| Timentin is a suitable antibiotic for Agrobacterium counterselection and a mixture of two antibiotics: ticarcillin and clavulanic acid. Most wild Agrobacterium isolates have beta-lactamase activity which clavulanic acid exhibits activity towards. Many Agrobacterium isolates are highly susceptible to Timentin. Agrobacterium strains carrying the standard pBR beta-lactamase gene are also Timentin (clavulanic acid) susceptible. Timentin killing of Agrobacterium wild-type strains is three logs greater than with comparable doses of carbenicillin. In plant transformation experiments, 0.1mg/ml Timentin (15:1) is sufficient to counterselect Agrobacterium. The appropriate dose in tissue culture medium is 0.1 mg/ml (not 0.1 mg/liter) of 15:1 mixture or 0.2 mg/ml of 30:1 mixture. To improve efficacy (of any antimicrobial), solid media are best slightly dried before use. At these concentrations, Timentin exhibits no phytotoxicity to Arabidopsis root cultures. Ticarcillin Disodium/Potassium Clavulanate =15:1 Synonyms: Timentin, Ticarcillin, MM 14151, [2R-(2alpha,3Z,5alpha)]-3-(2-hydroxyethylidene)-7-oxo-4-oxa- 1-azabicyclo[3.2.0]heptane-2-carboxylate disodium/potassium salt CAS No: 4697-14-7,61177-45-5 Assay (HPLC): 750ug/mg (ticarcillin, on dried basis) 50ug/mg (clavulanic acid, on dried basis) Appearance: White to off-white to slight yellow powder Identification (HPLC): Positive Solubility: Colorless, clear, complete Moisture (Karl-Fischer): 4.2% pH: 5.5-7.5 Related Substances: Largest impurity: 4% Second impurity: 2.5% Storage and Stability: Store at 4C in hermetically sealed container, protected from light. Stable for 12 months after receipt at 4C. |
