The top three news stories of the week, as chosen by our resident students. This week’s top stories include a hormone that can help plants retain water, intergenerational bacterial memory transfer, and an insight into kids tattling motives.

By Yonis Bare

Newly discovered hormone helps keep plants from dehydrating

We’re all aware of the importance of watering our houseplants on a regular basis but due to our busy schedules it can be difficult to remember this simple chore! Recently, a group of plant scientists at the RIKEN Center for Sustainable Resource Science (CSRS) in Japan have discovered a small peptide hormone, known as CLE25, that can help plants retain water in times when levels are scarce.

The aim of the study, published in Nature, was to find out whether any plant hormones could respond to physical (abiotic) stress. The team began to look at the effect of several CLE peptides that are synthesised at the roots of Arabidopsis plants on the levels of abscisic acid (ABA) in the leaves, which can close pores in response to drought. The data showed that only CLE25 led to increased levels of ABA in the leaves and pore closure. This result was also in line with data showing increased levels of CLE25 in the roots of plants that were subjected to drought. However, how the peptide hormone moves through the plant circulatory system remained unknown.

The detection of functional peptide hormones in living cells is very difficult due to their presence in low amounts. To circumvent this issue, the researchers used a highly sensitive mass spectrometry system coupled with a screening system that can identify the mobile peptides. Using this, the scientists were able to show that CLE25 molecules could move from the roots to the leaves, illustrating that it’s a mobile peptide hormone. Using mutant Arabidopsis plants that lacked CLE25 or ABA, the group also discovered that the BAM1/BAM3 receptors in the leaf were the link between CLE25 and ABA production.

Read the full article here

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Bacteria can pass on memory to descendants

An international group of researchers, led by scientists over at UCLA, have discovered that bacteria can pass on ‘memories’ that contain sensory knowledge from one generation of cells to the next without a central nervous system.

The group used the bacterial strain Pseudomonas aeruginosa as a model system which form biofilms in the airways of people suffering from cystic fibrosis, causing lethal infections. Similar biofilms can also form on surgical implants, which can lead to implant failure. These biofilms are made from genetically identical bacterial cells that have the capability to colonise almost all surfaces by first ‘sensing’ the surface and developing the ability to attach. To look at the bacterial cells that are involved in ‘sensing’ surfaces, the scientists used a multi-generational cell tracking method, grouped with several other data analysis methods including a signal processing technique that is more commonly used to analyse pitch in music!

Using these methods, the group were able to reveal two major events that were linked in an oscillatory pattern: cyclic AMP (cAMP) expression and type IV pili (TFP) activity, which occur within hours of each other. By ‘sensing’ and memorising this pattern, bacteria are able to become less motile and form attachments to a surface irreversibly and form a biofilm. These findings could be a major step towards understanding persistent infections caused by bacterial biofilms.

Read the full article here

 

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Snitches do not get stitches – they are for self-preservation

Throughout popular culture, the idea of a person as an ‘informer’ or ‘tattletale’ has always come with negative connotations. By the age of 3, children inform adults about broken rules that they observed, even as unaffected bystanders. However, recent research argues that tattling is a way in which children can enforce social norms and that in the long-term, it can help sustain co-operation.

A study completed by scientists in the Social Development Lab at the University of Virginia set out to investigate the function of ‘tattling’ – whether it was used in a self-serving function to remove a child from fault or to enforce norms. Interestingly, the study used hand puppets instead of adults as previous studies have shown that children were readily able to protest and tattle against puppets but are more reluctant to do so against adults, even more so in face-to-face interactions.

The test involved a role-play situation in which a child observed a puppet either causing ‘harm’ to another puppet by destroying their artwork or ‘no harm’ by destroying a different object. During the event, a third neutral puppet was included to ensure ambiguity about who committed the violation. The results showed that the 3-year-old children tattled on the puppet more when there was ‘harm’ caused in comparison to the ‘no harm’ case. The scientists concluded that the children’s tattling about third-party actions seemed to be aimed at enforcing moral norms rather than for self-serving aims.

An additional goal of this study was to also study the relationship between a child’s temperament and norm enforcement. To investigate this, the scientists looked at the children’s shyness and impulsivity and showed that shyness had a negative correlation with children’s tattling behaviour. However, the scientists concluded that more research is required to better understand the role of temperament in early norm enforcement.

Read the full article here

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