Physiological efficiency model

The objective of this chapter is to describe larval digestive efficiency and growth performance of phytophagous insects in relation to the chemical composition of their foodplants, and to discuss various insect adaptations (primarily behavioral and biochemical) which may improve the suitability of plant tissues for larval survival and growth. A physiological efficiency model is presented in relation to ecological and evolutionary interpretations of insect-plant interactions, with particular emphasis on a feeding specialization hypothesis. 

A Physiological efficiency model of plant suitability based upon a leaf water/nitrogen index ... 

USE OF THE PHYSIOLOGICAL EFFICIENCY MODEL INTERPRETATIONS OF THE FEEDING SPECIALIZATION HYPOTHESIS... 

A physiological efficiency model of insect response to plant chemistry is proposed using the water-nitrogen index. This larval performance model incorporates seasonal trends in various plant growth forms and provides an... 

Operational model, devised and published by James Black and Paul Leff (Proc. R. Soc. Lond. Biol. 220,141-162, 1983), this model uses experimental observation to describe the production of a physiological response by an agonist in general terms. It defines affinity and the ability of a drug to induce a response as a value of x, which is a term describing the system (receptor density and efficiency of the cell to convert an activated receptor stimulus into a response) and the agonist (efficacy). It has provided a major advance in the description of functional effects of drugs see Chapter 3.6 for further discussion. 

Even with the uncertainty in E2 active-site position, the models have suggested that there would be no E3 residues near the E2 active site, in agreement with the observations made in the c-Cbl-E2 structure. This again ruled out the possibility that the SCF E3 provides acid/base catalysis and the possibility that the SCF positions the -amino group of the lysine at the E2 active site [66]. The only plausible mechanism left accounting for the catalysis mediated by the SCF in substrate ubiq-uitination is that the E3 complex helps increase the effective concentration of a portion of the substrate that contains the physiological ubiquitination-site lysine at the E2 active site. This model made the testable prediction that the distance between the destruction motif and the ubiquitinated lysine is a determinant of the ubiquiti-nation efficiency. 

A different redox system model - the model for NADH - was also described by our group. [16] As electron transfer mediators, FMN and FAD accept two electrons from NAD(P)H and transfer one electron to metal centres in heme-containing proteins, nonheme iron, or molybdenum sites. However, the transfer of electrons between reduced pyridine - dinucleotide cofactors is slow under physiological conditions and must be catalysed by enzymes. Function of these enzymes was mimicked by a modification of the cofactor by a recognition site for its counterpart and, thus, efficient electron transfer was enabled directly. Functionalised 1,4-dihydronicotinamides bearing a recognition unit for flavins were synthesised (Scheme 18). 

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