Archive | February 2013

How much pollution are you exposed to? Ask your smartphone!


Exposure assessment in epidemiological studies is a tricky issue, because of the difficulty of constantly tracking people’s activity and location, both of which can affect the exposure to pollution. Researchers at CREAL have shown how using smartphone technology can help to reduce this bias in health effects estimates.

Audrey de Nazelle, a postdoc at Mark Nieuwenhuijsen’s lab who has currently started her own group at the Centre for Environmental Policy, Imperial College in London, used the CalFit smartphone technology to track person-level time, geographic location, and physical activity patterns for improved air pollution exposure assessment. CalFit is a ubiquitous sensing technology developed at UC Berkeley. It consists on using a GPS and an accelerometer in a smartphone to record the location and physical activity of the carrier through energy expenditure and activity tracking algorithms. de Nazelle and her colleagues at CREAL distributed CalFit-equipped smartphones to 36 subjects in Barcelona to obtain information on physical activity and geographic location. This information was then linked to space-time air pollution mapping.

The authors of the paper, published in Environmental Pollution, found that information from CalFit could substantially alter exposure estimates. For instance, travel activities – which wouldn’t have been measurable without the use of the mobiles – accounted on average for 6% of people’s time and 24% of their daily inhaled NO(2).

The potential of this technology for epidemiological studies is enormous. As the authors state, the large number of mobile phone users makes this technology a potential unobtrusive means of enhancing epidemiologic exposure data at low cost. In fact, they are now using it in several epidemiological projects they are involved in, such as the ERC-funded BREATHE study, the EC-funded PHENOTYPE, and the HELIX and EXPOsOMICs studies.


You can read a related interview to de Nazelle here.


de Nazelle A, Seto E, Donaire-Gonzalez D, Mendez M, Matamala J, Nieuwenhuijsen MJ, Jerrett M. Improvingestimates of airpollutionexposurethroughubiquitoussensingtechnologies.EnvironPollut. 2013 Feb 13;176C:92-99

Understanding cannabis

Cannabis has a long history of use as medicine, with historical evidence dating back more than 4000 years.  The potential therapeutic benefits of cannabinoid compounds are huge, but this substance can also have negative effects. A recent paper by Andrés Ozaita and colleagues at the Neurophar laboratory of Rafael Maldonado (CEXS-UPF) has given new insights into the molecular mechanisms that underlie cannabinoid-mediated effects.

Using mice as a model system, the authors had previously shown that blocking the mTOR pathway prevented the amnesic-like effects of THC (a synthetic form of cannabinoid). In the present study, published in the journal Neuropsychopharmacology, they have gone further, proving that the inhibition of the mTOR pathway by the rapamycin derivative temsirolimus, prevents both the anxiogenic- and the amnesic-like effects produced by acute THC, but has no effect on THC-induced anxiolysis, hypothermia, hypolocomotion, and antinociception (lack of pain perception).

Therefore, treatment with temsirolimus could segregate the potentially beneficial effects of cannabinoid agonists, such as the decrease of pain and anxiety, from the negative effects, such as amnesia and an increase of anxiety. As the authors say, these results could help targeting the endocannabinoid system in order to prevent possible side effects.


Puighermanal E, Busquets-Garcia A, Gomis-González M, Marsicano G, Maldonado R, Ozaita A. Dissociation of the Pharmacological Effects of THC by mTOR Blockade. Neuropsychopharmacology. 2013 Jan 28;

From one to billions of cells – new techniques to understand our origins

The transition from single-celled organisms to multicellular animals (metazoans) is one of the most mysterious open questions in biology. To understand the mechanisms involved in this transition it is vital to study the closest unicellular relatives of metazoans. But the analyses on these protists have been severely limited by the lack of transgenesis tools and the difficulty in culturing these simple organisms.

In this article published in Developmental Biology, the Multicellgenome lab the led by Iñaki Ruiz-Trillo at the IBE (CSIC-UPF) presents the first techniques of cell transformation and gene silencing developed in a close relative of metazoans, the ichthyosporean Creolimax fragrantissima. This organism exists both in colonial and amoebal stages. Using transgenesis, the authors here demonstrate that the colony develops from a fully-grown multinucleate syncytium, in which nuclear divisions are strictly synchronized.

blog paper iñaki

Synchronized nuclear division in a growing syncytium prior to the colony formation in ichthyosporeans

They also explain that the genomes of these tiny organisms contain, unexpectedly, several key genes encoding proteins important for metazoan development and multicellularity, such as those involved in cell-cell communication, cell proliferation, cell differentiation, and tissue growth control.

It has been hypothesized that metazoan multicellular development initially occurred through successive rounds of cell division or through cell aggregation. Based on their findings, the authors point to another possible mechanism for the evolution of animal multicellularity: cellularization of a syncytium in which nuclear divisions are synchronized.

Either way, they propose C. fragrantissima as a model organism to investigate, using the transgenesis techniques they have developed, what these ‘multicellular’ genes are doing in protists. Understanding this could indeed provide novel insights into the origin of metazoan multicellularity.


Suga H, Ruiz-Trillo I. Development of ichthyosporeans sheds light on the origin of metazoan multicellularity. Dev Biol. 2013 Jan 17;

%d bloggers like this: