Ema
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Full text: http://blogs.scientificamerican.com/lab-rat/2012/07/08/how-fungi-steal-zinc-from-your-body/
I’ve been getting quite into the human microbiome lately, covering both vaginal bacteria and digestive tract bacteria. One thing I thought it might be interesting to highlight is that we talk about the human “microbiome” rather than the human “bacteriome” because it contains a range of microbial species including bacteria, fungi and even possibly blastocysts. There’s more life in your body than you might think.
So with this in mind I’m going to venture forth into the world of fungi.
Candida albicans lives naturally on the human body in the mouth, intestines and around the urinary and reproductive areas. In normal circumstances they live there quite happily, however if they start to overgrow for any reason (such as if you’re taking antibiotics and remove the competing bacteria) they can cause an infection. Infections are usually cleared with a simple course of antifungals, either as a cream or as a tablet. Like all internal micro-organisms C. albicans faces challenges living within a human body, most noticeably the need for trace metal elements. While these are fairly easy to find in a soil environment, they are harder to get hold of inside a body.
One of the most famous human fungi, Candida Albicans, growing on a petri-dish. Content Providers(s): CDC/Dr. William Kaplan Creation Date: 1969
In a recent PLoS Pathogens paper (reference 1 below) C. albicans cells were starved of zinc, and then grown either with or without the close proximity of human endothelial cells (the cells that line the inside of the human gasterointestinal tract). They used hyphal growth as a measure of overal fungal growth, the hyphae are the branching filamentous structures as shown in the picture below:
What the researchers found was that fungi next to human cells were growing faster and longer hyphae than those growing alone. Furthermore, this growth effect could be replicated by adding a zinc supplement to the lonely cells. From this primary observation they explored further, injecting the human cells with a dye that specifically colours zinc (zinquin – which actually adds a fluorescent label to the zinc). When tested, some of the dye was found inside the newly grown hyphae. The fungi seemed to be picking the zinc up from the human cells.
The hyphae of penicillium, showing the branching structure. You can also see the upright fruiting bodies with spores on the end (they look like little trees!) Creative Commons licence, credit link below.