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183 Cards in this Set
- Front
- Back
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What are the factors responsible for emergence of a disease
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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 |
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What fraction of the population died during the plague?
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1/3
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What was the etiological agent of Medieval Black Death?
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Yersinia pestis
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What was the problem with quarantine during the plague?
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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.
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What did Van Leewenhoek do?
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he did the microscope
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What was the theory of Spontaneous Generation?
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• 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 |
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What did REdi do?
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Didn't buy sponataneous generation so did the meat in the beaker thing
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How did Louis's goes neck work?
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Dust and microorganisms were trapped in the bend and so the liquid remains sterile for years
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What did Koch do?
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Credited with demonstrating the first direct link between a single microbe and a single disease – Tuberculosis
Set up Koch's postulate |
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What did Hesse do?
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Introduces the use of agar
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What was the Golden Age of Microbiology?
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Applied principles and methods elucidated by Koch and Pasteur
Identified the causative agent of many important diseases including TB, plague, cholera, tetanus, influenza 1854-1920 |
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What did Semmelweis propose?
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wash your hands you fucking morons
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What did Jenner do?
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the first vaccine against small pox!!
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What are non communicable diseases?
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Genetic Diseases (e.g., PKU, Tay-Sachs, schizophrenia, some cancers)
Nutritional Deficiencies (e.g., scurvy, beriberi) |
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What are communicable diseases?
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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) |
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What are genetic diseases?
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Genetic Diseases
(e.g., PKU, Tay-Sachs, schizophrenia, some cancers) Epidemiological Framework: Mendelian & Population Genetics Treatment Options: Genetic and Phenotypic Therapies |
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What are nutritional deficiencies?
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Nutritional Deficiencies
(e.g., scurvy, beriberi, dehydration) Epidemiological Framework: Individual and Population Nutrition Treatment Options: Diet Alterations |
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What are spongiform diseases?
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Transmissible Spongiform Encephalopathies
or Prion Diseases (e.g., scrapie, Creutzfeld-Jacob Disease, chronic wasting disease) Epidemiological Framework: Transmission Treatment Options: Transmission Prevention |
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What are infectious diseases?
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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 |
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what type of interactins are infectious diseases?
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predator-prey
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Who is the father or modern medicine?
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Hippocrates
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). |
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What did James Lind do?
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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. |
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How did Lind do his experiments>
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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. |
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What is scurvy caused by?
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Scurvy is caused by Vitamin C deficiency
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What did Koch do with Anthrax?
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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. |
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How does Koch's postulate work?
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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. |
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What did Pasteur do with anthrax?
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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. |
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What are the thre main approaches to the modern practice of epidemiolog?
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Experimental Studies
Statistical Studies of Populations Modeling Studies of Theoretical Species |
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What is prevalance?
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Prevalence is the percent of a specific population with the disease.
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Can epidemiology be predictive?
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Yes! It's the stupid model!
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What is equilibrium?
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We can ask whether this population will settle to some point where the abundances of the three types of individuals will stop changing.
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How do we find the equilibrium?
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Set each equation equal to 0 and simplify
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What can the presence fo disease do to a population?
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However, the presence of disease can “regulate” the population (i.e., keep it from zooming off to infinity).
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What do epidemiologist investigate in the infectious disease cycle?
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Characteristics of the infectious organism
Source and or reservior of the infectious organism Mode of transmission Susceptibility of the host Exit mechanisms |
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how many pathogen species are there that can infect humans?
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538 bacteria
317 fungi 287 helminths 208 viruses 57 protozoa |
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What are prokaryotes?
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Non-eukaryote
Lacking a nucleus, mitochondria, spliceosomal introns and spliceosomes Possessing transcriptionally coupled translation |
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What differebces are often important for understanding the mechanisms of action of chemotherapeutic agents
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1. Chromosome(s)
2. Organelles (mitochondria & other membrane bound structures) 3. Mechanism of cellular movement 4. Cell wall |
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Compare Eucaryotic and procaryotic chromosomes?
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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. |
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Compare Eucaryotic and procaryotic organelles?
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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. |
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compare motility in eucaryotic and procaryotic cells?
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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). |
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Compare the cell walls and eucaryotic and procaryotics cells?
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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. |
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How is the cell wall important for antibiotics?
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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
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What is the evidence for the difference between Archaea an Bacteria?
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rRNA
Cell walls Cell membranes 2/3 of genes in various seqeunced archaebacterial genomes differ from eubacteria |
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What are extremophiles?
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So named because thought to be similar to bacteria that must have lived on primitive earth
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What are stromatolites?
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“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.”
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What is the deal with sirface area to cell volume ratio?
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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 |
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What is coccus?
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Sperical form or "coccus”
From Greek meaning “berry” |
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What is bacillus
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Rod shaped or "bacillus”
From Greek meaning “little walking stick |
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What is spiral?
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Curved rod or spiral shape
From Greek meaning “little coil |
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How are bacterial cells arrnaged
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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. |
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How does the plasma membrane differ in archaea?
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They have Lipid monolayer
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Compare tghe linkage, structure, and sterols on the bacterial, archaeal, and eukaryotic membranes
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Bacteria and Euk have ester bonds whereas Archaea have ether bonds
Archaea have a lipid monolayer, and only Euk have sterols |
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What are sterols?
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rigid planar molecules, stabilize membrane,
can be 5-25% of total lipids. Example - cholesterol |
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What are the function of the cytoplasmic mebrane?
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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. |
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What does the cell wall do?
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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. |
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What else does the cell wall do?
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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 |
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What is peptidoglycan?
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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. |
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What bacteria do not have cells walls?
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mycoplamsa!
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What does not have peptidoglycan?
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archaea!!
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What do gram + bacertia have?
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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 |
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What are Gram negative bacteria?
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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). |
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What is the periplasmic space?
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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. |
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What does the outer membrane do?
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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 |
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What is LPS?
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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 pyrophosphate. Lipid A is unique to Gram-negative organisms. |
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What is some more on LPS?
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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. |
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how does the gram stain work?
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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. |
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What happens if he cell walll is removed from garm +?
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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. |
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What other organism might stain gram positive?
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yeast
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What does it mean to be alive?
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Ingestion and assimilation of nutrients leading to growth
Excretion of waste Reproduce independently Adapt to changes in the environment React to stimuli |
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What is a capsid?
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a protein coat that surrounds the genome, also called a Coat or Shell
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What is a capsomer?
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repeating structural protein subunits that makeup the capsid--arranged in precise pattern
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What is a nucleocapsid?
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Genome + Capsid=
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Envelope?
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membrane that surrounds the nucleocapsid-not all viruses have this structure
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What are the four morphological classes?
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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 |
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how do viruses replicate?
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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 |
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What aRE NOSOCOMIAL INFECTIONS?
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hospital acquired infections
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What are legionella?
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• 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 |
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When did legionella emerge?
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• 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 1976 |
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Where else might legionella live>?
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vegetable misters, whirlpool baths, showerheads, dental water lines
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What does legionella do with protozoa?
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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
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What do Macrophages do?
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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. |
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What is the type IV secretion system?
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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 |
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What is development?
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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 |
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What are the changes to which bacteria must adapt?
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Dessication (drying)
Heat Competitors Exposure to toxins Cell density Spatial location Carbon availability Energy availability Other nutrients Oxygen pH Salt (osmotic) stress |
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What are the steps required to adapt?
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Survey the environment (sense the change)
Communicate changes or “signal transduction” Respond to the signal - alter gene expression, enzyme activity, or both |
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What is a biofilm?
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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 |
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Why are biofilms interesting?
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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 |
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Where are biofilms often found?
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Implant infections
Catheters Artificial hips Contact lenses Respirators Dental equipment Artificial heart Diseases Cystic Fibrosis |
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What is the problem with biofilms?
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Can be up to 1000X more resistant than planktonic bacteria
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What are oppurtutiities for biofilms?
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Implant infections
Catheters Artificial hips Contact lenses Respirators Dental equipment Artificial heart Diseases Cystic Fibrosis |
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What are attachment signals?
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Environmental cues
Available carbon/energy Sufficient oxygen Sufficient iron Low salt stress |
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What are some biofilms regulated by?
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Inorganic Pi
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What are defining step in a developmental pathway?
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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 |
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What are flagella?
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-Swimming Motility
-30 mm/sec -Movement through liquid (attachment structure) |
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What are pili?
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-Requires type IV pili
-Twitching motility - surface movement -0.3 mm/sec |
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What attachment facor is needed for attachment?
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flagella
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What mutation prevents the formation of a biofilm? why?
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mutation in the sadb gene, can attach but can't form monolayer
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What is quorum sensing?
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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 |
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What are properties of a mature biofilm?
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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. |
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What is the detachment signal for P. aeruginosa?
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starvation
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What is West Nile Virus?
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Arbovirus - arthropod-borne
Single stranded RNA virus, + strand Enveloped virus |
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What are dead end hosts for west nile?
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people and horsies
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What population seems to correspond to westnile?
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Declining American Crow Populations: 45% decrease
observed abundances (circles) versus estimates (solid lines with 95% confidence limits) |
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What are our 6 major diseases with animal vectors?
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Measles cattle
TB cattle Smallpox cattle Flu pigs and ducks Pertussis pigs, dogs Malaria birds |
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What are the five stages through which pathogens of animals evolve to cause disease confined to humans?
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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)
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What must happen for a stage 5 infection to persist?
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For a stage 5 disease to persist, each infected individual must on average give rise to an infection in another individual.
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What are the differences between diseases in temperate and tropical areas?
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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. |
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What is the old world vs the new world for disease?>
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Of the 25 diseases, only Chagas’ disease clearly originated in New World
Temperate: • 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. Tropical: • 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. |
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What is Chagas disease?
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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. |
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What are the next big killers?
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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.
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Which will not become big killers?
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Anthrax, BSE, Ebola, Marburg
Kill a high fraction of infected victims inefficient transmission assures few infected victims |
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What does wolfe believe people have over freaked out about?
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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.. |
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What diseases do the authors fear?
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Influenza
Cholera Tuberculosis HIV Yellow fever |
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What is up with bacteria and oxygen in the ocean?
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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
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What did the notice about mouth and antibitoics?
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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
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What is the deal with the anthrax vaccine
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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
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What is the problem with water a terrorists
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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
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What is a dual use dilemma?
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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
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What are mitochondria?
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Mitochondria-where energy from sugars is released for cell use
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What are chloroplats, golgi, ER, and ribosomes?
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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 |
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how is Prokaryotic dna arranged?
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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 |
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What were the five kingdoms?
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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 |
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What kingdom are viruses in?
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Viruses are not considered cellular entities, not placed in a kingdom
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What are the three domains?
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Archaebacteria are prokaryotic forms with unique biochemical propertie
Traditonal-Eubacteria Eukarya-the other four kingdoms |
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How do archaea and bacteria differ?
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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 |
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When did Eukaryotes evolve?
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Eukaryotes-evolved 1.5 million years ago
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What are cyanobacteria?
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Cyanobacteria-photosynthetic bacteria (blue-green algae) used chlorophyll pigments in photosynthesis to capture light and energy and thus welcome oxygen.
From 1 to 21% |
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Why are bacteria critical?
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Bacteria are critical-metabolize nutrients, break down the dead, trap nitrogen
Small percentage are infectious agents Give human population chance to renew itself |
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what are tetrads?
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four to eight
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What are spirochetes and spirilla?
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Spirochetes-spiral form that is rigid
Spirilla-spiral form that is flexible |
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Describe bacterial cytoplasm
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transparent
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What is the first key step for identifying bacteria?
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gram staining
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What happens when the cell wall is the drug target?
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Some antibiotics prevent the bacterium from synthesizing peptidoglycan, internal pressures will cause swelling and bursting
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What is glycocalyx?
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Glycocalyx-coating which is also known as a capsule if tightly bound to cell or slime layer if slimy and flowing, provides protection
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What is a pilis?
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hairlike structure that helps bacteria attach to tissues or other surfaces
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What are plasmids?
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tiny loops of DNA that are suspended in the cytoplasm and have genes for proteins that are not used in essential functions
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What is a spore? Who uses it?
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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 |
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What is Binary fission?
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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
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What is a culture median?
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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 |
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What is an enriched media?
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enrich so break stuff down and then can see thei activity
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What do certain viruses do?
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attack bacteria-these are called bacteriophages and have a head and tail
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Give the viral overview?
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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 |
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How do viruses replicate?
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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 |
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What are protists?
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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 |
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What are cysts?
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protective bodies and withstand adverse environmental conditions
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What are zooplankton?
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animallike component of acquatic food chains
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What are fungi?
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emerged and were prevalent after Permian extinction
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What are yeasts known for?
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Yeasts known for their fermentation abilities
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What are mushrooms?
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Mushroom-filamentous mass of mold clings together tightly and forms a compact structure we call a mushroom
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What are fungi?
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Fungi=decomposers
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Why would life suck without fungi?
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Without fungi all the nutrients in organic material would be locked up
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Have have fungi adapted their cell shape?
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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 |
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Decribe fungi cells?
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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 |
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What arte saprobes?
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Saprobes-live on dead organic matter, some are parasites and feast on the living,
Many live in acidic conditions, so common in acidic foods |
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How do toxins act on the body?
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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 |
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What are the roots of infection?
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Airborne(tuberculosis, anthrax, meningococcus)
Tick borne (lyme disease) Flea born (plague) Direct contact: Gonorhea, meningococcus Food born-cholera, typhoid, e coli Local Spread: UTI |
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What happens with meningococcus?
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Meningococcus:high fever, rash, headache, stifnness of neck
Caused by Neisseria Meningitidis, breaks through mucus membrane in throat, survives in blood and secretes toxin |
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who is more at risk for legionella?
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Older, smoker, drinkers etc sets you at risk
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What is similar to an amoeba that might have allowed legionella to become a human pathogen?
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macrophages
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What is a required killing factor to kill macrophages?
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Mil
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What is Icm Dot?
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the genes thaqt cause type 4 secretions
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what is the goal of the macrophage?
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degrade that bacteria, depris released
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What happens when Legionella is ingested?
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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 |
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What does pertussis also use?
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Pertussis-whooping cough, sends in secretion via type 4
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What is another way to have osmotic stress?
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Sugar is another way to have osmotic stress
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What happens when bacteria attach?
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change gene expression
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What is one giant biofilm we see way too much?
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plaque
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how resistant is a biofilom?
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Biofilm are 1000 more resistant than free living
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What is pseudomonas?
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gram negative, motile, opportunistic pathogen, in cystic fibrosis a lot, problem with burn patients
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What is bad gift for a hospitalized friend?
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A potted plant
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How do biofilms form?
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Form monolayer which forms microcolony which means you get a mature biolfim
Happens within 24 hours |
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how prevalent is legionella?
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Legionella-1500 cases ayear, most healthy people have no problems
Ventilators have problem |
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What is legionella in the midst of doing?
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evolving
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What sends an important signal?
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Iron is an important signal
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What is the assay thing?
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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 |
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What is the deal with SadB
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SadB-never produce to irreversibly attached stage
So SadB is involved after the reversible attachment |
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How do bacteria count themselves?
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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 |
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What is the Fatality of WNV?
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Fatality can be up to 50%, but with people its less than 1%
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when did WNV come here?
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Misquito over in airplane, heads for the zoo and kills birdies, crows are very susceptible
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What is West Nile Virus doing in the population?
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West Nile virus is cycling in the bird population, so there is a reservoir for west nile
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What happened with horses?
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Horses went extinct 18,000 years ago and the Spanish brought them back
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Why aren't llamas a problem?
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WE don’t have a lot of llamas living in close proximity
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What is chagas disease?
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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 |
