René Bennes

Identification of new proteins in follicular fluid of mature human follicles

Proteins present in human follicular fluid (HFF) have been poorly characterized to date. The purpose of our study was to analyse the protein content and identify new proteins originating from fluid of mature human follicles. A total of six females from infertile couples referred for in vitro fertilization (IVF) were stimulated and 44 follicular fluid samples from mature follicles yielding an oocyte were collected 34–36 h after human chorionic gonadotropin administration. HFF samples were processed for high‐resolution two‐dimensional polyacrylamide gel electrophoresis (2‐D PAGE). Comparative analysis of the 2‐D gels revealed up to 600 spots, of which four were selected because of variations in their expression level. Using direct sequencing procedures (Edman degradation) or matrix assisted laser desorption/ionization‐mass spectrometry (MALDI‐MS), these four spots were identified as three new proteins: thioredoxin peroxydase 1 (TDPX1), transthyretin (TTR) and retinol‐binding protein (RBP). The proteins identified here may emerge as potential candidates for specific functions during folliculogenesis and may prove useful as biomedical markers for follicle and/or oocyte maturation.

Evidence for aggregation of endothelin 1 in water

In this report it is shown by CD spectroscopy that endothelin 1, when dissolved in water, is able to present intermolecular interactions leading to formation of aggregates. Surface tension and conductivity measurements suggest that the aggregation occurs through formation of micelles with a CMC of about 2.2 × 10−5 M.

The adsorption of quaternary ammonium salts at a mercury solution interface: Part II. Non-symmetrical quaternary ammonium salts

Abstract The adsorption of triethyl alkyl (and allyl) ammonium bromides on a mercury electrode has been investigated. The isotherms and values of the free energy of adsorption yield information on the mode of adsorption of the cations. The formation of partial bimolecular films on the surface of mercury by the cations studied has been described and a simple explanation put forward concerning the mechanism of destruction of these films.

High performance two-dimensional gel electrophoresis using a wetting agent Tergitol® NP7

Two‐dimensional electrophoresis is an efficient method for the analysis of a broad range of complex protein samples. Current two‐dimensional gel techniques are not suited for analysis of the small amount of proteins from tissue samples in the presence of high concentration of salts. Here we describe an improved two‐dimensional gel electrophoresis procedure based on the use of a nonionic wetting agent, Tergitol® NP7, in rehydration solution combined with the application of a linear potential sweep during isoelectrofocusing. This experimental approach yields a dramatic increase in the resolution and focusing of proteins visualized on two‐dimensional gels. This technique is less time‐consuming and laborious than the current techniques and can be used for a variety of two‐dimensional electrophoresis applications, including proteome analysis.

Surface transitions in binary liquid mixtures

Abstract Using a reasoning based on the classical thermodynamics of adsorption, the occurrence of a surface transition is described in terms of a phase diagram. The surfaces involved are the liquid-vapor and liquid-solid interfaces, when only physisorption takes place. Cahns conclusion concerning the existence of a prewetting line in the monophasic zone of the phase diagram of the binary system has been verified. Two experimental examples have been considered, viz., the methanol-cyclohexane and water-2-butoxyethanol systems.

Conditions of phase separation, both at the interface (occasionally considered as a monolayer) and in solution for a binary liquid vapor system: The adsorption isotherm and the consequences of critical phenomena on the behavior of the system

Abstract The effects of modifications in the bulk and superficial phases of a binary mixture in equilibrium with its vapor, on the form of the surface adsorption isotherm, have been studied, and in particular the influence of deviations from ideality and of temperature. One observes, according to the value of the latter as compared to the critical temperatures of the surface and in the solution that a phase separation is possible, which may lead to a system evolving in a different manner from one simply separating into two phases. The monolayer model was used in a part of the work to describe the surface phase.

Wetting transitions and other wetting properties of water–2,5 lutidine system

The wetting behavior of the water–2,5 lutidine system has been studied around the lower consolute point (Tc=13.1 °C). We have measured contact angles and surface tensions by varying the concentration and temperature. In the diphasic region, a wetting transition has been observed at 46–47 °C on a silica wall by direct observation of the solid–liquid–liquid contact angle. The perfect wetting occurs close to Tc, the wetting phase is water rich. At the liquid–vapor interface, the analysis of the values of the surface tensions shows that, close to Tc, they obey critical laws and that a lutidine rich phase perfectly wets the vapor and the water rich phase. These behaviors have been analyzed on the basis of the contact angles of the monophasic on a silica wall on both sides of the coexistence curve, and the general variation of the surface tensions. A second wetting transition has been shown on a differently washed glass surface. Reference is made to the theoretical and experimental works following the early wor...

Single channels and surface potential of linear gramicidins.

The single channel data for 4 different linear gramicidins containing either 4 Trp, 4 Phe, 4 Tyr or TyrBzl have been analyzed on the basis of 3 barriers-2 sites model. They form 2 families which differ by their single channel behavior and thus different energy profiles of the channel. A relationship between the surface potential and the entry barrier is proposed.

Universal amplitude ratios of surface tensions near a critical point in a liquid binary system: Water‐2,5 lutidine

Experimental data of surface tensions along the critical isochore (1) and the two branches of the coexistence curve (2,3) for the water‐2,5 lutidine system have been used in order to check signs and values of the universal amplitude ratios of the critical laws in the forms σα,j=σc+A(T−Tc)+Bj(T−Tc)μ, j=1,2,3, with imposed μ=1.26. A and the Bj’s being highly correlated, several statistical tests using the values of the ratios have been used. Experimental values are compatible with P+=B/Bi=−0.59 (B: isochore; Bi: interfacial tension in the two phases system), maybe with Q=B/B‘=−0.83 (B‘ one branch of the coexistence curve) and certainly with its sign. The other ratios cannot be verified at all by the experimental data.

Adsorption of alcohols at an air—solution interface: A pseudoregular monolayer model

Abstract A monolayer model of constant thickness has been utilized to explain the adsorption of n -propanol, t-butanol, s-butanol, and n -butanol at an air—aqueous solution interface. Two coefficients the one B σ , characterizing the interfacial properties and the other B σ those of the bulk solution have been correlated. Attention is drawn to the relation between B σ and the hydration of the alcohol molecules in solution.