Name: measuring microbial diversity and activity
Uploaded: 2026-03-12T13:57:42.000Z
Duration: 1 min 19 s
Channel: JoVE

미생물 군집은 박테리아, 고세균, 미생물 진핵생물이 공존하며 공유된 서식지 내에서 상호작용하는 컨소시엄입니다.미생물 군집 구조는 풍부도, 상대적 개체 수, 균일성을 통해 자주 설명됩니다.표본에서 풍부도는 검출된 분류군의 수를 의미하며, 상대적 풍부도는 각 분류군의 비율을 정량화합니다. 균등성은 개체가 분류군 간에 얼마나 균일하게 분포되어 있는지를 설명합니다.현재는 배양 독립적 분자 접근법을 사용하여 미생물 군집을 프로파일링하고 있습니다.메타게놈학은 토양과 같은 환경 샘플에서 DNA를 연구하며, 주로 미생물 군집 구성을 프로파일링하는 데 사용됩니다.메타전사체학은 mRNA 발현을 평가하여 효소 생성이나 오일 분해와 같은 활성 미생물 기능을 파악할 수 있게 합니다.메타프로테오믹스와 대사체학은 환경 내 단백질과 대사산물을 식별하여 미생물이 영양분 분해와 생지구화학적 순환 같은 과정에 어떻게 기여하는지 밝혀냅니다.

미생물 군집 평가 방법

Methods to Assess Microbial Communities

박테리아, 고세균, 진핵생물 등 미생물 군집은 다양한 생태계에 서식하며 환경 및 생물학적 과정에서 중요한 역할을 합니다. 이들의 다양성은 세 가지 주요 지표로 정의됩니다: 종의 풍부도 (구별되는 종의 수), 종 풍부 도(각 종의 상대적 수), 그리고 종의 균등성 (개별 종이 여러 지역에 얼마나 균등하게 분포하는지). 이 요소들은 함께 군집의 구조와 생태적 균형을 형성합니다.<h3>미생물 다양성 정량화</h3>미생물 다양성을 평가하기 위해 과학자들은 수학적 지수를 사용합니다. 섀넌 지수는 풍부도와 균일성을 모두 반영하며, 값이 높을수록 다양성과 균형이 더 클 수 있습니다. 심슨 지수는 표본에서 무작위로 선정된 두 개체가 같은 종에 속할 확률을 측정합니다; 심슨 값이 낮으면 종의 우세가 줄어들어 더 높은 다양성을 시사합니다. 이 지수는 지역사회 건강과 생태계 안정성을 평가하는 데 도움을 줍니다.<h3>문화 기반 및 문화 독립적 방법</h3>미생물 군집은 실험실 배양에 의존하는 배양 의존 적 방법으로 조사할 수 있습니다. 하지만 많은 미생물은 표준 조건에서는 배양이 불가능하여 이 접근법이 제한됩니다. 반면, 배양 독립 기법은 환경 샘플에서 직접 미생물을 분석하여 미생물 다양성과 기능을 보다 포괄적으로 평가할 수 있게 합니다.<h3>분자적 접근법 - 군집 평가</h3><ul><li>메타게놈학: 이 기술은 환경 샘플에서 유전체 DNA를 서열 분석합니다. 이 연구는 미생물 분류군을 식별하고, 배양 불가능하거나 희귀한 생물을 포함한 군집의 유전적 잠재력을 밝혀냅니다.</li><li>메타전사체학: mRNA를 시퀀싱하여 어떤 유전자가 적극적으로 전사되고 있는지 확인합니다. 이는 지역사회 내에서 진행 중인 대사 활동의 기능적 스냅샷을 제공합니다.</li><li>메타프로테오믹스: 이 접근법은 환경 샘플 내 모든 단백질을 분석합니다. 합성되는 단백질을 밝혀내어 활성 대사 경로와 생리적 과정에 대한 통찰을 제공합니다.</li><li>대사체학: 이 기술은 미생물 활동의 최종 산물인 소분자 대사산물을 프로파일링합니다. 이 대사산물은 생리적 상태와 미생물 간 상호작용을 반영하여 영양 순환과 환경 스트레스 반응 같은 과정을 설명하는 데 도움을 줍니다.</li></ul>이러한 방법들은 사용 가능한 도구의 일부에 불과하며; 다양한 기법을 통합하면 미생물의 다양성, 기능, 생태계 복잡성에 대한 이해가 향상됩니다.

Microbial communities, comprising bacteria, archaea, and eukaryotic microorganisms, inhabit diverse ecosystems and play crucial roles in environmental and ...

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Education

교육

JoVE Core

Microbiology

미생물학

Unit

단위

Microbial Ecology

미생물 생태학

KEY TERMS AND CONCEPTS

주요 용어 및 개념

measuring microbial diversity and activity

Microbial communities include bacteria, archaea, and eukaryotic microorganisms. They live in many ecosystems and affect important environmental and biological processes. Scientists study these communities by looking at how many species are present, how many individuals each species has, and how evenly the species are spread out.

Species richness is the number of different species in a sample. Species abundance is the relative amount of each species. Species evenness describes how uniformly the individuals are distributed among species. Together, these measures help show the structure and ecological balance of a microbial community.

Researchers also use diversity indices to quantify microbial communities. The Shannon index includes both richness and evenness, and higher values show greater diversity and balance. The Simpson index measures the chance that two randomly chosen individuals belong to the same species. Lower Simpson values indicate higher diversity because no single species dominates as much.

Microbial communities can be studied with culture-based methods or with culture-independent methods. Culture-based methods depend on growing microbes in the lab. This approach has limits because many microbes cannot be cultured under standard conditions. Culture-independent methods examine microbes directly from environmental samples and can give a broader view of diversity and function.

Several molecular methods are used in culture-independent analysis. Metagenomics sequences genomic DNA from environmental samples to identify microbial taxa and reveal the genetic potential of the community, including rare or unculturable organisms. Metatranscriptomics sequences mRNA to show which genes are actively being transcribed, so it gives a snapshot of ongoing metabolic activity.

Other methods add more detail about community function. Metaproteomics analyzes all proteins in a sample and shows which proteins are being made. This helps reveal active metabolic pathways and physiological processes. Metabolomics profiles small-molecule metabolites, which are the end-products of microbial activity. These metabolites can reflect physiological state, microbial interactions, nutrient cycling, and responses to environmental stress.

Together, these tools give scientists a fuller picture of microbial diversity and ecosystem complexity. Using more than one method can improve understanding of both who is there and what they are doing in the community.

Measuring Microbial Diversity and Activity

measuring-microbial-diversity-and-activity

introduction to microbial ecology

Microbial Communities in Soil and Extremes

Microbial ecology looks at how microorganisms live, interact, and adapt in different ecosystems. It also shows how these tiny organisms help shape nutrient cycling, energy flow, and environmental balance. An ecosystem includes living parts and non-living parts, and microbes respond to both. Microorganisms can form populations, which are groups of the same species living together at the same time. When populations from different species live and interact in the same place, they form a microbial...

ecological niche

Microbial Niches in Ecosystems

Microbial niches describe how microorganisms survive, grow, and interact in an ecosystem. A niche includes how a microbe gets resources, reproduces, and relates to other species in its environment. This idea helps explain microbial community dynamics, biogeography, and ecosystem function. A microorganism’s fundamental niche is the full range of conditions where it could survive, grow, and reproduce. These conditions include both biotic factors, such as living interactions, and abiotic factors,...

methods to assess microbial populations

Measuring Microbes in Samples

Measuring microbes in a sample helps scientists study health, ecology, and industry. Microbial counts can show how many cells are present, how diverse they are, and what they may be doing. To do this, researchers use both culture-based and molecular methods. A viable plate count is a classic culture method for estimating living microbes. The sample is first diluted step by step, then spread on nutrient agar plates. Each viable cell can grow into a visible colony, so the colonies can be counted.

methods to assess microbial communities

Microbial communities include bacteria, archaea, and eukaryotic microorganisms. They live in many ecosystems and affect important environmental and biological processes. Scientists study these communities by looking at how many species are present, how many individuals each species has, and how evenly the species are spread out. Species richness is the number of different species in a sample. Species abundance is the relative amount of each species. Species evenness describes how uniformly the...

the winogradsky column

Microbial Layers Inside a Winogradsky Column

A Winogradsky column shows how microbial layers form in a simple, sealed ecosystem. It is a clear model for studying microbial ecology and how different metabolisms interact in sediment over time. The setup uses a transparent glass cylinder. Half of it is filled with sediment mixed with cellulose, such as shredded paper, calcium carbonate, and gypsum. The cellulose provides a carbon source. Calcium carbonate buffers pH, and gypsum supplies sulfate. The rest of the cylinder is filled with pond...

microenvironments

Microbial Niches in Tiny Habitats

Microorganisms live in tiny habitats called microenvironments. These spaces have their own physical and chemical conditions. Oxygen level, pH, temperature, light, and nutrient supply can all differ from the surrounding area. These local conditions strongly affect microbial growth, metabolism, and which species can live there. Microenvironments often have sharp gradients over very small distances. In soil, oxygen may be available at the particle surface but drop off just a few millimeters below.

microbial mats

Microbial Mats and Oxygen Gradients

Microbial mats are layered communities of microbes that grow in response to changes in light, oxygen, and nutrients. These ecosystems are highly organized, and different microorganisms live at different depths. Biofilms are the early stage of this growth and are only a few millimeters thick. Mature microbial mats can grow to centimeter scale and show clear vertical structure. This layered arrangement lets microbes fill separate niches within a very small space. In cyanobacterial mats from hot...

microbial interactions: mutualism

Mutualistic Partnerships in Nature

Mutualistic partnerships in nature show how two or more organisms can benefit from living together. These symbiotic relationships can be obligate, meaning the partners depend on each other, or facultative, meaning the association is helpful but not required. Mutualism helps support many ecosystem functions across land and water. One common example is the partnership between plant roots and mycorrhizal fungi, such as Rhizophagus species. The fungal hyphae grow into the root hairs and epidermis,...

microbial interactions: cooperation

Microbial Cooperation in Soil and Hosts

Microbial cooperation describes helpful interactions between different species. In these partnerships, microbes work together for one or mutual benefit. These interactions can shape ecosystems and evolution. They also play major roles in symbiosis and disease. One clear example involves the Gram-negative bacterium Xenorhabdus nematophila and the parasitic nematode Steinernema carpocapsae. Juvenile nematodes carry the bacteria in the soil and need an insect host to mature. When the nematode...

microbial interactions: predation

How Microbes Hunt and Defend

Microbial predation is a form of interaction in which one microorganism kills and eats another to gain nutrients and energy. It includes both bacterial predators and protozoan predators. This process helps shape microbial communities and affects how nutrients move through the environment. Some bacterial predators attack from the outside, while others enter the prey cell. Epibiotic predators, such as Vampirococcus, attach to the surface of a prey cell and release hydrolytic enzymes. These...

microbial interactions: competition

Microbial Competition and Niche Partitioning

Microbial competition shapes how bacteria and other microbes share space and resources. In shared environments, they compete for nutrients, space, or light. The strength of this competition depends on the environment, including nutrient levels, space limits, and how many microbial species are present. These interactions help determine the structure, function, and resilience of microbial communities. Microbial competition is usually grouped into exploitative competition and interference...

microbial interactions: parasitism

Microbial Parasites and Host Dependence

Microbial parasites depend on a host for nutrients and shelter, and this dependence often harms the host. In parasitism, only the parasite benefits. This is different from mutualism, where both organisms gain from the relationship. Microbial parasites are classified by where they live in or on the host. Ectoparasites stay on the host’s surface, such as the skin or outer tissues, and take in nutrients from outside. Endoparasites live inside the host’s body and invade tissues or organs.

microbe-plant interactions

How Plant Microbes Affect Growth

Plant microbes can help, harm, or simply live alongside their hosts. These microbe-plant interactions shape plant growth, health, and ecosystem function. The plant microbiome includes bacteria, fungi, archaea, protists, and viruses, and these organisms may live on the plant surface, inside plant tissues, or in symbiosis throughout the plant. Some of the most important beneficial partnerships involve mycorrhizal fungi. These fungi form close connections with roots and are grouped as arbuscular...

microbes and the carbon cycle

How Microbes Move Carbon Through Earth

Microbes move carbon through Earth’s major reservoirs and help drive the carbon cycle. Carbon shifts among the biosphere, lithosphere, atmosphere, and hydrosphere, where it supports life and helps regulate climate. It commonly cycles as carbon dioxide (CO2), the oxidized form of carbon, but methane (CH4) and organic compounds also matter. Photosynthetic microbes take in atmospheric CO2 and turn it into organic carbon. Cyanobacteria are especially important because they carry out oxygenic...

microbes and methanogenesis

How Microbes Produce Methane

Methane production in anaerobic ecosystems depends on methanogenic archaea and the microbes that work with them. This process happens where oxygen is absent, such as wetlands, sediments, and animal gastrointestinal tracts. In these anoxic habitats, aerobic respiration cannot run, so microbes use other pathways to break down organic matter. Anaerobic decomposition starts when cellulolytic bacteria, or cellulose-digesting bacteria, hydrolyze dead organic material into simple sugars. Other...

microbes and the nitrogen cycle

Microbial Steps in the Nitrogen Cycle

Microbes drive the nitrogen cycle by changing nitrogen into forms that plants and other organisms can use. This biogeochemical cycle keeps nitrogenous compounds balanced in ecosystems. It also supports plant growth and microbial growth. Nitrogen fixation begins the cycle by converting inert atmospheric nitrogen gas, N2, into ammonia, NH3. This step depends on nitrogenase enzymes. Free-living diazotrophs do this on their own. Aerobic bacteria such as Azotobacter spp. and anaerobic bacteria such...

microbes and the sulfur cycle

Sulfur Cycling Through Microbial Reactions

Sulfur cycling depends on microbial reactions that move sulfur through rocks, water, soil, and the air. In Earth systems, sulfur shifts among inorganic forms such as sulfate, elemental sulfur, and sulfide. These changes happen through both abiotic processes and biological activity in oxic and anoxic environments. Sulfate is the most oxidized form of sulfur. It is stored mainly in rocks, marine sediments, and ocean water, where it acts as a long-term reservoir in the global sulfur cycle. In...

microbes and other elemental cycles

Microbes Driving Iron and Manganese Cycles

Microbes drive iron and manganese cycling in aquatic environments by changing these metals between reduced and oxidized forms. These reactions are especially important along redox gradients, where oxygen levels shift across stratified water layers. The microbes use these metals for energy, growth, and structural needs. In oxygen-rich surface waters, iron is usually present as insoluble ferric iron, Fe(III). Some bacteria release siderophores, which are small organic molecules that bind ferric...

marine microbial ecology

Microbial Life in the Ocean

Marine microbial life is shaped by salinity, low nutrients, and changing oxygen levels. These physical and chemical limits influence which microbes can survive and how they function. They also affect how ocean microbes help drive nutrient and carbon cycling. Small cell size is common in these environments because it gives microbes a larger surface-to-volume ratio. That helps them take up nutrients more efficiently when nutrients are scarce. In estuaries, where salinity changes often,...

deep sea microbial ecology

Deep Sea Microbes and Extreme Conditions

Deep sea microbes live in one of Earth’s harshest environments. The deep ocean is far below the sunlit photic zone, which usually reaches the upper 100 to 200 meters of open water. Below that layer, the bathypelagic and abyssal zones stretch from about 1,000 to 6,000 meters, and hadal trenches go even deeper. This region is dark, cold, and highly pressurized. Temperatures are usually around 2 to 3°C, although hydrothermal vents can be slightly warmer. Pressure rises by about 1 atmosphere for...

freshwater microbial ecology

Microbes in Streams, Lakes, and Rivers

Freshwater microbes live in streams, rivers, lakes, ponds, and marshes, but their communities change with water movement, light, depth, and nutrients. These systems are often grouped into lotic waters, which flow, and lentic waters, which are still or slow-moving. The physical setting shapes where microbes grow and how they get energy. In lentic systems, phytoplankton are the main producers. They make autochthonous organic carbon, which means carbon made within the water body. In lotic...

soil microbial ecology

How Soil Microbes Cycle Nutrients

Soil microbes drive nutrient cycling, organic matter turnover, and ecosystem stability. A gram of soil can contain thousands of bacterial and archaeal taxa, but their shared job is what helps sustain land ecosystems. Their activity changes the way carbon, nitrogen, and other nutrients move through soil. Soil is a patchwork of minerals, organic matter, water, and air. Microbes live in tiny microhabitats shaped by pore size, moisture, oxygen, and nutrients. Sandy soils drain fast and tend to...

key terms and concepts

Learn how scientists assess microbial communities using richness, evenness, Shannon and Simpson indices, plus metagenomics, transcriptomics, proteomics, and metabolomics.

Measuring Microbial Diversity and Activity | JoVE K12

JoVE Core Microbiology provides an engaging introduction to the microbial world and its influence on health, industry, and the environment. This comprehensive collection covers key concepts such as microbial structure, metabolism, genetics, and ecology. It introduces essential laboratory techniques and microscopy methods through visually engaging animations. Corresponding scientist-in-action videos bridge classroom concepts with real-world research and applications.

microbiology

Measuring Microbial Diversity and Activity

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