A team from the University of Iowa (USA) has found a relationship between specific species of microbiota bacteria and the severity of multiple sclerosis. Specifically, a lower ratio between the quantities of Bifidobacterium and Akkermansia was related to the disease and to a worse course of the disease, both in mice and in two cohorts of patients and people without the disease. According to the authors, who publish the results in the journal PNAS, the finding could be used to improve the diagnosis and treatment of multiple sclerosis.

A synthetic microbiome therapy, tested on mice, protects against the severe symptoms of a difficult-to-treat and potentially fatal intestinal infection in humans: Clostridioides difficile. Although inspired by the idea of human faecal transplants, the new approach does not require faecal matter. Instead, it uses fewer, but more precise, bacterial strains. The study is published in the journal Cell Host & Microbe.

According to a modelling study published in Nature Cities, the frequency of some types of fires in cities is expected to increase in the coming decades as a result of climate change. This increase would be seen in vehicle fires and in those that occur outdoors. The conclusions are based on data from more than 2,800 cities in 20 countries and could be useful for future urban planning and emergency response strategies.

The 16th meeting of the United Nations Conference on Biodiversity (COP16) in Rome has concluded with an agreement to adopt the first global plan for financing nature conservation, after three days of meetings. This meeting meant resuming the negotiations that began last October in Cali (Colombia), where the parties failed to reach an agreement on how to finance the Kunming-Montreal Global Biodiversity Framework reached at COP15, which aims to protect a third of the land and oceans by 2030.

Research has analyzed how extreme heat influences the biological age of elderly populations, specifically in the United States. The study, published in Science Advances, used blood samples from more than 3,600 adults with an average age of 68 collected between 2010 and 2016. The team compared epigenetic aging trends with the number of days of extreme heat in the participants' places of residence. The models showed that more days of heat or long-term heat — over a period of one to six years — increased the biological age of the participants by more than two years.

The Atlantic Ocean's main current system - the AMOC - could weaken without collapsing this century, according to modeling published in Nature. This finding contradicts earlier studies that predicted the collapse of the AMOC around 2050. The research uses models that include extreme changes in greenhouse gas concentrations and freshwater levels in the North Atlantic. This system of ocean currents is involved in regulating global temperatures.

The red colour of Mars corresponds to a type of ferrihydrite that is the dominant form of iron oxide in Martian dust, although previous studies have attributed it to anhydrous haematite. The persistence of ferrihydrite, whose formation requires water, suggests that it formed during a cold, wet period, followed by a transition to the planet's current arid environment. The result, based on ESA and NASA space data and new laboratory experiments, is published in Nature Communications.

People with dementia who are prescribed a specific type of antidepressant experience a faster cognitive decline than people who do not use these drugs, according to a study published in BMC Medicine. In particular, prescriptions for higher doses of selective serotonin reuptake inhibitors (SSRIs), a type of antidepressant, were associated with a higher risk of severe dementia, fractures and mortality. The analysis includes data from more than 18,000 patients from a Swedish database between 2007 and 2018.

Peto´s paradox is the lack of observed relationship between the size of an animal and the prevalence of cancer, despite the fact that the greater number of cells and divisions as they get larger should increase the likelihood of cancer. A new study disproves this paradox by finding that, at least in terrestrial vertebrates, larger species do develop more cases of cancer. In quite a few of them, however, the increase is less than would be expected, suggesting that they have evolved anticancer mechanisms that remain worth studying. The results are published in the journal PNAS.  

One study suggests that conservation efforts are concentrated around a small number of charismatic species, such as elephants. However, there are undervalued species, such as fungi, plants and invertebrates, that are critical to the functioning of ecosystems. The research, published in the journal PNAS, analysed more than 14,000 conservation projects spanning a 25-year period - from 1992 to 2016. Of the nearly $2 billion allocated by the projects, 83% went to vertebrates. Plants and invertebrates each received 6.6% of the funding, while fungi and algae received less than 0.2%.