Biofilm generation methods Flashcards
describe a technique used to screen deletion mutants for their ability to form biofilms in different media
culture mutants in 96 well plate
treat with different media
stain with Safranin
extract absorbed stain and quantify on spectrophotometer
microtiter plate assay for biofilm formation
what are the disadvantages to high throughput sequencing for antimicrobials or mutatnts in a 96 well plate?
a binary system - they either have a reaction or not, omits a lot of information, could lead to misjudgments
cant tell whether it is a biofilm or sedimented single cells
what method did howard cherry develop to overcome the issues with growing biofilms in wells
MBEC™ high-throughput (HTP) assay (anti-gravity)
he created a system that used pegs that dip into the fluid of the wells in the 96 well plate to form a biofilm despite gravity
what are the pros and cons of lab flow cells?
- Not robust, low shear, slow flow
- Linear gradient effects?
- OK for direct microscopy but need to be transparent
how are removable flow cells better than lab flow cells
* Robust, higher shear
an adapted version – have clamps where you can clamp materials to the side on the openings this allows for higher shear
describe ATR-FRIR Ge crystal flow cell
Attenuated total reflectance fourier transform infrared spectroscopy
Have flwo cells, flow media in one end comes out the other. Below you have a crystal that you shine light through. Within the cell you have biofilm attaching to crystal. Light bounces inside the crystal. Evanescence wave you get radiation leaking out into biofilm before it returns back with the main wave. Different crystals have a different evanescent wave. You take the light and analyses the evanescence wave, you get a spectrum and see chemical bonds. From these spectra you can get the chemical profile of the biofilm without disturbing it.
why was the robbins device developed?
brefily describe it.
In Canada (one of worlds largest oil producers) they have a lot of pipe work. Problems with souring form hydrogen sulphide from biofilms in pipe
Engineers had to come up with robust pipe work for high pressure oil systems.
Pipe had studs tightly screwed in with coupon at bottom.
Robust, high pressure
access different materials
how is the modified robbins device different from the original robbins device
lab model - smaller, simpler plugs
not robust (frequently leaks), low pressure
shear effects at start and linear gradient
breifly describe the hedgehog device
big pipe with flanges, studs all the way around
what are sentinal coupons?
give an advantage
serpentine device,with curved coupons
more hydrodynamically homogenous so fewer artefacts compared to flat coupons
what are annular reactor models suitable for?
- biofilm structure and function
- pathogen survival
- biocide efficiency
- material biofouling
what are the advantages to annular reactors?
- flow through design with tap water as feed
- ability to change influent water quality by adding different feed solutions
- capability to control shear stress by changing the rotational speed of the inner drum
- ability to control hydraulic retention time through influent flow rate
- hence, shear stress and hydraulic detention time can be set independently
- biofilm sampling by removal of coupons from reactor
what are annular reactors?
a fermenter system with an inner and outer drum
the two have a gap between that can be controlleld
one is rotated to define the shear force
long coupons
developed in boseman montana
what are the disadvantages to annular reactors?
eddy current effects
x and y gradients
give some details about the annular reactor procedure
flow rate, media exchange, rotation speed, flow velocity, shear force
- flow: 4 mL/min
- exchange of the media: 9.3 x per day
- rotation of inner cylinder: 200 rpm
- flow velocity: 0.45 m/s
- shear force: 2226 Re
