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What can we see on this photomicrograph? - (Aug/23/2013 )

i cultured some cocci on an agar plate and stored this plate for approximately one week at 4°C. Then, i examined the cells using a light microscope. Where I applied the cells to the object slide, I could observe the following image at 40x magnification.

I don't think that these are cells but debris. But what exactly does this debris consist of? How does it emerge and how to avoid it? Why the debris is at a different layer than my cells (heat fixation)?

In terms of debris reduction, would it be better to culture the bactoeria in liquid medium or not storing the agar plate at 4°C.

Thanks for you responses.


To observe the cells properly you need to use a 100x objective.  From this picture you can't say much.


40x objective or total magnification?


Really hard to say anything

-El Crazy Xabi-

40x objective, 400x total magnification.



I did Gram stain again. One more time, at 400x, I could see the above mentioned image.

With 100x magnification I have these photos. The first row is from one isolate. The second row from another isolate. I think it is Gram positive Corynebacteria. Do you agree with this?


I wonder that the cells on the right image of the first isolates looks a little bits coccoid.

For isolate 1, there are big round spots (maybe part of the club-shaped Corynebacterium?) The space between the spots sometimes isn't stained properly.

This doen not apply to isolate 2.



Also, I have a very basic question to which I could not find any answer in papers or university lectures.

WHAT exactly does Safranin stain? I just found a reference that it stains the nucleus but for bacteria??


You mean in the Gram staining? Safranin is just a contrast/counterstaining added to stain those cells that wouldn't stain otherwise by the first step. In fact, the safranin didn't appear in Gram's original protocol

-El Crazy Xabi-

The image is from Gram staining :)
yes that's what I read but do you know to which structures of the cell safranin binds?
What do you think about the genus of my bacteria?


Cells appear to be coryneform.

-Phil Geis-