Micro Exam 3
-yes, but will be decolorized by acid alcohol
Are non-acid fast cells stained by carbol fuchsin?
-see a doctor to get a diagnosis and perscription -these fingernail abnormalities can indicate other metabolic conditions or chronic diseases
Case file: Can you treat this yourself with an over the counter drug, or do you need to see a physician?
-fungal infection of the fingernail -called onychomycosis, caused by dermatophytes that can survive on keratnized tissue -artificial nails can predispose you to fungal infections -if pockets are left between artificial and real nail, then they can trap moisture and provide favorable environments for fungal growth
Case file: What disease do you suspect? Explain why.
-surface mycoses: athletes foot, jock itch and ringworm -restricted to body's surfaces and are difficult to resolve -can digest keratin and superficial layers of the skin
Case file: What other conditions are caused by dermatophytes? What is special about them that makes capable of thriving in their anatomical niche on their hosts?
-must verify that fungi are present in that area -can use microscopy of nail scraping -potassium hydroxide screen, culture, histological examination of a biopsy sample
Case file: What would you suggest be done for a more definitive diagnosis?
-depends if the fungal infection is in its mildest form->can be cured with antifungal drugs or even tea tree oil -still, it is best to see a doctor to obtain a certain diagnosis -treatment must continue for at least 3 months, sometimes 12 months to ensure destruction of dormant fungal forms in nail tissue
Case file: You see cures for this condition mentioned on TV and on the Internet-do you think they work?
1. Obtain a slide. Put tape on the top corner of the slide and draw a circle with a sharpie on the bottom, middle of the slide. 2. Obtain your organism, loop, needle, a compound light microscope and a bunsen burner. 3. Flame the loop thoroughly and cool it. Add a THIN LAYERED drop of water on the middle of the circle you drew. Flame the loop again to decontaminate it. 4. Flame the needle thoroughly to decontaminate, and cool on the agar of the test tube. Take a SMALL culture using the needle and mix it with the drop of water on the slide. Flame the needle again to decontaminate it. 5. Air dry the slide by placing it on the light source of the microscope for 10-12 minutes or longer if not dry. 6. Heat fix by waving the slide through a bunsen burner thrice. 7. Stain circle with crystal violet dye for 30 seconds. 8. Rinse with dye off the slide with distilled water. 9. Add iodine to the circle for twice as long as the crystal violet (1 minute). 10. Rinse again with distilled water. 11. Decolorize with alcohol until the runoff is clear. 12. Rinse again with distilled water. 13. Counterstain with safranin for 2-3 minutes. SHAKE BEFORE USING IT. 14. Rinse again with distilled water. 15. Blot dry with bibulous paper gently. 16. Examine under light microscope, starting with the lowest objective and progressing towards the highest objective using oil immersion. -interpreted by color and also some arrangement (rod/cocci) will give hints
Describe the gram stain procedure as done routinely in a clinical lab. How is the gram stain interpreted?
-YES -oxidation is loss of electron/hydrogen ions/protons, reduction is gain of electrons/hydrogen ions/protons -oxidative phosphylation has less to do with oxygen and more to do with ELECTRON FLOW -use different electron acceptors for anaerobes b/c of no oxygen->nitrate, sulfate, carbonate, thiosulfate, others
Do anaerobic bacteria perform oxidative phosphorylation? What are the different electron acceptors?
-fruiting bodies->diploid zygospores (produced by zygomycetes) and sporangium are dominant -biochemistry limited (except carb fermentation) -zygospores->sporangium->spores->hyphae -can identify these on physical characteristics
How are fungi identified?
-analyzes end products, enzymes present, substrates utilized -E. coli differentiated from enterobacter via IMViC test -IMViC stands for indole, methyl red (IM), voges proskauer, citrate (VP, C) -E. coli is positive for MR and I, negative for VP and C -Enterobacter is negative for MR and I, positive for VP and C
How can metabolism by measured by biochemical profile?
-physical/chemical methods->i.e. heat -inhibits key enzymes, protein denatures, and inhibition of metabolic pathways via antibiotics -autoclaving->125 C w/ 15 PSI will inactive any organism (except prions)->denatures proteins -can store in cold freezer to slow down metabolic activity -sulfa drugs (for UTIs) inhibit PABA production->effects enzyme producing folic acid->lack of nucleic acids and organism can't divide
How do methods of control help determine infection?
-C. Diff is definitively identified by detecting isocaproic acid in feces->metabolic thumbprint of C. diff->bypass culture/isolation -anaerobes identify by gas chromatography detection of end products
How do volatile end products determine infection?
-image is reversed and upside down/enlarged when looking through microscope -oil immersion has same refractive index as glass, so increase amount of light reaching objective enhances visualization
How does light behave? Why is oil immersion essential to microscopy?
-diseases associated with homeostasis disturbances, metabolic activity->leads to sepsis/septic shock -arterial blood gases, vital signs, blood pH, etc.
How does patient presentation help determine infection?
-halitosis, body odor, rotting meat, decubitus ulcers ARE ALL RESULTS OF END PRODUCTS OF MICROBIAL METABOLISM -infections associated with distinct odors produced by volatile end products->triggers sensory nerves -fresh fish doesn't smell rotten, but rotten fish stinks->due to trimethylamine oxide and anaerobic respiration -also gas gangrene
How does smell/odor represent infection?
-it is true because light helps initiate photosynthesis of plants as primary producers -sun dominates existences -climate, circadian rhythms, pigmint and mood (seasonal affective disorder) is established by exposure to sun
Is this statement true: Life is a tiny electric current driven by the sun. Why or why not?
-True -a typical TB workup is slow growing->can take weeks -mycolic acid around cell wall makes it harder to get nutrients in
True or false: the presence of a single acid fast bacterium in sputum (spit/loogy) in a patient with appropriate symptomology is enough to confirm a TB diagnosis. Why?
-first antibody produced is IgM, second is IgG ***these levels determine if infection is recent or not and establish a timeline -if more IgM than IgG->recently infected -if more IgG than IgM->not recently infected -i.e. IgM titer: 1:32, IgG titer: 1:2 (1:32 indicates more recently infected)
What are IgM and IgG titers?
-lack a cell wall -produced by antibiotic action -wall may reform -associated with SBE: subacute bacterial endocarditis->lining of the heart -heart dysfunction requires a treatment of both beta lactam and aminoglycosides
What are L forms?
-differential stain -they resist decolorization by acid alcohol because they have waxy mycolic acid outer layer -found in mycobacterium and actinomycetes -all acid fast bacteria are gram positive
What are acid fast stains?
-tests if the initial presentation is getting better -paired sera: difference in serum titer over 10-14 days -if acute (initial) titer is 1:16, convalescent titer must be greater than or equal to 1:64 (because it is 4x greater)->signals infection -can have antibody content without infection because of vaccines or minimal exposure to bacteria
What are acute convalescent titers? Can you have antibody content without infection?
-API 20E->enterics, also enterotubes -all takes 3-5 days -end with 5 digit code to get organism name -more visual and lack antibiotic susceptibility, not like Vitech/Microscan -still need pure cultures to get identification -agglutination tests: mainly for streptococcus, latex beads attach to antibodies lead to clumping (not coagulase test)
What are alternatives to common modern practices? What is agglutination tests?
-aspergillus->not contained sporangium, they are exposed -mycelum->septate wall or non-septate wall (no wall)
What are aspergillus and mycelium?
-unusual cell structures, different in structure/physiological response -"L" forms -Rickettsia -Chlamydia -Archaea (only one that isn't infectious) -Mycoplasma
What are atypical bacterial cells? What are the atypical bacterial cells?
-how microbes are identified in lab -pure culture is essential with isolation -dominate identification of bacteria -less essential for fungi and not applicable to protozoa, viruses and worms
What are biochemical tests?
-light microscopes can't resolve anything closer than 200 nm -greater resolving power and magnification -10,000x-100,000x -detailed view of bacteria, viruses, ultrastructure, large atoms -transmission and scanning
What are electron microscopes? What are the two types?
-establishes baseline of healthy individuals at one point in time -done in sero-epidemiological surveys to establish titers in healthy, normal individuals in a population -background, or not infected, is 1:8 (for example, varies depending on disease) -1:16, then infected; 1:4, then not infected
What are single static titers?
-can evade host defenses
What are some advantages of bacteria without cell walls?
-miniaturized identification systems->rapid methodology -coupled with computer based analysis -used in small volumes 100-200 microliters, don't need test tubes -Vitech/Microscan->very expensive, but specific -Wells->tiny little holes holding 200 microliters with pure culture to add to cells and stick in Vitech/Microscan->will give identification and rapid methodology -get results in hours
What are some modern practices to identify bacteria? What are Wells?
-gram negative bacteria have less peptidoglycan content, so they do not retain primary dye -if don't add iodine, then crystal violet won't bind to specimen's cell wall so everything will be gram negative -if don't rinse with water after decolorization, excessive decolorization so gram and will appear gram negative
What are some other facts about the gram stain?
-antibody levels to a microbe indicate infection by that microbe->identification -amount of antibody levels increase over time if infected -monitor and detect infection and disease **look for a single static titer above background or look for a 4x fold or greater increase in antibody content comparing acute/convalescent titers
What are the applications of titers?
-physical characteristics->size, morphology (limited) -biochemical tests: normal lab tests -serological tests -phage typing -analysis of nucleic acids->highly specific, but tedious and laborious **vast majority of microbes have never been cultured because conditions aren't suitable for growth
What are the characteristics of identification of bacteria?
-Bacillus: anthracus (anthrax), subtilis -Clostridium: Difficile, Botulinum (botulism and botox), Perfringens (gas gangrene, diabetics), tetani (tetanus, "lockjaw") -toxins of C. botulinum and C. tetani are among deadliest toxins known to mankind->bioterrorist threat along with anthracus
What are the clostridium diseases? Bacillus diseases?
-M. tuberculosis: most important, TB/MDRTB -M. avium intracellulare: pathogen, found in AIDS -M. chelonei: pathogen, causes skin ulcers in Africa -M. leprae: pathogen, causes lepracy -M. smegmatis (found in genitalia), M. phlei aren't pathogenic
What are the different types of mycobacterium?
-carbol fuchsion (red) is primary dye -counterstain is methylene blue (blue) -acid fast bacteria are red, non acid fast are blue (because retain methylene blue) -first use carbol fuchsion, then acid alcohol to decolorize, then rinse with water, then methylene blue counterstain
What are the dyes used in acid-fast stain? What color are they?
-wavelength of radiation -magnification -resolution -contrast -size of organism
What are the general principles of microscopy?
-unaided human eye: 200 micrometers -compound light microscope: 200 nm (most widely used in microbiology) -scanning electron microscope: .4 nm -transmission electron microscope: .078 nm -scanning tunneling microscope: .01 nm -atomic force microscope: 1 nm
What are the limits of resolution for the unaided human eye? Compound light microscope? Scanning electron microscope? Transmission electron microscopy? Scanning tunneling microscope? Atomic force microscope?
-staining increases resolution and contrast by coloring specimens with stains and dyes -smear of microorganisms made prior to staining -microbiological stains contain chromophore -acidic dyes stain alkaline structures, basic dyes stain acidic structures ***determines viability
What are the main principles of staining?
1. Smell/odor as a clue 2. Definitive identification through biochemical profile 3. Volatile end products 4. Methods of control 5. Patient presentation
What are the roles of metabolism in diagnosis and treatment of infections?
1. Glycolysis->prep for ATP production) 2. Pre-Kreb's (acetyl coA) 3. Kreb's cycle (TCA)->prep for ATP production in ETC 4. Oxidative phosphorylation and Electron Transport Chain->most ATP produced here with oxygen as final electron acceptor (34-38 ATP) -NADH/FADH carry high energy reducing power from macromolecule breakdown to produce ATP
What are the stages of metabolism?
-charged particles through electron beam give internal details of organism -requires tedious preparation: dehydration and heavy metal staining (i.e. lead), cut thin sections with a diamond knife ***mainly useful when looking at viruses: can look at RNA code (Ebola has characteristic spiral structure) -scanning electron microscopes: surface features, limited, less details, same amount of preparation
What are transmission electron microscopes? Scanning electron microscopes?
-document efficacy of vaccination -protection from vaccination is based on antibody content -minimum immune titer: antibody levels greater than this indicate protected, less than aren't protected
What are vaccine titers?
-3 domains: archaea (1st), bacteria (came 2nd), eukaryotes (came 3rd) -based on RNA code and molecular biology -5 kingdoms: Animalia, Plants, fungi, protists, prokaryote -clinically: identify genus and species -different features to identify bacteria compared to animals
What did Carl Woese do? Clinically?
-STD -blindness -salpingitis->ectopic pregnancy->sterility because fallopian tube blocked
What does C. Trachomatis cause?
-pneumonia -TWAR: Taiwanese Acute Respiratory Agent -not that virulent -people with heart attacks have high antibody levels to C. pneumoniae->not definitively identified as a causative agent, but still contributes
What happens in C. pneumoniae?
-causes ornithosis (psittacosis) -from birds and bird poop -not highly fatal -can lead to pneumonia
What happens in C. psittacii?
-produces pyruvate, pathway determined by environment of organism, enzymes present, substrates available -glucose-> 2 pyruvate + 4 ATP (net 2 ATP) -glucose->glucose 6 phosphate->glucose 1, 6 diphosphate=need 2 ATP in this energonic reaction->will produce 4 ATPB and exergonic reaction in the end (give a little to get a little) -C6H12O6 + 6O2->6H2O + 6CO2 + 38 ATP
What happens in glycolysis? What is the general formula for aerobic respiration?
-produces NADH, FADH, ATP, CO2 -transition reactions with acetyl coA **produces intermediate products in synthesis/degredation of all macromolecules (along with glycolysis) -occurs in aerobic/anaerobic respiration, NOT fermentation
What happens in the Kreb's cycle?
-Enzyme Linked Immunosorbent Antibody -direct: look for antigen/organism -indirect: look for antibody
What is ELISA?
-M. pneumoniae: primary atypical pneumonia -"walking pneumonia"->can be active despite lack of lung function where normally bedridden -not as seriously ill, higher incidence to young active males (b/c walk out more)
What is M. pneumoniae?
-genitical mycoplasma -non specific urethritis, occurs in males as well -women who have this while pregnant have babies who increase in stress, including respiratory difficulty
What is M. urealitycum?
-virus that attacks bacteria -Phage typing: each strain has a specific set of phages that attack ONLY that strain->can use set of phages to identify organisms -common for S. aureus, but can be done for any bacteria having a phage
What is a Phage? Phage typing?
-used to diagnose syphilis and observe pale objects ****main advantage is to look at live organisms unstained in order to confirm diagnosis -only light rays scattered by specimen enter objective lens -specimen appears light against dark background -increases contrast and enables observation of more details
What is a dark field microscope?
-paired statement applying to an organism (either/or statements) -applied for biochemical profiles -key directs user to another pair of statements until name of organism is provided
What is a dichotomous key?
-widely used -emits visible light when exposed to UV: apple/green or dull/reddish brown color -UV light increases resolution and contrast -some cells are naturally fluorescent, others must be stained -immunofluorescence identifies pathogens and make proteins visible
What is a fluorescent microscope?
-GMS (Gomori methenamine silver) can be used to detect syphilis in infected tissue -Hematoxylin and eosin (HE)
What is a histological stain? What is GMS used for?
-capsule stain->bacteria isn't stained but background is stained -get repulsion between stain and bacteria -can identify yeast and fungal meningitis->most common clinical use of negative stains by looking for capsules -cryptococcus -flagella stain: not useful clinically
What is a negative stain? Flagella stain?
-shows living organisms -not very useful in diagnostic microbiology -"makes nice pictures," like waves that are in sync -light waves are out of phase->contrast is created -2 types: phase contrast and differential interference contrast
What is a phase microscope?
-reciprocal of the highest dilution giving a positive response on adding the appropriate antigen -i.e. have dilution of 1:2 (+), 1:4 (+), 1:8 (+), 1:16 (-), 1:32 (-) -1:8 would be the titer -1=patient's blood, including antibodies, other 7=the dilutant **more antibody you have, the more dilutant you need to have to get a titer with antigen/antibody equivalent
What is a titer?
-structural stain, not differential -difference between clostridium and bacillus->clostridium are obligate anaerobes, bacillus are facultative anaerobes
What is an endospore stain? Difference between clostridium and bacillus?
-ancient bacteria -cell walls without peptidoglycan and instead pseudomurein -include halophiles (salt lover), thermophiles (heat lover), methanogens (poisonous) -no human pathogens to date because conditions aren't appropriate for growth
What is archaea?
-cellular respiration is electron flow! -amphibolic: metabolic duality -glycolysis and Kreb's are major amphibolic pathways->function in both anabolic and catabolic reactions as key points in metabolism
What is cellular respiration? What do glycolysis and Kreb's cycle do?
-similar to rickettsia as an energy parasite -complex lifestyle with elementary and reticulate bodies -includes C. Trachomatis, C. Pneumoniae, C. Psittacii -it is asymptomatic->antibiotics in babies eyes will prevent infection just in case mother has chlamydia
What is chlamydia?
-difference between intensity of 2 objects or b/t an object and its background -important in determining resolution -staining increases contrast -use of light in phase increases contrast
What is contrast?
-indicates antibodies (antibody labeling) fluorescently labeled -antibodies are very specific and can help definitively identify an organism (genus/species) ***bypasses routine culture and isolation because its so specific -can do this in a mixed culture
What is immunofluorescence?
-magnification: ocular x objective -contrast: noting differences and detail in structures->important in gram stains and microscopical analysis (increase contrast=increase detail)
What is magnification? Contrast?
-metabolism: all biochemical reactions in an organism -life and death can be defined by metabolic activity/ATP production (catabolic/anabolic linked to ATP) -yeast viability->determined by detection of metabolic activity based on meth. blue use (colorless vs. blue) -anabolic: synthetic reactions, make new macromolecules -catabolic: degradative, breaks down molecules to ATP
What is metabolism? Anabolism? Catabolism?
-yeast viability and is critical for alcohol production -dead cells are blue, live one are colorless -methylene blues is reduced by metabolic activity in the organism b/c it serves as an artificial electron acceptor -monitoring metabolic activity means they are alive->colorless -dead->blue->methylene blue not reduced->inactive->died -i.e. hepatitis vaccine made in viable yeast (totally different than yeast infection bacteria)
What is methylene blue reduction?
-lack cell walls -contain sterols in membrane->unusual for prokaryotes, normal in eukaryotes -smallest culturable bacteria known -grows cultured on agar, embedded in media->"fried egg" appearance -infections include: M. pneumoniae, M. urealitycum
What is mycoplasma? Which diseases does it cause?
-probe microscopes: good for molecules/enzymes -confocal microscopes: not very useful
What is probe microscopy? Confocal microscopy?
-ability to see detail -R=lamda (wavelength)/2NA (numerical aperture) -the greater the resolution, the greater the detail -shorter distances lead to seeing detail better (1 mm vs. 500 mm, 1 mm is better) -limit of resolution tells you how much detail is evident -in order to see an object, organism must be larger than the limit to be seen
What is resolution?
-obligate intracellular parasites->no metabolic activity to produce ATP -rocky mountain spotted fever -associated with tick bites -lack a cell wall
What is rickettsia?
-serology: any antibody/antigen related procedure or anything having to do with blood and blood proteins 1. Latex agglutination 2. Direct Fluorescent antibody (DFA for legionella, which impacts respiratory tract) 3. Titer 4. CBC differential (complete blood culture) 5. Coagulase (look for serum with antibody to clump) 6. ELISA
What is serology? What are the types of tests that can be done?
-must look for motile treponemes -treponema pallidum=etiology of syphilis -lesion will be on mouth, genitals or anus -must take a sterile pipette and score the lesion->put on slide->see motile treponemes on dark field microscope
What is syphilis?
-establishing common language that is universal->facilitates communication and provides grouping for organisms based on similarities -can predict features of an organism based on its classification properties previously known -can sort organisms and impose order
What is taxonomy used for? Why do you classify organisms?
-used to identify gardenerella vaginallis -associated with fecal distress in females -add potassium hydroxide to cervical scraping on glass slide->distinctive fishy amine odor->identify G. vaginallis without culture b/c smell is distinct
What is the Whiff test?
-most common microscope used for clinical diagnosis -simple microscope: single lens, similar to magnifying glass, Leeuwenhook used these to observe microbes -complex microscope: many lens for magnification, light passes through specimen into objective lens, oil immersion increases resolution, 1-2 ocular lenses, condenser lens -total magnification=objective lens x ocular lens
What is the bright field simple microscope? Compound?
**gives preliminary results which provides diagnosis that can lead to treatment **patient MUST have appropriate symptomology! -can't be TB if get specimen from genitalia (i.e. that's M. smegmatis)
What is the main purpose of acid-fast stains?
-understand groups of organisms -reflect phylogenetic hierarchy ***identification now is dominated by DNA sequences
What is the modern goal of taxonomy?
-species->genus->family->order->class->phylum->kingdom->domain -fairly obvious similarities, fewer numbers, more DNA similarity with species -as get larger, large numbers, less DNA similarity
What is the order of hierarchy?
-provide contrast to increase visual detail by coloring
What is the primary objective of stains?
-mycolic acid impedes antibiotic entry->more difficult to treat -antibiotics are only active on metabolically active cells (not spores) -treatment requires 6-9 months b/c slow growing and over a long period of time->people stop taking it once they start feeling better->leads to resistance and MDRTB -triple therapy
What is treatment like for M. tuberculosis?
-triple therapy: isoniazid, rifampin and ethambutol->synergist combo -attack at three different points so resistant occurs less for all 3 simultaneously ***M. tuberculosis can survive in room air for 6-9 months -mycolic acid prevents drying out and is slow growing -BUT only 10% healthy people exposed to active TB will develop TB
What is triple therapy?
-rickettsia and chlamydia are both obligate intracellular parasites->grows in tissue/cell culture (Hela cells)->doesn't grow in agar and typical media -chlamydia and gonorrhea are global epidemics -chlamydia is the most common atypical
What is true of chlamydia and rickets? Chlamydia and gonorrhia?
-detects viability by live cells being colorless, dead are blue -mechanism is different->carry membrane transport to determine membrane functionality->excludes trypan blue -exclusion is detected because live cells can pump out trypan blue and cell will be unstained/colorless -useful because determines cell and bone marrow viability -also tissue culture cells viability->used in virus culture (ensuring tissue culture cells are viable, doesn't detect virus)
What is trypan blue exclusion?
-viability stains determine if organisms are alive or dead -viability stains are oxymoronic because stains kill specimen -2 types: methylene blue reduction and trypan blue exclusion
What is viability? What are viability stains?
-protoplasts: L forms can either reform the wall OR permanently lose the wall -synergistic combination: the sum is greater than its parts -antibiotics work together to be more effective (2+2=8/10) -decreases risk of resistance
What kind of cell walls do L forms form? What is a synergistic combination?
-TCA if aerobic (34-38 ATP, 36 average), TCA if anaerobic (2-38 ATP) -fermentation (no electron transport chain)->end products are lactate, alcohol for yeast fermentation, ATP -yeast wants to make ATP (aerobic), but less oxygen is fermentation to produce alcohol and less ATP (LESS EFFICIENT)
Where can pyruvate go after being synthesized?
-photophosphorylation (photosynthesis) -oxidative phosphorylation->all produce ATP -substrate level phosphorylation (fermentation only)->no electron transfer, occurs in glycolysis and Kreb's cycle -phosphoenol pyruvate uses ATP to make pyruvate
Which processes produce ATP?
-Serotype 2 indicates infection b/c it's 4 fold -other serotypes may indicate contact, but not infection
Which serotype infected the women with legionella who tried to commit suicide? Serotype 1-Acute: 1:28, Convalescent: 1:28. Serotype 2-Acute: 1:64, Convalescent: 1:1028. Serotype 3-Acute: 1:16, Convalescent: 1:16. Serotype 4-Acute: 1:32, Convalescent: 1:32.
-Dr. Smuck infected Patient A because they have the same Phage type -MUST LOOK FOR COMMONALITY for origin -all strains differed between patients except Dr. Smuck and Patient A
Who infected who with S. aureus? Patient A: 1,2,4,6. Patient B: 2,8,10,12. Patient C: 1,9,15,16. Patient D: 9,10,12,15. Dr. Smuck: 1,2,4,6. Nurse Diddy: 6,12,15. Orderly Homey: 1,12,9,10.
-based on characteristics in common -species: organisms that can successfully interbreed (doesn't apply to microbes as much) -binomial nomenclature (genus/species) OR 3 names (includes subspecies, RNA/flagella structure) -only 2 kingdoms, 5 kingdoms established later
Who was Carl Linneus?
1. Prevents prohibitive release of large quantities of energy that would destroy the cell 2. Maximizes efficiency and recovery of energy as contained in substrate molecules 3. Provides control and coordination of entire process designed to maximize ATP production 4. Contributes to homeostasis and survival of organisms
Why are there 3 separate/discrete steps in metabolic activity?
-to make the invisible, visible -they are below the limits of the human eye -use micrometer (um, 10^-6) for bacteria, nanometer (nm, 10^-9) for viruses -have a huge role in diagnosis in infectious diseases (must use oil immersion)
Why do we use microscopes?
-viral infection can be documented by light microscopy -can look for cytopathogenic effects (CPEs) -i.e. cell rounding vs. cell death -negri bodies->evident in light microscopy in infected tissue, indicative of rabies diagnosis
Why don't you need transmission electron microscopy to discover viruses?
-increased IgM content because it is more recent
Would a sick Lauren, who recently got her flu shot, have an increased IgM or IgG content?