Mytones in bacteria have a strange way of packing chromosomes and controlling gene expression: the case of B. bacteriovorus
Some bacteria have a bizarre way of packaging chromosomes and regulating gene expression: they use proteins that weren’t thought to exist in bacteria at all. The histones appear to coat the regions of the chromosomes in two different species. This is a marked difference from histones’ function in eukaryotes (which includes animals, plants and fungi), in which the proteins form a spool for DNA to wind around. The research team found a few histone-like factors in about 2% of the genomes. For now, it’s unclear what the histones might be doing, and how their unusual mode of action might help the bacteria to survive.
The researchers were able to survey thousands of bacterium’s genomes. The finding of histone-like proteins in roughly 2% of the genomes suggests there will be many other systems to study. “People got excited and said ‘oh, bacteria weren’t supposed to have histones’,” says Warnecke. “But if you work on microbial evolution, you know that if you look hard enough, you’ll find some.”
There are questions for synthetic biologists about the lack of diversity, as well as ways to control the expression of genes. The composition of the human genome and how it is made is very similar to that in otheryotes, and then you start to wonder if that is a frozen accident. Can we build systems in a different way or do histones have something to do with it?
For now, researchers can only speculate as to what the histones might be doing, and how their unusual mode of action might help the bacteria survive. For B. bacteriovorus, the histones could be protecting the DNA from picking up stray pieces of the fragmented genomes of its prey, says Warnecke.
The bacterium is also known for having tightly packed DNA during its free-swimming phase, before it infects its prey, notes Géraldine Laloux, a microbiologist at the Catholic University of Louvain in Belgium. “We have been wondering what drives this very strong compaction and how it de-compacts,” says Laloux. New insights into this could be brought by the unique way of binding the DNA.
Climate models show that driving is a bad thing: why people shouldn’t drive in highly populated areas when people can’t think objectively
The amount of antibiotics used in animal farming is underestimated in official reports. Researchers collated figures from sources such as farm surveys and drug sales, because “the majority of data on antibiotic use in the world is unusable”, according to epidemiologist Thomas Van Boeckel. Africa’s usage of antibiotics is more than double that reported by the World Organization for Animal Health, and it is 50% higher than reported in Asia, according to data from 229 countries. The use of antibiotics in animals is projected to grow. There are efforts to curtail agricultural antibiotics use, which could drive drug-resistant infections in humans.
A team of environmental scientists has a plan to end a long-running dispute between Egypt, Ethiopia and Sudan over Africa’s largest hydroelectric dam. Since construction began in 2011, the countries have been trying and failing to resolve concerns including the speed of completing the project and the volume of water that will be released to drive the electricity-generating turbines. Researchers used climate models and artificial intelligence to create scenarios for how the dam could operate to maximize economic benefits while adapting to the effects of climate change. The solution offered by the plan is a win–win solution for the countries.
People are more likely to say that the negative effects of driving are related to pollution than they are to say that the same thing in other areas of life. In a survey of 2,157 drivers and non-drivers in the United Kingdom, roughly half were asked to rate a statement about cars. The others were given an almost identical sentence about another issue. It was 75% of people that said people shouldn’t smoke in highly populated areas where other people have to breathe in the fumes. However, only 25% thought people should drive in highly populated areas. The researchers believe that this negative attitude about cars hurts our ability to think objectively.
Living Without Sleep: The Case of Barbara Rae-Venter, a Serial Killer and Bioengineering Investigating Extreme Crimes
Barbara Rae-Venter, a former biologist and patent attorney, stumbled into an intense post-retirement hobby: using consumer DNA databases to solve mysteries. In 2018, she was key to identifying a serial murderer known as the Golden State Killer by connecting crime-scene DNA to genetic information that people had innocently uploaded to GEDmatch. Rae-Venter is the author of a new book called I Know Who You Are. But the book disappoints when examining the ethical quandaries that ensnare the field, writes Nature features editor Brendan Maher in his review.
Acting out vivid dreams — for example by flailing, kicking or jumping out of bed — can be a harbinger of neurodegenerative diseases. The REM sleep behavior disorder, which occurs during the rapid eye movement (REM) sleep phase, seems to be linked to the development of toxic clumps in the brain. Actor and science-communication advocate Alan Alda, who starred in the television series MAS*H, was diagnosed with Parkinson’s disease after reading about the link and noticing the symptom in himself. People with motor problems can still move or shout when they are asleep if they are awake.
Global warming beyond the Paris agreement goal of 1.5 C above pre-industrial levels is seen as spelling an inevitable global disaster. Yet the figure doesn’t represent a planetary threshold or ecological tipping point, argue climate sociologists Béatrice Cointe and Hélène Guillemot in a history of the iconic target. It emerged from decades of diplomatic negotiations, and remains a powerful tool to spur governments, industries and individuals into action. The target seems to be increasingly unreachable, but framing it as a point of no return can lead to paralysis and apathy, notes environmental writer Emma Marris.