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Passaging cells


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12 replies to this topic

#1 msc2012

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Posted 31 July 2012 - 02:25 AM

Hi all!

I'm currently in debate with another member of my lab.

We've all been told that passaging cell lines too many times is not good for them and should be limited, but what does this mean?

1. Does this apply only to adherent cells? My colleague believes it cannot apply to suspension cells because all you are doing is transferring the cells to another flask with some more medium, which is hardly going to have any detrimental effect on them

2. On an equally important note, how exactly does one pronounce passage. Is it like massage or like sausage? There is someone else in my lab who says it is a silent p and should be pronounced assage.

Many thanks for your help!

MSC

#2 doles

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Posted 31 July 2012 - 03:06 AM

Hi,

Too many passages can result in the genetic and phenotypic changes of cell lines. (I saw formerly a work report where two cultures of the same cell line had different passage numbers, and the culture with higher passage number lost the described characteristics (phenotype) of the cell line, but the culture with the lower passage number retained them.)

Marton

Edited by doles, 31 July 2012 - 03:44 AM.


#3 msc2012

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Posted 31 July 2012 - 03:58 AM

Hi Marton, thanks for the reply

But did this report you mention apply to adherent cells or suspension cells? And how do you pronounce the word passage?

Thanks!

#4 doles

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Posted 31 July 2012 - 04:42 AM

It was an adherent cell line (perhaps Caco-2). Potential genetic changes apply to both adherent and suspension cells.

The distinction between the treatment of adherent and suspension cultures probably derives from another general rule: The adherent cell lines must not culture for long time in confluent form, because they can lose their contact inhibition (Adherent cells usually stop dividing when cells reach the confluent state.) Obviously, this rule concerns only adherent cells.

I am not a native speaker, but I think it should be pronounced with 'p'. (Dictionaries usually contain the pronunciations.)

Marton

Edited by doles, 31 July 2012 - 04:50 AM.


#5 leelee

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Posted 31 July 2012 - 06:10 AM

Silent "p"? Wonder where they got that from? That's a new one! Posted Image

You most definitely pronounce the "p". And, in my opinion, the correct pronunciation is the same as massage, although you will find much conjecture about this- and it really doesn't matter, people will know what you mean.
(I've honestly never heard anyone pronounce it the other way though)

To passage your cells is to sub-culture or "split" them, and yes it applies to suspension cells too. Your colleague was wrong to say it doesn't. Each time you take some of your suspension cells and sub culture them into fresh media, this is a passage.

With suspension cells, you would let them grow until just before they reach maximum density (when they are still in the range that is optimal for growth), and you would sub them into new media- this would be a passage. Of course this will have an effect on the cells, growing and dividing continuously is going to have some effect on cells no matter how you are growing them.

#6 msc2012

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Posted 31 July 2012 - 06:42 AM

Thanks Leelee!

Not sure where my colleague got the silent p from, but she is adamant she is correct and is continuing to pronounce it as "assage". Hopefully others can confirm that you are right.

Your comments were very useful, much appreciated.

#7 YMCA

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Posted 31 July 2012 - 07:24 AM

Hi msc2012,

Good to hear from you. My European colleague is very interested in cell passage. He is also a book reviewer but that's irrelevant. He told me that cell passage is pronounced 'assage' with a silent p so I beg to differ with leelee.

Either way I wish you all the best with your cell splitting- it sounds like you are giving it a lot of thought and that's the main thing!

Best wishes from the Middle East

YMCA

#8 doles

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Posted 31 July 2012 - 07:43 AM

Your European colleague may be French, they like omitting the letters. Posted Image (For instance, they do not pronounce the first h and last e of a word. )

Edited by doles, 31 July 2012 - 07:43 AM.


#9 beatrix kiddo

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Posted 31 July 2012 - 07:51 AM

Agree with doles. French people have a habit of omitting words. Try and learn pronounciation from an english person YMCA

#10 msc2012

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Posted 31 July 2012 - 08:03 AM

Thanks for all the comments, much appreciated. i feel that going with the p is the way to go, but YMCA's European colleague and my the girl in my lab have certainly provided an alternative point of view that must be considered.

By the way YMCA, it's interesting that your colleague is a book reviewer, since my lab colleague is considering writing a book on cell culture. She was initially interested in primary cells, but has now spent a significant amount of time studying all permutations related to the growth cycle of cell lines (in particular K562). She really is very passionate about cell proliferation kinetics, although has yet to find an exact definition of what this means.

Thanks again everyone! Any more thoughts on pronunciation will be gratefully received!

#11 pito

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Posted 31 July 2012 - 12:49 PM

It was an adherent cell line (perhaps Caco-2). Potential genetic changes apply to both adherent and suspension cells.

The distinction between the treatment of adherent and suspension cultures probably derives from another general rule: The adherent cell lines must not culture for long time in confluent form, because they can lose their contact inhibition (Adherent cells usually stop dividing when cells reach the confluent state.) Obviously, this rule concerns only adherent cells.

I am not a native speaker, but I think it should be pronounced with 'p'. (Dictionaries usually contain the pronunciations.)

Marton


Hi msc2012,

Good to hear from you. My European colleague is very interested in cell passage. He is also a book reviewer but that's irrelevant. He told me that cell passage is pronounced 'assage' with a silent p so I beg to differ with leelee.

Either way I wish you all the best with your cell splitting- it sounds like you are giving it a lot of thought and that's the main thing!

Best wishes from the Middle East

YMCA

Thanks Leelee!

Not sure where my colleague got the silent p from, but she is adamant she is correct and is continuing to pronounce it as "assage". Hopefully others can confirm that you are right.

Your comments were very useful, much appreciated.

Your European colleague may be French, they like omitting the letters. (For instance, they do not pronounce the first h and last e of a word. )



Not sure where you people got this idea...

But there is only 1 way to pronounce it... its with a p...

There is no silent P in french..

The H is silent at the start of a word, but thats because in 99% of the cases the H has "no point" in pronouncing...

try to hear the difference between "hotel" and "otel" or "hospital" vs "ospital" or "him" vs "im" (pronounced in english)... the letter H is really soft and a "nuance" .. so in french its not pronounced.
(unless you are of course pronouncing it very stronly... but nobody does that.. it would sound a bit weird..)


And about the last "e" not being pronounced: not right.. they do pronounce it.. I am guessing you just assumed they dont pronounce it because mny words have 2 "e"s at the end or a è or é , which makes it harder to know if there is an e or not.
For example: "belle" is pronounced with a very soft "e" , while "eté" has a strong "e" , so for people not knowing french it looks like only the "é" is pronounced and not the "e".
(this is what is writting in many dictionaries about it: An unaccented E at the end of a word is called an e muet and may or may not be pronounced)

Anyway msc 2102 and YMCA, tell your "french experts" to listen to this: http://www.forvo.com/word/passage/
putain alors, assage.. quel consPosted Image


PS. the "p" is often silent at the end of words... if you have doubts about silent or not: the first letter is most often not silent.. the last one: yeah, its often silent..

If you don't know it, then ask it! Better to ask and look foolish to some than not ask and stay stupid.


#12 doles

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Posted 31 July 2012 - 10:58 PM

Hi pito,

I was kidding, excuse me. I have tried to imply that European people often are not native English speakers, and their pronunciation sometimes are not correct. (Of course, omitting h and e letters concern only French language.)

Marton

#13 pito

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Posted 01 August 2012 - 12:09 PM

Hi pito,

I was kidding, excuse me. I have tried to imply that European people often are not native English speakers, and their pronunciation sometimes are not correct. (Of course, omitting h and e letters concern only French language.)

Marton


Well, it all depends on what countries you compare, for example: french people speaking english => disaster... Same for a lot of spanish people.
People from belgium, thats better..

But you are right: french people speaking english often gives weird results, so it could be that his collegue is indeed french altough, it doesnt really make sense since the word is pronounced with a p in french too and its +- the same pronounciation in french or english for the word passage. Only the end part is a bit different.. in french its more passaaaaaaage

If you don't know it, then ask it! Better to ask and look foolish to some than not ask and stay stupid.





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