Amazing Science

Dozens of butterfly species are endangered or threatened. A handful are shown in this photo gallery, but most don’t even have a picture on the internet. If they disappear, their beauty could be remembered as nothing more than a disembodied name.

Recent research has shown that the transcription and translation of genes, or even the presence of DNA in the cell, are not necessary for the daily ("circadian") rhythms to occur. This article gives a nice summary about the history of circadian rhythms discoveries.

For decades, scientists have known that DNA consists of four basic units -- adenine, guanine, thymine and cytosine. Those four bases have been taught in science textbooks and have formed the basis of the growing knowledge regarding how genes code for life. Yet in recent history, scientists have expanded that list from four to six.

Now, researchers from the UNC School of Medicine have discovered the seventh and eighth bases of DNA. These last two bases -- called 5-formylcytosine and 5 carboxylcytosine -- are actually versions of cytosine that have been modified by Tet proteins, molecular entities thought to play a role in DNA demethylation and stem cell reprogramming.

Life must have begun with a simple molecule that could reproduce itself – and now we think we know how to make one.

Natural selection has been wiping out species with subpar adaptive strategies. Among the casualties: dinosaurs, mammoths, Neanderthals, and all manner of megafauna that we’d all love to see first-hand. Alas, mother nature hasn’t been particularly forgiving of species selected against: for four billion years, extinction meant extinction. That is until 2009 when scientists used frozen tissue to successfully clone the Pyrenean ibex, a kind of goat native to the Pyrenees Mountains between Spain and France, making it the first species to become un-extinct.

Video collection about cloning: http://tinyurl.com/76dgxqm

Viruses are by far the most abundant 'lifeforms' in the oceans and are the reservoir of most of the genetic diversity in the sea. The estimated 10^30 viruses in the ocean, if stretched end to end, would span farther than the nearest 60 galaxies. Every second, approximately 10^23 viral infections occur in the ocean. These infections are a major source of mortality, and cause disease in a range of organisms, from shrimp to whales.

As a result, viruses influence the composition of marine communities and are a major force behind biogeochemical cycles. Each infection has the potential to introduce new genetic information into an organism or progeny virus, thereby driving the evolution of both host and viral assemblages. Probing this vast reservoir of genetic and biological diversity continues to yield exciting discoveries.

Viruses can be found in every environment on the Earth, but their importance is perhaps most evident in the oceans, where they are known to be the reservoir of most of the genetic diversity. Viruses kill approximately 20% of the oceanic microbial biomass daily, which has a significant impact on nutrient and energy cycles. This Review highlights areas in which marine virology is advancing quickly or seems to be poised for paradigm-shifting discoveries.

Developing the necessary techniques to obtain accurate and reproducible estimates of the distribution and abundance of marine viruses has been a challenge for researchers. Sub-populations of both viruses and host cells can now be discriminated using flow cytometry. Viral abundance generally co-varies with prokaryotic abundance and productivity, but marked differences in this relationship have been reported in different marine environments.

Quantifying the effects of viruses on marine prokaryotic and eukaryotic heterotrophic and autotrophic communities is also a challenging area, and remains one of the biggest obstacles to incorporating viral-mediated processes into global models of nutrient and energy cycling.

Our knowledge of the diversity of viruses in marine environments has increased greatly with the development of metagenomic approaches. The interactions between viruses and the organisms they infect ultimately control the genetic diversity of viruses and potentially influence the composition of microbial communities. However, the experimental evidence that supports the hypothesis that viruses regulate microbial diversity in nature is ambiguous. This is perhaps not surprising as the effects of viruses on their host cells depend on transient associations, which might lead us to expect that the influences of viruses on host populations will also be spatially and temporally variable.

Viruses/bacteria video collection: http://tinyurl.com/7plkwe3 

The hagfish looks like an easy meal. Its sinuous, eel-like body has no obvious defences, but any predator that moves in for a bite is in for a nasty surprise. The hagfish releases a quick-setting slime that clogs up the predator’s gills, causing it to gag, choke and flee. Scientists have known about this repulsive defence for decades, but Vincent Zintzen has finally filmed it in the wild. His videos also prove that hagfish, generally thought to be scavengers of the abyss, are also active hunters that can drag tiny fish from their burrows.

Hagfish are sometimes classed as fish although that’s in dispute, for they lack both backbones and jaws. Instead, their mouths contain a wide plate of cartilage, armed with two rows of horny teeth. It uses these to rasp away at carcasses that sink from above. Watch a dying whale settle on the ocean floor, and it will soon be covered in writhing hagfishes.

They are disgusting feeders. They burrow deep into corpses and eat their way out, and can even absorb nutrients through their skin. And if they’re threatened or provoked, they produce slime – lots of slime, oozing from the hundreds of pores that line their bodies. The slime consists of large mucus proteins called mucins, linked together by longer protein threads. When it mixes with seawater, it massively expands, becoming almost a thousand times more dilute than other animal mucus.

When a bacterial cell divides into two daughter cells and those two cells divide into four more daughters, then 8, then 16 and so on, the result, biologists have long assumed, is an eternally youthful population of bacteria. However, new research concludes that not only do bacteria age, but that their ability to age allows them to improve the evolutionary fitness of their population by diversifying their reproductive investment between older and more youthful daughters.

Caenorhabditis elegans, as the roundworm is properly known, is a tiny, transparent animal just a millimeter long. In nature, it feeds on the bacteria that thrive in rotting plants and animals. It is a favorite laboratory organism for several reasons, including the comparative simplicity of its brain, which has just 302 neurons and 8,000 synapses, or neuron-to-neuron connections. These connections are pretty much the same from one individual to another, meaning that in all worms the brain is wired up in essentially the same way. Such a system is considerably easier to understand than the human brain, a structure with billions of neurons, 100,000 miles of biological wiring and 100 trillion synapses.

Why does the universe exist? For that matter, why do people? Can you even be sure that you do? 13.7 billion years ago, the universe was born in a cosmic fireball. Roughly 10 billion years later, the planet we call Earth gave birth to life, which eventually led to you. The probability of that sequence of events is absolutely minuscule, and yet it still happened.

Take a step back from the unlikeliness of your own personal existence and things get even more mind-boggling. Why does the universe exist at all? Why is it fine-tuned to human life? Why does it seem to be telling us that there are other universes out there, even other yours? 

The Russian sample-return spacecraft will carry a zoo of microbes to Phobos and back to test whether life can survive the interplanetary journey.