Oil Dispute Takes a Page From Congo’s Bloody Past

Primates indispensable for regeneration of tropical forests

Primatologist and plant geneticists have studied the dispersal of tree seeds by New World primates.

Primates can influence seed dispersal and spatial genetic kinship structure of plants that serve as their food source. This is the result of a cooperation project of behavioral ecologist Eckhard W. Heymann from the German Primate Center (DPZ) with plant geneticists Birgit Ziegenhagen and Ronald Bialozyt from the Philipps-University Marburg. This study was funded by the German Research Foundation.

At the DPZ-field station Estación Biológica Quebrada Blanco in the Peruvian Amazonian lowlands, scientists studied how feeding, sleeping, and ranging habits of two species of New World monkeys affect the dispersal of the neotropical legume tree Parkia panurensis. For this, the researchers observed a group of Brown-mantled tamarins (Saguinus nigrifrons) and Moustached tamarins (Saguinus mystax), who jointly moved through home ranges in search of edible plants which included Parkia trees.

Fruits from these trees are pods that contain 16 to 23 seeds, each of which is surrounded by edible gum. The monkeys feed on the gum content of the pods and at the same time swallow the Parkia seeds which are later defecated intact in a different area.

During behavioral observations, researchers recorded the food intake of tamarins as well as the location of the Parkia trees that they visited. In addition, they collected faecal samples of the tamarins that contained seeds. “With the help of genetic analyses of the DNA found in the seed coat, which is of maternal origin, we could make an exact assignment of the corresponding “mother tree” for the seeds,” says Eckhard W. Heymann from the DPZ. “This allowed us to determine how far Parkia seeds were dispersed by the monkeys.”

In order to analyze the effect of seed dispersal by monkeys on a spatial genetic level, the scientists examined three different developmental stages of the trees. In addition to the seeds that contain the plant embryo, they collected leaves from young and mature Parkia trees in the home range of tamarins. “With the help of analysis from microsatellites, short repeated DNA sequences, we were able to identify genetic similarities of individual trees,” says Heymann.

The analysis of the spatial genetic structure of the Parkia population revealed a significant genetic relationship of the plant embryos and young trees within a radius of 300 meters, which coincides with the distance within which most seeds are dispersed by the tamarins. For mature trees, the relationship was reduced to a radius of only up to 100 meters.

“In tropical rain forests, the seeds of 80 to 90 percent of trees and lianas are dispersed by animals. In addition to primates, birds and bats are the major animal groups that are responsible for seed dispersal,” says behavioral ecologist Heymann. “For the plants, transport of their seeds is extremely important. As sedentary organisms, this is the only way that their offspring — the embryos contained in the seeds — can reach appropriate sites for germination and growth. Furthermore, this reduces the density-dependent mortality which occurs when the seeds fall under the mother plants,” says Eckhard W. Heymann. Fruit-eating primates such as tamarins are therefore invaluable to the natural regeneration and diversity of ecosystems in which they live.

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Oil Dispute Takes a Page From Congo’s Bloody Past

Oil Dispute Takes a Page From Congo’s Bloody Past

Monkeys Steer Wheelchairs With Their Brains, Raising Hope for Paralyzed People

Brain-machine interfaces have become a buzzword in recent years, triggering headlines when, for example, Brown University’s John Donoghue’s human patients drank coffee and picked up objects with robotic arms controlled by brain-implanted electrodes.

At the meeting, Nicolelis also presented research on two rhesus monkeys that had electrodes implanted deep in their brains that, with training, allowed the animals to steer a wheelchair using thought alone. The goal of that research is partly to help develop a “brain pacemaker” implant that would pick up clearer signals from thoughts to help control future robotic prosthetics.

Signals from deep in the brain are much easier for devices to read than ones picked up by electrical skin sensors on patient’s skulls. Such implants made the monkeys relatively quick students at wheelchair driving. “They can reliably steer the wheelchair to get a grape,” Nicolelis said. “They like grapes.”

Full story here .

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Oil Dispute Takes a Page From Congo’s Bloody Past

Females protect offspring from infanticide by forcing males to compete through sperm

Previous research has shown that infanticide by males is widespread in many mammal species, but most commonly occurs in those species where females live in social groups dominated by one or a few males.

Outsiders will fight dominant males for access to the females. When a rival male takes over a group, they will kill the infants of previously dominant males to render the females ‘sexually receptive’ again, so that they can sire their own offspring. This may be the main cause of infant mortality in some species, such as Chacma baboons.

Now, a new study published today in the journal Science shows that these brutal acts are strategic; males may only have a short time in charge before they themselves are deposed, and want to ensure the maternal investment of females is directed towards their own future offspring for the longest time possible.

However, the females of some species — such as the mouse lemur — have evolved a highly-effective counter-strategy to stop males from killing their offspring: by having as many mates as possible in a short amount of time. By confusing the paternity of the infants, known as ‘paternity dilution’, any male act of infanticide risks the possibility of killing his own offspring.

In such species, reproductive competition shifts to after copulation, not before — so that the most successful male is the one whose sperm outcompetes those of the others. This leads to males producing ever larger quantities of sperm, leading in turn to increases in testis size. The testes of male mouse lemurs swell 5-10 times larger during the breeding season.

“In species in which infanticide occurs, testis size increases over generations, suggesting that females are more and more promiscuous to confuse paternity,” said lead author Dr Dieter Lukas, from University of Cambridge’s Department of Zoology.

“Once sperm competition has become so intense that no male can be certain of his own paternity, infanticide disappears — since males face the risk of killing their own offspring, and might not get the benefit of siring the next offspring.”

Closely related species that differ in infanticide and testes size include chimpanzees (males commit infanticide) versus bonobos (males have not been observed to kill offspring). Bonobos have testes that are roughly 15% larger than those of chimpanzees.

Male Canadian Townsend voles don’t commit infanticide, and have 50% larger testes compared to infanticidal males of close relatives the North American meadow voles, says Lukas.

He conducted the research with his colleague Dr Elise Huchard, now based at the CNRS Centre d’Ecologie Fonctionnelle et Evolutive in Montpellier.

Fifty years ago, observations of wild Hanuman langurs shattered previous depictions of monkey groups as peaceful, supportive societies, says Lukas, as new males that had just taken control of a group of females frequently killed all juveniles.

Subsequent observations have accumulated over the years on various mammals to show that infanticide by males is a widespread phenomenon, occurring in species from house mice to lions and gorillas. In some species, he says, the biggest risk faced by infants might not actually be predators or diseases, but the adult males of their own species.

In the latest study, Lukas and Huchard compiled and compared detailed field observations for 260 mammalian species to show that male infanticide occurs in species where sexual conflict is most intense, and reproduction is monopolised by a minority of males. The researchers’ findings indicate that infanticide is a manifestation of sexual conflict in mammalian social systems.

“While it had previously been suggested that infanticide might be an evolutionary driver in mammalian societies — leading to females allying themselves with other females or forming bonds with a specific male in order to defend their offspring — we’ve now shown that this isn’t the case: male infanticide is a consequence of variation in sociality, most commonly occurring in species where both sexes live together in stable groups,” said Lukas.

The researchers say the new study supports the idea that infanticide isn’t a general trait present in all species, but is strategic and occurs only when it is advantageous to males. The study reveals the reversible nature of male infanticide, and that it is successfully prevented by the ‘paternity dilution’ strategy of female sexual promiscuity.

Added Huchard: “Male infanticide appears and disappears over evolutionary times according to the state of the evolutionary arms race between the sexes. Although infanticide may not have contributed to shape the diversity of mammalian social systems, it has deeply influenced the evolution of sexual behaviour and sex roles.

“This study also highlights that some of the greatest challenges faced by mammals during their lifetime come from others of their own species.”

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Single-dose, needle-free ebola vaccine provides long-term protection in macaques

Scientists have demonstrated for the first time that a single-dose, needleless Ebola vaccine given to primates through their noses and lungs protected them against infection for at least 21 weeks. A vaccine that doesn’t require an injection could help prevent passing along infections through unintentional pricks.

They report the results of their study on macaques in the ACS journal Molecular Pharmaceutics.

Maria A. Croyle and colleagues note that in the current Ebola outbreak, which is expected to involve thousands more infections and deaths before it’s over, an effective vaccine could help turn the tide. Even better, taking the needle out of the inoculation process could also help prevent the accidental transmission of Ebola, as well as other diseases, such as HIV, that might otherwise spread from unintentional needle pricks and unsafe handling of medical wastes. Other vaccines are currently under development to fight the virus, but they require an injection. Croyle’s team tested an adenovirus-based Ebola vaccine using a respiratory delivery route.

The researchers gave a novel formulation of an Ebola vaccine to several macaques then exposed them to the virus more than four months later. All three of the animals that received the vaccine through the nose and via a catheter into their airways did not fall ill. However, since special equipment and training are required for the current respiratory delivery method, the scientists conclude that further work is needed if this formula, or an under-the-tongue version, is to be used eventually in large-scale immunization campaigns.

The authors acknowledge funding from the National Institutes of Health.

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Tools and primates: Opportunity, not necessity, is the mother of invention

When food is scarce, tool use among non-human primates does not increase. This counterintuitive finding leads researchers to suggest that the driving force behind tool use is ecological opportunity — and that the environment shapes development of culture.

Whether you’re a human being or an orangutan, tools can be a big help in getting what you need to survive. However, a review of current research into the use of tools by non-human primates suggests that ecological opportunity, rather than necessity, is the main driver behind primates such as chimpanzees picking up a stone to crack open nuts.

An opinion piece by Dr Kathelijne Koops of the University of Cambridge and others, published today (12 November 2014) in Biology Letters, challenges the assumption that necessity is the mother of invention. She and her colleagues argue that research into tool use by primates should look at the opportunities for tool use provided by the local environment.

Koops and colleagues reviewed studies on tool use among the three habitual tool-using primates — chimpanzees, orangutans and bearded capuchins.

Chimpanzees use a variety of tools in a range of contexts, including stones to crack open nuts, and sticks to harvest aggressive army ants. Orangutans also use stick tools to prey on insects, as well as to extract seeds from fruits. Bearded capuchin monkeys living in savannah-like environments also use a variety of tools, including stones to crack open nuts and sticks to dig for tubers.

The researchers’ review of the published literature, including their own studies, revealed that, against expectations, tool use did not increase in times when food was scarce. Instead, tool use appears to be determined by ecological opportunity with calorie-rich but hard-to-reach foodstuffs, such as nuts and honey, appearing to act as an incentive for an ingenious use of materials.

“By ecological opportunity, we mean the likelihood of encountering tool materials and resources whose exploitation requires the use of tools. We showed that these ecological opportunities influence the occurrence of tool use. The resources extracted using tools, such as nuts and honey, are among the richest in primate habitats. Hence, extraction pays off, and not just during times of food scarcity,” said Koops.

Tool use — and transmission of tool-making and tool-using skills between individuals — is seen as an important marker in the development of culture. “Given our close genetic links to our primate cousins, their tool use may provide valuable insights into how humans developed their extraordinary material culture and technology,” said Koops.

It has been argued that culture is present among wild primates because simple ecological and genetic differences alone cannot account for the variation in behaviour — such as tool use — observed across populations of the same species.

Koops and co-researchers argue that this ‘method of exclusion’ may present a misleading picture when applied to the material aspects of culture.

“The local environment may exert a powerful influence on culture and may, in fact, be critical for understanding the occurrence and distribution of material culture. In forests with plenty of nut trees, we are more likely to find chimpanzees cracking nuts, which is the textbook example of chimpanzee material culture,” said Koops.

“Our study suggests that published research on primate cultures, which depend on the ‘method of exclusion’, may well underestimate the cultural repertoires of primates in the wild, perhaps by a wide margin. We propose a model in which the environment is explicitly recognised as a possible influence on material culture.”

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Baby Gorilla Crushed By Door At San Francisco Zoo

The San Francisco Zoo’s baby gorilla, Kabibe, died Friday after trying to dart through a closing hydraulic door.

The zoo describes the death as a “rare accident,” according to the zoo’s website.

The door’s custom-made manual shut-off switch was working properly when tested after the death, reports The San Francisco Chronicle.

Kabibe was born in July 2013 into captivity and was among the six other gorillas living at the zoo.

Kabibe was one of the biggest draws for zoo visitors, according to the zoo website.

Her mother had not bonded with the baby at first, and Kabibe required four months of human care after her birth before she was introduced to her grandmother.

Full story here .

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Ebola in Democratic Republic of the Congo: A new strain of the virus

While an Ebola epidemic has been raging in West Africa since March 2014, an outbreak of this haemorrhagic fever occurred in the Democratic Republic of the Congo (DRC) in August, leaving fears over the virus’ spread to Central Africa. A study by the IRD, the Institut Pasteur, the CNRS, the CIRMF in Gabon, the INRB in DRC and the WHO, published in the New England Journal of Medicine on 16 October 2014, confirms that it is an Ebola epidemic. However, this particular epidemic is due to a local strain of the virus, different from the one rife in the West of the continent. While this result shows the two epidemics are not linked, it illustrates the speed at which the disease has emerged. It is therefore urgent that we understand just how the disease is spread.

With the world’s eyes focused on West Africa, where several countries have been affected since March 2014 by the most serious Ebola epidemic ever witnessed, the WHO reported another outbreak in the North of the Democratic Republic of the Congo on 24 August. It was therefore essential to verify whether this second epidemic stemmed from that of West Africa, indicating its spread to Central Africa.

A different strain

Researchers from the IRD, the Institut Pasteur, the CNRS, the CIRMF in Gabon and the INRB in the DRC, in collaboration with WHO experts, reveal that it is a new outbreak of haemorrhagic fever, separate from the West-African outbreak. The CIRMF has performed whole genome sequencing of the virus responsible using a high-throughput sequencer that is unique to Sub-Saharan Africa. It confirms that it is a virus from the Ebola species, but shows that the Congolese strain is different from the one in West Africa. Moreover, it appears to be very similar to those that ravaged in the DRC and Gabon between 1995 and 1997.

A contained epidemic

This result means that the Congolese outbreak is due to a local viral strain, which has been controlled. This epidemic began on 26 July 2014 when a woman fell ill a few days after cutting up a monkey found dead in the forest. To date, 70 cases have been confirmed, including 42 deaths, giving a fatality rate of around 60%, similar to that observed in West Africa. The epidemic peak was observed in the week of 24 August 2014. Thanks to the protection measures implemented by the Congolese health authorities — isolation of patients, protection of medical staff, instructing the populations to avoid all body contact — the epidemic now appears to be contained.

This recent rise in Ebola epidemics shows that the likelihood of the virus being passed on from animal reservoir to humans is increasing. We therefore urgently need to gain a better understanding of the ways in which the virus circulates (seasonal or other) within its natural reservoir and the factors that govern the virus’ transfer from one animal species to another or to humans. Better knowledge of these parameters would enable alert thresholds to be defined and epidemics to be predicted, which could prove invaluable to the rapid implementation of control measures.

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Humans, baboons share cumulative culture ability

The ability to build up knowledge over generations, called cumulative culture, has given mankind language and technology. While it was thought to be limited to humans until now, researchers from the Laboratoire de psychologie cognitive (CNRS/AMU), working in collaboration with colleagues at the University of Edinburgh (UK), have recently found that baboons are also capable of cumulative culture. Their findings are published in Proceedings of the Royal Society B on 5 November 2014.

Humankind is capable of great accomplishments, such as sending probes into space and eradicating diseases; these achievements have been made possible because humans learn from their elders and enrich this knowledge over generations. It was previously thought that this cumulative aspect of culture — whereby small changes build up, are transmitted, used and enriched by others — was limited to humans, but it has now been observed in another primate, the baboon.

While it is clear that monkeys like chimpanzees learn many things from their peers, each individual seems to start learning from scratch. In contrast, humans use techniques that evolve and improve from one generation to the next, and also differ from one population to another. The origin of cumulative culture in humans has therefore remained a mystery to scientists, who are trying to identify the necessary conditions for this cultural accumulation.

Nicolas Claidière and Joël Fagot, of the Laboratoire de psychologie cognitive, conducted the present study at the CNRS Primatology Center in Rousset, southeastern France. Baboons live in groups there and have free access to an area with touch screens where they can play a “memory game” specifically designed for the study. The screen briefly displays a grid of 16 squares, four of which are red and the others white. This image is then replaced by a similar grid, but composed of only white squares, and the baboons must touch the four squares that were previously red. Phase one of the experiment started with a task-learning period in which the position of the four red squares was randomized. Phase two comprised a kind of visual form of “Chinese whispers” wherein information was transmitted from one individual to another. In this second phase, a baboon’s response (the squares touched on the screen) was used to generate the next grid pattern that the following baboon had to memorize and reproduce, and so on for 12 “generations.”

The researchers, in collaboration with Simon Kirby and Kenny Smith from the University of Edinburgh, noted that baboons performed better in the phase involving a transmission chain (compared with random testing, which continued throughout the period of the experiment): success rate (1) increased from 80% to over 95%. Due to errors by the baboons, the patterns evolved between the beginning and the end of each chain. Yet to the surprise of researchers, the random computer-generated patterns were gradually replaced by “tetrominos” (Tetris®-like shapes composed of four adjacent squares), even though these forms represent only 6.2% of possible configurations! An even more surprising result was that the baboons’ performance on these rare shapes was poor during random testing, but increased throughout the transmission chain, during which the tetrominos accumulated. Moreover, when the experiment was replicated several times, the starting patterns did not lead to the same set of tetrominos. This study shows that, like humans, baboons have the ability to transmit and accumulate changes over “cultural generations” and that these incremental changes, which may differ depending on the chain, become structured and more efficient.

Researchers have ensured that all the necessary conditions were present to observe a type of cumulative cultural evolution in non-human primates, with its three characteristic properties (progressive increase in performance, emergence of systematic structures, and lineage specificity). These results show that cumulative culture does not require specifically human capacities, such as language. So why have no examples of this type of cultural evolution been clearly identified in the wild? Perhaps because the utilitarian dimension of non-human primate culture (e.g., the development of tools) hinders such evolution.

(1) The task was considered successful if at least 3 out of 4 squares were correctly memorized.

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Malaria from monkeys now dominant cause of human malaria hospitalizations in Malaysia

The majority of malaria hospitalizations in Malaysia are now caused by a dangerous and potentially deadly monkey-borne parasite once rarely seen in humans, and deforestation is the potential culprit in a growing number of infections that could allow this virulent malaria strain to jump from macaque monkeys to human hosts, according to research presented today at the American Society of Tropical Medicine and Hygiene (ASTMH) Annual Meeting.

An analysis of malaria patients hospitalized in Malaysian Borneo in 2013 showed that 68 percent had been sickened by Plasmodium knowlesi, said Balbir Singh, PhD, director of the Malaria Research Center at the University of Malaysia in Sarawak. The parasite is increasingly associated with malaria deaths and is three times more frequent as a cause of severe malaria in Borneo than the more common P. falciparum parasite that is currently considered the world’s most deadly form of the disease.

The main host of knowlesi malaria has been the long-tailed and pig-tailed macaques found in the tropical forests of Malaysia and elsewhere in Southeast Asia. The infections are concentrated in areas of Malaysia where over the last decade massive loss of native forest to timber and palm oil production has led to substantially increased human interactions with macaques. That puts knowlesi malaria in the company of a growing list of dangerous emerging and re-emerging diseases — including Ebola and AIDS — that are being passed from animals to humans as development peels back more and more layers of tropical forest previously uninhabited by humans.

“This is a form of malaria that was once rarely seen in people, but today, in some remote areas of the country, all of the indigenous malaria cases we are seeing are caused by the P. knowlesi parasite,” Singh said. “If the number of cases continue to increase, human-to-human transmission by mosquitoes becomes possible. In fact, this may already have happened, which would allow P. knowlesi malaria to spread more easily throughout Southeast Asia.”

Evidence to date has strongly suggested that victims of P. knowlesi malaria have been bitten by mosquitoes that had first bitten an infected macaque, making humans a dead-end host for the parasite. Of concern, however, is recent research that the parasite could change so that it can jump from person to person via mosquito bites, without requiring a monkey as part of its life cycle. Laboratory tests in the 1960s indicated that a mosquito variety in Malaysian Borneo that carries the two most common human malaria parasites — P. falciparum and P. vivax — also can spread the knowlesi parasite. Moreover, P. knowlesi was recently found in Vietnam in mosquitoes that transmit falciparum and vivax malaria, raising the possibility that human-to-human transmission is already occurring.

P. knowlesi is the fifth species of malaria known to infect humans in nature. The parasite causes only mild malaria in macaques, Singh said, but in people it is the fastest replicating malaria parasite, multiplying every 24 hours in the blood.

The majority of the macaques carrying the parasite once lived in remote forested regions that saw little human activity or settlements. This has changed over the last ten years as a result of significant deforestation in Malaysia. According to a 2013 study in the journal Science, Malaysia lost about 47,000 square kilometers of forest between 2000 and 2012, or about 14 percent of its total land area, which environmentalists blame on logging and conversion of native forests to palm oil plantations.

At the ASTMH meeting, a team from the London School Hygiene and Tropical Medicine is presenting preliminary findings from an ongoing study that is outfitting people in the Sabah region of Malaysia with GPS tracking devices to explore the role of human movements into different macaque and mosquito habitats on the spread of P. knowlesi infections.

Researchers have been warning for decades that more frequent human incursions into undeveloped tropical forests will significantly increase the threat from diseases that could spread far beyond the forest canopy. The current Ebola outbreak is linked to a growing number of people living and hunting in forested areas and consuming “bush meat” from infected animals, chiefly chimpanzees. Meanwhile, illegal mining operations in tropical forests have been linked to the recent resurgence of malaria in Venezuela and may have intensified the rise of drug resistant malaria in Thailand.

These interactions are prompting a growing interest in research that probes the threat of disease from multiple vantage points — including economical, biological, and anthropological — an approach known as One Health.

Singh said that P. knowlesi malaria is currently a major public health problem in Malaysia, as it is causing illness serious enough to require medical treatment in about two thousand people a year.

“But the P. knowlesi strain of malaria should stay within Southeast Asia as there are no mosquitoes outside the region capable of carrying these parasites,” he said.

Singh also pointed out that, in terms of overall burden of disease, knowlesi malaria still ranks far behind dengue fever. Infections and deaths with that mosquito-borne disease have more than tripled in Malaysia in just the last year. The rising threat of the P. knowlesi parasite, however, which is carried by mosquitoes that prey on humans when they are outdoors, presents a new challenge for the broader effort to control and eliminate malaria in Southeast Asia — a fight that has been focused on using bed nets and indoor spraying to prevent malaria infections caused mainly by mosquitoes that attack indoors and at night. Malaria control campaigns also have not faced a malaria strain that is entrenched in a large animal population.

“Controlling a zoonotic — meaning an animal-to-human infection — carried by outdoor feeding mosquitoes is almost impossible with currently used methods,” Singh said.

“These intriguing results are yet another example of the complexity and diversity of the interaction between man, his activities, parasites, and mosquitoes. P. knowlesi is now a significant cause of human malaria in Malaysian Borneo that must be addressed across multiple levels: research, development, implementation, funding and evidence-based policies,” said Alan J. Magill, MD, FASTMH, president of the American Society of Tropical Medicine and Hygiene.

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Immune cells proposed as HIV hideout don’t last in primate model

Where does HIV hide? Antiretroviral drugs can usually control the virus, but can’t completely eliminate it. So any strategy to eradicate HIV from the body has to take into account not only the main group of immune cells the virus targets, called CD4 or helper T cells, but other infected cells as well.

New research from Yerkes National Primate Research Center, Emory University, sheds light on the question of which cells support viral replication and persistence, and the answers have implications for future efforts to eliminate HIV from the body in human patients.

The results were published Oct. 30 in the journal PLOS Pathogens.

“Our results have implications for efforts to cure HIV,” says lead author Mirko Paiardini, PhD, assistant professor of pathology and laboratory medicine at Emory University School of Medicine and Yerkes National Primate Research Center. “Our findings suggest that therapeutic strategies aimed at stimulating infected macrophages may facilitate viral elimination.”

Researchers at Yerkes looked at what happens when rhesus macaques have CD4 T cells removed from their immune systems before infection by HIV’s cousin SIV. They found that another type of immune cell, called macrophages, then becomes heavily infected by SIV. Infected cells are present in lymph nodes, intestine and brain as well as in the blood.

However, the macrophages live shorter than expected based on previous research studies, which calls into question the idea that the macrophages could serve as a long-term hideout when someone is infected by HIV but receiving antiretroviral drugs.

“Among HIV researchers, there has been a lot of debate about the contribution of macrophages to the HIV reservoir,” Paiardini says. “We show that in the absence of CD4 T cells, macrophages can be heavily infected by SIV, which supports a role for macrophages in viral infection. However, when infected at high levels, macrophages become short-lived cells in vivo, with an average lifespan of 1.3 days. Thus, if validated in the setting of HIV infection in humans, our data support a model in which macrophages do not constitute the long-lived reservoir (in order of weeks) that has been proposed.”

The researchers also found evidence that in macaques with depleted CD4 T cells, SIV is infecting microglial cells in the brain, otherwise rarely seen.

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‘Gorillas in the Crossfire’

In a Mother’s Milk, Nutrients, and a Message, Too

Ebola, Marburg viruses edit genetic material during infection

Filoviruses like Ebola “edit” genetic material as they invade their hosts, according to a study published this week in mBio®, the online open-access journal of the American Society for Microbiology. The work, by researchers at the Icahn School of Medicine at Mount Sinai, the Galveston National Laboratory, and the J. Craig Venter Institute, could lead to a better understanding of these viruses, paving the way for new treatments down the road.

Using a laboratory technique called deep sequencing, investigators set out to investigate filovirus replication and transcription, processes involved in the virus life cycle. They studied the same Ebola virus species currently responsible for an outbreak in West Africa, and also analyzed a related filovirus, Marburg virus, that caused a large outbreak in Angola in 2005 and recently emerged in Uganda. The scientists infected both a monkey and human cell line with both viruses, and analyzed the genetic material produced by each virus, called RNA.

Their results highlight regions in Ebola and Marburg virus RNAs where the polymerase of the virus (a protein that synthesizes the viral RNA) stutters at specific locations, adding extra nucleotides (molecules that form the building blocks of genetic material like DNA and RNA), thereby “editing” the new RNAs. The study found new features at a described RNA editing site in the Ebola glycoprotein RNA, which makes the protein that coats the surface of the virus. Their work also identified less frequent but similar types of editing events in other Ebola and Marburg virus genes — the first time this has been demonstrated. Because of these messenger RNA modifications, Ebola and Marburg are potentially making proteins “that we previously didn’t realize,” said Christopher F. Basler, PhD, senior study author and professor of microbiology at Mount Sinai.

“The bottom line is we know these changes occur but we don’t yet know what it really means in the biology of the virus,” Basler said. There are many aspects of how the viruses replicate that aren’t yet understood, he said, “so we need a complete description of how they grow to develop new strategies used to treat the infections.”

The study also illustrated how the filoviruses express their genes, and deep sequencing identified all seven messenger RNAs within six hours of infection.

“Our study suggests that the Ebola virus is making forms of proteins previously undescribed,” said lead author Reed Shabman, PhD, an assistant professor at the J. Craig Venter Institute in Rockville, Md. Shabman was at Mount Sinai when the study was initiated. “Understanding the products of these viruses is critical to understanding how to target them.”

In addition, he said, proteins produced by the glycoprotein editing site are associated with virulence in animals, “so it’s of great interest to understand how that protein is made, and in as much detail as possible.”

“We infer that this probably contributes to how the virus grows in a person or an animal,” Basler said.

Further study is needed to determine the biological significance of these findings and how these processes are regulated, Basler said.

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Lemurs: Gardeners of Madagascar rainforest at risk

A majority of Madagascar’s 101 species of lemurs are threatened with extinction, and that could have serious consequences for the rainforests they call home. A new study by Rice University researchers shows the positive impacts lemurs can have on rainforest tree populations, which raises concerns about the potential impact their disappearance could have on the region’s rich biodiversity.

A large proportion of trees in Madagascar’s rainforest have fruits eaten by lemurs. Lemurs in turn disperse the seeds of their fruit trees throughout the forest with their scat. Such dispersal can play a crucial role for a tree species’ ability to regenerate, but effects are poorly understood, especially when there are multiple dispersers.

For the tree, the evolutionary advantage of having animal-dispersed seeds may be that the seeds land well away from their parent trees where survival is low or that seeds are directed into spots where they are the most likely to sprout and survive.

Amy Dunham, an assistant professor of biosciences, and graduate student Onja Razafindratsima set out to detail the symbiotic relationship between fruit-eating lemurs and the trees that feed them through a three-year study in a rainforest in southeastern Madagascar.

Their data from observations, experiments and mathematical models demonstrate that seeds of a common canopy tree have a 300 percent higher chance of sprouting and becoming a sapling when dispersed by lemurs versus simply falling to the ground. One of the three lemur species is particularly good at dropping seeds in spots that are most advantageous for sprouting and survival. Other lemurs are not so selective, but still benefit the tree by moving seeds away from the parent tree. By acting as forest gardeners, these animals give the tree’s population a boost.

The study appeared online in the Ecological Society of America journal Ecology.

As part of the study, the researchers followed the seed-dispersal patterns of three of Madagascar’s lemur species: the red-fronted brown lemur, the red-bellied lemur and the southern black-and-white ruffed lemur. That meant tracking and observing groups of lemurs as the animals leaped from tree to tree through the forest, dined in the 65-foot-high canopies and dropped their undigested seeds at ground level.

Razafindratsima led the study as part of a thesis project she expects to complete early next year. She built a team of local researchers near Ranomafana National Park, the home of Centre ValBio, a research station founded by Dunham’s former Ph.D. adviser, primatologist Patricia Wright.

“We have a team of up to 10 local villagers who are trained to do research,” said Razafindratsima, a native of Madagascar. “Their exceptional knowledge of the forest is very important to us when we’re trying to track lemurs and identify seeds and seedlings in a forest with over 300 species of trees.”

The research team tracked 24 groups of lemurs over a year without the benefit of radio collars, said Razafindratsima, who keeps in touch with her team via phone and Skype when she’s at Rice. She said the study sites were as close as a short hike from Centre ValBio and as far as a two-day trek through steep terrain that entailed camping overnight.

In addition to tracking lemurs and their dispersed seeds, the research team spent three years carrying out experiments on seed sprouting and survival. They found that dispersal by lemurs dramatically increased the odds that seeds would take root and survive. In particular, the red-fronted brown lemurs tended to drop seeds away from their parent trees and in places where there were gaps in the canopy. This gave individual seeds the best shot at taking root.

Dunham said trees benefit from the wide dispersal of their seeds, and for some species in Madagascar, lemurs are the primary or only animal that can distribute those seeds. As the largest fruit-eaters in the system, these lemurs swallow seeds that may be too large for other fruit-eating animals, such as birds or bats.

“Seeds away from the parent tree survive better because there’s less competition among seedlings,” Razafindratsima said. “If they’re close by the parent, they may also share the same natural enemies, like soil pathogens and seed predators, so there’s higher mortality.”

Trees that lose their dispersers will simply drop their seeds to the ground beneath their canopies, where chances of survival are slim, Dunham said. “Lemurs fill an important role as the gardeners for these trees. By ensuring that some seeds land in spots suitable for germination and survival, they increase the ability of these trees to replace themselves”

Dunham hopes the study will contribute to growing efforts to protect lemurs, and therefore the rainforest, which has been impacted in recent years by economic and political instability. She noted grassroots efforts within Madagascar led to the first World Lemur Festival in late October to celebrate and protect the animals and their habitats in Madagascar.

“What got us interested is that frugivorous lemur populations are declining across the island, and we know very little about how these seed dispersers actually affect tree populations,” she said. “Once we understand that better, maybe we’ll have a better idea of how the community might change if the lemurs disappear.

“If some species suddenly lose their dispersers, but others dispersed by birds or the wind are doing fine, it may change population trajectories and alter which tree species are dominant in a community. To understand what happens when these species are lost, we need to understand their role in the ecosystem,” she said.

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Nasal spray vaccine has potential for long-lasting protection from Ebola virus

A nasal vaccine in development by researchers at The University of Texas at Austin has been shown to provide long-term protection for non-human primates against the deadly Ebola virus. Results from a small pre-clinical study represent the only proof to date that a single dose of a non-injectable vaccine platform for Ebola is long-lasting, which could have significant global implications in controlling future outbreaks. This work is being presented Nov. 5 at the 2014 American Association of Pharmaceutical Scientists (AAPS) Annual Meeting and Exposition, the world’s largest pharmaceutical sciences meeting, in San Diego, Nov. 2-6.

The Ebola virus is an often fatal illness that is spread among the human population via direct contact with blood or bodily fluids from an infected individual. The current Ebola outbreak in Western Africa is the largest and most complex epidemic since the virus was first discovered in 1976, according to the World Health Organization. With a fatality rate currently as high as 70%, officials are declaring this outbreak a public health emergency of international concern.

Maria Croyle, a professor in the College of Pharmacy at The University of Texas at Austin, Kristina Jonsson-Schmunk, a graduate student in pharmacy, and colleagues at the university developed a nasal formulation that improved survival of immunized non-human primates from 67 percent (2 out of 3) to 100 percent (3 out of 3) after challenge with 1,000 plaque forming units of Ebola Zaire 150 days after immunization. This is important since only 50 percent of the primates given the vaccine by the standard route (intramuscular injection) survived challenge.

“Ebola causes devastating outbreaks with fatality rates of 25 — 90 percent in Africa and Asia. Although progress has been made in understanding the virus’ biology, no licensed vaccines or treatments currently exist. There is a desperate need for a vaccine that not only prevents the continued transmission from person to person, but also aids in controlling future incidents,” said Jonsson-Schmunk. “The main advantage of our vaccine platform over the others in clinical testing is the long-lasting protection after a single intranasal dose. This is important since the longevity of other vaccines for Ebola that are currently being evaluated is not fully understood. Moreover, the nasal spray immunization method is more attractive than a needle vaccine given the costs associated with syringe distribution and safety.”

The next stage of Dr. Croyle’s research is a Phase I clinical trial that tests the effectiveness of their vaccine in human subjects. They will also further explore preliminary data they have collected for administration of the vaccine as a thin film under the tongue in non-human primates.

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The above story is based on materials provided by American Association of Pharmaceutical Scientists . Note: Materials may be edited for content and length.

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First Immature form of HIV seen at high resolution surprises researchers

Scientists at the European Molecular Biology Laboratory (EMBL) in Heidelberg, Germany and collaborators from Heidelberg University, in the joint Molecular Medicine Partnership Unit, have obtained the first structure of the immature form of HIV at a high enough resolution to pinpoint exactly where each building block sits in the virus. The study, published online today in Nature, reveals that the building blocks of the immature form of HIV are arranged in a surprising way.

“The structure is definitely different from what we’d expected,” says John Briggs from EMBL, who led the work. “We assumed that retroviruses like HIV and Mason-Pfizer Monkey Virus would have similar structures, because they use such similar building blocks, but it turns out that their immature forms are surprisingly different from each other. At this point, we don’t really know why.”

Briggs and colleagues used cryo-electron microscopy to study the protein lattice that surrounds the virus’ genetic material. After infecting one of the cells in our immune system, HIV replicates, producing more copies of itself, each of which has to be assembled from a medley of viral and cellular components into an immature virus. This is the form that leaves the cell. The protein building blocks that make up the virus are then rearranged into the virus’ mature form, which can infect other cells.

The first cryo-electron microscopy images of immature HIV, obtained at EMBL in the 1990s, surprised researchers by showing that the virus did not have a regular symmetrical structure, as had been assumed. That meant it was going to be difficult to get a detailed picture of the structure of its protein lattice. Two decades on, by optimising both how data is collected at the microscope and how it is analysed, Florian Schur, a PhD student in Briggs’ lab, has now achieved an unprecedentedly detailed structure.

With this structure in hand, scientists have a basis to probe further. They can use it to decide where to focus efforts for achieving the even greater detail needed to explore potential drug targets, for instance. It will also enable researchers to understand how mutations might influence how the virus assembles. And the techniques themselves can be applied to a variety of questions.

“This approach offers so many possibilities,” says Schur. “You can look at other viruses, of course, but also at complexes and proteins inside cells, with a whole new level of detail.”

In future, the EMBL scientists will use the approach to look at other viruses and at the vesicles that transport material inside cells. They also aim to push the techniques even further, to allow them to see other parts of the viral proteins that are currently beyond their reach, but which they suspect play an important role in HIV maturation.

“In the long term, we’d also like to investigate how drugs which are known to inhibit virus assembly and maturation actually work,” Briggs concludes.

The video that accompanies this release is available on YouTube: http://ift.tt/1xTRsK8.

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The above story is based on materials provided by European Molecular Biology Laboratory (EMBL) . Note: Materials may be edited for content and length.

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