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BMIC - Coggle Diagram
BMIC
Nutrients
essential nutrients
required for microoganisms to grow but cannot be synthesized by them thus must be provided during subculture
useful to make organic molecules and build cellular structures
Micronutrients (minute quantities)
Trace elements (Mn, V)
Growth factors
Macromolecules(large quantities)
C, N, H, O, S, P, Na, Ca, K, Mg, Fe
synthesise growth factors to grow
Can be
Organic(carbon source and growth factors)
Inorganic ( mineral salts)
Can synthesise own
prototrophs
Cannot synthesis own
Auxotrophs(mutants) (need to provide growth factors in subculture)
Carbon source
Heterotrophs
Reduced performed organic substances
Autotrophs
Carbon dioxide
Chemoheterotrophs
Photoautotrophs
Energy source
Phototrophs
Light
Chemotrophs
Oxidise organic/inorganic compounds
Culture media
Mixture of different compounds that provide all the nutrients required for microoragnisms to grow
Culture- a collection of microorganisms
Pure (1 colony)
Mixed ( more than 2 colonies)
Defined
chemical formulas (common)
Exactly duplicated
Chemical composition is known
Undefined
natural products
no chemical formulas
batch to batch variation
cannot be exactly duplicated
Water-soluble extracts
Yeast, beef and soil extract
Provides organic carbon and nitrogen content, growth factors, nucleosides and coenzymes, mineral salts, vitamins
Digests of proteins
Provides organic carbon and sulfur, amino acids, water-insoluble growth factors
Peptone, tryptone, caesin hydrolysate
Others
Blood, serum
provide complex growth factors for fastidious microorganisms
Chemical composition is unknown
Types
General
Consists of natural products
supports the growth of a wide variety of microoragnisms except fastidious ones
Nutrionally demanding
Nutrient broth/agar, soya tryptone broth/ agar
Minimal
chemically defined
The minimum amount of nutrients needed to support the growth of microorganisms
Useful for screening auxotrophic micoorganisms
To investigate the nutrient requirement for study microorganisms and define them
Selective
Contains inhibitory substances that inhibit the growth of certain microbes and favour the growth of some microbes which are not affected by inhibitory substances
e.g salty conditions and pH
Useful for rapid identification and isolation of desired microorganisms
Differential
helps to distinguish different colonies by visual differentiation and usually involve nutrient utilisation
Add pH indicator if alkali and acid are produced
Selective and differential
Functions as both
useful for identification of microoragnisms in clinical, environmental and food samples
MacConkey agar
Useful for the identification of coliforms in environment and food samples
Bile and crystal violet allows gram negative bacteria to grow
1 more item...
Mannitol salt
Differentiation of pathogenic staphylococcus from normal one in clinical sampes
thrives in salty conditions
The surrounding agar turns yellow in the presence of phenol red(due to mannitol fermentation)
Virus
Intracellular parasites
requires a living host in order for them to attach and replicate themselves
embryonated eggs
live cell/tissue cultures
Bacterial cell cultures
live plants/animals
physical states
Solid
2% v/v solidifying agents
Can grow most microorganisms except some marine microorganisms as they can catabolise agar
Can add heat labile substances/ supplements when agar is molten(45-50oC)
Pros
detect microbial contamination
useful for isolating pure cultures
Culture seens as colonies
Cons
tedious to prepare large batches
tedious to grow large quantities of cultures
Smaller yield, difficult to harvest
How to prepare
Measure powder with weighing balanced
Pour powder into glass jar
dissolve powder with distilled water or deionised water to reconstitute powder
3.5 if stll in clumps or suspensions, boil the powder to dissolve it
4, Autoclave to sterilise it
1 more item...
If not sterile, filter them by filter steriisation
comes in lyophilised powder that can be stored in refrigerator for weeks
Liquid
broth
pros
easy to prepare and culture large batches of microorganisms
easy to dilute and harvest
Cons
difficult to detect microbial contamination and thus difficult to salvage pure cultures
Semi-solid
1% v/v
sulfide indole motility medium
GAs
You blow air and then boom microorganisms grow LOL
Why do we study microorganisms?
To study the characteristics and behaviour, growth requirements, morphology, genetics
Importance of microbial identification
Epidemiology
To trace and track disease outbreak and the emerging infectious agent
allows communication to stakeholders to prevent spread
Healthcare
Used to identify pathogens to diagnose infectious diseases
Used for therapies
Discovery
To isolate and discover new strains of pathogens
Form new therapies
Biochemical characteristics
To indicate the presence of enzymes which is unique to bacteria
To identify microorganisms that are useful for medical and industrial use
To detect gram-negative, oxidase negative bacteria(enterobactericaea) by using IMVIC, urease and triple sugar iron test
Morphlogy
The response to the stain
shape
Bacillus, oval, coccus
Arrangement
in singly, in pairs(diplo), in chains(strepto), in clusters(staphylo)
Specific structures
absence/presence of endospores
Genetics
To find gene sequence of microbe
Others(blood/serum)
To identfiy which antibody reacts/binds to microbe
Types of biochemical identification kits:
E.coli
E.coli
E.coli 0157:H7
Diarrheagenic
Salmonella
Vibrio cholera
To diagnose infectious disease by identifying pathogens
To detect microbial contamination in environment and food
To make commodity chemicals, pharmaceuticals, food and other useful products
What is microbial growth?
The increase in cell density, cell number and biomass of a microbial population over a given period of time
Why do we study growth?
To study time progress of product formation in relation to cell growth and nutrient utilisation
To know how much bacteria we are working with
To know how much starting inoculum we need
To enumerate the number of bacteria in contaminated food by studying the time progression of toxin production in relation to cell growth
4 Stages
Lag
Cell density-low
Cells are adapting to new growth conditions
beginning to synthesise necessary enzymes for metabolic reactions
Cells have not duplicate yet
Physical space-High
Waste-Very low
Nutrient-high
Log
Cell density
Cells are increasing in exponential rate (cells doubling in every generation)
fastest rate of growth
Nutrient(optimal)
Physical space(optimal)
Waste-beginning to increase
Stationary
cell density=stagnant
Growth rate=death rate
Cells are preparing to face harsh conditions/competition
Waste-high
accumulation of metabolic waste products
formation of cysts, endospores, production secondary metabolic products-antibiotics
Physical space=limited(overcrowding)
Nutrients=limited(decreasing)
Death
live cell density(decreases)
death rate>growth rate
Nutrients(depleted)
Waste
high levels of toxic metabolic wastes
Conditions are overwhelming harsh
Physical space(depleted)-overcrowding
Key factors
Physical space available
Nutrients available
Cell density
Waste
Aesptic techniques
A set of specific practises and procedures performed under carefully controlled conditions to minimise contamination from undesired microorganisms
To protect cultures, equipment and sterilised media from contamination by surrounding
To protect users
Types
Autoclave
Steam sterilisation
To kill endospores and vegetative cells
Steam culture media and equipment under pressure
suitable for thermostable and not suitable for sensitive to moisture substances
Common settings
121oC, 15 psi, 15 mins
115oC, 10 psi, 10 mins
Heat in hot oven
Heat in oven up to 250oC
Suitable for thermostable and sensitive to moisture substances
Helps to kill vegetative cells and endospores
Flame sterilisation
Used for equipment that are used repeatedly over a short period of time
To sterilise inoculating loop, heat it under a bunsen burner until red hot and wait until it cools in the aseptic zone before use
Glass spreader, dip into alcohol and burning off alcohol before use
Filter sterilisation
For media that is not thermostabile
Pass the sample across a membrane and based on size exclusion, microbial cells are too large to pass through the membrane, thus the filtrate is sterile
Isolation methods
Streak plate