scence whereas similar amount of DCS just diminished the fluorescence. It is notable that effect of PYZ was more pronounced as compare to DCS towards aggregation inhibition. These results further confirm ThT fluorescence spectroscopic measurement findings. 3.4. Effect of PYZ and 
DCS on HEWL aggregates examined by transmission electron microscopy Fig 4A4F, showed the micrographs of HEWL, 120 h aged HEWL, 120 h aged HEWL in presence of 125 and 500 M each of PYZ and DCS. As shown in Fig 4A and 4B, the Anti-Amyloid Behavior of Pyrazinamide and D-Cycloserine Fig 4. Transmission electron micrographs. HEWL HEWL incubated at 65C for 120 h HEWL incubated at 65C for 120 h in presence of 125 M PYZ HEWL incubated at 65C for 120 h in presence of 500 M PYZ HEWL incubated at 65C for 120 h in presence of 125 M DCS HEWL incubated at 65C for 120 h in presence of 500 M DCS. However presence of 125 M PYZ and DCS decreased amyloid fibrillization that got markedly diminish at 500 M of the PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19731986 two drugs. Evidently, the inhibition of amyloid fibrillization of 120 h aged HEWL was more pronounced in presence of PYZ which further confirm more potency of PYZ towards inhibition of amyloid fibrillization of HEWL. 3.5. Effect of PYZ and DCS on secondary structure of HEWL studied by Far-UV circular dichroism As can be seen from Fig 5 and helix and 11% -sheet). After MedChemExpress Zotarolimus incubation at 65C for 120 h, the HEWL displayed a structural transition from -helix to -sheet conformation. This structural transition from -helix to -sheet conformation indicates the formation of amyloid fibrils in HEWL. To know the inhibitory effect of DCS and PYZ, far UV CD measurements of 120 h aged HEWL incubated with varying concentration of both drugs individually 10 / 21 Anti-Amyloid Behavior of Pyrazinamide and D-Cycloserine were taken. The calculated percent secondary structure contents are summarized in 3.6. Effect of PYZ and DCS on HEWL aggregation examined by Congo red binding assay Fig 6 shows an increase in absorbance with absorption maxima at 540 nm. The increase in absorbance with red shift is a characteristic feature of amyloid formation and thus it shows that Congo red binds to matured fibril of HEWL. However, incubation with 500 M PYZ and DCS led to decrease in absorbance with absorption maxima at around 501 nm and 510 nm along with blue shift of approximate 40 and 30 nm. The decrease in absorbance and shift was concentration-dependent and thus indicate the inhibitory action of drugs against HEWL fibrillation; though more pronounced effect is of PYZ. 3.7. PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19728767 Effect of PYZ and DCS on HEWL aggregation by ANS fluorescence measurements As shown in Fig 7, the ANS fluorescence of HEWL at zero hour exhibited negligible intensity at 480 nm which confirm the absence of exposed hydrophobic patches. However, HEWL after incubation at 65C for 120 h resulted in an increase in ANS fluorescence due to exposure of hydrophobic patches as a consequence of amyloid fibrillization. Incubation of PYZ and DCS with HEWL resulted in a significant depreciation of ANS fluorescence in concentrationdependent manner which indicates the reduction in hydrophobic patches exposure. However, the decrement in ANS fluorescence of 120 h aged HEWL amyloid fibrils was more pronounced in presence of PYZ as compared to DCS. It was evident from the Fig 7 that there were around 37.5 and 81% reduction in ANS fluorescence in presence of 125 and 500 M of PYZ whereas 22.5 and 50% in presence of similar amount of DCS, respectively. This reduc