Tag Archives: monkeys

Vaccine tests in China protected monkeys from coronavirus

More than 2.6 million people around the world have so far been infected with the coronavirus. As it expands, all hopes are on creating a vaccine, with trials currently taking place in different parts of the world.

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In China, researchers at Sinovac Biotech, a private company based in Beijing, have successfully protected monkeys with a coronavirus vaccine. It’s the first time that a trial has worked on an animal and will now be followed by trials in humans.

The team gave two different doses of their COVID-19 vaccine to eight rhesus macaque monkeys. Three weeks later, the group introduced SARS-CoV-2, the virus that causes COVID-19, into the monkeys’ lungs but none developed a full-blown infection.

The monkeys that were given the highest dose of vaccine had the best response. A week after receiving the virus, researchers could not detect it in the pharynx or lungs of any of them. Some of the lower dosed animals had a “viral blip” but also appeared to have controlled the infection.

Despite the limited scale of trial — only a few monkeys were part of it, — Meng Weining, Sinovac’s senior director for overseas regulatory affairs, told Science Magazine that the results “give us a lot of confidence” that the vaccine will work in humans.

Florian Krammer, a virologist at the Icahn School of Medicine at Mount Sinai, also told the journal that the “old-school” nature of the vaccine — a formula of a chemically inactive version of the virus — means it could break down barriers to access.

“I like it,” Krammer said. “This is old school but it might work. What I like most is that many vaccine producers, also in lower–middle-income countries, could make such a vaccine.”

Nevertheless, the University of Pittsburgh researcher Douglas Reed, who is developing and testing COVID-19 vaccines in monkey studies, told Science Magazine that the number of animals was too small to yield statistically significant results.

Another concern is that monkeys do not develop the most severe symptoms that COVID-19 causes in humans. The Sinovac researchers acknowledged that “it’s still too early to define the best animal model for studying SARS-CoV-2,” but noted that unvaccinated macaques given the virus “mimic COVID-19-like symptoms.”

Earlier animal experiments with vaccines against other coronaviruses had found that low antibody levels could lead to aberrant immune responses when an animal was given the pathogens. But the Sinovac team did not find any evidence of lung damage in vaccinated animals.

While vaccines can help end the coronavirus pandemic, it’s impossible to put a clear timeline on their development. We will have to deal with the virus for the foreseeable future, and there’s no guarantee that we will have widespread vaccinations in 2021.

The most optimistic version we’ve seen comes from Oxford scientists, who said that we may have a vaccine by September and have already started trials. The most pessimistic is that we’ll never have a vaccine. The reality is probably somewhere in between.

The work by the Chinese researchers was published on the preprint server bioRxiv.

Credit: Wikimedia Commons

Grumpy old monkeys are more picky with who they call friends, just like humans

Credit: Wikimedia Commons

Credit: Wikimedia Commons

Though they’re separated by 25 million years of evolution, monkeys and humans share at least one common fact of life: both choose to have a less engaged social life at old age.

The conclusion was made by researchers at the German Primate Center in Goettingen, Germany, who followed a group of Barbary macaques at a French wildlife park. The monkeys varied from age 4 to age 29 (that’s equivalent to age 105 in humans).

During the course of several weeks, the team recorded how the monkeys interacted with objects like novel toys baited with food, how often they groomed friends or fought and how they responded to social cues like photos and haul recordings from friends or strangers.

As the monkeys aged past their childhoods and began lives as adults — essentially when they reached sexual maturity — their interest in toys waned. The pensioner monkeys, or those older than 20, had the fewest “friends” and engaged in social contact rarely, akin to how our elderly prefer to stick to themselves and the few ‘true’ friendships they have left.

It’s important to note that while the old monkeys got quite grumpy with old age, they still were very much aware of their surroundings. They responded to photos and audio recordings of other monkeys and hissed during fights. And while they groomed other monkeys far less frequently, the elderly were often groomed by younger monkeys.

Psychologists say that humans become more choosy with how they decided to spend their time once with old age. When you realize you have little time to spend, you choose to use that time more wisely. You visit the same restaurant and are less inclined to engage socially with mere acquaintances. But a monkey, we suspect, is not aware of its own mortality. Yet, the pattern of similarities between old monkeys and humans is striking.

Dr.  Julia Fischer, one of the lead authors of the study, says we might just be rationalizing an inherent biological construct. Both monkeys and humans might simply have too little energy left once they hit their golden years, and thus unable to reserve resources for new relationships. There’s also a tendency to become more risk adverse with old age, which might also explain social withdrawal.

“Our behaviors that seem very much the result of our deliberation and choice,” said Dr. Freund, “might be more similar to our primate ancestors than we might think.”

Comparison of footfall sequence in primate (baboon, above) and nonprimate (cat, below). Footfall sequence is depicted numerically, beginning with the right hind limb in each animal. The primate is walking in diagonal sequence (RH-LF-LH-RF), and the nonprimate is walking in lateral sequence (RH-RF-LH-LF). Image from Muybridge E (1887) . Animal Locomotion: An Electro-photographic Investigation of Consecutive Phases of Animal Movements, 1872-1885: 112 Plates. Published under the auspices of the University of Pennsylvania.

The family that walks on all-fours does not constitute reverse evolution

bbc_walk_on_all_four

In 2006 , the BBC aired a fascinating documentary that featured that featured a family of five siblings from a remote corner of Turkey that remarkably solely moved about by walking on all fours. Many anthropologists of the time saw this behavior as evidence of reverse evolution and sought to extensively study the phenomenon in order to gain insights on how human bipedal locomotion can to be. Researchers from the US, however, claim they have proof that the family that walks on all-fours, as they’re commonly referred to in literature, simply adapted to an unfortunate neurological syndrome and their behavior does not constitute backward evolution.

Here’s the documentary:

At the time of their discovery, Uner Tan of Cukurova University asserted that the family members’ condition,  called Uner Tan Syndrome (UTS), acts like a model for reverse evolution, mimicking the way non-human primates, like monkeys or apes, move about. This view, while it gained considerable traction, has been repeatedly countered by studies which found people with UTS simply adapted to the impaired ability to walk bipedally.

[RELATED] Early hominds started walking on two legs because of shifting geology

The team, comprised of researchers at Northeast Ohio Medical University, University of Arizona, New York University, carefully analyzed footage of 518 quadrupedal walking strides and compared them to walking patterns of healthy adults who were asked to move around a laboratory on all fours. More than 98% of participants, whether they were asked to walk on all fours or were forced to because of UTS, walked in lateral sequences – they placed a foot down, then the corresponding hand from the same side, before performing the same sequence on the other side. Non-human primates, however, use what’s called a diagonal quadruped sequence,  in which they put down a foot on one side and then a hand on the other side, continuing that pattern as they move along.

“Although it’s unusual that humans with UTS habitually walk on four limbs, this form of quadrupedalism resembles that of healthy adults and is thus not at all unexpected,” says  Liza Shapiro, an anthropologist at The University of Texas at Austin. “As we have shown, quadrupedalism in healthy adults or those with a physical disability can be explained using biomechanical principles rather than evolutionary assumptions.”

Comparison of footfall sequence in primate (baboon, above) and nonprimate (cat, below). Footfall sequence is depicted numerically, beginning with the right hind limb in each animal. The primate is walking in diagonal sequence (RH-LF-LH-RF), and the nonprimate is walking in lateral sequence (RH-RF-LH-LF). Image from Muybridge E (1887) . Animal Locomotion: An Electro-photographic Investigation of Consecutive Phases of Animal Movements, 1872-1885: 112 Plates. Published under the auspices of the University of Pennsylvania.

Comparison of footfall sequence in primate (baboon, above) and nonprimate (cat, below). Footfall sequence is depicted numerically, beginning with the right hind limb in each animal. The primate is walking in diagonal sequence (RH-LF-LH-RF), and the nonprimate is walking in lateral sequence (RH-RF-LH-LF). Image from Muybridge E (1887) . Animal Locomotion: An Electro-photographic Investigation of Consecutive Phases of Animal Movements, 1872-1885: 112 Plates. Published under the auspices of the University of Pennsylvania.

The researchers believe initial research in favor of reverse evolution was misguided by confusing  diagonal sequence with diagonal couplets. Sequence refers to the order in which the limbs touch the ground, while couplets (independent of sequence) indicate the timing of movement between pairs of limbs. People with UTS more frequently use diagonal couplets than lateral couplets, but the sequence associated with the couplets is almost exclusively lateral.

“Each type of couplet has biomechanical advantages, with lateral couplets serving to avoid limb interference, and diagonal couplets providing stability,” Shapiro says. “The use of diagonal couplets in adult humans walking quadrupedally can thus be explained on the basis of biomechanical considerations, not reverse evolution.”

Findings were reported in the journal PLOS ONE.

Shape of the hand and foot in two primate species. The fingers are represented independently (colour coded) in the primate somatosensory cortex (SI). By contrast, the representations of the toes are fused, with the exception of the big toe in humans. (Credit: Image courtesy of RIKEN)

Which came first: the dexterous hand or the agile foot?

Shape of the hand and foot in two primate species. The fingers are represented independently (colour coded) in the primate somatosensory cortex (SI). By contrast, the representations of the toes are fused, with the exception of the big toe in humans. (Credit: Image courtesy of RIKEN)

Shape of the hand and foot in two primate species. The fingers are represented independently (colour coded) in the primate somatosensory cortex (SI). By contrast, the representations of the toes are fused, with the exception of the big toe in humans. (Credit: Image courtesy of RIKEN)

A common assumption in human evolution is that our early ancestors first developed bipedal locomotion and only then did they developed dexterous hands capable of using tools, since these were free to be used no longer being required for walking. A new research by a team of Japanese scientists proved this long-standing assumption wrong, however, after they used high-end laboratory techniques to show that dexterous hands evolved before agile feet used in locomotion.

The research is particularly interesting because it combines a range of multi-disciplinary techniques and makes use of evolutionary correlations between modern humans and monkeys of today and those from the dawn of our genus. The researchers led by neurobiologist Dr. Atsushi Iriki of the RIKEN Brain Science Institute employed functional magnetic resonance imaging in humans and electrical recording from monkeys to locate the brain areas responsible for touch awareness in individual fingers and toes, called somatotopic maps. These maps showed that both humans and monkeys have discrete neural signatures for single digits in the hand and foot.

[READ MORE] Why human ancestors started walking on two legs

There’s one prominent difference between the monkey and human maps: the human big toe has its own map, while all monkey toes are combined and fused into one single map. These findings suggest that early hominids evolved dexterous fingers when they were still quadrupeds. Manual dexterity was not further expanded in monkeys, but humans gained fine finger control and a big toe to aid bipedal locomotion.

“In early quadruped hominids, finger control and tool use were feasible, while an independent adaptation involving the use of the big toe for functions like balance and walking occurred with bipedality,” the authors explained.

To support these laboratory findings, the researchers showcased the well-preserved hand and feet bones of a 4.4 million year-old skeleton of the quadruped hominid Ardipithecus ramidus, a species with hand dexterity that preceded the human-monkey lineage split. In all, the findings suggest that our early ancestors first developed hand dexterity, critical to tool use, while two-legged locomotion came after as a consequence of adaptive pressures on ancestral quadrupeds for balance control by foot digits.

“Evolution is not usually thought of as being accessible to study in the laboratory,” stated Dr. Iriki, “but our new method of using comparative brain physiology to decipher ancestral traces of adaptation may allow us to re-examine Darwin’s theories.”

The results were reported in a paper published in journal Philosophical Transactions of the Royal Society.