席宇《環(huán)境微生物學(xué)》13環(huán)境微生物學(xué)講義-課件3

1、 環(huán)境微生物學(xué) 鄭州大學(xué)生物工程系 席 宇Environmental Microbiology第二章 微生物生態(tài)學(xué)Chapter outline一、概 論二、自然生態(tài)系統(tǒng)中微生物的分布三、微生物之間的相互作用在一定的空間內(nèi)生物的成分和非生物的成分通過物質(zhì)循環(huán)和能量流動互相作用、互相依存而構(gòu)成的一個生態(tài)學(xué)功能單位。生態(tài)系統(tǒng)(ecosystem)：生態(tài)學(xué)(ecology)：研究生物與其周圍生物和非生物環(huán)境之間相互關(guān)系的一門科學(xué)。第一節(jié) 概 論一、基本概念生命科學(xué)研究中，一般可分成十個水平，依次為：生物圈(biosphere)生態(tài)系統(tǒng)(ecosystem)群落(community)種群(popula

2、tion)個體(individual)器官(organ)組織(tissue)細(xì)胞(cell)細(xì)胞器(organelle)分子(molecule)生態(tài)學(xué)范疇the study of microbial relationship with other organisms and also with nonliving environments. These relationships, based on interactive uses of resources, have effects extending to the global scale.Microbial ecologyMethods

3、 used to study microbial interaction and microbial ecology provide information on environmental characteristics; microbial biomass. Numbers, types and activity, and community structure. Microscopic, chemical, enzymatic and molecular techniques are used in these studies.微生物生態(tài)學(xué)(microbial ecology)：研究微生

4、物與其周圍生物和非生物環(huán)境之間相互關(guān)系。 各種環(huán)境中的微生物的種類、分布； 微生物和其它生物的關(guān)系； 微生物與物質(zhì)循環(huán)；Microbial ecology Environmental microbiology? The term microbial ecology is now used in a general way to describe the presence and distributions of microorganisms.Microbial ecology is the the study of the behavior and activities of microorg

5、anisms in their natural environments.Microbial ecologyEnvironmental microbiologyIt is not concerned with the particular micro-environment where the microorganisms actually are functioning, but with the broader-scale effects of microbial presence and activities.Environmental microbiology is relates p

6、rimarily to all over microbial processes that occur in a soil, water or food, as examples二、自然環(huán)境中微生物的生態(tài)學(xué)特點(diǎn)1.微環(huán)境（微生境 microhabitat）微生物個體微小，所處的環(huán)境也微小，肉眼見不到，一般稱為微環(huán)境(microenvironments)。在一個土壤團(tuán)塊內(nèi)或一條植物根的表面，可能存在著許多環(huán)境因素不同的微環(huán)境。每一微環(huán)境中只適宜于某種或某些微生物生長繁殖，從而形成復(fù)雜的微生物區(qū)系(microflora)。 2.表面環(huán)境*與附生環(huán)境中的營養(yǎng)物常吸附于物體表面，所以表面營養(yǎng)水平高，菌

7、數(shù)多。天然水濾去顆粒物，近99的細(xì)菌亦被除去。微生物在物體表面形成生物膜（biofilm,BF），過程如下；(1).有機(jī)質(zhì)附著在物體表面上。(2).附著于表面上的有機(jī)物的化學(xué)信息，誘導(dǎo)微生物向它定向移動進(jìn)而以其一端附著在表面上。(3).吸附在表面上的微生物分泌出胞外聚合物，菌體與物體表面粘著在一起，形成牢固吸附層。表面吸附的微生物數(shù)往往比水體中高幾十倍到幾百倍。3.寡營養(yǎng) 自然界營養(yǎng)水平往往只有1mgCL-10mgCL或更低，與培養(yǎng)基中的有機(jī)物水平約1gCL-10gCL相比是很低的。所以在自然狀態(tài)下生活的微生物常處于營養(yǎng)貧乏的狀況無毒的有機(jī)污染物進(jìn)入土壤或水體，可引起微生物數(shù)量劇增能在1mgC

8、L-15mgCL低含量有機(jī)質(zhì)培養(yǎng)基中生長的細(xì)菌,謂寡(或貧)營養(yǎng)細(xì)菌(oligotrophic bacteria)，它們在去除痕量有機(jī)污染物方面具有應(yīng)用潛力。4.生長緩慢在自然界中微生物很少有對數(shù)生長期，生長很緩慢。如E.coli在肉湯中的代時為20min左右，在人腸道中為12h；而牧場土壤中的細(xì)菌，代時可長達(dá)1200h。在實驗室里研究天然微生物生態(tài)系統(tǒng)的適宜模型是恒化器(chemostat)*。自然環(huán)境中的微生物一般都不是單獨(dú)存在的個體、種群、群落和生態(tài)系統(tǒng)從低到高的組織層次種群（population）：具有相似特性和生活在一定空間內(nèi)的同種個 體群，是組成群落的基本組分。群落（communi

9、ty）：在一定區(qū)域或一定生態(tài)環(huán)境內(nèi)，各種生物 群體構(gòu)成的一個生態(tài)學(xué)結(jié)構(gòu)單位，群落中 各生物群體之間存在各種相互作用。第二節(jié) 自然生態(tài)系統(tǒng)中微生物的分布生物圈（biosphere）：地球上所有生物及其所生活的非生命環(huán)境 的總稱。個體群體群落+非生物環(huán)境生態(tài)系統(tǒng)生物圈任何一個相對完整的自然整體都可以被看作為一個生態(tài)系統(tǒng)，如一個池塘，一片森林，一個污水處理池，等等。PopulationsGuildsCommunitiesEcosystemMicroorganisms and MicroenvironmentMetabolically related populations constitute gr

10、oupings called guilds.Sets of guilds conducting complementary physiological processes interact to form microbial communities.In a microbial ecosystem individual cells grow to form populations.Community 3Microbial communities then interact with communities of microorganisms to define the entire ecosy

11、stem.EcosystemA Simple EcosystemAn alga,which releases photosynthetically generated oxygen and organic matter to its enviroment ,is surrounded by chemoheterotrophs that are using these products of primary production.Microorganisms in NatureDistribution of microorganisms In:SoilWaterAirFoodWith plant

12、s and animalsTerrestrial EnvironmentsThe distribution of microorganisms in nature ecosystem depends on the resources (nutrients) available and on the growth conditions. Temperature, pH, water availability, light, oxygen of a habitat define the niche for each particular microorganism. Soil particles

13、are not homogeneous in terms of their oxygen content. The outer zones of a small soil particle may be fully oxic, whereas the center, only a very short distance away, can remain completely anoxic. A soil aggregate composed of mineral and organic components, showing that localization of soil microbes

14、. Very few microorganisms are found free in the soil solution; most of them occur as microcolonies attached to the soil particles.Proportion of different soil microorganisms in soilMicrobosNumber /gBiomass(g/m3) Bacteria108160Fungi105200Actinomycets105 - 106160Algae104 - 10532Protozoa10438Microbial

15、number and biomass in cultivated field soil（15 cm）AgrobacteriumAlcaligenesArthrobacterBacillusCaulobacterCellulomonasClostridiumCorynebacteriumFlavobacteriumMicrococcusMycobacteriumPseudomonasStaphylococcusMain types of soil microorganismsThe rhizosphere is the soil region in close contact with plan

16、t roots.Rhizosphere Effect ( R/S ratio )根 圈 效 應(yīng) （根土比）Within the rhizosphere, the plant roots exert a direct influence on the soil bacteria. This influence is known as the rhizosphere effect.In the rhizosphere, microbial populations reach much higher densities in the rhizosphere than in the free soil

17、. Microbial populations in the rhizosphere may benefit the plant by:increasing solubilization of mineral nutrients needed by the plant for growth synthesizing vitamins, amino acids, auxins, gibberellins that stimulate plant growthantagonizing potential plant pathogens through competition and the pro

18、duction of antibiotics removing hydrogen sulfide, which is toxic to the plant rootsFreshwater EnvironmentsTypical aquatic environments are the oceans, estuaries, salt marshes, lakes, ponds, rivers, and springs. Aquatic environments differ considerably in chemical and physical properties, and their m

19、icrobial species compositions also differ. Marine Environments Much of the primary productivity occur in the open oceans Inshore ocean areas are typically more nutritionally fertile and therefore support more dense populations of phytoplanktonIn the oceans primary productivity is rather low 第三節(jié) 微生物與

20、生物環(huán)境間的關(guān)系生態(tài)系統(tǒng)中生物之間的相互關(guān)系： 有利關(guān)系：一種生物的生長和代謝對另一種生物的生長產(chǎn)生有利的影響，或相互有利； 有害關(guān)系：一種生物的生長對另一種生物的生長產(chǎn)生有害的影響，或相互有害； 中性關(guān)系：二種生物生活在一起時，彼此對對方的生長代謝無明顯的有利或有害影響；動物間的關(guān)系植物間的關(guān)系動植物間的關(guān)系狼狽為奸日本人的生意經(jīng)相生相克情花之毒與斷腸草花和蜘蛛合作吃人微生物生態(tài)的研究特點(diǎn)：以微生物群體，即種群作為主要研究單位。Commensalism（偏利）Synergism（互生） Mutualism（共生）Competition（競爭）Antagonism（拮抗）Parasitism（

21、寄生）Predation（捕食）Microbial population interactionsNeutralism(中立) there is no any physiological effect between the populations.Commensalism（偏利） Commensalism is a unidirectional relationship betwen populations in which one population benefits and the other one is unaffected.Synergism（互生） Synergism indi

22、cates that both populations benefit from the relationship but the association is not obligatory. Both populations are capable of surviving independently.Mutualism Symbiosis（互利共生） Mutualism Symbiosis is an obligatory inter- relationship between two populations that benefits both of them. Lichens is c

23、omposed of a fungus and an alga.Competition（競爭） Competition occurs when two populations are striving for the same resource of nutrients or the habitat.Antagonism（拮抗） Antagonism occurs when one population produces a substrate inhibitory to another population.Parasitism（寄生） the parasite population is

24、benefited and the host population is harmed. Predation is a widespread phenomenon where the predator engulfs or attacks the prey. The predator can be larger or smaller than the prey, and this normal results in the death of the prey. Predation（捕食）Classification of population interaction0:No effect; +

25、: positive effect; -: negative effect. NAME OF INTERACTION POPULATION A POPULATION BNeutralismCommensalismSynergismMutualismCompetitionParasitismPredation 0 0 + + - + + 0 + + + - - -EFFECT OF INTERACTION微生物間及與其它生物間相互關(guān)系：一、互生(syntrophism; protocooperation)二種可以單獨(dú)生活的生物，當(dāng)它們生活在一起時，通過各自的代謝活動而有利于對方，或偏利于一方的一

26、種生活方式,又稱原始的共生關(guān)系?！翱煞挚珊?，合比分好”一）微生物間的互生關(guān)系纖維素分解細(xì)菌固氮菌金黃色葡萄球菌的生長為本來在平板上不能生長的嗜血流感菌提供生長因子，后者在其菌苔周圍形成衛(wèi)星菌落。本來不能在含青霉素的平板上生長的受體菌在轉(zhuǎn)化子（含有Ampr質(zhì)粒）周圍形成衛(wèi)星菌落（b-內(nèi)酰胺酶分泌到胞外所致）二）人體腸道正常菌群互生關(guān)系（正常情況）寄生關(guān)系（某些特殊條件下）人腸道內(nèi)的菌群：60-400種不同的微生物，占糞便干重的1/3是細(xì)菌，其中厭氧菌占了絕大多數(shù)。 正常菌群通過腸道獲取營養(yǎng)； 通過排阻、抑制外來致病菌；提供許多人一定程度的固氮作用體所必不可少的維生素、氨基 酸等營養(yǎng)物對人體作出貢

27、獻(xiàn)；環(huán)境條件改變或著生部位改變：正常菌群致病菌 濫用抗生素； 人身體虛弱抵抗力下降； 吃了不潔凈的食物；腸道中的正常菌群，大腸桿菌，一旦進(jìn)入泌尿系統(tǒng)，引起尿路感染。人體表面的正常菌群，一旦它們進(jìn)入傷口也會引起感染。條件致病菌：人體的正常微生物菌群一旦進(jìn)入非正常聚居部位， 或生態(tài)結(jié)構(gòu)發(fā)生改變而引起人類疾病的微生物。可以通過口服某些活的微生物制劑來治療由于正常菌群失調(diào)而導(dǎo)致的腹瀉。含蠟狀芽孢桿菌（B cereus）的“促菌生”，含地衣芽孢桿菌的“整腸生”等，它們都是通過芽孢桿菌的生長，為腸道重新創(chuàng)造良好的厭氧環(huán)境，促使腸道內(nèi)正常的厭氧菌的生長繁殖，這類活微生物制劑又稱微生態(tài)制劑。二、共生（symb

28、iosis）二種生物共居在一起，相互分工協(xié)作、相依為命，甚至形成在生理上表現(xiàn)出一定的分工，在組織和形態(tài)上產(chǎn)生了新的結(jié)構(gòu)的特殊的共生體?；セ莨采憾呔美采阂环降美?，但另一方并不受害一）微生物間的共生關(guān)系地衣-藻類和真菌的共生體形成有固定形態(tài)的葉狀結(jié)構(gòu)：真菌無規(guī)則地纏繞藻類細(xì)胞，或二者組成一定的層次排列。地衣繁殖時，在表面上生出球狀粉芽，粉芽中含有少量的藻類細(xì)胞和真菌菌絲，粉芽脫離母體散布到適宜的環(huán)境中，發(fā)育成新的地衣結(jié)構(gòu)上的共生：生理上的共生：共生菌從基質(zhì)中吸收水分和無機(jī)養(yǎng)料；共生藻進(jìn)行光合作用，合成有機(jī)物； 使地衣能在十分貧瘠的環(huán)境中生存。二）微生物和植物間的共生關(guān)系根瘤菌與豆科植物間的共生-形成根瘤共生體 根瘤菌固定大氣中的氣態(tài)氮為植物提供 氮素養(yǎng)料； 豆科植物的根的分泌物能刺激根瘤菌的生 長，同時，還為根瘤菌提供保護(hù)和穩(wěn)定 的生長條件。 反芻動物，如牛、羊、駱駝、長頸鹿等以植物的纖維素為主要 食物，它們在瘤胃中經(jīng)微生物發(fā)酵變成有機(jī)酸和菌體蛋白再