Guanidines from plants

Several kits are commercially available for the extraction of RNA from plant, bacteria, or mammalian sources. We have used the RNeasy Mini Kit (Qiagen, Valencia, CA) for the extraction of RNA from bacteria following the procedure recommended by the manufacturer (92). This kit relies on guanidine thiocyanate-silica isolation of RNA. Here, guanidine thiocyanate serves as a chaotropic agent, which both lyses cells and inactivates nucleases. In its presence, the released nucleic acids bind to silica particles, which provide a solid phase from which the collected RNA can later be eluted using water (93). This kit is suitable for the isolation and purification of up to 100 pg RNA molecules >200... 

These four purine alkaloids are much more important as animal than as plant constituents. Together with creatine, methyl guanidine acetic acid (p. 441), and creatinine, the anhydride of creatine, they constitute the greater part of what are termed the nitrogenous extractives of muscular tissue. They are present in ordinary beef extract and may be isolated from it. In addition to being present in muscular tissue they are mostly found in the brain, thymus, liver, kidney, spleen and pancreas. Xanthine and hypoxanthine are also present in urine, being the elimination product of caffeine in food. Also associated with... 

C5H 4N4, Mr 130.19, mp. 101.5-103 °C. A. is a guanidine derivative formed by decarboxylation of L- ar-ginine. It is an intermediate in the, in plants especially widely distributed, biosynthesis of putrescine from arginine. Natural sources include ergot, the Asteraceae Ambrosia artemisifolia, the sea anemone Anthopleura japonica and herring semen. 

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