Lab Quiz 9: Gram Positive Cocci Biochemistry, Microbial Symbioses, and Wastewater Treatment (Bio 286 - Microbiology) Flashcards
mannitol salt agar
selective and differential media; contains 6.5% NaCl, phenol red dye, and mannitol…. microbes that are able to grow may ferment mannitol or not (if they do, the acids they produce turn the indicator dyes in the media yellow)
mannitol salt agar (MSA) growth positive result
GROWTH
mannitol salt agar (MSA) growth negative result
no growth
mannitol salt agar (MSA) fermentation negative result
red
mannitol salt agar (MSA) fermentation positive result
YELLOW
catalase
enzyme that decomposes hydrogen peroxide to water and oxygen gas– when H2O2 is placed on the microbes, the production of bubbles indicates a positive reaction
catalase (H2O2) negative result
no bubbles
catalase (H2O2) positive result
BUBBLES
EF broth
media containing a fermentable sugar (glucose) and an acid indicator (bromcresol purple)– glucose fermentation results in acid end products, which cause the media to turn yellow… the media also contains a metabolic poison sodium azide, allowing only azide-resistant microbes to grow
EF broth negative result
purple
EF broth positive result
YELLOW
NaCl broth
contains 6.5% NaCl, allowing only halotolerant microbes to grow and turn the media cloudy
NaCl broth negative result
clear
NaCl broth positive result
CLOUDY
bile esculin slant
media used to detect the metabolism of a compound called esculin– if it is converted to esculetin, it will react with iron in the media and turn completely black… bile acids in this media inhibit the growth of most gram positive organisms
bile esculin (BE) slant negative result
tan
bile esculin (BE) slant positive result
BLACK
bile esculin (BE) slant positive result
BLACK
DNase
breaks down DNA to nucleotides by adding HCl to the DNA plate after microbes have been cultured– the low pH causes DNA to precipitate within the media, turning the late cloudy. any areas where DNA has hydrolyzed will not precipitate, leaving clear areas around growth of positive cultures
DNase (HCl) negative result
no clearing
DNase (HCl) positive result
CLEARING
sheep blood agar
some bacteria break down blood cells using toxins called hemolysins… resulting in three patterns of hemolysis clearings- alpha, beta, and gamma… additionally, bacitracin and optochin are antibiotics used to determine susceptibility
alpha hemolysis
partial breakdown of red blood cells– resulting in smoky green color (no longer red but no clearing)
beta hemolysis
complete breakdown of red blood cells, resulting in complete clearing– can read text through the plates
gamma hemolysis
no clearing, the plates have growth on them but are just as red
hemolysis results
alpha (A), beta (B), or gamma (G)
bacitracin
an inhibitor of peptidoglycan biosynthesis that group A streptococci are particularly susceptible to
bacitracin negative result
no zone (R)
bacitracin positive result
ZONE (S)
optochin
a copper containing compound that pneumococci are particularly susceptible to
optochin negative result
no zone (R)
optochin positive result
ZONE (S)
competition
a contest between organisms for territory, a niche, or resources; neither organism fully thrives as both are somewhat harmed; example: soil bacteria for carbon sources
cooperation
process of groups of microbes working or acting together for their common/mutual benefit; both organisms can benefit from this interaction; example: quorum sensing
predation
interaction where a predator (an organism that is hunting) feeds on its prey (the organism that is attacked); predator benefits but the prey does not; example: Paramecium consuming bacteria
mutualism
relationship between two organisms in which individual benefits from the activity of the other; example: lichen, ruminants, and alfalfa
commensalism
class of relationships between two organisms where one organism benefits without affecting the other; example: many members of the human microbiota that benefit from humans but the humans do not benefit
amensalism
an interaction where an organism inflicts harm to another organism without any costs or benefits received by the actor; example: antibiotic production by a fungus
parasitism
interaction where one species (the parasite) benefits at the expense of the other (the host); example: bacteriophage T4 (and all viruses in general)
three main functions of the wastewater plant
- physical removal of large and undesirable objects -> 2. Biological and/or chemical removal of excess organic material -> 3. disinfection to reduce the number of potential pathogens
head works
facilities where wastewater enters a wastewater treatment plant
screw pumps
efficient means of lifting large quantities of water or wastewater at low heads
grit and grease removal
Horizontal flow velocity is reduced to allow heavy particles to settle while grease and other floating substances are allowed to rise to the surface to be separated. An aeration system is utilized to keep the majority of organic materials in suspension during this process.
aeration basins
Aerobic bacteria and protists consume organic material of wastewater
equalization basin
maintain a constant volumetric flow of wastewater from pretreatment to other downstream operations
FeCl3 addition
remove impurities in water and for wastewater treatment.
clarifiers
Tanks that allow solids in the water to settle to the bottom
UV irradiation
another disinfection method for destroying disease-causing organisms in wastewater effluent in onsite wastewater treatment systems; destroys the genetic material of microorganisms which prevents them from reproducing.
sludge thickener
to concentrate the solids, thus reducing the volume of sludge.
aerobic digesters
The activated sludge from the final clarifiers comes here and is reduced by cannibalism.
sludge storage
any combination of drying beds, lagoons, separate tanks and pad areas to store liquid, dewatered or dried sludge
