News from the Science World
Study on Social Isolation during Childhood on Mice
Source: The Mount Sinai Hospital / Mount Sinai School of Medicine
ScienceDaily Summary: „Researchers have identified specific sub-populations of brain cells in the prefrontal cortex, a key part of the brain that regulates social behavior, that are required for normal sociability in adulthood and are profoundly vulnerable to juvenile social isolation in mice.“
Method of Research
A research team from the Icahn School of Medicine at Mount Sinai studied social isolation on juvenile mice, in order to better understand the mental health consequences of social isolation and loneliness.
- A specific sub-population of brain cells in the prefrontal cortex (which plays an important role in regulating social behaviour) has been indentified
- The study uncovered a previously unrecognized role of the medial prefrontal cortex neurons
- If replicated in humans, it could lead to treatments for psychiatric disorders connected to isolation
- In male mice, two weeks of isolation immediately followed by weaning led to „a failure to activate medial prefrontal cortex neurons projecting to the *paraventricular thalamus during social exposure in adulthood“ (*paraventricular thalamus: area of the brain which relays signals to various components of the brain’s reward circuitry)
Despite the increased connectivity through digital platforms, young people in our society are feeling a growing sense of isolation. Additionally, the Covid-19 pandemic and the subsequent implementation of social distancing and school closers by many countries, mangified the need to understand the mental health consequences of social isolation and loneliness.
Research in the past has shown that social isolation, especially during childhood, is detrimental to adult brain function and behaviour across mammalian species; however, the underlying neural circuit mechanisms have remained poorly understood.
In the study at hand, optogenetics (use of light to stimulate particular neurons) and chemogenetics (non-invasive chemical control over cell populations) were used to quickly increase social interaction in these mice.
As Dr. Morishita is quoted in the article: „We checked the presence of social behavior deficits just prior to stimulation and when we checked the behavior while the stimulation was ongoing, we found that the social behavior deficits were reversed.“
The identification of these specific prefrontal neurons will also „point toward therapeutic targets for the improvement of social behavior deficits shared across a range of psychiatric disorders“.
Many Animal Species may be vulnerable to SARS-Cov-2 infection, according to a genomic analysis
Source: University of California – Davis
ScienceDaily Summary: „Analysis of ACE2, the main receptor that SARS-CoV-2 uses to bind and enter cells, across 410 vertebrate species reveals that many are potentially susceptible to infection by the novel coronavirus. They include a number of endangered and threatened species, notably apes and old world primates. The study could also reveal potential intermediate hosts and animal models for the virus.“
Method of Research
Genomic analysis was used by an international team of researchers to compare the main cellular receptor for the virus in humans – ACE2 = angiotensin converting enzyme-2 – to 410 different species of vertebrates, including birds, fish, amphibians, reptiles and mammals.
Normally, ACE2 is found on various types of of cells and tissues, including epithelial cells* in the nose, mouth and lungs. 25 amino acids of the ACE2 protein are important for the virus to bind and gain entry into cells (in humans).
„The researchers used these 25 amino acid sequences of the ACE2 protein, and modeling of its predicted protein structure together with the SARS-CoV-2 spike protein, to evaluate how many of these amino acids are found in the ACE2 protein of the different species.“
*More information about epithelial cells (what they are, where they are, and how they work) can be read here
- Highest risk of contracting SARS-CoV-2 via ACE2: animals with all 25 amino acid residues matching the human protein
- Risk is predicted to decrease the more the species‘ ACE2 binding residues differ from humans
- ~ 40% of the species potentially susceptible to SARS-CoV-2 are classified as „threatened“ by the International Union for Conservation of Nature (and they may be more vulnerable to human-to-animal transmission)
In the article, Harris Lewin (lead author of the study and a distinguished professor of evolution and ecology at UC Davis) told Science Daily: „The data provide an important starting point for identifying vulnerable and threatened animal populations at risk of SARS-CoV-2 infection. We hope it inspires practices that protect both animal and human health during the pandemic.“
It’s also important to mention that endangered species are predicted to be at risk, among them are:
Very High Risk: the Western lowland gorilla, Sumatran orangutan and Northern white-cheeked gibbon Other animals flagged as high risk are marine mammals such as gray whales and bottlenose dolphins, as well as Chinese hamsters.
Medium Risk: domestic animals such as cats, cattle and sheep.
Low Risk: dogs, horses and pigs.
However, it is yet unknown how it relates to infection and disease risk (reminder: it is about risk for ACE2 binding). As the article points out: How this relates to infection and disease risk needs to be determined by future studies, but for those species that have known infectivity data, the correlation is high.
For more information, I will link to the article, but remember as it is stated there:
„The authors urge caution against overinterpreting the predicted animal risks based on the computational results, noting the actual risks can only be confirmed with additional experimental data. The list of animals can be found here.“
High-fidelity record of Earth’s climate history puts current changes in context
Source: University of California – Santa Cruz
ScienceDaily Summary: „Scientists have compiled a continuous, high-fidelity record of variations in Earth’s climate extending 66 million years into the past. The record reveals four distinctive climate states, which the researchers dubbed Hothouse, Warmhouse, Coolhouse, and Icehouse. These major climate states persisted for millions and sometimes tens of millions of years, and within each one the climate shows rhythmic variations corresponding to changes in Earth’s orbit around the sun.“
Method of Research
The findings, as outlined in the article, were the result of decades of work and a large international collaboration.
While not the exact method is explained, which would probably be too long due to the great length of the research, the article mentions that „[c]ritical to compiling the new climate record“ were the high-quality sediment cores from deep ocean basins. The International Ocean Drilling Program (ODP, later the Integrated Ocean Drilling Program, IODP, succeeded in 2013 by the International Ocean Discovery Program) was responsible for getting these sediments. Information was able to be gathered from the sediments by analyzing them, as the article points out: „Signatures of past climates are recorded in the shells of microscopic plankton (called foraminifera) preserved in the seafloor sediments.“
After analyzing it, the researchers developed an „astrochronology“ by matching the climate variations recorded in sediment layers with variations in Earth’s orbit (known as Milankovitch cycles)1. On this data, the researchers then reconstructed past climates and were able to see long-term coarse changes as well.
- Discovery of 4 different climate states: Hothouse, Warmhouse, Coolhouse, and Icehouse
- Past 3 million years: Icehouse (during this time humanity evolved)
- Eocene epoch (56 million years ago to 34 million years ago): In the early Eocene there were no polar ice caps, average global temperature: 9-14 °C higher than today, presumably the „Hothouse“ state before changing to „Warmhouse“
- Climate record of the past 66 million years reconstructed -> finding: climate’s response to orbital variations depends on factors „such as greenhouse gas levels and the extent of polar ice sheets“
- Human activities and greenhouse gas emissiosn are driving the planet toward the Warmhouse and Hothouse state (not seen since the end of the Eocene epoch)
To quote a paragraph of the article: „Most of the major climate transitions in the past 66 million years have been associated with changes in greenhouse gas levels. Zachos has done extensive research on the Paleocene-Eocene Thermal Maximum (PETM), for example, showing that this episode of rapid global warming, which drove the climate into a Hothouse state, was associated with a massive release of carbon into the atmosphere. Similarly, in the late Eocene, as atmospheric carbon dioxide levels were dropping, ice sheets began to form in Antarctica and the climate transitioned to a Coolhouse state.“
Lastly, Zachos mentions IPCC projections in the year 2300, if nothing is done to combat climate change: „The IPCC projections for 2300 in the ‚business-as-usual‘ scenario will potentially bring global temperature to a level the planet has not seen in 50 million years.“
1 from the article 1:1 taken over
Due to the importance, and still my lack of fluently speaking English, a lot of it has only been midly changed or quoted directly from it. I sincerely hope that I haven’t missed any findings, otherwise let me know. As always, I’ll link to the original article to read for yourself and ensure that you get all of the information.