Ricin is a cytotoxic protein that inactivates ribosomes by hydrolyzing the N-glycosidic bond at position A4324 in eukaryotic 28S rRNA. Its substrate domain forms a double helical stem and a 17-base loop that includes the sequence GAGA, the second adenosine of which corresponds to A4324. Recently, studies of mutant RNAs have shown that the four-nucleotide loop, GAGA, can function as a substrate ...

Sampling of small molecules from both porous and non-porous surfaces poses a significant challenge across biological agents. Particle sizes of toxins are smaller than living organisms and can be extremely toxic at low level concentrations. A small number of studies evaluating sampling efficiencies of commercial off the shelf (COTS) materials have been performed with toxins and proteins. However...

Accidental and intended Ricinus communis intoxications in humans and animals have been known for centuries but the causative agent remained elusive until 1888 when Stillmark attributed the toxicity to the lectin ricin. Ricinus communis is grown worldwide on an industrial scale for the production of castor oil. As by-product in castor oil production ricin is mass produced above 1 million tons pe...

An immunotoxin (IT) was prepared from monoclonal antibody (MoAb) 115D8 and ricin A chain. MoAb 115D8 is directed against the carcinoma-associated sialomucin MAM-6. In a protein synthesis inhibition assay this IT was cytotoxic for the human breast cancer cell line T47D. Using postembedding immunoelectron microscopy the binding and intracellular routing of the IT in T47D cells were studied by sim...

Trypsinized BHK cells become attached to glass that has been derivatized with a variety of lectins with well-defined specificity for cell-surface carbohydrates. Provided a threshold concentration of glass-immobilized protein is present the cells undergo a transformation to a well-spread morphology. The matrix density of lectins (ricin and concanavalin A) required to trigger this morphological t...

Abrin, ricin, and cisplatin produced significant increases in survival times of mice inoculated with 10(6) Ehrlich ascites carcinoma or L1210 leukemia cells 24 hours prior to treatment. Combinations of abrin or ricin with cisplatin produced markedly synergistic action in prolonging survival times of mice bearing cell line A of L1210 leukemia. For example, a dosage of 1.33 micrograms per kg abri...

Neocarzinostatin (NCS), styrene-maleic acid copolymer-conjugated neocarzinostatin (SMANCS), and ricin exhibited cytotoxicity against two different types of Chinese hamster ovary cells, parental AUXB1 cells and the multidrug-resistant (MI )K) subline CHRC5 cells at the nanomolar range. These doses were much lower than those of the other anticancer drugs tested (micromolar range), even after a sh...

The oral and intraperitoneal (i.p.) toxicities to female BALB/c mice of ricin and abrin in phosphate-buffered saline (PBS), spring water, apple juice, and half-and-half (only oral) were examined after brief (2 h) and prolonged (11 to 13 days) storage. The ricin and abrin samples prepared in PBS had oral toxicities consistent with those previous studies, indicating oral and i.p. 50% lethal doses...

Neocarzinostatin (NCS), styrene-maleic acid copolymer-conjugated neocarzinostatin (SMANCS), and ricin exhibited cytotoxicity against two different types of Chinese hamster ovary cells, parental AUXB1 cells and the multidrug-resistant (MI )K) subline CHRC5 cells at the nanomolar range. These doses were much lower than those of the other anticancer drugs tested (micromolar range), even after a sh...

The high fluorescence of adenine-containing compounds after reaction with chloroacetaldehyde was used to measure the adenine released from rat liver and Artemia salina ribosomes by the action of ricin A chain and gelonin, two ribosome-inactivating proteins (RIPs) that share the same mechanism of action, consisting in the hydrolysis of the N-glycosidic bond of A-4324 of 28 S rRNA. Two methods we...