麻省理工大学课件：系统微生物学4-微生物生长(PPT)
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• g = t/n
Graph of cell growth over time removed due to copyright restrictions. See Figure 6-6b in Madigan, Michael, and John Martinko. Brock Biology of Microorganisms. 11th ed. Upper Saddle River, NJ: PearsonPrentice Hall, 2006. ISBN: 0131443291.
Fts proteins and the “divisome”
Image removed due to copyright restrictions. See Figure 6-2b in Madigan, Michael, and John Martinko. Brock Biology of Microorganisms. 11th ed. Upper Saddle River, NJ: Pearson Prentice Hall, 2006. ISBN: 0131443291.
Exponential growth
• From semi-log plot of cell density s a function of time can determine generation time (g) from time (t) and number of generations (n)
Images removed due to copyright restriction See Figure 6-3 in Madigan, Michael, and John Martinko. Brock Biology of Microorganisms. 11th ed. Upper Saddle River, NJ: Pearson Prentice Hall, 2006. ISBN: 0131443291.
log N = n log2 + log N0
n = log N - log N0 0.301
Related growth parameters
• Slope = 0.301 n/t = the specific growth rate (k)
• Division rate (v) = 1/g • Slope = v/3.3
Peptidoglycan synthesis
• New cell wall is synthesized from the FtsZ ring
• Need to extend existing chains without compromising integrity
• Autolysins without aFra Baidu bibliotektolysis
Graph showing the lag, exponential, stationary, and death phases of cell growth removed due to copyright restrictions. See Figure 6-8 in Madigan, Michael, and John Martinko. Brock Biology of Microorganisms. 11th ed. Upper Saddle River, NJ: Pearson Prentice Hall, 2006. ISBN: 0131443291.
Peptidoglycan
G MG MG MG MG MG MG
G M G M GM G Cytopasmic membrane Outside
M G MG MG
Growing point of cell wall
PP
Inside Pentapeptide
MG PP
Bactoprenol
Figure by MIT OCW.
Growth parameters
• Number of cells (N) after n generations beginning with N0 cells
• N = 2n N0
Graph of cell growth over time removed due to copyright restrictions. See Figure 6-7b in Madigan, Michael, and John Martinko. Brock Biology of Microorganisms.11th ed. Upper Saddle River, NJ: Pearson Prentice Hall, 2006. ISBN: 0131443291.
• If you know n and t, you can calculate g, k, and v for organisms growing under different conditions
The growth cycle
• Lag phase • Exponential phase • Stationary phase
Diagram showing the process of binary fission removed due to copyright restrictions. See Figure 6-1 in Madigan, Michael, and John Martinko. Brock Biology of Microorganisms. 11th ed. Upper Saddle River, NJ: Pearson Prentice Hall, 2006. ISBN: 0131443291
Binary fission
• In prokaryotes, growth = increase in number of cells
• Generation time is the time required for 1 bacterium to become 2 bacteria
• E. coli generation time is ~ 20 min
Graph of cell growth over time removed due to copyright restrictions. See Figure 6-6b in Madigan, Michael, and John Martinko. Brock Biology of Microorganisms. 11th ed. Upper Saddle River, NJ: PearsonPrentice Hall, 2006. ISBN: 0131443291.
Fts proteins and the “divisome”
Image removed due to copyright restrictions. See Figure 6-2b in Madigan, Michael, and John Martinko. Brock Biology of Microorganisms. 11th ed. Upper Saddle River, NJ: Pearson Prentice Hall, 2006. ISBN: 0131443291.
Exponential growth
• From semi-log plot of cell density s a function of time can determine generation time (g) from time (t) and number of generations (n)
Images removed due to copyright restriction See Figure 6-3 in Madigan, Michael, and John Martinko. Brock Biology of Microorganisms. 11th ed. Upper Saddle River, NJ: Pearson Prentice Hall, 2006. ISBN: 0131443291.
log N = n log2 + log N0
n = log N - log N0 0.301
Related growth parameters
• Slope = 0.301 n/t = the specific growth rate (k)
• Division rate (v) = 1/g • Slope = v/3.3
Peptidoglycan synthesis
• New cell wall is synthesized from the FtsZ ring
• Need to extend existing chains without compromising integrity
• Autolysins without aFra Baidu bibliotektolysis
Graph showing the lag, exponential, stationary, and death phases of cell growth removed due to copyright restrictions. See Figure 6-8 in Madigan, Michael, and John Martinko. Brock Biology of Microorganisms. 11th ed. Upper Saddle River, NJ: Pearson Prentice Hall, 2006. ISBN: 0131443291.
Peptidoglycan
G MG MG MG MG MG MG
G M G M GM G Cytopasmic membrane Outside
M G MG MG
Growing point of cell wall
PP
Inside Pentapeptide
MG PP
Bactoprenol
Figure by MIT OCW.
Growth parameters
• Number of cells (N) after n generations beginning with N0 cells
• N = 2n N0
Graph of cell growth over time removed due to copyright restrictions. See Figure 6-7b in Madigan, Michael, and John Martinko. Brock Biology of Microorganisms.11th ed. Upper Saddle River, NJ: Pearson Prentice Hall, 2006. ISBN: 0131443291.
• If you know n and t, you can calculate g, k, and v for organisms growing under different conditions
The growth cycle
• Lag phase • Exponential phase • Stationary phase
Diagram showing the process of binary fission removed due to copyright restrictions. See Figure 6-1 in Madigan, Michael, and John Martinko. Brock Biology of Microorganisms. 11th ed. Upper Saddle River, NJ: Pearson Prentice Hall, 2006. ISBN: 0131443291
Binary fission
• In prokaryotes, growth = increase in number of cells
• Generation time is the time required for 1 bacterium to become 2 bacteria
• E. coli generation time is ~ 20 min