Environmentally relevant bisphenol A concentrations effects on the seagrass Cymodocea nodosa different parts elongation: perceptive assessors of toxicity

Environmental Science and Pollution Research - Toxicity data on bisphenol A (BPA) effects on aquatic macrophytes remain scarce. Therefore, environmentally relevant BPA concentrations (0.03, 0.1,...     

Occupational and public health and safety in a changing work environment: An integrated approach for risk assessment and prevention

During recent years the work environment has undergone significant changes regarding working time, years of employment, work organization, type of employment contracts and working conditions. In this paper, consequences of these changes on occupational and public health and safety are examined. These include the disruption of human biological rhythms, the increase of workers fatigue due to changes in patterns of working hours and years of employment, job insecurity and occupational stress, which have a serious impact on workers’ health and may result in an increase in occupational accidents. Unsafe work practices related to workload and time pressure, the impact of work changes on public safety and the deterioration of workers’ living conditions with respect to income, social-family life, health and insurance benefits, are also described. In this context, difficulties that occur due to the changing work environment in conducting effective occupational risk assessments and implementing OSH measures are discussed (for example, frequent changes between tasks and workplaces, underreporting of occupational accidents and diseases, lack of methodological tools, etc.). A fundamental criterion used while studying consequences on health and safety and the relative preventive measures is that health and safety must be approached as ‘the promotion and maintenance at the highest degree of the physical, mental and social well-being of workers’ and not only as retention of their work ability. Limits in combining “flexibility” at work and overall protection of occupational and public safety and health in a competitive market are put forward for discussion.     

Molecular characterization of denitrifying bacteria isolated from the anoxic reactor of a modified DEPHANOX plant performing enhanced biological phosphorus removal

Enhanced Biological Phosphorus Removal (EBPR) under anoxic conditions was achieved using a Biological Nutrient Removal (BNR) system based on a modification of the DEPHANOX configuration. Double-probe Fluorescence in Situ Hybridization (FISH) revealed that Polyphosphate Accumulating Organisms (PAOs) comprised 12.3 +/- 3.2% of the total bacterial population in the modified DEPHANOX plant. The growing bacterial population on blood agar and Casitone Glycerol Yeast Autolysate agar (CGYA) medium was 16.7 +/- 0.9 x 10(5) and 3.0 +/- 0.6 x 10(5) colony forming units (cfu) mL(-1) activated sludge, respectively. A total of 121 bacterial isolates were characterized according to their denitrification ability, with 26 bacterial strains being capable of reducing nitrate to gas. All denitrifying isolates were placed within the alpha-, beta-, and gamma-subdivisions of Proteobacteria and the family Flavobacteriaceae. Furthermore, a novel denitrifying bacterium within the genus Pseudomonas was identified. This is the first report on the isolation and molecular characterization of denitrifying bacteria from EBPR sludge using a DEPHANOX-type plant.     

Seasonal and local variation of Cr, Ni and Co concentrations in Ulva rigida C. Agardh and Enteromorpha linza (Linnaeus) from Thermaikos Gulf, Greece

Cobalt, nickel and chromium concentrations were determined in Enteromorpha linza and Ulva rigida in seawater and sediment after seasonal collection from Thermaikos Gulf, Greece. Industrial waste and sewage is poured into this Gulf. The relative abundance of metals in the seaweeds and seawater decreased in the order Ni > Cr > Co, whereas in the sediment the order was Cr > Ni > Co. The two seaweeds bioaccumulated similar metal concentrations. The seasonal variation of metals in the two algae was not significant, but seemed to depend on the growth dynamics, the age of the tissue, the metal concentrations in the environment and the abiotic factors (such as salinity and temperature). Only Cr concentrations in E. linza showed significant local variation which depended on the area into which the industrial and domestic wastes were discharged and on their transport by sea currents. Nickel and chromium concentrations in U. rigida and Cr concentrations in E. linza displayed significant positive correlation with their concentrations in the seawater. Concentrations of the three metals in the seaweeds and seawater of Thermaikos Gulf generally exceeded the 'background' levels.     

Phytoplankton community structure changes during autumn and spring in response to environmental variables in Methana,Saronikos Gulf,Greece

Environmental Science and Pollution Research - Phytoplankton community was investigated during two contrasting periods using offshore plankton samples in the volcanic area of Methana peninsula...     

Copper bioaccumulation,photosystem II functioning,and oxidative stress in the seagrass <Emphasis Type="Italic">Cymodocea nodosa</Emphasis> exposed to copper oxide nanoparticles

Photosynthetic activity, oxidative stress, and Cu bioaccumulation in the seagrass Cymodocea nodosa were assessed 4, 12, 24, 48, and 72 h after exposure to two copper oxide nanoparticle (CuO NP) concentrations (5 and 10 mg L^?1). CuO NPs were characterized by scanning electron microscopy (SEM) and dynamic light scattering measurements (DLS). Chlorophyll fluorescence analysis was applied to detect photosystem II (PSII) functionality, while the Cu accumulation kinetics into the leaf blades was fitted to the Michaelis-Menten equation. The uptake kinetics was rapid during the first 4 h of exposure and reached an equilibrium state after 10 h exposure to 10 mg L^?1 and after 27 h to 5 mg L^?1 CuO NPs. As a result, 4-h treatment with 5 mg L^?1 CuO NPs, decreased the quantum yield of PS II photochemistry (Φ _PSΙΙ ) with a parallel increase in the regulated non-photochemical energy loss in PSII (Φ _NPQ ). However, the photoprotective dissipation of excess absorbed light energy as heat, through the process of non-photochemical quenching (NPQ), did not maintain the same fraction of open reaction centers (q _p ) as in control plants. This reduced number of open reaction centers resulted in a significant increase of H₂O₂ production in the leaf veins serving possibly as an antioxidant defense signal. Twenty-four-hour treatment had no significant effect on Φ _PSΙΙ and q _p compared to controls. However, 24 h exposure to 5 mg L^?1 CuO NPs increased the quantum yield of non-regulated energy loss in PSII (Φ _NO ), and thus the formation of singlet oxygen (¹O₂) via the triplet state of chlorophyll, possible because the uptake kinetics had not yet reached the equilibrium state as did 10 mg L^?1. Longer-duration treatment (48 and 72 h) had less effect on the allocation of absorbed light energy at PSII and the fraction of open reaction centers, compared to 4-h treatment, suggesting the function of a stress defense mechanism. The response of C. nodosa leaves to CuO NPs fits the “Threshold for Tolerance Model” with a threshold time (more than 4 h) required for induction of a stress defense mechanism, through H₂O₂ production.     

Biological properties of mud extracts derived from various spa resorts

Spa resorts are known for thousands of years for their healing properties and have been empirically used for the treatment of many inflammatory conditions. Mud is one of the most often used natural materials for preventive, healing and cosmetic reasons and although it has been used since the antiquity, little light has been shed on its physical, chemical and biological properties. In this study we examined the effect of mud extracts on the expression of adhesion molecules (CAMs) by endothelial cells as well as their effects on monocyte adhesion to activated endothelial cells. Most of mud extracts inhibited the expression of VCAM-1 by endothelial cells and reduced monocyte adhesion to activated endothelial cells, indicating a potent anti-inflammatory activity. Furthermore, the mud extracts were tested for their antimicrobial activity; however, most of them appeared inactive against S. aureus and S. epidermidis. One of the mud extracts (showing the best stabilization features) increased significantly the expression of genes involved in cell protection, longevity and hydration of human keratinocytes, such as, collagen 6A1, forkhead box O3, sirtuin-1, superoxide dismutase 1 and aquaporin-3. The present study reveals that mud exerts important beneficial effects including anti-inflammatory and anti-aging activity as well as moisturizing effects, implicating important cosmeceutical applications.     

Microtubule integrity and cell viability under metal (Cu,Ni and Cr) stress in the seagrass Cymodocea nodosa

The effects of increasing Cu, Ni and Cr concentrations (0.5, 5, 10, 20 and 40 mg L⁻¹) on microtubule organization and the viability of leaf cells of the seagrass Cymodocea nodosa for 13 consecutive days were investigated under laboratory conditions. Increased oblique microtubule orientation, microtubule depolymerization at the 5–40 mg L⁻¹ Ni treatments after 3 d of exposure, and a complete microtubule depolymerization at all Ni treatments after 5 d were observed. Cu depolymerised microtubules after three to 7 d of exposure, while Cr caused an extensive microtubule bundling after 9 or 11 d of exposure, depending on metal dosage. Fluorescence intensity measurements further consolidated the above phenomena. Cell death, occurring at later time than microtubule disturbance, was also observed at all Cu and Ni treatments and at the 10–40 mg L⁻¹ Cr treatments and adding to the above quantification of the number of dead cells clearly showed that only a portion of the cell population studied died. The data presented, being the first assessment of microtubule disturbance in seagrasses, indicate that microtubules in seagrass leaf cells could be used as a valuable and early marker of metal-induced stress in biomonitoring programmes.