Miracle-dz/UniFAR-FTUs huggingface dataset:
Extender components and surfactants affect boar sperm function and membrane behavior during cryopreservation.

To determine how the individual components of extenders affected boar sperm function and membrane structure and to test a new surfactant's cryoprotective ability, boar sperm were cryopreserved in straws in BF5 extender plus or minus egg yolk plus or minus glycerol plus or minus a surfactant (Orvus ES Paste [OEP] or various concentrations of Pluronic F-127). After thawing, sperm function and fluidity of the isolated head plasma membrane (HPM) were determined. Total motility and adenosine triphosphate content (a measure of viability) were superior postthaw in sperm extended in egg yolk plus glycerol (P < 0.05); neither surfactant improved function. Egg yolk plus any other ingredients improved normal acrosome morphology, whereas a combined measure of motility and normal acrosome morphology was better in the presence of 0.33% OEP or 0.1% Pluronic F-127 (P < 0.05 vs. controls). Head plasma membrane was isolated from freshly collected spermatozoa and spermatozoa cryopreserved in the various extenders. Membrane fluidity was monitored with the probes cis-parinaric acid (cPNA), transparinaric acid (tPNA), and 1,6-diphenyl-1 ,3,5-hexatriene (DPH). The cPNA and the DPH monitor the fluidity of gel and liquid-crystalline areas of the membrane, whereas the tPNA preferentially monitors the gel-phase domains of the membrane. Additionally, DPH monitors the hydrophobic core of the bilayer. In the HPM from fresh sperm, the fluidity of each domain changed over time in a manner unique to that domain, and the behavior of the DPH domain varied among boars. The fluidity dynamics of each domain responded uniquely to cryopreservation. The cPNA domain was unaffected, the tPNA domain was altered by four of the eight extenders, and all extenders affected the fluidity of the DPH domain. Membrane structure was significantly correlated with cell function for sperm cryopreserved in extenders that preserved viability and motility. Sperm cryopreserved in egg yolk plus glycerol plus either OEP or 0.1% Pluronic F-127 functioned best when the bulk domains were less fluid initially and the gel domain solidified more slowly. Therefore, the behavior of domains in the HPM of boar spermatozoa is affected by cryopreservation and is related to the postthaw function of boar sperm cryopreserved in different extenders.
Mutagenesis studies of conserved proline residues of human P2X1 receptors for ATP indicate that proline 272 contributes to channel function

Proline residues can play a major role in the secondary structure of proteins. In the extracellular ATP binding loop of P2X receptors there are four totally conserved proline residues (P2X1 receptor numbering; P93, P166, P228 and P272) and three less conserved residues P196 (six of seven isoforms), P174 and P225 (five of seven isoforms). We have mutated individual conserved proline residues in the human P2X1 receptor and determined their properties. Mutants were expressed in Xenopus oocytes and characterized using a two‐electrode voltage clamp. Mutants P166A, P174A, P196A, P225A and P228A had no effect on ATP potency compared with wild‐type and P93A had a fourfold decrease in ATP potency. The P272A, P272D and P272K receptor mutants were expressed at the cell surface; however, these mutants were non‐functional. In contrast, P272I, P272G and P272F produced functional channels, with either no effect or a 2.5‐ or 6.5‐fold increase in ATP potency, respectively. At P272F receptors the apparent affinity of the ATP analogue antagonist 2′,3′‐O‐(2,4,6‐trinitrophenyl)‐ATP was increased by 12.5‐fold. These results suggest that individual proline residues are not essential for normal P2X receptor function and that the receptor conformation around P272 contributes to ATP binding at the receptor.
One Inch Thermal Bubble Jet Printhead With Laser Structured Integrated Polyimide Nozzle Plate

This paper reports on a novel 1/3 and 1-in thermal bubble jet printhead with integrated nozzle plate. The printheads are made by a combination of a standard printhead substrate with a new three-dimensional (3-D) structured polyimide nozzle plate avoiding a three-layer assembly known from other commercial printheads. The 50-mum- (respectively, 75-mum)-thick nozzle plate contains the fluidic channels and 208 (respectively, 312) nozzles with minimum lateral dimensions of 10 mum. The misalignment of the two laser structured layers has proved to be less than 1 mum. The nozzle plate is assembled with the substrate using a 3-mum-high adhesive layer with an alignment accuracy of 5 mum. The integrated nozzle plate leads to a better control of the printhead geometry and saves one processing step in production. A 1/3-in as well as a 1-in design were studied because it was not sure if the 1-in design survives the fabrication of the silicon substrate. The powder blasting of the ink feeding slot was considered as critical process step. To predict the effect of misalignments or variations in the adhesive layer during the assembling process on the characteristic inkjet parameters-like droplet volume, droplet velocity, droplet quality, or print frequency-computational fluid dynamic (CFD) simulations have been performed. For these purposes, a fully three-dimensional model was set up using the volume of fluid method. The presented CFD model in combination with the applied pressure boundary condition substituting the behavior of the exploding vapor bubble provides a valuable possibility to simulate media variations, actuation variations, as well as 3-D related geometrical variations. The differences in ejected droplet volume and droplet velocity between simulation and experiment are below 5%. Conclusively, the innovations presented in this paper are as follows. The presented printhead layout designed by Olivetti I-Jet provides an improved print frequency compared to commercially available printhead designs. The 1-in integrated nozzle plate and the required innovative fabrication technology offers a tripling of the printing speed compared to a conventional 1/3-in design only by means of an increased printing area. The new fabrication and packaging approach offers the reduction of processing and assembling steps leading to a better control of the printhead geometry. The CFD simulations provide a three-dimensional approach to estimate the influences of manufacturing and adjustment tolerances
Mutational analysis of the linker region of EnvZ, an osmosensor in Escherichia coli

EnvZ, a transmembrane signal transducer, is composed of a periplasmic sensor domain, transmembrane domains, and a cytoplasmic signaling domain. Between the second transmembrane domain and the cytoplasmic signaling domain there is a linker domain consisting of approximately 50 residues. In this study, we investigated the functional role of the EnvZ linker domain with respect to signal transduction. Amino acid sequence alignment of linker regions among various bacterial signal transducer proteins does not show a high sequence identity but suggests a common helix 1-loop-helix 2 structure. Among several mutations introduced in the EnvZ linker region, it was found that hydrophobic-to-charged amino acid substitutions in helix 1 and helix 2 and deletions in helix 1, loop, and helix 2 (delta14, delta8, and delta7) resulted in constitutive OmpC expression. In the linker mutant EnvZ x delta7, both kinase and phosphatase activities were significantly reduced but the ratio of kinase to phosphatase activity increased, consistent with the constitutive OmpC expression. In contrast, the purified cytoplasmic fragment of EnvZ x delta7 possessed both kinase and phosphatase activities at levels similar to those of the cytoplasmic fragment of wild-type EnvZ. In addition, the linker mutations had no direct effect on EnvZ C-terminal dimerization. These results together with previous data suggest that the linker region is not directly involved in EnvZ enzymatic activities and that it may have a crucial role in propagating a conformational change to ensure correct positioning of two EnvZ molecules within a dimer during the transmembrane signaling.