ex 3 lec 3

Instructor's Announcement

• Instructor will be absent on Friday for personal reasons (visiting family).

• Video will be posted to cover material on eukaryotic topics, mainly fungi.

Blackboard Issues

• Exam two visibility issue on Blackboard was fixed.

• Students can now take exam two until the day before exam three.

Prokaryotic Diversity Overview

• Prokaryotic Diversity: Main focus on clades of microorganisms.

• Key Takeaway: Only important to remember what is discussed in class; detailed memorization of all microorganisms in the textbook is not required.

• Proteobacteria: Covered classes alpha, beta, gamma, delta, epsilon.

  • Epsilon Proteobacteria:

  • Campylobacter jejuni: Cause of food poisoning and linked to Guillain-Barré syndrome, an autoimmune condition leading to peripheral paralysis.

  • Helicobacter pylori:

  • Linked to peptic ulcer disease and gastric cancer.

  • Rediscoveries by Drs. Warren and Marshall linking gastrointestinal issues to this bacterium.

  • Demonstrated virulence by self-experimentation where drinking the bacterium led to ulcer formation, which was cured by antibiotics.

  • Helicobacter survives stomach acid by producing urease, creating a neutral zone around itself, leading to chronic gastric infection.

Gram Negative and Photosynthetic Bacteria

• Non-Proteobacteria Gram Negative Phyla: Includes Cyanobacteria.

  • Cyanobacteria: Important for global oxygen production and can produce dangerous neurotoxins (e.g., in Australia).

  • Observation of toxic strains in nature and their careful handling is essential due to potential risks to livestock.

Gram Positive Bacteria

• Two Major Phyla: Firmicutes and Actinobacteria.

  • Firmicutes (Low GC content): Includes:

  • Clostridium botulinum: Produces neurotoxin causing flaccid paralysis.

  • Clostridium tetani: Causes spastic paralysis (tetanus), significant morbidity worldwide.

  • Actinobacteria (High GC content): Include:

  • Mycobacterium tuberculosis: Re-emerged as a major health concern due to drug resistance.

  • Mycobacterium leprae: Causes leprosy; incidence decreasing but still present.

Notable Infections and Disease Agents

• Staphylococcus aureus:

  • Commonly found in humans, with issues like MRSA and toxic shock syndrome.

  • Linked to severe wound infections and resistance to treatment.

• Streptococcus:

  • A potent pathogen causing serious conditions like pneumonia, rheumatic fever, and wound infections.

  • More dangerous in terms of caused diseases compared to Staphylococcus due to its effects rather than drug resistance.

Unique Bacterial Structures and Pathologies

• Epilopissium: Large prokaryotic cell observed in the gut of fish, notable due to its size.

• Thiomargarita: Another exceptionally large prokaryote, showing diversity among prokaryotic life.

• Mycoplasma: Extremely small bacteria, such as Mycoplasma pneumoniae, causing mild walking pneumonia.

Chlamydia and Spirochetes

• Chlamydia:

  • Obligate intracellular pathogen, leading to common STDs; often asymptomatic in males, with serious implications for women (e.g., infertility).

• Spirochetes: Include pathogens like Borrelia burgdorferi (Lyme disease) and Treponema pallidum (syphilis).

Prevention and Public Health Connection

• Emphasis on vaccination (DTaP for diphtheria) and recognizing the resurgence of diseases that were once under control.

• Importance of proper medical care and public awareness in preventing diseases linked to bacteria.

Summary of Key Points

• Understanding how bacteria evolve, their environments, and health impacts.

• Recognize the role of gram bacteria in disease prevalence and treatment challenges.

• Stay informed on novel findings regarding bacterial behavior and pathogenicity, particularly in relation to human health.