Since the pH of the culture medium shifts to lower levels during cultivation, it was assumed using a pH-stat method to cultivate at a constant pH value of 5.5 might further enhance CDH production.
A bigger difference can be seen at medium shifts (0.2 to 0.75) where it ranges from -3.35% to 7.11%.
For fluorescence microscopy, cells were grown to OD600 = 0.8 − 1.0 in appropriate selective medium and shifted to SD-N medium for various lengths of time as described (Cheong et al., 2005).
After 3 days, the medium was shifted to a medium containing Leukemia Inhibitory Factor (LIF, Chemicon) (20 ng/ml) and Brain Derived Neurotrophic Factor (BDNF, Peprotech) (20 ng/ml) to pursue the neuronal and glial population maturation in NSC progeny [42].
Using confocal microscopy, the cytosolic eGFP concentration was monitored as cells were exposed to iso-osmotic medium and shifted to a hypotonic medium of identical composition, except for having a lower concentration of the membrane-impermeant compound, mannitol.
On the following day, the medium was shifted to estrogen-free medium containing phenol-red-free RPMI (Invitrogen) and 5% charcoal-dextran-stripped human serum (Hyclone Laboratories) with controls or test material.
The next day, the culture medium was shifted to serum-free culture medium containing 0.02% BSA.
When cells were grown with f/2 medium and shifted to the nitrogen deficient medium, higher cell density was observed and 2.94 g dry wt/L compared to 2.74 g/L of cell density was observed from the 5% oyster shell enriched medium (pH 6.7).
As expected, the maximum attractant signal observed in the CU conditioned medium was shifted to a higher concentration, due to the loss of CU cells during OCC manipulation.
Medium was shifted to DMEM 1% FBS (D1) and cells were counted in triplicate after 24 h and afterwards every 48 h up to 7 days.
