Dual-Antibiotic Selection of Transformants: Plate transformed E. coli to select and maintain plasmids carrying ampicillin- and tetracycline-resistance markers (Amp-100, Tet-20).

Co-Transformation and Co-Maintenance: Select for co-transformed plasmids or dual-marker constructs requiring simultaneous Amp and Tet selection.

Colony Isolation and Screening: Isolate single colonies for downstream verification (e.g., colony PCR, restriction analysis, Sanger prep).

Cloning Workflows: Plate ligation or Gibson/Golden Gate assemblies in E. coli using rich 2×YT nutrients for robust colony growth.

Library Plating: Plate mutant or expression libraries under dual selection to maintain construct integrity across large populations.

CFU Enumeration and Titering: Quantify viable counts of antibiotic-resistant E. coli under Amp-100 and Tet-20 selection.

Protein Expression Pre-Screen: Screen expression clones in E. coli; 2% glucose helps reduce basal expression from lac/T7-based systems via catabolite repression.

Strain Maintenance and Stability: Maintain dual-selectable plasmids/strains to prevent loss of constructs during routine passaging.

CRISPR Editing Selection: Select edited E. coli carrying dual-resistance plasmids (editing and helper backbones).

Glycerol Stock Preparation from Colonies: Pick verified colonies grown under Amp/Tet for long-term strain and plasmid archiving.