ex 3 lec 2

  • Exam Logistics

    • Paper copy of exam number two available.
    • Students encouraged to take the exam promptly as the class will move on to new content.

  • Previous Material Overview

    • Discussion of BRE (Biotechnological Relevance) – A small slide set classification discussing procedures like:
    • PCR (Polymerase Chain Reaction)
    • Next Generation Sequencing
    • Microarrays
    • MALDI-TOF (Matrix-Assisted Laser Desorption/Ionization Time of Flight)
    • Emphasized that biotechnology and the technologies used are complex subjects warranting deeper exploration in standalone courses.

  • Upcoming Content: Prokaryotic Diversity

    • Loaded chapter filled with dense information and classifications.
    • Students do not need to memorize all species; focus on select interesting examples highlighted by the instructor.
    • Recognizing general categories such as:
    • Importance in agriculture and environmental cycles (sulfur and nitrogen cycles).

  • Taxonomic Classification

    • Prokaryotes classified based on the sequence of the 16S ribosomal RNA gene, which provides a stable evolutionary marker.
    • Classification is dynamic, constantly evolving with new discoveries in microbiology.
    • For example, there are currently 24 major phyla in the bacterial domain; focus will be on six, primarily the proteobacteria.

  • Proteobacteria Overview

    • Dominates discussions due to the importance of gram-negative bacteria (largest group).
    • Discusses notable classes: alpha, beta, gamma, delta, and epsilon proteobacteria.

  • Alpha Proteobacteria

    • Includes organisms involved in agricultural processes, specifically nitrogen fixation.
    • Notable genera:
    • Rhizobium – Involved in nitrogen fixation.
    • Agrobacterium tumefaciens – Plant pathogen pivotal in creating genetically modified organisms (GMOs).
      • Causes crown gall disease in plants by transferring plasmid DNA to plant cells.
    • Caulobacter – Exhibits a unique life cycle with motile and stalked stages.
      • Changes in structure allow adaptation to nutrient-rich environments.

  • Beta Proteobacteria

    • Organisms primarily serve as saprophytes, facilitating the decomposition of organic matter.
    • Thiobacillus involved in the sulfur cycle and Nitrosomonas in the nitrogen cycle (oxidizes ammonia to nitrite).
    • Neisseria gonorrhoeae causes gonorrhea, a major sexually transmitted infection.

  • Gamma Proteobacteria

    • Key members include:
    • Vibrio cholerae (causes cholera).
    • Pseudomonas (opportunistic pathogen prevalent in various environments).
      • Notable for its resistance to disinfectants and ability to cause serious infections in immunocompromised individuals.
    • Yersinia pestis (causes bubonic plague, historically devastating pandemics).
      • Transmission primarily through fleas but can also become pneumonic.

  • Delta Proteobacteria

    • Focus on Deltaproteobacteria with members that infect other bacteria.
    • Existence of bacteria that can infect other bacteria showcases unique ecological interactions.

  • Epsilon Proteobacteria

    • Includes Campylobacter jejuni, which is associated with foodborne illness and potential links to Guillain-Barré syndrome.
    • Helicobacter pylori is noted for its role in peptic ulcers and gastric cancer.

  • Conclusion and Quiz Reminder

    • Remaining topics to cover will continue on Wednesday, including a quiz for review.