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  • June 7, 2011
  • 11:24 AM
  • 1,497 views

An Experimental Therapy from the “Bottom Up”

by Rob Mitchum in ScienceLife

By John Easton
Are we flushing away cures? In the last few years, physicians have developed a new respect for what used to be considered waste. Led by a maverick Australian physician, many US doctors have begun to test the curative capacity, when appropriately acquired, prepared and administered, of human excrement.
For once, it’s not the [...]... Read more »

  • June 7, 2011
  • 09:38 AM
  • 1,475 views

Morphological response of songbirds to 100 years of landscape change in North America

by Roger Jovani in Birds and Science

It is generally recognized that pointed wings allow a faster flight than rounded wings and hence, this shape has been favoured in migrating species or subpopulations. On the other side, rounded wings allow more manoeuvrability, being favoured in closed habitats....... Read more »

  • June 7, 2011
  • 09:05 AM
  • 2,709 views

Freeloading caterpillars get in the way of plant-ant mutualism

by Jeremy Yoder in Denim and Tweed

.flickr-photo { }.flickr-framewide { float: right; text-align: left; margin-left: 15px; margin-bottom: 15px; width:100%;}.flickr-caption { font-size: 0.8em; margin-top: 0px; } Cecropia obtusifolia provides food for ants that come and protect it—unless caterpillars get there first. Photo by wallygroom.Imagine you need a team of security guards. To find them, you decide not to place an ad in the local paper or on Craigslist. Instead, you build an apartment complex next to your home, complete with a full-service cafeteria providing free hot meals 24 hours a day. You leave the front doors unlocked, then hope that anyone who shows up to live in the apartments will also keep an eye on your home.

If you took that strategy to protect your assets, you'd have to be crazy. But that's pretty much what ant-protected plants do all the time. They grow hollow structures called domatia, secrete nectar from special structures, and even produce tasty and nutritious "food bodies." Then they wait for ants to move into the domatia, eat the nectar and the food bodies, and hopefully chase away anything that might want to do the plant harm. The crazy thing is, it works.

Well, it mostly works.

One gap in the ant-protection mutualism is the period when an ant-protected plant hasn't grown big enough to support a whole colony of ants. In this early stage, ants won't colonize the plant, but other insects might be quite happy to take the rewards that are already being offered. That's exactly what larvae of the butterfly Pseudocabima guianalis do—they make themselves at home on unprotected ant-plants.

The ant-plant Pseudocabima caterpillars target is Cecropia obtusifolia, a shrubby Central American tree that relies on ants in the genus Azteca for protection. Azteca ants make vicious and well-coordinated bodyguards. Here's video Ed Yong posted last year, showing a bunch of the ants flushing a hapless moth into an ambush.



However, Cecropia saplings can't produce enough food to support a colony of ants until the plants grow to more than a meter tall. What's too little for thousands of ants is a feast for a Pseudocabima caterpillar, however. Each caterpillar builds a silk shelter around a region of the plant that grows food bodies, and settles in to eat. As it grow larger, the caterpillar moves into a domatium near its original shelter, covering the entrance hole with silk. Finally the caterpillar pupates inside the domatium, emerging as an adult to lay eggs on another unprotected Cecropia plant.

Eventually the Cecropia saplings grow large enough to attract ants, who run off the caterpillars. However, as the paper I linked to above describes, the caterpillars seem to be able to resist an ant colony's establishment on the plant—the silk shelters prevent ants from getting to the best sources of food. Cecropia saplings occupied by caterpillars didn't seem to suffer more herbivore damage than ant-protected plants, but they did grow more slowly over the course of several years' observations. Caterpillar-infested Cecropia plants were also more vulnerable to infection by a fungus, which the ants removed quite effectively.

Interestingly, though, caterpillar-infested plants also produced less food than those guarded by ants. This is a point of circumstantial evidence for a new model of mutualism I wrote about earlier this year, in which cheating is reduced or prevented when a host like Cecropia better mutualists help create better rewards. An ant-protected plant can divert more resources to feeding its tenants, so their work rewards itself. However, Pseudocabima caterpillars are glad to take the lower level of rewards that Cecropia plants offer up to all comers.

In other words, if you're going to give out free lunches, you can't really expect everyone who eats to pay you back.

Reference

Roux, O., Céréghino, R., Solano, P.J., & Dejean, A. (2011). Caterpillars and fungal pathogens: Two co-occurring parasites of an ant-plant mutualism. PLoS ONE, 6 : 10.1371/journal.pone.0020538

... Read more »

Roux, O., Céréghino, R., Solano, P.J., & Dejean, A. (2011) Caterpillars and fungal pathogens: Two co-occurring parasites of an ant-plant mutualism. PLoS ONE. info:/10.1371/journal.pone.0020538

  • June 7, 2011
  • 08:00 AM
  • 1,150 views

Tuesday Crustie: Jonah

by Zen Faulkes in NeuroDojo


As I’m in Hawaii today to attend The Crustacean Society meeting, it seems only fitting to feature a species that is, while not new to science, new to Hawaii. This is Albunea bulla, a sand crab. Regular readers might recognize sand crabs as a group close to my heart, because they were the subject of my doctoral research.

But when you read the text of the paper, you could be forgiven for missing the cool story of how the sample that proved this species was found in Hawaiian waters:

Material examined. U.S.A., Hawaii: 200 fathoms (365.8 m), ex opakapaka a.k.a. crimson jobfish (Pristipomoides filamentosus (Valenciennes)) Little Brooks Bank (ca. 24°–24°15’N, 166°45’–167°W), northwestern Hawaiian Islands, coll. Capt. W. Strickland on F/V Fortuna, 11 Apr 2005: 1 male, 17.5 mm cl
(BPBM S12265).
You might suspect something was up when you hit this understated little phrase:

The condition of the present specimen is remarkably good, considering the source(.)
Finally, it sinks in:

(T)he fact that the fish species from which the Hawaiian specimen of A. bulla was removed has been found generally from 90–360 m depth (Allen 1985) suggests that perhaps the crab was eaten at shallower depths and transported intus piscis to the depth at which the fish was caught.
That’s right, they pulled the crab out of the stomach of the fish that ate it!

And, by the way, this proves that anything can sound classy in Latin. Compare:

“intus piscis” — Ooooh, sounds elegant!
“fish guts” — Eeeew, that’s disgusting!

I think in one of my papers, I suggested that one of the big advantages of being a digging species is being hidden from predators.

Apparently, that advantage isn’t as big as I thought.

Reference

Boyko CB. 2010. New records and taxonomic data for 14 species of sand crabs (Crustacea: Anomura: Albuneidae) from localities worldwide. Zootaxa 2555: 49-61... Read more »

Boyko CB. (2010) New records and taxonomic data for 14 species of sand crabs (Crustacea: Anomura: Albuneidae) from localities worldwide. Zootaxa, 49-61. info:/

  • June 6, 2011
  • 09:16 PM
  • 2,284 views

Plesiosaurs, the Beautiful Bottom-Feeders

by Laelaps in Laelaps


In 1821, British geologists Henry De la Beche and William Conybeare presented a bizarre, previously-unknown fossil creature to their colleagues in the Geological Society of London. They called their monster Plesiosaurus. A paddle-legged marine reptile akin to the recently-discovered, shark-shaped animals known as ichthyosaurs, the new animal was cast as “a link between the Ichthyosaurus [...]... Read more »

McHenry CR, Cook AG, & Wroe S. (2005) Bottom-feeding plesiosaurs. Science (New York, N.Y.), 310(5745), 75. PMID: 16210529  

  • June 6, 2011
  • 08:01 PM
  • 1,527 views

The Monarch Butterfly:Emmisary of 3 Nations

by Kimberly Moynahan in Endless Forms Most Beautiful

An exciting thing happened a couple weeks ago. I got email from Donald Davis, one of the leading Monarch Butterfly aficionados in Ontario, asking me if I was the Kimberly Gerson who tagged a monarch butterfly in Whitby Ontario, in September of 2006. If so, he went on to say, my tag had been recovered [...]... Read more »

  • June 6, 2011
  • 06:15 PM
  • 1,289 views

Generating Functional Neurons Directly from Human Fibroblasts

by Michael Long in Phased

Connective tissue cells have been directly converted into functional neurons, avoiding stem cell intermediates likely to be carcinogenic, an important step towards replacing cells lost in Parkinson's disease.... Read more »

Ulrich Pfisterer, Agnete Kirkeby, Olof Torper, James Wood, Jenny Nelander, Audrey Dufour, Anders Björklund, Olle Lindvall, Johan Jakobsson, & Malin Parmar. (2011) Direct conversion of human fibroblasts to dopaminergic neurons. Proceedings of the National Academy of Sciences. info:/10.1073/pnas.1105135108

  • June 6, 2011
  • 06:00 PM
  • 822 views

A Whistle of Surprise

by Diane Kelly in Science Made Cool

A caterpillar with an unusual aural defense mechanism.... Read more »

  • June 6, 2011
  • 04:55 PM
  • 1,676 views

Osteochronology and the Berenstain Bears

by Kristina Killgrove in Powered By Osteons

Actually, Papa Bear, humans are a bit similar to trees.... Read more »

  • June 6, 2011
  • 03:24 PM
  • 1,194 views

How to Recycle Cancer GWAS Data

by Rob Mitchum in ScienceLife

In the 2000s, a new kind of genetic experiment was born: the genome-wide association study, or GWAS. If geneticists could recruit enough people with a particular disease and compare them to an equal number of disease-free controls, they believed GWAS would point the way to common gene variants associated with disease risk and novel biological [...]... Read more »

  • June 6, 2011
  • 02:07 PM
  • 1,099 views

Monitoring your sleep patterns

by Charles Harvey in Charles Harvey - Science Communicator

It’s 3am. The cold light of my computer screen illuminates my face, highlighting the bags that are forming under my eyes and casting disturbing shadows around my bedroom. You might think that I was engaged in something incredibly important to keep me up so late. But no, the truth is, I am unable to sleep and resign myself to touring the bizarre offerings the internet presents only early in the morning.... Read more »

Cajochen C, Frey S, Anders D, Späti J, Bues M, Pross A, Mager R, Wirz-Justice A, & Stefani O. (2011) Evening exposure to a light-emitting diodes (LED)-backlit computer screen affects circadian physiology and cognitive performance. Journal of applied physiology (Bethesda, Md. : 1985), 110(5), 1432-8. PMID: 21415172  

  • June 6, 2011
  • 12:00 PM
  • 1,873 views

Three ways science helps feed us

by Rebecca Nesbit in The birds, the bees and feeding the world

Preventing Foot and Mouth outbreaks, keeping food fresh with plasma and the bacteria in your gut. Video from Becky, Trish and Emma.... Read more »

Charleston, B., Bankowski, B., Gubbins, S., Chase-Topping, M., Schley, D., Howey, R., Barnett, P., Gibson, D., Juleff, N., & Woolhouse, M. (2011) Relationship Between Clinical Signs and Transmission of an Infectious Disease and the Implications for Control. Science, 332(6030), 726-729. DOI: 10.1126/science.1199884  

  • June 6, 2011
  • 11:52 AM
  • 1,319 views

From Diabetes to Pancreatic Cancer

by Sanford- Burnham in Beaker

While studying diabetes, Dr. Pamela Itkin-Ansari and her team made a new discovery about pancreatic cancer – one that could help scientists find new treatments for this devastating disease.... Read more »

Lee SH, Hao E, Kiselyuk A, Shapiro J, Shields DJ, Lowy AM, Levine F, & Itkin-Ansari P. (2011) The Id3/E47 axis mediates cell cycle control in human pancreatic ducts and adenocarcinoma. Molecular cancer research : MCR. PMID: 21498546  

  • June 6, 2011
  • 10:07 AM
  • 2,595 views

Was Spinosaurus a Bison-Backed Dinosaur?

by Brian Switek in Dinosaur Tracking

Spinosaurus and Ouranosaurus were fundamentally different, and they remain among the most bizarre dinosaurs yet discovered... Read more »

Anonymous. (1998) Dino Fins More Like Humps?. Science, 279(5354), 1139-1139. DOI: 10.1126/science.279.5354.1139d  

Bailey, J.B. (1997) Neural Spine Elongation in Dinosaurs: Sailbacks or Buffalo-Backs?. Journal of Paleontology, 71(6), 1124-1146. info:/

  • June 6, 2011
  • 09:21 AM
  • 1,380 views

The pygopodid radiation: diverse diets and the 'pygopodids got there first' hypothesis (gekkotans part X)

by Darren Naish in Tetrapod Zoology

The previous article - part of my now lengthy series on gekkotan squamates (see links below) - provided an introduction to the neat and fascinating near-limbless Australasian gekkotans known as the pygopodids. Disclaimer: the group being discussed here is 'Pygopodidae of tradition', not Pygopodidae as currently formulated. More on this matter later.





One topic that I didn't explore fully in the previous article is pygopodid diversity. These reptiles aren't all samey little generalists; species within the group practise several different lifestyles and foraging behaviours, and the amount of morphological variation present within Pygopodidae is impressive [composite above shows Burton's snake-lizard (l) and Ophidiocephalus (r) at top: both by Stewart Macdonald, used with permission. Common scaly-foot Pygopus lepidopodus below by Peter Woodardlong, from wikipedia]. As we'll see below, it may in fact be that pygopodids evolved and diversified early enough to 'beat' a far larger, far more widespread group of squamates - snakes - into the occupation of several ecological roles. Read the rest of this post... | Read the comments on this post...... Read more »

  • June 6, 2011
  • 07:00 AM
  • 1,850 views

June 6, 2011

by Erin Campbell in HighMag Blog

The human body is amazing, but cannot hold a candle to many organisms when it comes to limb regeneration. Zebrafish are able to regenerate amputated fins, including the sensory axons in the fin that sense touch. Today’s image is from a paper discussing the signals required for this process.
... Read more »

  • June 6, 2011
  • 06:30 AM
  • 1,434 views

Counting phosphorylations: one, two, many…

by Becky in It Takes 30

Jeremy Gunawardena’s lab just published a paper that should probably be required reading for anyone in the habit of attempting to measure the relative levels of phosphorylated proteins using Western blots (Prabakaran et al. 2011.  Comparative analysis of Erk phosphorylation suggests a mixed strategy for measuring phospho-form distributions.  Mol. Syst. Biol. 7 482).  If you [...]... Read more »

  • June 6, 2011
  • 06:00 AM
  • 1,755 views

Getting to the root of the Tree of Life

by Wellcome Trust in Wellcome Trust Blog

All organisms on Earth can be mapped onto the phylogenetic ‘Tree of Life’ – with its dividing branches showing how species have evolved through time. At the very base of the tree are three branches, representing the three major domains of life: Bacteria, eukaryotes and Archaea. You’ve almost certainly heard of the first two – [...]... Read more »

  • June 6, 2011
  • 06:00 AM
  • 2,825 views

Trench Fever and Plague in 14th Century France

by Michelle Ziegler in Contagions

The Marseille plague group has been suggesting for some time now that human lice could be a major vector of medieval plague. To test their hypothesis the group devised a multiplex PCR screening method to rapidly screen many aDNA samples for seven pathogens that could cause medieval epidemics, including relapsing fever and trench fever transmitted by human lice. ... Read more »

  • June 5, 2011
  • 03:33 PM
  • 1,615 views

Cambridge BioResource - donating your DNA to science

by Elaine Westwick in The Stuff of Life

Last week I contributed a finger of blood to the Cambridge BioResource project. The DNA extracted from my sample will live in a 96 well plate alongside the genetic material from 10 000 other local donors. Together, we form a smorgasbord of genetically distinct volunteers from which researchers investigating human health can pick and choose. In this post I will explore science behind the resource, discuss the ethics of returning data to participants and reveal what bit of my DNA I'd really like sequenced.With the needle in my arm I spoke to the resource coordinator, Sarah Nutland, who has been involved since the resource was conceived six years ago. My initial questions concerned the nature of the data that would be derived from my sample.  In particular, I was keen to find out if my full genome sequence would be determined, or if analysis was restricted to more sparse genetic regions (genotyping). Until recently, full sequencing would not have been financially viable, but technological advances now make it a question worth asking. I was surprised to learn that no genetic information is initially extracted from the volunteers’ DNA. Instead, sequencing is driven by each scientific project. If a research team are studying a particular region of DNA, then that region is genotyped across the panel of samples. The resulting genetic data is used to pool individuals, along with criteria such as gender, age and disease history. Scientists then have the luxury of choosing research subjects who fit their experimental design perfectly.The power of the resource comes not from the high number of volunteers in each study (typically fewer than 100 people are involved), but from the diversity of the genetic potpourri from which participants can be picked. The bigger the resource, the more likely there will be enough people with the genetic makeup and characteristics required for each investigation. There is a plan to double the number of volunteers, in part by recruiting patients suffering from a range of long term conditions. Links are being made with disease specialists and a recruitment bus will soon swing into action visiting GP surgeries to harvest donations.  It is hoped that the involvement of patients will also inspire donations from their healthy acquaintances, keen to help out.I have always been wary of taking part in clinical trials, valuing my fully functioning biology too much to risk ingesting pharmacological unknowns. But the types of experiments run by the resource are at a much more basal level. They examine the nuts and bolts of molecular biology, acting more as a prelude to the drug discovery process rather than an investigation of nascent drugs themselves. As a result, volunteer participation tends to be straightforward – in many cases blood and a signature are the only requirements. There are experiments  which involve a bigger chunk of time, but participation is always optional. Sarah says that once a volunteer has completed their first study and realise how little is required they are likely to return for another, flush with the glow of donating to a good cause.At this stage in the conversation the needle had been removed and my two-year-old had fallen asleep on my lap. He had been fussed over by the nurses and was now sleeping off a three-pack of custard creams and a beaker of orange juice the size of his daily fluid intake. As he snoozed, Sarah told me how the resource had been set up. The lab she was working in, headed by John Todd, was using genetics to probe the biology of Type 1 Diabetes. The experiments needed human DNA, so lab members and clinical staff rolled up their sleeves. When they needed more they asked colleagues in neighbouring labs. Soon it became clear that collection needed a formal footing and BioResource was born.Ethical considerations underpin the design of the resource and determine which individual studies gain approval. Volunteers are not given any details about their DNA sequence, and only studies where it is ethical to withhold this information are sanctioned.  Even the project researchers can only access data tied to their research subjects, rather than across the whole panel of volunteers.Although no information crucial to the health of each individual is generated, the studies still output genetic data I’d be very interested to learn. For example, a recent paper in Neuropsychologia used the resource to study how differences in the serotonin transporter gene affect the brain’s response to emotionally laden pictures. There are two flavours of the gene’s controller, short and long, your personal combination seems likely to influence how you respond to stress, including your predisposition to depression. Having been touched by the black dog in the past, I’d love to know my serotonin uptake inhibitor type (and I’m not the only one interested). As a rational scientist, I understand that the genetic association is swimming is in caveats and uncertainties, but, on an emotional level, I’d still like to know.According to the paper’s lead author, Elisabeth von dem Hagen, no volunteers requested the information, and she points out that the pseudo-anonymisation procedure means that the scientists themselves were ignorant. “As researchers, we were blind to an individual’s genotype. It was only once we had completed data collection for the study that the BioResource panel released genotype information to enable us to complete the analysis. At that stage, participants have been anonymised by number so the genotype never gets released together with a name. This procedure also ensures that our data collection and analysis is blind to genotype and can’t be biased in any way.”As the cost of sequencing falls, I wonder if a point will be reached when it will make financial, logistical and scientific sense to read full genome sequences, rather than running genotyping each time a study is initiated. However, the ethical issues that the resource now neatly side steps will then be unavoidable – what to do with actionable genetic liabilities uncovered along the way. Perhaps by then there will be parallel advances in clinical genetics and everyone, not just those volunteering for studies, will be having their DNA sequenced.The project has a very Cambridge focus – you need to live near the city not only to donate but also to exploit the resource, physical proximity of subject and researcher being key. (Although if you can’t face battling with hospital parking spaces they will send a nurse to you). The metropolis that is Addenbrookes is very much the beating heart of the resource. DNA sequencing takes place on the site, many of the research groups are based there and Addenbrooke’s staff still make up a significant fraction of volunteers.Due to the project’s success, bioresource envy is widespread, and Oxford and London are looking to start similar banks. Each would encompass volunteers and researchers from their immediate locality and the three centres could pool samples to enable work on rarer genetic variants.If you live in the Cambridge area then take the time to visit the BioResource website and browse the wonderful science it sustains. Consider supporting basic medical research yourself - the commitment is small and, at some future point, you may benefit from discoveries made possible by your own unique contribution.von dem Hagen EA, Passamonti L, Nutland S, Sambrook J, & Calder AJ (2011). The serotonin transporter gene polymorphism and the effect of baseline on amygdala resp... Read more »

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