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Horned animals
\"Carefully leveled text and vibrant photographs introduce readers to horned animals such as the kudu, yak, and cape buffalo, and explore how they use their horns to defend themselves against predators. Includes activity, glossary, and index.\"-- Provided by publisher.
Book
A subset of spinal dorsal horn interneurons crucial for gating touch-evoked pain-like behavior
A cardinal, intractable symptom of neuropathic pain is mechanical allodynia, pain caused by innocuous stimuli via low-threshold mechanoreceptors such as Aβ fibers. However, the mechanism by which Aβ fiber-derived signals are converted to pain remains incompletely understood. Here we identify a subset of inhibitory interneurons in the spinal dorsal horn (SDH) operated by adeno-associated viral vectors incorporating a neuropeptide Y promoter (AAV-NpyP⁺) and show that specific ablation or silencing of AAV-NpyP⁺ SDH interneurons converted touch-sensing Aβ fiber-derived signals to morphine-resistant pain-like behavioral responses. AAV-NpyP⁺ neurons received excitatory inputs from Aβ fibers and transmitted inhibitory GABA signals to lamina I neurons projecting to the brain. In a model of neuropathic pain developed by peripheral nerve injury, AAV-NpyP⁺ neurons exhibited deeper resting membrane potentials, and their excitation by Aβ fibers was impaired. Conversely, chemogenetic activation of AAV-NpyP⁺ neurons in nerve-injured rats reversed Aβ fiber-derived neuropathic pain-like behavior that was shown to be morphine-resistant and reduced pathological neuronal activation of superficial SDH including lamina I. These findings suggest that identified inhibitory SDH interneurons that act as a critical brake on conversion of touch-sensing Aβ fiber signals into pain-like behavioral responses. Thus, enhancing activity of these neurons may offer a novel strategy for treating neuropathic allodynia.
Journal Article
Activo vs. Pasivo: La arquitectura de los cuatro modos
Este artículo tiene como objetivo establecer una nueva catalogación de arquitecturas a partir de su forma de gestionar el clima con el fin de resituar la gestión climática del espacio y el papel de su habitante como material fundamental del proyecto arquitectónico. En un recorrido que sigue las investigaciones sobre las cualidades térmicas en los edificios de Lisa Heschong, pasando por los planteamientos sobre la pérdida de relación con el clima de Eva Horn, para finalmente complementar los modos de gestión climática propuestos por Reyner Banham. Se desarrollan ejemplos de los cuatro modos en su estado puro: Retardante, Hermético, Selectivo y Regenerativo; separándolos conceptualmente para incorporarlos como material arquitectónico de una manera necesariamente combinada. Y así volver a establecer una relación activa entre las experiencias habitables y la riqueza de las variaciones climáticas.
Journal Article
Pastoralism and Development in Africa
Once again, the Horn of Africa has been in the headlines. And once again the news has been bad: drought, famine, conflict, hunger, suffering and death. The finger of blame has been pointed in numerous directions: to the changing climate, to environmental degradation, to overpopulation, to geopolitics and conflict, to aid agency failures, and more. But it is not all disaster and catastrophe. Many successful development efforts at ‘the margins’ often remain hidden, informal, sometimes illegal; and rarely in line with standard development prescriptions. If we shift our gaze from the capital cities to the regional centres and their hinterlands, then a very different perspective emerges. These are the places where pastoralists live. They have for centuries struggled with drought, conflict and famine. They are resourceful, entrepreneurial and innovative peoples. Yet they have been ignored and marginalised by the states that control their territory and the development agencies who are supposed to help them. This book argues that, while we should not ignore the profound difficulties of creating secure livelihoods in the Greater Horn of Africa, there is much to be learned from development successes, large and small. This book will be of great interest to students and scholars with an interest in development studies and human geography, with a particular emphasis on Africa. It will also appeal to development policy-makers and practitioners.
eBook
Neurodegeneration in the Spinal Ventral Horn Prior to Motor Impairment in Cervical Spondylotic Myelopathy
Remote gray matter pathology has been suggested rostral to the compression site in cervical spondylotic myelopathy (CSM). We therefore assessed neurodegeneration in the gray matter ventral and dorsal horns. Twenty patients with CSM and 18 healthy subjects underwent a high-resolution structural and diffusion magnetic resonance imaging protocol at vertebra C2/C3. Patients received comprehensive clinical assessments. T2*-weighted data provided cross-sectional area measurements of gray matter ventral and dorsal horns to identify atrophy. At the identical location, mean diffusivity (MD) and fractional anisotropy (FA) determined the microstructural integrity. Finally, the relationships between neurodegeneration occurring in the gray and white matter and clinical impairment were investigated. Patients suffered from mild-to-moderate CSM with mainly sensory impairment. In the ventral horns, cross-sectional area was not reduced (p = 0.863) but MD was increased (p = 0.045). The magnitude of MD changes within the ventral horn was associated with white matter diffusivity changes (MD: p = 0.013; FA: p = 0.028) within the lateral corticospinal tract. In contrast, dorsal horn cross-sectional area was reduced by 16.0% (p < 0.001) without alterations in diffusivity indices, compared with controls. No associations between the magnitude of ventral and dorsal horn neurodegeneration and clinical impairment were evident. Focal cord gray matter pathology is evident remote to the compression site in vivo in CSM patients. Microstructural changes in the ventral horns (i.e., motoneurons) related to corticospinal tract integrity in the absence of atrophy and marked motor impairment. Dorsal horn atrophy corresponded to main clinical representation of sensory impairment. Thus, neuroimaging biomarkers of cord gray matter integrity reveal focal neurodegeneration prior to marked clinical impairment and thus could serve as predictors of ensuing impairment in CSM patients.
Journal Article
Multiple cell types guided by neurocytes orchestrate horn bud initiation in dairy goats
Background
Horn development is a key ruminant trait involving multi-cell type coordination via molecular pathways. This study used scRNA-seq to analyze cellular heterogeneity and fate trajectories during early horn bud niche formation, revealing key gene expression profiles. Combining with hematoxylin–eosin (HE) staining and immunohistochemical analysis, we further verified the asynchronous developmental pathways of key cells in the skin tissue of fetal goat horn bud at induction (embryonic day (E) 50; E50), organogenesis (E60), and cytodifferentiation (E70) stages, and demonstrated the signal transmission routes for the development of early horn buds.
Results
We revealed temporal and spatial differences of the main signal transmission of horn bud development combining with existing literatures. We speculated that multiple cell types under the guidance of nerve cells collaborated on horn bud initiation in dairy goats. In detail, neural cells receive initial horn bud signals, stimulating hair follicle cell degeneration and transmitting to dermal cells, which evolve through intermediates, amplify signals to epithelial cells, and differentiate into mesenchymal cells. Nerve cell branches also trigger neural crest cell production/migration, working with chondrocytes to promote keratinocyte differentiation for horn bud formation. In addition, we further identified the early horn bud developmental specific events, including the screening of biological functions, signaling pathways and key candidate genes.
Conclusions
This study employed scRNA-seq to characterize cell fate trajectories and gene expression profiles in goat fetal horn buds. Histological comparisons between hornless and horned fetuses revealed cellular heterogeneity in epithelial, dermal, nerve, and hair follicle cells, with pseudo-time analysis identifying distinct differentiation paths. Dermal and epithelial cell transcriptional dynamics were critical for horn bud initiation (branch 1), supported by immunohistochemistry. Keratinocyte and nerve cell state transitions actively regulated horn development, with asynchronous cell development visualized via immunohistochemistry. Functional enrichment analyses (GO/KEGG) highlighted neural crest development and keratinocyte differentiation pathways, identifying candidate genes (
EGR1
,
ZEB2
,
SFRP2
,
KRT10
,
FMOD
,
CENPW
,
LDB1
,
TWIST1
) involved in horn morphogenesis. These findings advance understanding of goat horn development and genetic determinants.
Journal Article
Neuronal atlas of the dorsal horn defines its architecture and links sensory input to transcriptional cell types
The dorsal horn of the spinal cord is critical to processing distinct modalities of noxious and innocuous sensation, but little is known of the neuronal subtypes involved, hampering efforts to deduce principles governing somatic sensation. Here we used single-cell RNA sequencing to classify sensory neurons in the mouse dorsal horn. We identified 15 inhibitory and 15 excitatory molecular subtypes of neurons, equaling the complexity in cerebral cortex. Validating our classification scheme in vivo and matching cell types to anatomy of the dorsal horn by spatial transcriptomics reveals laminar enrichment for each of the cell types. Neuron types, when combined, define a multilayered organization with like neurons layered together. Employing our scheme, we find that heat and cold stimuli activate discrete sets of both excitatory and inhibitory neuron types. This work provides a systematic and comprehensive molecular classification of spinal cord sensory neurons, enabling functional interrogation of sensory processing.
Journal Article
Beetle horns evolved from wing serial homologs
Understanding how novel complex traits originate is a foundational challenge in evolutionary biology. We investigated the origin of prothoracic horns in scarabaeine beetles, one of the most pronounced examples of secondary sexual traits in the animal kingdom. We show that prothoracic horns derive from bilateral source tissues; that diverse wing genes are functionally required for instructing this process; and that, in the absence of Hox input, prothoracic horn primordia transform to contribute to ectopic wings. Once induced, however, the transcriptional profile of prothoracic horns diverges markedly from that of wings and other wing serial homologs. Our results substantiate the serial homology between prothoracic horns and insects wings and suggest that other insect innovations may derive similarly from wing serial homologs and the concomitant establishment of structure-specific transcriptional landscapes.
Journal Article
Spinal astrocytes in superficial laminae gate brainstem descending control of mechanosensory hypersensitivity
Astrocytes are critical regulators of CNS function and are proposed to be heterogeneous in the developing brain and spinal cord. Here we identify a population of astrocytes located in the superficial laminae of the spinal dorsal horn (SDH) in adults that is genetically defined by Hes5. In vivo imaging revealed that noxious stimulation by intraplantar capsaicin injection activated Hes5+ SDH astrocytes via α1A-adrenoceptors (α1A-ARs) through descending noradrenergic signaling from the locus coeruleus. Intrathecal norepinephrine induced mechanical pain hypersensitivity via α1A-ARs in Hes5+ astrocytes, and chemogenetic stimulation of Hes5+ SDH astrocytes was sufficient to produce the hypersensitivity. Furthermore, capsaicin-induced mechanical hypersensitivity was prevented by the inhibition of descending locus coeruleus–noradrenergic signaling onto Hes5+ astrocytes. Moreover, in a model of chronic pain, α1A-ARs in Hes5+ astrocytes were critical regulators for determining an analgesic effect of duloxetine. Our findings identify a superficial SDH-selective astrocyte population that gates descending noradrenergic control of mechanosensory behavior.Kohro et al. identify a population of astrocytes located in the superficial dorsal horn of adult spinal cord (genetically defined by Hes5) that acts as a gate for locus coeruleus descending noradrenergic control of mechanosensory hypersensitivity.
Journal Article
Structural adaptations to diverse fighting styles in sexually selected weapons
The shapes of sexually selected weapons differ widely among species, but the drivers of this diversity remain poorly understood. Existing explanations suggest weapon shapes reflect structural adaptations to different fighting styles, yet explicit tests of this hypothesis are lacking. We constructed finite element models of the horns of different rhinoceros beetle species to test whether functional specializations for increased performance under speciesspecific fighting styles could have contributed to the diversification of weapon form. We find that horns are both stronger and stiffer in response to species-typical fighting loads and that they perform more poorly under atypical fighting loads, which suggests weapons are structurally adapted to meet the functional demands of fighting. Our research establishes a critical link between weapon form and function, revealing one way male-male competition can drive the diversification of animal weapons.
Journal Article