Proteomic analysis of the Plasmodium male gamete reveals the key role for glycolysis in flagellar motility.

BACKGROUND: Gametogenesis and fertilization play crucial roles in malaria transmission. While male gametes are thought to be amongst the simplest eukaryotic cells and are proven targets of transmission blocking immunity, little is known about their molecular organization. For example, the pathway of energy metabolism that power motility, a feature that facilitates gamete encounter and fertilization, is unknown. METHODS: Plasmodium berghei microgametes were purified and analysed by whole-cell proteomic analysis for the first time. Data are available via ProteomeXchange with identifier PXD001163. RESULTS: 615 proteins were recovered, they included all male gamete proteins described thus far. Amongst them were the 11 enzymes of the glycolytic pathway. The hexose transporter was localized to the gamete plasma membrane and it was shown that microgamete motility can be suppressed effectively by inhibitors of this transporter and of the glycolytic pathway. CONCLUSIONS: This study describes the first whole-cell proteomic analysis of the malaria male gamete. It identifies glycolysis as the likely exclusive source of energy for flagellar beat, and provides new insights in original features of Plasmodium flagellar organization

Improving Hang-Glider Maneuvrability using Multiple Winglets: A Numerical and Experimental Investigation

The main aim of the present paper is to investigate the influence of multiple winglets on hang-glider climbing performance. The study aims to optimize the CL3/2/CD parameter. The investigation was performed both numerically and experimentally starting from airfoils and winglet shape design. Given the shape of a real hang-glider wing under aerodynamic load the first phase of the work concerned the main geometric characteristics of winglet design : number of winglets, airfoils, planform shape, twist. A 3D wing model was built and using the indications obtained from the design, different sets of winglets were built. The wing model was built to enable winglets to be applied to the wing tip without changing the wing span and aspect ratio. The tests carried out on the hang glider model showed an improvement in wing performance of about 15%. However, the model reproduced a full scale wing flying under aerodynamic load and, according to the model builders, it showed a positive twist angle (leading edge up). This could mean that the winglets were more efficient because the original wing showed a strong tip vortex. A new model wing with an elliptical planform was therefore built to verify this further. The test results on the elliptical wing did not show the same improvement in performance obtained with the hang glider model. Nevertheless, compared to the original elliptical wing an improvement was still found

Perturbations produced by electrospray ionization mass spectrometry in the speciation of aluminium(III)/1,6-dimethy1-4-hydroxy-3-pyridinecarboxylate aqueous solutions

Electrospray ionization mass spectrometry (ESI-MS) is very often employed to study metal/ligand equilibria in aqueous solution. However, the ionization process can introduce perturbations whichaffect the speciation results in an unpredictable way. It is necessary to identify these perturbations in order to correctly interpret the ESI-MS speciation results. Aluminium(III)/1,6-dimethyl-4-hydroxy-3-pyridinecarboxylate (DQ716) aqueous solutions at various pH were analysed by ESI-MS, and speciation results were compared with those obtained by equilibrium techniques. Differences observed were both qualitative and quantitative. The ESIMS spectral changes due to different settings of the following instrumental parameters were analyzed: the solution flow rate (FS), the nebulizer gas flow rate (FG), the potential applied at the entrance capillary (EC), and the temperature of the drying gas (TG). The effects produced by FS and EC on the spectra strongly suggest the key role of surface activity in determining the relative fraction of the ions reaching the detector. The experimental effects of FS and TG were interpreted considering the presence of at least two reactions in the gas phase and a dimerization occurring in the droplets. These perturbations cannot be generalized because they appear to be chemical system-related and instrument-dependent. Therefore, the identification of perturbations is a required task for any metal-ligand equilibrium study performed by ESI-MS. Our results indicate that perturbations can be identified by evaluating the effects produced in the spectra by a change of instrumental parameters

Heat and mass transfer scale-up issues during freeze-drying, I: Atypical radiation and the edge vial effect

The aim of this study is to determine whether radiation heat transfer is responsible for the position dependence of heat transfer known as the edge vial effect. Freeze drying was performed on a laboratory-scale freeze dryer using pure water with vials that were fully stoppered but had precision cut metal tubes inserted in them to ensure uniformity in resistance to vapor flow. Sublimation rates were determined gravimetrically. Vials were sputter-coated with gold and placed at selected positions on the shelf. Average sublimation rates were determined for vials located at the front, side, and center of an array of vials. Sublimation rates were also determined with and without the use of aluminum foil as a radiation shield. The effect of the guardrail material and its contribution to the edge vial effect by conduction heat transfer was studied by replacing the stainless steel band with a low-thermal conductivity material (styrofoam). The emissivities (ε) of relevant surfaces were measured using an infrared thermometer. Sublimation rate experiments were also conducted with vials suspended off the shelf to study the role of convection heat transfer. It was found that sublimation rates were significantly higher for vials located in the front compared to vials in the center. Additional radiation shields in the form of aluminum foil on the inside door resulted in a decrease in sublimation rates for the front vials and to a lesser extent, the center vials. There was a significant decrease in sublimation rate for goldcoated vials (ε≈0.4) placed at the front of an array when compared to that of clear vials (ε≈0.9). In the case of experiments with vials suspended off the shelf, the heat transfer coefficient was found to be independent of chamber pressure, indicating that pure convection plays no significant role in heat transfer. Higher sublimation rates were observed when the steel band was used instead of Styrofoam while the highest sublimation rates were obtained in the absence of the guardrail, indicating that the metal band can act as a thermal shield but also transmits some heat from the shelf via conduction and radiation. Atypical radiation heat transfer is responsible for higher sublimation rates for vials located at the front and side of an array. However, the guardrail contributes a little to heat transfer by conduction