Lab Quiz 3: Acid-Fast Stain, Bacterial Motility, Protozoa, and Fungal Slide Culture (Bio 286 - Microbiology) Flashcards
(Kinyoun) acid-fast stain
differential stain; differentiates acid-fast bacteria (pink) from non-acid-fast bacteria (blue)
Kinyoun acid-fast stain process
- primary stain - basic fuchsin… 2. mordant - phenol… 3. decolorizer - acid alcohol… 4. secondary stain - methylene blue
(Kinyoun) primary stain/mordant
basic fuchsin - phenol (15 minutes)
(Kinyoun) decolorizer
acid alcohol (10 seconds)
(Kinyoun) secondary stain
methylene blue (1 minute)
appearance of acid-fast cells after basic fuchsin / phenol
colorless -> red
appearance of acid-fast cells after acid alcohol
red
appearance of acid-fast cells after methylene blue
RED
appearance of non-acid fast cells after basic fuchsin / phenol
red
appearance of non-acid fast cells after acid alcohol
colorless
appearance of non-acid fast cells after methylene blue
BLUE
Kinyoun technique
a method of acid-fast staining that does not use heat; “cold” method of staining
mycobacterium
tuberculosis (TB) and leprae (leprosy); smegmatis (nonpathogenic, normal microbiota of skin)
mycolic acids (wax)
prevents most stains from binding, so acid-fast staining procedure is utilized
flagella
external bacterial structures that enable motility in liquid media; moving cells by rapidly rotating and providing thrust; structures that are very thin and fragile
monotrichous flagella
single flagellum at one end
amphitrichous flagella
two flagella with one at each end
peritrichous flagella
flagella that cover the surface of a cell
lophotrichous flagella
multiple flagella at one end
motility
flagella are thin “electric motors” that spin; need to be “thickened” like eyelashes with mascara to be viewed
swarming motility
coordinated propulsion involving a group of bacteria moving together via flagella
protozoa
single-celled, non-photosynthetic, primarily free-living organisms… do not posses a cell wall, but are covered with a pellicle
pellicle
series of flexible protein strips that maintains the protozoan cell’s shape and provides strength while remaining flexible
polymorphic
protozoan life cycle has more than one stage
cyst
infective form/resting form of a pathogenic protozoa; is resistant to heat, acid, and drying (but less so than an endospore)
trophozoite
the active form of a pathogenic protozoa once its cyst form is ingested; the stage in which it will grow and reproduce and form cysts under unfavorable conditions
pleomorphic
protozoa have more than one trophozoite form
polyphyletic
the protozoa are split amongst many different groups that are only distantly related genetically, as in the past they were classified based on their mechanism of motility (amoeba, ciliates, flagellates, and nonmotile)
amoebozoa
organisms that move using pseudopodia (“false feet”), namely the amoeba; reproduce by binary fission and feed by engulfing their prey with their pseudopodia; pathogenic sarcodine: entamoeba histolytica
cercozoa
group of amoeba that differs by having a calcium carbonate shell (called a test)
plasmodial slime molds
related to amoeba
alveolata
organisms possessing a complex cortical structure containing alveoli, extrusomes, and a microtubule framework
ciliphora
alveolata organisms that move using cilia (“eyelashes”); most are free living (inclduing Paramceium and Didinium) which are common inhabitants of pond water; reproduce asexually by longitudinal binary fission; contain two nuclei – macronucleus containing several active copies of chromosomes (used for growth and metabolism) and micronucleus containing one quiescent copy of chromosomes (used during genetic exchange); in sexual reproduction the two ciliates fuse in a process called conjugation where micronuclei are exchanged; only parasitic ciliate: balantidium coli (largest protozoan found in gut)
apicomplexans
alveolata organisms; nonmotile protozoa; obligate parasites; characterized by several organelles at one tip of cell; includes Plasmodium (causative agent of malaria) and toxoplasma and sarcocystis
discicristata or euglenozoa
members of mastigophora - organisms that move using a flagellum (“whip”); reproduce by lateral binary fission or a complex sexual cycle involving two different hosts; have a deep oral groove and possess disk-shaped mitochondria; hemoflagellates affect circulatory system of infected humans (including Trypanosoma and Leishmania); sexual cycles of these parasites occurs in an insect or arthropod vector so when a carrier bites a human the blood stream is infected
excavata
organisms that do not have mitochondria; including important pathogens such as giardia lamblia; normally infects through ingestion of infective cysts where the trophozoite form will emerge and reproduce once the cysts reach the intestine, causing diarrhea; during growth some cells re-cyst and are passed back into environment with feces (while few living trophozoites remaining in fecal matter quickly dying upon removal from intestine); trichomonas vaginalis causes vaginal infections (with no cyst stage, directly transmitted trophozoite through physical contact)
microsporidia (opisthokonta)
non-motile protozoa; potential pathogens lack both microtubules and mitochondria; thought to be more related to fungi rather than protists (like oomycetes)
protozoa characteristics
aquatic organisms; apex predators; single cell; no cell wall; motile
Entamoeba histolytica
of Sarcodina; Causative agent of amoebic dysentery, a severe diarrheal disease associated with ingestion of contaminated food or water; viewed on 100x magnification
Balantidium coli
of Ciliophora; The only ciliate human pathogen, these cells are transmitted by fecal contamination; viewed on 4x/10x magnification
Trichomonas vaginalis
of Mastigophora; only has Trophozoite form;Causes vaginitis and is an example of a sexually transmitted protozoan; viewed on 40x magnification
Giardia lamblia
of Excavata; Giardia has a much reduced (nearly absent) (lost) mitochondria. Causes diarrheal diseases; viewed on 100x magnification
Plasmodium falciparum
of Apicomplexans; The ring stage trophozoite can be seen in some red blood cells of malaria infected organisms; viewed on 40x magnification
fungi
group of eukaryotic microbes that can exist as single-celled or multicellular forms; cell wall is composed of chitin (type of polysaccharide); fungal membrane uses ergosterol (reinforcing agent)
yeast
single celled fungi
molds, mildews, mushrooms
multicellular fungi forms
saprophytes
vast majority of fungi live by decomposing dead organisms; secrete exoenzymes to break down larger molecules before transporting smaller subunits into cells
mycoses
fungi that can cause infections, but usually limited to skin infections (systemic infections are rare but usually fatal)
kingdom fungi divisions
chytridomycota, zygomycota, ascomycota, basidiomycota
mycologists
scientists who study fungi
hyphae
filamentous structure of multicellular fungi; main mode of vegetative growth; collectively called a mycelium
septate
hyphae that are divided into cells by internal cross walls; usually perforated by pores large enough for organelles to flow between cells
coenocytic
aseptate hyphae; hyphae are not partitioned by septa internal cross walls
fungi characteristics
terrestrial; single celled (yeast) or multicellular (mold); cell wall is made of chitin; cell membrane contains sterol called ergosterol
lactophenol cotton blue
stains fungal cell walls blue
Fusarium verticillioides
member of the class Ascomycetes and has septate hyphae; filamentous fungus widely distributed on plants and in the soil; “football-shaped” macroconidia; may cause various infections in humans – opportunistic mycoses.
Penicillium chrysogenum
member of the class Ascomycetes and has septate hyphae; filamentous fungus that is widespread – it can be found in soil, decaying vegetation, and the air; conidia form on finger-like projections; may cause infections, particularly in immunocompromised hosts; fungus that produces the antibiotic penicillin.
Rhizopus stolonifer
member of the class Zygomycetes and has coenocytic hyphae; cosmopolitan filamentous fungus found in soil, decaying fruit and vegetables, animal feces, and old bread (black bread mold); common contaminants, but can also cause occasional serious (and often fatal) infections in humans; some species are plant pathogens.
Syncephalastrum racemosum
member of the class Zygomycetes and has coenocytic hyphae; filamentous fungus that is commonly isolated from soil and animal feces particularly in tropical and subtropical areas; heterothallic fungus that requires a mating strain to produce zygospores; commonly considered as a contaminant and very rarely associated with human disease.
