Microbial growth

1
????? ????? ????????

• Microbial growth

????? ????????
2
Preserving Bacteria Cultures
??? ??? ????? ????????
- ??????? ?? (-50?) ??? (-95?). - ??????? (
????? ???????? ) ???? ( ?? -54? ??? -72? ?)
????? ?? ????? ????? ???? ??????? ???? ???? ????
????????? ???? .
3
Reproduction in Prokaryotes
- ?????? ???????? ??????? - ????? ????? / ???????
(??????? ) - ????? ??????? (??????? ????????) -
????? / ????? ????????
4
Binary Fission
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????? ?????? (????? ??????)
1- ????? ??? ?????? ? ?????? ???? ??????
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???? ??????
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2- ???? ??? ?? ???? ?????? ??????? ????????
?????????
3- ???? ?????? ?????? ????? ??? ????? ?????
????????
4- ????? ???????
???? ?????? ??????? (?????? ????? ????? ) ???? ??
????????
??? ?????? ???? ????? ?????? ??????
Figure 6.11
5
??? ?????
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??? ???????
Figure 6.12b
6

• If 100 cells growing for 5 hours produced
  1,720,320 cells

??? ????? ?????? ???? (100) ???? ????? ???? (5)
????? ????? ???? (320-172) ????
??? ??????? ???? ?????? ???? ??????? (?? ??????
) ???? ?????? ???? ??????? (?? ?????? )
??? ????? 60 ????? ??? ??????? 21 ????? /
????? ?????? ???????????????????
??? ???????

7
???? ?????? ???? ???????
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???????
Figure 6.13
8
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????? ( ??????? )
Figure 6.14
9
Phases of Growth
????? / ????? ?????
(4) ????? ?????

• 4 Phases
• 1. Lag Phase
• 2. Log Phase
• 3. Stationary Phase
• 4. Death Phase

1- ????? ????? ??????? 2- ????? ????? ????? 3-
????? ????? ??????? 4- ????? ??????
10
1. Lag Phase
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- ???? ???????? ???? ??? ???? ?? ???? . - ?????
???????? ??????? ??????? ??? .- ??????? ????
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?? ???? ????? ?? ??? ??????? - ?????? ???
??????? ??? ????? ??? ????? ??? ????? ??? ?????
???? ???? .
11
2. Log Phase
2- ????? ????? ?????
- ????? ???? ??? ?????? ???? ???? ( ????? ????? )
. - ?????? ??? ?????? ?? ?? ??? - ?? ??? ???????
???? ???????? ????? ?????? ??????? . - ????????
??????? - ????? ?????? ????????
12
3. Stationary Phase
3- ????? ????? ???????
- ???? ?????? ???? ????? - ???? ???????
??????? ????? ???? - ??? ?????? ???????? - ???
?????? - ??? ?????? - ????? ???????? ??????? -
???????? - ???? ??????? - ???? ???? ?? ?????
??? ??????? ????? ??????? ??????
13
4. Death Phase
4- ????? ??????
- ???? ?????? ???? ?? ???? ????? - ????? ??????
???? ????? - ??????? ???? ?? ???? ?????? ?????
????? ???????
14
Limiting Factors in the environment
- ??????? ?????? ??????? . - ??? ?????? ??????
??????? ??????? - ?????? - ????? ????????
??????? - ??? ????????. - ??????? ?? ????
??????? - ???? ??????? .
15
Enumeration of Bacteria
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- ????? ???????? ?????? 10 ????? ???? ?????? ??
????????? ?????? - ??????? ???????? / ????????
16
Direct Measurements of Microbial Growth
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• Plate Counts Perform serial dilutions of a sample

????? ???? ????? ????? ??????? ????? ?????
???? ??????? ???????
9 ?? ?? ????? ?? ?? ????
?????????
Figure 6.15, top portion
17
Plate Count
????? ??????? ??????

• Inoculate Petri plates from serial dilutions

????? ????? ???? ?? ????????? ????????
Figure 6.16
18
Plate Count

• After incubation, count colonies on plates that
  have 25-250 colonies (CFUs)

???? ??????? ???????
9 ?? ??? ??? ?????
- ??? ???????? ? ?? ?????? ?????????? ?? ???????
???? ??? 25-250 ???????
- ?????? ??? ?????????? ?? ????? ???????
???????? ?????? ??? ???????? ?? ???? ( ??? ????
?????? ? ??? ???? 32 ??????? ?? ??? ????? ?????
1/10.000 ?? ??????? ???????? ??? ????? ????
3210000 32000/?? ?? ??????)
Figure 6.15
19
Direct Measurements of Microbial Growth
???????? ???????? ????? ????????

• Filtration

???????
Figure 6.17a, b
20
Direct Measurements of Microbial Growth
???????? ???????? ????? ????????

• Multiple tube MPN test
• Count positive tubes and compare to statistical
  MPN table.

- ?????? ??????? ??????? - ???? ????????
????????? ??????? ?? ???? ??????
Figure 6.18b
21
Direct Measurements of Microbial Growth
???????? ???????? ????? ????????

• Direct Microscopic Count

??? ???????? ?? ????????? ?????? ??? ???????
???????
??????????
??? ??????? ???????
22
Direct Measurements of Microbial Growth
???????? ???????? ????? ????????
???? ????? ?? 25 ???? ????
???? ?????
?????
1- ???? ??? ?????? ???????? ????? ????? ????? ???
???????? ???????? ???????
3- ??????? ???????????? ?? ??????? ?? ????????
???????? ??????? ??? ???? ???? ??????? ??????
?????? ?????? ??? ?? 14 ???? ??????
Figure 6.19
23
Estimating Bacterial Numbers by Indirect Methods
????? ??????? ???????? ?????? ??? ????????
??????

• Turbidity

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???? ???
??? ?????
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????
???? ???? ?????
????? ??????? ???? ?? ??? ????? ?????
?????? ????????
Figure 620
24
Estimating Bacterial Numbers by Indirect methods
????? ??????? ???????? ?????? ??? ????????

• Metabolic activity
• Dry weight

- ?????? ?????? - ????? ?????