There are also methods for PCR-based cloning, differentiating embryonic stem cells into embryonic bodies, live imaging of mammalian embryos using multiphoton microscopy, and the cloning of pig, cattle, rabbit, and mouse oocytes.
Each readily reproducible protocol is described in step-by-step detail and contains an introduction outlining the principle behind the technique, lists of equipment and reagents, and tips on troubleshooting and avoiding known pitfalls. An accompanying earlier volume, Sperm and Oocyte Analysis, focuses on sperm cells, oocyte analysis, oocyte maturation, fertilization, and preparation techniques.
Life Sciences Cell Biology.
Methods in Molecular Biology Free Preview. In Molecular Toxicology Protocols, researchers from prominent universities and cancer centers around the world describe in detail their best techniques for analyzing genotoxic exposure and the resulting biological effects, including intermediate biomarkers such as DNA and chromosomal damage, mutations in reporter and oncogenes, and the earliest possible detection of cancer.
The authors emphasize analytical methods specifically developed for use in human populations and in cancer patients, or in other in vivo systems such as transgenic mice. Among the applications detailed are the analysis of interactions of chemical and physical agents with cellular macromolecules, especially DNA, the assessment of medically relevant toxicity, and the individualized characterization of genetic damage and repair.
There are also methods to assess and characterize the modulation of this damage and repair through individual differences in specific and genome-wide gene expression, including metabolic profiling and apoptotic capacity. These methods mark a shift in emphasis from studies of the agents themselves to the exposed population, and from studies of small populations with significant known exposures to a single agent, to studies of common diseases, such as breast cancer, caused by normal levels of generalized genotoxic exposure.
There is not a defined line between these disciplines. This is shown in the following schematic that depicts one possible view of the relationships between the fields: . Much of molecular biology is quantitative, and recently much work has been done at its interface with computer science in bioinformatics and computational biology.
In the early s, the study of gene structure and function, molecular genetics , has been among the most prominent sub-fields of molecular biology. Increasingly many other areas of biology intersecting with molecular Biology, focus on molecules, either directly studying interactions in their own right such as in cell biology and developmental biology , or indirectly, where molecular techniques are used to infer historical attributes of populations or species , as in fields in evolutionary biology such as population genetics and phylogenetics.
A foreign gene inserted into a plant can be of a different species or even kingdom. An anticancer antibody that recognizes the cells of lung, breast, and colon cancer had also been successfully expressed in rice and wheat seed [ 24 ]. Sharma and Anirudh Kumar. This endonucleases genome editing involves the introduction of a targeted double-stranded DNA breakage DSB in genome and consequently stimulating the cellular DNA repair mechanisms. To obtain the best experience, we recommend you use a more up to date browser or turn off compatibility mode in Internet Explorer.
There is also a long tradition of studying biomolecules "from the ground up" in biophysics. One of the most basic techniques of molecular biology to study protein function is molecular cloning.
Over the past twenty years, the disciplines of cellular and molecular biology have generated a bounty of the app- cation of the powerful new techniques described in Transgenesis Techniques: Principles and Protocols. . Series Title: Methods in Molecular Biology; Series Volume: 18; Copyright: ; Publisher: Humana. Transgenesis Techniques. Principles and Protocols. Editors; (view affiliations) Book. Part of the Methods in Molecular Biology™ book series (MIMB, volume 18).
A vector has 3 distinctive features: an origin of replication, a multiple cloning site MCS , and a selective marker usually antibiotic resistance. Located upstream of the multiple cloning site are the promoter regions and the transcription start site which regulate the expression of cloned gene. This plasmid can be inserted into either bacterial or animal cells.
Introducing DNA into bacterial cells can be done by transformation via uptake of naked DNA, conjugation via cell-cell contact or by transduction via viral vector. Introducing DNA into eukaryotic cells, such as animal cells, by physical or chemical means is called transfection. Several different transfection techniques are available, such as calcium phosphate transfection, electroporation , microinjection and liposome transfection. The plasmid may be integrated into the genome , resulting in a stable transfection, or may remain independent of the genome, called transient transfection.
DNA coding for a protein of interest is now inside a cell, and the protein can now be expressed. A variety of systems, such as inducible promoters and specific cell-signaling factors, are available to help express the protein of interest at high levels.
Large quantities of a protein can then be extracted from the bacterial or eukaryotic cell. The protein can be tested for enzymatic activity under a variety of situations, the protein may be crystallized so its tertiary structure can be studied, or, in the pharmaceutical industry, the activity of new drugs against the protein can be studied.
The reaction is extremely powerful and under perfect conditions could amplify one DNA molecule to become 1. The PCR technique can be used to introduce restriction enzyme sites to ends of DNA molecules, or to mutate particular bases of DNA, the latter is a method referred to as site-directed mutagenesis.
Gel electrophoresis is one of the principal tools of molecular biology. Proteins can be separated on the basis of size by using an SDS-PAGE gel, or on the basis of size and their electric charge by using what is known as a 2D gel electrophoresis.
The terms northern , western and eastern blotting are derived from what initially was a molecular biology joke that played on the term Southern blotting , after the technique described by Edwin Southern for the hybridisation of blotted DNA. Patricia Thomas, developer of the RNA blot which then became known as the northern blot , actually didn't use the term.
DNA samples before or after restriction enzyme restriction endonuclease digestion are separated by gel electrophoresis and then transferred to a membrane by blotting via capillary action. The membrane is then exposed to a labeled DNA probe that has a complement base sequence to the sequence on the DNA of interest.
These blots are still used for some applications, however, such as measuring transgene copy number in transgenic mice or in the engineering of gene knockout embryonic stem cell lines.
The northern blot is used to study the expression patterns of a specific type of RNA molecule as relative comparison among a set of different samples of RNA. It is essentially a combination of denaturing RNA gel electrophoresis , and a blot. In this process RNA is separated based on size and is then transferred to a membrane that is then probed with a labeled complement of a sequence of interest. The results may be visualized through a variety of ways depending on the label used; however, most result in the revelation of bands representing the sizes of the RNA detected in sample.
The intensity of these bands is related to the amount of the target RNA in the samples analyzed. The procedure is commonly used to study when and how much gene expression is occurring by measuring how much of that RNA is present in different samples. It is one of the most basic tools for determining at what time, and under what conditions, certain genes are expressed in living tissues.
In western blotting , proteins are first separated by size, in a thin gel sandwiched between two glass plates in a technique known as SDS-PAGE. The proteins in the gel are then transferred to a polyvinylidene fluoride PVDF , nitrocellulose, nylon, or other support membrane. This membrane can then be probed with solutions of antibodies.
Antibodies that specifically bind to the protein of interest can then be visualized by a variety of techniques, including colored products, chemiluminescence , or autoradiography. Often, the antibodies are labeled with enzymes. When a chemiluminescent substrate is exposed to the enzyme it allows detection. Using western blotting techniques allows not only detection but also quantitative analysis. Analogous methods to western blotting can be used to directly stain specific proteins in live cells or tissue sections.
The eastern blotting technique is used to detect post-translational modification of proteins. Proteins blotted on to the PVDF or nitrocellulose membrane are probed for modifications using specific substrates. A DNA microarray is a collection of spots attached to a solid support such as a microscope slide where each spot contains one or more single-stranded DNA oligonucleotide fragments. Arrays make it possible to put down large quantities of very small micrometre diameter spots on a single slide.
A variation of this technique allows the gene expression of an organism at a particular stage in development to be qualified expression profiling. This cDNA is then hybridized to the fragments on the array and visualization of the hybridization can be done. Since multiple arrays can be made with exactly the same position of fragments they are particularly useful for comparing the gene expression of two different tissues, such as a healthy and cancerous tissue.
Also, one can measure what genes are expressed and how that expression changes with time or with other factors. There can be anywhere from spots to more than 10, on a given array.