Transcript Cell Technology

CELL TECHNOLOGY
Stem Cells
Definition
Unspecialized cells that have two defining
properties:
1) the ability to differentiate into other cells
2) the ability to self-regenerate to form more
stem cells
Importance
Development
Repair of Adult Tissue
Cancer
CELL TECHNOLOGY
Stem Cells
Differentiation Potential
Totipotent Cells
Can develop into all cell types
Pluripotent Cells
Can develop into cells of the three germ
layers (ectoderm, mesoderm, endoderm)
Multipotent Cells
Can develop into cells of a few types
Types
Zygote:
Totipotent
Embryonic: Pluripotent
Adult:
Multipotent
EMBRYONIC STEM CELLS
Definition
Inner cell mass within fertilized cells.
Stage of Development
Blastocyst
Hollow ball of ~64 cells containing an
inner mass and trophoblast.
Importance
Able to be directed to any type of cell.
“Pluripotent”
BLASTOCYST
EMBRYONIC STEM CELLS
ADULT (Somatic) STEM CELLS
Definition
Tissue specific stem cells (Multipotent)
Purpose
Replacement
Damaged and injured tissue
Continually-replenished cells
Types
Bone
Bone Marrow Stromal Cells :Bone, Cartilage,Fibers
Hematopoietic Stem Cells : Blood Cells
Brain
Neural Stem Cells: Neurons, Astrocytes,
Oligodendrocytes
ADULT STEM CELLS
ADULT (Somatic) STEM CELLS
Plasticity (Transdifferentiation)
Definition
Ability to differentiate into multiple cell types.
Examples
Hematopoietic Stem Cells
Brain, Muscle (Cardiac and Skeletal), and
Liver Cells
Stromal Cells
Muscle Cells
Brain Cells
Blood and Skeletal Muscle
PLASTICITY (TRANSDIFFERENTIATION)
CANCER STEM CELLS
Teratocarcinomas (Teratomas)
Definition
Germ cell tumor with mixed differentiated
tissue and undifferentiated tissue
Example
Leukemia
Acute
Increased growth in an early stem cell
Chronic
Decreased response to death or
differentiation in a stem cell
Fundamental Remaining Questions
1) Does one common type of stem cell migrate
to different organs and repair tissue or are
there multiple types of stem cells?
2) Does every organ have stem cells (some of
which have not yet been discovered)?
3) Are the stem cells programmed to divide a
finite number of times or do they have
unlimited cell proliferation capacity?
CELL TECHNOLOGY
Cloning
Definition
Duplicating biological material
Types
Reproductive
Therapeutic
DNA (Recombinant Technology)
REPRODUCTIVE CLONING
Definition
Production of an organism that is genetically
identical to an original donor.
Pseudo-clone
Clone has genetic material from mitochondria.
Problems
Incompleteness of genomic imprinting
Process
Somatic cell nuclear transfer (SCNT)
SOMATIC CELL NUCLEAR TRANSFER
Process
1) Remove mammary cell from donor and starve.
2) Remove egg cell from a different donor and
enucleate.
3) Place mammary cell into egg cell.
4) Apply a brief shock to cause mammary cell
contents to mix with egg cell contents.
5) Allow cell to go through mitosis.
6) Implant into a surrogate sheep.
REPRODUCTIVE CLONING
THERAPEUTIC CLONING
Definition
Producing a blastocyst from a patient’s
somatic cells to be used for therapy.
Process
Somatic Cell Nuclear Transfer
Extract inner cell mass at blastocystic stage
Use cells to grow tissue or organs
Importance
Cells will not be rejected
RECOMBINANT DNA TECHNOLOGY
Definition
Excising DNA of interest from one genome and
inserting it into a foreign genome.
Process
Genetic Engineering
Biotechnology: Using genetic engineering to
create biological systems that produce a
desired product.
Importance
Drugs and medications
Genome enhancement
Fig. 24.15
RECOMBINANT DNA TECHNOLOGY
Steps
(1) DNA Isolation
a) Isolate foreign DNA from desired cell.
b) Isolate DNA plasmid vector from bacteria.
(2) DNA Fragmentation
a)Cut desired gene from foreign DNA using
“Restriction enzymes”.
b) Open plasmid using “Restriction enzymes” to
form a gap for DNA insertion.
RESTRICTION ENZYMES
RECOMBINANT DNA TECHNOLOGY
Steps
(3) Plasmid Recombination
Insert the foreign gene into the gap of the
plasmid by complementary base pairing
of the sticky ends and sealing with DNA
ligase.
(4) Recombinant Plasmid Uptake
Plasmid is taken up by bacteria through
transformation.
RESTRICTION ENZYMES
RECOMBINANT DNA TECHNOLOGY
Steps
(5) Plasmid Replication
Bacterial cell is replicated producing desired DNA
clones.
(6) Gene Isolation
DNA sequences can be cut from Plasmids and
added to other genomes.
Protein Production
Bacteria can be put into a desired environment to
produce desired protein.