Question: Why Are Some Bacteria More Resistant To UV Light Than Others?

Why are endospores more resistant to UV light than are vegetative bacteria?

What are 2 reasons why endospores more resistant to UV light than are vegetative cells.

1) The DNA of endospores is protected by small, acid-soluble proteins that bind to DNA and alter its conformation, thereby protecting it from photochemical damage..

What type of bacteria can survive UV light?

Deinococcus radiodurans is an extremophilic bacterium and one of the most radiation-resistant organisms known.

Can boiling water for 20 minutes kill endospores?

Different microorganisms will respond differently to high temperatures, with some (e.g., endospore-formers such as C. botulinum) being more heat tolerant. … However, boiling is less effective at killing endospores; some endospores are able to survive up to 20 hours of boiling.

Why are endospores not affected by ultraviolet light?

Why are endospores more resistant to UV light than vegetative cells? – The DNA of endospores is protected by small, acid-soluble proteins that bind to DNA and alter its conformation, thereby protecting it from photochemical damage.

What is the effect of UV light on bacteria?

Ultraviolet light inactivates microorganisms by forming pyrimidine dimers in RNA and DNA, which can interfere with transcription and replication (Goosen and Moolenaar, 2008; Cutler and Zimmerman, 2011).

What wavelength of UV is most germicidal?

260 to 265 nmThe most effective germicidal wavelength occurs at a peak of 260 to 265 nm at which DNA absorbs UV the most (5, 6), and LEDs can be designed to produce these specific wavelengths.

Which UV light is best for sterilization?

UV-C lightWhat Type of UV Light is Best? Most UV sterilization devices use UV-C light as the source of their disinfecting power. UV-C light is an effective solution for sterilization, which is why it is the most widely used light type.

Can UV light kill endospores?

Bacterial endospores, of the type by Bacillus and Clostridium species, are known to be highly resistant to various forms of radiation and other physical and chemical agents. High-intensity ultraviolet light, however, was suspected to overcome such resistance and to kill spores efficiently.

Why is bacillus resistant to UV light?

Dormant spores of the various Bacillus species, including B. … The novel UV photochemistry of spore DNA is largely due to its saturation with a group of small, acid-soluble proteins (SASP), which are unique to spores and whose binding alters the DNA conformation and thus its photochemistry.

Which bacteria is most resistant to UV light?

Deinococcus radiodurans was the most resistant bacterium to both types of radiation, with a D37 value of 4.0 × 104 μWs cm−2 to UV light and 300 krads to gamma radiation.

Can bacteria become resistant to UV light?

Contrary to the hypothesis that subsurface bacteria should be sensitive to UV light, the organisms studied exhibited resistance levels as efficient as those of surface bacteria. A total of 31% of the aerobic subsurface isolates were UV resistant, compared with 26% of the surface soil bacteria that were tested.

Why is sterilization by UV light not always effective?

2 reasons sterilization by ultraviolet radiation is not always effective: … Why is ultraviolet radiation not used for deep-seated tumors? -it is not short enough, and therefore does not penitrate into deeper tissues. – it is absorbed by skin cells and causes sunburn.

Does ultraviolet light kill E coli?

Water passing through the UV system is blasted with bacteria-killing UV rays. … UV systems are easy to maintain and highly effective at killing not only E. coli and other bacteria but a range of other viruses and waterborne parasites.

Do hospitals use UV light?

The use of ultraviolet light systems is becoming more widely used in healthcare facilities for disinfecting patient and operating rooms. … UV-C is also used in night time cleaning of laboratories and meat packing facilities. Another term used for UV-C disinfection is Ultraviolet Germicidal Irradiation (UVGI).

Does UV light damage food?

Scientists have found that simple and inexpensive ultraviolet light technology can kill food-borne pathogens on the surface of certain fruits such as apples and pears. … The light did not affect the chemical or the physical quality of the fruit used during the study.