上海交通大学：《医学微生物》课程教学资源（PPT课件讲稿）英文版 chaper 3 Bacterial Physiology

Bacterial Physiology

Bacterial Physiology

Bacterial chemical components o Water: free water and compound water o Inorganic salt: phosphus, potassium magnesium calcium. nitrium etc Protein 50%0-80% of dry weight according bacterial kinds and age o Sugar: mainly distributing in cell wall and capsule Lipids: composed of lipid, fatty acid, wax, etc Nucleic acid: rna and dNA

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

Approximate Composition of a Microbial Cell ( Dry Weight) Sodium 1% Calcium 0.5%, Magnesium 0.5%, Chlorine 0. 5% Potassium 1% Iron 0.2% All others.3%6 Sulfur 1 1% Phosphorus 3% Hydrogen 8% Nitrogen 14% Carbon 50% xygen 20%

Major elements, their sources and functions in bacterial cells bo of dry ment Function Carbon organic compounds Main constituent of cellular material H2O organIc Constituent of cell material and cell water: O2 Oxvgen compounds, CO2 and is electron acceptor in aerobic respiration Nitrogen NH3. NO3. organic Constituent of amino acids, nucleic acids compounds, N2 nucleotides and coenzymes H2O. organic Main constituent of organic compounds and Hvdrogen compounds, H2 cell water phosphates Constituent of nucleic acids, nucleotides, Phosphorus 3 (PO4) phospholipids, LPs, teichoic acids SO4. H2S. So, organic Constituent cvsteine. methionine Sulfur sulfur compounds glutathione. several coenzymes Potassium 1 Potassium salts Main cellular inorganic cation and cofactor for certain enzvmes Inorganic cellular cation. cofactor for certain Magnesium 0.5 Magnesium salts enzvmatic reactions Calcium Inorganic cellular cation, cofactor for certain Calcium salts enzymes and a component of endospores Component of cytochromes and certain Ir 0.2 Iron salts nonheme iron-proteins and a cofactor for some enzvmatic reactions

Environmental factors affecting growth of bacteria ●1. Nutrients ●2. Temperature 3. hydrogen ion concentration(ph) Oxygen Requirements:氧气、二氧化碳 ●5.0 smotic pressure渗透压

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

Bacterial Nutrition and growth o 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

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

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)

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）

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℃)

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℃）

Temperature requirements for growth Temperature for growth(C) Irou Minimun Optimum Maximum Comments ochre phile Below 0 10-15 Below 20 Grow best at relatively low T able to grow at low t but prefer Psychrotrophs 0 15-30 Above 25 derate T Mesophile 10-15 30-40 Below 45 Most bacteria esp. those living in association with warm-blooded animals Thermophile 45 50-85 Above 100 Among all thermophiles is wi (boiling) variation in optimum and maximum T

Minimum, maximum and optimum temperature for growth of bacteria. Temperature for growth(C) Bacterium Minimum Optimum Maximum Listeria monocvtogenes 30-37 Vibrio marinus 15 Pseudomonas maltophilia 35 Thiobacillus novellus 25-30 Staphylococcus aureus 10 30-37 Escherichia coli 10 Clostridium kluver 19 Streptococcus pyogenes 0 Streptococcus pneumoniae 42 Bacillus flavothermus 30 Thermus aquaticus 70-72 79 Methanococcus jannaschii 90 Sulfolobus acidocaldarius 70 75-85 Pvrobacterium brockie 8O 102-105 115