MCB 2000 Exam FOUR Study guide Feel free to add to questions or make corrections :) 1. What are chemotherapeutic agents? ● Any chemicals used for treatment, relief, or prophylaxis (used to prevent an infection) of a disease 2. List the characteristics of an ideal antimicrobial drug? ● Toxic: SelectWe also discuss several other topics like What is technical picture continuity?
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ively toxic to the microbe but nontoxic to host cells ● Microbicidal: Microbicidals (kills) rather than microbistatic (stops growing, doesn’t kill) ● Soluble: Relatively soluble; function even when highly diluted in body fluids ● Remains: Remains potent long enough to act and is not broken down or excreted prematurely ● Resistant: Does not lead to the development of antimicrobial resistance ● Complements: Complements or assists the activities of the host's defenses ● Fluids: Remains active in tissues and body fluids ● Readily: Readily delivered to the site of infection ● Price: Reasonable priced ● Health: Does not disrupt the host’s health by causing allergies or predisposing the host to other infections 3. What are the differences between natural, and semisynthetic antibiotics? ● Natural drugs: antibiotics naturally made by microbes to kill competition (fungi and some bacteria; penicillin) ● Synthetic drugs: completely manmade ● Semisynthetic drugs: originally produced by microbes but scientist modify in lab 4. List sites on infectious agents that could be used as a target for antimicrobial agents ● Cell wall, Cell membrane, Metabolism, Protein synthesis, DNA/RNA synthesis 5. What is BetaLactam ring? Which group of antibiotics contain beta lactam ring? ● Betalactam ring: ring that is responsible for the action of penicillin; scientists manipulate penicillin to make them last longer and be more effective ● Most forms of penicillin have the ring (methicillin, amoxicillin, etc) ● Vancomycin does not have ring 6. Why ribosomes are excellent targets against many infectious diseases? ● Bacterial ribosomes are smaller and have different composition than human ribosomes which allows us to target them without hurting ourselves 7. Which groups of microorganisms produce antibiotics and why? ● Fungi and some bacteria produce antibiotics naturally to kill their competition (penicillin comes from fungi) 8. Describe the mechanism of action and name different antibiotics discussed in the course. ● Penicillin (first antibiotic discovered by Fleming) and cephalosporin target cell wall synthesis ● Methicillin: disrupts cell wall synthesis ● Streptomycin and tetracycline target protein synthesis ● vancomycin targets cell wall at different places than penicillin ● ciprofloxacin affects the enzyme that holds the DNA together (gyrase) ● rifampin/rifamcyin affect RNA synthesis9. Which of the above antibiotics inhibit: cell wall, cell membrane, protein/DNA/RNA synthesis ● Cell wall: penicillin, methicillin, other cillins, cephalosporin, bacitractin and vancomycin ● Cell membrane:polymyxin ● Protein Synthesis: Tetracycline and glycylcyclines ● DNA: ciprofolaxin ● RNA: rifamycin ● Folic Acid: Sulfasoxazole and trimethoprim 10. How UV light radiation damages bacteria? ● UV damages bacteria by forming thymine dimers in the DNA so it inhibits replication (causes mutations) ● It’s deep penetrating and causes cancer 11. Define selective toxicity. How this is a problem with developing antiviral and antifungal drugs ● Selective toxicity: where are the most vulnerable spots in bacteria, fungus, and viruses that humans can manipulate without hurting themselves ● Problems: Fungi: do not have many treatments because they are eukaryotic and very similar to humans which can cause many side effects Viruses: do not have many treatments because they are obligate intracellular pathogens, have no membrane, no cell wall, no protein synthesis, no replication or transcription; rely completely on host 12. List the Mechanisms by which bacteria develop resistance and spread to other bacteria ● Inactivate drug: some bacteria can break down betalactam ring (betalactase; penicillin resistance) ● Prevent entry: drugs must enter cell to be effective and some bacteria modify surface molecules/mutate and change target so drugs cannot enter ● Pump drug out: as the drugs come in, bacteria push it out ● Modify targets inside: drugs cannot be effective inside because target is different ● Use alternative pathways: use different pathways that are not disrupted by anti metabolize 13. Give examples and mechanisms of action of antifungal and antiviral drugs ● Antifungal drugs: two classes that both work against ergosterol structure and metabolism Polyenes: Amphotericin B; disrupt function of ergosterol Azoles: Fluconazole, Miconazole, Ketoconazole; disrupt synthesis of ergosterol ● Antiviral drugs: Inhibition of entry: Fuzeon/Enfuvirtide (prevent entry of HIV virus) Inhibition of nucleic acid synthesis: Acyclovir/Zovirax (structural analogs; mimic structures that prevent the virus from synthesizing their own DNA; most effective against herpesvirus), Zidovudine/AZT (affects synthesis of HIV virus; structural analog; RT inhibitor) Inhibition of assembly/exit: protease inhibitor drugs (protease enzyme chops proteins into small segments; good against HIV infection) 14. What is MIC, what are benefits of knowing this number?● MIC: minimum inhibitory concentration; lowest amount of drugs that kill/stop microbes from growing; needed so you know how much the smallest effective dose is for someone to take and to compare the dose to other antimicrobials 15. Define sterilization, name methods that achieve sterilization ● Sterilization: process that destroys or removes ALL life forms; including endospores ● Methods: autoclaving (chamber that fills with steam that pressurizes; temp reaches 121 degrees Celsiuskills everything), incineration (need higher temp and longer time than steam because steam penetrates), oven (need higher temp and longer time than steam because steam penetrates) filtration, xray, gamma ray, some gases and liquids 16. List the microbes according to their resistance to physical and chemical agents. Know the specifics of each group of organism that make them more resistance to chemical agents. ● (from least resistant to most resistant) enveloped viruses, G+ bacteria, nonenveloped viruses, fungi/fungal spores, G bacteria (OM and porins), protozoan trophozoites (active form; exist after ingestion), protozoan cysts (transmission form; what is ingested), staphylococcus (resistant strains; MRSA) and pseudomonas (causes opportunistic infections; has selective porins), mycobacterium, bacterial endospores (dormant; Bacillus and Clostridium), prions (infectious proteins) 17. List the physical and chemical methods of control of microbial growth? ● Physical: Heat: dry (incineration, oven), moist (steam, boiling water) Radiation: ionizing (xray, gamma ray; penetrate; break chromosomes and damage is irreversible; can cause cancer), nonionizing (UV; superficial damage/no penetration, causes thymine dimers in DNA which causes T’s to bond together resulting in mutations) ● Chemical: Antiseptics Disinfectants Chlorine is usually best option 18. Define prophylaxis ● action taken to prevent disease, especially by specified means or against a specified disease. 19. List and describe mode of action antiviral drugs discussed in the lectures. How antiHIV drugs work? How drugs against flu work? ● HIV drugs involve reverse transcriptase inhibitors and protease inhibitors that prevent the assembly and release of the virus ● Fuzeon prevents the entry of HIV virus into host cells ● Tamiflu and Relenza prevents the entry of the flu virus into a cell by interfering with the fusion of the virus with the cell membrane and the release of the virus 20. Difference between active and passive immunization. Know different forms of vaccine. ● Active immunization: make your own B cells and T cells and antibodies; vaccination ● Passive immunization: receive preformed antibody from someone else that is already made (can be person or animal); immunoglobulin therapy ● Forms of vaccines: Wholecell: killed vaccines (molecules from the bacteria/virus stimulate B cells and T cells; less effective) liveattenuated vaccines (weak bacteria/virus that can proliferate and divide which provides good protection; more effective; requires fewer doses; herd immunity; involves CMI) Subunit: take bacteria/virus DNA and use components to synthesize pieces of bacteria/virus in the laboratory; example: toxoid vaccinations (DPT vaccine) 21. What are some practical uses of ELISA test? Difference between direct and indirect ELISA? ● ELISA (enzyme linked immunosorbent assay): used to detect presence of infectious agent and measure amounttiter (qualitative and quantitative); based on the same antigen antibody interaction; make a plate with 96 wells and they put different amounts of antigen and antibodies in wells which interact; the enzyme attached to the antibody will develop color when a substrate is added; the more color the more enzyme the more antibody present ● Direct ELISA: detect presence of pathogen (antigen) ● Indirect ELISA: detect presence of antibodies produced by patient against an infection 22. Distinguish between natural acquired immunity and artificial acquired immunity. Give examples ● Natural acquired immunity: Active: getting sick Passive: receive antibodies from mother to fetus (via placenta) or from breastfeeding ● Artificial acquired immunity: Active: receiving a vaccine Passive: receiving preformed antibody from someone else through injection (immunoglobulin therapy) 23. Define cellmediated immunity? Humoral immunity? List their major components/cells involved ● Cellmediated immunity: immune response by T cells that does not involve antibodies but rather involves the activation of phagocytes and release of cytokines; T helper cells, Cytotoxic T cells and T regulatory cells are involved ● Humoral immunity: immune response by B cells that involves activating B cells which turn into plasma cells and secrete antibodies 24. Know different components of an antibody structure. Which part of antibody binds to antigen? ● Made of four pieces (2 identical heavy chains and 2 identical light chains); part of the antibody (top of the Y) that binds to the antigen is called Fab (antigen binding fragment); part of the antibody (bottom of the Y) that can bind to a cell is called Fc (constant fragment); there are five classes of antibodies that are different in their Fc portion; every antibody is different in their Fab portion 25. Define Opsonization. What is the effect of opsonization? Name two opsonin molecules ● Opsonization: when antibodies coat antigens with complement proteins; this aids phagocytosis so that it can remove infection ● Opsonins: IgG and IgA 26. What is meant by hypersensitivity? List, give examples, and briefly describe each type.● Hypersensitivity: body develops exaggerated response when it really should not; four types ● Type I: immediate (IgE); when you are allergic to something and you immediately respond with histamines (inflammatory compound); can be systemic or localized; ex: anaphylaxis allergies such as hay fever and asthma ● Type II: antibodymediated (IgG mediated); blood type incompatibilities (receive the wrong blood type and your body produces antibodies against the “foreign” RBCs) ● Type III: Immune complexmediated; immune complex deposited throughout the body; entrapment of immune complex results in inflammation which damages that area; when your immune system attacks your own tissues/cells (lupus, rheumatoid arthritis, rheumatic fever consequence of strep infection where the infection moves from the throat to other parts of the body like the heart, serum sicknesswhen you receive antibodies from someone that was developed in horses) ● Type IV: delayed and CMI involved; takes time for it to go through T cells and CMI (poison ivy, graft rejection, TB skin test, contact dermatitis) 27. Name several immunodeficiency diseases, indicate the target tissue in each case ● Immunodeficiency: someone is missing components of their immune system; can be genetic or acquire them later in life ● Primary immunodeficiency diseases: born with it; Agammaglobulinemic (no B cells), DiGeorge syndrome (no T cells), no phagocytic cells, no complement proteins ● Secondary immunodeficiency diseases: develop later in life; caused by AIDs, nutrition deficiencies, stress, pregnancy, aging, irradiation, severe burns, steroids, immunosuppressive drugs, removal of spleen ● Autoimmune diseases: lupus (systemic), rheumatoid arthritis (systemic), Grave’s disease (thyroid), Myasthenia gravis (muscle), type 1 diabetes (pancreas), multiple sclerosis (myelin) 28. What is meant by secondary (acquired) immunodeficiency disease? Define primary immunodeficiency. Give example of each. ● Acquired immunodeficiency disease: when you develop an immunodeficiency disease later in life from natural causes (AIDs, nutrition deficiencies, stress, pregnancy, aging) or from immunosuppressive agents (irradiation, severe burns, steroids, immunosuppressive drugs, removal of spleen) ● Primary immunodeficiency: A disorder caused by an inherited flaw in the immune system that increases the susceptibility to infections. ○ Example: Agammaglobulinemia (Xlinked, nonsexlinked) low levels of B cells and antibodies DiGeorge Syndrome (lack of all classes of T cells) 29. What are the differences between disinfectants and anticeptics? ● Disinfectants: physical or harsh chemical agents that destroy germs, vegetative pathogens, and toxins; used to clean inanimate objects; do not kill endospores ● Antiseptics: used to reduce the number of microbes on human tissue and skin; milder than disinfectants 30. List and describe the antibacterial actions of skin, mucous membrane?● Skin: sweat, high salt, low pH, lysozyme (enzyme that kills cell wall of bacteria), normal flora (prevents other bacteria from establishing) ● Mucous membrane: covered with mucus (layer of insulation that covers mucous membrane which covers respiratory and urinary tract) 31. Name the elements involved in nonspecific immunity, Give examples for each. ● Physical and chemical barriers, inflammation, fever, phagocytes, and proteins ● Skin and mucous membrane 32. What are the complements? What are their functions? ● Complement system: complements immune reactions and consists of over 30 different blood proteins that work to destroy bacteria and viruses; three different complement pathways and the final stage of each pathway is the same MAC which lyse cells ● Complement proteins: part of second line of defense; group of proteins floating in the blood on a regular basis; inactive form until sensing an infection (active); complement fixation is process of complement proteins being activated ● Complement fixation: when complement proteins start breaking down into pieces and accumulate on surface of bacteria which eventually this results in formation of membrane attack complex (MAC) that pokes a hole in bacteria and lyses bacteria cells; then they coat bacteria with complement proteins (called opsonization) which attracts phagocytic cells and makes their job easier to remove the dead bacteria 33. List and describe different forms of vaccine. (Read ALL of section 13.6)34. Compare killed vaccine vs. live attenuated vaccine? What is meant by subunit vaccine? ● attenuated vaccine is a weakened form of the virus that can divide and provide protection and life long immunity, but killed vaccines cannot divide and require a higher dosage ● a subunit vaccine is parts of DNA, protein pieces, or inactivated toxins (toxoids) of a virus or bacteria that are synthesized in a lab to create a vaccine against an infection 35. What are MHC proteins? What is their significance? ● MHC protein: every cell in the body except RBCs have MHCI; everyone’s MHCI is different except identical twins ● Significance: when you get a graft/transplant from someone the MHC is different and you react to it and macrophages destroy those cells 36. Define: lymphocytes, leukocytes, and erythrocytes ● Lymphocytes: T cells, B cells, Natural Killer cells; subtype of leukocyte; primary cells involved in specific immune reactions to foreign matter ● Leukocytes: WBCs● Erythrocytes: RBCs 37. What are the differences between different forms of B cells ● plasma cells are the only kind of B cells that produce antibodies, activated B cells ● memory B cells are partially activated B cells that do not produce antibodies and become activated when an infection enters the body, have a longer life compared to activated B cells 38. What are cytokines? Interferon? Give examples ● Cytokines: proteins produced by immune cells; used for attacking bacteria, communication, activation of each other Example: if T cells want to tell B cells to multiply and make more B cells, they produce cytokines to trigger B cell to multiply ● Interferons: cytokines produced by some cells; important against fighting viruses; natural antivirals Example: one cell is infected by virus, that cell produces interferon which goes and alerts other cells of infection so when the virus tries to attack other cells they know; usually kill RNA of virus 39. Define passive, active, artificial, and natural immunity produced against infectious agents. Give examples of each as discussed in class. ● passive occurs when you receive antibodies from someone else, when it is passed on from one person to another, like mother to fetus or breastfeeding ● artificial immunity is when you receive a vaccine that then makes you produce your own B and T cells ● natural immunity is when your body naturally produces B and T cells against an infection like when you get a cold 40. Name the primary and secondary lymphoid organs. Where all blood components are originated from? ● Primary lymphoid organs: thymus (where T cells mature) and bone marrow (where B cells mature; where B cells and T cells originate from stem cells) ● Secondary lymphoid organs: spleen, lymph nodes, tonsils, appendix, Peyer’s patches (B cells and T cells migrate in and out of lymphoid organs constantly) 41. What are the characteristics of primary and secondary immune response to infection ● Primary: first ever exposure to an infection; main antibody is IgM but slow to develop, low level (titer; concentration of antibodies) response, and does not last very long; memory cells produced as a result for next time Vaccines are developed to give you a primary response so that next time you have a secondary response when the actual infection tries to harm you ● Secondary: after the first exposure; mainly IgG; develops fast, higher response (titer), and lasts longer; response is much better than primary and prevents you from getting sick 42. What are the elements of first, second, and third line of defense ● First line of defense: innate/nonspecific; physical (skin, mucous membrane, cilia) and chemical (enzymes and molecules); no memory● Second line of defense: innate/nonspecific; phagocytosis (engulf infection), inflammation (reaction you get from swelling and redness; good for you; results in tissue repair), fever (temp rises to slow the infection), proteins (complement proteins); no memory ● Third line of defense: acquired/specific; B cells and T cells; has memory cells to remember infections for the next time 43. List (and explain) the infectious agents in the order of their resistance to chemicals ● endospores are the most resistant, enveloped viruses are the least resistant ● Most to least ○ Prions (have to be burned to kill) ○ Bacterial endospores (most resistent entity or infectious agent) ○ Mycobacterium ○ Staphylococcus and pseudomonas: has porines (channels present in outer membrane of gram negative) that makes it difficult to kill ○ Protozoan cysts (transmission form) ○ Protozoan trophozoites (once in body becomes active) ○ Most gram negative bacteria ○ Fungi and fungal spores ○ Non enveloped viruses ○ Most grampositive bacteria ○ Enveloped viruses 44. Name several phagocytic cells. ● Macrophages: largest phagocytes that ingest and kill foreign cells and participate in specific immune reactions ● Neutrophils: major phagocytic cells in the blood and actively engulf/kill bacteria; react early in the inflammatory response ● Monocytes: blood phagocytes that rapidly leave the circulation and mature into macrophages and dendritic cells ● Dendritic cells: relatives of macrophages that reside throughout the tissues and mononuclear phagocyte system and they are responsible for processing foreign matter and presenting it to lymphocytes 45. Define and list characteristics of antigens, which molecule is the most antigenic. What is an allergen? ● Antigen: foreign invader that the immune system responds to; phagocytic cells recognize it by the antigens’ surface molecules that are not the same as your molecules; it must be big enough for the immune system to see; PROTEINS are the MOST antigenic ● Allergen: compounds that are not harmful but the body reacts them and produce antibodies (IgE); pollen, food particles, dust mites, pet dandruff 46. Define lysosomes, phagosome, and explain what happens as the two fuse together. ● Lysosome: small organelle in phagocytic cells; inside lysosome have harsh oxidizing chemicals inside are hydrolytic enzymes which kill bacteria (lipase, protease, lysozyme, nuclease) ● Phagocytic cells are attracted to infection, they bind to it, and bring bacteria in (called phagosome when bacteria comes in)● Phagosome fuses with lysosome and results in killing bacteria which is done by exposing bacteria to a myriad of chemicals (acid bath); after they spit out the debris; how they remove infection from the body 47. Why gramnegative bacteria are generally more resistant to chemicals than grampositive bacteria? ● gram negative bacteria is more resistant because they have an extra layer membrane (outer membrane) for protection that also contains porins, which does not allow many chemicals to enter making it more difficult to kill 48. Name a specific gramnegative bacteria that is very resistant to killing by chemicals, and it is a major cause of opportunistic infections in hospitals. ● Mycobacterium 49. What does the term degranulation refer to? Which cells are capable of degranulation? Name an example of granules produced by these cells. ● Degranulation: mast cells, eosinophils, basophils have granules; when they see infection they release granules which are inflammatory; happens when you inhale dust mites or pollen or if you ingest a food you are allergic to; body responds to it by degranulation (allergic reaction) ● Granules: histamines, serotonin, bradykinin 50. Which cells are transplanted during bone marrow transplant? ● Stem cells which can turn into B cells or T cells 51. Compare different classes of antibodies. IgG, IgM, IgA, IgE ● Antibodies: proteins that recognize antigens (each antibody is specific to one antigen); when antibody and antigen bind to each other they form an immune complex which is the interaction between antigen and antibody Consequences of immune complex formation (directlyantigen/indirectlyantibody detect presence of microbes in the body): opsonization (process of coating bacteria with antigen; advantage: aids phagocytosis); neutralization (when virus/toxin enters body the antibody neutralizes it and prevents it from binding to host target); agglutination (trap bacteria in a web of antibodies and bind together which results in bacteria being immobilized and then killed); complement fixation (complement proteins bind to surface of bacteria, poke a hole, and lyse it); inactivation of toxins ● IgG: most abundant in blood; only one that crosses placenta and protects fetus from infection ● IgM: shows up first in infections; made of five antibodies bound together ● IgA: abundant in secretions (other than blood); involved in mucosal immunity (present in body fluids and protect against incoming infections) ● IgE: involved in allergies and recognizes allergens 52. What is the job of eosinophil, Tc, NK, and T helper cells ● Eosinophils: active in worm and fungal infections, allergies, and inflammatory reactions ● Cytotoxic t cells: destroy other cells like viralinfected cells, cancer cells, and cells from other animals or humans ● Natural killer cells: related to T cells but lack specificity to antigens; first killer cells to attack cancer cells and virusinfected cells● T helper cells: critical in regulating immune reactions to antigens and involved with activating macrophages by contact with infection or by releasing cytokines like interferons 53. What are the differences between plasma cells and memory B cells ● Plasma cells: fully activated cells that produce antibodies ● Memory cells: partially activated and do not become plasma cells; remember infections for the future; can last a lifetime (chickenpox) or a month 54. What is the job of the lymphoid tissues ● Collects free liquid around the body and eventually brought back to the heart and poured into the blood; like a sewer system; liquid passes through lymph nodes to detect infections 55. What is the relationship between Rh factor and hemolytic disease? ● Hemolytic disease: when the mother is Rh and the fetus is Rh+ then the mother develops antibodies against the baby's RBCs and attacks them 56. Describe how blood cell count results may be interpreted? ● Flow Cytometry measures the amount of cells a person has by attaching different antibodies to each cell and running them through the machine. ● May also use to determine if disease is present 57. What is meant by antigen processing? APC. Which cells are involved in this process? List APC’s. ● Antigen processing: a way to recognize antigen; APCs (antigen processing cells) are cells that see the antigen, recognize it, process it, then present it to T helper cells (cannot see infection directly) which become activated and active other T helper cells and release cytokines which activates other cells ● APCs: B cells, macrophages, dendritic cells 58. Define inflammation and list its major characteristics ● Inflammation: innate/nonspecific; result of body producing inflammatory compounds; results in redness, swelling, heat, and pain because all of these happen in site of injury or infection; recruitment of phagocytic cells to remove infection; inflammation results in cells leaving the lymph and blood and entering the area of infection which is called diapedesis (technique that WBCs use to leave blood vessels and go into the open to fight infection; RBCs cannot do this) Acute inflammation: quick to develop and heals quickly; beneficial Chronic inflammation: slow to develop, low grade, and lasts long; damaging 59. Compare Host vs. Graft and Graft vs. Host Hypersensitivity reactions. (Type IV) ● Graft versus Host Disease is a condition associated with a bone marrow transplant in which T cells in the transplanted tissue mount an immune response against the recipient’s (host) normal tissues. The graft rejects the host. ● In Host versus graft, the cytotoxic T cells of a host recognize foreign class I MHC markers on the surface of grafted cells, they release interleukin2 as part of a general immune mobilization (figure 14.11). Antigenspecific helper and cytotoxic T cells bind to the grafted tissue and secrete lymphokines that begin the rejection process within 2 weeks of transplantation. Antibodies formed against the transplanted tissue contribute to the damage, resulting in the destruction of the vascular supply and death of the graft.60. How fever is produced? Which molecules may induce fever? What are they called? ● Fever: produced when circulating substances called pyrogens rest the hypothalamic thermostat to a higher setting which signals the musculature to increase heat production and peripheral arterioles to decrease heat loss through vasoconstriction ● Molecules that can induce fever: pyrogens can be exogenous (viruses, bacteria, protozoa, endotoxins, fungi) or endogenous (pyrogens released by monocytes, neutrophils, macrophages) 61. Which antibody is involved in allergic reaction? What is meant by desensitization? ● IgE is involved in allergic reactions ● Desensitization occurs when IgE decreases and IgG increases 62. What are the immunosuppressive drugs? Their use? ● drugs that prevent the activity of the immune system, used when you get a severe burn, removal of spleen, when you got through radiation, ● also used to make your body less likely to reject a transplanted organ 63. Describe the role of antibodies in fluorescent microscopy. ● Antibodies are tagged with fluorescence so that when they bind to a new bacteria they can be identified. Fluorescent antibodies (FAbs) can be used for diagnosis in two ways. In direct testing, an unknown test specimen or antigen is fixed to a slide and exposed to a FAb solution of known composition. If antibodyantigen complexes form, they will remain bound to the sample and will be visualized by fluorescence microscopy, thus indicating a positive result. These tests are valuable for identifying and locating microbial antigens on cell surfaces or in tissues and in identifying the causative agents of syphilis, gonorrhea, and meningitis, among others. In contrast, FAbs used in indirect testing recognize the Fc region of antibodies in patient sera (remember that antibodies are antigenic themselves!). Known antigen (i.e., bacterial cells) is added to the test serum, and binding of the fluorescent antibody is visualized through fluorescence microscopy. Fluorescing aggregates or cells indicate that the FAbs have complexed with the microbespecific antibodies in the test serum. This technique is frequently used to diagnose syphilis and various viral infections. 64. Define agglutination and neutralization. ● agglutination: trapping bacteria in a web of antibodies until immobilized (clumping of particles) ● neutralization: the immunological sense refers to the ability of specific antibodies to block the site(s) on viruses that they use to enter their target cell. 65. Define autoimmunity. Give examples of autoimmune diseases and their targets. ● Autoimmunity is the system of immune responses of an organism against its own healthy cells and tissues. Any disease that results from such an aberrant immune response is termed an autoimmune disease. ● Examples of autoimmune diseases are: ○ Systemic lupus erythematosus (SLE) Systemic; Inflammation of many organs; antibodies against red and white blood cells, platelets, clotting factors, nucleus DNA ○ Rheumatoid arthritis and ankylosing spondylitis Systemic; Vasculitis; frequent target is joint lining; antibodies against other antibodies (rheumatoid factor), T cell cytokine damage○ Graves’ disease Thyroid; Antibodies against thyroidstimulating hormone receptors ○ Myasthenia gravis Muscle; Antibodies against the acetylcholine receptors on the nervemuscle junction alter function Type 1 diabetes Pancreas; T cells attack insulinproducing cells ○ Multiple sclerosisMyelin; T cells and antibodies sensitized to myelin sheath destroy neurons 66. What does geochemical recycling mean? What is the role of microbes in this process? ● Recycling C, N, O, S elements ● Microbes convert one form to another 67. What are the greenhouse gases? How do they contribute to the global warming? ● Greenhouse gases: CO2 and CH4 ● Contribute to global warming: control the ratio between CO2 and CO4 by fixing/using/producing it; concentration of these two gases contribute to global warming 68. What is role of microbes in C, N, O and Sulfur cycle ● Role: natural recyclers; can take carbon organic compounds and break down into CH4 or CO2 gas, take CO2 gas and convert it to CH4 or vise versa, take CO2 and convert it into organic or do that with CH4; can take nitrogen and fix it (nitrogen fixation: converting the gas into something soluble and then plants absorb it and grow; without nitrogen fixation plants would not be able to absorb it; lightening can fix nitrogen), denitrification (soluble nitrogen to gas; worst enemy of farmers because it removes nitrogen from soils); does the same for O and S 69. Define: bioreporters, biosensors, xenobiotic, and microbial leaching. ● Microbial leaching extracting metals from ore in mining (copper, magnesium) ● Bioreporters and biosensors: sense presence of toxins and chemicals in soil ● Xenobiotic: compound that never existed natural, completely manmade 70. Describe the role of microbes in treatment of raw sewage. What is BOD? ● Microbes are involved in removing ORGANIC sewage which is part of the secondary treatment; in anaerobic sludge digesters microbes digest organics and produce CH4 gas ● BOD: biological oxygen demand; the higher the organic the higher the BOD and the less oxygen that is available for others; reason you have to treat sewage before it hits the water is because you need to reduce the BOD so oxygen is not removed from the water; microbes remove BOD in secondary treatment 71. List different forms of extremophiles. What black smokers? ● Extremophiles: microbes that thrive in extreme environments ○ Thermophiles/Hyperthermophiles: heat loving microbes ○ Psychrophiles: coldloving ○ Acidophiles (ph<5) ○ Alkaliphiles (pH > 10) ○ Alkaliphiles (high sale) ● Black Smokers: found on the sea floor, expel superheated water that is rich in minerals usable by chemolithotrophs