' '

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

• ??? ?????? ???? ??????? ????? ?????, ???? ??????
  ????? ??????? ???, ???, ??? ???? ?????? ???????
  ????????? ???????, ?????? ??????? ?????? ???
  ??????? ?????, ??? ?????? ??????.
• ????? ???????? ??????????'?? ??? ???????
  ???????? ???? ???? ???? ?????? ?? ?? ????????????
  ???????? ?? ???? ????? ?? ???? ??.

2
????? ??????? ????????? ?????????

• ??? ????? ???? ?????? ???? ??????? ??????????'??,
• ?????????? ?? ????? ?????? ???????? ????????? ,
  ?????? ??????? ???????? ?????
• ??????? ??????,
• ???? ????? ???????,
• ?????? ?? ???"?,

3
????? ??????? ????????? ?????????

• ????? ?????? ?? ???"? ???"?-????,
• ????? ?????? ????? ?? ???"? ???"?,
• ????? ??"? ?????? ?? ??? ???????.
• ??????? ????? ????? ?????? ????? ?????? ????????
  ?????,
• ??????? ??????? ???????? ?? ??????? ???????.

4
Some Historical Highlights Virology
5
The Hershey-Chase Experiment

• Finally, in 1952, Alfred Hershey and Martha Chase
  performed the definitive experiment that showed
  that DNA was, in fact, the genetic material.

6
The Hershey-Chase Experiment

• Hershey and his assistant Martha Chase

7
The Hershey-Chase Experiment

• Hershey and his assistant Martha Chase

8
The Hershey-chase Experiment - DNA Is the Genetic
Material

• Hershey came to CSH in 1950.
• Within two years Hershey and his assistant Martha
  Chase had performed and published the experiment
  that would secure him a Nobel Prize.
• This was the famous "blender experiment."

9
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10
????? ???? ??'???

• ???? ??'??? ???? ????? ?? E. Coli ???? ????' T2

11
????? ???? ??'???

• ????' ???? ?? ?? ?????? ????? ???? ????, ???? 20
  ???? ?????? ?????? ??? ???? ???'?? ?????.
• ????? ?????' ????? ?????? ???? ???? ????? ??????
  ?? ????'.
• ???? ????? ?? ????' ???? ????
• ??? ????' ???? ?????
• ?? ????? ????????
• ???? ?? ????? ?????? ????

12
The Hershey-chase Experiment - DNA Is the Genetic
Material

• By radiolabelling sulphur in one culture, they
  could tag the path of proteins and not DNA,
  because there is no sulphur in DNA and there is
  sulphur in the amino acids methionine and
  cysteine.

13
????? ???? ??'???

• ???? ??'??? ????? ????? ?? E.coli ???? ????? ??
  ???? MgSO4 ?? ??????? ?????? S35.

14
The Hershey-chase Experiment - DNA Is the Genetic
Material

• By radiolabelling phosphorous, the opposite
  effect could be achieved. DNA could be traced and
  not protein, because there is phosphorous in the
  phosphate backbone of DNA and none in any of the
  amino acids.
• Cultures could be grown in each of these two ways
  and the phage purified away from the host
  bacteria,

15
????? ???? ??'???

• ???? ??'??? ????? ????? ???? ?? E.coli ???? ?????
  ?? ???? K2PO4 ?? ???? ???? ??????????? P32.
• ??? ?? ?????? ?? ???????? ????'?? T2.
• ?? ????'?? ?????? ????? ????? ?? ???????? P32
  ???"? ????.

16
????? ???? ??'???

• ???? ??'??? ????? ????? ?? E.coli ???? ????? ??
  ...

17
The Hershey-chase Experiment - DNA Is the Genetic
Material

• resulting in one culture in which only the phage
  protein was labelled,
• and one culture in which only the phage DNA was
  labelled.

18
????? ???? ??'???

• ??? ????????? ??????? ????? ?????? ?????? ??????
  E. coli ?????? ???? ??? ?????????.
• ????? ??? ???? - ???? ???? ??????? ?????
  ???????? ????? ?????? ??????? ????? ?????? ??
  ??????? ??? ?????.

19
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20
Some Historical Highlights Virology

• There seems to be agreement that the history of
  virology dates from the end of the 19th century
  and is attributed to the observations of Adolf
  Mayer in Germany, Dimitri Ivanofsky in Russia and
  Martinus Beijerinck in the Netherlands, all of
  whom were led to their discoveries during their
  investigations of diseased tobacco plants.

21
Some Historical Highlights Virology

• Each had evidence that bacteria analogous to
  those that had been previously described could
  not cause the disease.
• Beijerinck discovered that the agent causing the
  disease could reproduce itself and he described
  it as a "contagium vivum fluidum" or contagious
  living liquid.

22
??"? ???? ??????? ??????????? ???????? ?? ????
(TMV)
23
????????- TMV

• ???? ?? ??????? ???????? ???? ???????, ??????
  ????? TMV
• ???? 1892 ????? ?????? ???? ???????? ?? ????.
• ??????? ????????? ??? ???? ?? ???? ??? ??????
  ??????? ??? ?? ???? ????? ????? ?????? ????? ????
  ??? ???? ?????.
• ????????? ???? ?? ????? ?????? ?? ??? ???? ??
  ???? ??? ?????? ????? ?? ?? ????? ?????? ??????
  ?????????? ?????.
• ????????? ???? ?? ???? ???????? ?? ???? ????? ??
  ??? ????? ???????? ????????, ??, ???????, ?? ???
  ??????? ?????.

24
???????? - TMV

• ???? 1898 ??? ??????? ??????? ?? ???? ???????? ??
  ????, ????? ?? ???, ?? ???? ???? ????, ????
  ?????, ????? ????? ??????.
• ?????? ???, ?? ???, ?? ????? ?????? ??? ???????
  ????? ???? ???? ?????? ???? ?? ????? ?????, ??
  ??? ?????.
• ??????? ??? ?? ????? ?"???" ?? ????? ??????
  ?????? ?????? ??? ?????? ?? ????? ??????. ???
  ???? ?????? ????? ???? ?????? ??? ?????? ???? ??
  ???? ?????????? (?????).

25
???????? - TMV

• ???? 1935 ????? ????? ???? ?? ???? ???????? ??
  ????.
• (TMV). ??? ???? ????? ?? ??????? ?????? ??????
  ??????? ?????? ???? ?????? ?? ?????? ???????,
  ????? ????? ???? ?? ???? ????? ?? ???? ????.

26
???????? - TMV

• ???? 1937 ???? ???? ????? ?? ????? ????? ??????
  ?????? ?- TMV, ????? ???? ????? ?? ????? ??????
  ????? (??????????????).
• ????? ???????, ?? ????? ????????? ?????????, ????
  ???? ??????? ????? ????.

27
???????? - TMV

• ????????? ?????-????? ??? ???? ???? ?? ?????
  ????? ?? ???? ???????? ?? ????, ??????, ??????
  ?????? ??? ?????? ?? ??????? ?????????.
• ???? 1954 ?????-????? ????? ???? ????? ????? ????
  ??? ????? ????? ?? ??????? ?????????- ?????? ??
  ????? ???????
• ???? ??????
• ?????-????? ??? ??? ???? ????? ?? TMV (? ?- ?),
  ??? ??? ??? ???? ?????? ????? ???? ?????????? ??
  ??.
• ??? ?? ???? ??? ???????, ????? ???? ???? ????.

28
??????? - TMV

• ???? ?? ???? ?? ?? ? ?? ?????? ?? ?? ?, ???
  ???? ?? ?? ? ?? ?????? ?? ?? ?.
• ?????-????? ????? ???? ??? ??????? ?????????
  ????, ???? ???? ??????? ?????? ??????????.
• ??????
• ???? ????? ?????? ???? ??????? ??? ????
• ??? ? ????? ? ??? ? ????? ? ??????? ??? ?
• ??? ? ????? ? ??? ? ????? ? ??????? ??? ?

29


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31
???????? - TMV

• ?????? ?? ?????-????? ????? ?????? ????? ????????
  ???? ?? ??????? ?????? ??????? ???? ????????????
  ????.
• ?????-????? ????? ?? ???? ????? ?? ???????
  ????????? ??? ????? ?????? ??? ??????? ????????.
• ????? ???? ???? ?? ??? ?????? ????? ???? 1953
  ???? ?? ??????? ????????? ????????? ????
  ???????????? ????????? ????.

32
Bacteriophages

• 1966.....Norton D. Zinder.
• For his discovery of RNA bacteriophages, a new
  class of bacteria-attacking viruses, which have
  provided researchers with a highly valuable and
  convenient method of studying fundamental
  processes in all living cells.

33
Bacteriophages

• 1969.....William B. Wood, IIIFor his genetic
  dissection of the mechanism of assembly of the
  bacterial virus particle and reconstruction of
  the virus in vitro.

34
Bacteriophages

• 1970.....A. Dale KaiserFor his discovery that
  pure phage lambda DNA can infect susceptible
  bacterial cells and produce progeny, and for the
  effect of this discovery on the whole field of
  bacterial virus genetics.

35
Retroviruses

• 1974.....David BaltimoreFor his distinguished
  leadership in virus research, and for his
  discoveries on the reproduction and enzymology of
  RNA viruses that has greatly advanced the science
  of molecular biology.

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37
Transduction

• Generalized transduction (depicted below).  A
  piece of host DNA gets packaged by mistake,
  instead of the phage DNA.  This rare event
  results in a phage delivering only bacterial DNA
  to the next host.  The DNA then recombines
  homologously, replacing the host allele.

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40
Transduction

• Specialized transduction, in which a lysogenic
  prophage recombines itself out of the genome (by
  site-specific recombination) and mistakenly
  includes a piece of bacterial DNA.  The resulting
  phage progeny can infect cells to produce
  lysogens with a second copy of the allele they
  had packaged, attached to the phage DNA.

41
Transduction

• Generalized transduction - all regions of
  chromosome transduced, only chromosomal DNA
  (i.e., no phage DNA) in transducing particles.
• Specialized transduction - only specific regions
  of chromosome located near attachment site are
  transduced, transducing particles carry both
  chromosomal DNA and phage DNA.

42
??????? ?????? ??????

• ????? ???? ????? ?? ?????? ???????? ???? ????
  ????? ???????
• 1. ??? ??????? ?? ???? ??????? ??? ??????- ???
  ??????? ??? ????? ??????? ???? ??? ?????? ??????.

43
??????? ?????? ??????

• 2. ????? ????- ????? ?? ??? ?? ???? ???? ?????
  (??????, ????? ??????- ????? ?? ?????? ??????????
  ??????).
• ?????? ???? ?????? ???? ?????? ??????? ??????
  ???? ???? ???? ?????? ???????? ?? ?????? ?? ????
  ????.

44
????? ??? ?????

• ?? ??? ?????? ?????? "???????" ???? ????? ??????
  ???????.
• ????? ????? ???? ????? ?????????? ???? ?????????.
• ????????? ?????- ????? ???????? ??????? ??? ?????
  ???? ??? (72-48 ???? ???? ??????????). ??????????
  ????? ??????? ???"? ??????? ???????? ????? ????
  ??? ??????.

45
????? ??? ?????

• ????????? ?????- ??? ????? ???? ?? ????? ???????
  ???? ???? ?? ????? ??? ?????? ???? ???????.
  ???????? ?? ?????? ???????? ????? ?????? ?????
  ???. ??? ??, ??????? ????? ????????????.

46
Genetic  Engineering

• Tiki's Quick Guide
• Genetic engineering is about scientists altering
  the 'recipes' for making life - the genes which
  you find in all living things.
• Doing this is very clever and could be very
  useful.
• But it's all happening much too fast and nobody
  knows what the effects of making and eating such
  living things will be.

47
Genetic  Engineering

• Many kinds of life could be damaged.
• And suppose people eat 'genetic' food for many
  years?
• Will they be harmed by it?
• Nobody knows for sure. So why the rush?

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