I check my web server’s logs fairly regularly. Given that right now this is a brand spankin’ new blog with a pitifully small readership (Hi, mom!), seeing a new reader (even just a casual drive-by reader) is interesting to me.<\/p>\n
I just noticed someone bounced by the site, having gotten here via a Yahoo search for the question above. Just in case they come back (or anyone else comes by and is interested, for that matter), here’s the answer – at least to the best of my knowledge.<\/p>\n
Have you ever thrown a piece of meat into a hot pan or barbeque that wasn’t sufficiently greased? You notice how it sticks and doesn’t want to come off? That’s what heat-fixing is for. It basically “bakes” the bacteria to the surface of the slide, so that when you then soak the slide with stains and rinse it with water and\/or alcohol and\/or other substances (like the “acid alcohol” stuff used for the “acid-fast” stain for Mycobacteria<\/span>) they don’t get washed off. This can be an issue, since some of the staining techniques have a whole series of “soak\/rinse\/soak\/rinse\/soak\/rinse” kind of steps with different kinds of solvents, and it would be very annoying to go through all that work and find out you’ve rinsed the stuff you wanted to look at down the sink in the process. It’s also nice if you want to look at the slide with an oil-immersion lens<\/span>.<\/p>\n You can’t really “glue” the bacteria to the slide with some sort of chemical, either, since anything you “glue” them with might cover them and interfere with stains that you’re trying to soak them with so you can see them in the microscope.<\/p>\n Actually, it’s probably worth mentioning that since most sources seem to unfortunately assume that “microbiology” just means the tiny fraction of a percent of microbes that cause diseases, a lot of sites will also say that the heat-fixing process is also “to kill the bacteria” (so that if you are overcome by an uncontrollable urge to lick the slide<\/span> later or rub it on an open wound for good luck or something, you hopefully still won’t get the disease). While it’s true that heat-fixing ought to kill just about any microbe on your slide, I suspect that most of us who are looking at things that aren’t<\/em> disease-related probably don’t consider this a “purpose” of the heat-fixing process. Still, if you’re answering a question like this on a “General (medical-centric) Microbiology”-type exam, you may want to mention this as well. Hopefully that information will be of interest or use to someone…<\/p>\n Coming up next – some commentary on the history of staining bacteria, and why it seems like all of the classic techniques of microbiology – most of which seem to still be in common use – seem to have been invented entirely in or near Victorian-era<\/span> Germany…<\/p>\n Also possibly coming soon: Discussion of the “Everything is Everywhere” concept, making chemicals with bacteria, and (if I can manage to get the thought into some organized form) a simple discussion of the concept of speciation<\/span>, using science itself as an example. And various other things as I think of them and get time to type them up.<\/p>\n","protected":false},"excerpt":{"rendered":" I check my web server’s logs fairly regularly. Given that right now this is a brand spankin’ new blog with a pitifully small readership (Hi, mom!), seeing a new reader (even just a casual drive-by reader) is interesting to me. I just noticed someone bounced by the site, having gotten here via a Yahoo search … Continue reading “What’s the purpose of heat-fixing bacteria on a slide?”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6,8],"tags":[],"class_list":["post-17","post","type-post","status-publish","format-standard","hentry","category-microbiology","category-why-does-it-work"],"_links":{"self":[{"href":"http:\/\/www.bigroom.org\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/17","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.bigroom.org\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.bigroom.org\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.bigroom.org\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.bigroom.org\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=17"}],"version-history":[{"count":3,"href":"http:\/\/www.bigroom.org\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/17\/revisions"}],"predecessor-version":[{"id":556,"href":"http:\/\/www.bigroom.org\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/17\/revisions\/556"}],"wp:attachment":[{"href":"http:\/\/www.bigroom.org\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=17"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.bigroom.org\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=17"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.bigroom.org\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=17"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\n(UPDATE 2010-08-25<\/b> I dug up some Real Science™ on this “killing the bacteria” idea in “Stir-Fried Stochasticity Episode 4: TuberculosisBurgers<\/a>“, which is an amateur podcasting project I’m dabbling in. I’d very much appreciate feedback on it!)<\/p>\n