1,342 research outputs found
The milliped family Tingupidae (Chordeumatida) on Kodiak Island, Alaska, USA, a geographically remote record of indigenous Diplopoda
With documentation of an unidentifiable adult female and juvenile Tingupidae (Chordeumatida), Kodiak Island, Alaska, becomes the westernmost indigenous diplopod locality in North America including continental islands. The northernmost and most proximate locality, Yakutat, lies ca. 935 mi (1,496 km) to the eastnortheast, while Haines, the type locality of Tingupa tlingitorum Shear and Shelley, some 1,196 mi (1,914 km) in this direction, is the most proximate familial site. Kodiak is also one of the most remote indigenous milliped localities in the Pacific, the most proximate ones to the west and south, Kamchatka, Russia, and the Hawaiian Islands, United States, being over 3,300 mi (5, 280 km) distant. Tingupidae is recorded for the first time from Canada excluding the Queen Charlotte Islands, and geographically remote, ostensibly indigenous records from the North Pacific Ocean and environs are tabulated
Quantitative Trait Loci (QTLs) mapping for growth traits in the mouse: A review
The attainment of a specific mature body size is one of the most fundamental differences among species of mammals. Moreover, body size seems to be the central factor underlying differences in traits such as growth rate, energy metabolism and body composition. An important proportion of this variability is of genetic origin. The goal of the genetic analysis of animal growth is to understand its "genetic architecture", that is the number and position of loci affecting the trait, the magnitude of their effects, allele frequencies and types of gene action. In this review, the different strategies developed to identify and characterize genes involved in the regulation of growth in the mouse are described, with emphasis on the methods developed to map loci contributing to the regulation of quantitative traits (QTLs)
Genome-wide isolation of growth and obesity QTL using mouse speed congenic strains
BACKGROUND: High growth (hg) modifier and background independent quantitative trait loci (QTL) affecting growth, adiposity and carcass composition were previously identified on mouse chromosomes (MMU) 1, 2, 5, 8, 9, 11 and 17. To confirm and further characterize each QTL, two panels of speed congenic strains were developed by introgressing CAST/EiJ (CAST) QTL alleles onto either mutant C57Bl/6J-hg/hg (HG) or wild type C57Bl/6J (B6) genetic backgrounds. RESULTS: The first speed congenic panel was developed by introgressing four overlapping donor regions spanning MMU2 in its entirety onto both HG and B6 backgrounds, for a total of eight strains. Phenotypic characterization of the MMU2 panel confirmed the segregation of multiple growth and obesity QTL and strongly suggested that a subset of these loci modify the effects of the hg deletion. The second panel consisted of individual donor regions on an HG background for each QTL on MMU1, 5, 8, 9, 11 and 17. Of the six developed strains, five were successfully characterized and displayed significant differences in growth and/or obesity as compared to controls. All five displayed phenotypes similar to those originally attributed to each QTL, however, novel phenotypes were unmasked in several of the strains including sex-specific effects. CONCLUSION: The speed congenic strains developed herein constitute an invaluable genomic resource and provide the foundation to identify the specific nature of genetic variation influencing growth and obesity
The evolution of the natural killer complex; a comparison between mammals using new high-quality genome assemblies and targeted annotation.
Natural killer (NK) cells are a diverse population of lymphocytes with a range of biological roles including essential immune functions. NK cell diversity is in part created by the differential expression of cell surface receptors which modulate activation and function, including multiple subfamilies of C-type lectin receptors encoded within the NK complex (NKC). Little is known about the gene content of the NKC beyond rodent and primate lineages, other than it appears to be extremely variable between mammalian groups. We compared the NKC structure between mammalian species using new high-quality draft genome assemblies for cattle and goat; re-annotated sheep, pig, and horse genome assemblies; and the published human, rat, and mouse lemur NKC. The major NKC genes are largely in the equivalent positions in all eight species, with significant independent expansions and deletions between species, allowing us to propose a model for NKC evolution during mammalian radiation. The ruminant species, cattle and goats, have independently evolved a second KLRC locus flanked by KLRA and KLRJ, and a novel KLRH-like gene has acquired an activating tail. This novel gene has duplicated several times within cattle, while other activating receptor genes have been selectively disrupted. Targeted genome enrichment in cattle identified varying levels of allelic polymorphism between the NKC genes concentrated in the predicted extracellular ligand-binding domains. This novel recombination and allelic polymorphism is consistent with NKC evolution under balancing selection, suggesting that this diversity influences individual immune responses and may impact on differential outcomes of pathogen infection and vaccination
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Deducing signaling pathways from parallel actions of arsenite and antimonite in human epidermal keratinocytes.
Inorganic arsenic oxides have been identified as carcinogens in several human tissues, including epidermis. Due to the chemical similarity between trivalent inorganic arsenic (arsenite) and antimony (antimonite), we hypothesized that common intracellular targets lead to similarities in cellular responses. Indeed, transcriptional and proteomic profiling revealed remarkable similarities in differentially expressed genes and proteins resulting from exposure of cultured human epidermal keratinocytes to arsenite and antimonite in contrast to comparisons of arsenite with other metal compounds. These data were analyzed to predict upstream regulators and affected signaling pathways following arsenite and antimonite treatments. A majority of the top findings in each category were identical after treatment with either compound. Inspection of the predicted upstream regulators led to previously unsuspected roles for oncostatin M, corticosteroids and ephrins in mediating cellular response. The influence of these predicted mediators was then experimentally verified. Together with predictions of transcription factor effects more generally, the analysis has led to model signaling networks largely accounting for arsenite and antimonite action. The striking parallels between responses to arsenite and antimonite indicate the skin carcinogenic risk of exposure to antimonite merits close scrutiny
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Study of Different Aging Conditions for Analysis of Microstructure and Mechanical Properties of F357 Alloy Fabricated in LPBF Printer
Aluminum F357 is a widely used material for casting in aerospace and additive manufacturing
industry. Heat treatments are commonly applied to some aluminum alloys to modify its
properties. With a further study on the aging and performance of the F357 with 3D printing
technology, several industries benefit of this, military, automotive and aerospace are some
examples, because the numerous components casted in service. This work presents mechanical
properties of F357 specimens fabricated with EOS technology and subjected to heat treatments.
Heat treatments conditions were applied to tensile specimens and tested. Furthermore, the
specimens were subjected to artificial thermal aging for 100 h and 1000 h at two different
temperatures (285 ºF and 350 ºF), and their mechanical properties were also determined. Finally,
remarks on the comparison between the heat treatments and the effect of thermal aging on the
microstructures and mechanical properties of the specimens will be presented.Mechanical Engineerin
NiO/CaAl2O4 as active oxygen carrier for low temperature chemical looping applications
The implementation of CO2 capture systems in conventional processes has been proposed by the IPCC as an effective way to reduce anthropogenic CO2 emissions. However, these capture systems may represent an important decrease in the global efficiency for conventional processes. Chemical Looping has already been demonstrated as a promising technology for more efficient CO2 capture. Novel reactor concepts have been proposed in the literature, in which the reactions take place at lower temperatures with increased overall energy efficiency. However, few investigations have been carried out regarding the behaviour of oxygen carriers at relatively low operating temperatures. In this work, an active Ni-based oxygen carrier supported on CaAl2O4 inert material has been tested and characterized. The oxygen carrier has shown a promising behaviour for low temperature applications. However, it has been demonstrated that the oxygen carrier has to be pre-treated because of an interesting activation process which takes place only at high reduction temperatures. Oxygen carrier activation is caused by a reorganization of superficial nickel. Fresh oxygen carrier is covered by a layer of nickel with a strong interaction with the support. However, once the sample is reduced at high temperatures Ni is reorganized into small grains with reduced interaction with the support. This results in an enhancement in the reactivity and a higher oxygen transport capacity. After about 200 redox cycles, a small decrease in the solid conversion is observed due to agglomeration of the NiO grains. Nevertheless, the redox kinetics is still sufficiently fast for low temperature applications, provided that the oxygen carrier is pre-activated. The kinetics rates for the gas–solid reactions and gas-phase catalytic reactions have been determined, which can be used to predict the performance of the activated NiO/CaAl2O4 oxygen carrier for low temperature chemical looping applications
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