Tag Archives: biology

Bacteria Communicate Using a Chemical Language

Each person has about 1 trillion human cells and about 10 trillion bacterial cells. In the webcast Bonnie Bassler, Department of Molecular Biology at Princeton University, discusses the chemical language that lets bacteria coordinate defense and mount attacks (quorum sensing). The find has stunning implications for medicine, industry — and our understanding of ourselves.

Bacteria do all sorts of amazing things for us: educating your immune system to keep bad microbes out, they digest our food, they make our vitamins…

An Artificial Nerve Networks

When neurons – brain nerve cells – are grown in culture, they don’t form complex ‘thinking’ networks. Moses, Feinerman and Rotem wondered whether the physical structure of the nerve network could be designed to be more brain-like. To simplify things, they grew a model nerve network in one dimension only – by getting the neurons to grow along a groove etched in a glass plate. The scientists found they could stimulate these nerve cells using a magnetic field (as opposed to other systems of lab-grown neurons that only react to electricity).

Experimenting further with the linear set-up, the group found that varying the width of the neuron stripe affected how well it would send signals. Nerve cells in the brain are connected to great numbers of other cells through their axons (long, thin extensions), and they must receive a minimum number of incoming signals before they fire one off in response. The researchers identified a threshold thickness, one that allowed the development of around 100 axons. Below this number, the chance of a response was iffy, while just a few over this number greatly raised the chance a signal would be passed on.

The scientists then took two thin stripes of around 100 axons each and created a logic gate similar to one in an electronic computer. Both of these ‘wires’ were connected to a small number of nerve cells. When the cells received a signal along just one of the ‘wires,’ the outcome was uncertain; but a signal sent along both ‘wires’ simultaneously was assured of a response. This type of structure is known as an AND gate. The next structure the team created was slightly more complex: Triangles fashioned from the neuron stripes were lined up in a row, point to rib, in a way that forced the axons to develop and send signals in one direction only. Several of these segmented shapes were then attached together in a loop to create a closed circuit. The regular relay of nerve signals around the circuit turned it into a sort of biological clock or pacemaker.

Moses: ‘We have been able to enforce simplicity on an inherently complicated system. Now we can ask, ‘What do nerve cells grown in culture require in order to be able to carry out complex calculations?’ As we find answers, we get closer to understanding the conditions needed for creating a synthetic, many-neuron ‘thinking’ apparatus.’

Full press release

Promoting Bio-Literacy

Wisconsin State Herbarium tries to ‘counteract bio-illiteracy’

“In a past century people could go outside and name the flowers or trees,” said Ken Cameron, the herbarium’s director. “Now you take a kid outside and the most they can say is, ‘It’s a tree.’ If we can get students in and get them excited, then I think we’ve helped to counteract bio-illiteracy.”
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Herbaria are becoming more of a rarity. And the UW-Madison has the third largest collection of any public university in the country, behind the universities of California and Michigan. At many universities, botany has been absorbed into large biology departments, and collections put into storage. That has not happened at UW-Madison.

“The combination of having a botany department and a big herbarium is getting pretty rare,” said David Baum, botany department chairman. “And more and more herbaria are closing or making the decision to move off campus into storage, which has a real negative effect on research.”

The University of Wisconsin-Madison Herbarium, founded in 1849 (the year the University was founded), is a museum collection of dried, labeled plants of state, national and international importance, which is used extensively for taxonomic and ecological research, as well as for teaching and public service. It contains the world’s largest collection of Wisconsin plants, about one-third of its 1,000,000 specimens having been collected within the state. Most of the world’s floras are well represented, and the holdings from certain areas, such as the Upper Midwest, eastern North America and western Mexico, are widely recognized as resources of global significance.

Tardigrades

Tardigrades (commonly known as water bears) have eight legs and are their own phylum on the tree of life. Some can survive temperatures close to absolute zero, temperatures as high as 151 Â°C (303 Â°F), 1,000 times more radiation than any other animal, nearly a decade without water, and even the vacuum of space.

Educating the Biologist of the 21st Century

An Introductory Science Curriculum for 21st Century Biologists by David Botstein (webcast)

At Princeton’s new Lewis-Sigler Institute, Botstein is spearheading an innovative effort at interdisciplinary undergraduate education. Students will take advantage of state of the art laboratories and computers capable of crunching vast amounts of data generated by actual research. Professors will “provide essential fundamental concepts as required, using the just-in-time-principle” – no more of the “learn this now, it will be good for you later” approach, which Botstein likens to hazing. Botstein says there is “lots of overhead in teaching historical and traditional origins” so his students will learn instead “with ideas and technologies of today.” He wants to create a new basic language that will enable his biology students to make sense of the fundamental issues of other disciplines.

Very good look at future of biology education.

Regenerating Neurons in Eyes

The retina, which is located in the back of the eye, has an outer layer of cells that detect light and translate it into electrical signals. It also has inner layers, which process the signals and send them to the brain.

In degenerative disorders like macular degeneration and retinitis pigmentosa, outer-layer cells, called photoreceptors, break down in the early stages of disease, leading to loss of vision. Extensive research has focused on replacing these cells, in an effort to restore sight. In people with advanced disease or blindness, however, the inner cell layers may also break down or become disorganized and need to be rebuilt, says Rose.

“The outer retina is like the CPU, and the inner retina is like the motherboard,” he says. “If I attach a new CPU to a dead motherboard, it won’t do any good, no matter how great a CPU it is.”
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In lower vertebrates like fish and chickens, retinal cells are known to generate new neurons in response to damage, often restoring sight. While mammals do not have the same self-healing capacity, some previous research has suggested that under particular circumstances, mammals’ retinas might be able to generate new neurons.

2,000 Species New to Science from One Island

photo of squat lobster

Photograph by Dr Tin-Yam Chan, University of Keelung

153 scientists from 20 countries fanned out across the remote South Pacific island of Espiritu Santo, examining mountains, forests, caves, reefs, and water for all living organisms. In five months, they collected 10,000 species. Some 2,000 of these may be new to science.

This squat lobster, found in waters 150 meters (492 feet) deep, is one of the new species. Eighty percent of the world’s species remain to be discovered, notes French scientist Philippe Bouchet, one of the expedition’s leaders.

A World of Crabs from One Tiny Island

About 600 of these were crab species. The two-horn box crab is able to crack and peel open snails’ shells using a sharp “tooth” on its right claw to cut open shells and long, slender “fingers” on the left claw to yank out its prey.

How Cells Age

A new study by Harvard Medical School researchers reveals that the biochemical mechanism that makes yeast grow old has a surprising parallel in mice, suggesting it may be a universal cause of aging in all organisms.
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In young organisms, SIRT1 effectively doubles as a gene-expression regulator and a DNA repairer. But when DNA damage accumulates—as it does with age—SIRT1 becomes too busy fixing broken DNA to keep the expression of hundreds of genes in check. This process is so similar to what happens in aging yeast that its discoverers believe it may represent a universal mechanism of aging.

Harvard researchers gain new insight into aging

Aging may be a case of neglect — an absentee landlord at the cellular level that allows gene activity to go awry, according to a study published today.

Scientists have long known that aging causes gene expression to change, and DNA damage to accumulate. But now, research led by Harvard Medical School scientists explains the connection between the two processes in mammals.

The paper, published in the journal Cell, found that a multi-tasking protein called SIRT1 that normally acts as guardian of the genome gets dragged away to DNA fix-it jobs. When the protein abandons its normal post to work as a genetic handyman, order unravels elsewhere in the cell. Genes that are normally under its careful watch begin to flip on.

“What this paper actually implies is that aspects of aging may be reversible,” said David Sinclair, a Harvard Medical School biologist who led the research. “It sounds crazy, but in principle it should be possible to restore the youthful set of genes, the patterns that are on and off.”

The study is just the latest to draw yet more attention to sirtuins, proteins involved in the aging process

Aging is fascinating. By and large people just accept it. We see it happen to those all around us, without exception. But what causes biological aging? It is an interesting area of research.

Single-Celled Giant Provides New Early-Evolution Perspective

Discovery of Giant Roaming Deep Sea Protist Provides New Perspective on Animal Evolution
Biologist Mikhail “Misha” Matz and his colleagues recently discovered the grape-sized protists and their complex tracks on the ocean floor near the Bahamas. DNA analysis confirmed that the giant protist found by Matz and his colleagues in the Bahamas is Gromia sphaerica, a species previously known only from the Arabian Sea.

Matz says the protists probably move by sending leg-like extensions, called pseudopodia, out of their cells in all directions. The pseudopodia then grab onto mud in one direction and the organism rolls that way, leaving a track. Hr says the giant protists’ bubble-like body design is probably one of the planet’s oldest macroscopic body designs, which may have existed for 1.8 billion years.

“I personally think now that the whole Precambrian may have been exclusively the reign of protists,” says Matz. “Our observations open up this possible way of interpreting the Precambrian fossil record.”

He says the appearance of all the animal body plans during the Cambrian explosion might not just be an artifact of the fossil record. There are likely other mechanisms that explain the burst-like origin of diverse multicellular life forms.

Single-Celled Giant Upends Early Evolution

Slowly rolling across the ocean floor, a humble single-celled creature is poised to revolutionize our understanding of how complex life evolved on Earth.

A distant relative of microscopic amoebas, the grape-sized Gromia sphaerica was discovered once before, lying motionless at the bottom of the Arabian Sea. But when Mikhail Matz of the University of Texas at Austin and a group of researchers stumbled across a group of G. sphaerica off the coast of the Bahamas, the creatures were leaving trails behind them up to 50 centimeters (20 inches) long in the mud.

The trouble is, single-celled critters aren’t supposed to be able to leave trails. The oldest fossils of animal trails, called ‘trace fossils’, date to around 580 million years ago, and paleontologists always figured they must have been made by multicellular animals with complex, symmetrical bodies.

The Glove – Engineering Coolness

photo of The Glove - core control

Cool invention helps tired players bounce back

The device, called the Glove and invented by two Stanford biologists, is used by the Niners during games and at practice for players’ health. But its applications are far broader: from treating stroke and heart attack victims to allowing soldiers to remain in the field longer under intense heat.

It’s also a proven athletic performance enhancer – billed as better than steroids without any ill effects.

“We use the Glove primarily for health reasons,” said Dan Garza, the 49ers’ medical director. “But outside of sports, it has potential for a lot of exciting things. This technology is a much more effective way of cooling the core temperature than what we would typically do – misting, fanning, cold towels, fluids.”

The Glove works by cooling the body from inside out, rather than conventional approaches that cool from outside in. The device creates an airtight seal around the wrist, pulls blood into the palm of the hand and cools it before returning it to the heart and to overheated muscles and organs. The palm is the ideal place for rapid cooling because blood flow increases to the hands (and feet and face) as body temperature rises.

“These are natural mammalian radiators,” said Dennis Grahn, who invented the device with Stanford colleague Craig Heller.

Cool, you can buy your own for only $2,000 🙂 (The Glove used to be called Core Control) High resolution image. Related: Research on Reducing Hamstring Injuries – The Science of the Football Swerve – Randomization in Sports – posts on science and athletics