Sample records for acrosome reaction mediated

  1. Delineation of downstream signalling components during acrosome reaction mediated by heat solubilized human zona pellucida

    Talwar Pankaj


    Full Text Available Abstract Background Human egg is enveloped by a glycoproteinaceous matrix, zona pellucida (ZP, responsible for binding of the human spermatozoa to the egg and induction of acrosomal exocytosis in the spermatozoon bound to ZP. In the present manuscript, attempts have been made to delineate the downstream signalling components employed by human ZP to induce acrosome reaction. Methods Heat-solubilized human ZP (SIZP was used to study the induction of acrosome reaction in capacitated human spermatozoa using tetramethylrhodamine isothiocyanate conjugated Pisum sativum agglutinin (TRITC-PSA in absence or presence of various pharmacological inhibitors. In addition, intracellular calcium ([Ca2+]i levels in sperm using Fluo-3 acetoxymethyl ester as fluorescent probe were also estimated in response to SIZP. Results SIZP induces acrosomal exocytosis in capacitated human sperm in a dose dependent manner accompanied by an increase in [Ca2+]i. Human SIZP mediated induction of acrosome reaction depends on extracellular Ca2+ and involves activation of Gi protein-coupled receptor, tyrosine kinase, protein kinases A & C and phosphoinositide 3 (PI3- kinase. In addition, T-type voltage operated calcium channels and GABA-A receptor associated chloride (Cl- channels play an important role in SIZP mediated induction of acrosome reaction. Conclusions Results described in the present study provide a comprehensive account of the various downstream signalling components associated with human ZP mediated acrosome reaction.

  2. The human acrosome reaction

    H.W.G.Baker; D.Y.Liu; C.Garrett; M.Martic


    We developed tests of sperm-oocyte interaction: sperm-zona binding, zona-induced acrosome reaction, spermzona penetration and sperm-oolemma binding, using oocytes which failed to fertilise in clinical in vitro fertilization (IVF). Although oocyte defects contribute to failure of sperm oocyte interaction, rarely are all oocytes from one woman affected. Low or zero fertilization in standard IVFwas usually caused by sperm abnormalities. Poor sperm-zona pellucida binding was frequently associated with failure of standard IVF and obvious defects of sperm motility or morphology. The size and shape of the acrosome is particularly important for sperm binding to the oocyte. The proportion of acrosome intact sperm in the insemination medium was related to the IVF rate. Inducing the acrosome reaction with a calcium ionophore reduced sperm-zona binding. Blocking acrosome dispersal with an acrosin inhibitor prevented spermzona penetration. Sperm-zona penetration was even more highly related to IVF rates than was sperm-zona binding. Some patients had low or zero fertilization rates with standard IVF but normal sperm by conventional tests and normal sperm-zona binding. Few of their sperm underwent the acrosome reaction on the surface of the zona and none penetrated the zona. In contrast, fertilization and pregnancy rates were high with intracytoplasmic sperm injection. We call thiscondition defective zona pellucida induced acrosome reaction. Discovery of the nature of the abnormalities in the signal transduction and effector pathways of the human zona pellucida induced acrosome reaction should result in simpler tests and treatments for the patients and also provide new leads for contraceptive development.

  3. Carbohydrates mediate sperm-ovum adhesion and triggering of the acrosome reaction



    The fertilization process is the net result of a complex sequence of events that collectively result in the fusion of the opposite gametes. The male gamete undergoes continuous morphological and biochemical modifications during sperm development in the testis (spermatogenesis), maturation in the epididymis, and capacitation in the female reproductive tract. Only the capacitated spermatozoa are able to recognize and bind to the bioactive glycan residue(s) on the ovum's extracellular coat, the zona pellucida (ZP). Sperm-zona binding in the mouse and several other species is believed to take place in two stages. First, capacitated (acrosome-intact) spermatozoa loosely and reversibly adhere to the zona-intact ovum. In the second stage tight irreversible binding occurs. Both types of bindings are attributed to the presence of glycan- binding proteins (receptors) on the sperm plasma membrane and their complementary bioactive glycan units (ligands) on the surface of the ZP. The carbohydrate-mediated adhesion event initiates a signal transduction cascade resulting in the exocytosis of acrosomal contents. This step is believed to be prerequisite which allows the hypemctivated acrosome-reacted spermatozoa to penetrate the ZP and fertilize the ovum. This review focuses on the role of carbohydrate residues in sperm-ovum interaction, and triggering of the acrosome reaction. I have attempted to discuss extensive progress that has been made to enhance our understanding of the well programmed multiple molecular events necessary for successful fertilization. This review will identify these events, and discuss the functional significance of carbohydrates in these events.

  4. Zn2+-stimulation of sperm capacitation and of the acrosome reaction is mediated by EGFR activation.

    Michailov, Yulia; Ickowicz, Debbi; Breitbart, Haim


    Extracellular zinc regulates cell proliferation via the MAP1 kinase pathway in several cell types, and has been shown to act as a signaling molecule. The testis contains a relatively high concentration of Zn(2+), required in both the early and late stages of spermatogenesis. Despite the clinical significance of this ion, its role in mature sperm cells is poorly understood. In this study, we characterized the role of Zn(2+) in sperm capacitation and in the acrosome reaction. Western blot analysis revealed the presence of ZnR of the GPR39 type in sperm cells. We previously demonstrated the presence of active epidermal growth factor receptor (EGFR) in sperm, its possible transactivation by direct activation of G-protein coupled receptor (GPCR), and its involvement in sperm capacitation and in the acrosome reaction (AR). We show here that Zn(2+) activates the EGFR during sperm capacitation, which is mediated by activation of trans-membrane adenylyl cyclase (tmAC), protein kinase A (PKA), and the tyrosine kinase, Src. Moreover, the addition of Zn(2+) to capacitated sperm caused further stimulation of EGFR and phosphatydil-inositol-3-kinase (PI3K) phosphorylation, leading to the AR. The stimulation of the AR by Zn(2+) also occurred in the absence of Ca(2+) in the incubation medium, and required the tmAC, indicating that Zn(2+) activates a GPCR. The AR stimulated by Zn(2+) is mediated by GPR39 receptor, PKA, Src and the EGFR, as well as the EGFR down-stream effectors PI3K, phospholipase C (PLC) and protein kinase C (PKC). These data support a role for extracellular zinc, acting through the ZnR, in regulating multiple signaling pathways in sperm capacitation and the acrosome reaction.

  5. The laminin-induced acrosome reaction in human sperm is mediated by Src kinases and the proteasome.

    Tapia, Silvia; Rojas, Marcelo; Morales, Patricio; Ramirez, Marco A; Diaz, Emilce S


    The aim of this work was to determine whether laminin (Ln), an extracellular matrix protein, induces the intracellular events that may be involved in producing the acrosome reaction in human sperm. To this end, we evaluated the effect of Ln on tyrosine phosphorylation, intracellular calcium concentration, proteasome activity, and phosphorylation in human sperm. Aliquots of highly motile sperm selected with a Percoll gradient, were incubated with different concentrations of Ln (0-20 μg/ml) for different periods (0-18 h). The percentage of viable acrosome-reacted sperm was evaluated using fluorescein isothiocyanate-labeled Pisum sativum agglutinin and Hoechst 33258 DNA dye. Tyrosine phosphorylation was evaluated by Western blot analysis. The chymotrypsin-like activity of the proteasome was evaluated with a fluorogenic peptide, and intracellular calcium concentration was measured with fura-2. The results indicate that Ln stimulated the acrosome reaction of human sperm in a dose-dependent manner. This increase was drastically inhibited in the presence of herbimycin A, SU6656, and epoxomicin. In addition, Ln increased proteasome activity and phosphorylation; both events were inhibited by herbimycin A and SU6656. Finally, Ln induced an increase in intracellular calcium concentration, which was inhibited by SU6656 and epoxomicin. These results suggest that Ln is able to induce the acrosome reaction. This effect may be mediated by Src kinase and the proteasome, with the consequent induction of a calcium influx.

  6. Acrosome reaction: relevance of zona pellucida glycoproteins

    Satish K Gupta; Beena Bhandari


    During mammalian fertilisation,the zona pellucida(ZP)matrix surrounding the oocyte is responsible for the binding of the spermatozoa to the oocyte and induction of the acrosome reaction(AR)in the ZP-bound spermatozoon.The AR is crucial for the penetration of the ZP matrix by spermatozoa.The ZP matrix in mice is composed of three glycoproteins designated ZP1,ZP2 and ZP3,whereas in humans,it is composed of four(ZP1,ZP2,ZP3 and ZP4).ZP3 acts as the putative primary sperm receptor and is responsible for AR induction in mice,whereas in humans(in addition to ZP3),ZP1 and ZP4 also induce the AR.The ability of ZP3 to induce the AR resides in its C-terminal fragment.O-linked glycans are critical for the murine ZP3-mediated AR.However,N-linked glycans of human ZP1,ZP3 and ZP4 have important roles in the induction of the AR.Studies with pharmacological inhibitors showed that the ZP3-induced AR involves the activation of the G1-coupled receptor pathway,whereas ZP1-and ZP4-mediated ARs are independent of this pathway.The ZP3-induced AR involves the activation of T-type voltage-operated calcium channels(VOCCs),whereas ZP1-and ZP4-induced ARs involve both T-and L-type VOCCs.To conclude,in mice,ZP3 is primarily responsible for the binding of capacitated spermatozoa to the ZP matrix and induction of the AR,whereas in humans(in addition to ZP3),ZP1 and ZP4 also participate in these stages of fertilisation.

  7. Equatorin is not essential for acrosome biogenesis but is required for the acrosome reaction

    Hao, Jianxiu [State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Chen, Min [State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101 (China); Ji, Shaoyang; Wang, Xiaona; Wang, Yanbo [State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Huang, Xingxu [MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center of Nanjing University, Nanjing Biomedical Research Institute, National Resource Center for Mutant Mice, Nanjing 210061 (China); Yang, Lin; Wang, Yaqing [State Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101 (China); Cui, Xiuhong; Lv, Limin [State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101 (China); Liu, Yixun, E-mail: [State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101 (China); Gao, Fei, E-mail: [State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101 (China)


    Highlights: • Eqtn knockout mice were used for these experiments. • In vivo and in vitro fertilization analyses were performed. • Eqtn-deficient sperm were evaluated by transmission electron microscopy (TEM) and an A23187-induced acrosome reaction (AR) assay. • Co-immunoprecipitation (Co-IP) was performed to assess the interaction between Eqtn and the SNARE complex. - Abstract: The acrosome is a specialized organelle that covers the anterior part of the sperm nucleus and plays an essential role in mammalian fertilization. However, the regulatory mechanisms controlling acrosome biogenesis and acrosome exocytosis during fertilization are largely unknown. Equatorin (Eqtn) is a membrane protein that is specifically localized to the acrosomal membrane. In the present study, the physiological functions of Eqtn were investigated using a gene knockout mouse model. We found that Eqtn{sup −/−} males were subfertile. Only approximately 50% of plugged females were pregnant after mating with Eqtn{sup −/−} males, whereas more than 90% of plugged females were pregnant after mating with control males. Sperm and acrosomes from Eqtn{sup −/−} mice presented normal motility and morphology. However, the fertilization and induced acrosome exocytosis rates of Eqtn-deficient sperm were dramatically reduced. Further studies revealed that the Eqtn protein might interact with Syntaxin1a and SNAP25, but loss of Eqtn did not affect the protein levels of these genes. Therefore, our study demonstrates that Eqtn is not essential for acrosome biogenesis but is required for the acrosome reaction. Eqtn is involved in the fusion of the outer acrosomal membrane and the sperm plasma membrane during the acrosome reaction, most likely via an interaction with the SNARE complex.

  8. Study on the Vesiculation during Mouse Sperm Acrosome Reaction

    林家豪; 周作民; 胡志刚; 王黎熔; 林敏; 张适


    The location of the mono-membrane and the bi-membrane vesicles of mouse sperm was identified using Con A in conjugation with the colloidal gold. The observation showed that both mono-membrane vesicfes and outer layer of the hi-membrane vesicles come from the outer acrosome membrane. The inner membrane layer of the bi-member vesicles and residual membrane distributed among the vesicles are really the ptasmatemma. It is suggested that the outer acrosome membrane did not fuse with the pfasmafemma during mouse sperm acrosome reaction and that both the mono-membrane and the bi-membrane vesicles of mouse sperm were formed due to winding of the outer acrosome membrane.

  9. Changes in the distribution and molecular mass of boar sperm acrosome-associated 1 proteins during the acrosome reaction; their validity as indicators for occurrence of the true acrosome reaction.

    Ogura, Yukari; Takagishi, Yuki; Harayama, Hiroshi


    The aims of this study were to investigate changes in the distribution and molecular mass of boar sperm acrosome-associated 1 (SPACA1) proteins during the acrosome reaction and to discuss validity of SPACA1 proteins as indicators for occurrence of the true acrosome reaction. Boar ejaculated spermatozoa were used for induction of the extracellular Ca(2+)-dependent acrosome reaction (true acrosome reaction) or acrosomal damages (false acrosome reaction) and then subjected to double staining with the anti-SPACA1 protein antibody and FITC-PNA and Western blotting. Extracellular Ca(2+)-dependently acrosome-reacted spermatozoa were characterized by appearance of SPACA1 proteins in the postacrosomal region (; these spermatozoa were classified into SP-3&AR pattern of double staining). However, SPACA1 proteins were not observed in the postacrosomal region of frozen-thawed spermatozoa with severely damaged acrosomes (; these spermatozoa were classified into SP-2&AR pattern). Moreover, the spermatozoa in which acrosomes were severely damaged by incubation with cyclodextrins and without CaCl2 were classified into either SP-2&AR or SP-3&AR pattern. Although SPACA1 proteins were detected mainly as 36-42kDa proteins in the spermatozoa with intact acrosomes, small types of SPACA1 proteins (15-28kDa) increased in extracellular Ca(2+)-dependently acrosome-reacted spermatozoa as well as frozen-thawed spermatozoa with damaged acrosomes. These results show the increase of boar spermatozoa classified into SP-3&AR pattern after incubation in the medium with CaCl2 and without cyclodextrins indicates occurrence of the true acrosome reaction. Moreover, we suggest the increase of small types of SPACA1 proteins is a valid indicator for occurrence of the acrosomal disintegration arising from the true and false acrosome reactions.

  10. Roles of tumor necrosis factor alpha on sperm acrosin activity and acrosome reaction

    Shu-LingBian; Guo-YiLiu; Hai-XiaWen; Shu-ZhenWang; JiangNi; WeiZhang; HuiSi


    Aim: To study the roles of tumor necrosis factor alpha (TNF-a)on the sperm acrosin activity and acrosome reaction. Methods:The sperm acrosin activity was tested by the method of BAEE/ADH Unity and the acrosome reaction by the Triple-stain technique. Results: TNF-a decreased the sperm acrosin activityand acrosome reaction (P<0.01, P<0.01, respectively);

  11. Effect of divalent ions in acrosome reaction induced by glycosamineglycans in porcine spermatozoa.

    Delgado, N M; Carranco, A; Merchant, H; Reyes, R


    Magnesium, calcium, and zinc at the concentration of 10 microM are capable of inducing a "true" acrosome reaction in the pig spermatozoa judged by the criteria of the fusion of the acrosome and the plasmatic membrane at the anterior region or the sperm nucleus. The optimal percent of acrosome reaction reached by any of the ions tested as a whole was 50%. When glycosamineglycan sulfate (GAGs) plus 10 microM of Mg++, Ca++, or Zn++ was added, they reach to 70-80% of acrosome reaction. At the electrom microscope, thin sections taken from pig spermatozoa treated with ions, GAGs, or ion + GAGs under optimal experimental conditions revealed the same pattern of acrosomal reaction. Results suggest the important role that divalent cations play in general in the induction of the acrosome reaction and question the so-called essential role of calcium ions.

  12. Trehalose enhances osmotic tolerance and suppresses lysophosphatidylcholine-induced acrosome reaction in ram spermatozoon.

    Ahmad, E; Naseer, Z; Aksoy, M; Küçük, N; Uçan, U; Serin, I; Ceylan, A


    This study was aimed to investigate the influence of trehalose on osmotic tolerance and the ability of ram spermatozoon to undergo acrosome reaction induced by lysophosphatidylcholine (LPC). In experiment 1, the diluted ejaculates were exposed to anisosmotic fructose solutions (70, 500, 750 and 1000 mOsm l(-1) ) with or without 50 mm trehalose. The presence of trehalose in hyperosmotic conditions enhanced (P ram spermatozoon and suppresses their ability to undergo LPC and cryo-induced acrosome reaction.

  13. Effects of No on spontaneous acrosome reaction in AsAb positive rat spermatozoa

    ZhanW; NiJ


    Objective:To explore the effect of NO on the spontaneous acrosome reaction in antisperm antibody (AsAb) positive rat spermatozoa.Methods:The rat model of AsAb was set up by artificial immunization.The level of AsAb in blood serum was determined by TAT and ELISA.Rat spermatozoa was visualized by staining the acrosome with Coomassie brilliant blue.The NO concentration in rat spermatozoa was assayed by HPLC.Results:The percentage of acrosome reaction,NO concentration,superoxide dismutase(SOD) and Na+-K+ ATPase activity in AsAb positive rat spermatozoa were significantly decreased compared with the control group.Low dose of NO(SNP 10-9-10-8mol/L) increased the percentage of acrosome reaction and SOD activity,but had no effect on Na+-K+ATPase activity.High dose of NO(SNP 10-6-10-4mol/L) decreased the three items.Conclusion:The decrease in acrosome reaction in positive AsAb rat spermatozoa might be related to a decrease in NO and increase in O2-.(the SOD activity was decreased)in sperm.A low dose of NO might increase the percentage of acrosome reaction in AsAb positive rat by inhibiting the superoxide,while a high dose of NO was harmful to sperm function.

  14. Evidence for the involvement of metalloendoproteases in the acrosome reaction in sea urchin sperm.

    Farach, H A; Mundy, D I; Strittmatter, W J; Lennarz, W J


    An essential initial step in fertilization in the sea urchin Strongylocentrotus purpuratus is an intracellular membrane fusion event in the sperm known as the acrosome reaction. This Ca2+-dependent, exocytotic process involves fusion of the membrane of the acrosomal vesicle and the plasma membrane. Recently, metalloendoproteases requiring divalent metals have been implicated in several Ca2+-dependent membrane fusion events in other biological systems. In view of the suggested involvement of Zn2+ in the sea urchin sperm acrosome reaction (Clapper, D.L., Davis, J.A., Lamothe, P.J., Patton, C., and Epel, D. (1985) J. Cell Biol. 100, 1817-1824) and the fact that Zn2+ is a metal cofactor for metalloendoproteases, we investigated the potential role of this protease in the acrosome reaction. A soluble metalloendoprotease was demonstrated and characterized in sperm homogenates using the fluorogenic protease substrate succinyl-alanine-alanine-phenylalanine-4-aminomethylcoumarin. The protease was inhibited by the metal chelators EDTA and 1,10-phenanthroline, and activity of the inactive apoenzyme could be reconstituted with Zn2+. The metalloendoprotease substrate and inhibitors blocked the acrosome reaction induced either by egg jelly coat or by ionophore, but had no effect on the influx of Ca2+. These observations suggest that inhibition occurs at a step independent of Ca2+ entry. Overall, the results of this study provide strong indirect evidence that the acrosome reaction requires the action of metalloendoprotease.

  15. Superoxide anion production by human spermatozoa as a part of the ionophore-induced acrosome reaction process.

    Griveau, J F; Renard, P; Le Lannou, D


    The involvement of superoxide anion (O2o-) in human sperm capacitation and/or acrosome reaction was investigated. Addition of superoxide dismutase (SOD) to the medium at the beginning of the capacitation process or 15 min before induction of the acrosome reaction, decreased the level of ionophore-induced acrosome reaction. Hyperactivation was unaffected by the presence of SOD during the capacitation process. Addition of calcium ionophore to the sperm suspension increased production of O2o- by the spermatozoa by four to five-fold and induced the acrosome reaction. In the presence of SOD, superoxide anion could not be detected in the medium and the rate of induced-acrosome reaction was decreased greatly. The presence of an inhibitor of protein kinase C inhibited the production of O2o- in the medium and reduced the induced-acrosome reaction. The production of O2o- and the acrosome reaction were also increased by exposure of spermatozoa to 12-myristate 13-acetate phorbol ester, a specific activator of protein kinase C. While the level of spontaneous acrosome reaction was not increased by the direct addition of O2o- to the medium, its presence induced the release of unesterified fatty acids from membrane phospholipids. These findings suggest that the production of O2o- by spermatozoa could be involved in the ionophore-induced acrosome reaction, possibly through the de-esterification of membrane phospholipids. However, this production of superoxide anion is not sufficient on its own to induce the acrosome reaction.

  16. Changes of IZUMO1 in bull spermatozoa during the maturation, acrosome reaction, and cryopreservation.

    Fukuda, Masaki; Sakase, Mitsuhiro; Fukushima, Moriyuki; Harayama, Hiroshi


    To obtain basic information of bull IZUMO1 (a sperm protein essential for sperm-egg fusion) and disclose possible causes for the impaired fertilizing ability in bull cryopreserved spermatozoa, we investigated this protein in bull spermatozoa collected from various regions of epididymides, freshly ejaculated spermatozoa, acrosome-reacted spermatozoa, and cryopreserved spermatozoa by Western blotting and the triple staining with the anti-IZUMO1 antibody, fluorescein isothiocyanate-peanut agglutinin, and 4',6-diamidino-2-phenylindole. In the cauda epididymal spermatozoa and freshly ejaculated spermatozoa, bull IZUMO1 was detected mainly as a 45-kDa major form. This major form was derived probably from a 52-kDa precursor form in the epididymis. Bull IZUMO1 was immunolocalized along the border between the principal and equatorial segments of the acrosomal region (pattern P1 of IZUMO1) in the most of epididymal and freshly ejaculated spermatozoa with normal acrosomes. In the samples after the treatments to induce the acrosome reaction, the percentages of spermatozoa without acrosomes and with IZUMO1 in whole equatorial segment (pattern P2 of IZUMO1) significantly increased. These results indicate that bull IZUMO1 undergoes maturation-related changes during sperm transit through the epididymis and that it is translocated to the equatorial segment of acrosomal region during the acrosome reaction. On the other hand, severe damages were observed in the acrosomes of 60% of the cryopreserved spermatozoa. Localization of IZUMO1 in these spermatozoa was pattern P2 (IZUMO1 in whole equatorial segment), P3 (IZUMO1 in whole acrosomal region), or P4 (IZUMO was lost). Moreover, after the incubation to compare the stability of acrosomes and IZUMO1 localization between cryopreserved spermatozoa and freshly ejaculated spermatozoa, much more spermatozoa lost acrosomes and IZUMO1 in the cryopreserved samples compared with freshly ejaculated samples. These findings indicate that impaired

  17. Role of ions and ion channels in capacitation and acrosome reaction of spermatozoa

    SharadBPurohit; MaliniLaloraya; G.pradeepkumar


    Capacitation and acrosome reaction are important prerequisites of the fertilization process. Capacitation is a highlycomplex phenomenon occurring in the female genital tract, rendering the spermatozoa capable of binding and fusionwith the oocyte. During capacitation various biochemical and biophysical changes occur in the spermatozoa and thespermatozoal membranes. Ions and ion channels also play important roles in governing the process of capacitation bychanging the fluxes of different ions which in turn controls various characteristics of capacitated spermatozoa. Alongwith the mobilization of ions the generation of free radicals and efflux of cholesterol also plays an impo~.nt role in thecapacitation state of the spermatozoa. The generation of free radical and efflux of cholesterol change the mechano-dynamic properties of the membrane by oxidation of the polyunsaturated lipids and by generating the cholesterol freepatches. The process of capacitation renders the spermatozoa responsive to the inducers of the acrosome reaction. Theglycoprotein zona pellucida 3 (ZP3) of the egg coat zona pellucida is the potent physiological stimulator of the acro-some reaction; progesterone, a major component of the follicular fluid, is also an inducer of the acrosome reaction.The inducers of the acrosome reaction cause the activation of the various ion-channels leading to high influxes of calci-um, sodium and bicarbonate. The efflux of cholesterol during the process of capacitation alters the permeability of themembrane to the ions and generate areas which are prone to fusion and ve.siculation process during the acrosome reactioa. this review focuses mainly on effects of the ion and ion-channels, free radicals, and membrane fluidity changesduring the process of capacitation and acrosome reaction.

  18. Dynamics of the induced acrosome reaction in boar sperm evaluated by flow cytometry

    Birck, Anders; Labouriau, Rodrigo; Christensen, Preben


    The present study investigated the dynamics of the in vitro induced acrosome reaction (AR) in boar sperm in response to medium composition, incubation time and ionophore concentration. The AR is a prerequisite for normal sperm fertilizing capability and can be studied in vitro following induction...... induced AR. A detailed description of the dynamics of sperm viability and acrosomal status of boar sperm following in vitro induction of the AR has to our knowledge not previously been conducted. In the present study, a triple color flow cytometric detection technique was used, which gave simultaneous...... information on sperm viability and acrosomal status. The ionophore induced AR was dependent on extracellular Ca2+, but could be easily induced in boar sperm without capacitation. Capacitation-associated plasma membrane phospholipid scrambling was assessed and a medium specific ability to induce these membrane...

  19. Effect of NGF on the motility and acrosome reaction of golden hamster spermatozoa in vitro.

    Jin, WanZhu; Tanaka, Akane; Watanabe, Gen; Matsuda, Hiroshi; Taya, Kazuyoshi


    Motility and fertilizing ability are known to be two important physiological attributes of a mature sperm, yet the mechanism by which spermatozoa mature and become motile remains largely unknown. It has been shown that nerve growth factor (NGF) is a protein essential for the development, maintenance and survival of the peripheral and central nervous systems. However, the presence of high levels of NGF protein and mRNA do not correlate with the innervations by NGF sensitive fibers in tissues such as the testis, prostate and seminal vesicles. These observations have shifted the attention of research to the role of NGF outside of the nervous system. Here, we demonstrate that NGF and its receptors TrkA and p75 are widely expressed in the testis, accessory reproductive organ, and the epididymal sperms. We also show that NGF stimulates two important aspects of sperm functions, motility and the acrosome reaction, in a time- and dose-dependent manner. NGF activated the sperm cell acrosome reaction, while addition of inhibitors specific for MAPK kinase significantly blocked the sperm acrosome reaction. Taken together, our findings suggest that NGF plays an integral role in sperm motility and the acrosome reaction through, at least in part, the MAPK signalling pathway.

  20. Destabilization of acrosome and elastase influence mediate the release of secretory phospholipase A2 from human spermatozoa

    Jacqueline Leβig; Uta Reibetanz; Jürgen Arnhold; Hans-Jürgen Glander


    Aim: To determine the cellular distribution of secretory phospholipase A2 (sPLA2) in dependence on the acrosomal state and under the action of elastase released under inflammatory processes from leukocytes. Methods: Acrosome reaction of spermatozoa was triggered by calcimycin. Human leukocyte elastase was used to simulate in flammatory conditions. To visualize the distribution of sPLA2 and to determine the acrosomal state, immunofluorescence tech-niques and lectin binding combined with confocal laser scanning fluorescence microscopy and flow cytometry were used. Results: Although sPLA2 was detected at the acrosome and tail regions in intact spermatozoa, it disappearedfrom the head region after triggering the acrosome reaction. This release of sPLA2 was associated with enhanced binding of annexin V-fluoroscein isothiocyanate (FITC) to spermatozoa surfaces, intercalation of ethidium-homodimer L and bnding of FITC-iabelled concanavalin A at the acrosomal region. Spermatozoa from healthy subjects treated with elastase were characterized by release of sPLA2, disturbance of acrosome structure, and loss of vitality. Conclusion:The ability of spermatozoa to release secretory phospholipase A2 is related to the acrosomal state. Premature destabi-lization of the acrosome and loss of sPLA2 can occur during silent inflammations in the male genital tract. The distribution pattern of sPLA2 in intact spermatozoa might be an additional parameter for evaluating sperm quality.

  1. Relationship between plasma membrane Ca2+-ATPase activity and acrosome reaction in guinea pig sperm

    李明文; 陈大元


    The results obtained by biochemical measurement demonstrated for the first time that significant decrease of the plasma membrane Ca2+-ATPase activity occurred during capacitation and acrosome reaction of guinea pig sperm. Ethaorynic acid, one kind of Ca2+-ATPase antagonists, inhibited the plasma membrane Ca2+-ATPase activity, but calmodulin (50μg/mL) and trifluoperazine (200- 500μmol/L) did not, suggesting that calmodulin is not involved in ATP-driven Ca2+ efflux from sperm. However, calmodulin is involved in the control of Ca2+ influx. TFP, one kind of calmodulin antagonists, accelerated the acrosome reaction and Ca2+ uptake into sperm cells significantly. Ca2+-ATPase antagonists, quercetin, sodium orthovandate, furosemide and ethacrynic acid promoted the acrosome reaction, but inhibited Ca2+ uptake, which cannot be explained by their inhibitory effects on the plasma membrane Ca2+-ATPase activity. It is speculated that this phenomenon might be caused by simultaneous inhibitions of the activities of C

  2. Molecular basis of sperm capacitation acrosome reaction and interaction with eggs

    Sheikhnejad, G.


    A phospholipase C (PLC) which can hydrolyze /sup 14/C-phosphatidylcholine was purified from bull seminal plasma. This PLC has an optimum at pH 7.2 and its PI was about 5.0. The enzyme was inhibited by EDTA, Cd/sup 2 +/, Pb/sup 2 +/, Ni/sup 2 +/, Fe/sup 2 +/, and Zn/sup 2 +/. PLC consists of two subunits one 69,000 and the other 55,000 daltons. The purified PLC was examined for induction of capacitation and acrosome reaction of guinea pig spermatozoa. Sperm were examined for the acrosome reaction 10 min after addition of 3.4 mM Ca/sup 2 +/. Fifty percent of the sperm underwent the acrosome reaction while the control had less than 5% acrosome reacted sperm. The antiserum to the inneracrosomal membrane isolated from sperm was labeled with FITC conjugated goat anti-guinea pig IgG. The conjugated antibody was used to localize sperm antigens. The antigens located on the IAM were only fluoresced when rabbit sperm were treated with methanol and/or MgCl/sub 2/. Therefore anti-IAM antibody did not bind to the sperm plasma membrane. In vivo capacitated rabbit sperm were incubated with anti-IAM antibody (intact IgG and F(ab')/sub 2/ fragments) for 30 min prior to addition of rabbit eggs. After 24 h the eggs were examined for cleavage. The control eggs were fertilized (90%) while the antibody completely inhibited the fertilization of ova in vitro. The eggs incubated with antibody prior to the addition of sperm were still fertilizable. Thus, anti-IAM did not have any noticeable effect on the eggs. It was also shown that antibody inhibited fertilization of zona-free rabbit eggs in vitro as well.

  3. Insulin and leptin enhance human sperm motility, acrosome reaction and nitric oxide production

    Fanuel Lampiao; Stefan S. du Plessis


    Aim: To investigate the in vitro effects of insulin and leptin on human sperm motility, viability, acrosome reaction and nitric oxide (NO) production. Methods: Washed human spermatozoa from normozoospermic donors were treated with insulin (10 μIU) and leptin (10 nmol). Insulin and leptin effects were blocked by inhibition of their intracellular effector, phosphotidylinositol 3-kinase (PI3K), by wortmannin (10 μmol) 30 min prior to insulin and leptin being given. Computer-assisted semen analysis was used to assess motility after 1, 2 and 3 h of incubation. Viability was assessed by fluorescence-activated cell sorting using propidium iodide as a fluorescent probe. Acrosome-reacted cells were observed under a fluorescent microscope using fluorescein-isothiocyanate-Pisum sativum agglutinin as a probe. NO was measured after treating the sperm with 4,5-diaminofluorescein-2/diacetate (DAF-2/DA) and analyzed by fluorescence-activated cell sorting. Results: Insulin and leptin significantly increased total motility, progressive motility and acrosome reaction, as well as NO production. Conclusion: This study showed the in vitro beneficial effects of insulin and leptin on human sperm function. These hormones could play a role in enhancing the fertilization capacity of human spermatozoa.

  4. Induction of the acrosome reaction test to in vitro estimate embryo production in Nelore cattle

    M.Z. Costa


    Full Text Available The effectiveness of induction of the acrosome reaction (AR test as a parameter to in vitro estimate embryo production (IVP in Nelore breed and the AR pattern by the Trypan Blue/Giemsa (TB stain were evaluated. Frozen semen samples from ten Nelore bulls were submitted to AR induction and were also evaluated for cleavage and blastocyst rates. The treatments utilized for AR induction were: control (TALP medium, TH (TALP medium + 10μg heparin, TL (TALP medium + 100μg lysophosphatidylcholine and THL (TALP medium + 10μg heparin + 100μg lysophosphatidylcholine. Sperm acrosomal status and viability were evaluated by TB staining at 0 and after 4h incubation at 38°C. The results obtained for AR presented a significant difference (P<0.05 in the percentage of acrosome reacted live sperm after 4h of incubation in the treatments that received heparin. The cleavage and blastocyst rates were 60% and 38% respectively and a significant difference was observed among bulls (P<0.05. It was founded a satisfactory model to estimate the cleavage and blastocyst rates by AR induction test. Therefore, it can be concluded that the induction of the AR test is a valuable tool to predict the IVP in Nelore breed.

  5. Role and regulation of EGFR in actin remodeling in sperm capacitation and the acrosome reaction

    Haim Breitbart; Nir Etkovitz


    To bind and fertilize the egg,the spermatozoon should undergo few biochemical and motility changes in the female reproductive tract collectively called capacitation.The capacitated spermatozoon binds to the egg zona pellucida,and then undergoes the acrosome reaction(AR),which allows its penetration into the egg.The mechanisms regulating sperm capacitation and the AR are not completely understood.In the present review,we summarize some data regarding the role and regulation of the epidermal growth factor receptor(EGFR)in these processes.In the capacitation process,the EGFR is partially activated by protein kinase A(PKA),resulting in phospholipase D(PLD)activation and actin polymerization.Protein kinase C alpha(PKCα),which is already activated at the beginning of the capacitation,also participates in PLD activation.Further activation of the EGFR at the end of the capacitation enhances intracellular Ca2+concentration leading to F-actin breakdown and allows the AR to take place.Under in vivo conditions,the EGFR can be directly activated by its known ligand epidermal growth factor(EGF),and indirectly by activating PKA or by transactivation mediated by G protein-coupled receptors(GPCRs)activation or by ouabain.Under physiological conditions,sperm PKA is activated mainly by bicarbonate,which activates the soluble adenylyl cyclase to produce cyclic adenosine monophosphate(cAMP),the activator of PKA.The GPCR activators angiotensin ll or lysophosphatidic acid,as well as ouabain and EGF are physiological components present in the female reproductive tract.

  6. Mechanism of sperm capacitation and the acrosome reaction: role of protein kinases

    Debby Ickowicz; Maya Finkelstein; Haim Breitbart


    Mammalian sperm must undergo a series of biochemical and physiological modifications,collectively called capacitation,in the female reproductive tract prior to the acrosome reaction (AR).The mechanisms of these modifications are not well characterized though protein kinases were shown to be involved in the regulation of intracellular Ca2+ during both capacitation and the AR.In the present review,we summarize some of the signaling events that are involved in capacitation.During the capacitation process,phosphatidyl-inositol-3-kinase (P13K) is phosphorylated/activated via a protein kinase A (PKA)-dependent cascade,and downregulated by protein kinase C α (PKCα).PKCα is active at the beginning of capacitation,resulting in P13K inactivation.During capacitation,PKCα as well as PP1γ2 is degraded by a PKA-dependent mechanism,allowing the activation of P13K.The activation of PKA during capacitation depends mainly on cyclic adenosine monophosphate (cAMP) produced by the bicarbonate-dependent soluble adenylyl cyclase.This activation of PKA leads to an increase in actin polymerization,an essential process for the development of hyperactivated motility,which is necessary for successful fertilization.Actin polymerization is mediated by PIP2 in two ways:first,P(I)P2 acts as a cofactor for phospholipase D (PLD) activation,and second,as a molecule that binds and inhibits actin-severing proteins such as gelsolin.Tyrosine phosphorylation of gelsolin during capacitation by Src family kinase (SFK) is also important for its inactivation.Prior to the AR,gelsolin is released from P(I)P2 and undergoes dephosphorylation/activation,resulting in fast F-actin depolymerization,leading to the AR.

  7. Elucidation of the involvement of p14, a sperm protein during maturation, capacitation and acrosome reaction of caprine spermatozoa.

    Nandi, Pinki; Ghosh, Swatilekha; Jana, Kuladip; Sen, Parimal C


    Mammalian sperm capacitation is an essential prerequisite to fertilization. Although progress is being made in understanding the physiology and biochemistry of capacitation, little has been yet explored about the potential role(s) of individual sperm cell protein during this process. Therefore elucidation of the role of different sperm proteins in the process of capacitation might be of great importance to understand the process of fertilization. The present work describes the partial characterization of a 14-kDa protein (p14) detected in goat spermatozoa using an antibody directed against the purified protein. Confocal microscopic analysis reveals that the protein is present in both the intracellular and extracellular regions of the acrosomal and postacrosomal portion of caudal sperm head. Though subcellular localization shows that p14 is mainly cytosolic, however it is also seen to be present in peripheral plasma membrane and soluble part of acrosome. Immuno-localization experiment shows change in the distribution pattern of this protein upon induction of capacitation in sperm cells. Increased immunolabeling in the anterior head region of live spermatozoa is also observed when these cells are incubated under capacitating conditions, whereas most sperm cells challenged with the calcium ionophore A23187 to acrosome react, lose their labeling almost completely. Intracellular distribution of p14 also changes significantly during acrosome reaction. Interestingly, on the other hand the antibody raised against this 14-kDa sperm protein enhances the forward motility of caprine sperm cells. Rose-Bengal staining method shows that this anti-p14 antibody also decreases the number of acrosome reacted cells if incubated with capacitated sperm cells before induction of acrosome reaction. All these results taken together clearly indicate that p14 is intimately involved and plays a critical role in the acrosomal membrane fusion event.

  8. Elucidation of the involvement of p14, a sperm protein during maturation, capacitation and acrosome reaction of caprine spermatozoa.

    Pinki Nandi

    Full Text Available Mammalian sperm capacitation is an essential prerequisite to fertilization. Although progress is being made in understanding the physiology and biochemistry of capacitation, little has been yet explored about the potential role(s of individual sperm cell protein during this process. Therefore elucidation of the role of different sperm proteins in the process of capacitation might be of great importance to understand the process of fertilization. The present work describes the partial characterization of a 14-kDa protein (p14 detected in goat spermatozoa using an antibody directed against the purified protein. Confocal microscopic analysis reveals that the protein is present in both the intracellular and extracellular regions of the acrosomal and postacrosomal portion of caudal sperm head. Though subcellular localization shows that p14 is mainly cytosolic, however it is also seen to be present in peripheral plasma membrane and soluble part of acrosome. Immuno-localization experiment shows change in the distribution pattern of this protein upon induction of capacitation in sperm cells. Increased immunolabeling in the anterior head region of live spermatozoa is also observed when these cells are incubated under capacitating conditions, whereas most sperm cells challenged with the calcium ionophore A23187 to acrosome react, lose their labeling almost completely. Intracellular distribution of p14 also changes significantly during acrosome reaction. Interestingly, on the other hand the antibody raised against this 14-kDa sperm protein enhances the forward motility of caprine sperm cells. Rose-Bengal staining method shows that this anti-p14 antibody also decreases the number of acrosome reacted cells if incubated with capacitated sperm cells before induction of acrosome reaction. All these results taken together clearly indicate that p14 is intimately involved and plays a critical role in the acrosomal membrane fusion event.

  9. Involvement of zinc in the regulation of pHi, motility, and acrosome reactions in sea urchin sperm


    When sperm of Strongylocentrotus purpuratus or Lytechinus pictus are diluted into seawater, motility is initiated; and when exposed to egg jelly, an acrosome reaction is induced. In the presence of a variety of structurally different metal chelators (0.1-1 mM EDTA, EGTA, phenanthroline, dipyridyl, cysteine, or dithiothreitol), motility initiation is delayed and the acrosome reaction is inhibited. Of the metals detected in the sperm of these two species, very low levels of Zn+2 (0.1 microM fre...

  10. Assessment of released acrosin activity as a measurement of the sperm acrosome reaction

    Rui-Zhi Liu; Wan-Li Na; Hong-Guo Zhang; Zhi-Yong Lin; Bai-Oong Xue; Zong-Oe Xu


    Aim: To develop a method for assessing sperm function by measuring released acrosin activity during the acrosome reaction (AR). Methods: Human semen samples were obtained from 24 healthy donors with proven fertility after 3-7 days of sexual abstinence. After collection, samples were liquefied for 30 min at room temperature. Standard semen parameters were evaluated according to World Health Organization (WHO) criteria. Calcium ionophore A23187 and progesterone (P4) were used to stimulate the sperm to undergo AR. After treatment, sperm were incubated with the supravital dye Hoechst33258, fixed in a glutaraldehyde-phosphate-buffered saline solution, and the acrosomal status was determined by fluorescence microscopy with fluorescein isothiocyanate-labeled Pisum sativum agglutinin (FITC-PSA). The percentage of sperm undergoing AR (AR%) was compared to sperm acrosin activities as assessed by spectrocolorimetry. The correlation between AR% and acrosin activity was determined by statistical analysis. Results: The AR% and released acrosin activity were both markedly increased with A23187 and P4 stimulation. Sperm motility and viability were significantly higher after stimulation with P4 versus stimula-tion with A23187 (P < 0.001). There was a significant positive correlation between released acrosin activity and AR% determined by FITC-PSA staining (r = 0.916, P < 0.001). Conclusion: Spectrocolorimetric measurement of released acrosin activity might serve as a reasonable alternative method to evaluate AR.

  11. Kinetics of human sperm acrosomal exocytosis.

    Sosa, C M; Pavarotti, M A; Zanetti, M N; Zoppino, F C M; De Blas, G A; Mayorga, L S


    The acrosome reaction is a unique event in the lifespan of sperm characterized by the exocytosis of the acrosomal content and the release of hybrid vesicles formed by patches of the outer acrosomal membrane and the plasma membrane. This unique regulated exocytosis is mediated by essentially the same membrane fusion machinery present in neuroendocrine cells. However, whereas secretion in neuroendocrine cells occurs in less than a second, the acrosome reaction is normally assessed after several minutes of incubation with inducers. In this report, we measured the kinetics of human sperm exocytosis triggered by two stimuli (calcium ionophore and progesterone) by using electron microscopy and three different approaches based on the incorporation of fluorescent Pisum sativum agglutinin into the acrosome upon opening of fusion pores connecting the extracellular medium with the acrosomal lumen. The results with the different methods are consistent with a slow kinetics (t½ = 14 min). We also manipulated the system to measure different steps of the process. We observed that cytosolic calcium increased with a relatively fast kinetics (t½ = 0.1 min). In contrast, the swelling of the acrosomal granule that precedes exocytosis was a slow process (t½ = 13 min). When swelling was completed, the fusion pore opening was fast (t½ = 0.2 min). The results indicate that acrosomal swelling is the slowest step and it determines the kinetics of the acrosome reaction. After the swelling is completed, the efflux of calcium from intracellular stores triggers fusion pores opening and the release of hybrid vesicles in seconds.

  12. Fusion of artificial membranes with mammalian spermatozoa. Specific involvement of the equatorial segment after acrosome reaction.

    Arts, E G; Kuiken, J; Jager, S; Hoekstra, D


    The fusogenic properties of bovine and human spermatozoa membranes were investigated, using phospholipid bilayers (liposomes) as target membranes. Fusion was monitored by following lipid mixing, as revealed by an assay based on resonance-energy transfer. In addition, fusion was visualized by fluorescence microscopy, using fluorescent lipid vesicles. Cryopreserved bovine sperm fused with liposomes before induction of the acrosome reaction, fluorescence being located in essentially all spermatozoa membrane domains. Fresh bovine and human spermatozoa fused with liposomes only after the induction of the acrosome reaction, as triggered by calcium ionophore A23187 or zonae pellucidae (proteins), while the fluorescence distribution was mainly restricted to the equatorial segment (ES). However, with spermatozoa that had undergone a freeze/thawing cycle, domains other than ES also became labeled. Hence, the redistribution of the lipid probes over the entire membrane occurring during lipid mixing with cryopreserved bovine sperm is probably related to membrane perturbations caused by long-term cryopreservation. Fusion with liposomes was governed by spermatozoa factors and required the presence of acidic phospholipids like cardiolipin and phosphatidylserine in the liposomal bilayer. Incorporation of the zwitterionic lipid phosphatidylcholine in the vesicles inhibited the fusion reaction. Fusion was pH dependent. The results indicate that the ES is the primary domain of spermatozoa membranes that harbours the fusogenic capacity of sperm. Liposomes appear a valuable tool in further characterizing the properties of this domain, which has been claimed [Yanagimachi, R. (1988) in The physiology of reproduction (Knobil, E. & Neill, J., eds) pp. 135-185, Raven Press, New York] to represent the putative, initial fusion site for the oocyte.

  13. Identification of egg-jelly substances triggering sperm acrosome reaction in the newt, Cynops pyrrhogaster.

    Watanabe, Akihiko; Fukutomi, Keiko; Kubo, Hideo; Ohta, Manami; Takayama-Watanabe, Eriko; Onitake, Kazuo


    Our previous studies have shown that the acrosome reaction (AR) occurs in egg-jelly of the Japanese newt, Cynops pyrrhogaster. This is analogous to the substances of echinoderms but distinct from those of many other vertebrates derived from the egg envelope or its derivative, the zona pellucida. To identify the AR-inducing substances in newt egg jelly, a monoclonal antibody (mAb) was generated against the jelly by screening the culture supernatants to find the one that best neutralized the AR-inducing activity of the jelly substance. The mAb specifically reacted to protein bands in the jelly. These proteins, with apparent molecular weights of 122 and 90 kDa, exhibited AR-inducing activity, indicating that they are definitely AR-inducing substances. Western blotting using the mAb indicated that the 122 and 90 kDa proteins are present only in the egg jelly's outermost layer, where AR-inducing activity is known to occur. Both proteins were recognized with wheat germ agglutinin (WGA), a lectin that inhibits AR-induction in egg jelly extract. Taken together, these findings indicate that the 122 and 90 kDa proteins are the AR-inducing substances in the egg jelly of C. pyrrhogaster. The WGA recognition of the proteins was lost by N-glycosidase digestion, suggesting that N-linked carbohydrate moieties in these proteins may be responsible for the AR-inducing activity.

  14. Sperm from hyh mice carrying a point mutation in alphaSNAP have a defect in acrosome reaction.

    Luis Federico Bátiz

    Full Text Available Hydrocephalus with hop gait (hyh is a recessive inheritable disease that arose spontaneously in a mouse strain. A missense mutation in the Napa gene that results in the substitution of a methionine for isoleucine at position 105 (M105I of alphaSNAP has been detected in these animals. alphaSNAP is a ubiquitous protein that plays a key role in membrane fusion and exocytosis. In this study, we found that male hyh mice with a mild phenotype produced morphologically normal and motile sperm, but had a strongly reduced fertility. When stimulated with progesterone or A23187 (a calcium ionophore, sperm from these animals had a defective acrosome reaction. It has been reported that the M105I mutation affects the expression but not the function of the protein. Consistent with an hypomorphic phenotype, the testes and epididymides of hyh mice had low amounts of the mutated protein. In contrast, sperm had alphaSNAP levels indistinguishable from those found in wild type cells, suggesting that the mutated protein is not fully functional for acrosomal exocytosis. Corroborating this possibility, addition of recombinant wild type alphaSNAP rescued exocytosis in streptolysin O-permeabilized sperm, while the mutant protein was ineffective. Moreover, addition of recombinant alphaSNAP. M105I inhibited acrosomal exocytosis in permeabilized human and wild type mouse sperm. We conclude that the M105I mutation affects the expression and also the function of alphaSNAP, and that a fully functional alphaSNAP is necessary for acrosomal exocytosis, a key event in fertilization.

  15. Fucose, mannose, and β-N-acetylglucosamine glycopolymers initiate the mouse sperm acrosome reaction through convergent signaling pathways.

    Wu, Linghui; Sampson, Nicole S


    The sperm acrosome reaction (AR), an essential exocytosis step in mammalian fertilization, is mediated by a species-specific interaction of sperm surface molecules with glycans on the egg. Previous studies indicate that a subset of terminal carbohydrates on the mouse egg zona pellucida (ZP) trigger the AR by cross-linking or aggregating receptors on the sperm membrane. However, the exact role of those carbohydrates in AR has not been identified and the mechanism underlying the AR still needs further investigation. To study this process, a series of glycopolymers was synthesized. The glycopolymers are composed of a multivalent scaffold (norbornene), a functional ligand (previously identified ZP terminal monosaccharides), and a linker connecting the ligand and the scaffold. The polymers were tested for their ability to initiate AR and through which signaling pathways AR induction occurred. Our data demonstrate that mannose, fucose, and β-N-acetylglucosamine 10-mers and 100-mers initiate AR in a dose-dependent manner, and the 100-mers are more potent on a per monomer basis than the 10-mers. Although nearly equipotent in inducing the AR at the optimal concentrations, their AR activation kinetics are not identical. Similar to mouse ZP3, all 100-mer-activated AR are sensitive to guanine-binding regulatory proteins (G-proteins), tyrosine kinase, protein kinase A, protein kinase C, and Ca(2+)-related antagonists. Thus, the chemotypes of synthetic glycopolymers imitate the physiologic AR-activation agents and provide evidence that occupation of one of at least three different receptor binding sites is sufficient to initiate the AR.

  16. GABA/progesterone-induced polyphosphoinositide (PPI) breakdown and its role in the acrosome reaction of guinea pig spermatozoa in vitro


    To investigate whether GABA/progesterone (P4) stimulates PPI breakdown and its role in the acrosome reaction (AR), spermatozoa of guinea pig were preincubated in MCM-LCa2+ for 5.5 h and then labeled with [32P]pi for 1 h. Samples were washed through a three-step gradient Percoll, adjusted to 5×107 cells/mL and exposed to 2 mmol/L Ca2+, 5 mmol/L GABA, 10 mmol/L P4 and other agents. Lipids were separated by t.l.c. and radioactivity in spots determined by scintillation counting. The AR was assessed by phase-contrast microscopy. The results showed that (i) when spermato-zoa were treated with GABA, 32P-label diminished rapidly in phosphatidylinositol 4, 5-bisphosphate (PIP2), phosphatidylinositol 4-phosphate (PIP), and increased in phosphatidic acid (PA). The loss of label from PPI was almost completed by 10 min. The time-course of the AR was much slower than PPI when spermatozoa reached a maximal response by 15 min; (ii) the pattern of PPI hydrolysis and stimulation of AR was similar for the three agonists tested;their potency followed the order A23187>progesterone≥GABA; (iii) GABA-induced PIP2 hydrolysis and rise in PA and the AR were prevented by inclusion of 10 mmol/L neomycin; (iv) the loss of PIP2 labeling and the increase in PA labeling abolished when spermatozoa were exposed to EGTA or Ca2+ channel blocker. These re-sults indicate that GABA or P4-induced PPI breakdown is an important and essential event in the series of changes to membrane fusion during the AR of guinea pig spermatozoa and this effect is mediated via calcium by activation of phosphatidylinositol-specific phospholipase C.

  17. Acrosome reaction is impaired in spermatozoa of obese men: a preliminary study.

    Samavat, Jinous; Natali, Ilaria; Degl'Innocenti, Selene; Filimberti, Erminio; Cantini, Giulia; Di Franco, Alessandra; Danza, Giovanna; Seghieri, Giuseppe; Lucchese, Marcello; Baldi, Elisabetta; Forti, Gianni; Luconi, Michaela


    To compare spontaneous (Sp-AR) and P-induced acrosome reaction (AR) in spermatozoa of obese and lean subjects. Bariatric unit at a university hospital. Prospective, observational study. Twenty-three obese (mean±SD body mass index [BMI], 44.3±5.9 kg/m2) and 25 age-matched lean (BMI, 24.2±3.0 kg/m2) subjects. None. Spontaneous and P-induced AR in spermatozoa of obese and lean subjects. A statistically significant difference was found between obese and lean cohorts in total T and calculated free T, E2, glycated hemoglobin, and high-density lipoproteins, whereas among the routine semen parameters analyzed, only immotile sperm percentage and ejaculate volume differed significantly. Spermatozoa of obese (n=13) vs. lean men (n=19) showed a higher Sp-AR (17.9%±7.2% vs. 8.3%±4.2%), which resulted in a reduced ability to respond to P evaluated as the AR-after-P-challenge parameter (3.5%±3.2% vs. 17.6%±9.2%). Multivariate analysis adjusted for age revealed a significant correlation between BMI, waist, E2, and glycated hemoglobin with both Sp-AR (age-adjusted r=0.654, r=0.711, r=0.369, and r=0.644, respectively) and AR-after-P-challenge (age-adjusted r=-0.570, r=-0.635, r=-0.507, and r=-0.563, respectively). A significant difference in sperm cholesterol content was reported between obese and lean men (29.8±19.5 vs. 19.1±14.6 ng/μg of proteins). Sperm AR is impaired in obese men, showing reduced response to P and elevated Sp-AR, associated with altered circulating levels of E2 and sperm cholesterol content. Copyright © 2014 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  18. Effect of two ram sperm capacitating media on acrosome reaction and zona-free hamster oocyte penetration test

    Silvia Ferrari


    Full Text Available An in vitro zona-free hamster oocyte penetration test was utilized in 24 trials in order to evaluate the capacitation media used for ram sperm. A pool of fresh semen was collected from three crossed breed rams. Two semen drops were washed by centrifugation and incubated in high ionic strength treatment (HIS or in a defined medium with HEPES, on heat ewe serum and heparin. After the incubation to promote capacitation, simplified triple-stain technique was used to evaluate the spontaneous acrosome reaction of the capacitated sperm. Superovulation in 96 golden hamsters was induced by PMSG and hCG. The oocytes were treated with hyaluronidase and trypsin to remove, respectively, the cumulus cells and the zona pellucida. Oocytes and capacitated sperm were incubated during 3 hours for further penetration. Then, oocytes were fixed and stained, being evaluated under phase contrast microscope. No significant statistical difference (p >; 0.05 was found between media, concerning the penetration rate of the capacitated sperm and between number of sperm viable with acrosome reaction after the capacitation treatment using two different media. It was concluded that both media utilized were effective in capacitating ram sperm.

  19. Surface mapping of binding of oviductin to the plasma membrane of golden hamster spermatozoa during in vitro capacitation and acrosome reaction.

    Kan, Frederick W K; Esperanzate, Patrick W B


    Oviductins are high-molecular-weight glycoproteins synthesized and secreted by nonciliated oviductal epithelial cells and have been shown to play a role in fertilization and early embryo development. The present study was carried out to examine the in vitro binding capacity of hamster oviductin to homologous sperm and to determine the sites of its localization in untreated, capacitated, and acrosome-reacted spermatozoa. Freshly prepared epididymal and capacitated sperm as well as acrosome-reacted sperm were incubated with oviductal fluid prepared from isolated hamster oviducts, fixed and then probed with a monoclonal antibody against hamster oviductin. Results obtained with pre-embedding immunolabeling experiments revealed binding of oviductin to the acrosomal cap and the apical aspect of the postacrosomal region. Immunolabeling of both regions appeared to be more intense in capacitated spermatozoa. Acrosome-reacted sperm showed an immunoreaction of moderate intensity over the postacrosomal region. The plasma membrane overlying the equatorial segment also exhibited a weak labeling. Quantitative analysis obtained with the surface replica technique indicated that oviductin had a higher binding affinity for the acrosomal cap than the postacrosomal region and that the binding of oviductin to the latter plasma membrane domain was enhanced during capacitation. Binding of oviductin to the postacrosomal region, however, was attenuated after acrosome reaction. Immunolabeling for oviductin was found to be the weakest over the equatorial segment regardless of the experimental conditions. The binding of hamster oviductin to specific membrane domains of the homologous sperm and the changes in its distribution during capacitation and acrosome reaction may be important for the function of hamster oviductin preceding and during fertilization.

  20. Acrosome Reaction and Ca2+ Imaging in Single Human Spermatozoa: New Regulatory Roles of [Ca2+]i1

    Sánchez-Cárdenas, Claudia; Servín-Vences, Martha Rocio; José, Omar; Treviño, Claudia Lydia; Hernández-Cruz, Arturo; Darszon, Alberto


    ABSTRACT The spermatozoa acrosome reaction (AR) is essential for mammalian fertilization. Few methods allow visualization of AR in real time together with Ca2+ imaging. Here, we show that FM4-64, a fluorescent dye used to follow exocytosis, reliably reports AR progression induced by ionomycin and progesterone in human spermatozoa. FM4-64 clearly delimits the spermatozoa contour and reports morphological cell changes before, during, and after AR. This strategy unveiled the formation of moving tubular appendages, emerging from acrosome-reacted spermatozoa, which was confirmed by scanning electron microscopy. Alternate wavelength illumination allowed concomitant imaging of FM4-64 and Fluo-4, a Ca2+ indicator. These AR and intracellular Ca2+ ([Ca2+]i) recordings revealed that the presence of [Ca2+]i oscillations, both spontaneous and progesterone induced, prevents AR in human spermatozoa. Notably, the progesterone-induced AR is preceded by a second [Ca2+]i peak and ∼40% of reacting spermatozoa also manifest a slow [Ca2+]i rise ∼2 min before AR. Our findings uncover new AR features related to [Ca2+]i. PMID:25100708

  1. P38 participates in spermatogenesis and acrosome reaction prior to fertilization in Chinese mitten crab Eriocheir sinensis.

    Zhu, Ming; Sun, Wen-Juan; Wang, Yuan-Li; Li, Qing; Yang, Hong-Dan; Duan, Ze-Lin; He, Lin; Wang, Qun


    P38 mitogen-activated protein kinases (MAPKs) comprise a family of serine/threonine protein kinases that play important roles in cellular responses to inflammatory cytokines and environmental stresses. These kinases are involved in controlling cell division, differentiation and death in mammalian testes and therefore are critical to spermatogenesis. To explore their functions in male reproduction of Chinese mitten crabs, Eriocheir sinensis p38 (Es-p38) protein expression was determined in different tissues including testes at different developmental stages by Western blot. Es-p38 was expressed in various tissues, with higher levels in the heart, stomach, gills and testes. Total Es-p38 protein levels increased gradually during spermatogenesis, but phosphorylated Es-p38 was much higher in the spermatid (August-October) than the spermatocyte (July-August) and sperm (October-January) stages. Trypan blue staining and hematoxylin/eosin staining were both used to detect sperm motility and changes in sperm morphology during the acrosome reaction (AR) induced by pre-incubation with A23187 in vitro, activated Es-p38 proteins detected by fluorescent microscopy were translocated gradually to nuclear and apical cap regions, accumulating at the anterior of the acrosomal tubule. The results suggest the involvement of p38 MAPK in spermatogenesis and the AR in E. sinensis.

  2. Dose-response effects of estrogenic mycotoxins (zearalenone, alpha- and beta-zearalenol on motility, hyperactivation and the acrosome reaction of stallion sperm

    Colenbrander Ben


    Full Text Available Abstract Background The aim of this study was to investigate the in vitro effects of the Fusarium fungus-derived mycotoxin, zearalenone and its derivatives alpha-zearalenol and beta-zearalenol on motility parameters and the acrosome reaction of stallion sperm. Since the toxic effects of zearalenone and its derivatives are thought to result from their structural similarity to 17beta-estradiol, 17beta-estradiol was used as a positive control for 'estrogen-like' effects. Methods Stallion spermatozoa were exposed in vitro to zearalenone, alpha-zearalenol, beta-zearalenol or 17beta-estradiol at concentrations ranging from 1 pM - 0.1 mM. After 2 hours exposure, motility parameters were evaluated by computer-assisted analysis, and acrosome integrity was examined by flow cytometry after staining with fluoroscein-conjugated peanut agglutinin. Results Mycotoxins affected sperm parameters only at the highest concentration tested (0.1 mM after 2 hours exposure. In this respect, all of the compounds reduced the average path velocity, but only alpha-zearalenol reduced percentages of motile and progressively motile sperm. Induction of motility patterns consistent with hyperactivation was stimulated according to the following rank of potency: alpha-zearalenol >17beta-estradiol > zearalenone = beta-zearalenol. The hyperactivity-associated changes observed included reductions in straight-line velocity and linearity of movement, and an increase in the amplitude of lateral head displacement, while curvilinear velocity was unchanged. In addition, whereas alpha- and beta- zearalenol increased the percentages of live acrosome-reacted sperm, zearalenone and 17beta-estradiol had no apparent effect on acrosome status. In short, alpha-zearalenol inhibited normal sperm motility, but stimulated hyperactive motility in the remaining motile cells and simultaneously induced the acrosome reaction. Beta-zearalenol induced the acrosome reaction without altering motility

  3. Dose-response effects of estrogenic mycotoxins (zearalenone, alpha- and beta-zearalenol) on motility, hyperactivation and the acrosome reaction of stallion sperm


    Background The aim of this study was to investigate the in vitro effects of the Fusarium fungus-derived mycotoxin, zearalenone and its derivatives alpha-zearalenol and beta-zearalenol on motility parameters and the acrosome reaction of stallion sperm. Since the toxic effects of zearalenone and its derivatives are thought to result from their structural similarity to 17beta-estradiol, 17beta-estradiol was used as a positive control for 'estrogen-like' effects. Methods Stallion spermatozoa were exposed in vitro to zearalenone, alpha-zearalenol, beta-zearalenol or 17beta-estradiol at concentrations ranging from 1 pM - 0.1 mM. After 2 hours exposure, motility parameters were evaluated by computer-assisted analysis, and acrosome integrity was examined by flow cytometry after staining with fluoroscein-conjugated peanut agglutinin. Results Mycotoxins affected sperm parameters only at the highest concentration tested (0.1 mM) after 2 hours exposure. In this respect, all of the compounds reduced the average path velocity, but only alpha-zearalenol reduced percentages of motile and progressively motile sperm. Induction of motility patterns consistent with hyperactivation was stimulated according to the following rank of potency: alpha-zearalenol >17beta-estradiol > zearalenone = beta-zearalenol. The hyperactivity-associated changes observed included reductions in straight-line velocity and linearity of movement, and an increase in the amplitude of lateral head displacement, while curvilinear velocity was unchanged. In addition, whereas alpha- and beta- zearalenol increased the percentages of live acrosome-reacted sperm, zearalenone and 17beta-estradiol had no apparent effect on acrosome status. In short, alpha-zearalenol inhibited normal sperm motility, but stimulated hyperactive motility in the remaining motile cells and simultaneously induced the acrosome reaction. Beta-zearalenol induced the acrosome reaction without altering motility. Conversely, zearalenone and 17beta

  4. Con A-binding protein Zn-α2-glycoprotein on human sperm membrane is related to acrosome reaction and sperm fertility.

    Liu, Y; Qu, F; Cao, X; Chen, G; Guo, Q; Ying, X; Guo, W; Lu, L; Ding, Z


    Fertilization, the recognition and fusion between spermatozoa and oocyte, involves various molecules on the spermatozoa and oocyte membranes. Concanavalin A (ConA)-binding proteins may be one of the molecules involved in mammal spermatozoa fertilization; however, their structure and function remain largely unknown. Here, we initially identified a ConA-binding protein, Zn-α2-glycoprotein (ZAG), involved in regulating the acrosome reaction (AR) of human spermatozoa. ZAG is localized on the pre-equatorial region covering the acrosome, neck and tail (some parts of middle piece and principal piece respectively) regions of the acrosome intact human spermatozoa, and disappears in the acrosomal region of the acrosome-reacted spermatozoa. Polyclonal antibodies against human recombinant ZAG significantly reduced the AR and sperm capability binding to human zona pellucida or penetration into zona-free hamster oocytes. Furthermore, assessment of the signaling pathways regulated by ZAG revealed that ZAG affects sperm AR through both the cAMP/PKA and PKC pathways. These results indicate that ZAG, which is present on the human sperm membrane, plays a critical role in the AR and subsequently, may be involved in sperm fertility.

  5. Effects of ubiquitin-protea some pathway on mouse sperm capacitation, acrosome reaction and in vitro fertilization


    Chlortetracycline (CTC) fluorescence patterns were used to study changes in the patterns B and AR of mouse sperm after incubation with reagents that would block the UPP. They were the monoclonal antibody against ubiquitinated proteins-UCP1; the polyclonal antibody against ubiquitin anti-Ub, and a special inhibitor against proteasome ALLN. Furthermore, we treated the capacitated sperm or the eggs with these reagents separately and tested whether the normal in vitro fertilization was blocked or not. Results illustrate that UCP1, anti-Ub, and ALLN have little effects on sperm capacitation and acrosome reaction,but they do inhibit fusion of mouse sperm with eggs, which suggests that UPP play an important role in mouse in vitro fertilization.``

  6. RIM, Munc13, and Rab3A interplay in acrosomal exocytosis

    Bello, Oscar D.; Zanetti, M. Natalia [Laboratorio de Biologia Celular y Molecular, Instituto de Histologia y Embriologia, IHEM (CONICET-UNCuyo), Facultad de Ciencias Medicas (Argentina); Laboratorio de Biologia Reproductiva, Instituto de Histologia y Embriologia, IHEM (CONICET-UNCuyo), Facultad de Ciencias Medicas (Argentina); Mayorga, Luis S. [Laboratorio de Biologia Celular y Molecular, Instituto de Histologia y Embriologia, IHEM (CONICET-UNCuyo), Facultad de Ciencias Medicas (Argentina); Michaut, Marcela A., E-mail: [Laboratorio de Biologia Reproductiva, Instituto de Histologia y Embriologia, IHEM (CONICET-UNCuyo), Facultad de Ciencias Medicas (Argentina); Instituto de Ciencias Basicas, Universidad Nacional de Cuyo, Mendoza (5500) (Argentina)


    Exocytosis is a highly regulated, multistage process consisting of multiple functionally definable stages, including recruitment, targeting, tethering, priming, and docking of secretory vesicles with the plasma membrane, followed by calcium-triggered membrane fusion. The acrosome reaction of spermatozoa is a complex, calcium-dependent regulated exocytosis. Fusion at multiple sites between the outer acrosomal membrane and the cell membrane causes the release of the acrosomal contents and the loss of the membranes surrounding the acrosome. Not much is known about the molecules that mediate membrane docking in this particular fusion model. In neurons, the formation of the ternary RIM/Munc13/Rab3A complex has been suggested as a critical component of synaptic vesicles docking. Previously, we demonstrated that Rab3A localizes to the acrosomal region in human sperm, stimulates acrosomal exocytosis, and participates in an early stage during membrane fusion. Here, we report that RIM and Munc13 are also present in human sperm and localize to the acrosomal region. Like Rab3A, RIM and Munc13 participate in a prefusion step before the efflux of intra-acrosomal calcium. By means of a functional assay using antibodies and recombinant proteins, we show that RIM, Munc13 and Rab3A interplay during acrosomal exocytosis. Finally, we report by electron transmission microscopy that sequestering RIM and Rab3A alters the docking of the acrosomal membrane to the plasma membrane during calcium-activated acrosomal exocytosis. Our results suggest that the RIM/Munc13/Rab3 A complex participates in acrosomal exocytosis and that RIM and Rab3A have central roles in membrane docking. -- Highlights: Black-Right-Pointing-Pointer RIM and Munc13 are present in human sperm and localize to the acrosomal region. Black-Right-Pointing-Pointer RIM and Munc13 are necessary for acrosomal exocytosis. Black-Right-Pointing-Pointer RIM and Munc13 participate before the acrosomal calcium efflux. Black

  7. Mouse sperm patch-clamp recordings reveal single Cl- channels sensitive to niflumic acid, a blocker of the sperm acrosome reaction.

    Espinosa, F; de la Vega-Beltrán, J L; López-González, I; Delgado, R; Labarca, P; Darszon, A


    Ion channels lie at the heart of gamete signaling. Understanding their regulation will improve our knowledge of sperm physiology, and may lead to novel contraceptive strategies. Sperm are tiny (approximately 3 microm diameter) and, until now, direct evidence of ion channel activity in these cells was lacking. Using patch-clamp recording we document here, for the first time, the presence of cationic and anionic channels in mouse sperm. Anion selective channels were blocked by niflumic acid (NA) (IC50 = 11 microM). The blocker was effective also in inhibiting the acrosome reaction induced by the zona pellucida, GABA or progesterone. These observations suggest that Cl- channels participate in the sperm acrosome reaction in mammals.

  8. A Unique 2-Sulfated β-Galactan from the Egg Jelly of the Sea Urchin Glyptocidaris crenularis: CONFORMATION FLEXIBILITY VERSUS INDUCTION OF THE SPERM ACROSOME REACTION*

    Castro, Michelle O.; Pomin, Vitor H.; Santos, Livia L.; Ana-Cristina E.S. Vilela-Silva; Hirohashi, Noritaka; Pol-Fachin, Laércio; Verli,Hugo; Mourão, Paulo A. S.


    Sulfated polysaccharides from the egg jelly of sea urchins act as species-specific inducers of the sperm acrosome reaction, which is a rare molecular mechanism of carbohydrate-induced signal-transduction event in animal cells. The sea urchin polysaccharides differ in monosaccharide composition (l-fucose or l-galactose), glycosylation, and sulfation sites, but they are always in the α-anomeric configuration. Herein, structural analysis of the polysaccharide from the sea urchin Glyptocidaris cr...

  9. Relationship between seminal plasma zinc concentration and spermatozoa–zona pellucida binding and the ZP-induced acrosome reaction in subfertile men

    Liu, De-Yi; Sie, Boon-Shih; Liu, Ming-Li; Agresta,Franca; Baker, HW Gordon


    The aim of this study was to determine the relationship between seminal zinc concentration and spermatozoa–zona pellucida (ZP) binding and the ZP-induced acrosome reaction (ZPIAR) in subfertile men. Semen analyses and seminal zinc concentration assessments were carried out according to the World Health Organization manual for 458 subfertile men. A spermatozoa–ZP interaction test was carried out by incubating 2 × 106 motile spermatozoa with a group of four unfertilized oocytes obtained from a ...

  10. Structural requirements for species-specific induction of the sperm acrosome reaction by sea urchin egg sulfated fucan.

    Hirohashi, Noritaka; Vilela-Silva, Ana-Cristina E S; Mourão, Paulo A S; Vacquier, Victor D


    The sulfated fucan (SF) of egg jelly induces the acrosome reaction (AR) of sea urchin sperm. Strongylocentrotus franciscanus (Sf) SF is sulfated only at the 2-position. Strongylocentrotus purpuratus (Sp) has two SF isotypes, each one being female specific. One is rich in sulfate at both the 2- and 4-positionS (SF-1), and the other is rich in sulfate at the 4-position, but not the 2-position (SF-2). Sf SF is poor at inducing the AR of Sp sperm, presumably due to lack of 4-sulfation. Sp SF-1 is better at inducing the AR of Sf sperm than Sp SF-2, hypothetically due to increased 2-sulfation. Chemical oversulfation of Sf SF increases the percentage of AR of Sp sperm, showing that 4-sulfation is important for recognition of SF by Sp sperm. Chemically oversulfated Sp SF-2 is better at inducing the Sf sperm AR, presumably because of increased 2-sulfation. The species, Strongylocentrotus drobachiensis (Sd), has an SF-2 that is exclusively 2-sulfated (like Sf), except the glycosidic linkage in Sd is alpha(1-->4), whereas in Sf it is alpha(1-->3). Sd SF-2 does not induce the AR of Sf sperm, showing the strict requirement for the alpha(1-->3) linkage in recognition between Sf sperm and SF. Egg jelly from Echinometra lucunter (El) contains sulfated galactan (SG) which differs from Sf SF only in that the monosaccharide is L-galactose, not L-fucose. This SG and Sf SF are equally potent in inducing the AR of Sf sperm, showing that modification at C6 of L-fucose is not important for proper recognition between SF and Sf sperm receptors. This system permits study of the structural basis for recognition between sulfated polysaccharide and receptors controlling signal transduction pathways in animal cells.

  11. The opening of maitotoxin-sensitive calcium channels induces the acrosome reaction in human spermatozoa: differences from the zona pellucida

    Julio C Chávez; Claudia L Trevi(n)o; Gerardo A de Blas; José L de la Vega-Beltrán; Takuya Nishigaki; Mayel Chirinos; María Elena González-González; Fernando Larrea; Alejandra Solís; Alberto Darszon


    The acrosome reaction(AR),an absolute requirement for spermatozoa and egg fusion,requires the influx of Ca2+into the spermatozoa through voltage-dependent Ca2+channels and store-operated channels.Maitotoxin(MTx),a Ca2+-mobilizing agent,has been shown to be a potent inducer of the mouse sperm AR,with a pharmacology similar to that of the zona pellucida(ZP),possibly suggesting a common pathway for both inducers.Using recombinant human ZP3(rhZP3),mouse ZP and two MTx channel blockers(U73122 and U73343),we investigated and compared the MTx-and ZP-induced ARs in human and mouse spermatozoa.Herein,we report that MTx induced AR and elevated intracellular Ca2+([Ca2+]1)in human spermatozoa,both of which were blocked by U73122 and U73343.These two compounds also inhibited the MTx-induced AR in mouse spermatozoa.In disagreement with our previous proposal,the AR triggered by rhZP3 or mouse ZP was not blocked by U73343,indicating that in human and mouse spermatozoa,the AR induction by the physiologicalligands or by MTx occurred through distinct pathways.U73122,but not U73343(inactive analogue),can block phospholipase C(PLC).Another PLC inhibitor,edelfosine,also blocked the rhZP3-and ZP-induced ARs.These findings confirmed the participation of a PLC-dependent signalling pathway in human and mouse zona protein-induced AR.Notably,edelfosine also inhibited the MTx-induced mouse sperm AR but not that of the human,suggesting that toxin-induced AR is PLC-dependent in mice and PLC-independent in humans.

  12. Cryopreservation of human spermatozoa. I. Effects of holding procedure and seeding on motility, fertilizability, and acrosome reaction.

    Critser, J K; Huse-Benda, A R; Aaker, D V; Arneson, B W; Ball, G D


    Three experiments were conducted to evaluate effects of holding semen at +5.0 degrees C for 30 minutes or -5.0 degrees C for 10 minutes and ice crystal induction (seeding) on frozen-thawed human spermatozoa. In experiment 1, spermatozoa were frozen, and postthaw motility was evaluated immediately (0 hour) and 24 hours later. At both 0 and 24 hours, nonfrozen control samples had higher motility than all other treatment groups. At 0 hour postthaw, motility was higher in samples held at -5.0 degrees C for 10 minutes with no significant effect of seeding. At 24 hours, samples held at -5.0 degrees C for 10 minutes and seeded, but not samples held at -5.0 degrees C and not seeded, had higher motility than samples held at +5.0 degrees C. In experiment 2, semen samples were frozen, and fertilizability was evaluated in a zona-free hamster egg penetration assay. Seeded samples had a higher frequency of sperm penetration than either nonfrozen or nonseeded samples. In experiment 3, nonfrozen controls and frozen treatment groups were evaluated for the frequency of survival and acrosomal integrity. Seeded samples had higher frequencies of survival and loss of acrosomal integrity than nonseeded samples. All frozen-thawed samples had a lower frequency of survival and a higher frequency of loss of acrosomal integrity than nonfrozen controls. Although altered patterns of fertilizability and acrosomal integrity are induced, collectively these data suggest that incorporating a holding temperature of -5.0 degrees C for 10 minutes and seeding may result in a superior protocol for freezing human spermatozoa.

  13. Kinetics of onset of mouse sperm acrosome reaction induced by solubilized zona pellucida: fluorimetric determination of loss of pH gradient between acrosomal lumen and medium monitored by dapoxyl (2-aminoethyl) sulfonamide and of intracellular Ca(2+) changes monitored by fluo-3.

    Rockwell, P L; Storey, B T


    The onset of the zona pellucida-induced acrosome reaction in mouse sperm is marked by loss of the pH gradient existing in acrosome-intact sperm between the acidic acrosomal lumen and the suspending medium, due to pore formation between outer acrosomal and plasma membranes. In earlier work, it was shown that this pH gradient loss occurred in single sperm bound to structurally intact zonae pellucidae with a half-time of 2.1 min; the extended kinetics of this loss determined in a sperm population bound to intact zonae was due to a 180-min range of variable lag times. We hypothesized that this lag time range was due to steric constraints imposed by the three-dimensional structure of the structurally intact zona pellucida, and that this constraint should be removed in solubilized zonae. The fluorescent probe, Dapoxyl(TM) (2-aminoethyl)sulfonamide (DAES) allowed a test of this hypothesis in a population of sperm cells. It is a weak base that is non-fluorescent in aqueous solution, but which accumulates in the acidic acrosomal compartment due to the pH gradient with highly enhanced fluorescence; loss of the pH gradient leads to a decrease in fluorescence. The half-time for DAES fluorescence loss in a population of capacitated, acrosome-intact sperm in response to solubilized zona pellucida protein was 2.13 +/- 0.10 min (SEM, n = 9). The agreement between single cell and cell population kinetics validates the hypothesis of steric constraint in the structurally intact zona pellucida. The change in intracellular Ca(2+) concentration in response to solubilized zona pellucida, as monitored with fluo-3, was a rapid increase, followed by a decrease, with a half-time of 0.85 +/- 0.09 min (SEM, n = 6) to a steady state level higher than the initial level, indicating this Ca(2+) transient as the precursor reaction to onset of the zona-induced acrosome reaction. Copyright 2000 Wiley-Liss, Inc.

  14. A unique 2-sulfated {beta}-galactan from the egg jelly of the sea urchin Glyptocidaris crenularis: conformation flexibility versus induction of the sperm acrosome reaction.

    Castro, Michelle O; Pomin, Vitor H; Santos, Livia L; Vilela-Silva, Ana-Cristina E S; Hirohashi, Noritaka; Pol-Fachin, Laércio; Verli, Hugo; Mourão, Paulo A S


    Sulfated polysaccharides from the egg jelly of sea urchins act as species-specific inducers of the sperm acrosome reaction, which is a rare molecular mechanism of carbohydrate-induced signal-transduction event in animal cells. The sea urchin polysaccharides differ in monosaccharide composition (l-fucose or l-galactose), glycosylation, and sulfation sites, but they are always in the alpha-anomeric configuration. Herein, structural analysis of the polysaccharide from the sea urchin Glyptocidaris crenularis surprisingly revealed a unique sulfated beta-d-galactan composed by (3-beta-d-Galp-2(OSO(3))-1-->3-beta-d-Galp-1)(n) repeating units. Subsequently, we used the G. crenularis galactan to compare different 2-sulfated polysaccharides as inducers of the acrosome reaction using homologous and heterologous sperm. We also tested the effect of chemically over-sulfated galactans. Intriguingly, the anomeric configuration of the glycosidic linkage rather than the monosaccharide composition (galactose or fucose) is the preferential structural requirement for the effect of these polysaccharides on sea urchin fertilization. Nuclear magnetic resonance and molecular dynamics indicate that sulfated alpha-galactan or alpha-fucan have less dynamic structural behavior, exhibiting fewer conformational populations, with an almost exclusive conformational state with glycosidic dihedral angles Phi/Psi = -102 degrees /131 degrees . The preponderant conformer observed in the sulfated alpha-galactan or alpha-fucan is not observed among populations in the beta-form despite its more flexible structure in solution. Possibly, a proper spatial arrangement is required for interaction of the sea urchin-sulfated polysaccharides with the specific sperm receptor.

  15. Genome-wide association study implicates testis-sperm specific FKBP6 as a susceptibility locus for impaired acrosome reaction in stallions.

    Terje Raudsepp

    Full Text Available Impaired acrosomal reaction (IAR of sperm causes male subfertility in humans and animals. Despite compelling evidence about the genetic control over acrosome biogenesis and function, the genomics of IAR is as yet poorly understood, providing no molecular tools for diagnostics. Here we conducted Equine SNP50 Beadchip genotyping and GWAS using 7 IAR-affected and 37 control Thoroughbred stallions. A significant (PA and g.11040379C>A (p.166H>N in exon 4 that were significantly associated with the IAR phenotype both in the GWAS cohort (n = 44 and in a large multi-breed cohort of 265 horses. All IAR stallions were homozygous for the A-alleles, while this genotype was found only in 2% of controls. The equine FKBP6 was exclusively expressed in testis and sperm and had 5 different transcripts, of which 4 were novel. The expression of this gene in AC/AG heterozygous controls was monoallelic, and we observed a tendency for FKBP6 up-regulation in IAR stallions compared to controls. Because exon 4 SNPs had no effect on the protein structure, it is likely that FKBP6 relates to the IAR phenotype via regulatory or modifying functions. In conclusion, FKBP6 was considered a susceptibility gene of incomplete penetrance for IAR in stallions and a candidate gene for male subfertility in mammals. FKBP6 genotyping is recommended for the detection of IAR-susceptible individuals among potential breeding stallions. Successful use of sperm as a source of DNA and RNA propagates non-invasive sample procurement for fertility genomics in animals and humans.

  16. The Relationship between Some Ions and Acrosome Reactionof Human Sperm

    王春年; 谢文英; 徐胜; 王一飞


    The acrosome reaction of sperm was induced by calcium ionophore A 23187. The relationship between some ions and acrosome reaction by removing Na+ from the medium,or by adding antagonist of K+, TEA chloride, or antagonist of Ca++, verapamiI, or antagonist of Na+-h+-ATPase, acetyl strophanthidin is studied The results show that Na+,K+, Ca++ and Na+ pump are necessary for acrosome reaction of human sperm. The Ca++ might not enter the sperms through the channel of Ca++.

  17. The effects of ZAG on the acrosome reaction (AR) of human spermatozoa%锌-α2糖蛋白在人精子顶体反应过程中的作用

    郭毅; 刘悦; 王羽; 滕晓明


    Objective To explore the effects of ZAG(Zn-alpha2-glycoprotein) on the process of AR. Methods Indirect immunofluorescence and spermatozoa-ZP binding tests were used to analyze the effects of ZAG on human sperm acrosome reaction. Results Immunofluorescence staining revealed intensive immunoreactivity of ZAG in the acrosomal region was largely reduced in acrosome reacted spermatozoa, and human spermatozoa-ZP binding test indicated the spermatozoa’ s ability binding to ZP significantly decreased in spermatozoa treated with anti-ZAG antibody. Conclusion ZAG has significant effects on the acrosome reaction and the spermatozoa-ZP binding.%目的:初步探讨锌-α2糖蛋白(ZAG)在人精子顶体反应中的作用。方法采用ZAG抗体对人精子进行免疫荧光染色,激光共聚焦显微镜观察ZAG在顶体反应前后定位的变化,并通过精子透明带结合实验进一步证明ZAG在顶体反应中的作用。结果顶体反应后精子顶体头部的ZAG荧光明显下降甚至消失。精子经ZAG抗体处理后,其透明带结合能力显著下降。结论 ZAG在人精子顶体反应中发挥一定的作用,并影响人精子的透明带结合能力。本研究为探索ZAG在受精过程中的功能及分子作用机制奠定基础。

  18. In vitro induction of the acrosome reaction in bull sperm and the relationship to field fertility using low-dose inseminations

    Birck, A; Christensen, P; Labouriau, R


    . Furthermore, large-scale fertility trials using low-dose inseminations are pending. In the current study, the relationship between field fertility and the in vitro-induced AR was investigated using three ejaculates from each of 195 bulls, 156 Holstein and 39 Jersey bulls (Bos taurus), participating...... inseminations in 4721 herds and 208 artificial insemination (AI) technicians. Simultaneous detection of sperm viability and acrosomal status was achieved using a triple color flow cytometric technique. Sperm samples from the bulls displayed a wide range of ability to acrosome react in response to calcium...

  19. Relationship between seminal plasma zinc concentration and spermatozoa-zona pellucida binding and the ZP-induced acrosome reaction in subfertile men.

    Liu, De-Yi; Sie, Boon-Shih; Liu, Ming-Li; Agresta, Franca; Baker, H W Gordon


    The aim of this study was to determine the relationship between seminal zinc concentration and spermatozoa-zona pellucida (ZP) binding and the ZP-induced acrosome reaction (ZPIAR) in subfertile men. Semen analyses and seminal zinc concentration assessments were carried out according to the World Health Organization manual for 458 subfertile men. A spermatozoa-ZP interaction test was carried out by incubating 2 x 10(6) motile spermatozoa with a group of four unfertilized oocytes obtained from a clinical in vitro fertilization programme. After 2 h of incubation, the number of spermatozoa bound per ZP and the ZPIAR of ZP-bound spermatozoa were examined. The effect of adding 0.5 mmol L(-1) zinc to the media on the ZPIAR of spermatozoa from normozoospermic men was also tested in vitro. Seminal zinc concentration positively correlated with sperm count and duration of abstinence, but negatively correlated with semen volume. On analysis of data from all participants, both spermatozoa-ZP binding and the ZPIAR were significantly correlated with sperm motility and normal morphology, but not with seminal zinc concentration. However, in men with normozoospermic semen, the seminal zinc concentration was significantly higher in men with defective ZPIAR (or= 16%) (P zinc to the culture media had no effect on spermatozoa-ZP binding, but significantly reduced the ZPIAR in vitro (P zinc concentration is correlated with sperm count and the duration of abstinence in subfertile men. In men with normozoospermic semen, high seminal zinc concentration may have an adverse effect on the ZPIAR.

  20. Protein tyrosine phosphorylation, hyperactivation and progesterone-induced acrosome reaction are enhanced in IVF media: an effect that is not associated with an increase in protein kinase A activation.

    Moseley, F L C; Jha, K N; Björndahl, Lars; Brewis, I A; Publicover, S J; Barratt, C L R; Lefièvre, L


    Sperm capacitation is a prerequisite for successful in vitro fertilization (IVF) and therefore a focus of sperm preparation in IVF laboratories. The technology of IVF is, therefore, potentially valuable in advancing our understanding of the molecular processes that occur during sperm capacitation. We have investigated sperm capacitation induced by a commercial IVF medium compared to that occurring in standard capacitating medium (CM) typically used in a nonclinical setting. Percoll-washed spermatozoa were resuspended in Cook Sydney IVF medium, Cook Sydney IVF sperm buffer, Earle's balanced salt medium (capacitating medium) or a modified Earle's balanced salt medium [non-capacitating medium (NCM)] for up to 120 min at 37 degrees C and, if applicable, in the presence of 5% CO2 in air. Sperm protein kinase A (PKA) activity, PKA-dependent serine/threonine phosphorylation, tyrosine phosphorylation, hyperactivation and progesterone-induced acrosome reaction were evaluated. IVF medium was shown to accelerate sperm capacitation (compared with capacitating medium) as determined by tyrosine phosphorylation, sperm hyperactivation and progesterone-induced acrosome reaction. This effect was not associated with enhanced activation of PKA or increased levels of serine/threonine phosphorylation. In contrast, IVF sperm buffer (used for sperm preparation) did not stimulate sperm capacitation when incubated for up to 90 min. We have shown that different capacitating media vary strikingly in their efficacy and that this difference reflects activation of a pathway other than the well-characterized activation of soluble adenylyl cyclase/cAMP/PKA.

  1. Identification of bovine sperm acrosomal proteins that interact with a 32-kDa acrosomal matrix protein.

    Nagdas, Subir K; Smith, Linda; Medina-Ortiz, Ilza; Hernandez-Encarnacion, Luisa; Raychoudhury, Samir


    reaction, whereas the IZUMO1 and lactadherin polypeptides remain associated to the particulate fraction. Almost entire population of bovine sperm IZUMO1 relocates to the equatorial segment during the LPC-induced acrosome reaction. We propose that the interaction of OMC32 matrix polypeptide with detergent-soluble acrosomal proteins regulates the release of hydrolases/other acrosomal protein(s) during the acrosome reaction.

  2. The acrosomal matrix from guinea pig sperm contains structural proteins, suggesting the presence of an actin skeleton.

    Zepeda-Bastida, Armando; Chiquete-Felix, Natalia; Uribe-Carvajal, Salvador; Mujica, Adela


    The mammalian sperm acrosome contains a large number of hydrolytic enzymes. When the acrosomal reaction and fertilization occur, these enzymes are released in an orderly fashion, suggesting that the acrosomal matrix is highly organized. It was decided to determine the identity of the structural scaffold underlying the organization of the acrosome. In permeabilized acrosomes and in the Triton X-100-extracted acrosomal matrices from guinea pig sperm, we used indirect immunofluorescence, immunogold labeling, and Western blotting to identify F-actin, spectrin, myosin, calmodulin, and gelsolin. These proteins were detected in the acrosomal matrix for the first time. In noncapacitated, intact spermatozoa the addition of the F-actin monomerizing agent cytochalasin D resulted in loss of the acrosome, suggesting that F-actin is needed to preserve an intact acrosome. Our results suggest that the acrosomal architecture is supported by a dynamic F-actin skeleton, which probably regulates the differential rate of release of the acrosomal enzymes during acrosomal reaction and fertilization.

  3. Inhibition of mouse acrosome reaction and sperm-zona pellucida binding by anti-human sperm membrane protein 1 antibody%抗人精子膜蛋白抗体1对小鼠精子顶体反应和精子-透明带结合的抑制作用

    G.Y.Cheng; J.L.Shi; M.Wang; Y.Q.Hu; C.M.Liu; Y.F.Wang; C.Xu


    Aim:To investigate the possible functions of human sperm membrane protein (hSMP-1) in the process of fertilization.Methods: A 576-bp cDNA fragment of HSD-1 gene coding for the extracellular domain of hSMP-1 was cloned and expressed. The localization of this protein on human and mouse sperm was determined by indirect immunofluorescent staining by using anti-recombinant hSMP-1 (anti-rhSMP-1) antibodies. Sperm acrosome reaction and spermzona pellucida (ZP) binding assay were carried out in 10-week-old BALB/c mice. Results: Recombinant hSMP-1 was successfully cloned and expressed. The expression of the native protein was limited on the acrosome of human and mouse sperm. Treatment of anti-rhSMP-1 antibodies significantly decreased the average number of sperms bound to each egg. Meanwhile, the percentage of acrosome reaction was decreased in comparison to pre-immune control after treatment with anti-rhSMP-1 (P < 0.05). Conclusion: The results suggest that anti-rhSMP-1 antibody inhibited mouse acrosome reaction and sperm-ZP binding.

  4. The acrosome of eutherian mammals.

    Fléchon, Jacques-Edmond


    The acrosome is not just a bag of enzymes, most of which, if not all, are singly non-essential for sperm-oocyte interaction. The Golgi-derived acrosomal cap reveals some extraordinary development and structure particularities. The acrosome of eutherian spermatozoa basically consists of two parts, the anterior and equatorial segments; the present review is devoted to the former, the initial actor in fertilization. Its occasional fanciful morphological changes during epididymal maturation are analyzed, together with its heterogeneous contents: enzymes, zona binding proteins, structural proteins (matrix) and yet to be chemically characterized crystalloids. The plasma and acrosomal membranes present stabilized ordered domains, whereas glycoprotein-free areas appear during capacitation and before fusion. Exocytosis, induced by the cumulus oophorus and/or the zona pellucida, may generally start proximally and progress anteriorly, resulting in the detachment of a hybrid membrane shroud, whose entity is probably maintained by the bound matrix. Immediately released soluble enzymes must be active during the first interactions of the gametes, whereas other lysins, bound to the matrix or stored as proenzymes, are only progressively released. Zona binding is probably achieved via the shroud and/or the IAM (depending on species). Penetration along an incurved slit through the stratified zona is allowed by the rigid and denuded head tip and flagellar hyperactivity, and assisted by the local proteolytic activity of proteasomes bound to the IAM, the unique essential zona lysin system.

  5. Comparative ultracytochemical study of the acrosome in four different Veneroida species from the Turkish coast.

    Erkan, M; Sousa, M; Baldaia, L


    Cytoplasmic acidic phosphoproteins and complex polysaccharides were stained with ammoniacal silver nitrate-formalin and phosphotungstic acid-chromic acid, respectively. In Cerastoderma glaucum (Cardiacea), acrosomal vesicle contents are differentiated into an apical intermediate-dense component and a basal dense region. PTA stained the apical component and silver stained the basal region and the apex of the acrosome. In Spisula subtruncata (Mactracea) the acrosome showed a PTA-stained apical component and a silver-positive basal dense region. In the Veneracea, Chamelea gallina and Pitar rudis show a tripartite acrosomal vesicle, with apical light, outer dense and inner intermediate-dense regions. In both species, the apical and inner components were stained by PTA, whereas silver stained all regions of the acrosomal vesicle in C. gallina and the apical and outer regions in P. rudis. In midpiece, only C. glaucum showed a positive silver reaction at the centriolar fossa.

  6. Effect of GABA on sperm acrosome reation in antisperm antibody positive patients

    BianSL; ZhanW


    Objective:To investigate the effect of gamma-aminobutyric acid(GABA) on the rate of sperm acrosome reaction both in normal and antisperm antibody (AsAb) porsitive men.Methods:the sperm acrosome reaction was tested with triplestain technique in two groups of 18 men each.Results:(1)GABA increased the rate of sperm acrosome reaction both in normal and AsAb positive subjects(P<0.01);(2) GABA increased the Na+-K+-ATPase activity of sperm(P<0.01);(3)GABA increased the Ca2+-ATPase activity of sperm (P<0.05);(4)GABA decreased the production of MDA and oxygen free radicals of sperm.conclusion:GABA could regulate the rate of sperm acrosome reaction.

  7. Isolation of a calcium-binding protein of the acrosomal membrane of bovine spermatozoa

    Nagdas, Subir K.; Buchanan, Teresa; McCaskill, Shaina; Mackey, Jared; Alvarez, George E.; Raychoudhury, Samir


    The mammalian sperm acrosome reaction is a calcium-dependent exocytotic event characterized by extensive fusion between the plasma and the outer acrosomal membrane. The mechanisms by which elevation of cytosolic calcium initiates the membrane fusion process are not understood and the present study was undertaken to identify calcium-binding proteins in the acrosomal membrane (AM) of bovine spermatozoa. Sperm heads, purified from sonicated spermatozoa, were used to isolate an acrosomal membrane-enriched fraction on Percoll density gradients. Using SDS-PAGE and a 45Ca2+-blot overlay assay, calcium-binding proteins of 64, 45, 43, and 39 kDa were identified in the AM enriched fraction. Phase separation analysis with Triton X-114 identified the 64 kDa polypeptide as an integral membrane protein. The 64 kDa polypeptide was purified and utilized to prepare a polyclonal antiserum. Both light and electron microscopic immunocytochemistry demonstrated that the protein was distributed throughout all domains of the acrosomal membrane. These results identify a 64 kDa calcium-binding integral membrane protein of the mammalian acrosome. Its potential function in calcium-dependent membrane fusion events of the acrosome reaction and in fertilization is discussed. PMID:23376657

  8. Identification and Characterization of a Bovine Sperm Acrosomal Matrix Protein and its Mechanism of Interaction with Acrosomal Hydrolases

    Nagdas, Subir K; Smith, Linda; Mcnamara, Allen; Hernandez–Encarnacion, Luisa; Medina-Ortiz, Ilza


    Fertilization, the union of male and female gametes to create offspring, is an intricate biological process dependent upon several biochemical and physiological events. Our understanding of the functions of protein constituents of the outer acrosomal membrane-associated matrix complex (OMC) is limited. A highly purified OMC fraction isolated from bovine cauda sperm heads is comprised of 54, 50, 45, and 38–19kDa polypeptides. The objective of this study is to identify and to characterize the 45kDa (OMC45) polypeptide and to define its role in binding acrosomal hydrolases and to examine the fate of OMC45 polypeptide during the acrosome reaction. We isolated OMC45 polypeptide from the high-pH insoluble fraction of OMC. Proteomic analysis of OMC45 by MALDI–TOF–TOF yielded 8 peptides that matched the NCBI database sequence of Tektin 3 (TEKT3). Triton X–100–permeabilized cauda sperm exhibited intense staining of the acrosomal segment with anti–OMC45 and anti–TEKT3. The OMC45 polypeptide was solubilized by RIPA (radio-immunoprecipitation assay) buffer extraction. The solubilized fraction was subjected to immunoprecipitation analysis. The OMC45 polypeptide was recovered in the anti–OMC45 immunoprecipitation pellet. An identical blot stained with anti–TEKT3 exhibited the presence of TEKT3 polypeptide in the anti–OMC45 pellet. Our immunofluorescence and biochemical studies confirm the proteomics identification of OMC45 polypeptide; that it exhibits a sequence similarity to TEKT3. OMC45 glycoprotein possesses both N–linked and O–linked oligosaccharides. Deglycosylated OMC45 revealed a significant reduction in both acrosin and N–acetylglucosaminidase (NAGA) binding in comparison with acrosin and NAGA binding to a native OMC45 polypeptide, demonstrating the important role of oligosaccharides in hydrolase binding. OMC45 polypeptide is not released during the acrosome reaction but remains in the particulate cell subfraction, associated with the hybrid

  9. Involvement of Complexin 2 in Docking, Locking and Unlocking of Different SNARE Complexes during Sperm Capacitation and Induced Acrosomal Exocytosis.

    Tsai, P.S.; Brewis, I.A.; van Maaren, J.; Gadella, B.M.


    Acrosomal exocytosis (AE) is an intracellular multipoint fusion reaction of the sperm plasma membrane (PM) with the outer acrosomal membrane (OAM). This unique exocytotic event enables the penetration of the sperm through the zona pellucida of the oocyte. We previously observed a stable docking of O

  10. Visible Light Mediated Photoredox Catalytic Arylation Reactions.

    Ghosh, Indrajit; Marzo, Leyre; Das, Amrita; Shaikh, Rizwan; König, Burkhard


    Introducing aryl- and heteroaryl moieties into molecular scaffolds are often key steps in the syntheses of natural products, drugs, or functional materials. A variety of cross-coupling methods have been well established, mainly using transition metal mediated reactions between prefunctionalized substrates and arenes or C-H arylations with functionalization in only one coupling partner. Although highly developed, one drawback of the established sp2-sp2 arylations is the required transition metal catalyst, often in combination with specific ligands and additives. Therefore, photoredox mediated arylation methods have been developed as alternative over the past decade. We begin our survey with visible light photo-Meerwein arylation reactions, which allow C-H arylation of heteroarenes, enones, alkenes, and alkynes with organic dyes, such as eosin Y, as the photocatalyst. A good number of examples from different groups illustrate the broad application of the reaction in synthetic transformations. While initially only photo-Meerwein arylation-elimination processes were reported, the reaction was later extended to photo-Meerwein arylation-addition reactions giving access to the photoinduced three component synthesis of amides and esters from alkenes, aryl diazonium salts, nitriles or formamides, respectively. Other substrates with redox-active leaving groups have been explored in photocatalyzed arylation reactions, such as diaryliodonium and triarylsulfonium salts, and arylsulfonyl chlorides. We discus some examples with their scope and limitations. The scope of arylation reagents for photoredox reactions was extended to aryl halides. The challenge here is the extremely negative reduction potential of aryl halides in the initial electron transfer step compared to, e.g., aryl diazonium or diaryliodonium salts. In order to reach reduction potentials over -2.0 V vs SCE two consecutive photoinduced electron transfer steps were used. The intermediary formed colored radical

  11. Participación de enzimas translocasas en la reacción acrosomal del espermatozoide de conejo

    Mayren-Mendoza, Félix de Jesús


    Full Text Available ResumenEste estudio se realizó con la finalidad de evaluar la participación de enzimas translocadoras de fosfolípidos en el proceso de reacción acrosomal, en espermatozoides de conejo obtenidos de la región caudal del epidídimo, utilizando la progesterona como inductor de reacción acrosomal y NEtilmaleimida como inhibidor de translocasas.SummaryThis study was conducted in order to evaluate the participation of translocating enzymes of phospholipids in the reaction process acrosomal in rabbit sperm obtained from the caudal region of epididymis, using progesterone as inducer of acrosome reaction and N-ethylmaleimide as an inhibitor of translocase.

  12. Cycle of the seminiferous epithelium of the bat Molossus molossus, characterized by tubular morphology and acrosomal development

    Danielle Barbosa Morais; Tarcizio Antnio Rgo de Paula; Karine Moura de Freitas; Srgio Luis Pinto da Matta


    Objective:To describe the seminiferous epithelium cycle (SEC) by tubular morphology method, and the acrosomal development of individualizing spermatids, and to explore the distinction of the stages between two generations of spermatids. Methods: Testicular fragments were fixed in Karnovsky, embedded in glycol methacrylate and examined under light microscopy and transmission electron microscopy. Sections in 3 µm thickness were stained with toluidine blue for the characterization of the stages of the SEC by the tubular morphology method, or submitted to the PAS reaction for the visualization of the acrosomal formation. Additional details on the acrosomal formation were observed under transmission electron microscopy. Results:Through the eight stages described by tubular morphology method, 10 steps of acrosomal formation were observed in the spermatid development, called acrosomal steps. As the spermatids were produced in stage V of the tubular morphology method, it was at this stage from which began the steps of acrosomal development. Conclusions:We propose association of the acrosomal steps for the first time, with the different stages by tubular morphology method. This method presents an alternative to the existent methods, allowing interspecific comparisons of the SEC, not only among different species of bats, but also among the other mammals.

  13. Normative Mediation of Reactions to Crowding

    Karlin, Robert A.; And Others


    This study manipulated norms governing interaction levels in crowded groups of women. Results indicated norms influenced reactions to crowding as predicted. Women reacted most positively when interaction levels were high and most negatively when interaction levels were low. (Author)

  14. Mechanochemical Lignin-Mediated Strecker Reaction

    Saumya Dabral


    Full Text Available A mechanochemical Strecker reaction involving a wide range of aldehydes (aromatic, heteroaromatic and aliphatic, amines, and KCN afforded a library of α-aminonitriles upon mechanical activation. This multicomponent process was efficiently activated by lignocellulosic biomass as additives. Particularly, commercially available Kraft lignin was found to be the best activator for the addition of cyanide to the in situ formed imines. A comparative study of the 31P-NMR (Nuclear Magnetic Resonance along with IR (Infrared data analysis for the Kraft lignin and methylated Kraft lignin samples ascertained the importance of the free hydroxyl groups in the activation of the mechanochemical reaction. The solvent-free mechanochemical Strecker reaction was then coupled with a lactamization process leading to the formation of the N-benzylphthalimide (5a and the isoindolinone derivative 6a.

  15. Efficient copper-mediated reactions of nitrenes derived from sulfonimidamides.

    Leca, Dominique; Toussaint, Aurélie; Mareau, Camille; Fensterbank, Louis; Lacôte, Emmanuel; Malacria, Max


    [reaction: see text] Sulfonimidamides lead efficiently to nitrenes and have been converted to sulfimides, sulfoximines, and aziridines in good yields, through a copper-mediated multicomponent reaction. The stereogenic sulfur atom and the trivalent nitrogen atom present in the molecules open the way to asymmetric synthesis, whose first results are presented.

  16. Evaluation on Sperm Acrosome Integrity of Infertile Men with Varicocele

    P.Tzvetkova; Wei-jie ZHU; Jing LI; D.Tzvetkov


    Objective To determine the sperm acrosome integrity of samples from infertile men with varicocele.Methods Forty-nine infertile men with varicocele were divided into three groups according to the grade of varicocele. Group A (grade Ⅰ), B (grade Ⅱ), and C (grade Ⅲ) consisted of 15, 18, and 16 cases, respectively. Besides, 15 semen samples from normospermic donors were used as the control. The acrosome integrity of sperm was examined with fluorescein-labeled Pisum sativum agglutinin. Acrosomal ultrastructure was observed with transmission electron microscopy.Results In three varicocele groups, most samples had high sperm abnormal morphology rates. There were significant differences in acrosome integrity rates between each varicocele group and the control (P<0.01). Group C had the lowest acrosome integrity rate among the three groups. Ultrastructural observation showed that acrosome malformations revealed acrosomal membranes defects, swelling, hypoplasia, and dissolution of the matrix.Conclusions Infertile men with varicocele had low level of acrosome integrity. Severe varicocele for infertile men might be associated with severe acrosomal defects. Evaluating sperm acrosome should aid the understanding of the sperm structural state and benefit the treatment for infertile men.

  17. Evidence that nitric oxide synthase is involved in progesterone-induced acrosomal exocytosis in mouse spermatozoa.

    Herrero, M B; Viggiano, J M; Pérez Martínez, S; de Gimeno, M F


    In a recent work, we detected nitric oxide synthase (NO synthase) in the acrosome and tail of mouse and human spermatozoa by an immunofluorescence technique. Also, NO-synthase inhibitors added during sperm capacitation in vitro reduced the percentage of oocytes fertilized in vitro, suggesting a role for NO synthase in sperm function. Therefore, in the present study the effect of three NO-synthase inhibitors, NG-nitro-L-arginine methyl ester (L-NAME), NG-nitro-D-arginine methyl ester (D-NAME) and L-NG-nitro-arginine (NO2-arg), and of a nitric oxide donor, spermine-NONOate, on the progesterone-induced acrosome reaction of mouse sperm was examined. NO-synthase inhibitors were added at 0, 60 or 90 min during capacitation; at 120 min, mouse epididymal spermatozoa were exposed to 15 microM progesterone for another 15 min. In another set of experiments, different concentrations of spermine-NONOate were added to capacitated spermatozoa for 15 min; in these experiments, progesterone was not included. NO2-arg and L-NAME blocked progesterone-induced exocytosis regardless of the time at which these inhibitors were added. Moreover, D-NAME did not inhibit exocytosis. In contrast, spermine-NONOate stimulated the acrosomal exocytosis in vitro directly. These results provide evidence that mouse sperm NO synthase participates in the progesterone-induced acrosome reaction in vitro and that nitric oxide induces this event.

  18. LVQ acrosome integrity assessment of boar sperm cells

    Petkov, Nicolai; Alegre, Enrique; Biehl, Michael; Sánchez, Lidia; Tavares, JMRS; Jorge, RMN


    We consider images of boar spermatozoa obtained with an optical phase-contrast microscope. Our goal is to automatically classify single sperm cells as acrosome-intact (class 1) or acrosome-reacted (class 2). Such classification is important for the estimation of the fertilization potential of a sper

  19. LVQ acrosome integrity assessment of boar sperm cells

    Petkov, Nicolai; Alegre, Enrique; Biehl, Michael; Sánchez, Lidia


    We consider images of boar spermatozoa obtained with an optical phase-contrast microscope. Our goal is to automatically classify single sperm cells as acrosome-intact (class 1) or acrosome-reacted (class 2). Such classification is important for the estimation of the fertilization potential of a sper

  20. Effects of pentoxifylline treatment before freezing on motility, viability and acrosome status of poor quality human spermatozoa cryopreserved by the liquid nitrogen vapor method

    S.C. Esteves


    Full Text Available The objective of the present study was to investigate the effects of the direct addition of pentoxifylline (PF to the ejaculates of men with poor sperm quality before freezing on post-thaw sperm motility, viability, acrosome integrity, and agonist-induced acrosome reaction. Semen specimens from 16 infertile men with impaired sperm count and motility (oligoasthenozoospermia were divided into two equal aliquots: one received no treatment (control while the other was incubated with 5 mM PF (treated. Both aliquots were cryopreserved by the liquid nitrogen vapor method. Motility was assessed according to WHO criteria. Acrosome integrity and spontaneous and calcium ionophore-induced acrosome reactions were assessed with fluorescein isothiocyanate-conjugated peanut agglutinin combined with a supra-vital dye (Hoechst-33258. Cryopreservation impaired sperm motility (percentage reduction: 87.4 (interquartile range, IQ: 70.3-92.9 vs 89.1 (IQ: 72.7-96.0%, viability (25.9 (IQ: 22.2-29.7 vs 25.6 (IQ: 19.7-40.3% and acrosome integrity (18.9 (IQ: 5.4-38.9 vs 26.8 (IQ: 0.0-45.2% to the same extent in both treated and control aliquots. However, PF treatment before freezing improved the acrosome reaction to ionophore challenge test scores in cryopreserved spermatozoa (9.7 (IQ: 6.6-19.7 vs 4.8 (IQ: 0.5-6.8%; P = 0.002. These data show that pre-freeze treatment of poor quality human sperm with pentoxifylline did not improve post-thaw motility or viability nor did it prevent acrosomal loss during the freeze-thaw process. However, PF, as used, improved the ability of thawed spermatozoa to undergo the acrosome reaction in response to calcium ionophore. The present data indicate that treatment of poor quality human sperm with PF may enhance post-thaw sperm fertilizing ability.

  1. Reaction mechanisms of ruthenium tetroxide mediated oxidations of organic compounds

    Froehaug, Astrid Elisabeth


    This thesis reports a study of the mechanism of ruthenium tetroxide mediated oxidations of saturated hydrocarbons, ethers, alkenes and alcohols. Several methods were used. The RuO{sub 4}-mediated oxidations of adamantane and cis-decalin were studied in CCl{sub 4}-CH{sub 3}CN-H{sub 2}O and in acetone-water. The rate of reaction was found to be moderately influenced by the polarity of the solvent. Solvent properties other than the polarity were also found to influence the reaction rates. From the oxidations of adamantane and adamantane-1,3,5,7-d{sub 4} two primary kinetic deuterium isotope effects were found. These were comparable with the deuterium isotope effects found for the analogous oxidations of cis-decalin and cis-decalin-d{sub 18}. The results seem to exclude both a one step hydride abstraction reaction mechanism and a one step concerted mechanism, as well as a scheme where two such mechanisms compete. The observations may be explained by a two step reaction mechanism consisting of a pre-equilibrium with formation of a substrate-RuO{sub 4} complex followed by a concerted rate determining reaction. The RuO{sub 4}-mediated oxidation of ethers was of kinetic second order with a small enthalpy of activation and a large negative entropy of activation. Oxidation of cyclopropylmethyl methyl ether gave methyl cyclopropanecarboxylate, no rearranged products were observed. On RuO{sub 4} oxidations in CCl{sub 4} with NaIO{sub 4} as stoichiometric oxidant, no chlorinated products were observed. Several observations not in agreement with a hydride or a hydrogen abstraction mechanism may be explained by assuming that the reaction proceeds by either a concerted reaction or by a reversible oxidative addition of the ether to RuO{sub 4} followed by a slow concerted step. 228 refs., 9 figs., 27 tabs.

  2. A Note on the Kinetics of Diffusion-mediated Reactions

    Naqvi, K Razi


    The prevalent scheme of a diffusion-mediated bimolecular reaction $A+B\\rightarrow P$ is an adaptation of that proposed by Briggs and Haldane for enzyme action [{\\em Biochem J.\\/}, 19:338--339, 1925]. The purpose of this Note is to explain, {\\em by using an argument involving no mathematics\\/}, why the breakup of the encounter complex cannot be described, except in special circumstances, in terms of a first-order process $\\{AB\\}\\rightarrow A+B$. Briefly, such a description neglects the occurrence of re-encounters, which lie at the heart of Noyes's theory of diffusion-mediated reactions. The relation $k=\\alpha k_{\\mbox{\\scriptsize e}}$ becomes valid only when $\\alpha$ (the reaction probability per encounter) is very much smaller than unity (activation-controlled reactions), or when $\\beta$ (the re-encounter probability) is negligible (as happens in a gas-phase reaction). References to some works (by the author and his collaborators) which propound the correct approach for finding $k$ are also supplied.

  3. Green spermatozoa illuminate a 30-year-old model:sperm-egg adhesion involves intra-acrosomal proteins

    Steve Tardif


    @@ Fertilisation in mammals involves many synchronized steps including spermegg adhesion.Prior to sperm-oolemma fusion,spermatozoa need to undergo the acrosome reaction (AR) or exocytosis.The universal belief,for many years,has been that the AR was initiated upon binding to the zona pellucida (ZP).As such acrosomal proteins were not thought to be involved in the primary contact with the ZP.These proteins were only suggested to be biologically relevant once the sperm were attached to the ZP and during subsequent events.However,recent data in the mouse have unequivocally demonstrated that spermatozoa can begin exocytosis before contact with ZP.1 It is a remarkable finding as not only will the interpretation of the interaction between sperm and cumulus cells need to be revised,but the processes of capacitation,vesiculation and exposure of acrosomal content need reexamination.

  4. Statistical properties of multistep enzyme-mediated reactions

    Nemenman, Ilya [Los Alamos National Laboratory; Sinitsyn, Nikolai A [Los Alamos National Laboratory; De Ronde, Wiet H [AMOLF; Daniels, Bryan C [CORNELL; Mugler, Andrew [COLUMBIA


    Enzyme-mediated reactions may proceed through multiple intermediate conformational states before creating a final product molecule, and one often wishes to identify such intermediate structures from observations of the product creation. In this paper, we address this problem by solving the chemical master equations for various enzymatic reactions. We devise a perturbation theory analogous to that used in quantum mechanics that allows us to determine the first () and the second (variance) cumulants of the distribution of created product molecules as a function of the substrate concentration and the kinetic rates of the intermediate processes. The mean product flux V=d/dt (or 'dose-response' curve) and the Fano factor F=variance/ are both realistically measurable quantities, and while the mean flux can often appear the same for different reaction types, the Fano factor can be quite different. This suggests both qualitative and quantitative ways to discriminate between different reaction schemes, and we explore this possibility in the context of four sample multistep enzymatic reactions. We argue that measuring both the mean flux and the Fano factor can not only discriminate between reaction types, but can also provide some detailed information about the internal, unobserved kinetic rates, and this can be done without measuring single-molecule transition events.

  5. Association between calcium ionophore A23187 induced acrosome reaction rate, total acrosin activity and semen analysis, the outcome of in vitro fertilization%钙离子载体A23187诱发的精子顶体反应率、顶体酶总活性与精液参数及体外受精结局的关系研究

    郭小桥; 余波澜; 周华; 司沙沙; 曹定娅; 刘见桥; 孙筱放


    Objective To investigate the association between the calcium ionophore A23187 induced sperm acrosome reaction rate, total acrosin activity and semen parameters and the IVF outcome, and to compare the predictive value for the male fertility and the outcome of IVF between calcium ionophore A23187 induced sperm acrosome reaction rate and sperm total acrosoin activity. Methods Sperm acrosome reaction was induced by calcium ionophore A23187,while sperm acrosin activity was determined by the modified Kennedy method. In this study, 150 cycles of IVF-ET were included, which were divided into Normal semen Group (85 cycles), Teratospermia Group (44 cycles), Asthenozoospermia Group (6 cycles). Compare the association between the calcium ionophore A23187 induced sperm acrosome reaction rate, total acrosin activity and normal morphology sperm percentage, concentration, activity in the 150 cycles and subgroups. Analyze the difference of the sperm acrosome reaction rate and total acrosin activity in Pregnancy Group and Non-pregnancy Group. Use the Receiver Operating Characteristic curve to make out the threshold of the sperm acrosome reaction rate and total acrosin activity for predicting the IVF pregnancy outcomes. Results In this 150 samples, there are no statistically significant differences between sperm acrosome reaction rate and sperm concentration, progressive velocity rate, the percentage of normal sperm morphology, fertility rate, and their related coefficient are respectively as follow:0.120, 0.018, 0.084, 0.054(P>0.05). But the negative correlation is statistically significant different between sperm acrosome reaction rate and teratozoospermia index(r=-0.183, P=0.025). There are significant correlations between sperm acrosin activity and sperm concentration(r=0.172, P0.05) and fertility rate(r=0.039, P>0.05). There are no statistically significant differences between sperm acrosome rate and fertility rate in Normal semen Group(r=-0.039, P>0.05), Teratospermia Group

  6. Modern human sperm freezing: Effect on DNA, chromatin and acrosome integrity.

    Rahiminia, Tahereh; Hosseini, Akram; Anvari, Morteza; Ghasemi-Esmailabad, Saeed; Talebi, Ali Reza


    Presence of vitrification method in sperm freezing and the introduction of solid surface vitrification beside rapid freezing in vapour, opens an easy and safe way to help infertility centres. While the effects of cryopreservation on motility, morphology and viability of sperm are documented, the question of the probable alteration of sperm DNA, chromatin and acrosome integrity after freezing and thawing procedures in different methods is still controversial. Normal sample were collected according to WHO strict criteria. Sperm suspensions were mixed 1:1 with 0.5 M sucrose and divided into four equal aliquots for freezing: fresh, nitrogen direct immersion vitrification (Vit), solid surface vitrification (SSV) and in vapour (Vapour). Sperm suspensions were transferred into a 0.25 ml sterile plastic. Then straw was inserted inside the 0.5 ml straw. For thawing, the straws were immersed in a 42 °C water bath. Beside the sperm parameters, we assessed the acrosome reaction by double staining, chromatin integrity by toluidine blue (Tb) and chromomycin A3 (CMA3) and DNA integrity by terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) respectively. In progressive motility, the highest rate occurred in Vit (39.9 ± 13.3). Moreover, the lowest rate of immotile sperm was in Vit (32.7 ± 16.3). In normal morphology, the group Vit was similar to the fresh, while SSV and Vapour were significantly different from the fresh. The percentage of acrosome-reacted sperms was more in Vit (81.3 ± 10.2) than the fresh group. TUNEL+ results showed that DNA fragmentation was significantly increased in Vit (p-value = 0.025). While in SSV and Vapour results were comparable to fresh. There was a significant correlation between TUNEL+ and normal morphology, TB, CMA3 and presence of intact acrosome. Sperm in Vapour was healthier in terms of DNA, chromatin and acrosome integrity. In contrast of higher motility and normal morphology; DNA, chromatin and acrosome

  7. Dynamics of SNARE assembly and disassembly during sperm acrosomal exocytosis.

    Gerardo A De Blas


    Full Text Available The dynamics of SNARE assembly and disassembly during membrane recognition and fusion is a central issue in intracellular trafficking and regulated secretion. Exocytosis of sperm's single vesicle--the acrosome--is a synchronized, all-or-nothing process that happens only once in the life of the cell and depends on activation of both the GTP-binding protein Rab3 and of neurotoxin-sensitive SNAREs. These characteristics make acrosomal exocytosis a unique mammalian model for the study of the different phases of the membrane fusion cascade. By using a functional assay and immunofluorescence techniques in combination with neurotoxins and a photosensitive Ca2+ chelator we show that, in unactivated sperm, SNAREs are locked in heterotrimeric cis complexes. Upon Ca2+ entry into the cytoplasm, Rab3 is activated and triggers NSF/alpha-SNAP-dependent disassembly of cis SNARE complexes. Monomeric SNAREs in the plasma membrane and the outer acrosomal membrane are then free to reassemble in loose trans complexes that are resistant to NSF/alpha-SNAP and differentially sensitive to cleavage by two vesicle-associated membrane protein (VAMP-specific neurotoxins. Ca2+ must be released from inside the acrosome to trigger the final steps of membrane fusion that require fully assembled trans SNARE complexes and synaptotagmin. Our results indicate that the unidirectional and sequential disassembly and assembly of SNARE complexes drive acrosomal exocytosis.

  8. Peritoneal fluid modulates the sperm acrosomal exocytosis induced by N-acetylglucosaminyl neoglycoprotein

    E.P. Passos


    Full Text Available The effect of peritoneal fluid (PF on the human sperm acrosome reaction (AR was tested. Sperm was pre-incubated with PF and the AR was induced by calcium ionophore A23187 and a neoglycoprotein bearing N-acetylglycosamine residues (NGP. The AR induced by calcium ionophore was inhibited 40% by PF from controls (PFc and 50% by PF from the endometriosis (PFe group, but not by PF from infertile patients without endometriosis (PFi. No significant differences were found in the spontaneous AR. When the AR was induced by NGP, pre-incubation with PFc reduced (60% the percentage of AR, while PFe and PFi caused no significant differences. The average rates of acrosome reactions obtained in control, NGP- and ionophore-treated sperm showed that NGP-induced exocytosis differed significantly between the PFc (11% and PFe/PFi groups (17%, and the ionophore-induced AR was higher for PFi (33% than PFc/PFe (25%. The incidence of the NGP-induced AR was reduced in the first hour of pre-incubation with PFc and remained nearly constant throughout 4 h of incubation. The present data indicate that PF possesses a protective factor which prevents premature AR.

  9. Nanovid microscopy for assessing sperm membrane changes induced by in vitro capacitating and acrosomal reacting procedures.

    Degelos, S D; Wilson, M P; Chandler, J E


    This study was to verify the usefulness of Nanovid microscopy techniques for evaluating induced modifications in bovine spermatozoal membranes. Frozen thawed bovine sperm were labeled with 20-nm colloidal gold particles bound to concanavalin A (ConA) or heparin ligands. Sperm membrane changes were induced in vitro by capacitating and acrosome-reacting procedures. Capacitation was induced by incubation with 10 micrograms/ml of heparin for 4 hours at 37 degrees C, 5% CO2, and high humidity. Membrane changes associated with the acrosome reaction were induced by addition of lysophosphatidylcholine (100 micrograms/ml) and incubation for 15 minutes at 37 degrees C, 5% CO2, and high humidity. Gray intensity (black = 0; white = 255) of sperm (ONCELL) and background (OFFCELL) were evaluated with computer-enhanced videomicroscopy with either differential interference contrast (DIC) or Nanovid optics. A high gold concentration on a membrane region produced blacker video pictures with Nanovid microscopy. Gray intensity of video pictures of a region with little or no gold would have a gray intensity equal to or greater than that of the background, that is, toward white. Weighted least squares methods were used to analyze ONCELL data using OFFCELL as a covariate. In experiment 1, ONCELL intensities of cells labeled with ConA-gold complex were lower than those labeled with heparin-gold at the same treatment level. In experiment 2, ONCELL intensity decreased as the concentration of heparin-gold increased from 0 to 0.041 microgram/microliter heparin. ONCELL intensity significantly decreased after sperm were treated with the highest heparin-gold level and acrosome reacted.(ABSTRACT TRUNCATED AT 250 WORDS)

  10. Epac, Rap and Rab3 act in concert to mobilize calcium from sperm's acrosome during exocytosis.

    Ruete, María C; Lucchesi, Ornella; Bustos, Matías A; Tomes, Claudia N


    Exocytosis of sperm's single secretory granule or acrosome (acrosome reaction, AR) is a highly regulated event essential for fertilization. The AR begins with an influx of calcium from the extracellular milieu and continues with the synthesis of cAMP and the activation of its target Epac. The cascade bifurcates into a Rab3-GTP-driven limb that assembles the fusion machinery and a Rap-GTP-driven limb that mobilizes internal calcium. To understand the crosstalk between the two signaling cascades, we applied known AR inhibitors in three experimental approaches: reversible, stage-specific blockers in a functional assay, a far-immunofluorescence protocol to detect active Rab3 and Rap, and single cell-confocal microscopy to visualize fluctuations in internal calcium stores. Our model system was human sperm with their plasma membrane permeabilized with streptolysin O and stimulated with external calcium. The inhibition caused by reagents that prevented the activation of Rap was reversed by mobilizing intracellular calcium pharmacologically, whereas that caused by AR inhibitors that impeded Rab3's binding to GTP was not. Both limbs of the exocytotic cascade joined at or near the stage catalyzed by Rab3 in a unidirectional, hierarchical connection in which the intra-acrosomal calcium mobilization arm was subordinated to the fusion protein arm; somewhere after Rab3, the pathways became independent. We delineated the sequence of events that connect an external calcium signal to internal calcium mobilization during exocytosis. We have taken advantage of the versatility of the sperm model to investigate how cAMP, calcium, and the proteinaceous fusion machinery coordinate to accomplish secretion. Because the requirement of calcium from two different sources is not unique to sperm and fusion proteins are highly conserved, our findings might contribute to elucidate mechanisms that operate in regulated exocytosis in other secretory cell types.

  11. Removal of triclosan via peroxidases-mediated reactions in water: Reaction kinetics, products and detoxification.

    Li, Jianhua; Peng, Jianbiao; Zhang, Ya; Ji, Yuefei; Shi, Huanhuan; Mao, Liang; Gao, Shixiang


    This study investigated and compared reaction kinetics, product characterization, and toxicity variation of triclosan (TCS) removal mediated by soybean peroxidase (SBP), a recognized potential peroxidase for removing phenolic pollutants, and the commonly used horseradish peroxidase (HRP) with the goal of assessing the technical feasibility of SBP-catalyzed removal of TCS. Reaction conditions such as pH, H2O2 concentration and enzyme dosage were found to have a strong influence on the removal efficiency of TCS. SBP can retain its catalytic ability to remove TCS over broad ranges of pH and H2O2 concentration, while the optimal pH and H2O2 concentration were 7.0 and 8μM, respectively. 98% TCS was removed with only 0.1UmL(-1) SBP in 30min reaction time, while an HRP dose of 0.3UmL(-1) was required to achieve the similar conversion. The catalytic performance of SBP towards TCS was more efficient than that of HRP, which can be explained by catalytic rate constant (KCAT) and catalytic efficiency (KCAT/KM) for the two enzymes. MS analysis in combination with quantum chemistry computation showed that the polymerization products were generated via CC and CO coupling pathways. The polymers were proved to be nontoxic through growth inhibition of green alga (Scenedesmus obliquus). Taking into consideration of the enzymatic treatment cost, SBP may be a better alternative to HRP upon the removal and detoxification of TCS in water/wastewater treatment.

  12. Loss of Zona Pellucida Binding Proteins in the Acrosomal Matrix Disrupts Acrosome Biogenesis and Sperm Morphogenesis▿ †

    Lin, Yi-Nan; Roy, Angshumoy; Yan, Wei; Burns, Kathleen H.; Matzuk, Martin M.


    Zona pellucida binding protein 1 (ZPBP1), a spermatid and spermatozoon protein that localizes to the acrosome, was originally identified in pigs and named for its binding to the oocyte zona pellucida. In an in silico search for germ cell-specific genes, Zpbp1 and its novel paralog, Zpbp2, were discovered and confirmed to be expressed only in the testes in both mice and humans. To study the in vivo functions of both ZPBP proteins, we disrupted Zpbp1 and Zpbp2 in mice. Males lacking ZPBP1 were sterile, with abnormal round-headed sperm morphology and no forward sperm motility. Ultrastructural studies demonstrated that absence of ZPBP1 prevents proper acrosome compaction, resulting in acrosome fragmentation and disruption of the Sertoli-spermatid junctions. Males null for ZPBP2 were subfertile, demonstrated aberrant acrosomal membrane invaginations, and produced dysmorphic sperm with reduced ability to penetrate zona pellucida. Molecular phylogenetic analysis of ZPBPs from amphibians, birds, and mammals suggests that these paralogous genes coevolved to play cooperative roles during spermiogenesis. Whereas ZPBP1 was discovered for an in vitro role in sperm-egg interactions, we have shown that both ZPBP proteins play an earlier structural role during spermiogenesis. PMID:17664285

  13. Removal of triclosan via peroxidases-mediated reactions in water: Reaction kinetics, products and detoxification

    Li, Jianhua; Peng, Jianbiao [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023 (China); Zhang, Ya [Nanjing Institute of Environmental Sciences, Ministry of Environmental Protection of the People’s Republic of China, Nanjing 210042 (China); Ji, Yuefei [College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing 210095 (China); Shi, Huanhuan; Mao, Liang [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023 (China); Gao, Shixiang, E-mail: [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023 (China)


    Highlights: • Enzymatic treatment of triclosan in water by soybean and horseradish peroxidases. • pH, H{sub 2}O{sub 2} concentration and enzyme dosage affected the removal efficiency of TCS. • The removal of TCS by SBP was more efficient than that of HRP. • K{sub CAT} and K{sub CAT}/K{sub M} values for SBP toward TCS were much higher than those for HRP. • Polymers formed via radical coupling mechanism were nontoxic to the growth of alga. - Abstract: This study investigated and compared reaction kinetics, product characterization, and toxicity variation of triclosan (TCS) removal mediated by soybean peroxidase (SBP), a recognized potential peroxidase for removing phenolic pollutants, and the commonly used horseradish peroxidase (HRP) with the goal of assessing the technical feasibility of SBP-catalyzed removal of TCS. Reaction conditions such as pH, H{sub 2}O{sub 2} concentration and enzyme dosage were found to have a strong influence on the removal efficiency of TCS. SBP can retain its catalytic ability to remove TCS over broad ranges of pH and H{sub 2}O{sub 2} concentration, while the optimal pH and H{sub 2}O{sub 2} concentration were 7.0 and 8 μM, respectively. 98% TCS was removed with only 0.1 U mL{sup −1} SBP in 30 min reaction time, while an HRP dose of 0.3 U mL{sup −1} was required to achieve the similar conversion. The catalytic performance of SBP towards TCS was more efficient than that of HRP, which can be explained by catalytic rate constant (K{sub CAT}) and catalytic efficiency (K{sub CAT}/K{sub M}) for the two enzymes. MS analysis in combination with quantum chemistry computation showed that the polymerization products were generated via C−C and C−O coupling pathways. The polymers were proved to be nontoxic through growth inhibition of green alga (Scenedesmus obliquus). Taking into consideration of the enzymatic treatment cost, SBP may be a better alternative to HRP upon the removal and detoxification of TCS in water

  14. Multicomponent asymmetric reactions mediated by proline lithium salt

    Renzi, Polyssena; Overgaard, Jacob; Bella, Marco


    The multicomponent reaction between proline lithium salt, 2-cyclohexen-1-one and aliphatic aldehydes affords the 4- alkylidene-2-cyclohexen-1-ones, which are interesting fragrances, and bicyclic amino acids that bear four additional stereocenters, obtained as single stereoisomer....

  15. Polyfunctionalized pyrrolidines by Ugi multicomponent reaction followed by palladium-mediated SN2' cyclizations.

    Banfi, Luca; Basso, Andrea; Cerulli, Valentina; Guanti, Giuseppe; Riva, Renata


    A 4-component Ugi reaction with a suitable isocyanide, followed by a novel secondary transformation involving a Pd(II)-mediated (R5 = H) or a Pd(0)-mediated (R5 = CO2Me) SN2' cyclization to give highly functionalized N-acyl-2-vinylpyrrolidines, is reported. The overall yields are usually good and in most cases the Pd(0)-catalyzed reaction gave the final product in almost quantitative yield.

  16. Mediated priming in the lexical decision task : Evidence from event-related potentials and reaction time

    Chwilla, DJ; Kolk, HHJ; Mulder, G

    Mediated priming (e.g., from LION to STRIPES vis TIGER) is predicted by spreading activation models hut only by some integration model. The goal of the present research was to localize mediated priming by assessing two-step priming effects on N400 and reaction times (RT). We propose that the N400

  17. Mediated priming in the lexical decision task : Evidence from event-related potentials and reaction time

    Chwilla, DJ; Kolk, HHJ; Mulder, G


    Mediated priming (e.g., from LION to STRIPES vis TIGER) is predicted by spreading activation models hut only by some integration model. The goal of the present research was to localize mediated priming by assessing two-step priming effects on N400 and reaction times (RT). We propose that the N400 pr

  18. Inflammatory Mediators of Leprosy Reactional Episodes and Dental Infections: A Systematic Review

    Cortela, D. C. B.; de Souza Junior, A. L.; Virmond, M. C. L.; Ignotti, E.


    Reactional episodes in leprosy are a result of complex interactions between the immune system, Mycobacterium leprae, and predisposing factors, including dental infections. To determine the main inflammatory mediators in the immunopathological process of dental infections and leprosy reactions, we conducted a systematic review of primary literature published between 1996 and 2013. A three-stage literature search was performed (Stage I, “leprosy reactions” and “inflammatory mediators”; Stage II, “dental infections” and “inflammatory mediators”; and Stage III, “leprosy reactions,” “dental infections,” and “inflammatory mediators”). Of the 911 eligible publications, 10 were selected in Stage I, 68 in Stage II, and 1 in Stage III. Of the 27 studied inflammatory mediators, the main proinflammatory mediators were IL-6, IFN-γ, TNF-α, IL-1β, and IL-17; the main anti-inflammatory mediators were IL-10 and IL-4. Serum IL-6 and TNF-α concentrations were significant during periodontal and reactional lesion evolution; IFN-γ and IL-1β were associated with types 1 and 2 reactions and chronic periodontal disease. The proinflammatory mediators in dental infections and leprosy reactions, especially IL-6 and TNF-α, were similar across studies, regardless of the laboratory technique and sample type. IFN-γ and IL-1β were significant for leprosy reactions and periodontal diseases. This pattern was maintained in serum. PMID:26339136

  19. Synthesis of novel photochromic pyrans via palladium-mediated reactions

    Böttcher, Christoph; Zeyat, Gehad; Ahmed, Saleh A.; Irran, Elisabeth; Cordes, Thorben; Elsner, Cord; Zinth, Wolfgang; Rueck-Braun, Karola


    Photochromic pyrans for applications in material and life sciences were synthesized via palladium-mediated cyanation, carbonylation and Sonogashira cross-coupling starting from a bromo-substituted naphthopyran and benzopyrans. A novel photoswitchable benzopyran-based ω-amino acid for Fmoc-based soli

  20. Solvent-free microwave-mediated Michael addition reactions

    H Surya Prakash Rao; S Jothilingam


    Facile Michael addition of active methylene compounds to ,-unsaturated carbonyl compounds takes place on the surface of potassium carbonate under microwave irradiation. Further studies on microwave-mediated Robinson annulations reveal a convenient and facile method for condensation of chalcone with methylene compounds to furnish cyclohexenones.

  1. Polymerase chain reaction-mediated DNA fingerprinting for epidemiological studies on Campylobacter spp

    Giesendorf, B A; Goossens, H; Niesters, H G; Van Belkum, A; Koeken, A; Endtz, H P; Stegeman, H; Quint, W G


    The applicability of polymerase chain reaction (PCR)-mediated DNA typing, with primers complementary to dispersed repetitive DNA sequences and arbitrarily chosen DNA motifs, to study the epidemiology of campylobacter infection was evaluated. With a single PCR reaction and simple gel electrophoresis,

  2. Polymerase chain reaction-mediated DNA fingerprinting for epidemiological studies on Campylobacter spp

    Giesendorf, B A; Goossens, H; Niesters, H G; Van Belkum, A; Koeken, A; Endtz, H P; Stegeman, H; Quint, W G

    The applicability of polymerase chain reaction (PCR)-mediated DNA typing, with primers complementary to dispersed repetitive DNA sequences and arbitrarily chosen DNA motifs, to study the epidemiology of campylobacter infection was evaluated. With a single PCR reaction and simple gel electrophoresis,

  3. Towards a General Understanding of Carbonyl-Stabilised Ammonium Ylide-Mediated Epoxidation Reactions.

    Novacek, Johanna; Roiser, Lukas; Zielke, Katharina; Robiette, Raphaël; Waser, Mario


    The key factors for carbonyl-stabilised ammonium ylide-mediated epoxidation reactions were systematically investigated by experimental and computational means and the hereby obtained energy profiles provide explanations for the observed experimental results. In addition, we were able to identify the first tertiary amine-based chiral auxiliary that allows for high enantioselectivities and high yields for such epoxidation reactions.

  4. Decolorization and degradation of dyes with mediated fenton reaction.

    Goodell, Barry; Qian, Yuhui; Jellison, Jody; Richard, Mike


    A mediated Fenton system has been evaluated for decolorization of several types of dyes. The result shows that the Fenton system with a dihydroxybenzoic acid (DHBA) chelator-mediator effectively reduced the color of a diluted solution of Carta Yellow RW liquid, Carta Yellow G liquid, and Cartasol Red 2GF liquid dye to a colorless level after 90 minutes of treatment with 100 microM iron II (Fe[II]), 100 microM DHBA, and 10 mM hydrogen peroxide (H2O2) at room temperature. Our results show that compared to a neat Fenton process, the mediated Fenton decolorization process increased the production, and therefore the effective longevity, of hydroxyl radical (OH) species to increase the decolorization efficiency. Our results suggest that application of this system would also result in an increase in dissolved oxygen (DO) in solution, which in turn would result in reduction of chemical oxygen demand (COD), biochemical oxygen demand (BOD), and total organic carbon (TOC).

  5. Engaging unactivated alkyl, alkenyl and aryl iodides in visible-light-mediated free radical reactions.

    Nguyen, John D; D'Amato, Erica M; Narayanam, Jagan M R; Stephenson, Corey R J


    Radical reactions are a powerful class of chemical transformations. However, the formation of radical species to initiate these reactions has often required the use of stoichiometric amounts of toxic reagents, such as tributyltin hydride. Recently, the use of visible-light-mediated photoredox catalysis to generate radical species has become popular, but the scope of these radical precursors has been limited. Here, we describe the identification of reaction conditions under which photocatalysts such as fac-Ir(ppy)3 can be utilized to form radicals from unactivated alkyl, alkenyl and aryl iodides. The generated radicals undergo reduction via hydrogen atom abstraction or reductive cyclization. The reaction protocol utilizes only inexpensive reagents, occurs under mild reaction conditions, and shows exceptional functional group tolerance. Reaction efficiency is maintained upon scale-up and decreased catalyst loading, and the reaction time can be significantly shortened when the reaction is performed in a flow reactor.

  6. Synthesis of novel photochromic pyrans via palladium-mediated reactions

    Christoph Böttcher


    Full Text Available Photochromic pyrans for applications in material and life sciences were synthesized via palladium-mediated cyanation, carbonylation and Sonogashira cross-coupling starting from bromo-substituted naphthopyran 1 and benzopyrans 2a/b. A novel photoswitchable benzopyran-based ω-amino acid 6 for Fmoc-based solid-phase peptide synthesis is presented. The photochromic behaviour of the 3-cyano-substituted benzopyran 5a was investigated by time-resolved absorption spectroscopy in the picosecond time domain.

  7. Notch-mediated lateral inhibition regulates proneural wave propagation when combined with EGF-mediated reaction diffusion.

    Sato, Makoto; Yasugi, Tetsuo; Minami, Yoshiaki; Miura, Takashi; Nagayama, Masaharu


    Notch-mediated lateral inhibition regulates binary cell fate choice, resulting in salt and pepper patterns during various developmental processes. However, how Notch signaling behaves in combination with other signaling systems remains elusive. The wave of differentiation in the Drosophila visual center or "proneural wave" accompanies Notch activity that is propagated without the formation of a salt and pepper pattern, implying that Notch does not form a feedback loop of lateral inhibition during this process. However, mathematical modeling and genetic analysis clearly showed that Notch-mediated lateral inhibition is implemented within the proneural wave. Because partial reduction in EGF signaling causes the formation of the salt and pepper pattern, it is most likely that EGF diffusion cancels salt and pepper pattern formation in silico and in vivo. Moreover, the combination of Notch-mediated lateral inhibition and EGF-mediated reaction diffusion enables a function of Notch signaling that regulates propagation of the wave of differentiation.

  8. Alkali metal mediated C-C bond coupling reaction.

    Tachikawa, Hiroto


    Metal catalyzed carbon-carbon (C-C) bond formation is one of the important reactions in pharmacy and in organic chemistry. In the present study, the electron and hole capture dynamics of a lithium-benzene sandwich complex, expressed by Li(Bz)2, have been investigated by means of direct ab-initio molecular dynamics method. Following the electron capture of Li(Bz)2, the structure of [Li(Bz)2](-) was drastically changed: Bz-Bz parallel form was rapidly fluctuated as a function of time, and a new C-C single bond was formed in the C1-C1' position of Bz-Bz interaction system. In the hole capture, the intermolecular vibration between Bz-Bz rings was only enhanced. The mechanism of C-C bond formation in the electron capture was discussed on the basis of theoretical results.

  9. Automatic classification of the acrosome status of boar spermatozoa using digital image processing and LVQ

    Alegre, Enrique; Biehl, Michael; Petkov, Nicolai; Sanchez, Lidia


    We consider images of boar spermatozoa obtained with ail optical phase-contrast microscope. Our goal is to automatically classify single sperm cells as acrosome-intact (class 1) or acrosome-damaged (class 2). Such classification is important for the estimation of the fertilization potential of a spe

  10. Modern human sperm freezing: Effect on DNA, chromatin and acrosome integrity

    Tahereh Rahiminia


    Conclusion: Sperm in Vapour was healthier in terms of DNA, chromatin and acrosome integrity. In contrast of higher motility and normal morphology; DNA, chromatin and acrosome integrity were decreased in Vit. However, these findings were more acceptable in SSV or Vapour.

  11. Inflammatory Mediators of Leprosy Reactional Episodes and Dental Infections: A Systematic Review

    Cortela, D. C. B.; de Souza Junior, A. L.; M. C. L. Virmond; E. Ignotti


    Reactional episodes in leprosy are a result of complex interactions between the immune system, Mycobacterium leprae, and predisposing factors, including dental infections. To determine the main inflammatory mediators in the immunopathological process of dental infections and leprosy reactions, we conducted a systematic review of primary literature published between 1996 and 2013. A three-stage literature search was performed (Stage I, “leprosy reactions” and “inflammatory mediators”; Stage II...

  12. Coupling Reaction of Carbonyl Compounds Mediated by Gallium Metal in Aqueous Media

    汪志勇; 袁仕祯; 查正根; 张祖德


    A simple and effective pinacol coupling of various aromatic aldehydes mediated by gallium in good yields has been carried out. The reaction is highly effective in water in the prurience of KOH or HCl and was strongly affected by the steric environ-ment surrounding the carbonyl group. Aliphaflc aldehydes, ke-tones and aromatic ketones appear inert under the same reac-tion conditions.


    B. K. Satriyasa


    Full Text Available Background: caffeine, a methylxanthine derivate, appears to inhibit phosphodiesterase, thereby inhibiting the break down of cAMP and increasing its concentration inside cell. This study aims to assess the effect of caffeine addition in Earles’s Balanced Salt Solution (EBSS on the increase in membrane integrity and acrosome reaction of spermatozoa using swim up method. Methods: This study was carried out at the Clinic of Sexology and Andrology, Sanglah Public Hospital at Denpasar Bali-Indonesia. This study was an experimental study using the design of pre and post test paired control group design. The samples were sperm specimens of eighteen infertile couple male or volunteers who were infertile with age ranged between 20-40 years old. The samples   were divided into two groups: treatment group (caffeine + EBSS and control group (EBSS. The data were analysed statistically by normality test (Kolmogorov - Smirnov Goodness of Fit Test, Homogeneity test, and Paired Student’s t test.  Results: The results showed that the caffeine addition in EBSS medium could increase significantly (p<0.05.  The integrity of the sperm membrane obtained were from 81.30 % to 86.60 % and acrosomal reaction from 82.60% to 89.60% evaluated by hypo-osmotic swelling test (HOS. The conclusion of this study is that addition of caffeine in EBSS medium increases significantly membrane integrity and acrosomal reaction of the human sperm.

  14. Phosphoric Acid-Mediated Synthesis of Vinyl Sulfones through Decarboxylative Coupling Reactions of Sodium Sulfinates with Phenylpropiolic Acids.

    Rong, Guangwei; Mao, Jincheng; Yan, Hong; Zheng, Yang; Zhang, Guoqi


    A novel phosphoric acid -mediated synthesis of vinyl sulfones through decarboxylative coupling reactions of sodium sulfinates with phenylpropiolic acids is described. This transformation is efficient and environmentally friendly.

  15. Genes encoding phospholipases A2 mediate insect nodulation reactions to bacterial challenge.

    Shrestha, Sony; Park, Yoonseong; Stanley, David; Kim, Yonggyun


    We propose that expression of four genes encoding secretory phospholipases A(2) (sPLA(2)) mediates insect nodulation responses to bacterial infection. Nodulation is the quantitatively predominant cellular defense reaction to bacterial infection. This reaction is mediated by eicosanoids, the biosynthesis of which depends on PLA(2)-catalyzed hydrolysis of arachidonic acid (AA) from cellular phospholipids. Injecting late instar larvae of the red flour beetle, Tribolium castaneum, with the bacterium, Escherichia coli, stimulated nodulation reactions and sPLA(2) activity in time- and dose-related manners. Nodulation was inhibited by pharmaceutical inhibitors of enzymes involved in eicosanoid biosynthesis, and the inhibition was rescued by AA. We cloned five genes encoding sPLA(2) and expressed them in E. coli cells to demonstrate these genes encode catalytically active sPLA(2)s. The recombinant sPLA(2)s were inhibited by sPLA(2) inhibitors. Injecting larvae with double-stranded RNAs specific to each of the five genes led to reduced expression of the corresponding sPLA(2) genes and to reduced nodulation reactions to bacterial infections for four of the five genes. The reduced nodulation was rescued by AA, indicating that expression of four genes encoding sPLA(2)s mediates nodulation reactions. A polyclonal antibody that reacted with all five sPLA(2)s showed the presence of the sPLA(2) enzymes in hemocytes and revealed that the enzymes were more closely associated with hemocyte plasma membranes following infection. Identifying specific sPLA(2) genes that mediate nodulation reactions strongly supports our hypothesis that sPLA(2)s are central enzymes in insect cellular immune reactions. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  16. Site-specific N-terminal labeling of proteins using sortase-mediated reactions

    Theile, Christopher S.; Witte, Martin D.; Blom, Annet E. M.; Kundrat, Lenka; Ploegh, Hidde L.; Guimaraes, Carla P.


    This protocol describes the use of sortase-mediated reactions to label the N terminus of any given protein of interest. The sortase recognition sequence, LPXTG (for Streptococcus aureus sortase A) or LPXTA (for Staphylococcus pyogenes sortase A), can be appended to a variety of probes such as fluoro

  17. Eicosanoids mediate nodulation reactions to a Mollicute bacterium in larvae of the blowfly, Chrysomya megacephala

    Nodulation is the temporally and quantitatively most important cellular defense response to bacterial, fungal and some viral infections in insects. We tested the hypothesis that prostaglandins and other eicosanoids are responsible for mediating nodulation reactions to bacterial infection in larvae o...

  18. Effect of disodium cromoglycate on mast cell-mediated immediate-type allergic reactions.

    Shin, Hye-Young; Kim, Jung-Sook; An, Nyeon-Hyoung; Park, Rae-Kil; Kim, Hyung-Min


    We investigated the effect of disodium cromoglycate (DSCG) on mast cell-mediated immediate-type hypersensitivity. DSCG inhibited systemic allergic reaction induced by compound 48/80 dose-dependently. Passive cutaneous anaphylaxis was inhibited by 71.6% by oral administration of DSCG (1 g/kg). When DSCG was pretreated at concentration rang from 0.01-1000 g/kg, the serum histamine levels were reduced in a dose dependent manner. DSCG also significantly inhibited histamine release from rat peritoneal mast cell (RPMC) by compound 48/80. We confirmed that DSCG inhibited compound 48/80-induced degranulation of RPMC by alcian blue/nuclear fast red staining. In addition, DSCG showed a significant inhibitory effect on anti-dinitrophenyl IgE-mediated tumor necrosis factor-alpha production. These results indicate that DSCG inhibits mast cell-mediated immediate-type allergic reaction.

  19. Suicide Disclosure in Suicide Attempt Survivors: Does Family Reaction Moderate or Mediate Disclosure's Effect on Depression?

    Frey, Laura M; Hans, Jason D; Cerel, Julie


    Existing literature has found a link between disclosure of a stigmatized identity and improved mental health; however, research on the impact of suicide disclosure to family members is scarce. Suicide attempt survivors (n = 74) in the United States were examined to assess whether family reaction moderates or mediates the relationship between suicide disclosure and subsequent depression symptoms. Family reaction did not moderate but did mediate the relationship between disclosure and depression symptoms while controlling for time since most recent attempt. Higher rates of disclosure predicted more positive family reactions, which in turn predicted less severe depression symptoms. Findings indicate that family members can play an essential role in the recovery process after an attempt occurs, which has important implications for both researchers and clinicians who seek to decrease stigma for attempt survivors while simultaneously decreasing the likelihood of future attempts.

  20. Origin of Power Laws for Reactions at Metal Surfaces Mediated by Hot Electrons

    Olsen, Thomas; Schiøtz, Jakob


    A wide range of experiments have established that certain chemical reactions at metal surfaces can be driven by multiple hot-electron-mediated excitations of adsorbates. A high transient density of hot electrons is obtained by means of femtosecond laser pulses and a characteristic feature...... of such experiments is the emergence of a power law dependence of the reaction yield on the laser fluence Y similar to F-n. We propose a model of multiple inelastic scattering by hot electrons which reproduces this power law and the observed exponents of several experiments. All parameters are calculated within...

  1. Effect of caprine testicular extract on acrosome formation of spermatids of lead-injured mice

    Hong-yan TIAN


    Full Text Available Objective  To investigate the effect of caprine testicular extract on the acrosomal formation of spermatids of lead-treated mice, and find a theoretical and experimental basis for further research on the effects of caprine testicular extract on the reproductive system. Methods The study was carried out on thirty male adult ICR mice, which were randomly assigned into control group, model group and treatment group (10 each. The testis-injury model was reproduced by intragastric administration of lead acetate (30mg/kg, 0.1ml/10g. Animals in treatment group received intragastric administration of lead acetate and intraabdominal injection of 0.5ml caprine testicular extract at the same time for 21days, and the mice in control group received the same amount of distilled water by intragastric administration and 0.5ml distilled water by intraabdominal injection. By the end of the experimental period, the mice were sacrificed. The testes were fixed by cardiac perfusion and processed for light microscopic examination. The acrosomal formation in round spermatids was observed by PAS staining. Results  Compared with the control group, the acrosomal formation in model group was blocked. Acrosomal vesicle was incomplete, the membrane was shrunken, rough and fuzzy. The acrosomal formation in treatment group was similar to that of the control group. The structure of the acrosomal vesicle was complete and the membrane was smooth. Conclusion  Administration of caprine testicular extract may protect the acrosomal formation of spermatids from lead poisoning, and the normal structure and function of the acrosome are preserved. Thus, indepth study of the effects of caprine testicular extract may contribute to the treatment of male infertility caused by heavy metal-induced testicular damage, and offer an effective protective measure for the lead-exposed males.

  2. Molecular Cloning of Spergen-4, Encoding a Spermatogenic Cell-Specific Protein Associated with Sperm Flagella and the Acrosome Region in Rat Spermatozoa.

    Howida, Ali; Salaheldeen, Elsaid; Iida, Hiroshi


    We used a differential display in combination with complementary DNA (cDNA) cloning approach to isolate a novel rat gene LOC690919 with an open reading frame of 1227-length nucleotides encoding a protein of 409 amino acids. This gene was designated as Spergen-4 (a spermatogenic cell-specific gene-4). Spergen-4 mRNA was highly expressed in testis, and its expression was detected in rat testis starting at three weeks of postnatal development and persisting up to adulthood. Mouse and human orthologs, which lack N-terminal 77 amino acid residues of rat Spegen-4, were found in the database. Immunofluorescence microscopy and immunoblot analysis demonstrated that Spergen-4 was not expressed in spermatogonia, spermatocytes, and round spermatids, but was restrictedly detected at sperm head, cytoplasm, and developing flagella of elongated spermatids in rat testis. In mature spermatozoa, Spergen-4 was detected at the acrosome region as well as the principal piece of flagella. Spergen-4 immunosignal disappeared from sperm heads on acrosome reaction induced by progesterone. These data suggest that Spergen-4 integrated into elongated spermatids during spermiogenesis serves as a constituent for acrosome region and flagella of rat spermatozoa.

  3. Single Photon Initiated Decomposition Rearrangement Reactions (spidrr) of Organic Molecules Mediated by the Ni+ Cation

    Bellert, Darrin; Mansell, Adam; Theis, Zachary; Gutierrez, Michael


    The Bellert group at Baylor University has developed a novel method for performing single photon initiated decomposition rearrangement reactions (SPIDRR) of organic molecules mediated by a transition metal cation. The advantage that SPIDRR affords is the direct measurement of first order microcanonical rate constants, k(E), determined at resolved internal energies. Furthermore, the SPIDRR technique measures kinetic details of exothermic reactions where product production is limited only by submerged activation barriers (kinetic barriers that are at energies below the separated reactant limit). Thus, such reactions approach unit efficiency, are thermodynamically driven, and are of greater relevance to catalytic research. Direct measurements of k(E) values extend to isotopically labelled species that provide direct measurement of the kinetic isotope effect (KIE), furnishing unique insight into the mechanistic details of a reaction. This talk presents results from the visible photon initiated, Ni+ induced decarbonylation reaction of propionaldehyde. Here a rather unique energy dependent behavior of the measured rate constants was observed and attributed to a dynamic competition between parallel reaction coordinates available to the photo-excited precursor. RRKM calculations in concert with high level DFT is used to support and further experimental results.

  4. Inhibitory effects of atractylone on mast cell-mediated allergic reactions.

    Han, Na-Ra; Moon, Phil-Dong; Nam, Sun-Young; Ryu, Ka-Jung; Yoou, Myoung-Schook; Choi, Jung-Hye; Hwang, Sung-Yeoun; Kim, Hyung-Min; Jeong, Hyun-Ja


    This study investigated a salutary effect of atractylone (Atr) which is an active constituent of Pyeongwee-San (KMP6) on mast cell-mediated allergic reactions. Our previous report indicated that KMP6 regulated allergic reactions. Thus, this study sought to determine the potential of Atr in vitro models, compound 48/80-stimulated rat peritoneal mast cells (RPMCs), phorbol 12-myristate 13-acetate (PMA) plus A23187-stimulated human mast cell line (HMC-1) cells, and stem cell factor (SCF)-stimulated RPMCs as well as in vivo models, IgE-mediated passive cutaneous anaphylaxis (PCA), compound 48/80-induced systemic anaphylaxis, and compound 48/80-induced ear swelling. The results showed that Atr inhibited compound 48/80-induced RPMCs degranulation, intracellular calcium level, tryptase release, and histamine release. Atr inhibited the up-regulation of p56(lck) tyrosine kinase activity by compound 48/80. And Atr reduced tryptase and histamine releases from PMA plus A23187-stimulated HMC-1 cells. In addition, Atr decreased histidine decarboxylase activity and expression in the activated HMC-1 cells. Atr inhibited SCF-induced morphological alteration and filamentous actin formation in RPMCs. Atr improved IgE-induced PCA reaction by decreasing the levels of histamine, IgE, interleukin (IL)-4, IL-5, IL-6, vascular endothelial growth factor, and IL-13 in the serum of PCA-induced mice. Furthermore, Atr mitigated compound 48/80-induced systemic anaphylaxis and ear swelling. Taken together, these results of this study indicate that Atr regulates the degranulation of mast cell, proving its potential in the treatment of mast cell-mediated allergic reactions.

  5. Immunoglobulin E-mediated hypersensitivity reaction after intraperitoneal administration of vancomycin

    Mun-Ju Hwang


    Full Text Available Intraperitoneal (IP vancomycin is widely used to treat Gram-positive peritonitis associated with peritoneal dialysis. There have been two cases of red man syndrome (RMS, a vancomycin-specific nonimmunologic reaction, associated with IP vancomycin. However, immune-mediated hypersensitivity reaction to IP vancomycin has not yet been reported. A 49 year old woman on continuous ambulatory peritoneal dialysis developed her first peritonitis episode. The patient was treated with IP vancomycin once/wk for 4 weeks. She experienced mild itching and flushing throughout her body for 1 day after the second treatment. Whenever vancomycin was administered, generalized urticaria and a prickling sensation developed, and the intensity increased gradually; however, these symptoms improved after vancomycin was discontinued. An allergic skin test was performed 6 weeks after the previous urticarial episode, and an intradermal skin test revealed a positive response to vancomycin. To our knowledge, this is the first case report of immunoglobulin E-mediated hypersensitivity reaction to IP vancomycin administration.

  6. Pinacol Coupling Reaction of Benzaldehyde Mediated by TiCl3-Zn in Basic Media Under Ultrasound Irradiation

    Wang Shu-Xiang


    Full Text Available Pinacol coupling of benzaldehyde mediated by TiCl3-Zn in basic media under ultrasound irradiation can lead to the corresponding pinacol rapidly. The optimum reaction condition is chosen.

  7. Proton mediated control of biochemical reactions with bioelectronic pH modulation

    Deng, Yingxin; Miyake, Takeo; Keene, Scott; Josberger, Erik E.; Rolandi, Marco


    In Nature, protons (H+) can mediate metabolic process through enzymatic reactions. Examples include glucose oxidation with glucose dehydrogenase to regulate blood glucose level, alcohol dissolution into carboxylic acid through alcohol dehydrogenase, and voltage-regulated H+ channels activating bioluminescence in firefly and jellyfish. Artificial devices that control H+ currents and H+ concentration (pH) are able to actively influence biochemical processes. Here, we demonstrate a biotransducer that monitors and actively regulates pH-responsive enzymatic reactions by monitoring and controlling the flow of H+ between PdHx contacts and solution. The present transducer records bistable pH modulation from an “enzymatic flip-flop” circuit that comprises glucose dehydrogenase and alcohol dehydrogenase. The transducer also controls bioluminescence from firefly luciferase by affecting solution pH.

  8. Remodeling of the plasma membrane in preparation for sperm-egg recognition: roles of acrosomal proteins.

    Tanphaichitr, Nongnuj; Kongmanas, Kessiri; Kruevaisayawan, Hathairat; Saewu, Arpornrad; Sugeng, Clarissa; Fernandes, Jason; Souda, Puneet; Angel, Jonathan B; Faull, Kym F; Aitken, R John; Whitelegge, Julian; Hardy, Daniel; Berger, Trish; Baker, Mark


    The interaction of sperm with the egg's extracellular matrix, the zona pellucida (ZP) is the first step of the union between male and female gametes. The molecular mechanisms of this process have been studied for the past six decades with the results obtained being both interesting and confusing. In this article, we describe our recent work, which attempts to address two lines of questions from previous studies. First, because there are numerous ZP binding proteins reported by various researchers, how do these proteins act together in sperm-ZP interaction? Second, why do a number of acrosomal proteins have ZP affinity? Are they involved mainly in the initial sperm-ZP binding or rather in anchoring acrosome reacting/reacted spermatozoa to the ZP? Our studies reveal that a number of ZP binding proteins and chaperones, extracted from the anterior sperm head plasma membrane, coexist as high molecular weight (HMW) complexes, and that these complexes in capacitated spermatozoa have preferential ability to bind to the ZP. Zonadhesin (ZAN), known as an acrosomal protein with ZP affinity, is one of these proteins in the HMW complexes. Immunoprecipitation indicates that ZAN interacts with other acrosomal proteins, proacrosin/acrosin and sp32 (ACRBP), also present in the HMW complexes. Immunodetection of ZAN and proacrosin/acrosin on spermatozoa further indicates that both proteins traffic to the sperm head surface during capacitation where the sperm acrosomal matrix is still intact, and therefore they are likely involved in the initial sperm-ZP binding step.

  9. Acrosome-specific gene AEP1: identification, characterization and roles in spermatogenesis.

    Luk, John M; Lee, Nikki P Y; Shum, Cathy K; Lam, Brian Y; Siu, Annie F M; Che, Chi-Ming; Tam, Po-Chor; Cheung, Annie N Y; Yang, Z M; Lin, Yi-Nan; Matzuk, Martin M; Lee, Kai-Fai; Yeung, William S B


    Spermatogenesis is a tightly regulated process leading to the development of spermatozoa. To elucidate the molecular spermatogenic mechanisms, we identified an acrosome-specific gene AEP1 in spermatids, which is located in rat chromosome 17p14 with a transcript size of 3,091 bp encoding a signal peptide, zinc finger-like motif, coiled-coil region, several predicted glycosylation and phosphorylation sites. Northern blot and RT-PCR analyses revealed the restricted expression of AEP1 to the testis only. In postnatal rat testes, AEP1 mRNA became detectable from postnatal 25 dpp (round spermatids) and onwards. By using in situ hybridization (ISH) and flow cytometry-fluorescent ISH, only the haploid spermatids yielded the positive AEP1 signal. Immunohistochemistry showed that AEP1 was expressed in the acrosomal cap of late-staged germ cells in rat testis, and co-localized with the acrosomal marker, peanut agglutinin. The spatial expression of AEP1 immunoreactivity in testis was conserved among diverse mammalian species (rat, pig, monkey, human). To further study its roles in spermatogenesis, we showed AEP1 and beta-actin was associated together in complex by co-immunoprecipitation in adult germ cells and by immunofluorescence assay in isolated spermatozoon. In human testes diagnosed with hypospermatogenesis, lower expression of AEP1 was observed, whereas there was no detectable signal in undescended testes. In short, AEP1 is an evolutionary-conserved acrosome-specific gene and likely functions in acrosome-cap formation.

  10. Hypochlorous acid-mediated protein oxidation: how important are chloramine transfer reactions and protein tertiary structure?

    Pattison, David I; Hawkins, Clare L; Davies, Michael J


    Hypochlorous acid (HOCl) is a powerful oxidant generated from H2O2 and Cl- by the heme enzyme myeloperoxidase, which is released from activated leukocytes. HOCl possesses potent antibacterial properties, but excessive production can lead to host tissue damage that occurs in numerous human pathologies. As proteins and amino acids are highly abundant in vivo and react rapidly with HOCl, they are likely to be major targets for HOCl. In this study, two small globular proteins, lysozyme and insulin, have been oxidized with increasing excesses of HOCl to determine whether the pattern of HOCl-mediated amino acid consumption is consistent with reported kinetic data for isolated amino acids and model compounds. Identical experiments have been carried out with mixtures of N-acetyl amino acids (to prevent reaction at the alpha-amino groups) that mimic the protein composition to examine the role of protein structure on reactivity. The results indicate that tertiary structure facilitates secondary chlorine transfer reactions of chloramines formed on His and Lys side chains. In light of these data, second-order rate constants for reactions of Lys side chain and Gly chloramines with Trp side chains and disulfide bonds have been determined, together with those for further oxidation of Met sulfoxide by HOCl and His side chain chloramines. Computational kinetic models incorporating these additional rate constants closely predict the experimentally observed amino acid consumption. These studies provide insight into the roles of chloramine formation and three-dimensional structure on the reactions of HOCl with isolated proteins and demonstrate that kinetic models can predict the outcome of HOCl-mediated protein oxidation.

  11. Assessing the reaction conditions to mediate the milkfat-soybean oil enzymatic interesterification

    Ariela Veloso de Paula

    Full Text Available Summary A food grade lipase from Rhizopus oryzae immobilized on a hybrid polysiloxane-polyvinyl alcohol matrix (SiO2-PVA was used as the biocatalyst to mediate the interesterification reactions of a blend containing 65% milkfat and 35% soybean oil. All the reactions occurred in an inert nitrogen atmosphere in cylindrical glass reactors (80 mL with 40 g of the milkfat-soybean oil blend. The influence of the following variables was evaluated: biocatalyst loading (250-1500 activity units per gram of blend, biocatalyst moisture content (5-20%, temperature (45-60 °C and incubation time (2-48 h. The reactions were monitored by determining the free fatty acid content, triacylglycerol (TAGs composition in carbon species, and the consistency of the interesterified (IE products. The reaction conditions were set based on the parameters that provided a high interesterification yield and good consistency of the final product within the ideal range (200 to 800 gf cm-2. Hence the best results were obtained using a biocatalyst loading of 500 U g-1 of blend with 10% moisture content at 45 °C for 4 h. Under these conditions the consistency of the interesterified product was 539.7 ± 38 gf cm-2. The results demonstrated the potential of the immobilized lipase to alter the TAGs profile of the milkfat-soybean oil blend, allowing for the production of structured lipids.

  12. Zinc-mediated one-pot tandem reaction of nitriles with propargyl bromides: an access to 3-alkynylpyridines.

    He, Yan; Guo, Shenghai; Zhang, Xinying; Fan, Xuesen


    A one-pot procedure for the synthesis of 3-alkynylpyridines via a zinc-mediated tandem reaction of nitriles with propargyl bromides under extremely mild reaction conditions has been developed. This reaction exhibits high efficiency, broad substrate scope, and good functional group tolerance. In addition, the 3-alkynylpyridines obtained herein were found to be versatile and convenient intermediates for the preparation of fused-heterocyclic compounds with potential biological and material interests.

  13. Silymarin protects plasma membrane and acrosome integrity in sperm treated with sodium arsenite

    Farzaneh Eskandari


    Full Text Available Background: Exposure to arsenic is associated with impairment of male reproductive function by inducing oxidative stress. Silymarin with an antioxidant property scavenges free radicals. Objective: The aim of this study was to investigate if silymarin can prevent the adverse effects of sodium arsenite on ram sperm plasma membrane and acrosome integrity. Materials and Methods: Ram epidydimal spermatozoa were divided into five groups: spermatozoa at 0 hr, spermatozoa at 180 min (control, spermatozoa treated with silymarin (20 μM + sodium arsenite (10 μM for 180 min, spermatozoa treated with sodium arsenite (10 μM for 180 min and spermatozoa treated with silymarin (20 μM for 180 min. Double staining of Hoechst and propidium iodide was performed to evaluate sperm plasma membrane integrity, whereas comassie brilliant blue staining was used to assess acrosome integrity. Results: Plasma membrane (p< 0.001 and acrosome integrity (p< 0.05 of the spermatozoa were significantly reduced in sodium arsenite group compared to the control. In silymarin + sodium arsenite group, silymarin was able to significantly (p< 0.001 ameliorate the adverse effects of sodium arsenite on these sperm parameters compared to sodium arsenite group. The incubation of sperm for 180 min (control group showed a significant (p< 0.001 decrease in acrosome integrity compared to the spermatozoa at 0 hour. The application of silymarin alone for 180 min could also significantly (p< 0.05 increase sperm acrosome integrity compared to the control. Conclusion: Silymarin as a potent antioxidant could compensate the adverse effects of sodium arsenite on the ram sperm plasma membrane and acrosome integrity.

  14. Involvement of complexin 2 in docking, locking and unlocking of different SNARE complexes during sperm capacitation and induced acrosomal exocytosis.

    Pei-Shiue J Tsai

    Full Text Available Acrosomal exocytosis (AE is an intracellular multipoint fusion reaction of the sperm plasma membrane (PM with the outer acrosomal membrane (OAM. This unique exocytotic event enables the penetration of the sperm through the zona pellucida of the oocyte. We previously observed a stable docking of OAM to the PM brought about by the formation of the trans-SNARE complex (syntaxin 1B, SNAP 23 and VAMP 3. By using electron microscopy, immunochemistry and immunofluorescence techniques in combination with functional studies and proteomic approaches, we here demonstrate that calcium ionophore-induced AE results in the formation of unilamellar hybrid membrane vesicles containing a mixture of components originating from the two fused membranes. These mixed vesicles (MV do not contain the earlier reported trimeric SNARE complex but instead possess a novel trimeric SNARE complex that contained syntaxin 3, SNAP 23 and VAMP 2, with an additional SNARE interacting protein, complexin 2. Our data indicate that the earlier reported raft and capacitation-dependent docking phenomenon between the PM and OAM allows a specific rearrangement of molecules between the two docked membranes and is involved in (1 recruiting SNAREs and complexin 2 in the newly formed lipid-ordered microdomains, (2 the assembly of a fusion-driving SNARE complex which executes Ca(2+-dependent AE, (3 the disassembly of the earlier reported docking SNARE complex, (4 the recruitment of secondary zona binding proteins at the zona interacting sperm surface. The possibility to study separate and dynamic interactions between SNARE proteins, complexin and Ca(2+ which are all involved in AE make sperm an ideal model for studying exocytosis.

  15. Giant, accordioned sperm acrosomes of the greater bulldog bat, Noctilio leporinus.

    Phillips, D M; Rasweiler, J J; Muradali, F


    Sperm of the greater bulldog bat Noctilio leporinus display an architecture that is totally unique among mammalian spermatozoa. The sperm head of Noctilio is extraordinarily large and flat and lies eccentrically with respect to the sperm tail. The major portion of the atypically large acrosome lies anterior to the nucleus and is shaped into a dozen accordionlike folds that run parallel to the long axis of the sperm. The ridge of each fold is shaped into approximately 60 minute, evenly spaced rises that extend along the entire length of the fold. We speculate that acrosome ridges may serve to strengthen the sperm head during transport.

  16. Carbon dioxide released from subduction zones by fluid-mediated reactions

    Ague, Jay J.; Nicolescu, Stefan


    The balance between the subduction of carbonate mineral-bearing rocks into Earth's mantle and the return of CO2 to the atmosphere by volcanic and metamorphic degassing is critical to the carbon cycle. Carbon is thought to be released from subducted rocks mostly by simple devolatilization reactions. However, these reactions will also retain large amounts of carbon within the subducting slab and have difficulty in accounting for the mass of CO2 emitted from volcanic arcs. Carbon release may therefore occur via fluid-induced dissolution of calcium carbonate. Here we use carbonate δ18O and δ13C systematics, combined with analyses of rock and fluid inclusion mineralogy and geochemistry, to investigate the alteration of the exhumed Eocene Cycladic subduction complex on the Syros and Tinos islands, Greece. We find that in marble rocks adjacent to two fluid conduits that were active during subduction, the abundance of calcium carbonate drastically decreases approaching the conduits, whereas silicate minerals increase. Up to 60-90% of the CO2 was released from the rocks--far greater than expected via simple devolatilization reactions. The δ18O of the carbonate minerals is 5-10 lighter than is typical for metamorphosed carbonate rocks, implying that isotopically light oxygen was transported by fluid infiltration from the surroundings. We suggest that fluid-mediated carbonate mineral removal, accompanied by silicate mineral precipitation, provides a mechanism for the release of enormous amounts of CO2 from subduction zones.

  17. Deformation-resembling microstructure created by fluid-mediated dissolution–precipitation reactions

    Spruzeniece, Liene; Piazolo, Sandra; Maynard-Casely, Helen E.


    Deformation microstructures are widely used for reconstructing tectono-metamorphic events recorded in rocks. In crustal settings deformation is often accompanied and/or succeeded by fluid infiltration and dissolution–precipitation reactions. However, the microstructural consequences of dissolution–precipitation in minerals have not been investigated experimentally. Here we conducted experiments where KBr crystals were reacted with a saturated KCl-H2O fluid. The results show that reaction products, formed in the absence of deformation, inherit the general crystallographic orientation from their parents, but also display a development of new microstructures that are typical in deformed minerals, such as apparent bending of crystal lattices and new subgrain domains, separated by low-angle and, in some cases, high-angle boundaries. Our work suggests that fluid-mediated dissolution–precipitation reactions can lead to a development of potentially misleading microstructures. We propose a set of criteria that may help in distinguishing such microstructures from the ones that are created by crystal-plastic deformation. PMID:28128202

  18. Coupling Solar Energy into Reactions: Materials Design for Surface Plasmon-Mediated Catalysis.

    Long, Ran; Li, Yu; Song, Li; Xiong, Yujie


    Enabled by surface plasmons, noble metal nanostructures can interact with and harvest incident light. As such, they may serve as unique media to generate heat, supply energetic electrons, and provide strong local electromagnetic fields for chemical reactions through different mechanisms. This solar-to-chemical pathway provides a new approach to solar energy utilization, alternative to conventional semiconductor-based photocatalysis. To provide readers with a clear picture of this newly recognized process, this review presents coupling solar energy into chemical reactions through plasmonic nanostructures. It starts with a brief introduction of surface plasmons in metallic nanostructures, followed by a demonstration of tuning plasmonic features by tailoring their physical parameters. Owing to their tunable plasmonic properties, metallic materials offer a platform to trigger and drive chemical reactions at the nanoscale, as systematically overviewed in this article. The design rules for plasmonic materials for catalytic applications are further outlined based on existing examples. At the end of this article, the challenges and opportunities for further development of plasmonic-mediated catalysis toward energy and environmental applications are discussed.

  19. Deformation-resembling microstructure created by fluid-mediated dissolution-precipitation reactions

    Spruzeniece, Liene; Piazolo, Sandra; Maynard-Casely, Helen E.


    Deformation microstructures are widely used for reconstructing tectono-metamorphic events recorded in rocks. In crustal settings deformation is often accompanied and/or succeeded by fluid infiltration and dissolution-precipitation reactions. However, the microstructural consequences of dissolution-precipitation in minerals have not been investigated experimentally. Here we conducted experiments where KBr crystals were reacted with a saturated KCl-H2O fluid. The results show that reaction products, formed in the absence of deformation, inherit the general crystallographic orientation from their parents, but also display a development of new microstructures that are typical in deformed minerals, such as apparent bending of crystal lattices and new subgrain domains, separated by low-angle and, in some cases, high-angle boundaries. Our work suggests that fluid-mediated dissolution-precipitation reactions can lead to a development of potentially misleading microstructures. We propose a set of criteria that may help in distinguishing such microstructures from the ones that are created by crystal-plastic deformation.

  20. Target-specific variants of Flp recombinase mediate genome engineering reactions in mammalian cells.

    Shah, Riddhi; Li, Feng; Voziyanova, Eugenia; Voziyanov, Yuri


    Genome engineering relies on DNA-modifying enzymes that are able to locate a DNA sequence of interest and initiate a desired genome rearrangement. Currently, the field predominantly utilizes site-specific DNA nucleases that depend on the host DNA repair machinery to complete a genome modification task. We show here that genome engineering approaches that employ target-specific variants of the self-sufficient, versatile site-specific DNA recombinase Flp can be developed into promising alternatives. We demonstrate that the Flp variant evolved to recombine an FRT-like sequence, FL-IL10A, which is located upstream of the human interleukin-10 gene, and can target this sequence in the model setting of Chinese hamster ovary and human embryonic kidney 293 cells. This target-specific Flp variant is able to perform the integration reaction and, when paired with another recombinase, the dual recombinase-mediated cassette exchange reaction. The efficiency of the integration reaction in human cells can be enhanced by 'humanizing' the Flp variant gene and by adding the nuclear localization sequence to the recombinase.

  1. immunologically mediated transfusional reactions Reacciones transfusionales mediadas inmunológicamente

    Elkín Ferdinand Cardona Duque


    Full Text Available The potential complications of blood transfusion therapy are multiple but most of them occur only in patients requiring repeated transfusions. Risks associated with transfusion of a single unit of blood are low; however, they must be weighted against the benefits at the time each transfusion is ordered. Transfusion reactions can be classified as either immunologic or non-immunologic. Many immune reactions are caused by stimulation of antibody production by foreign alloantigens present on transfused red cells, leukocytes, platelets, or plasma proteins. Such alloimmunization may lead to future immunologically mediated reactions when transfusions carrying these antigens are administered. These include hemolytic reactions caused by red blood cell incompatibility; febrile or pulmonary reactions caused by leukocytes and platelet antigens; allergic or anaphylactic reactions caused by antibodies reacting with soluble antigens, usually plasma proteins, and other reactions of lesser importance. Son muchas las complicaciones potenciales de la terapia transfusional, pero la mayoría se presentan en pacientes que requieren múltiples transfusiones. Los riesgos asociados con la transfusión de una unidad sanguínea son realmente bajos pero deben considerarse contra los beneficios que se buscan al ordenarla. Las reacciones transfusionales se pueden clasificar como inmunológicas y no inmunológicas. Muchas de las primeras son causadas por estimulación de los anticuerpos por parte de los antígenos presentes en la transfusión de glóbulos rojos, leucocitos, plaquetas o proteínas del plasma. Esa isoinmunización puede llevar a una reacción futura cuando dichos antígenos sean transfundidos nuevamente al paciente. Entre las posibilidades se incluyen la hemólisis por incompatibilidad; las reacciones febriles o pulmonares causadas por antígenos en las plaquetas o los leucocitos; los fenómenos alérgicos o anafilácticos debidos a anticuerpos que reaccionan

  2. SnCl2/Cu-Mediated Carbonyl Allylation Reaction in Water:Scope,Selectivity and Mechanism

    TAN,Xiang-Hui(谭翔晖); HOU,Yong-Quan(侯永泉); LIU,Lei(刘磊); GUO,Qing-Xiang(郭庆祥)


    Copper was found to be able to promote the SnC12-mediated carbonyl allylation reactions in water,giving the corresponding homoallylic alcohol products in very high yields.Detailed studies showed that the reaction could be applied to a variety of carbonyl compounds including those with hydroxyl,amino and nitro groups.It was also found that this reaction showed good regioselectivities for some substrates.Furthermore,carefully controled experiments and in situ NMR measurements provided important insights into the mechanism of the newly developed reaction.

  3. Water mediated hydrogen abstraction mechanism in the radical reaction between HOSO and NO2

    Lesar, Antonija; Tušar, Simona


    The effect of water molecules on the direct hydrogen abstraction from HOSO by NO2 was investigated for the first time. Stationary points were located at the B3LYP/6-311+G(2df,2pd) and CCSD/aug-cc-pVDZ levels of theory whereas energetics was further improved by CBS-QB3 and G4 composite methods. The fractions of hydrated radical complexes were estimated in order to assess atmospheric relevance of the title reaction. The energy barrier of the water mediated process becomes negligible. The formations of post-reactive complexes from pre-reactive complexes are energetically very favorable and the processes are spontaneous suggesting that they should be very feasible under atmospheric conditions.

  4. NMR measurement of hydrodynamic dispersion in porous media subject to biofilm mediated precipitation reactions.

    Fridjonsson, Einar O; Seymour, Joseph D; Schultz, Logan N; Gerlach, Robin; Cunningham, Alfred B; Codd, Sarah L


    Noninvasive measurements of hydrodynamic dispersion by nuclear magnetic resonance (NMR) are made in a model porous system before and after a biologically mediated precipitation reaction. Traditional magnetic resonance imaging (MRI) was unable to detect the small scale changes in pore structure visualized during light microscopy analysis after destructive sampling of the porous medium. However, pulse gradient spin echo nuclear magnetic resonance (PGSE NMR) measurements clearly indicated a change in hydrodynamics including increased pore scale mixing. These changes were detected through time-dependent measurement of the propagator by PGSE NMR. The dynamics indicate an increased pore scale mixing which alters the preasymptotic approach to asymptotic Gaussian dynamics governed by the advection diffusion equation. The methods described here can be used in the future to directly measure the transport of solutes in biomineral-affected porous media and contribute towards reactive transport models, which take into account the influence of pore scale changes in hydrodynamics.




    Objective: To develop a method to detect acrosome-reacted spermatozoa on human zonae pellucidae using only commercially available reagents and without need for sperm fixation. Design: Sperm head labeling with biotinylated soybean trypsin inhibitor (SBTI-biotin) was compared with results of a known m

  6. Effects of light energy and reducing agents on C60-mediated photosensitizing reactions.

    Quinones, Michael; Zhang, Yazhou; Riascos, Penelope; Hwang, Huey-Min; Aker, Winfred G; He, Xiaojia; Gao, Ruomei


    Many biomolecules contain photoactive reducing agents, such as reduced nicotinamide adenine dinucleotide (NADH) and 6-thioguanine (6-TG) incorporated into DNA through drug metabolism. These reducing agents may produce reactive oxygen species under UVA irradiation or act as electron donors in various media. The interactions of C60 fullerenes with biological reductants and light energy, especially via the Type-I electron-transfer mechanism, are not fully understood although these factors are often involved in toxicity assessments. The two reductants employed in this work were NADH for aqueous solutions and 6-TG for organic solvents. Using steady-state photolysis and electrochemical techniques, we showed that under visible light irradiation, the presence of reducing agents enhanced C60 -mediated Type-I reactions that generate superoxide anion (O2(.-)) at the expense of singlet oxygen ((1)O2) production. The quantum yield of O2(.-) production upon visible light irradiation of C60 is estimated below 0.2 in dipolar aprotic media, indicating that the majority of triplet C60 deactivate via Type-II pathway. Upon UVA irradiation, however, both C60 and NADH undergo photochemical reactions to produce O2(.-), which could lead to a possible synergistic toxicity effects. C60 photosensitization via Type-I pathway is not observed in the absence of reducing agents. © 2013 The American Society of Photobiology.

  7. Hapten-Induced Contact Hypersensitivity, Autoimmune Reactions, and Tumor Regression: Plausibility of Mediating Antitumor Immunity

    Dan A. Erkes


    Full Text Available Haptens are small molecule irritants that bind to proteins and elicit an immune response. Haptens have been commonly used to study allergic contact dermatitis (ACD using animal contact hypersensitivity (CHS models. However, extensive research into contact hypersensitivity has offered a confusing and intriguing mechanism of allergic reactions occurring in the skin. The abilities of haptens to induce such reactions have been frequently utilized to study the mechanisms of inflammatory bowel disease (IBD to induce autoimmune-like responses such as autoimmune hemolytic anemia and to elicit viral wart and tumor regression. Hapten-induced tumor regression has been studied since the mid-1900s and relies on four major concepts: (1 ex vivo haptenation, (2 in situ haptenation, (3 epifocal hapten application, and (4 antigen-hapten conjugate injection. Each of these approaches elicits unique responses in mice and humans. The present review attempts to provide a critical appraisal of the hapten-mediated tumor treatments and offers insights for future development of the field.

  8. Visible-Light-Irradiated Graphitic Carbon Nitride Photocatalyzed Diels-Alder Reactions with Dioxygen as Sustainable Mediator for Photoinduced Electrons.

    Zhao, Yubao; Antonietti, Markus


    Photocatalytic Diels-Alder (D-A) reactions with electron rich olefins are realized by graphitic carbon nitride (g-C3 N4 ) under visible-light irradiation and aerobic conditions. This heterogeneous photoredox reaction system is highly efficient, and the apparent quantum yield reaches a remarkable value of 47 % for the model reaction. Dioxygen plays a critical role as electron mediator, which is distinct from the previous reports in the homogeneous Ru(II) complex photoredox system. Moreover, the reaction intermediate vinylcyclobutane is captured and monitored during the reaction, serving as a direct evidence for the proposed reaction mechanism. The cycloaddition process is thereby determined to be the combination of direct [4+2] cycloaddition and [2+2] cycloaddition followed by photocatalytic rearrangement of the vinylcyclobutane intermediate. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Palladium- and copper-mediated N-aryl bond formation reactions for the synthesis of biological active compounds

    Burkhard Koenig


    Full Text Available N-Arylated aliphatic and aromatic amines are important substituents in many biologically active compounds. In the last few years, transition-metal-mediated N-aryl bond formation has become a standard procedure for the introduction of amines into aromatic systems. While N-arylation of simple aromatic halides by simple amines works with many of the described methods in high yield, the reactions may require detailed optimization if applied to the synthesis of complex molecules with additional functional groups, such as natural products or drugs. We discuss and compare in this review the three main N-arylation methods in their application to the synthesis of biologically active compounds: Palladium-catalysed Buchwald–Hartwig-type reactions, copper-mediated Ullmann-type and Chan–Lam-type N-arylation reactions. The discussed examples show that palladium-catalysed reactions are favoured for large-scale applications and tolerate sterically demanding substituents on the coupling partners better than Chan–Lam reactions. Chan–Lam N-arylations are particularly mild and do not require additional ligands, which facilitates the work-up. However, reaction times can be very long. Ullmann- and Buchwald–Hartwig-type methods have been used in intramolecular reactions, giving access to complex ring structures. All three N-arylation methods have specific advantages and disadvantages that should be considered when selecting the reaction conditions for a desired C–N bond formation in the course of a total synthesis or drug synthesis.

  10. Kinetics of microbially mediated reactions: dissimilatory sulfate reduction in saltmarsh sediments (Sapelo Island, Georgia, USA)

    Roychoudhury, Alakendra N.; Van Cappellen, Philippe; Kostka, Joel E.; Viollier, Eric


    A sediment disk reactor was tested in once flow-through mode to retrieve kinetic parameters for the Monod rate law that describes sulfate reduction. The experimental method was compared with a previously described procedure by the authors where a sediment plug-flow reactor was operated in a recirculation mode. In recirculation mode, accumulation of metabolic byproducts in certain cases may result in negative feedback, thus preventing accurate determination of kinetic information. The method described in this article provides an alternative to the recirculation sediment plug-flow-through reactor technique for retrieving kinetic parameters of microbially mediated reactions in aquatic sediments. For sulfate reduction in a saltmarsh site, a maximum estimate of the half-saturation concentration, Ks, of 204±26 μM and a maximum reaction rate, Rm, of 2846±129 nmol cm( wet sediment ) 3 d-1 was determined. The Ks value obtained was consistent with the one estimated previously (K s=240±20 μM) from a different site within the same saltmarsh mud flat using a recirculating reactor. From the Rm value and reduction rates determined using 35SO 42- incubation experiments, we infer that sulfate reduction is limited in the field. Substrate availability is not the main contributor for the limitation, however. Competition from other microbes, such as iron reducers affects the activity of sulfate reducers in the suboxic to anoxic zones, whereas aerobes compete in the oxic zone. High sulfide concentration in the pore water may also have acted as a toxin to the sulfate reducers in the field.

  11. The pivotal role of fibrocytes and mast cells in mediating fibrotic reactions to biomaterials.

    Thevenot, Paul T; Baker, David W; Weng, Hong; Sun, Man-Wu; Tang, Liping


    Almost all biomaterial implants are surrounded by a fibrotic capsule, although the mechanism of biomaterial-mediated fibrotic reactions is mostly unclear. To search for the types of cells responsible for triggering the tissue responses, we used poly-L glycolic acid polymers capable of releasing various reagents. We first identified that CD45(+)/Collagen 1(+) fibrocytes are recruited and resided within the fibrotic capsule at the implant interface. Interestingly, we found that the recruitment of fibrocytes and the extent of fibrotic tissue formation (collagen type I production) were substantially enhanced and reduced by the localized release of compound 48/80 and cromolyn, respectively. Since it is well established that compound 48/80 and cromolyn alter mast cell reactions, we hypothesized that mast cells are responsible for triggering fibrocyte recruitment and subsequent fibrotic capsule formation surrounding biomaterial implants. To directly test this hypothesis, similar studies were carried out using mast cell deficient mice, WBB6F1/J-Kit(W)/Kit(W-v)/, and their congenic controls. Indeed, mast cell deficient mice prompted substantially less fibrocyte and myofibroblast responses in comparison to C57 wild type mice controls. Most interestingly, subcutaneous mast cell reconstitution of WBB6F1/J-Kit(W)/Kit(W-v)/J mice almost completely restored the fibrocyte response in comparison to the C57 wild type response. These results indicate that the initial biomaterial interaction resulting in the stimulation of mast cells and degranulation byproducts not only stimulates the inflammatory cascade but significantly alters the downstream fibrocyte response and degree of fibrosis.

  12. Ion-Mediated Polymerase Chain Reactions Performed with an Electronically Driven Microfluidic Device.

    Zhang, Yi; Li, Qian; Guo, Linjie; Huang, Qing; Shi, Jiye; Yang, Yang; Liu, Dongsheng; Fan, Chunhai


    The polymerase chain reaction (PCR) is a powerful method for exponentially amplifying very low amounts of target DNA from genetic, clinical, and forensic samples. However, the heating and cooling steps in PCR largely hamper the miniaturization of thermocyclers for on-site detection of pathogens and point-of-care tests. Herein, we devise an ion-mediated PCR (IM-PCR) strategy by exploiting ion-induced DNA denaturation/renaturation cycles. DNA duplexes are effectively denatured in alkaline solutions; whereas, the denatured single-stranded DNA strands readily reform duplexes at neutral pH. By using an integrated microchip that can programmably control the solution pH simply switching the potential in a range of several hundred millivolts, we can trigger IM-PCR at a constant temperature. Analogously to thermal cycling, 30 cycles of pH-induced denaturation/renaturation were used to amplify protein DNA fragments as confirmed by DNA sequencing. We anticipate that this portable, low-cost, and scalable IM-PCR holds great promise for widespread biological, clinical, and environmental applications.

  13. Spermatogenesis of the green-lipped mussel Perna viridis with dual patterns of acrosome and tail development in spermatids

    Reunov, A. A.; Au, D. W. T.; Wu, R. S. S.


    Spermatogenesis in the mussel Perna viridis was studied by electron microscopy. Results demonstrated that cytological development in spermatogonia and spermatocytes was similar to that previously described in other Mytilidae. Acrosome formation began with the arising of proacrosomal vesicles in spermatogonia. The abundance of proacrosomal vesicles increased in spermatocytes, which were flagellated. However, during spermiogenesis, dual patterns of acrosome development as well as flagellum development could be found among spermatids in a male gonad. The two lines of acrosome formation in spermatids ultimately gave rise to morphologically similar acrosomes. The two lines of flagellum development in spermatids resulted in the formation of sperm cells with either a typically posteriorly directed tail or an anteriorly directed tail.

  14. Validation of the polysemen admixture on viability and acrosomal morphology of boar spermatozoa

    Ogbuewu IP


    Full Text Available Semen were collected using artificial vagina (AV, from 5 large white boars aged 2-2.5 years twice a week for 16 weeks in each of the two seasons, early rainy (ER and late rainy (LR seasons, to determine the effects of multiple semen pool admixture on the viability and acrosomal morphology. The semen qualities studied were sperm motility, live sperm and sperm concentration, while the acrosomal parameters includes normal apical ridge (NAR, damaged apical ridge (DAR, missing apical ridge (MAR and loose apical ridge (LAC. There were no significant (P>0.05 seasonal effects. Three-boar semen admixture gave the highest percentage NAR, motility, live sperm concentration and least DAR and LAC, although these were not significantly (P>0.05 different from the 2-boar semen admixture. The result of this study suggests that 3-boar semen admixture is most suitable for use in artificial insemination program.

  15. Effects of acrosomal conditions of frozen-thawed spermatozoa on the results of artificial insemination in Japanese Black cattle.

    Kishida, Kazumi; Sakase, Mitsuhiro; Minami, Kenta; Arai, Miyuki M; Syoji, Reiko; Kohama, Namiko; Akiyama, Takayuki; Oka, Akio; Harayama, Hiroshi; Fukushima, Moriyuki


    The purposes of this study were to examine the relationship between male artificial insemination (AI) fertility and sperm acrosomal conditions assessed by new and conventional staining techniques and to identify possible reproductive dysfunctions causing low conception rates in AI using frozen-thawed spermatozoa with poor acrosomal conditions in Japanese Black bulls. We investigated individual differences among bulls in the results concerning (1) acrosomal conditions of frozen-thawed spermatozoa as assessed by not merely peanut agglutinin-lectin staining (a conventional staining technique) but also immunostaining of acrosomal tyrosine-phosphorylated proteins (a new staining technique), (2) routine AI using frozen-thawed spermatozoa as assessed by pregnancy diagnosis, (3) in vivo fertilization of frozen-thawed spermatozoa and early development of fertilized eggs as assessed by superovulation/AI-embryo collection tests and (4) in vitro fertilization of frozen-thawed spermatozoa with oocytes. The percentages of frozen-thawed spermatozoa with normal acrosomal conditions assessed by the abovementioned staining techniques were significantly correlated with the conception rates of routine AI, rates of transferable embryos in superovulation/AI-embryo collection tests and in vitro fertilization rates. These results are consistent with new suggestions that the distribution of acrosomal tyrosine-phosphorylated proteins as well as the acrosomal morphology of frozen-thawed spermatozoa are AI fertility-associated markers that are valid for the prediction of AI results and that low conception rates in AI using frozen-thawed spermatozoa with poor acrosomal conditions result from reproductive dysfunctions in the processes between sperm insemination into females and early embryo development, probably failed fertilization of frozen-thawed spermatozoa with oocytes.

  16. Emotional Reactions Mediate the Effect of Music Listening on Creative Thinking: Perspective of the Arousal-and-Mood Hypothesis

    Wu-Jing He


    Full Text Available This study examined the effect of music listening on creative thinking through the lens of the arousal-and-mood hypothesis, which posits that emotional reactions (i.e., arousal and valence mediate the effect of music listening on cognitive functioning. Participants were randomly assigned to three groups: a positive music group (n = 198, a negative music group (n = 195, and a control group (n = 191. Creative thinking and emotional reactions were assessed with the Test for Creative Thinking-Drawing Production and the Affect Grid, respectively. The results showed that both positively and negatively arousing music enhanced creative thinking. The results further revealed that arousal, regardless of valence, significantly mediated the music-creativity relationship. This study enriches the research on the arousal-and-mood hypothesis by (1 providing direct empirical testing on the mediating roles of emotional reactions; (2 including both positively and negatively arousing music in the study design; and (3 identifying that only arousal, and not valence, was a significant mediator in the music-creativity link.

  17. IgE- and IgG mediated severe anaphylactic platelet transfusion reaction in a known case of cerebral malaria

    B Shanthi


    Full Text Available Background: Allergic reactions occur commonly in transfusion practice. However, severe anaphylactic reactions are rare; anti-IgA (IgA: Immunoglobulin A in IgA-deficient patients is one of the well-illustrated and reported causes for such reactions. However, IgE-mediated hypersensitivity reaction through blood component transfusion may be caused in parasitic hyperimmunization for IgG and IgE antibodies. Case Report: We have evaluated here a severe anaphylactic transfusion reaction retrospectively in an 18year-old male, a known case of cerebral malaria, developed after platelet transfusions. The examination and investigations revealed classical signs and symptoms of anaphylaxis along with a significant rise in the serum IgE antibody level and IgG by hemagglutination method. Initial mild allergic reaction was followed by severe anaphylactic reaction after the second transfusion of platelets. Conclusion: Based on these results, screening of patients and donors with mild allergic reactions to IgE antibodies may help in understanding the pathogenesis as well as in planning for preventive desensitization and measures for safe transfusion.

  18. Effects of Sperm Acrosomal Integrity and Protamine Deficiency on In Vitro Fertilization and Pregnancy Rate

    Marziyeh Tavalaee


    Full Text Available Background: The objective of this study was to evaluate the relationship between protaminedeficiency, and acrosomal integrity with fertilization and pregnancy rate in patients undergone in vitrofertilization (IVF.Material &Methods: Semen samples from 70 infertile couples undergoing IVF at Isfahan Fertility andInfertility center were assessed in this study. Semen analysis was carried out according to WHO criteria.Protamine deficiency, Sperm morphology and acrosin activity were assessed by Chromomycin A3(CMA3, Papanicolaou staining and Gelatinolysis tests, respectively. Coefficients of correlation andstudent t-test were carried out using the Statistical Package for the Social Studies (SPSS 11.5 and Pvaluelower than 0.05 was considered as significant.Results: Fertilization rate, percentage of halo formation, mean halo diameter and abnormalmorphology show a significant correlation with percentage of CMA3 positivity. CMA3 positivity,percentage of halo, mean halo and sperm morphology showed a significant correlation with fertilizationrate. Among the aforementioned parameters percentage of halo had the highest correlation. In thepresent study patients were divided into two groups according to pregnancy status. None of the studiedparameters were significantly different between pregnant and non-pregnant patients. However,percentage of halo formation showed a slightly significant difference (r=0.306; P=0.058.Conclusion: The results of this study revealed that, even though sperm morphology, sperm protaminecontent and acrosome formation are events related to spermiogenesis, sperm acrosomal integrityassessed by percentage of halo formation has more profound effect on fertilization rate and pregnancyoutcome during IVF procedure.

  19. Acrosome membrane integrity and cryocapacitation are related to cholesterol content of bull spermatozoa

    Srivastava N; Srivastava SK; Ghosh SK; Amit Kumar; Perumal P; Jerome A


    Objective: To evaluate the cryoinjury prediction of spermatozoa in relation to its cholesterol content at fresh and frozen-thaw stages. Methods: Ejaculates (n=12) were processed for cryopreservation, acrosome integrity (fluorescent and giemsa stains), cryoinjury (distribution of non capacitated, capacitated and acrosome reacted, pattern F, B and AR, respectively of Chlortetracycline, CTC assay), in vitro fertiltiy (IVF) and cholesterol content of spermatozoa at fresh, pre-freeze and frozen-thaw stages were evaluated. Values were fitted in prediction equation to predict acrosome integrity (AI) and cryoinjury. Results: Study indicated that cholesterol content of fresh spermatozoa can be used to predict cholesterol content of spermatozoa at pre-freeze and frozen-thaw stages of cryopreservation protocol with medium to high level of accuracy (P<0.05 and P<0.01, respectively). Cholesterol content of fresh spermatozoa can be used to predict AI, pattern B and AR and Penetration Index (PI) of IVF with medium level of accuracy (P<0.05) at frozen-thaw but not at pre-freeze stage. Similarly cholesterol content of frozen-thaw spermatozoa can be used to predict AI and pattern AR of frozen-thaw spermatozoa with medium level of accuracy (P<0.05). Conclusion: This study revealed strong evidence that cholesterol content of fresh as well as frozen-thaw bull spermatozoa can be a good predictor of level of cryoinjury following preservation at ultra low temperature.

  20. Sirt1 regulates acrosome biogenesis by modulating autophagic flux during spermiogenesis in mice.

    Liu, Chao; Song, Zhenhua; Wang, Lina; Yu, Haiyan; Liu, Weixiao; Shang, Yongliang; Xu, Zhiliang; Zhao, Haichao; Gao, Fengyi; Wen, Jiamin; Zhao, Linan; Gui, Yaoting; Jiao, Jianwei; Gao, Fei; Li, Wei


    Sirt1 is a member of the sirtuin family of proteins and has important roles in numerous biological processes. Sirt1(-/-) mice display an increased frequency of abnormal spermatozoa, but the mechanism of Sirt1 in spermiogenesis remains largely unknown. Here, we report that Sirt1 might be directly involved in spermiogenesis in germ cells but not in steroidogenic cells. Germ cell-specific Sirt1 knockout mice were almost completely infertile; the early mitotic and meiotic progression of germ cells in spermatogenesis were not obviously affected after Sirt1 depletion, but subsequent spermiogenesis was disrupted by a defect in acrosome biogenesis, which resulted in a phenotype similar to that observed in human globozoospermia. In addition, LC3 and Atg7 deacetylation was disrupted in spermatids after knocking out Sirt1, which affected the redistribution of LC3 from the nucleus to the cytoplasm and the activation of autophagy. Furthermore, Sirt1 depletion resulted in the failure of LC3 to be recruited to Golgi apparatus-derived vesicles and in the failure of GOPC and PICK1 to be recruited to nucleus-associated acrosomal vesicles. Taken together, these findings reveal that Sirt1 has a novel physiological function in acrosome biogenesis. © 2017. Published by The Company of Biologists Ltd.

  1. Effect of cholesterol-loaded-cyclodextrin on sperm viability and acrosome reaction in boar semen cryopreservation.

    Lee, Yong-Seung; Lee, Seunghyung; Lee, Sang-Hee; Yang, Boo-Keun; Park, Choon-Keun


    This study was undertaken to examine the effect of cholesterol-loaded-cyclodextrin (CLC) on boar sperm viability and spermatozoa cryosurvival during boar semen cryopreservation, and methyl-β-cyclodextrin (MBCD) was treated for comparing with CLC. Boar semen treated with CLC and MBCD before freezing process to monitor the effect on survival and capacitation status by flow cytometry with appropriate fluorescent probes. Sperm viability was higher in 1.5mg CLC-treated sperm (76.9±1.01%, Psperm before cryopreservation (58.7±1.31% and 60.3±0.31%, respectively). For CTC patterns, F-pattern was higher in CLC treated sperm than MBCD-treated sperm, for B-pattern was higher in CLC-treated sperm than fresh sperm (Psperm) was lower in CLC-treated sperm than MBCD-treated sperm (Pboar semen.




    The fusogenic properties of bovine and human spermatozoa membranes were investigated, using phospholipid bilayers (liposomes) as target membranes. Fusion was monitored by following lipid mixing, as revealed by an assay based on resonance-energy transfer. In addition, fusion was visualized by fluores

  3. Seipin deficiency increases chromocenter fragmentation and disrupts acrosome formation leading to male infertility.

    El Zowalaty, A E; Baumann, C; Li, R; Chen, W; De La Fuente, R; Ye, X


    The Berardinelli-Seip congenital lipodystrophy type 2 (Bscl2, seipin) gene is involved in adipogenesis. Bscl2-/- males were infertile but had normal mating behavior. Both Bscl2-/- cauda epididymis sperm count and sperm motility were ~20×less than control. Bscl2-/- seminiferous tubules had relatively normal presence of spermatogonia and spermatocytes but had reduced spermatids and sperm. Spatiotemporal expression analyses in Bscl2+/+ testes demonstrated prominent Bscl2 transcriptional activity in spermatocytes with a plateau reached around postnatal day 28. Seipin protein localization was most abundant in postmeiotic spermatids, suggesting translational repression of Bscl2 mRNA in spermatocytes. In situ end-labeling plus detected increased spermatid apoptosis in Bscl2-/- testis and annexin V detected increased percentage of positive Bscl2-/- round spermatids compared with control. Immunofluorescence of marker proteins synaptonemal complex proteins 3 and 1 (SYCP3 and SYCP1), and H3K9me3 (histone H3 trimethylated at lysine 9) in germ cell spreads detected normal meiotic chromosome pairing and homologous chromosome synapsis in Bscl2-/- spermatocytes, but significantly increased percentages of round spermatids with chromocenter fragmentation and late spermatids and sperm with chromatin vacuoles, indicating defective chromatin condensation in Bscl2-/- spermatids. Bscl2-/- late spermatids were disorganized within the seminiferous epithelium, despite normal appearance of Sertoli cells detected by vimentin immunofluorescence. Peanut agglutinin staining revealed various abnormalities of acrosomes in Bscl2-/- late spermatids, including the absence, irregular-shaped, and fragmented acrosomes, indicating defective acrosome formation in Bscl2-/- late spermatids, which may affect late spermatid orientation in the seminiferous epithelium. Mitotracker strongly stained the midpiece of control sperm but only very weakly labeled the midpiece of Bscl2-/- sperm, indicating defective

  4. Sm/TiCl4 (cat.) system-mediated intermolecular and intramolecular reductive coupling reactions of ketones with esters

    LIU Yun-kui; XU Dan-qian; XU Zhen-yuan; ZHANG Yong-min


    Sm/TiCl4 system could well integrate the high reactivity of samarium(Ⅱ) and high deoxygenation capacity of low valent titanium within one system. In this paper, the intermolecular and intramolecular reductive coupling reactions of ketones with esters mediated by metallic samarium (Sm) and a catalytic amount of titanium tetrachloride (TiCl4) were successfully developed. A series of substituted ketones and cyclic β-keto-esters were prepared in moderate to good yields under reflux and neutral conditions.

  5. A route to hydroxylfluorenes: TsOH-mediated condensation reactions of 1,3-diketones with propargylic alcohols

    Yao, Liangfeng


    An efficient method of preparing hydroxylfluorenes by TsOH-mediated tandem alkylation/rearrangements of propargylic alcohols with 1,3-diketones is described. These reactions are accomplished in moderate to good yields under mild conditions to offer a straightforward and convenient one step synthetic route to hydroxylfluorene derivatives through a plausible mechanism involving a sequence of dehydration, addition, rearrangement and aromatization. This journal is © The Royal Society of Chemistry 2012.

  6. Diet-Induced Obesity Enhances TRPV1-Mediated Neurovascular Reactions in the Dura Mater.

    Marics, Balázs; Peitl, Barna; Pázmándi, Kitti; Bácsi, Attila; Németh, József; Oszlács, Orsolya; Jancsó, Gábor; Dux, Mária


    -induced CGRP release from meningeal afferents ex vivo. Except for minor morphological changes, the distribution of dural TRPV1- and CGRP-immunoreactive afferents was similar in control and obese animals. Our results suggest that obesity induced by long-term HFHS diet results in sensitization of the trigeminovascular system. Changes in TRPV1-mediated vascular reactions and CGRP release are pathophysiological alterations that may be of relevance to the enhanced headache susceptibility of obese individuals. © 2017 American Headache Society.

  7. Social Reactions to Sexual Assault Disclosure and Problem Drinking: Mediating Effects of Perceived Control and PTSD

    Peter-Hagene, Liana C.; Ullman, Sarah E.


    Sexual assault survivors receive various positive and negative social reactions to assault disclosures, yet little is known about mechanisms linking these social reactions to posttraumatic stress disorder (PTSD) symptoms and problem drinking. Data from a large, diverse sample of women who had experienced adult sexual assault was analyzed with structural equation modeling to test a theoretical model of the relationships between specific negative social reactions (e.g., controlling, infantilizi...

  8. Zona Pellucida Induces Activation of Phospholipase A2 During Acrosomal Exocytosis in Guinea PigSpermatozoa

    袁玉英; 陈文颖; 石其贤; 毛丽珍; 俞淑清; 方昕; E.R.S.Roldan


    Objective To investigate whether PLA2 is involved in ZP-stimulated acrosomal exocytosis,if Ca2+ is required for activation of PLA2,and sigal transduction pathways modulating PLA2. Methods Guinea-pig spermatozoa were capacitated and labeled in low Ca2+ medium with [14C]choline chloride or [14C] arachidonic acid,and were then exposed to millimolar Ca2+ and various reagents and stimulated with ZP. Results Precapacitated spermatozoa exposed to millimolar Ca2+ and stimulated with ZP experienced increases in arachidonic acid(AA)and lysophosphatidylcholine (lysoPC) and a parallel decrease in phosphatidylcholine (PC);these chages are indicative of PLA2 activation.Simulation with ZP also led to acrosomal exocytosis in a high proportion of spermatozoa. Lipid changes and exocytosis were prevented if spermatozoa were exposed to aristolochic acid,a PLA2 inhibitor, before treatment with ZP.Stimulation with ZP in medium without added Ca2+,or in medium with millimolar Ca2+ and EGTA or La3+ resulted in no lipid changes or exocytosis. Pretreatment with pertussis toxin,a G1 protein inhibitor, before stimulation with ZP,blocked the release of AA and lysoPC and acrosomal exocytosis.Exposure of spermatozoa to the DAG kinase inhibitor R59022 before ZP stimulation led to a significant increase in the generation of lysoPC and exocytosis.Conclusion These results indicate very strongly that PLA2 plays an essential role in ZP-induced exocytosis in spermatozoa, that PLA2 activation requires Ca2+ internalization,and that it is regulated by signal transduction pathways involving G proteins and DAG.

  9. Real-time electrochemical monitoring of the polymerase chain reaction by mediated redox catalysis.

    Deféver, Thibaut; Druet, Michel; Rochelet-Dequaire, Murielle; Joannes, Martine; Grossiord, Céline; Limoges, Benoit; Marchal, Damien


    We described the proof-of-principle of a nonoptical real-time PCR that uses cyclic voltammetry for indirectly monitoring the amplified DNA product generated in the PCR reaction solution after each PCR cycle. To enable indirect measurement of the amplicon produced throughout PCR, we monitor electrochemically the progressive consumption (i.e., the decrease of concentration) of free electroactive deoxynucleoside triphosphates (dNTPs) used for DNA synthesis. This is accomplished by exploiting the fast catalytic oxidation of native deoxyguanosine triphosphate (dGTP) or its unnatural analogue 7-deaza-dGTP by the one-electron redox catalysts Ru(bpy)(3)(3+) (with bpy = 2,2'-bipyridine) or Os(bpy)(3)(3+) generated at an electrode. To demonstrate the feasibility of the method, a disposable array of eight miniaturized self-contained electrochemical cells (working volume of 50 microL) has been developed and implemented in a classical programmable thermal cycler and then tested with the PCR amplification of two illustrated examples of real-world biological target DNA sequences (i.e., a relatively long 2300-bp sequence from the bacterial genome of multidrug-resistant Achromobacter xylosoxidans and a shorter 283-bp target from the human cytomegalovirus). Although the method works with both mediator/base couples, the catalytic peak current responses recorded with the Ru(bpy)(3)(3+)/dGTP couple under real-time PCR conditions are significantly affected by a continuous current drift and interference with the background solvent discharge, thus leading to poorly reproducible data. Much more reproducible and reliable results are finally obtained with the Os(bpy)(3)(3+)/7-deaza-dGTP, a result that is attributed to the much lower anodic potential at which the catalytic oxidation of 7-deaza-dGTP by Os(bpy)(3)(3+) is detected. Under these conditions, an exponential decrease of the catalytic signal as a function of the number of PCR cycles is obtained, allowing definition of a cycle

  10. Pyrovanadolysis: a Pyrophosphorolysis-like Reaction Mediated by Pyrovanadate MN2plus and DNA Polymerase of Bacteriophage T7

    B Akabayov; A Kulczyk; S Akabayov; C Thiele; L McLaughlin; B Beauchamp; C Richardson


    DNA polymerases catalyze the 3'-5'-pyrophosphorolysis of a DNA primer annealed to a DNA template in the presence of pyrophosphate (PP{sub i}). In this reversal of the polymerization reaction, deoxynucleotides in DNA are converted to deoxynucleoside 5'-triphosphates. Based on the charge, size, and geometry of the oxygen connecting the two phosphorus atoms of PP{sub i}, a variety of compounds was examined for their ability to carry out a reaction similar to pyrophosphorolysis. We describe a manganese-mediated pyrophosphorolysis-like activity using pyrovanadate (VV) catalyzed by the DNA polymerase of bacteriophage T7. We designate this reaction pyrovanadolysis. X-ray absorption spectroscopy reveals a shorter Mn-V distance of the polymerase-VV complex than the Mn-P distance of the polymerase-PP{sub i} complex. This structural arrangement at the active site accounts for the enzymatic activation by Mn-VV. We propose that the Mn{sup 2+}, larger than Mg{sup 2+}, fits the polymerase active site to mediate binding of VV into the active site of the polymerase. Our results may be the first documentation that vanadium can substitute for phosphorus in biological processes.

  11. Stereoselective titanium-mediated aldol reactions of a chiral lactate-derived ethyl ketone with ketones.

    Alcoberro, Sandra; Gómez-Palomino, Alejandro; Solà, Ricard; Romea, Pedro; Urpí, Fèlix; Font-Bardia, Mercè


    Aldol reactions of titanium enolates of lactate-derived ethyl ketone 1 with other ketones proceed in a very efficient and stereocontrolled manner provided that a further equivalent of TiCl4 is added to the reacting mixture. The scope of these reactions encompasses simple ketones such as acetone or cyclohexanone as well as other ketones that contain potential chelating groups such as pyruvate esters or α- and β-hydroxy ketones.

  12. Cu-Mediated Stille Reactions of Sterically Congested Fragments: Towards the Total Synthesis of Zoanthamine

    Nielsen, Thomas E.; Le Quement, Sebastian; Juhl, Martin;


    A study on the Stille reaction of alkenyl iodides and starmanes with structural resemblance to retrosynthetic fragments of a projected total synthesis of the marine alkaloid zoanthamine was carried out. A range of reaction conditions was examined, and a protocol developed by Corey utilizing excess...... copper(I) chloride and lithium chloride was found to be most efficient. The methodology was successfully applied to join two major fragments of the zoanthamine skeleton. (c) 2005 Elsevier Ltd. All rights reserved....

  13. Tri-n-butylphosphine Mediated Ring-Opening Reactions of Aziridines or Epoxides with Diphenyl Diselenide

    ZHANG Wan-Xuan; YE Kang; RUAN Shan; CHEN Zu-Xing; XIA Qing-Hua


    Aziridines and epoxides were reacted with diphenyl diselenide in the presence of a stoichiometric amount of (n-Bu)3P, respectively, giving β-amino-or β-hydroxy selenides in moderate to excellent yields under mild conditions. In the reactions the (n-Bu)3P might act as a reductant though it was a nucleophilic catalyst in other similar ring-opening reactions.

  14. immunologically mediated transfusional reactions Reacciones transfusionales mediadas inmunológicamente

    Elkín Ferdinand Cardona Duque


    The potential complications of blood transfusion therapy are multiple but most of them occur only in patients requiring repeated transfusions. Risks associated with transfusion of a single unit of blood are low; however, they must be weighted against the benefits at the time each transfusion is ordered. Transfusion reactions can be classified as either immunologic or non-immunologic. Many immune reactions are caused by stimulation of antibody production by foreign alloantigens present on tran...

  15. Microwave-Mediated Hetero Diels-Alder reaction: Synthesis of biologically active compounds

    D’Aurizio, Antonio


    Heterocyclic compounds represent almost two-thirds of all the known organic compounds: they are widely distributed in nature and play a key role in a huge number of biologically important molecules including some of the most significant for human beings. A powerful tool for the synthesis of such compounds is the hetero Diels-Alder reaction (HDA), that involve a [4+2] cycloaddition reaction between heterodienes and suitable dienophiles. Among heterodienes to be used in such six-membered ...

  16. Anxiety sensitivity and post-traumatic stress reactions: Evidence for intrusions and physiological arousal as mediating and moderating mechanisms.

    Olatunji, Bunmi O; Fan, Qianqian


    A growing body of research has implicated anxiety sensitivity (AS) and its dimensions in the development of post-traumatic stress disorder (PTSD). However, the mechanism(s) that may account for the association between AS and PTSD remains unclear. Using the "trauma film paradigm," which provides a prospective experimental tool for investigating analog intrusion development, the present study examines the extent to which intrusions mediate the association between AS and the development of posttraumatic stress reactions. After completing a measure of AS and state mood, unselected participants (n = 45) viewed a 10 min film of graphic scenes of fatal traffic accidents and then completed a second assessment of state mood. Participants then kept a daily diary to record intrusions about the film for a one-week period. Post-traumatic stress reactions about the film were then assessed after the one-week period. The results showed that general AS and physical and cognitive concerns AS predicted greater post-traumatic stress reactions about the film a week later. Furthermore, the number of intrusions the day after viewing the traumatic film, but not fear and disgust in response to the trauma film, mediated the association between general AS (and AS specifically for physical and cognitive concerns) and post-traumatic stress reactions a week later. Subsequent analysis also showed that physiological arousal during initial exposure to the traumatic film moderated the association between general AS and the number of intrusions reported the day after viewing the film. The implications of these analog findings for conceptualizing the mechanism(s) that may interact to explain the role of AS in the development of PTSD and its effective treatment are discussed.

  17. Links between Adolescents' Expected Parental Reactions and Prosocial Behavioral Tendencies: The Mediating Role of Prosocial Values

    Hardy, Sam A.; Carlo, Gustavo; Roesch, Scott C.


    The purpose of the present study was to examine relations between adolescents' social cognitions regarding parenting practices and adolescents' prosocial behavioral tendencies. A mediation model was tested whereby the degree to which adolescents perceived their parents as responding appropriately to their prosocial and antisocial behaviors was…

  18. Discrimination of Arcobacter butzleri isolates by polymerase chain reaction-mediated DNA fingerprinting

    Atabay, H. I.; Bang, Dang Duong; Aydin, F.;


    Aims: The objective of this study was to subtype Arcobacter butzleri isolates using RAPD-PCR. Methods and Results: Thirty-five A. butzleri isolates obtained from chicken carcasses were examined. PCR-mediated DNA fingerprinting technique with primers of the variable sequence motifs was used...

  19. Plasma contact system activation drives anaphylaxis in severe mast cell-mediated allergic reactions

    Sala-Cunill, Anna; Björkqvist, Jenny; Senter, Riccardo; Guilarte, Mar; Cardona, Victoria; Labrador, Moises; Nickel, Katrin F; Butler, Lynn; Luengo, Olga; Kumar, Parvin; Labberton, Linda; Long, Andy; Di Gennaro, Antonio; Kenne, Ellinor; Jämsä, Anne; Krieger, Thorsten; Schlüter, Hartmut; Fuchs, Tobias; Flohr, Stefanie; Hassiepen, Ulrich; Cumin, Frederic; McCrae, Keith; Maas, Coen; Stavrou, Evi; Renné, Thomas


    BACKGROUND: Anaphylaxis is an acute, potentially lethal, multisystem syndrome resulting from the sudden release of mast cell-derived mediators into the circulation. OBJECTIVES AND METHODS: We report here that a plasma protease cascade, the factor XII-driven contact system, critically contributes to

  20. Controlling Solution-Mediated Reaction Mechanisms of Oxygen Reduction Using Potential and Solvent for Aprotic Lithium-Oxygen Batteries.

    Kwabi, David G; Tułodziecki, Michał; Pour, Nir; Itkis, Daniil M; Thompson, Carl V; Shao-Horn, Yang


    Fundamental understanding of growth mechanisms of Li2O2 in Li-O2 cells is critical for implementing batteries with high gravimetric energies. Li2O2 growth can occur first by 1e(-) transfer to O2, forming Li(+)-O2(-) and then either chemical disproportionation of Li(+)-O2(-), or a second electron transfer to Li(+)-O2(-). We demonstrate that Li2O2 growth is governed primarily by disproportionation of Li(+)-O2(-) at low overpotential, and surface-mediated electron transfer at high overpotential. We obtain evidence supporting this trend using the rotating ring disk electrode (RRDE) technique, which shows that the fraction of oxygen reduction reaction charge attributable to soluble Li(+)-O2(-)-based intermediates increases as the discharge overpotential reduces. Electrochemical quartz crystal microbalance (EQCM) measurements of oxygen reduction support this picture, and show that the dependence of the reaction mechanism on the applied potential explains the difference in Li2O2 morphologies observed at different discharge overpotentials: formation of large (∼250 nm-1 μm) toroids, and conformal coatings (<50 nm) at higher overpotentials. These results highlight that RRDE and EQCM can be used as complementary tools to gain new insights into the role of soluble and solid reaction intermediates in the growth of reaction products in metal-O2 batteries.

  1. Acid-mediated reactions under microfluidic conditions: A new strategy for practical synthesis of biofunctional natural products

    Katsunori Tanaka


    Full Text Available Microfluidic conditions were applied to acid-mediated reactions, namely, glycosylation, reductive opening of the benzylidene acetal groups, and dehydration, which are the keys to the practical synthesis of N-glycans and the immunostimulating natural product, pristane. A distinctly different reactivity from that in conventional batch stirring was found; the vigorous micromixing of the reactants with the concentrated acids is critical especially for the “fast” reactions to be successful. Such a common feature might be due to the integration of all favorable aspects of microfluidic conditions, i.e., efficient mixing, precise temperature control, and the easy handling of the reactive intermediate by controlling the residence time. The microfluidic reactions cited in this review indicate the need to reinvestigate the traditional or imaginary reactions which have so far been performed and evaluated only in batch apparatus, and therefore they could be recognized as a new strategy in synthesizing natural products of prominent biological activity in a “practical” and a “industrial” manner.

  2. Mediatization

    Hjarvard, Stig


    Mediatization research shares media effects studies' ambition of answering the difficult questions with regard to whether and how media matter and influence contemporary culture and society. The two approaches nevertheless differ fundamentally in that mediatization research seeks answers...... to these general questions by distinguishing between two concepts: mediation and mediatization. The media effects tradition generally considers the effects of the media to be a result of individuals being exposed to media content, i.e. effects are seen as an outcome of mediated communication. Mediatization...... research is concerned with long-term structural changes involving media, culture, and society, i.e. the influences of the media are understood in relation to how media are implicated in social and cultural changes and how these processes come to create new conditions for human communication and interaction...

  3. Visible-Light-Mediated Thiol-Ene Reactions through Organic Photoredox Catalysis.

    Zhao, Gaoyuan; Kaur, Sarbjeet; Wang, Ting


    Synthetically useful radical thiol-ene reactions can be initiated by visible-light irradiation in the presence of an organic photocatalyst, 9-mesityl-10-methylacridinum tetrafluoroborate. The key thiyl radical intermediates are generated upon quenching of the photoexcited catalyst with a variety of thiols. The success of this method requires only the use of near-stoichiometric levels of alkene coupling partners. Using these highly efficient metal-free conditions, thiol-ene reactions between carbohydrates and peptides can be accomplished in excellent yields.

  4. (Diisopinocampheyl)borane-mediated reductive aldol reactions of acrylate esters: enantioselective synthesis of anti-aldols.

    Allais, Christophe; Nuhant, Philippe; Roush, William R


    The (diisopinocampheyl)borane promoted reductive aldol reaction of acrylate esters 4 is described. Isomerization of the kinetically formed Z(O)-enolborinate 5Z to the thermodynamic E(O)-enolborinate 5E via 1,3-boratropic shifts, followed by treatment with representative achiral aldehydes, leads to anti-α-methyl-β-hydroxy esters 9 or 10 with excellent diastereo- (up to ≥20:1 dr) and enantioselectivity (up to 87% ee). The results of double asymmetric reactions of 5E with several chiral aldehydes are also presented.

  5. Synthesis of carbodiimides by I2/CHP-mediated cross-coupling reaction of isocyanides with amines under metal-free conditions.

    Zhu, Tong-Hao; Wang, Shun-Yi; Tao, Yang-Qing; Ji, Shun-Jun


    An I2/CHP-mediated cross-coupling reaction of isocyanides with readily accessible amines via C-N formation is described for carbodiimide synthesis in moderate to excellent yields. This represents a metal-free strategy for a coupling reaction of isocyanides with amines, and it provides an efficient approach for symmetric and unsymmetric functionalized carbodiimide derivative synthesis under mild conditions.

  6. Psychosocial stress enhances IgE-mediated triphasic cutaneous reaction in mice: Antagonism by Yokukan-san (a Kampo medicine and diazepam

    Eiichi Tahara


    Conclusions: The results of the present study indicate that IgE-mediated triphasic cutaneous reactions were exacerbated by social isolation stress and suggest that Yokukan-san and diazepam antagonize isolation stress-induced cutaneous reactions partly through their sedative action on social isolation stress.

  7. Triflic Anhydride-Mediated Beckmann Rearrangement Reaction of Β-Oximyl Amides: Access to 5-Iminooxazolines



    Facile and efficient synthesis of 5-iminooxazolines fromΑ, Α-disubstituted Β-oximyl amidesmediated by triflic anhydride $(Tf_{2}O)$ in the presence of 1,8-diazabicyclo(5.4.0)undec-7-ene (DBU) indichloromethane at room temperature is developed, and a mechanism involving tandem Beckmann rearrangementand intramolecular cyclization reaction is proposed.

  8. Synthesis of Highly Substituted Oxazoles through Iodine(III-Mediated Reactions of Ketones with Nitriles

    Yuji Hanzawa


    Full Text Available In the presence of trifluoromethanesulfonic acid (TfOH or bis(trifluoromethane-sulfonylimide (Tf2NH, iodosobenzene (PhI=O efficiently promoted the reactions of dicarbonyl compounds as well as monocarbonyl compounds with nitriles to give 2,4-disubstituted and 2,4,5-trisubstituted oxazole in a single step under the mild conditions.

  9. Total Synthesis of the Antimicrotubule Agent (+)-Discodermolide Using Boron-Mediated Aldol Reactions of Chiral Ketones.

    Paterson; Florence; Gerlach; Scott


    With a similar mechanism of action to taxol, the title compound 1 is a particularly promising candidate for development in cancer chemotherapy. This efficient synthesis, based on stereocontrolled aldol reactions, should help to overcome the scarce natural supply of 1 from the rare sponge source.

  10. Silver(Ⅰ)-mediated reaction of trimethylsilylated arylacetylenes with sulfonyl chlorides: Unexpected formation of vinyl sulfones

    Gui Sheng Deng; Teng Fei Sun


    A novel reaction of trimethylsilylated arylacetylenes with sulfonyl chlorides was performed in the presence of silver nitrate or triflate.Conjugated vinyl sulfones as dramatic products were obtained in moderate yields and with Z-selectivity.A free radical mechanism has been proposed to account for the formation of the products.

  11. Adaptive and innate immune reactions regulating mast cell activation: from receptor-mediated signaling to responses

    Tkaczyk, Christine; Jensen, Bettina M; Iwaki, Shoko


    In this article, we have described studies that have demonstrated that mast cells can be activated as a consequence of adaptive and innate immune reactions and that these responses can be modified by ligands for other receptors expressed on the surface of mast cells. These various stimuli...

  12. Modelling and simulation of a transketolase mediated reaction: Sensitivity analysis of kinetic parameters

    Sayar, N.A.; Chen, B.H.; Lye, G.J.


    In this paper we have used a proposed mathematical model, describing the carbon-carbon bond format ion reaction between beta-hydroxypyruvate and glycolaldehyde to synthesise L-erythrulose, catalysed by the enzyme transketolase, for the analysis of the sensitivity of the process to its kinetic par....... (C) 2009 Elsevier B.V. All rights reserved....

  13. Boron-mediated sequential alkyne insertion and C–C coupling reactions affording extended π-conjugated molecules

    Shoji, Yoshiaki; Tanaka, Naoki; Muranaka, Sho; Shigeno, Naoki; Sugiyama, Haruka; Takenouchi, Kumiko; Hajjaj, Fatin; Fukushima, Takanori


    C–C bond coupling reactions illustrate the wealth of organic transformations, which are usually mediated by organotransition metal complexes. Here, we show that a borafluorene with a B–Cl moiety can mediate sequential alkyne insertion (1,2-carboboration) and deborylation/Csp2–Csp2 coupling reactions, leading to aromatic molecules. The first step, which affords a borepin derivative, proceeds very efficiently between the borafluorene and various alkynes by simply mixing these two components. The second step is triggered by a one-electron oxidation of the borepin derivative, which results in the formation of a phenanthrene framework. When an excess amount of oxidant is used in the second step, the phenanthrene derivatives can be further transformed in situ to afford dibenzo[g,p]chrysene derivatives. The results presented herein will substantially expand the understanding of main group chemistry and provide a powerful synthetic tool for the construction of a wide variety of extended π-conjugated systems. PMID:27581519

  14. Sexual reactions in Mortierellales are mediated by the trisporic acid system.

    Schimek, Christine; Kleppe, Kathrin; Saleem, Abdel-Rahman; Voigt, Kerstin; Burmester, Anke; Wöstemeyer, Johannes


    Several species of Mortierella (Mortierellales, Zygomycota) were examined for substances regulating their sexual reactions. Compounds isolated from both mated and single growing Mortierella strains were purified by thin layer chromatography. Some of these compounds showed UV absorbance-characteristics similar to those of trisporoids, a group of compounds involved in sexual regulation in Mucorales. A compound with a 4-dihydromethyltrisporate-like absorbance spectrum was detected. To test for the interspecific sexual responses typically induced by trisporoids, the compounds extracted from Mortierella spp. were tested against the Mucorales Mucor mucedo and Phycomyces blakesleeanus and were found to induce sexual reactions in both tester strains. A gene encoding 4-dihydromethyltrisporate dehydrogenase was identified in several Mortierella species and the activity of the gene product was shown using a histochemical assay. We suggest that the regulation of sexual processes by trisporoids is common to both Mucorales and Mortierellales and may be more widespread within the Zygomycota.

  15. Transmission electron microscopic observations of acrosome and head abnormalities in impala (Aepyceros melampus sperm from the Kruger National Park

    D.J. Ackerman


    Full Text Available Sperm morphological features play an important role in semen evaluation. Exposure to a variety of chemical compounds, especially environmental endocrine disrupters, elicit abnormalities in sperm of certain species. Baseline data on ultrastructure of normal sperm as well as abnormalities observed concomitantly, are required before causal links between such substances and abnormalities can be established. Live spermatozoa were collected from the cauda epididymis of 64 impala rams in the Kruger National Park and studied by transmission electron microscopy to document normal sperm features and abnormalities. The following abnormalities of the acrosome and sperm head were documented from micrographs: Loose acrosome in various stages of disintegration, lip forming of the acrosome; bizarre head, crater defect, poor condensation of the nucleus and the Dag defect. The observed abnormalities were very similar to those reported for other members of the Bovidae. Different forms of a hollow sphere, formed by the nucleus and covered by an abnormal acrosome have not previously been described for other species.

  16. Influence of Boar and Semen Parameters on Motility and Acrosome Integrity in Liquid Boar Semen Stored for Five Days

    Sehested E


    Full Text Available Ninety ejaculates from a total of 76 AI boars were extended in Beltsville Thawing Solution (BTS. Boar identity, breed, weight of the ejaculate and sperm concentration were registered. Motility and acrosome integrity were assessed after storage at 16–18°C for 6, 30, 54, 78, and 102 h. Storage time had a significant influence on both motility (p

  17. Reclassifying Anaphylaxis to Neuromuscular Blocking Agents Based on the Presumed Patho-Mechanism: IgE-Mediated, Pharmacological Adverse Reaction or “Innate Hypersensitivity”?

    David Spoerl


    Full Text Available Approximately 60% of perioperative anaphylactic reactions are thought to be immunoglobulin IgE mediated, whereas 40% are thought to be non-IgE mediated hypersensitivity reactions (both considered non-dose-related type B adverse drug reactions. In both cases, symptoms are elicited by mast cell degranulation. Also, pharmacological reactions to drugs (type A, dose-related may sometimes mimic symptoms triggered by mast cell degranulation. In case of hypotension, bronchospasm, or urticarial rash due to mast cell degranulation, identification of the responsible mechanism is complicated. However, determination of the type of the underlying adverse drug reaction is of paramount interest for the decision of whether the culprit drug may be re-administered. Neuromuscular blocking agents (NMBA are among the most frequent cause of perioperative anaphylaxis. Recently, it has been shown that NMBA may activate mast cells independently from IgE antibodies via the human Mas-related G-protein-coupled receptor member X2 (MRGPRX2. In light of this new insight into the patho-mechanism of pseudo-allergic adverse drug reactions, in which as drug-receptor interaction results in anaphylaxis like symptoms, we critically reviewed the literature on NMBA-induced perioperative anaphylaxis. We challenge the dogma that NMBA mainly cause IgE-mediated anaphylaxis via an IgE-mediated mechanism, which is based on studies that consider positive skin test to be specific for IgE-mediated hypersensitivity. Finally, we discuss the question whether MRGPRX2 mediated pseudo-allergic reactions should be re-classified as type A adverse reactions.

  18. Discrimination of Arcobacter butzleri isolates by polymerase chain reaction-mediated DNA fingerprinting

    Atabay, H. I.; Bang, Dang Duong; Aydin, F.


    Aims: The objective of this study was to subtype Arcobacter butzleri isolates using RAPD-PCR. Methods and Results: Thirty-five A. butzleri isolates obtained from chicken carcasses were examined. PCR-mediated DNA fingerprinting technique with primers of the variable sequence motifs was used...... found to be contaminated with several different strains of A. butzleri . RAPD-PCR technique was found to be a useful technique for distinguishing A. butzleri isolates. Significance and Impact of the Study: The presence of several different A. butzleri strains on chicken carcasses may indicate multiple...

  19. Contribution of basophils to cutaneous immune reactions and Th2-mediated allergic responses

    Atsushi eOtsuka


    Full Text Available Basophils are potent effector cells of innate immunity and also play a role in T helper 2 (Th2-mediated allergic responses. But, although their in vitro functions are well studied, their in vivo functions remain largely unknown. However, several mouse models of basophil depletion have recently been developed and used to investigate basophil functions. For example, in a croton oil-induced model of irritant contact dermatitis in conditionally basophil-depleted transgenic mice, we found that basophils rapidly infiltrate inflamed skin and subsequently induce infiltration of eosinophils. We also showed that basophils induce Th2 skewing upon epicutaneous sensitization with various haptens and peptide antigens. Intriguingly, basophils also promoted Th2 polarization upon protein antigen exposure in the presence of dendritic cells (DCs. The dermal DC subset associated with Th2 skewing was recently identified as CD301b+ DC. Such studies with basophil-deficient mouse models have significantly improved our understanding of the mechanisms involved in human immune-related diseases. In this review, we will focus on the relative contribution of basophils and DCs to Th2-mediated allergic responses.

  20. Manchette-acrosome disorders during spermiogenesis and low efficiency of seminiferous tubules in hypercholesterolemic rabbit model

    Simón, Layla; Funes, Abi K.; Yapur, Martín A.; Cabrillana, María E.; Monclus, María A.; Boarelli, Paola V.; Vincenti, Amanda E.


    Hypercholesterolemia is a marker for several adult chronic diseases. Recently we demonstrated that sub/infertility is also associated to Hypercholesterolemia in rabbits. Seminal alterations included: abnormal sperm morphology, decreased sperm number and declined percentage of motile sperm, among others. In this work, our objective was to evaluate the effects of hypercholesterolemia on testicular efficiency and spermiogenesis, as the latter are directly related to sperm number and morphology respectively. Tubular efficiency was determined by comparing total number of spermatogenic cells with each cell type within the proliferation/differentiation compartments. We found lower testicular efficiency related to both a decrease in spermatogonial cells and an increase in germ cell apoptosis in hypercholesterolemic rabbits. On the other hand, spermiogenesis–the last step of spermatogenesis involved in sperm shaping–was detaily analyzed, particularly the acrosome-nucleus-manchette complex. The manchette is a microtubular-based temporary structure responsible in sperm cell elongation. We analyzed the contribution of actin filaments and raft microdomains in the arrangement of the manchette. Under fluorescence microscopy, spermatocyte to sperm cell development was followed in cells isolated from V to VIII tubular stages. In cells from hypercholesterolemic rabbits, abnormal development of acrosome, nucleus and inaccurate tail implantation were associated with actin–alpha-tubulin–GM1 sphingolipid altered distribution. Morphological alterations were also observed at electron microscopy. We demonstrated for the first time that GM1-enriched microdomains together with actin filaments and microtubules are involved in allowing the correct anchoring of the manchette complex. In conclusion, cholesterol enriched diets promote male fertility alterations by affecting critical steps in sperm development: spermatogenesis and spermiogenesis. It was also demonstrated that

  1. Mangiferin antagonizes TNF-α-mediated inflammatory reaction and protects against dermatitis in a mice model.

    Zhao, Yunpeng; Wang, Wenhan; Wu, Xihai; Ma, Xiaoqian; Qu, Ruize; Chen, Xiaomin; Liu, Chenghao; Liu, Yaoge; Wang, Xiaokai; Yan, Pengcheng; Zhang, Hao; Pan, Jingrui; Li, Weiwei


    This study aimed to investigate whether mangiferin played a protective role in a well-established dermatitis mouse model and tumor necrosis factor alpha (TNF-α)-induced RAW264.7 macrophages. Contact dermatitis is an inflammatory skin disease in the clinic, while its underlying mechanism still remains to be elucidated. Mangiferin, 1,3,6,7-tetrahydroxyxanthone-C2-β-d-glucoside (C-glucosyl xanthone), a natural antioxidant that was reported to inhibit inflammatory reactions, has been recently proved to be a potential therapy for inflammation. As a result, the oxazolone-induced dermatitis mice models were established to explore whether mangiferin has an anti-inflammatory role in vivo. The phosphate-buffered saline treatment groups showed emblematic skin inflammation, whereas the administration of mangiferin obviously inhibited dermatitis in the mice models. Furthermore, exogenous mangiferin alleviated the inflammatory reaction in TNF-α-induced macrophages by suppressing the production of inflammation- and oxidative stress-associated molecules. Also, mangiferin treatment repressed the activation of nuclear factor-kappaB signaling pathway. To sum up, mangiferin could provide a new target for the therapy and prevention of skin inflammation.

  2. Fixed-charge phosphine ligands to explore gas-phase coinage metal-mediated decarboxylation reactions.

    Vikse, Krista; Khairallah, George N; McIndoe, J Scott; O'Hair, Richard A J


    A combination of multistage mass spectrometry experiments and density functional theory (DFT) calculations were used to examine the decarboxylation reactions of a series of metal carboxylate complexes bearing a fixed-charge phosphine ligand, [(O3SC6H4)(C6H5)2PM(I)O2CR](-) (M = Cu, Ag, Au; R = Me, Et, benzyl, Ph). Collision-induced dissociation (CID) of these complexes using an LTQ linear ion mass spectrometer results in three main classes of reactions being observed: (1) decarboxylation; (2) loss of the phosphine ligand; (3) loss of carboxylic acid. The gas-phase unimolecular chemistry of the resultant decarboxylated organometallic ions, [(O3SC6H4)(C6H5)2PM(I)R](-), were also explored using CID experiments, and fragment primarily via loss of the phosphine ligand. Energy-resolved CID experiments on [(O3SC6H4)(C6H5)2PM(I)O2CR](-) (M = Cu, Ag, Au; R = Me, Et, benzyl, Ph) using a Q-TOF mass spectrometer were performed to gain a more detailed understanding of the factors influencing coinage metal-catalyzed decarboxylation and DFT calculations on the major fragmentation pathways aided in interpretation of the experimental results. Key findings are that: (1) the energy required for loss of the phosphine ligand follows the order Ag phosphine ligand on decarboxylation is also considered in comparison with previous studies on metal carboxylates that do not contain a phosphine ligand.

  3. Structure-Based Mechanism for Early PLP-Mediated Steps of Rabbit Cytosolic Serine Hydroxymethyltransferase Reaction

    Martino L. Di Salvo


    Full Text Available Serine hydroxymethyltransferase catalyzes the reversible interconversion of L-serine and glycine with transfer of one-carbon groups to and from tetrahydrofolate. Active site residue Thr254 is known to be involved in the transaldimination reaction, a crucial step in the catalytic mechanism of all pyridoxal 5′-phosphate- (PLP- dependent enzymes, which determines binding of substrates and release of products. In order to better understand the role of Thr254, we have expressed, characterized, and determined the crystal structures of rabbit cytosolic serine hydroxymethyltransferase T254A and T254C mutant forms, in the absence and presence of substrates. These mutants accumulate a kinetically stable gem-diamine intermediate, and their crystal structures show differences in the active site with respect to wild type. The kinetic and crystallographic data acquired with mutant enzymes permit us to infer that conversion of gem-diamine to external aldimine is significantly slowed because intermediates are trapped into an anomalous position by a misorientation of the PLP ring, and a new energy barrier hampers the transaldimination reaction. This barrier likely arises from the loss of the stabilizing hydrogen bond between the hydroxymethyl group of Thr254 and the ε-amino group of active site Lys257, which stabilizes the external aldimine intermediate in wild type SHMTs.

  4. Ubiquitin-activating enzyme (UBA1) is required for sperm capacitation, acrosomal exocytosis and sperm-egg coat penetration during porcine fertilization.

    Yi, Y-J; Zimmerman, S W; Manandhar, G; Odhiambo, J F; Kennedy, C; Jonáková, V; Maňásková-Postlerová, P; Sutovsky, M; Park, C-S; Sutovsky, P


    Protein ubiquitination is a stable, covalent post-translational modification that alters protein activity and/or targets proteins for proteolysis by the 26S proteasome. The E1-type ubiquitin-activating enzyme (UBA1) is responsible for ubiquitin activation, the initial step of ubiquitin-protein ligation. Proteasomal proteolysis of ubiquitinated spermatozoa and oocyte proteins occurs during mammalian fertilization, particularly at the site of sperm acrosome contact with oocyte zona pellucida. However, it is not clear whether the substrates are solely proteins ubiquitinated during gametogenesis or if de novo ubiquitination also occurs during fertilization supported by ubiquitin-activating and -conjugating enzymes present in the sperm acrosome. Along this line of inquiry, UBA1 was detected in boar sperm-acrosomal extracts by Western blotting (WB). Immunofluorescence revealed accumulation of UBA1 in the nuclei of spermatogonia, spermatocytes and spermatids, and in the acrosomal caps of round and elongating spermatids. Thiol ester assays utilizing biotinylated ubiquitin and isolated sperm acrosomes confirmed the enzymatic activity of the resident UBA1. A specific UBA1 inhibitor, PYR-41, altered the remodelling of the outer acrosomal membrane (OAM) during sperm capacitation, monitored using flow cytometry of fluorescein isothiocyanate-conjugated peanut agglutinin (FITC-PNA). Although viable and motile, the spermatozoa capacitated in the presence of PYR-41, showed significantly reduced fertilization rates during in vitro fertilization (IVF; p sperm capacitation and acrosomal function during fertilization.

  5. Transition from spiral waves to defect-mediated turbulence induced by gradient effects in a reaction-diffusion system

    Zhang, Chunxia; Zhang, Hong; Ouyang, Qi; Hu, Bambi; Gunaratne, Gemunu H.


    The transition from spiral waves to defect-mediated turbulence was studied in a spatial open reactor using Belousov-Zhabotinsky reaction. The experimental results show a new mechanism of the transition from spirals to spatiotemporal chaos, in which the gradient effects in the three-dimensional system are essential. The transition scenario consists of two stages: first, the effects of gradients in the third dimension cause a splitting of the spiral tip and a deletion of certain wave segments, generating new wave sources; second, the waves sent by the new wave sources undergo a backfire instability, and the back waves are laterally unstable. As a result, defects are automatically generated and fill all over the system. The result of numerical simulation using the FitzHugh-Nagumo model essentially agrees with the experimental observation.

  6. Single primer-mediated circular polymerase chain reaction for hairpin DNA cloning and plasmid editing.

    Huang, Jiansheng; Khan, Inamullah; Liu, Rui; Yang, Yan; Zhu, Naishuo


    We developed and validated a universal polymerase chain reaction (PCR) method, single primer circular (SPC)-PCR, using single primer to simultaneously insert and amplify a short hairpin sequence into a vector with a high success rate. In this method, the hairpin structure is divided into two parts and fused into a vector by PCR. Then, a single primer is used to cyclize the chimera into a mature short hairpin RNA (shRNA) expression vector. It is not biased by loop length or palindromic structures. Six hairpin DNAs with short 4-nucleotide loops were successfully cloned. Moreover, SPC-PCR was also applied to plasmid editing within 3 h with a success rate higher than 95%.

  7. Bacterial discrimination by means of a universal array approach mediated by LDR (ligase detection reaction

    Consolandi Clarissa


    Full Text Available Abstract Background PCR amplification of bacterial 16S rRNA genes provides the most comprehensive and flexible means of sampling bacterial communities. Sequence analysis of these cloned fragments can provide a qualitative and quantitative insight of the microbial population under scrutiny although this approach is not suited to large-scale screenings. Other methods, such as denaturing gradient gel electrophoresis, heteroduplex or terminal restriction fragment analysis are rapid and therefore amenable to field-scale experiments. A very recent addition to these analytical tools is represented by microarray technology. Results Here we present our results using a Universal DNA Microarray approach as an analytical tool for bacterial discrimination. The proposed procedure is based on the properties of the DNA ligation reaction and requires the design of two probes specific for each target sequence. One oligo carries a fluorescent label and the other a unique sequence (cZipCode or complementary ZipCode which identifies a ligation product. Ligated fragments, obtained in presence of a proper template (a PCR amplified fragment of the 16s rRNA gene contain either the fluorescent label or the unique sequence and therefore are addressed to the location on the microarray where the ZipCode sequence has been spotted. Such an array is therefore "Universal" being unrelated to a specific molecular analysis. Here we present the design of probes specific for some groups of bacteria and their application to bacterial diagnostics. Conclusions The combined use of selective probes, ligation reaction and the Universal Array approach yielded an analytical procedure with a good power of discrimination among bacteria.

  8. Molecular Detection of Methicillin-Resistant Staphylococcus aureus by Non-Protein Coding RNA-Mediated Monoplex Polymerase Chain Reaction

    Soo Yean, Cheryl Yeap; Selva Raju, Kishanraj; Xavier, Rathinam; Subramaniam, Sreeramanan; Gopinath, Subash C. B.; Chinni, Suresh V.


    Non-protein coding RNA (npcRNA) is a functional RNA molecule that is not translated into a protein. Bacterial npcRNAs are structurally diversified molecules, typically 50–200 nucleotides in length. They play a crucial physiological role in cellular networking, including stress responses, replication and bacterial virulence. In this study, by using an identified npcRNA gene (Sau-02) in Methicillin-resistant Staphylococcus aureus (MRSA), we identified the Gram-positive bacteria S. aureus. A Sau-02-mediated monoplex Polymerase Chain Reaction (PCR) assay was designed that displayed high sensitivity and specificity. Fourteen different bacteria and 18 S. aureus strains were tested, and the results showed that the Sau-02 gene is specific to S. aureus. The detection limit was tested against genomic DNA from MRSA and was found to be ~10 genome copies. Further, the detection was extended to whole-cell MRSA detection, and we reached the detection limit with two bacteria. The monoplex PCR assay demonstrated in this study is a novel detection method that can replicate other npcRNA-mediated detection assays. PMID:27367909

  9. Reaction kinetic model of the surface-mediated formation of PCDD/F from pyrolysis of 2-chlorophenol on a CuP/Silica suface

    Lomnicki, S.; Khachatryan, L.; Dellinger, B. [Louisiana State Univ., Baton Rouge (United States). Dept. of Chemistry


    One of the major challenges in developing predictive models of the surface mediated pollutant formation and fuel combustion is the construction of reliable reaction kinetic mechanisms and models. While the homogeneous, gas-phase chemistry of various light fuels such as hydrogen and methane is relatively well-known large uncertainties exist in the reaction paths of surface mediated reaction mechanisms for even these very simple species. To date, no detailed kinetic consideration of the surface mechanisms of formation of complex organics such as PCDD/F have been developed. In addition to the complexity of the mechanism, a major difficulty is the lack of reaction kinetic parameters (pre-exponential factor and activation energy) of surface reactions, Consequently, numerical studies of the surface-mediated formation of PCDD/F have often been incorporated only a few reactions. We report the development of a numerical multiple-step surface model based on experimental data of surface mediated (5% CuO/SiO2) conversion of 2-monochlorphenol (2-MCP) to PCDD/F under pyrolytic or oxidative conditions. A reaction kinetic model of the catalytic conversion of 2-MCP on the copper oxide catalyst under pyrolytic conditions was developed based on a detailed multistep surface reaction mechanism developed in our laboratory. The performance of the chemical model is assessed by comparing the numerical predictions with experimental measurements. SURFACE CHEMKIN (version 3.7.1) software was used for modeling. Our results confirm the validity of previously published mechanism of the reaction and provides new insight concerning the formation of PCDD/F formation in combustion processes. This model successfully explains the high yields of PCDD/F at low temperatures that cannot be explained using a purely gas-phase mode.

  10. Serum dependent cell-mediated immune reactions to Brugia pahangi infective larvae.

    Chandrashekar, R; Rao, U R; Subrahmanyam, D


    Fresh normal rat serum (fNRS) promoted adherence and cytotoxicity of albino rat neutrophils and macrophages to Brugia pahangi infective larvae (L3) in vitro. EDTA and not EGTA abolished the adherence activity suggesting the involvement of complement components via the alternate pathway. C3 molecules were detected on the surface of the parasite by immunofluorescence. fNRS depleted of complement by treatment with Zymosan A or of factor B by heating at 50 degrees C for 20 min, failed to promote cell adherence to the parasite. fNRS and cells from albino rat were more potent in inducing cytotoxicity to L3 than those from jird or Mastomys which may reflect the greater resistance offered by the albino rat to B. pahangi infection. In the presence of IgG and a heat labile factor, possibly complement, of immune serum, neutrophils and macrophages and to a lesser extent eosinophils adhered to and killed the larvae. Immune sera raised against microfilariae of different filarial parasites promoted cell-mediated cytotoxicity to B. pahangi L3 suggesting sharing of antigens between the two stages.

  11. Micellar-mediated extractive spectrophotometric determination of hydrogen sulfide/sulfide through Prussian Blue reaction: application to environmental samples.

    Pandurangappa, Malingappa; Samrat, Devaramani


    A sensitive surfactant-mediated extractive spectrophotometric method has been developed, based on the reaction of ferric iron with sulfide to form ferrous iron and its subsequent reaction with ferricyanide to form Prussian Blue, to quantify trace levels of hydrogen sulfide/sulfide in environmental samples. The method obeys Beer's law in the concentration range 2-10 microg of sulfide in 25 mL of aqueous phase with molar absorptivity (epsilon) of 3.92 x 10(4) L mol(-1) cm(-1). The colored species has been extracted into isoamyl acetate in the presence of a cationic surfactant i.e. cetylpyridinium chloride, to enhance the sensitivity of the method with epsilon value 5.2 x 10(4) L mol(-1) cm(-1). The relative standard deviation has been found to be 0.69% for 10 determinations at 4 microg of sulfide and the limit of detection was 0.009 microg mL(-1). The interference from common anions and cations has been studied. The proposed method has been applied to the determination of residual hydrogen sulfide in the laboratory fume hood as well as ambient atmospheric hydrogen sulfide in the vicinity of open sewer lines after fixing the analyte in ionic form using suitable trapping medium.

  12. The Effect of the Negotiator's Social Power as a Function of the Counterpart's Emotional Reactions in a Computer Mediated Negotiation

    Shlomo Hareli


    Full Text Available A negotiator’s own power and their counterpart’s emotional reaction to the negotiation both influence the outcome of negotiations. The present research addressed the question of their relative importance. On one hand, social power should be potent regardless of the other’s emotions. On the other hand, the counterpart’s emotional reactions inform about the ongoing state of the negotiation, and as such are more diagnostic than the more distal power cue. In a simulated computer mediated negotiation, 248 participants assumed the role of a vendor of computerized avionics test equipment and their objective was to negotiate the price, the warranty period, and the number of software updates that the buyer will receive free of charge. Participants negotiated the sale after being primed with either high or low power or not primed at all (control condition. They received information that their counterpart was either happy or angry or emotionally neutral. The findings showed that even though power was an important factor at the start of negotiations, the informative value of emotion information took precedence over time. This implies that emotional information may erase any advantage that counterparts have in a negotiation thanks to their higher social power.

  13. Mechanism of the Suzuki–Miyaura Cross-Coupling Reaction Mediated by [Pd(NHC)(allyl)Cl] Precatalysts

    Meconi, Giulia Magi


    Density functional theory calculations have been used to investigate the activation mechanism for the precatalyst series [Pd]-X-1–4 derived from [Pd(IPr)(R-allyl)X] species by substitutions at the terminal position of the allyl moiety ([Pd] = Pd(IPr); R = H (1), Me (2), gem-Me2 (3), Ph (4), X = Cl, Br). Next, we have investigated the Suzuki–Miyaura cross-coupling reaction for the active catalyst species IPr-Pd(0) using 4-chlorotoluene and phenylboronic acid as substrates and isopropyl alcohol as a solvent. Our theoretical findings predict an upper barrier trend, corresponding to the activation mechanism for the [Pd]-Cl-1–4 series, in good agreement with the experiments. They indeed provide a quantitative explanation of the low yield (12%) displayed by [Pd]-Cl-1 species (ΔG⧧ ≈ 30.0 kcal/mol) and of the high yields (≈90%) observed in the case of [Pd]-Cl-2–4 complexes (ΔG⧧ ≈ 20.0 kcal/mol). Additionally, the studied Suzuki–Miyaura reaction involving the IPr-Pd(0) species is calculated to be thermodynamically favorable and kinetically facile. Similar investigations for the [Pd]-Br-1–4 series, derived from [Pd(IPr)(R-allyl)Br], indicate that the oxidative addition step for IPr-Pd(0)-mediated catalysis with 4-bromotoluene is kinetically more favored than that with 4-chlorotoluene. Finally, we have explored the potential of Ni-based complexes [Ni((IPr)(R-allyl)X] (X = Cl, Br) as Suzuki–Miyaura reaction catalysts. Apart from a less endergonic reaction energy profile for both precatalyst activation and catalytic cycle, a steep increase in the predicted upper energy barriers (by 2.0–15.0 kcal/mol) is calculated in the activation mechanism for the [Ni]-X-1–4 series compared to the [Pd]-X-1–4 series. Overall, these results suggest that Ni-based precatalysts are expected to be less active than the Pd-based precatalysts for the studied Suzuki–Miyaura reaction.

  14. The Modification of Cellulosic Surface with Fatty Acids via Plasma Mediated Reactions

    Nada, Ahmed Ali Ahmed

    Much attention has been paid recently to understand the healing process made by the human body, in order to develop new approaches for promoting healing. The wound healing process includes four main phases, namely, hemostatic, inflammatory, proliferation, and remodeling, which take place successively. The human body can provide all the requirements of the healing process in normal wounds, unless there is a kind of deficiency of the skin function or massive fluid losses of vast wounds. Therefore, wound care of non-healing wounds has recently been the growing concern of many applications. The goal of this work is to explore the development of a new cellulose-based wound dressing composite that contain or release wound healing agents attained via dry textile chemical finishing techniques (thermal curing-plasma treatment). The synthesis of different wound healing agents derived from fatty acids and attached chemically to cellulose or even delivered through cyclodextrine modified cellulose are reported in this work. First, free fatty acids, which are obtained from commercial vegetable oils, were identified as wound healing agents. Many of these free acids are known to bind with and deactivate the proteases associated with inflammation at a wound site. Linoleic acid is extracted from commercial products of safflower seed oil while ricinoleic acid is obtained from castor oil. Conjugated linoleic acid was synthesized. Un-conjugated linoleic acid was used to prepare two derivatives namely linoleic azide and allylic ketone of linoleic acid. Different cellulose derivatives such as cellulose peroxide, iododeoxycellulose and cellulose diazonium salt in different degree of substitutions were synthesized in order to facilitate the free radical reaction with the fatty acid derivatives. New modified cellulosic products were synthesized by reacting the cellulosic and the linoleic acid derivatives via thermal or plasma technique and characterized by FT-IR ATR, the wettability test

  15. Molecular insight into IgE-mediated reactions to sesame (Sesamum indicum L.) seed proteins.

    Magni, Chiara; Ballabio, Cinzia; Restani, Patrizia; Fuggetta, Dalia; Alessandri, Claudia; Mari, Adriano; Bernardini, Roberto; Iacono, Iride Dello; Arlorio, Marco; Duranti, Marcello


    Food allergy is becoming a major public health concern in recent times. Several sesame seed allergenic proteins have been identified. However, sensitization toward these proteins does not follow a common and unique pattern of clinical reactivity, as shown by the differential geographic recognition of single proteins. To evaluate the sensitization profiles of 18 Italian individuals who experienced clinical symptoms after sesame seed consumption, including 4 anaphylactic reactions. Using an in vitro approach, we adopted a 2-dimensional electrophoretic technique combined with immunoblotting analyses by using sera from 18 Italian sesame-allergic patients. We showed the prevalent and almost exclusive reactivity of the sesame 11S globulin. We shed light on the active role of the basic subunit of this globulin family. The limited accessibility of this polypeptide chain, unless the interchain disulphide bonds are cleaved, may be one of the reasons for its structural/functional stability and, thus, great potential for induction of IgE reactivity. These results confirmed previous findings on the reactivity of the basic subunit of 11S globulin in various legume species. Moreover, this experimental approach proved to be useful for the noninvasive screening of specific reactivities in sensitized patients. Copyright © 2010 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  16. Mechanochemical solid-state synthesis of 2-aminothiazoles, quinoxalines and benzoylbenzofurans from ketones by one-pot sequential acid- and base-mediated reactions.

    Nagarajaiah, Honnappa; Mishra, Abhaya Kumar; Moorthy, Jarugu Narasimha


    α-Chloroketones - obtained by the atom-economical chlorination of ketones with trichloroisocyanuric acid (TCCA) in the presence of p-TSA under ball-milling conditions - were set up for a sequential base-mediated condensation reaction with thiourea/thiosemicarbazides, o-phenylenediamine and salicylaldehyde to afford 2-aminothiazoles, 2-hydrazinylthiazoles, quinoxalines and benzoylbenzofurans, respectively, in respectable yields. The viability of one-pot sequential acid- and base-mediated reactions in the solid state under ball-milling conditions is thus demonstrated.

  17. Polymerase chain reaction-mediated characterization of molds belonging to the Aspergillus flavus group and detection of Aspergillus parasiticus in peanut kernels by a multiplex polymerase chain reaction.

    Chen, Ruey-Shyang; Tsay, Jwu-Guh; Huang, Yu-Fen; Chiou, Robin Y Y


    The Aspergillus flavus group covers species of A. flavus and Aspergillus parasiticus as aflatoxin producers and Aspergillus oryzae and Aspergillus sojae as koji molds. Genetic similarity among these species is high, and aflatoxin production of a culture may be affected by cultivation conditions and substrate composition. Therefore, a polymerase chain reaction (PCR)-mediated method of detecting the aflatoxin-synthesizing genes to indicate the degree of risk a genotype has of being a phenotypic producer was demonstrated. In this study, 19 strains of the A. flavus group, including A. flavus, A. parasiticus, A. oryzae, A. sojae, and one Aspergillus niger, were subjected to PCR testing in an attempt to detect four genes, encoding for norsolorinic acid reductase (nor-1), versicolorin A dehydrogenase (ver-1), sterigmatocystin O-methyltransferase (omt-1), and a regulatory protein (apa-2), involved in aflatoxin biosynthesis. Concurrently, the strains were cultivated in yeast-malt (YM) broth for aflatoxin detection. Fifteen strains were shown to possess the four target DNA fragments. With regard to aflatoxigenicity, all seven aflatoxigenic strains possessed the four DNA fragments, and five strains bearing less than the four DNA fragments did not produce aflatoxin. When peanut kernels were artificially contaminated with A. parasiticus and A. niger for 7 days, the contaminant DNA was extractable from a piece of cotyledon (ca. 100 mg), and when subjected to multiplex PCR testing using the four pairs of primers coding for the above genes, they were successfully detected. The target DNA fragments were detected in the kernels infected with A. parasiticus, and none was detected in the sound (uninoculated) kernels or in the kernels infected with A. niger.

  18. Validation of non-fluorescent methods to reliably detect acrosomal and plasma membrane integrity of common marmoset (Callithrix jacchus) sperm.

    Valle, R R; Valle, C M R; Nichi, M; Muniz, J A P C; Nayudu, P L; Guimarães, M A B V


    Simple, rapid and stable sperm evaluation methods which have been optimized for common marmoset (Callithrix jacchus) are critical for studies involving collection and evaluation of sperm in the field. This is particularly important for new species groups such as Callitrichidae where the sperm have been little studied. Of this family, C. jacchus is the best known, and has been chosen as a model species for other members of the genus Callithrix. The fundamental evaluation parameters for sperm of any species are viability and acrosomal status. Semen samples were collected by penile vibratory stimulation. To evaluate sperm plasma membrane integrity, Eosin-Nigrosin was tested here for the common marmoset sperm to be used under field conditions. Further, a non-fluorescent stain for acrosome, the "Simple" stain, developed for domestic and wild cats, was tested on common marmoset sperm. This was compared with a fluorescent staining, Fluorescein isothiocyanate-Pisum sativum agglutinin (FITC-PSA), routinely used and validated for common marmoset at the German Primate Centre to evaluate acrosomal integrity. Results obtained with the "Simple" stain showed a marked differentiation between sperm with intact and non-intact acrosome both with and without ionophore treatment and closely correlated with results obtained with FITC-PSA. Temperature had no effect on the results with the "Simple" stain and the complete processing is simple enough to be carried out under field conditions. These findings indicated that the "Simple" stain and Eosin-Nigrosin provide rapid and accurate results for C. jacchus sperm and that those methods can be reliably used as field tools for sperm evaluation for this species.

  19. Myosin Va participates in acrosomal formation and nuclear morphogenesis during spermatogenesis of Chinese mitten crab Eriocheir sinensis.

    Xiao Sun

    Full Text Available BACKGROUND: The Chinese mitten crab Eriocheir sinensis belongs to the Class Crustacea, Decapoda, Brachyura. The spermatozoon of this species is of aflagellated type, it has a spherical acrosome surrounded by the cup-shaped nucleus, which are unique to brachyurans. For the past several decades, studies on the spermatogenesis of the mitten crab mainly focus on the morphology. Compared with the extensive study of molecular mechanism of spermatogenesis in mammals, relatively less information is available in crustacean species. Myosin Va, a member of Class V myosin, has been implicated in acrosome biogenesis and vesicle transport during spermatogenesis in mammals. In the present study we demonstrate the expression and cellular localization of myosin Va during spermatogenesis in E. sinensis. METHODOLOGY/PRINCIPAL FINDINGS: Western blot demonstrated that myosin Va is expressed during spermatogenesis. Immunocytochemical and ultrastructural analyses showed that myosin Va mainly localizes in the cytoplasm in spermatocytes. At the early stage of spermiogenesis, myosin Va binds to the endoplasmic reticulum vesicle (EV and proacrosomal granule (PG. Subsequently, myosin Va localizes within the proacrosomal vesicle (PV formed by PG and EV fusion and locates in the membrane complex (MC at the mid spermatid stage. At the late spermatid stage, myosin Va is associated with the shaping nucleus and mitochondria. In mature spermatozoon, myosin Va predominates in acrosomal tubule (AT and nucleus. CONCLUSIONS/SIGNIFICANCE: Our study demonstrates that myosin Va may be involved in acrosome biogenesis and nuclear morphogenesis during spermatogenesis in E. sinensis. Considering the distribution and molecular characteristics of myosin Va, we also propose a hypothesis of AT formation in this species. It is the first time to uncover the role of myosin Va in crustacean spermatogenesis.

  20. IBX-mediated oxidation of unactivated cyclic amines: application in highly diastereoselective oxidative Ugi-type and aza-Friedel-Crafts reactions.

    de Graaff, C; Bensch, L; van Lint, Matthijs J; Ruijter, E; Orru, R V A


    The first o-iodoxybenzoic acid (IBX) mediated oxidation of unactivated amines to imines is described. A range of meso-pyrrolidines were shown to be suitable substrates. The chemical space was further explored with one-pot oxidative Ugi-type and aza-Friedel-Crafts reactions, which proved to be highly diastereoselective.

  1. Increased chromatin fragmentation and reduced acrosome integrity in spermatozoa of red deer from lead polluted sites.

    Castellanos, Pilar; del Olmo, Enrique; Fernández-Santos, M Rocío; Rodríguez-Estival, Jaime; Garde, J Julián; Mateo, Rafael


    Vertebrates are constantly exposed to a diffuse pollution of heavy metals existing in the environment, but in some cases, the proximity to emission sources like mining activity increases the risk of developing adverse effects of these pollutants. Here we have studied lead (Pb) levels in spermatozoa and testis, and chromatin damage and levels of endogenous antioxidant activity in spermatozoa of red deer (Cervus elaphus) from a Pb mining area (n=37) and a control area (n=26). Deer from the Pb-polluted area showed higher Pb levels in testis parenchyma, epididymal cauda and spermatozoa, lower values of acrosome integrity, higher activity of glutathione peroxidase (GPx) and higher values of DNA fragmentation (X-DFI) and stainability (HDS) in sperm than in the control area. These results indicate that mining pollution can produce damage on chromatin and membrane spermatozoa in wildlife. The study of chromatin fragmentation has not been studied before in spermatozoa of wildlife species, and the sperm chromatin structure assay (SCSA) has been revealed as a successful tool for this purpose in species in which the amount of sperm that can be collected is very limited.

  2. Eicosanoids mediate nodulation reactions to bacterial Escherichia coli K 12 infections in larvae of the oriental blowfly,Chrysomya megacephala

    Bing Chen; Yong Wang; Fen Zhu; Chao-Liang Lei


    Nodulation is the predominant cellular defense reaction to bacterial challenges in insects.In this study,third instar larvae of Chrysomya megacephala were injected with bacteria,Escherichia coli K 12 (10~6 CFU/mL,2μL),immediately prior to injection of inhibitors of eicosanoid biosynthesis,which sharply reduced nodulation response.Test larvae were treated with specific inhibitors of phospholipase A_2 (dexamethasone),cyclooxygenase (indomethacin,ibuprofen and piroxicam),dual cyclo-oxygenase/lipoxygenase (phenidone) and lipoxygenase (esculetin) and these reduced nodulation except esculetin.The influence of bacteria was obvious within 2 h of injection (5 nodules/larva),and increased to a maximum after 8 h (with 15 nodules/larva),and then significantly reduced over 24 h (9 nodules/larva).The inhibitory influence of dexamethasone was apparent within 2 h of injection (4 vs.5 nodules/larva),and nodulation was significantly reduced,compared to control,over 24 h (5 vs.8 nodules/larva).Increased dosages of ibuprofen,indomethacin,piroxicam and phenidone led to decreased numbers of nodules.Nodules continued to exist during the pupal stage.However,the effects of dexamethasone were reversed by treating bacteria-injected insects with an eicosanoid-precursor polyunsaturated fatty acid,arachidonic acid.These findings approved our view that eicosanoid can mediate cellular defense mechanisms in response to bacterial infections in another Dipteran insect C.megacephala.

  3. Kinetic studies on surface-mediated activation of bovine factor XII and prekallikrein. Effects of kaolin and high-Mr kininogen on the activation reactions.

    Sugo, T; Kato, H; Iwanaga, S; Takada, K; Sakakibara, S


    The kaolin-mediated reciprocal activation of bovine factor XII and prekallikrein was divided into the following two reactions: the activation of factor XII by plasma kallikrein (reaction 1) and the activation of prekallikrein by factor XIIa (reaction 2). The effects of high-Mr kininogen and kaolin surface on the kinetics of these activation reactions were studied. High-Mr kininogen markedly enhanced the rate of reactions 1 and 2 in the presence of kaolin, and the enhancements were highly dependent on the concentrations of the protein cofactor and amount of kaolin surface. For the activation of factor XII by plasma kallikrein (reaction 1), high-Mr kininogen was required when a low concentration of factor XII and kaolin was used. The molar ratio of the protein cofactor to factor XII for optimal activation was found to be approximately 1:1. The apparent Km value and the kcat/Km value for plasma kallikrein on factor XII were calculated to be 4 nM and 5.2 X 10(7) s-1 X M-1, respectively. The activation of prekallikrein by factor XIIa, (reaction 2) proceeded even in the absence of high-Mr kininogen and kaolin. The addition of the protein cofactor and surface to the reaction mixture remarkably accelerated the reaction, and the apparent Km value for factor XIIa on prekallikrein was reduced from 1 microM to 40 nM. Moreover, the kcat/Km value was altered from 7.3 X 10(4) to 1.1 X 10(6) s-1 X M-1). These results suggest that high-Mr kininogen accelerates the surface-mediated activation of factor XII and prekallikrein by enhancing the susceptibility of factor XII to plasma kallikrein, on the one hand, and the affinity of factor XIIa for prekallikrein, on the other hand. Kaolin may play an important role in the concentration and organization of these components on the negatively charged surface.

  4. 2-Hydroxy-3-methoxybenzoic acid attenuates mast cell-mediated allergic reaction in mice via modulation of the FcεRI signaling pathway

    Kim, Yeon-Yong; Je, In-Gyu; Kim, Min Jong; Kang, Byeong-Cheol; Choi, Young-Ae; Baek, Moon-Chang; Lee, Byungheon; Choi, Jin Kyeong; Park, Hae Ran; Shin, Tae-Yong; Lee, Soyoung; Yoon, Seung-Bin; Lee, Sang-Rae; Khang, Dongwoo; Kim, Sang-Hyun


    Mast cells are important effector cells in immunoglobulin (Ig) E-mediated allergic reactions such as asthma, atopic dermatitis and rhinitis. Vanillic acid, a natural product, has shown anti-oxidant and anti-inflammatory activities. In the present study, we investigated the anti-allergic inflammatory effects of ortho-vanillic acid (2-hydroxy-3-methoxybenzoic acid, o-VA) that was a derivative of vanillic acid isolated from Amomum xanthioides. In mouse anaphylaxis models, oral administration of ...

  5. Osmotic tolerance limits and effects of cryoprotectants on the motility, plasma membrane integrity and acrosomal integrity of rat sperm.

    Si, Wei; Benson, James D; Men, Hongsheng; Critser, John K


    Osmotic stress is an important factor that can result in cell damage during cryopreservation. The objectives of this study were to determine: (1) isosmotic sperm cell volume; (2) osmotically inactive volume; (3) osmotic tolerance limits of rat sperm; and (4) the effects of addition and removal of glycerol (Gly), ethylene glycol (EG), propylene glycol (PG) or dimethyl sulfoxide (Me(2)SO) on rat sperm function. Sperm from Fischer 344 and Sprague-Dawley rats were used in this study. An electronic particle counter was used to measure the cell volume of rat sperm. Computer-assisted sperm motility analysis and flow-cytometric analysis were used to assess sperm motility, plasma membrane and acrosomal integrity. The isosmotic sperm cell volumes of the two strains were 37.0+/-0.1 and 36.2+/-0.2 microm(3), respectively. Rat sperm behaved as linear osmometers from 260 to 450 mOsm, and the osmotically inactive sperm volumes of the two strains were 79.8+/-1.5% and 81.4+/-2.2%, respectively. Rat sperm have very limited osmotic tolerances. The sperm motility and the sperm plasma membranes of both strains were sensitive to anisosmotic treatments, but the acrosomes of both strains were more sensitive to hyposmotic than hyperosmotic conditions. The one-step addition and removal of Me(2)SO showed the most deleterious effect on rat sperm motility, plasma membrane integrity, and acrosomal integrity among the four cryoprotectants. These data characterizing rat sperm osmotic behavior, osmotic and cryoprotectant tolerance will be used to design cryopreservation protocols for rat sperm.

  6. DNA fragmentation of human sperm can be detected by ligation-mediated real-time polymerase chain reaction.

    Lim, Jung Jin; Lee, Jin Il; Kim, Dong Hwan; Song, Seung-Hun; Kim, Hyung Joon; Lee, Woo Sik; Lee, Dong Ryul


    To determine whether ligation-mediated real-time polymerase chain reaction (LM-RT-PCR), which combines LM-PCR, and RT-PCR, can detect sperm DNA fragmentation (DF) in human semen samples. Three-way comparison of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), sperm chromatin dispersion (SCD), and LM-RT-PCR for detecting sperm DNA fragmentation. University hospital-based research laboratory. Twenty-five men presenting at an infertility clinic. Basic analysis of sperm concentration, motility, vitality, and morphology, with each semen sample equally divided into three aliquots that were evaluated for fragmentation using TUNEL, SCD, and LM-RT-PCR assays. In TUNEL and SCD assays, counts of the number of sperm with tetramethylrhodamine (TMR) red signals or no halo; in LM-RT-PCR results, evaluation of the threshold cycles (Ct) and relative fluorescence unit (RFU) values. The median percentage of sperm with positive results for fragmentation in the TUNEL and SCD assays were 20.5% and 20.7%, respectively. To compare the accuracy of the TUNEL, SCD, and LM-RT-PCR assays, we divided the semen samples into two groups according to the TUNEL results: low and high percentage of sperm fragmentation. In the LM-RT-PCR results, the values of the cycles of threshold (Ct) and relative fluorescence unit (RFU) statistically significantly differed between the low and high percentage of sperm fragmentation groups. Comparisons among the TUNEL, SCD, and LM-RT-PCR assays revealed that the correlation patterns according to DNA fragmentation were similar in both the groups with high and low percentage of DNA fragmentation. Our morphologic analysis indicated that the fragmentation of sperm DNA did not appear to influence sperm morphology. These results indicate that the LM-RT-PCR technique is another useful tool for detecting DNA fragmentation, a parameter of sperm quality in human semen alone or combined with TUNEL or SCD assays. Copyright © 2013 American Society for

  7. IgE-mediated allergic reactions to fruit gums and investigation of cross-reactivity between gelatine and modified gelatine-containing products.

    Wahl, R; Kleinhans, D


    A 32-year-old female reacted with a contact urticaria syndrome after eating 'gummy bears' (fruit gums). The reaction began in the oral mucosa and led to treatment on an inpatient basis. RAST measurements with allergen discs produced with gelatine and gelatine-containing products (among them 'gummy bears') demonstrated the presence of IgE antibodies in the serum of this patient. Proteins with molecular weights in the range of 40-120 kD were identified as the allergens in gelatine by using Western blot analysis. RAST inhibition showed cross-reactivity between gelatine, gelatine-containing products and the modified gelatine used in some plasma substitutes. Allergic reactions towards coloured fruit candies and 'gummy bears' may result from an IgE-mediated hypersensitivity towards gelatine. The long-known anaphylactoid reactions towards gelatine-containing plasma substitutes may, at least in part, be of an allergic nature.

  8. Dynamic pathways to mediate reactions buried in thermal fluctuations. I. Time-dependent normal form theory for multidimensional Langevin equation.

    Kawai, Shinnosuke; Komatsuzaki, Tamiki


    We present a novel theory which enables us to explore the mechanism of reaction selectivity and robust functions in complex systems persisting under thermal fluctuation. The theory constructs a nonlinear coordinate transformation so that the equation of motion for the new reaction coordinate is independent of the other nonreactive coordinates in the presence of thermal fluctuation. In this article we suppose that reacting systems subject to thermal noise are described by a multidimensional Langevin equation without a priori assumption for the form of potential. The reaction coordinate is composed not only of all the coordinates and velocities associated with the system (solute) but also of the random force exerted by the environment (solvent) with friction constants. The sign of the reaction coordinate at any instantaneous moment in the region of a saddle determines the fate of the reaction, i.e., whether the reaction will proceed through to the products or go back to the reactants. By assuming the statistical properties of the random force, one can know a priori a well-defined boundary of the reaction which separates the full position-velocity space in the saddle region into mainly reactive and mainly nonreactive regions even under thermal fluctuation. The analytical expression of the reaction coordinate provides the firm foundation on the mechanism of how and why reaction proceeds in thermal fluctuating environments.

  9. Inhibition of Hamster Sperm Acrosomal Enzyme by Gossypol is Closely Associated with the Decrease in Fertilization Capacity

    YuanYu-ying; ShiQi-xian


    To elucidate the mechanism of sterility induced by gossypol,we studied the relationship between the activities of acrosomal enzymes and their fertilizing capacity in the hamster. The results showed that the ability of spermatozoa to penetrate into bovine cervical mucus,hyperactivated motility(HAM)and fertility in vivo were significantly inhibited when spermatozoa were exposed to gossypol (2.5μg-60μg/mL)for 15 min in vitro.Also,following administration of gossypol (12.5mg/kg/day)for 6 weeks,sperm motility,HAM and rate of fertilization in vitro by the hamster cauda epididymal spermatozoa were significantly decreased and the extracts of testis delayed dispersion of the cumulus oophorus cells,suggesting that hyaluronidase and other acrosomal enzymes might be inhibited by gossypol.In addition, acrosin and arylsulfatase activities were also markedly inhibited.These data show that the inhibition of acrosin and arylsulfatase activities is the main cause of gossypol-induced infertility.The inhibition was dependent upon gossypol dose and the duration of administration.Thus, the assay of acrosin and arylsulfatase activities may provide a useful tool for monitoring sterility induced by gossypol.

  10. Quantitative changes of Ricinus communis agglutinin I and Helix pomatia lectin binding sites in the acrosome of rat spermatozoa during epididymal transit.

    Hermo, L; Winikoff, R; Kan, F W


    During passage through the epididymis, spermatozoa undergo a number of changes which result in their acquisition of fertility and motility. Some of the changes that occur include loss of the cytoplasmic droplet and changes in sperm morphology, metabolism and properties of the nucleus and plasma membrane. Changes have also been reported in the acrosomic system of mammalian spermatozoa during their transit through the epididymis. In the present study, the quantitative changes of the glycoconjugate content in the acrosome of rat spermatozoa were examined during their passage through the epididymis using lectin-colloidal gold cytochemistry. Various regions of the epididymis (initial segment, caput, corpus and cauda epididymidis) were fixed by perfusion with 1% or 2% glutaraldehyde buffered in sodium cacodylate (0.1 M), dehydrated in ethanol and embedded without osmication in Lowicryl K4M. Lectin-colloidal gold labeling was performed on thin sections using Ricinus communis agglutinin I (RCA I) or Helix pomatia lectin (HPL) to detect D-galactose- and N-acetyl-D-galactosamine-containing glycoconjugates, respectively. The labeling density over the acrosome of the acrosomic system was evaluated as the number of gold particles per microns 2 of profile area using a Zeiss MOP-3 image analyzer. The overall mean labeling densities over the acrosome of spermatozoa for each lectin was estimated from 4 rats and over the four distinct epididymal regions. The mean labeling density of the acrosome with RCA I and HPL showed a similar pattern along the epididymis, although RCA I revealed approximately twice as many gold particles per epididymal region. In either case, there was a significant decrease in the labeling density of the acrosome of spermatozoa between the initial segment or caput epididymidis and cauda epididymidis (p less than 0.01). A similar decrease was also noted between the initial segment and corpus epididymidis (p less than 0.01). No change was found between the

  11. A Triple-Stain Flow Cytometric Method to Assess Plasma- and Acrosome-Membrane Integrity of Cryopreserved Bovine Sperm Immediately after Thawing in Presence of Egg-Yolk Particles

    Nagy, S.; Jansen, J.; Topper, E.K.; Gadella, B.M.


    Simultaneously evaluating postthaw viability and acrosome integrity of spermatozoa by flow cytometry would provide a valuable testing tool in both research and routine work. In the present study, a new triple-stain combination was developed for the simultaneous evaluation of viability and acrosome i

  12. Scope and mechanism of the highly stereoselective metal-mediated domino aldol reactions of enolates with aldehydes

    Engelen, Bernward; Panthöfer, Martin; Deiseroth, Hans-Jörg; Schlirf, Jens


    Summary A one-pot transformation, which involves the reaction of ketones with aldehydes in the presence of metal halides to furnish tetrahydro-2H-pyran-2,4-diols in a highly diastereoselective manner, is investigated thoroughly by experiments and computations. The reaction was also successfully implemented on a flow micro reactor system. PMID:27340472

  13. The effect of salmeterol and salbutamol on mediator release and skin responses in immediate and late phase allergic cutaneous reactions

    Petersen, Lars Jelstrup; Skov, P S


    by suction blister technique. RESULTS: Both beta2-agonists inhibited allergen-induced histamine release and wheal and flare reactions with maximum inhibition of 40-50% at 10(-6) M, a concentration which reduced PGD2 synthesis by approximately 55%. Histamine release by codeine and skin reactions to codeine...

  14. Production of Organic Grain Coatings by Surface-Mediated Reactions and the Consequences of This Process for Meteoritic Constituents

    Nuth, Joseph A., III; Johnson, Natasha M.


    When hydrogen, nitrogen and CO are exposed to amorphous iron silicate surfaces at temperatures between 500 - 900K, a carbonaceous coating forms via Fischer-Tropsch type reactions. Under normal circumstances such a catalytic coating would impede or stop further reaction. However, we find that this coating is a better catalyst than the amorphous iron silicates that initiate these reactions. The formation of a self-perpetuating catalytic coating on grain surfaces could explain the rich deposits of macromolecular carbon found in primitive meteorites and would imply that protostellar nebulae should be rich in organic material. Many more experiments are needed to understand this chemical system and its application to protostellar nebulae.

  15. Pd/C-mediated dual C-C bond forming reaction in water: synthesis of 2,4-dialkynylquinoline

    Reddy, Ellanki A.; Islam, Aminul; Venu, Bolla K. [Dr. Reddy' s Laboratories Limited, Hyderabad, Andhra Pradesh (India); Mukkanti, K. [JNT University, Hyderabad, Andhra Pradesh (India). Inst. of Science and Technology. Chemistry Division; Pal, Manojit, E-mail: [Matrix Laboratories Ltd., Medak District, Andra Pradesh (India). New Drug Discovery. R and D Center


    Pd/C facilitated dual C-C bond forming reaction between 2,4-diiodoquinoline and terminal alkynes in water providing a practical and one-step synthesis of 2,4-dialkynylquinolines. A number of related quinoline derivatives were prepared in good to excellent yields using this water-based methodology. The use of other palladium catalysts and solvents was examined and the mechanism of the reaction has been discussed. (author)

  16. Use of Cyclic Allylic Bromides in the Zinc–Mediated Aqueous Barbier–Grignard Reaction

    Suzanne M. Perala


    Full Text Available The zinc–mediated aqueous Barbier–Grignard reaction of cyclic allylic bromide substrates with various aldehydes and ketones to afford homoallylic alcohols was investigated. Aromatic aldehydes and ketones afforded adducts in good yields (66–90% and with good diastereoselectivities. Non–aromatic aldehydes also reacted well under these conditions, but only poor yields were obtained with non–aromatic ketones. Regioselectivity was high when some substituted cyclic allylic bromides were investigated.

  17. Electrophilic Pt(II) complexes: precision instruments for the initiation of transformations mediated by the cation-olefin reaction.

    Felix, Ryan J; Munro-Leighton, Colleen; Gagné, Michel R


    A discontinuity exists between the importance of the cation-olefin reaction as the principal C-C bond forming reaction in terpene biosynthesis and the synthetic tools for mimicking this reaction under catalyst control; that is, having the product identity, stereochemistry, and functionality under the control of a catalyst. The main reason for this deficiency is that the cation-olefin reaction starts with a reactive intermediate (a carbocation) that reacts exothermically with an alkene to reform the reactive intermediate; not to mention that reactive intermediates can also react in nonproductive fashions. In this Account, we detail our efforts to realize catalyst control over this most fundamental of reactions and thereby access steroid like compounds. Our story is organized around our progress in each component of the cascade reaction: the metal controlled electrophilic initiation, the propagation and termination of the cyclization (the cyclase phase), and the turnover deplatinating events. Electrophilic Pt(II) complexes efficiently initiate the cation-olefin reaction by first coordinating to the alkene with selection rules that favor less substituted alkenes over more substituted alkenes. In complex substrates with multiple alkenes, this preference ensures that the least substituted alkene is always the better ligand for the Pt(II) initiator, and consequently the site at which all electrophilic chemistry is initiated. This control element is invariant. With a suitably electron deficient ligand set, the catalyst then activates the coordinated alkene to intramolecular addition by a second alkene, which initiates the cation-olefin reaction cascade and generates an organometallic Pt(II)-alkyl. Deplatination by a range of mechanisms (β-H elimination, single electron oxidation, two-electron oxidation, etc.) provides an additional level of control that ultimately enables A-ring functionalizations that are orthogonal to the cyclase cascade. We particularly focus on

  18. Study on the reactions of azo compounds with acyl halides mediated by Sm/TiCl4


    Amides can be obtained in good to excellent yield by Sm/TiCl4 mediated reductive cleavage of N=N bond in azo compounds and successive acylation in one pot. It offers an alternative method for the synthesis of amides from very simple starting materials directly.

  19. A case study of the mechanism of alcohol-mediated Morita Baylis-Hillman reactions. The importance of experimental observations.

    Plata, R Erik; Singleton, Daniel A


    The mechanism of the Morita Baylis-Hillman reaction has been heavily studied in the literature, and a long series of computational studies have defined complete theoretical energy profiles in these reactions. We employ here a combination of mechanistic probes, including the observation of intermediates, the independent generation and partitioning of intermediates, thermodynamic and kinetic measurements on the main reaction and side reactions, isotopic incorporation from solvent, and kinetic isotope effects, to define the mechanism and an experimental mechanistic free-energy profile for a prototypical Morita Baylis-Hillman reaction in methanol. The results are then used to critically evaluate the ability of computations to predict the mechanism. The most notable prediction of the many computational studies, that of a proton-shuttle pathway, is refuted in favor of a simple but computationally intractable acid-base mechanism. Computational predictions vary vastly, and it is not clear that any significant accurate information that was not already apparent from experiment could have been garnered from computations. With care, entropy calculations are only a minor contributor to the larger computational error, while literature entropy-correction processes lead to absurd free-energy predictions. The computations aid in interpreting observations but fail utterly as a replacement for experiment.

  20. Computational tools for mechanistic discrimination in the reductive and metathesis coupling reactions mediated by titanium(IV) isopropoxide

    Akshai Kumar; Ashoka G Samuelson


    A theoretical study has been carried out at the B3LYP/LANL2DZ level to compare the reactivity of phenyl isocyanate and phenyl isothiocyanate towards titanium(IV) alkoxides. Isocyanates are shown to favour both mono insertion and double insertion reactions. Double insertion in a head-to-tail fashion is shown to be more exothermic than double insertion in a head-to-head fashion. The head-to-head double insertion leads to the metathesis product, a carbodiimide, after the extrusion of carbon dioxide. In the case of phenyl isothiocyanate, calculations favour the formation of only mono insertion products. Formation of a double insertion product is highly unfavourable. Further, these studies indicate that the reverse reaction involving the metathesis of N,N'-diphenyl carbodiimide with carbon dioxide is likely to proceed more efficiently than the metathesis reaction with carbon disulphide. This is in excellent agreement with experimental results as metathesis with carbon disulphide fails to occur. In a second study, multilayer MM/QM calculations are carried out on intermediates generated from reduction of titanium(IV) alkoxides to investigate the effect of alkoxy bridging on the reactivity of multinuclear Ti species. Bimolecular coupling of imines initiated by Ti(III) species leads to a mixture of diastereomers and not diastereoselective coupling of the imine. However if the reaction is carried out by a trimeric biradical species, diastereoselective coupling of the imine is predicted. The presence of alkoxy bridges greatly favours the formation of the d,l (±) isomer, whereas the intermediate without alkoxy bridges favours the more stable meso isomer. As a bridged trimeric species, stabilized by bridging alkoxy groups, correctly explains the diastereoselective reaction, it is the most likely intermediate in the reaction.

  1. Presence and function of dopamine transporter (DAT in stallion sperm: dopamine modulates sperm motility and acrosomal integrity.

    Javier A Urra

    Full Text Available Dopamine is a catecholamine with multiple physiological functions, playing a key role in nervous system; however its participation in reproductive processes and sperm physiology is controversial. High dopamine concentrations have been reported in different portions of the feminine and masculine reproductive tract, although the role fulfilled by this catecholamine in reproductive physiology is as yet unknown. We have previously shown that dopamine type 2 receptor is functional in boar sperm, suggesting that dopamine acts as a physiological modulator of sperm viability, capacitation and motility. In the present study, using immunodetection methods, we revealed the presence of several proteins important for the dopamine uptake and signalling in mammalian sperm, specifically monoamine transporters as dopamine (DAT, serotonin (SERT and norepinephrine (NET transporters in equine sperm. We also demonstrated for the first time in equine sperm a functional dopamine transporter using 4-[4-(Dimethylaminostyryl]-N-methylpyridinium iodide (ASP(+, as substrate. In addition, we also showed that dopamine (1 mM treatment in vitro, does not affect sperm viability but decreases total and progressive sperm motility. This effect is reversed by blocking the dopamine transporter with the selective inhibitor vanoxerine (GBR12909 and non-selective inhibitors of dopamine reuptake such as nomifensine and bupropion. The effect of dopamine in sperm physiology was evaluated and we demonstrated that acrosome integrity and thyrosine phosphorylation in equine sperm is significantly reduced at high concentrations of this catecholamine. In summary, our results revealed the presence of monoamine transporter DAT, NET and SERT in equine sperm, and that the dopamine uptake by DAT can regulate sperm function, specifically acrosomal integrity and sperm motility.

  2. Presence and function of dopamine transporter (DAT) in stallion sperm: dopamine modulates sperm motility and acrosomal integrity.

    Urra, Javier A; Villaroel-Espíndola, Franz; Covarrubias, Alejandra A; Rodríguez-Gil, Joan Enric; Ramírez-Reveco, Alfredo; Concha, Ilona I


    Dopamine is a catecholamine with multiple physiological functions, playing a key role in nervous system; however its participation in reproductive processes and sperm physiology is controversial. High dopamine concentrations have been reported in different portions of the feminine and masculine reproductive tract, although the role fulfilled by this catecholamine in reproductive physiology is as yet unknown. We have previously shown that dopamine type 2 receptor is functional in boar sperm, suggesting that dopamine acts as a physiological modulator of sperm viability, capacitation and motility. In the present study, using immunodetection methods, we revealed the presence of several proteins important for the dopamine uptake and signalling in mammalian sperm, specifically monoamine transporters as dopamine (DAT), serotonin (SERT) and norepinephrine (NET) transporters in equine sperm. We also demonstrated for the first time in equine sperm a functional dopamine transporter using 4-[4-(Dimethylamino)styryl]-N-methylpyridinium iodide (ASP(+)), as substrate. In addition, we also showed that dopamine (1 mM) treatment in vitro, does not affect sperm viability but decreases total and progressive sperm motility. This effect is reversed by blocking the dopamine transporter with the selective inhibitor vanoxerine (GBR12909) and non-selective inhibitors of dopamine reuptake such as nomifensine and bupropion. The effect of dopamine in sperm physiology was evaluated and we demonstrated that acrosome integrity and thyrosine phosphorylation in equine sperm is significantly reduced at high concentrations of this catecholamine. In summary, our results revealed the presence of monoamine transporter DAT, NET and SERT in equine sperm, and that the dopamine uptake by DAT can regulate sperm function, specifically acrosomal integrity and sperm motility.

  3. Pyrovanadolysis, a Pyrophosphorolysis-like Reaction Mediated by Pyrovanadate, Mn2+, and DNA Polymerase of Bacteriophage T7

    Akabayov, Barak; Kulczyk, Arkadiusz W.; Akabayov, Sabine R.; Theile, Christopher; McLaughlin, Larry W.; Beauchamp, Benjamin; van Oijen, Antoine M.; Richardson, Charles C.


    DNA polymerases catalyze the 3'-5'-pyrophosphorolysis of a DNA primer annealed to a DNA template in the presence of pyrophosphate (PPi). In this reversal of the polymerization reaction, deoxynucleotides in DNA are converted to deoxynucleoside 5'-triphosphates. Based on the charge, size, and geometry

  4. Concerted action of two avirulent spore effectors activates Reaction to Puccinia graminis 1 (Rpg1)-mediated cereal stem rust resistance

    The barley stem rust resistance gene Reaction to Puccinia graminis 1 (Rpg1), encoding a receptor-like kinase, confers durable resistance to the stem rust pathogen Puccinia graminis f. sp. tritici. The fungal urediniospores form adhesion structures with the leaf epidermal cells within 1 h of inocula...

  5. An iridium-mediated C-H activation/CO2-carboxylation reaction of 1,1-bisdiphenylphosphinomethane.

    Langer, Jens; Fabra, María José; García-Orduña, Pilar; Lahoz, Fernando J; Görls, Helmar; Oro, Luis A; Westerhausen, Matthias


    The reaction of 1,1-bisdiphenylphosphinomethane (dppm, 4 eq.) with [IrCl(coe)(2)](2) results in a solvent dependent equilibrium from which the complexes [IrCl(dppm)(dppm-H)(H)] (1) and [Ir(dppm)(2)]Cl (2) were isolated. When 2 is dissolved in methanol, [IrCl(dppm)(2)(H)][OCH(3)] (4) is formed as dominant species in solution. The C-H activation reaction which leads to 1 and 4 can be suppressed by adding an additional dppm ligand per iridium center resulting in the formation of [Ir(dppm)(3)]Cl (5). If the reaction of dppm with [IrX(coe)(2)](2) (X = Cl, I) is performed under an atmosphere of CO(2) the complexes [IrX(dppm)(H){(Ph(2)P)(2)C-COOH}] (6: X = Cl; 7: X = I) are formed by a CH activation/CO(2) carboxylation sequence. The reaction of 6 with NH(4)PF yields [IrCl(dppm)(2)(H)]PF(6).(10). Additionally the lithium compounds [Li(dme)(2)(dppm-H)] (3) and [Li(dme){(Ph(2)P)(2)CHCOO}](2) (8) were prepared for comparison. The molecular structures of the compounds 1, 3, 5, 7, 8 and of the related iridium complex [IrCl(dppm)(2)(H)]I (11) are reported.

  6. Cell-mediated immunity to histocompatibility antigens : controlling factors, with emphasis on Graft-versus-host reactions in mice

    H. Bril (Herman)


    textabstractGraft-versus-Host (GvH) disease is characterized by weight loss, diarrhea, skin lesions, hypofunction of the immune system with concomitant infections, etc. This syndrome is potentially lethal. GvH reactions, which underly this disease, may occur when immunocompetent T lymphocytes are tr

  7. Laccase mediator systems for eco-friendly production of medium-density fiberboard (MDF) on a pilot scale: physicochemical analysis of the reaction mechanism.

    Euring, Markus; Rühl, Martin; Ritter, Nina; Kües, Ursula; Kharazipour, Alireza


    Increasing prices of petrochemical resins and possible harmful formaldehyde emissions from conventionally produced wood composites have resulted in increased interest in enzymatic binder systems as environmentally friendly alternatives for gluing lignocellulosic products. In this study, laccase mediator systems (LMSs) were used to activate lignin on wood fiber surfaces in the pilot-scale production of medium-density fiberboard (MDF) using a dry process. Three different mediators were applied: 4-hydroxybenzoic acid (HBA), 1-hydroxybenzotriazole (HBT), and acetosyringone (AS) of which HBA performed best. The mechanical properties of the manufactured boards produced with thermomechanical pulp (TMP) fibers, laccase, and HBA fulfilled all required European standards for wood-based panels. Oxygen consumption rates of the different LMSs and (13)C NMR spectroscopy results for treated TMP fibers were obtained for qualitative and quantitative analysis of lignin activation. The results show that reactions were most effective within the first 30 min of incubation. Oxygen consumption was fastest and highest for the LMS using HBA. (13)C NMR spectroscopy indicated the highest decrease of aromatic groups in the wood fiber lignin with this LMS. The data correlated well with the quality of the MDF. The required enzymatic reaction times allowed direct integration of the LMS into standard MDF production techniques. The results indicate that application of LMSs has a high potential for environmentally friendly MDF production. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Computational Analysis of AMPK-Mediated Neuroprotection Suggests Acute Excitotoxic Bioenergetics and Glucose Dynamics Are Regulated by a Minimal Set of Critical Reactions.

    Niamh M C Connolly

    Full Text Available Loss of ionic homeostasis during excitotoxic stress depletes ATP levels and activates the AMP-activated protein kinase (AMPK, re-establishing energy production by increased expression of glucose transporters on the plasma membrane. Here, we develop a computational model to test whether this AMPK-mediated glucose import can rapidly restore ATP levels following a transient excitotoxic insult. We demonstrate that a highly compact model, comprising a minimal set of critical reactions, can closely resemble the rapid dynamics and cell-to-cell heterogeneity of ATP levels and AMPK activity, as confirmed by single-cell fluorescence microscopy in rat primary cerebellar neurons exposed to glutamate excitotoxicity. The model further correctly predicted an excitotoxicity-induced elevation of intracellular glucose, and well resembled the delayed recovery and cell-to-cell heterogeneity of experimentally measured glucose dynamics. The model also predicted necrotic bioenergetic collapse and altered calcium dynamics following more severe excitotoxic insults. In conclusion, our data suggest that a minimal set of critical reactions may determine the acute bioenergetic response to transient excitotoxicity and that an AMPK-mediated increase in intracellular glucose may be sufficient to rapidly recover ATP levels following an excitotoxic insult.

  9. 2-Hydroxy-3-methoxybenzoic acid attenuates mast cell-mediated allergic reaction in mice via modulation of the FcεRI signaling pathway.

    Kim, Yeon-Yong; Je, In-Gyu; Kim, Min Jong; Kang, Byeong-Cheol; Choi, Young-Ae; Baek, Moon-Chang; Lee, Byungheon; Choi, Jin Kyeong; Park, Hae Ran; Shin, Tae-Yong; Lee, Soyoung; Yoon, Seung-Bin; Lee, Sang-Rae; Khang, Dongwoo; Kim, Sang-Hyun


    Mast cells are important effector cells in immunoglobulin (Ig) E-mediated allergic reactions such as asthma, atopic dermatitis and rhinitis. Vanillic acid, a natural product, has shown anti-oxidant and anti-inflammatory activities. In the present study, we investigated the anti-allergic inflammatory effects of ortho-vanillic acid (2-hydroxy-3-methoxybenzoic acid, o-VA) that was a derivative of vanillic acid isolated from Amomum xanthioides. In mouse anaphylaxis models, oral administration of o-VA (2, 10, 50 mg/kg) dose-dependently attenuated ovalbumin-induced active systemic anaphylaxis and IgE-mediated cutaneous allergic reactions such as hypothermia, histamine release, IgE production and vasodilation; administration of o-VA also suppressed the mast cell degranulator compound 48/80-induced anaphylaxis. In cultured mast cell line RBL-2H3 and isolated rat peritoneal mast cells in vitro, pretreatment with o-VA (1-100 μmol/L) dose-dependently inhibited DNP-HSA-induced degranulation of mast cells by decreasing the intracellular free calcium level, and suppressed the expression of pro-inflammatory cytokines TNF-α and IL-4. Pretreatment of RBL-2H3 cells with o-VA suppressed DNP-HSA-induced phosphorylation of Lyn, Syk, Akt, and the nuclear translocation of nuclear factor-κB. In conclusion, o-VA suppresses the mast cell-mediated allergic inflammatory response by blocking the signaling pathways downstream of high affinity IgE receptor (FcεRI) on the surface of mast cells.

  10. [Allergic reactions to transfusion].

    Hergon, E; Paitre, M L; Coeffic, B; Piard, N; Bidet, J M


    Frequent allergic reactions following transfusion are observed. Usually, they are benign but sometimes we observe severe allergic reactions. Adverse reactions may be brought about by least two mechanisms. First, immediate-type hypersensibility reactions due to IgE. Secondly, anaphylactic-type reactions due to interaction between transfused IgA and class specific anti IgA in the recipient's plasma. They are characterized by their severest form (anaphylactic shock). The frequency of severe reactions following the transfusion blood plasma is very low. These transfusion reactions are complement-mediated and kinins-mediated. Prevention of allergic reactions is necessary among blood donors and recipients.

  11. Synthesis, Crystal Structure of Ruthenium 1,2-Naphthoquinone-1-oxime Complex and Its Mediated C-C Coupling Reactions of Terminal Alkynes

    SUN, Ke; WONG, Wing-Tak; LIU, Xiao-Xia; ZHANG, Bao-Yan


    Substituted decarbonylation reaction of ruthenium 1,2-naphthoquinone-1-oxime (1-nqo) complex, cis-, cis-[Ru{ η2-N(O)C10-H6O}2(CO)2] (1), with acetonitrile gave cis-, cis-[Ru { η2-N(O)C10H6O}2(CO)(NCMe)] (2). Complex 2 was fully characterized by 1H NMR, FAB MS, IR spectra and single crystal X-ray analysis. Complex 2 maintains the coordination structure of 1 with the two naphthoquinonic oxygen atoms, as well as the two oximato nitrogen atoms located cis to each other, showing that there is no ligand rearrangement of the 1-nqo ligands during the substitution reaction. The carbonyl group originally trans to the naphthoquinonic oxygen in one 1-nqo ligand is left in its original position [O(5)-Ru-C(1), 174.0(6)°], while the other one originally trans to the oximato group of the other 1-nqo llgand is substituted by NCMe [N(1)-Ru-N(3), 170.6(6)°].This shows that the carbonyl trans to oximato group is more labile than the one trans to naphthoquinonic O atom towards substitution. This is probably due to the comparatively stronger π back bonding from ruthenium metal to the carbonyl group trans to naphthoquinonic O atom, than the one trans to oximato group, resulting in the comparatively weaker Ru-CO bond for the latter and consequently easier replacement of this carbonyl. Selected coupling of phenylacetylene mediated by 2 gave a single trans-dimerization product 3, while 2 mediated coupling reaction of methyl propiolate produced three products:one trans-dimerization product 4 and two cyclotrimeric products 5 and 6.

  12. 1,6-asymmetric induction in boron-mediated aldol reactions: application to a practical total synthesis of (+)-discodermolide.

    Paterson, Ian; Delgado, Oscar; Florence, Gordon J; Lyothier, Isabelle; Scott, Jeremy P; Sereinig, Natascha


    By relying solely on substrate-based stereocontrol, a practical total synthesis of the microtubule-stabilizing anticancer agent (+)-discodermolide has been realized. This exploits a novel aldol bond construction with 1,6-stereoinduction from the boron enolate of (Z)-enone 3 in addition to aldehyde 2. The 1,3-diol 7 is employed as a common building block for the C(1)-C(5), C(9)-C(16), and C(17)-C(24) subunits. [reaction--see text

  13. Miswak mediated green synthesized palladium nanoparticles as effective catalysts for the Suzuki coupling reactions in aqueous media

    Mujeeb Khan


    Full Text Available Green and eco-friendly synthesis of palladium nanoparticles NPs is carried out under facile and eco-friendly conditions using an aqueous solution of Salvadora persica L. (SP root extract (RE as a bioreductant, which is commonly known as Miswak. The as-synthesized Pd NPs were characterized using various spectroscopic and microscopic techniques, including, UV–Vis spectroscopy, FT-IR spectroscopy, XRD, ICP-MS and TEM. Detailed investigations of the Pd NPs have confirmed that the polyphenolic phytomolecules present in the RE of Miswak not only act as a bioreductant by facilitating the reduction and growth of Pd NPs, but they also functionalize the surface of Pd NPs and stabilized them in various solvents. Furthermore, the catalytic activity of the green synthesized Pd NPs was also tested toward the Suzuki coupling reactions of various aryl halides in aqueous media. The as-prepared Pd NPs exhibited superior catalytic activity and reusability for the Suzuki coupling reaction in aqueous and aerobic conditions. The kinetics of the reaction studied by GC revealed that the conversion of various aryl halides to biphenyl takes place in a short time.

  14. Evaluation of multiple-turnover capability of locked nucleic acid antisense oligonucleotides in cell-free RNase H-mediated antisense reaction and in mice.

    Yamamoto, Tsuyoshi; Fujii, Naoko; Yasuhara, Hidenori; Wada, Shunsuke; Wada, Fumito; Shigesada, Naoya; Harada-Shiba, Mariko; Obika, Satoshi


    The multiple-turnover ability of a series of locked nucleic acid (LNA)-based antisense oligonucleotides (AONs) in the RNase H-mediated scission reaction was estimated using a newly developed cell-free reaction system. We determined the initial reaction rates of AONs under multiple-turnover conditions and found that among 24 AONs tested, AONs with melting temperatures (Tm) of 40°C-60°C efficiently elicit multiple rounds of RNA scission. On the other hand, by measuring Tm with two 10-mer RNAs partially complementary to AONs as models of cleaved 5' and 3' fragments of mRNA, we found that AONs require adequate binding affinity for efficient turnover activities. We further demonstrated that the efficacy of a set of 13-mer AONs in mice correlated with their turnover efficiency, indicating that the intracellular situation where AONs function is similar to multiple-turnover conditions. Our methodology and findings may provide an opportunity to shed light on a previously unknown antisense mechanism, leading to further improvement of the activity and safety profiles of AONs.

  15. Influence of the solvent on the ground- and excited-state buffer-mediated proton-transfer reactions of a xanthenic dye.

    Paredes, Jose M; Crovetto, Luis; Orte, Angel; Alvarez-Pez, Jose M; Talavera, Eva M


    The buffer-mediated proton-transfer reactions of the fluorescent xanthenic derivative 9-[1-(2-Methyl-4-methoxyphenyl)]-6-hydroxy-3H-xanthen-3-one (TG-II) have been studied in different aqueous media. We have employed various buffers to investigate the influence of donor/acceptor systems with different anion and/or cation chemical constituents on the kinetic parameters of proton-transfer. The kinetic parameters were recovered both in the ground-state by means of Fluorescence Lifetime Correlation Spectroscopy (FLCS) and in the excited-state by means of Time Correlated Single Photon Counting (TCSPC) and Global Compartmental Analysis (GCA). Both ground- and excited- deprotonation and protonation recovered rate constants in the presence of either phosphate or acetate buffer as donor/acceptor systems were similar. The presence of Tris-HCl buffer does not promote the excited-state proton-transfer (ESPT) reaction. The results indicate the influence of the ions on the ground-state proton-transfer (GSPT) rates and concomitantly on the ESPT reaction. The proton-transfer rate constants recovered here show a trend correlated with the Hofmeister series or the Marcus classification of ions.

  16. Highly selective and sensitive detection of miRNA based on toehold-mediated strand displacement reaction and DNA tetrahedron substrate.

    Li, Wei; Jiang, Wei; Ding, Yongshun; Wang, Lei


    MicroRNAs (miRNAs) play important roles in a variety of biological processes and have been regarded as tumor biomarkers in cancer diagnosis and prognosis. In this work, a single-molecule counting method for miRNA analysis was proposed based on toehold-mediated strand displacement reaction (SDR) and DNA tetrahedron substrate. Firstly, a specially designed DNA tetrahedron was assembled with a hairpin at one of the vertex, which has an overhanging toehold domain. Then, the DNA tetrahedron was immobilized on the epoxy-functional glass slide by epoxy-amine reaction, forming a DNA tetrahedron substrate. Next, the target miRNA perhybridized with the toehold domain and initiated a strand displacement reaction along with the unfolding of the hairpin, realizing the selective recognization of miRNA. Finally, a biotin labeled detection DNA was hybridized with the new emerging single strand and the streptavidin coated QDs were used as fluorescent probes. Fluorescent images were acquired via epi-fluorescence microscopy, the numbers of fluorescence dots were counted one by one for quantification. The detection limit is 5 fM, which displayed an excellent sensitivity. Moreover, the proposed method which can accurately be identified the target miRNA among its family members, demonstrated an admirable selectivity. Furthermore, miRNA analysis in total RNA samples from human lung tissues was performed, suggesting the feasibility of this method for quantitative detection of miRNA in biomedical research and early clinical diagnostics.

  17. Developing single-molecule TPM experiments for direct observation of successful RecA-mediated strand exchange reaction.

    Fan, Hsiu-Fang; Cox, Michael M; Li, Hung-Wen


    RecA recombinases play a central role in homologous recombination. Once assembled on single-stranded (ss) DNA, RecA nucleoprotein filaments mediate the pairing of homologous DNA sequences and strand exchange processes. We have designed two experiments based on tethered particle motion (TPM) to investigate the fates of the invading and the outgoing strands during E. coli RecA-mediated pairing and strand exchange at the single-molecule level in the absence of force. TPM experiments measure the tethered bead Brownian motion indicative of the DNA tether length change resulting from RecA binding and dissociation. Experiments with beads labeled on either the invading strand or the outgoing strand showed that DNA pairing and strand exchange occurs successfully in the presence of either ATP or its non-hydrolyzable analog, ATPγS. The strand exchange rates and efficiencies are similar under both ATP and ATPγS conditions. In addition, the Brownian motion time-courses suggest that the strand exchange process progresses uni-directionally in the 5'-to-3' fashion, using a synapse segment with a wide and continuous size distribution.

  18. A Practical Modeling Approach for NAPL Dissolution Kinetics, Microbially-Mediated Redox Reactions and Aquifer-Aquitard Diffusion to Assess Remedial Options

    Parker, J.; Kim, U.; Widdowson, M.; Chappel, F.


    Explicit modeling of contaminant dissolution from heterogeneously distributed NAPL sources, microbial growth and reaction kinetics, and diffusion into or out of low permeability layers pose significant difficulties. These include the need to estimate a large number of parameters, which may subject to great uncertainty due to inverse problem ill-posedness given limited data, and to a lesser extent, the large computational effort that may be required to solve a rigorously formulated problem. An upscaled model for NAPL dissolution kinetics is utilized in the present study based on previous work, with extentions to consider concurrent effects of residual DNAPL and pools or lenses and to consider multi-component NAPL mixtures. An approach is presented to model microbially-mediated redox reactions subject to the assumption that microbial growth and reaction rates are primarily limited by transport processes rather than by microbial kinetics at time and space scales relevant for many remediation problems. The simplified model requires only stoichiometric coefficients for electron donor and electron acceptor half-reactions and the fraction of electron donor needed for cell synthesis. Contaminant diffusion into low permeability layers and subsequent back-diffusion is approximated as a first-order mass transfer problem with an effective mass transfer coefficient computed from aquifer-aquitard properties by equating second moments of diffusion and mass transfer solutions. Accuracy of the simplified model formulation is evaluated for a hypothetical problem involving a DNAPL source consisting of a mixture of TCE and Stoddard solvent with background dissolved organic carbon, oxygen and sulfate in groundwater for 40 years followed by injection of vegetable oil as a supplemental electron donor to enhance reductive dechlorination. The simplified solution is compared to numerical results that consider multi-species Monod kinetics with explicit treatment of back-diffusion.

  19. Mn(2+)-mediated homogeneous Fenton-like reaction of Fe(III)-NTA complex for efficient degradation of organic contaminants under neutral conditions.

    Li, Yifan; Sun, Jianhui; Sun, Sheng-Peng


    In this work, we report a novel Mn(2+)-mediated Fenton-like process based on Fe(III)-NTA complex that is super-efficient at circumneutral pH range. Kinetics experiments showed that the presence of Mn(2+) significantly enhanced the effectiveness of Fe(III)-NTA complex catalyzed Fenton-like reaction. The degradation rate constant of crotamiton (CRMT), a model compound, by the Fe(III)- NTA_Mn(2+) Fenton-like process was at least 1.6 orders of magnitude larger than that in the absence of Mn(2+). Other metal ions such as Ca(2+), Mg(2+), Co(2+) and Cu(2+) had no impacts or little inhibitory effect on the Fe(III)-NTA complex catalyzed Fenton-like reaction. The generation of hydroxyl radical (HO) and superoxide radical anion (O2(-)) in the Fe(III)-NTA_Mn(2+) Fenton-like process were suggested by radicals scavenging experiments. The degradation efficiency of CRMT was inhibited significantly (approximately 92%) by the addition of HO scavenger 2-propanol, while the addition of O2(-) scavenger chloroform resulted in 68% inhibition. Moreover, the results showed that other chelating agents such as EDTA- and s,s-EDDS-Fe(III) catalyzed Fenton-like reactions were also enhanced significantly by the presence of Mn(2+). The mechanism involves an enhanced generation of O2(-) from the reactions of Mn(2+)-chelates with H2O2, indirectly promoting the generation of HO by accelerating the reduction rate of Fe(III)-chelates to Fe(II)- chelates. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. A smart hydrogel-based time bomb triggers drug release mediated by pH-jump reaction

    Prapatsorn Techawanitchai, Naokazu Idota, Koichiro Uto, Mitsuhiro Ebara and Takao Aoyagi


    Full Text Available We demonstrate a timed explosive drug release from smart pH-responsive hydrogels by utilizing a phototriggered spatial pH-jump reaction. A photoinitiated proton-releasing reaction of o-nitrobenzaldehyde (o-NBA was integrated into poly(N-isopropylacrylamide-co-2-carboxyisopropylacrylamide (P(NIPAAm-co-CIPAAm hydrogels. o-NBA-hydrogels demonstrated the rapid release of protons upon UV irradiation, allowing the pH inside the gel to decrease to below the pKa value of P(NIPAAm-co-CIPAAm. The generated protons diffused gradually toward the non-illuminated area, and the diffusion kinetics could be controlled by adjusting the UV irradiation time and intensity. After irradiation, we observed the enhanced release of entrapped L-3,4-dihydroxyphenylalanine (DOPA from the gels, which was driven by the dissociation of DOPA from CIPAAm. Local UV irradiation also triggered the release of DOPA from the non-illuminated area in the gel via the diffusion of protons. Conventional systems can activate only the illuminated region, and their response is discontinuous when the light is turned off. The ability of the proposed pH-jump system to permit gradual activation via proton diffusion may be beneficial for the design of predictive and programmable devices for drug delivery.

  1. Chimeric Antibody-Binding Vitreoscilla Hemoglobin (VHb Mediates Redox-Catalysis Reaction: New Insight into the Functional Role of VHb

    Yaneenart Suwanwong, Malin Kvist, Chartchalerm Isarankura-Na-Ayudhya, Natta Tansila, Leif Bulow, Virapong Prachayasittikul


    Full Text Available Experimentation was initiated to explore insight into the redox-catalysis reaction derived from the heme prosthetic group of chimeric Vitreoscilla hemoglobin (VHb. Two chimeric genes encoding chimeric VHbs harboring one and two consecutive sequences of Fc-binding motif (Z-domain were successfully constructed and expressed in E. coli strain TG1. The chimeric ZVHb and ZZVHb were purified to a high purity of more than 95% using IgG-Sepharose affinity chromatography. From surface plasmon resonance, binding affinity constants of the chimeric ZVHb and ZZVHb to human IgG were 9.7 x 107 and 49.1 x 107 per molar, respectively. More importantly, the chimeric VHbs exhibited a peroxidase-like activity determined by activity staining on native PAGE and dot blotting. Effects of pH, salt, buffer system, level of peroxidase substrate and chromogen substrate were determined in order to maximize the catalytic reaction. From our findings, the chimeric VHbs displayed their maximum peroxidase-like activity at the neutral pH (~7.0 in the presence of high concentration (20-40 mM of hydrogen peroxide. Under such conditions, the detection limit derived from the calibration curve was at 250 ng for the chimeric VHbs, which was approximately 5-fold higher than that of the horseradish peroxidase. These findings reveal the novel functional role of Vitreoscilla hemoglobin indicating a high trend of feasibility for further biotechnological and medical applications.

  2. Role of cluster size and substrate in the gas phase CC bond coupling reactions of allyl halides mediated by Agn+ and Agn-1H+ cluster cations

    Wang, Farrah Qiuyun; Khairallah, George N.; O'Hair, Richard A. J.


    Previous studies have demonstrated that the silver hydride cluster cation Ag4H+ promotes CC bond coupling of allylbromide [G.N. Khairallah, R.A.J. O'Hair, Angewandte Chemie International Edition 44 (2005) 728]. Here the influence of both the nature and the size of the silver cluster cation and the substrate on CC bond coupling are examined. Thus each of the cations Ag2H+, Ag4H+, Ag3+, and Ag5+ were allowed to react with three different halides: allyl chloride, allyl bromide and allyl iodide. No CC bond coupling is observed in the reactions of the cluster cations with allyl chloride. There are four main reaction sequences that result in CC bond coupling for allyl bromide and allyl iodide mediated by Agn+ and Agn-1H+ clusters: (i) A sequence involving the reactions of silver cluster cations with two molecules of C3H5X: Agn+ --> Agn(C3H5X)+ --> AgnX2+. This only occurs in the cases of: n = 3 and X = I; n = 5 and X = Br. (ii) A sequence involving the reactions of silver cluster cations with two molecules of C3H5X via an organometallic intermediate: Agn+ --> Agn-1(C3H5)+ --> Agn-1X+. This only occurs in the cases of: n = 5 and X = Br and I. (iii) A sequence involving the reactions of silver hydride cluster cations with three molecules of C3H5X: Agn-1H+ --> Agn-1X+ --> Agn-1X(C3H5X)+ --> Ag(C3H5)2+ and Agn-1X3+. This only occurs in the cases of: n = 5 and X = Br and I. (iv) A sequence involving the reactions of silver hydride cluster cations with three molecules of C3H5X via an organometallic intermediate: Agn-1H+ --> Agn-1X+ --> Agn-3(C3H5)+ --> Ag(C3H5)2+ and Agn-3X+. This only occurs in the cases of: n = 5 and X = I.

  3. Loop mediated isothermal amplification assay using hydroxy naphthol blue, conventional polymerase chain reaction and real-time PCR in the diagnosis of intraocular tuberculosis.

    Balne, P K; Basu, S; Rath, S; Barik, M R; Sharma, S


    This study is a comparative evaluation (Chi-square test) of a closed tube loop mediated isothermal amplification assay using hydroxy naphthol blue dye (HNB-LAMP), real-time polymerase chain reaction (PCR) and conventional PCR in the diagnosis of intraocular tuberculosis. Considering clinical presentation as the gold standard in 33 patients, the sensitivity of HNB-LAMP assay (75.8%) was higher (not significant, P value 0.2) than conventional PCR (57.6%) and lower than real-time PCR (90.9%). Specificity was 100% by all three methods. No amplification was observed in negative controls (n = 20) by all three methods. The cost of the HNB-LAMP assay was Rs. 500.00 and it does not require thermocycler, therefore, it can be used as an alternative to conventional PCR in resource-poor settings.

  4. Loop mediated isothermal amplification assay using hydroxy naphthol blue, conventional polymerase chain reaction and real-time PCR in the diagnosis of intraocular tuberculosis

    P K Balne


    Full Text Available This study is a comparative evaluation (Chi-square test of a closed tube loop mediated isothermal amplification assay using hydroxy naphthol blue dye (HNB-LAMP, real-time polymerase chain reaction (PCR and conventional PCR in the diagnosis of intraocular tuberculosis. Considering clinical presentation as the gold standard in 33 patients, the sensitivity of HNB-LAMP assay (75.8% was higher (not significant, P value 0.2 than conventional PCR (57.6% and lower than real-time PCR (90.9%. Specificity was 100% by all three methods. No amplification was observed in negative controls (n = 20 by all three methods. The cost of the HNB-LAMP assay was Rs. 500.00 and it does not require thermocycler, therefore, it can be used as an alternative to conventional PCR in resource-poor settings.

  5. Giardia and Cryptosporidium spp. dissemination during wastewater treatment and comparative detection via immunofluorescence assay (IFA), nested polymerase chain reaction (nested PCR) and loop mediated isothermal amplification (LAMP).

    Gallas-Lindemann, Carmen; Sotiriadou, Isaia; Plutzer, Judit; Noack, Michael J; Mahmoudi, Mohammad Reza; Karanis, Panagiotis


    Environmental water samples from the Lower Rhine area in Germany were investigated via immunofluorescence assays (IFAs), nested polymerase chain reaction (nested PCR) and loop-mediated isothermal amplification (LAMP) to detect the presence of Giardia spp. (n=185) and Cryptosporidium spp. (n=227). The samples were concentrated through filtration or flocculation, and oocysts were purified via centrifugation through a sucrose density gradient. For all samples, IFA was performed first, followed by DNA extraction for the nested PCR and LAMP assays. Giardia cysts were detected in 105 samples (56.8%) by IFA, 62 samples (33.5%) by nested PCR and 79 samples (42.7%) by LAMP. Cryptosporidium spp. were detected in 69 samples (30.4%) by IFA, 95 samples (41.9%) by nested PCR and 99 samples (43.6%) by LAMP. According to these results, the three detection methods are complementary for monitoring Giardia and Cryptosporidium in environmental waters.

  6. Oxidative Cyclization of Sulfamate Esters Using NaOCl - A Metal-Mediated Hoffman-Löffler Freytag Reaction.

    Zalatan, David N; Du Bois, J


    Intramolecular C-H amination with sulfamate esters occurs under the action of dinuclear Rh catalysts and iodine(III) oxidants, and has recently emerged as a powerful tool for synthesis. Insights gained through mechanistic studies of this process suggest that other terminal oxidants, including common halogenating agents such as NaOCl, could function to promote the cyclization reaction. Results described in this report demonstrate that the combination of NaOCl and 3 mol% Rh(2)(oct)(4) is effective in select cases for converting sulfamate substrates to the corresponding [1,2,3]-oxathiazinane-2,2-dioxide heterocycles. The mechanism for C-H functionalization, however, is distinct from that induced by hypervalent iodine reagents and likely involves the intermediacy of an N-centered radical.

  7. Oxidative Cyclization of Sulfamate Esters Using NaOCl – A Metal-Mediated Hoffman-Löffler Freytag Reaction

    Zalatan, David N.; Du Bois, J.


    Intramolecular C–H amination with sulfamate esters occurs under the action of dinuclear Rh catalysts and iodine(III) oxidants, and has recently emerged as a powerful tool for synthesis. Insights gained through mechanistic studies of this process suggest that other terminal oxidants, including common halogenating agents such as NaOCl, could function to promote the cyclization reaction. Results described in this report demonstrate that the combination of NaOCl and 3 mol% Rh2(oct)4 is effective in select cases for converting sulfamate substrates to the corresponding [1,2,3]-oxathiazinane-2,2-dioxide heterocycles. The mechanism for C–H functionalization, however, is distinct from that induced by hypervalent iodine reagents and likely involves the intermediacy of an N-centered radical. PMID:19319207

  8. Discriminating complement-mediated acute transfusion reaction for type O+ red blood cells transfused into a B+ recipient with the complement hemolysis using human erythrocytes (CHUHE) assay.

    Cunnion, Kenji M; Hair, Pamela S; Krishna, Neel K; Whitley, Pamela H; Goldberg, Corinne L; Fadeyi, Emmanuel A; Maes, Lanne Y


    A patient with B+ sickle cell disease received 3 units of red blood cells (RBCs) from two O+ donors and developed fever and hypotension after the first unit, consistent with an acute transfusion reaction (ATR). Anti-B titers in plasma from each O+ donor were markedly elevated and nondiscriminatory. In order to evaluate the potential for the transfused units to produce complement-mediated hemolysis of B+ RBCs, hemolytic complement testing was performed. Plasma from each donor was diluted in veronal buffer and incubated with B+ RBCs, and free hemoglobin was measured by spectrophotometer in the complement hemolysis using human erythrocytes (CHUHE) assay. Peptide inhibitor of complement C1 (PIC1) was used to confirm antibody-initiated complement pathway activation. A 96-fold difference (p = 0.014) in hemolysis was measured between plasma samples from the two O+ donors using the CHUHE assay. The extremely high degree of hemolysis produced by the one plasma was inhibited by PIC1 in a dose-dependent manner. These results indicate that hemolytic complement testing with the CHUHE assay can be used to assess the risk of antibody-initiated, complement-mediated hemolysis from a transfusion beyond what can be achieved with antibody titers alone. © 2016 AABB.

  9. The mediation reaction between the external couple Ferri/Ferrocyanide and Os(II) bipyridile poly-vinylpyridile films coated onto glassy carbon electrodes

    Ybarra, Gabriel; Moina, Carlos [Centro de Investigacion sobre Electrodeposicion y Procesos Superficiales, Instituto Nacional de Tecnologia Industrial, CC 157, 1650 San Martin (Argentina); Florit, M. Ines [INIFTA, Facultad de Ciencias Exactas, UNLP, Suc. 4, CC 16, 1900 La Plata (Argentina); Posadas, Dionisio [INIFTA, Facultad de Ciencias Exactas, UNLP, Suc. 4, CC 16, 1900 La Plata (Argentina)], E-mail:


    The oxidation-reduction of the Ferri/Ferrocyanide couple in solution onto modified glassy carbon Rotating Disk Electrodes (RDE) covered by Os(II) bipyridile poly-vinylpyridile (OsBPP) polymer was studied at room temperature. Steady state polarization curves were carried out as a function of the rotation speed, the polymer thickness and the concentration of redox centers within the polymer. This system has the characteristic that the formal redox potentials of both the external redox couple (E{sup 0}'(Fe(CN){sub 6}{sup 3-/4-}) = + 0.225 V vs. SCE) and the mediator polymer (E{sup 0}'(OsBPP) = 0.260 V vs. SCE) lie very close. It is demonstrated that diffusion of the Ferri/Ferrocyanide inside the polymer can be ruled out. Since the processes of charge transfer at the metal/polymer and the mediating reaction are fast, the experimental results can be interpreted in terms of a kinetics in which the charge transport in the polymer or the diffusion in the solution may be the rate determining step, according to the experimental conditions. A simple model is considered that allows interpreting the experimental results quantitatively. Application of this model allows the determination of the diffusion coefficient of the electrons within the film, D{sub e} {approx} 10{sup -10} cm{sup 2} s{sup -1}.

  10. The Influence of Receptor-Mediated Interactions on Reaction-Diffusion Mechanisms of Cellular Self-organisation

    Klika, Václav


    Understanding the mechanisms governing and regulating self-organisation in the developing embryo is a key challenge that has puzzled and fascinated scientists for decades. Since its conception in 1952 the Turing model has been a paradigm for pattern formation, motivating numerous theoretical and experimental studies, though its verification at the molecular level in biological systems has remained elusive. In this work, we consider the influence of receptor-mediated dynamics within the framework of Turing models, showing how non-diffusing species impact the conditions for the emergence of self-organisation. We illustrate our results within the framework of hair follicle pre-patterning, showing how receptor interaction structures can be constrained by the requirement for patterning, without the need for detailed knowledge of the network dynamics. Finally, in the light of our results, we discuss the ability of such systems to pattern outside the classical limits of the Turing model, and the inherent dangers involved in model reduction. © 2011 Society for Mathematical Biology.

  11. Integrity of the plasma membrane, the acrosomal membrane, and the mitochondrial membrane potential of sperm in Nelore bulls from puberty to sexual maturity

    L.S.L.S. Reis


    Full Text Available ABSTRACT This study evaluated the plasma membrane integrity, acrosomal membrane integrity, and mitochondrial membrane potential of Nelore bull sperm from early puberty to early sexual maturity and their associations with sperm motility and vigor, the mass motility of the spermatozoa (wave motion, scrotal circumference, and testosterone. Sixty Nelore bulls aged 18 to 19 months were divided into four lots (n=15 bulls/lot and evaluated over 280 days. Semen samples, collected every 56 days by electroejaculation, were evaluated soon after collection for motility, vigor and wave motion under an optical microscope. Sperm membrane integrity, acrosomal integrity, and mitochondrial activity were evaluated under a fluorescent microscope using probe association (FITC-PSA, PI, JC-1, H342. The sperm were classified into eight integrity categories depending on whether they exhibited intact or damaged membranes, an intact or damaged acrosomal membrane, and high or low mitochondrial potential. The results show that bulls have a low amount of sperm with intact membranes at puberty, and the sperm show low motility, vigor, and wave motion; however, in bulls at early sexual maturity, the integrity of the sperm membrane increased significantly. The rate of sperm membrane damage was negatively correlated with motility, vigor, wave motion, and testosterone in the bulls, and a positive correlation existed between sperm plasma membrane integrity and scrotal circumference. The integrity of the acrosomal membrane was not influenced by puberty. During puberty and into early sexual maturity, bulls show low sperm mitochondrial potential, but when bulls reached sexual maturity, high membrane integrity with high mitochondrial potential was evident.

  12. The tert-butoxyl radical mediated hydrogen atom transfer reactions of the Parkinsonian proneurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and selected tertiary amines.

    Suleman, N Kamrudin; Flores, Joey; Tanko, James M; Isin, Emre Mehmet; Castagnoli, Neal


    Previous studies have shown that the hydrogen atom transfer (HAT) reactions of tert-butoxyl radical from the Parkinsonian proneurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) occur with low selectivity at the allylic and non-allylic alpha-C-H positions. In this paper, we report a more comprehensive regiochemical study on the reactivity of the tert-butoxyl radical as well as on the associated primary kinetic deuterium isotope effects for the various hydrogen atom abstractions of MPTP. In addition, the results of a computational study to estimate the various C-H bond dissociation energies of MPTP are presented. The results of the present study show the allylic/non-allylic selectivity is approximately 73:21. The behavior of the tert-butoxyl radical mediated oxidation of MPTP contrasts with this reaction as catalyzed by monoamine oxidase B (MAO-B) that occurs selectively at the allylic alpha-carbon. These observations lead to the conclusion that the tert-butoxyl radical is not a good chemical model for the MAO-B-catalyzed bioactivation of MPTP.

  13. Fenton reaction-mediated fluorescence quenching of N-acetyl-L-cysteine-protected gold nanoclusters: analytical applications of hydrogen peroxide, glucose, and catalase detection.

    Deng, Hao-Hua; Wu, Gang-Wei; He, Dong; Peng, Hua-Ping; Liu, Ai-Lin; Xia, Xing-Hua; Chen, Wei


    Given the importance of hydrogen peroxide (H2O2) in many biological processes and its wide application in various industries, the demand for sensitive, accurate, and economical H2O2 sensors is high. In this study, we used Fenton reaction-stimulated fluorescence quenching of N-acetyl-L-cysteine-protected gold nanoclusters (NAC-AuNCs) as a reporter system for the determination of H2O2. After the experimental conditions were optimized, the sensing platform enabled the analysis of H2O2 with a limit of detection (LOD) as low as 0.027 μM. As the glucose oxidase cascade leads to the generation of H2O2 and catalase catalyzes the decomposition of H2O2, these two biocatalytic procedures can be probed by the Fenton reaction-mediated quenching of NAC-AuNCs. The LOD for glucose was found to be 0.18 μM, and the linear range was 0.39-27.22 μM. The LOD for catalase was 0.002 U mL(-1), and the linear range was 0.01-0.3 U mL(-1). Moreover, the proposed sensing methods were successfully applied for human serum glucose detection and the non-invasive determination of catalase activity in human saliva, demonstrating their great potential for practical applications.

  14. Highly enantioselective cross-aldol reactions of acetaldehyde mediated by a dual catalytic system operating under site isolation.

    Fan, Xinyuan; Rodríguez-Escrich, Carles; Wang, Shoulei; Sayalero, Sonia; Pericàs, Miquel A


    Polystyrene-supported (PS) diarylprolinol catalysts 1 a (Ar = phenyl) and 1 b (Ar = 3,5-bis(trifluoromethyl)phenyl) have been developed. Operating under site-isolation conditions, PS-1 a/1 b worked compatibly with PS-bound sulfonic acid catalyst 2 to promote deoligomerization of paraldehyde and subsequent cross-aldol reactions of the resulting acetaldehyde in one pot, affording aldol products in high yields with excellent enantioselectivities. The effect of water on the performance of the catalytic system has been studied and its optimal amount (0.5 equiv) has been determined. The dual catalytic system (1/2) allows repeated recycling and reuse (10 cycles). The potential of this methodology is demonstrated by a two-step synthesis of a phenoperidine analogue (68% overall yield; 98% ee) and by the preparation of highly enantioenriched 1,3-diols 4 and 3-methylamino-1-arylpropanols 5, key intermediates in the synthesis of a variety of druglike structures. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. In vitro effects of nonylphenol on motility, mitochondrial, acrosomal and chromatin integrity of ram and boar spermatozoa.

    Uguz, C; Varisli, O; Agca, C; Evans, T; Agca, Y


    The objective of this study was to determine the effects of nonylphenol (NP) on viability of ram and boar sperm in vitro. Ram or boar spermatozoa were exposed to 1, 10, 100, 250 and 500 μg NP ml(-1) for 1, 2, 3 or 4 h. Computer-assisted sperm motility analysis (CASA) system was used to evaluate sperm motility characteristics. Flow cytometry was used to determine mitochondrial membrane potential (MMP) and chromatin integrity, while epifluorescent microscopy was used to determine sperm acrosomal status. Exposure of both species spermatozoa to 250 and 500 μg NP ml(-1) was detrimental to progressive motility (P boar spermatozoa with high MMP declined drastically after exposures to ≥250 μg ml(-1) NP (P boar spermatozoa and 10 μg ml(-1) NP for ram spermatozoa. These data show adverse effects of NP on ram and boar spermatozoa and thus its potential harmful effects on male reproduction as NP is found in fruits, vegetables, human milk, fish and livestock products.


    M R Nowroozi


    Full Text Available "nVasectomy is one of the extensively used methods of contraception in family planning programs. Antisperm antibodies (ASA develop after vasectomy which can result in auto-immune male infertility. The precise sperm antigens involved in the autoimmune response are still poorly defined, therefore we determined the circulating ASA and identified relevant sperm antigens based on localization of binding sites of ASA to sperm cell antigens, using a rapid, inexpensive and clinically relevant assay in vasectomized men. Results showed that 2.5% of men had ASA at the time of vasectomy, whereas 53.5% of the study population subsequently developed ASA. The numbers of men with circulating ASA increased significantly for the first three months after vasectomy. These antibodies were distinguishable into three groups based on their bindings to different sites of sperm cell antigens including against acrosome and tail in 67.56% and 10.8%, respectively; 21.6% of subjects had antibody to the other parts of the sperm cell antigens. The results of this study are discussed in terms of an autoimmune response against sperm antigens and development of ASA.

  17. Effect of reaction conditions on methyl red degradation mediated by boron and nitrogen doped TiO{sub 2}

    Galenda, A., E-mail: [CNR-IENI, Istituto per l’Energetica e le Interfasi, Corso Stati Uniti, 4 35127 Padova (Italy); Crociani, L.; Habra, N. El; Favaro, M. [CNR-IENI, Istituto per l’Energetica e le Interfasi, Corso Stati Uniti, 4 35127 Padova (Italy); Natile, M.M. [CNR-IENI, Istituto per l’Energetica e le Interfasi, Dipartimento di Scienze Chimiche, Università di Padova, via F. Marzolo, 1 35131 Padova (Italy); Rossetto, G. [CNR-IENI, Istituto per l’Energetica e le Interfasi, Corso Stati Uniti, 4 35127 Padova (Italy)


    Highlights: • Boron and/or nitrogen-doped TiO{sub 2} for photocatalytic wastewater treatment. • Methyl red degradation/mineralisation as a function of pH, acids and dopants. • Adsorption time influence on photocatalytic process. • Recovery of worn-out catalyst. - Abstract: Nowadays the employment of renewable and sustainable energy sources, and solar light as main option, becomes an urgent need. Photocatalytic processes received great attention in wastewater treatment due to their cheapness, environmental compatibility and optimal performances. Despite the general low selectivity of the photocatalysts, an accurate optimisation of the operational parameters needs to be carried out in order to maximise the process yield. Because of this reason, the present contribution aims to deepen either the knowledge in boron and/or nitrogen doped TiO{sub 2}-based systems and their employment in methyl red removal from aqueous solutions. The samples were obtained by coprecipitation and characterised by XRD, SEM, BET specific surface area, UV–vis and XPS techniques. The catalytic activity was for the first time carefully evaluated with respect to methyl red photodegradation in different conditions as a function of working pH, counter-ions and pre-adsorption time. An ad-hoc study was performed on the importance of the pre-adsorption of the dye, suggesting that an extended adsorption is useless for the catalyst photoactivity, while a partial coverage is preferable. The photocatalytic tests demonstrate the positive influence of boron doping in photo-activated reactions and the great importance of the operational parameters with respect to the simple methyl red bleaching rather than the overall pollutant mineralisation. It is proved, indeed, that different working pH, acidifying means and substrate pre-adsorption time can enhance or limit the catalyst performances with respect to the complete pollutant degradation rather than its partial breakage.

  18. Effect of reaction conditions on methyl red degradation mediated by boron and nitrogen doped TiO2

    Galenda, A.; Crociani, L.; Habra, N. El; Favaro, M.; Natile, M. M.; Rossetto, G.


    Nowadays the employment of renewable and sustainable energy sources, and solar light as main option, becomes an urgent need. Photocatalytic processes received great attention in wastewater treatment due to their cheapness, environmental compatibility and optimal performances. Despite the general low selectivity of the photocatalysts, an accurate optimisation of the operational parameters needs to be carried out in order to maximise the process yield. Because of this reason, the present contribution aims to deepen either the knowledge in boron and/or nitrogen doped TiO2-based systems and their employment in methyl red removal from aqueous solutions. The samples were obtained by coprecipitation and characterised by XRD, SEM, BET specific surface area, UV-vis and XPS techniques. The catalytic activity was for the first time carefully evaluated with respect to methyl red photodegradation in different conditions as a function of working pH, counter-ions and pre-adsorption time. An ad-hoc study was performed on the importance of the pre-adsorption of the dye, suggesting that an extended adsorption is useless for the catalyst photoactivity, while a partial coverage is preferable. The photocatalytic tests demonstrate the positive influence of boron doping in photo-activated reactions and the great importance of the operational parameters with respect to the simple methyl red bleaching rather than the overall pollutant mineralisation. It is proved, indeed, that different working pH, acidifying means and substrate pre-adsorption time can enhance or limit the catalyst performances with respect to the complete pollutant degradation rather than its partial breakage.

  19. Operando Solid-State NMR Observation of Solvent-Mediated Adsorption-Reaction of Carbohydrates in Zeolites

    Qi, Long; Alamillo, Ricardo; Elliott, William A.; Andersen, Amity; Hoyt, David W.; Walter, Eric D.; Han, Kee Sung; Washton, Nancy M.; Rioux, Robert M.; Dumesic, James A.; Scott, Susannah L.


    In the liquid-phase catalytic processing of molecules using heterogeneous catalysts - an important strategy for obtaining renewable chemicals from biomass - many of the key reactions occur at solid-liquid interfaces. In particular, glucose isomerization occurs when the glucose is adsorbed in the micropores of a zeolite catalyst. Since solvent molecules are coadsorbed, the catalytic activity depends strongly and often nonmonotonically on the solvent composition. For glucose isomerization catalyzed by NaX and NaY zeolites, there is an initial steep decline when water is mixed with a small amount of the organic cosolvent γ-valerolactone (GVL), followed by a dramatic and surprising recovery as the GVL content in the mixed solvent increases. Here we elucidate the origin of this complex solvent effect using operando solid-state NMR spectroscopy. The glucopyranose tautomers immobilized in the zeolite pores were observed and their transformations into fructose and mannose followed in real time. The microheterogeneity of the solvent system, manifested by a nonmonotonic trend in the mixing enthalpy, influences the mobility and adsorption behavior of the carbohydrates, water, and GVL, which were studied using pulsed-field gradient (PFG) NMR diffusivity measurements. At low GVL concentrations, glucose is depleted in the zeolite pores relative to the solution phase and changes in the local structure of coadsorbed water serve to further suppress the isomerization rate. At higher GVL concentrations, this lower intrinsic reactivity is largely compensated by strong glucose partitioning into the pores, resulting in dramatic (up to 32×) enhancements in the local sugar concentration at the solid-liquid interface.

  20. Humoral and Cell-mediated Autoimmune Reactions to Human Acidic Ribosomal P2 Protein in Individuals Sensitized to Aspergillus fumigatus P2 Protein

    Mayer, Christina; Appenzeller, Ulrich; Seelbach, Heike; Achatz, Gernot; Oberkofler, Hannes; Breitenbach, Michael; Blaser, Kurt; Crameri, Reto


    A panel of cDNAs encoding allergenic proteins was isolated from an Aspergillus fumigatus cDNA library displayed on the surface of filamentous phage. Solid phase–immobilized serum immunoglobulin E (IgE) from A. fumigatus–allergic individuals was used to enrich phage displaying IgE-binding molecules. One of the cDNAs encoded a 11.1-kD protein that was identified as acidic ribosomal phosphoprotein type 2 (P2 protein). The allergen, formally termed rAsp f 8, shares >62% sequence identity and >84% sequence homology to corresponding eukaryotic P2 proteins, including human P2 protein. The sequences encoding human and fungal P2 protein were subcloned, expressed in Escherichia coli as His6-tagged fusion proteins, and purified by Ni2+–chelate affinity chromatography. Both recombinant P2 proteins were recognized by IgE antibodies from allergic individuals sensitized to the A. fumigatus P2 protein and elicited strong type 1–specific skin reactions in these individuals. Moreover, human and fungal P2 proteins induced proliferative responses in peripheral blood mononuclear cells of A. fumigatus– allergic subjects sensitized to the fungal P2 protein. These data provide strong evidence for in vitro and in vivo humoral and cell-mediated autoreactivity to human P2 protein in patients suffering from chronic A. fumigatus allergy. PMID:10224291

  1. Quantification and evaluation of kinetic bio-catalytic pathway of horseradish peroxidase in an electron mediated reaction system and its applications in plant extracts

    Krishna, Honnur; Nagaraja, Padmarajaiah; Shivakumar, Anantharaman; Chamaraja, Nelligere A.; Aradhana, Narayan


    The intermolecular coupling of 2,5-dimethoxyaniline (DMA) as mediated electron transfer reaction in presence of H2O2 and peroxidase in acetate buffer of pH 4.2 resulting green colored product having maximum absorption at λmax = 740 nm was investigated by spectrophotometer. Under optimum conditions, linearity range for the quantification of H2O2 was 2.0-288.0 μM and for peroxidase were 0.59-9.46 and 0.443-9.46 nM by kinetic and fixed-time method, respectively. The catalytic efficiency and catalytic power were KeffD = 2.354 × 105 M-1 min-1 and KpowD = 4.59 × 10-4 min-1, respectively. From the plot of d(1/Do) vs d(1/Vo) and d(1/Ho) vs d(1/Vo), Michaelis-Menten constants for DMA and H2O2were found that KmD = 1458 μM and KmHO = 301 μM. Applicability of the method was tested for peroxidase activity in some plant extracts and compared with guaiacol/peroxidase system. Regarding superiority of the method, it is suggested that DMA/peroxidase system can be a better hydrogen donor for HRP assay than guaiacol system as evident from kinetic data.

  2. Identification of region-specific yeast artificial chromosomes using pools of Alu element-mediated polymerase chain reaction probes labeled via linear amplification

    Cole, C.G.; Bobrow, M.; Bentley, D.R.; Dunham, I. (United Medical and Dental Schools of Guy' s and St. Thomas Hospitals, London Bridge, London, England (United Kingdom)); Patel, K.; Shipley, J.; Sheer, D. (Imperial Cancer Research Fund, London (United Kingdom))


    The ability to identify large numbers of yeast artificial chromosomes (YACS) specific to any given genomic region rapidly and efficiently enhances both the construction of clone maps and the isolation of region-specific landmarks (e.g., polymorphic markers). The authors describe a method of preparing region-specific single-stranded hybridization probes from Alu element-mediated polymerase chain reaction (Alu-PCR) products of somatic cell hybrids for YAC library screening. Pools of up to 50 cloned Alu-PCR products from an irradiation-reduced hybrid containing 22q11.2-q13.1 were labeled to high specific activity by linear amplification using a single vector primer. The resulting single-stranded probes were extensively competed to remove repetitive sequences, while retaining the full complexity of the probe. Extensive coverage of the region by YACs using multiple probe pools was demonstrated as many YACs were detected more than once. In situ analysis using chosen YACs confirmed that the clones were specific for the region. Thus, this pooled probe approach constitutes a rapid method to identify large numbers of YACs relevant to a large chromosomal region. 29 refs., 4 figs.

  3. Identification of region-specific yeast artificial chromosomes using pools of Alu element-mediated polymerase chain reaction probes labeled via linear amplification.

    Cole, C G; Patel, K; Shipley, J; Sheer, D; Bobrow, M; Bentley, D R; Dunham, I


    The ability to identify large numbers of yeast artificial chromosomes (YACs) specific to any given genomic region rapidly and efficiently enhances both the construction of clone maps and the isolation of region-specific landmarks (e.g., polymorphic markers). We describe a method of preparing region-specific single-stranded hybridization probes from Alu element-mediated polymerase chain reaction (Alu-PCR) products of somatic cell hybrids for YAC library screening. Pools of up to 50 cloned Alu-PCR products from an irradiation-reduced hybrid containing 22q11.2-q13.1 were labeled to high specific activity by linear amplification using a single vector primer. The resulting single-stranded probes were extensively competed to remove repetitive sequences, while retaining the full complexity of the probe. Extensive coverage of the region by YACs using multiple probe pools was demonstrated as many YACs were detected more than once. In situ analysis using chosen YACs confirmed that the clones were specific for the region. Thus, this pooled probe approach constitutes a rapid method to identify large numbers of YACs relevant to a large chromosomal region.

  4. Quantification and evaluation of kinetic bio-catalytic pathway of horseradish peroxidase in an electron mediated reaction system and its applications in plant extracts.

    Krishna, Honnur; Nagaraja, Padmarajaiah; Shivakumar, Anantharaman; Chamaraja, Nelligere A; Aradhana, Narayan


    The intermolecular coupling of 2,5-dimethoxyaniline (DMA) as mediated electron transfer reaction in presence of H(2)O(2) and peroxidase in acetate buffer of pH 4.2 resulting green colored product having maximum absorption at λ(max)=740 nm was investigated by spectrophotometer. Under optimum conditions, linearity range for the quantification of H(2)O(2) was 2.0-288.0 μM and for peroxidase were 0.59-9.46 and 0.443-9.46 nM by kinetic and fixed-time method, respectively. The catalytic efficiency and catalytic power were K(eff)(D)=2.354 × 10(5)M(-1)min(-1) and K(pow)(D)=4.59 × 10(-4)min(-1), respectively. From the plot of d(1/D(o)) vs d(1/V(o)) and d(1/H(o)) vs d(1/V(o)), Michaelis-Menten constants for DMA and H(2)O(2)were found that K(m)(D)=1,458 μM and [Formula: see text] =301 μM. Applicability of the method was tested for peroxidase activity in some plant extracts and compared with guaiacol/peroxidase system. Regarding superiority of the method, it is suggested that DMA/peroxidase system can be a better hydrogen donor for HRP assay than guaiacol system as evident from kinetic data.

  5. Uvangoletin induces mitochondria-mediated apoptosis in HL-60 cells in vitro and in vivo without adverse reactions of myelosuppression, leucopenia and gastrointestinal tract disturbances.

    Zheng, Zhuanzhen; Qiao, Zhenhua; Gong, Rong; Wang, Yalin; Zhang, Yiqun; Ma, Yanping; Zhang, Li; Lu, Yujin; Jiang, Bo; Li, Guoxia; Dong, Chunxia; Chen, Wenliang


    This study investigated the cytotoxic effect of uvangoletin on HL-60 cells, and the effects of uvangoletin on myelosuppression, leucopenia, gastrointestinal tract disturbances and the possible cytotoxic mechanisms by using CCK-8, flow cytometry, western blot, xenograft, cyclophosphamide-induced leucopenia, copper sulfate-induced emesis and ethanol-induced gastric mucosal lesions assays. The results of CCK-8, flow cytometry and western blot assays indicated that uvangoletin showed the cytotoxic effect on HL-60 cells and induced the apoptosis of HL-60 cells by downregulating the expression levels of anti-apoptotic proteins (Survivin, Bcl-xl and Bcl-2), upregulating the expression levels of pro-apoptotic proteins (Smac, Bax, Bad, c-caspase-3 and c-caspase-9), and promoting the release of cytochrome c from mitochondria to cytoplasm. Further, the results of xenograft assay suggested that uvangoletin inhibited the HL-60-induced tumor growth without adverse effect on body weight of nude mice in vivo by regulating the expression levels of above apoptotic proteins. The results indicated that the reductions of WBCs count and thighbone marrow granulocytes percentage in cyclophosphamide-induced leucopenia assay, the incubation period and number of emesis in copper sulfate-induced emesis assay and the gastric mucosal lesions in ethanol-induced gastric mucosal lesions assay were not exacerbated or reversed by uvangoletin. In conclusion, the research preliminarily indicated that uvangoletin induced apoptosis of HL-60 cells in vitro and in vivo without adverse reactions of myelosuppression, leucopenia and gastrointestinal tract disturbances, and the pro-apoptotic mechanisms may be related to mitochondria-mediated apoptotic pathway.

  6. Endonuclease restriction-mediated real-time polymerase chain reaction: a novel technique for rapid, sensitive and quantitative detection of nucleic-acid sequence

    Yi Wang


    Full Text Available The article reported a novel methodology for real-time PCR analysis of nucleic acids, termed endonuclease restriction-mediated real-time polymerase chain reaction (ET-PCR. Just like PCR, ET-PCR only required one pair of primers. A short sequence (Ss, which was recognized by restriction enzyme BstUI, was attached to the 5’ end of the forward (F or reverse (R PCR primer, and the new F or R primer was named EF or ER. EF/ER was labeled at the 5’ end with a reporter dye and in the middle with a quenching dye. BstUI cleaves the newly synthesized double-stranded terminal sequences (5’ end recognition sequences and their complementary sequences during the extension phase, which separates the reporter molecule from the quenching dye, leading to a gain of fluorescence signal. This process is repeated in each amplification cycle and unaffected the exponential synthesis of the PCR amplification. ET-PCR allowed real-time analysis of single or multiple targets in a single vessel, and provided the reproducible quantitation of nucleic acids. positive results were generated in a relatively short period. The analytical sensitivity and specificity of ETR-PCR were successfully evaluated, detecting down to 250 fg of genomic DNA per tube of target pathogen DNA examined, and the positive results were generated in a relatively short period. Moreover, the practical application of ET-PCR for simultaneous detection of multiple target pathogens was also demonstrated in artificially contaminated blood samples. In conclusion, due to the technique’s simplicity of design, reproducible data and low contamination risk, ET-PCR assay is an appealing alternative to conventional approaches currently used for real-time nucleic acid analysis.

  7. Water Mediated Wittig Reactions of Aldehydes in the Teaching Laboratory: Using Sodium Bicarbonate for the in Situ Formation of Stabilized Ylides

    Kelly, Michael J. B.; Fallot, Lucas B.; Gustafson, Jeffrey L.; Bergdahl, B. Mikael


    The synthesis of alkenes using the Wittig reaction is a traditional part of many undergraduate organic chemistry teaching laboratory curricula. The aqueous medium version of the Wittig reaction presented is a reliable adaptation of this alkene formation reaction as a very safe alternative in the introductory organic chemistry laboratory. The…

  8. Metabolism-dependent mutagenicity of a compound containing a piperazinyl indazole motif: Role of a novel p450-mediated metabolic reaction involving a putative oxaziridine intermediate.

    Chen, Hao; Murray, Joel; Kornberg, Brian; Dethloff, Lloyd; Rock, David; Nikam, Sham; Mutlib, Abdul E


    Compound 1a (6-chloro-5-{3-[4-(1H-indazol-3-yl)-piperazin-1-yl]-propyl}-3,3-dimethyl-1,3-dihydro-indol-2-one) was mutagenic to Salmonella typhimurium TA98 in the presence of rat liver S9 subcellular fraction. The metabolism of 1a in rat liver S9 or microsomes demonstrated that it underwent a P450-mediated N-deindazolation (loss of indazole ring) as a predominant metabolic pathway. To investigate a possible link between metabolism and mutagenicity, a structural analogue 1b (6-chloro-5-{3-[4-(1H-indazol-3-yl)-piperidin-1-yl]-propyl}-3,3-dimethyl-1,3-dihydro-indol-2-one), the cleaved product 2a (6-chloro-3,3-dimethyl-5-(3-piperazin-1-yl-propyl)-1,3-dihydro-indol-2-one), and the core motif 3a (3-piperazinyl indazole) were evaluated in the Ames assay. It was found that 1b was not mutagenic to Salmonella typhimurium TA98 in the absence or presence of a metabolic activating system. In contrast to 1a, 1b did not undergo the metabolic cleavage (loss of indazole ring). Marginal mutagenicity of 2a to TA98 was observed with rat liver S9, whereas 3a was shown to be a promutagen. It was further demonstrated that 1a inactivated P450 3A, the principle enzyme catalyzing the N-deindazolation reaction, in an NADPH-, time-, and concentration-dependent manner. The kinetics of inactivation was characterized by a K(I) of 8.1 microM and k(inact) of 0.114 min(-1). The differences in mutagenicity between 1a and 1b suggest that a chemical bond extending from the 3-position of the indazole to a heteroatom (as part of another cyclic ring) is a prerequisite for the toxicity. The metabolic process leading to the elimination of the indazole from the rest of the molecule apparently plays a key role in causing mutagenicity. It is postulated that the N-deindazolation of 1a proceeds via an oxaziridine intermediate, the formation of which is indirectly inferred from the presence of benzoic acid in microsomal incubations. Benzoic acid is thought to be derived from the hydrolysis of 3-indazolone, an

  9. Stereoselective Synthesis of trans-Olefins by the Copper-Mediated SN2′ Reaction of Vinyl Oxazines with Grignard Reagents. Asymmetric Synthesis of D-threo-Sphingosines

    Singh, Om V; Han, Hyunsoo


    The SN2′ reaction of 6-vinyl-5,6-dihydro-4H-[1,3]oxazines with Grignard reagents in the presence of CuCN was studied, and high trans selectivity for the formation of double bond was observed with a variety of RMgX. The SN2′ reaction, coupled with regioselective asymmetric aminohydroxylation reaction, provided a highly efficient route for the asymmetric synthesis of D-threo-N-acetylsphingosine.

  10. The effect of low-level laser irradiation on sperm motility, and integrity of the plasma membrane and acrosome in cryopreserved bovine sperm.

    Guilherme Henrique C Fernandes

    Full Text Available Freezing changes sperm integrity remarkably. Cryopreservation involves cooling, freezing, and thawing and all these contribute to structural damage in sperm, resulting in reduced fertility potential. Low-level laser irradiation (LLLI could increase energy supply to the cell and cause reactive oxygen species reduction (ROS, contributing to the restoration of oxygen consumption and adenosine triphosphate synthesis (ATP in the mitochondria. Our goal was to analyze the effects of low-level laser irradiation on sperm motility and integrity of the plasma membrane and acrosome in cryopreserved bovine sperm.We analyzed 09 samples of bull semen (Bos taurus indicus, divided into three groups: a control group without laser irradiation, a 4J group subjected to a laser irradiation dose of 4 joules, and a 6J group subjected to dose of 6 joules. Samples were divided for the analysis of cell viability and acrosomal membrane integrity using flow cytometry; another portion was used for motion analysis. Irradiation was performed in petri dishes of 30 mm containing 3 ml of semen by an aluminum gallium indium phosphide laser diode with a wavelength of 660 nm, 30 mW power, and energy of 4 and 6 joules for 80 and 120 seconds respectively. Subsequently, the irradiated and control semen samples were subjected to cryopreservation and analyzed by flow cytometry (7AAD and FITC-PSA using the ISAS--Integrated Semen Analysis System.Flow cytometry showed an increase in the percentage of live sperm cells and acrosome integrity in relation to control cells when subjected to irradiation of low-power laser in two different doses of 4 and 6 joules (p < 0.05. In the analysis of straightness, percentage of cell movement, and motility, a dose of 4 joules was more effective (p < 0.05.We conclude that LLLI may exert beneficial effects in the preservation of live sperm. A dose of 4 joules prior to cryopreservation was more effective than a dose of 6 joules in preserving sperm motility.

  11. Glycolipid migration from the apical to the equatorial subdomains of the sperm head plasma membrane precedes the acrosome reaction: evidence for a primary capacitation event in boar spermatozoa

    Gadella, B.M.; Lopes-Cardozo, M.; Colenbrander, B.; van Goldie, L.M.G.; Gadella, Th.W.J.


    In order to extend the static information of immunolabelling sulphogalactolipids in fixed boar spermatozoa, a fluorescent sulphogalactolipid analogue, galactose(3-sulphate)-b1-1¢[( N-lissamine rhodaminyl)-12-aminododecanoyl]-sphingosine, was incorporated into plasma membranes of living spermatozoa a

  12. Effect of heparin, caffeine and calcium ionophore A23187 on in vitro induction of the acrosome reaction of fresh ram spermatozoa

    K.H. El-Shahat


    Conclusion: The best concentration of heparin, caffeine and ionophore A23187 are 75 μg/mL, 1 mg/mL, 1.55 mM/mL for 3, 1, 4 h incubation respectively and can be used for in vitro fertilization in sheep.

  13. 甲氧滴滴涕对大鼠精子顶体反应的影响%Effect of methoxychlor on rat sperm acrosome reaction

    刘伏祥; 黄平; 文建国; 杨静; 王坤龙


    目的:探讨甲氧滴滴涕(methoxychlor, MXC)对雄性大鼠精子顶体反应的影响.方法:在体外培养的精子悬液中加入不同浓度的MXC和孕酮处理,通过精子考马斯亮蓝染色,镜检计数顶体反应型精子的百分率.结果:与空白组比较,单纯经MXC处理组的顶体反应型精子百分率明显增加,另加孕酮的各处理组顶体反应型精子的百分率增加尤为明显,MXC终浓度≤6.25μg/ml的处理组顶体反应型精子百分率不增加.结论:MXC可促进大鼠精子发生顶体反应且与其剂量有关,当MXC终浓度≤6.25μg/ml不诱发顶体反应.MXC能加强孕酮诱发精子顶体反应的作用.

  14. [Values of the sperm deformity index, acrosome abnormity rate, and sperm DNA fragmentation index of optimized sperm in predicting IVF fertilization failure].

    Jiang, Wei-jie; Jin, Fan; Zhou, Li-ming


    To investigate the values of the sperm deformity index (SDI), acrosome abnormity rate (AAR), and DNA fragmentation index (DFI) of optimized sperm in the prediction of fertilization failure (fertilization rate fertilization (IVF). We selected 695 cycles of conventional IVF for pure oviductal infertility in this study, including 603 cycles of normal fertilization and 92 cycles of fertilization failure. On the day of oocyte retrieval, we examined sperm morphology, acrosome morphology, and DNA fragmentation using the Diff-Quik, PSA-FITC and SCD methods. We established the joint predictor (JP) by logistic equation and analyzed the values of different parameters in predicting fertilization failure with the receiver operating characteristic (ROC) curve. The fertilization rate was negatively correlated with SDI (r = - 0.07; P = 0.03), AAR (r = -0.49; P fertilization group were 1.24 ± 0.20, (7.75 ± 2.28)%, and (7.87 ± 3.15)%, and those in the fertilization failure group were 1.42 ± 0.15, (12.02 ± 3.06)%, and (13.32 ± 4.13)%, respectively, all with statistically significant differences between the two groups (P fertilization failure ( OR = 2.68, 14.11, and 3.85; P = 0.01, fertilization failure were approximately 1.45, 10%, and 12%. The SDI, AAR and DFI of optimized sperm are closely associated with the fertilization rate, and all have the value for predicting fertilization failure in IVF. The AAR is more valuable than the other single predictors, but JP is more effective than the AAR.

  15. Lanthanide-mediated organic synthesis : lanthanide(III) compounds as Lewis acid catalysts and cerium(IV) compounds as reagents for reactions in ionic liquids

    Deleersnyder, Karen


    In this PhD project, new procedures were investigated for various important organic reactions. Nowadays, organic procedures should not only result in high reaction yields and purity but moreover they should be designed to be environmentally friendly as well. Therefore, a proper choice of catalyst and solvent is an important aspect. In this study, greener solvents such as ionic liquids, water and rather unhazardous organic solvents were used. Moreover, this PhD research was focused on the ...

  16. Tetra- and mono-organotin reagents in palladium-mediated cross-coupling reactions for the labeling with carbon-11 of PET tracers

    Bourdier, T.; Huiban, M.; Sobrio, F.; Perrio, C.; Barre, E. [Groupe de Dev Methodol en Tomographie par Emission de Positons, UMR CEA 2E, Universite deCaen, Centre Cyceron, F-14070 Caen Cedex (France); Fouquet, A.; Huet, A. [Laboratoire de Chimie Organique et Organometallique, UMR CNRS 3802, Univ Bordeaux I, F-33405 Talence Cedex (France)


    The palladium-catalyzed cross-coupling reactions between a (trimethylstannyl)arene and [{sup 11}C]methyl iodide (Stille reaction) or between an aryl halide and a [{sup 11}C]monomethyltin reagent issued from Lappert's stannylene, were developed for the synthesis of polyfunctional [{sup 11}C]methyl quinolines and quinoline-imides as potential tracers for positron emission tomography (PET). (authors)

  17. A Template-Mediated Click-Click Reaction: PNA-DNA, PNA-PNA (or Peptide) Ligation, and Single Nucleotide Discrimination

    Peng, Xiaohua; Li, Hong; Seidman, Michael


    A highly efficient chemical ligation was developed for quantitative conjugation of PNA with DNA (PNA or peptide) using the copper-catalyzed azide-alkyne cycloaddition reaction. While PNAs with an alkyne at the C-terminus and an azide at the N-terminus have been used, an efficient click-click reaction occurs. The PNA click ligation is sequence-specific and capable of single nucleotide discrimination.

  18. Synthesis of 3,3-disubstituted oxindoles by visible-light-mediated radical reactions of aryl diazonium salts with N-arylacrylamides.

    Fu, Weijun; Xu, Fengjuan; Fu, Yuqin; Zhu, Mei; Yu, Jiaqi; Xu, Chen; Zou, Dapeng


    A mild and efficient visible-light-mediated diarylation of N-arylacrylamides with aryl diazonium salts under mild conditions has been developed. This method provides convenient access to a variety of useful 3,3-disubstituted oxindoles by constructing two C-C bonds in one step.

  19. Highly enantio- and diastereoselective one-pot reactions in aqueous media : Combined asymmetric Rh-catalyzed conjugate addition/metal-mediated allylation

    Kallstrom, Sara; Jagt, Richard B. C.; Sillanpaa, Reijo; Feringa, Ben L.; Minnaard, Adriaan J.; Leino, Reko; Källström, Sara; Sillanpää, Reijo


    1,3-Disubstituted, enantiopure cyclohexanols have been prepared in very high diastereoselectivities and good yields by a concise one-pot method combining the enantioselective rhodium-catalyzed conjugate addition of arylboronic acids with indium-mediated allylation into a highly efficient one-pot rea

  20. Swi5-Sfr1 protein stimulates Rad51-mediated DNA strand exchange reaction through organization of DNA bases in the presynaptic filament.

    Fornander, Louise H


    The Swi5-Sfr1 heterodimer protein stimulates the Rad51-promoted DNA strand exchange reaction, a crucial step in homologous recombination. To clarify how this accessory protein acts on the strand exchange reaction, we have analyzed how the structure of the primary reaction intermediate, the Rad51/single-stranded DNA (ssDNA) complex filament formed in the presence of ATP, is affected by Swi5-Sfr1. Using flow linear dichroism spectroscopy, we observe that the nucleobases of the ssDNA are more perpendicularly aligned to the filament axis in the presence of Swi5-Sfr1, whereas the bases are more randomly oriented in the absence of Swi5-Sfr1. When using a modified version of the natural protein where the N-terminal part of Sfr1 is deleted, which has no affinity for DNA but maintained ability to stimulate the strand exchange reaction, we still observe the improved perpendicular DNA base orientation. This indicates that Swi5-Sfr1 exerts its activating effect through interaction with the Rad51 filament mainly and not with the DNA. We propose that the role of a coplanar alignment of nucleobases induced by Swi5-Sfr1 in the presynaptic Rad51/ssDNA complex is to facilitate the critical matching with an invading double-stranded DNA, hence stimulating the strand exchange reaction.

  1. Role of mobile passenger lymphocytes in the rejection of renal and cardiac allografts in the rat. A passenger lymphocyte-mediated graft-versus-host reaction amplifies the host response

    van Vrieshilfgaarde, R.; Hermans, P.; Terpstra, J.L.; van Breda Viresman, P.J.


    It is demonstrated that passenger lymphocytes migrate out of rat renal allografts into host spleens in a radioresistant fashion. These mobile passenger lymphocytes within BN kidney and heart transplants are immunocompetent, since they elicit a graft-versus-host (GVH) reaction in the spleens of (LEW x BN)F2 hybrid hosts. The greater GVH reaction in (LEW x BN)F1 recipients of BN kidneys reflects the greater number of mobile passenger lymphocytes in the kidney when compared to the heart. The mobile passenger lymphocytes within BN renal allografts also cause a proliferative response in the spleens of the LEW hosts as well as an accelerated rejection of BN renal allografts when compared to BN cardiac allografts, for the differences between BN kidney and heart, both in terms of splenomegaly elicited in LEW as well as tempo of rejection, are abolished by total body x-irradiation of the donor with 900 rad. Results indicate that a mobile passenger lymphocyte mediated GVH reaction in the central lymphoid organs of the host augments the host response to allogenic kidneys and contributes materially to first-set renal allograft rejection; this GVH reaction on the other hand is not conspicuously present in LEW recipients of BN cardiac allografts and has therefore little effect on first-set cardiac allograft rejection.

  2. Evidence for a Precursor Complex in C-H Hydrogen Atom Transfer Reactions Mediated by a Manganese(IV) Oxo Complex

    Garcia Bosch, Isaac; Company Casadevall, Anna; Cady, Clyde W.; Styring, Stenbjörn; Browne, Wesley R; Ribas Salamaña, Xavi; Costas Salgueiro, Miquel


    HAT trick: [MnIV(OH)2(H,MePytacn)]2+ (A) and [MnIV(O)(OH)(H,MePytacn)]+ (B) differ in their reactions with CH bonds: compound A engages in typical single-step hydrogen atom transfer (HAT) reactions, whereas B first forms a substrate–B encounter complex (C; see scheme). This equilibrium alters the relative CH reactivity from that expected from CH bond dissociation energies Aquest mateix article està publicat a l'edició alemanya d''Angewandte Chemie' (ISSN 0044-8249, EISSN 1521-3757), 2011, ...

  3. Inhibitory effects of whisky congeners on IgE-mediated degranulation in rat basophilic leukemia RBL-2H3 cells and passive cutaneous anaphylaxis reaction in mice.

    Itoh, Tomohiro; Tsukane, Mariko; Koike, Minako; Nakamura, Chizu; Ohguchi, Kenji; Ito, Masafumi; Akao, Yukihiro; Koshimizu, Seiichi; Nozawa, Yoshinori; Wakimoto, Toshiyuki; Nukaya, Haruo; Suwa, Yoshihide


    Whisky is matured in oak casks. Many nonvolatile substances (whisky congeners, WC) seep from the oak cask during the maturing process. In this study, three antiallergic agents (syringaldehyde, SA; lyoniresinol, Lyo; and ellagic acid, EA) were isolated from WC. Treatment with SA, Lyo, and EA reduced the elevation of intracellular free Ca(2+) concentration ([Ca(2+)]i) and intracellular ROS production caused by FcepsilonRI activation. The inhibitions of the elevation of [Ca(2+)]i and intracellular ROS production by SA and Lyo were mainly due to the suppression of the NADPH oxidase activity and scavenging of the produced radical, respectively. On the other hand, EA inactivated spleen tyrosine kinase and led to the inhibition of the elevation of [Ca(2+)]i and intracellular ROS production. Furthermore, it was found that WC strongly inhibited IgE binding to the FcepsilonRIalpha chain, whereas SA, Lyo, and EA did not indicate this inhibitory effect. These results suggest that WC inhibits allergic reactions through multiple mechanisms. To disclose the in vivo effects of WC, SA, Lyo, and EA, these compounds were administered to type I allergic model mice, and the passive cutaneous anaphylaxis (PCA) reaction was measured. These compounds remarkably suppressed the PCA reaction. Taken together, these findings suggest that WC seemed to be beneficial to ameliorate allergic reactions.

  4. LDA-mediated selective addition reaction of vinylidenecyclopropanes with aldehydes, ketones, and enones: facile synthesis of vinylcyclopropenes, allenols, and 1,3-enynes.

    Lu, Jian-Mei; Shi, Min


    Highly selective addition reaction of vinylidenecyclopropanes 1 was realized by treatment with LDA in THF and quenching with aldehydes, ketones, and enones. A number of vinylcyclopropenes, allenols, and 1,3-enynes were obtained selectively in moderate to good yields depending on the nature of different electrophiles.

  5. Kinetics and thermodynamics of oxidation mediated reaction in L-cysteine and its methyl and ethyl esters in dimethyl sulfoxide-d6 by NMR spectroscopy

    Dougherty, Ryan J.; Singh, Jaideep; Krishnan, V. V.


    L-Cysteine (L-Cys), L-Cysteine methyl ester (L-CysME) or L-Cysteine ethyl ester (L-CysEE), when dissolved in dimethyl sulfoxide, undergoes an oxidation process. This process is slow enough and leads to nuclear magnetic resonance (NMR) spectral changes that could be monitored in real time. The oxidation mediated transition is modeled as a pseudo-first order kinetics and the thermodynamic parameters are estimated using the Eyring's formulation. L-Cysteine and their esters are often used as biological models due to the remarkable thiol group that can be found in different oxidation states. This oxidation mediated transition is due to the combination of thiol oxidation to a disulfide followed by solvent-induced effects may be relevant in designing cysteine-based molecular models.

  6. Frequent occurrence of T cell–mediated late reactions revealed by atopy patch testing with hypoallergenic rBet v 1 fragments

    Campana, Raffaela; Moritz, Katharina; Marth, Katharina; Neubauer, Angela; Huber, Hans; Henning, Rainer; Blatt, Katharina; Hoermann, Gregor; Brodie, Tess M.; Kaider, Alexandra; Valent, Peter; Sallusto, Federica; Wöhrl, Stefan; Valenta, Rudolf


    Background Late allergic reactions are common in the course of allergen-specific immunotherapy and even occur with allergy vaccines with reduced IgE reactivity. Objective We sought to study atopy patch test (APT) reactions and T-cell responses to the recombinant birch pollen allergen Bet v 1 and recombinant hypoallergenic T-cell epitope–containing Bet v 1 fragments in patients with birch pollen allergy with and without atopic dermatitis (AD). Methods A clinical study was conducted in 15 patients with birch pollen allergy with AD (group 1), 5 patients with birch pollen allergy without AD (group 2), 5 allergic patients without birch pollen allergy (group 3), and 5 nonallergic subjects (group 4) by performing skin prick tests and APTs with rBet v 1 and hypoallergenic rBet v 1 fragments. T-cell, cutaneous lymphocyte antigen (CLA)+ and CCR4+ T-cell and cytokine responses were studied by thymidine uptake, carboxyfluorescein diacetate succinimidyl ester staining, and Luminex technology, respectively. Results rBet v 1 and hypoallergenic rBet v 1 fragments induced APT reactions in not only most of the patients with birch pollen allergy with AD (11/15) but also in most of those without AD (4/5). Patients with birch pollen allergy with AD had higher Bet v 1–specific proliferation of CLA+ and CCR4+ T cells compared with patients with birch pollen allergy without AD. There were no differences in Bet v 1–specific CLA+ and CCR4+ proliferation and cytokine secretion in patients with and without APT reactions. Conclusion Hypoallergenic rBet v 1 fragments induce T cell–dependent late reactions not only in patients with birch pollen allergy with AD but also in those without AD, which can be determined based on APT results but not based on in vitro parameters. PMID:26518092

  7. 糖化学中锡介入的选择性反应%Tin-mediated selective reaction in carbohydrate chemistry

    楼鑫; Seamas Cassidy


    The structure of complex of dibutylstannylene acetal with sugar revealed the reasons for selective reaction. And the application of method in the various types of chemical reactions such as acylation,alkylation,oxidation,sulfonation and the performance of the selectivity were discussed in detail.%本文从糖锡络合物结构出发,揭示了锡介入方法进行选择性反应的原因.并对该方法在糖化学各类不同类型的反应如酰化,烃化,氧化,磺化所表现的选择性进行了详细的论述.

  8. An efficient and rapid synthesis of 3-hydroxy-3-alkyl-2-oxindoles via Zn-mediated barbier-type reaction under aqueous conditions



    A robust and rapid synthesis of 3-hydroxy-3-alkyl-2-oxindoles from isatins is described. This method introduces an ecofriendly, un-activated Zn dust, solid NH₄Cl and substrates under aqueous conditions, which has produced the product in moderate to good yields. Without using column chromatography, majority of the compounds were isolated in analytically pure form. The progress of the reaction could be visualized by naked eye.

  9. Time-resolved spectroscopic characterization of a novel photodecarboxylation reaction mediated by homolysis of a carbon α-bond in flurbiprofen.

    Su, Tao; Ma, Jiani; Wong, Naikei; Phillips, David Lee


    Flurbiprofen (Fp), a nonsteroidal anti-inflammatory drug (NSAID) currently in use for arthritis pain relief and in clinical trials for metastatic prostate cancer, can induce photosensitization and phototoxicity upon exposure to sunlight. The mechanisms responsible for Fp phototoxicity are poorly understood and deserve investigation. In this study, the photodecarboxylation reaction of Fp, which has been assumed to underpin its photoinduced side effects, was explored by femtosecond transient absorption (fs-TA), nanosecond transient absorption (ns-TA), and nanosecond time-resolved resonance Raman (ns-TR(3)) spectroscopic techniques in pure acetonitrile (MeCN) solvent. Density functional theory (DFT) calculations were also performed to facilitate the assignments of transient species. The resonance Raman and DFT calculation results reveal that the neutral form of Fp was the predominant species present in MeCN. Analysis of the ultraviolet/visible absorption spectrum and results from TD-DFT calculations indicate that the second excited singlet (S2) can be excited by 266 nm light. Due to its intrinsic instability, S2 rapidly underwent internal conversion (IC) to decay to the lowest lying excited singlet (S1), which was observed in the fs-TA spectra at very early delay times. Intriguingly, three distinct pathways for S1 decay seem to coexist. Specifically, other than fluorescence emission back to the ground state and transformation to the lowest triplet state T1 through intersystem crossing (ISC), the homolysis of the carbon α-bond decarboxylation reaction proceeded simultaneously to give rise to two radical species, one being carboxyl and another being the residual, denoted as FpR. The coexistence of the triplet Fp (T1) and FpR species was verified by means of TR(3) spectra along with ns-TA spectra. As a consequence of its apparent high reactivity, the FpR intermediate was observed to undergo oxidation under oxygen-saturated conditions to yield another radical species

  10. Intracytoplasmic Sperm Injection Fertilization Rate Does Not-Depend on the Proportion of Round-headed Sperm, Small acrosomal Sperm, or Morphologically Normal Sperm in Patients with Partial Globozoospermia

    Ling-Ying Jiang; Ling-Yun Yang; Xiao-Mei Tong; Hai-Yan Zhu; Ya-Mei Xue; Wen-Zhi Xu; Yang Yang


    Background:Generally,intracytoplasmic sperm injection (ICSI) may be the preferable method to treat partial globozoospermia,but whether there exist some correlations between ICSI fertilization rate and the proportion of round-headed sperm or morphologically normal sperm remains open.This study was to explore the correlation between ICSI fertilization rate and the sperm morphology in patients with partial globozoospermia.Methods:Thirty-four patients diagnosed with partial globozoospermia accepted the following assisted fertilization treatments-2 cases accepted in-vitro fertilization (IvF) alone,26 cases accepted ICSI alone,and 6 accepted split IVF/ICSI.Detailed morphological characteristics were described using Diff-Quik rapid staining.Sixty cases accepting IVF or ICSI treatment in our reproductive center were considered as the control group after being matched by relevant criteria.Fertilization rate,embryo quality,embryo implantation rate and clinical pregnancy rate were calculated.Results:Besides very high proportion of round-headed sperm,partial globozoospermia also showed very high proportion of small-acrosomal sperm and very low proportion of morphologically normal sperm.Fertilization rate of IVF (IVF alone plus split IVF) was very low in partial globozoospermia (25.4% ± 17.4%),but ICSI (ICSI alone plus split ICSI) achieved satisfying fertilization rate compared with the control group (66.2% ± 22.5% vs.68.8% ± 29.4%,P > 0.05).In patients with partial globozoospermia,there were no correlations between ICSI fertilization rate and the proportion of round-headed sperm,small-acrosomal sperm,or morphologically normal sperm.Conclusions:There was high proportion of small-acrosomal sperm in partial globozoospermia.For patients with partial globozoospermia,ICSI is more preferable than IVF.ICSI fertilization rate does not depend on the proportion of round-headed sperm,small-acrosomal sperm,or morphologically normal sperm.

  11. Synthesis of robust hierarchical silica monoliths by surface-mediated solution/precipitation reactions over different scales: designing capillary microreactors for environmental applications.

    García-Aguilar, J; Miguel-García, I; Berenguer-Murcia, Á; Cazorla-Amorós, D


    A synthetic procedure to prepare novel materials (surface-mediated fillings) based on robust hierarchical monoliths is reported. The methodology includes the deposition of a (micro- or mesoporous) silica thin film on the support followed by growth of a porous monolithic SiO2 structure. It has been demonstrated that this synthesis is viable for supports of different chemical nature with different inner diameters without shrinkage of the silica filling. The formation mechanism of the surface-mediated fillings is based on a solution/precipitation process and the anchoring of the silica filling to the deposited thin film. The interaction between the two SiO2 structures (monolith and thin film) depends on the porosity of the thin film and yields composite materials with different mechanical stability. By this procedure, capillary microreactors have been prepared and have been proved to be highly active and selective in the total and preferential oxidation of carbon monoxide (TOxCO and PrOxCO).

  12. Intracellular calcium movements of boar spermatozoa during 'in vitro' capacitation and subsequent acrosome exocytosis follow a multiple-storage place, extracellular calcium-dependent model.

    Yeste, M; Fernández-Novell, J M; Ramió-Lluch, L; Estrada, E; Rocha, L G; Cebrián-Pérez, J A; Muiño-Blanco, T; Concha, I I; Ramírez, A; Rodríguez-Gil, J E


    This work analysed intracellular calcium stores of boar spermatozoa subjected to 'in vitro' capacitation (IVC) and subsequent progesterone-induced acrosome exocytosis (IVAE). Intracellular calcium was analysed through two calcium markers with different physico-chemical properties, Fluo-3 and Rhod-5N. Indicative parameters of IVC and IVAE were also evaluated. Fluo-3 was located at both the midpiece and the whole head. Rhod-5N was present at the sperm head. This distribution did not change in any of the assayed conditions. Induction of IVC was concomitant with an increase in both head and midpiece Ca(2+) signals. Additionally, while IVC induction was concurrent with a significant (p Fluo-3 marking at the midpiece increased after progesterone addition to sperm cells incubated in a medium without Ca(2+) . The simultaneous addition of progesterone with the calcium chelant EGTA inhibited IVAE, and this was accompanied by a significant (p < 0.05) decrease in the intensity of progesterone Ca(2+) -induced peak, O2 consumption and ATP levels. Our results suggest that boar spermatozoa present different calcium deposits with a dynamic equilibrium among them and with the extracellular environment. Additionally, the modulation role of the intracellular calcium in spermatozoa function seems to rely on its precise localization in boar spermatozoa. © 2015 American Society of Andrology and European Academy of Andrology.

  13. Adrenergic System Activation Mediates Changes in Cardiovascular and Psychomotoric Reactions in Young Individuals after Red Bull© Energy Drink Consumption

    Ana Cavka


    Full Text Available Objectives. To assess the effect of Red Bull© on (1 blood glucose and catecholamine levels, (2 cardiovascular and respiratory function changes before, during, and after exercise, (3 reaction time, (4 cognitive functions, and (5 response to mental stress test and emotions in young healthy individuals (N=38. Methods. Heart rate (HR and arterial blood pressure (ABP, blood glucose, adrenaline, and noradrenalin plasma levels were measured before and after Red Bull© intake. Participants were subjected to 4 different study protocols by randomized order, before and 30 minutes after consumption of 500 mL of Red Bull©. Results. Mean ABP and HR were significantly increased at rest after Red Bull© intake. Blood glucose level and plasma catecholamine levels significantly increased after Red Bull© consumption. Heart rate, respiration rate, and respiratory flow rate were significantly increased during exercise after Red Bull© consumption compared to control condition. Intake of Red Bull© significantly improved reaction time, performance in immediate memory test, verbal fluency, and subject’s attention as well as performance in mental stress test. Conclusion. This study demonstrated that Red Bull© has beneficial effect on some cognitive functions and effect on cardiovascular and respiratory system at rest and during exercise by increasing activity of the sympathetic nervous system.

  14. The effects of phorbol ester activation and reactive oxygen species scavengers on the macrophage-mediated foreign body reaction to polyurethanes.

    McBane, Joanne E; Matheson, Loren A; Santerre, J Paul; Labow, Rosalind S


    Phorbol myristate acetate, a protein kinase C activator, inhibited monocyte-derived macrophage (MDM)-mediated degradation of aliphatic (HDI) polycarbonate-based polyurethanes but not degradation of the aromatic polycarbonate-based polyurethane (MDI). The objectives of this study were to determine if reactive oxygen species are involved in the phorbol myristate acetate effect on esterase activity and MDM-mediated polycarbonate-based polyurethane degradation and to find a good marker of material-initiated activation of MDM. The phorbol myristate acetate-dependent effects of the material chemistry on cell activation and degradation were evaluated by adding reactive oxygen species scavengers, catalase plus superoxide dismutase to MDM and assaying possible markers of MDM activation: esterase activity, acid phosphatase activity, and high molecular weight group box 1 protein (HMGB1). All treatments reduced the esterase activity in MDM on HDI but not in MDM on MDI. Acid phosphatase was inhibited in MDM to varying degrees on all surfaces by phorbol myristate acetate or catalase plus superoxide dismutase either alone or together. Secretion of HMGB1 from MDM on HDI431 was higher than MDI; however only secretion from MDM on HDI was inhibited by phorbol myristate acetate. In MDM on HDI, catalase plus superoxide dismutase reduced intracellular HMGB1 levels +/- phorbol myristate acetate; whereas, catalase, superoxide dismutase plus phorbol myristate acetate increased intracellular HMGB1 in MDM on MDI, suggesting that esterase and HMGB1 are more specific markers of activation than acid phosphatase. Manipulation of signaling pathways may provide insight surrounding the mechanism of activation for oxidative and/or hydrolytic degradative pathways in the MDM response to material surface chemistry.

  15. From dihydrated iron(III) phosphate to monohydrated ammonium-iron(II) phosphate: Solvothermal reaction mediated by acetone-urea mixtures

    Alfonso, Belen F., E-mail: [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n 33007 Oviedo (Spain); Trobajo, Camino [Departamento de Quimica Organica e Inorganica, Universidad de Oviedo-CINN, Julian Claveria 8, 33006 Oviedo (Spain); Pique, Carmen [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n 33007 Oviedo (Spain); Garcia, Jose R. [Departamento de Quimica Organica e Inorganica, Universidad de Oviedo-CINN, Julian Claveria 8, 33006 Oviedo (Spain); Blanco, Jesus A. [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n 33007 Oviedo (Spain)


    By reaction between synthetic phosphosiderite FePO{sub 4}{center_dot}2H{sub 2}O, urea (NH{sub 2}){sub 2}CO, and acetone (CH{sub 3}){sub 2}CO, we report a novel solvothermal synthesis of polycrystalline NH{sub 4}FePO{sub 4}{center_dot}H{sub 2}O. The preparation of other two individual phases, NH{sub 4}Fe{sub 2}(OH)(PO{sub 4}){sub 2}{center_dot}2H{sub 2}O and NH{sub 4}Fe{sub 2}(PO{sub 4}){sub 2}, is also described. The obtained product is a function of the reaction time and the N/P molar ratio in the reagent mixture, and the existence of structural memory in the dissolution-precipitation processes is discussed. Below 25 K, NH{sub 4}FePO{sub 4}{center_dot}H{sub 2}O behaves magnetically in a complex way, because both ferromagnetic and antiferromagnetic signals are superimposed, suggesting the existence of a canting of iron(II) magnetic moments. - Graphical abstract: Solvothermal synthesis of polycrystalline NH{sub 4}FePO{sub 4}{center_dot}H{sub 2}O is presented. The preparation of other two individual phases, NH{sub 4}Fe{sub 2}(OH)(PO{sub 4}){sub 2}{center_dot}2H{sub 2}O and NH{sub 4}Fe{sub 2}(PO{sub 4}){sub 2} as a function of the N/P molar ratio in the reagent mixture and the reaction time, is also described. Highlights: Black-Right-Pointing-Pointer Solvothermal synthesis of NH{sub 4}FePO{sub 4}{center_dot}H{sub 2}O from an Fe(III) phosphate: reduction process. Black-Right-Pointing-Pointer Formation of two intermediate metastable phases: phase diagram. Black-Right-Pointing-Pointer Thermal decomposition in two steps: mass loss of both water and ammonia. Black-Right-Pointing-Pointer Magnetic behaviour: AF+constant spontaneous magnetization.

  16. Doc2b promotes GLUT4 exocytosis by activating the SNARE-mediated fusion reaction in a calcium- and membrane bending-dependent manner.

    Yu, Haijia; Rathore, Shailendra S; Davis, Eric M; Ouyang, Yan; Shen, Jingshi


    The glucose transporter GLUT4 plays a central role in maintaining body glucose homeostasis. On insulin stimulation, GLUT4-containing vesicles fuse with the plasma membrane, relocating GLUT4 from intracellular reservoirs to the cell surface to uptake excess blood glucose. The GLUT4 vesicle fusion reaction requires soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) as the core fusion engine and a group of regulatory proteins. In particular, the soluble C2-domain factor Doc2b plays a key role in GLUT4 vesicle fusion, but its molecular mechanism has been unclear. Here we reconstituted the SNARE-dependent GLUT4 vesicle fusion in a defined proteoliposome fusion system. We observed that Doc2b binds to GLUT4 exocytic SNAREs and potently accelerates the fusion kinetics in the presence of Ca(2+). The stimulatory activity of Doc2b requires intact Ca(2+)-binding sites on both the C2A and C2B domains. Using electron microscopy, we observed that Doc2b strongly bends the membrane bilayer, and this membrane-bending activity is essential to the stimulatory function of Doc2b in fusion. These results demonstrate that Doc2b promotes GLUT4 exocytosis by accelerating the SNARE-dependent fusion reaction by a Ca(2+)- and membrane bending-dependent mechanism. Of importance, certain features of Doc2b function appear to be distinct from how synaptotagmin-1 promotes synaptic neurotransmitter release, suggesting that exocytic Ca(2+) sensors may possess divergent mechanisms in regulating vesicle fusion.

  17. Selective amplification of cDNA sequence from total RNA by cassette-ligation mediated polymerase chain reaction (PCR): application to sequencing 6.5 kb genome segment of hantavirus strain B-1.

    Isegawa, Y; Sheng, J; Sokawa, Y; Yamanishi, K; Nakagomi, O; Ueda, S


    A method, referred to as cassette-ligation mediated polymerase chain reaction (PCR), has been developed to permit selective and specific amplification of cDNA sequence from total cellular RNA. This technique comprises (i) digestion of cDNA with multiple restriction enzymes, (ii) ligation of cleavage products to double-stranded DNA cassettes possessing a corresponding restriction site and (iii) amplification of cassette-ligated restriction fragments containing a short, known sequence (but not all the other ligation products) by PCR using the specific and cassette primers; the specific primer is designed to prime synthesis from the known sequence of the cDNA whereas the cassette primer anneals to one strand of the cassette. Sequencing from the cassette primer provides information to design a new primer for the next walking step. The amplified cDNA fragments are often larger than the maximum DNA fragments (500-600 bp) that can be sequenced without the need of synthesizing internal sequencing primer. Each of such large cDNA fragments is dissected into smaller DNA fragments by repeating cassette-ligation mediated PCR exploiting different restriction sites and different sets of cassette primers. This dissection process reduces the number of specific primers to a minimum, thereby increasing the speed of sequencing and minimizing the overall cost. We have successfully applied this cDNA walking and sequencing by the cassette-ligation mediated PCR to the sequencing of an entire 6.5 kb genome segment of hantavirus strain B-1.(ABSTRACT TRUNCATED AT 250 WORDS)

  18. Utility of loop-mediated isothermal amplification assay, polymerase chain reaction, and elisa for diagnosis of leptospirosis in South Indian patients

    Mallika Sengupta


    Full Text Available Background: Leptospirosis is a zoonotic disease which requires laboratory diagnosis for confirmation. Materials and Methods: In this study serum samples from adults with acute undifferentiated fever (duration ≤15 days were tested for IgM antibodies to Leptospira by ELISA, PCR for rrs gene and loop-mediated isothermal amplification (LAMP assay for LipL32 and LipL41. Results: Among the 150 sera tested, three were positive by PCR, LAMP and IgM ELISA/modified Faines' criteria, two by only PCR; seven only by LAMP assay and forty fulfilled modified Faine's criteria (illness clinically compatible and IgM ELISA positive for leptospirosis. Clinical correlation revealed renal compromise, low platelet count and severe jaundice were significantly related to leptospirosis (P < 0.05. Conclusion: This study suggests that LAMP assay could be useful for diagnosis of leptospirosis during the 1st week of illness whereas IgM ELISA forms the mainstay of diagnosis from the 2nd week onward. Further studies especially community based, comparing ELISA, PCR, LAMP, culture and microscopic agglutination test are required to evaluate the veracity of these findings.

  19. Utility of Loop-mediated Isothermal Amplification Assay, Polymerase Chain Reaction, and ELISA for Diagnosis of Leptospirosis in South Indian Patients

    Sengupta, Mallika; Prabhakar, Abhilash Kundavaram Paul; Satyendra, Sowmya; Thambu, David; Abraham, Ooriapadickal Cherian; Balaji, Veeraraghavan; Chen, Hua-Wei; Chao, Chien-Chung; Ching, Wei-Mei; Prakash, John Antony Jude


    Background: Leptospirosis is a zoonotic disease which requires laboratory diagnosis for confirmation. Materials and Methods: In this study serum samples from adults with acute undifferentiated fever (duration ≤15 days) were tested for IgM antibodies to Leptospira by ELISA, PCR for rrs gene and loop-mediated isothermal amplification (LAMP) assay for LipL32 and LipL41. Results: Among the 150 sera tested, three were positive by PCR, LAMP and IgM ELISA/modified Faines’ criteria, two by only PCR; seven only by LAMP assay and forty fulfilled modified Faine's criteria (illness clinically compatible and IgM ELISA positive for leptospirosis). Clinical correlation revealed renal compromise, low platelet count and severe jaundice were significantly related to leptospirosis (P < 0.05). Conclusion: This study suggests that LAMP assay could be useful for diagnosis of leptospirosis during the 1st week of illness whereas IgM ELISA forms the mainstay of diagnosis from the 2nd week onward. Further studies especially community based, comparing ELISA, PCR, LAMP, culture and microscopic agglutination test are required to evaluate the veracity of these findings.

  20. The mechanism of the modified Ullmann reaction

    Sperotto, Elena; Klink, Gerard P.M. van; Koten, Gerard van; Vries, Johannes G. de


    The copper-mediated aromatic nucleophilic substitution reactions developed by Fritz Ullmann and Irma Goldberg required stoichiometric amounts of copper and very high reaction temperatures. Recently, it was found that addition of relatively cheap ligands (diamines, aminoalcohols, diketones, diols) ma

  1. Lewis acid mediated vinyl-transfer reaction of alkynes to N-alkylimines by using the N-alkyl residue as a sacrificial hydrogen donor.

    Malakar, Chandi C; Stas, Sara; Herrebout, Wouter; Abbaspour Tehrani, Kourosch


    A variety of N-alkyl-α,α-dichloroaldimines were vinylated by terminal acetylenes in the presence of Lewis acids such as In(OTf)3 or BF3 ⋅OEt2 and hexafluoroisopropanol (HFIP) as an additive. The reaction proceeds at ambient temperature and leads to geometrically pure allylic β,β-dichloroamines. This approach is complementary to previously reported transition-metal-catalyzed vinyl-transfer methods, which are not applicable to aliphatic imines and are restricted to imines that contain an electron-withdrawing nitrogen substituent. In the present approach, terminal alkynes were used as a source of the vinyl residue, and the N-alkyl moiety of the imine acts as a sacrificial hydrogen donor. The additional advantage of this methodology is the fact that no external toxic or hazardous reducing agents or molecular hydrogen has to be used. This new methodology nicely combines a C(sp(2) )C(sp) bond formation, hydride transfer, and an unusual cleavage of an unactivated CN bond, thereby giving rise to functionalized primary allylic amines. A detailed experimental study supported by DFT calculations of the mechanism has been done. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Microwave Mediated Organic Reaction: A Convenient Approach for Rapid and Efficient Synthesis of Biologically Active Substituted 1,3-Dihydro-2H-indol-2-one Derivatives

    Jnyanaranjan Panda


    Full Text Available A simple and efficient method has been developed for the synthesis of 1,3-dihydro-2H-indol-2-one derivatives using microwave irradiation technique. By taking advantage of the efficient source of energy of microwave, compound libraries for lead generation and optimization can be assembled in a fraction of time. In the present work, first the Schiff’s bases are synthesized by reaction of isatin with substituted anilines in the presence of acetic acid under microwave heating. Then the condensation of Schiff bases with different secondary amines in the presence of formaldehyde produces Mannich bases. The newly synthesized Mannich bases were characterized by means of spectral data and then evaluated for anthelmintic activity against Pheretima posthuma (Indian earthworm and compared with standard albendazole. The compounds were evaluated at the concentrations of 10, 20, and 50 mg/mL. The effect of the standard drug albendazole at 10 mg/mL was also evaluated. The results of the present study indicate that some of the test compounds significantly demonstrated paralysis and also caused death of worms in a dose-dependent manner.

  3. Isomeric [RuCl2(dmso)2(indazole)2] complexes: ruthenium(II)-mediated coupling reaction of acetonitrile with 1H-indazole.

    Reisner, Erwin; Arion, Vladimir B; Rufińska, Anna; Chiorescu, Ion; Schmid, Wolfgang F; Keppler, Bernhard K


    Reaction of the antitumor complex trans-[Ru(III)Cl4(Hind)2]- (Hind = indazole) with an excess of dimethyl sulfoxide (dmso) in acetone afforded the complex trans,trans,trans-[Ru(II)Cl2(dmso)2(Hind)2] (1). Two other isomeric compounds trans,cis,cis-[Ru(II)Cl2(dmso)2(Hind)2] (2) and cis,cis,cis-[Ru(II)Cl2(dmso)2(Hind)2] (3) have been obtained on refluxing cis-[Ru(II)Cl(2)(dmso)(4)] with 2 equiv. of indazole in ethanol and methanol, respectively. Isomers 1 and 2 react with acetonitrile yielding the complexes trans-[Ru(II)Cl2(dmso)(Hind){HN=C(Me)ind}].CH3CN (4.CH3CN) and trans,cis-[Ru(II)Cl2(dmso)2{HN=C(Me)ind}].H2O (5.H2O), respectively, containing a cyclic amidine ligand resulting from insertion of the acetonitrile C triple bond N group in the N1-H bond of the N2-coordinated indazole ligand in the nomenclature used for 1H-indazole. These are the first examples of the metal-assisted iminoacylation of indazole. The products isolated have been characterized by elemental analysis, IR spectroscopy, UV-vis spectroscopy, electrospray mass-spectrometry, thermogravimetry, differential scanning calorimetry, 1H NMR spectroscopy, and solid-state 13C CP MAS NMR spectroscopy. The isomeric structures of 1-3 and the presence of a chelating amidine ligand in 4 and 5 have been confirmed by X-ray crystallography. The electrochemical behavior of 1-5 and the formation of 5 have been studied by cyclic voltammetry.

  4. Sperm Lysozyme-Like Protein 1 (SLLP1), an intra-acrosomal oolemmal-binding sperm protein, reveals filamentous organization in protein crystal form.

    Zheng, H; Mandal, A; Shumilin, I A; Chordia, M D; Panneerdoss, S; Herr, J C; Minor, W


    Sperm lysozyme-like protein 1 (SLLP1) is one of the lysozyme-like proteins predominantly expressed in mammalian testes that lacks bacteriolytic activity, localizes in the sperm acrosome, and exhibits high affinity for an oolemmal receptor, SAS1B. The crystal structure of mouse SLLP1 (mSLLP1) was determined at 2.15 Å resolution. mSLLP1 monomer adopts a structural fold similar to that of chicken/mouse lysozymes retaining all four canonical disulfide bonds. mSLLP1 is distinct from c-lysozyme by substituting two essential catalytic residues (E35T/D52N), exhibiting different surface charge distribution, and by forming helical filaments approximately 75 Å in diameter with a 25 Å central pore comprised of six monomers per helix turn repeating every 33 Å. Cross-species alignment of all reported SLLP1 sequences revealed a set of invariant surface regions comprising a characteristic fingerprint uniquely identifying SLLP1 from other c-lysozyme family members. The fingerprint surface regions reside around the lips of the putative glycan-binding groove including three polar residues (Y33/E46/H113). A flexible salt bridge (E46-R61) was observed covering the glycan-binding groove. The conservation of these regions may be linked to their involvement in oolemmal protein binding. Interaction between SLLP1 monomer and its oolemmal receptor SAS1B was modeled using protein-protein docking algorithms, utilizing the SLLP1 fingerprint regions along with the SAS1B conserved surface regions. This computational model revealed complementarity between the conserved SLLP1/SAS1B interacting surfaces supporting the experimentally observed SLLP1/SAS1B interaction involved in fertilization. © 2015 American Society of Andrology and European Academy of Andrology.

  5. DNA and DNA computation based on to ehold-mediated strand-displacement reactions%DNA及基于DNA链替换反应的分子计算∗

    肖石燕; 梁好均


    DNA是生物遗传信息的载体,同时也是一种理想的生物相容材料。单链黏性末端(toehold)协助的链替换反应是DNA常温纳米技术的基础。利用DNA的碱基互补特性和碱基序列的可编程性,人们可以基于DNA链替换反应构建分子机器并对其运转进行精确调控,实现各种复杂分子计算。本文回顾了近年来DNA结构和力学性质方面的研究进展,探讨DNA链替换反应的微观理解,介绍DNA分子计算领域的最新成果,以及它在DNA恒温自组装等方面的应用。%Other than being a carrier of the code of life, DNA can also be used as a kind of ideal biomaterial with good biocom-patibility. Considering the critical role of DNA less than 150 base pairs (bp) in cellular processes such as regulated gene expression, quantifying the intrinsic bend ability of DNA on a sub-persistence length scale is essential to understanding its molecular functions and the DNA-protein interaction. From the classical point of view, double-stranded DNA is assumed to be stiff and can be treated by semi-flexible chain, but recent studies have yielded contradictory results. A lot of studies tried to prove that the worm-like chain model can be used to fully describe DNA chain. However, recent theoretical and experimental studies indicated that DNA exhibits high flexibility on a short length scale, which cannot be described by the worm-like chain model. Further studies are needed to address the extreme flexibility of DNA on a short length scale. On the basis of the predictability of the double helical structure and the Watson-Crick binding thermodynamics for DNA, a class of DNA reactions can be defined, called toehold-mediated strand-displacement re-action, in which one complementary single-stranded DNA sequence first binds to the dangling toehold domain of the substrate in a pre-hybridized double-stranded DNA, then triggers the strand-displacement reaction, and finally results in the

  6. Intercultural Mediation

    Dragos Marian Radulescu; Denisa Mitrut


    The Intercultural Mediator facilitates exchanges between people of different socio-cultural backgrounds and acts as a bridge between immigrants and national and local associations, health organizations, services and offices in order to foster integration of every single individual. As the use mediation increases, mediators are more likely to be involved in cross-cultural mediation, but only the best mediators have the opportunity to mediate cross border business disputes or international poli...

  7. Pathophysiology of hemolytic transfusion reactions.

    Davenport, Robertson D


    Hemolytic transfusion reactions (HTR) are systemic reactions provoked by immunologic red blood cell (RBC) incompatibility. Clinical and experimental observations of such reactions indicate that they proceed through phases of humoral immune reaction, activation of phagocytes, productions of cytokine mediators, and wide-ranging cellular responses. HTR have many features in common with the systemic inflammatory response syndrome (SIRS). Knowledge of the pathophysiologic mechanisms in HTR suggest that newer biological agents that target complement intermediates or proinflammatory cytokines may be effective agents in the treatment of severe HTRs.

  8. Reaction Graph



    The paper proposes reaction graphs as graphical representations of computational objects.A reaction graph is a directed graph with all its arrows and some of its nodes labeled.Computations are modled by graph rewriting of a simple nature.The basic rewriting rules embody the essence of both the communications among processes and cut-eliminations in proofs.Calculi of graphs are ideentified to give a formal and algebraic account of reaction graphs in the spirit of process algebra.With the help of the calculi,it is demonstrated that reaction graphs capture many interesting aspects of computations.

  9. Development of peptide nucleic acid mediated polymerase chain reaction clamping (PMPC)--direct sequencing method for detecting lamivudine-resistant hepatitis B virus (HBV) variants with high sensitivity and specificity.

    Ogata, Norio; Ichida, Takafumi; Aoyagi, Yutaka; Kitajima, Isao


    Reduced sensitivity of HBV to lamivudine, which causes a viral breakthrough during treatment, is attributed to mutations within the tyrosine-methionine-aspartate(YMDD) locus in the reverse transcriptase(rt) domain of HBV polymerase, mainly a methionine(rtM204) substitution. The sensitive detection of such mutations before or early in treatment could assist in optimizing antiviral treatment. For this purpose, we developed peptide nucleic acid(PNA) mediated polymerase chain reaction(PCR) clamping(PMPC) with a PNA probe targeting the YMDD locus. We first tested this method for its sensitivity and specificity in detecting a mutant on HBV DNA standards consisting of serial copy number ratios of a known lamivudine-resistant, mutant clone with rtM204I(ATT) to a wild-type clone with rtM204(ATG). The sensitivity was 0.1 to 0.01% in the coexistence of wild-type clones and the specificity was guaranteed by direct sequencing of the products. We next applied this method to HBV DNA specimens extracted from serum from 4 chronic hepatitis B patients treated with lamivudine. Two of these exhibited a break-through of the HBV mutant with rtM204I(ATT), while the other 2 did not. Before treatment, all 4 patients showed HBV with rtM204I encoded by ATA. During treatment, HBV with the rtM204I(ATT) emerged in the 2 breakthrough patients more than 3 months before the breakthrough, whereas this and other known lamivudine-resistant viruses did not appear in the 2 non-breakthrough patients. Thus, our PMPC-direct sequencing method is highly sensitive and reliable for the early identification of lamivudine-resistant HBV that causes a viral breakthrough.

  10. Heat Sensing Receptor TRPV1 Is a Mediator of Thermotaxis in Human Spermatozoa

    Menegazzo, Massimo; Magagna, Sabina; Di Nisio, Andrea; Šabović, Iva; Rocca, Maria Santa; Scattolini, Valentina; Filippi, Andrea; Foresta, Carlo


    The molecular bases of sperm thermotaxis, the temperature-oriented cell motility, are currently under investigation. Thermal perception relies on a subclass of the transient receptor potential [TRP] channels, whose member TRPV1 is acknowledged as the heat sensing receptor. Here we investigated the involvement of TRPV1 in human sperm thermotaxis. We obtained semen samples from 16 normozoospermic subjects attending an infertility survey programme, testis biopsies from 6 patients with testicular germ cell cancer and testis fine needle aspirates from 6 patients with obstructive azoospermia undergoing assisted reproductive technologies. Expression of TRPV1 mRNA was assessed by RT-PCR. Protein expression of TRPV1 was determined by western blot, flow cytometry and immunofluorescence. Sperm motility was assessed by Sperm Class Analyser. Acrosome reaction, apoptosis and intracellular-Ca2+ content were assessed by flow cytometry. We found that TRPV1 mRNA and protein were highly expressed in the testis, in both Sertoli cells and germ-line cells. Moreover, compared to no-gradient controls at 31°C or 37°C (Ctrl 31°C and Ctrl 37°C respectively), sperm migration towards a temperature gradient of 31–37°C (T gradient) in non-capacitated conditions selected a higher number of cells (14,9 ± 4,2×106 cells T gradient vs 5,1± 0,3×106 cells Ctrl 31°C and 5,71±0,74×106 cells Ctrl 37°C; P = 0,039). Capacitation amplified the migrating capability towards the T gradient. Sperms migrated towards the T gradient showed enriched levels of both TRPV1 protein and mRNA. In addition, sperm cells were able to migrate toward a gradient of capsaicin, a specific agonist of TRPV1, whilst capsazepine, a specific agonist of TRPV1, blocked this effect. Finally, capsazepine severely blunted migration towards T gradient without abolishing. These results suggest that TRPV1 may represent a facilitating mediator of sperm thermotaxis. PMID:27992447

  11. Drug hypersensitivity reactions involving skin.

    Hausmann, Oliver; Schnyder, Benno; Pichler, Werner J


    Immune reactions to drugs can cause a variety of diseases involving the skin, liver, kidney, lungs, and other organs. Beside immediate, IgE-mediated reactions of varying degrees (urticaria to anaphylactic shock), many drug hypersensitivity reactions appear delayed, namely hours to days after starting drug treatment, showing a variety of clinical manifestations from solely skin involvement to fulminant systemic diseases which may be fatal. Immunohistochemical and functional studies of drug-specific T cells in patients with delayed reactions confirmed a predominant role for T cells in the onset and maintenance of immune-mediated delayed drug hypersensitivity reactions (type IV reactions). In these reactions, drug-specific CD4+ and CD8+ T cells are stimulated by drugs through their T cell receptors (TCR). Drugs can stimulate T cells in two ways: they can act as haptens and bind covalently to larger protein structures (hapten-carrier model), inducing a specific immune response. In addition, they may accidentally bind in a labile, noncovalent way to a particular TCR of the whole TCR repertoire and possibly also major histocompatibility complex (MHC)-molecules - similar to their pharmacologic action. This seems to be sufficient to reactivate certain, probably in vivo preactivated T cells, if an additional interaction of the drug-stimulated TCR with MHC molecules occurs. The mechanism was named pharmacological interaction of a drug with (immune) receptor and thus termed the p-i concept. This new concept may explain the frequent skin symptoms in drug hypersensitivity to oral or parenteral drugs. Furthermore, the various clinical manifestations of T cell-mediated drug hypersensitivity may be explained by distinct T cell functions leading to different clinical phenotypes. These data allowed a subclassification of the delayed hypersensitivity reactions (type IV) into T cell reactions which, by releasing certain cytokines and chemokines, preferentially activate and recruit

  12. Metal-catalyzed asymmetric aldol reactions

    Dias, Luiz C.; Lucca Junior, Emilio C. de; Ferreira, Marco A. B.; Polo, Ellen C., E-mail: [Universidade de Campinas (UNICAMP), SP (Brazil). Inst. de Quimica


    The aldol reaction is one of the most powerful and versatile methods for the construction of C-C bonds. Traditionally, this reaction was developed in a stoichiometric version; however, great efforts in the development of chiral catalysts for aldol reactions were performed in recent years. Thus, in this review article, the development of metal-mediated chiral catalysts in Mukaiyama-type aldol reaction, reductive aldol reaction and direct aldol reaction are discussed. Moreover, the application of these catalysts in the total synthesis of complex molecules is discussed. (author)

  13. Adverse reactions to drug additives.

    Simon, R A


    There is a long list of additives used by the pharmaceutical industry. Most of the agents used have not been implicated in hypersensitivity reactions. Among those that have, only reactions to parabens and sulfites have been well established. Parabens have been shown to be responsible for rare immunoglobulin E-mediated reactions that occur after the use of local anesthetics. Sulfites, which are present in many drugs, including agents commonly used to treat asthma, have been shown to provoke severe asthmatic attacks in sensitive individuals. Recent studies indicate that additives do not play a significant role in "hyperactivity." The role of additives in urticaria is not well established and therefore the incidence of adverse reactions in this patient population is simply not known. In double-blind, placebo-controlled studies, reactions to tartrazine or additives other than sulfites, if they occur at all, are indeed quite rare for the asthmatic population, even for the aspirin-sensitive subpopulation.

  14. [Mechanisms of cutaneous drug reactions].

    Vaillant, L


    Two main mechanisms, pharmacologic and immunoallergic, are responsible for cutaneous reactions to drugs. Pharmacologic mechanisms can be predictable (overdosage, cumulative or delayed toxicity, adverse effects) or unpredictable (idiosyncratic, intolerance, or anaphylactic reaction). Immunoallergic mechanisms can be mediated by IgE (some types of urticaria and anaphylactic shock), due to circulating immune complexes (leukocytoclastic vasculitis, serum sickness-type reactions) or mediated by lymphocytes (exanthema, Lyell's syndrome, fixed pigmented erythema, photosensitization). The diagnostic work-up varies according to the causative mechanism. When the reaction is predictable, the responsible drug can be identified according to the data in the present bibliography. When the reaction is immunologic, only the chronologic sequence of events can identify the responsible drug. The risk of recurrence with an identical or related molecule also varies according to the causative mechanism. For urticaria, diagnosis and the risk of recurrence differ according to whether the cause is allergic (mediated by IgE or urticarial vasculitis) or is pharmacologic (urticaria due to aspirin or to conversion enzyme inhibitors).

  15. Capture reactions

    Endt, P.M.


    Capture reactions will be considered here from the viewpoint of the nuclear spectroscopist. Especially important to him are the capture of neutrons, protons, and alpha particles, which may proceed through narrow resonances, offering a well defined initial state for the subsequent deexcitation proces

  16. Allergic Reactions

    ... round, they may be caused by exposure to indoor allergens such as dust mites, indoor molds or pets. Urticaria, or hives, is characterized ... home. Video: What is an allergic reaction? » Utility navigation Donate Annual meeting Browse your conditions Check pollen ...

  17. Mediatized Humanitarianism

    Vestergaard, Anne


    The article investigates the implications of mediatization for the legitimation strategies of humanitarian organizations. Based on a (full population) corpus of ~400 pages of brochure material from 1970 to 2007, the micro-textual processes involved in humanitarian organizations' efforts to legiti......The article investigates the implications of mediatization for the legitimation strategies of humanitarian organizations. Based on a (full population) corpus of ~400 pages of brochure material from 1970 to 2007, the micro-textual processes involved in humanitarian organizations' efforts...... legitimation by accountancy, legitimation by institutionalization, and legitimation by compensation. The analysis relates these changes to a problem of trust associated with mediatization through processes of mediation....

  18. Current rectification by mediating electroactive polymers

    Ybarra, Gabriel; Moina, Carlos [Centro de Investigacion sobre Electrodeposicion y Procesos Superficiales, Instituto Nacional de Tecnologia Industrial, CC 157, (1650) San Martin (Argentina); Florit, M. Ines [INIFTA, Facultad de Ciencias Exactas, UNLP, Suc. 4, CC 16, (1900) La Plata (Argentina); Posadas, Dionisio [INIFTA, Facultad de Ciencias Exactas, UNLP, Suc. 4, CC 16, (1900) La Plata (Argentina)], E-mail:


    In this work we briefly review the theoretical basis for the electrochemical rectification in mediated redox reactions at redox polymer modified electrodes. Electrochemical rectification may have two distinct origins. It is either caused by a slow kinetics of the reaction between the external redox couple and the mediator or it is originated by a slow electronic transport within the film under an unfavorable thermodynamic condition. We show experimental results for the redox mediation reaction of poly(o-aminophenol) (POAP) on the Fe{sup 2+/3+} and on the Fe(CN){sub 6}{sup 3-/4-} redox couples in solution that prove the proposed mechanisms of electrochemical rectification.

  19. Biologically mediated dissolution of volcanic glass in seawater

    Staudigel, H; Yayanos, A; Chastain, R; Davies, G.T.; Verdurmen, E.A Th; Schiffmann, P; Bourcier, R; de Baar, H.J.W.


    We studied the effects of biological mediation on the dissolution of basaltic glass in seawater. Experiments with typical seawater microbial populations were contrasted with a sterile control, and reactions were monitored chemically and isotopically. Biologically mediated experiments produce twice

  20. The mechanism of the modified Ullmann reaction

    Sperotto, Elena; Klink, Gerard P.M. van; van Koten, Gerard; Vries, Johannes G. de


    The copper-mediated aromatic nucleophilic substitution reactions developed by Fritz Ullmann and Irma Goldberg required stoichiometric amounts of copper and very high reaction temperatures. Recently, it was found that addition of relatively cheap ligands (diamines, aminoalcohols, diketones, diols) made these reactions truly catalytic, with catalyst amounts as low as 1 mol% or even lower. Since these catalysts are homogeneous, it has opened up the possibility to investigate the mechanism of the...

  1. 顶体反应进程对公猪精液体外受精最佳精卵比的影响%Effect of acrosome reaction progress on optimal sperm/oocyte ratios in IVF of boars

    周华龙; 孙铭菊; 刘世超; 郭佳; 何文腾; 胡魁; 尹智; 刘忠华; 崔卫国


    精液质量参数相似公猪获得相同体外受精(in vitro fertilization,IVF)效果时所需精卵比不同的原因.常规方法鉴定公猪精液质量参数,以不同精卵比进行体外受精并确定不同公猪精液体外受精时的最佳精卵比,分别检测了各公猪精子结合透明带能力、获能及顶体反应状况.3头试验用公猪(A、B和C)精液在精子密度、活率、活力和畸形精子率上无显著差异(P>0.05),17℃保存3d内精子的活率在三者间无差异(P>0.05).3头公猪精液在IVF中达到最佳受精效率时所需的精卵比分别为500∶1、1 000∶1和200∶1.精子结合透明带能力和获能进程检测显示三者无显著差异(P>0.05),但顶体反应进程检测显示三者间具有显著差异(P<0.05).顶体反应进程差异是导致相似精液质量精液之间在IVF中最佳精卵比不同的主要原因.

  2. Complex Mediation

    Bødker, Susanne; Andersen, Peter Bøgh


    This article has its starting point in a large number of empirical findings regarding computer-mediated work. These empirical findings have challenged our understanding of the role of mediation in such work; on the one hand as an aspect of communication and cooperation at work and on the other hand...... as an aspect of human engagement with instruments of work. On the basis of previous work in activity-theoretical and semiotic human—computer interaction, we propose a model to encompass both of these aspects. In a dialogue with our empirical findings we move on to propose a number of types of mediation...... that have helped to enrich our understanding of mediated work and the design of computer mediation for such work....

  3. Síntese de 2-iodobenzamidas e 3-(iodoacetamidobenzamidas ligadas à D-galactose e suas reações de carbociclização radicalar mediadas por hidreto de tri-n-butilestanho Synthesis of 2-iodobenzamides and 3-(iodoacetamidobenzamides linked to D-galactose and their tri-n-butyltin hydride-mediated radical carbocyclization reactions

    Daniel Henriques Soares Leal


    Full Text Available Starting from methyl 6-O-allyl-4-azido-2,3-di-O-benzyl-4-deoxy-α-D-galactopyranoside, four new derivatives containing 2-iodobenzamido and 3-(iodoacetamidobenzamido groups were synthesized. These four compounds were submitted to tri-n-butyltin hydride mediated radical cyclization reactions, resulting in two macrolactams from 11- and 15-endo aryl radical cyclization. The corresponding four hydrogenolysis products were also obtained. The structures of the new compounds were elucidated by ¹H and 13C NMR spectroscopy, DEPT, COSY, HMQC and HMBC experiments.

  4. Mechanisms of severe transfusion reactions.

    Kopko, P M; Holland, P V


    Serious adverse effects of transfusion may be immunologically or non-immunologically mediated. Currently, bacterial contamination of blood products, particularly platelets, is one of the most significant causes of transfusion-related morbidity and mortality. Septic transfusion reactions can present with clinical symptoms similar to immune-mediated hemolytic transfusion reactions and transfusion-related acute lung injury. Extremely high fever and/or gastrointestinal symptoms, in a transfusion recipient, may be indicative of sepsis. The diagnosis is based upon culturing the same organism from both the patient and the transfused blood component. Numerous organisms have been implicated as the cause of septic transfusion reactions. Due to different storage conditions, gram negative organisms are more often isolated from red blood cell components; gram positive organisms are more often isolated from platelets. Prevention of septic transfusion reactions is primarily dependent on an adequate donor history and meticulous preparation of the donor phlebotomy site. Visual inspection of blood components prior to transfusion is also vital to preventing these reactions. Several methods of detection of bacterial contamination and inactivation of pathogens are currently under active investigation.

  5. Spallation reactions; Reactions de spallation

    Cugon, J.


    Spallation reactions dominate the interactions of hadrons with nuclei in the GeV range (from {approx} 0.1 to {approx} 10 GeV). They correspond to a sometimes important ejection of light particles leaving most of the time a residue of mass commensurate with the target mass. The main features of the experimental data are briefly reviewed. The most successful theoretical model, namely the intranuclear cascade + evaporation model, is presented. Its physical content, results and possible improvements are critically discussed. Alternative approaches are shortly reviewed. (author). 84 refs.

  6. Discovery of human posterior head 20 (hPH20) and homo sapiens sperm acrosome associated 1 (hSPACA1) immunocontraceptive epitopes and their effects on fertility in male and female mice.

    Chen, Xuemei; Liu, Xiaodong; Ren, Xiuhua; Li, Xuewu; Wang, Li; Zang, Weidong


    The key goals of immunocontraception research are to obtain full contraceptive effects using vaccines administered to both males and females. Current research concerning human anti-sperm contraceptive vaccines is focused on delineating infertility-related epitopes to avoid autoimmune disease. We constructed phage-display peptide libraries to select epitope peptides derived from human posterior head 20 (hPH20) and homo sapiens sperm acrosome associated 1 (hSPACA1) using sera collected from infertile women harbouring anti-sperm antibodies. Following five rounds of selection, positive colonies were reconfirmed for reactivity with the immunoinfertile sera. We biopanned and analysed the chemical properties of four epitope peptides, named P82, Sa6, Sa37 and Sa76. Synthetic peptides were made and coupled to either bovine serum albumin (BSA) or ovalbumin. We used the BSA-conjugated peptides to immunise BALB/c mice and examined the effects on fertility in female and male mice. The synthetic peptides generated a sperm-specific antibody response in female and male mice that caused a contraceptive state. The immunocontraceptive effect was reversible and, with the disappearance of peptide-specific antibodies, there was complete restoration of fertility. Vaccinations using P82, Sa6 and Sa76 peptides resulted in no apparent side effects. Thus, it is efficient and practical to identify epitope peptide candidates by phage display. These peptides may find clinical application in the specific diagnosis and treatment of male and female infertility and contraceptive vaccine development.

  7. Eicosanoids mediate insect hemocyte migration

    Hemocyte chemotaxis toward infection and wound sites is an essential component of insect defense reactions, although the biochemical signal mechanisms responsible for mediating chemotaxis in insect cells are not well understood. Here we report on the outcomes of experiments designed to test the hyp...

  8. Natural generalized mirage mediation

    Baer, Howard; Barger, Vernon; Serce, Hasan; Tata, Xerxes


    In the supersymmetric scenario known as mirage mediation (MM), the soft supersymmetry (SUSY) breaking terms receive comparable anomaly-mediation and moduli-mediation contributions leading to the phenomenon of mirage unification. The simplest MM SUSY breaking models which are consistent with the measured Higgs mass and sparticle mass constraints are strongly disfavored by fine-tuning considerations. However, while MM makes robust predictions for gaugino masses, the scalar sector is quite sensitive to specific mechanisms for moduli stabilization and potential uplifting. We suggest here a broader setup of generalized mirage mediation (GMM), where heretofore discrete parameters are allowed as continuous to better parametrize these other schemes. We find that natural SUSY spectra consistent with both the measured value of mh as well as LHC lower bounds on superpartner masses are then possible. We explicitly show that models generated from natural GMM may be beyond the reach of even high-luminosity LHC searches. In such a case, the proposed International Linear e+e- Collider will be required for natural SUSY discovery via higgsino pair production reactions. We also outline prospects for detection of higgsino-like WIMPs from natural GMM.

  9. Axion Mediation

    Baryakhtar, Masha; March-Russell, John


    We explore the possibility that supersymmetry breaking is mediated to the Standard Model sector through the interactions of a generalized axion multiplet that gains a F-term expectation value. Using an effective field theory framework we enumerate the most general possible set of axion couplings and compute the Standard Model sector soft-supersymmetry-breaking terms. Unusual, non-minimal spectra, such as those of both natural and split supersymmetry are easily implemented. We discuss example models and low-energy spectra, as well as implications of the particularly minimal case of mediation via the QCD axion multiplet. We argue that if the Peccei-Quinn solution to the strong-CP problem is realized in string theory then such axion-mediation is generic, while in a field theory model it is a natural possibility in both DFSZ- and KSVZ-like regimes. Axion mediation can parametrically dominate gravity-mediation and is also cosmologically beneficial as the constraints arising from axino and gravitino overproduction ...

  10. TEMPO/viologen electrochemical heterojunction for diffusion-controlled redox mediation: a highly rectifying bilayer-sandwiched device based on cross-reaction at the interface between dissimilar redox polymers.

    Tokue, Hiroshi; Oyaizu, Kenichi; Sukegawa, Takashi; Nishide, Hiroyuki


    A couple of totally reversible redox-active molecules, which are different in redox potentials, 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) and viologen (V(2+)), were employed to give rise to a rectified redox conduction effect. Single-layer and bilayer devices were fabricated using polymers containing these sites as pendant groups per repeating unit. The devices were obtained by sandwiching the redox polymer layer(s) with indium tin oxide (ITO)/glass and Pt foil electrodes. Electrochemical measurements of the single-layer device composed of polynorbornene-bearing TEMPO (PTNB) exhibited a diffusion-limited current-voltage response based on the TEMPO(+)/TEMPO exchange reaction, which was almost equivalent to a redox gradient through the PTNB layer depending upon the thickness. The bilayer device gave rise to the current rectification because of the thermodynamically favored cross-reaction between TEMPO(+) and V(+) at the polymer/polymer interface. A current-voltage response obtained for the bilayer device demonstrated a two-step diffusion-limited current behavior as a result of the concurrent V(2+)/V(+) and V(+)/V(0) exchange reactions according to the voltage and suggested that the charge transport process through the device was most likely to be rate-determined by a redox gradient in the polymer layer. Current collection experiments revealed a charge transport balance throughout the device, as a result of the electrochemical stability and robustness of the polymers in both redox states.

  11. Signal enhancement for gene detection based on a redox reaction of [Fe(CN)(6)](4-) mediated by ferrocene at the terminal of a peptide nucleic acid as a probe with hybridization-amenable conformational flexibility.

    Aoki, Hiroshi; Tao, Hiroaki


    Electrochemically enhanced DNA detection was demonstrated by utilizing the couple of a synthesized ferrocene-terminated peptide nucleic acid (PNA) with a cysteine anchor and a sacrificial electron donor [Fe(CN)(6)](4-). DNA detection sensors were prepared by modifying a gold electrode surface with a mixed monolayer of the probe PNA and 11-hydroxy-1-undecanethiol (11-HUT), protecting [Fe(CN)(6)](4-) from any unexpected redox reaction. Before hybridization, the terminal ferrocene moiety of the probe was subject to a redox reaction due to the flexible probe structure and, in the presence of [Fe(CN)(6)](4-), the observed current was amplified based on regeneration of the ferrocene moiety. Hybridization decreased the redox current of the ferrocene. This occurred because hybridization rigidified the probe structure: the ferrocene moiety was then removed from the electrode surface, and the redox reaction of [Fe(CN)(6)](4-) was again prevented. The change in the anodic current before and after hybridization was enhanced 1.75-fold by using the electron donor [Fe(CN)(6)](4-). Sequence-specific detection of the complementary target DNA was also demonstrated.

  12. Synthesis of 4-amino-5-H-2,3-dihydroisothiazole-1,1-dioxide ring systems on sugar templates via carbanion-mediated sulfonamide intramolecular cyclization reactions (CSIC protocols) of glyco-alpha-sulfonamidonitriles.

    Domínguez, Laura; van Nhien, Albert Nguyen; Tomassi, Cyrille; Len, Christophe; Postel, Denis; Marco-Contelles, José


    The carbanion-mediated sulfonate intramolecular cyclizations (CSIC protocols) of glyco-alpha-sulfonamidonitriles derived from readily available monosaccharides have been extensively investigated using potassium carbonate, cesium carbonate, n-BuLi, and LDA as bases. As a result, a series of enantiomerically pure spiro(4-amino-5-H-2,3-dihydroisothiazole-1,1-dioxide) derivatives have been prepared efficiently and isolated in good yield. The synthesis of these new bicyclic systems is key to accessing a novel range of aza analogues of TSAO nucleosides (ATSAOs).

  13. Mediatized Parenthood

    Sonne Damkjær, Maja


    to parenthood? The dissertation explores this question on the basis of a synchronous study within an overall mediatization perspective. The first part of the dissertation focuses on a conceptualization of the relationship between digital media and parenting as well as an exploration of theoretical perspectives...... and methods that make it possible to study the interactions between the two. Concretely, the dissertation builds on a number of key studies within audience research, which have contributed knowledge about the media’s role in the family and the home. This is done by including three approaches to mediatization......) a family-oriented, b) a peer-oriented, c) an oppositional, and d) non-use. Secondary contribution: Based on qualitative audience research and mediatization theory, the dissertation contributes a conceptualization of the relationship between media and parenthood. This is carried out in a study design...

  14. Mediating Business

    "Mediating Business" is a study of the expansion of business journalism. Building on evidence from Denmark, Finland, Norway and Sweden, "Mediating Business" is a comparative and multidisciplinary study of one of the major transformations of the mass media and the realm of business - nationally...... and globally. The book explores the history of key innovations and innovators in the business press. It analyzes changes in the discourse of business journalism associated with the growth in business news and the development of new ways of framing business issues and events. Finally, it examines...... the organizational implications of the increased media visibility of business and, in particular, the development of corporate governance and media relations....

  15. Mediatized play

    Johansen, Stine Liv

    Children’s play must nowadays be understood as a mediatized field in society and culture. Media – understood in a very broad sense - holds severe explanatory power in describing and understanding the practice of play, since play happens both with, through and inspired by media of different sorts....... In this presentation the case of ‘playing soccer’ will be outlined through its different mediated manifestations, including soccer games and programs on TV, computer games, magazines, books, YouTube videos and soccer trading cards....

  16. 叔丁醇钾促进的形成碳—碳及碳—杂键的偶联反应的研究进展%Recent Progress in the Research of the t-BuOK-Mediated Coupling Reactions to Form Carbon-Carbon and Carbon-Heteroatom Bonds

    王良贵; 严国兵; 张鑫燕


    Potassium tert-butoxide has wide application as a strong base and weak nucleophilie in organic chemistry. In this paper, the newest development of the t-BuOK-mediated coupling reactions is reviewed. The main focuses are the formation of carbon-carbon, carbon-ziitrogen and carbon-oxygen bonds. The formation mechanisms of these bonds are discussed in details.%叔丁醇钾由于其碱性强而亲核性相对较弱在有机合成中得到广泛应用.综述了近年来叔丁醇钾促进的交叉偶联反应的研究进展,主要包括碳-碳、碳-氮及碳-氧键的形成及其反应机理的探讨.

  17. Type I hypersensitivity reaction as a complication of lepa

    Janthli, Deepa Manjunath; Chaturvedi, Ashutosh; Somashekar, Shruthi; Lohith, B. A.


    Adverse drug reaction is defined as response to a drug which is noxious and unintended, and which occurs at doses normally used in man for the prophylaxis, diagnosis or therapy of disease, or for the modification of physiological functions. Type I hypersensitivity reaction is known as anaphylactic reaction which is due to immediate immunoglobulin E-mediated reaction. It is characterized by symptoms such as fever nausea, back pain, angiodema, rash, flushing, etc. Lepa generally refers to the a...

  18. Rh(I)-catalyzed transformation of propargyl vinyl ethers into (E,Z)-dienals: stereoelectronic role of trans effect in a metal-mediated pericyclic process and a shift from homogeneous to heterogeneous catalysis during a one-pot reaction.

    Vidhani, Dinesh V; Krafft, Marie E; Alabugin, Igor V


    The combination of experiments and computations reveals unusual features of stereoselective Rh(I)-catalyzed transformation of propargyl vinyl ethers into (E,Z)-dienals. The first step, the conversion of propargyl vinyl ethers into allene aldehydes, proceeds under homogeneous conditions via a "cyclization-mediated" mechanism initiated by Rh(I) coordination at the alkyne. This path agrees well with the small experimental effects of substituents on the carbinol carbon. The key feature revealed by the computational study is the stereoelectronic effect of the ligand arrangement at the catalytic center. The rearrangement barriers significantly decrease due to the greater transfer of electron density from the catalytic metal center to the CO ligand oriented trans to the alkyne. This effect increases electrophilicity of the metal and lowers the calculated barriers by 9.0 kcal/mol. Subsequent evolution of the catalyst leads to the in situ formation of Rh(I) nanoclusters that catalyze stereoselective tautomerization. The intermediacy of heterogeneous catalysis by nanoclusters was confirmed by mercury poisoning, temperature-dependent sigmoidal kinetic curves, and dynamic light scattering. The combination of experiments and computations suggests that the initially formed allene-aldehyde product assists in the transformation of a homogeneous catalyst (or "a cocktail of catalysts") into nanoclusters, which in turn catalyze and control the stereochemistry of subsequent transformations.

  19. Green synthesis of palladium nanoparticles mediated by black tea leaves (Camellia sinensis) extract: Catalytic activity in the reduction of 4-nitrophenol and Suzuki-Miyaura coupling reaction under ligand-free conditions.

    Lebaschi, Sadaf; Hekmati, Malak; Veisi, Hojat


    The present study was conducted to synthesize palladium nanoparticles (Pd NPs) through a facile and green route using non-toxic and renewable natural black tea leaves (Camellia sinensis) extract, as the reducing and stabilizing agent. The as-prepared Pd@B.tea NPs catalyst was characterized by UV-vis spectroscopy, X-ray diffraction (XRD), fourier transformed infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). The Pd@B.tea NPs catalyst could be used as an efficient and heterogeneous catalyst for Suzuki coupling reactions between phenylboronic acid and a range of aryl halides (X=I, Br, Cl) and also the reduction of 4-nitrophenol (4-NP) using sodium borohydride in an environmental friendly medium. Excellent yields of products were obtained with a wide range of substrates and the catalyst was recycled 7 times without any significant loss of its catalytic activity. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. [Allergic and toxic cutaneous reactions to plants].

    Gambillara, Eleonora; Spertini, Francois; Leimgruber, Annette


    Numerous professional or leisure activities expose individuals to plants susceptible to provoke contact allergies. The immunological mechanisms that are responsible for these ailments (delayed cellular reaction linked to allergic dermatitis or immediate IgE mediated reaction of the allergic urticaria) differ according to the plant families involved. A differential diagnosis must be made in the case of the even more frequent non-allergic reactions implying either a simple mechanical irritation, or a contact with toxic substances. The role of UV (phytophotodermatosis), as well as the contact allergy to wood is also evoked in this paper.

  1. Semen collection and polymerase chain reaction-based sex determination of black-headed and straw-necked ibis.

    Kaneko, K; Uematsu, E; Takahashi, Y; Tong, B; Takino, S; Wajiki, Y; Kimura, T; Yamashiro, H; Kaneko, Y; Iwaisaki, H; Sugiyama, T; Yamada, T; Yamagishi, S


    This study aimed to develop a polymerase chain reaction (PCR)-based sexing and effective semen collection methods for black-headed and straw-necked ibis species. However, most birds are not sexually dimorphic, that is, the sexes appear similar. Therefore, the gender should be determined before semen collection. DNA was extracted from the blood samples of 11 black-headed and 4 straw-necked ibis. The sex was determined after PCR amplification of the EE0.6 region of W-chromosome. The PCR products were separated using gel electrophoresis. A single band indicated the presence of the EE0.6 region and that the individual was a female, while no band indicated that the individual was a male. Further, the single bands from seven specimens were amplified. Semen collection was performed by massage or a combination of massage with electro-ejaculation and was attempted during all four seasons. The semen was successfully collected in March from male straw-necked ibis using the massage method. Limited motility, viability and concentration of straw-necked ibis sperm were observed. The sperm length was 180 μm and that of the nucleus was 30 μm with acrosome located at the tip of the nucleus. Thus, the PCR-based sexing proved to be an accurate molecular sexing method for black-headed and straw-necked ibis. Furthermore, we successfully collected semen and observed the stained sperm nucleus and acrosome of the straw-necked ibis sperm. We propose that the use of this PCR methodology can be applied as a routine method for sex determination and semen collection in ibis species for future ecological research. However, considering our limited success, further studies on semen collection method are required.

  2. Catalysis of Photochemical Reactions.

    Albini, A.


    Offers a classification system of catalytic effects in photochemical reactions, contrasting characteristic properties of photochemical and thermal reactions. Discusses catalysis and sensitization, examples of catalyzed reactions of excepted states, complexing ground state substrates, and catalysis of primary photoproducts. (JM)

  3. Snake antivenoms: adverse reactions and production technology

    VM Morais


    Full Text Available Antivenoms have been widely used for more than a century for treating snakebites and other accidents with poisonous animals. Despite their efficacy, the use of heterologous antivenoms involves the possibility of adverse reactions due to activation of the immune system. In this paper, alternatives for antivenom production already in use were evaluated in light of their ability to minimize the occurrence of adverse reactions. These effects were classified according to their molecular mechanism as: anaphylactic reactions mediated by IgE, anaphylactoid reactions caused by complement system activation, and pyrogenic reactions produced mainly by the presence of endotoxins in the final product. In the future, antivenoms may be replaced by humanized antibodies, specific neutralizing compounds or vaccination. Meanwhile, improvements in antivenom quality will be focused on the obtainment of a more purified and specific product in compliance with good manufacturing practices and at an affordable cost.

  4. Selective immediate hypersensitivity reactions to NSAIDs.

    Canto, Maria Gabriela; Andreu, Isabel; Fernandez, Javier; Blanca, Miguel


    Selective immediate reactions to NSAIDs imply that patients develop a urticarial/anaphylactic response to a single drug with good tolerance to other compounds. No systematic review of these reactions has yet been made. With the increase in consumption of NSAIDs, these have become one of the most common drugs inducing hypersensitivity reactions. Although cross-intolerance reactions are the most common, a significant proportion is selective responses. As specific IgE antibodies are not always found, there is only indirect evidence supporting an IgE-mediated mechanism in selective NSAID reactors. Selective immediate reactions to NSAIDs must be considered when a patient develops urticaria or anaphylaxis after intake of one drug with good tolerance to drugs from other groups or even a drug from the same group with a slightly different chemical structure. Further research is required to identify the antigenic determinant structures recognized.

  5. Mechanisms in adverse reactions to food. The ear

    Høst, A


    Otitis media with effusion is rarely caused by allergy to food. Allergic inflammation in the nasal mucosa, mainly due to IgE-mediated reactions to foods, may cause eustachian tube dysfunction and subsequent otitis media with effusion. Inflammatory mediators from the nasal mucosa transported via t...

  6. Air-Driven Potassium Iodide-Mediated Oxidative Photocyclization of Stilbene Derivatives.

    Matsushima, Tomoya; Kobayashi, Sayaka; Watanabe, Soichiro


    A new method has been developed for the potassium iodide-mediated oxidative photocyclization of stilbene derivatives. Compared with conventional iodine-mediated oxidative photocyclization reactions, this new method requires shorter reaction times and affords cyclized products in yields of 45-97%. This reaction proceeds with a catalytic amount of potassium iodide and works in an air-driven manner without the addition of an external scavenger. The radical-mediated oxidative photocyclization of stilbene derivatives using TEMPO was also investigated.

  7. Hypersensitivity reaction to pine nuts (pinon nuts--pignolia).

    Fine, A J


    This report describes two patients with allergic reactions due to the ingestion of pine nuts. Skin testing to the aqueous allergen revealed immediate positive prick test reactions suggesting an IgE-mediated response. No reported cases have been found previously in a review of the medical literature.

  8. Mediated Electron Transfer at Redox Active Monolayers

    Michael E.G. Lyons


    Full Text Available A theoretical model describing the transport and kinetic processes involved in heterogeneous redox catalysis of solution phase reactants at electrode surfaces coated with redox active monolayers is presented. Although the analysis presented has quite general applicability, a specific focus of the paper is concerned with the idea that redox active monolayers can be used to model an ensemble of individual molecular nanoelectrodes. Three possible rate determining steps are considered: heterogeneous electron transfer between immobilized mediator and support electrode ; bimolecular chemical reaction between redox mediator and reactant species in the solution phase, and diffusional mass transport of reactant in solution. A general expression for the steady state reaction flux is derived which is valid for any degree of reversibility of both the heterogeneous electron transfer reaction involving immobilized mediator species and of the bimolecular cross exchange reaction between immobilized mediator and solution phase reactant. The influence of reactant transport in solution is also specifically considered. Simplified analytical expressions for the net reaction flux are derived for experimentally reasonable situations and a kinetic case diagram is constructed outlining the relationships between the various approximate solutions. The theory enables simple diagnostic plots to be constructed which can be used to analyse experimental data.

  9. Radical addition-initiated domino reactions of conjugated oxime ethers.

    Ueda, Masafumi


    The application of conjugated oxime ethers to the synthesis of complex chemical scaffolds using domino radical reactions has been described in detail. The triethylborane-mediated hydroxysulfenylation reaction allows for the regioselective construction of a carbon-sulfur bond and a carbon-oxygen bond in a single operation for the formation of β-hydroxy sulfides. This reaction proceeds via a radical pathway involving regioselective thiyl addition and the subsequent trapping of the resulting α-imino radical with O₂, where the imino group enhances the stability of the intermediate radical. Hydroxyalkylation reactions that occur via a carbon radical addition reaction followed by the hydroxylation of the resulting N-borylenamine with O₂ have also been developed. We investigated sequential radical addition aldol-type reactions in detail to explore the novel domino reactions that occur via the generation of N-borylenamine. The radical reaction of a conjugated oxime ether with triethylborane in the presence of an aldehyde affords γ-butyrolactone via sequential processes including ethyl radical addition, the generation of N-borylenamine, an aldol-type reaction with an aldehyde, and a lactonization reaction. A novel domino reaction has also been developed involving the [3,3]-sigmatropic rearrangement of N-boryl-N-phenoxyenamine. The triethylborane-mediated domino reactions of O-phenyl-conjugated oxime ethers afforded the corresponding benzofuro[2,3-b]pyrrol-2-ones via a radical addition/[3,3]-sigmatropic rearrangement/cyclization/lactamization cascade.

  10. Immunological aspects of nonimmediate reactions to beta-lactam antibiotics.

    Rodilla, Esther Morena; González, Ignacio Dávila; Yges, Elena Laffond; Bellido, Francisco Javier Múñoz; Bara, María Teresa Gracia; Toledano, Félix Lorente


    beta-lactam antibiotics are the agents most frequently implied in immune drug adverse reactions. These can be classified as immediate or nonimmediate according to the time interval between the last drug administration and their onset. Mechanisms of immediate IgE-mediated reactions are widely studied and are therefore better understood. Nonimmediate reactions include a broad number of clinical entities like mild maculopapular exanthemas, the most common, and other less frequent but more severe reactions such as Stevens-Johnson syndrome, toxic epidermal necrolysis, acute exanthematic pustulosis or cytopenias. These nonimmediate reactions are mainly mediated by T cells but the precise underlying mechanisms are not well elucidated. This fact complicates the allergological evaluation of patients with this type of reaction and available tests have demonstrated poor sensitivity and specificity.

  11. Mechanisms in adverse reactions to food. The nose

    Høst, A


    Rhinitis is a common symptom in food allergic patients, but rhinitis is rarely the only symptom. Rhinitis due to adverse reactions to preservatives and colorants is very rare. In anaphylactic systemic reactions to foods the rhinitis symptoms are caused by inflammatory mediators transported...... by the circulation. In non-anaphylactic reactions, the nasal inflammation and symptoms are probably induced by interaction with food allergens transported to the nasal mucosa via the blood circulation....

  12. Carbonyl-Olefin Exchange Reaction and Related Chemistry

    Jossifov, Christo; Kalinova, Radostina

    A new carbon—carbon double bond forming reaction (carbonyl olefin exchange reaction) mediated by transition metal catalytic systems has been discovered. The catalytic systems used (transition metal halides or oxohalides alone or in combination with Lewis acids) are active only in the case when the two reacting groups are in one molecules and are conjugated. In addition these systems accelerate other reactions which run simultaneously with the carbonyl olefin metathesis rendering a detailed investigation of the process very complicated.

  13. Copper-mediated electrophilic imination of alkenylzirconocenes with O-benzoyl ketoximes and aldoximes.

    Liu, Hailan; Yan, Xiaoyu; Chen, Chao; Liu, Qingbin; Xi, Chanjuan


    Copper-mediated electrophilic imination of alkenylzirconocenes generated in situ from alkynes and zirconocenes is accomplished under mild reaction conditions. The reaction can be used to prepare various 2-azadienes.

  14. Case report: anaphylactic reaction to guaifenesin.

    Ray, Manujendra; Faltay, Bela; Haller, Nairmeen Awad


    Adverse drug reactions lead to a significant number of hospital admissions each year and thus contribute to the overall financial burden of health care. Some of these drug reactions are allergic responses. As the overall predictability of allergic responses to drugs remains low, efforts to improve our understanding of the processes underlying these responses continue as we strive toward the ultimate goal of primary prevention. Allergic reactions range from mild pruritic to severe systemic anaphylactic responses. We report a case of a young healthy man who developed an anaphylactic reaction to an over-the-counter expectorant. A skin test showed that the patient had an immunoglobulin E-mediated allergic response to guaifenesin, one of the components of commonly available cough medications. Our review of published literature showed that this is the first report of a severe allergic response to guaifenesin.

  15. Methods for performing electrochemical nitration reactions

    Lister, Tedd Edward; Fox, Robert Vincent


    A method for the electrochemical synthesis of dinitro compounds is disclosed. The method comprises using an anode to oxidize an inactive chemical mediator, such as a ferrocyanide (Fe(CN).sub.6.sup.-4) ion, to an active chemical mediator or oxidizing agent, such as a ferricyanide (Fe(CN).sub.6.sup.-3) ion, in the presence of a differential voltage. The oxidizing agent reacts with a nitro compound and a nitrite ion to form a geminal dinitro compound. The anode may continuously oxidize ferrocyanide to regenerate active ferricyanide, thus keeping sufficient amounts of ferricyanide available for reaction..

  16. Double Pion Production Reactions

    Oset, E; Cano, F; Hernández, E; Kamalov, S S; Nacher, J C; Tejedor, J A G


    We report on reactions producing two pions induced by real and virtual photons or nucleons. The role of different resonances in these reactions is emphasized. Novel results on coherent two pion photoproduction in nuclei are also reported.

  17. Microfluidic chemical reaction circuits

    Lee, Chung-cheng; Sui, Guodong; Elizarov, Arkadij; Kolb, Hartmuth C.; Huang, Jiang; Heath, James R.; Phelps, Michael E.; Quake, Stephen R.; Tseng, Hsian-rong; Wyatt, Paul; Daridon, Antoine


    New microfluidic devices, useful for carrying out chemical reactions, are provided. The devices are adapted for on-chip solvent exchange, chemical processes requiring multiple chemical reactions, and rapid concentration of reagents.

  18. Microscale Thermite Reactions.

    Arnaiz, Francisco J.; Aguado, Rafael; Arnaiz, Susana


    Describes the adaptation of thermite (aluminum with metal oxides) reactions from whole-class demonstrations to student-run micro-reactions. Lists detailed directions and possible variations of the experiment. (WRM)

  19. Chemical transport reactions

    Schäfer, Harald


    Chemical Transport Reactions focuses on the processes and reactions involved in the transport of solid or liquid substances to form vapor phase reaction products. The publication first offers information on experimental and theoretical principles and the transport of solid substances and its special applications. Discussions focus on calculation of the transport effect of heterogeneous equilibria for a gas motion between equilibrium spaces; transport effect and the thermodynamic quantities of the transport reaction; separation and purification of substances by means of material transport; and

  20. First Magnesium-mediated Carbonyl Benzylation in Water

    DENG,Wei(邓维); TAN,Xiang-Hui(谭翔辉); LIU,Lei(刘磊); GUO,Qing-Xiang(郭庆祥)


    Catalyzed by AgNO3, Mg was found for the first time to be able to mediate the coupling reaction between aromatic aldehydes and benzyl bromide or chloride in water. The yields were slightly higher than the recent results for Mg-mediated allylation despite the fact that aqueous benzylation is intrinsically much harder than allylation. It was also found that the coupling reaction was chemoselective for aromatic aldehydes over aliphatic aldehydes, and chemoselective for aromatic aldehydes over aromatic ketones.

  1. Reaction systems with precipitation

    Marek Rogalski


    Full Text Available This article proposes expanding Reaction Systems of Ehrenfeucht and Rozenberg by incorporating precipitation reactions into it. This improves the computing power of Reaction Systems by allowing us to implement a stack. This addition enables us to implement a Deterministic Pushdown Automaton.

  2. Anaphylactic reactions to ingested carmine (E120).

    Wüthrich, B; Kägi, M K; Stücker, W


    We report five cases of anaphylactic reaction to carmine (cochineal, E120) after patients drank an alcoholic beverage. By means of positive skin prick tests (SPT) and positive RAST to carmine. IgE-mediated sensitization could be established. One nonatopic patient showed also a great amount of serum IgE antibodies to the carmine acid-albumin conjugate. Due to its widespread use in the food and cosmetic industry, carmine should be tested in the allergy work-up in case of allergic reactions after a drink or a meal.

  3. Characterization of NAADP-mediated calcium signaling in human spermatozoa

    Sánchez-Tusie, A.A. [Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos (Mexico); Vasudevan, S.R.; Churchill, G.C. [Department of Pharmacology, University of Oxford, Oxford OX1 3QT, England (United Kingdom); Nishigaki, T. [Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos (Mexico); Treviño, C.L., E-mail: [Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos (Mexico)


    Highlights: •Human sperm cells synthesize NAADP. •NAADP-AM mediates [Ca{sup 2+}]{sub i} increases in human sperm in the absence of [Ca{sup 2+}]{sub o}. •Human sperm have two acidic compartments located in the head and midpiece. -- Abstract: Ca{sup 2+} signaling in spermatozoa plays a crucial role during processes such as capacitation and release of the acrosome, but the underlying molecular mechanisms still remain unclear. Nicotinic acid adenine dinucleotide phosphate (NAADP) is a potent Ca{sup 2+}-releasing second messenger in a variety of cellular processes. The presence of a NAADP synthesizing enzyme in sea urchin sperm has been previously reported, suggesting a possible role of NAADP in sperm Ca{sup 2+} signaling. In this work we used in vitro enzyme assays to show the presence of a novel NAADP synthesizing enzyme in human sperm, and to characterize its sensitivity to Ca{sup 2+} and pH. Ca{sup 2+} fluorescence imaging studies demonstrated that the permeable form of NAADP (NAADP-AM) induces intracellular [Ca{sup 2+}] increases in human sperm even in the absence of extracellular Ca{sup 2+}. Using LysoTracker®, a fluorescent probe that selectively accumulates in acidic compartments, we identified two such stores in human sperm cells. Their acidic nature was further confirmed by the reduction in staining intensity observed upon inhibition of the endo-lysosomal proton pump with Bafilomycin, or after lysosomal bursting with glycyl-L-phenylalanine-2-naphthylamide. The selective fluorescent NAADP analog, Ned-19, stained the same subcellular regions as LysoTracker®, suggesting that these stores are the targets of NAADP action.

  4. Plasmon-mediated electrochemical reactions: the influence of nanoparticle structure

    Willets, Katherine A. [Univ. of Texas, Austin, TX (United States)


    This document describes research performed at the University of Texas at Austin under award DE-SC0010307. This award has been transferred to Temple University upon the move of the PI from her original institution to a new institution.

  5. Anapylactoid Reactions Mediated by Autoantibodies to Cholesterol in Miniature Pigs


    eicosanoid secretion. leucopenia , and 20 thrombocytopenia. Hemolytic C titers, and leucocyte and 0 platelet counts were measured before and after...although reduced) and a concom- itant decrease in CO, and the leucopenia and thrombo- vation and this was associated with an anaphylactoid cytopenia

  6. Kiss-induced severe anaphylactic reactions

    Atanasković-Marković Marina


    Full Text Available Introduction. Ingestion is the principal route for food allergens to trigger allergic reaction in atopic persons. However, in some highly sensitive patients severe symptoms may develop upon skin contact and by inhalation. The clinical spectrum ranges from mild facial urticaria and angioedema to life-threatening anaphylactic reactions. Outline of Cases. We describe cases of severe anaphylactic reactions by skin contact, induced by kissing in five children with prior history of severe anaphylaxis caused by food ingestion. These cases were found to have the medical history of IgE mediated food allergy, a very high total and specific serum IgE level and very strong family history of allergy. Conclusion. The presence of tiny particles of food on the kisser's lips was sufficient to trigger an anaphylactic reaction in sensitized children with prior history of severe allergic reaction caused by ingestion of food. Allergic reaction provoked with food allergens by skin contact can be a risk factor for generalized reactions. Therefore, extreme care has to be taken in avoiding kissing allergic children after eating foods to which they are highly allergic. Considering that kissing can be a cause of severe danger for the food allergic patient, such persons should inform their partners about the risk factor for causing their food hypersensitivity.

  7. Silver and gold-catalyzed multicomponent reactions

    Giorgio Abbiati


    Full Text Available Silver and gold salts and complexes mainly act as soft and carbophilic Lewis acids even if their use as σ-activators has been rarely reported. Recently, transformations involving Au(I/Au(III-redox catalytic systems have been reported in the literature. In this review we highlight all these aspects of silver and gold-mediated processes and their application in multicomponent reactions.

  8. A Novel Mechanism for Halogenated Quinone- Mediated and Metal-Independent Organic Fenton-Like Reaction%不依赖于过渡金属离子的卤代醌介导的新型有机类Fenton反应机理

    朱本占; 任福荣; 夏海英; 邵杰


    卤代醌是许多卤芳香持久有机污染物的致癌代谢产物和饮用水消毒副产物.羟基自由基(OH)被公认为生物系统中最具活性的活性氧物种,能导致生物体内DNA等生物大分子的氧化损伤.目前,最被广泛接受的OH产生机理是过渡金属离子催化的Fenton反应.综合采用电子自旋共振二级自旋捕获和其他分析方法,发现四氯苯醌和其它卤代醌皆可通过不依赖于过渡金属离子的途径,显著促进氢过氧化物(H2O2或有机氢过氧化物)的分解而产生OH或烷氧自由基,并首次检测到一种新型的、以碳为中心的醌自由基.基于以上研究,提出一类不依赖于过渡金属离子的卤代醌介导的新型有机类Fenton反应机理.%Halogenated quinones are a class of carcinogenic metabolites of many halogenated persistent organic pollutants and new chlorination disinfection byproducts in drinking water. The hydroxyl radical ("OH) has been considered to be one of the most reactive oxygen species produced in biological systems. It has been shown that 'OH can cause oxidative damage to DNA and other macromolecuies. One of the most widely accepted mechanisms for OH production is through the transition metal-catalyzed Fenton reaction. Through the complementary application of electron spin resonance (ESR) secondary spin-trapping and other analytical methods, we found that tetrachloro-1,4-benzoquinone (TCBQ) and other halogenated quinones could markedly enhance the decomposition of hydroperoxides (H2O2 and organic hydroperoxides) and formation of "OH and alkoxyl radicals independent of transition metal ions. A novel carbon-centered quinone ketoxy radical was also detected and identified for the first time. Based on these data, we proposed a novel mechanism for metal-independent and halogenated quinone-mediated organic Fenton-like reaction.

  9. Palladium-mediated intracellular chemistry

    Yusop, Rahimi M.; Unciti-Broceta, Asier; Johansson, Emma M. V.; Sánchez-Martín, Rosario M.; Bradley, Mark


    Many important intracellular biochemical reactions are modulated by transition metals, typically in the form of metalloproteins. The ability to carry out selective transformations inside a cell would allow researchers to manipulate or interrogate innumerable biological processes. Here, we show that palladium nanoparticles trapped within polystyrene microspheres can enter cells and mediate a variety of Pd0-catalysed reactions, such as allylcarbamate cleavage and Suzuki-Miyaura cross-coupling. The work provides the basis for the customization of heterogeneous unnatural catalysts as tools to carry out artificial chemistries within cells. Such in cellulo synthesis has potential for a plethora of applications ranging from cellular labelling to synthesis of modulators or inhibitors of cell function.

  10. Noncanonical Reactions of Flavoenzymes

    Pablo Sobrado


    Full Text Available Enzymes containing flavin cofactors are predominantly involved in redox reactions in numerous cellular processes where the protein environment modulates the chemical reactivity of the flavin to either transfer one or two electrons. Some flavoenzymes catalyze reactions with no net redox change. In these reactions, the protein environment modulates the reactivity of the flavin to perform novel chemistries. Recent mechanistic and structural data supporting novel flavin functionalities in reactions catalyzed by chorismate synthase, type II isopentenyl diphosphate isomerase, UDP-galactopyranose mutase, and alkyl-dihydroxyacetonephosphate synthase are presented in this review. In these enzymes, the flavin plays either a direct role in acid/base reactions or as a nucleophile or electrophile. In addition, the flavin cofactor is proposed to function as a “molecular scaffold” in the formation of UDP-galactofuranose and alkyl-dihydroxyacetonephosphate by forming a covalent adduct with reaction intermediates.

  11. Reaction kinetics of polybutylene terephthalate polycondensation reaction

    Darda, P. J.; Hogendoorn, J. A.; Versteeg, G. F.; Souren, F.


    The kinetics of the forward polycondensation reaction of polybutylene terephthalate (PBT) has been investigated using thermogravimetric analysis (TGA). PBT - prepolymer with an initial degree of polymerization of 5.5 was used as starting material. The PBT prepolymer was prepared from dimethyl tereph

  12. Transfusion reaction - hemolytic

    ... of allergic transfusion reactions that do not cause hemolysis. ... transfusion, the transfusion must be stopped right away. Blood samples from the recipient (person getting the transfusion) and ...

  13. Desosamine in multicomponent reactions

    Achatz, Sepp; Dömling, Alexander


    Desosamine occurring ubiquitously in natural products is introduced into isocyanide based multicomponent reaction chemistry. Corresponding products are of potential interest for the design of novel antibiotics. © 2006.

  14. Metal-mullite reactions

    Loehman, R.E. [Sandia National Labs., Albuquerque, NM (United States); Tomsia, A.P. [Pask Research and Engineering, Berkeley, CA (United States)


    Mullite was reacted with pure Al and with Ti or Zr dissolved in Ag-Cu eutectic alloys at 1100 C in Ar. Analysis of the Ti and Zr-containing specimens showed reaction zones with compositions of Ti{sub 50}Cu{sub 3O}O{sub 20} and ZrO{sub 2}, respectively. The Al-mullite specimen showed much more extensive penetration into the ceramic and a more diffuse reaction zone than the other two systems. Al{sub 2}O{sub 3} and Si were the main reaction products for Al-mullite reaction.

  15. Reactions at Solid Surfaces

    Ertl, Gerhard


    Expanding on the ideas first presented in Gerhard Ertl's acclaimed Baker Lectures at Cornell University, Reactions at Solid Surfaces comprises an authoritative, self-contained, book-length introduction to surface reactions for both professional chemists and students alike. Outlining our present understanding of the fundamental processes underlying reactions at solid surfaces, the book provides the reader with a complete view of how chemistry works at surfaces, and how to understand and probe the dynamics of surface reactions. Comparing traditional surface probes with more modern ones, and brin

  16. Desosamine in multicomponent reactions

    Achatz, Sepp; Dömling, Alexander


    Desosamine occurring ubiquitously in natural products is introduced into isocyanide based multicomponent reaction chemistry. Corresponding products are of potential interest for the design of novel antibiotics. © 2006.




    Full Text Available : Granulomatous inflammation is a distinctive pattern of chronic inflammatory reaction characterized by microscopic aggregation of activated macrophages which often develop epithelioid appearance and multinucleate giant cells. Granulomas are encountered in limited number of infectious and some non-infectious conditions. Granulomas have been described within the stroma of malignancies like carcinomas of the breast and colon, seminoma and Hodgkin’s lymphoma, where they represent T-cell-mediated reaction of the tumor stroma to antigens expressed by the tumor. Granulomatous reaction in association with renal cell carcinoma (RCC is uncommon, with only few published reports in the literature. We describe a case of conventional (clear cell RCC associated with epithelioid cell granulomas within the tumor parenchyma.

  18. Fluorogenic organocatalytic reactions

    Raeisolsadati Oskouei, M.


    In this thesis, we introduce fluorescence spectroscopy as a new tool to gain insight into the interactions between the substrates and catalyst during organocatalytic reactions. The ultimate goal is to resolve the kinetics of the binding and reaction steps and obtain detailed understanding of the

  19. Chemical burn or reaction

    ... this page: // Chemical burn or reaction To use the sharing features on this page, please enable JavaScript. Chemicals that touch skin can lead to a reaction on the skin, throughout the body, or both. ...

  20. Reactions to Attitudinal Deviancy.

    Levine, John M.; Allen, Vernon L.

    This paper presents a critical review of empirical and theoretical treatments of group reaction to attitudinal deviancy. Inspired by Festinger's (1950) ideas on resolution of attitudinal discrepancies in groups, Schachter (1951) conducted an experiment that has greatly influenced subsequent research and theory concerning reaction to attitudinal…

  1. Allergic reactions to vaccines.

    Wood, Robert A


    Anaphylactic reactions to vaccines are rare but do occur, and have been reported for nearly every vaccine. And while the reaction rate per each dose of vaccine is low, this is a common clinical question due in large part to the enormous numbers of vaccines administered. Reactions are most often due to vaccine constituents rather than the microbial components of the vaccine, but in many instances, the specific ingredient triggering the reaction cannot be definitively identified. Evaluation of patients with suspected vaccine reactions should begin by determining whether the symptoms and timing of the reaction were consistent with a true allergic reaction, followed by an assessment to determine whether the patient needs further doses of the vaccine in question, or similar vaccines, in the future. Skin and serologic testing to vaccines and vaccine constituents can then be performed to further assess the potential cause of the reaction and to develop a plan for future immunizations. Specific guidelines for the administration of influenza vaccines to egg allergic patients have been revised to allow virtually all patients to receive this vaccine in a straightforward manner. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  2. Chemical reaction and separation method

    Jansen, J.C.; Kapteijn, F.; Strous, S.A.


    The invention is directed to process for performing a chemical reaction in a reaction mixture, which reaction produces water as by-product, wherein the reaction mixture is in contact with a hydroxy sodalite membrane, through which water produced during the reaction is removed from the reaction mixtu

  3. Mediators of homologous DNA pairing.

    Zelensky, Alex; Kanaar, Roland; Wyman, Claire


    Homologous DNA pairing and strand exchange are at the core of homologous recombination. These reactions are promoted by a DNA-strand-exchange protein assembled into a nucleoprotein filament comprising the DNA-pairing protein, ATP, and single-stranded DNA. The catalytic activity of this molecular machine depends on control of its dynamic instability by accessory factors. Here we discuss proteins known as recombination mediators that facilitate formation and functional activation of the DNA-strand-exchange protein filament. Although the basics of homologous pairing and DNA-strand exchange are highly conserved in evolution, differences in mediator function are required to cope with differences in how single-stranded DNA is packaged by the single-stranded DNA-binding protein in different species, and the biochemical details of how the different DNA-strand-exchange proteins nucleate and extend into a nucleoprotein filament. The set of (potential) mediator proteins has apparently expanded greatly in evolution, raising interesting questions about the need for additional control and coordination of homologous recombination in more complex organisms. Copyright © 2014 Cold Spring Harbor Laboratory Press; all rights reserved.

  4. mediation: R Package for Causal Mediation Analysis

    Dustin Tingley


    Full Text Available In this paper, we describe the R package mediation for conducting causal mediation analysis in applied empirical research. In many scientific disciplines, the goal of researchers is not only estimating causal effects of a treatment but also understanding the process in which the treatment causally affects the outcome. Causal mediation analysis is frequently used to assess potential causal mechanisms. The mediation package implements a comprehensive suite of statistical tools for conducting such an analysis. The package is organized into two distinct approaches. Using the model-based approach, researchers can estimate causal mediation effects and conduct sensitivity analysis under the standard research design. Furthermore, the design-based approach provides several analysis tools that are applicable under different experimental designs. This approach requires weaker assumptions than the model-based approach. We also implement a statistical method for dealing with multiple (causally dependent mediators, which are often encountered in practice. Finally, the package also offers a methodology for assessing causal mediation in the presence of treatment noncompliance, a common problem in randomized trials.


    Alexander Ponomarev


    Full Text Available This article focuses on the legal model of mediation agreements in Russian and international legislation. The authors consider the main provisions of the mediation agreements in civil matters, in particular, is defined by such features of the legal model as the requirements for this type of agreements. In addition, the article discusses the problematic issues of implementation of mediation agreements.

  6. Mediation as Signal

    Holler, M.J.; Lindner, I.


    This paper analyzes mediation as a signal. Starting from a stylized case, a game theoretical model of one-sided incomplete information, taken from Cho and Kreps (1987), is applied to discuss strategic effects of mediation. It turns out that to reject mediation can be interpreted as a ”negative signa

  7. Mediation in Special Education.

    Fielding, Pamela S.


    This article presents a perspective for viewing mediation in resolving conflicts between parents and school personnel about the education of handicapped students. The appropriateness of mediation as well as its limitations are discussed, as are current uses of mediation in special education and legal problems and issues arising from its use.…

  8. Bayesian Mediation Analysis

    Yuan, Ying; MacKinnon, David P.


    In this article, we propose Bayesian analysis of mediation effects. Compared with conventional frequentist mediation analysis, the Bayesian approach has several advantages. First, it allows researchers to incorporate prior information into the mediation analysis, thus potentially improving the efficiency of estimates. Second, under the Bayesian…

  9. Implementing Nonlinear Feedback Controllers Using DNA Strand Displacement Reactions.

    Sawlekar, Rucha; Montefusco, Francesco; Kulkarni, Vishwesh V; Bates, Declan G


    We show how an important class of nonlinear feedback controllers can be designed using idealized abstract chemical reactions and implemented via DNA strand displacement (DSD) reactions. Exploiting chemical reaction networks (CRNs) as a programming language for the design of complex circuits and networks, we show how a set of unimolecular and bimolecular reactions can be used to realize input-output dynamics that produce a nonlinear quasi sliding mode (QSM) feedback controller. The kinetics of the required chemical reactions can then be implemented as enzyme-free, enthalpy/entropy driven DNA reactions using a toehold mediated strand displacement mechanism via Watson-Crick base pairing and branch migration. We demonstrate that the closed loop response of the nonlinear QSM controller outperforms a traditional linear controller by facilitating much faster tracking response dynamics without introducing overshoots in the transient response. The resulting controller is highly modular and is less affected by retroactivity effects than standard linear designs.

  10. Graphene Layer Growth Chemistry: Five-Six-Ring Flip Reaction

    Whitesides, R.; Domin, D.; Salomon-Ferrer, R.; Lester Jr., W.A.; Frenklach, M.


    Reaction pathways are presented for hydrogen-mediated isomerization of a five and six member carbon ring complex on the zigzag edge of a graphene layer. A new reaction sequence that reverses orientation of the ring complex, or 'flips' it, was identified. Competition between the flip reaction and 'ring separation' was examined. Ring separation is the reverse of the five and six member ring complex formation reaction, previously reported as 'ring collision'. The elementary steps of the pathways were analyzed using density-functional theory (DFT). Rate coefficients were obtained by solution of the energy master equation and classical transition state theory utilizing the DFT energies, frequencies, and geometries. The results indicate that the flip reaction pathway dominates the separation reaction and should be competitive with other pathways important to the graphene zigzag edge growth in high temperature environments.

  11. The Reaction Wheel Pendulum

    Block, Daniel J; Spong, Mark W


    This monograph describes the Reaction Wheel Pendulum, the newest inverted-pendulum-like device for control education and research. We discuss the history and background of the reaction wheel pendulum and other similar experimental devices. We develop mathematical models of the reaction wheel pendulum in depth, including linear and nonlinear models, and models of the sensors and actuators that are used for feedback control. We treat various aspects of the control problem, from linear control of themotor, to stabilization of the pendulum about an equilibrium configuration using linear control, t

  12. Electron transfer reactions

    Cannon, R D


    Electron Transfer Reactions deals with the mechanisms of electron transfer reactions between metal ions in solution, as well as the electron exchange between atoms or molecules in either the gaseous or solid state. The book is divided into three parts. Part 1 covers the electron transfer between atoms and molecules in the gas state. Part 2 tackles the reaction paths of oxidation states and binuclear intermediates, as well as the mechanisms of electron transfer. Part 3 discusses the theories and models of the electron transfer process; theories and experiments involving bridged electron transfe

  13. Involvement of Histamine and RhoA/ROCK in Penicillin Immediate Hypersensitivity Reactions

    Jiayin Han; Yan Yi; Chunying Li; Yushi Zhang; Lianmei Wang; Yong Zhao; Chen Pan; Aihua Liang


    The mechanism of penicillin immediate hypersensitivity reactions has not been completely elucidated. These reactions are generally considered to be mediated by IgE, but penicillin-specific IgE could not be detected in most cases. This study demonstrated that penicillin was able to cause vascular hyperpermeability in a mouse model mimicking clinical symptoms of penicillin immediate hypersensitivity reactions. The first exposure to penicillin also induced immediate edema and exudative reactions...

  14. Recent advances in N-heterocyclic carbene (NHC-catalysed benzoin reactions

    Rajeev S. Menon


    Full Text Available N-Heterocyclic carbenes (NHCs have emerged as a powerful class of organocatalysts that mediate a variety of organic transformations. The Benzoin reaction constitutes one of the earliest known carbon–carbon bond-forming reactions catalysed by NHCs. The rapid growth of NHC catalysis in general has resulted in the development of a variety of benzoin and benzoin-type reactions. An overview of such NHC-catalysed benzoin reactions is presented.

  15. Reaction of Ynamides with Iminoiodinane-Derived Nitrenes: Formation of Oxazolones and Polyfunctionalized Oxazolidinones.

    Rey-Rodriguez, Romain; Grelier, Gwendal; Habert, Loïc; Retailleau, Pascal; Darses, Benjamin; Gillaizeau, Isabelle; Dauban, Philippe


    This article describes the reaction of ynamides with metallanitrenes generated in the presence of an iodine(III) oxidant. N-(Boc)-Ynamides are converted to oxazolones via a cyclization reaction. The reaction is mediated by a catalytic dirhodium-bound nitrene species that first behaves as a Lewis acid. The oxazolones can be converted in a one pot manner to functionalized oxazolidinones following a regio- and stereoselective oxyamination reaction with the same nitrene reagent generated in stoichiometric amounts.

  16. Role of C-type natriuretic peptide in the function of normal human sperm

    Hui Xia


    Full Text Available C-type natriuretic peptide (CNP is a newly discovered type of local regulatory factor that mediates its biological effects through the specific, membrane-bound natriuretic peptide receptor-B (NPR-B. Recent studies have established that CNP is closely related to male reproductive function. The aims of this study were to determine the distribution of CNP/NPR-B in human ejaculated spermatozoa through different methods (such as immunolocalization, real time polymerase chain reaction and Western Blot, and then to evaluate the influence of CNP on sperm function i n vitro, such as motility and acrosome reaction. Human semen samples were collected from consenting donors who met the criteria of the World Health Organization for normozoospermia. Our results show that the specific receptor NPR-B of CNP is localized in the acrosomal region of the head and the membrane of the front-end tail of the sperm, and there is no signal of CNP in human sperm. Compared with the control, CNP can induce a significant dose-dependent increase in spermatozoa motility and acrosome reaction. In summary, CNP/NPR-B can affect sperm motility and acrosome reaction, thus regulating the reproductive function of males. CNP may be a new key factor in regulating sperm function.

  17. Firefighter Nozzle Reaction

    Chin, Selena K.; Sunderland, Peter B.; Jomaas, Grunde


    Nozzle reaction and hose tension are analyzed using conservation of fluid momentum and assuming steady, inviscid flow and a flexible hose in frictionless contact with the ground. An expression that is independent of the bend angle is derived for the hose tension. If this tension is exceeded owing...... to anchor forces, the hose becomes straight. The nozzle reaction is found to equal the jet momentum flow rate, and it does not change when an elbow connects the hose to the nozzle. A forward force must be exerted by a firefighter or another anchor that matches the forward force that the jet would exert...... on a perpendicular wall. Three reaction expressions are derived, allowing it to be determined in terms of hose diameter, jet diameter, flow rate, and static pressure upstream of the nozzle. The nozzle reaction predictions used by the fire service are 56% to 90% of those obtained here for typical firefighting hand...

  18. Oral Hypersensitivity Reactions

    ... food, food additives, drugs, oral hygiene products, and dental materials. Q: Are there any specific foods that are ... dental treatment trigger a hypersensitivity reaction? A: Some dental materials used by the dentist can cause a hypersensitivity ...

  19. Response reactions: equilibrium coupling.

    Hoffmann, Eufrozina A; Nagypal, Istvan


    It is pointed out and illustrated in the present paper that if a homogeneous multiple equilibrium system containing k components and q species is composed of the reactants actually taken and their reactions contain only k + 1 species, then we have a unique representation with (q - k) stoichiometrically independent reactions (SIRs). We define these as coupling reactions. All the other possible combinations with k + 1 species are the coupled reactions that are in equilibrium when the (q - k) SIRs are in equilibrium. The response of the equilibrium state for perturbation is determined by the coupling and coupled equilibria. Depending on the circumstances and the actual thermodynamic data, the effect of coupled equilibria may overtake the effect of the coupling ones, leading to phenomena that are in apparent contradiction with Le Chatelier's principle.

  20. Autocatalysis in reaction networks.

    Deshpande, Abhishek; Gopalkrishnan, Manoj


    The persistence conjecture is a long-standing open problem in chemical reaction network theory. It concerns the behavior of solutions to coupled ODE systems that arise from applying mass-action kinetics to a network of chemical reactions. The idea is that if all reactions are reversible in a weak sense, then no species can go extinct. A notion that has been found useful in thinking about persistence is that of "critical siphon." We explore the combinatorics of critical siphons, with a view toward the persistence conjecture. We introduce the notions of "drainable" and "self-replicable" (or autocatalytic) siphons. We show that: Every minimal critical siphon is either drainable or self-replicable; reaction networks without drainable siphons are persistent; and nonautocatalytic weakly reversible networks are persistent. Our results clarify that the difficulties in proving the persistence conjecture are essentially due to competition between drainable and self-replicable siphons.

  1. Translated chemical reaction networks.

    Johnston, Matthew D


    Many biochemical and industrial applications involve complicated networks of simultaneously occurring chemical reactions. Under the assumption of mass action kinetics, the dynamics of these chemical reaction networks are governed by systems of polynomial ordinary differential equations. The steady states of these mass action systems have been analyzed via a variety of techniques, including stoichiometric network analysis, deficiency theory, and algebraic techniques (e.g., Gröbner bases). In this paper, we present a novel method for characterizing the steady states of mass action systems. Our method explicitly links a network's capacity to permit a particular class of steady states, called toric steady states, to topological properties of a generalized network called a translated chemical reaction network. These networks share their reaction vectors with their source network but are permitted to have different complex stoichiometries and different network topologies. We apply the results to examples drawn from the biochemical literature.

  2. Ofloxacin induced hypersensitivity reaction

    Hari Babu Ramineni


    Full Text Available Ofloxacin is a commonly used antimicrobial agent to combat various infections. The adverse profile of quinolones includes gastrointestinal symptoms, which are the most frequent, neuropsychiatric symptoms, hematologic abnormalities are less common. We report a rare case of ofloxacin induced hypersensitivity reaction in a 57 year old female patient with complaints of rashes over the axilla, upper limb and back, abdomen, thorax associated with exfoliation of skin all over the axilla associated with severe itching. Based on history and clinical examination patient was diagnosed as ofloxacin induced hypersensitivity reaction and was successfully treated with antihistamines and corticosteroids. Pharmacovigilance should be a part of patient care in order to reduce occurrence of adverse drug reaction and also encourage practitioners in reporting so as to gather more and more data regarding adverse drug reactions. [Int J Res Med Sci 2015; 3(1.000: 349-351

  3. Chemisorption And Precipitation Reactions

    The transport and bioavailability of chemical components within soils is, in part, controlled by partitioning between solids and solution. General terms used to describe these partitioning reactions include chemisorption and precipitation. Chemisorption is inclusive of the suit...

  4. Adverse reactions to sulfites

    Yang, William H.; Purchase, Emerson C.R.


    Sulfites are widely used as preservatives in the food and pharmaceutical industries. In the United States more than 250 cases of sulfite-related adverse reactions, including anaphylactic shock, asthmatic attacks, urticaria and angioedema, nausea, abdominal pain and diarrhea, seizures and death, have been reported, including 6 deaths allegedly associated with restaurant food containing sulfites. In Canada 10 sulfite-related adverse reactions have been documented, and 1 death suspected to be sulfite-related has occurred. The exact mechanism of sulfite-induced reactions is unknown. Practising physicians should be aware of the clinical manifestations of sulfite-related adverse reactions as well as which foods and pharmaceuticals contain sulfites. Cases should be reported to health officials and proper advice given to the victims to prevent further exposure to sulfites. The food industry, including beer and wine manufacturers, and the pharmaceutical industry should consider using alternative preservatives. In the interim, they should list any sulfites in their products. PMID:4052897

  5. Allergic reactions in anaesthesia

    Krøigaard, M; Garvey, L H; Menné, T;


    BACKGROUND: The aim of this retrospective survey of possible allergic reactions during anaesthesia was to investigate whether the cause suspected by anaesthetists involved corresponded with the cause found on subsequent investigation in the Danish Anaesthesia Allergy Centre (DAAC). METHODS: Case...... notes and anaesthetic charts from 111 reactions in 107 patients investigated in the DAAC were scrutinized for either suspicions of or warnings against specific substances stated to be the cause of the supposed allergic reaction. RESULTS: In 67 cases, one or more substances were suspected. In 49...... match, the right substance being suspected, but investigations showed an additional allergen or several substances, including the right substance being suspected. CONCLUSIONS: An informed guess is not a reliable way of determining the cause of a supposed allergic reaction during anaesthesia and may put...

  6. Oxygen evolution reaction catalysis

    Haber, Joel A.; Jin, Jian; Xiang, Chengxiang; Gregoire, John M.; Jones, Ryan J.; Guevarra, Dan W.; Shinde, Aniketa A.


    An Oxygen Evolution Reaction (OER) catalyst includes a metal oxide that includes oxygen, cerium, and one or more second metals. In some instances, the cerium is 10 to 80 molar % of the metals in the metal oxide and/or the catalyst includes two or more second metals. The OER catalyst can be included in or on an electrode. The electrode can be arranged in an oxygen evolution system such that the Oxygen Evolution Reaction occurs at the electrode.

  7. Meson production in + reactions

    H Machner; M Betigeri; J Bojowald; A Budzanowski; A Chatterjee; J Ernst; L Freindl; D Frekers; W Garske; K Grewer; A Hamacher; J Ilieva; L Jarczyk; K Kilian; S Kliczewski; W Klimala; D Kolev; T Kutsarova; J Lieb; H Machner; A Magiera; H Nann; L Pentchev; H S Plendl; D Protić; B Razen; P Von Rossen; B J Roy; R Siudak; J Smyrski; R V Srikantiah; A Strzałkowski; R Tsenov; K Zwoll


    Total and differential cross sections for the reactions $p+d → 3He + 0 with = ; and + → 3H + + were measured with the GEM detector at COSY for beam momenta between threshold and the maximum of the corresponding baryon resonance. For both reactions a strong forward–backward asymmetry was found. The data were compared with model calculations. The aspect of isospin symmetry breaking is studied.

  8. Adverse reactions to sulfites

    Yang, William H; Purchase, Emerson C.R.


    Sulfites are widely used as preservatives in the food and pharmaceutical industries. In the United States more than 250 cases of sulfite-related adverse reactions, including anaphylactic shock, asthmatic attacks, urticaria and angioedema, nausea, abdominal pain and diarrhea, seizures and death, have been reported, including 6 deaths allegedly associated with restaurant food containing sulfites. In Canada 10 sulfite-related adverse reactions have been documented, and 1 death suspected to be su...

  9. Catalytic asymmetric umpolung reactions of imines

    Wu, Yongwei; Hu, Lin; Li, Zhe; Deng, Li


    The carbon-nitrogen double bonds in imines are fundamentally important functional groups in organic chemistry. This is largely due to the fact that imines act as electrophiles towards carbon nucleophiles in reactions that form carbon-carbon bonds, thereby serving as one of the most widely used precursors for the formation of amines in both synthetic and biosynthetic settings. If the carbon atom of the imine could be rendered electron-rich, the imine could react as a nucleophile instead of as an electrophile. Such a reversal in the electronic characteristics of the imine functionality would facilitate the development of new chemical transformations that convert imines into amines via carbon-carbon bond-forming reactions with carbon electrophiles, thereby creating new opportunities for the efficient synthesis of amines. The development of asymmetric umpolung reactions of imines (in which the imines act as nucleophiles) remains uncharted territory, in spite of the far-reaching impact such reactions would have in organic synthesis. Here we report the discovery and development of new chiral phase-transfer catalysts that promote the highly efficient asymmetric umpolung reactions of imines with the carbon electrophile enals. These catalysts mediate the deprotonation of imines and direct the 2-azaallyl anions thus formed to react with enals in a highly chemoselective, regioselective, diastereoselective and enantioselective fashion. The reaction tolerates a broad range of imines and enals, and can be carried out in high yield with as little as 0.01 mole per cent catalyst with a moisture- and air-tolerant operational protocol. These umpolung reactions provide a conceptually new and practical approach to chiral amino compounds.

  10. An Expedient Regio- and Diastereoselective Synthesis of Hybrid Frameworks with Embedded Spiro[9,10]dihydroanthracene [9,3′]-pyrrolidine and Spiro[oxindole-3,2′-pyrrolidine] Motifs via an Ionic Liquid-Mediated Multicomponent Reaction

    Natarajan Arumugam


    Full Text Available A series of hitherto unreported anthracene-embedded dispirooxindoles has been synthesized via a one-pot three-component 1,3-dipolar cycloaddition reaction of an azomethine ylide, generated in situ from the reaction of isatin and sarcosine to 10-benzylideneanthracen-9(10H-one as a dipolarophile in 1-butyl-3-methylimidazolium bromide([bmim]Br, an ionic liquid. This reaction proceeded regio- and diastereoselectively, in good to excellent yields.

  11. Accurate Reaction Enthalpies and Sources of Error in DFT Thermochemistry for Aldol, Mannich, and α-Aminoxylation Reactions

    Wheeler, Steven E.; Moran, Antonio; Pieniazek, Susan N.; Houk, K. N.


    Enthalpies for bond-forming reactions that are subject to organocatalysis have been predicted using the high-accuracy CBS-QB3 model chemistry and six DFT functionals. Reaction enthalpies were decomposed into contributions from changes in bonding and other intramolecular effects via the hierarchy of homodesmotic reactions. The order of the reaction exothermicities (aldol < Mannich ≈ α-aminoxylation) arises primarily from changes in formal bond types mediated by contributions from secondary intramolecular interactions. In each of these reaction types, methyl substitution at the β- and γ-positions stabilizes the products relative to the unsubstituted case. The performance of six DFT functionals (B3LYP, B3PW91, B1B95, MPW1PW91, PBE1PBE, and M06-2X), MP2, and SCS-MP2 has been assessed for the prediction of these reaction enthalpies. Even though the PBE1PBE and M06-2X functionals perform well for the aldol and Mannich reactions, errors roughly double when these functionals are applied to the α-aminoxylation reactions. B3PW91 and B1B95, which offer modest accuracy for the aldol and Mannich reactions, yield reliable predictions for the two α-aminoxylation reactions. The excellent performance of the M06-2X and PBE1PBE functionals for aldol and Mannich reactions stems from the cancellation of sizable errors arising from inadequate descriptions of the underlying bond transformations and intramolecular interactions. SCS-MP2/cc-pVTZ performs most consistently across these three classes of reactions, although the reaction exothermicities are systematically underestimated by 1-3 kcal mol-1. Conventional MP2, when paired with the cc-pVTZ basis set, performs somewhat better than SCS-MP2 for some of these reactions, particularly the α-aminoxylations. Finally, the merits of benchmarking DFT functionals for the set of simple chemically meaningful transformations underlying all bond-forming reactions are discussed.

  12. Recent advances in copper-catalyzed asymmetric coupling reactions

    Fengtao Zhou


    Full Text Available Copper-catalyzed (or -mediated asymmetric coupling reactions have received significant attention over the past few years. Especially the coupling reactions of aryl or alkyl halides with nucleophiles became a very powerful tool for the formation of C–C, C–N, C–O and other carbon–heteroatom bonds as well as for the construction of heteroatom-containing ring systems. This review summarizes the recent progress in copper-catalyzed asymmetric coupling reactions for the formation of C–C and carbon–heteroatom bonds.

  13. Reconstitution of DNA strand exchange mediated by Rhp51 recombinase and two mediators.

    Yumiko Kurokawa


    Full Text Available In the fission yeast Schizosaccharomyces pombe, genetic evidence suggests that two mediators, Rad22 (the S. pombe Rad52 homolog and the Swi5-Sfr1 complex, participate in a common pathway of Rhp51 (the S. pombe Rad51 homolog-mediated homologous recombination (HR and HR repair. Here, we have demonstrated an in vitro reconstitution of the central step of DNA strand exchange during HR. Our system consists entirely of homogeneously purified proteins, including Rhp51, the two mediators, and replication protein A (RPA, which reflects genetic requirements in vivo. Using this system, we present the first robust biochemical evidence that concerted action of the two mediators directs the loading of Rhp51 onto single-stranded DNA (ssDNA precoated with RPA. Dissection of the reaction reveals that Rad22 overcomes the inhibitory effect of RPA on Rhp51-Swi5-Sfr1-mediated strand exchange. In addition, Rad22 negates the requirement for a strict order of protein addition to the in vitro system. However, despite the presence of Rad22, Swi5-Sfr1 is still essential for strand exchange. Importantly, Rhp51, but neither Rad22 nor the Swi5-Sfr1 mediator, is the factor that displaces RPA from ssDNA. Swi5-Sfr1 stabilizes Rhp51-ssDNA filaments in an ATP-dependent manner, and this stabilization is correlated with activation of Rhp51 for the strand exchange reaction. Rad22 alone cannot activate the Rhp51 presynaptic filament. AMP-PNP, a nonhydrolyzable ATP analog, induces a similar stabilization of Rhp51, but this stabilization is independent of Swi5-Sfr1. However, hydrolysis of ATP is required for processive strand transfer, which results in the formation of a long heteroduplex. Our in vitro reconstitution system has revealed that the two mediators have indispensable, but distinct, roles for mediating Rhp51 loading onto RPA-precoated ssDNA.

  14. Medication Desensitization: Characterization of Outcomes and Risk Factors for Reactions.

    Murray, Taryn S; Rice, Todd W; Wheeler, Arthur P; Phillips, Elizabeth J; Dworski, Ryszard T; Stollings, Joanna L


    Although its mechanisms are poorly understood, desensitization has been used to induce a temporary state of immune unresponsiveness in patients who have IgE-, non-IgE-, or pharmacologically mediated reactions when a drug has no alternatives. The purpose of this study was to characterize the outcomes and identify risk factors for reactions during drug desensitization. A retrospective review of electronic medical records of adult patients undergoing drug desensitization from January 1, 2011, to December 31, 2013, was conducted in 2 intensive care units at a tertiary medical center. We used multivariate analysis to determine if specified risk factors were associated with reacting during the desensitization. Reactions were classified according to the pretest probability prior to desensitization, and then, reactions during desensitization were classified based on the occurrence of cutaneous reactions as follows: successful with no reaction, mild reaction, moderate reaction, or failed. Failure could result from any systemic allergic or cutaneous reaction resulting in procedure termination. The desensitizations were also assessed to determine if the patient required de-escalation secondary to a reaction. A total of 88 desensitizations were performed in 69 patients. Desensitization was completed with no cutaneous reaction in 85% of patients. No baseline characteristic, medication class (P = 0.46), or indication for desensitization (P = 0.59) was associated with having a reaction. Reported histories of urticaria (P desensitization. However, neither history of urticaria nor labored breathing was independently associated with having a reaction in multivariate analysis (OR = 0.979, 95% CI = 0.325-2.952, P = 0.970, and OR = 1.626, 95% CI = 0.536-4.931, P = 0.739, respectively). Drug desensitization is safe for patients who have no alternative for therapy. Reported allergy histories of urticaria and labored breathing are both associated with having a reaction during the

  15. Immediate reaction to clarithromycin.

    Gangemi, S; Ricciardi, L; Fedele, R; Isola, S; Purello-D'Ambrosio, F


    We present the case of bronchospastic reaction to clarithromycin had during a drug challenge test. Personal allergic history was negative for respiratory allergies and positive for adverse drug reactions to general and regional anesthesia and to ceftriaxone. After the administration of 1/4 of therapeutic dose of clarithromycin the patient showed dyspnea, cough and bronchospasm in all the lung fields. The positivity of the test was confirmed by the negativity to the administration of placebo. The quickness and the clinical characteristic of the adverse reaction suggest a pathogenic mechanism of immediate-type hypersensitivity. On reviewing the literature we have found no reports of bronchospastic reaction to clarithromycin. Macrolides are a class of antibiotics mainly used in the last years in place of beta-lactams because of a broad spectrum of action and a low allergic power. In fact, there are few reports on allergic reactions to these molecules. Clarithromycin is one of the latest macrolides, characterised by the presence of a 14-carbon-atom lactone ring as erythromycin, active on a wide spectrum of pathogens.

  16. Technology-Use Mediation

    Bansler, Jørgen P.; Havn, Erling C.


    This study analyzes how a group of ‘mediators’ in a large, multinational company adapted a computer-mediated communication technology (a ‘virtual workspace’) to the organizational context (and vice versa) by modifying features of the technology, providing ongoing support for users, and promoting...... of technology-use mediation is more complex and indeterminate than earlier literature suggests. In particular, we want to draw attention to the fact that advanced computer-mediated communication technologies are equivocal and that technology-use mediation consequently requires ongoing sensemaking (Weick 1995)....... appropriate conventions of use. Our findings corroborate earlier research on technology-use mediation, which suggests that such mediators can exert considerable influence on how a particular technology will be established and used in an organization. However, this study also indicates that the process...

  17. Chemical kinetics of gas reactions

    Kondrat'Ev, V N


    Chemical Kinetics of Gas Reactions explores the advances in gas kinetics and thermal, photochemical, electrical discharge, and radiation chemical reactions. This book is composed of 10 chapters, and begins with the presentation of general kinetic rules for simple and complex chemical reactions. The next chapters deal with the experimental methods for evaluating chemical reaction mechanisms and some theories of elementary chemical processes. These topics are followed by discussions on certain class of chemical reactions, including unimolecular, bimolecular, and termolecular reactions. The rema

  18. Chemical reactions directed Peptide self-assembly.

    Rasale, Dnyaneshwar B; Das, Apurba K


    Fabrication of self-assembled nanostructures is one of the important aspects in nanoscience and nanotechnology. The study of self-assembled soft materials remains an area of interest due to their potential applications in biomedicine. The versatile properties of soft materials can be tuned using a bottom up approach of small molecules. Peptide based self-assembly has significant impact in biology because of its unique features such as biocompatibility, straight peptide chain and the presence of different side chain functionality. These unique features explore peptides in various self-assembly process. In this review, we briefly introduce chemical reaction-mediated peptide self-assembly. Herein, we have emphasised enzymes, native chemical ligation and photochemical reactions in the exploration of peptide self-assembly.

  19. Radical Reactions and Its Synthetic Application

    Takeaki Naito


    @@ 1Introduction Strategies involving radical reactions have become preeminent tools in organic synthesis. Free radical-mediated cyclization has developed as a powerful method for preparing various types of cyclic compounds via carbon-carbon bond-forming processes. In order to develop effective and convenient methods for the synthesis of biologically active cyclic amines, we have focused our efforts on radical reactions using aldehydes, ketones,and C-C multiple bonds as a radical precursor and/or an oxime ether, hydrazone, and nitrone as a radical acceptor. In this lecture, I would like to talk on radical addition-cyclization of oxime ether and its application to the synthesis of martinellines.

  20. Reaction Qualifications Revisited

    Lippert-Rasmussen, Kasper


    of merit. Specifically, it preserves symmetry between negative evaluations of antimeritocratic bases of selection and negative evaluations of qualifications rooted in comparable antimeritocratic reactions. So if employers should not select among applicants on the basis of their (the employers') racial...... preferences, recipients should not respond to the applicant actually hired on the basis of their (the recipients') racial preferences. My account decomposes the meritocratic ideal into four separate norms, one of which applies to recipients rather than to selectors. Finally, it defends the view that reaction...... reaction-qualifications are entirely irrelevant from the point of view of merit, the view expounded here implies that the ideal of meritocracy and the norm of non-discrimination are less closely tied than theorists like Andrew Mason and David Miller believe.  ...

  1. Nanoparticle Reactions on Chip

    Köhler, J. M.; Kirner, Th.; Wagner, J.; Csáki, A.; Möller, R.; Fritzsche, W.

    The handling of heterogenous systems in micro reactors is difficult due to their adhesion and transport behaviour. Therefore, the formation of precipitates and gas bubbles has to be avoided in micro reaction technology, in most cases. But, micro channels and other micro reactors offer interesting possibilities for the control of reaction conditions and transport by diffusion and convection due to the laminar flow caused by small Reynolds numbers. This can be used for the preparation and modification of objects, which are much smaller than the cross section of microchannels. The formation of colloidal solutions and the change of surface states of nano particles are two important tasks for the application of chip reactors in nanoparticle technology. Some concepts for the preparation and reaction of nanoparticles in modular chip reactor arrangements will be discussed.

  2. Inflammatory reaction in chondroblastoma

    Yamamura, Sigeki [Dept. of Orthopedic Surgery, Nagoya Univ. School of Medicine (Japan); Sato, Keiji [Dept. of Orthopedic Surgery, Nagoya Univ. School of Medicine (Japan); Sugiura, Hideshi [Dept. of Orthopedic Surgery, Nagoya Univ. School of Medicine (Japan); Iwata, Hisashi [Dept. of Orthopedic Surgery, Nagoya Univ. School of Medicine (Japan)


    The objective of this study was to evaluate the inflammatory reaction accompanying chondroblastoma and to define the value of the finding in clinical practice. We reviewed the clinical, radiographic, and magnetic resonance (MR) findings in six patients with histologically proven chondroblastoma. In all cases, MR imaging showered marrow and soft tissue edema. In four of six cases, periosteal reaction related to intra-osseous edema was more clearly demonstrated on MR imaging than on radiographs. Follow-up MR studies after surgery were available in three patients and all showed disappearance of inflammatory responses such as marrow and soft tissue edema, and reactive synovitis. We propose that these inflammatory reactions of chondroblastomas are inportant signs for detecting residual tumor in recurrences after surgery, as well as for making a precise diagnosis. The MR changes may also be valuable in demonstrating eradication of the tumor. (orig./MG)

  3. Hipersensitivity Reactions to Corticosteroids.

    Berbegal, L; DeLeon, F J; Silvestre, J F


    Corticosteroids are widely used drugs in the clinical practice, especially by topic application in dermatology. These substances may act as allergens and produce immediate and delayed hypersensitivity reactions. Allergic contact dermatitis is the most frequent presentation of corticosteroid allergy and it should be studied by patch testing in specific units. The corticosteroids included in the Spanish standard battery are good markers but not ideal. Therefore, if those makers are positive, it is useful to apply a specific battery of corticosteroids and the drugs provided by patients. Immediate reactions are relatively rare but potentially severe, and it is important to confirm the sensitization profile and to guide the use of alternative corticosteroids, because they are often necessary in several diseases. In this article we review the main concepts regarding these two types of hypersensitivity reactions in corticosteroid allergy, as well as their approach in the clinical practice. Copyright © 2015 Elsevier España, S.L.U. and AEDV. All rights reserved.

  4. Adverse reactions to cosmetics

    Dogra A


    Full Text Available Adverse reaction to cosmetics constitute a small but significant number of cases of contact dermatitis with varied appearances. These can present as contact allergic dermatitis, photodermatitis, contact irritant dermatitis, contact urticaria, hypopigmentation, hyperpigmentotion or depigmentation, hair and nail breakage. Fifty patients were included for the study to assess the role of commonly used cosmetics in causing adverse reactions. It was found that hair dyes, lipsticks and surprisingly shaving creams caused more reaction as compared to other cosmetics. Overall incidence of contact allergic dermatitis seen was 3.3% with patients own cosmetics. Patch testing was also done with the basic ingredients and showed positive results in few cases where casual link could be established. It is recommended that labeling of the cosmetics should be done to help the dermatologists and the patients to identify the causative allergen in cosmetic preparation.

  5. Carbon mediated catalysis:A review on oxidative dehydrogenation

    De Chen; Anders Holmen; Zhijun Sui; Xinggui Zhou


    Carbon mediated catalysis has gained an increasing attention in both areas of nanocatalysis and nanomaterials. The progress in carbon nanomaterials provides many new opportunities to manip-ulate the types and properties of active sites of catalysts through manipulating structures, function-alities and properties of carbon surfaces. The present review focuses on progresses in carbon medi-ated oxidative dehydrogenation reactions of ethylbenzene, propane, and butane. The state-of-the-art of the developments of carbon mediated catalysis is discussed in terms of fundamental studies on adsorption of oxygen and hydrocarbons, reaction mechanism as well as effects of carbon nano-material structures and surface functional groups on the catalytic performance. We highlight the importance and challenges in tuning of the electron density of carbon and oxygen on carbon surfac-es for improving selectivity in oxidative dehydrogenation reactions.

  6. N–O Cleavage reactions of heterobicycloalkene-fused 2-isoxazolines

    Jaipal R. Nagireddy


    Full Text Available Transition metal-mediated N–O bond cleavage reactions of heterobicycloalkene-fused 3-methyl-2-isoxazolines were investigated. Optimal cleavage conditions were found with Raney nickel/AlCl3 mediation in aqueous methanol. The reaction provided a diverse collection of novel heterobicycle-fused β-hydroxyketones with good to excellent yields (66–95% and without the need for chromatographic purification.

  7. The Schizosaccharomyces pombe Mediator

    Venturi, Michela

    , Schizosaccharomyces pombe and mammalian Mediator. In our study, we have taken the S. pombe Mediator into consideration and characterized genetically and biochemically two subunits already know in S. cerevisiae, Med9 and Med11, but still not identified in the S. pombe Mediator. Genetic analysis has shown that med9...... complex, but our results did not exclude it completely either. Our attempts to demonstrate the presence of these two subunits in the Mediator complex remain inconclusive primarily due to the lack of proper expression of the tagged versions of the proteins. However, we have paved a way to further...

  8. Knockout reactions: experimental aspects

    Cortina Gil, D. [Santiago de Compostela Univ. (Spain)


    The availability of radioactive beams has given rise to intense activity in the field of direct reactions. The removal of one(two)-nucleon (referred to as nucleon knockout in this text) from a fast exotic projectile has been extensively investigated. This lecture provides a general overview of the experimental results achieved using this technique. The sensitivity of the method to different experimental aspects is illustrated with a few examples. Special attention is given to the application of nucleon-knockout reactions as a general purpose spectroscopic tool. (author)

  9. The role of Zn-alpha2 glycoprotein in sperm motility is mediated by changes in cyclic AMP.

    Qu, Fei; Ying, Xiaoqian; Guo, Wei; Guo, Qiangsu; Chen, Guowu; Liu, Yue; Ding, Zhide


    Sperm motility is essential for male reproduction or natural fertilization. The cyclic AMP (cAMP)/cAMP-dependent protein kinase A (PKA) signaling pathway is generally recognized as one of the significant signaling pathways in the regulation of mammalian spermatozoan motility. Since Zn-alpha2-glycoprotein (ZAG) activity in mammalian adipose tissue is mediated via the beta(3)-adrenoreceptor, with upregulation of the cAMP pathway, we hypothesize that ZAG may play the same role in sperm motility regulation, a new factor of regulation of sperm motility. Therefore, the gene encoding human ZAG was cloned and polyclonal antibodies were generated, and then laser scanning confocal microscopy and flow cytometry were employed to identify this protein in human spermatozoa. The results showed that ZAG protein was mostly localized on the pre-equatorial region covering the acrosome, neck, and middle piece of the flagellum of spermatozoa. Furthermore, using computer-assisted sperm analysis, we found that anti-human ZAG antibodies could significantly reduce the motility of human swim-up spermatozoa after 90- or 120-min incubation (Pspermatozoa and may be involved in the regulation of sperm motility via the cAMP/PKA signaling pathway.

  10. Monocytes mediate shaving of B-cell-bound anti-CD20 antibodies

    Pedersen, Anders Elm; Jungersen, Mette B; Pedersen, Charlotte D


    -mediated cytotoxicity and antibody-dependent cellular cytotoxicity. However, in haematological malignancies, such effector mechanisms can be saturated and result in release of malignant B cells with reduced levels of CD20. It has been hypothesized that this is the result of monocyte-mediated shaving of the CD20/RTX...... to mediate partial inhibition. Also, a series of alternative anti-CD20 antibodies representing both type I and type II antibodies were tested for their ability to induce the shaving reaction. These results demonstrate that a monocyte-mediated shaving reaction can lead to complete loss of most anti-CD20...

  11. The mechanism of the modified Ullmann reaction.

    Sperotto, Elena; van Klink, Gerard P M; van Koten, Gerard; de Vries, Johannes G


    The copper-mediated aromatic nucleophilic substitution reactions developed by Fritz Ullmann and Irma Goldberg required stoichiometric amounts of copper and very high reaction temperatures. Recently, it was found that addition of relatively cheap ligands (diamines, aminoalcohols, diketones, diols) made these reactions truly catalytic, with catalyst amounts as low as 1 mol% or even lower. Since these catalysts are homogeneous, it has opened up the possibility to investigate the mechanism of these modified Ullmann reactions. Most authors agree that Cu(I) is the true catalyst even though Cu(0) and Cu(II) catalysts have also shown to be active. It should be noted however that Cu(I) is capable of reversible disproportionation into Cu(0) and Cu(II). In the first step, the nucleophile displaces the halide in the LnCu(I)X complex forming LnCu(I)ZR (Z = O, NR′, S). Quite a number of mechanisms have been proposed for the actual reaction of this complex with the aryl halide: 1. Oxidative addition of ArX forming a Cu(III) intermediate followed by reductive elimination; 2. Sigma bond metathesis; in this mechanism copper remains in the Cu(II) oxidation state; 3. Single electron transfer (SET) in which a radical anion of the aryl halide is formed (Cu(I)/Cu(II)); 4. Iodine atom transfer (IAT) to give the aryl radical (Cu(I)/Cu(II)); 5. π-complexation of the aryl halide with the Cu(I) complex, which is thought to enable the nucleophilic substitution reaction. Initially, the radical type mechanisms 3 and 4 where discounted based on the fact that radical clock-type experiments with ortho-allyl aryl halides failed to give the cyclised products. However, a recent DFT study by Houk, Buchwald and co-workers shows that the modified Ullmann reaction between aryl iodide and amines or primary alcohols proceeds either via an SET or an IAT mechanism. Van Koten has shown that stalled aminations can be rejuvenated by the addition of Cu(0), which serves to reduce the formed Cu(II) to Cu

  12. Enantioselective Vinylogous Organocascade Reactions.

    Hepburn, Hamish B; Dell'Amico, Luca; Melchiorre, Paolo


    Cascade reactions are powerful tools for rapidly assembling complex molecular architectures from readily available starting materials in a single synthetic operation. Their marriage with asymmetric organocatalysis has led to the development of novel techniques, which are now recognized as reliable strategies for the one-pot enantioselective synthesis of stereochemically dense molecules. In recent years, even more complex synthetic challenges have been addressed by applying the principle of vinylogy to the realm of organocascade catalysis. The key to the success of vinylogous organocascade reactions is the unique ability of the chiral organocatalyst to transfer reactivity to a distal position without losing control on the stereo-determining events. This approach has greatly expanded the synthetic horizons of the field by providing the possibility of forging multiple stereocenters in remote positions from the catalyst's point of action with high selectivity, while simultaneously constructing multiple new bonds. This article critically describes the developments achieved in the field of enantioselective vinylogous organocascade reactions, charting the ideas, the conceptual advances, and the milestone reactions that have been essential for reaching highly practical levels of synthetic efficiency.

  13. Explaining competitive reaction effects

    Leeflang, P.S.H.; Wittink, D.R.

    Changes in promotional expenditure decisions for a brand, as in other marketing decisions, should be based on the expected impact on purchase and consumption behavior as well as on the likely reactions by competitors. Purchase behavior may be predicted from estimated demand functions. Competitive

  14. Reaction product imaging

    Chandler, D.W. [Sandia National Laboratories, Livermore, CA (United States)


    Over the past few years the author has investigated the photochemistry of small molecules using the photofragment imaging technique. Bond energies, spectroscopy of radicals, dissociation dynamics and branching ratios are examples of information obtained by this technique. Along with extending the technique to the study of bimolecular reactions, efforts to make the technique as quantitative as possible have been the focus of the research effort. To this end, the author has measured the bond energy of the C-H bond in acetylene, branching ratios in the dissociation of HI, the energetics of CH{sub 3}Br, CD{sub 3}Br, C{sub 2}H{sub 5}Br and C{sub 2}H{sub 5}OBr dissociation, and the alignment of the CD{sub 3} fragment from CD{sub 3}I photolysis. In an effort to extend the technique to bimolecular reactions the author has studied the reaction of H with HI and the isotopic exchange reaction between H and D{sub 2}.

  15. Cluster knockout reactions

    Arun K Jain; B N Joshi


    Cluster knockout reactions are expected to reveal the amount of clustering (such as that of , d and even of heavier clusters such as 12C, 16O etc.) in the target nucleus. In simple terms, incident medium high-energy nuclear projectile interacts strongly with the cluster (present in the target nucleus) as if it were existing as a free entity. Theoretically, the relatively softer interactions of the two outgoing particles with the residual nucleus lead to optical distortions and are treated in terms of distorted wave (DW) formalism. The long-range projectile–cluster interaction is accounted for, in terms of the finite range (FR) direct reaction formalism, as against the more commonly adopted zero-range (ZR) distorted wave impulse approximation (DWIA) formalism. Comparison of the DWIA calculations with the observed data provide information about the momentum distribution and the clustering spectroscopic factor of the target nucleus. Interesting results and some recent advancements in the area of (, 2) reactions and heavy cluster knockout reactions are discussed. Importance of the finite-range vertex and the final-state interactions are brought out.

  16. Reaction Formulation: A Bibliography.

    Pedrini, D. T.; Pedrini, Bonnie C.

    Reaction formation was studied by Sigmund Freud. This defense mechanism may be related to repression, substitution, reversal, and compensation (or over-compensation). Alfred Adler considered compensation a basic process in his individual psychology. Anna Freud discussed some defense mechanisms, and Bibring, Dwyer, Huntington, and Valenstein…

  17. Explaining competitive reaction effects

    Leeflang, P.S.H.; Wittink, D.R.


    Changes in promotional expenditure decisions for a brand, as in other marketing decisions, should be based on the expected impact on purchase and consumption behavior as well as on the likely reactions by competitors. Purchase behavior may be predicted from estimated demand functions. Competitive re

  18. HF Chain Reaction Laser


    reaction can develop uni2ormly in a subsonic flow with snall teemperatiu-e rise over a distance much longer than the time for mixing, thus tendiný to isolate...upper level population, moreover, the observed effects of H2, Tabla 3, appear to be predicted reasonably well by the model. In the calcula- tions 112

  19. Reactions of Negative Ions


    2 + H2 SO 4 + HS04 (HNO 3 ) 2 + HNO 3 1.1 0.6 * defined as 1 The most important results from an atmospheric viewpoint are the reactions of H SO with NO...constant HS04 >4.5 bracketing 22 0 C1 , 1.95 * 0.25 bracketlng 32 -4 __.. . .___,_=____,,_______... . . . -- . . . . One particularly interesting aspect of

  20. The Gewald multicomponent reaction

    Huang, Yijun; Doemling, Alexander


    The Gewald reaction of sulfur, cyanoacetic acid derivatives, and oxo-component (G-3CR) yielding highly substituted 2-aminothiophene derivatives has seen diverse applications in combinatorial and medicinal chemistry. Its products are of great use in pharmaceutical industry mainly as small molecular w




    Full Text Available OBJECTIVES: Physical exercise provides multiple benefits to an individual. It is known that exercising regularly can prevent coronary heart disease, hypertension and obesity and improve flexibility. The effect of exercise on visual reaction time needs to be studied, a s the existing data on the benefit of aerobic exercise on psychomotor functions is insufficient. MATERIALS AND METHODS: Online Visual reaction time is measured before and after exercise. Subjects were instructed to run on the spot with a springy step in ex aggerated motion for 50 to 60 counts at 2 counts per second, maintaining a constant rhythm. RESULTS: We observed that reaction time was significantly lower after performance of exercise. Individuals reported improved mental alertness, feel good factor, bet ter mood and increase circulation. CONCLUSION: Improving reaction times in sports can help the athlete to optimize his performance in making decisions and increasing attention span for example getting off the starting blocks sooner or successfully making c ontact with the ball. In addition this study shows that use of physical exercise helps improve cognitive function. Exercise proves to be a cheap non pharmacological alternative to improve cognitive performance.

  2. Ruimte voor mediation

    Combrink-Kuiters, L.; Niemeijer, E.; Voert, M. ter


    Dit onderzoek is samen met ADR en mediation Rechterlijke macht gepubliceerd. Het doel was enerzijds na te gaan of, en onder welke condities, mediation in de Nederlandse context een effectief en efficiënt alternatief is voor de gerechtelijke geschillenbeslechting. Anderzijds inzicht te verwerven in d

  3. Teaching Mediated Public Relations.

    Kent, Michael L.


    Discusses approaches to teaching a mediated public relations course, emphasizing the World Wide Web. Outlines five course objectives, assignments and activities, evaluation, texts, and lecture topics. Argues that students mastering these course objectives will understand ethical issues relating to media use, using mediated technology in public…

  4. Dynamic public service mediation

    Hofman, W.; Staalduinen, M. van


    This paper presents an approach to dynamic public service mediation. It is based on a conceptual model and the use of search and ranking algorithms. The conceptual model is based on Abstract State Machine theory. Requirements for dynamic service mediation were derived from a real-world case. The con

  5. The Schizosaccharomyces pombe Mediator

    Venturi, Michela

    In the past several years great attention has been dedicated to the characterization of the Mediator complex in a different range of model organisms. Mediator is a conserved co-activator complex involved in transcriptional regulation and it conveys signals from regulatory transcription factors......+ is a nonessential gene, while deletion of med11+ resulted in unviable cells. These results are in line with those obtained in S. cerevisiae. Isolation of S. pombe Mediator by the tandem affinity purification method and Co-IP experiments lead to the conclusion that Med9 and Med11 might not belong to the Mediator...... complex, but our results did not exclude it completely either. Our attempts to demonstrate the presence of these two subunits in the Mediator complex remain inconclusive primarily due to the lack of proper expression of the tagged versions of the proteins. However, we have paved a way to further...

  6. Music, Radio, and Mediatization

    Krogh, Mads; Michelsen, Morten


    Mediatization has become a key concept for understanding the relations between media and other cultural and social fields. Contributing to the discussions related to the concept of mediatization, this article discusses how practices of radio and music(al life) influence each other. We follow Deacon......’s and Stanyer’s advice to supplement the concept of mediatization with ‘a series of additional concepts at lower levels of abstraction’ and suggest, in this respect, the notion of heterogeneous milieus of music– radio. Hereby, we turn away from the all-encompassing perspectives related to the concept...... of mediatization where media as such seem to be ascribed agency. Instead, we consider historical accounts of music–radio in order to address the complex non- linearity of concrete processes of mediatization as they take place in the multiple meetings between a decentred notion of radio and musical life....

  7. Inorganic Reaction Mechanisms. Part I

    Cooke, D. O.


    Provides a collection of data on the mechanistic aspects of inorganic chemical reactions. Wherever possible includes procedures for classroom demonstration or student project work. The material covered includes gas phase reactions, reactions in solution, mechanisms of electron transfer, the reaction between iron III and iodine, and hydrolysis. (GS)

  8. Dynamics of anion-molecule reactions at low energy

    Mikosch, J.


    Anion-molecule reactions must find their way through deeply bound entrance and exit channel complexes separated by a central barrier. This results in low reaction rates and rich dynamics since direct pathways compete with the formation of transient intermediates. In this thesis we examine the probability of proton transfer to a small anion and transient lifetimes of a thermoneutral bimolecular nucleophilic substitution (S{sub N}2) reaction at well defined variable temperature down to 8 Kelvin in a multipole trap. The observed strong inverse temperature dependence is attributed to the deficit of available quantum states in the entrance channel at decreasing temperature. Furthermore we investigate scattering dynamics of S{sub N}2 reactions at defined relative energy between 0.4 and 10 eV by crossed beam slice imaging. A weakly exothermic reaction with high central barrier proceeds via an indirect, complex-mediated mechanism at low relative energies featuring high internal product excitation in excellent quantitative agreement with a statistical model. In contrast, direct backward scattering prevails for higher energies with product velocities close to the kinematical cutoff. For a strongly exothermic reaction, competing S{sub N}2-, dihalide- and proton transfer-channels are explored which proceed by complex mediation for low energy and various rebound-, grazing- and collision induced bond rupture-mechanisms at higher energy. From our data and a collaboration with theory we identify a new indirect roundabout S{sub N}2 mechanism involving CH{sub 3}-rotation. (orig.)

  9. Laboratory simulation of natural sulphurization: II. Reaction of multifunctionalized lipids with inorganic polysulphides at low temperatures

    Sinninghe Damsté, J.S.; Schouten, S.; Graaf, W. de; Driel, G.B. van


    A number of geochemically relevant model compounds (alkenes, ketones, aldehydes, acids, alcohols and esters) have been subjected to a reaction with sodium hydrogen polysulphide either in one solvent or mediated by a phase transfer reagent. This reaction, referred to as the hydrosulphurization

  10. Reaction chemistry of cerium



    It is truly ironic that a synthetic organic chemist likely has far greater knowledge of the reaction chemistry of cerium(IV) than an inorganic colleague. Cerium(IV) reagents have long since been employed as oxidants in effecting a wide variety of organic transformations. Conversely, prior to the late 1980s, the number of well characterized cerium(IV) complexes did not extend past a handful of known species. Though in many other areas, interest in the molecular chemistry of the 4f-elements has undergone an explosive growth over the last twenty years, the chemistry of cerium(IV) has for the most part been overlooked. This report describes reactions of cerium complexes and structure.

  11. Reaction chemistry of cerium



    It is truly ironic that a synthetic organic chemist likely has far greater knowledge of the reaction chemistry of cerium(IV) than an inorganic colleague. Cerium(IV) reagents have long since been employed as oxidants in effecting a wide variety of organic transformations. Conversely, prior to the late 1980s, the number of well characterized cerium(IV) complexes did not extend past a handful of known species. Though in many other areas, interest in the molecular chemistry of the 4f-elements has undergone an explosive growth over the last twenty years, the chemistry of cerium(IV) has for the most part been overlooked. This report describes reactions of cerium complexes and structure.

  12. Photooxidative reactions of psoralens

    Potapenko, A.Ya.; Sukhorukov, V.L. (Vtoroj Moskovskij Gosudarstvennyj Meditsinskij Inst. (USSR))


    The mechanism and biological significance of photooxidative reactions of psoralens are reviewed. Skin-photosensitizing activities of bifunctional and monofunctional psoralens are compared. Antioxidants tocopherols and butilated hydroxytoluene inhibit photochemical reactions of psoralens responsible for induction of erythema. The same antioxidants do not inhibit PUVA-therapy of psriasis. Though psoralens can generate singlet oxygen under UVA-irradiation (315 - 400 nm), nevertheless singlet oxygen does not play a significant role in 8-methoxypsoralen (8-MOP) sensitized photooxidation of tocopherol or dihydroxyphenylalanine (DOPA). SH-compounds enhance the rate of 8-MOP sensitized photooxidation of DOPA by a factor of four, simultaneously the rate of oxidation of SH-groups is enhanced many fold in the presence of DOPA. Under UVA-irradiation in organic solvents psoralens are photooxidized. Dimeric photooxidized psoralens are easily destructed in water medium, their destruction induce oxidation of unsaturated lipids and DOPA.

  13. Oral muscle relaxant may induce immediate allergic reactions.

    Hur, Gyu-Young; Hwang, Eui Kyung; Moon, Jae-Young; Ye, Young-Min; Shim, Jae-Jeong; Park, Hae-Sim; Kang, Kyung-Ho


    Eperisone and afloqualone act by relaxing both skeletal and vascular smooth muscles to improve circulation and suppress pain reflex. These drugs are typically prescribed with non-steroidal anti-inflammatory drugs (NSAIDs) as painkillers. However, there have been no reports on serious adverse reactions to oral muscle relaxants; and this is the first report to describe three allergic reactions caused by eperisone and afloqualone. All three patients had histories of allergic reactions after oral intake of multiple painkillers, including oral muscle relaxants and NSAIDs, for chronic muscle pain. An open-label oral challenge test was performed with each drug to confirm which drugs caused the systemic reactions. All patients experienced the same reactions within one hour after oral intake of eperisone or afloqualone. The severity of these reactions ranged from laryngeal edema to hypotension. To confirm that the systemic reaction was caused by eperisone or afloqualone, skin prick testing and intradermal skin tests were performed with eperisone or afloqualone extract in vivo, and basophil activity tests were performed after stimulation with these drugs in vitro. In one patient with laryngeal edema, the intradermal test with afloqualone extract had a positive result, and CD63 expression levels on basophils increased in a dose-dependent manner by stimulation with afloqualone. We report three allergic reactions caused by oral muscle relaxants that might be mediated by non-immunoglobulin E-mediated responses. Since oral muscle relaxants such as eperisone and afloqualone are commonly prescribed for chronic muscle pain and can induce severe allergic reactions, we should prescribe them carefully.

  14. Photochemical reaction dynamics

    Moore, B.C. [Lawrence Berkeley Laboratory, Livermore, CA (United States)


    The purpose of the program is to develop a fundamental understanding of unimolecular and bimolecular reaction dynamics with application in combustion and energy systems. The energy dependence in ketene isomerization, ketene dissociation dynamics, and carbonyl substitution on organometallic rhodium complexes in liquid xenon have been studied. Future studies concerning unimolecular processes in ketene as well as energy transfer and kinetic studies of methylene radicals are discussed.

  15. Urea hydrolysis and calcium carbonate reaction fronts

    Fox, D. T.; Redden, G. D.; Henriksen, J.; Fujita, Y.; Guo, L.; Huang, H.


    The mobility of toxic or radioactive metal contaminants in subsurface environments can be reduced by the formation of mineral precipitates that form co-precipitates with the contaminants or that isolate them from the mobile fluid phase. An engineering challenge is to control the spatial distribution of precipitation reactions with respect to: 1) the location of a contaminant, and 2) where reactants are introduced into the subsurface. One strategy being explored for immobilizing contaminants, such as Sr-90, involves stimulating mineral precipitation by forming carbonate ions and hydroxide via the in situ, microbially mediated hydrolysis of urea. A series of column experiments have been conducted to explore how the construction or design of such an in situ reactant production strategy can affect the temporal and spatial distribution of calcium carbonate precipitation, and how the distribution is coupled to changes in permeability. The columns were constructed with silica gel as the porous media. An interval midway through the column contained an adsorbed urease enzyme in order to simulate a biologically active zone. A series of influent solutions were injected to characterize hydraulic properties of the column (e.g., bromide tracer), profiles of chemical conditions and reaction products as the enzyme catalyzes urea hydrolysis (e.g., pH, ammonia, urea), and changes that occur due to CaCO3 precipitation with the introduction of a calcium+urea solutions. In one experiment, hydraulic conductivity was reduced as precipitate accumulated in a layer within the column that had a higher fraction of fine grained silica gel. Subsequent reduction of permeability and flow (for a constant head condition) resulted in displacement of the hydrolysis and precipitation reaction profiles upstream. In another experiment, which lacked the physical heterogeneity (fine grained layer), the precipitation reaction did not result in loss of permeability or flow velocity and the reaction profile

  16. [Mediation in health].

    Decastello, Alice


    The author presents mediation as an alternative dispute resolution method. Mediation is a process where the parties are ready to settle their dispute out of court, by way of negotiation and with the involvement of an independent third person as mediator. In the mediation process the mediator shall not decide the dispute, nor examine the default or give legal advice or express his/her opinion - the mediator's duty is to help the parties bring their positions closer and come to a settlement agreement within a short time (120 days). The author gives a summary of the applications of the Hungarian Act on Mediation in Public Health and draws conclusions from the practical experience since entry into force of the legislation and illustrates the advantages of mediation over the court procedure (which may drag on for years). The primary advantages of mediation are that both the mediators and the parties are bound by the obligation of secrecy, the procedure is cheaper than the court proceedings, and the parties can "save their faces" because in mediation the winner-winner formula asserts itself - against lawsuits where the winner-loser positions are confronted. The author also analyses the specific data and information available so far. As for the future, the legislation needs to be amended at several points. It is particularly expedient to regulate the legal relationship between the insurance companies and the health service providers because the liability insurance may not cover the damages the courts adjudicate. And so some of the service providers may go bankrupt as the difference in excess of the upper limit of coverage - it might as well be up to HUF 5 million per case - shall be paid from own budget, to the charge of the upkeep costs. It is also required to review and amend the regulations on expert activities, just as it is inevitable to make data supply compulsory - otherwise it will be impossible to monitor the number of mediation procedures in health. At present

  17. General resonance mediation

    McGarrie, Moritz


    We extend the framework of general gauge mediation to cases where the mediating fields have a nontrivial spectral function, as might arise from strong dynamics. We demonstrate through examples that this setup describes a broad class of possible models of gauge mediated supersymmetry breaking. A main emphasis is to give general formulas for cross sections for {sigma}(visible {yields} hidden) in these resonance models. We will also give formulas for soft masses, A-terms and demonstrate the framework with a holographic setup.

  18. Anger and health in dementia caregivers: exploring the mediation effect of optimism.

    López, J; Romero-Moreno, R; Márquez-González, M; Losada, A


    Although previous studies indicate a negative association between caregivers' anger and health, the potential mechanisms linking this relationship are not yet fully understood. The aim of this study was to explore the potential mediating role of optimism in the relationship between anger and caregivers' physical health. Dementia caregivers (n = 108) were interviewed and filled out instruments assessing their anger (reaction), optimism and health (vitality). A mediational model was tested to determine whether optimism partially mediated the relationship between anger and vitality. Angry reaction was negatively associated with optimism and vitality; optimism was positively associated with vitality. Finally, the relationship between angry reaction and vitality decreased when optimism was entered simultaneously. A non-parametric bootstrap approach confirmed that optimism significantly mediated some of the relationship between angry reaction and vitality. These findings suggest that low optimism may help explain the association between caregivers' anger and reduced sense of vitality. The results provide a specific target for intervention with caregivers.

  19. Copper-mediated amidation of alkenylzirconocenes with acyl azides: formation of enamides.

    Liu, Hailan; Zhou, Yiqing; Yan, Xiaoyu; Chen, Chao; Liu, Qingbin; Xi, Chanjuan


    Copper-mediated amidation of alkenylzirconocenes generated in situ from alkynes and zirconocenes with acyl azides is accomplished under mild conditions. The reaction can be used to prepare various enamides.

  20. Acute coronary syndrome in diclofenac sodium-induced type I hypersensitivity reaction : Kounis syndrome

    Gluvic, Zoran M.; Putnikovic, Biljana; Panic, Milos; Stojkovic, Aleksandra; Rasic-Milutinovic, Zorica; Jankovic-Gavrilovic, Jelena


    Drug-induced type I hypersensitivity reactions are frequent. Sometimes, acute coronary syndrome (ACS) can be registered in such patients, which may have a serious impact on the course and management of the allergic reaction. Because of potentially atypical ACS clinical presentations, the ECG is an obligatory diagnostic tool in any allergic reaction. Coronary artery spasm is the pathophysiological basis of ACS, triggered by the action of potent vasoactive mediators (histamine, neutral protease...

  1. Egg jelly of the newt, Cynops pyrrhogaster contains a factor essential for sperm binding to the vitelline envelope.

    Hiyoshi, Wataru; Sasaki, Takayuki; Takayama-Watanabe, Eriko; Takai, Hiroyuki; Watanabe, Akihiko; Onitake, Kazuo


    The acrosome reaction of newt sperm is induced at the surface of egg jelly and the acrosome-reacted sperm acquire the ability to bind to the vitelline envelope. However, because the substance that induces the acrosome reaction has not been identified, the mechanism by which the acrosome-reacted sperm bind to the vitelline envelope remains unclear. We found here that a Dolichos biforus agglutinin (DBA) specifically mimicked the acrosome reaction immediately upon its addition in the presence of milimolar level Ca(2+). Fluorescein isothiocyanate-labeled DBA bound specifically to the acrosomal cap of the intact sperm in the presence of a Ca(2+)-chelating agent, EDTA, suggesting that binding of DBA to the native receptor for the egg jelly substance on the acrosomal region took the place of the egg jelly substance-induced acrosome reaction. In contrast, the sperm that had been acrosome reacted by DBA treatment did not bind to the vitelline envelope of the egg whose jelly layers were removed. Subsequent addition of jelly extract caused the sperm binding to vitelline envelope, indicating that the egg jelly of the newt contains substances that are involved in not only inducing the acrosome reaction but also binding to the vitelline envelope. This is the first demonstration of the involvement of egg jelly substance in the binding of acrosome-reacted sperm to the vitelline envelope.

  2. Overexpressing sperm surface beta 1,4-galactosyltransferase in transgenic mice affects multiple aspects of sperm-egg interactions


    Sperm surface beta 1,4-galactosyltransferase (GalTase) mediates fertilization in mice by binding to specific O-linked oligosaccharide ligands on the egg coat glycoprotein ZP3. Before binding the egg, sperm GalTase is masked by epididymally derived glycosides that are shed from the sperm surface during capacitation. After binding the egg, sperm- bound oligosaccharides on ZP3 induce the acrosome reaction by receptor aggregation, presumably involving GalTase. In this study, we asked how increasi...

  3. Technology-Use Mediation

    Bansler, Jørgen P.; Havn, Erling C.


    Implementation of new computer-mediated communication (CMC) systems in organizations is a complex socio-technical endeavour, involving the mutual adaptation of technology and organization over time. Drawing on the analytic concept of sensemaking, this paper provides a theoretical perspective...... that deepens our understanding of how organizations appropriate new electronic communication media. The paper analyzes how a group of mediators in a large, multinational company adapted a new web-based CMC technology (a virtual workspace) to the local organizational context (and vice versa) by modifying...... features of the technology, providing ongoing support for users, and promoting appropriate conventions of use. We found that these mediators exerted considerable influence on how the technology was established and used in the organization. The mediators were not neutral facilitators of a well...

  4. Natural generalized mirage mediation

    Baer, Howard; Serce, Hasan; Tata, Xerxes


    In the supersymmetric scenario known as mirage mediation (MM), the soft SUSY breaking terms receive comparable anomaly-mediation and moduli-mediation contributions leading to the phenomenon of mirage unification. The simplest MM SUSY breaking models which are consistent with the measured Higgs mass and sparticle mass constraints are strongly disfavoured by fine-tuning considerations. However, while MM makes robust predictions for gaugino masses, the scalar sector is quite sensitive to specific mechanisms for moduli stabilization and potential uplifting. We suggest here a broader setup of generalized mirage mediation (GMM), where heretofore discrete parameters are allowed as continuous to better parametrize these other schemes. We find that natural SUSY spectra consistent with both the measured value of m(h). as well as LHC lower bounds on superpartner masses are then possible. We explicitly show that models generated from natural GMM may be beyond the reach of even high-luminosity LHC searches. In such a case...

  5. Well sealing via thermite reactions

    Lowry, William Edward; Dunn, Sandra Dalvit


    A platform is formed in a well below a target plug zone by lowering a thermite reaction charge into the well and igniting it, whereby the products of the reaction are allowed to cool and expand to form a platform or support in the well. A main thermite reaction charge is placed above the platform and ignited to form a main sealing plug for the well. In some embodiments an upper plug is formed by igniting an upper thermite reaction charge above the main thermite reaction charge. The upper plug confines the products of ignition of the main thermite reaction charge.

  6. DREDed Anomaly Mediation

    Boyda, E; Pierce, A T; Boyda, Ed; Murayama, Hitoshi; Pierce, Aaron


    We offer a guide to dimensional reduction (DRED) in theories with anomaly mediated supersymmetry breaking. Evanescent operators proportional to epsilon arise in the bare Lagrangian when it is reduced from d=4 to d= (4-2 epsilon) dimensions. In the course of a detailed diagrammatic calculation, we show that inclusion of these operators is crucial. The evanescent operators conspire to drive the supersymmetry-breaking parameters along anomaly-mediation trajectories across heavy particle thresholds, guaranteeing the ultraviolet insensitivity.

  7. Reaction rate in an evanescent random walkers system

    Ré, Miguel A


    Diffusion mediated reaction models are particularly ubiquitous in the description of physical, chemical or biological processes. The random walk schema is a useful tool for formulating these models. Recently, evanescent random walk models have received attention in order to include finite lifetime processes. For instance, activated chemical reactions, such as laser photolysis, exhibit a different asymptotic limit when compared with immortal walker models. A diffusion limited reaction model based on a one dimensional continuous time random walk on a lattice with evanescent walkers is presented here. The absorption probability density and the reaction rate are analytically calculated in the Laplace domain. A finite absorption rate is considered, a model usually referred to as imperfect trapping. Short and long time behaviors are analyzed.

  8. Ceruloplasmin decreases respiratory burst reaction during pregnancy.

    Varfolomeeva, Elena Y; Semenova, Elena V; Sokolov, Alexey V; Aplin, Kirill D; Timofeeva, Kseniya E; Vasilyev, Vadim B; Filatov, Michael V


    Testing of pregnant women reveals weakening of neutrophil-mediated effector functions, such as reactive oxygen species generation. This study provides data confirming the phenomenon, gained through application of the flow cytometry technique. Key factors influencing neutrophil functional activity in blood plasma of pregnant women have not been detected so far. At the same time, concentration of ceruloplasmin - a copper-containing glycoprotein - is known to increase in blood significantly during pregnancy. We observed the negative correlation between ceruloplasmin concentration in blood plasma of pregnant women and the intensity of respiratory burst of neutrophils. Fractionation of plasma using gel-filtration revealed that ceruloplasmin-containing fraction demonstrated suppression of the respiratory burst reaction. Partial elimination of ceruloplasmin from the blood of pregnant women, performed with the help of specific antibodies and followed by immunoprecipitation, leads to an increased respiratory burst reaction. On the contrary, addition of ceruloplasmin to blood samples of healthy donors noticeably decreases the respiratory burst reaction. The results presented prove that change in ceruloplasmin level in plasma is necessary and sufficient for modulating the ability of neutrophils to produce reactive oxygen species during pregnancy.

  9. Insect bite reactions

    Sanjay Singh


    Full Text Available Insects are a class of living creatures within the arthropods. Insect bite reactions are commonly seen in clinical practice. The present review touches upon the medically important insects and their places in the classification, the sparse literature on the epidemiology of insect bites in India, and different variables influencing the susceptibility of an individual to insect bites. Clinical features of mosquito bites, hypersensitivity to mosquito bites Epstein-Barr virus NK (HMB-EBV-NK disease, eruptive pseudoangiomatosis, Skeeter syndrome, papular pruritic eruption of HIV/AIDS, and clinical features produced by bed bugs, Mexican chicken bugs, assassin bugs, kissing bugs, fleas, black flies, Blandford flies, louse flies, tsetse flies, midges, and thrips are discussed. Brief account is presented of the immunogenic components of mosquito and bed bug saliva. Papular urticaria is discussed including its epidemiology, the 5 stages of skin reaction, the SCRATCH principle as an aid in diagnosis, and the recent evidence supporting participation of types I, III, and IV hypersensitivity reactions in its causation is summarized. Recent developments in the treatment of pediculosis capitis including spinosad 0.9% suspension, benzyl alcohol 5% lotion, dimethicone 4% lotion, isopropyl myristate 50% rinse, and other suffocants are discussed within the context of evidence derived from randomized controlled trials and key findings of a recent systematic review. We also touch upon a non-chemical treatment of head lice and the ineffectiveness of egg-loosening products. Knockdown resistance (kdr as the genetic mechanism making the lice nerves insensitive to permethrin is discussed along with the surprising contrary clinical evidence from Europe about efficacy of permethrin in children with head lice carrying kdr-like gene. The review also presents a brief account of insects as vectors of diseases and ends with discussion of prevention of insect bites and some

  10. The Role of Psychological Stress Reactions in the Longitudinal Relation Between Workplace Bullying and Turnover

    Nabe-Nielsen, Kirsten; Grynderup, Matias Brødsgaard; Conway, Paul Maurice


    OBJECTIVES: To investigate the association between workplace bullying and change of job/unemployment, and to investigate whether psychological stress reactions constitute a potential pathway linking workplace bullying and change of job/unemployment. METHODS: We used questionnaire data on workplace...... bullying and psychological stress reactions and register data on change of job/unemployment. We applied a multiple pathway approach to estimate the proportion of the association between workplace bullying and subsequent change of job/unemployment that was potentially mediated by psychological stress...... reactions. RESULTS: Workplace bullying was associated with risk of change of job (odds ratio [OR] = 1.35; 95% confidence interval [CI]: 1.06-1.72; 24% potentially mediated by psychological stress reactions) and unemployment (OR = 4.90; 95% CI: 3.18-7.55; 19% potentially mediated by psychological stress...

  11. Organocatalytic Enantioselective Henry Reactions

    Raquel P. Herrera


    Full Text Available A large number of interesting organocatalytic enantioselective protocols have been explored and successfully applied in the last decade. Among them, the Henry (nitroaldol reaction represents a powerful carbon-carbon bond-forming procedure for the preparation of valuable synthetic intermediates, such as enantioenriched nitro alcohols, which can be further transformed in a number of important nitrogen and oxygen-containing compounds. This area of research is still in expansion and a more complex version of this useful process has recently emerged, the domino Michael/Henry protocol, affording highly functionalized cycles with multiple stereogenic centers.

  12. Multispecies pair annihilation reactions.

    Deloubrière, Olivier; Hilhorst, Henk J; Täuber, Uwe C


    We consider diffusion-limited reactions A(i)+A(j)--> (12 and d> or =2, we argue that the asymptotic density decay for such mutual annihilation processes with equal rates and initial densities is the same as for single-species pair annihilation A+A-->. In d=1, however, particle segregation occurs for all q< infinity. The total density decays according to a q dependent power law, rho(t) approximately t(-alpha(q)). Within a simplified version of the model alpha(q)=(q-1)/2q can be determined exactly. Our findings are supported through Monte Carlo simulations.

  13. Low Energy Nuclear Reactions?

    CERN. Geneva; Faccini, R.


    After an introduction to the controversial problem of Low Energy Nuclear Reactions (LENR) catalyzed by neutrons on metallic hydride surfaces we present the results of an experiment, made in collaboration with ENEA Labs in Frascati, to search neutrons from plasma discharges in electrolytic cells. The negative outcome of our experiment goes in the direction of ruling out those theoretical models expecting LENR to occur in condensed matter systems under specific conditions. Our criticism on the theoretical foundations of such models will also be presented.

  14. Non-IgE mediated mast cell activation

    Yu, Yingxin; Blokhuis, Bart R; Garssen, Johan; Redegeld, Frank A


    Mast cells are crucial effector cells in allergic reactions, where IgE is the best known mechanism to trigger their degranulation and release of a vast array of allergic mediators. However, IgE is not the only component to stimulate these cells to degranulate, while mast cell activation can also res

  15. Biochemistry and pathology of radical-mediated protein oxidation

    Dean, R T; Fu, S; Stocker, R


    Radical-mediated damage to proteins may be initiated by electron leakage, metal-ion-dependent reactions and autoxidation of lipids and sugars. The consequent protein oxidation is O2-dependent, and involves several propagating radicals, notably alkoxyl radicals. Its products include several catego...

  16. Fc-mediated immune precipitation. III. Visualization by electron microscopy

    Møller, NPH; Christiansen, Gunna


    Fc-mediated interactions between immune complexes are of major importance for the precipitin reaction. In the present study these interactions were investigated by means of electron microscopy. Keyhole limpet haemocyanin (KLH) was adsorbed to a thin glow charged carbon supporting film and reacted...

  17. Non-IgE mediated mast cell activation

    Yu, Yingxin; Blokhuis, Bart R; Garssen, Johan; Redegeld, Frank A


    Mast cells are crucial effector cells in allergic reactions, where IgE is the best known mechanism to trigger their degranulation and release of a vast array of allergic mediators. However, IgE is not the only component to stimulate these cells to degranulate, while mast cell activation can also res

  18. Organic chemistry: Reactions triggered electrically

    Xiang, Limin; Tao, N. J.


    Single-molecule experiments have revealed that chemical reactions can be controlled using electric fields -- and that the reaction rate is sensitive to both the direction and the strength of the applied field. See Letter p.88

  19. Theoretical Studies of Reaction Surfaces


    Similar levels of agreement are being found in studies of water clusters12 , the Menshutkin reaction 13 (ion separation reaction ), a prototypical SN2 ...of both reactants and products. These analyses reveal that Bery pseudorotation occurs repeatedly during the side attack, whereas the SN2 reaction H...31 Aug 97 4. TITLE AND SUBTITLE 5. FUNDING NUMBERS AASERT93 THEORETICAL STUDIES OF REACTION SURFACES F49620-93-1-0556 3484/XS 6. AUTHOR(S) 61103D DR

  20. [The psychoimmunological network og panic disorders, agoraphobia and allergic reactions].

    Schmidt-Traub, S


    While treating panic and agoraphobia patients with behaviour therapy, a high frequency of allergic reaction of the IgE-mediated type I was observed. Panic disorder, agoraphobia, allergic disorder, and vasomotor reactions are briefly discussed in the framework of psycho-endocrino-immunological research. A pilot study had shown a high correlation between panic disorder with and without agoraphobia and allergic reaction. A controlled study was then planned to test the hypothesized psychoimmunological relationship. 100 allergic patients, 79 panic/agoraphobic patients, and 66 controls underwent psychodiagnostic and allergic screening. 70% of the anxiety patients responded to test allergens with IgE-mediated type-I immediate reactions in comparison to 28% of the control persons. Another 15% of the panic patients reacted to nickle compound with type-IV delayed skin reactions (7% of the controls). Conversely, 10% of the allergic patients suffered from panic disorder (45% had experienced panic attacks) in contrast to 2% of the controls (24% of these reported panic attacks). The relative risk for allergic patients to develop panic disorder with and without agoraphobia is obviously five times as high as for controls. With this assumption of a psychoimmunological preparedness in mind, a behavioural medical diagnostic and therapeutic concept seems more adequate in coping both with panic/agoraphobia and allergic disorder.