specialization : Biotechnology
Intermediate report
Genetic engineering of plants for the
production of medicines
Start date :
Final date :
11-10-2010
15-11-2010
Group 5:
Iris Hensen
Emanuel Casagrande
Jan-Pieter Ploem
Thibaut Gabriel
Ilse Timmermans
Projectleader PHL : E. Wirix
Projectleader HELHa: A. Jaunard
Table of contents
Table of contents --------------------------------------------------------------------------------------------------------- 1
Introduction---------------------------------------------------------------------------------------------------------------- 3
General: Genetic engineering ------------------------------------------------------------------------------------------ 4
What’s genetic engineering? ---------------------------------------------------------------------------------------- 4
History------------------------------------------------------------------------------------------------------------------- 4
Techniques ------------------------------------------------------------------------------------------------------------- 4
Recombinant DNA-molecules ---------------------------------------------------------------------------------- 4
Genomic libraries -------------------------------------------------------------------------------------------------- 4
Eukaryotic cloning and expression systems ------------------------------------------------------------------ 4
Genetic engineering of plants ------------------------------------------------------------------------------------------ 5
Transformation -------------------------------------------------------------------------------------------------------- 5
Dicotyledonous plants--------------------------------------------------------------------------------------------- 5
Transformation by A. tumefaciens --------------------------------------------------------------------------- 5
Other methods --------------------------------------------------------------------------------------------------- 5
Monocotyledonous plants ---------------------------------------------------------------------------------------- 5
Biolistic transformation---------------------------------------------------------------------------------------- 5
Transformation by A. tumefaciens --------------------------------------------------------------------------- 5
Modifying plants ------------------------------------------------------------------------------------------------------ 5
Hepatitis B ----------------------------------------------------------------------------------------------------------------- 6
History------------------------------------------------------------------------------------------------------------------- 6
Contagion and pathogenesis ---------------------------------------------------------------------------------------- 6
Structure of Hepatitis B ---------------------------------------------------------------------------------------------- 6
Introduction
Has to be completed
General: Genetic engineering
What’s genetic
engineering?
Everyone knows Dolly the
sheep, the first cloned fullgrown animal in the world. For
a lot of people, it was the first
acquaintance with genetic
engineering. However, genetic
engineering is not a new
concept, it already exists for a
lot of years.
Genetic engineering refers to all
techniques that artificially move
or transfer genes from one
organism to another, to produce
new or modified organisms.
The target material is the
deoxyribonucleic acid (DNA)
molecule found in all living cells
of organisms, where genetic
information is stored.
Techniques
Recombinant DNAmolecules
When a DNA-molecule consists
of DNA coming from different
sources,
we
call
it
a
recombinant
DNA-molecule.
Genetic modification can be
applied in bacteria, plants and
in animals. We describe the
process in plants later in
chapter 2.
Restriction-endonucleases cut
the genomic DNA in little
(J.CraigVenter
Institute;Renaldo E. and ph
D. 1-7)
History
Genetic
Engineering
first
appeared in 1972, nineteen
years after the discovery of the
DNA structure. It was Paul
Berg, an American scientist,
who produced the first DNArecombinant
molecule.
Recombinant DNA is a type of
DNA that is artificially created
by inserting a strand or more of
DNA into a different set of DNA.
Later, in 1976 they bred the first
genetic modified mice. 10 years
after
the
mice,
scientist
approves release of the first
genetically engineered crop, a
gene-altered tobacco. These
days, genetic modification is
one of the most important
subjects in the biotechnology.
(E.Wirix;J.CraigVenter Institute)
fragments.
This
enzymes
recognize DNA-sequences from
4 to 8 nucleotides long. So, a
certain
DNA-molecule
will
always be cut by a certain
restriction-enzyme at the same
way.
After the cutting, we have some
restriction-fragments.
Each
fragment will be inserted in a
carrier molecule, which called a
vector. A vector can be: a
plasmid,
bacteriophages,
viruses
or
little
artificial
chromosomes.
The restriction-endonucleases
split the DNA in a certain way
that the fragments have a
single-stranded piece at the 3’
or 5’ end. These ends are
called the ‘sticky ends’. Sticky
ends can interact with sticky
ends from other DNA molecules
which are cut with the same
restriction-enzyme. This clutch
can be made permanently by
another enzyme, DNA-ligase.
Afterwards, the recombinant
DNA-molecule will be inserted
in a living host cell where they
replicate(cloning).
Genomic libraries
A DNA library consists of all
recombinant
DNA-molecules
which are obtained by all
restriction-fragments
from
ligating a specific DNA-sample
in vectors. These recombinant
DNA-molecules
will
be
introduced in cells where the
recombinants will replicate.
When a DNA-library contains all
the DNA from the genome from
one organism it calls a genomic
library. It’s also possible to
make a DNA-library outgoing
from all the mRNA-molecules
that are present in a certain
tissue. These are the cDNAlibraries.
Because
these
libraries has nothing to do with
our subject, we’re not going to
dwell on it.
Eukaryotic cloning
expression systems
and
These days, it’s possible to
develop recombinant DNAmolecules
which
will
be
inserted in the genome of
multicellular organisms. When a
zygote transform with the
strange DNA, it will develop in
an organism which contains the
recombinant DNA in some
cells. If we breed with these
organisms
we
can
get
transgenic organisms, which
contains the recombinant DNA
in all his cells.
(E.Wirix.)
Genetic engineering of plants
Genetic engineering is a
technique used to introduce
desired traits into a chosen
organism. To achieve this the
scientist has to insert a specific
gene which will encode for a
protein that is responsible for
the expression of a certain
defined trait. This insertion
followed by the expression of a
new
feature
is
called
‘Transformation’.
Transformation of plants is
possibly because they are
totipotent,
the
ability
to
regenerate from a single cell to
a full grown plant. This means
that if one cell is adjusted, all
the cells of the plant will have
the new gene. Some examples
of new traits are:
herbicide tolerance, drought
tolerance,
resistance
to
pathogens and insects. But it is
also possible to insert a gene
that is responsible for higher
nutrition values or for the
production of certain products
that can be of interest.
The gene used to introduce the
traits can be of any origin.
There is only one condition, the
trait has to be compatible with
the host organism.
To be certain that the plant is a
modified organism the desired
transgene will be accompanied
by
a
herbicide/antibiotic
resistance inducing gene. By
adding the herbicide or the
Modifying plants
Has to be completed
antibiotic, to which the modified
plant should be resistant, to the
nutrition medium the scientist
can check if the transformation
worked because only the plants
with the right gene will be able
to grow.
Transformation
To insert this transgene in the
DNA of the plant the scientist
can chose between a few
techniques,
one
more
favourable than the other.
There is a difference between
the insertion of a gene in
dicotyledonous
and
monocotyledonous plants.
Dicotyledonous plants
There are a few techniques
used to insert a gene in the
genome of the plant.
Transformation by A.
tumefaciens
Has to be completed
Other methods
Has to be completed
Monocotyledonous plants
These plants require a different
approach to insert a gene.
Biolistic transformation
“This technique of particle
bombardment, or biolistics, is
the most versatile and effective
way
of
creating
many
transgenic
plant
species,
including elite lines.”
When this technique is used an
isolated DNA-fragment has to
be coated on a metal particle.
Currently gold and tungsten are
often used metals because of
their inert nature.
The coated particles are shot
into the cell with a gene gun, a
biolistic device driven by a gas,
Helium for example.
When the particles pass
through the cell there is a
chance that the new gene will
be introduced in the genome of
the plant.
Transformation by A.
tumefaciens
This method is used less
frequently but when it can be
used it is the preferred
technique. The problem here is
that some important monocots,
such as: maize, rice and wheat
are resistant to A. tumefaciens
and cannot be transformed.
There have been some efforts
to alter the A. tumefaciens to
make it able to infect these
monocots. Until now the
greatest success has been with
rice.
(J.A.Thompson)
Hepatitis B
Hepatitis B is an infectious
illness caused by hepatitis B
virus which infects the liver of
primates, including humans,
and causes an inflammation
called
hepatitis.
Originally
known as "serum hepatitis", the
disease has caused epidemics
in parts of Asia and Africa, and
it is endemic in China.[2] About
a third of the world's population,
more than 2 billion people,
have been infected with the
hepatitis B virus. This includes
350 million chronic carriers of
the
virus.
There’s
no
relationship between Hepatitis
A and C with B.
History
In 1885, a number of cases of '
Serumhepatitis’ were located in
Bremen
(Germany)
after
administered
the
variola
vaccine (that contained human
lymph) to workers. Just in the
years forty and fifty of the
previous century a clear
distinction was made between '
serumhepatitis'
and
'
contagious Jaundice' on the
basis
of
transmission
experiments. In search of
genetic differences, scientists in
1965 found a particular protein
in blood of Aboriginals that they
called ' Australian-antigen'. This
proved to be later the hepatitis
B - surface antigen (HBsAg).
The
introduction
of
safe
effective vaccines (plasmaprepared
in
1983,
and
vaccinevaccine
DNA
VACCINEs in 1986,) have
increased the possibilities for
worldwide
suppression
of
hepatitis b virus (HBV) to
introduce vaccination programs
on child age.
Contagion and
pathogenesis
Hepatitis B is spread mainly by
exposure to infected blood or
body secretions. In infected
individuals, the virus can be
found in the blood, semen,
vaginal fluid, breast milk, and
saliva. Hepatitis B is not spread
through food, water, or by
casual contact. Hepatitis B also
may be spread from infected
mothers to their babies at birth
(so-called
'vertical'
transmission)
After entering, the Hepatitis B
virus is spread through the
blood through the body. By
adherence to specific sensors
the virus is incorporated in liver
cell but doesn’t damages these.
The immunological response of
the immunocompetent host to
presence of the Hepatitis B
virus, determines the clinical
picture. Cells which contain
virus antigens, humoral and
cellular processes of the
immune system are clearred.
As a result of a strong immune
response at the acute stage, an
acute hepatitis can show up. If
the immune response as
needed the virus is managed.
When the immune system
doesn’t response as needed, a
chronic infection can arise.
The incubation period lasts 4
weeks to 6 months (usually 2 to
3 months). The variation
depends on the amount of virus
in the inoculum, the route of
infection and host factors such
as host immunity.
Structure of Hepatitis
B
Photo 
http://www.uwcreative.com/por
tfolio.html ( We will add all
references soon )
The virus particle, (virion)
consists of an outer lipid
envelope and an icosahedral
nucleocapsid core composed of
protein.
The
nucleocapsid
encloses the viral DNA and a
DNA polymerase that has
reverse transcriptase activity.
The outer envelope contains
embedded proteins which are
involved in viral binding of, and
entry into, susceptible cells.
The virus is one of the smallest
enveloped animal viruses, with
a virion diameter of 42 nm, but
pleomorphic
forms
exist,
including
filamentous
and
spherical bodies lacking a core.
These
particles
are
not
infectious and are composed of
the lipid and protein that forms
part of the surface of the virion,
which is called the surface
antigen (HBsAg), and is
produced in excess during the
life cycle of the virus.
(LCI;Nettleman M., et al.)
Reference List
E.Wirix. "Biotechnologie." Van Gen tot Populatie, deel 1. 2010.
J.A.Thompson. "Genetic Engineering of Plants." Diss. 2009.
J.Craig Venter Institute. Genetics and Genomics Timeline.2004.
LCI. "Hepatitis B." Diss. 2008.
Nettleman M., et al. Hepatitis B.2010.
Renaldo E. and ph D. "Genetically Modified Organism: It's Implications to Food Safety and Consumers
Protection." Diss. 2000.
We also have to collect all written parts of the students from HELHa.