Monthly Archives: Dezembro 2015

Bacterias de la antártida ayudarían a tratar el cáncer

Bajo las condiciones extremas de los glaciares de la Antártida habitan unas bacterias capaces de sintetizar en su interior nanopartículas fluorescentes que podrían ser utilizadas para marcar células tumorales y rastrear la metástasis de diferentes tipos de cáncer.

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Investigadores chilenos encontraram bactérias na Antárctida capazes de produzir pigmentos para identificar células cancerosas.

See on Scoop.itBioinformática

Rocky Wolf 1061c Planet Sitting in the Habitable Zone of a Nearby Star

A team of researchers from the University of New South Wales (UNSW) have discovered a rocky planet that sits perfectly in the habitable “Goldilocks” zone of a Sun-like star located just 14 light years away from Earth.


Just last month, astronomers from the Edinburgh University had found a planet-like object without any parent star about 75 light years away from Earth The new planet discovered, named Wolf 1061c, is about four times the size of Earth and is the nearest potentially habitable world, according to scientists. It has a rocky, solid surface which is usually considered to be necessary to support alien life. Presence of a planet in the “Goldilocks zone” makes the planet neither too hot nor too cold, meaning the planet could support life. Wolf 1061 lies in Ophiucus constellation and is the 35th closest star to Earth.


Lead researcher Dr Duncan Wright revealed in a statement that their team has actually found three planets revolving around a red dwarf star. These planets are of “low enough mass” and have a solid surface. Of these three planets, one is located very close to the star, while the other one lies too far out. The middle of these three planets, Wolf 1061c, “sits within the ‘Goldilocks’ zone where it might be possible for liquid water – and maybe even life – to exist.”

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Foi descoberto um potencial candidato de planeta habitável que orbita uma estrela anã vermelha "apenas" a 13 anos-luz da Terra.
Estima-se que o planeta se encontre na hipotética zona de habitabilidade da estrela.

See on Scoop.itAnother Earths in the Universe

Asteroid impact helped create the birds we know today

By Sid Perkins 11 December 2015 2:00 pm

Every bird alive today can trace its ancestry to creatures that lived about 95 million years ago on a chunk of land that split off from the supercontinent Gondwana, a new study suggests. The new family tree, compiled using information from fossils and from genetic analyses of modern birds, also reveals that this lineage underwent a major burst of evolution after an asteroid slammed into Earth about 66 million years ago and killed off the rest of their dinosaurian kin.

“This is one of the most comprehensive studies that attempts to date when these evolutionary divergences happened,” says Luis Chiappe, a vertebrate paleontologist at the Natural History Museum of Los Angeles County in California, who wasn’t involved in the new research.

Modern birds, a group called Neornithes (a name that combines neo and a variant of ornis, the Greek words for “new” and “bird,” respectively) are the most diverse and widespread vertebrates on Earth today. Previous studies that used only information from genetic analyses of current species have suggested that birds arose anywhere from 72 million to 170 million years ago. But the new study, which includes anatomical data extinct species preserved in the fossil record, narrows that window considerably, says Joel Cracraft, an ornithologist at the American Museum of Natural History in New York City.

He and museum colleague Santiago Claramunt, also an ornithologist, didn’t include well-known ancient birds such as Archaeopteryx and Confuciusornis, which belonged to lineages that eventually died out. They only looked at species that belonged to the three major groups of birds alive today: Palaeognathae (ostriches and their close relatives), Galloanseres (waterfowl, pheasants, and their close kin), and Neoaves (all other birds).

The team’s genetic information came from analyses of two particular genes from 230 species representing all major subgroups of modern birds. (Mutations in those genes, which are related to basic biochemical processes that take place in all cells, helped the researchers estimate when those groups arose or diverged from their closest relatives, Cracraft says.) Anatomical data from 130 extinct species that had once lived worldwide helped the team figure out when and where those groups originated, as well as how quickly they evolved.

The results suggest that the last common ancestor of all modern birds—in other words, the species at the base of the evolutionary family tree that includes all living bird species—lived in West Gondwana, a landmass that included what are now fragments of South America and large portions of Antarctica, about 95 million years ago. What’s more, all three major groups—Palaeognathae, Galloanseres, and Neoaves—had already arisen by the time the dino-killing asteroid smacked our planet 66 million years ago, the researchers report online today in Science Advances. So although the resulting die-offs may not have triggered the original diversification of birds, by eliminating many ecological competitors, the extinction provided opportunities for survivors to diversify and spread, Cracraft says.

The team’s results are “reasonably convincing, and their new insights make sense,” says Edward Braun, an evolutionary biologist at the University of Florida in Gainesville.

Among those new insights is a notion of how birds spread throughout the ancient world. Whereas some groups spread southward through the fragments of Gondwana to reach what are now Australia and New Zealand, others spread north to what is now North America. From there, some species spread eastward into Eurasia and Africa and others moved westward, across occasional land bridges exposed when global sea levels were low, to eastern Asia. In particular, the new data “better match the origins of certain groups of birds once thought to have arisen in Africa,” Braun says.

Although the new study answers many questions, it poses many more, Chiappe says. Among them: Why did a large class of now-extinct birds called Enantiornithines (which were superficially similar to modern birds) die out? That’s especially mysterious because Enantiornithines were exceptionally abundant (they apparently outnumbered the ancestors of modern birds before the asteroid struck) and had presumably played the same ecological roles as the ancestors of modern birds, which survived the mass extinctions.

Posted in Plants & Animals

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As aves, enquanto descendentes directos dos dinossauros conheceram uma grande explosão de diversidade precisamente no final do domínio dos seus originadores, na fronteira K/T, a partir da América do Sul, é o que dizem investigadores a partir de evidências geográficas do passado.


See on Scoop.itMilhares de milhões de anos… a mesma Terra !

SRA Toolkit: the SRA database at your fingertips

The Sequence Read Archive (SRA), NCBI’s largest growing repository of molecular data, archives raw sequencing data and alignment information from high-throughput sequencing platforms, including Roche 454 GS Systems®, Illumina’s Genome Analyzer®, and Complete Genomics® systems.

Researchers commonly use SRA data to make discoveries via comparison of data sets. Data sets can be compared through the SRA web interface, but if you want to integrate these downloads and file conversions into an already existing pipeline, or you simply prefer using a command-line interface, we recommend using the SRA Toolkit.

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O SRA é um formato usado para partilhar data sets. Permite a compressão do dataset de forma a poder ser facilmente partilhado rapidamente.

See on Scoop.itBioinformática

Microbial Changes of Decomposition

The changes that occur to the microbiome upon death may someday be harnessed as a forensic tool.

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A análise metagenómica de um cadáver pode ser usada para ter uma ideia do tempo de morte em função da variação das comunidades microbianas ao longo do tempo.

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Humans may harbor more than 100 genes from other organisms

You’re not completely human, at least when it comes to the genetic material inside your cells. You—and everyone else—may harbor as many as 145 genes that have jumped from bacteria, other single-celled organisms, and viruses and made themselves at home in the human genome. That’s the conclusion of a new study, which provides some of the broadest evidence yet that, throughout evolutionary history, genes from other branches of life have become part of animal cells.

“This means that the tree of life isn’t the stereotypical tree with perfectly branching lineages,” says biologist Alastair Crisp of the University of Cambridge in the United Kingdom, an author of the new paper. “In reality, it’s more like one of those Amazonian strangler figs where the roots are all tangled and crossing back across each other.”

Scientists knew that horizontal gene transfer—the movement of genetic information between organisms other than parent-to-offspring inheritance—is commonplace in bacteria and simple eukaryotes. The process lets the organisms quickly share an antibiotic-resistance set of genes to adapt to an antibiotic, for instance. But whether genes have been horizontally transferred into higher organisms—like primates—has been disputed. Like in bacteria, it’s been proposed that animal cells could integrate foreign genetic material that’s introduced as small fragments of DNA or carried into cells by viruses. But proving that a bit of DNA in the human genome originally came from another organism is tricky.

Crisp and his colleagues analyzed the genome sequences of 40 different animal species, ranging from fruit flies and roundworms to zebrafish, gorillas, and humans. For each gene in the genomes, the scientists searched existing databases to find close matches—both among other animals and among nonanimals, including plants, fungi, bacteria, and viruses. When an animal’s gene more closely matched a gene from a nonanimal than any other animals, the researchers took a closer look, using computational methods to determine whether the initial database search had missed something.

In all, the researchers pinpointed hundreds of genes that appeared to have been transferred from bacteria, archaea, fungi, other microorganisms, and plants to animals, they report online today in Genome Biology. In the case of humans, they found 145 genes that seemed to have jumped from simpler organisms, including 17 that had been reported in the past as possible horizontal gene transfers.

“I think what this shows it that horizontal gene transfer is not just confined to microorganisms but has played a role in the evolution of many animals,” Crisp says, “perhaps even all animals.

The paper doesn’t give any hints as to how the genes—which now play established roles in metabolism, immune responses, and basic biochemistry—may have been transferred or the exact timeline of the jumps, he says. That will take more work.

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Cientistas encontraram no nosso próprio genoma  genes que aparentam provir de origens completamente díspares: desde vírus ou fungos.


See on Scoop.itBioinformática