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Julio-Claudian

Member Since 29 Jan 2009
Offline Last Active Jan 27 2013 08:07 PM
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Posts I've Made

In Topic: Spin Column

05 January 2013 - 02:57 AM

Hi,

Ran out of spin columns? :)

http://www.protocol-...s-alternatives/

In Topic: Questions about proper technical approach

05 January 2013 - 02:52 AM

Hi Mindologist,

I'll go straight to your first question. The first thing that came to my mind is to do what's called the genome walking. Bear in mind that I have not done this (or anything similar) before so someone here might have better alternatives.

Here are some stuffs that could be useful:

www.clontech.com/xxclt_ibcGetAttachment.jsp?cItemId=17326

http://www.protocol-...osts/37995.html

www.ucl.ac.uk/~ucbhjow/b200/Cloning_genomic_DNA.doc

http://www.biotechni...ques-44287.html

https://www.ncbi.nlm...cles/PMC306810/

In Topic: Effect of low and high nutrient medium on bacterial attachment?

09 December 2012 - 05:18 AM

These are purely hypothetical:

If attachment is caused by expression of a certain protein that aids/results in the cell attachment (quorum sensing system), and the expression depends on nutrient availability, it then follows that attachment will be affected by the type of medium you use.

Another view is such, that initial attachment is independent of the type of media but after the first colonizers have adjusted to the attachment surface, subsequent excretion of polysaccharide (biofilm formation) could be dependent on media type.

I certainly have lots more to learn from you on this subject :)

http://aem.asm.org/c...71/9/5208.short
http://www.sciencedi...021979708001781
http://onlinelibrary...09.02591.x/full
http://www.sciencedi...168160510000863
http://cid.oxfordjou...33/8/1387.short

In Topic: different orientation or direction of genes in expression Plasmid vector

10 November 2012 - 08:03 PM

The answers to your 'question' Posted Image can be found here http://www.protocol-...s-in-a-plasmid/

In Topic: SEM analysis of Bacteria

19 September 2012 - 06:23 AM

Hi,

It is necessary* to fix the bacteria (or any cells for that matter) prior to viewing on TEM or SEM. As I'm not really familiar with SEM but the steps/principles running up to viewing is quite similar.

According to the protocol from the University of Oxford:

Quote

The main purpose of fixation is:
1) to cross-link cellular structures into a matrix so as to preserve the structure of the cells with the minimum of alteration from the living state (i.e. with no changes in morphology, volume, or spatial relationships, and with minimum loss of cellular constituents) and,
2) to protect and stabilize cellular structures from changes during subsequent treatments and from irradiation by the electron beam.

Fixation is the first and most important step in any EM study, since mistakes made at this point render the whole project useless.

So we see that it's got nothing to do with bacterial/cell attachment to a surface; rather, serving the purpose mentioned above. Only after fixation will the other steps (post-fixation/dehydration/further treatment/drying/coating) be done.
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* Unfixed samples are sometimes used negative staining. With unfixed specimens there is the potential problem of changes occurring due to osmotic shock (or to changes in ionic composition) since most negative stains are made up in distilled water. There are safety implications to be considered when examining unfixed bacterial or viral samples.

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