52 results on '"Wang, Guiming"'
Search Results
2. Habitat connectivity drives panda recovery.
- Author
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Wang M, Wang G, Huang G, Kouba A, Swaisgood RR, Zhou W, Hu Y, Nie Y, and Wei F
- Subjects
- Animals, China, Population Density, Endangered Species, Population Dynamics, Ursidae physiology, Ursidae genetics, Ecosystem, Conservation of Natural Resources methods, Gene Flow
- Abstract
Globally, the majority of habitat loss is irreversible, and most species will never recover their former ranges. We have learned a great deal about what leads to population decline and extinction, but less about recovery. The recently downlisted giant panda provides a unique opportunity to understand the mechanisms of species recovery. In our study, we estimate giant panda suitable habitats, population density, and gene flow across landscapes to fully investigate the direct and indirect ecological mechanisms underlying bold conservation strategies. We found that the Giant Panda National Survey has modestly but systematically underestimated population size. China's effort to mitigate anthropogenic disturbances was associated with increased panda population density through improving habitat quality and reducing habitat fragmentation. Enhanced landscape connectivity reduced inbreeding via gene flow but indirectly increased inbreeding temporarily due to high local panda density. Although the panda's recovery has been geographically uneven, we provide evidence for improving connectivity and gene flow resulting from conservation efforts. If these processes can be sustained and improved, the panda's path to recovery will be less encumbered by loss of genetic diversity, fostering hope that the present rate of recovery will not be stalled. Findings from this study will not only help guide future giant panda conservation management but also provide a model for how a more mechanistic examination of the genetic processes underlying species recovery can foster the development of more effective strategies for endangered species recovery., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 Elsevier Inc. All rights reserved.)
- Published
- 2024
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3. The relationship between expression of Tspan5 mRNA in maternal-fetal interface and tubal pregnancy.
- Author
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Wei S, Gao T, Wu Y, Wang G, Chen Y, Tao X, Liang Y, Zhou Z, Sun L, Liu M, Li H, and Bao Y
- Subjects
- Female, Humans, Pregnancy, Placenta metabolism, RNA, Messenger, Pregnancy, Tubal genetics, Tetraspanins genetics, Tetraspanins metabolism
- Abstract
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
- Published
- 2024
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4. Mesenchymal stem cell-derived extracellular vesicles protect against abdominal aortic aneurysm formation by inhibiting NET-induced ferroptosis.
- Author
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Chen L, Liu Y, Wang Z, Zhang L, Xu Y, Li Y, Zhang L, Wang G, Yang S, and Xue G
- Subjects
- Mice, Animals, Phosphatidylinositol 3-Kinases metabolism, Proto-Oncogene Proteins c-akt metabolism, Myocytes, Smooth Muscle metabolism, Disease Models, Animal, Extracellular Traps metabolism, Ferroptosis, Aortic Aneurysm, Abdominal chemically induced, Mesenchymal Stem Cells metabolism, Extracellular Vesicles metabolism
- Abstract
Neutrophil extracellular traps (NETs) play an important role in abdominal aortic aneurysm (AAA) formation; however, the underlying molecular mechanisms remain unclear. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) may exert therapeutic effects on AAA through their immunomodulatory and regenerative abilities. This study aimed to examine the role and mechanism of MSC-EVs in regulating the development of NET-mediated AAA. Excessive release of NETs was observed in patients with AAA, and the levels of NET components were associated with the clinical outcomes of the patients. Datasets from the Gene Expression Omnibus database were analyzed and revealed that the PI3K/AKT pathway and ferroptosis were strongly associated with NETosis during AAA formation. Further experiments verified that NETs promoted AAA formation by inducing ferroptosis in smooth muscle cells (SMCs) by inhibiting the PI3K/AKT pathway. The PI3K agonist 740 Y-P, the ferroptosis inhibitor ferrostatin-1, and Padi4 deficiency significantly prevented AAA formation. MSC-EVs attenuated AAA formation by reducing NET release in an angiotensin II-induced AAA mouse model. In vitro experiments revealed that MSC-EVs reduced the release of NETs by shifting NETosis to apoptosis. Our study indicates an important role for NET-induced SMC ferroptosis in AAA formation and provides several potential targets for AAA treatment., (© 2023. The Author(s).)
- Published
- 2023
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5. Laplace approximation for conditional autoregressive models for spatial data of diseases.
- Author
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Wang G
- Abstract
Conditional autoregressive (CAR) distributions are used to account for spatial autocorrelation in small areal or lattice data to assess the spatial risks of diseases. The intrinsic CAR (ICAR) distribution has been primarily used as the priori distribution of spatially autocorrelated random variables in the framework of Bayesian statistics. The posterior distributions of spatial variates and unknown parameters of Bayesian ICAR models are estimated with the Markov chain Monte Carlo (MCMC) methods or integrated nested Laplace approximation (INLA), which may suffer from failures in numeric convergence. This study used the Laplace approximation, a fast computational method available in software Template Model Builder (TMB), for the maximum likelihood estimation (MLEs) of the ICAR model parameters. This study used the TMB to integrate out the latent spatial variates for the fast computations of marginal likelihood functions. This study compared the runtime and performance among the TMB, MCMC, and INLA implementations with three case studies of human diseases in the United Kingdom and the United States. The MLEs of the ICAR model with TMB were similar to those by the MCMC and INLA methods. The TMB implementation was faster than the MCMC (up to 100-200 times) and INLA (nine times) models. • This study built conditional autoregressive models in template model builder • TMB implementation was 100-200 times faster than the MCMC method • TMB implementation was also faster than Bayesian approximation with R INLA., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 The Author(s). Published by Elsevier B.V.)
- Published
- 2022
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6. Seasonal climatic niche and migration movements of Double-crested Cormorants.
- Author
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King DT, Wang G, and Cunningham FL
- Abstract
Avian migrants are challenged by seasonal adverse climatic conditions and energetic costs of long-distance flying. Migratory birds may track or switch seasonal climatic niche between the breeding and non-breeding grounds. Satellite tracking enables avian ecologists to investigate seasonal climatic niche and circannual movement patterns of migratory birds. The Double-crested Cormorant ( Nannopterum auritum , hereafter cormorant) wintering in the Gulf of Mexico (GOM) migrates to the Northern Great Plains and Great Lakes and is of economic importance because of its impacts on aquaculture. We tested the climatic niche switching hypothesis that cormorants would switch climatic niche between summer and winter because of substantial differences in climate between the non-breeding grounds in the subtropical region and breeding grounds in the northern temperate region. The ordination analysis of climatic niche overlap indicated that cormorants had separate seasonal climatic niche consisting of seasonal mean monthly minimum and maximum temperature, seasonal mean monthly precipitation, and seasonal mean wind speed. Despite non-overlapping summer and winter climatic niches, cormorants appeared to be subjected to similar wind speed between winter and summer habitats and were consistent with similar hourly flying speed between winter and summer. Therefore, substantial differences in temperature and precipitation may lead to the climatic niche switching of fish-eating cormorants, a dietary specialist, between the breeding and non-breeding grounds., Competing Interests: The authors have no conflict of interest related to this work., (© 2022 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.)
- Published
- 2022
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7. Reply: Topographic Anatomy of the Zygomatico-Orbital Artery: Implications for Improving the Safety of Temporal Augmentation.
- Author
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Liu S, Wang G, and Wang H
- Subjects
- Arteries surgery, Head, Humans, Zygoma surgery, Orbital Fractures, Zygomatic Fractures
- Published
- 2022
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8. Climate affects the outbreaks of a forest defoliator indirectly through its tree hosts.
- Author
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Haynes KJ, Liebhold AM, Lefcheck JS, Morin RS, and Wang G
- Subjects
- Animals, Climate, Disease Outbreaks, Forests, Climate Change, Trees
- Abstract
Although spatial variation in climate can directly affect the survival and reproduction of forest insects and the tree species compositions of forests, little is known about the indirect effects of climate on outbreaks of forest insects through its effects on forest composition. In this study, we use structural equation modeling to examine the direct and indirect effects of climate, water capacity of the soil, host tree density, and non-host density on the spatial extent of Lymantria dispar outbreaks in the Eastern USA over a period of 44 years (1975-2018). Host species were subdivided into four taxonomic and ecologically distinct groups: red oaks (Lobatae), white oaks (Lepidobalanus), other preferred hosts, and intermediate (less preferred) hosts. We found that mean annual temperature had stronger effects than mean annual precipitation on the spatial extent of outbreaks, and that indirect effects of temperature (via its effects on oak density) on defoliation were stronger than direct effects. The density of non-host trees increased with increasing precipitation and, consistent with the 'associational resistance hypothesis', defoliation decreased with increasing density of non-host trees. This study offers quantitative evidence that geographic variation in climate can indirectly affect outbreaks of a forest insect through its effects on tree species composition., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)
- Published
- 2022
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9. The Effects of Different UVA Photoperiods on the Growth Performance, Immune Responses, Antioxidant Status and Apoptosis-Related Gene Expression of the Pacific White Shrimp ( Penaeus vannamei ).
- Author
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Wang X, Liu B, Gao X, Wang X, Li H, Xu L, Wang G, Zhao K, and Huang B
- Abstract
UVA is the most common type of solar UV radiation in aquatic environments; however, the effects it causes in shrimp farming in recirculating water systems (RAS) is unclear. Thus, the growth performance, immune responses, antioxidant status and apoptosis-related gene expression in Pacific white shrimp, Penaeus vannamei (body weight 9.56 ± 0.10 g), reared with 12L: 12D full spectrum light as background light under five UVA (peak at 400 nm) photoperiods (0L: 24D, 2L: 22D, 4L: 20D, 8L: 16D and 12L: 12D) at a light intensity of 1 W/m
2 were investigated. The results showed that the 2L: 22D and 4L: 20D UVA photoperiods enhanced the growth performance and reduced the feed conversion ratio and the shrimp mortality. Shrimp exposed to UVA (2L: 22D and 4L: 20D) also displayed higher levels of hepatopancreas catalase (CAT), superoxide dismutase (SOD), acid phosphatase (ACP), phenol oxidase (PO) and lysozyme (LZM) compared to the 8L: 16D and 12L: 12D groups. The malondialdehyde (MDA) levels increased in line with the extension of the UVA irradiation time. The mRNA expression of apoptosis-related genes in all the UVA treatments were significantly higher than with the control treatment, except for the 2L: 22D group. The results of the 2L: 22D and 4L: 20D treatments were significantly higher than those of the control group, except for LGBP. In conclusion, 2L: 22D and 4L: 20D UVA photoperiods increased growth performance and decreased FCR, improved the innate immunity and antioxidant response and reduced the mortality rate in adult shrimp.- Published
- 2021
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10. Timing outweighs magnitude of rainfall in shaping population dynamics of a small mammal species in steppe grassland.
- Author
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Li G, Wan X, Yin B, Wei W, Hou X, Zhang X, Batsuren E, Zhao J, Huang S, Xu X, Liu J, Song Y, Ozgul A, Dickman CR, Wang G, Krebs CJ, and Zhang Z
- Subjects
- Animals, Arvicolinae classification, Arvicolinae physiology, Biomass, China, Climate Change, Feeding Behavior, Population Dynamics, Probability, Reproduction, Survival Analysis, Arvicolinae growth & development, Grassland, Rain
- Abstract
Climate change-induced shifts in species phenology differ widely across trophic levels, which may lead to consumer-resource mismatches with cascading population and ecosystem consequences. Here, we examined the effects of different rainfall patterns (i.e., timing and amount) on the phenological asynchrony of population of a generalist herbivore and their food sources in semiarid steppe grassland in Inner Mongolia. We conducted a 10-y (2010 to 2019) rainfall manipulation experiment in 12 0.48-ha field enclosures and found that moderate rainfall increases during the early rather than late growing season advanced the timing of peak reproduction and drove marked increases in population size through increasing the biomass of preferred plant species. By contrast, greatly increased rainfall produced no further increases in vole population growth due to the potential negative effect of the flooding of burrows. The increases in vole population size were more coupled with increased reproduction of overwintered voles and increased body mass of young-of-year than with better survival. Our results provide experimental evidence for the fitness consequences of phenological mismatches at the population level and highlight the importance of rainfall timing on the population dynamics of small herbivores in the steppe grassland environment., Competing Interests: The authors declare no competing interest., (Copyright © 2021 the Author(s). Published by PNAS.)
- Published
- 2021
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11. Topographic Anatomy of the Zygomatico-Orbital Artery: Implications for Improving the Safety of Temporal Augmentation.
- Author
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Liu S, Yan W, Wang G, Zhao R, Qiu H, Cao L, and Wang H
- Subjects
- Adult, Aged, Cadaver, Contrast Media administration & dosage, Dermal Fillers administration & dosage, Female, Humans, Imaging, Three-Dimensional, Injections, Subcutaneous adverse effects, Male, Middle Aged, Orbit blood supply, Temporal Arteries diagnostic imaging, Temporal Arteries injuries, Tomography, X-Ray Computed, Vascular System Injuries etiology, Zygoma blood supply, Anatomic Variation, Cosmetic Techniques adverse effects, Forehead blood supply, Temporal Arteries abnormalities, Vascular System Injuries prevention & control
- Abstract
Background: Anatomical knowledge of the zygomatico-orbital artery and its most relevant clinical applications is essential for ensuring the safety of filler injection into the temporal region. The purpose of this study was to provide the precise position, detailed course, and relationship with surrounding structures of the zygomatico-orbital artery., Methods: Fifty-eight patients who underwent head contrast-enhanced three-dimensional computed tomography and 10 fresh frozen cadavers were investigated., Results: The zygomatico-orbital artery was identified in 93 percent of the samples in this work. Ninety-four percent of the zygomatico-orbital arteries derived directly from the superficial temporal artery, and the remaining arteries started from the frontal branch of the superficial temporal artery. According to the origin of the zygomatico-orbital artery, it was classified into type I and type II. Type I arteries were then classified into three subtypes. The trunk of the zygomatico-orbital artery was located between the deep temporal fascia and the superficial temporal fascia. Deep branches of the zygomatico-orbital artery pierced the superficial layer of the deep temporal fascia. The zygomatico-orbital artery originated from 11.3 mm in front of the midpoint of the apex of the tragus, and most of its trunks were located less than 20.0 mm above the zygomatic arch. The mean diameter of the zygomatico-orbital artery was 1.2 ± 0.2 mm. There were extensive anastomoses between the zygomatico-orbital artery and various periorbital arteries at the lateral orbital rim., Conclusion: The precise anatomical knowledge of the zygomatico-orbital artery described in this study could be helpful for cosmetic physicians for improving the safety of temporal augmentation., (Copyright © 2021 by the American Society of Plastic Surgeons.)
- Published
- 2021
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12. Warming-driven shifts in ecological control of fish communities in a large northern Chinese lake over 66 years.
- Author
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Bao H, Wang G, Yao Y, Peng Z, Dou H, and Jiang G
- Subjects
- Animals, China, Climate Change, Ecosystem, Fisheries, Fishes, Conservation of Natural Resources, Lakes
- Abstract
Warming, land-use change, and habitat loss are three major threats to aquatic biodiversity worldwide under the influences of anthropogenic disturbances. Positive feedback between warming and bottom-up regulation may cause irreversible ecological regime shifts. Threshold dynamics of interspecific interactions have been rarely studied in freshwater fish communities using threshold community models. Here we use 66 years (1950-2015) of data to link four ecological regime shifts of 9-species fish communities to climatic and land use changes in Lake Hulun, the largest freshwater lake of Northern China. Overfishing caused the collapse of piscivorous fish populations and an ecological regime shift of Lake Hulun in the late 1950s. The first recorded algal bloom of Lake Hulun took place in 1986, with accelerated warming and rapid increases in livestock grazing. The dominance of planktivorous minnow populations reduced fish biodiversity in a nonlinear, threshold manner when annual mean ambient temperature was >0.12 °C. Multivariate environmental vector regression demonstrated that warming, eutrophication, and water-storage reduction (i.e., habitat loss) were related to three ecological regime shifts of Lake Hulun from 1960 to 2015. Multivariate autoregressive models (MAR) did not detect predation by piscivorous fish in Lake Hulun after 1960. Threshold MAR models indicated that dominant minnow populations and other prey fish populations switched from top-down to bottom-up control during the 1980s. Sustained positive feedback between warming, the dominance of planktivorous fish populations, and bottom-up regulation caused predator-prey role reversal, and probably resulted in three regime shifts of Lake Hulun over 56 years. This study provides a comprehensive analysis of ecological regime shifts in Hulun Lake fish communities, and has potential implications for fish species living in similar environments that are subject to global warming, land-use changes, and overfishing., Competing Interests: Declaration of competing interest There are no competing interests., (Copyright © 2021 Elsevier B.V. All rights reserved.)
- Published
- 2021
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13. LncRNA FENDRR Inhibits ox-LDL Induced Mitochondrial Energy Metabolism Disorder in Aortic Endothelial Cells via miR-18a-5p/PGC-1 α Signaling Pathway.
- Author
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Wang G, Yang Y, Ma H, Shi L, Jia W, Hao X, and Liu W
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- Adenosine Triphosphate metabolism, Aorta drug effects, Apoptosis, Atherosclerosis metabolism, Endothelial Cells drug effects, Energy Metabolism drug effects, Humans, MicroRNAs metabolism, Mitochondria drug effects, Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha metabolism, Reactive Oxygen Species metabolism, Signal Transduction drug effects, Up-Regulation, Aorta metabolism, Endothelial Cells metabolism, Energy Metabolism physiology, Lipoproteins, LDL pharmacology, Mitochondria metabolism, RNA, Long Noncoding metabolism, Signal Transduction physiology
- Abstract
Atherosclerosis (AS) is the main cause of morbidity and mortality in the world. Mitochondrial dysfunction is closely related to AS. At present, several signaling pathways related to mitochondrial dysfunction have been found, one of which is around PGC-1 α . PGC-1 α is a transcription activator, which is related to mitochondrial biogenesis and antioxidant defense. In this study, we explored the effect of miR-18a-5p/PGC-1 α signaling pathway on mitochondrial energy metabolism in HAECs with ox-LDL treatment. The results showed that the mitochondrial energy metabolism disorder in HAECs treated by ox-LDL was related to the downregulation of LncRNA FENDRR and PGC-1 α . FENDRR could reverse ox-LDL induced mitochondrial energy metabolism disorder and upregulate the PGC-1 α expression. FENDRR could be used as ceRNA to inhibit the miR-18a-5p expression and reduce the negative regulation of miR-18a-5p on PGC-1 α . Downregulation of miR-18a-5p expression or upregulation of PGC-1 α in ox-LDL treated HAECs could reverse mitochondrial energy metabolism disorder. In conclusion, these findings suggested that FENDRR/miR-18a-5p/PGC-1 α signaling pathway regulated mitochondrial energy metabolism in HAECs; ox-LDL downregulated the expression of PGC-1 α and cause mitochondrial energy metabolism disorder by inhibiting this signal pathway., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Wang, Yang, Ma, Shi, Jia, Hao and Liu.)
- Published
- 2021
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14. Deeply digging the interaction effect in multiple linear regressions using a fractional-power interaction term.
- Author
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Li X, Li B, Wang G, Zhan X, and Holyoak M
- Abstract
In multiple regression Y ~ β
0 + β1 X1 + β2 X2 + β3 X1 X2 + ɛ., the interaction term is quantified as the product of X1 and X2 . We developed fractional-power interaction regression (FPIR), using βX1 M X2 N as the interaction term. The rationale of FPIR is that the slopes of Y-X1 regression along the X2 gradient are modeled using the nonlinear function (Slope = β1 + β3 MX1 M-1 X2 N ), instead of the linear function (Slope = β1 + β3 X2 ) that regular regressions normally implement. The ranges of M and N are from -56 to 56 with 550 candidate values, respectively. We applied FPIR using a well-studied dataset, nest sites of the crested ibis ( Nipponia nippon ).We further tested FPIR by other 4692 regression models. FPIRs have lower AIC values (-302 ± 5003.5) than regular regressions (-168.4 ± 4561.6), and the effect size of AIC values between FPIR and regular regression is 0.07 (95% CI: 0.04-0.10). We also compared FPIR with complex models such as polynomial regression, generalized additive model, and random forest. FPIR is flexible and interpretable, using a minimum number of degrees of freedom to maximize variance explained. We have provided a new R package, interactionFPIR, to estimate the values of M and N , and suggest using FPIR whenever the interaction term is likely to be significant. • Introduced fractional-power interaction regression (FPIR) as Y ~ β0 + β1 X1 + β2 X2 + β3 X1 M X2 N + ɛ to replace the current regression model Y ~ β0 + β1 X1 + β2 X2 + β3 X1 X2 + ɛ; • Clarified the rationale of FPIR, and compared it with regular regression model, polynomial regression, generalized additive model, and random forest using regression models for 4692 species; • Provided an R package, interactionFPIR, to calculate the values of M and N , and other model parameters., Competing Interests: The Authors confirm that there are no conflicts of interest., (© 2020 The Authors. Published by Elsevier B.V.)- Published
- 2020
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15. Relationships between survival and habitat suitability of semi-aquatic mammals.
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Barela I, Burger LM, Taylor J, Evans KO, Ogawa R, McClintic L, and Wang G
- Abstract
Spatial distribution and habitat selection are integral to the study of animal ecology. Habitat selection may optimize the fitness of individuals. Hutchinsonian niche theory posits the fundamental niche of species would support the persistence or growth of populations. Although niche-based species distribution models (SDMs) and habitat suitability models (HSMs) such as maximum entropy (Maxent) have demonstrated fair to excellent predictive power, few studies have linked the prediction of HSMs to demographic rates. We aimed to test the prediction of Hutchinsonian niche theory that habitat suitability (i.e., likelihood of occurrence) would be positively related to survival of American beaver ( Castor canadensis ), a North American semi-aquatic, herbivorous, habitat generalist. We also tested the prediction of ideal free distribution that animal fitness, or its surrogate, is independent of habitat suitability at the equilibrium. We estimated beaver monthly survival probability using the Barker model and radio telemetry data collected in northern Alabama, United States from January 2011 to April 2012. A habitat suitability map was generated with Maxent for the entire study site using landscape variables derived from the 2011 National Land Cover Database (30-m resolution). We found an inverse relationship between habitat suitability index and beaver survival, contradicting the predictions of niche theory and ideal free distribution. Furthermore, four landscape variables selected by American beaver did not predict survival. The beaver population on our study site has been established for 20 or more years and, subsequently, may be approaching or have reached the carrying capacity. Maxent-predicted increases in habitat use and subsequent intraspecific competition may have reduced beaver survival. Habitat suitability-fitness relationships may be complex and, in part, contingent upon local animal abundance. Future studies of mechanistic SDMs incorporating local abundance and demographic rates are needed., Competing Interests: The authors have no conflict of interest related to this work., (© 2020 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.)
- Published
- 2020
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16. Latitude and daily-weather effects on gobbling activity of wild turkeys in Mississippi.
- Author
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Palumbo MD, Vilella FJ, Wang G, Strickland BK, Godwin D, Dixon PG, Rubin BD, and Lashley MA
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- Animals, Animals, Wild, Female, Male, Probability, Seasons, Turkeys, Weather
- Abstract
Weather has been recognized as a density independent factor influencing the abundance, distribution, and behavior of vertebrates. Male wild turkeys' (Meleagris gallopavo) breeding behavior includes vocalizations and courtship displays to attract females, the phenology of which can vary with latitude. State biologists design spring turkey-hunting season frameworks centered on annual vocalization patterns to maximize hunter engagement. The Mississippi Department of Wildlife, Fisheries, and Parks has traditionally instituted a statewide, 7-week, spring harvest season. However, hunters routinely argue that different peaks in gobbling activity across the state exist. The objective of this study was to determine whether differences in peak gobbling activity existed across a latitudinal gradient of Mississippi and assess the effect of weather on gobbling. During 2008 and 2009, we conducted a statewide gobbling survey. We used generalized additive mixed models to describe the probability and frequency of gobbling activity within northern and southern regions of the state. We also investigated the effect of daily weather conditions on gobbling activity. Our results revealed an approximate 10-14-day difference in peak gobbling activity between southern and northern Mississippi. The majority of all gobbling activity occurred within the current spring harvest framework. Perhaps more importantly, gobbling activity was more prevalent on days of regionally dry conditions (i.e., less humid) according to the Spatial Synoptic Classification. Our results provide information on gobbling activity phenology relative to hunting-season dates and weather-response information. Our approach may be particularly applicable in states with relatively shorter seasons or highly variable daily weather conditions that moderate gobbling frequency.
- Published
- 2019
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17. Anti-Corrosion Property of Glass Flake Reinforced Chemically Bonded Phosphate Ceramic Coatings.
- Author
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Yan G, Wang M, Sun T, Li X, Wang G, and Yin W
- Abstract
Glass flake (GF) was used as the reinforcement in chemically bonded phosphate ceramic (CBPC) coatings to promote anti-corrosion property. The crystalline phase, curing behavior, micromorphology and electrochemical performance of the coatings were studied. The results indicate that with the addition of magnesia (MgO), a new bonding phase (Mg
3 (PO4 )2 ) can be formed, which can help the CBPCs achieve a more compact and denser structure. The effect of the magnesia and the GF additives on curing behavior is obvious: the heat of reaction of the phosphate ceramic materials increases with the addition of the magnesia and the GF, which emphasizes the higher crosslinking density in the phosphate ceramic materials. The phosphate ceramic coatings with the magnesia have a higher impedance value compared with the neat phosphate ceramic coating, while the highest impedance value is obtained with increased content of GF. The corrosion mechanism is mainly contributed by the new bonding phase and GF particles, which can hinder the permeation pathway and make the permeation more circuitous.- Published
- 2019
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18. Machine learning of large-scale spatial distributions of wild turkeys with high-dimensional environmental data.
- Author
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Farrell A, Wang G, Rush SA, Martin JA, Belant JL, Butler AB, and Godwin D
- Abstract
Species distribution modeling often involves high-dimensional environmental data. Large amounts of data and multicollinearity among covariates impose challenges to statistical models in variable selection for reliable inferences of the effects of environmental factors on the spatial distribution of species. Few studies have evaluated and compared the performance of multiple machine learning (ML) models in handling multicollinearity. Here, we assessed the effectiveness of removal of correlated covariates and regularization to cope with multicollinearity in ML models for habitat suitability. Three machine learning algorithms maximum entropy (MaxEnt), random forests (RFs), and support vector machines (SVMs) were applied to the original data (OD) of 27 landscape variables, reduced data (RD) with 14 highly correlated covariates being removed, and 15 principal components (PC) of the OD accounting for 90% of the original variability. The performance of the three ML models was measured with the area under the curve and continuous Boyce index. We collected 663 nonduplicated presence locations of Eastern wild turkeys ( Meleagris gallopavo silvestris ) across the state of Mississippi, United States. Of the total locations, 453 locations separated by a distance of ≥2 km were used to train the three ML algorithms on the OD, RD, and PC data, respectively. The remaining 210 locations were used to validate the trained ML models to measure ML performance. Three ML models had excellent performance on the RD and PC data. MaxEnt and SVMs had good performance on the OD data, indicating the adequacy of regularization of the default setting for multicollinearity. Weak learning of RFs through bagging appeared to alleviate multicollinearity and resulted in excellent performance on the OD data. Regularization of ML algorithms may help exploratory studies of the effects of environmental factors on the spatial distribution and habitat suitability of wildlife., Competing Interests: The authors have no conflict of interest related to this work.
- Published
- 2019
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19. Rheological Behavior and Microstructure Characteristics of SCC Incorporating Metakaolin and Silica Fume.
- Author
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Ling G, Shui Z, Sun T, Gao X, Wang Y, Sun Y, Wang G, and Li Z
- Abstract
This study explores the effects of metakaolin (MK) and silica fume (SF) on rheological behaviors and microstructure of self-compacting concrete (SCC). The rheology, slump flow, V-funnel, segregation degree (SA), and compressive strength of SCC are investigated. Microstructure characteristics, including hydration product and pore structure, are also studied. The results show that adding MK and SF instead of 4%, 6% and 8% fly ash (FA) reduces flowability of SCC; this is due to the fact that the specific surface area of MK and SF is larger than FA, and the total water demand increases as a result. However, the flowability increases when replacement ratio is 2%, as the small MK and SF particles will fill in the interstitial space of mixture and more free water is released. The fluidity, slump flow, and SA decrease linearly with the increase of yield stress. The total amount of SF and MK should be no more than 6% to meet the requirement of self-compacting. Adding MK or SF to SCC results in more hydration products, less Ca(OH)₂ and refinement of pore structure, leading to obvious strength and durability improvements. When the total dosage of MK and SF admixture is 6%, these beneficial effects on workability, mechanical performance, and microstructure are more significant when SF and MK are applied together.
- Published
- 2018
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20. Scale-dependent home range optimality for a solitary omnivore.
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Gantchoff M, Wang G, Beyer D, and Belant J
- Abstract
Spatial and temporal heterogeneity are fundamental mechanisms structuring home ranges. Under optimality, an individual should structure their space use economically to maximize fitness. We evaluated support for three hypotheses related to range optimality in American black bears ( Ursus americanus ), predicting (a) range location on a landscape will correspond with high vegetation productivity, (b) increasing forest fragmentation will result in larger ranges, and (c) increasing proportion of forest and/or mean vegetation productivity will result in smaller ranges. We used black bear radio telemetry data from Michigan (2009-2015), Missouri (2010-2016), and Mississippi (2008-2017), USA. Annual space use excluded winter, and we separated seasonal space use into spring, summer, and fall. We collected data from 143 bears (80 females, 63 males), resulting in 97 annual and 538 seasonal ranges. We used generalized linear mixed models to evaluate productivity (estimated through Normalized Difference Vegetation Index [NDVI]) selection, and range size (km
2 ) variation between individuals. At the annual scale, black bears consistently selected areas with greater vegetation productivity than the surrounding landscape; yet selection weakened and was more variable seasonally. Opposite to our prediction, we found that increasing fragmentation consistently resulted in smaller ranges; non-forested land covers and forest edges might provide greater abundance or more diverse foods for bears. Ranges with a greater proportion of forest were smaller, likely reflecting an increase in food and cover which could reduce movements, yet there was no support for more productive ranges also being smaller as expected from an area minimizing strategy. Black bears displayed a scale-dependent space use strategy: at larger spatial and temporal scales, productivity acted as the strongest limiting factor and energy maximizing was the dominant strategy, while an area minimizing strategy was exhibited seasonally. We revealed consistent, scale-dependent responses by black bears to environmental conditions, demonstrating the intrinsic plasticity of this adaptable omnivore.- Published
- 2018
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21. Perineal midline vertical incision verses inverted-U incision in the urethroplasty: which is better?
- Author
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Lin Y, Luo D, Liao B, Yang T, Tian Y, Jin T, Wang G, Zhou H, Li H, and Wang K
- Subjects
- Adult, China, Humans, Male, Regression Analysis, Retrospective Studies, Surgical Wound Infection etiology, Treatment Outcome, Urethra pathology, Urethral Stricture pathology, Surgical Wound, Urethra surgery, Urethral Stricture surgery, Urologic Surgical Procedures, Male methods
- Abstract
Objective: To compare postoperative outcomes between the perineal inverted-U and the vertical midline incision approaches of the urethroplasty and clarify them via gross anatomy., Patients and Methods: A total of 461 male patients, from Jan. 2006 to Jun. 2014, who underwent the urethroplasty via perineal midline vertical or inverted-U incision approach were recruited retrospectively. By match pairing for etiology and stricture length, 410 patients from two groups (205 for each group) were selected. Anatomy experiments were also performed. Outcome measurements and statistical analysis: the Chi-square, Student's t and binary logistic regression analyses were performed to compare the operative and postoperative data on the two groups., Results: With regard to patients with bulbar urethral stricture, the rate of surgical site infection (SSI) in perineal inverted-U group was 18.6% while 1.9% in the midline vertical group (p < 0.001). As for patients with posterior urethral stricture, the rate of SSI in the perineal inverted-U group was 16.4% while 3.1% in the midline vertical group (p = 0.001). Mean hospital stay between both groups were 15.8 ± 9.0 vs. 12.7 ± 3.8 days (p < 0.001). Anatomy experiments showed the number of damaged vessels and nerves involved in the inverted-U incision were approximately 1.6 to 2.0 folds more than the vertical midline, but the visual operation fields are similar between two approaches., Conclusions: The perineal midline vertical incision is a safer approach with fewer SSI and shorter hospital stay than the perineal inverted-U incision for bulbar and posterior urethroplasty.
- Published
- 2018
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22. Identification of biomarkers of venous thromboembolism by bioinformatics analyses.
- Author
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Wang G, Zhao W, Yang Y, Yang G, Wei Z, and Guo J
- Subjects
- Computational Biology, Databases, Genetic, Down-Regulation, Genetic Markers genetics, Humans, Protein Interaction Maps, Signal Transduction genetics, Up-Regulation, Genes, p53, NAD genetics, NLR Proteins genetics, Ribosomal Proteins genetics, Venous Thromboembolism genetics
- Abstract
Venous thromboembolism (VTE) is a common vascular disease and a major cause of mortality. This study intended to explore the biomarkers associated with VTE by bioinformatics analyses.Based on Gene Expression Omnibus (GEO) database, the GSE19151 expression profile data were downloaded. The differentially expressed genes (DEGs) between single VTE (sVTE)/recurrent VTE (rVTE) and control were identified. Then, pathway enrichment analysis of DEGs were performed, followed by protein-protein interaction (PPI) network construction.Total 433 upregulated and 222 downregulated DEGs were obtained between sVTE and control samples. For rVTE versus control, 625 upregulated and 302 downregulated DEGs were identified. The overlap DEGs were mainly enriched in the pathways related to ribosome, cancer, and immune disease. The DEGs specific to rVTE were enriched in several pathways, such as nod-like receptor signaling pathway. In the PPI network, 2 clusters of VTE genes, including ribosomal protein family genes and NADH family-ubiquinol-cytochrome genes, were identified, such as ribosomal protein L9 (RPL9), RPL5, RPS20, RPL23, and tumor protein p53 (TP53).The nod-like receptor signaling pathway, ribosomal protein family genes, such as RPL9, RPL5, RPS20, and RPL23, and DEG of TP53 may have the potential to be used as targets for diagnosis and treatment of VTE.
- Published
- 2018
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23. Birth date promotes a tortoise or hare tactic for body mass development of a long-lived male ungulate.
- Author
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Michel ES, Demarais S, Strickland BK, and Wang G
- Subjects
- Animals, Female, Lactation, Male, Reproduction, Deer, Hares, Turtles
- Abstract
Maternal and early-life influences may affect life-long individual phenotype, potentially influencing reproductive success. However, some individuals may compensate for a poor start to life, which may improve longevity and reproductive success later in life. We developed four models to assess whether maternal characteristics (age, body mass and previous year cumulative lactation demand) and/or birth date influenced a long-lived mammal's phenotype to maturity. We used a directional separation analysis to assess the relative influence of each maternal characteristic and birth date on captive male white-tailed deer (Odocoileus virginianus) body mass and antler size. We found that birth date was the only characteristic that persistently influenced male body mass. Depending on when offspring were born, they used alternative tactics to increase their body mass. Birth date positively influenced body mass at 1, 2 and 3 years of age-indicating males displayed faster growth and compensated for late birth (hare tactic). However, early-, heavy-born males were heavy juveniles, and juvenile body mass positively influenced mature body mass (slow but steady growth; tortoise tactic). Our findings provide a first evidence that a long-lived ungulate can display alternative tactics to achieve heavy body mass; individuals are either born early and heavy and are heavy throughout life (tortoise), or light, late-born individuals compensate for a poor start in life by growing at a faster rate to equal or surpass the body mass of early-born individuals (hare). Either tactic may be viable if it influences reproductive success as body mass positively influences access to mates in ungulates.
- Published
- 2018
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24. Systematic analysis of the molecular mechanism of microRNA-124 in hepatoblastoma cells.
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Wang G, Liu H, Wei Z, Jia H, Liu Y, and Liu J
- Abstract
The present study aimed to identify the molecular mechanisms of microRNA-124 (miRNA-124/miR-124) in hepatoblastoma. The GSE6207 microarray dataset, obtained from the Gene Expression Omnibus database, included samples extracted from HepG2 cells transfected with miR-124 duplex (the experimental group) or negative control (the control group) at 4, 8, 16, 24, 32, 72 and 120 h after transfection. Differentially expressed genes (DEGs) were screened between the two groups. miR-124 activity was inferred based on the expression of its target genes. The mRNAs targeted by miR-124 were predicted and a miR-124-target mRNA network was constructed. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed for the target genes. The number of DEGs was highest at 72 h. The experimental group had higher miR-124 activity than that of the control group at 4, 8, 16, 24 and 120 h. Small GTPase-mediated signal transduction and Ras protein signal transduction were significant GO terms enriched with syndecan binding protein ( SDCBP ), Ras homolog family member G ( RHOG ) and Rho-GDP dissociation inhibitor-α ( ARHGDIA ). Regulation of actin cytoskeleton, D-glutamine and D-glutamate metabolism, and axon guidance were significant pathways. Axon guidance pathway was associated with neuropilin ( NRP1 ), MET proto-oncogene, receptor tyrosine kinase (MET) and semaphorin 7A, GPI membrane anchor ( SEMA7A ). Small GTPase-mediated signal transduction, Ras protein signal transduction, regulation of actin cytoskeleton pathway, D-glutamine and D-glutamate metabolism pathway, axon guidance pathway, SDCBP, RHOG, ARHGDIA, NRP1, SEMA7A , and MET may be implicated in the underlying mechanisms of miR-124 overexpression in hepatoblastoma.
- Published
- 2017
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25. Restricted cross-scale habitat selection by American beavers.
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Francis RA, Taylor JD, Dibble E, Strickland B, Petro VM, Easterwood C, and Wang G
- Abstract
Animal habitat selection, among other ecological phenomena, is spatially scale dependent. Habitat selection by American beavers Castor canadensis (hereafter, beaver) has been studied at singular spatial scales, but to date no research addresses multi-scale selection. Our objectives were to determine if beaver habitat selection was specialized to semiaquatic habitats and if variables explaining habitat selection are consistent between landscape and fine spatial scales. We built maximum entropy (MaxEnt) models to relate landscape-scale presence-only data to landscape variables, and used generalized linear mixed models to evaluate fine spatial scale habitat selection using global positioning system (GPS) relocation data. Explanatory variables between the landscape and fine spatial scale were compared for consistency. Our findings suggested that beaver habitat selection at coarse (study area) and fine (within home range) scales was congruent, and was influenced by increasing amounts of woody wetland edge density and shrub edge density, and decreasing amounts of open water edge density. Habitat suitability at the landscape scale also increased with decreasing amounts of grass frequency. As territorial, central-place foragers, beavers likely trade-off open water edge density (i.e., smaller non-forested wetlands or lodges closer to banks) for defense and shorter distances to forage and obtain construction material. Woody plants along edges and expanses of open water for predator avoidance may limit beaver fitness and subsequently determine beaver habitat selection.
- Published
- 2017
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26. Restricted dispersal determines fine-scale spatial genetic structure of Mongolian gerbils.
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Wang G, Liu W, Wang Y, Wan X, and Zhong W
- Abstract
Restricted gene flow may cause positive spatial genetic autocorrelation of animal populations at fine spatial scales. The Mongolian gerbil Meriones unguiculatus is a territorial, social rodent. Territoriality may create social fences to restrict dispersal or gene flow of Mongolian gerbils to a short distance. Restricted dispersal may differentiate fine-scale spatial genetic structure of populations with increasing distances (i.e., isolation by distance [IBD]). Competition for mates and inbreeding avoidance may result in equal dispersal propensity and subsequently similar spatial genetic autocorrelation between males and females of monogamous gerbils. We genotyped 327 gerbils, live captured from 26 burrow systems on a 9-ha plot in northcentral Inner Mongolia, China, using seven microsatellite loci. Spatial genetic autocorrelation was positive within 80 m and became negative from 80 m to 200 m, suggesting restricted gene flow. Inter-group genetic and geographic distances were related positively, supporting the IBD model. Live trapping data demonstrated equal dispersal propensities of male and female gerbils. Restricted dispersal and social organization may determine fine-scale spatial population genetic structure of social rodents.
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- 2017
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27. Seasonal effects of wind conditions on migration patterns of soaring American white pelican.
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Gutierrez Illan J, Wang G, Cunningham FL, and King DT
- Subjects
- Animals, Flight, Animal, North America, Animal Migration, Birds physiology, Seasons, Wind
- Abstract
Energy and time expenditures are determinants of bird migration strategies. Soaring birds have developed migration strategies to minimize these costs, optimizing the use of all the available resources to facilitate their displacement. We analysed the effects of different wind factors (tailwind, turbulence, vertical updrafts) on the migratory flying strategies adopted by 24 satellite-tracked American white pelicans (Pelecanus erythrorhynchos) throughout spring and autumn in North America. We hypothesize that different wind conditions encountered along migration routes between spring and autumn induce pelicans to adopt different flying strategies and use of these wind resources. Using quantile regression and fine-scale atmospheric data, we found that the pelicans optimized the use of available wind resources, flying faster and more direct routes in spring than in autumn. They actively selected tailwinds in both spring and autumn displacements but relied on available updrafts predominantly in their spring migration, when they needed to arrive at the breeding regions. These effects varied depending on the flying speed of the pelicans. We found significant directional correlations between the pelican migration flights and wind direction. In light of our results, we suggest plasticity of migratory flight strategies by pelicans is likely to enhance their ability to cope with the effects of ongoing climate change and the alteration of wind regimes. Here, we also demonstrate the usefulness and applicability of quantile regression techniques to investigate complex ecological processes such as variable effects of atmospheric conditions on soaring migration.
- Published
- 2017
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28. Protocol for Assessing the Relative Effects of Environment and Genetics on Antler and Body Growth for a Long-lived Cervid.
- Author
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Michel ES, Flinn EB, Demarais S, Strickland BK, Wang G, and Dacus CM
- Subjects
- Animal Nutritional Physiological Phenomena, Animals, Antlers anatomy & histology, Body Size genetics, Diet, Ecosystem, Female, Male, Mississippi, Phenotype, Soil, Telemetry instrumentation, Telemetry methods, Antlers growth & development, Deer genetics, Deer growth & development
- Abstract
Cervid phenotype can be placed into one of two categories: efficiency, which promotes survival over extravagant morphometric growth, and luxury, which promotes growth of large weaponry and body size. Populations of the same species display each phenotype depending on environmental conditions. Although antler and body size of male white-tailed deer (Odocoileus virginianus) varies by physiographic region in Mississippi, USA and is strongly correlated with regional variation in nutritional quality, the effects of population-level genetics from native stocks and previous re-stocking efforts cannot be disregarded. This protocol describes how we designed a controlled study, where other factors that influence phenotype, such as age and nutrition, are controlled. We brought wild-caught pregnant females and six-month-old fawns from three distinct physiographic regions in Mississippi, USA to the Mississippi State University Rusty Dawkins Memorial Deer Unit. Deer from the same region were bred to produce a second generation of offspring, allowing us to assess generational responses and maternal effects. All deer ate the same high-quality (20% crude protein deer pellet) diet ad libitum. We uniquely marked each neonate and recorded body mass, hind foot, and total body length. Each subsequent fall, we sedated individuals via remote injection and sampled the same morphometrics plus antlers of adults. We found that all morphometrics increased in size from first to second generation, with full compensation of antler size (regional variation no longer present) and partial compensation of body mass (some evidence of regional variation) evident in the second generation. Second generation males that originated from our poorest quality soil region displayed about a 40% increase in antler size and about a 25% increase in body mass when compared to their wild harvested counterparts. Our results suggest phenotypic variation of wild male white-tailed deer in Mississippi are more related to differences in nutritional quality than population-level genetics.
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- 2017
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29. Screening of potential gene markers for predicting carotid atheroma plaque formation using bioinformatics approaches.
- Author
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Wang G, Kuai D, Yang Y, Yang G, Wei Z, and Zhao W
- Subjects
- Carotid Artery Diseases diagnosis, Carotid Artery Diseases metabolism, Databases, Genetic, Down-Regulation, Gene Regulatory Networks, Genetic Markers genetics, Genomics, Humans, Plaque, Atherosclerotic diagnosis, Plaque, Atherosclerotic metabolism, Prognosis, Transcription Factors genetics, Transcription Factors metabolism, Up-Regulation, Carotid Artery Diseases genetics, Plaque, Atherosclerotic genetics, Protein Interaction Maps, Transcriptome
- Abstract
The present study aimed to investigate potential gene markers for predicting the formation of carotid atheroma plaques using high‑throughput bioinformatics methods. The GSE43292 gene expression profile was downloaded from the Gene Expression Omnibus database. Following data processing, differentially expressed genes (DEGs) were screened using a paired t‑test in the Linear Models for Microarray Data package with the criteria of a false discovery rate of P<0.05 and |log2 fold‑change| ≥0.58, followed by functional enrichment, protein‑protein interaction (PPI) network construction, key node and module analysis, and prediction of transcription factors (TFs) targeting genes in the significant modules. The results revealed that the gene expression profiles from 32 paired samples of carotid atheroma plaque tissue and macroscopically intact tissue were obtained, based on which 886 DEGs, including 513 upregulated genes and 373 downregulated genes, were identified. The upregulated and downregulated gene sets were enriched in 24 and 13 pathways, respectively. The PPI network constructed with these DEGs comprised 35 key nodes with degrees ≥20, among which spleen tyrosine kinase (SYK), LYN and phosphatidylinositol‑4,5‑bisphosphate 3‑kinase catalytic subunit γ (PIK3CG) were the three highest. A significant module was mined in the PPI network, which consisted of 29 DEGs targeted by 11 TFs. The DEGs between the carotid atheroma plaque and macroscopically intact tissue samples may be involved in carotid atherogenesis. Key nodes in the PPI network constructed from these DEGs and the genes involved in the significant module, including SYK, LYN and PIK3CG, are promising for the prediction of carotid plaque formation.
- Published
- 2017
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30. Advances and Environmental Conditions of Spring Migration Phenology of American White Pelicans.
- Author
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King DT, Wang G, Yang Z, and Fischer JW
- Subjects
- Animals, Breeding, Female, Geography, Male, Population Dynamics, Animal Migration physiology, Birds physiology, Environment, Seasons
- Abstract
Spring migration phenology of birds has advanced under warming climate. Migration timing of short-distance migrants is believed to be responsive to environmental changes primarily under exogenous control. However, understanding the ecological causes of the advancement in avian spring migration phenology is still a challenge due to the lack of long-term precise location data. We used 11 years of Global Positioning System relocation data to determine four different migration dates of the annual migration cycle of the American white pelican (Pelecanus erythrorhynchos), a short-distance migrant. We also tested the hypothesis that increases in winter temperature and precipitation on the wintering grounds would advance pelican spring migration. Pelican spring departures and arrivals advanced steadily from 2002 to 2011. Spring departure timing exhibited high repeatability at the upper end of migration timing repeatability reported in literature. However, individual spring departure and arrival dates were not related to winter daily temperature, total winter precipitation, and detrended vegetation green-up dates indexed by the normalized difference vegetation index. Despite high repeatability, the observed between-year variation of spring departure dates was still sufficient for the advancement of spring departure timing.
- Published
- 2017
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- View/download PDF
31. Improved nutrition cues switch from efficiency to luxury phenotypes for a long-lived ungulate.
- Author
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Michel ES, Flinn EB, Demarais S, Strickland BK, Wang G, and Dacus CM
- Abstract
Cervid phenotype can be categorized as efficiency, which promotes survival but not extravagant growth, or luxury which promotes growth of large weaponry and body size. Although nutritional variation greatly influences these phenotypic forms, the potential for subspecies-linked genetic or founder effects from restocking efforts of harvested species has not been eliminated. We measured intergenerational phenotypic change of males in response to improved nutrition in three captive-reared populations of white-tailed deer. Study animals were offspring of females captured from three regions displaying variation in antler and body size as well as nutritional variation. We fed all animals a high-quality diet and measured antler and body size for two generations. We predicted that improved long-term nutrition would cue a switch from efficiency to luxury phenotype for all populations and that regional compensation of antler and body size would occur. Improved nutrition positively influenced all measures of antler and body size; however, changes varied in magnitude. Antler size was more responsive than body size. Improved nutrition also facilitated regional compensation of antler size and partial compensation of body size. Our results show that improved long-term nutrition cues a shift from efficiency to luxury phenotype in a long-lived cervid with weaponry being more responsive than body size. Compensation of antler size suggests that weaponry is greatly influenced by nutrition and is not restricted by subspecies-linked genetic or founder effects from restocking efforts related to our regional populations. Therefore, strategies to improve cervid antler and body size should include habitat management that elevates long-term diet quality.
- Published
- 2016
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32. Successive sheep grazing reduces population density of Brandt's voles in steppe grassland by altering food resources: a large manipulative experiment.
- Author
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Li G, Yin B, Wan X, Wei W, Wang G, Krebs CJ, and Zhang Z
- Subjects
- Animal Feed, Animals, Biomass, Body Weight, Ecology, Female, Livestock, Male, Population Density, Arvicolinae physiology, Biodiversity, Diet, Grassland, Herbivory, Plants chemistry, Sheep
- Abstract
Livestock grazing has shaped grassland ecosystems around the world. Previous studies indicated grazing showed various impacts on small rodents; however, most studies were conducted over 1-2 years without controlling for confounding factors such as immigration/emigration and predation in rodents. Brandt's voles (Lasiopodomys brandtii) are generally recognized as pests because of food overlap with domestic herbivores, but are also important for biodiversity conservation because they provide nests or food to many birds. Fully understanding the ecological relationship between domestic herbivores and small mammals is essential to making ecosystem management decisions. To address these needs, we carried out a field experiment during the period 2010-2013 to assess the effects of sheep grazing on vegetation and the population density of Brandt's voles along a gradient of three grazing intensities by using 12 large-scale enclosures. Responses of Brandt's voles to livestock grazing varied with grazing intensity and year. As compared to the control group, sheep grazing had no effect on vole abundance in the first year but an overall negative effect on vole abundance in the following 3 years. Successive grazing caused decreases in survival and male body mass of voles, but had no significant effect on fecundity. Negative effects of grazing were associated with a grazing-induced deterioration in both food quantity (reflected by biomass and cover of less-preferred plants), and food quality (measured by tannin and total phenol content). Our findings highlight the urgent need for more flexible management of yearly rotational grazing to optimize livestock production while maintaining species diversity and ecosystem health.
- Published
- 2016
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33. New hope for the survival of the Amur leopard in China.
- Author
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Jiang G, Qi J, Wang G, Shi Q, Darman Y, Hebblewhite M, Miquelle DG, Li Z, Zhang X, Gu J, Chang Y, Zhang M, and Ma J
- Subjects
- Animals, China, Ecosystem, Geography, Models, Biological, Population Density, Predatory Behavior, Probability, Survival Analysis, Conservation of Natural Resources, Panthera physiology
- Abstract
Natural range loss limits the population growth of Asian big cats and may determine their survival. Over the past decade, we collected occurrence data of the critically endangered Amur leopard worldwide and developed a distribution model of the leopard's historical range in northeastern China over the past decade. We were interested to explore how much current range area exists, learn what factors limit their spatial distribution, determine the population size and estimate the extent of potential habitat. Our results identify 48,252 km(2) of current range and 21,173.7 km(2) of suitable habitat patches and these patches may support 195.1 individuals. We found that prey presence drives leopard distribution, that leopard density exhibits a negative response to tiger occurrence and that the largest habitat patch connects with 5,200 km(2)of Russian current range. These insights provide a deeper understanding of the means by which endangered predators might be saved and survival prospects for the Amur leopard not only in China, but also through imperative conservation cooperation internationally.
- Published
- 2015
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34. Effects of weather and landscape on the equine West Nile virus infection risk in Mississippi, USA.
- Author
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Wang G
- Subjects
- Animals, Bayes Theorem, Biodiversity, Disease Outbreaks, Humans, Mississippi epidemiology, Risk Factors, Geography, Horse Diseases epidemiology, Horse Diseases virology, Horses virology, Weather, West Nile Fever epidemiology, West Nile Fever veterinary
- Abstract
The West Nile virus (WNv) continues to be a public health concern in North America. Dry weather appears to increase human WNv infection risks, but it is uncertain whether dry weather conditions exert similar effects on the corresponding equine WNv infection. This study assessed the effects of precipitation of the previous year and land cover diversity on the equine WNv risk of Mississippi, USA, at the county level in the year 2002 using Bayesian hierarchical models. The risk estimated for 2002 was found to be inversely related to annual precipitation of the preceding year. Equine WNv risks were lower with greater land cover diversity probably due to the diluting effects of biodiversity. Correlation between the equine and human WNv risks was positive but relatively low. Dry weather conditions of the previous year might reduce mosquito competitors and predators and subsequently increase mosquito abundances and equine WNv risks in agricultural areas with low biodiversity.
- Published
- 2015
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35. Knockdown of SOX18 inhibits the proliferation, migration and invasion of hepatocellular carcinoma cells.
- Author
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Wang G, Wei Z, Jia H, Zhao W, Yang G, and Zhao H
- Subjects
- Apoptosis genetics, Blotting, Western, Carcinoma, Hepatocellular genetics, Carcinoma, Hepatocellular mortality, Cell Line, Tumor, Down-Regulation, Female, Gene Knockdown Techniques, Humans, Kaplan-Meier Estimate, Liver Neoplasms genetics, Liver Neoplasms mortality, Male, Neoplasm Invasiveness genetics, Oligonucleotide Array Sequence Analysis, Polymerase Chain Reaction, RNA, Small Interfering, SOXF Transcription Factors metabolism, Transfection, Carcinoma, Hepatocellular pathology, Cell Movement genetics, Cell Proliferation genetics, Liver Neoplasms pathology, SOXF Transcription Factors genetics
- Abstract
Hepatocellular carcinoma (HCC) is one of the most common malignancies in the world. Recent studies have demonstrated that SOX18 is highly expressed in various types of cancer. In the present study, we found that SOX18 mRNA was overexpressed in HCC compared with non-tumorous tissues. We aimed to explore the effects of SOX18 siRNA on the proliferation, invasion and migration of two HCC cell lines, MHCC97H and HepG2, which overexpress SOX18. We found that SOX18 siRNA significantly inhibited the proliferation and induced cell cycle arrest at the G0/G1 phase. Results of the Transwell assay showed that the migration and invasion of the HCC cells were markedly impaired in the SOX18-knockdown cells. Gene set enrichment analysis (GSEA) showed that KEGG focal adhesion and chemokine signaling pathways were correlated with SOX18 expression. Furthermore, the mRNA and protein levels of RhoA, PDGFB, IGF1R, CCL2, CCL3 and CCL5 were decreased in the SOX18-knockdown cells. Importantly, we demonstrated that upregulation of SOX18 was associated with a poor outcome in HCC patients. These results indicate that SOX18 may serve as a prognostic factor and a promising therapeutic strategy for HCC.
- Published
- 2015
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36. [Preparation of 1 µm non-porous C18 silica gel stationary phase for chiral-pressurized capillary electrochromatography].
- Author
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Lu Y, Wang H, Wang G, Wang Y, Gu X, and Yan C
- Subjects
- Chromatography, Liquid, Silanes, Silica Gel, Silicon Dioxide, beta-Cyclodextrins, Bupropion analysis, Capillary Electrochromatography, Clenbuterol analysis, Metoprolol analysis, Propanolamines analysis
- Abstract
Non-porous C18 silica gel stationary phase (1 µm) was prepared and applied to chiral separation in pressurized capillary electrochromatography (pCEC) for the enantioseparation of various basic compounds. The non-porous silica particles (1 µm) were synthesized using modified St6ber method. C18 stationary phase (1 µm) was prepared by immobilization of chloro-dimethyl-octadecylsilane. Using carboxymethyl-β-cyclodextrin (CM-β-CD) as the chiral additive, the pCEC conditions including the content of acetonitrile (ACN), concentration of buffer, pH, the concentration of chiral additive and flow rate as well as applied voltage were investigated to obtain the optimal pCEC conditions for the separation of four basic chiral compounds. The column provided an efficiency of up to 190,000 plates/m. Bupropion hydrochloride, clenbuterol hydrochloride, metoprolol tartrate, and esmolol hydrochloride were baseline separated under the conditions of 5 mmol/L ammonium acetate buffer at pH 4. 0 with 20% (v/ v) acetonitrile, and 15 mmol/L CM-β-CD as the chiral additive. The applied voltage was 2 kV and flow rate was 0.03 mL/min with splitting ratio of 300:1. The resolution were 1.55, 2.82, 1. 69, 1. 70 for bupropion hydrochloride, clenbuterol hydrochloride, metoprolol tartrate, esmolol hydrochloride, respectively. The C18 coverage was improved by repeating silylation method. The synthesized 1 µm C18 packings have better mechanical strength and longer service life because of the special, non-porous structure. The column used in pCEC mode showed better separation of the racemates and a higher rate compared with those used in the capillary liquid chromatography (cLC) mode. This study provided an alternative way for the method of pCEC enantioseparation with chiral additives in the mobile phase and demonstrated the feasibility of micron particle stationary phase in chiral separation.
- Published
- 2015
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37. Fast quantification of endogenous carbohydrates in plasma using hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry.
- Author
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Zhu B, Liu F, Li X, Wang Y, Gu X, Dai J, Wang G, Cheng Y, and Yan C
- Subjects
- Animals, Carbohydrates blood, Hydrophobic and Hydrophilic Interactions, Rats, Carbohydrates chemistry, Chromatography, Liquid methods, Tandem Mass Spectrometry methods
- Abstract
Endogenous carbohydrates in biosamples are frequently highlighted as the most differential metabolites in many metabolomics studies. A simple, fast, simultaneous quantitative method for 16 endogenous carbohydrates in plasma has been developed using hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry. In order to quantify 16 endogenous carbohydrates in plasma, various conditions, including columns, chromatographic conditions, mass spectrometry conditions, and plasma preparation methods, were investigated. Different conditions in this quantified analysis were performed and optimized. The reproducibility, precision, recovery, matrix effect, and stability of the method were verified. The results indicated that a methanol/acetonitrile (50:50, v/v) mixture could effectively and reproducibly precipitate rat plasma proteins. Cold organic solvents coupled with vortex for 1 min and incubated at -20°C for 20 min were the most optimal conditions for protein precipitation and extraction. The results, according to the linearity, recovery, precision, matrix effect, and stability, showed that the method was satisfactory in the quantification of endogenous carbohydrates in rat plasma. The quantified analysis of endogenous carbohydrates in rat plasma performed excellently in terms of sensitivity, high throughput, and simple sample preparation, which met the requirement of quantification in specific expanded metabolomic studies after the global metabolic profiling research., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2015
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38. Behavioral traits and airport type affect mammal incidents with U.S. civil aircraft.
- Author
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Schwarz KB, Belant JL, Martin JA, DeVault TL, and Wang G
- Subjects
- Animals, Behavior, Animal, Biodiversity, Body Size, Mammals, Seasons, United States, Accidents, Aviation, Aircraft, Airports, Animals, Wild
- Abstract
Wildlife incidents with aircraft cost the United States (U.S.) civil aviation industry >US$1.4 billion in estimated damages and loss of revenue from 1990 to 2009. Although terrestrial mammals represented only 2.3 % of wildlife incidents, damage to aircraft occurred in 59 % of mammal incidents. We examined mammal incidents (excluding bats) at all airports in the Federal Aviation Administration (FAA) National Wildlife Strike Database from 1990 to 2010 to characterize these incidents by airport type: Part-139 certified (certificated) and general aviation (GA). We also calculated relative hazard scores for species most frequently involved in incidents. We found certificated airports had more than twice as many incidents as GA airports. Incidents were most frequent in October (n = 215 of 1,764 total) at certificated airports and November (n = 111 of 741 total) at GA airports. Most (63.2 %) incidents at all airports (n = 1,523) occurred at night but the greatest incident rate occurred at dusk (177.3 incidents/hr). More incidents with damage (n = 1,594) occurred at GA airports (38.6 %) than certificated airports (19.0 %). Artiodactyla (even-toed ungulates) incidents incurred greatest (92.4 %) damage costs (n = 326; US$51.8 million) overall and mule deer (Odocoileus hemionus) was the most hazardous species. Overall, relative hazard score increased with increasing log body mass. Frequency of incidents was influenced by species relative seasonal abundance and behavior. We recommend airport wildlife officials evaluate the risks mammal species pose to aircraft based on the hazard information we provide and consider prioritizing management strategies that emphasize reducing their occurrence on airport property.
- Published
- 2014
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39. [Mechanism research on the lupeol treatment on MCF-7 breast cancer cells based on cell metabonomics].
- Author
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Shi D, Kuang Y, Wang G, Peng Z, Wang Y, and Yan C
- Subjects
- Acyl Coenzyme A, Biomarkers metabolism, Discriminant Analysis, Female, Humans, Leucine, MCF-7 Cells, Breast Neoplasms metabolism, Gas Chromatography-Mass Spectrometry, Metabolomics, Pentacyclic Triterpenes pharmacology
- Abstract
The objective of this research is to investigate the suppressive effects of lupeol on MCF-7 breast cancer cells, and explore its mechanism on inhibiting the proliferation of MCF-7 cells based on cell metabonomics and cell cycle. Gas chromatography-mass spectrometry (GC-MS) was used in the cell metabonomics assay to identify metabolites of MCF-7 cells and MCF-7 cells treated with lupeol. Then, orthogonal partial least squares discriminant analysis (OPLS-DA) was used to process the metabolic data and model parameters of OPLS-DA were as follows: R2Ycum = 0.988, Q2Ycum = 0.964, which indicated that these two groups could be distinguished clearly. The metabolites (VIP (variable importance in the projection) > 1) were analyzed by t-test, and finally, metabolites (t < 0.05) were identified to be biomarkers. Eleven metabolites such as butanedioic acid, phosphoric acid, L-leucine and isoleucine which had a significant contribution to classification were selected and preliminarily identified due to the accurate mass. Cell cycle assay was analyzed by FACSCalibur. Since the cells in the phase of G1 were increased significantly after the treatment of lupeol, we speculated that lupeol has a blocking effect on the generation of succinyl-CoA and the reaction of substrate phosphorylation of tricarboxylic acid cycle of MCF-7 cells. This study provided a novel approach to the mechanism research on the lupeol treatment on MCF-7 breast cancer cells based on cell metabonomics.
- Published
- 2014
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40. Weather entrainment and multispectral diel activity rhythm of desert hamsters.
- Author
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Wan X, Zhang X, Huo Y, and Wang G
- Subjects
- Adaptation, Psychological physiology, Algorithms, Animals, China, Cricetinae, Data Interpretation, Statistical, Desert Climate, Humidity, Photoperiod, Circadian Rhythm physiology, Motor Activity physiology, Phodopus physiology, Weather
- Abstract
The circadian rhythm of animals is an adaptation to predictable variation in environmental conditions. Multiple internal oscillators may allow animals to cope with environmental oscillations in different frequencies. Heat stress and dramatic differences between night and day temperatures are the main selective pressures of the diel activity of desert mammals, particularly small-sized rodents. We tested the hypotheses that the diel activities of desert hamsters (Phodopus roborovskii) would be entrained by ambient humidity and temperature. We predicted that increases in night temperature and humidity would improve the propensity to perform activities of the hamster. We observed hourly activities of desert hamsters under semi natural conditions for 24 consecutive hours, with seven replicates in 7 different days. We fit generalized linear mixed models to observed proportions of active hamsters, temperatures, and relative humidity. Observed diel activities of desert hamsters consisted of three harmonic oscillations in the periodicities of 24 h, 12 h, and 6 h, respectively. Furthermore, probabilities to perform activities were positively related to night temperature and humidity. Therefore, the diel activities of desert hamsters are synchronized by atmospheric humidity, temperatures, and environmental cues of ultradian fluctuations., (Copyright © 2013 Elsevier B.V. All rights reserved.)
- Published
- 2013
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41. Effects of resource dispersion and site familiarity on movements of translocated wild turkeys on fragmented landscapes.
- Author
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Marable MK, Belant JL, Godwin D, and Wang G
- Subjects
- Animals, Ecosystem, Female, Male, Conservation of Natural Resources, Exploratory Behavior, Homing Behavior, Recognition, Psychology, Turkeys
- Abstract
Animals in unfamiliar environments may increase exploratory movements, which may result in predation mortalities (the site familiarity hypothesis). Furthermore, increases in resource dispersion may reduce animal foraging time in small patches, and increase movements and home ranges of animals to acquire sufficient resources (the resource dispersion hypothesis). Little is known regarding effects of site familiarity on translocated birds in fragmented landscapes. We translocated 130 eastern wild turkeys (Meleagris gallapovo silvestris) in a sex ratio of one male to 4 females to 2 study sites that differed in forest fragmentation in MS, USA. Turkeys were captured from sites throughout Mississippi during springs 2009 and 2010. We monitored movements of translocated wild turkeys using radio telemetry. Movement distances and home ranges in 2010 did not differ among birds released in different years, inconsistent with the site familiarity hypothesis. However, movement distances and home ranges of translocated turkeys were greater at the more fragmented site than at the less fragmented site, supporting the resource dispersion hypothesis. Moreover, home range sizes were related positively to within-home-range variability in vegetative greenness measured by the normalized difference vegetation index. Effects of resource dispersion may override effects of site familiarity concerning translocated wild turkeys., (Copyright © 2012 Elsevier B.V. All rights reserved.)
- Published
- 2012
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42. High intensity training induces alteration of the ubiquitin-proteasome system gene expression profile and structural changes in the ovaries.
- Author
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Xiong R, Ren X, Wang G, Chen G, Yang H, Yuan Q, and Zhou H
- Subjects
- Animals, Female, Rats, Rats, Sprague-Dawley, Gene Expression Regulation physiology, Ovary metabolism, Physical Conditioning, Animal, Proteasome Endopeptidase Complex biosynthesis, Ubiquitin biosynthesis
- Abstract
The female reproductive system is highly sensitive to physiological stress. However, the mechanism(s) involved in dysfunction of the ovaries induced by high intensity exercise training remain unknown. In the present study, we established a rat model of high intensity exercise training, and investigated the morphological and functional changes in ovaries. Furthermore, we profiled the differential gene expression in the ovaries between high intensity exercise training rats and control rats by restriction fragment differential display PCR. Differentially expressed genes were validated by real-time PCR. The results showed that the weight and microstructure of the ovaries were significantly altered in the exercise training group rats. In addition, the levels of estradiol, progesterone, luteinizing hormone and follicle-stimulating hormone were significantly decreased in the exercise training group rats compared with the control group rats. Immunohistochemistry revealed weak expression of estradiol, estrogen receptor and progesterone receptor in ovarian tissues from the high intensity exercise training group compared with the control group. Furthermore, the gene expression profiles of the exercise training and control group rats were analyzed, and differentially expressed genes, such as those involved in the ubiquitin-proteasome system, were identified. Our results indicate that high intensity exercise training can suppress the cellular function of the ovary glands. The mechanism may involve a series of alterations in the expression of genes particularly associated with the ubiquitin-proteasome system.
- Published
- 2012
- Full Text
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43. Apoptotic effect of Vibrio vulnificus cytolysin on A549 human lung adenocarcinoma cells.
- Author
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Sun J, Zheng J, Wang G, Li Y, and Shen H
- Subjects
- Adenocarcinoma metabolism, Adenocarcinoma of Lung, Caspase 3 metabolism, Caspase 9 metabolism, Cell Line, Tumor, Cell Survival drug effects, DNA Fragmentation, Humans, L-Lactate Dehydrogenase metabolism, Lung Neoplasms metabolism, Perforin genetics, Perforin metabolism, Proto-Oncogene Proteins c-bcl-2 metabolism, Recombinant Proteins genetics, Recombinant Proteins metabolism, Recombinant Proteins toxicity, bcl-2-Associated X Protein metabolism, Antineoplastic Agents pharmacology, Apoptosis drug effects, Perforin pharmacology, Vibrio vulnificus metabolism
- Abstract
Vibrio vulnificus cytolysin (VVC) has a very strong cytotoxic effect on various types of mammalian cells. However, the inhibitory effect of VVC on the proliferation of human lung cancer cells has scarcely been reported. This study aimed to analyze the effects of recombinant VVC (rVVC) on the A549 human lung adenocarcinoma cell line and to investigate the underlying molecular mechanisms governing these effects. This study showed that rVVC inhibited the proliferation of A549 cells in a concentration- and time-dependent manner (as measured by the MTT assay). rVVC failed to induce the release of intracellular lactate dehydrogenase (LDH) from the target cells suggesting that osmotic lysis may not contribute to its cytolysin-induced cytotoxicity. Treatment of A549 cells with an IC50 (concentration of drug that inhibits cell growth by 50%) of rVVC resulted in morphological changes and blebbing typical of apoptosis. Annexin-V FITC analysis by FCM indicated that rVVC-induced apoptosis in A549 cells occurs in a dose-dependent manner. A DNA fragmentation assay was utilized to investigate the apoptosis induced by rVVC. The pro-apoptotic activity of rVVC was attributed to its ability to modulate, in a concerted manner, the expression of Bcl-2 and Bax proteins, which were down- and up-regulated, respectively. Caspase-9 and -3 were subsequently activated, however caspase-8 was not. These results prove that rVVC effectively induces programmed cell death and suggests that rVVC-induced apoptosis in the A549 cell line is mediated by the regulation of Bcl-2 protein expression and the activation of caspase-9 and -3.
- Published
- 2012
- Full Text
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44. Despotism and risk of infanticide influence grizzly bear den-site selection.
- Author
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Libal NS, Belant JL, Leopold BD, Wang G, and Owen PA
- Subjects
- Alaska, Animals, Area Under Curve, Female, Male, Risk, Social Dominance, Behavior, Animal, Predatory Behavior, Social Behavior, Ursidae physiology
- Abstract
Given documented social dominance and intraspecific predation in bear populations, the ideal despotic distribution model and sex hypothesis of sexual segregation predict adult female grizzly bears (Ursus arctos) will avoid areas occupied by adult males to reduce risk of infanticide. Under ideal despotic distribution, juveniles should similarly avoid adult males to reduce predation risk. Den-site selection and use is an important component of grizzly bear ecology and may be influenced by multiple factors, including risk from conspecifics. To test the role of predation risk and the sex hypothesis of sexual segregation, we compared adult female (n = 142), adult male (n = 36), and juvenile (n = 35) den locations in Denali National Park and Preserve, Alaska, USA. We measured elevation, aspect, slope, and dominant land cover for each den site, and used maximum entropy modeling to determine which variables best predicted den sites. We identified the global model as the best-fitting model for adult female (area under curve (AUC) = 0.926) and elevation as the best predictive variable for adult male (AUC = 0.880) den sites. The model containing land cover and elevation best-predicted juvenile (AUC = 0.841) den sites. Adult females spatially segregated from adult males, with dens characterized by higher elevations (mean= 1,412 m, SE = 52) and steeper slopes (mean = 21.9°, SE = 1.1) than adult male (elevation: mean = 1,209 m, SE = 76; slope: mean = 15.6°, SE = 1.9) den sites. Juveniles used a broad range of landscape attributes but did not avoid adult male denning areas. Observed spatial segregation by adult females supports the sex hypothesis of sexual segregation and we suggest is a mechanism to reduce risk of infanticide. Den site selection of adult males is likely related to distribution of food resources during spring.
- Published
- 2011
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45. Multiple paternities increase genetic diversity of offspring in Brandt's voles.
- Author
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Huo YJ, Wan XR, Wolff JO, Wang G, Thomas S, Iglay RB, Leopold BD, and Liu W
- Subjects
- Animals, DNA genetics, Female, Gene Frequency, Genotype, Male, Microsatellite Repeats, Pregnancy, Reverse Transcriptase Polymerase Chain Reaction, Social Behavior, Arvicolinae physiology, Genetic Variation physiology, Sexual Behavior, Animal physiology
- Abstract
Mating system and philopatry influence the genetic structure of a social group in mammals. Brandt's vole (Lasiopodomys brandtii) lives in social groups year-round and has male biased dispersal, which makes the vole a model system for studies of genetic consequences of mating system and philopatry. This study aimed to test the hypotheses that: (1) multiple paternity (MP) would exist in Brandt's voles, enhance offspring genetic diversity and reduce genetic relatedness between littermates; (2) promiscuity would occur in this species in that males and females mate with multiple partners; and (3) plural breeders of a social group would be genetically related because of philopatry of female juveniles in Brandt's voles. Paternity analysis indicated that MP occurred in 11 (46%) of 24 social groups examined and that promiscuity existed in this species. Multiple paternity litters had twice the offspring genetic diversity and half the average within-litter genetic relatedness of single paternity litters. We also found plural breeding females in six social groups. Average pairwise genetic relatedness of plural breeders ranged from 0.41 to 0.72 in four social groups, suggesting first-order kinship. Future studies need to investigate effects of reproductive skew and MP on population genetic structure of Brandt's voles., (Copyright (c) 2010 Elsevier B.V. All rights reserved.)
- Published
- 2010
- Full Text
- View/download PDF
46. Dry weather induces outbreaks of human West Nile virus infections.
- Author
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Wang G, Minnis RB, Belant JL, and Wax CL
- Subjects
- Humans, Mississippi epidemiology, Disease Outbreaks, Rain, West Nile Fever epidemiology
- Abstract
Background: Since its first occurrence in the New York City area during 1999, West Nile virus (WNV) has spread rapidly across North America and has become a major public health concern in North America. By 2002, WNV was reported in 40 states and the District of Columbia with 4,156 human and 14,539 equine cases of infection. Mississippi had the highest human incidence rate of WNV during the 2002 epidemic in the United States. Epidemics of WNV can impose enormous impacts on local economies. Therefore, it is advantageous to predict human WNV risks for cost-effective controls of the disease and optimal allocations of limited resources. Understanding relationships between precipitation and WNV transmission is crucial for predicting the risk of the human WNV disease outbreaks under predicted global climate change scenarios., Methods: We analyzed data on the human WNV incidences in the 82 counties of Mississippi in 2002, using standard morbidity ratio (SMR) and Bayesian hierarchical models, to determine relationships between precipitation and human WNV risks. We also entertained spatial autocorrelations of human WNV risks with conditional autocorrelative (CAR) models, implemented in WinBUGS 1.4.3., Results: We observed an inverse relationship between county-level human WNV incidence risk and total annual rainfall during the previous year. Parameters representing spatial heterogeneity in the risk of human exposure to WNV improved model fit. Annual precipitation of the previous year was a predictor of spatial variation of WNV risk., Conclusions: Our results have broad implications for risk assessment of WNV and forecasting WNV outbreaks. Assessing risk of vector-born infectious diseases will require understanding of complex ecological relationships. Based on the climatologically characteristic drought occurrence in the past and on climate model predictions for climate change and potentially greater drought occurrence in the future, we suggest that the frequency and relative risk of WNV outbreaks could increase.
- Published
- 2010
- Full Text
- View/download PDF
47. Spatial synchrony propagates through a forest food web via consumer-resource interactions.
- Author
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Haynes KJ, Liebhold AM, Fearer TM, Wang G, Norman GW, and Johnson DM
- Subjects
- Animals, Models, Biological, Moths physiology, New England, Peromyscus physiology, Population Dynamics, Quercus, Seeds, Food Chain, Trees
- Abstract
In many study systems, populations fluctuate synchronously across large regions. Several mechanisms have been advanced to explain this, but their importance in nature is often uncertain. Theoretical studies suggest that spatial synchrony initiated in one species through Moran effects may propagate among trophically linked species, but evidence for this in nature is lacking. By applying the nonparametric spatial correlation function to time series data, we discover that densities of the gypsy moth, the moth's chief predator (the white-footed mouse), and the mouse's winter food source (red oak acorns) fluctuate synchronously over similar distances (approximately1000 km) and with similar levels of synchrony. In addition, we investigate the importance of consumer-resource interactions in propagating synchrony among species using an empirically informed simulation model of interactions between acorns, the white-footed mouse, the gypsy moth, and a viral pathogen of the gypsy moth. Our results reveal that regional stochasticity acting directly on populations of the mouse, moth, or pathogen likely has little effect on levels of the synchrony displayed by these species. In contrast, synchrony in mast seeding can propagate across trophic levels, thus explaining observed levels of synchrony in both white-footed mouse and gypsy moth populations. This work suggests that the transfer of synchrony among trophically linked species may be a major factor causing interspecific synchrony.
- Published
- 2009
- Full Text
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48. Electroosmotic flow in nanotubes with high surface charge densities.
- Author
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Chen Y, Ni Z, Wang G, Xu D, and Li D
- Abstract
The ion distribution and electroosmotic flow of sodium chlorine solutions confined in cylindrical nanotubes with high surface charge densities are studied with molecular dynamics (MD). To obtain a more practical physical model for electroosmotic driven flow in a nanoscale tube, the MD simulation process consists of two steps. The first step is used to equilibrate the system and to obtain a more realistic ion distribution in the solution under different surface charge densities. Then, an external electric field is acted to drive the liquids. The simulation results indicate that with the increase of the surface charge density, both the thickness of the electric double layer and the peak height of the counterion density increase. However, the phenomenon of charge inversion does not occur even as the surface charge density increases to -0.34 C/m2, which is rather difficult to reach for real materials in practical situations. This simulation result confirms the recent experimental observation that monovalent ions of sufficiently high concentrations can reduce or even cancel the charge inversion occurred in the case of multivalent ions [F. H. J. van der Heyden et al. Phys. Rev. Lett. 2006, 96, 224502].
- Published
- 2008
- Full Text
- View/download PDF
49. Composite forces shape population dynamics of copepod crustaceans.
- Author
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Twombly S, Wang G, and Hobbs NT
- Subjects
- Animals, Likelihood Functions, Population Dynamics, Venezuela, Copepoda physiology, Demography, Ecosystem, Models, Theoretical, Population Density, Zooplankton physiology
- Abstract
Understanding the processes that control species abundance and distribution is a major challenge in ecology, yet for a large number of potentially important organisms, we know little about the biotic and abiotic factors that influence population size. One group of aquatic organisms that defies traditional demographic analyses is the Crustacea, particularly those with complex life cycles. We used likelihood techniques and information theoretics to evaluate a suite of models representing alternative hypotheses on factors controlling the abundance of two copepod crustaceans in a small, tropical floodplain lake. Quantitative zooplankton samples were collected at three stations in a Venezuelan floodplain lake from June through December 1984; the average sampling interval was two days. We constructed a series of models with stage structure that incorporated six biotic and abiotic covariates in various combinations to account for temporal changes in abundance of these target species and in their population growth rates. Our analysis produced several novel insights into copepod population dynamics. We found that multiple forces affected the abundance of particular stages, that these factors differed between species as well as among stages within each species, and that biotic processes had the largest effects on copepod population dynamics. Density dependence had a large effect on the survival of Oithona amazonica copepodites and on population growth rate of Diaptomus negrensis.
- Published
- 2007
- Full Text
- View/download PDF
50. Projected ecosystem impact of the Prairie Heating and CO2 Enrichment experiment.
- Author
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Parton WJ, Morgan JA, Wang G, and Del Grosso S
- Subjects
- Models, Biological, Poaceae physiology, Soil analysis, Temperature, Trees physiology, United States, Climate, Ecosystem, Plant Physiological Phenomena, Water
- Abstract
The Prairie Heating and CO2 Enrichment (PHACE) experiment has been initiated at a site in southern Wyoming (USA) to simulate the impact of warming and elevated atmospheric CO2 on ecosystem dynamics for semiarid grassland ecosystems. The DAYCENT ecosystem model was parametrized to simulate the impact of elevated CO2 at the open-top chamber (OTC) experiment in north-eastern Colorado (1996-2001), and was also used to simulate the projected ecosystem impact of the PHACE experiments during the next 10 yr. Model results suggest that soil water content, plant production, soil respiration, and nutrient mineralization will increase for the high-CO2 treatment. Soil water content will decrease for all years, while nitrogen mineralization, soil respiration, and plant production will both decrease and increase under warming depending on yearly differences in water stress. Net primary production (NPP) will be greatest under combined warming and elevated CO2 during wet years. Model results are consistent with empirical field data suggesting that water and nitrogen will be critical drivers of the semiarid grassland response to global change.
- Published
- 2007
- Full Text
- View/download PDF
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