ex 3 lec 3

Exam Information

• Upcoming exams: The next exam is in two weeks (Exam 2.13).
• Exam 3 will take place later, giving students ample time to prepare.

Lecture Overview

• Starting with eukaryotic diversity.
• Moved on to topics of disease and epidemiology.
• Noted the Irish Potato Famine as a historical example of disaster management and infrastructure failure.

Irish Potato Famine

• Affected 10% of the American population (Irish descent).
• Lessons in disaster preparedness and the importance of infrastructure for distribution during crises.
  • U.S. sent corn to Ireland, but inefficiencies prevented proper distribution.
  • High tariffs in England and Ireland hampered aid delivery.
• Highlighted the importance of learning from past disasters to inform current policies, particularly regarding FEMA.

Lichens

• Definition: A mutualistic organism consisting of algae (photosynthetic) and fungi.
• Can survive in extreme conditions, including polar regions.
  • Important food source for reindeer.
• Characteristics:
  • Fungi provide support and nutrient absorption, algae perform photosynthesis.
  • Slow-growing.
  • No known agricultural diseases or commercial significance.

Slime Molds

• Two main types: Cellular slime molds and Plasmodial slime molds.

Cellular Slime Molds

• Exist in an amoeboid state, living as saprophytes in dark, moist environments.
• When conditions dry, cells secrete signaling molecules and form a slug that migrates to more favorable areas for reproducing (fruiting bodies).
• Can appear in unexpected places, such as damp basements.

Plasmodial Slime Molds

• Multinucleated blobs that can often be seen with the naked eye.
• Move via cytoplasmic streaming; adept at creating pathways, utilized in civil engineering.
• Prefer dark, moist conditions, often brightly colored.

Protozoans

• Unicellular eukaryotes classified historically into the same kingdom; exhibit vast genetic diversity.

Characteristics

• Chemoheterotrophic, sometimes photosynthetic.
• Generally aerobic but can exist anaerobically due to fermentation pathways.
• Reproduce asexually and sexually (fission, schizogony).
• Can form resistant cysts for survival under harsh conditions.

Notable Protozoans

1. Trichomonas vaginalis (Archaeozoa)
   • Common STI, often mild symptoms, exists anaerobically.
2. Giardia lamblia
   • Waterborne pathogen, causes gastrointestinal distress; fecal-oral transmission, often severe symptoms.
3. Amoebozoa
   • Amoebic dysentery can occur; rare but severe when contracted.
4. Apicomplexa
   • Includes malaria and is a leading cause of human death.
   • Complex life cycle involves stages in mosquito and human hosts.
   • Often causes cyclical fever through red blood cell lysis and oxygen loss in the body.

Malaria Details

• Caused by malaria protozoan species (Plasmodium).
• Significant historical and modern impact on human health.
  • Infection can lead to severe complications and mortality; occurs every 45 seconds.
• Prevention includes controlling mosquito populations and treatment with antimalarials.

Cryptosporidium

• Waterborne parasite linked to fecal contamination.
• Outbreaks in recreational waters; resistant to chlorination.
• Symptoms include severe gastrointestinal distress.

Trypanosomes

• Old World: Causes African sleeping sickness, prevented REM sleep, spread via tsetse fly.
• New World (Chagas Disease): Spread by kissing bugs, latent infections, can lead to serious health issues years later.

Conclusion

• Future considerations in the context of protozoan diseases: prevention through vector control and treatment development.
• Importance of learning from historical cases to inform modern disease management.