Production and structure prediction of amylases from Chlorella vulgaris

Environmental Science and Pollution Research - Amylases are enzymes required for starch degradation and are naturally produced by many microorganisms. These enzymes are used in several fields such...     

Adaptation of a four-arm olfactometer for behavioural bioassays of large beetles

Summary. We adapted a four-arm olfactometer (55 × 55 × 5.5 cm) for bioassays of large insects and its usefulness was evaluated by testing the responses of three beetles, the palm weevil Rhynchophorus palmarum (L.) (Coleoptera: Curculionidea) and two Dynast scarabs Strategus aloeus (L.) and Oryctes rhinoceros (L.) (Coleoptera: Scarabaeidae) to plant odours and aggregation pheromones. This olfactometer was coupled to a volatile delivery system dispensing highly volatile semiochemicals at constant concentrations. We materialized airflows in the olfactometer by discolouring sensitive papers with acid vapours under various conditions (air straighten by stainless steel grids in inputs and output, 500 ml/min per arm) to visualize air turbulence and to test air-tightness. The volatile delivery system can be used to mix and dispense a broad range of concentrations of semiochemicals in air from diluted aqueous solutions. It was calibrated by measuring the release of the pheromone using solid phase-microextraction (SPME). Dose-response curves to synthetic pheromone were obtained for O. rhinoceros of both sexes. Coupling the volatile delivery system to the fourarm olfactometer provided a system with which the responses of R. palmarum and S. aloeus to their synthetic aggregation pheromones and to natural plant volatiles could be readily observed and studied.     

Converting Waste Polystyrene into Adsorbent: Potential Use in the Removal of Lead and Cadmium Ions from Aqueous Solution

Waste of polystyrene was converted into a cation exchange resin and was used for the removal of lead and cadmium metals from aqueous solution. Wastes consisting of coffee cups were crushed into small pieces and immersed into a solution of sulfuric acid in order to attach sulfonic group to polymer chain, these groups are responsible for the exchange properties of the modified plastic. The cation exchange capacity (CEC) was determined and was comparable to commercial exchangers. The adsorption isotherms of resin with synthetic wastewater containing lead and cadmium ions were tested. Adsorption analysis results obtained at various concentrations showed that the adsorption pattern on the resin followed Langmuir isotherms.     

Effects to perfluorooctane sulfonate (PFOS) on the mollusk Unio ravoisieri under laboratory exposure

To understand acute toxicity and oxidative stress of perfluorinated compounds in the freshwater ecosystems, we exposed freshwater mussels (Unio ravoisieri) to perfluorooctane sulfonate (PFOS), over a range of concentrations from 10 to 100?mg/L, in a laboratory experiment. Lethal concentration (LC50) was of about 65.9?mg/L after 96?h of exposure. The oxidative stress was assessed in gill and digestive gland of the freshwater mussels after 7 days of exposure to different nominal PFOS concentrations (C1=?2?mg/L, C2?=?6?mg/L and C3=?10?mg/L). C1 and C2 increased significantly (p?<?.05) the superoxide dismutase activity in both tissues compared, while the highest C3 decreased the enzyme activity. This implements an unfavourable response that highlights the excess of reactive oxygen species produced after contamination. The Catalase activity was also increased by about 40.05% and 66.63%, respectively, in gill and digestive gland after exposure to C3. The Malondialdehyde (MDA) level was increased in both gill and digestive gland in a concentration-dependent pattern. In contrast, the contamination of U. ravoisieri by PFOS did not affect the acetylcholinesterase activity in both organs (p?>?.005). These results provided information on potential biomarkers that could be effectively applied for the monitoring of freshwater ecosystem using indicator species such as U. ravoisieri.     

Numerical Simulation of Gas Injection in Vertical Water Saturated Porous Media

We present numerical simulations of drainage induced by air injection in a vertical water-saturated Hele-Shaw cell filled with glass microbeads. We use the macroscale Subsurface Transport Over Multiple Phases (STOMP) simulator developed by the Pacific Northwest National Laboratory’s Hydrology Group. To trigger fingering, we use random permeability fields consistent to capillary entry pressure fields. We compare the numerical results to our own experimental results shown in a previous study. We analyze the effects of the microheterogeneity degree as well as the macroscopic parameters on the gas saturation results. The main objective of the work is to investigate how microscopic effects could be accounted for by macroscopic variables during drainage.     

Chronic depression-like phenotype in male offspring mice following perinatal exposure to naturally contaminated eels with a mixture of organic and inorganic pollutants

Previously, we demonstrated that maternal exposure to high, intermediate, or lowly contaminated European eels with a mixture of chemicals, during pregnancy and lactation, resulted in adult despair-like behavior, selectively in male offspring mice. Here, we investigate if depression-like behavior in offspring males was transient or permanent by monitoring immobility behavior, a measure of behavioral despair, at three distinct stages of life, including young adult (post-natal day (PND) 55), mature adult (PND 200) and middle (PNDs 335–336) age, in the forced swimming (FST) and the tail suspension (TST) tests. Oxidative stress markers including malondialdehyde (MDA) levels and superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities were evaluated in the hippocampus, prefrontal cortex, and cerebellum of middle-aged animals. Findings showed a significant enhancement of immobility behavior in the TST performed at young adult age (all p < 0.05) in the FST carried out at mature adult age (all p < 0.001) and in both behavioral tests realized at middle age (all p < 0.05, except one p = 0.06) in mice perinatally exposed to eels compared with non-exposed controls. Antioxidant-related enzyme activities, including SOD and CAT, were only elevated in the hippocampus of middle-aged males perinatally exposed to the two more polluted eels (all p < 0.05). Further, lipid peroxidation, assessed by MDA levels, was not found to be differentially regulated in the selected areas of middle-aged brains of exposed mice (all p > 0.05). Collectively, this suggested limited oxidative metabolism disturbances in middle-aged brains exposed to eels. In summary, our results highlighted that offspring males perinatally exposed to naturally contaminated reared and river eels with persistent organic pollutants (POPs) and heavy metals displayed chronic depression-like phenotype. As extrapolation of data to humans should be done with precaution, retrospective and prospective epidemiological studies are needed to clarify this potential relationship, stressed in our animal model, between maternal polluted fish consumption and chronically low mood in offspring.

     

How renewable energy and service growth influence environmental quality: Evidence from a sustainable development perspective

The present study inspects the relationships between the carbon dioxide (CO₂) emissions, real GDP, renewable and non-renewable energy consumption, as well as the service growth for top ten countries (TTC) in service activities. The empirical modeling used in the study involves the procedures of cointegration and tests of Granger causality to inspect the dynamic interaction between the variables during the period from 1980 to 2018. The results of the present study suggest that the variables are cross-sectionally dependent. In addition, the variables appear to be cointegrated based on several tests. The long-run outcomes revealed an inversed U-shaped form between emissions-GDP proving the validity of the environmental Kuznets curve assumption. The fully modified ordinary least squares and dynamic OLS estimates show that the non-renewable energy and economic growth contribute to the increase of CO₂ emissions, while service value-added leads to decrease emissions. Furthermore, the renewable energy coefficient comes through as negative but insignificant for the selected panel. The TTC in service should stimulate the usage of renewable energy in various service events for following the path of sustainable development. Devising the investment plans associated with the use of renewable energies is quite essential for the advancement of the service sector leading to mitigating emissions portion.     

Effects of lead exposure on redox status,DNA and histological structures in Venus verrucosa gills and digestive gland

ABSTRACT

Lead (Pb) is one of the most toxic heavy metals that affect the physiological status of aquatic organisms. The present investigation evaluated the possible toxic effect of lead chloride (PbCl₂) on biomarkers responses, DNA damage and histological alterations in Venus verrucosa gills and digestive gland. Three concentrations of PbCl₂ (D1:1µgL^?1, D2: 10µgL^?1 and D3: 100µgL^?1) were chosen for V. verrucosa exposure during six days. At the end of the trial, it was found that Pb tended to accumulate in both gills and digestive gland in a dose-dependent manner. However, gill tissues exhibited the highest metal burden. Our results showed an increase of malondialdehyde, protein carbonyls and advanced oxidation protein product levels in both organs following PbCl₂exposure. The induction of both non-enzymatic and enzymatic antioxidant systems; as well as the decrease of the acetylcholinesterase activity and degradation of DNA structure was recorded in the gills and digestive gland. The histopathological alterations observed in gills (disruption of lamellas and cilia filaments?…) and digestive gland (lumens occlusion, necrosis and fibrosis) confirmed the aforementioned results. Our data highlighted the short-term toxicity effects of PbCl₂ on V. verrucosa and pointed out a high sensitivity of gills towards this metal.     

Conception of an environmental friendly O/W cosmetic emulsion from microalgae

The development of eco-friendly cosmetic such as those from microalgae for skin regeneration and collagen synthesis has gained a great interest worldwide. Accordingly, the potential of microalgae biomass as source of anti-aging cosmetic cream with high antioxidant activity has been investigated. Stabilities and sensory characteristics of cosmetic creams supplemented with Spirulina, Tetraselmis sp. and Dunaliella sp. at 0.5, 1.5 and 2.5%, respectively, revealed a conservation of physico-chemical and preliminary stability properties of formulations. To analyze physico-chemical and textural parameters, accelerated stability study was evaluated under two thermal conditions (25 and 40 °C) during 90 days. Results showed that pH values of all formulations were within the limits of normal skin pH range under storage time at 25 and 40 °C. During this period, the colored creams showed a significant changes of a* and b* indices, reflecting the instability of microalgae colors. Microalgae modified the textural characteristics of emulsions. The Tetraselmis sp. containing-cream had the lowest (P < 0.05)?values of hardness, springiness, and cohesiveness. The 0.5% Spirulina containing-cream had the best stable consistency and adhesiveness under time and temperature variations. It exhibited the best properties to be used for skin care products. Thanks to their high content in bioactive macromolecules, microalgae considerably improved the antioxidant activity of the new formulated skin creams.

     

Does a sanitary crisis drive oil prices and carbon emissions in the USA? Evidence from VECM modeling

Environment, Development and Sustainability - This study explores the interdependence among a sanitary crisis, environmental degradation, oil prices, and economic activity in the USA based on...