ChIP Anti-bodies

The process of RNA extraction from bacteria, in general, involves an RNA-protective, effective lysis of bacterial cell wall (which may pose difficulties). EDTA promotes loss of outer membrane to provide lysozyme with access to peptidoglycan. Another common method for cell wall lysis is mechanical disruption using a homogenizer (applied for gram-positive bacteria and some strains of gram-negative bacteria). Following lysis, it is necessary to disrupt protein-nucleic acid interactions, which can be achieved by adding sodium dodecyl sulfate (SDS). Next step involves using phenol-chloroform-isoamyl alcohol extraction, where RNA can be obtained from the bottom organic phase, the top phase consists of DNA and the interphase contains proteins. Isoamyl alcohol is an inert and optional addition to this mixture and is added as an anti-foaming reagent to reduce the interphase. Following RNA extraction, the samples should be checked for its quality by gel electrophoresis (23S and 16S rRNAs and 5s rRNA and tRNA bands) or UV spectrophotometric or fluorescence methods.

The process of RNA extraction from bacteria, in general, involves an RNA-protective, effective lysis of bacterial cell wall (which may pose difficulties). EDTA promotes loss of outer membrane to provide lysozyme with access to peptidoglycan. Another common method for cell wall lysis is mechanical disruption using a homogenizer (applied for gram-positive bacteria and some strains of gram-negative bacteria). Following lysis, it is necessary to disrupt protein-nucleic acid interactions, which can be achieved by adding sodium dodecyl sulfate (SDS). Next step involves using phenol-chloroform-isoamyl alcohol extraction, where RNA can be obtained from the bottom organic phase, the top phase consists of DNA and the interphase contains proteins. Isoamyl alcohol is an inert and optional addition to this mixture and is added as an anti-foaming reagent to reduce the interphase. Following RNA extraction, the samples should be checked for its quality by gel electrophoresis (23S and 16S rRNAs and 5s rRNA and tRNA bands) or UV spectrophotometric or fluorescence methods.

The process of RNA extraction from bacteria, in general, involves an RNA-protective, effective lysis of bacterial cell wall (which may pose difficulties). EDTA promotes loss of outer membrane to provide lysozyme with access to peptidoglycan. Another common method for cell wall lysis is mechanical disruption using a homogenizer (applied for gram-positive bacteria and some strains of gram-negative bacteria). Following lysis, it is necessary to disrupt protein-nucleic acid interactions, which can be achieved by adding sodium dodecyl sulfate (SDS). Next step involves using phenol-chloroform-isoamyl alcohol extraction, where RNA can be obtained from the bottom organic phase, the top phase consists of DNA and the interphase contains proteins. Isoamyl alcohol is an inert and optional addition to this mixture and is added as an anti-foaming reagent to reduce the interphase. Following RNA extraction, the samples should be checked for its quality by gel electrophoresis (23S and 16S rRNAs and 5s rRNA and tRNA bands) or UV spectrophotometric or fluorescence methods.

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The biggest problem in isolating RNA from gram-positive bacteria is the disruption of the cell wall. A lot of protocols employ enzymatic digestion (pretreatment) which may affect gene expression patterns of certain genes. Therefore physical disruption using beads can be a best alternative.

A restriction enzyme or restriction endonuclease is defined as a protein that recognizes a specific, short nucleotide sequence and cuts the DNA only at or near that site, known as restriction site or target sequence. The four most common types of restriction enzymes inclue: Type I (cleaves at sites remote from a recognition site), Type II (cleaves within or at short specific distances from a recognition site), Type III (cleave at sites a short distance from a recognition site), and Type IV (targets modified DNA- methylated, hydroxymethylated and glucosyl-hydroxymethylated DNA). The most common challenges with restriction digest include- 1. inactivation of enzyme, 2. incomplete or no digestion, and 3. unexpected cleavage. The enzyme should always be stored at -20C and multiple freeze-thaw cycles should be avoided in order to maintain optimal activity. Always use a control DNA digestion with the enzyme to ensure adequate activity (to avoid interference due to high glycerol in the enzyme). For complete digestion, make sure that the enzyme volume is 1/10th of the total reaction volume, optimal temperature is constantly maintained throughout the reaction, the total reaction time is appropriately calculated based on the amount of DNA to be digested, appropriate buffers should be used to ensure maximal enzymatic activity, and in case of a double digest, make sure that the two restriction sites are far enough so that the activity of one enzyme cannot interfere with activity of the other. Star activity (or off-target cleavage) and incomplete cleavage are potential challenges which may occur due to suboptimal enzymatic conditions or inappropriate enzyme storage. To avoid these, follow the recommended guidelines for storage and reactions, and always check for the efficacy of digestion along with purification of digested products on an agarose gel.

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Get tips on using RNeasy Mini Kit to perform RNA isolation / purification Bacteria - Gram positive Bacillus anthracis

Protein isolation is a technique that involves isolation and/ or purification of protein from cells or tissues via chromatography or electrophoresis. The major challenges in protein isolation include: 1. The concentration of proteins in cells is variable and tends to be small for some intracellular proteins. Unlike nucleic acids, proteins cannot be amplified. 2. Proteins are more unstable than nucleic acids. They are easily denatured under suboptimal temperature, pH or salt concentrations. 3. Finally, no generalized technique/protocol can be applied for protein isolation. Proteins may have different electrostatic (number of positively or negatively charged amino acids) or hydrophobic properties. Therefore, protein purification requires multiple steps depending on their charge (a negatively charged resin/column for positively charged proteins and vice-versa), dissolution (using detergents) and unlike in the case of DNA and RNA, instead of using salts, proteins should be isolated by isoelectric precipitation.