Definition of DNA recombinant Technology,

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DNA recombinant technology
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Definition of recombinant DNA technology(????)

• A series of procedures used to recombine DNA
  segments.. Under certain conditions, a
  recombinant DNA molecule can enter a cell and
  replicate.

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History of recombinant DNA technology

• Recombinant DNA technology is one of the recent
  advances in biotechnology, which was developed by
  two scientists named Boyer and Cohen in 1973.

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Basic principle of recombinant DNA technology

• The DNA is inserted into another DNA molecule
  called vector(??)
• . The recombinant vector is then introduced into
  a host cell where it replicates itself, the gene
  is then produced

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Basic principle of recombinant DNA technology
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Applications of Recombinant DNA Technology

• Large-scale production of human proteins by
  genetically engineered bacteria.
• Such as insulin, Growth hormone, Interferons
  and
• Blood clotting factors (VIII IX)

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Production of Human Insulin(???)

• 1) Obtaining the human insulin gene
• Human insulin gene can be obtained by making a
  complementary DNA (cDNA) copy of the messenger
  RNA (mRNA) for human insulin.

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• 2)Joining the human insulin gene into a
  plasmid(??) vector
• The bacterial plasmids and the cDNA are mixed
  together. The human insulin gene (cDNA) is
  inserted into the plasmid through complementary
  base pairing at sticky ends.

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3)Introducing the recombinant DNA plasmids into
bacteria
The bacteria E.coli is used as the host cell. If
E. coli and the recombinant plasmids are mixed
together in a test-tube.
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4)Selecting the bacteria which have taken up the
correct piece of DNA
The bacteria are spread onto nutrient agar. The
agar also contains substances such as an
antibiotic which allows growth of only the
transformed bacteria.
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Vaccinedevelopment (????)
The surface antigen of Plasmodium
falciparum, one of the 4 species of malaria has
been transferred to E. coli to produce amounts
large enough to develop a vaccine against this
form of malaria(??). It works well enough for
people who will visit a malarious region for a
relatively short period of time
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Hemophilia(???) A and B
The genes encoding factors 8 and 9 are on the X
chromosome. Like other X-linked disorders,
hemophilia A and B are found almost exclusively
in males because they inherit just a single X
chromosome, and if the gene for factor 8 (or 9)
on it is defective, they will suffer from the
disease. There are many different mutant
versions of the genes for factors 8 and 9.
Although some produce only a minor effect on the
function of their protein, others fail to produce
any functioning clotting factor.
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Treating Hemophilia A and B
Factor 8 and 9 can be extracted from donated
blood, usually pooled from several thousand
donors, and purified. Injections of this material
can halt episodes of bleeding in hemophiliacs and
have allowed countless young men to live
relatively normal lives. However, blood
contaminated with the human immunodeficiency
virus (HIV) was unknowingly used to manufacture
preparations of factors 8 and 9. Many have since
died of AIDS.
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The Future of Treating Hemophilia A and B

• all donated blood is now tested to see if the
  donor has been infected with HIV (as well as
  hepatitis B and C)
• plasma-derived preparations of factors 8 and 9
  are now treated with heat and/or solvents to
  destroy any viruses that might be present
• recombinant factor 8 and recombinant factor 9
  made by genetic engineering are now available.
• Now the treatment become more safety!

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Gene therapy for genetic diseases
Still in the experimental stages, it may be
possible to transfer the gene for normal adult
hemoglobin into marrow stem cells of an
individual with sickle-cell anemia(?????). The
goal is to promote the growth of enough cells to
produce enough normal hemoglobin to alleviate the
symptoms of sickle-cell anemia. One hundred
percent (100) is NOT required to attain the
alleviation of symptoms.
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Safety Issues in relation to Recombinant DNA
Technology
As bacteria is commonly used in recombinant DNA
work, there has always been a concern among
scientists and a worry among people that there is
a possibility that a clone of highly pathogenic
recombinant bacteria were made by accident, then
escaped from the laboratory and caused an
epidemic for which no drugs were available.
Recombinant DNA Advisory Committee (RAC) was
established in 1974 in the United States, which
responds to public concerns regarding the safety
of manipulation of genetic material through the
use of recombinant DNA techniques.

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2 types of control physical containment and
biological containment (??)
Effective biological safety programs were
operated in a variety of laboratories, which
include a set of standard practices generally
used in microbiological laboratories, and special
procedures, equipment and laboratory
installations that provide physical barriers of
varying degrees.
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Biological containment
In considering biological containment, the vector
(plasmid, organelle, or virus) for the
recombinant DNA and the host (bacterial, plant,
or animal cell) in which the vector is propagated
in the laboratory will be considered together.
(i) survival of the vector in its host outside
the laboratory, and (ii) transmission of the
vector from the propagation host to other
non-laboratory hosts.
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Dangerous of DNA recombinant technology

• It is always possible that an antibiotic-resistant
  plasmid could be accidentally incorporated into
  a dangerous pathogen with serious medical
  consequences.

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• http//www.ied.edu.hk/biotech/eng/classrm/explain/
  gene5.htm