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
The Benzoic Acid Detection Kit provides a rapid, simple, sensitive, and reliable test suitable for screening of Benzoic Acid concentration.
Benzoic Acid is a white solid that is an extensively used preservative. Although this preservative prevents or delays nutritional losses due to microbiological, enzymatic or chemical changes of foods during its shelf life there is a suspicion that small amounts of benzene may be formed from benzoic acid in nonalcoholic beverages in the presence of ascorbic acid. Benzoic acid and ascorbic acid are food additives which must be declared on the food. Benzoic acid or E 210 is a preservative which also occurs naturally, for instance, in cranberries. A maximum amount of 150 mg/l benzoic acid may be added to non-alcoholic flavored beverages.
Highly Sensitive Assay to Screen for Benzoic Acid
Visual Readout (sample dependent: milk, red/pink)
Detection range of 1ppm to 1500ppm
Tube or Plate based options available
Compatible with the Nix Sensor or plate readers to obtain quantitative results.
The Norgen MiniSizer 50 bp DNA Ladder is prepared to ensure quality and batch-to-batch consistency. This Ladder contains fourteen discrete fragments ranging from 25 bp to 650 bp in 50 bp increments with double intensity reference bands at 200 bp and 400 bp. The MiniSizer is ideal for PCR product size confirmation.
Contents:
1mL of premixed DNA ladder (0.5µg/10µL) in loading buffer (10mM EDTA, 10% glycerol, 0.015% bromophenol blue, and 0.17% SDS).
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MiniSizer 50 bp DNA Ladder (Cat# 11200) – 100 loads
Ladder Properties:
• Fourteen discrete bands, ranging from 50 bp to 650 bp
• Higher intensity bands at 200 bp and 400 bp for easy reference
| Fragment | Size (bp) | Mass (ng) |
| 1 | 650 | 61 |
| 2 | 600 | 46 |
| 3 | 550 | 36 |
| 4 | 500 | 30 |
| 5 | 450 | 35 |
| 6 | 400 | 85 |
| 7 | 350 | 27 |
| 8 | 300 | 25 |
| 9 | 250 | 16 |
| 10 | 200 | 54 |
| 11 | 150 | 33 |
| 12 | 100 | 21 |
| 13 | 50 | 17 |
| 14 | 25 | 14 |
Recommended Use:
Mix thoroughly. For best results, load 10µL of DNA ladder per well. For precise mass determination with a densitometer, stain gel after electrophoresis using 0.5µg/mL ethidium bromide for 30-40 minutes. The table above shows the size and mass for each band based on 10µL ladder per well.
Storage:
Stable at room temperature. For longer term storage, -20°C is recommended.
This ladder was standardized using 10µL of DNA per lane on a 0.8 cm thick, 13 x 15 cm, 1.0% agarose gel run in TAE buffer.