How does light (UV radiation) effect bacterial growth?
How does light (uv radiation) effect bacterial growth? By causing change in the DNA structure. (UV) light, exerts its mutagenic effect by exciting electrons in molecules. Theexcitation of electrons in DNA molecules often results in the formation of extrabonds between adjacent pyrimidines (specifically thymine) in DNA.
How does gamma irradiation affect microbes?
Gamma radiation light does its damage at the cellular level, and its devastation can affect the organisms as complicated as human being or as simple as microbe (Ruscitto Cynthia, 2012). There are the following factors which affect the microbial growth with the help of gamma irradiation.
What are the effects of microwave radiation on living organisms?
Microwave radiation has thermal and non-thermal effects upon living organisms. ... ... Both effects are dependent on the extent of the radiation absorption, on the dielectric constant and on the electrical conductivity of the target material.
Do bacteria need light or dark to grow?
Light Phototrophic bacteria require light for the growth. However, most of the bacteria can grow well in darkness. The presence of ultraviolet rays and radiation can reduce bacterial growth. Photochromogenic mycobacterium is a unique species that produce pigments only at the presence of light.
How does microwave radiation affect living things?
How does a microwave affect microbes?
What is the role of Staphylococcus epidermidis in the skin?
What is AST in microbiology?
What is microwave radiation?
What is the frequency of microwaves?
Do microwaves destroy microorganisms?
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How does radiation affect growth of microorganisms?
Ultraviolet light destroys harmful microbes such as bacteria, yeast, molds, viruses and algae, and ultraviolet radiation is less toxic to cave dwellers such as birds, reptiles and visitors. So ultraviolet radiation can be a way to control microorganisms or reduce their numbers.
What is the effect of radiation on bacteria?
One of the most important properties of irradiation is inactivation of microorganisms, especially pathogens. Gram-negative pathogen bacteria are very sensitive to radiation. As expected bacterial spores are more resistant to ionizing radiation than vegetative cells are.
How does radiation completely destroy microbial life?
Ionizing Radiation Simply put, this radiation causes damage to the genetic material - the DNA or the RNA - of the organism's cell. If the DNA or RNA of a microorganism is damaged, the cell will die. In other words, radiation damages the hard drive of a bacterium, causing it to shut down for good.
How does UV radiation affect bacterial growth?
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).
Can bacteria be exposed to radiation?
Extreme radiation–resistant microorganisms can survive doses of ionizing radiation far greater than are present in the natural environment. Radiation resistance is believed to be an incidental adaptation to desiccation resistance, as both hazards cause similar cellular damage.
Is bacteria resistant to radiation?
The bacterium Deinococcus radiodurans shows remarkable resistance to a range of damage caused by ionizing radiation, desiccation, UV radiation, oxidizing agents, and electrophilic mutagens.
What type of radiation is best for destroying microbes throughout food?
Ionization radiations are used to ensure food safety and quality. This irradiation process uses ions of beta or gamma rays to inactivate or destroy the food spoilage pests, microorganisms and their toxins without significantly increasing the temperature of the treated product.
How does radiation sterilize food?
How irradiation works. When food is irradiated, it absorbs energy. This absorbed energy kills the bacteria that can cause food poisoning in a similar way that heat energy kills bacteria when food is cooked. They can also delay fruit ripening and help stop vegetables from sprouting.
What are the radiation methods of microorganism control?
Radiation in various forms, from high-energy radiation to sunlight, can be used to kill microbes or inhibit their growth. Ionizing radiation includes X-rays, gamma rays, and high-energy electron beams.
How UV and gamma rays can disrupt the bacterial growth?
Ionizing radiation (e.g. x-rays, gamma radiation) carries enough energy to remove electrons from molecules in a cell. When electrons are removed from molecules, free radicals are formed that damage the cell leading to DNA damage, mutations, and cell death.
How do bacteria survive UV radiation?
Bacteria, especially extremophiles inhabiting harsh environments permanently exposed to damaging solar radiation, have evolved different strategies to cope with UV stress, mainly relying on efficient DNA repair mechanisms and/or active defense against UV-induced oxidative stress, and consequently need to tightly ...
How does UV light damage bacterial DNA?
UVA (and also UVB) radiation cause indirect damage to DNA via absorption of photons by non-DNA chromophores. This generates reactive oxygen species like singlet oxygen or hydrogen peroxide that oxidize the DNA bases causing mutations.
How does radiation affect the bacterial membrane?
(e) In bacterial cells, where the DNA is attached to the cytoplasmic membrane, radiation damage to the membrane may have a marked effect on reproductive survival by influencing the repair of radiation damage to the DNA.
How do bacteria eat radiation?
What Reguera discovered in 2011 was that Geobacter makes protein filaments on one side of its cells that act like wires to "zap" uranium. That does two things. For one, the jolt triggers chemical reactions that give the bacteria energy.
What is the likely effect from radiation that leads to the death of a bacterial cell?
Radiation and electrons bombarded by radiation move haphazardly inside the cell, resulting in damage to the various molecules forming the cell. Chromosomal DNA inside the cell nucleus can also be damaged.
Can bacteria survive gamma radiation?
Even 2 (4.8%) isolates were found to be survive at 9 KGy (Table 2). Gamma irradiation doses equal or greater than 9 KGy were sufficient for the total elimination of the growth and multiplication of bacterial isolates.
Effect of Microwave Radiation on Bacteria, Fungi and Some Growth ...
In this study, an experiment was conducted to describe the effects of using microwaves and chemical fertilization (isolated and combined) on the number of bacteria and fungi in the soil and on the growth of cowpea plants Vigna unguiculata L. Several times of exposure to microwave radiation (0, 25, 30, 35, 40, 45 s) and several concentrations of chemical fertilizer NPK (0, 0.9, 1.8 g 3 kg−1 ...
EFFECT OF RADIATION ON MICROORGANISMS - World Scientific
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The Effect of Microwaves on Food - Doctors Beyond Medicine
DBM COMMENTS. After having studied the section on EMFs and their effects on the body, combined with the knowledge that the body is, by weight over 60% water (this varies based upon factors such as age, health, weight and sex) – we leave you to decide whether or not microwaves which essentially will alter the structure of the molecular structure of food.
Does Microwave Kill Bacteria (Do they Really Sterilize)
Conclusion. To wrap it all up, microwaves do not kill bacteria but what actually does kill bacteria is heat. The safest route to take is making sure that after defrosting food in a microwave oven or using styrofoam, make sure that you cook it thoroughly by allowing it to stay longer and cook more evenly or using a regular oven or convection oven to cook the food right through.
Do microwaves kill germs? They may kill viruses on a sponge
Microwave ovens produce radio-frequency waves that cause the water molecules in an object to vibrate. This vibration causes friction, which allows the object to heat up to a temperature that can kill germs. That's why microwaves are sometimes used to disinfect items such as a household sponge, as they are a hotbed for viruses and bacteria. However, research has found mixed results on whether a ...
How does UV radiation affect bacteria?
Effect of UV Radiation on Bacterial Growth. To Study the effect of UV exposure on the growth of bacterial cells. Mutations are a heritable change in the base sequence of DNA. Such mutations can be neutral or beneficial to an organism, but most are actually harmful because the mutation will often result in the loss of an important cellular function.
What is the effect of ionizing radiation on DNA?
Ionizing radiation (x-ray, gamma radiation) has the potential to remove electrons from molecules in a cell. These electrons called free radicals which damage most other molecules in a cell, such as DNA or RNA, by oxidizing them.
What are the two types of electromagnetic radiation that are mutagenic?
Again there are two forms of electromagnetic radiation that are mutagenic; ionizing radiation and nonionizing radiation.
How long does it take to get LB nutrient agar plates exposed to UV light?
3) The plate is exposed to direct UV light for time intervals of 5, 10, 15, 30 minutes, by covering half of the plate with the glass plate.
What temperature should exposure plates be incubated at?
4) After exposure plates are incubated overnight at 37o C.
Abstract
X-ray irradiation was evaluated for improving microbial safety and the quality of flue-cured tobacco during aging. Tobacco samples were irradiated at doses of 0, 1, 2, 3 and 5 kGy and stored for 12 months under normal storage conditions or in a high-humidity (RH>70%) room.
1. Introduction
The flue-cured tobacco leaves is one of the most important type of tobacco in the world. Cured but unaged tobacco is unsuitable for cigarette products because it has a sharp, disagreeable odor and an undesirable aroma; it also produces harsh, irritating smoke.
2. Materials and methods
The tobacco used for treatments was an all-lamina flue-cured tobacco blend. Unaged flue-cured tobacco (grade C2F) was collected from Tianchang International Tobacco Co., Ltd. (Xuchang, Henan Province, China) in 2012, and the samples (1 kg) were placed into polyethylene bags.
3. Results and discussion
Changes were first assessed regarding the microbial population on the tobacco samples ( Table 1 ). The purpose was to examine the efficacy of X-ray irradiation on the decontamination of mold in flue-cured tobacco. The initial population of total aerobic bacteria for the control samples was 4.61 log CFU/g.
4. Conclusion
The adaptation of X-ray irradiation as a deinfestation treatment for cigarette beetle has been reported by Imai et al. (2006). It was found that 0.1 kGy prevents reproduction in Lasioderma serricorne (F.) (Coleoptera: Anobiidae) adults.
Acknowledgments
This work was supported by the Special Fund for Agroscientific Research in the Public Interest ( 201103007 ).
What are the factors that affect the growth of microbial cells?
There are the following factors which affect the microbial growth with the help of gamma irradiation. Short wavelength of gamma rays can damage chemical bonds in the microbial cells' DNA. (author) Primary Subject. RADIATION, THERMAL, AND OTHER ENVIRONMENTAL POLLUTANT EFFECTS ON LIVING ORGANISMS AND BIOLOGICAL MATERIALS (S63) Source.
What is gamma radiation?
[en] Gamma irradiation may be defined as the very high-energy ionizing radiation photons that emit by radioactive nuclei. Gamma irradiation refers to the product of radioactive atoms. Depending upon the ratio of neutrons and protons within its nucleus, an isotope of a particular element may be stable or unstable. A gamma ray is a packet of electromagnetic energy (photon) emitted by the nucleus of some radio nuclides following radioactive decay. Gamma rays are highly efficient in killing the microorganisms and do not leave residues or have adequate energy to impart radioactivity for their adverse effect on the microbial population in the environment (Todar Kenneth, 2009). The range of gamma rays which affect the microbial growth in the environment is 10 20 -10 24 (wavelength in hertz) <10 -12 (wavelength in meter) (Space Today Online, 2004). Although gamma radiation from the sun light plays a significant role in our environment and positively affects nearly everything living, negative consequences of overexposure have been well documented in scientific literature. Skin cancer, cataracts, premature skin aging and immune system suppression all have been linked to excessive amounts of gamma energy. Gamma radiation light does its damage at the cellular level, and its devastation can affect the organisms as complicated as human being or as simple as microbe (Ruscitto Cynthia, 2012). There are the following factors which affect the microbial growth with the help of gamma irradiation. Short wavelength of gamma rays can damage chemical bonds in the microbial cells' DNA. (author)
How efficient are gamma rays?
Gamma rays are highly efficient in killing the microorganisms and do not leave residues or have adequate energy to impart radioactivity for their adverse effect on the microbial population in the environment (Todar Kenneth, 2009). The range of gamma rays which affect the microbial growth in the environment is 10 20 -10 24 (wavelength in hertz) ...
Is gamma radiation harmful to the environment?
Although gamma radiation from the sun light plays a significant role in our environment and positively affects nearly everything living, negative consequences of overexposure have been well documented in scientific literature.
What are the factors that affect microbe growth?
Environmental Factors affecting Microbial Growth. Apart from nutritional components growth of the microbes are also dependent on several environmental factors. These factors play an important role in understanding the growth pattern of a microbe. Apart from that, it is important to understand these factors especially in an industrial set up ...
How much carbon dioxide does a bacteria need to grow?
Most of the bacteria require a small amount of carbon dioxide for growth. This carbon dioxide is usually provided by the environment or it can be produced by the bacteria due to cellular metabolism. Organisms such as Brucella abortus require a high level of Carbon dioxide (5-10%) for growth.
What is the role of the cell wall in osmotic pressure?
Bacterial cell wall plays an important role in withstanding the osmo tic pressure. Plasmolysis (osmotic withdrawal of water leading to shrinkage of protoplasm) can occur if the bacteria are suddenly transferred into a hypertonic solution. On the other hand, if the bacteria are transferred into a concentrated solution palsmoptysis (excessive osmotic imbibitions of water leading to swelling and rupture of the cell) can occur.
Why is water important for bacteria?
Water is an essential component for the growth of the bacteria. 80% of the bacterial cell is made up of water. Therefore, the presence of a free water molecule is important for the optimum growth of the microorganism. Apart from that desiccation or drying has a severe effect on microbes.
What is the temperature of a bacteria?
4. Temperature. It is an essential environmental factor that can influence the growth of the organisms. Most of the pathogens grow at 37 0 C (body temperature).
Why is pH important for microbes?
May bacteria are able to produce several organic acids which reduce the pH of the medium and also restrict the growth of other bacteria. Apart from that some media constituents can be affected by low pH.
Which group of bacteria can grow both under the presence and absence of oxygen?
Facultative Anaerobes: These are the group of bacteria that can grow both under the presence and absence of oxygen. Most of the pathogenic bacteria are facultative anaerobes. Eg: E. coli. Anaerobes: These are also known as obligate anaerobes as they can’t grow in the presence of oxygen at the environment.
What factors affect the growth of microorganisms?
The environmental and nutritional factors may favour or restrict the growth of microorganisms. Some microbes survive in extreme conditions or the changing environment, while few can not thrive. The bacterial growth factors decide the increase in cell size and mass of the bacterial cell. In this post, we will discuss bacterial growth factors like ...
What are the factors that affect bacteria growth?
Bacterial growth factors primarily include temperature, pH, salt concentration, light source, nutritional and gaseous requirement etc. Microorganisms live in diverse natural habitats such as the atmosphere, hydrosphere and lithosphere. The environmental and nutritional factors may favour or restrict the growth of microorganisms.
How does osmotic pressure affect bacteria?
Osmotic pressure and salt concentration of the solution can influence bacterial growth. The bacterial cell wall gives a mechanical strength that allows the bacteria to withstand alternations in the osmotic pressure. Osmophilic bacteria require high osmotic pressure.
What bacteria grow best at 80 degrees Celsius?
Thermophiles or hyperthermophiles represent another group, which grow best at a temperature of 80 degrees Celsius or above. Thermophilic bacteria like Archaebacteria, Thermus aquaticus predominate in volcanic and ocean vents.
Which bacteria can tolerate oxygen?
Aerotolerant anaerobes include Lactobacillus sp, Enterococcus faecalis etc., that can use oxygen but can tolerate its presence. Microaerophiles include Campylobacter sp e cies that require oxygen but at low concentration and sensitive to toxic forms of oxygen.
What happens when bacteria are subjected to hypertonic solution?
When the bacterial cell is subjected to the hypertonic solution, it may cause osmotic water removal, resulting in plasmolysis or osmotic shrinkage of the protoplasm.
How do microorganisms adjust to pH?
Microorganisms can adjust to changes in the environment pH by maintaining an internal pH that is near neutrality. Some bacteria also synthesize shock proteins in response to pH. The pH of the medium also determines which pathway of metabolism will come into action.
How does microwave radiation affect living things?
Microwave radiation has thermal and non-thermal effects upon living organisms. ... ... Both effects are dependent on the extent of the radiation absorption, on the dielectric constant and on the electrical conductivity of the target material.
How does a microwave affect microbes?
The nature and extent of the effect depend on the frequency of microwaves and the total energy absorbed by the microorganisms.
What is the role of Staphylococcus epidermidis in the skin?
Staphylococcus epidermidis, a major constituent of the normal microflora on healthy human skin, acts as a barrier against colonization of potentially pathogenic microbes and against overgrowth of already present opportunistic pathogens.
What is AST in microbiology?
Infection diagnosis and antibiotic susceptibility testing (AST) are pertinent clinical microbiology practices that are in dire need of improvement, due to the inadequacy of current standards in early detection of bacterial response to antibiotics and affordability of contemporarily used methods. This paper presents a novel way to conduct AST which hybridizes disk diffusion AST with microwave resonators for rapid, contactless, and non-invasive sensing and monitoring. In this research, the effect of antibiotic (erythromycin) concentrations on test bacterium, Escherichia coli (E. coli) cultured on solid agar medium (MH agar), are monitored through employing a microwave split-ring resonator. A one-port microwave resonator operating at a 1.76 GHz resonant frequency, featuring a 5 mm 2 sensitive sensing region, was designed and optimized to perform this. Upon introducing uninhibited growth of the bacteria, the sensor measured 0.005 dB/hr, with a maximum change of 0.07 dB over the course of 15 hrs. The amplitude change decreased to negligible values to signify inhibited growth of the bacteria at higher concentrations of antibiotics, such as a change of 0.005 dB in resonant amplitude variation while using 45 µg of antibiotic. Moreover, this sensor demonstrated decisive results of antibiotic susceptibility in under 6 hours and shows great promise to expand automation to the intricate AST workflow in clinical settings, while providing rapid, sensitive, and non-invasive detection capabilities.
What is microwave radiation?
Microwaves are non-ionizing electrom agnetic waves with frequencies betw een . and . GHz. Both humans and microorganisms living on the human body are exposed to significant. doses of microwave radi ation in everyday life. Whether and how microwave radiation c ould.
What is the frequency of microwaves?
Microwaves are non-ionizing electromagnetic waves with frequencies between 0.3 and 300 GHz. Both humans and microorganisms living on the human body are exposed to significant doses of microwave radiation in everyday life. Whether and how microwave radiation could influence the viability and growth of microorganisms is the subject ...
Do microwaves destroy microorganisms?
Low energy, low frequency microwaves enhance the growth of microorganisms, whereas high energy, high frequency microwaves destroy the microorganisms. However, neither the effects of a wide spectrum of frequencies nor the effects of a wide range of absorbed energies have been investigated.
