@article {1397, title = {Evolutionary History of Major Chemosensory Gene Families across Panarthropoda}, journal = {Molecular Biology and Evolution}, volume = {37}, year = {2020}, month = {04/08/2020}, pages = {3601-3615}, abstract = {

Chemosensory perception is a fundamental biological process of particular relevance in basic and applied arthropod research. However, apart from insects, there is little knowledge of specific molecules involved in this system, which is restricted to a few taxa with uneven phylogenetic sampling across lineages. From an evolutionary perspective, onychophorans (velvet worms) and tardigrades (water bears) are of special interest since they represent the closest living relatives of arthropods, altogether comprising the Panarthropoda. To get insights into the evolutionary origin and diversification of the chemosensory gene repertoire in panarthropods, we sequenced the antenna- and head-specific transcriptomes of the velvet worm Euperipatoides rowelli and analyzed members of all major chemosensory families in representative genomes of onychophorans, tardigrades, and arthropods. Our results suggest that the NPC2 gene family was the only family encoding soluble proteins in the panarthropod ancestor and that onychophorans might have lost many arthropod-like chemoreceptors, including the highly conserved IR25a receptor of protostomes. On the other hand, the eutardigrade genomes lack genes encoding the DEG-ENaC and CD36-sensory neuron membrane proteins, the chemosensory members of which have been retained in arthropods; these losses might be related to lineage-specific adaptive strategies of tardigrades to survive extreme environmental conditions. Although the results of this study need to be further substantiated by an increased taxon sampling, our findings shed light on the diversification of chemosensory gene families in Panarthropoda and contribute to a better understanding of the evolution of animal chemical senses.

}, keywords = {antenna-specific transcriptome, BITACORA, chemosensory-related proteins, comparative genomics, Onychophora, Tardigrada}, issn = {0737-4038}, doi = {https://doi.org/10.1093/molbev/msaa197}, url = {https://academic.oup.com/mbe/article/37/12/3601/5880555}, author = {Vizueta, Joel and Escuer, Paula and Fr{\'\i}as-L{\'o}pez, Cristina and Guirao-Rico, Sara and Hering, Lars and Mayer, Georg and Rozas, Julio and S{\'a}nchez-Gracia, Alejandro} } @article {1396, title = {Analysis of Pigment-Dispersing Factor Neuropeptides and Their Receptor in a Velvet Worm}, journal = {Frontiers in Endocrinology}, volume = {11}, year = {2020}, month = {12/05/2020}, pages = {1-21}, type = {Research article}, abstract = {

Pigment-dispersing factor neuropeptides (PDFs) occur in a wide range of protostomes including ecdysozoans (= molting animals) and lophotrochozoans (mollusks, annelids, flatworms, and allies). Studies in insects revealed that PDFs play a role as coupling factors of circadian pacemaker cells, thereby controlling rest-activity rhythms. While the last common ancestor of protostomes most likely possessed only one pdf gene, two pdf homologs, pdf-I and pdf-II, might have been present in the last common ancestors of Ecdysozoa and Panarthropoda (Onychophora + Tardigrada + Arthropoda). One of these homologs, however, was subsequently lost in the tardigrade and arthropod lineages followed by independent duplications of pdf-I in tardigrades and decapod crustaceans. Due to the ancestral set of two pdf genes, the study of PDFs and their receptor (PDFR) in Onychophora might reveal the ancient organization and function of the PDF/PDFR system in panarthropods. Therefore, we deorphanized the PDF receptor and generated specific antibodies to localize the two PDF peptides and their receptor in the onychophoran Euperipatoides rowelli. We further conducted bioluminescence resonance energy transfer (BRET) experiments on cultured human cells (HEK293T) using an Epac-based sensor (Epac-L) to examine cAMP responses in transfected cells and to reveal potential differences in the interaction of PDF-I and PDF-II with PDFR from E. rowelli. These data show that PDF-II has a tenfold higher potency than PDF-I as an activating ligand. Double immunolabeling revealed that both peptides are co-expressed in E. rowelli but their respective levels of expression differ between specific cells: some neurons express the same amount of both peptides, while others exhibit higher levels of either PDF-I or PDF-II. The detection of the onychophoran PDF receptor in cells that additionally express the two PDF peptides suggests autoreception, whereas spatial separation of PDFR- and PDF-expressing cells supports hormonal release of PDF into the hemolymph. This suggests a dual role of PDF peptides\—as hormones and as neurotransmitters/neuromodulators\—in Onychophora.

}, keywords = {BRET, E. rowelli, Ecdysozoa, Epac, Onychophora, Panarthropoda, PDF, PDFR}, issn = {1664-2392}, doi = {https://doi.org/10.3389/fendo.2020.00273}, url = {https://www.frontiersin.org/article/10.3389/fendo.2020.00273}, author = {Martin, Christine and Hering, Lars and Metzendorf, Niklas and Hormann, Sarah and Kasten, Sonja and Fuhrmann, Sonja and Werckenthin, Achim and Herberg, Friedrich W. and Stengl, Monika and Mayer, Georg} } @article {1000, title = {Expression of the zinc finger transcription factor Sp6{\textendash}9 in the velvet worm Euperipatoides kanangrensis suggests a conserved role in appendage development in Panarthropoda}, journal = {Development Genes and Evolution}, volume = {230}, year = {2020}, month = {19/05/2020}, pages = {239-245}, abstract = {

The Sp-family genes encode important transcription factors in animal development. Here we investigate the embryonic expression patterns of the complete set of Sp-genes in the velvet worm Euperipatoides kanangrensis (Onychophora), with a special focus on the Sp6\–9 ortholog. In arthropods, Sp6\–9, the ortholog of the Drosophila melanogaster D-Sp1 gene plays a conserved role in appendage development. Our data show that the expression of Sp6\–9 during the development of the velvet worm is conserved, suggesting that the key function of the Sp6\–9 gene dates back to at least the last common ancestor of arthropods and onychophorans and thus likely the last common ancestor of Panarthropoda.

}, keywords = {Appendage development, Arthropod development, Buttonhead, Onychophora, Panarthropoda, Sp1, SP5}, issn = {0949-944X}, doi = {10.1007/s00427-020-00661-w}, url = {http://link.springer.com/10.1007/s00427-020-00661-w}, author = {Janssen, Ralf and Budd, Graham E.} } @article {427, title = {Diversity and evolution of the P450 family in arthropods}, journal = {Insect Biochemistry and Molecular Biology}, volume = {127}, year = {2020}, month = {22/10/2020}, pages = {1-22}, abstract = {

The P450 family (CYP genes) of arthropods encodes diverse enzymes involved in the metabolism of foreign compounds and in essential endocrine or ecophysiological functions. The P450 sequences (CYPome) from 40 arthropod species were manually curated, including 31 complete CYPomes, and a maximum likelihood phylogeny of nearly 3000 sequences is presented. Arthropod CYPomes are assembled from members of six CYP clans of variable size, the CYP2, CYP3, CYP4 and mitochondrial clans, as well as the CYP20 and CYP16 clans that are not found in Neoptera. CYPome sizes vary from two dozen genes in some parasitic species to over 200 in species as diverse as collembolans or ticks. CYPomes are comprised of few CYP families with many genes and many CYP families with few genes, and this distribution is the result of dynamic birth and death processes. Lineage-specific expansions or blooms are found throughout the phylogeny and often result in genomic clusters that appear to form a reservoir of catalytic diversity maintained as heritable units. Among the many P450s with physiological functions, six CYP families are involved in ecdysteroid metabolism. However, five so-called Halloween genes are not universally represented and do not constitute the unique pathway of ecdysteroid biosynthesis. The diversity of arthropod CYPomes has only partially been uncovered to date and many P450s with physiological functions regulating the synthesis and degradation of endogenous signal molecules (including ecdysteroids) and semiochemicals (including pheromones and defense chemicals) remain to be discovered. Sequence diversity of arthropod P450s is extreme, and P450 sequences lacking the universally conserved Cys ligand to the heme have evolved several times. A better understanding of P450 evolution is needed to discern the relative contributions of stochastic processes and adaptive processes in shaping the size and diversity of CYPomes.

}, keywords = {Detoxification, Ecdysteroid metabolism, Gene clusters, Orthologous groups, P450 Evolution}, issn = {0965-1748}, doi = {10.1016/j.ibmb.2020.103490}, url = {https://linkinghub.elsevier.com/retrieve/pii/S096517482030179X}, author = {Dermauw, Wannes and Van Leeuwen, Thomas and Feyereisen, Ren{\'e}} } @article {360, title = {Functional morphology of a lobopod: case study of an onychophoran leg}, journal = {Royal Society Open Science}, volume = {6}, year = {2019}, month = {16/10/2019}, pages = {191-200}, abstract = {

Segmental, paired locomotory appendages are a characteristic feature of Panarthropoda\—a diversified clade of moulting animals that includes onychophorans (velvet worms), tardigrades (water bears) and arthropods. While arthropods acquired a sclerotized exoskeleton and articulated limbs, onychophorans and tardigrades possess a soft body and unjointed limbs called lobopods, which they inherited from Cambrian lobopodians. To date, the origin and ancestral structure of the lobopods and their transformation into the jointed appendages are all poorly understood. We therefore combined high-resolution computed tomography with high-speed camera recordings to characterize the functional anatomy of a trunk lobopod from the onychophoran Euperipatoides rowelli. Three-dimensional reconstruction of the complete set of muscles and muscle fibres as well as non-muscular structures revealed the spatial relationship and relative volumes of the muscular, excretory, circulatory and nervous systems within the leg. Locomotory movements of individual lobopods of E. rowelli proved far more diverse than previously thought and might be governed by a complex interplay of 15 muscles, including one promotor, one remotor, one levator, one retractor, two depressors, two rotators, one flexor and two constrictors as well as muscles for stabilization and haemolymph control. We discuss the implications of our findings for understanding the evolution of locomotion in panarthropods.

}, keywords = {musculature, myoanatomy, Onychophora, three-dimensional reconstruction, tomography, velvet worm}, issn = {2054-5703}, doi = {10.1098/rsos.191200}, url = {https://royalsocietypublishing.org/doi/10.1098/rsos.191200}, author = {Oliveira, Ivo de Sena and Kumerics, Andreas and Jahn, Henry and M{\"u}ller, Mark and Pfeiffer, Franz and Mayer, Georg} } @article {226, title = {On the specific identity of the Australian Peripatus usually supposed to be P. leuckarti, Saenger}, journal = {Proceedings of the Linnean Society of New South Wales, series 2}, volume = {10}, year = {1895}, month = {09/09/1895}, pages = {172-194}, abstract = {
}, doi = {https://doi.org/10.5962/bhl.part.24340}, url = {https://www.biodiversitylibrary.org/page/6368019}, author = {Fletcher, J. J.} }