Hypoxia-driven selective degradation of cellular proteins in jumbo squids during diel migration to the oxygen minimum zones

The jumbo squid, Dosidicus gigas, is an oceanic top predator in the eastern tropical Pacific that undergoes diel vertical migrations into mesopelagic oxygen minimum zones (OMZs). Besides glycogen breakdown, the pathways of the squid’s metabolic (suppression) strategy are poorly understood. Here, juvenile D. gigas were exposed to oxygen levels found in the OMZ off Gulf of California (1 % O₂, 1 kPa at 10 °C) with the aim to identify, via proteomic tools, eventual anaerobic protein degradation as potential energy source at such depths. Under hypoxia, total protein concentration decreased nonsignificantly from 79.2 ± 12.4 mg g^?1 wet mass to 74.7 ± 11.7 mg g^?1 wet mass (p > 0.05). Yet, there was a significant decrease in heat-shock protein (Hsp) 90 and α-actinin contents (p < 0.05). The lower α-actinin concentration at late hypoxia was probably related to decreased protection of the Hsp90 chaperon machinery resulting in increased ubiquitination (p < 0.05) and subsequent degradation. Thus, the present findings indicate that D. gigas might degrade, at least under progressing hypoxia, specific mantle proteins anaerobically to increase/maintain anaerobic ATP production and extend hypoxia exposure time. Moreover, the ubiquitin–proteasome system seems to play an important role in hypoxia tolerance, but further investigations are necessary to discover its full potential and pathways.     

Analyzing Spatio-temporal Land Cover Dynamics in an Atlantic Forest Portion Using Unsupervised Change Detection Techniques

Environmental Modeling & Assessment - Over the past decades, the Southeast Atlantic Forest in Paraíba do Sul River Valley has suffered intense deforestation and human disturbances. Due to...     

Assessing the trophic state of Linhos lake: a first step towards ecological rehabilitation

Lack of recognition of the value of wetlands has led to the loss of considerable areas of these ecosystems in the past. Linhos lake (Figueira da Foz, Portugal) is a good example of one of these ecosystems, in which human intervention was responsible for its environmental degradation and led to its precocious terrestrialization. Physico-chemical conditions and zooplankton community structure were studied in Linhos lake, in order to evaluate ecosystem functioning and to acquire baseline information. The system is characterised by high oxygen depletion. Spatial heterogeneity was confirmed by the existence of significant differences in total densities for the three zooplanktonic groups. Rotifers were the most abundant group attaining their maximum density in April (2251 x 1 ind/l). Keratella quadrata, K. cochlearis, Polyarthra vulgaris, Filinia terminalis and Hexarthra mira were the main abundant species. Correspondence analysis suggested temperature as the main controlling factor in species seasonality. In order to prevent the precocious disappearance of the lake some restoration measures were proposed based on zooplankton community structure.     

Optimal Space-time Coverage and Exploration Costs in Groundwater Monitoring Networks

A method to determine the optimal subset of stations from a reference level groundwater monitoring network is proposed. The method considers the redundancy of data from historical time series, the times associated with the total distance required to run through the entire monitoring network, and the sum of the times for each monitoring station. The method was applied to a hypothetical case-study consisting of a monitoring network with 32 stations. Cost-benefit analysis was performed to determine the number of stations to include in the new design versus loss of information. This optimisation problem was solved with simulated annealing. Results showed that the relative reduction in exploration costs more than compensates for the relative loss in data representativeness.     

Yeasts as a model for assessing the toxicity of the fungicides Penconazol, Cymoxanil and Dichlofluanid

In the present work the sensitivity of yeast strains of Kluyveromyces marxianus, Pichia anomala, Candida utilis, Schizosaccharomyces pombe and Saccharomyces cerevisiae, to the fungicides cymoxanil, penconazol, and dichlofluanid, was evaluated. Dichlofluanid induced the most negative effects, whereas penconazol in general was not very toxic. Overall, our results show that the parameters IC50 for specific respiration rates of C. utilis and S. cerevisiae and C(D) for cell viability of S. cerevisiae can be applied to quantify the toxicity level of the above compounds in yeast. Hence, could be explored as an alternative or at least as a complementary test in toxicity studies and, therefore, its potential for inclusion in a tier testing toxicity test battery merits further research.     

Remediation potential of caffeine,oxybenzone, and triclosan by the salt marsh plants <Emphasis Type="Italic">Spartina maritima</Emphasis> and <Emphasis Type="Italic">Halimione portulacoides</Emphasis>

Pharmaceuticals and personal care products (PPCPs) have attracted increasing concern during the last decade because of their widespread uses and continuous release to the aquatic environment. This work aimed to study the distribution of caffeine (CAF), oxybenzone (MBPh), and triclosan (TCS) when they arrive in salt marsh areas and to assess their remediation potential by two different species of salt marsh plants: Spartina maritima and Halimione portulacoides. Experiments were carried out in the laboratory either in hydroponics (sediment elutriate) or in sediment soaked in elutriate, for 10 days. Controls without plants were also carried out. CAF, MBPh, and TCS were added to the media. In unvegetated sediment soaked in elutriate, CAF was mainly in the liquid phase (83%), whereas MBPh and TCS were in the solid phase (90% and 56%, respectively); the highest remediation was achieved for TCS (40%) and mainly attributed to bioremediation. The presence of plants in sediment soaked in elutriate-enhanced PPCPs remediation, decreasing CAF and TCS levels between approximately 20-30% and MBPh by 40%.. Plant uptake, adsorption to plant roots/sediments, and bio/rhizoremediation are strong hypothesis to explain the decrease of contaminants either in water or sediment fractions, according to PPCPs characteristics.     

Effects of air/fuel ratio on gas emissions in a small spark-ignited non-road engine operating with different gasoline/ethanol blends

This study investigates the effects of several blends of gasoline and anhydrous ethanol on exhaust emission concentrations of carbon monoxide (CO), total hydrocarbons (HCs), and nitrogen oxides (NO_x) from a small spark-ignited non-road engine (SSINRE). Tests were carried out for different air/fuel equivalence ratios as measured by lambda (λ). A 196 cm³ single-cylinder four-stroke engine-generator operating at a constant load of 2.0 kW was used; pollutant gas concentrations were measured with an automatic analyzer similar to those typically used in vehicle inspections. The results showed that as the ethanol content of the mixture increased the concentrations of CO, HCs, and NO_x reduced by 15, 53, and 34%, respectively, for values of λ < 1 (rich mixture) and by 52, 31, and 16% for values of λ > 1 (lean mixture). Overall, addition of anhydrous ethanol to the gasoline helped to reduce emissions of the pollutant gases investigated, what contributes to photochemical smog reduction and quality of life in urban areas.     

Mechanical properties of shotcrete with addition of sugarcane bagasse fiber and ash

Journal of Material Cycles and Waste Management - Shotcrete is a sprayed concrete placed on steep slopes that have been widely used because it can prevent surface weathering and erosion, and in...     

Ultracentrifugation as a direct method to concentrate viruses in environmental waters: virus-like particle enumeration as a new approach to determine the efficiency of recovery

Some health important enteric viruses are considered to be emerging waterborne pathogens and so the improvement of detection of these viruses in the aquatic environment is one of the most important steps in dealing with these pathogens. Since these viruses may be present in low numbers in water, it is necessary to concentrate water samples before viral detection. Although there are several methods to concentrate viruses in environmental waters, all present some drawbacks and consequently the method should be chosen that, despite its limitations, is adequate to achieve the aim of each study. As the effectiveness of the concentration methods is evaluated by determining the efficiency of viral recovery after concentration, it is important to use a simple and effective approach to evaluate their recovery efficiency. In this work ultracentrifugation, usually used as a secondary step for virus concentration, was evaluated as the main method to concentrate directly viruses in environmental water samples, using the microscopic enumeration of virus-like particles (VLP) as a new approach to estimate the efficiency of recovery. As the flocculation method is currently employed to concentrate viruses in environmental waters, it was also used in this study to assess the efficiency of the ultracentrifugation as the main viral concentration method in environmental waters. The results of this study indicate that ultracentrifugation is an adequate approach to concentrate viruses directly from environmental waters (recovery percentages between 66 and 72% in wastewaters and between 66 and 76% in recreational waters) and that the determination of VLP by epifluorescence microscopy is a simple, fast and cheap alternative approach to determine the recovery efficiency of the viral concentration methods.