Ultraviolet (UV) radiation is known to inhibit cell growth and induce gene damage (1). For these reasons, UV radiation is used as a method to sterilize surgical instruments because it kills the bacteria present and disrupts bacterial reproduction (2).
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Would bacteria grow when not exposed to UV light?
Jan 27, 2015 · In contrast with chlorination, which kills by destroying the bacterial cell membrane, UV treatment leaves the membrane intact but damages bacterial DNA to block replication.
Why does UV radiation cause death in vegetative cells but not endospores?
Jun 01, 2019 · It was well known that bacteria can reactivate after UV irradiation, so photoreactivation and dark repair of the donor cells after UV irradiation were investigated. From Fig. 3 , it can be seen that after 1 mJ/cm 2 UV disinfection (2-log inactivation) and subsequent 8 h of photoreactivation, percent photoreactivation reached more than 40%, and the cell number …
Which phase would have the best survival after exposure to UV?
Sep 07, 2015 · Sep 07, 2015. Ultraviolet (UV) radiation is known to inhibit cell growth and induce gene damage (1). For these reasons, UV radiation is used as a method to sterilize surgical instruments because it kills the bacteria present and disrupts bacterial reproduction (2).
How long does it take for a UV light to kill microbes?
Conclusion from day 1: cells were definitely damaged from only 5-10 minutes of UV light in the hood (we have normal hood UV lights that are built into …
What happens to bacterial cells when they are exposed to UV light?
Can bacteria survive UV radiation?
Can cells survive UV light?
How does UV radiation affect the bacterial genome?
How does bacteria protect themselves from UV light?
What would have happened if Bacillus would have produced spores before exposure to UV radiation?
Why is UV light lethal to living cells?
How does ultraviolet radiation disrupt the cell cycle?
How does melanin protect from UV damage?
Melanin protects the skin by shielding it from the sun. When the skin is exposed to the sun, melanin production increases, which is what produces a tan. It's the body's natural defense mechanism against sunburn.Oct 29, 2021
How does UV radiation affect the DNA and cell growth?
How does UV light damage the DNA strand?
What is the role of UV radiation in microbiology?
When were antibiotics invented?
Antibiotics have been widely used in medical industry, animal husbandry and aquaculture since the invention of penicillin in 1927. Although they have saved millions of people's life, the unsupervised abuse of antibiotics arose the emerging of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs), leading to a serious worldwide health problem.
Can bacteria survive UV light?
It was reported that UV light was directly absorbed by the nucleic acids, causing damage to the DNA of the microorganisms ( Lee et al., 2015 ). Moreover, it was suggested that UV light directly penetrated the cell membrane to be absorbed by the nucleobases comprising DNA and RNA ( Dodd, 2012, Quek and Hu, 2008 ). That means, UV light can penetrate the relatively UV-transparent structures as cell walls and cell members, and directly damage the DNA of the microorganisms and thereby resulting in the formation of pyrimidine dimers ( Lee et al., 2015 ). In that condition, it is highly possible that UV disinfection may impress the ability of conjugative plasmid expression in bacteria at nucleic acid level. So, although the bacteria can survive from the UV ir radiation, it might lose some of its transfer ability.
What is thymine dimer?
Thymine Dimers - bonding between adjacent thymine bases in the DNA.
What is a control plate?
The control was the side of plate that was NOT exposed to UV light.
Does UV light affect E. coli?
With increased time exposure to UV light, E. Coli formed less colonies.
Is there the same amount of growth on the control side as on the exposed side?
No. There was the same amount of growth on the control side as was on the exposed side.
Can a cell be killed to prevent it from replicating?
They can kill that cell or disable it to prevent it from replicating.
What color should a pglo plate be?
The bacteria on the (+) pGLO LB/amp/ara plate should appear whitish when exposed to normal, room lighting, but fluoresce bright green upon exposure to the long-wave UV light.
How to test for ampicillin resistance?
The best test would be to take some of the bacteria growing on the LB plate and streak them on an LB/amp plate. If the bacteria are viable on the LB/amp plate, then they are resistant to ampicillin. If no bacterial colonies survive, then they were not ampicillin resistant (they were ampicillin sensitive).
What is GFP in biology?
study of biological processes, observation of cell movement, use of GFP as a visual marker. To genetically transform an entire organism, you must insert the new gene(s) into every cell in the organism.
Where are transformed cells found?
The transformed cells are found on the LB/amp and LB/amp/ara plates. Genetically transformed cells have taken up the pGLO plasmid which expresses the ampicillin resistance gene—these cells can survive on the plates which contain ampicillin.
What is the goal of genetic transformation?
Recall that the goal of genetic transformation is to change an organism's traits (phenotype). Before any change in the phenotype of an organism can be detected, a thorough examination of its usual (pre-transformation) phenotype must be made.
What color are bacteria?
Bacteria are a whitish color. Colony size is similar both before and after transformation.
How to genetically transform an entire organism?
To genetically transform an entire organism, you must insert the new gene (s) into every cell in the organism. Which organism is better suited for total genetic transformation-one composed of many cells, or one composed of a single cell?
What is the function of endospores?
spore photo-product is generated by UV light in endospores that functions in the enzymatic repair of damaged DNA during endospore germination.
Why aren't primers needed in vivo?
Why aren't they necessary in vivo? PCR needs two primers, each complementary to a different strand, because the primers define the region that will be amplified. In the first cycle, the double stranded DNA is heated, so that the hydrogen bonds holding the 2 strands together break, and the 2 strands fall apart.
Which is more resistant to UV light, endospores or vegetive cells?
Endospores are more resistant to UV light than vegetive cells
Why are primers not necessary for PCR?
in vivio occurs within a living organism.... primers aren't necessary because DNA replication uses RNA instead of primers... PCR occurs in a tube or in vitro.
What is the TDP of a cell?
Thermal death point (TDP) the lowest temperature at which a population of a target organism is killed in 10 minutes. Thermal death time (TDT) the shortest time required to kill a suspension of cells or spores under defined conditions at a given temperature.
What is the cell protection mechanism that removes dimmers and inserts in their place new pyrimidine molecules?
Cell protection against UV damage include the repair mechanisms, such as the SOS system, which enzymatically removes dimmers and inserts in their place new pyrimidine molecules
How does UV radiation affect living cells?
When DNA absorbs UV light, it causes the formation of pyrimidine dimers which form when a covalent bond forms between two adjacent thymine or cytosine molecules in a strand of DNA.