MCB 11 - 1st Long Quiz

microbiology

Study of single-celled organisms that contain a nucleic acid genome and is able to replicate

Paramecium epulopiscium

Eukaryote that lives in the gut of Acantharus lineatus, sturgeonfish

Thiomargarita magnifica

Largest bacterium, 9000 micrometers

Miasma

Attributed disease to bad air

Thiomargarita namibiensis

Former largest bacterium, 1800 micrometers

Hippocrates

Father of western medicine

Thucydides

Father of scientific history

Marcus Terentius Varro

Proposed that things we can’t see (microorganisms) can cause disease

Zaccharias Janssen

Invented first compound microscope

Athanasius Kirche

First to observe microorganisms

Antonie van Leeuwenhoek

“Wee animalcules”

Robert Hooke

Made first recorded microscopic observation

Spontaneous Generation

Life emerges from non-living matter; vital force required

Biogenesis

“Life begets life”

Francesco Redi

Founder of experimental biology

John Needham

experimented on mutton broth in flash, boiled, sealed

Lazzaro Spallanzani

Redid Needham’s experiment with longer boiling time and proper control

Franz Schultze

Passed air through strong acids

Theodor Schwann

Passed air through red hot tubes; no microbial growth

Louis Pasteur

Swan-neck flasks, proved that life did not arise from non-life, founded pasteurization

John Tyndall

Demonstrated that dust carries microorganisms, provided evidence for existence of exceptionally heat-resistant forms of bacteria

Germ Theory of Disease

Diseases are caused by specific agents: germs

Georg Schröder & Theodor von Dusch

Filtered air through sterile cotton wool; no microbial growth

Girolamo Fracastoro

Disease caused by invisible living creatures

Agostino Bassi

Showed that a disease of silkworms was caused by a fungus

Miles Joseph Berkeley

Proved that the potato blight of Ireland was caused by a fungus

Heinrich de Bary

Showed that smut and fungi was caused by cereal crop diseases

Ignaz Philipp Semmelweis

Championed hand-washing with calcium hypochlorite

Joseph Lister

Father of antiseptic surgery; perfected optical microscope

Robert Koch

Main founder of modern microbiology

Variolation

Practice of infecting people with low doses of smallpox

Edward Jenner

Used a vaccination procedure to protect individuals from smallpox

Pasteur and co-workers

Developed vaccines for chicken colers and anthrax rabies

Attenuation

Growing pathogen in an unnatural host that weakens it

Charles Chamberland

Develeoped porcelain bacterial filter

Martinus Beijenrick

one of the founder of virology; discovered nitrogen fixing; developed enrichment cultures and selective medium

Paul Ehrlich

Developed SALVARSAN (orgabic arsenal to treat syphilis)

Alexander Fleming

Developed miracle drug/penicillin

Edward Buchner

Fermentation could occur in yeast extracts free of cells

Ferdinand Cohn

Existence of heat-resistant bacterial endospores

Sergei Winogradsky

Discovered litotrophy and chemoautotrophy

Galieo Galilei

Used a compound microscope to examine insect parts

Light Microscope

Light waves and mirror

Simple Light Microscope

Short focal length, 1 lens, magnification: 300x

Compound Light Microscope

2 sets of lenses, magnification: 3000x

Bright Field Light Microscope

objects under study are darker against a brighter background

Dark Field Light Microscope

For specimens that cannot be stained by standard methods

Phase Contrast Light Microscope

Uses refraction & interference caused by structures in a specimen

Differential Interference Contrast Light Microscope

Variations in refractive indices, three-dimensional

Fluorescence

Detection of immunological reactions

Confocal Light Microscope

Useful for thick specimens like biofilms

Two-Photon Light Microscope

Useful for examining living cells with intact tissues

Electron Microscope

Electron beams as energy source

Scanning Electron Microscope

Utilizes an electron beam but image is formed from secondary electrons

Transmission Electron Micsroscope

Utilizes an electron beam directed at the specimen with the use or electromagnets

Scanning Probe Microscope

Allows to ciew images at an atomic level

Scanning Tunneling Microscope

Uses very sharp probes that are passed over the surface of the specimen and interact with it directly

Atomic Force Microscope

Establishes a constant current and measures variations in the height of the probe tip as it passes over the specimen

Stage

Where specimen on a glasss slide in clipped into place

X-y mechanical stage knobs

Positions specimen on a slide

Coarse focusing knob

For large scale movements: 4x & 10x objective lenses

Fine focusing knob

For small scale movements: 40x & 100x objective lenses

Illuminator

A high intensity bulb below the stage

Condenser Lens

Focuses all of the light rays on the specimen to maximize illumination

Diaphragm

If less than maximal light levels are needed, amount of light can be adjusted here by opening and closing it between condenser and specimen

Rheostat

Brightness adjustor; a dimmer that controls intensity of the illuminator

Living or Natural State Preparations

Observation of unaltered characteristics

Stained Preparations

Provides contrast, preserved slides, specimens are killes

Steps in Staining

1. Smear Preparation

2. Fixation

3. Staining

Dye/stains

Organic compound carrying chromophoric ions

Simple Staining

One dye only

Positive/Direct Staining

Basic dyes, same color as dye

Negative/Indirect Staining

Acidic dyes, cells colorless or luminous

Differential Staining

2 or more dyes/reagents

Gram Staining

Differentiating bacteria by the chemical and physical properties of their cells walls

Crystal Violet

Primary stain

Iodine

Mordant

Alcohol

Decolorizer

Safranin

Counterstain

Acid-Fast Staining

Used for diagnosing tuberculosis

Structural Staining

Helps in visualization of bacterial structure

Types of Structural Staining

Capsules, Endospores, Flagella, Storage Granules

Pure Culture

Contains a singles species of microorganisms

Nutrients

extracellular substances which provide cell with materials for protoplasm building and energy generation

Essential Nutrients

C, H, O, N, P, S

Culture Medium

Any nutrient material for growth and cultivation of microorganism in the lab

Cultivation

Increasing population of microorganism by providing nutritional and physical requirements

Types of Culture Medium: Physical State

Liquid, semi-solid, solid

Types of Culture Medium: Chemical Composition

Synthetic, complex

Types of Culture Medium: Function

General purpose, enrichment, differential, selective, assay

Steps in preparing pure cultures

1. Isolation

2. Transfer desired colony to desired stab or slant

3. Verify purity

4. Make stock cultures

Culture Preservation

To retain viability or stock culture for a long period of time while maintaining its purity

Why control growth of microorganisms?

Prevent spoilage, infection and contamination

Sterilization

Complete destruction of all viable organisms in an object or habitat

Disinfection

Killing, inhibition or removal of pathogenic microorganisms

Sanitization

Reduction of microbial population to levels considered safe by public health standards

Antisepsis

Prevention of infections in living tissues using chemicals

Antiseptics

Selectively goes against microorganisms and does not cause tissue damage

Degerming

Mechanical removal and use of mild chemicals on tissues or skin (ex. Handwashing)

Antimicrobial agents

Chemicals that kill or prevent microbial growth