Conformational and functional properties of hemoglobin in water–organic cosolvent mixtures: Effect of ethylene glycol and glycerol on oxygen affinity

We report on the effects that the presence of ethylene glycol or glycerol has on the oxygen affinity of hemoglobin. We attribute these effects to an altered equilibrium between T and R quaternary conformations of hemoglobin and separate them into bulk-electrostatic and non-bulk-electrostatic contributions to the standard free-energy difference between the R and T states.     

Detection of Artichoke Latent Virus by an Indirect Dot-ELISA

An indirect Dot-ELISA was compared with DAS-ELISA for detecting Artichoke Latent Virus (ALV) both in purified preparations and in crude sap from “Spinoso sardo” artichoke leaves. Antigen diluted samples (1 μl) were first spotted on nitrocellulose (NC) and polyvinylidene difluoride (PVDF) membranes. After blocking, the membranes were incubated in rabbit anti-ALV IgG, then in goat anti-rabbit IgG—alkaline phosphatase conjugate, and finally exposed to substrate and examined for a coloured precipitate. The minimum detection levels for ALV by Dot-ELISA were 125 pg of purified virus and 1/2,000 dilution of virus-infected sap on NC, and 83.3 pg of purified virus and 1/4,000 dilution of virus-infected sap on PVDF, as compared with 50 ng of purified virus and 1/1,000 dilution of virus-infected sap detectable by DAS-ELISA. This indirect Dot-ELISA proved to be more sensitive and more economical than DAS-ELISA, and can be completed in as little as 5—6 hours.