Question

Culture medium contains two carbon sources, one is preferred carbon source (glucose) and the second is a non-preferred source (lactose).Which one below is correct regarding the nature of growth curve of



e. Coli cultured in this medium?



a. Growth curve will be same as when grown in presence of only glucose.



b. Growth curve will be same as when grown in presence of only lactose.



c. A lag phase will be observed between the two exponential phases.



d. Two lag phases will be observed between the two exponential phases.

Answer 1

Coon's Modification; Fischer's Medium; H-Y Medium (Hybri-Max®); Iscove's Modified Dulbecco's Medium (IMDM); McCoy's 5A Modified Medium; MCDB Media; Medium 199; Minimum Essential Medium Eagle (EMEM); NCTC Medium; Nutrient Mixture, Ham's F-10; Nutrient Mixture, Ham's F-12; Nutrient Mixture Ham's F-12 Kaighn's Modification (F12K); RPMI-1640; Serum-Free/Protein Free Hybridoma Medium; Waymouth Medium MB; Williams Medium E and various proprietary media. L-15 Medium contains galactose in place of glucose.

The amount of glucose in cell culture formulations ranges from 1 g/L (5.5 mM) to as high as 10 g/L (55 mM). Many classical media are supplemented with approximately 5.5 mM D-glucose which approximates normal blood sugar levels in vivo. These media include: Ames' Medium; Basal Medium Eagle (BME); Click's Medium; CMRL-1066 Medium; Fischer's Medium; Medium 199; Minimum Essential Medium Eagle (EMEM); NCTC Medium; and Swim's S-77 Medium. The MCDB media series contain glucose in the range from 3.9 to 10 mM. F-12 Coon's Modification contains 10 mM and RPMI-1640 and Williams Medium E contain 11 mM glucose.

Concentrations of glucose approaching 10 mM are pre-diabetic levels. Concentrations of glucose above 10 mM are analogous to a diabetic condition within the cell culture system. This is important because the same processes that can affect cells and molecules in vivo can occur in vitro. The consequence to growing cells under conditions that are essentially diabetic is that cells and cell products are modified by the processes of glycation and glyoxidatio