Download Ch. 12 Introduction to Biotechnology

Biotechnology
Engineering 2
Ch.12
Ms. Haut
Biotechnology:
Training & Careers
Career Spotlight: Bioengineer
DNA technology has many useful applications
– The Human Genome Project
– The production of vaccines, cancer drugs, and
pesticides
– Engineered
bacteria that
can clean up
toxic wastes
Copyright © 2003 Pearson Education, Inc. publishing Benjamin Cummings
•DNA and Crime Scene Investigations
– Many violent crimes go unsolved
•
For lack of enough evidence
– If biological fluids are left at a crime scene
•
DNA can be isolated from them
– DNA fingerprinting is a set of laboratory procedures
•
•
That determines with near certainty whether two
samples of DNA are from the same individual
That has provided a powerful tool for crime scene
investigators
Investigator at one
of the crime scenes
(above), Narborough,
England (left)
BACTERIAL PLASMIDS AND GENE
CLONING
•Plasmids are used to customize bacteria: An
overview
– Gene cloning is one application of DNA
technology
•
Methods for studying and manipulating genetic
material
The Bacterial Chromosome
• One double-stranded,
circular molecule of DNA
• Located in nucleoid
region, so
transcription and
translation can
occur simultaneously
• Many also contain
extrachromosomal DNA
in plasmids
Binary Fission
Plasmids
• Short, circular DNA
molecules outside the
chromosome
• Carry genes that are
beneficial but not
essential
• Replicate independently
of chromosome
en.wikipedia.org/?title=Plasmid
R Plasmids
• Contain genes that
confer antibiotic
resistance
• Medical consequences:
resistant strains of
pathogens due to
overuse of antibiotics
http://www.slic2.wsu.edu:82/hurlbert/micro101/images/AntibioticSelection.gif
Bacteria as Tools
• Bacterial Transformation—
– Uptake of DNA from the fluid surrounding the cell
– Causes genetic
recombination
Transformation
• Biotech companies use this technique to
artificially introduce foreign genes into
bacterial genomes (human insulin, human
growth hormone)
– Researchers can insert desired genes into
plasmids, creating recombinant DNA
•
Figure 12.1
And insert those plasmids into bacteria
(transformation)
E. coli
– If the recombinant
bacteria multiply
into a clone
• The foreign
genes are
also copied
1 Isolate DNA
Human cell
from two sources
2 Cut both
Plasmid
DNAs with
the same
restriction
enzyme
DNA
Gene V
Sticky ends
3 Mix the DNAs; they join
by base-pairing
4 Add DNA ligase
to bond the DNA covalently
Recombinant DNA
plasmid
Gene V
5 Put plasmid into bacterium
by transformation
6 Clone the bacterium
Bacterial clone carrying many
copies of the human gene
Restriction Enzymes
•Used to “cut and paste”
DNA
•The tools used to make
recombinant DNA are
– Restriction enzymes,
which cut DNA at
specific sequences
– DNA ligase, which
“pastes” DNA fragments
together
Genes can be cloned in recombinant
plasmids: A closer look
– Bacteria take the
recombinant
plasmids from their
surroundings
– And reproduce,
thereby cloning the
plasmids and the
genes they carry
Cloned genes can be stored in genomic
libraries
•Genomic libraries, sets of
DNA fragments containing
all of an organism’s genes
– Can be constructed and
stored in cloned bacterial
plasmids or phages
Genome cut up with
restriction enzyme
Recombinant
plasmid
Recombinant
phage DNA
or
Bacterial
clone
Plasmid library
Figure 12.4
Phage
clone
Phage library
Nucleic acid probes
Radioactive
probe (DNA)
•A short, single-stranded
molecule of radioactively
labeled or fluorescently
labeled DNA or RNA
ATCCGA
Mix with singlestranded DNA from
various bacterial
(or phage) clones
Single-stranded
G
DNA
TC
T
TA
A
T
C
GC
G
C
T
G
A
AT
T
T
C
C
G
A
– Can tag a desired gene
in a library
Master plate
A
A
T
G
G
C
G
C
TA
G
G
A
C
TA
Base pairing
indicates the
gene of interest
Master plate
Probe
DNA
Radioactive
single-stranded
DNA
Solution
containing
probe
Colonies
containing
gene of
interest
Gene of
interest
Single-stranded
DNA from cell
Filter
A
Film
Filter lifted
and flipped over
Hybridization
on filter
A special filter paper
is pressed against
the master plate,
transferring cells to
the bottom side of
the filter.
The filter is treated to break
open the cells and denature
their DNA; the resulting
single-stranded DNA
molecules are treated so that
they stick to the filter.
The filter is laid
under photographic
film, allowing any
radioactive areas to
expose the film
(autoradiography).
After the
developed film is
flipped over, the
reference marks
on the film and
master plate are
aligned to locate
colonies carrying
the gene of
interest.
CONNECTION
•Recombinant cells and
organisms can mass-produce
gene products
– Applications of gene cloning
include
•
The mass production
of gene products for
medical and other
uses
Table 12.6
Genetically modified organisms are
transforming agriculture
• New genetic varieties of animals and plants are being
produced
– A plant with a new trait can be created using the Ti
plasmid
• “Golden rice” has been genetically modified to
contain beta-carotene
– This rice could help prevent vitamin A
deficiency
Figure 12.18B
Drought resistant corn
Flavr Savr Tomato (CalGene)
•Transgenic organisms
– Are those that have had genes from
other organisms inserted into their
genomes
– Different organisms, including bacteria, yeast,
and mammals
•
Can be used for this purpose
These sheep carry a
gene for a human
blood protein that is a
potential treatment for
cystic fibrosis
Figure 12.6
CONNECTION
•DNA technology is changing the
pharmaceutical industry
– DNA technology
•
Is widely used to produce medicines and to
diagnose diseases
DNA technology is changing the
pharmaceutical industry and medicine
• Hormones, cancer-fighting drugs, and new
vaccines are being produced using DNA
technology
– This lab equipment
is used to produce
a vaccine against
hepatitis B
Figure 12.17
•Therapeutic hormones
– In 1982, humulin, human insulin produced by
bacteria
•
Became the first recombinant drug approved
by the Food and Drug Administration
Figure 12.7A
•Diagnosis and Treatment of Disease
– DNA technology
•
Is being used increasingly in disease diagnosis
•Vaccines
– DNA technology
•
Is also helping medical researchers develop
vaccines
Figure 12.7B