Melanoma is the deadliest form of skin cancer, arising from malignant transformation of pigment-producing melanocytes. The primary risk factor for melanoma and other skin cancers is DNA damage resulting from unprotected solar ultraviolet radiation (UVR). If incorrectly repaired, this damage can result in incorporation of mutations that cause aberrant cell...
The effects of ultraviolet (UV) irradiation on photosynthesis and
various partial reactions involving the individual photoreactions of
photosynthesis were examined. These reactions included photo-reduction in adapted green algae, Hill reaction, cyclic photophosphorylation,
the 520 nm absorbance change and variable-yield fluorescence.
The reactions were measured in spinach chloroplasts and
isolated chloroplasts...
This study sought a better understanding of the mechanism of
the near-ultraviolet inhibition of microsclerotia and pigment formation
in the fungus Verticillium albo-atrum Reinke & Berth. by observing
changes which occur in certain major biochemical components:
lipids, chitin, RNA, DNA, protein carbohydrates, and pigment.
The most important finding was that...
The ozone present in the atmosphere filters incident solar
ultraviolet (UV) radiation such that only the longer wavelengths of
the total UV spectrum emitted by the sun reach the earth's surface.
Atmospheric increases in nitrogen oxides and chlorofluoromethanes
represent a threat to the existence of this protective screen. As
the...
Reduction of stratospheric ozone caused by human
perturbation with halocarbon compounds and the consequent
increase in mid-wavelength ultraviolet radiation (UV-B
radiation. 290-320 nm) reaching the earth's surface could
have deleterious ecological effects on marine primary
producers. Unialgal and mixed cultures of Thalassiosira
pseudonana and Thalassiosira weisflogii were exposed to
three...
Artificial substrates colonized by diatoms from Yaquina Estuary, Oregon, were exposed to solar visible radiation and three levels of ultraviolet radiation (UV-B, 290-320 nm). Flow-through microcosms were constructed inside a glasshouse to serve as chambers for the artificial substrates. The artificial substrates were sampled during three spring/summer experiments. Chlorophyll a...
Two strains of Escherichia coli were studied to determine the effect of constitutive expression of the SOS DNA damage repair response on the activity of ribonucleotide reductase. Activity of the reductase and cellular deoxynucleoside triphosphate (dNTP) pools were both determined before and after exposure of the cells to ultraviolet radiation....
Prostate cancer is the most commonly diagnosed cancer in men, but rates around the world vary greatly. Americans have the highest incidence rates in the world, 4 to 5 times those of Spain. The hypothesis of this thesis was that vitamin D metabolism is a factor in prostate cancer development...