Range Of Environmental Sources Research Articles

Endocrine disrupting chemicals and breast cancer cells.

Many hundreds of endocrine disrupting chemicals (EDCs) have been measured as entering human breast tissue from a range of environmental sources, and this review focuses on discussion of mechanisms by which such EDCs may be contributing to the globally rising incidence of breast cancer. Many of the distinguishing features of breast cancer may be accounted for by EDC exposure, including, but not limited to, the fact that many EDCs possess estrogenic activity and exposure to estrogen is a main risk factor for breast cancer. Studies of the actions of EDCs in human breast cancer cells are aided by use of the conceptual framework of the hallmarks of cancer, and, acting by a variety of genomic and nongenomic mechanisms, EDCs have now been shown to enable all the hallmarks of cancer to develop in human breast cancer cells. Many studies report that hallmarks can develop at concentrations which are within the range of those measured in human breast tissues, especially when added as mixtures. The varied levels of different EDCs measured in individual breast tissue samples together with the overlapping and complementary mechanisms of action of the EDCs imply that thematic mechanisms will be driven inevitably by different chemical mixtures. Despite the complexity, EDCs do need to now be acknowledged as a risk factor for breast cancer in order for preventative strategies to include reduction in EDC exposure.

An improved primer set and amplification protocol with increased specificity and sensitivity targeting the Symbiodinium ITS2 region.

The Internal Transcribed Spacer 2 (ITS2) rRNA gene is a commonly targeted genetic marker to assess diversity of Symbiodinium, a dinoflagellate genus of algal endosymbionts that is pervasively associated with marine invertebrates, and notably reef-building corals. Here we tested three commonly used ITS2 primer pairs (SYM_VAR_5.8S2/SYM_VAR_REV, ITSintfor2/ITSReverse, and ITS-DINO/ITS2Rev2) with regard to amplification specificity and sensitivity towards Symbiodinium, as well as sub-genera taxonomic bias. We tested these primers over a range of sample types including three coral species, coral surrounding water, reef surface water, and open ocean water to assess their suitability for use in large-scale next generation sequencing projects and to develop a standardised PCR protocol. We found the SYM_VAR_5.8S2/SYM_VAR_REV primers to perform superior to the other tested ITS2 primers. We therefore used this primer pair to develop a standardised PCR protocol. To do this, we tested the effect of PCR-to-PCR variation, annealing temperature, cycle number, and different polymerase systems on the PCR efficacy. The Symbiodinium ITS2 PCR protocol developed here delivers improved specificity and sensitivity towards Symbiodinium with apparent minimal sub-genera taxonomic bias across all sample types. In particular, the protocol’s ability to amplify Symbiodinium from a range of environmental sources will facilitate the study of Symbiodinium populations across biomes.

Odorant receptor-mediated sperm activation in disease vector mosquitoes.

Insects, such as the malaria vector mosquito, Anopheles gambiae, depend upon chemoreceptors to respond to volatiles emitted from a range of environmental sources, most notably blood meal hosts and oviposition sites. A subset of peripheral signaling pathways involved in these insect chemosensory-dependent behaviors requires the activity of heteromeric odorant receptor (OR) ion channel complexes and ligands for numerous A. gambiae ORs (AgOrs) have been identified. Although AgOrs are expressed in nonhead appendages, studies characterizing potential AgOr function in nonolfactory tissues have not been conducted. In the present study, we explore the possibility that AgOrs mediate responses of spermatozoa to endogenous signaling molecules in A. gambiae. In addition to finding AgOr transcript expression in testes, we show that the OR coreceptor, AgOrco, is localized to the flagella of A. gambiae spermatozoa where Orco-specific agonists, antagonists, and other odorant ligands robustly activate flagella beating in an Orco-dependent process. We also demonstrate Orco expression and Orco-mediated activation of spermatozoa in the yellow fever mosquito, Aedes aegypti. Moreover, we find Orco localization in testes across distinct insect taxa and posit that OR-mediated responses in spermatozoa may represent a general characteristic of insect reproduction and an example of convergent evolution.

Differentiation ofFusarium spp. by Fourier Transform Infrared (FT-IR) spectroscopy

Fourier Transform Infrared (FT-IR) spectroscopy, in combination with chemometrics, was investigated as a simple method to differentiateFusarium spp. Strains were grown on solid culture plates for sporulation. Spectral data of spores ofFusarium spp. were recorded within the range from 4000 to 400 cm−1. Hierarchical cluster analysis (HCA) and principal components analysis (PCA) were used to study the clusters in the data of spectral regions of 3000–2800 and 1800–1480 cm−1. The virtual rate of correct differentiation (100%) was achieved for both the HCA and PCA. FT-IR technique shows high potential as a novel, accurate and easy-to-use differentiation method eagerly sought for the routine differentiation ofFusarium isolates from a wide range of environmental sources.

Morphological, Physiological, and Ethological Differences Between Walleye (Stizostedion vitreum vitreum) and Pikeperch (S. lucioperca)

A review of the literature indicated that pikeperch (Stizostedion lucioperca) are generally more tolerant than walleye (S. vitreum vitreum) of a wide range of environmental sources of stress, such as organic pollution, sedimentation, and fluctuating water levels. This advantage presumably arose from numerous morphological and physiological specializations which are expressed through appropriate behavioral patterns. Of prime importance is the ritualistic redd building and guarding behavior developed by the pikeperch which contributes to a consistently successful rate of fertilization and lowered mortality of their eggs and larvae. In addition, pikeperch have a much higher fecundity and require a less specific set of spawning conditions than do walleye. These attributes allow the pikeperch much greater reproductive success under stressful conditions and thus more flexibility in their range. Key words: behavior, cultural eutrophication, environmental stress, morphology, physiology, pikeperch, reproductive potential, reservoirs, Stizostedion, walleye