Which Water to Use?

by Sapna Chacko

•High quality, DEPC treated, and non-DEPC treated water

•Certified free of endonuclease, exonuclease, and RNase activity

•Available in sizes to suit all your experimental needs

RNase contamination in reagents used for RNA isolation and analysis can contribute to experimental inconsistency and sometimes even experimental failure. In trying to pinpoint the source(s) of RNase contamination, it is easy to overlook the water used in the experiment, either to prepare reagents, or to resuspend precipitated RNA. Even purified water can have a high pH and minerals that can interfere with reactions that require specific salt and pH conditions. Ambion offers three different grades of high quality water: DEPC-treated water, Nuclease-free water (not DEPC-treated) and RT-PCR grade water.

Ambion Certified and Guaranteed Nuclease-free
All Ambion water products are Type II 18 ohm filtered, and are certified to be nuclease-free. Our water undergoes state-of-the-art reverse osmosis filtration and deionization, followed by autoclaving and sterile filtration. Ambion's water purification equipment is subjected to routine maintenance and testing procedures according to rigid ISO 9001 specifications. Finally, in order to be certified nuclease-free, each lot of water is tested for nuclease activity by incubating a sample overnight with a radiolabeled RNA or DNA probe. After incubation, the probe is run on a gel to detect any degradation from nuclease.

1. DEPC-treated Water - DEPC destroys enzymatic activity by modifying -NH^₂, -SH and -OH groups in RNases and other proteins. DEPC treatment is a very effective way to treat solutions that will contact RNA. Ambion's DEPC-treated water is autoclaved both before and after packaging to ensure sterility and complete inactivation of DEPC.

2. Nuclease-free Water (not DEPC-treated) - Ambion also offers nuclease-free water that is not DEPC-treated. Ambion's Nuclease-free Water is ideal for applications that are reported to be acutely sensitive to residual DEPC e.g., oocyte injection and other in vivo translation applications.

3. RT-PCR Grade Water - Ambion's RT-PCR grade water is tested for prokaryotic as well as eukaryotic genomic DNA contamination using a sensitive end-point PCR assay based on detection of rRNA genes. Prokaryotic DNA contamination is assessed by performing PCR with 16S rRNA primers, and eukaryotic DNA contamination is assessed by performing PCR with 18S rRNA primers. Each lot is also tested for nuclease contamination. This product is ideal for use in any PCR or RT-PCR application.

Bulk and Custom Orders
All of Ambion's water products can be packaged into larger custom sizes to fit your needs. Contact us at custom@ambion.com for more information.

Inactivate RNases in Solution DEPC treatment of solutions that come in contact with RNA can be time-consuming, possibly hazardous, and only eliminates RNases present at the time of treatment. Some solutions (e.g., primary amine containing compounds such as Tris) cannot be treated with DEPC at all. The RNAsecure™ Reagent eliminates these problems. RNAsecure is a unique nonenzymatic reagent that will irreversibly inactivate RNases in solution. Unlike DEPC, RNAsecure can be used with virtually any solution and does not require post-treatment autoclaving. The inactivation process can be repeated at any time to protect against introduced contaminants. RNAsecure does not interfere with downstream procedures, such as RT-PCR and in vitro transcription, and is also compatible with Tris and other solutions that cannot be treated with DEPC. The RNAsecure™ Resuspension Solution contains the same active ingredients as the RNAsecure Reagent, but is supplied at working concentration for direct resuspension of RNA pellets.

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