Cannabinoid exposure during zebra finch sensorimotor vocal learning persistently alters expression of endocannabinoid signaling elements and acute agonist responsiveness

<p>Abstract</p> <p>Background</p> <p>Previously we have found that cannabinoid treatment of zebra finches during sensorimotor stages of vocal development alters song patterns produced in adulthood. Such persistently altered behavior must be attributable to changes in physiological substrates responsible for song. We are currently working to identify the nature of such physiological changes, and to understand how they contribute to altered vocal learning. One possibility is that developmental agonist exposure results in altered expression of elements of endocannabinoid signaling systems. To test this hypothesis we have studied effects of the potent cannabinoid receptor agonist WIN55212-2 (WIN) on endocannabinoid levels and densities of CB₁immunostaining in zebra finch brain.</p> <p>Results</p> <p>We found that late postnatal WIN treatment caused a long-term global disregulation of both levels of the endocannabinoid, 2-arachidonyl glycerol (2-AG) and densities of CB₁immunostaining across brain regions, while repeated cannabinoid treatment in adults produced few long-term changes in the endogenous cannabinoid system.</p> <p>Conclusions</p> <p>Our findings indicate that the zebra finch endocannabinoid system is particularly sensitive to exogenous agonist exposure during the critical period of song learning and provide insight into susceptible brain areas.</p

The Evolutionary Dynamics of the Lion Panthera leo Revealed by Host and Viral Population Genomics

The lion Panthera leo is one of the world's most charismatic carnivores and is one of Africa's key predators. Here, we used a large dataset from 357 lions comprehending 1.13 megabases of sequence data and genotypes from 22 microsatellite loci to characterize its recent evolutionary history. Patterns of molecular genetic variation in multiple maternal (mtDNA), paternal (Y-chromosome), and biparental nuclear (nDNA) genetic markers were compared with patterns of sequence and subtype variation of the lion feline immunodeficiency virus (FIVPle), a lentivirus analogous to human immunodeficiency virus (HIV). In spite of the ability of lions to disperse long distances, patterns of lion genetic diversity suggest substantial population subdivision (mtDNA ΦST = 0.92; nDNA FST = 0.18), and reduced gene flow, which, along with large differences in sero-prevalence of six distinct FIVPle subtypes among lion populations, refute the hypothesis that African lions consist of a single panmictic population. Our results suggest that extant lion populations derive from several Pleistocene refugia in East and Southern Africa (∼324,000–169,000 years ago), which expanded during the Late Pleistocene (∼100,000 years ago) into Central and North Africa and into Asia. During the Pleistocene/Holocene transition (∼14,000–7,000 years), another expansion occurred from southern refugia northwards towards East Africa, causing population interbreeding. In particular, lion and FIVPle variation affirms that the large, well-studied lion population occupying the greater Serengeti Ecosystem is derived from three distinct populations that admixed recently

Laser patterning of GaAs (001) functionalized with alkanethiol self-assembled monolayers

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Ancient, but not recent, population declines have had a genetic impact on alpine yellow-bellied toad populations, suggesting potential for complete recovery

Reduction in population size and local extinctions have been reported for the yellow-bellied toad, Bombina variegata, but the genetic impact of this is not yet known. In this study, we genotyped 200 individuals, using mtDNA cytochrome b and 11 nuclear microsatellites. We investigated fine-scale population structure and tested for genetic signatures of historical and recent population decline, using several statistical approaches, including likelihood methods and approximate Bayesian computation. Five major genetically divergent groups were found, largely corresponding to geography but with a clear exception of high genetic isolation in a highly touristic area. The effective sizes in the last few generations, as estimated from the random association among markers, never exceeded a few dozen of individuals. Our most important result is that several analyses converge in suggesting that genetic variation was shaped in all groups by a 7- to 45-fold demographic decline, which occurred between a few hundred and a few 1000 years ago. Remarkably, only weak evidence supports recent genetic impact related to human activities. We believe that the alpine B. variegata populations should be monitored and protected to stop their recent decline and to prevent local extinctions, with highest priority given to genetically isolated populations. Nonetheless, current genetic variation pattern, being mostly shaped in earlier times, suggests that complete recovery can be achieved. In general, our study is an example of how the potential for recovery should be inferred even under the co-occurrence of population decline, low genetic variation, and genetic bottleneck signals