microbiology

Two articles published in the journal Scientific Reports explore the survival capacity of microorganisms and plants in imitations of lunar and Martian soils. In the first, the team succeeded in cultivating chickpea plants in a lunar soil simulant — lunar regolith — treated with arbuscular mycorrhizal fungi and worm compost. In the second article, microbial growth was investigated in a Martian soil simulant with different water proportions and under pressure and temperature conditions similar to those on Earth. At a water level comparable to that on Mars, an atmospheric humidity of 34 %, microbial mass increased, although it fell back to zero after 60 days. “These findings extend the known physicochemical limits of life in solid substrates and provide new insight into the potential habitability of hyper-arid extraterrestrial environments,” the authors say.

In the ephemeral pools along the coasts of the Caribbean island of Curaçao lives Choanoeca flexa, a tiny unicellular aquatic organism belonging to the choanoflagellates, important for being close relatives of animals. As the pools evaporate and refill, C. flexa can switch between unicellular and multicellular forms in three different ways: by division, by aggregation, or by combining both, mechanisms that were previously thought to be mutually exclusive. The discovery, published today in Nature, may challenge current understanding of the origins of multicellular life.

Infections caused by the fungus Candidozyma auris—formerly known as Candida auris—continue to rise, warns a report by the European Centre for Disease Prevention and Control (ECDC). Spain reported 1,807 of the 4,012 cases in 36 European countries between 2013 and 2023, the highest number ahead of Greece (852 cases) and Italy (712), according to the survey. This microorganism spreads particularly in hospitals, causing infections that are often resistant to existing drugs.

The cyanobacterium Prochlorococcus, the smallest and most abundant photosynthetic organism on Earth, is an important producer of oxygen and is crucial to marine ecosystems. A team from the United States has collected data from ships sailing the Pacific Ocean over a ten-year period and concluded that these cyanobacteria could experience population declines of between 17% and 51% in tropical oceans by the year 2100, depending on the warming scenario. The results, which are the product of modeling work, are published in the journal Nature Microbiology and indicate that this microorganism is more vulnerable to climate change than previously thought.

The research article A bacterium that can grow by using arsenic instead of phosphorus was one of the big science stories because it discussed the possibility of arsenic-based life. However, it has been the subject of criticism until now. After nearly 15 years of debate and failed attempts by other groups to replicate the findings, Science has now decided to retract the article, despite finding no evidence of fraud or misconduct on the part of the authors, who disagree with the decision.

An international study has warned of the potential risks of widespread use of faecal microbiota transplantation without taking into account the region of the intestine where the transferred microbes arrive. The experiment, conducted on mice and human tissue samples, showed that the microbes from the transplant—mostly anaerobic microbes from the colon—colonised the small intestine, persisted there for months and modified that new environment, causing changes in the host's metabolism. According to the authors, whose study is published in the journal Cell, this may have long-lasting and unforeseen consequences, as well as imbalances in the intestinal ecosystem of patients.

A study published today in Nature with the participation of the CNIO points to the bacterial toxin colibactin, produced by some strains of Escherichia coli, as a possible culprit in the increase in early-onset colorectal cancer. The study shows that exposure to the toxin during early childhood leaves a genetic signature in colon cells and demonstrates a substantial increase in these mutations in cases of colorectal cancer in people under 50.

A team from Canada and the United States has found a candidate to form part of a new class of antibiotics, lariocidin. This could be effective against multi-resistant bacteria. The finding is published in the journal Nature.

A CNIC research team has identified a population of skin neutrophils that reinforce the physical protection of the tissue against infection. These immune cells are known for their microbicidal role, and the study published in Nature reveals that they also produce an extracellular matrix that reinforces the physical barrier of the skin.

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.