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infectious disease
exam 5
Question | Answer |
---|---|
Francesco Redi | first controlled experiments challenging spontaneous generation. meat experiment |
John Needham | "a life force" produced spontaneous generation. boiling was not long enough to kill endospores of microbes |
Lazzaro Spallanzani | microbes move through the air, could be killed via boiling. critics argued that boiling destroyed the "life force in air" |
Pasteur's swan necked flask | disproving spontaneous generation. air moves in and out of flask. infusion remains sterile indefienitely. dust from air settles in bend. |
Germ theory by pasteur | defined what causes disease. many diseases are caused by the presence and actions of specific micro-organisms w/in body |
Koch major discoveries | 1. dev and use of solid media. able to isolate bacteria 2. verified "Germ theory" 3.Dev "Koch's postulates" |
Koch postulates | causal relationship b/w causative microorganism and a disease. 1. same microorganisms (MO) are present in every case of disease 2.MO iso from tissue of dead, pure culture 3. MO inoculated into healthy cause disease. 4.MO iso from experimental animal |
Dmitri Iwaniwski | extracts from diseases tobacco plants can transmit disease to other plants after passage through filters |
Karl Landsteiner and Erwin popper | poliomyelitis was caused by virus |
Felix d'Herelle | independently recognized viruses which infect bacteria, bacteriophages |
John Enders, Thomas Weller, Frederick Robbins | grow poliovirus in vitro using human tissue culture |
Kausce | dev electron microscope |
Bright field | demonstration of morphology and size of stained bacteria and fungi |
Phase-contract | examining unstained cells in suspension |
dark-field | examining unstained bacteria, protozoa, fungi |
Flourescence | ID microorganism w/ sp AB conjugated w/ fluorochromes |
Transmission electron | demonstrating viruses in biological material and demonstrating ultrastructures of other microorganisms |
scanning electron | demonstrating 3D structure of microorganisms |
Archaea | often isolated from extreme env, highly saline lakes or acidic hot spings |
Fungi | eukaryotic. have cell walls. Molds and yeast |
Mold | multicellular, filamentous growth,repro via sexual and asexual spores |
Yeast | unicellular, oval to round, reproduce by budding |
components of flagella | 1.filaments 2. hook 3. basal body differences in flagella proteins allow classification of sp in serovars |
Fimbria | movement and for adherence to each other and to env. biofilms. |
Pili (conjugation pili) | are for transfer of DNA from one cell to another. conjugation |
Gram staining procedure | 1.Crystal violet. cells stained purple 2.iodine. mordant. cells remain purple 3.ethanol and acetone.decolarized. Gpos=purple. Gneg=colorless 4.safranin= Gpos=purple. Gneg=pink |
endospores | durability and pathogenicity. high content of dipicolinic acid and Ca. resistant to drying, pasturization, radiation, disinfectants |
during endospore generation, what stage is able to cause disease | when the cytoplasmic mem grows and engulfs forespore w/in a second mem. vegetatice cell's DNA disintegrates. |
Effector proteins | enzymes (proteases and lipases), proteins acting as cytotoxis or apoptotic. Gram neg bacteria esp! |
generation time | time required for a bacterial cell to grow and divide |
How is oxygen damaging to anerobes | oxygen is highly reactive and excellent oxidizing agent. oxidization causes irreparable damage to cells |
why do microbes require water | to dissolve enzymes and nutrients. reactant in metabolic rxns |
two common isolation techniques | 1.streak plates 2. pour plates |
complex media ex | blood agar, macConkey agar, trypticase soy agar |
complex media | contain nutrients released by partial digestion of yeast, beef, soy, casein. Fastidious bacteria grow |
why is blood added to complex media | provide additional growth factors (NADH and heme) |
Selective media | contains substances for particular organism or inhibit the growth of unwanted organisms. |
examples of mobile genetic elements | plasmids, bacteriophages, transposons |
phage typing | use of well characterized lytic phages to id specific bacteria. causes lysis of bacteria. |
drugs | chemicals that affect physiology in any matter |
antimicrobial agents | drugs that treat infections. they can kill or inhibit growth of susceptible microoganism |
Paul ehrlich | "Magic bullets" arsenic compounds that killed Treponema pallidum, causative agent of syphilis |
Gerhard Domagk | Prontosil red for steptococi infections. converted to sulfanilamide in the body. |
Alexander fleming | Penicillin released from Penicillum spp. |
Selman Waksman | Antimicrobial agents produced naturally by organisms. |
Selective Toxicity | Based on differences of biochemical, structural or metabolic pathways b/w bacteria and eukaryotes. |
Mechanism of action of inhibition of cell wall syn | 1. Inhibition of cell wall 2.Inhibition of pathogens attachment to or recognition of host 3.Inhibition of protein syn 4.Distruption of cytoplasmic mem 5.Inhibition of DNA/RNA syn 6.Inhibition of met. pathways |
Inhibition of cell wall syn | Prevent cross-linkage of NAM subunits in pep layer. Beta-lactams. prevent bacteria from increasing amt of peptidoglycan. No effect of existing pep layer. Weakened cell wall=lysis |
Examples of beta lactams | 1.Penicillins 2.Cephalosporins 3.Monobactams |
semi synthetic derivatives of beta-lactams | more stable in acidic env. more readily absorbed, less susceptible to deactivation, more active against more types of bacteria. |
Mechanism of action inhibition of protein syn | Drugs selectively target translation at 70s (30s and 50s). can be more toxic and have more adverse effects |
Mechanism of action disruption of cytoplasmic mem | form channel through cytoplasmic mem and damage integrity. |
Mechanism of action inhibition of Nucleic acid syn | block DNA replication or mRNA transcription. Affect both prokaryotic and Eukaryotic cells. |
Mechanism of action inhibition of metabolic pathways | effective when metabolic processes of pathogens and host differ |
Ideal antimicrobial agent | 1. readily available 2.inexpensive 3. Chemically stable 4. easily administered 5.Nontoxic and nonallergenic 6.selectively toxic against wide range of pathogens |
Resistance by bacteria acquired | 1. New mutations of chromosomal genes 2.Acquistion of R plasmid via transformation, transduction, conjugation |
Resistance to Antimicrobial drugs | 1.Produce enzyme that destroys activating drug 2.Slow or prevent entry of drug into cell 3.Alter target of drug, less binding 4.Alter metabolic chem 5.Pump antimicrobial drug out of cell before it can act |
Mutualism | Bacteria: benefit Host: benefit |
Commensalism | Bacteria: benefit Host: neither benefit nor harmed |
Parasitism | Bacteria: benefit host: harmed |
resident microbiota | are a part of the normal microbiota throughout life. mostly commensal |
transient microbiota | Remain in the body for a short period. Found in the same regions as resident microbiota. Competition from other microorganisms. Elimination by the bodys defense cells |
Opportunistic pathogens | Normal microbiota that cause disease under certain circumstances. |
Conditions that provide opportunities for pathogens | 1. severe stress 2. intro of normal microbiota into unusual site in body 3.immune suppression 4.changes in normal microbiota |
Reservoirs of infection | sites where pathogens are maintained as a source of infection |
Types of reserviors | 1.Other infected animals 2.Carriers 3.Nonliving reservoir |
Exotoxin | secreted by the pathogen. dissolve structural chemicals in the body. Help pathogen maintain infection, invade, and avoid body defenses |
5 functions of AB | 1. Neutralization 2. Opsonization 3.Oxidation 4.Agglutination 5.ADCC |