Growth-coupled microbial biosynthesis of the animal pigment xanthommatin
TL;DR
Imagine you want to teach bacteria to make a valuable pigment (a coloring compound) that normally comes from animals. The problem is that bacteria are usually lazy - they don't want to waste energy making something they don't need. These scientists solved this by creating a clever "deal" with the bacteria: as the bacteria make the pigment, they also produce a nutrient (formate) that they desperately need to survive and grow. It's like telling the bacteria "the more pigment you make, the more food you get." This creates a positive feedback loop where making the desired product actually helps the bacteria thrive, so they're motivated to make lots of it. The result? They can now produce gram quantities (enough to see and use) of this complex animal pigment using just sugar and engineered bacteria.
Engineering heterologous natural product pathways in bacteria has achieved broad success but most approaches suffer from low initial production levels that require extensive, resource-heavy iterative strain optimization. Xanthommatin is a structurally complex, color-changing animal ommochrome with material and cosmetic applications, yet production in microbial cell factories has been difficult. Here, we introduce a growth-coupled biosynthetic strategy involving a feedback loop where an excised one-carbon (C1) moiety is used as a driver of bacterial growth, simultaneously boosting bioproduction of the target compound. This broadly applicable, plug-and-play strategy is illustrated by enabling xanthommatin biosynthesis in a 5,10-methylenetetrahydrofolate auxotroph of the platform soil bacterium Pseudomonas putida. In this design, formate released during xanthommatin production relieves the C1 deficiency, thereby effectively coupling bacterial growth to pigment synthesis. Adaptive laboratory evolution streamlined xanthommatin's gram-scale bioproduction from glucose, establishing C1 restoration as a general biosynthetic approach to accelerate the engineering of natural product biosynthesis in bacteria.
- 1Developed a growth-coupled biosynthetic strategy using a feedback loop where an excised one-carbon moiety drives bacterial growth while boosting target compound production
- 2Successfully engineered xanthommatin biosynthesis in a 5,10-methylenetetrahydrofolate auxotroph of Pseudomonas putida by coupling formate release to growth
- 3Achieved gram-scale bioproduction of xanthommatin from glucose through adaptive laboratory evolution
- 4Established C1 restoration as a general biosynthetic approach to accelerate natural product engineering in bacteria
- 5Demonstrated that formate released during xanthommatin production relieves C1 deficiency, effectively coupling bacterial growth to pigment synthesis
Single-minus gluon tree amplitudes are nonzero
Imagine tiny particles called gluons are like spinning tops. Their spin can be in one of two directions, which physicists call 'plus' or 'minus'. For decades, the rulebook seemed to say that you could never have a situation where just one gluon was spinning 'minus' and all the others were spinning 'plus' — that outcome was thought to be zero. This paper found a loophole. Under very specific, purely mathematical conditions that don't exist in our physical reality but are useful for calculations, this interaction can happen. The researchers wrote down the exact recipe for it, fixing a small but important detail in our fundamental rulebook for how the universe works.
Sub-part-per-trillion test of the Standard Model with atomic hydrogen
Scientists made an incredibly precise measurement of light emitted by hydrogen atoms that tested one of physics' most fundamental theories - the Standard Model - to an accuracy of 0.7 parts per trillion. This measurement also resolved a long-standing disagreement about the size of protons by confirming the smaller value found in previous experiments with exotic atoms.
Rock art from at least 67,800 years ago in Sulawesi
Imagine finding a spray-painted handprint on a cave wall. Over thousands of years, a thin, glassy layer of minerals, like limescale in a kettle, grew on top of it. Scientists used a high-tech laser to analyze that mineral layer. By measuring the natural radioactive decay of elements within it, they figured out the layer is about 71,600 years old. Since the handprint is underneath that layer, it must be at least that old, with the most conservative estimate being 67,800 years. This makes it one of the oldest pieces of art ever found and proves that the early humans who lived on this Indonesian island, who had to cross the ocean to get there, were creating symbolic art.
An interstellar energetic and non-aqueous pathway to peptide formation
Imagine you have a box of LEGO bricks, which are like the basic molecules of life called amino acids. To build anything, you need to snap them together. Scientists used to think you needed a puddle of liquid water to make the bricks 'click'. This experiment is like discovering you can snap the LEGOs together inside a freezer. The researchers took the simplest amino acid, froze it onto a dust grain like you'd find in space, and zapped it with energy that mimics cosmic radiation. They found that the amino acids linked up to form a two-brick chain, the first step towards building a protein. This means the essential first chains for life could be forming all over space and delivered to new planets by comets and asteroids.