Can someone please help explain in a step by step process how to do this problem and what it means? I do not understand what it is asking for exactly in regards to positive, negative, and the resistance gene and so forth...especially about the media being selective. What does being selective mean?
1) Pretend you are a microbiologist and need to grow E. cold strains of different genotypes. For the following bacterial genotypes, indicate which amino acids, carbohydrates, and antibiotics, should be added to a bacterial growth media to provide both a media that will allow the bacteria to live and also a media that is the most selective media possible for that particular strain of bacteria. Indicate whether an ingredient is required for survival of a particular strain, whether it is added to be selective for a particular strain, or both.
his=histidine, trp=tryptophan, gal=galactose, amp=ampicillin, lac=lactose
Ingredients available for the media:
Amino acids: histidine, tryptophan
Carbohydrates: galactose, lactose, glucose
Antibiotics: ampicillin, tetracycline
Bacterial Genotypes:
1. his+, gal-, amp^r, tets^s, trp-, lac-
2. his-, gal-, amp^r, tet^r, trp-, lac-
3. his-, gal-, amp^r, tet^r, trp+, lac+
4. his+, gal-, amp^s, tet^s, trp-, lac-