Protection against solar UV radiations in organisms includes production of secondary metabolites such as pigments that can absorb UV and visible light. In this study, vioA gene coding for tryptophan 2-monooxygenase involved in the biosynthetic pathway of violacein-like purple violet pigment (PVP) was cloned and sequenced from an Antarctic bacterium Janthinobacterium sp. Ant5-2. A non-pigmented vioA mutant strain was obtained following mini-Tn10 transposon mutagenesis that produced a lesser amount of extrapolymeric substances (EPS) and exhibited a compromised survival to freeze-thaw cycles at 4˚C. Survival of vioA mutant strain during exponential and stationary growth phase was significantly reduced when exposed to UVB (320 nm) and UVC (254 nm) (dose range: 0-300 J/m²) light. Decreased viability of the mutant strain was noticed at 4˚C upon nutrient deprivation and exposure to UV light. The pigment production was augmented in surviving cells following increased doses of both UVB and UVC. Interestingly, at higher doses i.e. 100 and 300 J/m², pigmented wild-type strain showed better survival to harmful UVC than UVB. This could be attributed to the pigment structure, which has absorption maxima in the visible (575 nm) as well as in the UVC (270 nm) range. In conclusion, this study defines the photoprotective role of the PVP in Janthinobacterium sp. Ant5-2 against UV radiation using single gene mutation. Perhaps the photoprotective role of PVP in this bacterium is one of the key adaptive features that define their survival in Antarctic extreme conditions, especially during austral summer months.
INTRODUCTION
The high energy photons in solar UV radiation are considered to be the most damaging component to the biological macromolec...
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...x, which is involved in quorum sensing mediated biofilm formation (Morohoshi et al., 2010). Therefore, it is likely that loss of vioA has affected the biofilm formation in Ant5-2. Moreover, colony morphology demonstrated that PVP had substantial effect on the structural organization of colony biofilms (Fig. 4). The mechanisms whereby pigment production control colony morphology and EPS production is likely to be a complex issue yet to be determined (Dietrich et al., 2008).
Until recently, the potential role of pigments as secondary metabolites modulating the cellular physiology of microorganisms in extreme environments has been neglected (Hernandez & Newman, 2001). This study provides an evidence for the role of PVP as a secondary metabolite in UV resistance and suggests its functions of primary importance in Ant5-2 residing in Antarctic extreme conditions.
The greater overall rate of absorbance change in all chloroplast samples (Figure 1) confirms role of chloroplasts’ in photosynthesis. However, the use of the supernatant sample as a negative control was expected to yield no activity, which was shown to be untrue (Figure 1) and is contributed to the contamination of the supernatant sample with chloroplast. The fragile envelope of the chloroplasts can be eas...
Biofilms are made up of a sessile, heterogeneous consortium of microbial cells that are irreversibly attached to a substratum or interface or to each other.(16) These microflora become embedded in a self-secreted complex exopolysaccharides (16,17)containing dead microorganisms, and inorganic materials derived from the supply water.
Up until the early 1960s, the people of that generation grew up believe that exposure to the sun was healthy and could be used as potential treatments for ailments like acne, for example. The doctors of the early 20th century even promoted the use of the sun’s ultraviolet rays (UV rays) as a treatment for certain strains of tuberculosis. Little did they know the long run consequences of prolonged exposure to the now-labeled ...
[7] Rothschild, Lynn J. “The Influence of UV Radiation on Protistan Evolution.” Journal of Eukaryotic Microbiology (1999), Issue 46 no. 5 pg. 548-555.
The photosynthetic organisms use their internal makeup to carry out the process of photosynthesis. Their makeup is different from that of organisms such as animals. Plant and algae cells contain chloroplasts where photosynthesis takes place. The light reactions of photosynthesis drive the transformation of solar energy into ATP. The chloroplasts of plants contain pigment molecules (chlorophyll) which are responsible for capturing the light from the
Scientists have performed many different tests and studies to learn more about high exposure to UV. Close observation of cells have shown that sunlight, natural or artificial, can cause mutations or DNA damage in cells. This can lead to further damage which will then be passed down through generations. Another study scientists perform is on animals. Scientist will expose your typical lab animals to UV rays, and this test typically results in skin cancer on the animal. These studies have been performed with UVA, UVB, and UVC, and they have all proven
The absorption of light in the form of photons through the thylakoid membrane into the lumen is the first step of photosynthesis. This photons absorbed through the lumen go through photochemical reduction in which they are absorbed into pigments such as chlor...
In the case of temperatures the cultures were incubated at each determined temperature. For the UV radiation, cells were exposed to UV light for 10 seconds and then grown in 30oC. For the EtBr treatment, 50ul of EtBr was added to the growth medium and cells were incubated at 30oC. In the case of sunlight exposure, cells were exposed to sunlight directly and grown at room temperature
Radiation has many benefits for humans, but too much of any type of radiation can be harmful. For example, the sun gives off infrared radiation, or heat, as well as visible light, another type of electromagnetic radiation. These ...
Photosynthesis is a widely studied topic among the world of science due to its importance for life and its many uses. Photosynthetic pigments reflect and absorb different wavelengths of visible light based off their polarity. In this experiment, we studied photosynthetic pigments, first, by determining polarity and then, by measuring the amount of light of a given wavelength that a pigment absorbs. We used two methods in this experiment, chromatography and spectrophotometry. For the first portion of our experiment we determined the distance each pigment migrated, their R_f values, and their polarity. Our predications based off polarity, lead to our hypothesis
Biofilms are formed by a six step process. First is a reversible process, when an organic monolayer(made of polysaccharides or glycoproteins) absorbs to the surface, altering the chemical and physical properties of the surface. This makes the surface more conditioned and increase the chance that planktonic bacteria will attach. Secondly, also a reversible step, is when the free-floating or planktonic bacteria encounter the conditioned surface, and some attachment of the bacteria may occur. The third step is when the bacteria is left attached too long, then an irreversible attachment occurs. F...
Fluorescence was first discovered in Aequorea victoria, which synthesizes aquorin, a chemiluminescent protein. It is a luciferase that catalyses coelenterazine oxidation through a calcium dependent reaction to emit blue light and green fluorescence under UV light. Soon after, it was cloned and GFP was expressed in bacteria (Williams, Slatko and McCarrey, 2007).
The energy extracted today by the burning of coal and petroleum products represents sunlight energy captured and stored by photosynthesis almost 200 million years ago. A third very interesting group of bacteria synthesize sugars, not by using sunlight’s energy, but by extracting energy from inorganic chemical compounds; In a (d) deep sea vent, chemoautotrophs, such as these (e) thermophilic bacteria, capture energy from inorganic compounds to produce organic compounds.
The Importance of Photosynthesis and What it Does for Life According to scientists, life is “the condition that distinguishes animals and plants from inorganic matter, including the capacity for growth, reproduction, functional activity, and continual change preceding death, also the way of life of a human being or animal. ”("Life,”) In order for one to have life, one must have the nine characteristics to be considered a living thing. These nine characteristics are: all living things are made up of cells, living things are able to reproduce, living things use energy, maintain homeostasis, respond and adapt to the environment, grow and develop, have a life span, evolve over time, and are interdependent. All of the nine characteristics have one thing in common, something that is needed for all living things to work, even if they do not know it.
Increases in temperature can decrease the efficiency of photosynthesis; however the extent of this impact may be determine on the species' dependency on light.