Category: Environment

{Sneaky parasitic weeds may be able to steal genes from the plants they are attacking and then use those genes against the host plant, according to a team of scientists.}

In a study, researchers detected 52 incidents of the nonsexual transfer of DNA — known as horizontal gene transfer, or HGT — from a host plant that later became functional into members of a parasitic plant family known as the broomrapes, said Claude dePamphilis, professor of biology, Penn State. The transferred genes then became functional in the parasitic species. Although considered rare in more plants and other complex species, like plants, HGT may thus occur in some parasitic plants, an insight that could lead to better methods of controlling parasitic plants that threaten agriculture, he added.

“These parasitic plants that we study from the broomrape family include some of the the world’s most devastating agricultural weeds,” said dePamphilis. “The HGT discovery is really part of our effort to try to better understand how parasitic plants work and how we can better control them. Our hope is that we can use this information to find the best strategies to generate, or breed, resistant host plants.”

The researchers, who released their findings in the current issue of Proceedings of the National Academy of Sciences, suggest that the transfer could boost the parasitic plant’s ability to invade their hosts and overcome defenses the host creates to try to ward off attacks. HGT may also help reduce the risk of infection for the parasites.

While horizontal gene transfers in less complex species, such as bacteria, is are common, most evolution in more complex organisms is driven by the sexual exchange of DNA, along with mutation and natural selection. However, the researchers suggest that the close feeding connections of parasitic plants with their hosts may increase the chances of intact genes traveling from the host to the parasite’s genome where it can quickly become functional.

“Parasitic plants seem to have a far greater rate of horizontal gene transfer than non-parasitic plants and we think this is because of their very intimate connection they have with their host,” said dePamphilis.

The roots of the parasite contact and enter the host, and then begin extracting water, sugars, mineral nutrients and even nucleic acids, including DNA and RNA, he added.

“So, they are stealing genes from their host plants, incorporating them into the genome and then turning those genes back around, very often, as a weapon against the host,” said dePamphilis.

Farmers throughout the world struggle with these types of parasitic plants, which are so numerous in some areas of the world that they become a major source of crop loss. In Sub-Saharan Africa, for example, Striga — or witchweed — is one of the most damaging sources of agricultural loss, according to dePamphilis.

To detect HGT in the plants, the researchers used data generated by their collaborative research effort funded by the U.S. National Science Foundation — the Parasitic Plant Genome Project — to generate evolutionary histories for thousands of genes in the parasitic plants, said dePamphilis.

The researchers focused on transcriptomes — expressed gene sequences — of three parasitic plants:, Triphysaria versicolor, also called yellowbeak owl’s-clover; Striga hermonthica, or giant witchweed; and Phelipanche aegyptiaca, called Egyptian broomrape, as well as the nonparasitic plant Lindenbergia philippensis, and genome sequences from 22 other nonparasitic plants. Because the researchers considered mRNA, which can move between hosts and their parasites, as a possible source of the transfers, they tested and re-tested the data to rule out the experimental host as the source of the genetic material. Instead, they found that the foreign sequences had been derived from entire genes of past host plants and incorporated into the parasitic plants genomes.

Future research may investigate the mechanism of horizontal gene transfer to help engineer improved plant defenses against parasitic attacks, dePamphilis said.

{Last week, nearly 200 countries found a compromise that will phase out super-polluting HFC gases. Some say the US Senate could slow that progress, but many observers say that the United States – and the world – is on the right track.}

The Kigali agreement to phase out a particularly potent greenhouse gas is a big deal for climate protection efforts and international cooperation more broadly.

The agreement commits almost 200 countries to reducing their use of hydrofluorocarbons (HFCs) over the next 30 years. These compounds – most often used in refrigerators and air conditioners – are the world’s fastest-growing greenhouse gases. The international community agreed that cutting the artificial pollutants, which have a warming effect 1,600 times more powerful than carbon dioxide on average, would be a straightforward step toward meeting the Paris Agreement goal to keep global temperatures from rising more than 2 degrees Celsius above preindustrial levels.

Now, with the meetings in Kigali concluded, attention has turned to implementation. One possible obstacle to curbing HFC use: the US Senate. If the Senate is required to approve the phase-out, some say they would refuse, perhaps leading other countries to question their commitments too. But others say the United States is fully committed to implementing the agreement, while technological transformation makes phasing out the gases less of a burden for developing countries.

That countries are willing to enter into a legally binding agreement about HFCs signals the depth of their commitment to addressing climate change issues. And its success could pave the way for further progress, observers say.

“This is the biggest step that could be taken and now has been taken in the year following the Paris Agreement. It really continues … the international momentum,” David Doniger, director of the Climate and Clean Air Program at the Natural Resources Defense Council, tells The Christian Science Monitor. “It’s an important statement that the level of cooperation is high. We’re in a virtuous circle — countries saying, ‘I will if you will,’ ” he continues.

Mr. Doniger sees the United States at the forefront of this positive international movement. He points out that the United States was one of those pushing the hardest for some kind of agreement on HFCs. “I have no doubt that the United States will become a party to Kigali,” he underlines.

For Steve Seidel, senior advisor at the Center for Climate and Energy Solutions, US support for the Kigali Agreement is borne out in the actions the country is already taking to reduce its use of HFCs.

“We’ve already seen alternatives developed in all the major use categories,” including refrigerators and air conditioners, he says in a phone interview with the Monitor. Often, these alternatives are not only better for the environment but more efficient. As a result, “the HFC amendment has brought very broad support from industry and the environmental community,” he says.

It is unclear whether the Senate will be asked to review the Kigali Agreement. “We will need to examine the content and the form of the agreed amendment, as well as relevant practice, in order to determine the appropriate approval process,” Emily White, a spokeswoman for the State Department, told Climate Central on Monday.

Nigel Purvis, chief executive officer of Climate Advisers and a former State Department treaty lawyer, says that such approval may not be necessary.

“It’s a well established principle of U.S. law that the President can approve, without further Congressional review, certain international agreements that fall under a treaty already approved by the Senate,” he wrote in an emailed statement to the Monitor. The Montréal Protocol, to which the Kigali Agreement is an amendment, was overwhelmingly approved by the Senate in 1988, with a vote of 83 to 0.

“Our Senate is always a challenge in ratifying environmental treaties these days,” Mr. Seidel says, though he notes that the Senate has a long history of ratifying similar amendments. And politicians on both sides of the aisle have increasingly shown themselves open to cooperation on climate issues. Last year, four Republican senators formed a working group to discuss environmental protection and clean energy initiatives. A group of Democratic and Independent senators signed a letter calling for strong action on HFCs in Kigali.

With or without Senate approval, both Doniger and Seidel believe progress to phase down HFCs will continue. Doniger says the international community has experience of phasing out any number of chemicals, and will be able to do so again. In the process, countries will get technical support from the World Bank, the UN Development Program, and the UN Environment Program. Financial assistance will come from the Montréal Protocol’s Multilateral Fund, which helps developing countries cover the cost of phasing out chemicals.

Seidel explains that technological change to support the drawdown in HFCs is already happening in developing countries like China and India. The amendment “builds on market forces that are beginning to take hold.” This, coupled with the pressure developing states say they are feeling from climate change, means ratification may be more of a formality on the way to eliminating HFC gases.

“The process is underway and will continue regardless of when ratification and entry into force occurs,” Seidel says.

{Teeth striations of Homo habilis fossil date back 1.8 million years.}

Perhaps the bias against left-handers dates back much further than we thought.

By examining striations on teeth of a Homo habilis fossil, a new discovery led by a University of Kansas researcher has found the earliest evidence for right-handedness in the fossil record dating back 1.8 million years.

“We think that tells us something further about lateralization of the brain,” said David Frayer, a KU professor emeritus of anthropology and the lead author of the study. “We already know that Homo habilis had brain lateralization and was more like us than like apes. This extends it to handedness, which is key.”

The findings were published online this week in the Journal of Human Evolution. The researchers made the discovery after analyzing small cut marks, or labial striations, which are the lip side of the anterior teeth in an intact upper jaw fossil, known as OH-65, found in a stream channel of the Olduvai Gorge in Tanzania.

Frayer said among the network of deep striations found only on the lip face of the upper front teeth most cut marks veered from left down to the right. Analysis of the marks makes it likely they came from when OH-65 used a tool with its right hand to cut food it was holding in its mouth while pulling with the left hand. The scratches can be seen with the naked eye, but a microscope was used to determine their alignment and to quantify their angulation.

“Experimental work has shown these scratches were most likely produced when a stone tool was used to process material gripped between the anterior teeth and the tool occasionally struck the labial face leaving a permanent mark on the tooth’s surface,” Frayer said.

Based on the direction of the marks, it’s evident the Homo habilis was right-handed. It’s a sample of one, but because this is the first potential evidence of a dominant handed pre-Neanderthal, Frayer said, the study could lead to a search for the marks in other early Homo fossils.

“Handedness and language are controlled by different genetic systems, but there is a weak relationship between the two because both functions originate on the left side of the brain,” he said. “One specimen does not make an incontrovertible case, but as more research is done and more discoveries are made, we predict that right-handedness, cortical reorganization and language capacity will be shown to be important components in the origin of our genus.”

Multiple lines of research point to the likelihood that brain reorganization, the use of tools and use of a dominant hand occurred early in the human lineage. Today, researchers estimate that 90 percent of humans are right-handed, and this differs from apes which are closer to a 50-50 ratio. Until now, no one looked for directionality of striations in the earliest specimens representing our evolutionary lineage.

“We think we have the evidence for brain lateralization, handedness and possibly language, so maybe it all fits together in one picture,” Frayer said.

{Wild-bearded capuchin monkeys in Brazil deliberately break stones, unintentionally creating flakes that share many of the characteristics of those produced by early Stone Age hominins.}

Researchers have observed wild-bearded capuchin monkeys in Brazil deliberately break stones, unintentionally creating flakes that share many of the characteristics of those produced by early Stone Age hominins. The difference is that the capuchins’ flakes are not intentional tools for cutting and scraping, but seem to be the by-product of hammering or ‘percussive behaviour’ that the monkeys engage in to extract minerals or lichen from the stones.

In a paper, published in Nature, the research team says this finding is significant because archaeologists had always understood that the production of multiple stone flakes with characteristics such as conchoidal fractures and sharp cutting edges was a behaviour unique to hominins. The paper suggests that scholars may have to refine their criteria for identifying intentionally produced early stone flakes made by hominins, given capuchins have been observed unintentionally making similar tools.

The research is authored by researchers from the University of Oxford, University College London and University of São Paulo in Brazil. The team observed individual monkeys in Serra da Capivara National Park unintentionally creating fractured flakes and cores. While hominins made stone flake tools for cutting and butchery tasks, the researchers admit that it is unclear why monkeys perform this behaviour. They suggest that the capuchins may be trying to extract powdered silicon (known to be an essential trace nutrient) or to remove lichen for some as yet unknown medicinal purpose. At no point did the monkeys try to cut or scrape using the flakes, says the study.

Lead author Dr Tomos Proffitt, from the School of Archaeology at the University of Oxford, comments: ‘Within the last decade, studies have shown that the use and intentional production of sharp-edged flakes are not necessarily linked to early humans (the genus Homo) who are our direct relatives, but instead were used and produced by a wider range of hominins. However, this study goes one step further in showing that modern primates can produce archaeologically identifiable flakes and cores with features that we thought were unique to hominins.

‘This does not mean that the earliest archaeological material in East Africa was not made by hominins. It does, however, raise interesting questions about the possible ways this stone tool technology developed before the earliest examples in the archaeological record appeared. It also tells us what this stone tool technology might look like. There are important questions too about the uniqueness of early hominin behaviour. These findings challenge previous ideas about the minimum level of cognitive and morphological complexity required to produce numerous conchoidal flakes.’

The monkeys were observed engaging in ‘stone on stone percussion’, whereby they individually selected rounded quartzite cobbles and then using one or two hands struck the ‘hammer-stone’ forcefully and repeatedly on quartzite cobbles embedded in a cliff face. This action crushed the surface and dislodged cobbled stones, and the hand-held ‘hammer stones’ became unintentionally fractured, leaving an identifiable primate archaeological record. As well as using the active hammer-stone to crush ‘passive hammers’ (stones embedded in the outcrop), the capuchins were also observed re-using broken hammer-stones as ‘fresh’ hammers.

The research team examined 111 fragmented stones collected from the ground immediately after the capuchins had dropped them, as well as from the surface and excavated areas in the site. They gathered complete and broken hammer-stones, complete and fragmented flakes and passive hammers. Around half of the fractured flakes exhibited conchoidal fracture, which is typically associated with the hominin production of flakes.

Bearded capuchins and some Japanese macaques are known to pound stones directly against each other, but the paper remarks that the capuchins in Serra da Capivara National Park are the only wild primates to be observed doing this for the purpose of damaging the stones.

Co-author and leader of the Primate Archaeology (Primarch) project Michael Haslam, from the University of Oxford, says: ‘Our understanding of the new technologies adopted by our early ancestors helps shape our view of human evolution. The emergence of sharp-edged stone tools that were fashioned and hammered to create a cutting tool was a big part of that story. The fact that we have discovered monkeys can produce the same result does throw a bit of a spanner in the works in our thinking on evolutionary behaviour and how we attribute such artefacts. While humans are not unique in making this technology, the manner in which they used them is still very different to what the monkeys seem capable of.’

{Ancient DNA research has revealed that Ice Age cave artists recorded a previously unknown hybrid species of bison and cattle in great detail on cave walls more than 15,000 years ago.}

The mystery species, known affectionately by the researchers as the Higgs Bison* because of its elusive nature, originated over 120,000 years ago through the hybridisation of the extinct Aurochs (the ancestor of modern cattle) and the Ice Age Steppe Bison, which ranged across the cold grasslands from Europe to Mexico.

Research led by the Australian Centre for Ancient DNA (ACAD) at the University of Adelaide, published today in Nature Communications, has revealed that the mystery hybrid species eventually became the ancestor of the modern European bison, or wisent, which survives in protected reserves such as the Białowieża forest between Poland and Belarus.

“Finding that a hybridisation event led to a completely new species was a real surprise — as this isn’t really meant to happen in mammals,” says study leader Professor Alan Cooper, ACAD Director. “The genetic signals from the ancient bison bones were very odd, but we weren’t quite sure a species really existed — so we referred to it as the Higgs Bison.”

The international team of researchers also included the University of California, Santa Cruz (UCSC), Polish bison conservation researchers, and palaeontologists across Europe and Russia. They studied ancient DNA extracted from radiocarbon-dated bones and teeth found in caves across Europe, the Urals, and the Caucasus to trace the genetic history of the populations.

They found a distinctive genetic signal from many fossil bison bones, which was quite different from the European bison or any other known species.

Radiocarbon dating showed that the mystery species dominated the European record for thousands of years at several points, but alternated over time with the Steppe bison, which had previously been considered the only bison species present in Late Ice Age Europe.

“The dated bones revealed that our new species and the Steppe Bison swapped dominance in Europe several times, in concert with major environmental changes caused by climate change,” says lead author Dr Julien Soubrier, from the University of Adelaide. “When we asked, French cave researchers told us that there were indeed two distinct forms of bison art in Ice Age caves, and it turns out their ages match those of the different species. We’d never have guessed the cave artists had helpfully painted pictures of both species for us.”

The cave paintings depict bison with either long horns and large forequarters (more like the American bison, which is descended from the Steppe bison) or with shorter horns and small humps, more similar to modern European bison.

“Once formed, the new hybrid species seems to have successfully carved out a niche on the landscape, and kept to itself genetically,” says Professor Cooper. “It dominated during colder tundra-like periods, without warm summers, and was the largest European species to survive the megafaunal extinctions. However, the modern European bison looks genetically quite different as it went through a genetic bottleneck of only 12 individuals in the 1920s, when it almost became extinct. That’s why the ancient form looked so much like a new species.”

Professor Beth Shapiro, UCSC, first detected the mystery bison as part of her PhD research with Professor Cooper at the University of Oxford in 2001. “Fifteen years later it’s great to finally get to the full story out. It’s certainly been a long road, with a surprising number of twists,” Professor Shapiro says.

*The Higgs Boson is a subatomic particle suspected to exist since the 1960s and only confirmed in 2012.

{An extensive study led by a researcher at Lund University in Sweden has mapped the effects of small farmers on the rain forests of Southeast Asia for the first time. The findings are discouraging, with regard to environmental impact, biodiversity and the economy, over the long term.}

Until now, studies of this kind have always focused largely on large-scale palm oil producers and how they exploit the forest and soil. Now Yann Clough, a researcher at the Faculty of Science at Lund University, has mapped the choice of trees and agricultural methods of small-scale Indonesian farmers. Together with over 40 researchers from Germany, Indonesia, Switzerland and New Zealand, he has assessed the biodiversity and ecosystem functions in natural forest, in traditional agroforests and in monocultures of palm oil and rubber trees; the data measured includes amongst others forest growth, soil fertility and carbon storage. Furthermore, the team interviewed 450 small scale farmers to better understand why they chose to cultivate only oil palms or rubber trees and how this affects their economy.

“For the great majority of small farmers, chopping down diverse forests and investing in a single species of tree — monoculture — is the simplest and quickest path out of poverty. Productivity increases, the financial risk drops and income rises,” says Yann Clough.

However, the short-term financial gain is the only benefit of monoculture, according to the study. Biodiversity declines dramatically, the forest loses significance as a carbon source and the increased use of mineral fertiliser leads to additional leaching of nutrients such as nitrogen. Even though the study focused on Indonesia, there are equivalent problems in many other parts of the world.

The study and its results contradict the traditional view that small scale agriculture is environmentally friendly. Collectively, small farmers cultivate a larger part of Indonesia’s forests than that exploited by large landowners. When the small farmers largely embrace monoculture as an agricultural system, they put a great deal of strain on the environment and on biodiversity. Changing the agricultural methods of small farmers requires efforts from various sides and must comprise financial support in order for the farmers to change their way of producing, according to the researchers.

“Since the small farmers earn more with monoculture, sustainability aspects and the effects on nature currently are almost entirely unheeded. Changing the production methods of small farmers requires financial incentives along with political will; otherwise there is a risk that rich and productive agricultural land will have disappeared altogether in 20 years,” says Yann Clough.

The study is presented in an article in the online scientific journal Nature Communications.

{Study of social rank in wild chimps shows striking differences between the sexes.}

For wild chimpanzees, social status is more than just a matter of pride. High-ranking chimpanzees of both sexes usually have better access to food and mates, boosting chances of survival for themselves and their offspring.

But male and female chimpanzees achieve social status in dramatically different ways, says a new study by primatologists at Duke University. While males actively challenge their superiors to win higher rank, females accept their position in the social pecking order, waiting until more senior group members die before moving up the ladder.

The study, which appeared online Oct. 14 in the journal Scientific Reports, provides the first detailed look at how social status among wild chimpanzees changes throughout their lifetimes.

“We found that, after entering the adult hierarchy, there was a complete absence of successful challenges for rank increases among females,” said Steffen Foerster, senior research scientist at Duke University and lead author on the study. “It’s like a formal queue.”

Unlike the more gregarious males, female chimpanzees tend to be loners, spending much time by themselves or with their own children. One-on-one encounters between females are generally rare, giving researchers few opportunities to observe signs that would clue them in to each chimpanzee’s relative rank.

“For a long time we’ve been aware that there really are differences in rank between females, but being able to quantify that has been hard because they really don’t interact very often,” said Duke evolutionary anthropology professor Anne Pusey, who is a senior author on the paper.

To explore how female chimpanzees maneuver up and down the social ladder, Foerster, Pusey and their colleagues plumbed more than 40 years of daily records documenting the behaviors of 100 or so wild chimpanzees residing in Gombe National Park in Tanzania, where Pusey first began working alongside Jane Goodall in 1970.

Chimpanzees signal dominance and submission to each other through acts of aggression, such as chases and attacks, and through making a sound called a “pant-grunt,” which is a clear sign of subordination to a superior. The team used a new rating system to document these interactions, allowing them to determine the rank orders of male and female chimpanzees and watch how they shifted over time.

Their results showed that, unlike males, whose rank usually peaks when they reach their prime in their early 20s before declining again, female rank gradually increases as they age, and their rank order remains stable throughout their lifetimes. In addition, though males almost always start their adulthoods at the bottom of the pecking order, the female starting rank varies with each individual.

“That seems to be a crucial moment for them, because after they enter the hierarchy at about 12 years of age, they can’t really change anything about their position unless something happens at the top and individuals die,” Foerster said.

The team is still investigating how these initial rankings are established, but preliminary evidence indicates that females with mothers in the group seem to have an edge.

Despite the benefits of social status on their reproductive success — higher-ranking females appear to have access to better food and higher infant survival than their low-ranking counterparts — the tendency of female chimpanzees to “wait their turn” rather than fighting for rank reveals the competing priorities males and females face when ensuring the success of their offspring.

“If a male has a high rank even for a short time but manages to fertilize a lot of females, he achieves high reproductive success,” Pusey said. “Whereas a female is only able to raise one offspring at a time, so her reproductive success depends largely on how long she lives.”

Compared to males, female chimpanzees “likely have to consider a long-term strategy,” Foerster said. “It is potentially dangerous to challenge each other — you may get injured, your offspring may be killed if you have a little baby. Finding that females actually do not fight for rank tells us how costly these challenges must be for them.”

For female chimpanzees, good things come to those who wait.

{Researchers from the Universitat Autònoma de Barcelona (UAB) in collaboration with the Institut Català de Paleontologia Miquel Crusafont (ICP), have discovered in Vallcebre (Barcelona) an impression fossil with the surface of the skin of a dinosaur from the Late Cretaceous, a period right before their extinction. Its characteristics make it a unique discovery in Europe.
}
A geological research conducted in the village of Vallcebre, near Barcelona, to study the origins of rock sediments from the Late Cretaceous period (approx. 66 million years ago) has revealed an extraordinary artefact. Researchers discovered the impression of skin scales left by a dinosaur which had lain down in the mud. During that period, the area was a muddy region corresponding to the banks of a river. As chance had it, that muddy region where the animal’s scales had left their mark was later covered with sand which, in the course of thousands of years, finally petrified to form sandstone and thus become the sedimentary rock which preserves the impression recently discovered by the researchers. The sand acted as a mould and therefore, what actually can be seen on the rock is not really the impression, but the relief of the animal’s original skin.

The characteristics of the discovery are unique, given that the Late Cretaceous period corresponds to the moment short before dinosaurs became extinct, there are few places on Earth containing sandstone from this period, and characterising these dinosaurs is very important in order to understand how and why they disappeared. “This is the only registry of dinosaur skin from this period in all of Europe, and it corresponds to one of the most recent specimens, closer to the extinction event, in all of the world,” highlights UAB researcher Victor Fondevilla, main author of the research. “There are very few samples of fossilised skin registered, and the only sites with similar characteristics can be found in United States and Asia,” Fondevilla states. He goes on to say: “Other dinosaur skin fossils have been found in the Iberian Peninsula, in Portugal and Asturias, but they correspond to other more distant periods.”

The shape of the scales observed on the rock show a pattern characteristic of the skin of some dinosaurs: in a form of a rose with a central bump in the shape of a polygon, surrounded by five or six more bumps. However, the scales are large, too large for the typical size of carnivorous dinosaurs and hadrosaurs roaming this area 66 million years ago. “The fossil probably belongs to a large herbivore sauropod, maybe a titanosaurus, since we discovered footprints from the same species very close to the rock with the skin fossil” Fondevilla says.

In fact, two skin impressions were found, one measuring approximately 20 centimetres wide, and the other slightly smaller, measuring only 5 centimetres wide, separated by a 1.5 metre distance and probably made by the same animal. “The fact that they are impression fossils is evidence that the animal is from the sedimentary rock period, one of the last dinosaurs to live on the planet. When bones are discovered, dating is more complicated because they could have moved from the original sediment during all these millions of years,” Fondevilla states.

The finding verifies the excellent fossil registry of the Pyrenees in terms of dinosaurs living in Europe little before they became extinct throughout the planet. “The sites in Berguedà, Pallars Jussà, Alt Urgell and La Noguera, in Catalonia, have provided proof of five different groups of dinosaurs: titanosaurs, ankylosaurids, theropods, hadrosaurs and rhabdodontids,” explains Àngel Galobart, head of the Mesozoic research group at the ICP and director of the Museum of Conca Dellà in Isona. “The sites in the Pyrenees are very relevant from a scientific point of view, since they allow us to study the cause of their extinction in a geographic point far away from the impact of the meteorite,” Galobart explains.

The research, published in Geological Magazine, was led by Víctor Fondevilla and Oriol Oms from the UAB Department of Geology, in collaboration with Bernat Vila and Àngel Galobart, both from the Institut Català de Paleontologia Miquel Crusafont (ICP) and the Museum of Conca Dellà.

{An international research team has developed an effective treatment strategy against the HIV-like Simian Immunodeficiency Virus (SIV) in rhesus macaques.}

According to the WHO, around 36 million people are infected with HIV and a cure for the deadly virus infection has not yet been found. An international research team that includes scientists from the German Primate Center (DPZ), Leibniz Institute for Primate Research in Göttingen, has developed a new treatment strategy against the HIV-related Simian Immunodeficiency Virus (SIV). SI viruses infect different primate species and are regarded as the origin of the Human Immunodeficiency Virus. In the study, SIV-infected rhesus macaques were treated with an antiretroviral drug for 90 days and in addition they were treated with a specific antibody for 23 weeks. After finishing this therapy, all macaques showed sustained control of the infection as almost no SI viruses could be detected in the blood and gastro-intestinal tissues. The CD4+ T cells that are essential for the immune system were present in sufficient numbers in these tissues. Two years after finishing the treatment the viral load remained low, the immune system intact, and the rhesus macaques healthy. The treatment strategy thus offers a new and promising approach to the therapy of HIV infections in humans (Science).

Antiretroviral therapy is currently the most frequently used treatment of HIV infections. The drugs effectively block the proliferation of the HI viruses in the infected cells and thus delay the onset of the disease. However, these drugs have to be administered permanently since their discontinuation would immediately lead to virus rebound in the body. Their continuous administration is accompanied by adverse effects such as chronic inflammation, poisoning symptoms and accelerated aging. “The aim of the study was to find a new therapeutic approach for the treatment of infections with immunodeficiency viruses, which would permanently prevent the proliferation of the viruses even after only temporarily application,” says Lutz Walter, head of the Primate Genetics Laboratory at the DPZ and co-author of the publication.

The study was conducted in the US under the leadership of scientists from the Emory University School of Medicine in Atlanta and the National Institutes of Health (NIH), Bethesda, USA. From the fifth to the 18th week after infection, the rhesus macaques received an antiretroviral drug identical to the ones given to humans. From the ninth week, this treatment was combined with a specific antibody therapy, which was repeated at regular intervals of three weeks. A control group received only antiretroviral therapy and an irrelevant control antibody. After the 18th week the antiretroviral therapy was terminated and only the antibody was administered until the 32nd week, whereupon the treatment of the monkeys was halted. “It is known that the SI and HI viruses tend to multiply especially in CD4+ T cells of the intestinal mucosa and thereby establish a chronic infection,” explains Lutz Walter. “The specific antibody prevents the entry of these immune cells into the mucosa. A further spread of the viruses was thereby effectively stopped and the rhesus macaques have controlled the virus infection since almost two years without further medication.” After the treatment has ended, the viral load and the amount of CD4+ T cells in the animals were determined. In the blood and intestinal tissue, the virus load was below the detection threshold and the CD4+ T cells count were stable, indicating a functional immune system.

In addition to Lutz Walter, the other DPZ participants in the study were Christian Roos and Angela Noll. The three primate genetics experts investigated certain genetic markers of rhesus macaques. The focus was on the MHC class I genes as well as the genes of the killer cell immunoglobulin-like receptors (KIR). Both gene families are essential for a functional immune system as well as for the immunological identity of an organism. “Since certain variants of these genes are known to be beneficial or detrimental in the SIV infection, we have determined the alleles of these genes in all macaques of this study,” says Lutz Walter. “We wanted to make sure that the monkeys of the control and antibody-treated group just by chance do not have unfavorable and favorable alleles, respectively.” This partial result is important to secure the outcome of the study.

The antibody that was used to treat the macaques is a primatized variant of the therapeutic monoclonal antibody that is known as Vedolizumab and has been available since 2014 in the USA and in Europe. It is administered to patients to treat chronic inflammatory bowels diseases such as Crohn’s disease and ulcerative colitis where the CD4+ T cells also play an important role. The scientists are seeking to test the new treatment strategy in clinical trials with HIV patients. A phase-I clinical trial is already underway in the United States. The aim is to find out whether a combination of antiretroviral therapy with Vedolizumab has the same effect in humans. “We have good reasons to believe that the therapy will work similarly in humans,” says Lutz Walter. “It would be a breakthrough for the future treatment of HIV patients.”

In addition to the scientists of the Emory University School of Medicine, the National Institutes of Health (NIH) and the DPZ, researchers of the Center for the AIDS Program of Research in South Africa, the Georgia Institute of Technology College of Engineering, the John Hopkins School of Medicine, the University of Maryland School of Pharmacy, and the University of Michigan were involved in the project.

{The oldest known vocal organ of a bird has been found in an Antarctic fossil of a relative of ducks and geese that lived more than 66 million years ago during the age of dinosaurs.}

The discovery of the Mesazoic-era vocal organ — called a syrinx — and its apparent absence in nonavian dinosaur fossils of the same age indicate that the organ may be have originated late in the evolution of birds and that other dinosaurs may not have been able to make noises similar to the bird calls we hear today, according to findings published in Nature on Oct 12. Birds are direct descendants of dinosaurs and are considered living dinosaurs by scientists.

“This finding helps explain why no such organ has been preserved in a nonbird dinosaur or crocodile relative,” said Julia Clarke, a paleontologist at The University of Texas at Austin Jackson School of Geosciences who discovered the fossil syrinx and led the analysis. “This is another important step to figuring out what dinosaurs sounded like as well as giving us insight into the evolution of birds.”

The syrinx is made of stiff, cartilage rings that support soft tissues that vibrate to produce the complex songs and calls of modern birds. Cartilage does not fossilize as well as hard tissues such as bone. But the high mineral content in the syrinx’s rings sometimes allows for fossilization. All other known examples of fossilized syrinxes occur in birds that lived well after nonavian dinosaurs went extinct.

The syrinx was found in a fossil of Vegavis iaai, a bird that lived during the Cretaceous. Clarke described the species in 2005. It was discovered on Antarctica’s Vega Island in 1992 by a team from the Argentine Antarctic Institute. However, it wasn’t until 2013 that Clarke noticed that the Vegavis fossil included a syrinx. During the past two years, the team searched the dinosaur fossil record for other examples of a syrinx, but so far has found none.

The asymmetrical shape of the syrinx indicates that the extinct species could have made honking noises via two sound sources in the right and left parts of the organ. The researchers also scanned syrinxes of other birds to compare with the Vegavis syrinx. This included 12 syrinxes from living birds and the next oldest fossilized syrinx, which had not yet been studied.

Franz Goller, a co-author and physiologist at the University of Utah, said the study is the beginning of the work to determine what the fossilized organ can tell us about the sounds of early birds.

“Here, we begin to outline how fossilizable characteristics of the syrinx may inform us about sound features, but we need a lot more data on living birds,” Goller said. “Remarkably, prior to this work, there is almost no discussion of these important questions.”

This study follows research that Clarke and other collaborators published in July 2016 that found some dinosaurs would likely have made closed-mouth vocalizations akin to ostrich booms that don’t require a syrinx. Together, the two studies have major implications for dinosaur sound-making throughout time, Clarke said.

In addition, the evolution of vocal behavior can give insights into other anatomical features, Clarke said, such as the appearance of bigger brains.

“The origin of birds is about so much more than the evolution of flight and feathers,” Clarke said.

To study sound production in more detail, part of the team is working with engineers to model sound-producing organs, a project funded by the Gordon and Betty Moore Foundation.