Oh Yeah, Developmental Biology!

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Heart, heal thyself! No problem, says the zebrafish

(Image: BHF/Dr Jana Koth)image

The future of regenerative medicine is bright: in this case, literally. This image of a stained zebrafish heart glowing with multiple colours is one of the winners of the British Heart Foundation’s annual heart and blood vessel photography competition.

The green staining of the two-day-old heart highlights the cardiomyocytes, the cells of the heart muscle itself. The red and blue-stained areas represent the contractile apparatus, the muscles that keep the heart beating strong.

Zebrafish are useful experimental animals: their genome has been fully sequenced, their bodies are transparent, and their developing embryos are fairly robust. Even more impressively, their hearts have the ability to regenerate after damage. Zebrafish can lose up to 20 per cent of their heart muscle without long-term consequences, as they can repair the damage completely within eight weeks.

Adult mammals lack this superpower. Although some newborn mammals can regenerate damaged heart tissue, this ability vanishes as they mature. During a heart attack, heart muscle cells are deprived of oxygen and they die, leaving scar tissue. “Understanding how zebrafish regenerate [their heart] may one day help victims of heart attacks recover,” says Jana Koth of the BHF Centre of Research Excellence at Oxford University , who took the photograph.

Women in science: How can we plug the leaking pipeline? - 05 June 2013 - New Scientist

Baby dinos pumped their muscles inside the egg

Jun 4

Lemon Shark: Sac to “Stem” 

Shown about halfway through its 12-month gestation period in a computer-generated illustration, a lemon shark—like a human embryo—is literally connected to its mother via an umbilical cord attached to a placenta. But it wasn’t always so.

Until about three months in the womb, baby sharks feed off a yolk sac. Once the embryo has depleted the yolk, the collapsed sac settles against the womb wall and shoots blood vessels into the wall, tapping into the mother’s circulatory system.

By the time the embryo is six months old (pictured), it has a sense of smell 10,000 times sharper than a human’s. This and other sensory adaptations—including electro-sensors that detect the faint voltage of other animals—will one day allow the shark to detect even a fin flick hundreds of feet away, according to the National Geographic documentary In the Womb: Extreme Animals.

From the National Geographic (US) and Channel 4 (UK) Documentary Animals in the womb.

Jun 2

The Brains of the Animal Kingdom - WSJ.com

fuckyeahneuroscience:

New research shows that we have grossly underestimated both the scope and the scale of animal intelligence. Primatologist Frans de Waal on memory-champ chimps, tool-using elephants and rats capable of empathy.

Who is smarter: a person or an ape? Well, it depends on the task. Consider Ayumu, a young male chimpanzee at Kyoto University who, in a 2007 study, put human memory to shame. Trained on a touch screen, Ayumu could recall a random series of nine numbers, from 1 to 9, and tap them in the right order, even though the numbers had been displayed for just a fraction of a second and then replaced with white squares.

I tried the task myself and could not keep track of more than five numbers—and I was given much more time than the brainy ape. In the study, Ayumu outperformed a group of university students by a wide margin. The next year, he took on the British memory champion Ben Pridmore and emerged the “chimpion.”

How do you give a chimp—or an elephant or an octopus or a horse—an IQ test? It may sound like the setup to a joke, but it is actually one of the thorniest questions facing science today. Over the past decade, researchers on animal cognition have come up with some ingenious solutions to the testing problem. Their findings have started to upend a view of humankind’s unique place in the universe that dates back at least to ancient Greece.

Jun 1

Down syndrome neurons grown from stem cells show signature problems

neurosciencestuff:

Down syndrome, the most common genetic form of intellectual disability, results from an extra copy of one chromosome. Although people with Down syndrome experience intellectual difficulties and other problems, scientists have had trouble identifying why that extra chromosome causes such widespread effects.

In new research published this week, Anita Bhattacharyya, a neuroscientist at the Waisman Center at UW-Madison, reports on brain cells that were grown from skin cells of individuals with Down syndrome.

“Even though Down syndrome is very common, it’s surprising how little we know about what goes wrong in the brain,” says Bhattacharyya. “These new cells provide a way to look at early brain development.”

The study began when those skin cells were transformed into induced pluripotent stem cells, which can be grown into any type of specialized cell. Bhattacharyya’s lab, working with Su-Chun Zhang and Jason Weick, then grew those stem cells into brain cells that could be studied in the lab.

One significant finding was a reduction in connections among the neurons, Bhattacharyya says. “They communicate less, are quieter. This is new, but it fits with what little we know about the Down syndrome brain.”  Brain cells communicate through connections called synapses, and the Down neurons had only about 60 percent of the usual number of synapses and synaptic activity. “This is enough to make a difference,” says Bhattacharyya. “Even if they recovered these synapses later on, you have missed this critical window of time during early development.”

The researchers looked at genes that were affected in the Down syndrome stem cells and neurons, and found that genes on the extra chromosome were increased 150 percent, consistent with the contribution of the extra chromosome.

However, the output of about 1,500 genes elsewhere in the genome was strongly affected. “It’s not surprising to see changes, but the genes that changed were surprising,” says Bhattacharyya. The predominant increase was seen in genes that respond to oxidative stress, which occurs when molecular fragments called free radicals damage a wide variety of tissues.

“We definitely found a high level of oxidative stress in the Down syndrome neurons,” says Bhattacharyya. “This has been suggested before from other studies, but we were pleased to find more evidence for that. We now have a system we can manipulate to study the effects of oxidative stress and possibly prevent them.”

Down syndrome includes a range of symptoms that could result from oxidative stress, Bhattacharyya says, including accelerated aging. “In  their 40s, Down syndrome individuals age very quickly. They suddenly get gray hair; their skin wrinkles, there is rapid aging in many organs, and a quick appearance of Alzheimer’s disease. Many of these processes may be due to increased oxidative stress, but it remains to be directly tested.”

Oxidative stress could be especially significant, because it appears right from the start in the stem cells. “This suggests that these cells go through their whole life with oxidative stress,” Bhattacharyya adds, “and that might contribute to the death of neurons later on, or increase susceptibility to Alzheimer’s.”

Other researchers have created neurons with Down syndrome from induced pluripotent stem cells, Bhattacharyya notes. “However, we are the first to report this synaptic deficit, and to report the effects on genes on other chromosomes in neurons. We are also the first to use stem cells from the same person that either had or lacked the extra chromosome. This allowed us to look at the difference just caused by extra chromosome, not due to the genetic difference among people.”

The research, published the week of May 27 in the Proceedings of the National Academy of Sciences, was a basic exploration of the roots of Down syndrome. Bhattacharyya says that while she did not intend to explore treatments in the short term, “we could potentially use these cells to test or intelligently design drugs to target symptoms of Down syndrome.”

What the smallest infectious agents reveal about evolution

on-the-origin-of-species:

Impressive proof of evolution and a summary of what evolution is, whether in the short or long term. A great read.

Top tip from the lab:

NEVER accidentally inhale concentrated ammonium hydroxide. It’s like being punched in the brain.

(disclaimer: always seek medical attention, it’s very dangerous and can lead to a coma if enough is inhaled)


Xenopus laevis eggs are two-toned, with the darker half, known as the animal hemisphere, on top to protect the DNA in the egg from UV radiation. The lighter colored, denser half on bottom, known as the vegetal hemisphere, contains the yolk that will nourish the forming embryo.
source pic and more info here

Xenopus laevis eggs are two-toned, with the darker half, known as the animal hemisphere, on top to protect the DNA in the egg from UV radiation. The lighter colored, denser half on bottom, known as the vegetal hemisphere, contains the yolk that will nourish the forming embryo.

source pic and more info here

Stroke patients improve in first stem cell trial.