No change in protein. Most Mutations are silent! Can occur in a noncoding area. Can mutate a promoter and alter transcription levels.
change in amino acid (Sickle Cell anemia)
change in frame. Change in stop codon making nonfunctional proteins eventually degrade the cell.
Mutation Related Diseases
Cancer Genetic diseases
misregulation of the cell cycle. Mutations can alter the function of the cell cycle. Tumor-suppressor genes can be mutated to become nonfunctional. HIGH RISK! Requires multiple mutations.
Genes can be mutated. the DNA sequence for a gene gets errors, causing it to make a different protein. Can be inherited by family members. EX. Cystic fibrosis and Hemophilia.
Cause of Mutations
Radiation Chemicals Reactive Oxygen Species DNA replication Errors (Not often)
a chemical that causes an increase in the mutation rate
a chemical that can cause cancer. Most are Mutagens but not ALL
Uses bacteria to determine if a chemical compound is a mutagen. (EX. Salmonella with a mutant histidine synthesis gene. Salmonella requires histidine to grow. Some Salmonella revert back to normal. Adding a mutagen will increase the reversion chance.) Chemicals that cause reversions tend to cause cancer.
Genes can be taken from one organism and added to another.
Can cut DNA. The cut pieces can be repaired with Ligase. Discovered in 1972 and partially banned in 1975.
Green Fluorescent Protein (GFP)
Come from Jelly fish. Added to organisms. Very useful for mapping where genes are expressed.
-Carbon dioxide is removed to form Acetaldehyde -Acetaldehyde is reduced to form ethanol (receives electrons).
-soluble in fats and waters -Increase membrane fluidity, loose integrity -no wine of beer over 12% ethanol -Higher concentrations are made from distillation -Depressant for some and a stimulant for others
antifreeze. EXTRA OH
rubbing alcohol. ONE Carbon. Produced by wood fermentation. causes Blindness
Alcohol Flush Reaction
turn bright red because Acetaldehyde is not being broken down effectively. Jump to hangover state.
transmits an electrochemical signal from the cell-body to the axon.
space where the dendrite of one neuron meets the axon of another neuron.
-prevent the formation of nucleic acids by inhibiting the synthesis of folic acid. -PABA- precursor to make folic acid which sulfa drugs prevent -Competitive inhibitor.
-include ciprofloxacin -inhibits DNA gyrase from resealing nicks
-activated by flavodoxin -damages DNA by causing nicks - humans given the inactive form
RNA Synthesis Inhibitors:
-Binds to the B subunit of RNA polymerase -Blocks the emergence of mRNA (blocks pores) -prevents RNA from being created
General Causes of Antibiotic Resistance:
1. Overuse of Antibiotics 2. Misuse of Antibiotics 3. Human population density and interactions 4. Immune-suppressed individuals 5. Frequent Mutations 6. Bacterial populations densities 7. Short replication time 8. Horizontal Gene Transfer
5 Mechanisms fro Antibiotic Resistance
1. Restriction of Access 2. Enzymatic Inactivation 3. Target Modification 4. Failure to Activate 5. Alternate Pathway
found in gram negative outer membranes. Some antibiotics are too large to diffuse the membrane
Reduced uptake (restriction)
Some antibiotics gain access to the cell through receptors on the inner membrane can be mutated to not bind to the drug. RARE mechanism
Antibiotic Efflux Pump (restriction)
Removes the drug from the cell as it diffuses in.
B-lactamase (Enzyme inactivation)
Cleave the beta lactam ring Clavulanic acid- inactivated B-lactamase
Penicillin- Binding Protein Resistance (Target Modification)
Alters the shape of the protein so that penicillin can't fit into the binding site.
Vancomycin Resistance (Target Modification)
-Prevents the peptide interbridge from forming. -Vancomycin resistant bacteria can alter the peptide bond.
Metronidazole Resistance (Failure to activate)
-Bacteria can mutate to not express flavodoxin -mutate promoter region of gene itself
Sulfa drug resistance (Alternate pathway)
bacteria use another metabolic pathway to make folic acid
involves use of a virus; SAME species
Types of Viral Infection
1. The Lytic Cylce 2. The Lysogenic Cylce
The Lytic Cylce
bacteriophages replicate inside a cell and cause it to lyse
The Lysogenic cycle
the viruses integrate their DNA into the host genome. Pull of genes form the host as the virus leaves transfering genes to another organism. EX: Diphtheria
involves the up take of DNA/ PLASMIDS
small pieces of circular DNA Have a size of 2kb to 50kb (killa base)
The transposable element is moved. Transposon jumps from plasmid to chromosome
The transposable element is duplicated. Tansposon jumps into chromosome while in the plasmid and can replicate themselves.
any biological agent that can cause a disease. (prions, virus, bacteria) MOST microbes are NOT pathogens
ability of a pathogen to cause a disease
natural traits a pathogen can us to establish itself in a host. (Ex. Toxins)
Possible Reasons for Virulence:
1. bacteria have evolved to cause human disease (Primary pathogen) 2. Bacteria are attempting to create a non parasitic association, but fail. 3. Bacteria normally live in another niche, but have accidentally entered and caused an immune response.
Tuskegee Syphilis Experiment (ethical problem)
Black men with syphilis go untreated so that the government can track the progression of the disease.
Jewish Chronic Disease Hospital (ethical problem)
old people with dementia injected with cancer
Willowbrook State School (ethical problem)
Injected mentally disabled kids with hepatitis A without parents permission
50% Lethal Dose (LD 50)
amount of pathogenic bacteria required to cause a terminal infection in half of the animals LOWER LD50 MORE virulent
50% Infectious Dose (ID 50)
Dose of bacteria required to infect half of the animals. LOWER ID 50 MORE virulent
Germ Theory of Disease
Koch's postulates required to link a microorganism to a disease.
1. Microorganism must be found in all cases of the disease 2. It mush be isolated and grown in culture 3. It must reproduce the disease when introduced to a host 4. It must be reisolated from the host with the disease
1. Some strains of microbes are pathogenic while others are not. (Ex. E. coli) 2. Some microbes can be very difficult to culture (EX. Syphilis) 3. Genetics can make a person more or less susceptible to the disease 4. Age can also make someone more or less susceptilble 5. An animal model may not exist (ex. Cholera)
1. Non steroidal Anti-inflammatories 2. Helicobacter pylori
penetrates the mucus and adheres to the epithelial cells and produce urase in the stomach.
- motile with peritrichous flagella -moves with run and tumble motility -infects small intestine -causes gastroenteritis -Gram negative facultative anaerobe -survive water at cold temps
-incubation for a month -rash on abdomen -Bacteria travel from liver and spleen -Delirium and convulsions
-Typhoid Mary - Asymptomatic/ chronic carrier- no symptoms
component of cell wall causes inflammatory response
Pore-forming exotoxin (membrane disrupting)
forms pores in membrane with protiens composed of alpha helices and beta sheets
Phospholipase Exotoxin (membran disrupting)
Also called hemolysins or ctyolysins, can cleave the phosphate from the lipid disrupts the cell membrane. (EX. Gangreen)
-A (active)- has enzyme activity -B (binding)- binds to a receptor and moves A into the cell -A-B subunits separated by proteolysis -A chain can only get into a certain type of tissue because of B chain
organism that lives in a particular region. Not involved in pathogenic processes. Colonize particular regions so pathogens can't grow.
normally non pathogenic microbe can cause a disease
acquired in the hospital
-arid, acidic, aerobic -Staphylococcus epidermidis- forms biofilms on implants and catheters -Propioribactrium acnes- Anaerobic lives in pore and hair follicles
Staphylococcus aureus- 1/3 of people
Streptococcus mutans- tooth decay; ferments sucrose to lactic acid and creates dextran which allows a biofilm to form.
Urinary Tract Infection Causes:
1. More frequent in women 2. Travel upward along urinary tract 3. E. coli MOST common cause 4. Spermicides
-urine washed bacteria away - Type 1 Pili- allows E. coli to bind to the mucosa of the urethra.
-Gram positive Facultative anaerobe -Golden Cluster Seed -Infects cuts, glands, and hair follicles -may require surgery