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Ricin

Castor beans

The protein ricin (pronounced rye-sin) is a poison manufactured from the castor bean (Ricinus communis). Its name comes from the seed's resemblance to the tick. Ricin can be extracted from castor beans and is known to have an average lethal dose in humans of 0.2 milligrams (1/5,000th of a gram), though some sources give higher figures [1]. It is considered to be twice as deadly as cobra venom.

Toxicity and manufacture

Ricin is poisonous if inhaled, injected, or ingested, acting as a toxin by the inhibition of protein synthesis. There is no known antidote; only symptomatic and supportive treatment is available. Long term organ damage is likely in survivors. In small doses, such as the typical dose contained in a measure of castor oil, ricin causes digestive tract cramps. Ingested in larger doses, ricin causes severe diarrhea and victims can die of shock. (See abrin).

Although the castor bean plant has long been noted for its toxicity, ricin was first isolated and named in 1888 by Hermann Stillmark. Modern feed-making techniques break down the ricin in castor beans by heating at 140 degrees Celsius for 20 minutes, although some studies suggest that residual toxic effects may linger. Although one seed contains enough ricin to kill an adult human, they may pass harmlessly through the digestive system if swallowed whole. [2]. Typically 2.5–20 raw seeds can kill an adult human; 4 a rabbit, 5 a sheep, 6 an ox, 6 a horse, 7 a pig, 11 a dog, but 80 for cocks and ducks.[3]

Ricin consists of two distinct protein chains (almost 30kDa each) that are linked to each other by disulfide bond:

  • Ricin A is toxic to the cell by interfering with Ribosomes, responsible for protein synthesis
  • Ricin B is important in assisting ricin A's entry into a cell by binding with a cell surface component.

Many plants such as barley have the A chain but not the B chain. Since people do not get sick from eating large amounts of such products, ricin A is of extremely low toxicity if and only if the B chain is not present.

Ricin is easily purified from castor-oil manufacturing waste. The seed-pulp left over from pressing for castor oil contains on average about 5% by weight of ricin. Since 0.2 mg of purified Ricin constitutes a fatal dose, this is a considerable amount of ricin.

As little as one castor bean, about 0.5 grams, may be fatal in a child.

In the United states, a person caught manufacturing or possessing ricin may be sentenced up to 30 years in prison.

Potential medicinal use

Ricin may have therapeutic use in the treatment of cancer. Ricin could be linked to a monoclonal antibody to target malignant cells recognized by the antibody. Genetic 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 antigens into cells thus greatly increasing their immunogenicity. Use of ricin as an adjuvant has potential implications for developing mucosal vaccines

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 coated bullets and shrapnel. The dust cloud concept could not be adequately developed, and researchers believed the coated bullet/shrapnel concept was unethical. The War ended before it was weaponized.

During the Second World War the United States and Canada undertook studying ricin in cluster bombs. Though there were plans for mass production and several field trials 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 <30 mg.min.m–3). Ricin was given the military symbol W.

The best-known documented use of ricin as an agent of biological warfare was by the Soviet Union's KGB during the Cold War. In 1978, the Bulgarian 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. He died in hospital a few days later; the pellet was discovered by chance during an autopsy and the poison linked back to the KGB. Earlier, Soviet dissident Aleksandr Solzhenitsyn also suffered (but survived) ricin-like symptoms after a 1971 encounter with KGB agents (D.M. Thomas, Alexander Solzhenitsyn: A Century in His Life, 368-378).

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 schedule 1 controlled substance. Despite this, more than 1 million metric tonnes of castor beans are processed each year, and approximately 5% of the total is rendered into a waste containing high concentrations of ricin toxin [4].

In August of 2002, US officials asserted that the Islamic militant group Ansar al-Islam tested ricin, along with other chemical and biological agents, in northern Iraq.

To put ricin used as weapon into perspective, it is worth noting that as a biological weapon or chemical weapon, ricin may be considered as not very powerful, if only in comparison with other poisons 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 high casualities as other agents. Ricin denatures (ie, the protein changes structure and becomes less dangerous) much more readily than anthrax spores, which may remain lethal for decades. (Jan van Aken, an expert on biological weapons explained in an interview with the 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.)

Pure ricin could be dispersed through the air, however it would tend to be oxidized and rendered harmless by ozone, nitrogen oxides, and other pollutants in a matter of hours. Since it acts as an enzyme, catalyzing destruction of ribosomes, even a single oxidation is likely to render the ricin molecule harmless. Presumably it could be sealed inside some sort of dust particle that would dissolve in water, but this would be difficult.

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, and can be grown at home without any special care). Ricin is actually several orders of magnitude less toxic than botulinum or tetanus toxins, but those are more difficult to obtain.

Ricin patent

"Preparation of Toxic Ricin",
patent application.

The process for creating ricin is well-known, in part because a patent was granted for it in 1952. The inventors named in US Patent 3,060,165 (granted October 23, 1962) "Preparation of Toxic Ricin", assigned to the U.S. Secretary of the Army, are Harry L. Craig, O.H. Alderks, Alsoph H. Corwin, Sally H. Dieke, and Charlotte Karel.

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.

Ricin extraction process

The extraction of ricin from castor beans is very similar to the prepartion of soy protein isolates. Modern extraction plants might use membrane filtration to make highly purified ricin isolates

Ricin is initially extracted from defatted castor beans by aquous extraction at pH 3.8 to yield a leachate containing solubilized ricin. The leachate is filtered to remove insoluble matter and the crude ricin then precipitated by the addition of a 12% solution of sodium sulfate with a pH of 7.0-8.0. After precipitation, the crude ricin cake is washed with a 16.7% solution of sodium sulfate to remove extranious nitrogenous substances. The precipitated ricin may be reextracted once to further purify it.

The final ricin precipitate is dried and then purified by floatation in carbon tetrachloride. An aerosol powder may be prepared by spray drying or air grinding the purified ricin using cold air.

Ricin-related arrests in Britain in 2003

It was widely reported in the media that traces of ricin were detected by British police in a flat in Wood Green, North London after a raid on a suspected ring of terrorists on 5 January 2003. Media reports stated that a group was suspected of intending to use the poison in an attack on the London Underground. However at the trial of Kamel Bourgass in 2005 it became apparent that within a few days of the raid the leader of the Biological Weapon Identification Group at the Porton Down Defence Science and Technology Laboratory had concluded that ricin was not present at Wood Green [5] [6]. Some acetone, 22 castor beans, and poor recipes for ricin and other poisons copied from the Internet were found. It appears that an individual conducting amateur research on poisons was found in this raid.

A little later several arrests were made in France and a bottle of something that tested positive for ricin was found. Further analysis identified the material as ground wheat germ. The analytic confusion was caused by the similarity of many plant proteins to one of the ricin components, which suggests that higher quality (better specificity and sensitivity) analytic tests for ricin are needed.

Six more suspects were arrested in Bournemouth in England in connection with the investigation into the alleged ricin incident in London. They were not convicted of any poisons related crime.

Three more suspects were arrested in Manchester in England in connection with the investigation of the alleged ricin found in London, following a raid carried out pursuant to an investigation into immigration issues. A Special Branch policeman, DC Stephen Oake, was fatally stabbed during the arrests, and three other officers were also injured, one seriously.

On January 20, 2003 Finsbury Park mosque was raided by police, apparently as part of the investigation into the alleged discovery of ricin in Wood Green. A number of men who were apparently living at the mosque were arrested.

On February 5, 2003, U.S. Secretary of State Colin Powell presented those arrested as the "UK Poison Cell" of a global terrorist network in making the case for military intervention in Iraq to the UN Security Council [7].

In April 2005 31-year-old Kamel Bourgass was jailed for 17 years after being convicted of conspiracy to commit a public nuisance "by the use of poisons and explosives to cause disruption, fear or injury". He was also jailed for life following a conviction for murdering the Special Branch policeman who went to arrest him. All others accused in connection with the Wood Green flat were acquitted on all counts.

Ricin in Washington, D.C.

Ricin was detected in the mail at the White House in Washington, D.C. in November of 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.

Ricin in popular culture

Ricin was the poison used in the Agatha Christie Tommy and Tuppence whodunnit The House of Lurking Death in a 1929 collection of short stories called Partners in Crime.

Ricin was used as the poison of choice of the murderer in the 1962 comedy film Kill or Cure.

Ricin was mentioned in the "call me the prankster" comic at toothpaste for dinner

The Penn and Teller book How To Play With Your Food (ISBN 0679743111) includes a "gimmicks envelope" of small objects related to the tricks inside the book. One of these is a sticker reading "With all-natural ricin!". The book explains that ricin is a poison.


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The book explains that ricin is a poison. [5]. One of these is a sticker reading "With all-natural ricin!". The smaller number of copies of this version in circulation meant that Microsoft's servers suffered few ill effects. The Penn and Teller book How To Play With Your Food (ISBN 0679743111) includes a "gimmicks envelope" of small objects related to the tricks inside the book. A second version, Mydoom.B, as well as carrying the original payloads, also targets the Microsoft website and blocks HTTP access to Microsoft sites and popular online antivirus sites, thus blocking virus removal tools or updates to antivirus software. Ricin was mentioned in the "call me the prankster" comic at toothpaste for dinner. The original version, Mydoom.A, is described as carrying two payloads:.

Ricin was used as the poison of choice of the murderer in the 1962 comedy film Kill or Cure. Some early reports claimed the worm avoids all .edu addresses, but this is not the case. Ricin was the poison used in the Agatha Christie Tommy and Tuppence whodunnit The House of Lurking Death in a 1929 collection of short stories called Partners in Crime. Mydoom avoids targeting e-mail addresses at certain universities, such as Rutgers, MIT, Stanford and UC Berkeley, as well as certain companies such as Microsoft and Symantec. Several Senate office buildings were closed as a precaution. It also copies itself to the "shared folder" of peer-to-peer file-sharing application KaZaA in an attempt to spread that way. There were no signs that anyone who was near the contaminated area developed any medical problems. The mail contains an attachment that, if executed, resends the worm to email addresses found in local files such as a user's address book.

Senate Majority Leader Bill Frist's office. Mydoom is primarily transmitted via e-mail, appearing as a transmission error, with subject lines including "Error," "Mail Delivery System," "Test" or "Mail Transaction Failed" in different languages, including English and French. 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. . Investigators said it was low potency and was not considered a health risk. I thought having 'doom' in the name would be appropriate." [4]. The letter contained a fine powdery substance that later tested positive for ricin. He noted: "It was evident early on that this would be very big.

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. Schmugar chose the name after noticing the text "mydom" within a line of the program's code. in November of 2003. Mydoom was named by Craig Schmugar, an employee of computer security firm McAfee and one of the earliest discoverers of the worm. Ricin was detected in the mail at the White House in Washington, D.C. Later analyses were less conclusive as to the link between the two worms. All others accused in connection with the Wood Green flat were acquitted on all counts. Initial analyses of Mydoom suggested that it was a variant of the Mimail worm — hence the alternate name Mimail.R — prompting speculation that the same persons were responsible for both worms.

He was also jailed for life following a conviction for murdering the Special Branch policeman who went to arrest him. [3]. In April 2005 31-year-old Kamel Bourgass was jailed for 17 years after being convicted of conspiracy to commit a public nuisance "by the use of poisons and explosives to cause disruption, fear or injury". Since then, it has been likewise rejected by law enforcement agents investigating the virus, who attribute it to organized online crime gangs. Secretary of State Colin Powell presented those arrested as the "UK Poison Cell" of a global terrorist network in making the case for military intervention in Iraq to the UN Security Council [7]. This theory was rejected out of hand by security researchers. On February 5, 2003, U.S. Trade press conjecture, spurred on by SCO Group's own claims, held that this meant the worm was created by a Linux or open source supporter in retaliation for SCO Group's controversial legal actions and public statements against Linux.

A number of men who were apparently living at the mosque were arrested. 25% of Mydoom.A-infected hosts targeted www.sco.com with a flood of traffic. On January 20, 2003 Finsbury Park mosque was raided by police, apparently as part of the investigation into the alleged discovery of ricin in Wood Green. Speculative early coverage held that the sole purpose of the worm was to perpetrate a distributed denial-of-service attack against SCO Group. A Special Branch policeman, DC Stephen Oake, was fatally stabbed during the arrests, and three other officers were also injured, one seriously. [2] The actual author of the worm is unknown. Three more suspects were arrested in Manchester in England in connection with the investigation of the alleged ricin found in London, following a raid carried out pursuant to an investigation into immigration issues. Early on, several security firms published their belief that the worm originated from a professional underground programmer in Russia.

They were not convicted of any poisons related crime. Mydoom appears to have been commissioned by e-mail spammers so as to send junk e-mail through infected computers.[1] The worm contains the text message "andy; I'm just doing my job, nothing personal, sorry," leading many to believe that the worm's creator was paid to create it. Six more suspects were arrested in Bournemouth in England in connection with the investigation into the alleged ricin incident in London. It became the fastest spreading email worm ever (as of January 2004), exceeding previous records set by the Sobig worm. The analytic confusion was caused by the similarity of many plant proteins to one of the ricin components, which suggests that higher quality (better specificity and sensitivity) analytic tests for ricin are needed. It was first sighted on January 26, 2004. Further analysis identified the material as ground wheat germ. Mydoom, also known as Novarg, Mimail.R and Shimgapi, is a computer worm affecting Microsoft Windows.

A little later several arrests were made in France and a bottle of something that tested positive for ricin was found. 18 February 2005: MyDoom version AO appears. It appears that an individual conducting amateur research on poisons was found in this raid. 10 September: MyDoom versions U, V, W and X appear, sparking worries that a new, more powerful MyDoom is being prepared. Some acetone, 22 castor beans, and poor recipes for ricin and other poisons copied from the Internet were found. 26 July: A variant of Mydoom attacks Google, AltaVista and Lycos, completely stopping the function of the popular Google search engine for the larger portion of the workday, and creating noticeable slow-downs in the AltaVista and Lycos engines for hours. However at the trial of Kamel Bourgass in 2005 it became apparent that within a few days of the raid the leader of the Biological Weapon Identification Group at the Porton Down Defence Science and Technology Laboratory had concluded that ricin was not present at Wood Green [5] [6]. 1 March: Mydoom.B is programmed to stop spreading; as with Mydoom.A, the backdoor remains open.

Media reports stated that a group was suspected of intending to use the poison in an attack on the London Underground. However, the backdoor remains open after this date. It was widely reported in the media that traces of ricin were detected by British police in a flat in Wood Green, North London after a raid on a suspected ring of terrorists on 5 January 2003. 12 February: Mydoom.A is programmed to stop spreading. An aerosol powder may be prepared by spray drying or air grinding the purified ricin using cold air. Its payload, akin to one of Mydoom.B's, is a denial-of-service attack against Microsoft. The final ricin precipitate is dried and then purified by floatation in carbon tetrachloride. It does not attack non-infected computers.

The precipitated ricin may be reextracted once to further purify it. [7] This worm uses the backdoor left by Mydoom to spread. After precipitation, the crude ricin cake is washed with a 16.7% solution of sodium sulfate to remove extranious nitrogenous substances. 9 February: Doomjuice, a "parasitic" worm, begins spreading. The leachate is filtered to remove insoluble matter and the crude ricin then precipitated by the addition of a 12% solution of sodium sulfate with a pH of 7.0-8.0. Some experts point out that the burden is less than that of Microsoft software updates and other such web-based services. Ricin is initially extracted from defatted castor beans by aquous extraction at pH 3.8 to yield a leachate containing solubilized ricin. This is attributed to the comparatively low distribution of the Mydoom.B variant, the high load tolerance of Microsoft's web servers and precautions taken by the company.

Modern extraction plants might use membrane filtration to make highly purified ricin isolates. However, the impact of the attack remains minimal and www.microsoft.com remains functional. The extraction of ricin from castor beans is very similar to the prepartion of soy protein isolates. 3 February: Mydoom.B's distributed denial of service attack on Microsoft begins, for which Microsoft prepares by offering a website which will not be affected by the worm, information.microsoft.com. 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. 2 February: The SCO Group moves its site to www.thescogroup.com. Dieke, and Charlotte Karel. (There is as yet no independent confirmation of www.sco.com in fact suffering the planned DDOS.).

Corwin, Sally H. As 1 February arrives in East Asia and Australia, SCO removes www.sco.com from the DNS around 1700 UTC on 31 January. Alderks, Alsoph H. 1 February 2004: An estimated one million computers around the world infected with Mydoom begin the virus's massive distributed denial of service attack—the largest such attack to date. Craig, O.H. Microsoft offers US $250,000 reward for information leading to the arrest of the creator of Mydoom.B. Secretary of the Army, are Harry L. 29 January: The spread of Mydoom begins to decline as bugs in Mydoom.B's code prevent it from spreading as rapidly as first anticipated.

The inventors named in US Patent 3,060,165 (granted October 23, 1962) "Preparation of Toxic Ricin", assigned to the U.S. Mydoom.B also blocks access to the websites of over 60 computer security companies, as well as pop-up advertisements provided by DoubleClick and other online marketing companies. The process for creating ricin is well-known, in part because a patent was granted for it in 1952. The new version includes the original denial of service attack against SCO Group and an identical attack aimed at Microsoft.com beginning on 3 February 2004 — though both attacks are suspected to be either broken, or non-functional decoy code intended to conceal the backdoor function of Mydoom. Ricin is actually several orders of magnitude less toxic than botulinum or tetanus toxins, but those are more difficult to obtain. The first messages sent by Mydoom.B are identified at around 1400 UTC and also appear to originate from Russia. 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, and can be grown at home without any special care). 28 January: A second version of the worm is discovered two days after the initial attack.

Presumably it could be sealed inside some sort of dust particle that would dissolve in water, but this would be difficult. In the US, the FBI and the Secret Service begin investigations into the worm. Since it acts as an enzyme, catalyzing destruction of ribosomes, even a single oxidation is likely to render the ricin molecule harmless. 27 January: SCO Group offers a US $250,000 reward for information leading to the arrest of the worm's creator. Pure ricin could be dispersed through the air, however it would tend to be oxidized and rendered harmless by ozone, nitrogen oxides, and other pollutants in a matter of hours. Computer security companies report that Mydoom is responsible for approximately one in ten e-mail messages at this time. (Jan van Aken, an expert on biological weapons explained in an interview with the 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.). For a period of a few hours mid-day, the worm's rapid spread slows overall internet performance by approximately ten percent and average web page load times by approximately fifty percent.

Ricin denatures (ie, the protein changes structure and becomes less dangerous) much more readily than anthrax spores, which may remain lethal for decades. The earliest messages originate from Russia. Ricin is easy to produce, but is not as practical nor likely to cause as high casualities as other agents. 26 January 2004: The Mydoom virus is first identified around 8am EST (1300 UTC), just before the beginning of the workday in North America. Hence, a military willing to use biological weapons and having advanced resources would rather use either of the latter instead. Later testing suggests that it functions in only 25% of infected systems. To put ricin used as weapon into perspective, it is worth noting that as a biological weapon or chemical weapon, ricin may be considered as not very powerful, if only in comparison with other poisons such as botulinum or anthrax. Many virus analysts doubted if this payload would actually function.

In August of 2002, US officials asserted that the Islamic militant group Ansar al-Islam tested ricin, along with other chemical and biological agents, in northern Iraq. A denial of service attack against the website of the controversial company SCO Group, timed to commence 1 February 2004. Despite this, more than 1 million metric tonnes of castor beans are processed each year, and approximately 5% of the total is rendered into a waste containing high concentrations of ricin toxin [4]. A backdoor on port 3127/tcp to allow remote control of the subverted PC (by putting its own SHIMGAPI.DLL file in the system32 directory and launching it as a child process of the Windows Explorer); this is essentially the same backdoor used by Mimail. Under both the 1972 Biological Weapons Convention and the 1997 Chemical Weapons Convention, ricin is listed as a schedule 1 controlled substance. 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.

Thomas, Alexander Solzhenitsyn: A Century in His Life, 368-378). Earlier, Soviet dissident Aleksandr Solzhenitsyn also suffered (but survived) ricin-like symptoms after a 1971 encounter with KGB agents (D.M. He died in hospital a few days later; the pellet was discovered by chance during an autopsy and the poison linked back to the KGB. In 1978, the Bulgarian 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.

The best-known documented use of ricin as an agent of biological warfare was by the Soviet Union's KGB during the Cold War. Ricin was given the military symbol W. This conclusion was based on comparison of the final weapons rather than ricin's toxicity (LD50 <30 mg.min.m–3). Though there were plans for mass production and several field trials with different bomblet concepts, the end conclusion was that it was no more economical than using phosgene.

During the Second World War the United States and Canada undertook studying ricin in cluster bombs. The War ended before it was weaponized. The dust cloud concept could not be adequately developed, and researchers believed the coated bullet/shrapnel concept was unethical. At that time it was being considered for use either as a toxic dust or coated bullets and shrapnel.

The United States investigated ricin for its military potential during the First World War. Use of ricin as an adjuvant has potential implications for developing mucosal vaccines. A promising approach is also to use the non-toxic B subunit as a vehicle for delivering antigens into cells thus greatly increasing their immunogenicity. Genetic modification of ricin is believed to be possible to lessen its toxicity to humans, but not to the cancer cells.

Ricin could be linked to a monoclonal antibody to target malignant cells recognized by the antibody. Ricin may have therapeutic use in the treatment of cancer. In the United states, a person caught manufacturing or possessing ricin may be sentenced up to 30 years in prison. As little as one castor bean, about 0.5 grams, may be fatal in a child.

Since 0.2 mg of purified Ricin constitutes a fatal dose, this is a considerable amount of ricin. The seed-pulp left over from pressing for castor oil contains on average about 5% by weight of ricin. Ricin is easily purified from castor-oil manufacturing waste. Since people do not get sick from eating large amounts of such products, ricin A is of extremely low toxicity if and only if the B chain is not present..

Many plants such as barley have the A chain but not the B chain. Ricin consists of two distinct protein chains (almost 30kDa each) that are linked to each other by disulfide bond:. Typically 2.5–20 raw seeds can kill an adult human; 4 a rabbit, 5 a sheep, 6 an ox, 6 a horse, 7 a pig, 11 a dog, but 80 for cocks and ducks.[3]. [2].

Although one seed contains enough ricin to kill an adult human, they may pass harmlessly through the digestive system if swallowed whole. Modern feed-making techniques break down the ricin in castor beans by heating at 140 degrees Celsius for 20 minutes, although some studies suggest that residual toxic effects may linger. Although the castor bean plant has long been noted for its toxicity, ricin was first isolated and named in 1888 by Hermann Stillmark. (See abrin).

Ingested in larger doses, ricin causes severe diarrhea and victims can die of shock. In small doses, such as the typical dose contained in a measure of castor oil, ricin causes digestive tract cramps. Long term organ damage is likely in survivors. There is no known antidote; only symptomatic and supportive treatment is available.

Ricin is poisonous if inhaled, injected, or ingested, acting as a toxin by the inhibition of protein synthesis. . It is considered to be twice as deadly as cobra venom. Ricin can be extracted from castor beans and is known to have an average lethal dose in humans of 0.2 milligrams (1/5,000th of a gram), though some sources give higher figures [1].

Its name comes from the seed's resemblance to the tick. The protein ricin (pronounced rye-sin) is a poison manufactured from the castor bean (Ricinus communis). Ricin B is important in assisting ricin A's entry into a cell by binding with a cell surface component. Ricin A is toxic to the cell by interfering with Ribosomes, responsible for protein synthesis.

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