1. What is Transformation Efficiency?

Transformation efficiency is a measure of how effectively foreign DNA is taken up by competent cells, expressed as colony forming units (CFU) per microgram of DNA (cfu/μg). It indicates the success of a transformation experiment in molecular biology.

2. How Does the Calculator Work?

The calculator uses the transformation efficiency formula:

Where:

• \( CFU \) — Number of colony forming units observed
• \( \mu g \text{ DNA} \) — Amount of DNA used in the transformation (micrograms)

Explanation: The equation calculates how many bacterial colonies were formed per microgram of DNA used in the transformation protocol.

3. Importance of Transformation Efficiency

Details: Transformation efficiency is crucial for assessing the quality of competent cells and the success of cloning experiments. High efficiency (>1×10⁸ cfu/μg) is needed for challenging applications like library construction.

4. Using the Calculator

Tips: Count colonies carefully from appropriate dilution plates. Use the actual amount of DNA that reached the cells (accounting for dilutions). Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is a good transformation efficiency?
A: For routine cloning, 1×10⁶ to 1×10⁸ cfu/μg is acceptable. For demanding applications, >1×10⁸ cfu/μg is preferred.

Q2: Why is my transformation efficiency low?
A: Possible causes include poor quality DNA, improper heat shock, old competent cells, or incorrect antibiotic concentration.

Q3: Should I use the total DNA amount or just the insert amount?
A: Use the total DNA amount that was added to the competent cells.

Q4: How many colonies should I count?
A: Ideally count plates with 30-300 colonies for accuracy. Use appropriate dilutions to achieve this range.

Q5: Does this work for electrocompetent cells?
A: Yes, the same calculation applies for both chemically competent and electrocompetent cells.