Chapter 1 Microbiology: Humans and the Microbial World

Microbiology

The study if microscopic organisms, known as microorganisms or microbes

Bacteria

Single-celled prokaryotic organisms with diverse metabolic capabilities

Archaea

Similar in appearance to bacteria but genetically and biochemically different

Fungi

Includes mold, yeasts, and mushrooms: mostly multicellular and eukaryotic

Protozoa

single-celled eukaryotes, often motile and found in aquatic environments, no rigid cell walls, most are motile.

Algae

plant-like eukaryotes that perform photosynthesis, single celled or multicellular

Viruses

Viroid

Prions

acellular infectious agents that do not fall under traditional definitions of life

Anthony van Leeuwenhoek

Father of Microbiology, created the microscope, observed animalcules

Robert Hooke

First to describe cells, credited with discovery of microbes

Francesco Redi

Challenged the concept of spontaneous generation.

Spontaneous Generation

Belief that life can arise from non-living matter.

John Needham

Boiled broth in sealed flasks, organisms still grew- supporting spontaneous generation.

Lazzaro Spallanzani

Recreated Needham’s experiments with a tighter seal and longer boiling times- no organisms appeared. Supporting Biogenesis.

Louis Pasteur

Disproved spontaneous generation using an S shaped flask AND the first to show that fermentation was caused by microbes.

Robert Koch

Developed postulates of disease, Identified specific pathogens including anthrax, TB and Cholera.

Koch’s Postulates

1. The microorganism must be found in abundance in all organisms suffering from the disease, but should not be found in healthy organisms.

2. The microorganism must be isolated from a diseased organism and grown in pure culture.

3. The cultured microorganism should cause disease when introduced into a healthy organism.

4. The microorganism must be reisolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent.

Florence Nightingale

Practiced aseptic technique in nursing

Ignaz Semmelweis

Showed that hand washing decreased puerperal sepsis

Joseph Lister

Implemented aseptic technique in surgery.

Biogenesis

Principal that life only arises from existing life.

Germ Theory of Disease

Diseases are caused by organisms. Concept came from Pasteur.

Scientific Method

describes the process of science.

Human Microbiome

bacteria inside of us and on us.

Roles of Human Microbes

• Prevent Disease by competing with other disease-causing microbes

• Aid in Digestion

• Promote development of immune system

• May affect brain chemistry and body weight.

Microorganisms in the Environment

• Recycling of Nutrients

• Nitrogen Fixation

• Decomposers of Natural Material

Commercial Benefits of Microrganisms

• Food Production

  • yeast, beer, yogurt

• Biodegradation

• Bacteria Synthesize commercially valuable products

• Biotechnology

• Genetic Engineering

Beneficial/Not Harmful

Most microorganisms are _______.

Cause of resurgence of eradicated diseases

• People not getting vaccinated

• mutations

• People coming from other countries already infected

Prokaryotes & Eukaryotes

Two Basic Cell Structures

• Bacteria (Prokaryotes)

• Archaea (Prokaryotes)

• Eukarya (Eukaryotes)

All Living Things can be classified into these 3 domains

Prokaryotic Cells

Do not have a membrane bound nucleus, unicellular, microscopic, simple, bacteria & archaea

Chloroplasts, Nucleus, Peptidoglycan

The presence of which of the following would be helpful in distinguishing a prokaryote from a eukaryote

Bacteria

Unicellular, Prokaryotic, contain peptidoglycan in cell walls, found in diverse environments, many move with flagella, multiply via binary fission

Archaea

Unicellular, Prokaryotic, No peptidoglycan instead contain pseudopeptidoglycan, found in extreme environments.

Eukarya

Multicellular, Cells with a bound nucleus

Virus

Not made of cells, composed of genetic materials, require host cells for replication. Contains EITHER RNA or DNA

Viroid

Cellular RNA molecules with no protein coat, infect plants and disrupt cellular metabolism

Prions

infectious proteins that cause neurodegenerative diseases, alter normal proteins. No DNA or RNA

Coccus

spherical cells, flattened on one end or oval

Bacillus

Rod shaped, cylindrical cell

Spirillum

curved rod long enough to create a spiral

Fungi

Primary decomposers, range from single-cellular yeasts to multicellular filamentous molds

Helminths

parasitic worms that live at the expense of the hosts. Include roundworms, tapeworms and flukes

Inactive

Outside a cell, viruses are

Penicillin

affects the synthesis of phospholipids, thereby producing weak membranes and lysis of the bacteria.

The Golden Age of Medical Microbiology

occurred during the late 1800's to early 1900's, is a time when the knowledge of and techniques to work with bacteria blossomed AND was when people realized that diseases could be caused by invisible agents.

The work of Tyndall and Cohn

was used to explain why others investigating spontaneous generation had obtained results that were opposite of those obtained by Pasteur.