G protein-coupled receptors (GPCRs) are transmembrane receptors that relay signals from the external environment inside the cell, allowing an organism to adapt to its surroundings. They are known to detect a vast array of ligands, including sugars, amino acids, pheromone peptides, nitrogen sources, oxylipins, and light. Despite their prevalence in fungal genomes, very little is known about the functions of filamentous fungal GPCRs. Here we present the first full-genome assessment of fungal GPCRs through characterization of null mutants of all 15 GPCRs encoded by the aflatoxin-producing fungus Aspergillus flavus. All strains were assessed for growth, development, ability to produce aflatoxin, and response to carbon sources, nitrogen sources, stress agents, and lipids. Most GPCR mutants were aberrant in one or more response processes, possibly indicative of cross talk in downstream signaling pathways. Interestingly, the biological defects of the mutants did not correspond with assignment to established GPCR classes; this is likely due to the paucity of data for characterized fungal GPCRs. Many of the GPCR transcripts were differentially regulated under various conditions as well. The data presented here provide an extensive overview of the full set of GPCRs encoded by A. flavus and provide a framework for analysis in other fungal species.

Some Thoughts Concerning Education, Locke's treatise on education, has yet to be fully integrated with his more familiar political and philosophical works. On the surface, there seems to be some tension between Locke's advice on how best to educate the young, and his prescriptions for political legitimacy. The emphasis on consent in the Second Treatise of Government seems to require a parallel emphasis on freedom of thought, but it is the possibility of precisely this sort of freedom that Locke calls into question with a theory of education grounded in the external inculcation of mental habits that control behavior throughout life. This surface tension, however, is dispelled by Locke's theory of knowledge, as it is expressed in the Essay Concerning Human Understanding. The Essay's skepticism with regard to an objective and public knowledge makes clear, first, that education is reducible to indoctrination, and second, that liberty therefore requires the rejection or fundamental reconstitution of what has been learned.