Selection of Chloramphenicol-Resistant Transformants: Plating heat-shock or electroporated cells on LB agar (1.0% Tryptone, 0.5% Yeast Extract, 1.0% NaCl, 1.5% agar) with 20 µg/mL chloramphenicol to recover and select clones carrying cat-marked plasmids.

Plasmid Maintenance in Escherichia coli: Routine propagation and stability of chloramphenicol-resistant plasmids and shuttle vectors in laboratory strains of Escherichia coli.

BAC/Cosmid/PAC Propagation: Culturing bacterial artificial chromosomes and other large cat-marked vectors that require chloramphenicol selection.

Colony Screening Under Selection: Picking colonies for colony PCR, restriction analysis, or sequencing while maintaining chloramphenicol pressure to ensure plasmid retention.

Conjugation and Transduction Selection: Selecting chloramphenicol-resistant transconjugants or transductants after genetic exchange experiments.

Strain Preservation and Restreaking: Streaking for single colonies and maintaining pure cultures under chloramphenicol selection.

Transformation Efficiency Assays: Quantifying competent cell performance by plating on chloramphenicol-selective LB agar.

Selection in Enterobacteriaceae: Growth and maintenance of cat-marked constructs in organisms such as Escherichia coli and Salmonella enterica on standard LB with 20 µg/mL chloramphenicol.

Gram-Positive Shuttle Vector Maintenance (as applicable): Supporting cat-containing shuttle vectors in organisms like Bacillus subtilis under chloramphenicol selection when LB is acceptable for the host.

Contamination Control During Clone Work: Suppressing growth of chloramphenicol-sensitive background flora while recovering resistant clones.