Global Impact of Microbes_2024_Mahmood Alam

Global Impact of Microbes

• Presented by: Dr. Mahmood Alam

Aims

• Overview of critical topics related to microbes:

  • Microbes in the environment

  • Plastic degradation

  • Planktons in the sea

  • Microbes in technology (PCR, Restriction Enzymes, CRISPR-CAS)

  • Vaccines

  • Microbes in medicine (cancer therapeutics, antibiotics)

Life Strategies

• Foundation of Life: All life begins with microorganisms.

  • Key Components:

    • Energy

    • Carbon

  • Life Strategies:

    • Phototroph: Energy from light

    • Chemotroph: Energy from chemical oxidation

    • Autotroph: Uses CO2 directly

    • Heterotroph: Consumes organic compounds

Types of Organisms Based on Energy and Carbon Source

• Photoautotroph:

  • Energy from sunlight

  • Uses CO2

  • Examples: Plants, algae, cyanobacteria

• Chemoautotroph:

  • Energy from chemical oxidation

  • Uses CO2

  • Examples: Extremophiles

• Chemoheterotroph:

  • Energy from chemical oxidation

  • Uses pre-formed organic compounds

  • Example: Humans and animals

• Photoheterotroph:

  • Energy from sunlight

  • Uses pre-formed organic compounds

  • Examples: Purple/green non-sulfur bacteria

Temperature Preferences of Microbes

• Psychrophiles:

  • Optimal growth: < 15ºC

  • Example: Chlamydomonas nivalis, Listeria monocytogenes

• Mesophiles:

  • Optimal growth at body temperature

  • Includes many human pathogens

• Hyperthermophiles:

  • Thrives at > 70ºC

  • Requires high temperature for survival

  • Example: Thermus aquaticus

• Thermophiles:

  • Produce spores used as biological indicators for sterilization procedures.

Survival Strategies at Extreme Temperatures

• Cell Membrane Adaptations:

  • High Temperatures: Adaptation by solidifying fats (increase saturated fat content) to maintain membrane integrity.

  • Low Temperatures: Adaptation by increasing unsaturated fats to keep the membrane interactive and fluid.

  • Use of cryoprotectants and cold/heat shock proteins to prevent protein denaturation and maintain structure.

Microbial Presence in Various Environments

• Microbes are Everywhere: Found in marine environments, caves, soil, plants, animals, and the atmosphere.

Marine Environment Insights

• Neritic Zone:

  • Nutrient-rich, mild temperature, and diverse marine life.

• Oceanic Zone:

  • Increasing pressure and presence of chemotrophs.

Ocean Plankton

• Importance:

  • Responsible for 50-80% of Earth's oxygen production.

  • Prochlorococcus: A specific bacterial species generating 20% of Earth’s oxygen.

  • Co-occurrent with Synechococcus, contributing approximately 50% of marine carbon fixation.

• Prochlorococcus: Rapid multiplication and environmental adaptability.

Microbes in the Environment

• Plastic Pollution: Increased since 1950, with toxic effects impacting the microbiome.

  • Microbes as platforms for colonization and carbon sources.

Microbial Biodegradation Processes

• Mechanisms:

  • Biodegradation: Physical or chemical changes to materials (e.g., plastics) by microorganisms.

  • Anaerobic and aerobic processes:

    • Plastics with oxygen yield CO2 + H2O.

    • Plastics without oxygen yield methane + CO2 + H2O.

Microbes in Technology - PCR

• Taq Polymerase: DNA polymerase I from Thermus aquaticus revolutionized molecular biology.

  • Key steps in PCR: Template preparation, primer annealing, cycling conditions (95ºC, 55-60ºC, 72ºC).

• Significant Development: Saiki et al. (1985) published findings in Science.

Restriction Enzymes in Technology

• Definition: Proteins from bacteria that cleave DNA at specific sites.

  • Essential for genetic engineering.

• Nobel Prize Recognition: Arber, Smith, and Nathans for their discovery in 1978.

CRISPR-Cas9 Technology

• Overview: Bacterial and archaeal immune response system used for DNA editing.

  • Components: Cas9 protein, pre-crRNA, tracrRNA.

• Significance: Enables precise targeting of DNA sequences.

  • Nobel Prize awarded to Charpentier and Doudna in 2020.

Vaccines and Microbial Technology

• Recombinant Vaccines: Examples include Hepatitis B and SARS-CoV-2 vaccines produced using yeast.

• ChAdOx1 nCoV-19 vaccine: Uses a replication-deficient adenoviral vector to elicit immune response against COVID-19.

Microbes in Medicine: Cancer Association

• Microbial Links to Cancer:

  • Human Papillomavirus (HPV) linked to cervical cancers.

  • Helicobacter pylori linked to gastric cancer.

  • Schistosoma haematobium associated with bladder cancer.

Microbes as Cancer Therapeutics

• Treatment Options: Various microorganisms used to treat cancers beneficially.

  • Mycobacterium bovis: Superficial bladder cancer therapy.

  • Streptococcus pyogenes: Alternation to lymphangioma surgeries.

  • Clostridium novyi: Investigated for solid tumors.

  • Other examples of potential treatments mentioned.

Antibiotics from Microbes

• Penicillin: First discovered by Alexander Fleming from Penicillium notatum. Key in the development of beta-lactam antibiotics.

  • Broad spectrum against bacteria through cell wall inhibition.

• Nobel Prize Recipients: Florey and Chain recognized for demonstrating penicillin efficacy in humans and industrial application.

• Actinomycetes: Source of various antibiotics, notably discovered by Selman Waksman, including streptomycin in 1943.

Summary of Key Topics

• Environmental impacts of microbes, degradation of plastics, plankton roles, technological applications (PCR, Restriction Enzymes, CRISPR-CAS), medicine impacts (vaccines, cancer therapeutics, antibiotics).