微生物學(xué)筆記(武漢大學(xué))2（Notes on Microbiology (Wuhan University) 2）

1、微生物學(xué)筆記(武漢大學(xué))2（Notes on Microbiology (Wuhan University) 2）Notes on Microbiology (Wuhan University) 2The mode of propagation of fungi:1) asexual spore propagationThe process of forming new individuals without vegetative cell differentiation is the division of vegetative cells or the differentiation (c

2、leavage) of vegetative hyphae.The asexual spores are: spores, spores, conidia, spores, etc.2) sexual spore propagationTwo the process by which individual cells combine to produce new individuals:A) disposition: two individual cells bind to cytoplasm and become binuclear cells. Each nucleus contains

3、haploid chromosomes (n+n).B) nuclear fusion: the fusion of two nuclei into diploid zygote nuclei, at which time the number of chromosomes is two times (2n).C) meiosis: the nucleus of a diploid body passes through meiosis, and the number of chromosomes in the nucleus is restored to a haploid state.Ch

4、aracteristics of sexual spore propagation in fungi:A is not as good as asexual reproduction, then often associated with common, more natural conditions, in generalNot common on the culture medium.B) the method varies according to the strain, and some two vegetative hyphae can be directly combined,Ot

5、hers are mated by special sex cells (sexual organs) to form sexual spores.(c) nuclear division immediately after meiosis, so the number of chromosomes is haploid,The diploid is restricted to the zygote.D) mold of sexual reproduction is homothallism and heterothallism in two cases.(E) the sexual spor

6、es of fungi, including spores, eggs, spores, and spores.Life cycle of fungi:During asexual propagation, asexual spores are formed in the mycelium (vegetative body) under suitable conditions, and asexual spores germinate to form new hyphae, repeated many times.The stage of sexual reproduction; in the

7、 late stage of development, under certain conditions, a special organ differentiation on the mycelium (cell), plasmogamy, nuclear distribution, after meiosis forming haploid spores germination, then form new mycelium.There are some fungi, as has been found to sexual reproduction stage in its life hi

8、story, this kind of fungus called deuteromycetes.Characteristics of mold spores:Mold has a strong reproductive capacity, and can produce large numbers of new individuals through asexual reproduction or sexual reproduction. Although the hyphae of the mycelium take on part of their hyphae to reproduce

9、, they also propagate mainly in a variety of asexual or sexual spores under normal natural conditions.The spores of fungi have the characteristics of small, light, dry, many, as well as different shape, color, long dormancy and strong stress resistance. But there is a big difference between bacteria

10、 and spores. The spore morphology of fungi is usually spherical, oval, oval, hat shaped, Saturn shaped, kidney shaped, linear, sickle shaped, etc. The number of spores produced by each individual, often tens of thousands of, sometimes even reach tens of billions, hundreds of billions of dollars or m

11、ore. These characteristics of spores,Both help spread and multiply fungi in nature.For human practice, these characteristics of spores are beneficial for inoculation, extended culture, strain selection, preservation and identification. Disadvantages to humans are fungal diseases that are prone to po

12、llution, mildew, and the spread of animal and plant diseases.Comparison of fungal spores and bacterial sporesMould spore bacteria sporeSizeThe number of hyphae or a cell yields 1 cells, producing only 1The morphology, morphology and color are various, and the shape is simpleThe site of formation can

13、 be formed in or outside the cell, only in cellsEukaryotic cell nucleusThe most important mode of reproduction is not reproduction, but resistance (dormancy)Heat resistance is not strong, easily killed at 60-70 degrees, very strong, generally 100 minutes Celsius to killMost bacteria produce a small

14、number of bacteria that produce themYeast colonies: similar to bacterial colonies, but generally larger than bacterial colonies and thick, surface moist, sticky, easy to stir up, mostly milky white, and a few red.Distribution of yeasts and their relationship with humans:1 and more are distributed in

15、 sugar containing acid environment, also known as sugar bacteria. 2 important microbial resources;3 important scientific research models: 4. Some yeasts are harmful;The breeding and life cycle of yeasts:1. Asexual propagation1): the main way of asexual budding, mature cells grow a small bud, to cont

16、inue to grow the new individual from a certain degree of maternal.2) fission: a small number of yeasts, like bacteria, can reproduce by cutting across cells, such as fission yeast.2, sexual reproductionYeast develops sexually in the form of a sac and spore:1) two haploid cells of different sex are c

17、lose to each other and contact each other;2) the cell wall disappears at contact and matches with each other;3) nuclear matching, forming diploid nuclear zygote:A, vegetative growth, reproduction, and independent living in a diploid manner;Meiosis is performed before the next sexual reproduction.B a

18、nd undergo meiosis to form 4 or 8 conidia, whereas the original nutrients are presentThe cell becomes a sac. Spores germinate and form haploid vegetative cells.3, life historyYeast, haploid, and diploid cells are independent of each other. There are three types:1) the vegetative body can only be pre

19、sent in haploid form (immediately after nuclear division)2) the vegetative body can only exist in diploid form (not immediately after nuclear division)3) the vegetative body can be either haploid or diploid,Budding propagation can be carried out.Yeast has not yet been found in its sexual stage, know

20、n as CandidaMicrobial nutrient types:1. light energy autotrophic (light autotrophic) can take CO2 as the main single or major carbon source, and the energy needed for photosynthesis to obtain growth;Inorganic compounds such as H2, H2S and S are used as hydrogen donors or electron donors to restore C

21、O2 to cell substance;For example, algae and cyanobacteria, like plants, use water as an electron donor (hydrogen donor) to produce oxygen based photosynthesis and synthesize cell substances. Red sulfur bacteria take H2S as electron donor to produce cell substances and accompany with the generation o

22、f sulfur.2. light energy, organic heterotrophic type (light energy heterotrophic)CO2 can not be the main or only carbon source. When organic matter is used as hydrogen donor, CO2 can be reduced to cell substance by light energy. Most of the growth requires exogenous growth factors;For example, some

23、bacteria in the genus using isopropanol as the hydrogen donor, the reduction of CO2 to cell material, while the accumulation of acetone.3. can be inorganic autotrophic type (autotrophic type)The energy needed for growth comes from the chemical energy released by the oxidation of inorganic substances

24、;When CO2 or carbonate is used as the sole or major carbon source for growth, CO2, such as H2, H2S, Fe2+, NH3 or NO2-, is used as an electron donor to restore the cell into a cell substance.4. can be organic, heterotrophic, or heterotrophicThe energy required for growth is derived from the chemical

25、energy released by organic matter during oxidation;The carbon sources needed for growth are mainly organic compounds such as starch, sugars, cellulose, organic acids, etc.Oxidation-reduction potential: also known as redox potential (redox, potential), is a measure of a redox systemAn indicator in wh

26、ich an electron or oxidant is released from an electron and the unit is V (V) or mV (MV).The medium should be made from inexpensive and readily available raw materials as medium components, especially in the fermentation industry to reduce production costs.Coarse to fine: for microorganisms, a varie

27、ty of raw materials, nutrition more complete, better effect. And economically, too.Wild generation home: wild plant materials instead of cultivation of plant raw materials, such as cassava, acorns, potato and so on, are rich in starch wild plants, can partially replace grain for industrial fermentat

28、ion of carbon sources.Take waste as a substitute: in the industrial and agricultural production, easy to pollute the environment waste as the raw material for the cultivation of microorganisms. For example, in the process of industrial production of microbial single cell protein, often using molasse

29、s (sugar industry wastewater containing sucrose), whey (from the dairy industry contains lactose), soy products and industrial waste liquor (black papermaking industry containing pentose and hexose sulfite pulp) can be used as a culture medium the raw material. In another case,Industrial methane fer

30、mentation mainly uses waste water and waste residue as raw materials, while in Chinas rural areas, it has been promoted to produce methane as fuel by using human and livestock manure and grass as raw material. In addition, a large number of agricultural and sideline products or products, such as whe

31、at bran, rice bran, corn syrup, yeast extract, lees, bean cake, peanut cake, peptone is commonly used in industrial fermentation of raw materials.In order to simplify the generation: when improving the composition of the medium in the production, the add method is generally used, which means to make

32、 it more and more nutritious, higher and higher content. This is not always beneficial to microbial growth, sometimes try to use the reduction method, a few medium with thin medium components or less to replace the original composition of culture medium, in order to achieve better results.The hydroc

33、arbon generation of food: a by-product of oil or natural gas instead of raw material to cultivate microorganisms. In addition to the production of protein and oil, petroleum products can also be transformed into some higher value of higher alcohols, fatty acids, naphthenic acid and other chemical pr

34、oducts and some compounds, and to improve the quality of petroleum products, such as desulfurization, dewaxing etc.The fiber sugar: the development and utilization of renewable resources in the world, the most abundant cellulose content. A large number of cellulose agricultural and sideline products

35、 will be converted into high-quality feed, industrial fermentation raw materials, fuel and human food and beverages.With inorganic nitrogen generation of protein: on atmospheric nitrogen, ammonium, nitrate or urea as a kind of non protein amino acids or non cheap raw materials used as fermentation m

36、aterial, make into microbial protein or nitrogen containing fermentation products for people to use. Font sizeFifth chaptersComparison of combustion and biological oxidation:Comparison project combustion biological oxidationA sequence of reactions; a rapid step by step reaction; a strict series of r

37、eactionsConditions are intense and are mild by enzymatic catalysisProduction form of heat, Everbright part of ATPLow utilization rate of energyThe form of biological oxidation involves the combination of a substance with oxygen, dehydrogenation, or the removal of electrons from three species;The bio

38、logical oxidation function has three kinds of production capacity (ATP), yield force H and small molecule intermediate metabolite;The fundamental difference between respiration and fermentation: the electronic carrier is not directly transferred to the intermediate product of the electronic substrat

39、e degradation, but to the electronic transfer system, gradually release the energy and then handed over to the final electron acceptor.For nitrate respiration (which can make the nitrate reducing bacteria) known as nitrate reducing bacteria, mainly live in the soil and water environment, among them

40、Pseudomonas, yoriuji Spirillum nitrogen and Micrococcus. In the soil and water environment, the respiration of aerobic organisms, oxygen is consumed by the local anaerobic environment, if nitrate in the environment, nitrate reducing bacteria can live through anaerobic respiration, but if under aerob

41、ic conditions, these bacteria are life - by oxygen the presence of oxygen breathing can inhibit the nitrate reductase activity in the cell membrane. These bacteria are also commonly facultative anaerobes.Denitrification of nitrate reducing bacteria plays an important role in agricultural production

42、and recycling of the earths material:1) denitrification can reduce the nitrogen (nitrate, NO3-) which can be used by plants in the soil to nitrogen, and thus reduce the fertility of the soil, which is unfavorable to agricultural production. One of the effective ways to overcome the denitrification i

43、s to loosen the soil, to keep the soil loose, to remove too much water, and to ensure good aeration in the soil2) denitrification plays an important role in the nitrogen cycle. Nitrate is a substance that readily dissolves in water and usually flows into the water from the soil through water. Withou

44、t denitrification, nitrates would accumulate in water, which could lead to water degradation and disruption of the nitrogen cycle on earth.Anaerobic respiration capacity than aerobic respiration is less, but more than it makes in microbial fermentation, no oxygen condition can still through the elec

45、tron transport and oxidative phosphorylation to produce ATP, so it is very important to many microorganisms. A variety of substances other than deoxygenation can be used as final electron acceptors by various microorganisms, which fully reflects the diversity of microbial metabolic types.Heterotroph

46、ic and autotrophic organisms at the initial energy even though there is a huge difference, but the essence is their biological oxidation of the same, which include hydrogen transfer and hydrogen dehydrogenation, by three stages, after phosphorylation reaction and phase coupling, can produce general

47、energy required for life activities, ATP. But in specific types, autotrophic microorganisms have many types of biological oxidation and productivity, and their pathways are complex. There are few studies on the biological oxidation and productivity processes of some autotrophic bacteria. Whether che

48、molithotrophy type, or photolithotrophic type of microorganisms, the most important thing in their life activities in the first reaction is to CO2 reduction into simple organic CH2O levels, and then further synthesis of complex cell composition. This is a process of mass energy consumption and force

49、 H. In the inorganic nutrient microorganisms, the required energy ATP is produced by biological oxidation of reduced inorganic matter. The reduction force H is usually produced by the trans respiratory chain of ATP inorganic hydrogen;Chemoautotroph microbes with inorganic matter as an energy source,

50、 the general capacity of low efficiency, slow growth, but the view of ecology, energy and material they use is generally chemoheterotroph cannot use, so they and the production capacity of high efficiency and fast growth can not survive competition between heterotrophic microorganisms.The cell membr

51、ane of halophilic bacteria can be divided into two parts, red and purple, the former mainly containing cytochrome and flavin protein for respiratory chain vector of oxidative phosphorylation, the latter is very special, patchy in membrane (diameter of about 0.5(m) independent distribution, which acc

52、ounts for about half of the total cell membrane, which is unique to the purple membrane of photosynthesis.The content of accounting for 75% is a purple membrane called bacteriorhodopsin (bacteriorhodopsin) protein, and a protein - view of rhodopsin contains columnar cells in the retina (rhodpsin) is

53、 very similar,The two were treated with the purple yellow pigment aldehyde (retinal) as the prosthetic group.ATP synthesis of four physiological types of microorganisms under different light and oxygen conditionsSynthesis of microbial ATPAerobic anaerobicLight, darkness, light, darknessPhotosyntheti

54、c bacteria - - + -Green algae - - -Facultative anaerobic bacteria (E., coli) + + + +Salt Bacillus + + + -At present, bacteriorhodopsin is similar to chlorophyll, which is driven by photons and has proton pump action to produce proton trans membrane transport to form ATP. Halophilic bacteria can synt

55、hesize purple film only when the concentration of oxygen is very low and the light is in the environment. At this time, the normal oxidative phosphorylation could no longer meet the energy requirements and was instead provided by the phosphorylation of the photosynthetic membrane of the purple membr

56、ane.The proton gradient created by the purple membrane of solar energy conversion in addition to synthesis can drive ATP, but also for the establishment of halophilic bacteria sodium electrochemical gradient across the membrane in high salt environment, and thus completed a series of physiological a

57、nd biochemical functions.The discovery of photosynthetic phosphorylation of halophilic bacteria has added a new type of photosynthesis to the photosynthetic phosphorylation of classical chlorophyll and bacterial chlorophyll (green algae). Photosynthetic phosphorylation of the purple membrane is the

58、simplest photosynthetic phosphorylation reaction found so far, which is a good model for the study of chemical osmosis.Sixth chaptersThe training plate count method requires skilled and accurate operation, otherwise it is difficult to obtain the correct results:1) the sample is well mixed;2) each pipette and coating rod can only contact one dilution of the bacterial fluid