BIOL 200 Exam 3 Vocab

Genetic engineering

Alteration of an organism's genetics to achieve desired traits

Recombinant DNA

DNA produced from cutting and inserting DNA from one organism into the DNA of another organism

Transgenic organism

Organism with recombinant DNA (has genes from multiple organisms)

Restriction enzymes (endonucleases)

Enzyme that cuts DNA at a specific sequence of nucleotides to make recombinant DNA

Recognition sites

A sequence of DNA where a restriction enzyme cuts

Ligases

Join fragments when inserting DNA fragment (gene) into a vector (ex. plasmid)

- Do the opposite of restriction enzymes

Transformation & transfection

- Transformation: bacteria (bacteria takes up naked DNA)

- Transfection: eukaryotes (introduction of recombinant DNA molecules into eukaryotic hosts)

Electrophoresis

- Separating based on charge and size with semi-solid media that creates a grid to slow down bigger things

- Smallest DNA travel down the furthest, biggest DNA travel least

- Pulled down by electrical charge

- Use DNA ladder as a control to compare size and number of base pairs

Reverse-transcription & reverse transcriptase

- Reverse transcription: the process of making DNA from RNA template (RNA to DNA + RNA)

- Done by reverse transcriptase

Polymerase chain reaction (PCR)

- Technique for amplifying (creating millions of copies of) DNA in vitro (tubes) by using thermal cycler with special primers, DNA polymerase molecules, and nucleotides

1. Denaturation at 95° C - double-stranded DNA split into single strands

2. Annealing at 55° C - primers bind/anneal to complementary sequence

3. Extension at 72° C - DNA polymerase synthesizes new strands by adding on to 3' end

- Ends in two copies of original DNA

RT-PCR

- Reverse transcriptase PCR

- Allows PCR of RNA

- RNA is converted to DNA with reverse transcriptase and then PCR can be done

DNA sequencing

- Determining the order of base pairs in DNA

- Takes a piece of DNA and creates a graphical output that can be read as a sequence of letters

Gene therapy

- The insertion of working copies of a gene into the cells of a person with a genetic disorder in an attempt to correct the disorder

- Has not been very successful and we are hesitant to use because can cause systemic problems in humans

- Ex. Human missing gene so gene is packed into virus then picked up by human cells and protein is expressed

Protocols for control of microbial growth

Inanimate objects (fomites)

- Sterilization: kills all cells, endospores, and viruses; gold standard

- Disinfection: reduces or destroys microbial load with heat or antimicrobial chemicals

- Sanitization: cleaning, reduces microbial load to safe levels for public health with heat or antimicrobial chemicals

Living tissue

- Antisepsis: reduces microbial load with antimicrobial chemicals; like disinfection

- Degerming: physical movement and use of chemicals to reduce microbial load (ex. scrubbing)

Fomites

Inanimate item that may have microbes and aid in disease transmission

Autoclave

Machine used for sterilization via high heat/high pressure and steam

- Like a pressure cooker

BSL

Biosafety levels

- BSL 1: don't cause disease in healthy hosts, minimal risk

- BSL 2: typically indigenous, associated with diseases of varying severity, moderate risk

- BSL 3: indigenous or exotic, can cause serious or potentially lethal diseases, respiratory transmission

- BSL 4: dangerous and exotic, high risk of aerosol-transmitted infection, frequently fatal without treatment or vaccines, few labs at this level

Aseptic

Protocol designed to prevent microbial spread or contamination to sterile objects

- Does not require sterile environment

Sterile

Completely free of microbes

- Sterile or not, no such thing as semi-sterile

-cidal & -static

- cidal: kills microbes

- static: stops microbial growth but does not kill (steady, stable)

Pasteurization

Heating food to reduce microbial numbers

D-value (DRV)

Time to kill 90% of a bacterial population (time to go down one magnitude, like 10^6 to 10^5)

Chemotherapy

Using chemicals for treatment

Drugs

Chemotherapeutic agents

Anti-microbial

Kills or inhibits microorganisms (bacteria, viruses, fungi, parasites

Antibiotic

Uses chemicals from another organism to kill bacteria

Penicillin

- Example of antibiotic/anti-microbial drug

- Has beta-lactam ring

- Targets cell wall

Beta-lactam

Ring (house with attached garage) makes drug (ex. penicillin) antibacterial by interfering with peptidoglycan synthesis, targeting the cell wall

Narrow & broad spectrum drugs

- Narrow: targets more specific aspect (ex. gram-negative bacteria only); targets basic life processes; less side effects

- Broad: kill a wide range of bacteria; can cause superinfection

Superinfection

Secondary infection that is caused by long-term use of broad spectrum antimicrobial drugs

- Susceptible bacteria are killed but resistant are left

Dosage

Amount of drug that is administered

Route of administration

How drug is given

- Oral: delay in getting into blood stream, then rise, and gradual decline

- Intramuscular (IM): works quicker than oral but similar curve

- Intravenous (IV): high concentration in blood quickly and drops rapidly

Selective toxicity

Kill microbes without harming patient

Mode of action

The way that a drug kills or inhibits microbes (what it targets)

- Cell membrane & ribosomes: harder/less used because humans have cell membrane and same 70S ribosomes in mitochondria)

- Metabolic pathways: common one is folic acid because humans get through diet but bacteria synthesize own

- DNA synthesis/RNA transcription

- Cell wall: easiest because humans don't have peptidoglycan cell walls

Antifungal, anti-helminthic, anti-protozan, & anti-viral

Drugs that target _________

- Fungi, protozoa, and helminths harder to kills than bacteria because they are eukaryotic

- Antifungals target ergosterol in cell membrane (metabolic pathway)

- Protozoa: single celled eukaryotic organisms

- Viruses hard to target becuase they are inside human cells

- Antiviral drugs interrupt virus lifecycle (inhibit fusion of enveloped virus to cell, reverse transcription, exit of virus, etc.)

Drug resistance

Happens because

- Cells block entry/penetration of drug

- Cells selectively pump drugs out

- Enzyme inactivation of drug (cuts up)

- Target modification/mutation so drug can't stick or work

- Target overproduction - if ribosomes are targeted and half inhibited, just make more ribosomes

Mechanisms susceptibility testing

uses phenotypic methods to measure growth inhibition (like MIC and disk diffusion) or genotypic methods to detect specific resistance genes (like PCR) to determine if an infection is Susceptible, Intermediate, or Resistant to a drug.

Antimicrobial drug discovery

identifies new antimicrobial agents by screening chemical libraries for growth inhibition or targeting specific essential proteins to overcome existing resistance mechanisms

Disease

Deviation from the normal structure and function of the body

Infection

Microorganism enters host

Sign & sympyom

- Sign: Objective, observed, and measured

- Ex. fever

- Sympyom: subjective and reported

- Ex. headache

Syndrome

Collection of associated signs and symptoms; what a disease is called starting out

Asymptomatic

Showing no symptoms or signs of infection

Infectious

Caused by a pathogen

Communicable, noncommunicable, & contagious

- Communicable: can be transmitted from one person to another; ex. STDs

- Noncommunicable: can't be transmitted from one person to another; ex. tetanus

- Contagious: highly communicable; ex. measles

Entry & exit

How pathogens get in & out of body; any hole in the body, either pre-existing or created

- Ex. respiratory system, oral-fecal route

Nosocomial/HAI

Healthcare acquired infection

Zoonotic disease

Disease transmitted from animals to humans

Stages of acute illness

- Incubation: no signs and symptoms, pathogen is new and low in numbers

- Prodromal: vague and nonspecific effects (feeling tired, sore, etc.), pathogen numbers rising

- Illness: most severe and specific effects, most pathogens; peak where both of these things highest during this stage

- Convalescence: pathogens gone but host may still be healing/repairing

Acute, chronic, & latent

- Acute: infection that goes away and doesn't last long; ex. influenza

- Chronic: lasts months, years, or even longer; ex. HIV

- Latent: disease goes into dormant state and can come back and reactivate later; ex. chickenpox/shingles virus

Germ theory

Particular germs cause particular diseases

Primary & secondary infections

- Primary: initial infection produced by a pathogen

- Secondary: second infection that develops after primary infection due to compromised immune defenses or antibiotics

Etiology & etiologic agent

- Etiology: the cause of a disease

- Etiologic agent: pathogen or substance that causes a disease

Pathogenicity

Ability of a microorganism to cause disease

Virulence

Degree of pathogenicity

Infectious dose & lethal dose

- ID 50: median infectious dose; concentration that will cause infection in 50%

- LD 50: median lethal dose; concentration that will cause death in 50%

Exoenzymes

Enzymes secreted out of a cell by microbes that break things down and aid microbes in invading and infecting host cells

Endotoxins, exotoxins, & enterotoxins

- Endotoxins: parts of cell that come from cell damage; lipid A component of lipopolysachharides; heat stable; less specific effects, high ID/LD 50

- Exotoxins: proteins exported out of healthy cell; more specific effect; very potent - low ID/LD 50

- Enterotoxins: make gut upset and cause vomiting/diarrhea

Bacteremia, toxemia, and viremia

_________ in the blood

Septicemia

Growth/multiplication of bacteria in the blood

Antigenic drift & antigenic shift

- Antigenic drift: slight variations due to mutations that make cells look different

- Antigenic shift: major variation; ex. two viruses infect the same host cell and combine to make a new virus

Koch's postulates

1. Suspected pathogen is found in every case in disease and not in healthy individuals

2. Suspected pathogen is isolated and grown in a pure culture

3. Healthy subject is inoculated with culture and becomes diseased

4. Same suspected pathogen can be isolated again from inoculated subject

Virulence factors

Tools used to make a microbe more virulent; more = more pathogenic

- Adhesins: allow bacteria to stick to cells in host

- Ability to form a biofilm

- Get into blood & multiply

- Toxins: biological poisons that help with damage and infection

- Exoenzymes

- Factors that help evade immune system - capsule, producing extra outer layers, etc.

Epidemiology

Study of epidemics; the science underlying public health; uses data to inform public health

Morbidity & mortality

- Morbidity: in a state of illness

- Mortality: death

Prevalence & incidence

- Prevalence: total number affected in a population; higher than incidence

- Incidence: number of new cases (ex. new cases today)

Sporadic & endemic diseases

- Sporadic: rare, randomly occurring without geographic focus

- Endemic: occur at constant, low (background) level within population

Epidemic & pandemic

- Epidemic: outbreak of disease at a level significantly higher than expected on one continent

- Pandemic: epidemic spreads to multiple continents

CDC

Center for Disease Control - epidemiologists for the US

Notifiable diseases

Reported to the CDC when someone is diagnosed with a notifiable disease

- Ex. HIV, chlamydia, gonorrhea

MMWR

- Morbidity and Mortality Weekly Report from CDC

- Tracks and reports the incidence of notifiable diseases

Reservoir

Somewhere where microbes live and are naturally found

Carrier

Person or animal that carries a pathogen and can pass it on

Host

Organism that provides sustenance and suitable environment for a pathogen

Direct & indirect contact

- Direct: physical contact between infected and susceptible person; ex. kissing, shaking hands

- Indirect: transfer via fomite; ex. doorknob, syringe

Droplet

Form of direct transmission where sneezed or coughed droplets of mucus land on the new host

Vehicle transmission

Pathogen is transferred from one host to next by soil, air, water, or food

Vector transmission

Carrier takes infectious agent to new host

Biological & mechanical vector

- Biological: carrier is infected; ex. dog with rabies bites a person and the person becomes infected

- Mechanical: organism carriers and transfers pathogen without being infected; ex. dog rolls in something dead and transfers disease to owner's hands

Transmission

Transfer, such as of a disease, from one person to another

Arthropod

Insect, spider, mite, etc; most common biological vector

Quarantine

The isolation of an individual for the purpose of preventing the spread of disease

WHO

World Health Organization

- UN agency to coordinate international health activities and to help governments improve health services

(Re-)emerging diseases

- Emerging: new diseases, within last 20 years; ex. COVID 19

- Re-emerging: previously controlled diseases that come back; ex. measles