Dispersion staining objectives

[Rossf]

Been reading a bit about these-just curious in the spirit of using techniques in applications that wasn’t intended for can these objectives do anything interesting in observing microbes? Apart from showing your paramecium has asbestosis?
Regards ross

[Wes]

Not that most of us can't use Google but a link would be useful if you want to engage in a productive discussion.

[microcosmos]

I think it could be used to measure the refractive index of the protoplasm of microbes, with water as the reference medium, although I haven't come across any actual use for this purpose.

Perhaps the refractive index could be an indicator of the physiological state of the cell? Change in refractive index could be a more sensitive measure of subtle changes in cellular metabolism than the visual appearance of the cell.

Could one do experiments by modifying the environment conditions (e.g. salinity, water stress) under the coverslip or in a petri dish and measure changes in the refractive index using dispersion staining?

Has any research been done in this area?

[Rossf]

Thanks for replying-I’ve tried to find articles but they all seem to be behind paywalls-not that I’m against paywalls necessarily but budget not in shape-I’m just always curious about non standard uses of specialised objectives-from what I did read there are different types of dispersion objectives some using a dark stop inside the objective and others different designs. Will keep trying to find more info.
Regards ross

[microcosmos]

No problem. Actually, your post made me go read up about it and learn something myself! I previously assumed that I couldn't do dispersion staining without the dispersion staining objective, but now I realise I can actually do it with a regular objective!

Here's one article (no paywall) that I feel explains all the different types of dispersion staining quite clearly, if you haven't seen it already: http://earthresources.sakura.ne.jp/er/EV_EI_A(2)_06.html

I'm not a fan of paywalls either, although I understand that they're just as legitimate as other ways of making money. The great thing is that there's more than enough free and open information on the internet that people like us who don't allocate budget for paywalls can still benefit from the collective wealth of human knowledge.

[Scarodactyl]

they're just as legitimate as other ways of making money.

I wouldn't say so. The publishers insert themselves as parasitic middle men into the scientific process. Researchers do all the labor to create the articles (along with all the formatting in some cases! On my one proper paper the only suggestion I got from the journal copyeditor was to change the technical term 'grus' to 'grubs') In fact, the researcher often pays for the privilige of being published--there were over 1k in fees for my paper in American Mineralogist, which the department fortunately covered. Then other researchers do peer review work for free to vet the paper, and finally institutions pay for access to these papers. The journal's main contribution is to take all of the money for themselves.

[microcosmos]

I agree with you in the case of many scientific journals. But I was thinking of paywalls in a broader sense, including paywalls for newspapers (such as the New York Times and Financial Times) which I think are actually doing something positive in keeping good journalism afloat today. So I think paywalls per se are legitimate, but as you gave an example, some may be abusing the system.