•Road dust can be a source of nutrients for peatlands, especially phosphorus.•The effects of road dust vary depending on its deposition level and chemical composition.•Mosses are more responsive to ...road dust deposition than shrubs.
Dust deposition can fertilize nutrient-limited peatlands and affect their plant assemblages and ecosystem functions, but the effects of local road dust on peatlands have seldom been studied. Here, we investigate the responses of vegetation composition and surface chemistry (vegetation, surface peat, and groundwater chemistry) at three ombrotrophic peatlands: Rivière-au-Tonnerre (RT), Chemin de l'Anse-de-la-Grande-Pointe (GP), and Kegaska (KEG) in eastern Québec, Canada, to varying levels of road dust deposition with differential chemical composition. At each site, a transect aligned with the dominant wind direction, starting at and perpendicular to the roadside, was sampled at increasing intervals up to 250 m away from the gravel (unpaved) road. We find that the ash content of surface peat is highest closest to the roads at all three sites and decreases exponentially with increasing distance up to 200 m away from the roads. At KEG, with the highest amount of, and the most phosphorus (P) rich, road dust deposition, the ash content is highest among the three sites, decreasing most rapidly with distance away from the road. The stoichiometric mass ratios of carbon (C), nitrogen (N) and P, i.e., C:N, C:P, and N:P, in foliar tissues and surface peat increase significantly with distance away from the road at KEG, and mosses are found to be more responsive in terms of foliar chemistry than shrubs to the road dust deposition. A higher concentration of total dissolved phosphorus at KEG is found closer to the road. At GP, having a moderate amount of road dust deposition, significant increases in C:N, C:P, and N:P ratios with distance are found only in surface peat but not in foliar tissues. Due to the presence of carbonate minerals in the road dust of GP, the calcium (Ca) concentration and pH value of groundwater closer to the road are higher, leading to an obvious loss of vegetation coverage, especially mosses, and a consequent increase in NO3− leaching. In contrast, at RT, having the lowest amount of road dust deposition, only a few clear variation patterns in surface chemistry are found along the sampling transect. Overall, our results suggest that dust from gravel roads can be an important localized source of nutrients for adjacent peatlands and influence their vegetation composition and surface chemistry, depending on the amount of road dust and its chemical composition, especially its contents in Ca and P.
Academic mobility for field work, research dissemination and global outreach is increasingly recognized as an important contributor to the overall environmental footprint of research institutions. ...Student mobility, while less studied, also contributes to universities' environmental footprint. Université de Montréal (UdeM) is the largest university in Montréal, Canada. It has a research budget of 450M$, employs 1426 full-time professors, and has a total student population of 33 125 undergraduate and 12 505 graduate students. To assess the footprint of academic mobility at UdeM, we surveyed the research community (n = 703; including professors, research professionals and graduate students) about their travel habits. We also measured the contribution from travel undertaken by sports teams and international students as well as students engaged in study abroad and internships programs using data provided by the university. While the average distance travelled for work and research purposes by the UdeM community is around 8525 km/person, professors travel more than 33 000 km/person per year. We also estimated that the 5785 international students or students enroled in study abroad programs travel annually around 12 600 km/person. UdeM's per capita annual travel-related C and N footprints vary, with international students generating for example 3.85 T CO2 and 0.53 kg N while professors generate 10.76 T CO2 and 2.19 kg N. Air travel emissions are the main contributors to these footprints. We provide insights into the distribution of travel-related environmental footprint within the university, the main reasons for travelling, the most frequent destinations, and the factors preventing researchers from reducing their travel-related environmental impact.
Tropical peatlands cover an estimated 440 000 km²(~10% of global peatland area) and are significant in the global carbon cycle by storing about 40–90 Gt C in peat. Over the past several decades, ...tropical peatlands have experienced high rates of deforestation and conversion, which is often associated with lowering the water table and peat burning, releasing large amounts of carbon stored in peat to the atmosphere. We present the first model of long‐term carbon accumulation in tropical peatlands by modifying the Holocene Peat Model (HPM), which has been successfully applied to northern temperate peatlands. Tropical HPM (HPMTrop) is a one‐dimensional, nonlinear, dynamic model with a monthly time step that simulates peat mass remaining in annual peat cohorts over millennia as a balance between monthly vegetation inputs (litter) and monthly decomposition. Key model parameters were based on published data on vegetation characteristics, including net primary production partitioned into leaves, wood, and roots; and initial litter decomposition rates. HPMTrop outputs are generally consistent with field observations from Indonesia. Simulated long‐term carbon accumulation rates for 11 000‐year‐old inland, and 5 000‐year‐old coastal peatlands were about 0.3 and 0.59 Mg C ha⁻¹ yr⁻¹, and the resulting peat carbon stocks at the end of the 11 000‐year and 5 000‐year simulations were 3300 and 2900 Mg C ha⁻¹, respectively. The simulated carbon loss caused by coastal peat swamp forest conversion into oil palm plantation with periodic burning was 1400 Mg C ha⁻¹over 100 years, which is equivalent to ~2900 years of C accumulation in a hectare of coastal peatlands.
Osteosarcoma is the main malignant primary bone tumor in children and adolescents for whom the prognosis remains poor, especially when metastasis is present at diagnosis. Because transforming growth ...factor-β (TGFβ) has been shown to promote metastasis in many solid tumors, we investigated the effect of the natural TGFβ/Smad signaling inhibitor Smad7 and the TβRI inhibitor SD-208 on osteosarcoma behavior.
By using a mouse model of osteosarcoma induced by paratibial injection of cells, we assessed the impact of Smad7 overexpression or SD-208 on tumor growth, tumor microenvironment, bone remodeling, and metastasis development.
First, we demonstrated that TGFβ levels are higher in serum samples from patients with osteosarcoma compared with healthy volunteers and that TGFβ/Smad3 signaling pathway is activated in clinical samples. Second, we showed that Smad7 slows the growth of the primary tumor and increases mice survival. We furthermore demonstrated that Smad7 expression does not affect in vitro osteosarcoma cell proliferation but affects the microarchitectural parameters of bone. In addition, Smad7-osteosarcoma bone tumors expressed lower levels of osteolytic factors such as RANKL, suggesting that Smad7 overexpression affects the "vicious cycle" established between tumor cells and bone cells by its ability to decrease osteoclast activity. Finally, we showed that Smad7 overexpression in osteosarcoma cells and the treatment of mice with SD208 inhibit the development of lung metastasis.
Taken together, these results demonstrate that the inhibition of the TGFβ/Smad signaling pathway may be a promising therapeutic strategy against tumor progression of osteosarcoma, specifically against the development of lung metastasis.
Abstract
High-latitude peatlands are changing rapidly in response to climate change, including permafrost thaw. Here, we reconstruct hydrological conditions since the seventeenth century using ...testate amoeba data from 103 high-latitude peat archives. We show that 54% of the peatlands have been drying and 32% have been wetting over this period, illustrating the complex ecohydrological dynamics of high latitude peatlands and their highly uncertain responses to a warming climate.
Peatlands occupy a relatively small fraction of the Earth's land area, but they are a globally important carbon store because of their high carbon density. Undisturbed peatlands are currently a weak ...carbon sink (~0.1 Pg C y−1), a moderate source of methane (CH4; ~0.03 Pg CH4y−1), and a very weak source of nitrous oxide (N2O; ~0.00002 Pg N2O–N y−1). Anthropogenic disturbance, primarily agriculture and forestry drainage (10%–20% of global peatlands), results in net CO2emissions, reduced CH4emissions, and increased N2O emissions. This likely changes the global peatland greenhouse gas balance to a C source (~0.1 Pg C y−1), a 10% smaller CH4source, and a larger (but still small) N2O source (~0.0004 Pg N2O–N y−1). There is no strong evidence that peatlands significantly contributed to 20th century changes in the atmospheric burden of CO2, CH4, or N2O; will this picture change in the 21st century? A review of experimental and observational studies of peatland dynamics indicates that the main global change impacts on peatlands that may have significant climate impacts are (1) drainage, especially in the tropics; (2) widespread permafrost thaw; and (3) increased fire intensity and frequency as a result of drier climatic conditions and (or) drainage. Quantitative estimates of global change impacts are limited by the sparse field data (particularly in the tropics), the large variability present in existing data, uncertainties in the future trajectory of peatland use, interactive effects of individual impacts, and the unprecedented rates of climate change expected in the 21st century.
Abstract
Swamps are a highly significant wetland type in North America both in terms of areal extent and their role in terrestrial carbon cycling. These wetlands, characterized by woody vegetation ...cover, encompass a diverse suite of ecosystems, including broad-leaved, needle-leaved, mixedwood or shrub/thicket swamps. Uncertainties in the role of swamps in carbon uptake and release continue to be substantial due to insufficient data on variabilities in carbon densities across diverse swamp types and relatively few flux measurements from swamp sites. Robust measurements of rates of vertical accretion of swamp soils and the associated long-term rates of carbon accumulation, alongside measurements of carbon losses from swamps, are needed for emerging frameworks for carbon accounting, and for assessments of the impacts of climate warming and land use change on this important wetland type. Based on data compilation, we present here a comparative analysis from a series of North American swamp sites on carbon dioxide, methane and dissolved organic carbon fluxes, aboveground biomass, net primary productivity (NPP), and soil carbon properties including bulk densities, organic carbon contents, peat depths, rates of vertical accretion, and rates of long-term carbon accumulation. We compare these properties for four major swamp types: needle-leaved, broad-leaved, mixedwood and shrub/thicket swamps. We show differences in carbon fluxes, biomass and NPP across the four types, with broad-leaved swamps having the largest CH
4
flux, highest soil bulk densities, thinnest peat depths and lowest soil organic matter contents, whereas needle-leaved swamps have the smallest CH
4
flux, highest aboveground biomass and highest NPP. We show high soil carbon stocks (kg C m
−2
) in all types of swamps, even those where organic deposits were too shallow to meet the definition of peat. However, we note there is a significant lack of studies focused on swamp carbon dynamics despite their abundance across Canada and the United States.
Abstract
Most lncRNAs display species-specific expression patterns suggesting that animal models of cancer may only incompletely recapitulate the regulatory crosstalk between lncRNAs and oncogenic ...pathways in humans. Among these pathways, Sonic Hedgehog (SHH) signaling is aberrantly activated in several human cancer entities. We unravel that aberrant expression of the primate-specific lncRNA
HedgeHog Interacting Protein-AntiSense 1
(
HHIP-AS1
) is a hallmark of SHH-driven tumors including medulloblastoma and atypical teratoid/rhabdoid tumors.
HHIP-AS1
is actively transcribed from a bidirectional promoter shared with SHH regulator
HHIP
. Knockdown of
HHIP-AS1
induces mitotic spindle deregulation impairing tumorigenicity in vitro and in vivo. Mechanistically,
HHIP-AS1
binds directly to the mRNA of
cytoplasmic dynein 1 intermediate chain 2
(
DYNC1I2
) and attenuates its degradation by hsa-miR-425-5p. We uncover that neither
HHIP-AS1
nor the corresponding regulatory element in
DYNC1I2
are evolutionary conserved in mice. Taken together, we discover an lncRNA-mediated mechanism that enables the pro-mitotic effects of SHH pathway activation in human tumors.
Osteosarcomas are the most prevalent malignant primary bone tumors in children. Despite intensive efforts to improve both chemotherapeutics and surgical management, 40% of all osteosarcoma patients ...succumb to the disease. Specifically, the clinical outcome for metastatic osteosarcoma remains poor; less than 30% of patients who present metastases will survive five years after initial diagnosis. Treating metastatic osteosarcoma thus remains a challenge. One of the main characteristics of osteosarcomas is their ability to deregulate bone remodelling. The invasion of bone tissue by tumor cells indeed affects the balance between bone resorption and bone formation. This deregulation induces the release of cytokines or growth factors initially trapped in the bone matrix, such as transforming growth factor-β (TGF-β), which in turn promote tumor progression. Over the past years, there has been considerable interest in the TGF-β pathway within the cancer research community. This review discusses the involvement of the TGF-β signalling pathway in osteosarcoma development and in their metastatic progression.
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