RESEARCH HIGHLIGHTS Scientific Literature

Selections from the RESEARCH HIGHLIGHTS scientific literature

CARDIOVASCULAR BIOLOGY Gut microbes raise heart-attack risk Gut microbes produce a chemical that enhances clotting in the arteries, increasing the risk of heart ONOZATO/AFLO/GETTY TAKAO attack and stroke. Stanley Hazen of the Cleveland Clinic in Ohio and his colleagues treated human platelets, which form blood clots, with a compound called TMAO. This is made in the body from a waste product of gut microbes, and has been linked to heart disease. The team found that TMAO made the platelets form artery-blocking clots faster. The researchers increased blood TMAO levels in mice ANIMAL BEHAVIOUR by feeding them a diet that was rich in choline, a TMAO precursor, and found that the Order of notes is key in bird calls animals formed clots faster than did those with lower A bird species derives different meanings from its calls. Playing ABC prompted the birds to scan TMAO levels. varying combinations of notes, just as humans horizontally for predators. On hearing a repeated This effect was not seen understand complex meanings from words D note, the birds approached the source of the in animals that lacked gut combined in different ways. calls. ABC–D calls elicited both behaviours, but microbes or that were treated Toshitaka Suzuki of the Graduate University playing D–ABC invoked little or no response. with antibiotics. When for Advanced Studies in Hayama, Japan, and The authors suggest that the order of the intestinal microbes from mice his colleagues played recordings of four notes notes determines meaning, and say that that produced high levels of — A, B, C and D — in different orders for the this is the first experimental evidence for TMAO were transplanted into Japanese great tit (Parus minor; pictured), which ‘compositional syntax’ in a wild animal. mice with no gut microbes, normally uses more than ten different notes in Nature Commun. 7, 10986 (2016) the recipients’ clotting risk increased. The results reveal a link between diet, gut process that uses bioreactors gases that are generated by often overexpressed in cancer microbes and heart-disease to create liquid fuel out of industrial sites such as steel — in a mouse model of a type risk, the authors say. gas mixtures containing mills and coal-fired power of leukaemia. They found that Cell http://doi.org/bdb2 (2016) CO2. The first stage involves plants, the authors say. higher MYC expression levels the bacterium Moorella Proc. Natl Acad. Sci. USA increased the production CHEMICAL ENGINEERING thermoacetica, which http://doi.org/bdb5 (2016) of two proteins, PD-L1 and converts mixtures of CO2 and CD47, that help cancer cells Waste gas makes other gases such as carbon CANCER to hide from the immune liquid fuel monoxide or hydrogen into system. When MYC was acetic acid. An engineered Gene blocks anti- inactivated, CD47 and PD-L1 Waste gases containing carbon yeast, Yarrowia lipolytica, tumour response levels dropped and tumour dioxide can be converted into then transforms the acetic size decreased. Tumour data diesel, thanks to a bacterium acid into an oil that can be A common cancer gene works from humans showed a strong and an engineered yeast. turned into diesel using in part by helping tumours to link between levels of MYC Gregory Stephanopoulos existing industrial processes. evade immune cells. expression and levels of these and his colleagues at the This method, with further Dean Felsher of Stanford immune-evasion signals. Massachusetts Institute of enhancements to boost University in California and People with cancers that Technology in Cambridge efficiency, could be used to his colleagues studied the overexpress MYC could developed a two-stage produce fuel from the waste effects of MYC — a gene that is benefit from treatments that

boost the immune attack MICROBIOLOGY against tumours, the authors suggest. Bacterial toxins ESO/F. CHAR ESO/F. Science http://doi.org/bc7p invite infections (2016) Certain pneumonia-causing NEUROSCIENCE bacteria produce compounds that help other pathogenic Altered sensations bacteria to spread through in anxiety the lungs. Bret Sellman at Anxiety disorders could MedImmune, a biotechnology involve not only cognitive, firm in Gaithersburg, but also sensory changes in Maryland, and his colleagues the brain. infected mice with a variety Recent studies have of bacterial species, either suggested that people with individually or in combination anxiety, after learning a with Staphylococcus aureus, negative stimulus, respond which can cause respiratory flight, anchoring the insects to Valenti says that this is the negatively to similar but and other infections. Mice the water. first study of the bulge based neutral stimuli more often that were co-infected with Keeping four of their six entirely on observation, without than healthy people. Rony S. aureus had higher levels of legs on the water, the insects the help of theoretical models. Paz at the Weizmann Institute both microbe species in their use the fluid’s surface tension Astron. Astrophys. 587, L6 (2016) of Science in Rehovot, Israel, lungs, and were more likely to to support their body weight and his colleagues found die than animals infected with and move by flapping their LONGEVITY that individuals with anxiety a single pathogen. The team hind wings, cruising along disorders also perceive these found that a protein produced the water’s surface at speeds of Genetic switches stimuli less precisely than by S. aureus, called α-toxin, aids up to half a metre per second. for long life healthy people do. After the growth of several bacterial Moving any faster would learning to associate a tone species by impairing immune- render them airborne, because Researchers have homed in on with either monetary gain or cell function. Early treatment the ripples they produced on the genetic control points that loss, participants were asked with an antibody against the water would release their allow nematodes to live longer to decide whether a series of α-toxin helped to eliminate anchors. when they are on a low-calorie other sounds were a match to S. aureus and prevented other J. Exp. Biol. 219, 752–766 (2016) diet. the previous ones or were new. pathogens from multiplying. A team led by Jing-Dong People with anxiety disorders The authors suggest that ASTRONOMY Han of the Chinese Academy of mistook a wider range of antibody-based treatments Sciences in Shanghai analysed frequencies for the tones they targeting a single bacterial Milky Way’s gene-expression changes had learned, compared with species could help some people bulging waistline over time in the nematode healthy people. Learned tones who are infected with multiple Caenorhabditis elegans. The and neighbouring sounds pathogens. The mass of stars in the Milky worms were subjected either triggered brain activity that Sci. Transl. Med. 8, 329ra31 Way’s central bulge (pictured) to caloric restriction or to showed greater similarity in (2016) is about 20 billion times the intermittent fasting, both of people with the disorders than mass of the Sun — a much which extend worm lifespan. in healthy people. This effect BIOMECHANICS higher estimate than in most The team identified changes was in the brain’s auditory previous studies. in the expression of various cortex and in the amygdala, How flying The central bulge protrudes genes at different times, with which processes fear. beetles waterski from the Galaxy’s main disk metabolism genes responding The findings suggest that like the yolk of a fried egg early during the diet, and people with anxiety have The waterlily beetle exploits and hosts a large density of those linked to cell division altered perception of certain properties of the interface stars. To estimate the mass and DNA repair changing later stimuli, the authors say. where air and water meet of those stars, Elena Valenti on. The researchers then used Curr. Biol. http://doi.org/bc3z to glide quickly across the at the European Southern an algorithm to identify three

MATTIAS LANAS MATTIAS (2016) surface of ponds. Observatory (ESO) in sets of genes that regulate this Manu Prakash at Stanford Garching, Germany, and her altered expression. Changing University in California team used a catalogue of stars the activity of the pathways and his colleagues filmed of a particular type. The data controlled by these genes waterlily beetles (Galerucella are from ESO’s Visible and extended the lifespan of the nymphaeae; pictured) at Infrared Survey Telescope for worms, mimicking the effect 3,000 frames per second to Astronomy (VISTA) at the of dietary restriction. characterize the mechanics of Paranal Observatory in Cell Metab. 23, 529–540 (2016) the insect’s unusual mode of Chile. The team also did flight on the two-dimensional a deeper study of all the NATURE.COM surface. They found that stars in a small region of the For the latest research published by the claws on the beetles’ legs bulge, in part using the Hubble Nature visit: remain submerged during Space Telescope. www.nature.com/latestresearch