhardwaj, Madhu Khatri, Ki-Hyun Kim, Wanxi Peng
Like plant RIPs, many similar proteins with N-glycosidic activity have been isolated from bacterial and fungal species. For example, Shiga and Shiga-like toxins (Stx 1 and Stx 2) were isolated from Shigella dysenteriae (Kavaliauskiene et al., 2017; Lee et al., 2016). They consist of an A chain with glycosidic activity and five binding chains (B fragments) that are covalently bonded to one another. Shiga toxins were first considered to be neurotoxins, but later studies revealed that they also have gastrointestinal effects (Sapountzis et al., 2020). The function and cytotoxic activity of Stx toxins are similar to those of ricin and abrin. They enter the cell cytosol through chaperones (LaPointe et al., 2005). These toxins cause apoptosis by damaging nucleic acids and activating caspase III (Shang et al., 2014). Another pathogen, Burkholderia pseudomallei produces a lethal RIP toxin called Burkholderia lethal factor 1 that terminates the helicase activity of RNA and indirectly inhibits the protein translation machinery (Hautbergue, 2012). Also, Aspergillus giganteus synthesizes a monomeric proteinaceous structure, α-sarcin, that belongs to a family of fungal ribotoxins. Instead of depurination (e.g., removing adenine from DNA), α-sarcin dissociates the sarcin/ricin loop to terminate the activation of elongation factors required to synthesize proteins (Olombrada et al., 2020). The cellular toxicity and pathogenesis caused by RIPs have been extensively reviewed (Griffiths, 2014; Spooner & Lord, 2014; Stirpe & Gilabert-Oriol, 2015; Zhu et al., 2018). Interest in RIPs is growing because of their wide applicability in medicine, agriculture, pharmaceutics, and human therapy, as discussed below.