Download gram positive eubacteria

GRAM NEGATIVE EUBACTERIA
 Spirochetes:
 The distinguishing feature of this group
o Helical shpae
o Internal flagella
 In periplasmic space
o Mostly anaerobic or microaerophilic
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Treponema pallidum
Causes syphilis
Passed sexually
Pregnancy can pass it to unborn child
Great imitator
Bacterial dormancy- in third stage
o Can travel to other organs
Penicillin is effective in killing syphilis
Three stages:
o Primary- incubation of 3 months after infection produces cankers or ulcers in the genital
region.
 Heals in 2 months
o Secondary- develops 2 to 6 months after primary where it produces rashes and fevers
 Rashes disappear after a few months
 40% will go into tertiary
o Tertiary- goes into BBB.
 Causes blindness and insanity and death.
 If untreated, 30% of individuals die from the infection
Borrelia bugdorderi
Causes lime disease
Deer tick carries the disease
White footed mouse gives tick the disease
Bulls eye rash
o Spirochete moves around the center of the bite
50% of the people who get lime disease do not recall being bitten by the tick
Some neurological disorders- Bell's palsy
Three distinct stages:
o Rashes and flu like symptoms
o Heart symptoms
 Palpitations
 Shortness of breath
 Chest pain
 Dizziness
 Fainting
o Chronic autoimmune disease
 Rheumatoid arthritis
Some proteins on this bacteria and our bodies are similar
o Triggers the production of antibodies
o Because proteins are similar, they will attack our own bodies
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SPIRILLA
Helical, curved shape
Lack internal flagella
Heterotrophs
Utilize amino acids
Aerobic respiration
In proteobacteria
o Heliobacter in epsilon subdivision
o Aquaspillium in beta subdivision
Aquaspirillum magnetoacticum
Have internal structures called magnetosomes
o Iron granules
o Allow navigation
Helicobacter pylori
Major cause of stomach ulcers
o Stomach and intestinal ulcers
Can be transmitted through saliva
Upper GI endoscopy
o Tells whether or not the stomach and esophageal linings are inflamed
o Stool test indicates presence of H. pylori
Breaks down urea to ammonia and neutralizes stomach acids
Produces a toxin that leads to ulcer formation
Toxin kills lining in the GI tract that protects against damage from the acids and causes ulcer
formation
Aerobic Rods and Cocci
Proteobacteria
Gram negative organotrophs
o Aerobic respiration
Lack the ability to ferment
Catalase
Cytochrome oxidase- present in ETS to reduce O2 to water
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Pseudomonas aeruginosa
Rods with polar flagella
Can utilize anaerobic respiration
o Utilize nitrogen as final electron acceptor
Opportunistic pathogens
Resistant to antibiotics
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Rhizobium
Rod shaped, nitrogen fixers
Form symbiotic relationship with leguminous plants (beans, peas, alfalfa)
Infects roots of plants and cause the formation of tumors called root nodules
Can fix nitrogen aerobically by utilizing leghemoglobin
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Essentially works like hemoglobin
 Any oxygen gets tied up with the molecule and keeps it away from the bacteria
 Cannot be produced without the plant and the bacteria (both HAVE to be present)
Agrobacterium tumefaciens
Crown gall disease
Invades the plant via roots and induces formation of tumors
Used in genetic engineering
o Selected genes are spliced into the Ti plasmid
o Allows for effective way of new gene introduction
Neisseria gonorrhoeae
In males it can cause discharges of pus and burning sensation during urination
In females it can often be asymptomatic and can lead to sterility
Have pili so that they can stick to UG tract
Humans are the only hosts but cannot develop an immunity to the bacteria
Facultative Anaerobic Rods:
Distinguished by shape and by ability to ultilze both fermentation and aerobic respiration
Varied group
o One major family = enterobacteria
 Comprise relatively homogenous group within the gamma proteobacteria
ENTEROBACTERIACEAE
Some are:
o E. coli
o Salmonella
o Yersina pestis
E. COLI:
One of the most common facultative anaerobe found in GI tract of humans
Extensively studied genetically
o Common to use to study genetic engineering
Some strains are pathogenic
o Cause diarrhea
o Enters body through water/food
 Spread via feces in water
Samonella typhi
Causes typhoid fever
Enters body through oral-fecal route
Produces symptoms of fever, diarrhea, and abdominal pain
o Elements of the immune system is fighting the infection.
Can kill if untreated
Often spread by means of asymptomatic carriers
Typhoid Mary:
o Most famous case of asymptomatic carrier
Several cases of typhoid broke out in NY households that were traced to Mary Mallon
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Cook/household wife
Had several jobs- spread through food
One girl dies from infection
Mary was let go and not allowed to cook
1915 there was another outbreak of typhoid fever in Manhattan
Mary Mallon took on a pseudonym as Mrs. Brown
Spread through food again
Spent 23 years on an island for isolation
Yersina pestis
Causative agent of the bubonic plague
100 million people in 6th century died
1/4 of the European population was killed
If untreated will cause 50% mortality
Can kill in 2 to 4 days after appearance of symptoms
Complex transmission to man- through rat fleas in most cases
Microbes transmitted from flea to lymph nodes
Bacteria reproduce in the lymph nodes producing enlarged areas called bubouses.
Can spread to the blood and other parts of the body
Produces subcutaneous hemorrhages that have a black appearance
Vibro cholerae
Not enteric
Part of gamma subdivision
Curved rod
Spread thru contaminated food (oral-fecal route, some asymptomatic carriers)
Produces toxin that causes severe diarrhea
Leads to water loss
Death
Treatment
Replenishing fluids
Antibiotics
Defense
Keeping water supply CLEAN!
ANAEROBIC GRAM NEGATIVE BACTERIA
Mixed phylogenically
Many in proteobacteria
Some in flavobacteria
Rods
Unable to utilize aerobic respiration
Some can use fermentation, some can use anaerobic respiration with N or S as final electron
acceptor
Can happen in wounds like gunshots where blood supply is low
Wound will reek
Bacteroides gingivalis
Bacteria lives in the mouth
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Grows in anaerobic crevases around the teeth
Believed to be on of the bacteria causing periodontal disease
Infections of supporting tissues of the teeth
Deficient Bacteria
Characterized by fact they are deficient in some way
Ricketssia
Chlamydia
Mycoplasmas
Phylogenically varied
Ricketssia = proteobacteria
Chlamydia = chlamydia
Mycoplasmas = more closely related to gram positives (cell wall)
Ricketssia:
Vary in shape
Have gram negative cell walls
Small (.6 to .8 m in size)
Obligate parasites
Missing biosynthetic intermediates- cause for being a parasite
causative agent of Rock Mountain Spotted Fever
Transmitted through wood ticks
Causes rash on wrists and ankles
Headaches and high fevers
Chlamydia:
Obligate parasites
o Lack ability to produce ATP
o Cannot produce biosynthetic intermediates without host
Cell walls gram negative
o Lack peptidoglycan
o Have gene for synthesis but lack precursors
Complex life cycle:
o Two stages:
Elementary body
0.2 to 0.4 micrometers
Physiologically inert
Resting spore
Transmission from one host to another
Reticulate body
0.5 to 1.5 micrometers
Reproduces to make more elementary bodies
Number one STD
Often asymptomatic in both males and females
Can produce symptoms similar to gonorrhea
Mother can pass to unborn child
o Can infect eyes leading to blindness
Mycoplasma pneumoniae
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Completely lacks cell wall
Pleomorophic
Small
OXYGENIC PHOTOSYNTHETIC BACTERIA
All produce energy by means of oxygenic photosynthesis
Grouped within their own phylum
Utilize chlorphyll
o Two groups
 Cyanobacteria
 Prochlorphytes
CYANOBACTERIA
Wide range of morphology
Come unicellular, multicellular, filamentous
Use chlorophyll A
Use phycobiliproteins
o Accessory pigment
o Link to red algae
Fix CO2 by means of the Calvin cycle
Degree of cell specialization that is atypical for prokaryotes
Some can have hertorcysts:
o Specialized for nitrogen fixation
o Have thick cell wall to keep O2 out
o Use cyclic photosynthesis
 Use one photosystem
 No reduced NADP
Some have akinetes:
o Thick walled
o Resting cells
o Resistant to desiccation
PROCHLOROPHYTES:
Uses both chlorophyll A and B
o Link to vascular plants
o Chloroplast precursor
<1 micrometer in size
100 meters below surface of ocean
ANOXYGENIC PHOTOSYNTHETIC BACTERIA:
Varied phylogenically
Purple in proteobacteria
Green in 2 phyla:
o Green sulfur
o Green non-sulfur
GREEN SULFUR BACTERIA:
Use bacteriochlorophyll A, C, D and E
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Site of photosynthesis are vesicles derived from the plasma membrane called chlorosomes
o Contain the harvest pigments
o Rxn center is located in the plasma membrane
GREEN NON-SULFUR BACTERIA:
Have chlorosomes
Similar bacteriochlorophyll as green sulfur bacteria
Thermophillic
o Like high temperatures
Occur as filamentous
Display gliding motion
o Differs from flagella
o Requires contact with solid surface
LITHOTROPHI GRAM NEGATIVE EUBACTERIA:
Use inorganic material as form of energy
Majority are in proteobacteria
o Can be found in nitrosipra, aquiflex and thermodesulfobacterium
o Example:
 Nitrobacter
 Thiobacillus
NITROBACTER:
o Oxidize nitrites to nitrates
o Nitrates are readily used by plants as N2 source
 Easily lost due to leaching
THIOBACILLUS:
o Colorless sulfur bacteria
o Use sulfur as an energy source
 Use variety of sulfur compounds
 S2, H2SO4
o Produce waste products which can corrode concrete and pipes
o Processing metal ores
 Leach metal from ore
GLIDING BACTERIA:
 Characterized by ability to glide
o In order to move, the bacteria they need a solid surface.
o Accomplishment varies
 Aerobic
o Utilization is different
 Lithotroph
 Organotroph
 Mixotroph
 Phyla: proteobacteria, cytophaga
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MYXOBACTERIA:
Gliding
Complex life cycle
o Begin as single cells
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End as multicellular in certain conditions
 Swarm together via gliding motion
 Form colonial organism
 Some cells form stalk, others the fruiting body, and others are considered to be
myxospores.
 Myxospores = germinate to form single celled myxobacteria to complete
the life cycle.
Gives allusion to formation of multicellular organisms
SHEATHED BACTERIA:
Filamentous forms which have tubular sheaths
High conc. of iron and or magnesium
Sheaths are for protection and adhesion to surfaces
Organotrophs
o Utilize simple organic molecules
Swarmer cell = some of the cells in the filament form this cell; motile cell with flagella; cell
germinates
BUDDING AND APPENDAGED BACTERIA:
Typically seen in yeast
Cells look asymmetrical
Proteobacteria
Characteristic of group is asymmetric shape
o Shape may be due to bacteria having an appendage that acts as an adhesion tool
o Shape may also be due to reproduction by means of budding
Planctomyces, verrucomicrobia
REVIEW:
1. Treponema pallidum:
o Gram negative
o Spirochete
o Internal flagella
 **NOTE: Peritricious flagella = flagella all around the organism
GRAM POSITIVE EUBACTERIA
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All in single phylum:
o Two subdivisions:
 High percent of GC DNA
 Low percent of GC DNA
Mycoplasmas:
o Gram positive
o Part of the low GC group
COCCI:
In low GC subdivision
Divided into 2 groups:
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Aerobic , gram positive
 Produce energy via aerobic respiration
 Some can ferment
 Catalase +
Fermentive, gram positive
 Unable to utilize aerobic respiration
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MICROCOCCUS:
Unable to ferment
Obligate aerobe
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STAPHYLOCOCCUS AUREUS:
Can ferment and use aerobic respiration
Associated with MRSA
Opportunistic pathogen
Produces variety of substances
o Coagulase: cause blood clots, allows bacteria to seal itself off from the defense factors in
the body
 Compliment- series of proteins in the blood that causes cascade to produce
signals to fight off infection and in some cases kill off the bacteria.
o Clumping factor: molecule present which allows the bacteria to stick to the surface of
the wound
o Protein A: defends bacteria from the action of antibodies and phagocytes
o  toxin: kills host cell
Can infect food and produce a toxin called staphylococcal enterotoxin A
o Heat stable
 Cooking does not kill the bacteria
Responsible for TSS
o Occurs in menstruating women using certain types of tampons
o Bacteria produces a toxin that causes an over reaction of the immune system
 Results in high fever, rash, vomiting and in some cases death.
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DEINOCOCCI:
Aerobic
In phylum Deinococci
Thermus aquaticus
o Thermophilic
o Source of TAQ polymerase that is used in PCR
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STREPTOCOCCUS PYOGENES:
Causes red blood cells to lyse
Protein F: allows bacteria to adhere to epithelial cells
Protein M: blocks action of compliment and allows it to be more resistant to phagocytes
Can produce toxins that enter the blood stream and produce scarlet fever
o Streptococcal pyrogenic enxotoxins
o Pyrogenic = trigger for immune response, chemicals that induce fever
o Endotoxin = gram negative (trigger large inflammatory response)
o Exotoxin = any other chemical bacteria produces
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Scarlet fever = systemic
o Redness of the skin
o White tongue
o Fever
Rheumatic fever
o Autoimmune disease
o Antibodies can cross react with the heart valve tissue
 Can lead to heart failure and death
LACTIC ACID BACTERIA:
Rod
Lactic acid is waste product of fermentation
Low GC subdivision
Aerotolerant anaerobes
o Lack ability to synthesize ATP by respiratory means
Important in food prodution
o Milk, yogurt, cheeses
Important in natural flora of humans
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ENDOSPORE FORMING RODS AND COCCI:
In Low GC subdivision
Two groups:
o Aerobic
 Respiration
o Anaerobic
 Fermentation
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AEROBIC
Bacillus anthracis
Has a capsule
Produces variety of endotoxins
Usually a disease of domestic and wild herbivores
Cutaneous:
o Most common human infection
o Enters through abrasion to skin
o Blister forms at site of entry
 Develops into blackened crater
o Most cases will heal
o 10-20% becomes fatal
Respiratory:
o Less common
o More dangerous
o Begins with mild respiratory symptoms
o Enters into blood stream
 At this point almost no patients survive
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ANAEROBIC:
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Clostridium botulinum
Bacteria produces a food borne disease
Occurs in canned food
Produces damage because of a neurotoxin produced by the bacteria
The neurotoxin is heat sensitive
Boiling food can kill them off
Initial symptoms include weakness, dizziness, blurring of vision
o Occurs 18-36 hours after consumption
Blocks release of ACH and causes paralysis
Clostridium perfingens
Infects deep puncture wounds like gunshot wounds
Spores are common in the soil but only rarely develop into an infection because of the
anaerobic conditions (dead tissue = no O2) which are needed for growth
o Gas gangrene develops
Distinguished by the appearance of gas which produces gas bubbles under the skin
Bacteria produces -toxin which causes the tissue damage associated with the gas gangrene
Once infection starts, rapidly spreads due to production of gas
o More anaerobic conditions for the bacteria to survive in and kill off other bacteria which
inhabit the body.
o Especially happens in the muscles
 Muscle fibers
Produces several enzymes that aide in spreado Colagenase
o Hyaluronidase
To fully kill off the infection, amputation is often necessary
Other treatments include antibiotics and placement in an oxygen chamber.
Clostridium tetani
Causative agent of Tetanus
Spores are common in soil
o Contaminates skin, clothing, wounds
Characterized by sustained, painful and uncontrollable cramp like muscle spasms
Begins with lock jaw
Breathing can become labored
Almost unbearable pain occurs and death
Harmful effects are due to toxin called tetanospasmin
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Helobacteria
Anoxygenic photosynthesis and bacteriochlorophyll
o Bacteriocholorphyll g
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CORYNEFORM GROUP
Variation in cell shape
HIGH GC
Group includes :
o Corynebacterium
o Arthrobacterium
o
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Mycobacterium
 Nasty disease
Corynebacterium diptheriae
Irregular club shape
v-shaped arrangements
Aerobic/fermentation
Causes diptheria
o Sore throat
o Fever
o Fatigue
o Neck swells
o Whitish grey membrane forms on the tonsils and throat
o Can result in heart and kidney failure
Damage is due to diptheria toxin which inhibits 80s ribosomes
Toxin is large protein and only certain tissues such as the heart and kidney can absorb it
Treatment involves immunization and anti-toxins
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Arthrobacteria
Commonly found in soil
Cell shape changes with age
o Log phase (active growth) are rods
o Stationary phase (resting) are cocci
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Mycobacterium
Pleomorphic
Branch and are filamentous
o Rods that branch off
Typically contain unique lipids called mycolic acids
o Lipids make them resistant to a large number of antibiotics and phagocytosis
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Mycobacterium tuberculosis
Causes TB
Airborne transmission
Bacteria in lungs are phagocytized by the white blood cells, but cannot be destroyed because of
mycolic acid
o Remain present in white blood cells
90% of the infections do not result in illness
o Bacteria are isolated by macrophages in nodules called tubercles
o Tubercles are inflammatory lesions which contain WBC containing the mycobacteria
tuberculosis
If bacteria persist, the tubercles can become calcified and bacteria are then released and can
destroy the lung tissue because of hypersensitivity
GRAM POSITIVE FILAMENTOUS:
Resemble fungi
In High GC subdivision
Tendency to form long branching filaments similar to hyphae and produce spores.
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Streptomyces- important because of the antibiotics that they produce
o Streptomycin, erythromycin, chloramphenicol and tetracycline = antibiotics
FUNGI
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CHARACTERISTICS:
Eukaryotic
o 80s ribosomes
o Nucleus
o Cell walls are composed of phospholipids and carbohydrates
Saprophytes
o Fungi break down dead organic material
Absorptive nutrition
o Digest extra-cellularly and absorb the nutrients
Cell wall
Spores
Multinucleated
MORPHOLOGY:
Occur in 2 forms:
o Yeast
 Single celled
o Hyphae
 Long, branched, threadlike structures
 Can occur in 2 forms:
 Coenocytic
 Multinucleated
 Lack cross walls
 Septate
 Have cross walls
 Are considered to be multinucleated due to pores connecting the cells
Arrangements:
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 Mycelium = mat of hyphae
 Fleshy = highly organized into threads which make up the body of the fungus
DIMORPHIC FUNGI:
Mycelium outside the body, yeast inside the body
PHYLOGENY OF FUNGI:
Based upon rRNA analysis and morphology of mitochondria
3 distinct groups:
o True fungi (Eumycota)
o Water molds (Oomycota)
o Slime molds
Slime molds:
Lack cell walls in vegetative state
Look a lot like protozoans
rRNA and mitochondria- group is closer to protozoa and algae than fungi
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2 major groups:
o Cellular
 Resemble protozoan amoeba
 Have complex life cycle in which they start off as uninucleated amoeba
 Cell are starved and amoeba swarm to make a multicellular fruiting body
 Fruiting body forms stalk which is rigid due to cellulose
 Other cells form walls and become spores
 Spores germinate into amoeboid vegetative cells
 Saptophytes
 Produce cell walls in the multicellular stage
 Reproduce via spores
o Acellular
 Life cycle begins with multinucleated (diploid) plasmodium (lacks cell wall)
 Plasmodium can form fruiting body
 Produces spores via meiosis (spores have cell walls)
 Spores germinated into gametes which fuse to form the diploid gamete
 Decomposer
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True Fungi:
Have mitochondria
Lamellar cristae
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Chytrids:
Primitive
Lower fungi
Aquatic fungi
Reproduce with motile flagellated cells
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Zygomycetes:
Lower fungi
Reproduce by means of zygospores
Sexual reproduction occurs when haploid hyphae of compatible mating type fuse and form a
zygospore
Zygospore undergoes meiosis to produce a haploid zygospore
Haploid germinates into haploid hyphae to complete the cycle
Rhizopus:
Zygomycete
Commonly called black bread mold
o Food spoiler
HIGHER FUNGI
Remaining true fungi are eumycota
o Ascomycetes and basidomycetes
Characterized by:
o Hyphae with walls
o Asexual spores
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Ascomycetes:
Reproduce sexually by means of ascospores
During sexual reproduction hyphal filaments are produced that are dikaryotic ascogoneus hyphae
Within one of the hyphae:
o Two nuclei fuse to form a diploid zygote
o Called asci
 Zygote under goes meiosis to form ascospores
 Germinate to form haploid hyphae to complete the life cycle
Some grow as mycelium
Some grow as fleshy fungi called truffles
Some as yeast
o Sacchromyces cervisiae
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Sacchromyces cerevisiae
Important in food production
Bread, beer, wine are produced by this fungi
Producing CO2 to cause the bread to rise
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Penicillium
Food production
Ripens cheese
Antibiotic source
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Candida
Dimorphic and produce disease
o Once spores enter the body they grow as yeast
Can occur in different parts of the body
o Skin- swelling, scaling, irritation
o Female reproductive tract and mouth- more commonly called yeast infection
 Thrush forms
Can be more problematic
o Can be systemic via the blood stream
o Can have issues referring to myocardial, and renal systems
Part of natural flora
o Not usually a problem unless the person has a weakened immune system
 Age
 Young and old people
 Immune response is lowered at these states
Histoplasma:
Causative agent of histoplasmosis
Symptoms similar to flu
Associated with bird and bat droppings
o Breathe in the spores
o Droppings are great environment for fungal growth
25% of cases show more severe systems
o Systemic
o Lead to chronic problems like:
 Pneumonia
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Muscle aches
Fevers
Headaches
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Dimorphic
Airborne
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Microsporum
Athlete's foot
Moist surface areas of the body
o Jock itch
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BASIDOMYCETES:
Produces basidospores
Haploid hyphae of compatible mating type fuse and form dikaryotic hyphae
o Gives rise to a fruiting body
o Mushrooms fall into this group
Within specialized sexual reproductive structure
o Fuse nuclei
o Called basidia cells
o Diploid not primary stage
Agaricus
Edible mushrooms
Cyptococcus neoformans:
Dimorphic
Airborne
Associated with pigeon droppings
Causes cough and fever
Self-limiting
o Age
o Poor immune system
 AIDS patients
 Top four life threatening infections
o Can cross over into the blood and cause meningitis
Has a yeast capsule
o Inhibits phagocytosis
PROTOZOANS
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Classifications:
Unicellular
Heterotrophs
Lack cell wall
Not like fungi
Motile
o All at some point in their life cycle, but not necessarily all the time
Amoeba
o Pseudopods
Flagellates
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o Flagella
Ciliates
o Cilia
Sporozoa
o Mostly non motile
o Only during sexual reproduction
Evolved several times within eukaryotic evolution
AMOEBA
Pseudopods
Some are enclosed in hard shells
Important geologically because deposits of shell are left over
o Chalk
o Limestone
Entamoeba histolytica
o Cause dysentery
o Severe infections can produce blood and mucous in the stool
o Enters via oral-fecal transmission
 Cysts
 Have cell walls of chitin
 With stands stomach acids
o Best defense is effective water sanitiation
o Completely lack mitochondria
o rRNA links this group with slime molds
FLAGELLATES
Characterization is by movement of means of flagella
Some are important pathogens
o Giardia lamblia
o Trichomonas vaginalis
o Trypanosoma gambinese
o Leishmania donovani
Giardia lamblia
o Most commonly transmitted water borne disease in the US
o Normal chlorination is ineffective against it
 Kept out of the water supply by means of filters
o Enters via oral-fecal route (cysts)
o Symptoms
 Gas
 Nausea
 Explosive diarrhea
o Can become chronic
o Lacks mitochondria
Trichomonas vaginalis
o STD
o Lacks cyst
o Males are asymptomatic
o Females can cause itching and burning
o
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Lacks mitochondria
KINETOPLASTID
Primitive mitochondria
Trypananosoma gambiense
Infection of the blood
Reservoir for these are tsetse fly
o Fly bites you
Parasite enters blood stream and lymph
Infection invades CNS and causes nerve cells to die
 personality
o Lack of interest
o Mental retardation
o Slowness
o Lethargy
Leishmania tropica
Infection of blood
Commonly in canines and rodents
Cross into humans via insect bite
o Sand flies
Enters through skin
Englufed by macrophages upon entry and inside the macrophages form non motile cells which
destroy host cells
Ulcers from frequently on face and ears
Healing occurs producing scaring and a permanent immunity
CILLIATES
Locomotion via cilia
Have 2 nuclei
o One has many copies of genome
 For transcription
 macronucleus
 Makes proteins from here
o One is for reproduction only
 Micronucleus
Tubular cristae
o Closely related to sporozoa and dinoflagellates
Balantidium coli
Can occur in digestive tract
Largest microbe that can infect humans
Parasite of the colon
Oral fecal transmission
Not dangerouso Bloody diarrhea possible
SPOROZOA
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Not motile all their life
o Reproduction only
 Male gametes only
Spore former
Based upon rRNA and mitochondrial cristae they are closely related to ciliates and dinoflagellates
ALL PARASITIC
Complex life cyle
o Involves 2 or more hosts
 Intermediate host
 Immature form reproduces asexually
 Definite host
 Replicates sexually
 Mature form
Plasmodium
Most important parasite
Causes malaria
Humans are intermediate hosts
Enters blood stream via mosquito bite
Plasmodium enters into human body as haploid sporozite
o Enter the liver
o Reproduce asexually
 Merozites
Merozites released into the liver and infect red blood cells
o RBC lyse and infect more cells
RBC stage is cyclic (repeats every 48 to 72 hours)
o Release causes attacks of chills and fever
Some RBCs do not rupture and the mosquito bites the infected person and spreads the disease
In mosquito
o Forms diploid ookinite
o Ookinite undergoes meiosis and produces haploid sporozites
MALARIA
Considered to be a pandemic
500 million/year are infected, 1-2 million die.
Chloroquine works by attaching a food vacuole in the plasmodium
Plasmodium digests hemoglobin
o Heme is toxic to microbes
o Converts heme to hemozoin which is insoluble and non toxic
DDT is limited because of environmental impact
Chlorquine limited- resistance.
VIRUSES
 Simple structure
o Nucleic acids surrounded by protein coat
 Obligate parasite
 No metabolism of their own
 Small
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.02 to .20 micrometers
VIRAL GENOMES
 All contain nucleic acids
 Classified on basis of the type and usage of the nucleic acids they possess
o Transcription and replication
 DNA and RNA viruses
o Single stranded vs. double stranded
 Single stranded RNA can be divided further
 +single stranded
 -single stranded
 Difference is how RNA is utilizes transcription
 If it is + goes directly to the host ribosome and begins making proteins
 If it is - goes directly to making the complimentary RNA to transcribe to make
the proteins within the host.
Retroviruses
 RNA to DNA
 Segmented genome
o Enhance the amount of the genetic diversity produced by multiple infections of a host
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CAPSIDS
All have capsids
Protein coat
Protein segments are called capsomeres
Display 3 types of capsids
o Polyhedral
 Many sided
 Spherical shape
o Helical
 Cylindrical
 Hollow
o Complex
 Neither symmetry
ACCESSORY STRUCTURES
 Bacteriophages
o Tail fibers
 Important in attachment to the surface of bacteria
o Contractile sheath
 Inject DNA into bacteria
o Envelope
 Lipoprotein layer that surrounds capsid
 Soap bubble analogy
 Envelope fuses with our envelope
 Makes viruses more susceptible
 HIV has envelope
 Easy to kill out of the host, difficult to kill in the host
o Spikes
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Adhesion factor
VIRAL ENZYMES
 Contain enzymes for infection process
 Some RNA viruses contain RNA dependent RNA pol
 Retroviruses contain reverse transcriptase
VIRAL LIFE CYCLE
 Attachment
o Via tail fibers or spikes
o Some viruses are naked
 Penetration
o Some cases the virus enters via phagocytosis
o Can enter through pre-existing spores
 Early proteins
o Viral genome is used to produce proteins needed for viral replication
 Late proteins
o Structural proteins
o For capsid and accessory structures
 Assembly
o Structural proteins assemble around the viral DNA to make new viruses
 Release
o Some cases the virus leaves via lysis
o Enveloped viruses Release occurs via budding
o Other cases release occurs by means of pores
 Pre existing or produced by viral enzymes
CLASSIFICATION OF VIRUSES
 Groups:
o +single stranded RNA
o -single stranded RNA
o Double stranded RNA
o Double stranded DNA
o Single stranded DNA
o Retroviruses (RNA -> DNA)
 Major differences
o Type of nucleic acid
o Single or double stranded
o How they use the information to make more viruses
+SINGLE STRANDED RNA VIRUSES
 Genome = single stranded RNA
 RNA = mRNA as well
 No RNA dependent RNA pol for transcription
POLIO VIRUS
 Naked polyhedral capsid
 Transmitted via throat and nasal discharges and enters body orally
 Initially infects the throat or digestive tract
o Mostly controlled by immune system
 Few cases can spread from initial site to nervous system
o Can cause paralysis
o Very specific- will kill motor neurons
 Receptor site is motor neurons (only place that it can attach because it has no
spikes)
Will lyse the motor neurons causing the paralysis
Mainly affected industrial countries
Less developed countries everyone was exposed to the virus
o Developed immune resistance
o Infants exposed to virus but antibodies provided by mother to prevent serious infection
Industrialized advanced sanitation methods kept virus out of water avoiding exposure and when
exposed would get sick
Today it is controlled via immunization
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CORONAVIRUS
 Has glycoprotein spikes
 Enveloped and contains club shaped glycoprotein spikes that cause the virus to have the
appearance of a crown
 Causative agent of SARS
o 8100 people became sick in 2003
o 774 died
o Begins with high fever and headaches
o 2-7 days later develop a dry cough
 Most develop pneumonia
o Future outbreaks can potentially occur
o Don't know what the animal reservoir is
-SINGLE STRANDED RNA VIRUSES
 Viral genome is used as a template to synthesize the mRNA needed to produce viral proteins
needed to produce the new virus
 Carries a copy of the enzyme RNA dependent RNA pol
 Enzyme used to transcribe two classes of RNA
o mRNA
o +complimentary strand that is a copy of the entire viral genome
 Full length +strand are used as templates for the -strand
ORTHOMYXOVIRUSES
Causative agent of influenza
Helical capsid
Has envelope
Segmented genome
o All different parts to it
o More than one RNA molecule present
o Allows for different strands to form
1918.
Flu pandemic
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Took 3x as many lives as WWI
Flu viruses come from the digestive tracts of birds
Once in a while the bird flu changes and infects other hosts
Possible that the species barrier was crossed and infected humans
 Bird flu has not been able to pass from human to human
Hemagglutinin antigen (H)
o Uses it to adhere to surface of host cells
o Can cause clumping of RBC
o Target is not the RBC, cells of the respiratory tract
o Both types of cells have the target molecule that H binds to (salic acid)
o RBC is conveinitent way to test
Neuramidnidase
o Breaks down mucous and other glycoproteins which aide in spread and release of the
virus
Both types of spikes are involved in triggering the immune response
Segmented genome (8 segments) that allows it to produce new strains via ANITGENIC SHIFTS
Antigenic shift
o Recombination occurs between strains of the virus occurring in different animal hosts
Type A virus
o Occurs in several hosts and is associated with the more severe forms of the flu
o Can be further subdivided into 15 subtypes
 15 H spikes
 9 N spikes
o New strains appear when avian virus mixes with the human
 Can occur in pigs which can be infected with both types
Pandemics occur when the virus
o Picks up spikes you have not been exposed to before
o Still maintains the ability to rapidly spread from human to human
AVIAN FLU
 H5 N1
 Seems not to have mutated into a form that can spread from human to human
SWINE FLU
H1N1
Thought to have originated in Mexico
Genetic mixture of viruses from pigs, humans, and birds
Called swine flu because the overall structure of the virus is of the type that effects pigs
Swine flu found in Mexico and the 1918 Spanish Flu viruses are of the H1N1 subtype
o About 1% lethality which is considered to be normal for an influenza virus
 Spanish flu began with a normal infection
o Began during WWI
o Massive amounts of people who were in war time, easier to spread to weakened immune
systems
o Passed from person to person via a mutation
 Seems to be attacking individuals that are younger
o Strength of the immune system is not protecting people
 Antiviral drugs
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Tamaflu
 Goes after the N
 Blocks it from functioning
Rabies Virus
Helical
Bullet shaped
Rhabdovirus
Envelope
o Disrupted by soap
Nonsegmented genome
Infection caused by animal bite
Virus incubates in muscle cells and then infects neurons associated with muscles and then goes
into CNS
Long incubation
100% lethal
o If untreated will infect CNS
Early symptoms are headache, fever, nausea
Increased salivation
o Foaming of the mouth
o Makes sense because spread via oral route of transmission
50% of cases develop hydrophobia
o Painful spasms of the throat and respiratory muscles provoked by swallowing or seeing
liquids
Double Stranded RNA Viruses
 Naked
 Polyhedral capsid
 Segmented
o 10-12 linear dsRNA molecules
 Packaged with RNA dependent RNA pol
o Used for NA replication and transcription
Colorado Tick Fever
 Causative agent is orbivirus
 Transmitted via tick bite
 High fever, severe headache
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DOUBLE STRANDED DNA VIRUSES
Replicate by entering into the host (phagocytosis)
Enters into nucleus by budding into nuclear membrane
Viral DNA replicated and genes are transcribed to produce viral proteins
Proteins synthesized in cytoplasm
o Transported into the nucleus for assembly
SMALL POX
 Largest virus which infects humans
o .2 micrometers
 Polyhedral capsid
 Envelope
o Composed of proteins
 Uncoating of virus requires host to synthesize an enzyme coded for by the virus
 Replication and transcription within the cytoplasm is an unusual feature for a dsDNA virus
o Most replicate nucleic acids within the nucleus of the host
 Has own RNA pol
 Highly contagious
 Respiratory route
 12 day incubation
 Initally produces high fever and fatigue
 No effective treatment
o Vaccine
 30% fatality
 Mostly eliminated due to vaccines
 Oldest recorded viral infection
o 1157 BC
 Spanish brought the disease to America, killing natives
o 90% fatality
HERPES SIMPLEX VIRUS 1
 Polyhedral with envelope
 50% population infected
 Usually asymptomatic
o Can produce cold sores
 Can remain dormant
o Latent
 Infects nerve cells
HSV-2
 Genital herpes
 Blisters and lesions on reproductive organs
 Can be transmitted when symptoms don't show
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Single Strand DNA Virus
Slapped cheek syndrome
Respiratory transmission
Rash on face (cheeks)
Can be dangerous if infects pregnant woman
RETROVIRUSES!
 Enveloped
 Polyhedral capsid
 ssRNA
o Infects host
o RNA converted to DNA via reverse transcriptase
HIV
 Causative agent of AIDS
 Transmitted sexually, or via contaminated needles or serum
 Has latent period
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DEFENSE SYSTEM
2 lines of defenses
o Non-specific
 General defense
 Not specific to any microbe
 On all the time
o Immune system
 Must be activated
 Specific
 Targets particular microbes and kills them
NON SPECIFIC
Lacks specificity
Utilizes physical barriers
Biological barriers
o Blood substances which can be mobilized to the site of infection
 Clotting, white blood cells
PHYSICIAL BARRIERS
 Defend external regions of the body
o Skin
 Tightly packed epithelial cells which act as barrier
 Dryness inhibits growth of microbes
 Salt
 Lysozyme- break down peptidoglycan
 Organic acids produced by gram positive bacteria breaking down lipids
 Difficult adhesion
o Respiratory system
 Lined with mucous
 Traps microbes
 Contains lysozyme, lactoferrin, secreted antibodies
 Lactoferrin prevents microbes from being able to use Fe
 Cilia
 Nasal cavity
 Pharynx and mouth
 Constant passage of air makes for difficult adhesion
o Digestive system
o Urogentital tract
 Natural flora
o Help to protect against the bad stuff
INTRO TO IMMUNOLOGY
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Antibodies:
Proteins are made by B cells
They are composed of 2 types of protein chains
o Y shaped
o Light
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Heavy
 Linked by disulfide bonds
Each chain has a variable region and a constant region
o Variable region that determines the specificity
Can respond to an infection of polio by making antibodies against the virus
Antibodies produce will only attack the specific virus and would not be effective against another
virus
Mechanisms of Antibodies:
How do they attack pathogens?
o Defend against microbes
 Neutralization
 Block the sites on viruses/bacteria that allow them to infect cells
 Works on proteins too
 Opsionization
 Binding to bacteria
 Make it easier for phagocytes to destroy the infection
 C3B protein
 Phagocyte responds to the constant region
 Agglutination
 Causes clumping of bacteria
 Brings them together and makes it easier to get a lot of them for the phagocytes
to engulf and destroy
 Activates
 Inflammatory response
 Basophils increase blood flow to an area
 Mast cells
 Antibodies attach to the cells and histamine is released and the inflammation
occurs
 Constant region bound to receptors
 Determines strength of signal
 Activates compliment
 Bind to surface
 Compliment protein binds to constant region
 Binding causes attraction of compliment proteins
 Triggers inflammation
 Coat cells to allow natural killer cells to attach and kill cells infected with cancer or
viruses
 Can make phagocytosis easier
CLASSES OF ANTIBODIES:
Can produce 5 types of antibodies
o IgA
o IgG
o IgM
o IgD
o IgE
All specialized in their own way! :)
o Depending on their heavy (constant) chain
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IgA
Utilizes alpha heavy chain
o Dimer
Found in secretions (mucous, milk, saliva)
Important in terms of protecting external surfaces
Activate complements
o WEAK ACTIVATION
Helps in opsionization
4 binding places
o Good for glutination
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IgM
Mu heavy chain
First antibody to appear
o Developmentally
o Immune response
Good at activating complement
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IgG
Gamma heavy chain
Most abundant
Small enough to cross the placenta and protect the fetus
Activates complement
Effective opsionization
Appears after production of IgM
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IgD
Delta heavy chain
On surface of B cells
Activator of the immune response
Site of initial attachment to antigen
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IgE
Epsilon heavy chain
Binds to mast cells and basophils to cause inflammatory response
Most associated with allergies
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FOR EXAM: know structure, functions, and differences of antibody classes
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HYPERSOMATIC MUTATION
Gene for the heavy chain consists of minigene regions called V,D, and J
Each minigene codes for a different region of the heavy chain
Before it maures the VDJ splicing occurs in which one out of 200 V minigenes, one out of 3 D and
one out of 4 J are joined together to make the functional gene
A similar process occurs for the light chain
o Each B cell as it matures makes a different antibody
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Immune system can respond to well over a million antigens because it produces well over a million
genetically different B cells.
B CELL DEVELOPMENT
If any B cell produces antibodies that can attach antigens in our own tissue, those cells are
destroyed
If B cell attaches to an antigen, memory cells created and reproduce for future attacks.
T CELLS
Two types
o Helper cells
 Activate immune response
 Comes into contact with a macrophage that has a destroyed bacteria
 T helper cell detects the destroyed antigen and triggers the response
 Needs two signals
 Major histocompatibility protein (self)
 Proteins which occur on the surface always
 Uses its CD4 protein to recognize class II MHC
 Class II = not found in all cells, only in B cells and macrophages
 B cells and macrophages are only activators
 T cell receptor
 Detects antigen
 Has hypersomatic mutation
 Releases interleukins
 Stimulates production of T cells
 Also activates macrophages
o Cytotoxic cells
 Specific in that they have T cell receptor and will only attack those cells that have
antigens complimentary to it
 Attack cells that are infected with viruses
 Important in killing cancer cells
 2 signals
 Foreign antigen
 CD8
 Class I MHC
 Releases perforin and CD95
 Pores in cell membrane
 Self-destruction
NATURAL KILLER CELLS
Attack cells that lack class I MHC
Cancer cells and cells with viruses have altered structure of the class I MHC
o Will attack