Bibliographies thématiques / Secretina

Littérature scientifique sur le sujet « Secretina »

Auteur : Grafiati
Publié le 11 mars 2023

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Articles de revues sur le sujet "Secretina"

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Park, Hyung Seo, Hyeok Yil Kwon, Yun Lyul Lee, William Y. Chey et Hyoung Jin Park. « Role of GRPergic neurons in secretin-evoked exocrine secretion in isolated rat pancreas ». American Journal of Physiology-Gastrointestinal and Liver Physiology 278, no 4 (1 avril 2000) : G557—G562. http://dx.doi.org/10.1152/ajpgi.2000.278.4.g557.

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Effects of intrapancreatic gastrin-releasing peptide (GRP)-containing neurons on secretin-induced pancreatic secretion were investigated in the totally isolated perfused rat pancreas. Electrical field stimulation (EFS) increased secretin (12 pM)-induced pancreatic secretions of fluid and amylase. EFS induced a twofold increase in GRP concentration in portal effluent, which was completely inhibited by tetrodotoxin but not modified by atropine. An anti-GRP antiserum inhibited the EFS-enhanced secretin-induced secretions of fluid and amylase by 12 and 43%, respectively, whereas a simultaneous infusion of the antiserum and atropine completely abolished them. Exogenous GRP dose-dependently increased the secretin-induced pancreatic secretion with an additive effect on fluid secretion and a potentiating effect on amylase secretion, which was not affected by atropine. In conclusion, excitation by EFS of GRPergic neurons in the isolated rat pancreas results in the release of GRP, which exerts an additive effect on fluid secretion and a potentiating effect on amylase secretion stimulated by secretin. The release and action of GRP in the rat pancreas are independent of cholinergic tone.
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Solomon, Travis E., John H. Walsh, Louis Bussjaeger, Yumei Zong, James W. Hamilton, F. J. Ho, Terry D. Lee et Joseph R. Reeve. « COOH-terminally extended secretins are potent stimulants of pancreatic secretion ». American Journal of Physiology-Gastrointestinal and Liver Physiology 276, no 4 (1 avril 1999) : G808—G816. http://dx.doi.org/10.1152/ajpgi.1999.276.4.g808.

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Posttranslational processing of preprosecretin generates several COOH-terminally extended forms of secretin and α-carboxyl amidated secretin. We used synthetic canine secretin analogs with COOH-terminal -amide, -Gly, or -Gly-Lys-Arg to examine the effects of COOH-terminal extensions of secretin on bioactivity and detection in RIA. Synthetic products were purified by reverse-phase and ion-exchange HPLC and characterized by reverse-phase isocratic HPLC and amino acid, sequence, and mass spectral analyses. Secretin and secretin-Gly were noted to coelute during reverse-phase HPLC. In RIA using eight different antisera raised against amidated secretin, COOH-terminally extended secretins had little or no cross-reactivity. Bioactivity was assessed by measuring pancreatic responses in anesthetized rats. Amidated canine and porcine secretins were equipotent. Secretin-Gly and secretin-Gly-Lys-Arg had potencies of 81 ± 9% ( P > 0.05) and 176 ± 13% ( P < 0.01), respectively, compared with amidated secretin, and the response to secretin-Gly-Lys-Arg lasted significantly longer. These data demonstrate that 1) amidated secretin and secretin-Gly are not separable under some chromatographic conditions, 2) current RIA may not detect bioactive COOH-terminally extended forms of secretin in tissue extracts or blood, and 3) the secretin receptor mediating stimulation of pancreatic secretion recognizes both amidated and COOH-terminally extended secretins.
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Possot, Odile M., Guillaume Vignon, Natalia Bomchil, Frank Ebel et Anthony P. Pugsley. « Multiple Interactions between Pullulanase Secreton Components Involved in Stabilization and Cytoplasmic Membrane Association of PulE ». Journal of Bacteriology 182, no 8 (15 avril 2000) : 2142–52. http://dx.doi.org/10.1128/jb.182.8.2142-2152.2000.

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ABSTRACT We report attempts to analyze interactions between components of the pullulanase (Pul) secreton (type II secretion machinery) fromKlebsiella oxytoca encoded by a multiple-copy-number plasmid in Escherichia coli. Three of the 15 Pul proteins (B, H, and N) were found to be dispensable for pullulanase secretion. The following evidence leads us to propose that PulE, PulL, and PulM form a subcomplex with which PulC and PulG interact. The integral cytoplasmic membrane protein PulL prevented proteolysis and/or aggregation of PulE and mediated its association with the cytoplasmic membrane. The cytoplasmic, N-terminal domain of PulL interacted directly with PulE, and both PulC and PulM were required to prevent proteolysis of PulL. PulM and PulL could be cross-linked as a heterodimer whose formation in a strain producing the secreton required PulG. However, PulL and PulM produced alone could also be cross-linked in a 52-kDa complex, indicating that the secreton exerts subtle effects on the interaction between PulE and PulL. Antibodies against PulM coimmunoprecipitated PulL, PulC, and PulE from detergent-solubilized cell extracts, confirming the existence of a complex containing these four proteins. Overproduction of PulG, which blocks secretion, drastically reduced the cellular levels of PulC, PulE, PulL, and PulM as well as PulD (secretin), which probably interacts with PulC. The Pul secreton components E, F, G, I, J, K, L, and M could all be replaced by the corresponding components of the Out secretons of Erwinia chrysanthemi and Erwinia carotovora, showing that they do not play a role in secretory protein recognition and secretion specificity.
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Villanger, O., T. Veel et M. G. Raeder. « Secretin causes H+ secretion from intrahepatic bile ductules by vacuolar-type H(+)-ATPase ». American Journal of Physiology-Gastrointestinal and Liver Physiology 265, no 4 (1 octobre 1993) : G719—G724. http://dx.doi.org/10.1152/ajpgi.1993.265.4.g719.

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Intrahepatic bile duct epithelial cells contribute to bile formation by hormone-dependently secreting HCO3- to bile and H+ to periductular fluid. The present study was undertaken to determine whether the secretin-induced H+ secretion is due to activation of a H(+)-ATPase or Na(+)-H+ exchange. H+ secretion was estimated from the rate of intracellular pH (pHi) recovery after acid loading (24 mM NH4Cl) of microdissected bile ductules from pig liver mounted in a flow-through chamber on the stage of a microscope. pHi was measured from an estimated average of 10-15 epithelial cells using the fluorescent pHi indicator 2',7'-bis(carboxyethyl)-5,6-carboxyfluorescein and dual-wavelength excitation of fluorescence. The ducts were superfused with HCO3(-)-free N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid buffers. We found that secretin induced net H+ secretion of 4.53 +/- 0.7 mumol.ml cell volume-1 x min-1. This H+ secretion was blocked by 10(-6) M bafilomycin A1 but was unaffected by Na+ substitution with choline in the superfusion buffer. The experiments also showed that bafilomycin A1 did not block Na(+)-H+ exchange. The secretin-induced H+ secretion is probably caused by a vacuolar-type H(+)-ATPase and may constitute an important element of the cellular mechanisms causing secretin-dependent ductular HCO3- secretion into bile
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Frank, Steven A. « Microbial secretor–cheater dynamics ». Philosophical Transactions of the Royal Society B : Biological Sciences 365, no 1552 (27 août 2010) : 2515–22. http://dx.doi.org/10.1098/rstb.2010.0003.

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Microbial secretions manipulate the environment and communicate information to neighbours. The secretions of an individual microbe typically act externally and benefit all members of the local group. Secreting imposes a cost in terms of growth, so that cheaters that do not secrete gain by sharing the benefits without paying the costs. Cheaters have been observed in several experimental and natural settings. Given that cheaters grow faster than secretors when in direct competition, what maintains the widely observed patterns of secretion? Recent theory has emphasized the genetic structure of populations, in which secretors tend to associate spatially with other secretors, reducing direct competition and allowing highly secreting groups to share mutual benefits. Such kin selection can be a powerful force favouring cooperative traits. Here, I argue that, although kin selection is a factor, the combination of mutation and demographic processes dominate in determining the relative fitness of secretors versus cheaters when measured over the full cycle of microbial life history. Key demographic factors include the local density of microbes at which secretion significantly alters the environment, the extent to which secretion enhances microbial growth and maximum local density, and the ways in which secretion alters colony survival and dispersal.
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Blocker, Ariel, Pierre Gounon, Eric Larquet, Kirsten Niebuhr, Véronique Cabiaux, Claude Parsot et Philippe Sansonetti. « The Tripartite Type III Secreton of Shigella flexneri Inserts Ipab and Ipac into Host Membranes ». Journal of Cell Biology 147, no 3 (1 novembre 1999) : 683–93. http://dx.doi.org/10.1083/jcb.147.3.683.

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Bacterial type III secretion systems serve to translocate proteins into eukaryotic cells, requiring a secreton and a translocator for proteins to pass the bacterial and host membranes. We used the contact hemolytic activity of Shigella flexneri to investigate its putative translocator. Hemolysis was caused by formation of a 25-Å pore within the red blood cell (RBC) membrane. Of the five proteins secreted by Shigella upon activation of its type III secretion system, only the hydrophobic IpaB and IpaC were tightly associated with RBC membranes isolated after hemolysis. Ipa protein secretion and hemolysis were kinetically coupled processes. However, Ipa protein secretion in the immediate vicinity of RBCs was not sufficient to cause hemolysis in the absence of centrifugation. Centrifugation reduced the distance between bacterial and RBC membranes beyond a critical threshold. Electron microscopy analysis indicated that secretons were constitutively assembled at 37°C before any host contact. They were composed of three parts: (a) an external needle, (b) a neck domain, and (c) a large proximal bulb. Secreton morphology did not change upon activation of secretion. In mutants of some genes encoding the secretion machinery the organelle was absent, whereas ipaB and ipaC mutants displayed normal secretons.
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Seo, Jin, Anja Brencic et Andrew J. Darwin. « Analysis of Secretin-Induced Stress in Pseudomonas aeruginosa Suggests Prevention Rather than Response and Identifies a Novel Protein Involved in Secretin Function ». Journal of Bacteriology 191, no 3 (21 novembre 2008) : 898–908. http://dx.doi.org/10.1128/jb.01443-08.

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ABSTRACT Secretins are bacterial outer membrane proteins that are important for protein export. However, they can also mislocalize and cause stress to the bacterial cell, which is dealt with by the well-conserved phage shock protein (Psp) system in a highly specific manner. Nevertheless, some bacteria have secretins but no Psp system. A notable example is Pseudomonas aeruginosa, a prolific protein secretor with the potential to produce seven different secretins. We were interested in investigating how P. aeruginosa might deal with the potential for secretin-induced stress without a Psp system. Microarray analysis revealed the absence of any transcriptional response to XcpQ secretin overproduction. However, transposon insertions in either rpoN, truB, PA4068, PA4069, or PA0943 rendered P. aeruginosa hypersensitive to XcpQ production. The PA0943 gene was studied further and found to encode a soluble periplasmic protein important for XcpQ localization to the outer membrane. Consistent with this, a PA0943 null mutation reduced the levels of type 2 secretion-dependent proteins in the culture supernatant. Therefore, this work has identified a novel protein required for normal secretin function in P. aeruginosa. Taken together, all of our data suggest that P. aeruginosa lacks a functional equivalent of the Psp stress response system. Rather, null mutations in genes such as PA0943 may cause increased secretin-induced stress to which P. aeruginosa cannot respond. Providing the PA0943 mutant with the ability to respond, in the form of critical Psp proteins from another species, alleviated its secretin sensitivity.
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Pugsley, Anthony P., Nicolas Bayan et Nathalie Sauvonnet. « Disulfide Bond Formation in Secreton Component PulK Provides a Possible Explanation for the Role of DsbA in Pullulanase Secretion ». Journal of Bacteriology 183, no 4 (15 février 2001) : 1312–19. http://dx.doi.org/10.1128/jb.183.4.1312-1319.2001.

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ABSTRACT When expressed in Escherichia coli, the 15Klebsiella oxytoca pul genes that encode the so-called Pul secreton or type II secretion machinery promote pullulanase secretion and the assembly of one of the secreton components, PulG, into pili. Besides these pul genes, efficient pullulanase secretion also requires the host dsbA gene, encoding a periplasmic disulfide oxidoreductase, independently of disulfide bond formation in pullulanase itself. Two secreton components, the secretin pilot protein PulS and the minor pseudopilin PulK, were each shown to posses an intramolecular disulfide bond whose formation was catalyzed by DsbA. PulS was apparently destabilized by the absence of its disulfide bond, whereas PulK stability was not dramatically affected either by adsbA mutation or by the removal of one of its cysteines. The pullulanase secretion defect in a dsbA mutant was rectified by overproduction of PulK, indicating reduced disulfide bond formation in PulK as the major cause of the secretion defect under the conditions tested (in which PulS is probably present in considerable excess of requirements). PulG pilus formation was independent of DsbA, probably because PulK is not needed for piliation.
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Honzawa, Norikiyo, Kei Fujimoto, Masaki Kobayashi, Daisuke Kohno, Osamu Kikuchi, Hiromi Yokota-Hashimoto, Eri Wada et al. « Protein Kinase C (Pkc)-δ Mediates Arginine-Induced Glucagon Secretion in Pancreatic α-Cells ». International Journal of Molecular Sciences 23, no 7 (4 avril 2022) : 4003. http://dx.doi.org/10.3390/ijms23074003.

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The pathophysiology of type 2 diabetes involves insulin and glucagon. Protein kinase C (Pkc)-δ, a serine–threonine kinase, is ubiquitously expressed and involved in regulating cell death and proliferation. However, the role of Pkcδ in regulating glucagon secretion in pancreatic α-cells remains unclear. Therefore, this study aimed to elucidate the physiological role of Pkcδ in glucagon secretion from pancreatic α-cells. Glucagon secretions were investigated in Pkcδ-knockdown InR1G9 cells and pancreatic α-cell-specific Pkcδ-knockout (αPkcδKO) mice. Knockdown of Pkcδ in the glucagon-secreting cell line InR1G9 cells reduced glucagon secretion. The basic amino acid arginine enhances glucagon secretion via voltage-dependent calcium channels (VDCC). Furthermore, we showed that arginine increased Pkcδ phosphorylation at Thr505, which is critical for Pkcδ activation. Interestingly, the knockdown of Pkcδ in InR1G9 cells reduced arginine-induced glucagon secretion. Moreover, arginine-induced glucagon secretions were decreased in αPkcδKO mice and islets from αPkcδKO mice. Pkcδ is essential for arginine-induced glucagon secretion in pancreatic α-cells. Therefore, this study may contribute to the elucidation of the molecular mechanism of amino acid-induced glucagon secretion and the development of novel antidiabetic drugs targeting Pkcδ and glucagon.
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Park, Hyung Seo, et Hyoung Jin Park. « Effects of γ-aminobutyric acid on secretagogue-induced exocrine secretion of isolated, perfused rat pancreas ». American Journal of Physiology-Gastrointestinal and Liver Physiology 279, no 4 (1 octobre 2000) : G677—G682. http://dx.doi.org/10.1152/ajpgi.2000.279.4.g677.

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Because GABA and its related enzymes have been determined in β-cells of pancreas islets, effects of GABA on pancreatic exocrine secretion were investigated in the isolated, perfused rat pancreas. GABA, given intra-arterially at concentrations of 3, 10, 30, and 100 μM, did not exert any influence on spontaneous or secretin (12 pM)-induced pancreatic exocrine secretion. However, GABA further elevated CCK (10 pM)-, gastrin-releasing peptide (100 pM)-, or electrical field stimulation-induced pancreatic secretions of fluid and amylase dose dependently. The GABA (30 μM)-enhanced CCK-induced pancreatic secretions were completely blocked by bicuculline (10 μM), a GABAA receptor antagonist, but were not affected by saclofen (10 μM), a GABAB receptor antagonist. The enhancing effects of GABA (30 μM) on CCK-induced pancreatic secretions were not changed by tetrodotoxin (1 μM) but were partially reduced by cyclo-(7-aminoheptanonyl-Phe-d-Trp-Lys-Thr[BZL]) (10 nM), a somatostatin antagonist. In conclusion, GABA enhances pancreatic exocrine secretion induced by secretagogues, which predominantly induce enzyme secretion, via GABAA receptors in the rat pancreas. The enhancing effect of GABA is partially mediated by inhibition of islet somatostatin release.
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Thèses sur le sujet "Secretina"

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Gu, Shuang. « Secretin interactions in the type II secretion system ». Thesis, Queen Mary, University of London, 2012. http://qmro.qmul.ac.uk/xmlui/handle/123456789/2482.

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The type II secretion system (T2SS) is the major terminal branch of the general secretory pathway. It is composed of 12-15 proteins, most in multiple copies, and spans the inner and outer membranes of Gram-negative bacteria. The T2SS secretin subunits form a large dodecameric torus-like structure in the outer membrane. The secretin is the only essential component in the outer membrane and secreted proteins and virulence factors pass through the pore in the toroidal secretin dodecamer and out into the environment. The interaction between the secretin and its partners plays a key role in regulation of the T2SS. The interaction between the so-called homology region of the innermembrane protein GspC (GspC-HR) and secretin provides the structural and functional integrity of the secretion machinery across the two cell membranes. The interaction between secretin and its pilotin translocates the secretin subunits to the outer membrane. In this Thesis, the interactions between secretin and its partners are studied at molecular level. The GspC-HR structure is solved using NMR spectroscopy. Its interaction with secretin (GspD) is elucidated using several biochemical and biophysical approaches and a model of the complex is proposed. Also, the interaction between secretin (GspD) and pilotin (GspS) is further charicterisied. An 18 residues secretin sequence is identified as responsible for interacting with pilotin. Upon binding to the pilotin, the unstructured secretin forms a helical structure.
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Lau, Kwan-wa. « Cloning and characterization of the first amphibian secretins and secretin receptor functional implication of secretin with orexin in amphibians / ». Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B44143655.

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Woods, Birgitta A. « The effects of epinephrine, AVP, norepinephrine, and acetylcholine on lung liquid production in in vitro preparations of lungs from fetal guinea pigs (Cavia porcellus) ». Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/29821.

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This study examined the effects of epinephrine, norepinephrine, AVP and ACh on fluid movement by the lungs of the late-term guinea pig fetus. Catecholamines and AVP are secreted in high amounts by the fetus during delivery, and could be important with respect to fetal lung fluid removal; this event is vital at the time of birth. The lungs were supported in vitro for a duration of three hours, and production rates were measured using a dye-dilution technique. The average resting production rate in terms of ml/kg‧h declined with gestational age (54-67 days gestation; n=171). There was a lesser decline in the average resting production rate in terms of ml/h. The average production rate of untreated preparations in the first hour was 1.60 ± 0.26 ml/kg body weight per hour, and rates did not change significantly during the remaining two hours of experimentation (n=30). This rate is comparable to those reported from chronically catheterized fetal sheep. Treatment was administered during the second hour of experimentation, following an ABA design. Lungs (n=36) were transferred to fresh Krebs-Henseleit saline containing one of the following concentrations of epinephrine: (a) 10‾⁵ M; (b) 10‾⁶ M; (c) 10‾⁷ M; (d) 5 x 10‾⁸ M; (e) 10‾⁸ M; and (f) 10‾⁹ M. With the exception of the top dose, epinephrine treatment caused an immediate reduction in fluid secretion, or fluid reabsorption. Sodium followed the movement of water in all cases. The effect of epinephrine at 10‾⁷ M was maximal, and the threshold dose for epinephrine was calculated at 1.78 x 10‾¹¹ M. Phentolamine and propranolol had no effect in control preparations. However, phentolamine completely blocked the effect of epinephrine, whereas propranolol was ineffective. Isoproterenol had no effect on pulmonary fluid production. Alpha-adrenergic receptors apparently mediate the effect of epinephrine on pulmonary fluid movement in the fetal guinea pig lung. This conclusion is different from that obtained in fetal sheep, in which beta-adrenergic receptors are utilized. A possible synergism between epinephrine and AVP was examined. Lungs (n=12) were transferred to fresh Krebs-Henseleit saline containing either (a) 0.6 mU/ml AVP, or b) 0.6 mU/ml AVP combined with epinephrine at 10‾⁷ M. Treatment with AVP caused a slow, prolonged reduction in fluid production. Treatment with AVP together with epinephrine did not demonstrate synergism. The effect of norepinephrine (NE) was examined. Lungs (n=36) were transferred to fresh Krebs-Henseleit saline containing one of the following concentrations of NE: (a) 1.24 x 10‾⁵ M; (b) 1.24 x 10‾⁶ M; (c) 1.24 x 10‾⁷ M; (d) 5.24 x 10‾⁸ M; (e) 1.24 x 10‾⁸ M; and (f) 1.24 x 10‾⁹ M. In all preparations, treatment with NE resulted in an immediate reduction in fluid production, and reabsorptions were observed at the higher doses. Sodium followed the movement of water in every case. The threshold dose was calculated at 3.16 x 10‾¹⁰ M. Phentolamine blocked the effect of NE, reinforcing the importance of pulmonary alpha-adrenergic receptors in the fetal guinea pig. There was no relationship between age and degree of response with treatment of either epinephrine or NE, but fetuses under 78.0 g did not respond to NE. The effect of ACh was examined. Lungs (n=24) were transferred to fresh Krebs-Henseleit saline containing one of the following concentrations of ACh: (a) 10‾⁴ M; (b) 10‾⁵ M; (c) 10‾⁶ M; and (d) 10‾⁸ M. At the three top doses, immediate and powerful reabsorptions of pulmonary fluid were observed in older fetuses (60 days gestation and above); significant falls were observed in the younger fetuses. This result was unexpected, as it was hypothesized that ACh would stimulate fluid production. The threshold dose for ACh was between 10‾⁶ M and 10‾⁸ M. Phentolamine blocked the effect of ACh. This result suggested that reabsorption is a result of an indirect effect of ACh acting through pulmonary alpha receptors. The results in this study show that epinephrine, NE, AVP and ACh are all important promoters of fetal pulmonary fluid removal in the fetal guinea pig. Pulmonary alpha-adrenergic receptors mediate the effects of epinephrine, NE and ACh (indirectly). The conclusions drawn from this study emphasize the importance of species' comparison in fetal research. LIST OF ABBREVIATIONS AVP Arginine Vasopressin NE Norepinephrine DOPA dihydroxyphenylalanine PNMT Phenylethanolamine n-methyltransferase ACh Acetylcholine
Science, Faculty of
Zoology, Department of
Graduate
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Lau, Kwan-wa, et 劉君華. « Cloning and characterization of the first amphibian secretins and secretin receptor : functional implication ofsecretin with orexin in amphibians ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B44143655.

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Robertson, Katherine. « The role of the growth hormone/IGF-I system on islet cell growth and insulin action / ». Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=103288.

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The study of diabetes mellitus is vital in this day and age because its incidence is increasing at an alarming rate. Diabetes results in the loss of function of beta-cells within the pancreas. Insulin resistance contributes to diabetes but the human body can compensate in various ways such as increasing the islet cell mass, glucose disposal and insulin secretion, in order to prevent the onset of diabetes. Growth hormone (GH) and insulin-like growth factor-I (IGF-I) are two integral hormones important in both glucose homeostasis and islet cell growth. Early studies using cultured islet cells have demonstrated positive regulation of beta-cell growth by both GH and IGF-I. To evaluate their relevance on normal beta-cell growth, compensatory growth, as well as in insulin responsiveness, we have used two mouse models that represent opposite manipulations of the GH/IGF-I axis. Specifically, the growth hormone receptor gene deficient (GHR-/-) and the IGF-I overexpression (MT-IGF) mice, to help understand the role of glucose homeostasis and islet cell growth in the GH/IGF-I axis. GH is essential for somatic growth and development as well as maintaining metabolic homeostasis. It is known that GH stimulates normal islet cell growth. Moreover, GH may also participate in islet cell overgrowth and compensate for insulin resistance induced by obesity. To determine whether the islet cell overgrowth is dependent on GH signaling, we studied the response of GHR-/- mice to high-fat diet (HFD)-induced obesity. We also studied the insulin responsiveness in GHR-/- mice. On the other hand, IGF-I promotes embryonic development, postnatal growth and the maturation of various organ systems. The notion that IGF-I stimulates islet cell growth has been challenged in recent years by results from IGF-I and receptor gene targeted models. We have characterized MT-IGF mice which overexpress the IGF-I gene.
The results of our studies indicate that (1) GH is essential for normal islet cell growth, but not required for compensatory overgrowth of the islets in response to obesity, (2) GHR gene deficiency caused delayed insulin responsiveness in skeletal muscle; in contrast to elevated insulin sensitivity in the liver; (3) although overexpression does not stimulate islet cell growth, a chronic IGF-I elevation caused significant hypoglycemia, hypoinsulinemia, and improved glucose tolerance, (4) finally IGF-I overexpression mice are resistant to experimental diabetes.
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Scott, Gary Terri. « The role of micro-organisms in the production of semiochemicals in the interdigital secretion of the bontebok, Damaliscus pygargus pygargus ». Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/53774.

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Thesis (MSc)--Stellenbosch University, 2004.
ENGLISH ABSTRACT: Bontebok, Damaliscus pygargus pygargus, formerly classified as D. dorcas dorcas, are territorial animals with interdigital glands between the toes of the forelegs. Males regularly defecate on dung heaps, on which they often lie, to communicate with other members of their species. They also communicate by means of visual displays, scent marking and occasionally with scraping or pawing of dung heaps. It is assumed that scent marking with the interdigital secretion serves to define territories frequented by these antelope. These glands secrete a complex mixture of volatile and non-volatile compounds and the volatile compounds in the secretion serve as a chemical signal for other bontebok. It has been suggested that the interdigital secretion is not produced in its final composition by the interdigital gland alone, but that microbial activity is responsible for many of the compounds present in the secretion. In general, many compounds can be attributed to the by-products of microbial hydrolysis of triglycerides, a common characteristic of sebum. It is well documented that micro-organisms inhabit the deep recesses of sebaceous glands and the presence of micro-organisms has been found to be consistent in all antelope exocrine glandular areas. This study involved the chemical characterisation of the volatile metabolites produced in vitro by micro-organisms from the interdigital cavity of the bontebok. Various comparative studies were made, one of which was comparison of the metabolites produced by the individual microbial species as well as the total community of bacteria incubated in different media. A comparison of the compounds identified in the interdigital secretion and the metabolites produced by the micro-organisms in the different media was also made. The volatile metabolite extracts of the individual bacterial species and of the total community were chemically characterised by low-resolution gas chromatography-mass spectroscopy. Classes of compounds identified from the volatile metabolite extracts include: • Acids - Aliphatic (saturated and unsaturated) • Alcohols - Aliphatic (saturated and unsaturated) • Aldehydes - Aliphatic (saturated and unsaturated) • Aromatic compounds • Ketones - Aliphatic (saturated and unsaturated) • Pyrazines • Dimethyldisulphide • Squalene and cholesterol Several qualitative differences were found between the compounds identified in the volatile metabolite extracts of the micro-organisms when incubated in tryptic soy broth (TSB) and minimal salt medium (MSM). In particular, when the microbes were incubated in TSB medium a number of pyrazines were found that were not present when utilising MSM as a medium. Additional qualitative differences were found between the compounds identified in the metabolite extracts of the individual bacterial species and the total community of bacteria, when incubated in both TSB and MSM media. A comparison of the interdigital secretion and the metabolite extracts of the microbial communities incubated in TSB and MSM revealed that many compounds produced in MSM corresponded to the compounds identified in the interdigital secretion. These corresponding compounds were found to be saturated and unsaturated acids, aldehydes and squalene. Furthermore, there was only one corresponding compound in the case of TSB as medium.
AFRIKAANSE OPSOMMING: Die bontebok, Damaliscus pygargus pygargus, voorheen geklassifiseer as D. dorcas dorcas, is 'n territoriale dier met interdigitale kliere tussen die kloutjies van die voorpote. Ramme ontlas gereeld op mishope, waarop hulle dikwels lê, om met ander lede van die spesie te kommunikeer. Hulle kommunikeer ook deur middel van visuele seine, reukmerking en soms deur mishope met die voorpote te kap of te skraap. Reukmerking met die interdigitale afskeiding dien klaarblyklik om gebiede wat deur hierdie diere bewoon word, af te baken. Die interdigitale kliere skei 'n komplekse mengsel van vlugtige en nie-vlugtige verbindings af en die vlugtige verbindings dien as chemiese sein vir ander bontebokke. Die vermoede bestaan dat die interdigitale klier nie alleen verantwoordelik is vir die finale samestelling van die interdigitale afskeiding nie, maar dat mikrobiese aktiwiteit bydra tot die produksie van baie van die verbindings wat in die afskeiding aanwesig is. Sekere verbindings kan in die algemeen toegeskryf word aan die vorming van die neweprodukte van mikrobiese hidrolise van trigliseriede, 'n algemene eienskap van sebum. Dit is bekend dat die diep holtes van vetkliere 'n goeie teelaarde is vir mikroorganismes en daar is gevind dat mikroorganismes feitlik deurgaans voorkom in alle anteloop eksokriene klierareas. Hierdie studie behels die chemiese karakterisering van die vlugtige metaboliete wat in vitro deur mikroorganismes van die interdigitale klierholte van die bontebok geproduseer word. Verskeie vergelykende studies is uitgevoer waarvan een die vergelyking was van die metaboliete wat deur die individuele mikrobiese spesies sowel as die totale gemeenskap van bakterieë geproduseer word tydens inkubasie in verskillende media. Vergelyking van die verbindings wat in die interdigitale afskeiding geïdentifiseer is met die metaboliete wat in verskillende media geproduseer is, het ook deel van die studie uitgemaak. Die vlugtige metaboliet ekstrakte van die individuele bakteriese spesies en van die totale gemeenskap is chemies gekarakteriseer deur middel van laeresolusie gaschromatografie-massaspektrometrie. Die volgende groepe verbindings is onder andere in die vlugtige metaboliet ekstrakte geïdentifiseer: • Sure - Alifaties (versadig en onversadig) • Alkohole - Alifaties (versadig en onversadig) • Aldehiede - Alifaties (versadig en onversadig) • Aromatiese verbindings • Ketone - Alifaties (versadig en onversadig) • Pirasiene • Dimetieldisulfied • Skwaleen en cholesterol Verskeie kwalitatiewe verskille is gevind tussen die verbindings wat geïdentifiseer is in die vlugtige metaboliet ekstrakte van die mikroorganismes onderskeidelik in TSB medium en MSM geïnkubeer. Opvallend was byvoorbeeld die voorkoms van pirasiene in gevalle waar mikroorganismes in TSB medium geïnkubeer is, terwyl hierdie groep verbindings afwesig was wanneer MSM gebruik is. Onderlinge kwalitatiewe verskille is ook gevind tussen die verbindings wat geïdentifiseer is in die metaboliet ekstrakte van die individuele bakteriese spesies en die totale gemeenskap van bakterieë, wanneer in TSB medium sowel as in MSM geïnkubeer is. Vergelyking van die verbindings in die interdigitale afskeiding en in die metaboliet ekstrakte van die mikrobiese gemeenskappe, het getoon dat 'n aantal verbindings wat in MSM geproduseer is, ooreenstem met verbindings wat in die interdigitale afskeiding geïdentifiseer is. Daar is gevind dat hierdie verbindings versadigde en onversadigde sure en aldehiede en skwaleen is. Met TSB as medium was daar slegs een ooreenstemmende verbinding.
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LANGLOIS, ANNIK. « Contribution a l'etude de la regulation hormonale des secretions digestives chez le porc : effets du polypeptide pancreatique sur la secretion pancreatique exocrine et la secretion biliaire chez l'animal conscient ». Paris 7, 1989. http://www.theses.fr/1989PA077080.

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Carroll, Kathleen. « An investigation into the molecular mechanisms regulating IgE-mediated secretion in high- and low- secreting variants of the rat basophilic leukaemia cell-line ». Thesis, University of Sheffield, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298883.

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Fong, Shi-ming. « Characterization of the human secretin receptor gene / ». Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B20792906.

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Guschinskaya, Natalia. « Caractérisation moléculaire des signaux de sécrétion des protéines sécrétées par le système de sécrétion de type II de la bactérie phytopathogène Dickeya dadantii ». Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10085/document.

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Le système de sécrétion de type II (T2SS) assure le transport de protéines sous une forme repliée du périplasme dans le milieu extracellulaire. Ce système est largement exploité par les bactéries à Gram négatif pathogènes des plantes, des animaux et de l'homme où il permet la sécrétion de facteurs de virulence (des toxines et des enzymes lytiques). La bactérie phytopathogène Dickeya dadantii utilise le T2SS appelé Out, pour sécréter une douzaine de pectinases qui dégradent les parois des cellules végétales. Les protéines sécrétées par le T2SS n'ont pas de motif de sécrétion apparent et leur sécrétion implique plusieurs interactions transitoires avec les composants du système. La nature moléculaire de ces interactions n'est pas connue. Afin de capter ces interactions transitoires lors du processus de sécrétion, j'ai utilisé le pontage dirigé in vivo. Cette technique repose sur l'incorporation d'un analogue photoréactif d'un acide aminé (le para-benzoyl Lphénylalanine, pBpa) à la place des résidus soupçonnés de faire partie d'un site d'interaction. Le pontage est ensuite activé par une courte exposition des cellules aux UV ce qui permet la formation des complexes protéiques. Tout d'abord, cette technique a été utilisée pour introduire le pBpa dans plusieurs régions exposées à la surface d'une exoprotéine, PelI. Cette stratégie a permis de mettre en évidence qu'un élément structural, la boucle 3 du domaine Fn3 de PelI, est impliquée dans l'interaction avec la sécrétine OutD, le composant du T2SS situé dans la membrane externe, et avec le domaine PDZ d'OutC, un composant de la membrane interne. Ces résultats suggèrent que la boucle 3 fait partie d'un motif de sécrétion. Deux autres régions ont été identifiées au sein de PelI : le linker entre les deux domaines de PelI qui est impliqué dans l'interaction avec OutD et une région exposée du domaine catalytique qui interagit avec la protéine OutC. La même approche a été utilisée pour introduire le pBpa dans les deux composants du T2SS, OutC et OutD. Ces expériences ont suggéré que le domaine PDZ d'OutC interagit avec une autre exoprotéine, PelB. Cette étude, de façon complémentaire à d'autres approches, nous a permis de démontrer certains détails moléculaires essentiels de la sécrétion par le T2SS
The type II secretion system (T2SS) transports folded proteins from the periplasm through the outer membrane into the milieu. In many pathogenic Gram-negative bacteria, the T2SS secretes various virulence factors in host tissue and is directly involved in pathogenesis. The phytopathogen Dickeya dadantii secretes a dozen of pectinases through a T2SS named Out. The secreted proteins are lacking an obvious common signal and secretion is thought to involve multiple transient interactions of folded exoproteins with several T2SS components. Molecular nature of these interactions remains unknown. To address this question we used an in vivo sitespecific photo-crosslinking approach to capture such transient interactions within the functional T2SS of D. dadantii. In this technique, the photo-crosslinker para-benzoyl-L-phenylalanine, pBpa, is introduced in vivo in place of a residue of interest and UV-irradiation of living cells provokes the formation of complexes between the protein of interest and its partners. First, in a systematic approach, pBpa was introduced at several surface-exposed sites of the secreted protein PelI. This strategy permitted us to identify that one structural element, loop 3 of Fn3 domain in PelI, interacts both with the secretin, the outer membrane T2SS component, and with the PDZ domain of OutC, an inner membrane T2SS component. These results suggest that this loop 3 is a part of the secretion motif. The same approach permitted us to identify two other regions of PelI interacting with the T2SS: a linker situated between the two domains of PelI, which interacts with OutD, and an exposed region of the catalytic domain of PelI interacting with OutC. In another approach, pBpa was introduced into the T2SS components, OutC and OutD. These experiments suggested that the PDZ domain of OutC interacts with the secreted protein PelB. This study, in complement with other approaches, allowed us to uncover some important molecular features of the protein secretion by the T2SS
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Livres sur le sujet "Secretina"

1

Salehi, Sebastian Albert. Insulin secretion : Modulation of islet acid glucan-1,4-gas-glucosidase activity by selective inhibitors, Ca2+ and nitric oxide. Lund [Sweden] : Department of Pharmacology, Lund University, 1995.

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Carlo, Braga Pier, et Allegra Luigi, dir. Methods in bronchial mucology. New York : Raven Press, 1988.

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C, Scarpignato, et Bianchi Porro Gabriele, dir. Clinical investigation of gastric function. Basel : Karger, 1990.

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Economou, Anastassios, dir. Protein Secretion. Totowa, NJ : Humana Press, 2010. http://dx.doi.org/10.1007/978-1-60327-412-8.

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Pompa, Andrea, et Francesca De Marchis, dir. Unconventional Protein Secretion. New York, NY : Springer New York, 2016. http://dx.doi.org/10.1007/978-1-4939-3804-9.

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Jiang, Liwen, dir. Plant Protein Secretion. New York, NY : Springer New York, 2017. http://dx.doi.org/10.1007/978-1-4939-7262-3.

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Jena, Bhanu P. NanoCellBiology of Secretion. Boston, MA : Springer US, 2012. http://dx.doi.org/10.1007/978-1-4614-2438-3.

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Velibor, Krsmanović, et Whitfield James F, dir. Malignant cell secretion. Boca Raton : CRC Press, 1990.

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Antolín, Mario Pérez. Semántica secreta. Valladolid : Fundación Jorge Guillén, 2007.

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Mariz, Ana Lucia. Alma secreta. São Paulo, SP, Brasil : Terra Virgem Editora, 2006.

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Chapitres de livres sur le sujet "Secretina"

1

Cordeaux, Cara. « Secretin ». Dans Encyclopedia of Autism Spectrum Disorders, 2691–92. New York, NY : Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4419-1698-3_1262.

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La Rosa, Stefano. « Secretin ». Dans Endocrine Pathology, 728–30. Cham : Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-62345-6_5199.

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Cordeaux, Cara. « Secretin ». Dans Encyclopedia of Autism Spectrum Disorders, 4114–15. Cham : Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-319-91280-6_1262.

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Miller, Laurence J. « Secretin Receptor ». Dans Encyclopedia of Signaling Molecules, 4860–65. Cham : Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-67199-4_101788.

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Miller, Laurence J. « Secretin Receptor ». Dans Encyclopedia of Signaling Molecules, 1–6. New York, NY : Springer New York, 2016. http://dx.doi.org/10.1007/978-1-4614-6438-9_101788-1.

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Dunne, M. J., et O. H. Petersen. « Ion Channels in Insulin-Secreting Cells : Their Role in Stimulus-Secretion Coupling ». Dans Epithelial Secretion of Water and Electrolytes, 277–91. Berlin, Heidelberg : Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-75033-5_20.

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Rothman, Stephen. « Secretion ». Dans Proteins Crossing Membranes, 47–50. Boca Raton : Taylor & Francis, 2019. : CRC Press, 2019. http://dx.doi.org/10.1201/9780429020810-7.

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Viotti, Corrado. « ER to Golgi-Dependent Protein Secretion : The Conventional Pathway ». Dans Unconventional Protein Secretion, 3–29. New York, NY : Springer New York, 2016. http://dx.doi.org/10.1007/978-1-4939-3804-9_1.

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Stock, Janpeter, Marius Terfrüchte et Kerstin Schipper. « A Reporter System to Study Unconventional Secretion of Proteins Avoiding N-Glycosylation in Ustilago maydis ». Dans Unconventional Protein Secretion, 149–60. New York, NY : Springer New York, 2016. http://dx.doi.org/10.1007/978-1-4939-3804-9_10.

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Dias, Marcos Vinicios Salles, Vilma Regina Martins et Glaucia Noeli Maroso Hajj. « Stress-Inducible Protein 1 (STI1) : Extracellular Vesicle Analysis and Quantification ». Dans Unconventional Protein Secretion, 161–74. New York, NY : Springer New York, 2016. http://dx.doi.org/10.1007/978-1-4939-3804-9_11.

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Actes de conférences sur le sujet "Secretina"

1

Tsomartova, Dibakhan, Nataliya Yaglova, Sergey Obernikhin, Svetlana Nazimova et Valentin Vasilyevich Yaglov. « ALTERED CYTOPHYSIOLOGY OF EPINEPHRINE-PRODUCING CELLS IN RATS AFTER CHRONIC EXPOSURE TO LOW DOSES OF DDT ». Dans NEW TECHNOLOGIES IN MEDICINE, BIOLOGY, PHARMACOLOGY AND ECOLOGY. Institute of information technology, 2021. http://dx.doi.org/10.47501/978-5-6044060-1-4.12.

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Chronic low-dose exposure to dichlorodiphenyltrichloroethane does not diminish epinephrine production since epinephrine-secreting adrenal cells significantly intensify mitochondrial ac-tivity to restore epinephrine secretion.
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Moffat, E. H., R. H. Furlong, A. L. Bloom et J. C. Giddings. « A MURINE MODEL FOR FACTOR VIII ANTIBODY ANTI-IDIOTYPE REAGENTS ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644030.

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The regulation of factor VIII antibody (FVIIIAb) production in haemophilic and non-haemophilic patients may be effected by anti-idiotype (Aid) antibodies which specifically react with FVIIIAb. Aid antibodies (reagents) were prepared from rabbits immunised with murine monoclonal FVIIIAb. Immuno fluorescent microscopy and cell culture studies were performed using murine hybridoma cells which secreted the FVIIIAbs.Immuno fluorescence studies examined the ability of the Aid reagents to bind to acetone fixed FVIIIAb secreting hybridoma cells. Positive surface membrane and intra-cytoplasmic staining patterns were seen with the Aid reagent when incubated with the corresponding murine hybridoma cell line. This reaction was blocked subsequent to the addition of the corresponding monoclonal FVIIIAb but was preserved when unrelated monoclonal FVIIIAb was incubated with the hybridoma cells. No fluorescence was observed when Aid reagent was incubated with unrelated FVIIIAb secreting hybridoma cultures.Following the addition of Aid reagent to FVIIIAb secreting hybridoma cultures and incubation for 19 hours, the resultant hybridoma supernatants were examined for FVIIIAb content using an immunoradiometric technique. The Aid reagent failed to inhibit FVIIIAb secretion by hybridoma cells. Thus, although Aid reagents were capable of binding to fixed FVIIIAb secreting cells, they failed to inhibit FVIIIAb secretion from hybridoma cultures. The conjugation of Aid reagent with immunotoxin may however have cytotoxic potential. The murine model provides a method for the study of Aid regulation of FVIIIAb production in haemophilia.
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Koike, Kazuo, et Holm Holmsen. « REQUIREMENT FOR THROMBIN RECEPTOR OCCUPANY DURING PLATELET SECRETION UNDER AGGREGATING CONDITIONS ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644469.

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We have previously showed that hirudin abruptly arrests thrombin-induced secretion of acid hydrolase at any stage of its progress, whereas it only affects dense granule secretion only at its initial stages; these results have been interpreted to show that acid hydrolase secretion requires sustained while dense granule secreion ony requires a brief receptor occupancy (Holmsen et al. JBC 256(1981)9393). The requirement for receptor occupancy in thrombin-induced α-granule secretion and secretion during aggregation have been studied. Increasing concentrations of thrombin were added to gel-fitered platelets containing a constant, high concentration of hirudin. Dense granule secretion was initiated at lower thrombin concentration than those required for α-granule secretion and aggregation; acid hydrolase secretion required higher concentrations. A 14-fold exess of hirudin produced abrupt stop of dense granule secretion and α-granule secretion when added to platelets shortly after thrombin; it had no affect after these secretory process had reached 30% of their maximal values. Acid hydrolase secretion was, however, abruptly stopped by hirudin at any stage. When the platelets were allowed to aggregate, all three secretory processes increased their rates and could now be abruptly stopped by hirudin at any stage. Aggregation (optical) occurred slower than dense granule andoαgranule secretion, and was reversed by hirudin when added before it had reached 30% of its maximum. It is concluded thatαgranule secretion, like dense granule secretion, only requires a short receptor occupancy to be completed, in contrast to the requirement for sustained occupancy for hydrolase secretion.α-granule secretion might, however, require longer occupancy than dense granule secretion. It is possible that aggregation potentiates all secretory responses through close cell contact and that the abrupt inhibition by hirudin of all secretions may have been caused by its effect on the slower aggregation.
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Gomes Vieira Carvalho, Thainá, Joyce Mothé de Souza, Elisa Haddad Pessanha Rangel, Caio Gomes Muniz, Julia Maria Maia de Azevedo et Luciano Matos Chicayban. « Bronchial hygiene technique in patients with cystic fibrosis ». Dans 7th International Congress on Scientific Knowledge. Biológicas & Saúde, 2021. http://dx.doi.org/10.25242/8868113820212402.

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Cystic Fibrosis is characterized by excess pulmonary secretions that cause recurrent respiratory infections, with consequent deterioration of gas exchange. Bronchial hygiene techniques aim to mobilize secretions from the peripheral airways so that they can be eliminated by coughing or tracheal aspiration. To identify the effects of different bronchial hygiene techniques on improving lung function in patients with Cystic Fibrosis. Through a systematic review of the literature, randomized controlled trials (RCTs) published between 2007 and 2021 were selected, according to the highest score in the PEDro score. The search involved the PEDro and PubMed databases, using the following keywords: bronchial hygiene. Six ECR`s were included. One study performedthe techniques during anesthesia and observed increased resistance and reduced compliance. Regarding FEV1, 3 RCTs with hospitalized patients showed improvement in lung function, regardless of the technique used. In outpatients, there was no improvement. Regarding secretion weight, the cough machine produced more secretion than autogenous drainage, as well as a drop in saturation after the 2-min walk test, and increased FEV1. Bronchial hygiene techniques in patients with cystic fibrosis have been shown to be effective in removing mucus, with consequent improvement in lung function and aerobic fitness.
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Bowen-Pope, D. F., C. Gajdusek, J. Harlan, P. Nawroth, R. Ross, K. S. Sakariassen et D. Stern. « REGULATION OF GROWTH FACTOR PRODUCTION BY ENDOTHELIAL CELLS IN RESPONSE TO COAGULATION AND INFLAMATORY FACTORS ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1642947.

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Platelet-derived growth factor (PDGF) is a polypeptide growth factor first discovered in, and purified from, human blood platelets. As assayed by its ability to stimulate proliferation of cultured vascular smooth muscle cells, PDGF is the major mitogen in human whole blood serum. PDGF has also been reported to be chemotactic for fibroblasts, vascular smooth muscle cells, and leukocytes, and to be able to stimulate contraction of arterial smooth muscle. This, spectrum of activities suggests that PDGF could play a significant role in several vascular processes, including wound repair and the formation of atherosclerotic lesions (reviewed in Ross et al., 1986 Cell 46:155). Several cell types in addition to the platelet have now been shown to be capable of secreting PDGF-like molecules. In culture, vascular endothelial cells from many sources secrete significant levels of PDGF (DiCorleto and Bowen-Pope, 1983 PNAS 80:1919). Rates of secretion can be increased four fold and more bythe activated procoagulants thrombin (Harlan et al 1986 J. Cell Biol. 103:1129) and factor Xa (Gajdusek et al 1986 J. Cell Biol. 103:419). Thrombin stimulates secretion by the earliest times measurable (about 1.5hr) and this early response is not diminished by inhibitors of protein and RNA synthesis. Nevertheless, unlike secretion from the platelet, stimulated secretion does not represent release of sequestered active PDGF since no reservoir of active PDGF can be detected within the cells prior to stimulation. It is likely therefore that stimulation of secrtion involves the activation or unmasking of an inactive form of PDGF. The proteolytic activities of thrombin and Xa are necessary for activation of secretion but the mechanism does not seem to to involve direct proteolytic activation by thrombin of a precursor since thrombin treatment does not generate active PDGF in freeze-thawed preparations of endothelial cells. We have recently found that tumor necrosis factor alpha (TNF) and gamma interferon (IFN) can stimulate increased rates of secretion of PDGF by cultured human saphenous vein and umbilical vein endothelial cells. Stimulation by a combination of the two is more than additive. In contrast to the rapid kinetics of stimulation by thrombin and Xa, TNF and IFN do not measurably increase secretion for at lease four hrs. This delayed kinetics is paralleled by increases in mRNA encoding the two subunit chains of PDGF ("A" and "B") and it seems likely that in this case stimulation of secretion results from increased rates of mRNA and protein synthesis. Since evidence is accumulating that TNF and IFN are both present in human atherosclerotic lesions, it is possible that they help stimulate production of endothelial cell-derived mitogens, including PDGF and thus contribute to the development of the lesion.
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Yeung, Edward S., Wei Tong et Sheri Lillard. « Cell Imaging by Laser-Induced Native Fluorescence Microscopy ». Dans Laser Applications to Chemical and Environmental Analysis. Washington, D.C. : Optica Publishing Group, 1998. http://dx.doi.org/10.1364/lacea.1998.lma.2.

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The high degree of heterogeneity of the nervous and endocrine systems makes it extremely important for real-time monitoring of dynamic chemical changes at the single-cell level to gain a better understanding of the interaction of cells with their environment. Secretion mediated by exocytosis is one of the fundamental phenomena whose mechanism mimics the release of neurotransmitters at synaptic sites. Although the regulation of the secretory pathway has been studied extensively, its molecular mechanism is still not clear. It is important to develop methods that can follow real-time secretory processes with both high temporal and high spatial resolution. The native fluorescence of some proteins and neurotransmitters excited by a deep-UV laser has been shown to be a powerful probe for single-cell analysis. The advantages of direct native fluorescence detection include: (1) no chemical derivatization with fluorescent dyes is needed so no contamination or additional background will be introduced; (2) uncertainties about the efficiencies of the derivatization reaction are eliminated to ensure fast and quantitative response, without influences from slow reaction kinetics or incomplete equilibrium; and (3) the biological integrity of the cells will not be unnecessarily disturbed by having additional reagents or from exposure to artificial environments. We report the coupling of laser-induced native fluorescence detection with capillary electrophoresis (CE) to quantitatively monitor the secretion of insulin, serotonin and catecholamines from single cells. The uptake of serotonin by single living astrocytes was also recorded by native fluorescence imaging microscopy. The catecholamine (mainly epinephrine and norepinephrine) secreting adrenal chromaffin cells have been used as “model nerve terminals” to elucidate the molecular mechanism of neurotransmitter secretion at the nerve terminal. The in vitro dynamics of catecholamine release from bovine adrenal chromaffin cells was monitored with both high spatial and high temporal resolution.
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Saito, Kanako, Pascale Pignon, Maha Ayyoub et Danila Valmori. « Abstract B056 : Modulation of cytokine secretion allows CD4 T cells secreting IL-10 and IL-17 to simultaneously participate in maintaining tolerance and immunity ». Dans Abstracts : CRI-CIMT-EATI-AACR Inaugural International Cancer Immunotherapy Conference : Translating Science into Survival ; September 16-19, 2015 ; New York, NY. American Association for Cancer Research, 2016. http://dx.doi.org/10.1158/2326-6074.cricimteatiaacr15-b056.

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ROCHA, Sofia Marques, Bruna Hudson Neves PEREIRA, Emanuelle Silva OLIVEIRA, Letícia Santos JUNQUEIRA et Glenda Ribeiro OLIVEIRA. « RELEVANCE OF THE HEALTH CONDITION AND CLINICAL CHARACTERISTICS OF SPOROTRICHOSIS ». Dans SOUTHERN BRAZILIAN JOURNAL OF CHEMISTRY 2021 INTERNATIONAL VIRTUAL CONFERENCE. DR. D. SCIENTIFIC CONSULTING, 2022. http://dx.doi.org/10.48141/sbjchem.21scon.41_abstract_rocha.pdf.

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Feline sporotrichosis is a zoonosis caused by S. brasiliensis, and it presents a degree of great underreporting due to its contamination. Caused by inoculation directly into the skin, in most cases through scratches or bites by infected animals. With its first diagnosis in 1907 among naturally infected mice. The study presents information on the health of the animal, composed of 24 felines of both sexes, obtaining information through questionnaires about food along with vaccination, deworming, and ectoparasites control. In addition to depicting the types of injuries and body parts such as head, limbs, and trunk. Seeking to provide important information about animal health, along with the follow-up of a Veterinary Doctor. General care that meets the health of no animal meets all care. The disease may present some systemic symptoms such as secretions, anorexia, apathy, difficulty breathing, fever, ulcers, and abscesses. In the study, 4% of the cats had a respiratory clinical picture. Regarding the lesions, it was mostly noted that 96% of the felines had multiple lesions and 4% had single lesions in the areas of the body, being 67% of secretion with pure bloody characteristics and 33% had no secretions, with the main sites of involvement being 58% in the head region, 36% in the limbs and 6% in the trunk. Factors related to feline immunocompromise may result in more severe cases of sporotrichosis as observed in the study animals. All information obtained was evaluated using basic descriptive statistics. Relative frequency values and percentage values were assigned to the variables observed in the research.
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Romanuik, Sean F., Samantha M. Grist, Moeed Haq, Bonnie L. Gray, Naveed Gulzar et Jamie K. Scott. « The Microfluidic Trapping of Antibody-Secreting Cells ». Dans ASME 2010 8th International Conference on Nanochannels, Microchannels, and Minichannels collocated with 3rd Joint US-European Fluids Engineering Summer Meeting. ASMEDC, 2010. http://dx.doi.org/10.1115/fedsm-icnmm2010-30845.

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Therapeutic antibodies (Abs) are a rapidly growing and economically promising biotechnological research area. Therapeutic Ab production typically involves screening large numbers of Ab-secreting cells (ASCs) in order to identify those producing Abs targeting a specific antigen (Ag) with the highest affinity; a process often requiring weeks to complete. We are contributing to a multidisciplinary project focused upon the development of an immunobiosensing array ultimately intended to directly monitor the Ag-specific Ab production by thousands of ASCs on a single slide in real-time. Each ASC shall be microfluidically guided and trapped near a surface plasmon (SP) resonant nanohole array sensor so as to detect the binding of secreted Abs to Ag immobilized onto the sensor’s surface. This paper presents the initial progress of our contribution to this project: the development of polymeric microfluidic devices to guide and trap large ASC populations within arrays of single-cell traps. More specifically, this paper presents several different polymer-based microfluidic trapping devices, based upon perfusive flow-through cell traps and microwells which trap settling cells, which have been evaluated using COMSOL® simulations and tested using microsphere- and cell-based flow experiments. Our initial results are promising, and verify the functionality of our microfluidic cell trap designs.
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Takahashi, Nozomi, Hiromi Nakamura, Takuji Narumi, Michitaka Hirose et Kazuma Aoyama. « Electrical Stimulation Promotes Saliva Secretion : Proposition of Novel Interaction via Saliva Secretion ». Dans CHI '20 : CHI Conference on Human Factors in Computing Systems. New York, NY, USA : ACM, 2020. http://dx.doi.org/10.1145/3334480.3382952.

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Rapports d'organisations sur le sujet "Secretina"

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Rose, Sam, Peter C. Brown et Maureen Costello. Isolating a Cell Maximally Secreting Acetylcholinesterase. Fort Belvoir, VA : Defense Technical Information Center, juillet 1986. http://dx.doi.org/10.21236/ada211825.

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Rose, Sam, Peter C. Brown et Maureen Costello. Isolating a Cell Maximally Secreting Acetylcholinesterase. Fort Belvoir, VA : Defense Technical Information Center, mai 1987. http://dx.doi.org/10.21236/ada211827.

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Flowers, Ann M. Secretion of Heterologous Proteins from Escherichia coli. Fort Belvoir, VA : Defense Technical Information Center, décembre 2000. http://dx.doi.org/10.21236/ada391190.

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Vogel, Christine. Preventing Prostate Cancer Metastasis by Targeting Exosome Secretion. Fort Belvoir, VA : Defense Technical Information Center, octobre 2014. http://dx.doi.org/10.21236/ada611806.

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Starmer, Frank. Models of Excitation-Secretion Coupling in Pituitary Cells. Fort Belvoir, VA : Defense Technical Information Center, juin 1991. http://dx.doi.org/10.21236/ada238594.

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Chuck, Steven L. The Non-Classical Secretion of Thioredoxin from Breast Cancer Cells. Fort Belvoir, VA : Defense Technical Information Center, juin 2002. http://dx.doi.org/10.21236/ada407677.

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Chuck, Steven L. The Non-Classical Secretion of Thioredoxin from Breast Cancer Cells. Fort Belvoir, VA : Defense Technical Information Center, juin 2004. http://dx.doi.org/10.21236/ada426431.

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Chuck, Steven L. The Non-Classical Secretion of Thioredoxin from Breast Cancer Cells. Fort Belvoir, VA : Defense Technical Information Center, juin 2003. http://dx.doi.org/10.21236/ada425885.

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Bartlow, Frederick. Factors affecting thyrotropin secretion in superfused rat anterior pituitary cells. Portland State University Library, janvier 2000. http://dx.doi.org/10.15760/etd.3133.

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Elbaum, Michael, et Peter J. Christie. Type IV Secretion System of Agrobacterium tumefaciens : Components and Structures. United States Department of Agriculture, mars 2013. http://dx.doi.org/10.32747/2013.7699848.bard.

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Objectives: The overall goal of the project was to build an ultrastructural model of the Agrobacterium tumefaciens type IV secretion system (T4SS) based on electron microscopy, genetics, and immunolocalization of its components. There were four original aims: Aim 1: Define the contributions of contact-dependent and -independent plant signals to formation of novel morphological changes at the A. tumefaciens polar membrane. Aim 2: Genetic basis for morphological changes at the A. tumefaciens polar membrane. Aim 3: Immuno-localization of VirB proteins Aim 4: Structural definition of the substrate translocation route. There were no major revisions to the aims, and the work focused on the above questions. Background: Agrobacterium presents a unique example of inter-kingdom gene transfer. The process involves cell to cell transfer of both protein and DNA substrates via a contact-dependent mechanism akin to bacterial conjugation. Transfer is mediated by a T4SS. Intensive study of the Agrobacterium T4SS has made it an archetypal model for the genetics and biochemistry. The channel is assembled from eleven protein components encoded on the B operon in the virulence region of the tumor-inducing plasmid, plus an additional coupling protein, VirD4. During the course of our project two structural studies were published presenting X-ray crystallography and three-dimensional reconstruction from electron microscopy of a core complex of the channel assembled in vitro from homologous proteins of E. coli, representing VirB7, VirB9, and VirB10. Another study was published claiming that the secretion channels in Agrobacterium appear on helical arrays around the membrane perimeter and along the entire length of the bacterium. Helical arrangements in bacterial membranes have since fallen from favor however, and that finding was partially retracted in a second publication. Overall, the localization of the T4SS within the bacterial membranes remains enigmatic in the literature, and we believe that our results from this project make a significant advance. Summary of achievements : We found that polar inflations and other membrane disturbances relate to the activation conditions rather than to virulence protein expression. Activation requires low pH and nutrient-poor medium. These stress conditions are also reflected in DNA condensation to varying degrees. Nonetheless, they must be considered in modeling the T4SS as they represent the relevant conditions for its expression and activity. We identified the T4SS core component VirB7 at native expression levels using state of the art super-resolution light microscopy. This marker of the secretion system was found almost exclusively at the cell poles, and typically one pole. Immuno-electron microscopy identified the protein at the inner membrane, rather than at bridges across the inner and outer membranes. This suggests a rare or transient assembly of the secretion-competent channel, or alternatively a two-step secretion involving an intermediate step in the periplasmic space. We followed the expression of the major secreted effector, VirE2. This is a single-stranded DNA binding protein that forms a capsid around the transferred oligonucleotide, adapting the bacterial conjugation to the eukaryotic host. We found that over-expressed VirE2 forms filamentous complexes in the bacterial cytoplasm that could be observed both by conventional fluorescence microscopy and by correlative electron cryo-tomography. Using a non-retentive mutant we observed secretion of VirE2 from bacterial poles. We labeled the secreted substrates in vivo in order detect their secretion and appearance in the plant cells. However the low transfer efficiency and significant background signal have so far hampered this approach.
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