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Rajasekhar, E., G. Jaffer Mohiddin, M. Srinivasulu, V. Rangaswamy e R. Jeevan Kumar. "Effect of ionizing radiation on soil bacteria, fungi and germination of red gram seeds (Cajanus cajan L.)". South Asian Journal of Experimental Biology 3, n.º 1 (10 de março de 2013): 24–30. http://dx.doi.org/10.38150/sajeb.3(1).p24-30.
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Effect of ionizing radiation on survival of bacteria, fungi and red gram seed (Cajanus cajan L.) germination was assessed in laterite soil in the laboratory. The mercury vapor lamp (l = 400 nmâ€700 nm), sodium vapor lamp (l =589.3 nm ) and ultra violet (l = 400 nm †10 nm) radiations were exposed to the laterite soils for 20, 40, 60 and 80 min and their effect on survival of bacterial, fungal colonies and seed germination were enumerated. Sodium vapor was found to be very effective in inhibiting the bacterial and fungal populations. Ultra violet radiation was efficient in reducing the survival of the microbial densities than mercury vapor lamp. In the exposed soil, the germination of seeds in terms of percentage, the stem length (SL) and root length (RL) of seeds were calculated at 7th day of incubation. The laterite soil was shown significant stimulation in the germination of seed at 40 min exposure with ultra violet radiation. Results obtained in the present study indicate that the energy captivated by molecules was prominent at lower radiation and shorter exposure time enhanced the proliferation of bacterial cells and red gram seed germination.
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Patel, Priya, Hiteshi Patel, Dhara Vekariya, Chinmayi Joshi, Pooja Patel, Steven Muskal e Vijay Kothari. "Sonic Stimulation and Low Power Microwave Radiation Can Modulate Bacterial Virulence Towards Caenorhabditis elegans". Anti-Infective Agents 17, n.º 2 (5 de julho de 2019): 150–62. http://dx.doi.org/10.2174/2211352516666181102150049.
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<P>Background: In view of the global threat of antimicrobial resistance, novel alternative approaches to deal with infectious bacteria are warranted, in addition to the conventional invasive therapeutic approaches. Objective: This study aimed at investigating whether exposure to sonic stimulation or microwave radiation can affect virulence of pathogenic bacteria toward the model nematode host Caenorhabditis elegans. Methods: Caenorhabditis elegans worms infected with different pathogenic bacteria were subjected to sonic treatment to investigate whether such sound treatment can exert any therapeutic effect on the infected worms. Virulence of microwave exposed bacteria was also assessed using this nematode host. Results: Sound corresponding to 400 Hz, and the divine sound ‘Om’ conferred protective effect on C. elegans in face of bacterial infection, particularly that caused by Serratia marcescens or Staphylococcus aureus. The observed effect seemed to occur due to influence of sound on bacteria, and not on the worm. Additionally, effect of microwave exposure on bacterial virulence was also investigated, wherein microwave exposure could reduce virulence of S. aureus towards C. elegans. Conclusion: Sonic stimulation/ microwave exposure was demonstrated to be capable of modulating bacterial virulence.</P>
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ITO, Hitoshi. "Effect of radiation decontamination on drug-resistant bacteria". FOOD IRRADIATION, JAPAN 41, n.º 1-2 (2006): 9–13. http://dx.doi.org/10.5986/jrafi.41.9.
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Lin, Tao, Bo Cai e Wei Chen. "Limnoithona sinensis as refuge for bacteria: protection from UV radiation and chlorine disinfection in drinking water treatment". Canadian Journal of Microbiology 60, n.º 11 (novembro de 2014): 745–52. http://dx.doi.org/10.1139/cjm-2014-0347.
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In this study, we tested the potential of Limnoithona sinensis to provide its attached bacteria refuge against disinfection. The experimental results indicated that in water devoid of zooplankton, both UV radiation and chlorine disinfection significantly decreased the viability of free-living bacteria. In the presence of L. sinensis, however, the attached bacteria could survive and rapidly recover from disinfection. This demonstrated that L. sinensis provided protection from external damage to various aquatic bacteria that were attached to its body. The surviving bacteria remained on L. sinensis after disinfection exposure, which enabled a rapid increase in the bacterial population followed by their subsequent release into the surrounding water. Compared with UV radiation, chlorine disinfection was more effective in terms of inactivating attached bacteria. Both UV radiation and chlorine disinfection had little effect in terms of preventing the spread of undesirable bacteria, due to the incomplete inactivation of the bacteria associated with L. sinensis.
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Hughes, Kevin A. "Effect of Antarctic solar radiation on sewage bacteria viability". Water Research 39, n.º 11 (junho de 2005): 2237–44. http://dx.doi.org/10.1016/j.watres.2005.04.011.
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Bauza-Kaszewska, Justyna, Krzysztof Skowron, Zbigniew Paluszak, Zbigniew Dobrzański e Mścisław Śrutek. "Effect of Microwave Radiation on Microorganisms in Fish Meals". Annals of Animal Science 14, n.º 3 (29 de julho de 2014): 623–36. http://dx.doi.org/10.2478/aoas-2014-0020.
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AbstractThis study was aimed at testing the effect of microwave radiation on survival of E. coli, Salmonella Enteritidis, Enterococcus spp. and Clostridium spores in two kinds of fish meals. The material used in the study consisted of samples of two kinds of fish meal – salmon and cod. In the experiment samples of both kinds of fish meals were inoculated with suspensions of tested bacteria and spores of Clostridum sporogenes. After inoculation the material was exposed to microwave radiation with a frequency of 2.45 ghz and microwave energy power of 0, 100, 180, 300, 450, 600 and 700 w, respectively, for 2.5 min for bacteria and 11 minutes for spores. then the reisolated microorganisms were counted and theoretical lethal doses of radiation were determined. among the studied vegetative forms of bacteria, the largest decreases in the numbers at the same radiation dose were observed in the rods of E. coli, whereas the smallest in enterococci. spores of Clostridium sporogenes showed a considerably higher resistance to the effect of that factor. the power of dose resulting in the complete inactivation of the studied bacteria should be about 430 kJ×g–1, and in the case of spores – 1 900 kJ×g–1.
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Alonso-S�ez, Laura, Josep M. Gasol, Thomas Lefort, Julia Hofer e Ruben Sommaruga. "Effect of Natural Sunlight on Bacterial Activity and Differential Sensitivity of Natural Bacterioplankton Groups in Northwestern Mediterranean Coastal Waters". Applied and Environmental Microbiology 72, n.º 9 (setembro de 2006): 5806–13. http://dx.doi.org/10.1128/aem.00597-06.
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ABSTRACT We studied the effects of natural sunlight on heterotrophic marine bacterioplankton in short-term experiments. We used a single-cell level approach involving flow cytometry combined with physiological probes and microautoradiography to determine sunlight effects on the activity and integrity of the cells. After 4 h of sunlight exposure, most bacterial cells maintained membrane integrity and viability as assessed by the simultaneous staining with propidium iodide and SYBR green I. In contrast, a significant inhibition of heterotrophic bacterial activity was detected, measured by 5-cyano-2,3 ditolyl tetrazolium chloride reduction and leucine incorporation. We applied microautoradiography combined with catalyzed reporter deposition-fluorescence in situ hybridization to test the sensitivity of the different bacterial groups naturally occurring in the Northwestern Mediterranean to sunlight. Members of the Gammaproteobacteria and Bacteroidetes groups appeared to be highly resistant to solar radiation, with small changes in activity after exposure. On the contrary, Alphaproteobacteria bacteria were more sensitive to radiation as measured by the cell-specific incorporation of labeled amino acids, leucine, and ATP. Within Alphaproteobacteria, bacteria belonging to the Roseobacter group showed higher resistance than members of the SAR11 cluster. The activity of Roseobacter was stimulated by exposure to photosynthetic available radiation compared to the dark treatment. Our results suggest that UV radiation can significantly affect the in situ single-cell activity of bacterioplankton and that naturally dominating phylogenetic bacterial groups have different sensitivity to natural levels of incident solar radiation.
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Dion, Paule, Raymond Charbonneau e Chantal Thibault. "Effect of ionizing dose rate on the radioresistance of some food pathogenic bacteria". Canadian Journal of Microbiology 40, n.º 5 (1 de maio de 1994): 369–74. http://dx.doi.org/10.1139/m94-060.
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Food pathogenic bacteria including Listeria monocytogenes (1A1 and ATCC 19111), Staphylococcus aureus (GD13 and ATCC 13565), Escherichia coli 0157:H7 (ATCC 35150), Salmonella typhimurium, Yersinia enterocolitica, Vibrio parahaemolyticus, and Campylobacter jejuni were exposed to various rates of ionizing radiation (0.78, 2.6, and 22 kGy/h) emitted by three different 60Co irradiators. D10 values (D10 is the radiation dose required to eliminate 90% of a bacterial population (one logarithmic cycle reduction)) were calculated for the various strains and growth conditions tested. A covariance analysis of these results revealed that the dose rates studied had no significant influence on the radiosensitivity of these bacteria. At all dose rates, the bacteria were more radiosensitive when irradiated in a saline solution (0.85% NaCl) than in a chicken breast meat suspension. The growth phase of the bacterial population had a variable influence on its radioresistance. For L. monocytogenes 1A1, Staphylococcus aureus ATCC 13565, E. coli 0157:H7, Y. enterocolitica, and V. parahaemolyticus, radioresistance was not significantly different in the exponential and stationary phases. Populations of L. monocytogenes ATCC 19111 and Staphylococcus aureus GD13 were significantly more resistant in the stationary phase (D10 = 0.23 and 0.12 kGy, respectively) than in the exponential phase (D10 = 0.17 and 0.09 kGy, respectively). Among the pathogenic bacteria investigated in this study, the most radioresistant was L. monocytogenes (D10 = 0.16–0.38 kGy, Gram-positive bacilli) and the most radiosensitive was V. parahaemolyticus (D10 = 0.03–0.04 kGy, halophilic Gram-negative bacilli).Key words: ionization, food pathogenic bacteria, dose rate effect, radioresistance.
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AL.Bayatti, Khalid K. "The Effect of Ionizing Radiation on Microorganism in some spices". Iraqi Journal of Veterinary Medicine 33, n.º 1 (30 de junho de 2009): 149–54. http://dx.doi.org/10.30539/iraqijvm.v33i1.728.
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The present study was undertaken to evaluate the use of ionizing radiation in decontaminating thetotal microbial burden of Capsicum peppers (Capsium annuum), Caraway (Carum carvi), and Clove(Dianthus caryphyllus). The spices were irradiated in polyethylene bags with 5KGy and 10KGy ofgamma radiation from Co-60 irradiator. Total number of bacteria and molds survived per gram ofspices after irradiation were calculated. Results showed that 5KGy gamma radiation reduced the totalnumber of bacteria by 95-98% and the number of molds and yeast by 62.8-98.2%, while 10KGyreduced the total number of bacteria by 95.5-99.9% and the number of the molds and yeast by 67-99.7%. These percentages are accepted within the maximum permissible microbial counts for humanconsumption except mold and yeast counts in caraway which its number was still more than themaximum permissible count for human consumption, and the doses used in these experiments have nosignificant changes on the sensory quality of the spices.
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Lu, Winston I., e Dominic P. Lu. "The Bacteriostatic and Bactericidal Effects of Radiation from Dental and Medical X-Rays". Acupuncture & Electro-Therapeutics Research 45, n.º 1 (24 de agosto de 2020): 3–14. http://dx.doi.org/10.3727/036012920x15958782196790.
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The purpose of this research was to proce or disprove the widely held beliefs that X-ray radiation used in medical or dental applications may affect the normal oral flora, and may also have effects on the micro-organisms existing in the oral cavity of every person. Such beliefs might be due to the common knowledge that radiation therapy has been utilized for the long time in the cancer patients to destroy the cancerous cells, and that radiation are also widely used in agriculture to prolong the shelf life of the farm products by destroying the decay-causing microorganisms existing in the agricultural products such as meats, produce, etc. Since very few research has been conducted in this concerned area, and not much pertinent information in the scientific literature could be found in this regard, a research experiment was set up to find out if these common beliefs have any merits. The research experiment involved selecting BDORT(By-digital O-Ring Test) positive dishes to incubate human saliva collected from a volunteer patient. Once dish served as control which was not subjected X-ray irradiation. Other dishes were subjected X-ray irradiation with various doses of irradiation strength at various time interval such as 1, 3, 5, 7, and 9 seconds to find out if any significant change taken place in the bacteria colonies. The bacterial colonies in the irradiated dishes then compared with that of the control dish so as to draw a conclusion if radiation for medical and dental X-ray machines would actually have any bactericidal or/and bacteriostatic effects on the oral micro-organisms flora. Finally, dishes were brought to a local hospital Radiology Department to use high dose of irradaition (used for cancer therapy) on the dishes to find out to what extent if such a high dose X-ray irradiation emitted from therapeutic cancer therapy machine would affect the number of bacterial colonies in the dishes as when compared with when dishes were under low doses of X-ray irradiation from dental or medical diagnostic X-ray machines. During the experiment, dishes, when irradiated, were sent to a certified medical technologist in the hospital laboratory to count the number of the bacterial colonies, and each change in the bacterial colony number were recorded in to data for biostatic analysis. The data were compared with BDORT negativity scores collected each time before and after dishes were irradiated, thus to find out if any corresponding confirmity between traditional laboratory findings and the score changes from BDORT findings. The results of this experiment revealed the fact that radiation from regular diagnostic X-ray machines possess little effect on bacteria, and that they have little effect on both cells and bacteria present in the human body. Neverthless, dramatically increasing the high radiation dosages does have potential to both inhibit and destroy bacteria. Therefore,using irradiation techniques to inhibit bacterial growth is only useful in agriculture practices, since tens of thousands of irradaiation dosages are necessary for bacteria inhibition. in human, over 500 RADs (radiation absorption dose) is lethal. Therefore, bacterial inhibition could not be practical in humans since it requires tens of thousands of RADs to be useful in the aspect.
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Kudryasheva, N. S., e T. V. Rozhko. "Effect of low-dose ionizing radiation on luminous marine bacteria: radiation hormesis and toxicity". Journal of Environmental Radioactivity 142 (abril de 2015): 68–77. http://dx.doi.org/10.1016/j.jenvrad.2015.01.012.
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TURGIS, M., J. HAN, J. BORSA e M. LACROIX. "Combined Effect of Natural Essential Oils, Modified Atmosphere Packaging, and Gamma Radiation on the Microbial Growth on Ground Beef". Journal of Food Protection 71, n.º 6 (1 de junho de 2008): 1237–43. http://dx.doi.org/10.4315/0362-028x-71.6.1237.
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Selected Chinese cinnamon, Spanish oregano, and mustard essential oils (EOs) were used in combination with irradiation to evaluate their ability to eliminate pathogenic bacteria and extend the shelf life of medium-fat-content ground beef (23% fat). Shelf life was defined as the time when the total bacterial count reached 107 CFU/g. The shelf life of ground beef was determined for 28 days at 4°C after treatment with EOs. The concentrations of EOs were predetermined such that sensory properties of cooked meat were maintained: 0.025% Spanish oregano, 0.025% Chinese cinnamon, and 0.075% mustard. Ground beef samples containing EOs were then packaged under air or a modified atmosphere and irradiated at 1.5 kGy. Ground beef samples (10 g) were taken during the storage period for enumeration of total mesophilic aerobic bacteria, Escherichia coli, Salmonella, total coliforms, lactic acid bacteria, and Pseudomonas. Mustard EO was the most efficient for reducing the total mesophilic aerobic bacteria and eliminating pathogenic bacteria. Irradiation alone completely inhibited the growth of total mesophilic aerobic and pathogenic bacteria. The combination of irradiation and EOs was better for reducing lactic acid bacteria (mustard and cinnamon EOs) and Pseudomonas (oregano and mustard EOs). The best combined treatment for extending the shelf life of ground beef for up to 28 days was EO plus irradiation (1.5 kGy) and modified atmosphere packaging.
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Gupta, Sakshi Satyendranarayan. "U.V radiation effect on growth and survival of bacteria Staphylococcus aureus". Asian Journal of Pharmaceutical Analysis 11, n.º 1 (2021): 27–28. http://dx.doi.org/10.5958/2231-5675.2021.00005.3.
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Al-Hakami, Samer M., Amjad B. Khalil, Tahar Laoui e Muataz Ali Atieh. "Fast Disinfection ofEscherichia coliBacteria Using Carbon Nanotubes Interaction with Microwave Radiation". Bioinorganic Chemistry and Applications 2013 (2013): 1–9. http://dx.doi.org/10.1155/2013/458943.
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Water disinfection has attracted the attention of scientists worldwide due to water scarcity. The most significant challenges are determining how to achieve proper disinfection without producing harmful byproducts obtained usually using conventional chemical disinfectants and developing new point-of-use methods for the removal and inactivation of waterborne pathogens. The removal of contaminants and reuse of the treated water would provide significant reductions in cost, time, liabilities, and labour to the industry and result in improved environmental stewardship. The present study demonstrates a new approach for the removal ofEscherichia coli(E. coli) from water using as-produced and modified/functionalized carbon nanotubes (CNTs) with 1-octadecanol groups (C18) under the effect of microwave irradiation. Scanning/transmission electron microscopy, thermogravimetric analysis, and FTIR spectroscopy were used to characterise the morphological/structural and thermal properties of CNTs. The 1-octadecanol (C18) functional group was attached to the surface of CNTs via Fischer esterification. The produced CNTs were tested for their efficiency in destroying the pathogenic bacteria (E. coli) in water with and without the effect of microwave radiation. A low removal rate (3–5%) of (E. coli) bacteria was obtained when CNTs alone were used, indicating that CNTs did not cause bacterial cellular death. When combined with microwave radiation, the unmodified CNTs were able to remove up to 98% of bacteria from water, while a higher removal of bacteria (up to 100%) was achieved when CNTs-C18was used under the same conditions.
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Brook, Itzhak, Richard I. Walker e Thomas J. MacVittie. "Effect of radiation dose on the recovery of aerobic and anaerobic bacteria from mice". Canadian Journal of Microbiology 32, n.º 9 (1 de setembro de 1986): 719–22. http://dx.doi.org/10.1139/m86-130.
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The presence of aerobic and anaerobic bacteria in the blood, spleen, and liver was investigated in mice that were exposed to 7, 8, 9, or 10 Gy 60Co radiation. Microorganisms were detected more often in animals exposed to higher doses of radiation. The number of mice that were culture positive and the number of isolates in one site increased with increasing dose. Bacteria were recovered in mice killed at various times after radiation, in 3 of 100 mice exposed to 7 Gy, in 13 of 100 irradiated with 8 Gy, in 23 of 90 exposed to 9 Gy, and in 34 of 87 irradiated with 10 Gy. The predominant organisms recovered were Escherichia coli, anaerobic Gram-positive cocci, Proteus mirabilis, Staphylococcus aureus, and Bacteroides spp. Escherichia coli and anaerobes were more often isolated in animals exposed to 10 Gy, while S. aureus was more often recovered in those irradiated with 9 Gy. These data demonstrate a relationship between the dose of radiation and the rate of infection due to enteric aerobic and anaerobic bacteria.
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Kaya, A. Uğur, Selahaddin Güner, Marklen Ryskin, Azaria Stephano Lameck, Ana R. Benitez, Uri Shuali e Shlomo Nir. "Effect of Microwave Radiation on Regeneration of a Granulated Micelle–Clay Complex after Adsorption of Bacteria". Applied Sciences 10, n.º 7 (7 de abril de 2020): 2530. http://dx.doi.org/10.3390/app10072530.
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Granulated micelle–clay complexes including the organic cation octadecyltrimethylammonium (ODTMA) were shown to be efficient in removal of total bacteria count (TBC) from water. Microwave (MW) heating of granules to restore bacterial removal was investigated. Drying of granules by MW required 20-fold less energy than by conventional heating. When water content of granules approached 10%, or less, their heating period by MW had to be below 1 min, e.g., 30 s, and less, in order to avoid ignition and irreversible structural changes. Structural and thermal properties of MW heated samples were studied by FT-IR spectra and thermo gravimetric analyses (TGA). Inactivation of bacteria in water was more efficient by MW than by conventional oven, or by electric plate. For elimination of bacteria from water, MW heating was at least five-fold more efficient than by conventional heating. The results have established an adequate regeneration procedure by MW heating at durations depending on the remaining percentage of water associated with the granules. Tests of first and second regenerations by MW heating, and HCl washing of columns, were carried out. It was concluded that MW treatment may be chosen for optimal regeneration of the granulated micelle–clay complex as an efficient and low-cost procedure.
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Yahya, Esam, Ali M. Almashgab, Muhanad Abdullah Abdulsamad, Abdulmutalib Alabeed Allaq, Amaal Mohammed Alqadhi, Fatima M. Garatem e Sara S. Aljundi. "Evaluation the Effect of Microwave Radiation on Gram Positive and Negative Bacteria". Journal of Chemistry and Nutritional Biochemistry 2, n.º 1 (30 de abril de 2021): 39–45. http://dx.doi.org/10.48185/jcnb.v1i1.136.
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Using microwave oven nowadays has become necessary due to the need for speed in our daily activities. It is widely used in hating, thawing, and even cooking of food. It has been also used in sterilization and decontamination of food from microorganisms. This study aimed to evaluate thermal and non-thermal effect of a regular house holding microwave oven on Staphylococcus aureus and Escherichia coli. Bacterial suspension is exposed to microwave radiations in different strength and durations and compared to unexposed cultures. During microwave treatment, non-thermal effect is evaluated by putting the suspension crushed ice. The results indicate that the viability of both gram positive and negative was highly reduced with thermal effect of microwave radiations, leading to complete inactivation at three minutes. Non-thermal microwave radiations were also able to cause change in the microbial viability of both tested organisms on at least two-exposure occasion. The evaluation of antibiotic susceptibility before and after microwave radiations treatment indicate that antibiotic resistance was highly increased to tested antibiotics specially after three-minute exposure, except for Staphylococcus aureus to Amoxicillin, which became more sensitive. Microwave radiations reported to have a strong activity in eliminating the number of microbes but, it may have an important role in development of antibiotic resistance that should not be ignored.
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MOINI, SOHRAB, REZA TAHERGORABI, SEYED VALI HOSSEINI, MOHAMMAD RABBANI, ZOYA TAHERGORABI, XESÚS FEÁS e FEREIDOON AFLAKI. "Effect of Gamma Radiation on the Quality and Shelf Life of Refrigerated Rainbow Trout (Oncorhynchus mykiss) Fillets". Journal of Food Protection 72, n.º 7 (1 de julho de 2009): 1419–26. http://dx.doi.org/10.4315/0362-028x-72.7.1419.
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The effect of gamma radiation (0, 1, 3, and 5 kGy) on the shelf life of farmed rainbow trout (Oncorhynchus mykiss) fillets that were treated with sodium acetate and vacuum packaged and subsequently stored under refrigeration was studied by measuring microbiological, chemical, and organoleptic changes. Radiation affected populations of bacteria, namely, H2S-producing bacteria and Enterobacteriaceae (P < 0.05). Initial total viable counts of the control samples were ca. 4.41 log CFU/g, whereas the respective counts in samples irradiated at 1, 3, and 5 kGy were 3.08, 1.46, and ≤1 log CFU/g at day 1 of refrigerated storage. The maximum count of Enterobacteriaceae reached 2.29 and 1.45 log CFU/g at the end of storage for 1 and 3 kGy, respectively, but at a 5-kGy dose no growth of Enterobacteriaceae was observed. Of the biochemical indicators, thiobarbituric acid values for irradiated trout were higher than for nonirradiated fish (P < 0.05). Sensory evaluation (taste) showed a reasonable and good correlation with bacterial populations with storage time. The results revealed that radiation at a high dose (5 kGy) might induce lipid and protein oxidation, although the growth of microorganisms was inhibited. Therefore, radiation at a low dose (3 kGy) could be used to control the microbial and safety biochemical indices of O. mykiss for up to 4 weeks at refrigerator temperature without adverse effects on quality and acceptability.
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Elagin, Vadim, Anton Smirnov, Vladimir Yusupov, Alexey Kirillov, Nadezhda Ignatova, Olga Streltsova, Evgeniy Grebenkin e Vladislav Kamensky. "The bactericidal effect of continuous wave laser with strongly absorbing coating at the fiber tip". Journal of Innovative Optical Health Sciences 11, n.º 05 (setembro de 2018): 1850029. http://dx.doi.org/10.1142/s1793545818500293.
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The bactericidal effect of laser radiation with a quartz fiber-based transmission system with a strong absorption coating converter against bacteria associated with urological stones has been studied. Gram-negative rod Escherichia coli and the Gram-positive coccus Staphylococcus epidermidis, Staphylococcus aureus, Enterococcus faecalis and Enterococcus faecium were used in this study. Each bacterial species was treated by continuous-wave near infrared laser coupled with bare fiber tip or strongly absorption coating fiber tip. After treatment, the temperature of bacterial suspension was measured. In addition, the temperature distribution was analyzed. It has been shown that using laser with a strongly absorption coating fiber tip results in significant bactericidal effect. The decrease of the amount of E. coli and S. epidermidis was 100% after treatment with an output power of 6[Formula: see text]W of radiation at a wavelength of 0.97[Formula: see text][Formula: see text]m for 40[Formula: see text]s. Number of S. aureus and Ent. faecium colony-forming unit was reduced to 70% after same exposure. The peak temperature of bacterial suspension was [Formula: see text]C after treatment by laser with a strongly absorption coating fiber tip. Laser with a strongly absorption coating fiber tip provides large-scale hydrodynamic flows directed away from the fiber tip. The laser with a strongly absorption coating fiber tip has bactericidal effect. The main role is associated with the effect of high temperature, which, in the form of flow in a liquid medium, affects bacteria.
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Balasubramaniam, Arun, Prakoso Adi, Tra My Do Thi, Jen-Ho Yang, Asy Syifa Labibah e Chun-Ming Huang. "Skin Bacteria Mediate Glycerol Fermentation to Produce Electricity and Resist UV-B". Microorganisms 8, n.º 7 (21 de julho de 2020): 1092. http://dx.doi.org/10.3390/microorganisms8071092.
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Bacteria that use electron transport proteins in the membrane to produce electricity in the gut microbiome have been identified recently. However, the identification of electrogenic bacteria in the skin microbiome is almost completely unexplored. Using a ferric iron-based ferrozine assay, we have identified the skin Staphylococcus epidermidis (S. epidermidis) as an electrogenic bacterial strain. Glycerol fermentation was essential for the electricity production of S. epidermidis since the inhibition of fermentation by 5-methyl furfural (5-MF) significantly diminished the bacterial electricity measured by voltage changes in a microbial fuel cell (MFC). A small-scale chamber with both anode and cathode was fabricated in order to study the effect of ultraviolet-B (UV-B) on electricity production and bacterial resistance to UV-B. Although UV-B lowered bacterial electricity, a prolonged incubation of S. epidermidis in the presence of glycerol promoted fermentation and elicited higher electricity to suppress the effect of UV-B. Furthermore, the addition of glycerol into S. epidermidis enhanced bacterial resistance to UV-B. Electricity produced by human skin commensal bacteria may be used as a dynamic biomarker to reflect the UV radiation in real-time.
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Rozhko, Tatiana V., Olga V. Kolesnik, Gennadii A. Badun, Devard I. Stom e Nadezhda S. Kudryasheva. "Humic Substances Mitigate the Impact of Tritium on Luminous Marine Bacteria. Involvement of Reactive Oxygen Species". International Journal of Molecular Sciences 21, n.º 18 (16 de setembro de 2020): 6783. http://dx.doi.org/10.3390/ijms21186783.
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The paper studies the combined effects of beta-emitting radionuclide tritium and Humic Substances (HS) on the marine unicellular microorganism—luminous bacteria—under conditions of low-dose radiation exposures (<0.04 Gy). Tritium was used as a component of tritiated water. Bacterial luminescence intensity was considered as a tested physiological parameter. The bioluminescence response of the marine bacteria to tritium corresponded to the “hormesis” model: it included stages of bioluminescence inhibition and activation, as well as the absence of the effect. HS were shown to decrease the inhibition and activation effects of tritium, similar to those of americium-241, alpha-emitting radionuclide, studied earlier. Correlations between the bioluminescence intensity and the content of Reactive Oxygen Species (ROS) were found in the radioactive bacterial suspensions. The results demonstrate an important role of HS in natural processes in the regions of low radioactive contamination: HS can mitigate radiotoxic effects and adaptive response of microorganisms to low-dose radioactive exposures. The involvement of ROS in these processes was demonstrated.
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Rijal, G. K., e R. S. Fujioka. "Synergistic effect of solar radiation and solar heating to disinfect drinking water sources". Water Science and Technology 43, n.º 12 (1 de junho de 2001): 155–62. http://dx.doi.org/10.2166/wst.2001.0728.
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Waterborne diseases are still common in developing countries as drinking water sources are contaminated and feasible means to reliably treat and disinfect these waters are not available. Many of these developing countries are in the tropical regions of the world where sunlight is plentiful. The objective of this study was to evaluate the effectiveness of combining solar radiation and solar heating to disinfect contaminated water using a modified Family Sol*Saver System (FSP). The non-UV transmittable cover sheet of the former FSP system was replaced with an UV transmittable plastic cover sheet to enable more wavelengths of sunlight to treat the water. Disinfection efficiency of both systems was evaluated based on reduction of the natural populations of faecal coliform, E. coli, enterococci, C. perfringens, total heterotrophic bacteria, hydrogen sulphide producing bacteria and FRNA virus. The results showed that under sunny and partly sunny conditions, water was heated to critical temperature (60°C) in both the FSP systems inactivating more than 3 log (99.9%) of the concentrations of faecal coliform and E. coli to undetectable levels of <1 CFU/100mL within 2-5 h exposure to sunlight. However, under cloudy conditions, the two FSP systems did not reduce the concentrations of faecal indicator bacteria to levels of <1 CFU/100mL. Nonetheless, sufficient evidence was obtained to show that UV radiation of sunlight plus heat worked synergistically to enhance the inactivation of faecal indicator bacteria. The relative log removal of indicator microorganism in the FSP treated water was total heterotrophic bacteria < C. perfringens < F RNA virus < enterococci < E. coli < faecal coliform. In summary, time of exposure to heat and radiation effects of sunlight were important in disinfecting water by solar units. The data indicated that direct radiation of sunlight worked synergistically with solar heating of the water to disinfect the water. Thus, effective disinfection was observed even when the water temperature did not reach 60°C. Finally, the hydrogen sulphide test is a simple and reliable test that householders can use to determine whether their water had been sufficiently disinfected.
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Atsumi, Tatsuo, Eriko Fujimoto, Masakazu Furuta e Mikio Kato. "Effect of gamma-ray irradiation on Escherichia coli motility". Open Life Sciences 9, n.º 10 (1 de outubro de 2014): 909–14. http://dx.doi.org/10.2478/s11535-014-0332-z.
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AbstractThe effects of ionizing radiation on bacteria are generally evaluated from the dose-dependent survival ratio, which is determined by colony-forming ability and mutation rate. The mutagenic damage to cellular DNA induced by radiation has been extensively investigated; however, the effects of irradiation on the cellular machinery in situ remain unclear. In the present work, we irradiated Escherichia coli cells in liquid media with gamma rays from 60Co (in doses up to 8 kGy). The swimming speeds of the cells were measured using a microscope. We found that the swimming speed was unaltered in cells irradiated with a lethal dose of gamma rays. However, the fraction of motile cells decreased in a dose-dependent manner. Similar results were observed when protein synthesis was inhibited by treatment with kanamycin. Evaluation of bacterial swimming speed and the motile fraction after irradiation revealed that some E. coli cells without the potential of cell growth and division remained motile for several hours after irradiation.
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Hernandez, Edgardo A., Gustavo A. Ferreyra e Walter P. Mac Cormack. "Response of two Antarctic marine bacteria to different natural UV radiation doses and wavelengths". Antarctic Science 18, n.º 2 (junho de 2006): 205–12. http://dx.doi.org/10.1017/s0954102006000241.
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The aim of this work was to investigate the effect of different fractions of UVR on two Antarctic marine bacteria (Arthrobacter UVvi and FCB-related UVps strains) and to study the relationship between the bacterial viability and the UVB dose. Ten experiments exposing strains to natural solar radiation were conducted in Potter Cove, South Shetland Islands. The effect of different UVR wavelengths on viability was analysed by using cultures in quartz bottles covered with interferential filters. Six treatments were performed: DARK, PAR (with UVR shielded off), UVA360, UVA320, UVB305 and UVB280. In all UVR treatments, strains showed significant losses of viability under high and moderate irradiance and no differences were observed between UV treatments. Under high UVB dose (15.0 kJ m−2 received in only two hours), the effect of UVB treatments was significantly higher than that observed under UVA treatments. However, UVA caused a significant reduction on bacterial viability. Survival rates were negatively correlated with integrated UVB dose, FCB-related UVps being more sensitive than Arthobacter UVvi. The similar values observed in viability when the same dose was received in different time periods suggested that DNA repair mechanisms are not much effective in these strains. The different response to the UV wavelength ranges studied here suggests that changes in the spectral composition of natural radiation could differentially affect the components of Antarctic marine bacterial communities.
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Deller, Sigrid, Franz Mascher, Sabine Platzer, Franz Ferdinand Reinthaler e Egon Marth. "Effect of Solar Radiation on Survival of Indicator Bacteria in Bathing Waters". Central European Journal of Public Health 14, n.º 3 (1 de setembro de 2006): 133–37. http://dx.doi.org/10.21101/cejph.a3380.
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Тучина, Е. С., e В. В. Тучин. "Фототермическое действие инфракрасного (808 nm) лазерного излучения и наночастиц золота в различных модификациях на S. aureus". Журнал технической физики 128, n.º 6 (2020): 840. http://dx.doi.org/10.21883/os.2020.06.49418.49-20.
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The effect of infrared laser radiation (808 nm) of different fluence rates on the bacteria Staphylococcus aureus 209 P, incubated in solutions of gold nanocubes, nanorods and on glass substrates with fixed nanodiscs, was studied. Radiation with a power density of 60 mW/cm2 in combination with nanocubes caused the death of 50% of the bacterial population after 30 min of exposure, in combination with nanostructures - 56%. An increase in the temperature of suspended matter after irradiation was found of no more than 5-6 °C. Radiation with a power density of 400 mW/cm2 caused a pronounced inhibition of the viability of bacterial cells – by 81% after 30 min. Incubation of microorganism suspensions on the surface of glass substrate containing gold nanodiscs during irradiation (808 nm, 400 mW/cm2) resulted in 99% of bacterial cell death.
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Haque, Md Mansurul, MG Sorrowar e Harun Ur Rashid. "Effects of frozen storage, radiation and their combined Treatments on microorganisms of freshwater mola fish Amblypharyngodon mola". Journal of Bangladesh Academy of Sciences 37, n.º 1 (13 de julho de 2013): 21–31. http://dx.doi.org/10.3329/jbas.v37i1.15677.
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The study revealed that the total viable bacterial count, staphylococcal count, coliform count, faecal coliform count, Aeromonas count and total fungal counts varied from 8.8×107 to 1.27×108, 2.7×106 to 4.2×106, 9.0×104 to 1.03×105, 4.8×105 to 7.3×105, 2.7×105 to 5.0×105 and 1.6×103 to 3.5×103 cfu/gm, respectively. Seventy six bacterial strains were isolated and identified, where Staphylococcus aureus, Micrococcus varians, Aeromonas hydrophila, Klebsiella ozaenae, Bacillus subtilis, Escherichia coli, Bacillus megaterium, Klebsiella edwardsii, Pseudomonas aerugenosa and Micrococcus radiodurans were 16 (21.06%), 11 (14.47%), 9 (11.82%), 6 (7.89%), 6 (7.89%), 8 (10.53%), 6 (7.89%), 4 (5.26%), 7 (9.21%) and 3 ( 3.95% ), respectively. Total coliform, faecal coliform, Aeromonas bacteria and total fungi were found to be totally inactivated by the irradiation dose of 2.5 kGy onwards and total viable bacteria and staphylococcal bacteria were eliminated completely at the irradiation dose of 7.5 kGy. The bacterial counts were shown to be gradually decreased in all the samples from initial to final storage. The combined treatments were found more effective than that of the single treatment for reducing or eliminating the associated bacteria. The moisture contents of the studied fish were found nearly similar during initial and final storage periods and also at different radiation doses but the total protein contents decreased during final storage period and also at different radiation doses. DOI: http://dx.doi.org/10.3329/jbas.v37i1.15677 Journal of Bangladesh Academy of Sciences, Vol. 37, No. 1, 21-31, 2013
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Brook, Itzhak, e G. David Ledney. "Use of Selective Decontamination in the Prevention of Infection After Accidental Irradiation". Prehospital and Disaster Medicine 8, n.º 1 (março de 1993): 85–88. http://dx.doi.org/10.1017/s1049023x00040073.
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AbstractExposure to radiation induces a reduction in the number of gastrointestinal, anaerobic bacterial flora, and an increase in the number of Enterobacteriaceae that are associated with sepsis and mortality. Antimicrobials that suppress anaerobic flora have a deleterious effect on survival by promoting earlier enterobacterial sepsis. In contrast, in studies of animals and immunosuppressed patients, antimicrobials that inhibit gram-negative enteric bacteria and preserve the anaerobic flora have shown a beneficial effect by preventing bacterial translocation and fatal sepsis. The quinolone antimicrobials hold potential for therapy of endogenous and exogenous infection after irrodiation.
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Cheptsov, Vladimir S., Andrey A. Belov, Elena A. Vorobyova, Anatoli K. Pavlov e Vladimir N. Lomasov. "Effects of Radiation Intensity, Mineral Matrix, and Pre-Irradiation on the Bacterial Resistance to Gamma Irradiation under Low Temperature Conditions". Microorganisms 9, n.º 1 (19 de janeiro de 2021): 198. http://dx.doi.org/10.3390/microorganisms9010198.
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Ionizing radiation is one of the main factors limiting the survival of microorganisms in extraterrestrial conditions. The survivability of microorganisms under irradiation depends significantly on the conditions, in which the irradiation occurs. In particular, temperature, pressure, oxygen and water concentrations are of great influence. However, the influence of factors such as the radiation intensity (in low-temperature conditions) and the type of mineral matrix, in which microorganisms are located, has been practically unstudied. It has been shown that the radioresistance of bacteria can increase after their exposure to sublethal doses and subsequent repair of damage under favorable conditions, however, such studies are also few and the influence of other factors of extraterrestrial space (temperature, pressure) was not studied in them. The viability of bacteria Arthrobacter polychromogenes, Kocuria rosea and Xanthomonas sp. after irradiation with gamma radiation at a dose of 1 kGy under conditions of low pressure (1 Torr) and low temperature (−50 °C) at different radiation intensities (4 vs. 0.8 kGy/h) with immobilization of bacteria on various mineral matrices (montmorillonite vs. analogue of lunar dust) has been studied. Native, previously non-irradiated strains, and strains that were previously irradiated with gamma radiation and subjected to 10 passages of cultivation on solid media were irradiated. The number of survived cells was determined by culturing on a solid medium. It has been shown that the radioresistance of bacteria depends significantly on the type of mineral matrix, on which they are immobilized, wherein montmorillonite contributes to an increased survivability in comparison with a silicate matrix. Survivability of the studied bacteria was found to increase with decreasing radiation intensity, despite the impossibility of active reparation processes under experimental conditions. Considering the low intensity of radiation on various space objects in comparison with radiobiological experiments, this suggests a longer preservation of the viable microorganisms outside the Earth than is commonly believed. An increase in bacterial radioresistance was revealed even after one cycle of irradiation of the strains and their subsequent cultivation under favourable conditions. This indicates the possibility of hypothetical microorganisms on Mars increasing their radioresistance.
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Alcarde, André Ricardo, Júlio Marcos Melges Walder e Jorge Horii. "Fermentation of irradiated sugarcane must". Scientia Agricola 60, n.º 4 (dezembro de 2003): 677–81. http://dx.doi.org/10.1590/s0103-90162003000400011.
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Bacillus and Lactobacillus are bacteria that usually contaminate the ethanolic fermentation by yeasts and may influence yeast viability. As microorganisms can be killed by ionizing radiation, the efficacy of gamma radiation in reducing the population of certain contaminating bacteria from sugarcane must was examined and, as a consequence, the beneficial effect of lethal doses of radiation on some parameters of yeast-based ethanolic fermentation was verified. Must from sugarcane juice was inoculated with bacteria of the genera Bacillus and Lactobacillus. The contaminated must was irradiated with 2.0, 4.0, 6.0, 8.0 and 10.0 kGy of gamma radiation. After ethanolic fermentation by the yeast (Saccharomyces cerevisiae) the total and volatile acidity produced during the process were evaluated; yeast viability and ethanol yield were also recorded. Treatments of gamma radiation reduced the population of the contaminating bacteria in the sugarcane must. The acidity produced during the fermentation decreased as the dose rate of radiation increased. Conversely, the yeast viability increased as the dose rate of radiation increased. Gamma irradiation was an efficient treatment to decontaminate the must and improved its parameters related to ethanolic fermentation, including ethanol yield, which increased 1.9%.
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Sasaki, Takayuki, Tiit Kauri e Akira Kudo. "Effect of pH and temperature on the sorption of Np and Pa to mixed anaerobic bacteria". Applied Radiation and Isotopes 55, n.º 4 (outubro de 2001): 427–31. http://dx.doi.org/10.1016/s0969-8043(01)00104-x.
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Laheij, Alexa M. G. A., Johannes J. de Soet, Enno C. I. Veerman, Jan G. M. Bolscher e Cor van Loveren. "The Influence of Oral Bacteria on Epithelial Cell MigrationIn Vitro". Mediators of Inflammation 2013 (2013): 1–6. http://dx.doi.org/10.1155/2013/154532.
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Oral ulcerations often arise as a side effect from chemo- and radiation therapy. In a previous clinical study,Porphyromonas gingivaliswas identified as a positive predictor for oral ulcerations after hematopoetic stem cell transplantation, possibly incriminatingP. gingivalisin delayed healing of the ulcerations. Therefore, it was tested whetherP. gingivalisand its secreted products could inhibit the migration of oral epithelial cells in anin vitroscratch assay. To compare, the oral bacteriaPrevotella nigrescens,Prevotella intermedia,Tannerella forsythia, andStreptococcus mitiswere included. A standardized scratch was made in a confluent layer of human oral epithelial cells. The epithelial cells were challenged with bacterial cells and with medium containing secretions of these bacteria. Closure of the scratch was measured after 17 h using a phase contrast microscope.P. gingivalis,P. nigrescens, and secretions ofP. gingivalisstrongly inhibited cell migration. A challenge with 1000 heat-killed bacteria versus 1 epithelial cell resulted in a relative closure of the scratch of 25% forP. gingivalisand 20% forP. nigrescens. Weaker inhibitory effects were found for the other bacteria. The results confirmed our hypothesis that the oral bacteria may be involved in delayed wound healing.
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Sulatri, Ni Luh, Ida Bagus Agung Yogeswara e Ni Wayan Nursini. "Efektifitas sinar ultraviolet terhadap cemaran bakteri patogen pada makanan cair sonde untuk pasien immune-compremissed". Jurnal Gizi Indonesia (The Indonesian Journal of Nutrition) 5, n.º 2 (30 de junho de 2017): 112–18. http://dx.doi.org/10.14710/jgi.5.2.112-118.
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Background : Food safety remained as critical concern to immune-compremissed patient. Food safety assurance can be achieved through inhibition of pathogenic bacteria by physical treatment such as UV light radiation. However, a study regarding the effect of UV light on growth of pathogenic bacteria in contaminated liquid food are scarce.Objective : To determine the effectiveness of UV light on contamination of pathogenic bacteria in liquid food for immune-compremissed patient.Methods : Randomized design with two factor which were holding time for 60 and 120 minutes and radiation exposure (0, 5, 10 and 15 minutes). The data was analyzed using ANOVA Result : The viscosity and pH of liquid foods were 20 centipoise and 7,15 respectively. Radiation of UV light on contaminated food that have been incubated for 60 and 120 minutes at 37oC showed significant increase (1-2 log cycle) on growth of pathogenic bacteria.Conclusion : Radiation of UV light on contaminated liquid food were not effective to inhibit or kill pathogenic bacteria during holding time (60 and 120 minutes).
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STERMER, RAYMOND A., MARGARET LASATER-SMITH e CLAYTON F. BRASINGTON. "Ultraviolet Radiation—An Effective Bactericide for Fresh Meat". Journal of Food Protection 50, n.º 2 (1 de fevereiro de 1987): 108–11. http://dx.doi.org/10.4315/0362-028x-50.2.108.
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Ultraviolet radiation (UV), with principal energy at a wavelength of 253.7 nm, was effective in destroying bacteria on the surface of fresh meat. A radiation dose of 150 mW s/cm2 (275 uW/cm2 for 550 s) reduced bacteria on smooth surface meat (beef plate) about 2 log cycles (99% “kill”). Further increases in dose level to 500 mW s/cm2 (275 uW/cm2 for 1800 s) reduced the bacteria level one additional log cycle. Since UV radiation does not penetrate most opaque materials, it was less effective on rough surface cuts of meat such as round steak because bacteria were partly shielded from the radiation. Unlike gamma (ionizing) radiation, UV had no deleterious effects on color (Hunter “a”, redness) or general appearance. UV treatment chambers could be easily installed in new or existing meat processing facilities at relatively low cost. Experimental results indicate that UV irradiation of meat carcasses could effectively increase the lag phase of bacteria multiplication until adequate cooling had occurred.
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Xu, Fei, e Jaroslav Vostal. "Vitamin K3 Is a Potential Ultraviolet Photosensitizer for Pathogen Reduction of Human Platelets and Plasma". Blood 120, n.º 21 (16 de novembro de 2012): 3434. http://dx.doi.org/10.1182/blood.v120.21.3434.3434.
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Abstract Abstract 3434 Human platelets are stored up to 5 days at room temperature and may support bacterial growth before transfusion. Transfusion of bacterially contaminated platelets remains the highest transfusion transmitted infectious disease risk today. One approach to reducing this risk is the development of safe and effective pathogen reduction methodologies. We evaluated UV light (A and B) with vitamin K3 (VK3) as a photosensitizer for efficacy in reducing bacterial growth in platelet concentrates and plasma. Six species of bacteria, including Bacillus cereus, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, Klebsiella pneumoniae and Escherichia coli, were spiked respectively into phosphate buffered saline (PBS) buffer and exposed to UVA irradiation before bacterial growth was determined. As shown in Figure 1, the bacterial colony forming units (CFU) were reduced with increasing VK3 concentrations and UVA dosages. The VK3 at 400 uM plus UVA-radiation (2.88 J/cm2) significantly reduced the bacterial CFU in PBS spiked with bacteria. The same six-bacteria panel were spiked respectively into platelet concentrates (PCs) diluted with platelet additive solution and mixed with 400 uM VK3 before the UVA irradiation. As shown in Fig 2a, the bacteria CFU were reduced with increasing dosage of UVA but efficacy declined with lower dilution of PCs. At VK3 concentration of 400 uM and PC diluted to 20% a UVA-dose of 5.76 J/cm2 significantly reduced bacterial CFUs in PCs spiked with E coli, K pneumoniae, P aeruginosa and S epidermidis respectively. Similar results were obtained with the same six-bacteria panel spiked into plasma as shown in Fig 2b. UVB and VK3 combination had a biphasic inhibitory effect as shown in Fig 3. The VK3 at 200 uM plus UVB-radiation (0.015 J/cm2) also significantly reduced the CFU from the same six-bacteria panel spiked into PBS. However higher concentrations of 1600 uM VK3 could partially reverse the bacterial growth inhibition under UVB-radiation at 0.0038, 0.0075, and 0.015 J/cm2 for E coli, K pneumoniae and S aureus bacterial organisms. These findings suggest that VK3 may serve as an effective UVA photosensitizer for pathogen reduction of human platelets. With UVB light, lower concentrations of VK3 are effective at inhibiting bacterial proliferation but higher concentrations of VK3 may serve as a weak UVB blocker. Additional studies will need to be conducted to determine the impact of UV light and VK3 on platelet in vitro and in vivo performance. “This abstract reflects the views of the author and should not be construed to represent FDA's views or policies.” Disclosures: No relevant conflicts of interest to declare.
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Santos, Ana L., Vanessa Oliveira, Inês Baptista, Isabel Henriques, Newton C. M. Gomes, Adelaide Almeida, António Correia e Angela Cunha. "Effects of UV-B Radiation on the Structural and Physiological Diversity of Bacterioneuston and Bacterioplankton". Applied and Environmental Microbiology 78, n.º 6 (13 de janeiro de 2012): 2066–69. http://dx.doi.org/10.1128/aem.06344-11.
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ABSTRACTThe effects of UV radiation (UVR) on estuarine bacterioneuston and bacterioplankton were assessed in microcosm experiments. Bacterial abundance and DNA synthesis were more affected in bacterioplankton. Protein synthesis was more inhibited in bacterioneuston. Community analysis indicated that UVR has the potential to select resistant bacteria (e.g.,Gammaproteobacteria), particularly abundant in bacterioneuston.
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Carrillo, P., J. M. Medina-Sánchez, C. Durán, G. Herrera, V. E. Villafañe e E. W. Helbling. "Synergistic effects of UVR and simulated stratification on commensalistic phytoplankton–bacteria relationship in two optically contrasting oligotrophic Mediterranean lakes". Biogeosciences 12, n.º 3 (4 de fevereiro de 2015): 697–712. http://dx.doi.org/10.5194/bg-12-697-2015.
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Abstract. An indirect effect of global warming is a reduction in the depth of the upper mixed layer (UML) causing organisms to be exposed to higher levels of ultraviolet (UVR, 280–400 nm) and photosynthetically active radiation (PAR, 400–700 nm). This can affect primary and bacterial production as well as the commensalistic phytoplankton–bacteria relationship. The combined effects of UVR and reduction in the depth of the UML were assessed on variables related to the metabolism of phytoplankton and bacteria, during in situ experiments performed with natural pico- and nanoplankton communities from two oligotrophic lakes with contrasting UVR transparency (high-UVR versus low-UVR waters) of southern Spain. The negative UVR effects on epilimnetic primary production (PP) and on heterotrophic bacterial production (HBP), intensified under increased stratification, were higher in the low-UVR than in the high-UVR lake, and stronger on the phytoplanktonic than on the heterotrophic bacterial communities. Under UVR and increased stratification, the commensalistic phytoplankton–bacteria relationship was strengthened in the high-UVR lake where excretion of organic carbon (EOC) rates exceeded the bacterial carbon demand (BCD; i.e., BCD : EOC(%) ratio < 100). This did not occur in the low-UVR lake (i.e., BCD : EOC(%) ratio > 100). The greater UVR damage to phytoplankton and bacteria and the weakening of their commensalistic interaction found in the low-UVR lake indicates that these ecosystems would be especially vulnerable to UVR and increased stratification as stressors related to global climate change. Thus, our findings may have important implications for the carbon cycle in oligotrophic lakes of the Mediterranean region.
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Pantyo, V. V., V. I. Pantyo e E. M. Danko. "The impact of piler-radiation on the growth rate of opportunistic microorganisms". Reports of Vinnytsia National Medical University 22, n.º 2 (5 de dezembro de 2018): 272–75. http://dx.doi.org/10.31393/reports-vnmedical-2018-22(2)-07.
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The spread of resistant to antimicrobial agents strains of opportunistic microorganisms causes the search for new ways of struggle with them. Among these ways, special attention is drawn to the use of physical factors, in particular, different types of radiation, with potential antimicrobial activity. Purpose: to investigate the direct effect of the PILER wave length line on the growth rate of S.aureus ATCC 25923 and P.aeruginosa ATCC 27853 on solid nutrient media. The influence of PILER (Polarized Polychromatic Incoherent Low Energy Radiation) on various wavelengths on the growth intensity of the collection test- strains of S.aureus ATCC 25923 and P.aeruginosa ATCC 27853 on solid nonselective nutrient media (NA) was investigated. The results were determined by counting the number of bacterial colonies on the dishes and compared with control – similar unirradiated cultures. The effect of PILER of different wavelengths and exposures (5, 10, 15 and 20 min) was investigated by separate series. PILER light source – Med All Bioptron light therapy system by Zepter Group. The obtained results testify to the significant influence of PILER radiation on the intensity of the growth of research objects. The degree of influence depended on the duration of irradiation and showed insignificant stimulation of the growth of bacteria in 5–10-minute exposures and expressed bactericidal and bacteriostatic effect at exposure for 20 minutes. The 20-minute exposure PILER on the S.aureus 25923 strain resulted in a decrease of the number of bacterial colonies by 37–65% compared to control, P.aeruginosa 27853 – by 58–81% compared to control. PILER has a significant modulator effect on the growth of the examined conditionally pathogenic microorganisms on solid nutrient media. The degree of this effect depends on the radiation parameters, in particular on the dose density and the wavelength of light, and at exposures of 20 minutes is manifested in marked bactericidal and bacteriostatic effects on microorganisms.
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Ulianova, O. V., S. S. Ulyanov, Zhang Zhihong, Zhou Sibo e Qingming Luo. "Biophysical aspects of effects of laser radiation on living systems: II. Effect on Pseudomonas aeruginosa bacteria". Optics and Spectroscopy 107, n.º 6 (dezembro de 2009): 927–33. http://dx.doi.org/10.1134/s0030400x09120157.
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Burchard, Thomas, Lamprini Karygianni, Elmar Hellwig, Marie Follo, Thomas Wrbas, Annette Wittmer, Kirstin Vach e Ali Al-Ahmad. "Inactivation of oral biofilms using visible light and water-filtered infrared A radiation and indocyanine green". Future Medicinal Chemistry 11, n.º 14 (julho de 2019): 1721–39. http://dx.doi.org/10.4155/fmc-2018-0522.
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Aim: To investigate the antimicrobial photodynamic therapy (aPDT) of visible light and water-filtered infrared A radiation in combination with indocyanine green (ICG) on planktonic oral microorganisms as well as on oral biofilm. Methods: The irradiation was conducted for 5 min in combination with ICG. Treatment with chlorhexidine served as a positive control. The number of colony forming units and bacterial vitality were quantified. Results: All tested bacterial strains and salivary bacteria were killed at a level of 3log10. The colony forming units of the initial mature oral biofilms were strongly reduced. The high bactericidal effect of aPDT was confirmed by live/dead staining. Conclusion: The aPDT using visible light and water-filtered infrared A radiation and ICG has the potential to treat periodontitis and peri-implantitis.
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They, Ng Haig, David Motta Marques, Rafael Siqueira Souza e Lúcia Ribeiro Rodrigues. "Short-Term Photochemical and Biological Unreactivity of Macrophyte-Derived Dissolved Organic Matter in a Subtropical Shallow Lake". Journal of Ecosystems 2013 (30 de julho de 2013): 1–9. http://dx.doi.org/10.1155/2013/316709.
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Macrophytes have been associated with low bacterial metabolism in the littoral zones of lake Mangueira, but an explanation for this pattern is largely unknown. In this study, macrophyte-derived DOM was incubated in situ for the measurement of the effect of grazers, bacteria, and light on its degradation in three experiments. The water was separated in bulk, bacterial, and control (+ HgCl2) fractions and exposed to or hidden from sunlight for 120 h. Unchange in bacterial variables in the bulk fraction suggested a combined control of radiation and grazing on bacteria. Light treatment increased bacterial density but not biomass and biovolume, while bacterial density decreased in the dark. Significant fading of water color in the bacterial fraction only occurred after light exposure, indicating a complementary pathway of light and bacteria. DOC and the Abs250 : 365 ratio did not change with incubation, indicating no net change of DOC pool and reactivity. Due to continuous carbon loading from macrophytes and low UV irradiance, the very low rates of DOM degradation provide the mechanistic explanation for the observed impacts of macrophytes in lake’s carbon metabolism in littoral zones.
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Shah, Surabhi K., Edward A. Mcbean e William A. Anderson. "Preliminary studies into the disinfection of potable water using solar radiation". Canadian Journal of Civil Engineering 23, n.º 2 (1 de abril de 1996): 373–80. http://dx.doi.org/10.1139/l96-042.
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The efficacy and kinetics of water disinfection using solar radiation was studied, with respect to potential household or individual use in regions where treated drinking water is unavailable. Small volumes of sterilized water (1 L or less) were deliberately contaminated with various concentrations of Escherichia coli, and then exposed to solar radiation for several hours with periodic bacterial enumeration using plate count methods. An agar which was selective for fecal coliforms (mFC) was found to be inappropriate in this work as it often gave false negative counts, compared to the nonselective total plate count agar. The die-off of bacteria could be modelled, as a function of cumulative solar dose, in an exponential decay model. Decay rate constants of 0.071 to 0.486 m2∙MJ−1 were estimated. Volumes of 250 mL or less (in a 1 L bottle), and waters with lower bacterial concentrations or higher ionic strength, exhibited higher rates of die-off. Bacterial counts could be reduced from several thousands to less than 1 per millilitre (lower detection limit) during one day of solar irradiation. The source of the water and bottle material had a significant effect on the die-off rate. A Weibull distribution-based model has a conceptually better theoretical basis, and also fits the experimental data adequately at low and high doses. At intermediate solar doses, the Weibull model fit tended to underestimate the bacterial inactivation whereas the exponential decay model overestimated it. While solar disinfection appears useful for bacterial inactivation, it may be ineffective in situations where the major contaminants are the more UV resistant viruses or parasites, or where significant competition from physical or chemical water characteristics exists. It is not likely to be a suitable alternative to conventional chemical disinfection, but may be applicable in situations where no other disinfection is available. Key words: solar disinfection, potable water, coliform bacteria, inactivation kinetics, modelling.
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EL-NEZAMI, HANI, PASI KANKAANPÄÄ, SEPPO SALMINEN e JORMA AHOKAS. "Physicochemical Alterations Enhance the Ability of Dairy Strains of Lactic Acid Bacteria To Remove Aflatoxin from Contaminated Media†". Journal of Food Protection 61, n.º 4 (1 de abril de 1998): 466–68. http://dx.doi.org/10.4315/0362-028x-61.4.466.
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Lactobacillus rhamnosus GG and Lactobacillus rhamnosus LC-705, previously shown to effectively bind to aflatoxin B1, were subjected to various Chemical and physical treatments to examine the effects of these treatments on the binding affinity of these strains towards aflatoxin B1. Treatment of bacterial pellets of both strains with hydrochloric acid significantly (P < 0.05) enhanced the binding ability when compared to nontreated pellets or pellets treated by other methods. An enhancement of bacterial ability to bind aflatoxin B1 was also observed when the bacterial pellets were subjected to heat treatment by either autoclaving or boiling at 100°C in a water bath, but the impact of these two treatments was not as effective as the acid treatment. Ethanol, UV radiation, sonication, alkaline, or pH treatments either had no effect or reduced the binding ability of the bacteria.
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Choi, Jeongyun, Aritra Roy Choudhury, Song-yi Park, Myung Min Oh e Tongmin Sa. "Inoculation of ACC Deaminase-Producing Brevibacterium linens RS16 Enhances Tolerance against Combined UV-B Radiation and Heat Stresses in Rice (Oryza sativa L.)". Sustainability 13, n.º 18 (7 de setembro de 2021): 10013. http://dx.doi.org/10.3390/su131810013.
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UV-B radiation and high temperature have detrimental effects on plant physiological and biochemical processes. The use of bacterial inoculants for stress alleviation has been regarded as a sustainable and eco-friendly approach. Hence, this study was conducted to evaluate the ability of 1-aminocyclopropane-1-caboxylate (ACC) deaminase-producing Brevibacterium linens RS16 in enhancing stress tolerance in rice against combined UV-B radiation and heat stresses. A combination of 0.5 Wm−2 UV-B radiation and 40 °C of temperature were imposed on rice plants for 5 days. The plants imposed with combined stress had shown significantly higher ethylene emissions compared to the plants grown under normal conditions. In addition, the stress imposition had shown negative effects on the photosynthetic traits, biomass, and genetic material of rice plants. The inoculation of bacteria had shown a 26.5% and 31.8% decrease in ethylene emissions at 3 and 4 days of stress imposition compared to the non-inoculated plants. Additionally, bacterial inoculation had also enhanced plant biomass and photosynthetic traits, and had proved to be effective in restricting DNA damage under stress conditions. Taken together, the current study has shown the effective strategy of enhancing stress tolerance against the interactive effects of UV-B radiation and heat stresses by regulation of ethylene emissions through inoculating ACC deaminase-producing bacteria.
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Al-doori1, Aidah Abd, Awatef Saber Jasem1 e Adnan F. AL-Azzawie2. "Effects of Nd:Yag Laser on some virulence factor genes of Pseudomonas aeruginosa bacteria". Tikrit Journal of Pure Science 25, n.º 2 (17 de março de 2020): 86. http://dx.doi.org/10.25130/j.v25i2.962.
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The aim of this study was to assess effects of the 532nm Nd-yag laser on the genes of Tox A, Exo S, and Opr L, of Pseudomonas aeruginosa (P. aeruginosa) bacteria isolated from clinical (wounds, burns, otitis media) and environmental (water, soil) samples. Clinical samples were collected from patients coming to Saladdin General Hospital from wound, burns and middle ear infections while environmental samples were extracted from water and soil for Saladdin General Hospital . Bacterial samples irradiated by Nd-Yag laser with wavelength of 532 nm using energies (300mj,500mj) with (15 and 25 sec) and genomic DNA were extracted from all samples after the diagnosis of P. aeruginosa bacteria depending on the macroscopic and biochemical examination, then the PCR technique was performed. The results have shown an impact on P. aeruginosa bacteria of Nd-Yag laser by comparing PCR results of treated samples with control (unexposed) as loss of normal bands. This indicates that the laser had a genetic effect on the P. aeruginosa bacteria. We conclude that the laser induces genetic changes in P. aeruginosa's DNA so that lasers can be used in treatment and sterilization for clinical and environmental . The PCR technique could be used as a biomarker study to determine the biological effects of radiation on bacteria.
http://dx.doi.org/10.25130/tjps.25.2020.034
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Janisiewicz, W. J., T. van der Zwet e P. B. Jahrling. "Laboratory studies on the effect of gamma radiation on Erwinia amylovora survival on apple fruit". Canadian Journal of Microbiology 32, n.º 10 (1 de outubro de 1986): 787–90. http://dx.doi.org/10.1139/m86-144.
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Susceptibility of Erwinia amylovora to gamma irradiation was determined in vitro on test tube cultures and in vivo on apples and pears. Bacterial strains differed in susceptibility to irradiation. Higher doses of irradiation (ca. 80 krad (1 krad = 10 Gy)) were needed to kill the bacterium on fruit compared with test tube cultures (from 20 to more than 50 krad). Fruit with natural populations of E. amylovora collected from a severely blighted orchard, exposed to doses of 140 krad, still contained viable bacteria. Surviving E. amylovora were pathogenic to green 'Bartlett' pears. Five radiation-sensitizing chemicals (used previously against different pathogens on other commodities) were tested against E. amylovora. N-Ethylmaleimide sensitized the bacteium to gamma irradiation. Treatment of natural populations of the bacterium on apples with N-ethylmaleimide eliminated E. amylovora from the apple surface with a gamma irradiation dose one-third lower than the maximum rate tolerable by fruit.
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Kunarti, Sri, Amellia Tjandra e Edhie Arif Prasetyo. "EFFICACY OF DIODE LASSER 405 NM WITH CHLOROPHYLLS AS PHOTOSENSITIZER ON Enterococcus faecalis". Conservative Dentistry Journal 8, n.º 2 (5 de dezembro de 2019): 91. http://dx.doi.org/10.20473/cdj.v8i2.2018.91-95.
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Background: The presence of persistent infections in the root canals by microorganisms causes root canal failure. The most commonly found bacteria that cause persistent infection is Enterococcus faecalis. PDI / photodynamic inactivation is an in vitro approach to inactivation of microorganisms. The combination of light and photosensitivity of chlorophyll in PDI will cause photoinactivation in bacteria. Long radiation of PDT can affect the production of singlet oxygen and ROS (Reactive Oxygen Species) to kill Enterococcus faecalis bacteria. Objective: To prove the effect of 405 nm laser diode with and without chlorophyll photosensitizer and the irradiation effect of 405 nm laser diode on the number of CFU of Enterococcus faecalis bacteria. Method: This study used the Enterococcus faecalis bacteria cultur which was divided into 5 groups. Group I as control group, Group II irradiation 30 ', III chlorophyll + irradiation 30', IV irradiation 60 ', V chlorophyll + irradiation 60'. After incubation, the bacteria count was calculated with Quebec Colony Counter and analyzed by Shapiro-Wilk test, Levene test and Anova test. Results: There were significant differences (p <0.05) between the number of colonies of Enterococcus faecalis bacteria in each treatment group. Longer duration of PDT exposure (Group II and IV) with chlorophyll showed less number of Enterococcus faecalis bacteria. Conclusion: The longer the PDT irradiation, the less number of Enterococcus faecalis bacteria. The 60-second radiation with chlorophyll showed the least amount of Enterococcus faecalis bacteria.
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Zieliński, Marcin, e Magdalena Zielińska. "Impact of microwave radiation on nitrogen removal and quantity of nitrifiers in biofilmA paper submitted to the Journal of Environmental Engineering and Science." Canadian Journal of Civil Engineering 37, n.º 4 (abril de 2010): 661–66. http://dx.doi.org/10.1139/l09-171.
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The aim of this study was to determine the impact of microwave radiation on the efficiency of nitrification and on the percentage of ammonia-oxidizing bacteria in biofilm and to study the possibility of the occurrence of nonthermal effects caused by the interaction of microwaves and biofilm. Eight trickling filters with a biofilm were used in the experiment: four were exposed to microwave radiation, and four were heated with warm air as a control group. Microwave radiation at a frequency of 2.45 GHz was applied at an intensity of 18 W (0.01 W·cm–3of the reactor packing), which increased the biofilm temperature by 6 °C compared with the ambient temperature. The hydraulic loading averaged 0.30 m3·m–2·h–1, and the organic loading equalled 1.93 g chemical oxygen demand (COD)·m–2·d–1. Microwave radiation had an effect on the concentration of nitrogen compounds in the biofilm, and microwave heating triggered alterations within the biofilm that increased the efficiency of both nitrification and denitrification and the percentage of ammonia-oxidizing bacteria.
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Malalur, Pannaga G., Xiaokui Mo, Rebecca Hoyd, David Paul Carbone e Daniel Spakowicz. "Intra-tumoral microbes and overall survival in colorectal cancer patients." Journal of Clinical Oncology 38, n.º 15_suppl (20 de maio de 2020): 4083. http://dx.doi.org/10.1200/jco.2020.38.15_suppl.4083.
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4083 Background: The presence of certain bacteria among or adjacent to tumor cells may contribute to colorectal cancer (CRC) development. However, the effect of the tumor microbiome on survival in CRC patients undergoing treatment is poorly understood. We hypothesize that intra-tumoral microbes correlate with overall survival (OS) in CRC patients. Methods: We obtained RNA-seq data from CRC tumor biopsies from patients treated at The Ohio State University Comprehensive Cancer Center as part of the Oncology Research Information Exchange Network (ORIEN). Reads were aligned to human and exogenous genomes using TopHat2 and Kraken2/Bracken, respectively. Results: The analyzed cohort included 99 CRC patients with an age range from 31-83 years, 62% female, and 44% with metastatic CRC. Therapies received prior to sample collection were grouped into chemotherapy with or without radiation (37%), antiVEGF/EGFR therapies (33%), no systemic therapy (23%), immunotherapy (3%); 3% were unknown. Overall, eleven bacteria were significantly associated with shorter OS, including a species in the genus Clostridium and Vibrio. Conversely, five other bacteria including several commensal gut microbes, were associated with longer OS. In patients who received chemotherapy with or without radiation (n = 38), several microbes were significantly associated with shorter OS, including a member of the genus Streptomyces. Only three bacteria were significantly associated with longer OS. In the patients who received antiVEGF/EGFR therapies (bevacizumab, cetuximab, panitumumab) (n = 33), several bacterial taxa were associated with shorter OS. In addition, bacteria including a member of the genera Bacillus and Staphylococcus were significantly associated with metastatic CRCs. (p < 0.05 for all, Fisher’s Exact tests). Conclusions: This study suggests that demonstrating the presence or absence of certain microbes in tumor biopsies could have important therapeutic implications for CRC patients. Only bacteria (no fungi, viruses, archaea, etc.) were found to significantly associate with OS across the entire cohort and within treatment subsets. The presence of bacteria was mostly, but not always, associated with worse OS. Antibiotics targeted towards bacterial species associated with negative outcomes could have the potential to improve OS in CRC patients.
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Bekturova, Assemgul, Zhannur Markhametova e Zhaksylyk Masalimov. "Plasmids Role in Survival of Acinetobacter calcoaceticus A1 Exposed to UV-Radiation and Hydrocarbons". Advanced Materials Research 905 (abril de 2014): 151–55. http://dx.doi.org/10.4028/www.scientific.net/amr.905.151.
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The role of plasmids in hydrocarbon-degrading bacteriaAcinetobacter calcoaceticus A1survival to UV-radiation and hydrocarbons was studied. Natural plasmids-containingA. calcoaceticus A1showed high resistance to UV-radiation.A. calcoaceticus A1showed active growth under exposed to UV-radiation for up to 30 minutes. Combined effects of UV-radiation and petroleum hydrocarbons did not considerably reduce the growth of strains. It was shown a stimulating effect of UV-radiation on the growth curves of strains ofA. calcoaceticus A1. Constructed recombinant strain (E.coli XL blueRec) showed the ability to grow on medium with addition petroleum hydrocarbons. Combined effects of UV-radiation and petroleum hydrocarbons have had a negative effect on the growth ofE.coli XL blueRec. Thus, results showed that the plasmid DNA of natural hydrocarbon-degrading bacteriaA. calcoaceticus A1may contain genes of microbial resistance to UV - radiation and petroleum hydrocarbons.