Bacterial lawn is a term used by microbiologists to
describe the appearance of bacterial colonies when all the individual colonies on a Petri dish
agar plate merge to form a field or mat of bacteria. Bacterial lawns find use in screens for antibiotic resistance and bacteriophage titering.
What is the difference between lawn and colony bacterial growth?
Colony Vs Lawn
Most bacteria grow in colony format and colonies will only appear on areas of the plate that were streak on and it look like small white circle on petri dish. But for swarming (lawn) growth, it will look like
a hazy blanket of growth
that extend beyond the area you made the streaking.
What causes lawn bacterial growth?
Wet portions on your plates due to condensation
can often cause lawns to form due to an excess amount of liquid on your plates combining with your transformation sample. This also depends on how effectively you’re spreading your samples.
What is a bacterial colony?
A bacterial colony is
what you call a group of bacteria derived from the same mother cell
. This means that a single mother cell reproduces to make a group of genetically identical cells, and this group of cells form a mass, which is known as a bacterial colony.
What does bacterial growth look like?
The margin growth of a bacteria describes how the edges of the colony appear under a microscope and can appear: with a
smooth rounded edge
called entire. Bacteria can grow with a bumpy edge called undulate. A filiform margin has small branch like growth that spreads outward.
How does lawn growth occur?
Lawn growth is
where the surface of the plate looks like a lawn, covered all over and with bacterial colonies merging with each other
. Why does use of Lux plasmid lead to bioluminescence?
Why do we get colonies of bacteria on this plate and not a lawn of bacteria?
Empirical differences: you may get a lawn of bacteria on a plate as opposed to defined punctate colonies
because too much bacteria were plated
. This is why researchers plate serial dilutions on bacteria plates if they are inoculating plates from a culture of unknown concentration.
What does a bacterial lawn indicate?
Bacterial lawn is a term used by microbiologists to describe
the appearance of bacterial colonies when all the individual colonies on a Petri dish agar plate merge to form a field or mat of bacteria
. Bacterial lawns find use in screens for antibiotic resistance and bacteriophage titering.
Which antibiotic was most effective in killing the bacterial lawn?
“Post-Lab Questions”
Which antibiotic was most effective in killing the bacterial lawn? Which was the least effective?” The most effective was
Kanamycin
. The least effective was Penicillin.
How do you tell the difference between a bacterial colony and a fungal colony?
The main difference between bacterial and fungal colonies is that
bacterial colonies are small, smooth or rough colonies with defined margins while fungal colonies are large colonies with a fuzzy appearance
. Furthermore, bacterial colonies look wet and shiny while fungal colonies are powder-like.
What are the different types of bacterial colonies?
The Figure below shows four of the common and characteristic shapes of bacteria:
cocci (spherical), rods, vibrio (comma shaped) and spiral
. Cocci. The organism shown (top left) is Micrococcus luteus, which forms tetrads due to regular alternation of the plane of cell division.
What are the two types of bacteria?
There are broadly speaking two different types of cell wall in bacteria, that classify bacteria into
Gram-positive bacteria and Gram-negative bacteria
.
How do you choose bacterial colonies?
A suitable colony grown on an agar plate is isolated for picking. The colony is isolated with a colony-picking tool such as
a toothpick
, inoculation loop, or pipette tip. It is then inoculated in a solid or liquid cell culture medium where it is incubated overnight to encourage replication.
What are 3 methods used to identify bacteria?
Traits that can be valuable aids to identification are combinations of cell shape and size,
gram stain reaction, acid-fast reaction, and special structures including endospores, granules, and capsules
.
What are the 4 stages of bacterial growth?
Bacterial colonies progress through four phases of growth:
the lag phase, the log phase, the stationary phase, and the death phase
. The generation time, which varies among bacteria, is controlled by many environmental conditions and by the nature of the bacterial species.
What are the 7 types of bacteria?
Bacteria are classified into five groups according to their basic shapes:
spherical (cocci), rod (bacilli), spiral (spirilla), comma (vibrios) or corkscrew (spirochaetes)
. They can exist as single cells, in pairs, chains or clusters. Bacteria are found in every habitat on Earth: soil, rock, oceans and even arctic snow.
