72
D. Lahiri et al.
2.5 Phenol Coefficient
The phenol coefficient was measured spectrophotometrically at 540 nm by treating
the culture of B. cereus with 5 mL of ethanolic extract of A. cepa and phenol for
different time periods (Eliasa et al. 2013).
2.6 Study of the Quorum Sensing of the Isolated Bacteria
from Throat
The supernatant of bacterial culture broth filtered through 0.2 µm membrane filter
was mixed with ethyl acetate and shaken for 10 min for phase separation. The upper
part of the solution was mixed with 1:1 mixture of 2 M hydroxyl amine and 3.5 M
NaOH and later with 10 µl of 1:1 Ferric Chloride and 95% ethanol. OD was measured
at 520 nm (Yang et al. 2006).
2.7 Determination of Viability Count of the Biofilm Forming
Isolated Bacterial Cells
The colonies of working strains were scrapped from the biofilm formed on the surface
of chitin flakes and were inoculated in LB broth having 0.1% (W/V) of chitin flakes
to re-grow for a period of 72 h. After adequate washing, the planktonic cells were
removed and the cultures of the working strains were treated with the required concentration of ethanolic extract of A. cepa and standard antibiotic Azithromycin in three
different flasks and the data were noted in 2–24 h of time challenge (Gomes et al.
2012).
2.8 Scanning Electron Microscopy (SEM)
Biofilms were grown on glass coverslips by the treated and untreated cultures
of isolated bacteria from throat. The effect of plant extract on biofilm formation
was visualized under a scanning electron microscope (Model-ZEISS EVO-MA 10)
(Andersson et al. 2009; Singh et al. 2013).
D. Lahiri et al.
2.5 Phenol Coefficient
The phenol coefficient was measured spectrophotometrically at 540 nm by treating
the culture of B. cereus with 5 mL of ethanolic extract of A. cepa and phenol for
different time periods (Eliasa et al. 2013).
2.6 Study of the Quorum Sensing of the Isolated Bacteria
from Throat
The supernatant of bacterial culture broth filtered through 0.2 µm membrane filter
was mixed with ethyl acetate and shaken for 10 min for phase separation. The upper
part of the solution was mixed with 1:1 mixture of 2 M hydroxyl amine and 3.5 M
NaOH and later with 10 µl of 1:1 Ferric Chloride and 95% ethanol. OD was measured
at 520 nm (Yang et al. 2006).
2.7 Determination of Viability Count of the Biofilm Forming
Isolated Bacterial Cells
The colonies of working strains were scrapped from the biofilm formed on the surface
of chitin flakes and were inoculated in LB broth having 0.1% (W/V) of chitin flakes
to re-grow for a period of 72 h. After adequate washing, the planktonic cells were
removed and the cultures of the working strains were treated with the required concentration of ethanolic extract of A. cepa and standard antibiotic Azithromycin in three
different flasks and the data were noted in 2–24 h of time challenge (Gomes et al.
2012).
2.8 Scanning Electron Microscopy (SEM)
Biofilms were grown on glass coverslips by the treated and untreated cultures
of isolated bacteria from throat. The effect of plant extract on biofilm formation
was visualized under a scanning electron microscope (Model-ZEISS EVO-MA 10)
(Andersson et al. 2009; Singh et al. 2013).