Help Identifying Large Hay Infusion Bacilli

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desertrat
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Joined: Thu Apr 05, 2018 1:06 am
Location: Idaho

Help Identifying Large Hay Infusion Bacilli

#1 Post by desertrat » Wed Nov 21, 2018 3:14 am

A couple of years ago I made some hay infusions and made slides of the bacteria growing at the surface over a period of time. I posted some images a while back of slides made during early stages of growth of the cultures.

Later on I noticed the surface film was thicker and less transparent looking. A couple of permanent stained slides were made and I discovered almost all the previously seen bacteria were gone and replaced by very large bacilli growing close together in a matrix. The shape of these can be made out with a 10x objective.

I looked around on the 'net for identification keys, but it doesn't seem to work that way with bacteria. Since there are only a few general shapes, they are identified by size, shape, growth medium, staining properties, etc.

I was wondering if someone here with experience with bacteria might recognize these unusually large bacilli.

The slides were made by transferring a small piece of the surface film more or less intact to a coverslip. After drying at room temperature, the films were fixed by pipetting on a few drops of 98% denatured alcohol. This particular brand is about a 50/50 mix of ethanol and methanol. Bacterial films are often fixed by passing through a flame, but that takes some practice and too long in the flame can incinerate the specimens. The alcohol method I read about in a late 19th century manual on bacteriology, and seems to work well in this case.

After the alcohol evaporated from the coverslip, a 1% aqueous solution of methyl violet stain was pipetted on the films. The methyl violet is not a certified stain, but some technical or lab grade with no suffix, maybe used for an indicator. It seems to work well on the bacteria that it's been tried with so far.

After a few minutes, the stain was replaced with distilled water pipetted on the coverslips. The coverslips might have then been placed in a small bowl of distilled water for a short while, but I don't remember exactly and wasn't taking notes. After the coverslips were dry, they were turned over so the stained films were on the undersides, and then carefully lowered onto a drop of canada balsam on a slide.

The slides were set aside for several days for the slowly drying balsam to set up enough so they could be examined under the microscope.

Below is a portion of the field of a film of these large bacilli, viewed with an antique Spencer Lens Co. 95X fluorite objective, mounted on a A/O Spencer 4 Series stand.
Large_bacilli4.JPG
Large_bacilli4.JPG (206.02 KiB) Viewed 2834 times
Below is a portion of the edge of the film with some normal sized bacilli. A little image sharpening was done in GIMP.
Large_bacilli2a.JPG
Large_bacilli2a.JPG (232.29 KiB) Viewed 2834 times
Anyone have any information on these large hay infusion bacilli?
Rick

A/O 10 Series Microstar
A/O 4 Series Microstar
A/O 4 Series Phasestar
A/O 4 Series Apostar
A/O Cycloptic Stereo
Several old monocular scopes in more or less decrepit but usable condition

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