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Mesophile

From Wikipedia, the free encyclopedia

Amesophileis anorganismthat grows best in moderatetemperature,neither too hot nor too cold, with an optimum growth range from 20 to 45 °C (68 to 113 °F).[1]The optimum growth temperature for these organisms is 37 °C (about 99 °F).[2]The term is mainly applied tomicroorganisms.Organisms that prefer extreme environments are known asextremophiles.Mesophiles have diverse classifications, belonging to twodomains:Bacteria,Archaea,and tokingdomFungiof domainEucarya.Mesophiles belonging to the domain Bacteria can either begram-positiveorgram-negative.Oxygen requirements for mesophiles can beaerobicoranaerobic.There are three basic shapes of mesophiles:coccus,bacillus,andspiral.

Habitat

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The habitats of mesophiles can includecheeseandyogurt.They are often included during fermentation ofbeerandwinemaking. Since normal human body temperature is 37°C,the majority of humanpathogensare mesophiles, as are most of the organisms comprising thehuman microbiome.

Mesophiles vs. extremophiles

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Mesophiles are the opposite ofextremophiles.Extremophiles that prefer cold environments are termedpsychrophilic,those preferring warmer temperatures are termedthermophilic or thermotropicand those thriving in extremely hot environments arehyperthermophilic. A genome-wide computational approach has been designed by Zheng, et al. to classify bacteria into mesophilic and thermophilic.[3]

Adaptations

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All bacteria have their own optimum environmental surroundings and temperatures in which they thrive. Many factors are responsible for a given organism's optimal temperature range, but evidence suggests that the expression of particular genetic elements ([alleles]) can alter the temperature-sensitive phenotype of the organism. A study published in 2016 demonstrated that mesophilic bacteria could be genetically engineered to express certain alleles from psychrophilic bacteria, consequently shifting the restrictive temperature range of the mesophilic bacteria to closely match that of the psychrophilic bacteria.[4]

Due to the less stable structure of mesophiles, it has reduced flexibility forprotein synthesis.[5]Mesophiles are not able to synthesize proteins in low temperatures. It is more sensitive to temperature changes, and thefatty acidcomposition of themembranedoes not allow for muchfluidity.[6]Decreasing the optimal temperature of 37 °C to 0 °C to 8 °C leads to a gradual decrease in protein synthesis.Cold-induced proteins(CIPs) are induced during low temperatures, which then allowscold-shock proteins(CSPs) to synthesize. The shift back to the optimal temperature sees an increase, indicating that mesophiles are highly dependent on temperature.[7]Oxygen availability also affects microorganism growth.[8]

There are two explanations for thermophiles being able to survive at such high temperatures whereas mesophiles can not. The most evident explanation is that thermophiles are believed to have cell components that are relatively more stable than the cell components of mesophiles which is why thermophiles are able to live at higher temperatures than mesophiles.[9]"A second school of thought, as represented by the writings of Gaughran (21) and Allen (3), believes that rapid resynthesis of damaged or destroyed cell constituents is the key to the problem of biological stability to heat."[9]

Oxygen requirements

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Due to the diversity of mesophiles, oxygen requirements greatly vary.Aerobic respirationrequires the use ofoxygenand anaerobic does not. There are three types ofanaerobes.Facultative anaerobesgrow in the absence of oxygen, usingfermentationinstead. During fermentation, sugars are converted toacids,alcohol,orgases.If there is oxygen present, it will use aerobic respiration instead.Obligate anaerobescannot grow in the presence of oxygen.Aerotolerant anaerobescan withstand oxygen.

Roles

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Microorganisms play an important role indecompositionof organic matter andmineralizationofnutrients.Inaquaticenvironments, the diversity of theecosystemallows for the diversity of mesophiles. The functions of each mesophile rely on the surroundings, most importantly temperature range.[10]Bacteriasuch as mesophiles andthermophilesare used in thecheesemakingdue to their role infermentation."Traditionalmicrobiologistsuse the following terms to indicate the general (slightly arbitrary) optimum temperature for the growth of bacteria:psychrophiles(15–20 °C), mesophiles (30–37 °C), thermophiles (50–60 °C) and extreme thermophiles (up to 122 °C) ".[11]Both mesophiles and thermophiles are used in cheesemaking for the same reason; however, they grow, thrive and die at different temperatures.Psychrotrophic bacteriacontribute to dairy products spoiling, getting mouldy or going bad due to their ability to grow at lower temperatures such as in a refrigerator.

Examples

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Some notable mesophiles includeListeria monocytogenes,Staphylococcus aureus,andEscherichia coli.Other examples ofspeciesof mesophiles areClostridium kluyveri,Pseudomonas maltophilia,Thiobacillus novellus,Streptococcus pyogenes,andStreptococcus pneumoniae.Different types of diseases and infections typically have pathogens from mesophilic bacteria such as the ones listed above.

Listeria monocytogenes

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Listeria monocytogenesis a gram-positive bacterium. It is closely related toBacillusandStaphylococcus.It is a rod-shaped, facultative anaerobe that is motile by peritrichousflagella.L. monocytogenesmotility is limited from 20 °C to 25 °C.[12]At the optimal temperature, it loses its motility. This bacterium is responsible forlisteriosiswhich derives from contaminated food.[12]

Staphylococcus aureus

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Staphylococcus aureuswas first identified in 1880.[13]It is responsible for different infections stemming from an injury. The bacterium overcomes the body's natural mechanisms. Long lasting infections ofS. aureusincludespneumonia,meningitis,andosteomyelitis.S. aureusis commonly contracted in hospital settings.[13]

Escherichia coli

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Escherichia coliis a gram-negative, rod-shaped facultative anaerobic bacterium that does not producespores.[14]The bacterium is a member ofEnterobacteriaceae.It is capable of producingenterotoxinswhich arethermolabileorthermostable.[14]Other characteristics ofE. coliare that it isoxidase-negative,citrate-negative,methyl-redpositive, andVoges-Proskauer-negative. To sum upE. coli,it is acoliform.It is able to useglucoseandacetateas a carbon source for fermentation.E. coliis commonly found in thegutof living organisms.[15]E. colihas many capabilities such as being ahostforrecombinant DNAand being a pathogen.[15]

See also

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References

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  1. ^Willey, Joanne M., Linda Sherwood, Christopher J. Woolverton, and Lansing M. Prescott. Prescott, Harley, and Klein's Microbiology. New York: McGraw-Hill Higher Education, 2008. Print.
  2. ^Schiraldi, Chiara; De Rosa, Mario (2016),"Mesophilic Organisms",in Drioli, Enrico; Giorno, Lidietta (eds.),Encyclopedia of Membranes,Berlin, Heidelberg: Springer, pp. 1–2,doi:10.1007/978-3-642-40872-4_1610-2,ISBN978-3-642-40872-4,retrieved2022-05-22
  3. ^Hao Zheng; Hongwei Wu (2010)."Gene-centric association analysis for the correlation between the guanine-cytosine content levels and temperature range conditions of prokaryotic species".BMC Bioinformatics.11(Suppl 11): S7.doi:10.1186/1471-2105-11-S11-S7.PMC3024870.PMID21172057.
  4. ^Pankowski, Jarosław A.; Puckett, Stephanie M.; Nano, Francis E. (15 March 2016)."Temperature Sensitivity Conferred by ligA Alleles from Psychrophilic Bacteria upon Substitution in Mesophilic Bacteria and a Yeast Species".Applied and Environmental Microbiology.82(6): 1924–1932.Bibcode:2016ApEnM..82.1924P.doi:10.1128/AEM.03890-15.ISSN0099-2240.PMC4784036.PMID26773080.
  5. ^Vijayabaskar, Mahalingam S. et al. "Construction of Energy Based Protein Structure Networks: Application in the Comparative Analysis of Thermophiles and Mesophiles" Biophysical Journal, Volume 98, Issue 3, 387a
  6. ^Li, K.Y.; Torres, J. A. (1993)."EFFECTS of TEMPERATURE and SOLUTE ON the MINIMUM WATER ACTIVITY FOR GROWTH and TEMPERATURE CHARACTERISTIC of SELECTED MESOPHILES and PSYCHROTROPHS".Journal of Food Processing and Preservation.17(4): 305–318.doi:10.1111/j.1745-4549.1993.tb00733.x.
  7. ^Perrot, F., Hébraud, M., Junter, G.-A. and Jouenne, T. "Protein synthesis in Escherichia coli at 4°C. Electrophoresis." 2000, 21: 1625–1629. doi:10.1002/(SICI)1522-2683(20000501)21:8<1625::AID-ELPS1625>3.0.CO;2-4
  8. ^Sinclair, N. A.; Stokes, J. L. "ROLE OF OXYGEN IN THE HIGH CELL YIELDS OF PSYCHROPHILES AND MESOPHILES AT LOW TEMPERATURES." The Journal of Bacteriology, 1963, Vol. 85(1), p.164 [Peer Reviewed Journal]
  9. ^abKoffler, Henry (2016-11-28)."Protoplasmic differences between mesophiles and thermophiles".Bacteriological Reviews.21(4): 227–240.doi:10.1128/MMBR.21.4.227-240.1957.ISSN0005-3678.PMC180904.PMID13488883.
  10. ^Ferroni, G.D., Kaminski, J.S. "Psychrophiles, psychrotrophs, and mesophiles in an environment which experiences seasonal temperature fluctuations." Canadian Journal of Microbiology, 1980, 26:1184-1191, 10.1139/m80-198
  11. ^Johnson, Mark. "Mesophilic and Thermophilic Cultures Used in Traditional Cheesemaking." Cheese and Microbes. Washington: ASM Publishing. 2014. Web.
  12. ^abMagalhã£Es, R. (2014). Listeria monocytogenes. 450-461.
  13. ^abTodd, E. (2014). Staphylococcus Aureus. 530-534
  14. ^abRobinson, Richard K.. (2000). Encyclopedia of Food Microbiology, Volumes 1-3 - Escherichia Coli. Elsevier. Online version available at:http://app.knovel.com/hotlink/pdf/id:kt0051LGG3/encyclopedia-food-microbiology/escherichia-coli
  15. ^abRobinson, Richard K.. (2000). Encyclopedia of Food Microbiology, Volumes 1-3 - Escherichia Coli. Elsevier. Online version available at:http://app.knovel.com/hotlink/pdf/id:kt0051K7I1/encyclopedia-food-microbiology/ecology-bacteria-escherichia-3
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