yesterday i finished artschool and now i am roaming around in a lab coat having a pretty serious summer job in a microbiology / physical chemistry lab for 36 hrs a week. The contrast is huge. (on another note they all wanted me to talk about art and to look at my website and the stuff that i make)
Deinococcus radiodurans - the bacterial nuclear survivor
So on the topic of extremophiles after some of you guys really wanted to hear about crazier organisms than the tardigrade. D. radiodurans is one of my favourites because it can survive an insane number of extreme climates and no-one is quite sure the exact reason as to why such an organism evolved leading some scientists to believe it may have colonised Earth through panspermia (although its genetic make-up is to similar to that of other organisms for this to be a viable reason). It was identified in 1956 when scientists were experimenting with gamma radiation as a means of sterilising canned foods. a can of food exposed to gamma radiation thought to kill all forms of life spoiled due to this microbe.
D. radiodurans has a number of nifty little adaptations that help it withstand up to 5000Gy of ionising radiation with little loss in viability. For one, you can see in the image above that the spherical cells form a tetrad. Each cell within the tetrad also contains 4 identical circular copies of the genome. So each tetrad has 16 identical copies of the same genome. What this allows for is homologous racombination, to allow repair of broken fragments of DNA. The cells in the tetrad frequently take up fragments on DNA from neighbouring cells to improve repair.
So why has such an ability evolved? It is unlikely that such conditions have ever existed on Earth as few other organisms can survive anywhere near the same amount of radiation, but the ability to repair its DNA so well is most likely a lucky evolutionary accident that has stemmed from it resistance to dessication in incredibly dry environments as the mechanisms with dealing with both are highly similar.
This bacteria is also able to withstand cold and acidic environments as well as vacuums. Current applications for the bacteria include using it in bioremediation to clear up radioactive, polluted sites where solvents and other toxic compounds contaminate the area.
The vanillin (major flavor compound in vanilla beans) found in most food products on the market is derived from a three-step synthetic process that converts the molecule guaiacol to vanillin. Both natural and chemical methods for this conversion has shown to be expensive and environmentally burdensome, but biotech company Gen9 is providing a more promising route to synthesize vanillin that begins with glucose, using yeast to “ferment it just like beer.“ David Chang of Momofuku and microbiologist Ben Wolfe further elaborate on how microbes may very well be the future of food. What we’re reading…
Coloured scanning electron micrograph (SEM) of assorted diatoms. The diatoms are a group of photosynthetic, single-celled algae containing about 10,000 species. They form an important part of the plankton at the base of the marine and freshwater food chains. The characteristic feature of diatoms is their intricately patterned, glass-like cell wall, or frustule. The frustule often has rows of tiny holes, known as striae.
A photo of the green alga Volvox globator from the Dodel-Port Atlas, circa 1880.
Volvox globator exists as a spherical colony of individual single-celled organisms, each with two whip-like appendages called flagella that V. globator uses to propel itself around. The cells are stuck together by thin strands of cytoplasm, allowing them to move in concert to direct the colony’s motions.
Glen Ronaldwas born and raised in1969 in Manitoba, Canada. After getting a degree in microbiology, the pull of art was strong and he decided to go to art school. A year of study and experimentation and lots of academic and group shows led to a scholarship to further study art. But he chose to study education instead and began a long study of chaos in his spare time. That’s when his current style began to come into being. Glen’s paintings are called chaosmos, for he creates a field of chaos and pulls the cosmos out of it. There is a dynamic rush of realism pushing against abstraction via.
CrossConnectMag on Facebook - a place that is definitely worth a visit!
These ‘Resurrection Plants’ Spring Back to Life in Seconds | Deep Look
Our newest episode of DeepLook, our macro science series in partnership with pbsdigitalstudios is available for your viewing pleasure!
“Rain falls and within seconds dried-up moss that’s been virtually dead for decades unfurls in an explosion of green. The microscopic creatures living in the moss come out to feed. Scientists say the genes in these “resurrection plants” might one day protect crops from drought.”
Hello. Your blog is so amazing!! I need your advice.. I have a big exam after one month and there's a huge quantity to cover.. I don't know from where to start. The subjects are: anatomy, biochemistry, physiology, sociology, microbiology, psychology, pathology. I'm lost.. Please help me :(
H5N1 avian influenza virus particles, coloured transmission electron micrograph (TEM). Each virus particle consists of ribonucleic acid (RNA), surrounded by a nucleocapsid and a lipid envelope (green). The natural hosts of this virus are wild birds, which show few symptoms. However, infected domestic birds suffer a 90-100% mortality rate. Humans that have contact with infected birds can become infected. The first such infection was identified in South-East Asia in 1997, and the virus has steadily spread across the world, with an outbreak in a poultry farm in the UK in 2007. There are fears that the virus may mutate into a human-transmissible form, which could lead to millions of deaths worldwide. Magnification: x670,000 when printed 10cm wide.
Nearly finished with this after having it in my library for so long. Looking forward to sharing it with all of you, because it’s one of the most brilliantly written compositions of poetic literature I’ve experienced since the first time I read Sagan and Darwin.
Bacteria “know” where to divide into daughter cells using a concentration gradient formed by the protein MinD, which oscillates back and forth in a rod-shaped cell with maxima at the ends and minima in the middle, where the cell divides. Here’s a figure of it in action with green-fluorescent protein-tagged MinD in an E.coli cell over time:
Researchers from the Netherlands have pushed the limits of how MinD is able to define the cell division boundary by custom-growing E.coli cells into different shapes and sizes. This required chemically suppressing the E.coli’s ability to maintain its rod shape and form a new cell wall between the dividing cells, and then injecting a single cell into bacterium-scale (micrometer, or um) moulds of the desired shape, which they would then expand to fill:
Again, using GFP-tagged MinD its oscillations were tracked over time in the artificially shaped cells. Definite patterns could be seen, with the MinD preferring to travel along symmetry axes:
The cell dimensions of rectangular cells were systematically altered and different patterns were observed, with one common characteristic -for cell lengths of ~3-6um, about the length of normal dividing E.coli cells, MinD forms 2 poles. Multiple poles appeared at 7um or greater, and lack of poles occurred at <2.5um.
The protein dynamics underlying this can be modeled by Turing’s reaction-diffusion equations
Although Turing is mostly known for his role in deciphering the Enigma coding machine and the Turing Test, the impact of his ‘reaction-diffusion theory’ on biology might be even more spectacular. He predicted how patterns in space and time emerge as the result of only two molecular interactions – explaining for instance how a zebra gets its stripes, or how an embryo hand develops five fingers. Such a Turing process also acts with proteins within a single cell, to regulate cell division.
Pyrolobus Fumarii - Is it me or is it Getting Warm in Here?
In 1996 an irregularly coccoid-shaped archaeon (top image) was isolated from a
hydrothermally heated ‘black smoker’ (bottom image) at the Mid Atlantic Ridge. The archaeon was
found to grow between 90 – 113˚C (optimum 106˚C) and at a
pH of 4.0 – 6.5 (optimum 5.5). Pressures at this depth were also about 250
times that of the surface. This organism is Pyrolobus
fumarii which is the most hyperthermophilic organism we know about.
How is it possible for such an organism to exist? These aren’t
the only hyperthermophiles that reside in incredibly hot conditions on the
planet, with a number of organisms taking residence around hydrothermal vents
across the globe. There are a number of physiological and biochemical adaptions that organisms
such as P. fumarii have evolved to withstand such temperatures. The microscopic
size of these microorganisms means that there is little surface area available
for insulation, so molecules produced inside these cells must be
adapted to the hot environment. Above 100˚C, many biological molecules will easily break
down, so a number of other strategies need to be employed to reinforce cellular
structures to protect them against the surrounding temperatures.
A common way of doing this is to bias the amino acids that
make up their proteins, to contain a large number of hydrophobic
residues within their structure. Hydrophobic interactions between these and the
surrounding water molecules will help to keep the protein core condensed,
preventing denaturation. Many hyperthermophiles including P. fumarii have
different lipid membranes to most other organisms. They contain dialkyl
glycerol tetraethers which are covalently linked which prevents dissociations
of the lipid membrane. The final way these organisms generally protect
themselves is by using heat stable chaperone proteins. Chaperones will bind
denatured proteins preventing their aggregation, and promote refolding.
The hyperthermophiles along with most of the extremophiles represent
a largely unexplored area of biotechnological exploitation. Heat stable
proteins that can remain active at temperatures of 130˚C would be highly useful
in the food and biochemical industries.