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Using the bivalve macrofouler Corbicula fluminea, the suitability of in vitro testing as a stepping stone towards the improvement of control methods based on chemical mixtures was addressed in this study. In vitro cholinesterase (ChE) activity inhibition following single exposure of C. fluminea tissue to four model chemicals (the organophosphates dimethoate and dichlorvos, copper and sodium dodecyl phosphate [SDS]) was first assessed. Consequently, mixtures of dimethoate with copper and dichlorvos with SDS were tested and modelled; mixtures with ChE revealed synergistic interactions for both chemical pairs. These synergic combinations were subsequently validated in vivo and the increased control potential of these selected combinations was verified, with gains of up to 50% in C. fluminea mortality relative to corresponding single chemical treatments. Such consistency supports the suitability of using time- and cost-effective surrogate testing platforms to assist the development of biofouling control strategies incorporating mixtures. [ABSTRACT FROM AUTHOR]

In twin pregnancy studies, molecular genetic techniques have rarely been used to determine zygosity, despite their known precision and accuracy. The present work aimed to assess the power of discrimination in zygosity assessment, using a set of microsatellite markers that were routinely used for aneuploidy screening by multiplex-PCR in a prenatal context. Rapid aneuploidy screening using a group of 20 microsatellite markers (STRs) located on chromosomes 13, 18, 21 and X has been performed in our lab for over 10 years, with a total of approximately 1,500 samples studied to date. A retrospective analysis of the 257 prenatal samples from multiple pregnancies was carried out. A subset of 14 cases presenting theoretical monozygosity were re-evaluated by the use of biostatistics tools accessed via the ZygProb website. Further monozygosity determination relative to dizygosity was calculated, given an estimated overall error value of 0.093%. The results show that monozygosity had been correctly determined in all our previously studied twins. This work demonstrates that accurate zygosity assessment can be achieved with the same STRs applied in aneuploidy screening with a high power of discrimination and a matching probability of over 99.999999%. [ABSTRACT FROM AUTHOR]

Although nesting ecology is well studied in crocodilians, there is little information on the diet and feeding habits of nesting females. During the annual dry season (November-December) of 2012, we studied the diet of female spectacled caiman (Caiman crocodilus) attending nests (n=33) and far from nests (n=16) in Piagaçu-Purus Sustainable Development Reserve (PPSDR), Central Amazonia, Brazil. The proportion of empty stomachs in nest-attending females was larger, and the occurrence of fresh food items was lower when compared to females not attending nests. Fish was the most frequent prey item for non-nesting females, while terrestrial invertebrates and snail operculae were the prey items most commonly recovered from stomachs of nesting females. Our study demonstrates that, despite enduring periods of food deprivation associated with nest attendance, nesting females of C. crocodilus still consume nearby available prey, possibly leaving their nest temporarily unattended. [ABSTRACT FROM AUTHOR]

Sooty mold is a complex of dark-pigmented fungi that covers leaves and branches of the olive tree (Olea europaea L.). This coverage can bring several consequences for the plant, such as decrease of the photosynthetic rate. Therefore, this study aims to understand the effect of sooty mold on fluorescence and gas exchange of olive leaves. Olive leaves were field-collected and histological, physiological (water content, fluorescence parameters, and carbon dioxide fluxes), and biochemical (osmolality; chlorophyll a, b, and a/b contents; and lipid peroxidation) analyses were performed in healthy leaves and in leaves covered with sooty mold. Histological analysis revealed a complex fungal hyphae proliferation on both leaf surfaces of covered leaves that predominated on the abaxial surface. Sooty mold-covered leaves showed significantly lower levels of water content and of basal (F0), maximal (Fm), and variable fluorescence (Fv). The proliferation of the sooty mold resulted in a decrease of fluorescence parameters, foliar free gas exchanges, and water content. Based on these results, we can conclude that sooty mold infection could affect light reaching leaves and the normal physiological metabolism of the plant (as photosynthesis) would be affected, with consequences for production. [ABSTRACT FROM AUTHOR]

ABSTRACT Procambarus clarkii (Girard, 1852) is a well-established invasive species in many worldwide aquatic ecosystems and is responsible for several ecological and economic impacts. This study examines the major factors responsible for its invasive dynamics in the international section of the River Minho (north-west Iberian Peninsula)., Data collected from June 2007 to May 2011 showed that abundance and biomass increased in the first 3 years of sampling, but suffered a decrease in the fourth year. Higher abundance and biomass were always found from May to October. These higher values have a clear relationship with water temperature and probably reflect higher activity and mobility., The sex-ratio was 1.08:1 in favour of females; eggs start to appear in May/June and the majority of juveniles in August/September., Information collected in this study is extremely important for future management actions that could be applied to this invasive species. Accordingly, we propose that control actions to minimize P. clarkii impacts in this system, such as intensive trapping, should be applied during late spring/early summer, when the catches are higher, the females are dominant, and before juvenile recruitment., Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Studies investigating the use of biomarkers in pesticide risk assessment have greatly increased in recent years; however, issues concerning the ecological meaning of enzymatic responses have proved controversial. Ideally a good biomarker response should be modulated by the environmental contaminants alone and demonstrate a predictable behavior towards certain types of toxins. As these premises are rarely observed, the present study aims to outline research that has contributed to an understanding of the behavior of two widely used biomarkers, cholinesterase and glutathione-S-transferase, describing environmental and biotic factors that affect their response in freshwater invertebrates. Studies were performed in the main classes of aquatic invertebrates with these biomarkers and conclusions were reached concerning their behavior towards the main classes of pesticides. Links between biomarker responses and conventional endpoints were evaluated so that ecological relevance could be attributed to enzymatic responses. Toxicity of mixtures was investigated, and cases of synergism and antagonism were pointed out as factors changing the expected toxicity of aquatic systems and leading to misinterpretations of biomarker responses. Finally, the use of biomarkers as a tool for biomonitoring and in situ assays was investigated, with discussion of advantages and disadvantages of their use. Environ. Toxicol. Chem. 2010;29:5–18. © 2009 SETAC [ABSTRACT FROM AUTHOR]

Microorganisms play a crucial role in decomposition processes and nutrient cycling and, therefore, in soil quality. Soil enzymes have shown sensitivity to contaminants, such as heavy metals, due to their interaction with the specific reaction sites, thereby reducing the formation of the reaction products. In this study, several enzymatic bioassays were applied (dehydrogenase, acid phosphatase, arylsulfatase, urease and B-glucosidase) to soils with different heavy metal contents, from the abandoned Jales mine (Portugal), before, during and after a rehabilitation process (years 2002, 2003 and 2004, respectively). Additionally, the mineralization of N and the microbial biomass of C and N were measured. The results obtained in this study indicated that dehydrogenase, arylsulfatase and N-mineralization activities demonstrated that there had been a recovery in soil microbial numbers, but provided no information on the influence of contaminants in soils. Microbial biomass C and N also presented an increase from 2002 to 2004, and soil organic matter and pH influenced the enzymatic activities, mainly dehydrogenase, acid phosphatase and arylsulfatase. An increase of microbial activities was observed in 2003, with several soil enzymes showing recoveries in their activities. Therefore, nutrient cycles have probably benefited from this, improving soil quality. [ABSTRACT FROM AUTHOR]

We used bioassays employing head capsule width and body length increase of Chironomus riparius larvae as end points to evaluate metal contamination in streams. Bioassays were performed in situ near an abandoned Portuguese goldmine in the spring of 2003 and 2004. Bioassays also were performed under laboratory conditions with water and sediment collected from each stream to verify if laboratory bioassays could detect in situ toxicity and to evaluate the relative contribution of sediment and water to overall toxicity. We used field sediments with control water and control sediments with field water to discriminate between metal contamination in water and sediment. Field water with dry and sieved, organic matter-free, and nontreated sediments was used to determine the toxicity of heavy metals that enter the organism through ingested material. In both in situ and laboratory bioassays, body length increase was significantly inhibited by metal contamination, whereas head capsule width was not affected. Body length increase was more affected by contaminated sediment compared to contaminated water. The lowest-effect level of heavy metals was observed in the dry and sieved sediment that prevented ingestion of sediment particles by larvae. These results suggest that body length increase of C. riparius larvae can be used to indicate the impact of metal contamination in rivers. Chironomus riparius larvae are more affected by heavy metals that enter the organism through ingested sediment than by heavy metals dissolved in the water column. Nevertheless, several factors, such as the particle size and organic matter of sediment, must be taken into account. [ABSTRACT FROM AUTHOR]