Acetylcholinesterase (ChE) sensor based on Prussian blue (PB) modified electrode was developed and tested for the detection of organophosphorus and carbamic pesticides. The signal of the sensor was generated in PB mediated oxidation of thiocholine recorded at +200 mv in DC mode. ChE from electric eel was immobilized by cross-linking with glutaraldehyde in the presence of bovine serum albumin (B...

A bioactive paper-based colorimetric "dipstick" bioassay is reported that is based on acetylcholinesterase (AChE) catalyzed enlargement of gold nanoparticles that are co-entrapped with the enzyme in a sol-gel based silica material that is coated on a functionalized paper substrate. Test solutions containing acetylthiocholine (ATCh) and a Au(III) salt are spotted over the sensing area of the bio...

A simple colorimetric method for determining serum or plasma cholinesterase has been described. The cholinesterase acts on acetyithiocholine to release thiocholine, which reacts with 5:5-dithiobis(2-nitrobenzoic acid) to produce a yellow color. The activity is measured after incubation for 3 mm. at 370; the reaction is stopped by the excess addition of quinidine sulfate. The difference in absor...

Histochemical methods are employed to detect and localize a wide range of enzymes. Even though protein crystallographers do not commonly use this technique, the extensively used colorimetric reaction of Karnovsky was successfully adapted for easy and quick identification of acetylcholinesterase crystals. The method relies on the reduction of ferricyanide to ferrocyanide by thiocholine, released...

This work describes the highly sensitive detection of organophosphorus pesticides employing the cobalt(II) 4,4,4,4-tetrasulfo-phthalocyanine (CoTSPc) macrocycle complex, carbon nanotubes (CNT), and 1-methyl-3-octylimidazolium tetrafluoroborate (OMIM[BF4]). The technique is based on enzyme acetylcholinesterase (AChE) inhibition. The composite was characterized by scanning electron microscopy (SE...

Using the thiocholine method of Koelle and Friedenwald and histological techniques, the otic ganglion in Egyptian spiny mouse (Acomys cahirinus, Desmarest) was studied. The ganglion was found to be a single oval cluster of neurocytes, situated at the medial and posterior surface of the mandibular nerve just above the maxillary artery. The ganglion is composed of typical ganglionic neurons in co...

Hydroxylamine and HPLC methods, measuring in vitro kinetics of enzymatic hydrolysis of acetylcholine or acetylthiocholine by cholinesterases, are described. The hydroxylamine method determines the dependence of substrate concentration vs. time, the HPLC method is able to measure simultaneously the time dependences of substrate and both primary products, choline or thiocholine, and acetic acid. ...

In this study, a proper and reliable fluorometric method is introduced for screening acetylcholinesterase (AChE) its inhibitors, using carbon quantum dots (CQDs) as the signal reporter. Pure, S-doped, P-doped CQDs, were synthesized their recoverable fluorescence quenching properties observed, when exposed to Hg2+, Cu2+, Fe3+ ions, respectively. The study on recovery of emission showed that afte...