bis-PEG23-endo-BCN

The series of DNA Size Selection Kits (Magnetic Beads) were developed for DNA size selection using magnetic beads. A total of 11 kits are available, with different selection ranges spanning from 50 bp to over 10 kb. The kits provide a simple and quick approach for the enrichment of a specific range of DNA fragments. The kit workflow allows double-sided or single-sided size selection for specific size cutoffs.

Gel images of different ranges of size selection. Sheared human genomic DNA was used as input.

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DNA size selection is a selective capture of DNA fragments of a specific range of size for next-generation sequencing (NGS) library preparations, PCR, ChIP assay, DNA ligations, endonuclease digestions, adapter removal, and other genomics and molecular biology applications. DNA size selection is preferred after NGS library prep in most of the cases. The NGS library preparation is related to the quality of the sequencing data. Precise NGS library size selection can increase sequencing efficiency, improve data quality, and reduce costs.

There are two types of sequencing technologies: short-read sequencing and long-read sequencing. Short-read sequencing uses DNA libraries that contain small insert DNA fragments of similar sizes, usually several hundred base pairs. The sequencing efficiency can be improved if the DNA size selection is in the right range. Cat.# 20104S and 20104L are the best kits for NGS library size selection of illumina paired-end 100 (PE100) sequencing with 100-200 bp library inserts; Cat.# 20105S and 20105L are the best kits for NGS library size selection of illumina paired-end 150 (PE150) sequencing with 150-300 bp library inserts; and Cat.# 20106S and 20106L are the best kits for NGS library size selection of illumina paired-end 300 (PE300) sequencing with 300-600 bp library inserts.

Long-read sequencing uses a large DNA fragment as input and makes very long reads. Usually, library size selection is preferred to remove smaller fragments. Cat.# 20110S and 20110L are the best kits for long-read sequencing size selection with DNA sizes >5 kb, and Cat.# 20111S and 20111L are the best kits for long-read sequencing size selection with DNA sizes >10 kb.

The magnetic beads technology uses paramagnetic particles, also known as SPRI (Solid Phase Reversible Immobilization) beads, to bind DNA reversibly and selectively. DNA fragments can be size-selected and purified by changing the properties of the magnetic beads or SPRI beads. The magnetic beads can easily separate the beads-binding DNA from the contaminants and unwanted components in the samples. The samples after DNA size selection are free of contaminants such as buffer components, enzymes, proteins, salts, dNTPs, primers, and adapters. Our proprietary magnetic beads reagents improve yield, selectivity, and reproducibility.

Specific DNA fragments at a certain length range can be purified simply using magnetic separation with different beads components, avoiding tedious and time-consuming gel extraction and column-based purification. The magnetic beads method is popular for common DNA size selection, including library size selection. The first beads-binding step, referred to as the right-side clean-up, removes large DNA fragments. The large DNA fragments are bound to the beads and are discarded. The desired DNA fragments in the supernatant are transferred to a new well, and new beads are added to the supernatant for the second beads-binding, referred to as the left-side clean-up. The double-size selected DNA fragments are eluted after ethanol rinsing.

DNA size selection with dual clean-ups.

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A single clean-up is needed for DNA size selection with large fragments. In this case, only the large DNA fragments are bound to the beads. The selected larger DNA fragments are eluted after ethanol rinsing.

DNA size selection with single clean-up for >5 kb and >10 kb DNA.

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Features of DNA size selection and library size selection

• • • High specificity and high recovery of size selection
    • 11 selection ranges are available, including 5 ranges for NGS library size selection
      • • 50-100 bp
        • 100-200 bp
        • 200-500 bp
        • 250-350 bp: ideal for illumina PE100 sequencing
        • 300-450 bp: ideal for illumina PE150 sequencing
        • 450-750 bp: ideal for illumina PE300 sequencing
        • 500-1000 bp
        • 1-3 kb
        • 1-5 kb
        • >5 kb: ideal for long-read sequencing
        • >10 kb: ideal for long-read sequencing
    • Fast and simple
      • • 20-min protocol
        • No gel purification required
        • No columns required
        • No centrifugation required
    • Efficient removal of contaminants and unwanted components

Description

Escherichia coli is one of many species of bacteria living in the lower intestines of mammals, known as gut flora. When located in the large intestine, it assists with waste processing, vitamin K production, and food absorption. Discovered in 1885 by Theodor Escherich, a German pediatrician and bacteriologist, E. coli are abundant: the number of individual E. coli bacteria in the faeces that a human defecates in one day averages between 100 billion and 10 trillion. However, the bacteria are not confined to the environment, and specimens have also been located, for example, on the edge of hot springs. The E. coli strain O157:H7 is one of hundreds of strains of the bacterium that causes illness in humans.

E. coli are unable to sporulate. Thus, treatments which kill all active bacteria, such as pasteurization or simple boiling, are effective for their eradication, without requiring the more rigorous sterilization which also deactivates spores. As a result of their adaptation to mammalian intestines, E. coli grow best in vivo or at the higher temperatures characteristic of such an environment, rather than the cooler temperatures found in soil and other environments.

The enteric E. coli (EC) are divided on the basis of virulence properties into enterotoxigenic (ETEC – causative agent of diarrhea in humans, pigs, sheep, goats, cattle, dogs, and horses), enteropathogenic (EPEC – causative agent of diarrhea in humans, rabbits, dogs, cats and horses); enteroinvasive (EIEC – found only in humans), verotoxigenic (VTEC – found in pigs, cattle, dogs and cats); enterohaemorrhagic (EHEC – found in humans, cattle, and goats, attacking porcine strains that colonize the gut in a manner similar to human EPEC strains) and enteroaggregative E. coli (EAggEC – found only in humans).

E. coli O157:H7 was first recognized as a pathogen as a result of an outbreak of unusual gastrointestinal illness in 1982. The outbreak was traced to contaminated hamburgers, and the illness was similar to other incidents in the United States and Japan. The etiologic agent of the illness was identified as a rare O157:H7 serotype of Escherichia coli in 1983. This serotype had only been isolated once before, from a sick patient in 1975.

Exceptional value for money
Rapid detection of all clinically relevant subtypes
Positive copy number standard curve for quantification
Highly specific detection profile
High priming efficiency
Broad dynamic detection range (>6 logs)
Sensitive to < 100 copies of target Accurate controls to confirm findings

DBCO-PEG4-PABA is an analog of DBCO-Acid with PEG linker and a 4-Aminobenzoic acid (PABA) group. The DBCO groups is commonly used for copper-free Click Chemistry reactions due to its strain promoted high energy. The hydrophilic PEG chain allows for increased water solubility. Reagent grade, for research use only.

DBCO-PEG4-PABA is an analog of DBCO-Acid with PEG linker and a 4-Aminobenzoic acid (PABA) group. The DBCO groups is commonly used for copper-free Click Chemistry reactions due to its strain promoted high energy. The hydrophilic PEG chain allows for increased water solubility. Reagent grade, for research use only.