The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Esabi Basaran Kurbanoglu - One of the best experts on this subject based on the ideXlab platform.
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Citric Acid Production by Aspergillus niger from Agro-Industrial By-Products: Molasses and Chicken Feather Peptone
Waste and Biomass Valorization, 2019Co-Authors: Murat Ozdal, Esabi Basaran KurbanogluAbstract:Citric acid is a commercially important organic acid with a wide range of applications. To reduce the cost of producing citric acid, sugar beet molasses and chicken feather Peptone (CFP) were used as the sole carbon and nitrogen sources, respectively for submerged citric acid biosynthesis using Aspergillus niger . To improve the citric acid production, the parental isolate of A. niger MO-25 was improved by mutation using ethidium bromide. Citric acid production using molasses was significantly affected by CFP concentrations (1–6 g/L). The maximum citric acid concentration was determined at 4 g/L CFP and 168 h. When CFP compared to commercial Peptones (casein and bacto), the highest citric acid production was obtained with CFP. Furthermore, the addition of KH_2PO_4 (0.15 g/L) enhanced citric acid production (68.8 g/L). These results suggested that sugar beet molasses supplemented with CFP as organic nitrogen and mineral salt sources could be utilized for the economical and efficient production of citric acid. This is the first study to investigate the influence of CFP for citric acid production. Graphical Abstract
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Use of Chicken Feather Peptone and Sugar Beet Molasses as Low Cost Substrates for Xanthan Production by Xanthomonas campestris MO-03
MDPI AG, 2019Co-Authors: Murat Ozdal, Esabi Basaran KurbanogluAbstract:Xanthan gum is one of the polysaccharides most commonly used in a broad range of industries (food, cosmetics, pharmaceutical, etc.). Agro-industrial by-products are being explored as alternative low-cost nutrients to produce xanthan gum by Xanthomonas campestris. In this study, for the production of xanthan gum, sugar beet molasses and chicken feather Peptone (CFP) were used as carbon and nitrogen sources, respectively. X. campestris produced the highest level of xanthan gum (20.5 g/L) at 60 h of cultivation using sugar beet molasses (40 g/L total sugar) supplemented with CFP (4 g/L) at pH 7, 200 rpm, and 30 °C. The pyruvic acid content of the xanthan gums increased with increasing CFP concentration. Compared with commercial organic nitrogen sources (tryptone, bacto Peptone, and yeast extract), the highest production of xanthan gum was obtained with CFP. Moreover, among the tested Peptones, the highest pyruvic acid (3.2%, w/w) content was obtained from CFP. The usage of sugar beet molasses and CFP as substrates in industries would enable a cost-efficient commercial production. These results suggest that sugar beet molasses and CFP can be used as available low-cost substrates for xanthan gum production by X. campestris
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enhanced production of prodigiosin by serratia marcescens mo 1 using ram horn Peptone
Brazilian Journal of Microbiology, 2015Co-Authors: Esabi Basaran Kurbanoglu, Murat Ozdal, Ozlem Gur Ozdal, Omer Faruk AlgurAbstract:This work addresses the production of prodigiosin from ram horn Peptone (RHP) using MO-1, a local isolate in submerged culture. First, a novel gram-negative and rod-shaped bacterial strain, MO-1, was isolated from the body of the grasshopper (Poecilemon tauricola Ramme 1951), which was collected from pesticide-contaminated fields. Sequence analysis of 16S rDNA classified the microbe as Serratia marcescens. The substrate utilization potential (BIOLOG) and fatty acid methyl ester profile (FAME) of S. marcescens were also determined. The effect of RHP on the production of prodigiosin by S. marcescens MO-1 was investigated, and the results showed that RHP supplementation promoted the growth of MO-1 and increased the production of prodigiosin. A concentration of 0.4% (w/v) RHP resulted in the greatest yield of prodigiosin (277.74 mg/L) after 48 h when mannitol was used as the sole source of carbon. The pigment yield was also influenced by the types of carbon sources and Peptones. As a result, RHP was demonstrated to be a suitable substrate for prodigiosin production. These results revealed that prodigiosin could be produced efficiently by S. marcescens using RHP.
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use of waste chicken feathers as Peptone for production of carotenoids in submerged culture of rhodotorula glutinis mt 5
European Food Research and Technology, 2011Co-Authors: Mesut Taskin, Turgay Sisman, Serkan Erdal, Esabi Basaran KurbanogluAbstract:Peptones are one of the most expensive constituents of fermentation media. The present study was performed to prepare the Peptone from waste chicken feathers through acid hydrolysis and to investigate the usability of this Peptone as substrate for biomass and carotenoid production by Rhodotorula glutinis MT-5. Chicken feather Peptone (CFP) was found to be rich in ash (42.1 g/100 g), protein (55.8 g/100 g) and mineral contents. The ability of CFP to support biomass and carotenoid production in the yeast was comparable to those of two commercial Peptones (Tryptone Peptone = TP and Fish Peptone = FP). The optimum concentration of CFP was found to be 8 g/L for both biomass and carotenoid production. Adding 8 g/L CFP to the medium increased carotenoid and biomass production about 53 and 36% compared to control, respectively. At the end of the fermentation, the maximum biomass (14.2 g/L) and carotenoid (92 mg/L) concentrations were achieved with CFP. Moreover, the maximum carotenoid yield (6.47 mg/g) was reached in CFP medium. This study showed for the first time that waste chicken feathers could be effectively used as a novel carotenoid production substrate for R. glutinis.
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Evaluation of waste chicken feathers as Peptone source for bacterial growth
Journal of applied microbiology, 2011Co-Authors: Mesut Taskin, Esabi Basaran KurbanogluAbstract:Aims: Peptones are one of the most expensive constituents of microbial media. This study was undertaken to prepare the Peptone from waste chicken feathers through a new process. Methods and Results: The chemical analysis of chicken feather Peptone (CFP) was performed. The ability of CFP to support the growth of the three test bacteria in liquid and agar media was comparable to those of three commercial Peptones [tryptone Peptone (TP), fish Peptone and protease Peptone (PP)]. Conclusions: CFP was found to be rich in ash (42·1 g 100 g−1), protein (55·8 g 100 g−1) and mineral contents. The maximum biomass yield (3·13 g l−1) and colony number (83 × 108 CFU ml−1) for bacterium Bacillus subtilis were attained with CFP. The maximum biomass yields and colony numbers for Lactobacillus delbrueckii ssp. bulgaricus and Escherichia coli were reached in TP medium. Second high biomass yield (2·64 g l−1) and colony number (75 × 108 CFU ml−1) for E. coli were achieved using CFP. Third high biomass yield (1·29 g l−1) and colony number (90 × 107 CFU ml−1) for Lact. delbrueckii ssp. bulgaricus were obtained in CFP medium. Significance and Impact of the Study: Usability of waste chicken feathers as substrate for bacteria was investigated for the first time in the present study. The Peptone may be used in industrial fermentations for production of antibiotics, organic acids, enzymes and biopolymer. It may be also used in clinical microbiology. A new chemical process was developed for Peptone preparation. This process may be also employed for Peptone preparation from other organic materials, especially fibrose protein-containing materials.
J C Cuber - One of the best experts on this subject based on the ideXlab platform.
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Peptones stimulate both the secretion of the incretin hormone glucagon like peptide 1 and the transcription of the proglucagon gene
Diabetes, 1998Co-Authors: Martine Cordierbussat, Christine Bernard, J A Chayvialle, F Levenez, N Klages, B Laserritz, Jacques Philippe, J C CuberAbstract:Truncated glucagon-like peptide (GLP)-1 is a potent incretin. Its synthesis and secretion are modulated by food, but the influence of individual nutrients remains to be established. The hypothesis that protein hydrolysates (Peptones) can directly regulate both GLP-1 secretion and proglucagon (PG) gene transcription was tested in this study, ex vivo in the isolated vascularly perfused rat intestine and in vitro in the murine enteroendocrine cell line STC-1. Peptones were albumin egg hydrolysate (AEH) and meat hydrolysate (MH). We demonstrate in these two models that Peptones dose-dependently stimulate GLP-1 release, whereas isocaloric quantities of bovine serum albumin or of an amino acid mixture had no stimulatory effect. A strong and rapid increase of PG RNA level was observed in STC-1 cells treated with Peptones (14-fold and 7-fold increase after 4 h of incubation with 3% wt/vol MH and AEH, respectively). Peptones also increased the PG RNA level in the colonic PG-expressing cell line GLUTag. In contrast, Peptones did not modify the PG RNA level in two pancreatic glucagon-producing cell lines, namely, the RINm5F and INR1G9 cells. The Peptone effect in STC-1 cells was completely abolished by blocking transcription before MH treatment. The stability of proglugacon transcripts was not modified by MH treatment, but nascent transcripts were more abundant in STC-1 cells preincubated with MH. Finally, MH treatment strongly stimulated (15-fold stimulation) the transcriptional activity of two PG gene promoter fragments (-1100 and -350 base pair) linked to the CAT reporter gene transiently transfected in STC-1 cells. Overall, Peptones evoke an as yet undescribed release of GLP-1 when brought into contact with native intestinal L-cells or with STC-1 enteroendocrine cells. The increased transcription of the glucagon gene in the latter system suggests an important role of protein hydrolysates in the control of not only the secretion but also the synthesis of the incretin hormone.
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regulation of cholecystokinin secretion by Peptones and peptidomimetic antibiotics in stc 1 cells
Endocrinology, 1998Co-Authors: Eric Nemozgaillard, Martine Cordierbussat, Christine Bernard, Jacques Abello, J A Chayvialle, J C CuberAbstract:Peptones are potent stimulants of cholecystokinin (CCK) release in rats, both in vivo and ex vivo in a model of isolated vascularly perfused duodeno-jejunum preparation and in vitro in the intestinal CCK-producing cell line STC-1. The underlying mechanisms were here investigated with this cell line. Protein hydrolysates from various origins (meat, casein, soybean, and ovalbumin; 0.5-1%, wt/vol) dose dependently increased CCK release. Cephalosporin antibiotics, which mimic tripeptides, also stimulated the release of CCK over the concentration range 1-20 mM. The study of concentration dependence of cephalosporin uptake indicated a passive diffusion process at either pH 7.4 or pH 6.0, thus arguing against the involvement of a peptide transporter in CCK secretion. After pertussis toxin treatment (200 ng/ml; 5 h), the Peptone- and cephalexin-induced CCK secretion was significantly reduced, suggesting the involvement of pertussis toxin-sensitive heterotrimeric G protein(s) in the secretory activity of STC-1 cells. Consistent with this was the identification by Western blot of G(i2)alpha, G(i3)alpha, and G(o)alpha immunoreactivities in STC-1 cell extracts. Additionally, Peptones and cephalexin increased the cellular content in inositol phosphates, whereas a mild increase in cAMP content was restricted to Peptone-treated cells. Protein kinase A or C inhibition did not modify Peptone- or antibiotic drug-evoked CCK release. The extracellular Ca2+ chelator EGTA (500 microM) and the intracellular Ca2+ chelator BAPTA-AM [1,2-bis-(O-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetra(acetoxymethyl) ester; 20 microM] abolished the Peptone- and antibiotic drug-induced CCK release. Nifedipine and verapamil (10 microM) reduced by about 50% the CCK secretion evoked by these two secretagogues. In conclusion, Peptones and some cephalosporins are potent stimulants of CCK release in the STC-1 cell line. The cellular mechanisms involve pertussis toxin-sensitive G protein(s) and are dependent on Ca2+ availability. We suggest that the STC-1 cell line is a useful model to study the molecular basis of Peptone-induced CCK secretion.
Martine Cordierbussat - One of the best experts on this subject based on the ideXlab platform.
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Peptones stimulate intestinal cholecystokinin gene transcription via cyclic adenosine monophosphate response element binding factors
Endocrinology, 2001Co-Authors: Christine Bernard, J A Chayvialle, Anne Sutter, Charles Vinson, Christelle Ratineau, Martine CordierbussatAbstract:Cholecystokinin (CCK) is a potent intestinal hormone that regulates several digestive functions. Despite the physiological importance of CCK, the cellular and molecular mechanisms that govern its synthesis and secretion are not completely identified. Peptones, which are fair counterparts of the protein fraction in the intestinal lumen, are good stimulants of CCK secretion. We have previously shown that Peptones activate CCK gene transcription in STC-1 enteroendocrine cells. The DNA element(s) necessary to induce the transcriptional stimulation was preliminary, localized in the first 800 bp of the CCK gene promoter. In the present study, we identify a DNA element [Peptone-response element (PepRE)] essential to confer Peptone-responsiveness to the CCK promoter, and we characterize the transcription factors implicated. Localization of the PepRE between −93 and −70 bp of the promoter was established using serial 5′-3′deletions. Systematic site-directed mutagenesis demonstrated that the core PepRE sequence, sp...
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Peptones stimulate both the secretion of the incretin hormone glucagon like peptide 1 and the transcription of the proglucagon gene
Diabetes, 1998Co-Authors: Martine Cordierbussat, Christine Bernard, J A Chayvialle, F Levenez, N Klages, B Laserritz, Jacques Philippe, J C CuberAbstract:Truncated glucagon-like peptide (GLP)-1 is a potent incretin. Its synthesis and secretion are modulated by food, but the influence of individual nutrients remains to be established. The hypothesis that protein hydrolysates (Peptones) can directly regulate both GLP-1 secretion and proglucagon (PG) gene transcription was tested in this study, ex vivo in the isolated vascularly perfused rat intestine and in vitro in the murine enteroendocrine cell line STC-1. Peptones were albumin egg hydrolysate (AEH) and meat hydrolysate (MH). We demonstrate in these two models that Peptones dose-dependently stimulate GLP-1 release, whereas isocaloric quantities of bovine serum albumin or of an amino acid mixture had no stimulatory effect. A strong and rapid increase of PG RNA level was observed in STC-1 cells treated with Peptones (14-fold and 7-fold increase after 4 h of incubation with 3% wt/vol MH and AEH, respectively). Peptones also increased the PG RNA level in the colonic PG-expressing cell line GLUTag. In contrast, Peptones did not modify the PG RNA level in two pancreatic glucagon-producing cell lines, namely, the RINm5F and INR1G9 cells. The Peptone effect in STC-1 cells was completely abolished by blocking transcription before MH treatment. The stability of proglugacon transcripts was not modified by MH treatment, but nascent transcripts were more abundant in STC-1 cells preincubated with MH. Finally, MH treatment strongly stimulated (15-fold stimulation) the transcriptional activity of two PG gene promoter fragments (-1100 and -350 base pair) linked to the CAT reporter gene transiently transfected in STC-1 cells. Overall, Peptones evoke an as yet undescribed release of GLP-1 when brought into contact with native intestinal L-cells or with STC-1 enteroendocrine cells. The increased transcription of the glucagon gene in the latter system suggests an important role of protein hydrolysates in the control of not only the secretion but also the synthesis of the incretin hormone.
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regulation of cholecystokinin secretion by Peptones and peptidomimetic antibiotics in stc 1 cells
Endocrinology, 1998Co-Authors: Eric Nemozgaillard, Martine Cordierbussat, Christine Bernard, Jacques Abello, J A Chayvialle, J C CuberAbstract:Peptones are potent stimulants of cholecystokinin (CCK) release in rats, both in vivo and ex vivo in a model of isolated vascularly perfused duodeno-jejunum preparation and in vitro in the intestinal CCK-producing cell line STC-1. The underlying mechanisms were here investigated with this cell line. Protein hydrolysates from various origins (meat, casein, soybean, and ovalbumin; 0.5-1%, wt/vol) dose dependently increased CCK release. Cephalosporin antibiotics, which mimic tripeptides, also stimulated the release of CCK over the concentration range 1-20 mM. The study of concentration dependence of cephalosporin uptake indicated a passive diffusion process at either pH 7.4 or pH 6.0, thus arguing against the involvement of a peptide transporter in CCK secretion. After pertussis toxin treatment (200 ng/ml; 5 h), the Peptone- and cephalexin-induced CCK secretion was significantly reduced, suggesting the involvement of pertussis toxin-sensitive heterotrimeric G protein(s) in the secretory activity of STC-1 cells. Consistent with this was the identification by Western blot of G(i2)alpha, G(i3)alpha, and G(o)alpha immunoreactivities in STC-1 cell extracts. Additionally, Peptones and cephalexin increased the cellular content in inositol phosphates, whereas a mild increase in cAMP content was restricted to Peptone-treated cells. Protein kinase A or C inhibition did not modify Peptone- or antibiotic drug-evoked CCK release. The extracellular Ca2+ chelator EGTA (500 microM) and the intracellular Ca2+ chelator BAPTA-AM [1,2-bis-(O-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetra(acetoxymethyl) ester; 20 microM] abolished the Peptone- and antibiotic drug-induced CCK release. Nifedipine and verapamil (10 microM) reduced by about 50% the CCK secretion evoked by these two secretagogues. In conclusion, Peptones and some cephalosporins are potent stimulants of CCK release in the STC-1 cell line. The cellular mechanisms involve pertussis toxin-sensitive G protein(s) and are dependent on Ca2+ availability. We suggest that the STC-1 cell line is a useful model to study the molecular basis of Peptone-induced CCK secretion.
Christine Bernard - One of the best experts on this subject based on the ideXlab platform.
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Printed in U.S.A. Copyright © 1997 by The Endocrine Society Peptones Stimulate Cholecystokinin Secretion and Gene Transcription in the Intestinal Cell Line STC-1*
2013Co-Authors: Martine Cordier-bussat, Christine Bernard, Sophia Haouche, Colette Roche, Jacques Abello, J A ChayvialleAbstract:In rats, protein hydrolysates (Peptones) stimulate cholecystokinin (CCK) release both in vivo and in a model of isolated vascularly perfused duodeno-jejunum. However, the mechanisms involved in Peptone-induced stimulation of CCK cells are not well understood. In particular, the possibility that Peptones may directly interact with CCK-producing cells to stimulate CCK release and gene transcription has not yet been examined. To test this hypothesis, we used the enteroendocrine cell line STC-1. Incubation of STC-1 cells for 2 h with albumin egg hydrolysate over the concentration range 0.01–1 % (wt/ vol) caused a dose-dependent release of CCK, with a maximal increase at 1420 % of the control value. In contrast, BSA (1%, wt/vol) or a mixture of amino acids (1%, wt/vol) induced a modest rise in CCK secretion. A dose-dependent, hydrolysate-specific, increase in the CCK steady state RNA level was also observed. It was detectable b
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Peptones stimulate intestinal cholecystokinin gene transcription via cyclic adenosine monophosphate response element binding factors
Endocrinology, 2001Co-Authors: Christine Bernard, J A Chayvialle, Anne Sutter, Charles Vinson, Christelle Ratineau, Martine CordierbussatAbstract:Cholecystokinin (CCK) is a potent intestinal hormone that regulates several digestive functions. Despite the physiological importance of CCK, the cellular and molecular mechanisms that govern its synthesis and secretion are not completely identified. Peptones, which are fair counterparts of the protein fraction in the intestinal lumen, are good stimulants of CCK secretion. We have previously shown that Peptones activate CCK gene transcription in STC-1 enteroendocrine cells. The DNA element(s) necessary to induce the transcriptional stimulation was preliminary, localized in the first 800 bp of the CCK gene promoter. In the present study, we identify a DNA element [Peptone-response element (PepRE)] essential to confer Peptone-responsiveness to the CCK promoter, and we characterize the transcription factors implicated. Localization of the PepRE between −93 and −70 bp of the promoter was established using serial 5′-3′deletions. Systematic site-directed mutagenesis demonstrated that the core PepRE sequence, sp...
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Peptones stimulate both the secretion of the incretin hormone glucagon like peptide 1 and the transcription of the proglucagon gene
Diabetes, 1998Co-Authors: Martine Cordierbussat, Christine Bernard, J A Chayvialle, F Levenez, N Klages, B Laserritz, Jacques Philippe, J C CuberAbstract:Truncated glucagon-like peptide (GLP)-1 is a potent incretin. Its synthesis and secretion are modulated by food, but the influence of individual nutrients remains to be established. The hypothesis that protein hydrolysates (Peptones) can directly regulate both GLP-1 secretion and proglucagon (PG) gene transcription was tested in this study, ex vivo in the isolated vascularly perfused rat intestine and in vitro in the murine enteroendocrine cell line STC-1. Peptones were albumin egg hydrolysate (AEH) and meat hydrolysate (MH). We demonstrate in these two models that Peptones dose-dependently stimulate GLP-1 release, whereas isocaloric quantities of bovine serum albumin or of an amino acid mixture had no stimulatory effect. A strong and rapid increase of PG RNA level was observed in STC-1 cells treated with Peptones (14-fold and 7-fold increase after 4 h of incubation with 3% wt/vol MH and AEH, respectively). Peptones also increased the PG RNA level in the colonic PG-expressing cell line GLUTag. In contrast, Peptones did not modify the PG RNA level in two pancreatic glucagon-producing cell lines, namely, the RINm5F and INR1G9 cells. The Peptone effect in STC-1 cells was completely abolished by blocking transcription before MH treatment. The stability of proglugacon transcripts was not modified by MH treatment, but nascent transcripts were more abundant in STC-1 cells preincubated with MH. Finally, MH treatment strongly stimulated (15-fold stimulation) the transcriptional activity of two PG gene promoter fragments (-1100 and -350 base pair) linked to the CAT reporter gene transiently transfected in STC-1 cells. Overall, Peptones evoke an as yet undescribed release of GLP-1 when brought into contact with native intestinal L-cells or with STC-1 enteroendocrine cells. The increased transcription of the glucagon gene in the latter system suggests an important role of protein hydrolysates in the control of not only the secretion but also the synthesis of the incretin hormone.
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regulation of cholecystokinin secretion by Peptones and peptidomimetic antibiotics in stc 1 cells
Endocrinology, 1998Co-Authors: Eric Nemozgaillard, Martine Cordierbussat, Christine Bernard, Jacques Abello, J A Chayvialle, J C CuberAbstract:Peptones are potent stimulants of cholecystokinin (CCK) release in rats, both in vivo and ex vivo in a model of isolated vascularly perfused duodeno-jejunum preparation and in vitro in the intestinal CCK-producing cell line STC-1. The underlying mechanisms were here investigated with this cell line. Protein hydrolysates from various origins (meat, casein, soybean, and ovalbumin; 0.5-1%, wt/vol) dose dependently increased CCK release. Cephalosporin antibiotics, which mimic tripeptides, also stimulated the release of CCK over the concentration range 1-20 mM. The study of concentration dependence of cephalosporin uptake indicated a passive diffusion process at either pH 7.4 or pH 6.0, thus arguing against the involvement of a peptide transporter in CCK secretion. After pertussis toxin treatment (200 ng/ml; 5 h), the Peptone- and cephalexin-induced CCK secretion was significantly reduced, suggesting the involvement of pertussis toxin-sensitive heterotrimeric G protein(s) in the secretory activity of STC-1 cells. Consistent with this was the identification by Western blot of G(i2)alpha, G(i3)alpha, and G(o)alpha immunoreactivities in STC-1 cell extracts. Additionally, Peptones and cephalexin increased the cellular content in inositol phosphates, whereas a mild increase in cAMP content was restricted to Peptone-treated cells. Protein kinase A or C inhibition did not modify Peptone- or antibiotic drug-evoked CCK release. The extracellular Ca2+ chelator EGTA (500 microM) and the intracellular Ca2+ chelator BAPTA-AM [1,2-bis-(O-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetra(acetoxymethyl) ester; 20 microM] abolished the Peptone- and antibiotic drug-induced CCK release. Nifedipine and verapamil (10 microM) reduced by about 50% the CCK secretion evoked by these two secretagogues. In conclusion, Peptones and some cephalosporins are potent stimulants of CCK release in the STC-1 cell line. The cellular mechanisms involve pertussis toxin-sensitive G protein(s) and are dependent on Ca2+ availability. We suggest that the STC-1 cell line is a useful model to study the molecular basis of Peptone-induced CCK secretion.
J A Chayvialle - One of the best experts on this subject based on the ideXlab platform.
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Printed in U.S.A. Copyright © 1997 by The Endocrine Society Peptones Stimulate Cholecystokinin Secretion and Gene Transcription in the Intestinal Cell Line STC-1*
2013Co-Authors: Martine Cordier-bussat, Christine Bernard, Sophia Haouche, Colette Roche, Jacques Abello, J A ChayvialleAbstract:In rats, protein hydrolysates (Peptones) stimulate cholecystokinin (CCK) release both in vivo and in a model of isolated vascularly perfused duodeno-jejunum. However, the mechanisms involved in Peptone-induced stimulation of CCK cells are not well understood. In particular, the possibility that Peptones may directly interact with CCK-producing cells to stimulate CCK release and gene transcription has not yet been examined. To test this hypothesis, we used the enteroendocrine cell line STC-1. Incubation of STC-1 cells for 2 h with albumin egg hydrolysate over the concentration range 0.01–1 % (wt/ vol) caused a dose-dependent release of CCK, with a maximal increase at 1420 % of the control value. In contrast, BSA (1%, wt/vol) or a mixture of amino acids (1%, wt/vol) induced a modest rise in CCK secretion. A dose-dependent, hydrolysate-specific, increase in the CCK steady state RNA level was also observed. It was detectable b
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Peptones stimulate intestinal cholecystokinin gene transcription via cyclic adenosine monophosphate response element binding factors
Endocrinology, 2001Co-Authors: Christine Bernard, J A Chayvialle, Anne Sutter, Charles Vinson, Christelle Ratineau, Martine CordierbussatAbstract:Cholecystokinin (CCK) is a potent intestinal hormone that regulates several digestive functions. Despite the physiological importance of CCK, the cellular and molecular mechanisms that govern its synthesis and secretion are not completely identified. Peptones, which are fair counterparts of the protein fraction in the intestinal lumen, are good stimulants of CCK secretion. We have previously shown that Peptones activate CCK gene transcription in STC-1 enteroendocrine cells. The DNA element(s) necessary to induce the transcriptional stimulation was preliminary, localized in the first 800 bp of the CCK gene promoter. In the present study, we identify a DNA element [Peptone-response element (PepRE)] essential to confer Peptone-responsiveness to the CCK promoter, and we characterize the transcription factors implicated. Localization of the PepRE between −93 and −70 bp of the promoter was established using serial 5′-3′deletions. Systematic site-directed mutagenesis demonstrated that the core PepRE sequence, sp...
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Peptones stimulate both the secretion of the incretin hormone glucagon like peptide 1 and the transcription of the proglucagon gene
Diabetes, 1998Co-Authors: Martine Cordierbussat, Christine Bernard, J A Chayvialle, F Levenez, N Klages, B Laserritz, Jacques Philippe, J C CuberAbstract:Truncated glucagon-like peptide (GLP)-1 is a potent incretin. Its synthesis and secretion are modulated by food, but the influence of individual nutrients remains to be established. The hypothesis that protein hydrolysates (Peptones) can directly regulate both GLP-1 secretion and proglucagon (PG) gene transcription was tested in this study, ex vivo in the isolated vascularly perfused rat intestine and in vitro in the murine enteroendocrine cell line STC-1. Peptones were albumin egg hydrolysate (AEH) and meat hydrolysate (MH). We demonstrate in these two models that Peptones dose-dependently stimulate GLP-1 release, whereas isocaloric quantities of bovine serum albumin or of an amino acid mixture had no stimulatory effect. A strong and rapid increase of PG RNA level was observed in STC-1 cells treated with Peptones (14-fold and 7-fold increase after 4 h of incubation with 3% wt/vol MH and AEH, respectively). Peptones also increased the PG RNA level in the colonic PG-expressing cell line GLUTag. In contrast, Peptones did not modify the PG RNA level in two pancreatic glucagon-producing cell lines, namely, the RINm5F and INR1G9 cells. The Peptone effect in STC-1 cells was completely abolished by blocking transcription before MH treatment. The stability of proglugacon transcripts was not modified by MH treatment, but nascent transcripts were more abundant in STC-1 cells preincubated with MH. Finally, MH treatment strongly stimulated (15-fold stimulation) the transcriptional activity of two PG gene promoter fragments (-1100 and -350 base pair) linked to the CAT reporter gene transiently transfected in STC-1 cells. Overall, Peptones evoke an as yet undescribed release of GLP-1 when brought into contact with native intestinal L-cells or with STC-1 enteroendocrine cells. The increased transcription of the glucagon gene in the latter system suggests an important role of protein hydrolysates in the control of not only the secretion but also the synthesis of the incretin hormone.
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regulation of cholecystokinin secretion by Peptones and peptidomimetic antibiotics in stc 1 cells
Endocrinology, 1998Co-Authors: Eric Nemozgaillard, Martine Cordierbussat, Christine Bernard, Jacques Abello, J A Chayvialle, J C CuberAbstract:Peptones are potent stimulants of cholecystokinin (CCK) release in rats, both in vivo and ex vivo in a model of isolated vascularly perfused duodeno-jejunum preparation and in vitro in the intestinal CCK-producing cell line STC-1. The underlying mechanisms were here investigated with this cell line. Protein hydrolysates from various origins (meat, casein, soybean, and ovalbumin; 0.5-1%, wt/vol) dose dependently increased CCK release. Cephalosporin antibiotics, which mimic tripeptides, also stimulated the release of CCK over the concentration range 1-20 mM. The study of concentration dependence of cephalosporin uptake indicated a passive diffusion process at either pH 7.4 or pH 6.0, thus arguing against the involvement of a peptide transporter in CCK secretion. After pertussis toxin treatment (200 ng/ml; 5 h), the Peptone- and cephalexin-induced CCK secretion was significantly reduced, suggesting the involvement of pertussis toxin-sensitive heterotrimeric G protein(s) in the secretory activity of STC-1 cells. Consistent with this was the identification by Western blot of G(i2)alpha, G(i3)alpha, and G(o)alpha immunoreactivities in STC-1 cell extracts. Additionally, Peptones and cephalexin increased the cellular content in inositol phosphates, whereas a mild increase in cAMP content was restricted to Peptone-treated cells. Protein kinase A or C inhibition did not modify Peptone- or antibiotic drug-evoked CCK release. The extracellular Ca2+ chelator EGTA (500 microM) and the intracellular Ca2+ chelator BAPTA-AM [1,2-bis-(O-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetra(acetoxymethyl) ester; 20 microM] abolished the Peptone- and antibiotic drug-induced CCK release. Nifedipine and verapamil (10 microM) reduced by about 50% the CCK secretion evoked by these two secretagogues. In conclusion, Peptones and some cephalosporins are potent stimulants of CCK release in the STC-1 cell line. The cellular mechanisms involve pertussis toxin-sensitive G protein(s) and are dependent on Ca2+ availability. We suggest that the STC-1 cell line is a useful model to study the molecular basis of Peptone-induced CCK secretion.
