W2 - BACTERIAL GROWTH Flashcards
3 types of classification system
Numerical classification
Phylogenetic classification
Phenotypic classification
Basis: frequency of trait-sharing (phenetics)
Numerical taxonomy
Numerical taxonomy is also called
Computer taxonomy
Has 20 biochemical tests for bacteria identification; collect/compile posi/nega reactions in the biochemical test
Analytical Profile Index (API)
ID VALUE: 32143
Enterobacter cloacae
Enterobacter sakazakii
ID VALUE: 32143 E. cloacae (Atypical test result & Confirmatory test)
Sorbitol- = -
ID VALUE: 32143 E. sakazakii (Atypical test result & Confirmatory test)
Urea+ = +
ID VALUE: 32161 (Atypical test result & Confirmatory test)
None = V-P+
ID VALUE: 32162 (Atypical test result & Confirmatory test)
Citrate- = no confirmatory test
Automated instrument for bacterial identification and antimicrobial susceptibility testing
VITEK 2
Basis: genetic similarity and evolutionary relatedness
Phylogenetic classification
3 domains of phylogenetic classification
Bacteria
Archaea
Eukaryota
Phylogenetic classification: Bacteria
(Green ProTABS PC+; 9)
Green filamentous bacteria
Proteobacteria
Thermotoga
Aquifex
Bacteroides Cytophages
Spirochetes
Planctomyces
Cyanobacteria
Gram positives
Phylogenetic classification: Archaea
(MethaTHaloP; 7)
Methanobacterium
Methanococci
Methanosarcina
T. celer
Thermoproteus
Halophiles
Pyrodicticum
Phylogenetic classification: Eukarya
(PEAS FC FT MD; 10)
Plants
Entamoebas
Animals
Slime molds
Flagellates
Ciliates
Fungi
Trichomonads
Microsporidia
Diplomonads
Basis: overall similarities
Phenotypic classification
Observable characteristics (phenotypic classification)
Microscopic characteristics
Colony morphology
Group or level of classification
Taxa/Taxon
Hierarchical system within domains (high to low)
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Basic unit of taxonomy
Species
Represents a specific, recognized type of organism; identified by comparison w known “type strains”
Species
No mixture of oth organisms
Pure culture
An organization that stores and provides standard cultures to the academe, researchers, etc.
American Type Culture Collection (ATCC)
Num of times an organism was cultured
Passage
Limit of pure culture passages
5
Population of microbes descended from a single individual or pure culture
Strain
Strains represent - within a species
Genetic variability
3 classification of strains
Biovars
Morphovars
Serovars
Differ in their biochemical and physiological characteristics
BIOVARS
Differ in morphology
Morphovars
Strains based on antigenic property or serum
Serovars
Ex. Biovars
Ureaplasma urealyticum
Ex. Morphovars
Corynebacterium diptheriae
● Coyrnebacterium mitis
● Corynebacterium intermedius
● Corynebacterium gravis
Ex. Serovars
Salmonella enterica
Escherichia coli honors -
Theodor Escherich
Main resource for determining the identity of bacteria species, utilizing every characterizing aspect
Bergey’s Manual of Systematic Bacteriology
Major elements
(MICHON PSP)
Magnesium
Iron
Calciuum
Hydrogen
Oxygen
Nitrogen
Phosporus
Sulfur
Potassium
Trace elements
(M2C2Z)
Manganese
Molybdenum
Cobalt
Copper
Zinc
Function of elements
Act as co-factors for enzymatic reactions
Phototroph energy source & 2 processes
Light
Anoxygenic (no o2 presence)
Oxygenic (w/ o2 presence)
Nutritional types of chemotroph
Chemolitotrophs
Chemoorganotrophs
Chemotroph energy source
Chemical (Inorganic chemicals and Organic chemicals)
Autotroph (Canophiles) carbon source
Co2
Heterotroph carbon source
Organic compounds
essential substances that the organism is unable to
synthesize from available nutrients
Growth factors
Required for the synthesis of nucleic acid.
Purines and pyrimidines
Required for the synthesis of proteins
Amino acids
Required for the synthesis of coenzymes and certain enzymes
Vitamins
Organisms that require a variety of growth factors to gr
Fastidious organisms
Organisms that strictly require oxygen for them to grow
Obligate aerobes
Organisms that can grow with or without the presence of oxygen; Produces ATP via
AEROBIC RESPIRATION
Facultative Anaerobes
Organisms that don’t need the presence of oxygen for them to grow
Obligate anaerobes
Organisms that do not really need the presence of oxygen for them to grow; Even with the presence of oxygen, they can still survive
Aerotolerant anaerobes
Organisms that can grow with the presence of a little amount of oxygen
Microaerophiles
Organisms that can grow with or without the presence of oxygen; Produces ATP via
ANAEROBIC RESPIRATION
Facultative aerobes
Obligate aerobes, most facultative anaerobes
Superoxide dismutase: +
Catalase: +
Peroxidase: -
Most aerotolerant anaerobes
Superoxide dismutase: +
Catalase: -
Peroxidase: +
Obligate anaerobes
Superoxide dismutase: -
Catalase: -
Peroxidase: -
Tests for streptococcus
PYR
BEA
Taxo A
Taxo B
can grow in low/cold temperatures
○ Usually 0 —20 °C
Psychrophiles
Psychrophiles known as
Psychrotrophs / Facultative psychrophiles
Psychroduric
○ 20 —45 °C
○ Almost room temperature — body temperature
○ Most pathogenic organisms
Mesophiles
Above 45 °C (hot-loving)
Thermophiles
grow beyond boiling point: 100 °C
Hyperthermophiles
Organisms that love moist environment
Humidophiles
Organisms that love dry environment
Xerophiles
Only common solute that occurs over a wide concentration range
Salt (NaCl)
organisms that are able to live in environments that are high in sugar
Osmophiles
Mild halophiles
1-6% salt
Moderate halophiles
6-15% salt
Extreme halophiles
15-30% salt
● Does not require salt in order for them to grow
● BUT can tolerate the presence of salt for their survival
Halotolerant
Movement of a SOLUTE from high concentration to low concentration
Simple diffusion
Solute combined with transporter protein in order for them to move across the membrane; needs ATP
Facilitated diffusion
Movement of WATER from an area of ↑ H2O concentration to an area of ↓ H2O
Osmosis
Pressure required to stop H2O movement across the membrane
Osmotic pressure
No net movement of water
Isotonic [isosmotic] solution
Extracellular water enters the cell that may cause the cell to burst (osmotic lysis)
Hypotonic [hypoosmotic] solution
Water molecules moves out of the cell causing it to shrink (plasmolysis)
Hypertonic [hyperosmotic] solution
Ph of most bacteria
Ph 6.5-7.5 (7.2-7.6); slightly alkaline
Ph of molds and yeasts
Ph 5-6 (acidic)
Bacteria that can grow well below optimum pH
Acidophile (pH 2-5)
Grow best in optimum pH
Neutrophile (pH 7)
Bacteria that can grow best on alkaline conditions
Alkaliphile (pH 8-9)
Range of ph which the organism cannot grow
Min ph and max ph
Binary fission process
- Cell elongates and DNA is replicated
- Cell wall and plasma membrane begin to divide
- Cross-wall forms completely around divided DNA 4. Cells separate into two
4 phases of bacterial growth curve
Log phase
Lag phase
Stationary/Plateau phase
Death/Logarithmic decline phase
Adjustment period; no growth and death of bacteria
Lag phase
○ exponential phase/exponential growth phase
○ means of replication of bacteria through binary
fission
Log phase
number of cell death is equal to number of new
bacteria produced
Stationary/Plateau Phase
All bacteria enter death phase
Death/Logarithmic Decline Phase
Causes exponential growth/ log phase to stop
Waste product accumulation
Exhaustion of nutrients
Toxin production
Harmful pH change
● The time it takes for an organism to double its number
● Time required for a cell to divide
Doubling time