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Sample records for monitoring glycerol secretion

  1. 2-Arachidonoyl glycerol sensitizes the pars distalis and enhances forskolin-stimulated prolactin secretion in Syrian hamsters.

    PubMed

    Yasuo, Shinobu; Fischer, Claudia; Bojunga, Joerg; Iigo, Masayuki; Korf, Horst-Werner

    2014-04-01

    2-Arachidonoyl glycerol (2-AG) is a major endocannabinoid and an important regulator of neuroendocrine system. In Syrian hamster and human, we found that 2-AG is synthesized in the hypophysial pars tuberalis (PT), an interface between photoperiodic melatonin signals and neuroendocrine output pathways. The target of 2-AG produced in the PT is likely to be the pars distalis (PD). Here we demonstrate that 2-AG in combination with forskolin stimulated prolactin secretion from PD organ cultures of Syrian hamsters, whereas incubation with 2-AG alone had no effect. Forskolin-induced prolactin secretion was also significantly enhanced when cultured PD tissue was preincubated with 2-AG. The stimulatory effects of 2-AG on prolactin secretion were blocked by AM251, a selective CB1 antagonist, and were still observed in the presence of quinpirole, a D2-class dopamine receptor agonist. 2-AG also enhanced prolactin secretion in the presence of adenosine, while it had little effect when applied together with adenosine diphosphate (ADP) and adenosine triphosphate (ATP). Moreover, the effect of forskolin was mimicked by adenosine in a dose-dependent manner. In conclusion, our data suggest that 2-AG sensitizes the PD tissue to potentiate the stimulating effects of forskolin and adenosine on prolactin secretion and thus provide novel insight into the mode of action of 2-AG in the PD. PMID:24200164

  2. Monitoring of monosaccharides, oligosaccharides, ethanol and glycerol during wort fermentation by biosensors, HPLC and spectrophotometry.

    PubMed

    Monošík, Rastislav; Magdolen, Peter; Stredanský, Miroslav; Šturdík, Ernest

    2013-05-01

    The aim of the present study was to analyze sugar levels (namely maltose, maltotriose, glucose and fructose) and alcohols (ethanol and glycerol) during the fermentation process in wort samples by amperometric enzymatic biosensors developed by our research group for industrial application, HPLC and spectrophotometry, and to compare the suitability of the presented methods for determination of individual analytes. We can conclude that for the specific monitoring of maltose or maltotriose only the HPLC method was suitable. On the other hand, biosensors and spectrophotometry reflected a decrease in total sugar concentration better and were able to detect both glucose and fructose in the later stages of fermentation, while HPLC was not. This can be attributed to the low detection limits and good sensitivity of the proposed methods. For the ethanol and glycerol analysis all methods proved to be suitable. However, concerning the cost expenses and time analysis, biosensors represented the best option. PMID:23265480

  3. OCT monitoring of diffusion of water and glycerol through tooth dentine in different geometry of wetting

    NASA Astrophysics Data System (ADS)

    Trunina, N. A.; Lychagov, V. V.; Tuchin, V. V.

    2010-02-01

    In our previous work optical coherence tomography (OCT) has been proved to be a useful tool for monitoring of diffusion of chemical agents (water, glycerol) within human tooth dentine. Such diffusion studies are interesting for tooth therapy (diffusion of medicinal preparations) and cosmetics (chemical whitening agents). Here we compare different wetting schemes in which the sample is either merged in the liquid agent so that the probe beam is to pass through a layer of liquid, or subjected to wetting through a special window from the back side. In spite of certain difference revealed, the order of magnitude of the diffusion time constant and the permeability coefficient are shown to be the same in both cases.

  4. The use of capillary electrophoresis with contactless conductivity detection for monitoring of glycerol in adipose tissues during a sporting performance.

    PubMed

    Tůma, Petr; Málková, Klára; Wedellová, Zuzana; Samcová, Eva; Stulík, Karel

    2010-06-01

    A CE procedure employing capacitively coupled contactless conductivity detection has been developed for direct determination of the glycerol and mannitol polyalcohols in biological and pharmacological samples. Both glycerol and mannitol are fully separated from the sample matrix within very short times of 3.0 and 3.9 min, respectively, when using the optimized BGE, 60 mM H3BO3+30 mM LiOH (pH 9.1). The LODs amount to 0.5 microM for glycerol and 0.3 microM for mannitol. The repeatability of the glycerol determination in real biological materials is characterized by the coefficient of variation values, 0.5 and 3.2%, for the migration time and the peak area, respectively. The procedure has been used to monitor the free glycerol concentration in adipose tissue microdialyzates. A physiological study has demonstrated that the lipolysis occurring during a sporting action can be stimulated by local application of adrenaline. The procedure has further been utilized to determine mannitol in a pharmacological preparation. PMID:20564696

  5. In vivo determination of triglyceride (TG) secretion in rats fed different dietary saturated fats using (2- sup 3 H)-glycerol

    SciTech Connect

    Lai, H.C.; Yang, H.; Lasekan, J.; Clayton, M.; Ney, D.M. )

    1990-02-26

    Male, Sprague-Dawley rats (154{plus minus}1 g) were fed diets containing 2% corn oil (CO) + 14% butterfat (BF), beef tallow (BT), olive oil (OO) or coconut oil (CN) vs a 16% CO control diet for 5 weeks. Changes in plasma TG specific activity (dpm/mg TG) were determined in individual unanesthetized rats after injection of 100 {mu}Ci (2-{sup 3}H)-glycerol via a carotid cannula. Fractional rate constants were obtained using a 2-compartment model and nonlinear regression analysis. Results demonstrated no difference in the fractional rate constants among dietary groups; but, differences in the rates of hepatic TG secretion were noted. Rats fed BT showed a higher rate of hepatic TG secretion than rats fed CO. Rats fed BF, OO or CN showed somewhat higher rates of hepatic TG secretion than CO. VLDL TG, phospholipid, and apolipoprotein B and E levels were higher with saturated fats vs CO. The data suggest that the higher plasma TG levels noted in response to feeding saturated fats vs corn oil can be explained, in part, by an increased flux of hepatic TG secretion.

  6. Dynamic OCT monitoring and quantification of light penetration enhancement for normal, benign and cancerous human lung tissues at different concentrations of glycerol

    NASA Astrophysics Data System (ADS)

    Tan, Shu-wen; Jin, Ying; Yu, Hui; Wu, Guo-yong

    2013-10-01

    We have evaluated the dynamic effects of the analyte diffusion on the 1/e light penetration depths of normal, benign and cancerous human lung tissue in vitro, as well as have monitored and quantified the dynamic change in the light penetration depths of the mentioned human lung tissue after application of 25 % and 50 % glycerol solution, respectively. The light penetration depths of the analyte diffusion in the lung tissue are measured using the Fourierdomain optical coherence tomography (FD-OCT). Experimental results show that the application of glycerol as a chemical agent can significantly enhance light penetration depths into the human normal lung (NL), lung benign granulomatosis (LBG) and lung squamous cell carcinoma (LSCC) tissue. In-depth transport of the glycerol molecules in the NL, LBG and LSCC tissue at a lower glycerol concentration (25 %) are faster than those at a higher glycerol concentration (50 %), and the 1/e light penetration depths at a lower glycerol concentration (25 %) are smaller than those at a higher glycerol concentration (50 %), respectively. Their differences in the maximal 1/e light penetration depths of the NL, LBG and LSCC tissue at a higher and a lower glycerol concentrations were only 8.8 %, 6.8 % and 4.7 %, respectively.

  7. Dynamic OCT monitoring and quantification of light penetration enhancement for normal, benign and cancerous human lung tissues at different concentrations of glycerol

    SciTech Connect

    Shu-wen Tan; Ying Jin; Hui Yu; Guo-yong Wu

    2013-10-31

    We have evaluated the dynamic effects of the analyte diffusion on the 1/e light penetration depths of normal, benign and cancerous human lung tissue in vitro, as well as have monitored and quantified the dynamic change in the light penetration depths of the mentioned human lung tissue after application of 25 % and 50 % glycerol solution, respectively. The light penetration depths of the analyte diffusion in the lung tissue are measured using the Fourierdomain optical coherence tomography (FD-OCT). Experimental results show that the application of glycerol as a chemical agent can significantly enhance light penetration depths into the human normal lung (NL), lung benign granulomatosis (LBG) and lung squamous cell carcinoma (LSCC) tissue. In-depth transport of the glycerol molecules in the NL, LBG and LSCC tissue at a lower glycerol concentration (25 %) are faster than those at a higher glycerol concentration (50 %), and the 1/e light penetration depths at a lower glycerol concentration (25 %) are smaller than those at a higher glycerol concentration (50 %), respectively. Their differences in the maximal 1/e light penetration depths of the NL, LBG and LSCC tissue at a higher and a lower glycerol concentrations were only 8.8 %, 6.8 % and 4.7 %, respectively. (biophotonics)

  8. Monitoring of dihydroxyacetone production during oxidation of glycerol by immobilized Gluconobacter oxydans cells with an enzyme biosensor.

    PubMed

    Tkác, J; Navrátil, M; Sturdík, E; Gemeiner, P

    2001-03-01

    A bi-enzymatic biosensor for monitoring of dihydroxyacetone production during oxidation of glycerol by bacterial cells of Gluconobacter oxydans is presented. Galactose oxidase oxidizes dihydroxyacetone efficiently producing hydrogen peroxide, which reacts with co-immobilized peroxidase and ferrocene pre-adsorbed on graphite electrode. This mediator-based bi-enzymatic biosensor possesses very high sensitivity (4.7 µA/mM in phosphate buffer), low detection limit (0.8 µM, signal/noise = 3), short response time (22 s, 95% of steady-state) and broad linear range (0.002-0.55 mM in phosphate buffer). The effect of pH, temperature, type of buffer, as well as different stabilizers (combinations of a polyelectrolyte and a polyol) on the sensor performance were carefully optimized and discussed. Dihydroxyacetone produced during a batch conversion of glycerol by the pectate-immobilized bacteria in an air-lift reactor was determined by the biosensor and by reference spectrophotometric method. Both methods were compared and were in a very good correlation. The main advantage of the biosensor is a very short time needed for sample analysis (less than 1 min). PMID:11240195

  9. A sampling design framework for monitoring secretive marshbirds

    USGS Publications Warehouse

    Johnson, D.H.; Gibbs, J.P.; Herzog, M.; Lor, S.; Niemuth, N.D.; Ribic, C.A.; Seamans, M.; Shaffer, T.L.; Shriver, W.G.; Stehman, S.V.; Thompson, W.L.

    2009-01-01

    A framework for a sampling plan for monitoring marshbird populations in the contiguous 48 states is proposed here. The sampling universe is the breeding habitat (i.e. wetlands) potentially used by marshbirds. Selection protocols would be implemented within each of large geographical strata, such as Bird Conservation Regions. Site selection will be done using a two-stage cluster sample. Primary sampling units (PSUs) would be land areas, such as legal townships, and would be selected by a procedure such as systematic sampling. Secondary sampling units (SSUs) will be wetlands or portions of wetlands in the PSUs. SSUs will be selected by a randomized spatially balanced procedure. For analysis, the use of a variety of methods as a means of increasing confidence in conclusions that may be reached is encouraged. Additional effort will be required to work out details and implement the plan.

  10. Novel Authentication of Monitoring Data Through the use of Secret and Public Cryptographic Keys

    SciTech Connect

    Benz, Jacob M.; Tolk, Keith; Tanner, Jennifer E.

    2014-07-21

    The Office of Nuclear Verification (ONV) is supporting the development of a piece of equipment to provide data authentication and protection for a suite of monitoring sensors as part of a larger effort to create an arms control technology toolkit. This device, currently called the Red Box, leverages the strengths of both secret and public cryptographic keys to authenticate, digitally sign, and pass along monitoring data to allow for host review, and redaction if necessary, without the loss of confidence in the authenticity of the data by the monitoring party. The design of the Red Box will allow for the addition and removal of monitoring equipment and can also verify that the data was collected by authentic monitoring equipment prior to signing the data and sending it to the host and for review. The host will then forward the data to the monitor for review and inspection. This paper will highlight the progress to date of the Red Box development, and will explain the novel method of leveraging both symmetric and asymmetric (secret and public key) cryptography to authenticate data within a warhead monitoring regime.

  11. Artificial MicroRNAs as Novel Secreted Reporters for Cell Monitoring in Living Subjects

    PubMed Central

    Chuang, Hui-Yen; Gambhir, Sanjiv Sam

    2016-01-01

    Reporter genes are powerful technologies that can be used to directly inform on the fate of transplanted cells in living subjects. Imaging reporter genes are often employed to quantify cell number, location(s), and viability with various imaging modalities. To complement this, reporters that are secreted from cells can provide a low-cost, in vitro diagnostic test to monitor overall cell viability at relatively high frequency without knowing the locations of all cells. Whereas protein-based secretable reporters have been developed, an RNA-based reporter detectable with amplification inherent PCR-based assays has not been previously described. MicroRNAs (miRNAs) are short non-coding RNAs (18–22 nt) that regulate mRNA translation and are being explored as relatively stable blood-based disease biomarkers. We developed an artificial miRNA-based secreted reporter, called Sec-miR, utilizing a coding sequence that is not expressed endogenously and does not have any known vertebrate target. Sec-miR was detectable in both the cells and culture media of transiently transfected cells. Cells stably expressing Sec-miR also reliably secreted it into the culture media. Mice implanted with parental HeLa cells or HeLa cells expressing both Sec-miR and the bioluminescence imaging (BLI) reporter gene Firefly luciferase (FLuc) were monitored over time for tumor volume, FLuc signal via BLI, and blood levels of Sec-miR. Significantly (p<0.05) higher Sec-miR was found in the blood of mice bearing Sec-miR-expressing tumors compared to parental cell tumors at 21 and 28 days after implantation. Importantly, blood Sec-miR reporter levels after day 21 showed a trend towards correlation with tumor volume (R2 = 0.6090; p = 0.0671) and significantly correlated with FLuc signal (R2 = 0.7067; p<0.05). Finally, we could significantly (p<0.01) amplify Sec-miR secretion into the cell media by chaining together multiple Sec-miR copies (4 instead of 1 or 2) within an expression cassette. Overall, we

  12. Artificial MicroRNAs as Novel Secreted Reporters for Cell Monitoring in Living Subjects.

    PubMed

    Ronald, John A; D'Souza, Aloma L; Chuang, Hui-Yen; Gambhir, Sanjiv Sam

    2016-01-01

    Reporter genes are powerful technologies that can be used to directly inform on the fate of transplanted cells in living subjects. Imaging reporter genes are often employed to quantify cell number, location(s), and viability with various imaging modalities. To complement this, reporters that are secreted from cells can provide a low-cost, in vitro diagnostic test to monitor overall cell viability at relatively high frequency without knowing the locations of all cells. Whereas protein-based secretable reporters have been developed, an RNA-based reporter detectable with amplification inherent PCR-based assays has not been previously described. MicroRNAs (miRNAs) are short non-coding RNAs (18-22 nt) that regulate mRNA translation and are being explored as relatively stable blood-based disease biomarkers. We developed an artificial miRNA-based secreted reporter, called Sec-miR, utilizing a coding sequence that is not expressed endogenously and does not have any known vertebrate target. Sec-miR was detectable in both the cells and culture media of transiently transfected cells. Cells stably expressing Sec-miR also reliably secreted it into the culture media. Mice implanted with parental HeLa cells or HeLa cells expressing both Sec-miR and the bioluminescence imaging (BLI) reporter gene Firefly luciferase (FLuc) were monitored over time for tumor volume, FLuc signal via BLI, and blood levels of Sec-miR. Significantly (p<0.05) higher Sec-miR was found in the blood of mice bearing Sec-miR-expressing tumors compared to parental cell tumors at 21 and 28 days after implantation. Importantly, blood Sec-miR reporter levels after day 21 showed a trend towards correlation with tumor volume (R2 = 0.6090; p = 0.0671) and significantly correlated with FLuc signal (R2 = 0.7067; p<0.05). Finally, we could significantly (p<0.01) amplify Sec-miR secretion into the cell media by chaining together multiple Sec-miR copies (4 instead of 1 or 2) within an expression cassette. Overall, we

  13. Dynamic-SERS Optophysiology: A Nanosensor for Monitoring Cell Secretion Events.

    PubMed

    Lussier, Félix; Brulé, Thibault; Vishwakarma, Medhavi; Das, Tamal; Spatz, Joachim P; Masson, Jean-François

    2016-06-01

    We monitored metabolite secretion near living cells using a plasmonic nanosensor. The nanosensor created from borosilicate nanopipettes analogous to the patch clamp was decorated with Au nanoparticles and served as a surface-enhanced Raman scattering (SERS) substrate with addressable location. With this nanosensor, we acquired SERS locally near Madin-Darby canine kidney (MDCKII) epithelial cells, and we detected multiple metabolites, such as pyruvate, lactate, ATP, and urea simultaneously. These plasmonic nanosensors were capable of monitoring metabolites in the extracellular medium with enough sensitivity to detect an increase in metabolite concentration following the lyses of MDCKII cells with a nonionic surfactant. The plasmonic nanosensors also allowed a relative quantification of a chemical gradient for a metabolite near cells, as demonstrated with a decrease in relative lactate to pyruvate concentration further away from the MDCKII cells. This SERS optophysiology technique for the sensitive and nondestructive monitoring of extracellular metabolites near living cells is broadly applicable to different cellular and tissue models and should therefore provide a powerful tool for cellular studies. PMID:27172291

  14. Monitoring circadian time in rat plasma using a secreted Cypridina luciferase reporter.

    PubMed

    Yamada, Yoshiko; Nishide, Shin-Ya; Nakajima, Yoshihiro; Watanabe, Toshiyuki; Ohmiya, Yoshihiro; Honma, Ken-Ichi; Honma, Sato

    2013-08-15

    A firefly luciferase reporter enabled us to monitor promoter activity in vivo as well as ex vivo; however, this requires a sufficient supply of the substrate luciferin and specific monitoring devices. To overcome these disadvantages, we developed transgenic rats carrying a secreted enzyme Cypridina luciferase (CLuc) reporter under the promoter of clock gene Per2 (Per2-CLuc). Per2-CLuc activity in serially sampled blood from freely moving rats exhibited robust circadian rhythms with a peak at early morning. The Per2-CLuc bioluminescence could be quantified even with approximately 100pl of plasma. Plasma Per2-CLuc rhythms were phase reversed, and the level was reduced by restricting food access for 2h during the light phase, suggesting that the plasma Per2-CLuc rhythms reflect the phase of peripheral clocks entrained to feeding cues as well as fuel metabolism. Fasting for 2days did not alter the circadian Per2-CLuc rhythms in rats, suggesting that feeding per se did not affect the circadian Per2-CLuc rhythms. Tissue-specific Per2-CLuc rhythms were observed in culture medium of peripheral tissues. The Per2-CLuc reporter is a powerful tool to access gene expression in vivo as well as ex vivo with ordinary laboratory equipment. PMID:23624321

  15. Glycerol combustion and emissions

    EPA Science Inventory

    With the growing capacity in biodiesel production and the resulting glut of the glycerol by-product, there is increasing interest in finding alternative uses for crude glycerol. One option may be to burn it locally for combined process heat and power, replacing fossil fuels and i...

  16. Preparation of Glycerol Cinnamate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glycerol was combined with cinnamic acid to prepare the corresponding ester, glycerol cinnamate. Conversions of 81% were achieved after 16 hr in toluene at reflux conditions. The product was recovered by extraction with distilled water and diethyl ether. The isolated product displayed strong abso...

  17. Monitoring nasal allergic inflammation by measuring the concentration of eosinophil cationic protein and eosinophils in nasal secretions.

    PubMed

    Wang, D; Clement, P; Smitz, J; de Waele, M; Derde, M P

    1995-02-01

    Quantitative measurement of the eosinophil cationic protein (ECP) concentration and the percentage of eosinophils in nasal secretions has greatly improved our understanding of the inflammatory process after natural allergen exposure. ECP and eosinophils were measured in the nasal secretions of 40 symptomatic patients with seasonal allergic rhinitis during the pollen season. Results showed a significant relationship between a high concentration of ECP (median: 410 ng/g, range: 6-2380 ng/g) and a high percentage of eosinophils (median: 13.5%, range: 1-85%). This quantitative study again demonstrated that infiltration by eosinophils and release of ECP play a key role in allergic rhinitis. It also suggests that the combined measurement of the percentage of eosinophils together with the ECP concentration in nasal secretions seems to be a very useful model in monitoring and assessing the condition of chronic nasal inflammation in patients with allergic rhinitis. PMID:7604937

  18. Automated microfluidic platform of bead-based electrochemical immunosensor integrated with bioreactor for continual monitoring of cell secreted biomarkers

    PubMed Central

    Riahi, Reza; Shaegh, Seyed Ali Mousavi; Ghaderi, Masoumeh; Zhang, Yu Shrike; Shin, Su Ryon; Aleman, Julio; Massa, Solange; Kim, Duckjin; Dokmeci, Mehmet Remzi; Khademhosseini, Ali

    2016-01-01

    There is an increasing interest in developing microfluidic bioreactors and organs-on-a-chip platforms combined with sensing capabilities for continual monitoring of cell-secreted biomarkers. Conventional approaches such as ELISA and mass spectroscopy cannot satisfy the needs of continual monitoring as they are labor-intensive and not easily integrable with low-volume bioreactors. This paper reports on the development of an automated microfluidic bead-based electrochemical immunosensor for in-line measurement of cell-secreted biomarkers. For the operation of the multi-use immunosensor, disposable magnetic microbeads were used to immobilize biomarker-recognition molecules. Microvalves were further integrated in the microfluidic immunosensor chip to achieve programmable operations of the immunoassay including bead loading and unloading, binding, washing, and electrochemical sensing. The platform allowed convenient integration of the immunosensor with liver-on-chips to carry out continual quantification of biomarkers secreted from hepatocytes. Transferrin and albumin productions were monitored during a 5-day hepatotoxicity assessment in which human primary hepatocytes cultured in the bioreactor were treated with acetaminophen. Taken together, our unique microfluidic immunosensor provides a new platform for in-line detection of biomarkers in low volumes and long-term in vitro assessments of cellular functions in microfluidic bioreactors and organs-on-chips. PMID:27098564

  19. Automated microfluidic platform of bead-based electrochemical immunosensor integrated with bioreactor for continual monitoring of cell secreted biomarkers.

    PubMed

    Riahi, Reza; Shaegh, Seyed Ali Mousavi; Ghaderi, Masoumeh; Zhang, Yu Shrike; Shin, Su Ryon; Aleman, Julio; Massa, Solange; Kim, Duckjin; Dokmeci, Mehmet Remzi; Khademhosseini, Ali

    2016-01-01

    There is an increasing interest in developing microfluidic bioreactors and organs-on-a-chip platforms combined with sensing capabilities for continual monitoring of cell-secreted biomarkers. Conventional approaches such as ELISA and mass spectroscopy cannot satisfy the needs of continual monitoring as they are labor-intensive and not easily integrable with low-volume bioreactors. This paper reports on the development of an automated microfluidic bead-based electrochemical immunosensor for in-line measurement of cell-secreted biomarkers. For the operation of the multi-use immunosensor, disposable magnetic microbeads were used to immobilize biomarker-recognition molecules. Microvalves were further integrated in the microfluidic immunosensor chip to achieve programmable operations of the immunoassay including bead loading and unloading, binding, washing, and electrochemical sensing. The platform allowed convenient integration of the immunosensor with liver-on-chips to carry out continual quantification of biomarkers secreted from hepatocytes. Transferrin and albumin productions were monitored during a 5-day hepatotoxicity assessment in which human primary hepatocytes cultured in the bioreactor were treated with acetaminophen. Taken together, our unique microfluidic immunosensor provides a new platform for in-line detection of biomarkers in low volumes and long-term in vitro assessments of cellular functions in microfluidic bioreactors and organs-on-chips. PMID:27098564

  20. Automated microfluidic platform of bead-based electrochemical immunosensor integrated with bioreactor for continual monitoring of cell secreted biomarkers

    NASA Astrophysics Data System (ADS)

    Riahi, Reza; Shaegh, Seyed Ali Mousavi; Ghaderi, Masoumeh; Zhang, Yu Shrike; Shin, Su Ryon; Aleman, Julio; Massa, Solange; Kim, Duckjin; Dokmeci, Mehmet Remzi; Khademhosseini, Ali

    2016-04-01

    There is an increasing interest in developing microfluidic bioreactors and organs-on-a-chip platforms combined with sensing capabilities for continual monitoring of cell-secreted biomarkers. Conventional approaches such as ELISA and mass spectroscopy cannot satisfy the needs of continual monitoring as they are labor-intensive and not easily integrable with low-volume bioreactors. This paper reports on the development of an automated microfluidic bead-based electrochemical immunosensor for in-line measurement of cell-secreted biomarkers. For the operation of the multi-use immunosensor, disposable magnetic microbeads were used to immobilize biomarker-recognition molecules. Microvalves were further integrated in the microfluidic immunosensor chip to achieve programmable operations of the immunoassay including bead loading and unloading, binding, washing, and electrochemical sensing. The platform allowed convenient integration of the immunosensor with liver-on-chips to carry out continual quantification of biomarkers secreted from hepatocytes. Transferrin and albumin productions were monitored during a 5-day hepatotoxicity assessment in which human primary hepatocytes cultured in the bioreactor were treated with acetaminophen. Taken together, our unique microfluidic immunosensor provides a new platform for in-line detection of biomarkers in low volumes and long-term in vitro assessments of cellular functions in microfluidic bioreactors and organs-on-chips.

  1. Electrochemical valorisation of glycerol.

    PubMed

    Simões, Mário; Baranton, Stève; Coutanceau, Christophe

    2012-11-01

    The worldwide glycerol stocks are increasing; to make the biodiesel industry sustainable economically, this chemical could be used as a secondary primary raw material. Electric energy or hydrogen and added-value-chemical cogeneration becomes more and more an important research topic for increasing economical and industrial interests towards electrochemical technologies. Studies on glycerol electrooxidation for fuel or electrolysis cell applications are scarce. The valorisation of glycerol is generally performed by organic chemistry reactions forming, for example, esters, glycerol carbonates, ethers, acetals or ketals. Glycerol oxidation is made up of complex pathway reactions that can produce a large number of useful intermediates or valuable fine chemicals with presently limited market impact due to expensive production processes. Many of these chemical oxidation routes lead to significant amounts of undesired by-products, and enzymatic processes are limited. Converse to classical heterogeneous processes, electrocatalytic oxidation processes can be tuned by controlling the nature, composition and structure of the electrocatalyts as well as the electrode potential. Such control may lead to very high selectivity and activity, avoiding or limiting product separation steps. The coupling of glycerol oxidation to produce chemicals with the oxygen reduction reaction in a fuel cell or water reduction reaction in an electrolysis cell on Pt-free catalysts results either in coproduction of electrical energy or hydrogen for energy storage. PMID:23112136

  2. Glycerol-induced hyperhydration

    NASA Technical Reports Server (NTRS)

    Riedesel, Marvin L.; Lyons, Timothy P.; Mcnamara, M. Colleen

    1991-01-01

    Maintenance of euhydration is essential for maximum work performance. Environments which induce hypohydration reduce plasma volume and cardiovascular performance progressively declines as does work capacity. Hyperhydration prior to exposure to dehydrating environments appears to be a potential countermeasure to the debilitating effects of hypohydration. The extravascular fluid space, being the largest fluid compartment in the body, is the most logical space by which significant hyperhydration can be accomplished. Volume and osmotic receptors in the vascular space result in physiological responses which counteract hyperhydration. Our hypothesis is that glycerol-induced hyperhydration (GIH) can accomplish extravascular fluid expansion because of the high solubility of glycerol in lipid and aqueous media. A hypertonic solution of glycerol is rapidly absorbed from the gastrointestinal tract, results in mild increases in plasma osmolality and is distributed to 65 percent of the body mass. A large volume of water ingested within minutes after glycerol intake results in increased total body water because of the osmotic action and distribution of glycerol. The resulting expanded extravascular fluid space can act as a reservoir to maintain plasma volume during exposure to dehydrating environments. The fluid shifts associated with exposure to microgravity result in increased urine production and is another example of an environment which induces hypohydration. Our goal is to demonstrate that GIH will facilitate maintenance of euhydration and cardiovascular performance during space flight and upon return to a 1 g environment.

  3. Assessment of lactotroph axis functionality in mice: longitudinal monitoring of PRL secretion by ultrasensitive-ELISA.

    PubMed

    Guillou, Anne; Romanò, Nicola; Steyn, Frederik; Abitbol, Karine; Le Tissier, Paul; Bonnefont, Xavier; Chen, Chen; Mollard, Patrice; Martin, Agnès O

    2015-05-01

    The pattern of prolactin (PRL) secretion depends on the physiological state. Due to insufficient detection sensitivity of existing assays, the precise description of these patterns in mice is lacking. We described an ultrasensitive ELISA assay that can detect mouse PRL in small fractions of whole blood, allowing longitudinal studies of PRL secretion profiles in freely moving mice. Over a 24-hour period, males displayed no oscillation in PRL levels, whereas virgin and lactating females showed large pulses. Peaks of PRL secretion reached 30-40 ng/mL in lactating female mice and rarely exceeded 10 ng/mL in virgin females. These pulses of PRL in lactating females were associated with suckling. The return of pups after an experimental 12-hour weaning induced a pulse of PRL release, reaching 100 ng/mL. This approach also enabled us to assess the inhibitory tone from hypothalamic dopamine neurons on PRL secretion. We used a dopamine D2 receptor antagonist to relieve pituitary lactotrophs from the tuberoinfundibular dopaminergic inhibitory tone and demonstrate a D2-induced PRL rise that can be used to evaluate both the secretory capacity of lactotrophs and the magnitude of the inhibitory tone on pituitary PRL release. We demonstrate that, although lactotroph function is altered to enhance chronic PRL output, their secretory response to acute stimulus is not modified during lactation and that chronic hyperprolactinemia is linked to a lower inhibitory tone. The combination of a sensitive PRL ELISA and administration of D2 receptor antagonist provide a unique opportunity to investigate the function and plasticity of the lactotroph axis in freely moving mice. PMID:25643154

  4. Genetic Targeting of a Small Fluorescent Zinc Indicator to Cell Surface for Monitoring Zinc Secretion

    PubMed Central

    Li, Daliang; Liu, Lin; Li, Wen-Hong

    2015-01-01

    Numerous mammalian cells contain Zn2+ in their secretory granules. During secretion, Zn2+ is coreleased with granular cargos into extracellular medium so Zn2+ serves as a convenient surrogate marker for tracking the dynamics of secretion. Fluorescent Zn2+ sensors that can be selectively targeted to cells of interest would be invaluable tools for imaging Zn2+ release in multicellular systems including tissues and live animals. Exploiting the HaloTag labeling technology and using an optimized linker, we have engineered a fluorescent Zn2+ indicator that displayed a 15-fold fluorescence enhancement upon Zn2+ binding while reacting efficiently with a HaloTag enzyme in a cellular environment. Two-color imaging of ZIMIR-HaloTag and a red-emitting calcium indicator in pancreatic islet beta cells demonstrated that photoactivation of a channelrhodopsin was able to induce exocytosis of Zn2+/insulin granules and revealed heterogeneity in secretory activity along the cell membrane that was uncoupled from cellular Ca2+ activity. This integrated photonic approach for imaging and controlling the release of large dense core granules provides exquisite cellular selectivity and should facilitate future studies of stimulus-secretion coupling and paracrine signaling in secretory cells. PMID:25572404

  5. Identification of agents that promote endoplasmic reticulum stress using an assay that monitors luciferase secretion

    PubMed Central

    Doudican, Nicole A.; Wen, Shih Ya; Mazumder, Amitabha; Orlow, Seth J.

    2015-01-01

    Disruption of protein processing in the secretory pathway is a measurable hallmark of endoplasmic reticulum (ER) stress. Activation of ER stress-mediated pathways has been implicated in numerous diseases including cancer. To identify agents that induce ER stress, we established a screen for compounds that reduce secretion of the reporter protein Gaussia luciferase (GLUC). Given the clinically validated importance of targeting ER stress-mediated pathways in the treatment of multiple myeloma (MM), we used this hematological malignancy as a model for validating our screening system. From a screen of 2000 marketed drugs and natural compounds in KMS11 and ARP1 MM cells, we identified 97 agents that reduced GLUC secretion in both cell lines by at least 30%. In order to confirm inducers of ER stress, we applied a secondary screen that assessed splicing of the unfolded protein response (UPR) transcription factor XBP1. One agent, theaflavin-3,3′–digallate (TF-3), was chosen based on its history of safe human consumption and further validated through studies of ER stress-related pathways including the UPR and apoptosis. Given these promising results, this screen could be a useful tool to identify agents targeting ER stress-related mechanisms in other cellular systems wherein ER stress plays a role in disease etiology. PMID:24371212

  6. Coproduction of ethanol and glycerol.

    PubMed

    Gong, C S; Du, J X; Cao, N J; Tsao, G T

    2000-01-01

    Ethanol and glycerol are both metabolic products of yeasts. There are occasions when coproduction of both is considered desirable in industrial operations. In this article, we describe the potential of integrating the two processes. A LORRE Y8 yeast culture isolated from molasses is capable of efficient glycerol production from glucose, and a yeast Culture 1400 is an excellent producer of ethanol. By controlling the process conditions, the ratio of ethanol and glycerol production can be varied. PMID:10849818

  7. Direct methods for dynamic monitoring of secretions from single cells by capillary electrophoresis and microscopy with laser-induced native fluorescence detection

    SciTech Connect

    Tong, W.

    1997-10-08

    Microscale separation and detection methods for real-time monitoring of dynamic cellular processes (e.g., secretion) by capillary electrophoresis (CE) and microscopic imaging were developed. Ultraviolet laser-induced native fluorescence (LINF) provides simple, sensitive and direct detection of neurotransmitters and proteins without any derivatization. An on-column CE-LINF protocol for quantification of the release from single cell was demonstrated. Quantitative measurements of both the amount of insulin released from and the amount remaining in the cell ({beta}TC3) were achieved simultaneously. Secretion of catecholamines (norepinephrine (NE) and epinephrine (E)) from individual bovine adrenal chromaffin cells was determined using the on-column CE-LINF. Direct visualization of the secretion process of individual bovine adrenal chromaffin cells was achieved by LINF imaging microscopy with high temporal and spatial resolution. The secretion of serotonin from individual leech Retzius neurons was directly characterized by LINF microscopy with high spatial resolution.

  8. Boron bridging of rhamnogalacturonan-II, monitored by gel electrophoresis, occurs during polysaccharide synthesis and secretion but not post-secretion.

    PubMed

    Chormova, Dimitra; Messenger, David J; Fry, Stephen C

    2014-02-01

    The cell-wall pectic domain rhamnogalacturonan-II (RG-II) is cross-linked via borate diester bridges, which influence the expansion, thickness and porosity of the wall. Previously, little was known about the mechanism or subcellular site of this cross-linking. Using polyacrylamide gel electrophoresis (PAGE) to separate monomeric from dimeric (boron-bridged) RG-II, we confirmed that Pb(2+) promotes H3 BO3 -dependent dimerisation in vitro. H3 BO3 concentrations as high as 50 mm did not prevent cross-linking. For in-vivo experiments, we successfully cultured 'Paul's Scarlet' rose (Rosa sp.) cells in boron-free medium: their wall-bound pectin contained monomeric RG-II domains but no detectable dimers. Thus pectins containing RG-II domains can be held in the wall other than via boron bridges. Re-addition of H3 BO3 to 3.3 μm triggered a gradual appearance of RG-II dimer over 24 h but without detectable loss of existing monomers, suggesting that only newly synthesised RG-II was amenable to boron bridging. In agreement with this, Rosa cultures whose polysaccharide biosynthetic machinery had been compromised (by carbon starvation, respiratory inhibitors, anaerobiosis, freezing or boiling) lost the ability to generate RG-II dimers. We conclude that RG-II normally becomes boron-bridged during synthesis or secretion but not post-secretion. Supporting this conclusion, exogenous [(3) H]RG-II was neither dimerised in the medium nor cross-linked to existing wall-associated RG-II domains when added to Rosa cultures. In conclusion, in cultured Rosa cells RG-II domains have a brief window of opportunity for boron-bridging intraprotoplasmically or during secretion, but secretion into the apoplast is a point of no return beyond which additional boron-bridging does not readily occur. PMID:24320597

  9. Boron bridging of rhamnogalacturonan-II, monitored by gel electrophoresis, occurs during polysaccharide synthesis and secretion but not post-secretion

    PubMed Central

    Chormova, Dimitra; Messenger, David J; Fry, Stephen C

    2014-01-01

    The cell-wall pectic domain rhamnogalacturonan-II (RG-II) is cross-linked via borate diester bridges, which influence the expansion, thickness and porosity of the wall. Previously, little was known about the mechanism or subcellular site of this cross-linking. Using polyacrylamide gel electrophoresis (PAGE) to separate monomeric from dimeric (boron-bridged) RG-II, we confirmed that Pb2+ promotes H3BO3-dependent dimerisation in vitro. H3BO3 concentrations as high as 50 mm did not prevent cross-linking. For in-vivo experiments, we successfully cultured ‘Paul's Scarlet’ rose (Rosa sp.) cells in boron-free medium: their wall-bound pectin contained monomeric RG-II domains but no detectable dimers. Thus pectins containing RG-II domains can be held in the wall other than via boron bridges. Re-addition of H3BO3 to 3.3 μm triggered a gradual appearance of RG-II dimer over 24 h but without detectable loss of existing monomers, suggesting that only newly synthesised RG-II was amenable to boron bridging. In agreement with this, Rosa cultures whose polysaccharide biosynthetic machinery had been compromised (by carbon starvation, respiratory inhibitors, anaerobiosis, freezing or boiling) lost the ability to generate RG-II dimers. We conclude that RG-II normally becomes boron-bridged during synthesis or secretion but not post-secretion. Supporting this conclusion, exogenous [3H]RG-II was neither dimerised in the medium nor cross-linked to existing wall-associated RG-II domains when added to Rosa cultures. In conclusion, in cultured Rosa cells RG-II domains have a brief window of opportunity for boron-bridging intraprotoplasmically or during secretion, but secretion into the apoplast is a point of no return beyond which additional boron-bridging does not readily occur. PMID:24320597

  10. Rotation of ultrasonically levitated glycerol drops

    NASA Technical Reports Server (NTRS)

    Biswas, A.; Leung, E. W.; Trinh, E. H.

    1991-01-01

    Ultrasonic levitation is used to suspend single millimeter-size glycerol drops in a rectangular chamber. Audio-frequency laterally standing waves set up in the chamber are used to torque the suspended drops. The shape evolution of the drop under the combined effect of centrifugal forces and the acoustic radiation stress, along with its angular velocity are monitored, using video imaging and light scattering techniques. The results show good qualitative agreement with the theoretically predicted shape evolution as a function of angular velocity.

  11. A fluorescent lipid analogue can be used to monitor secretory activity and for isolation of mammalian secretion mutants.

    PubMed Central

    Ktistakis, N T; Kao, C Y; Wang, R H; Roth, M G

    1995-01-01

    The use of reporter proteins to study the regulation of secretion has often been complicated by posttranslational processing events that influence the secretion of certain proteins, but are not part of the cellular mechanisms that specifically regulate secretion. This has been a particular limitation for the isolation of mammalian secretion mutants, which has typically been a slow process. To provide a reporter of secretory activity independent of protein processing events, cells were labeled with the fluorescent lipid analogue C5-DMB-ceramide (ceramide coupled to the fluorophore boron dipyrromethene difluoride) and its secretion was followed by fluorescence microscopy and fluorescence-activated cell sorting. Brefeldin A, which severely inhibits secretion in Chinese hamster ovary cells, blocked secretion of C5-DMB-ceramide. At high temperature, export of C5-DMB-ceramide was inhibited in HRP-1 cells, which have a conditional defect in secretion. Using C5-DMB-ceramide as a reporter of secretory activity, several different pulse-chase protocols were designed that selected mutant Chinese hamster ovary cells that were resistant to the drug brefeldin A and others that were defective in the transport of glycoproteins to the cell surface. Mutant cells of either type were identified in a mutagenized population at a frequency of 10(-6). Thus, the fluorescent lipid C5-DMB-ceramide can be used as a specific marker of secretory activity, providing an efficient, general approach for isolating mammalian cells with defects in the secretory pathway. Images PMID:7787242

  12. Characterization of crude glycerol from biodiesel plants.

    PubMed

    Hu, Shengjun; Luo, Xiaolan; Wan, Caixia; Li, Yebo

    2012-06-13

    Characterization of crude glycerol is very important to its value-added conversion. In this study, the physical and chemical properties of five biodiesel-derived crude glycerol samples were determined. Three methods, including iodometric-periodic acid method, high performance liquid chromatography (HPLC), and gas chromatography (GC), were shown to be suitable for the determination of glycerol content in crude glycerol. The compositional analysis of crude glycerol was successfully achieved by crude glycerol fractionation and characterization of the obtained fractions (aqueous and organic) using titrimetric, HPLC, and GC analyses. The aqueous fraction consisted mainly of glycerol, methanol, and water, while the organic fraction contained fatty acid methyl esters (FAMEs), free fatty acids (FFAs), and glycerides. Despite the wide variations in the proportion of their components, all raw crude glycerol samples were shown to contain glycerol, soap, methanol, FAMEs, water, glycerides, FFAs, and ash. PMID:22612334

  13. Glycerol production of various strains of saccharomyces

    SciTech Connect

    Radler, F.; Schuetz, H.

    1982-01-01

    The quantity of glycerol as principal by-product of the alcoholic fermentation depends to a large extent on the yeast strain. Different strains of Saccharomyces cerevisiae were found to form amounts of glycerol varying between 4.2 to 10.4 g/L. The formation of glycerol is regarded as a result of the competition between alcohol dehydrogenase and glycerol-3-phosphate dehydrogenase that compete for the reduced coenzyme NADH/sub 2/. High and low glycerol forming yeast strains showed large differences in the activity of glycerol-3-phosphate dehydrogenase and only small variation in the activity of alcohol dehydrogenase. The total amount of glycerol formed was also influenced by amino acids. In thiamine deficient media a decrease in glycerol formation was observed. Experiments indicate a correlation between the formation of acetaldehyde and glycerol and the production of cell mass that may be of practical interest. (Refs. 12).

  14. Monitoring human neutrophil granule secretion by flow cytometry: secretion and membrane potential changes assessed by light scatter and a fluorescent probe of membrane potential

    SciTech Connect

    Fletcher, M.P.; Seligmann, B.E.

    1985-04-01

    Purified human peripheral blood polymorphonuclear neutrophils (PMN) were incubated at 37 degrees C with the fluorescent membrane potential sensitive cyanine dye di-O-C(5)(3) and exposed to a number of stimulatory agents (N-formylmethionylleucylphenylalanine (FMLP), cytochalasin B (cyto B) + FMLP, phorbol myristate acetate (PMA). Flow cytometry was utilized to measure changes in forward light scatter (FS), orthogonal light scatter (90 degrees-SC), and fluorescence intensity of individual cells over time. A saturating (10(-6) M) dose of FMLP lead to a significant increase in the cells' FS without a change in 90 degrees-SC as well as a heterogeneous loss of di-O-C(5)(3) fluorescence. PMA (100 ng/ml) also caused an increase in FS but a uniform loss of dye fluorescence by all cells (apparent depolarization). Cyto B + FMLP produced an increase in FS, a marked loss of 90 degrees-SC, and a uniform loss of fluorescence. Secretion experiments under identical incubation conditions indicated a significantly positive relationship between loss of enzyme markers or cell granularity and orthogonal light scatter (r . 0.959, 0.998, and 0.989 for loss of 90 degrees-SC vs lysozyme, beta-glucuronidase, and granularity index, respectively). Flow cytometric light scatter measurements may yield important information on the extent of prior cell degranulation or activation.

  15. Identifying plasma glycerol concentration associated with urinary glycerol excretion in trained humans.

    PubMed

    Nelson, Jeff L; Harmon, Molly E; Robergs, Robert A

    2011-11-01

    Glycerol has been used as a means to legitimately hyperhydrate the body in an attempt to offset the deleterious effects of dehydration. It has the potential to mask blood doping practices and as a result has been added to the WADA prohibited substance list. The purpose of this study was to identify the plasma glycerol concentration coinciding with urinary glycerol excretion. Twelve healthy, trained male subjects completed five separate trials under resting conditions. For each trial, subjects consumed a different glycerol dose (0.025, 0.05, 0.10, 0.15, or 0.20 g glycerol/kg LBM) of a 5% glycerol solution in order to determine at what plasma glycerol concentration an increase in urine glycerol concentration becomes apparent. Based on regression analysis, plasma glycerol concentrations > 0.327 ± 0.190 mmol/L and a glycerol dose > 0.032 ± 0.010 g glycerol/kg LBM would be associated with urinary glycerol excretion. There were significant linear relationships between peak plasma glycerol concentration and time to reach peak plasma glycerol concentration to the ingested glycerol doses. Our findings illustrate the importance of considering the effect of urinary glycerol excretion on legitimate hyperhydration regimens as well as suggesting that it is possible to detect surreptitious use of glycerol as a masking agent through urinary analysis. PMID:22080901

  16. Glycerol inhibition of ruminal lipolysis in vitro

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Supplemental glycerol inhibits rumen lipolysis, a prerequisite for rumen biohydrogenation, which is responsible for the saturation of dietary fatty acids consumed by ruminant animals. Feeding excess glycerol, however, adversely affects dry matter digestibility. To more clearly define the effect of...

  17. Glycerol clearance in alcoholic liver disease.

    PubMed Central

    Johnston, D G; Alberti, K G; Wright, R; Blain, P G

    1982-01-01

    Glycerol clearance was studied by a primed dose-constant infusion technique in 14 patients with alcoholic liver disease and six normal control subjects. Fasting blood glycerol concentrations were raised in the alcoholic subjects (0.09 +/- 0.01 vs 0.06 +/- 0.01 mumol/l, p less than 0.05) and glycerol clearance was impaired (24.5 +/- 1.9 vs 37.5 +/- 3.2 ml/kg/min, p less than 0.005). Endogenous production rate of glycerol and distribution space at steady state were similar in alcoholic and control subjects. The metabolic clearance rate of glycerol correlated negatively with basal glycerol concentrations. Thus tissue uptake of glycerol is impaired in liver disease. As glycerol is metabolised primarily in the liver by conversion to glucose, these data suggest a defect of gluconeogenesis in alcoholic liver disease. PMID:7076002

  18. Antioxidant properties of feruloyl glycerol derivatives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The natural plant components, 1-feruloyl-sn-glycerol (FG) and 1,3-diferuloyl-sn-glycerol (F2G), were synthesized by the enzymatic esterification of glycerol and soybean oil mono- and diacylglycerols, respectively, with ethyl ferulate. The isolated FG and F2G were examined for their antioxidant acti...

  19. Kinetics of cinnamoyl glycerol formation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The esterifications of glycerol with cinnamic acid, 2-methoxy cinnamic acid, and 4-methoxy cinnamic acid were investigated in batch reactions. Conversions of over 50% were achieved for cinnamic acid and 4-methoxy cinnamic acid within 8 hours. After 24 hours conversions of over 80% were obtained fo...

  20. Esterification of glycerol from biodiesel production to glycerol carbonate in non-catalytic supercritical dimethyl carbonate.

    PubMed

    Ilham, Zul; Saka, Shiro

    2016-01-01

    Conversion of glycerol from biodiesel production to glycerol carbonate was studied by esterification with dimethyl carbonate in a non-catalytic supercritical condition. It was found that in a non-catalytic supercritical condition, glycerol at higher purity gave higher yield of glycerol carbonate at 98 wt% after reaction at 300 °C/20-40 MPa/15 min. The yield of glycerol carbonate was observed to increase with molar ratio, temperature, pressure and time until a certain equilibrium limit. The existence of impurities such as water and remnants of alkaline catalyst in crude glycerol will direct the reaction to produce glycidol. Although impurities might not be desirable, the non-catalytic supercritical dimethyl carbonate could be an alternative method for conversion of glycerol from biodiesel production to value-added glycerol carbonate.Graphical abstractPlausible reaction scheme for conversion of glycerol to glycerol carbonate in non-catalytic supercritical dimethyl carbonate. PMID:27386367

  1. Blockade of MUC1 expression by glycerol guaiacolate inhibits proliferation of human breast cancer cells.

    PubMed

    Smith, J S; Colon, J; Madero-Visbal, R; Isley, B; Konduri, S D; Baker, C H

    2010-10-01

    We sought to determine whether administration of glycerol guaiacolate at an optimal biological dose inhibits human breast cancer cell growth. Human breast cancer MCF-7 and ZR-75-1 cells were treated with glycerol guaiacolate and the therapeutic efficacy and biological activity of this drug was investigated on breast cancer cell growth. MCF-7 cells were injected into the mammary fat pad of overectamized female athymic nude mice. Ten days later, animals were treated with daily intraperitoneal injections of glycerol guaiacolate for six weeks. Tumor size and volume was monitored and immunohistochemistry analysis on MUC1, p21 and ki-67 was performed. Glycerol guaiacolate decreased breast cancer cell growth in a dose-dependent manner, decreased cell migration, and caused G1 cell cycle arrest. Our results demonstrate that glycerol guaiacolate inhibits MUC1 protein and mRNA expression levels and significantly increased p21 expression in human breast cancer cells as well as induced PARP cleavage. Similarly, glycerol guaiacolate inhibited breast tumor growth in vivo as well as enhanced p21 expression and decreased breast tumor cell proliferation (ki-67 expression). Collectively, our results demonstrate that glycerol guaiacolate decreased MUC1 expression and enhanced cell growth inhibition by inducing p21 expression in breast cancer cells. These findings suggest that glycerol guaiacolate may provide a novel and effective approach for the treatment of human breast cancer. PMID:21184665

  2. Mathematical modeling of glycerol biotransformation

    NASA Astrophysics Data System (ADS)

    Popova-Krumova, Petya; Yankova, Sofia; Ilieva, Biliana

    2013-12-01

    A method for mathematical modeling of glycerol biotransformation by Klebsiella oxytoca is presented. Glycerol is a renewable resource for it is formed as a by-product during biodiesel production. Because of its large volume production, it seems to be a good idea to develop a technology that converts this waste into products of high value (1, 3-Propanediol; 2, 3-Butanediol). The kinetic model of this process consists of many equations and parameters. The minimization of the least square function will be used for model parameters identification. In cases of parameters identification in multiparameter models the minimization of the least square function is very difficult because it is multiextremal. This is the main problem in the multiextremal function minimization which will be solved on the base a hierarchical approach, using a polynomial approximation of the experimental data.

  3. Spatiotemporal monitoring of the antibiome secreted by Bacillus biofilms on plant roots using MALDI mass spectrometry imaging.

    PubMed

    Debois, Delphine; Jourdan, Emmanuel; Smargiasso, Nicolas; Thonart, Philippe; De Pauw, Edwin; Ongena, Marc

    2014-05-01

    Some soil Bacilli living in association with plant roots can protect their host from infection by pathogenic microbes and are therefore being developed as biological agents to control plant diseases. The plant-protective activity of these bacteria has been correlated with the potential to secrete a wide array of antibiotic compounds upon growth as planktonic cells in isolated cultures under laboratory conditions. However, in situ expression of these antibiotics in the rhizosphere where bacterial cells naturally colonize root tissues is still poorly understood. In this work, we used matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) to examine spatiotemporal changes in the secreted antibiome of Bacillus amyloliquefaciens developing as biofilms on roots. Nonribosomal lipopeptides such as the plant immunity elicitor surfactin or the highly fungitoxic iturins and fengycins were readily produced albeit in different time frames and quantities in the surrounding medium. Interestingly, tandem mass spectrometry (MS/MS) experiments performed directly from the gelified culture medium also allowed us to identify a new variant of surfactins released at later time points. However, no other bioactive compounds such as polyketides were detected at any time, strongly suggesting that the antibiome expressed in planta by B. amyloliquefaciens does not reflect the vast genetic arsenal devoted to the formation of such compounds. This first dynamic study reveals the power of MALDI MSI as tool to identify and map antibiotics synthesized by root-associated bacteria and, more generally, to investigate plant-microbe interactions at the molecular level. PMID:24712753

  4. Selective glycerol oxidation by electrocatalytic dehydrogenation.

    PubMed

    Kim, Hyung Ju; Lee, Jechan; Green, Sara K; Huber, George W; Kim, Won Bae

    2014-04-01

    This study demonstrates that an electrochemical dehydrogenation process can be used to oxidize glycerol to glyceraldehyde and glyceric acid even without using stoichiometric chemical oxidants. A glyceric acid selectivity of 87.0 % at 91.8 % glycerol conversion was obtained in an electrocatalytic batch reactor. A continuous-flow electrocatalytic reactor had over an 80 % high glyceric acid selectivity at 10 % glycerol conversion, as well as greater reaction rates than either an electrocatalytic or a conventional catalytic batch reactor. PMID:24664518

  5. Glycerol-3-phosphatase of Corynebacterium glutamicum.

    PubMed

    Lindner, Steffen N; Meiswinkel, Tobias M; Panhorst, Maren; Youn, Jung-Won; Wiefel, Lars; Wendisch, Volker F

    2012-06-15

    Formation of glycerol as by-product of amino acid production by Corynebacterium glutamicum has been observed under certain conditions, but the enzyme(s) involved in its synthesis from glycerol-3-phosphate were not known. It was shown here that cg1700 encodes an enzyme active as a glycerol-3-phosphatase (GPP) hydrolyzing glycerol-3-phosphate to inorganic phosphate and glycerol. GPP was found to be active as a homodimer. The enzyme preferred conditions of neutral pH and requires Mg²⁺ or Mn²⁺ for its activity. GPP dephosphorylated both L- and D-glycerol-3-phosphate with a preference for the D-enantiomer. The maximal activity of GPP was estimated to be 31.1 and 1.7 U mg⁻¹ with K(M) values of 3.8 and 2.9 mM for DL- and L-glycerol-3-phosphate, respectively. For physiological analysis a gpp deletion mutant was constructed and shown to lack the ability to produce detectable glycerol concentrations. Vice versa, gpp overexpression increased glycerol accumulation during growth in fructose minimal medium. It has been demonstrated previously that intracellular accumulation of glycerol-3-phosphate is growth inhibitory as shown for a recombinant C. glutamicum strain overproducing glycerokinase and glycerol facilitator genes from E. coli in media containing glycerol. In this strain, overexpression of gpp restored growth in the presence of glycerol as intracellular glycerol-3-phosphate concentrations were reduced to wild-type levels. In C. glutamicum wild type, GPP was shown to be involved in utilization of DL-glycerol-3-phosphate as source of phosphorus, since growth with DL-glycerol-3-phosphate as sole phosphorus source was reduced in the gpp deletion strain whereas it was accelerated upon gpp overexpression. As GPP homologues were found to be encoded in the genomes of many other bacteria, the gpp homologues of Escherichia coli (b2293) and Bacillus subtilis (BSU09240, BSU34970) as well as gpp1 from the plant Arabidosis thaliana were overexpressed in E. coli MG1655 and

  6. Glycerol inhibition of ruminal lipolysis in vitro.

    PubMed

    Edwards, H D; Anderson, R C; Miller, R K; Taylor, T M; Hardin, M D; Smith, S B; Krueger, N A; Nisbet, D J

    2012-09-01

    Supplemental glycerol inhibits rumen lipolysis, a prerequisite for rumen biohydrogenation, which is responsible for the saturation of dietary fatty acids consumed by ruminant animals. Feeding excess glycerol, however, adversely affects dry matter digestibility. To more clearly define the effect of supplemental glycerol on rumen lipolysis, mixed populations of ruminal bacteria were incubated with 6 or 20% glycerol (vol/vol). After 48-h anaerobic incubation of mixed culture rumen fluid, rates of free fatty acid production (nmol/mL per h) for the 6 and 20% glycerol-supplemented samples were decreased by 80 and 86%, respectively, compared with rates from nonsupplemented control cultures (12.4±1.0; mean ± SE). Conversely, assay of the prominent ruminal lipase-producing bacteria Anaerovibrio lipolyticus 5S, Butyrivibrio fibrisolvens 49, and Propionibacterium species avidum and acnes revealed no effect of 2 or 10% (vol/vol) added glycerol on lipolytic activity by these organisms. Supplementing glycerol at 6% on a vol/vol basis, equivalent to supplementing glycerol at approximately 8 to 15% of diet dry matter, effectively reduced lipolysis. However, the mechanism of glycerol inhibition of ruminal lipolysis remains to be demonstrated. PMID:22916923

  7. Calibrating the glycerol dialkyl glycerol tetraether temperature signal in speleothems

    NASA Astrophysics Data System (ADS)

    Blyth, Alison J.; Schouten, Stefan

    2013-05-01

    Palaeotemperature proxies based on glycerol dialkyl glycerol tetraethers (GDGTs) lipids have been established for marine and lacustrine environments, but there has been relatively little study of their application in speleothems. In this study we analyse the GDGT content of 33 speleothem samples from 16 different sites around the globe, and test whether proxies based on isoprenoid tetraethers (TEX86) or branched tetraethers (MBT/CBT) are correlated with measured surface and cave mean annual air temperature (MAT). The results show that the TEX86 has a strong relationship with measured temperature (r2 = 0.78, standard error of the estimate 2.3 °C, when calibrated with surface MAT). Furthermore, the MBT/CBT also showed a significant relationship with temperature (r2 = 0.73, standard error of the estimate 2.7 °C, when calibrated with surface MAT). Some issues remain requiring future work, in particular the development of a larger calibration sample set with measured cave temperature data, and the investigation of controls other than temperature on GDGT distribution, but overall the results indicate that GDGT based proxies derived from speleothems may be highly viable new methods for reconstructing continental palaeotemperatures.

  8. Comparative analysis of lymphocyte activation marker expression and cytokine secretion profile in stimulated human peripheral blood mononuclear cell cultures: an in vitro model to monitor cellular immune function.

    PubMed

    Reddy, Manjula; Eirikis, Edward; Davis, Cuc; Davis, Hugh M; Prabhakar, Uma

    2004-10-01

    Activation of lymphocytes is a complex, yet finely regulated cascade of events that results in the expression of cytokine receptors, production and secretion of cytokines and expression of several cell surface molecules that eventually lead to divergent immune responses. Assessing the qualitative and quantitative nature of lymphocyte function following immunotherapy provides valuable information about the immune responses mediated by a therapeutic agent. To facilitate evaluation of the immunomodulatory activity of therapeutic agents, we have established a platform of in vitro immunoassays with normal human peripheral blood mononuclear cells (PBMCs) treated with several polyclonal activators that are known to exhibit different modes of action. We evaluated the kinetics of cell surface marker expression and cytokine release from PBMCs stimulated in parallel with various activating agents over a time course. These stimulating agents induced early (CD69 and CD71) and late (CD25 and HLA-DR) activation markers to varying antigen densities, indicated different cytokine profiles, and showed differential inhibition with dexamethasone (DEX), an inhibitor of early signaling events. Based on the association or correlation of the kinetics of activation marker expression and secreted cytokines, the results of our study indicate the appropriate time points for the simultaneous measurement of both these activation products. This study defines the kinetics for both measures of T cell activation and provides a comprehensive review with various polyclonal activators that can serve as a reference for monitoring lymphocyte function in clinical study samples. PMID:15541283

  9. Atlantic cod (Gadus morhua) larvae can biosynthesis phospholipid de novo from 2-oleoyl-glycerol and glycerol precursors.

    PubMed

    Li, Keshuai; Olsen, Rolf Erik; Østensen, Mari-Ann; Altin, Dag; Kjørsvik, Elin; Olsen, Yngvar

    2016-02-01

    The dietary requirement of phospholipid (PL) of fish larvae has been suggested to originate in an inefficient ability for de novo biosynthesis of PL based on dietary triacylglycerol (TAG). The main objective of the present study was to investigate whether cod larvae could synthesis PL from sn-2-monoacylglycerol (2-MAG) and glycerol precursors. A tube feeding method was used to deliver equal molar aliquots of 2-oleoyl-[1,2,3-(3)H]glycerol and [U-(14)C] glycerol together with bovine serum albumin (BSA) bound 16:0 (palmitic acid) and 22:6n-3 (docosahexaenoic acid, DHA), with or without choline chloride to the foregut of anesthetized cod larvae and thereafter monitoring the metabolism of these components in the larvae through 4 h following injection. Our results showed that both 2-MAG and glycerol precursors contributed to the de novo synthesis of phosphatidylcholine (PC) and the 2-MAG pathway predominated over the G-3-P (glycerol-3-phosphate) pathway in the synthesis of TAG and PC. The molecular ratio of PC/TAG obtained from the 2-MAG and the G-3-P pathways was 0.44-0.74 and 1.02-2.06 within the first hour of tube feeding, suggesting they might have comparable biosynthesis ability of PC and TAG under the conditions of the present study. Furthermore, supplementation of choline chloride significantly increased PC/TAG ratio (p < 0.05) for both pathways. However, further studies are needed to quantify the enzyme activity involved in the CDP-choline (cytidine diphosphate choline) pathway, and the function of choline either in simulating PC synthesis or TAG catabolism or both needs further investigation. PMID:26349454

  10. Renal handling of drugs in renal failure. I: Differential effects of uranyl nitrate- and glycerol-induced acute renal failure on renal excretion of TEAB and PAH in rats

    SciTech Connect

    Lin, J.H.; Lin, T.H.

    1988-09-01

    Two etiologically different models of experimental acute renal failure were induced in rats by administration of either glycerol or uranyl nitrate. Both compounds caused a substantial decrease in the glomerular filtration rate (GFR) and the net tubular secretion of tetraethylammonium bromide (TEAB) and para-aminohippuric acid (PAH). The degree of renal impairment induced by uranyl nitrate and glycerol appeared to be dose related. Deprivation of drinking water 24 hr before the administration of glycerol potentiated the renal damage. In uranyl nitrate-induced renal failure, the decline of the net tubular secretion for TEAB and PAH was not proportional to the decrease in GFR; the secretion process deteriorated faster than the GFR. For example, when 0.5 mg/kg uranyl nitrate was administered, GFR fell to approximately 65% of normal, whereas the net tubular secretion was decreased to 30% of normal. These results suggest that the tubular transport was preferentially affected by uranyl nitrate. In contrast, in glycerol-induced renal failure, the decline of TEAB secretion fell in a parallel fashion with the GFR, suggesting that the glomeruli and the proximal tubules were equally damaged by glycerol. However, in this latter model, the decline of PAH secretion did not parallel the decrease in GFR, contradicting the proposal that glycerol affects equally the glomeruli and the proximal tubules. This discrepancy may be due to the selective competitive inhibition of PAH secretion by the accumulation of naturally occurring organic acids.

  11. Probing protein stabilization by glycerol using electrospray mass spectrometry.

    PubMed

    Grandori, R; Matecko, I; Mayr, P; Müller, N

    2001-08-01

    This study shows that electrospray ionization mass spectrometry (ESI-MS), combined with a heated turbo ion-spray interface, allows monitoring protein stabilization by glycerol in solution. Measurements obtained with the two proteins lysozyme and cytochrome c are presented. The observed mass-to-charge (m/z) distributions reveal the stabilizing effect of the additive on the protein conformations against temperature and acid-induced unfolding, as well as against denaturation by acetonitrile. The data obtained with lysozyme allow detection of minor conformational changes upon glycerol addition to the native protein, and suggest that the protein structure in the presence of the additive is slightly compressed compared with its state in water. This result corroborates previous evidence obtained by nuclear magnetic resonance. It is also shown that analysis of the m/z distributions obtained by ESI-MS can lead to detection of partially folded and partially populated states in protein samples. PMID:11523091

  12. RUMINAL FERMENTATION OF PROPYLENE GLYCOL AND GLYCEROL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bovine rumen fluid was fermented anaerobically with 25 mM R-propylene glycol, S-propylene glycol, or glycerol added. After 24 h all of the propylene glycol enantiomers and approximately 80% of the glycerol were metabolized. Acetate, propionate, butyrate, valerate, and caproate concentrations, in dec...

  13. Glycerol citrate polyesters produced through microwave heating

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The influence of various heating methods without catalysis to prepare copolyesters from citric acid:glycerol blends were studied. In the presence of short term microwave treatments, i.e., 60 sec at 1200 W, blends of glycerol and citric acid invariably formed solid amorphous copolyesters. Fourier tra...

  14. Thermal and physical characterization of glycerol polyesters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glycerol polyesters were prepared by the condensation of glycerol and adipic acid, azelaic acid, sebacic acid, or suberic acids. After 48 hours at 125 deg C the polymers were clear and flexible. Samples of the reaction mixtures were analyzed by modulated differential scanning calorimetry to identi...

  15. Correlation spectroscopy applied to glycerol polyester spectra

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The recent development of glycerol polyesters for use as controlled release matrix materials in the nutraceuticals and pharmaceuticals industries presented a unique opportunity to apply correlation spectroscopy. In a typical formulation the glycerol is reacted with a polyfunctional acid such as citr...

  16. Formulation and Applications of Glycerol Polymers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increased production of biodiesel in the U.S. and Europe during the past several years has created an oversupply of glycerol, creating lower domestic profitability. In addition, increased petroleum prices have driven up the cost of synthetic polymers made from petrochemicals. Glycerol can be polym...

  17. From ether to acid: A plausible degradation pathway of glycerol dialkyl glycerol tetraethers

    NASA Astrophysics Data System (ADS)

    Liu, Xiao-Lei; Birgel, Daniel; Elling, Felix J.; Sutton, Paul A.; Lipp, Julius S.; Zhu, Rong; Zhang, Chuanlun; Könneke, Martin; Peckmann, Jörn; Rowland, Steven J.; Summons, Roger E.; Hinrichs, Kai-Uwe

    2016-06-01

    Glycerol dialkyl glycerol tetraethers (GDGTs) are ubiquitous microbial lipids with extensive demonstrated and potential roles as paleoenvironmental proxies. Despite the great attention they receive, comparatively little is known regarding their diagenetic fate. Putative degradation products of GDGTs, identified as hydroxyl and carboxyl derivatives, were detected in lipid extracts of marine sediment, seep carbonate, hot spring sediment and cells of the marine thaumarchaeon Nitrosopumilus maritimus. The distribution of GDGT degradation products in environmental samples suggests that both biotic and abiotic processes act as sinks for GDGTs. More than a hundred newly recognized degradation products afford a view of the stepwise degradation of GDGT via (1) ether bond hydrolysis yielding hydroxyl isoprenoids, namely, GDGTol (glycerol dialkyl glycerol triether alcohol), GMGD (glycerol monobiphytanyl glycerol diether), GDD (glycerol dibiphytanol diether), GMM (glycerol monobiphytanol monoether) and bpdiol (biphytanic diol); (2) oxidation of isoprenoidal alcohols into corresponding carboxyl derivatives and (3) chain shortening to yield C39 and smaller isoprenoids. This plausible GDGT degradation pathway from glycerol ethers to isoprenoidal fatty acids provides the link to commonly detected head-to-head linked long chain isoprenoidal hydrocarbons in petroleum and sediment samples. The problematic C80 to C82 tetraacids that cause naphthenate deposits in some oil production facilities can be generated from H-shaped glycerol monoalkyl glycerol tetraethers (GMGTs) following the same process, as indicated by the distribution of related derivatives in hydrothermally influenced sediments.

  18. Biosynthesis of glycerol carbonate from glycerol by lipase in dimethyl carbonate as the solvent.

    PubMed

    Lee, Kyung Hwa; Park, Chang-Ho; Lee, Eun Yeol

    2010-11-01

    Glycerol carbonate was synthesized from renewable glycerol and dimethyl carbonate using lipase in solvent-free reaction system in which excess dimethyl carbonate played as the reaction medium. A variety of lipases have been tested for their abilities to catalyze transesterification reaction, and Candida antartica lipase B and Novozyme 435 exhibited higher catalytic activities. The silica-coated glycerol with a 1:1 ratio was supplied to prevent two-phase formation between hydrophobic dimethyl carbonate and hydrophilic glycerol. Glycerol carbonate was successfully synthesized with more than 90% conversion from dimethyl carbonate and glycerol with a molar ratio of 10 using Novozyme 435-catalyzed transesterification at 70 °C. The Novozyme 435 [5% (w/w) and 20% (w/w)] and silica gel were more than four times recycled with good stability in a repeated batch operation for the solvent-free synthesis of glycerol carbonate. PMID:20502921

  19. Ethanolysis of rapeseed oil - distribution of ethyl esters, glycerides and glycerol between ester and glycerol phases.

    PubMed

    Cernoch, Michal; Hájek, Martin; Skopal, Frantisek

    2010-04-01

    The distribution of ethyl esters, triglycerides, diglycerides, monoglycerides, and glycerol between the ester and glycerol phase was investigated after the ethanolysis of rapeseed oil at various reaction conditions. The determination of these substances in the ester and glycerol phases was carried out by the GC method. The amount of ethyl esters in the glycerol phase was unexpectedly high and therefore the possibility of the reduction of this amount was investigated. The distribution coefficients and the weight distributions of each investigated substance were calculated and compared mutually. The distribution coefficients between the ester and glycerol phase increase in this sequence: glycerol, monoglycerides, diglycerides, ethyl esters, and triglycerides. Soaps and monoglycerides in the reaction mixture cause a worse separation of ethyl esters from the reaction mixture. The existence of a non-separable reaction mixture was observed also, and its composition was determined. PMID:20005094

  20. Efficient green methanol synthesis from glycerol

    NASA Astrophysics Data System (ADS)

    Haider, Muhammad H.; Dummer, Nicholas F.; Knight, David W.; Jenkins, Robert L.; Howard, Mark; Moulijn, Jacob; Taylor, Stuart H.; Hutchings, Graham J.

    2015-12-01

    The production of biodiesel from the transesterification of plant-derived triglycerides with methanol has been commercialized extensively. Impure glycerol is obtained as a by-product at roughly one-tenth the mass of the biodiesel. Utilization of this crude glycerol is important in improving the viability of the overall process. Here we show that crude glycerol can be reacted with water over very simple basic or redox oxide catalysts to produce methanol in high yields, together with other useful chemicals, in a one-step low-pressure process. Our discovery opens up the possibility of recycling the crude glycerol produced during biodiesel manufacture. Furthermore, we show that molecules containing at least two hydroxyl groups can be converted into methanol, which demonstrates some aspects of the generality of this new chemistry.

  1. Production of 3-Hydroxypropionaldehyde from Glycerol

    PubMed Central

    Slininger, Patricia J.; Bothast, Rodney J.; Smiley, Karl L.

    1983-01-01

    3-Hydroxypropionaldehyde is a precursor to acrolein, which can be used as an intermediate for making acrylic acid and a variety of other useful industrial chemicals. Conversion of glycerol, a renewable resource, to 3-hydroxypropionaldehyde was attempted via action of glycerol dehydrase isolated from Lactobacillus sp. strain NRRL B-1720. This method, however, was unsatisfactory because enzyme activity was lost within 60 to 90 min after the reaction initiation. Fermentation of glycerol by whole cells of Klebsiella pneumoniae NRRL B-199 in the presence of optimal semicarbazide hydrochloride proved more effective. Using this technique, glycerol solutions of 30 g/liter yielded 3-hydroxypropionaldehyde solutions of 13.1 g/liter. Thus, a conversion efficiency equal to 55% of the theoretical maximum was realized. PMID:16346353

  2. Glycerol induces reuterin production and decreases Escherichia coli population in an in vitro model of colonic fermentation with immobilized human feces.

    PubMed

    Cleusix, Valentine; Lacroix, Christophe; Vollenweider, Sabine; Le Blay, Gwenaëlle

    2008-01-01

    Lactobacillus reuteri ATCC 55730 is a probiotic strain that produces, in the presence of glycerol, reuterin, a broad-spectrum antimicrobial substance. This strain has been shown to prevent intestinal infections in vivo; however, its mechanisms of action, and more specifically whether reuterin production occurs within the intestinal tract, are not known. In this study, the effects of L. reuteri ATCC 55730 on intestinal microbiota and its capacity to secrete reuterin from glycerol in a novel in vitro colonic fermentation model were tested. Two reactors were inoculated with adult immobilized fecal microbiota and the effects of daily addition of L. reuteri into one of the reactors (c.10(8) CFU mL(-1)) without or with glycerol were tested on major bacterial populations and compared with addition of glycerol or reuterin alone. The addition of glycerol alone or with L. reuteri increased numbers of the Lactobacillus-Enterococcus group and decreased Escherichia coli. The addition of reuterin significantly and selectively decreased E. coli without affecting other bacterial populations. The observed decrease in E. coli concentration during the addition of glycerol (in presence or absence of L. reuteri) could be due to in situ reuterin production because 1,3-propanediol, a typical product of glycerol fermentation, was detected during the addition of glycerol. PMID:18028400

  3. Secret Places.

    ERIC Educational Resources Information Center

    Ridolfi, Kerry

    1997-01-01

    Argues that children are as deep as the ocean, with secret places inside of them waiting to be opened. Notes that it is powerful for students to learn they can make sense of the world through words, and describes inviting them into poetry as they read poetry, create poetry packets, and write and revise poems. (SR)

  4. Glycerol monooleate-blood interactions.

    PubMed

    Ericsson, Emma M; Faxälv, Lars; Weissenrieder, Anna; Askendal, Agneta; Lindahl, Tomas L; Tengvall, Pentti

    2009-01-01

    In the present study the initial blood compatibility of glycerol monooleate (GMO)-coated surfaces was evaluated after deposition to surfaces and in bulk. The model surface was silica onto which multiple layers of fibrinogen or human serum albumin (HSA) was immobilized. The protein-coated surfaces were subsequently dip-coated in GMO in ethanol and used for blood plasma and whole blood experiments. The characterization methods included null ellipsometry, scanning electron microscopy, imaging of coagulation, hemolysis test and whole blood coagulation time by free oscillation rheometry. The results showed a GMO film thickness of approximately 350 A (approximately 4 microg/cm(2)) upon dip-coating in ethanolic solution. A major part of the deposited layer detached in aqueous solutions, especially during shear conditions. The coagulation time on GMO was significantly prolonged compared to that on HSA coated silica. Whole blood tests showed that GMO is a very weak hemolytic agent. Deposited GMO detached easily from surfaces upon rinsing or shearing, although a stable layer with undefined phase structure and a thickness of 50-70 A remained on HSA and fibrinogen precoated surfaces. This indicates that GMO has stronger adhesive forces to its substrate compared to the cohesive forces acting within the bulk GMO. The ability of GMO to detach from itself and tentatively form micelles or lipid bilayers when subjected to flowing blood may be of use in extravascular applications. It is concluded that GMO results in weak blood activation, and the material may in spite of this be suitable in selected biomaterial applications, especially as a biosealant and in colloidal dispersions. PMID:18996684

  5. Synthesis of Glycerol Carbonate by Transesterification of Glycerol with Urea Over Zn/Al Mixed Oxide.

    PubMed

    Ryu, Young Bok; Baek, Jae Ho; Kim, Yangdo; Lee, Man Sig

    2015-01-01

    Reactions of glycerol carbonate using glycerol and urea have been carried out previously using ZnSO4 and ZnO catalysts, and high yields have been reported using ZnSO4 as catalyst. However, this salt is soluble in glycerol, and recycling of catalyst is difficult after the reaction. In this study, we prepared a mixed metal oxide catalyst using Zn and Al, and this catalyst consisted of a mixture of ZnO and ZnAl2O4. We confirmed the conversion of glycerol and the yield of glycerol carbonate of the amount of Al. As a result, we obtained a yield of 82.3% and a conversion of 82.7%. In addition we obtained high yield in recycling of catalyst. The yield of the glycerol carbonate increases with an increase of acid and base site of catalysts and the highest catalytic activity was obtained when acid/base ratio was approx. 1. From this result, we may conclude that the acid and base site density and ratio of catalysts were very important parameters in the synthesis of glycerol carbonate from urea and glycerol. PMID:26328352

  6. Radiometric assays for glycerol, glucose, and glycogen.

    PubMed

    Bradley, D C; Kaslow, H R

    1989-07-01

    We have developed radiometric assays for small quantities of glycerol, glucose and glycogen, based on a technique described by Thorner and Paulus (1971, J. Biol. Chem. 246, 3885-3894) for the measurement of glycerokinase activity. In the glycerol assay, glycerol is phosphorylated with [32P]ATP and glycerokinase, residual [32P]ATP is hydrolyzed by heating in acid, and free [32P]phosphate is removed by precipitation with ammonium molybdate and triethylamine. Standard dose-response curves were linear from 50 to 3000 pmol glycerol with less than 3% SD in triplicate measurements. Of the substances tested for interference, only dihydroxyacetone gave a slight false positive signal at high concentration. When used to measure glycerol concentrations in serum and in media from incubated adipose tissue, the radiometric glycerol assay correlated well with a commonly used spectrophotometric assay. The radiometric glucose assay is similar to the glycerol assay, except that glucokinase is used instead of glycerokinase. Dose response was linear from 5 to 3000 pmol glucose with less than 3% SD in triplicate measurements. Glucosamine and N-acetylglucosamine gave false positive signals when equimolar to glucose. When glucose concentrations in serum were measured, the radiometric glucose assay agreed well with hexokinase/glucose-6-phosphate dehydrogenase (H/GDH)-based and glucose oxidase/H2O2-based glucose assays. The radiometric method for glycogen measurement incorporates previously described isolation and digestion techniques, followed by the radiometric assay of free glucose. When used to measure glycogen in mouse epididymal fat pads, the radiometric glycogen assay correlated well with the H/GDH-based glycogen assay. All three radiometric assays offer several practical advantages over spectral assays. PMID:2817333

  7. Radiometric assays for glycerol, glucose, and glycogen

    SciTech Connect

    Bradley, D.C.; Kaslow, H.R. )

    1989-07-01

    We have developed radiometric assays for small quantities of glycerol, glucose and glycogen, based on a technique described by Thorner and Paulus for the measurement of glycerokinase activity. In the glycerol assay, glycerol is phosphorylated with (32P)ATP and glycerokinase, residual (32P)ATP is hydrolyzed by heating in acid, and free (32P)phosphate is removed by precipitation with ammonium molybdate and triethylamine. Standard dose-response curves were linear from 50 to 3000 pmol glycerol with less than 3% SD in triplicate measurements. Of the substances tested for interference, only dihydroxyacetone gave a slight false positive signal at high concentration. When used to measure glycerol concentrations in serum and in media from incubated adipose tissue, the radiometric glycerol assay correlated well with a commonly used spectrophotometric assay. The radiometric glucose assay is similar to the glycerol assay, except that glucokinase is used instead of glycerokinase. Dose response was linear from 5 to 3000 pmol glucose with less than 3% SD in triplicate measurements. Glucosamine and N-acetylglucosamine gave false positive signals when equimolar to glucose. When glucose concentrations in serum were measured, the radiometric glucose assay agreed well with hexokinase/glucose-6-phosphate dehydrogenase (H/GDH)-based and glucose oxidase/H2O2-based glucose assays. The radiometric method for glycogen measurement incorporates previously described isolation and digestion techniques, followed by the radiometric assay of free glucose. When used to measure glycogen in mouse epididymal fat pads, the radiometric glycogen assay correlated well with the H/GDH-based glycogen assay. All three radiometric assays offer several practical advantages over spectral assays.

  8. Enhanced cellulase production by Trichoderma harzianum by cultivation on glycerol followed by induction on cellulosic substrates.

    PubMed

    Delabona, Priscila da Silva; Lima, Deise Juliana; Robl, Diogo; Rabelo, Sarita Cândida; Farinas, Cristiane Sanchez; Pradella, José Geraldo da Cruz

    2016-05-01

    The use of glycerol obtained as an intermediate of the biodiesel manufacturing process as carbon source for microbial growth is a potential alternative strategy for the production of enzymes and other high-value bioproducts. This work evaluates the production of cellulase enzymes using glycerol for high cell density growth of Trichoderma harzianum followed by induction with a cellulosic material. Firstly, the influence of the carbon source used in the pre-culture step was investigated in terms of total protein secretion and fungal morphology. Enzymatic productivity was then determined for cultivation strategies using different types and concentrations of carbon source, as well as different feeding procedures (batch and fed-batch). The best strategy for cellulase production was then further studied on a larger scale using a stirred tank bioreactor. The proposed strategy for cellulase production, using glycerol to achieve high cell density growth followed by induction with pretreated sugarcane bagasse, achieved enzymatic activities up to 2.27 ± 0.37 FPU/mL, 106.40 ± 8.87 IU/mL, and 9.04 ± 0.39 IU/mL of cellulase, xylanase, and β-glucosidase, respectively. These values were 2 times higher when compared to the control experiments using glucose instead of glycerol. This novel strategy proved to be a promising approach for improving cellulolytic enzymes production, and could potentially contribute to adding value to biomass within the biofuels sector. PMID:26883662

  9. Glycerol-induced folding of unstructured disulfide-deficient lysozyme into a native-like conformation.

    PubMed

    Sakamoto, Keiko; Hirai, Ken-Ichi; Kitamura, Yoshiaki; Yamazaki, Kouta; Yusa, Mitsunobu; Tokunaga, Naoki; Doi, Gakuji; Noda, Yasuo; Tachibana, Hideki; Segawa, Shin-Ichi

    2009-08-01

    2SS[6-127,64-80] variant of lysozyme which has two disulfide bridges, Cys6-Cys127 and Cys64-Cys80, and lacks the other two disulfide bridges, Cys30-Cys115 and Cys76-Cys94, was quite unstructured in water, but a part of the polypeptide chain was gradually frozen into a native-like conformation with increasing glycerol concentration. It was monitored from the protection factors of amide hydrogens against H/D exchange. In solution containing various concentrations of glycerol, H/D exchange reactions were carried out at pH* 3.0 and 4 degrees C. Then, (1)H-(15)N-HSQC spectra of partially deuterated protein were measured in a quenching buffer for H/D exchange (95% DMSO/5% D(2)O mixture at pH* 5.5 adjusted with dichloroacetate). In a solution of 10% glycerol, the protection factors were nearly equal to 10 at most of residues. With increasing glycerol concentration, some selected regions were further protected, and their protection factors reached about a 1000 in 30% glycerol solution. The highly protected residues were included in A-, B-, and C-helices and beta3-strand, and especially centered on Ile 55 and Leu 56. In 2SS[6-127,64-80], long-range interactions were recovered due to the preferential hydration by glycerol in the hydrophobic box of the alpha-domain. Glycerol-induced recovering of the native-like structure is discussed from the viewpoint of molten globules growing with the protein folding. (c) 2009 Wiley Periodicals, Inc. Biopolymers 91: 665-675, 2009.This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com. PMID:19353641

  10. Catalytic glycerol steam reforming for hydrogen production

    NASA Astrophysics Data System (ADS)

    Dan, Monica; Mihet, Maria; Lazar, Mihaela D.

    2015-12-01

    Hydrogen production from glycerol by steam reforming combine two major advantages: (i) using glycerol as raw material add value to this by product of bio-diesel production which is obtained in large quantities around the world and have a very limited utilization now, and (ii) by implication of water molecules in the reaction the efficiency of hydrogen generation is increased as each mol of glycerol produces 7 mol of H2. In this work we present the results obtained in the process of steam reforming of glycerol on Ni/Al2O3. The catalyst was prepared by wet impregnation method and characterized through different methods: N2 adsorption-desorption, XRD, TPR. The catalytic study was performed in a stainless steel tubular reactor at atmospheric pressure by varying the reaction conditions: steam/carbon ratio (1-9), gas flow (35 ml/min -133 ml/min), temperature (450-650°C). The gaseous fraction of the reaction products contain: H2, CH4, CO, CO2. The optimum reaction conditions as resulted from this study are: temperature 550°C, Gly:H2O ratio 9:1 and Ar flow 133 ml/min. In these conditions the glycerol conversion to gaseous products was 43% and the hydrogen yield was 30%.

  11. Catalytic glycerol steam reforming for hydrogen production

    SciTech Connect

    Dan, Monica Mihet, Maria Lazar, Mihaela D.

    2015-12-23

    Hydrogen production from glycerol by steam reforming combine two major advantages: (i) using glycerol as raw material add value to this by product of bio-diesel production which is obtained in large quantities around the world and have a very limited utilization now, and (ii) by implication of water molecules in the reaction the efficiency of hydrogen generation is increased as each mol of glycerol produces 7 mol of H{sub 2}. In this work we present the results obtained in the process of steam reforming of glycerol on Ni/Al{sub 2}O{sub 3}. The catalyst was prepared by wet impregnation method and characterized through different methods: N{sub 2} adsorption-desorption, XRD, TPR. The catalytic study was performed in a stainless steel tubular reactor at atmospheric pressure by varying the reaction conditions: steam/carbon ratio (1-9), gas flow (35 ml/min -133 ml/min), temperature (450-650°C). The gaseous fraction of the reaction products contain: H{sub 2}, CH{sub 4}, CO, CO{sub 2}. The optimum reaction conditions as resulted from this study are: temperature 550°C, Gly:H{sub 2}O ratio 9:1 and Ar flow 133 ml/min. In these conditions the glycerol conversion to gaseous products was 43% and the hydrogen yield was 30%.

  12. Reduced catabolic protein expression in Clostridium butyricum DSM 10702 correlate with reduced 1,3-propanediol synthesis at high glycerol loading

    PubMed Central

    2014-01-01

    Higher initial glycerol loadings (620 mM) have a negative effect on growth and 1,3-propanediol (1,3-PDO) synthesis in Clostridium butyricum DSM 10702 relative to lower initial glycerol concentrations (170 mM). To help understand metabolic shifts associated with elevated glycerol, protein expression levels were quantified by LC/MS/MS analyses. Thirty one (31) proteins involved in conversion of glycerol to 1,3-PDO and other by-products were analyzed by multiple reaction monitoring (MRM). The analyses revealed that high glycerol concentrations reduced cell growth. The expression levels of most proteins in glycerol catabolism pathways were down-regulated, consistent with the slower growth rates observed. However, at high initial glycerol concentrations, some of the proteins involved in the butyrate synthesis pathways such as a putative ethanol dehydrogenase (CBY_3753) and a 3-hydroxybutyryl-CoA dehydrogenase (CBY_3045) were up-regulated in both exponential and stationary growth phases. Expression levels of proteins (CBY_0500, CBY_0501 and CBY_0502) involved in the reductive pathway of glycerol to 1,3-PDO were consistent with glycerol consumption and product concentrations observed during fermentation at both glycerol concentrations, and the molar yields of 1,3-PDO were similar in both cultures. This is the first report that correlates expression levels of glycerol catabolism enzymes with synthesis of 1,3-PDO in C. butyricum. The results revealed that significant differences in the expression of a small subset of proteins were observed between exponential and stationary growth phases at both low and high glycerol concentrations. PMID:25401066

  13. Bioconversion of glycerol to ethanol by a mutant Enterobacter aerogenes

    PubMed Central

    2012-01-01

    The main objective of this research is to develop, by adaptive evolution, mutant strains of Enterobacter aerogenes ATCC 13048 that are capable of withstanding high glycerol concentration as well as resisting ethanol-inhibition. The mutant will be used for high ethanol fermentation from glycerol feedstock. Ethanol production from pure (P-) and recovered (R-) glycerol using the stock was evaluated. A six-tube-subculture-generations method was used for developing the mutant. This involved subculturing the organism six consecutive times in tubes containing the same glycerol and ethanol concentrations at the same culture conditions. Then, the glycerol and/or ethanol concentration was increased and the six subculture generations were repeated. A strain capable of growing in 200 g/L glycerol and 30 g/L ethanol was obtained. The ability of this mutant, vis-à-vis the original strain, in utilizing glycerol in a high glycerol containing medium, with the concomitant ethanol yield, was assessed. Tryptic soy broth without dextrose (TSB) was used as the fermentation medium. Fermentation products were analyzed using HPLC. In a 20 g/L glycerol TSB, E. aerogenes ATCC 13048 converted 18.5 g/L P-glycerol and 17.8 g/L R-glycerol into 12 and 12.8 g/L ethanol, respectively. In a 50 g/L P-glycerol TSB, it utilized only 15.6 g/L glycerol; but the new strain used up 39 g/L, yielding 20 g/L ethanol after 120 h, an equivalence of 1.02 mol ethanol/mol-glycerol. This is the highest ethanol yield reported from glycerol bioconversion. The result of this P-glycerol fermentation can be duplicated using the R-glycerol from biodiesel production. PMID:22455837

  14. Biorefinery for Glycerol Rich Biodiesel Industry Waste.

    PubMed

    Kalia, Vipin Chandra; Prakash, Jyotsana; Koul, Shikha

    2016-06-01

    The biodiesel industry has the potential to meet the fuel requirements in the future. A few inherent lacunae of this bioprocess are the effluent, which is 10 % of the actual product, and the fact that it is 85 % glycerol along with a few impurities. Biological treatments of wastes have been known as a dependable and economical direction of overseeing them and bring some value added products as well. A novel eco-biotechnological strategy employs metabolically diverse bacteria, which ensures higher reproducibility and economics. In this article, we have opined, which organisms and what bioproducts should be the focus, while exploiting glycerol as feed. PMID:27570302

  15. Tandem transformation of glycerol to esters.

    PubMed

    Sotenko, Maria V; Rebroš, Martin; Sans, Victor S; Loponov, Konstantin N; Davidson, Matthew G; Stephens, Gill; Lapkin, Alexei A

    2012-12-31

    Tandem transformation of glycerol via microbial fermentation and enzymatic esterification is presented. The reaction can be performed with purified waste glycerol from biodiesel production in a continuous mode, combining continuous fermentation with membrane-supported enzymatic esterification. Continuous anaerobic fermentation was optimized resulting in the productivity of 2.4 g L⁻¹ h⁻¹ of 1,3-propanediol. Biphasic esterification of 1,3-propanediol was optimized to achieve ester yield of up to 75%. A hollow fibre membrane contactor with immobilized Rhizomucor miehei lipase was demonstrated for the continuous tandem fermentation-esterification process. PMID:22796408

  16. Effects of intravenous infusion of glycerol on blood parameters and urinary glycerol concentrations.

    PubMed

    Okano, Masato; Nishitani, Yasunori; Dohi, Michiko; Kageyama, Shinji

    2016-05-01

    In sports, the oral intake and intravenous administration of glycerol as a potential masking agent have been prohibited. The effect of glycerol on blood parameters was investigated by comparing the intravenous administration of glycerol (20g/200mL) with that of an electrolyte (8g glucose/200mL) as a comparator (n=7, fixed-dose-rate i.v. infusion, 200mL in 1h). This study was also designed to evaluate whether the urinary concentrations reached the positivity threshold after the intravenous infusion of glycerol. Significant decreases of the haemoglobin (HGB, g/dL), haematocrit (HCT, %) and OFF-h Score (OFF-score) values were observed after the infusion of glycerol (P<0.05 at 1-6h). The differences in the HGB, HCT and OFF-score between pre- and post-administration were -0.49±0.23g/dL (2h), -1.54±0.73% (2h) and -3.89±3.66 (2h), respectively. Glycerol infusion significantly increased the plasma volume by 12.1% (1h), 6.3% (2h) and 5.7% (3h) compared with the initial values. The infusion of the comparator also increased the plasma volume by 9.6% (1h), 5.8% (2h) and 4.9% (3h) compared with the values before infusion. There were no significant differences in the change of the plasma volume between the intravenous infusions of glycerol and the glucose-based electrolyte (as the comparator) (P≥0.05). This finding might indicate that glycerol itself only exhibited limited effects on the expansion of plasma. After administration of glycerol, the urinary glycerol concentrations increased from 0.0013±0.0004mg/mL to 6.86±2.86mg/mL at 1h and 6.45±3.08mg/mL at 2h. The intravenous infusion of glycerol can most likely be detected using the current urine analysis; however, the dependence of the concentration of urinary glycerol on the urine volume should be considered. PMID:26986972

  17. Genetic construction of recombinant Pseudomonas chlororaphis for improved glycerol utilization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study is to improve by genetic engineering the glycerol metabolic capability of Pseudomonas chlororaphis which is capable of producing commercially valuable biodegradable poly(hydroxyalkanoate) (PHA) and biosurfactant rhamnolipids (RLs). In the study, glycerol uptake facilitat...

  18. Sorption behavior of mixtures of glycerol and starch.

    PubMed

    Enrione, Javier I; Hill, Sandra E; Mitchell, John R

    2007-04-18

    Glycerol is often added to starches to plasticize the product, but the presence of glycerol may also affect the water content of the samples. To evaluate the effect of glycerol on the sorption properties of starches, waxy maize, rice, and wheat starch were thermomechanically extruded in the presence of glycerol. Sorption isotherms of these extruded samples were ascertained using dynamic vapor sorption (DVS). BET and GAB modeling showed a monolayer (mo) significantly higher for waxy maize than for rice and wheat. Glycerol inclusion changed the model values, indicating reduction in sorption energy at the monolayer and restructuring of the multilayer. An interaction factor (xi) based on weight fraction models was calculated. Differences in xi were obtained when glycerol was added, varying from approximately 0.9 for 5% glycerol to approximately 0.8 for 20% glycerol, supporting the hypothesis of interactions between starch and this polyol. PMID:17362027

  19. Determining Atmospheric Pressure with a Eudiometer and Glycerol

    ERIC Educational Resources Information Center

    Brody, Jed; Rohald, Kate; Sutton, Atasha

    2010-01-01

    We consider a volume of air trapped over a glycerol column in a eudiometer. We demonstrate that there is an approximately linear relationship between the volume of trapped air and the height of the glycerol column. Simply by moving the eudiometer up and down, we cause the glycerol-column height and trapped-air volume to vary. The plot of volume…

  20. Digestable and Metabolizable Energy of Crude Glycerol in Growing Pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The apparent DE and ME value of crude glycerol for growing pigs was determined in a series of 5 experiments using crude glycerol (86.95% glycerol) from a biodiesel production facility with soybean oil used as the initial feedstock (AG Processing Inc., Sergeant Bluff, IA). Dietary treatments were 0, ...

  1. 21 CFR 172.735 - Glycerol ester of rosin.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Glycerol ester of rosin. 172.735 Section 172.735 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... CONSUMPTION Other Specific Usage Additives § 172.735 Glycerol ester of rosin. Glycerol ester of wood...

  2. 21 CFR 172.735 - Glycerol ester of rosin.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Glycerol ester of rosin. 172.735 Section 172.735 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... CONSUMPTION Other Specific Usage Additives § 172.735 Glycerol ester of rosin. Glycerol ester of wood...

  3. 1,2-Isopropylidene glycerol carbonate: preparation, characterization, and hydrolysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The utilization of excess glycerol supplies derived from the burgeoning biodiesel industry is of major importance to the oleochemical industry as the economic viability of the biodiesel and oleochemical industries are closely linked to glycerol prices. Carbonate compounds based on glycerol, such as...

  4. Conversion of glycerol to hydrogen rich gas.

    PubMed

    Tran, Nguyen H; Kannangara, G S Kamali

    2013-12-21

    Presently there is a glut of glycerol as the by-product of biofuel production and it will grow as production increases. The conundrum is how we can consume this material and convert it into a more useful product. One potential route is to reform glycerol to hydrogen rich gas including synthesis gas (CO + H2) and hydrogen. However, there is recent literature on various reforming techniques which may have a bearing on the efficiency of such a process. Hence in this review reforming of glycerol at room temperature (normally photo-catalytic), catalysis at moderate and high temperature and a non-catalytic pyrolysis process are presented. The high temperature processes allow the generation of synthesis gas with the hydrogen to carbon monoxide ratios being suitable for synthesis of dimethyl ether, methanol and for the Fischer-Tropsch process using established catalysts. Efficient conversion of synthesis gas to hydrogen involves additional catalysts that assist the water gas shift reaction, or involves in situ capture of carbon dioxide and hydrogen. Reforming at reduced temperatures including photo-reforming offers the opportunity of producing synthesis gas or hydrogen using single catalysts. Together, these processes will assist in overcoming the worldwide glut of glycerol, increasing the competitiveness of the biofuel production and reducing our dependency on the fossil based, hydrogen rich gas. PMID:24043264

  5. Anaerobic treatment of crude glycerol from biodiesel production.

    PubMed

    Nakazawa, M M; Silva Júnior, W R S; Kato, M T; Gavazza, S; Florencio, L

    2015-01-01

    In this study, we evaluated the use of an up-flow anaerobic sludge blanket (UASB) reactor to treat crude glycerol obtained from cottonseed biodiesel production. The laboratory-scale UASB reactor (7.0 L) was operated at ambient temperature of 26.5°C with chemical oxygen demand (COD) concentrations between 0.5 and 8.0 g/L. The volatile fatty acid contents, pH, inorganic salt contents and biogas production were monitored during a 280-day experimental period. Molecular biology techniques were used to assess the microbial diversity in the bioreactor. The reactor achieved COD removal efficiencies of up to 92% except during one phase when the efficiency decreased to 81%. Biogas production remained stable throughout the experimental period, when the fraction converted to methane reached values as high as 68%. The profile of the denaturing gradient gel electrophoresis (DGGE) bands suggested slight changes in the microbial community during reactor operation. The overall results indicated that the crude glycerol from biodiesel production can serve as a suitable substrate for anaerobic degradation with a stable reactor performance and biogas production as long as the applied organic loads are up to 8.06 kg COD/m3·d. PMID:26465309

  6. Biological valorization of pure and crude glycerol into 1,3-propanediol using a novel isolate Lactobacillus brevis N1E9.3.3.

    PubMed

    Vivek, Narisetty; Pandey, Ashok; Binod, Parameswaran

    2016-08-01

    The aim of the study was to evaluate a novel onsite enrichment approach to isolate a crude glycerol utilizing facultative anaerobic bacteria. An onsite enrichment in natural conditions resulted an isolate, Lactobacillus brevis N1E9.3.3, that can utilize glycerol and produce 1,3-propanediol with a yield of 0.89g1,3-PDO/gGlycerol and productivity of 0.78g1,3-PDO/l/h at pH-8.5 under anaerobic conditions. Batch fermentation experiments with glycerol-glucose co-fermentation strategy was carried out to evaluate the production of 1,3-propanediol and other byproducts. The effect of other carbon sources as co-substrate was also evaluated. At the optimized condition, 18.6g/l 1,3-propanediol was monitored when biodiesel industry generated crude glycerol and 2.5% glucose were used as the substrate. PMID:26920628

  7. Glycerol oxidation using gold-containing catalysts.

    PubMed

    Villa, Alberto; Dimitratos, Nikolaos; Chan-Thaw, Carine E; Hammond, Ceri; Prati, Laura; Hutchings, Graham J

    2015-05-19

    Glycerol is an important byproduct of biodiesel production, and it is produced in significant amounts by transesterification of triglycerides with methanol. Due to the highly functionalized nature of glycerol, it is an important biochemical that can be utilized as a platform chemical for the production of high-added-value products. At present, research groups in academia and industry are exploring potential direct processes for the synthesis of useful potential chemicals using catalytic processes. Over the last 10 years, there has been huge development of potential catalytic processes using glycerol as the platform chemical. One of the most common processes investigated so far is the catalytic oxidation of glycerol at mild conditions for the formation of valuable oxygenated compounds used in the chemical and pharmaceutical industry. The major challenges associated with the selective oxidation of glycerol are (i) the control of selectivity to the desired products, (ii) high activity and resistance to poisoning, and (iii) minimizing the usage of alkaline conditions. To address these challenges, the most common catalysts used for the oxidation of glycerol are based on supported metal nanoparticles. The first significant breakthrough was the successful utilization of supported gold nanoparticles for improving the selectivity to specific products, and the second was the utilization of supported bimetallic nanoparticles based on gold, palladium, and platinum for improving activity and controlling the selectivity to the desired products. Moreover, the utilization of base-free reaction conditions for the catalytic oxidation of glycerol has unlocked new pathways for the production of free-base products, which facilitates potential industrial application. The advantages of using gold-based catalysts are the improvement of the catalyst lifetime, stability, and reusability, which are key factors for potential commercialization. In this Account, we discuss the advantages of the

  8. Synthesis of glycerol carbonate from glycerol and urea with gold-based catalysts.

    PubMed

    Hammond, Ceri; Lopez-Sanchez, Jose A; Ab Rahim, Mohd Hasbi; Dimitratos, Nikolaos; Jenkins, Robert L; Carley, Albert F; He, Qian; Kiely, Christopher J; Knight, David W; Hutchings, Graham J

    2011-04-21

    The reaction of glycerol with urea to form glycerol carbonate is mostly reported in the patent literature and to date there have been very few fundamental studies of the reaction mechanism. Furthermore, most previous studies have involved homogeneous catalysts whereas the identification of heterogeneous catalysts for this reaction would be highly beneficial. This is a very attractive reaction that utilises two inexpensive and readily available raw materials in a chemical cycle that overall, results in the chemical fixation of CO(2). This reaction also provides a route to up-grade waste glycerol produced in large quantities during the production of biodiesel. Previous reports are largely based on the utilisation of high concentrations of metal sulfates or oxides, which suffer from low intrinsic activity and selectivity. We have identified heterogeneous catalysts based on gallium, zinc, and gold supported on a range of oxides and the zeolite ZSM-5, which facilitate this reaction. The addition of each component to ZSM-5 leads to an increase in the reaction yield towards glycerol carbonate, but supported gold catalysts display the highest activity. For gold-based catalysts, MgO is the support of choice. Catalysts have been characterised by XRD, TEM, STEM and XPS, and the reaction has been studied with time-on-line analysis of products via a combination of FT-IR spectroscopy, HPLC, (13)C NMR and GC-MS analysis to evaluate the reaction pathway. Our proposed mechanism suggests that glycerol carbonate forms via the cyclization of a 2,3-dihydroxypropyl carbamate and that a subsequent reaction of glycerol carbonate with urea yields the carbamate of glycerol carbonate. Stability and reactivity studies indicate that consecutive reactions of glycerol carbonate can limit the selectivity achieved and reaction conditions can be selected to avoid this. The effect of the catalyst in the proposed mechanism is discussed. PMID:21258674

  9. Anaerobic digestion of glycerol and co-digestion of glycerol and pig manure.

    PubMed

    Nuchdang, Sasikarn; Phalakornkule, Chantaraporn

    2012-06-30

    The potential of glycerol obtained from transesterification of waste cooking oil as a main carbon source for biogas production was investigated. The glycerol was highly contaminated with oils and fats and was pretreated with sulfuric acid. Using a carbon source of glucose as a control, we compared biogas production from the acid-treated glycerol in a synthetic medium and the acid-treated glycerol mixed with pig manure. The anaerobic digestion of acid-treated glycerol with supplement in a synthetic medium was found to be satisfactory at organic loading rates (OLR) between 1.3, 1.6 and 2.6 g chemical oxygen demand (COD) L(-1) d(-1). The maximum methane yield of 0.32 L at Standard temperature and pressure (STP) g(-1) COD removal was achieved at an OLR of 1.6 g COD L(-1) d(-1) and the methane content was 54% on an average. At a higher organic loading rate of 5.4 g COD L(-1) d(-1), the propionic acid to acetic acid ratio was higher than the critical threshold limit for metabolic imbalance. Anaerobic digestion of acid-treated glycerol with pig manure was also investigated at the COD ratio of 80:20 (glycerol:pig manure). The anaerobic digestion of acid-treated glycerol with pig manure was found to be satisfactory at organic loading rates between 1.3, 1.7, 2.9 and 5.0 g COD L(-1) d(-1) in terms of COD reduction (>80%) and methane content of (62% on an average). However, the biogas production rate was found to significantly decrease at the highest load. The maximum methane yield of 0.24 L STP g(-1) COD removal was achieved at an OLR of 1.3 g COD L(-1) d(-1). PMID:22417895

  10. Antioxidant behavior of 1-feruloyl-sn-glycerol and 1,3-diferuloyl-sn-glycerol in phospholipid liposomes 1

    Technology Transfer Automated Retrieval System (TEKTRAN)

    1-Feruloyl-sn-glycerol (FG) and 1,3-diferuloyl-sn-glycerol (DFG) are two natural plant compounds that may be useful in cosmeceutical, food, and skin care applications because of excellent antioxidant properties. FG and DFG enzymatically synthesized through esterification of glycerol and soybean oil...

  11. Yeast Fps1 glycerol facilitator functions as a homotetramer.

    PubMed

    Beese-Sims, Sara E; Lee, Jongmin; Levin, David E

    2011-12-01

    The Saccharomyces cerevisiae Fps1 glycerol channel is a member of the major intrinsic protein (MIP) family of plasma membrane channel proteins that functions in osmoregulatory pathways to transport glycerol passively out of the cell. The MIP family is subdivided into members that are selectively permeable to water (aquaporins) and those permeated by glycerol (aquaglyceroporins or glycerol facilitators). Although aquaporins function as homo-tetramers with each monomer possessing its own channel, previous studies have suggested that aquaglyceroporins may function as monomers. Here we provide both genetic and biochemical evidence that Fps1 functions as a homotetramer to regulate glycerol transport in yeast. PMID:22030956

  12. Ultrasound assisted enzyme catalyzed synthesis of glycerol carbonate from glycerol and dimethyl carbonate.

    PubMed

    Waghmare, Govind V; Vetal, Mangesh D; Rathod, Virendra K

    2015-01-01

    The present work illustrates the transesterification of glycerol to glycerol carbonate (GlyC) from dimethyl carbonate (DMC) using commercial immobilized lipase (Novozym 435) under ultrasonic irradiation. The experiments were performed in a batch reactor placed in an ultrasonic water bath using a sequence of experimental protocol to evaluate the effects of temperature, molar ratios of substrates, enzyme loading, duty cycle and ultrasound power on the conversion of glycerol to GlyC. It has been found that ultrasound-assisted lipase-catalyzed transesterification of glycerol would be a potential alternative to conventional alkali-catalyzed method, as high conversion (99.75%) was obtained at mild operating conditions: molar ratio of DMC to glycerol 3:1, catalyst amount of 13% (w/w), lower power input (100W), duty cycle 50% and temperature (60°C) in a relatively short reaction time (4h) using Novozym 435 as catalyst. Ultrasound reduces the reaction time up to 4h as compared to conventional stirring method (14h) catalyzed by Novozym 435. The repeated use of the catalyst under the optimum experimental condition resulted in decay in both enzyme activity and product conversion. PMID:25069889

  13. Biological Conversion of Glycerol to Ethanol by Enterobacter aerogenes

    NASA Astrophysics Data System (ADS)

    Nwachukwu, Raymond E. S.

    In a search to turn the economically and environmentally non-valuable "waste" streams of biodiesel production into a profitable byproduct, a mutant strain of Enterobacter aerogenes ATCC 13048 was developed by six-tube subculturing technique. This technique is based on the principle of adaptive evolution, and involved subculturing the bacterium in a tryptic soy broth without dextrose (TSB) containing specific glycerol and ethanol concentration for six consecutive times. Then, the six consecutive subculturing was repeated in a fresh TSB of higher glycerol and ethanol concentrations. A new mutant strain, E. aerogenes S012, which could withstand a combination of 200 g/l glycerol and 30 g/l ethanol concentrations, was developed. The wild and mutant strains were used for the fermentation of pure (P-) and recovered (R-) glycerol. Taguchi and full factorial methods of design of experiments were used to screen and optimize the important process factors that influence the microbial production of ethanol. A statistically sound regression model was used to establish the mathematical relationship between the process variables and ethanol production. Temperature of 38°C, agitation speed of 200 rpm, pH of 6.3-6.6, and microaerobic condition were the optimum process conditions. Different pretreatment methods to recover glycerol from the crude glycerol and the subsequent fermentation method showed that direct acidification using 85% H3PO4 was the best. The R-glycerol contained 51% pure glycerol and 21% methanol. The wild strain, E. aerogenes ATCC 13048, produced only 12 g/l and 12.8 g/l ethanol from 20 g/l P- and R-glycerol respectively, and could not utilize higher glycerol concentrations. The mutant, E. aerogenes S012, produced ethanol amount and yield of 43 g/l and 1.12 mol/mol-glycerol from P-glycerol, respectively within 96 h. It also produced ethanol amount and yield of 26.8 g/l and 1.07 mol/mol-glycerol, respectively, from R-glycerol within the same duration. In a

  14. Glycerol metabolism promotes biofilm formation by Pseudomonas aeruginosa.

    PubMed

    Scoffield, Jessica; Silo-Suh, Laura

    2016-08-01

    Pseudomonas aeruginosa causes persistent infections in the airways of cystic fibrosis (CF) patients. Airway sputum contains various host-derived nutrients that can be utilized by P. aeruginosa, including phosphotidylcholine, a major component of host cell membranes. Phosphotidylcholine can be degraded by P. aeruginosa to glycerol and fatty acids to increase the availability of glycerol in the CF lung. In this study, we explored the role that glycerol metabolism plays in biofilm formation by P. aeruginosa. We report that glycerol metabolism promotes biofilm formation by both a chronic CF isolate (FRD1) and a wound isolate (PAO1) of P. aeruginosa. Moreover, loss of the GlpR regulator, which represses the expression of genes involved in glycerol metabolism, enhances biofilm formation in FRD1 through the upregulation of Pel polysaccharide. Taken together, our results suggest that glycerol metabolism may be a key factor that contributes to P. aeruginosa persistence by promoting biofilm formation. PMID:27392247

  15. Measuring glycerol turnover, gluconeogenesis from glycerol, and total gluconeogenesis with [2-13C] glycerol: role of the infusion-sampling mode.

    PubMed

    Peroni, O; Large, V; Odeon, M; Beylot, M

    1996-07-01

    Mass isotopomer distribution analysis (MIDA) of glucose during infusion of [2-13C]glycerol is a new method for measuring total gluconeogenesis (GNG). Since this method relies on calculation of the isotopic enrichment (IE) of hepatic triose phosphates (TP), the results should be independent of the sites of tracer infusion and blood sampling. Postabsorptive and starved rats were infused with [2-13C]glycerol and sampled either in the arterial-venous (A-V) or venous-arterial (V-A) modes. Blood was also sampled from the portal vein. In both postabsorptive and starved rats, glycerol turnover rate (Rt) and the percent contribution of glycerol to total glucose production were higher in the A-V mode than in the V-A mode (P < .05). Glycerol IE in portal venous blood was intermediate between IE values observed in peripheral arterial and venous blood. Its use for calculating the contribution of glycerol to glucose production reconciled the results obtained with the two infusion-sampling modes in both postabsorptive and starved rats; this contribution was increased by starvation (P < .01). In postabsorptive rats, total GNG calculated from MIDA of glucose accounted for approximately 50% of glucose production whatever the infusion-sampling mode (A-V, 48.8% +/- 4.7%; V-A, 52.2% +/- 3.9%). This contribution increased to 90% in starved rats, again, with no difference between A-V (95.2% +/- 1.8%) and V-A (89.2% +/- 1.3%) modes. In conclusion, during infusion of [2-13C]glycerol, total GNG measured from MIDA of glucose is independent of the infusion-sampling mode, contrary to calculations of Rt and GNG from glycerol. Measurement of glycerol IE in portal venous blood reconciles the results obtained with the two modes with respect to the contribution of glycerol to GNG. PMID:8692028

  16. Monitors.

    ERIC Educational Resources Information Center

    Powell, David

    1984-01-01

    Provides guidelines for selecting a monitor to suit specific applications, explains the process by which graphics images are produced on a CRT monitor, and describes four types of flat-panel displays being used in the newest lap-sized portable computers. A comparison chart provides prices and specifications for over 80 monitors. (MBR)

  17. Criteria for Quick and Consistent Synthesis of Poly(glycerol sebacate) for Tailored Mechanical Properties.

    PubMed

    Li, Xinda; Hong, Albert T-L; Naskar, Nilanjon; Chung, Hyun-Joong

    2015-05-11

    Poly(glycerol sebacate) (PGS) and its derivatives make up an attractive class of biomaterial owing to their tunable mechanical properties with programmable biodegradability. In practice, however, the application of PGS is often hampered by frequent inconsistency in reproducing process conditions. The inconsistency stems from the volatile nature of glycerol during the esterification process. In this study, we suggest that the degree of esterification (DE) can be used to predict precisely the physical status, the mechanical properties, and the degradation of the PGS materials. Young's modulus is shown to linearly increase with DE, which is in agreement with an entropic spring theory of rubbers. To provide a processing guideline for researchers, we also provide a physical status map as a function of curing temperature and time. The amount of glycerol loss, obtainable by monitoring the evolution of the total mass loss and the DE during synthesis, is shown to make the predictions even more precise. We expect that these strategies can be applicable to different categories of polymers that involve condensation polymerization with the volatility of the reactants. In addition, we demonstrate that microwave-assisted prepolymerization is a time- and energy-efficient pathway to obtain PGS. For example, 15 min of microwave time is shown to be as efficient as prepolymerization in nitrogen atmosphere for 6 h at 130 °C. The quick synthesis method, however, causes a severe evaporation of glycerol, resulting in a large distortion in the monomer ratio between glycerol and sebacic acid. Consequently, more rigid PGS is produced under a similar curing condition compared to the conventional prepolymerization method. Finally, we demonstrate that the addition of molecularly rigid cross-linking agents and network-structured inorganic nanoparticles are also effective in enhancing the mechanical properties of the PGS-derived materials. PMID:25857651

  18. Fermentation of xylose to glycerol by Rhizopus javanicus

    SciTech Connect

    Lu, Z.; Yang, C.W.; Tsao, G.T.

    1995-12-31

    Glycerol production from xylose fermentation using Rhizopus javanicus (ATCC 22581) has been investigated in shake flasks. The medium composition (xylose concentration, nitrogen sources), aeration rate, and temperature have been found to affect the accumulation and yield of glycerol. Some of these effects are explained in terms of the critical parameters, osmotic pressure, and dissolved oxygen levels in the medium. Relatively high glycerol yields and concentrations have been obtained at high sugar concentration with high level of aeration at room temperature. The addition of polyethylene glycol or sulfite can improve the yield and accumulation of glycerol.

  19. Electrical dual-sensing method for real-time quantitative monitoring of cell-secreted MMP-9 and cellular morphology during migration process.

    PubMed

    Tran, Trong Binh; Nguyen, Phuong Diem; Baek, Changyoon; Min, Junhong

    2016-03-15

    MMP-9 (92 kDa gelatinease), which is member of matrix metalloproteinases (MMPs) family, plays a crucial role in the breakdown of extracellular matrix (ECM) by degrading the major components of ECM that lead to tumor cell invasion and metastasis through the basement membrane. Our study presents the on-chip dual-sensing device for rapid detection of cell-secreted MMP-9 and corresponding cell morphology changes in real-time domain. The device consists of 2 sensing platforms (both are interdigitated array microelectrodes - IDAMs) within 1 common fluidic chamber: one detects the cell morphology responses via Electric Cell-substrate Impedance Sensing (ECIS) technique, meanwhile the other records the cleavage effect between cell-secreted MMP-9 and the surface immobilized peptide via the capacitance-based sensing method. Thanks to the selectivity of designed peptide, this approach allows the rapid and specific detection of MMP-9. In comparison with gold standard ELISA assay, the detection time was significantly reduced from over 4h to within 30 min with the wide detection range from 10 pM to 10nM. Finally, this study provides the novel model for MMP-9 protease direct detection from living cell and new insights in multi-purpose detection of cancer associated enzyme and cell migration behavior. PMID:26485177

  20. A double blind, randomised controlled trial of glycerol adjuvant therapy in adult bacterial meningitis in a high HIV seroprevalence setting in Malawi

    PubMed Central

    Ajdukiewicz, Katherine M.B.; Cartwright, Katharine E.; Scarborough, Matthew; Mwambene, James B.; Goodson, Patrick; Molyneux, Malcolm E.; Zijlstra, Eduard E.; French, Neil; Whitty, Christopher J.M.; Lalloo, David G.

    2014-01-01

    Summary Background Southern Africa has a high incidence of bacterial meningitis in adults, often associated with HIV co-infection. Even with appropriate antibiotic therapy, mortality exceeds 50% and is not improved with corticosteroids. Glycerol adjuvant therapy reduced mortality and long-term morbidity (deafness) in bacterial meningitis in children and is being promoted. If similarly effective in adults, glycerol would provide a cheap, available adjuvant therapy in Africa. Methods Following a dose-finding study, we conducted a randomised double-blind placebo-controlled trial of oral glycerol in adults with bacterial meningitis. Patients with clinical and CSF findings suggestive of bacterial meningitis were randomised either to glycerol or an equivalent volume of sugar solution. The primary outcome was mortality at 40 days with secondary outcomes including disability and mortality restricted to pneumococcal disease. Findings 75ml glycerol QDS was best tolerated and was used for the main study. 265 patients were randomised to receive glycerol or placebo. The trial was stopped early on the advice of the Data and Safety Monitoring Board (DSMB) following a planned interim analysis. Mortality by day 40 was 61/125 (49%) in the placebo and 86/136 (69%) in the glycerol arms, Adjusted Odds Ratio 2·4 (95% CI 1·3-4·2 p0·003). There was no benefit from glycerol for death and disability by day 40 by intention to treat or in predefined subgroups. Two serious adverse events occurred possibly due to study drug. Interpretation Oral glycerol therapy did not improve mortality in adults with bacterial meningitis and cannot be recommended as a suitable adjuvant therapy in resource-poor settings with a high HIV prevalence. PMID:21334262

  1. Ruminal fermentation of propylene glycol and glycerol.

    PubMed

    Trabue, Steven; Scoggin, Kenwood; Tjandrakusuma, Siska; Rasmussen, Mark A; Reilly, Peter J

    2007-08-22

    Bovine rumen fluid was fermented anaerobically with 25 mM R-propylene glycol, S-propylene glycol, or glycerol added. After 24 h, all of the propylene glycol enantiomers and approximately 80% of the glycerol were metabolized. Acetate, propionate, butyrate, valerate, and caproate concentrations, in decreasing order, all increased with incubation time. Addition of any of the three substrates somewhat decreased acetate formation, while addition of either propylene glycol increased propionate formation but decreased that of butyrate. R- and S-propylene glycol did not differ significantly in either their rates of disappearance or the products formed when they were added to the fermentation medium. Fermentations of rumen fluid containing propylene glycol emitted the sulfur-containing gases 1-propanethiol, 1-(methylthio)propane, methylthiirane, 2,4-dimethylthiophene, 1-(methylthio)-1-propanethiol, dipropyl disulfide, 1-(propylthio)-1-propanethiol, dipropyl trisulfide, 3,5-diethyl-1,2,4-trithiolane, 2-ethyl-1,3-dithiane, and 2,4,6-triethyl-1,3,5-trithiane. Metabolic pathways that yield each of these gases are proposed. The sulfur-containing gases produced during propylene glycol fermentation in the rumen may contribute to the toxic effects seen in cattle when high doses are administered for therapeutic purposes. PMID:17655323

  2. Functional characterization of Yersinia pestis aerobic glycerol metabolism.

    PubMed

    Willias, Stephan P; Chauhan, Sadhana; Motin, Vladimir L

    2014-11-01

    Yersinia pestis biovar Orientalis isolates have lost the capacity to ferment glycerol. Herein we provide experimental validation that a 93 bp in-frame deletion within the glpD gene encoding the glycerol-3-phosphate dehydrogenase present in all biovar Orientalis strains is sufficient to disrupt aerobic glycerol fermentation. Furthermore, the inability to ferment glycerol is often insured by a variety of additional mutations within the glpFKX operon which prevents glycerol internalization and conversion to glycerol-3-phosphate. The physiological impact of functional glpFKX in the presence of dysfunctional glpD was assessed. Results demonstrate no change in growth kinetics at 26 °C and 37 °C. Mutants deficient in glpD displayed decreased intracellular accumulation of glycerol-3-phosphate, a characterized inhibitor of cAMP receptor protein (CRP) activation. Since CRP is rigorously involved in global regulation Y. pestis virulence, we tested a possible influence of a single glpD mutation on virulence. Nonetheless, subcutaneous and intranasal murine challenge was not impacted by glycerol metabolism. As quantified by crystal violet assay, biofilm formation of the glpD-deficient KIM6+ mutant was mildly repressed; whereas, chromosomal restoration of glpD in CO92 resulted in a significant increase in biofilm formation. PMID:25220241

  3. Synthesis and applications of {sup 13}C glycerol

    SciTech Connect

    Stocking, E.; Khalsa, O.; Martinez, R.A.; Silks, L.A. III

    1994-12-01

    Due in part to the use of labeled glycerol for the {sup 13}C enrichment of biomolecules, we are currently developing new synthetic routes to various isotopomers of glycerol. Judging from our experience, traditional methods of glycerol synthesis are not easily adapted for isotopic enrichment and/or have poor overall yields (12 to 15%). Furthermore, the use of glycerol for enrichment can be prohibitively expensive and its availability is limited by the level of demand. We are presently developing a short de novo synthesis of glycerol from carbon dioxide ({approximately}53% overall yield for four steps) and are examining the feasibility of synthesizing site-specific {sup 13}C-labeled glycerol and dihydroxyacetone (DHA) from labeled methanol and carbon dioxide. One application of {sup 13}C glycerol we have examined is enzymatic conversion of glycerol to glyceraldehyde-3-monophosphate or dihydroxyacetone monophosphate (DHAP) with yields ranging from 25 to 50% (as determined by NMR spectroscopy). We are also pursuing the chemical conversion of {sup 13}C-labeled DHA to DHAP. We are especially interested in {sup 13}C-labeled DHAP because we are investigating its use as a chemo-enzymatic precursor for both labeled 2-deoxyribose and 2-deoxyribonucleic acids.

  4. Degradation rates of glycerol polyesters at acidic and basic conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Polyesters prepared from glycerol with mixtures of adipic and citric acids were evaluated in the laboratory to estimate degradation rates over a range of pH conditions. These renewable polymers provide a market for glycerol that is generated during biodiesel production. The polyesters were prepared...

  5. The Acrylation of Glycerol: a Precursor to Functionalized Lipids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Didecanoylacryloylglycerol was synthesized from decanoic and acrylic acids and glycerol using K2O as catalyst. This reaction was carried out in hexane in a closed stainless steel reactor at 200°C for 5h. The reactants were added in a 1:3:4 glycerol:decanoic acid:acrylic acid molar ratio. The resu...

  6. Biodegradation of Glycerol Trinitrate and Pentaerythritol Tetranitrate by Agrobacterium radiobacter

    PubMed Central

    White, G. F.; Snape, J. R.; Nicklin, S.

    1996-01-01

    Bacteria capable of metabolizing highly explosive and vasodilatory glycerol trinitrate (GTN) were isolated under aerobic and nitrogen-limiting conditions from soil, river water, and activated sewage sludge. One of these strains (from sewage sludge) chosen for further study was identified as Agrobacterium radiobacter subgroup B. A combination of high-pressure liquid chromatography and nuclear magnetic resonance analyses of the culture medium during the growth of A. radiobacter on basal salts-glycerol-GTN medium showed the sequential conversion of GTN to glycerol dinitrates and glycerol mononitrates. Isomeric glycerol 1,2-dinitrate and glycerol 1,3-dinitrate were produced simultaneously and concomitantly with the disappearance of GTN, with significant regioselectivity for the production of the 1,3-dinitrate. Dinitrates were further degraded to glycerol 1- and 2-mononitrates, but mononitrates were not biodegraded. Cells were also capable of metabolizing pentaerythritol tetranitrate, probably to its trinitrate and dinitrate analogs. Extracts of broth-grown cells contained an enzyme which in the presence of added NADH converted GTN stoichiometrically to nitrite and the mixture of glycerol dinitrates. The specific activity of this enzyme was increased 160-fold by growth on GTN as the sole source of nitrogen. PMID:16535244

  7. Fabrication of a glycerol from CO2 reaction system, supplement

    NASA Technical Reports Server (NTRS)

    Weiss, A. H.

    1973-01-01

    The fabrication, installation, and testing of a glycerol hydrogenation and a CO2 hydrogenation - CH4 partial oxidation units are reported. The glycerol system proved to be operational while the CO2 system was installed but not bought on operational steam.

  8. Transketolase activity modulates glycerol-3-phosphate levels in Escherichia coli.

    PubMed

    Vimala, A; Harinarayanan, R

    2016-04-01

    Transketolase activity provides an important link between the metabolic pathways of glycolysis and pentose phosphate shunt and catalyzes inter-conversions between pentose phosphates and glycolytic intermediates. It is widely conserved in life forms. A genetic screen for suppression of the growth defect of Escherichia coli tktA tktB mutant in LB medium revealed two mutations, one that rendered the glpK expression constitutive and another that inactivated deoB. Characterizing these mutations aided in uncovering the role of ribose-5-P (a transketolase substrate) as an inhibitor of glycerol assimilation and de novo glycerol-3-P synthesis. Using lacZ fusions, we show that ribose-5-P enhances GlpR-mediated repression of the glpFKX operon and inhibits glycerol assimilation. Electrophoretic Mobility Shift Assay (EMSA) showed ribose-5-P made the DNA-GlpR complex less sensitive to the inducer glycerol-3-P. In addition to inhibition of glycerol assimilation, obstruction of ribose-5-P metabolism retards growth from glycerol-3-P limitation. Glucose helps to overcome this limitation through a mechanism involving catabolite repression. To our knowledge, this report is the first to show ribose-5-P can modulate glycerol-3-P concentration in the cell by regulation of glycerol assimilation as well as its de novo synthesis. This regulation could be prevalent in other organisms. PMID:26691989

  9. THERMOPLASTIC STARCH-KRAFT LIGNIN-GLYCEROL BLENDS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Starch-kraft lignin-glycerol blends were extruded in a twin-screw extruder to produce non-brittle films. One week after extrusion, films with a mid-range composition of 52% starch, 20% lignin, and 28% glycerol showed a tensile strength at break of 2.8 MPa, Young's modulus of 48 MPa, and elongation ...

  10. PREPARATION AND CHARACTERIZATION OF 4-METHOXY CINNAMOYL GLYCEROL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glycerol was combined with cinnamic acid to prepare the corresponding ester, glycerol cinnamate. Conversions of 81% were achieved after 16 hr in toluene at reflux conditions. The product was recovered by extraction with distilled water and diethyl ether. The isolated product displayed strong abso...

  11. Glycerol, an underestimated flavor precursor in the Maillard reaction.

    PubMed

    Smarrito-Menozzi, Candice; Matthey-Doret, Walter; Devaud-Goumoens, Stéphanie; Viton, Florian

    2013-10-30

    The objective of the present work was to investigate in depth the role of glycerol in Maillard reactions and its potential to act as an active flavor precursor. Reactions using isotopically labeled compounds (various reducing sugars, proline, and glycerol) unambiguously demonstrated that, in addition to its role of solvent, glycerol actively contributes to the formation of proline-specific compounds in Maillard model systems. Additionally, rhamnose and fucose/proline/glycerol systems generated the 2-propionyl-1(3),4,5,6-tetrahydropyridines, known for their roasty, popcorn aroma. Their formation from such systems is unprecedented. The results presented here have direct implications for flavor generation during thermal processing of foods containing glycerol, which is a ubiquitous food ingredient and an underestimated flavor precursor. PMID:23373461

  12. Microbial conversion of glycerol to 1,3-propanediol

    SciTech Connect

    Zeng, A.P.; Biebl, H.; Deckwer, W.D.

    1996-10-01

    Glycerol is a byproduct from the soap and detergent industry and possibly from future biodiesel plants. The conversion of glycerol to 1,3-propanediol (PD) is of industrial interest due to the potential use of PD for the synthesis of polyesters. We have been studying the microbial conversion of glycerol to PD with work ranging from strain isolation, medium optimization, pathway analysis, product formation kinetics and growth modeling, downstream processing and reactor scale-up (up to 2000 1). PD yields of nearly 100% of the theoretical maximum (0.72 mol/mol glycerol) and final product concentrations of about 65 g/l were achieved with both Klebsiella pneumoniae and Clostridium butyricum. In addition to summarizing our experimental results the advances of bioconversion of glycerol will be reviewed in this presentation, with emphasis on discussing further research and development needs in this area. Results of process engineering and cost analysis will also be presented.

  13. Toxic and osmotic effects of glycerol on human granulocytes

    SciTech Connect

    Armitage, W.J.; Mazur, P.

    1984-11-01

    Human granulocytes are damaged by exposure to concentrations of glycerol as low as 0.5 M. We therefore investigated the addition of glycerol to granulocytes and its subsequent dilution under various conditions to try to distinguish between toxic and harmful osmotic effects of glycerol. The lesion caused by glycerol at 0/sup 0/C was expressed as a loss of plasma membrane integrity (as visualized by fluorescein diacetate) only after incubation (greater than or equal to1 h) at 37/sup 0/C. This damage was not ameliorated when osmotic stress was lessened by reducing the rates of addition and dilution of glycerol to keep the computed cell volume within 80-170% of isotonic cell volume. However, when osmotic stress was reduced further by increasing the temperature of addition and dilution of glycerol from 0/sup 0/ to 22/sup 0/C, the tolerance of the cells to 1 M glycerol increased somewhat. Reducing exposure to glycerol to 3 min or less at 0/sup 0/C greatly increased survival, but this time was too short to allow glycerol to equilibrate intracellularly. Finally, the presence of extra impermeant solute (NaCl or sucrose) in the medium to reduce the equilibrium cell volume to 60% of isotonic cell volume enabled granulocytes to survive 30-min exposure to 1 M glycerol at 0/sup 0/C, but cells had to remain shrunken during the 37/sup 0/C incubation to prevent the loss of membrane integrity. Suspensions that contained damaged granulocytes formed aggregates when incubated at 37/sup 0/C, and these aggregates were responsible for a major fraction of the observed loss in viability.

  14. Feruloyl glycerol and 1,3-diferuloyl glycerol antioxidant behavior in phospholipid vesicles.

    PubMed

    Evans, Kervin O; Compton, David L; Laszlo, Joseph A; Appell, Michael

    2016-02-01

    Feruloyl-sn-glycerol (FG) and 1,3-diferuloyl-sn-glycerol (F2G), the by-product of biocatalytic transesterification soybean oil and ethyl ferulate, were examined for their behavior in phospholipid vesicles. Based on absorbance and fluorescence methods, FG and F2G both were found to partition into vesicles and incorporate well into 1,2-dioleoylphosphocholine (DOPC) vesicles. FG and F2G incorporation resulted in vesicles that were as or slightly more stable than the unloaded vesicles. FG and F2G both demonstrated the ability to maintain antioxidant properties within the lipid bilayer. Bilayer depth analysis was conducted using the parallax method and molecular modeling. PMID:26561732

  15. Renewable chemicals: dehydroxylation of glycerol and polyols.

    PubMed

    ten Dam, Jeroen; Hanefeld, Ulf

    2011-08-22

    The production of renewable chemicals is gaining attention over the past few years. The natural resources from which they can be derived in a sustainable way are most abundant in sugars, cellulose and hemicellulose. These highly functionalized molecules need to be de-functionalized in order to be feedstocks for the chemical industry. A fundamentally different approach to chemistry thus becomes necessary, since the traditionally employed oil-based chemicals normally lack functionality. This new chemical toolbox needs to be designed to guarantee the demands of future generations at a reasonable price. The surplus of functionality in sugars and glycerol consists of alcohol groups. To yield suitable renewable chemicals these natural products need to be defunctionalized by means of dehydroxylation. Here we review the possible approaches and evaluate them from a fundamental chemical aspect. PMID:21887771

  16. Renewable Chemicals: Dehydroxylation of Glycerol and Polyols

    PubMed Central

    ten Dam, Jeroen; Hanefeld, Ulf

    2011-01-01

    The production of renewable chemicals is gaining attention over the past few years. The natural resources from which they can be derived in a sustainable way are most abundant in sugars, cellulose and hemicellulose. These highly functionalized molecules need to be de-functionalized in order to be feedstocks for the chemical industry. A fundamentally different approach to chemistry thus becomes necessary, since the traditionally employed oil-based chemicals normally lack functionality. This new chemical toolbox needs to be designed to guarantee the demands of future generations at a reasonable price. The surplus of functionality in sugars and glycerol consists of alcohol groups. To yield suitable renewable chemicals these natural products need to be defunctionalized by means of dehydroxylation. Here we review the possible approaches and evaluate them from a fundamental chemical aspect. PMID:21887771

  17. Functional Genomics Via Metabolic Footprinting: Monitoring Metabolite Secretion by Escherichia Coli Tryptophan Metabolism Mutants Using FT–IR and Direct Injection Electrospray Mass Spectrometry

    PubMed Central

    Kaderbhai, Naheed N.; Broadhurst, David I.; Ellis, David I.; Goodacre, Royston

    2003-01-01

    We sought to test the hypothesis that mutant bacterial strains could be discriminated from each other on the basis of the metabolites they secrete into the medium (their ‘metabolic footprint’), using two methods of ‘global’ metabolite analysis (FT–IR and direct injection electrospray mass spectrometry). The biological system used was based on a published study of Escherichia coli tryptophan mutants that had been analysed and discriminated by Yanofsky and colleagues using transcriptome analysis. Wild-type strains supplemented with tryptophan or analogues could be discriminated from controls using FT–IR of 24 h broths, as could each of the mutant strains in both minimal and supplemented media. Direct injection electrospray mass spectrometry with unit mass resolution could also be used to discriminate the strains from each other, and had the advantage that the discrimination required the use of just two or three masses in each case. These were determined via a genetic algorithm. Both methods are rapid, reagentless, reproducible and cheap, and might beneficially be extended to the analysis of gene knockout libraries. PMID:18629082

  18. Design and analysis of biorefineries based on raw glycerol: addressing the glycerol problem.

    PubMed

    Posada, John A; Rincón, Luis E; Cardona, Carlos A

    2012-05-01

    Glycerol as a low-cost by-product of the biodiesel industry can be considered a renewable building block for biorefineries. In this work, the conversion of raw glycerol to nine added-value products obtained by chemical (syn-gas, acrolein, and 1,2-propanediol) or bio-chemical (ethanol, 1,3-propanediol, d-lactic acid, succinic acid, propionic acid, and poly-3-hydroxybutyrate) routes were considered. The technological schemes for these synthesis routes were designed, simulated, and economically assessed using Aspen Plus and Aspen Icarus Process Evaluator, respectively. The techno-economic potential of a glycerol-based biorefinery system for the production of fuels, chemicals, and plastics was analyzed using the commercial Commercial Sale Price/Production Cost ratio criteria, under different production scenarios. More income can be earned from 1,3-propanediol and 1,2-propanediol production, while less income would be obtained from hydrogen and succinic acid. This analysis may be useful mainly for biodiesel producers since several profitable alternatives are presented and discussed. PMID:22349197

  19. Glycerol dynamics in weight-losing cancer patients.

    PubMed

    Edén, E; Edström, S; Bennegárd, K; Lindmark, L; Lundholm, K

    1985-02-01

    This study was designed to show whether weight-losing cancer patients have an elevated glycerol turnover. Four groups of patients were examined: weight-losing cancer patients, weight-losing patients without cancer, cancer patients without weight loss, and weight-stable and well-nourished hospitalized control patients. Glycerol was infused intravenously at three different rates (200, 400, and 800 mumol/hr/kg body weight) after an overnight fast. This allowed measurement of clearance and plasma glycerol turnover. Weight-losing cancer patients (group 1) had an almost threefold higher glycerol turnover per kilogram of body weight compared with malnourished and well-nourished noncancer patients. However, both malnourished cancer and noncancer patients had an elevated glycerol turnover compared with well-nourished patients when glycerol turnover was related to whole body lipids. The results how that progressive clinical cancer is associated with an elevated plasma glycerol turnover, probably indicating an increased whole body lipolysis. This may explain the loss of body fat during the development of cancer cachexia. PMID:4038560

  20. Structural Determination and Toll-like Receptor 2-dependent Proinflammatory Activity of Dimycolyl-diarabino-glycerol from Mycobacterium marinum*

    PubMed Central

    Elass-Rochard, Elisabeth; Rombouts, Yoann; Coddeville, Bernadette; Maes, Emmanuel; Blervaque, Renaud; Hot, David; Kremer, Laurent; Guérardel, Yann

    2012-01-01

    Although it was identified in the cell wall of several pathogenic mycobacteria, the biological properties of dimycolyl-diarabino-glycerol have not been documented yet. In this study an apolar glycolipid, presumably corresponding to dimycolyl-diarabino-glycerol, was purified from Mycobacterium marinum and subsequently identified as a 5-O-mycolyl-β-Araf-(1→2)-5-O-mycolyl-α-Araf-(1→1′)-glycerol (designated Mma_DMAG) using a combination of nuclear magnetic resonance spectroscopy and mass spectrometry analyses. Lipid composition analysis revealed that mycolic acids were dominated by oxygenated mycolates over α-mycolates and devoid of trans-cyclopropane functions. Highly purified Mma_DMAG was used to demonstrate its immunomodulatory activity. Mma_DMAG was found to induce the secretion of proinflammatory cytokines (TNF-α, IL-8, IL-1β) in human macrophage THP-1 cells and to trigger the expression of ICAM-1 and CD40 cell surface antigens. This activation mechanism was dependent on TLR2, but not on TLR4, as demonstrated by (i) the use of neutralizing anti-TLR2 and -TLR4 antibodies and by (ii) the detection of secreted alkaline phosphatase in HEK293 cells co-transfected with the human TLR2 and secreted embryonic alkaline phosphatase reporter genes. In addition, transcriptomic analyses indicated that various genes encoding proinflammatory factors were up-regulated after exposure of THP-1 cells to Mma_DMAG. Importantly, a wealth of other regulated genes related to immune and inflammatory responses, including chemokines/cytokines and their respective receptors, adhesion molecules, and metalloproteinases, were found to be modulated by Mma_DMAG. Overall, this study suggests that DMAG may be an active cell wall glycoconjugate driving host-pathogen interactions and participating in the immunopathogenesis of mycobacterial infections. PMID:22798072

  1. Monitoring

    DOEpatents

    Orr, Christopher Henry; Luff, Craig Janson; Dockray, Thomas; Macarthur, Duncan Whittemore

    2004-11-23

    The invention provides apparatus and methods which facilitate movement of an instrument relative to an item or location being monitored and/or the item or location relative to the instrument, whilst successfully excluding extraneous ions from the detection location. Thus, ions generated by emissions from the item or location can successfully be monitored during movement. The technique employs sealing to exclude such ions, for instance, through an electro-field which attracts and discharges the ions prior to their entering the detecting location and/or using a magnetic field configured to repel the ions away from the detecting location.

  2. Direct effect of incretin hormones on glucose and glycerol metabolism and hemodynamics.

    PubMed

    Karstoft, Kristian; Mortensen, Stefan P; Knudsen, Sine H; Solomon, Thomas P J

    2015-03-01

    The objective of this study was to assess the insulin-independent effects of incretin hormones on glucose and glycerol metabolism and hemodynamics under euglycemic and hyperglycemic conditions. Young, healthy men (n=10) underwent three trials in a randomized, controlled, crossover study. Each trial consisted of a two-stage (euglycemia and hyperglycemia) pancreatic clamp (using somatostatin to prevent endogenous insulin secretion). Glucose and lipid metabolism was measured via infusion of stable glucose and glycerol isotopic tracers. Hemodynamic variables (femoral, brachial, and common carotid artery blood flow and flow-mediated dilation of the brachial artery) were also measured. The three trials differed as follows: 1) saline [control (CON)], 2) glucagon-like peptide (GLP-1, 0.5 pmol·kg(-1)·min(-1)), and 3) glucose-dependent insulinotropic polypeptide (GIP, 1.5 pmol·kg(-1)·min(-1)). No between-trial differences in glucose infusion rates (GIR) or glucose or glycerol kinetics were seen during euglycemia, whereas hyperglycemia resulted in increased GIR and glucose rate of disappearance during GLP-1 compared with CON and GIP (P<0.01 for all). However, when normalized to insulin levels, no differences between trials were seen for GIR or glucose rate of disappearance. Besides a higher femoral blood flow during hyperglycemia with GIP (vs. CON and GLP-1, P<0.001), no between-trial differences were seen for the hemodynamic variables. In conclusion, GLP-1 and GIP have no direct effect on whole body glucose metabolism or hemodynamics during euglycemia. On the contrary, during hyperglycemia, GIP increases femoral artery blood flow with no effect on glucose metabolism, whereas GLP-1 increases glucose disposal, potentially due to increased insulin levels. PMID:25564476

  3. Glycerol uptake is by passive diffusion in the heart but by facilitated transport in RBCs at high glycerol levels in cold acclimated rainbow smelt (Osmerus mordax).

    PubMed

    Clow, Kathy A; Driedzic, William R

    2012-04-15

    Rainbow smelt (Osmerus mordax) is a small fish that accumulates glycerol at low winter seawater temperatures. In laboratory-held fish, glycerol concentration typically reaches 225 mM in plasma and in all cells. Glycerol uptake by the heart and red blood cells (RBCs) was assessed by tracking [(14)C(U)]glycerol into the acid-soluble pool. In fish acclimated to 9-10°C a decrease in perfusion/incubation temperature from 8 to 1°C resulted in a decrease in glycerol uptake with a Q(10) of 3.2 in heart and 2.4 in RBCs. Acclimation to ∼1.5°C did not result in an adaptive enhancement of glycerol uptake as rates were unchanged in heart and RBCs. Glycerol uptake at 1°C was by passive diffusion in heart as evidenced by a linear relationship between glycerol uptake and extracellular glycerol concentration and a lack of inhibition by phloretin. In contrast, in RBCs, glycerol uptake with respect to glycerol concentration showed two linear relationships with a transition point around 50 mM extracellular glycerol. The slope of the second phase was much steeper and eliminated with the inclusion of phloretin. In RBCs from Atlantic salmon (Salmo salar), a related species that does not accumulate glycerol, glycerol uptake showed only a single linear curve and was not inhibited by phloretin. The data imply a strong facilitated component to glycerol uptake in rainbow smelt RBCs at high glycerol concentrations. We propose this is related to cyclic changes in RBC glycerol content involving a loss of glycerol at the gill and a reaccumulation during passage through the liver. PMID:22319051

  4. Production of polyhydroxybutyrate and alginate from glycerol by Azotobacter vinelandii under nitrogen-free conditions

    PubMed Central

    Yoneyama, Fuminori; Yamamoto, Mayumi; Hashimoto, Wataru; Murata, Kousaku

    2015-01-01

    Glycerol is an interesting feedstock for biomaterials such as biofuels and bioplastics because of its abundance as a by-product during biodiesel production. Here we demonstrate glycerol metabolism in the nitrogen-fixing species Azotobacter vinelandii through metabolomics and nitrogen-free bacterial production of biopolymers, such as poly-d-3-hydroxybutyrate (PHB) and alginate, from glycerol. Glycerol-3-phosphate was accumulated in A. vinelandii cells grown on glycerol to the exponential phase, and its level drastically decreased in the cells grown to the stationary growth phase. A. vinelandii also overexpressed the glycerol-3-phosphate dehydrogenase gene when it was grown on glycerol. These results indicate that glycerol was first converted to glycerol-3-phosphate by glycerol kinase. Other molecules with industrial interests, such as lactic acid and amino acids including γ-aminobutyric acid, have also been accumulated in the bacterial cells grown on glycerol. Transmission electron microscopy revealed that glycerol-grown A. vinelandii stored PHB within the cells. The PHB production level reached 33% per dry cell weight in nitrogen-free glycerol medium. When grown on glycerol, alginate-overproducing mutants generated through chemical mutagenesis produced 2-fold the amount of alginate from glycerol than the parental wild-type strain. To the best of our knowledge, this is the first report on bacterial production of biopolymers from glycerol without addition of any nitrogen source. PMID:25880041

  5. Glycerol administration before endurance exercise: metabolism, urinary glycerol excretion and effects on doping-relevant blood parameters.

    PubMed

    Koehler, Karsten; Braun, Hans; de Marees, Markus; Geyer, Hans; Thevis, Mario; Mester, Joachim; Schaenzer, Wilhelm

    2014-03-01

    Glycerol is prohibited as a masking agent by the World Anti-Doping Agency and a urinary threshold has recently been recommended. However, little is known about urinary glycerol excretion after exercise, when (1) exogenous glycerol is metabolized increasingly and (2) endogenous glycerol levels are elevated. The purpose of the placebo-controlled cross-over study was to determine the effects of pre-exercise glycerol administration on glycerol metabolism, urinary excretion, and selected blood parameters. After administration of glycerol (G; 1.0 g/kg body weight (BW) + 25 ml fluid/kg BW) or placebo (P; 25 ml fluid/kg), 14 cyclists exercised 90 min at 60% VO2max . Samples were taken at 0 h (before administration), 2.5 h (before exercise), 4 h (after exercise) and 6.5 h and additional urine samples were collected until 24 h. Exercise increased endogenous plasma glycerol (0.51 ± 0.21 mmol/l) but peak concentrations were much higher in G (2.5 h: 15.6 ± 7.8 mmol/l). Urinary glycerol increased rapidly (58,428 ± 71,084 µg/ml after 2.5 h) and was significantly higher than in P until 13.6 ± 0.9 h (p < 0.01). In comparison with placebo administration, G caused significantly greater changes in plasma volume and haemoglobin concentrations after 2.5 h. BW and urine production were significantly different between P and G after 2.5 h and post-exercise. Despite exercise-induced increases in endogenous glycerol in the control group, urinary excretion remained well below the previously recommended threshold. In addition, exercise-related glycerol degradation did not appear to negatively affect the detection of exogenously administered glycerol. PMID:23359436

  6. Recent Advances in Glycerol Polymers: Chemistry and Biomedical Applications

    PubMed Central

    Zhang, Heng

    2015-01-01

    Glycerol polymers are attracting increased attention due to the diversity of polymer compositions and architectures available. This article provides a brief chronological review on the current status of these polymers along with representative examples of their use for biomedical applications. First, we describe the underlying chemistry of glycerol, which provides access to a range of monomers for subsequent polymerizations. We then review the various synthetic methodologies to prepare glycerol-based polymers including polyethers, polycarbonates, polyesters, and so forth. Next, we describe several biomedical applications where glycerol polymers are being investigated including carriers for drug delivery, sealants or coatings for tissue repair, and agents possessing antibacterial activity. Fourth, we describe the growing market opportunity for the use of polymers in medicine. Finally we conclude and summarize the findings, as well as discuss potential opportunities for continued research efforts. PMID:25308354

  7. Diffusion-viscosity decoupling in supercooled glycerol aqueous solutions.

    PubMed

    Trejo González, José A; Longinotti, M Paula; Corti, Horacio R

    2015-01-01

    The diffusion of ferrocene methanol in supercooled glycerol-water mixtures has been measured over a wide viscosity range, which allowed analyzing the composition dependence of the Stokes-Einstein breakdown (diffusion-viscosity decoupling). The observed decoupling exhibits a common behavior for all studied compositions (glycerol mass fractions between 0.7 and 0.9), determined by the reduced temperature (T/Tg) of the mixtures. This result differs from that reported previously for the diffusion of glycerol in its aqueous solutions, where the reduced temperature for the decoupling decreases with increasing water content. We conclude that the contradictory results are only apparent, and they can be explained by the use of inconsistent extrapolated values of the viscosity of the glycerol-water mixtures in the supercooled region. PMID:25478790

  8. Dehydration of glycerol over niobia-supported silicotungstic acid catalysts.

    PubMed

    Lee, Young Yi; Ok, Hye Jeong; Moon, Dong Ju; Kim, Jong Ho; Park, Nam Cook; Kim, Young Chul

    2013-01-01

    Liquid-phase dehydration of glycerol to acrolein over nanosized niobia-supported silicotungstic acid catalysts was performed to investigate the effect of the silicotungstic acid loading on the catalytic performance of the catalysts. The catalysts were prepared by following an impregnation method with different HSiW loadings in the range of 10-50 wt%. The prepared catalysts were characterized by N2 physisorption, XRD, FT-IR, TPD of ammonia, and TGA. Dehydration of glycerol was conducted in an autoclave reactor under the conditions of controlled reaction temperatures under corresponding pressure. Increasing HSiW loading rapidly increased the acidity of HSiW/Nb205 catalyst and rate of glycerol conversion, but acrolein selectivity decreased due to enhanced deactivation of the catalyst by carbon deposit. Consequently, it was confirmed that catalytic activity for the dehydration of glycerol to acrolein was dependant on the acidity of catalyst and can be controlled by HSiW loading. PMID:23646735

  9. Renewable hydrogen and carbon nanotubes from biodiesel waste glycerol

    PubMed Central

    Wu, Chunfei; Wang, Zichun; Williams, Paul T.; Huang, Jun

    2013-01-01

    In this report, we introduce a novel and commercially viable method to recover renewable hydrogen and carbon nanotubes from waste glycerol produced in the biodiesel process. Gas-phase catalytic reforming converts glycerol to clean hydrogen fuel and by replacing the problematical coke formed on the catalyst with high value carbon nanotubes, added value can be realised. Additional benefits of around 2.8 kg CNTs from the reforming of 1 tonne of glycerol and the production of 500 Nm3 H2 could have a considerable impact on the economics of glycerol utilization. Thereby, the contribution of this research will be a significant step forward in solving a current major technical and economic challenge faced by the biofuels industry. PMID:24067754

  10. Renewable hydrogen and carbon nanotubes from biodiesel waste glycerol.

    PubMed

    Wu, Chunfei; Wang, Zichun; Williams, Paul T; Huang, Jun

    2013-01-01

    In this report, we introduce a novel and commercially viable method to recover renewable hydrogen and carbon nanotubes from waste glycerol produced in the biodiesel process. Gas-phase catalytic reforming converts glycerol to clean hydrogen fuel and by replacing the problematical coke formed on the catalyst with high value carbon nanotubes, added value can be realised. Additional benefits of around 2.8 kg CNTs from the reforming of 1 tonne of glycerol and the production of 500 Nm(3) H2 could have a considerable impact on the economics of glycerol utilization. Thereby, the contribution of this research will be a significant step forward in solving a current major technical and economic challenge faced by the biofuels industry. PMID:24067754

  11. Plasma reforming of glycerol for synthesis gas production.

    PubMed

    Zhu, Xinli; Hoang, Trung; Lobban, Lance L; Mallinson, Richard G

    2009-05-28

    Glycerol can be effectively converted to synthesis gas (selectivity higher than 80%) with small amounts of water or no water using plasmas at low temperature and atmospheric pressure, without external heating. PMID:19436906

  12. Physicochemical characterization of oil palm mesocarp fibre treated with glycerol

    NASA Astrophysics Data System (ADS)

    Nor Hamizah M., A.; Roila, A.; Rahimi M., Y.

    2015-09-01

    Lignocellulose has been identified as another source for conversion into value added products. In the present work, physicochemical features from the oil palm mesocarp fibre treated by using pure glycerol with 2% (w/w) NaOH catalyst and crude glycerol have been studied. Treatment was conducted at temperatures 150 °C for 60 min. Fibre treated by crude glycerol resulted in high percentages of holocellulose and lower content of insoluble lignin. These results suggest that crude glycerol can be used as an alternative solvent for pretreatment process. The characterization treated fibre by means of FTIR and TGA has shown significant differences compared to untreated fibre. It was revealed that treated fibre successful eliminated hemicellulose and reduce of lignin content.

  13. [Role of the NADH shuttle system in glucose-induced insulin secretion].

    PubMed

    Eto, K; Kadowaki, T

    1999-03-01

    To determine the role of the NADH shuttle system composed of the glycerol phosphate shuttle and malate-aspartate shuttle in glucose-induced insulin secretion from pancreatic beta cells, we have generated mice which lack mitochondrial glycerol-3 phosphate dehydrogenase (mGPDH), a rate-limiting enzyme of the glycerol phosphate shuttle. When both shuttles were halted in mGPDH-deficient islets treated with aminooxyacetate, an inhibitor of the malate-aspartate shuttle, glucose-induced insulin secretion was almost completely abrogated. Under these conditions, although the flux of glycolysis and supply of glucose-derived pyruvate into mitochondria were unaffected, glucose-induced increases in NAD(P)H autofluorescence, mitochondrial membrane potential, Ca2+ entry into mitochondria, and ATP content were severely attenuated. This study provides the first direct evidence that the NADH shuttle system is essential for coupling glycolysis with the activation of mitochondrial energy metabolism to trigger glucose-induced insulin secretion and thus revises the classical model for the metabolic signals of glucose-induced insulin secretion. PMID:10199125

  14. A comparison of absorption of glycerol tristearate and glycerol trioleate by rat small intestine

    SciTech Connect

    Bergstedt, S.E.; Hayashi, H.; Kritchevsky, D.; Tso, P. )

    1990-09-01

    Generally, fats rich in saturated fatty acids raise serum cholesterol, whereas fats rich in polyunsaturated fatty acids lower it. There appear to be exceptions; e.g., stearic acid (18:0)-rich fats have little or no effect on serum cholesterol concentrations. This apparent lack of cholesterolemic effect of stearic acid-rich fat could be because intestinal absorption of fat is poor or subsequent plasma and/or tissue metabolism of fat is different. To investigate mechanisms involved, we compared intestinal digestion, uptake, and lymphatic transport of glycerol tristearate (TS) and glycerol trioleate (TO, 18:1). Two groups of rats bearing intestinal lymph fistulas were used. TO rats were fed intraduodenally for 8 h at a constant rate a lipid emulsion of 25 mumols/h of TO (labeled with glycerol tri(9,10 (n)-3H)oleate), 7.8 mumols of egg phosphatidylcholine, and 57 mumols of sodium taurocholate in 3 ml of phosphate-buffered saline. TS rats were fed the same lipid emulsion except that TS replaced TO and the emulsion was labeled with glyceryl (1,3-14C)tristearate. The lymph triglyceride and radioactivity were determined. After infusion, the luminal and mucosal radioactive lipid content was analyzed. The results showed that there was significantly less lipid transported in the lymph of TS rats compared with TO rats. The results also showed a significant decrease in the absorption of TS as compared with TO. This was due in part to poor lipolysis. In addition, the lipid absorbed by the intestine of the TS rats was transported into lymph less efficiently than in TO rats.

  15. Quantitative NMR Analysis of Partially Substituted Biodiesel Glycerols

    SciTech Connect

    Nagy, M.; Alleman, T. L.; Dyer, T.; Ragauskas, A. J.

    2009-01-01

    Phosphitylation of hydroxyl groups in biodiesel samples with 2-chloro-4,4,5,5-tetramethyl-1,3,2-dioxaphospholane followed by 31P-NMR analysis provides a rapid quantitative analytical technique for the determination of substitution patterns on partially esterified glycerols. The unique 31P-NMR chemical shift data was established with a series mono and di-substituted fatty acid esters of glycerol and then utilized to characterize an industrial sample of partially processed biodiesel.

  16. Optimizing aerobic conversion of glycerol to 3-hydroxypropionaldehyde

    SciTech Connect

    Slininger, P.J.; Bothast, R.J.

    1985-12-01

    Chemical oxidation of 3-hydroxypropionaldehyde (3-HPA) leads to acrylic acid, an industrially important polymerizable monomer currently derived from petroleum. As the availability of petroleum declines, 3-HPA may become attractive as a product to be obtained through fermentation of glycerol, a renewable resource. When cells of Klebsiella pneumoniae NRRL B-199 (ATCC 8724) were grown aerobically on a rich glycerol medium and then suspended in buffer supplemented with semicarbazide and glycerol, aerobic conversion of glycerol to 3-hydroxypropionaldehyde (3-HPA) ensued. Depending on conditions, 0.38 to 0.67 g of 3-HPA were formed per gram of glycerol consumed. This means that up to 83.8% of the carbon invested as glycerol could potentially be recovered as the target product, 3-HPA. Production of 3-HPA was sensitive to the age of cells harvested for resuspension and was nonexistent if cells were cultivated on glucose instead of glycerol as the sole carbon source. Compared with 24- and 72-h cells, 48-h cells produced 3-HPA at the highest rate and with the greatest yield. The cell biomass concentration present during the fermentation was never particularly critical to the 3-HPA yield, but initial fermentation rates and 3-HPA accumulation displayed a linear dependence on biomass concentration that faded when biomass exceeded 3 g/liter. Fermentation performance was a function of temperature, and an optimum initial specific 3-HPA productivity occurred at 32/sup 0/C, although the overall 3-HPA yield increased continuously within the 25 to 37/sup 0/C range studied. The pH optimum based on fermentation rate was different from that based on overall yield; 8 versus 7, respectively. Initial glycerol concentrations in the 20 to 50 g/liter range optimized initial 3-HPA productivity and yield.

  17. Identification of a mammalian glycerol-3-phosphate phosphatase: Role in metabolism and signaling in pancreatic β-cells and hepatocytes.

    PubMed

    Mugabo, Yves; Zhao, Shangang; Seifried, Annegrit; Gezzar, Sari; Al-Mass, Anfal; Zhang, Dongwei; Lamontagne, Julien; Attane, Camille; Poursharifi, Pegah; Iglesias, José; Joly, Erik; Peyot, Marie-Line; Gohla, Antje; Madiraju, S R Murthy; Prentki, Marc

    2016-01-26

    Obesity, and the associated disturbed glycerolipid/fatty acid (GL/FA) cycle, contribute to insulin resistance, islet β-cell failure, and type 2 diabetes. Flux through the GL/FA cycle is regulated by the availability of glycerol-3-phosphate (Gro3P) and fatty acyl-CoA. We describe here a mammalian Gro3P phosphatase (G3PP), which was not known to exist in mammalian cells, that can directly hydrolyze Gro3P to glycerol. We identified that mammalian phosphoglycolate phosphatase, with an uncertain function, acts in fact as a G3PP. We found that G3PP, by controlling Gro3P levels, regulates glycolysis and glucose oxidation, cellular redox and ATP production, gluconeogenesis, glycerolipid synthesis, and fatty acid oxidation in pancreatic islet β-cells and hepatocytes, and that glucose stimulated insulin secretion and the response to metabolic stress, e.g., glucolipotoxicity, in β-cells. In vivo overexpression of G3PP in rat liver lowers body weight gain and hepatic glucose production from glycerol and elevates plasma HDL levels. G3PP is expressed at various levels in different tissues, and its expression varies according to the nutritional state in some tissues. As Gro3P lies at the crossroads of glucose, lipid, and energy metabolism, control of its availability by G3PP adds a key level of metabolic regulation in mammalian cells, and G3PP offers a potential target for type 2 diabetes and cardiometabolic disorders. PMID:26755581

  18. Identification of a mammalian glycerol-3-phosphate phosphatase: Role in metabolism and signaling in pancreatic β-cells and hepatocytes

    PubMed Central

    Mugabo, Yves; Zhao, Shangang; Seifried, Annegrit; Gezzar, Sari; Al-Mass, Anfal; Zhang, Dongwei; Lamontagne, Julien; Attane, Camille; Poursharifi, Pegah; Iglesias, José; Joly, Erik; Peyot, Marie-Line; Gohla, Antje; Madiraju, S. R. Murthy; Prentki, Marc

    2016-01-01

    Obesity, and the associated disturbed glycerolipid/fatty acid (GL/FA) cycle, contribute to insulin resistance, islet β-cell failure, and type 2 diabetes. Flux through the GL/FA cycle is regulated by the availability of glycerol-3-phosphate (Gro3P) and fatty acyl-CoA. We describe here a mammalian Gro3P phosphatase (G3PP), which was not known to exist in mammalian cells, that can directly hydrolyze Gro3P to glycerol. We identified that mammalian phosphoglycolate phosphatase, with an uncertain function, acts in fact as a G3PP. We found that G3PP, by controlling Gro3P levels, regulates glycolysis and glucose oxidation, cellular redox and ATP production, gluconeogenesis, glycerolipid synthesis, and fatty acid oxidation in pancreatic islet β-cells and hepatocytes, and that glucose stimulated insulin secretion and the response to metabolic stress, e.g., glucolipotoxicity, in β-cells. In vivo overexpression of G3PP in rat liver lowers body weight gain and hepatic glucose production from glycerol and elevates plasma HDL levels. G3PP is expressed at various levels in different tissues, and its expression varies according to the nutritional state in some tissues. As Gro3P lies at the crossroads of glucose, lipid, and energy metabolism, control of its availability by G3PP adds a key level of metabolic regulation in mammalian cells, and G3PP offers a potential target for type 2 diabetes and cardiometabolic disorders. PMID:26755581

  19. Processes and systems for the production of propylene glycol from glycerol

    DOEpatents

    Frye, John G; Oberg, Aaron A; Zacher, Alan H

    2015-01-20

    Processes and systems for converting glycerol to propylene glycol are disclosed. The glycerol feed is diluted with propylene glycol as the primary solvent, rather than water which is typically used. The diluted glycerol feed is sent to a reactor where the glycerol is converted to propylene glycol (as well as other byproducts) in the presence of a catalyst. The propylene glycol-containing product from the reactor is recycled as a solvent for the glycerol feed.

  20. Value-added uses for crude glycerol--a byproduct of biodiesel production

    PubMed Central

    2012-01-01

    Biodiesel is a promising alternative, and renewable, fuel. As its production increases, so does production of the principle co-product, crude glycerol. The effective utilization of crude glycerol will contribute to the viability of biodiesel. In this review, composition and quality factors of crude glycerol are discussed. The value-added utilization opportunities of crude glycerol are reviewed. The majority of crude glycerol is used as feedstock for production of other value-added chemicals, followed by animal feeds. PMID:22413907

  1. Efficient synthetic protocols in glycerol under heterogeneous catalysis.

    PubMed

    Cravotto, Giancarlo; Orio, Laura; Gaudino, Emanuela Calcio; Martina, Katia; Tavor, Dorith; Wolfson, Adi

    2011-08-22

    The massive increase in glycerol production from the transesterification of vegetable oils has stimulated a large effort to find novel uses for this compound. Hence, the use of glycerol as a solvent for organic synthesis has drawn particular interest. Drawbacks of this green and renewable solvent are a low solubility of highly hydrophobic molecules and a high viscosity, which often requires the use of a fluidifying co-solvent. These limitations can be easily overcome by performing reactions under high-intensity ultrasound and microwaves in a stand-alone or combined manner. These non-conventional techniques facilitate and widen the use of glycerol as a solvent in organic synthesis. Glycerol allows excellent acoustic cavitation even at high temperatures (70-100 °C), which is otherwise negligible in water. Herein, we describe three different types of applications: 1) the catalytic transfer hydrogenation of benzaldehyde to benzyl alcohol in which glycerol plays the dual role of the solvent and hydrogen donor; 2) the palladium-catalyzed Suzuki cross-coupling; and (3) the Barbier reaction. In all cases glycerol proved to be a greener, less expensive, and safer alternative to the classic volatile organic solvents. PMID:21853535

  2. Key enzymes catalyzing glycerol to 1,3-propanediol.

    PubMed

    Jiang, Wei; Wang, Shizhen; Wang, Yuanpeng; Fang, Baishan

    2016-01-01

    Biodiesel can replace petroleum diesel as it is produced from animal fats and vegetable oils, and it produces about 10 % (w/w) glycerol, which is a promising new industrial microbial carbon, as a major by-product. One of the most potential applications of glycerol is its biotransformation to high value chemicals such as 1,3-propanediol (1,3-PD), dihydroxyacetone (DHA), succinic acid, etc., through microbial fermentation. Glycerol dehydratase, 1,3-propanediol dehydrogenase (1,3-propanediol-oxydoreductase), and glycerol dehydrogenase, which were encoded, respectively, by dhaB, dhaT, and dhaD and with DHA kinase are encompassed by the dha regulon, are the three key enzymes in glycerol bioconversion into 1,3-PD and DHA, and these are discussed in this review article. The summary of the main research direction of these three key enzyme and methods of glycerol bioconversion into 1,3-PD and DHA indicates their potential application in future enzymatic research and industrial production, especially in biodiesel industry. PMID:26966462

  3. Occurrence of glycerol uptake in Dunaliella tertiolecta under hyperosmotic stress.

    PubMed

    Lin, Huixin; Fang, Lei; Low, Chin Seng; Chow, Yvonne; Lee, Yuan Kun

    2013-02-01

    The unicellular halotolerant green alga species Dunaliella are able to proliferate in extremely varied salinities by synthesizing intracellular glycerol and adjusting the cell shape and volume. However, some marine Dunaliella species such as Dunaliella tertiolecta are not able to regulate cell volume as an immediate response to counter external osmotic shock. Here we report that a rapid shock-response mechanism is present in Dunaliella tertiolecta, involving uptake of exogenous glycerol in response to hyperosmotic shock without changing cell volume, and this glycerol uptake activity is associated with the Dunaliella tertiolecta glycerol uptake protein 1 (DtGUP1) gene, which belongs to the membrane-bound O-acyltransferase. The mutant DtGUP1-E, in which the DtGUP1 gene is silenced, displayed an inability to take up glycerol from the medium and showed cell death under hyperosmotic shock. To our knowledge, this is the first time a gene product has been reported in Dunaliella tertiolecta that is involved in glycerol uptake activity under hyperosmotic stress. PMID:23279806

  4. Microaerobic Conversion of Glycerol to Ethanol in Escherichia coli

    PubMed Central

    Wong, Matthew S.; Li, Mai; Black, Ryan W.; Le, Thao Q.; Puthli, Sharon; Campbell, Paul

    2014-01-01

    Glycerol has become a desirable feedstock for the production of fuels and chemicals due to its availability and low price, but many barriers to commercialization remain. Previous investigators have made significant improvements in the yield of ethanol from glycerol. We have developed a fermentation process for the efficient microaerobic conversion of glycerol to ethanol by Escherichia coli that presents solutions to several other barriers to commercialization: rate, titer, specific productivity, use of inducers, use of antibiotics, and safety. To increase the rate, titer, and specific productivity to commercially relevant levels, we constructed a plasmid that overexpressed glycerol uptake genes dhaKLM, gldA, and glpK, as well as the ethanol pathway gene adhE. To eliminate the cost of inducers and antibiotics from the fermentation, we used the adhE and icd promoters from E. coli in our plasmid, and we implemented glycerol addiction to retain the plasmid. To address the safety issue of off-gas flammability, we optimized the fermentation process with reduced-oxygen sparge gas to ensure that the off-gas remained nonflammable. These advances represent significant progress toward the commercialization of an E. coli-based glycerol-to-ethanol process. PMID:24584248

  5. Hydration and endocrine responses to intravenous fluid and oral glycerol.

    PubMed

    van Rosendal, S P; Strobel, N A; Osborne, M A; Fassett, R G; Coombes, J S

    2015-06-01

    Athletes use intravenous (IV) saline in an attempt to maximize rehydration. The diuresis from IV rehydration may be circumvented through the concomitant use of oral glycerol. We examined the effects of rehydrating with differing regimes of oral and IV fluid, with or without oral glycerol, on hydration, urine, and endocrine indices. Nine endurance-trained men were dehydrated by 4% bodyweight, then rehydrated with 150% of the fluid lost via four protocols: (a) oral = oral fluid only; (b) oral glycerol = oral fluid with added glycerol (1.5 g/kg); (c) IV = 50% IV fluid, 50% oral fluid; and (d) IV with oral glycerol = 50% IV fluid, 50% oral fluid with added glycerol (1.5 g/kg), using a randomized, crossover design. They then completed a cycling performance test. Plasma volume restoration was highest in IV with oral glycerol > IV > oral glycerol  > oral. Urine volume was reduced in both IV trials compared with oral. IV and IV with oral glycerol resulted in lower aldosterone levels during rehydration and performance, and lower cortisol levels during rehydration. IV with oral glycerol resulted in the greatest fluid retention. In summary, the IV conditions resulted in greater fluid retention compared with oral and lower levels of fluid regulatory and stress hormones compared with both oral conditions. PMID:25943662

  6. Authentication Without Secrets

    SciTech Connect

    Pierson, Lyndon G.; Robertson, Perry J.

    2015-11-01

    This work examines a new approach to authentication, which is the most fundamental security primitive that underpins all cyber security protections. Current Internet authentication techniques require the protection of one or more secret keys along with the integrity protection of the algorithms/computations designed to prove possession of the secret without actually revealing it. Protecting a secret requires physical barriers or encryption with yet another secret key. The reason to strive for "Authentication without Secret Keys" is that protecting secrets (even small ones only kept in a small corner of a component or device) is much harder than protecting the integrity of information that is not secret. Promising methods are examined for authentication of components, data, programs, network transactions, and/or individuals. The successful development of authentication without secret keys will enable far more tractable system security engineering for high exposure, high consequence systems by eliminating the need for brittle protection mechanisms to protect secret keys (such as are now protected in smart cards, etc.). This paper is a re-release of SAND2009-7032 with new figures numerous edits.

  7. The use of stable isotope-labeled glycerol and oleic acid to differentiate the hepatic functions of DGAT1 and -2

    PubMed Central

    Qi, Jenson; Lang, Wensheng; Geisler, John G.; Wang, Ping; Petrounia, Ioanna; Mai, Selyna; Smith, Charles; Askari, Hossein; Struble, Geoffrey T.; Williams, Robyn; Bhanot, Sanjay; Monia, Brett P.; Bayoumy, Shariff; Grant, Eugene; Caldwell, Gary W.; Todd, Matthew J.; Liang, Yin; Gaul, Micheal D.; Demarest, Keith T.; Connelly, Margery A.

    2012-01-01

    Diacylglycerol acyltransferase (DGAT) catalyzes the final step in triglyceride (TG) synthesis. There are two isoforms, DGAT1 and DGAT2, with distinct protein sequences and potentially different physiological functions. To date, the ability to determine clear functional differences between DGAT1 and DGAT2, especially with respect to hepatic TG synthesis, has been elusive. To dissect the roles of these two key enzymes, we pretreated HepG2 hepatoma cells with 13C3-D5-glycerol or 13C18-oleic acid, and profiled the major isotope-labeled TG species by liquid chromatography tandem mass spectrometry. Selective DGAT1 and DGAT2 inhibitors demonstrated that 13C3-D5-glycerol-incorporated TG synthesis was mediated by DGAT2, not DGAT1. Conversely, 13C18-oleoyl-incorporated TG synthesis was predominantly mediated by DGAT1. To trace hepatic TG synthesis and VLDL triglyceride (VLDL-TG) secretion in vivo, we administered D5-glycerol to mice and measured plasma levels of D5-glycerol-incorporated TG. Treatment with an antisense oligonucleotide (ASO) to DGAT2 led to a significant reduction in D5-glycerol incorporation into VLDL-TG. In contrast, the DGAT2 ASO had no effect on the incorporation of exogenously administered 13C18-oleic acid into VLDL-TG. Thus, our results indicate that DGAT1 and DGAT2 mediate distinct hepatic functions: DGAT2 is primarily responsible for incorporating endogenously synthesized FAs into TG, whereas DGAT1 plays a greater role in esterifying exogenous FAs to glycerol. PMID:22493088

  8. Quantitative Analysis of Phenylpropanoid Glycerol Glucosides in Different Organs of Easter Lily (Lilium longiflorum Thunb.).

    PubMed

    Munafo, John P; Gianfagna, Thomas J

    2015-05-20

    The Easter lily (Lilium longiflorum Thunb.) is esteemed worldwide as an attractive ornamental plant, and the flower buds and bulbs are used for both culinary and medicinal purposes in many parts of the world. L. longiflorum contains significant amounts of phenylpropanoid glycerol glucosides, a group of compounds that may contribute to plant pathogen defense, ultraviolet/high-intensity visible light (UV/high light) protection, and the purported medicinal uses of lilies. To define the natural distribution of these compounds within the plant, a liquid chromatography-mass spectrometry (LC-MS) method performed in selected ion monitoring (SIM) mode was employed for the quantitative analysis of five phenylpropanoid glycerol glucosides, namely, (2S)-1-O-caffeoyl-2-O-β-D-glucopyranosylglycerol, 1; (2R)-1-O-β-D-glucopyranosyl-2-O-p-coumaroylglycerol, 2; (2S)-1-O-p-coumaroyl-2-O-β-D-glucopyranosylglycerol, 3; (2S)-1-O-caffeoyl-2-O-β-D-glucopyranosyl-3-O-acetylglycerol, 4; and (2S)-1-O-p-coumaroyl-2-O-β-D-glucopyranosyl-3-O-acetylglycerol, 5, in the different organs of L. longiflorum. The p-coumaroyl-based 3 and its acetylated derivative 5 were determined to be the most abundant of the phenylpropanoid glycerol glucosides found in Easter lily bulbs, at 776.3 ± 8.4 and 650.7 ± 32.6 μg/g dry weight, respectively. The acetylated p-coumaroyl- and caffeoyl-based derivatives, 5 and 4, accumulated to the highest concentration in the closed flower buds, at 4925.2 ± 512.8 and 3216.8 ± 406.4 μg/g dry weight, respectively. Compound 4, followed by 5 and 1, proved to be the most abundant in the mature flowers, occurring at 6006.2 ± 625.8, 2160.3 ± 556.5, and 1535.8 ± 174.1 μg/g dry weight, respectively. Total concentrations of the phenylpropanoid glycerol glucosides were 10-100-fold higher in the above-ground plant organs as compared to the bulbs and fleshy roots. Two of the five compounds, 1 and 2, were identified in L. longiflorum for the first time. The quantitative

  9. Tubular Secretion in CKD.

    PubMed

    Suchy-Dicey, Astrid M; Laha, Thomas; Hoofnagle, Andrew; Newitt, Rick; Sirich, Tammy L; Meyer, Timothy W; Thummel, Ken E; Yanez, N David; Himmelfarb, Jonathan; Weiss, Noel S; Kestenbaum, Bryan R

    2016-07-01

    Renal function generally is assessed by measurement of GFR and urinary albumin excretion. Other intrinsic kidney functions, such as proximal tubular secretion, typically are not quantified. Tubular secretion of solutes is more efficient than glomerular filtration and a major mechanism for renal drug elimination, suggesting important clinical consequences of secretion dysfunction. Measuring tubular secretion as an independent marker of kidney function may provide insight into kidney disease etiology and improve prediction of adverse outcomes. We estimated secretion function by measuring secreted solute (hippurate, cinnamoylglycine, p-cresol sulfate, and indoxyl sulfate) clearance using liquid chromatography-tandem mass spectrometric assays of serum and timed urine samples in a prospective cohort study of 298 patients with kidney disease. We estimated GFR by mean clearance of creatinine and urea from the same samples and evaluated associations of renal secretion with participant characteristics, mortality, and CKD progression to dialysis. Tubular secretion rate modestly correlated with eGFR and associated with some participant characteristics, notably fractional excretion of electrolytes. Low clearance of hippurate or p-cresol sulfate associated with greater risk of death independent of eGFR (hazard ratio, 2.3; 95% confidence interval, 1.1 to 4.7; hazard ratio, 2.5; 95% confidence interval, 1.0 to 6.1, respectively). Hazards models also suggested an association between low cinnamoylglycine clearance and risk of dialysis, but statistical analyses did not exclude the null hypothesis. Therefore, estimates of proximal tubular secretion function correlate with glomerular filtration, but substantial variability in net secretion remains. The observed associations of net secretion with mortality and progression of CKD require confirmation. PMID:26614381

  10. Secrets to success.

    PubMed

    Sorrel, Amy Lynn

    2014-02-01

    A new national study reveals what it takes for physician practices to stay financially viable. Several Texas practices, among those rated as "better performers," share their secrets to success. One of those secrets, a physician says, is "hiring good people and getting out of their way." PMID:24500918

  11. Crude glycerol-based production of amino acids and putrescine by Corynebacterium glutamicum.

    PubMed

    Meiswinkel, Tobias M; Rittmann, Doris; Lindner, Steffen N; Wendisch, Volker F

    2013-10-01

    Corynebacterium glutamicum possesses genes for glycerol kinase and glycerol-3-phosphate dehydrogenase that were shown to support slow growth with glycerol only when overexpressed from a plasmid. Pure glycerol and crude glycerol from biodiesel factories were tested for growth of recombinant strains expressing glpF, glpK and glpD from Escherichia coli. Some, but not all crude glycerol lots served as good carbon sources. Although the inhibitory compound(s) present in these crude glycerol lots remained unknown, the addition of substoichiometric glucose concentrations (below 10% by weight) enabled the utilization of some of the inhibitory crude glycerol lots. Besides growth, production of the amino acids L-glutamate, L-lysine, L-ornithine and L-arginine as well as of the diamine putrescine based on crude glycerol qualities from biodiesel factories was demonstrated. PMID:23562176

  12. Engineering of a glycerol utilization pathway for amino acid production by Corynebacterium glutamicum.

    PubMed

    Rittmann, Doris; Lindner, Steffen N; Wendisch, Volker F

    2008-10-01

    The amino acid-producing organism Corynebacterium glutamicum cannot utilize glycerol, a stoichiometric by-product of biodiesel production. By heterologous expression of Escherichia coli glycerol utilization genes, C. glutamicum was engineered to grow on glycerol. While expression of the E. coli genes for glycerol kinase (glpK) and glycerol 3-phosphate dehydrogenase (glpD) was sufficient for growth on glycerol as the sole carbon and energy source, additional expression of the aquaglyceroporin gene glpF from E. coli increased growth rate and biomass formation. Glutamate production from glycerol was enabled by plasmid-borne expression of E. coli glpF, glpK, and glpD in C. glutamicum wild type. In addition, a lysine-producing C. glutamicum strain expressing E. coli glpF, glpK, and glpD was able to produce lysine from glycerol as the sole carbon substrate as well as from glycerol-glucose mixtures. PMID:18757581

  13. Glycerol dehydrates oedematous as well as normal brain in dogs.

    PubMed

    Wang, J Y; Chen, J L

    1994-04-01

    1. Although the effect of glycerol on reducing intracranial pressure has been widely investigated, only a few studies have reported its dehydrating effect on brain oedema caused by infarction, ischaemia, microembolism and cold injury, but none on traumatic oedema. In this study the effects of glycerol (1 g/kg, i.v. bolus infusion at a rate of 0.04 g/kg per min) on traumatic and cryogenic cerebral oedema and on normal brain were compared in the anaesthetized dog. The tissue water content was measured with the gravimetric method. 2. Oedema resulting from mechanical trauma was initiated 4 h prior to treatment with glycerol (8 dogs) or vehicle (5 dogs) by closed head contusion with fixed force under general anaesthesia. Tissue samples underneath the region of contusion were taken, before and 1 h after infusion of glycerol or vehicle, for the measurement of water content. 3. Glycerol infusion decreased the water content in white matter of the traumatic brain model from 76.54 +/- 1.70% to 70.73 +/- 1.54% (P < 0.001). In normal brain the reduction was from 68.42 +/- 0.48% to 65.36 +/- 0.39% (P < 0.001). Neither vehicle nor glycerol infusion resulted in significant changes in specific gravity of the gray matter. 4. Cryogenic oedema was initiated 3 h prior to the infusion of glycerol or vehicle by applying unilaterally a brass conical cup (bottom diameter 1 cm) filled with dry ice-acetone (-65 degrees C) to the exposed dura for 1 min. The contralateral hemisphere, which was not subjected to cold injury, was used for determination of water content of normal gray and white matter. 5. Glycerol infusion decreased the water content in the white matter of the cold-injured region from 75.38 +/- 0.69% to 72.57 +/- 0.58% (P < 0.001). In the normal white matter the reduction was from 68.63 +/- 0.34% to 65.48 +/- 0.49% (P < 0.001). 6. Our data indicate that glycerol decreases water content of the white matter in traumatic and cold-injured oedematous brain as well as in normal brain

  14. Dysferlin and Myoferlin Regulate Transverse Tubule Formation and Glycerol Sensitivity

    PubMed Central

    Demonbreun, Alexis R.; Rossi, Ann E.; Alvarez, Manuel G.; Swanson, Kaitlin E.; Deveaux, H. Kieran; Earley, Judy U.; Hadhazy, Michele; Vohra, Ravneet; Walter, Glenn A.; Pytel, Peter; McNally, Elizabeth M.

    2015-01-01

    Dysferlin is a membrane-associated protein implicated in muscular dystrophy and vesicle movement and function in muscles. The precise role of dysferlin has been debated, partly because of the mild phenotype in dysferlin-null mice (Dysf). We bred Dysf mice to mice lacking myoferlin (MKO) to generate mice lacking both myoferlin and dysferlin (FER). FER animals displayed progressive muscle damage with myofiber necrosis, internalized nuclei, and, at older ages, chronic remodeling and increasing creatine kinase levels. These changes were most prominent in proximal limb and trunk muscles and were more severe than in Dysf mice. Consistently, FER animals had reduced ad libitum activity. Ultrastructural studies uncovered progressive dilation of the sarcoplasmic reticulum and ectopic and misaligned transverse tubules in FER skeletal muscle. FER muscle, and Dysf- and MKO-null muscle, exuded lipid, and serum glycerol levels were elevated in FER and Dysf mice. Glycerol injection into muscle is known to induce myopathy, and glycerol exposure promotes detachment of transverse tubules from the sarcoplasmic reticulum. Dysf, MKO, and FER muscles were highly susceptible to glycerol exposure in vitro, demonstrating a dysfunctional sarcotubule system, and in vivo glycerol exposure induced severe muscular dystrophy, especially in FER muscle. Together, these findings demonstrate the importance of dysferlin and myoferlin for transverse tubule function and in the genesis of muscular dystrophy. PMID:24177035

  15. Glycerol use in hyperhydration and rehydration: scientific update.

    PubMed

    van Rosendal, S P; Coombes, J S

    2012-01-01

    Glycerol ingestion creates an osmotic drive that enhances fluid retention. The major practical applications for athletes are to either (i) hyperhydrate before exercise so that they have more fluid to be lost as sweat during subsequent performance, thereby delaying the progression of dehydration from becoming physiologically significant, or (ii) improve both the rate of rehydration and total fluid retention following exercise. Recently we showed that rehydration may be improved further by combining glycerol with intravenous fluids. Improvements in endurance time, time trial performance and total power and work output have been seen during exercise following glycerol-induced hyperhydration or rehydration. Another recent trial showed that the increased body weight associated with the extra fluid does not inadvertently affect running economy. Concerns that the haemodilution associated with the fluid retention in the vascular space may be sufficient to mask illegal doping practices by athletes led the World Anti-Doping Agency (WADA) to add glycerol to its list of prohibited substances in 2010. Recent evidence suggests that doses of > 0.032 ± 0.010 g/kg lean body mass (much lower than those required for rehydration) will result in urinary excretion that may be detectable, so athletes under the WADA jurisdiction should be cautious to limit their inadvertent glycerol intake. PMID:23075560

  16. Treatment of glycerol phase formed by biodiesel production.

    PubMed

    Hájek, Martin; Skopal, Frantisek

    2010-05-01

    Glycerol is a by-product of biodiesel produced by transesterification and is contained in the glycerol phase together with many other materials such as soaps, remaining catalyst, water, and esters formed during the process. The content of glycerol is approximately 30-60 wt.%. In this paper, treatments of the glycerol phase to obtain glycerol with a purity of 86 wt.% (without distillation) and a mixture of fatty acids with esters (1:1) or only a mixture of fatty acids with a purity of 99 wt.% are presented. The treatment was carried out by removing of alkaline substances and esters. Fatty acids were produced by saponification of the remaining esters and subsequent neutralization of alkaline substances by phosphoric, sulfuric, hydrochloric, or acetic acids. Salts are by-products and, in the case of phosphoric acid can be used as potash-phosphate fertilizer. The process of treatment is easy and environmentally friendly, because no special chemicals or equipment are required and all products are utilizable. PMID:20074939

  17. Thermodynamics of interdigitated phases of phosphatidylcholine in glycerol.

    PubMed Central

    Swamy, M J; Marsh, D

    1995-01-01

    Comparison of the electron spin resonance spectra of phosphatidylcholines spin-labeled in the sn-2 chain at a position close to the polar region and close to the methyl terminus indicate that symmetrical saturated diacyl phosphatidylcholines with odd and even chain lengths from 13 to 20 C-atoms (and probably also 12 C-atoms) have gel phases in which the chains are interdigitated when dispersed in glycerol. The chain-length dependences of the chain-melting transition enthalpies and entropies are similar for phosphatidylcholines dispersed in glycerol and in water, but the negative end contributions are smaller for phosphatidylcholines dispersed in glycerol than for those dispersed in water: d delta Ht/dCH2 = 1.48 (1.43) kcal.mol-1, d delta St/dCH2 = 3.9 (4.0) cal.mol-1K-1, and delta H o = -12.9 (-15.0) kcal.mol-1, delta S o = -29 (-40) cal.mol-1K-1, respectively, for dispersions in glycerol (water). These differences reflect the interfacial energetics in glycerol and in water, and the different structure of the interdigitated gel phase. PMID:8534810

  18. Determination of optimal glycerol concentration for optical tissue clearing

    NASA Astrophysics Data System (ADS)

    Youn, Eungjun; Son, Taeyoon; Kim, Han-Sung; Jung, Byungjo

    2012-02-01

    The laser scattering in tissue is significant in diagnostic and therapeutic purposes of laser. Many studies have been conducted to minimize laser scattering in tissue and therefore, to maximize the clinical efficacy by enhancing photon density. Optical clearing agents (OCAs) have been employed for optical tissue clearing (OTC). This study was aimed to investigate the optimal concentration of an OCA, glycerol, in topical application,, so that it can be utilized for clinical diagnosis and therapy in dermatology. Glycerol was topically applied to avoid possible edema caused by dermal injection. The effect of OTC was quantitatively evaluated as a function of the concentration of glycerol with various methods. Optical methods such as optical coherence tomography (OCT) and an integrating sphere were used to assess the enhancement of light penetration depth and refractive index matching. In addition, a non-optical method, ultrasound scanner, was utilized to evaluate quantitatively collagen dissociation. The results revealed that 70 % glycerol was the optimal concentration of OTC for topical application. This study may provide a guideline regarding to the use of glycerol for optimal diagnostic and therapeutic effects in dermatology.

  19. The structure of GlpF, a glycerol conducting channel.

    PubMed

    Fu, Dax; Libson, Andrew; Stroud, Robert

    2002-01-01

    The passage of water or small neutral solutes across the cell membrane in animals, plants and bacteria is facilitated by a family of homologous membrane channels, variously known as aquaporins though perhaps more correctly as aquaglyceroporins. The glycerol facilitator (GlpF) is a 28 kDa aquaglyceroporin that catalyses transmembrane diffusion of glycerol and certain linear polyhydric alcohols in Escherichia coli. X-ray crystallographic analysis of GlpF to 2.2 A resolution revealed an alpha-barrel structure, surrounded by six full-length transmembrane helices and two half-spanning helices that are joined head-to-head in the middle of the membrane. These helices are arranged to a quasi twofold manner relative to the central membrane plane, where highly conserved residues make helix-to-helix contacts that stabilize the relative position and orientation of the helices in the structure. This sequence-structure correlation suggests that the evolutionary divergence of aquaporins and aquaglyceroporins is constrained by a conserved structural framework within which specialized function may be developed. Three glycerol molecules were resolved in the central channel through the GlpF monomer, thereby defining a transmembrane channel for glycerol permeation. The structure of glycerol GlpF complex provides insight into the chemical basis for transmembrane selective permeability. PMID:12027015

  20. Synthesis of monophytanyl ether analogues of lysophosphatidic and lysophosphatidyl glycerol.

    PubMed

    Kates, M; Hancock, A J

    1976-10-01

    The chemical synthesis of 3-O-phytanyl-sn-glycero-1-phosphoric acid (monophytanyl ether analogue of lysophosphatidic acid) was effected by condensation of 1-iodo-2-O-benzyl-3-O-phytanyl-sn-glycerol with silver di-p-nitrobenzyl phosphate in anhydrous toluene followed by catalytic hydrogenolysis of the resulting phosphotriester to remove the benzyl and p-nitrobenzyl groups. Synthesis of 3-O-phytanyl-sn-glycero-1-phosphoryl-1'-sn-glycerol (monophytanyl ether analogue of lysophosphatidyl glycerol) was carried out by conversion of the above phosphotriester to the monosilver salt of the suitably blocked lysophosphatidic acid which was condensed with 1-iodo-2-O-t-butyl-3-O-benzyl-sn-glycerol. Removal of the protecting aromatic and t-butyl groups from the resulting blocked triester intermediate gave the desired phytanyl ether analogue of lysophosphatidyl glycerol. Both lyso analogues were isolated as analytically and chromatographically pure potassium salts. Their physical properties and behavior towards acid hydrolysis are described. PMID:991376

  1. Effect of NaCl on the accumulation of glycerol by three Aspergillus species.

    PubMed

    Zidan, M A; Abdel-Mallek, A Y

    1987-01-01

    The accumulation of glycerol was investigated in three Aspergillus species, A. niger, A. ochraceus and A. tamarii after being grown in media containing different NaCl concentrations. Intra-extracellular as well as total glycerol were markedly accumulated by the three organisms in response to increased salinity. However, at salinity levels of 10-14% NaCl, extracellular glycerol was somewhat lowered. In addition, it was found that the maximum accumulation of glycerol in A. niger and A. tamarii was reached within the first 10 hours after salinization. However, after desalinization, the extracellular glycerol was continuously increased within the first 6 hours at the expense of intracellular glycerol. PMID:3449615

  2. Water availability determines branched glycerol dialkyl glycerol tetraether distributions in soils of the Iberian Peninsula

    NASA Astrophysics Data System (ADS)

    Menges, J.; Huguet, C.; Alcañiz, J. M.; Fietz, S.; Sachse, D.; Rosell-Melé, A.

    2013-06-01

    The MBT/CBT has recently gained significant attention as a novel paleotemperature proxy. It is based on the distribution of branched glycerol dialkyl glycerol tetraethers (GDGTs) in soils. The CBT quantifies the degree of cyclisation and relates to soil pH. The MBT' quantifies the degree of methylation and relates to mean annual temperature and soil pH. Combining these two indices allows estimation of mean annual temperature (MAT). However other factors such as soil water availability or moisture conditions have been suggested to influence the MBT'. To assess the effect of moisture conditions on the MBT'/CBT a set of 23 Iberian Peninsula soil samples covering a temperature range from 10-18 °C and a wide range of soil moisture regimes (405 mm to 1455 mm mean annual precipitation per year), was analyzed. We find that CBT is significantly correlated to soil pH confirming it as a robust proxy. In contrast the MBT' index was not correlated to MAT and was weakly correlated to annual mean precipitation (MAP). Instead we found a significant correlation between MBT' and the Aridity Index (AI), a parameter related to water availability in soils. The AI can explain 70% of the residuals of MAT estimation and 50% of the actual variation of the MBT'. This suggests that in dry environments or under moisture shortage the degree of methylation of branched GDGTs is not controlled by temperature but rather by the degree of water available. Our results suggest that the MBT/CBT index is not applicable as a paleotemperature proxy in dry subhumid to hyperarid environments.

  3. In situ production of branched glycerol dialkyl glycerol tetraethers in a great basin hot spring (USA)

    PubMed Central

    Zhang, Chuanlun L.; Wang, Jinxiang; Dodsworth, Jeremy A.; Williams, Amanda J.; Zhu, Chun; Hinrichs, Kai-Uwe; Zheng, Fengfeng; Hedlund, Brian P.

    2013-01-01

    Branched glycerol dialkyl glycerol tetraethers (bGDGTs) are predominantly found in soils and peat bogs. In this study, we analyzed core (C)-bGDGTs after hydrolysis of polar fractions using liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry and analyzed intact P-bGDGTs using total lipid extract (TLE) without hydrolysis by liquid chromatography-electrospray ionization-multiple stage mass spectrometry. Our results show multiple lines of evidence for the production of bGDGTs in sediments and cellulolytic enrichments in a hot spring (62–86°C) in the Great Basin (USA). First, in situ cellulolytic enrichment led to an increase in the relative abundance of hydrolysis-derived P-bGDGTs over their C-bGDGT counterparts. Second, the hydrolysis-derived P- and C-bGDGT profiles in the hot spring were different from those of the surrounding soil samples; in particular, a monoglycosidic bGDGT Ib containing 13,16-dimethyloctacosane and one cyclopentane moiety was detected in the TLE but it was undetectable in surrounding soil samples even after sample enrichments. Third, previously published 16S rRNA gene pyrotag analysis from the same lignocellulose samples demonstrated the enrichment of thermophiles, rather than mesophiles, and total bGDGT abundance in cellulolytic enrichments correlated with the relative abundance of 16S rRNA gene pyrotags from thermophilic bacteria in the phyla Bacteroidetes, Dictyoglomi, EM3, and OP9 (“Atribacteria”). These observations conclusively demonstrate the production of bGDGTs in this hot spring; however, the identity of organisms that produce bGDGTs in the geothermal environment remains unclear. PMID:23847605

  4. Accelerated dynamics of supercooled glycerol in soft confinement

    NASA Astrophysics Data System (ADS)

    Blochowicz, T.; Gouirand, E.; Fricke, A.; Spehr, T.; Stühn, B.; Frick, B.

    2009-06-01

    We investigate the dynamics of supercooled glycerol in a soft confinement within microemulsion droplets. The structure of the system is characterized by small-angle neutron scattering. We show that temperature-stable droplets establish a confinement, which may be varied in size from about 1 to 10 nm. Subsequently we focus on the dynamics of glass-forming glycerol confined within nanodroplets of different sizes. By combining neutron backscattering and time-of-flight for a broad dynamic range we obtain the incoherent intermediate scattering function S(q,t), which reveals increasingly accelerated dynamics as glycerol is confined to smaller droplets and for the relaxation times a crossover from Vogel-Fulcher behavior in the bulk to an Arrhenius law in confinement.

  5. Ru/FTO: Heterogeneous catalyst for glycerol hydrogenolysis

    NASA Astrophysics Data System (ADS)

    Samad, Wan Zurina; Isahak, Wan Nor Roslam Wan; Liew, Kin Hong; Nordin, Norazzizi; Yarmo, Mohd Ambar; Yusop, Muhammad Rahimi

    2014-09-01

    An introduction of Fluorine-doped tin oxide (FTO) as new catalyst support with Ru metal had enhanced the conversion and selectivity for glycerol hydrogenolysis. A small cluster of Ru were highly dispersed and intercalated over FTO via simple chemical mixture and reduction method. In comparison with various metal (Pd, Os, Cu), Ru/FTO catalyst showed the highest conversion (100%) and highly selectivity of 1,2-propanediol (94%) in the hydrogenolysis of glycerol. The reaction was optimally conducted at 150 °C, 20 bar of H2 pressure and at 8 hours. Ru/FTO catalyst was ascribed as active catalyst due to the amphoteric sites of FTO and small size of Ru metal. This provides high surface concentration of reduction process that involves the chemical bond dissociation in the glycerol hydrogenolysis.

  6. Enhanced production of 3-hydroxypropionic acid from glycerol by modulation of glycerol metabolism in recombinant Escherichia coli.

    PubMed

    Kim, Kwangwook; Kim, Sun-Ki; Park, Yong-Cheol; Seo, Jin-Ho

    2014-03-01

    3-Hydroxypropionic acid (3-HP) is a valuable biochemical with high potential for bioplastic manufacturing. The endogenous glycerol metabolism and by-product formation pathway in Escherichia coli were modulated to enhance 3-HP production from glycerol. Double deletion of glpK and yqhD directed the glycerol flux to 3-HP biosynthesis and reduced the formation of 1,3-propanediol. Since 3-hydroxypropionaldehyde (3-HPA), a precursor of 3-HP, is toxic to cell growth, the gene encoding Pseudomonas aeruginosa semialdehyde dehydrogenase (PSALDH) highly active on 3-HPA was expressed in E. coli. Finally, fed-batch culture of recombinant E. coli BL21star(DE3) without glpK and yqhD, and expressing Lactobacillus brevis DhaB-DhaR, and P. aeruginosa PSALDH resulted in 57.3g/L 3-HP concentration, 1.59g/L-h productivity and 0.88g/g yield. In conclusion, modulation of the glycerol metabolism in combination with enhanced activity of 3-HPA dehydrogenation improved the production of 3-HP from glycerol. PMID:24502915

  7. Effect of biodiesel-derived raw glycerol on 1,3-propanediol production by different microorganisms.

    PubMed

    Moon, Chuloo; Ahn, Jae-Hyeong; Kim, Seung W; Sang, Byoung-In; Um, Youngsoon

    2010-05-01

    The microbial production of 1,3-propanediol (1,3-PD) from raw glycerol, a byproduct of biodiesel production, is economically and environmentally advantageous. Although direct use of raw glycerol without any pretreatment is desirable, previous studies have reported that this could cause inhibition of microbial growth. In this study, we investigated the effects of raw glycerol type, different microorganisms, and pretreatment of raw glycerol on the production of 1,3-PD. Raw glycerol from waste vegetable-oil-based biodiesel production generally caused more inhibition of 1,3-PD production and microbial growth compared to raw glycerol from soybean-oil-based biodiesel production. In addition, two raw glycerol types produced from two biodiesel manufacturers using waste vegetable oil exhibited different 1,3-PD production behavior, partially due to different amounts of methanol included in the raw glycerol from the two biodiesel manufacturers. Klebsiella strains were generally resistant to all types of raw glycerol while the growth of Clostridium strains was variably inhibited depending on the type of raw glycerol. The 1,3-PD production of the Clostridium strains using acid-pretreated raw glycerol was significantly enhanced compared to that with raw glycerol, demonstrating the feasibility of using raw glycerol for 1,3-PD production by various microorganisms. PMID:19937397

  8. Pulse loading of glycerol by electric explosion of wire

    NASA Astrophysics Data System (ADS)

    Uvarov, S. V.; Bannikova, I. A.; Naimark, O. B.

    2015-11-01

    A series of experiments was carried out to investigate the relaxation properties of glycerol under shock-wave loading. The strain rates at the compression wave front were in the range of 105-107 s-1. A modified version of the wire explosion set-up was used. Free surface velocity profiles were recorded by VISAR with fiber-optic sensor. We found that the glycerol exhibits the non-Newtonian liquid behavior: viscosity is higher at the high strain rate. Strain rate at the compressive wave front is found to be dependent on the wave amplitude in power of 1.3.

  9. Propylene from renewable resources: catalytic conversion of glycerol into propylene.

    PubMed

    Yu, Lei; Yuan, Jing; Zhang, Qi; Liu, Yong-Mei; He, He-Yong; Fan, Kang-Nian; Cao, Yong

    2014-03-01

    Propylene, one of the most demanded commodity chemicals, is obtained overwhelmingly from fossil resources. In view of the diminishing fossil resources and the ongoing climate change, the identification of new efficient and alternative routes for the large-scale production of propylene from biorenewable resources has become essential. Herein, a new selective route for the synthesis of propylene from bio-derived glycerol is demonstrated. The route consists of the formation of 1-propanol (a versatile bulk chemical) as intermediate through hydrogenolysis of glycerol at a high selectivity. A subsequent dehydration produces propylene. PMID:24578188

  10. Cryoprotective effect of different glycerol concentrations on domestic cat spermatozoa.

    PubMed

    Villaverde, Ana Izabel S Balbin; Fioratti, Eduardo G; Penitenti, Marcimara; Ikoma, Maura R V; Tsunemi, Miriam H; Papa, Frederico O; Lopes, Maria D

    2013-10-15

    Cryopreservation of spermatozoa is a pivotal tool in assisted reproduction, and studies aiming to establish optimal freezing/thawing protocols are essential to enhance sperm survival. The objectives of the present study were to (1) compare the cryoprotective efficiency of three different glycerol concentrations (3%, 5%, and 7%) on the basis of post-thaw sperm quality and (2) investigate whether the incidence of morphologically abnormal sperm in fresh samples is related to cryodamage sensitivity. Semen was collected from six tomcats using an artificial vagina (total 18 ejaculates). Each ejaculate was diluted using Tris-egg yolk-based extender (TEY), evaluated, equally divided into three aliquots, and rediluted using TEY with and without glycerol to achieve final concentrations of 3%, 5%, and 7%. Samples were loaded into 0.25 mL straws, equilibrated for 60 minutes at 5 °C, frozen, and then thawed at 46 °C for 12 seconds. Fresh and frozen-thawed samples were evaluated for sperm motion parameters (computer-assisted sperm analysis), plasma membrane integrity (PMI; propidium iodide and carboxyfluorescein diacetate), and DNA integrity (acridine orange). Plasma and acrosomal membrane integrity were assessed by flow cytometry (propidium iodide and fluorescein isothiocyanate-conjugated pea (Pisum sativum) agglutinin) immediately after thawing. Sperm motion parameters were also evaluated at 30 and 60 minutes of postincubation. For all treatment groups, cryopreservation significantly impaired the PMI and sperm motion parameters, except for straightness and amplitude of lateral head displacement. DNA integrity showed a slight reduction (P < 0.05) when 3% glycerol was used. The percentage of total motility, progressive motility, and rapid spermatozoa were significantly lower immediately after thawing and up to 60 minutes of incubation for the 3% glycerol group when compared with 5% and 7%. No difference (P > 0.05) was found for PMI, acrosome integrity, and DNA integrity among

  11. Dielectric and specific heat relaxations in vapor deposited glycerol.

    PubMed

    Kasina, A; Putzeys, T; Wübbenhorst, M

    2015-12-28

    Recently [S. Capponi, S. Napolitano, and M. Wübbenhorst, Nat. Commun. 3, 1233 (2012)], vapor deposited glasses of glycerol have been found to recover their super-cooled liquid state via a metastable, ordered liquid (MROL) state characterized by a tremendously enhanced dielectric strength along with a slow-down of the relaxation rate of the structural relaxation. To study the calorimetric signature of this phenomenon, we have implemented a chip-based, differential AC calorimeter in an organic molecular beam deposition setup, which allows the simultaneous measurement of dielectric relaxations via interdigitated comb electrodes and specific heat relaxation spectra during deposition and as function of the temperature. Heating of the as-deposited glass just above the bulk Tg and subsequent cooling/reheating revealed a step-wise increase in cp by in total 9%, indicating unambiguously that glycerol, through slow vapour deposition, forms a thermodynamically stable glass, which has a specific heat as low as that of crystalline glycerol. Moreover, these glasses were found to show excellent kinetic stability as well as evidenced by both a high onset-temperature and quasi-isothermal recovery measurements at -75 °C. The second goal of the study was to elucidate the impact of the MROL state on the specific heat and its relaxation to the super-cooled state. Conversion of "MROL glycerol" to its "normal" (ordinary liquid, OL) state revealed a second, small (∼2%) increase of the glassy cp, a little gain (<10%) in the relaxed specific heat, and no signs of deviations of τcal from that of normal "bulk" glycerol. These findings altogether suggest that the MROL state in glycerol comprises largely bulk-type glycerol that coexist with a minor volume fraction (<10%) of PVD-induced structural anomalies with a crystal-like calorimetric signature. Based on the new calorimetric findings, we have proposed a new physical picture that assumes the existence of rigid polar clusters (RPCs

  12. Secret quality of love.

    PubMed

    Strachan-Hall, Elaine

    2016-09-01

    Many of us can recite three Donabedian dimensions of the quality of care of structure, process and outcome. Recently, I was introduced to another of Avedis Donabedian's quotes about the 'secret quality of love'. PMID:27581908

  13. Six secrets of champagne

    NASA Astrophysics Data System (ADS)

    Liger-Belair, Gérard

    2015-12-01

    Popping open a bottle of champagne is one of life's great delights, but how much do you really know about the science behind this greatest of wines? Gérard Liger-Belair reveals his six favourite champagne secrets.

  14. Efficient quantum secret sharing

    NASA Astrophysics Data System (ADS)

    Qin, Huawang; Dai, Yuewei

    2016-05-01

    An efficient quantum secret sharing scheme is proposed, in which the dealer generates some single particles and then uses the operations of quantum-controlled-not and Hadamard gate to encode a determinate secret into these particles. The participants get their shadows by performing the single-particle measurements on their particles, and even the dealer cannot know their shadows. Compared to the existing schemes, our scheme is more practical within the present technologies.

  15. Freeze resistance in rainbow smelt (Osmerus mordax): seasonal pattern of glycerol and antifreeze protein levels and liver enzyme activity associated with glycerol production.

    PubMed

    Lewis, Johanne M; Ewart, K Vanya; Driedzic, William R

    2004-01-01

    Rainbow smelt (Osmerus mordax) inhabit inshore waters along the North American Atlantic coast. During the winter, these waters are frequently ice covered and can reach temperatures as low as -1.9 degrees C. To prevent freezing, smelt accumulate high levels of glycerol, which lower the freezing point via colligative means, and antifreeze proteins (AFP). The up-regulation of the antifreeze response (both glycerol and AFP) occurs in early fall, when water temperatures are 5 degrees -6 degrees C. The accumulation of glycerol appears to be the main mechanism of freeze resistance in smelt because it contributes more to the lowering of the body's freezing point than the activity of the AFP (0.5 degrees C vs. 0.25 degrees C for glycerol and AFP, respectively) at a water temperature of -1.5 degrees C. Moreover, AFP in smelt appears to be a safeguard mechanism to prevent freezing when glycerol levels are low. Significant increases in activities of the liver enzymes glycerol 3-phosphate dehydrogenase (GPDH), alanine aminotransferase (AlaAT), and phosphoenolpyruvate carboxykinase (PEPCK) during the initiation of glycerol production and significant correlations between enzyme activities and plasma glycerol levels suggest that these enzymes are closely associated with the synthesis and maintenance of elevated glycerol levels for use as an antifreeze. These findings add further support to the concept that carbon for glycerol is derived from amino acids. PMID:15286915

  16. Characterization of a Novel Intestinal Glycerol-3-phosphate Acyltransferase Pathway and Its Role in Lipid Homeostasis.

    PubMed

    Khatun, Irani; Clark, Ronald W; Vera, Nicholas B; Kou, Kou; Erion, Derek M; Coskran, Timothy; Bobrowski, Walter F; Okerberg, Carlin; Goodwin, Bryan

    2016-02-01

    Dietary triglycerides (TG) are absorbed by the enterocytes of the small intestine after luminal hydrolysis into monacylglycerol and fatty acids. Before secretion on chylomicrons, these lipids are reesterified into TG, primarily through the monoacylglycerol pathway. However, targeted deletion of the primary murine monoacylglycerol acyltransferase does not quantitatively affect lipid absorption, suggesting the existence of alternative pathways. Therefore, we investigated the role of the glycerol 3-phosphate pathway in dietary lipid absorption. The expression of glycerol-3-phosphate acyltransferase (GPAT3) was examined throughout the small intestine. To evaluate the role for GPAT3 in lipid absorption, mice harboring a disrupted GPAT3 gene (Gpat3(-/-)) were subjected to an oral lipid challenge and fed a Western-type diet to characterize the role in lipid and cholesterol homeostasis. Additional mechanistic studies were performed in primary enterocytes. GPAT3 was abundantly expressed in the apical surface of enterocytes in the small intestine. After an oral lipid bolus, Gpat3(-/-) mice exhibited attenuated plasma TG excursion and accumulated lipid in the enterocytes. Electron microscopy studies revealed a lack of lipids in the lamina propria and intercellular space in Gpat3(-/-) mice. Gpat3(-/-) enterocytes displayed a compensatory increase in the synthesis of phospholipid and cholesteryl ester. When fed a Western-type diet, hepatic TG and cholesteryl ester accumulation was significantly higher in Gpat3(-/-) mice compared with the wild-type mice accompanied by elevated levels of alanine aminotransferase, a marker of liver injury. Dysregulation of bile acid metabolism was also evident in Gpat3-null mice. These studies identify GPAT3 as a novel enzyme involved in intestinal lipid metabolism. PMID:26644473

  17. A single amino acid change in Escherichia coli glycerol kinase abolishes glucose control of glycerol utilization in vivo.

    PubMed

    Pettigrew, D W; Liu, W Z; Holmes, C; Meadow, N D; Roseman, S

    1996-05-01

    Escherichia coli glycerol kinase (EC 2.7.1.30; ATP:glycerol 3-phosphotransferase) is a key element in glucose control of glycerol metabolism. Its catalytic activity is inhibited allosterically by the glycolytic intermediate, fructose 1,6-biphosphate, and by the phosphotransferase system phosphocarrier protein, IIIGlc (also known as IIAGlc). These inhibitors provide mechanisms by which glucose blocks glycerol utilization in vivo. We report here the cloning and sequencing of the glpK22 gene isolated from E. C. C. Lin strain 43, a strain that shows the loss of glucose control of glycerol utilization. DNA sequencing shows a single missense mutation that translates to the amino acid change Gly-304 to Ser (G-304-S) in glycerol kinase. The effects of this substitution on the functional and physical properties of the purified mutant enzyme were determined. Neither of the allosteric ligands inhibits it under conditions that produce strong inhibition of the wild-type enzyme, which is sufficient to explain the phenotype of strain 43. However, IIIGlc activates the mutant enzyme, which could not be predicted from the phenotype. In the wild-type enzyme, G-304 is located 1.3 nm from the active site and 2.5 nm from the IIIGlc binding site (M. Feese, D. W. Pettigrew, N. D. Meadow, S. Roseman, and S. J. Remington, Proc. Natl. Acad. Sci. USA 91:3544-3548, 1994). It is located in the same region as amino acid substitutions in the related protein DnaK which alter its catalytic and regulatory properties and which are postulated to interfere with a domain closure motion (A. S. Kamath-Loeb, C. Z. Lu, W.-C. Suh, M. A. Lonetto, and C. A. Gross, J. Biol. Chem. 270:30051-30059, 1995). The global effect of the G-304-S substitution on the conformation and catalytic and regulatory properties of glycerol kinase is consistent with a role for the domain closure motion in the molecular mechanism for glucose control of glycerol utilization. PMID:8631672

  18. Excess wing in glass-forming glycerol and LiCl-glycerol mixtures detected by neutron scattering

    SciTech Connect

    Gupta, S.; Arend, N.; Lunkenheimer, P.; Loidl, A.; Stingaciu, L.; Jalarvo, N.; Mamontov, E.; Ohl, M.

    2015-01-22

    The relaxational dynamics in glass-forming glycerol and glycerol mixed with LiCl is investigated using different neutron scattering techniques. The performed neutron spin echo experiments, which extend up to relatively long relaxation time scales of the order of 10 ns, should allow for the detection of contributions from the so-called excess wing. This phenomenon, whose microscopic origin is controversially discussed, arises in a variety of glass formers and, until now, was almost exclusively investigated by dielectric spectroscopy and light scattering. In conclusion, we show here that the relaxational process causing the excess wing can also be detected by neutron scattering, which directly couples to density fluctuations.

  19. Synthesis of isotopically labeled R- or S-[.sup.13C, .sup.2H] glycerols

    DOEpatents

    Martinez, Rodolfo A.; Unkefer, Clifford J.; Alvarez, Marc A.

    2008-01-22

    The present invention is directed to asymmetric chiral labeled glycerols including at least one chiral atom, from one to two .sup.13C atoms and from zero to four deuterium atoms bonded directly to a carbon atom, e.g., (2S) [1,2-.sup.13C.sub.2]glycerol and (2R) [1,2-.sup.13C.sub.2]glycerol, and to the use of such chiral glycerols in the preparation of labeled amino acids.

  20. Seasonal variability of branched glycerol dialkyl glycerol tetraethers (brGDGTs) in a temperate lake system

    NASA Astrophysics Data System (ADS)

    Loomis, Shannon E.; Russell, James M.; Heureux, Ana M.; D'Andrea, William J.; Sinninghe Damsté, Jaap S.

    2014-11-01

    Quantitative climate reconstructions are crucial for understanding the magnitude of and mechanisms behind natural and anthropogenic climate change, yet there are few proxies that can reliably reconstruct terrestrial temperature. Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are bacterial membrane lipids that are increasingly used to reconstruct paleotemperature from lake sediments, but despite their potential, we have a poor understanding of (1) autochthonous vs. allochthonous sources of brGDGTs in lakes and (2) the seasonality of and environmental controls on brGDGT production within lakes. To investigate these factors, we examined water column suspended particulate matter (SPM) and settling particles from a sediment trap collected on a biweekly to monthly basis over a period of three years at Lower King Pond, a small kettle lake in northern Vermont, USA. We also compared the concentration and fractional abundances of brGDGTs in SPM and settling particles with those of catchment soils, river sediments, and lake surface sediments to constrain the relative importance of brGDGTs derived from the landscape versus brGDGTs produced within the lake itself. We find significant differences in concentrations and fractional abundances of brGDGTs between soil and river sediment samples from the catchment and lake sediments, indicating a mostly autochthonous source for lacustrine brGDGTs. BrGDGT concentrations, fluxes, and fractional abundances in SPM vary over the annual cycle, indicating that brGDGTs are produced throughout the year and respond to changes within the water column. The total annual flux of brGDGTs settling through the water column is comparable to the brGDGT accumulation rates in surface sediments, indicating that in this lake brGDGTs are mostly produced within the water column, not in the sediment itself. While brGDGTs are produced in all seasons within the water column, the flux to the sediments is highest during periods of spring and fall

  1. Bronchial secretion concentrations of tobramycin.

    PubMed

    Alexander, M R; Schoell, J; Hicklin, G; Kasik, J E; Coleman, D

    1982-02-01

    The mean concentrations of tobramycin in bronchial secretions from patients with pneumonia were almost two times greater than secretions from patients free of lung infection. Mean tobramycin bronchial secretion to serum concentration ratios also were higher when obtained from infected lungs (0.66 versus 0.17) These data suggest that lung infection enhances the concentrations of tobramycin in bronchial secretions. PMID:7065524

  2. Synthesis, characterization and nanocomposite formation of poly(glycerol succinate-co-maleate) with cellulose nanowhiskers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A novel biodegradable polymer based on glycerol, succinic anhydride and maleic anhydride, poly(glycerol succinate-co-maleate), poly(GlySAMA), was synthesized by melt polycondensation and tested as a matrix for composites with cellulose nanowhiskers. This glycerol-based polymer is thermally stable as...

  3. Efficient utilization of crude glycerol as fermentation substrate in the synthesis of poly(3-hydroxybutyrate) biopolymers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One refined and 2 crude glycerol samples were utilized to produce poly(3-hydroxybutyrate) (PHB) by Pseudomonas oleovorans NRRL B-14682. Fermentation conditions were determined to efficiently utilize glycerol while maintaining PHB yields. A batch culture protocol including 1% glycerol and an aerati...

  4. Glycerol replacement corrects defective skin hydration, elasticity, and barrier function in aquaporin-3-deficient mice.

    PubMed

    Hara, Mariko; Verkman, A S

    2003-06-10

    Mice deficient in the epidermal water/glycerol transporter aquaporin-3 (AQP3) have reduced stratum corneum (SC) hydration and skin elasticity, and impaired barrier recovery after SC removal. SC glycerol content is reduced 3-fold in AQP3 null mice, whereas SC structure, protein/lipid composition, and ion/osmolyte content are not changed. We show here that glycerol replacement corrects each of the defects in AQP3 null mice. SC water content, measured by skin conductance and 3H2O accumulation, was 3-fold lower in AQP3 null vs. wild-type mice, but became similar after topical or systemic administration of glycerol in quantities that normalized SC glycerol content. SC water content was not corrected by glycerol-like osmolytes such as xylitol, erythritol, and propanediol. Orally administered glycerol fully corrected the reduced skin elasticity in AQP3 null mice as measured by the kinetics of skin displacement after suction, and the delayed barrier recovery as measured by transepidermal water loss after tape-stripping. Analysis of [14C]glycerol kinetics indicated reduced blood-to-SC transport of glycerol in AQP3 null mice, resulting in slowed lipid biosynthesis. These data provide functional evidence for a physiological role of glycerol transport by an aquaglyceroporin, and indicate that glycerol is a major determinant of SC water retention, and mechanical and biosynthetic functions. Our findings establish a scientific basis for the >200-yr-old empirical practice of including glycerol in cosmetic and medicinal skin formulations. PMID:12771381

  5. Production of arabitol from glycerol: strain screening and study of factors affecting production yield

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glycerol is a major byproduct from biodiesel production, and developing new uses for glycerol is imperative to overall economics and sustainability of the biodiesel industry. With the aim of producing xylitol and/or arabitol as the value-added products from glycerol, 214 yeast strains, many osmotole...

  6. The Effect of Glycerol Ingestion on Performance during Simulated Multisport Activity

    ERIC Educational Resources Information Center

    Knight, Christopher; Braakhuis, Andrea; Paton, Carl

    2010-01-01

    Glycerol-induced hyperhydration has been applied to endurance sport with limited success as a performance enhancement strategy. Glycerol has been used as a hyperhydrating agent, because it has been shown to be rapidly absorbed and osmotically active; therefore, the fluid intake with glycerol is distributed throughout the body. Hyperhydration with…

  7. Nitrogen-Corrected Apparent Metabolizable Energy Value of Crude Glycerol for Laying Hens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An experiment was conducted with laying hens to determine the AMEn value of crude glycerol, a co-product of biodiesel production. Crude glycerol (87% glycerol, 9% water, 0.03% methanol, 1.26% Na, and 3,625 kcal/kg gross energy) was obtained from a commercial biodiesel production facility (Ag Process...

  8. Thermal and mechanical properties of glycerol-based polymer films infused with plant cell wall polysaccharides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Poly(glutaric acid-co-glycerol) films were produced by first synthesizing polymer gels from uncatalyzed polyesterification of glutaric acid to glycerol in toluene. Residual amounts of starting materials in the gel matrices were determined by gas chromatography (GC) to contain 15 percent glycerol and...

  9. Toxicity of palmitoyl glycerol to mice: depression of thyroid function

    SciTech Connect

    Trumbo, P.R.; Meuten, D.J.; King, M.W.; Tove, S.B.

    1987-10-01

    Mice given propylthiouracil, a thyroid inhibitor, and fed a diet containing a nontoxic level of rac-1(3)-palmitoyl glycerol showed the hypothermia and mortality expected for a toxic dose, but did not show these signs when linoleate or oleate was added to the diet. Loss of radioiodine from the whole animal and thyroid gland was slower when mice were fed the toxic palmitoyl glycerol diet than when fed the same diet containing 4% safflower oil. However, mice fed the two diets did not differ in the extent of the incorporation of radioiodine, and essentially all was bound to protein in each case. Follicular thyroid cells from mice fed the potentially toxic diet that contained unsaturated fat were normal in appearance. Conversely, cells from mice fed the toxic diet were smaller and more densely stained, showing evidence of glycoprotein inside the cell. These findings show that the thyroid gland is affected by the palmitoyl glycerol diet. However, the thyroid is not the only organ affected, because giving either thyroxine or triiodothyronine had no effect on the toxicity of palmitoyl glycerol.

  10. Adaptation to physical training in rats orally supplemented with glycerol.

    PubMed

    Andrade, Eric Francelino; Lobato, Raquel Vieira; de Araújo, Ticiana Vasques; Orlando, Débora Ribeiro; Vicente da Costa, Diego; de Oliveira Silva, Víviam; Rogatto, Gustavo Puggina; Zangeronimo, Márcio Gilberto; Rosa, Priscila Vieira; Pereira, Luciano José

    2015-01-01

    We evaluated training adaptation and physical performance parameters in rats orally supplemented with glycerol, glucose, or saline, and submitted to moderate aerobic exercise. Thirty male rats were trained for 6 weeks and administered the supplements during the last 4 weeks of the experiment. Animals were distributed in a completely randomized factorial 2 × 3 design (with or without exercise and 3 substrates). Data were subjected to analysis of variance (ANOVA) and means were compared using the Student-Newmann-Keuls test at 5%. Among the trained animals, none of the substances caused differences in the percentages of protein, fat, or water content in the carcass. Compared with the sedentary animals, the trained animals supplemented with saline and glucose showed a higher protein percentage in the carcass. The relative mass of the heart and adrenal glands was higher in the trained animals. Glycerol improved the protein content in non-trained animals and increased the relative adrenal mass in both groups. Glycerol reduced the variation in levels of lactate and aspartate aminotransferase (AST) during the last exercise session. There was no difference between groups regarding the relative mass of the thymus and gastrocnemius or with the diameter of muscle fibers or the neutrophil-lymphocyte ratio. Supplementation with glycerol was efficient at attenuating variation in AST and lactate levels during exercise. PMID:25474597

  11. Crude glycerol combustion: particulate, acrolein, and other volatile organic emissions

    EPA Science Inventory

    Crude glycerol is an abundant by-product of biodiesel production. As volumes of this potential waste grow, there is increasing interest in developing new value added uses. One possible use, as a boiler fuel for process heating, offers added advantages of energy integration and ...

  12. Conversion of Phosphatidylcholine to PPosphatidylglycerol with phospholipase D and Glycerol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphatidylglycerol (PtdGly) is a relatively rare phospholipid that is useful in lubricant applications. Recently glycerol has become available in large quantities as a byproduct of biodiesel production, allowing for the economical synthesis of PtdGly. The conversion of readily available phosphat...

  13. 21 CFR 172.735 - Glycerol ester of rosin.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Glycerol ester of rosin. 172.735 Section 172.735 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Other Specific Usage Additives §...

  14. 21 CFR 172.735 - Glycerol ester of rosin.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Glycerol ester of rosin. 172.735 Section 172.735 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR...

  15. 21 CFR 172.735 - Glycerol ester of rosin.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Glycerol ester of rosin. 172.735 Section 172.735 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Other Specific Usage Additives §...

  16. Biocomposites Prepared from Fiber Processing Wastes and Glycerol Polyesters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biocomposites were prepared by the addition of flax fiber processing waste to glycerol and adipic acid mixtures. The processing waste consisted of fiber, cuticle, and shive fragments generated during the commercial cleaning of retted flax bast fibers. These waste materials were added at 1, 3, or 5 w...

  17. Dark fermentative bioconversion of glycerol to hydrogen by Bacillus thuringiensis.

    PubMed

    Kumar, Prasun; Sharma, Rishi; Ray, Subhasree; Mehariya, Sanjeet; Patel, Sanjay K S; Lee, Jung-Kul; Kalia, Vipin C

    2015-04-01

    Biodiesel manufacturing units discharge effluents rich in glycerol. The need is to convert crude glycerol (CG) into useful products such as hydrogen (H2). Under batch culture, Bacillusthuringiensis EGU45 adapted on pure glycerol (PG, 2% v/v) resulted in an H2 yield of 0.646 mol/mol glycerol consumed on minimal media (250 mL) supplemented with 1% ammonium nitrate at 37°C over 4 days. Here, H2 constituted 67% of the total biogas. Under continuous culture, at 2 days of hydraulic retention time, B. thuringiensis immobilized on ligno-cellulosic materials (banana leaves - BL, 10% v/v) resulted in a H2 yield of 0.386 mol/mol PG consumed. On CG, the maximal H2 yield of 0.393 mol/mol feed consumed was recorded. In brief, B. thuringiensis could transform CG, on limited resources - minimal medium with sodium nitrate, by immobilizing them on cheap and easily available biowaste, which makes it a suitable candidate for H2 production on a large scale. PMID:25686722

  18. Genetically engineered rhamnolipid-producing organism for glycerol utilization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhamnolipid (RL) is a microbial glycolipid currently developed for industrial use as a biobased surfactant. It also possesses antimicrobial activity that is attractive for applications in sanitizing washes. Glycerol byproduct stream from biodiesel production is a promising low-cost substrate for m...

  19. Optimization process of tribenzoine production as a glycerol derived product

    NASA Astrophysics Data System (ADS)

    Widayat, Abdurrakhman, Rifianto, Y.; Abdullah, Hadiyanto, Samsudin, Asep M.; Annisa, A. N.

    2015-12-01

    Tribenzoin is a derived product from glycerol that can produce from glycerol conversion via esterification process. The product can be used in the food industry, cosmetics industry, polymer industry and also can be used to improve the properties of adhesive materials and water resistance in the ink printer.In the other hand, it advantages is environmentally friendly andrenewable because it is not derived from petroleum. This paper discusses the effect of temperature and catalyst concentration for tribenzoin production. For the responses, yield and product composition were observed. Results showed that the highest yield achieved at optimal variable data processed using Central Composite Design (CCD) which is 63.64 temperature (°C), mole ratio of benzoic acidto glycerol is 3.644:1, and catalyst concentration 6.25% (wt% glycerol). Yield products produced 58.71%. FTIR analysis results showed that the samples contained the results of IR spectra wavelength 1761 cm-1 in the fingerprint region and 3165 cm-1 frequency region group. The existence of these two adjustments that fixed in the area is strong evidence that the compound is tribenzoin.

  20. Genetic determinants for enhanced glycerol growth of Saccharomyces cerevisiae.

    PubMed

    Swinnen, Steve; Ho, Ping-Wei; Klein, Mathias; Nevoigt, Elke

    2016-07-01

    The yeast Saccharomyces cerevisiae generally shows a low natural capability to utilize glycerol as the sole source of carbon, particularly when synthetic medium is used and complex supplements are omitted. Nevertheless, wild type isolates have been identified that show a moderate growth under these conditions. In the current study we made use of intraspecies diversity to identify targets suitable for reverse metabolic engineering of the non-growing laboratory strain CEN.PK113-1A. A genome-wide genetic mapping experiment using pooled-segregant whole-genome sequence analysis was conducted, and one major and several minor genetic loci were identified responsible for the superior glycerol growth phenotype of the previously selected S. cerevisiae strain CBS 6412-13A. Downscaling of the major locus by fine-mapping and reciprocal hemizygosity analysis allowed the parallel identification of two superior alleles (UBR2CBS 6412-13A and SSK1CBS 6412-13A). These alleles together with the previously identified GUT1CBS 6412-13A allele were used to replace the corresponding alleles in the strain CEN.PK113-1A. In this way, glycerol growth could be established reaching a maximum specific growth rate of 0.08h(-1). Further improvement to a maximum specific growth rate of 0.11h(-1) could be achieved by heterologous expression of the glycerol facilitator FPS1 from Cyberlindnera jadinii. PMID:26971668

  1. Performance and carcass characteristics of growing pigs fed crude glycerol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Performance and carcass characteristics of growing pigs fed crude glycerol, a co-product of biodiesel production, were determined in a 138-d feeding trial conducted at the Iowa State University Swine Nutrition Research Farm, Ames, IA. Pigs were weaned at 21d of age and were fed a commercial starter-...

  2. Apparent digestible energy value of crude glycerol fed to pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The apparent digestible energy of crude glycerol, a co-product of biodiesel production, was determined in two studies conducted at the Iowa State University Swine Nutrition Research Farm, Ames, IA. In the first study, 24 barrows with an average body weight of 11.0 kg were fed 376 g/d of a basal corn...

  3. Synthesis of High-Molecular-Weight Multifunctional Glycerol Polyhydroxyurethanes PHUs.

    PubMed

    Nohra, Bassam; Candy, Laure; Blanco, Jean-François; Raoul, Yann; Mouloungui, Zéphirin

    2016-01-01

    Glycerol carbonate acrylate is a 5-membered cyclic carbonate synthesized from glycerol that is used as a chemical coupling agent and has proven highly suitable for use in the synthesis of multifunctional polyhydroxyurethanes (PHUs). The multifunctionality of the structure of PHUs is determined by the density of the carbon-amine groups generated by the Aza-Michael reaction and that of the urethane groups and adjacent primary and secondary hydroxyl groups generated by aminolysis. Glycerol carbonate acrylate is polymerized with polyfunctional mono-, di-, tri, and tetra-amines, by type-AB polyaddition, either in bulk or in solution, through stepwise or one-pot reaction strategies in the absence of added catalysts. These approaches result in the generation of linear, interchain, and crosslinked structures, through the polyaddition of linear and branched amines to the ethylene and cyclic carbonate sites of glycerol carbonate acrylate. The resulting collection of organic molecules gives rise to polyethylene amino ester PHUs with a high molar mass, exceeding 20,000 g·mol(-1), with uniform dispersity. PMID:27626401

  4. Glycerolized Reticular Dermis as a New Human Acellular Dermal Matrix: An Exploratory Study.

    PubMed

    Ferrando, Pietro Maria; Balmativola, Davide; Cambieri, Irene; Scalzo, Maria Stella; Bergallo, Massimiliano; Annaratone, Laura; Casarin, Stefania; Fumagalli, Mara; Stella, Maurizio; Sapino, Anna; Castagnoli, Carlotta

    2016-01-01

    Human Acellular Dermal Matrices (HADM) are employed in various reconstructive surgery procedures as scaffolds for autologous tissue regeneration. The aim of this project was to develop a new type of HADM for clinical use, composed of glycerolized reticular dermis decellularized through incubation and tilting in Dulbecco's Modified Eagle's Medium (DMEM). This manufacturing method was compared with a decellularization procedure already described in the literature, based on the use of sodium hydroxide (NaOH), on samples from 28 donors. Cell viability was assessed using an MTT assay and microbiological monitoring was performed on all samples processed after each step. Two surgeons evaluated the biomechanical characteristics of grafts of increasing thickness. The effects of the different decellularization protocols were assessed by means of histological examination and immunohistochemistry, and residual DNA after decellularization was quantified using a real-time TaqMan MGB probe. Finally, we compared the results of DMEM based decellularization protocol on reticular dermis derived samples with the results of the same protocol applied on papillary dermis derived grafts. Our experimental results indicated that the use of glycerolized reticular dermis after 5 weeks of treatment with DMEM results in an HADM with good handling and biocompatibility properties. PMID:26918526

  5. Glycerolized Reticular Dermis as a New Human Acellular Dermal Matrix: An Exploratory Study

    PubMed Central

    Ferrando, Pietro Maria; Balmativola, Davide; Cambieri, Irene; Scalzo, Maria Stella; Bergallo, Massimiliano; Annaratone, Laura; Casarin, Stefania; Fumagalli, Mara; Stella, Maurizio; Sapino, Anna; Castagnoli, Carlotta

    2016-01-01

    Human Acellular Dermal Matrices (HADM) are employed in various reconstructive surgery procedures as scaffolds for autologous tissue regeneration. The aim of this project was to develop a new type of HADM for clinical use, composed of glycerolized reticular dermis decellularized through incubation and tilting in Dulbecco’s Modified Eagle’s Medium (DMEM). This manufacturing method was compared with a decellularization procedure already described in the literature, based on the use of sodium hydroxide (NaOH), on samples from 28 donors. Cell viability was assessed using an MTT assay and microbiological monitoring was performed on all samples processed after each step. Two surgeons evaluated the biomechanical characteristics of grafts of increasing thickness. The effects of the different decellularization protocols were assessed by means of histological examination and immunohistochemistry, and residual DNA after decellularization was quantified using a real-time TaqMan MGB probe. Finally, we compared the results of DMEM based decellularization protocol on reticular dermis derived samples with the results of the same protocol applied on papillary dermis derived grafts. Our experimental results indicated that the use of glycerolized reticular dermis after 5 weeks of treatment with DMEM results in an HADM with good handling and biocompatibility properties. PMID:26918526

  6. Quantification of the ratio of positional isomer dilinoleoyl-oleoyl glycerols in vegetable oils.

    PubMed

    Jakab, A; Jablonkai, I; Forgács, E

    2003-01-01

    The distribution of fatty acids in a triacylglycerol is of great importance from nutritional, biochemical, quality and technological points of view. The ratio of triacylglycerol positional isomers containing two linoleic acid (18:2) and one oleic acid (18:1) moieties--namely, 1(3),2-dilinoleoyl-3(1)-oleoyl glycerol (LLO) and 1,3-dilinoleoyl-2-oleoyl glycerol (LOL)--were quantified in grape seed, olive, pumpkin seed, soybean, sunflower and wheat germ oils by high-performance liquid chromatography/atmospheric pressure chemical ionization mass spectrometry (HPLC/APCI-MS) in selected ion monitoring (SIM) mode. Relative LOL contents (LOL/(LLO+LOL)) of the oils were calculated from the mass abundances of the [LL]+ and [LO]+ diacylglycerol fragment ions ([M+H-RCOOH]+) using a calibration curve. The calibration curve of the relative diacylglycerol mass abundances was measured in SIM mode. The relative LOL contents were found to be relatively consistent for each oil variety. The relative LOL content in grape seed, sunflower, pumpkin seed, soybean and wheat germ oils accounted for 44.2 +/- 2.6, 26.8 +/- 3.2, 16.7 +/- 4.6, 15.9 +/- 2.9 and 13.9 +/- 4.3%, respectively. Only olive oils contained practically 100% of the LLO isomer. These results indicate that the unsaturated fatty acids such as linoleic and oleic acids have 'non-random' distribution patterns in various oils. PMID:14558129

  7. Increasing the penetration depth for ultrafast laser tissue ablation using glycerol based optical clearing

    NASA Astrophysics Data System (ADS)

    Gabay, Ilan; Subramanian, Kaushik G.; Martin, Chris; Yildirim, Murat; Tuchin, Valery V.; Ben-Yakar, Adela

    2016-03-01

    Background: Deep tissue ablation is the next challenge in ultrafast laser microsurgery. By focusing ultrafast pulses below the tissue surface one can create an ablation void confined to the focal volume. However, as the ablation depth increases in a scattering tissue, increase in the required power can trigger undesired nonlinear phenomena out of focus that restricts our ability to ablate beyond a maximum ablation depth of few scattering lengths. Optical clearing (OC) might reduce the intensity and increase the maximal ablation depth by lowering the refractive index mismatch, and therefore reducing scattering. Some efforts to ablate deeper showed out of focus damage, while others used brutal mechanical methods for clearing. Our clinical goal is to create voids in the scarred vocal folds and inject a biomaterial to bring back the tissue elasticity and restore phonation. Materials and methods: Fresh porcine vocal folds were excised and applied a biocompatible OC agent (75% glycerol). Collimated transmittance was monitored. The tissue was optically cleared and put under the microscope for ablation threshold measurements at different depths. Results: The time after which the tissue was optically cleared was roughly two hours. Fitting the threshold measurements to an exponential decay graph indicated that the scattering length of the tissue increased to 83+/-16 μm, which is more than doubling the known scattering length for normal tissue. Conclusion: Optical clearing with Glycerol increases the tissue scattering length and therefore reduces the energy for ablation and increases the maximal ablation depth. This technique can potentially improve clinical microsurgery.

  8. Distribution of metabolic fluxes towards glycerol phosphate and L-lactate from fructose 1,6-biphosphate in vitro: effect of glycerol phosphate dehydrogenase.

    PubMed

    Riol-Cimas, J M; Meléndez-Hevia, E

    1986-01-01

    A metabolic system in vitro, which converts fructose 1,6-biphosphate into the two alternative products, lactate and glycerol phosphate, was designed to study the distribution of metabolic fluxes and, specifically, the control of glycerol phosphate production rate in rat muscle extract. Experiments were carried out at several protein concentrations by dilution of rat muscle extract, showing non-linear behaviours of flux versus protein concentration. These were hyperbolic for glycerol phosphate and logarithmic for L-lactate. The influence of the flux towards any alternate product on the rate giving the other was studied by stimulation of each. Results obtained show that in this system, flux towards glycerol phosphate is not affected by lactate production and the same occurs for the contrary case. Glycerol phosphate dehydrogenase seems to be the only enzyme in this system whose activity controls the flux towards glycerol phosphate. PMID:3758466

  9. Biochemical Methods to Analyze Wnt Protein Secretion.

    PubMed

    Glaeser, Kathrin; Boutros, Michael; Gross, Julia Christina

    2016-01-01

    Wnt proteins act as potent morphogens in various aspects of embryonic development and adult tissue homeostasis. However, in addition to its physiological importance, aberrant Wnt signaling has been linked to the onset and progression of different types of cancer. On the cellular level, the secretion of Wnt proteins involves trafficking of lipid-modified Wnts from the endoplasmic reticulum (ER) to Golgi and further compartments via the Wnt cargo receptor evenness interrupted. Others and we have recently shown that Wnt proteins are secreted on extracellular vesicles (EVs) such as microvesicles and exosomes. Although more details about specific regulation of Wnt secretion steps are emerging, it remains largely unknown how Wnt proteins are channeled into different release pathways such as lipoprotein particles, EVs and cytonemes. Here, we describe protocols to purify and quantify Wnts from the supernatant of cells by either assessing total Wnt proteins in the supernatant or monitoring Wnt proteins on EVs. Purified Wnts from the supernatant as well as total cellular protein content can be investigated by immunoblotting. Additionally, the relative activity of canonical Wnts in the supernatant can be assessed by a dual-luciferase Wnt reporter assay. Quantifying the amount of secreted Wnt proteins and their activity in the supernatant of cells allows the investigation of intracellular trafficking events that regulate Wnt secretion and the role of extracellular modulators of Wnt spreading. PMID:27590148

  10. Rainbow smelt: the unusual case of cryoprotection by sustained glycerol production in an aquatic animal.

    PubMed

    Driedzic, William R

    2015-07-01

    Rainbow smelt flourish at -1.8 °C, the freezing point of sea water. An antifreeze protein contributes to freeze point depression but, more importantly, cryoprotection is due to an elevation in osmotic pressure, by the accumulation of glycerol. The lower the water temperature, the higher the plasma glycerol with levels recorded as high as 400 mmol l(-1). Glycerol freely diffuses out in direct relation to the glycerol concentration and fish may lose as much as 15% of their glycerol reserve per day. Glycerol levels decrease from a maximum in February/March while water temperature is still sub-zero. The decrease in glycerol may respond to a photoperiod signal as opposed to initiation which is triggered by low temperature. The initial increase in glycerol level is supported by liver glycogen but high sustained glycerol level is dependent upon dietary carbohydrate and protein. The metabolic pathways leading to glycerol involve flux from glycogen/glucose to the level of dihydroxyacetone phosphate (DHAP) via the initial part of glycolysis and from amino acids via a truncated gluconeogenesis again to the level of DHAP. DHAP in turn is converted to glycerol 3-phosphate (G3P) and then directly to glycerol. The key to directing DHAP to G3P is a highly active glycerol 3-P dehydrogenase. G3P is converted directly to glycerol via G3P phosphatase, the rate-limiting step in the process. The transition to glycerol production is associated with increased activities of enzymes at key loci in the top part of glycogenolysis/glycolysis. Curtailment of the final section of glycolysis may reside at the level of pyruvate oxidation with an inactivation of pyruvate dehydrogenase (PDH) driven by increased levels of PDH kinase. Enzymes associated with amino acid trafficking are elevated as is the pivotal enzyme phosphoenolpyruvate carboxykinase. PMID:25921795

  11. Fueling type III secretion

    PubMed Central

    Lee, Pei-Chung

    2015-01-01

    Type III secretion systems are complex nanomachines that export proteins from the bacterial cytoplasm across the cell envelope in a single step. They are at the core of the machinery used to assemble the bacterial flagellum, and the needle complex many Gram-negative pathogens use to inject effector proteins into host cells and cause disease. Several models have been put forward to explain how this export is energized, and the mechanism has been the subject of considerable debate. Here we present an overview of these models and discuss their relative merits. Recent evidence suggests that the proton motive force is the primary energy source for type III secretion, although contribution from refolding of secreted proteins has not been ruled out. The mechanism, by which the proton motive force is converted to protein export, remains enigmatic. PMID:25701111

  12. Ovarian tumors secreting insulin.

    PubMed

    Battocchio, Marialberta; Zatelli, Maria Chiara; Chiarelli, Silvia; Trento, Mariangela; Ambrosio, Maria Rosaria; Pasquali, Claudio; De Carlo, Eugenio; Dassie, Francesca; Mioni, Roberto; Rebellato, Andrea; Fallo, Francesco; Degli Uberti, Ettore; Martini, Chiara; Vettor, Roberto; Maffei, Pietro

    2015-08-01

    Combined ovarian germ cell and neuroendocrine tumors are rare. Only few cases of hyperinsulinism due to ovarian ectopic secretion have been hypothesized in the literature. An ovarian tumor was diagnosed in a 76-year-old woman, referred to our department for recurrent hypoglycemia with hyperinsulinism. In vivo tests, in particular fasting test, rapid calcium infusion test, and Octreotide test were performed. Ectopic hyperinsulinemic hypoglycemia was demonstrated in vivo and hypoglycemia disappeared after hysteroadnexectomy. Histological exam revealed an ovarian germ cell tumor with neuroendocrine and Yolk sac differentiation, while immunostaining showed insulin positivity in neuroendocrine cells. A cell culture was obtained by tumoral cells, testing Everolimus, and Pasireotide. Insulin was detected in cell culture medium and Everolimus and Pasireotide demonstrated their potentiality in reducing insulin secretion, more than controlling cell viability. Nine cases of hyperinsulinism due to ovarian ectopic secretion reported in literature have been reviewed. These data confirm the ovarian tissue potentiality to induce hyperinsulinemic hypoglycemic syndrome after neoplastic transformation. PMID:25896552

  13. The Glycerol-Dependent Metabolic Persistence of Pseudomonas putida KT2440 Reflects the Regulatory Logic of the GlpR Repressor

    PubMed Central

    Nikel, Pablo I.; Romero-Campero, Francisco J.; Zeidman, Joshua A.; Goñi-Moreno, Ángel

    2015-01-01

    ABSTRACT The growth of the soil bacterium Pseudomonas putida KT2440 on glycerol as the sole carbon source is characterized by a prolonged lag phase, not observed with other carbon substrates. We examined the bacterial growth in glycerol cultures while monitoring the metabolic activity of individual cells. Fluorescence microscopy and flow cytometry, as well as the analysis of the temporal start of growth in single-cell cultures, revealed that adoption of a glycerol-metabolizing regime was not the result of a gradual change in the whole population but rather reflected a time-dependent bimodal switch between metabolically inactive (i.e., nongrowing) and fully active (i.e., growing) bacteria. A transcriptional Φ(glpD-gfp) fusion (a proxy of the glycerol-3-phosphate [G3P] dehydrogenase activity) linked the macroscopic phenotype to the expression of the glp genes. Either deleting glpR (encoding the G3P-responsive transcriptional repressor that controls the expression of the glpFKRD gene cluster) or altering G3P formation (by overexpressing glpK, encoding glycerol kinase) abolished the bimodal glpD expression. These manipulations eliminated the stochastic growth start by shortening the otherwise long lag phase. Provision of glpR in trans restored the phenotypes lost in the ΔglpR mutant. The prolonged nongrowth regime of P. putida on glycerol could thus be traced to the regulatory device controlling the transcription of the glp genes. Since the physiological agonist of GlpR is G3P, the arrangement of metabolic and regulatory components at this checkpoint merges a positive feedback loop with a nonlinear transcriptional response, a layout fostering the observed time-dependent shift between two alternative physiological states. PMID:25827416

  14. In vivo quantification of propylene glycol, glucose and glycerol diffusion in human skin with optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Guo, X.; Guo, Z. Y.; Wei, H. J.; Yang, H. Q.; He, Y. H.; Xie, S. S.; Wu, G. Y.; Zhong, H. Q.; Li, L. Q.; Zhao, Q. L.

    2010-09-01

    The purpose of study is to quantify and compare diffusion of propylene glycol, glucose, glycerol in the human skin in vivo noninvasively. Optical coherence tomography (OCT) was utilized in the functional imaging of optical cleaning agents for monitoring and quantifying the permeability coefficients (PCs) of them. Our experiments showed that the permeability coefficient of 40% propylene glycol from different subjects was averaged and found to be (2.52 ± 0.02) × 10-6 cm/s, the permeability coefficient of 40% glucose was (1.94 ± 0.05) × 10-6 cm/s, and the permeability coefficient of 40% glycerol was (1.82 ± 0.04) × 10-6 cm/s. The results indicated that the diffusion of propylene glycol solutions was faster than that of glucose solution, and the diffusion of glucose solutions was faster than that of glycerol solutions. The dependence of the permeability on the different hyperosmotic analytes could potentially be used in various basic science and clinical fields, such as optical clearing of tissues and cells as well as in clinical pharmacology.

  15. Multiparty quantum secret sharing

    SciTech Connect

    Zhang Zhanjun; Li Yong; Man Zhongxiao

    2005-04-01

    Based on a quantum secure direct communication (QSDC) protocol [Phys. Rev. A 69 052319 (2004)], we propose a (n,n)-threshold scheme of multiparty quantum secret sharing of classical messages (QSSCM) using only single photons. We take advantage of this multiparty QSSCM scheme to establish a scheme of multiparty secret sharing of quantum information (SSQI), in which only all quantum information receivers collaborate can the original qubit be reconstructed. A general idea is also proposed for constructing multiparty SSQI schemes from any QSSCM scheme.

  16. Identification and Expression of the Genes Encoding a Reactivating Factor for Adenosylcobalamin-Dependent Glycerol Dehydratase

    PubMed Central

    Tobimatsu, Takamasa; Kajiura, Hideki; Yunoki, Michio; Azuma, Muneaki; Toraya, Tetsuo

    1999-01-01

    Adenosylcobalamin-dependent glycerol dehydratase undergoes inactivation by glycerol, the physiological substrate, during catalysis. In permeabilized cells of Klebsiella pneumoniae, the inactivated enzyme is reactivated in the presence of ATP, Mg2+, and adenosylcobalamin. We identified the two open reading frames as the genes for a reactivating factor for glycerol dehydratase and designated them gdrA and gdrB. The reactivation of the inactivated glycerol dehydratase by the gene products was confirmed in permeabilized recombinant Escherichia coli cells coexpressing GdrA and GdrB proteins with glycerol dehydratase. PMID:10383983

  17. Sodium-induced hyperhydration decreases urine output and improves fluid balance compared with glycerol- and water-induced hyperhydration.

    PubMed

    Savoie, Félix A; Dion, Tommy; Asselin, Audrey; Goulet, Eric D B

    2015-01-01

    Before 2010, which is the year the World Anti-Doping Agency banned its use, glycerol was commonly used by athletes for hyperhydration purposes. Through its effect on osmoreceptors, we believe that sodium could prove a viable alternative to glycerol as a hyperhydrating agent. Therefore, this study compared the effects of sodium-induced hyperhydration (SIH), glycerol-induced hyperhydration (GIH) and water-induced hyperhydration (WIH) on fluid balance responses. Using a randomized, double-blind and counterbalanced protocol, 17 men (21 ± 3 years, 64 ± 6 kg fat-free mass (FFM)) underwent three 3-h hyperhydration protocols during which they ingested, over the first 60-min period, 30 mL/kg FFM of water with (i) an artificial sweetener (WIH); (ii) an artificial sweetener + 7.45 g/L of table salt (SIH); or (iii) an artificial sweetener + 1.4 g glycerol/kg FFM (GIH). Changes in body weight (BW), urine production, fluid retention, hemoglobin, hematocrit, plasma volume, and perceptual variables were monitored throughout the 3-h trials. After 3 h, SIH was associated with significantly (p < 0.05) lower hemoglobin, hematocrit (SIH: 43.1% ± 2.8%; GIH: 44.9% ± 2.4%), and urine production, as well as greater BW, fluid retention (SIH: 1144 ± 294 mL; GIH: 795 ± 337 mL), and plasma volume (SIH: 11.9% ± 12.0%; GIH: 4.0% ± 6.0%) gains, compared with GIH and WIH. No significant differences in heart rate or abdominal discomfort were observed between treatments. In conclusion, our results indicate that SIH is a superior hyperhydrating technique than, and proves to be a worthwhile alternative to, GIH. PMID:25494972

  18. Expression and functional studies of genes involved in transport and metabolism of glycerol in Pachysolen tannophilus

    PubMed Central

    2013-01-01

    Background Pachysolen tannophilus is a non-conventional yeast, which can metabolize many of the carbon sources found in low cost feedstocks including glycerol and xylose. The xylose utilisation pathways have been extensively studied in this organism. However, the mechanism behind glycerol metabolism is poorly understood. Using the recently published genome sequence of P. tannophilus CBS4044, we searched for genes with functions in glycerol transport and metabolism by performing a BLAST search using the sequences of the relevant genes from Saccharomyces cerevisiae as queries. Results Quantitative real-time PCR was performed to unveil the expression patterns of these genes during growth of P. tannophilus on glycerol and glucose as sole carbon sources. The genes predicted to be involved in glycerol transport in P. tannophilus were expressed in S. cerevisiae to validate their function. The S. cerevisiae strains transformed with heterologous genes showed improved growth and glycerol consumption rates with glycerol as the sole carbon source. Conclusions P. tannophilus has characteristics relevant for a microbial cell factory to be applied in a biorefinery setting, i.e. its ability to utilise the carbon sources such as xylose and glycerol. However, the strain is not currently amenable to genetic modification and transformation. Heterologous expression of the glycerol transporters from P. tannophilus, which has a relatively high growth rate on glycerol, could be used as an approach for improving the efficiency of glycerol assimilation in other well characterized and applied cell factories such as S. cerevisiae. PMID:23514356

  19. The Role of Glycerol in the Osmotic Regulation of the Halophilic Alga Dunaliella parva

    PubMed Central

    Ben-Amotz, Ami; Avron, Mordhay

    1973-01-01

    Dunaliella parva, a green halophilic alga, was found to accumulate very large amounts of intracellular glycerol. Through measurements of the intracellular volume the internal concentration of glycerol was calculated and found to be around 2.1 m in cells cultured in 1.5 m NaCl. When the extracellular salt concentration of an algal suspension was increased or decreased, the intracellular glycerol varied accordingly, reaching its new osmotic equilibrium after about 90 minutes. Since no leakage of intracellular glycerol was observed above 0.6 m NaCl, these alterations in glycerol content are interpreted as due to metabolic formation and degradation of intracellular glycerol. The above results indicate the existence of a new type of algal osmoregulation, in which the osmotic balance depends on the synthesis or degradation of intracellular glycerol in response to the external salt concentration. PMID:16658431

  20. Effect of crude glycerol impurities on lipid preparation by Rhodosporidium toruloides yeast 32489.

    PubMed

    Gao, Zhen; Ma, Yingqun; Wang, Qunhui; Zhang, Min; Wang, Juan; Liu, Yu

    2016-10-01

    Crude glycerol (byproduct of biodiesel preparation) was utilised as the carbon source to produce lipid using oleaginous yeast Rhodosporidium toruloides 32489. Under the same conditions, lipid production with crude glycerol was higher than those produced with glucose and pure glycerol. The effects of 4 main impurities in crude glycerol (methyl oleate, sodium oleate, NaCl and methanol) on lipid production were investigated. Compared with utilising pure glycerol, addition of methyl oleate, sodium oleate, and NaCl impurities increased lipid production by 47.0%, 68.0% and 64.0%, respectively, while methanol decreased lipid production by 17.7%. However, when methanol was mixed with other impurities, its inhibition effect was alleviated due to the promoting effect of other impurities. Hence, crude glycerol could be used as a renewable and low-cost carbon source to replace pure glucose or glycerol for lipid preparation. PMID:27387413

  1. Dynamics of solvent and rotational relaxation of glycerol in the nanocavity of reverse micelles.

    PubMed

    Chakraborty, Anjan; Seth, Debabrata; Setua, Palash; Sarkar, Nilmoni

    2006-03-23

    The dynamics of solvent and rotational relaxation of Coumarin 480 and Coumarin 490 in glycerol containing bis-2-ethyl hexyl sulfosuccinate sodium salt (AOT) reverse micelles have been investigated with steady-state and time-resolved fluorescence spectroscopy. We observed slower solvent relaxation of glycerol confined in the nanocavity of AOT reverse micelles compared to that in pure glycerol. However, the slowing down in the solvation time on going from neat glycerol to glycerol confined reverse micelles is not comparable to that on going from pure water or acetonitrile to water or acetonitrile confined AOT reverse micellar aggregates. While solvent relaxation times were found to decrease with increasing glycerol content in the reverse micellar pool, rotational relaxation times were found to increase with increase in glycerol content. PMID:16539469

  2. Glycerol dialkyl glycerol tetraethers preserved in stalagmites: a new continental palaeothermometer

    NASA Astrophysics Data System (ADS)

    Blyth, A. J.; Schouten, S.

    2010-12-01

    The ability to recover reliable temperature records is central to palaeoclimatic research, informing our understanding of the past and our models of the future. However, there is a need for new quantitative terrestrial temperature proxies. Here we present a novel palaeothermometer, combining molecular temperature proxies with the strong dating control and established environmental records provided by stalagmites. The results show good correlations between known and calculated temperatures, suggesting that the approach has considerable potential as a climatic proxy. Glycerol dialkyl glycerol tetraethers (GDGTs) are microbial membrane lipids, which vary in structure with temperature and pH [1]. In the terrestrial realm, the focus is on bacterially derived GDGTs, which have been used to measure terrestrial organic matter input to aquatic deposits via the BIT index [2], and developed into a temperature related index (MBT/CBT) in soils and near-shore marine sediments (MBT/CBT), based upon the degree of branching and cyclicisation of the carbon skeleton [3]. Stalagmites form an ideal archive for terrestrial climate records, as they are stable, can be easily dated, and contain a number of environmental proxies (stable isotopes, trace elements, organic matter etc). Attempts have been made to develop inorganic temperature proxies in stalagmites, most recently using isotopic analysis of fluid inclusions. However, the use of organic temperature proxies in this context is largely unstudied. Thirty-eight stalagmite or stalactite samples from twenty-one sites around the world were analysed for their GDGT content. Calcite samples were cleaned and decalcified with HCl, and lipids extracted into dichloromethane via liquid-liquid extraction. Each extract was then prepared and analysed via HPLC-MS following Weijers et al. [3]. The results show low but usable levels of GDGTs in all but one sample. Peak size measurements were made for all recognised compounds associated with BIT and

  3. Glycerol carbonate as green solvent for pretreatment of sugarcane bagasse

    PubMed Central

    2013-01-01

    Background Pretreatment of lignocellulosic biomass is a prerequisite for effective saccharification to produce fermentable sugars. In this study, “green” solvent systems based on acidified mixtures of glycerol carbonate (GC) and glycerol were used to treat sugarcane bagasse and the roles of each solvent in deconstructing biomass were determined. Results Pretreatment of sugarcane bagasse at 90°C for only 30 min with acidified GC produced a solid residue having a glucan digestibility of 90% and a glucose yield of 80%, which were significantly higher than a glucan digestibility of 16% and a glucose yield of 15% obtained for bagasse pretreated with acidified ethylene carbonate (EC). Biomass compositional analyses showed that GC pretreatment removed more lignin than EC pretreatment (84% vs 54%). Scanning electron microscopy (SEM) showed that fluffy and size-reduced fibres were produced from GC pretreatment whereas EC pretreatment produced compact particles of reduced size. The maximal glucan digestibility and glucose yield of GC/glycerol systems were about 7% lower than those of EC/ethylene glycol (EG) systems. Replacing up to 50 wt% of GC with glycerol did not negatively affect glucan digestibility and glucose yield. The results from pretreatment of microcrystalline cellulose (MCC) showed that (1) pretreatment with acidified alkylene glycol (AG) alone increased enzymatic digestibility compared to pretreatments with acidified alkylene carbonate (AC) alone and acidified mixtures of AC and AG, (2) pretreatment with acidified GC alone slightly increased, but with acidified EC alone significantly decreased, enzymatic digestibility compared to untreated MCC, and (3) there was a good positive linear correlation of enzymatic digestibility of treated and untreated MCC samples with congo red (CR) adsorption capacity. Conclusions Acidified GC alone was a more effective solvent for pretreatment of sugarcane bagasse than acidified EC alone. The higher glucose yield obtained

  4. Bi-functional biobased packing of the cassava starch, glycerol, licuri nanocellulose and red propolis.

    PubMed

    Costa, Samantha Serra; Druzian, Janice Izabel; Machado, Bruna Aparecida Souza; de Souza, Carolina Oliveira; Guimarães, Alaíse Gil

    2014-01-01

    The aim of this study was to characterize and determine the bi-functional efficacy of active packaging films produced with starch (4%) and glycerol (1.0%), reinforced with cellulose nanocrystals (0-1%) and activated with alcoholic extracts of red propolis (0.4 to 1.0%). The cellulose nanocrystals used in this study were extracted from licuri leaves. The films were characterized using moisture, water-activity analyses and water vapor-permeability tests and were tested regarding their total phenolic compounds and mechanical properties. The antimicrobial and antioxidant efficacy of the films were evaluated by monitoring the use of the active films for packaging cheese curds and butter, respectively. The cellulose nanocrystals increased the mechanical strength of the films and reduced the water permeability and water activity. The active film had an antimicrobial effect on coagulase-positive staphylococci in cheese curds and reduced the oxidation of butter during storage. PMID:25383783

  5. Bi-Functional Biobased Packing of the Cassava Starch, Glycerol, Licuri Nanocellulose and Red Propolis

    PubMed Central

    Costa, Samantha Serra; Druzian, Janice Izabel; Machado, Bruna Aparecida Souza; de Souza, Carolina Oliveira; Guimarães, Alaíse Gil

    2014-01-01

    The aim of this study was to characterize and determine the bi-functional efficacy of active packaging films produced with starch (4%) and glycerol (1.0%), reinforced with cellulose nanocrystals (0–1%) and activated with alcoholic extracts of red propolis (0.4 to 1.0%). The cellulose nanocrystals used in this study were extracted from licuri leaves. The films were characterized using moisture, water-activity analyses and water vapor-permeability tests and were tested regarding their total phenolic compounds and mechanical properties. The antimicrobial and antioxidant efficacy of the films were evaluated by monitoring the use of the active films for packaging cheese curds and butter, respectively. The cellulose nanocrystals increased the mechanical strength of the films and reduced the water permeability and water activity. The active film had an antimicrobial effect on coagulase-positive staphylococci in cheese curds and reduced the oxidation of butter during storage. PMID:25383783

  6. Secrets of Successful Homeschooling

    ERIC Educational Resources Information Center

    Rivero, Lisa

    2011-01-01

    Parents who homeschool gifted children often find the daily practice of home education very different from what they had imagined. Gifted children are complex in both personality and learning styles. Parents who say that homeschooling works well for their gifted children have learned from others or discovered on their own several secrets that make…

  7. Salivary Gland Secretion.

    ERIC Educational Resources Information Center

    Dorman, H. L.; And Others

    1981-01-01

    Describes materials and procedures for an experiment utilizing a live dog to demonstrate: (1) physiology of the salivary gland; (2) parasympathetic control of the salivary gland; (3) influence of varying salivary flow rates on sodium and potassium ions, osmolarity and pH; and (4) salivary secretion as an active process. (DS)

  8. Trade-Secret Dispute.

    ERIC Educational Resources Information Center

    Blumenstyk, Goldie

    1994-01-01

    A Michigan court has ruled that a Wayne State University (Michigan) chemistry professor appropriated a trade secret from a Massachusetts chemist for whom he was consulting and incorporated it into his own patent application, violating a written agreement. The university contends its pursuit of the patent was not improper. (MSE)

  9. US weapons secrets revealed

    SciTech Connect

    Norris, R.S.; Arkin, W.M.

    1993-03-01

    Extraordinary details have only recently been revealed about the struggle over the control of early U.S. nuclear weapons and their initial deployments abroad. The information comes from a newly declassified top secret report, part of a larger study, The History of the Strategic Arms Competition, 1945-1972, commissioned by Defense Secretary James R. Schlisinger in summer 1974.

  10. Physiology of bile secretion

    PubMed Central

    Esteller, Alejandro

    2008-01-01

    The formation of bile depends on the structural and functional integrity of the bile-secretory apparatus and its impairment, in different situations, results in the syndrome of cholestasis. The structural bases that permit bile secretion as well as various aspects related with its composition and flow rate in physiological conditions will first be reviewed. Canalicular bile is produced by polarized hepatocytes that hold transporters in their basolateral (sinusoidal) and apical (canalicular) plasma membrane. This review summarizes recent data on the molecular determinants of this primary bile formation. The major function of the biliary tree is modification of canalicular bile by secretory and reabsorptive processes in bile-duct epithelial cells (cholangiocytes) as bile passes through bile ducts. The mechanisms of fluid and solute transport in cholangiocytes will also be discussed. In contrast to hepatocytes where secretion is constant and poorly controlled, cholangiocyte secretion is regulated by hormones and nerves. A short section dedicated to these regulatory mechanisms of bile secretion has been included. The aim of this revision was to set the bases for other reviews in this series that will be devoted to specific issues related with biliary physiology and pathology. PMID:18837079

  11. Quantitative analysis of the fermentative metabolism of glycerol in Escherichia coli.

    PubMed

    Cintolesi, Angela; Clomburg, James M; Rigou, Venetia; Zygourakis, Kyriacos; Gonzalez, Ramon

    2012-01-01

    Availability, low price, and high degree of reduction have made glycerol a highly attractive and exploited carbon source for the production of fuels and reduced chemicals. Here we report the quantitative analysis of the fermentative metabolism of glycerol in Escherichia coli through the use of kinetic modeling and metabolic control analysis (MCA) to gain a better understanding of glycerol fermentation and identify key targets for genetic manipulation that could enhance product synthesis. The kinetics of glycerol fermentation in a batch culture was simulated using a dynamic model consisting of mass balances for glycerol, ethanol, biomass, and 11 intracellular metabolites, along with the corresponding kinetic expressions for the metabolism of each species. The model was then used to calculate metabolic control coefficients and elucidate the control structure of the pathways involved in glycerol utilization and ethanol synthesis. The calculated flux control coefficients indicate that the glycolytic flux during glycerol fermentation is almost exclusively controlled by the enzymes glycerol dehydrogenase (encoded by gldA) and dihydroxyacetone kinase (DHAK) (encoded by dhaKLM). In agreement with the MCA findings, overexpression of gldA and dhaKLM led to significant increase in glycerol utilization and ethanol synthesis fluxes. Moreover, overexpression of other enzymes involved in the pathways that mediate glycerol utilization and its conversion to ethanol had no significant impact on glycerol utilization and ethanol synthesis, further validating the MCA predictions. These findings were then applied as a means of increasing the production of ethanol: overexpression of glycerol dehyrdogenase and DHAK enabled the production of 20 g/L ethanol from crude glycerol, a by-product of biodiesel production, indicating the potential for industrial scale conversion of waste glycerol to ethanol under anaerobic conditions. PMID:21858785

  12. Microbial conversion of glycerol into glycolipid biosurfactants, mannosylerythritol lipids, by a basidiomycete yeast, Pseudozyma antarctica JCM 10317(T).

    PubMed

    Morita, Tomotake; Konishi, Masaaki; Fukuoka, Tokuma; Imura, Tomohiro; Kitamoto, Dai

    2007-07-01

    Microbial conversion of glycerol into functional bio-based materials was investigated, aiming to facilitate the utilization of waste glycerol. A basidiomycete yeast, Pseudozyma antarctica JCM 10317, efficiently produced mannosylerythritol lipids (MELs) as glycolipid biosurfactants from glycerol. The amount of MEL yield reached 16.3 g l(-1) by intermittent feeding of glycerol. PMID:17697987

  13. Choline or methionine reverses impaired secretion of VLDL by hepatocytes from choline-deficient rats

    SciTech Connect

    Yao, Z.; Vance, D.E.

    1987-05-01

    Male rats fed a choline-deficient (CD) diet for three days accumulated triacylglycerol (TG) in the liver. Hepatocytes from these rats were cultured and maintained in a medium + choline. The rate of secretion of TG was reduced by 50% in the CD cells. Correspondingly, (/sup 3/H)oleate and (/sup 3/H)glycerol were incorporated at a 2-fold higher rate into TG secreted by choline-supplemented cells compared to CD cells. Isolation of lipoprotein fractions by ultracentrifugation showed that the reduced secretion of TG by CD hepatocytes was mainly due to an impaired secretion of very low density lipoprotein (VLDL). Incorporation of (/sup 3/H)leucine into secreted apoB/sub H/, apoB/sub L/ and apoE was markedly reduced in CD cells compared to choline-supplemented cells. Secretion of high density lipoprotein was not reduced in the CD hepatocytes. Normal secretion of VLDL was resumed upon addition of methionine to the CD cells.

  14. 1,3-Propanediol production from glycerol with Lactobacillus diolivorans.

    PubMed

    Pflügl, Stefan; Marx, Hans; Mattanovich, Diethard; Sauer, Michael

    2012-09-01

    The aim of this study was to evaluate the natural producer Lactobacillus diolivorans as potential production organism of 1,3-propanediol from glycerol. Different cultivation parameters, such as oxygen supply, feeding-strategy, or medium composition have been tested in batch and fed-batch cultivations. The 1,3-propanediol concentration obtained in batch cultivations was 41.7 g/l. This could be increased to 73.7 g/l in a fed-batch co-feeding glucose and glycerol with a molar ratio of 0.1. Yeast extract as part of the MRS cultivation medium could be replaced by nicotinic acid and riboflavin. Furthermore, the addition of Vitamin B(12) to the culture medium increased production by 15% to a final titer of 84.5 g/l 1,3-propanediol. PMID:22728193

  15. Modified silica-based heterogeneous catalysts for etherification of glycerol

    NASA Astrophysics Data System (ADS)

    Gholami, Zahra; Abdullah, Ahmad Zuhairi; Gholami, Fatemeh; Vakili, Mohammadtaghi

    2015-07-01

    The advent of mesoporous silicas such as MCM-41 has provided new opportunities for research into supported metal catalysis. The loading of metals into framework structures and particularly into the pores of porous molecular sieves, has long been of interest because of their potential catalytic activity. Stable heterogeneous mesoporous basic catalysts were synthesized by wet impregnation of MCM-41 with calcium nitrate and lanthanum nitrate. The surface and structural properties of the prepared catalysts were characterized using BET surface analysis, SEM and TEM. MCM-41 and modified MCM-41 were used in the solventless etherification of glycerol to produce diglycerol as the desired product. The reaction was performed at 250 °C for 8 h, and catalyst activity was evaluated. Catalytic etherification over the 20%Ca1.6La0.6/MCM-41 catalyst resulted in the highest glycerol conversion of 91% and diglycerol yield of 43%.

  16. [Sn-glycerol-3-phosphate acyltransferases (GPATs) in plants].

    PubMed

    Liu, Cong; Xiao, Dan-Wang; Shi, Chun-Lin; Hu, Xue-Fang; Wu, Ke-Bin; Guan, Chun-Yun; Xiong, Xing-Hua

    2013-12-01

    Sn-glycerol-3-phosphate acyltransferase (GPAT) catalyzes the acylation at sn-1 position of glycerol-3-phosphate to produce lysophosphatidic acid (LPA) in an acyl-CoA or acyl-ACP-dependent manner, which is the initial and rate-determining step of TAG biosynthetic pathway. Some GPATs have sn-2 transfer activity. Part members of the GPAT gene family have been cloned from different plant species. Based on their subcellular localizations, GPATs can be classified into three types, plastid GPATs, mitochondria GPATs and endoplasmic reticulum GPATs. GPATs exhibit diverse biochemical properties and are involved in synthesis of several lipids such as TAG, suberin, and cutin which play important roles in the growth and development of plants. This review summarized the current understanding of the chromosomal locus and gene structure of GPAT genes and the subcellular localization, sn-2 regiospecificity, substrates specialty, and functions of GPATs in plants. PMID:24645344

  17. Biomass Pretreatment using Ionic Liquid and Glycerol Mixtures

    NASA Astrophysics Data System (ADS)

    Lynam, Joan Goerss

    Lignocellulosic biomass is a renewable, sustainable resource that can replace or supplement fossil fuels use for liquid fuels and chemicals. However, its recalcitrant structure including interwoven cellulose, hemicelluloses, and lignin biomacromolecules is challenging to deconstruct. Pretreating biomass so that it can be converted to useful liquids dominates process economics. Many pretreatment methods exist, but most require hazardous chemicals or processing conditions. Many ionic liquids (ILs), salts molten below 100°C, can be used to deconstruct lignocellulosic biomass and are less hazardous than the volatile organic compounds typically used. While effective, relatively safe, and recyclable, ILs are expensive. To reduce costs, dilution with other safe compounds is desirable, if there is no impact on deconstruction efficiency. Glycerol, a food additive, is inexpensive and becoming even more so since it is a by-product of the burgeoning biodiesel industry. Use of glycerol as an additive or diluent for ILs is extensively evaluated in this work. Rice hulls are an abundant biomass, with over 100 million tons produced per year, but with little practical use. The IL 1-ethyl-3-methylimidazolium formate ([C2mim][O2CH] or EMIM Form) when mixed with an equal amount of glycerol has been shown to be effective in pretreating rice hulls. Ambient pressure, a pretreatment temperature of 110°C, and a reaction time of three hours produced rice hulls that could be enzymatically hydrolyzed to give reasonably good glucose and xylose yields considering the recalcitrance of this silica-armored biomass. The IL [C2mim][O2CH] was also effective when mixed with an equal amount of glycerol to pretreat loblolly pine, a fast-growing softwood. Loblolly pine was pretreated at 140°C for three hours to produce a solid rich in cellulose and hemicelluloses, while a lignin-rich product could be precipitated from the IL. Similar products were obtained from pretreatment with a mixture of 75% 1

  18. The effect of glycerol treatment on crab muscle fibres

    PubMed Central

    Papir, Dalia

    1973-01-01

    1. Membrane constants of the closer muscle of the ghost crab, Ocypoda cursor, were determined before and after treatment in hypertonic glycerol solution and return to an artificial sea-water (A.S.W.) solution. 2. Muscle contraction was abolished after return of the muscle to A.S.W. 3. The membrane capacitance was reduced from 29·0 μF/cm2 to 10·5 μF/cm2. 4. Other passive properties of the muscle membrane, not dependent on capacitance, were not changed. 5. The presynaptic nerve, transmitter release, post-synaptic sensitivity to transmitter and ionic mechanisms of synaptic action were unaffected by glycerol treatment. 6. More than 60% of the membrane capacitance/unit area is contributed by the complex tubular system. 7. The tubular system in crustacea is necessary for excitation-contraction coupling. PMID:4708897

  19. Modified silica-based heterogeneous catalysts for etherification of glycerol

    SciTech Connect

    Gholami, Zahra; Abdullah, Ahmad Zuhairi Gholami, Fatemeh; Vakili, Mohammadtaghi

    2015-07-22

    The advent of mesoporous silicas such as MCM-41 has provided new opportunities for research into supported metal catalysis. The loading of metals into framework structures and particularly into the pores of porous molecular sieves, has long been of interest because of their potential catalytic activity. Stable heterogeneous mesoporous basic catalysts were synthesized by wet impregnation of MCM-41 with calcium nitrate and lanthanum nitrate. The surface and structural properties of the prepared catalysts were characterized using BET surface analysis, SEM and TEM. MCM-41 and modified MCM-41 were used in the solventless etherification of glycerol to produce diglycerol as the desired product. The reaction was performed at 250 °C for 8 h, and catalyst activity was evaluated. Catalytic etherification over the 20%Ca{sub 1.6}La{sub 0.6}/MCM-41 catalyst resulted in the highest glycerol conversion of 91% and diglycerol yield of 43%.

  20. Influence of heat shock on glycerol production in alcohol fermentation.

    PubMed

    Berovic, Marin; Pivec, Aleksandra; Kosmerl, Tatjana; Wondra, Mojmir; Celan, Stefan

    2007-02-01

    The influence of single and double heat shocks induced during the exponential growth phase of the Saccharomyces cerevisiae fermentation of cultivar Sauvignon Blanc grape must was examined. Rapid temperature changes from 18 degrees C to 34 degrees C have been applied. The effect of the duration of exposure to a high temperature has been analyzed. By the applications of a single heat shock and a double heat shock, up to 8.2 g l(-1) and 11.0 g l(-1) glycerol have been produced, respectively. To prevent the evaporation of fine wine bouquet compounds during the temperature changes, reflux coolers on the top of bioreactors have been employed. By using this method, glycerol production was increased by up to 65%. PMID:17368395

  1. Glycerol-3-Phosphate-Induced Catabolite Repression in Escherichia coli

    PubMed Central

    Eppler, Tanja; Postma, Pieter; Schütz, Alexandra; Völker, Uwe; Boos, Winfried

    2002-01-01

    The formation of glycerol-3-phosphate (G3P) in cells growing on TB causes catabolite repression, as shown by the reduction in malT expression. For this repression to occur, the general proteins of the phosphoenolpyruvate-dependent phosphotransferase system (PTS), in particular EIIAGlc, as well as the adenylate cyclase and the cyclic AMP-catabolite activator protein system, have to be present. We followed the level of EIIAGlc phosphorylation after the addition of glycerol or G3P. In contrast to glucose, which causes a dramatic shift to the dephosphorylated form, glycerol or G3P only slightly increased the amount of dephosphorylated EIIAGlc. Isopropyl-β-d-thiogalactopyranoside-induced overexpression of EIIAGlc did not prevent repression by G3P, excluding the possibility that G3P-mediated catabolite repression is due to the formation of unphosphorylated EIIAGlc. A mutant carrying a C-terminally truncated adenylate cyclase was no longer subject to G3P-mediated repression. We conclude that the stimulation of adenylate cyclase by phosphorylated EIIAGlc is controlled by G3P and other phosphorylated sugars such as d-glucose-6-phosphate and is the basis for catabolite repression by non-PTS compounds. Further metabolism of these compounds is not necessary for repression. Two-dimensional polyacrylamide gel electrophoresis was used to obtain an overview of proteins that are subject to catabolite repression by glycerol. Some of the prominently repressed proteins were identified by peptide mass fingerprinting. Among these were periplasmic binding proteins (glutamine and oligopeptide binding protein, for example), enzymes of the tricarboxylic acid cycle, aldehyde dehydrogenase, Dps (a stress-induced DNA binding protein), and d-tagatose-1,6-bisphosphate aldolase. PMID:12003946

  2. Selective oxidation of glycerol under acidic conditions using gold catalysts

    SciTech Connect

    Villa, Alberto; Veith, Gabriel M; Prati, Laura

    2010-01-01

    H-mordenite-supported PtAu nanoparticles are highly active and selective in the oxidation of glycerol under acidic conditions, which allows the direct preparation of free acids (see picture). The high selectivity for C{sub 3} compounds results from the negligible formation of H{sub 2}O{sub 2}, in contrast to PtAu nanoparticles supported on activated carbon.

  3. Metabolic Engineering of Glycerol Production in Saccharomyces cerevisiae

    PubMed Central

    Overkamp, Karin M.; Bakker, Barbara M.; Kötter, Peter; Luttik, Marijke A. H.; van Dijken, Johannes P.; Pronk, Jack T.

    2002-01-01

    Inactivation of TPI1, the Saccharomyces cerevisiae structural gene encoding triose phosphate isomerase, completely eliminates growth on glucose as the sole carbon source. In tpi1-null mutants, intracellular accumulation of dihydroxyacetone phosphate might be prevented if the cytosolic NADH generated in glycolysis by glyceraldehyde-3-phosphate dehydrogenase were quantitatively used to reduce dihydroxyacetone phosphate to glycerol. We hypothesize that the growth defect of tpi1-null mutants is caused by mitochondrial reoxidation of cytosolic NADH, thus rendering it unavailable for dihydroxyacetone-phosphate reduction. To test this hypothesis, a tpi1Δ nde1Δ nde2Δ gut2Δ quadruple mutant was constructed. NDE1 and NDE2 encode isoenzymes of mitochondrial external NADH dehydrogenase; GUT2 encodes a key enzyme of the glycerol-3-phosphate shuttle. It has recently been demonstrated that these two systems are primarily responsible for mitochondrial oxidation of cytosolic NADH in S. cerevisiae. Consistent with the hypothesis, the quadruple mutant grew on glucose as the sole carbon source. The growth on glucose, which was accompanied by glycerol production, was inhibited at high-glucose concentrations. This inhibition was attributed to glucose repression of respiratory enzymes as, in the quadruple mutant, respiratory pyruvate dissimilation is essential for ATP synthesis and growth. Serial transfer of the quadruple mutant on high-glucose media yielded a spontaneous mutant with much higher specific growth rates in high-glucose media (up to 0.10 h−1 at 100 g of glucose · liter−1). In aerated batch cultures grown on 400 g of glucose · liter−1, this engineered S. cerevisiae strain produced over 200 g of glycerol · liter−1, corresponding to a molar yield of glycerol on glucose close to unity. PMID:12039737

  4. Enhanced succinate production from glycerol by engineered Escherichia coli strains.

    PubMed

    Li, Qing; Wu, Hui; Li, Zhimin; Ye, Qin

    2016-10-01

    In this study, an engineered strain Escherichia coli MLB (ldhA(-)pflB(-)) was constructed for production of succinate from glycerol. The succinate yield was 0.37mol/mol in anaerobic culture, however, the growth and glycerol consumption rates were very slow, resulting in a low succinate level. Two-stage fermentation was performed in flasks, and the succinate yield reached 0.93mol/mol, but the succinate titer was still low. Hence, overexpression of malate dehydrogenase, malic enzyme, phosphoenolpyruvate (PEP) carboxylase and PEP carboxykinase (PCK) from E. coli, and pyruvate carboxylase from Corynebacterium glutamicum in MLB was investigated for improving succinate production. Overexpression of PCK resulted in remarkable enhancement of glycerol consumption and succinate production. In flask experiments, the succinate concentration reached 118.1mM, and in a 1.5-L bioreactor the succinate concentration further increased to 360.2mM. The highest succinate yield achieved 0.93mol/mol, which was 93% of the theoretical yield, in the anaerobic stage. PMID:27371794

  5. The Pichia pastoris transmembrane protein GT1 is a glycerol transporter and relieves the repression of glycerol on AOX1 expression.

    PubMed

    Zhan, Chunjun; Wang, Songwei; Sun, Yang; Dai, Xiaofeng; Liu, Xiuxia; Harvey, Linda; McNeil, Brian; Yang, Yankun; Bai, Zhonghu

    2016-06-01

    Promoter of alcohol oxidase I (PAOX1) is the most efficient promoter involved in the regulation of recombinant protein expression in Pichia pastoris (P. pastoris). PAOX1 is tightly repressed by the presence of glycerol in the culture medium; thus, glycerol must be exhausted before methanol can be taken up by P. pastoris and the expression of the heterologous protein can be induced. In this study, a candidate glycerol transporter (GT1, GeneID: 8197545) was identified, and its role was confirmed by further studies (e.g. bioinformatics analysis, heterologous complementation in Schizosaccharomyces pombe (S. pombe)). When GT1 is co-expressed with enhanced green fluorescent protein (EGFP), it localizes to the membrane and S. pombe carrying gt1 but not the wild-type strain can grow on medium containing glycerol as the sole carbon source. The present study is the first to report that AOX1 in the X-33Δgt1 mutant can achieve constitutive expression in medium containing glycerol; thus, knocking down gt1 can eliminate the glycerol repression of PAOX1 in P. pastoris These results suggest that the glycerol transporter may participate in the process of PAOX1 inhibition in glycerol medium. PMID:27189360

  6. Extracellular secretion of recombinant proteins

    SciTech Connect

    Linger, Jeffrey G.; Darzins, Aldis

    2014-07-22

    Nucleic acids encoding secretion signals, expression vectors containing the nucleic acids, and host cells containing the expression vectors are disclosed. Also disclosed are polypeptides that contain the secretion signals and methods of producing polypeptides, including methods of directing the extracellular secretion of the polypeptides. Exemplary embodiments include cellulase proteins fused to secretion signals, methods to produce and isolate these polypeptides, and methods to degrade lignocellulosic biomass.

  7. Induced thermal dynamics in the melt of glycerol and aerosil dispersions.

    PubMed

    Sharma, Dipti; Iannacchione, Germano S

    2007-03-01

    A high-resolution calorimetric spectroscopy study has been performed on pure glycerol and colloidal dispersions of an aerosil gel in glycerol covering a wide range of temperatures from 300 to 380 K, deep in the liquid phase of glycerol. The colloidal glycerol+aerosil samples with 0.07, 0.14, and 0.32 g of silica per cm3 of glycerol reveal activated energy (thermal) dynamics at temperatures well above the Tg of the pure glycerol. The onset of these dynamics appears to be due to the frustration or pinning imposed by the silica gel on the glycerol liquid and is apparently a long-range, cooperative phenomena. Since this behavior begins to manifest itself at relatively low silica densities (large mean void length compared to the size of a glycerol molecule) and speeds up with increasing density, these induced dynamics are likely due to a coupling between the flexible aerosil gel and large groups of glycerol molecules mediated by mutual hydrogen bonding. This is supported by the lack of such thermal dynamics in pure aerosil gels, pure glycerol, or aerosil gels dispersed in a non-glass-forming, non-hydrogen-bonding, liquid crystal under nearly identical experimental conditions. The study of such frustrated colloids may provide a unique avenue for illuminating the physics of glasses. PMID:17362111

  8. Measurement of serum total glycerides and free glycerol by high-performance liquid chromatography.

    PubMed

    Li, Hongxia; Dong, Jun; Chen, Wenxiang; Wang, Shu; Guo, Hanbang; Man, Yong; Mo, Peisheng; Li, Jianzhai

    2006-09-01

    Serum levels of total glycerides and free glycerol are important indices of lipid metabolism and cardiovascular disease risk. Convenient enzymatic methods of measurement have been available, but they are susceptible to interference. Situations exist in both research and clinical laboratories in which more specific and precise methods are needed. We developed HPLC methods for the measurement of serum total glycerides and free glycerol. For total glycerides, serum was mixed with an internal standard (1,2,4-butanetriol) and treated with alcoholic sodium hydroxide to hydrolyze glycerides to glycerol. After deproteinization with tungstic acid, the glycerol was benzoylated with an optimized Schotten-Baumann reaction and analyzed by HPLC. For free glycerol, serum was equilibrated with the internal standard and deproteinized with tungstic acid to remove the glycerides. The glycerol was benzoylated and analyzed as for total glycerol. Various factors were investigated, and no significant sources of interference were detected. The total coefficients of variation ranged from 0.7% to 2.0% for total glycerides and from 1.7% to 3.2% for free glycerol. The analytical recoveries ranged from 98.5% to 101.6%. In conclusion, simple and reliable HPLC methods for serum total glycerides and free glycerol have been developed. The methods may also be used for the analyses of glycerol or glycerides in other biological samples. PMID:16788212

  9. Effect of Glycerol Water Binary Mixtures on the Structure and Dynamics of Protein Solutions

    SciTech Connect

    Ghattyvenkatakrishna, Pavan K; Carri, Gustavo A.

    2014-01-01

    We have performed 20ns of fully atomistic molecular dynamics simulations of Hen Egg-White Lysozyme in 0, 10, 20, 30 and 100% by weight of glycerol in water to better understand the microscopic physics behind the bioprotection offered by glycerol to naturally occuring biological systems. The sovlent exposure of protein surface residues changes when glycerol is introduced. The dynamic behavior of the protein, as quantified by the Incoherent Intermediate Scattering Function, shows a non-monotonic dependence on glycerol content. The fluctuations of the protein residues with respect to each other were found to be similar in all water containing solvents; but different from the pure glycerol case. The increase in the number of protein glycerol hydrogen bonds in glycerol water binary mixtures explains the slowing down of protein dynamics as the glycerol content increases. We also explored the dynamic behavior of the hydration layer. We show that the short-length scale dynamics of this layer are insenstive to glycerol concentration. However, the long-length scale behavior shows a significant dependence on glycerol content. We also provide insights into the behavior of bound and mobile water molecules.

  10. Excess wing in glass-forming glycerol and LiCl-glycerol mixtures detected by neutron scattering

    DOE PAGESBeta

    Gupta, S.; Arend, N.; Lunkenheimer, P.; Loidl, A.; Stingaciu, L.; Jalarvo, N.; Mamontov, E.; Ohl, M.

    2015-01-22

    The relaxational dynamics in glass-forming glycerol and glycerol mixed with LiCl is investigated using different neutron scattering techniques. The performed neutron spin echo experiments, which extend up to relatively long relaxation time scales of the order of 10 ns, should allow for the detection of contributions from the so-called excess wing. This phenomenon, whose microscopic origin is controversially discussed, arises in a variety of glass formers and, until now, was almost exclusively investigated by dielectric spectroscopy and light scattering. In conclusion, we show here that the relaxational process causing the excess wing can also be detected by neutron scattering, whichmore » directly couples to density fluctuations.« less

  11. Flavor impacts of glycerol in the processing of yeast fermented beverages: a review.

    PubMed

    Zhao, Xiangdong; Procopio, Susanne; Becker, Thomas

    2015-12-01

    Glycerol contributes to the beverage body and fullness. Moreover, it also influences the flavor intensity. As a major byproduct, glycerol not only serves critical roles in yeast osmoregulation and redox balancing, but also acts as the carbon competitor against ethanol in alcoholic fermentation. Therefore, increasing glycerol yield benefits both the flavor and ethanol reduction for the fermented beverages. Glycerol yield has been elevated either by fermentation optimization or by yeast genetic modification. The fermentation optimizations reached maximum 14 g/L glycerol through screening yeast strains and optimizing fermentation parameters. Meanwhile the yeast overexpressing GPD1 (encoding glycerol-3-phosphate dehydrogenase) produced up to 6 folds more glycerol for beer and wine. Except for glycerol improvement, the genetically modified yeasts accumulated dramatically undesirable compounds such as acetaldehyde, acetate and acetoin which are detrimental for beverage flavor. In comparison, the natural high glycerol producers showed strain-specific manner on the yeast-derived aroma compounds like volatile acids, fusel alcohols, esters, and aldehydes. Temperature, sugar concentration, nitrogen composition, oxygen and pH-value, which influence glycerol biosynthesis, also obtained various effects on the production of aromatic compounds. In the current review, we firstly deliberate the organoleptic contributions of glycerol for fermented beverages. Furthermore, glycerol optimization strategies are discussed regarding to the yield improvement, the genes expressions, the overall flavor impacts and the feasibilities in beverage applications. Lastly, for improving beverage flavor by glycerol optimization, a high-throughput platform is proposed to increase the screening capacity of yeast strains and parameters in the processing of fermented beverages. PMID:26604336

  12. Cell secretion: an update

    PubMed Central

    Jeremic, A

    2008-01-01

    This past decade has witnessed the publication of a flurry of scientific papers and reports on the subject of cell secretion, following discovery of a permanent plasma membrane structure termed ‘porosome’ and its determination as the universal secretory machinery in cells. This discovery has led to a paradigm shift in our understanding of the secretory process, demonstrating that membrane-bound secretory vesicles transiently dock and fuse at the porosome base to release their contents to the cell exterior. The regulated release of intravesicular contents during cell secretion is governed by dilation of the porosome opening to the outside, and the extent of vesicle swelling. In agreement, a great number of articles have been written and studies performed, which are briefly discussed in this article. PMID:18363838

  13. Proactive quantum secret sharing

    NASA Astrophysics Data System (ADS)

    Qin, Huawang; Dai, Yuewei

    2015-11-01

    A proactive quantum secret sharing scheme is proposed, in which the participants can update their key shares periodically. In an updating period, one participant randomly generates the EPR pairs, and the other participants update their key shares and perform the corresponding unitary operations on the particles of the EPR pairs. Then, the participant who generated the EPR pairs performs the Bell-state measurement and updates his key share according to the result of the Bell-state measurement. After an updating period, each participant can change his key share, but the secret is changeless, and the old key shares will be useless even if they have been stolen by the attacker. The proactive property of our scheme is very useful to resist the mobile attacker.

  14. Generalized quantum secret sharing

    SciTech Connect

    Singh, Sudhir Kumar; Srikanth, R.

    2005-01-01

    We explore a generalization of quantum secret sharing (QSS) in which classical shares play a complementary role to quantum shares, exploring further consequences of an idea first studied by Nascimento, Mueller-Quade, and Imai [Phys. Rev. A 64, 042311 (2001)]. We examine three ways, termed inflation, compression, and twin thresholding, by which the proportion of classical shares can be augmented. This has the important application that it reduces quantum (information processing) players by replacing them with their classical counterparts, thereby making quantum secret sharing considerably easier and less expensive to implement in a practical setting. In compression, a QSS scheme is turned into an equivalent scheme with fewer quantum players, compensated for by suitable classical shares. In inflation, a QSS scheme is enlarged by adding only classical shares and players. In a twin-threshold scheme, we invoke two separate thresholds for classical and quantum shares based on the idea of information dilution.

  15. Impact of impurities in biodiesel-derived crude glycerol on the fermentation by Clostridium pasteurianum ATCC 6013.

    PubMed

    Venkataramanan, Keerthi P; Boatman, Judy J; Kurniawan, Yogi; Taconi, Katherine A; Bothun, Geoffrey D; Scholz, Carmen

    2012-02-01

    During the production of biodiesel, crude glycerol is produced as a byproduct at 10% (w/w). Clostridium pasteurianum has the inherent potential to grow on glycerol and produce 1,3-propanediol and butanol as the major products. Growth and product yields on crude glycerol were reported to be slower and lower, respectively, in comparison to the results obtained from pure glycerol. In this study, we analyzed the effect of each impurity present in the biodiesel-derived crude glycerol on the growth and metabolism of glycerol by C. pasteurianum. The crude glycerol contains methanol, salts (in the form of potassium chloride or sulfate), and fatty acids that were not transesterified. Salt and methanol were found to have no negative effects on the growth and metabolism of the bacteria on glycerol. The fatty acid with a higher degree of unsaturation, linoleic acid, was found to have strong inhibitory effect on the utilization of glycerol by the bacteria. The fatty acid with lower or no degrees of unsaturation such as stearic and oleic acid were found to be less detrimental to substrate utilization. The removal of fatty acids from crude glycerol by acid precipitation resulted in a fermentation behavior that is comparable to the one on pure glycerol. These results show that the fatty acids in the crude glycerol have a negative effect by directly affecting the utilization of glycerol as the carbon source, and hence their removal from crude glycerol is an essential step towards the utilization of crude glycerol. PMID:22202963

  16. Studies on Freezing RAM Semen in Absence of Glycerol.

    NASA Astrophysics Data System (ADS)

    Abdelnaby, Abdelhady Abdelhakeam

    1988-12-01

    Glycerol is widely used as a major cryoprotective agent for freezing spermatozoa of almost all species. However, it reduces fertility of sheep inseminated cervically compared with intrauterine insemination. Studies were conducted to develop a method and procedure for freezing ram semen in the absence of glycerol. Post -thaw survival of ram spermatozoa frozen in the absence of glycerol was affected by time and temperature after collection and before dilution and time after dilution and before freezing. Increase in time at 5^ circC before or after dilution and before freezing increased both post-thaw motility and number of cells passing through Sephadex filter. A cold dilution method was developed. Slow cooling of fresh ram semen and diluting at 5^circ C 2-3 hr. after collection, then freezing 1 hr. after dilution improved both post-thaw motility and number of cells passing through Sephadex filter compared with immediate dilution at 30-37^circC after collection and freezing 3-4 hr. later (P < 0.05). An extender was developed to freeze ram semen in the absence of glycerol. An increase in post-thaw motility was obtained when semen was extended in TES titrated with Tris to pH 7.0 (TEST) and osmotic pressure of 375-400 mOsm/kg, containing 25-30% (v/v) egg yolk and 10% (v/v) maltose. A special device (boat) for freezing was constructed to insure the same height of the sample above LN _2 and thus the same freezing rate from freeze to freeze. Freezing of semen in 0.25cc straws at 5-10 cm above LN_2 (73.8 to 49.5 ^circC/min) yielded higher post-thaw motility than the rates resulted from freezing at 15 cm above LN_2 or 1 cm above LN _2. Faster Thawing in 37^ circC water for 30 sec. (7.8^ circC/sec.) increased post-thaw motility compared with slower thawing in 5 or 20^circ C water (P < 0.05). A lambing rate of 52.2% was obtained in one fertility trial conducted with ram semen frozen without glycerol and 17.1% in a second trial. One injection (IM) of 15 mg PGF_{2alpha}/ewe for

  17. Secret Key Crypto Implementations

    NASA Astrophysics Data System (ADS)

    Bertoni, Guido Marco; Melzani, Filippo

    This chapter presents the algorithm selected in 2001 as the Advanced Encryption Standard. This algorithm is the base for implementing security and privacy based on symmetric key solutions in almost all new applications. Secret key algorithms are used in combination with modes of operation to provide different security properties. The most used modes of operation are presented in this chapter. Finally an overview of the different techniques of software and hardware implementations is given.

  18. Bile Formation and Secretion

    PubMed Central

    Boyer, James L.

    2014-01-01

    Bile is a unique and vital aqueous secretion of the liver that is formed by the hepatocyte and modified down stream by absorptive and secretory properties of the bile duct epithelium. Approximately 5% of bile consists of organic and inorganic solutes of considerable complexity. The bile-secretory unit consists of a canalicular network which is formed by the apical membrane of adjacent hepatocytes and sealed by tight junctions. The bile canaliculi (~1 μm in diameter) conduct the flow of bile countercurrent to the direction of portal blood flow and connect with the canal of Hering and bile ducts which progressively increase in diameter and complexity prior to the entry of bile into the gallbladder, common bile duct, and intestine. Canalicular bile secretion is determined by both bile salt-dependent and independent transport systems which are localized at the apical membrane of the hepatocyte and largely consist of a series of adenosine triphosphate-binding cassette transport proteins that function as export pumps for bile salts and other organic solutes. These transporters create osmotic gradients within the bile canalicular lumen that provide the driving force for movement of fluid into the lumen via aquaporins. Species vary with respect to the relative amounts of bile salt-dependent and independent canalicular flow and cholangiocyte secretion which is highly regulated by hormones, second messengers, and signal transduction pathways. Most determinants of bile secretion are now characterized at the molecular level in animal models and in man. Genetic mutations serve to illuminate many of their functions. PMID:23897680

  19. Methylation and cyclisation of branched glycerol dialkyl glycerol tetraethers as temperature and pH proxies

    NASA Astrophysics Data System (ADS)

    Blaga, C. I.; Reichart, G.-J.; Schouten, S.; Lotter, A.; Sinninghe Damste, J. S.

    2009-04-01

    Branched glycerol dialkyl glycerol tetraethers (GDGTs) containing 0 to 2 cyclopentyl moieties were initially detected in peat deposits [1]. Through the analysis of a global set of soils samples Weijers et al. [2] showed that these GDGTs, probably of bacterial origin, are produced in situ in these soils. Rivers and direct run-off transport these compounds, together with other soil organic matter, to marine [3] and lake sediments [4, 5]. Recently, Weijers et al. [6] defined two indices that are based on branched GDGTs that are distinctively influenced by two environmental factors. The cyclisation ratio of the branched tetraethers (CBT) is related to soil pH and the methylation index of branched tetraethers (MBT) is related to temperature and soil pH. Lake sediments are often used for reconstructing past climatic changes. The presence of branched GDGTs in lake sediments potentially allows reconstruction of temperature and pH of the lake drainage area. We performed organic geochemical analyses on a series of surface sediments from 82 lakes characterised by variable amounts of soil organic matter and from different geographical locations to establish the application of the MBT/CBT as a continental palaeothermometer. Results show that in all of the 82 lakes substantial amounts of branched GDGTs are present (0.1-28% of total GDGTs). Besides the branched GDGTs crenarchaeol was also found in appreciable amounts (on average 23% of the total GDGTs). In the lakes from the northern hemisphere in fact the dominant GDGT is crenarchaeol (38% of total GDGTs) followed by the pentamethylated branched GDGT. In the southern hemisphere on the other hand we observe the hexamethylated branched GDGT as the dominant GDGT and crenarchaeol is here ten times less abundant then in the north (on average 3% of total GDGTs only). The CBT, as defined by Weijers et al. [6], for the entire data set ranges from values close to 0 (0.14 for Lake Ohrid) to 1.7 (Lake Nyos). The MBT ratio, also as defined

  20. Dielectric and specific heat relaxations in vapor deposited glycerol

    SciTech Connect

    Kasina, A. E-mail: wubbenhorst@fys.kuleuven.be; Putzeys, T.; Wübbenhorst, M. E-mail: wubbenhorst@fys.kuleuven.be

    2015-12-28

    Recently [S. Capponi, S. Napolitano, and M. Wübbenhorst, Nat. Commun. 3, 1233 (2012)], vapor deposited glasses of glycerol have been found to recover their super-cooled liquid state via a metastable, ordered liquid (MROL) state characterized by a tremendously enhanced dielectric strength along with a slow-down of the relaxation rate of the structural relaxation. To study the calorimetric signature of this phenomenon, we have implemented a chip-based, differential AC calorimeter in an organic molecular beam deposition setup, which allows the simultaneous measurement of dielectric relaxations via interdigitated comb electrodes and specific heat relaxation spectra during deposition and as function of the temperature. Heating of the as-deposited glass just above the bulk T{sub g} and subsequent cooling/reheating revealed a step-wise increase in c{sub p} by in total 9%, indicating unambiguously that glycerol, through slow vapour deposition, forms a thermodynamically stable glass, which has a specific heat as low as that of crystalline glycerol. Moreover, these glasses were found to show excellent kinetic stability as well as evidenced by both a high onset-temperature and quasi-isothermal recovery measurements at −75 °C. The second goal of the study was to elucidate the impact of the MROL state on the specific heat and its relaxation to the super-cooled state. Conversion of “MROL glycerol” to its “normal” (ordinary liquid, OL) state revealed a second, small (∼2%) increase of the glassy c{sub p}, a little gain (<10%) in the relaxed specific heat, and no signs of deviations of τ{sub cal} from that of normal “bulk” glycerol. These findings altogether suggest that the MROL state in glycerol comprises largely bulk-type glycerol that coexist with a minor volume fraction (<10%) of PVD-induced structural anomalies with a crystal-like calorimetric signature. Based on the new calorimetric findings, we have proposed a new physical picture that assumes the

  1. Electron beam irradiation of maltodextrin and cinnamyl alcohol mixtures: influence of glycerol on cross-linking.

    PubMed

    Khandal, Dhriti; Aggarwal, Manjeet; Suri, Gunjan; Coqueret, Xavier

    2015-03-01

    The influence of glycerol on the electron beam-induced changes in maltodextrins-cinnamyl alcohol (CA) blends is examined with respect to its influence on the degree of chain scission, grafting, and cross-linking. The study is relevant to radiation-induced polysaccharide modification, specifically in the perspective of using blended starch as a thermoplastic material, where glycerol is commonly used as a plasticizer. In the absence of CA, glycerol protects maltodextrin from chromophore formation onto the main chain, but also induces more chain scission. The presence of CA provides efficient radiation-protection against scission. Glycerol is shown to affect the interaction between maltodextrin and CA, most likely in the form of an inclusion complex when glycerol is absent. The global behavior under radiation is therefore governed by the physical interactions between the blend constituents rather than on the role of glycerol role as a plasticizer, or as an OH˙ radical scavenger. PMID:25498620

  2. Co-gasification of hardwood chips and crude glycerol in a pilot scale downdraft gasifier.

    PubMed

    Wei, Lin; Pordesimo, Lester O; Haryanto, Agus; Wooten, James

    2011-05-01

    Seeking appropriate approaches to utilize the crude glycerol produced in biodiesel production is very important for the economic viability and environmental impacts of biodiesel industry. Gasification may be one of options for addressing this issue. Co-gasification of hardwood chips blending with crude glycerol in various loading levels was undertaken in the study involving a pilot scale fixed-bed downdraft gasifier. The results indicated that crude glycerol loading levels affected the gasifier's performance and the quality of syngas produced. When crude glycerol loading level increased, the CO, CH(4), and tar concentrations of the syngas also increased but particle concentration decreased. Though further testing is suggested, downdraft gasifiers could be run well with hardwood chips blending with liquid crude glycerol up to 20 (wt%). The syngas produced had relatively good quality for fueling internal combustion engines. This study provides a considerable way to utilize crude glycerol. PMID:21435871

  3. Bioconversion of glycerol for bioethanol production using isolated Escherichia coli ss1

    PubMed Central

    Suhaimi, Sheril Norliana; Phang, Lai-Yee; Maeda, Toshinari; Abd-Aziz, Suraini; Wakisaka, Minato; Shirai, Yoshihito; Hassan, Mohd Ali

    2012-01-01

    Bioconverting glycerol into various valuable products is one of glycerol's promising applications due to its high availability at low cost and the existence of many glycerol-utilizing microorganisms. Bioethanol and biohydrogen, which are types of renewable fuels, are two examples of bioconverted products. The objectives of this study were to evaluate ethanol production from different media by local microorganism isolates and compare the ethanol fermentation profile of the selected strains to use of glucose or glycerol as sole carbon sources. The ethanol fermentations by six isolates were evaluated after a preliminary screening process. Strain named SS1 produced the highest ethanol yield of 1.0 mol: 1.0 mol glycerol and was identified as Escherichia coli SS1 Also, this isolated strain showed a higher affinity to glycerol than glucose for bioethanol production. PMID:24031858

  4. Value-added processing of crude glycerol into chemicals and polymers.

    PubMed

    Luo, Xiaolan; Ge, Xumeng; Cui, Shaoqing; Li, Yebo

    2016-09-01

    Crude glycerol is a low-value byproduct which is primarily obtained from the biodiesel production process. Its composition is significantly different from that of pure glycerol. Crude glycerol usually contains various impurities, such as water, methanol, soap, fatty acids, and fatty acid methyl esters. Considerable efforts have been devoted to finding applications for converting crude glycerol into high-value products, such as biofuels, chemicals, polymers, and animal feed, to improve the economic viability of the biodiesel industry and overcome environmental challenges associated with crude glycerol disposal. This article reviews recent advances of biological and chemical technologies for value-added processing of crude glycerol into chemicals and polymers, and provides strategies for addressing production challenges. PMID:27004448

  5. Rheological properties of purified illite clays in glycerol/water suspensions

    NASA Astrophysics Data System (ADS)

    Dusenkova, I.; Malers, J.; Berzina-Cimdina, L.

    2015-04-01

    There are many studies about rheological properties of clay-water suspensions, but no published investigations about clay-glycerol suspensions. In this work apparent viscosity of previously purified illite containing clay fraction < 2 μm and glycerol/water suspensions were investigated. Carbonates were removed by dissolution in hydrochloric and citric acids and other non-clay minerals were almost totally removed by centrifugation. All obtained suspensions behaved as shear-thinning fluids with multiple times higher viscosity than pure glycerol/water solutions. Reduction of clay fraction concentration by 5% decreased the apparent viscosity of 50% glycerol/water suspensions approximately 5 times. There was basically no difference in apparent viscosity between all four 50% glycerol/water suspensions, but in 90% glycerol/water suspensions samples from Iecava deposit showed slightly higher apparent viscosity, which could be affected by the particle size distribution.

  6. Quantitative analysis of glycerol in dicarboxylic acid-rich cutins provides insights into Arabidopsis cutin structure.

    PubMed

    Yang, Weili; Pollard, Mike; Li-Beisson, Yonghua; Ohlrogge, John

    2016-10-01

    Cutin is an extracellular lipid polymer that contributes to protective cuticle barrier functions against biotic and abiotic stresses in land plants. Glycerol has been reported as a component of cutin, contributing up to 14% by weight of total released monomers. Previous studies using partial hydrolysis of cuticle-enriched preparations established the presence of oligomers with glycerol-aliphatic ester links. Furthermore, glycerol-3-phosphate 2-O-acyltransferases (sn-2-GPATs) are essential for cutin biosynthesis. However, precise roles of glycerol in cutin assembly and structure remain uncertain. Here, a stable isotope-dilution assay was developed for the quantitative analysis of glycerol by GC/MS of triacetin with simultaneous determination of aliphatic monomers. To provide clues about the role of glycerol in dicarboxylic acid (DCA)-rich cutins, this methodology was applied to compare wild-type (WT) Arabidopsis cutin with a series of mutants that are defective in cutin synthesis. The molar ratio of glycerol to total DCAs in WT cutins was 2:1. Even when allowing for a small additional contribution from hydroxy fatty acids, this is a substantially higher glycerol to aliphatic monomer ratio than previously reported for any cutin. Glycerol content was strongly reduced in both stem and leaf cutin from all Arabidopsis mutants analyzed (gpat4/gpat8, att1-2 and lacs2-3). In addition, the molar reduction of glycerol was proportional to the molar reduction of total DCAs. These results suggest "glycerol-DCA-glycerol" may be the dominant motif in DCA-rich cutins. The ramifications and caveats for this hypothesis are presented. PMID:27211345

  7. Thermal Transitions and Extrusion of Glycerol-Plasticized Whey Protein Mixtures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of glycerol and moisture contents on the thermal transitions of whey protein isolate (WPI) powder-glycerol-water mixtures were studied. Mixtures with ratios of 100:0, 70:30, 60:40 and 50:50 WPI:glycerol on a dry basis (db) were pre-conditioned to 0.34+/-0.01 (25.4±0.4ºC) and 0.48+/-0.02...

  8. Anaerobic fermentation of glycerol in Paenibacillus macerans: metabolic pathways and environmental determinants.

    PubMed

    Gupta, Ashutosh; Murarka, Abhishek; Campbell, Paul; Gonzalez, Ramon

    2009-09-01

    Paenibacillus macerans is one of the species with the broadest metabolic capabilities in the genus Paenibacillus, able to ferment hexoses, deoxyhexoses, pentoses, cellulose, and hemicellulose. However, little is known about glycerol metabolism in this organism, and some studies have reported that glycerol is not fermented. Despite these reports, we found that several P. macerans strains are capable of anaerobic fermentation of glycerol. One of these strains, P. macerans N234A, grew fermentatively on glycerol at a maximum specific growth rate of 0.40 h(-1) and was chosen for further characterization. The use of [U-13C]glycerol and further analysis of extracellular metabolites and proteinogenic amino acids via nuclear magnetic resonance (NMR) spectroscopy allowed identification of ethanol, formate, acetate, succinate, and 1,2-propanediol (1,2-PDO) as fermentation products and demonstrated that glycerol is incorporated into cellular components. A medium formulation with low concentrations of potassium and phosphate, cultivation at acidic pH, and the use of a CO2-enriched atmosphere stimulated glycerol fermentation and are proposed to be environmental determinants of this process. The pathways involved in glycerol utilization and synthesis of fermentation products were identified using NMR spectroscopy in combination with enzyme assays. Based on these studies, the synthesis of ethanol and 1,2-PDO is proposed to be a metabolic determinant of glycerol fermentation in P. macerans N234A. Conversion of glycerol to ethanol fulfills energy requirements by generating one molecule of ATP per molecule of ethanol synthesized. Conversion of glycerol to 1,2-PDO results in the consumption of reducing equivalents, thus facilitating redox balance. Given the availability, low price, and high degree of reduction of glycerol, the high metabolic rates exhibited by P. macerans N234A are of paramount importance for the production of fuels and chemicals. PMID:19617389

  9. Evaluation of optical clearing with the combined liquid paraffin and glycerol mixture

    PubMed Central

    Wang, Jingyi; Liang, Yanmei; Zhang, Shu; Zhou, Yueqiao; Ni, Haiyang; Li, Yan

    2011-01-01

    By scanning biological tissues in vivo and in vitro with optical coherence tomography, it is found that liquid paraffin can enhance the percutaneous penetration of glycerol in deep layers of tissue and take synergistically optical clearing effect with glycerol. It is shown from experimental results that 30% - 50% liquid paraffin glycerol solutions have the best enhancement effect. Considering the refractive index of liquid paraffin and its medicinal value, we think liquid paraffin will play an important role in optical clearing as the penetration enhancer of glycerol in future clinical research. PMID:21833369

  10. The glycerol teichoic acid from the cell wall of Bacillus stearothermophilus B65

    PubMed Central

    Wicken, A. J.

    1966-01-01

    1. A glycerol teichoic acid has been extracted from cell walls of Bacillus stearothermophilus B65 and its structure examined. 2. Trichloroacetic acid-extractable teichoic acid accounted for 68% of the total cell-wall phosphorus and residual material could be hydrolysed to a mixture of products including those characteristic of glycerol teichoic acids. 3. The extracted polymer is composed of glycerol, phosphoric acid, d-glucose and d-alanine. 4. Hydrolysis of the polymer with alkali gave glycerol, 1-O-α-d-glucopyranosylglycerol and its monophosphates, glycerol mono- and di-phosphate, as well as traces of a glucosyldiglycerol triphosphate and a glucosylglycerol diphosphate. 5. The teichoic acid is a polymer of 18 or 19 glycerol phosphate units having α-d-glucopyranosyl residues attached to position 1 of 14 or 15 of the glycerol residues. 6. The glycerol residues are joined by phosphodiester linkages involving positions 2 and 3 in each glycerol. 7. d-Alanine is in ester linkage to the hydroxyl group at position 6 of approximately half of the glucose residues. 8. One in every 13 or 12 polymer molecules bears a phosphomonoester group on position 3 of a glucose residue, the possible significance of which in linkage of the polymer to other wall constituents is discussed. PMID:4290549

  11. Characteristics of droplets ejected from liquid glycerol doped with carbon in laser ablation propulsion

    NASA Astrophysics Data System (ADS)

    Zhi-Yuan, Zheng; Si-Qi, Zhang; Tian, Liang; Lu, Gao; Hua, Gao; Zi-Li, Zhang

    2016-04-01

    The characteristics of droplets ejected from liquid glycerol doped with carbon are investigated in laser ablation propulsion. Results show that carbon content has an effect on both the coupling coefficient and the specific impulse. The doped-carbon moves the laser focal position from the glycerol interior to the surface. This results in a less consumed glycerol and a high specific impulse. An optimal propulsion can be realized by varying carbon content in glycerol. Project supported by the National Natural Science Foundation of China (Grant No. 10905049) and the Fundamental Research Funds for the Central Universities, China (Grant Nos. 53200859165 and 2562010050).

  12. Mechanistic investigation of ultrasonic enhancement of glycerol bioconversion by immobilized Clostridium pasteurianum on silica support.

    PubMed

    Khanna, Swati; Goyal, Arun; Moholkar, Vijayanand S

    2013-06-01

    Glycerol, the principal byproduct of biodiesel production, can be a valuable carbon source for bioconversion into diverse class of compounds. This article attempts to investigate the mechanistic aspects of ultrasound mediated bioconversion of glycerol to ethanol and 1,3-propanediol (1,3-PDO) by immobilized Clostridium pasteurianum cells on silica support. Our approach is of coupling experimental results with simulations of cavitation bubble dynamics and enzyme kinetics. In addition, the statistical analysis (ANOVA) of experimental results was also done. The glycerol uptake by cells was not affected by either immobilization or with ultrasonication. Nonetheless, both immobilization and ultrasonication were found to enhance glycerol consumption. The enhancement effect of ultrasound on glycerol consumption was most marked (175%) at the highest glycerol concentration of 25 g/L (271.7 mM). The highest glycerol consumption (32.4 mM) was seen for 10 g/L (108.7 mM) initial glycerol concentration. The immobilization of cells shifted the metabolic pathway almost completely towards 1,3-PDO. No formation of ethanol was seen with mechanical shaking, while traces of ethanol were detected with ultrasonication. On the basis of analysis of enzyme kinetics parameters, we attribute these results to increased substrate-enzyme affinity and decreased substrate inhibition for 1,3-PDO dehydrogenase in presence of ultrasound that resulted in preferential conversion of glycerol into 1,3-PDO. PMID:23322632

  13. Dynamic shear modulus of glycerol: Corrections due to instrument compliance

    NASA Astrophysics Data System (ADS)

    Schröter, K.; Hutcheson, S. A.; Shi, X.; Mandanici, A.; McKenna, G. B.

    2006-12-01

    A recent article by Shi et al. [J. Chem. Phys.123, 174507 (2005)] reports results from mechanical measurements on three simple inorganic glass formers: glycerol, m-toluidine, and sucrose benzoate. The experiments carried out were stress relaxation, aging, and dynamic (all in shear) using a torsional rheometer, an advanced rheometric expansion system (TA Instruments). The original force rebalance transducer (2KFRT) supplied with the system was replaced with a custom-made load cell (Sensotec) that had a capacity of 20000gcm in torque and 5000g in normal force. The replacement of the load cell was done due to the belief that the main source of compliance in this instrument was from the 2KFRT. With this assumption, the authors published their results for the three materials of interest and compared their results with the techniques of Schröter and Donth [J. Chem. Phys.113, 9101 (2000)] for the measurements on glycerol and reported important differences. These differences were disputed by one of the present authors (Schröter), and the present report shows that the results from Schröter and Donth are correct. We show that the reasons have to do with the instrument compliance being greater than originally thought by Shi et al. Here we examine the effects of platen diameter/geometry on the glycerol dynamic moduli, describe a means to correct dynamic data, present a revised comparison of the corrected data with that of Schröter and Donth, and provide a discussion of future work and conclusions.

  14. Glycerol effects on protein flexibility: a tryptophan phosphorescence study.

    PubMed Central

    Gonnelli, M.; Strambini, G. B.

    1993-01-01

    In exploring the dynamic properties of protein structure, numerous studies have focussed on the dependence of structural fluctuations on solvent viscosity, but the emerging picture is still not well defined. Exploiting the sensitivity of the phosphorescence lifetime of tryptophan to the viscosity of its environment we have used the delayed emission as an intrinsic probe of protein flexibility and investigated the effects of glycerol as a viscogenic cosolvent. The phosphorescence lifetime of alcohol dehydrogenase, alkaline phosphatase, apoazurin and RNase T1, as a function of glycerol concentration was studied at various temperatures. Flexibility data, which refer to rather rigid sites of the globular structures, point out that, for some concentration ranges glycerol, effects on the rate of structural fluctuations of alcohol dehydrogenase and RNase T1 do not obey Kramers' a power law on solvent viscosity and emphasize that cosolvent-induced structural changes can be important, even for inner cores of the macromolecule. When the data is analyzed in terms of Kramers' model, for the temperature range 0-30 degrees C one derives frictional coefficients that are relatively large (0.6-0.7) for RNase T1, where the probe is in a flexible region near the surface of the macromolecule and much smaller, less than 0.2, for the rigid sites of the other proteins. For the latter sites the frictional coefficient rises sharply between 40 and 60 degrees C, and its value correlates weakly with molecular parameters such as the depth of burial or the rigidity of a particular site. For RNase T1, coupling to solvent viscosity increases at subzero temperatures, with the coefficient becoming as large as 1 at -20 degrees C. Temperature effects were interpreted by proposing that solvent damping of internal protein motions is particularly effective for low frequency, large amplitude, structural fluctuations yielding highly flexible conformers of the macromolecule. PMID:8369422

  15. Pre-exercise glycerol hydration improves cycling endurance time

    NASA Technical Reports Server (NTRS)

    Montner, P.; Stark, D. M.; Riedesel, M. L.; Murata, G.; Robergs, R.; Timms, M.; Chick, T. W.

    1996-01-01

    The effects of glycerol ingestion (GEH) on hydration and subsequent cycle ergometer submaximal load exercise were examined in well conditioned subjects. We hypothesized that GEH would reduce physiologic strain and increase endurance. The purpose of Study I (n = 11) was to determine if pre-exercise GEH (1.2 gm/kg glycerol in 26 ml/kg solution) compared to pre-exercise placebo hydration (PH) (26 ml/kg of aspartame flavored water) lowered heart rate (HR), lowered rectal temperature (Tc), and prolonged endurance time (ET) during submaximal load cycle ergometry. The purpose of Study II (n = 7) was to determine if the same pre-exercise regimen followed by carbohydrate oral replacement solution (ORS) during exercise also lowered HR, Tc, and prolonged ET. Both studies were double-blind, randomized, crossover trials, performed at an ambient temperature of 23.5-24.5 degrees C, and humidity of 25-27%. Mean HR was lower by 2.8 +/- 0.4 beats/min (p = 0.05) after GEH in Study I and by 4.4 +/- 1.1 beats/min (p = 0.01) in Study II. Endurance time was prolonged after GEH in Study I (93.8 +/- 14 min vs. 77.4 +/- 9 min, p = 0.049) and in Study II (123.4 +/- 17 min vs. 99.0 +/- 11 min, p = 0.03). Rectal temperature did not differ between hydration regimens in both Study I and Study II. Thus, pre-exercise glycerol-enhanced hyperhydration lowers HR and prolongs ET even when combined with ORS during exercise. The regimens tested in this study could potentially be adapted for endurance activities.

  16. Ghrelin and gastric acid secretion

    PubMed Central

    Yakabi, Koji; Kawashima, Junichi; Kato, Shingo

    2008-01-01

    Ghrelin, a novel growth hormone-releasing peptide, was originally isolated from rat and human stomach. Ghrelin has been known to increase the secretion of growth hormone (GH), food intake, and body weight gain when administered peripherally or centrally. Ghrelin is also known to stimulate the gastric motility and the secretion of gastric acid. In the previous studies, the action of ghrelin on acid secretion was shown to be as strong as that of histamine and gastrin in in-vivo experiment. In the studies, the mechanism for the action of ghrelin was also investigated. It was shown that vagotomy completely inhibited the action of ghrelin on the secretion of gastric acid suggesting that vagal nerve is involved in the mechanism for the action of ghrelin on acid secretion. As famotidine did not inhibit ghrelin-induced acid secretion in the study by Masuda et al, they concluded that histamine was not involved in the action of ghrelin on acid secretion. However, we have shown that famotidine completely inhibited ghrelin-induced acid secretion and histidine decarboxylase (HDC) mRNA was increased in gastric mucosa by ghrelin injection which is inhibited by vagotomy Our results indicate that histamine is involved in the action of ghrelin on acid secretion. Furthermore synergistic action of gastrin and ghrelin on gastric acid secretion was shown. Although gastrin has important roles in postprandial secretion of gastric acid, ghrelin may be related to acid secretion during fasting period or at night. However, further studies are needed to elucidate the physiological role of ghrelin in acid secretion. PMID:19009648

  17. Production of d-Mannitol and Glycerol by Yeasts

    PubMed Central

    Onishi, Hiroshi; Suzuki, Toshiyuki

    1968-01-01

    D-Mannitol has not so far been known as a major product of sugar metabolism by yeasts. Three yeast strains, a newly isolated yeast from soy-sauce mash, Torulopsis versatilis, and T. anomala, were found to be good mannitol producers. Under optimal conditions, the isolate produced mannitol at good yield of 30% of the sugar consumed. Glucose, fructose, mannose, galactose, maltose, glycerol, and xylitol were suitable substrates for mannitol formation. High concentrations of yeast extract, Casamino Acids, NaCl, and KCl in media affected significantly the mannitol yield, whereas high levels of inorganic phosphate did not show any detrimental effect. PMID:5749751

  18. Scattering of water from the glycerol liquid-vacuum interface

    NASA Technical Reports Server (NTRS)

    Benjamin, I.; Wilson, M. A.; Pohorille, A.; Nathanson, G. M.

    1995-01-01

    Molecular dynamics calculations of the scattering of D2O from the glycerol surface at different collision energies are reported. The results for the trapping probabilities and energy transfer are in good agreement with experiments. The calculations demonstrate that the strong attractive forces between these two strongly hydrogen bonding molecules have only a minor effect on the initial collision dynamics. The trapping probability is influenced to a significant extent by the repulsive hard sphere-like initial encounter with the corrugated surface and, only at a later stage, by the efficiency of energy flow in the multiple interactions between the water and the surface molecules.

  19. Protecting Trade Secrets in Canada.

    PubMed

    Courage, Noel; Calzavara, Janice

    2015-01-01

    Patents in the life sciences industries are a key form of intellectual property (IP), particularly for products such as brand-name drugs and medical devices. However, trade secrets can also be a useful tool for many types of innovations. In appropriate cases, trade secrets can offer long-term protection of IP for a lower financial cost than patenting. This type of protection must be approached with caution as there is little room for error when protecting a trade secret. Strong agreements and scrupulous security can help to protect the secret. Once a trade secret is disclosed to the public, it cannot be restored as the owner's property; however, if the information is kept from the public domain, the owner can have a property right of unlimited duration in the information. In some situations patents and trade secrets may be used cooperatively to protect innovation, particularly for manufacturing processes. PMID:25986591

  20. Inhibition of Monoacylglycerol Lipase Activity Decreases Glucose-Stimulated Insulin Secretion in INS-1 (832/13) Cells and Rat Islets

    PubMed Central

    Burritt, Nathan E.; Corkey, Barbara E.; Deeney, Jude T.

    2016-01-01

    Lipid signals derived from lipolysis and membrane phospholipids play an important role in glucose-stimulated insulin secretion (GSIS), though the exact secondary signals remain unclear. Previous reports have documented a stimulatory role of exogenously added mono-acyl-glycerol (MAG) on insulin secretion from cultured β-cells and islets. In this report we have determined effects of increasing intracellular MAG in the β-cell by inhibiting mono-acyl-glycerol lipase (MGL) activity, which catalyzes the final step in triacylglycerol breakdown, namely the hydrolysis of MAG to glycerol and free fatty acid (FA). To determine the role of MGL in GSIS, we used three different pharmacological agents (JZL184, MJN110 and URB602). All three inhibited GSIS and depolarization-induced insulin secretion in INS-1 (832/13). JZL184 significantly inhibited both GSIS and depolarization-induced insulin secretion in rat islets. JZL184 significantly decreased lipolysis and increased both mono- and diacyglycerol species in INS-1 cells. Analysis of the kinetics of GSIS showed that inhibition was greater during the sustained phase of secretion. A similar pattern was observed in the response of Ca2+ to glucose and depolarization but to a lesser degree suggesting that altered Ca2+ handling alone could not explain the reduction in insulin secretion. In addition, a significant reduction in long chain-CoA (LC-CoA) was observed in INS-1 cells at both basal and stimulatory glucose following inhibition of MGL. Our data implicate an important role for MGL in insulin secretion. PMID:26867016

  1. L (+)-lactic acid production by pellet-form Rhizopus oryzae NRRL 395 on biodiesel crude glycerol

    PubMed Central

    2013-01-01

    Background Given its availability and low price, glycerol derived from biodiesel industry has become an ideal feedstock for the production of fuels and chemicals. A solution to reduce the negative environmental problems and the cost of biodiesel is to use crude glycerol as carbon source for microbial growth media in order to produce valuable organic chemicals. In the present paper, crude glycerol was used as carbon substrate for production of L (+)-lactic acid using pelletized fungus R. oryzae NRRL 395 on batch fermentation. More, the experiments were conducted on media supplemented with inorganic nutrients and lucerne green juice. Results Crude and pure glycerols were first used to produce the highest biomass yield of R. oryzae NRRL 395. An enhanced lactic acid production then followed up using fed-batch fermentation with crude glycerol, inorganic nutrients and lucerne green juice. The optimal crude glycerol concentration for cultivating R. oryzae NRRL 395 was 75 g l-1, which resulted in a fungal biomass yield of 0.72 g g-1 in trial without lucerne green juice addition and 0.83 g g-1 in trial with lucerne green juice. The glycerol consumption rate was 1.04 g l-1 h-1 after 48 h in trial with crude glycerol 75 g l-1 while in trial with crude glycerol 10 g l-1 the lowest rate of 0.12 g l-1 h-1 was registered. The highest L (+)-lactic acid yield (3.72 g g-1) was obtained at the crude glycerol concentration of 75 g l-1 and LGJ 25 g l-1, and the concentration of lactic acid was approximately 48 g l-1. Conclusions This work introduced sustainable opportunities for L (+)-lactic acid production via R. oryzae NRRL 395 fermentation on biodiesel crude glycerol media. The results showed good fungal growth on crude glycerol at 75 g l-1 concentration with lucerne green juice supplementation of 25 g l-1. Lucerne green juice provided a good source of nutrients for crude glycerol fermentation, without needs for supplementation with inorganic nutrients

  2. Use of molecular dynamics to assess the biophysiological role of hydroxyl groups in glycerol dyalkyl glycerol teraethers

    NASA Astrophysics Data System (ADS)

    Huguet, Carme; Costenaro, Lionel; Fietz, Susanne; Daura, Xavier

    2015-04-01

    The cell membrane of some Archaea is constituted by lipids that span the whole membrane width and contain two alkyl chains bound by two glycerol groups (glycerol dyalkyl glycerol teraethers or GDGTs). These lipids confer stability to the membrane in mesophile to extremophile environments. Besides the more frequently studied isoprenoid archaeal lipids, both mono- and dihydroxy-GDGTs (OH-GDGT) have been recently reported to occur in marine sediments (1). OH-GDGTs contain up to two cyclopentane moieties and have been identified in both core and intact forms. In 2013, a correlation between OH-GDGTs and temperature was reported, with higher relative OH-GDGT abundances at high latitudes (2,3). The physiological function of the hydroxyl group in a GDGT is not yet known, but given the field results, it could be linked to an adaptation of the membrane to changes in temperature. For hydroxydiether lipid cores in methanogenic bacteria, it has been postulated that the hydroxyl group may alter the cell membrane properties: either extending the polar head group region or creating a hydrophilic pocket (4). It has also been suggested that the hydroxylation of the biphytany (l) moiety may result in enhanced membrane rigidity (1). To improve our understanding of the effect of the hydroxylation on physical properties of membranes, we performed molecular-dynamics simulations of GDGT membranes presenting and lacking these additional OH groups. This is an approach with a great development potential in the archaea lipid field, especially in relation to proxy validation. Our results indicate that the addition of an OH increases the membrane fluidity, thus providing an advantage in cold environments. We also observe a widening of the polar head group area, which could enhance transport. 1. Liu et al. 2012, GCA 2. Huguet et al. 2013, Org. Geochem 3. Fietz et al. 2013 4. Sprott et al. 1990. J. Biol. Chem. 265, 13735-13740.

  3. Characterization of the CDP-2-Glycerol Biosynthetic Pathway in Streptococcus pneumoniae▿ †

    PubMed Central

    Wang, Quan; Xu, Yanli; Perepelov, Andrei V.; Xiong, Wei; Wei, Dongmei; Shashkov, Alexander S.; Knirel, Yuriy A.; Feng, Lu; Wang, Lei

    2010-01-01

    Capsule polysaccharide (CPS) plays an important role in the virulence of Streptococcus pneumoniae and is usually used as the pneumococcal vaccine target. Glycerol-2-phosphate is found in the CPS of S. pneumoniae types 15A and 23F and is rarely found in the polysaccharides of other bacteria. The biosynthetic pathway of the nucleotide-activated form of glycerol-2-phosphate (NDP-2-glycerol) has never been identified. In this study, three genes (gtp1, gtp2, and gtp3) from S. pneumoniae 23F that have been proposed to be involved in the synthesis of NDP-2-glycerol were cloned and the enzyme products were expressed, purified, and assayed for their respective activities. Capillary electrophoresis was used to detect novel products from the enzyme-substrate reactions, and the structure of the product was elucidated using electrospray ionization mass spectrometry and nuclear magnetic resonance spectroscopy. Gtp1 was identified as a reductase that catalyzes the conversion of 1,3-dihydroxyacetone to glycerol, Gtp3 was identified as a glycerol-2-phosphotransferase that catalyzes the conversion of glycerol to glycerol-2-phosphate, and Gtp2 was identified as a cytidylyltransferase that transfers CTP to glycerol-2-phosphate to form CDP-2-glycerol as the final product. The kinetic parameters of Gtp1 and Gtp2 were characterized in depth, and the effects of temperature, pH, and cations on these two enzymes were analyzed. This is the first time that the biosynthetic pathway of CDP-2-glycerol has been identified biochemically; this pathway provides a method to enzymatically synthesize this compound. PMID:20729354

  4. Salmonella-secreted Virulence Factors

    SciTech Connect

    Heffron, Fred; Niemann, George; Yoon, Hyunjin; Kidwai, Afshan S.; Brown, Roslyn N.; McDermott, Jason E.; Smith, Richard D.; Adkins, Joshua N.

    2011-05-01

    In this short review we discuss secreted virulence factors of Salmonella, which directly affect Salmonella interaction with its host. Salmonella secretes protein to subvert host defenses but also, as discussed, to reduce virulence thereby permitting the bacteria to persist longer and more successfully disperse. The type III secretion system (TTSS) is the best known and well studied of the mechanisms that enable secretion from the bacterial cytoplasm to the host cell cytoplasm. Other secretion systems include outer membrane vesicles, which are present in all Gram-negative bacteria examined to date, two-partner secretion, and type VI secretion will also be addressed. Excellent reviews of Salmonella secreted effectors have focused on themes such as actin rearrangements, vesicular trafficking, ubiquitination, and the activities of the virulence factors themselves. This short review is based on S. Typhimurium infection of mice because it is a model of typhoid like disease in humans. We have organized effectors in terms of events that happen during the infection cycle and how secreted effectors may be involved.

  5. Expansible quantum secret sharing network

    NASA Astrophysics Data System (ADS)

    Sun, Ying; Xu, Sheng-Wei; Chen, Xiu-Bo; Niu, Xin-Xin; Yang, Yi-Xian

    2013-08-01

    In the practical applications, member expansion is a usual demand during the development of a secret sharing network. However, there are few consideration and discussion on network expansibility in the existing quantum secret sharing schemes. We propose an expansible quantum secret sharing scheme with relatively simple and economical quantum resources and show how to split and reconstruct the quantum secret among an expansible user group in our scheme. Its trait, no requirement of any agent's assistant during the process of member expansion, can help to prevent potential menaces of insider cheating. We also give a discussion on the security of this scheme from three aspects.

  6. Protease activation in glycerol-based deep eutectic solvents

    PubMed Central

    Zhao, Hua; Baker, Gary A.; Holmes, Shaletha

    2011-01-01

    Deep eutectic solvents (DESs) consisting of mixtures of a choline salt (chloride or acetate form) and glycerol are prepared as easily accessible, biodegradable, and inexpensive alternatives to conventional aprotic cation-anion paired ionic liquids. These DES systems display excellent fluidity coupled with thermal stability to nearly 200 °C. In this work, the transesterification activities of cross-linked proteases (subtilisin and α-chymotrypsin), immobilized on chitosan, were individually examined in these novel DESs. In the 1:2 molar ratio mixture of choline chloride/glycerol containing 3% (v/v) water, cross-linked subtilisin exhibited an excellent activity (2.9 μmo l min−1 g−1) in conjunction with a selectivity of 98% in the transesterification reaction of N-acetyl-L-phenylalanine ethyl ester with 1-propanol. These highly encouraging results advocate more extensive exploration of DESs in protease-mediated biotransformations of additional polar substrates and use of DESs in biocatalysis more generally. PMID:21909232

  7. Dynamical and orientational structural crossovers in low-temperature glycerol

    NASA Astrophysics Data System (ADS)

    Seyedi, Salman; Martin, Daniel R.; Matyushov, Dmitry V.

    2016-07-01

    Mean-square displacements of hydrogen atoms in glass-forming materials and proteins, as reported by incoherent elastic neutron scattering, show kinks in their temperature dependence. This crossover, known as the dynamical transition, connects two approximately linear regimes. It is often assigned to the dynamical freezing of subsets of molecular modes at the point of equality between their corresponding relaxation times and the instrumental observation window. The origin of the dynamical transition in glass-forming glycerol is studied here by extensive molecular dynamics simulations. We find the dynamical transition to occur for both the center-of-mass translations and the molecular rotations at the same temperature, insensitive to changes of the observation window. Both the translational and rotational dynamics of glycerol show a dynamic crossover from the structural to a secondary relaxation at the temperature of the dynamical transition. A significant and discontinuous increase in the orientational Kirkwood factor and in the dielectric constant is observed in the same range of temperatures. No indication is found of a true thermodynamic transition to an ordered low-temperature phase. We therefore suggest that all observed crossovers are dynamic in character. The increase in the dielectric constant is related to the dynamic freezing of dipolar domains on the time scale of simulations.

  8. Protease activation in glycerol-based deep eutectic solvents.

    PubMed

    Zhao, Hua; Baker, Gary A; Holmes, Shaletha

    2011-11-01

    Deep eutectic solvents (DESs) consisting of mixtures of a choline salt (chloride or acetate form) and glycerol are prepared as easily accessible, biodegradable, and inexpensive alternatives to conventional aprotic cation-anion paired ionic liquids. These DES systems display excellent fluidity coupled with thermal stability to nearly 200 °C. In this work, the transesterification activities of cross-linked proteases (subtilisin and α-chymotrypsin), immobilized on chitosan, were individually examined in these novel DESs. In the 1:2 molar ratio mixture of choline chloride/glycerol containing 3% (v/v) water, cross-linked subtilisin exhibited an excellent activity (2.9 μmo l min(-1) g(-1)) in conjunction with a selectivity of 98% in the transesterification reaction of N-acetyl-L-phenylalanine ethyl ester with 1-propanol. These highly encouraging results advocate more extensive exploration of DESs in protease-mediated biotransformations of additional polar substrates and use of DESs in biocatalysis more generally. PMID:21909232

  9. Substrate versatility of polyhydroxyalkanoate producing glycerol grown bacterial enrichment culture.

    PubMed

    Moralejo-Gárate, Helena; Kleerebezem, Robbert; Mosquera-Corral, Anuska; Campos, José Luis; Palmeiro-Sánchez, Tania; van Loosdrecht, Mark C M

    2014-12-01

    Waste-based polyhydroxyalkanoate (PHA) production by bacterial enrichments generally follows a three step strategy in which first the wastewater is converted into a volatile fatty acid rich stream that is subsequently used as substrate in a selector and biopolymer production units. In this work, a bacterial community with high biopolymer production capacity was enriched using glycerol, a non-fermented substrate. The substrate versatility and PHA production capacity of this community was studied using glucose, lactate, acetate and xylitol as substrate. Except for xylitol, very high PHA producing capacities were obtained. The PHA accumulation was comparable or even higher than with glycerol as substrate. This is the first study that established a high PHA content (≈70 wt%) with glucose as substrate in a microbial enrichment culture. The results presented in this study support the development of replacing pure culture based PHA production by bacterial enrichment cultures. A process where mixtures of substrates can be easily handled and the acidification step can potentially be avoided is described. PMID:25213684

  10. Stability conditions and mechanism of cream soaps: role of glycerol.

    PubMed

    Sagitani, Hiromichi

    2014-01-01

    Fatty acids, fatty acid potassium soaps, glycerol and water are essential ingredients in the production of stable cream soaps. In this study, the behavior of these components in solution was investigated to elucidate the stability conditions and mechanism of cream soaps. It was determined that the cream soaps were a dispersion of 1:1 acid soap (1:1 molar ratio of potassium soap/fatty acid) crystals in the lamellar gel phase, which has confirmed from the phase behavior diagrams and small angle X-ray scattering data. Glycerol was crucial ingredient in the formation of the lamellar gel phase. The cleansing process of the cream soaps was also evaluated using the same diagrams. The structure of the continuous phase in cream soaps changed from lamellar gel to a micellar aqueous solution upon the addition of water. This structural change during the washing process is important in producing the foaming activity of acid soaps to wash away dirt or excess fats from the skin surface. PMID:24671023

  11. Crystal structure of substrate free form of glycerol dehydratase

    SciTech Connect

    Liao, Der-Ing; Dotson, Garry; Turner, Jr., Ivan; Reiss, Lisa; Emptage, Mark

    2010-03-08

    Glycerol dehydratase (GDH) and diol dehydratase (DDH) are highly homologous isofunctional enzymes that catalyze the elimination of water from glycerol and 1,2-propanediol (1,2-PD) to the corresponding aldehyde via a coenzyme B{sub 12}-dependent radical mechanism. The crystal structure of substrate free form of GDH in complex with cobalamin and K{sup +} has been determined at 2.5 {angstrom} resolution. Its overall fold and the subunit assembly closely resemble those of DDH. Comparison of this structure and the DDH structure, available only in substrate bound form, shows the expected change of the coordination of the essential K{sup +} from hexacoordinate to heptacoordinate with the displacement of a single coordinated water by the substrate diol. In addition, there appears to be an increase in the rigidity of the K{sup +} coordination (as measured by lower B values) upon the binding of the substrate. Structural analysis of the locations of conserved residues among various GDH and DDH sequences has aided in identification of residues potentially important for substrate preference or specificity of protein-protein interactions.

  12. Diphytanyl glycerol ether distributions in sediments of the Orca Basin

    SciTech Connect

    Pease, T.K.; VanVleet, E.S.; Barre, J.S. )

    1992-09-01

    Archaebacterially produced diphytanyl glycerol ether (DPGE) was examined in core sediments from the Orca Basin, an anoxic hypersaline basin in the northwestern Gulf of Mexico, to observe its spatial variability and potential origin. A differential extraction protocol was employed to quantify the isopranyl glycerol ethers associated with unbound, intermediate-bound, and kerogen-bound lipid fractions. Archaebacterial lipids were evident at all depths for the unbound and intermediate-bound fractions. Concentrations of DPGE ranged from 0.51 to 2.91 [mu]g/g dry sediment at the surface and showed secondary maxima deeper in basin sediments. Intermediate-bound DPGE concentrations exhibited an inverse relationship to unbound DPGE concentrations. Kerogen-bound DPGE concentrations were normally below detection limits. Earlier studies describing the general homogeneity of lipid components within the overlying brine and at the brine/seawater interface suggest that the large-scale sedimentary DPGE variations observed in this study result from spatial and temporal variations in in-situ production by methanogenic or extremely halophilic archaebacteria.

  13. Diphytanyl glycerol ether distributions in sediments of the Orca Basin

    NASA Astrophysics Data System (ADS)

    Pease, Tamara K.; Van Vleet, Edward S.; Barre, Jill S.

    1992-09-01

    Archaebacterially produced diphytanyl glycerol ether (DPGE) was examined in core sediments from the Orca Basin, an anoxic hypersaline basin in the northwestern Gulf of Mexico, to observe its spatial variability and potential origin. A differential extraction protocol was employed to quantify the isopranyl glycerol ethers associated with unbound, intermediate-bound, and kerogen-bound lipid fractions. Archaebacterial lipids were evident at all depths for the unbound and intermediate-bound fractions. Concentrations of DPGE ranged from 0.51 to 2.91 μg/g dry sediment at the surface and showed secondary maxima deeper in basin sediments. Intermediate-bound DPGE concentrations exhibited an inverse relationship to unbound DPGE concentrations. Kerogen-bound DPGE concentrations were normally below detection limits. Earlier studies describing the general homogeneity of lipid components within the overlying brine and at the brine/seawater interface suggest that the large-scale sedimentary DPGE variations observed in this study result from spatial and temporal variations in in situ production by methanogenic or extremely halophilic archaebacteria.

  14. Dynamical and orientational structural crossovers in low-temperature glycerol.

    PubMed

    Seyedi, Salman; Martin, Daniel R; Matyushov, Dmitry V

    2016-07-01

    Mean-square displacements of hydrogen atoms in glass-forming materials and proteins, as reported by incoherent elastic neutron scattering, show kinks in their temperature dependence. This crossover, known as the dynamical transition, connects two approximately linear regimes. It is often assigned to the dynamical freezing of subsets of molecular modes at the point of equality between their corresponding relaxation times and the instrumental observation window. The origin of the dynamical transition in glass-forming glycerol is studied here by extensive molecular dynamics simulations. We find the dynamical transition to occur for both the center-of-mass translations and the molecular rotations at the same temperature, insensitive to changes of the observation window. Both the translational and rotational dynamics of glycerol show a dynamic crossover from the structural to a secondary relaxation at the temperature of the dynamical transition. A significant and discontinuous increase in the orientational Kirkwood factor and in the dielectric constant is observed in the same range of temperatures. No indication is found of a true thermodynamic transition to an ordered low-temperature phase. We therefore suggest that all observed crossovers are dynamic in character. The increase in the dielectric constant is related to the dynamic freezing of dipolar domains on the time scale of simulations. PMID:27575188

  15. Theoretical studies on the unimolecular decomposition of propanediols and glycerol.

    PubMed

    Ye, Lili; Zhang, Feng; Zhang, Lidong; Qi, Fei

    2012-05-10

    Polyols, a typical type of alcohol containing multiple hydroxyl groups, are being regarded as a new generation of a green energy platform. In this paper, the decomposition mechanisms for three polyol molecules, i.e., 1,2-propanediol, 1,3-propanediol, and glycerol, have been investigated by quantum chemistry calculations. The potential energy surfaces of propanediols and glycerol have been built by the QCISD(T) and CBS-QB3 methods, respectively. For the three molecules studied, the H(2)O-elimination and C-C bond dissociation reactions show great importance among all of the unimolecular decomposition channels. Rate constant calculations further demonstrate that the H(2)O-elimination reactions are predominant at low temperature and pressure, whereas the direct C-C bond dissociation reactions prevail at high temperature and pressure. The temperature and pressure dependence of calculated rate constants was demonstrated by the fitted Arrhenius equations. This work aims to better understand the thermal decomposition process of polyols and provide useful thermochemical and kinetic data for kinetic modeling of polyols-derived fuel combustion. PMID:22515339

  16. Hydrogen production by sorption-enhanced steam reforming of glycerol.

    PubMed

    Dou, Binlin; Dupont, Valerie; Rickett, Gavin; Blakeman, Neil; Williams, Paul T; Chen, Haisheng; Ding, Yulong; Ghadiri, Mojtaba

    2009-07-01

    Catalytic steam reforming of glycerol for H(2) production has been evaluated experimentally in a continuous flow fixed-bed reactor. The experiments were carried out under atmospheric pressure within a temperature range of 400-700 degrees C. A commercial Ni-based catalyst and a dolomite sorbent were used for the steam reforming reactions and in situ CO(2) removal. The product gases were measured by on-line gas analysers. The results show that H(2) productivity is greatly increased with increasing temperature and the formation of methane by-product becomes negligible above 500 degrees C. The results suggest an optimal temperature of approximately 500 degrees C for the glycerol steam reforming with in situ CO(2) removal using calcined dolomite as the sorbent, at which the CO(2) breakthrough time is longest and the H(2) purity is highest. The shrinking core model and the 1D-diffusion model describe well the CO(2) removal under the conditions of this work. PMID:19318245

  17. Diphytanyl glycerol ether distributions in sediments of the Orca Basin.

    PubMed

    Pease, T K; Van Vleet, E S; Barre, J S

    1992-09-01

    Archaebacterially produced diphytanyl glycerol ether (DPGE) was examined in core sediments from the Orca Basin, an anoxic hypersaline basin in the northwestern Gulf of Mexico, to observe its spatial variability and potential origin. A differential extraction protocol was employed to quantify the isopranyl glycerol ethers associated with unbound, intermediate-bound, and kerogen-bound lipid fractions. Archaebacterial lipids were evident at all depths for the unbound and intermediate-bound fractions. Concentrations of DPGE ranged from 0.51 to 2.91 micrograms/g dry sediment at the surface and showed secondary maxima deeper in basin sediments. Intermediate-bound DPGE concentrations exhibited an inverse relationship to unbound DPGE concentrations. Kerogen-bound DPGE concentrations were normally below detection limits. Earlier studies describing the general homogeneity of lipid components within the overlying brine and at the brine/seawater interface suggest that the large-scale sedimentary DPGE variations observed in this study result from spatial and temporal variations in in situ production by methanogenic or extremely halophilic archaebacteria. PMID:11540108

  18. Microfluidic Devices for the Measurement of Cellular Secretion

    NASA Astrophysics Data System (ADS)

    Schrell, Adrian M.; Mukhitov, Nikita; Yi, Lian; Wang, Xue; Roper, Michael G.

    2016-06-01

    The release of chemical information from cells and tissues holds the key to understanding cellular behavior and dysfunction. The development of methodologies that can measure cellular secretion in a time-dependent fashion is therefore essential. Often these measurements are made difficult by the high-salt conditions of the cellular environment, the presence of numerous other secreted factors, and the small mass samples that are produced when frequent sampling is used to resolve secretory dynamics. In this review, the methods that we have developed for measuring hormone release from islets of Langerhans are dissected to illustrate the practical difficulties of studying cellular secretions. Other methods from the literature are presented that provide alternative approaches to particularly challenging areas of monitoring cellular secretion. The examples presented in this review serve as case studies and should be adaptable to other cell types and systems for unique applications.

  19. Regulation of biliary lipid secretion by mdr2 P-glycoprotein in the mouse.

    PubMed Central

    Oude Elferink, R P; Ottenhoff, R; van Wijland, M; Smit, J J; Schinkel, A H; Groen, A K

    1995-01-01

    Disruption of the mdr2 gene in mice leads to a complete absence of phospholipid from bile (Smit, J. J. M., et al. 1993. Cell. 75:451-462). We have investigated the control of both mdr2 P-glycoprotein (Pgp) expression and bile salt secretion on biliary lipid secretion in the mouse. Lipid secretion was monitored at various bile salt output rates in wild-type mice (+/+), heterozygotes (+/-), and homozygotes (-/-) for mdr2 gene disruption. In (-/-) mice, phospholipid secretion was negligible at all bile salt output rates. In (+/-) mice, a curvilinear relation between bile salt and phospholipid secretion was observed similar to that in (+/+) mice; however, at all bile salt secretion rates phospholipid secretion was reduced compared to (+/+) mice, indicating that mdr2 Pgp exerts a strong control over secretion. Infusion of increasing amounts of taurocholate up to maximal secretory rate led to a decline in the phospholipid and cholesterol secretion in both (+/+) and (+/-) mice in accordance to what has been observed in other species. In contrast, in (-/-) mice cholesterol secretion increased under these conditions while phospholipid output remained extremely low. The increased cholesterol secretion may represent extraction of cholesterol from the canalicular plasma membrane by taurocholate micelles as opposed to the concomitant secretion of both phospholipid and cholesterol in the presence of a functional mdr2 Pgp. Increased bile flow in (-/-) mice could be attributed completely to an increase in the bile salt-independent fraction and may therefore be caused by the bile duct proliferation in these mice. Images PMID:7814632

  20. Glass polymorphism in glycerol-water mixtures: II. Experimental studies.

    PubMed

    Bachler, Johannes; Fuentes-Landete, Violeta; Jahn, David A; Wong, Jessina; Giovambattista, Nicolas; Loerting, Thomas

    2016-04-20

    We report a detailed experimental study of (i) pressure-induced transformations in glycerol-water mixtures at T = 77 K and P = 0-1.8 GPa, and (ii) heating-induced transformations of glycerol-water mixtures recovered at 1 atm and T = 77 K. Our samples are prepared by cooling the solutions at ambient pressure at various cooling rates (100 K s(-1)-10 K h(-1)) and for the whole range of glycerol mole fractions, χg. Depending on concentration and cooling rates, cooling leads to samples containing amorphous ice (χg ≥ 0.20), ice (χg ≤ 0.32), and/or "distorted ice" (0 < χg ≤ 0.38). Upon compression, we find that (a) fully vitrified samples at χg ≥ 0.20 do not show glass polymorphism, in agreement with previous works; (b) samples containing ice show pressure-induced amorphization (PIA) leading to the formation of high-density amorphous ice (HDA). PIA of ice domains within the glycerol-water mixtures is shown to be possible only up to χg ≈ 0.32 (T = 77 K). This is rather surprising since it has been known that at χg < 0.38, cooling leads to phase-separated samples with ice and maximally freeze-concentrated solution of χg ≈ 0.38. Accordingly, in the range 0.32 < χg < 0.38, we suggest that the water domains freeze into an interfacial ice, i.e., a highly-distorted form of layered ice, which is unable to transform to HDA upon compression. Upon heating samples recovered at 1 atm, we observe a rich phase behavior. Differential scanning calorimetry indicates that only at χg ≤ 0.15, the water domains within the sample exhibit polyamorphism, i.e., the HDA-to-LDA (low-density amorphous ice) transformation. At 0.15 < χg ≤ 0.38, samples contain ice, interfacial ice, and/or HDA domains. All samples (χg ≤ 0.38) show: the crystallization of amorphous ice domains, followed by the glass transition of the vitrified glycerol-water domains and, finally, the melting of ice at high temperatures. Our work exemplifies the complex "phase" behavior of glassy binary

  1. Metabolic Engineering of a Glycerol-Oxidative Pathway in Lactobacillus panis PM1 for Utilization of Bioethanol Thin Stillage: Potential To Produce Platform Chemicals from Glycerol

    PubMed Central

    Kang, Tae Sun; Korber, Darren R.

    2014-01-01

    Lactobacillus panis PM1 has the ability to produce 1,3-propanediol (1,3-PDO) from thin stillage (TS), which is the major waste material after bioethanol production, and is therefore of significance. However, the fact that L. panis PM1 cannot use glycerol as a sole carbon source presents a considerable problem in terms of utilization of this strain in a wide range of industrial applications. Accordingly, L. panis PM1 was genetically engineered to directly utilize TS as a fermentable substrate for the production of valuable platform chemicals without the need for exogenous nutrient supplementation (e.g., sugars and nitrogen sources). An artificial glycerol-oxidative pathway, comprised of glycerol facilitator, glycerol kinase, glycerol 3-phosphate dehydrogenase, triosephosphate isomerase, and NADPH-dependent aldehyde reductase genes of Escherichia coli, was introduced into L. panis PM1 in order to directly utilize glycerol for the production of energy for growth and value-added chemicals. A pH 6.5 culture converted glycerol to mainly lactic acid (85.43 mM), whereas a significant amount of 1,3-propanediol (59.96 mM) was formed at pH 7.5. Regardless of the pH, ethanol (82.16 to 83.22 mM) was produced from TS fermentations, confirming that the artificial pathway metabolized glycerol for energy production and converted it into lactic acid or 1,3-PDO and ethanol in a pH-dependent manner. This study demonstrates the cost-effective conversion of TS to value-added chemicals by the engineered PM1 strain cultured under industrial conditions. Thus, application of this strain or these research findings can contribute to reduced costs of bioethanol production. PMID:25281374

  2. Metabolic engineering of a glycerol-oxidative pathway in Lactobacillus panis PM1 for utilization of bioethanol thin stillage: potential to produce platform chemicals from glycerol.

    PubMed

    Kang, Tae Sun; Korber, Darren R; Tanaka, Takuji

    2014-12-01

    Lactobacillus panis PM1 has the ability to produce 1,3-propanediol (1,3-PDO) from thin stillage (TS), which is the major waste material after bioethanol production, and is therefore of significance. However, the fact that L. panis PM1 cannot use glycerol as a sole carbon source presents a considerable problem in terms of utilization of this strain in a wide range of industrial applications. Accordingly, L. panis PM1 was genetically engineered to directly utilize TS as a fermentable substrate for the production of valuable platform chemicals without the need for exogenous nutrient supplementation (e.g., sugars and nitrogen sources). An artificial glycerol-oxidative pathway, comprised of glycerol facilitator, glycerol kinase, glycerol 3-phosphate dehydrogenase, triosephosphate isomerase, and NADPH-dependent aldehyde reductase genes of Escherichia coli, was introduced into L. panis PM1 in order to directly utilize glycerol for the production of energy for growth and value-added chemicals. A pH 6.5 culture converted glycerol to mainly lactic acid (85.43 mM), whereas a significant amount of 1,3-propanediol (59.96 mM) was formed at pH 7.5. Regardless of the pH, ethanol (82.16 to 83.22 mM) was produced from TS fermentations, confirming that the artificial pathway metabolized glycerol for energy production and converted it into lactic acid or 1,3-PDO and ethanol in a pH-dependent manner. This study demonstrates the cost-effective conversion of TS to value-added chemicals by the engineered PM1 strain cultured under industrial conditions. Thus, application of this strain or these research findings can contribute to reduced costs of bioethanol production. PMID:25281374

  3. The Lewis-acid-catalyzed synthesis of hyperbranched poly(glycerol-diacid)s in toluene

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The first examples of monomeric glycerol-derived hyperbranched polyesters produced in a non-polar solvent system are reported here. The polymers were made by the Lewis acid (dibutyltin(IV)oxide)-catalyzed polycondensation of glycerol with either succinic acid (n (aliphatic chain length)=2), glutari...

  4. Degree of branching in hyperbranched poly(glycerol-co-diacid)s synthesized in toluene

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hyperbranched polymers were synthesized by using a Lewis acid (dibutyltin(IV)oxide) to catalyze the polycondensation of glycerol with either succinic acid (n (aliphatic chain length)=2), glutaric acid (n=3) or azelaic acid (n=7) in toluene. These are the first examples of diacid-glycerol hyperbranc...

  5. Utilization of Crude Glycerol as a Substrate for the Production of Rhamnolipid by Pseudomonas aeruginosa.

    PubMed

    Eraqi, Walaa A; Yassin, Aymen S; Ali, Amal E; Amin, Magdy A

    2016-01-01

    Biosurfactants are produced by bacteria or yeast utilizing different substrates as sugars, glycerol, or oils. They have important applications in the detergent, oil, and pharmaceutical industries. Glycerol is the product of biodiesel industry and the existing glycerol market cannot accommodate the excess amounts generated; consequently, new markets for refined glycerol need to be developed. The aim of present work is to optimize the production of microbial rhamnolipid using waste glycerol. We have developed a process for the production of rhamnolipid biosurfactants using glycerol as the sole carbon source by a local Pseudomonas aeruginosa isolate that was obtained from an extensive screening program. A factorial design was applied with the goal of optimizing the rhamnolipid production. The highest production yield was obtained after 2 days when cells were grown in minimal salt media at pH 6, containing 1% (v/v) glycerol and 2% (w/v) sodium nitrate as nitrogen source, at 37°C and at 180 rpm, and reached 2.164 g/L after 54 hours (0.04 g/L h). Analysis of the produced rhamnolipids by TLC, HPLC, and FTIR confirmed the nature of the biosurfactant as monorhamnolipid. Glycerol can serve as a source for the production of rhamnolipid from microbial isolates providing a cheap and reliable substrate. PMID:26942014

  6. Co-digestion of sewage sludge with glycerol to boost biogas production.

    PubMed

    Fountoulakis, M S; Petousi, I; Manios, T

    2010-10-01

    The feasibility of adding crude glycerol from the biodiesel industry to the anaerobic digesters treating sewage sludge in wastewater treatment plants was studied in both batch and continuous experiments at 35 degrees C. Glycerol addition can boost biogas yields, if it does not exceed a limiting 1% (v/v) concentration in the feed. Any further increase of glycerol causes a high imbalance in the anaerobic digestion process. The reactor treating the sewage sludge produced 1106+/-36 ml CH(4)/d before the addition of glycerol and 2353+/-94 ml CH(4)/d after the addition of glycerol (1% v/v in the feed). The extra glycerol-COD added to the feed did not have a negative effect on reactor performance, but seemed to increase the active biomass (volatile solids) concentration in the system. Batch kinetic experiments showed that the maximum specific utilization rate (mu(max)) and the saturation constant (K(S)) of glycerol were 0.149+/-0.015 h(-1) and 0.276+/-0.095 g/l, respectively. Comparing the estimated values with the kinetics constants for propionate reported in the literature, it can be concluded that glycerol uptake is not the rate-limiting step during the process. PMID:20434322

  7. Respiratory glycerol metabolism of Actinobacillus succinogenes 130Z for succinate production.

    PubMed

    Schindler, Bryan D; Joshi, Rajasi V; Vieille, Claire

    2014-09-01

    Actinobacillus succinogenes 130Z naturally produces among the highest levels of succinate from a variety of inexpensive carbon substrates. A few studies have demonstrated that A. succinogenes can anaerobically metabolize glycerol, a waste product of biodiesel manufacture and an inexpensive feedstock, to produce high yields of succinate. However, all these studies were performed in the presence of yeast extract, which largely removes the redox constraints associated with fermenting glycerol, a highly reduced molecule. We demonstrated that A. succinogenes cannot ferment glycerol in minimal medium, but that it can metabolize glycerol by aerobic or anaerobic respiration. These results were expected based on the A. succinogenes genome, which encodes respiratory enzymes, but no pathway for 1,3-propanediol production. We investigated A. succinogenes's glycerol metabolism in minimal medium in a variety of respiratory conditions by comparing growth, metabolite production, and in vitro activity of terminal oxidoreductases. Nitrate inhibited succinate production by inhibiting fumarate reductase expression. In contrast, growth in the presence of dimethylsulfoxide and in microaerobic conditions allowed high succinate yields. The highest succinate yield was 0.75 mol/mol glycerol (75 % of the maximum theoretical yield) in continuous microaerobic cultures. A. succinogenes could also grow and produce succinate on partially refined glycerols obtained directly from biodiesel manufacture. Finally, by expressing a heterologous 1,3-propanediol synthesis pathway in A. succinogenes, we provide the first proof of concept that A. succinogenes can be engineered to grow fermentatively on glycerol. PMID:25047181

  8. Production of 3-hydroxypropionic acid from glycerol by recombinant Pseudomonas denitrificans.

    PubMed

    Zhou, Shengfang; Catherine, Christy; Rathnasingh, Chelladurai; Somasundar, Ashok; Park, Sunghoon

    2013-12-01

    3-Hydroxypropionic acid (3-HP) can be produced from glycerol through two sequential enzymatic reactions that are catalyzed by a coenzyme B12 -dependent glycerol dehydratase and an NAD(P)(+) -dependent aldehyde dehydrogenase (ALDH), respectively. Pseudomonas denitrificans synthesizes coenzyme B12 under aerobic conditions, where NAD(P)(+) is regenerated efficiently. Hence, it is considered an ideal host for the production of 3-HP from glycerol under aerobic conditions. In this study, recombinant strains of P. denitrificans were developed and their potential for the production of 3-HP from glycerol was evaluated. When the enzymes, glycerol dehydratase (DhaB) and glycerol dehydratase reactivase (GdrAB), of Klebsiella pneumoniae were expressed heterologously, P. denitrificans could produce 3-HP at 37.7 mmol/L with 62% (mol/mol) yield on glycerol. Glucose was required as the carbon and energy sources for cell growth. The overexpression of heterologous ALDH was not essential; however, the titer and yield of 3-HP were improved to 54.7 mmol/L and 67% (mol/mol), respectively, when an ALDH gene (puuC) from K. pneumoniae was overexpressed. One serious drawback hindering the use of P. denitrificans as a recombinant host for 3-HP production is that it oxidizes 3-HP to malonate and utilizes 3-HP as a carbon source for growth. This is the first report on the development and use of recombinant P. denitrificans for 3-HP production from glycerol. PMID:23775313

  9. Co-digestion of sewage sludge with glycerol to boost biogas production

    SciTech Connect

    Fountoulakis, M.S.; Petousi, I.; Manios, T.

    2010-10-15

    The feasibility of adding crude glycerol from the biodiesel industry to the anaerobic digesters treating sewage sludge in wastewater treatment plants was studied in both batch and continuous experiments at 35 {sup o}C. Glycerol addition can boost biogas yields, if it does not exceed a limiting 1% (v/v) concentration in the feed. Any further increase of glycerol causes a high imbalance in the anaerobic digestion process. The reactor treating the sewage sludge produced 1106 {+-} 36 ml CH{sub 4}/d before the addition of glycerol and 2353 {+-} 94 ml CH{sub 4}/d after the addition of glycerol (1% v/v in the feed). The extra glycerol-COD added to the feed did not have a negative effect on reactor performance, but seemed to increase the active biomass (volatile solids) concentration in the system. Batch kinetic experiments showed that the maximum specific utilization rate ({mu}{sub max}) and the saturation constant (K{sub S}) of glycerol were 0.149 {+-} 0.015 h{sup -1} and 0.276 {+-} 0.095 g/l, respectively. Comparing the estimated values with the kinetics constants for propionate reported in the literature, it can be concluded that glycerol uptake is not the rate-limiting step during the process.

  10. Synthesis of biodiesel fuel additives from glycerol using green chemistry and supercritical fluids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For every 3 moles of fatty acid esters produced, 1 mole of glycerol remains, ~11% of the biodiesel volume. One new method of glycerol use could be as a biodiesel fuel additive/extender using eco-friendly heterogeneous catalysts and supercritical fluids (SFs). SFs have advantages such as greater diff...

  11. Green synthesis of noble nanometals (Au, Pt, Pd) using glycerol under microwave irradiation conditions

    EPA Science Inventory

    A newer application of glycerol in the field of nanomaterials synthesis has been developed from both the economic and environmental points of view. Glycerol can act as a reducing agent for the fabrication of noble nanometals, such as Au, Pt, and Pd, under microwave irradiation. T...

  12. Biodegradable Composites Based on Starch/EVOH/Glycerol Blends and Coconut Fibers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Unripe coconut fibers were used as fillers in a biodegradable polymer matrix of starch/Ethylene vinyl alcohol (EVOH)/glycerol. The effects of fiber content on the mechanical, thermal and structural properties were evaluated. The addition of coconut fiber into starch/EVOH/glycerol blends reduced the ...

  13. Glycerol Tri-Ester Derivatives as Diluents to Improve Low Temperature Properties of Vegetable Oils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Large-scale production of biodiesel has led to a surplus of glycerol, so new commercial uses of this co-product are being sought. Twenty four vegetable oils were screened using glycerol tris (2-ethylhexanoate) [GTEH] as a diluent to improve the low temperature properties. Epoxidized soybean oil (E...

  14. Glycerol Tri-Ester Derivatives as Diluent to Improve Low Temperature Properties of Vegetable Oils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Large-scale production of biodiesel has led to a surplus of glycerol, so new commercial uses of this co-product are under development. Increased utilization of glycerol would help biodiesel producers to become more competitive and viable. Lubricants based on vegetable oils generally suffer from po...

  15. Microstructure and molecular interaction in glycerol plasticized chitosan/poly(vinyl alcohol) blending films

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Poly (vinyl alcohol) (PVA)/chitosan (CS) blended films plasticized by glycerol were investigated using mechanical testing, atomic force microscopy (AFM), differential scanning calorimetry (DSC) and FTIR spectroscopy, with primary emphasis on the effects of the glycerol content and the molecular weig...

  16. Evaluation of Glycerol from Biodiesel Production as a Feed Ingredient for Channel Catfish, Ictalurus punctatus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glycerol is the main by-product of biodiesel production from vegetable oils and animal fats. It has been evaluated as an energy source for several farm animals. A study was conducted to examine the effects of various levels of glycerol in channel catfish, Ictalurus punctatus, diets. Fish with mean i...

  17. Utilization of Crude Glycerol as a Substrate for the Production of Rhamnolipid by Pseudomonas aeruginosa

    PubMed Central

    Eraqi, Walaa A.; Yassin, Aymen S.; Ali, Amal E.; Amin, Magdy A.

    2016-01-01

    Biosurfactants are produced by bacteria or yeast utilizing different substrates as sugars, glycerol, or oils. They have important applications in the detergent, oil, and pharmaceutical industries. Glycerol is the product of biodiesel industry and the existing glycerol market cannot accommodate the excess amounts generated; consequently, new markets for refined glycerol need to be developed. The aim of present work is to optimize the production of microbial rhamnolipid using waste glycerol. We have developed a process for the production of rhamnolipid biosurfactants using glycerol as the sole carbon source by a local Pseudomonas aeruginosa isolate that was obtained from an extensive screening program. A factorial design was applied with the goal of optimizing the rhamnolipid production. The highest production yield was obtained after 2 days when cells were grown in minimal salt media at pH 6, containing 1% (v/v) glycerol and 2% (w/v) sodium nitrate as nitrogen source, at 37°C and at 180 rpm, and reached 2.164 g/L after 54 hours (0.04 g/L h). Analysis of the produced rhamnolipids by TLC, HPLC, and FTIR confirmed the nature of the biosurfactant as monorhamnolipid. Glycerol can serve as a source for the production of rhamnolipid from microbial isolates providing a cheap and reliable substrate. PMID:26942014

  18. 21 CFR 172.850 - Lactylated fatty acid esters of glycerol and propylene glycol.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...) The additive meets the following specifications: Water insoluble combined lactic acid, 14-18 percent... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Lactylated fatty acid esters of glycerol and... CONSUMPTION Multipurpose Additives § 172.850 Lactylated fatty acid esters of glycerol and propylene...

  19. REGIOSPECIFIC ANALYSIS OF DIRICINOLEOYL-ACYL-GLYCEROL IN CASTOR OIL USING ELECTROSPRAY IONIZATION-MASS SPECTROMETRY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    HPLC fractions of castor oil were used to identify the regiospecific location of non-hydroxyl fatty acids on glycerol backbone in diricinoleoyl-acyl-glycerols using electrospray ionization MS3 of lithium adducts. The regiospecific ions in MS3 spectra were from the loss of 'a,B'-unsaturated fatty aci...

  20. Glycerol Affects Root Development through Regulation of Multiple Pathways in Arabidopsis

    PubMed Central

    Hu, Jun; Zhang, Yonghong; Wang, Jinfang; Zhou, Yongming

    2014-01-01

    Glycerol metabolism has been well studied biochemically. However, the means by which glycerol functions in plant development is not well understood. This study aimed to investigate the mechanism underlying the effects of glycerol on root development in Arabidopsis thaliana. Exogenous glycerol inhibited primary root growth and altered lateral root development in wild-type plants. These phenotypes appeared concurrently with increased endogenous glycerol-3-phosphate (G3P) and H2O2 contents in seedlings, and decreased phosphate levels in roots. Upon glycerol treatment, G3P level and root development did not change in glycerol kinase mutant gli1, but G3P level increased in gpdhc1 and fad-gpdh mutants, which resulted in more severely impaired root development. Overexpression of the FAD-GPDH gene attenuated the alterations in G3P, phosphate and H2O2 levels, leading to increased tolerance to exogenous glycerol, which suggested that FAD-GPDH plays an important role in modulating this response. Free indole-3-acetic acid (IAA) content increased by 46%, and DR5pro::GUS staining increased in the stele cells of the root meristem under glycerol treatment, suggesting that glycerol likely alters normal auxin distribution. Decreases in PIN1 and PIN7 expression, β-glucuronidase (GUS) staining in plants expressing PIN7pro::GUS and green fluorescent protein (GFP) fluorescence in plants expressing PIN7pro::PIN7-GFP were observed, indicating that polar auxin transport in the root was downregulated under glycerol treatment. Analyses with auxin-related mutants showed that TIR1 and ARF7 were involved in regulating root growth under glycerol treatment. Glycerol-treated plants showed significant reductions in root meristem size and cell number as revealed by CYCB1;1pro::GUS staining. Furthermore, the expression of CDKA and CYCB1 decreased significantly in treated plants compared with control plants, implying possible alterations in cell cycle progression. Our data demonstrated that glycerol

  1. Glycerol affects root development through regulation of multiple pathways in Arabidopsis.

    PubMed

    Hu, Jun; Zhang, Yonghong; Wang, Jinfang; Zhou, Yongming

    2014-01-01

    Glycerol metabolism has been well studied biochemically. However, the means by which glycerol functions in plant development is not well understood. This study aimed to investigate the mechanism underlying the effects of glycerol on root development in Arabidopsis thaliana. Exogenous glycerol inhibited primary root growth and altered lateral root development in wild-type plants. These phenotypes appeared concurrently with increased endogenous glycerol-3-phosphate (G3P) and H2O2 contents in seedlings, and decreased phosphate levels in roots. Upon glycerol treatment, G3P level and root development did not change in glycerol kinase mutant gli1, but G3P level increased in gpdhc1 and fad-gpdh mutants, which resulted in more severely impaired root development. Overexpression of the FAD-GPDH gene attenuated the alterations in G3P, phosphate and H2O2 levels, leading to increased tolerance to exogenous glycerol, which suggested that FAD-GPDH plays an important role in modulating this response. Free indole-3-acetic acid (IAA) content increased by 46%, and DR5pro::GUS staining increased in the stele cells of the root meristem under glycerol treatment, suggesting that glycerol likely alters normal auxin distribution. Decreases in PIN1 and PIN7 expression, β-glucuronidase (GUS) staining in plants expressing PIN7pro::GUS and green fluorescent protein (GFP) fluorescence in plants expressing PIN7pro::PIN7-GFP were observed, indicating that polar auxin transport in the root was downregulated under glycerol treatment. Analyses with auxin-related mutants showed that TIR1 and ARF7 were involved in regulating root growth under glycerol treatment. Glycerol-treated plants showed significant reductions in root meristem size and cell number as revealed by CYCB1;1pro::GUS staining. Furthermore, the expression of CDKA and CYCB1 decreased significantly in treated plants compared with control plants, implying possible alterations in cell cycle progression. Our data demonstrated that glycerol

  2. Activation of glycerol metabolism in Xanthomonas campestris by adaptive evolution to produce a high-transparency and low-viscosity xanthan gum from glycerol.

    PubMed

    Wang, Zichao; Wu, Jianrong; Zhu, Li; Zhan, Xiaobei

    2016-07-01

    Many studies have focused on using crude glycerol from biodiesel to obtain valuable products, but few of these studies have focused on obtaining polysaccharides. A mutant strain of Xanthomonas campestris CCTCC M2015714 that could use glycerol to produce high-transparency and low-viscosity xanthan gum was obtained by adaptive evolution, and the yield of xanthan gum reached 11.0g/L. We found that transcriptional levels of genes related to glycerol metabolism (glpF, glpK, glpD, and fbp) in the mutant strain were all higher than those from the parent strain. Using 5g/L sucrose or glucose as starter substrate, cell growth time decreased from 36h to 24h and xanthan gum yield increased. Moreover, the mutant strain can tolerate high titer glycerol, and its activity was not affected by the impurities in crude glycerol. All these results proved that crude glycerol from biodiesel industries can be used for xanthan gum production. PMID:27030959

  3. Distribution of Glycerol Diakyl Glycerol Tetraethers in Surface Soil and Crater Lake Sediments from Mount Kenya, East Africa

    NASA Astrophysics Data System (ADS)

    Omuombo, C.; Huguet, A.; Olago, D.; Williamson, D.

    2013-12-01

    Glycerol diakyl glycerol tetraethers (GDGTs), a palaeoclimate proxy based on the relative abundance of lipids produced by archaea and bacteria, is gaining wide acceptance for the determination of past temperature and pH conditions. This study looks at the spatial distribution and abundance of GDGTs in soil and sediment samples along an altitudinal transect from 3 crater lakes of Mt. Kenya (Lake Nkunga, Sacred Lake and Lake Rutundu) ranging in elevation from 1700m - 3080m above sea level. GDGTs were extracted with solvents and then analysed using high performance liquid chromatography/atmospheric pressure chemical ionization-mass spectrometry (HPLC/APCI-MS). Mean annual air temperature and pH were estimated based on the relative abundance of the different branched GDGTs, i.e. on the MBT (Methylation index of Branched Tetraethers) and CBT (Cyclization ratio of Branched Tetraethers) indices. Substantial amount of GDGTs were detected in both soil and sediment samples. In addition, branched GDGT distribution was observed to vary with altitude. These results highlight the importance of quantifying the branched GDGTs to understand the environmental parameters controlling the distribution of these lipids. The MBT/CBT proxy is a promising tool to infer palaeotemperatures and characterize the climate events of the past millennia in equatorial east Africa.

  4. Temperature and pH controls on glycerol dibiphytanyl glycerol tetraether lipid composition in the hyperthermophilic crenarchaeon Acidilobus sulfurireducens.

    PubMed

    Boyd, Eric S; Pearson, Ann; Pi, Yundan; Li, Wen-Jun; Zhang, Yi Ge; He, Liu; Zhang, Chuanlun L; Geesey, Gill G

    2011-01-01

    Cyclization in glycerol dibiphytanyl glycerol tetraethers (GDGTs) results in internal cyclopentane moieties which are believed to confer thermal stability to crenarchaeal membranes. While the average number of rings per GDGT lipid (ring index) is positively correlated with temperature in many temperate environments, poor correlations are often observed in geothermal environments, suggesting that additional parameters may influence GDGT core lipid composition in these systems. However, the physical and chemical parameters likely to influence GDGT cyclization which are often difficult to decouple in geothermal systems, making it challenging to assess their influence on lipid composition. In the present study, the influence of temperature (range 65-81°C), pH (range 3.0-5.0), and ionic strength (range 10.1-55.7 mM) on GDGT core lipid composition was examined in the hyperthermoacidophile Acidilobus sulfurireducens, a crenarchaeon originally isolated from a geothermal spring in Yellowstone National Park, Wyoming. When cultivated under defined laboratory conditions, the composition of individual and total GDGTs varied significantly with temperature and to a lesser extent with the pH of the growth medium. Ionic strength over the range of values tested did not influence GDGT composition. The GDGT core lipid ring index was positively correlated with temperature and negatively correlated with pH, suggesting that A. sulfurireducens responds to increasing temperature and acidity by increasing the number of cyclopentyl rings in GDGT core membrane lipids. PMID:21125411

  5. Enzymatic production of glycerol carbonate from by-product after biodiesel manufacturing process.

    PubMed

    Jung, Hongsub; Lee, Youngrak; Kim, Daeheum; Han, Sung Ok; Kim, Seung Wook; Lee, Jinwon; Kim, Yong Hwan; Park, Chulhwan

    2012-08-10

    Glycerol carbonate is one of the higher value-added products derived from glycerol. In this study, glycerol carbonate (GC) was synthesized by transesterification of glycerol and dimethyl carbonate (DMC) using Novozym 435 (Candida antarctica Lipase B) at various conditions. For the enzymatic production of GC, the optimum conditions were the amount of enzyme (75 g/L), DMC/glycerol molar ratio (2.00), reaction temperature (60°C) and organic solvent (acetonitrile). Experimental investigation of the effect of water content revealed that the conversion of GC was maximized with no added water. The addition of surfactant such as Tween 80 increased the GC conversion, which finally reached 96.25% under the optimum condition and with surfactant addition. PMID:22759533

  6. Salty glycerol versus salty water surface organization: bromide and iodide surface propensities.

    PubMed

    Huang, Zishuai; Hua, Wei; Verreault, Dominique; Allen, Heather C

    2013-07-25

    Salty NaBr and NaI glycerol solution interfaces are examined in the OH stretching region using broadband vibrational sum frequency generation (VSFG) spectroscopy. Raman and infrared (IR) spectroscopy are used to further understand the VSFG spectroscopic signature. The VSFG spectra of salty glycerol solutions reveal that bromide and iodide anions perturb the interfacial glycerol organization in a manner similar as that found in aqueous halide salt solutions, thus confirming the presence of bromide and iodide anions at the glycerol surface. Surface tension measurements are consistent with the surface propensity suggested by the VSFG data and also show that the surface excess increases with increasing salt concentration, similar to that of water. In addition, iodide is shown to have more surface prevalence than bromide, as has also been determined from aqueous solutions. These results suggest that glycerol behaves similarly to water with respect to surface activity and solvation of halide anions at its air/liquid interface. PMID:23663033

  7. Moisturizing Effects of Diglycerol Combined with Glycerol on Human Stratum Corneum.

    PubMed

    Tomiie, Ai; Shinozaki, Masami; Yamada, Takeshi; Kuriyama, Juhei

    2016-08-01

    The water content of the stratum corneum was measured to investigate the skin-moisturizing property of diglycerol in water and in a lotion. The water content of the stratum corneum, to which the diglycerol solution was applied, was lower than that of the glycerol solution for 8 h. However, skin treated with diglycerol in combination with glycerol solution maintained a higher capacitance level compared with that of glycerol solution alone after 8 h. Moreover, the long-term moisturizing effect of the stratum corneum prominently appeared when diglycerol was formulated to the lotion containing glycerol and 1,3-butylene glycol. These studies suggest that diglycerol in combination with glycerol has a long-term moisturizing effect on human skin. PMID:27430380

  8. Dietary glycerol for quail: association between productive performance and COX III mRNA expression.

    PubMed

    Silva, S C C; Gasparino, E; Batista, E; Tanamati, F; Vesco, A P D; Lala, B; de Oliveira, D P

    2016-01-01

    This study was carry out to evaluate mRNA expression of mitochondrial cytochrome c oxidase III in the Pectoralis superficialis muscle of 28-day-old quails fed diets containing 0, 8, and 12% glycerol. Total RNA was extracted (N = 10) and cDNA was amplified using specifics primers for qRT-PCR. Feed efficiency and feed intake were evaluated. COX III mRNA expression in breast muscle was higher in the group fed with 12% glycerol (0.863 AU); no differences were observed in the expression of this gene between the muscle of animals fed diets without glycerol (0.357 AU) and 8% glycerol (0.415 AU). Quails that showed greater COX III mRNA expression also showed the lowest feed efficiency. These results show that there is a difference in COX III mRNA expression in breast muscle of 28-day-old quail fed diets different concentrations of glycerol. PMID:27323091

  9. Microbial conversion of glycerol to 1,3-propanediol and related compounds

    SciTech Connect

    Cameron, D.C.; Held, A.M.; Zhu, Mei-Ying

    1995-12-01

    Glycerol is a co-product of the conversion of vegetable oils and animal fats to soap, fatty acids, fatty acid esters and biodiesel fuel. We have investigated the use of both native and recombinant microorganisms for the conversion of glycerol to more valuable products. Fed-batch fermentations of glycerol by Klebsiella pneumoniae gave over 50 g/L of 1,3-propanediol (1,3-PD, trimethylene glycol) with high volumetric productivity. Escherichia coli containing genes for glycerol dehydratase and 1,3-PD oxidoreductase from K. pneumoniae also gave 1,3-PD from glycerol, but at a lower level than the native organism. Experiments with the recombinant E. coli have provided insights into ways to improve 1,3-PD production in both the recombinant and native organism and to modify the pathway for the production of compounds such as 3-hydroxypropionaldehyde and dihydroxyacetone.

  10. Study Guide: Seven Simple Secrets

    ERIC Educational Resources Information Center

    Satterfield, Nancy; Breaux, Annette; Whitaker, Todd

    2007-01-01

    This study guide has been developed to accompany the "Seven Simple Secrets" book written by Dr. Todd Whitaker and Annette Breaux. "Seven Simple Secrets" focuses on those attributes that have been found to help teachers be their absolute best in their daily challenges of teaching and improving student learning. The study guide is divided into the…

  11. Guidelines for glycerol use in hyperhydration and rehydration associated with exercise.

    PubMed

    van Rosendal, Simon Piet; Osborne, Mark Andrew; Fassett, Robert Gordon; Coombes, Jeff Scott

    2010-02-01

    Dehydration in athletes alters cardiovascular and thermoregulatory function and may inhibit endurance exercise capacity if fluid loss exceeds 2% of bodyweight (BW). If this level of dehydration cannot be prevented when starting from a state of euhydration, then athletes may create a state of hyperhydration by consuming extra fluid prior to exercise. From this hyperhydrated situation, individuals have a greater capacity to tolerate fluid loss before becoming dehydrated. Furthermore, excess pre-exercise fluid intake enhances thermoregulatory ability, as well as increasing plasma volume to maintain cardiac output. However, hyperhydrating before exercise is difficult, because a large fluid intake is typically accompanied by diuresis. Glycerol-containing beverages create an osmotic gradient in the circulation favouring fluid retention, thereby facilitating hyperhydration and protecting against dehydration. Many studies have shown that increases in body water by 1 L or more are achievable through glycerol hyperhydration. This article analyses the evidence for glycerol use in facilitating hyperhydration and rehydration, and provides guidelines for athletes wishing to use this compound. An analysis of the studies in this area indicates that endurance athletes intending to hyperhydrate with glycerol should ingest glycerol 1.2 g/kg BW in 26 mL/kg BW of fluid over a period of 60 minutes, 30 minutes prior to exercise. The effects of glycerol on total body water when used during rehydration are less well defined, due to the limited studies conducted. However, ingesting glycerol 0.125 g/kg BW in a volume equal to 5 mL/kg BW during exercise will delay dehydration, while adding glycerol 1.0 g/kg BW to each 1.5 L of fluid consumed following exercise will accelerate the restoration of plasma volume. Side effects from glycerol ingestion are rare, but include nausea, gastrointestinal discomfort and light-headedness. In summary, glycerol ingestion before, during or following exercise

  12. Protein secretion in Bacillus species.

    PubMed Central

    Simonen, M; Palva, I

    1993-01-01

    Bacilli secrete numerous proteins into the environment. Many of the secretory proteins, their export signals, and their processing steps during secretion have been characterized in detail. In contrast, the molecular mechanisms of protein secretion have been relatively poorly characterized. However, several components of the protein secretion machinery have been identified and cloned recently, which is likely to lead to rapid expansion of the knowledge of the protein secretion mechanism in Bacillus species. Comparison of the presently known export components of Bacillus species with those of Escherichia coli suggests that the mechanism of protein translocation across the cytoplasmic membrane is conserved among gram-negative and gram-positive bacteria differences are found in steps preceding and following the translocation process. Many of the secretory proteins of bacilli are produced industrially, but several problems have been encountered in the production of Bacillus heterologous secretory proteins. In the final section we discuss these problems and point out some possibilities to overcome them. PMID:8464403

  13. Flow injection analysis-based methodology for automatic on-line monitoring and quality control for biodiesel production.

    PubMed

    Pinzi, S; Priego Capote, F; Ruiz Jiménez, J; Dorado, M P; Luque de Castro, M D

    2009-01-01

    An automated on-line approach based on determination of free and bound glycerol was here proposed to monitor biodiesel production. The method was based on liquid-liquid extraction of glycerol from the biodiesel to an aqueous ethanolic phase in which glycerol is oxidized to formaldehyde with meta periodate with subsequent reaction with acetylacetone. The reaction product was photometrically measured at 410 nm. Free and bound glycerol were differentiated by glycerides hydrolysis with potassium ethylate. The experimental set-up consisted of a flow-injection manifold for liquid-liquid extraction without phase separation and iterative change of the flow direction that enabled: (a) filling the flow manifold with a meta periodate-acetylacetone acceptor phase; (b) sampling of small amounts (microl) from the reactor; (c) determination of free glycerol by extraction from biodiesel to the aqueous phase with simultaneous oxidation-reaction with acetylacetone in the acceptor phase; (d) continuous monitoring of the aqueous phase by passage through a photometric detector; (e) filling the flow manifold with a potassium ethylate-meta periodate-acetylacetone new acceptor phase; (d) repetition of steps b-to-d to determine total glycerol after saponification of the bound glycerol by potassium ethylate; and (f) determination of bound glycerol by difference between the second and first analyses. The results showed that the proposed automated on-line method is a suitable option in routine analysis during biodiesel production. PMID:18614358

  14. Glycerol Ester Hydrolase Activity of Lactic Acid Bacteria

    PubMed Central

    Oterholm, Anders; Ordal, Z. John; Witter, Lloyd D.

    1968-01-01

    Seventeen strains of lactic acid bacteria were assayed for their glycerol ester hydrolase activity by using an improved agar-well technique, and eight strains by determining the activity in cell-free extracts using a pH-stat procedure. All cultures tested showed activity and hydrolyzed tributyrin more actively than they did tricaproin. The cell extract studies demonstrated that the cells contained intracellular esterases and lipases. The culture supernatant fluid was without activity. The lipase and the esterase differed in their relative activity to each other in the different extracts and in the ease by which they could be freed from the cellular debris. It is suggested that the lipase of these organisms is an endoenzyme and the esterase an ectoenzyme. PMID:5649866

  15. Secret key generation via a modified quantum secret sharing protocol

    NASA Astrophysics Data System (ADS)

    Smith, A. M.; Evans, P. G.; Lawrie, B.; Legré, M.; Lougovski, P.; Ray, W.; Williams, B. P.; Qi, B.; Grice, W. P.

    2015-05-01

    We present and experimentally show a novel protocol for distributing secret information between two and only two parties in a N-party single-qubit Quantum Secret Sharing (QSS) system. We demonstrate this new algorithm with N = 3 active parties over ~6km of telecom. fiber. Our experimental device is based on the Clavis2 Quantum Key Distribution (QKD) system built by ID Quantique but is generalizable to any implementation. We show that any two out of the N parties can build secret keys based on partial information from each other and with collaboration from the remaining N - 2 parties. This algorithm allows for the creation of two-party secret keys were standard QSS does not and significantly reduces the number of resources needed to implement QKD on a highly connected network such as the electrical grid.

  16. Secret Key Generation via a Modified Quantum Secret Sharing Protocol

    SciTech Connect

    Smith IV, Amos M; Evans, Philip G; Lawrie, Benjamin J; Legre, Matthieu; Lougovski, Pavel; Ray, William R; Williams, Brian P; Qi, Bing; Grice, Warren P

    2015-01-01

    We present and experimentally show a novel protocol for distributing secret information between two and only two parties in a N-party single-qubit Quantum Secret Sharing (QSS) system. We demonstrate this new algorithm with N = 3 active parties over 6km of telecom. ber. Our experimental device is based on the Clavis2 Quantum Key Distribution (QKD) system built by ID Quantique but is generalizable to any implementation. We show that any two out of the N parties can build secret keys based on partial information from each other and with collaboration from the remaining N > 2 parties. This algorithm allows for the creation of two-party secret keys were standard QSS does not and signicantly reduces the number of resources needed to implement QKD on a highly connected network such as the electrical grid.

  17. Effect of glycerol on ischemic cerebral edema assessed by magnetic resonance imaging.

    PubMed

    Sakamaki, Masanori; Igarashi, Hironaka; Nishiyama, Yutaka; Hagiwara, Hiroshi; Ando, Jun; Chishiki, Tetsurou; Curran, Brian C; Katayama, Yasuo

    2003-05-15

    The aim of this study is to assess the anticerebral edema effect of glycerol on a large cerebral infarction with magnetic resonance imaging (MRI). Glycerol, which is widely used as an osmotic agent against cerebral edema, could exacerbate brain tissue shift, since it has been suggested that glycerol might shrink a noninfarcted hemisphere and worsen the mass effect after a large hemispheric cerebral infarction. To investigate these issues, changes in a large hemispheric infarction with cerebral edema were studied using MRI before and after glycerol administration. Infarct volumes, normal brain tissue volumes and lateral ventricle volumes, in addition to signal intensities of T(2)-weighted images, were measured in six patients before and after administration of 300 ml of glycerol. Ventricle volumes were significantly increased (p=0.0015) and the T(2) signal intensity of the post-treatment ischemic region decreased after glycerol administration. In contrast, no significant differences in either cerebral volume or T(2) signal intensity were seen in the noninfarcted hemisphere before and after administration. Our data suggest that glycerol does not exacerbate the mass effect on a large hemispheric infarction. PMID:12686405

  18. Trehalose in glycerol-free freezing extender enhances post-thaw survival of boar spermatozoa

    PubMed Central

    ATHURUPANA, Rukmali; TAKAHASHI, Daisen; IOKI, Sumire; FUNAHASHI, Hiroaki

    2015-01-01

    Cryopreservation of boar semen is still considered suboptimal due to lower fertility as compared with fresh samples when glycerol, a permeating cryoprotectant, is used. Trehalose is a non-permeable cryoprotectant and nonreducing disaccharide known to stabilize proteins and biologic membranes. The aim of this study was to evaluate the cryosurvival and in vitro penetrability of boar spermatozoa when glycerol was replaced with trehalose in a freezing extender. Ejaculated Berkshire semen samples were diluted in egg yolk-based freezing extender containing glycerol (100 mM) or trehalose (0, 50, 100, 150, 200 and 250 mM) and cryopreserved using a straw freezing procedure. Thawed samples were analyzed for motility, viability, mitochondrial membrane potential (MMP), and acrosome integrity. In experiment 2, penetrability of spermatozoa cryopreserved with 100 mM glycerol or trehalose was examined. Replacement of cryoprotectant glycerol (100 mM) with trehalose had no effect on sperm viability, but replacing it with 100 mM trehalose improved motility, MMP and acrosome integrity significantly. Sperm motility and MMP were considerably higher in 100 mM trehalose, whereas the acrosome integrity was substantially higher in 100–250 mM trehalose. The in vitro penetration rate was also significantly higher in spermatozoa cryopreserved with trehalose (61.3%) than in those cryopreserved with glycerol (43.6%). In conclusion, 100 mM non-permeable trehalose can be used to replace glycerol, a permeating cryoprotectant, for maintenance of better post-thaw quality of boar spermatozoa. PMID:25754239

  19. Metabolic effects of glycerol supplementation and aerobic physical training on Wistar rats.

    PubMed

    Andrade, Eric Francelino; Lobato, Raquel Vieira; Araújo, Ticiana Vasques; Orlando, Débora Ribeiro; Gomes, Núbia Ferreira; Alvarenga, Renata Ribeiro; Rogatto, Gustavo Puggina; Zangeronimo, Márcio Gilberto; Pereira, Luciano José

    2014-09-01

    We evaluated the effects of oral glycerol supplementation on trained rats fed a normal diet. Wistar rats were distributed among 6 groups in a completely randomized 2 × 3 factorial design. The animals were subjected to 6 weeks of aerobic training. In the last 4 weeks, the animals' diet was supplemented with saline, glucose, or glycerol. Data were subjected to one-way analysis of variance (ANOVA) followed by a Student-Newmann-Keuls test, with values for P < 0.05 considered statistically significant. The change in body mass was lower in the trained groups, and their food and water consumption were higher. Glycerol supplementation resulted in an increase in the levels of triacylglycerol (TAG) and total cholesterol, as well as in the area and diameter of adipocytes. When associated with training, these parameters were similar to those of other trained groups. Levels of low-density lipoprotein + very-low-density lipoprotein cholesterol decreased in the trained animals that received glycerol compared with the non-trained ones. Glycerol consumption caused a reduction in food intake and increased the villous:crypt (V:C) ratio. No changes in glycemia, high density lipoproteins, or density of adipocytes were observed. Supplementation with glycerol together with aerobic physical training promoted beneficial metabolic effects. However, in non-trained rats glycerol increased the diameter and area of adipocytes, as well as the levels of TAG and total cholesterol. PMID:25105723

  20. Effect of water polyamorphism on the molecular vibrations of glycerol in its glassy aqueous solutions.

    PubMed

    Suzuki, Yoshiharu; Mishima, Osamu

    2016-07-14

    A glassy dilute glycerol-water solution undergoes a mutual polyamorphic transition relating to the transition between high- and low-density amorphous ices of solvent water. The polyamorphic transition behavior depends on the glycerol concentration, indicating that the glycerol affects the water polyamorphism. Here, we used the glassy dilute glycerol-water solution of the solute molar fraction of 0.07 and examined the effect of the polyamorphic change in solvent water on the molecular vibrations of glycerol via Raman spectroscopy. It is found that the molecular vibration of glycerol in high-density liquid like solvent water is different from that in the low-density liquid like solvent water and that the change in the molecular vibration of glycerol is synchronized with the polyamorphic transition of solvent water. The dynamical change of the solute molecule relates to the polyamorphic state of solvent water. This result suggests that the polyamorphic fluctuation of water structure emanated from the presumed liquid-liquid critical point plays an important role for the function of aqueous solution under an ambient condition such as the conformational stability of solute, the functional expression of solute, and so on. PMID:27421414

  1. Fermentation of glycerol into ethanol in a microbial electrolysis cell driven by a customized consortium.

    PubMed

    Speers, Allison M; Young, Jenna M; Reguera, Gemma

    2014-06-01

    The in situ generation of ethanol from glycerol-containing wastewater shows promise to improve the economics of the biodiesel industry. Consequently, we developed a microbial electrolysis cell (MEC) driven by the synergistic metabolisms of the exoelectrogen Geobacter sulfurreducens and the bacterium Clostridium cellobioparum, which fermented glycerol into ethanol in high yields (90%) and produced fermentative byproducts that served as electron donors for G. sulfurreducens. Syntrophic cooperation stimulated glycerol consumption, ethanol production, and the conversion of fermentation byproducts into cathodic H2 in the MEC. The platform was further improved by adaptively evolving glycerol-tolerant strains with robust growth at glycerol loadings typical of biodiesel wastewater and by increasing the buffering capacity of the anode medium. This resulted in additional increases in glycerol consumption (up to 50 g/L) and ethanol production (up to 10 g/L) at rates that greatly exceeded the capacity of the anode biofilms to concomitantly remove the fermentation byproducts. As a result, 1,3-propanediol was generated as a metabolic sink for electrons not converted into electricity syntrophically. The results highlight the potential of consortia to process glycerol in MECs and provide insights into genetic engineering and system design approaches that can be implemented to further improve MEC performance to satisfy industrial needs. PMID:24802954

  2. Hydrogenolysis of Glycerol to 1,2-Propanediol Over Clay Based Catalysts.

    PubMed

    Lee, Sang-Yong; Jung, Jae-Sun; Yang, Eun-Hyeok; Lee, Kwan-Young; Moon, Dong Ju

    2015-11-01

    1,2-propanediol (1,2-PDO) is one of the promising product among the valuable products derived from glycerol and it can be obtained by the catalytic hydrogenolysis of glycerol. Copper-supported clay-based catalysts were prepared with different pore sizes using various ratios of kaolin, Mg, and Al by coprecipitation and applied in the selective hydrogenolysis of glycerol to 1,2-PDO. In recent research, variations of pore volume and pore size could affect the diffusion of reagents within the catalyst due to the collision between reagents or pore wall and reagents. It changes selectivities of each product in hydrogenolysis of glycerol reaction. The physico-chemical properties of the catalysts were analyzed by XRD, N2 physisorption, TPR, CO2-TPD, SEM, and a mercury porosimeter. The Cu/TALCITE 4 catalyst showed 98% 1,2-PDO selectivity with 65% glycerol conversion under the optimized condition of 190 degrees C, 25 bar, and 20 wt% glycerol aqueous solution. It was found that the basic strength and meso-macro pore structure of the catalysts play an important role in glycerol conversion and 1,2-PDO selectivity. PMID:26726594

  3. Meta-analysis: Effects of glycerol administration on plasma volume, haemoglobin, and haematocrit.

    PubMed

    Koehler, Karsten; Thevis, Mario; Schaenzer, Wilhelm

    2013-01-01

    The use of glycerol in combination with excess fluid can be used to increase total body water. Because glycerol hyperhydration may also be misused to mask the effects of blood doping on doping-relevant parameters, namely haemoglobin and haematocrit, glycerol has been prohibited by the World Anti-Doping Agency since 2010. In order to test this rationale, the purpose of this meta-analysis was to quantify the effects of glycerol hyperhydration on plasma volume, haemoglobin, and haematocrit in comparison to administration of fluid only. Following a literature search, a total of seven studies was included and meta-analyses were performed separately for the effects on plasma volume (5 studies, total n = 54) and on haemoglobin (6 studies, n = 52) and haematocrit (6 studies, n = 52). The meta-analysis revealed that the increase in plasma volume was 3.3% larger (95%-CI: 1.1-5.5%) after glycerol administration when compared to fluid only. Reductions in haemoglobin were 0.2 g/dl (95%-CI: -0.3, 0.0) larger and there was no difference in the changes in haematocrit between glycerol and fluid administration (95%-CI: -0.7-0.8%). In comparison with other plasma-volume expanding agents, glycerol hyperhydration has a very limited potential in increasing plasma volume and altering doping-relevant blood parameters. PMID:24353192

  4. Effect of water polyamorphism on the molecular vibrations of glycerol in its glassy aqueous solutions

    NASA Astrophysics Data System (ADS)

    Suzuki, Yoshiharu; Mishima, Osamu

    2016-07-01

    A glassy dilute glycerol-water solution undergoes a mutual polyamorphic transition relating to the transition between high- and low-density amorphous ices of solvent water. The polyamorphic transition behavior depends on the glycerol concentration, indicating that the glycerol affects the water polyamorphism. Here, we used the glassy dilute glycerol-water solution of the solute molar fraction of 0.07 and examined the effect of the polyamorphic change in solvent water on the molecular vibrations of glycerol via Raman spectroscopy. It is found that the molecular vibration of glycerol in high-density liquid like solvent water is different from that in the low-density liquid like solvent water and that the change in the molecular vibration of glycerol is synchronized with the polyamorphic transition of solvent water. The dynamical change of the solute molecule relates to the polyamorphic state of solvent water. This result suggests that the polyamorphic fluctuation of water structure emanated from the presumed liquid-liquid critical point plays an important role for the function of aqueous solution under an ambient condition such as the conformational stability of solute, the functional expression of solute, and so on.

  5. Physiologic Mechanisms Involved in Accumulation of 3-Hydroxypropionaldehyde during Fermentation of Glycerol by Enterobacter agglomerans

    PubMed Central

    Barbirato, F.; Soucaille, P.; Bories, A.

    1996-01-01

    When grown in 700 mM glycerol within the pH range 6.0 to 7.5, anaerobic pH-regulated cultures of Enterobacter agglomerans exhibited an extracellular accumulation of 3-hydroxypropionaldehyde (3-HPA). This phenomenon, which causes fermentation cessation, occurred earlier when pH was low. In contrast, substrate consumption was complete at pH 8. Levels of glycerol-catabolizing enzymes, i.e., glycerol dehydrogenase and dihydroxyacetone kinase for the oxidative route and glycerol dehydratase and 1,3-propanediol dehydrogenase for the reductive route, as well as the nucleotide pools were determined periodically in the pH 7- and pH 8-regulated cultures. A NAD/NADH ratio of 1.7 was correlated with the beginning of the production of the inhibitory metabolite. Further accumulation was dependent on the ratio of glycerol dehydratase activity to 1,3-propanediol dehydrogenase activity. For a ratio higher than 1, 3-HPA was produced until fermentation ceased, which occurred for the pH 7-regulated culture. At pH 8, a value below 1 was noticed and 3-HPA accumulation was transient, while the NAD/NADH ratio decreased. The low rate of glycerol dissimilation following the appearance of 3-HPA in the culture medium was attributed to the strong inhibitory effect exerted by 3-HPA on glycerol dehydrogenase activity. PMID:16535461

  6. Comparison of Different Strategies for Selection/Adaptation of Mixed Microbial Cultures Able to Ferment Crude Glycerol Derived from Second-Generation Biodiesel

    PubMed Central

    Varrone, C.; Heggeset, T. M. B.; Le, S. B.; Haugen, T.; Markussen, S.; Skiadas, I. V.; Gavala, H. N.

    2015-01-01

    Objective of this study was the selection and adaptation of mixed microbial cultures (MMCs), able to ferment crude glycerol generated from animal fat-based biodiesel and produce building-blocks and green chemicals. Various adaptation strategies have been investigated for the enrichment of suitable and stable MMC, trying to overcome inhibition problems and enhance substrate degradation efficiency, as well as generation of soluble fermentation products. Repeated transfers in small batches and fed-batch conditions have been applied, comparing the use of different inoculum, growth media, and Kinetic Control. The adaptation of activated sludge inoculum was performed successfully and continued unhindered for several months. The best results showed a substrate degradation efficiency of almost 100% (about 10 g/L glycerol in 21 h) and different dominant metabolic products were obtained, depending on the selection strategy (mainly 1,3-propanediol, ethanol, or butyrate). On the other hand, anaerobic sludge exhibited inactivation after a few transfers. To circumvent this problem, fed-batch mode was used as an alternative adaptation strategy, which led to effective substrate degradation and high 1,3-propanediol and butyrate production. Changes in microbial composition were monitored by means of Next Generation Sequencing, revealing a dominance of glycerol consuming species, such as Clostridium, Klebsiella, and Escherichia. PMID:26509171

  7. Hydrophobic fractal surface from glycerol tripalmitate and the effects on C6 glioma cell growth.

    PubMed

    Zhang, Shanshan; Chen, Xuerui; Yu, Jing; Hong, Biyuan; Lei, Qunfang; Fang, Wenjun

    2016-06-01

    To provide a biomimic environment for glial cell culture, glycerol tripalmitate (PPP) has been used as a raw material to prepare fractal surfaces with different degrees of hydrophobicity. The spontaneous formation of the hydrophobic fractal surfaces was monitored by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The surface morphologies were observed by a scanning electron microscope (SEM), and then the fractal dimension (FD) values of the surfaces were determined with the box-counting method. C6 glioma cells were cultured and compared on different hydrophobic PPP surfaces and poly-L-lysine (PLL)-coated surface. The cell numbers as a function of incubation time on different surfaces during the cell proliferation process were measured, and the cell morphologies were observed under a fluorescence microscope. Influences of hydrophobic fractal surfaces on the cell number and morphology were analyzed. The experimental results show that the cell proliferation rates decrease while the cell morphology complexities increase with the growth of the fractal dimensions of the PPP surfaces. PMID:26970826

  8. Influence of water availability in the distributions of branched glycerol dialkyl glycerol tetraether in soils of the Iberian Peninsula

    NASA Astrophysics Data System (ADS)

    Menges, J.; Huguet, C.; Alcañiz, J. M.; Fietz, S.; Sachse, D.; Rosell-Melé, A.

    2014-05-01

    The combined application of the MBT (degree of methylation) and CBT (degree of cyclization) indices, based on the distribution of branched glycerol dialkyl glycerol tetraethers (brGDGTs) in soils, has been proposed as a paleoproxy to estimate mean annual temperature (MAT). CBT quantifies the degree of cyclization of brGDGTs and relates to soil pH. MBT and the simplified version MBT' quantify the degree of methylation of brGDGTs and relate to MAT and soil pH. However, other factors such as soil water availability have also been suggested to influence MBT' and possibly restrict the combined application of the MBT' and CBT indices as a paleotemperature proxy. To assess the effect of hydrological conditions on MBT' and CBT, a set of 23 Iberian Peninsula soil samples, covering a MAT range from 10 to 18 °C and a mean annual precipitation (MAP) range of 405 mm to 1455 mm, was analyzed. We found that the CBT was indeed significantly correlated with soil pH in our sample set. In contrast, MBT' was not correlated with MAT but had a significant correlation with the aridity index (AI), a parameter related to water availability in soils. The AI can explain 50% of the variation of the MBT', and 70% of the residuals of MAT estimated with the MBT/CBT proxy as compared to instrumentally measured MAT. We propose that, in arid settings, where water may be an ecologically limiting factor, MBT' is influenced by hydrological conditions rather than temperature. Thus, our results suggest that the combination of MBT' and CBT indices should be applied with caution in paleotemperature reconstructions in soils from dry subhumid to hyperarid environments.

  9. Evidence of moisture control on the methylation of branched glycerol dialkyl glycerol tetraethers in semi-arid and arid soils

    NASA Astrophysics Data System (ADS)

    Dang, Xinyue; Yang, Huan; Naafs, B. David A.; Pancost, Richard D.; Xie, Shucheng

    2016-09-01

    The distribution of bacterial branched glycerol dialkyl glycerol tetraethers (brGDGTs) is influenced by growth temperature and pH. This results in the widespread application of the brGDGT-based MBT(‧)/CBT proxy (MBT - methylation of branched tetraethers, CBT - cyclization of branched tetraethers) in terrestrial paleo-environmental reconstructions. Recently, it was shown that the amount of precipitation could also have an impact on CBT, as well as the abundance of brGDGTs relative to that of archaeal isoprenoidal (iso)GDGTs (Ri/b) and the absolute abundance of brGDGTs, potentially complicating the use of MBT/CBT as paleothermometer. However, the full influence of hydrology, and in particular soil water content (SWC), on GDGT distributions remains unclear. Here we investigated variations in the GDGT distribution across a SWC gradient (0-61%) around Qinghai Lake in the Tibetan Plateau, an arid to semiarid region in China. Our results demonstrate that SWC affects the brGDGT distribution. In particular, we show that SWC has a clear impact on the degree of methylation of C6-methylated brGDGTs, whereas C5-methylated brGDGTs are more impacted by temperature. This results in a combined SWC and temperature control on MBT‧. In this context we propose a diagnostic parameter, the IR6ME (relative abundance of C6-methylated GDGTs) index, to evaluate the applicability of brGDGT-based paleotemperature reconstructions. Using the global dataset, expanded with our own data, MBT‧ has a significant correlation with mean annual air temperature when IR6ME < 0.5, allowing for the use of MBT‧/CBT as temperature proxy. However, MBT‧ has a significant correlation with mean annual precipitation (i.e., a substantial reflection of SWC impact) when IR6ME > 0.5, implying that MBT‧ may respond to hydrological change in these regions and can be used as a proxy for MAP.

  10. Concentrations and abundance ratios of long-chain alkenones and glycerol dialkyl glycerol tetraethers in sinking particles south of Java

    NASA Astrophysics Data System (ADS)

    Chen, Wenwen; Mohtadi, Mahyar; Schefuß, Enno; Mollenhauer, Gesine

    2016-06-01

    In this study, we obtained concentrations and abundance ratios of long-chain alkenones and glycerol dialkyl glycerol tetraethers (GDGTs) in a one-year time-series of sinking particles collected with a sediment trap moored from December 2001 to November 2002 at 2200 m water depth south of Java in the eastern Indian Ocean. We investigate the seasonality of alkenone and GDGT fluxes as well as the potential habitat depth of the Thaumarchaeota producing the GDGTs entrained in sinking particles. The alkenone flux shows a pronounced seasonality and ranges from 1 μg m-2 d-1 to 35 μg m-2 d-1. The highest alkenone flux is observed in late September during the Southeast monsoon, coincident with high total organic carbon fluxes as well as high net primary productivity. Flux-weighted mean temperature for the high flux period using the alkenone-based sea-surface temperature (SST) index U37K‧ is 26.7 °C, which is similar to satellite-derived Southeast (SE) monsoon SST (26.4 °C). The GDGT flux displays a weaker seasonality than that of the alkenones. It is elevated during the SE monsoon period compared to the Northwest (NW) monsoon and intermonsoon periods (approximately 2.5 times), which is probably related to seasonal variation of the abundance of Thaumarchaeota, or to enhanced export of GDGTs by aggregation with sinking phytoplankton detritus. Flux-weighted mean temperature inferred from the GDGT-based TEX86H index is 26.2 °C, which is 1.8 °C lower than mean annual (ma) SST but similar to SE monsoon SST. As the time series of TEX86H temperature estimates, however, does not record a strong seasonal amplitude, we infer that TEX86H reflects ma upper thermocline temperature at approximately 50 m water depth.

  11. Branched glycerol dialkyl glycerol tetraethers in Arctic lake sediments: Sources and implications for paleothermometry at high latitudes

    NASA Astrophysics Data System (ADS)

    Peterse, Francien; Vonk, Jorien E.; Holmes, R. Max; Giosan, Liviu; Zimov, Nikita; Eglinton, Timothy I.

    2014-08-01

    Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are analyzed in different lakes of the Mackenzie (Canadian Arctic) and Kolyma (Siberian Arctic) River basins to evaluate their sources and the implications for brGDGT-based paleothermometry in high-latitude lakes. The comparison of brGDGT distributions and concentrations in the lakes with those in river suspended particulate matter, riverbank sediments, and permafrost material indicates that brGDGTs in Arctic lake sediments have mixed sources. In contrast to global observations, distributional offsets between brGDGTs in Arctic lakes and elsewhere in the catchment are minor, likely due to the extreme seasonality and short window of biological production at high latitudes. Consequently, both soil- and lake-calibrated brGDGT-based temperature proxies return sensible temperature estimates, even though the mean air temperature (MAT) in the Arctic is below the calibration range. The original soil-calibrated MBT-CBT (methylation of branched tetraethers-cyclisation of branched tetraethers) proxy generates MATs similar to those in the studied river basins, whereas using the recently revised MBT'-CBT calibration overestimates MAT. The application of the two global lake calibrations, generating summer air temperatures (SAT) and MAT, respectively, illustrates the influence of seasonality on the production of brGDGTs in lakes, as the latter overestimates actual MAT, whereas the SAT-based lake calibration accounts for this influence and consequently returns more accurate temperatures. Our results in principle support the application of brGDGT-based temperature proxies in high-latitude lakes in order to obtain long-term paleotemperature records for the Arctic, although the calibration and associated transfer function have to be selected with care.

  12. A population study of urine glycerol concentrations in elite athletes competing in North America.

    PubMed

    Kelly, Brian N; Madsen, Myke; Sharpe, Ken; Nair, Vinod; Eichner, Daniel

    2013-01-01

    Glycerol is an endogenous substance that is on the World Anti-Doping Agency's list of prohibited threshold substances due to its potential use as a plasma volume expansion agent. The WADA has set the threshold for urine glycerol, including measurement uncertainty, at 1.3 mg/mL. Glycerol in circulation largely comes from metabolism of triglycerides in order to meet energy requirements and when the renal threshold is eclipsed, glycerol is excreted into urine. In part due to ethnic differences in postprandial triglyceride concentrations, we investigated urine glycerol concentrations in a population of elite athletes competing in North America and compared the results to those of athletes competing in Europe. 959 urine samples from elite athletes competing in North America collected for anti-doping purposes were analyzed for urine glycerol concentrations by a gas chromatography mass-spectrometry method. Samples were divided into groups according to: Timing (in- or out-of-competition), Class (strength, game, or endurance sports) and Gender. 333 (34.7%) samples had undetectable amounts of glycerol (<1 μg/mL). 861 (89.8%) of the samples had glycerol concentrations ≤20 μg/mL. The highest glycerol concentration observed was 652 μg/mL. Analysis of the data finds the effects of each category to be statistically significant. The largest estimate of the 99.9(th) percentile, from the in-competition, female, strength athlete samples, was 1813 μg/mL with a 95% confidence range from 774 to 4251 μg/mL. This suggests a conservative threshold of 4.3 mg/mL, which would result in a reasonable detection window for urine samples collected in-competition for all genders and sport classes. PMID:24353191

  13. Development of bioelectrocatalytic activity stimulates mixed-culture reduction of glycerol in a bioelectrochemical system

    PubMed Central

    Zhou, Mi; Freguia, Stefano; Dennis, Paul G; Keller, Jürg; Rabaey, Korneel

    2015-01-01

    In a microbial bioelectrochemical system (BES), organic substrate such as glycerol can be reductively converted to 1,3-propanediol (1,3-PDO) by a mixed population biofilm growing on the cathode. Here, we show that 1,3-PDO yields positively correlated to the electrons supplied, increasing from 0.27 ± 0.13 to 0.57 ± 0.09 mol PDO mol−1 glycerol when the cathodic current switched from 1 A m−2 to 10 A m−2. Electrochemical measurements with linear sweep voltammetry (LSV) demonstrated that the biofilm was bioelectrocatalytically active and that the cathodic current was greatly enhanced only in the presence of both biofilm and glycerol, with an onset potential of −0.46 V. This indicates that glycerol or its degradation products effectively served as cathodic electron acceptor. During long-term operation (> 150 days), however, the yield decreased gradually to 0.13 ± 0.02 mol PDO mol−1 glycerol, and the current–product correlation disappeared. The onset potentials for cathodic current decreased to −0.58 V in the LSV tests at this stage, irrespective of the presence or absence of glycerol, with electrons from the cathode almost exclusively used for hydrogen evolution (accounted for 99.9% and 89.5% of the electrons transferred at glycerol and glycerol-free conditions respectively). Community analysis evidenced a decreasing relative abundance of Citrobacter in the biofilm, indicating a community succession leading to cathode independent processes relative to the glycerol. It is thus shown here that in processes where substrate conversion can occur independently of the electrode, electroactive microorganisms can be outcompeted and effectively disconnected from the substrate. PMID:25817314

  14. Multiple effects of glycerol on plant cell metabolism. Phosphorus-31 nuclear magnetic resonance studies.

    PubMed

    Aubert, S; Gout, E; Bligny, R; Douce, R

    1994-08-26

    The effects of glycerol on plant cell metabolism were studied with sycamore (Acer pseudoplatanus L.) cells using 31P nuclear magnetic resonance spectroscopy. After a long period of sucrose starvation, the addition of 50 mM glycerol to the medium did not restore the original glucose-6-P pool and led to a rapid accumulation of sn-glycerol-3-P in the cytoplasmic compartment. The synthesis of sn-glycerol-3-P was rapid and occurred first at the expense of cytoplasmic P(i). Accumulated sn-glycerol-3-P competitively inhibited glucose-6-phosphate isomerase activity when fructose-6-P was the varied substrate. Such a situation prevented the rapid recycling of triose phosphates back to hexose phosphates and led to an arrest of the functioning of the cytosolic and plastidial pentose phosphate pathways. Under these conditions, the flow of carbon to drive cell respiration derived almost exclusively from glycerol, and this polyalcohol was not used as a source of carbon skeletons for biosynthesis. Glycerol also induced the accumulation of O-phosphohomoserine in the cytoplasmic compartment as long as the cell culture medium contained sucrose. Finally glycerol added to sucrose-starved cells stopped the accumulation of phosphocholine (Roby, C., Martin J.-B., Bligny, R., and Douce, R. (1987) J. Biol. Chem. 262, 5000-5007) and prevented a further decline in the uncoupled rate of O2 consumption by the cells (Journet, E. P., Bligny, R., and Douce, R. (1986) J. Biol. Chem. 261, 3193-3199). These last observations strongly suggest that glycerol prevented the triggering of autophagy induced by sucrose starvation in sycamore cells. PMID:8063774

  15. Glycerolipid biosynthesis in Saccharomyces cerevisiae: sn-glycerol-3-phosphate and dihydroxyacetone phosphate acyltransferase activities.

    PubMed Central

    Schlossman, D M; Bell, R M

    1978-01-01

    Yeast acyl-coenzyme A:dihydroxyacetone-phosphate O-acyltransferase (DHAP acyltransferase; EC 2.3.1.42) was investigated to (i) determine whether its activity and that of acyl-coenzyme A:sn-glycerol-3-phosphate O-acyltransferase (glycerol-P acyltransferase; EC 2.3.1.15) represent dual catalytic functions of a single membranous enzyme, (ii) estimate the relative contributions of the glycerol-P and DHAP pathways for yeast glycerolipid synthesis, and (iii) evaluate the suitability of yeast for future genetic investigations of the eucaryotic glycerol-P and DHAP acyltransferase activities. The membranous DHAP acyltransferase activity showed an apparent Km of 0.79 mM for DHAP, with a Vmax of 5.3 nmol/min per mg, whereas the glycerol-P acyltransferase activity showed an apparent Km of 0.05 mM for glycerol-P, with a Vmax of 3.4 nmol/min per mg. Glycerol-P was a competitive inhibitor (Ki, 0.07 mM) of the DHAP acyltransferase activity, and DHAP was a competitive inhibitor (Ki, 0.91 mM) of the glycerol-P acyltransferase activity. The two acyltransferase activities exhibited marked similarities in their pH dependence, acyl-coenzyme A chain length preference and substrate concentration dependencies, thermolability, and patterns of inactivation by N-ethylmaleimide, trypsin, and detergents. Thus, the data strongly suggest that yeast glycerol-P and DHAP acyltransferase activities represent dual catalytic functions of a single membrane-bound enzyme. Furthermore, since no acyl-DHAP oxidoreductase activity could be detected in yeast membranes, the DHAP pathway for glycerolipid synthesis may not operate in yeast. PMID:25265

  16. Production of 1,3-propanediol by Klebsiella pneumoniae from glycerol broth.

    PubMed

    Cheng, Ke-Ke; Zhang, Jian-An; Liu, De-Hua; Sun, Yan; Yang, Ming-De; Xu, Jing-Ming

    2006-11-01

    Broth containing 152 g glycerol l(-1) from Candida krusei culture was converted to 1,3-propanediol by Klebsiella pneumoniae. Residual glucose in the broth promoted growth of K. pneumoniae while acetate was inhibitory. After desalination treatment of glycerol broth by electrodialysis, the acetate in the broth was removed. A fed-batch culture with electrodialytically pretreated broth as substrate was developed giving 53 g 1,3-propanediol l(-1) with a yield of 0.41 g g(-1) glycerol and a productivity of 0.94 g l(-1) h(-1). PMID:16912919

  17. Secret Public Key Protocols Revisited

    NASA Astrophysics Data System (ADS)

    Lim, Hoon Wei; Paterson, Kenneth G.

    Password-based protocols are important and popular means of providing human-to-machine authentication. The concept of secret public keys was proposed more than a decade ago as a means of securing password-based authentication protocols against off-line password guessing attacks, but was later found vulnerable to various attacks. In this paper, we revisit the concept and introduce the notion of identity-based secret public keys. Our new identity-based approach allows secret public keys to be constructed in a very natural way using arbitrary random strings, eliminating the structure found in, for example, RSA or ElGamal keys. We examine identity-based secret public key protocols and give informal security analyses, indicating that they are secure against off-line password guessing and other attacks.

  18. Crude glycerol as feedstock for the sustainable production of p-hydroxybenzoate by Pseudomonas putida S12.

    PubMed

    Verhoef, Suzanne; Gao, Nisi; Ruijssenaars, Harald J; de Winde, Johannes H

    2014-01-25

    Crude glycerol is a promising renewable feedstock in bioconversion processes for the production of fuels and chemicals. Impurities present in crude glycerol can however, negatively impact the fermentation process. Successful crude glycerol utilization requires robust microbial production hosts that tolerate and preferably, can utilize such impurities. We investigated utilization of crude, unpurified glycerol as a substrate for the production of aromatic compounds by solvent tolerant Pseudomonas putida S12. In high-cell density fed-batch fermentations, P. putida S12 surprisingly performed better on crude glycerol than on purified glycerol. By contrast, growth of Escherichia coli was severely compromised under these high cell density cultivation conditions on crude glycerol. For P. putida S12 the biomass-to-substrate yield, maximum biomass production rate and substrate uptake rate were consistently higher on crude glycerol. Moreover, production of p-hydroxybenzoate by engineered P. putida S12palB5 on crude glycerol showed a 10% yield improvement over production on purified glycerol. P. putida S12 is a favorable host for bioconversion processes utilizing crude glycerol as a substrate. Its intrinsic stress-tolerance properties provide the robustness required for efficient growth and metabolism on this renewable substrate. PMID:23999132

  19. Batch stage study of lipid production from crude glycerol derived from yellow grease or animal fats through microalgal fermentation.

    PubMed

    Liang, Yanna; Sarkany, Nicolas; Cui, Yi; Blackburn, James W

    2010-09-01

    A marine microalga, Schizochytrium limacinum SR21 has been found to grow fast on crude glycerol - a major by-product from the current biodiesel industry. Using crude glycerol derived from restaurant used oils (yellow grease), we have determined that glycerol concentrations of 25 and 35 g/l were the optimal ones for untreated and treated crude glycerol in batch cultures, respectively. Biomass dry weight as 8.3 and 13.3g/l were attained for these two doses, respectively. Higher concentrations of glycerol resulted in decreased cell growth due to substrate inhibition and methanol presence. With 35 g/l, the cellular lipid content was the highest - 73.3% among all the doses tested. Animal fats derived crude glycerol also supported algal growth and lipid production. Results from this study set a solid foundation for our ongoing fed-batch process to achieve maximal crude glycerol utilization and lipid production. PMID:20381345

  20. Nonlinear secret image sharing scheme.

    PubMed

    Shin, Sang-Ho; Lee, Gil-Je; Yoo, Kee-Young

    2014-01-01

    Over the past decade, most of secret image sharing schemes have been proposed by using Shamir's technique. It is based on a linear combination polynomial arithmetic. Although Shamir's technique based secret image sharing schemes are efficient and scalable for various environments, there exists a security threat such as Tompa-Woll attack. Renvall and Ding proposed a new secret sharing technique based on nonlinear combination polynomial arithmetic in order to solve this threat. It is hard to apply to the secret image sharing. In this paper, we propose a (t, n)-threshold nonlinear secret image sharing scheme with steganography concept. In order to achieve a suitable and secure secret image sharing scheme, we adapt a modified LSB embedding technique with XOR Boolean algebra operation, define a new variable m, and change a range of prime p in sharing procedure. In order to evaluate efficiency and security of proposed scheme, we use the embedding capacity and PSNR. As a result of it, average value of PSNR and embedding capacity are 44.78 (dB) and 1.74t⌈log2 m⌉ bit-per-pixel (bpp), respectively. PMID:25140334

  1. Nonlinear Secret Image Sharing Scheme

    PubMed Central

    Shin, Sang-Ho; Yoo, Kee-Young

    2014-01-01

    Over the past decade, most of secret image sharing schemes have been proposed by using Shamir's technique. It is based on a linear combination polynomial arithmetic. Although Shamir's technique based secret image sharing schemes are efficient and scalable for various environments, there exists a security threat such as Tompa-Woll attack. Renvall and Ding proposed a new secret sharing technique based on nonlinear combination polynomial arithmetic in order to solve this threat. It is hard to apply to the secret image sharing. In this paper, we propose a (t, n)-threshold nonlinear secret image sharing scheme with steganography concept. In order to achieve a suitable and secure secret image sharing scheme, we adapt a modified LSB embedding technique with XOR Boolean algebra operation, define a new variable m, and change a range of prime p in sharing procedure. In order to evaluate efficiency and security of proposed scheme, we use the embedding capacity and PSNR. As a result of it, average value of PSNR and embedding capacity are 44.78 (dB) and 1.74t⌈log2⁡m⌉ bit-per-pixel (bpp), respectively. PMID:25140334

  2. Effect of glycerol on retention time and electrical properties of polymer bistable memory devices based on glycerol-modified PEDOT:PSS.

    PubMed

    Park, Boongik; Lee, Junhwan; Kim, Ohyun

    2012-01-01

    The addition of glycerol to Poly(3,4-ethylenedioxythiophene):Poly(styrene sulfonate) (PEDOT:PSS) films affected the bipolar switching characteristics of nonvolatile polymer memory devices (PMDs). Increasing the glycerol/PEDOT:PSS ratio caused increase in the OFF-current of the PMDs, but did not affect the ON-current levels. This result demonstrates that highly-conductive current paths occur in the ON-state. The write-read-erase-read cycle test was operated > 10(5) times. And, the ON-retention time is largely dependent on the glycerol to PEDOT:PSS ratio and annealing temperature. In addition, AFM analysis on the G-PEDOT:PSS films to see how the surface morphology of G-PEDOT:PSS layer influences the retention time properties was carried out. PMID:22524004

  3. Bioremediation of Parboiled Rice Effluent Supplemented with Biodiesel-Derived Glycerol Using Pichia pastoris X-33

    PubMed Central

    Gil de los Santos, Diego; Gil Turnes, Carlos; Rochedo Conceição, Fabricio

    2012-01-01

    This paper describes the use of Pichia pastoris X-33 as a bioremediator to reduce the chemical oxygen demand (COD), total Kjeldahl nitrogen (TKN), and phosphorus (P-PO4   3−), after culture in parboiled rice effluent supplemented with p.a. glycerol or a glycerol by-product of the biodiesel industry. The greatest reduction in the COD (55%), TKN (45%), and P-PO4   3− (52%) of the effluent was observed in cultures of P. pastoris X-33 supplemented with 15 g ·L−1 of biodiesel-derived glycerol. Furthermore, the overall biomass yield was 2.1 g ·L−1. These data suggest that biodiesel-derived glycerol is an efficient carbon source for the bioremediation of parboiled rice effluent and biomass production. PMID:22919327

  4. Enzymatic coproduction of biodiesel and glycerol carbonate from soybean oil and dimethyl carbonate.

    PubMed

    Seong, Pil-Je; Jeon, Byoung Wook; Lee, Myunggu; Cho, Dae Haeng; Kim, Duk-Ki; Jung, Kwang S; Kim, Seung Wook; Han, Sung Ok; Kim, Yong Hwan; Park, Chulhwan

    2011-05-01

    The enzymatic coproduction of biodiesel and glycerol carbonate by the transesterification of soybean oil was studied using lipase as catalyst in organic solvent. To produce biodiesel and glycerol carbonate simultaneously, experiments were designed sequentially. Enzyme screening, the molar ratio of dimethyl carbonate (DMC) to soybean oil, reaction temperature and solvent effects were investigated. The results of enzyme screening, at 100 g/L Novozym 435 (immobilized Candida antarctica lipase B), biodiesel and glycerol carbonate showed conversions of 58.7% and 50.7%, respectively. The optimal conditions were 60 °C, 100 g/L Novozym 435, 6.0:1 molar ratio with tert-butanol as solvent: 84.9% biodiesel and 92.0% glycerol carbonate production was achieved. PMID:22113023

  5. Investigating the potential for cryopreservation of human granulocytes with concentrated glycerol.

    PubMed

    Moss, Alden C; Higgins, Adam Z

    2016-06-01

    The purpose of this study was to investigate the potential for cryopreservation of granulocytes using 30% glycerol. Recently reported permeability data was used to design two different methods for addition and removal of glycerol: a fast method that is predicted to keep cell volumes between 80% and 150% of the isotonic volume and a slow method that is predicted to keep cell volumes between 80% and 115% of the isotonic volume. The fast method resulted in cell recoveries of 31% ± 9% and 11% ± 3% before and after freezing, respectively, whereas the slow method resulted in even lower cell recoveries of 5% ± 2% and 4% ± 2%. The reduced cell recovery for the slow method is consistent with an increase in damage as a result of glycerol toxicity. Our results suggest that cryopreservation of granulocytes in concentrated glycerol is not feasible. PMID:27182034

  6. Converting crude glycerol derived from yellow grease to lipids through yeast fermentation.

    PubMed

    Liang, Yanna; Cui, Yi; Trushenski, Jesse; Blackburn, James W

    2010-10-01

    Cryptococcus curvatus, an oleaginous yeast was observed to grow on crude glycerol derived from yellow grease. When cultured in a one-stage fed-batch process wherein crude glycerol and nitrogen source were fed intermittently for 12 days, the final biomass density and lipid content were 31.2 g/l and 44.2%, respectively. When cultured in a two-stage fed-batch operation wherein crude glycerol was supplemented at different time points while nitrogen source addition was discontinued at the middle of the experiment, the biomass density was 32.9 g/l and the lipid content was 52% at the end of 12 days. Compared with other oil feedstocks for biodiesel production, lipid accumulated by C. curvatus grown on glycerol has high concentration of monounsaturated fatty acid, which makes it an excellent source for biodiesel use. PMID:20478702

  7. INTEGRATION OF SYSTEMS ENGINEERING AND PROCESS INTENSIFICATION IN THE DESIGN OF PROCESSES FOR UTILIZING BIOBASED GLYCEROL

    EPA Science Inventory

    The expected results include an integrated process and mechanical design including a fabrication plan for the glycerol dehydration reactor, comprehensive heat and material balance, environmental impact assessment and comprehensive safety review. The resulting process design w...

  8. Insect glycerol transporters evolved by functional co-option and gene replacement

    PubMed Central

    Finn, Roderick Nigel; Chauvigné, François; Stavang, Jon Anders; Belles, Xavier; Cerdà, Joan

    2015-01-01

    Transmembrane glycerol transport is typically facilitated by aquaglyceroporins in Prokaryota and Eukaryota. In holometabolan insects however, aquaglyceroporins are absent, yet several species possess polyol permeable aquaporins. It thus remains unknown how glycerol transport evolved in the Holometabola. By combining phylogenetic and functional studies, here we show that a more efficient form of glycerol transporter related to the water-selective channel AQP4 specifically evolved and multiplied in the insect lineage, resulting in the replacement of the ancestral branch of aquaglyceroporins in holometabolan insects. To recapitulate this evolutionary process, we generate specific mutants in distantly related insect aquaporins and human AQP4 and show that a single mutation in the selectivity filter converted a water-selective channel into a glycerol transporter at the root of the crown clade of hexapod insects. Integration of phanerozoic climate models suggests that these events were associated with the emergence of complete metamorphosis and the unparalleled radiation of insects. PMID:26183829

  9. Optimization of fermentation condition favoring butanol production from glycerol by Clostridium pasteurianum DSM 525.

    PubMed

    Sarchami, Tahereh; Johnson, Erin; Rehmann, Lars

    2016-05-01

    Butanol is a promising biofuel and valuable platform chemical that can be produced through fermentative conversion of glycerol. The initial fermentation conditions for butanol production from pure glycerol by Clostridium pasteurianum DSM 525 were optimized via a central composite design. The effect of inoculum age, initial cell density, initial pH of medium and temperature were quantified and a quadratic model was able to predict butanol yield as a function of all four investigated factors. The model was confirmed through additional experiments and via analysis of variance (ANOVA). Subsequently, numerical optimization was used to maximize the butanol yield within the experimental range. Based on these results, batch fermentations in a 7 L bioreactor were performed using pure and crude (residue from biodiesel production) glycerol as substrates at optimized conditions. A butanol yield of 0.34 mole(butanol) mole(-1)(glycerol) was obtained indicating the suitability of this feedstock for fermentative butanol production. PMID:26922315

  10. Kinetic analysis of dihydroxyacetone production from crude glycerol by immobilized cells of Gluconobacter oxydans MTCC 904.

    PubMed

    Dikshit, Pritam Kumar; Moholkar, Vijayanand S

    2016-09-01

    The present study has investigated kinetic features of bioconversion of biodiesel-derived crude glycerol to dihydroxyacetone with immobilized Gluconobacter oxydans cells using modified Haldane substrate-inhibition model. The results have been compared against free cells and pure glycerol. Relative variations in the kinetic parameters KS, KI, Vmax, n and X reveal that immobilized G. oxydans cells (on PU foam substrate) with crude glycerol as substrate give higher order of inhibition (n) and lower maximum reaction velocities (Vmax). These results are essentially implications of substrate transport restrictions across immobilization matrix, which causes retention of substrate in the matrix and reduction in fractional available substrate (X) for the cells. This causes reduction in both KS (substrate concentration at Vmax/2) and KI (inhibition constant) as compared to free cells. For immobilized cells, substrate concentration (Smax) corresponding to Vmax is practically same for both pure and crude glycerol as substrate. PMID:27343447

  11. Zeolitic Core@Shell Adsorbents for the Selective Removal of Free Glycerol from Crude Biodiesel.

    PubMed

    Masoumifard, Nima; Arnal, Pablo M; Kaliaguine, Serge; Kleitz, Freddy

    2015-06-22

    Selective adsorption of free glycerol from crude biodiesel was investigated by using mesoporous silica spheres coated with a thin shell of microporous silicalite-1. A polycrystalline silicalite-1 shell was formed upon first covering the external surfaces of various core templates with discrete silicalite-1 nanocrystals, and this was followed by short hydrothermal treatment to ensure shell uniformity. Batch glycerol adsorption experiments were conducted to evaluate the ability of the sorbents to remove free glycerol selectively from crude biodiesel mixtures at various temperatures, also in comparison to that of conventional sorbents, for example, bare mesoporous silica gel spheres and zeolites. The silicalite-1 shell provided a microporous membrane that hindered the diffusion of fatty acid methyl esters into the mesopores of the composite sorbent, whereas the large pore volume of the mesoporous core enabled multilayer glycerol adsorption; this ultimately substantially enhanced the performance in terms of purification yield and adsorption capacity. PMID:26059701

  12. Insect glycerol transporters evolved by functional co-option and gene replacement.

    PubMed

    Finn, Roderick Nigel; Chauvigné, François; Stavang, Jon Anders; Belles, Xavier; Cerdà, Joan

    2015-01-01

    Transmembrane glycerol transport is typically facilitated by aquaglyceroporins in Prokaryota and Eukaryota. In holometabolan insects however, aquaglyceroporins are absent, yet several species possess polyol permeable aquaporins. It thus remains unknown how glycerol transport evolved in the Holometabola. By combining phylogenetic and functional studies, here we show that a more efficient form of glycerol transporter related to the water-selective channel AQP4 specifically evolved and multiplied in the insect lineage, resulting in the replacement of the ancestral branch of aquaglyceroporins in holometabolan insects. To recapitulate this evolutionary process, we generate specific mutants in distantly related insect aquaporins and human AQP4 and show that a single mutation in the selectivity filter converted a water-selective channel into a glycerol transporter at the root of the crown clade of hexapod insects. Integration of phanerozoic climate models suggests that these events were associated with the emergence of complete metamorphosis and the unparalleled radiation of insects. PMID:26183829

  13. Cyanamide mediated synthesis under plausible primitive earth conditions. VI - The synthesis of glycerol and glycerophosphates

    NASA Technical Reports Server (NTRS)

    Epps, D. E.; Nooner, D. W.; Eichberg, J.; Sherwood, E.; Oro, J.

    1979-01-01

    The formation of glycerol occurs when a solution of DL-glyceraldehyde is heated in the presence of hydrogen sulfide at room temperature. DL-glyceraldehyde and dihydroxyacetone treated with hydrazine, as well as DL-glyceraldehyde incubated with formaldehyde are also partially converted to glycerol. The yields of the above reactions are from approximately 1% to about 3%. The formation of glycerophosphates occurs when glycerol is heated with ammonium dihydrogen phosphate and either urea or cyanamide. The yield of glycerophosphates is about 30%, most of which is sn-glycero-1(3)-phosphate. These findings indicate that glycerol and sn-glycero-3-phosphate, which are moieties of glycerolipids, could have been formed under conditions which may have prevailed on the primitive earth.

  14. Strain variation in microalgal lipid production during mixotrophic growth with glycerol.

    PubMed

    Paranjape, Kiran; Leite, Gustavo B; Hallenbeck, Patrick C

    2016-03-01

    Algal cultivation at high latitudes is challenged by the relatively low annual solar flux. One possible scenario to overcome this limitation is the use of mixotrophic growth to potentially boost biomass and lipid production. Here the effect of glycerol addition on the growth and lipid production by twelve indigenous microalgae was examined. The results show that there is considerable strain dependent variation in the maximum growth rate under mixotrophic conditions with the addition of glycerol causing in some cases up to a 2.4-fold increase in growth rate and a up to a 1.9-fold increase in biomass. In addition, glycerol increased total lipid production 40-60% in some strains. These results also show the value in screening culture collections for desired traits independent of strain identification since here one (PCH02) of the five Chlorella strains showed a large increase in lipid with glycerol. PMID:26773947

  15. Glass polymorphism in glycerol-water mixtures: I. A computer simulation study.

    PubMed

    Jahn, David A; Wong, Jessina; Bachler, Johannes; Loerting, Thomas; Giovambattista, Nicolas

    2016-04-28

    We perform out-of-equilibrium molecular dynamics (MD) simulations of water-glycerol mixtures in the glass state. Specifically, we study the transformations between low-density (LDA) and high-density amorphous (HDA) forms of these mixtures induced by compression/decompression at constant temperature. Our MD simulations reproduce qualitatively the density changes observed in experiments. Specifically, the LDA-HDA transformation becomes (i) smoother and (ii) the hysteresis in a compression/decompression cycle decreases as T and/or glycerol content increase. This is surprising given the fast compression/decompression rates (relative to experiments) accessible in MD simulations. We study mixtures with glycerol molar concentration χ(g) = 0-13% and find that, for the present mixture models and rates, the LDA-HDA transformation is detectable up to χ(g) ≈ 5%. As the concentration increases, the density of the starting glass (i.e., LDA at approximately χ(g) ≤ 5%) rapidly increases while, instead, the density of HDA remains practically constant. Accordingly, the LDA state and hence glass polymorphism become inaccessible for glassy mixtures with approximately χ(g) > 5%. We present an analysis of the molecular-level changes underlying the LDA-HDA transformation. As observed in pure glassy water, during the LDA-to-HDA transformation, water molecules within the mixture approach each other, moving from the second to the first hydration shell and filling the first interstitial shell of water molecules. Interestingly, similar changes also occur around glycerol OH groups. It follows that glycerol OH groups contribute to the density increase during the LDA-HDA transformation. An analysis of the hydrogen bond (HB)-network of the mixtures shows that the LDA-HDA transformation is accompanied by minor changes in the number of HBs of water and glycerol. Instead, large changes in glycerol and water coordination numbers occur. We also perform a detailed analysis of the effects that

  16. The physiology of salivary secretion.

    PubMed

    Proctor, Gordon B

    2016-02-01

    Saliva in the mouth is a biofluid produced mainly by three pairs of major salivary glands--the submandibular, parotid and sublingual glands--along with secretions from many minor submucosal salivary glands. Salivary gland secretion is a nerve-mediated reflex and the volume of saliva secreted is dependent on the intensity and type of taste and on chemosensory, masticatory or tactile stimulation. Long periods of low (resting or unstimulated) flow are broken by short periods of high flow, which is stimulated by taste and mastication. The nerve-mediated salivary reflex is modulated by nerve signals from other centers in the central nervous system, which is most obvious as hyposalivation at times of anxiety. An example of other neurohormonal influences on the salivary reflex is the circadian rhythm, which affects salivary flow and ionic composition. Cholinergic parasympathetic and adrenergic sympathetic autonomic nerves evoke salivary secretion, signaling through muscarinic M3 and adrenoceptors on salivary acinar cells and leading to secretion of fluid and salivary proteins. Saliva gland acinar cells are chloride and sodium secreting, and the isotonic fluid produced is rendered hypotonic by salivary gland duct cells as it flows to the mouth. The major proteins present in saliva are secreted by salivary glands, creating viscoelasticity and enabling the coating of oral surfaces with saliva. Salivary films are essential for maintaining oral health and regulating the oral microbiome. Saliva in the mouth contains a range of validated and potential disease biomarkers derived from epithelial cells, neutrophils, the microbiome, gingival crevicular fluid and serum. For example, cortisol levels are used in the assessment of stress, matrix metalloproteinases-8 and -9 appear to be promising markers of caries and periodontal disease, and a panel of mRNA and proteins has been proposed as a marker of oral squamous cell carcinoma. Understanding the mechanisms by which components enter

  17. Cooperative secretions facilitate host range expansion in bacteria

    PubMed Central

    McNally, Luke; Viana, Mafalda; Brown, Sam P.

    2014-01-01

    The majority of emergent human pathogens are zoonotic in origin, that is, they can transmit to humans from other animals. Understanding the factors underlying the evolution of pathogen host range is therefore of critical importance in protecting human health. There are two main evolutionary routes to generalism: organisms can tolerate multiple environments or they can modify their environments to forms to which they are adapted. Here we use a combination of theory and a phylogenetic comparative analysis of 191 pathogenic bacterial species to show that bacteria use cooperative secretions that modify their environment to extend their host range and infect multiple host species. Our results suggest that cooperative secretions are key determinants of host range in bacteria, and that monitoring for the acquisition of secreted proteins by horizontal gene transfer can help predict emerging zoonoses. PMID:25091146

  18. Adaptation of acidogenic sludge to increasing glycerol concentrations for biohydrogen production.

    PubMed

    Tapia-Venegas, E; Cabrol, L; Brandhoff, B; Hamelin, J; Trably, E; Steyer, J P; Ruiz-Filippi, G

    2015-10-01

    Hydrogen is a promising alternative as an energetic carrier and its production by dark fermentation from wastewater has been recently proposed, with special attention to crude glycerol as potential substrate. In this study, two different feeding strategies were evaluated for replacing the glucose substrate by glycerol substrate: a one-step strategy (glucose was replaced abruptly by glycerol) and a step-by-step strategy (progressive decrease of glucose concentration and increase of glycerol concentration from 0 to 5 g L(-1)), in a continuous stirred tank reactor (12 h of hydraulic retention time (HRT), pH 5.5, 35 °C). While the one-step strategy led to biomass washout and unsuccessful H2 production, the step-by-step strategy was efficient for biomass adaptation, reaching acceptable hydrogen yields (0.4 ± 0.1 molH2 mol(-1) glycerol consumed) around 33 % of the theoretical yield independently of the glycerol concentration. Microbial community structure was investigated by single-strand conformation polymorphism (SSCP) and denaturing gradient gel electrophoresis (DGGE) fingerprinting techniques, targeting either the total community (16S ribosomal RNA (rRNA) gene) or the functional Clostridium population involved in H2 production (hydA gene), as well as by 454 pyrosequencing of the total community. Multivariate analysis of fingerprinting and pyrosequencing results revealed the influence of the feeding strategy on the bacterial community structure and suggested the progressive structural adaptation of the community to increasing glycerol concentrations, through the emergence and selection of specific species, highly correlated to environmental parameters. Particularly, this work highlighted an interesting shift of dominant community members (putatively responsible of hydrogen production in the continuous stirred tank reactor (CSTR)) according to the gradient of glycerol proportion in the feed, from the family Veillonellaceae to the genera Prevotella and

  19. Lipid and citric acid production by wild yeasts grown in glycerol.

    PubMed

    Souza, Karla Silva Teixeira; Schwan, Rosane Freitas; Dias, Disney Ribeiro

    2014-04-01

    In this study, crude glycerol was used as a carbon source in the cultivation of wild yeasts, aiming for the production of microbial lipids and citric acid. Forty yeasts of different sources were tested concerning their growth in crude and commercial glycerol. Four yeasts (Lidnera saturnus UFLA CES-Y677, Yarrowia lipolytica UFLA CM-Y9.4, Rhodotorula glutinis NCYC 2439, and Cryptococcus curvatus NCYC 476) were then selected owing to their ability to grow in pure (OD600 2.133, 1.633, 2.055, and 2.049, respectively) and crude (OD600 2.354, 1.753, 2.316, and 2.281, respectively) glycerol (10%, 20%, and 30%). Y. lipolytica UFLA CM-Y9.4 was selected for its ability to maintain cell viability in concentrations of 30% of crude glycerol, and high glycerol intake (18.907 g/l). This yeast was submitted to lipid production in 30 g/l of crude glycerol, and therefore obtained 63.4% of microbial lipids. In the fatty acid profile, there was a predominance of stearic (C18:0) and palmitic (C16:0) acids in the concentrations of 87.64% and 74.67%, respectively. We also performed optimization of the parameters for the production of citric acid, which yielded a production of 0.19 g/l of citric acid in optimum conditions (38.4 g/l of crude glycerol, agitation of 184 rpm, and temperature of 30°C). Yarrowia lipolytica UFLA CM-Y9.4 presented good lipid production when in the concentration of 30 g/l of glycerol. These data may be used for production in large quantities for the application of industrial biodiesel. PMID:24473455

  20. Dependence of NO recombination dynamics in horse myoglobin on solution glycerol content

    SciTech Connect

    Shreve, A.P.; Franzen, S.; Simpson, M.C.; Dyer, R.B.

    1999-09-16

    The recombination dynamics of NO with horse heart myoglobin (Mb) following photolysis with a 570 nm excitation pulse were measured by time-resolved absorption with 250 fs temporal resolution. These measurements were carried out in room-temperature solutions in which the glycerol concentration was varied from 0 to 90% (w/v). The recombination of NO is nonsingle exponential in all cases,m but becomes faster as the glycerol concentration is increased. The interpretation of these results is aided by a maximum entropy analysis to determine a distribution of rate processes consistent with the data. This analysis suggests that in buffer there are two dominant rate processes for NO recombination on the subnanosecond time scale, one at {approx}10 ps and one at {approx}200 ps. The dominant effect of increasing glycerol content is to increase the amplitude of the fast process, with no corresponding significant change in rate, and to decrease the amplitude of the slow process, with no corresponding significant change in rate, and to decrease the amplitude of the slow process, but with a corresponding increase in rate. These results are consistent with a photodissociation process in which photolyzed NO partitions immediately between two distinct populations, one of which has a rapid and the other of which has a slower recombination. The rate of the rapid recombination is independent of glycerol concentration, and therefore decoupled from any protein relaxation process influenced by glycerol, while that of the slower recombination increases at higher glycerol concentration. Further, the partitioning between these two populations also depends on glycerol content, with the relative amplitude of the faster recombination process increasing as the glycerol content is increased. Interpretation of these observations in terms of ligand trajectories following photodissociation, and possible connections of these results with both infrared and crystallographic studies of photodissociated

  1. Mutations and phenotype in isolated glycerol kinase deficiency.

    PubMed Central

    Walker, A. P.; Muscatelli, F.; Stafford, A. N.; Chelly, J.; Dahl, N.; Blomquist, H. K.; Delanghe, J.; Willems, P. J.; Steinmann, B.; Monaco, A. P.

    1996-01-01

    We demonstrate that isolated glycerol kinase (GK) deficiency in three families results from mutation of the Xp21 GK gene. GK mutations were detected in four patients with widely differing phenotypes. Patient 1 had a splice-site mutation causing premature termination. His general health was good despite absent GK activity, indicating that isolated GK deficiency can be silent. Patient 2 had GK deficiency and a severe phenotype involving psychomotor retardation and growth delay, bone dysplasia, and seizures, similar to the severe phenotype of one of the first described cases of GK deficiency. His younger brother, patient 3, also had GK deficiency, but so far his development has been normal. GK exon 17 was deleted in both brothers, implicating additional factors in causation of the severe phenotype of patient 2. Patient 4 had both GK deficiency with mental retardation and a GK missense mutation (D440V). Possible explanations for the phenotypic variation of these four patients include ascertainment bias; metabolic or environmental stress as a precipitating factor in revealing GK-related changes, as has previously been described in juvenile GK deficiency; and interactions with functional polymorphisms in other genes that alter the effect of GK deficiency on normal development. Images Figure 1 Figure 2 Figure 3 Figure 4 PMID:8651297

  2. Molecular Dynamics Simulations of Glycerol Monooleate Confined between Mica Surfaces.

    PubMed

    Bradley-Shaw, Joshua L; Camp, Philip J; Dowding, Peter J; Lewtas, Ken

    2016-08-01

    The structure and frictional properties of glycerol monooleate (GMO) in organic solvents, with and without water impurity, confined and sheared between two mica surfaces are examined using molecular dynamics simulations. The structure of the fluid is characterized in various ways, and the differences between systems with nonaggregated GMO and with preformed GMO reverse micelles are examined. Preformed reverse micelles are metastable under static conditions in all systems. In n-heptane under shear conditions, with or without water, preformed GMO reverse micelles remain intact and adsorb onto one surface or another, becoming surface micelles. In dry toluene, preformed reverse micelles break apart under shear, while in the presence of water, the reverse micelles survive and become surface micelles. In all systems under static and shear conditions, nonaggregated GMO adsorbs onto both surfaces with roughly equal probability. Added water is strongly associated with the GMO, irrespective of shear or the form of the added GMO. In all cases, with increasing shear rate, the GMO molecules flatten on the surface, and the kinetic friction coefficient increases. Under low-shear conditions, the friction is insensitive to the form of the GMO added, whereas the presence of water is found to lead to a small reduction in friction. Under high-shear conditions, the presence of reverse micelles leads to a significant reduction in friction, whereas the presence of water increases the friction in n-heptane and decreases the friction in toluene. PMID:27429247

  3. Glycerol Production by Fermenting Yeast Cells Is Essential for Optimal Bread Dough Fermentation

    PubMed Central

    Aslankoohi, Elham; Rezaei, Mohammad Naser; Vervoort, Yannick; Courtin, Christophe M.; Verstrepen, Kevin J.

    2015-01-01

    Glycerol is the main compatible solute in yeast Saccharomyces cerevisiae. When faced with osmotic stress, for example during semi-solid state bread dough fermentation, yeast cells produce and accumulate glycerol in order to prevent dehydration by balancing the intracellular osmolarity with that of the environment. However, increased glycerol production also results in decreased CO2 production, which may reduce dough leavening. We investigated the effect of yeast glycerol production level on bread dough fermentation capacity of a commercial bakery strain and a laboratory strain. We find that Δgpd1 mutants that show decreased glycerol production show impaired dough fermentation. In contrast, overexpression of GPD1 in the laboratory strain results in increased fermentation rates in high-sugar dough and improved gas retention in the fermenting bread dough. Together, our results reveal the crucial role of glycerol production level by fermenting yeast cells in dough fermentation efficiency as well as gas retention in dough, thereby opening up new routes for the selection of improved commercial bakery yeasts. PMID:25764309

  4. The role of chemisorbed hydroxyl species in alkaline electrocatalysis of glycerol on gold.

    PubMed

    Shi, X; Simpson, D E; Roy, D

    2015-05-01

    The mechanism of energy conversion in a direct glycerol fuel cell (DGFC) is governed by the anode supported heterogeneous steps of glycerol electro-oxidation. In aerated alkaline electrolytes, glycerol also participates in a base catalyzed process, which can release certain species mixing with the anode catalyzed surface products. As a result, selective probing of the surface catalytic reactions involving such systems can be difficult. The present work addresses this issue for a gold anode by using the analytical capability of cyclic voltammetry (CV). In addition, surface plasmon resonance measurements are used to optically probe the adsorption characteristics of the electrolyte species. The net exchange current of the oxidation process and the transfer coefficient of the rate determining step are evaluated by analyzing the CV data. The interfacial reactions and their products on Au are identified by measuring the number of electrons released during the electro-oxidation of glycerol. The results indicate that these reactions are facilitated by the surface bound hydroxyl species on Au (chemisorbed OH(-) and faradaically formed Au-OH). By comparing the findings for stationary and rotating electrodes, it is shown that, convective mass transport is critical to maintaining efficient progression of the consecutive oxidation steps of glycerol. In the absence of hydrodynamic support, the main surface products of glycerol oxidation appear to be glyceraldehyde, glycerate and malonate, formed through a net six-electron route. In the presence of controlled convection, a ten-electron process is activated, where mesaxolate is the likely additional product. PMID:25855265

  5. Glycerol assimilation and production of 1,3-propanediol by Citrobacter amalonaticus Y19.

    PubMed

    Ainala, Satish Kumar; Ashok, Somasundar; Ko, Yeounjoo; Park, Sunghoon

    2013-06-01

    Citrobacter amalonaticus Y19 (Y19) was isolated because of its ability for carbon monoxide-dependent hydrogen production (water-gas shift reaction). This paper reports the assimilation of glycerol and the production of 1,3-propanediol (1,3-PDO) by Y19. Genome sequencing revealed that Y19 contained the genes for the utilization of glycerol and 1,2-propanediol (pdu operon) along with those for the synthesis of coenzyme B12 (cob operon). On the other hand, it did not possess the genes for the fermentative metabolism of glycerol of Klebsiella pneumoniae, which consists of both the oxidative (dhaD and dhaK) and reductive (dhaB and dhaT) pathways. In shake-flask cultivation under aerobic conditions, Y19 could grow well with glycerol as the sole carbon source and produced 1,3-PDO. The level of 1,3-PDO production was improved when vitamin B12 was added to the culture medium under aerobic conditions. Under anaerobic conditions, cell growth and 1,3-PDO production on glycerol was also possible, but only when an exogenous electron acceptor, such as nitrate or fumarate, was added. This is the first report of the glycerol metabolism and 1,3-PDO production by C. amalonaticus Y19. PMID:23377788

  6. Communication: Contrasting effects of glycerol and DMSO on lipid membrane surface hydration dynamics and forces

    NASA Astrophysics Data System (ADS)

    Schrader, Alex M.; Cheng, Chi-Yuan; Israelachvili, Jacob N.; Han, Songi

    2016-07-01

    Glycerol and dimethyl sulfoxide (DMSO) are commonly used cryoprotectants in cellular systems, but due to the challenges of measuring the properties of surface-bound solvent, fundamental questions remain regarding the concentration, interactions, and conformation of these solutes at lipid membrane surfaces. We measured the surface water diffusivity at gel-phase dipalmitoylphosphatidylcholine (DPPC) bilayer surfaces in aqueous solutions containing ≤7.5 mol. % of DMSO or glycerol using Overhauser dynamic nuclear polarization. We found that glycerol similarly affects the diffusivity of water near the bilayer surface and that in the bulk solution (within 20%), while DMSO substantially increases the diffusivity of surface water relative to bulk water. We compare these measurements of water dynamics with those of equilibrium forces between DPPC bilayers in the same solvent mixtures. DMSO greatly decreases the range and magnitude of the repulsive forces between the bilayers, whereas glycerol increases it. We propose that the differences in hydrogen bonding capability of the two solutes leads DMSO to dehydrate the lipid head groups, while glycerol affects surface hydration only as much as it affects the bulk water properties. The results suggest that the mechanism of the two most common cryoprotectants must be fundamentally different: in the case of DMSO by decoupling the solvent from the lipid surface, and in the case of glycerol by altering the hydrogen bond structure and intermolecular cohesion of the global solvent, as manifested by increased solvent viscosity.

  7. Communication: Contrasting effects of glycerol and DMSO on lipid membrane surface hydration dynamics and forces

    PubMed Central

    Schrader, Alex M.; Cheng, Chi-Yuan; Han, Songi

    2016-01-01

    Glycerol and dimethyl sulfoxide (DMSO) are commonly used cryoprotectants in cellular systems, but due to the challenges of measuring the properties of surface-bound solvent, fundamental questions remain regarding the concentration, interactions, and conformation of these solutes at lipid membrane surfaces. We measured the surface water diffusivity at gel-phase dipalmitoylphosphatidylcholine (DPPC) bilayer surfaces in aqueous solutions containing ≤7.5 mol. % of DMSO or glycerol using Overhauser dynamic nuclear polarization. We found that glycerol similarly affects the diffusivity of water near the bilayer surface and that in the bulk solution (within 20%), while DMSO substantially increases the diffusivity of surface water relative to bulk water. We compare these measurements of water dynamics with those of equilibrium forces between DPPC bilayers in the same solvent mixtures. DMSO greatly decreases the range and magnitude of the repulsive forces between the bilayers, whereas glycerol increases it. We propose that the differences in hydrogen bonding capability of the two solutes leads DMSO to dehydrate the lipid head groups, while glycerol affects surface hydration only as much as it affects the bulk water properties. The results suggest that the mechanism of the two most common cryoprotectants must be fundamentally different: in the case of DMSO by decoupling the solvent from the lipid surface, and in the case of glycerol by altering the hydrogen bond structure and intermolecular cohesion of the global solvent, as manifested by increased solvent viscosity. PMID:27475340

  8. Pyrolysis of glycerol for the production of hydrogen or syn gas.

    PubMed

    Valliyappan, T; Bakhshi, N N; Dalai, A K

    2008-07-01

    Biodiesel has high potential as alternative liquid transportation fuel because it is renewable and CO(2) neutral, and has similar properties as diesel fuel. Glycerol is a by-product obtained during the production of biodiesel. Canadian government has planned to produce 500 million litres of biodiesel by 2010. An increase in biodiesel production would decrease the market price of glycerol. The objective of this study is to pyrolyse glycerol for the production of clean fuels such as H(2) or a feedstock such as syn gas for additional transportation fuel via Fisher-Tropsch synthesis. The pyrolysis of glycerol was carried out at various flow rates of N(2) (30-70 mL/min), temperatures (650-800 degrees C) and types and sizes of packing material in a tubular reactor at atmospheric pressure. The products were mostly gas, essentially consisting of CO, H(2), CO(2), CH(4) and C(2)H(4). It was observed that temperature, carrier flow rates and particle diameter of packing material had profound effects on the conversion of glycerol as well as product distribution. Composition of product gas ranged between syn gas 70-93 mol%, CH(4) 3-15 mol% and C(2)H(4) 2-12 mol% and heating value ranged from 13 to 22 MJ/m(3). This study indicates that the bio-glycerol has potential in making syn gas and medium heating value gases. PMID:17951053

  9. Enhanced production of 2,3-butanediol from glycerol by forced pH fluctuations.

    PubMed

    Petrov, Kaloyan; Petrova, Penka

    2010-07-01

    The glycerol fermentation by Klebsiella pneumoniae occurs by receiving more than five liquid products-organic acids, diols, and ethanol. Aiming to direct the glycerol conversion towards predominant production of 2,3-butanediol (2,3-BD), the main influencing parameters (the aeration and the pH) were investigated during fed-batch processes. The regime of intensive aeration (2.2 vvm air supply) was evaluated as most favorable for 2,3-BD synthesis and ensured the decrease of all other metabolites. Thus, without pH control, 52.5 g/l 2,3-BD were produced, as the carbon conversion of glycerol into 2,3-BD reached 60.6%. Additional enhancement in 2,3-BD production (by significant increase of glycerol utilization) was achieved by the development of a new method of "forced pH fluctuations". It was realized by consecutive raisings of pH using definite DeltapH value, at exact time intervals, allowing multiple variations. Thus, the optimal conditions for maximal glycerol consumption were defined, and 70 g/l 2,3-BD were produced, which is the highest amount obtained from glycerol as a sole carbon source until now. The forced pH fluctuations emphasized pH as a governing factor in microbial conversion processes. PMID:20361325

  10. The salt relations of Dunaliella. Further observations on glycerol production and its regulation.

    PubMed

    Borowitzka, L J; Kessly, D S; Brown, A D

    1977-05-13

    Dunaliella tertiolecta (marine) and D. viridis (halophilic) were each trained by serial transfer to grow at salt concentrations previously regarded as the other's domain. D. viridis then had a salt optimum at 1.0-1.5 M sodium chloride whereas that for D. tertiolecta was less than 0-2 M. Nevertheless D. tertiolecta grew faster than the halophil at all salt concentrations up to 3.5 M, the highest at which they were compared. Both species accumulate glycerol, which is necessary for growth at elevated salinities and which responds in its content to water activity (aw) rather than specifically to salt concentration. Variation in glycerol content is a metabolic process which occurs in the dark from accumulated starch as well as photosynthetically. Regulation of glycerol content by aw does not require protein synthesis. The NADP-specific glycerol dehydrogenase of each of the algae is likely to be directly involved in the regulation of glycerol content. Kinetic studies, together with those described in an earlier publication, show that the enzyme has regulatory properties and that both glycerol and dihydroxyacetone act as effectors as well as reactants. A mechanism of the reaction is tentatively proposed. PMID:19000

  11. Biodiesel biorefinery: opportunities and challenges for microbial production of fuels and chemicals from glycerol waste.

    PubMed

    Almeida, João R M; Fávaro, Léia C L; Quirino, Betania F

    2012-01-01

    The considerable increase in biodiesel production worldwide in the last 5 years resulted in a stoichiometric increased coproduction of crude glycerol. As an excess of crude glycerol has been produced, its value on market was reduced and it is becoming a "waste-stream" instead of a valuable "coproduct". The development of biorefineries, i.e. production of chemicals and power integrated with conversion processes of biomass into biofuels, has been singled out as a way to achieve economically viable production chains, valorize residues and coproducts, and reduce industrial waste disposal. In this sense, several alternatives aimed at the use of crude glycerol to produce fuels and chemicals by microbial fermentation have been evaluated. This review summarizes different strategies employed to produce biofuels and chemicals (1,3-propanediol, 2,3-butanediol, ethanol, n-butanol, organic acids, polyols and others) by microbial fermentation of glycerol. Initially, the industrial use of each chemical is briefly presented; then we systematically summarize and discuss the different strategies to produce each chemical, including selection and genetic engineering of producers, and optimization of process conditions to improve yield and productivity. Finally, the impact of the developments obtained until now are placed in perspective and opportunities and challenges for using crude glycerol to the development of biodiesel-based biorefineries are considered. In conclusion, the microbial fermentation of glycerol represents a remarkable alternative to add value to the biodiesel production chain helping the development of biorefineries, which will allow this biofuel to be more competitive. PMID:22809320

  12. Alternative Glycerol Balance Strategies among Saccharomyces Species in Response to Winemaking Stress

    PubMed Central

    Pérez-Torrado, Roberto; Oliveira, Bruno M.; Zemančíková, Jana; Sychrová, Hana; Querol, Amparo

    2016-01-01

    Production and balance of glycerol is essential for the survival of yeast cells in certain stressful conditions as hyperosmotic or cold shock that occur during industrial processes as winemaking. These stress responses are well-known in S. cerevisiae, however, little is known in other phylogenetically close related Saccharomyces species associated with natural or fermentation environments such as S. uvarum, S. paradoxus or S. kudriavzevii. In this work we have investigated the expression of four genes (GPD1, GPD2, STL1, and FPS1) crucial in the glycerol pool balance in the four species with a biotechnological potential (S. cerevisiae; S. paradoxus; S. uvarum; and S. kudriavzevii), and the ability of strains to grow under osmotic and cold stresses. The results show different pattern and level of expression among the different species, especially for STL1. We also studied the function of Stl1 glycerol symporter in the survival to osmotic changes and cell growth capacity in winemaking environments. These experiments also revealed a different functionality of the glycerol transporters among the different species studied. All these data point to different strategies to handle glycerol accumulation in response to winemaking stresses as hyperosmotic or cold-hyperosmotic stress in the different species, with variable emphasis in the production, influx, or efflux of glycerol. PMID:27064588

  13. Enhanced nutrient removal from municipal wastewater assisted by mixotrophic microalgal cultivation using glycerol.

    PubMed

    Gupta, Prabuddha L; Choi, Hee Jeong; Lee, Seung-Mok

    2016-05-01

    In a present study, nutrient removal from municipal wastewater by Chlorella vulgaris and Nannochloropsis oculata was investigated by using mixotrophic cultivation with glycerol (0 to 5 g/L). Performance parameters were assessed by estimating the removal of total nitrogen, total phosphorus, chemical oxygen demand (COD), biomass growth, chlorophyll content, lipid yield, and fatty acids. With the addition of 2 g/L glycerol, a maximum biomass productivity of 56 mg/L/day was achieved in the mixotrophic culture of C. vulgaris within 12 days. The mixotrophic culture showed a 30-fold increase in biomass productivity compared to the wastewater without any glycerol. However, the highest total nitrogen removal (80.62 %), total phosphate removal (60.72 %), and COD removal (96.3 %) was observed in the N. oculata culture supplemented with 3, 5, and 1 g/L glycerol, respectively. These results suggest that mixotrophic cultivation using glycerol offers great potential in the production of renewable biomass, waste water treatment, and consequent production of high-value microalgal oil. Graphical Abstract Simultaneous biomass production and nutrient removal using microalgae cultivated in wastewater supplemented with glycerol. PMID:26867689

  14. Microbial utilization of crude glycerol for the production of value-added products.

    PubMed

    Dobson, Rosemary; Gray, Vincent; Rumbold, Karl

    2012-02-01

    Energy fuels for transportation and electricity generation are mainly derived from finite and declining reserves of fossil hydrocarbons. Fossil hydrocarbons are also used to produce a wide range of organic carbon-based chemical products. The current global dependency on fossil hydrocarbons will not be environmentally or economically sustainable in the long term. Given the future pessimistic prospects regarding the complete dependency on fossil fuels, political and economic incentives to develop carbon neutral and sustainable alternatives to fossil fuels have been increasing throughout the world. For example, interest in biodiesel has undergone a revival in recent times. However, the disposal of crude glycerol contaminated with methanol, salts, and free fatty acids as a by-product of biodiesel production presents an environmental and economic challenge. Although pure glycerol can be utilized in the cosmetics, tobacco, pharmaceutical, and food industries (among others), the industrial purification of crude glycerol is not economically viable. However, crude glycerol could be used as an organic carbon substrate for the production of high-value chemicals such as 1,3-propanediol, organic acids, or polyols. Microorganisms have been employed to produce such high-value chemicals and the objective of this article is to provide an overview of studies on the utilization of crude glycerol by microorganisms for the production of economically valuable products. Glycerol as a by-product of biodiesel production could be used a feedstock for the manufacture of many products that are currently produced by the petroleum-based chemical industry. PMID:21948485

  15. Communication: Contrasting effects of glycerol and DMSO on lipid membrane surface hydration dynamics and forces.

    PubMed

    Schrader, Alex M; Cheng, Chi-Yuan; Israelachvili, Jacob N; Han, Songi

    2016-07-28

    Glycerol and dimethyl sulfoxide (DMSO) are commonly used cryoprotectants in cellular systems, but due to the challenges of measuring the properties of surface-bound solvent, fundamental questions remain regarding the concentration, interactions, and conformation of these solutes at lipid membrane surfaces. We measured the surface water diffusivity at gel-phase dipalmitoylphosphatidylcholine (DPPC) bilayer surfaces in aqueous solutions containing ≤7.5 mol. % of DMSO or glycerol using Overhauser dynamic nuclear polarization. We found that glycerol similarly affects the diffusivity of water near the bilayer surface and that in the bulk solution (within 20%), while DMSO substantially increases the diffusivity of surface water relative to bulk water. We compare these measurements of water dynamics with those of equilibrium forces between DPPC bilayers in the same solvent mixtures. DMSO greatly decreases the range and magnitude of the repulsive forces between the bilayers, whereas glycerol increases it. We propose that the differences in hydrogen bonding capability of the two solutes leads DMSO to dehydrate the lipid head groups, while glycerol affects surface hydration only as much as it affects the bulk water properties. The results suggest that the mechanism of the two most common cryoprotectants must be fundamentally different: in the case of DMSO by decoupling the solvent from the lipid surface, and in the case of glycerol by altering the hydrogen bond structure and intermolecular cohesion of the global solvent, as manifested by increased solvent viscosity. PMID:27475340

  16. High-purity propionate production from glycerol in mixed culture fermentation.

    PubMed

    Chen, Yun; Wang, Ting; Shen, Nan; Zhang, Fang; Zeng, Raymond J

    2016-11-01

    High-purity propionate production from glycerol in mixed culture fermentation (MCF) induced by high ammonium concentration was investigated. Fed-batch experiments revealed that higher ammonium concentration (>2.9g/L) had simultaneous negative effects on acetate and propionate degradation. Propionate production and yield was up to 22.6g/L and 0.45g COD/g COD glycerol, respectively, with a purity of 96%. Sequential batch experiments demonstrated that the yields of propionate were 0.3±0.05, 0.32±0.01, and 0.34±0.03g COD/g COD at a glycerol concentration of 2.78, 4.38, and 5.56g/L, respectively, and the purity of propionate was 91-100%. Microbial community analysis showed that the phylum Firmicutes dominated the bacterial community at different glycerol concentrations. However, the Methanosaeta population decreased from 46% to 6% when glycerol concentration increased from 2.78 to 5.56g/L, resulting in lower acetate degradation rate. Thus, the present study might provide an alternative option for the production of propionate from glycerol via MCF. PMID:27544916

  17. Effects of glycerol on apoptotic signaling pathways during boar spermatozoa cryopreservation.

    PubMed

    Zeng, Changjun; Tang, Keyi; He, Lian; Peng, Wenpei; Ding, Li; Fang, Donghui; Zhang, Yan

    2014-06-01

    Artificial insemination (AI) with post-thawed boar spermatozoa results in low farrowing rates and reduced litter sizes mainly due to cryoinjury or damages to spermatozoa during cryopreservation. Low viability and motility of post-thawed boar spermatozoa are highly associated with apoptosis during cryopreservation. Although glycerol is widely used a cryoprotectant (CPA) for boar spermatozoa cryopreservation, the mechanism and relationship between glycerol and apoptosis-related gene expression needs to be clarified. In this study, we treated boar spermatozoa with different concentrations of glycerol in lactose egg yolk (LEY) extender to evaluate the apoptosis-related gene expression and protease activities of caspases. These results show that: (1) low concentrations of glycerol (2% and 3%) were more suitable for boar spermatozoa cryopreservation; (2) apoptosis-related genes involved in intrinsic mitochondrial and extrinsic death receptor apoptotic signaling pathways were widely expressed in different concentrations of glycerol treated boar spermatozoa; (3) there was a significant positive correlation (r=0.840, P=0.037) between the percentage of Annexin V(+)/PI(+) staining spermatozoa and caspase-6/9 protease activity. In conclusion, 2% and 3% glycerol have the best anti-apoptotic effects, and the expression of Fas/FasL and Bcl-2/Bax have a strong correlation with spermatozoa parameters. PMID:24680861

  18. Consolidating biofuel platforms through the fermentative bioconversion of crude glycerol to butanol.

    PubMed

    Johnson, Erin; Sarchami, Tahereh; Kießlich, Sascha; Munch, Garret; Rehmann, Lars

    2016-06-01

    Economic realities for the rising industrial biofuel production have changed substantially during the low oil price period starting in the mid 2010's. Increased competition requires the sector to increase productivity through the reduction of low-value by-products and full utilization of all value and energy stored in their respective feedstock. Biodiesel is produced commercially from substrates such as animal fat and vegetable oil, generating approximately 10 wt% crude glycerol as its main, currently underutilized, by-product. This crude glycerol is contaminated with catalyst, soap, free fatty acids, glycerides and methyl esters; hence only a small fraction enters the existing glycerol markets, while the purification costs for the majority of crude glycerol are simply too high. However, this presents a unique opportunity to generate additional value. One technical possibility is to use crude glycerol as a carbon source for butanol production, a compound of higher value and energy, a potential additive for gasoline and diesel fuels and bulk chemical commodity. Conversion facilities could be co-located with biodiesel plants, utilizing established infrastructure and adding significant value and productivity to the existing biodiesel industry. This review focuses on the current activities geared towards the bioconversion of crude glycerol to butanol. PMID:27116969

  19. Glycerol production by fermenting yeast cells is essential for optimal bread dough fermentation.

    PubMed

    Aslankoohi, Elham; Rezaei, Mohammad Naser; Vervoort, Yannick; Courtin, Christophe M; Verstrepen, Kevin J

    2015-01-01

    Glycerol is the main compatible solute in yeast Saccharomyces cerevisiae. When faced with osmotic stress, for example during semi-solid state bread dough fermentation, yeast cells produce and accumulate glycerol in order to prevent dehydration by balancing the intracellular osmolarity with that of the environment. However, increased glycerol production also results in decreased CO2 production, which may reduce dough leavening. We investigated the effect of yeast glycerol production level on bread dough fermentation capacity of a commercial bakery strain and a laboratory strain. We find that Δgpd1 mutants that show decreased glycerol production show impaired dough fermentation. In contrast, overexpression of GPD1 in the laboratory strain results in increased fermentation rates in high-sugar dough and improved gas retention in the fermenting bread dough. Together, our results reveal the crucial role of glycerol production level by fermenting yeast cells in dough fermentation efficiency as well as gas retention in dough, thereby opening up new routes for the selection of improved commercial bakery yeasts. PMID:25764309

  20. Production of biohydrogen from crude glycerol in an upflow column bioreactor.

    PubMed

    Dounavis, Athanasios S; Ntaikou, Ioanna; Lyberatos, Gerasimos

    2015-12-01

    A continuous attached growth process for the production of biohydrogen from crude glycerol was developed. The process consisted of an anaerobic up-flow column bioreactor (UFCB), packed with cylindrical ceramic beads, which constituted the support matrix for the attachment of bacterial cells. The effect of crude glycerol concentration, pH and hydraulic retention time on glycerol conversion, hydrogen yield and metabolite distribution was investigated. It was shown that the most critical parameter for the efficient bioconversion was the pH of the influent, whereas the hydrogen yield increased with an increase in feed glycerol concentration and a decrease in the hydraulic retention time. The main soluble metabolite detected was 1,3-propanediol in all cases, followed by butyric and hexanoic acids. The latter is reported to be produced from glycerol for the first time. Acidification of the waste reached 38.5%, and the maximum H2 productivity was 107.3 ± 0.7 L/kg waste glycerol at optimal conditions. PMID:26441027

  1. Wide distribution of autochthonous branched glycerol dialkyl glycerol tetraethers (bGDGTs) in U.S. Great Basin hot springs

    PubMed Central

    Hedlund, Brian P.; Paraiso, Julienne J.; Williams, Amanda J.; Huang, Qiuyuan; Wei, Yuli; Dijkstra, Paul; Hungate, Bruce A.; Dong, Hailiang; Zhang, Chuanlun L.

    2013-01-01

    Branched glycerol dialkyl glycerol tetraethers (bGDGTs) are membrane-spanning lipids that likely stabilize membranes of some bacteria. Although bGDGTs have been reported previously in certain geothermal environments, it has been suggested that they may derive from surrounding soils since bGDGTs are known to be produced by soil bacteria. To test the hypothesis that bGDGTs can be produced by thermophiles in geothermal environments, we examined the distribution and abundance of bGDGTs, along with extensive geochemical data, in 40 sediment and mat samples collected from geothermal systems in the U.S. Great Basin (temperature: 31–95°C; pH: 6.8–10.7). bGDGTs were found in 38 out of 40 samples at concentrations up to 824 ng/g sample dry mass and comprised up to 99.5% of total GDGTs (branched plus isoprenoidal). The wide distribution of bGDGTs in hot springs, strong correlation between core and polar lipid abundances, distinctness of bGDGT profiles compared to nearby soils, and higher concentration of bGDGTs in hot springs compared to nearby soils provided evidence of in situ production, particularly for the minimally methylated bGDGTs I, Ib, and Ic. Polar bGDGTs were found almost exclusively in samples ≤70°C and the absolute abundance of polar bGDGTs correlated negatively with properties of chemically reduced, high temperature spring sources (temperature, H2S/HS−) and positively with properties of oxygenated, low temperature sites (O2, NO−3). Two-way cluster analysis and nonmetric multidimensional scaling based on relative abundance of polar bGDGTs supported these relationships and showed a negative relationship between the degree of methylation and temperature, suggesting a higher abundance for minimally methylated bGDGTs at high temperature. This study presents evidence of the widespread production of bGDGTs in mats and sediments of natural geothermal springs in the U.S. Great Basin, especially in oxygenated, low-temperature sites (≤70°C). PMID:23964271

  2. Development of a regional glycerol dialkyl glycerol tetraether (GDGT)-temperature calibration for Antarctic and sub-Antarctic lakes

    NASA Astrophysics Data System (ADS)

    Foster, Louise C.; Pearson, Emma J.; Juggins, Steve; Hodgson, Dominic A.; Saunders, Krystyna M.; Verleyen, Elie; Roberts, Stephen J.

    2016-01-01

    A regional network of quantitative reconstructions of past climate variability is required to test climate models. In recent studies, temperature calibration models based on the relative abundances of sedimentary glycerol dialkyl glycerol tetraethers (GDGTs) have enabled past temperature reconstructions in both marine and terrestrial environments. Nevertheless, to date these methods have not been widely applied in high latitude environments due to poor performance of the GDGT-temperature calibrations at lower temperatures. To address this we studied 32 lakes from Antarctica, the sub-Antarctic Islands and Southern Chile to: 1) quantify their GDGT composition and investigate the environmental controls on GDGT composition; and 2) develop a GDGT-temperature calibration model for inferring past temperatures from Antarctic and sub-Antarctic lakes. GDGTs were found in all 32 lakes studied and in 31 lakes branched GDGTs (brGDGTs) were the dominant compounds. Statistical analyses of brGDGT composition in relation to temperature, pH, conductivity and water depth showed that the composition of brGDGTs is strongly correlated with mean summer air temperature (MSAT). This enabled the development of the first regional brGDGT-temperature calibration for use in Antarctic and sub-Antarctic lakes using four brGDGT compounds (GDGT-Ib, GDGT-II, GDGT-III and GDGT-IIIb). A key discovery was that GDGT-IIIb is of particular importance in cold lacustrine environments. The addition of this compound significantly improved the model's performance from r2 = 0.67, RMSEP-LOO (leave-one-out) = 2.23 °C, RMSEP-H (h-block) = 2.37 °C when applying the re-calibrated global GDGT-temperature calibration to our Antarctic dataset to r2 = 0.83, RMSEP-LOO = 1.68 °C, RMSEP-H = 1.65 °C for our new Antarctic calibration. This shows that Antarctic and sub-Antarctic, and possibly other high latitude, palaeotemperature reconstructions should be based on a regional GDGT-temperature calibration where specific

  3. In situ produced branched glycerol dialkyl glycerol tetraethers in suspended particulate matter from the Yenisei River, Eastern Siberia

    NASA Astrophysics Data System (ADS)

    De Jonge, Cindy; Stadnitskaia, Alina; Hopmans, Ellen C.; Cherkashov, Georgy; Fedotov, Andrey; Sinninghe Damsté, Jaap S.

    2014-01-01

    Soil-derived branched glycerol dialkyl glycerol tetraethers (brGDGTs) in marine river fan sediments have a potential use for determining changes in the mean annual temperature (MAT) and pH of the river watershed soils. Prior to their incorporation in marine sediments, the compounds are transported to the marine system by rivers. However, emerging evidence suggests that the brGDGTs in freshwater systems can be derived from both soil run-off and in situ production. The production of brGDGTs in the river system can complicate the interpretation of the brGDGT signal delivered to the marine system. Therefore, we studied the distribution of brGDGT lipids in suspended particulate matter (SPM) of the Yenisei River. Chromatographic improvements allowed quantification of the recently described hexamethylated brGDGT isomer, characterized by having two methyl groups at the 6/6‧ instead of the 5/5‧ positions, in an environmental dataset for the first time. This novel compound was the most abundant brGDGT in SPM from the Yenisei. Its fractional abundance correlated well with that of the 6-methyl isomer of the hexamethylated brGDGT that contains one cyclopentane moiety. The Yenisei River watershed is characterized by large differences in MAT (>11 °C) as it spans a large latitudinal range (46-73°N), which would be expected to be reflected in brGDGT distributions of its soils. However, the brGDGT distributions in its SPM show little variation. Furthermore, the reconstructed pH values are high compared to the watershed soil pH. We, therefore, hypothesize that the brGDGTs in the Yenisei River SPM are predominantly produced in situ and not primarily derived from erosion of soil. This accounts for the absence of a change in the temperature signal, as the river water temperature is more stable. Using a lake calibration, the reconstructed temperature values agree with the mean summer temperatures (MST) recorded. The brGDGTs delivered to the sea by the Yenisei River during this

  4. Roles of sugar alcohols in osmotic stress adaptation. Replacement of glycerol by mannitol and sorbitol in yeast

    SciTech Connect

    Shen, B.; Hohmann, S.; Jensen, R.G.; Bohnert, H.J.

    1999-09-01

    For many organisms there is a correlation between increases of metabolites and osmotic stress tolerance, but the mechanisms that cause this protection are not clear. To understand the role of polyols, genes for bacterial mannitol-1-P dehydrogenase and apply sorbitol-6-P dehydrogenase were introduced into a Saccharomyces cerevisiae mutant deficient in glycerol synthesis. Sorbitol and mannitol provided some protection, but less than that generated by a similar concentration of glycerol generated by glycerol-3-P dehydrogenase (GPD1). Reduced protection by polyols suggested that glycerol had specific functions for which mannitol and sorbitol could not substitute, and that the absolute amount of the accumulating osmoticum might not be crucial. The retention of glycerol and mannitol-sorbitol, respectively, was a major difference. During salt stress, cells retained more of the six-carbon polyois than glycerol. The authors suggest that the loss of {gt} 98% of the glycerol synthesized could provide a safety value that dissipates reducing power, which a similar high intracellular concentration of retained polyois would be less protective. To understand the role of glycerol in salt tolerance, salt-tolerant suppressor mutants were isolated from the glycerol-deficient strain. One mutant, sr13, partially suppressed the salt-sensitive phenotype of the glycerol-deficient line, probably due to a doubling of [K{sup +}] accumulating during stress. The authors compare these results to the osmotic adjustment concept typically applied to accumulating metabolites in plants. The accumulation of polyois may have dual functions: facilitating osmotic adjustment and supporting redox control.

  5. Glucose regulation of glucagon secretion.

    PubMed

    Gylfe, Erik; Gilon, Patrick

    2014-01-01

    Glucagon secreted by pancreatic α-cells is the major hyperglycemic hormone correcting acute hypoglycaemia (glucose counterregulation). In diabetes the glucagon response to hypoglycaemia becomes compromised and chronic hyperglucagonemia appears. There is increasing awareness that glucagon excess may underlie important manifestations of diabetes. However opinions differ widely how glucose controls glucagon secretion. The autonomous nervous system plays an important role in the glucagon response to hypoglycaemia. But it is clear that glucose controls glucagon secretion also by mechanisms involving direct effects on α-cells or indirect effects via paracrine factors released from non-α-cells within the pancreatic islets. The present review discusses these mechanisms and argues that different regulatory processes are involved in a glucose concentration-dependent manner. Direct glucose effects on the α-cell and autocrine mechanisms are probably most significant for the glucagon response to hypoglycaemia. During hyperglycaemia, when secretion from β- and δ-cells is stimulated, paracrine inhibitory factors generate pulsatile glucagon release in opposite phase to pulsatile release of insulin and somatostatin. High concentrations of glucose have also stimulatory effects on glucagon secretion that tend to balance and even exceed the inhibitory influence. The latter actions might underlie the paradoxical hyperglucagonemia that aggravates hyperglycaemia in persons with diabetes. PMID:24367972

  6. The role of micronutrients and strategies for optimized continual glycerol production from carbon dioxide by Dunaliella tertiolecta.

    PubMed

    Chow, Yvonne; Tu, Wang Yung; Wang, David; Ng, Daphne H P; Lee, Yuan Kun

    2015-10-01

    The microalga Dunaliella tertiolecta synthesizes intracellular glycerol as an osmoticum to counteract external osmotic pressure in high saline environments. The species has recently been found to release and accumulate extracellular glycerol, making it a suitable candidate for sustainable industrial glycerol production if a sufficiently high product titre yield can be achieved. While macronutrients such as nitrogen and phosphorus are essential and well understood, this study seeks to understand the influence of the micronutrient profile on glycerol production. The effects of metallic elements calcium, magnesium, manganese, zinc, cobalt, copper, and iron, as well as boron, on glycerol production as well as cell growth were quantified. The relationship between cell density and glycerol productivity was also determined. Statistically, manganese recorded the highest improvement in glycerol production as well as cell growth. Further experiments showed that manganese availability was associated with higher superoxide dismutase formation, thus suggesting that glycerol production is negatively affected by oxidative stress and the manganese bound form of this enzyme is required in order to counteract reactive oxygen species in the cells. A minimum concentration of 8.25 × 10(-5)  g L(-1) manganese was sufficient to overcome this problem and achieve 10 g L(-1) extracellular glycerol, compared to 4 g L(-1) without the addition of manganese. Unlike cell growth, extracellular glycerol production was found to be negatively affected by the amount of calcium present in the normal growth medium, most likely due to the lower cell permeability at high calcium concentrations. The inhibitory effects of iron also affected extracellular glycerol production more significantly than cell growth and several antagonistic interaction effects between various micronutrients were observed. This study indicates how the optimization of these small amounts of nutrients in a two

  7. Pancreatic Polypeptide Inhibits Somatostatin Secretion

    PubMed Central

    Kim, Wook; Fiori, Jennifer L.; Shin, Yu-Kyong; Okun, Eitan; Kim, Jung Seok; Rapp, Peter R.; Egan, Josephine M.

    2014-01-01

    Pancreatic polypeptide (PP) is a major agonist for neuropeptide Y4 receptors (NPY4R). While NPY4R has been identified in various tissues, the cells on which it is expressed and its function in those cells has not been clearly delineated. Here we report that NPY4R is present in all somatostatin-containing cells of tissues that we tested, including pancreatic islets, duodenum, hippocampus, and hypothalamus. Its agonism by PP decreases somatostatin secretion from human islets. Mouse embryonic hippocampal (mHippo E18) cells expressed NPY4Rs and their activation by PP consistently decreased somatostatin secretion. Furthermore, central injection of PP in mice induced c-Fos immunoreactivity in somatostatin-containing cells in the hippocampus compared with PBS-injected mice. In sum, our results identify PP as a pivotal modulator of somatostatin secretion. PMID:25019573

  8. Multiparty Quantum Remote Secret Conference

    NASA Astrophysics Data System (ADS)

    Li, Xi-Han; Li, Chun-Yan; Deng, Fu-Guo; Zhou, Ping; Liang, Yu-Jie; Zhou, Hong-Yu

    2007-01-01

    We present two schemes for multiparty quantum remote secret conference in which each legitimate conferee can read out securely the secret message announced by another, but a vicious eavesdropper can get nothing about it. The first one is based on the same key shared efficiently and securely by all the parties with Greenberger-Horne-Zeilinger (GHZ) states, and each conferee sends his secret message to the others with one-time pad crypto-system. The other one is based on quantum encryption with a quantum key, a sequence of GHZ states shared among all the conferees and used repeatedly after confirming their security. Both these schemes are optimal as their intrinsic efficiency for qubits approaches the maximal value.

  9. On family secrets and -K.

    PubMed

    Orgad, Yariv

    2014-08-01

    In this paper I present a novel interpretation of family secrets. Leaning on Bion's concept of -K, the constitution of secrecy is interpreted in terms of family dynamics that actively prevent knowledge formation and mental growth. Family secrets are interpreted as a destructive process that attacks the family's truth-generating-space - the shared semiotic space within which meanings are constituted through family relationships. The paper explores the microstructure interpersonal process of -K through the analysis of Mike Leigh's movie, Secrets and Lies. Two scenes in the movie are used to demonstrate how -K is worked out in the form of a specific intersubjective semiotic endeavor that unconsciously blocks the process of meaning-making. PMID:24902493

  10. Quantitative analysis of urinary glycerol levels for doping control purposes using gas chromatography-mass spectrometry.

    PubMed

    Thevis, Mario; Guddat, Sven; Flenker, Ulrich; Schänzer, Wilhelm

    2008-01-01

    The administration of glycerol to endurance athletes results in an increased fluid retention and improved performance, particularly under hot and humid conditions. Consequently, glycerol is considered relevant for sports drug testing and methods for its detection in urine specimens are required. A major issue in this regard is the natural occurrence of trace amounts of glycerol in human urine, which necessitates a quantitative analysis and the determination of normal urinary glycerol levels under various sporting conditions. A quantitative method was established using a gas chromatography/isotope-dilution mass spectrometry-based approach that was validated with regard to lower limit of detection (0.3 microg mL(-1)), lower limit of quantification (0.9 microg mL(-1)), specificity, linearity (1.0-98.0 microg mL(-1)), intraday and interday precision (<20% at 2.4, 24.1 and 48.2 microg mL(-1)) as well as accuracy (92-110%). Sample aliquots of 20 microL were enriched with five-fold deuterated glycerol, dried and derivatised using N-methyl-trimethylsilyltrifluoroacetamide (MSTFA) before analysis. The established method was applied to a total of 1039 doping control samples covering various sport disciplines (349 endurance samples, 286 strength sport samples, 325 game sport samples and 79 other samples) in- and out-of-competition, which provided quantitative information about the glycerol content commonly observed in elite athletes' urine samples. About 85% of all specimens yielded glycerol concentrations < 20.0 microg mL(-1) and few reached values up to 132.6 microg mL(-1). One further sample, however, was found to contain 2690 microg mL(-1), which might indicate the misuse of glycerol, but no threshold for urinary glycerol concentrations has been established yet due to the lack of substantial data. Based on the results obtained from the studied reference population, a threshold for glycerol levels in urine set at 200 microg mL(-1) is suggested, which provides a tool to

  11. Secrets and Disclosures: How Young Children Handle Secrets

    ERIC Educational Resources Information Center

    Anagnostaki, Lida; Wright, Michael J.; Papathanasiou, Athanasia

    2013-01-01

    The authors examined the influence of content and verbal cues on young children's understanding of secret information and of its disclosure. Participants were 209 5- and 6-year-old children in an experiment where a puppet, named Zinc, was the protagonist. Children were asked to whom Zinc would disclose a list of pieces of information, some of…

  12. Characterization of oleaginous yeasts accumulating high levels of lipid when cultivated in glycerol and their potential for lipid production from biodiesel-derived crude glycerol.

    PubMed

    Polburee, Pirapan; Yongmanitchai, Wichien; Lertwattanasakul, Noppon; Ohashi, Takao; Fujiyama, Kazuhito; Limtong, Savitree

    2015-12-01

    This study attempted to identify oleaginous yeasts and selected the strain that accumulated the largest quantity of lipid for lipid production from glycerol. Two-step screening of 387 yeast strains revealed 23 oleaginous strains that accumulated quantities of lipid higher than 20 % of their biomass when cultivated in glycerol. These strains were identified to be four ascomycetous yeast species i.e. Candida silvae, Kodamaea ohmeri, Meyerozyma caribbica, and Pichia manshurica, and five basidiomycetous yeast species i.e. Cryptococcus cf. podzolicus, Cryptococcus laurentii, Rhodosporidium fluviale, Rhodotorula taiwanensis, and Sporidiobolus ruineniae. Rhodosporidium fluviale DMKU-RK253 accumulated the highest quantity of lipid equal to 65.2 % of its biomass (3.9 g L(-1) lipid and 6.0 g L(-1) biomass) by shaking flask cultivation in crude glycerol. The main fatty acids in the accumulated lipid of this strain consisted of oleic acid, linoleic acid, and palmitic acid. Therefore, R. fluviale DMKU-RK253 has potential for producing lipid for biodiesel manufacturing using crude glycerol as a feedstock. PMID:26615742

  13. Membrane topology of murine glycerol-3-phosphate acyltransferase 2.

    PubMed

    Nakagawa, Tadahiko; Harada, Nagakatsu; Miyamoto, Aiko; Kawanishi, Yukiko; Yoshida, Masaki; Shono, Masayuki; Mawatari, Kazuaki; Takahashi, Akira; Sakaue, Hiroshi; Nakaya, Yutaka

    2012-02-17

    Glycerol-3-phosphate acyltransferase (GPAT) is a rate-limiting enzyme in mammalian triacylglycerol biosynthesis. GPAT is a target for the treatment of metabolic disorders associated with high lipid accumulation. Although the molecular basis for GPAT1 activation has been investigated extensively, the activation of other isoforms, such as GPAT2, is less well understood. Here the membrane topology of the GPAT2 protein was examined using an epitope-tag-based method. Exogenously expressed GPAT2 protein was present in the membrane fraction of transformed HEK293 cells even in the presence of Na(2)CO(3) (100 mM), indicating that GPAT2 is a membrane-bound protein. Trypsin treatment of the membrane fraction degraded the N-terminal (FLAG) and C-terminal (myc-epitope) protein tags of the GPAT2 protein. Bioinformatic analysis of the GPAT2 protein sequence indicated four hydrophobic sequences as potential membrane-spanning regions (TM1-TM4). Immunoblotting of the myc-epitope tag, which was inserted between each TM region of the GPAT2 protein, showed that the amino acid sequence between TM3 and TM4 was protected from trypsin digestion. These results suggest that the GPAT2 protein has two transmembrane segments and that the N-terminal and C-terminal regions of this protein face the cytoplasm. These results also suggest that the enzymatically active motifs I-III of the GPAT2 protein face the cytosol, while motif IV is within the membrane. It is expected that the use of this topological model of GPAT2 will be essential in efforts to elucidate the molecular mechanisms of GPAT2 activity in mammalian cells. PMID:22285183

  14. [Effects of ggpS over-expression on glycosylglycerol and glycerol biosynthesis of Synechocystis sp. PCC 6803].

    PubMed

    Ma, Peizhen; Tan, Xiaoming; Lü, Xuefeng; Tian, Jiyuan

    2016-03-01

    To study the roles of glucosylglycerol phosphate synthase (Ggps) in glucosylglycerol (GG) and glycerol biosynthesis, we over-expressed Ggps from either Synechocystis sp. PCC 6803 or Synechococcus sp. PCC 7002 in a Synechocystis strain with a high GG titer, and determined the GG and glycerol accumulation in the resultant mutants grown under different NaCl-stress conditions. Ion chromatography results revealed that GG yield was not improved, but glycerol production was significantly enhanced by over-expression of Ggps from Synechocystis sp. PCC 6803 (6803ggpS). In addition, increasing the NaCl concentration of medium from 600 to 900 mmol/L led to a further 75% increase of glycerol accumulation in the mutant strain with 6803ggpS over-expression. These findings show the role of ggpS in driving the carbon flux to the glycerol biosynthesis pathway, and will be helpful for further improvement of GG and glycerol production in Synechocystis. PMID:27349117

  15. Structure of glycerol-3-phosphate dehydrogenase (GPD1) from Saccharomyces cerevisiae at 2.45 Å resolution

    PubMed Central

    Alarcon, David Aparicio; Nandi, Munmun; Carpena, Xavi; Fita, Ignacio; Loewen, Peter C.

    2012-01-01

    The interconversion of glycerol 3-phosphate and dihydroxyacetone phosphate by glycerol-3-phosphate dehydrogenases provides a link between carbohydrate and lipid metabolism and provides Saccharomyces cerevisiae with protection against osmotic and anoxic stress. The first structure of a glycerol-3-phosphate dehydrogenase from S. cerevisiae, GPD1, is reported at 2.45 Å resolution. The asymmetric unit contains two monomers, each of which is organized with N- and C-terminal domains. The N-terminal domain contains a classic Rossmann fold with the (β-α-β-α-β)2 motif typical of many NAD+-dependent enzymes, while the C-terminal domain is mainly α-helical. Structural and phylogenetic comparisons reveal four main structure types among the five families of glycerol-3-phosphate and glycerol-1-phosphate dehydrogenases and reveal that the Clostridium acetobutylican protein with PDB code 3ce9 is a glycerol-1-­phosphate dehydrogenase. PMID:23143232

  16. Structural Characterizations of Glycerol Kinase: Unraveling Phosphorylation-Induced Long-Range Activation

    SciTech Connect

    Yeh, Joanne I.; Kettering, Regina; Saxl, Ruth; Bourand, Alexa; Darbon, Emmanuelle; Joly, Nathalie; Briozzo, Pierre; Deutscher, Josef

    2009-09-11

    Glycerol metabolism provides a central link between sugar and fatty acid catabolism. In most bacteria, glycerol kinase plays a crucial role in regulating channel/facilitator-dependent uptake of glycerol into the cell. In the firmicute Enterococcus casseliflavus, this enzyme's activity is enhanced by phosphorylation of the histidine residue (His232) located in its activation loop, approximately 25 A from its catalytic cleft. We reported earlier that some mutations of His232 altered enzyme activities; we present here the crystal structures of these mutant GlpK enzymes. The structure of a mutant enzyme with enhanced enzymatic activity, His232Arg, reveals that residues at the catalytic cleft are more optimally aligned to bind ATP and mediate phosphoryl transfer. Specifically, the position of Arg18 in His232Arg shifts by approximately 1 A when compared to its position in wild-type (WT), His232Ala, and His232Glu enzymes. This new conformation of Arg18 is more optimally positioned at the presumed gamma-phosphate location of ATP, close to the glycerol substrate. In addition to structural changes exhibited at the active site, the conformational stability of the activation loop is decreased, as reflected by an approximately 35% increase in B factors ('thermal factors') in a mutant enzyme displaying diminished activity, His232Glu. Correlating conformational changes to alteration of enzymatic activities in the mutant enzymes identifies distinct localized regions that can have profound effects on intramolecular signal transduction. Alterations in pairwise interactions across the dimer interface can communicate phosphorylation states over 25 A from the activation loop to the catalytic cleft, positioning Arg18 to form favorable interactions at the beta,gamma-bridging position with ATP. This would offset loss of the hydrogen bonds at the gamma-phosphate of ATP during phosphoryl transfer to glycerol, suggesting that appropriate alignment of the second substrate of glycerol kinase

  17. Comparing cellular performance of Yarrowia lipolytica during growth on glucose and glycerol in submerged cultivations

    PubMed Central

    2013-01-01

    Yarrowia lipolytica is an attractive host for sustainable bioprocesses due to its ability to utilize a variety of carbon substrates and convert them to a range of different product types (including lipids, organic acids and polyols) under specific conditions. Despite an increasing number of applications for this yeast, relatively few studies have focused on uptake and metabolism of carbon sources, and the metabolic basis for carbon flow to the different products. The focus of this work was quantification of the cellular performance of Y. lipolytica during growth on glycerol, glucose or a mixture of the two. Carbon substrate uptake rate, growth rate, oxygen utilisation (requirement and uptake rate) and polyol yields were estimated in batch cultivations at 1 litre scale. When glucose was used as the sole carbon and energy source, the growth rate was 0.24 h-1 and biomass and CO2 were the only products. Growth on glycerol proceeded at approximately 0.30 h-1, and the substrate uptake rate was 0.02 mol L-1 h-1 regardless of the starting glycerol concentration (10, 20 or 45 g L-1). Utilisation of glycerol was accompanied by higher oxygen uptake rates compared to glucose growth, indicating import of glycerol occurred initially via phosphorylation of glycerol into glycerol-3-phosphate. Based on these results it could be speculated that once oxygen limitation was reached, additional production of NADH created imbalance in the cofactor pools and the polyol formation observed could be a result of cofactor recycling to restore the balance in metabolism. PMID:24088397

  18. Effects of acetaldehyde on hepatocyte glycerol uptake and cell size: implication of Aquaporin 9

    PubMed Central

    Potter, James J.; Koteish, Ayman; Hamilton, James; Liu, Xiaopu; Liu, Kun; Agre, Peter; Mezey, Esteban

    2010-01-01

    Background The effects of ethanol and acetaldehyde on uptake of glycerol and on cell size of hepatocytes and a role Aquaporin 9 (AQP9), a glycerol transport channel, were evaluated. Methods The studies were done in primary rat and mouse hepatocytes. The uptake of [14C] glycerol was determined with hepatocytes in suspension. For determination of cell size, rat hepatocytes on coated dishes were incubated with a lipophilic fluorochrome that is incorporated into the cell membrane and examined by confocal microscopy. A three dimensional z scan of the cell was performed, and the middle slice of the z scan was used for area measurements. Results Acute exposure to acetaldehyde, but not to ethanol, causes a rapid increase in the uptake of glycerol and an increase in hepatocyte size, which was inhibited by HgCl2, an inhibitor of aquaporins. This was not observed in hepatocytes from AQP9 knockout mice, nor observed by direct application of acetaldehyde to AQP9 expressed in Xenopus Laevis oocytes. Prolonged 24 hours exposure to either acetaldehyde or ethanol did not result in an increase in glycerol uptake by rat hepatocytes. Acetaldehyde decreased AQP9 mRNA and AQP9 protein, while ethanol decreased AQP9 mRNA but not AQP9 protein. Ethanol, but not acetaldehyde, increased the activities of glycerol kinase and phosphoenolpyruvate carboxykinase. Conclusions The acute effects of acetaldehyde, while mediated by AQP9, are probably influenced by binding of acetaldehyde to hepatocyte membranes and changes in cell permeability. The effects of ethanol in enhancing glucose kinase, and phosphoenolpyruvate carboxykinase leading to increased formation of glycerol-3-phosphate most likely contribute to alcoholic fatty liver. PMID:21294757

  19. Effects of glycerol on human skin damaged by acute sodium lauryl sulphate treatment.

    PubMed

    Atrux-Tallau, Nicolas; Romagny, Céline; Padois, Karine; Denis, Alain; Haftek, Marek; Falson, Françoise; Pirot, Fabrice; Maibach, Howard I

    2010-08-01

    Glycerol, widely used as humectant, is known to protect against irritants and to accelerate recovery of irritated skin. However, most studies were done with topical formulations (i.e. emulsions) containing glycerol in relatively high amounts, preventing drawing conclusions from direct effects. In this study, acute chemical irritations were performed on the forearm with application of a 10% sodium lauryl sulphate (SLS) aqueous solution under occlusion for 3 h. Then, glycerol aqueous solutions from 1 to 10% were applied under occlusion for 3 h. After elimination of moist excess consecutive to occlusive condition, in ambient air for 15 and 30 min, skin barrier function was investigated by dual measurement of skin hydration and transepidermal water loss (TEWL). Treatments with SLS solution under occlusion significantly increased TEWL and decreased skin hydration as assessed by capacitance measurements. The SLS irritant property was raised by the occlusion and the water barrier function as well as water content appeared impaired. Recovery with glycerol at low doses was remarkable through a mechanism that implies its hygroscopic properties and which is saturable. This precocious effect acts through skin rehydration by enhancing water-holding capacity of stratum corneum that would facilitate the late physiological repair of impaired skin barrier. Thus, glycerol appears to substitute for natural moisturizing factors that have been washed out by the detergent action of SLS, enhancing skin hydration but without restoring skin barrier function as depicted by TEWL values that remained high. Thus, irritant contact dermatitis treated with glycerol application compensate for skin dehydration, favouring physiological process to restore water barrier function of the impaired skin. Empirical use of glycerol added topical formulations onto detergent altered skin was substantiated in the present physicochemical approach. PMID:20043170

  20. Systematic analysis of glycerol: colourimetric screening and gas chromatography-mass spectrometric confirmation.

    PubMed

    Sardela, Vinícius F; Scalco, Fernanda B; Cavalcante, Karina M; Simoni, Ruth E; Silva, Deyvison R; Pereira, Henrique Marcelo G; de Oliveira, Maria Lúcia L Costa; Aquino Neto, Francisco R

    2015-10-01

    Glycerol is a naturally occurring polyol in the human body, essential for several metabolic processes. It is widely used in the food, pharmaceutical, and medical industries and in clinical practice as a plasma volume expander (PVE). Athletes, however, may use glycerol to mask the presence of forbidden substances or to enhance performance, inclusively through hyperhydration achieved by glycerol ingestion with added fluid. These practices are considered doping, and are prohibited by the World Anti-Doping Agency (WADA). Therefore, glycerol was introduced in the prohibited list. Doping through glycerol ingestion can readily be identified by detection of elevated glycerol concentrations in urine. In this paper, a protocol for the fast detection of glycerol in urine is proposed. It consists of a previous visual colourimetric screening, followed by a quantitative/qualitative confirmation analysis by mass spectrometry. The screening procedure involves a reaction in which polyhydric alcohols are oxidized by periodate to formic acid and formaldehyde, which is detected by the addition of a fuchsin solution. For the subsequent qualitative/quantitative confirmation analysis, a gas chromatography-mass spectrometry based approach with a non-deuterated internal standard and a drying step of only 10 min is proposed. The linear correlation was demonstrated within WADA´s threshold range. The calculated RSD were 2.1% for within-day precision and 2.8% for between-day precision. The uncertainty estimation was calculated, and a value of 2.7% was obtained. The procedure may also be used for the analysis of other polyols in urine, as for example the PVE mannitol. PMID:26112364

  1. Molecular Characterization of the Glycerol-Oxidative Pathway of Clostridium butyricum VPI 1718 ▿

    PubMed Central

    Raynaud, Céline; Lee, Jieun; Sarçabal, Patricia; Croux, Christian; Meynial-Salles, Isabelle; Soucaille, Philippe

    2011-01-01

    The glycerol oxidative pathway of Clostridium butyricum VPI 1718 plays an important role in glycerol dissimilation. We isolated, sequenced, and characterized the region coding for the glycerol oxidation pathway. Five open reading frames (ORFs) were identified: dhaR, encoding a putative transcriptional regulator; dhaD (1,142 bp), encoding a glycerol dehydrogenase; and dhaK (995 bp), dhaL (629 bp), and dhaM (386 bp), encoding a phosphoenolpyruvate (PEP)-dependent dihydroxyacetone (DHA) kinase enzyme complex. Northern blot analysis demonstrated that the last four genes are transcribed as a 3.2-kb polycistronic operon only in glycerol-metabolizing cultures, indicating that the expression of this operon is regulated at the transcriptional level. The transcriptional start site of the operon was determined by primer extension, and the promoter region was deduced. The glycerol dehydrogenase activity of DhaD and the PEP-dependent DHA kinase activity of DhaKLM were demonstrated by heterologous expression in different Escherichia coli mutants. Based on our complementation experiments, we proposed that the HPr phosphoryl carrier protein and His9 residue of the DhaM subunit are involved in the phosphoryl transfer to dihydroxyacetone-phosphate. DhaR, a potential regulator of this operon, was found to contain conserved transmitter and receiver domains that are characteristic of two-component systems present in the AraC family. To the best of our knowledge, this is the first molecular characterization of a glycerol oxidation pathway in a Gram-positive bacterium. PMID:21478343

  2. The effects of a protein osmolyte on the stability of the integral membrane protein glycerol facilitator.

    PubMed

    Baturin, Simon; Galka, Jamie J; Piyadasa, Hadeesha; Gajjeraman, S; O'Neil, Joe D

    2014-12-01

    Osmolytes are naturally occurring molecules used by a wide variety of organisms to stabilize proteins under extreme conditions of temperature, salinity, hydrostatic pressure, denaturant concentration, and desiccation. The effects of the osmolyte trimethylamine N-oxide (TMAO) as well as the influence of detergent head group and acyl chain length on the stability of the Escherichia coli integral membrane protein glycerol facilitator (GF) tetramer to thermal and chemical denaturation by sodium dodecyl sulphate (SDS) are reported. TMAO promotes the association of the normally tetrameric α-helical protein into higher order oligomers in dodecyl-maltoside (DDM), but not in tetradecyl-maltoside (TDM), lyso-lauroylphosphatidyl choline (LLPC), or lyso-myristoylphosphatidyl choline (LMPC), as determined by dynamic light scattering (DLS); an octameric complex is particularly stable as indicated by SDS polyacrylamide gel electrophoresis. TMAO increases the heat stability of the GF tetramer an average of 10 °C in the 4 detergents and also protects the protein from denaturation by SDS. However, it did not promote re-association to the tetramer when added to SDS-dissociated protein. TMAO also promotes the formation of rod-like detergent micelles, and DLS was found to be useful for monitoring the structure of the protein and the redistribution of detergent during thermal dissociation of the protein. The protein is more thermally stable in detergents with the phosphatidylcholine head group (LLPC and LMPC) than in the maltoside detergents. The implications of the results for osmolyte mechanism, membrane protein stability, and protein-protein interactions are discussed. PMID:25387032

  3. Studies on spectroscopy of glycerol in THz range using microfluidic chip-integrated micropump

    NASA Astrophysics Data System (ADS)

    Su, Bo; Han, Xue; Wu, Ying; Zhang, Cunlin

    2014-11-01

    Terahertz time-domain spectroscopy (THz-TDS) is a detection method of biological molecules with label-free, non-ionizing, non-intrusive, no pollution and real-time monitoring. But owing to the strong THz absorption by water, it is mainly used in the solid state detection of biological molecules. In this paper, we present a microfluidic chip technique for detecting biological liquid samples using the transmission type of THz-TDS system. The microfluidic channel of the microfluidic chip is fabricated in the quartz glass using Micro-Electro-Mechanical System (MEMS) technology and sealed with polydimethylsiloxane (PDMS) diaphragm. The length, width and depth of the microfluidic channel are 25mm, 100μm and 50μm, respectively. The diameter of THz detection zone in the microfluidic channel is 4mm. The thicknesses of quartz glass and PDMS diaphragm are 1mm and 250μm, individually. Another one of the same quartz glass is used to bond with the PDMS for the rigidity and air tightness of the microfluidic chip. In order to realize the automation of sampling and improve the control precise of fluid, a micropump, which comprises PDMS diaphragm, pump chamber, diffuser and nozzle and flat vibration motor, is integrated on the microfluidic chip. The diffuser and nozzle are fabricated on both sides of the pump chamber, which is covered with PDMS diaphragm. The flat vibration motor is stuck on the PDMS diaphragm as the actuator. We study the terahertz absorption spectroscopy characteristics of glycerol with the concentration of 98% in the microfluidic chip by the aid of the THz-TDS system, and the feasibility of the microfluidic chip for the detection of liquid samples is proved.

  4. Inhibition of apolipoprotein B and triglyceride secretion in human hepatoma cells (HepG2).

    PubMed

    Haghpassand, M; Wilder, D; Moberly, J B

    1996-07-01

    Apolipoprotein B (apoB), the major protein component of triglyceride-rich lipoproteins, is assembled into a lipoprotein particle via a complex, multistep process. Recent studies indicate that triglyceride-rich lipoprotein assembly requires the activity of the heterodimeric protein, microsomal triglyceride transfer protein (MTP). We identified a novel inhibitor of apolipoprotein B secretion using the human hepatoma cell line, HepG2. CP-10447, a derivative of the hypnotic drug methaqualone (Quaalude), inhibited apoB secretion from HepG2 cells with an IC50 of approximately 5 microM. CP-10447 also inhibited apoB secretion from Caco-2 cells, a model of intestinal lipoprotein production. In experiments using [3H]glycerol as a precursor for triglyceride synthesis, CP-10447 (20 microM) inhibited radiolabeled triglyceride secretion by approximately 83% (P < 0.0001) in HepG2 cells and 76% (P < 0.05) in Caco-2 cells with no effect on radiolabel incorporation into cellular triglyceride, indicating that CP-10447 inhibited triglyceride secretion without affecting triglyceride synthesis. RNA solution hybridization assay indicated that CP-10447 did not affect apoB or apoA-I mRNA levels. Pulse-chase experiments in HepG2 cells confirmed that CP-10447 inhibited the secretion of apoB (not its synthesis) without affecting secretion of total proteins or albumin and suggested that CP-10447 stimulates the early intracellular degradation of apoB in the endoplasmic reticulum (ER). Further studies demonstrated that CP-10447 is a potent inhibitor of human liver microsomal triglyceride transfer activity (IC50 approximately 1.7 microM) in an in vitro assay containing artificial liposomes and partially purified human MTP. These data suggest that CP-10447 may inhibit apoB and triglyceride secretion by inhibiting MTP activity and stimulating the early ER degradation of apoB. CP-10447 should provide a useful tool for further study of the mechanisms of apoB secretion and triglyceride

  5. News Note: Tracking Secret Satellite

    NASA Astrophysics Data System (ADS)

    Roberts, Greg

    2015-06-01

    The fourth flight of the secret US Air Force mini-shuttle, also known as the X-37B or OTV-4 (Orbital Test Vehicle) was launched by ULA (United Launch Alliance) atop an ATLAS V rocket from Cape Canaveral on the 20th May 2015 at 15.05UT. This article describes amateur efforts to find its orbit.

  6. The secret of the universe.

    NASA Astrophysics Data System (ADS)

    Asimov, I.

    The author turns his attention to such questions as: How near is the nearest star? How heavy is the Sun? How does the Doppler effect work? and countless others. In addition, he provides an explanation of how mankind first became engaged in business and commerce, and advances his own unique theory on the secret of the universe.

  7. FOIA: What's a Trade Secret?

    ERIC Educational Resources Information Center

    Hawker, Curtis

    The Freedom of Information Act (FOIA) was amended in 1974 in order to restrict government control and to facilitate the public's access to information. However, part of the FOIA bans federal officials from disclosing "trade secrets" and commercial or financial information obtained in confidential circumstances. This exemption has resulted in a…

  8. Electroactive biodegradable polyurethane significantly enhanced Schwann cells myelin gene expression and neurotrophin secretion for peripheral nerve tissue engineering.

    PubMed

    Wu, Yaobin; Wang, Ling; Guo, Baolin; Shao, Yongpin; Ma, Peter X

    2016-05-01

    Myelination of Schwann cells (SCs) is critical for the success of peripheral nerve regeneration, and biomaterials that can promote SCs' neurotrophin secretion as scaffolds are beneficial for nerve repair. Here we present a biomaterials-approach, specifically, a highly tunable conductive biodegradable flexible polyurethane by polycondensation of poly(glycerol sebacate) and aniline pentamer, to significantly enhance SCs' myelin gene expression and neurotrophin secretion for peripheral nerve tissue engineering. SCs are cultured on these conductive polymer films, and the biocompatibility of these films and their ability to enhance myelin gene expressions and sustained neurotrophin secretion are successfully demonstrated. The mechanism of SCs' neurotrophin secretion on conductive films is demonstrated by investigating the relationship between intracellular Ca(2+) level and SCs' myelination. Furthermore, the neurite growth and elongation of PC12 cells are induced by adding the neurotrophin medium suspension produced from SCs-laden conductive films. These data suggest that these conductive degradable polyurethanes that enhance SCs' myelin gene expressions and sustained neurotrophin secretion perform great potential for nerve regeneration applications. PMID:26897537

  9. Fluxes and distribution of intact glycerol dialkyl glycerol tetraether membrane lipids in the water column of Lake Challa, East Africa

    NASA Astrophysics Data System (ADS)

    Weijers, J.; Buckles, L.; Verschuren, D.; Sinninghe Damsté, J. S.

    2009-12-01

    Over the last years, glycerol dialkyl glycerol tetraether (GDGT) membrane lipids have become an interesting tool in palaeoclimate research. Both the TEX86 sea surface temperature proxy, based on isoprenoid GDGT membrane lipids derived from pelagic Crenarchaeota, and the MBT/CBT annual mean air temperature proxy, based on the distribution of branched GDGTs derived from soil bacteria, receive increasing interest to be also applied in lake sediments. Despite successful studies utilizing the TEX86 to reconstruct past lake surface temperatures in two large African lakes, other studies indicated that TEX86 values derived from lake surface sediments differed from what would be expected based on the lake surface water temperatures. In addition, in two tropical lake systems, the distribution of branched GDGT lipids in lake surface sediments appeared to differ from that in the surrounding soils. Both situations suggest production of GDGTs by additional sources in some lake systems, hampering application of earlier mentioned temperature proxies. In order to constrain the provenance and flux of GDGT lipids in one of these lakes, Lake Challa, a freshwater crater lake in East Africa, we used a novel separation technique to analyze both intact and core GDGT membrane lipids in monthly samples derived from a sediment trap installed at 35m depth in the lake. Intact GDGT lipids still contain a functional polar head group which is thought to be lost quickly after cell lysis. Therefore, the presence of such intact GDGT lipids is thought indicative for extant life, most likely autochthonous in origin. High fluxes of intact GDGT-0 lipids, maybe derived from methanogenic Archaea residing in anoxic micro niches in descending particles, occur in July and August during a diatom bloom. High fluxes of both the intact and core isoprenoid GDGT lipid crenarchaeol in December and January clearly reflect the bloom of Crenarchaeota. TEX86 values of both the intact and core isoprenoid GDGTs are

  10. Occurrence and abundance of 6-methyl branched glycerol dialkyl glycerol tetraethers in soils: Implications for palaeoclimate reconstruction

    NASA Astrophysics Data System (ADS)

    De Jonge, Cindy; Hopmans, Ellen C.; Zell, Claudia I.; Kim, Jung-Hyun; Schouten, Stefan; Sinninghe Damsté, Jaap S.

    2014-09-01

    The distribution of branched glycerol dialkyl glycerol tetraethers (brGDGTs) in soils has been shown to correlate with the soil pH and the mean annual air temperature (MAT). This has been used to perform palaeoclimate reconstructions based on brGDGTs recovered from palaeosoils, freshwater, and marine sedimentary archives. Recently described 6-methyl brGDGTs were shown to co-elute with the 5-methyl brGDGTs that are used to calculate the CBT and MBT‧ indices used as palaeoclimate proxies. The impact of these 6-methyl brGDGTs on the established palaeoclimate proxies is unknown and will depend on their abundance in soils. Using improved chromatography, we quantified the fractional abundance of 6-methyl brGDGTs in globally distributed soils and show that they are abundant components, comprising on average 24% of the total amount of brGDGTs. All penta- and hexa-methylated brGDGTs (i.e. with zero to two cyclopentane moieties) were shown to comprise both 5- and 6-methyl isomers. The fractional abundances of the six 6-methyl brGDGTs correlate positively with each other, suggesting a common biological source in most soils, and correlate strongly with soil pH. The presence of the 6-methyl brGDGTs introduced scatter in the original MBT‧/CBT-MAT calibration and caused a dependence on soil pH of the MBT‧. Exclusion of the 6-methyl brGDGTs from the MBT‧, i.e. the newly defined MBT‧5ME, shows that it is no longer related to soil pH. The correlation with MAT is improved, reducing the residual mean error (RMSE) from 6.2 to 4.8 °C. Also, the correlation of the CBT after the exclusion of the 6-methyl brGDGTs (defined as CBT5ME) with soil pH slightly improved. Furthermore, the separate quantification of the 6-methyl brGDGTs allows the definition of new indices. The CBT‧, which comprises the 6-methyl brGDGTs, is a substantially improved alternative to the CBT5ME, reducing the RMSE from 0.8 to 0.5 pH units. Also, the accuracy of MAT reconstructions can be improved using a

  11. Enzymes of Glycerol and Glyceraldehyde Metabolism in Mouse Liver: Effects of Caloric Restriction and Age on Activities

    PubMed Central

    Hagopian, Kevork; Ramsey, Jon J.; Weindruch, Richard

    2008-01-01

    Synopsis The influence of caloric restriction on hepatic glyceraldehyde and glycerol metabolizing enzyme activities of young and old mice were studied. Glycerol kinase and cytoplasmic glycerol-3-phosphate dehydrogenase activities were increased in both young and old CR mice when compared to controls, while triokinase increased only in old CR mice. Aldehyde dehydrogenase and aldehyde reductase activities in both young and old CR were unchanged by CR. Mitochondrial glycerol-3-phosphate dehydrogenase showed a trend towards an increased activity in old CR mice, while a trend towards a decreased activity in alcohol dehydrogenase was observed in both young and old CR mice. Serum glycerol levels decreased in young and old CR mice. Therefore, increases in glycerol kinase and glycerol-3-phosphate dehydrogenase were associated with a decrease in fasting blood glycerol levels in CR animals. A prominent role for triokinase in glyceraldehyde metabolism with CR was also observed. The results indicate that long-term CR induces sustained increases in the capacity for gluconeogenesis from glycerol. PMID:18429748

  12. Effect of impurities in biodiesel-derived waste glycerol on the performance and feasibility of biotechnological processes.

    PubMed

    Chatzifragkou, Afroditi; Papanikolaou, Seraphim

    2012-07-01

    The rapid development of biodiesel production technology has led to the generation of tremendous quantities of glycerol wastes, as the main by-product of the process. Stoichiometrically, it has been calculated that for every 100 kg of biodiesel, 10 kg of glycerol are produced. Based on the technology imposed by various biodiesel plants, glycerol wastes may contain numerous kinds of impurities such as methanol, salts, soaps, heavy metals, and residual fatty acids. This fact often renders biodiesel-derived glycerol unprofitable for further purification. Therefore, the utilization of crude glycerol though biotechnological means represents a promising alternative for the effective management of this industrial waste. This review summarizes the effect of various impurities-contaminants that are found in biodiesel-derived crude glycerol upon its conversion by microbial strains in biotechnological processes. Insights are given concerning the technologies that are currently applied in biodiesel production, with emphasis to the impurities that are added in the composition of crude glycerol, through each step of the production process. Moreover, extensive discussion is made in relation with the impact of the nature of impurities upon the performances of prokaryotic and eukaryotic microorganisms, during crude glycerol bioconversions into a variety of high added-value metabolic products. Finally, aspects concerning ways of crude glycerol treatment for the removal of inhibitory contaminants as reported in the literature are given and comprehensively discussed. PMID:22581036

  13. Seven Simple Secrets: What the Best Teachers Know and Do!

    ERIC Educational Resources Information Center

    Breaux, Annette L.; Whitaker, Todd

    2006-01-01

    Implementing the secrets presented in this book will change your life both in and out of the classroom. But most importantly, implementing these secrets will enhance the lives of every student you teach. The following are contained in this book: Secret One: The Secret of Planning; Secret Two: The Secret of Classroom Management; Secret Three: The…

  14. A novel multigene expression construct for modification of glycerol metabolism in Yarrowia lipolytica

    PubMed Central

    2013-01-01

    Background High supply of raw, residual glycerol from biodiesel production plants promote the search for novel biotechnological methods of its utilization. In this study we attempted modification of glycerol catabolism in a nonconventional yeast species Yarrowia lipolytica through genetic engineering approach. Results To address this, we developed a novel genetic construct which allows transferring three heterologous genes, encoding glycerol dehydratase, its reactivator and a wide-spectrum alcohol oxidoreductase under the control of glycerol-induced promoter. The three genes, tandemly arrayed in an expression cassette with a marker gene ura3, regulatory and targeting sequences (G3P dh promoter and XPR-like terminator, 28S rDNA as a target locus), were transferred into Yarrowia lipolytica cells. The obtained recombinant strain NCYC3825 was characterized at the molecular level and with respect to its biotechnological potential. Our experiments indicated that the novel recombinant strain stably borne one copy of the expression cassette and efficiently expressed heterologous alcohol oxidoreductase, while glycerol dehydratase and its reactivator were expressed at lower level. Comparative shake flask cultivations in glucose- and glycerol-based media demonstrated higher biomass production by the recombinant strain when glycerol was the main carbon source. During bioreactor (5 L) fed-batch cultivation in glycerol-based medium, the recombinant strain was characterized by relatively high biomass and lipids accumulation (up to 42 gDCW L-1, and a peak value of 38%LIPIDS of DCW, respectively), and production of high titers of citric acid (59 g L-1) and 2-phenylethanol (up to 1 g L-1 in shake flask cultivation), which are industrially attractive bioproducts. Conclusions Due to heterogeneous nature of the observed alterations, we postulate that the main driving force of the modified phenotype was faster growth in glycerol-based media, triggered by modifications in the red

  15. Use of raw glycerol to produce oil rich in polyunsaturated fatty acids by a thraustochytrid.

    PubMed

    Scott, Spencer D; Armenta, Roberto E; Berryman, Kevin T; Norman, Andrew W

    2011-03-01

    Glucose is the typical carbon source for producing microbial polyunsaturated fatty acids (PUFA) with single cell microorganisms such as thraustochytrids. We assessed the use of a fish oil derived glycerol by-product (raw glycerol), produced by a fish oil processing plant, as a carbon source to produce single cell oil rich in polyunsaturated fatty acids (PUFA), notably docosahexaenoic acid (DHA). These results were compared to those obtained when using analytical grade glycerol, and glucose. The thraustochytrid strain tested produced similar amounts of oil and PUFA when grown with both types of glycerol, and results were also similar to those obtained using glucose. After 6 days of fermentation, approximately 320 mg/g of oil, and 145 mg/g of PUFA were produced with all carbon sources tested. All oils produced by our strain were 99.95% in the triacylglycerol form. To date, this is the first report of using raw glycerol derived from fish oil for producing microbial triglyceride oil rich in PUFA. PMID:22112910

  16. Glycerol-Induced Membrane Stiffening: The Role of Viscous Fluid Adlayers

    PubMed Central

    Pocivavsek, Luka; Gavrilov, Kseniya; Cao, Kathleen D.; Chi, Eva Y.; Li, Dongxu; Lin, Binhua; Meron, Mati; Majewski, Jaroslaw; Lee, Ka Yee C.

    2011-01-01

    Lipid interfaces, ranging from cell membranes to thin surfactant layers that stabilize lung alveoli, are integral to living systems. Such interfaces are often subjected to mechanical forces, and because of their membrane-like geometry, they can easily deform by bending into localized folds. In this work, we explore the role of small molecules (i.e., glycerol) on the mechanical stability of model lung surfactant monolayers. We demonstrate that the presence of glycerol increases local monolayer bending stiffness by orders of magnitude. Our x-ray and neutron reflectivity measurements indicate that water is preferentially depleted, or glycerol is preferentially enriched, at the lipid headgroup/solvent interface, and that this glycerol-enriched layer extends O(10Å) beneath the monolayer with an adsorption free energy of −2.5 to −4.6 kJ/mol. The dramatic change in membrane bending stiffness in the presence of the sugar adlayer is understood in terms of two models: 1), lipid antiplasticization by glycerol; and 2), a continuum mechanical model of the viscous adlayer. PMID:21723821

  17. Biochemical and molecular characterization of the oxidative branch of glycerol utilization by Citrobacter freundii.

    PubMed Central

    Daniel, R; Stuertz, K; Gottschalk, G

    1995-01-01

    Glycerol dehydrogenase (EC 1.1.1.6) and dihydroxyacetone kinase (EC 2.7.1.29) were purified from Citrobacter freundii. The dehydrogenase is a hexamer of a polypeptide of 43,000 Da. The enzyme exhibited a rather broad substrate specificity, but glycerol was the preferred substrate in the physiological direction. The apparent Kms of the enzyme for glycerol and NAD+ were 1.27 mM and 57 microM, respectively. The kinase is a dimer of a polypeptide of 57,000 Da. The enzyme was highly specific for the substrates dihydroxyacetone and ATP; the apparent Kms were 30 and 70 microM, respectively. The DNA region which contained the genes encoding glycerol dehydrogenase (dhaD) and dihydroxyacetone kinase (dhaK) was cloned and sequenced. Both genes were identified by N-terminal sequence comparison. The deduced dhaD gene product (365 amino acids) exhibited high degrees of homology to glycerol dehydrogenases from other organisms and less homology to type III alcohol dehydrogenases, whereas the dhaK gene product (552 amino acids) revealed no significant homology to any other protein in the databases. A large gene (dhaR) of 1,929 bp was found downstream from dhaD. The deduced gene product (641 amino acids) showed significant similarities to members of the sigma 54 bacterial enhancer-binding protein family. PMID:7635824

  18. Glycerol as a substrate for aerobic succinate production in minimal medium with Corynebacterium glutamicum

    PubMed Central

    Litsanov, Boris; Brocker, Melanie; Bott, Michael

    2013-01-01

    Corynebacterium glutamicum, an established microbial cell factory for the biotechnological production of amino acids, was recently genetically engineered for aerobic succinate production from glucose in minimal medium. In this work, the corresponding strains were transformed with plasmid pVWEx1-glpFKD coding for glycerol utilization genes from Escherichia coli. This plasmid had previously been shown to allow growth of C. glutamicum with glycerol as sole carbon source. The resulting strains were tested in minimal medium for aerobic succinate production from glycerol, which is a by-product in biodiesel synthesis. The best strain BL-1/pVWEx1-glpFKD formed 79 mM (9.3 g l−1) succinate from 375 mM glycerol, representing 42% of the maximal theoretical yield under aerobic conditions. A specific succinate production rate of 1.55 mmol g−1 (cdw) h−1 and a volumetric productivity of 3.59 mM h−1 were obtained, the latter value representing the highest one currently described in literature. The results demonstrate that metabolically engineered strains of C. glutamicum are well suited for aerobic succinate production from glycerol. PMID:22513227

  19. Biotechnological conversion of glycerol from biofuels to 1,3-propanediol using Escherichia coli.

    PubMed

    Przystałowska, Hanna; Lipiński, Daniel; Słomski, Ryszard

    2015-01-01

    In the face of shortage of fossil fuel supplies and climate warming triggered by excessive carbon dioxide emission, alternative resources for chemical industry have gained considerable attention. Renewable resources and their derivatives are of particular interest. Glycerol, which constitutes one of the by-products during biodiesel production, is such a substrate. Thus, generated excess glycerol may become an environmental problem, since it cannot be disposed of in the environment. The most promising products obtained from glycerol are polyols, including 1,3-propanediol, an important substrate in the production of synthetic materials, e.g. polyurethanes, unsaturated polyesters, and epoxy resins. Glycerol can be used as a carbon and energy source for microbial growth in industrial microbiology to produce 1,3-propanediol. This paper is a review of metabolic pathways of native producers and E. coli with the acquired ability to produce the diol via genetic manipulations. Culture conditions during 1,3-PDO production and genetic modifications of E. coli used in order to increase efficiency of glycerol bioconversion are also described in this paper. PMID:25710056

  20. Optimization of cultural conditions for conversion of glycerol to ethanol by Enterobacter aerogenes S012.

    PubMed

    Nwachukwu, Raymond E S; Shahbazi, Abolghasem; Wang, Lijun; Worku, Mulumebet; Ibrahim, Salam; Schimmel, Keith

    2013-01-01

    The aim of this research is to optimize the cultural conditions for the conversion of glycerol to ethanol by Enterobacter aerogenes S012. Taguchi method was used to screen the cultural conditions based on their signal to noise ratio (SN). Temperature (°C), agitation speed (rpm) and time (h) were found to have the highest influence on both glycerol utilization and ethanol production by the organism while pH had the lowest. Full factorial design, statistical analysis, and regression model equation were used to optimize the selected cultural parameters for maximum ethanol production. The result showed that fermentation at 38°C and 200 rpm for 48 h would be ideal for the bacteria to produce maximum amount of ethanol from glycerol. At these optimum conditions, ethanol production, yield and productivity were 25.4 g/l, 0.53 g/l/h, and 1.12 mol/mol-glycerol, repectively. Ethanol production increased to 26.5 g/l while yield and productivity decreased to 1.04 mol/mol-glycerol and 0.37 g/l/h, respectively, after 72 h. Analysis of the fermentation products was performed using HPLC, while anaerobic condition was created by purging the fermentation vessel with nitrogen gas. PMID:23388539

  1. Two glycerol uptake systems contribute to the high osmotolerance of Zygosaccharomyces rouxii.

    PubMed

    Dušková, Michala; Ferreira, Célia; Lucas, Cândida; Sychrová, Hana

    2015-08-01

    The accumulation of glycerol is essential for yeast viability upon hyperosmotic stress. Here we show that the osmotolerant yeast Zygosaccharomyces rouxii has two genes, ZrSTL1 and ZrSTL2, encoding transporters mediating the active uptake of glycerol in symport with protons, contributing to cell osmotolerance and intracellular pH homeostasis. The growth of mutants lacking one or both transporters is affected depending on the growth medium, carbon source, strain auxotrophies, osmotic conditions and the presence of external glycerol. These transporters are localised in the plasma membrane, they transport glycerol with similar kinetic parameters and besides their expected involvement in the cell survival of hyperosmotic stress, they surprisingly both contribute to an efficient survival of hypoosmotic shock and to the maintenance of intracellular pH homeostasis under non-stressed conditions. Unlike STL1 in Sa. cerevisiae, the two Z. rouxii STL genes are not repressed by glucose, but their expression and activity are downregulated by fructose and upregulated by non-fermentable carbon sources, with ZrSTL1 being more influenced than ZrSTL2. In summary, both transporters are highly important, though Z. rouxii CBS 732(T) cells do not use external glycerol as a source of carbon. PMID:25943012

  2. Anaerobic pathways of glycerol dissimilation by Enterobacter agglomerans CNCM 1210: limitations and regulations.

    PubMed

    Barbirato, F; Astruc, S; Soucaille, P; Camarasa, C; Salmon, J M; Bories, A

    1997-07-01

    Continuous cultures of Enterobacter agglomerans CNCM 1210 were performed under regulated pH conditions (pH 7.0) with glycerol or glucose (20 g l-1) as carbon source. Cultures grown on glucose produced mainly acetate, ethanol and formate. In contrast, 1,3-propanediol (PPD) was the main product with glycerol. The carbon flow distribution at branching metabolic points was investigated. Higher PPD yields with increased dilution rate were correlated with an important increase in the relative ratio of glycerol dehydratase to glycerol dehydrogenase. Determination of intracellular triose-phosphate and fructose 1,6-biphosphate concentrations demonstrated that glyceraldehyde-3-phosphate dehydrogenase is the limiting step in glycerol dissimilation. At the pyruvate branching point, pyruvate dehydrogenase (PDH) activity was systematically detected. The pyruvate flow shifted to PDH is suspected to represent up to 22% of the acetyl-CoA formed. In addition, this enzyme pattern combined with the enhanced in vivo lactate dehydrogenase activity at high growth rates, was correlated with a decrease in the pyruvate formate-lyase activity. A regulation of this latter enzyme by the accumulation of triose-phosphate is suspected. PMID:9245823

  3. Glycerol and urea can be used to increase skin permeability in reduced hydration conditions.

    PubMed

    Björklund, Sebastian; Engblom, Johan; Thuresson, Krister; Sparr, Emma

    2013-12-18

    The natural moisturizing factor (NMF) is a group of hygroscopic molecules that is naturally present in skin and protects from severe drying. Glycerol and urea are two examples of NMF components that are also used in skin care applications. In the present study, we investigate the influence of glycerol and urea on the permeability of a model drug (metronidazole, Mz) across excised pig skin membranes at different hydrating conditions. The degree of skin hydration is regulated by the gradient in water activity across the membrane, which in turn depends on the water activity of the formulation in contact with the skin membrane. Here, we determine the water activity of all formulations employed using an isothermal calorimetric method. Thus, the gradient in water activity is controlled by a novel experimental set-up with well-defined boundary conditions on both sides of the skin membrane. The results demonstrate that glycerol and urea can retain high steady state flux of Mz across skin membranes at dehydrating conditions, which otherwise would decrease the permeability due to dehydration. X-ray diffraction measurements are performed to give insight into the effects of glycerol and urea on SC molecular organization. The novel steady state flux results can be related to the observation that water, glycerol, and urea all affect the structural features of the SC molecular components in a similar manner. PMID:23643739

  4. Determination of esters in glycerol phase after transesterification of vegetable oil.

    PubMed

    Hájek, Martin; Skopal, Frantisek; Kwiecien, Jirí; Cernoch, Michal

    2010-06-30

    In biodiesel production, glycerol is formed as a side product and it is contained in the glycerol phase. This phase contains (besides glycerol): water, soaps, alcohol, traces of catalyst and glycerides and the remaining esters. In this paper, a new method for the determination of esters in the glycerol phase is introduced. The determination enables the minimization of the losses of biodiesel within the production process. It is based on the gradient RP-LC method (water and acetonitrile) with refractometric detection. The analysis is easy and the samples do not need any treatment (only dilution by water) and has a low detection limit. The results of this method were compared with the results of two other published methods: isocratic HPLC and GC. The disadvantage of these two methods is that they need extensive treatment of the sample, which takes many hours, and they are able to determine only the sum of esters. The new method is reliable, much faster and able to differentiate esters of almost each higher fatty acid (e.g. linoleic, linolenic, strearic alkyl ester) in the glycerol phase. PMID:20685468

  5. Glycerol electro-oxidation on a carbon-supported platinum catalyst at intermediate temperatures

    NASA Astrophysics Data System (ADS)

    Ishiyama, Keisuke; Kosaka, Fumihiko; Shimada, Iori; Oshima, Yoshito; Otomo, Junichiro

    2013-03-01

    The electro-oxidation of glycerol on a carbon-supported platinum catalyst (Pt/C) in combination with a reaction products analysis was investigated at intermediate temperatures (235-260 °C) using a single cell with a CsH2PO4 proton conducting solid electrolyte. A high current density was achieved. The main products were H2, CO2 and CO but the formation of C2 compounds, such as glycolic acid and ethane, was also observed. In addition, several C3 compounds were detected as minor products. A reaction products analysis revealed that the C-C bond dissociation ratio of glycerol was 70-80% at both low and high potentials (>200 mV vs. reversible hydrogen electrode) at 250 °C, suggesting that rapid dissociation occurs on Pt/C. The reaction products analysis also suggested that hydrogen production via thermal decomposition and/or steam reforming of glycerol (indirect path) and direct electro-oxidation of glycerol (direct path) proceed in parallel. More detailed reaction paths involving C1, C2 and C3 reaction products are discussed as well as the possible rate-determining step in glycerol electro-oxidation at intermediate temperatures.

  6. Effect of glycerol on a diacetone acrylamide-based holographic photopolymer material.

    PubMed

    Cody, Dervil; Naydenova, Izabela; Mihaylova, Emilia

    2013-01-20

    The composition of the low-toxicity, environmentally compatible diacetone acrylamide (DA) photopolymer has been modified with the inclusion of different additives. The addition of glycerol to the photopolymer composition is described. Results show that the incorporation of glycerol results in a uniform maximum refractive-index modulation for recording intensities in the range of 1-20 mW/cm(2). This may be attributed to glycerol's nature as a plasticizer, which allows for faster diffusion of an unreacted monomer within the grating during holographic recording. An optimum recording intensity of 0.5 mW/cm(2) is observed for exposure energies of 20-60 mW/cm(2). The modified photopolymer achieves a refractive-index modulation of 2.2×10(-3), with diffraction efficiencies up to 90% in 100 μm layers. Glycerol has also shown to reduce the rate of photobleaching of the DA photopolymer. This is possibly due to more prevalent inhibition effects caused by increased oxygenation of the photopolymer layers. The stability of the photopolymer samples is also improved with the addition of glycerol. PMID:23338198

  7. Micron-sized structure in a thin glycerol film revealed by fluorescent probes.

    PubMed

    Xia, Ted; Xiao, Liantuan; Orrit, Michel

    2009-12-01

    We report on micrometer-sized structures in supercooled glycerol observed by imaging fluorescent probes at the temperatures close to, but above, the glass transition temperature (190 K). Two distinct heterogeneous patterns of the fluorescence intensity were detected, depending on how fast the sample was cooled down. In a slowly cooled sample, we observed a Swiss cheese-like pattern in which many micrometer-sized dark spots were nucleated in a bright background. A quickly cooled sample resulted in a spinodal decomposition pattern where many bright island-like features on micrometer scale were dispersed in a dark matrix. Similar patterns were seen earlier in triphenyl phosphite, another molecular liquid, which shows solid-like behavior at temperatures above its glass transition. Once the heterogeneous patterns are formed in the glycerol, they can persist for days, unless the samples are heated above 260 K for more than 10 h. Such heterogeneous patterns are ascribed to differential dye distributions in the glycerol film, pointing to long-lived and micrometer-scale density fluctuations in supercooled glycerol. The observation of such heterogeneity may provide additional understanding on how supercooled glycerol behaves before it turns into a glass. PMID:19929008

  8. Energy balance of biofuel production from biological conversion of crude glycerol.

    PubMed

    Zhang, Xiaolei; Yan, Song; Tyagi, Rajeshwar D; Surampalli, Rao Y; Valéro, Jose R

    2016-04-01

    Crude glycerol, a by-product of biodiesel production, has gained significant attention as a carbon source for biofuel production. This study evaluated the energy balance of biodiesel, hydrogen, biogas, and ethanol production from 3.48 million L of crude glycerol (80% w/v). The conversion efficiency (energy output divided by energy invested) was 1.16, 0.22, 0.27, and 0.40 for the production of biodiesel, hydrogen, biogas, and ethanol respectively. It was found that the use of crude glycerol for biodiesel production was an energy gain process, with a positive energy balance and conversion efficiency of greater than 1. The energy balance revealed a net energy gain of 5226 GJ per 1 million kg biodiesel produced. Production of hydrogen, biogas and ethanol from crude glycerol were energy loss processes. Therefore, the conversion of crude glycerol to lipids and subsequently to biodiesel is suggested to be a better option compared to hydrogen, biogas, or ethanol production with respect to energy balance. PMID:26829450

  9. Gelatinization and retrogradation phenomena in starch/montmorillonite nanocomposites plasticized with different glycerol/water ratios.

    PubMed

    Lara, Sandra Camila; Salcedo, Felipe

    2016-10-20

    This study aims to gain insights into the intermolecular interactions present in thermoplastic starch (TPS)/montmorillonite (MMT) nanocomposites prepared using water and/or glycerol as plasticizers. Specifically, the impact of using different glycerol/water proportions on the nature of gelatinization and retrogradation processes is studied. Nanocomposites were characterized by rheometry, scanning electron microscopy (SEM) and X-rays diffraction (XRD). It is shown that clay tactoids preferentially interact with glycerol molecules rather than starch macromolecules. Consequently, the effects of MMT incorporation strongly depend on the glycerol/water ratio; when a ratio of 0.5 is used minor variations were observed on the starch gelatinization process-although stronger clays-starch interactions were evident-whereas at higher ratios the addition of clays significantly increased the gelatinization temperature, up to values over 100°C. In the gelatinization process of starch in TPS samples having only glycerol as a plasticizer, the leaching of amylose and the melting of amylopectin crystalline domains seem to occur simultaneously. This different gelatinization mechanism produces a TPS having a substantially different morphology, which exhibited reduced retrogradation characteristics. PMID:27474559

  10. Optimization of cultural conditions for conversion of glycerol to ethanol by Enterobacter aerogenes S012

    PubMed Central

    2013-01-01

    The aim of this research is to optimize the cultural conditions for the conversion of glycerol to ethanol by Enterobacter aerogenes S012. Taguchi method was used to screen the cultural conditions based on their signal to noise ratio (SN). Temperature (°C), agitation speed (rpm) and time (h) were found to have the highest influence on both glycerol utilization and ethanol production by the organism while pH had the lowest. Full factorial design, statistical analysis, and regression model equation were used to optimize the selected cultural parameters for maximum ethanol production. The result showed that fermentation at 38°C and 200 rpm for 48 h would be ideal for the bacteria to produce maximum amount of ethanol from glycerol. At these optimum conditions, ethanol production, yield and productivity were 25.4 g/l, 0.53 g/l/h, and 1.12 mol/mol-glycerol, repectively. Ethanol production increased to 26.5 g/l while yield and productivity decreased to 1.04 mol/mol-glycerol and 0.37 g/l/h, respectively, after 72 h. Analysis of the fermentation products was performed using HPLC, while anaerobic condition was created by purging the fermentation vessel with nitrogen gas. PMID:23388539

  11. Antioxidant and Nephroprotective Activities of Aconitum heterophyllum Root in Glycerol Induced Acute Renal Failure in Rats

    PubMed Central

    Eerike, Madhavi; Raghuraman, Lakshmipathy Prabhu; Rajamanickam, Maignana Kumar

    2016-01-01

    Aim The present study was to evaluate the antioxidant and nephroprotective activities of ethanolic extract of Aconitum heterophyllum root (EEAHR) in glycerol induced acute renal failure (ARF) in Wistar albino rats. Materials and Methods In vitro antioxidant activity of EEAHR was assessed using the 2, 2-diphenyl-picrylhydrazyl (DPPH assay), nitric oxide radical scavenging (NO assay), hydrogen peroxide (H2O2 assay) and ferric reducing antioxidant power (FRAP) scavenging activity assays. In vivo study, rats were divided into four groups of six each for assessing the nephroprotective activity. Group-1 received normal saline, group-2 received 50% glycerol (10 ml/kg) alone, group-3 received glycerol and 250 mg/kg of EEAHR and group-4 received glycerol and 500 mg/kg of EEAHR. The renal injury and recovery was measured by serum creatinine, blood urea nitrogen (BUN), total proteins, albumin, urine output and histopathological changes. Results In vitro antioxidant activity of root extract was found to be equal to Vitamin C and in an in vivo study root extract treated animals showed significant attenuation of biochemical parameters and histopathological changes of the kidney compared to glycerol treated group and it was found to be more significant with the extract at 500 mg/kg than 250mg/kg. Conclusion The present study revealed that Aconitum heterophyllum root has shown antioxidant and nephroprotective activities. PMID:27134892

  12. Glycerol Is a Suberin Monomer. New Experimental Evidence for an Old Hypothesis1

    PubMed Central

    Moire, Laurence; Schmutz, Alain; Buchala, Antony; Yan, Bin; Stark, Ruth E.; Ryser, Ulrich

    1999-01-01

    The monomer composition of the esterified part of suberin can be determined using gas chromatography-mass spectroscopy technology and is accordingly believed to be well known. However, evidence was presented recently indicating that the suberin of green cotton (Gossypium hirsutum cv Green Lint) fibers contains substantial amounts of esterified glycerol. This observation is confirmed in the present report by a sodium dodecyl sulfate extraction of membrane lipids and by a developmental study, demonstrating the correlated accumulation of glycerol and established suberin monomers. Corresponding amounts of glycerol also occur in the suberin of the periderm of cotton stems and potato (Solanum tuberosum) tubers. A periderm preparation of wound-healing potato tuber storage parenchyma was further purified by different treatments. As the purification proceeded, the concentration of glycerol increased at about the same rate as that of α,ω-alkanedioic acids, the most diagnostic suberin monomers. Therefore, it is proposed that glycerol is a monomer of suberins in general and can cross-link aliphatic and aromatic suberin domains, corresponding to the electron-translucent and electron-opaque suberin lamellae, respectively. This proposal is consistent with the reported dimensions of the electron-translucent suberin lamellae. PMID:10069853

  13. Optimization of 1,3-dihydroxyacetone production from crude glycerol by immobilized Gluconobacter oxydans MTCC 904.

    PubMed

    Dikshit, Pritam Kumar; Moholkar, Vijayanand S

    2016-09-01

    This study has addressed the matter of optimization of production of the value added product, dihydroxyacetone, from crude glycerol using immobilized cells of Gluconobacter oxydans. Statistical optimization of the fermentation medium revealed MgSO4·7H2O, (NH4)2SO4 and KH2PO4 as the significant components, in addition to small concentration of yeast extract. As per previous literature, these components augment the activity of glycerol dehydrogenase enzyme in metabolism and provide assimilable nitrogen and sulfur source for cell growth. Yeast extract not only provides essential growth factors, but also accelerates production of alcohol dehydrogenase enzyme due to amino acids present. The DHA yield from crude glycerol (20g/L) with optimized medium is 14.08g/L, which is just 12% lower than the yield for pure glycerol .This study has thus established that proper optimization of fermentation medium reduces the adverse effect of impurities in crude glycerol on fermentation process and DHA yield. PMID:26873288

  14. Optimization of glycerol fed-batch fermentation in different reactor states: a variable kinetic parameter approach.

    PubMed

    Xie, Dongming; Liu, Dehua; Zhu, Haoli; Zhang, Jianan

    2002-05-01

    To optimize the fed-batch processes of glycerol fermentation in different reactor states, typical bioreactors including 500-mL shaking flask, 600-mL and 15-L airlift loop reactor, and 5-L stirred vessel were investigated. It was found that by reestimating the values of only two variable kinetic parameters associated with physical transport phenomena in a reactor, the macrokinetic model of glycerol fermentation proposed in previous work could describe well the batch processes in different reactor states. This variable kinetic parameter (VKP) approach was further applied to model-based optimization of discrete-pulse feed (DPF) strategies of both glucose and corn steep slurry for glycerol fed-batch fermentation. The experimental results showed that, compared with the feed strategies determined just by limited experimental optimization in previous work, the DPF strategies with VKPs adjusted could improve glycerol productivity at least by 27% in the scale-down and scale-up reactor states. The approach proposed appeared promising for further modeling and optimization of glycerol fermentation or the similar bioprocesses in larger scales. PMID:12049203

  15. Tamper-proof secret image-sharing scheme for identifying cheated secret keys and shared images

    NASA Astrophysics Data System (ADS)

    Chen, Chien-Chang; Liu, Chong-An

    2013-01-01

    A (t,n) secret image-sharing scheme shares a secret image to n participants, and the t users recover the image. During the recovery procedure of a conventional secret image-sharing scheme, cheaters may use counterfeit secret keys or modified shared images to cheat other users' secret keys and shared images. A cheated secret key or shared image leads to an incorrect secret image. Unfortunately, the cheater cannot be identified. We present an exponent and modulus-based scheme to provide a tamper-proof secret image-sharing scheme for identifying cheaters on secret keys or shared images. The proposed scheme allows users to securely select their secret key. This assignment can be performed over networks. Modulus results of each shared image is calculated to recognize cheaters of a shared image. Experimental results indicate that the proposed scheme is excellent at identifying cheated secret keys and shared images.

  16. Secreted proteins as a fundamental source for biomarker discovery

    PubMed Central

    Stastna, Miroslava; Van Eyk, Jennifer E.

    2012-01-01

    The proteins secreted by various cells (the secretomes) are a potential rich source of biomarkers since they reflect various states of the cells at real time and at given conditions. To have accessible, sufficient and reliable protein markers is desirable since they mark various stages of disease development and their presence/absence can be used for diagnosis, prognosis, risk stratification and therapeutic monitoring. As direct analysis of blood/plasma, a common and noninvasive patient screening method, can be difficult for candidate protein biomarker identification, the alternative/complementary approaches are required, one of them is the analysis of secretomes in cell conditioned media in vitro. Since the proteins secreted by cells as a response to various stimuli are most likely secreted into blood/plasma, the identification and preselection of candidate protein biomarkers from cell secretomes with subsequent validation of their presence at higher levels in serum/plasma is a promising approach. In this review, we discuss the proteins secreted by three progenitor cell types (smooth muscle, endothelial and cardiac progenitor cells) and two adult cell types (neonatal rat ventrical myocytes and smooth muscle cells) which can be relevant to cardiovascular research and which have been recently published in the literature. We found, at least for secretome studies included in this review, that secretomes of progenitor and adult cells overlap by 48% but the secretomes are very distinct among progenitor cell themselves as well as between adult cells. In addition, we compared secreted proteins to protein identifications listed in the Human Plasma PeptideAtlas and in two reports with cardiovascular-related proteins and we performed the extensive literature search to find if any of these secreted proteins were identified in a biomarker study. As expected, many proteins have been identified as biomarkers in cancer but 18 proteins (out of 62) have been tested as biomarkers in

  17. Crude Glycerol as Cost-Effective Fuel for Combined Heat and Power to Replace Fossil Fuels, Final Technical Report

    SciTech Connect

    Roberts, William L

    2012-10-31

    The primary objectives of this work can be summed into two major categories. Firstly, the fundamentals of the combustion of glycerol (in both a refined and unrefined form) were to be investigated, with emphasis of the development of a system capable of reliably and repeatedly combusting glycerol as well as an analysis of the emissions produced during glycerol combustion. Focus was placed on quantifying common emissions in comparison to more traditional fuels and this work showed that the burner developed was able to completely combust glycerol within a relatively wide range of operating conditions. Additionally, focus was placed on examining specific emissions in more detail, namely interesting NOx emissions observed in initial trials, acrolein and other volatile organic emissions, and particulate and ash emissions. This work showed that the combustion of crude glycerol could result in significantly reduced NOx emissions as a function of the high fuel bound oxygen content within the glycerol fuel. It also showed that when burned properly, the combustion of crude glycerol did not result in excessive emissions of acrolein or any other VOC compared to the combustion from more traditional fuels. Lastly however, this work has shown that in any practical application in which glycerol is being burned, it will be necessary to explore ash mitigation techniques due to the very high particulate matter concentrations produced during glycerol combustion. These emissions are comparable to unfiltered coal combustion and are directly tied to the biodiesel production method. The second focus of this work was directed to developing a commercialization strategy for the use of glycerol as a fuel replacement. This strategy has identified a 30 month plan for the scaling up of the laboratory scale burner into a pre-pilot scale system. Additionally, financing options were explored and an assessment was made of the economics of replacing a traditional fuel (namely natural gas) with crude

  18. The effect of glycerol-related osmotic changes on post-thaw motility and acrosomal integrity of ram spermatozoa.

    PubMed

    Fiser, P S; Fairfull, R W

    1989-02-01

    Ram semen, collected by artificial vagina, was diluted and processed for long-term storage as described by P. S. Fiser, L. Ainsworth, and R. W. Fairfull (Canad. J. Anim. Sci. 62, 425-428, 1982). The concentration of the cryoprotectant, glycerol, was adjusted to 4% in the diluted semen prior to freezing by a one-step addition at 30 degrees C (Method 1), by cooling the semen to 5 degrees C and addition of the glycerol gradually over 30 min (Method 2), by one-step addition of glycerol prior to equilibration for 2 hr (Method 3), or by cooling to 5 degrees C, followed by a holding period of 2 hr at 5 degrees C, and the one-step addition of glycerol just prior to freezing (Method 4). After thawing, the glycerol concentration of the semen was reduced by stepwise dilution from 4 to 0.4% over 15 or 30 min or by a one-step ten-fold dilution. The average post-thaw percentage of motile spermatozoa was significantly lower after addition of glycerol by Method 1 (39.9%) than when the glycerol was added by the other three methods (range, 44.0-46.4% averaged over the glycerol dilution). The average post-thaw percentage of intact acrosomes (61.2%), highest in semen in which the glycerol was added by Method 2, was not significantly different from those in which glycerol was added to semen by Methods 3 and 4, but it was significantly higher than that found in semen in which the glycerol was added by Method 1 (54.4%). However, when averaged over the method of glycerolation, the post-thaw percentage of motile spermatozoa (range, 43.7-44.2%) and the percentage of intact acrosomes (range, 56.8-59.5%) did not differ significantly in semen subjected to gradual decrease in glycerol concentration and diluent osmolality (over 15 and 30 min) or by a one-step, 10-fold dilution. These data indicate that post-thaw survival of spermatozoa can be influenced by the way in which glycerol is added prior to freezing. However, post-thaw spermatozoa motility and acrosomal integrity can be maintained even

  19. 29 CFR 1903.9 - Trade secrets.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 5 2013-07-01 2013-07-01 false Trade secrets. 1903.9 Section 1903.9 Labor Regulations... INSPECTIONS, CITATIONS AND PROPOSED PENALTIES § 1903.9 Trade secrets. (a) Section 15 of the Act provides: “All... inspection or proceeding under this Act which contains or which might reveal a trade secret referred to...

  20. 29 CFR 401.11 - Secret ballot.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 2 2014-07-01 2014-07-01 false Secret ballot. 401.11 Section 401.11 Labor Regulations Relating to Labor OFFICE OF LABOR-MANAGEMENT STANDARDS, DEPARTMENT OF LABOR LABOR-MANAGEMENT STANDARDS MEANING OF TERMS USED IN THIS SUBCHAPTER § 401.11 Secret ballot. Secret ballot means the expression...

  1. 29 CFR 401.11 - Secret ballot.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 2 2010-07-01 2010-07-01 false Secret ballot. 401.11 Section 401.11 Labor Regulations Relating to Labor OFFICE OF LABOR-MANAGEMENT STANDARDS, DEPARTMENT OF LABOR LABOR-MANAGEMENT STANDARDS MEANING OF TERMS USED IN THIS SUBCHAPTER § 401.11 Secret ballot. Secret ballot means the expression...

  2. 29 CFR 401.11 - Secret ballot.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 2 2011-07-01 2011-07-01 false Secret ballot. 401.11 Section 401.11 Labor Regulations Relating to Labor OFFICE OF LABOR-MANAGEMENT STANDARDS, DEPARTMENT OF LABOR LABOR-MANAGEMENT STANDARDS MEANING OF TERMS USED IN THIS SUBCHAPTER § 401.11 Secret ballot. Secret ballot means the expression...

  3. 5 CFR 2421.15 - Secret ballot.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Secret ballot. 2421.15 Section 2421.15... FEDERAL LABOR RELATIONS AUTHORITY MEANING OF TERMS AS USED IN THIS SUBCHAPTER § 2421.15 Secret ballot. Secret ballot means the expression by ballot, voting machine or otherwise, but in no event by proxy, of...

  4. 22 CFR 1421.15 - Secret ballot.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 22 Foreign Relations 2 2013-04-01 2009-04-01 true Secret ballot. 1421.15 Section 1421.15 Foreign Relations FOREIGN SERVICE LABOR RELATIONS BOARD; FEDERAL LABOR RELATIONS AUTHORITY; GENERAL COUNSEL OF THE... THIS SUBCHAPTER § 1421.15 Secret ballot. Secret ballot means the expression by ballot, voting...

  5. 29 CFR 401.11 - Secret ballot.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 2 2012-07-01 2012-07-01 false Secret ballot. 401.11 Section 401.11 Labor Regulations Relating to Labor OFFICE OF LABOR-MANAGEMENT STANDARDS, DEPARTMENT OF LABOR LABOR-MANAGEMENT STANDARDS MEANING OF TERMS USED IN THIS SUBCHAPTER § 401.11 Secret ballot. Secret ballot means the expression...

  6. 5 CFR 2421.15 - Secret ballot.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 3 2011-01-01 2011-01-01 false Secret ballot. 2421.15 Section 2421.15... FEDERAL LABOR RELATIONS AUTHORITY MEANING OF TERMS AS USED IN THIS SUBCHAPTER § 2421.15 Secret ballot. Secret ballot means the expression by ballot, voting machine or otherwise, but in no event by proxy, of...

  7. 22 CFR 1421.15 - Secret ballot.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 22 Foreign Relations 2 2012-04-01 2009-04-01 true Secret ballot. 1421.15 Section 1421.15 Foreign Relations FOREIGN SERVICE LABOR RELATIONS BOARD; FEDERAL LABOR RELATIONS AUTHORITY; GENERAL COUNSEL OF THE... THIS SUBCHAPTER § 1421.15 Secret ballot. Secret ballot means the expression by ballot, voting...

  8. 29 CFR 452.97 - Secret ballot.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 2 2014-07-01 2014-07-01 false Secret ballot. 452.97 Section 452.97 Labor Regulations... OF 1959 Election Procedures; Rights of Members § 452.97 Secret ballot. (a) A prime requisite of elections regulated by title IV is that they be held by secret ballot among the members or in...

  9. 29 CFR 401.11 - Secret ballot.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 2 2013-07-01 2013-07-01 false Secret ballot. 401.11 Section 401.11 Labor Regulations Relating to Labor OFFICE OF LABOR-MANAGEMENT STANDARDS, DEPARTMENT OF LABOR LABOR-MANAGEMENT STANDARDS MEANING OF TERMS USED IN THIS SUBCHAPTER § 401.11 Secret ballot. Secret ballot means the expression...

  10. 29 CFR 452.97 - Secret ballot.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 2 2011-07-01 2011-07-01 false Secret ballot. 452.97 Section 452.97 Labor Regulations... OF 1959 Election Procedures; Rights of Members § 452.97 Secret ballot. (a) A prime requisite of elections regulated by title IV is that they be held by secret ballot among the members or in...

  11. 5 CFR 2421.15 - Secret ballot.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 5 Administrative Personnel 3 2014-01-01 2014-01-01 false Secret ballot. 2421.15 Section 2421.15... FEDERAL LABOR RELATIONS AUTHORITY MEANING OF TERMS AS USED IN THIS SUBCHAPTER § 2421.15 Secret ballot. Secret ballot means the expression by ballot, voting machine or otherwise, but in no event by proxy, of...

  12. 29 CFR 452.97 - Secret ballot.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 2 2012-07-01 2012-07-01 false Secret ballot. 452.97 Section 452.97 Labor Regulations... OF 1959 Election Procedures; Rights of Members § 452.97 Secret ballot. (a) A prime requisite of elections regulated by title IV is that they be held by secret ballot among the members or in...

  13. 29 CFR 1903.9 - Trade secrets.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 5 2012-07-01 2012-07-01 false Trade secrets. 1903.9 Section 1903.9 Labor Regulations... INSPECTIONS, CITATIONS AND PROPOSED PENALTIES § 1903.9 Trade secrets. (a) Section 15 of the Act provides: “All... inspection or proceeding under this Act which contains or which might reveal a trade secret referred to...

  14. 22 CFR 1421.15 - Secret ballot.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 2 2010-04-01 2010-04-01 true Secret ballot. 1421.15 Section 1421.15 Foreign Relations FOREIGN SERVICE LABOR RELATIONS BOARD; FEDERAL LABOR RELATIONS AUTHORITY; GENERAL COUNSEL OF THE... THIS SUBCHAPTER § 1421.15 Secret ballot. Secret ballot means the expression by ballot, voting...

  15. Quantum secret sharing with qudit graph states

    SciTech Connect

    Keet, Adrian; Fortescue, Ben; Sanders, Barry C.; Markham, Damian

    2010-12-15

    We present a unified formalism for threshold quantum secret sharing using graph states of systems with prime dimension. We construct protocols for three varieties of secret sharing: with classical and quantum secrets shared between parties over both classical and quantum channels.

  16. 5 CFR 2421.15 - Secret ballot.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 5 Administrative Personnel 3 2013-01-01 2013-01-01 false Secret ballot. 2421.15 Section 2421.15... FEDERAL LABOR RELATIONS AUTHORITY MEANING OF TERMS AS USED IN THIS SUBCHAPTER § 2421.15 Secret ballot. Secret ballot means the expression by ballot, voting machine or otherwise, but in no event by proxy, of...

  17. 29 CFR 1903.9 - Trade secrets.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 5 2011-07-01 2011-07-01 false Trade secrets. 1903.9 Section 1903.9 Labor Regulations... INSPECTIONS, CITATIONS AND PROPOSED PENALTIES § 1903.9 Trade secrets. (a) Section 15 of the Act provides: “All... inspection or proceeding under this Act which contains or which might reveal a trade secret referred to...

  18. 29 CFR 1202.4 - Secret ballot.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 4 2010-07-01 2010-07-01 false Secret ballot. 1202.4 Section 1202.4 Labor Regulations Relating to Labor (Continued) NATIONAL MEDIATION BOARD RULES OF PROCEDURE § 1202.4 Secret ballot. In conducting such investigation, the Board is authorized to take a secret ballot of the employees involved,...

  19. 29 CFR 1202.4 - Secret ballot.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 4 2012-07-01 2012-07-01 false Secret ballot. 1202.4 Section 1202.4 Labor Regulations Relating to Labor (Continued) NATIONAL MEDIATION BOARD RULES OF PROCEDURE § 1202.4 Secret ballot. In conducting such investigation, the Board is authorized to take a secret ballot of the employees involved,...

  20. 29 CFR 1202.4 - Secret ballot.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 4 2014-07-01 2014-07-01 false Secret ballot. 1202.4 Section 1202.4 Labor Regulations Relating to Labor (Continued) NATIONAL MEDIATION BOARD RULES OF PROCEDURE § 1202.4 Secret ballot. In conducting such investigation, the Board is authorized to take a secret ballot of the employees involved,...

  1. 22 CFR 1421.15 - Secret ballot.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 2 2011-04-01 2009-04-01 true Secret ballot. 1421.15 Section 1421.15 Foreign Relations FOREIGN SERVICE LABOR RELATIONS BOARD; FEDERAL LABOR RELATIONS AUTHORITY; GENERAL COUNSEL OF THE... THIS SUBCHAPTER § 1421.15 Secret ballot. Secret ballot means the expression by ballot, voting...

  2. 29 CFR 1202.4 - Secret ballot.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 4 2013-07-01 2013-07-01 false Secret ballot. 1202.4 Section 1202.4 Labor Regulations Relating to Labor (Continued) NATIONAL MEDIATION BOARD RULES OF PROCEDURE § 1202.4 Secret ballot. In conducting such investigation, the Board is authorized to take a secret ballot of the employees involved,...

  3. 5 CFR 2421.15 - Secret ballot.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 5 Administrative Personnel 3 2012-01-01 2012-01-01 false Secret ballot. 2421.15 Section 2421.15... FEDERAL LABOR RELATIONS AUTHORITY MEANING OF TERMS AS USED IN THIS SUBCHAPTER § 2421.15 Secret ballot. Secret ballot means the expression by ballot, voting machine or otherwise, but in no event by proxy, of...

  4. 29 CFR 452.97 - Secret ballot.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 2 2010-07-01 2010-07-01 false Secret ballot. 452.97 Section 452.97 Labor Regulations... OF 1959 Election Procedures; Rights of Members § 452.97 Secret ballot. (a) A prime requisite of elections regulated by title IV is that they be held by secret ballot among the members or in...

  5. 29 CFR 452.97 - Secret ballot.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 2 2013-07-01 2013-07-01 false Secret ballot. 452.97 Section 452.97 Labor Regulations... OF 1959 Election Procedures; Rights of Members § 452.97 Secret ballot. (a) A prime requisite of elections regulated by title IV is that they be held by secret ballot among the members or in...

  6. 22 CFR 1421.15 - Secret ballot.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 22 Foreign Relations 2 2014-04-01 2014-04-01 false Secret ballot. 1421.15 Section 1421.15 Foreign Relations FOREIGN SERVICE LABOR RELATIONS BOARD; FEDERAL LABOR RELATIONS AUTHORITY; GENERAL COUNSEL OF THE... THIS SUBCHAPTER § 1421.15 Secret ballot. Secret ballot means the expression by ballot, voting...

  7. 29 CFR 1202.4 - Secret ballot.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 4 2011-07-01 2011-07-01 false Secret ballot. 1202.4 Section 1202.4 Labor Regulations Relating to Labor (Continued) NATIONAL MEDIATION BOARD RULES OF PROCEDURE § 1202.4 Secret ballot. In conducting such investigation, the Board is authorized to take a secret ballot of the employees involved,...

  8. 29 CFR 1903.9 - Trade secrets.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 5 2010-07-01 2010-07-01 false Trade secrets. 1903.9 Section 1903.9 Labor Regulations... INSPECTIONS, CITATIONS AND PROPOSED PENALTIES § 1903.9 Trade secrets. (a) Section 15 of the Act provides: “All... inspection or proceeding under this Act which contains or which might reveal a trade secret referred to...

  9. 29 CFR 1903.9 - Trade secrets.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 5 2014-07-01 2014-07-01 false Trade secrets. 1903.9 Section 1903.9 Labor Regulations... INSPECTIONS, CITATIONS AND PROPOSED PENALTIES § 1903.9 Trade secrets. (a) Section 15 of the Act provides: “All... inspection or proceeding under this Act which contains or which might reveal a trade secret referred to...

  10. Biomass and lipid production of heterotrophic microalgae Chlorella protothecoides by using biodiesel-derived crude glycerol.

    PubMed

    Chen, Yen-Hui; Walker, Terry H

    2011-10-01

    Microalgal lipids may be a more sustainable biodiesel feedstock than crop oils. We have investigated the potential for using the crude glycerol as a carbon substrate. In batch mode, the biomass and lipid concentration of Chlorella protothecoides cultivated in a crude glycerol medium were, respectively, 23.5 and 14.6 g/l in a 6-day cultivation. In the fed-batch mode, the biomass and lipid concentration improved to 45.2 and 24.6 g/l after 8.2 days of cultivation, respectively. The maximum lipid productivity of 3 g/l day in the fed-batch mode was higher than that produced by batch cultivation. This work demonstrates the feasibility of crude biodiesel glycerol as an alternative carbon substrate to glucose for microalgal cultivation and a cost reduction of carbon substrate feed in microalgal lipid production may be expected. PMID:21691839

  11. Efficient production of ethanol from crude glycerol by a Klebsiella pneumoniae mutant strain.

    PubMed

    Oh, Baek-Rock; Seo, Jeong-Woo; Heo, Sun-Yeon; Hong, Won-Kyung; Luo, Lian Hua; Joe, Min-ho; Park, Don-Hee; Kim, Chul Ho

    2011-02-01

    A mutant strain of Klebsiella pneumoniae, termed GEM167, was obtained by γ irradiation, in which glycerol metabolism was dramatically affected on exposure to γ rays. Levels of metabolites of the glycerol reductive pathway, 1,3-propanediol (1,3-PD) and 3-hydroxypropionic acid (3-HP), were decreased in the GEM167 strain compared to a control strain, whereas the levels of metabolites derived from the oxidative pathway, 2,3-butanediol (2,3-BD), ethanol, lactate, and succinate, were increased. Notably, ethanol production from glycerol was greatly enhanced upon fermentation by the mutant strain, to a maximum production level of 21.5 g/l, with a productivity of 0.93 g/l/h. Ethanol production level was further improved to 25.0 g/l upon overexpression of Zymomonas mobilis pdc and adhII genes encoding pyruvate decarboxylase (Pdc) and aldehyde dehydrogenase (Adh), respectively in the mutant strain GEM167. PMID:21186120

  12. Impact of glycerol-3-phosphate dehydrogenase on virulence factor production by Pseudomonas aeruginosa.

    PubMed

    Daniels, Jonathan B; Scoffield, Jessica; Woolnough, Jessica L; Silo-Suh, Laura

    2014-12-01

    Pseudomonas aeruginosa establishes life-long chronic infections in the cystic fibrosis (CF) lung by utilizing various adaptation strategies. Some of these strategies include altering metabolic pathways to utilize readily available nutrients present in the host environment. The airway sputum contains various host-derived nutrients that can be utilized by P. aeruginosa, including phosphatidylcholine, a major component of lung surfactant. Pseudomonas aeruginosa can degrade phosphatidylcholine to glycerol and fatty acids to increase the availability of usable carbon sources in the CF lung. In this study, we show that some CF-adapted P. aeruginosa isolates utilize glycerol more efficiently as a carbon source than nonadapted isolates. Furthermore, a mutation in a gene required for glycerol utilization impacts the production of several virulence factors in both acute and chronic isolates of P. aeruginosa. Taken together, the results suggest that interference with this metabolic pathway may have potential therapeutic benefits. PMID:25409940

  13. An isocratic HPLC method for the determination of sorbitol and glycerol in pharmaceutical formulations.

    PubMed

    Simonzadeh, Ninus; Ronsen, Bruce

    2012-08-01

    Sorbitol and glycerol, along with other inactive ingredients such as preservatives and dyes, are commonly used in various pharmaceutical and personal care products. To accurately assess the effectiveness of various formulations containing sorbitol and/or glycerol, their quantitative determination is essential. In the current study, two types of detectors (a Varian evaporative light scattering detector and an Agilent ultraviolet-visible detector) are evaluated for the assay of working sample solutions. The two detection techniques are complimentary, and a comparison of the results obtained using the two detectors is presented here. The current method is shown to be stability-indicating and free from interference from any of the formulation excipients and potential degradation products. The method is reproducible, accurate, sensitive and selective. It provides enhanced detection sensitivity for sorbitol and comparable sensitivity for glycerol versus similar methods reported in the literature that utilize a refractive index detector for the analysis of either of the two polyols. PMID:22565491

  14. Esterification of glycerol 3-phosphate in lactating guinea-pig mammary gland

    PubMed Central

    Kuhn, N. J.

    1967-01-01

    1. The presence of palmitoyl-CoA–l-glycerol 3-phosphate palmitoyltransferase (EC 2.3.1.15) has been demonstrated in a particulate fraction of mammary tissue from lactating guinea pigs. 2. Cell-free preparations also catalysed the activation of palmitate and oleate, and the conversion of enzymically formed phosphatidic acid into glycerides, in accord with the Kennedy pathway of glyceride formation. 3. The properties of the system that esterifies l-glycerol 3-phosphate were studied with respect to substrates and cofactors, and the reaction product was shown to be phosphatidic acid (1,2-diacyl glycerol 3-phosphate). 4. The extent to which newly formed phosphatidic acid was converted into glyceride in a cell-free system was dependent on the nature of the acyl donor, the concentration of subcellular particles, the time of incubation and the concentration of Mg2+. PMID:6070127

  15. Stimulation of incretin secreting cells.

    PubMed

    Pais, Ramona; Gribble, Fiona M; Reimann, Frank

    2016-02-01

    The incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon like peptide-1 (GLP-1) are secreted from enteroendocrine cells in the gut and regulate physiological and homeostatic functions related to glucose control, metabolism and food intake. This review provides a systematic summary of the molecular mechanisms underlying secretion from incretin cells, and an understanding of how they sense and interact with lumen and vascular factors and the enteric nervous system through transporters and G-protein coupled receptors (GPCRs) present on their surface to ultimately culminate in hormone release. Some of the molecules described below such as sodium coupled glucose transporter 1 (SGLT1), G-protein coupled receptor (GPR) 119 and GPR40 are targets of novel therapeutics designed to enhance endogenous gut hormone release. Synthetic ligands at these receptors aimed at treating obesity and type 2 diabetes are currently under investigation. PMID:26885360

  16. Stimulation of incretin secreting cells

    PubMed Central

    Pais, Ramona; Gribble, Fiona M.; Reimann, Frank

    2016-01-01

    The incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon like peptide-1 (GLP-1) are secreted from enteroendocrine cells in the gut and regulate physiological and homeostatic functions related to glucose control, metabolism and food intake. This review provides a systematic summary of the molecular mechanisms underlying secretion from incretin cells, and an understanding of how they sense and interact with lumen and vascular factors and the enteric nervous system through transporters and G-protein coupled receptors (GPCRs) present on their surface to ultimately culminate in hormone release. Some of the molecules described below such as sodium coupled glucose transporter 1 (SGLT1), G-protein coupled receptor (GPR) 119 and GPR40 are targets of novel therapeutics designed to enhance endogenous gut hormone release. Synthetic ligands at these receptors aimed at treating obesity and type 2 diabetes are currently under investigation. PMID:26885360

  17. Effect of glycerol on mechanical and physical properties of silver-chitosan nanocomposite films

    NASA Astrophysics Data System (ADS)

    Susilowati, E.; Kartini, I.; Santosa, S. J.; Triyono

    2016-02-01

    The effect of using glycerol as plasticizer on mechanical and physical properties of silver-chitosan nanocomposite films have been studied. The nanocomposite films were prepared via three steps consisting of silver-chitosan colloidal nanocomposites preparation, adding of glycerol to colloids and silver-chitosan nanocomposites films formation. During the first step, silver ions were reduced by glucose and accelerated by sodium hydroxide (NaOH). Chitosan of 1% (v/v) act as stabilizing agent. Glycerol with volume variation of 0.2, 0.4, 0.6, 8 and 1.0 mL was added colloidal nanocomposites of 60 mL on the second step. On the third step, colloidal nanocomposites were cast on the polypropylene plate and dried at room temperature. The as-prepared films were then neutralized by NaOH and rinsed with distilled water until the filtrate reached the pH of 7. The colloidal nanocomposites were characterized by UV-Vis spectroscopy and transmission electron microscopy (TEM). The film were characterized by X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The mechanical properties, swelling capacity, water vapor permeability (WVP) of the films were also studied. The results indicated that the addition of different amounts of glycerol on colloidal nanocomposites effects on mechanical and physical properties of the resulted nanocomposite films. The elongation and tensile strength were gradually increased as the glycerol amount. Meanwhile, the swelling capacity, WVP, and crystallinity of the film also showed enhancement at increasing glycerol amount. However, the thermal stability decreased.

  18. Improved 1,3-Propanediol Synthesis from Glycerol by the Robust Lactobacillus reuteri Strain DSM 20016.

    PubMed

    Ricci, Maria Antonietta; Russo, Annamaria; Pisano, Isabella; Palmieri, Luigi; de Angelis, Maria; Agrimi, Gennaro

    2015-06-01

    Various Lactobacillus reuteri strains were screened for the ability to convert glycerol to 1,3- propanediol (1,3-PDO) in a glycerol-glucose co-fermentation. Only L. reuteri DSM 20016, a well-known probiotic, was able to efficiently carry out this bioconversion. Several process strategies were employed to improve this process. CO(2+) addition to the fermentation medium, led to a high product titer (46 g/l) of 1,3-PDO and to improved biomass synthesis. L. reuteri DSM 20016 produced also ca. 3 μg/g of cell dry weight of vitamin B12, conferring an economic value to the biomass produced in the process. Incidentally, we found that L. reuteri displays the highest resistance to CO(2+) ions ever reported for a microorganism. Two waste materials (crude glycerol from biodiesel industry and spruce hydrolysate from paper industry) alone or in combination were used as feedstocks for the production of 1,3-PDO by L. reuteri DSM 20016. Crude glycerol was efficiently converted into 1,3-PDO although with a lower titer than pure glycerol (-18%). Compared with the fermentation carried out with pure substrates, the 1,3- PDO produced was significantly lower (40.7 vs. 24.2 g/l) using cellulosic hydrolysate and crude glycerol, but strong increases of the maximal biomass produced (+27%) and of the glucose consumption rate (+46%) were found. The results of this study lay the foundation for further investigations to exploit the biotechnological potential of L. reuteri DSM 20016 to produce 1,3-PDO and vitamin B12 using industry byproducts. PMID:25588555

  19. Evidence for a glycerol pathway through aquaporin 1 (CHIP28) channels.

    PubMed

    Abrami, L; Tacnet, F; Ripoche, P

    1995-07-01

    Permeabilities to glycerol and small non-electrolytes of three Aquaporin 1 CHIP (AQP1) water channels were measured in AQP1 cRNA-injected Xenopus laevis oocytes and in human AQP1 channels reconstituted in proteoliposomes. By an "osmotic" swelling assay, significant increases of ethylene glycol, glycerol and 1,3-propanediol apparent permeability coefficients (P'solutes) were found in oocytes expressing human, rat and frog AQP1. p-Chloromercuribenzene sulphonate (pCMBS) and CuSO4 inhibited, by 95% and 58% respectively, apparent glycerol permeability (P'gly) in oocytes expressing human AQP1. pCMBS inhibition was reversed by beta-mercaptoethanol and CuSO4 inhibition was partly reversed by the Cu(2+)-binding peptide Gly-Gly-His. Tritiated glycerol uptakes confirmed the augmented P'gly value of AQP1 cRNA-injected oocytes. In contrast, no increases of urea, meso-erythritol, D-or L-threitol, xylitol and mannitol uptakes were detected. Stopped-flow light scattering experiments performed with human AQP1 proteoliposomes also revealed a much greater increase of P'gly than did those with protein-free liposomes; the initial rate of proteoliposomes also swelling was inhibited by 96.2% with HgCl2 and by 72.5% with CuSO4. In AQP1 cRNA-injected oocytes and in proteoliposomes, the value of the glycerol reflection coefficient was 0.74-0.80, indicating that water and glycerol share the same pathway. All these results provide strong evidence that water and certain small solutes permeate the AQP1 channels expressed at the surface of X. laevis oocytes or reconstituted in proteoliposomes. The urea exclusion suggests that the selectivity of the AQP1 channels not only depends on the size of the solutes but probably also on their flexibility and their ability to form H-bonds. PMID:7491270

  20. Ultraviolet stimulated melanogenesis by human melanocytes is augmented by di-acyl glycerol but not TPA

    SciTech Connect

    Friedmann, P.S.; Wren, F.E.; Matthews, J.N. )

    1990-02-01

    Epidermal melanocytes (MC) synthesize melanin in response to ultraviolet radiation (UVR). The mechanisms mediating the UV-induced activation of melanogenesis are unknown but since UVR induces turnover of membrane phospholipids generating prostaglandins (PGs) and other products, it is possible that one of these might provide the activating signal. We have examined the effects of prostaglandins (PGs) E1, E2, D2, F2 alpha, and di-acyl glycerol upon the UV-induced responses of cultured human MC and the Cloudman S91 melanoma cell line. The PGs had little effect on unirradiated cells and did not alter the response to UVR in either human MC or S91 melanoma cells. However, a synthetic analogue of di-acyl glycerol, 1-oleyl 2-acetyl glycerol (OAG), caused a significant (P less than 0.0001), dose-related augmentation of melanin content both in human MC (seven-fold) and S91 cells (three-fold). UVR caused a significant augmentation of the OAG-induced melanogenesis of both human MC and S91 cells. Since OAG is known to activate protein kinase C, it was possible that the observed modulation of the UVR signal could be via that pathway. Di-octanoyl glycerol, another di-acyl glycerol, which activates kinase C, caused a small (70%) increase in melanogenesis in MC which was not altered by UVR. However, 12-0 tetradecanoyl phorbol 13-acetate (TPA), a potent activator of protein kinase C, had no significant effect on either basal or UV-induced melanin synthesis in either cell type. These data suggest that the UV-induced signal activating melanogenesis could be mediated by di-acyl glycerol. Furthermore, they imply that the signal is transduced via an alternative, pathway that might be independent of protein kinase C.