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Bacterial Physiology

Bacterial Physiology. Bacterial chemical components. Water : free water and compound water. Inorganic salt : phosphus, potassium magnesium, calcium, nitrium,etc. Protein : 50%-80% of dry weight according bacterial kinds and age. Sugar : mainly distributing in cell wall and capsule.

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Bacterial Physiology

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  1. Bacterial Physiology

  2. Bacterial chemical components • Water: free water and compound water. • Inorganic salt: phosphus, potassium magnesium, calcium, nitrium,etc. • Protein: 50%-80% of dry weight according bacterial kinds and age. • Sugar: mainly distributing in cell wall and capsule. • Lipids: composed of lipid, fatty acid, wax, etc. • Nucleic acid: RNA and DNA.

  3. Environmental factors affecting growth of bacteria • 1. Nutrients • 2. Temperature • 3. hydrogen ion concentration ( pH ) • 4. Oxygen Requirements:氧气、二氧化碳 • 5. Osmotic pressure 渗透压

  4. Bacterial Nutrition and Growth • Classification based on their source of carbon • 根据细菌所利用的能源和碳源的不同，将细菌分为两大营养类型。 • 1. Autotrophs 自养菌 • 2. Heterotrophs 异养菌 :saprophytes 腐生菌 ; parasites 寄生菌

  5. Nutrient requirements of bacterial growth: • 1. Water • 2. Carbon source • 3. Nitrogen source氮源 • 4. Minerals 无机盐 • 5. Growth factors生长因子：that a cell must have for growth but cannot synthesize itself. Such as amino acids, purines嘌呤, pyrimidines嘧啶, and vitamins 流感嗜血杆菌 X因子（高铁血红素） V因子（辅酶Ⅰ或Ⅱ）

  6. Temperature • Psychrophilic forms 嗜冷菌(15-20℃) • Mesophilic forms 嗜温菌（30-37℃）include all human pathogens and opportunists. • Thermophilic forms 嗜热菌（50-60℃）

  7. pH • Neutrophiles 嗜中性菌（ 5 to 8） • Acidophiles 嗜酸性菌（below 5.5） • Alkaliphiles 嗜碱性菌（above 8.5）

  8. Gas Requirements

  9. 2O2- +2H+ SOD H2O2+O2 2H2O2 触酶 2H2O +O2 H2O2+AH2过氧化物酶 2H2O+A Obligate anaerobes 专性厌氧菌 • 缺乏分解有毒氧基团的酶：catalase 触酶, peroxidase 过氧化物酶, superoxide dismutase 超氧化物歧化酶 • 缺乏氧化还原电势高的呼吸酶：细胞色素、细胞色素氧化酶 • 破伤风梭菌、肉毒梭菌

  10. CO2 • N. meningitidis • N. gonorrhoeae

  11. Bacterial Growth • Bacteria multiply by binary fission 二分裂

  12. Generation time 代时：the time it takes for a population of bacteria to double in number • many common bacteria ：20~60 min • most common pathogens in the body： 5-10 hours

  13. Population dynamics群体动力学--the growth curve生长曲线 • a. The Lag Phase 迟缓期(A) • b. The Exponential Phase 指数期(C) • c. The Maximum Stationary Phase 稳定期(E) • d. The Death or decline Phase 衰亡期(F)

  14. growth curve 总菌数 9.0 稳定期 细菌数的对数次 8.5 8.0 衰退期 7.5 活菌数 7.0 对数期 6.5 6.0 迟缓期 5.5 0 30 5 10 15 25 20 小时

  15. Microbial Metabolism细菌的新陈代谢 • Energy Metabolism • Medical Important Metabolic Products • anabolic processes合成代谢 • catabolic processes 分解代谢

  16. Energy Metabolism • 1.Cellular respiration is the process cells use to convert the energy in the chemical bonds of nutrients to ATP energy. 细胞呼吸是细胞将营养物质化学键中的能量转化为ATP的过程。 • Aerobic respiration 需氧呼吸 • Anaerobic respiration 无氧呼吸 • 2. Fermentation 发酵

  17. Metabolic Products and Biochemical Testing 代谢产物和生化试验 • a. Carbohydrate Fermentation Tests 糖发酵试验

  18. b. Methyl Red (MR) Test 甲基红试验 • 葡萄糖→丙酮酸→乙酰甲基甲醇 甲基红 - • 葡萄糖→丙酮酸 甲基红 + 大肠杆菌＋ 产气杆菌－

  19. c. Voges-Proskauer (VP) Test 葡萄糖→丙酮酸→乙酰甲基甲醇 →二乙酰→红色化合物 + 胍基化合物 葡萄糖→丙酮酸 － 大肠杆菌－ 产气杆菌＋

  20. d.Citrate Utilization Test 枸橼酸盐利用试验 利用枸橼酸盐生长 + 不能利用 - 大肠杆菌－ 产气杆菌＋

  21. e. Indole Test 吲哚试验 • 色氨酸→吲哚→玫瑰吲哚 吲哚试剂 大肠杆菌＋ 产气杆菌－

  22. Indol test VP test Methyl test Citrate utilization test I M Vi C试验 常用于肠道杆菌的鉴定

  23. f. HydrogenSulfide (H2S) Production硫化氢试验 • g. Urease Test 尿素酶试验

  24. Synthetic Products a. Pyrogen 热原质（致热原） • This is a fever-producing substance synthesized by bacteria. 细菌合成的一种注入人体或动物体内能引起发热反应的物质。 LPS/耐高温/去除方法：250℃干烤、蒸馏、吸附剂等/制备和使用注射药品过程无菌操作 b. Toxins and Invasive Enzyme毒素与侵袭性酶 • Exotoxin • Invasive Enzyme （侵袭性酶 ）

  25. c. Pigments色素 • 水溶性（绿脓杆菌） • 脂溶性（金黄色葡萄球菌） • d. Antibiotics 抗生素 • e. Bactericin 细菌素 • f. Vitamins 维生素

  26. Artificial Cultivation of Bacteria细菌的人工培养 • Medium培养基：由人工方法配制而成的，专供微生物生长繁殖使用的混合营养物制品

  27. Classification according to basic ingredients • a. Minimal essential growth medium基础培养基 • b. Enrichment medium增菌培养基 • c. Selective medium选择培养基 • d. Differential medium 鉴别培养基

  28. Classification according to physical condition: • a．liquid medium • b．solid medium • C．semisolid medium

  29. Phenomena of bacterial growth • In liquid medium 表面生长 混浊生长 沉淀生长

  30. On plate

  31. Semisolid medium 无动力 有动力

  32. Purposes of bacterial artificial cultivation • 感染性疾病的诊断，鉴别和药敏试验 • 生物制品的制备 • 细菌学研究

  33. designated by a Latin binominal（拉丁双名法） • 前属名，后种名 • Staphylococcus (genus) aureus (species)

  34. Bacterial Classification 界、门、纲、目、科、属、种

  35. Some of the features that have been used to classify bacteria • Gram stain (cell wall structure) Mole percent G+C in the genome Growth temperature Ability to form heat stable spores Electron acceptors for respiration (if any) Photosynthetic ability Motility Cell shape Ability to use various carbon and nitrogen sources Special nutritional requirements (e.g., vitamins)

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