《微生物学》课程PPT课件讲稿（英文版）Lecture 5

Lecture 5 5.1 Microbial Nutrition 5.2 Culture Media 5.3 Laboratory Culture of Microorganisms 6.1 Cell Growth and binary Fission 6.2 Peptidoglycan Synthesis and Cell Division 6.3 Population Growth 6. 4 The growth cycle 6.5 Direct Measurements of microbial growth 6.6 Indirect Measurements of microbial Growth

Lecture 5 • 5.1 Microbial Nutrition • 5.2 Culture Media • 5.3 Laboratory Culture of Microorganisms • 6.1 Cell Growth and Binary Fission • 6.2 Peptidoglycan Synthesis and Cell Division • 6.3 Population Growth • 6.4 The Growth Cycle • 6.5 Direct Measurements of Microbial Growth • 6.6 Indirect Measurements of Microbial Growth

Overview of cell metabolism Nutrients for biosynthesis (fermentation products: acids, alcohols, cO2 and so on: reduced Anabolism (biosynthesis) nutrients, and Macromolecules and Catabolism Chemicals, ligh (energy source)

Overview of Cell Metabolism

Energy Classes of Microorganisms phototrophs: light as energy source chemotrophs: chemicals as energy source chemoorganotrophs: organic chemicals chemolithotrophs: inorganic chemicals

Energy Classes of Microorganisms • phototrophs: light as energy source • chemotrophs: chemicals as energy source – chemoorganotrophs: organic chemicals – chemolithotrophs: inorganic chemicals

Culture media Defined -made from purified chemicals Complex -exact chemical composition not known

Culture Media • Defined - made from purified chemicals • Complex - exact chemical composition not known

TABLE 4.4 Examples of culture media for microorganisms with simple and demanding nutritional requirements Defined culture medium for Defined culture medium for Complex culture medium for Escherichia coli Leuconostoc mesenteroides either E. coli or L. mesenteroides K2HPO4 7g K2HPO4 0.6 g Glucose 15 KH2PO: 2 g KH POA 0.6 Yeast extract 5 Peptone 5 g (NHD2SO: 1 g NHC 3 g MgSO4 0.1 g MgSO4 0. 1 g KH2PO428.1000m CaCl 0.02 g Glucose 25 g pH7 Glucose 4-10 g Sodium acetate 20 g Trace elements(Fe, Co, Mn, Zn Amino acids(alanine, arginine, Cu, Ni, Mo) 2-10 ug each asparagine, aspartate, cysteine, Distilled water 1000 ml glutamate, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline. serine, threonine, tryptophan, tyrosine, valine) 100-200 ug of each Purines and pyrimidines (adenine, L guanine, uracil, xanthine) 10 mg of each itamins(biotin folate, nicotinic acid pyridoxal, pyridoxamine, pyridoxine, boflavin, thiamine, pantothenate p-aminobenoic acid) 0.01-1 mg of ea Trace elements(see first column) 2-10 ug each Distilled water 1000 ml pHZ a The photos are tubes of (a)the defined medium described, and(b) the complex medium described. Note how the complex medium is colored from the vari- ous organic extracts and digests that it contains

a

quI Solid

Liquid Solid

Binary Fission DNA replication Some bacteria Cell can complete elongation one generation in as little as 20 Septum formation min Completion of septum with formation of distinct walls Cell separation

Some bacteria can complete one generation in as little as 20 min. Binary Fission

Ftsz ring Divisome Cytoplasmic proteins membrane Division plane

Ftsz ring Wall bands Growth zones