Altmetric Blog

September High Five – From the Oldest Microbes to the “Newest” Giraffes

Paige Jarreau, 6th October 2016

Welcome to the Altmetric High Five! On a monthly basis, my High Five posts examine a selection of the most popular research outputs Altmetric has seen attention for that month.

This month’s most popular research papers study objects that span from tiny brain plaques, to the oldest known microbes, to the world’s tallest mammal. It’s a month of extremes, in both objects of scientific discovery as well as occasionally science news headlines.

 

 

Histopathologic image of senile plaques seen in the cerebral cortex of a person with Alzheimer's disease of presenile onset. Image credit: KGH/Wikipedia

Histopathologic image of senile plaques seen in the cerebral cortex of a person with Alzheimer’s disease of presenile onset. Image credit: KGH/Wikipedia

Paper #1. Cautious Hope for an Alzheimer’s drug

Our first High Five paper is “The antibody aducanumab reduces Aβ plaques in Alzheimer’s disease,” published in Nature on August 31, 2016.

“Alzheimer’s disease (AD) is characterized by deposition of amyloid-β (Aβ) plaques and neurofibrillary tangles in the brain, accompanied by synaptic dysfunction and neurodegeneration. Antibody-based immunotherapy against Aβ to trigger its clearance or mitigate its neurotoxicity has so far been unsuccessful. Here we report the generation of aducanumab, a human monoclonal antibody that selectively targets aggregated Aβ. In a transgenic mouse model of AD, aducanumab is shown to enter the brain, bind parenchymal Aβ, and reduce soluble and insoluble Aβ in a dose-dependent manner.” – Sevigny et al. 2016, article abstract

According to Altmetric data, over 200 news outlets including many TV news outlets covered the study, which was also tweeted over 1,000 times. Some outlets spoke of the study as a “game-changing trial” of a “plaque busting drug.” Other outlets used more cautious language. Science News headlined, “New Alzheimer’s drug shows promise in small trial.”

“An experimental drug swept sticky plaques from the brains of a small number of people with Alzheimer’s disease over the course of a year. […] The results are the most convincing evidence yet that an antibody can reduce amyloid in the brain, says Alzheimer’s researcher Rachelle Doody of Baylor College of Medicine in Houston, who was not involved in the study. Still, experts caution that the results come from 165 people, a relatively small number. The seemingly beneficial effects could disappear in larger clinical trials, which are under way.” – Laura Sanders, Science News

Twenty-seven people in the study had an adverse drug reaction involving fluid build-up in the brain, sometimes associated with headaches or more serious trouble.

“While most media reported on a ‘game-changing’ Alzheimer’s drug, neurologists knew that publication in Nature of the full results of the PRIME study of aducanumab were nothing new. The main results had been presented several times over – Including at the AAN meeting in 2015 – and, as editorialist Eric Reiman, MD, of the Banner Alzheimer’s Institute in Phoenix writes, they’ll need confirmation in an ongoing phase III trial.” – Kristina Fiore, Medpage Today

The drug trial brings hope for Alzheimer’s patients and families, but more research at a larger scale is needed.

More reading:

 

 

Original artwork: Greg Williams. Wikpedia.

Original artwork: Greg Williams. Wikpedia.

Paper #2. No “five second rule.”

Our second High Five paper is “Longer Contact Times Increase Cross-Contamination of Enterobacter aerogenes from Surfaces to Food,” published in the journal Applied and Environmental Microbiology this month. The paper tests the “five second rule” – is that piece of bread you dropped on the floor safe to eat? It depends – but definitely don’t eat a piece of watermelon dropped on the floor.

 “The popular notion of the ‘five second rule’ states food dropped on the floor for less than five seconds is ‘safe’, because bacteria need time to transfer. […] We explore this topic using four different surfaces (stainless steel, ceramic tile, wood and carpet), four different foods (watermelon, bread, bread with butter and gummy candy), four different contact times (<1, 5, 30 and 300 s), and two bacterial preparation methods. Although we show that longer contact times result in more transfer, we also show that other factors including the nature of the food and the surface are of equal or greater importance. Some transfer takes place ‘instantaneously’ at times <1 s, disproving the ‘five second rule.’” – Miranda & Schaffner, 2016

Over 200 news outlets covered the study, which also received attention from members of the public via social media. Most headlines went something like, “Science says the 5-second rule is a myth.”

“For some dropped foods, the five-second rule is about five seconds too long. Wet foods, such as watermelon, slurp up floor germs almost immediately, scientists report online September 2 in Applied and Environmental Microbiology. […] As expected, longer contact times generally meant more bacteria on the food. But the transfer depended on other factors, too. Carpet, for instance, was less likely to transfer germs than the other surfaces. Gummy candies, particularly those on carpet, stayed relatively clean. But juicy watermelon quickly picked up lots of bacteria from all surfaces in less than a second.” – Laura Sanders, Science News

But as Ian Graber-Stiehl at Slate wrote, the real question is: What bacteria are on the floor you dropped your food onto?

More reading:

 

 

Stromatolites at Shark Bay in Western Australia. Flickr/Paul Morris, CC BY

Stromatolites at Shark Bay in Western Australia. Flickr/Paul Morris, CC BY 

Paper #3. Very Old Life

Our third High Five paper is “Rapid emergence of life shown by discovery of 3,700-million-year-old microbial structures” published in Nature this month. When did life arise on Earth? Researchers from Australia and the UK report evidence from metacarbonate rock structures in Greenland that life emerged earlier than previously shown, or 3.7 billion years ago. For a sense of time, the impact that tore a piece from Earth and created the moon occurred 4.5 billion years ago.

“The presence of the ISB stromatolites demonstrates the establishment of shallow marine carbonate production with biotic CO2 sequestration by 3,700 million years ago (Ma), near the start of Earth’s sedimentary record.” – Nutman et al. 2016

Nearly 200 news outlets and a dozen blogs covered the study. Some news outlets and scientists associated the finding with implications for the search for life on Mars, because “much of the surface of Mars is thought to date from this time [e.g. 3.7 billion years ago].”

“Australian geologists say they have found ancient microbial fossils in 3.7 billion-year-old rocks in Greenland. The finding, reported in Nature last month, is some 200 million years older than previously accepted fossils.” – David Flannery, The Conversation

National Geographic headlined, “World’s Oldest Fossils Discovered Due to Climate Change.”

“These remains of ancient microbes were found in Greenland after they were exposed by melting ice—something that may become more common as the planet warms. The fossils are known as stromatolites and are the evidence of ancient water-based bacterial colonies, which cemented sediments together into distinctive layers with carbonate. Before this new discovery, the oldest known fossils were 3.48-billion-year-old stromatolites found in Western Australia.” – Brian Clark Howard, National Geographic

Other scientists debate whether the rock formations actually represent fossils.

More reading:

 

 

Image via Wikipedia.

Image via Wikipedia.

Paper #4. Your Dog Understands You. Kind Of.

Our next High Five paper is “Neural mechanisms for lexical processing in dogs,” published in Science this month. Researchers in Hungary found that dogs separately process lexical information (like when your dog knows the word “food”) and intonational information (or the tone of your voice.)

“Neural mechanisms to separately analyze and integrate word meaning and intonation in dogs suggest that this capacity can evolve in the absence of language.” – Andics et al. 2016

Over 200 news outlets covered the study. Molly Bennet writes for Slate, “A recent study suggesting dogs understand language is overblown. I know, because I asked my dog about it.”

“The study was conducted by the Family Dog Project, a research team at Hungary’s Eotvos Lorand University. Here’s what they actually did: They selected 13 dogs to put into an MRI machine and played a recording of a trainer talking to each dog. There were two variables in what the trainer said – the words (positive or neutral) and the tone of voice (positive or neutral). All the while, they scanned the dogs’ brains to see which parts lit up with activity in response to which words. As it turned out, when the trainer gave the dogs positive words, like clever and well done (apparently things people say to their dogs in Hungary), the scans showed more activity in the left hemisphere of their brains than when the dogs heard neutral words like such and yet, regardless of which tone of voice was used. Over in the right hemisphere, a known auditory region activated differently depending on whether the dogs heard praising or neutral tones (the neutral tones actually resulted in more activity – that particular brain region is more sensitive to lower pitches). But it was only when the dogs heard words of praise in a praising tone that their primary reward centers – the dopamine-pumping region of the brain that tells you when something good is happening – start going crazy.” – Molly Bennet, Slate

As Smithsonian headlined, “Dogs Know When You’re Praising Them [But] That Doesn’t Mean They Understand Human Speech.”

“It’s easy to conclude that, because dogs process verbal and nonverbal information in speech similar to the way we do, they likewise understand what they are hearing. But this would be a vast oversimplification. The study ‘shows that dogs are capable of identifying strings of phonemes that form meaningful speech commands, rather than solely relying on the command’s intonation,’ says David Reby, a psychologist at the University of Sussex whose previous behavioral studies in dogs also identified parallels in speech perception between humans and dogs. ‘It does not, however mean that dogs are capable of understanding human language.’” – Adam Hoffman, Smithsonian

 

 

 Giraffe koure niger 2006.jpg More details A West African Giraffe peeks under an Acacia tree in the tiger bush near Koure, Niger. Image credit: Roland H., via Wikipedia.

A West African Giraffe peeks under an Acacia tree in the tiger bush near Koure, Niger. Image credit: Roland H., via Wikipedia.

Paper #5. More Than One Kind of Giraffe.

Our final High Five paper is “Multi-locus Analyses Reveal Four Giraffe Species Instead of One,” published in Current Biology this month. After analyzing genetic information from 190 giraffes, traditionally thought of as belonging to a single species and multiple subspecies, Julian Fennessy and colleagues concluded that these individuals actually belong to four genetically distinct giraffe clusters or species.

“Our findings provide the most inclusive analysis of giraffe relationships to date and show that their genetic complexity has been underestimated, highlighting the need for greater conservation efforts for the world’s tallest mammal.” – Fennessy et al. 2016

Over 150 news outlets covered the study. Some headlined the study as describing four “new” giraffe species. But as biodiversity researcher and PhD candidate Morgan Jackson pointed out on Twitter, these species aren’t “new” at all. In fact, several of them had been viewed as distinct species previously, then lumped together, and now identified as separate again via DNA analysis.

“A study in the journal Current Biology recently suggested that Giraffa camelopardalis, previously considered one species with nine subspecies, are actually four separate species: the northern giraffe, the southern giraffe, the reticulated giraffe, and the Masai giraffe. ‘We’re proposing that they’re genetically different,’ says Julian Fennessy, the lead author of the study and the co-director of the Giraffe Conservation Foundation based in Namibia. The distinction highlights just how disruptive genetic analysis has been to biological classification. […] But as always, that genetic data is subject to interpretation.” – Marley Walker, Wired

More reading:

 

What did you think of our High Five papers this month? Tell us!

1 Responses to “September High Five – From the Oldest Microbes to the “Newest” Giraffes”

Innokin
October 18, 2016 at 12:00 am

Thank you for awesome blog and great service! Love the images you have chosen for this month selection <3
Always thought giraffes were more than one species btw :)

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