Science

Mitochondria are the cell’s workhorse, transforming the calories we eat into useable energy. They have also been the subject of lots of scrutiny over longevity, since lifespan is intimately tied up with metabolism. Now a new study reports that mitochondrial malfunction may actually be the key to extending life.Although loss of mitochondrial function has been associated with increased lifespan in a number of species, the reasons behind this effect have been poorly understood. It’s also been known that low levels of stress within a cell—for instance, running on low energy—can increase an animal’s lifespan. Most of these studies have however been done in flies, worms and yeast. Thus a Swiss research team led by Riekelt Houtkooper decided to examine stress and longevity in mice, as well as the worm C. elegans.In mice, they analyzed a set of related mouse strains that have lots of natural variation in lifespan—they live anywhere from 1 to 2 1/2 years. With genetic tests the researchers were able to pin down three specific genes that seemed to be the key determinants of the mouse’s lifespan. Mice with lower activity in these genes lived up to 2.5 times longer than those with high activity.Then, in worms, the researchers artificially damped down the activity of the equivalent genes and observed how long they lived. One gene stuck out as most important: Worms with a dampened mrps-5 gene lived 60 percent longer than normal.The key, the researchers say, appears to be that loss of mrps-5 causes the mitochondria to send a kind of cellular SOS to the nucleus. The nucleus’s response, called the “mitochondrial unfolded protein response,” is to send out protective proteins. This is interesting. It also runs contrary to the family history. We have very long lived folks in the family, but its in the patrilineal side of things. The men live fairly long, often inspite of their lifestyles rather than because of them. That would seem to preclude the source of longevity being a mitochondria based source. Rather it would argue to be a y linked trait. Interesting if we might be carrying something else. What happens if you combine them (assuming we haven't just been lucky).

THE INFLUENCE OF THERMAL EVOLUTION IN THE MAGNETIC PROTECTION OF TERRESTRIAL PLANETS Authors:1. Jorge I. Zuluaga (a) 2. Sebastian Bustamante (a) 3. Pablo A. Cuartas (a) 4. Jaime H. Hoyos (b)Affiliations:a. Instituto de Física-FCEN, Universidad de Antioquia, Calle 67 No. 53-108, Medellín, Colombiab. Departamento de Ciencias Básicas, Universidad de Medellín, Carrera 87 No. 30-65, Medellín, Colombia Abstract:Magnetic protection of potentially habitable planets plays a central role in determining their actual habitability and/or the chances of detecting atmospheric biosignatures. Here we develop a thermal evolution model of potentially habitable Earth-like planets and super-Earths (SEs). Using up-to-date dynamo-scaling laws, we predict the properties of core dynamo magnetic fields and study the influence of thermal evolution on their properties. The level of magnetic protection of tidally locked and unlocked planets is estimated by combining simplified models of the planetary magnetosphere and a phenomenological description of the stellar wind. Thermal evolution introduces a strong dependence of magnetic protection on planetary mass and rotation rate. Tidally locked terrestrial planets with an Earth-like composition would have early dayside magnetopause distances between 1.5 and 4.0 Rp , larger than previously estimated. Unlocked planets with periods of rotation ~1 day are protected by magnetospheres extending between 3 and 8 Rp . Our results are robust in comparison with variations in planetary bulk composition and uncertainties in other critical model parameters. For illustration purposes, the thermal evolution and magnetic protection of the potentially habitable SEs GL 581d, GJ 667Cc, and HD 40307g were also studied. Assuming an Earth-like composition, we found that the dynamos of these planets are already extinct or close to being shut down. While GL 581d is the best protected, the protection of HD 40307g cannot be reliably estimated. GJ 667Cc, even under optimistic conditions, seems to be severely exposed to the stellar wind, and, under the conditions of our model, has probably suffered massive atmospheric losses.

Dinosaurs are often thought of as large, fierce animals, but new research highlights a previously overlooked diversity of small dinosaurs. Paleontologists have now described a new dinosaur, the smallest plant-eating dinosaur species known from Canada.

Malaria-carrying mosquitoes appear to be manipulated by the parasites they carry, but this manipulation may simply be part of the mosquitoes' immune response, according to entomologists.

Children living in households where the parents are married are less likely to be obese, according to new research.

Researchers have created a new type of transparent electrode that might find uses in solar cells, flexible displays for computers and consumer electronics and future "optoelectronic" circuits for sensors and information processing.

Relatives of the Norway spruce are some of the oldest living things on the planet. They haven't used all that time to tidy up their genomes, though. National Park Service Last week we heard about the genome of a plant that pushed the limits of compacting its DNA: the bladderwort seems to have done away with of most of the genetic material that typically makes plant and animal genomes so large without any apparent ill effects. This week, the genome of a different plant is in the spotlight: the Norway spruce (Picea abies), which also seems to suffer no ill effects, even though it has picked up an enormous amount of DNA. Each one of its chromosomes is nearly the size of the entire human genome—and it has a dozen of them. When researchers looked at what all that extra DNA might be doing, they came up with a simple answer: probably not anything useful. If you're aware of the Norway spruce, it's probably because you have been shopping for a Christmas tree. But conifers (technically Gymnosperms, although the group includes gingkoes and a few other species) are some of the most phenomenally successful organisms on Earth. They've dominated forests for over 200 million years, and members of the group include the tallest, heaviest, and oldest things currently alive. All of them seem to have managed this despite having a staggeringly inefficient genome management style. Unlike many groups that vary widely in the number of chromosomes their species carry, pretty much all the Gymnosperms have a dozen pairs of chromosomes. And pretty much all of these chromosomes are up in the area of two billion bases long, or a bit smaller than the human genome. That size is so consistent, in fact, that the authors think the trees might be pushing up against the limits of how much stuff you can put in a chromosome and still get it copied and shared between two cells when they divide. In other words, if firs wanted to carry any more DNA than they already do, they'd have to start making new chromosomes. Read 6 remaining paragraphs | Comments

In a series of lab experiments designed to unravel the workings of a key enzyme widely considered a possible trigger of rheumatoid arthritis, researchers have found that in the most severe cases of the disease, the immune system makes a unique subset of antibodies that have a disease-promoting role.

FuzzNugget writes "A contributor at ScienceBlogs.com has compiled and published a shockingly long list of systematic attacks on scientific research committed by the Canadian government since the conservatives came to power in 2006. This anti-scientific scourge includes muzzling scientists, shutting down research centers, industry deregulation and re-purposing the National Research Council to align with business interests instead of doing real science. It will be another two years before Canadians have the chance to go to the polls, but how much more damage will be done in the meantime?" Read more of this story at Slashdot.

The elliptical galaxy NGC 4150. Observation of a merger between two galaxies early in the life of the Universe could explain the origin of large elliptical galaxies. NASA, ESA, R.M. Crockett (University of Oxford, U.K.), S. Kaviraj (Imperial College London and University of Oxford, U.K.), J. Silk (University of Oxford), M. Mutchler (Space Telescope Science Institute, Baltimore), R. O'Connell (University of Virginia, Charlottesville), and the WFC3 Scientific Oversight Committee The largest galaxies in the Universe aren't beautiful spirals like our Milky Way; they are enormous egg-shaped structures known as giant elliptical galaxies. We don't know how they formed, but observations of very distant and bright galaxies revealed information about the formation of smaller elliptical galaxies. The giants remained mysterious. Where one galaxy is insufficient, two may do instead. A new set of observations caught two bright elliptical galaxies right before the act of merging into one that would have a combined mass large enough to make the equivalent of 400 billion Suns. Hai Fu and colleagues determined that these galaxies collided more than 10 billion years ago and that the merger was driving extremely rapid star formation, at least ten times the rate seen in ordinary galaxies. Based on these observations, the researchers concluded that such collisions could be responsible for the birth of the largest galaxies, allowing for most of them to finish forming by 9.5 billion years ago. Nearby elliptical galaxies contain virtually no young stars and are poor in the raw ingredients of star formation—gas and dust. However, based on observation, those stars must have formed fairly rapidly as a group about 10 billion years ago. Such aggressive star formation would pump a lot of light out, leading to extremely bright galaxies. Read 6 remaining paragraphs | Comments