Unit 1- Microbiology

Define Microbes or Microorganisms

Minute living things that are usually unable to viewed with the naked eye

Examples of microbes

Bacteria, fungi, protozoa, algae, viruses

Germ refers to

a rapidly growing cell

What can microbes do? (4)

• Decompose organic waste

• Producers in the ecosystem by photosynthesis

• Produce industrial chemicals such as ethyl alcohol and acetone

• Produce fermented foods

Knowledge of microbes allows humans to: (3)

• Prevent food spoilage

• Prevent disease occurrence

• Aseptic techniques

Robert Hooke

Reported that living things were composed of little boxes of cells

Anton von Leeuwenhoek- Father of Microbiology

using his improved microscope lens observed live microorganisms

Francesco Redi

Performed experiment to disprove spontaneous generation

Spontageous generation

Living organisms arise from nonliving matter

Biogensis

Living organisms arise from preexisting life

Louis Pasteur

Discredited the idea of spontaneous generation, showed that microbes are responsible for fermentation

Proposed the germ theory

Proved that yeasts were responsible for fermentation

Pasteurization

Application of a high heat for a short time

Epidemiology

The study of the source, cause, and mode of transmission of disease

Ignaz Semmelweis

Advocated handwashing with lime solutions to prevent transmission of child bed fever

John Snow

determined the cause of cholera transmission

Edward Jenner

inoculated a person with cowpox virus, creating immunity through vaccination

Joseph Lister

Used a chemical disinfectant to prevent surgical wound infections

Koch’s postulates: used to prove that a specific microbe causes a specific disease (4)

1. same microorganisms are present in every case of the disease

2. Microorganisms are isolated from the tissues of a dead animal, pure culture is prepared

3. Microorganisms from the pure culture are inoculated into a healthy animal and disease is reproduced

4. Identical microorganisms are isolated and recultivated from the tissue specimens of the experimental animal

There are 2 domains of prokaryotes

Bacteria and archaea

Bacteriology

study of bacteria

Virology

study of viruses

Mycology

Study of fungi

Parasitology

study of protozoa and parasitic worms

Genomics

study of organism’s genes

Eukaryotic

(plant,animal,fungi,protist) cells contain a membrane-bound nucleus

Prokaryotic

(bacteria, archaea) cells lack a membrane-bound nucleus

Antibiotics

chemicals produced by bacteria and fungi that inhibit or kill microbes

Antimicrobial

any drug synthetic or natural, that inhibits or kills microbes

Chemotherapeutic agents

Used to treat infectious disease can be synthetic drugs or antibiotics

Paul Ehrlich

developed a synthetic arsenic drug, salvarsan, to treat syphilis

Alexander Fleming

Discovered the first antibiotic- Penicillium

Phylogeny

identifies evolutionary relationships between organisms

Bioremediation

use of microorganisms to remove or decontaminate toxic materials in the environment

Biofilms

complex community of microbes

Isotopes

atoms of the same element that have a different number of neutrons

Hydrogen bonding

electrostatic attraction between a partially negative atom and a partially positive atom

Hydrolysis

Break larger compounds into smaller ones

Dehydration synthesis

add smaller reactants together to form a larger product

Functional groups

groups of atoms projecting from biological molecules

RNA

single-stranded molecule that copies gene information for use in protein synthesis

Primary structure

sequence of amino acids in the polypeptide

Secondary structure

Regions form an alpha helix, pleated sheet, or random coil

Tertiary structure

part of the polypeptide folds back on itself R groups interact

Quaternary structure

occurs when 2 or more polypeptides join to form the protein

Characteristics of Fungi (4)

• Lacks chlorophyll

• Cell walls contain chitin

• Fungi are not multicellular

• Heterotrophic

Difference between Fungi and Bacteria

• Fungi like pH 5-6

• Fungi grow best at ~23C

• Fungi are more resistant to osmotic pressure

• Fungi require less water

Fungi Growth Influences

• Take up nutrients through absorption

• Most molds are aerobic (utilizes oxygen and detoxify)

• Most yeasts are facultative anaerobes (utilizes oxygen but possible without)

• Growth at room temperature ~23C

• Thrive at slightly acidic pH

Axsexual Structures

Blastospore

Conidia

Arthrospore

Types of Hyphae

Mycelium - mass of hyphae

Stolon - surface hyphae

Rhizoid - anchoring hyphae

Sporangiophore - special hypha that bears sporangia

Conidiophore - special hypha that bears conidia

Fungi Classification (Lack Sexual Cycle) 5

• Chytridiomycota, flagellated reproductive cells

• Glomeromycota, group of mycorrhizae

• Zygomycota, mold on produce

• Ascomycota, 75% of known fungi

• Basidiomycota, mushrooms and puffballs

Gernereal Asexual Sequence

• “spore”: germinates into hyphae, rhizoids and stolons

• Sporangiophore: special hyphae that bears sporangia

• Sporangia: produces identical spores by mitosis

General Sexual Reproduction Sequence

• “spore”

• 2 different mating types from gametangia

• gametangia (n): 2 fuse to form a zygospore

• zygospore (2n): produces sporangium via meiosis

• sporangia (n): contains genetically different spores

Mycorrhizae

Associations between fungi and the roots of plants

Lichens

Symbiotic relationship between a fungus and either an alga or cyanobacterium

Pathogenic fungi

Can infect plants and humans

Toxic fungi

Some fungi can produce mycotoxins

Mycetism

Mushroom poisoning, mushrooms produce mycotoxins

Dermatophytosis

Infection of the body surface by contact with domestic animals and fomites

Oral candidiasis (thrush)

involves white curd-like growth on the mucous membranes of the mouth

Cryptococcosis

Occures in immunocompromised individuals (C. neoformans) found in urban soil and pigeon droppings

Histoplasmosis

Produce a systemic disease, found in soil, chicken coops and bat caves

Blastomycosis

Inhalation of soil and bird droppings causing pneumonia and disseminate other organs

Coccidiodomycosis

Lethal Infection from inhalation of spores resulting in infection to tissues in spinal cord

Aspergillosis

conidia enter the body and grow as mycelium

Prokaryote/Eukaryote Similarities

• DNA controls structure and function

• Response to stimuli

• Reproduce offspring

• Adapt across generations

• Interaction with environment

• Biochemical reactions used for growth and energy conversions

Multicellular development

Cells cooperate with each other as seen in biofilms, bacterial communal associations

Chemical quorum sensing

Initial Attachment

Irreversible Attachment

Maturation I

Maturation II

Dispersion

Prokaryotes and Eukaryotes: Structural Distinctions

- Eukaryotes have membrane-enclosed organelles,

some bacteria have microcompartments

– Protein/lipid transport in eukaryotes is carried out by

the endoplasmic reticulum and Golgi apparatus

– Mitochondria perform cellular respiration in

eukaryotes, while prokaryotes use the cytoplasm and

cell membrane

– Both eukaryotes and prokaryotes can perform

photosynthesis

The eukaryotic cytoskeleton gives the cell

structure and transports materials within the

cell.

– Both eukaryotes and prokaryotes use flagella

for motility, though the flagella differ structurally

and functionally in the two groups.

– Many prokaryotes and eukaryotes have a cell

wall to help maintain water balance by osmosis.

Taxonomy

Science of classification, involving arranging related organisms into logical categories

Carolus Linnaeus

establishing a uniform system for naming ogranisms

Nomenclature

Scientific Names to Organisms; 2 words (genus and specific epithet)

Ernst H. Haeckel

coined the term “protist” for all microoganisms

Robert H. Whittaker and Lynn Margulis