Carriers of Disease

1
Carriers of Disease

• Microbes, Germs and Other Scary Things

2
Bacteria

• Prokaryotic, monera
• 2 billion yrs
• 1st life on earth
• They change and adapt to the environment
• No cell membrane or nucleus
• Have cell wall
• Many different structures

3
Habitat

• Extremes
• Hot
• Cold
• Acidic
• Alkaline
• Everywhere on earth
• Minority cause disease
• Majority are essential to life on earth

4
Diversity

• 2 groups
• Archeabacteria halophytes, themoacidophiles,
  Methogens poisoned by O2
• Eubacteria all others
• Pathogenic eubacteria cause about ½ of all human
  disease
• Some destroy tissue
• Exotoxins secrete substances that cause disease
• Endotoxins parts of the cells cause fever or
  shock

5
Motility

• ½ make direct movement
• Flagella most common form of movement,
  extension of plasma membrane
• Spirochetes spiral shaped that may have slimy
  chemicals excreted and a flagella
• Taxis have an attraction to chemical that may
  be beneficial or harmful

6
Virus

• Simplest form of life
• Argument can be made that they may not be living
• 1st discovered by Dr. Mayor in tobacco plants
• Very small 20nm diameter

7

• Consist of viral genes enclosed in capsid a
  protein shell
• There are multiple types of protein
• Envelopes covering on capsid taken from the
  membrane of host
• Phages virus that infect bacteria

8
RNA viruses

• Single strand of nucleaic acid molecule involved
  in protein synthesis
• Structure is specified by DNA
• Retrovirus most complicated reproduction
• Can reverse DNA to RNA
• New DNA integrates into host cell

9
Evolutionary origins

• Evolved after 1st cells from fragments of
  nucleacic acid
• Developed capsid to promote infection
• Viral genomes plasmids transposes DNA
  segments that move along genome
• Virus replicate using the entire cell it infects

10
Prion

• Cause disease but arent bacteria, virus,
  parasite or fungi
• They are protein and not alive
• 1986 1st public awareness with onset of Mad-Cow
  Disease
• Enter cell where they convert normal protein
  found within cell into prions like themselves

11

• When normal cell is transformed into prion the
  amino acids are folded into alpha helical
  structures and relax into beta sheets
• Prion then clog cells which decreases function or
  stops the cell from functioning all together
• In brain tissue prion-bloated brain cells dies
  and release prion into tissue leaving holes in
  brain matter
• Cause disease call spongiform encephalopathies

12
Parasites

• Single cell or multicell organism that feeds off
  host
• Can survive only if host lives
• Causes disease that are usually not fatal
• Too many variety to list

13
Fungi

• Ecosystem would collapse without fungi
• Decomposers
• Recycles chemical elements in the environment
• Positive uses for humans
• Food
• Cultures to produce antibiotics
• Makes bread rise
• Ferments to create beer and wine

14
Characteristic

• Eukaryote, multicellular
• Heterotrophic
• Excretes enzymes that break down molecules which
  it then absorbs\
• Can be parasitic or mutualistic

15
Unique Lifestyles

• Molds grow as parasites on variety of
  substrates
• Ex. bread mold
• Yeast inhabit moist environments or liquids
• Ex. - Candida

16
Pathogenic Yeast in Humans

• Athletes foot
• Ringworm
• Vaginal yeast infections
• Lung infections
• Nail infection