Scope of MicrobiologyScope of MicrobiologyScope of MicrobiologyScope of Microbiology
MicrobiologyMicrobiology
Micro: Small, Bio: Live, Logy: ScienceMicro: Small, Bio: Live, Logy: Science Study of organisms too small to be seen by Study of organisms too small to be seen by
the naked eye.the naked eye.
MicroorganismsMicroorganisms
Bacteria, viruses, fungi, algae, protozoa and Bacteria, viruses, fungi, algae, protozoa and helminthes. helminthes.
Branches of StudyBranches of StudyBranches of StudyBranches of Study
BacteriologyBacteriology Study of bacteriaStudy of bacteria
Mycology Mycology Study of fungi and yeastStudy of fungi and yeast
Virology Virology Study of virusesStudy of viruses
Parasitological Parasitological Study of parasitic protozoan and Study of parasitic protozoan and helmintheshelminthes
Immunology Immunology Study of the humoral and cellular Study of the humoral and cellular immune response to immune response to
disease disease agents and agents and allergensallergens
Importance of MicrobiologyImportance of MicrobiologyImportance of MicrobiologyImportance of Microbiology
First bacteriaFirst bacteria
Photosynthesis and decompositionPhotosynthesis and decomposition
Human use of microorganismsHuman use of microorganisms
Infectious diseasesInfectious diseases
Modern Uses of MicrobesModern Uses of MicrobesModern Uses of MicrobesModern Uses of Microbes
Biotechnology:Biotechnology: Production of food and chemicalsProduction of food and chemicals
Genetic engineering:Genetic engineering: Molecular biology and Molecular biology and recombinant DNA techniquesrecombinant DNA techniques
Gene therapy: Gene therapy: Replaces missing or defective Replaces missing or defective genes in human cells through genetic engineering.genes in human cells through genetic engineering.
Infectious DiseasesInfectious DiseasesInfectious DiseasesInfectious Diseases
Worldwide infectious disease statistics
United States Public Health Service (USPHS) - agency where notifiable diseases are reported
Centers for Disease Control (CDC)-collects disease data around the U.S. and publishes the MMWR (Morbidity and Mortality Weekly Report)
World Health Organization (WHO)-medical arm of the U.N., monitors diseases worldwide.
Microbial TaxonomyMicrobial TaxonomyMicrobial TaxonomyMicrobial Taxonomy
Traditional Whittaker 5 Kingdom System
Microbial TaxonomyMicrobial TaxonomyMicrobial TaxonomyMicrobial Taxonomy
Woese-Fox 3 Domain System
NomenclatureNomenclatureNomenclatureNomenclature
Each organism has two names: the genus and Each organism has two names: the genus and
speciesspecies
Italicized or underlineItalicized or underline
Genus name is capitalized and species in lower Genus name is capitalized and species in lower case.case.
Scientific NamesScientific NamesScientific NamesScientific Names
Staphylococcus aureusStaphylococcus aureusDescribes clustered arrangement of cells and Describes clustered arrangement of cells and golden yellow color of coloniesgolden yellow color of colonies
Escherichia coliEscherichia coliHonors the discoverer, Theodor Escherichia Honors the discoverer, Theodor Escherichia and describes its habitat, the colon.and describes its habitat, the colon.
After the first use, scientific names may be After the first use, scientific names may be abbreviated with the first letter of the genus abbreviated with the first letter of the genus and full letters of the species (Ex: and full letters of the species (Ex: E. coliE. coli))
General CharacteristicsGeneral CharacteristicsGeneral CharacteristicsGeneral Characteristics
Prokaryotes Prokaryotes
EukaryotesEukaryotes
A cellular agentsA cellular agents Genomes contain either Genomes contain either DNA or RNA; e.g. Virus, DNA or RNA; e.g. Virus,
newer agent is proteinaceousnewer agent is proteinaceous
Differences between prokaryotes and eukaryotesDifferences between prokaryotes and eukaryotes
ProkaryotesEukaryotes
Cell size0.2-2 micrometerIn diameter
10-100 micrometerIn diameter
NucleusNo nuclear membrane or nucleoli (nucleoid)
True nucleus, consisting of nuclear membrane &
nucleoli
Cell DivisionBinary FissionMitosis
Cell wallUsually present; chemically complex
(typical bacterial cell wall includes peptidoglycan)
When present, chemically simple
Cell TypesCell TypesCell TypesCell Types
Comparative Cellular Structures of Microbes
The MicrobesThe MicrobesThe MicrobesThe Microbes
Viruses Protozoa
Bacteria
Bacteriophage
Algae
SpirochaetesCyanobacteria
Fungi
Size of MicrobesSize of MicrobesSize of MicrobesSize of Microbes
Microbes vary in size ranging from 10 nm (nanometers) to 100 mu (micrometers) to the macroscopic.
Viruses in nm = 10-9 m (meter)
Bacteria in um = 10-6 m
Helminths in mm = 10-3 m
BacteriaBacteria
Prokaryotes
Peptidoglycan cell walls
Binary fission
Eg., Escherichia coli
FungiFungiFungiFungi
Eukaryotes
Chitin cell walls
Molds and mushrooms
are multicellular
Yeasts are unicellular
ProtozoaProtozoaProtozoaProtozoa
Eukaryotes Mostly saprobes and
commensals May be motile by means of
pseudopod, cilia or flagella
HelminthesHelminthesHelminthesHelminthes
Eukaryotes Multicellular animals Parasitic flatworms and roundworms
called helminthes Microscopic stages in life cycles
AlgaeAlgaeAlgaeAlgae
Eukaryotes
Cellulose cell walls
Photosynthetic Produce molecular oxygen and
organic compounds
Part of food chain
VirusesVirusesVirusesViruses
A cellular
Obligate intracellular parasites
Genome consist of DNA or RNA
Surrounded by protein coat
May be enclosed in lipid envelope
The First MicroscopeThe First MicroscopeThe First MicroscopeThe First Microscope
Microbes were first observed by Antonie van Leeuwenhoek using a simple microscope (ca. 1673)
Reported his “animalcules” to the Royal Society of London
Spores and SterilizationSpores and SterilizationSpores and SterilizationSpores and Sterilization
John Tyndall: John Tyndall: Some microbes in dust and Some microbes in dust and
air were resistant to heat air were resistant to heat
Ferdinand Cohn:Ferdinand Cohn: Discovered and described Discovered and described endospores endospores
Sterile:Sterile: Complete removal of all life forms Complete removal of all life forms including endospores including endospores
Louis PasteurLouis PasteurLouis PasteurLouis Pasteur
Microbes caused Microbes caused
fermentationfermentation
Pasteurization:Pasteurization: Prevent Prevent
spoilagespoilage
Antiseptics and Hand WashingAntiseptics and Hand WashingAntiseptics and Hand WashingAntiseptics and Hand Washing
1860s:1860s: Joseph Lister:Joseph Lister: Used, carbolic Used, carbolic
acid, a chemical antiseptic to prevent acid, a chemical antiseptic to prevent
surgical wound infectionssurgical wound infections
Ignaz Semmelweis: Ignaz Semmelweis: Introduced hand Introduced hand washing as a means of preventing transfer washing as a means of preventing transfer of puerpueral sepsis in obstetrical patientsof puerpueral sepsis in obstetrical patients
Infection and DiseaseInfection and DiseaseInfection and DiseaseInfection and Disease
Infection:Infection: Entry of a microbe into the hostEntry of a microbe into the host
Disease:Disease: Appearance of signs and Appearance of signs and symptomssymptoms
Pathogen:Pathogen: An infectious agentAn infectious agent
Opportunistic pathogen:Opportunistic pathogen: A microbe that cause A microbe that cause disease in immuno compromised hosts or when the disease in immuno compromised hosts or when the normal microbiota is alterednormal microbiota is altered