E.coli

Hello guys!
Here I go again!

      Today we are going to see a little bit about a very commom bacteria, Escherichia coli, or most known as E.coli. The habitat of this microorganism is humans' intestine and animals. Most of E.coli doesn't  cause disease on their host, however some strain are able to harm. (1)

       The discover of E.coli was in 1885 by Theodor Escherich, when he isolated the bacteria from feces of newborn. Untill 1935, when a strain of E.coli was associated with diarrhea cases in infants, it was seen only as a commensal organism. (2) 

          Some characteristics of this bacteria are listed below:
       - Roden-shaped (bacilli)
       - Gram-negative - looks pink in microscopy image
       - Has LPS (Lipopolysaccharides)
       - Has flagella - permits mobility
       - Facultative anaerobe - grows in presence or absence of oxigen.
       - Belongs to Enterobacteriaceae family
       - In agar plate: colonies are circular, bege, convex.

Take a look at the pictures below, they represent the characteristics above:

Figure 1. In a microscopy magnitude of 1000x  we can see E.coli and three of its characteristics: gram-negative (pink), roden-shape and <1um size. Photographed by SMC Microbiology student Maiary Voltolini, 2014.

Figure 2. In detail, the typical gram-negative cell wall is shown. It has two plasma membrane, external and a intern one. The extarnal had attached many molecules of LPS, as well as other components. Photo from Prescott's Microbiology, McGraw-Hill Science/Engineering/Math; 9 edition (January 8, 2013), p.58.

Figure 3. Growth of E.coli in thioglycollate broth, overnight 35oC. In anoxic condition the bacteria could grow, and also it swam to get nutrients around, so we can notice the facultative anaerobe and flagela characteristic. Photographed by SMC Microbiology student Maiary Voltolini, 2014.

Figure 4. Morphology of E.coli colonies when they grow in agar plate. Circular, bege, convex. Photographed by SMC Microbiology student Maiary Voltolini, 2014.

Figure 4.  MacConkey agar containing two bacteria, one that ferments lactose (in pink) and one that doesn't (yellow) . Image from http://en.wikipedia.org/wiki/MacConkey_agar.

     Bacteria that are able to ferment lactose present in MacConkey agar are seen as pink because they

produce an acid that lowers the pH of media and results in pink coloration.   

For now that is all, next time we will see more about this bacteria. Also, in other posts, Herpes virus will be explored.

       And just for fun, a small cartoon!

Cartoon from Biology Fun Blog. (http://biologyfun.blogspot.com/)

(1) http://www.cdc.gov/ecoli/general/index.html
(2) http://textbookofbacteriology.net/e.coli.html
Prescott's Microbiology, McGraw-Hill Science/Engineering/Math; 9 edition (January 8, 2013)

Starting!

Hello folks!

Well, this is a new blog with a different goal! 

Here I want to let you all guys knowing what I am learning about: microbes!

Actually I will share about two specific microoganisms, Escherichia coli and Herpes virus.

Just to you all know, it comes from an assignment given by Professor Lippert, because I am enrolled in microbiology course at Sain't Michaels College (you've maybe read about in other blog - "A realidade de um sonho").

The puporse of the assignment is to study about two microorganisms, a bacteria and a virus, and share what you are learning. We could choose how to do this, like writing a paper, sharing during the classes, making a presentetion, or... a blog! Particularly I liked this idea very much, because I can post pictures, new stuffs about the theme, and do it in an innovative way.

Two things:

-First, (my Brazilian friends) this blog will be writen in English, the reason I don't need to explain right...

-Second, to native English speakers, I may make some mistakes on writing, as you know I am not at max level of English language yet.. 

But anyway, let's see what happens and how it works! Feel free to make any coments, criticals or suggestions!

I hope you like it!

Figure © 1991 by Gonick & Wheelis, The Cartoon Guide to Genetics.

E. coli K12, the prokaryotic wimp

Escherichia coli is a coliform bacterium that is a normal component of the human intestinal flora, and is ordinarily not a dangerous organism. The K12 and related strains of E. coli used in molecular cloning have been modified so that they are able to survive in culture only under very specific conditions, and unable to survive at all in the human gut. (text © 2009 by Steven M. Carr)