The Experts below are selected from a list of 861 Experts worldwide ranked by ideXlab platform
Malcolm Maden - One of the best experts on this subject based on the ideXlab platform.
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a profusion of neural stem cells in the brain of the spiny mouse Acomys cahirinus
Journal of Anatomy, 2021Co-Authors: Malcolm Maden, Nicole Serrano, Monica Bermudez, Aaron Gabriel W. SandovalAbstract:The vast majority of neural stem cell studies have been conducted on the brains of mice and rats, the classical model rodent. Non-model organisms may, however, give us some important insights into how to increase neural stem cell numbers for regenerative purposes and with this in mind we have characterized these cells in the brain of the spiny mouse, Acomys cahirinus. This unique mammal is highly regenerative and damaged tissue does not scar or fibrose. We find that there are more than three times as many stem cells in the SVZ and more than 3 times as many proliferating cells compared to the CD-1 outbred strain of lab mouse. These additional cells create thick stem cell regions in the wall of the SVZ and very obvious columns of cells moving into the rostral migratory stream. In the dentate gyrus, there are more than 10 times as many cells proliferating in the sub-granular layer and twice the number of doublecortin expressing neuroblasts. A preliminary analysis of some stem cell niche genes has identified Sox2, Notch1, Shh, and Noggin as up-regulated in the SVZ of Acomys and Bmp2 as being down-regulated. The highly increased neural stem cell numbers in Acomys may endow this animal with increased regenerative properties in the brain or improved physiological performance important for its survival.
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Spiny mouse (Acomys): an emerging research organism for regenerative medicine with applications beyond the skin
npj Regenerative Medicine, 2021Co-Authors: Janak Gaire, Malcolm Maden, Michael D Sunshine, David D Fuller, Justin A. Varholick, Sabhya Rana, Sylvain Doré, W. Brad Barbazuk, Chelsey S SimmonsAbstract:The spiny mouse (Acomys species ) has emerged as an exciting research organism due to its remarkable ability to undergo scarless regeneration of skin wounds and ear punches. Excitingly, Acomys species demonstrate scar-free healing in a wide-range of tissues beyond the skin. In this perspective article, we discuss published findings from a variety of tissues to highlight how this emerging research organism could shed light on numerous clinically relevant human diseases. We also discuss the challenges of working with this emerging research organism and suggest strategies for future Acomys -inspired research.
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Regeneration in the spiny mouse, Acomys, a new mammalian model.
Current opinion in genetics & development, 2020Co-Authors: Aaron Gabriel W. Sandoval, Malcolm MadenAbstract:We describe the tissues and organs that show exceptional regenerative ability following injury in the spiny mouse, Acomys. The skin and ear regenerate: hair and its associated stem cell niches, sebaceous glands, dermis, adipocytes, cartilage, smooth muscle, and skeletal muscle. Internal tissues such as the heart, kidney, muscle, and spinal cord respond to damage by showing significantly reduced inflammation and improved regeneration responses. The reason for this improved ability may lie in the immune system which shows a blunted inflammatory response to injury compared to that of the typical mammal, but we also show that there are distinct biomechanical properties of Acomys tissues. Examining the regenerative behavior of closely related mammals may provide insights into the evolution of this remarkable property.
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molecular and histologic outcomes following spinal cord injury in spiny mice Acomys cahirinus
The Journal of Comparative Neurology, 2020Co-Authors: Kristi A Streeter, Aaron Gabriel W. Sandoval, Malcolm Maden, Jason O Brant, Michael D Sunshine, David D FullerAbstract:The spiny mouse (Acomys cahirinus) appears to be unique among mammals by showing little scarring or fibrosis after skin or muscle injury, but the Acomys response to spinal cord injury (SCI) is unknown. We tested the hypothesis that Acomys would have molecular and immunohistochemical evidence of reduced spinal inflammation and fibrosis following SCI as compared to C57BL/6 mice (Mus), which similar to all mammals studied to date exhibits spinal scarring following SCI. Initial experiments used two pathway-focused RT-PCR gene arrays ("wound healing" and "neurogenesis") to evaluate tissue samples from the C2-C6 spinal cord 3 days after a C3/C4 hemi-crush injury (C3Hc). Based on the gene array results, specific genes were selected for RT-qPCR evaluation using species-specific primers. The results supported our hypothesis by showing increased inflammation and fibrosis related gene expression (Serpine 1, Plau, and Timp1) in Mus as compared to Acomys (p < .05). RT-qPCR also showed enhanced stem cell and axonal guidance related gene expression (Bmp2, GDNF, and Shh) in Acomys compared to Mus (p < .05). Immunohistochemical evaluation of the spinal lesion at 4 weeks postinjury indicated less collagen IV immunostaining in Acomys (p < .05). Glial fibrillary acidic protein (GFAP) and ionized calcium binding adaptor molecule 1(IBA1) immunostaining indicated morphological differences in the appearance of astrocytes and macrophages/microglia in Acomys. Collectively, the molecular and histologic results support the hypothesis that Acomys has reduced spinal inflammation and fibrosis following SCI. We suggest that Acomys may be a useful comparative model to study adaptive responses to SCI.
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model systems for regeneration the spiny mouse Acomys cahirinus
Development, 2020Co-Authors: Malcolm Maden, Justin A. VarholickAbstract:The spiny mouse, Acomys spp., is a recently described model organism for regeneration studies. For a mammal, it displays surprising powers of regeneration because it does not fibrose (i.e. scar) in response to tissue injury as most other mammals, including humans, do. In this Primer article, we review these regenerative abilities, highlighting the phylogenetic position of the spiny mouse relative to other rodents. We also briefly describe the Acomys tissues that have been used for regeneration studies and the common features of their regeneration compared with the typical mammalian response. Finally, we discuss the contribution that Acomys has made in understanding the general principles of regeneration and elaborate hypotheses as to why this mammal is successful at regenerating.
Jason O Brant - One of the best experts on this subject based on the ideXlab platform.
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molecular and histologic outcomes following spinal cord injury in spiny mice Acomys cahirinus
The Journal of Comparative Neurology, 2020Co-Authors: Kristi A Streeter, Aaron Gabriel W. Sandoval, Malcolm Maden, Jason O Brant, Michael D Sunshine, David D FullerAbstract:The spiny mouse (Acomys cahirinus) appears to be unique among mammals by showing little scarring or fibrosis after skin or muscle injury, but the Acomys response to spinal cord injury (SCI) is unknown. We tested the hypothesis that Acomys would have molecular and immunohistochemical evidence of reduced spinal inflammation and fibrosis following SCI as compared to C57BL/6 mice (Mus), which similar to all mammals studied to date exhibits spinal scarring following SCI. Initial experiments used two pathway-focused RT-PCR gene arrays ("wound healing" and "neurogenesis") to evaluate tissue samples from the C2-C6 spinal cord 3 days after a C3/C4 hemi-crush injury (C3Hc). Based on the gene array results, specific genes were selected for RT-qPCR evaluation using species-specific primers. The results supported our hypothesis by showing increased inflammation and fibrosis related gene expression (Serpine 1, Plau, and Timp1) in Mus as compared to Acomys (p < .05). RT-qPCR also showed enhanced stem cell and axonal guidance related gene expression (Bmp2, GDNF, and Shh) in Acomys compared to Mus (p < .05). Immunohistochemical evaluation of the spinal lesion at 4 weeks postinjury indicated less collagen IV immunostaining in Acomys (p < .05). Glial fibrillary acidic protein (GFAP) and ionized calcium binding adaptor molecule 1(IBA1) immunostaining indicated morphological differences in the appearance of astrocytes and macrophages/microglia in Acomys. Collectively, the molecular and histologic results support the hypothesis that Acomys has reduced spinal inflammation and fibrosis following SCI. We suggest that Acomys may be a useful comparative model to study adaptive responses to SCI.
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molecular and histologic outcomes following spinal cord injury in spiny mice Acomys cahirinus
bioRxiv, 2019Co-Authors: Aaron Gabriel W. Sandoval, Malcolm Maden, Jason O Brant, Kristi A Streeter, Michael D Sunshine, David D FullerAbstract:Abstract The spiny mouse (Acomys cahirinus) appears to be unique among mammals by showing little scarring or fibrosis after skin or muscle injury, but the Acomys response to spinal cord injury (SCI) is unknown. We tested the hypothesis that Acomys would have molecular and immunohistochemical evidence of reduced spinal inflammation and fibrosis following SCI as compared to C57BL/6 mice (Mus), which similar to all mammals studied to date exhibits spinal scarring following SCI. Initial experiments used two pathway-focused RT-PCR gene arrays (“wound healing” and “neurogenesis”) to evaluate tissue samples from the C2-C6 spinal cord 3-days after a C3/C4 hemi-crush injury (C3Hc). Based on the gene array, specific genes were selected for RT-qPCR evaluation using species-specific primers. The results supported our hypothesis by showing increased inflammation and fibrosis related gene expression (Serpine 1, Plau, Timp1) in Mus as compared to Acomys (P Highlights Spiny mice (Acomys cahirinus) and C57BL/6 (Mus) were studied after spinal injury RT-PCR gene arrays suggested different molecular response in Acomys RTq-PCR with species-specific primers showed increased neurogenesis-related signaling Histology indicates reduced scarring and fibrosis in Acomys Acomys may be a useful comparative model to study SCI
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comparative transcriptomic analysis of dermal wound healing reveals de novo skeletal muscle regeneration in Acomys cahirinus
PLOS ONE, 2019Co-Authors: Jason O Brant, Aaron Gabriel W. Sandoval, Malcolm Maden, Lucas J Boatwright, Ruth Davenport, Brad W BarbazukAbstract:The African spiny mouse, Acomys spp., is capable of scar-free dermal wound healing. Here, we have performed a comprehensive analysis of gene expression throughout wound healing following full-thickness excisional dermal wounds in both Acomys cahirinus and Mus musculus. Additionally, we provide an annotated, de novo transcriptome assembly of A. cahirinus skin and skin wounds. Using a novel computational comparative RNA-Seq approach along with pathway and co-expression analyses, we identify enrichment of regeneration associated genes as well as upregulation of genes directly related to muscle development or function. Our RT-qPCR data reveals induction of the myogenic regulatory factors, as well as upregulation of embryonic myosin, starting between days 14 and 18 post-wounding in A. cahirinus. In contrast, the myogenic regulatory factors remain downregulated, embryonic myosin is only modestly upregulated, and no new muscle fibers of the panniculus carnosus are generated in M. musculus wounds. Additionally, we show that Col6a1, a key component of the satellite cell niche, is upregulated in A. cahirinus compared to M. musculus. Our data also demonstrate that the macrophage profile and inflammatory response is different between species, with A. cahirinus expressing significantly higher levels of Il10. We also demonstrate differential expression of the upstream regulators Wnt7a, Wnt2 and Wnt6 during wound healing. Our analyses demonstrate that A. cahirinus is capable of de novo skeletal muscle regeneration of the panniculus carnosus following removal of the extracellular matrix. We believe this study represents the first detailed analysis of de novo skeletal muscle regeneration observed in an adult mammal.
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unique behavior of dermal cells from regenerative mammal the african spiny mouse in response to substrate stiffness
Journal of Biomechanics, 2018Co-Authors: Daniel C Stewart, Malcolm Maden, Nicole P Serrano, Andres Rubiano, Ryosuke Yokosawa, Justin Sandler, Marah Mukhtar, Jason O Brant, Chelsey S SimmonsAbstract:Abstract The African Spiny Mouse (Acomys spp.) is a unique outbred mammal capable of full, scar-free skin regeneration. In vivo, we have observed rapid reepithelialization and deposition of normal dermis in Acomys after wounding. Acomys skin also has a lower modulus and lower elastic energy storage than normal lab mice, Mus musculus. To see if the different in vivo mechanical microenvironments retained an effect on dermal cells and contributed to regenerative behavior, we examined isolated keratinocytes in response to physical wounding and fibroblasts in response to varying substrate stiffness. Classic mechanobiology paradigms suggest stiffer substrates will promote myofibroblast activation, but we do not see this in Acomys dermal fibroblasts (DFs). Though Mus DFs increase organization of α-smooth muscle actin (αSMA)-positive stress fibers as substrate stiffness increases, Acomys DFs assemble very few αSMA-positive stress fibers upon changes in substrate stiffness. Acomys DFs generate lower traction forces than Mus DFs on pliable surfaces, and Acomys DFs produce and modify matrix proteins differently than Mus in 2D and 3D culture systems. In contrast to Acomys DFs “relaxed” behavior, we found that freshly isolated Acomys keratinocytes retain the ability to close wounds faster than Mus in an in vitro scratch assay. Taken together, these preliminary observations suggest that Acomys dermal cells retain unique biophysical properties in vitro that may reflect their altered in vivo mechanical microenvironment and may promote scar-free wound healing.
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cellular events during scar free skin regeneration in the spiny mouse Acomys
Wound Repair and Regeneration, 2016Co-Authors: Jason O Brant, Jung H Yoon, Trey Polvadore, William B Barbazuk, Malcolm MadenAbstract:In contrast to the lab mouse, Mus musculus, several species of spiny mouse, Acomys, can regenerate epidermis, dermis, hairs, sebaceous glands with smooth muscle erector pili muscles and skeletal muscle of the panniculus carnonsus after full thickness skin wounding. Here, we have compared the responses of these scarring and nonscarring organisms concentrating on the immune cells and wound cytokines, cell proliferation, and the collagenous components of the wound bed and scar. The blood of Acomys is very neutropenic but there are greater numbers of mast cells in the Acomys wound than the Mus wound. Most importantly there are no F4/80 macrophages in the Acomys wound and many proinflammatory cytokines are either absent or in very low levels which we suggest may be primarily responsible for the excellent regenerative properties of the skin of this species. There is little difference in cell proliferation in the two species either in the epidermis or mesenchymal tissues but the cell density and matrix composition of the wound is very different. In Mus there are 8 collagens which are up-regulated at least 5-fold in the wound creating a strongly trichrome-positive matrix whereas in Acomys there are very few collagens present and the matrix shows only light trichrome staining. The major component of the Mus matrix is collagen XII which is up-regulated between 10 and 30-fold after wounding. These results suggest that in the Acomys wound the absence of many cytokines resulting in the lack of macrophages is responsible for the failure to up-regulate fibrotic collagens, a situation which permits a regenerative response within the skin rather than the generation of a scar.
Aaron Gabriel W. Sandoval - One of the best experts on this subject based on the ideXlab platform.
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a profusion of neural stem cells in the brain of the spiny mouse Acomys cahirinus
Journal of Anatomy, 2021Co-Authors: Malcolm Maden, Nicole Serrano, Monica Bermudez, Aaron Gabriel W. SandovalAbstract:The vast majority of neural stem cell studies have been conducted on the brains of mice and rats, the classical model rodent. Non-model organisms may, however, give us some important insights into how to increase neural stem cell numbers for regenerative purposes and with this in mind we have characterized these cells in the brain of the spiny mouse, Acomys cahirinus. This unique mammal is highly regenerative and damaged tissue does not scar or fibrose. We find that there are more than three times as many stem cells in the SVZ and more than 3 times as many proliferating cells compared to the CD-1 outbred strain of lab mouse. These additional cells create thick stem cell regions in the wall of the SVZ and very obvious columns of cells moving into the rostral migratory stream. In the dentate gyrus, there are more than 10 times as many cells proliferating in the sub-granular layer and twice the number of doublecortin expressing neuroblasts. A preliminary analysis of some stem cell niche genes has identified Sox2, Notch1, Shh, and Noggin as up-regulated in the SVZ of Acomys and Bmp2 as being down-regulated. The highly increased neural stem cell numbers in Acomys may endow this animal with increased regenerative properties in the brain or improved physiological performance important for its survival.
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Regeneration in the spiny mouse, Acomys, a new mammalian model.
Current opinion in genetics & development, 2020Co-Authors: Aaron Gabriel W. Sandoval, Malcolm MadenAbstract:We describe the tissues and organs that show exceptional regenerative ability following injury in the spiny mouse, Acomys. The skin and ear regenerate: hair and its associated stem cell niches, sebaceous glands, dermis, adipocytes, cartilage, smooth muscle, and skeletal muscle. Internal tissues such as the heart, kidney, muscle, and spinal cord respond to damage by showing significantly reduced inflammation and improved regeneration responses. The reason for this improved ability may lie in the immune system which shows a blunted inflammatory response to injury compared to that of the typical mammal, but we also show that there are distinct biomechanical properties of Acomys tissues. Examining the regenerative behavior of closely related mammals may provide insights into the evolution of this remarkable property.
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molecular and histologic outcomes following spinal cord injury in spiny mice Acomys cahirinus
The Journal of Comparative Neurology, 2020Co-Authors: Kristi A Streeter, Aaron Gabriel W. Sandoval, Malcolm Maden, Jason O Brant, Michael D Sunshine, David D FullerAbstract:The spiny mouse (Acomys cahirinus) appears to be unique among mammals by showing little scarring or fibrosis after skin or muscle injury, but the Acomys response to spinal cord injury (SCI) is unknown. We tested the hypothesis that Acomys would have molecular and immunohistochemical evidence of reduced spinal inflammation and fibrosis following SCI as compared to C57BL/6 mice (Mus), which similar to all mammals studied to date exhibits spinal scarring following SCI. Initial experiments used two pathway-focused RT-PCR gene arrays ("wound healing" and "neurogenesis") to evaluate tissue samples from the C2-C6 spinal cord 3 days after a C3/C4 hemi-crush injury (C3Hc). Based on the gene array results, specific genes were selected for RT-qPCR evaluation using species-specific primers. The results supported our hypothesis by showing increased inflammation and fibrosis related gene expression (Serpine 1, Plau, and Timp1) in Mus as compared to Acomys (p < .05). RT-qPCR also showed enhanced stem cell and axonal guidance related gene expression (Bmp2, GDNF, and Shh) in Acomys compared to Mus (p < .05). Immunohistochemical evaluation of the spinal lesion at 4 weeks postinjury indicated less collagen IV immunostaining in Acomys (p < .05). Glial fibrillary acidic protein (GFAP) and ionized calcium binding adaptor molecule 1(IBA1) immunostaining indicated morphological differences in the appearance of astrocytes and macrophages/microglia in Acomys. Collectively, the molecular and histologic results support the hypothesis that Acomys has reduced spinal inflammation and fibrosis following SCI. We suggest that Acomys may be a useful comparative model to study adaptive responses to SCI.
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molecular and histologic outcomes following spinal cord injury in spiny mice Acomys cahirinus
bioRxiv, 2019Co-Authors: Aaron Gabriel W. Sandoval, Malcolm Maden, Jason O Brant, Kristi A Streeter, Michael D Sunshine, David D FullerAbstract:Abstract The spiny mouse (Acomys cahirinus) appears to be unique among mammals by showing little scarring or fibrosis after skin or muscle injury, but the Acomys response to spinal cord injury (SCI) is unknown. We tested the hypothesis that Acomys would have molecular and immunohistochemical evidence of reduced spinal inflammation and fibrosis following SCI as compared to C57BL/6 mice (Mus), which similar to all mammals studied to date exhibits spinal scarring following SCI. Initial experiments used two pathway-focused RT-PCR gene arrays (“wound healing” and “neurogenesis”) to evaluate tissue samples from the C2-C6 spinal cord 3-days after a C3/C4 hemi-crush injury (C3Hc). Based on the gene array, specific genes were selected for RT-qPCR evaluation using species-specific primers. The results supported our hypothesis by showing increased inflammation and fibrosis related gene expression (Serpine 1, Plau, Timp1) in Mus as compared to Acomys (P Highlights Spiny mice (Acomys cahirinus) and C57BL/6 (Mus) were studied after spinal injury RT-PCR gene arrays suggested different molecular response in Acomys RTq-PCR with species-specific primers showed increased neurogenesis-related signaling Histology indicates reduced scarring and fibrosis in Acomys Acomys may be a useful comparative model to study SCI
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comparative transcriptomic analysis of dermal wound healing reveals de novo skeletal muscle regeneration in Acomys cahirinus
PLOS ONE, 2019Co-Authors: Jason O Brant, Aaron Gabriel W. Sandoval, Malcolm Maden, Lucas J Boatwright, Ruth Davenport, Brad W BarbazukAbstract:The African spiny mouse, Acomys spp., is capable of scar-free dermal wound healing. Here, we have performed a comprehensive analysis of gene expression throughout wound healing following full-thickness excisional dermal wounds in both Acomys cahirinus and Mus musculus. Additionally, we provide an annotated, de novo transcriptome assembly of A. cahirinus skin and skin wounds. Using a novel computational comparative RNA-Seq approach along with pathway and co-expression analyses, we identify enrichment of regeneration associated genes as well as upregulation of genes directly related to muscle development or function. Our RT-qPCR data reveals induction of the myogenic regulatory factors, as well as upregulation of embryonic myosin, starting between days 14 and 18 post-wounding in A. cahirinus. In contrast, the myogenic regulatory factors remain downregulated, embryonic myosin is only modestly upregulated, and no new muscle fibers of the panniculus carnosus are generated in M. musculus wounds. Additionally, we show that Col6a1, a key component of the satellite cell niche, is upregulated in A. cahirinus compared to M. musculus. Our data also demonstrate that the macrophage profile and inflammatory response is different between species, with A. cahirinus expressing significantly higher levels of Il10. We also demonstrate differential expression of the upstream regulators Wnt7a, Wnt2 and Wnt6 during wound healing. Our analyses demonstrate that A. cahirinus is capable of de novo skeletal muscle regeneration of the panniculus carnosus following removal of the extracellular matrix. We believe this study represents the first detailed analysis of de novo skeletal muscle regeneration observed in an adult mammal.
David W Walker - One of the best experts on this subject based on the ideXlab platform.
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de novo transcriptome assembly for the spiny mouse Acomys cahirinus
Scientific Reports, 2017Co-Authors: Jared Mamrot, Roxane Legaie, Stacey J Ellery, Trevor Wilson, Torsten Seemann, David R Powell, David K Gardner, David W WalkerAbstract:Spiny mice of the genus Acomys display several unique physiological traits, including menstruation and scar-free wound healing; characteristics that are exceedingly rare in mammals, and of considerable interest to the scientific community. These unique attributes, and the potential for spiny mice to accurately model human diseases, are driving increased use of this genus in biomedical research, however little genetic information is accessible for this species. This project aimed to generate a draft transcriptome for the Common spiny mouse (Acomys cahirinus). Illumina sequencing of RNA from 15 organ types (male and female) produced 451 million, 150 bp paired-end reads (92.4Gbp). An extensive survey of de novo transcriptome assembly approaches using Trinity, SOAPdenovo-Trans, and Oases at multiple kmer lengths was conducted, producing 50 single-kmer assemblies from this dataset. Non-redundant transcripts from all assemblies were merged into a meta-assembly using the EvidentialGene tr2aacds pipeline, producing the largest gene catalogue to date for Acomys cahirinus. This study provides the first detailed characterization of the spiny mouse transcriptome. It validates use of the EvidentialGene tr2aacds pipeline in mammals to augment conventional de novo assembly approaches, and provides a valuable scientific resource for further investigation into the unique physiological characteristics inherent in the genus Acomys.
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de novo transcriptome assembly for the spiny mouse Acomys cahirinus
bioRxiv, 2016Co-Authors: Jared Mamrot, Roxane Legaie, Stacey J Ellery, Trevor Wilson, David K Gardner, David W Walker, Peter Templesmith, Anthony T Papenfuss, Hayley DickinsonAbstract:Background: Spiny mice of the genus Acomys are small desert-dwelling rodents that display physiological characteristics not typically found in rodents. Recent investigations have reported a menstrual cycle and scar free-wound healing in this species; characteristics that are exceedingly rare in mammals, and of considerable interest to the scientific community. These unique physiological traits, and the potential for spiny mice to accurately model human diseases, are driving increased use of this genus in biomedical research. However, little genetic information is currently available for Acomys, limiting the application of some modern investigative techniques. This project aimed to generate a reference transcriptome assembly for the common spiny mouse (Acomys cahirinus). Results: Illumina RNA sequencing of male and female spiny mice produced 451 million, 150bp paired-end reads from 15 organ types. An extensive survey of de novo transcriptome assembly approaches of high-quality reads using Trinity, SOAPdenovo-Trans, and Velvet/Oases at multiple kmer lengths was conducted with 49 single-kmer assemblies generated from this dataset, with and without in silico normalization and probabilistic error correction. Merging transcripts from 49 individual single-kmer assemblies into a single meta-assembly of non-redundant transcripts using the EvidentialGene 'tr2aacds' pipeline produced the highest quality transcriptome assembly, comprised of 880,080 contigs, of which 189,925 transcripts were annotated using the SwissProt/Uniprot database. Conclusions: This study provides the first detailed characterization of the spiny mouse transcriptome. It validates the application of the EvidentialGene 'tr2aacds' pipeline to generate a high-quality reference transcriptome assembly in a mammalian species, and provides a valuable scientific resource for further investigation into the unique physiological characteristics inherent in the genus Acomys.
Tamar Dayan - One of the best experts on this subject based on the ideXlab platform.
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effect of artificial night lighting on temporally partitioned spiny mice
Journal of Mammalogy, 2011Co-Authors: Shay Rotics, Tamar Dayan, Noga KronfeldschorAbstract:Abstract We studied the effect of ecological light pollution on a rocky desert community, focusing on 2 spiny mouse congeners, nocturnal Acomys cahirinus (common spiny mouse) and diurnal Acomys russatus (golden spiny mouse). We hypothesized that in response to artificial illumination A. cahirinus will decrease its activity and A. russatus will increase its activity, and thus temporal overlap and interspecific competition could increase. Our study took place in 4 field enclosures: the 1st and 3rd months were controls with natural light, and in the 2nd month artificial illumination, simulating low levels of light pollution, was set for the first 3 h of the night. We implanted temperature-sensitive radiotransmitters to monitor mouse activity, and individual identification tags with automonitored foraging patches were used to track foraging behavior. A. cahirinus decreased activity and foraging with artificial lighting, restricting movement particularly in less-sheltered microhabitats, probably because of inc...
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population biology and spatial relationships of coexisting spiny mice Acomys in israel
Journal of Mammalogy, 2000Co-Authors: Eyal Shargal, Noga Kronfeldschor, Tamar DayanAbstract:Nocturnally active Acomys cahirinus and diurnally active A. russatus cooccur in hot rocky deserts, and their temporal partitioning results from competition. We studied their population biology at Ein Gedi near the Dead Sea to determine their spatial relationships and gain insight into their ecological overlap. Individuals of both species were trapped repeatedly for almost 2 years. Mean body mass did not change seasonally, and A. russatus was significantly heavier than A. cahirinus. Density of A. russatus was significantly greater than that of A. cahirinus. Acomys russatus had a shorter reproductive peak that overlapped the longer reproductive season of A. cahirinus. Acomys russatus showed a significant preference for boulder habitat versus open habitat at all seasons, whereas A. cahirinus showed a preference for boulder habitat only half of the time. Sexes of both species overlapped in home range.
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foraging behavior and microhabitat use by spiny mice Acomys cahirinus and a russatus in the presence of blanford s fox vulpes cana odor
Journal of Chemical Ecology, 2000Co-Authors: Menna E Jones, Tamar DayanAbstract:We investigated the responses of common and golden spiny mice (Acomys cahirinus and A. russatus, respectively) to the fecal odor of Blanford's fox (Vulpes cana), a predator of Acomys, which overlaps in habitat use with the mice. Neither species of mouse showed a significant response to the presence of fox odor compared with the presence of the fecal odor of a local herbivore (Nubian ibex, Capra ibex nubia). One explanation is that the impact of predation from V. cana may be sufficiently low that the cost of avoidance, in terms of missed feeding opportunities, conveys little selective advantage. Alternatively, fecal odor may not provide a focused cue of immediate danger for spiny mice. The diurnal A. russatus showed a stronger (near significant) response than the nocturnal A. cahirinus to fecal odor of this nocturnal predator. This may be a legacy of the underlying nocturnal activity rhythm of A. russatus or may indicate a generally more cautious response to predator odors, as A. russatus has a much stronger preference for sheltered microhabitats than A. cahirinus.
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the dietary basis for temporal partitioning food habits of coexisting Acomys species
Oecologia, 1999Co-Authors: Noga Kronfeldschor, Tamar DayanAbstract:Two rodent species of the genus Acomys coexist on rocky terrain in the southern deserts of Israel. The common spiny mouse (A. cahirinus) is nocturnally active whereas the golden spiny mouse (A. russatus) is diurnally active. An early removal study suggested that competition accounts for this pattern of temporal partitioning: the golden spiny mouse is forced into diurnal activity by its congener. Theoretically, temporal segregation should facilitate coexistence if the shared limiting resources differ at different times (primarily among predators whose prey populations have activity rhythms), or if they are renewed within the period of the temporal segregation. We studied food preferences of the two Acomys species in a controlled cafeteria experiment in order to assess resource overlap and the potential for competition for food between the two species. We found no significant difference in food preferences between species. The dietary items preferred by both were arthropods. We also carried out a seasonal study of the percentage and identity of arthropods taken in the field by individuals of the two species. Individuals of both species took on annual average a high percentage of arthropods in their diets. Seasonal diet shifts reflect seasonal abundance of arthropods at Ein Gedi during day and night. Diurnal activity may also reduce interspecific interference competition between A. russatus and A. cahirinus. However, the strong interspecific dietary overlap in food preference, the heavy reliance on arthropods in spiny mouse diets, and the seasonal and circadian differences in arthropod consumption suggest that prey partitioning may be a viable mechanism of coexistence in this system.
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telemetric field studies of body temperature and activity rhythms of Acomys russatus and a cahirinus in the judean desert of israel
Oecologia, 1999Co-Authors: Ralf Elvert, Tamar Dayan, Abraham Haim, Nava Zisapel, Noga Kronfeld, Gerhard HeldmaierAbstract:Two species of the genus Acomys coexist in arid zones of southern Israel. Acomys russatus is distributed in extremely arid areas, while A. cahirinus is common in both Mediterranean and arid regions. Individuals of both species from a rodent community in the Ein Gedi Nature Reserve were implanted with temperature-sensitive transmitters. Body temperature (Tb) rhythms were recorded in free-ranging mice at four different seasons of the year. A. cahirinus (30–45 g) showed a nocturnal rhythm of Tb throughout the year. In the activity phase during the night Tb increased to 38.2°C. During the day Tb decreased to 34°C. This species displayed this pattern in summer also when ambient temperatures rose above Tb. The Tb of A. russatus (45–65 g) varied between 34.8 and 41°C during the hot season, showing a bimodal temperature rhythm with maximal values in the morning and in the evening. Measurements of activity in this species showed inactivity during the hottest period of a summer day. In winter A. russatus showed no clearly detectable diurnal or ultradian rhythm in Tb, which remained constant between narrow limits of 35.2 and 36.8°C.
