In this week’s Sunday Science some nice medical advances: a promising new HIV vaccine trial, approval of a drug for ovarian cancer and a potential game-changer with gene edited blood cells to treat blood disorders that affect millions of people. Also: spooky green fluorescent sharks, our twisted galaxy, green energy, and embryo development.

By calculating the brightness of individual supergiant stars, researchers have generated a new 3D map of the Milky Way (see featured image), highlighting that its characteristic spiral arms are twisted. Original research paper, for the astronomers, may be found here (but behind the Science paywall).

A new vaccine against HIV is going to be trialled in high-risk groups across the Americas and Europe. Researchers have struggled to make a vaccine against this deadly disease because the virus mutates so quickly. HIV is a retrovirus, meaning it’s genetic material is made of RNA and it must copy this from the DNA it hijacks in the cells it infects – essentially doing it “backwards” compared to most organisms. The enzyme it uses to do this is very inaccurate, meaning it introduces errors and mutates very rapidly. Over 100 vaccines have been (unsuccessfully) generated against HIV, but it’s a moving target given that it changes so fast. The researchers hope this one, which is generated from a “mosaic” of all the different subtypes of HIV found around the world, will give at least 65% protection over a number of years.

A  drug to treat ovarian cancer has been approved for early use by NICE in the UK. Olaparib is effective when given to those recently diagnosed patients who have a mutation in the BRCA gene, which predisposes them to this type of cancer. Ovarian cancer is often diagnosed late, meaning it is difficult to treat. In clinical trials this drug delayed progression of the disease for up to three years, which is a significant improvement. It works by targeting a DNA repair enzyme that the cancer cells are particularly dependent on.

For the first time, scientists have used gene editing in blood stem cells to try and treat serious hereditary blood disorders such as thalassaemia and sickle cell disease, which are caused by defective production of the oxygen-carrying protein haemoglobin. What the researchers did was use CRISPR-Cas9 gene editing to keep the fetal form of haemoglobin switched on (this has a higher affinity for oxygen than the adult version, because it has to get oxygen from the mother’s blood supply across the placenta, rather than directly from the air across the lung cell membranes, but naturally is switched off after about 1 year of age). The edited red blood cells produced from the stem cells were successfully engrafted back in the primate model they were using, and produced fetal haemoglobin for at least a year. These very promising results are expected to lead to clinical trials in humans. Original research paper here (paywalled).

“Glowing green sharks” sounds like a sentence that should also include “Genetically engineered” and “devour mankind!” like some schlocky B movie (which I confess I would probably watch…) but they are in fact real, and not genetically engineered. Or going to eat anyone. These catsharks have a type of fluorescence that’s based on chemically a completely different mechanism from that found in the famous GFP (green fluorescent protein) of jellyfish, that revolutionised biological research. This is interesting in itself, but it also seems it plays a role in shark recognition and may have anti-microbial properties. Original research paper here (open access). Oh, and go on then, have a picture (there’s also a nice and rather spooky video at that last link):

Basic RGB
Derived from Park et al, 2019, iScience journal. https://doi.org/10.1016/j.isci.2019.07.019

For a change I’m going to give you some (very modest) good climate change news – well, renewable energy news, anyway. Beatrice Offshore Wind Farm, the largest wind farm in Scotland, has just been opened. On time and under budget too. It can provide enough energy for up to 450,000 homes. If you think that £2.65 billion is quite a lot of money, then consider also this report that re-directing just 10-30% of the subsidies currently pouring into the planet-killing fossil fuel industry into renewable energy could fuel a green revolution.

And finally, a former student sent me a link to this absolutely gorgeous timelapse video of a salamander embryo developing from a single fertilised egg into a hatching larva. The resolution is really impressive: you can at several points watch individual blood cells going around the blood vessels. Watch the cells first divide many times (getting smaller each time), then start folding inwards as the embryo undergoes gastrulation to form the gut and the three main layers of the body. Next, the future spinal cord starts forming up, with muscle blocks developing, future limbs start budding out…and the future animal takes shape.

 

Featured image

A 3D structure map of the Milky Way, mapped using ultra-bright stars called Cepheids. Credit: Jan Skowron/OGLE/Astronomical Observatory, Univ. Warsaw via Science publishing.

Shark image

Park et al, 2019: Bright Green Biofluorescence in Sharks Derives from Bromo-Kynurenine Metabolism. iScience, Cell Press. https://doi.org/10.1016/j.isci.2019.07.019

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