The Microbial Planet Quiz

The Microbial Planet

• Earth is approximately 4.6 billion years old
• Single-celled microorganisms were the first organisms on Earth, appearing approximately 3.7 billion years ago, far before plants and animals.
• Microorganisms can be documented throughout 80% of Earth's history.
• Louis Pasteur stated, "The role of the infinitely small in nature is infinitely large."

Lecture Topics

• Meet the Microbes
• The Microbial Planet (covering the history of human-microbe interactions)
• Medical Microbiology
• Prokaryotic genetics
• Microbial molecular diagnostics
• Microbiomes
• Environmental Microbiology
• Microbes and Food Production
• Food Preservation Methods
• Marine Microbiology
• Tutorials/Practicals

Lecturers

• Dr Merve Suzan
• Zeden
• Prof Vince O'Flaherty
• Prof Gerard Wall
• Dr Kate Reddington
• A. Prof Florence Abram
• Dr Gavin Collins
• Dr Alma Siggins
• Dr Katrina Lacey

O₂ Atmosphere

• Evidence of early microorganisms is recorded in the fossil record of stromatolites.
• Stromatolites are organo-sedimentary structures formed by sediment trapping, binding or precipitation due to the growth and metabolic activity of microorganisms, mainly cyanobacteria (photosynthetic bacteria).
• Stromatolites developed in shallow water where light and CO₂ supported photosynthesis.
• Photosynthetic activity on ancient Earth consumed atmospheric carbon dioxide (CO2) and enriched the atmosphere with oxygen (O2), paving the way for plant and animal life.

Historical 5 Kingdoms of Life

• The original five-kingdom classification of organisms was based on morphology and nutrition.
• This method proved to be incorrect
• Prokaryotes were grouped into a single kingdom (Monera), while four other eukaryotic kingdoms (Protista, Plantae, Fungi, and Animalia) were established.

This Classification is Incorrect

• Bacterial morphology does not accurately reflect their taxonomy.

Classification Based on Analysis of Gene or Amino Acid Sequences

• Classification is based on the analysis of gene or amino acid sequences.
• By comparing similar gene sequences in various organisms, evolutionary relatedness can be determined.
• This method is termed phylogenetics.
• Carl Woese used ribosomal RNA gene analysis to establish the universal tree of life.

Three Domains of Life

• All living organisms fall into one of three domains: bacteria, archaea, or eukaryotes.
• Bacteria and archaea are distinct domains.
• The eukaryotes domain encompasses all eukaryotic cells, including algae, slime molds, fungi, plants, animals, and humans.
• Extraordinary diversity is evident within the prokaryote domains.
• The vast majority of living organisms are prokaryotes (bacteria and archaea).

How Many?

• Estimated total number of prokaryotes: 4 - 6 x 10^30.
• This is a massive number, far exceeding the number of stars in the universe or people on Earth (approximately 6 billion).

Macroscopic Clues to Microorganism Abundance

• Nutrient-rich waters supporting harmful algal blooms (HABs), such as E. huxleyi blooms, can indicate significant microorganism presence.
• Biofilms inside industrial pipes are another macroscopic indication of microbial abundance.

Impact of Microbiology

• Microbiology impacts various aspects, including Health, Food, Environment, Energy, Biotechnology, Agriculture, and Climate & Global Climate Change.

Microorganisms: Friend or Foe

• The majority of microorganisms are friendly, but a small fraction causes disease.
• Microorganisms cause diseases such as; Scalded Skin Syndrome, Pneumonia, Nephritis etc.

Health Impacts

• A small number of microorganisms cause illness in humans and animals.
• Microbiology studies have contributed to successful disease control measures worldwide, such as the development of antibiotics, vaccines, and improved sanitation.

Death Rates (USA 1990-2000)

• Comparing death rates in the USA from 1900 to 2000, there is a significant decrease in mortality from microbial diseases but no significant decline in overall non-microbial deaths.

Methicillin-Resistant Staphylococcus aureus (MRSA)

• MRSA is a strain of Staphylococcus aureus that is highly resistant to multiple antibiotics.
• MRSA can cause skin and soft tissue infections, bacteremia, infections in various organs, leading to various health issues.

Cholera

• Cholera is a waterborne illness caused by the bacterium Vibrio cholera, transmitted via contaminated water or food.
• Common symptoms include watery diarrhea, nausea/vomiting, dehydration, low blood pressure, rapid heart rate, persistent vomiting, and muscle cramps.

Microbiology & Food

• Food spoilage and illness are caused by microorganisms such as E. coli 0157:H7.

Food Preservation

• Preservation techniques, such as canning, freezing, freeze-drying, pasteurization, pickling, and radiation/chemicals, can extend the shelf life of food products.
• Food additives (example: monosodium glutamate, citric acid, yeast) are sometimes used in the preservation process.

Food Production

• Microorganisms, such as yeasts and lactic acid bacteria, play crucial roles in producing various food products, such as beer, wine, bread, yogurt, cheese, sour cream, and buttermilk.

Microbiology and Agriculture

• Microorganisms play vital roles in various aspects of agricultural practice, including soil health and fertility, animal husbandry, and disease prevention.

Nitrogen (N2) Fixation

• Soil microorganisms mineralize organic matter, cycling essential nutrients (e.g., nitrogen, sulfur).
• Legumes form symbiotic relationships with certain bacteria, enabling nitrogen fixation (atmospheric N2 conversion into usable forms).

Ruminants and Cellulolytic Microorganisms

• Ruminants (e.g., cows, sheep, goats) have a rumen that supports microorganisms for cellulose digestion.

Agriculture: Foe Aspect

• Plant and livestock pathogens, such as Mycobacterium (bovine tuberculosis), foot-and-mouth disease virus, and Staphylococcus aureus (dairy cattle mastitis) have an impact on agricultural production.

Energy and Environment: Biofuels

• Various microorganisms produce biofuels such as methane, bioethanol, biomethanol, biobutanol, biomethane, biohydrogen, and biodiesel for energy generation. These biofuels offer an alternative to traditional fossil fuels.

Bioremediation

• Natural microbial communities have the ability to break down various environmental contaminants.
• Bioremediation involves the use of microorganisms to clean or repair contaminated environments.
• Bioremediation strategies such as bioaugmentation, biostimulation, and bioattenuation can be actively used to assist in the process.

Microorganisms: Engines of the Earth's Biosphere

• Microorganisms drive essential biological activities such as primary productivity, nutrient cycling etc.

Microorganisms : Cycle Essential Nutrients

• Microorganisms play an essential role in the cycling of various vital elements, such as carbon (C), nitrogen (N), phosphorus (P), sulfur (S), and oxygen (O).

Microorganisms and Biotechnology

• Microorganisms are used in various biotechnology applications, such as producing enzymes, pharmaceuticals, GMOs, biosensors, novel chemical products, and gene therapy.

Emerging Biotechnology: Synthetic Biology

• Synthetic biology aims to combine engineering approaches with microbiology to design and construct microorganisms for specific functions (e.g., biofuel production).

Plastic-Eating Bacteria

• Researchers are engineering bacteria to degrade plastic waste.

Test your knowledge on the history and significance of microorganisms on Earth. This quiz covers topics such as microbial evolution, human-microbe interactions, and the role of microbes in various environments. Dive into the fascinating world of microbes and their impact on our planet!