《微生物学》课程PPT课件讲稿（英文版）Lecture 6

Lecture 6 6. 8 Effect of environment on growth 6. 9 Microbial growth at cold Temperatures 6.10 Microbial Growth at High Temperatures 6. 11 Microbial Growth at Low or High pH 6.12 Osmotic Effects on microbial growth 6. 13 Oxygen and microbial Growth

Lecture 6 • 6.8 Effect of Environment on Growth • 6.9 Microbial Growth at Cold Temperatures • 6.10 Microbial Growth at High Temperatures • 6.11 Microbial Growth at Low or High pH • 6.12 Osmotic Effects on Microbial Growth • 6.13 Oxygen and Microbial Growth

Effect of Temperature on Growth Rate Enzymatic reactions occurring at maximal possible rate g Enzymatic reactions Optimum occurring at increasingly rapid rates Minimum Maximum Temperature Membrane gelling; Protein denaturation; transport processes collapse of the cytoplasmic so slow that growth membrane; thermal cannot occur lysis

Effect of Temperature on Growth Rate

Variations in Temperature Optima Thermophile Example Hyperthermophile hyperthermophile Bacillus stearothermophilus Example Example: Mesophile Thermococcus celer Pyrolobus fumarii Example Escherichia coli Psychrophile Polaromonas vacuolate 10 70 110 120 Temperature(C)

Variations in Temperature Optima

Psychrophiles Optimun15° C or lower · Maximun<20° Minimun<0° Many are very sensitive to moderate temperatures Enzyme denaturation at moderate temp Greater proportion of unsaturated fatty acids in membrane phospholipids Ocean depths: constant temp <5C

Psychrophiles • Optimum 15°C or lower • Maximum <20° • Minimum 0° • Many are very sensitive to moderate temperatures • Enzyme denaturation at moderate temp • Greater proportion of unsaturated fatty acids in membrane phospholipids • Ocean depths: constant temp <5oC

Psychrotolerant · Grow at0° Optimun20-40° Mesophiles capable of growth at low temperatures found in temperate climates

Psychrotolerant • Grow at 0° • Optimum 20-40° • Mesophiles capable of growth at low temperatures • found in temperate climates

Core sample of Mcmurdo Sound sea ice

Core sample of McMurdo Sound sea ice

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Table 6. 1 Upper temperature limits for growth Grou Upper temp limit Animals ISI 38 45-50 Crustaceans 49-50 Plants Vascular plants 45 Mosses 50 Eukaryotic Microorganisms Pr otozoa 56 Al gae 55-60 Fungi 60-62 Prokaryotes Bacteria Cyanobacteria 70-74 Anoxygenic 70-73 phototrophs Chemotrophs 95 Ar achaea 113

Table 6.1 Upper temperature limits for growth Group Upper temp limit (°C) Animals Fish 38 Insects 45-50 Crustaceans 49-50 Plants Vascular Plants 45 Mosses 50 Eukaryotic Microorganisms Protozoa 56 Algae 55-60 Fungi 60-62 Prokaryotes Bacteria Cyanobacteria 70-74 Anoxygenic phototrophs 70-73 Chemotrophs 95 Archaea 113

Figure 6.20 Yellowstone National Park

Figure 6.20 Yellowstone National Park

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