Laboratory Experiments in Microbiology (12th Edition) (What's New in Microbiology)
Laboratory Experiments in Microbiology (12th Edition) (What's New in Microbiology)
12th Edition
ISBN: 9780134605203
Author: Ted R. Johnson, Christine L. Case
Publisher: PEARSON
bartleby

Concept explainers

Question
Book Icon
Chapter 31, Problem 2Q
Summary Introduction

To analyze:

If there was no growth on the DNA + E. coli plates, then what will happen.

Introduction:

Transformation is the process in which horizontal gene transfer takes place. For transformation to occur, a cell must be competent to take up the foreign gene. Either the cell is naturally competent, or these are chemically or electrically treated to make them competent.

Expert Solution & Answer
Check Mark

Explanation of Solution

Natural transformation helps bacteria to gain an extra-chromosomal copy of DNA, called a plasmid which provides many antibiotic resistance genes to the host cell. The artificial transformation has various applications in molecular biology and biotechnology, like the expression of large amounts of enzymes or proteins, cloning of a particular gene of interest so that many copies of a gene are available, and others.

Before the transformation, the cells are first made competent. For example, in the transformation of the DH5 alpha strain of e. coli, the cells are first made competent by treating them with calcium chloride and giving heat shock. These cells are then plated on ampicillin LB agar plates to observe whether they have received a foreign DNA insert or not.

If there is no growth on the DNA + Escherichia coli plates, then it indicates transformation has not taken place. This can occur due to the following reasons:

1. Cells have not become competent (competence is the ability of cells to uptake foreign DNA). heat-shock step must be repeated, or different strains of cells must be.

2. DNA of interest might be extracted directly from the plant or mammalian cells and contain methylated cytosine. Methylated cytosine is degraded by many E. coli cells.

3. Too much ligation mixture might have been used. Only 5 micro lire (μl) or less, ligation mixture should be used during transformation.

4. Inefficient ligation might have occurred. To avoid this, vector to insert molar ratio must be changed from 1:1 to 1:10, DNA must be purified to remove contaminants such as salts and EDTA, removal of phosphate before ligation should be done.

Conclusion

Thus, ifthere is no growth on the DNA + Escherichia coli plates, then it indicates transformation has not taken place.

Want to see more full solutions like this?

Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!
Students have asked these similar questions
Why were both “+ DNA” and “- DNA” mixtures prepared and plated?
Is the DNA soluble in the aqueous solution or alcohol?
If insert DNA was obtained by PCR using Taq DNA polymerase, what shape does the end of this DNA fragment have?
Knowledge Booster
Background pattern image
Biology
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biology and related others by exploring similar questions and additional content below.
Recommended textbooks for you
Text book image
Human Anatomy & Physiology (11th Edition)
Biology
ISBN:9780134580999
Author:Elaine N. Marieb, Katja N. Hoehn
Publisher:PEARSON
Text book image
Biology 2e
Biology
ISBN:9781947172517
Author:Matthew Douglas, Jung Choi, Mary Ann Clark
Publisher:OpenStax
Text book image
Anatomy & Physiology
Biology
ISBN:9781259398629
Author:McKinley, Michael P., O'loughlin, Valerie Dean, Bidle, Theresa Stouter
Publisher:Mcgraw Hill Education,
Text book image
Molecular Biology of the Cell (Sixth Edition)
Biology
ISBN:9780815344322
Author:Bruce Alberts, Alexander D. Johnson, Julian Lewis, David Morgan, Martin Raff, Keith Roberts, Peter Walter
Publisher:W. W. Norton & Company
Text book image
Laboratory Manual For Human Anatomy & Physiology
Biology
ISBN:9781260159363
Author:Martin, Terry R., Prentice-craver, Cynthia
Publisher:McGraw-Hill Publishing Co.
Text book image
Inquiry Into Life (16th Edition)
Biology
ISBN:9781260231700
Author:Sylvia S. Mader, Michael Windelspecht
Publisher:McGraw Hill Education