An in vivo multiwell-based fluorescent screen for monitoring vertebrate thyroid hormone disruption

There is a pressing need for high throughput methods to assess potential effects of endocrine disrupting chemicals (EDCs). released into the environment. Currently our ability to identify effects in vitro exceeds that for in vivo monitoring. However, only in vivo analysis provides the full spectrum of physiological impacts exerted by a given chemical. With the aim of finding a physiological system compatible with automatic plate reading we tested the capacity of early embryonic stage Xenopus laevis tadpoles to monitor thyroid hormone (TH) disruption. Fluorescent transgenic X. laevis embryos bearing a TH/bZIP-eGFP construct, placed in 96 well plates, were used for a physiological-based screen for potential TH signaling disruptors. Using stage NF-45 embryos (time of thyroid gland formation) allowed rapid detection of chemical interference with both peripheral TR signaling and production of endogenous TH. Nanomolar concentrations of TH receptor agonists could be detected within 72 h. Moreover, when testing against a 5nM T3 challenge, the effects of inhibitors of TH production were revealed, including inhibitors of TH synthesis, (methimazole: 1 mM or sodium perchlorate: 3.56 microM), as well as antagonists acting at the receptor level (NH3: 2 microM) and a deiodinase inhibitor (iopanoic acid: 10 microM). Finally, we show that the thyroid disrupting activities of BPA (10 microM) and TBBPA (1 microM) can also be detected in this rapid screening protocol. Finally, this noninvasive technology using an automatic reading system shows low variability (around 5%) and permits detection of subtle changes in signaling by EDCs that either inhibit or activate TH signaling in vivo.     

Polyphasic characterization of Aspergillus section Flavi isolated from animal feeds in Algeria

In Algeria, little information is available on the population structure of Aspergillus section Flavi in raw materials and resultant animal feeds. A total of 172 isolates belonging to Aspergillus section Flavi were recovered from 57 animal feeds and identified on the basis of macro and micro-morphological characters, mycotoxin production and genetic relatedness. For the molecular analysis, sequencing of the calmodulin gene (CaM) and the internal transcribed spacer (ITS) regions were performed for representative isolates. Four distinct morphotypes were distinguished: Aspergillus flavus (78.5%), Aspergillus tamarii (19.2%), Aspergillus parasiticus (1.7%), and Aspergillus alliaceus (0.6%). All A. flavus isolates were of the L type and no correlation between sclerotia production and aflatoxigenicity was observed. Our results showed that 68% of the A. flavus strains produced aflatoxins B (AFB), and 72.7% were cyclopiazonic acid (CPA) producers. The three isolates of A. parasiticus were able to produce AFB and aflatoxins G but not CPA whereas, all the strains of A. tamarii produced only CPA. The obtained results revealed the presence of different species of Aspergillus section Flavi, among which were aflatoxin producers. This study provides evidence useful for considerations in aflatoxin control strategies.     

Identification of Lactic Acid Bacteria from Algerian Traditional Cheese,El-Klila

The lactic acid bacteria from dried El-Klila, an Algerian traditional cheese were studied, The cheese was also examined for chemical and physical characteristics. The isolated strains from sample K1 belonged to Enterococcus faecalis , Enterococcus faecium , Lactobacillus confusus and Streptococcus sp. Enterococci were the most frequently found. However, the isolates from sample K3 were identified as Pediococcus sp, Pediococcus acidilactici , Lactobacillus sp, Streptococcus sp and Leuconostoc sp. Pediococci were the predominant strains. The samples had high protein content (538·5 g kg⁻¹ for K1 and 549·8 g kg⁻¹ for K3) and considered as extra-hard cheese.     

Effects of trace metal elements on ultrastructural features of hepatopancreas of Armadillidium granulatum Brandt, 1833 (Crustacea,Isopoda)

This study was conducted to compare metals bioaccumulation in the terrestrial isopod Armadillidium granulatum collected from Ghar El Melh lagoon. We focused on recognizing the effects of trace elements on hepatopancreas functional role. To this end, isopod specimens were exposed for 3 weeks to sediments contaminated with cadmium, copper, zinc, mercury, and nickel. Three concentrations were used in duplicate for each experimental condition. At the end of the experiment, metal body burdens were determined using flame atomic absorption spectrometry. Results of the bioaccumulation factor (BAF) showed that the species A. granulatum was classified as a Cu macroconcentrator (BAF > 2) and a Zn deconcentrator (BAF < 2). Dose dependent morphological and histological changes were observed in the hepatopancreas cells using transmission electron microscopy. The predominant features were: microvillus border disruption, condensation of the cytoplasm with increasing endoplasmic reticulum, mitochondria, lysosomes and granules that accumulated metals in B and S cells. The number of lipid droplets decreased especially after Cd, Zn, Hg, and Ni treatments. This study demonstrated that the terrestrial isopod A. gramulatum could be a good indicator of soil metal contamination.     

A Primal-Dual algorithm for nonnegative N-th order CP tensor decomposition: application to fluorescence spectroscopy data analysis

Multidimensional Systems and Signal Processing - This work concerns the resolution of inverse problems encountered in multidimensional signal processing problems. Here, we address the problem of...     

Physiological and histopathological responses of Porcellio laevis (Isopoda,Crustacea) as indicators of metal trace element contamination

This study was designed to assess the impact of the mixture of cadmium (Cd) and zinc (Zn) on the bioaccumulation and the ultrastructural changes in the hepatopancreas of Porcellio laevis (Latreille, 1804) after 4 weeks of exposure to contaminated Quercus leaves under laboratory conditions. For each metal, four concentrations were used with four replicates for each concentration. Metal concentrations in the hepatopancreas and the rest of the body were determined using atomic absorption spectrometry. From the first week until the end of the experiment, a weight gain in P. laevis was observed particularly between the first and the end of exposure from 93.3 ± 18.22 mg fw to 105.22 ± 16.16 mg fw and from 106.4 ± 22.67 mg fw to 125.9 ± 23.9 mg fw for Mix1 and Mix4, respectively. Additionally, the determined metal trace elements (MTE) concentrations in the hepatopancreas were considerably higher compared to those in the rest of the body and seem to be dose‐dependent. Using transmission electron microscopy (TEM), some alterations were highlighted in the hepatopancreas. The main observed alterations were (a) the destruction of the microvilli border in a considerable portion of cells, (b) the increase of the lipid droplets with different shapes and sizes, (c) the increase in the number of the mitochondria, and (d) the appearance of TE in the form of B‐type granules. The obtained results confirmed the ability of P. laevis to deal with high amounts of MTE, suggesting its possible use in future soil's biomonitoring programs.     

Antibacterial peptides from barbel muscle protein hydrolysates: Activity against some pathogenic bacteria

Peptides obtained by enzymatic hydrolysis of fish proteins exhibit not only nutritional but also biological properties of dietary uses, or even therapeutic potential. The objective of the present study was to isolate and characterize peptides from the protein hydrolysates of barbel muscle with antibacterial activity against Gram-positive (Listeria monocytogenes, Staphylococcus aureus, Enterococcus faecalis, Micrococcus luteus and Bacillus cereus) and Gram-negative (Escherichia coli, Salmonella enterica, Pseudomonas aeruginosa, Klebsiella pneumoniae and Enterobacter sp.) bacteria. Barbel muscle protein hydrolysates (BMPHs), obtained by treatment with Alcalase^® (DH = 6.6%), was fractionated by size exclusion chromatography on a Sephadex G-25 and purified by reversed-phase high performance liquid chromatography (RP-HPLC). The molecular masses and amino acid sequences of these peptides were determined using ESI–MS and ESI–MS/MS, respectively. Eleven peptides in F_II-1, F_II-2, F_II-3 and F_II-4 sub-fractions separated by RP-HPLC were identified. The most active peptide fraction (F_II-3) contained three peptides: Ala–Ala–Ala–Leu; Ala–Ala–Gly–Gly–Val and Ala–Ala–Val–Lys–Met.     

Preparation process and properties of LiCoO2/PANI/dodecylbenzenesulfonate composite electrode materials

Composite materials that combine the lithium exchanging material LiCoO₂ and the conductive polymer poly(aniline) (PANI) have been investigated regarding their possible application to electrode materials of lithium batteries. Such composite materials have been prepared by means of polymerization of aniline in acidic suspensions of LiCoO₂ particles. PANI was synthesized by oxidative polymerization of aniline by ammonium persulfate in the presence of sodium dodecylbenzenesulfonate (SDBS) as a micellar template and dopant. The composite material consisted in LiCoO₂ particles dispersed in a continuous matrix of PANI. The ribbon-like morphology of the powdered material was distinctly different of the morphologies of the parent materials. The conductive material had conductivity close to that of PANI because the LiCoO₂ content of the composite material was low. The presence of the poorly conductive inorganic phase caused a significant loss of conductivity, showing that LiCoO₂ blocked electronic transfers between PANI crystallites. Ammonium persulfate caused the loss of lithium from LiCoO₂ when it was used at high concentration in the polymerization recipe. In this case a new phase made of Co₃O₄ formed by chemical decomposition of Li_xCoO₂. Thin films prepared from stable suspensions of composite materials in water show comparable electrical performance to that measured for bulk materials.     

Preparation, structure and infrared spectrum of NaEuP2O7

Crystals of NaEuP₂O₇ have been grown by the flux technique and characterized by X-ray diffraction. Single crystal structure of NaEuP₂O₇ has been solved, for the first time; it crystallizes in the monoclinic P2₁/n space group with lattice parameters : a = 5.238(2), b = 8.443(4), c = 12.486(6) Å, β = 91.404°(2), V = 552.0(4) ų, Z = 4. The crystal structure has been refined yielding a final R(F²) =0.049 and R_w(F²) = 0.138 for 1313 independent reflections (F_o² ≥ 2σ(F_o²)). In this structure, the PO₄ tetrahedral are linked by bridging oxygen to give P₂O₇ groups, these groups are connected to the EuO₈ polyhedron by sharing two oxygen corners to form three-dimensional framework in which channels are noticed and where the sodium ions are located. The frequencies of the vibrational modes of the crystal were obtained from measurements of the infrared spectra.