Posts that relate to the Keyword: bacteria

How does alcohol chemically fix specimens?

Alcohol can be used for fixing specimens, but is not commonly used for fixing bacteria.

Setting up a Home Laboratory for Microscopy

Why a home lab? For someone who wants to observe ready-made permanent slides or an occasional pond water sample, a fully equipped home laboratory may not be necessary and somewhat of an overkill. In this case it is sufficient to find a reasonably dust-free place to store and operate the microscope. The microscope can then [...]

Life in the Flower Pot Water (or: Comparing the Size of Prokaryotes and Eukaryotes)

Over the past few years, I’ve met several students who wanted to see bacteria through the microscopes that we have at school. Unfortunately, these devices are not equipped with phase contrast optics. The transparent bacteria are therefore difficult (but not impossible) to see. The biggest draw-back, however, comes from a different source: some of the [...]

Fixing specimens for making permanent slides

Before specimens can be processed for making permanent slides, they may need to be fixed. This step kills the specimen and preserves the structures. It also prepares the specimen for staining. There is no one single method to fix a specimen, too much depends on the nature of the specimen itself and on the subsequent [...]

Q & A: What people searched for

In this post I’d like to address some of the search queries that people typed to find this web site. Naturally people typed many, many more search queries, most of the queries are made of 1 or 2 words. I selected the longer ones for this post. Q: What is the principal advantage of an [...]

Bacteria in phase contrast

About phase contrast Bacteria are transparent and therefore difficult to see using regular bright-field microscopy. The bacterial cells will appear just as bright as the surounding medium and there is no color contrast. Phase contrast optics provides a solution. Phase contrast optics convert the differences in optical density (i.e. the refractive index) of the bacterial [...]

Observing bacteria under the light microscope

It is possible to use non-toxic stains (such as ink for fountain pens) to stain yogurt bacteria in-vivo.

Staining bacteria

Here is yet another link to an article from Popular Science magazine. It deals with the isolation, fixing and staining of bacteria. I would not recommend the use of some of the solvents that they use (such as xylol) with children, however. They also describe a blood smear preparation, what I do not recommend for [...]