Absorbance assay at 280 nm. This method is just as convenient as for absorbance at 280 nm. It may be preferred if there is excessive contamination by nucleic acids, since nucleic acids absorb very little radiation at 205 nm. Setting the wavelength is a bit tricky since 205 nm is right on the shoulder of the protein peak. - [Read Absorbance Assay 205 nm]
Absorbance assays are fast and convenient, since no additional reagents or incubations are required. No protein standard need be prepared. The assay does not consume the protein. The relationship of absorbance to protein concentration is linear. Because different proteins and nucleic acids have widely varying absorption characteristics there may be considerable error, especially for unknowns or protein mixtures. - [Read Absorbance Assay 280 nm]
Extreme care should be used to identify and verify positive reactions, however, because cross-reactions are common. Counterstaining is essential for examining worms by immunofluorescence and is used to identify the exact cell in which an antigen appears. Methods for counterstaining include labeling all cells with a fluorescent dye that is specific for nucleic acids (e.g., DAPI or propidium iodide) and using GFP driven by tissue-specific promoters. - [Read Antibody Addition and Detection for Staining Caenorhabditis elegans Protocol]
This protocol describes a stepwise procedure to prepare nucleic acids encapsulated in a polyethylene glycol (PEG)-shielded nanolipoparticle (NLP) that contain a bioresponsive lipid and ligand. This process provides several advantages for systemic gene delivery. The in vivo circulation time is extended. Also, low pH-sensitive lipids enhance DNA unpacking and endosomal escape. Finally, ligands inserted into the NLP surface can target gene delivery to specific tissues or cells in vivo. - [Read Bioresponsive Targeted Charge Neutral Lipid Vesicles for Systemic Gene Delivery Protocol]
This protocol describes how to use DIG Chem-Link to directly label any DNA [e.g. plasmids, PCR products, cDNA prepared
from mRNA] or RNA (e.g. total RNA, poly(A)+ mMRNA). The
DIG Chem-Link or Biotin Chem-Link may also be used to label oligonucleotides. Includes: Required Purity of DIG Chem-Link Templates; Direct DIG Labeling of mRNA or cDNA with DIG Chem-Link; Key Product Required for Direct Labeling of DNA or RNA; Estimating the Yield of DIG-labeled Nucleic Acids. - [Read Chem-Link Labeling of DNA or RNA with DIG or Biotin Protocol]
Ultrafiltration is an alternative to ethanol precipitation for the concentration and desalting of nucleic acid solutions. It requires no phase change and is particularly useful for dealing with very low concentrations of nucleic acids. This protocol describes the use of the Microcon cartridge, a centrifugal ultrafiltration device, to concentrate and desalt nucleic acid solutions. - [Read Concentrating and Desalting Nucleic Acids with Microconcentrators Protocol]
Protocol used to study secretion of proteins and prostaglandins by endometrium from the cow, ewe, mare, bitch and other species. The technique is also useful for culture of peri-implantation conceptuses and placental tissues for metabolic labelling studies and to obtain conceptus secretory proteins for biological studies.The medium used is called Pig MEM, which is a modified minimum essential medium supplemented with non-essential amino acids, vitamins, insulin and additional glucose. - [Read Culture of Endometrial Explants and Peri-implantation Conceptuses to Monitor Synthesis and Secretion]
The most convenient and commonly used method to visualize DNA in agarose gels is staining with the fluorescent dye ethidium bromide. Ethidium bromide can be used to detect both singleand double-stranded nucleic acids (both DNA and RNA). However, the affinity of the dye for single-stranded nucleic acid is relatively low and the fluorescent yield is comparatively poor. - [Read Detection of DNA in Agarose Gels Protocol]
His Tag Nickel Affinity Chromatography Protocol PDF. The Wallert and Provost Lab. Theory and Introduction: Ni-Affinity Chromatography uses the ability of His to bind nickel. Six histadine amino acids at the end of a protein (either N or C terminus) is known as a 6X His tag. Nickel is bound to an
agarose bead by chelation using nitroloacetic acid (NTA) beads. Several companies produce these beads as His
Tagged proteins are some of the most used affinity tags in today’s market. - [Read His Tag Nickel Affinity Chromatography Protocol PDF]
This method for tagging monoclonal antibodies involves growing hybridomas in the presence of radioactive amino acids. This protocol can be particularly useful when conventional labeling techniques cause the antibody to lose activity. The labeled antibodies that result are essentially identical to the unlabeled antibodies. - [Read Labeling Monoclonal Antibodies by Biosynthesis Protocol]
Lipoplex (cationic liposome-DNA complex) is formed via electrostatic interaction of anionic nucleic acids with cationic liposomes. A thin film of lipids is dried on the bottom of a glass tube and rehydrated in an aqueous solution. The resulting liposome suspension is passed through polycarbonate filters of desired pore size. This protocol also describes the preparation, physical properties, and biological activity of liposome-polycation-DNA (LPD) nanoparticles. - [Read Lipoplex and LPD Nanoparticles for In Vivo Gene Delivery Protocol]
Protocol is the first step in a three-step process for the preparation and enrichment of phosphopeptides using immobilized metal affinity chromatography (IMAC) for the identification of the phosphopeptides by LC-MS/MS. This procedure is used to prepare protein extracts from WEHI-231 cells. This preparation method provides total cellular protein samples that are free of contaminating nucleic acids. - [Read Lysis and Protein Extraction from WEHI-231 Cells with TriPure Isolation Reagent Protocol]
MALDI Matrices. Commonly used MALDI matrices for analysis of peptides, proteins, carbohydrates, and nucleic acids using 337 nm or 355 nm UV lasers. All matrices can be used for sample preparation using the Dried Droplet Method whereas only matrices solubl - [Read MALDI Matrices]
Protocol for Protein Extraction Using Proteomics. Extraction of proteins from plant cells that are rich in compounds that interfere with the 2-Dimensional electrophoretic separation methods such as salts, organic acids, phenolics, pigments, terpenes, among others. A common protocol used in our lab for extraction proteins from plant tissues consists in the homogenization of mortar-grounded material in liquid nitrogen with an extraction buffer. - [Read Protocol for Protein Extraction Using Proteomics]
Protocol describes the standard method for nucleic acid purification by extraction first with phenol:chloroform (optionally containing hydroxyquiniline at 0.1%) and then with chloroform to remove any remaining phenol. The procedure takes advantage of the fact that deproteinization is more efficient when two different organic solvents are used instead of one. - [Read Purification of Nucleic Acids by Extraction with Phenol:Chloroform Protocol]
Protocol for southern hybridization of radiolabeled probes to nucleic acids immobilized on membranes. Protocol describes how to carry out Southern hybridizations at high stringency in phosphate-SDS buffers. Although a wide variety of formats are available, most Southern hybridizations are carried out in heat-sealable bags, roller bottles, or plastic boxes. - [Read Southern Hybridization of Radiolabeled Probes to Nucleic Acids Immobilized on Membranes Protocol]
Spectrophotometric Measurement of Nucleic Acids' Concentration Tool. This bioinformatic program help calculate the concentration of nucleic acids according to optical density (including DNA, RNA, oligonucleotides). Zbio - [Read Spectrophotometric Measurement of Nucleic Acids' Concentration Tool]
This protocol a protocol on how to generate transfected embryonic stem (ES) cell clones. The previous protocol in this series is the Protocol for Electroporation of ES cells. The next protocol in the series is the Protocol on Disaggregation, Expansion, and Freezing of Transfected ES Clones.