The protozoan intestinal parasite Entamoeba histolytica infects millions of people worldwide and is capable of causing amebic dysentery and amebic liver abscess. The closely related species Entamoeba dispar colonizes many more individuals, but this organism does not induce disease. To identify molecular differences between these two organisms that may account for their differential ability to cause disease in humans, we used two-dimensional gel-based (DIGE) proteomic analysis to compare whole cell lysates of E. histolytica and E. dispar. We observed 141 spots expressed at a substantially (>5-fold) higher level in E. histolytica HM-1∶IMSS than E. dispar and 189 spots showing the opposite pattern. Strikingly, 3 of 4 proteins consistently identified as different at a greater than 5-fold level between E. histolytica HM-1∶IMSS and E. dispar were identical to proteins recently identified as differentially expressed between E. histolytica HM-1∶IMSS and the reduced virulence strain E. histolytica Rahman. One of these was E. histolytica alcohol dehydrogenase 3 (EhADH3). We found that E. histolytica possesses a higher level of NADP-dependent alcohol dehydrogenase activity than E. dispar and that some EhADH3 can be localized to the surface of E. histolytica. Episomal overexpression of EhADH3 in E. histolytica trophozoites resulted in only subtle phenotypic differences in E. histolytica virulence in animal models of amebic colitis and amebic liver abscess, making it difficult to directly link EhADH3 levels to virulence differences between E. histolytica and less-pathogenic Entamoeba.

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Leucine rich repeats serve as recognition motifs for surface proteins from bacteria and eukaryotes. The BspA protein from Bacteroides forsythus mediates bacterial binding to fibronectin and contains leucine rich repeats of the Treponema pallidum (TpLRRP) family. Here we show that the protozoan parasite Entamoeba histolytica contains multiple BspA-like proteins, including a family of surface proteins which possess a new form of a leucine rich repeat that differs from the standard Treponema pallidum-like leucine rich repeat (TpLRRP) by possessing two conserved cysteine residues.

TB17 is an ultra-high-strength titanium alloy, a material typically difficult to machine. The surface quality and integrity of titanium alloy TB17 are poor after machining, which can seriously affect its service performance and restrict its fields of application. Therefore, the optimization of high-speed milling process parameters for the new ultra-high-strength titanium alloy TB17 was investigated based on multiple performance characteristics, including surface roughness, surface microhardness, and surface residual stress. The Taguchi method with grey relational analysis was utilized for the experiments. Additionally, analysis of variance was employed to evaluate the most influential factors for surface integrity in the high-speed milling of titanium alloy TB17. The results of the analysis using the Taguchi-Grey relational analysis method indicate that the preferred combination of high-speed milling process parameters are as follows: the cutting fluid condition of H-1 fine grinding fluid, using a milling speed of 100 m/min, a feed per tooth of 0.02 mm/z, an axial depth of cut of 1 mm, a radial depth of cut of l.5 mm, a rake angle of 18°, a clearance angle of 12°, and a helix angle of 60°. Moreover, the analysis of variance reveals that milling speed has the greatest effect on the surface integrity in the high-speed milling of the TB17 titanium alloy, and the contribution percentages for each factor are as follows: the cutting fluid condition (3.98%), milling speed (25.89%), feed per tooth (8.96%), axial depth of cut (1.29%), radial depth of cut (13.71%), rake angle (17.17%), clearance angle (6.62%), and helix angle (15.64%).

The structural mechanism of allosteric communication between retinoid X receptor (RXR) and its heterodimer partners remains controversial. As a first step towards addressing this question, we report a nuclear magnetic resonance (NMR) study on the GW1929-bound peroxisome proliferator-activated receptor gamma (PPARγ) ligand-binding domain (LBD) with and without the 9-cis-retinoic acid (9cRA)-bound RXRα LBD. Sequence-specific 13 C α , 13 C β and 13 CO resonance assignments have been established for over 95% of the 275 residues in the PPARγ LBD monomer. The 1 HN, 15 N and 13 CO chemical shift perturbations induced by the RXR LBD binding are located at not only the heterodimer interface that includes the C-terminal residue Y477, but also residues Y473 and K474 in the activation function-2 (AF-2) helix. This result suggests that 9cRA-bound RXRα can affect the PPARγ AF-2 helix in solution, and demonstrates that NMR is a powerful new tool for studying the mechanism of allosteric ligand activation in RXR heterodimers.