Selective sequestration

Dobler, S., Haberer, W., Witte, L. and Hartmann, T. 2000. Selective sequestration of pyrrolizidine alkaloids from diverse host plants by Longitarsus flea beetles (Coleoptera, Chrysomelidae). Journal of Chemical Ecology, 26 1281-1298. 

Selective Sequestration. Sequestration of plant natural products is an idiosyncratic phenomenon, and there is little indication that the profiles of insect-stored allelochemics in any way mirror those of their plant food sources. In general, each insect species treats Ingested plant allelochemics distinctively, so that a compound excreted in toto by one species may constitute the main sequestration product of another. Unfortunately, while these sequestrative idiosyncrasies are quite evident, their significance is not. 

Solid-supported reagents which have found utility include Nafion-scandium Lewis acid catalyst (allyl additions to aldehydes) [62], HOBt (medium-ring lactamization) [63], EDC (preparation of active esters) [64], and thiazolium hydrotribromide (brominations) [65], A review has also appeared describing the use of supported reagents in separation science, primarily for the selective sequestration of metal ions [66],... 

HARTMANN, T WITTE, L., EHMKE, A., THEURING, C ROWELL-RAHIER, M., PASTEELS, J.M., Selective sequestration and metabolism of plant derived pyrrolizidine alkaloids by chrysomelid leaf beetles. Phytochemistry, 1997, 45, 489-497. 

Liu Z, Nalcatsu K, Brien JF et al (1993) Selective sequestration of nitric oxide by subcellular components of vascukr smooth musde and platelets rdatioiufaip to nitric oxide stimulation of the soluble gusnylyl cydase. Can fHiysiol Pharmacol 71 938 94S. 

The concept of selective sequestration of non-product species was first demonstrated using solid-supported scavengers with electrophilic and nucleophilic character in amine acylation, amine alkylation, and reductive amination protocols [46]. Since then, a wide range of scavenger reagents has become commercially available from various suppliers. The structures and functions of these scavenger resins are shown in Table 1. 

In any case, it is clear that artemisininoids act by an alkylant mechanism and that this mechanism differs from that shown by other alkylant STLs as discussed above. It is highly noteworthy that selective toxicity occurs towards various states in the life-cycle of Plasmodium since heme-associated toxification by the described mechanism should occur also in uninfected cells. This selectivity is likely to be -at least in part- due to selective sequestration in infected erythrocytes as mentioned above. Evidence has been presented that -apart from targeting malaria-specific proteins- processes consuming metabolic energy, i.e. active transport, is involved in this selective uptake [92] but the transport mechanism is not known in detail. 

Radiocesium is a significant issue as a part of the DOE clean-up effort Selective sequestration of cesium has been addressed by polymer-bound crown ethers e.g. the SuperLig 644) and the crystalline silicotitanates. While both of these methods are effective, they each have their drawbacks. By lining the pores of SAMMS with ferrocyanide complexes, it is possible to remove all the cesium from waste simulant solutions in a matter of minutes [12]. This sorbent is not... 

Since disease symptoms are attributed to the toxins released by C. difficile, and re-colonization of C. difficile is attributed to the inhibition of normal microbial flora growth by antibiotic treatment, selective sequestration and neutrahzation of these toxins appears to be an attractive and safe antibiotic-... 

Selective sequestration of proteases by modified fibers to reduce excessive protease concentrations in the chronic wound provides an approach that is less likely to be complicated by potential drug reactions associated with a synthetic inhibitor or... 

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