Quote From Sau Lan Wu, Scientist Who Discovered The #higgsboson. More Quotes Like This One To Inspire

Leopard shark makes world-first switch from sexual to asexual reproduction

A leopard shark in an Australian aquarium has reproduced asexually after being separated from her mate.

It is the first reported case of a shark switching from sexual to asexual or parthenogenetic reproduction and only the third reported case among all vertebrate species.

The leopard shark, Leonie, was captured in the wild in 1999 and introduced to a male shark at the Reef HQ aquarium in Townsville, Queensland, in 2006. Leopard sharks are also known as zebra sharks.

One of the baby sharks born to leopard sharks at Reef HQ aquarium in Townsville, who have produced live young through asexual reproduction. Photograph: Tourism and Events Queensland

Leonie, the world’s first shark known to have switched from sexual to asexual reproduction, at Reef HQ aquarium in Townsville. Photograph: Tourism and Events Queensland

Brain Parasites: part II.

Taenia solium:

The pork tapeworm, Taenia solium, is the most harmful tapeworm in humans. Taenia solium infection is acquired either from human feces that contains Taenia solium eggs or from uncooked pork which contains larval cysts. If larvae are ingested, they mature into adults in the small intestine. This infection type is called taeniasis and is often asymptomatic. If eggs are ingested, the resulting disease is cysticercosis. It gets its name from larval Taenia solium called cysticercus. Both diseases are common in Africa, Asia, South America and Southern Europe. Taeniasis is rare in Muslim countries since people there do not consume pork.

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This year’s Halloween special wraps up the chemistry behind making a mummy: http://wp.me/p4aPLT-26m

Antibiotic resistance discovered in the guts of ancient mummies

The gut bacteria inside 1000-year-old mummies from the Inca Empire are resistant to most of today’s antibiotics, even though we only discovered these drugs within the last 100 years.

“At first we were very surprised,” Tasha Santiago-Rodriguez of California Polytechnic State University in San Louis Opisbo, told the Annual Meeting of the American Society for Microbiology last month.

Her team studied the DNA within the guts of three Incan mummies dating back to between the 10th and 14thcenturies and six mummified people from Italy, from between the 15th and 18th centuries. They found an array of genes that have the potential to resist almost all modern antibiotics, including penicillin, vancomycin and tetracycline.

These ancient genes were largely in microbes whose resistance is problematic today, including Enteroccocus bacteria that can infect wounds and cause urinary tract infections. But they found that many other species, including some harmless ones, carried some of these resistant genes too.

Enterococcus enigma

“When you think about it, almost all these antibiotics are naturally produced, so it makes sense to find antibiotic genes as well,” says Santiago-Rodriguez.

Their finding shows that genes that can confer resistance to antibiotics were relatively widespread hundreds of years before Alexander Fleming discovered penicillin in 1928. “It’s ridiculous to think evolution of antibiotic resistance began when penicillin was discovered,” said team-member Raul Cano, also at California Polytechnic State University, at the meeting while discussing the findings. “It’s been going on for 2 billion years.”

These genes existed long before antibiotics became common, but it is our overuse of these drugs in both people and livestock that caused the superbug resistance to explode worldwide, said Cano.

“This is exciting data,” says Adam Roberts, who studies antibiotic resistance genes at University College London. While it is already well known that antibiotic resistance occurred naturally before people started using antibiotics, this study shows that resistance genes were already within the human gut long before we started using these drugs, he says.

“It begs the question of what was selecting for these genes at this time? Was it the natural production of antibiotics by other bacteria, or were there other, as yet unknown forces at play?” asks Roberts.

We Just Moved One Step Closer to Understanding (and Defeating) Alzheimer’s

Building blocks of memories seen in brains for the first time

Observations of hundreds of neurons in mice suggest that we may divide our memories of where we’ve been into small chunks of experience

At last, we’ve seen what might be the primary building blocks of memories lighting up in the brains of mice.

We have cells in our brains – and so do rodents – that keep track of our location and the distances we’ve travelled. These neurons are also known to fire in sequence when a rat is resting, as if the animal is mentally retracing its path – a process that probably helps memories form, says Rosa Cossart at the Institut de Neurobiologie de la Méditerranée in Marseille, France.

But without a way of mapping the activity of a large number of these individual neurons, the pattern that these replaying neurons form in the brain has been unclear. Researchers have suspected for decades that the cells might fire together in small groups, but nobody could really look at them, says Cossart.

To get a look, Cossart and her team added a fluorescent protein to the neurons of four mice. This protein fluoresces the most when calcium ions flood into a cell – a sign that a neuron is actively firing. The team used this fluorescence to map neuron activity much more widely than previous techniques, using implanted electrodes, have been able to do.

Observing the activity of more than 1000 neurons per mouse, the team watched what happened when mice walked on a treadmill or stood still.

As expected, when the mice were running, the neurons that trace how far the animal has travelled fired in a sequential pattern, keeping track.

These same cells also lit up while the mice were resting, but in a strange pattern. As they reflected on their memories, the neurons fired in the same sequence as they had when the animals were running, but much faster. And rather than firing in turn individually, they fired together in sequential blocks that corresponded to particular fragments of a mouse’s run.

“We’ve been able to image the individual building-blocks of memory,” Cossart says, each one reflecting a chunk of the original episode that the mouse experienced.

Continue Reading.

Neural Pathways by Alexey Kashpersky

Memory Competition

Most of the brain contains cells that no longer divide and renew. However, the dentate gyrus, nestled within the memory-forming centre of the brain (the hippocampus) is one of the few sites where new cells continue to form throughout life. As a person ages, there is an ever-increasing struggle for these new dentate gyrus neurons (coloured pink) to integrate with existing older neurons (green) because the latter already has well-established connections. This may be why learning and memorisation becomes more difficult as a person gets older. Scientists have now found that by temporarily reducing the number of dendritic spines – branches of neurons that form connections with other neurons – in the mature cells, the new cells have a better chance of functionally integrating. Indeed, in live mice, briefly eliminating dendritic spines boosted the number of integrated new neurons, which rejuvenated the hippocampus and improved the animals’ memory precision.

Written by Ruth Williams

Image courtesy of Kathleen McAvoy

Center for Regenerative Medicine, Massachusetts General Hospital, Boston, MA, USA

Copyright held by original authors

Research published in Neuron, September 2016

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Here’s something cool to do with your leftover candy corn – all you have to do is head to space.

Astronauts are allowed to bring special “crew preference” items when they go up in space. NASA astronaut Don Pettit chose candy corn for his five and a half month stint aboard the International Space Station. But these candy corn were more than a snack, Pettit used them for experimentation.

See how he did it: