Post List

  • October 14, 2011
  • 03:18 PM

Who Needs Pheromones When You've Got a Rotten Banana?

by Elizabeth Preston in Inkfish

"The courtship chamber was placed on top of an identical chamber, with the chambers separated by muslin gauze," reports geneticist Yael Grosjean in a Methods section fit for a paperback romance. Then the "perfumed" portion of the experiment began. An aphrodisiac scent was presented on the other side of the muslin gauze. Scientists watched to see whether the subject, a male fruit fly, would be compelled to start courting his partner. To ensure that the female wouldn't influence the results with her responses, she had been recently frozen to death.

(This may seem unromantic, but keep in mind that in another part of the study, the females were headless. It didn't deter the males.)

A male fruit fly displays a scripted set of actions when courting a female, beginning with a buzzy sort of love song and ending with the deposition of his extraordinarily long sperm. Many animals use pheromones, chemical messages wafting through the air, to attract partners. But, Grosjean says, scientists haven't yet found the hardware in a male fruit fly's brain that would respond to pheromones. So what other chemical signals might the fruit fly be sensing when it decides to court a female?

Grosjean's research team identified neurons in male Drosophila melanogaster that detect scent and extend into a part of the brain involved in sexual behaviors. They found that when these neurons weren't working properly, males failed to court (headless) females. Once they knew the neurons were important for courtship behaviors at the brain end, the researchers investigated what was happening at the "nose" end. They exposed the neurons to the smell of fly bodies, both up close and at a distance (as they would be if pheromones were involved). But the neurons didn't respond.

The researchers proceeded to test another 163 odors on the frigid cells until they found a couple of smells that turned them on: phenylacetic acid and phenylacetaldehyde. These aromatic compounds come not from flies, but from plants. (They also lend their honey-like scent to some of the perfumes manufactured by humans.)

These molecules are common in fruit and vegetable matter, including overripe bananas and prickly-pear cactus, two of Drosophila's preferred foods. To understand why mealtime puts fruit flies in the mood for mating, it helps to know that they lay their eggs in their food. (I guarantee this will occur to you the next time you see buzzing visitors inside the pastry display case at your favorite coffee shop.) To a fruit fly, vegetables and fruits are good places to eat, mate, and start a new generation.

It's a surprising evolutionary solution to the problem of helping tiny flying animals find each other and mate. Pheromones work for some other species, but for fruit flies, the smell of a good egg-laying environment might be enough.

The question of whether humans release or detect pheromones, tantalizing though it is, remains unresolved. Maybe scientists would have more luck if they looked for environmental cues humans respond to, rather than molecules released by other humans. I wouldn't expect prickly-pear cactus to be the next hot perfume, but you never know.

Grosjean, Y., Rytz, R., Farine, J., Abuin, L., Cortot, J., Jefferis, G., & Benton, R. (2011). An olfactory receptor for food-derived odours promotes male courtship in Drosophila Nature, 478 (7368), 236-240 DOI: 10.1038/nature10428

... Read more »

Grosjean, Y., Rytz, R., Farine, J., Abuin, L., Cortot, J., Jefferis, G., & Benton, R. (2011) An olfactory receptor for food-derived odours promotes male courtship in Drosophila. Nature, 478(7368), 236-240. DOI: 10.1038/nature10428  

  • October 14, 2011
  • 01:50 PM

The birds and the trees

by GrrlScientist in Maniraptora

SUMMARY: Gray jays hoping to survive and reproduce during Canada's harsh winters must store food in the right kinds of trees ... Read more »

  • October 14, 2011
  • 12:28 PM

For biofuel crops, like any other crop, genetics matter!

by Paul in Energy and the Future

Today I want to mention a couple recent developments on the bioenergy feedstock front.  Specifically, these deal with engineering the genetics of a bioenergy crop with enhanced characteristics for bioenergy. First up, is switchgrass with a gene that prevents flowering … Continue reading →... Read more »

Chuck GS, Tobias C, Sun L, Kraemer F, Li C, Dibble D, Arora R, Bragg JN, Vogel JP, Singh S.... (2011) Overexpression of the maize Corngrass1 microRNA prevents flowering, improves digestibility, and increases starch content of switchgrass. Proceedings of the National Academy of Sciences of the United States of America. PMID: 21987797  

  • October 14, 2011
  • 11:52 AM

A probiotic a day keeps the depression away.

by Brooke N in Smaller Questions

The communication between the gut microbiota and the CNS, also known as the gut-brain axis, is most likely indirect and at the moment not understood, but this evidence implicates its importance in emotional wellbeing. It is also interesting to imagine that these bacteria may be useful for therapeutics in anxiety- or depression- related disorders.... Read more »

Javier A. Bravo, Paul Forsythe, Marianne V. Chew, Emily Escaravage, Hélène M. Savignac, Timothy G. Dinana, John Bienenstockb, and John F. Cryana. (2011) Ingestion of Lactobacillus strain regulates emotional behavior and central GABA receptor expression in a mouse via the vagus nerve . PNAS. info:/

  • October 14, 2011
  • 10:42 AM

The birds and the trees | @GrrlScientist | Punctuated Equilibrium

by GrrlScientist in GrrlScientist

Gray jays hoping to survive and reproduce through Canada's harsh winters must store food in the right kinds of trees ... Read more »

  • October 14, 2011
  • 10:24 AM

Genetic Engineering vs. Breeding

by Matthew DiLeo in The Scientist Gardener

"Many administrators, private and public, have decided that the future of plant breeding lies in genomics, relying on claims that molecular genetics has revolutionized the time frame for product development. ‘Seldom has it been pointed out that it is going to take as long to breed a molecular engineering gene into a successful cultivar as it takes for a natural gene’" - Goodman 2002
Traditional breeding essentially consists of the repeated selection of the best individuals of a plant population over time. This can be accomplished by farmers, hobbyists or professionals and ranges radically in sophistication from the inadvertent selection of genotypes that grow best in a given cultivated environment to massive multi-year statistical studies on large pedigreed families grown in multi-location trials. Regardless of the methods used, breeders are unified in their selection of traits based on phenotype and NOT on genotype (with some limited MAS). Breeders generally don't know (or care) why a plant has a certain trait. They just want it to work. This approach is the strategic opposite of genetic engineering, which aims to first understand the specific mechanism of a given trait first so that it can be consciously and directly modified.

New Sources of Germplasm: Lines, Transgenes, and Breeders*
The end of breeding has been repeatedly and falsely prophesied for going on two decades now - yet even after hundreds and hundreds of millions of dollars of research, only a handful of transgenic traits have been successful. To some extent, it's an unfair comparison as applied genetic engineering has been virtually crippled by regulation. Yet all the same, the above paper by Goodman (2002) does a nice job of outlining all the complications that genetic engineering enthusiasts tend to gloss over in their zeal to take crop improvement beyond breeding.

Far and away, I think the most important reason that genetic engineering has not replaced breeding is that overenthusiastic proponents fail to understand how much of the genetics upon which breeding is built remains unknown. Genotypes can perform radically different in very similar environments and genes can perform radically different within similar genotypes (and of the tens of thousands of genes in any crop, we have a hint of only what a few of them do). Breeding succeeds in the face of these tremendous unknowns because it selects blindly based on phenotypic results.

This distinction between consciously engineering a system and improving it by trial and error (generating many, possibly random iterations and just seeing which works best) is a fundamental distinction seen in many fields from drug discovery to mechanical engineering (to evolving computational cars!). Whether you're trying to improve biological, technological or social systems, iterative selection is best when you don't really understand how your system works - but once you do understand it well enough to make accurate predictions, rational engineering allows massive leaps in what you can accomplish.

Currently, our knowledge of plant biology is nowhere near complete enough to allow wholesale engineering - but it does allow us to make some very small, targeted changes that can occasionally have very big effects (e.g. herbicide and pest resistance). Ten years after Goodman's paper, there is still much that we can hope that genetic engineering will accomplish - but breeding will continue to be the bread and butter of crop adaptation and yield improvement for the foreseeable future.** In 2002, he warned:

"Plagiarizing N.W. Simmonds (1991), we can add MAS, genomics, and possibly even transgenics to the bandwagons we have known. These include (but are certainly not restricted to): induced polyploids, haploids, mutations, overdominance, genetic variances harvest index, high-lysine, small tassels, nitrogen fixation, nitrate reductase, somaclonal variation, bracytic dwarfs, leafy hybrids, precision agriculture, high-oil topcrosses, ag chemical/seed synergy.Simmonds’ observations merit repeating even after more than a decade, “The bandwagon, as it applies to plant breeding, is expensive and damaging. Resources are being diverted from doing genuinely useful jobs to the pursuit of trendy irrelevance; biotechnology is, I think, accelerating the collapse of proper agricultural research." 
Clearly this is an overstatement (now that we're in the future). In particular precision agriculture has gone mainstream and genomics and MAS have been paying dividends. All the same, his ending plea to remember that breeding is the core of crop improvement holds true. Private companies haven't forgotten this (for the few crops and market classes they work on), but our public breeding programs (that cover every other crop) are being rapidly hollowed out and dissolved.

I once heard a nice analogy of genetic engineering vs. breeding.*** Emphasis on genetic engineered "traits" are like drop-in widgets for cars: electric starters, GPS, halogen headlights, etc. But breeding is what shapes the chassis, drivetrain and body. It's great to have all those bells and whistles, but they're more useful on some cars than others...

* Goodman, M.M. (2002). New Sources of Germplasm: Lines, Transgenes, and Breeders Memoria congresso nacional de fitogenetica
** Of course my department, Applied Systems Biology, is one of many groups trying to change this... 
*** Rabobank presentation from Genomics in Business, 2011... Read more »

Goodman, M.M. (2002) New Sources of Germplasm: Lines, Transgenes, and Breeders. Memoria congresso nacional de fitogenetica. info:/

  • October 14, 2011
  • 10:00 AM

Interview with Jonathan Smith, Director of “They Go To Die” Part 1: Background

by Mr Epidemiology in Mr Epidemiology

Over the next week, I have the pleasure of welcoming Jonathan Smith, a recent graduate of the Yale School of Public Health, and a current lecturer in Global Health, to the Blog. Jonathan has been working on a documentary about his research entitled “They Go To Die“, and over the next week, I’ll have the [...]... Read more »

Stuckler, D., Basu, S., McKee, M., & Lurie, M. (2010) Mining and Risk of Tuberculosis in Sub-Saharan Africa. American Journal of Public Health, 101(3), 524-530. DOI: 10.2105/AJPH.2009.175646  

  • October 14, 2011
  • 08:11 AM

Vitamin E may improve gemcitabine effectiveness in pancreatic cancer

by Pieter Droppert in Biotech Strategy Blog

It’s been a bad week for vitamins, especially with the publication of data from the SELECT trial that showed healthy men taking 400 IU/day of Vitamin E had a 17% increased risk of prostate cancer. However, there is some evidence … Continue reading →... Read more »

  • October 14, 2011
  • 08:00 AM

The Benefits of Puppy Love

by Jennifer Gibson, PharmD in Brain Blogger

Pet ownership confers a sense of belonging and acceptance. Many studies have hypothesized that owning and caring for a pet has qualitative psychological and physical benefits, but recent studies are quantifying these advantages. Pet owners have long reported better overall well-being compared to peers without pets, including greater self-esteem, greater conscientiousness, less stress, less negativity, [...]... Read more »

  • October 14, 2011
  • 07:30 AM

Children understand dog language

by United Academics in United Academics

Bark Bark! What’s that Lassie? Marie fell down a well and can’t get out anymore? Take me to her!

Lassie’s owner Timmy always exactly seem to know what his dog was trying to tell him. Now according to researchers at the Eötvös Loránd University in Budapest (Hungary) this might not have been as far-fetched as it might seem. They found that children are much better able than adults to interpret dog barking... Read more »

Péter Pongráczemail, Csaba Molnár, Antal Dóka, & Ádám Miklósi. (2011) Do children understand man's best friend? Classification of dog barks by pre-adolescents and adults. Applied Animal Behaviour Science. info:/

  • October 14, 2011
  • 07:02 AM

Anchoring effects and your salary negotiations

by Rita Handrich in The Jury Room

You often hear about ‘anchoring’ when it comes to making damages requests to jurors. This is not one of those posts, although it tracks with much of the damages research.  This post strikes closer to home—let’s talk about your salary and negotiating a higher income.  You’ll like what these researchers found. Most people hate negotiating [...]

Related posts:Creativity in others makes us uncertain and anxious
This is what a good leader does not look like
Tethered, multi-tasking, or just life?
... Read more »

Thorsteinson, TJ. (2011) Initiating salary discussions with an extreme request: Anchoring effects on initial salary offers. . Journal of Applied Social Psychology, 41(7). info:/

  • October 14, 2011
  • 06:31 AM

When work and home collide, your take on time matters

by Alex Fradera in BPS Occupational Digest

Tension between work and family life is an understandable concern for organisations. As research on how it affects organisational commitment has been equivocal, many researchers are looking for individual differences that may mediate these relationships. A recent article suggests one such difference may relate to how you answer the question: what does the future hold?A research team led by Darren Treadwell drew on the sociological theory of socioemotional selectivity, proposing that a person's motivations are partly guided by their take on the future. If you regard time in your position as expansive or limitless, you possess a deep time perspective, and are more likely to use your time instrumentally to build for the future. A shallow time perspective means you see the end of your tenure as imminent, and are keener to get those rewards you can in the here and now. The team reasoned that these different perspectives may mediate how we feel when work and home collide.The researchers constructed a survey that looked at two facets of organisational commitment. Questions like "This organisation has a great deal of personal meaning for me" covered the affective facet, whereas the more pragmatic one, called 'continuance commitment', established whether for example "Too much in my life would be disrupted if I decided I wanted to leave my organisation". They also included items on time perspective and degree of inter-role conflict - both work-family conflict (WFC) where work clashes with family responsibilities, and its mirror, FWC.Survey data was collected from a sample of 291 staff from a retail firm. For participants with a shallow time perspective, continuance commitment was eroded by higher WFC - they were sensitive to disruptions of their out-of-hours 'good life', and more likely to consider the costs and benefits of shipping out. But the attitude of their deep-time colleagues didn't waver under the same conditions.Affective commitment suffered when WFC was prominent, with participants falling out of love with the job when it hurt their home life. But participants with a deep time perspective also disengaged when family duties impacted work. This seems to reflect a frustration that work ambitions have become difficult to accomplish, leading to disenchantment and a shift to treating the workplace even more instrumentally.This type of research is crucial in revealing the complex shape of important phenomena like inter-role conflict: why it may lead some employees to withdraw into a transactional relationship, and others to question their very presence in the organisation. As workplace engagement remains high on the agenda so these questions will continue to be front of mind.Darren C. Treadwell, Allison B. Duke, Pamela L. Perrewe, Jacob W. Breland, & Joseph M. Goodman (2011). Time May Change Me: The Impact of Future Time Perspective on the Relationship Between Work–Family Demands and Employee Commitment Journal of Applied Social Psychology, 41 (7), 1659-1679 DOI: 10.1111/j.1559-1816.2011.00777.x... Read more »

  • October 14, 2011
  • 06:00 AM

Reconstructing the Black Death

by Suzanne Elvidge in Genome Engineering

The Black Death, an epidemic of the plague, killed 30 million, 50 million, or even as many as 100 million people (around 30-60% of Europe’s population) in the 14th Century, between 1347 and 1351. The plague is caused by Yersinia pestis, which are Gram-negative members of the Enterobacteriaceae family, and researchers have reconstructed the Y pestis genome for the first time.... Read more »

Bos, K., Schuenemann, V., Golding, G., Burbano, H., Waglechner, N., Coombes, B., McPhee, J., DeWitte, S., Meyer, M., Schmedes, S.... (2011) A draft genome of Yersinia pestis from victims of the Black Death. Nature. DOI: 10.1038/nature10549  

  • October 14, 2011
  • 05:47 AM

“Hey you, Fatty! Stop eating so much!” declares UK government

by Stuart Farrimond in Dr Stu's Science Blog

That’s right, being fat is your fault after all. Yesterday, the UK minister for health, Andrew Lansley jabbed his not-too-chubby finger at the overweight far lacking insight into their food addiction. In a rally-call to the 60% of overweight adult Britons, his announced a new ‘national ambition’ is to cut out the hamburgers and go … Continue reading »... Read more »

  • October 14, 2011
  • 04:00 AM

Reduced AMPK and cytosolic iron levels in FH-deficient cells

by Joana Guedes in BHD Research Blog

Mutations in Fumarate Hydratase (FH) cause HLRCC, a kidney cancer syndrome related to BHD. FH is an enzyme involved in the TCA cycle and its deficiency results in the accumulation of fumarate within the cell. This accumulation leads to increased … Continue reading →... Read more »

  • October 14, 2011
  • 02:09 AM


by Janet Kwasniak in Thoughts on thoughts

A recent paper by Zotev and group (citation below) has added another neurofeedback result to the several already on record. The subjects were instructed to contemplate happy memories and attempt to increased the BOLD signal from their left amygdala while real time feedback of the BOLD activity was relayed to them. Effective controls (sham feedback [...]... Read more »

Zotev, V., Krueger, F., Phillips, R., Alvarez, R., Simmons, W., Bellgowan, P., Drevets, W., & Bodurka, J. (2011) Self-Regulation of Amygdala Activation Using Real-Time fMRI Neurofeedback. PLoS ONE, 6(9). DOI: 10.1371/journal.pone.0024522  

  • October 13, 2011
  • 10:05 PM

Lost in a Corn Maze? Developing Epigenetics Based Argonomic Tools in Maize

by Nicole Kelesoglu in E3 Engaging Epigenetics Experts

An amusing local story and description of published work of a plant trait, epigenenomics based biomarker set.... Read more »

Yang S, Wu J, Ziegler T, Yang X, Zayed A, Rajani MS, Zhou D, Basra A, Schachtman D, Peng M.... (2011) Gene expression biomarkers provide sensitive indicators of in planta nitrogen status in Maize. Plant physiology. PMID: 21980173  

  • October 13, 2011
  • 05:32 PM

The platypus: nature’s WTF moment

by NerdyOne in Try Nerdy

Can we just talk about the platypus for a minute? I’m sure some of you are rolling your eyes right now, because everyone knows the basic features of platypuses that make them quirky (yes, “platypuses,” because no one agrees on what the plural form is): just look at them. But what about what you can’t see, and what you might not know?

…They’re venomous? They have how many sex chromosomes?? They might save the world?!? (Not joking about that last one…read on as I cover the basics, and the not-so-basics, of nature’s most beloved WTF moment.)... Read more »

  • October 13, 2011
  • 05:11 PM

Am I single-handedly perpetuating the negative effects of food insecurity?

by Megan Carter in Verdant Nation

CC Image: Franco Folini Now I am not generally one to give money to a pan-handler. If I do give something, it’s generally a snack (usually healthy) if I have one on me. This has been met with different responses: scorn, indifference or thankfulness.  I have offered a few times to go and buy these pan-handlers something to eat or drink but have never been take up on the offer, until today.  I regret though, that I may have contributed to, not helped the problem of food insecurity.  I had stopped off to the side of the sidewalk to grab something from my purse when I was confronted by a shabbily dressed, young man. I had walked to an appointment along Dalhousie Street in Ottawa (for those of you who know where that is) and was on my way back to work.  Since I was stopped, kneeling over my bag, I was a captive audience for this particular individual. He proceeded to tell me all of his problems, from being kicked out of the shelter down the street because of a fist fight, to not having enough to eat. He also assured me that spending money on drugs was not an issue because he doesn’t use them. I was waiting for him to ask me if I could give him money, but that didn’t seem to surface from the avalanche of words spewing from his mouth. I interjected, “can I buy you something to eat?” He replied with “oh yes, yes, please, I’m so hungry.” At this point I should maybe provide a little background on food insecurity. The prevailing definition of food security is “a situation that exists when all people, at all times, have physical, social, and economic access to sufficient, safe and nutritious food that meets their dietary needs and food preferences for an active and healthy life.”  Food security and insecurity are on opposite ends of a continuum. Food insecurity has different stages of severity starting with not being able to buy and eat what one would like. This gets at issues of quality including variety, safety, nutrient content, and the caveat that foods must last and not go to waste. The next stage involves a decrease in quantity which might or might not be accompanied by hunger. Finally, the most severe stage is the complete absence of food intake (going completely without). Food security is a basic human right, but from the 2007-2008 Canadian Community Health Survey, 7.7% (961,000) of Canadian households were food insecure. And keep in mind this is for people with a fixed address, unlike homeless people and those in shelters, so it is likely higher.  I imagine this figure will only climb as our (Canadian) income gap rises and worldwide economic problems deepen; unless of course, our social policies change, but that’s a discussion for another day.      Remember that a key part of food security covers quality – we should have access to healthy, nutritious food.  Being food insecure is related to decreased quality of foods consumed and nutrient inadequacies, which makes intuitive sense.  I regret that although I was providing food in principle, it was not of the nutritious variety.  We went to the nearest restaurant, Garlic Corner, and I said to the guy “get what you like, I’ll pay for it.” He hummed and hawed, something about wanting breakfast down the street because “these guys don’t serve it past noon, and they are really, really slow.”  Then it was he didn’t eat meat but didn’t want any of the vegetarian options. Either the choices at Garlic corner were not healthy enough (which is partially true) or he wanted money instead, of which I am guessing the latter. Anyway, he settled on a Nanaimo cake thing and a red bull. All crap. I mulled all of this over on the remaining walk back to the office. What have I done here? Propagated the problem? Should have I stipulated what he order, ordered it for him, went to a better restaurant, what? What do you think? I tried to help out a fellow human in need, but did I really? Even if I had stipulated what he had ordered, it would have been denigrating.  The other alternative is to ignore street people. While I have done this in the past, I am growing increasingly uncomfortable with it, trying now to at least acknowledge them as people when I walk by – a smile, node, or hello. I don’t mind providing a snack here and there but I’d almost rather do nothing if it means that another red bull or Nanaimo cake gets sold and consumed.     Pilgrim A, Barker M, Jackson A, Ntani G, Crozier S, Inskip H, Godfrey K, Cooper C, Robinson S, & SWS Study Group (2011). Does living in a food insecure household impact on the diets and body composition of young children? Findings from the Southampton Women's Survey Journal of Epidemiology and Community Health, June 7 : 10.1136/jech.2010.125476Kirkpatrick SI, & Tarasuk V (2008). Food insecurity is associated with nutrient inadequacies among Canadian adults and adolescents. The Journal of nutrition, 138 (3), 604-12 PMID: 18287374... Read more »

Pilgrim A, Barker M, Jackson A, Ntani G, Crozier S, Inskip H, Godfrey K, Cooper C, Robinson S, & SWS Study Group. (2011) Does living in a food insecure household impact on the diets and body composition of young children? Findings from the Southampton Women's Survey. Journal of Epidemiology and Community Health. info:/10.1136/jech.2010.125476

  • October 13, 2011
  • 12:19 PM

Evidence Based Point of Care Summaries [1] No “Best” Among the Bests?

by Laika in Laika's Medliblog

For many of today’s busy practicing clinicians, keeping up with the enormous and ever growing amount of medical information, poses substantial challenges [6]. Its impractical to do a PubMed search to answer each clinical question and then synthesize and appraise the evidence. Simply, because busy health care providers have limited time and many questions per day. As [...]... Read more »

Banzi, R., Liberati, A., Moschetti, I., Tagliabue, L., & Moja, L. (2010) A Review of Online Evidence-based Practice Point-of-Care Information Summary Providers. Journal of Medical Internet Research, 12(3). DOI: 10.2196/jmir.1288  

Goodyear-Smith F, Kerse N, Warren J, & Arroll B. (2008) Evaluation of e-textbooks. DynaMed, MD Consult and UpToDate. Australian family physician, 37(10), 878-82. PMID: 19002313  

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