L3: Direct examination of microorganisms

aliquots of the specimen

what are used to prepare wet mounts and smears

wet mount

one of the mot basic preparations for microbial microscopy

wet mount

this procedure is used to demonstrate the bacteria’s size, shape, and motility without the use of any stain

size, shape, motility

what characteristics of a bacteria is demonstrated in wet mount preparation (SSM)

hanging drop method

variation of wet mount where the sample is suspended on a depression slide

hanging drop method

the technique used to prevent the early evaporation of smears

evaporation of smears

common disadvantage of wet mount

Brownian motion

refers to the random movement of particles as they collide with one another

True Bacterial Motility

movement of bacteria that is directional and may be seen in specific pattern

Bacillus subtilis

specimen used in hanging drop method

• Procedure

• Date/Time performed

• Initials of the student

information needed in labeling the slide

18-24 hours

required culture time of B. subtilis for wet mount

because it has different refraction index in which OIO isn’t compatible with

why isn’t OIO used for hanging drop method

1 drop

how many drop of the bacterial specimen should we use for wet mount preparation

petroleum jelly

what holds the cover slip to the slide and also keeps the suspension from drying out

not colored

disadvantage of wet mount

wet mount

specimen preparation that involves direct placing of coverslip before viewing under the microscope

HPO

up until what objective do we only use for hanging drop method

swarming motility

what is the motility of Bacillus subtilis

• this is due to their flagella

wet mount & hanging drop method

2 examples of direct examination of organisms