Here in Australia we have a national ‘youth’ radio station called Triple J, and on sunday nights they play a guy called John Safran – he’s a species of celebrity with a huge polarizing effect. It’s easy to see why, he’s over-cynical, opinionated and specializing in only a few key topics. I quite like him, [...]... Read more »
Peluchette, J., & Karl, K. (2007) The impact of workplace attire on employee self-perceptions. Human Resource Development Quarterly, 18(3), 345-360. DOI: 10.1002/hrdq.1208
Hannover, B., & Kuhnen, U. (2002) "The Clothing Makes the Self" Via Knowledge Activation1. Journal of Applied Social Psychology, 32(12), 2513-2525. DOI: 10.1111/j.1559-1816.2002.tb02754.x
How long does it *really* take water to move through a watershed? Continue reading →... Read more »
McDonnell, J., McGuire, K., Aggarwal, P., Beven, K., Biondi, D., Destouni, G., Dunn, S., James, A., Kirchner, J., Kraft, P.... (2010) How old is streamwater? Open questions in catchment transit time conceptualization, modelling and analysis. Hydrological Processes, 24(12), 1745-1754. DOI: 10.1002/hyp.7796
Kirchner, J., Tetzlaff, D., & Soulsby, C. (2010) Comparing chloride and water isotopes as hydrological tracers in two Scottish catchments. Hydrological Processes, 24(12), 1631-1645. DOI: 10.1002/hyp.7676
Stewart, M., Morgenstern, U., & McDonnell, J. (2010) Truncation of stream residence time: how the use of stable isotopes has skewed our concept of streamwater age and origin. Hydrological Processes, 24(12), 1646-1659. DOI: 10.1002/hyp.7576
As you probably may well know, your lipid profile is of importance for cardiovascular disease. Especially a high cholesterol level is considered to be a risk factor for coronary artery disease. The efficacy of cocoa in reducing blood pressure and other positive effects on cardiovascular risk factors have been discussed on this blog for some [...]
Related posts:A Chocolate Bar A Day Keeps the Doctor Away
How Much Chocolate is good for your Health?
Have Your Dark Chocolate with Green Tea
... Read more »
Lei Jia,, Xuan Liu,, Yong Yi Bai,, Shao Hua Li,, Kai Sun, Chen He,, & Rutai Hui. (2010) Short-term effect of cocoa product consumption on lipid profile: a meta-analysis of randomized controlled trials. Am J Clin Nutr. info:/
When we talk about social networking or contagion effect, we are usually referring to getting good words out about us so that we can engender good will and gain additional customers. In other words, we often focus on positive behavior in the context of social networks. But just as positive behavior can be fostered through [...]... Read more »
Irit Nitzan and Barak Libai. (2010) Social Effects on Customer Retention. Marketing Science Institute Working Paper Series 2010. info:other/10-107
Sci has recently did a post on p53. She finds it to be a fascinating little guy, and it might just become her new obsession. It appears to be everywhere, the little protein behind the scenes making things happen. (Awww, look at it, all hugging the DNA like that. What a cutie!) And one of [...]... Read more »
Feng, Z., Hu, W., Teresky, A., Hernando, E., Cordon-Cardo, C., & Levine, A. (2007) Declining p53 function in the aging process: A possible mechanism for the increased tumor incidence in older populations. Proceedings of the National Academy of Sciences, 104(42), 16633-16638. DOI: 10.1073/pnas.0708043104
The process of gene expression, in which a gene is used as a blueprint to construct a protein, is anything but static. Levels of gene expression for individual genes rise and fall with environmental circumstances, health, injury, and over the course of aging. It's a tremendously complex system, with a lot of feedback loops and switches, but fortunately the cost of analyzing gene expression profiles over a whole genome is falling rapidly. It is now feasible to run hundreds of such profiles over the course of a study. At the same time the tools of analysis are starting to catch up with the amount of data being generated: researchers are able to more rapidly and effectively draw conclusions from the mountainous databases they construct. So, for example, see this study on flies, which compares groups of flies selected for their longevity versus a control group of average length lives. It demonstrates that systematically sweeping the whole genome for changes in gene expression with age is a viable way to evaluate the importance of other lines of research and find new avenues for future study: We evaluated the gene expression profile in young, middle-aged, and old male flies, finding that 530...... Read more »
Sarup P, Sørensen P, & Loeschcke V. (2010) Flies selected for longevity retain a young gene expression profile. Age (Dordrecht, Netherlands). PMID: 20607427
What have people been talking about this week in high energy physics, astrophysics, gravitation, general relativity and quantum gravity?... Read more »
Pakull, M., Soria, R., & Motch, C. (2010) A 300-parsec-long jet-inflated bubble around a powerful microquasar in the galaxy NGC 7793. Nature, 466(7303), 209-212. DOI: 10.1038/nature09168
Pohl, R., Antognini, A., Nez, F., Amaro, F., Biraben, F., Cardoso, J., Covita, D., Dax, A., Dhawan, S., Fernandes, L.... (2010) The size of the proton. Nature, 466(7303), 213-216. DOI: 10.1038/nature09250
There's a little corner of your brain - the anterior cingulate cortex - that's thought to play a role in monitoring errors. The electrical signals that flow from this part of the brain ramp up when the mind is challenged with conflicting information, an effect called 'error response negativity', or ERN. In short, ERN represents that anxious, uneasy feeling you sometimes get when you've made a mistake.
Back in 2009 Michael Inzlicht, at the University of Toronto in Canada, found that religious people had lower ERN compared to non-religious people when trying to complete a challenging task. Religion seemed to be acting as a kind of anxiolytic, a bit like the drug Xanax.
But is it religion, or religious people? Perhaps people who are attracted to religion are just naturally more chilled. Or can you actually reduce anxiety by infusing religious thoughts. In his latest study, he aimed to find out.
He took a bunch of students of varying religious beliefs, and subliminally primed some of them with religious thoughts by making them unscramble sentences with religious content. Others had to unscramble neutral sentences.
Then he got them to do the Stroop Colour Word Test, a challenging test that generates ERN.
Both the religious and non-religious performed equally well. And, unlike Inzlicht's first study, there was no intrinsic difference between the two group's ERN after the neutral prime.
However, for those students that were religious, priming with religious thoughts beforehand reduced their ERN. For atheists, the opposite occurred. Their ERN actually increased if they had been previously exposed to religious messages.
It's not clear why this should be. Perhaps religion makes the religious feel comfortable, while for atheists it sets up an immediate conflict, so heightening their response. Maybe priming with reassuring thoughts about atheism would have the opposite effect:
"Maybe when atheists think about science, and the way our world is organized through that lens, it would offer them the same reassurance," suggests Inzlicht. "The point here is the power of the mind to change external circumstances." Vancouver Sun
It's also worth thinking about the implications of this study. On the face of it, reducing anxiety sounds like a good thing. But, like the sensation of pain, ERN is there for a reason. It's there to tell us when we are going down a blind alley, and to motivate us to stop. A low ERN is linked to pathologies such as autism, obsessive compulsive disorder, and attention-deficit hyperactive disorder (ADHD).
In this light, it's interesting to compare these results with another study earlier this year. This study found that priming with religious thoughts made people work longer to try to complete an impossible task - when the sensible thing to do was to abandon it as a lost cause. What's more, people primed with religion were actually more anxious afterwards, not less!
Michael Inzlicht, & Alexa M. Tullett (2010). Reflecting on God: Religious Primes Can Reduce Neurophysiological Response to Errors Psychological Science : 10.1177/0956797610375451
This article by Tom Rees was first published on Epiphenom. It is licensed under Creative Commons.
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Michael Inzlicht, & Alexa M. Tullett. (2010) Reflecting on God: Religious Primes Can Reduce Neurophysiological Response to Errors. Psychological Science. info:/10.1177/0956797610375451
Francis Nano (University of Victoria, Canada) and coworkers have developed a live bacterial vaccine that is nevertheless safe and effective for dangerous pathogens, with the aid of temperature-sensitive genetic modifications. This news feature was written on July 13, 2010.... Read more »
Duplantis, B. N., Osusky, M., Schmerk, C. L., Ross, D. R., Bosio, C. M., & Nano, F. E. (2010) Essential genes from Arctic bacteria used to construct stable, temperature-sensitive bacterial vaccines. Proceedings of the National Academy of Sciences. DOI: 10.1073/pnas.1004119107
Blackburn, J., Mitchell, M., Blackburn, M., Curtis, A., & Thompson, B. (2010). Evidence of Antibiotic Resistance in Free-Swimming, Top-Level Marine Predatory Fishes Journal of Zoo and Wildlife Medicine, 41 (1), 7-16 DOI: 10.1638/2007-0061.1
This week’s installment of ‘Are Headlines Hogwash’ brings us to an article from Discovery News this past June. Here’s the headline:
ANTIBIOTICS BREEDING ‘SUPER [...]... Read more »
Blackburn, J., Mitchell, M., Blackburn, M., Curtis, A., & Thompson, B. (2010) Evidence of Antibiotic Resistance in Free-Swimming, Top-Level Marine Predatory Fishes. Journal of Zoo and Wildlife Medicine, 41(1), 7-16. DOI: 10.1638/2007-0061.1
Pharmacotherapy effectiveness for the treatment of obesity has been disappointing. Currently available agents tend to have significant adverse effects (i.e. dependency issues for appetite suppressants) or limited weight loss potential (i.e. orlistat). Drug development has also been slowed by fallout from the link of the combination drug phentermine-fenfluramine (Phen-Fen). This combination was linked to serious heart complications including valvular heart disease.Currently available agents in the United StatesphenterminesibutramineorlistatSingle agents under developmentDrugs primarily used for diabetes--exenatide, pramlintide, liraglutideSelective cannabinoid-1 receptor blockers-rimonabantCannabinoid-1 receptor inverse agonists-taranabantSelective 5HT2C serotonin receptor agonists-lorcaserinLipase blockers-cetilistatResearch on the cannabinoid drugs was slowed when the FDA rejected the application of Sanofi Aventis for it's rimonbant drug trade-named Accomplia. The FDA felt that rimonbant had an unsafe psychiatric side effect profile (depression and suicidal ideation) that precluded approval for prescription use.Combination drugs under development(Qnexa) phentermine and topiramate(Contrave) naltrexone and bupropion(Empatic) bupropioin and zonisamideAn injectable combination of leptin and pramlintideI previously posted on Brain Posts some of the data supporting Qnexa and Contrave as effective in promoting weight loss. Qnexa appear particularly promising given the average weight loss of 10.6% of body weight (21 pounds for a 200 pound individual) in the highest dose group. Qnexa has moved to FDA review for approval in the United States.Today, the FDA ruled that Qnexa is effective but raised concerns about the safety of the combination. The FDA panel medical concerns centered around five areas: anxiety, sleep disturbances, depression, increased heart rate and potential effects on the developing fetus.Both individual agents in Qnexa are currently available by prescription (phentermine for weight loss and topiramate for seizures and migraine prophylaxis). But the combination could have unique adverse effects and the demand for weight loss drugs could expose significant numbers of pregnancies to the drug. In the Qnexa trial, participants were required to be taking effective birth control during the study. Despite this requirement, 34 pregnancies resulted in participants. No adverse effects have been noted in 19 pregnancies in the group that have reached term and delivery. Nevertheless, topiramate has been linked to birth defects in animal studies.Qnexa faces further FDA review this week and a scheduled review by non-FDA experts with a decision expected by late October 2010.Given the public health burden of obesity, it is likely there will be continued active interest in advancing pharmacotherapy for obesity. Diet and physical activity remain the key starting points for weight loss, but improved choices in pharmacotherapy have the potential to benefit millions of individuals. Sunset Photo of Weston, Missouri Red Barn Farm Courtesy of Yates PhotographyKlonoff DC, & Greenway F (2008). Drugs in the pipeline for the obesity market. Journal of diabetes science and technology, 2 (5), 913-8 PMID: 19885278... Read more »
No, MR-CoNS isn't some kind of crazy new conservative, it stands for methicillin resistant coagulase-negative staphylococci. CoNS are relatives of the bacterium Staphylococcus aureus (the 'SA' in MRSA), and are common human commensals--they typically live on us and in us without causing disease.
One of the important things, from a health perspective, about CoNS is that many are resistant to methicillin (methicillin resistance is the "MR" in MRSA). In fact, the resistance mechanism, known as the SCCmec gene cassette, is similar to those found in MRSA (SCCmec is a class of similar, yet genetically distinct genetic elements).
A recent paper looked for CoNS in patients admitted to a French hospital. The findings are disturbing: Read the rest of this post... | Read the comments on this post...... Read more »
Barbier, F., Ruppé, E., Hernandez, D., Lebeaux, D., Francois, P., Felix, B., Desprez, A., Maiga, A., Woerther, P., Gaillard, K.... (2010) Methicillin‐Resistant Coagulase‐Negative Staphylococci in the Community: High Homology of SCCmec IVa between and Major Clones of Methicillin‐Resistant . The Journal of Infectious Diseases, 202(2), 270-281. DOI: 10.1086/653483
Two recent studies independently report mutations in the otoferlin (OTOF) gene are the cause of a rare temporary hearing loss caused by a high body temperature.
I have a hearing loss, and if I spot research on deafness when updating papers for my own research (see Footnote of previous post) I often take a peek.
Tonight I learnt that some people [...]... Read more »
Wang, D., Wang, Y., Weil, D., Zhao, Y., Rao, S., Zong, L., Ji, Y., Liu, Q., Li, J., Yang, H.... (2010) Screening mutations of OTOF gene in Chinese patients with auditory neuropathy, including a familial case of temperature-sensitive auditory neuropathy. BMC Medical Genetics, 11(1), 79. DOI: 10.1186/1471-2350-11-79
Marlin, S., Feldmann, D., Nguyen, Y., Rouillon, I., Loundon, N., Jonard, L., Bonnet, C., Couderc, R., Garabedian, E., & Petit, C. (2010) Temperature-sensitive auditory neuropathy associated with an otoferlin mutation: Deafening fever!. Biochemical and Biophysical Research Communications, 394(3), 737-742. DOI: 10.1016/j.bbrc.2010.03.062
Varga, R. (2005) OTOF mutations revealed by genetic analysis of hearing loss families including a potential temperature sensitive auditory neuropathy allele. Journal of Medical Genetics, 43(7), 576-581. DOI: 10.1136/jmg.2005.038612
You’re at the doctors with a suspected infection, but instead of offering penicillin or erythromycin, they prescribe honey. Would you switch toast toppings? Take a honey pill? How about letting the doctor smear medical grade honey over the infected area?
People have been using honey (not mad honey) as medicine since ancient times, but until now [...]... Read more »
It is well known that crops go through a genetic bottleneck at domestication. Due to the founder effect, they typically show a fraction of the genetic diversity found in their wild relatives. Which is bad, but fixable: fixing it is the plant breeder’s job — or part of it anyway. What’s less well known, according [...]... Read more »
Erskine, W., Sarker, A., & Ashraf, M. (2010) Reconstructing an ancient bottleneck of the movement of the lentil (Lens culinaris ssp. culinaris) into South Asia. Genetic Resources and Crop Evolution. DOI: 10.1007/s10722-010-9582-4
Christopher Taylor over at Catalogue of Organisms has a nice post on agglutinated Saccamminid foraminifera, and very recently wrote on the taxonomy and morphology of Pelosina, Pilulina and Technitella, wherein he brought up a fascinating paper on one hell of a bizarre foram: the 'spicule tree', initally mistaken for a gorgonian (sea fan). I'm going to leech off his find as he didn't specifically mention this tree foram in his post. Also, he mentioned Komokians before I did. Meanie. In all seriousness, go read his posts. For the phylogenetically inclined protistologists, the Komokian post is good food for thought.I'm going to slack off a bit this time. For an overview of the huge clade of awesome that is Foraminifera, see my earlier post here; for another tree foram, see Notodendrodes here.Foraminiferans are amazing creatures: some of them can be best described as giant cannibalistic carnivorous wads of sticky reticulated pseudopodia, capable of snaring and devouring small metazoans and Volvox colonies. They have the fastest microtubule growth rates in the eukaryotic kingdom - a whole two orders of magnitude greater than those of animals at a stunning 12µm/s! (animal cells grow microtubules at around 1-15µm/min.) (Bowser & Travis 2002 J Foram Res) Their pseudopodia are themselves capable of shearing flesh in a process so unique it deserved its own name: 'skyllocytosis' (Bowser 1985 J Protozool). Do not screw around with forams. They are scary.Most of them also have shells, but that's a story for some other day. Well, many stories, for many days. Forams are a huge and diverse group.The following specimen belongs to Astrorhizidae, a group of agglutinating forams - meaning their tests are composed of material from the environment, often very selectively picked. As implied by its name, the spicule tree, or Spiculidendron, composes its test entirely out of sponge spicules. Furthermore, this contraption reaches a stunning 60mm (6cm) in height, as a single-celled organism!Plant, animal or protist? A foram tree to shame all foram trees. A giant spicule-covered monster from the Caribbean tropics. (Rützler & Richardson 1996 Biologie)The paper mentions difficulties in determining whether the spicule tree bears a single nucleus or is coenocytic. Presumably, if it was that hard to find (though they had few specimens to work with), it may well be uninucleate like Notodendrodes. This would be quite cool as 6cm is one hell of a giant cell to be supported by a single nucleus. The cytoplasm also contains symbiotic dinoflagellates, making this tree foram even more like an actual tree.Note that this strange monster of a foram was only described in 1996. The age of exploration is far from over.ReferencesRützler, K., & Richardson, S. (1996). The Caribbean spicule tree: a sponge-imitating foraminifer (Astrorhizidae) Bulletin de l'Institut Royal des Sciences Naturelles de Belgique 66 (Suppl.), 143-151Bowser, S. (2002). RETICULOPODIA: STRUCTURAL AND BEHAVIORAL BASIS FOR THE SUPRAGENERIC PLACEMENT OF GRANULORETICULOSAN PROTISTS The Journal of Foraminiferal Research, 32 (4), 440-447 DOI: 10.2113/0320440BOWSER, S. (1985). Invasive Activity of Allogromia Pseudopodial Networks: Skyllocytosis of a Gelatin/Agar Gel The Journal of Eukaryotic Microbiology, 32 (1), 9-12 DOI: 10.1111/j.1550-7408.1985.tb03005.x... Read more »
Rützler, K., & Richardson, S. (1996) The Caribbean spicule tree: a sponge-imitating foraminifer (Astrorhizidae). Bulletin de l'Institut Royal des Sciences Naturelles de Belgique 66 (Suppl.), 143-151. info:/
Bowser, S. (2002) RETICULOPODIA: STRUCTURAL AND BEHAVIORAL BASIS FOR THE SUPRAGENERIC PLACEMENT OF GRANULORETICULOSAN PROTISTS. The Journal of Foraminiferal Research, 32(4), 440-447. DOI: 10.2113/0320440
BOWSER, S. (1985) Invasive Activity of Allogromia Pseudopodial Networks: Skyllocytosis of a Gelatin/Agar Gel. The Journal of Eukaryotic Microbiology, 32(1), 9-12. DOI: 10.1111/j.1550-7408.1985.tb03005.x
A really interesting idea that seems to be growing in popularity is the concept of fluid-based biomarkers from blood, urine, saliva etc, as opposed to invasive tumour biopsies. A recent paper in Cancer Research took a look at this novel...... Read more »
Martin, K., Fournier, M., Reddy, G., & Pardee, A. (2010) A Need for Basic Research on Fluid-Based Early Detection Biomarkers. Cancer Research, 70(13), 5203-5206. DOI: 10.1158/0008-5472.CAN-10-0987
Throughout my life, I’ve often been told (usually by way of consolation) that autistic children are born to intelligent families. One of my two younger brothers has severe autism. I was very young when he was diagnosed, and for a while he was treated as though he had a speech and language disorder. If I [...]... Read more »
Durkin, M., Maenner, M., Meaney, F., Levy, S., DiGuiseppi, C., Nicholas, J., Kirby, R., Pinto-Martin, J., & Schieve, L. (2010) Socioeconomic Inequality in the Prevalence of Autism Spectrum Disorder: Evidence from a U.S. Cross-Sectional Study. PLoS ONE, 5(7). DOI: 10.1371/journal.pone.0011551
Marmorkrebs are difficult beasts. As I’ve mentioned before, there is no species name for them yet, partly because of how people define species. At the practical level, most crayfish are identified by the sex organs of the males (which Marmorkrebs don’t have). At the conceptual level, many people define species by interbreeding populations (which parthenogenetic organisms don’t do).
Birky and colleagues recently proposed a way to define species for parthenogenetic organisms. As near as I can understand it, their argument runs like this.
First, they’re going to define species using DNA. They just think morphology is too subtle and too prone to mislead.
Second, the criteria that they’re going to use to separate species is going to revolve around two key concepts: genetic drift and adaptation to a niche.
For any organism, even parthenogenetic clones like Marmorkrebs, there is a certain probability that mutations will occur each generation. Even when there is no selection pressure for that mutation, the frequency of the mutation in the population will change just due to chance over time, even becoming fixed or eliminated. That’s genetic drift.
Birky and company define a species as a group of organisms that show genetic changes that are too large to be accounted for by drift alone. They argue that this is indicative of a population that has undergone adaptation to a specific ecological niche.
The details of their proposal involve a fair amount of math, which, for the purposes of writing a blog post, I didn’t feel the need to become intimately acquainted with. At first glance, however, this approach seems generally fruitful. They apply their methods to six different asexual groups, and seem to make some headway on defining them. I think they could also apply their approach to sorting defining an asexual species that is derived from sexual ancestors, although they don’t discuss this.
Some potential glitches in their approach are that they effectively rule out the possibility that two species could be created by drift alone, which I think many evolutionary biologist would be uncomfortable with. They also mention briefly the idea of “higher taxa,” but how to define those higher taxa was not laid out nearly as clearly as for species.
But they do provide hope that Marmorkrebs, and many other asexuals, can get recognized as species, as they should be, in my opinion.
(Note: I wrote most of this before learning that there is a paper coming out that should shed some new light on the identity of Marmorkrebs. Stay tuned!)
Birky C, Adams J, Gemmel M, & Perry J. 2010. Using population genetic theory and DNA sequences for species detection and identification in asexual organisms PLoS ONE 5(5): e10609. DOI: 10.1371/journal.pone.0010609... Read more »
Birky C, Adams J, Gemmel M, & Perry J. (2010) Using population genetic theory and DNA sequences for species detection and identification in asexual organisms. PLoS ONE, 5(5). DOI: 10.1371/journal.pone.0010609
In an experiment originally intended to be a control, the Lahav lab has identified a previously unsuspected feature of the p53 response. It turns out that p53 is being activated in normal growing cells all the time. Because the cell cycle of cells in culture is unsynchronized, this activation can only be seen by looking at single cells. Since p53 may be the most studied protein on the planet, discovering something completely new and unexpected about its activities isn’t an everyday event.... Read more »
Loewer, A., Batchelor, E., Gaglia, G., & Lahav, G. (2010) Basal Dynamics of p53 Reveal Transcriptionally Attenuated Pulses in Cycling Cells. Cell, 142(1), 89-100. DOI: 10.1016/j.cell.2010.05.031
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