Search

Various laboratory-developed metabolomic methods lead to big challenges in inter-laboratory comparability and effective integration of diverse datasets. As part of the Quartet Project, we established a publicly available suite of four metabolite reference materials derived from B-lymphoblastoid cell lines from a family quartet of parents and monozygotic twin daughters. We generated comprehensive LC-MS based metabolomic data from the Quartet reference materials using targeted and untargeted strategies in different laboratories. High variabilities in the qualitative and quantitative metabolomic measurements were observed across laboratories. Moreover, the Quartet multi-sample-based quality metrics were developed for objectively assessing the reliability of metabolomic profiling in detecting intrinsic biological differences among difference groups of samples. Importantly, the ratio-based metabolomic profiling, by scaling the absolute values of a study sample relative to those of a universal reference sample, enables data integration in long-term measurements across difference laboratories or platforms. Thus, we constructed the ratio-based high-confidence reference datasets between two reference samples, providing “ground truth” for inter-laboratory proficiency test, which enables objective assessment of various metabolomic methods. Our study provided the community with rich resources and best practice for objective assessment of inter-laboratory measurements and data integration, ensuring reliable large-scale and longitudinal metabolomic profiling.

Syntrophy is essential for the efficient conversion of organic carbon to methane in natural and constructed environments, but little is known about the enzymes involved in syntrophic carbon and electron flow. Syntrophus aciditrophicus strain SB syntrophically degrades benzoate and cyclohexane-1-carboxylate and catalyses the novel synthesis of benzoate and cyclohexane-1-carboxylate from crotonate. We used proteomic, biochemical and metabolomic approaches to determine what enzymes are used for fatty, aromatic and alicyclic acid degradation versus for benzoate and cyclohexane-1-carboxylate synthesis. Enzymes involved in the metabolism of cyclohex-1,5-diene carboxyl-CoA to acetyl-CoA were in high abundance in S. aciditrophicus cells grown in pure culture on crotonate and in coculture with Methanospirillum hungatei on crotonate, benzoate or cyclohexane-1-carboxylate. Incorporation of 13 C-atoms from 1-[13 C]-acetate into crotonate, benzoate and cyclohexane-1-carboxylate during growth on these different substrates showed that the pathways are reversible. A protein conduit for syntrophic reverse electron transfer from acyl-CoA intermediates to formate was detected. Ligases and membrane-bound pyrophosphatases make pyrophosphate needed for the synthesis of ATP by an acetyl-CoA synthetase. Syntrophus aciditrophicus, thus, uses a core set of enzymes that operates close to thermodynamic equilibrium to conserve energy in a novel and highly efficient manner.

Single-seeded fruit of the sacred lotus Nelumbo nucifera Gaertn var. China Antique from NE China have been shown to remain viable for as long as ~1,300 years, determined by direct radiocarbon-dating, and to have a germination rate of 84 %. The pericarp, a fruit tissue that encloses the single seeds of Nelumbo, is one of the major factors contributing to fruit longevity. Proteins that are heat stable and have a protective function are equally important to such centuries-long seed viability. We document proteins of Nelumbo fruit that are able to withstand heating, 32 % of which remained soluble in the 110 °C-treated embryo axis of a 549-year-old fruit and 76 % retained fluidity in its cotyledons. The genome of Nelumbo has recently been published and annotated. The amino-acid sequences of 11 “thermal proteins” (soluble at 100 °C) of modern Nelumbo embryo axes and cotyledons, identified by mass spectrometry, Western blot and bioassay, are assembled and aligned with those of an archaeal hyperthermophile Methancaldococcus jannaschii (“Mj,” an anaerobic methanogen having a growth optimum of 85 °C) and with those of five mesophile angiosperms. These thermal proteins have roles in protection and repair under stress. More than half (55 %) of the durable Nelumbo thermal proteins are present in the archaean Mj, indicating their ancient history. One Nelumbo protein-repair enzyme exhibits activity at 100 °C, having a heat-tolerance higher than the comparable enzyme of Arabidopsis. A list of 30 sequenced but unassembled thermal proteins of Nelumbo is appended.

Syntrophus aciditrophicus is a model syntrophic bacterium that degrades key intermediates in anaerobic decomposition, such as benzoate, cyclohexane-1-carboxylate, and certain fatty acids, to acetate when grown with hydrogen-/formate-consuming microorganisms. ATP formation coupled to acetate production is the main source for energy conservation by S. aciditrophicus. However, the absence of homologs for phosphate acetyltransferase and acetate kinase in the genome of S. aciditrophicus leaves it unclear as to how ATP is formed, as most fermentative bacteria rely on these two enzymes to synthesize ATP from acetyl coenzyme A (CoA) and phosphate. Here, we combine transcriptomic, proteomic, metabolite, and enzymatic approaches to show that S. aciditrophicus uses AMP-forming, acetyl-CoA synthetase (Acs1) for ATP synthesis from acetyl-CoA. acs1 mRNA and Acs1 were abundant in transcriptomes and proteomes, respectively, of S. aciditrophicus grown in pure culture and coculture. Cell extracts of S. aciditrophicus had low or undetectable acetate kinase and phosphate acetyltransferase activities but had high acetyl-CoA synthetase activity under all growth conditions tested. Both Acs1 purified from S. aciditrophicus and recombinantly produced Acs1 catalyzed ATP and acetate formation from acetyl-CoA, AMP, and pyrophosphate. High pyrophosphate levels and a high AMP-to-ATP ratio (5.9 ± 1.4) in S. aciditrophicus cells support the operation of Acs1 in the acetate-forming direction. Thus, S. aciditrophicus has a unique approach to conserve energy involving pyrophosphate, AMP, acetyl-CoA, and an AMP-forming, acetyl-CoA synthetase., IMPORTANCE Bacteria use two enzymes, phosphate acetyltransferase and acetate kinase, to make ATP from acetyl-CoA, while acetate-forming archaea use a single enzyme, an ADP-forming, acetyl-CoA synthetase, to synthesize ATP and acetate from acetyl-CoA. Syntrophus aciditrophicus apparently relies on a different approach to conserve energy during acetyl-CoA metabolism, as its genome does not have homologs to the genes for phosphate acetyltransferase and acetate kinase. Here, we show that S. aciditrophicus uses an alternative approach, an AMP-forming, acetyl-CoA synthetase, to make ATP from acetyl-CoA. AMP-forming, acetyl-CoA synthetases were previously thought to function only in the activation of acetate to acetyl-CoA.

The human pathogen Trichomonas vaginalis lacks conventional mitochondria and instead contains divergent mitochondrial-related organelles. These double-membrane bound organelles, called hydrogenosomes, produce molecular hydrogen. Phylogenetic and biochemical analyses of hydrogenosomes indicate a common origin with mitochondria; however identification of hydrogenosomal proteins and studies on its metabolism have been limited. Here we provide a detailed proteomic analysis of the T. vaginalis hydrogenosome. The proteome of purified hydrogenosomes consists of 569 proteins, a number substantially lower than the 1,000 - 1,500 proteins reported for fungal and animal mitochondrial proteomes, yet considerably higher than proteins assigned to mitosomes. Pathways common to and distinct from both mitochondria and mitosomes were revealed by the hydrogenosome proteome. Proteins known to function in amino acid and energy metabolism, Fe-S cluster assembly, flavin-mediated catalysis, oxygen stress response, membrane translocation, chaperonin functions, proteolytic processing and ATP hydrolysis account for ∼30% of the hydrogenosome proteome. Of the 569 proteins in the hydrogenosome proteome, many appear to be associated with the external surface of hydrogenosomes, including large numbers of GTPases and ribosomal proteins. Glycolytic proteins were also found to be associated with the hydrogenosome proteome, similar to that previously observed for mitochondrial proteomes. Approximately 18% of the hydrogenosomal proteome is composed of hypothetical proteins of unknown function, predictive of multiple activities and properties yet to be uncovered for these highly adapted organelles.

An efficient GPU‐based sorting algorithm is proposed in this paper together with a merging method on graphics devices. The proposed sorting algorithm is optimized for modern GPU architecture with the capability of sorting elements represented by integers, floats and structures, while the new merging method gives a way to merge two ordered lists efficiently on GPU without using the slow atomic functions and uncoalesced memory read. Adaptive strategies are used for sorting disorderly or nearlysorted lists, large or small lists. The current implementation is on NVIDIA CUDA with multi‐GPUs support, and is being migrated to the new born Open Computing Language (OpenCL). Extensive experiments demonstrate that our algorithm has better performance than previous GPU‐based sorting algorithms and can support real‐time applications.

In this study, a label-free relative quantification strategy was developed for quantifying low-abundance glycoproteins in human serum. It included three steps: (1) immunodepletion of 12 high-abundance proteins, (2) enrichment of low-abundance glycoproteins by multi-lectin column, (3) relative quantification of them between different samples by micrOTOF-Q. We also evaluated the specificity and efficiency of immunodepletion, the accuracy of protein quantification and the possible influence of immunodepletion, glycoprotein enrichment, trypsin digestion and peptide ionization on quantification. In conclusion, the relative quantification method can be effectively applied to the screening of low-abundance biomarkers.

The proteome of human salivary fluid has the potential to open new doors for disease biomarker discovery. A recent study to comprehensively identify and catalog the human ductal salivary proteome led to the compilation of 1166 proteins. The protein complexity of both saliva and plasma is large, suggesting that a comparison of these two proteomes will provide valuable insight into their physiological significance and an understanding of the unique and overlapping disease diagnostic potential that each fluid provides. To create a more comprehensive catalog of human salivary proteins, we have first compiled an extensive list of proteins from whole saliva (WS) identified through MS experiments. The WS list is thereafter combined with the proteins identified from the ductal parotid, and submandibular and sublingual (parotid/SMSL) salivas. In parallel, a core dataset of the human plasma proteome with 3020 protein identifications was recently released. A total of 1939 nonredundant salivary proteins were compiled from a total of 19 474 unique peptide sequences identified from whole and ductal salivas; 740 out of the total 1939 salivary proteins were identified in both whole and ductal saliva. A total of 597 of the salivary proteins have been observed in plasma. Gene ontology (GO) analysis showed similarities in the distributions of the saliva and plasma proteomes with regard to cellular localization, biological processes, and molecular function, but revealed differences which may be related to the different physiological functions of saliva and plasma. The comprehensive catalog of the salivary proteome and its comparison to the plasma proteome provides insights useful for future study, such as exploration of potential biomarkers for disease diagnostics.

Noncovalent protein–ligand complexes are readily detected by electrospray ionization mass spectrometry (ESI-MS). Ligand binding stoichiometry can be determined easily by the ESI-MS method. The ability to detect noncovalent protein–ligand complexes depends, however, on the stability of the complexes in the gas-phase environment. Solution binding affinities may or may not be accurate predictors of their stability in vacuo. Complexes composed of cytidine nucleotides bound to ribonuclease A (RNase A) and ribonuclease S (RNase S) were detected by ESI-MS and were further analyzed by MS/MS. RNase A and RNase S share similar structures and biological activity. Subtilisin-cleavage of RNase A yields an S-peptide and an S-protein; the S-peptide and S-protein interact through hydrophobic interactions with a solution binding constant in the nanomolar range to generate an active RNase S. Cytidine nucleotides bind to the ribonucleases through electrostatic interactions with a solution binding constant in the micromolar range. Collisionally activated dissociation (CAD) of the 1:1 RNase A-CDP and CTP complexes yields cleavage of the covalent phosphate bonds of the nucleotide ligands, releasing CMP from the complex. CAD of the RNase S-CDP and CTP complexes dissociates the S-peptide from the remaining S-protein/nucleotide complex; further dissociation of the S-protein/nucleotide complex fragments a covalent phosphate bond of the nucleotide with subsequent release of CMP. Despite a solution binding constant favoring the S-protein/S-peptide complex, CDP/CTP remains electrostatically bound to the S-protein in the gas-phase dissociation experiment. This study highlights the intrinsic stability of electrostatic interactions in the gas phase and the significant differences in solution and gas-phase stabilities of noncovalent complexes that can result.

BACKGROUND: Cadmium ion (Cd2+) is a ubiquitous environmental contaminant, and it is a potent teratogen in mice. An intraperitoneal dose of 4 mg/kg of CdCl2 at gestational day 9 causes forelimb ectrodactyly in the C57BL/6N mouse strain, but the SWV/Fnn strain is resistant. The objective of this study was to identify differentially displayed proteins in two target tissues for cadmium teratogenesis, and to derive hypotheses regarding the mechanisms involved in the murine strain difference in Cd-induced forelimb ectrodactyly. METHODS: The global proteomics strategy used two-dimensional polyacrylamide gel electrophoresis for protein separation, and MALDI-TOF-MS and LC-MS/MS for protein identification, to compare and identify proteins in forelimb buds and yolk sacs from the two mouse strains following Cd administration. RESULTS: More than 1,000 protein spots were detected by two-dimensional polyacrylamide gel electrophoresis in day 10.0 mouse forelimb buds and yolk sacs. Thirty-eight proteins had identifiable differences in abundance levels in Cd-treated forelimb buds between the two strains. Of those 38 proteins, 14 could be associated with the unfolded protein response process and seven are associated with actin polymerization. The proteins that were found to be differentially abundant between the strains in yolk sacs that were exposed to CdCl2 were predominantly different than the proteins detected differentially in the limb buds of the two strains with an overlap of approximately 20%. CONCLUSIONS: These patterns of differentially displayed proteins rationalize a hypothesis that the differential murine strain response to cadmium-induced forelimb ectrodactyly is due to differences in their pathways for the unfolded protein response and/or actin polymerization. Birth Defects Research (Part A), 2008. © 2008 Wiley-Liss, Inc.

Cofilin, a member of the actin-depolymerizing factor (ADF)/cofilin family of proteins, is a key regulator of actin dynamics. Cofilin binds to monomer (G-) and filamentous (F-) actin, severs the filaments, and increases their turnover rate. Electron microscopy studies suggested cofilin interactions with subdomains 2 and 1/3 on adjacent actin protomers in F-actin. To probe for the presence of a cryptic cofilin binding site in subdomain 2 in G-actin, we used transglutaminase-mediated cross-linking, which targets Gln41 in subdomain 2. The cross-linking proceeded with up to 85% efficiency with skeletal alpha-actin and WT yeast actin, yielding a single product corresponding to a 1:1 actin-cofilin complex but was strongly inhibited in Q41C yeast actin (in which Q41 was substituted with cysteine). LC-MS/MS analysis of the proteolytic fragments of this complex mapped the cross-linking to Gln41 on actin and Gly1 on recombinant yeast cofilin. The actin-cofilin (AC) heterodimer was purified on FPLC for analytical ultracentrifugation and electron microscopy analysis. Sedimentation equilibrium and velocity runs revealed oligomers of AC in G-actin buffer. In the presence of excess cofilin, the covalent AC heterodimer bound a second cofilin, forming a 2:1 cofilin/actin complex, as revealed by sedimentation results. Under polymerizing conditions the cross-linked AC formed mostly short filaments, which according to image reconstruction were similar to uncross-linked actin-cofilin filaments. Although a majority of the cross-linking occurs at Gln41, a small fraction of the AC cross-linked complex forms in the Q41C yeast actin mutant. This secondary cross-linking site was sequenced by MALDI-MS/MS as linking Gln360 in actin to Lys98 on cofilin. Overall, these results demonstrate that the region around Gln41 (subdomain 2) is involved in a weak binding of cofilin to G-actin.

Surgical training systems using virtual reality simulation techniques offer a cost-effective alternative to traditional training methods. In this sense, techniques for interactive visualization and virtual reality surgery have been one of the very important research areas. We describe various techniques we have used in developing a virtual reality system for anatomic visualization and training arthroscopic knee surgeons. Virtual models used in our systems are constructed from the Visible Human Project and Chinese Visible Human data sets. We present our various developments in segmentation, personal-computer-based real-time volume visualization, soft tissue deformation with topological change in real-time using finite element analysis, and soft tissue cutting with tactile feedback.

Defensins are peptides that protect the host against microorganisms. Here we show that the theta-defensin retrocyclin 2 (RC2) inhibited influenza virus infection by blocking membrane fusion mediated by the viral hemagglutinin. RC2 was effective even after hemagglutinin attained a fusogenic conformation or had induced membrane hemifusion. RC2, a multivalent lectin, prevented hemagglutinin-mediated fusion by erecting a network of crosslinked and immobilized surface glycoproteins. RC2 also inhibited fusion mediated by Sindbis virus and baculovirus. Human beta-defensin 3 and mannan-binding lectin also blocked viral fusion by creating a protective barricade of immobilized surface proteins. This general mechanism might explain the broad-spectrum antiviral activity of many multivalent lectins of the innate immune system.

A large body of evidence has shown that exposure to ambient particulate matter (PM) leads to asthma exacerbation through an excitation of allergic inflammation. Utilizing diesel exhaust particles (DEPs) as a model air pollutant, we and others have demonstrated that PM contains redox-active chemicals that generate inflammation through an oxidative stress mechanism. Recently, the strengths of proteomics have enabled us to demonstrate that organic DEP extracts induce a hierarchical expression pattern of oxidative stress-induced proteins in macrophages and epithelial cells. As a further extension of this work, we now employ a new phosphosensor fluorescent dye, Pro-Q Diamond, to elucidate the induction of phosphoproteins and intracellular signaling cascades that may play a role in DEP-induced inflammation. We demonstrate that DEPs induced the phosphorylation of several phosphoproteins that belong to a number of signaling pathways as well as other oxidative stress pathways. In combination with cytokine array, phosphoproteome analysis using Pro-Q Diamond allowed us to characterize the aromatic and polar chemicals of DEPs that are involved in the activation of three different mitogen-activated protein (MAP) kinase signaling pathways.

The morphological distribution of oligosaccharides is determined in the egg jelly surrounding Xenopus laevis eggs. This biological system is used to illustrate a method for readily identifying and quantifying oligosaccharides in specific tissues. The extracellular matrix surrounding X. laevis eggs consists of a vitelline envelope and a jelly coat. The jelly coat contains three morphologically distinct layers designated J1, J2, and J3 from the innermost to the outermost and is composed of 9–11 distinct glycoproteins. Each jelly layer is known to have specific functions in the fertilization of the egg. We developed a rapid method to separate and identify the oligosaccharides from X. laevis egg jelly layers. Identification was based on the retention times in high-performance liquid chromatography (porous graphitized carbon column), exact masses, and tandem mass spectrometry. Over 40 neutral and 30 sulfated oligosaccharides were observed in the three jelly layers. Neutral oligosaccharide structures from different jelly layers were both unique and overlapping, while sulfated oligosaccharides were detected only in layers J1 and J2. Neutral oligosaccharides unique to jelly layer J3 and the combined layers J1 + J2 had similar core structures and similar residues. However, differences between these two sets of unique oligosaccharides were also observed and were primarily due to the branching carbohydrate moieties rather than the core structures.

Fullerenes with metal atoms substituted into the carbon framework have been observed in laser ablation studies of electrochemically prepared C60/Pt or C60/Ir(CO)2) films that contain polymeric, covalently bound chains: ···C60MLxC60MLxC60MLx··· (MLx = Ir(CO)2 or Pt). The C60/Pt film upon laser ablation produces the ions [C58Pt]- and [C56Pt]-, which result from the substitution of a platinum atom for two carbon atoms, and [C57Pt2]-, which incorporates two platinum atoms into the cage. The C60/Ir(CO)2 film produces a different series of products, [C59Ir]-, [C58Ir]-, [C57Ir]-, and [C56Ir]-, in which an iridium atom can replace one or two carbon atoms within the fullerene cage. Studies of the structures of [C58M]- by density functional theory (DFT) show that the isomer with the metal atom replacing the C2 unit at a 6:6 ring junction of the fullerene is more stable than the less symmetrical isomer with the metal replacing a C2 unit at a 5:6 ring junction. Evidence for the ability of the metal atoms in some of ...

Infrared multiphoton dissociation (IRMPD) of alkali metal-coordinated oligosaccharides was obtained in a Fourier transform mass spectrometer. Fragmentation of the oligosaccharides was observed for Li+- and Na+-coordinated species. For larger alkali metal ions (K+, Rb+, and Cs+), the major products were the alkali metal ions. IRMPD experiments were performed on milk oligosaccharides, and the dissociation thresholds were determined. The threshold values were found to differ for the isomers. It is suggested that the threshold may be useful for differentiating isomeric compounds. Additionally, oligosaccharide alditols from biological samples were analyzed. Comparison of the collision-induced dissociation (CID) and IRMPD spectra of oligosaccharide alditols revealed that IRMPD could be used as a complementary method to obtain structural information.

A new method for isolating ions for tandem mass spectrometry analyses in Fourier transform mass spectrometry is illustrated. The method employs an infrared laser to dissociate completely the undesired ions. The selected ions are excited to an orbit away from the degradative portion of the laser beam. Ion isolation was accomplished and tandem mass spectrometry experiments were performed on model oligosaccharides and compounds from biological samples.

A strategic method with high speed and sensitivity is outlined for the analysis of mucin-type oligosaccharide from the jelly coat of Xenopus laevis. The method relies primarily on mass spectrometric techniques, in this case matrix-assisted laser desorption/ionization Fourier-transform mass spectrometry (MALDI-FTMS) and collision-induced dissociation (CID). Separation with isolation of the oligosaccharides was streamlined to couple well with mass spectrometry allowing the rapid determination of all detectable components from both neutral and anionic species. Partial structures of anionic components, composed primarily of sulfate esters, were obtained with CID. For neutral species, a method that allowed the complete structural determination using mass spectrometry was used. The method builds on the structure of small number of known compounds to determine unknown structures from the same biological source. In this example, a small number of oligosaccharides, elucidated previously by NMR, were used to develop a set of substructural motifs that were characterized by CID. The presence of the motifs in the CID spectra were then used to determine the structures of unknown compounds that were in abundances too small for NMR analysis.

An overview of nitrification and denitrification in the natural environment is presented and the basic mechanisms of nitrification and denitrification in water/soil environments are described in this paper. Nitrification/denitrification is one of the most important techniques for removing inorganic nitrogenous compounds in water and soil environments. Nitrification and denitrification in aquatic and soil environments can be described by using First‐order kinetic and the methods for parameter estimation are discussed. The study indicated that nitrification and denitrification could take place simultaneously in aerobic and anaerobic zones in soil and water environment. The factors effecting nitrification and denitrification are discussed in this study. External carbon sources are the most important factors for completing denitrification and dissolved oxygen (DO) is very significant for nitrification.

Single-seeded fruit of the sacred lotus Nelumbo nucifera Gaertn var. China Antique from NE China have viability as long as ~1300 years determined by direct radiocarbon-dating, having a germination rate of 84%. The pericarp, a fruit tissue that encloses the single seeds of Nelumbo, is considered one of the major factors that contribute to fruit longevity. Proteins that are heat stable and have protective function may be equally important to seed viability. We show proteins of Nelumbo fruit that are able to withstand heating, 31% of which remained soluble in the 110°C-treated embryo-axis of a 549-yr-old fruit and 76% retained fluidity in its cotyledons. Genome of Nelumbo is published. The amino-acid sequences of 11 “thermal proteins” (soluble at 100°C) of modern Nelumbo embryo-axes and cotyledons, identified by mass spectrometry, Western blot and bioassay, are assembled and aligned with those of an archaeal-hyperthermophile Methancaldococcus jannaschii (Mj; an anaerobic methanogen having a growth optimum of 85°C) and with five mesophile angiosperms. These thermal proteins have roles in protection and repair under stress. More than half of the Nelumbo thermal proteins (55%) are present in the archaean Mj, indicating their long-term durability and history. One Nelumbo protein-repair enzyme exhibits activity at 100°C, having a higher heat-tolerance than that of Arabidopsis. A list of 30 sequenced but unassembled thermal proteins of Nelumbo is supplemented.

Physiological and proteomic responses of Sesuvium portulacastrum leaves under salinity were investigated. Different from glycophytes, this halophyte had optimal growth at 200–300 mM NaCl and accumulated more starch grains in chloroplasts under high salinity. Increased contents of soluble sugars, proline, and Na+ were observed upon salinity. X-ray microanalysis revealed that Na+ was mainly compartmentalized into cell vacuole. Quantitative proteomics produced 96 salt responsive proteins, and the majority was chloroplast-located proteins. Gene ontology analysis revealed that proteins involved in ion binding, proton transport, photosynthesis and ATP synthesis were overrepresented. The expressions of a Na+/H+ antiporter and several ATP synthase subunits were activated upon high salinity. ATP hydrolysis assay demonstrated that V-ATPase activity at tonoplast was dramatically increased upon NaCl whereas vacuolar H+-pyrophosphatase and plasma membrane P-ATPase activities were not increased, which indicated that sodium compartmentalization was mainly performed by enhancing V-ATPase activity rather than P-ATPase and H+-pyrophosphatase. Accumulation of soluble sugars as well as sodium compartmentalization maintained the osmotic balance between vacuole and cytoplasm, which finally established ionic homeostasis in saline cells in true halophytes. Biological significance Physiological and proteomic analyses of S. portulacastrum leaves under different salinities were investigated. This true halophyte accumulated more soluble sugars, starch, proline and Na+ under high salinity. Differential proteomics produced 96 salt responsive proteins and the majority was involved in ion binding, proton transport, photosynthesis, and ATP synthesis. A Na+/H+ antiporter and several ATP synthase subunits were induced upon high salinity. ATP hydrolysis assay demonstrated that V-ATPase activity at tonoplast was dramatically increased whereas vacuolar H+-pyrophosphatase and plasma membrane ATPase activities were stable upon NaCl. These findings demonstrated that the increased Na+ was compartmentalized into vacuole by enhancing V-ATPase activity rather than H+-ATPase.

Laboratory studies were conducted on the biodegradation of some selected lubricating oils. A standard method for determining the biodegradability of selected recalcitrant organic compounds was developed. Test results show that the species of bacteria present in the sample is an important factor affecting the biodegradation of selected lubricating oils. Results also indicate that it is difficult to degrade lubricating oils in water by using indigenous microorganisms in natural river or lake water. The study shows that up to 23% removal can be achieved biologically after 67 days of operation.

The same as in traditional surgery, surgeons in telerobotic surgery need extensive training to achieve experience and highly accurate instrument manipulation. Traditional training methods like practice in operating room have major drawbacks such as high risk and limited opportunity for which virtual reality (VR) and computer technologies can offer solutions. To accelerate the data transmission speed in our master-slave robotic simulator, GPUDirect was applied to ensure the synchronization and display rate of three computers. By using GPUDirect with InfiniBand card we realized up to 247% performance improvement in data transmission speed on NVIDIA Tesla™ products on different computers compared to that without GPUDirect, which shows that GPUDirect enables better communication between remote GPUs over InfiniBand.