15 research outputs found

    Brain architecture in the terrestrial hermit crab Coenobita clypeatus (Anomura, Coenobitidae), a crustacean with a good aerial sense of smell

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    <p>Abstract</p> <p>Background</p> <p>During the evolutionary radiation of Crustacea, several lineages in this taxon convergently succeeded in meeting the physiological challenges connected to establishing a fully terrestrial life style. These physiological adaptations include the need for sensory organs of terrestrial species to function in air rather than in water. Previous behavioral and neuroethological studies have provided solid evidence that the land hermit crabs (Coenobitidae, Anomura) are a group of crustaceans that have evolved a good sense of aerial olfaction during the conquest of land. We wanted to study the central olfactory processing areas in the brains of these organisms and to that end analyzed the brain of <it>Coenobita clypeatus </it>(Herbst, 1791; Anomura, Coenobitidae), a fully terrestrial tropical hermit crab, by immunohistochemistry against synaptic proteins, serotonin, FMRFamide-related peptides, and glutamine synthetase.</p> <p>Results</p> <p>The primary olfactory centers in this species dominate the brain and are composed of many elongate olfactory glomeruli. The secondary olfactory centers that receive an input from olfactory projection neurons are almost equally large as the olfactory lobes and are organized into parallel neuropil lamellae. The architecture of the optic neuropils and those areas associated with antenna two suggest that <it>C. clypeatus </it>has visual and mechanosensory skills that are comparable to those of marine Crustacea.</p> <p>Conclusion</p> <p>In parallel to previous behavioral findings of a good sense of aerial olfaction in C. clypeatus, our results indicate that in fact their central olfactory pathway is most prominent, indicating that olfaction is a major sensory modality that these brains process. Interestingly, the secondary olfactory neuropils of insects, the mushroom bodies, also display a layered structure (vertical and medial lobes), superficially similar to the lamellae in the secondary olfactory centers of <it>C. clypeatus</it>. More detailed analyses with additional markers will be necessary to explore the question if these similarities have evolved convergently with the establishment of superb aerial olfactory abilities or if this design goes back to a shared principle in the common ancestor of Crustacea and Hexapoda.</p

    Contribution of Bone Tissue Modulus to Breast Cancer Metastasis to Bone

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    Certain tumors, such as breast, frequently metastasize to bone where they can induce bone destruction. Currently, it is well-accepted that the tumor cells are influenced by other cells and growth factors present in the bone microenvironment that lead to tumor-induced bone disease. Over the past 20 years, many groups have studied this process and determined the major contributing factors; however, these results do not fully explain the changes in gene expression and cell behavior that occur when tumor cells metastasize to bone. More recently, groups studying metastasis from soft tissue sites have determined that the rigidity of the microenvironment, which increases during tumor progression in soft tissue, can regulate tumor cell behavior and gene expression. Therefore, we began to investigate the role of the rigid bone extracellular matrix in the regulation of genes that stimulate tumor-induced bone disease. We found that the rigidity of bone specifically regulates parathyroid hormone-related protein (PTHrP) and Gli2 expression in a transforming growth factor β (TGF-β) and mechanotransduction-dependent mechanism. In this review, we summarize the mechanotransduction signaling pathway and how this influences TGF-β signaling and osteolytic gene expression
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