Cholinesterase inhibitor (Altenuene) from an endophytic fungus Alternaria alternata: optimization, purification and characterization.

AIMS: The aim of this study was to screen endophytic fungi isolated from Vinca rosea for their potential to produce acetylcholinesterase (AChE) inhibitors. METHOD AND RESULTS: Endophytic fungi isolated from V. rosea (Catharanthus roseus), were screened for AChE inhibitor production using Ellman's method. Maximum inhibition against AChE (78%) was observed in an isolate VS-10, identified to be Alternaria alternata on morphological and molecular basis. The isolate also inhibited butyrylcholinesterase (73%). Significant increase (1·3 fold) was achieved after optimization of process parameters using one variable at time approach. The inhibitor was purified using chromatographic techniques. The structure elucidation of the inhibitor was carried out using spectroscopic techniques and was identified to be 'altenuene'. The purified inhibitor possessed antioxidant potential as revealed by dot blot assay. The insecticidal potential of purified inhibitor was evaluated by feeding Spodoptora litura on diet amended with inhibitor. It evinced significant larval mortality. CONCLUSIONS: Endophytic A. alternata can serve as a source of dual cholinesterase inhibitor 'altenuene' with significant antioxidant and insecticidal activity. This is the first report on acetylcholinestearse inhibitory activity of altenuene. SIGNIFICANCE AND IMPACT OF THE STUDY: Alternaria alternata has the potential to produce a dual ChE inhibitor with antioxidant activity useful in the treatment of neurodegenerative disorders and in agriculture as biocontrol agent.

Genotoxic potency of mercuric chloride in gill cells of marine gastropod Planaxis sulcatus using comet assay.

In vivo and in vitro exposures were used to investigate the genotoxicity of mercuric chloride (HgCl2) to the marine snail, Planaxis sulcatus. The comet assay protocol was validated on gill cells exposed in vitro to hydrogen peroxide (H2O2, 0-50 µM). Snails were exposed in vivo for 96 h to HgCl2 (10, 20, 50, and 100 µg/l). Our results showed significant concentration-dependent increase in the tail DNA (TDNA) and olive tail moment (OTM) in exposed snails for all doses compared with controls. In vitro exposure to HgCl2 (10-100 µg/l) resulted in significantly higher values for TDNA at all concentrations. Our results showed that DNA damage increased in the gill cell with increasing exposure time. This study demonstrates the usefulness of comet assay for detection of DNA damage after exposure to HgCl2 and the sensitivity of marine snail P. sulcatus as a good candidate species for metal pollution.

RADIOIODINE THERAPY FOR DIFFERENTIATED THYROID CARCINOMA : INHS ASVINI EXPERIENCE.

During last 17 years, 175 patients of carcinoma thyroid were treated in this centre. Hundred patients (57%) of papillary carcinoma formed majority. Fifty four patients (31%) were follicular carcinoma and 15 (8.5%) were mixed variety. Two (1.3%) were medullary carcinoma, 3 (1.7%) anaplastic type and 1 (0.5%) hurthle cell carcinoma. After surgery these patients were assessed for radio iodine uptake, residual thyroid tissue and distant metastasis which determined the dose of radioiodine for ablation. Fifty two per cent (91) patients presented as multi nodular goitre, 22.3 per cent (39) as solitary nodule, 13.7 per cent (24) had lymph node metastasis, 5.7 per cent (10) bone metastasis, 2.5 per cent (4) had lung metastasis and 3.8 per cent (7) presented as thyrotoxicosis. Average number of therapy for complete ablation in papillary carcinoma was 1.5, follicular 1.78 and mixed variety 1.5. 72.6 per cent cases (127) needed single dose for ablation, 14.9 per cent (26) needed 2 doses and 5.7 per cent (10) required 3 doses. Only 6.8 per cent (12) cases needed 4 to 8 doses. Average dose of I-131 administered for ablation was 157 mci in males and 124 mci in females of papillary carcinoma thyroid. Males in follicular variety required 204 mci and females needed only 120 mci. In mixed variety males required 177 mci and females required 62.5 mci for complete ablation. 144 patients (82.3%) were followed up to 5 years and remaining patients from 6 to 17 years. These patients are followed up once in a year or alternate years. Follow-up and medical record keeping for defence personnel is done with meticulous care, therefore followup results are very encouraging.