We describe here for the first time the development of mechanosensory organs in a chelicerate, the spider Cupiennius salei. It has been shown previously that the number of external sense organs increases with each moult. While stage 1 larvae do not have any external sensory structures, stage 2 larvae show a stereotyped pattern of touch sensitive 'tactile hairs' on their legs. We show that these mechanosensory organs develop during embryogenesis. In contrast to insects, groups of sensory precursors are recruited from the leg epithelium, rather than single sensory organ progenitors. The groups increase by proliferation, and neural cells delaminate from the cluster, which migrate away to occupy a position proximal to the accessory cells of the sense organ. In addition, we describe the development of putative internal sense organs, which do not differentiate until larval stage 2. We show by RNA interference that, similar to Drosophila, proneural genes are responsible for the formation and subtype identity of sensory organs. Furthermore, we demonstrate an additional function for proneural genes in the coordinated invagination and migration of neural cells during sensory organ formation in the spider.
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http://dx.doi.org/10.1016/j.ydbio.2007.11.003 | DOI Listing |
J Comp Neurol
November 2024
Department of Pathology and Laboratory Medicine, Robert Larner, MD College of Medicine at the University of Vermont, University of Vermont Medical Center, Burlington, Vermont, USA.
One of the most important goals in biomedical sciences is understanding the causal mechanisms of neurodegeneration. A prevalent hypothesis relates to impaired waste clearance mechanisms from the brain due to reported waste aggregation in the brains of Alzheimer patients, including amyloid-β plaques and neurofibrillary tau tangles. Currently, our understanding of the mechanisms by which waste is removed from the brain is only fragmentary.
View Article and Find Full Text PDFMol Phylogenet Evol
February 2025
Department of Entomology, National Museum of Natural History, Smithsonian Institution, 1000 Constitution Avenue NW, Washington, DC 20560, USA.
Tropical wandering spiders (Ctenidae) are a diverse family of cursorial predators whose species richness peaks in the tropics. The phylogeny of Ctenidae has been examined using morphology and Sanger-based sequencing data, but these studies have been limited by taxon sampling and have often recovered low branch support for many intrafamilial phylogenetic relationships. Herein, we present the most extensive phylogenetic sampling of this family using genome-scale data, leveraging museum collections of all ctenid subfamilies from across the world.
View Article and Find Full Text PDFEur J Neurosci
October 2024
Department of Physiology and Biophysics, Dalhousie University, Halifax, NS, Canada.
Acetylcholine esterases (AChEs) are essential enzymes in cholinergic synapses, terminating neurotransmission by hydrolysing acetylcholine. While membrane bound AChEs at synaptic clefts efficiently perform this task, soluble AChEs are less stable and effective, but function over broader areas. In vertebrates, a single gene produces alternatively spliced forms of AChE, whereas invertebrates often have multiple genes, producing both enzyme types.
View Article and Find Full Text PDFJ Venom Anim Toxins Incl Trop Dis
August 2024
El Colegio de la Frontera Sur (ECOSUR), Grupo Académico de Biotecnología Ambiental, Tapachula, Chiapas, Mexico.
Background: Members of the genus Simon, 1891 are categorized as wandering spiders and are part of the family Trechaleidae. The genomics and proteomics of spiders from North America remain uncharacterized. The present study explores for the first time molecular data from the endemic species Medina, 2006, and also presents new data for (Keyserling, 1878), both collected in southern Mexico.
View Article and Find Full Text PDFJ Comp Neurol
April 2023
Department of Biology and Neuroscience, Saint Michael's College, Colchester, Vermont, USA.
Neurodegenerative diseases are among the main causes of death in the United States, leading to irreversible disintegration of neurons. Despite intense international research efforts, cellular mechanisms that initiate neurodegeneration remain elusive, thus inhibiting the development of effective preventative and early onset medical treatment. To identify underlying cellular mechanisms that initiate neuron degeneration, it is critical to identify histological and cellular hallmarks that can be linked to underlying biochemical processes.
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