Microbial Growth Flashcards
definition of GROWTH
an INCREASE IN SIZE
in terms of MICROBIAL GROWTH–meaning INCREASE IN NUMBER
BACTERIA:
see growth on SOLID SURFACES
- colony
- biofilm
LIQUID:
- increase in # of BACTERIAL CELLS leading to TURBIDITY
definition of AUTOTROPHS
- PRODUCES their OWN FOOD
- obtains their CARBON from INORGANIC SUBSTANCES such as CARBON DIOXIDE
definition of HETEROTROPHS
- CANNOT SYNTHESIZE their OWN FOOD
- depends on OTHER ORGANISMS for FOOD/CARBON SOURCE
definition of PHOTOTROPHS vs. CHEMOTROPHS
PHOTOTROPHS:
organisms that capture PROTONS in ORDER to ACQUIRE ENERGY–SUNLIGHT is MAIN ENERGY SOURCE
CHEMOTROPHS:
organisms which obtain energy by OXIDIZING ELECTRON DONOR–OXIDIZING ENERGY of CHEMICAL COMPOUNDS is MAIN ENERGY SOURCE
definition of PHOTOAUTOTROPHS vs. CHEMOAUTOTROPHS
PHOTOAUTOTROPHS:
- uses LIGHT as ENERGY SOURCE
- uses CAROBON DIOXIDE as CARBON SOURCE (INORGANIC SUBSTANCES)
CHEMOAUTOTROPHS:
- uses CHEMICALS as ENERGY SOURCE
- uses CARBON DIOSIDE as CARBON SOURCE (INORGANIC SUBSTANCES)
definition of PHOTOHETEROTROPHS vs CHEMOHETEROTROPHS
PHOTOHETEROTROPHS:
- uses LIGHT as ENERGY SOURCE
- uses ORGANIC COMPOUNDS from OTHER ORGANISMS
*example–CHLOROFLEXUS (THERMOPHILE)
CHEMOHETEROTROPHS:
- uses CHEMICALS/CHEMICAL REACTIONS as ENERGY SOURCE
- uses ORGANIC COMPOUNDS from OTHER ORGANISMS
*example–most bacteria fall into this category (such as PROTOZOA, FUNGI, and ANIMALS)
AEROBES
- REQUIRES OXYGEN
- use of TERMINAL ELECTRON ACCEPTOR (helps with breakdown and growth)
*EXAMPLE–PSEUDOMONADS
OBLIGATE ANAEROBES
- requires TERMINAL ELECTRION ACCEPTORS OTHER THAN OXYGEN
- **STRICT REQUIREMENT–OXYGEN IS POISONOUS TO THEM!!!
*EXAMPLE–CLOSTRIDUM
FACULTATIVE ANAEROBES
- both considered to be AEROBIC and ANAEROBIC
- uses OXYGEN when PRESENT but can STILL GROW WITHOUT
- EFFICIENCY BEGINS TO DECREASE WITH ABSENCE OF OXYGEN
*EXAMPLE: E. COLI
SOD +
CATALASE +
AEROTOLERANT
- grows ANAEROBICALLY or AEROBICALLY
- OXYGEN has NO EFFECT
- emplyts ENZYMES for DETOXIFICATION of OXYGEN
*EXAMPLE–LACTOBACILLUS SPP.
SOD +
CATALASE -
MICROAEROPHILES
- grows only AEROBICALLY
- has VERY LOW OXYGEN CONC.
- *EXAMPLE–H. PYLORI
describe OXYGEN and OXYGEN SPECIES + which ENZYMES help with DETOXIFICATION?
OXYGEN
- steals ELECTRONS
- has FOUR REACTIVE OXYGEN SPECIES (known as ROS
- SINGLE O2
- CAROTENOIDS - SUPEROXIDE RADICAL O2
- SUPEROXIDE DISMUTASE - PEROXIDE ANIONS O2 (2-)
- CATALASES (water and oxygen)
- PEROXIDASES (water and NAD+) - HYDROXYL RADICALS (OH-)
- GLUTATHIONE PEROXIDASE (GPx)
describe SINGLET O2
- normal MOLECULAR OXYGEN that has been BOOSTED to a HIGHER ENERGY LEVEL
- REACTIVE towards ORGANIC MOLECULES–causes PHOTO DAMAGE
- present within PHOTOTROPHS
- quenched by CAROTENOIDS
describe SUPEROXIDE RADIAL O2-
- formed in SMALL AMOUNTS during NORMAL RESPIRATION
- TOXIC to CELLULAR COMPONENTS
- is an AEROBIC ORGANISM and PRODUCES an ENZYME (SUPEROXIDE DISMUTASE)
describe PEROXIDE ANIONS O2 (2-)
- specific H2O2 REMAINDERS from SODs
- TOXIC
- enzymes of CATALASES and PEROXIDASES
describe HYDROXYL RADICALS (OH-)
- an INTERMEDIATE FORM OF OXYGEN
- formed in SMALL AMOUNTS during NORMAL RESPIRATION but they are TRANSIENT
what are the PHYSICAL FACTORS that AFFECT GROWTH?
specific conditions that can PERMIT or INHIBIT GROWTH
- OSMOLARITY
- TEMPERATURE
- PH
describe TEMPERATURE and the EFFECTS OF TEMPERATURE
GROWTH TEMPERATURES:
- MINIMUM GROWTH
- MAXIMUM GROWTH
- OPTIMUM GROWTH
EFFECTS OF TEMPERATURES:
- PROTEIN STRUCTURE
3d vs. DENATURATION
- CELLULAR CONFIGURATION
can melt or become more loose–cannot control what’s going in or out
what are the types of GROWTH TEMPERATURES?
MINIMUM GROWTH TEMP:
- the LOWEST TEMP at which MICROBE CAN CONDUCT METABOLISM
OPTIMAL GROWTH TEMP:
- OPTIMAL GROWTH RATE
MAXIMUM GROWTH TEMP:
- HIGHEST TEMP at which MICROBE can CONDUCT METABOLISM
describe the types of MICROORGANISMS contrasted with their relate environments of TEMPERATURE (4)
PSYCHROPHILES:
- COLD LOVING (5 - 20 degrees, optimal growth 15)
MESOPHILES:
- MODERATE TEMP LOVING
- optimal; 25-40
- the MOST COMMON
THERMOPHILES:
- HEAT LOVING (50-60)
- CANNOT GROW below 45
HYPERTHERMOPHILES:
- EXTREME HEAT LOVING
- seen often in hot springs or volcanoes
- HIGHEST TEMP RECORDED–121
describe pH
- specific SCALE
PROTEIN STRUCTURE:
- 3D vs. DENATURATION
types of BACTERIAL GROUPS:
ACIODPHILES:
- obligates
- acid-tolerant
ALKALINOPHILES
*can often buffer within media
describe OSMOTIC PRESSURE
- where MICROORGANISMS obtain nutrients from WATER–water here is the SOLVENT
- have OSMOTIC EFFECTS:
- ISOTONIC; no net movement
- HYPOTONIC; water moving IN–cause of SWELLING (osmotic lysis)
- HYPERTONIC; water moving OUT–cause of SHRINKING (plasmolysis
describe types of MICROORGANISMS contrasted their related environments of OSMOTIC PRESSURE
EXTREME HALOPHILES/OBLIGATE HALOPHILES:
- requires around 30% SALINITY
- found in the DEAD SEA or GREAT SALT LAKE
- can see sometimes in saline solution for inoculating loops
FACULTATIVE HALOPHILES:
- MORE COMMON–DOES NOT REQUIRE HIGH SALT CONC
- around 2 - 15&
isotonic solution
0.9% salinity
what are BIOFILMS?
a THIN SLIMY LAYER OF BACTERIA that ADHERE to a SURFACE
- begins from a FREE SWIMMNG FORM that then ATTACHES to SURFACE
- begins to SECRETE an EXTRACELLULAR COATING–covers the bacteria
describe BIOFILMS’ STRUCTURE and SIGNALING
- has a 3d STRUCTURE
- has INTERDEPENDENCE; CELL to CELL SIGNALING known as QUORUM SENSING (cells begin to COORDINATE in response to ENVIRONMENTAL STIMULI
- bacteria begin to MIMICK MULTICELlUlAR + PREFORM COMPLEX TASKS
- formation of a FUNCTIONAL COMMUNITY
- creation of PROTECTIVE SYSTEMS
what are BIOFILM’s role within the HUMAN BODY? are there any CONCERNS?
HUMAN BODY:
(POSITIVE ROLE) - lines our INTESTINAL and RESPIRATORY SYSTEM
(DETRIMENTAL EFFECTS)
- PLAQUES on TEETH–DECAY
- WOUND INFECTIONS
**PSEUDOMONAS AERUGINOSA–forms in AIRWAYS of PATIENTS with CYSTIC FIBROSIS–creation of CHRONIC + FATAL LUNG INFECTIONS
CONCERNS:
- have HIGH ANTIBIOTIC RESISTANCE
- deep layers of biofilm have LESS METABOLIC ACTIVITY–LESS SUSCEPTIBLE TO ANTIBIOTICS
- greater protective CELLULAR COATING
- increased production of PUMPS that EXTRUDE ANTIBIOTICS
definition of CULTURE MEDIA
nutrient material used to GROW BACTERIA in a LAB
types of media we have
solid (plates) and liquid (broth)
what are the MEDIA CONTENTS and describe types of SOLID MEDIA
- media can various types of nutrients DEPENDING on what we think is a GOOD SOURCE OF NUTRITION for the number of DIFFERENT BACTERIA
SOLID MEDIA:
- AGAR
made of COMPLEX POLYSACCHARIDE and CELL WALLS of RED ALGAE
- MICROBES CANNOT DIGEST AGAR :)
- can DISSOLVE at over 100 C
(keeps nutrients INTACT–used for THERMOPHILES
- begins to SOLDIFY below 40 C
(safe for additives–most bacteria can withstand temp)
types of media types (chart)
- DEFINED
EXACT COMP is KNOWN - COMPLEX
contains DIGESTIVE PRODUCTS from YEAST, BEEF, SOY, or MILK - SELECTIVE
has COMPOSITION FAVORS ORGANISMS or INHIBITS UNWANTED ONES - DIFFERENTIAL
allows for COMPARISION and CONTRASTS ORGANISMS GROWN
describe the STEPS of BINARY FISSION
STEPS:
1. DNA is first REPLICATEd and ATTACHED to CELL MEMBRANE
2. CELL ELONGATES
3. NEW CELL MEMBRANE FORMS MIDLINE
4. CELL SEPARATES or remains ATTACHED as SEPARATE ENTITIES
defintion of GENERATION TIME (DOUBLING TIME)
the time it tales to go from ONE CELL to TWO
describe the GROWTH CURVE PHASES
- LAG PHASE
- the ADJUSTMENT TIME; cells here are beginning to just GEAR UP
- number of cells DOES NOT CHANGE - LOG (EXPONENTIAL)
- BACTERIA STARTS to GROW and DIVIDE
- ACTIVE DIVISION = NUMBER OF CELLS INCREASING - STATIONARY
- NUTRIENTS ARE NOW DEPLETED–waste products are starting to ACCUMULATE
- CELL DEATH = CELL RENEWAL
- the METABOLISM starts to SLOW DOWN and PRODUCTS important for survival - DEATH (DECLINE)
- MORE WASTE BUILD-UP
- making TOXIC ENVIRONMENT–DEATH
s. aureus and VIRULENCE FACTORS
initiates production of ENZYMES that break down HUMAN TISSUE to CLEAR WAY for BACTERIA to SPREAD
what are the WAYS TO MEASURE GROWTH?
DIRECT:
(WITH INCUBATION)
- PLATE COUNTS
- MEMBRANE FILTRATION
- MOST PROBABLE NUMBER
(WITHOUT INCUBATION)
- MICROSCOPIC COUNTS
- ELECTRONIC COUNTS
INDIRECT:
- TURBIDITY (MOST COMMON)
- METABOLIC ACTIVITY (measure pop. metabolic activity–certain METAOLIC PRODUCT is in DIRECT PROP. to NUMBER OF BACTERIA)
- DRY WEIGHT (used for FILAMENTOUS BACTERIA/MOLD, BROTH CULTURES, and DESSICATED/WEIGHED)
- GENETIC (PCR)
what do SERIAL DILUTIONS determine?
determines COLONY FORMING UNITS (CFUs)
describe MOST PROBABLE NUMBER (MPN)
MPN:
a STATISTICAL METHOD that is BASED ON DILUTIONS
- often used for WATER and FOOD SAMPLES
- series of 2 DILUTIONS and 5 REPLICATES
- depends on BACTERIAL GROWTH and DETECTS GROWTH on TURBIDITY
- will then use COMPARISION vs. TABLE
describe MEMBRANE FILTRATION
- used for LOW DENSITY/CONCENTRATION POPULATIONS
- use of LARGE LIQUID VOLUMES and poured onto a MEMBRANE–and begins to retain cells through FILTER (pore size < cell size)
- MEMBRANE is then transferred and incubated
describe MICROSCOPY COUNTS
use of MICROSCOPE and CELL-COUNTER known as the PETROFF-HAISSER COUNTING CHAMBER
- begins to CALCULATE BACK AVERAGE # of CELLS PER SQUARE
LIMITATIONS:
- need at least 10 MIL of cells/mL
- CELL VIABILITY–cannot distinguish between dead and live cells
describe ELECTRONIC COUNTER
use of CURRENT INTERRUPTION through a GLASS CHAMBER
- use of a COULTER COUNTER;
cell enters glass and begins to change electrical resistance
- has CELL VIABILITY
- if culture is too DENSE–can be INACCURATE
describe TURBIDITY
looking at how CELL GROWTH CHANGES DENSITY within LIQUID
- measuring percent light VIA the SPECTROPHOTOMETER
- lookst at TRANSMISSIOn and ABSORPTION
