To understand how plant stems develop and respond to growing weight by thickening and becoming trunks until the plant itself becomes a tree, a team of researchers has produced a new study to understand more about the so-called “vertical proprioception” theory. It is a mechanism that balances the radial growth of the stem first and the stem with the weight gain of the plant.
Researchers from the University of Helsinki, the University of Cambridge and the Finnish Institute of Natural Resources have analyzed the downy birch (Betula pubescens). The researchers confirm that this tree can regulate the radial growth of the stem in relation to the weight that increases with the growth of the plant and this strength itself changes depending on the length of the stem.
In a way, the researchers’ idea is that plants somehow perceive their weight and size by thickening the stem, as Juan Alonso-Serra of the Faculty of Biological and Environmental Sciences of the University of the Finnish capital suggests.n To confirm this, the researchers analyzed the elimäki trees. It is a birch tree with genetic mutations that grows vertically for three months and then collapses following the bending of the stem. The researchers have shown that, unlike normal trees, the elimäki trees are less stable mechanically because they cannot correctly relate their width to their growing weight and this is due to the genetic mutation.
Putrescine could be very useful to combat one of the most common conditions affecting the cardiovascular system, namely atherosclerosis. Putrescine is that compound whose unmistakable smell is one of the most “bad” present in nature. We are talking about the smell emanating from rotting meat.
According to a new study conducted by researchers at the Irving Medical Center at Columbia University, it is possible to use this substance for the benefit of humans. The researchers assumed that the removal of dead cells, a process that is called “efferocytosis” and which is one of the main functions of the body, is usually compromised when the condition of atherosclerosis exists. This compromise then leads to the accumulation of plaques and aggravation of the condition itself.
By analyzing human macrophages and dying cells in the laboratory, researchers discovered the role of putrescine. While macrophages extract arginine and additional amino acids from the dead cells they assimilate, they also convert arginine into putrescine. Arginine then activates the Rac1 protein that signals macrophages to “eat” dead cells.
Researchers then carried out experiments on mice with atherosclerosis and found that the more severe mice had low stocks of putrescine because they lacked the key enzyme (arginase 1) to produce putrescine itself. By making rodents drink water with putrescine, the macrophages resumed working and the accumulation of plaques decreased.
These results open up new avenues for the possible use of putrescine even in human atherosclerotic patients or in other conditions with cranial inflammation, including Alzheimer’s disease. The study is available on Cell Metabolism.
A team of researchers at Cornell University discovered that a species of wasp Polistes fuscatus, also known as the golden paper wasp or northern paper wasp, can literally recognize the faces of other specimens of its species, a feature that the vast majority of insects cannot boast.
According to the researchers, this is one of the evolutionary characteristics that this animal has developed in order to work more and more profitably together. In fact, the wasp is one of the best known social animals and one of the most intelligent and able to cooperate.
As Michael Sheehan, professor of neurobiology and behavior, one of the authors of the study, explains, this is a surprising discovery since, at least for this species of wasp, the strongest selective pressure was the one that sees the comparison and participation and not other causes that may concern, for example, the climate, parasites or prey.
There are several vertebrate animals that can recognize the individual faces of specimens of their own species but among insects, it is something very rare. The only insects that can boast “facial recognition” are those that form common societies and see the presence of several queens.
Among the insects which see the presence of only one queen, a characteristic of the genus has not developed because evidently it is not very useful, but among those insects, like the Polistes fuscatus, for which there are also 5 or 6 regimes, the face-to-face recognition is fundamental also for the queens themselves in order to negotiate between them and direct the “trades.”
The study is available on Proceedings of the National Academy of Sciences.