Naked mole rats are proving valuable in battling brain diseases like strokes. These fleshy, hairless creatures are native to African deserts where colonies of up to 300 rats are couped up in underground burrows; oxygen is a luxury for them.
The air they breathe is mostly foul and could lead to irreversible brain damage. Yet their brains were found to withstand the deficit for periods exceeding half an hour—impossible for other mammals. Mammals can survive an oxygen-deficient environment only in the womb. The mole rats are an exception as they retain the ability even in their adulthood. The next step is to learn how their brains do it. Neuroreport, December 9
Cyanobacteria, the photosynthesizing bacteria, are better biofuel sources than plants. But extracting the high-energy fats from them is difficult because they have a nearly impenetrable cell wall that is designed to protect them from harsh conditions. A team placed a host of genes, from its enemy the bacteriophage, into the bacteria. The genes triggered a self-destructing pattern making the bacteria burst like balloons and release the stored products. These bacteria also form the unrelenting pond scum. Getting them to self-destruct might have hope for the water bodies too. Proceedings of the National Academy of Sciences, December 7
The debate about how dinosuars evolved and when they migrated across the super-continent Panagea reached its conclusion with the discovery of the 213 million-years-old fossil of Tawa hallae in USA’s New Mexico:
* Dinosaurs originated and evolved under three lineages: the herbivorous saurpods, ornithiscians and the carnivorous theropods.
* In the 1960s, a fossil named Herrerasaurus was discovered alongside the fossils of a sauropod and an ornithiscian in South America.
* Herrerasaurus was a carnivore with theropod features but some of its attributes were atypical of a theropod thus sparking a debate on its origin.
* Tawa is the missing link with all the theropod and Herrerasaurus features making the Herrerasaurus a definite theropod.
* Tawa’s discovery proves that dinosaurs originated and rapidly evolved into the three main lineages in South America about 230 million years ago.
* Later when they migrated to North America, only the carnivores survived its climate and went on to spawn birds. Science, December 10
Evolution of battery
Making batteries out of paper is increasingly attracting scientists. Here’s the latest addition to the list: A researcher coated ordinary paper with a solution comprising carbon nanotubes and silver nanowires. The two components acted as the electrodes for a battery which could be charged 40,000 times. This is much more than what an efficient lithium battery can endure. Being made of paper, it is ultra-light and flexible. The battery stays intact even if the paper is crumpled or something spills on it accidentally. Plastic was considered as an option earlier but the nanotubes adheres better to paper. Proceedings of the National Academy of Sciences, December 10
Fooled by the look-alike
Statistics on the white marlin populations are not as accurate because the fish has a look-alike—the roundscale spearfish. A new report says that the roundscale spearfish, discovered three years ago, actually makes up one-third of the fish caught as the white marlin. This calls for reassessment of the white marlin population sizes. An elongated, large-jawed fish, the white marlin is sought after by anglers in prize-winning tournaments worth millions of dollars. It is also caught as bycatch by commercial fisheries and its populations are declining. Two petitions were sent to the US Endangered Species Protection Act in 2002 and 2007 for the fish to get a conservation status. They are still pending.
Endangered Species Research, December 10
Honey bees release a deadly odour to cut short their sisters’ lifespan—and all for food. Bees live on body reserves of proteins and lipids called vitellogenin which also helps them tide over unfavourable conditions like shortage of food during winter. Worker bees have large reserves in their body because this is the food that is fed to young larvae; the lifespan of worker bees is about 3-6 weeks in summers and 20 weeks in winters. Scientists found that the brood releases a foul-smelling pheromone which the worker bees respond to by quickly transporting the stored fat via blood to the mouth where they are converted into a jelly, the brood feed. This cuts down the workers’ lifespan even further and sometimes entire colonies collapse within 200 days. Scientists are wondering if this could be a reason for the notorious colony collpase disorder.
The Journal of Experimental Biology, December 1
Early to bed and early to rise keeps depression away. Or at least switching the lights off when it is time to sleep at night, helps. Mice which were subjected to 24 hours of light were more prone to depression than mice which had the choice to escape into a dark, opaque tube whenever they wanted. This research extends to the impact of unnatural light cycles on human health. Working night shifts, watching television till late or partying at late hours disrupts the body’s circadian clock. This was known. The new research says it also leads to depression, gradually.
Behavioural Brain Research, December 28
Methane has a short lifespan on Mars but its reserves are constantly renewed. This makes researchers wonder if microbes have a hand in it. This is how they explain the red planet might have life: Initially it was believed that meteorites crashing into Mars’ atmosphere supplied the methane. But when researchers simulated conditions leading to the crashes, they found that the rocks released the gas at levels much lower than the available atmospheric levels. These are then depleted in sunlight and constantly replenished by a source that could very well be microbes like methane-producing bacteria. This is what scientists from nasa in the US and esa (European Space Agency) will figure out on their joint mission to Mars in 2018.
Earth and Planetary Science Letters, December 9
Corn would soon lend a hand in preserving tinned fish. A starch-like compound called phytoglycogen forms 30 per cent of the dry mass of sweet corn. This compound was modified to act as an emulsifier. These are chemicals added to tinned foods that prevent oil droplets in the food from oxidizing that changes the chemical structure of the oil; the food goes rancid. The phytoglycogen nanoparticle is thicker and denser than most other emulsifiers and creates a better oxygen barrier, thus prolonging the shelf life of preserved foods.
Journal of Agricultural and Food Chemistry, December
Indians are ancient
The question on whether there were two waves of migration into Asia (from the south and the north) has been answered. For the first time genetic ancestry of Asian populations was plotted on a map that confirms there was only one wave of migration which started from Southeast Asia.
Science, December 10