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183 Cards in this Set

  • Front
  • Back
What are the factors responsible for emergence of a disease
Human demographics and behavior
• Technology and industry
• Economic development and land use
• International travel and commerce
• Microbial adaptation and change
• Breakdown of public health measures
• Abnormal natural occurrences
What fraction of the population died during the plague?
What was the etiological agent of Medieval Black Death?
Yersinia pestis
What was the problem with quarantine during the plague?
the rats could come and go as they pleased. Even rats aboard docked quarantined ships had easy egress, because they could climb down the mooring ropes and onto the docks.
What did Van Leewenhoek do?
he did the microscope
What was the theory of Spontaneous Generation?
• First put forward by Aristotle (384 - 322 B.C.) and held sway for almost 1900 years!
• For example: Mice could arise from grain left to sit in a dark place
What did REdi do?
Didn't buy sponataneous generation so did the meat in the beaker thing
How did Louis's goes neck work?
Dust and microorganisms were trapped in the bend and so the liquid remains sterile for years
What did Koch do?
Credited with demonstrating the first direct link between a single microbe and a single disease – Tuberculosis
Set up Koch's postulate
What did Hesse do?
Introduces the use of agar
What was the Golden Age of Microbiology?
Applied principles and methods elucidated by Koch and Pasteur
Identified the causative agent of many important diseases including TB, plague, cholera, tetanus, influenza
What did Semmelweis propose?
wash your hands you fucking morons
What did Jenner do?
the first vaccine against small pox!!
What are non communicable diseases?
Genetic Diseases (e.g., PKU, Tay-Sachs, schizophrenia, some cancers)
Nutritional Deficiencies (e.g., scurvy, beriberi)
What are communicable diseases?
Transmissible Spongiform Encephalopathies or Prion Diseases (e.g., scrapie, Creutzfeld-Jacob Disease, chronic wasting disease)
Interactions between a host and a pathogen (i.e., flu, encephalitis, malaria, ringworms, some cancers)
What are genetic diseases?
Genetic Diseases
(e.g., PKU, Tay-Sachs, schizophrenia, some cancers)
Epidemiological Framework:
Mendelian & Population Genetics
Treatment Options:
Genetic and Phenotypic Therapies
What are nutritional deficiencies?
Nutritional Deficiencies
(e.g., scurvy, beriberi, dehydration)
Epidemiological Framework:
Individual and Population Nutrition
Treatment Options:
Diet Alterations
What are spongiform diseases?
Transmissible Spongiform Encephalopathies
or Prion Diseases
(e.g., scrapie, Creutzfeld-Jacob Disease, chronic wasting disease)
Epidemiological Framework:
Treatment Options:
Transmission Prevention
What are infectious diseases?
Infectious Diseases
or Host-pathogen or Host-parasite Interactions
(e.g., flu, encephalitis, malaria, ringworms, some cancers)
Epidemiological Framework:
Host-pathogen interactions
Treatment Options:
Population control both within and between hosts
what type of interactins are infectious diseases?
Who is the father or modern medicine?
Believed illness caused by physical factors and not by superstitions, evil spirits or disfavor of the gods.
Based medical practice on observations and the study of the human body.
Believed rest, exercise, good diet, fresh air and cleanliness cured disease.
Developed the Oath of Medical Ethics
Made detailed observations of disease outbreaks and spread.
First noted that tainted water was often associated with disease outbreaks.
Recognized that different diseases were associated with various climatic times (e.g., “hot” vs. “cold” diseases).
Recognized that some diseases were associated with particular ecological environments (e.g., malaria and yellow fever most common in swampy areas).
What did James Lind do?
Conducted experiments on causes of scurvy.
Scurvy was a prevalent disease of sailors on extended sea voyages
Symptoms include severe pain, irritability, listlessness, internal and external hemorrhaging, brittle bones, swollen gums & loose teeth.
How did Lind do his experiments>
Divided 12 scurvy’ed men on HMS Salisbury into 6 groups of 2.
Put each group on the normal sailor’s diet (which was deplorable), but each group got different supplements (e.g., vinegar, garlic, mustard, horseradish).
One group’s supplement was 2 oranges and 1 lemon each day.
What is scurvy caused by?
Scurvy is caused by Vitamin C deficiency
What did Koch do with Anthrax?
Infected some mice with the bacillus from the spleens of farm animals that had died of anthrax. Used splinters of wood to do innoculations.
Infected other mice with blood from spleens of uninfected farm animals.
Mice infected from anthrax all died, while none infected from healthy farm animals died.
This confirmed work of others that exposure to anthrax-killed animals was the cause of the infection.
How does Koch's postulate work?
The organism must be found in all animals suffering from the disease.
The organism must be isolated from the diseased animal and grown in pure culture.
The cultured organism should cause the disease when introduced into healthy animals.
The organism must be reisolated from the experimentally infected animal.
What did Pasteur do with anthrax?
Noted that some cows were more severely affected than others.
Decided to do an experiment in which he infected two cows with a strong dose of the anthrax bacillus (this followed Koch’s work).
Neither cow developed anthrax!!
He came to find that both cows had previously had anthrax and recovered.
Decided that if some way could be found to infect animals with a mild attack, they could be protected from the disease.
After much trial and error, developed a method to heat-treat bacteria that would subsequently give cows only a mild case of anthrax.
What are the thre main approaches to the modern practice of epidemiolog?
Experimental Studies

Statistical Studies of Populations

Modeling Studies of Theoretical Species
What is prevalance?
Prevalence is the percent of a specific population with the disease.
Can epidemiology be predictive?
Yes! It's the stupid model!
What is equilibrium?
We can ask whether this population will settle to some point where the abundances of the three types of individuals will stop changing.
How do we find the equilibrium?
Set each equation equal to 0 and simplify
What can the presence fo disease do to a population?
However, the presence of disease can “regulate” the population (i.e., keep it from zooming off to infinity).
What do epidemiologist investigate in the infectious disease cycle?
Characteristics of the infectious organism
Source and or reservior of the infectious organism
Mode of transmission
Susceptibility of the host
Exit mechanisms
how many pathogen species are there that can infect humans?
538 bacteria
317 fungi
287 helminths
208 viruses
57 protozoa
What are prokaryotes?
Lacking a nucleus, mitochondria, spliceosomal introns and spliceosomes
Possessing transcriptionally coupled translation
What differebces are often important for understanding the mechanisms of action of chemotherapeutic agents
1. Chromosome(s)
2. Organelles (mitochondria & other membrane bound structures)
3. Mechanism of cellular movement
4. Cell wall
Compare Eucaryotic and procaryotic chromosomes?
Eucaryotic: Each cell contains a number of different chromosomes contained Within the Nuclear Membrane. Mitosis occurs.

Procaryotic: Each cell contains one circular chromosome. Not bound by a nuclear membrane. The mechanism of chromosome segregation during division does not involve mitosis.
Compare Eucaryotic and procaryotic organelles?
Eucaryotic: Mitochondrion- contains the oxidative enzymes and carries out oxidative phosphorylation. Eucaryotic cells also contain other membrane-bound structures, such as vacuoles, peroxisomes, etc.

Procaryotic: Cells contain no mitochondria. Oxidative enzymes are associated with cytoplasmic membrane of cell. Oxidative phosphorylation is associated with the cytoplasmic membrane.
compare motility in eucaryotic and procaryotic cells?
Eucaryotic cell: Movement may be accomplished by cytoplasmic streaming (amoeboid movement) or by contraction of flagella or cillia (comprised of longitudinal fibers and has a membrane coat).

Procaryotic cell: There is no cytoplasmic streaming or amoeboid movement. Some bacterial cells also have flagella. However, the structure of bacterial flagella is very different (a fibrous protein of molecular dimensions, composed of repeating subunits).
Compare the cell walls and eucaryotic and procaryotics cells?
Eucaryotic cell:
plants and green algae - polysaccharide cellulose (polymer of glucose).
fungi the cell wall - chitin (polymer of N-acetyl glucosamine).

Procaryotic cell: In most procaryotes, the cell wall is composed of a peptidoglycan polymer, containing muramic acid (derivative of acetyl glucosamine), D-amino acids and other unusual amino acids as unique components, which are not found in Eucaryotic cells.
How is the cell wall important for antibiotics?
The ability of an antibiotic such as penicillin to kill without harming animal cells was explained when it was discovered that penicillin interfered with the formation of this peptidoglycan
What is the evidence for the difference between Archaea an Bacteria?
Cell walls
Cell membranes
2/3 of genes in various seqeunced archaebacterial genomes differ from eubacteria
What are extremophiles?
So named because thought to be similar to bacteria that must have lived on primitive earth
What are stromatolites?
“At right is a layered stromatolite, produced by the activity of ancient cyanobacteria. The layers were produced as calcium carbonate precipitated over the growing mat of bacterial filaments; photosynthesis in the bacteria depleted carbon dioxide in the surrounding water, initiating the precipitation. The minerals, along with grains of sediment precipitating from the water, were then trapped within the sticky layer of mucilage that surrounds the bacterial colonies, which then continued to grow upwards through the sediment to form a new layer. As this process occured over and over again, the layers of sediment were created. This process still occurs today.”
What is the deal with sirface area to cell volume ratio?
The ratio of surface area to cell volume is VERY high in comparison to a larger organism of a similar shape.
A large surface area for the entry of nutrients to a small cell volume - contributes to the ability of bacteria to grow rapidly
What is coccus?
Sperical form or "coccus”
From Greek meaning “berry”
What is bacillus
Rod shaped or "bacillus”
From Greek meaning “little walking stick
What is spiral?
Curved rod or spiral shape
From Greek meaning “little coil
How are bacterial cells arrnaged
Successive divisions of cocci along the same axis will result in a chain of cocci as in the Streptococci.

b) If successive divisions of cocci can occur in any direction, irregular clusters will result, as found in the Staphylococci.
How does the plasma membrane differ in archaea?
They have Lipid monolayer
Compare tghe linkage, structure, and sterols on the bacterial, archaeal, and eukaryotic membranes
Bacteria and Euk have ester bonds whereas Archaea have ether bonds
Archaea have a lipid monolayer, and only Euk have sterols
What are sterols?
rigid planar molecules, stabilize membrane,
can be 5-25% of total lipids. Example - cholesterol
What are the function of the cytoplasmic mebrane?
1. Membrane contains oxidative enzymes (cytochromes, quinones,
ATPase) and resembles inner membrane of mitochondria, both in structure and function.
2. Membrane also contains enzymes which function in external
cell wall synthesis.
3. Membrane must have ability to pump in nutrients from dilute external media and thus contains selective transport systems for specific sugars, amino acids, metals, etc.
4. Membrane contains mechanisms for secreting toxins and certain enzymes into the extracellular medium.
What does the cell wall do?
1. Gives shape and rigidity to cells

2. Prevents cell lysis by osmotic shock Bacteria live in dilute environments, but there cytoplasm has many dissolved solutes. Result is turgor pressure of ~2 atm (about the same as a automobile tire).The membrane alone would burst under these conditions without the cell wall.
What else does the cell wall do?
1. Site of antibiotic action
i.e. The enzyme lysozyme splits the glycosidic bond between N-acetyl glucosamine and muramic acid - antibacterial.
2. Composed of subunits found nowhere else in nature
i.e. Short peptide consisting of 4 aa linked to the lactic acid residue. Some aa are in the uncommon D-configuration.
3. The cell wall can produce symptoms of disease
i.e. act as a toxin
4. Differences in cell wall composition affects staining properties.
i.e. Gram stain
What is peptidoglycan?
All bacteria (with one exception) have walls that contain a unique polymer of N-acetyl glucosamine (NAG) linked to muramic acid by a glycosidic bond.
3. This polymer is usually called "peptidoglycan”or "mucopeptide" because of its peptide & sugar components.
4. "Cross-linking" occurs by bonding between amino acids side chains. Penicillin blocks cross-linking.
What bacteria do not have cells walls?
What does not have peptidoglycan?
What do gram + bacertia have?
1. In addition to a thick layer of peptidoglycan, Gram positive walls are
composed of a variety of other carbohydrate polymers. For example, polymers of teichoic acids (acidic polysaccharides) such as ribitol.
Teichoic acids are unique to Gram-positive organisms.
2. The antibody response of the host seems mainly directed against these polymers, rather than against the peptidoglycan.
3. There is no phospholipid outer membrane in Gram positives
What are Gram negative bacteria?
1. The peptidoglycan (mucopeptide) layer is thinner than Gram positive walls.

2. In addition to peptidoglycan, these walls also contain lipopoproteins.

3. Outside of the peptidoglycan, and attached to it by lipoprotein, is the important outer membrane, containing lipoplysaccharide (LPS).
What is the periplasmic space?
1. Space between the inner & outer membrane.
2. Contains some degradative enzymes that digest large molecules that could not be transported through the inner membrane.
3. Some enzymes that degrade antibiotics are located here,
i.e. penicillinases.
4. Chemoreceptors required for chemotaxis
The periplasmic space is unique to Gram-negative organisms.
What does the outer membrane do?
Outer membrane reacts with antibodies.

2. Blocks entry of large molecules into the periplasmic space.

3. The outer membrane serves as a barrier to antimicrobial agents and detergents.

4. Matrix proteins known as "porins," allow passage only of smaller molecules (non-specific entry).

5. Porins form a channel that limits passage of hydrophilic molecules across the OM to molecules of < M.W. 600-700
What is LPS?
1. The lipopolysaccharide located on the outer layer of the OM is known as endotoxin since it is bound to the bacterial cell and is toxic (causes shock & fever in Gram- sepsis).
2. Composed of a polysaccharide (responsible for antigenic specificity)
and lipid A (which confers the toxicity).
3. Lipid A is composed of glucosamine linked to fatty acids and
Lipid A is unique to Gram-negative organisms.
What is some more on LPS?
1. The polysaccharide is a polymer of many different monosaccharides.
2. The outer layer is composed of repeating oligosaccharide units,
termed "O" specific region.
3. The sugars impart immunological specificity to the cell since they
predominate at the very surface of the cell.
4. A comparison of the LPS from different serotypes reveals minor differences in sugar composition which is the basis of
the immunological specificity.
5. These polysaccharides are called "O" antigens.
how does the gram stain work?
1. The exact basis for the differential reactions of bacteria in the gram reaction is not known.
a. There is a very good correlation between the Gram reaction and many other important properties.
b. The most likely mechanism of the gram stain is based on a permeability difference caused by the thickness in the walls of the two types of bacteria.
What happens if he cell walll is removed from garm +?
If the cell wall is removed from a gram positive cell, it reacts as a gram negative in the staining procedure
2. Cell walls of gram positives become largely impermeable to low molecular weight compounds when the organisms are in 70% alcohol.
3. In gram negatives the dye-I2 complex rapidly leaks out through the wall.
What other organism might stain gram positive?
What does it mean to be alive?
Ingestion and assimilation of nutrients leading to growth
Excretion of waste
Reproduce independently
Adapt to changes in the environment
React to stimuli
What is a capsid?
a protein coat that surrounds the genome, also called a Coat or Shell
What is a capsomer?
repeating structural protein subunits that makeup the capsid--arranged in precise pattern
What is a nucleocapsid?
Genome + Capsid=
membrane that surrounds the nucleocapsid-not all viruses have this structure
What are the four morphological classes?
Helical symmetry: Capsomers are arranged in a tube-like structure around the nucleic acid
Icosahedral symmetry: roughly spherical; has 20 faces; most efficient packing arrangement
Enveloped viruses:nucleocapsid surrounded by lipid bilayer acquired from host
viral proteins embedded and protruding
Complex viruses:composed of several parts with different symmetry, or have a complex organization
how do viruses replicate?
1. Attachment (adsorption)-occurs via virus-specific proteins on virion to receptor on host cell
2. Penetration-virion or nucleic acid enters cell
3. Synthesis-virus-specific proteins made, viral nucleic acid replicated, more viral proteins made
4. Assembly (packaging)-structural units form coat with viral nucleic acid and any viral proteins inside
5. Release-viral progeny exit cell via lysis or budding
hospital acquired infections
What are legionella?
• Legionella only recognized as a cause of pneumonia within the last 25 years
motile, gram-negative bacteria
• rather slow-growing with complex nutrional requirements.
Found in freshwater habitats but widespread in man-made hot water systems.
Enters your lungs via aerosolized droplets.
Symptoms include fever, coughing, pneumonia
When did legionella emerge?
• Bellevue-Stratford Hotel in Philadelphia
• 58th annual convention of the Pennsylvania chapter of the American Legion.
• 140 conventioneers got sick as did another 72 people in or near the hotel. 34 died
Inhaled mist from the air-conditioning
Where else might legionella live>?
vegetable misters, whirlpool baths, showerheads, dental water lines
What does legionella do with protozoa?
In nature, Legionella can be found growing in biofilms or growing inside protozoa. The protozoa ingest the bacteria as food but the protozoa get a nasty surprise as Legionella has them for lunch
What do Macrophages do?
Engulf bacteria
Phagosome fuses with lysosome
Release of lysozyme, proteases, defensins, production of peroxide, superoxide, nitric oxide
Degradation of bacteria
Debris from dead bacteria released by exocytosis.
What is the type IV secretion system?
Icm/Dot system is comprised of about 25 genes
Appears to be adaptation of a plasmid conjugation system to a device involved in intracellular growth and subversion of host cell processes
What is development?
Development can be defined as changes in the morphology or functioning of bacteria that occur in response to signals from the environment.
Allows bacteria to adapt to its constantly changing environment
This implies changes in gene expression/activity in the bacterium
What are the changes to which bacteria must adapt?
Dessication (drying)
Exposure to toxins
Cell density
Spatial location
Carbon availability
Energy availability
Other nutrients
Salt (osmotic) stress
What are the steps required to adapt?
Survey the environment (sense the change)
Communicate changes or “signal transduction”
Respond to the signal - alter gene expression, enzyme activity, or both
What is a biofilm?
Defined as a community of microbes attached to a surface (biotic or abiotic)
Biofilms can be contrasted with planktonic or free-living, individual bacteria
Can be comprised of one or many species
The predominant lifestyle of bacteria in every environment studied
Why are biofilms interesting?
Most bacteria live in biofilms
Form in medical, industrial, and natural environments
Contribute to disease
Microbes growing in biofilms are highly resistant to biocides e.g. antibiotics
Where are biofilms often found?
Implant infections
Artificial hips
Contact lenses
Dental equipment
Artificial heart
Cystic Fibrosis
What is the problem with biofilms?
Can be up to 1000X more resistant than planktonic bacteria
What are oppurtutiities for biofilms?
Implant infections
Artificial hips
Contact lenses
Dental equipment
Artificial heart
Cystic Fibrosis
What are attachment signals?
Environmental cues
Available carbon/energy
Sufficient oxygen
Sufficient iron
Low salt stress
What are some biofilms regulated by?
Inorganic Pi
What are defining step in a developmental pathway?
There are a defined series of changes bacteria proceed through as they develop
These changes can be blocked by disrupting the DNA which codes for proteins required for development
By observing where or when in the pathway development is stopped, discrete steps in this process can be determined
What are flagella?
-Swimming Motility
-30 mm/sec
-Movement through liquid
(attachment structure)
What are pili?
-Requires type IV pili
-Twitching motility - surface movement
-0.3 mm/sec
What attachment facor is needed for attachment?
What mutation prevents the formation of a biofilm? why?
mutation in the sadb gene, can attach but can't form monolayer
What is quorum sensing?
P. aeruginosa uses the quorum sensing system to go from small microcolonies to larger macrocolonies referred to as the mature biofilm.
Quorum sensing: the ability of bacteria to count their numbers or density
What are properties of a mature biofilm?
Resistance to antibiotics
Well separated macrocolonies
Channels allow the flow of liquids between the colonies -a primitive circulatory system??
Heterogeneity-bacteria throughout the biofilm experience different environments.
What is the detachment signal for P. aeruginosa?
What is West Nile Virus?
Arbovirus - arthropod-borne
Single stranded RNA virus, + strand
Enveloped virus
What are dead end hosts for west nile?
people and horsies
What population seems to correspond to westnile?
Declining American Crow Populations: 45% decrease
observed abundances (circles) versus estimates
(solid lines with 95% confidence limits)
What are our 6 major diseases with animal vectors?
Measles cattle
TB cattle
Smallpox cattle
Flu pigs and ducks
Pertussis pigs, dogs
Malaria birds
What are the five stages through which pathogens of animals evolve to cause disease confined to humans?
animals only, only from animals (WNV), from animals and then a few cycles in humans, from animls and then many (flu, cholera) and only in humans (smallpox, measles, syphilis)
What must happen for a stage 5 infection to persist?
For a stage 5 disease to persist, each infected individual must on average give rise to an infection in another individual.
What are the differences between diseases in temperate and tropical areas?
Higher proportion transmitted via insect vectors in the tropics
Animal reservoirs are more frequent in the tropics (8/10) than in the temperate zone (3/15)
Most of the temperate diseases are acute rather than chronic
Most of the temperate but none of the tropical diseases are so-called crowd epidemic diseases:
Ones occurring locally as a brief epidemic and capable of persisting only in large human populations
A higher proportion of the diseases confer long lasting immunity in the temperate zone versus the tropics.
What is the old world vs the new world for disease?>
Of the 25 diseases, only Chagas’ disease clearly originated in New World
• 13 of the 14 major species of domesticated livestock originated in the Old World (cow, sheep, goat, pig, horse)
• New World: only the llama and it is not known to have infected us with any pathogens.
• Genetic distance between humans and monkeys is greater in the New World than in the Old World and there was more evolutionary time for transfer to occur.
What is Chagas disease?
Trypanosoma cruzi
Endemic throughout much of Mexico, Central America and South America - 8 to 11 million infected.
Parasite is passed via an insect vector.
Charles Darwin may have had it.
What are the next big killers?
While the principles of pathogen transmission have not changed in the last 11,000 years, changing modern conditions are exposing us to new pathogen reservoirs and new modes of transmission.
Which will not become big killers?
Anthrax, BSE, Ebola, Marburg
Kill a high fraction of infected victims
inefficient transmission assures few infected victims
What does wolfe believe people have over freaked out about?
West Nile virus, hantavirus and Lyme Disease have aroused more fear than their lack of human-to-human tranmission and modest buden of morbidity and mortality seem to warrant
Of course, if any of these pathogens evolve new modes of more efficient transmission (e.g. by aerosolized respiratory droplets), they could become dangerous..
What diseases do the authors fear?
Yellow fever
What is up with bacteria and oxygen in the ocean?
smart to have backup, in ocean these bacteria use oxygen but if run low will use proteorotobsin to generate oxygen, pulls through in the clinch, can be used to make energy for human use one day
What did the notice about mouth and antibitoics?
everytime you take antibiotics natural selection is going on the mouth, tracked straptococci in the mouth, effect lasted longer than 6 months, could make them more susceptible to infection
What is the deal with the anthrax vaccine
Anthrax vaccine, not much fun because it requires six shots over 18 months, and boosters, developing a new one, whole bacteria that has been inactivated, produces two doses and less irritable
What is the problem with water a terrorists
Anthrax in the water, terrorists may contaminate water systems, could it be disinfected, can join biolfims in water pipes, not effective for spores, looking chemicals etc
What is a dual use dilemma?
refers to research that can help or harm, ambiquity makes it importatnt to regulate, needs to make sure scientists can't stifle scientists, hopes to strike a balance
What are mitochondria?
Mitochondria-where energy from sugars is released for cell use
What are chloroplats, golgi, ER, and ribosomes?
Chloroplasts-contain chlorophyll pigment
Gogli-sites of protein processing
ER-set of membranes in cytoplasm for translation
Ribosomes-bodies in cytoplasm where protein are constructed, contain RNA
how is Prokaryotic dna arranged?
Prokaryotes have DNA arranged in a single chromosome which is in a closed loop versus humans which have the DNA, eukaryotes go through mitosis
In prokaryotes reproduction occurs by chromosome duplication followed by cell fission
What were the five kingdoms?
Monera-Bacteria, all monera are prokaryotes
Protista-eukaryotes such as protozoa, slime molds, and single celled algae, usually have flagella
Fungi-includes fungi and yeat, non pigmented eukaryotic, have cells walls with unique chemical constituents
Fungi usually in long branching chains, cytoplasm mingles among adjacent cells
Last two are animala and Plantae
What kingdom are viruses in?
Viruses are not considered cellular entities, not placed in a kingdom
What are the three domains?
Archaebacteria are prokaryotic forms with unique biochemical propertie
Eukarya-the other four kingdoms
How do archaea and bacteria differ?
Archae and bacteria differ in the form of RNA in their ribosomes, the composition of their cell walls, and their sensitivity to certain antibiotics, archaea are awesome and kick ass
2/3 of genes in methanococcus are different-proteins involved in DNA replication are different in archaea
When did Eukaryotes evolve?
Eukaryotes-evolved 1.5 million years ago
What are cyanobacteria?
Cyanobacteria-photosynthetic bacteria (blue-green algae) used chlorophyll pigments in photosynthesis to capture light and energy and thus welcome oxygen.
From 1 to 21%
Why are bacteria critical?
Bacteria are critical-metabolize nutrients, break down the dead, trap nitrogen
Small percentage are infectious agents
Give human population chance to renew itself
what are tetrads?
four to eight
What are spirochetes and spirilla?
Spirochetes-spiral form that is rigid
Spirilla-spiral form that is flexible
Describe bacterial cytoplasm
What is the first key step for identifying bacteria?
gram staining
What happens when the cell wall is the drug target?
Some antibiotics prevent the bacterium from synthesizing peptidoglycan, internal pressures will cause swelling and bursting
What is glycocalyx?
Glycocalyx-coating which is also known as a capsule if tightly bound to cell or slime layer if slimy and flowing, provides protection
What is a pilis?
hairlike structure that helps bacteria attach to tissues or other surfaces
What are plasmids?
tiny loops of DNA that are suspended in the cytoplasm and have genes for proteins that are not used in essential functions
What is a spore? Who uses it?
Spore-has chromosome, two cell membranes, a cortex, a spore coat, and surroun ding wall called exosporium
Spore formation is key for bioterrorism
Anthrax-causes blood hemmoraging
What is Binary fission?
results in a colony of genetically identical cells, will increase in size and replicate DNA, new cell wall forms down the middle, and they separate
What is a culture median?
Culture median-water solution of various nutrients that encourage growth ie agar

In liquid form the culture is called borth
Agar is pretty common-will remain solid for a long time
What is an enriched media?
enrich so break stuff down and then can see thei activity
What do certain viruses do?
attack bacteria-these are called bacteriophages and have a head and tail
Give the viral overview?
Virus consists of a core of nucleic acid, a covering of protein, and some cases an envelop
There is no chemistry going on within a virus, there is no intake of nutrients and there are no waste products, do not increase or decrease in size, THEY DO REPLICATE AND THEY DO IT WELL
How do viruses replicate?
First they attach, then the genome is passed into the cell(penetration stage), the cell cytoplasm then removes the protein capside from the viral genome, then in the uncoating stage the vviral nucleic acid is released, then in the synthesis stage things differ depending on whether DNA or RNA. If DNA DNA will act like in us, if RNA it will just encode, proteins begin to appear in cell cytoplasm some of these function as enzymes and hook nucleotides together and synthesize new fragments of viral nucleic acid, other enzymes stitch togeth the amino acids for viral capsules, once viral parts have been synthesized they are combined to form new viral particles+assembly stage
Do not bring along ribsomes, cell breaks down and dies releasing the virus=release stage
After nucleocapsid forms it moves and steals some cell membrane, this punctures the cell membrane by the nucleocapsids=the lytic cycle
What are protists?
Protozoa, single celled algae, and the slime molds
Protests are unicellular, but some exist as colonies some capture food by phagocytosis while others simply ABSORB, MANY ARE PHTOSYNTHETIC, use cilia, flagella, or pseudopodia
Most reproduce by asexual reproduction by mitosis, but sexual reproduction also occurs , some species fuse entire cells, and other species come together to exchange nuclei, some may even do gamete formation
Develop nuclei, mitochondria, chloroplasts, and other organelles
Protozoa-first animal, lack cell walls, ingest food particles, move freely, produce no sporebearing structures
What are cysts?
protective bodies and withstand adverse environmental conditions
What are zooplankton?
animallike component of acquatic food chains
What are fungi?
emerged and were prevalent after Permian extinction
What are yeasts known for?
Yeasts known for their fermentation abilities
What are mushrooms?
Mushroom-filamentous mass of mold clings together tightly and forms a compact structure we call a mushroom
What are fungi?
Why would life suck without fungi?
Without fungi all the nutrients in organic material would be locked up
Have have fungi adapted their cell shape?
Size of Eukaryotic cells is limited by several factors-surface to volume ratio, fungi have adapted to avoid this issue by having flat cells which increases this ration
Many species of fungi have multiple nuclei in a single cell
Decribe fungi cells?
Cell walls-made of chitin
Fungal cells have nuclei, most species are sporebearing, have no chlorophyll, produce sexually and asexually, have threadlike strands,have cell walls form a unique polysaccharide called chitin
Many fungi have partitions between cells called spta, these are not complete
What arte saprobes?
Saprobes-live on dead organic matter, some are parasites and feast on the living,
Many live in acidic conditions, so common in acidic foods
How do toxins act on the body?
Secretion of toxin with local affect (cholera, food poisoning)
Infammatory response to the infection which leads to scarring of tissue ie stds and tuberculosis
Bacterial toxins causing a systematic effect especially with blood (ie anthrax, meningococcus
What are the roots of infection?
Airborne(tuberculosis, anthrax, meningococcus)
Tick borne (lyme disease)
Flea born (plague)
Direct contact: Gonorhea, meningococcus
Food born-cholera, typhoid, e coli
Local Spread: UTI
What happens with meningococcus?
Meningococcus:high fever, rash, headache, stifnness of neck
Caused by Neisseria Meningitidis, breaks through mucus membrane in throat, survives in blood and secretes toxin
who is more at risk for legionella?
Older, smoker, drinkers etc sets you at risk
What is similar to an amoeba that might have allowed legionella to become a human pathogen?
What is a required killing factor to kill macrophages?
What is Icm Dot?
the genes thaqt cause type 4 secretions
what is the goal of the macrophage?
degrade that bacteria, depris released
What happens when Legionella is ingested?
Legionella presents fusion with lysosomes, does not acidify
Make apartment for themselves
Use type 4 secretions system to send thigns into the cytosome
Can deliver DNA plus protein, some can just deliver proteins
Legionella pass proteins
Legionella is inside phagosome and want to send things across the mebrane into the cytosol
What does pertussis also use?
Pertussis-whooping cough, sends in secretion via type 4
What is another way to have osmotic stress?
Sugar is another way to have osmotic stress
What happens when bacteria attach?
change gene expression
What is one giant biofilm we see way too much?
how resistant is a biofilom?
Biofilm are 1000 more resistant than free living
What is pseudomonas?
gram negative, motile, opportunistic pathogen, in cystic fibrosis a lot, problem with burn patients
What is bad gift for a hospitalized friend?
A potted plant
How do biofilms form?
Form monolayer which forms microcolony which means you get a mature biolfim
Happens within 24 hours
how prevalent is legionella?
Legionella-1500 cases ayear, most healthy people have no problems
Ventilators have problem
What is legionella in the midst of doing?
What sends an important signal?
Iron is an important signal
What is the assay thing?
Assay, can grow in the 96 wells, do the bacteria like to adhere
Dump bacteria out and stain with crytstal violet
Quantify by dissolving crystal violet in ethanol
What is the deal with SadB
SadB-never produce to irreversibly attached stage
So SadB is involved after the reversible attachment
How do bacteria count themselves?
Bacteria can count themselves-by quorum sensing, want to know because
Each bacteria releases small molecules so bacteria have a way of assessing-biofilm is a group behavior
What is the Fatality of WNV?
Fatality can be up to 50%, but with people its less than 1%
when did WNV come here?
Misquito over in airplane, heads for the zoo and kills birdies, crows are very susceptible
What is West Nile Virus doing in the population?
West Nile virus is cycling in the bird population, so there is a reservoir for west nile
What happened with horses?
Horses went extinct 18,000 years ago and the Spanish brought them back
Why aren't llamas a problem?
WE don’t have a lot of llamas living in close proximity
What is chagas disease?
Chagas Disease-similar to African sleeping sickness
Can’t infected ftrom parasites in their feces which makes this disease alittle harder to deal with so anywhere there are feces there can be a problem