Final Investigation Notes

Recombinant DNA

Definition: DNA made by inserting the gene of interest, from a healthy donor, into a DNA molecule in a patient, scientists use vectors (bacteriophages or plasmids) and restriction and ligase enzymes.

→ Bacteriophage: Viruses used as a vector to infect bacterial cells

→ Plasmid: Extrachromosomal circular strands of DNA found in bacteria, capable of self replication. Placed back into bacteria and reproduces, amplifying amount of DNA available.

→ Restriction Enzyme: An enzyme that cuts long strands of DNA into shorter pieces at recognition sites, specific sequence of bases.

→ DNA Ligase: Enzyme capable of rejoining or combining two pieces of DNA

→ Ligation: The process where DNA is joined together

Used For: Insulin, human growth hormone, interferon, hepatitis B vaccine

Steps:

  1. Gene of interest removed from “healthy donor” using restriction enzyme.

    1. Plasmid (vector) removed from bacteria and cut with some restriction enzyme

    2. Cut plasmid and “gene of interest” mixed and ligated together in a process called ligation.

    3. rDNA (plasmid + gene of interest) inserted back into bacteria.

    4. Bacteria multiply and transcribe and translate gene of interest

    5. Gene of interest protein/hormone is collected, purified and bottled.

    6. Bottled/hormone injected into patient

Cell Replacement Therapy

Definition: Cell replacement therapy involves the transfer of cells, with the relevant and healthy function, to the patient. Healthy cells derived from stem cells are introduced into the body.

Used For: Any disorder involving loss of or injury to normal cells

Steps:

  1. Take some cells (i.e. skin cells) from patient

  2. Add some induced pluripotent factors

  3. Cells created are undifferentiated, capable by mitosis to turn into any cell

  4. Force these cells to differentiate to the desired cell (neuron (or nervous tissue))

  5. Transplant cells back into patient healthy cells (Cells from you, immune system will not reject. If there was a genetic factor)


Gene Therapy

Definition: Gene therapy involves the transfer of genetic material, and the uptake of that material, into cell nuclei of the body. Targets diseases caused by single gene defects.

Steps (In Vitro):

  1. Cells from patient with the faulty gene are removed

  2. Gene of interest removed from “healthy donor” using restriction enzyme.

  3. Cut the DNA of a vector DNA (virus) with the same restriction enzyme

  4. The vector DNA and “gene of interest” is combined by DNA ligase in ligation.

  5. Viral DNA and gene of interest inserted back into virus.

  6. Virus infects patient’s cells with gene of interest, genetically altering the patient’s cells

  7. Altered cells are placed back into patient.

  8. Patient’s “new” cells transcribe and translate gene of interest

Steps (In Vivo):

  1. Gene of interest removed from “healthy donor” using restriction enzyme.

  2. Cut the DNA of a vector DNA (virus) with the same restriction enzyme

  3. The vector DNA and “gene of interest” is combined by DNA ligase in ligation.

  4. Altered virus is injected into the patient

  5. Virus infects patient’s cells with gene of interest, genetically altering the patient’s cells

  6. Patient’s “new” cells can produce the desired protein


Alzheimer’s Disease

Causes: An abnormal build-up of proteins in and around brain cells; such as amyloid beta and tau. A combination of age-related changes in the brain, along with genetic, environmental and lifestyle factors. It is a neurodegenerative disease.

Stem Cells: Neural

Symptoms:

→ Early Symptoms: Memory lapses (poor judgement, less flexibility, etc), mood changes (increased anxiety or agitation), periods of confusion.

→ Middle-stage symptoms: Poor memory, increasing confusion and disorientation, delusions, paranoia, problems with speech or language, disturbed sleep, changes in mood, hallucinations.

→ Later symptoms: Difficulty eating, swallowing and moving around, hallucinations and delusions, weight loss, urinary or bowel incontinence, gradual loss of speech, significant memory difficulties.

Potential Use of Cell Replacement Therapy: Transplanting neural stem cells into the brain of an Alzheimer’s patient might offer temporary help before more neurons are lost. Researchers are using induced pluripotent stem cells to grow neurons that have the same genetic background as people affected by AD so they can study the disease.


Parkinson’s Disease

Causes: A loss of nerve cells in the part of the brain called the substantia nigra. This part of the brain is responsible for producing dopamine (which controls and co-ordinates body movements). A loss of nerve cells is believed to be caused by a combination of genetic changes and environmental factors.

Stem Cells: Pluripotent

Symptoms:

→ Main Symptoms: Tremors, slowness of movement (bradykinesia) and muscular stiffness (rigidity)

→ Physical Symptoms: Balance problems, loss of sense of smell (anosmia), nerve pain, problems urinating, constipation, swallowing difficulties (dysphagia), excessive production of saliva, insomnia

→ Cognitive and Psychiatric Symptoms: Depression and anxiety, mild cognitive impairment, dementia

Potential Use of Cell Replacement Therapy: Dopamine cell replacement transplantation with embryonic stem cells and/or induced pluripotent stem cells.