Microbial ecology

Microbial ecology (or environmental microbiology) is a discipline where the interaction of microorganisms and their environment are studied.^[2] Microorganisms are known to have beneficial, neutral and harmful ecological relationships within their species and other species.^[2] Many scientists have studied the relationship between nature and microorganisms: Martinus Beijerinck, Sergei Winogradsky, Louis Pasteur, Robert Koch, Lorenz Hiltner, Dionicia Gamboa and many more,^[3][4][5][6] to understand the specific roles that these microorganisms have in biological and chemical pathways and the evolution of these microorganisms. Currently, there are several types of biotechnologies that have allowed scientists to analyze the biological and chemical properties of these microorganisms.^[7]

Many of these microorganisms have been known to form different symbiotic relationships with other organisms in their environment.^[8] Some symbiotic relationships include mutualism, commensalism, amensalism, and parasitism.^[9][10]

In addition, certain antimicrobial substances in the environment can kill microorganisms, thus preventing them from interacting with their environment. These can be antibiotic, antifungal, or antiviral.^[11]

Martinus Beijerinck invented the enrichment culture, a fundamental method culturing organisms for studying microbes from the environment. Sergei Winogradsky was one of the first researchers to attempt to understand microorganisms outside of the medical context—making him among the first students of microbial ecology and environmental microbiology—discovering chemosynthesis and developing the Winogradsky column in the process.^[12]:644

Louis Pasteur was a French chemist who derived key microbial principles that we use today: microbial fermentation, pasteurization, germ theory, and vaccines.^[13] These principles have served as a foundation for scientists in viewing the relationship between microbes and their environment.^[13] For example, Pasteur disproved the theory of spontaneous generation, the belief of life arising from nonliving materials.^[14] Pasteur stated that life can only come from life and not nonliving materials.^[15] This led to the idea that microorganisms were responsible for the microbial growth in any environment.^[15]

Robert Koch was a physician-scientist who implemented the use of an oil-immersion lens and a condenser while using microscopes, to increase the imagery of viewing bacteria.^[16] This led Koch to be the first publisher of bacteria photographs. As a result, Koch was able to study wound infections in animals at the microscopic level.^[16] He distinguished between distinct bacteria species, which led him to believe that the best way to study a certain disease is to focus on a specific pathogen.^[16] In 1879, Koch started to develop "pure" cultures to grow bacteria colonies.^[16] These advancements led Koch to solve the Cholera pandemic in India during the year 1883.^[16] Koch's laboratory techniques and materials led him to conclude that the use of unfiltered water that contained the bacteria thought to cause intestinal harm was causing the cholera pandemic.^[16]

Lorenz Hiltner is known as one of the pioneers in "microbial ecology."^[4] His research focused on how microbials in the rhizosphere provided nutrients to plants. Hiltner stated that the quality of plant products was a result of the plant's roots microflora.^[4] One of Hiltner contributions to the study of plant nutrition and soil bacteriology was creating antimicrobial seeds covered with mercury chloride.^[4] The sole purpose of creating the antimicrobial seeds were to protect the seeds from the harmful effects of pathogenic fungi. In addition, he recognized the known bacteria that were responsible for the nitrogen cycle: denitrification, nitrification, and nitrogen fixation.^[4]

Microorganisms are the backbone of all ecosystems, even in areas where photosynthesis cannot take place. For example, chemosynthetic microorganisms are the primary producers in extreme environments, such as high temperature geothermal environments.^[17] In these extreme conditions, the chemosynthetic microbes provide energy and carbon to other organisms. Chemosynthetic microorganisms gain energy by oxidizing inorganic compounds such as hydrogen, nitrite, ammonia, sulfur and iron (II). These organisms can be found in both aerobic and anaerobic environment.^[18]

The nitrogen cycle, phosphorus cycle, sulphur cycle, and carbon cycle depend on microorganisms also. Each cycle involves microorganisms in certain processes.^[19] For example, nitrogen gas makes up 78% of the Earth's atmosphere, but it is almost chemically inert; as a result, it is unavailable to most organisms. It has to be converted biologically to an available form by microorganism, through nitrogen fixation.^[20] Through these biogeochemical cycles, microorganisms are able to make nutrients such as nitrogen, phosphorus and potassium available in the soil.^[21] Microorganisms play a role in solubilizing phosphate, improving soil health, and plant growth.^[22]

微生物の相互作用はバイオレメディエーションに見られます。バイオレメディエーションは、微生物を使用して土壌^{[ 23 ]}や廃水^{[ 24 ]}から汚染物質を除去する技術です。 ^{[ 25 ] [ 26 ]}バイオレメディエーションで役割を果たす微生物の例としては、Pseudomonas、Bacillus、Arthrobacter、Corynebacterium、Methosinus、Rhodococcus、Stereum hirsutum、メタン生成菌、Aspergilus niger、Pleurotus ostreatus、Rhizopus arrhizus、Azotobacter、Alcaligenes、Phormidium v​​alderium、Ganoderma applantusなどがあります。^{[ 27 ]}

微生物群集間での水平遺伝子伝達のレベルが高いため、 ^{[ 28 ]}微生物生態学は進化の研究にも重要である。^{[ 29 ]}

抗菌剤は微生物を殺すことができる物質です。抗菌剤は抗菌作用または抗生物質作用、抗真菌作用または抗ウイルス作用を持ち、これらの物質のほとんどは天然物であるか、天然物から得られたものです。^{[ 11 ]} したがって、天然物は医薬品の発見に不可欠です。^{[ 50 ] [ 51 ]}天然から得られる抗生物質のほとんどは放線菌門に属する生物によって産生されます。放線菌によって産生される抗生物質物質のほとんどはストレプトマイセス属によるものです。^{[ 52 ] [ 53 ]}抗菌特性を持つこれらの天然物は、テルペノイド、スピロテトロネート、テトラセンジオン、ラクタム、およびその他の化合物群に属します。例としては、ナピラディオマイシン、ノミミシン、フォルミカマイシン、イソイカルガマイシンなどがあります。^{[ 54 ] [ 55 ] [ 56 ] [ 57 ]}一部の金属、特に銅、銀、金は抗菌性も持っています。抗菌銅合金の接触面を使用することは、細菌の伝播を防ぐために21世紀に入ってから使われ始めた技術です。^{[ 58 ] [ 59 ]}銀ナノ粒子も建築物の表面や布地に組み込まれ始めていますが、微粒子が人体に及ぼす潜在的な副作用について懸念が提起されています。^{[ 60 ]}特定の金属が持つ抗菌性のため、医療機器などの製品はそれらの金属を使用して作られています。^{[ 59 ]}

• 微生物の生物地理学
• 微生物ループ
• 生態学の概要
• 国際微生物生態学会
• ISMEジャーナル