Ethidium bromide

Source: Wikipedia, the free encyclopedia.
Not to be confused with
Ethyl bromide
.
Ethidium bromide
Names
Preferred IUPAC name
3,8-Diamino-5-ethyl-6-phenylphenanthridin-5-ium bromide
Other names
  • 2,7-Diamino-10-ethyl-6-phenylphenanthridinium bromide
  • 2,7-Diamino-10-ethyl-9-phenylphenanthridinium bromide
  • 3,8-Diamino-1-ethyl-6-phenylphenantridinium bromide
  • 5-Ethyl-6-phenyl-phenanthridine-3,8-diamine bromide
  • Ethidium bromide
  • Homidium bromide
  • EtBr
  • EthBr
Identifiers
3D model (
JSmol
)
3642536
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard
 100.013.622 Edit this at Wikidata
EC Number
  • 214-984-6
KEGG
RTECS number
  • SF7950000
UNII
UN number 2811
  • InChI=1S/C21H19N3.BrH/c1-2-24-20-13-16(23)9-11-18(20)17-10-8-15(22)12-19(17)21(24)14-6-4-3-5-7-14;/h3-13,23H,2,22H2,1H3;1H checkY
    Key: ZMMJGEGLRURXTF-UHFFFAOYSA-N checkY
  • InChI=1/C21H19N3.BrH/c1-2-24-20-13-16(23)9-11-18(20)17-10-8-15(22)12-19(17)21(24)14-6-4-3-5-7-14;/h3-13,23H,2,22H2,1H3;1H
    Key: ZMMJGEGLRURXTF-UHFFFAOYAD
  • CC[n+]1c2cc(N)ccc2c3ccc(N)cc3c1c4ccccc4.[Br-]
Properties
C21H20BrN3
Molar mass 394.294 g/mol
Appearance Purple-red solid
Melting point 260 to 262 °C (500 to 504 °F; 533 to 535 K)
~40 g/l
Pharmacology
QP51DX03 (WHO
)
Hazards[1]
GHS labelling:
GHS06: ToxicGHS08: Health hazard
Danger
H302, H330, H341
P201, P202, P260, P284, P301+P312, P304+P340+P310
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 4: Very short exposure could cause death or major residual injury. E.g. VX gasFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
4
1
0
Flash point > 100 °C (212 °F; 373 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

Ethidium bromide (or homidium bromide,

ultraviolet light, it will fluoresce with an orange colour, intensifying almost 20-fold after binding to DNA. Under the name homidium, it has been commonly used since the 1950s in veterinary medicine to treat trypanosomiasis in cattle.[5] The high incidence of antimicrobial resistance makes this treatment impractical in some areas, where the related isometamidium chloride is used instead. Despite its reputation as a mutagen, tests have shown it to have low mutagenicity without metabolic activation.[6][7]

Structure, chemistry, and fluorescence

Absorption spectrum of ethidium bromide

As with most

ultraviolet light. As a result of this excitation, EtBr emits orange light with wavelength 605 nm.[8][9]

Ethidium bromide's intense fluorescence after binding with DNA is probably not due to rigid stabilization of the

hydrophobic environment and away from the solvent, the ethidium cation is forced to shed any water molecules that were associated with it. As water is a highly efficient fluorescence quencher, the removal of these water molecules allows the ethidium to fluoresce.[citation needed
]

Applications

DNA sample separated using gel electrophoresis of nucleic acids and stained with ethidium bromide, which emits orange light after binding to DNA

Ethidium bromide is commonly used to detect

fluorescent images recorded as photographs. Where direct viewing is needed, the viewer's eyes and exposed skin should be protected. In the laboratory the intercalating properties have long been used to minimize chromosomal condensation when a culture is exposed to mitotic arresting agents during harvest. The resulting slide preparations permit a higher degree of resolution, and thus more confidence in determining structural integrity of chromosomes upon microscopic analysis.[citation needed
]

Ethidium bromide is also used during DNA fragment separation by agarose gel electrophoresis.[10] It is added to running buffer and binds by intercalating between DNA base pairs. When the agarose gel is illuminated using UV light, DNA bands become visible. Intercalation of EtBr can alter properties of the DNA molecule, such as charge, weight, conformation, and flexibility. Since the mobilities of DNA molecules through the agarose gel are measured relative to a molecular weight standard, the effects of EtBr can be critical to determining the sizes of molecules.[11]

Ethidium bromide has also been used extensively to reduce mitochondrial DNA copy number in proliferating cells.[12] The effect of EtBr on mitochondrial DNA is used in veterinary medicine to treat trypanosomiasis in cattle, as EtBr binds molecules of kinetoplastid DNA and changes their conformation to the Z-DNA form. This form inhibits replication of kinetoplastid DNA, which is lethal for trypanosomes.[13]

The chloride salt homidium chloride has the same applications.[3][4]

Ethidium bromide can be added to YPD media and used as an inhibitor for cell growth.[14]

The binding affinity of the cationic nanoparticles with DNA could be evaluated by competitive binding with ethidium bromide.[15][16]

Alternatives for gel

There are alternatives to ethidium bromide which are advertised as being less dangerous and having better performance.

MSDS for SYBR Safe reports an LD50 for rats of over 5 g/kg, which is higher than that of EtBr (1.5 g/kg). Many alternative dyes are suspended in DMSO, which has health implications of its own, including increased skin absorption of organic compounds.[19] Despite the performance advantage of using SYBR dyes instead of EtBr for staining purposes, many researchers still prefer EtBr since it is considerably less expensive.[citation needed
]

Possible carcinogenic activity

Ethidium bromide intercalated between two adenine–thymine base pairs. The intercalation is said by some [by whom?] to motivate a high mutagenicity of DNA.[6]

Most use of ethidium bromide in the laboratory (0.25–1 µg/ml) is below the LD50 dosage, making acute toxicity unlikely. Testing in humans and longer studies in a mammalian system would be required to fully understand the long-term risk ethidium bromide poses to lab workers, but it is clear that ethidium bromide can cause mutations in mammalian and bacterial cells.[22]

Handling and disposal

Ethidium bromide is not regulated as hazardous waste at low concentrations,

Safety Data Sheet (SDS).[citation needed
]

The disposal of laboratory ethidium bromide remains a controversial subject.

ion exchange resin is recommended.[27] Various commercial products are available for this use.[28]

Drug resistance

Trypanosomes in the Gibe River Valley in southwest Ethiopia showed universal resistance between July 1989 and February 1993.[29] This likely indicates a permanent loss of function in this area against the tested target, T. congolense isolated from Boran cattle.[29]

See also

References

  1. ^ "GESTIS-Stoffdatenbank". gestis.dguv.de (in German). Retrieved 22 November 2021.
  2. ^ "Homidium bromide". PubChem. NCBI, NLM, US NIH. Retrieved 2020-09-08. CID 14710 from PubChem
  3. ^
    S2CID 27564786
    .
  4. ^ a b "Homidium chloride". PubChem. NCBI, NLM, US NIH. Retrieved 2021-03-14. CID 11765 from PubChem
  5. PMID 7676909
    .
  6. ^ a b Lowe, Derek (2016-04-18). "The Myth of Ethidium Bromide". In the Pipeline. Retrieved 2019-02-28.
  7. ^ "Ethidium Bromide: Swap or Not | UCSB Sustainability". sustainability.ucsb.edu. Retrieved 2023-02-08.
  8. ISBN 978-0-470-40753-0
    .
  9. ^ "Application Note: Ethidium Bromide" (PDF). Retrieved 6 April 2014.
  10. PMID 16511967
    .
  11. S2CID 10593378
    .
  12. PMID 12409452
    .
  13. PMID 21187912
    .
  14. PMID 16467477
    .
  15. PMID 30327464
    .
  16. PMID 889813
    .
  17. S2CID 27423672
    .
  18. ^ Madden D. "Safer stains for DNA". Retrieved 2009-12-08.
  19. ^
    PMID 10029672
    .
  20. PMID 11377248
    .
  21. ^ "Novel Juice testing report" (PDF). Newmarket Scientific.
  22. ^ National Toxicology Program (2005-08-15). "Executive Summary Ethidium Bromide: Evidence for Possible Carcinogenic Activity" (PDF). Retrieved 2009-09-30.
  23. ^ "Executive Summary Ethidium Bromide" (PDF). National Toxicology Program. 2005-08-15. Retrieved 2009-09-30.
  24. PMID 8073504
    .
  25. ISBN 1-56670-567-3
    .
  26. PMID 3605608
    .
  27. PMID 3238760
    .
  28. ^ "Ethidium Bromide Disposal". Archived from the original on 2015-04-15. Retrieved 2006-10-03.
  29. ^
    S2CID 23878484
    .

External links
Retrieved from "https://en.wikipedia.org/w/index.php?title=Ethidium_bromide&oldid=1209908375"