Scope of Microbiology

Week 1 Lecture: Scope of Microbiology

• Germ comes from the Latin "germen," meaning "to sprout or germinate"
• Germ was first used with bacteria in the 19th century to explain rapidly growing, disease-causing cells
• Microbes, also known as microorganisms, are living organisms that are only visible with a microscope
• Microbiology studies microscopic organisms, including bacteria, archaea, viruses, fungi, prions, protozoa, and algae, collectively known as 'microbes'

Development of Microbiology Pioneers

• Anton van Leeuwenhoek (1632-1723) is known as the "Father of Microbiology," "Father of Bacteriology," and "Father of Protozoology."
• Leeuwenhoek created single-lens microscopes by grinding tiny glass lenses and mounting them in metal frames
• In specimens, Leeuwenhoek observed tiny living creatures called "animalcules."
• Louis Pasteur (1822-1985) discovered life forms that can exist without oxygen
• Pasteur introduced "aerobes" (organisms requiring oxygen) and "anaerobes" (organisms not requiring oxygen)
• Pasteur developed pasteurization to kill microbes causing wine spoilage
• Pasteur developed a rabies vaccine for dogs and treated human rabies
• Pasteur discovered alcoholic fermentation, demonstrating that different microbes produce different fermentation products
• Yeasts convert glucose to ethyl alcohol (ethanol) through fermentation
• Acetobacter bacteria convert glucose to acetic acid (vinegar), ruining wine taste
• Joseph Lister (1860s) proposed surgical infection (sepsis) is caused by microorganisms
• Sepsis results from pathogenic microbes or their products in blood or tissues
• Lister devised methods to prevent microbes from entering wounds, known as antiseptic surgery
• Methods included hand washing, sterilizing instruments, and dressing wounds with carbolic acid (phenol)
• Ignaz Philip Semmelweis (1840s) used antiseptic procedures to prevent "childbirth" or puerperal fever, a serious infection contracted during delivery
• Robert Koch (1867) provided evidence that bacteria are disease-causing agents (etiological agents)
• Koch determined Bacillus anthracis causes anthrax in sheep and cattle
• Koch established experimental steps, known as Koch's postulates, to demonstrate a specific type of microorganism causes a specific disease
• Koch proved the anthrax bacillus (B. anthracis) causes anthrax using Koch's postulates
• Koch discovered B. anthracis produces spores, capable of resisting adverse conditions
• Koch developed methods of fixing, staining, and photographing bacteria
• Koch's work on tuberculin, derived from M. tuberculosis, led to a skin test valuable in diagnosing tuberculosis
• Koch discovered the bacterium (M. tuberculosis) that causes tuberculosis and the bacterium (Vibrio cholerae) that causes cholera
• Richard J. Petri developed the Petri dish to grow and manipulate microbial cultures
• Fanny Hesse developed the use of agar as a solidifying agent for microbiological media
• Hans Christian Gram developed the Gram stain technique, separating major groups of disease-causing bacteria
• Edward Jenner (1796) used material from cowpox-infected individuals to immunize against smallpox
• Alexander Fleming (1928) discovered penicillin
• Fleming noticed mold inhibited bacterial growth and isolated the substance
• Microorganisms are diverse, including bacteria, fungi, algae, protozoa, microscopic plants (green algae), and viruses
• A microorganism can only be seen through a microscope
• The two major categories of microbes include:
  • Acellular microbes; infectious particles,
  • Lacking cellular organization, not delimited by cytoplasmic membranes.
• Viruses, viroids, virusoids, and prions are acellular microbes
• Acellular microbes cannot be seen with a light microscope
• Cellular microbes are microorganisms include all bacteria, all arachaea, some algae, all protozoa and some fungi
• Prokaryotes and eukaryotes are distinguished by cellular characteristics
• Prokaryotes have no nucleus; smallest living organisms, size ranging from 0.15 μm (mycoplasmas) to 2.0 μm (many bacteria)
• Some bacteria have a comma shape (vibrio) or a flexible, wavy shape (spirochete)
• Eukaryotes are cells where genomes are not contained within a nucleus, include fungi, protozoa, and simple algae
• Eukaryotic cells are larger and more complex than prokaryotic cells, containing cellular bodies called organelles
• Bacteria are prokaryotic organisms without a nucleus or nuclear membrane
• Bacteria can be rods (bacilli), spheres (cocci), or spirals (spirilla or spirochetes)
• Bacteria reproduce through binary fission, have unique cell wall ingredients, and are found nearly all world's ecosystems
• Bacteria can survive in temperatures ranging from 0° to 100°C and in oxygen-rich or oxygen-depleted environments
• Fungire are eukaryotic microorganisms
• Fungi include multicellular molds and unicellular (single-celled) yeasts
• Yeasts are slightly larger than bacteria and are employed in the production of alcoholic beverages and bread
• Candida albicans is a pathogenic yeast (disease-causing)
• Molds are filamentous, branching fungi that reproduce through spores.
• Fungi prefer acidic surroundings, most can survive at ambient temperature in an oxygen-rich environment
• A common mushroom is a fungus
• Protozoa are unicellular eukaryotic creatures that can be classed according to how they move
• Some protozoa have flagealla whereas others have cilia or pseudopodia
• Some protozoa are unmobile
• Lacking cell walls, protozoa can take on unlimited shapes,
• Malaria, sleeping sickness, dysentery, & toxoplasmosis are caused by different species of protozoa
• Algae refers to plant-like creatures, cells surrounded by cell walls
• Several spcies of single celled algae are essential in microbiology
• Diatoms & dinoflagellates live in oceans, found at the bottom of marine food chains, catch sunlight & convert it to chemical energy
• Viruses are tiny amounts of genetic material (DNA or RNA) encased in a protein shell
• Occasionally, a membranous envelope is also present
• Viruses lack a metabolism, interferring with structures of activities w/ medications is challenging
• Reproduction happens in living cells where the cell's chemical machinery is utilized in order to duplicate viruses
• Often the cells are frequently damaged in this reproduction process
• Bacteriophages are a special type of virus that infects primarily bacteria

Division of Microbiology

• Branches of Microbiology can be classified into Pure and Applied Sciences
• Pure Microbiology
  • Thorough investigation of organisms
  • Microbial cytology - Study of microorganisms microscopic and submicroscopic features
  • Microbial physiology - Study of how biochemistry of a microbial cell works. Includes the study of microbial growth, microbial metabolism, and microbial cell structure
  • Microbial pathogenesis - Study of the process where microorganisms cause a disease
  • Microbial ecology - Relationship between microorganisms and their environment
  • Cellular microbiology - How pathogenic microorganisms interact with host cells in what is turning out to be a complex evolution battle of competing gene products
  • Microbial genetics - How genes are structured and regulated in microbes in relation to their cellular functions. Closely related to the field of molecular biology
  • Microbial evolution - Study of microbial evolution, can be classified into:
    • Microbial systematics - The study of microbial diversity and genetic relationships
    • Microbial taxonomy - Naming and classifying microbes
  • Generation microbiology - Study those microorganisms that have the same characters as their parents
  • Phylogeny - Study of the genetic relationships between different organisms
  • Systems microbiology - Bridge systems biology and microbiology
  • Astro microbiology - Study of microorganisms in outer space
  • Biological agent - Study of microorganisms which are being used in weapon industries
  • Nano microbiology - Study of microscopic organisms on nano level
  • Predictive microbiology - Quantification of relations between controlling factors in foods and responses of pathogenic and spoilage microorganisms using mathematical modeling

Applied Microbiology

• Organisms not examined, rather, applied to a specific process
  • Medical microbiology - Study of pathogenic microbes & role of microbes in human illness
  • Microbial pathogenesis and is related to the study of disease pathology and immunology
    • Covers the study of human microbiota, cancer, and tumor microenvironment.
  • Pharmaceutical microbiology - Study of microorganisms involved in manufacturing antiobiotics, enzymes, Vits, vaccines, etc. Things that cause pharmaceutical contamination and spoil.
  • Industrial microbiology - Explore microbes for use in industrial processes
  • Examples: Industrial fermentation and wastewater treatment. Closely linked to biotechnology industry. Included in this field is brewing
  • Microbial biotechnology - Manipulation of microorganisms at the genetic and molecular level to generate useful products
  • Food microbiology - Studying microorganisms causing food spoilage & foodborne illness. Using microorganisms to produce foods, for example by fermentation.
  • Agricultural microbiology - The study of agriculturally relevant microorganisms
    • Plant microbiology and Plant pathology - Studying interactions between microorganisms, plants, and plant pathogens
    • Soil microbiology - Studying microorganisms found in the soil
  • Veterinary microbiology - Studying the role of microbes in veterinary medicine or animal taxonomy
  • Environmental microbiology - Studying the function and diversity of microbes in their natural environments.
    • Involves the characterization of key bacterial habitats such as the rhizosphere and phyllosphere, soil & open oceans or extreme environments(extremophiles).
      • Microbial ecology
      • Microbially mediated nutrient cycling
      • Geomicrobiology
      • Microbial diversity
      • Bioremediation - To clean the environment
  • Water microbiology (or aquatic microbiology) - Study those microorganisms that are found in water
  • Aeromicrobiology (or air microbiology) - Study airborne microorganisms
  • Biotechnology - Recombinant DNA technology or genetic engineering

Taxonomy-Based Microbiology Types

• Bacteriology - Study of bacteria
• Immunology - Study of the immune system; relations between pathogens
• Mycology - Study of fungi
• Nematology - Study of nematodes
• Parasitology - Study of parasites
• Phycology - Study of algae
• Protozoology - Study of protozoa, single-celled organisms (e.g. amoeba)
• Virology - Study of viruses

Genetic Engineering and Biological Warefare

• Engineered microorganisms are used to make hormones, antibiotics, vaccines & other products, with new genes inserted into plants and animals
• Biotechnology contains commercial applications that include the synthesis of different things like acetone, drugs, different acids & enzymes
• Biological warfare (aka germ warfare) is the use of biological toxins or infectious agents in order to kill someone & cause harm to others
• Microbial Ecology's purpose is recycling vital elements, the study of the relationship between microorganisms/ the environment
• It's essential in many cases, such as producing O2 by photosynthesis, decomposition
• A saprophyte is something that lives on dead decay
• Medical microbiology important to detection, diagnosis and treatment etc

Week 2 Lecture: Morphology and growth requirement

• Growth curve refers to the phases of growth of the bacterial population
• Bacteria are metabolically active single-celled prokaryotic structures that divide by binary fission, where some have an important role in disease
• Sizes, shapes, and arrangement can be easily viewed with the use of compound light microscope
• Size of spheres: Ranges ~0.2 to 10.0 um long, more for filamentous
• Average: Coccus (1 um), bacillus ( 1 um X 3 um), 0.2 - 5 micrometers
  • Mycoplasma, rods similar to yeast & human blood cells
• Reproduction happens by binary fission, one cell splits in half to become two daughter cells
• Split time = Generation Time
• Sphere, rod, spiral - basic bacterial shapes
• Following division the arrangement is the following...

Appendaged Bacteria Types

• Produce distinct structure/fimbriae, may be virulent eg. Neisseria Gonorrheae
• Pleomorphic = no defined form, alter shape, definite form eg. Mycoplasma
• Filamentous = Filament shape, long and thin eg. Actinomycetes
• Club - side to side ex. Corynebacterium
• Box Shaped /Rectangular = Stalk on 1 side
  • Stella Humosa
  • Classification Bacteria Gram staining
  • Gram positive or negative Some specific example. bacterial capsule/flagella with different identification methods like call Wall ex

Envelopes

• Glycocalyx Capsule function protects, the cells are outside where they attach

• Cell Wall functions provide what is needed in a cell & is made entirely of that cell from myoplasma

• Murein represents a type of bacterial skeleton and is a sacculus-like structure that surrounds it

• gram positive bacteria

• teichoic acid

• Some bacteria can live without teichoic acid

• Gram Negative bacteria

  • O antigen Outer membrane - with LPS
  • Inner proteins
  • All bacteria contains pepto-glycans

Bacteria with projecting structures

• Flagella: thin appendage ext.

• From cytoplasm of cell

• Function in motility

• Axial / Endoflagella

  • Bundle motifs

This lesson covers the scope of microbiology, including the definition of microbes and the history of the field. It highlights key figures like Anton van Leeuwenhoek and Louis Pasteur and their contributions to understanding microorganisms.