Microbial Nutrition

WHAT IS THE DIFFERENCE BETWEEN MICROORGANISMS AND MICROBES?

Definitions

• Microorganism

  • Refers to any microscopic living organism, which includes:

  • Bacteria

  • Viruses

  • Fungi

  • Protozoa

  • Describes tiny life forms that cannot be seen with the naked eye and require a microscope for observation.

  • They can be found in various environments such as soil, water, and air.

• Microbe

  • Refers to a microscopic organism, covering:

    • Bacteria

    • Viruses

    • Some fungi

  • Describes organisms that are too small to be seen without a microscope.

  • Often associated with tiny life forms that can cause diseases or infections.

LIST OF SIMILARITIES

• Both terms reference microscopic organisms.

• Both describe life forms that cannot be seen with the naked eye.

• Both terms include bacteria and viruses.

WHAT IS THE DIFFERENCE?

• Scope:

  • Microorganism is a broader term than microbe, which refers to a limited range of microorganisms.

• Connotation:

  • Microorganism is neutral; microbe may have negative associations due to its link with disease-causing organisms.

• Usage:

  • Microorganism is often used in scientific and academic contexts; microbe appears more frequently in everyday language.

• Specificity:

  • Microbe usually refers specifically to harmful or pathogenic microorganisms.

  • Microorganism can refer to any microscopic living organism.

MEET YOUR MICROBES!

Microbiome and its Functions

• Nose:

  • Mucus production

  • Antimicrobial chemicals

• Mouth:

  • Assists digestion

  • Environment wards off pathogens

• Lungs:

  • Lubricate pulmonary tissues

• Stomach:

  • Prevents gastric complications

  • Digests complex carbohydrates

• Colon:

  • Digestion of complex carbohydrates

• Sexual Organs:

  • Maintain pH levels

  • Hydrogen peroxide (H2O2) production to kill microbes

• Skin:

  • Fortifies the immune system

  • Scent production

MICROBIAL NUTRITION

Goals and Objectives

• Understand the nutritional requirements of different types of microorganisms.

• After this lecture, students should be able to:

  • Explain the nutritional requirements of microorganisms.

  • Define macronutrients, micronutrients, and growth factors.

  • Explain the classification of microorganisms based on the carbon and energy sources they utilize.

  • Explain differences between active and passive transport in cell membranes.

  • Describe the basic types of active and passive transport across the cell membrane.

NUTRITION AND NUTRIENTS

• Nutrition:

  • The process by which living organisms acquire chemical substances (nutrients) from their environment and utilize them for metabolism and growth.

• Essential Nutrients:

  • Substances that must be provided to an organism for survival.

  • Essential for all microorganisms: CHONPS

  • Carbon

  • Hydrogen

  • Oxygen

  • Nitrogen

  • Phosphorus

  • Sulfur

• Microorganisms may need additional essential nutrients.

• Macronutrients:

  • Required in relatively large quantities, specifically: C, H, O

• Micronutrients: (trace elements)

  • Present in small amounts (e.g., Ni, Zn); generally involved in enzyme functions.

• Nutritional analysis:

  • Can be conducted by examining the chemical composition of microorganisms.

• Growth Factors:

  • Organic compounds that an organism cannot synthesize and must acquire as nutrients (e.g., amino acids, nitrogenous bases, vitamins).

NUTRITIONAL TYPES

Based on Carbon Source

• Autotrophs:

  • Organisms capable of using carbon from inorganic compounds (CO2) to synthesize organic compounds.

• Heterotrophs:

  • Organisms that obtain carbon from organic compounds generated by autotrophs.

Based on Energy Source

• Phototrophs:

  • Obtain energy from sunlight via photosynthesis.

• Chemotrophs:

  • Derive energy from chemical compounds.

AUTOTROPHIC MICROORGANISMS

• Photoautotrophs:

  • Engage in photosynthesis (e.g., algae and photosynthetic bacteria).

  • Utilize inorganic compounds as a carbon source and sunlight as energy to produce organic compounds (known as primary producers).

• Chemoautotrophs:

  • Use inorganic compounds as a carbon source and chemical compounds for energy.

• Chemoorganic Autotrophs:

  • Use inorganic compounds for carbon but organic compounds for energy (includes some archaea, bacteria, and yeasts).

• Lithoautotrophs:

  • Utilize inorganic compounds for both carbon and energy sources (e.g., iron bacteria, methanogens).

  • Formula: ext{Hydrogen} + ext{Carbon Dioxide}
    ightarrow ext{Methane} + ext{Water}

HETEROTROPHIC MICROORGANISMS

• Heterotrophs:

  • Primarily chemoheterotrophs, which obtain both carbon and energy from organic compounds.

• Saprobes:

  • Free-living organisms that derive organic compounds from dead organisms.

• Parasites:

  • Extract nutrients from living organisms' cells or tissues (considered pathogens).

• Photoheterotrophs:

  • Acquire energy from sunlight but carbon from organic compounds (includes certain bacteria).

DIFFUSION AND OSMOSIS

Concepts

• Diffusion:

  • Movement of atoms or molecules from an area of higher density to an area of lower density.

• Osmosis:

  • The diffusion of water through a selectively permeable membrane.

• Osmotic Pressure:

  • The pressure required to stop the osmotic flow of water across a semipermeable membrane.

• Tonicity Types:

  • Hypertonic: Higher concentration of solute outside the cell than inside, causing cell shrinkage.

  • Isotonic: Equal concentration of solute inside and outside of the cell, maintaining cell size.

  • Hypotonic: Lower concentration of solute outside the cell than inside, leading to cell swelling and potentially lysis.

PASSIVE TRANSPORT

• Passive Transport:

  • Movement of molecules that does not require energy; molecules move down their concentration gradient.

• Types of Passive Transport:

  • Simple Diffusion:

  • Involves small and hydrophobic molecules passing through a cell membrane.

  • Facilitated Diffusion:

  • Requires transmembrane proteins to allow specific molecules to pass through the cell membrane.

ACTIVE TRANSPORT

• Active Transport:

  • Movement of molecules against their concentration gradient; requires energy (ATP).

• Mechanisms:

  • Carrier-mediated Active Transport:

  • Specific carrier proteins that transport ions or molecules across membranes.

  • Pumps:

  • Proteins that move ions across membranes (e.g., sodium-potassium pump).

  • Group Translocation:

  • Transporter protein acts as an enzyme that alters the substance into a metabolically useful form.

  • Endocytosis (Bulk Transport):

  • Engulfing substances into the cell.

    • Phagocytosis:

    • Engulfs large solid particles or cells.

    • Pinocytosis:

    • Engulfs liquids.