Category Archives: Education

Fungus-gardening Ant Species Has Given Up Sex Completely

The complete asexuality of a widespread fungus-gardening ant, the only ant species in the world known to have dispensed with males entirely, has been confirmed by a team of Texas and Brazilian researchers.

photo of christian rabeling excavating ants in Brazil

Graduate student Christian Rabeling excavating fungus-farming ant nests in Brasilia.

Most social insects—the wasps, ants and bees—are relatively used to daily life without males. Their colonies are well run by swarms of sterile sisters lorded over by an egg-laying queen. But, eventually, all social insect species have the ability to produce a crop of males who go forth in the world to fertilize new queens and propagate.

Queens of the ant Mycocepurus smithii reproduce without fertilization and males appear to be completely absent, report Christian Rabeling, Ulrich Mueller and their Brazilian colleagues in open access journal PLoS ONE this week.

“Animals that are completely asexual are relatively rare, which makes this is a very interesting ant,” says Rabeling, an ecology, evolution and behavior graduate student at The University of Texas at Austin. “Asexual species don’t mix their genes through recombination, so you expect harmful mutations to accumulate over time and for the species to go extinct more quickly than others. They don’t generally persist for very long over evolutionary time.”

Previous studies of the ants from Puerto Rico and Panama have pointed toward the ants being completely asexual. One study in particular, by Mueller and former graduate student Anna Himler (now at Arizona State University), showed that the ants reproduced in the lab without males, and that no amount of stress induced the production of males.

Scientists believed that specimens of male ants previously collected in Brazil in the 1960s could be males of M. smithii. If males of the species existed, it would suggest that—at least from time to time—the ants reproduce sexually.

Rabeling analyzed the males in question and discovered that they belonged to another closely related (sexually reproducing) species of fungus-farmer, Mycocepurus obsoletus, thus establishing that no males are known to exist for M. smithii. He also dissected reproducing M. smithii queens from Brazil and found that their sperm storage organs were empty.

Taken together with the previous studies of the ants, Rabeling and his colleagues have concluded that the species is very likely to be totally asexual across its entire range, from Northern Mexico through Central America to Brazil, including some Caribbean islands.

As for the age of the species, the scientists estimate the ants could have first evolved within the last one to two million years, a very young species given that the fungus-farming ants evolved 50 million years ago.

Rabeling says he is using genetic markers to study the evolution and systematics of the fungus-gardening ants and this will help determine the date of the appearance and genetic mechanism of asexual reproduction more precisely in the near future.

Full press release

Arduino: Open Source Programmable Hardware

Arduino is an open-source electronics prototyping platform based on flexible, easy-to-use hardware and software. It’s intended for artists, designers, hobbyists, and anyone interested in creating interactive objects or environments.

Arduino can sense the environment by receiving input from a variety of sensors and can affect its surroundings by controlling lights, motors, and other actuators. The microcontroller on the board is programmed using the Arduino programming language and the Arduino development environment.

The boards can be built by hand or purchased preassembled; the software can be downloaded for free. The hardware reference designs (CAD files) are available under an open-source license, you are free to adapt them to your needs.

See the getting started guide to try for yourself.

Printing Bone, Muscle and More

A Pittsburgh-based research team has created and used an innovative ink-jet system to print “bio-ink” patterns that direct muscle-derived stem cells from adult mice to differentiate into both muscle cells and bone cells.

The custom-built ink-jet printer, developed at Carnegie Mellon’s Robotics Institute, can deposit and immobilize growth factors in virtually any design, pattern or concentration, laying down patterns on native extracellular matrix-coated slides (such as fibrin). These slides are then placed in culture dishes and topped with muscle-derived stem cells (MDSCs). Based on pattern, dose or factor printed by the ink-jet, the MDSCs can be directed to differentiate down various cell-fate differentiation pathways (e.g. bone- or muscle-like).

“This system provides an unprecedented means to engineer replacement tissues derived from muscle stem cells,” said Johnny Huard, professor of orthopedic surgery at the University of Pittsburgh School of Medicine and director of the Stem Cell Research Center at Children’s Hospital of UPMC. Huard has long-standing research findings that show how muscle-derived stem cells (MDSCs) from mice can repair muscle in a model for Duchenne Muscular Dystrophy, improve cardiac function following heart failure, and heal large bone and articular cartilage defects.

Weiss and Campbell, along with graduate student Eric Miller, previously demonstrated the use of ink-jet printing to pattern growth factor “bio-inks” to control cell fates. For their current research, they teamed with Phillippi, Huard and biologists of the Stem Cell Research Center at Children’s Hospital to gain experience in using growth factors to control differentiation in populations of MDSCs from mice.

The team envisions the ink-jet technology as potentially useful for engineering stem cell-based therapies for repairing defects where multiple tissues are involved, such as joints where bone, tendon, cartilage and muscle interface. Patients afflicted with conditions like osteoarthritis might benefit from these therapies, which incorporate the needs of multiple tissues and may improve post-treatment clinical outcomes.

The long-term promise of this new technology could be the tailoring of tissue-engineered regenerative therapies. In preparation for preclinical studies, the Pittsburgh researchers are combining the versatile ink-jet system with advanced real-time live cell image analysis developed at the Robotics Institute and Molecular Biosensor and Imaging Center to further understand how stem cells differentiate into bone, muscle and other cell types.

Albatross Chicks Fed Plastic Ocean Pollution by Parents

photo of dead Albatross chick

See more photographs of remains of albatross chicks on the Midway Atoll, a tiny stretch of sand and coral near the middle of the North Pacific.

The nesting babies are fed bellies-full of plastic by their parents, who soar out over the vast polluted ocean collecting what looks to them like food to bring back to their young. On this diet of human trash, every year tens of thousands of albatross chicks die on Midway from starvation, toxicity, and choking.

To document this phenomenon as faithfully as possible, none of the plastic in any of these photographs was moved, placed, manipulated, arranged, or altered in any way. These images depict the untouched stomach contents of baby birds in one of the world’s most remote marine sanctuaries, more than 2000 miles from the nearest continent.

Graduate Engineering and Professional Education @UMichigan

Dilbert’s bosses broke the video link (so I removed it) – not a good sign that they will succeed in my eyes. If they can’t follow basic web usability guidelines it doesn’t make me want to spend time on them.

Engineering TV is a site with lots of good webcasts for engineers: “by engineers for engineers! Focused on technical B2B engineering topics”. In the embedded webcast Dr. Ann Marie Sastry, Director of the Energy Systems Engineering Program at the University of Michigan, discusses a collaboration between GM and the University of Michigan in the Interdisciplinary Graduate Engineering and Professional Education Programs. This is a good example of university and business collaboration.

Prion Proteins, Without Genes, Can Evolve

‘Lifeless’ prion proteins are ‘capable of evolution’

scientists transferred prion populations from brain cells to other cells in culture and observed the prions that adapted to the new cellular environment out-competed their brain-adapted counterparts. When returned to the brain cells, the brain-adapted prions again took over the population.

Charles Weissmann, head of Scripps Florida’s department of infectology who led the study, said: “On the face of it, you have exactly the same process of mutation and adaptive change in prions as you see in viruses.

“This means that this pattern of Darwinian evolution appears to be universally active. “In viruses, mutation is linked to changes in nucleic acid sequence that leads to resistance.

“Now, this adaptability has moved one level down- to prions and protein folding – and it’s clear that you do not need nucleic acid (DNA or RNA) for the process of evolution.”
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He said: “The prion protein is not a clone, it is a quasi-species that can create different protein strains even in the same animal. “The abnormal prion proteins multiply by converting normal prion proteins.

“The implication of Charles Weissmann’s work is that it would be better to cut off that supply of normal prion proteins rather than risk the abnormal prion adapting to a drug and evolving into a new more virulent form.

Engineering a Better Football

The football (soccer ball) for the 2010 FIFA World Cup features completely new, ground-breaking technology. Eight 3-D spherically formed panels are moulded together, harmoniously enveloping the inner carcass. The result is an energetic unit combined with perfect roundness.

Aero grooves create the clearly visible profile on the ball’s surface. The Grip’n’Groove profile circles around the entire ball in an optimal aerodynamic way. The integrated grooves provide unmatched flight characteristics, making this the most stable and most accurate Adidas football. The ground breaking performance features have been confirmed in comprehensive comparison tests at Loughborough University in England and countless checks in wind tunnel and the Adidas football laboratory in Scheinfeld, Germany.

The process, shown in the video, for manufacturing the footballs is way more complicate than I thought it would be.

Microcosm by Carl Zimmer

cover of Microcosm by Carl Zimmer

Microcosm: E. Coli and the New Science of Life by Carl Zimmer is an excellent book. It is full of fascinating information and as usual Carl Zimmer’s writing is engaging and makes complex topics clear.

E-coli keep the level of oxygen low in the gut making the resident microbes comfortable. At any time a person will have as many as 30 strains of E. coli in their gut and it is very rare for someone ever to be free of E. coli. [page 53]

In 1943, Luria and Delbruck published the results that won them the 1969 Nobel Prize in Physiology or Medicine in which they showed that bacteria and viruses pass down their traits using genes (though it took quite some time for the scientific community at large to accept this). [page 70]

during a crisis E coli’s mutation rates could soar a hundred – or even a thousandfold… Normally, natural selection favors low mutation rates, since most mutations are harmful. But in times of stress extra mutations may raise the odds that organisms will hit on a way out of their crisis… [alternatively, perhaps] In times of stress, E coli. may not be able to afford the luxury of accurate DNA repair. Instead, it turns to the cheaper lo-fi polymerases. While they may do a sloppier job, E coli. comes out ahead [page 106]
Hybridization is not the only way foreign DNA got into our cells. Some 3 billion years ago our single-celled ancestors engulfed oxygen-breathing bacteria, which became the mitochondria on which we depend. And, like E. coli, our genomes have taken in virus upon virus. Scientists have identified more than 98,000 viruses in the human genome, along with our mutant vestiges of 150,00 others… If we were to strip out all our transgenic DNA, we would become extinct.

I highly recommend Microcosm, just as I highly recommend Parasite Rex, by Carl Zimmer.

How the Practice and Instruction of Engineering Must Change

Chief Scientist for the Rocky Mountain Institute and MacArthur Fellow, Amory Lovins, describes how small gains in efficiency at the consumption point can trigger gains that are magnitudes larger at higher levels and discusses how engineering must be practiced and taught fundamentally different.

Bionic Vision

Micro Machines and Opto-Electronics on a Contact Lense

Fiction now meets reality with prototype contact lenses developed by Babak Parviz at the University of Washington, in Seattle. Dr. Parviz’s prototype lenses can be used as biosensors to display body chemistry or as a heads up display (HUD). Powered by radio waves and 330 microwatts of power from a loop antenna that picks up power beamed from nearby radio sources, future versions will also be able to harvest power from a cell phone.

In his early 2008 lab tests, rabbits safely wore contact lenses with metal connectors for electronic circuits. The prototype lenses contained an electric circuit as well as red light-emitting diodes for a display. The lenses were tested on rabbits for up to 20 minutes and the animals showed no adverse effects.
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Contact lenses as replacements for smart phone displays — even to monitor blood glucose levels — might best be done while not operating heavy equipment. “The true promise of this research is not just the actual system we end up making, whether it’s a display, a biosensor, or both,” comments Dr. Parviz. “We already see a future in which the humble contact lens becomes a real platform, like the iPhone is today, with lots of developers contributing their ideas and inventions. As far as we’re concerned, the possibilities extend as far as the eye can see, and beyond.”