Shelter use and behaviour of juvenile Spotted Wolffish (<Emphasis Type="Italic">Anarhichas minor</Emphasis>) in an experimental context

Laboratory experiments were conducted to assess shelter use and behaviour of juvenile Spotted Wolffish, Anarhichas minor, using time-lapse video. Information about the behaviour of Spotted Wolffish and its habitat utilization is sparse due to the great depth at which this species lives. Four experiments were conducted using one or two fish per tank, with and without a shelter. The positions and movements of fish in the tanks and interactions between fish were monitored over 24-h periods. In experiments in which no shelter was available, Spotted Wolffish spent very little time exploring the water column. They did not show fidelity to a particular area on the bottom of the tank and exhibited few signs of aggressiveness to each other. When a shelter was made available, fish spent most of their time in the shelter or close to the shelter. The presence of a single shelter did not enhance aggressive behaviours in fish kept in pairs. When day and night observations were compared, no clear diel pattern emerged. The Canadian recovery plan for Spotted Wolffish calls for research aimed at describing their use of demersal habitats. The present study suggests that shelter availability might be an important feature of the habitat requirements of juvenile Spotted Wolffish.     

HIV-1 protease inhibitors containing statine: inhibitory potency and antiviral activity.

Several series of chemically different inhibitors of the HIV-1 aspartyl protease have been described. Nevertheless despite the high in vitro potency showed, in most cases these inhibitors are unable to inhibit viral replication in infected cells. Penetration of the inhibitors across the cell membrane might account for their low antiviral activity. The relationship between inhibitory potency, antiviral activity and chemical structures of a series of oligopeptides containing statine or statine derivatives are presented here.     

Functional and structural characterization of a thiol peroxidase from Mycobacterium tuberculosis

A thiol peroxidase (Tpx) from Mycobacterium tuberculosis was functionally analyzed. The enzyme shows NADPH-linked peroxidase activity using a thioredoxin-thioredoxin reductase system as electron donor, and anti-oxidant activity in a thiol-dependent metal-catalyzed oxidation system. It reduces H2O2, t-butyl hydroperoxide, and cumene hydroperoxide, and is inhibited by sulfhydryl reagents. Mutational studies revealed that the peroxidatic (Cys60) and resolving (Cys93) cysteine residues are critical amino acids for catalytic activity. The X-ray structure determined to a resolution of 1.75 A shows a thioredoxin fold similar to that of other peroxiredoxin family members. Superposition with structural homologues in oxidized and reduced forms indicates that the M. tuberculosis Tpx is a member of the atypical two-Cys peroxiredoxin family. In addition, the short distance that separates the Calpha atoms of Cys60 and Cys93 and the location of these cysteine residues in unstructured regions may indicate that the M. tuberculosis enzyme is oxidized, though the side-chain of Cys60 is poorly visible. It is solely in the reduced Streptococcus pneumoniae Tpx structure that both residues are part of two distinct helical segments. The M. tuberculosis Tpx is dimeric both in solution and in the crystal structure. Amino acid residues from both monomers delineate the active site pocket.     

Genistein and daidzein act on a panel of genes implicated in cell cycle and angiogenesis by Polymerase Chain Reaction arrays in human prostate cancer cell lines

Background: The prostate cancer most frequently affects men. The ethnic origin and family antecedents of prostate cancer are established as risk factors. The genetic factors associated with environmental factors such as the nutrition also play a role in the development of the cancer. Epidemiological studies showed that the Asian populations exhibited an incidence of prostate cancer markedly subordinate by comparison with the Western populations. This would be explained partially by their important consumption of soy. Both main phytoestrogens of soy, the genistein and the daidzein, present anti-proliferative properties. Methods: For that purpose, we used different prostate cancer cell lines (LNCaP, DU 145, PC-3) and, by flow cytometry, we determined the concentration of phytoestrogens inducing a cell cycle arrest and the required time of incubation. Results: Then, the effects of 40 μM genistein or 110 μM daidzein for 48 h were determined and studied on the expression of genes involved in the human cell cycle and angiogenesis and conducted by SYBR green quantitative PCR. Conclusion: We demonstrated modulations of cyclin-dependent kinase-related pathway genes, DNA damage-signaling pathway and a down-regulation of EGF and IGF.     

Development of an injectable composite for bone regeneration

With the development of minimally invasive surgical techniques, there is a growing interest in the research and development of injectable biomaterials especially for orthopedic applications. In a view to enhance the overall surgery benefits for the patient, the BIOSINJECT project aims at preparing a new generation of mineral-organic composites for bone regeneration exhibiting bioactivity, therapeutic activity and easiness of use to broaden the application domains of the actual bone mineral cements and propose an alternative strategy with regard to their poor resorbability, injectability difficulties and risk of infection. First, a physical-chemical study demonstrated the feasibility of self-setting injectable composites associating calcium carbonate-calcium phosphate cement and polysaccharides (tailor-made or commercial polymer) in the presence or not of an antibacterial agent within the composite formulation. Then, bone cell response and antimicrobial activity of the composite have been evaluated in vitro. Finally, in order to evaluate resorption rate and bone tissue response an animal study has been performed and the histological analysis is still in progress. These multidisciplinary and complementary studies led to promising results in a view of the industrial development of such composite for dental and orthopaedic applications.