Greenhouse gas mitigation can reduce sea-ice loss and increase polar  bear persistence pp955 - 958
The dramatic loss of Arctic sea ice with climate change has led to the  prediction of a tipping point beyond which ice loss is irreversible  and polar bear habitat will be catastrophically lost. By contrast,  this study shows a linear relationship between temperature and sea-ice  coverage that overcomes the albedo effect that would cause a tipping  point. As a result, reducing greenhouse gas emissions can have a  positive effect on polar bear populations.
Steven C. Amstrup et al.
doi:10.1038/nature09653
Abstract: http://www.nature.com/nature/journal/v468/n7326/abs/nature09653.html
Article: http://www.nature.com/nature/journal/v468/n7326/full/nature09653.html

Intercalation of a new tier of transcription regulation into an  ancient circuit pp959 - 963
How new phenotypes can be introduced during evolution without losses  of fitness remains largely unexplained at the molecular level. By  comparing the molecular details of a well known process — mating type  determination — across a large diversity of yeast species, the  network rewiring event of the intercalation of a new level of gene  transcription control into an ancient regulatory circuit is shown,  which allowed for the creation of a new phenotype — taking food  availability into account when deciding to mate.
Lauren N. Booth, Brian B. Tuch and Alexander D. Johnson
doi:10.1038/nature09560
Abstract: http://www.nature.com/nature/journal/v468/n7326/abs/nature09560.html
Article: http://www.nature.com/nature/journal/v468/n7326/full/nature09560.html

Noise correlations improve response fidelity and stimulus encoding pp964 - 967
This study introduces a novel recording technique for simultaneously  measuring excitatory and inhibitory conductances of retinal ganglion  cells to show that excitatory and inhibitory inputs are strongly  correlated, thereby cancelling each other. Furthermore, dynamic clamp  is used to introduce these conductance changes into the cell with or  without correlations, and it is found that, as predicted by  theoretical work, correlations significantly increase reliability of  the spiking response.
Jon Cafaro and Fred Rieke
doi:10.1038/nature09570
Abstract: http://www.nature.com/nature/journal/v468/n7326/abs/nature09570.html
Article: http://www.nature.com/nature/journal/v468/n7326/full/nature09570.html

COT drives resistance to RAF inhibition through MAP kinase pathway  reactivation pp968 - 972
Recent data from early clinical trials in melanoma patients carrying  mutations in the B-RAF gene have shown promising results with the B- RAF kinase inhibitor PLX4032; however, many patients eventually  develop resistance to this treatment. Two papers now uncover possible  mechanisms of resistance to PLX4032. One paper shows that upregulation  of MAP3K8 (which encodes COT) can confer resistance of melanoma cells  to B-RAF inhibitors, whereas another paper found that melanomas can  acquire resistance due to mutations of N-RAS or increased expression  of PDGFRβ. Each of these resistance mechanisms seems to apply to at  least some patients on recent PLX4032 trial, whereas, surprisingly, so  far no secondary B-RAF mutations have been observed.
Cory M. Johannessen et al.
doi:10.1038/nature09627
Abstract: http://www.nature.com/nature/journal/v468/n7326/abs/nature09627.html
Article: http://www.nature.com/nature/journal/v468/n7326/full/nature09627.html

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