Day 2: 5/15

Followup on the Unknown Bacteria "N"

Today we pulled the four samples of "N" bacteria from the incubator and inspected the growth that occurred. Viewing each specimen under a compound microscope we made the following observations:

The plate had a lot of bacteria and in lab we classified the type of colony.  The isolated colonies had circular growth, the pigmentation was a colorless white.  The colony surface was opaque, transparent, smooth, glistening with a glue-like appearance. The colony margin was entire due to the smoothness of the edges Finally the elevation of the isolated colonies were convex.

For the slant culture the medium was slightly liquid and our speculation was a root-like like Rhizoid.

The Broth culture had some growth, although not quite turbid. However the particles were flocculent meaning scattered about the liquid.

Viewing Live Microorganisms in the Unknown Bacteria

The goal of this experiment is to see the size shape and arrangement of the live microbes. Also to observe to observe live bacteria that use flagella for motility.



Materials:
slide with depression
square cover slip
petroleum jelly
toothpick
inoculating tube
Bunsen burner
"N" bacteria in broth



In this experiment using the Aseptic technique with a inoculating loop we transferred the "N" bacteria broth to a depression slide.  Placing one drop in the center on the depression. Placing dabs of petroleum jelly with a toothpick on all four corners of the square cover slip we carefully covering the slide with the cover slip.
After observing the live microorganism under the microscope we discovered a great range of motility.  The bacteria we very small in size and moved in an upward motion.

Simple Staining of the Unknown Bacteria

The purpose of this experiment is to stain the bacteria to see it more clearly and further classify shape, size and arrangement in a fixed smear.

Fixing the Smear:
We used a different method of placing the unknown bacteria on the slide called a fixed smear.

Materials:
plate of unknown bacteria
broth of bacteria
slide
Bunsen burner
forceps

Using Aseptic technique we transferred the pure colony bacteria and broth culture bacteria to a microscope slide. After letting it completely air dry we used the forceps to hold the slide and passed it over the Bunsen burner three times.

Simple Staining of the Bacteria Smear:

Materials:
slide with fixed smear
bottle of stain with dropper
staining rack
Distilled water
bibulous paper

This process involves staining the bacteria smear to see more clearly under a microscope.  To start the process we placed the dried bacteria smear on the staining rack that is resting over the sink.  After dropping three drops of methylene blue stain on the smear we waited two minutes and then rinsed off the excess stain with distilled water.

 Then we blotted the now stained bacteria smear with bibulous water to get rid of excess water.  Finally we examined the stained smear under the microscope using oil immersion lens.  Our unknown bacteria was very small and rod shaped.

Also in lab today we were show the effect that blue and red light has on the effect of resolution.  We learned in lecture yesterday that shorter wavelengths of light have more energy and are more powerful.  So the difference between the red and blue slide show that using a blue screen allows greater resolution.