Lost & Found #5
by Christoph
When you leave 𝕏 (formerly Twitter), it means that among the "bookmarks" you take with you, you will also come across some that contain images or videos that are mainly nice to look at and even entertaining. As in Lost & Found #4, two such are included today in Lost & Found #5.
Bookmark #1
It's old hat that beta-lactam antibiotics such as amoxicillin inhibit cell wall synthesis, specifically the synthesis of peptidoglycan (PG), and thus cause growing cells to burst. What remains is debris. You have certainly already been shown such images in your basic microbiology course. Here Jan-Willem Veening shows a particularly impressive example in his tweet. The legend to Figure 3 J in the corresponding paper informs you that this 7‑second video is the time-lapse of a 6‑hour experiment. It shows the growth of a S. pneumoniae mutant strain where the first mevalonate operon was depleted (VL3709), which results in elongated cells due to impaired Und‑P synthesis, growing on agarose pads of C+Y medium without the inducer IPTG. To fully appreciate the tweeted video, I recommend you read the paper from which it was taken.
Of particular interest in the paper is Video 6 in which the growth of Amoxicillin‑reistant S. pneumoniae D39V (VL333) and its response to the addition of antibiotics was tested individually and in combination. It is really convincing how efficiently the addition of 8 µg/ml clomiphene (Clom) – an inhibitor of Und‑P synthesis – "boosted" the effect of 0.016 µg/ml Amoxicillin (Amx).
Using the antibiotic amoxicillin in combination with a fertility drug boosts it's ability to kill normally resistant bacteria. https://t.co/hoOk1PB34H pic.twitter.com/dNRG7VvR01
— eLife — the journal (@eLife) September 11, 2022
If the tweet is no longer available, you can see a screen capture here, and the video here (MP4).
Bookmark #2
How long do you think it took this Cladonia subtenuis, which occurs along the North American east coast, from Florida to Nova Scotia, to reach this shape, affectionately called a "full moon"? For related lichen species, Richard Troy McMullin has measured growth rates of ~5 mm per year in northern latitudes. Learn more about this lichen that is also known as Dixie Raindeer Lichen here, and here you can see a picture in which you can recognize the tiny apothecia if you look closely.
For each full moon I am doing a #fullmoonlichen photo share. Lichens are often called moss but they are symbiotic organisms made of a fungus + cyanobacteria.
Post a pic of a lichen, name if you know, use #fullmoonlichen & I'll RT all.
This is #Cladonia subtenuis, from Georgia pic.twitter.com/wWcM6WkWTD
— Lyrae Willis (@lyraenatureblog) January 6, 2023
If the tweet is no longer available, you can see a screen capture here, and the image here.
Bookmark #3
Already five years ago, in a tweet form 2019, the 'Deep Carbon Observatory' made their magnum opus public: "in celebration of the accomplishments of scientists over the past 10 years, a new Open Access book – Deep Carbon: Past to Present." While still available, check the complete tweet, and even better: get this book if you are interested in biogeochemistry and subsurface microbiology.
I pick just two aspects here. Given their (estimated) numbers (Image 1), the sub-surface dwelling microbes should give us microbiologists a reason to "recalibrate" what we commonly understand as "extreme" conditions for life (high/low temperature, high acidity (low pH)/high alkalinity (high pH), high salinity). We certainly need to include "piezo-tolerance" (baro-tolerance) (Image 2). "The biomass in high-pressure environments may exceed that on the surface. ... In the deep subcontinental crust, the total volume in the hydrated fissures in the rock is a large proportion of the biosphere, estimated to be 1,016 m3 and 23–31 Pg (1015 g) of carbon. If only 1% of that volume is occupied by microorganisms, their biological productivity could be greater than that of Earth's surface. It is truly remarkable that life manages to exist in such extreme environments compared to the benign conditions in which humans exist." (ref.)
How does life survive under extreme conditions underground and below the sea? Do #deepbiosphere microbes possess unique genes or proteins that might have utility for humanity? Check out chapter 18 of the FREE #deepcarbonbook to find out: https://t.co/DNOtQID7Ai pic.twitter.com/u7ZMLa0erq
— Deep Carbon Obsrvtry (@deepcarb) December 10, 2019
If the tweet is no longer available, you can see screen captures here and here, and the images here and here.
Legend to image 1. Estimated numbers of bacteria and archaea throughout various biomes. Cellular estimates for the subsurface, soils, oceans, and animal guts are illustrated to show the relative sizes of each biome. See Source (Chapter 17.2) for the references.
Legend to image 2. Average fluorescence intensity images of GFP-Mrr expressed from an aranbinose-inducible promoter (PBAD) at the natural chromosomal locus in E. coli MG1655. (Left) Cells prior to the application of pressure. Full scale is 0–1.48 photon counts per 40 µs. (Right) After 10 minutes at 1 kbar and release of pressure. Full scale is 0.5–6.7 photon counts per 40 µs. Both images are 20 × 20 µm. Source
