Eosin-protein interaction

Eosinophils are leukocytes that contain characteristic cationic proteins in their granules that bind the acidic dye eosin. In contrast to neutrophils, eosinophils are minority cells in the blood and are predominantly tissue-dwelling cells found at sites in contact with the environment the mucosal surfaces of the lung, gastrointestinal tract, and genitourinary tract. Selective accumulation of eosinophils, as opposed to neutrophils, is one of the major pathological features of the inflammatory response to infection with parasitic helminths, and in several diseases such as asthma, allergic rhinitis, and atopic dermatitis. A key step in leukocyte recruitment is the local production of chemoattractant molecules that orchestrate the adhesive interactions between leukocytes and the vascular endothelium. 

Proteinaceous materials in wines will stain blue-black using Amido Black lOB and pink to red using Eosine Y as described in method A (Section 17.5.1.1). Method B (Section 17.5.1.2) rehes on the interaction of tannin and protein, which forms a visually apparent haze or precipitate. In method B, formation of pronounced haze in the treated sample as compared with a control is indicative of unstable protein (Fig. 17.4). 

CPI labeled with eosin-SCN in the non activated mode restored photophosphorylation in partially depleted EDTA-chloroplasts and fully depleted NaBr-particles (10). Wheras in the case of the EDTA-particles we could observe very slow rotational motion of the reconstituted eosin-CFI relative to the membrane, in NaBr-part ides we could not detect any rotational motion (up to 500 as) of reconstituted eosin-CFI. We also studied the rotational diffusion of another extrinsic protein of the thylakoid membrane, the ferredoxin-NADP-oxidoreductase (ll), which is probably located in the same stromal region of stacked chloroplasts as CPI and we found very rapid rotation (< 1/is). Only after addition of ferredoxin rotational correlation time decreased to 40 /is. This was interpreted to indicate formation of a ternary complex between ferredoxin-NADP-oxidoreductase ferredoxin and PSI. This revealed rather high lipid fluidy in thylakoids. We tend to assume that the low rotational mobility of the CP0-CF1 complex is caused either by self aggregation or strong interaction with other membrane proteins. 

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