Legume nodule senescence is a poorly understood process involving a decrease in N2 fixation and an increase in proteolytic activity. Some physiological changes during nodule aging have been reported, ...but scarce information is available at the subcellular level.
Biochemical, immunological and proteomic approaches were used to provide insight into the effects of aging on the mitochondria and cytosol of nodule host cells.
In the mitochondria, the oxidative modification of lipids and proteins was associated with a marked decline in glutathione, a reduced capacity to regenerate ascorbate, and upregulation of alternative oxidase and manganese superoxide dismutase. In the cytosol, there were consistent reductions in the protein concentrations of carbon metabolism enzymes, inhibition of protein synthesis and increase in serine proteinase activity, disorganization of cytoskeleton, and a sharp reduction of cytosolic proteins, but no detectable accumulation of oxidized molecules.
We conclude that nodule mitochondria are an early target of oxidative modifications and a likely source of redox signals. Alternative oxidase and manganese superoxide dismutase may play important roles in controlling ROS concentrations and the redox state of mitochondria. The finding that specific methionine residues of a cytosolic glutamine synthetase isoform are sulfoxidized suggests a regulatory role of this enzyme in senescing nodules.
Summary
Primase‐polymerases (Ppol) are one of the few enzymes able to start DNA synthesis on ssDNA templates. The role of Thermus thermophilus HB27 Ppol, encoded along a putative helicase (Hel) ...within a mobile genetic element (ICETh2), has been studied. A mutant lacking Ppol showed no effects on the replication of the element. Also, no apparent differences in the sensitivity to DNA damaging agents and other stressors or morphological changes in the mutant cells were detected. However, the mutants lacking Ppol showed an increase in two to three orders of magnitude in their transformation efficiency with plasmids and genomic DNA acquired from the environment (eDNA), independently of its origin and G + C content. In contrast, no significant differences with the wild type were detected when the cells received the DNA from other T. thermophilus partners in conjugation‐like mating experiments. The similarities of this behaviour with that shown by mutants lacking the Argonaute (ThAgo) protein suggests a putative partnership Ppol‐ThAgo in the DNA–DNA interference mechanism of defence, although other eDNA defence mechanisms independent of ThAgo cannot be discarded.
In this study we analyzed the environmental and economic profile of current agricultural practices for greenhouse crops, in cold and warm climates in Europe, using four scenarios as reference ...systems: tomato crop in a plastic greenhouse in Spain, and in glasshouses in Hungary and the Netherlands, and rose crop in a glasshouse in the Netherlands. This study is in the context of the EUPHOROS project “Efficient Use of Inputs in Protected Horticulture”. The aim of EUPHOROS project is to improve horticultural production systems in Europe by developing cleaner production alternatives from both an environmental and economic point of view. The methodologies selected for the study were Life Cycle Assessment for the environmental analysis and cost-benefit analysis for the economic assessment. Dutch reference systems used a combined heat and power (CHP) system for the production of thermal energy and electricity. Two approaches were used to study the multifunctionality of CHP: system expansion and energy allocation. The main environmental burdens in the four scenarios were energy consumption, greenhouse structure and fertilizers. Environmental impacts due to energy consumption can be reduced by using co-generation or geothermal water in glasshouses. The structure contribution can be decreased with the improvement of recycled materials and design. Adjustment of fertilizer doses and closed irrigation systems are recommended in Spain and Hungary. The best economic perspectives to reduce inputs are energy savings in glasshouses and reduction of fertilizers in Spain and Hungary. The study shows the importance of including economic and environmental aspects in sustainability studies.
Consumers in Western markets are often called against foreign‐made products and their country‐of‐origin (COO), particularly against controversial COOs and products. As a result, Asian emerging ...countries and their manufacturing industries (e.g., apparel, toys, or chemicals) have become major targets of anti‐consumption in the West, with criticism rooted in political‐economic, social, and/or environmental issues. In addition, Western consumers' ethnocentric tendencies are often reinforced by campaigning for domestic product/service alternatives. This backdrop raises questions about the degree of consumers' macro COO knowledge and ethnocentrism, and of their importance as levers of consumer concern about (i.e., risk perceptions) and anti‐consumption of foreign products from a controversial COO. This article thus sheds light on the extent to which COO knowledge (whether macro or based on usage experience), along with consumer ethnocentrism, can be considered antecedents of two risk perception types and, in turn, of country‐driven anti‐consumption (CDAC)—in the context of this work, Spanish consumers' reluctance to buy and (non‐)ownership of Chinese apparel products. The findings reveal that consumer ethnocentrism heightens both psycho‐social and performance risk perceptions and contributes to reluctance to buy. Macro COO knowledge affects CDAC only indirectly through performance risk perceptions. By contrast, usage experience attenuates both performance and psycho‐social risk perceptions and directly affects foreign product ownership. Risk perceptions predict and mediate most of the effects of COO knowledge, consumer ethnocentrism, and usage experience on CDAC outcomes. Implications for research, policy, and practice are also discussed.
COVID-19 is certainly the first sustainability crisis of the 21st century. The paper examines the impact of COVID-19 on the Indian stock and commodity markets during the different phases of lockdown. ...In addition, the effect of COVID-19 on the Indian stock and commodity markets during the first and second waves of the COVID-19 spread was compared. A comparative analysis of the stock market performances and sustainability of selected South Asian countries is also included in the study, which covers the lockdown period as well as the time frame of the first and second waves of COVID-19 spread. To examine the above relationship, the conventional Welch test, heteroskedastic independent t-test, and the GMM multivariate analysis is employed, on the stock return, gold prices, and oil prices. The findings conclude that during the different phases of lockdown in India, COVID-19 has a negative and significant impact on oil prices and stock market performance. However, in terms of gold prices, the effect is positive and significant. The results of the first wave of COVID-19 infection also corroborate with the above findings. However, the results are contradictory during the second wave of coronavirus infection. Furthermore, the study also substantiates that COVID-19 has significantly affected the stock market performances of selected South Asian countries. However, the impact on the stock market performances was only for a short period and it diminished in the second wave of COVID-19 spread in all the selected South Asian countries. The findings contribute to the research on the stock and commodity market impact of a pandemic by providing empirical evidence that COVID-19 has spill-over effects on stock markets and commodity market performances. This result also helps investors in assessing the trends of the stock and commodity markets during the pandemic outbreak.
Main Conclusion We studied the response of Eugenia myrtifolia L. plants, an ornamental shrub native to tropical and subtropical areas, to salt stress in order to facilitate the use of these plants in ...Mediterranean areas for landscaping. E. myrtifolia plants implement a series of adaptations to acclimate to salinity, including morphological, physiological and biochemical changes. Furthermore, the post-recovery period seems to be detected by Eugenia plants as a new stress situation. Different physiological and biochemical changes in Eugenia myrtifolia L. plants after being subjected to NaCl stress for up to 30 days (Phase I) and after recovery from salinity (Phase II) were studied. Eugenia plants proved to be tolerant to NaCl concentrations between 44 and 88 mM, displaying a series of adaptative mechanisms to cope with salt-stress, including the accumulation of toxic ions in roots. Plants increased their root/shoot ratio and decreased their leaf area, leaf water potential and stomatal conductance in order to limit water loss. In addition, they displayed different strategies to protect the photosynthetic machinery, including the limited accumulation of toxic ions in leaves, increase in chlorophyll content, changes in chlorophyll fluorescence parameters, leaf anatomy and antioxidant defence mechanisms. Anatomical modifications in leaves, including an increase in palisade parenchyma and intercellular spaces and decrease in spongy parenchyma, served to facilitate CO2 diffusion in a situation of reduced stomatal aperture. Salinity produced oxidative stress in Eugenia plants as evidenced by oxidative stress parameters values and a reduction in APX and ASC levels. Nevertheless, SOD and GSH contents increased. The post-recovery period is detected as a new stress situation, as observed through effects on plant growth and alterations in chlorophyll fluorescence and oxidative stress parameters.
Repetitiveness in project's activities has gained an important role in the construction industry. Multiple linear scheduling methods have been proposed in order to fully take advantage of the spatial ...and temporal information these type of project can provide to practitioners. Besides the advances in the optimization models in these fields, to the extent of the authors knowledge, there is still pending a complete and flexible mathematical linear programming formulation that allow practitioners to easily and jointly solve the Resource allocation, Resource-Constrained Project Scheduling and Time-Cost Tradeoff problem, taking into account as many scheduling properties, benefits and challenges that linear scheduling of repetitive activities imply. This paper shows a complete guide and computational experimentation, of a novel mathematical model that can be easily used by practitioners to optimize construction schedules considering to the largest extent the time and space conditions repetitive projects offer. Particularly, it contributes to the repetitive activities scheduling body of knowledge by successfully implementing a robust linear programing optimization model in a real construction project, while considering as much linear scheduling characteristics as possible. It proves that relationships in the sub-activity level, continuity conditions, multiple modes of execution, controlled acceleration routines and execution mode shifts, and multiple crews can be easily and jointly integrated to a linear optimization model by adding simple linear restrictions to the model.
•A mathematical formulation to optimally solve the RCPSP and TCTP in repetitive activities in construction projects.•The model considers multiple modes of execution and number of crews.•The model serves as a guideline for practitioners willing to implement linear programming in their scheduling process.•The model considers relationships on sub-activity level, continuity conditions, multiple modes, crews, and controlled shifts.•The model shows that real conditions are easily integrated by adding simple restrictions to the model.•Schedules generated by the model are robust, largely reflecting realistic construction project site conditions.•The model can be used for scheduling pipeline, highway and high-rise building projects.
The rooting of stem cuttings is a common vegetative propagation practice in many ornamental species. A detailed analysis of the morphological changes occurring in the basal region of cultivated ...carnation cuttings during the early stages of adventitious rooting was carried out and the physiological modifications induced by exogenous auxin application were studied. To this end, the endogenous concentrations of five major classes of plant hormones auxin, cytokinin (CK), abscisic acid, salicylic acid (SA) and jasmonic acid and the ethylene precursor 1‐aminocyclopropane‐1‐carboxylic acid were analyzed at the base of stem cuttings and at different stages of adventitious root formation. We found that the stimulus triggering the initiation of adventitious root formation occurred during the first hours after their excision from the donor plant, due to the breakdown of the vascular continuum that induces auxin accumulation near the wounding. Although this stimulus was independent of exogenously applied auxin, it was observed that the auxin treatment accelerated cell division in the cambium and increased the sucrolytic activities at the base of the stem, both of which contributed to the establishment of the new root primordia at the stem base. Further, several genes involved in auxin transport were upregulated in the stem base either with or without auxin application, while endogenous CK and SA concentrations were specially affected by exogenous auxin application. Taken together our results indicate significant crosstalk between auxin levels, stress hormone homeostasis and sugar availability in the base of the stem cuttings in carnation during the initial steps of adventitious rooting.
Climate change is considered a serious threat to agriculture and food security. It is linked to rising temperatures and water shortages, conditions that are expected to worsen in the coming decades. ...Consequently, the introduction of more drought-tolerant crops is required. Quinoa (
Chenopodium quinoa
Willd.) has received great attention worldwide due to the nutritional properties of its seeds and its tolerance to abiotic stress. In this work, the agronomic performance and seed nutritional quality of three quinoa varieties were studied during two consecutive years (2019-2020) under three water environmental conditions of Southwestern Europe (irrigated conditions, fresh rainfed, and hard rainfed) with the goal of determining the impact of rainfed conditions on this crop performance. High precipitations were recorded during the 2020 growing season resulting in similar grain yield under irrigation and fresh rainfed conditions. However, in 2019, significant yield differences with penalties under water-limiting conditions were found among the evaluated environmental conditions. Furthermore, nutritional and metabolomic differences were observed among seeds harvested from different water environments including the progressive accumulation of glycine betaine accompanied by an increase in saponin and a decrease in iron with water limitation. Generally, water-limiting environments were associated with increased protein contents and decreased yields preserving a high nutritional quality despite particular changes. Overall, this work contributes to gaining further knowledge about how water availability affects quinoa field performance, as it might impact both seed yield and quality. It also can help reevaluate rainfed agriculture, as water deficit can positively impact the nutritional quality of seeds.
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