This question has probably been asked a few times but I get the concept I just dont know how to apply it for this paticular experiment

I aim to use cherry tomatoes and determine its glutamate content after drying for varying amounts of time.
This would involve putting the tomatoes into the centrifuge to extract its juice. Due to this, I am 'preparing' the tomatoes in vivo (I think need clarification) but I am observing the Glutamate content outside of the organism (ex vivo)

I dont know how I should be classifying this experiment (between in vivo and ex vivo)

Help will be greatly appreciated !!! Thank you!!

  • $\begingroup$ This would all be in vitro work. See my comment below the (incorrect) answer. This may also be helpful. $\endgroup$ – MattDMo Jul 12 '16 at 23:58
  • $\begingroup$ Personal opinion: nevermind. Provided it is clear from the your experimental description what you actually did, who cares what to call it in latin ... As the below answers and discussion shows, there is no real consensus on exactly what these old latin terms mean nowadays, and I really think most people just include them in journal articles to appear sophisticated ;-) Just describe your experiments as clearly as possible when writing your paper, so the reader to can judge for him/herself how relevant the data is to the organism you study. $\endgroup$ – Roland Jul 14 '16 at 7:36

The classification usually applies to the experimental conditions. Are the experimental conditions applied to an organism, or to a less than whole organism (cells culture --> all the way to test tube chemistry reactions)?

This is somewhat subjective, but in your case, since the experimental conditions are drying time of the pretty much whole organism (the tomato), I would call it an in-vivo experiment.

Think of it this way, if you treat animals with X and examine Y, this is an in-vivo experiment regardless of whether you are isolating proteins, DNA, RNA etc... to examine afterward to characterize the change in Y.

Now if you isolated cells first from mice and plated them to grow in cell-culture, and then treated with X to examine the same endpoint, this has become more ex-vivo.

In-vitro would be to isolate a single enzyme from mouse cells, put into a test tube, and examine its ability to reduce some substrate after X treatment.

In your case, if you isolated enzymes from tomatoes and then used them in a test-tube to reduce some agent and measure activity before and after a given treatment, this would be more ex-vivo and have gone all the way to in-vitro.

EDITED: Matt pointed out I had confused in-vitro and ex-vivo on my continuum and he was correct.

  • $\begingroup$ This is completely incorrect. You're mistaking ex vivo ("out of life") with in vitro ("in glass", referring to old-fashioned Petri dishes). An in vivo experiment is performed in an experimental organism, such as giving a mouse cancer. Ex vivo refers to taking samples from that organism and processing them separately - surgical or post-mortem removal of the tumor for analysis of the cells and structure. Creating a cell line from the cells and culturing them would be in vitro. $\endgroup$ – MattDMo Jul 12 '16 at 23:50
  • $\begingroup$ @MattDMo In vitro studies are performed with microorganisms, cells or biological molecules outside their normal biological context. In science, ex vivo refers to experimentation or measurements done in or on tissue from an organism in an external environment with minimal alteration of natural conditions. Ex vivo conditions allow experimentation on an organisms cells or tissue under more controlled conditions than is possible in in vivo experiments (in the intact organism), at the expense of altering the "natural" environment. I'll change my test tube example but rest is correct. $\endgroup$ – akaDrHouse Jul 13 '16 at 12:38
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    $\begingroup$ @MattDMo In response to : Ex vivo refers to taking samples from that organism and processing them separately. This is not correct. Ex vivo also means that experimental conditions are applied after taking samples from the animals. No room above, but links to ex vivo and in vivo definitions here: en.wikipedia.org/wiki/Ex_vivo and en.wikipedia.org/wiki/In_vivo The distinction is where the experimental conditions are applied, to the whole organism or to parts isolated from it, not the processing as you stated. $\endgroup$ – akaDrHouse Jul 13 '16 at 12:44
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    $\begingroup$ @MattDMo To add, I routinely process mouse tissue taken from experimental mice in order to determine their protein/RNA expression levels. I would definitely consider these in vivo experiments. $\endgroup$ – March Ho Jul 14 '16 at 0:56

It depends upon your field, and its proximity to native specimen. In practice, in-vivo and ex-vivo are used to stress a relative difference.

  • If you are biochemist in a field / research area that usually uses purified components and reconstitution: in-vivo
  • If you are biochemist in a field / research area that usually measures glutamate within undried tomatoes: ex-vivo
  • If you are a cell biologist: ex-vivo
  • If you are a developmental biologist: ex-vivo

(Similarly cell culture is usually considered in-vivo by a cell biologist, but ex-vivo by a developmental biologist).


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