MICRO 442- Chapter 1: Observing Microorganisms and Microbial Structures

What is microbiology?

microbiology is the study of small organisms, microbes, microorganisms or germs

Virology

the study of viruses

Bacteriology

the study of bacteria

Parasitology

the study of parasites/protozoa

Mycology

the study of fungi/mold/yeasts

Immunology

the study of the immune system

Pathology

the study of disease

Microbiology is a broad term that consist of:

immunology, pathology, toxicology microbiology, environmental microbiology, food microbiology, wine microbiology, medical microbiology

Medical microbiology

the study of the relationship between disease and microorganisms

The scientific method

a strategy that is used to answer a question or solve a problem

Steps of the scientific method

Observation, hypothesis, performing an experiment, data analysis, and conclusion

The scientific method is a ______ process

dynamic

what is the original observation that led to the development of microbiology?

disease

Who developed the theory of Spontaneous Generation or Abiogenesis?

John Needham

What is the theory of Spontaneous Generation or Abiogenesis argue?

life comes from no where

describe the John Needham Experiment (1748)

he placed chicken broth with microbial growth in a jar with an open top, over a burner to let it boil; the broth then appeared clear of life after boiling; days later the broth had microbes in it

Why was John Needham Experiment wrong?

he left the jar uncovered which allowed for airborne microorganisms to enter the jar

Who disapproved John Needham’s theory of spontaneous generation?

Francesco Redi and Louis Pasteur

Who was the first scientists to challenge spontaneous generation?

Francesco Redi

What was Francesco Redi’s experiment

Fly/maggot experiment proved spontaneous generation was not correct

How did the fly/maggot experiment work?

first, two jars with meat in them were sealed with a cork lid, no traces of flies or maggots were found; then, two other jars with meet in them and a cheese coth on top attracted flies to the top and as they left, maggots were left on the cheese cloth; Finally, two more jars with meat in them were left open allowing for flies to reach the meat and leaving maggots behind as they would leave.

How did the fly/maggot experiment prove spontaneous generation wrong?

this proved that for life to appear, there needs to be a another form of life prior to it. like maggots would come from flies, life comes from life

Who discovered the first microscope?

Anton Van Leeuwenhoek

What did Anton Van Leeuwenhoek observe?

Animalcules, was actually seeing microorganisms

What are animalcules?

little animals

What does the theory of Biogenesis state?

life comes from life

who developed biogenesis

Louis Pasteur

Pasteur’s test of spontaneous generation, process

Broth is placed in container with an ‘s’ flask to have air filtered, and it’s boiled so broth remains free of microorganisms; the curved neck is then removed and microorganisms grow in the broth

What did Pasteur prove and disprove through his experiment?

pasteur disproved spontaneous generation while proving the law of biogenesis

Who is considered the founder of microbiology?

Louis Pasteur

Pasteur’s contributions: Industrial Microbiology

Began the field of industrial microbiology (biotechnology), microbes are intentionally used to manufacture products

Pasteur’s contributions: Bacteria and Yeast cells fermentation of grape juice

discovered the bacteria ferment grape juice to produce acid, where as yeast cells ferment grape juice to produce alcohol

Pasteur’s contributions: Pasteurization

use of heat to kill pathogens and reduce the number of spoilage of microbes in food and beverages (asepsis)

Asepsis

the reduction of the number of microbes to a safe level on or in an object. To reach asepsis, we use aseptic techniques such as handwashing.

Who Performed the first Antiseptic Surgery?

Dr. Joseph Lister

Joseph Lister’s carbolic acid sprayer

Lister made the first antiseptic to disinfect wounds and spray the air of his operating theater with carbolic acid steam

Pasteurization

a heating and cooling process that makes food products safe to eat

Explanation of fermentation

microbes, due to metabolism, can change their extracellular environment by excretion of metabolic byproducts such as alcohol or lactic acids.

Fermentation led to the development of what theory?

the Germ Theory of Disease

Germ Theory led to what understanding?

many diseases are caused by microorganisms (viruses and bacteria)

Experiment by Pasteur and Koch led to an understanding of the …

presences of microorganisms and their relationship to diseases

Germ Theory of DIsease

microbes, due to metabolism, can change their extracellular environment by excretion of metabolic byproducts in the host which can cause disease

Who co-developed the Germ Theory of Disease?

Louis Pasteur and Robert Koch

1876- Koch’s 1st proof that microbe is able to cause disease

Bacillus antracis causes anthrax

Koch’s Postulates

suspected organism must always be found in diseased individual and never in healthy; must be cultivated in pure culture; pure cultures must cause same disease in suspectible animal; same organism must be re-isolated

The development of the Germ theory of disease led to the field of …

Medical Microbiology

How many microbes cause disease?

only about 1% of all microbes cause disease, the rest are beneficial to our world

Benefits of Bacteria

food manufacturing, research, protection, medicines/vaccines, bioremediation, manufacturing

Two types of cells

eukaryotic and prokaryotic

The cells is…

the basic unit of life

Characteristics of life: Metabolism

change

Characteristics of life: Adaptation due to DNA

how a cell can adapt to an environment with DNA modifications

Characteristics of life: Reproduction

Eukaryotic cells reproduce by mitosis; Prokaryotic cells reproduce by binary fission

Microscopy

study using microscopes to observe and learn about the microbial world

Type of Microscopes

Light and electron

Light Microscopes: Brightfield

easy to use; specimen detail is not so great; specimen has to be stained so it is killed during the staining procedure

Light Microscopes: Phase Contrast

uses a phase contrast condenser; you can maintain living specimen because the organism is naturally stained; specimen detail is good

Light Microscopes: Dark Field

used in conjunction with Treponema pallidum which causes syphilis; viewed as living specimen, cannot be stained by chemical or light; contains a dark condenser

Light Microscopes: Immunofluorescence

used in conjunction with immunology

Electron Microscope

takes training to learn how to use this microscope; scanning electron microscope (SEM) and transmission electron microscope (TEM); specimen is killed

Light Microscopes: What is used to make an image?

beams of visible light

Light Microscopes: How does it magnify objects?

light shines through an object and lenses magnify the image

Light Microscopes: How well can it magnify?

up to 100x

Light Microscopes: What can it magnify?

specimens must be thin and transparent. can be living or dead

Light Microscopes: What can it record?

full color images. can be captured using digital camera or computer.

Electron Microscopes: What is used to make an image?

beams of electron emitted in a vacuum

Electron Microscopes: How does it magnify objects?

electron are transmitted through or scan the outside of the object

Electron Microscopes: How well can it magnify?

usually 35,000x but can be 1 million x

Electron Microscopes: What can it magnify?

fixed specimens must be dead, dry, and stained with heavy metals

Electron Microscopes: What can it record?

computer capture digital black and white images that can be colorized

What charge are cells overall?

all cells are overall negatively charged

Stains: Carbolfuschin

basic dye (+), red

Stains: Crystal Violet

basic dye (+), purple

Stains: Methylene Blue

basic dye (+), blue

Stains: Safranin

basic dye (+), reddish-pink

Stains: Malachit Green

basic dye (+), weak, green

Stains: India ink

acidic dye (-), black

What stain can a dark field condenser be substituted by and why?

it can be substituted by india ink because it is black and negatively charged and so it the cell, so the cell will reject the ink and the background will only be stained black

3 types of stains

simple, differential, and negative

Simple stain

uses one basic dye; stain allows you to see the specimen; doesn’t tell you anything about the cells

Differential Stain

uses two different colored basic dyes; the stain tell you something about a cells structure; gram stain and acid-fast stain

Gram Stain

answer the question whether or not cell had a thick or thin cell wall

What bacteria does not contain a cell wall?

mycoplasma spp, mycoplasma pneumonaie which causes walking pleumonia

Fuctions of cells wall

protections, cell shape

Cell Shape: Cocci

round; staphylococcus aureus

Cell Shape: Bacillus

rod; E. coli

Cell Shape: Spiral

wavy; Traponema pallidum

Gram Stain procedure: Purpose

to identify gram + vs gram -

Gram Stain procedure: order

primary stain, mordant, decolorizer, counterstain

Gram Stain procedure: Steps (dyes, etc.)

crystal violet, gram’s iodine, acetone alcohol, safranin

Gram Stain procedure: Gram (+) color order

purple, purple, purple, purple; thick cell wall

Gram Stain procedure: Gram (-) color order

purple, purple, clear, red; thin cell wall

Gram Stain procedure: Primary Stain

a stain that is applied first in all gram stain procedures

Gram Stain procedure: Mordant

a chemical or procedure that helps primary stain stick to the cells

Gram Stain procedure: Decolorizer

removes color of stain if it can be removed

Gram Stain procedure: Counterstain

a different colored stain to determine wall thickness

Gram (+) Structure: Outer membrane

absent

Gram (+) Structure: Peptidoglycan layer

thick- causes more dye retention

Gram (+) Structure: Inner or cell membrane

present

Gram (-) Structure: Outer membrane

present