Nutrient Regulation Research Articles

Potassium and Magnesium in American Ginseng Roots as Key Factors in Monitoring Soil Quality, Yield, and Quality: Screening, Prediction, and Validation

Understanding the key roles of nutrient elements in soil–plant systems are essential for herbal medicine production and sustainable development. However, the ecological relationships between soil quality and nutrient elements, yield, saponins, or other active compounds in American ginseng remain unclear. In this study, 20 soil indicators, 10 root nutrient indicators, 9 quality indicators, and yields were investigated. The minimum dataset was constructed by principal component analysis, key factors were screened by correlation analysis and PLS-PM analysis, and the prediction model was constructed using linear fitting and tested by a validation test. The minimum dataset, constructed based on principal component analysis, comprised five indicators: SOM, TP, AK, AMg, and ACa. Correlation analysis, PLS-PM analysis, and linear fitting showed that K and Mg were the key factors relating soil quality to the yield and quality of American ginseng and that when AMg was 0.21 g/kg and AK was 0.30 g/kg, soil organic matter was 27%, total phosphorus was 1.19 g/kg in soil, K content in roots was 15.63 g/kg, Mg content was 1.91 g/kg, and the K/Mg of 8.85 could balance American ginseng yield and quality. In predicting and validating the model, predicting the DW, total ginsenoside, Rb1, Rb2, Rc, and Rd of American ginseng using K/Mg were reliable. This study provides a scientific basis for nutrient regulation, selecting planting sites, assessing soil quality, and predicting and evaluating American ginseng quality.

Abstract 4322: Inhibition of ULK and KRASG12C control tumor growth in preclinical models of lung cancer

Abstract Approximately 30% of lung cancers are driven by mutationally activated KRAS. The recent FDA approval of sotorasib, a direct pharmacological inhibitor of KRASG12C, marks a critical milestone in the treatment of this important subset of lung cancer. However, a major obstacle in treating lung cancer is resistance to current therapeutic treatments. In response to cellular stresses such as RAS pathway-targeted therapeutics, RAS-mutated cancer cells have been demonstrated to increase autophagy, an intracellular recycling pathway. However, the mechanism(s) underlying treatment-induced autophagy is not well understood. Here, we demonstrate that KRASG12C-driven lung cancer cells increase autophagy in response to treatment with sotorasib. Currently, the only therapeutics in clinical use to inhibit autophagy are lysosomal inhibitors (hydroxy)chloroquine. High concentrations of these compounds are needed to achieve modest inhibition of autophagy, suggesting that the potency of these compounds may limit clinical responses. ULK kinases are serine/threonine kinases that are necessary for the initiation of autophagy. DCC-3116 is a potent inhibitor of the ULK1/2 protein kinases, master regulators of autophagy. Treatment with sotorasib and DCC-3116 led to superior anti-tumor effects in preclinical models of lung cancer. Additionally, about 30% of lung cancer patients with KRAS mutations also have deletions or inactivating mutations in LKB1, a protein involved in the regulation of nutrient sensing and autophagy. In other KRAS-driven cancers, the LKB1-AMPK-ULK1 signaling axis is a proposed mechanism as to how autophagic flux increases following KRAS pathway inhibition. However, our preliminary data demonstrates that LKB1 is dispensable for sotorasib-induced autophagy, suggesting the mechanism(s) of autophagy induction in KRASG12C-driven lung cancer may be different from those detected in other KRAS mutated cancers. Consequently, we have generated genetically engineered mouse models (GEMMs) of KRASG12C-driven lung cancer in which LKB1 is silenced to further investigate the role of LKB1 in the autophagy response of KRASG12C-driven lung cancers to pathway-targeted blockade of oncogenic KRAS signaling. We have treated KRASG12C-driven GEMMs with sotorasib and/or DCC-3116 to test the sensitivity of lung tumors to these treatment options. Citation Format: Phaedra Ghazi, Kayla O'Toole, Sanjana Boggaram, Michael Scherzer, Madhumita Bogdan, Bryan Smith, Dan Flynn, Conan Kinsey, Martin McMahon. Inhibition of ULK and KRASG12C control tumor growth in preclinical models of lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4322.

Leaf nutrient traits of planted forests demonstrate a heightened sensitivity to environmental changes compared to natural forests.

Leaf nutrient content (nitrogen, phosphorus) and their stoichiometric ratio (N/P) as key functional traits can reflect plant survival strategies and predict ecosystem productivity responses to environmental changes. Previous research on leaf nutrient traits has primarily focused on the species level with limited spatial scale, making it challenging to quantify the variability and influencing factors of forest leaf nutrient traits on a macro scale. This study, based on field surveys and literature collected from 2005 to 2020 on 384 planted forests and 541 natural forests in China, investigates the differences in leaf nutrient traits between forest types (planted forests, natural forests) and their driving factors. Results show that leaf nutrient traits (leaf nitrogen content (LN), leaf phosphorus content (LP), and leaf N/P ratio) of planted forests are significantly higher than those of natural forests (P< 0.05). The impact of climatic and soil factors on the variability of leaf nutrient traits in planted forests is greater than that in natural forests. With increasing forest age, natural forests significantly increase in leaf nitrogen and phosphorus content, with a significant decrease in N/P ratio (P< 0.05). Climatic factors are key environmental factors dominating the spatial variability of leaf nutrient traits. They not only directly affect leaf nutrient traits of planted and natural forest communities but also indirectly through regulation of soil nutrients and stand factors, with their direct effects being more significant than their indirect effects.

The chemical stoichiometry characteristics of plant-soil carbon and nitrogen in subtropical Pinus massoniana natural forests

Ecological stoichiometry is essential for understanding changes in ecosystem structure and nutrient cycling in forest ecosystems. However, the stoichiometric characteristics of carbon (C) and nitrogen (N) in different organs or layers, such as leaves, branches, trunks, roots, understory vegetation, litter, and soil within a forest ecosystem, have remained poorly understood. In this study, four age groups of Pinus massoniana natural forest including young, middle-aged, near-mature, and mature were selected as research subjects to illustrate the C and N stoichiometry interactions among different layers and organs in the forest ecosystem. The results showed that the average C and N concentrations in the leaves of the tree layer, shrub layer, and herb aboveground parts (HAP) were higher than that of other tree and shrub organs, as well as the herb underground parts (HUP), respectively. The N concentrations of tree branches and trunks showed a trend of increase first and decrease later from young to mature phases, but the C:N ratios presented an opposite trend. The C concentrations.in all tissues in shrubs showed a first decline and then a rise with age. As age progressed, the N concentration in each ecosystem layer increased gradually and demonstrated high synergy. The mineralization of organic matter in the soil was generally slow. The C concentrations in the understory vegetation layer were significantly positively correlated with the C concentrations in the litter layer but negatively correlated with the soil layer, and the C concentrations in the litter layer were also significantly negatively correlated with the C concentrations in the soil layer. The research findings can provide a reference basis for the formulation of nutrient regulation and sustainable management measures in the natural forests of P. massoniana in the study area.

Positive tipping points for the sustainable growth of bivalve shellfish mariculture in England and Wales

Shellfish mariculture, the farming of marine bivalve shellfish, is a highly sustainable form of food production, which contributes significantly to the rural, coastal economies of England and Wales, and has considerable potential for growth. To unlock this potential, we explored the application of the positive tipping points (PTP) framework in an invited stakeholder workshop comprising key policy makers, regulators, industry representatives and academic researchers. Stakeholders mapped environmental and socio-economic factors constraining shellfish mariculture and identified key opportunities (leverage points) for positive intervention. The workshop focused on five case studies from southwest England addressing key constraints identified for the shellfish industry, including “licencing”, “spatial planning” and/or “classification” of shellfish sites and cultured species. These case studies presented new data on the effectiveness of a range of interventions: i) catchment scale, and ii) nature-based, solutions for water quality management in the Exe estuary; iii) risk-based methods for assuring shellfish quality/safety in the Camel estuary; iv) evidence gathering on ecosystem services (habitat provisioning) by shellfish mariculture in Lyme Bay and, v) policy developments on licencing of Pacific oysters in England. Stakeholders highlighted opportunities for new guidance, innovative tools and technology to aid environmental monitoring, regulation and quality assurance for shellfish mariculture and for tradeable ecosystem services beyond food production (including nutrient regulation, coastal protection and habitat provisioning). These and other interventions identified by stakeholders (including product diversification and market development) were then prioritised and sequenced for optimal implementation. Actions, actors and enabling conditions were identified using the PTP framework to realise prioritised opportunities.

Boosting cadmium tolerance in Phoebe zhennan: the synergistic effects of exogenous nitrogen and phosphorus treatments promoting antioxidant defense and root development.

Plants possess intricate defense mechanisms to resist cadmium (Cd) stress, including strategies like metal exclusion, chelation, osmoprotection, and the regulation of photosynthesis, with antioxidants playing a pivotal role. The application of nitrogen (N) and phosphorus (P) fertilizers are reported to bolster these defenses against Cd stress. Several studies investigated the effects of N or P on Cd stress in non-woody plants and crops. However, the relationship between N, P application, and Cd stress resistance in valuable timber trees remains largely unexplored. This study delves into the Cd tolerance mechanisms of Phoebe zhennan, a forest tree species, under various treatments: Cd exposure alone, combined Cd stress with either N or P and Cd stress with both N and P application. Our results revealed that the P application enhanced root biomass and facilitated the translocation of essential nutrients like K, Mn, and Zn. Conversely, N application, especially under Cd stress, significantly inhibited plant growth, with marked reductions in leaf and stem biomass. Additionally, while the application of P resulted in reduced antioxidant enzyme levels, the combined application of N and P markedly amplified the activities of peroxidase by 266.36%, superoxide dismutase by 168.44%, and ascorbate peroxidase by 26.58% under Cd stress. This indicates an amplified capacity of the plant to neutralize reactive oxygen species. The combined treatment also led to effective regulation of nutrient and Cd distribution in roots, shoots, and leaves, illustrating a synergistic effect in mitigating toxic impact of N. The study also highlights a significant alteration in photosynthetic activities under different treatments. The N addition generally reduced chlorophyll content by over 50%, while P and NP treatments enhanced transpiration rates by up to 58.02%. Our findings suggest P and NP fertilization can manage Cd toxicity by facilitating antioxidant production, osmoprotectant, and root development, thus enhancing Cd tolerance processes, and providing novel strategies for managing Cd contamination in the environment.

Targeted cultivation of diatoms in mariculture wastewater by nutrient regulation and UV-C irradiation.

Mariculture wastewater poses environmental challenges due to pollution and eutrophication. Targeted cultivation of diatoms in wastewater can help alleviate these issues while generating beneficial algae biomass, however reliable operating methods are lacking. We proposed a novel method for treating mariculture wastewater that employed UV-C irradiation and nutrient regulation to achieve targeted diatom cultivation. This study first examined growth of four diatom species (Nitzschia closterium, Chaetoceros muelleri, Cyclotella atomus, and Conticribra weissflogii) in mariculture wastewater. C. muelleri and C. weissflogii demonstrated better adaptability compared to N. closterium and C. atomus. Additionally, the growth and nutrient utilization of C. muelleri were studied under varying concentrations of silicate, phosphate, ammonium, and trace elements in wastewater. Optimal growth was observed at 500 μmol/L silicate, 0.6 mg/L phosphate, and 4 mg/L ammonium. Ammonium proved to be a more effective nitrogen source than urea and nitrate in promoting growth at this low level. Surprisingly, trace element supplementation did not significantly impact growth. Finally, this study utilized UV-C irradiation as a pre-treatment method for wastewater prior to nutrient adjustment, significantly enhancing the growth of C. muelleri. Overall, this study provides guidance on regulating key nutrients and pre-treatment method to optimize diatom biomass production from mariculture wastewater. This approach not only addresses environmental challenges associated with mariculture but also contributes to sustainable aquaculture practices through the recovery of valuable aquatic resources.

Selective logging impacts on soil microbial communities and functioning in Bornean tropical forest.

Rainforests provide vital ecosystem services that are underpinned by plant-soil interactions. The forests of Borneo are globally important reservoirs of biodiversity and carbon, but a significant proportion of the forest that remains after large-scale agricultural conversion has been extensively modified due to timber harvest. We have limited understanding of how selective logging affects ecosystem functions including biogeochemical cycles driven by soil microbes. In this study, we sampled soil from logging gaps and co-located intact lowland dipterocarp rainforest in Borneo. We characterised soil bacterial and fungal communities and physicochemical properties and determined soil functioning in terms of enzyme activity, nutrient supply rates, and microbial heterotrophic respiration. Soil microbial biomass, alpha diversity, and most soil properties and functions were resistant to logging. However, we found logging significantly shifted soil bacterial and fungal community composition, reduced the abundance of ectomycorrhizal fungi, increased the abundance of arbuscular mycorrhizal fungi, and reduced soil inorganic phosphorous concentration and nitrate supply rate, suggesting some downregulation of nutrient cycling. Within gaps, canopy openness was negatively related to ectomycorrhizal abundance and phosphomonoesterase activity and positively related to ammonium supply rate, suggesting control on soil phosphorus and nitrogen cycles via functional shifts in fungal communities. We found some evidence for reduced soil heterotrophic respiration with greater logging disturbance. Overall, our results demonstrate that while many soil microbial community attributes, soil properties, and functions may be resistant to selective logging, logging can significantly impact the composition and abundance of key soil microbial groups linked to the regulation of vital nutrient and carbon cycles in tropical forests.

Impacts of forest age on soil characteristics and fertility quality of Populus simonii shelter forest at the southern edge of the Horqin Sandy Land, China.

The sand fixing shelter forests in the Horqin Sandy Land are a key area in the "3-North" Shelter Forest Program in China, which has a history of over 50 years of artificial afforestation. Populus simonii Carr is one of the most dominant silvicultural species in the region. The aim of this study is to understand the soil characteristics and soil fertility of Populus simonii shelter forests at different growth stages and to establish a scientific basis for soil nutrient regulation and sustainable management of Populus simonii shelter forests at the southern edge of the Horqin Sandy Land. Sample plots were selected for young (≤15 a), middle-aged (16-25 a), near-mature (26-30 a), mature (31-40 a), and over-mature (≥41 a) forests. Each forest studied was in a state of natural restoration with uniform stand conditions and no artificial fertilizer was applied. These sites were selected to study changes in the soil characteristics in soil depths of 0-20, 20-40, and 40-60 cm. In order to avoid the problem of multicollinearity between soil variables and to reduce redundancy, principal component analysis (PCA), Pearson's correlation analysis, and Norm value calculation were used to select the least correlated indicators with the highest factor loadings. This was used to establish the minimum data set. The soil fertility quality of these shelterbelts in different forest ages was quantified using the soil quality index (SQI). In the growth stage from young to nearly mature forests, the soil bulk weight and pH decreased with increasing forest age. Soil capillary porosity, noncapillary porosity, total porosity, water content, field water holding capacity, and organic carbon content increased with increasing forest age and soil nutrient content gradually improved. At the stage of near-mature to over-mature forests, the effect of forest age on soil bulk density was not significant and all other soil characteristics decreased to varying degrees as the forest age increased. The soil also developed from alkaline to neutral. The SQI of the total data set and the SQI of the minimum data set consistently showed that near-mature forests (NMF) > middle-aged forests (MAF) > mature forests (MF) > over-mature forests (OMF) > young forests (YF). The results of the two evaluation systems showed a significant positive correlation (P < 0.05, R 2 = 0.8263) indicating that it is feasible to use the minimum data set to evaluate the soil fertility of shelter forests of different forest ages. The age of the forest has an obvious effect on the soil characteristics and overall soil fertility of shelter forests. The Populus simonii shelter forests on the southern edge of the Horqin Sandy Land have great soil development at the early stage of afforestation and the soil nutrient content gradually increases. The soil fertility reaches a peak when the forest is nearly mature and the soil fertility declines after the age of the forest reaches 30 years.

Influence of Nutrient Regulation on Ricebean (Vigna umbellata (Thunb.) Ohwi and Ohashi) Growth and Dry Matter

Aims: Within the realm of sustainable agriculture and its attendant issues, there exists a compelling need for a viable approach to cropping systems that integrates pragmatic and economically sound crop management tactics. This is imperative to uphold land productivity and secure a lasting provision of crops for human consumption. Acknowledging the pivotal contribution of organic manure when combined with chemical fertilizers in crop cultivation and the safeguarding of soil well-being, a research inquiry was formulated for a noteworthy cropping sequence.&#x0D; Study Design: Randomized block design.&#x0D; Place and Duration: School of Agricultural Sciences, Nagaland University, Medziphema. Duration: 2019-2021.&#x0D; Methodology: The study took place from 2019 to 2021 at the School of Agricultural Sciences (SAS), Medziphema Campus in Nagaland. The primary aim was to assess the lasting impact of both manure and fertilizers on yield and soil condition in a ricebean system over this two-year duration. In the second week of April in both 2019 and 2020, Dhaincha (Sesbania aculeata), a green manure crop, was sown using seeds. After a 30-day decomposition period, this green manure was incorporated into the soil. Soil samples were collected from the upper 0-15 cm layer of each experimental plot and analyzed. The experimental field was laid out in randomized block design with three level of organic manures i.e., poultry manure (PM), pig manure (PGM) and farm yard manure (FYM) along with doses of inorganic fertilizers : 100% RDF, 75% RDF, 50% RDF. The treatment combinations included T1 : GM (Sesbania) + PM (0.7 t ha-1) + 100 % RDF; T2: GM (Sesbania) +PM (0.7 t ha-1) + 75 % RDF; T3: GM (Sesbania) + PM (0.7 t ha-1) + 50 % RDF ; T4: GM (Sesbania) + PGM (0.7 t ha-1) + 100 % RDF; T5: GM (Sesbania) +PGM (0.7 t ha-1) + 75% RDF; T6: GM (Sesbania) + PGM (0.7 t ha-1) + 50 % RDF; T7: GM (Sesbania) +FYM (4 t ha-1) + 100 % RDF; T8: GM (Sesbania) + FYM (4 t ha-1) + 75 % RDF; T9: GM (Sesbania) +FYM (4 t ha-1) + 50 % RDF.&#x0D; Results: In treatment T1, which involved the application of a blend of green manure and poultry manure at a rate of 0.7 tons per hectare, coupled with a full dose of RDF, exhibited outstanding outcomes in ricebean cultivation. This resulted in elevated seed yields, improved seed quality, sustained soil health, and maximized economic gains for farmers in the foothill conditions of Nagaland.&#x0D; Conclusion: The substantial enhancement in ricebean growth parameters can be credited to the rich nutrient content and beneficial micronutrients present in poultry manure. combining Recommended Dose of Fertilizers (RDF) with poultry manure, known for its ability to boost nodule formation in legumes, improved soil fertility, fostered beneficial microbial activity, and promoted legume health, ultimately leading to higher yields. In contrast, farmyard manure (FYM) outperformed pig manure due to its balanced nutrients, microbial activity, organic matter, and positive impact on soil quality, creating an optimal environment for plant growth. Poultry manure's capacity to stimulate nodule formation, enhance soil fertility, and support legume health resulted in increased nitrogen fixation and improved yields in leguminous crops, fostering early root development and robust growth in ricebean crops.

The Role of Cryptogams in Soil Property Regulation and Vascular Plant Regeneration: A Review

Despite their small size, cryptogams (lichen, liverwort, and moss) are important for ecosystem stability. Due to their strong stress resistance, cryptogams often cover extreme environments uninhabitable for vascular plants, which has an important impact on the material cycle and energy flow of various terrestrial ecosystems. In this article, we review and discuss the effects of cryptogams on soil properties (moisture and fertility) and vascular plant regeneration over the past two decades. Cryptogams strongly affect soil water content by influencing precipitation infiltration, non-rainfall water input, soil evaporation, soil water holding capacity, and soil permeability, ultimately helping to reduce soil water content in areas with low annual precipitation (&lt;500 mm). However, in areas with high annual precipitation (&gt;600 mm) or where the soil has other water sources, the presence of cryptograms is conducive to soil water accumulation. Cryptogam plants can increase soil fertility and the availability of soil nutrients (TOC, TN, TP, TK, and micronutrients) in harsh environments, but their effects in mild environments have not been sufficiently investigated. Cryptogam plants exert complex effects on vascular plant regeneration in different environments. The primary influence pathways include the physical barrier of seed distribution, shading, allelopathy, competition, influences on ectomycorrhizal development and individual reproduction, and the regulation of soil water content, temperature, and nutrients.

Mapping and assessment of lake ecosystem services in Lithuania

Lakes provide essential Ecosystem Services (ES) that support human well-being. However, due to anthropogenic environmental degradation, lake ecosystem conditions and related ES supply are affected. To assess these impacts and ES supply alterations, mapping and assessing lake ES is key. Spatiotemporal lake ES studies are lacking, especially at the national scale. In this study, we mapped and assessed lake ES nationally in Lithuania. In total, 1032 lakes were considered. The supply of five ES were studied in 1990, 2000, 2006, 2012, and 2018: 1) fibres and other materials for construction (fibres ES); 2) water for non-drinking purposes (water ES); 3) the maintenance of nursery populations (nursery ES); 4) the maintenance of freshwater chemical conditions (nutrient regulation ES), and 5) direct and indirect cultural outputs (recreation ES). For fibres ES, an increase over time was observed, following an increase in reed areas around the lakes. The results showed that significant differences among periods were identified in all ES except for water ES supply. Generally, the supply of fibres, nutrient, nursery and recreation ES increased between 1990 and 2018. Spatially, the north-eastern, central and easternmost parts of Lithuania showed a high supply of multiple ES (e.g., fibres ES, nutrient ES), while the western parts of the country were seen as essential for nursery ES supply. Except for water ES supply, all ES showed a clustered pattern. The hot–cold spots identified followed the areas of high and low ES supply. Bundle analysis identified three clusters. Recreation ES supply was not associated with fibres, nursery, nutrient, and water ES supply. Fibres, nursery, and nutrient ES supply were not related to water ES supply. The results obtained in this work are critical for better management and help to identify lakes that supply high and low ES.

Characterization of expression response in post-prandial situation of food sensing system in rainbow trout (Oncorhynchus mykiss) fed a plant-based diet: Focus on free fatty acid receptors and their signaling pathways

Recently identified and characterized in rainbow trout (Oncorhynchus mikyss), the main gustatory receptors for fatty acid, known as free fatty acids receptor (FFAR) 1 and 2, may play a crucial role in nutrient detection and regulation of feeding behavior. However, our understanding of their post-prandial roles remains limited. This study investigates the impact of a single meal (acute effect) with an alternative plant-based diet (vegetal diet, V diet devoid of fish meal and fish oil) on the food detection mechanisms in trout. After 30 days of feeding with commercial-like diet (C diet made up of a mix of fish meal, fish oil and plant ingredients) followed 5 days of fasting, we conducted a post-prandial kinetic experiment after single meal with C or V diet. We assessed the expression pattern of ffar genes, their associated signaling pathways (calcium and indolamine pathways) in the tongue along with the expression pattern of appetite-regulating neuropeptides in the hypothalamus. Additionally, we evaluated central activity through brain activity markers in the telencephalon of trout at various post-meal time points, including 20 min, 2, 6, 10 and 24 h. Our results revealed that the diet nature (C vs V) influences the expression of ffar genes, while some paralogs of ffar2 (ffar2a2 and ffar2b1.2) were early up-regulated by V diet, ffar2b1.1 and ffar1 were latter up-regulated by C diet. Differential regulations in the tongues of V diet fish were also observed on calcium signaling and an early alteration in serotonin turnover. The expression increase of neuropeptide npya from 6 to 10 h after meal, could suggest a greater sensation of hunger in fish fed the C diet. Finally, our findings suggest that rainbow trout exhibit a keen ability to detect a novel feed after a single meal with V diet at the brain level, particularly in areas associated with decision-making and behavior control. Altogether, results not only show that the integrative feeding response appears to be dysregulated by V diet, but also highlight the noteworthy sensitivity of nutrient detection mechanisms in rainbow trout to new food sources. FFARs may play a role in finely discerning diets with varying levels of ω-3 LC-PUFAs in rainbow trout. This heightened detection sensitivity holds the potential to significantly influence the regulation of feeding behavior and food detection in farmed fish.

Effects of wetland connectivity on overwintering and movement behaviours of Australian freshwater turtles

AbstractFreshwater turtles are important consumers in Australian freshwater ecosystems. They serve as scavengers, nutrient regulators, and as food sources and Totems for Traditional Owners throughout Australia. Despite their importance, most Australian freshwater turtle species are declining. The impact of winter wetland drying on turtle populations remains unknown, and winter exposure of hibernating turtles may be an important additional source of mortality. We aimed to examine turtle responses to seasonal and episodic wetland drying in wetlands using acoustic telemetry and active trapping. Wetlands were chosen that spanned a range of hydrological connectivity to the adjacent Edward/Kolety‐Wakool River. We found that tagged Emydura macquarii typically exit wetlands disconnected from the adjacent permanent river prior to winter, and overwinter in the river. Female E. macquarii rapidly re‐entered ‘home’ wetlands (wetlands in which they were initially tagged) the following spring, whereas males tended to leave the study area, returning occasionally. Although we were not able to evaluate a winter drying event, one of the wetlands experienced partial summer drying. All three local turtle species (E. macquarii, Chelodina expansa, C. longicollis) exited the wetland long before winter drying would have become a potential threat. Our results suggest that turtles in this system may be protected from winter wetland drying because they move to the adjacent permanent river prior to winter. Spending the winter in the river channel reduces the risks of being trapped in a drying wetland as temperatures drop in winter.

Establishment and application of high throughput screening cell model for nutrient regulation of embryonic development

Embryo development exerts far-reaching influence on pregnancy outcome, postnatal development and lifelong health. Thereafter, to select functional nutrients to improve embryo development is of great importance. Herein, a stable porcine trophectoderm cell line expressing a luciferase reporter gene driven by a 1,009 bp PCNA gene promoter was constructed through lentiviral transduction and G418 selection. A high throughput screening assay was subsequently developed using the stable reporter cell line to screen a library of 225 nutrients. Seven nutrients with a minimum Z-score of 2.0 were initially identified to be capable of enhancing embryonic development. Among these nutrients, resveratrol, apigenin, and retinol palmitate were furtherly confirmed the beneficial effects for embryo development. Resveratrol significantly increased the expression of key genes involved in pTr cell proliferation and the number of S-phase cells. Resveratrol was furtherly confirmed to promote the expression of key genes in trophoblast development and increase embryo adhesion rate in vitro. Similarly, dietary 0.05% resveratrol supplementation significantly increased the number of embryo attachment and serum level of P4 and E2 in rats. Resveratrol could also improve maternal antioxidant levels and reduce intracellular ROS. Collectively, a high throughput screening cell model for nutrient regulation of embryonic development was established, which can be used to highly effectively select the potential candidates for embryo development. These findings have great implications for exploring optimal functional nutrients to improve embryo development, ultimately beneficial for pregnancy outcome, offspring postnatal development and lifelong health for human beings and mammalian animals.

Nutrient use efficiency has decreased in southwest China since 2009 with increasing risk of nutrient excess

The optimal application of nutrients, such as nitrogen and phosphorus, to the soil is crucial for achieving high crop yields with minimal environmental impact. However, the effect of spatio-temporal changes in soil nutrient supply on crop yield is poorly understood in China. Here, we present a framework that combines environmental data, fertilizer field experiments, and machine learning to estimate the rice yield responses to different nutrient conditions and overall farmland nutrient sustainability in southwest China from 2009 to 2019. The results show that the fertilizer input has contributed to the long-term increase in rice yield over the past ten years. The fertilizer use has increased rice yield by 2.3–2.4 tons per hectare per year. However, the nutrient use efficiency decreased, with the fertilizer contribution ratio declining from 29.3% in 2009 to 27.5% in 2019. Further, 19% of the rice-growing farmlands are at risk of nutrient excess, and 36% are at risk of nutrient degradation. Controlling nitrogen and phosphorus input is key to nutrient regulation, and our approach may guide the sustainable use of nutrient resources on farmlands.

Field assessment of the potential for small scale co-cultivation of seaweed and shellfish to regulate nutrients and plankton dynamics

The co-cultivation of seaweed alongside shellfish has the potential to regulate local dissolved nutrient concentrations and consequently affect plankton dynamics. Evidence for this has until now come largely from computational modelling and laboratory studies, rather than field studies. Here we report on weekly/bi-weekly profiling of inorganic nutrient concentrations (nitrate, nitrite, ammonium, phosphate, and silicate) over two years (2019–2020) at three sampling stations across a small-scale (16 ha) kelp and mussel farm in Porthallow Bay, Cornwall, UK. Nutrient concentrations were measured in conjunction with a range of related environmental variables, including water temperature, salinity, clarity, and phyto- and zoo- plankton abundance, biomass and community composition. These environmental data were also supplemented with river discharge data. Our results indicate typical seasonal variations in chemical (nutrient), physical (hydrographic), and biological (plankton) parameters across all three sampling stations and no significant reductions in inorganic nutrient concentrations in the water column downstream from the integrated kelp and shellfish farm. We conclude that the effectiveness of nutrient regulation by integrating seaweed and shellfish aquaculture will depend on local climatic and hydro-geochemical conditions (affecting background nutrient inputs), as well as the design and scale of integrated multi–trophic aquaculture (IMTA) systems.

Cancer Metabolism under Limiting Oxygen Conditions.

Molecular oxygen (O2) is essential for cellular bioenergetics and numerous biochemical reactions necessary for life. Solid tumors outgrow the native blood supply and diffusion limits of O2, and therefore must engage hypoxia response pathways that evolved to withstand acute periods of low O2 Hypoxia activates coordinated gene expression programs, primarily through hypoxia inducible factors (HIFs), to support survival. Many of these changes involve metabolic rewiring such as increasing glycolysis to support ATP generation while suppressing mitochondrial metabolism. Since low O2 is often coupled with nutrient stress in the tumor microenvironment, other responses to hypoxia include activation of nutrient uptake pathways, metabolite scavenging, and regulation of stress and growth signaling cascades. Continued development of models that better recapitulate tumors and their microenvironments will lead to greater understanding of oxygen-dependent metabolic reprogramming and lead to more effective cancer therapies.

As green infrastructure, linear semi-natural habitats boost regulating ecosystem services supply in agriculturally-dominated landscapes

Semi-natural linear landscape elements, such as hedgerows, are vital structures within agricultural landscapes that have an impact on ecosystem processes and support biodiversity. However, they are typically omitted from green infrastructure planning, which could lead to significant undervaluing of landscapes and their multifunctionality in terms of ecosystem service supply. Using the InVEST (Integrated Valuation of Ecosystem Services and Tradeoffs) model suite, we tested the effects of additionally including semi-natural linear landscape elements on the model outcomes for crop pollination, nutrient regulation, erosion regulation and water flow regulation ecosystem services supply. The results showed that linear semi-natural landscape elements contribute positively to the landscape’s multifunctionality. Small changes have been identified for water flow regulation, whereas, considering both spatial extent and magnitude of the changes, the greatest changes have been found with respect to the supply of pollination and nutrient regulation. Direct proximity of the linear elements had the greatest effect on ecosystem service supply, in particular with regard to pollination. Based on our results, a more pronounced consideration of semi-natural linear landscape elements as an important element of green infrastructure is advisable.

Water-potassium coupling at different growth stages improved kiwifruit (Actinidia spp.) quality and water/potassium productivity without yield loss in the humid areas of South China

Precise water and nutrient regulation are the key to improving fruit quality and water productivity for kiwifruit orchards in Central Sichuan's hilly region where seasonal drought is becoming increasingly severe. Here, an experiment was set up to clarify how water-potassium coupling at different growth stages affects kiwifruit yield, water/potassium productivity and quality. A conventional fertigation was set as the control treatment (CK), and two water deficit treatments (60% and 80% CK, denoted as LW and HW, respectively) with three potassium (K) deficit levels (40%, 60% and 80% CK, denoted as LK, MK and HK, respectively) were applied at each growth stage of the cultivar “Jinyan” kiwifruit. The phenolic compounds and key enzyme activities were evaluated, in addition to the yield and traditional physical and nutritional properties. Results showed that the water and K deficit would reduce the yield of kiwifruit, however the yield of HWMK treatments at stages I and II showed no significant differences compared with CK (P > 0.05), HWMK treatment at stage III even increased the fruit yield. Water productivity (WP) and K partial factor productivity (KPFP) showed a trend of HW>LW, and reached the highest in HWMK treatment at all growth stages. The physical qualities were more affected by water, especially at stages I and II. HWMK treatments at stages I and II significantly increased fruit firmness by 30.20% and 21.56%, respectively (P < 0.05). Whereas, kiwifruit nutritional qualities were more affected by K, especially at stage III. Specifically, compared with CK, III-HWHK treatment significantly elevated vitamin C (Vc), total soluble solids (TSS), sugar/acid ratio, and total phenolic compounds by 22.45%, 30.58%, 24.91% and 54.87%, respectively (P < 0.05). Water-potassium coupling had significant effects on all five key quality-related enzyme activities (P < 0.05), except for the effect of water on ascorbate oxidase (AAO) activity (P > 0.05). The correlation analysis revealed a highly significant correlation between fruit nutritional qualities and key enzyme activities (P < 0.01), indicating that water-potassium coupling influenced nutritional quality by regulating the enzyme activity involved in metabolic processes. Principal component analysis (PCA) confirmed the results of correlation analysis, and found that HWMK treatment at stages I and II and HWHK treatment at stage III were most efficient in improving kiwifruit nutritional qualities. Overall, the stimulatory effect of fruit qualities to water-potassium coupling was growth stage dependent, water-potassium coupling affected fruit quality by regulating the enzyme activity. HWMK treatment at stages I and II and HWHK treatment at stage III were most efficient in improving fruit quality and water/potassium productivity without yield loss under water and fertilizer saving conditions, which could be suggested as the optimal strategy of fertigation in the humid areas of South China.