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Phenolic compounds such as catechol and resorcinol are toxic and persistent pollutants in the aqueous environment. Detection procedures such as chromatographic and spectrophotometric methods are time-consuming and require sophisticated instruments with skilled manpower. Development of a simple, cost effective, portable and disposable paper based biosensor could be a better alternative to the conventional methods. The present study attempted to develop a paper based biosensor by immobilizing horseradish peroxidase enzyme to detect catechol and resorcinol in aqueous samples. Horseradish peroxidase catalyzes the oxidation of phenolic compounds to semiquinones, which on reaction with a chromogen, 3-methyl 2-benzothiazolinone hydrazine (MBTH) gives faint pink to red color depending on the compound and its concentration in the sample is the basis for biosensing application. Different methods of enzyme immobilization on filter paper like physical adsorption, covalent coupling, and polysaccharide entrapment were executed. The performance of the various enzyme immobilization methods was evaluated by analyzing the developed color intensity using ImageJ software. Entrapment technique is the most effective method of immobilizing enzyme on the filter paper that produces the highest color intensity with better stability. The visible limit of detection (LoD) was observed as 0.45 mM (50 mg/L) for catechol and 0.09 mM (10 mg/L) for resorcinol in aqueous samples.

To study the effect of entacapone, a specific peripherally acting catechol-O-methyltransferase (COMT) inhibitor used in combination with levodopa treatment, in cases of Parkinson's disease with both fluctuating and non-fluctuating response to treatment.A randomised, placebo controlled, double blind, six month study was undertaken in 172 fluctuating and 128 non-fluctuating patients. The clinical efficacy and safety of 200 mg entacapone given with each daily levodopa dose was studied. Efficacy was examined using home diaries, the unified Parkinson disease rating scale (UPDRS), and recording of daily levodopa dose.The primary efficacy variable for fluctuating patients-the proportion of daily ON time-showed a significant increase compared with placebo (p0.05). The absolute ON time (mean (SD)) increased from 9.5 (2.5) to 10.8 (2.4) hours (p0.01), and the daily OFF time was correspondingly reduced from 7.0 (2.6) to 5.9 (2.5) hours (p0.05 v placebo). This improvement was achieved despite a reduction in daily levodopa requirements. The effect was rapidly lost on withdrawal of entacapone. In non-fluctuating patients, the primary efficacy measure was part II of the UPDRS (activities of daily living; ADL). In this group of patients, ADL scores improved in the entacapone group (p0.01 v placebo), and there was also a 40 mg reduction in levodopa requirement (p0.01 v placebo). Entacapone was well tolerated by both fluctuating and non-fluctuating patients.The ability of entacapone to provide additional benefits to levodopa treatment in increasing ON time in fluctuating Parkinson's disease patients was confirmed. A novel finding was that patients without fluctuations also obtained benefit from the addition of entacapone to their levodopa treatment, as evidenced by improved ADL scores and a relatively reduced levodopa requirement.

Mutants of Escherichia coli K-12 blocked in each of the three enzymatic reactions between chorismate and 2,3-dihydroxybenzoate, in the pathway leading to the iron-sequestering compound enterochelin, have been isolated and biochemically characterized. The three genes concerned (designated entA, entB and entC ) have been shown to be clustered on the chromosome between purE and gal and to be located near minute 14 by cotransduction with the purE, lip , and fep genes. entA, entB , and entC were shown to be the structural genes for 2,3-dihydro-2,3-dihydroxybenzoate dehydrogenase, 2,3-dihydro-2,3-dihydroxybenzoate synthetase, and isochorismate synthetase, respectively.