Ricin
166470
225804026
2008-07-15T14:05:15Z
72.93.214.138
/* Patented extraction process */
[[Image:castor beans.jpg|thumb|300px|Castor beans]]
'''Ricin''' ({{pronEng|ˈraɪsɨn}}) is a [[protein]] [[toxin]] that is [[solvent extraction|extracted]] from the [[Castor oil plant|castor bean]] (''Ricinus communis'').
The [[U.S. Centers for Disease Control|U.S. Centers for Disease Control (CDC)]] gives a possible minimum figure of 500 micrograms (about the size of a grain of salt) {{Fact|date=May 2008}} for the [[lethal dose]] of ricin in humans if exposure is from [[injection]] or [[inhalation]].<ref name="http://www.bt.cdc.gov/agent/ricin/facts.asp">[http://www.bt.cdc.gov/agent/ricin/facts.asp http://www.bt.cdc.gov/agent/ricin/facts.asp]</ref>
==Toxicity==
[[Image:ricin structure.png|thumb|300px|Ricin structure. The '''A''' chain is shown in blue and the '''B''' chain in orange.]]
Ricin is poisonous if [[inhalation|inhaled]], [[Injection (medicine)|injected]], or [[ingestion|ingested]], acting as a toxin by the inhibition of [[protein biosynthesis|protein synthesis]]. While there is no known [[antidote]], the US military has developed a [[vaccine]].<ref>[http://www.dcmilitary.com/dcmilitary_archives/stories/090105/36813-1.shtml http://www.dcmilitary.com/dcmilitary_archives/stories/090105/36813-1.shtml]</ref> [[Symptom]]atic and supportive treatment is available. Long term [[Organ (anatomy)|organ]] damage is likely in survivors. Ricin causes severe [[diarrhea]] and victims can die of [[Shock (medical)|shock]]. [[Abrin]] is a similar toxin.
Deaths caused by ingestion of castor oil plant seeds are rare.<ref>{{cite journal |author=Aplin PJ, Eliseo T |title=Ingestion of castor oil plant seeds |journal=Med. J. Aust. |volume=167 |issue=5 |pages=260–1 |year=1997 |pmid=9315014 |doi=}}</ref> Eight beans are considered toxic for an adult.<ref>{{cite journal |author=Wedin GP, Neal JS, Everson GW, Krenzelok EP |title=Castor bean poisoning |journal=The American journal of emergency medicine |volume=4 |issue=3 |pages=259–61 |year=1986 |pmid=3964368|doi=10.1016/0735-6757(86)90080-X}}</ref> A solution of [[Saline (medicine)|saline]] and [[glucose]] has been used to treat ricin overdose.<ref>{{cite journal |author=Kopferschmitt J, Flesch F, Lugnier A, Sauder P, Jaeger A, Mantz JM |title=Acute voluntary intoxication by ricin |journal=Human toxicology |volume=2 |issue=2 |pages=239–42 |year=1983 |pmid=6862467 |doi=}}</ref> The case experience is not as negative as popular perception would indicate.<ref>{{cite journal |author=Rauber A, Heard J |title=Castor bean toxicity re-examined: a new perspective |journal=Veterinary and human toxicology |volume=27 |issue=6 |pages=498–502 |year=1985 |pmid=4082461 |doi=}}</ref>
==Biochemistry==
Ricin is classified as a type 2 ribosome inactivating protein (RIP). Whereas Type 1 RIPs consist of a single enzymatic protein chain, Type 2 RIPs, also known as holotoxins, are heterodimeric glycoproteins. Type 2 RIPs consist of an A chain that is functionally equivalent to a Type 1 RIP, covalently connected by a single disulfide bond to a B chain that is catalytically inactive, but serves to mediate entry of the A-B protein complex into the cytosol. Both Type 1 and Type 2 RIPs are functionally active against ribosomes in vitro, however only Type 2 RIPs display cytoxicity due to the lectin properties of the B chain. In order to display its ribosome inactivating function, the ricin disulfide bond must be reductively cleaved.<ref>{{cite journal |author=Wright HT, Robertus JD |title=The intersubunit disulfide bridge of ricin is essential for cytotoxicity |journal=Arch Biochem Biophys |pages=280–4 |year=1987 |volume=256 |doi=10.1016/0003-9861(87)90447-4}}</ref>
===Structure===
The tertiary structure of ricin was shown to be a globular, glycosylated heterodimer of approximately 60-65 kDA.[5] Ricin toxin A chain (RTA) and ricin toxin B chain (RTB) are of similar molecular weight, approximately 32 kDA and 34 kDA respectively.
* '''Ricin A Chain''' is an N-glycoside hydrolase composed of 267 amino acids.<ref>{{cite journal |author=Olnes S, Pihl A |title=Different biological properties of the two constituent peptide chains of ricin, a toxic protein inhibiting protein synthesis |journal=Biochemistry |volume=12 | pages=3121–26 |year=1973 |doi=10.1021/bi00740a028}}</ref> It has three structural domains with approximately 50% of the polypeptide arranged into alpha-helices and beta-sheets.<ref>{{cite journal |author=Weston SA, Tucker AD, Thatcher DR, et al. |title=X-ray structure of recombinant ricin A-chain at 1.8 A resolution |journal=J Mol Biol | volume=244 |pages=410–22 |year=1994 |doi=10.1006/jmbi.1994.1739}}</ref> The three domains form a pronounced cleft that is the active site of RTA.
* '''Ricin B Chain''' is a lectin composed of 262 amino acids that is able to bind terminal galactose residues on cell surfaces.<ref>{{cite journal |author=Wales R, Richardson PT, Robers LM, Woodland HR, et al. |title=Mutational analysis of the galactose binding ability of recombinant ricin b chain |journal=J Biol Chem |volume=266 | pages=19172–79 |year=1991}}</ref> RTB form a bilobal, barbell-like structure lacking alpha-helices or beta-sheets where individual lobes contain three subdomains. At least one of these three subdomains in each homologous lobe possesses a sugar-binding pocket that gives RTB its functional character.
Many plants such as [[barley]] have the A chain but not the B chain. People do not get sick from eating large amounts of such products, as ricin A is of extremely low toxicity as long as the B chain is not present.
===Entry into the Cytosol===
The ability of ricin to enter the [[cytosol]] depends on hydrogen bonding interactions between RTB amino acid residues and complex carbohydrates on the surface of eukaryotic cells containing either terminal N-acetyl galactosamine or beta-1,4-linked galactose residues. Additionally, the mannose-type glycans of ricin are able to bind cells that express mannose receptors.<ref>{{cite journal | author=Magnusson AS, Kjeken R, Berg T | title=Characterization of two distinct pathways of endocytosis of ricin by rat liver endothelial cells | journal=Exp Cell Res | year=1993 | volume=205 | pages=118–25 | doi=10.1006/excr.1993.1065}}</ref> Experimentally, RTB has been shown to bind to the cell surface on the order of 10<sup>6</sup>-10<sup>8</sup> ricin molecules per cell surface.<ref>{{cite journal | author=Sphyris N, Lord JM, Wales R, et al. | title=Mutational analysis of the ricinus lectin b-chains: Galactose-binding ability of the gamma subdomain of ricinus communis agglutin b-chain | journal=J Biol Chem | year=1995 | volume=270 | pages=20292–97 | doi=10.1074/jbc.270.35.20292 | pmid=7657599}}</ref>
The profuse binding of ricin to surface membranes allows internalization with all types of membrane invaginations. Experimental evidence points to ricin uptake in both clathrin-coated pits, as well as clathrin-independent pathways including caveolae and macropinocytosis.<ref>{{cite journal | author=Moya M, Dautry-Varsat A, Goud B, et al. | title=Inhibition of coated pit formatin in Hep2 cells blocks the cytotoxicity of diptheria toxin but not that of ricin toxin | journal=J Cell Biol | year=1985 | volume=101 | pages=548–59 | doi=10.1083/jcb.101.2.548 | pmid=2862151}}</ref><ref>{{cite journal | author=Nichols, BJ, Lippincott-Schwartz J | title=Endocytosis without clathrin coats | journal=Trends Cell Biol | year=2001 | volume=11 | pages=406–12 | doi=10.1016/S0962-8924(01)02107-9}}</ref> Vesicles shuttle ricin to endosomes that are delivered to the Golgi apparatus. The active acidification of endosomes are thought to have little effect on the functional properties of ricin. Because ricin is stable over a wide pH range, degradation in endosomes or lysosomes offer little or no protection against ricin.<ref>{{cite journal | author=Lord MJ, Jolliffe NA, Marsden CJ, et al. | title=Ricin Mechanisms of Cytotoxicity | journal=Toxicol Rev | year=2003 | volume=22 | issue=1 | pages=53–64 | doi=10.2165/00139709-200322010-00006}}</ref> Ricin molecules are thought to follow retrograde transport through the Golgi and enter the endoplasmic reticulum (ER).
For ricin to function cytotoxically, RTA must be reductively cleaved from RTB in order to release a steric block of the RTA active site. Currently, it is unknown whether this takes place in the ER or in the cytosol. It is speculated that within the ER, RTA utilizes the endoplasmic reticulum-associated protein degradation (ERAD) pathway that exists to eject misfolded proteins to the cytosol.<ref>{{cite journal | author=Roberts LM, Smith DC | title=Ricin: the endoplasmic reticulum connection | journal=Toxicon | year=2004 | volume=44 | pages=469–72 | doi=10.1016/j.toxicon.2004.07.002}}</ref> Chaperones participating in ERAD may recognize RTA as misfolded native protein and translocate it into the cytosol. Additionally, RTA resists degradation by ubiquitination that often occurs with misfolded proteins by maintaining a low content of lysine residues, the usual attachment sites for ubiquitin.<ref>{{cite journal | author=Deeks ED, Cook JP, Day PJ, et al. | title=The low lysine content of ricin A chain reduces the risk of proteolytic degradation after translocation from the endoplasmic reticulum to the cytosol | journal=Biochemistry | year=2002 | volume=41 | pages=3405–13 | doi=10.1021/bi011580v}}</ref> In the cytosol, RTA is free to exert its toxicity on [[ribosome]]s.
===Ribosome Inactivation===
Study of the N-glycosidase activity of ricin was pioneered by Endo and Tsurugi<ref>{{cite journal | author=Endo Y, Tsurugi K | title=RNA N-glycosidase activity of ricin A-chain: mechanism of action of the toxic lectin ricin on eukaryotic ribosomes | journal=J Biol Chem | year=1987 | volume=262 | pages=8128–30}}</ref> who showed that RTA cleaves a glycosidic bond within the large rRNA of the 60S subunit of eukaryotic ribosomes. They subsequently showed RTA specifically and irreversibly hydrolyses the N-glycosidic bond of the adenine residue at position 4324 (A4324) within the 28S rRNA, but leaves the phosphodiester backbone of the RNA intact.<ref>{{cite journal | author=Endo Y, Tsurugi K | title=The RNA N-glycosidase activity of ricin A chain | journal=J Biol Chem | year=1998 | volume=263 | pages=8735–9}}</ref> The ricin targets A4324 that is contained in a highly conserved sequence of 12 nucleotides universally found in eukaryotic ribosomes. The sequence, 5’-AGUACGAGAGGA-3’, termed the sarcin-ricin loop, is important in binding elongation factors during protein synthesis.<ref>{{ cite journal | author=Sperti S, Montanaro L, Mattioli A, et al. | journal=Biochem J | year=1973 | volume=136 | pages=813–5
| unused_data = |Inhibition by ricin of protein synthesis in vitro: 60S ribosomal subunit as the target of the toxin}}</ref> The depurination event rapidly and completely inactivates the ribosome, resulting in toxicity from inhibited protein synthesis. A single RTA molecule in the cytosol is capable of depurinating approximately 1500 ribosomes per minute.
===Depurination Reaction===
Within the active site of RTA, there exist several invariant amino acid residues involved in the depurination of ribosomal RNA.<ref>{{cite journal | author=Lord MJ, Jolliffe NA, Marsden CJ, et al. | title=Ricin Mechanisms of Cytotoxicity | journal=Toxicol Rev | year=2003 | volume=22 | issue=1 | pages=53–64 | doi=10.2165/00139709-200322010-00006}}</ref> Although the exact mechanism of the event is unknown, key amino acid residues identified include tyrosine at positions 80 and 123, glutamic acid at position 177, and arginine at position 180. In particular, Arg180 and Glu177 have been shown to be involved in the catalytic mechanism, and not substrate binding, with enzyme kinetic studies involving RTA mutants. The model proposed by Mozingo and Robertus<ref>{{ cite journal | author=Monzingo AF, Robertus JD | title=X-ray analysis of substrate analogs in the ricin A-chain active site | journal=J Mol Biol | year=1992 | volume=244 | pages=410–22 | doi=10.1006/jmbi.1994.1739}}</ref>, based x-ray structures, is as follows:
<ol>
<li>Sarcin-ricin loop substrate binds RTA active site with target adenine stacking against tyr80 and tyr123.
<li>Arg180 is positioned such that it can protonate N-3 of adenine and break the bond between N-9 of the adenine ring and C-1’ of the ribose.
<li>Bond cleavage results in an oxycarbonium ion on the ribose, stabilized by Glu177.
<li>N-3 protonation of adenine by Arg180 allows deprotonation of a nearby water molecule.
<li>Resulting hydroxyl attacks ribose carbonium ion.
<li>Depurination of adenine results in a neutral ribose on an intact phosphodiester RNA backbone.
</ol>
==Manufacture==
Ricin is easily [[purification|purified]] from [[Castor oil|castor-oil]] manufacturing [[waste]]. The [[seed]] pulp left over from pressing for castor oil contains on average about 5% by weight of ricin.
===Patented extraction process===
The process for extracting ricin is well-known, and for example described in a [[patent]].<ref>"Preparation of Toxic Ricin", {{US patent|3060165}}, assigned to the [[U.S. Secretary of the Army]], inventors: Harry L. Craig, O.H. Alderks, Alsoph H. Corwin, Sally H. Dieke, and Charlotte Karel (granted [[October 23]], [[1962]])</ref> The described extraction method is very similar to the preparation of [[soy protein isolate]]s.
The patent was removed from the [[United States Patent and Trademark Office]] (USPTO) database sometime in 2004, but is still available online through international patent databases.<ref name="http://v3.espacenet.com/origdoc?DB=EPODOC&IDX=US3060165&QPN=US3060165">[http://v3.espacenet.com/origdoc?DB=EPODOC&IDX=US3060165&QPN=US3060165 Harry L. Craig, O.H. Alderks, Alsoph H. Corwin, Sally H. Dieke, and Charlotte Karel, US Patent 3,060,165, "Preparation of Toxic Ricin", granted [[October 23]], 1962]</ref><ref>[http://cryptome.org/ricin-patent.htm]</ref> Modern theories of protein chemistry cast doubt on the effectiveness of the methods disclosed in the patent.<ref name="http://www.globalsecurity.org/org/nsn/nsn-040723.htm">[http://www.globalsecurity.org/org/nsn/nsn-040723.htm http://www.globalsecurity.org/org/nsn/nsn-040723.htm]</ref>
==Potential medicinal use==
Ricins may have therapeutic use in the treatment of [[cancer]], as a so-called "magic bullet" to specifically target and destroy cancer cells:<ref>{{cite journal |author=Lord MJ, Jolliffe NA, Marsden CJ, ''et al'' |title=Ricin. Mechanisms of cytotoxicity |journal=Toxicological reviews |volume=22 |issue=1 |pages=53–64 |year=2003 |pmid=14579547 |doi=}}</ref> Ricin could be linked to a [[monoclonal antibody]] to target malignant cells recognized by the antibody. Modification of ricin is believed to be possible to lessen its toxicity to humans, but not to the cancer cells. A promising approach is also to use the non-toxic B subunit as a vehicle for delivering [[antigen]]s into cells thus greatly increasing their [[immunogenicity]]. Use of ricin as an [[adjuvant]] has potential implications for developing mucosal [[vaccine]]s.
==Use as a chemical/biological warfare agent==
The [[United States]] investigated ricin for its military potential during the [[First World War]]. At that time it was being considered for use either as a toxic dust or as a coating for [[bullet]]s and [[shrapnel]]. The [[dust cloud]] concept could not be adequately developed, and the coated bullet/shrapnel concept would violate the [[Hague Conventions (1899 and 1907)|Hague Convention of 1899]]. The war ended before it was weaponized.
During the [[Second World War]] the United States and [[Canada]] undertook studying ricin in [[cluster bomb]]s. Though there were plans for [[mass production]] and several [[field trial]]s with different [[bomblet]] concepts, the end conclusion was that it was no more economical than using [[phosgene]]. This conclusion was based on comparison of the final weapons rather than ricin's toxicity ([[LD50|LCt<sub>50</sub>]] ~40 mg•min/m<sup>3</sup>). Ricin was given the military symbol W or later WA. Interest in it continued for a short period after the Second World War, but soon subsided when the [[U.S. Army Chemical Corps]] began a program to weaponize [[sarin]].
The [[Soviet Union]] also had ricin. There were speculations that KGB even used it outside of the Soviet bloc, however this was never proven. In 1978, the [[Bulgaria]]n dissident [[Georgi Markov]] was assassinated by Bulgarian [[secret police]] who surreptitiously 'shot' him on a [[London]] street with a modified [[umbrella]] using [[compressed gas]] to fire a tiny pellet contaminated with ricin into his leg.<ref>{{cite web |url=http://www.cnn.com/2003/WORLD/europe/01/07/terror.poison.bulgarian/ |title=Ricin and the umbrella murder |accessdate=2008-03-15 |format= |work= }}</ref> He died in a hospital a few days later; his body was passed to a special poison branch of the [[British MOD|British Ministry of Defence (MOD)]] that discovered the pellet during an [[autopsy]]. The prime suspects were the Bulgarian secret police: Georgi Markov had [[defection|defected]] from Bulgaria some years previously and had subsequently written books and made radio broadcasts which were highly critical of the Bulgarian [[communist]] regime. However, it was believed at the time that Bulgaria would not have been able to produce the poison, and it was also believed that the KGB had supplied it. The KGB denied any involvement although high-profile KGB defectors [[Oleg Kalugin]] and [[Oleg Gordievsky]] have since confirmed the KGB's involvement. Earlier, Soviet [[dissident]] [[Aleksandr Solzhenitsyn]] also suffered (but survived) ricin-like symptoms after a 1971 encounter with KGB agents.<ref>D.M. Thomas, ''Alexander Solzhenitsyn: A Century in His Life,'' 368-378</ref>
Despite ricin's extreme [[toxicity]] and utility as an agent of chemical/biological warfare, it is extremely difficult to limit the production of the toxin. Under both the 1972 [[Biological Weapons Convention]] and the 1997 [[Chemical Weapons Convention]], ricin is listed as a [[List of Schedule 1 substances (CWC)|schedule 1 controlled substance]]. Despite this, more than 1 million [[metric ton]]nes of castor beans are processed each year, and approximately 5% of the total is rendered into a [[toxic waste|waste]] containing high concentrations of ricin toxin.<ref name="http://www.ansci.cornell.edu/plants/toxicagents/ricin/ricin.html">[http://www.ansci.cornell.edu/plants/toxicagents/ricin/ricin.html http://www.ansci.cornell.edu/plants/toxicagents/ricin/ricin.html]</ref>
To put ricin used as a [[weapon]] into perspective, it is worth noting that as a [[biological weapon]] or [[chemical weapon]], ricin may not be considered very powerful in comparison with other agents such as [[botulinum]] or [[anthrax]]. Hence, a military willing to use biological weapons ''and'' having advanced resources would rather use either of the latter instead. Ricin is easy to produce, but is not as practical nor likely to cause as many casualties as other agents. Ricin is inactivated (ie, the [[protein]] changes structure and becomes less dangerous) much more readily than anthrax [[spore]]s, which may remain lethal for decades. (Jan van Aken, an expert on biological weapons explained in an interview with the [[German language|German]] magazine [[Der Spiegel]] that he judges it rather reassuring that [[Al Qaeda]] experimented with ricin as it suggests their inability to produce botulin or anthrax.)
The major reason it is dangerous is that there is no specific [[antidote]], and that it is very easy to obtain (the castor bean plant is a common [[ornamental plant|ornamental]], and can be grown at home without any special care). There have been several reported incidents where ricin has been involved with infanticide where small children have been tricked into eating castor beans because of their striking resemblance to chocolate covered coffee beans. Ricin is actually several [[orders of magnitude]] less toxic than [[botulinum]] or [[Tetanospasmin|tetanus toxin]], but those are more difficult to obtain.
==Detected ricin incidents==
===1978 assassination of Georgi Markov===
On [[7 September]] [[1978]] the [[Bulgarian]] [[dissident]] [[Georgi Markov]] was stabbed in the leg in public on [[Waterloo Bridge]] in the middle of [[London]] by a man using a weapon built into an [[umbrella]]. The weapon embedded a small pellet in Markov's leg which contained ricin. Markov died four days later.{{Fact|date=March 2008}}
[[Image:Ricin plot Daily Mirror.jpg|right|frame|''[[Daily Mirror]]'' front page, part of a media frenzy in the [[United Kingdom]] when the ricin plot news was released.]]
===2003 arrests in Britain===
{{main|Wood Green ricin plot}}
On [[5 January]], [[2003]] the [[Metropolitan Police]] raided a flat in north [[London]] and arrested six [[Algerian]] men whom they claimed were manufacturing ricin as part of a plot for a poison attack on the [[London Underground]]. No ricin was recovered as a result of this raid.
===2003 envelope in South Carolina===
In 2003, a package and letter sealed in a "ricin-contaminated" envelope was intercepted in [[Greenville, South Carolina]], at a [[United States Postal Service]] processing center.<ref>[http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5246a5.htm Investigation of a Ricin-Containing Envelope at a Postal Facility - South Carolina, 2003<!-- Bot generated title -->]</ref>
===2003 White House mail===
Ricin was detected in the [[mail]] at the [[White House]] in [[Washington, D.C.]] in November 2003. The letter containing it was intercepted at a mail handling facility off the grounds of the White House, and it never reached its intended destination. The letter contained a fine powdery substance that later tested positive for ricin. Investigators said it was low [[potency]] and was not considered a health risk. This information was not made public until [[February 3]], [[2004]], when preliminary tests showed the presence of ricin in an office mailroom of [[U.S. Senate Majority Leader]] [[Bill Frist]]'s office. There were no signs that anyone who was near the contaminated area developed any medical problems. Several Senate office buildings were closed as a precaution.
===2006 home in Richmond, Virginia===
In January 2006, ricin was found in a home in [[suburban]] [[Richmond, Virginia]] in the form of mashed castor beans. Although the suspect, [[Chetanand Sewraz]], was allegedly isolating the toxin to kill his estranged wife, and not for some form of [[bioterrorism]], it nonetheless highlighted the ease with which ricin toxin can be made.<ref name="http://wtvr.com/Global/story.asp?S=4457615">[http://wtvr.com/Global/story.asp?S=4457615 http://wtvr.com/Global/story.asp?S=4457615]</ref><ref name="http://wtvr.com/Global/story.asp?S=4457626">[http://wtvr.com/Global/story.asp?S=4457626 http://wtvr.com/Global/story.asp?S=4457626]</ref>
===2008 hotel room in Las Vegas, Nevada===
In February 2008, a man who stayed in a [[Las Vegas, Nevada]] motel room where ricin was found was taken to hospital in critical condition. The man, Roger Von Bergendorff, was hospitalized on [[February 14]]; however, the ricin was not found until [[February 27]] when a relative retrieved his luggage because the motel had not been paid for two weeks. [[Firearm]]s and an "[[Anarchist Cookbook|anarchist type textbook]]" were found in the same motel room where several vials of ricin were found, police reported. According to [[KLAS-TV|Las Vegas 8 Television news]], police noted the ricin section of the textbook was highlighted. <ref>[http://www.cnn.com/2008/US/02/29/ricin.hotel/index.html Police: Man in critical condition after exposure to ricin - CNN.com<!-- Bot generated title -->]</ref><ref>http://news.yahoo.com/s/ap/20080229/ap_on_re_us/motel_hazardous_material;_ylt=AtfdNqvbxuM_cNBPbBipVYCs0NUE</ref> On March 3rd, [[Federal Bureau of Investigation|FBI]] agents searched a Riverton, [[Utah]] house and several storage lockers in West Jordan, Utah linked to Bergendorff, but did not find any traces of ricin.<ref>[http://edition.cnn.com/2008/US/03/02/motel.ricin.ap/index.html FBI searches home, storage units after ricin find - CNN.com<!-- Bot generated title -->]</ref><ref>[http://origin.sltrib.com/ci_8428616 Riverton residents return to homes, but search for deadly toxin continues - Salt Lake Tribune<!-- Bot generated title -->]</ref><ref>[http://www.fox5vegas.com/news/15597214/detail.html Man Wakes From Ricin Coma - Local News Story - KVVU Las Vegas<!-- Bot generated title -->]</ref>
Bergdendorff awoke from a comatose condition on March 14th. He was questioned by police as to why he had such a large quantity of ricin.<ref>[http://www.fox5vegas.com/news/15597214/detail.html Man Wakes From Ricin Coma - Local News Story - KVVU Las Vegas<!-- Bot generated title -->]</ref> Subsequently, he was arrested on April 16 and charged with possession of a biological toxin and two weapons offenses. <ref>[http://news.yahoo.com/s/ap/20080416/ap_on_re_us/ricin_mystery Man at center of Las Vegas ricin case arrested, charged]</ref>
==See also==
* [[2001 anthrax attacks]]
==References==
{{reflist}}
==External links==
* [http://www.hort.purdue.edu/newcrop/afcm/castor.html Castor bean information] at [[Purdue University]]
* [http://www.phls.co.uk/topics_az/deliberate_release/pdf/ricin_guidelines.pdf ricin information] at [[Department of Health (United Kingdom)]]
* [http://www.ansci.cornell.edu/plants/toxicagents/ricin/ricin.html ricin information] at [[Cornell University]]
* [http://news.bbc.co.uk/2/hi/health/2837763.stm Medical research on ricin] at [[BBC]]
* [http://www.wood.army.mil/chmdsd/Army_Chemical_Review/pdfs/2004%20Apr/Kirby-Ricin-04-1.pdf Chemical Review] at [[United States Army]]
* [http://www.bt.cdc.gov/agent/ricin/ Ricin - Emergency Preparations] at [[Centers for Disease Control and Prevention|CDC]]
{{Lectins}}
{{Albumins}}
{{DEFAULTSORT:Ricin}}
[[Category:Biological weapons]]
[[Category:Chemical weapons]]
[[Category:Proteins]]
[[Category:Plant toxins]]
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[[ta:ரைசின்]]
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