humans die of a couple different main factors such as suffocation, blood loss, heart failure, starvation, dehydration, etc., etc., etc.; but what kills germs? different solutions such as hydrogen peroxide supposedly kill them, but how?
Wow, big question. Germs can die in lots of ways. In fact in as many ways as people. They are single celled critters, so the death involves only one cell at a time, but the only difference between this and human death is that human death involves lots of cells dying at once. The basic mechanisms of cell death are the same.
Poisons kill them in a huge number of ways. Some foul up the electron transport pathways and basically stop them burning food for energy. Some stop them from reproducing in various ways. Some choke up the pores on their surface and stop them taking in food, and so starve them to death. Some disrupt the surface pores and cause too much water, salt, food or whatever o pour through, causing them to explode or choking them up.
Hydrogen peroxide can work in a number of ways. Most commonly the peroxide flows straight into the cell, simply because it is a small molecule and nothing is keeping it out. Peroxide is a very powerful oxidant. Inside the cell it starts oxidising the various cell components, including the fats and proteins. This oxidation denatures them, rendering them useless. Since pretty much every thing happening in the cell depends on these substances the cell shuts down and can’t restart. It’s equivalent to cooking the cell. Most germs have mechanisms to cope with peroxide (it’s a substance they produce naturally themselves) but thy can’t deal with massive quantities.
Peroxide also causes mutations, which can kill germs, but this isn’t the principle mode of action.
Or, you can use alcohol to screw up the osmotic pressure, and blow the bastards up. Well, OK, they’d actually dessicate, but “dessicate the bastards up” doesn’t sound as tough.
Now let me ask you what you mean by germs, Gypsymoth3 and Blake. Are you referring to bacteria, viruses or disease-causing single-celled organisms such as amoebae? I’m already assuming that by germs you mean tiny little lifeforms which cause disease, but I love microbiology way too much to let a failure to differentiate on what kind of germs you’re asking about just go without comment. 
First things first, there are two basic kinds of cells: prokaryotic and eukaryotic. The main difference between them is that prokaryotes don’t have a true nucleus and they also lack many of the organelles which eukaryotic cells possess. A bacterium is an example of a prokaryote. An amoeba is a eukaryote. On top of that, the overwhelming majority of bacteria have cell walls in addition to cell membranes, while the only eukaryotes which have cell walls are plant cells (and amoebae aren’t considered plants). So if, for instance, you have bacillary dysentery and your best friend has amoebic dysentery, your respective treatments (i.e. killing these different germs) will be different.
Now a virus is completely different. It is not a cell at all. Very basically, a virus consists of a “package” of genetic material (can be DNA or RNA) “wrapped” in a protein coat.
Now if you wanna know how to kill these poor little buggies, tell me what kind you really mean.
Infectionately…
Gee, with a name like Yersinia you have an intersts in micro. Colour me surprised.
By germs I mean any unicellular (or potentially unicellular) lifeform capable of causing disease. That covers bacteria, archae, fungi, protists and the micellaneous odd things. My comments apply equally to all of them. As I said, actually listing every posible way of killing a germ would be as time consuming as listing every way to kill any other organism.
Viruses were deliberately excluded because the OP asked how to kill 'em, and as far as I’m concerned viruses aren’t alive to begin with. You can denature a virus, but you can’t kill it.
It would seem that Blake joined the SDMB back in Mar 2001 and has been biding his time, just waiting for this OP.
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[sup]Very interesting[/sup][/ul]
I’m an ex-microbiologist with a really twisted and warped sense of humor (can you guess which germ I named myself after?). For reasons of conscience I won’t work in the field anymore, but that doesn’t mean I don’t still think micro is cool. But, moving right along…
Of this list of organisms, the only pathogens (to humans, that I know of) are bacteria and fungi. However, you’re quite correct by saying that listing all means of killing even just bacteria and fungi would be rather time consuming – at least if you go into a lot of detail about how each killing method works. I might possibly consider a “basic post” on some of this.
Actually in the scientific community there’s a debate as to whether they’re considered life forms or not. Personally, I take the side that they ARE alive, and here’s why:
(1) They contain GENETIC MATERIAL which they use for replication (their form of reproduction). All life has genetic material and reproduces (hmm, maybe I’M not alive; I don’t have or want kids, hee hee). The only difference between viruses and other life forms here is that while virus genetic material can be either DNA or RNA (this is why I think viruses are cool, too!). All human, animal, plant, bacterial, fungal and other microscopic life uses DNA only as its genetic template.
(2) To those who argue that viruses aren’t alive because they cannot replicate without their host cells, I have to issue the reminder of organisms known as obligate parasites. An obligate parasite is a living organism which lives inside the cells of its host. Well known examples include the bacterial genera Rickettsia (ever hear of Rocky Mt. Spotted Fever?) and Chlamydia (yup, some of these are the ones which cause STD).
Well anyway, thank you for clarifying your germs. I don’t think I have the brainpower right now to do that other post on specific buggie-murder; I’m really tired right now and it’s past my bedtime. Maybe tomorrow if you’re all still interested.
'Night all.
Of the many answers to your question, hydrogen peroxide kills germs by oxidation. What happens to organic matter that is oxidized? Fully oxidized carbon = CO2. In reality you may get a black residue of partially oxidized carbon. Just mix hydrogen peroxide (dilute please) with oil to see the muck created.
Another important means of killing other organizisms is by poisioning them. Chlorine and other substances are common.
Perhaps the most straight-forward method is removal by physical means - either the organism or its food source directly. The swab you get before a shot may not kill anything, but it will remove oil from your skin where the germs live.
Hopefully this provides you with a few answers.
Lemme guess… pestis?
You missed some obvious ones amongst the protists: sleeping sickness, malaria, giardiarisis, dysentery.
The archae can produce opportunistic secondary infections in severe wounds (rare, but documented).
The miscellaneous odd things include chytrids which can infect human hair and fingernails.
Hey Yersinia,
A couple of points:
This link may interest you:
http://www.who.int/water_sanitation_health/GDWQ/Microbiology/Microbioladd/GDWQMicroAdd4.pdf
As a bonus, page 29 includes a couple methods of disinfection.
I am interested to know whether you consider plasmids, transposons, and transposable elements “alive.” They too are made up of genetic material that require a host cell for replication. My final question: how would you go about “killing” a plasmid?
-Apoptosis
ps. As for your name, here’s my guess:
http://www.insecta-inspecta.com/fleas/bdeath/Black.html
I see Blake beat me to the punch. However, I’m still interested in your opinion re: plasmids, etc.
-Apoptosis
I’m sure it’s poor etiquette to post 3 times in a row, but here goes.
Blake,
This caught my eye. I’ve never heard of archae referred to as human pathogens before. I couldn’t find any info on PubMed, the WHO site, or the CDC site about this. Do you have any info I could look at?
-Apoptosis
I’ll see if I can dig something up. I don’t have any refernces to hand.
IIRC there was no suggestion they were major pathogens, more that they were isolated from a wound already infected with other microbes.
Yeah, pestis.
Anyway, I distinctly recall saying at the end of that post how tired I was and that it was past my bedtime (and, “so far as I know” with regards to which of your named critters were or weren’t pathogenic to humans. But, that’s OK. You guys here seem now to have the subject in hand, so I’ll leave it all to you. Sorry I butted in.
Have fun, everyone.
OK, Apoptosis (you also have a great screen name), first things first. Thanks ever so much for the websites. I’ve bookmarked them for more thorough perusal.
Now…no, I don’t consider plasmids, transposons or transposable elements alive. I see plasmids in particular as much more like mitochondria or ribosomes – like “organelles” to a bacterium in the same way that mitochondria and ribosomes are organelles in eukaryotes; the plasmids carry genes which enable the bacteria to perform certain functions (resisting antibiotics comes strongly to mind here). Oh yeah, and yes, I know bacteria have ribosomes too.
The only way I personally know of to kill a plasmid is to kill the bacterium it’s found in. But I’m sure with a name like yours you probably already know.
Hey Yersinia,
It’s my belief that the whole viruses as living vs non-living “entities” just boils down to semantics. However, here are a couple interesting points to ponder.
Some viruses integrate their DNA into the host genome & exist as “prophages.” These prophages often confer some sort of benefit on their host (e.g. the prophage-encoded Shiga toxin of EHEC). Is this not analogous to the “life-cycle” of a plasmid?
Another thing to consider is insertion sequences (IS). Unlike transposons, IS only encode genes required for insertion. They therefore do not confer any benefit to the host, and can be considered as genetic parasites. Are they alive? Why not?
http://www.bact.wisc.edu/MicrotextBook/BactGenetics/insertionseqs.html
Heh heh. Except that bacteria don’t undergo apoptosis. wink
-Apoptosis
Ah, some lysogeny here? At least that’s the term I was taught for that when I took microbiology and virology (early and mid 90s). Anyway, I know about prophages. I also forgot to mention (WHY did I look at and post in this thread when I’m brain-dead?!) that another reason why I would say a virus is alive, but a plasmid isn’t is because you get individual viruses in the end which either bud out of their host cell’s membrane or when the host cell lyses, spewing them forth to find new host cells to commandeer, which they have to do independently – however haphazard this may be, given that they have to wander around to find cells with suitable receptors for them to bind to. A plasmid stays inside a bacterium, and the bacterium has to conjugate with another bacterium in order to pass it on (or receive new plasmids).
Insertion sequences – IMO not alive. In order for me to view something as a life form, it has to not only have its own genetic material and be able to reproduce (or replicate, if you prefer ;)), but be actually distinguishable as a distinct entity which can exist outside of a host cell, even if not for long and not able to do much of anything without that host cell.
Okay, so tell me now. Which of these are you? (1) a microbiologist or cell biologist, or (2) in college/grad school in either of those fields? I ask because I’m impressed with your questions and the technical level of the material on the websites you’ve provided.
FYI on above question: I was a pharmaceutical/cosmetics company microbiologist who did a lot of testing products (finished goods and raw materials) and water for microorganisms, although I did some antibiotic efficacy assays (don’t know if you’re familiar with the cylinder plate method). I also started and maintained stock freeze cultures of bacteria, and had a taste of doing sterilization validations too. But my specialty, and very favorite microbiological activity of all, was bacterial identification. Worked my way through most of college starting out as a media prep technician and then while still in school getting “ahead” to doing testing and IDs through taking initiative/picking up other people’s slack, working my ass off and going through a series of temp positions at different labs to get more experiences after my first lab job at a contract testing company. After nearly nine years in micro labs, I left the field almost three years ago because I couldn’t stomach the games and politics of being in a position in which I was “taken seriously” as a “professional.” And I also couldn’t deal with some of the kinds of things I saw not only tolerated, but tacitly encouraged (falsifying data, for instance).
Who me, bitter?
Well, first youse needs ta getta holda da Germ Mafia.
Afta dat, it will be taken care of…
