Microbiology Life as a Single Cell Where does “disease” come from? Microbes and Mankind

MicrobiologyMicrobiology

Life as a Single CellLife as a Single Cell

Where does Where does ““disease” come disease” come from?from?

Microbes and MankindMicrobes and Mankind

Some Key Terms:Some Key Terms: DiseaseDisease a condition of the living animal or plant body or of one of a condition of the living animal or plant body or of one of

its parts that impairs normal functioning and is typically its parts that impairs normal functioning and is typically manifested by distinguishing signs and symptoms manifested by distinguishing signs and symptoms

Infectious DiseaseInfectious Disease A disease capable of spreading rapidly to others A disease capable of spreading rapidly to others PathogenPathogen a specific living causative agent of disease a specific living causative agent of disease ParasiteParasite an organism living in, with, or on another organism as a an organism living in, with, or on another organism as a

source of nutrition / energysource of nutrition / energy

There are 5 basic forms of There are 5 basic forms of infectious disease.infectious disease.

VirusesViruses BacteriaBacteria Protozoans (animal-like protists)Protozoans (animal-like protists) FungiFungi Invertebrate parasites Invertebrate parasites

The Micro Scale 10The Micro Scale 10-6-6mm Single celledSingle celled or unicellular life exists in or unicellular life exists in

four Kingdoms of life.four Kingdoms of life. Kingdom Monera – the bacteriaKingdom Monera – the bacteria Kingdom Fungi – yeast & moldKingdom Fungi – yeast & mold Kingdom Protista – the ProtozoansKingdom Protista – the Protozoans Kingdom Archaea – archaeans Kingdom Archaea – archaeans Microbial lifeMicrobial life exists in five Kingdoms exists in five Kingdoms Kingdom Animalia – various Kingdom Animalia – various

invertebratesinvertebrates

Requirements for “micro-life” Requirements for “micro-life”

Characteristics of Living Characteristics of Living ThingsThings

Reproduce (make more of its kind)Reproduce (make more of its kind) Obtain energy (heterotrophs/autotrophs)Obtain energy (heterotrophs/autotrophs) Metabolize (breaking down and building up)Metabolize (breaking down and building up) Eliminate wasteEliminate waste Made of cells (Eukarya/Prokarya/Archaea)Made of cells (Eukarya/Prokarya/Archaea) Genetic information (DNA)Genetic information (DNA) Part of a food chain (producer / consumer)Part of a food chain (producer / consumer) All have to die (have a life cycle)All have to die (have a life cycle) Adapt to environment (individuals & group)Adapt to environment (individuals & group) Grow (size) and develop (complexity)Grow (size) and develop (complexity)

Where does disease come Where does disease come from?from?

What happens to us on the macro-What happens to us on the macro-scale depends on what is happening scale depends on what is happening

to us on the micro-scale.to us on the micro-scale.

Microbes/Parasites need to feed to Microbes/Parasites need to feed to get raw materials and to get energy.get raw materials and to get energy.

We are food.We are food.

Microbes/Parasites - Genetics - Microbes/Parasites - Genetics - EnvironmentEnvironment

The Virus QuestionsThe Virus Questions

Are Viruses classified as living Are Viruses classified as living things or not?things or not?

Currently – NO.Currently – NO. A Taxonomy has been builtA Taxonomy has been built

The Virus QuestionsThe Virus Questions

Why is there a debate?Why is there a debate? Viruses meet Viruses meet some but not some but not all criteria all criteria

of living thingsof living things

Respond to the environment ? Respond to the environment ? Move under their own power ? Move under their own power ? Influence / change host they live in ? Influence / change host they live in ? Mimic living infections ? Mimic living infections ? Have ability to replicate ? Have ability to replicate ? Age or die under optimal conditions ? Age or die under optimal conditions ? Have a metabolism ? Have a metabolism ? Grow or develop ? Grow or develop ? Contain organic molecules (carbon) ? Contain organic molecules (carbon) ? Have genetic information - DNA Have genetic information - DNA or or

RNA ?RNA ? Adapt as a group over time ?Adapt as a group over time ? Eat ? Eat ? Produce by-products / waste Produce by-products / waste

products ? products ? Reproduce outside of host assistance ?Reproduce outside of host assistance ? Can be killed / inactivated ?Can be killed / inactivated ? Produce and consume energy ?Produce and consume energy ? Made of cells ?Made of cells ?

NO

NOYES

YESYES

NONO

NOYES

YES

YESNO

NONO

YESNO

NO

Virus QuestionsVirus Questions If they are not alive, then what else If they are not alive, then what else

would they be?would they be? Viruses are ultramicroscopic non-Viruses are ultramicroscopic non-

cellular genetic elements (nucleic cellular genetic elements (nucleic acids – DNA/RNA) surrounded by a acids – DNA/RNA) surrounded by a protein coat, which are of biological protein coat, which are of biological significance.significance.

Renegade / parasitic DNA & RNARenegade / parasitic DNA & RNA

Visualizing VirusesVisualizing Viruses

Seeing the “ultramicroscopic” is only Seeing the “ultramicroscopic” is only possible using the electron microscopepossible using the electron microscope

The probe is the electron – not lightThe probe is the electron – not light

The images are in black and white The images are in black and white because there is no visible light involved.because there is no visible light involved.

Helical Symmetry - Helical Symmetry - Coiled spiralCoiled spiral

The The helical helical

structurstructure of the e of the

rigid rigid tobacco tobacco mosaic mosaic virus virus rod rod

Icosahedral SymmetryIcosahedral Symmetry 20 equilateral triangle faces20 equilateral triangle faces

SPIKES

Sugarcane Fiji disease virus

PolyhedrPolyhedral Virusal Virus

BacteriophagesBacteriophages Icosahedral head, helical tail, fibers & pinsIcosahedral head, helical tail, fibers & pins

Phage – Transmission Electron Microscope

Envelope enclosed - Icosahedral Envelope enclosed - Icosahedral SymmetrySymmetry

Virus VocabVirus Vocab

Viral Envelope – membrane structure - from hostViral Envelope – membrane structure - from host Spikes-projections from the envelope, attachmentSpikes-projections from the envelope, attachment Unique viral proteins - in lipid bi-layer. Used to Unique viral proteins - in lipid bi-layer. Used to

complete attachment and invade host cellcomplete attachment and invade host cell

Viral Infection/ReplicationViral Infection/Replication Transmission – Airborne / respiratory, Transmission – Airborne / respiratory,

blood-borne / body fluidsblood-borne / body fluids Attachment – host and viral receptors uniteAttachment – host and viral receptors unite Viral - protein coat, glycoproteins, envelope,Viral - protein coat, glycoproteins, envelope,

spikesspikes Host - pili, cilia, flagella, membrane proteinsHost - pili, cilia, flagella, membrane proteins

Penetration of the cell membranePenetration of the cell membranephagocytosis - active transport by host cellphagocytosis - active transport by host cell

blending - envelope with cell membraneblending - envelope with cell membraneinject - bacteriophage tail & sheath uses inject - bacteriophage tail & sheath uses

enzymes to open a hole in the cell wall/membraneenzymes to open a hole in the cell wall/membrane

The End

and a new beginning…

1

2

3

4

5

6

Nucleus

Genomes

Ribosome

Capsids

TransmissionAttachmentPenetration

Genome

Capsid

Icosahedral

Golgi body

Phagocytosis

ReleaseRelease Biological exhaustion of the cell - Biological exhaustion of the cell -

disintegrationdisintegration Cell lysis - cell is physically Cell lysis - cell is physically

overloaded with viruses and the overloaded with viruses and the cell membrane burstscell membrane bursts

Cell to cell passage – virus moves Cell to cell passage – virus moves from one cell to the next without from one cell to the next without passing through the environmentpassing through the environment

Budding – (see next slide)Budding – (see next slide)

•Budding - nucleocapsid moves to cell membrane where it forces itself out of the cell taking a portion of the cell with it.

ReleaseRelease

Antiviral AgentsAntiviral Agents Antibiotics do not work against viruses Antibiotics do not work against viruses

because they do not have the cellular because they do not have the cellular functions antibiotics targetfunctions antibiotics target

Nucleotide analogs - bind to viral DNA / RNANucleotide analogs - bind to viral DNA / RNA Acyclovir - prevent viral replication of herpesAcyclovir - prevent viral replication of herpes Azidothymidine (AZT) - prevent viral Azidothymidine (AZT) - prevent viral

replication of HIVreplication of HIV Gamciclovir - cytomegalovirusGamciclovir - cytomegalovirus Amantadine - influenzaAmantadine - influenza

Interferon - proteins, produced naturally by Interferon - proteins, produced naturally by an infected host cell. Do not help infected an infected host cell. Do not help infected cell, but protects neighboring cellscell, but protects neighboring cells

Viral VaccinesViral Vaccines Preventive measure - not treatmentPreventive measure - not treatment Injection / oral dose to prime the immune Injection / oral dose to prime the immune

systemsystem antigen - host makes antibodyantigen - host makes antibody inactivated virus - dead from physical/chemical inactivated virus - dead from physical/chemical

treatmenttreatment attenuated virus - live, weakened virus - slow attenuated virus - live, weakened virus - slow

replication, no symptoms of the diseasereplication, no symptoms of the disease synthetic antigens - genetically synthetic antigens - genetically

engineered antigensengineered antigens examples: polio, yellow fever, examples: polio, yellow fever, measles, measles, rubella, hepatitis, rubella, hepatitis, smallpoxsmallpox

Kingdom MoneraKingdom Monera Formerly know as Prokaryotae, Formerly know as Prokaryotae,

all Monerans are prokaryotic bacteriaall Monerans are prokaryotic bacteria Heterotrophs - parasitic & saprobphiticHeterotrophs - parasitic & saprobphitic Autotrophs - photosynthetic & Autotrophs - photosynthetic &

chemosyntheticchemosynthetic All are microscopic - some are All are microscopic - some are

ultramicroscopicultramicroscopic Most are motile - flagella, cilia, slimy Most are motile - flagella, cilia, slimy

glidersgliders Some are useful or harmless to humans, Some are useful or harmless to humans,

some cause infection/diseasesome cause infection/disease

Morphology Morphology - Basic - Basic shapesshapes

Cocci (coccus) = sphericalCocci (coccus) = spherical Bacilli (bacillus) = rod-likeBacilli (bacillus) = rod-like Vibrio = commaVibrio = comma Spirochete = flexible wavy shapeSpirochete = flexible wavy shape Spirochetes have a worm-like, spiral-shaped form, and wiggle Spirochetes have a worm-like, spiral-shaped form, and wiggle

vigorously when viewed under a microscopevigorously when viewed under a microscope Spirillum = corkscrewSpirillum = corkscrew Anywhere from less than one to five helical turns. Anywhere from less than one to five helical turns. They have rigid helical cell structure as opposed to the flexible cell They have rigid helical cell structure as opposed to the flexible cell

structure of spirochetes.structure of spirochetes.

diplococcus = pair of coccidiplococcus = pair of cocci streptococcus = chain of coccistreptococcus = chain of cocci streptobacilli = chain of bacillistreptobacilli = chain of bacilli tetracoccus = four cocci in a cubetetracoccus = four cocci in a cube staphylococcus = grapelike clusterstaphylococcus = grapelike cluster

I’mWavy

TetradsTetrads

Phylum EubacteriaPhylum Eubacteria ““the true bacteria”the true bacteria” mostly heterotrophs mostly heterotrophs

Decomposers, saprobes, parasites, symbionts Decomposers, saprobes, parasites, symbionts

all have a complex carbohydrate cell all have a complex carbohydrate cell walls made of walls made of peptidoglycan peptidoglycan and at and at least one inner membraneleast one inner membrane

common causes of diseasecommon causes of disease example: example: Streptococcus aureusStreptococcus aureus

Other Moneran PhylaOther Moneran Phyla

Prochlorobacteria – small, photosyntheticProchlorobacteria – small, photosynthetic

Cyanobacteria – formerly blue-green Cyanobacteria – formerly blue-green algaealgae

Archaebacteria – now Kingdom Archaea, Archaebacteria – now Kingdom Archaea, live in extreme environmentslive in extreme environments

    The archaea very much resemble The archaea very much resemble bacteria, so much so that they were bacteria, so much so that they were once thought to be a weird group of once thought to be a weird group of bacteria. However, by studying bacteria. However, by studying archaeal cells on a molecular level, archaeal cells on a molecular level, scientists have now come to think scientists have now come to think that these "weird bacteria" actually that these "weird bacteria" actually are a separate category of life are a separate category of life altogether. In fact, in some ways, altogether. In fact, in some ways, archaea are more like you than archaea are more like you than they are like bacteria!they are like bacteria!

Kingdom ArchaeaKingdom Archaea

    The archaea very much The archaea very much resemble bacteria, so much so resemble bacteria, so much so that they were once thought to be that they were once thought to be a weird group of bacteria. a weird group of bacteria. However, by studying archaeal However, by studying archaeal cells on a molecular level, cells on a molecular level, scientists have now come to think scientists have now come to think that these "weird bacteria" that these "weird bacteria" actually are a separate category actually are a separate category of life altogether. In fact, in some of life altogether. In fact, in some ways, archaea are more like you ways, archaea are more like you than they are like bacteria!than they are like bacteria!

Archeaens Distinctives -Archeaens Distinctives -ExtremophilesExtremophiles

Many archaeans thrive in conditions that Many archaeans thrive in conditions that would kill other creatures: boiling water, would kill other creatures: boiling water,

super-salty pools, sulfur-spewing super-salty pools, sulfur-spewing volcanic vents, acidic water and deep in volcanic vents, acidic water and deep in Antarctic ice. These types of archaea are Antarctic ice. These types of archaea are often labeled "extremophiles," meaning often labeled "extremophiles," meaning creatures that love extreme conditions. creatures that love extreme conditions.

Kingdom Profiles - ArchaeaKingdom Profiles - Archaea

Archaean DistinctivesArchaean DistinctivesBiochemistry of the cell membrane

Archaean DistinctivesArchaean DistinctivesStructure of the ribosomes

Archaean DistinctivesArchaean Distinctives

Alternate Sources of nutrition:

Hydrogen, Sulfur, Carbon Dioxide

Moneran PartsMoneran Parts Most have a cell wall - some just a defective layerMost have a cell wall - some just a defective layer Prevents cell from exploding in a hypotonic solutionPrevents cell from exploding in a hypotonic solution Provides some protection against viruses, other Provides some protection against viruses, other

bacteria, antibiotics, host immune system, bacteria, antibiotics, host immune system, environment, dehydration, disinfectionenvironment, dehydration, disinfection

adhere to surfacesadhere to surfaces Cell walls are classified as Gram + or Gram -Cell walls are classified as Gram + or Gram - Gram +: variable capsule, thick peptidoglycan, Gram +: variable capsule, thick peptidoglycan,

membranemembrane Gram -: variable capsule, outer lippoprotein Gram -: variable capsule, outer lippoprotein

membrane, sheet of peptidoglycan, periplasam, inner membrane, sheet of peptidoglycan, periplasam, inner membranemembrane

Bacterial GrowthBacterial Growth Very short generation time (doubling time)Very short generation time (doubling time) 20 min for the fastest20 min for the fastest Average time is 30 min to 3 hoursAverage time is 30 min to 3 hours

Lag phase - bacteria become accustomed to new Lag phase - bacteria become accustomed to new environment, new cells replace dying cells, slope upenvironment, new cells replace dying cells, slope up

Logarithmic (log) phase - optimal level of growth, Logarithmic (log) phase - optimal level of growth, population doubles rapidly, straight ascending line.population doubles rapidly, straight ascending line.

Stationary phase - reproduction offsets death (from Stationary phase - reproduction offsets death (from accumulation of waste, lack of nutrients, unfavorable accumulation of waste, lack of nutrients, unfavorable environment and host immune response. environment and host immune response.

Death phase - decline in populationDeath phase - decline in population

Antibiotic ResistanceAntibiotic Resistance Resistance is being able to defeat the Resistance is being able to defeat the

antibiotic by, making an enzyme that antibiotic by, making an enzyme that destroys the antibiotic (penicillinase) -or- destroys the antibiotic (penicillinase) -or- making a molecule that binds to the active making a molecule that binds to the active site of the antibiotic.site of the antibiotic.

When exposed to antibiotics, the susceptible When exposed to antibiotics, the susceptible cells in the population die - the resistant cells cells in the population die - the resistant cells multiply rapidly when competition is gone.multiply rapidly when competition is gone.

Resistant strains become widespread.Resistant strains become widespread. Sometimes even non-resistant bacteria living Sometimes even non-resistant bacteria living

near resistant ones can survivenear resistant ones can survive drug resistant genes can be transferred drug resistant genes can be transferred

during conjugationduring conjugation

Controlling Bacterial DiseaseControlling Bacterial Disease

Lister - listerine is Lister - listerine is named for himnamed for him

pioneered hygiene pioneered hygiene & sanitation& sanitation

heating to 60 C for heating to 60 C for 30 min destroys 30 min destroys exotoxins and kills exotoxins and kills most bacteria.most bacteria.

•Alxandar Flemming - discovered 1st antibiotic in 1929

•discovered penicillin growing on a moldy petri dish - isolated “antibacterial” agent

ProtozoansProtozoans

The animal-like, heterotrophic, The animal-like, heterotrophic, unicellular, Protistsunicellular, Protists

endoplasm

ectoplasm

Hyalin cap

Giardia - common beaver parasite

Giardia – Scanning Electron microscope

Compound lightmicroscope

Plasmodium, causes malaria - Plasmodium, causes malaria - #1#1 infectious infectious human diseasehuman disease

Do you know anyone with malaria?Why not?

Toxoplasma gondii - 1/2 of all Americans Toxoplasma gondii - 1/2 of all Americans have had this sporazoa at one time - found have had this sporazoa at one time - found

in cats & pork.in cats & pork.Not serious for healthy adults, but very Not serious for healthy adults, but very dangerous to newborns, fetus & AIDS dangerous to newborns, fetus & AIDS

patients.patients.

This diagramshows the possible stepsin the complicatedlife-cycle of Toxoplasma

1) Eukaryotic1) Eukaryotic 2) Non-photosynthetic, heterotrophic 2) Non-photosynthetic, heterotrophic

absorptive absorptive 3) Lack tissue differentiation, 3) Lack tissue differentiation,

composed of similar cells – hyphae composed of similar cells – hyphae 4) Have cell walls made of chitin – 4) Have cell walls made of chitin –

polysaccharide, strength molecule polysaccharide, strength molecule 5) Propagate by spores: may be 5) Propagate by spores: may be

produced sexually or asexuallyproduced sexually or asexually 6) Non-motile6) Non-motile

Kingdom FungiKingdom Fungi6 General Characteristics6 General Characteristics

Hyphae – a Fungus Hyphae – a Fungus originaloriginal

Hyphae – a closer lookHyphae – a closer look

Hyphae – a microsopic viewHyphae – a microsopic view

Fungi FeedingFungi FeedingParasitesParasites -- specialized hyphae called specialized hyphae called

“haustoria” pierce the cell membranes “haustoria” pierce the cell membranes of host cells and feed directly from of host cells and feed directly from themthem

Typical Typical Deuteromycota Deuteromycota MyceliumMycelium

Thursh - Thursh - Angular cheilitisAngular cheilitis

Thrush - Thrush - Atrophic candidiasisAtrophic candidiasis

Thrush - Thrush - Atrophic candidiasisAtrophic candidiasis

Thrush - Thrush - Atrophic candidiasisAtrophic candidiasis

Babies with ThrushBabies with Thrush

Athlete’s Foot - Moccasin PatternAthlete’s Foot - Moccasin Pattern

Athlete’s Foot - Athlete’s Foot - Craks & FissuresCraks & Fissures

Onychomycosis – Toenails & Onychomycosis – Toenails & fingernailsfingernails

submitted by Stephanie Johnson class ‘04

What can you do ?

Athlete’s Foot - Advanced Athlete’s Foot - Advanced SpreadSpread

Ringworm - Basic Lesion PatternRingworm - Basic Lesion Pattern

Ringworm - AnkleRingworm - Ankle

Ringworm - Ringworm - BackBack

Ringworm – Face & HeadRingworm – Face & Head

Ringworm - Ringworm - LegsLegs

Ringworm - FeetRingworm - Feet

Ringworm - Feet 77 year old Ringworm - Feet 77 year old womanwoman

Ringworm - More Nappy Old Ringworm - More Nappy Old ToesToes

Three Classes:

Turbellaria - free living flatworms

Trematoda - parasitic flukes

Cestoda - tapeworms

Kingdom Anamalia - Phylum Kingdom Anamalia - Phylum PlatyhelminthesPlatyhelminthes

Oral Sucker

Pharynx

Two Part Digestive Tract

Class Trematoda Sheep Liver Class Trematoda Sheep Liver FlukeFluke

Oral Sucker

Ventral Sucker

Class Trematoda Chinese Liver Class Trematoda Chinese Liver FlukeFluke

Kingdom Anamalia - Phylum Kingdom Anamalia - Phylum Platyhelminthes Platyhelminthes - Class - Class CestodaCestoda

Scolex

Young Progottid

Old Progottid

can grow up to 30 feet – length of whole intestine

Kingdom Anamalia - Phylum Kingdom Anamalia - Phylum Platyhelminthes Platyhelminthes - Class - Class CestodaCestoda

Scolex

Suckers

Hooks

A tapeworms fancy A tapeworms fancy attachment equipmentattachment equipment

Kingdom Kingdom Anamalia - Anamalia - Phylum Phylum PlatyhelminthPlatyhelminthes es - Class - Class CestodaCestoda

Suckers

how do you get a tape how do you get a tape worm?worm?

Urban MythsUrban Myths A young woman had tried all kinds of A young woman had tried all kinds of

diets that didn't work, and finally she diets that didn't work, and finally she decided to try diet pills. They made decided to try diet pills. They made her lose so much weight all at once her lose so much weight all at once that she was really happy. Then one that she was really happy. Then one night, when she was lying in bed night, when she was lying in bed with her husband, a tapeworm with her husband, a tapeworm crawled right out of her nose. It had crawled right out of her nose. It had made her sick and caused her to lose made her sick and caused her to lose so much weight all of a sudden.so much weight all of a sudden.

Urban MythsUrban Myths

Kingdom Anamalia – Kingdom Anamalia – Phylum NematodaPhylum Nematoda

Examples:Round worms, pinworms, filarial worms (elephantiosis), trichinella (trichinosis)hookworm

HookwormHookworm

Are round worms dangerous?

There have been cases of human illness caused by the ingestion of live Phocanema

or Anisakis larvae in countries where raw or lightly cured fish is commonly eaten. By 1980,

there had been only one reported case of illness in the United Kingdom caused by

larval round worms from fish; this is because in the UK fish products are normally cooked

before consumption.

Toxocara canisToxocara canis is the predominant cause is the predominant cause of a serious condition called “Visceral of a serious condition called “Visceral Larva Migrans” in humans. Most victims Larva Migrans” in humans. Most victims are children. They are infected by are children. They are infected by inadvertantly consuming worm eggs in inadvertantly consuming worm eggs in soil (typically by getting dirty fingers in soil (typically by getting dirty fingers in their mouths).  The worm is not present in their mouths).  The worm is not present in its correct host but tries to complete its its correct host but tries to complete its life cycle anyway. The worm gets lost in life cycle anyway. The worm gets lost in the human body (classically in the eye), the human body (classically in the eye), dies, and generates an extreme dies, and generates an extreme inflammatory reaction. If the worm dies inflammatory reaction. If the worm dies within the human eye, blindness usually within the human eye, blindness usually results.results.

For this reason, it is important for parents For this reason, it is important for parents to be aware of this hazard.  Proper hand-to be aware of this hazard.  Proper hand-washing will prevent infection. Monthly washing will prevent infection. Monthly pet deworming will reduce environmental pet deworming will reduce environmental contamination. Public leash laws and contamination. Public leash laws and restriction of dog walking are meant to restriction of dog walking are meant to reduce fecal contamination of public reduce fecal contamination of public areas. Stray cats should be kept away areas. Stray cats should be kept away from children’s sandboxes.from children’s sandboxes.