Connect with us

TOP SCEINCE

Some mice may owe their monogamy to a newly evolved type of cell

Published

on

Some mice may owe their monogamy to a newly evolved type of cell


What makes the oldfield mouse steadfastly monogamous throughout its life while its closest rodent relatives are promiscuous? The answer may be a previously unknown hormone-generating cell, according to a new study published online today in Nature from scientists at Columbia’s Zuckerman Institute.

“The hormone from these cells was actually first discovered in humans many decades ago, but nobody really knew what it did,” said Andrés Bendesky, MD, PhD, a principal investigator at Columbia’s Zuckerman Institute. “We’ve discovered that it can promote nurturing in mice, which gives us an idea of what it might be doing in humans.”

The new study investigated two species of mice. One is the most abundant mammal in North America — the deer mouse (Peromyscus maniculatus), which ranges from Alaska to Central America. The other, the oldfield mouse (Peromyscus polionotus), lives in Florida and Georgia, and is a bit smaller, weighing in at roughly 13 grams compared with the deer mouse’s 18 grams.

More than 100 years of previous research has shown that the mice species behave in strikingly different ways. Whereas the deer mouse is promiscuous — even a single litter of pups can have four different fathers — the oldfield mouse mates for life.

However, prior work also suggested these species are evolutionary siblings, based on similarities in their skulls, teeth and other anatomical features, as well as their genetics. To find out why these close mouse relatives behave so differently, the scientists examined their adrenal glands.

“This pair of organs, located in the abdomen, produces many hormones important for behavior,” said Dr. Bendesky, who is also an assistant professor of ecology, evolution and environmental biology at Columbia University. “These include stress hormones such as adrenaline, but also a number of sex hormones.”

The adrenal glands of these mice proved startlingly different in size. In adults, the adrenals of the monogamous mice are roughly six times heavier than those of promiscuous mice (after adjusting for differences in the body weight between the species).

“This extraordinary difference in the size of an internal organ between such closely related species is unprecedented,” Dr. Bendesky said.

Genetic analysis of the adrenal cells revealed that one gene, Akr1c18, saw far more activity in the monogamous mice than in the promiscuous rodents. The enzyme this gene encodes helps create a little-studied hormone known as 20⍺-OHP, which is also found in humans and other mammals.

The researchers observed that increasing 20⍺-OHP hormone boosted nurturing behavior in both mouse species. For instance, 17 percent of the promiscuous mice who were given the hormone groomed their pups and brought them back to their nests, whereas none behaved this way if not given the hormone.

“This marks the first time we found anything that could increase parental care in the promiscuous group,” Dr. Bendesky said.

Normally these glands are divided into three zones. But the scientists discovered that the adrenals of the monogamous mice possessed a fourth zone.

“We called this the zona inaudita, which is Latin for ‘previously unheard-of zone,’ because no one has ever observed this type of cell in another animal,” said Natalie Niepoth, PhD, a co-first author on the study who is now a senior scientist at Regeneron.

In zona inaudita cells, the researchers found that 194 genes, including Akr1c18, were far more active compared with the same genes in other adrenal cells. Their analyses also identified key genes underlying the development and function of the zona inaudita in the oldfield mice.

This completely unheard-of structure apparently evolved rapidly. Genetic mutations accumulate in genomes at roughly predictable rates over time. By measuring the number of mutations distinguishing these species, the scientists estimated this novel cell type evolved within the past 20,000 years, “which is just an eyeblink when it comes to evolution,” Dr. Bendesky said.

Much remains uncertain about what drives the evolution of monogamous behavior. One argument suggests that monogamy can increase the chances that parents will cooperate to care for their offspring, since fathers are more confident the young are theirs. This kind of teamwork can improve the chances that the progeny will survive, especially when resources are limited, Dr. Bendesky said. The newly found adrenal cells promote parenting behavior typical of monogamy, the researchers noted.

The new findings could provide insights when it comes to parenting behavior and challenges in humans, Dr. Niepoth suggested. For example, in mice, 20⍺-OHP is often converted into a compound very similar to the molecule allopregnanolone, which naturally occurs in humans and has been approved by the FDA as a drug to help treat the postpartum depression that people often experience after childbirth, Dr. Bendesky said.

“I hope that our study motivates further investigation into the link between 20⍺-OHP and parenting in humans,” saidJennifer R. Merritt, PhD, a co-first author on the study and postdoctoral researcher in the Bendesky lab.. “We have so much to learn about the role this hormone plays in human parental behavior.”



Source link

Continue Reading
Click to comment

Leave a Reply

TOP SCEINCE

Orchids support seedlings through ‘parental nurture’ via shared underground fungal networks

Published

on

By

Orchids support seedlings through ‘parental nurture’ via shared underground fungal networks


The Common Spotted Orchid (Dactylorhiza fuchsii) is found all over the UK. These orchids produce tiny seeds that can be carried anywhere by the wind, yet they often appear in clumps with small seedlings growing near mature plants. This phenomenon has puzzled ecologists since Darwin’s time, with the exact reason remaining a mystery.

A new study, led by researchers from the University of Sheffield in collaboration with The University of Manchester, provides the first evidence that early stage orchid seedlings germinate and thrive near to adult plants due to a kind of parental nurture using underground fungal networks.

Scientists investigated the idea that fungal networks, known as mycorrhizal networks, act as a direct pathway for established orchid plants to share recently produced sugars with developing seedlings.

Professor Katie Field, co-author of the study and Professor of Plant-Soil Processes at the University of Sheffield’s School of Biosciences, said: “Our results support the idea that some orchids engage in a form of ‘parental nurture’ with their seedlings. By supplying early stage seedlings with essential nutrients via shared fungal connections, the parent orchids give the seedlings an advantage over neighbouring plants that are competing for the same resources.

“This finding is exciting because why these orchids are often found in clumps, despite their seeds being wind dispersed, has been a puzzle for hundreds of years.”

The study focused on the Common Spotted Orchid and its fungal partner, Ceratobasidium cornigerum. Researchers created a system where mature, green orchids were connected to developing, chlorophyll-free seedlings through a fungal network grown on agar.

The mature plants were then exposed to a special form of carbon dioxide that could be tracked within the system.

Here’s how it worked:

  • Green orchid plants were connected to developing seedlings through the fungal network.
  • The green plants were then exposed to a special form of carbon dioxide that could be tracked within the system.
  • After a period of time, the researchers analysed both the seedlings and the fungal network to see where the labelled carbon ended up.

The results were clear, the seedlings were accumulating the labelled carbon, indicating they were being supported by the adult plants. By tracking the movement of carbon, the study showed that the mature orchids were indeed sharing their recently produced sugars with the seedlings through the fungal network.

Sir David Read, Emeritus Professor of Plant Sciences from the University of Sheffield and lead author of the study, said: “Whereas the seeds of most plants, for example legumes (peas, beans) and grasses (rice, corn, wheat) are fully provisioned with food reserves by their parent plants, the so-called dust seeds of orchids receive insufficient reserves from the parents to develop on their own.

“They are instead produced in their millions by each individual parent orchid plant from which they are dispersed, by wind, to the surrounding environment. Even Charles Darwin was puzzled by this strategy, suggesting that while it should enable the seeds of an individual orchid plant to be so widely distributed that within a few years it could colonise the whole world. He observed that their failure to do so ‘could not be understood at this time’.

“What is now revealed is that the belowground development of these essentially reserve-free seeds can be supported by photosynthetically produced sugars that are transported to them from mature plants growing above ground through a shared mycelium of symbiotic fungi.”

Results of the study, published in New Phytologist, show the amount of carbon transferred seemed to depend on the environment. When the fungus had access to a richer food source (oatmeal agar), less carbon was transferred to the seedling. This suggests that the strength of the demand from the seedlings may influence the flow of nutrients through the network.

This research has important implications for understanding orchid ecology and conservation efforts. By recognising the importance of fungal connections, scientists can develop better strategies for protecting these unique and often threatened plants.

Next steps are to research this theory in the natural habitat that the orchids are found in and to look at whether this applies to other species.



Source link

Continue Reading

TOP SCEINCE

Bird flu: Diverse range of vaccines platforms ‘crucial’ for enhancing human pandemic preparedness

Published

on

By

Bird flu: Diverse range of vaccines platforms ‘crucial’ for enhancing human pandemic preparedness


Vaccination remains the most effective strategy for avian influenza prevention and control in humans, despite varying vaccine efficacy across strains.

That’s according to the authors of a new review which delves into existing research into bird flu vaccines for humans.

Published in the peer-reviewed journal Human Vaccines & Immunotherapeutics, the results of the paper are particularly timely following news last week (Wednesday 22nd May) that the bird flu strain H5N1 had once again, for a second time, jumped from cattle in America to a human — prompting fears of subsequent human-to-human infection, with possible critical consequences.

Instances of the avian influenza were first recognized in US cattle in March. Since then, this strain has mainly spread from cow-to-cow and scientists have discovered very high levels of virus in raw milk (pasteurized milk is safe, having shown viral RNA but not infectious virus). To-date two people, however, are known to have contracted the bird flu virus. Both patients — US farmers — only reported eye symptoms and with treatment they made a full recovery.

Following tests on the first human instance, it was seen that the strain had mutated to be better adapted to mammalian cells, but as long as that human didn’t pass it onto another person it likely stopped the spread at that point. With the second case, the CDC has released a statement to say it has been monitoring influenza surveillance systems intently, especially in impacted states. “There has been no sign of unusual influenza activity in people, including in syndromic surveillance,” they report.

The concern now, though, is that if H5N1 continues to be given the environment in which to mutate (such as in close quarter cattle farms) — and this continues long enough — it has the potential to find a combination that will easily spread to humans.

The results of this new research, carried out by a team at the University of Georgia, USA, suggests vaccines still remain our “primary defense” against potential spread of avian influenzas such as the H5N1 and others assessed.

“The H5N1, H7N9, and H9N2 subtypes of avian influenza virus pose a dual threat, not only causing significant economic losses to the global poultry industry but also presenting a pressing public health concern due to documented spillover events and human cases,” explains lead author Flavio Cargnin Faccin, who alongside his mentor Dr. Daniel Perez of the University of Georgia, USA, analyzed the current landscape of research into human vaccines for these bird flus.

“This deep delve into the landscape of avian influenza vaccines for humans shows vaccination remains the primary defense against the spread of these viruses.”

The team examined studies of vaccines tested in mice, ferrets, non-human primates, and clinical trials of bird flu vaccines in humans, and assessed both established platforms and promising new directions.

The review carried out suggests inactivated vaccines are a safe and affordable option that primarily activate humoral immunity — the part of our immune system that produces antibodies.

Live attenuated influenza vaccines (LAIVs) are known to induce a wider immune response than inactivated vaccines, activating not only antibody production but also mucosal and cellular defenses. In this review, the authors suggest this broader response may offer greater protection, though, the authors suggest further research is needed to fully understand and harness its potential benefits for both human and agricultural applications.

The review also examined alternatives, such as virus-like particle (VLP) vaccines and messenger RNA (mRNA) vaccines, that have emerged more recently. Although VLP vaccines for bird flu have limited clinical trial data in humans, results from studies in mice and ferrets showed promise, the authors found. mRNA vaccines against H5N1 and H7N9 bird flu subtypes also generated a rapid and strong immune response in mice and ferrets, and, while data in humans is scarce, results from a phase 1 study of an H7N9 mRNA vaccine in healthy humans were “encouraging.”

Overall, the team suggests “exploring and employing a diverse range of vaccine platforms,” will be “crucial for enhancing pandemic preparedness and mitigating the threat of avian influenza viruses.”



Source link

Continue Reading

TOP SCEINCE

When should you neuter or spay your dog?

Published

on

By

When should you neuter or spay your dog?


Researchers at the University of California, Davis, have updated their guidelines on when to neuter 40 popular dog varieties by breed and sex. Their recent paper in Frontiers in Veterinary Science adds five breeds to a line of research that began in 2013 with a study that suggested that early neutering of golden retrievers puts them at increased risk of joint diseases and certain cancers.

That initial study set off a flurry of debate about the best age to neuter other popular breeds. Professors Lynette and Benjamin Hart of the School of Veterinary Medicine, the study’s lead authors, set out to add more breed studies by examining more than a decade of data from thousands of dogs treated at the UC Davis veterinary hospital. Their goal was to provide owners with more information to make the best decision for their animals.

They specifically looked at the correlation between neutering or spaying a dog before 1 year of age and a dog’s risk of developing certain cancers. These include cancers of the lymph nodes, bones, blood vessels or mast cell tumors for some breeds; and joint disorders such as hip or elbow dysplasia, or cranial cruciate ligament tears. Joint disorders and cancers are of particular interest because neutering removes male and female sex hormones that play key roles in important body processes such as closure of bone growth plates.

For the most recent study, they focused on German short/wirehaired pointer, mastiff, Newfoundland, Rhodesian ridgeback and Siberian husky. Data was collected from the UC Davis veterinary hospital’s records that included more than 200 cases for each of these five breeds weighing more than 20 kg (or 44 pounds), spanning January 2000 through December 2020.

The Harts said their updated guidelines emphasize the importance of personalized decisions regarding the neutering of dogs, considering the dog’s breed, sex and context. A table representing guidelines reflecting the research findings for all 40 breeds that have been studied, including the five new breeds, can be found here.

Health risks different among breeds

“It’s always complicated to consider an alternate paradigm,” said Professor Lynette Hart. “This is a shift from a long-standing model of early spay/neuter practices in the U.S. and much of Europe to neuter by 6 months of age, but important to consider as we see the connections between gonadal hormone withdrawal from early spay/neuter and potential health concerns.”

The study found major differences among these breeds for developing joint disorders and cancers when neutered early. Male and female pointer breeds had elevated joint disorders and increased cancers; male mastiff breeds had increased cranial cruciate ligament tears and lymphoma; female Newfoundland breeds had heightened risks for joint disorders; female Ridgeback breeds had heightened risks for mast cell tumors with very early neutering; and Siberian huskies showed no significant effects on joint disorders or cancers.

“We’re invested in making contributions to people’s relationship with their animals,” said Benjamin Hart, distinguished professor emeritus. “This guidance provides information and options for veterinarians to give pet owners, who should have the final decision-making role for the health and well-being of their animal.”

Their combined research studies will soon be available with others in the open access journal, Frontiers of Veterinary Science, as a free e-book, Effective Options Regarding Spay or Neuter of Dogs.

Other researchers on this UC Davis study include: Abigail Thigpen, Maya Lee, Miya Babchuk, Jenna Lee, Megan Ho, Sara Clarkson and Juliann Chou with the School of Veterinary Medicine; and Neil Willits with the Department of Statistics.

The research received a small amount of funding from the Center for Companion Animal Health, but was primarily conducted by the above authors as volunteers.



Source link

Continue Reading

Trending

Copyright © 2017 Zox News Theme. Theme by MVP Themes, powered by WordPress.