Ricin toxin detection

Individual BIDS are combined together into a corps-wide network by a secure communication system. An improved BIDS is being developed with the capability to detect two species of Brucella, Francisella tularensis, and ricin toxin. Detection capabilities for additional agents will no doubt be added to future models.33... 

As for ricin, abrin detection is possible by radioimmunoasay with little cross-reactivity between the two toxins (Godal et al, 1981). 

This prevented investigators from establishing the type of substance that had been used, but it was sufficient to determine that Markov had not died of natural causes. BATS (British Anti-Terrorist Squad), detectives then joined the Scotland Yard investigating team. After weeks of research and experimentation, in January 1979, a Coroner s Inquest in London Gavin Thurston ruled that Georgi Markov had been killed via ricin toxin. Traces of ricin were possibly found later thereupon. 

These advanees in the use of PDA for detection have allowed us to demonstrate the detection of a variety of biologically relevant targets including Escherichia coli E. coli). Bacillus globigii spores (BG), a simulant for B. anthracis and ricin toxin. 

We have investigated using the attached hposomes for detection of ricin toxin and BG spores. This format ahowed us to use assay buffers that would aggregate free liposome solutions, for example, buffers containing high concentrations of Ca. For the detection of ricin, we screened attached liposome... 

Higgins et al. (1999) developed a system for the detection of Staphylococcus enterotoxinB (SEB), ricin toxin. Yersinia pestisYl antigen and 5ac/7/MX anthracis PA antigen based on the principle of electrochemiluminescence (ECL). ECL is a process that involves the generation of light from a voltage-dependent, cyclic oxidation-reduction reaction of rathenium heavy metal chelate. The redox... 

Several biological threat agents were also detected employing ECL approach including purified Staphylococcus aureus enterotoxin B, botulinus A, cholera toxin, and ricin toxins [187]. Another study in the following years focused on Bacillus anthracis and E. coli 0157 H7 and used a male-specific coliphage virus to stimulate the detection of viral agents such as smallpox, Ebola, and yellow fever [186]. This work was later on extended to field samples to measure... 

The ricin toxin has been detected in tissue sections, some tissue specimens, nasal swabs, and fluids by using immunologically based methods to study animals and... 

Ricin is the deadliest plant toxin known. It also has the advantage of being impossible to detect at an autopsy. (Note - Work is currently being done at the University of Leeds in England to develop a means of... 

Antibody-toxin conjugates made with ricin A chain, abrin A chain, gelomn, and momordin can be stored for at least 4 yr at -70°C without detectable loss of activity. The bond between the antibody and the RIP breaks down very slowly at 4°C in PBSE but, provided that care is taken to ensure the sterility of the solution, conjugates can be stored under these conditions for up to one year with little deterioration in quality. 

Detection of staphylococcal enterotoxin B (SEB), a causative agent of food poisoning, was achieved by QDs conjugated with polyclonal sheep anti-SEB antibody.57 Moreover, this approach also harbors the possibility of a multiplexed immunoassay (see Fig. 12.3), which was first reported by Goldman et al.58 in 2004 four toxins of interest in food- or water-borne illnesses (cholera toxin, ricin,... 

A major application of LC/ESI/MS is the characterization and detection of toxins, ranging from relatively small molecules, such as mycotoxins and some marine toxins, to the large proteinaceous toxins such as ricin and botulinum toxins. The marine toxin saxitoxin and the plant toxin ricin are specifically listed in Schedule 1 of the CWC as examples of toxins. A comprehensive review of LC/MS in toxin analysis would require a major chapter in its own right. Hancock and D Agostino 1711 reviewed approaches to the mass spectrometric identification of selected low molecular mass toxins. This chapter will describe examples of LC/MS in the analysis of marine, fungal, bacterial, and plant toxins, which are of possible relevance to the CWC. 

Wannemacher, R.W., Jr., Hewetson, J.F., Lemley, P.V. (1991). Comparison of detection of ricin in castor bean extracts by bioassays, immunoassays, and chemical procedures (abstr 030), 10th World Congress on Animal, Plant, and Microbial Toxins, Singapore. 

Complete elucidation of the mechanisms by which ricin kills target cells remains an area of active study, but it is clear that the A -glycosidase activity of RTA is the essential triggering event. Inhibition of protein synthesis precedes other detectable alterations in target cell biochemistry. Ricin blocks amino acid incorporation in cmde microsome preparations before changes occur in energy metabohsm or oxidative phosphorylation the toxin has essentially no effect on mitochondrial respiration in isolated mitochondria or tumor cells (Waller et al., 1966 Dirheimer et al., 1968 Lin et al., 1971). Likewise, the first observable cytotoxic effect of ricin in cell culture is typically the inhibition of protein synthesis, followed by a reduction in DNA synthesis (Lin et al., 1970 Lin et al., 1971 Onozaki et al., 1972 Refsnes et al., 1974 Nicolson et al., 1975 Olsnes et al., 1976 Refsnes et al., 1977). 

Injection (i.v.) of laboratory rats with I-ricin resulted in an accumulation of about 70% of the toxin in the spleen, liver, and muscle at 30 m, with detectable levels decreasing to about 11 % of injected toxin by 24 h after exposure (Ramsden et al., 1989). Injection (i.m.) of rats with ricin showed concentration of the toxin at the injection site and the ipsilateral para-aortic lymph nodes beginning as early as 4—8 h after exposure (Griffiths et al., 1986). 

Ricin can be detected in the blood or other bodly fluids of exposed animals using competitive radioimmunoassays or enzyme-linked immunosorbent assays (ELISA). These methods generally do not distinguish between active ricin molecules versus partially degraded or otherwise inactivated toxin. The postexposure time limit for accurate antibody-based detection of ricin in biological samples varies and depends on the route of exposure and the absorbed dose. In the laboratory, ELISA detects ricin in oro-nasal swabs of NHP exposed to ricin aerosol up to 24 h after exposure (Franz and Jaax, 1997). Likewise, ELISA detects ricin in selected tissues of laboratory rats up to 48 h after an i.m. challenge (Leith et al., 1988). 

Ricin is a highly immunogenic toxin, and paired acute and convalescent sera should be obtained from survivors for measurement of antibody response. Conceptually, the detection of circulating antiricin antibodies formed in response to sublethal toxin exposure is possible for exposed individuals who survive for 2-3 weeks (Hunt et al., 1918). However, humoral immunoglobin M responses would likely be of short duration, and no immunological memory would be anticipated without boosting. 

In cases where the toxin is metabolized, excreted, or otherwise not available for immunological or chemical detection, it may be possible to verify an exposure to ricin or castor seeds for forensic purposes by detecting other unique components of the R. communis plant. PCR can detect residual castor seed DNA in most ricin preparations. Ricinine, an alkaloid (3-cyano-4-rnethoxy-A -rnethyl-2-pyridone) produced by castor seeds, has been proposed as a biomarker for ricin exposure the detection limit for ricinine by electrospray ionization tandem mass spectrometry is as low as 0.083 ng/mL in urine of exposed subjects (Johnson et al., 2005). 

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