Lack of Tryptophan Hydroxylase-1 in Mice Results in Gait Abnormalities

The role of peripheral serotonin in nervous system development is poorly understood. Tryptophan hydroxylase-1 (TPH1) is expressed by non-neuronal cells including enterochromaffin cells of the gut, mast cells and the pineal gland and is the rate-limiting enzyme involved in the biosynthesis of peripheral serotonin. Serotonin released into circulation is taken up by platelets via the serotonin transporter and stored in dense granules. It has been previously reported that mouse embryos removed from Tph1-deficient mothers present abnormal nervous system morphology. The goal of this study was to assess whether Tph1-deficiency results in behavioral abnormalities. We did not find any differences between Tph1-deficient and wild-type mice in general motor behavior as tested by rotarod, grip-strength test, open field and beam walk. However, here we report that Tph1 (−/−) mice display altered gait dynamics and deficits in rearing behavior compared to wild-type (WT) suggesting that tryptophan hydroxylase-1 expression has an impact on the nervous system

<i>Tph1</i> (−/−) mice have a normal response to social novelty.

<p><i>Tph1</i> (−/−) mice demonstrate similar responses to a stranger mouse (A) and to a novel mouse (B). The percentage of time that the test mouse spent exploring stranger 1 was comparable to age-matched WT animals (A) and the time that the test mouse spent exploring stranger 2 was comparable to age-matched WT mice (B).</p

Lack of peripheral serotonin does not result in attention impairment.

<p>Ability to learn the association between the stimulus light and reward in WT and Tph1 (−/−) mice showed a strong trend indicating that aged Tph1 (−/−) mice may acquire this association more slowly, however, overtime they demonstrated successful learning across daily sessions (A). Overall, aged mice of both genotypes showed a significant deficit in performance during trials of 1 (**P<0.01) and 2 seconds (*P<0.05) (B).</p

<i>Tph1</i> (−/−) mice demonstrate alterations in gait dynamics.

<p>A stride is comprised of a swing duration (limb in air) and a stance duration (paw in contact with the treadmill belt). The stance is comprised of a brake duration and a propulsion duration. The paw angle is the outward angle that the paw makes relative to the long axis of the mouse during walking. Gait metrics were described previously <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0059032#pone.0059032-Kale1" target="_blank">[21]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0059032#pone.0059032-Hampton1" target="_blank">[45]</a>.</p

SPCIS: Standardized Plant Community with Introduced Status database

The movement of plant species across the globe exposes native communities to new species introductions. While introductions are pervasive, two aspects of variability underlie patterns and processes of biological invasions at macroecological scales. First, only a portion of introduced species become invaders capable of substantially impacting ecosystems. Second, species that do become invasive at one location may not be invasive in others; impacts depend on invader abundance and recipient species and conditions. Accounting for these phenomena is essential to accurately understand the patterns of plant invasion and explain the idiosyncratic results reflected in the literature on biological invasions. The lack of community-level richness and the abundance of data spanning broad scales and environmental conditions have until now hindered our understanding of invasions at a macroecological scale. To address this limitation, we leveraged quantitative surveys of plant communities in the USA and integrated and harmonized nine datasets into the Standardized Plant Community with Introduced Status (SPCIS) database. The database contains 14,056 unique taxa identified within 83,391 sampling units, of which 52.6% have at least one introduced species. The SPCIS database includes comparable information on plant species occurrence, abundance, and native status across the 50 U.S. States and Puerto Rico. SPCIS can be used to answer macro-scale questions about native plant communities and interactions with invasive plants. There are no copyright restrictions on the data, and we ask the users of this dataset to cite this paper, the respective paper(s) corresponding to the dataset sampling design (all references are provided in Data S1: Metadata S1: Class II-B-2), and the references described in Data S1: Metadata S1: Class III-B-4 as applicable to the dataset being utilized.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/175928/1/ecy3947.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/175928/2/ecy3947_am.pd