Hexavalent chromium reduction was examined under microaerophilic
(static) condition in 100 mL LB broth amended with suitable concentration of Cr(VI) (3mM- inoculum size) and inoculated with appropriate cells of bacterial suspension (10% inoculum-chromate concentration experiment), incubated at 35[degrees]C.
These reference strains were cultivated in blood agar at 42 [+ or -] 0.5[degrees]C for 48h under microaerophilic
With the aid of sterile forceps, cephalothin and nalidixic acid discs were placed on the surface of inoculated plate and incubated at 37[degrees]C for 3-6 days under microaerophilic
, helical shaped Gramnegative bacteria.
128 experimental systems were incubated in a moist chamber at 37 [degrees]C under two different atmospheres: 64 in aerophilic atmosphere and 64 in microaerophilic
(10 % C[O.sub.2]).
They were incubated at 32[degrees]C for 8 weeks under microaerophilic
mutans ATCC 25175 was routinely grown under microaerophilic
conditions for 48 h at 37[degrees]C in agar plates with 32 g/L of Brain Heart Infusion (BHI) (Bacto, Difco[R], USA) and supplemented with 3 g/L of yeast extract and 200 g/L of sucrose (Bacto, Difco, USA).
The incubation time was 48 h under microaerophilic
conditions (85% N2,10% C[O.sub.2], and 5% O2) at 37[degrees]C.
Prior to testing, one vial of each strain was removed from the freezer and subcultured twice on Brain Heart Infusion (BHI) blood agar plates (Oxoid) and incubated for 24 h at 37[degrees]C in a microaerophilic
atmosphere, in order to ensure its purity and vitality.
The strain was grown for 48 h at 37[degrees]C incubated under microaerophilic
conditions which correspond to the logarithmic growth phase.
Although identification of this Gram-negative, microaerophilic
bacterium from gastric biopsy specimens and 13C-urea breath test has higher sensitivities and specificities, these test require direct observation, trained staff and expensive instruments.
Helicobacter pylori (H pylori is a microaerophilic
, spiral-shaped bacteria that primarily colonizes the antral gastric mucosa where it causes an acute and chronic inflammation.