Antioxidant responses in the leaves of mercury-treated Eichhornia crassipes (Mart.) Solms.

Eichhornia crassipes (Mart.) Solms. plantlets were grown in 0.1 and 1.0 ppm treatment solutions of Hoagland’s hydroponic solutions modified with Hg(NO₃)₂ in order to examine the specific cellular and biochemical mechanisms involved in the tolerance of this plant exposed to mercury. This study assessed the responses of chloroplast pigments, i.e., carotenoids and chlorophylls, and evaluated the enzymatic and nonenzymatic antioxidant systems. Inductively coupled plasma-atomic emission spectrometry (ICP-AES) revealed varying Hg²⁺ levels in the young and mature leaf tissues, with greater amounts of Hg²⁺ found in the tissues of the young leaves. Total chlorophyll levels, notably those of chlorophyll a, chlorophyll b, and carotenoids, showed significant elevation in young leaf tissues, while a decrease in their levels was observed in mature leaf tissues in comparison to those of the control plants. These results lend support to the protective role of increased chlorophyll and carotenoid levels in the photosynthetic apparatus of young E. crassipes leaves in the presence of Hg²⁺. The antioxidant responses of Hg-treated E. crassipes plants were also measured, revealing a highly significant increase in catalase units, catalase and ascorbate peroxidase activities, and mercury-binding thiols in leaves from Hg-treated plants. Moreover, substantial differences in the degree of oxidative injury between the cells in leaves from the control and Hg-treated plants were evidenced by the lipid peroxidation activities monitored. The Hg-treatment-induced significant decrease in malondialdehyde (MDA) levels was observed in 0.1-ppm Hg(NO₃)₂-exposed plants, while a highly significant increase in MDA levels was noted in 1.0-ppm Hg(NO₃)₂-exposed plants. The high degree of lipid peroxidation at 1.0-ppm Hg treatment was evidently counteracted by the compensatory protective mechanism brought about by the increased levels in chloroplast pigments and the enhanced activities of the antioxidant systems. E. crassipes responded to mercury treatments by enhancing the synthesis of chlorophyll and carotenoid pigments, enzymatic, and nonenzymatic antioxidant substances, concomitantly increasing the antioxidative activities, thus rendering E. crassipes capable of tolerating Hg-induced stress. The potential of E. crassipes as a phytoremediator is evident.     

Phytoplankton dynamics with a special emphasis on harmful algal blooms in the Mar Piccolo of Taranto (Ionian Sea,Italy)

The response of phytoplankton assemblages to the closure of urban sewage outfalls (USOs) was examined for the Mar Piccolo of Taranto (Mediterranean Sea), a productive semi-enclosed coastal marine ecosystem devoted to shellfish farming. Phytoplankton dynamics were investigated in relation to environmental variables, with a particular emphasis on harmful algal blooms (HABs). Recent analyses evidenced a general reduction of the inorganic nutrient loads, except for nitrates and silicates. Also phytoplankton biomass (chlorophyll a) and abundances were characterized by a decrease of the values, except for the inner area of the basin (second inlet). The phytoplankton composition changed, with nano-sized species, indicators of oligotrophic conditions, becoming dominant over micro-sized species. If the closure of the USOs affected phytoplankton dynamics, however, it did not preserve the Mar Piccolo from HABs and anoxia crises. About 25 harmful species have been detected throughout the years, such as the potentially domoic acid producers Pseudo-nitzschia cf. galaxiae and P seudo-nitzschia cf. multistriata, identified for the first time in these waters. The presence of HABs represents a threat for human health and aquaculture. Urgent initiatives are needed to improve the communication with authorities responsible for environmental protection, economic development, and public health for a sustainable mussel culture in the Mar Piccolo.     

Long-term phenol, cresols and BTEX monitoring in urban air

This paper reports the results of a long-term monitoring of benzene, toluene, ethylbenzene, xylenes (BTEX), phenol and cresols in the air of Padua during a wide period of the year 2007 using two radial passive samplers (Radiello system) equipped with BTEX- and phenol-specific cartridges. Two sites were monitored, one in the industrial area and one close to the town centre. Relevant pollution episodes have been observed during both the winter and summer periods. Benzene, together with toluene, ethylbenzene and xylenes showed their maximum concentrations during the winter season, but the secondary pollutant phenol was higher than benzene for a large period of the year when the meteorological conditions blocked the pollutants in the lower layers of the atmosphere and solar radiation increased the benzene photo-oxidation process.     

Designing the Masoala National Park in Madagascar Based on Biological and Socioeconomic Data

Abstract: Conservation biologists have developed powerful tools for reserve selection and design over the past two decades, yet seldom are protected areas actually designed on scientific grounds. Using fundamental biological and socioeconomic principles of conservation science, we designed a new protected area and its multiple-use zone on the Masoala Peninsula in the humid forest zone of Madagascar. The explicit design criteria determined the data gathered for the work, which included (1) spatial distribution and quality of habitat, (2) the areas and species at greatest risk, (3) the relationship between environmental gradients and species distributions, (4) current and predicted human settlement and land and resource use, and (5) the economic potential of natural forest management as an alternative to deforestation. We used a geographic information system to integrate these data layers and applied the design criteria to develop a park proposal that balanced human and wildlife needs. The proposal won the approval of local residents, and a national decree in 1997 designated 2100 km² of rainforest and three satellite marine reserves as the Masoala National Park, with a surrounding multiple-use zone of approximately 1000 km². The new park is Madagascar's largest protected area and protects more lowland (<400 m) humid forest habitat than the entire reserve system combined, a significant step forward in conserving a globally important ecoregion. Consideration of local needs and the national economy was a key element in gaining approval for the Masoala Park. Such an approach toward reserve design could be applied elsewhere to improve chances of establishing and maintaining protected areas over the long term.     

An assessment of endocrine disrupting activity changes during wastewater treatment through the use of bioassays and chemical measurements.

The objective of this study was to assess the removal efficiencies of secondary wastewater treatment processes for compounds causing endocrine disrupting activity. The study used bioassays and chemical measurements, such as gas chromatography with mass spectrometry and enzyme immunosorbent assays. A total of seven full-scale water reclamation facilities using different unit operations and two pilot-scale membrane bioreactors were examined. Findings of this study imply that estrogenic disrupting activity in primary effluent is mainly caused by two steroidal hormones (17beta-estradiol and estriol) and, to a lesser extent, by synthetic chemicals, such as bisphenol A, 4-nonylphenol, and 4-tert-octylphenol. During secondary treatment, steroidal hormones were removed to a higher degree than nonylphenol and bisphenol A. The total estrogenic activity was removed by an average of 96%. The remaining concentrations of targeted steroids in secondary effluents, except for estriol, still had the potential to elicit a positive response in the human breast cell cancer assay. For the majority of facilities, the remaining activity was likely attributed to residual concentrations of two steroidal hormones (17beta-estradiol and estriol).     

Blends of (R)-3-hydroxyhexan-2-one and alkan-2-ones identified as potential pheromones produced by three species of cerambycid beetles

We present data indicating that three species of cerambycid beetles (subfamily Cerambycinae) produce the common cerambycine pheromone component (R)-3-hydroxyhexan-2-one as well as an alkan-2-one component, a possible new motif for cerambycid pheromone components. GC/MS analyses of headspace volatiles produced by male beetles indicated that Cyrtophorus verrucosus (Olivier) produced (R)-3-hydroxyhexan-2-one but also nonan-2-one at ~18 % of the hydroxyketone component, whereas Orwellion gibbulum arizonense (Casey) and Parelaphidion aspersum (Haldeman) produced decan-2-one at ~40 and 7 % of the amount of the hydroxyketone, respectively. In field bioassays, adult C. verrucosus were attracted by (R)-3-hydroxyhexan-2-one alone, but attraction was significantly enhanced by nonan-2-one. This effect was lost if the quantity of nonan-2-one exceeded 100 % of the hydroxyketone, suggesting that beetles could discern ratios of the two chemicals and were most strongly attracted to those approximating the blend produced by males. We suggest that nonan-2-one plays a role in the species specificity of the pheromone signal of C. verrucosus, and that decan-2-one plays a similar role in the semiochemical communication of O. g. arizonense and P. aspersum.     

Experimental evidence that workers recognize reproductives through cuticular hydrocarbons in the ant Odontomachus brunneus

Eusociality is characterized by a reproductive division of labor, wherein workers respond to the presence of reproductive individuals by refraining from reproduction themselves and restricting the reproductive efforts of others. Our understanding of how eusociality is maintained therefore depends on characterizing the mechanism by which workers detect the presence of a reproductive. Variations in cuticular hydrocarbons correspond to changes in reproductive ability in ants, and experimental studies are beginning to reveal the function of hydrocarbons as signals. In this study, we compare the cuticular hydrocarbon profiles of dominant and reproductive workers and queens of the ant Odontomachus brunneus with profiles of non-reproductive workers. Using split/reunification tests we document the existence of worker policing in both queenless and queenright colonies; supernumerary reproductives were treated aggressively by nestmates. Finally, we induce aggression and replicate queen-like submissive nestmate responses by supplementing the hydrocarbon profile of workers with (Z)-9-nonacosene, a compound that was significantly more abundant on the cuticles of reproductives. In three bioassays, we compare this manipulation to various control manipulations of the hydrocarbon profile and demonstrate that workers gauge the reproductive activity of nestmates through changes in their cuticular hydrocarbon profiles.     

TiO2-NPs and cadmium co-exposure: in vitro assessment of genetic and genomic DNA damage on Dicentrarchus labrax embryonic cells

Environmental Science and Pollution Research - The increased titanium dioxide nanoparticles (TiO2-NPs) spread and their interaction with organic and inorganic pollutants arouses concern for the...     

Observations in captivity of the activity patterns and resources utilization of the spider crab <Emphasis Type="Italic">Inachus phalangium</Emphasis> (Decapoda,Majidae)

The spider crab Inachus phalangium is common in the sublitoral fringe of the Mediterranean Sea and north-eastern Atlantic Ocean, where it can be found in association with the snakelocks sea anemone Anemonia viridis. Studies concerning its activity patterns and the role of the host sea anemone are lacking. Our study aimed at investigating activity rhythms and resources utilization of I. phalangium reared in captivity. The main behavioral traits exhibited by I. phalangium are performed mostly at night. Two experiments were designed, one examined the time budget of various behavioral acts and the degree of association with the sea anemone, the other analyzed the behavioral response to algae and anemones. We showed that algae have a crucial role in the biology of I. phalangium and that crabs are ready to leave the protection of their host to obtain them. Algae represent both the major component of the diet and one of the most utilized sources of masking material of I. phalangium, which provide, together with specialized cryptic behaviors, protection against predators. Although our data suggest that the association with A. viridis is not obligatory, but the role of the snakelocks sea anemone in the life of I. phalangium is still central, both as an anti-predatory defense and as a nutritional source. The association of I. phalangium with algae and the anemone is a facultative biotrophic commensalistic symbiosis.