微生物学(绪论)88课件

1、食品微生物学FOOD MICROBIOLOGY霍 乃 蕊山西农业大学食品科学与工程学院 Food MicrobiologyLectured by Huo Nairui College of food science and engineeringIntroduction What is a microbe? A microbe or microorganism is a member of a large, extremely diverse, group of organisms that are lumped together on the basis of one property -

2、the fact that, normally, they are so small that they cannot be seen without the use of a microscope. The word is therefore used to describe viruses, bacteria, fungi, protozoa and some algae.The observation of microbe need to via the light microscope or EM个体形态需要借助光学显微镜或电子显微镜观察。 微生物(microorganism)：是存在

3、于自然界的一大群体形微小、结构简单、肉眼直接看不见，必须借助光学显微镜或电子显微镜放大数百倍、数千倍，甚至数万倍才能观察到的微小生物。exceptions1.the fruiting bodies of many fungi such as mushrooms are frequently visible to the naked eye; However, there are a few exceptions, 2. equally, some algae can grow to meters in length.Green algaedinoflagellateBrown algaedia

4、tomRed algaealgaeThe colony or lawn can be seem with the naked eye肉眼可观察到微生物聚集的群体菌落 或菌苔 微生物与人类的关系绝大多数微生物对人类和动、植物是有益的，而且有些是必需的。1.在自然界中元素的循环2.在工业方面的作用3.在农业方面的作用4.在医药方面的作用5.生物技术6.科学研究只有少数的微生物对人类和动、植物是有害的。The importance of microbiologyThe environmentMedicineFoodBiotechnologyresearchThe environment (1)1.M

5、icrobes are responsible for the cycling of carbon, nitrogen and phosphorus (geochemical cycles), all essential components of living organisms . 2.They are found in association with plants in symbiotic relationships.The environment (2)3.Maintain soil fertility and may also be used to clean up the env

6、ironment of toxic compounds (bio-remediation). 4.Some microbes are devastating plant pathogens which destroy important food crops, but others may act as biological control agents against these diseases.medicine The disease-causing ability of some microbes such as smallpox (Variola virus), cholera (V

7、ibrio cholera bacteria; ) and malaria (Plasmodium protozoa. ) is well known. However, microorganisms have also provided us with the means of their control in the form of antibiotics and other medically important drugs.Food Microbes have been used for thousands of years, in many processes, to produce

8、 food, from brewing and wine making, through cheese production and bread making, to the manufacture of soy sauce At the other end of the scale, microbes are responsible for food spoilage, and disease-causing microbes are frequently carried on food.research Microbes have been used extensively as mode

9、l organisms for the investigation of biochemical and genetical processes as they are much easier to work with than more complex animals and plants. Millions of copies of the same single cell can be produced in large numbers very quickly and at low cost to give plenty of homologous experimental mater

10、ial. An additional advantage is that most people have no ethical objections to experiments with these microorganisms.Eukaryotic microbes （真核细胞型微生物）细胞核分化程度高，有核膜和核仁，细胞器完整。如真菌。Prokaryotic microbes （原核细胞型微生物）细胞核的分化较低，仅有原始核，无核膜、核仁。细胞器很不完善。DNA和RNA同时存在。这类微生物众多，有细菌、放线菌、支原体、衣原体、立克次体、螺旋体。Non-cell type microbe

11、s（非细胞型微生物是最小的一类微生物。无典型的细胞结构，只能在活细胞内生长繁殖。核酸类型为DNA或RNA。病毒属之。3 types 8 kinds（三型八大类）Microbe typesAnimalia： some protozoaplantae： some microalgaeprotista： some protozoa、most alga and myxomycota fungi： yeast and mouldprocaryotae： bacteria，actinomycete,cyanobacteriaVira：virusesCell typeMicroorganismsNon -c

12、ell typeMicrobe types 病毒作为一界被提出的较晚，主要原因是：病毒和类病毒是生物还是非生物，是原始类型还是次生类型是长期争论未决的问题；病毒不是用双命法，分类不用阶元系统。但经过长期研究发现，病毒和细胞型生物具有共同特性：遗传物质是DNA(部分病毒是RNA)；使用共同的遗传密码。在此基础上，我国学者于1979年提出将无细胞结构病毒立为病毒界，从而建立了六界系统。 真菌的形态 杆菌 原核生物常见种类和常见形态（1） 球菌原和生物常见种类和常见形态（2）蓝细菌（螺旋藻）蓝细菌（鱼腥草）原和生物常见种类和常见形态（3） 古细菌（产甲烷细菌）细菌（耶尔森鼠疫杆菌）Slime mol

13、ds（粘菌类生物）孢子体粘菌类生物是原生生物中数量较少的一类，在其生长期或营养期为裸露的无细胞壁多核的原生质团，又叫变形体，在繁殖时期会形成多细胞的孢子囊构造并产生具有纤维质细胞壁的孢子。粘菌大多数生于森林中阴暗潮湿的地方，在腐木，落叶或其他湿润的有机物上生长。Slime molds（粘菌类生物）一个变形体Slime molds（粘菌类生物）Biological features of microorganisms微生物的生物学特性Powerful metabolic ability 代谢活力强Propagate rapidly 繁殖快Diverse species and widely di

14、stributed 种类多、分布广High adaptability and easily mutated 适应性强、易变异在人类可以生存的环境中，微生物无处不在 一般城市街道每立方米的空气中约含5000个 普通宿舍的空气中每立方米约含20000个 每克肥沃土壤中可含数亿个甚至更多的微生物 微生物在自然界中的分布极为广泛 Ubiquitous microbes在人类及其它高等生物难以生活的环境中有些微生物仍然可以正常生活 微生物的种类多 以真菌为例： 目前已经定名的真菌的有十几万种 每年世界上不断有许多新种被发现 据估计，自然界的真菌资源有150万种以上 Diverse species 微生物

15、的繁殖快、易培养 大肠杆菌（牛乳基质）繁殖一代12.5min，一昼夜能繁殖115代，数量可增殖到4.151034个，干菌体重量可达约1016吨 具强大的合成能力，可利用农产品废弃物、石油甚至CO2等为原料合成有机物。 微生物合成蛋白质的速度比植物快500倍，比动物快2000倍。 微生物繁殖速度快这一特性给动植物疫病的防治，食品的防腐、保鲜等带来了巨大的困难。 微生物的遗传特性易发生变化 个体结构简单，容易受到环境变化的影响而引起遗传性发生变异 细菌自发突变的频率为1O-8左右 各种物理、化学因子处理微生物可以促进微生物变异 容易通过基因工程获得变异性较大的菌种微生物学建立的社会背景 19世纪中

16、期，欧洲工业、农业规模化生产方式已经形成 当时工农业生产发展中出现的葡萄酒发酵酸败、人畜传染病等与微生物相关的问题急需解决 杰出科学家巴斯德、柯赫等科学家的贡献 The science of microbiology did not start until the invention of the microscope in the mid 16th century and it was not until the late 17th century that Robert Hooke and Antoine van Leeuwenhoek made their first records o

17、f fungi, bacteria and protoz-oa. The late 19th century was the time when the first real breakthroughs on the role of microbes in the environment and medi -cine were made. Louis Pasteur disproved the theory of sponta-neous generation, (that living organisms spontaneously arose from inorganic material

18、) and Robert Kochs development of pure culture techniques allowed him to show unequivocally that a bacterium was responsible for a particular disease. Since then the science has grown dramatically as microbiology impinges on all aspects of life and the environment.Formation and development of microb

19、iology 考古研究表明，我国在8000多年前的新石器时代早期就出现了利用微生物的“曲蘖酿酒” 我国商代酿酒技术已有很大的发展，已逐渐从农业中分化出来成为独立的手工业，出现了一些酿酒工场我国古代的各种酒器leeuwenhoek安东列文虎克（Antony ven Leeuwenhoek, 16321723）在1680年前后发现了自然界中存在的细菌、酵母菌、原生动物等微小生物。 1676年荷兰人列文虎克用自磨镜片，创造了一架能放大266倍的原始显微镜检查了污水、齿垢、粪便等，发现了许多肉眼看不见的微小生物，正确描述了微生物的形态有球形、杆状和螺旋样，为微生物的存在提供了科学依据。Bright f

20、ield microscopecondenserLight sourceMechanical stageeyepieceObjective lenstubebinocular microscope杰出科学家的贡献 法国化学家、微生物学家路易巴斯德（Louis Pasteur，18221895） Pasteur (Louis Pasteur,18221895)首先实验证明有机物发酵和腐败是由微生物引起，而酒类变质是因污染了杂菌所致。自此，微生物学成为一门独立学科。成功研制鸡霍乱、炭疽和狂犬病疫苗。德国科学家柯赫（Robert Koch，18431910） 揭示了传染病的本质 建立了微生物分离、接

21、种 、培养的方法 Robert Kochs original micrographs of anthrax bacillus （炭疽杆菌） (Robert Koch,18431910)创用固体培养基，使有可能将细菌从环境或病人排泄物等标本中分离成为纯培养，利于对各种细菌的特性分别研究。他还创用了染色方法和实验动物感染，为发现多种传染病的病原菌提供实验手段。郭霍法则：1.特殊的病原菌应在同一疾病中查见，在健康人中不存在；2.该病原菌能被分离培养得纯种；3.该纯培养物接种至易感动物，能产生同样病症；4.自人工感染的实验动物体内能重新分离得该病原菌纯培养。 For some diseases it

22、is very easy to identify the causative agent and establish how it causes disease. The symptoms of cholera, for example, can be clearly explained by the presence of the organism Vibrio cholera in the gut and the production of a toxin which causes the secretion of copious amounts of water from the gut

23、 (Topic F6). For other diseases, the cause and effect relationship may not be as clear. For example, Helicobacter pylori has only recently been accepted as the cause of many gastric ulcers as it was believed for a long time that bacteria could not survive in the stomach.Traditionally, the relationsh

24、ip between a bacterium and a disease has been established if the bacterium fulfills a number of criteria laid down by Robert Koch in the late 1800s:Kochs postulates The bacteria should be found in all cases and at all sites of the disease.在一切患病动物和所有患病部位都能发现该种病原菌2. The bacteria should be isolated fro

25、m the infected person and maintained in pure culture. 细菌应从受感染的患体中分离出来，并被培养为纯培养物 3. The pure cultured microbe should cause symptoms of the disease on inoculation into a susceptible individual.纯培养物接种到某个未经免役者的体内时，应出现病症。4. The bacteria should be reisolated from the intentionally infected host.细菌应从这种人为的受

26、感染者体内重新分离出来。Kochs postulates In practice, in many cases it has proved difficult to fulfill all of these criteria. Pure culture of bacteria in the laboratory has often been a problem. Although we are fairly certain that Mycobacterium leprae（麻风分支杆菌） is the cause of leprosy, it has yet to be cultured i

27、n laboratory medium, and has so far been cultured only in an animal model. In the case of an intestinal disease called Whipples disease（惠普尔病）, the bacterial agent responsible has only been discovered using modern polymerase chain reaction (PCR)-based DNA detection method. Criteria 3 and 4 of Kochs p

28、ostulates are also difficult to meet if no animal model for the disease is available or there is a lack of human volunteers. A modern-day modification of these postulates(法则) is now being used to establish if a particular virulence factor is necessary for the production of an infection. Potential vi

29、rulence factors（可能的致病力因子） are first identified, then removed by mutation or replaced by cloning and the microbe is then tested for virulence. In this way a clear understanding of the disease process of a number of microorganisms has been obtained.(Edward Jenner,17491823)首创用牛痘预防天花，为预防医学开辟了广阔途径。(Josep

30、h Lister,18271912)首创用石炭酸喷洒手术室和煮沸手术用具以防术后感染，为防腐、消毒，以及无菌操作奠定了基础。Watson and ClickThe development of microbiology need your participatingObscure （prehistory）period 朦胧阶段史前期（约8000年前1676）Morphological （primary）period 形态描述阶段初期（ 1 6761861）Physiological （foundation）period 生理水平研究阶段奠基期（ 18611897 ） Mordern times

31、 现代微生物学时期biochemical （develomental）period 生化水平研究阶段发展期（18971953）Molecular biological（maturation） 分子生物学水平研究阶段成熟期（1953至今）Formation and development of microbiology微生物学的形成和发展微生物学经验时期实验微生物学时期现代微生物学时期微生物学的发展过程三、近代微生物学的发展 微生物学研究工具的不断改进 社会和经济发展有大量的微生物学问题迫切需要解决 微生物学和其他生物科学共同发展，互相促进Food microbiologyDefenition

32、：Food microbiology is a science specializing in the relationship between food and microorganisms。 食品微生物学是专门研究微生物与食品之间相互关系的一门科学。Relationship with other subjects: As an important branch of microbiology，it is a comprehensive subject syncretized food related parts from general microbiology and industria

33、l，medical，agricultural microbiology . At the same time mixed the associated knowledge of biochemistry, mechanics and chemical engineering. 它是微生物学的一个重要分支，是一门综合性的学科，它融合了普通微生物学、工业微生物学、医学微生物学、农业微生物学与食品有关的部分，同时又渗透了生物化学、机械学和化学工程有关的内容.定义及与其他课程的关系Curriculum character： is the basic courses for the specialty

34、of food science and engineering. The aim of it is to lay the firm microbiological foundation for the students of food specialty and ensure them to skillfully master the related skills. 食品微生物学是食品科学与工程专业的专业基础课，学习这门课程的目的是为食品专业的学生打下牢固的微生物学基础和熟练的食品微生物学技能 Food microbiology课 程 性 质 Researches about food mic

35、robiology includes:Activity rules about food related microbesHow to utilize the beneficial microbes to manufacture food stuff for humanHow to control the harmful microbes to prevent the spoilage and deterioration of foodStudy the detective methods for food born microorganisms, set down the microorga

36、nism parameter in food, offer the guide for the judge of the food sanitation condition 研究内容包括：研究与食品有关的微生物的活动规律；研究如何利用有益微生物为人类制造食品研究如何控制有害微生物，防止食品发生腐败变质；研究检测食品中微生物的方法，制定食品中微生物指标，从而为判断食品的卫生质量而提供科学依据 Food microbioligy研 究 内 容 在食品生产、加工、储存、运输、销售等各个环节中涉及的微生物类型及形态特征 细菌 放线菌 酵母菌 霉菌 病毒 食品相关微生物的生物学特性 生理特性 遗传特性

37、生态学特点二、微生物引起的食品腐败变质现象及其机理 微生物引起各类食品的变质现象 微生物引起食品变质相关的内因、外因及其相互的联系 微生物引起食品腐败变质的机理。三、微生物相关的食品安全问题食品相关的细菌性食物中毒、食源性传染病、真菌毒素中毒症等 食源性疾病的微生物的特性，生长、产毒的条件，致病的机理及预防措施四、 防止食品腐败变质的方法防止食品腐败变质常用的方法 各类方法的适用范围、效果、影响因素 各类方法对食品品质的影响及可能的毒性五、食品微生物的检验技术研究检测食品微生物的技术 类群 数量 有毒代谢产物 研究监测食品品质变化的方法 根据食品中微生物的存在量、种群及其他相关特征的变化监测食

38、品的品质，进行早期的微生物危害预测、预防六、微生物在食品工业中的应用 微生物的对食品的转化作用 微生物合成的代谢产物 初生代谢产物 次生代谢产物 微生物酶制剂 微生物细胞 食品微生物学研究的内容包括与食品有关的微生物的特征、微生物与食品的相互关系及其生态条件等，所以从事食品科学的人员应该了解微生物与食品的关系。一般来说，微生物既可在食品制造中起有益作用，又可通过食品给人类带来危害。我国幅员辽阔，微生物资源丰富。开发微生物资源，并利用生物工程手段改造微生物菌种，使其更好地发挥有益作用，为人类提供更多更好的食品，是食品微生物学的重要任务之一。食品微生物学工作者应该设法控制或消除微生物对人类的这些有

39、害作用；采用现代的检测手段，对食品中的微生物进行检测，以保证食品安全性，这也是食品微生物学的任务之一。总之，食品微生物学的任务在于，为人类提供既有益于健康、营养丰富，而又保证生命安全的食品。Food microbiology Food microbiologyTask:1. Exploit and modify the microbiology resources ,make full use of its beneficial side in food making, therefore provide people with plentiful ,nutritional and functional health food.2. Try to minimize its harmful side ,th