Effects of lead exposure on salivary glands of rats: insights into the oxidative biochemistry and glandular morphology

Environmental Science and Pollution Research - This study aimed to investigate the effects of lead (Pb) exposure on parotid and submandibular glands through morphological aspects as well as the...     

Trophic and reproductive biochemistry of a deep-sea gelatinous octopus, Opisthoteuthis calypso

The present study provides a comprehensive analysis of the biochemical composition (proximate composition, amino acids and fatty acids in gonad, digestive gland and muscle) of the cirrate octopod, Opisthoteuthis calypso, collected off the coast of Portugal. Protein and energy contents of O. calypso were significantly lower (p < 0.05) than those observed for coastal octopods, suggesting that the gelatinous musculature of the cirrate octopus may not be a direct consequence of food limitation, but rather associated with reduced selective pressure for strong swimming ability in the deep sea. Moreover, principal component analyses of fatty acid (FA) data clearly separated coastal octopods from O. calypso. Saturated FA biomarkers (namely 16:0, 17:0, 18:0) and monounsaturated FA 22:1 suggest a higher phytodetrital influence on diet of O. calypso. A clear separation between groups was also observed with amino acid (AA) data. However, essential AA and non-essential AA designations (based on the flow of carbon through biochemical systems) do not necessarily provide an accurate picture of the origins of amino nitrogen in the deep-sea environment. Consequently, the interpretation of the present data is a challenging task but opens a new window of opportunity to unravel new trophic biomarkers in the deep sea.     

Toxicological effects of N,N,N′,N′-tetramethylethylenediamine on electric eel (Electrophorus electricus) acetylcholinesterase and human serum butyrylcholinesterase

This study examined the adverse effects of N,N,N′,N′-tetramethylethylenediamine (TEMED) on electric eel (Electrophorus electricus) acetylcholinesterase (AChE) and human serum butyrylcholinesterase (BChE). Data show that TEMED inhibited AChE in electric eel as well as human serum BChE. Kinetic studies indicated that the inhibition produced by TEMED in both sources was of mixed type, i.e. K_m increased and V _max decreased in a concentration-dependent manner. K_I (constant of ChE–substrate–TEMED complex into ChE–substrate complex and TEMED) was estimated to be 0.674 mM for electric eel and 0.024 mM for human serum BChE. The γK_m (dissociation constant of ChE–substrate–TEMED complex into ChE–TEMED complex and substrate) was 0.083 and 0.2 mM for electric eel AChE and human serum BChE, respectively. The IC₅₀ for electric eel and for human serum ChE was 1.57 and 0.043 mM, respectively. The present results suggest that TEMED produced adverse effects on electric eel and human serum via inhibition of ChE.     

Quantification of 17 endocrine disruptor compounds and their spatial and seasonal distribution in the Iberian Ave River and its coastline

The Ave River flows through the most urbanized and industrialized Porto district areas. Despite ovotestis was recently reported in male fish from the estuary, no data exist on the water levels of natural and pharmaceutical estrogens (17β-estradiol, estrone, and 17α-ethynylestradiol), xenoestrogenic industrial pollutants (4-octylphenol, 4-nonylphenol and their mono and diethoxylates, and bisphenol A), phytoestrogens (formononetin, biochanin A, daidzein, and genistein), and sitosterol. Absence of analyses applies to the river, estuary, and nearby coastline. Those compounds mimic the action of endogenous estradiol, being well-recognized endocrine disrupters (EDCs). To conclude about suspected influxes of estrogenic EDCs into the river and coastline, water samples were taken at eight sites every two months, during one year (2010), at low tide. Data showed ubiquitous presence of potentially hazardous amounts of estrogens (particularly ethynylestradiol, up to 10 ng L^?1), nonylphenol (up to 250 ng L^?1), and sitosterol (up to 6 μg L^?1), which helps explaining the ovotestis emergence in local fish. Also, because physicochemical parameters used in water quality evaluation, such as pH, dissolved oxygen, nitrates, and nitrites levels, were within legal limits – suggesting good quality – our study supports that assessment of human and environmental risks by targeting surface waters requires integrating EDCs monitoring in routine analyses.     

Turning the game around: toxicity in a nudibranch-sponge predator–prey association

Escalation theory proposes enemy-related selection as the most relevant factor of natural selection among individual organisms. When hazardous to predators, prey might be considered enemies that influence predator evolution. Opisthobranch molluscs that prey on chemically defended prey are an interesting study case on this subject. Predation on chemically defended species paved the way for opisthobranchs to enter in an arms race, developing means to detoxify and/or excrete harmful compounds, which led to the sequestration of those compounds and their self-defensive use, an escalation of defenses. Here we aim to understand whether the opisthobranch predator is better protected than its chemically defended prey, using as predator–prey model, a nudibranch (Hypselodoris cantabrica) and the sponge it preys upon (Dysidea fragilis), and from which it obtains deterrent chemical compounds. Specimens of both species were collected on the Portuguese coast, and their crude extracts were analyzed and used in palatability tests. Nudibranchs revealed a higher natural concentration of crude extract, probably due to a progressive accumulation of the compounds. Both predator and prey extracts revealed similar mixtures of deterrent metabolites (furanosesquiterpenes). Palatability tests revealed a more effective deterrence in the nudibranch extracts because significant rejection rates were observed at lower concentrations than those necessary for the sponge extracts to have the same effect. We concluded that the predator is chemically better protected than its prey, which suggests that its acquisition of chemical defenses reveals a defensive escalation.     

Logistic regression and fuzzy logic as a classification method for feral fish sampling sites

This study presents a classification method combining logistic regression and fuzzy logic in the determination of sampling sites for feral fish, Nile Tilapia (Tilapia rendalli). This method statistically analyzes the variable domains involved in the problem, by using a logistic regression model. This in turn generates the knowledge necessary to construct the rule base and fuzzy clusters of the fuzzy inference system (FIS) variables. The proposed hybrid method was validated using three fish stress indices; the Fulton Condition Factor (FCF) and the gonadossomatic and hepatossomatic indices (GSI and HSI, respectively), from fish sampled at 3 different locations in the Rio de Janeiro State. A multinomial logistic regression allowed for the FIS construction of the proposed method and both statistical approaches, when combined, complemented each other satisfactorily, allowing for the construction of an efficient classification method regarding feral fish sampling sites that, in turn, has great value regarding fish captures and fishery resource management.     

The spatial ecology of juvenile loggerhead turtles (Caretta caretta) in the Indian Ocean sheds light on the “lost years” mystery

While our understanding of the early oceanic developmental stage of sea turtles has improved markedly over recent decades, the spatial context for this life history stage remains unknown for Indian Ocean loggerhead turtle populations. To address this gap in our knowledge, 18 juvenile loggerheads were satellite tracked from Reunion Island (21.2°S, 55.3°E) between 2007 and 2011. Nine turtles swam north toward Oman (20.5°N, 58.8°E), where one of the world’s largest rookeries of loggerheads is located. Three individuals traveled south toward South Africa and Madagascar, countries that also host loggerhead nesting grounds. Fourteen of the transmitters relayed diving profiles. A dichotomy between diurnal and nocturnal diving behavior was observed with a larger number of shorter dives occurring during the day. Diving behavior also differed according to movement behavior as individuals spent more time in subsurface waters (between 10 and 20 m) during transit phases. The study provides an understanding of the oceanic movement behavior of juvenile loggerheads in the Indian Ocean that suggests the existence of an atypical trans-equatorial developmental cycle for the species at the ocean basin scale in the Indian Ocean. These results address a significant gap in the understanding of loggerhead oceanic movements and may help with the conservation of the species.     

Effects of recreational diving on early colonization stages of an artificial reef in North-East Atlantic

Increasing interest for recreational SCUBA diving worldwide is raising the concern about its potential effects on marine ecosystems. Available literature is still much focused either on impacts on coral reefs of tropical regions or on diver’s behaviour underwater. In this study we analysed, through photo-quadrats, the benthic community composition in a section of a decommissioned Portuguese navy ship that was sunk for touristic purposes. The ship broke down and became separated in two sections enabling a Control versus Impact sampling design, as one section is less attractive for diving. Gorgonians (mainly belonging to the species Leptogorgia sarmentosa and Eunicella verrucosa) were the taxa more negatively affected in the dived ship section, with smaller coverage and size. More resilient species such as the acorn barnacle Amphibalanus amphitrite were positively correlated with the Impact samples. In the case of the study area, according to the available data, 70% or more of the total amount of dives are now on the sunken ships. From these results, lessons can be taken to apply on natural reefs and related management plans.     

Health risks of potentially toxic trace elements in urban soils of Manaus city,Amazon, Brazil

Environmental Geochemistry and Health - The city of Manaus is the biggest industrial city of the north Brazilian region, and a haphazard urbanization process characterizes it. The continuous...