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The morphological transformation of the pectoral/shoulder girdle is fundamental to the water-to-land transition in vertebrate evolution. Although previous studies have resolved the embryonic origins of tetrapod shoulder girdles, those of fish pectoral girdles remain uncharacterized, creating a gap in the understanding of girdle transformation mechanisms from fish to tetrapods. Here, we identify the embryonic origins of the zebrafish pectoral girdle, including the cleithrum as an ancestral girdle element lost in extant tetrapods. Our combinatorial approach of photoconversion and genetic lineage tracing demonstrates that cleithrum development combines four adjoining embryonic populations. A comparison of these pectoral girdle progenitors with extinct and extant vertebrates highlights that cleithrum loss, indispensable for neck evolution, is associated with the disappearance of its unique developmental environment at the head/trunk interface. Overall, our study establishes an embryological framework for pectoral/shoulder girdle formation and provides evolutionary trajectories from their origin in water to diversification on land. The embryonic origins of the pectoral girdle in fish remain unexplored. Here they show that the zebrafish pectoral girdle develops as an amalgam of four distinct cell populations. [ABSTRACT FROM AUTHOR]

Background: Understanding stand dynamics is essential for predicting future wood supply and associated ecosystem services for sustainable forest management. The dynamics of natural stands can be characterized by agedependent growth and yield models. However, dynamics in managed stands appear somewhat different from that of natural stands, especially with difficulties in explaining the phenomenon of post-thinning overcompensation, based upon some long-term observations. Though overcompensation is an ideal outcome for the forest sector, it had been largely treated as an outlier and thus ignored or dismissed as "out-of-the-ordinary". Methodology: We developed a life history theory-based, state-dependent model of Tree Adaptive Growth (TAG) to investigate this phenomenon and verified that overcompensation should be a common outcome in postthinning forest stands when the stand growth over time is sigmoid shaped. TAG posits that individual trees will invest proportionately more into growth following thinning because it is evolutionarily adaptive to do so. Results: Our investigation of the model's behavior unearthed diverse stand growth patterns similar to that which is observed in the empirical datasets and predicted by a statistics-based Tree's Compensatory Growth (TreeCG) model. Conclusion: A simple, theory-driven, analytical model, TAG, can reproduce the diverse growth patterns in post-thinning stands and thus assist addressing silviculture-related issues. The model can be applied to various jurisdictions even without detailed regional growth and yield relationships and is capable of incorporating the effects of other time sensitive factors like fertilization, pruning, and climate change. [ABSTRACT FROM AUTHOR]

Brain-derived neurotrophic factor (BDNF) has been proposed as a treatment for neurodegeneration, including diseases of the cerebellum, where BDNF levels or those of its main receptor, TrkB, are often diminished relative to controls, thereby serving as replacement therapy. Experimental evidence indicates that BDNF signaling countered cerebellar degeneration, sensorimotor deficits, or both, in transgenic ATXN1 mice mutated for ataxin-1, Cacna1a knock-in mice mutated for ataxin-6, mice injected with lentivectors encoding RNA sequences against human FXN into the cerebellar cortex, Kcnj6 Wv (Weaver) mutant mice with granule cell degeneration, and rats with olivocerebellar transaction, similar to a BDNF -overexpressing transgenic line interbred with Cacng2 stg mutant mice. In this regard, this study discusses whether BDNF is effective in cerebellar pathologies where BDNF levels are normal and whether it is effective in cases with combined cerebellar and basal ganglia damage., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)