Microbial: Bacterial and Archaeal Traits

• Microbial pertains to microorganisms, which are microscopic organisms like bacteria, archaea, fungi, protists, and viruses.

Bacterial Characteristics

• Bacteria are single-celled prokaryotic organisms lacking a nucleus and other membrane-bound organelles.
• Their cell wall usually consists of peptidoglycan.
• Reproduction typically occurs through binary fission, a form of asexual reproduction.
• Bacteria come in diverse shapes, including cocci (spherical), bacilli (rod-shaped), and spirilla (spiral).
• Many bacteria use flagella for movement.
• Bacteria are vital in nutrient cycling, decomposition, and symbiotic relationships.
• Some bacteria are pathogenic, causing diseases in humans, animals, and plants.

Archaeal Traits

• Archaea are prokaryotic microorganisms that often live in extreme environments like hot springs and salt lakes.
• Their cell walls don't have peptidoglycan, and their membrane lipids differ from bacteria and eukaryotes.
• Genetically, archaea are distinct from bacteria and eukaryotes.
• They participate in biogeochemical cycles, including methanogenesis.
• Some archaea are extremophiles, thriving in high temperatures, salinity, or acidity.
• No archaea are known to be pathogenic.

Fungal Attributes

• Fungi are eukaryotic organisms with cells containing a nucleus and other organelles.
• Fungi can be unicellular (yeasts) or multicellular (molds and mushrooms).
• Fungal cell walls are made of chitin.
• Fungi are heterotrophic, getting nutrients from organic matter.
• They reproduce sexually and asexually through spores.
• Fungi function as decomposers, pathogens, and in symbiotic relationships like mycorrhizae.
• Certain fungi are used in food production (e.g., yeast in bread) and medicine (e.g., penicillin).

Protistan Features

• Protists are a diverse group of eukaryotic microorganisms that are not fungi, animals, or plants.
• They can be unicellular or multicellular.
• Protists use a wide range of nutritional strategies, including autotrophy, heterotrophy, and mixotrophy.
• They reproduce sexually and asexually.
• Algae, protozoa, and slime molds are types of protists.
• Certain protists are key primary producers in aquatic ecosystems.
• Others are human pathogens, causing diseases like malaria and giardiasis.

Viral Properties

• Viruses are acellular and not considered living organisms.
• They consist of genetic material (DNA or RNA) inside a protein coat called a capsid.
• Viruses need a host cell to replicate because they lack the machinery for independent reproduction.
• They infect diverse organisms, including bacteria, archaea, fungi, protists, plants, and animals.
• Viral infections can cause various diseases.
• Bacteriophages are viruses infecting bacteria.

Microbial Ecology

• Microbial ecology studies how microorganisms interact with each other and their environment.
• Microorganisms live in diverse habitats, including soil, water, air, and plant and animal bodies.
• They form complex communities and participate in ecological processes.
• Microbes are essential for nutrient cycling, decomposition, and bioremediation.
• Microbial interactions may be competitive, cooperative, or symbiotic.
• The human microbiome includes microorganisms living in and on the human body.

Microbial Genetics

• Microbial genetics studies the inheritance and variation of microorganisms.
• Bacteria and archaea have a single circular chromosome.
• Microorganisms exchange genetic material through horizontal gene transfer mechanisms like conjugation, transduction, and transformation.
• Genetic mutations can result in antibiotic resistance and other adaptations.
• Microbial genetics is applied in biotechnology, medicine, and agriculture.

Microbial Metabolism

• Microbial metabolism includes the chemical processes that microorganisms use for energy and nutrients.
• Microbes have diverse metabolic pathways, including aerobic respiration, anaerobic respiration, and fermentation.
• Some microbes are autotrophs, using inorganic compounds or light as energy sources.
• Others are heterotrophs, getting energy from organic compounds.
• Microbial metabolism is critical in biogeochemical cycles like the carbon and nitrogen cycles.

Microbial Pathogenesis

• Microbial pathogenesis studies how microorganisms cause disease.
• Pathogens may produce toxins, invade tissues, and evade host defenses.
• Virulence factors enhance a pathogen's ability to cause disease.
• The immune system defends against microbial infections through innate and adaptive immunity.
• Antibiotics and other antimicrobial drugs treat bacterial infections.
• Vaccines can protect against viral and bacterial diseases.