This is a burning question on my mind lately. As a microbiologist I've been taught that antibiotics exist for the medical profession to help treat infectious diseases, and oh yeah, for scientists to use in their experiments (for a plethora of reasons). Obviously antibiotic production didn't evolve for humans to take advantage of it....so why did it evolve?
Important things to keep in mind:
1. Antibiotics as they are used in medicine, agriculture, and aquaculture are at concentrations orders of magnitude higher than what would be produced naturally by the organisms in which their production evolved.
2. Bacteria (and other microbes) are known to exist in nature very differently than they do in the laboratory.
Bottom line:
The way(s) antibiotics affect bacteria in the lab may not be the way they affect bacteria in nature. More on this later...
May 3, 2011
Jiffy pot surprise
As I venture into my new role as amateur gardener, I am slowly realizing I have lots to learn. I was really pumped to sow some seeds indoors then transplant them when it gets warmer. So I collected some Jiffy pots from my pseudo-mom and started sowing. About one week later I noticed sprouts! Seedlings abound! But what I hadn't anticipated were the fungal cells multiplying at the same time. Now there is a furry white film around the top of my Jiffy pots. Luckily the fungal hyphae didn't extend onto the plant sprouts. I distanced the pots from one another so they could dry out better. I also turned on a space heater and sprayed them with 0.3% hydrogen peroxide. Hopefully it works!
Fungal cells or spores must have been hiding out in the Jiffy pots, waiting for moisture and nutrients. When I added the soil and water, covered the pots to keep moisture in, and left them in indirect sunlight, the fungi must have found ideal conditions for multiplication. Extensions of single cells in to mycelium networks now made a visible mark on my pots. I wonder how long they had been in the pots. Since manufacture? Or perhaps they were stored in pseudo-mom's greenhouse for too long, in an opened package nonetheless. I will never know I guess. I only wish I had microscope at home to take a closer look!
Fungal cells or spores must have been hiding out in the Jiffy pots, waiting for moisture and nutrients. When I added the soil and water, covered the pots to keep moisture in, and left them in indirect sunlight, the fungi must have found ideal conditions for multiplication. Extensions of single cells in to mycelium networks now made a visible mark on my pots. I wonder how long they had been in the pots. Since manufacture? Or perhaps they were stored in pseudo-mom's greenhouse for too long, in an opened package nonetheless. I will never know I guess. I only wish I had microscope at home to take a closer look!
May 1, 2011
Ewwww!
The often cited statistic is this: only one in ten cells of the human body is human. What are the other nine? Microbial cells. Cells from really small mites and worms, but also cells from bacteria and single-celled eukaryotes. Huh? Euk, what?
Biologists like to give fancy names to not-so-fancy differences. Of all the cells in the world, they can be divided in to two types: those with a nucleus (eukaryote) and those without a nucleus (a prokaryote). We are eukaryotes made of many cells, and can be seen without a microscope. So we're macroscopic multicellular eukaryotes. But there are also really small eukaryotes that one would need a microscope to see. We call those microbial eukaryotes. These include a lot of fungi (which can become macroscopic when cells join forces to make fruiting structures like mushrooms) and scary things like plasmodium, the cause of malaria.
Prokaryotes are all single-celled organisms, which means that they exist as individual cells. Bacteria are prokaryotes, and so are a related group of organisms called the Archaea. But back to the human body.
Only one in ten cells is human? Why don't we look like a gimush of bacteria and other microbes? Well, human cells are about 10 times bigger than bacterial cells, so we only see the human composite. But if we had microscopic vision, we'd see a whole different picture.
This is precisely what a lot of scientists are doing right now, not with microscopes, but with DNA sequencers. They're taking samples of humans and sequencing DNA to identify and classify the bacteria and other microbes present, which collectively are referred to as the 'Human Microbiome'. We want to determine the microbiome for people with different diseases (Crohn's disease, IBS, obesity, etc.) and compare them to the microbiomes of people without these diseases. These comparisons might tell us how microbiomes differ in diseased individuals so that one day we may be able to treat them by altering the microbiome ecosystem. For example, we could provide them with a beneficial bacterial species that kills a harmful bacterial species.
How do you feel about swallowing bacteria to treat disease?
Biologists like to give fancy names to not-so-fancy differences. Of all the cells in the world, they can be divided in to two types: those with a nucleus (eukaryote) and those without a nucleus (a prokaryote). We are eukaryotes made of many cells, and can be seen without a microscope. So we're macroscopic multicellular eukaryotes. But there are also really small eukaryotes that one would need a microscope to see. We call those microbial eukaryotes. These include a lot of fungi (which can become macroscopic when cells join forces to make fruiting structures like mushrooms) and scary things like plasmodium, the cause of malaria.
Prokaryotes are all single-celled organisms, which means that they exist as individual cells. Bacteria are prokaryotes, and so are a related group of organisms called the Archaea. But back to the human body.
Only one in ten cells is human? Why don't we look like a gimush of bacteria and other microbes? Well, human cells are about 10 times bigger than bacterial cells, so we only see the human composite. But if we had microscopic vision, we'd see a whole different picture.
This is precisely what a lot of scientists are doing right now, not with microscopes, but with DNA sequencers. They're taking samples of humans and sequencing DNA to identify and classify the bacteria and other microbes present, which collectively are referred to as the 'Human Microbiome'. We want to determine the microbiome for people with different diseases (Crohn's disease, IBS, obesity, etc.) and compare them to the microbiomes of people without these diseases. These comparisons might tell us how microbiomes differ in diseased individuals so that one day we may be able to treat them by altering the microbiome ecosystem. For example, we could provide them with a beneficial bacterial species that kills a harmful bacterial species.
How do you feel about swallowing bacteria to treat disease?
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