Within the context of climate change, there is a pressing need to better understand the ecological implications of changes in the frequency and intensity of climate extremes. Along subtropical ...coasts, less frequent and warmer freeze events are expected to permit freeze-sensitive mangrove forests to expand poleward and displace freeze-tolerant salt marshes. Here, our aim was to better understand the drivers of poleward mangrove migration by quantifying spatiotemporal patterns in mangrove range expansion and contraction across land-ocean temperature gradients. Our work was conducted in a freeze-sensitive mangrove-marsh transition zone that spans a land-ocean temperature gradient in one of the world's most wetland-rich regions (Mississippi River Deltaic Plain; Louisiana, USA). We used historical air temperature data (1893–2014), alternative future climate scenarios, and coastal wetland coverage data (1978–2011) to investigate spatiotemporal fluctuations and climate-wetland linkages. Our analyses indicate that changes in mangrove coverage have been controlled primarily by extreme freeze events (i.e., air temperatures below a threshold zone of −6.3 to −7.6°C). We expect that in the past 121 yr, mangrove range expansion and contraction has occurred across land-ocean temperature gradients. Mangrove resistance, resilience, and dominance were all highest in areas closer to the ocean where temperature extremes were buffered by large expanses of water and saturated soil. Under climate change, these areas will likely serve as local hotspots for mangrove dispersal, growth, range expansion, and displacement of salt marsh. Collectively, our results show that the frequency and intensity of freeze events across land-ocean temperature gradients greatly influences spatiotemporal patterns of range expansion and contraction of freeze-sensitive mangroves. We expect that, along subtropical coasts, similar processes govern the distribution and abundance of other freeze-sensitive organisms. In broad terms, our findings can be used to better understand and anticipate the ecological effects of changing winter climate extremes, especially within the transition zone between tropical and temperate climates.
Tumor cells exhibit an altered metabolism characterized by elevated aerobic glycolysis and lactate secretion which is supported by an increase in glucose transport and consumption. We hypothesized ...that reducing or eliminating the expression of the most prominently expressed glucose transporter(s) would decrease the amount of glucose available to breast cancer cells thereby decreasing their metabolic capacity and proliferative potential.Of the 12 GLUT family glucose transporters expressed in mice, GLUT1 was the most abundantly expressed at the RNA level in the mouse mammary tumors from MMTV-c-ErbB2 mice and cell lines examined. Reducing GLUT1 expression in mouse mammary tumor cell lines using shRNA or Cre/Lox technology reduced glucose transport, glucose consumption, lactate secretion and lipid synthesis in vitro without altering the concentration of ATP, as well as reduced growth on plastic and in soft agar. The growth of tumor cells with reduced GLUT1 expression was impaired when transplanted into the mammary fat pad of athymic nude mice in vivo. Overexpression of GLUT1 in a cell line with low levels of endogenous GLUT1 increased glucose transport in vitro and enhanced growth in nude mice in vivo as compared to the control cells with very low levels of GLUT1.These studies demonstrate that GLUT1 is the major glucose transporter in mouse mammary carcinoma models overexpressing ErbB2 or PyVMT and that modulation of the level of GLUT1 has an effect upon the growth of mouse mammary tumor cell lines in vivo.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Tetrahymena thermophila is a ciliate model organism whose study has led to important discoveries and insights into both conserved and divergent biological processes. In this review, we describe the ...tools for the use of Tetrahymena as a model eukaryote, including an overview of its life cycle, orientation to its evolutionary roots, and methodological approaches to forward and reverse genetics. Recent genomic tools have expanded Tetrahymena's utility as a genetic model system. With the unique advantages that Tetrahymena provide, we argue that it will continue to be a model organism of choice.
Prisons have long been scrutinized for their destructive properties inside and outside of their walls, yet most of this work has focused on incarcerated men and those in the resource-deficient ...communities that house them. In these studies, mostly focused on the economic losses that families face by losing their primary breadwinners and the spillover of prison politics into these communities, women are largely ignored. As prisons are placed in divested communities, the existing social ills that draw them become exacerbated. This study examines how Latinas are rendered as carceral collateral by the passive and active violence rampant across California carceral communities. Using interviews/critical narratives of seventeen formerly incarcerated Latinas, I examined their multifaceted experiences of neglect and abuse, and their subsequent paths to criminalization. The findings demonstrate that the social ecology of the carceral community renders Latinas hypervulnerable to interpersonal, familial, and institutional neglect and abuse, which coerce these women to cope with their victimization in ways that are criminalized by the state and rejected by traditional sources of support. Furthermore, Latinas in carceral communities exist in what can be construed as a “perfect storm” of social problems wherein neoliberal constructions of worth collude with Latinx cultural practices to reinforce and perpetuate the devaluation of Latinas. This gives insight as to how decriminalization efforts may be better posed toward challenging the existing material and ideological roots of inequality embedded in both institutional and cultural constructs.
The forsterite zone of the Ubehebe Peak contact aureole, Death Valley, USA consists of an outer zone of tabular/jack-straw olivine and an inner zone of subequant polyhedral olivine. Subequant ...polyhedral forsterite crystals close to the intrusion are small and tabular forsterite crystals farther away are larger. To investigate the formation of the two morphologies, forsterite growth experiments were conducted in cold seal pressure vessels in the CaO-MgO-SiO
2
-CO
2
-H
2
O system. Forsterite precipitation follows a disequilibrium reaction pathway made of three reactions: 1 tabular forsterite growth from quartz and dolomite, 2 forsterite growth from tremolite dissolution, and 3 subequant polyhedral forsterite growth from tabular forsterite dissolution. Initially, quartz reacts with dolomite to simultaneously form twinned tabular forsterite and tremolite. As quartz reacts away, forsterite precipitation continues at a slower rate through tremolite dissolution. A second generation of forsterite then precipitates on top of some tabular forsterite but has different habit and tracht. Once all the tremolite reacts away, subequant polyhedral forsterite precipitation continues at an even slower rate through dissolution of tabular forsterite. The tabular morphology of jack-straw olivine is a consequence of twin-mediated unidirectional growth; the abundance of twins being due to rapid nucleation and growth at initially high reaction affinities. Twin junctions are preferential nucleation centers for steps, so faceted growth is enhanced on {100}. This phenomenon is the twin plane re-entrant effect. Subequant polyhedral forsterite in the Ubehebe Peak inner contact aureole recrystallized and ripened from tabular forsterite. In the outer contact aureole, conditions were not conducive to recrystallization and ripening so well-developed tabular forsterite persists.
Basal bodies (BBs) are conserved eukaryotic structures that organize cilia. They are comprised of nine, cylindrically arranged, triplet microtubules (TMTs) connected to each other by inter-TMT ...linkages which stabilize the structure. Poc1 is a conserved protein important for BB structural integrity in the face of ciliary forces transmitted to BBs. To understand how Poc1 confers BB stability, we identified the precise position of Poc1 in the Tetrahymena BB and the effect of Poc1 loss on BB structure. Poc1 binds at the TMT inner junctions, stabilizing TMTs directly. From this location, Poc1 also stabilizes inter-TMT linkages throughout the BB, including the cartwheel pinhead and the inner scaffold. The full localization of the inner scaffold protein Fam161A requires Poc1. As ciliary forces are increased, Fam161A is reduced, indicative of a force-dependent molecular remodeling of the inner scaffold. Thus, while not essential for BB assembly, Poc1 promotes BB interconnections that establish an architecture competent to resist ciliary forces.
When LCA practitioners perform LCAs, the interpretation of the results can be difficult without a reference point to benchmark the results. Hence, normalization factors are important for relating ...results to a common reference. The main purpose of this paper was to update the normalization factors for the US and US-Canadian regions. The normalization factors were used for highlighting the most contributing substances, thereby enabling practitioners to put more focus on important substances, when compiling the inventory, as well as providing them with normalization factors reflecting the actual situation. Normalization factors were calculated using characterization factors from the TRACI 2.1 LCIA model. The inventory was based on US databases on emissions of substances. The Canadian inventory was based on a previous inventory with 2005 as reference, in this inventory the most significant substances were updated to 2008 data. The results showed that impact categories were generally dominated by a small number of substances. The contribution analysis showed that the reporting of substance classes was highly significant for the environmental impacts, although in reality, these substances are nonspecific in composition, so the characterization factors which were selected to represent these categories may be significantly different from the actual identity of these aggregates. Furthermore the contribution highlighted the issue of carefully examining the effects of metals, even though the toxicity based categories have only interim characterization factors calculated with USEtox. A need for improved understanding of the wide range of uncertainties incorporated into studies with reported substance classes was indentified. This was especially important since aggregated substance classes are often used in LCA modeling when information on the particular substance is missing. Given the dominance of metals to the human and ecotoxicity categories, it is imperative to refine the CFs within USEtox. Some of the results within this paper indicate that soil emissions of metals are significantly higher than we expect in actuality.
ABSTRACTWe aimed to determine whether tissue transglutaminase (tTG) autoantibody positivity was associated with dietitian-assessed adherence to a gluten-free diet in pediatric patients with celiac ...disease and identify areas where adherence falters. We reviewed the records of children with celiac disease who had a standardized evaluation of adherence by a registered dietitian. A negative tTG value was not associated with good adherence (P = NS). Adherent and nonadherent children differed with respect to purposeful and accidental gluten exposure (P < 0.0001), knowledge (P = 0.003), cross-contact (P = 0.003), potential exposure via medications and cosmetics (P = 0.004), and potential exposure while at restaurants (P < 0.0001), but not with respect to potential exposure at school (P = NS). Based on our findings, we suggest that negative tTG levels are not necessarily indicative of good adherence to a gluten-free diet in pediatric patients with celiac disease. A separate assessment of adherence is needed focusing on knowledge, behavior while dining out, and intent to adhere.
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•Phytotoxicity of AgNPs on plants of Vicia faba were tested.•Vicia faba leaves were exposed to different AgNPs dimensions (20, 51, and 73 nm).•AgNPs were able to affect the ...photosynthetic activity of plants.•AgNPs caused alterations on PSII activity, stomatal conductance, and CO2 assimilation.•Phytotoxic effects increased with decreasing AgNPs diameter.
Nanotechnology is an emerging field in science and engineering, which presents significant impacts on the economy, society and the environment. The nanomaterials’ (NMs) production, use, and disposal is inevitably leading to their release into the environment where there are uncertainties about its fate, behaviour, and toxicity. Recent works have demonstrated that NMs can penetrate, translocate, and accumulate in plants. However, studies about the effects of the NMs on plants are still limited because most investigations are carried out in the initial stage of plant development. The present study aimed to evaluate and characterize the photochemical efficiency of photosystem II (PSII) of broad bean (Vicia faba) leaves when subjected to silver nanoparticles (AgNPs) with diameters of 20, 51, and 73 nm as well as to micrometer-size Ag particles (AgBulk). The AgNPs were characterized by transmission electron microscopy and dynamic light scattering. The analyses were performed by injecting the leaves with 100 mg L−1 aqueous solution of Ag and measuring the chlorophyll fluorescence imaging, gas exchange, thermal imaging, and reactive oxygen species (ROS) production. In addition, silver ion (Ag+) release from Ag particles was determined by dialysis. The results revealed that AgNPs induce a decrease in the photochemical efficiency of photosystem II (PSII) and an increase in the non-photochemical quenching. The data also revealed that AgNPs affected the stomatal conductance (gs) and CO2 assimilation. Further, AgNPs induced an overproduction of ROS in Vicia faba leaves. Finally, all observed effects were particle diameter-dependent, increasing with the reduction of AgNPs diameter and revealing that AgBulk caused only a small or no changes on plants. In summary, the results point out that AgNPs may negatively affect the photosynthesis process when accumulated in the leaves, and that the NPs themselves were mainly responsible since negligible Ag+ release was detected.
Summary
The importance of increase in the scarcity of resources can be assessed using different approaches. Here, we propose a method that is based on the amount of extra ore mined to assess the ...importance of the extraction of resources. The surplus ore potential (SOP) indicator quantifies the extra amount of ore mined per additional unit of resource extracted by applying log‐logistic cumulative grade‐tonnage relationships and reserve estimates. We derived SOPs for 18 resources (17 metals including uranium and phosphorus) with 5 orders of magnitude difference (between 4.1 × 10−1 kilograms kg of extra ore per kg of manganese extracted and 5.5 × 104 kg of extra ore per kg of gold extracted). The sensitivity of the SOP values to the choice of reserve estimates (reserves vs. ultimate recoverable resource) are within a factor of 3 of each other. Combining the SOP values with the 2012 global extraction rates of these 18 resources resulted in a 236 to 372 kgore/capita surplus ore extracted. Iron, phosphorus, copper, gold, and aluminium were the largest contributors. The large variation in SOP values we observed between resources emphasizes the potential relevance of including resource‐specific SOP values to assess the contribution to resource scarcity by specific products and technologies.
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