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Science Progress (2014), 97(4), 399 – 406 Doi: 10.3184/003685014X14167502018332

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science news NASA rocket finds the universe brighter than we thought A NASA sounding rocket experiment has detected a surprising surplus of IR light in the dark space between galaxies, a diffuse cosmic glow as bright as all known galaxies combined. The glow is thought to be from orphaned stars flung out of galaxies. The findings redefine what scientists think of as galaxies. Galaxies may not have a set boundary of stars, but instead stretch out to great distances, forming a vast, interconnected sea of stars. Observations from the Cosmic Infrared Background Experiment, or CIBER, are helping settle a debate on whether this background IR light in the universe, previously detected by NASA’s Spitzer Space Telescope, comes from these streams of stripped stars too distant to be seen individually, or from the first galaxies to form in the universe. “We think stars are being scattered out into space during galaxy collisions,” said Michael Zemcov, lead author of a paper published in the journal Science, describing the results from the rocket project and an astronomer at the California Institute of Technology and NASA’s Jet Propulsion Laboratory in Pasadena, California. “While we have previously observed cases where stars are flung from galaxies in a tidal stream, our new measurement implies this process is widespread.” Using suborbital sounding rockets, which are smaller than those that carry satellites, CIBER captured wide-field pictures of the cosmic IR background at two IR wavelengths shorter than those seen by Spitzer. Because our atmosphere itself glows brightly at these particular www.scienceprogress.co.uk

wavelengths of light, the measurements can only be done from space. During the CIBER flights, the cameras launch into space, then snap pictures for about seven minutes before transmitting the data back to Earth. Scientists masked out bright stars and galaxies from the pictures and carefully ruled out any light coming from more local sources, such as our own Milky Way galaxy. What’s left is a map showing fluctuations in the remaining IR background light, with splotches that are much bigger than individual galaxies. The brightness of these fluctuations allows scientists to measure the total amount of background light. To the surprise of the CIBER team, the maps revealed a dramatic excess of light beyond what comes from the galaxies. The data showed that this IR background light has a blue spectrum, which means it increases in brightness at shorter wavelengths. This is evidence the light comes from a previously undetected

Time-lapse photo of the CIBER rocket launch, taken from NASA’s Wallops Flight Facility in Virginia in 2013. Photo courtesy of T. Arai, University of Tokyo. Science news

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population of stars between galaxies. Light from the first galaxies would give a spectrum of colours that is redder than what was seen. “The light looks too bright and too blue to be coming from the first generation of galaxies,” said James Bock, principal investigator of the CIBER project from Caltech and JPL. “The simplest explanation, which best explains the measurements, is that many stars have been ripped from their galactic birthplace, and that the stripped stars emit on average about as much light as the galaxies themselves.” Future experiments can test whether stray stars are indeed the source of the IR cosmic glow. If the stars were tossed out from their parent galaxies, they should still be located in the same vicinity. The CIBER

team is working on better measurements using more IR colours to learn how stripping of stars happened over cosmic history. The article “On the origin of nearinfrared extragalactic background light anisotropy” by Michael Zemcov, Joseph Smidt, Toshiaki Arai, James Bock, Asantha Cooray, Yan Gong, Min Gyu Kim, Phillip Korngut, Anson Lam, Dae Hee Lee, Toshio Matsumoto, Shuji Matsuura, Uk Won Nam, Gael Roudier, Kohji Tsumura, and Takehiko Wada was published in Science 7 November 2014, 732 – 735; doi:10.1126/ science.1258168. For more information on NASA’s sounding rocket experiments, visit: http://www.nasa.gov/mission_pages/ sounding-rockets/. For more information about CIBER, visit: http://ciber.caltech.edu/rocket.html

Reprogrammed cells grow into new blood vessels By transforming human scar cells into blood vessel cells, scientists at Houston Methodist Research Institute may have discovered a new way to repair damaged tissue. The method, described in an upcoming issue of Circulation appeared to improve blood flow, oxygenation, and nutrition to areas in need. Cardiovascular scientists at Houston Methodist, with colleagues at Stanford University and Cincinnati Children’s Hospital, learned that fibroblasts – cells that causes scarring and are plentiful throughout the human body – can be coaxed into becoming endothelium, an entirely different type of adult cell that forms the lining of blood vessels. “To our knowledge, this is the first time that trans-differentiation to a therapeutic cell type has been accomplished with a small molecules and proteins,” said Houston Methodist Research Institute Department of Cardiovascular Sciences Chair John Cooke, the study’s principal investigator. “In this particular case, we’ve found a 400

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way to turn fibroblasts into ‘shapeshifters’ nearly on command.” Cooke said the regenerative medicine approach provides proof-of-concept for a small molecule therapy that could one day be used to improve the healing of cardiovascular damage or other injuries. Other research groups have managed to generate endothelial cells using infectious virus particles specially engineered to deliver gene-manipulating DNA to cells. The DNA encodes proteins called transcription factors to alter gene expression patterns in such a way that cells behave more like endothelial cells. “There are problems with using viruses to transfer genes into cells,” Cooke said. “This gene therapy approach is more complicated, and using viral vectors means the possibility of causing damage to the patient’s chromosomes. We believe a small-molecule approach to transforming the cells will be far more feasible and safer for clinical therapies.”

The new method described by Cooke and his coauthors starts with exposing fibroblasts to poly I:C (polyinosinic : polycytidylic acid), a small segment of double-stranded RNA that binds to the host cell receptor TLR3 (tolllike receptor 3), tricking the cells into reacting as if attacked by a virus. Cooke and coauthors reported to Cell in 2012 that fibroblasts’ response to a viral attack – or, in this case, a fake viral attack – appears to be a vital step in diverting fibroblasts toward a new cell fate. After treatment with poly I:C, the researchers observed a reorganisation of nuclear chromatin, allowing previously blocked-off genes to be expressed. The fibroblasts were then treated with factors, such as VEGF, that are known to compel less differentiated cells into becoming endothelial cells. About 2% of the fibroblasts were transformed from fibroblasts into endothelial cells, a rate comparable to what other research groups have accomplished using viruses and gene therapy. But Cooke said preliminary, as‑yet-unpublished work by his group suggests they may be able to achieve transformation rates as high as 15%. “That’s about where we think the yield of transformed cells needs to be,” Cooke said. “You don’t want all of the fibroblasts to be transformed – fibroblasts perform a number of important functions, including making proteins that hold tissue together. Our approach will transform some of the

scar cells into blood vessel cells that will provide blood flow to heal the injury.” In a second part of the study, the scientists introduced the transformed human cells into immune-deficient mice that had poor blood flow to their hind limbs. The human blood vessel cells increased the number of vessels in the mouse limb, improving circulation. “The cells spontaneously form new blood vessels – they self-assemble,” Cooke said. “Our transformed cells appear to form capillaries in vivo that join with the existing vessels in the animal, as we saw mouse red blood cells inside the vessels composed of human cells.” Cooke noted that it is likely that modifications of this small molecule approach may be used to generate other body cells of therapeutic interest. “What we are seeing is evidence of the fluidity of cell fate with the proper stimulation. If we can understand the underlying pathways and how to manipulate them, we may very well learn how reawaken primordial mechanisms for regeneration that are active in lower vertebrates such as newts.” The article “Transdifferentiation of Human Fibroblasts to Endothelial Cells: Role of Innate Immunity” by Nazish Sayed, Wing Tak Wong, Frank Ospino, Shu Meng, Jieun Lee, Arshi Jha, Philip Dexheimer, Bruce J. Aronow, and John P. Cooke was published in Circulation, 2014; published online before print 30 October 2014; doi:10.1161/ CIRCULATIONAHA.113.007394.

Scar cells (left, nuclei stained blue) are coaxed into becoming blood vessel cells with a new, smallmolecule and protein therapy. Evidence of the conversion is shown in the second panel (right), where red staining indicates the presence of CD31, a protein made by blood vessel cells. Photo courtesy of Jack Wong, Houston Methodist Research Institute. www.scienceprogress.co.uk

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Slowly the tortoise got its shell Through the careful study of modern and early fossil tortoise, researchers now have a better understanding of how tortoises breathe and the evolutionary processes that helped shape their unique breathing apparatus and tortoise shell. The findings published in Nature Communications help determine when and how the unique breathing apparatus of tortoises evolved. Lead author Dr Tyler Lyson of Wits University’s Evolutionary Studies Institute, the Smithsonian Institution and the Denver Museum of Nature and Science said: “Tortoises have a bizarre body plan and one of the more puzzling aspects to this body plan is the fact that tortoises have locked their ribs up into the iconic tortoise shell.” In most animals, ribs play an important role in breathing. However, tortoises have developed a unique abdominal muscular sling that wraps around their lungs and organs to help them breathe. When and how

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this mechanism evolved has been unknown. “It seemed pretty clear that the tortoise shell and breathing mechanism evolved in tandem, but which happened first?” Lyson asked. By studying the anatomy and thin sections (also known as histology), Lyson and his colleagues have shown that the modern tortoise breathing apparatus was already in place in the earliest fossil tortoise, an animal known as Eunotosaurus africanus. There are some 50 specimen of Eunotosaurus which lived in South Africa 260 million years ago and shares many unique features with modern day tortoises, but lacked a shell. A recognisable tortoise shell does not appear for another 50 million years. The study suggests that early in the evolution of the tortoise body plan a gradual increase in body wall rigidity produced a division of function between the ribs and abdominal respiratory muscles. As the ribs

broadened and stiffened the torso, they became less effective for breathing which caused the abdominal muscles to become specialised for breathing, which in turn freed up the ribs to eventually – approximately 50 million years later – to become fully

integrated into the characteristic tortoise shell. Lyson and his colleagues now plan to investigate reasons why the ribs of early tortoises starting to broaden in the first place.

Canine distemper virus threatens wild tigers Along with the pressures of habitat loss, poaching and depletion of prey species, a new threat to the tiger population in the wild has surfaced in the form of canine distemper virus (CDV). According to a new study from the Wildlife Conservation Society and its partners published in PloS ONE, CDV has the potential to be a significant driver in pushing the animals toward extinction. The authors studied the Amur tiger population in Russia’s Sikhote-Alin Biosphere Zapovednik (SABZ), where tiger numbers declined from 38 individuals to nine in the years 2007 to 2012. In 2009 and 2010, six adult tigers died or disappeared from the reserve, and CDV was confirmed in two dead tigers – leading scientists to believe that CDV likely played a role in the overall decline of the population. Joint investigations of CDV have been an ongoing focus of WCS and Russian scientists at Sikhote-Alin Zapovednik and veterinarians at the regional Primorye Agricultural College since its first appearance in tigers in 2003. The scientists used computer modelling to simulate the effects of CDV infection on isolated tiger populations of various sizes and through a series of transmission scenarios. These included tiger-to-tiger transmission and transmission through predation on CDV-infected domestic dogs and/or infected wild carnivores (such as foxes, raccoon dogs and badgers). High and low-risk scenarios for the model were created based on variation in the prevalence of CDV and the tigers’ contact with sources of exposure. www.scienceprogress.co.uk

Modelling showed that smaller populations of tigers were found to be more vulnerable to extinction by CDV. Populations consisting of 25 individuals were 1.65 times more likely to decline in the next 50 years when CDV was present. The results are profoundly disturbing for global wild tigers given that in most sites where wild tigers persist they are limited to populations of less than 25 adult breeding individuals. CDV infection increased the 50‑year extinction probability of tigers in SABZ as much as 55.8% compared to CDV-free populations of equivalent size. “Tigers face an array of threats throughout their range, from poaching to competition with humans for space and for food. Consequently, many tiger populations have become smaller and more fragmented, making them much more susceptible to diseases such as CDV. While we must continue to focus on the primary threats of poaching and habitat destruction, we now must also be prepared to deal with the

A Siberian Tiger. Photo courtesy of Trisha M Shears. Science news

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appearance of such diseases in the future,” said WCS Russia Program Director Dale Miquelle. The authors say that priorities for future research include identifying the domestic and wild carnivore species that contribute to the CDV reservoir, and those that are the most likely sources of infection for tigers. Tigers are too rare to sustain the virus in the long term, so CDV must rely on more abundant carnivore species to persist in the environment. Understanding the structure

of the CDV reservoir will be a critical first step in identifying measures that might prevent or control future outbreaks. The article “Estimating the potential impact of canine distemper virus on the Amur tiger population ( Panthera tigris altaica ) in Russia,” by Martin Gilbert, Dale G. Miquelle, John M. Goodrich, Richard Reeve, Sarah Cleaveland, Louise Matthews, and Damien O. Joly was published in PloS ONE, 29 October 2014; DOI: 10.1371/journal. pone.0110811.

Landmark study on the evolution of insects published An international team of more than 100 researchers has published the first modern roadmap of insect evolution. Understanding how insects are related uncovers their true ecological, economic, and medical importance. The unprecedented results, which were published in Science, reconstruct the insect “tree of life” and answer longstanding questions about the origins and evolution of the most species rich group of organisms on Earth. “When you imagine a giant map of the evolution of life on Earth, insects are by far the largest part of the picture,” says Dr Michelle Trautwein of the California

Academy of Sciences. “We have not had a very clear picture of how insects evolved – from the origins of metamorphosis to which insects were first to fly. New sequencing technology allowed us to compare huge amounts of genetic data, and for the first time ever, we can fill these knowledge gaps. Science is taking us closer to solving the mysteries of the evolution of life than ever before.” Using a dataset consisting of 144 carefully chosen species, the 1KITE (1,000 Insect Transcriptome Evolution) scientists presented reliable estimates on the dates of origin and relationships of all major insect groups based on the enormous molecular dataset they collected. They show that insects originated at the same time as the earliest terrestrial plants about 480  million years ago. Their analyses suggests that insects and plants shaped the earliest terrestrial ecosystems together, with insects developing wings to fly 400 million years ago, long before any other animal could do so, and at nearly the same time that land plants first grew Insect collection from the English: Museo de Ciencias Naturales de Álava (Torre de Doña Ochanda), Vitoria-Gasteiz, substantially upwards to form forests. Spain. Photo courtesy of Zarateman.

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“Phylogeny forms the foundation for telling us the who, what, when, and why of life,” says Dr Karl Kjer, of Rutgers University. “Many previously intractable questions are now resolved, while many of the “revolutions” brought about by previous analyses of smaller molecular datasets have contained errors that are now being corrected.” “We wanted to promote research on the little-studied genetic diversity of insects,” says Dr Xin Zhou, deputy director at the China National GeneBank, who initiated the project. “For applied research, it will become possible to comparatively analyse metabolic pathways of different insects and use this information to more specifically target pest species or insects that affect our resources. The genomic data we studied (the transcriptome – all of the expressed genes) gives us a very detailed and precise view into the genetic constitution and evolution of the species studied.”

The goal to analyse a gigantic amount of insect genetic information posed a major challenge to 1KITE’s bioinformatics and scientific computing team. “During the planning phase of the project it became clear that the available software would not be able to handle the enormous amount of data,” relates Dr Alexis Stamatakis, group leader at the Heidelberg Institute of Theoretical Studies in Germany. “The development of novel software and algorithms to handle ‘big data’ such as these, is another notable accomplishment of the 1KITE team, and lays a theoretical foundation for future analyses of other very large phylogenomic data sets.” The article, “Phylogenomics resolves the timing and pattern of insect evolution” by Michelle Trautwein, Karl M. Kjer and Xin Zhou was published in Science, 7 November 2014, 763 – 767; doi:10.1126/ science.1257570. For more information see: www.1kite.org

A new cure for periodontitis Scientists in Japan have discovered a new potential treatment for periodontitis. Periodontitis, or severe gum infection, is caused by bacteria residing in the mouth and growing in thin sheets or “biofilms”, commonly known as plaque. Treatment options are limited and, in most cases, unpleasant. A new study, recently published by Shinichi Arakawa and colleagues in Japan, tested the efficacy of a new potential bactericide – ozone nanobubble water, or NBW3 for short – against the two main bacterial species that cause periodontitis. The preliminary results are encouraging: NBW3 is not toxic and is effective in clearing the bacteria, at least in a laboratory setting. The first treatment for periodontitis typically involves a trip to the dentist and a “mechanical debridement”, i.e. physical removal of plaque from the teeth www.scienceprogress.co.uk

via scraping. Following (or during) this process, various antibiotics or antiseptics are administered to reduce the number of bacteria in the mouth. However, both antibiotics and antiseptics have their drawbacks, including allergic reactions in some patients, and development of antibiotic resistance. Ideally, one would use a non-toxic, antiseptic agent that does not induce microbial resistance. Ozone (O3), a variant of the oxygen we breathe in the air (O2), is such an agent. Ozone has strong antimicrobial activity and, importantly, does not induce microbial resistance. Furthermore, aqueous ozone is well-tolerated by cells in the mouth. The main hurdle is that ozonated water is unstable: if not used 5 to 10 minutes after preparation, it loses its efficacy. The co‑authors of this paper developed and patented a procedure to prepare stable Science news

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aqueous ozonated water, NBW3, which retains its oxidation ability for months, as long as it is protected from UV rays. It can be then bottled and used as an antiseptic as needed. Preliminary in vitro results, published in the journal Science and Technology of Advanced Materials, showed that NBW3 can kill the bacteria responsible for periodontitis in 30 seconds, without any significant damage to the cells lining the mouth even after 24 hours of exposure. It

remains to be seen whether these promising in vitro findings will be replicated in the mouth, where saliva will dilute the antiseptic and conditions will be more complex, but NBW3 could indeed be a new and valuable treatment for periodontitis. The whole article can be found at: http://iopscience.iop. org/1468-6996/15/5/055003/ article?fromSearchPage=true Lia Zambetti

From our Twitter feed: @SciProgress Stone age axe found with wood handle - incredibly rare find Archaeologists in Denmark have uncovered a stone-age axe complete with its wooden handle. The axe was found during archaeological surveys ahead of a tunnel project and is thought to be 5,500 years old. https://twitter.com/SciProgress/status/537522821069815808 Bee populations decline as they lose favourite pollinating plants Pollen collected before 1950 was analysed to determine the preferred plants for pollination of 57 wild bee species. The recent decline in the availability of these plants has been mirrored by declines in domestic and wild bee populations. https://twitter.com/SciProgress/status/537234527639191554 New technique allows ultrasound to penetrate bone or metal North Caroline State University researchers have used ‘complementary metamaterials’ to offset the ultrasound distortion caused by bone or metal. https://twitter.com/SciProgress/status/535842103968800769 Local brain “clock” revealed for the first time The site of the local circadian clock responsible for controlling the sleep–wake cycle has been identified. https://twitter.com/SciProgress/status/534411156312444929 Molecules in a fluid not randomly arranged Research has demonstrated local ordering of molecules in alcohol, confirming previous computer simulations. Neighbouring O – H bonds in alcohol were discovered to be at an angle of approximately 120° relative to each other. https://twitter.com/SciProgress/status/532861739692326912 Swedish scientists develop renewable, recyclable battery Batteries using renewable organic components such as alfalfa and pine resin could be recycled with low-energy input and non-hazardous chemicals. https://twitter.com/SciProgress/status/523040332179861504 406
