Evaluation of zona pellucida birefringence intensity during in vitro maturation of oocytes from stimulated cycles

Background: This study evaluated whether there is a relationship between the zona pellucida birefringence (ZP-BF) intensity and the nuclear (NM) and cytoplasmic (CM) in vitro maturation of human oocytes from stimulated cycles.Results: The ZP-BF was evaluated under an inverted microscope with a polarizing optical system and was scored as high/positive (when the ZP image presented a uniform and intense birefringence) or low/negative (when the image presented moderate and heterogeneous birefringence). CM was analyzed by evaluating the distribution of cortical granules (CGs) throughout the ooplasm by immunofluorescence staining. CM was classified as: complete, when CG was localized in the periphery; incomplete, when oocytes presented a cluster of CGs in the center; or in transition, when oocytes had both in clusters throughout cytoplasm and distributed in a layer in the cytoplasm periphery Nuclear maturation: From a total of 83 germinal vesicle (GV) stage oocytes, 58 of oocytes (69.9%) reached NM at the metaphase II stage. From these 58 oocytes matured in vitro, the high/positively scoring ZP-BF was presented in 82.7% of oocytes at the GV stage, in 75.8% of oocytes when at the metaphase I, and in 82.7% when oocytes reached MII. No relationship was observed between NM and ZP-BF positive/negative scores (P = 0.55). These variables had a low Pearson's correlation coefficient (r = 0.081). Cytoplasmic maturation: A total of 85 in vitro-matured MII oocytes were fixed for CM evaluation. Forty-nine oocytes of them (57.6%) showed the complete CM, 30 (61.2%) presented a high/positively scoring ZP-BF and 19 (38.8%) had a low/negatively scoring ZP-BF. From 36 oocytes (42.3%) with incomplete CM, 18 (50%) presented a high/positively scoring ZPBF and 18 (50%) had a low/negatively scoring ZP-BF. No relationship was observed between CM and ZP-BF positive/negative scores (P = 0.42). These variables had a low Pearson's correlation coefficient (r = 0.11).Conclusions: The current study demonstrated an absence of relationship between ZP-BF high/positive or low/negative score and nuclear and cytoplasmic in vitro maturation of oocytes from stimulation cycles

EHPC 2010: Sharing knowledge on environmental health for risk mitigation

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Implementing a Restoration Program for the Endangered White Abalone (Haliotis sorenseni) in California

A restoration program including wild population surveys, captive breeding, health monitoring, recovery site preparation, and recovery modeling has been implemented to restore white abalone (Haliotis sorenseni) populations in California. White abalone once supported a lucrative fishery and are now endangered, nearing extinction at less than 1% of baseline abundances. Recent deep water surveys indicate that populations continue to decline with no signs of recruitment, despite the closure of the fishery in 1996. Four sites with artificial reefs (n=12/site) in optimal white abalone habitat were established. No wild white abalone have been found at these sites. Captive abalone were spawned in the spring of each year from 2012 to 2015. Each year, the production of 1-y-old abalone has increased in the captive breeding program from approximately 20 in 2012, to 150 in 2013 and an estimated 2,000 in 2014. In 2015, the breeding program reached two milestones: (1) most successful spawning season to date and (2) the hatchery distributed 200 captive-reared abalone to 4 partner institutions within the White Abalone Recovery Consortium (WARC). The WARC is made up of federal and state agencies, universities, public aquaria, and aquaculture organizations, all committed to white abalone restoration. The next steps for the program include expanding the captive breeding program to increase production, monitoring abalone health and genetic diversity, and conducting stocking studies to enhance growth and survival in the ocean. The goal of the stocking program is to create a reproductive population in the wild to bring white abalone back from the brink of extinction

Comparative environmental fate and toxicity of copper nanomaterials

Given increasing use of copper-based nanomaterials, particularly in applications with direct release, it is imperative to understand their human and ecological risks. A comprehensive and systematic approach was used to determine toxicity and fate of several Cu nanoparticles (Cu NPs). When used as pesticides in agriculture, Cu NPs effectively control pests. However, even at low (5–20 mg Cu/plant) doses, there are metabolic effects due to the accumulation of Cu and generation of reactive oxygen species (ROS). Embedded in antifouling paints, Cu NPs are released as dissolved Cu+ 2 and in nano- and micron-scale particles. Once released, Cu NPs can rapidly (hours to weeks) oxidize, dissolve, and form CuS and other insoluble Cu compounds, depending on water chemistry (e.g. salinity, alkalinity, organic matter content, presence of sulfide and other complexing ions). More than 95% of Cu released into the environment will enter soil and aquatic sediments, where it may accumulate to potentially toxic levels (> 50–500 μg/L). Toxicity of Cu compounds was generally ranked by high throughput assays as: Cu+ 2 > nano Cu(0) > nano Cu(OH)2 > nano CuO > micron-scale Cu compounds. In addition to ROS generation, Cu NPs can damage DNA plasmids and affect embryo hatching enzymes. Toxic effects are observed at much lower concentrations for aquatic organisms, particularly freshwater daphnids and marine amphipods, than for terrestrial organisms. This knowledge will serve to predict environmental risks, assess impacts, and develop approaches to mitigate harm while promoting beneficial uses of Cu NPs

Combining Electrophoretic and Fluorescence Method for Screening Fine Structural Variations Among Lignin Model Polymers Differing in Monomer Composition

Due to the challenges of cell walls (biomass) and its applications in various new technologies, there is a need of rapid and reliable screening of fine variations in lignin structure. The in vitro synthesized lignin model polymers are good experimental system to relate lignin structure/properties with its applications. We used iso-electric focusing electrophoresis (IEF) and fluorescence spectroscopy for screening fine structural variations in lignin model polymers, synthesized from the three lignin monomers, coniferyl alcohol, ferulic acid and p-coumaric acid, mixed in various ratios. The results were related with the thermal behavior of the polymers, revealed by differential scanning calorimetry. Each polymer had characteristic IEF pattern that can be used as its fingerprint. On the basis of the number and intensity of particular bands, it is possible to detect fine differences between polymer patterns, associated with the charge distribution on the polymer fractions. The blue shift of the main fluorescence maximum position of the polymers increased in the same order as temperature of glass transition, i. e. (polymer from coniferyl alcohol)>[polymer from coniferyl alcohol and ferulic acid 9: 1 (w/w)>[(polymer from coniferyl alcohol, ferulic acid and p-coumaric acid 8: 1: 1)>(polymer from coniferyl alcohol and p-coumaric acid 9: 1). The results show that the proposed combination of the fluorescence method and IEF may be used to gain complementary information on fine structural differences among the polymers, and influence of the types and ratios of the monomers building the polymer structure