In contrast to the lab mouse, Mus musculus, several species of spiny mouse, Acomys, can regenerat... more 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 non-scarring 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 pro-inflammatory 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. This article is protected by copyright. All rights reserved.
ABSTRACT Molecular markers are valuable tools for basic and applied research. Any detectable type... more ABSTRACT Molecular markers are valuable tools for basic and applied research. Any detectable type of polymorphism in proteins or DNA can potentially be used as a molecular marker. After genotyping multiple members of a population of genetically related individuals with multiple markers, it is possible to generate a genetic map. Molecular markers and genetic maps can be used to associate specific chromosomal intervals (and depending on marker density, even specific genes) with phenotypes and traits. The genetic mapping of mutants or qualitative variation facilitates marker assisted selection (MAS) and is the first step in cloning the affected genes via chromosome walking. Sequence-based genetic markers can be used to cross-link genetic, physical, and cytological maps of maize and reveal patterns of microsynteny among homeologous and orthologous chromosomal segments within the genome and syntenic relationships with other species. Genetic maps can enhance our understanding of the organization and evolution of the maize genome. They also reveal genome-wide patterns of chromosome structure, gene distribution, and meiotic recombination.
Spiny mice (Acomys cahirinus) are an emerging animal model in studies measuring tissue regenerati... more Spiny mice (Acomys cahirinus) are an emerging animal model in studies measuring tissue regeneration, but decades of research on social dominance in other animals indicates the relationships animals form in their home-cage may affect phenotypic plasticity in tissue regeneration and glucocorticoids. Studies in baboons and mice, for example, indicate that subordinate ranked animals heal wounds slower than their dominant group-mates, and have increased levels of basal glucocorticoids. Recent studies in tissue regeneration with salamanders and zebrafish indicate that increased glucocorticoids can delay tissue regeneration, but whether this effect extends to Acomys is unknown, especially regarding their social dominance relationships. Here we report that most adult Acomys had a social dominance status, but many groups had unclear social stability, with more frequent huddling than fighting during their active cycle. We also found no sex differences in social dominance behavior, and that Ac...
Approximately 80% of the maize genome comprises highly repetitive sequences interspersed with sin... more Approximately 80% of the maize genome comprises highly repetitive sequences interspersed with single-copy, gene-rich sequences, and standard genome sequencing strategies are not readily adaptable to this type of genome. Methodologies that enrich for genic sequences might more rapidly generate useful results from complex genomes. Equivalent numbers of clones from maize selected by techniques called methylation filtering and High C 0 t selection were sequenced to generate â¼200,000 reads (approximately 132 megabases), which were assembled into contigs. Combination of the two techniques resulted in a sixfold reduction in the effective genome size and a fourfold increase in the gene identification rate in comparison to a nonenriched library.
In contrast to the lab mouse, Mus musculus, several species of spiny mouse, Acomys, can regenerat... more 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 non-scarring 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 pro-inflammatory 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. This article is protected by copyright. All rights reserved.
ABSTRACT Molecular markers are valuable tools for basic and applied research. Any detectable type... more ABSTRACT Molecular markers are valuable tools for basic and applied research. Any detectable type of polymorphism in proteins or DNA can potentially be used as a molecular marker. After genotyping multiple members of a population of genetically related individuals with multiple markers, it is possible to generate a genetic map. Molecular markers and genetic maps can be used to associate specific chromosomal intervals (and depending on marker density, even specific genes) with phenotypes and traits. The genetic mapping of mutants or qualitative variation facilitates marker assisted selection (MAS) and is the first step in cloning the affected genes via chromosome walking. Sequence-based genetic markers can be used to cross-link genetic, physical, and cytological maps of maize and reveal patterns of microsynteny among homeologous and orthologous chromosomal segments within the genome and syntenic relationships with other species. Genetic maps can enhance our understanding of the organization and evolution of the maize genome. They also reveal genome-wide patterns of chromosome structure, gene distribution, and meiotic recombination.
Spiny mice (Acomys cahirinus) are an emerging animal model in studies measuring tissue regenerati... more Spiny mice (Acomys cahirinus) are an emerging animal model in studies measuring tissue regeneration, but decades of research on social dominance in other animals indicates the relationships animals form in their home-cage may affect phenotypic plasticity in tissue regeneration and glucocorticoids. Studies in baboons and mice, for example, indicate that subordinate ranked animals heal wounds slower than their dominant group-mates, and have increased levels of basal glucocorticoids. Recent studies in tissue regeneration with salamanders and zebrafish indicate that increased glucocorticoids can delay tissue regeneration, but whether this effect extends to Acomys is unknown, especially regarding their social dominance relationships. Here we report that most adult Acomys had a social dominance status, but many groups had unclear social stability, with more frequent huddling than fighting during their active cycle. We also found no sex differences in social dominance behavior, and that Ac...
Approximately 80% of the maize genome comprises highly repetitive sequences interspersed with sin... more Approximately 80% of the maize genome comprises highly repetitive sequences interspersed with single-copy, gene-rich sequences, and standard genome sequencing strategies are not readily adaptable to this type of genome. Methodologies that enrich for genic sequences might more rapidly generate useful results from complex genomes. Equivalent numbers of clones from maize selected by techniques called methylation filtering and High C 0 t selection were sequenced to generate â¼200,000 reads (approximately 132 megabases), which were assembled into contigs. Combination of the two techniques resulted in a sixfold reduction in the effective genome size and a fourfold increase in the gene identification rate in comparison to a nonenriched library.
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Papers by W. Brad Barbazuk