KREUZADER (Posts tagged biology)

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“Scientists have recently made a wondrous variety of mini-brains — 3-D cultures of neural cells that model basic properties of living brains — but a new finding could add to the field’s growing excitement in an entirely new “vein”: Brown University’s...

Scientists have recently made a wondrous variety of mini-brains — 3-D cultures of neural cells that model basic properties of living brains — but a new finding could add to the field’s growing excitement in an entirely new “vein”: Brown University’s mini-brains now grow blood vessels, too.

The networks of capillaries within the little balls of nervous system cells could enable new kinds of large-scale lab investigations into diseases, such as stroke or concussion, where the interaction between the brain and its circulatory system is paramount, said Diane Hoffman-Kim, senior author of the study in The Journal of Neuroscience Methods. More fundamentally, vasculature makes mini-brains more realistic models of natural noggins.

“This is exciting because real brains have vasculature,” said Hoffman-Kim, an associate professor of medical science and of engineering at Brown. “We rely on it. For our neurons to do their thing, they have to be close to some blood vessels. If we are going to study lab models of the brain, we would love for them to have vasculature, too.”

Source: news.brown.edu
biology neuroscience brain
Organisms created with synthetic DNA pave way for entirely new life forms “In a report published on Monday, the scientists describe the modified microbes as a starting point for efforts to “create organisms with wholly unnatural attributes and traits...

Organisms created with synthetic DNA pave way for entirely new life forms 

In a report published on Monday, the scientists describe the modified microbes as a starting point for efforts to “create organisms with wholly unnatural attributes and traits not found elsewhere in nature.” The cells constitute a “stable form of semi-synthetic life” and “lay the foundation for achieving the central goal of synthetic biology: the creation of new life forms and functions,” they add.

Floyd Romesberg and his team at the Scripps Research Institute in California expanded the genetic code from four letters to six by adding two new molecules they call X and Y and adding them to the bugs’ genetic makeup. The microbes are modified to absorb the new genetic material which the scientists make separately and then feed to the cells.

The need to supply the bugs with the X and Y molecules is meant to ensure that the cells will die should they somehow get out of the lab. But Romesberg said that despite the protective measure, he still gets asked if he has seen Jurassic Park. In the 1993 movie, Jeff Goldblum questions whether the park’s dinosaurs might breed in the wild despite the failsafes built into their genetic makeup. “What the movie depicted is very different to our failsafe,” Romesberg said. “Our failsafe is based on the availability of X and Y and the cell could never make them.”

“In addition, evolution works by starting with something close and then changing what it can do in small steps. Our X and Y are unlike natural DNA, so nature has nothing close to start with. We have shown many times that when you do not provide X and Y, the cells die, every time,” he added.

more here

Source: theguardian.com
biology genetic engineering
Scientists create a part-human, part-pig embryo“The experiment, described Thursday in the journal Cell, involves injecting human stem cells into the embryo of a pig, then implanting the embryo in the uterus of a sow and allowing it to grow. After...

Scientists create a part-human, part-pig embryo

The experiment, described Thursday in the journal Cell, involves injecting human stem cells into the embryo of a pig, then implanting the embryo in the uterus of a sow and allowing it to grow. After four weeks, the stem cells had developed into the precursors of various tissue types, including heart, liver and neurons, and a small fraction of the developing pig was made up of human cells.

The human-pig hybrid — dubbed a “chimera” for the mythical creature with a lion’s head, a goat’s body and a serpent’s tail — was “highly inefficient,” the researchers cautioned. But it’s the most successful human-animal chimera and a significant step toward the development of animal embryos with functioning human organs.

In a study published a day earlier, an international team of researchers demonstrated that organs for transplant can be grown in chimera embryos that are part-mouse, part-rat. Writing in Nature, the researchers reported Wednesday that they were able to grow a mouse pancreas inside a rat embryo, then transfer insulin-secreting tissue from that organ into diabetic mice, alleviating their illness without triggering an immune response.

It was the first demonstration that such an interspecies organ transplant is possible. Researchers hope that one day doctors may be able to grow human tissue using chimera embryos in farm animals, making organs available for sick humans who might otherwise wait years for a transplant.

Source: Washington Post
biology genetic engineering
Bacteria Send Electrical Pulses as Recruitment Ads“Bacteria are simple, supposedly. Each one consists of a single microscopic cell. But together, these cells have a surprisingly rich social life, and are capable of unexpectedly complex behaviors. For...

Bacteria Send Electrical Pulses as Recruitment Ads

Bacteria are simple, supposedly. Each one consists of a single microscopic cell. But together, these cells have a surprisingly rich social life, and are capable of unexpectedly complex behaviors. For example, a team of scientists led by Gürol Süel from the University of California, San Diego, now has shown that groups of bacteria can coordinate their actions and bolster their ranks by sending long-range electrical signals, not unlike those that course along our neurons and power our thoughts.

Source: The Atlantic
bacteria biology
“During photosynthesis, plants harvest light and, though a chemical process involving water and carbon dioxide, convert this into fuel for life. A vital part of this process is using the light energy to split water into oxygen and hydrogen.This is...
During photosynthesis, plants harvest light and, though a chemical process involving water and carbon dioxide, convert this into fuel for life. A vital part of this process is using the light energy to split water into oxygen and hydrogen.

This is done by an enzyme called Photosystem II. Light energy is harvested by ‘antennae’, and transferred to the reaction centre of Photosystem II, which strips electrons from water. This conversion of excitation energy into chemical energy, known as ‘charge separation’, is the first step in splitting water.

It was previously thought that the process of charge separation in the reaction centre was a ‘bottleneck’ in photosynthesis - the slowest step in the process - rather than the transfer of energy along the antennae.

Since the structure of Photosystem II was first determined 2001, there was some suggestion that in fact it could be the energy transfer step that was slowest, but it was not yet possible to prove experimentally.

Now, using ultrafast imaging of electronic excitations that uses small crystals of Photosystem II, scientists from Imperial College London and Johannes Kepler University (JKU) in Austria have shown that the slowest step is in fact the process through which the plants harvest light and transfer its energy through the antennae to the reaction centre.

Source: www3.imperial.ac.uk
biology biochemistry
Everyday bat vocalizations contain information about emitter, addressee, context, and behavior“Animal vocal communication is often diverse and structured. Yet, the information concealed in animal vocalizations remains elusive. Several studies have...

Everyday bat vocalizations contain information about emitter, addressee, context, and behavior

Animal vocal communication is often diverse and structured. Yet, the information concealed in animal vocalizations remains elusive. Several studies have shown that animal calls convey information about their emitter and the context. Often, these studies focus on specific types of calls, as it is rarely possible to probe an entire vocal repertoire at once. In this study, we continuously monitored Egyptian fruit bats for months, recording audio and video around-the-clock. We analyzed almost 15,000 vocalizations, which accompanied the everyday interactions of the bats, and were all directed toward specific individuals, rather than broadcast. We found that bat vocalizations carry ample information about the identity of the emitter, the context of the call, the behavioral response to the call, and even the call’s addressee. Our results underline the importance of studying the mundane, pairwise, directed, vocal interactions of animals.

Source: nature.com
biology bats
“ In molecular engineering, two cuts could be better than one. Today scientists report in the Proceedings of the National Academy of Sciences on a new tool that could take the CRISPR gene-editing technique to the next level. The tool, called a...

In molecular engineering, two cuts could be better than one. Today scientists report in the Proceedings of the National Academy of Sciences on a new tool that could take the CRISPR gene-editing technique to the next level. The tool, called a “molecular LEGO,” could improve CRISPR’s ability to cut away damaged DNA and help treat diseases like cystic fibrosis and leukemia.

At it’s most basic level, CRISPR (clustered regularly interspaced short palindromic repeats) is a way of cutting DNA at a specific spot using an enzyme called Cas9. Once the cut is made, the DNA automatically starts to repair it, causing the enzyme to cut the DNA again, initiating repair. It’s a futile cycle.

[…]

The researchers, including Jason Wolfs, the lead author of the paper, found a way to snap the Cas9 enzyme to an enzyme with the complicated name I-TevI nuclease domain. The resulting TevCas9 combo can be thought of as a molecular Lego with chemical blades on each end.

When used on DNA, the TevCas9 attaches to a larger segment of genetic code than Cas9 alone and instead of making a small, precise cut, TevCas9 cuts out a larger section. Removing a larger block of DNA will not only reduce the inefficient cycle of cutting and repairing, but could also prevent Cas9 from snipping unintended parts of the genome.

Source: seeker.com
crispr molecular biology biology genetic engineering
A Feathered Dinosaur Tail with Primitive Plumage Trapped in Mid-Cretaceous Amber“Here we describe the feathered tail of a non-avialan theropod preserved in mid-Cretaceous (∼99 Ma) amber from Kachin State, Myanmar [17], with plumage structure that...

A Feathered Dinosaur Tail with Primitive Plumage Trapped in Mid-Cretaceous Amber

Here we describe the feathered tail of a non-avialan theropod preserved in mid-Cretaceous (∼99 Ma) amber from Kachin State, Myanmar [17], with plumage structure that directly informs the evolutionary developmental pathway of feathers. This specimen provides an opportunity to document pristine feathers in direct association with a putative juvenile coelurosaur, preserving fine morphological details, including the spatial arrangement of follicles and feathers on the body, and micrometer-scale features of the plumage. Many feathers exhibit a short, slender rachis with alternating barbs and a uniform series of contiguous barbules, supporting the developmental hypothesis that barbs already possessed barbules when they fused to form the rachis [19]. Beneath the feathers, carbonized soft tissues offer a glimpse of preservational potential and history for the inclusion; abundant Fe2+ suggests that vestiges of primary hemoglobin and ferritin remain trapped within the tail. The new finding highlights the unique preservation potential of amber for understanding the morphology and evolution of coelurosaurian integumentary structures.

Source: cell.com
biology dinosaur
“Scientists have indexed thousands of bioluminescent organisms across the tree of life, and they expect to add many more. Yet researchers have long wondered how bioluminescence came to be. Now, as explained in several recently released studies,...

Scientists have indexed thousands of bioluminescent organisms across the tree of life, and they expect to add many more. Yet researchers have long wondered how bioluminescence came to be. Now, as explained in several recently released studies, researchers have made significant progress in understanding the origins of bioluminescence — both evolutionary and chemical. The new understanding may one day allow bioluminescence to be used as a tool in biology and medical research.

[…]

In nearly all shining organisms, bioluminescence requires three ingredients: oxygen, a light-emitting pigment called a luciferin (from the Latin word lucifer, meaning light-bringing), and an enzyme called a luciferase. When a luciferin reacts with oxygen — a process facilitated by luciferase — it forms an excited, unstable compound that emits light when it returns to its lowest energy state.

Curiously, there are far fewer luciferins than luciferases. While species tend to have unique luciferases, many share the same luciferin. Just four luciferins are responsible for most of the light production in the ocean. Of close to 20 groups of bioluminescent organisms in the world, a luciferin called coelenterazine is the light-emitter in nine.

Yet it would be a mistake to assume that all coelenterazine-containing organisms had evolved from a single luminous ancestor. If they had, asked Warren Francis, a biologist at Ludwig Maximilian University in Munich, then why did they develop such a wide variety of luciferases? Presumably the first luciferin-luciferase pair would have survived and multiplied.

It’s more likely that many of these species don’t make coelenterazine themselves. Instead, they get it from their diet, said Yuichi Oba, a professor of biology at Chubu University in Japan.

Source: quantamagazine.org
biology
Ducklings ‘maintain two separate memory banks of visual information’“In this new study, published in the journal Animal Behaviour, ducklings were initially presented with either a red or a blue duck decoy, which moved in a circular path, while...

Ducklings ‘maintain two separate memory banks of visual information’

In this new study, published in the journal Animal Behaviour, ducklings were initially presented with either a red or a blue duck decoy, which moved in a circular path, while wearing an eyepatch over one eye.

The ducklings 'imprinted’ on this maternal surrogate, learning with this first eye to follow the coloured decoy they had been presented with. In subsequent choice tests over the next three hours, each duckling was presented with both the red and blue decoys simultaneously while wearing either no eyepatch, a patch over the same eye as in training, or a patch over the other eye – the one that had seen the decoy during training.

The ducklings that made their choice with both eyes, or with the same eye with which they had been trained, accurately preferred to follow the original decoy. But the ducklings wearing a patch over the original eye, so that only the naive eye was available during testing, showed no reliable preference between the two decoys.

[…]

Professor Alex Kacelnik of Oxford University’s Department of Zoology said: 'This result illustrates the diversity of the kinds of minds possessed by different organisms. The mental experience of a bird is likely to be profoundly different from our own, and we are still far from having a clear picture of it. As mammals, the idea that when using one eye we may not be able to identify things first seen by the other eye seems very strange, but this is probably what happens to birds and most other vertebrates including reptiles, amphibians and fish. Since only eutherian mammals – that is, excluding marsupials such as kangaroos, and monotremes like the platypus – have a corpus callosum, it is possible that the unified visual mind may be a mammalian innovation.’

Source: ox.ac.uk
ducks birds biology neuroscience
CRISPR gene-editing tested in a person for the first time“A Chinese group has become the first to inject a person with cells that contain genes edited using the revolutionary CRISPR–Cas9 technique. On 28 October, a team led by oncologist Lu You at...

CRISPR gene-editing tested in a person for the first time

A Chinese group has become the first to inject a person with cells that contain genes edited using the revolutionary CRISPR–Cas9 technique.

On 28 October, a team led by oncologist Lu You at Sichuan University in Chengdu delivered the modified cells into a patient with aggressive lung cancer as part of a clinical trial at the West China Hospital, also in Chengdu.

Earlier clinical trials using cells edited with a different technique have excited clinicians. The introduction of CRISPR, which is simpler and more efficient than other techniques, will probably accelerate the race to get gene-edited cells into the clinic across the world, says Carl June, who specializes in immunotherapy at the University of Pennsylvania in Philadelphia and led one of the earlier studies.

Source: nature.com
medicine crispr-cas9 crispr biology genetic engineering
‘Minibrains’ Could Help Drug Discovery For Zika And For Alzheimer’s “Some tiny clusters of brain cells grown in a lab dish are making big news at this week’s Society for Neuroscience meeting in San Diego. Known as “minibrains,” these rudimentary...

‘Minibrains’ Could Help Drug Discovery For Zika And For Alzheimer’s

Some tiny clusters of brain cells grown in a lab dish are making big news at this week’s Society for Neuroscience meeting in San Diego.

Known as “minibrains,” these rudimentary networks of cells are small enough to fit on the head of a pin, but already are providing researchers with insights into everything from early brain development to Down syndrome, Alzheimer’s and Zika.

At a Sunday press conference at the neuroscience meeting, researchers said minibrains are helping them figure out how the Zika virus can disrupt human brain formation in the early stages of fetal development.

Source: NPR
neuroscience biology
Ebola’s West African Rampage Was Likely Bolstered by a Mutation“What made the recent Ebola outbreak in west Africa so virulent? The virus that seeped across borders and killed more than 11,000 people in the region had at least one genetic mutation...

Ebola’s West African Rampage Was Likely Bolstered by a Mutation

What made the recent Ebola outbreak in west Africa so virulent? The virus that seeped across borders and killed more than 11,000 people in the region had at least one genetic mutation that better equipped it to breach human cells, new research suggests. The startling discovery provides the first evidence that genetic changes likely sped up transmission—and may have made the terrifying disease even more deadly for humans.

[…]

In one study led by 16 researchers at the University of Massachusetts, Broad Institute and elsewhere, genomic analyses pinpointed parts of the Ebola virus that changed during the west African outbreak. One genetic mutation, in particular, appeared to affect a key region of the pathogen where it binds to human cells. Lab tests confirmed the mutated virus could better infiltrate the cells of humans and other primates. The change was so small that earlier computational analyses of genome differences had not picked it up, says Jeremy Luban, a virologist at the University of Massachusetts Medical School who co-authored the study.

Yet this relatively subtle modification may have had an outsized effect. Gaining easier entry into human cells may have enabled the virus to replicate more quickly in a host—and those greater numbers could make it more likely to jump to the next person, Luban says.

Source: scientificamerican.com
ebola virus biology genetics