Chemical Extraction of Arsenic from Contaminated Soils in the Vicinity of Abandoned Mines and a Smelting Plant Under Subcritical Conditions

Under subcritical conditions, we studied the chemical extraction of arsenic (As) from contaminated soils that were sampled from the vicinity of abandoned mines and a smelting plant in South Korea. The total initial concentrations of As in the soil samples from the Myungbong and Cheongyang mines and the Janghang smelting plant were 298.6, 145.6, and 103.7 mg/kg, respectively. X-ray photoelectron spectroscopy analysis showed that the species of As identified in the soil was As(+V), including As₂O₅ and AsO₄ ^3? _. At 20°C, only 27.4, 26.5, and 40.1% of the total As was extracted from the Myungbong, Cheongyang, and Janghang soil samples, respectively, with 100 mM of NaOH. As the temperature was increased to 300°C, the extraction efficiencies remarkably increased. However, to achieve the complete extraction of As from the soils, 100 mM of citric acid, EDTA, or NaOH was needed at 200, 250, or 300°C. Extraction with subcritical water at 300°C resulted in incomplete extraction of As from the soils. The results of these experiments indicate that extraction mechanisms other than oxidative dissolution of As(+III) species may be responsible for the enhancement of As extraction. Our results suggest that subcritical water extraction combined with extracting reagents can effectively remediate As-contaminated soil regardless of the As species.     

Transient Gene Expression in Tobacco using Gibson Assembly and the Gene Gun

In order to target a single protein to multiple subcellular organelles, plants typically duplicate the relevant genes, and express each gene separately using complex regulatory strategies including differential promoters and/or signal sequences. Metabolic engineers and synthetic biologists interested in targeting enzymes to a particular organelle are faced with a challenge: For a protein that is to be localized to more than one organelle, the engineer must clone the same gene multiple times. This work presents a solution to this strategy: harnessing alternative splicing of mRNA. This technology takes advantage of established chloroplast and peroxisome targeting sequences and combines them into a single mRNA that is alternatively spliced. Some splice variants are sent to the chloroplast, some to the peroxisome, and some to the cytosol. Here the system is designed for multiple-organelle targeting with alternative splicing. In this work, GFP was expected to be expressed in the chloroplast, cytosol, and peroxisome by a series of rationally designed 5’ mRNA tags. These tags have the potential to reduce the amount of cloning required when heterologous genes need to be expressed in multiple subcellular organelles. The constructs were designed in previous work¹¹, and were cloned using Gibson assembly, a ligation independent cloning method that does not require restriction enzymes. The resultant plasmids were introduced into Nicotiana benthamiana epidermal leaf cells with a modified Gene Gun protocol. Finally, transformed leaves were observed with confocal microscopy.     

Benchmarking sustainability using indicators: An Indian case study

This paper develops an index to measure sustainability based on the broad themes of social, economy and environment. Nineteen appropriate indicators were selected based on relevance, data availability, and periodicity for each leg of sustainable development. A correlation analysis was carried out to assess relationships between the 19 indicators representing different parameters under the three themes. These parameters were then normalized using Z-score technique. The Z-scores computed for each of these parameters were then used to develop a Sustainable Development Index (SDI). The index is pilot tested on different States and Union Territories (UTs) of India. The values are compared and interpreted to adjudge the forerunners and laggards on the various dimensions of human well-being and environment. Significant relationships have been observed between income levels and area of administrative regions with sustainability indices of the regions. Smaller administrative regions with higher income levels have been observed with higher sustainability scores. The proposed index provides a useful measure of identifying problematic areas that can be plugged through policy measures and ensures that the region moves on sustainable development pathways.     

Environmental Kuznets curve estimation for NO2 emission: A case of Indian cities

Interaction between environmental degradation and economic growth is a growing matter of interest among policymakers. Here we have estimated environmental Kuznets curve (EKC) for 139 Indian cities considering NO₂ emissions. Study has been done for 2001–2013, and the data have been segregated by residential and industrial areas, and as well as low, medium, and high income areas. By virtue of different forms of EKC being found, policy level decisions have been designed. Moreover, non-rejection of EKC hypothesis reemphasized the impact of growth catalyzing economic policy decisions on environment.     

The dark side of the “redundancy hypothesis” and ecosystem assessment

Intricacy of biotic interactions (predator-prey relationship, strength of food web links and other type of intra- and inter-specific relationships), as well as shifts in species functions in ecosystems, could affect the accuracy of predictions derived from the theory of redundancy of species, when applied to ecosystems assessment.This opinion paper is based on three main considerations: 1) some fundamental differences between ecological and engineering definition of “redundancy”, underlying the main concerns related to the use frameworks derived from economical or engineering disciplines, as the ecosystems services paradigm; 2) presence of empirical obstacles to establish whether two different species are fully or partially redundant. When species redundancy in a particular community is estimated using a matrix with species-specific functional traits, often forgetting potential biotic interactions not directly related to the trophic chains or neglecting the variability in strengths of the links connecting these species; and 3) recent evidence offered by studies that shed doubts on the validity of the ecological redundancy hypothesis.Finally, we claim that more attention must to be paid to intrinsic ecological aspects of ecosystem components (per se values rather than derived values), and a precautionary principle is necessary for decisions related to the assessment of ecosystems.     

Autophagy in response to environmental stresses: New monitoring perspectives

Autophagy, an evolutionarily conserved process of cellular homeostasis in all eukaryotes, has been heavily implicated in many aspects of human health and diseases. However, its pivotal roles, particularly in stress and adaptive responses in other species in the environment, have perhaps not received the attention they deserve. Autophagy processes may underlie important ecological phenomena such as coral bleaching, as well as various forms of responses and adaptations to environmental forcing and deterioration. Investigating and assessing autophagy responses in the contexts of environmental stresses and ecological changes would therefore be important. Such investigations in indicator organisms could provide valuable parameters for ecosystems health assessment. Understanding autophagy responses in ecologically important species could also be useful in efforts of species and biodiversity conservation.     

The effects of K+ growth conditions on the accumulation of cesium by the bacterium Thermus sp. TibetanG6

The accumulation of cesium by the bacterium Thermus sp. TibetanG6 was examined under different K⁺ growth conditions. The effects of external pH and Na⁺ on the accumulation of cesium were also studied, and the mechanism involved was discussed. K⁺ regimes played an important role in the accumulation of cesium by the strain TibetanG6. The quantity of cesium accumulated (24 h) was much higher in K⁺-deficient regime than that in K⁺-sufficient regime. The pH and Na⁺ had different effects on the accumulation of cesium in the two K⁺ regimes. IR spectra analyses indicated that the biosorption is a process of homeostasis with cesium initially accumulated on the cell wall.