Molecular responce of Atlantic cod's (Gadus morhua L.) cypia, prolactin and Zona radiata genes upon exposure to polychlorinated biphenyls

A molecular response study was conducted to determine whether Polychlorinated Biphenyl or PCB (Clophen A40) had an effect on the induction of the zona radiata, prolactin and cytochrome P4501A (CYP1A) mRNAs in matured Atlantic cod (Gadus morhua). A total of 127 fishes were maintained under natural photoperiod in tanks and fed with wet pellets containing Clophen A40. RNA samples were taken from the gonads, pituitary and the liver from day 0, 48 and 105 after sacrificing the fish and stored at -20OC prior to analysis. Analysis of gene induction by Northern hybridization assay showed the induction of prolactin and CYP1A in the pituitary and the liver tissues respectively after PCB treatment. The induction was found to be sex, age and seasonal specific. Males had greater gene expression than the females. There was however, no observed differences between the controlled and exposed fishes in terms of zona radiata gene expression. Although the picture is far from complete, the findings demonstrate the potential of using gene induction as a biomarker of aquatic pollution.Keywords: Cytochrome P4501A, Biomarker, Gene expressio

Spectral fluctuations of tridiagonal random matrices from the beta-Hermite ensemble

A time series delta(n), the fluctuation of the nth unfolded eigenvalue was recently characterized for the classical Gaussian ensembles of NxN random matrices (GOE, GUE, GSE). It is investigated here for the beta-Hermite ensemble as a function of beta (zero or positive) by Monte Carlo simulations. The fluctuation of delta(n) and the autocorrelation function vary logarithmically with n for any beta>0 (1<<n<<N). The simple logarithmic behavior reported for the higher-order moments of delta(n) for the GOE (beta=1) and the GUE (beta=2) is valid for any positive beta and is accounted for by Gaussian distributions whose variances depend linearly on ln(n). The 1/f noise previously demonstrated for delta(n) series of the three Gaussian ensembles, is characterized by wavelet analysis both as a function of beta and of N. When beta decreases from 1 to 0, for a given and large enough N, the evolution from a 1/f noise at beta=1 to a 1/f^2 noise at beta=0 is heterogeneous with a ~1/f^2 noise at the finest scales and a ~1/f noise at the coarsest ones. The range of scales in which a ~1/f^2 noise predominates grows progressively when beta decreases. Asymptotically, a 1/f^2 noise is found for beta=0 while a 1/f noise is the rule for beta positive.Comment: 35 pages, 10 figures, corresponding author: G. Le Cae

Accessing five- and seven-membered phosphorus-based heterocycles via cycloaddition reactions of azophosphines

Heterocycles containing both phosphorus and nitrogen have seen increasing use in recent years in luminescent materials, coordination chemistry and as building blocks for inorganic polymers, yet their chemistry is currently dominated by five- and six-membered derivatives. Seven-membered P/N heterocycles are comparatively scarce and lack general, high yielding syntheses. Here, we explore the synthesis and characterisation of 1,2,5-diazaphosphepines from azophosphines. The mechanism has been probed in detail with both computational and experimental studies supporting a stepwise mechanism to form a five-membered ring, and subsequent ring expansion to the diazaphosphepine. Regioselective synthesis of five- and seven-membered rings is possible using asymmetric alkynes. The Lewis acidic borane B(C6F5)3 could either catalyse the formation of the seven-membered ring (iPr derivative) or trap out a key intermediate via a frustrated Lewis pair (FLP) mechanism (tBu derivative)

Biokonsentrasi dan Bioakumulasi Mercury (Hg) Pada Lamun Enhalus Acoroides Di Teluk Kayeli Kabupaten Buru Provinsi Maluku

Gold reserves on Gunung Botak (Bald Mountain), Buru Island, were discovered in 2011. Since then, thousands of illegal miners have used amalgamation methods to extract gold in the areas of Gunung Botak and Gogrea, Buru Island. The resulting waste is disposed of into the environment directly without any treatment process so it is very dangerous for humans and the environment. This research was conducted to determine the ability of the Enhalus acoroides type of seagrass to accumulate heavy metal mercury (Hg) in the aquatic environment. This research shows that the heavy metal mercury has been distributed in the water sediments along Kayeli Bay. Mercury bio-concentration (accumulation) Gunung Botak, Kayeli Bay, Mercury (Hg), bioconcenstration, Seagrass, Enhalus acoroides, Kayeli Baywas found in Enhalus acoroides seagrass, in leaves (0.0243-0.0373 mg/Kg), and in rhizomes (0.0453-0.0663 mg/Kg). This result shows that the Kayeli Bay ecosystem has been contaminated with mercury

A three-dimensional model of the human blood-brain barrier to analyse the transport of nanoparticles and astrocyte/endothelial interactions [version 1; referees: 2 approved with reservations]

The aim of this study was to develop a three-dimensional (3D) model of the human blood-brain barrier in vitro, which mimics the cellular architecture of the CNS and could be used to analyse the delivery of nanoparticles to cells of the CNS. The model includes human astrocytes set in a collagen gel, which is overlaid by a monolayer of human brain endothelium (hCMEC/D3 cell line). The model was characterised by transmission electron microscopy (TEM), immunofluorescence microscopy and flow cytometry. A collagenase digestion method could recover the two cell types separately at 92-96% purity. Astrocytes grown in the gel matrix do not divide and they have reduced expression of aquaporin-4 and the endothelin receptor, type B compared to two-dimensional cultures, but maintain their expression of glial fibrillary acidic protein. The effects of conditioned media from these astrocytes on the barrier phenotype of the endothelium was compared with media from astrocytes grown conventionally on a two-dimensional (2D) substratum. Both induce the expression of tight junction proteins zonula occludens-1 and claudin-5 in hCMEC/D3 cells, but there was no difference between the induced expression levels by the two media. The model has been used to assess the transport of glucose-coated 4nm gold nanoparticles and for leukocyte migration. TEM was used to trace and quantitate the movement of the nanoparticles across the endothelium and into the astrocytes. This blood-brain barrier model is very suitable for assessing delivery of nanoparticles and larger biomolecules to cells of the CNS, following transport across the endothelium

A cyclic peptide inhibitor of HIF-1 heterodimerization that inhibits hypoxia signaling in cancer cells

Hypoxia inducible factor-1 (HIF-1) is a heterodimeric transcription factor that acts as the master regulator of cellular response to reduced oxygen levels, thus playing a key role in the adaptation, survival and progression of tumors. Here we report cyclo-CLLFVY, identified from a library of 3.2 million cyclic hexapeptides using a genetically encoded high-throughput screening platform, as an inhibitor of the HIF-1α/HIF-1β protein-protein interaction in vitro and in cells. The identified compound inhibits HIF-1 dimerization and transcription activity by binding to the PAS-B domain of HIF-1α, reducing HIF-1-mediated hypoxia response signaling in a variety of cell lines, without affecting the function of the closely related HIF-2 isoform. The reported cyclic peptide demonstrates the utility of our high-throughput screening platform for the identification of protein-protein interaction inhibitors, and forms the starting point for the development of HIF-1 targeted cancer therapeutics

Dual, Photo‐Responsive and Redox‐Active Supramolecular Foldamers

We report on dual, light‐responsive and redox‐active foldamers that demonstrate reversible and robust stimuli‐induced behaviour. Herein, UV/Vis, 1H NMR and circular dichroism (CD) spectroscopy and cyclic voltammetry have been used to establish the reversibility and highly robust nature of the light‐ and redox‐driven behaviour of these new foldamers with minimal levels of fatigue observed even upon multiple cyclic treatments with irradiative/non‐irradiative and oxidative/reductive conditions. This proof‐of‐concept work paves the way towards the creation of novel stimuli‐responsive foldamers of increasing sophistication capable of demonstrating reversible and robust responses to multiple distinct stimuli

Dual, Photo‐Responsive and Redox‐Active Supramolecular Foldamers

We report on dual, light‐responsive and redox‐active foldamers that demonstrate reversible and robust stimuli‐induced behaviour. Herein, UV/Vis, 1H NMR and circular dichroism (CD) spectroscopy and cyclic voltammetry have been used to establish the reversibility and highly robust nature of the light‐ and redox‐driven behaviour of these new foldamers with minimal levels of fatigue observed even upon multiple cyclic treatments with irradiative/non‐irradiative and oxidative/reductive conditions. This proof‐of‐concept work paves the way towards the creation of novel stimuli‐responsive foldamers of increasing sophistication capable of demonstrating reversible and robust responses to multiple distinct stimuli