Environmental Forensics Flashcards
What is Forensic Environmental Profiling?
using the presence of certain proxy indicators (e.g. bacteria, pollen, algae) as they are fragments o their original environment
What are the 3 domains of life?
Bacteria, Archaea, Eukaryota
Define autotrophic
make their own energy/build cellular structures omCO2 in the air
Define heterotrophic
eat other things/ obtain carbon from breaking down complex organic compounds
How are microbes classified using macroscopic features?
- colony shape
- colony size
- colour
- smell
How are microbes classified using microscopic features?
- shape i.e. rod, cocci, spiral
- chain forming or not
- presence of flagella
How are microbes classified using other features?
- staining i.e. gram -ve
- growth on different substrates
- biochemical testing
- DNA testing
Describe and explain the purpose of flagella, fimbriae and pilli
- Flagella: ‘tails’, rotate like propellers
- Fimbriae: little hairs all over, allows sticking to surfaces
- Pilli: longer than fimbriae, allow genetic exchange between cells
What is an endospore?
cells containing dehydrated cell organelles, allowing for long term storage, produced under stress as survival mechanism
What are endospores resistant to and why?
- heat, dessication (drying up), harsh chemicals, radiation
- spore coat consists f many cross-linked proteins
How are endospores reactivated?
add water
What do endospore cortexes consist of?
Peptidoglycan (murein)
What are the differences between gram-positive and gram-negative bacteria?
- Gram +ve have a thick peptidoglycan layer
- Gram -ve have 2 cytoplasmic membranes separated by periplasm, with a thin layer of peptidoglycan
What colour do gram-positive and gram-negative bacteria turn when using a gram stain?
+ve purple (dye gets trapped within structure)
-ve pink
What are some uses of microorganisms?
- decomposers
- biofuel production
- fermentation of alcohol/food
- produce human proteins i.e. insulin
- produce antibiotics/enzymes/chemicals
What do bacteria do within the human body?
- digestion/vitamin production
- influence susceptibility to illness/disorders
- influence response to drug treatments
What factors affect microbial communities?
- temp
- pH
- salinity
- pressure
- nutrient avaliability
How might microbes be used forensically?
- can be used like flies to identify what is usually present in the environment
- identify if item or body has been moved
- microbial succession after death for PMI estimation
- identification of clandestine graves through soil profiling
What is Forensic Microbiology?
use of microbial evidence related to bioterrorism. bio crimes, hoaxes, or accidental release of toxins and biological agents.
What makes a biological weapon effective?
- effective in low doses
- highly contagious
- short incubation time
- easily dispersed i.e. water or person-to-person
- target population has little to no immunity or access to immunisation
- attacker must have a mans to protect themselves
What is biological warfare?
The use of biological agents to incapacitate or kill a military or civilian population in an act of war or terrorism
What is a biological weapon?
Organism or toxin that:
- is easy to produce/deliver
- safe for use by the offensive forces
- affects individuals in a reproducible and consistent manner
How is anthrax an effective bioweapon?
- has endospores
- infects via contact, inhalation
What is Forensic Palynology?
Study of pollen grains, spores and application to forensic investigations
