Microbiology Test 3
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58 terms
Terms | Definitions |
|---|---|
 Prions | - Proteinaceous Infectious particle - Inherited and transmissible by ingestion, transplant, and surgical instruments - Spongiform encephalopathies: Sheep scrapie, Creutzfeldt-Jakob disease, Gerstmann-Sträussler-Scheinker syndrome, fatal familial insomnia, mad cow disease |
| Prions cont... | - Prions cause a conformational change of native proteins into an abnormally structured form - Meaning they cause normally proteins to change shape - And now these abnormal proteins also act as prions |
| More Prions | -This change in the conformation of the proteins can have two effects - Loss of function of the native protein - Gain in toxicity of the abnormal conformation - In addition, misfolded forms of proteins have a higher likelihood to aggregate |
| Terminology of microbial control | - Sepsis refers to microbial contamination - Asepsis is the absence of significant contamination - Aseptic surgery techniques prevent microbial contamination of wounds |
| More Terminology of microbial control | - Sterilization: Removing all microbial life - Commercial sterilization: Killing C. botulinum endospores - Disinfection: Removing pathogens - Antisepsis: Removing pathogens from living tissue |
| Even more Terminology of microbial control | - Degerming: Removing microbes from a limited area - Sanitization: Lowering microbial counts on eating utensils - Biocide/germicide: Kills microbes - Bacteriostasis: Inhibiting, not killing, microbes |
| Heat on microbes | - Heat appears to kill microorganisms by denaturing their enzymes - As a result, altering their structure |
| Moist heat sterilization | - Moist heat denatures proteins - Autoclave: Steam under pressure - 121 °C and 15 psi |
| Pasteurization | - Reduces spoilage organisms and pathogens - Thermoduric organisms survive |
| Filtration | Membrane filtration removes microbes >0.22 µm |
| Radiation | - Ionizing radiation (X rays, gamma rays, electron beams) - Ionizes water to release OH• - Damages DNA - Nonionizing radiation (UV, 260 nm) - Damages DNA - Microwaves kill by heat; not especially antimicrobial |
| Types of Disinfectants | Phenols & Phenolics (carbolic acid) Disrupt plasma membranes |
| Halogens | Iodine Tinctures: In aqueous alcohol Iodophors: In organic molecules Alter protein synthesis and membranes |
| Alcohol | Ethanol, isopropanol Denature proteins, dissolve lipids Require water |
| Heavy Metals | Denature Proteins |
| History of chemotherapy | Alexander Fleming: Penicillum notatum |
| Antimicrobial Drugs | - Chemotherapy: The use of drugs to treat a disease - Antimicrobial drugs: Interfere with the growth of microbes within a host - Antibiotic: A substance produced by a microbe that, in small amounts, inhibits another microbe - Selective toxicity: A drug that kills harmful microbes without damaging the host |
| Spectrum of Antimicrobial | Broad spectrum Narrow spectrum Superinfection |
| The action of antimicrobial | Bactericidal Kill microbes directly Bacteriostatic Prevent microbes from growing |
| Inhibitors of Cell Wall Synthesis | - Penicillin - Prevents cross-linking of peptidoglycan |
| The Structure of Penicillins | Have Beta-Lactam Ring |
| Inhibitors of cell wall synthesis | - Antimycobacterial antibiotics Isoniazid (INH) - Inhibits mycolic acid synthesis Ethambutol - Inhibits incorporation of mycolic acid |
| competitive inhibitors | Sulfonamides (sulfa drugs) Inhibit folic acid synthesis Broad spectrum |
| Antiviral drugs | - Protease inhibitors Indinavir: HIV - Integrase inhibitors HIV - Inhibit attachment Zanamivir: Influenza Block CCR5: HIV - Inhibit uncoating Amantadine: Influenza |
| Concept of Immunity | Susceptibility: Lack of resistance to a disease Immunity: Ability to ward off disease Innate immunity: Defenses against any pathogen Adaptive immunity: Immunity, resistance to a specific pathogen |
| Innate Immune system | How does the innate immune system recognize foreign materials such as bacteria? Host Toll-like receptors (TLRs) attach to Pathogen-associated molecular patterns (PAMPs) |
| The normal microbiota | - Normal Flora - These microbes are typically take permanent residence of our body Colonize - Typically do not cause disease Opportunistic pathogens |
| Formed elements in the blood | Blood consists of two parts Plasma - Fluid component Formed Elements - Cellular component Leukocytes WBC |
| Leukocytes | - Granulocytes- Contain large granules - Agranulocytes |
| Granulocytes | Neutrophils - commonly known as polymorphonuclear leukocytes (PMNs) - Highly phagocytic and motile |
| Agranuloctyes | Monocytes Mature monocytes turn into macrophages |
| Action of Phagocytic cell | - Fixed macrophages Do not leave the tissue once they enter it - Free (wandering) macrophages - Roam tissues and gather at sits of infection or inflammation |
| Action of phagocytic cells | When an infection occurs, the innate immune system is activated Phagocytic cells such as neutrophils and monocytes migrate to the infected area Migration into the infected tissue stimulates the maturation of monocytes into macrophages |
| Mechanism of Phagocytosis | Chemotaxis Adherence Ingestion Digestion |
| More mechanism of phagocytosis | The phagosome detaches from the plasma membrane and enters the cytoplasm Combines with a lysosome which contains digestive enzymes, forming the phagolysosome |
| Inflammation | Characteristics of inflammation Redness Swelling (edema) Pain Heat Loss of Function (in extreme cases) |
| The complement system | Proteins of the complement system destroy microbes by: Cytolysis Inflammation Phagocytosis - Inactive until they are split into fragments (products) |
| Dual nature of adaptive | Humoral immunity - B cells mature in the bone marrow Due to antibodies |
| Dual nature of adaptive cont... | Cellular immunity Due to T cells T cells mature in the thymus |
| The nature of antigens | Antigens are compounds that provoke a highly specific immune response Most antigens are either proteins or large polysaccharides Often components of invading microbes Capsules, Cell wall Flagella, Fimbriae Toxins Viral coat - All antigens are not components of microbes |
| The nature of antigens cont... | - Antibodies recognize and interact with specific regions on antigens called epitopes - The size, shape, and chemical structure of the antibodies binding site dictates the epitope an antibody recognizes - Hapten: Antigen is combined with carrier molecules |
| The nature of antibodies | Antibodies Globular protein Soluble proteins having a nearly spherical structures to varying degree of elliptical structure Referred to as immunoglobulin (Ig) Made as a response to an antigen, which can then bind to that same antigen |
| The nature of antibodies cont... | Antibody monomers are composed of 4 proteins 2 heavy chains 2 light chains Each antibody has at least two identical sites that bind to epitopes Antigen Binding Site |
| The nature of antibodies cont....still | There are 2 regions of an antibody The variable(V) region The constant(C) region The stem of the antibody is known as the Fc region |
| The nature of antibodies cont....even still | There are 5 classes of Igs IgG, IgM, IgA, IgD, and IgE |
| B cells and humoral immunity | B Cells Produce antibodies when activated When exposed to free or extracellular antigens Each B cell carries immunoglobulins on its cell surface Upon being triggered by an antigen The B cell divides (clonal expansion), and the daughter cells synthesize and secrete antibodies Two types of daughter cells Plasma cells - produce antibodies Memory cells - Long lived cells, responsible for an enhanced secondary response |
| B cells and humoral immunity cont... | - B cells activation typically require assistance of a T helper cell (TH) - T-dependent antigen - The antigen is enzymatically processed by the B cell into fragments which are combined with the major histocompatibility complex (MHC) - Antigens that stimulate B cells without T cells are called T-independent antigens |
| Results of Ag-Ab binding | Agglutination Ab's cause antigens to clump together or aggregate - Opsonization (Greek, to cater or prepare food) Antigen is coated with Ab's which enhances its ingestion and lysis by phagocytic cells |
| Results of Ag-Ab binding cont... | Neutralization IgG Ab's inactive a microbe by blocking their attachment sites to host cells Neutralize toxins in a similar way - Activation of Complement System IgG or IgM triggers complement activation by the classical pathway |
| Results of Ag-Ab binding cont... | Antibody-dependent cell-mediated cytotoxicity Resembles opsonization Except the target cell remains outside of the immune cell |
| T cells and cellular immunity | Clusters of Differentiation (CD) CD4+ and CD8+ TH cells are classified as CD4+ Because they bind to MHC class II molecules on B cells and Antigen Presenting Cells TC cells are classified as CD8+ cells Which bind to MHC class I molecules |
| types of adaptive immunity | Naturally acquired active immunity Resulting from infection Naturally acquired passive immunity Transplacental or via colostrum Artificially acquired active immunity Injection of Ag (vaccination) Artificially acquired passive immunity Injection of Ab |
| Types of vaccination | Attenuated whole-agent vaccines Uses live weakened microbes Most closely mimic's an actual infection Provides lifelong immunity without booster 95% effectiveness due to viral replication Examples MMR - Measles, Mumps, and Rubella Polio vaccine |
| Types of vax | Inactivated whole-agent vaccines Uses microbes that have been killed By chemicals such as formalin or phenol Examples Pneumococcal pneumonia Cholera |
| Types of vax | Toxoids Inactivated toxins Example Tetanus toxoid Diphtheria toxoid |
| Types of vax | Subunit vaccines Fragment of a microbe that can best stimulate an immune response Includes recombinant vaccines Inherently safer because they cannot reproduce in the recipient And also cause fewer adverse effects |
| Types of vax | Conjugated Vaccines Based on capsular polysaccharides Often are combined with proteins such as diptheria toxoid to improve response Examples Haemophilus influenzae type B |
| Types of vax | Nucleic Acid (DNA) Vaccines DNA is injected into muscle, resulting in the production of the encoded protein antigen Stimulates both the humoral and cellular immunity Can be delivered by a needles injection device called the "gene gun" |
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