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Sample records for secreted klotho mechanisms

  1. The vascular secret of Klotho

    DEFF Research Database (Denmark)

    Lewin, Ewa; Olgaard, Klaus

    2015-01-01

    Klotho is an evolutionarily highly conserved protein related to longevity. Increasing evidence of a vascular protecting effect of the Klotho protein has emerged and might be important for future treatments of uremic vascular calcification. It is still disputed whether Klotho is locally expressed ...

  2. SECRETED KLOTHO AND CHRONIC KIDNEY DISEASE

    Science.gov (United States)

    Hu, Ming Chang; Kuro-o, Makoto; Moe, Orson W.

    2013-01-01

    Soluble Klotho (sKl) in the circulation can be generated directly by alterative splicing of the Klotho transcript or the extracellular domain of membrane Klotho can be released from membrane-anchored Klotho on the cell surface. Unlike membrane Klotho which functions as a coreceptor for fibroblast growth factor-23 (FGF23), sKl, acts as hormonal factor and plays important roles in anti-aging, anti-oxidation, modulation of ion transport, and Wnt signaling. Emerging evidence reveals that Klotho deficiency is an early biomarker for chronic kidney diseases as well as a pathogenic factor. Klotho deficiency is associated with progression and chronic complications in chronic kidney disease including vascular calcification, cardiac hypertrophy, and secondary hyperparathyroidism. In multiple experimental models, replacement of sKl, or manipulated up-regulation of endogenous Klotho protect the kidney from renal insults, preserve kidney function, and suppress renal fibrosis, in chronic kidney disease. Klotho is a highly promising candidate on the horizon as an early biomarker, and as a novel therapeutic agent for chronic kidney disease. PMID:22396167

  3. Secreted and Transmembrane αKlotho Isoforms Have Different Spatio-Temporal Profiles in the Brain during Aging and Alzheimer's Disease Progression.

    Directory of Open Access Journals (Sweden)

    Anna Massó

    Full Text Available The Klotho protein is a β-glucuronidase, and its overexpression is associated with life extension. Its mechanism of action is not fully understood, although it has been recently reported that αKlotho improves synaptic and cognitive functions, and it may also influence a variety of structures and functions during CNS maturation and aging. The αKlotho gene has two transcripts, one encoding a transmembrane isoform (m-KL, and the other a putative secreted isoform (s-KL. Unfortunately, little is known about the secreted αKlotho isoform, since available antibodies cannot discriminate s-KL from the KL1 domain cleaved from the transmembrane isoform. This study shows, for the first time, that the klotho transcript produced by alternative splicing generates a stable protein (70 kDa, and that in contrast to the transmembrane Klotho isoform, it is ten times more abundant in the brain than in the kidney suggesting that the two isoforms may have different functions. We also studied whether klotho expression in the CNS was influenced by aging, Alzheimer's disease (AD, or a healthy lifestyle, such as voluntary moderate continuous exercise. We observed a strong correlation between high expression levels of the two klotho transcripts and the healthy status of the animals. Expression of Klotho in brain areas decayed more rapidly in the 3xTg-AD model of AD than in healthy animals, whilst moderate continuous exercise in adulthood prevents the decline in expression of both klotho transcripts.

  4. Secreted and Transmembrane αKlotho Isoforms Have Different Spatio-Temporal Profiles in the Brain during Aging and Alzheimer's Disease Progression

    Science.gov (United States)

    Massó, Anna; Sánchez, Angela; Gimenez-Llort, Lydia; Lizcano, Jose Miguel; Cañete, Manuel; García, Belen; Torres-Lista, Virginia; Puig, Meritxell; Bosch, Assumpció; Chillon, Miguel

    2015-01-01

    The Klotho protein is a β-glucuronidase, and its overexpression is associated with life extension. Its mechanism of action is not fully understood, although it has been recently reported that αKlotho improves synaptic and cognitive functions, and it may also influence a variety of structures and functions during CNS maturation and aging. The αKlotho gene has two transcripts, one encoding a transmembrane isoform (m-KL), and the other a putative secreted isoform (s-KL). Unfortunately, little is known about the secreted αKlotho isoform, since available antibodies cannot discriminate s-KL from the KL1 domain cleaved from the transmembrane isoform. This study shows, for the first time, that the klotho transcript produced by alternative splicing generates a stable protein (70 kDa), and that in contrast to the transmembrane Klotho isoform, it is ten times more abundant in the brain than in the kidney suggesting that the two isoforms may have different functions. We also studied whether klotho expression in the CNS was influenced by aging, Alzheimer's disease (AD), or a healthy lifestyle, such as voluntary moderate continuous exercise. We observed a strong correlation between high expression levels of the two klotho transcripts and the healthy status of the animals. Expression of Klotho in brain areas decayed more rapidly in the 3xTg-AD model of AD than in healthy animals, whilst moderate continuous exercise in adulthood prevents the decline in expression of both klotho transcripts. PMID:26599613

  5. Regulation of cellular transport by klotho protein.

    Science.gov (United States)

    Sopjani, Mentor; Rinnerthaler, Mark; Almilaji, Ahmad; Ahmeti, Salih; Dermaku-Sopjani, Miribane

    2014-01-01

    The antiaging protein of Klotho is a transmembrane protein mainly expressed in the kidney, parathyroid glands and choroid plexus of the brain. The Klotho protein exists in two forms, a full-length membrane form and a soluble secreted form. The extracellular domain of Klotho can be enzymatically cleaved off and released into the systemic circulation where it acts as β-glucuronidase and a hormone. Soluble Klotho can be found in the blood, cerebrospinal fluid, and the urine of mammals. Klotho deficiency results in early appearance of multiple age-related disorders and premature death, whereas overexpression of Klotho exerts the opposite effect. Klotho may influence cellular transport processes across the cell membrane by inhibiting calcitriol (1,25(OH) (2)D(3)), formation or by directly affecting transporter proteins, including ion channels, carriers and pumps. Accordingly, Klotho protein is a powerful regulator of transport mechanisms across the cell membrane. Klotho regulates diverse calcium and potassium ion channels, as well as several carriers including the Na(+)-coupled excitatory amino acid transporters EAAT3 and EAAT4, the Na(+)-coupled phosphate cotransporters, NaPi-IIa and NaPi-IIb, and a Na(+)/K(+)-ATPase. All those cellular transport regulations contribute in the aging suppressor role of Klotho. Future studies will help to determine if the Klotho protein regulates cell-surface expression of other transport proteins and is affecting underlying mechanisms.

  6. Klotho-Dependent Cellular Transport Regulation.

    Science.gov (United States)

    Sopjani, M; Dërmaku-Sopjani, M

    2016-01-01

    Klotho is a transmembrane protein that in humans is encoded by the hKL gene. This protein is known to have aging suppressor effects and is predominantly expressed in the distal convoluted tubule of the kidney, parathyroid glands, and choroid plexus of the brain. The Klotho protein exists in both full-length membrane form and a soluble secreted form, which exerts numerous distinct functions. The extracellular domain of Klotho can be enzymatically cleaved off and released into the systemic circulation where it functions as β-glucuronidase and a hormone. Soluble Klotho is a multifunction protein present in the biological fluids including blood, urine, and cerebrospinal fluid of mammals. Klotho deficiency leads to multiple organ failure accompanied by early appearance of multiple age-related disorders and early death, whereas overexpression of Klotho results in the opposite effects. Klotho, an enzyme and hormone, has been reported to participate in the regulation of cellular transport processes across the plasma membrane either indirectly through inhibiting calcitriol (1,25(OH)2D3) formation or other mechanism, or by directly affecting transporter proteins, including ion channels, cellular carriers, and Na(+)/K(+)-ATPase. Accordingly, Klotho protein serves as a powerful regulator of cellular transport across the plasma membrane. Importantly, Klotho-dependent cellular transport regulation implies stimulatory or inhibitory effects. Klotho has been shown to play a key role in the regulation of multiple calcium and potassium ion channels, and various cellular carriers including the Na(+)-coupled cotransporters such as NaPi-IIa, NaPi-IIb, EAAT3, and EAAT4, CreaT1 as well as Na(+)/K(+)-ATPase. These regulations are parts of the antiaging function of Klotho, which will be discussing throughout this chapter. Clearly, further experimental efforts are required to investigate the effect of Klotho on other transport proteins and underlying molecular mechanisms by which Klotho

  7. Parathyroid-Specific Deletion of Klotho Unravels a Novel Calcineurin-Dependent FGF23 Signaling Pathway That Regulates PTH Secretion

    Science.gov (United States)

    Olauson, Hannes; Lindberg, Karolina; Amin, Risul; Sato, Tadatoshi; Jia, Ting; Goetz, Regina; Mohammadi, Moosa; Andersson, Göran; Lanske, Beate; Larsson, Tobias E.

    2013-01-01

    Klotho acts as a co-receptor for and dictates tissue specificity of circulating FGF23. FGF23 inhibits PTH secretion, and reduced Klotho abundance is considered a pathogenic factor in renal secondary hyperparathyroidism. To dissect the role of parathyroid gland resident Klotho in health and disease, we generated mice with a parathyroid-specific Klotho deletion (PTH-KL−/−). PTH-KL−/− mice had a normal gross phenotype and survival; normal serum PTH and calcium; unaltered expression of the PTH gene in parathyroid tissue; and preserved PTH response and sensitivity to acute changes in serum calcium. Their PTH response to intravenous FGF23 delivery or renal failure did not differ compared to their wild-type littermates despite disrupted FGF23-induced activation of the MAPK/ERK pathway. Importantly, calcineurin-NFAT signaling, defined by increased MCIP1 level and nuclear localization of NFATC2, was constitutively activated in PTH-KL−/− mice. Treatment with the calcineurin-inhibitor cyclosporine A abolished FGF23-mediated PTH suppression in PTH-KL−/− mice whereas wild-type mice remained responsive. Similar results were observed in thyro-parathyroid explants ex vivo. Collectively, we present genetic and functional evidence for a novel, Klotho-independent, calcineurin-mediated FGF23 signaling pathway in parathyroid glands that mediates suppression of PTH. The presence of Klotho-independent FGF23 effects in a Klotho-expressing target organ represents a paradigm shift in the conceptualization of FGF23 endocrine action. PMID:24348262

  8. Effects of Metformin on Serum Levels of Secreted Klotho and Leptin in PCOS Women

    Directory of Open Access Journals (Sweden)

    Savadali Saifi Novashnag

    2016-07-01

    Patients’ weights showed some decline. Fasting plasma glucose levels and insulin resistance decreased significantly (p<0.01. Hormonal assays indicated significant decrease in leptin and insulin levels and rise in Klotho levels. BMIs did not change meaningfully. Measurements of leptin and klotho levels showed a decrease in mean leptin levels from 34.74 to 28.41 ng/l and the level of klotho increased from 4.01 to 5.43 ng/l. Conclusion: This study showed that metformin treatment can cause a rise in klotho and a decrease in leptin levels without considerable effects on the weights of women with PCOS. Probably, leptin exerts its physiological effects in low concentrations while klotho in contrast acts physiologically in higher concentrations.

  9. Incretin secretion: direct mechanisms

    DEFF Research Database (Denmark)

    Balk-Møller, Emilie; Holst, Jens Juul; Kuhre, Rune Ehrenreich

    2014-01-01

    The incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) are secreted from gastro-intestinal K- and L-cells, respectively, and play an important role in post-prandial blood glucose regulation. They do this by direct stimulation of the pancreatic β......-cell, accounting for some 25-70% of postprandial insulin secretion in healthy subjects. In patients with type 2 diabetes (T2D, however, this effect is greatly reduced or lost due to a combination of severely impaired or eliminated insulinotrophic effect of GIP and reduced meal stimulated GLP-1 secretion...... enzyme responsible for incretin degradation (dipeptidyl peptidase-4) is inhibited (drugs are already on the market) while the secretion of endogenous GLP-1 secretion is stimulated at the same time may prove particularly rewarding. In this section we review current knowledge on the mechanisms for direct...

  10. Klotho: a humeral mediator in CSF and plasma that influences longevity and susceptibility to multiple complex disorders, including depression.

    Science.gov (United States)

    Pavlatou, M G; Remaley, A T; Gold, P W

    2016-08-30

    Klotho is a hormone secreted into human cerebrospinal fluid (CSF), plasma and urine that promotes longevity and influences the onset of several premature senescent phenotypes in mice and humans, including atherosclerosis, cardiovascular disease, stroke and osteoporosis. Preliminary studies also suggest that Klotho possesses tumor suppressor properties. Klotho's roles in these phenomena were first suggested by studies demonstrating that a defect in the Klotho gene in mice results in a significant decrease in lifespan. The Klotho-deficient mouse dies prematurely at 8-9 weeks of age. At 4-5 weeks of age, a syndrome resembling human ageing emerges consisting of atherosclerosis, osteoporosis, cognitive disturbances and alterations of hippocampal architecture. Several deficits in Klotho-deficient mice are likely to contribute to these phenomena. These include an inability to defend against oxidative stress in the central nervous system and periphery, decreased capacity to generate nitric oxide to sustain normal endothelial reactivity, defective Klotho-related mediation of glycosylation and ion channel regulation, increased insulin/insulin-like growth factor signaling and a disturbed calcium and phosphate homeostasis accompanied by altered vitamin D levels and ectopic calcification. Identifying the mechanisms by which Klotho influences multiple important pathways is an emerging field in human biology that will contribute significantly to understanding basic physiologic processes and targets for the treatment of complex diseases. Because many of the phenomena seen in Klotho-deficient mice occur in depressive illness, major depression and bipolar disorder represent illnesses potentially associated with Klotho dysregulation. Klotho's presence in CSF, blood and urine should facilitate its study in clinical populations.

  11. Incretin secretion: direct mechanisms

    DEFF Research Database (Denmark)

    Balk-Møller, Emilie; Holst, Jens Juul; Kuhre, Rune Ehrenreich

    2014-01-01

    enzyme responsible for incretin degradation (dipeptidyl peptidase-4) is inhibited (drugs are already on the market) while the secretion of endogenous GLP-1 secretion is stimulated at the same time may prove particularly rewarding. In this section we review current knowledge on the mechanisms for direct......The incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) are secreted from gastro-intestinal K- and L-cells, respectively, and play an important role in post-prandial blood glucose regulation. They do this by direct stimulation of the pancreatic β....... This suggests that the therapeutic potential of GIP for the treatment for T2D is limited, whereas GLP-1 based treatments have been on the market since 2005. Research is now pursuing novel approaches to utilize the effects of GLP-1 for T2D treatment. A combinatorial approach by which the activity of the major...

  12. Periodontitis aggravated pancreatic β-cell dysfunction in diabetic mice through interleukin-12 regulation on Klotho.

    Science.gov (United States)

    Liu, Yihua; Zhang, Qiuli

    2016-05-01

    Recent studies have shown that periodontitis can contribute to adipose tissue inflammation and subsequent systemic insulin resistance in the obese rat model. However, the related inflammatory mechanism is not yet clear. The present study aims to investigate the effects of periodontitis on the function of pancreatic β-cells with pro-inflammatory cytokines-related immune mechanism in a mouse model. C57BL/6-db/db and inbred C57BL/6 mice were chosen here to establish a mouse model with periodontitis, which was induced by ligatures for 8 weeks. Glucose-stimulated insulin secretion was introduced to evaluate the function of pancreatic islets and β-cells. Serum levels of pro-inflammatory cytokines and Klotho were also measured, and the correlation between immunostimulation and Klotho level was deeply investigated in vitro. Pancreatic β-cell failure, with insulin resistance, was observed in db/db mice, while periodontitis could aggravate β-cell dysfunction-related features. Serum levels of interleukin (IL)-12 and Klotho showed a negatively synergistic change, whereas the expression of Klotho was also inhibited under IL-12 treatment in MIN6 β-cells or isolated islets. Furthermore, IL-12-induced immune stimulation and also decreased insulin secretion were proven to be reversed by Klotho overexpression. Periodontitis aggravated pancreatic β-cell failure in diabetic mice. Further in vitro studies showed IL-12 regulation on Klotho, while Klotho also acted as an inhibitor on IL-12, indicating the potential of Klotho for preserving pancreatic β-cell function in diabetes.

  13. Increased parathyroid expression of klotho in uremic rats

    DEFF Research Database (Denmark)

    Hofman-Bang, J.; Martuseviciene, G.; Santini, M.A.

    2010-01-01

    /6 nephrectomy rat model of secondary hyperparathyroidism. Parathyroid klotho gene expression and protein were significantly increased in severely uremic hyperphosphatemic rats, but not affected by moderate uremia and normal serum phosphorus. Calcitriol suppressed klotho gene and protein expression in severe...... secondary hyperparathyroidism, despite a further increase in plasma phosphate. Both FGFR1 IIIC and Na+/K+-ATPase gene expression were significantly elevated in severe secondary hyperparathyroidism. Parathyroid gland klotho expression and the plasma calcium ion concentration were inversely correlated. Thus......, our study suggests that klotho may act as a positive regulator of PTH expression and secretion in secondary hyperparathyroidism....

  14. Klotho: a humeral mediator in CSF and plasma that influences longevity and susceptibility to multiple complex disorders, including depression

    OpenAIRE

    Pavlatou, M G; Remaley, A T; Gold, P W

    2016-01-01

    Klotho is a hormone secreted into human cerebrospinal fluid (CSF), plasma and urine that promotes longevity and influences the onset of several premature senescent phenotypes in mice and humans, including atherosclerosis, cardiovascular disease, stroke and osteoporosis. Preliminary studies also suggest that Klotho possesses tumor suppressor properties. Klotho's roles in these phenomena were first suggested by studies demonstrating that a defect in the Klotho gene in mice results in a signific...

  15. Increased parathyroid expression of klotho in uremic rats.

    Science.gov (United States)

    Hofman-Bang, Jacob; Martuseviciene, Giedre; Santini, Martin A; Olgaard, Klaus; Lewin, Ewa

    2010-12-01

    Klotho is a protein of significant importance for mineral homeostasis. It helps to increase parathyroid hormone (PTH) secretion and in the trafficking of Na+/K+-ATPase to the cell membrane; however, it is also a cofactor for fibroblast growth factor (FGF)-23 to interact with its receptor, FGFR1 IIIC, resulting in decreased PTH secretion. Studies on the regulation of parathyroid klotho expression in uremia have provided varying results. To help resolve this, we measured klotho expression in the parathyroid and its response to severe uremia, hyperphosphatemia, and calcitriol treatment in the 5/6 nephrectomy rat model of secondary hyperparathyroidism. Parathyroid klotho gene expression and protein were significantly increased in severely uremic hyperphosphatemic rats, but not affected by moderate uremia and normal serum phosphorus. Calcitriol suppressed klotho gene and protein expression in severe secondary hyperparathyroidism, despite a further increase in plasma phosphate. Both FGFR1 IIIC and Na+/K+-ATPase gene expression were significantly elevated in severe secondary hyperparathyroidism. Parathyroid gland klotho expression and the plasma calcium ion concentration were inversely correlated. Thus, our study suggests that klotho may act as a positive regulator of PTH expression and secretion in secondary hyperparathyroidism.

  16. Soluble klotho and mortality: The Ludwigshafen Risk and Cardiovascular Health Study

    NARCIS (Netherlands)

    Brandenburg, V.M.; Kleber, M.E.; Vervloet, M.G.; Larsson, T.E.; Tomaschitz, A.; Pilz, S.; Stojakovic, T.; Delgado, G.; Grammer, T.B.; Marx, N.; Maerz, W.; Scharnagl, H.

    2015-01-01

    Background: Experimental evidence suggests that soluble klotho (s-klotho), a co-receptor for fibroblast growth factor 23 (FGF23), may modulate cardiovascular risk through multiple mechanisms. However, the predictive value of s-klotho in patients remains unclear. Therefore, the present study examined

  17. Serum klotho protein levels and their correlations with the progression of type 2 diabetes mellitus.

    Science.gov (United States)

    Nie, Fang; Wu, Dongming; Du, Hongfei; Yang, Xianggui; Yang, Min; Pang, Xueli; Xu, Ying

    2017-03-01

    To investigate the associations of serum α-Klotho and β-Klotho levels with type 2 diabetes mellitus (T2DM) progression. We evaluated 106 healthy controls and 261 cases of T2DM with or without diabetic complications (range: 45-84years). Serum α-Klotho and β-Klotho levels were analyzed using enzyme-linked immunosorbent assays. Compared to the healthy controls, α-Klotho and β-Klotho levels were significantly lower among patients with T2DM and with or without diabetic complications (Pdiabetes, and the positive correlation of α-Klotho and β-Klotho levels indicates that they might have similar mechanisms in T2DM. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Multiple sclerosis influences on the augmentation of serum Klotho concentration

    DEFF Research Database (Denmark)

    Ahmadi, Mona; Aleagha, Mohammad Sajad Emami; Harirchian, Mohammad Hossein

    2016-01-01

    We have already shown that the concentration of secreted form of Klotho decreases in the cerebrospinal fluid of patients with relapsing–remitting multiple sclerosis (RRMS). The current study aimed at assessing possible changes in the serum Klotho concentration of MS patients. Participants involved......, demographic and clinical data (e.g. gender, age, duration of disease and expanded disability status scale) were obtained. Serum Klotho concentration was measured using ELISA method. The results showed no statistically meaningful difference between new cases of RRMS (585.56 pg/ml ± 153.99) and control group...

  19. Wound healing delays in α-Klotho-deficient mice that have skin appearance similar to that in aged humans - Study of delayed wound healing mechanism.

    Science.gov (United States)

    Yamauchi, Makoto; Hirohashi, Yoshihiko; Torigoe, Toshihiko; Matsumoto, Yoshitaka; Yamashita, Ken; Kayama, Musashi; Sato, Noriyuki; Yotsuyanagi, Takatoshi

    2016-05-13

    Skin atrophy and delayed wound healing are observed in aged humans; however, the molecular mechanism are still elusive. The aim of this study was to analyze the molecular mechanisms of delayed wound healing by aging using α-Klotho-deficient (kl/kl) mice, which have phenotypes similar to those of aged humans. The kl/kl mice showed delayed wound healing and impaired granulation formation compared with those in wild-type (WT) mice. The skin graft experiments revealed that delayed wound healing depends on humoral factors, but not on kl/kl skin tissue. The mRNA expression levels of cytokines related to acute inflammation including IL-1β, IL-6 and TNF-α were higher in wound lesions of kl/kl mice compared with the levels in WT mice by RT-PCR analysis. LPS-induced TNF-α production model using spleen cells revealed that TNF-α production was significantly increased in the presence of FGF23. Thus, higher levels of FGF23 in kl/kl mouse may have a role to increase TNF-α production in would lesion independently of α-Klotho protein, and impair granulation formation and delay wound healing. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. The anti-aging protein Klotho is induced by GABA therapy and exerts protective and stimulatory effects on pancreatic beta cells.

    Science.gov (United States)

    Prud'homme, Gérald J; Glinka, Yelena; Kurt, Merve; Liu, Wenjuan; Wang, Qinghua

    2017-12-02

    Systemic gamma-aminobutyric acid (GABA) therapy prevents or ameliorates type 1 diabetes (T1D), by suppressing autoimmune responses and stimulating pancreatic beta cells. In beta cells, it increases insulin secretion, prevents apoptosis, and induces regeneration. It is unclear how GABA mediates these effects. We hypothesized that Klotho is involved. It is a multi-functional protein expressed in the kidneys, brain, pancreatic beta cells, other tissues, and is cell-bound or soluble. Klotho knockout mice display accelerated aging, and in humans Klotho circulating levels decline with age, renal disease and diabetes. Here, we report that GABA markedly increased circulating levels of Klotho in streptozotocin (STZ)-induced diabetes. GABA also increased Klotho in the islet of Langerhans of normal mice, as well as the islets and kidneys of STZ-treated mice. In vitro, GABA stimulated production and secretion of Klotho by human islet cells. Knockdown (KD) of Klotho with siRNA in INS-1E insulinoma cells abrogated the protective effects of GABA against STZ toxicity. Following KD, soluble Klotho reversed the effects of Klotho deficiency. In human islet cells soluble Klotho protected against cell death, and stimulated proliferation and insulin secretion. NF-κB activation triggers beta-cell apoptosis, and both GABA and Klotho suppress this pathway. We found Klotho KD augmented NF-κB p65 expression, and abrogated the ability of GABA to block NF-κB activation. This is the first report that GABAergic stimulation increases Klotho expression. Klotho protected and stimulated beta cells and lack of Klotho (KD) was reversed by soluble Klotho. These findings have important implications for the treatment of T1D. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  1. Secretion management in the mechanically ventilated patient.

    Science.gov (United States)

    Branson, Richard D

    2007-10-01

    Secretion management in the mechanically ventilated patient includes routine methods for maintaining mucociliary function, as well as techniques for secretion removal. Humidification, mobilization of the patient, and airway suctioning are all routine procedures for managing secretions in the ventilated patient. Early ambulation of the post-surgical patient and routine turning of the ventilated patient are common secretion-management techniques that have little supporting evidence of efficacy. Humidification is a standard of care and a requisite for secretion management. Both active and passive humidification can be used. The humidifier selected and the level of humidification required depend on the patient's condition and the expected duration of intubation. In patients with thick, copious secretions, heated humidification is superior to a heat and moisture exchanger. Airway suctioning is the most important secretion removal technique. Open-circuit and closed-circuit suctioning have similar efficacy. Instilling saline prior to suctioning, to thin the secretions or stimulate a cough, is not supported by the literature. Adequate humidification and as-needed suctioning are the foundation of secretion management in the mechanically ventilated patient. Intermittent therapy for secretion removal includes techniques either to simulate a cough, to mechanically loosen secretions, or both. Patient positioning for secretion drainage is also widely used. Percussion and postural drainage have been widely employed for mechanically ventilated patients but have not been shown to reduce ventilator-associated pneumonia or atelectasis. Manual hyperinflation and insufflation-exsufflation, which attempt to improve secretion removal by simulating a cough, have been described in mechanically ventilated patients, but neither has been studied sufficiently to support routine use. Continuous lateral rotation with a specialized bed reduces atelectasis in some patients, but has not been shown

  2. Klotho and the Growth Hormone/Insulin-Like Growth Factor 1 Axis: Novel Insights into Complex Interactions.

    Science.gov (United States)

    Rubinek, T; Modan-Moses, D

    2016-01-01

    The growth hormone (GH)/insulin-like growth factor (IGF)-1 axis is pivotal for many metabolic functions, including proper development and growth of bones, skeletal muscles, and adipose tissue. Defects in the axis' activity during childhood result in growth abnormalities, while increased secretion of GH from the pituitary results in acromegaly. In order to keep narrow physiologic concentration, GH and IGF-1 secretion and activity are tightly regulated by hypothalamic, pituitary, endocrine, paracrine, and autocrine factors. Klotho was first discovered as an aging-suppressor gene. Mice that do not express klotho die prematurely with multiple symptoms of aging, several of them are also characteristic of decreased GH/IGF-1 axis activity. Klotho is highly expressed in the brain, the kidney, and parathyroid and pituitary glands, but can also serve as a circulating hormone by its shedding, forming soluble klotho that can be detected in blood, cerebrospinal fluid, and urine. Several lines of evidence suggest an association between klotho levels and activity of the GH/IGF-1 axis: the GH-secreting cells in the anterior pituitary of klotho-deficient mice are hypotrophic; klotho levels are altered in subjects with pathologies of the GH/IGF-1 axis; and accumulating data indicate that klotho is a direct regulator of GH secretion. Thus, klotho seems to be a new player in the intricate regulation of the GH/IGF-1 axis. © 2016 Elsevier Inc. All rights reserved.

  3. Klotho regulates CA1 hippocampal synaptic plasticity.

    Science.gov (United States)

    Li, Qin; Vo, Hai T; Wang, Jing; Fox-Quick, Stephanie; Dobrunz, Lynn E; King, Gwendalyn D

    2017-04-07

    Global klotho overexpression extends lifespan while global klotho-deficiency shortens it. As well, klotho protein manipulations inversely regulate cognitive function. Mice without klotho develop rapid onset cognitive impairment before they are 2months old. Meanwhile, adult mice overexpressing klotho show enhanced cognitive function, particularly in hippocampal-dependent tasks. The cognitive enhancing effects of klotho extend to humans with a klotho polymorphism that increases circulating klotho and executive function. To affect cognitive function, klotho could act in or on the synapse to modulate synaptic transmission or plasticity. However, it is not yet known if klotho is located at synapses, and little is known about its effects on synaptic function. To test this, we fractionated hippocampi and detected klotho expression in both pre and post-synaptic compartments. We find that loss of klotho enhances both pre and post-synaptic measures of CA1 hippocampal synaptic plasticity at 5weeks of age. However, a rapid loss of synaptic enhancement occurs such that by 7weeks, when mice are cognitively impaired, there is no difference from wild-type controls. Klotho overexpressing mice show no early life effects on synaptic plasticity, but decreased CA1 hippocampal long-term potentiation was measured at 6months of age. Together these data suggest that klotho affects cognition, at least in part, by regulating hippocampal synaptic plasticity. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  4. Rhein reverses Klotho repression via promoter demethylation and protects against kidney and bone injuries in mice with chronic kidney disease.

    Science.gov (United States)

    Zhang, Qin; Liu, Lin; Lin, Wenjun; Yin, Shasha; Duan, Aiping; Liu, Zhihong; Cao, Wangsen

    2017-01-01

    Rhein is an anthraquinone compound isolated from the medicinal plant rhubarb and mainly used in the clinical treatment of diabetic nephropathy. Rhein exhibits various renoprotective functions, but the underlying mechanisms are not fully determined. However, its renoprotective properties recapitulate the role of Klotho, a renal-specific antiaging protein critical for maintaining kidney homeostasis. Here we explored the connections between rhein renoprotection and Klotho in a mouse model of adenine-induced chronic kidney disease. In addition to being an impressive Klotho upregulator, rhein remarkably reversed renal Klotho deficiency in adenine-treated mice. This effect was associated with significant improvement in disturbed serum biochemistry, profibrogenic protein expression, and kidney and bone damage. Further investigation of the molecular basis of Klotho loss revealed that these kidneys displayed marked inductions of DNA methyltransferase DNMT1/DNMT3a and Klotho promoter hypermethylation, whereas rhein treatment effectively corrected these alterations. The renal protective effects of rhein were largely abolished when Klotho was knocked-down by RNA interferences, suggesting that rhein reversal of Klotho deficiency is essential for its renoprotective actions. Thus, our study clarifies how rhein regulation of Klotho expression contributes to its renoprotection and brings new insights into Klotho-targeted strategy for the treatment of kidney diseases of various etiologies. Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

  5. Testosterone increases renal anti-aging klotho gene expression via the androgen receptor-mediated pathway.

    Science.gov (United States)

    Hsu, Shih-Che; Huang, Shih-Ming; Lin, Shih-Hua; Ka, Shuk-Man; Chen, Ann; Shih, Meng-Fu; Hsu, Yu-Juei

    2014-12-01

    Gender is known to be associated with longevity and oestrogen administration induced longevity-associated gene expression is one of the potential mechanisms underlying the benefits of oestrogen on lifespan, whereas the role of testosterone in the regulation of longevity-associated gene expressions remains largely unclear. The klotho gene, predominantly expressed in the kidney, has recently been discovered to be an aging suppressor gene. In the present study, we investigated the regulatory effects of testosterone on renal klotho gene expression in vivo and in vitro. In testosterone-administered mouse kidney and NRK-52E cells, increased klotho expression was accompanied by the up-regulation of the nuclear androgen receptor (AR). Overexpression of AR enhanced the expression of klotho mRNA and protein. Conversely, testosterone-induced klotho expression was attenuated in the presence of flutamide, an AR antagonist. A reporter assay and a chromatin immunoprecipitation (ChIP) assay demonstrated that AR directly binds to the klotho promoter via androgen response elements (AREs) which reconfirmed its importance for AR binding via the element mutation. In summary, our study demonstrates that testosterone up-regulates anti-aging klotho together with AR expression in the kidney in vivo and in vitro by recruiting AR on to the AREs of the klotho promoter.

  6. αKlotho and Chronic Kidney Disease

    Science.gov (United States)

    Neyra, J.A.; Hu, M.C.

    2017-01-01

    Alpha-KlothoKlotho) protein is encoded by the gene, Klotho, and functions as a coreceptor for endocrine fibroblast growth factor-23. The extracellular domain of αKlotho is cleaved by secretases and released into the circulation where it is called soluble αKlotho. Soluble αKlotho in the circulation starts to decline in chronic kidney disease (CKD) stage 2 and urinary αKlotho in even earlier CKD stage 1. Therefore soluble αKlotho is an early and sensitive marker of decline in kidney function. Preclinical data from numerous animal experiments support αKlotho deficiency as a pathogenic factor for CKD progression and extrarenal CKD complications including cardiac and vascular disease, hyperparathyroidism, and disturbed mineral metabolism. αKlotho deficiency induces cell senescence and renders cells susceptible to apoptosis induced by a variety of cellular insults including oxidative stress. αKlotho deficiency also leads to defective autophagy and angiogenesis and promotes fibrosis in the kidney and heart. Most importantly, prevention of αKlotho decline, upregulation of endogenous αKlotho production, or direct supplementation of soluble αKlotho are all associated with attenuation of renal fibrosis, retardation of CKD progression, improvement of mineral metabolism, amelioration of cardiac function and morphometry, and alleviation of vascular calcification in CKD. Therefore in rodents, αKlotho is not only a diagnostic and prognostic marker for CKD but the enhancement of endogenous or supplement of exogenous αKlotho are promising therapeutic strategies to prevent, retard, and decrease the comorbidity burden of CKD. PMID:27125746

  7. FGF23 Regulates Bone Mineralization in a 1,25(OH)2 D3 and Klotho-Independent Manner.

    Science.gov (United States)

    Murali, Sathish Kumar; Roschger, Paul; Zeitz, Ute; Klaushofer, Klaus; Andrukhova, Olena; Erben, Reinhold G

    2016-01-01

    Fibroblast growth factor-23 (Fgf23) is a bone-derived hormone, suppressing phosphate reabsorption and vitamin D hormone (1,25(OH)2 D3 ) production in the kidney. It has long been an enigma why lack of Fgf23 or of Klotho, the coreceptor for Fgf23, leads to severe impairment in bone mineralization despite the presence of hypercalcemia and hyperphosphatemia. Using Fgf23(-/-) or Klotho(-/-) mice together with compound mutant mice lacking both Fgf23 or Klotho and a functioning vitamin D receptor, we show that in Klotho(-/-) mice the mineralization defect is solely driven by 1,25(OH)2 D3 -induced upregulation of the mineralization-inhibiting molecules osteopontin and pyrophosphate in bone. In Fgf23(-/-) mice, the mineralization defect has two components, a 1,25(OH)2 D3 -driven component similar to Klotho(-/-) mice and a component driven by lack of Fgf23, causing additional accumulation of osteopontin. We found that FGF23 regulates osteopontin secretion indirectly by suppressing alkaline phosphatase transcription and phosphate production in osteoblastic cells, acting through FGF receptor-3 in a Klotho-independent manner. Hence, FGF23 secreted from osteocytes may form an autocrine/paracrine feedback loop for the local fine-tuning of bone mineralization. © 2015 American Society for Bone and Mineral Research.

  8. Local Klotho enhances neuronal progenitor proliferation in the adult hippocampus.

    Science.gov (United States)

    Salech, Felipe; Varela-Nallar, Lorena; Arredondo, Sebastián B; Bustamante, Daniel B; Andaur, Gabriela A; Cisneros, Rodrigo; Ponce, Daniela P; Ayala, Patricia; Inestrosa, Nibaldo C; Valdés, José L; Behrens, María I; Couve, Andrés

    2017-12-30

    Klotho is an aging-related protein associated with hippocampal cognitive performance in mammals. Klotho regulates progenitor cell proliferation in non-neuronal tissues, but its role in adult hippocampal neurogenesis (AHN) has not been explored. Klotho expression in the adult mouse hippocampus was examined by immunofluorescence and PCR. AHN was evaluated in the hippocampus of klotho knock-out mice (KO), klotho KO/vitamin D-receptor mutant mice, and in a model of local klotho hippocampal knockdown. The recombinant Klotho effect on proliferation was measured in mouse-derived hippocampal neural progenitor cells. Hippocampal-dependent memory was assessed by a dry-land version of the Morris water maze. Klotho was expressed in the granular cell layer of the adult Dentate Gyrus. AHN was increased in klotho KO mice, but not in klotho KO/vitamin D-receptor mutant mice. Inversely, local downregulation of hippocampal Klotho diminished AHN. Recombinant Klotho increased the proliferation rate of neural progenitors. Downregulation of hippocampal Klotho correlated with a decreased performance in hippocampal dependent memory. These results suggest that Klotho directly participates in regulating AHN. Our observations indicate that Klotho promotes proliferation, AHN and hippocampal dependent cognition. Increased neurogenesis in klotho KO mice may be secondary to the activation of other pathways altered in the model, such as vitamin D. © The Author(s) 2017. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. Humidification and secretion volume in mechanically ventilated patients.

    Science.gov (United States)

    Solomita, Mario; Palmer, Lucy B; Daroowalla, Feroza; Liu, Jeffrey; Miller, Dori; LeBlanc, Deniese S; Smaldone, Gerald C

    2009-10-01

    To determine potential effects of humidification on the volume of airway secretions in mechanically ventilated patients. Water vapor delivery from devices providing non-heated-wire humidification, heated-wire humidification, and heat and moisture exchanger (HME) were quantified on the bench. Then, patients requiring 24-hour mechanical ventilation were exposed sequentially to each of these humidification devices, and secretions were removed and measured by suctioning every hour during the last 4 hours of the 24-hour study period. In vitro water vapor delivery was greater using non-heated-wire humidification, compared to heated-wire humidification and HME. In vivo, a total of 9 patients were studied. Secretion volume following humidification by non-heated-wire humidification was significantly greater than for heated-wire humidification and HME (P=.004). The volume of secretions appeared to be linked to humidification, as greater water vapor delivery measured in vitro was associated with greater secretion volume in vivo.

  10. Longevity factor klotho and chronic psychological stress.

    Science.gov (United States)

    Prather, A A; Epel, E S; Arenander, J; Broestl, L; Garay, B I; Wang, D; Dubal, D B

    2015-06-16

    Chronic psychological stress is associated with accelerated aging and premature morbidity and mortality; however, the biology linking chronic psychological stress and its maladaptive effects remains largely unknown. Klotho is a pleiotropic hormone that regulates the aging process and promotes better brain and body health. Whether klotho is linked to psychosocial stress or its negative impact in humans has not been investigated. To address this gap, we recruited 178 healthy women who were either chronically high-stress maternal caregivers for a child with autism spectrum disorder (n = 90) or low-stress control mothers of a typically developing child (n = 88). We found that women under high chronic stress displayed significantly lower levels of the longevity hormone klotho compared with low-stress controls (t(176) = 2.92, P = 0.004; d = 0.44), and the decrease among those under high stress was age-dependent. In addition, high-stress caregivers who reported more depressive symptoms displayed even lower klotho levels compared with low-stress participants. These findings provide the first evidence that klotho levels are sensitive to psychosocial stressors and raise the possibility that klotho may serve as a novel biological link connecting stress, depression and risk for accelerated disease development. Furthermore, these findings have important implications for understanding the plasticity of the aging process and may represent a therapeutic target for mitigating the deleterious effects of chronic psychological stress on health and well-being.

  11. Klotho: its various functions and association with sickle cell disease subphenotypes

    Directory of Open Access Journals (Sweden)

    Ana Paula Almeida de Souza Pacheco

    2014-12-01

    Full Text Available The Klotho protein, whose gene has predominant renal expression, acts in the control of serum phosphorus and 1,25-dihydroxyvitamin D3 and regulates the function of ion channels. It also participates in the mechanism of protection against oxidative stress and acts on the vascular endothelium by inducing the production of nitric oxide. Mutations that reflect defects in the Klotho gene expression may be implicated in the onset of osteonecrosis, priapism, and leg ulcers in patients with sickle cell disease, as a result of oxidative stress and endothelial impairment, important factors in the development and severity of this disease. Previous reports regarding the association of Klotho single nucleotide polymorphisms with sickle cell disease subphenotypes have found that these polymorphisms are important to identify genetic markers of risk in these individuals and allow early and more effective therapeutic intervention.

  12. Shedding of klotho by ADAMs in the kidney

    NARCIS (Netherlands)

    van Loon, Ellen P. M.; Pulskens, Wilco P.; van der Hagen, Eline A. E.; Lavrijsen, Marla; Vervloet, Marc G.; van Goor, Harry; Bindels, Rene J. M.; Hoenderop, Joost G. J.

    2015-01-01

    The anti-aging gene klotho plays an important role in Ca2+ and phosphate homeostasis. Membrane-bound klotho is an essential coreceptor for fibroblast growth factor-23 and can be cleaved by proteases, including a disintegrin and metalloproteinase (ADAM) 10 and ADAM17. Cleavage of klotho occurs at a

  13. A Novel Mechanism for Protein Delivery by the Type 3 Secretion System for Extracellularly Secreted Proteins.

    Science.gov (United States)

    Tejeda-Dominguez, Farid; Huerta-Cantillo, Jazmin; Chavez-Dueñas, Lucia; Navarro-Garcia, Fernando

    2017-03-28

    The type 3 secretion system (T3SS) is essential for bacterial virulence through delivering effector proteins directly into the host cytosol. Here, we identified an alternative delivery mechanism of virulence factors mediated by the T3SS, which consists of the association of extracellularly secreted proteins from bacteria with the T3SS to gain access to the host cytosol. Both EspC, a protein secreted as an enteropathogenic Escherichia coli (EPEC) autotransporter, and YopH, a protein detected on the surface of Yersinia , require a functional T3SS for host cell internalization; here we provide biophysical and molecular evidence to support the concept of the EspC translocation mechanism, which requires (i) an interaction between EspA and an EspC middle segment, (ii) an EspC translocation motif (21 residues that are shared with the YopH translocation motif), (iii) increases in the association and dissociation rates of EspC mediated by EspA interacting with EspD, and (iv) an interaction of EspC with the EspD/EspB translocon pore. Interestingly, this novel mechanism does not exclude the injection model (i.e., EspF) operating through the T3SS conduit; therefore, T3SS can be functioning as an internal conduit or as an external railway, which can be used to reach the translocator pore, and this mechanism appears to be conserved among different T3SS-dependent pathogens. IMPORTANCE The type 3 secretion system is essential for injection of virulence factors, which are delivered directly into the cytosol of the host cells for usurping and subverting host processes. Recent studies have shown that these effectors proteins indeed travel inside an "injectisome" conduit through a single step of translocation by connecting the bacterium and host cell cytoplasms. However, all findings are not compatible with this model. For example, both YopH, a protein detected on the surface of Yersinia , and EspC, an autotransporter protein secreted by enteropathogenic E. coli , require a

  14. Influence of Flavonoids on Mechanism of Modulation of Insulin Secretion.

    Science.gov (United States)

    Soares, Juliana Mikaelly Dias; Pereira Leal, Ana Ediléia Barbosa; Silva, Juliane Cabral; Almeida, Jackson R G S; de Oliveira, Helinando Pequeno

    2017-01-01

    The development of alternatives for insulin secretion control in vivo or in vitro represents an important aspect to be investigated. In this direction, natural products have been progressively explored with this aim. In particular, flavonoids are potential candidates to act as insulin secretagogue. To study the influence of flavonoid on overall modulation mechanisms of insulin secretion. The research was conducted in the following databases and platforms: PubMed, Scopus, ISI Web of Knowledge, SciELO, LILACS, and ScienceDirect, and the MeSH terms used for the search were flavonoids, flavones, islets of Langerhans, and insulin-secreting cells. Twelve articles were included and represent the basis of discussion on mechanisms of insulin secretion of flavonoids. Papers in ISI Web of Knowledge were in number of 1, Scopus 44, PubMed 264, ScienceDirect 511, and no papers from LILACS and SciELO databases. According to the literature, the majority of flavonoid subclasses can modulate insulin secretion through several pathways, in an indication that corresponding molecule is a potential candidate for active materials to be applied in the treatment of diabetes. The action of natural products on insulin secretion represents an important investigation topic due to their importance in the diabetes controlIn addition to their typical antioxidant properties, flavonoids contribute to the insulin secretionThe modulation of insulin secretion is induced by flavonoids according to different mechanisms. Abbreviations used: K ATP channels: ATP-sensitive K + channels, GLUT4: Glucose transporter 4, ERK1/2: Extracellular signal-regulated protein kinases 1 and 2, L-VDCCs: L-type voltage-dependent Ca +2 channels, GLUT1: Glucose transporter 1, AMPK: Adenosine monophosphate-activated protein kinase, PTP1B: Protein tyrosine phosphatase 1B, GLUT2: Glucose transporter 2, cAMP: Cyclic adenosine monophosphate, PKA: Protein kinase A, PTK: Protein tyrosine kinase, CaMK II: Ca 2+ /calmodulin

  15. Upregulation of KCNQ1/KCNE1 K+ channels by Klotho.

    Science.gov (United States)

    Almilaji, Ahmad; Pakladok, Tatsiana; Muñoz, Carlos; Elvira, Bernat; Sopjani, Mentor; Lang, Florian

    2014-01-01

    Klotho is a transmembrane protein expressed primarily in kidney, parathyroid gland, and choroid plexus. The extracellular domain could be cleaved off and released into the systemic circulation. Klotho is in part effective as β-glucuronidase regulating protein stability in the cell membrane. Klotho is a major determinant of aging and life span.Overexpression of Klotho increases and Klotho deficiency decreases life span. Klotho deficiency may further result in hearing loss and cardiac arrhythmia. The present study explored whether Klotho modifies activity and protein abundance of KCNQ1/KCNE1, a K(+) channel required for proper hearing and cardiac repolarization. To this end, cRNA encoding KCNQ1/KCNE1 was injected in Xenopus oocytes with or without additional injection of cRNA encoding Klotho. KCNQ1/KCNE1 expressing oocytes were treated with human recombinant Klotho protein (30 ng/mL) for 24 h. Moreover, oocytes which express both KCNQ1/KCNE1 and Klotho were treated with 10 μM DSA L (D-saccharic acid-1,4-lactone), a β-glucuronidase inhibitor. The KCNQ1/KCNE1 depolarization-induced current (I(Ks)) was determined utilizing dual electrode voltage clamp, while KCNQ1/KCNE1 protein abundance in the cell membrane was visualized utilizing specific antibody binding and quantified by chemiluminescence. KCNQ1/KCNE1 channel activity and KCNQ1/KCNE1 protein abundance were upregulated by coexpression of Klotho. The effect was mimicked by treatment with human recombinant Klotho protein (30 ng/mL) and inhibited by DSA L (10 μM). In conclusion, Klotho upregulates KCNQ1/KCNE1 channel activity by “mainly” enhancing channel protein abundance in the plasma cell membrane, an effect at least partially mediated through the β-glucuronidase activity of Klotho protein.

  16. Parathyroid Klotho and FGF-receptor 1 expression decline with renal function in hyperparathyroid patients with chronic kidney disease and kidney transplant recipients.

    Science.gov (United States)

    Krajisnik, Tijana; Olauson, Hannes; Mirza, Majd A I; Hellman, Per; Akerström, Göran; Westin, Gunnar; Larsson, Tobias E; Björklund, Peyman

    2010-11-01

    Current studies suggest that short-term exposure of parathyroid glands to fibroblast growth factor 23 (FGF23) reduces parathyroid hormone secretion. However, patients with chronic kidney disease (CKD) develop secondary hyperparathyroidism despite high levels of serum FGF23, indicating a parathyroid FGF23 'resistance'. Here we analyzed the expression of the FGF23 receptors Klotho and FGF receptor 1 (FGFR1) in 88 hyperplastic parathyroid glands from 31 patients with CKD (including 21 renal allograft recipients), and their regulation in isolated bovine and human hyperplastic parathyroid cells. Glandular expression was variable, yet the Klotho and FGFR1 mRNA levels declined in parallel with the decreasing glomerular filtration rate, significantly decreasing over CKD stages. We found no association between the expression of Klotho, FGFR1, and the proliferation marker Ki67. In vitro treatment of bovine cells with FGF23 or calcium reduced the Klotho level, whereas active vitamin D(3) compounds increased its expression. Phosphate and parathyroid hormone had no effect. Treatment had less impact on Klotho in cultured human cells than in the bovine healthy cell model, whereas FGFR1 expression was induced in the hyperplastic cells. Thus parathyroid Klotho and FGFR1 decrease with declining renal function, possibly because of alterations in mineral metabolism related to the failing kidney. This could explain the observed parathyroid resistance to FGF23 in late CKD.

  17. Upregulation of Klotho potentially inhibits pulmonary vascular remodeling by blocking the activation of the Wnt signaling pathway in rats with PM2.5-induced pulmonary arterial hypertension.

    Science.gov (United States)

    Cong, Lu-Hong; Du, Shi-Yu; Wu, Yi-Na; Liu, Ying; Li, Tao; Wang, Hui; Li, Gang; Duan, Jun

    2018-01-30

    We evaluated the effects of Klotho on pulmonary vascular remodeling and cell proliferation and apoptosis in rat models with PM2.5-induced pulmonary arterial hypertension (PAH) via the Wnt signaling pathway. After establishing rat models of PM2.5-induced PAH, these Sprague-Dawley male rats were randomized into control and model groups. Cells extracted from the model rats were sub-categorized into different groups. Activation of Wnt/β-catenin signaling transcription factor was detected by a TOPFlash/FOPFlash assay. A serial of experiment was conducted to identify the mechanism of Klotho on PHA via the Wnt signaling pathway. VEGF levels and PaCO 2 content were higher in the model group, while PaO 2, NO 2 - /NO 3 - content and Klotho level was lower compared to the control group. In comparison to the control group, the model group had decreased Klotho and Bax levels, and elevated Wnt-1, β-catenin, bcl-2, survivin, and PCNA expression, VEGF, IL-6, TNF-α, TNF-β1, and bFGF levels, as well as the percentage of pulmonary artery ring contraction. The Klotho vector, DKK-1 and DKK-1 + Klotho vector groups exhibited reduced cell proliferation, luciferase activity, and the expression of Wnt-1, β-catenin, bcl-2, survivin, and PCNA, as well as shortened S phase compared with the blank and NC groups. Compared with the Klotho vector and DKK-1 groups, the DKK-1 + Klotho vector groups had reduced cell proliferation, luciferase activity, and the expression of Wnt-1, β-catenin, bcl-2, survivin, and PCNA, as well as a shortened S phase. Conclusively, Klotho inhibits pulmonary vascular remodeling by inactivation of Wnt signaling pathway. © 2018 Wiley Periodicals, Inc.

  18. Eicosapentaenoic acid prevents arterial calcification in klotho mutant mice.

    Science.gov (United States)

    Nakamura, Kazufumi; Miura, Daiji; Saito, Yukihiro; Yunoki, Kei; Koyama, Yasushi; Satoh, Minoru; Kondo, Megumi; Osawa, Kazuhiro; Hatipoglu, Omer F; Miyoshi, Toru; Yoshida, Masashi; Morita, Hiroshi; Ito, Hiroshi

    2017-01-01

    The klotho gene was identified as an "aging-suppressor" gene that accelerates arterial calcification when disrupted. Serum and vascular klotho levels are reduced in patients with chronic kidney disease, and the reduced levels are associated with arterial calcification. Intake of eicosapentaenoic acid (EPA), an n-3 fatty acid, reduces the risk of fatal coronary artery disease. However, the effects of EPA on arterial calcification have not been fully elucidated. The aim of this study was to determine the effect of EPA on arterial calcification in klotho mutant mice. Four-week-old klotho mutant mice and wild-type (WT) mice were given a diet containing 5% EPA (EPA food, klotho and WT: n = 12, each) or not containing EPA (control food, klotho and WT: n = 12, each) for 4 weeks. Calcium volume scores of thoracic and abdominal aortas assessed by computed tomography were significantly elevated in klotho mice after 4 weeks of control food, but they were not elevated in klotho mice after EPA food or in WT mice. Serum levels of EPA and resolvin E1, an active metabolite of EPA, in EPA food-fed mice were significantly increased compared to those in control food-fed mice. An oxidative stress PCR array followed by quantitative PCR revealed that NADPH oxidase-4 (NOX4), an enzyme that generates superoxide, gene expression was up-regulated in arterial smooth muscle cells (SMCs) of klotho mice. Activity of NOX was also significantly higher in SMCs of klotho mice than in those of WT mice. EPA decreased expression levels of the NOX4 gene and NOX activity. GPR120, a receptor of n-3 fatty acids, gene knockdown by siRNA canceled effects of EPA on NOX4 gene expression and NOX activity in arterial SMCs of klotho mice. EPA prevents arterial calcification together with reduction of NOX gene expression and activity via GPR120 in klotho mutant mice.

  19. Role of Klotho in Osteoporosis and Renal Osteodystrophy

    Science.gov (United States)

    2015-10-01

    which is assumed to be a key role of Klotho in proximal tubules and put further stress on renal phosphate handling. Both Kap-KL and Kap-WT mice were...in the proximal tubules is crucial for vitamin D regulation. 8     We demonstrate that proximal tubular Klotho is important for renal phosphate...mineral metabolism, which are evidenced by the proximal tubules specific deletion of Klotho (4/16/15) • In Vivo Role of Klotho in the Renal Proximal

  20. Soluble α-klotho and its relation to kidney function and fibroblast growth factor-23

    DEFF Research Database (Denmark)

    Scholze, Alexandra; Liu, Ying; Pedersen, Lise

    2014-01-01

    CONTEXT: Relations between fibroblast growth factor-23 (FGF-23), soluble α-klotho (s-α-klotho), and kidney function in chronic kidney disease (CKD) are still unclear. Especially the role of s-α-klotho requires further study. OBJECTIVES: Our objectives were to analyze the relation of s-α-klotho to......CONTEXT: Relations between fibroblast growth factor-23 (FGF-23), soluble α-klotho (s-α-klotho), and kidney function in chronic kidney disease (CKD) are still unclear. Especially the role of s-α-klotho requires further study. OBJECTIVES: Our objectives were to analyze the relation of s...

  1. The mechanism of biliary lipid secretion and its defects

    NARCIS (Netherlands)

    Elferink, R. P.; Groen, A. K.

    1999-01-01

    Biliary lipid secretion is an important physiological event; not only for the disposal of cholesterol from the body, but also for the protection of cells lining the biliary tree against bile salts. Insight into the (patho)physiological role of biliary lipid secretion has been recently expanded

  2. Klotho Protein: Its Role in Aging and Central Nervous System Pathology.

    Science.gov (United States)

    Boksha, I S; Prokhorova, T A; Savushkina, O K; Tereshkina, E B

    2017-09-01

    This review is devoted to Klotho protein and recent evidences for its functions in the brain. Information on transcriptional regulation of the klotho gene and posttranslational modifications of the protein resulting in multiple forms of Klotho is reviewed. Evidence is summarized that Klotho regulates the activity of protein factors, enzymes, and receptors, including data suggesting the importance of its glycosidase activity. Effects of Klotho on components of the glutamatergic neurotransmitter system, signal cascades involving protein kinases and protein phosphorylation, as well as oligodendrocyte differentiation and myelination are discussed. A possible contribution is proposed for Klotho levels in the development of central nervous system pathologies including mental disorders.

  3. Role of Klotho in Osteoporosis and Renal Osteodystrophy

    Science.gov (United States)

    2014-10-01

    Klotho knockout mice, which present with hypercalcemia, hyperphosphatemia, hypoparathyroidism as well as high levels of serum calcitriol and serum...Issue 12 | e1003975 just like their wild-type littermates did. Its severity as well as changes in other markers of mineral metabolism was similar among...Is the Principal Organ Mediating Klotho Effects Karolina Lindberg,* Risul Amin,* Orson W. Moe,† Ming-Chang Hu,† Reinhold G. Erben,‡ Annika Östman

  4. Reduction of Oxidative Stress in Chronic Kidney Disease Does Not Increase Circulating α-Klotho Concentrations

    NARCIS (Netherlands)

    Adema, Aaltje Y.; van Ittersum, Frans J.; Hoenderop, Joost G.; de Borst, Martin H.; Nanayakkara, Prabath W.; ter Wee, Piet M.; Heijboer, Annemieke C.; Vervloet, Marc G.; Bindels, R.; Hoenderop, J. G.; de Borst, M. H.; Hillebrands, J. L.; Navis, G. J.; ter Wee, P. M.; Vervloet, M. G.

    2016-01-01

    The CKD-associated decline in soluble α-Klotho levels is considered detrimental. Some in vitro and in vivo animal studies have shown that anti-oxidant therapy can upregulate the expression of α-Klotho in the kidney. We examined the effect of anti-oxidant therapy on α-Klotho concentrations in a

  5. Reduction of Oxidative Stress in Chronic Kidney Disease Does Not Increase Circulating alpha-Klotho Concentrations

    NARCIS (Netherlands)

    Adema, Aaltje Y.; van Ittersum, Frans J.; Hoenderop, Joost G.; de Borst, Martin H.; Nanayakkara, Prabath W.; Ter Wee, Piet M.; Heijboer, Annemieke C.; Vervloet, Marc G.

    2016-01-01

    The CKD-associated decline in soluble alpha-Klotho levels is considered detrimental. Some in vitro and in vivo animal studies have shown that anti-oxidant therapy can upregulate the expression of alpha-Klotho in the kidney. We examined the effect of anti-oxidant therapy on alpha-Klotho

  6. Reduction of Oxidative Stress in Chronic Kidney Disease Does Not Increase Circulating alpha-Klotho Concentrations.

    NARCIS (Netherlands)

    Adema, A.Y.; Ittersum, F.J. van; Hoenderop, J.G.J.; Borst, M.H. de; Nanayakkara, P.W.; Wee, P.M. Ter; Heijboer, A.C.; Vervloet, M.G.

    2016-01-01

    The CKD-associated decline in soluble alpha-Klotho levels is considered detrimental. Some in vitro and in vivo animal studies have shown that anti-oxidant therapy can upregulate the expression of alpha-Klotho in the kidney. We examined the effect of anti-oxidant therapy on alpha-Klotho

  7. Effects of thoracic squeezing on airway secretion removal in mechanically ventilated patients

    Directory of Open Access Journals (Sweden)

    Farkhondeh Yousefnia-Darzi

    2016-01-01

    Conclusions: According to the study findings, endotracheal suction with thoracic squeezing on expiration helps airway secretion discharge more than suction alone in patients on mechanical ventilators and can be used as an effective method.

  8. Deletion of PTH rescues skeletal abnormalities and high osteopontin levels in Klotho-/- mice.

    Directory of Open Access Journals (Sweden)

    Quan Yuan

    Full Text Available Maintenance of normal mineral ion homeostasis is crucial for many biological activities, including proper mineralization of the skeleton. Parathyroid hormone (PTH, Klotho, and FGF23 have been shown to act as key regulators of serum calcium and phosphate homeostasis through a complex feedback mechanism. The phenotypes of Fgf23(-/- and Klotho(-/- (Kl(-/- mice are very similar and include hypercalcemia, hyperphosphatemia, hypervitaminosis D, suppressed PTH levels, and severe osteomalacia/osteoidosis. We recently reported that complete ablation of PTH from Fgf23(-/- mice ameliorated the phenotype in Fgf23(-/-/PTH(-/- mice by suppressing serum vitamin D and calcium levels. The severe osteomalacia in Fgf23(-/- mice, however, persisted, suggesting that a different mechanism is responsible for this mineralization defect. In the current study, we demonstrate that deletion of PTH from Kl(-/- (Kl(-/-/PTH(-/- or DKO mice corrects the abnormal skeletal phenotype. Bone turnover markers are restored to wild-type levels; and, more importantly, the skeletal mineralization defect is completely rescued in Kl(-/-/PTH(-/- mice. Interestingly, the correction of the osteomalacia is accompanied by a reduction in the high levels of osteopontin (Opn in bone and serum. Such a reduction in Opn levels could not be observed in Fgf23(-/-/PTH(-/- mice, and these mice showed sustained osteomalacia. This significant in vivo finding is corroborated by in vitro studies using calvarial osteoblast cultures that show normalized Opn expression and rescued mineralization in Kl(-/-/PTH(-/- mice. Moreover, continuous PTH infusion of Kl(-/- mice significantly increased Opn levels and osteoid volume, and decreased trabecular bone volume. In summary, our results demonstrate for the first time that PTH directly impacts the mineralization disorders and skeletal deformities of Kl(-/-, but not of Fgf23(-/- mice, possibly by regulating Opn expression. These are significant new perceptions into

  9. Upregulation of the Creatine Transporter Slc6A8 by Klotho

    Directory of Open Access Journals (Sweden)

    Ahmad Almilaji

    2014-11-01

    Full Text Available Background/Aims: The transmembrane Klotho protein contributes to inhibition of 1,25(OH2D3 formation. The extracellular domain of Klotho protein could function as an enzyme with e.g. β-glucuronidase activity, be cleaved off and be released into blood and cerebrospinal fluid. Klotho regulates several cellular transporters. Klotho protein deficiency accelerates the appearance of age related disorders including neurodegeneration and muscle wasting and eventually leads to premature death. The main site of Klotho protein expression is the kidney. Klotho protein is also appreciably expressed in other tissues including chorioid plexus. The present study explored the effect of Klotho protein on the creatine transporter CreaT (Slc6A8, which participates in the maintenance of neuronal function and survival. Methods: To this end cRNA encoding Slc6A8 was injected into Xenopus oocytes with and without additional injection of cRNA encoding Klotho protein. Creatine transporter CreaT (Slc6A8 activity was estimated from creatine induced current determined by two-electrode voltage-clamp. Results: Coexpression of Klotho protein significantly increased creatine-induced current in Slc6A8 expressing Xenopus oocytes. Coexpression of Klotho protein delayed the decline of creatine induced current following inhibition of carrier insertion into the cell membrane by brefeldin A (5 µM. The increase of creatine induced current by coexpression of Klotho protein in Slc6A8 expressing Xenopus oocytes was reversed by β-glucuronidase inhibitor (DSAL. Similarly, treatment of Slc6A8 expressing Xenopus oocytes with recombinant human alpha Klotho protein significantly increased creatine induced current. Conclusion: Klotho protein up-regulates the activity of creatine transporter CreaT (Slc6A8 by stabilizing the carrier protein in the cell membrane, an effect requiring β-glucuronidase activity of Klotho protein.

  10. Plasma FGF21 concentrations, adipose fibroblast growth factor receptor-1 and β-klotho expression decrease with fasting in northern elephant seals.

    Science.gov (United States)

    Suzuki, Miwa; Lee, Andrew Y; Vázquez-Medina, José Pablo; Viscarra, Jose A; Crocker, Daniel E; Ortiz, Rudy M

    2015-05-15

    Fibroblast growth factor (FGF)-21 is secreted from the liver, pancreas, and adipose in response to prolonged fasting/starvation to facilitate lipid and glucose metabolism. Northern elephant seals naturally fast for several months, maintaining a relatively elevated metabolic rate to satisfy their energetic requirements. Thus, to better understand the impact of prolonged food deprivation on FGF21-associated changes, we analyzed the expression of FGF21, FGF receptor-1 (FGFR1), β-klotho (KLB; a co-activator of FGFR) in adipose, and plasma FGF21, glucose and 3-hydroxybutyrate in fasted elephant seal pups. Expression of FGFR1 and KLB mRNA decreased 98% and 43%, respectively, with fasting duration. While the 80% decrease in mean adipose FGF21 mRNA expression with fasting did not reach statistical significance, it paralleled the 39% decrease in plasma FGF21 concentrations suggesting that FGF21 is suppressed with fasting in elephant seals. Data demonstrate an atypical response of FGF21 to prolonged fasting in a mammal suggesting that FGF21-mediated mechanisms have evolved differentially in elephant seals. Furthermore, the typical fasting-induced, FGF21-mediated actions such as the inhibition of lipolysis in adipose may not be required in elephant seals as part of a naturally adapted mechanism to support their unique metabolic demands during prolonged fasting. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Soluble αKlotho as a candidate for the biomarker of aging.

    Science.gov (United States)

    Koyama, Daisuke; Sato, Yu; Aizawa, Masato; Maki, Takumi; Kurosawa, Masaki; Kuro-o, Makoto; Furukawa, Yusuke

    2015-11-27

    Although the Klotho gene has been recognized as an aging-suppressor gene, the significance of its soluble product, soluble αKlotho (sKlotho), in aging remains to be elucidated. To address this issue, we conducted a single-centered cross-sectional study in a region with a high prevalence of aging. We compared sKlotho levels with the patient characteristics from medical records and laboratory measurements, including fibroblast growth factor 23 (FGF23), intact parathyroid hormone, activated vitamin D3 and factors associated with mineral bone metabolism, in 52 outpatients with a mean age of 78.2 years. Serum sKlotho levels significantly decreased with age, but were not associated with the stage of chronic kidney disease (CKD). Serum FGF23 levels increased as CKD stages advanced, but were not associated with aging. Univariate analyses revealed that sKlotho levels positively correlated with glomerular filtration rate, and negatively with age and serum levels of FGF23 and phosphorus. In a multivariable linear regression analysis, sKlotho significantly correlated with aging and lower FGF23 levels. Only osteoporosis affected sKlotho and FGF23 levels among the various complications and patient status including medication. In summary, serum sKlotho levels inversely correlated with age and FGF23, and were significantly reduced in patients with osteoporosis. sKlotho may serve as a biomarker of aging independent of renal function. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Cerebral klotho protein as a humoral factor for maintenance of baroreflex.

    Science.gov (United States)

    Chen, L-J; Cheng, M-F; Ku, P-M; Cheng, J-T

    2015-02-01

    The klotho protein produced by the choroid plexus is known as a humoral factor in central nervous system. Many hormones affecting the baroreflex sensitivity have been introduced in the brain. However, role of klotho in the baroreflex sensitivity is still unknown. Recently, mutations in the klotho gene have been linked to cardiovascular diseases in both animals and human subjects. Also, silencing of brain klotho has been reported to enhance cold-induced elevation of blood pressure. Thus, we investigated the role of klotho in maintenance of central cardiovascular reflex sensitivity. Male Wistar Kyoto (WKY) rats and spontaneously hypertensive rats (SHRs) were used. Either klotho shRNA or scramble shRNA was also ICV-infused into the brains of WKY rats to investigate the role of klotho in brain. Recombinant klotho or rat IgG was infused into the cerebral paraventricle (ICV) of SHRs for further understanding the role of klotho in hypertension. The baroreflex sensitivity was detected using the challenge with a depressor dose of sodium nitroprusside (SNP, 50 μg/kg) or with a pressor dose of phenylephrine (PE, 8 μg/kg). We found that silencing of klotho expression in the brain decreased the baroreflex sensitivity in WKY rats. Also, modulation of the blood pressure for one week altered the cardiovascular homeostasis and resulted in an increased expression of klotho in medulla oblongata. Moreover, the baroreflex sensitivity was restored in SHRs that received recombinant klotho through ICV brain. Thus, klotho is involved in the maintenance of baroreflex sensitivity in the brain. © Georg Thieme Verlag KG Stuttgart · New York.

  13. Klotho & Activin A in kidney injury Plasma Klotho is maintained in unilateral obstruction despite no upregulation of Klotho biosynthesis in contralateral kidney

    DEFF Research Database (Denmark)

    Nordholm, Anders; Mace, Maria L; Gravesen, Eva

    2018-01-01

    In a new paradigm of etiology related to Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD) kidney injury may cause induction of factors in the injured kidney that are released into the circulation and thereby initiate and maintain renal fibrosis and CKD-MBD. Klotho is believed to amelior......In a new paradigm of etiology related to Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD) kidney injury may cause induction of factors in the injured kidney that are released into the circulation and thereby initiate and maintain renal fibrosis and CKD-MBD. Klotho is believed...... to ameliorate renal fibrosis and CKD-MBD, while ActivinA might have detrimental effects. The unilateral ureter obstruction (UUO) model is used here to examine this concept by investigating early changes related to renal fibrosis in obstructed kidney, untouched contralateral kidney and vasculature, which might...

  14. Mechanisms of biliary lipid secretion and their role in lipid homeostasis

    NARCIS (Netherlands)

    Oude Elferink, R. P.; Groen, A. K.

    2000-01-01

    Bile secretion serves different important functions. First, it is one of the main mechanisms for the disposition of many endogenous and exogenous amphipatic compounds, including drugs, toxins, and waste products. Second, it supplies bile salts to the intestine, which is of crucial importance for the

  15. Alpha-adrenergic stimulation of corticotropin secretion by a specific central mechanism in man.

    Science.gov (United States)

    Al-Damluji, S; Perry, L; Tomlin, S; Bouloux, P; Grossman, A; Rees, L H; Besser, G M

    1987-01-01

    In a double-blind study in normal subjects, methoxamine, a highly selective agonist at alpha-1-adrenoceptors, significantly increased circulating ACTH and cortisol. The stimulant effect of methoxamine on cortisol secretion was dose dependent in the range 3.5-7 micrograms/kg/min, was abolished by concomitant administration of the strong alpha-1-adrenergic (and weak H1) antagonist thymoxamine but unaffected by the antihistamine, chlorpheniramine. In order to test whether the action of methoxamine on ACTH secretion was exerted centrally or peripherally, the effects of norepinephrine (NE), an alpha-1-agonist that does not cross the blood-brain barrier, were studied. Doses of NE (1-12 micrograms/min) that increased systolic blood pressure by amounts similar to the changes produced by methoxamine, did not result in any rise in plasma cortisol in normal subjects. The effect of methoxamine, which is more lipid soluble than NE, on plasma ACTH and cortisol, appears to be exerted on the CNS and not at the pituitary or via nonspecific peripheral mechanisms. In addition to its water solubility, NE differs from methoxamine in its beta-1-, beta-2- and alpha-2-agonist actions. However, prenalterol (2 mg) and salbutamol (250 micrograms), respectively beta-1- and beta-2-adrenergic agonist drugs, had no effect on the secretion of ACTH or cortisol and the alpha-2-antagonist yohimbine in an effective dose did not unmask a stimulant effect of intravenous NE on plasma cortisol. At high infusion rates, NE significantly inhibited cortisol secretion. Stimulation of central alpha-1-adrenergic mechanisms results in secretion of ACTH in man, presumably by increased release of a corticotropin-releasing factor.

  16. The mechanism of fluid secretion in the rabbit pancreas studied by means of various inhibitors.

    Science.gov (United States)

    Kuijpers, G A; Van Nooy, I G; De Pont, J J; Bonting, S L

    1984-12-05

    In order to increase our understanding of the mechanism of pancreatic fluid secretion we have studied the effects of various transport inhibitors on this process in the isolated rabbit pancreas. In this preparation, a high rate of unstimulated fluid secretion occurs, which probably originates from the ductular cells. Inhibitory are ouabain, furosemide, bumetanide, piretanide, 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid (SITS) and acetazolamide, with their half-inhibitory concentrations: 2 X 10(-6) M (ouabain), 1.3 X 10(-3) M (furosemide), 2.2 X 10(-3) M (bumetanide and piretanide) and 1.4 X 10(-4) M (SITS). With acetazolamide a maximal inhibition of only 20% is found at 10(-3) M. Amiloride (10(-3) M) has no effect on pancreatic fluid secretion. The inhibitory effects on HCO-3 output are always larger and those on Cl- output lower than those on fluid secretion. The results suggest that the ouabain-sensitive (Na+ + K+)-ATPase system provides the energy for a Na+-gradient-driven Cl--HCO-3-exchange transport system, sensitive to the loop diuretics furosemide, bumetanide and piretanide and to SITS. This system would drive the transcellular transport of HCO-3 and secondarily that of cations, Cl- and water.

  17. The Possible Mechanisms of the Impaired Insulin Secretion in Hypothyroid Rats

    Science.gov (United States)

    Godini, Aliashraf; Ghasemi, Asghar

    2015-01-01

    Although the insulin secretion deficit in hypothyroid male rats has been documented, the underling mechanisms of the effect of hypothyroidism on insulin secretion are not clear. Isolated islets of the PTU-induced hypothyroid and control rats were exposed to glibenclamide, acetylcholine, and nifedipine in the presence of glucose concentrations of 2.8 or 8.3 and 16.7 mmol/L. Glucokinase and hexokinase specific activity, glucokinase content, and glucose transporter 2 protein expression were also determined in the isolated islets. Isolated islets from the hypothyroid rats showed a defect in insulin secretion in response to high glucose. In the presence of glibenclamide or acetylcholine, the isolated islets from the hypothyroid and control rats stimulated by glucose concentration of 16.7 mmol/L secreted similar amounts of insulin. In the presence of glucose concentrations of 8.3 mmol/L and 16.7 mmol/L, nifedipine was able to diminish insulin secretion from isolated islets of both groups, indicating that probably the defect may not arise from L type calcium channels or the steps beyond depolarization or the elements involved in the acetylcoline signaling pathway. Glucokinase content and hexokinase specific activity were also the same in the control and hypothyroid groups. On the other hand, glucokinase specific activity and glucose transporter 2 protein expression were significantly (phypothyroid rats (6.50 ± 0.46 mU/min/mg protein and 0.55 ± 0.09 arbitrary unit) compared to the controls (10.93 ± 0.83 mU/min/mg protein and 0.98 ± 0.07 arbitrary unit) respectively. In conclusion, the results of this study indicated that hypothyroidism reduced insulin secretion from isolated pancreatic islets, which confirms the finding of the previous studies; in addition, the insulin secretion deficit observed in hypothyroid rats may arise from the abnormalities in some parts of the glucose sensor apparatus of the pancreatic islets including glucokinase activity and glucose

  18. The Possible Mechanisms of the Impaired Insulin Secretion in Hypothyroid Rats.

    Directory of Open Access Journals (Sweden)

    Aliashraf Godini

    Full Text Available Although the insulin secretion deficit in hypothyroid male rats has been documented, the underling mechanisms of the effect of hypothyroidism on insulin secretion are not clear. Isolated islets of the PTU-induced hypothyroid and control rats were exposed to glibenclamide, acetylcholine, and nifedipine in the presence of glucose concentrations of 2.8 or 8.3 and 16.7 mmol/L. Glucokinase and hexokinase specific activity, glucokinase content, and glucose transporter 2 protein expression were also determined in the isolated islets. Isolated islets from the hypothyroid rats showed a defect in insulin secretion in response to high glucose. In the presence of glibenclamide or acetylcholine, the isolated islets from the hypothyroid and control rats stimulated by glucose concentration of 16.7 mmol/L secreted similar amounts of insulin. In the presence of glucose concentrations of 8.3 mmol/L and 16.7 mmol/L, nifedipine was able to diminish insulin secretion from isolated islets of both groups, indicating that probably the defect may not arise from L type calcium channels or the steps beyond depolarization or the elements involved in the acetylcoline signaling pathway. Glucokinase content and hexokinase specific activity were also the same in the control and hypothyroid groups. On the other hand, glucokinase specific activity and glucose transporter 2 protein expression were significantly (p<0.001 and p<0.01 respectively lower in the islets isolated from the hypothyroid rats (6.50 ± 0.46 mU/min/mg protein and 0.55 ± 0.09 arbitrary unit compared to the controls (10.93 ± 0.83 mU/min/mg protein and 0.98 ± 0.07 arbitrary unit respectively. In conclusion, the results of this study indicated that hypothyroidism reduced insulin secretion from isolated pancreatic islets, which confirms the finding of the previous studies; in addition, the insulin secretion deficit observed in hypothyroid rats may arise from the abnormalities in some parts of the glucose sensor

  19. A host defense mechanism involving CFTR-mediated bicarbonate secretion in bacterial prostatitis.

    Directory of Open Access Journals (Sweden)

    Chen Xie

    Full Text Available BACKGROUND: Prostatitis is associated with a characteristic increase in prostatic fluid pH; however, the underlying mechanism and its physiological significance have not been elucidated. METHODOLOGY/PRINCIPAL FINDINGS: In this study a primary culture of rat prostatic epithelial cells and a rat prostatitis model were used. Here we reported the involvement of CFTR, a cAMP-activated anion channel conducting both Cl(- and HCO(3(-, in mediating prostate HCO(3(- secretion and its possible role in bacterial killing. Upon Escherichia coli (E. coli-LPS challenge, the expression of CFTR and carbonic anhydrase II (CA II, along with several pro-inflammatory cytokines was up-regulated in the primary culture of rat prostate epithelial cells. Inhibiting CFTR function in vitro or in vivo resulted in reduced bacterial killing by prostate epithelial cells or the prostate. High HCO(3(- content (>50 mM, rather than alkaline pH, was found to be responsible for bacterial killing. The direct action of HCO(3(- on bacterial killing was confirmed by its ability to increase cAMP production and suppress bacterial initiation factors in E. coli. The relevance of the CFTR-mediated HCO(3(- secretion in humans was demonstrated by the upregulated expression of CFTR and CAII in human prostatitis tissues. CONCLUSIONS/SIGNIFICANCE: The CFTR and its mediated HCO(3(- secretion may be up-regulated in prostatitis as a host defense mechanism.

  20. Serum Klotho (but not haplotypes associate with the post-myocardial infarction status of older adults

    Directory of Open Access Journals (Sweden)

    Roberta S. Paula

    Full Text Available OBJECTIVES: The number of deaths from vascular diseases is incredibly high worldwide, and reliable markers for major events are still needed. The current cross-sectional study investigated the association of Klotho haplotypes and Klotho serum levels with classic risk factors and a clinical history of vascular events. METHODS: Clinical, anthropometric, biochemical and nutritional assessments were conducted with 168 older adults, complemented by genotyping (rs9536314 and rs9527025 and the detection of serum Klotho (ELISA. RESULTS: Klotho levels and haplotypes did not associate with most classic risk factors for vascular events, including markers such as C-reactive protein and homocysteine. A positive association was only found between Klotho levels and the previous occurrence of a myocardial infarction by both correlational (p=0.006 and variance analyses (p<0.001, and these associations were independent of the context. CONCLUSION: Our results suggest that serum Klotho is higher in individuals with a clinical history of myocardial infarction but not with a history of coronary artery disease or stroke. None of the Klotho haplotypes were associated with the variables investigated herein.

  1. Klotho gene silencing promotes pathology in the mdx mouse model of Duchenne muscular dystrophy

    Science.gov (United States)

    Wehling-Henricks, Michelle; Li, Zhenzhi; Lindsey, Catherine; Wang, Ying; Welc, Steven S.; Ramos, Julian N.; Khanlou, Négar; Kuro-o, Makoto; Tidball, James G.

    2016-01-01

    Duchenne muscular dystrophy (DMD) is a lethal muscle disease involving progressive loss of muscle regenerative capacity and increased fibrosis. We tested whether epigenetic silencing of the klotho gene occurs in the mdx mouse model of DMD and whether klotho silencing is an important feature of the disease. Our findings show that klotho undergoes muscle-specific silencing at the acute onset of mdx pathology. Klotho experiences increased methylation of CpG sites in its promoter region, which is associated with gene silencing, and increases in a repressive histone mark, H3K9me2. Expression of a klotho transgene in mdx mice restored their longevity, reduced muscle wasting, improved function and greatly increased the pool of muscle-resident stem cells required for regeneration. Reductions of fibrosis in late, progressive stages of the mdx pathology achieved by transgene expression were paralleled by reduced expression of Wnt target genes (axin-2), transforming growth factor-beta (TGF-β1) and collagens types 1 and 3, indicating that Klotho inhibition of the profibrotic Wnt/TGFβ axis underlies its anti-fibrotic effect in aging, dystrophic muscle. Thus, epigenetic silencing of klotho during muscular dystrophy contributes substantially to lost regenerative capacity and increased fibrosis of dystrophic muscle during late progressive stages of the disease. PMID:27154199

  2. 25-Hydroxyvitamin D3 1-Alpha-Hydroxylase-Dependent Stimulation of Renal Klotho Expression by Spironolactone

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    Ioana Alesutan

    2013-11-01

    Full Text Available Background: Klotho, a transmembrane protein, protease and hormone mainly expressed in kidney, is required for the suppression of 1,25(OH2D3-generating 25-hydroxyvitamin D3 1-alpha-hydroxylase (Cyp27b1 by FGF23. Conversely, 1,25(OH2D3 stimulates, by activating the vitamin D3 receptor (Vdr, the expression of klotho, thus establishing a negative feedback loop. Klotho protects against renal and vascular injury. Klotho deficiency accelerates aging and early death, effects at least partially due to excessive formation of 1,25(OH2D3 and subsequent hyperphosphatemia. Klotho expression is inhibited by aldosterone. The present study explored the interaction of aldosterone and DOCA as well as the moderately selective mineralocorticoid receptor antagonist spironolactone on klotho expression. Methods: mRNA levels were determined utilizing quantitative RT-PCR in human embryonic kidney cells (HEK293 or in renal tissues from mice without or with prior mineralocorticoid (aldosterone or DOCA and/or spironolactone treatment. In HEK293 cells, protein levels were determined by western blotting. The experiments in HEK293 cells were performed without or with silencing of CYP27B1, of vitamin D3 receptor (VDR or of mineralocorticoid receptor (NR3C2. Results: In HEK293 cells aldosterone and in mice DOCA significantly decreased KLOTHO gene expression, effects opposed by spironolactone treatment. Spironolactone treatment alone significantly increased KLOTHO and CYP27B1 transcript levels in HEK293 cells (24 hours and mice (8 hours or 5 days. Moreover, spironolactone significantly increased klotho and CYP27B1 protein levels in HEK293 cells (48 hours. Reduced NR3C2 expression following silencing did not significantly affect KLOTHO and CYP27B1 transcript levels in presence or absence of spironolactone. Silencing of CYP27B1 and VDR significantly blunted the stimulating effect of spironolactone on KLOTHO mRNA levels in HEK293 cells. Conclusion: Besides blocking the effects of

  3. Differential regulation of renal Klotho and FGFR1 in normal and uremic rats.

    Science.gov (United States)

    Muñoz-Castañeda, Juan R; Herencia, Carmen; Pendón-Ruiz de Mier, Maria Victoria; Rodriguez-Ortiz, Maria Encarnación; Diaz-Tocados, Juan M; Vergara, Noemi; Martínez-Moreno, Julio M; Salmerón, Maria Dolores; Richards, William G; Felsenfeld, Arnold; Kuro-O, Makoto; Almadén, Yolanda; Rodríguez, Mariano

    2017-09-01

    In renal failure, hyperphosphatemia occurs despite a marked elevation in serum fibroblast growth factor (FGF)-23. Abnormal regulation of the FGFR1-Klotho receptor complex may cause a resistance to the phosphaturic action of FGF23. The purpose of the present study was to investigate the regulation of renal Klotho and FGF receptor (FEFR)-1 in healthy and uremic rats induced by 5/6 nephrectomy. In normal rats, the infusion of rat recombinant FGF23 enhanced phosphaturia and increased renal FGFR1 expression; however, Klotho expression was reduced. Uremic rats on a high-phosphate (HP) diet presented hyperphosphatemia with marked elevation of FGF23 and an increased fractional excretion of phosphate (P) that was associated with a marked reduction of Klotho expression and an increase in FGFR1. After neutralization of FGF23 by anti-FGF23 administration, phosphaturia was still abundant, Klotho expression remained low, and the FGFR1 level was reduced. These results suggest that the expression of renal Klotho is modulated by phosphaturia, whereas the FGFR1 expression is regulated by FGF23. Calcitriol (CTR) administration prevented a decrease in renal Klotho expression. In HEK293 cells HP produced nuclear translocation of β-catenin, together with a reduction in Klotho. Wnt/β-catenin inhibition with Dkk-1 prevented the P-induced down-regulation of Klotho. The addition of CTR to HP medium was able to recover Klotho expression. In summary, high FGF23 levels increase FGFR1, whereas phosphaturia decreases Klotho expression through the activation of Wnt/β-catenin pathway.-Muñoz-Castañeda, J. R., Herencia, C., Pendón-Ruiz de Mier, M. V., Rodriguez-Ortiz, M. E., Diaz-Tocados, J. M., Vergara, N., Martínez-Moreno, J. M., Salmerón, M. D., Richards, W. G., Felsenfeld, A., Kuro-O, M., Almadén, Y., Rodríguez, M. Differential regulation of renal Klotho and FGFR1 in normal and uremic rats. © FASEB.

  4. Inhibition of cAMP-Activated Intestinal Chloride Secretion by Diclofenac: Cellular Mechanism and Potential Application in Cholera

    OpenAIRE

    Pongkorpsakol, Pawin; Pathomthongtaweechai, Nutthapoom; Srimanote, Potjanee; Soodvilai, Sunhapas; Chatsudthipong, Varanuj; Muanprasat, Chatchai

    2014-01-01

    Cyclic AMP-activated intestinal Cl- secretion plays an important role in pathogenesis of cholera. This study aimed to investigate the effect of diclofenac on cAMP-activated Cl- secretion, its underlying mechanisms, and possible application in the treatment of cholera. Diclofenac inhibited cAMP-activated Cl- secretion in human intestinal epithelial (T84) cells with IC50 of ∼ 20 µM. The effect required no cytochrome P450 enzyme-mediated metabolic activation. Interestingly, exposures of T84 cell...

  5. Developmental immunolocalization of the Klotho protein in mouse kidney epithelial cells

    Directory of Open Access Journals (Sweden)

    J.H. Song

    2014-01-01

    Full Text Available A defect in Klotho gene expression in the mouse results in a syndrome that resembles rapid human aging. In this study, we investigated the detailed distribution and the time of the first appearance of Klotho in developing and adult mouse kidney. Kidneys from 16-(F16, 18-(F18 and 20-day-old (F20 fetuses, 1- (P1, 4- (P4, 7- (P7, 14- (P14, and 21-day-old (P21 pups and adults were processed for immunohistochemistry and immunoblot analyses. In the developing mouse kidney, Klotho immunoreactivity was initially observed in a few cells of the connecting tubules (CNT of 18-day-old fetus (F and in the medullary collecting duct (MCD and distal nephron of the F16 developing kidney. In F20, Klotho immunoreactivity was increased in CNT and additionally observed in the outer portion of MCD and tip of the renal papilla. During the first 3 weeks after birth, Klotho-positive cells gradually disappeared from the MCD due to apoptosis, but remained in the CNT and cortical collecting ducts (CCD. In the adult mouse, the Klotho protein was expressed only in a few cells of the CNT and CCD in cortical area. Also, Klotho immunoreactivity was observed in the aquaporin 2-positive CNT, CCD, and NaCl co-transporter-positive distal convoluted tubule (DCT cells and type B and nonA-nonB intercalated cells of CNT, DCT, and CCD. Collectively, our data indicate that immunolocalization of Klotho is closely correlated with proliferation in the intercalated cells of CNT and CCD from aging, and may be involved in the regulation of tubular proliferation.

  6. Mechanisms of Secrets and Secrecy in «El secretario confuso» by Jacinto Cordeiro

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    Mariela Insúa Cereceda

    2015-11-01

    Full Text Available This article studies the mechanism of secrets and secrecy in El secretario confuso (1634, comedy by Jacinto Cordeiro; he is a playwright that belongs to the group of lusitan authors that write in Spanish during the Dual Monarchy period (1580-1640. This work, that can be included in the secretario subtype of comedia palatina genre —based on the infatuation between a noble lady and her secretary— shows thematic and structural coincidences with the main comedies of this moda­lity —El perro del hortelano by Lope de Vega and El vergonzoso en palacio by Tirso de Molina—, but providing new variations to this corpus focussed on the communicational dynamics of remaining silent, concealing and declaring love between the different characters.

  7. Novel compounds targeting the enterohemorrhagic Escherichia coli type three secretion system reveal insights into mechanisms of secretion inhibition.

    Science.gov (United States)

    Zambelloni, Riccardo; Connolly, James P R; Huerta Uribe, Alejandro; Burgess, Karl; Marquez, Rodolfo; Roe, Andrew J

    2017-08-01

    Anti-virulence (AV) compounds are a promising alternative to traditional antibiotics for fighting bacterial infections. The Type Three Secretion System (T3SS) is a well-studied and attractive AV target, given that it is widespread in more than 25 species of Gram-negative bacteria, including enterohemorrhagic E. coli (EHEC), and as it is essential for host colonization by many pathogens. In this work, we designed, synthesized and tested a new series of compounds that block the functionality of the T3SS of EHEC. Affinity chromatography experiments identified the primary target of the compounds as the T3SS needle pore protein EspD, which is essential for effector protein translocation into host cells. These data were supported by mechanistic studies that determined the coiled-coil domain 1 of EspD as a key compound-binding site, thereby preventing correct assembly of the T3SS complex on the cell surface. However, binding of inhibitors to EspD or deletion of EspD itself did not result in transcriptional down-regulation of effector proteins. Instead, we found the compounds to exhibit dual-functionality by also down-regulating transcription of the entire chromosomal locus encoding the T3SS, further demonstrating their desirability and effectiveness. © 2017 The Authors. Molecular Microbiology Published by John Wiley & Sons Ltd.

  8. Cellular mechanisms underlying the inhibitory effect of flufenamic acid on chloride secretion in human intestinal epithelial cells

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    Pawin Pongkorpsakol

    2017-06-01

    Full Text Available Intestinal Cl− secretion is involved in the pathogenesis of secretory diarrheas including cholera. We recently demonstrated that flufenamic acid (FFA suppressed Vibrio cholerae El Tor variant-induced intestinal fluid secretion via mechanisms involving AMPK activation and NF-κB-suppression. The present study aimed to investigate the effect of FFA on transepithelial Cl− secretion in human intestinal epithelial (T84 cells. FFA inhibited cAMP-dependent Cl− secretion in T84 cell monolayers with IC50 of ∼8 μM. Other fenamate drugs including tolfenamic acid, meclofenamic acid and mefenamic acid exhibited the same effect albeit with lower potency. FFA also inhibited activities of CFTR, a cAMP-activated apical Cl− channel, and KCNQ1/KCNE3, a cAMP-activated basolateral K+ channel. Mechanisms of CFTR inhibition by FFA did not involve activation of its negative regulators. Interestingly, FFA inhibited Ca2+-dependent Cl− secretion with IC50 of ∼10 μM. FFA inhibited activities of Ca2+-activated Cl− channels and KCa3.1, a Ca2+-activated basolateral K+ channels, but had no effect on activities of Na+–K+–Cl− cotransporters and Na+–K+ ATPases. These results indicate that FFA inhibits both cAMP and Ca2+-dependent Cl− secretion by suppressing activities of both apical Cl− channels and basolateral K+ channels. FFA and other fenamate drugs may be useful in the treatment of secretory diarrheas.

  9. NH4Cl Treatment Prevents Tissue Calcification in Klotho Deficiency

    Science.gov (United States)

    Leibrock, Christina B.; Alesutan, Ioana; Voelkl, Jakob; Pakladok, Tatsiana; Michael, Diana; Schleicher, Erwin; Kamyabi-Moghaddam, Zahra; Quintanilla-Martinez, Leticia; Kuro-o, Makoto

    2015-01-01

    Klotho, a cofactor in suppressing 1,25(OH)2D3 formation, is a powerful regulator of mineral metabolism. Klotho-hypomorphic mice (kl/kl) exhibit excessive plasma 1,25(OH)2D3, Ca2+, and phosphate concentrations, severe tissue calcification, volume depletion with hyperaldosteronism, and early death. Calcification is paralleled by overexpression of osteoinductive transcription factor Runx2/Cbfa1, Alpl, and senescence-associated molecules Tgfb1, Pai-1, p21, and Glb1. Here, we show that NH4Cl treatment in drinking water (0.28 M) prevented soft tissue and vascular calcification and increased the life span of kl/kl mice >12-fold in males and >4-fold in females without significantly affecting extracellular pH or plasma concentrations of 1,25(OH)2D3, Ca2+, and phosphate. NH4Cl treatment significantly decreased plasma aldosterone and antidiuretic hormone concentrations and reversed the increase of Runx2/Cbfa1, Alpl, Tgfb1, Pai-1, p21, and Glb1 expression in aorta of kl/kl mice. Similarly, in primary human aortic smooth muscle cells (HAoSMCs), NH4Cl treatment reduced phosphate-induced mRNA expression of RUNX2/CBFA1, ALPL, and senescence-associated molecules. In both kl/kl mice and phosphate-treated HAoSMCs, levels of osmosensitive transcription factor NFAT5 and NFAT5-downstream mediator SOX9 were higher than in controls and decreased after NH4Cl treatment. Overexpression of NFAT5 in HAoSMCs mimicked the effect of phosphate and abrogated the effect of NH4Cl on SOX9, RUNX2/CBFA1, and ALPL mRNA expression. TGFB1 treatment of HAoSMCs upregulated NFAT5 expression and prevented the decrease of phosphate-induced NFAT5 expression after NH4Cl treatment. In conclusion, NH4Cl treatment prevents tissue calcification, reduces vascular senescence, and extends survival of klotho-hypomorphic mice. The effects of NH4Cl on vascular osteoinduction involve decrease of TGFB1 and inhibition of NFAT5-dependent osteochondrogenic signaling. PMID:25644113

  10. Soluble klotho may be a marker of phosphate reabsorption.

    Science.gov (United States)

    Tan, Sven-Jean; Smith, Edward R; Holt, Stephen G; Hewitson, Tim D; Toussaint, Nigel D

    2017-06-01

    Background: Membrane-bound α-klotho functions as a co-receptor with fibroblast growth factor receptor at the renal tubule conferring specificity to fibroblast growth factor-23 (FGF-23), allowing it to inhibit tubular phosphate reabsorption at physiological concentrations. α-klotho also exists as a soluble protein. However, the complex interrelationships between soluble α-klotho (sKl), FGF-23 and phosphate reabsorption are poorly understood, with little known about the links between sKl, FGF-23 and phosphate reabsorption in chronic kidney disease (CKD). This study addresses this issue in a cohort of patients with and without CKD. Methods: We conducted a single-centre, cross-sectional study of contemporaneously obtained samples of blood and 24-h urine biochemistry along with sKl and intact FGF-23 (iFGF-23) from non-dialysis-dependent CKD patients and healthy volunteers. Pearson's correlation coefficients were used to determine correlations between natural log-transformed (Ln) sKl and iFGF-23 with other parameters of interest. Backward multivariate analysis was undertaken to evaluate the relationship between mineral parameters. Results: One hundred and sixteen participants (77 with CKD and 39 healthy volunteers) were studied, of which 74 (63.8%) were male. The median age was 61 (interquartile range 49-71) years. Those with CKD had lower sKl (408 versus 542 pg/mL), higher iFGF-23 (94 versus 41 pg/mL), higher fractional excretion of phosphate (25.05 versus 10.98%) and lower daily urinary phosphate excretion (UPE) (24.8 versus 32.3 mmol/L) compared with healthy volunteers (all P  ≤ 0.002). Age correlated inversely and estimated glomerular filtration rate (eGFR) correlated positively with phosphate reabsorption and Ln(sKl), while the opposite was seen with Ln(iFGF23). Upon multivariate analysis, eGFR, Ln(sKl) and parathyroid hormone were independently associated with phosphate reabsorption, whereas Ln(iFGF-23) was not, after adjustment for age. Conclusions

  11. Activation of the Anti-Aging and Cognition-Enhancing Gene Klotho by CRISPR-dCas9 Transcriptional Effector Complex.

    Science.gov (United States)

    Chen, Ci-Di; Zeldich, Ella; Li, Yuexuan; Yuste, Andrea; Abraham, Carmela R

    2018-02-01

    Multiple lines of evidence show that the anti-aging and cognition-enhancing protein Klotho fosters neuronal survival, increases the anti-oxidative stress defense, and promotes remyelination of demyelinated axons. Thus, upregulation of the Klotho gene can potentially alleviate the symptoms and/or prevent the progression of age-associated neurodegenerative diseases such as Alzheimer's disease and demyelinating diseases such as multiple sclerosis. Here we used a CRISPR-dCas9 complex to investigate single-guide RNA (sgRNA) targeting the Klotho promoter region for efficient transcriptional activation of the Klotho gene. We tested the sgRNAs within the - 1 to - 300 bp of the Klotho promoter region and identified two sgRNAs that can effectively enhance Klotho gene transcription. We examined the transcriptional activation of the Klotho gene using three different systems: a Firefly luciferase (FLuc) and NanoLuc luciferase (NLuc) coincidence reporter system, a NLuc knock-in in Klotho 3'-UTR using CRISPR genomic editing, and two human cell lines: neuronal SY5Y cells and kidney HK-2 cells that express Klotho endogenously. The two sgRNAs enhanced Klotho expression at both the gene and protein levels. Our results show the feasibility of gene therapy for targeting Klotho using CRISPR technology. Enhancing Klotho levels has a therapeutic potential for increasing cognition and treating age-associated neurodegenerative, demyelinating and other diseases, such as chronic kidney disease and cancer.

  12. Molecular Mechanisms in Amyotrophic Lateral Sclerosis: The Role of Angiogenin, a Secreted RNase

    Directory of Open Access Journals (Sweden)

    Isabela M. Aparicio-Erriu

    2012-11-01

    Full Text Available Amyotrophic lateral sclerosis is a fatal neurodegenerative disease caused by the loss of motoneurons. The precise molecular and cellular basis for neuronal death is not yet well established, but the contemporary view is that it is a culmination of multiple aberrant biological processes. Among the proposed mechanisms of motoneuron degeneration, alterations in the homeostasis of RNA binding proteins (RBP and the consequent changes in RNA metabolism have received attention recently.The ribonuclease, angiogenin was one of the first RBPs associated with familial and sporadic ALS. It is enriched in motoneurons under physiological conditions, and is required for motoneuron survival under stress conditions. Furthermore, delivery of angiogenin protects cultured motoneurons against stress-induced injury, and significantly increases the survival of motoneurons in SODG93A mice. In this overview on the role of angiogenin in RNA metabolism and in the control of motoneuron survival, we discuss potential pathogenic mechanisms of angiogenin dysfunction relevant to ALS and other neurodegenerative disorders. We also discuss recent evidence demonstrating that angiogenin secreted from stressed motoneurons may alter RNA metabolism in astrocytes.

  13. Klotho expression in long bones regulates FGF23 production during renal failure.

    Science.gov (United States)

    Kaludjerovic, Jovana; Komaba, Hirotaka; Sato, Tadatoshi; Erben, Reinhold G; Baron, Roland; Olauson, Hannes; Larsson, Tobias E; Lanske, Beate

    2017-05-01

    Circulating levels of bone-derived fibroblast growth factor 23 (FGF23) increase early during acute and chronic kidney disease and are associated with adverse outcomes. Membrane-bound Klotho acts as a permissive coreceptor for FGF23, and its expression was recently found in osteoblasts/osteocytes. We hypothesized that Klotho in bone cells is part of an autocrine feedback loop that regulates FGF23 expression during renal failure. Thus, we induced renal failure in mice with targeted deletion of Klotho in long bones. Uremic wild-type ( KL fl/fl ) and knockout ( Prx1-Cre;KL fl/fl ) mice both responded with reduced body weight, kidney atrophy, hyperphosphatemia, and increased bone turnover. Importantly, long bones of Prx1-Cre;KL fl/fl mice but not their axial skeleton failed to increase FGF23 expression as observed in uremic KL fl/fl mice. Consequently, Prx1-Cre;KL fl/fl mice had significantly lower serum FGF23 and parathyroid hormone levels, and higher renal 1-α-hydroxylase expression, serum 1,25-dihydroxyvitamin D, and calcium levels than KL fl/fl mice. These results were confirmed in two independent models of renal failure, adenine diet induced and 5/6 nephrectomy. Moreover, FGF23-treated bone cells required Klotho to increase FGF23 mRNA and ERK phosphorylation. In summary, our novel findings show that Klotho in bone is crucial for inducing FGF23 production upon renal failure. We propose the presence of an autocrine feedback loop in which Klotho senses the need for FGF23.-Kaludjerovic, J., Komaba, H., Sato, T., Erben, R. G., Baron, R., Olauson, H., Larsson, T. E., Lanske, B. Klotho expression in long bones regulates FGF23 production during renal failure. © FASEB.

  14. Characterization of vitamin D-deficient klotho(-/-) mice: do increased levels of serum 1,25(OH)2D3 cause disturbed calcium and phosphate homeostasis in klotho(-/-) mice?

    NARCIS (Netherlands)

    Woudenberg-Vrenken, T.E.; van der Eerden, B.C.; van der Kemp, A.W.; Leeuwen, J.P. van; Bindels, R.J.M.; Hoenderop, J.G.J.

    2012-01-01

    BACKGROUND: Klotho(-/-) mice display disturbed Ca(2+) and vitamin D homeostasis. Renal cytochrome p450 27b1 (Cyp27b1), the enzyme that catalyzes the hydrolysis to 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)), is increased in klotho(-/-) mice, and a 1,25(OH)(2)D(3)-deficient diet partially normalized

  15. Changes in expression of klotho affect physiological processes, diseases, and cancer

    Directory of Open Access Journals (Sweden)

    Nguyen Xuan

    2018-01-01

    Full Text Available Klotho (KL encodes a single-pass transmembrane protein and is predominantly expressed in the kidney, parathyroid glands, and choroid plexus. Genetic studies on the KL gene have revealed that DNA hypermethylation is one of the major risk factors for aging, diseases, and cancer. Besides, KL exerts anti-inflammatory and anti-tumor effects by regulating signaling pathways and the expression of target genes. KL participates in modulation of the insulin/insulin-like growth factor-1 (IGF-1 signaling, which induces the growth hormone (GH secretion. Accordingly, KL mutant mice display multiple aging-like phenotypes, which are ameliorated by overexpression of KL. Therefore, KL is an important contributor to lifespan. KL is further identified as a regulator of calcium (Ca2+ channel-dependent cell physiological processes. KL has been also shown to induce cancer cell apoptosis, thus, it is considered as a potential tumor suppressor. Our recent studies have indicated that KL modulates an influx of Ca2+ from the extracellular space, leading to a change in CCL21-dependent migration in dendritic cells (DCs. Interestingly, the regulation of the expression of KL was mediated through a phosphoinositide 3-kinase (PI3K pathway in DCs. Moreover, downregulating of KL expression by using siRNA knockdown technique, we observed that the expression of Ca2+ channels including Orai3, but not Orai1, Orai2, TRPV5 and TRPV6 was significantly reduced in KL-silenced as compared to control BMDCs. Clearly, additional research is required to define the role of KL in the regulation of organismic and cellular functions through the PI3K signaling and the expression of the Ca2+ channels.

  16. Association of Klotho and interleukin 6 gene polymorphisms with aging in Han Chinese population.

    Science.gov (United States)

    Zhang, W-G; Bai, X-J; Chen, D-P; Lv, Y; Sun, X-F; Cai, G-Y; Bai, X-Y; Chen, X-M

    2014-12-01

    Certain gene polymorphisms are associated with human aging. This study investigated polymorphisms of a metabolism-related gene, Klotho, and an inflammatory gene, IL6, for association with the aging process in a healthy Han Chinese population. A total of 482 healthy subjects were recruited and divided into aging and young groups according to chronological age and biological age. Snapshots were used to detect a Klotho gene tag SNP (rs571118) and the F-SNPs rs9536314 (F352V) and rs9527025 (C370S), and an interleukin 6 (IL-6) gene tag SNP (rs1524107) and the F-SNPs rs1800795 (-174G/C) and rs1800796 (-572G/C). Klotho F352V and IL-6-174G/C was G homozygous, C370S was T homozygous while IL-6-572G/C MAF less than 5%. There was a statistically significant difference in the Klotho rs571118 SNP between chronological age groups, but not biological age groups. However, other SNPs, including IL-6 gene SNPs, didn't correlate with age in the Han Chinese population. Human aging is a complex process that includes chronological and biological aging. Our current data showed that Klotho gene rs571118 SNP was associated with chronological aging, but not biological aging, in a Han Chinese population. Further study will investigate genetic build up for the difference between chronological and biological aging.

  17. Initial study on the possible mechanisms involved in the effects of high doses of perfluorooctane sulfonate (PFOS) on prolactin secretion.

    Science.gov (United States)

    Salgado, R; Pereiro, N; López-Doval, S; Lafuente, A

    2015-09-01

    Perfluorooctane sulfonate (PFOS) is a fluorinated organic compound. This chemical is neurotoxic and can alter the pituitary secretion. This is an initial study aimed at knowing the toxic effects of high doses of PFOS on prolactin secretion and the possible mechanisms involved in these alterations. For that, adult male rats were orally treated with 3.0 and 6.0 mg of PFOS/kg body weight (b.w.)/day for 28 days. At the end of the treatment, the serum levels of prolactin and estradiol as well as the concentration of dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and gamma-aminobutyric acid (GABA) were quantified in the anterior and in the mediobasal hypothalamus. PFOS, at the administered doses, reduced prolactin and estradiol secretion, increased the concentration of dopamine and GABA in the anterior hypothalamus, and decreased the ratios DOPAC/dopamine and HVA/dopamine in this same hypothalamic area. The outcomes reported in this study suggest that (1) high doses of PFOS inhibit prolactin secretion in adult male rats; (2) only the periventricular-hypophysial dopaminergic (PHDA) neurons seem to be involved in this inhibitory effect but not the tuberoinfundibular dopaminergic (TIDA) and the tuberohypophysial dopaminergic (THDA) systems; (3) GABAergic cells from the paraventricular and supraoptic nuclei could be partially responsible for the PFOS action on prolactin secretion; and finally (4) estradiol might take part in the inhibition exerted by elevated concentration of PFOS on prolactin release. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Leaf blade structure of Verbesina macrophylla (Cass.) F. S. Blake (Asteraceae): ontogeny, duct secretion mechanism and essential oil composition.

    Science.gov (United States)

    Bezerra, L D A; Mangabeira, P A O; de Oliveira, R A; Costa, L C D B; Da Cunha, M

    2018-05-01

    Secretory structures are common in Asteraceae, where they exhibit a high degree of morphological diversity. The species Verbesina macrophylla, popularly known as assa-peixe, is native to Brazil where it is widely used for medicinal purposes. Despite its potential medical importance, there have been no studies of the anatomy of this species, especially its secretory structures and secreted compounds. This study examined leaves of V. macrophylla with emphasis on secretory structures and secreted secondary metabolites. Development of secretory ducts and the mechanism of secretion production are described for V. macrophylla using ultrastructure, yield and chemical composition of its essential oils. Verbesina macrophylla has a hypostomatic leaf blade with dorsiventral mesophyll and secretory ducts associated with vascular bundles of schizogenous origin. Histochemistry identified the presence of lipids, terpenes, alkaloids and mucopolysaccharides. Ultrastructure suggests that the secretion released into the duct lumen is produced in plastids of transfer cells, parenchymal sheath cells and stored in vacuoles in these cells and duct epithelial cells. The essential oil content was 0.8%, and its major components were germacrene D, germacrene D-4-ol, β-caryophyllene, bicyclogermacrene and α-cadinol. Secretory ducts of V. macrophylla are squizogenous. Substances identified in tissues suggest that both secretions stored in the ducts and in adjacent parenchyma cells are involved in chemical defence. The essential oil is rich in sesquiterpenes, with germacrene D and its derivatives being notable components. © 2018 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

  19. The possible mechanisms by which maternal hypothyroidism impairs insulin secretion in adult male offspring in rats.

    Science.gov (United States)

    Karbalaei, Narges; Ghasemi, Asghar; Hedayati, Mehdi; Godini, Aliashraf; Zahediasl, Saleh

    2014-04-01

    Previous studies have recently shown that maternal hypothyroidism leads to impaired glucose metabolism and reduced insulin secretion in adult offspring in rats. The aim of this study was to locate the defect in the insulin secretion pathway induced by maternal hypothyroidism. Pregnant Wistar rats were divided into two groups; the control group consumed water, while the hypothyroid (FH) group received water containing 0.025% 6-propyl-2-thiouracil during gestation. An intravenous glucose tolerance test was carried out on 5-month-old male offspring. In in vitro studies, the effects of various secretagogues and inhibitors acting at different levels of the insulin secretion cascade were investigated, and insulin content, insulin secretion and glucokinase activity of the islets were compared. Although insulin content of the FH islets did not differ from that of control islets, insulin secretion from FH islets was reduced when it was challenged by glucose or arginine. Compared with control islets, activities of both hexokinase and glucokinase were also significantly decreased in the FH islets. Although, in both groups, increasing glibenclamide and nifedipine concentrations in the presence of 16.7 mmol l(-1) glucose increased and decreased insulin secretion, respectively, the percentage of changes in secretion of FH islets was significantly lower compared with control islets. The response of FH islets to high extracellular potassium concentration and diazoxide was also significantly lower than that of the control islets. These findings demonstrate that impaired insulin secretion in the FH group is probably related to alterations in different steps of the insulin secretion pathway and not in the insulin pool of β-cells.

  20. Inhibition of cAMP-activated intestinal chloride secretion by diclofenac: cellular mechanism and potential application in cholera.

    Science.gov (United States)

    Pongkorpsakol, Pawin; Pathomthongtaweechai, Nutthapoom; Srimanote, Potjanee; Soodvilai, Sunhapas; Chatsudthipong, Varanuj; Muanprasat, Chatchai

    2014-09-01

    Cyclic AMP-activated intestinal Cl- secretion plays an important role in pathogenesis of cholera. This study aimed to investigate the effect of diclofenac on cAMP-activated Cl- secretion, its underlying mechanisms, and possible application in the treatment of cholera. Diclofenac inhibited cAMP-activated Cl- secretion in human intestinal epithelial (T84) cells with IC50 of ∼ 20 µM. The effect required no cytochrome P450 enzyme-mediated metabolic activation. Interestingly, exposures of T84 cell monolayers to diclofenac, either in apical or basolateral solutions, produced similar degree of inhibitions. Analyses of the apical Cl- current showed that diclofenac reversibly inhibited CFTR Cl- channel activity (IC50 ∼ 10 µM) via mechanisms not involving either changes in intracellular cAMP levels or CFTR channel inactivation by AMP-activated protein kinase and protein phosphatase. Of interest, diclofenac had no effect on Na(+)-K(+) ATPases and Na(+)-K(+)-Cl- cotransporters, but inhibited cAMP-activated basolateral K(+) channels with IC50 of ∼ 3 µM. In addition, diclofenac suppressed Ca(2+)-activated Cl- channels, inwardly rectifying Cl- channels, and Ca(2+)-activated basolateral K(+) channels. Furthermore, diclofenac (up to 200 µM; 24 h of treatment) had no effect on cell viability and barrier function in T84 cells. Importantly, cholera toxin (CT)-induced Cl- secretion across T84 cell monolayers was effectively suppressed by diclofenac. Intraperitoneal administration of diclofenac (30 mg/kg) reduced both CT and Vibrio cholerae-induced intestinal fluid secretion by ∼ 70% without affecting intestinal fluid absorption in mice. Collectively, our results indicate that diclofenac inhibits both cAMP-activated and Ca(2+)-activated Cl- secretion by inhibiting both apical Cl- channels and basolateral K+ channels in intestinal epithelial cells. Diclofenac may be useful in the treatment of cholera and other types of secretory diarrheas resulting from intestinal

  1. Inhibition of cAMP-activated intestinal chloride secretion by diclofenac: cellular mechanism and potential application in cholera.

    Directory of Open Access Journals (Sweden)

    Pawin Pongkorpsakol

    2014-09-01

    Full Text Available Cyclic AMP-activated intestinal Cl- secretion plays an important role in pathogenesis of cholera. This study aimed to investigate the effect of diclofenac on cAMP-activated Cl- secretion, its underlying mechanisms, and possible application in the treatment of cholera. Diclofenac inhibited cAMP-activated Cl- secretion in human intestinal epithelial (T84 cells with IC50 of ∼ 20 µM. The effect required no cytochrome P450 enzyme-mediated metabolic activation. Interestingly, exposures of T84 cell monolayers to diclofenac, either in apical or basolateral solutions, produced similar degree of inhibitions. Analyses of the apical Cl- current showed that diclofenac reversibly inhibited CFTR Cl- channel activity (IC50 ∼ 10 µM via mechanisms not involving either changes in intracellular cAMP levels or CFTR channel inactivation by AMP-activated protein kinase and protein phosphatase. Of interest, diclofenac had no effect on Na(+-K(+ ATPases and Na(+-K(+-Cl- cotransporters, but inhibited cAMP-activated basolateral K(+ channels with IC50 of ∼ 3 µM. In addition, diclofenac suppressed Ca(2+-activated Cl- channels, inwardly rectifying Cl- channels, and Ca(2+-activated basolateral K(+ channels. Furthermore, diclofenac (up to 200 µM; 24 h of treatment had no effect on cell viability and barrier function in T84 cells. Importantly, cholera toxin (CT-induced Cl- secretion across T84 cell monolayers was effectively suppressed by diclofenac. Intraperitoneal administration of diclofenac (30 mg/kg reduced both CT and Vibrio cholerae-induced intestinal fluid secretion by ∼ 70% without affecting intestinal fluid absorption in mice. Collectively, our results indicate that diclofenac inhibits both cAMP-activated and Ca(2+-activated Cl- secretion by inhibiting both apical Cl- channels and basolateral K+ channels in intestinal epithelial cells. Diclofenac may be useful in the treatment of cholera and other types of secretory diarrheas resulting from intestinal

  2. Recombinant α-Klotho may be prophylactic and therapeutic for acute to chronic kidney disease progression and uremic cardiomyopathy.

    Science.gov (United States)

    Hu, Ming Chang; Shi, Mingjun; Gillings, Nancy; Flores, Brianna; Takahashi, Masaya; Kuro-O, Makoto; Moe, Orson W

    2017-05-01

    α-Klotho is highly expressed in the kidney, and its extracellular domain is cleaved and released into the circulation. Chronic kidney disease (CKD) is a state of α-Klotho deficiency, which exerts multiple negative systemic effects on numerous organs including the cardiovascular system. Since acute kidney injury (AKI) greatly escalates the risk of CKD development, we explored the effect of α-Klotho on prevention and treatment on post-AKI to CKD progression and cardiovascular disease. Therein, ischemia reperfusion injury-induced AKI was followed by early administration of recombinant α-Klotho or vehicle starting one day and continued for four days after kidney injury (CKD prevention protocol). A CKD model was generated by unilateral nephrectomy plus contralateral ischemia reperfusion injury. Late administration of α-Klotho in this model was started four weeks after injury and sustained for 12 weeks (CKD treatment protocol). The prevention protocol precluded AKI to CKD progression and protected the heart from cardiac remodeling in the post-AKI model. One important effect of exogenous α-Klotho therapy was the restoration of endogenous α-Klotho levels long after the cessation of exogenous α-Klotho therapy. The treatment protocol still effectively improved renal function and attenuated cardiac remodeling in CKD, although these parameters did not completely return to normal. In addition, α-Klotho administration also attenuated high phosphate diet-induced renal and cardiac fibrosis, and improved renal and cardiac function in the absence of pre-existing renal disease. Thus, recombinant α-Klotho protein is safe and efficacious, and might be a promising prophylactic or therapeutic option for prevention or retardation of AKI-to-CKD progression and uremic cardiomyopathy. Copyright © 2017 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

  3. Serum klotho: relation to fibroblast growth factor-23 and other regulators of phosphate metabolism in children with chronic kidney disease.

    Science.gov (United States)

    Sawires, Happy K; Essam, Rasha M; Morgan, Marian F; Mahmoud, Rasha A

    2015-01-01

    FGF23 and Klotho synergize to regulate phosphate homeostasis by promoting renal phosphate excretion. Chronic kidney disease (CKD) may be viewed as a state of FGF23 resistance caused by Klotho deficiency. This viewpoint explains several observations on phosphate metabolism in CKD that lack mechanistic insights. Our objectives were to correlate serum klotho and FGF-23 with other variables that regulate phosphate metabolism. We studied 40 patients with CKD on conservative treatment (group A), 44 patients with end-stage renal disease (ESRD) on regular hemodialysis (group B), 40 kidney transplant recipients (KTR) (group C) and 40 healthy controls for measuring serum klotho and FGF-23. Blood samples were withdrawn for measuring the levels of serum Calcium (Ca), Phosphorus (P), alkaline phosphatase (ALP), 1,25 (OH)2 D3, intact parathyroid hormone (PTH), FGF-23 and α klotho. The mean levels of FGF-23 and α klotho in control group were 225.78 ± 111.05 pg/ml (range: 102.4, 418.5) and 6.78 ± 1.90 ng/ml (range: 4, 11), respectively. The mean levels of FGF-23 in the 3 studied groups were 1,034.2 ± 84.6, 1,288.7 ± 131.4 and 1,008.7 ± 117.6 pg/ml, respectively. The median levels of s-klotho in the 3 studied groups were 3.15, 2.3 and 2.95, respectively. It was found that FGF-23 was significantly increased and α klotho was significantly decreased in all patients when compared with those in the control group (p 0.05). We have shown that circulating s-klotho was not related to FGF-23 in CKD, dialysis and KTR patients. In addition, we demonstrated a novel association between serum Ca and s-klotho that needs to be further studied. © 2015 S. Karger AG, Basel.

  4. Molecular Mechanisms of Glucose-Stimulated GLP-1 Secretion From Perfused Rat Small Intestine

    DEFF Research Database (Denmark)

    Kuhre, Rune E.; Frost, Charlotte R.; Svendsen, Berit

    2015-01-01

    /v) stimulated the secretion dose dependently, but vascular glucose was without significant effect at 5, 10, 15, and 25 mmol/L. GLP-1 stimulation by luminal glucose (20%) secretion was blocked by the voltage-gated Ca channel inhibitor, nifedipine, or by hyperpolarization with diazoxide. Luminal administration...... not stimulate a response. Luminal glucose-stimulated GLP-1 secretion was also sensitive to luminal GLUT2 inhibition (phloretin), but in contrast to SGLT1 inhibition, phloretin did not eliminate the response, and luminal glucose (20%) stimulated larger GLP-1 responses than luminal α-MGP in matched concentrations...

  5. Corticotropin-releasing factor. Mechanisms to inhibit gastric acid secretion in conscious dogs.

    OpenAIRE

    Lenz, H J; Hester, S E; Brown, M R

    1985-01-01

    Immunoreactivity similar to that of corticotropin-releasing factor (CRF) is found in regions of the central nervous system that modulate autonomic responses, including gastrointestinal functions. We examined the central nervous system effects of ovine CRF on gastric acid secretion in conscious dogs. Male beagle dogs (11-13 kg) were fitted with chronic intracerebroventricular cannulae and gastric fistulae. Gastric acid secretion in response to intravenously administered gastric secretory stimu...

  6. Mechanisms of fat-induced gastric inhibitory polypeptide/glucose-dependent insulinotropic polypeptide secretion from K cells.

    Science.gov (United States)

    Yamane, Shunsuke; Harada, Norio; Inagaki, Nobuya

    2016-04-01

    Gastric inhibitory polypeptide/glucose-dependent insulinotropic polypeptide (GIP) is one of the incretins, which are gastrointestinal hormones released in response to nutrient ingestion and potentiate glucose-stimulated insulin secretion. Single fat ingestion stimulates GIP secretion from enteroendocrine K cells; chronic high-fat diet (HFD) loading enhances GIP secretion and induces obesity in mice in a GIP-dependent manner. However, the mechanisms of GIP secretion from K cells in response to fat ingestion and GIP hypersecretion in HFD-induced obesity are not well understood. We generated GIP-green fluorescent protein knock-in (GIP (gfp/+)) mice, in which K cells are labeled by enhanced GIP-green fluorescent protein. Microarray analysis of isolated K cells from GIP (gfp/+) mice showed that both fatty acid-binding protein 5 and G protein-coupled receptor 120 are highly expressed in K cells. Single oral administration of fat resulted in significant reduction of GIP secretion in both fatty acid-binding protein 5- and G protein-coupled receptor 120-deficient mice, showing that fatty acid-binding protein 5 and G protein-coupled receptor 120 are involved in acute fat-induced GIP secretion. Furthermore, the transcriptional factor, regulatory factor X6 (Rfx6), is highly expressed in K cells. In vitro experiments using the mouse enteroendocrine cell line, STC-1, showed that GIP messenger ribonucleic acid levels are upregulated by Rfx6. Expression levels of Rfx6 messenger ribonucleic acid as well as that of GIP messenger ribonucleic acid were augmented in the K cells of HFD-induced obese mice, in which GIP content in the small intestine is increased compared with that in lean mice fed a control diet. These results suggest that Rfx6 is involved in hypersecretion of GIP in HFD-induced obese conditions by increasing GIP gene expression.

  7. Analysis of the outer membrane proteome and secretome of Bacteroides fragilis reveals a multiplicity of secretion mechanisms.

    Directory of Open Access Journals (Sweden)

    Marlena M Wilson

    Full Text Available Bacteroides fragilis is a widely distributed member of the human gut microbiome and an opportunistic pathogen. Cell surface molecules produced by this organism likely play important roles in colonization, communication with other microbes, and pathogenicity, but the protein composition of the outer membrane (OM and the mechanisms used to transport polypeptides into the extracellular space are poorly characterized. Here we used LC-MS/MS to analyze the OM proteome and secretome of B. fragilis NCTC 9343 grown under laboratory conditions. Of the 229 OM proteins that we identified, 108 are predicted to be lipoproteins, and 61 are predicted to be TonB-dependent transporters. Based on their proximity to genes encoding TonB-dependent transporters, many of the lipoprotein genes likely encode proteins involved in nutrient or small molecule uptake. Interestingly, protease accessibility and biotinylation experiments indicated that an unusually large fraction of the lipoproteins are cell-surface exposed. We also identified three proteins that are members of a novel family of autotransporters, multiple potential type I protein secretion systems, and proteins that appear to be components of a type VI secretion apparatus. The secretome consisted of lipoproteins and other proteins that might be substrates of the putative type I or type VI secretion systems. Our proteomic studies show that B. fragilis differs considerably from well-studied Gram-negative bacteria such as Escherichia coli in both the spectrum of OM proteins that it produces and the range of secretion strategies that it utilizes.

  8. Subcellular localization and mechanism of secretion of vascular endothelial growth factor in human skeletal muscle

    DEFF Research Database (Denmark)

    Høier, Birgitte; Prats Gavalda, Clara; Qvortrup, Klaus

    2013-01-01

    The subcellular distribution and secretion of vascular endothelial growth factor (VEGF) was examined in skeletal muscle of healthy humans. Skeletal muscle biopsies were obtained from m.v. lateralis before and after a 2 h bout of cycling exercise. VEGF localization was conducted on preparations...

  9. Reduction of Oxidative Stress in Chronic Kidney Disease Does Not Increase Circulating α-Klotho Concentrations.

    Directory of Open Access Journals (Sweden)

    Aaltje Y Adema

    Full Text Available The CKD-associated decline in soluble α-Klotho levels is considered detrimental. Some in vitro and in vivo animal studies have shown that anti-oxidant therapy can upregulate the expression of α-Klotho in the kidney. We examined the effect of anti-oxidant therapy on α-Klotho concentrations in a clinical cohort with mild tot moderate chronic kidney disease (CKD. We performed a post-hoc analysis of a prospective randomized trial involving 62 patients with mild to moderate CKD (the ATIC study, all using an angiotensin-converting enzyme inhibitor (ACEi or angiotensin receptor blocker (ARB for 12 months. On top of that, the intervention group received anti-oxidative therapy consisting of the combination of pravastatin (40 mg/d and vitamin E (α-tocopherol acetate, 300 mg/d while the placebo was not treated with anti-oxidants. α-Klotho concentrations were measured at baseline and after 12 months of anti-oxidant therapy. Data were analysed using T-tests and Generalized Estimating Equations, adjusting for potential confounders such as vitamin D, parathyroid hormone, fibroblast-growth-factor 23 (FGF23 and eGFR. The cohort existed of 62 patients with an eGFR (MDRD of 35 ± 14 ml/min/1.72 m2, 34 were male and mean age was 53.0 ± 12.5 years old. Anti-oxidative therapy did successfully reduce oxLDL and LDL concentrations (P <0.001. α-Klotho concentrations did not change in patients receiving either anti-oxidative therapy (476.9 ± 124.3 to 492.7 ± 126.3 pg/mL, P = 0.23 nor in those receiving placebo 483.2 ± 142.5 to 489.6 ± 120.3 pg/mL, P = 0.62. Changes in α-Klotho concentrations were not different between both groups (p = 0.62. No evidence was found that anti-oxidative therapy affected α-Klotho concentrations in patients with mild-moderate CKD.

  10. Mathematical Modeling of Interacting Glucose-Sensing Mechanisms and Electrical Activity Underlying Glucagon-Like Peptide 1 Secretion.

    Directory of Open Access Journals (Sweden)

    Michela Riz

    2015-12-01

    Full Text Available Intestinal L-cells sense glucose and other nutrients, and in response release glucagon-like peptide 1 (GLP-1, peptide YY and other hormones with anti-diabetic and weight-reducing effects. The stimulus-secretion pathway in L-cells is still poorly understood, although it is known that GLP-1 secreting cells use sodium-glucose co-transporters (SGLT and ATP-sensitive K+-channels (K(ATP-channels to sense intestinal glucose levels. Electrical activity then transduces glucose sensing to Ca2+-stimulated exocytosis. This particular glucose-sensing arrangement with glucose triggering both a depolarizing SGLT current as well as leading to closure of the hyperpolarizing K(ATP current is of more general interest for our understanding of glucose-sensing cells. To dissect the interactions of these two glucose-sensing mechanisms, we build a mathematical model of electrical activity underlying GLP-1 secretion. Two sets of model parameters are presented: one set represents primary mouse colonic L-cells; the other set is based on data from the GLP-1 secreting GLUTag cell line. The model is then used to obtain insight into the differences in glucose-sensing between primary L-cells and GLUTag cells. Our results illuminate how the two glucose-sensing mechanisms interact, and suggest that the depolarizing effect of SGLT currents is modulated by K(ATP-channel activity. Based on our simulations, we propose that primary L-cells encode the glucose signal as changes in action potential amplitude, whereas GLUTag cells rely mainly on frequency modulation. The model should be useful for further basic, pharmacological and theoretical investigations of the cellular signals underlying endogenous GLP-1 and peptide YY release.

  11. Chest compression with a higher level of pressure support ventilation: effects on secretion removal, hemodynamics, and respiratory mechanics in patients on mechanical ventilation

    Directory of Open Access Journals (Sweden)

    Wagner da Silva Naue

    2014-01-01

    Full Text Available OBJECTIVE: To determine the efficacy of chest compression accompanied by a 10-cmH2O increase in baseline inspiratory pressure on pressure support ventilation, in comparison with that of aspiration alone, in removing secretions, normalizing hemodynamics, and improving respiratory mechanics in patients on mechanical ventilation. METHODS: This was a randomized crossover clinical trial involving patients on mechanical ventilation for more than 48 h in the ICU of the Porto Alegre Hospital de Clínicas, in the city of Porto Alegre, Brazil. Patients were randomized to receive aspiration alone (control group or compression accompanied by a 10-cmH2O increase in baseline inspiratory pressure on pressure support ventilation (intervention group. We measured hemodynamic parameters, respiratory mechanics parameters, and the amount of secretions collected. RESULTS: We included 34 patients. The mean age was 64.2 ± 14.6 years. In comparison with the control group, the intervention group showed a higher median amount of secretions collected (1.9 g vs. 2.3 g; p = 0.004, a greater increase in mean expiratory tidal volume (16 ± 69 mL vs. 56 ± 69 mL; p = 0.018, and a greater increase in mean dynamic compliance (0.1 ± 4.9 cmH2O vs. 2.8 ± 4.5 cmH2O; p = 0.005. CONCLUSIONS: In this sample, chest compression accompanied by an increase in pressure support significantly increased the amount of secretions removed, the expiratory tidal volume, and dynamic compliance. (ClinicalTrials.gov Identifier:NCT01155648 [http://www.clinicaltrials.gov/

  12. Magnesium modulates parathyroid hormone secretion and upregulates parathyroid receptor expression at moderately low calcium concentration.

    Science.gov (United States)

    Rodríguez-Ortiz, Maria E; Canalejo, Antonio; Herencia, Carmen; Martínez-Moreno, Julio M; Peralta-Ramírez, Alan; Perez-Martinez, Pablo; Navarro-González, Juan F; Rodríguez, Mariano; Peter, Mirjam; Gundlach, Kristina; Steppan, Sonja; Passlick-Deetjen, Jutta; Muñoz-Castañeda, Juan R; Almaden, Yolanda

    2014-02-01

    The interest on magnesium (Mg) has grown since clinical studies have shown the efficacy of Mg-containing phosphate binders. However, some concern has arisen for the potential effect of increased serum Mg on parathyroid hormone (PTH) secretion. Our objective was to evaluate the direct effect of Mg in the regulation of the parathyroid function; specifically, PTH secretion and the expression of parathyroid cell receptors: CaR, the vitamin D receptor (VDR) and FGFR1/Klotho. The work was performed in vitro by incubating intact rat parathyroid glands in different calcium (Ca) and Mg concentrations. Increasing Mg concentrations from 0.5 to 2 mM produced a left shift of PTH-Ca curves. With Mg 5 mM, the secretory response was practically abolished. Mg was able to reduce PTH only if parathyroid glands were exposed to moderately low Ca concentrations; with normal-high Ca concentrations, the effect of Mg on PTH inhibition was minor or absent. After 6-h incubation at a Ca concentration of 1.0 mM, the expression of parathyroid CaR, VDR, FGFR1 and Klotho (at mRNA and protein levels) was increased with a Mg concentration of 2.0 when compared with 0.5 mM. Mg reduces PTH secretion mainly when a moderate low calcium concentration is present; Mg also modulates parathyroid glands function through upregulation of the key cellular receptors CaR, VDR and FGF23/Klotho system.

  13. Flavins secreted by roots of iron-deficient Beta vulgaris enable mining of ferric oxide via reductive mechanisms.

    Science.gov (United States)

    Sisó-Terraza, Patricia; Rios, Juan J; Abadía, Javier; Abadía, Anunciación; Álvarez-Fernández, Ana

    2016-01-01

    Iron (Fe) is abundant in soils but generally poorly soluble. Plants, with the exception of Graminaceae, take up Fe using an Fe(III)-chelate reductase coupled to an Fe(II) transporter. Whether or not nongraminaceous species can convert scarcely soluble Fe(III) forms into soluble Fe forms has deserved little attention so far. We have used Beta vulgaris, one among the many species whose roots secrete flavins upon Fe deficiency, to study whether or not flavins are involved in Fe acquisition. Flavins secreted by Fe-deficient plants were removed from the nutrient solution, and plants were compared with Fe-sufficient plants and Fe-deficient plants without flavin removal. Solubilization of a scarcely soluble Fe(III)-oxide was assessed in the presence or absence of flavins, NADH (nicotinamide adenine dinucleotide, reduced form) or plant roots, and an Fe(II) trapping agent. The removal of flavins from the nutrient solution aggravated the Fe deficiency-induced leaf chlorosis. Flavins were able to dissolve an Fe(III)-oxide in the presence of NADH. The addition of extracellular flavins enabled roots of Fe-deficient plants to reductively dissolve an Fe(III)-oxide. We concluded that root-secretion of flavins improves Fe nutrition in B. vulgaris. Flavins allow B. vulgaris roots to mine Fe from Fe(III)-oxides via reductive mechanisms. © 2015 CSIC New Phytologist © 2015 New Phytologist Trust.

  14. Evaluation of the Effect of Nebulized N-Acetylcysteine on Respiratory Secretions in Mechanically Ventilated Patients: Randomized Clinical Trial

    Directory of Open Access Journals (Sweden)

    Seyed Masoom Masoompour

    2015-07-01

    Full Text Available Background: The purpose of our study was to evaluate an inexpensive and available method to reduce mucous impactions in mechanically ventilated patients. Methods: This randomized clinical trial was conducted on 40 mechanically ventilated patients aged 15-90 years. The patients were randomly allocated into two arms; 20 cases and 20 controls. The cases received N-acetylcysteine via their nebulizers, and the control group received normal saline three times a day for one day. We measured the density of respiratory secretion, plateau and peak airway pressures, and O2 saturation at baseline, 12 and 24 hours later. Results: Although the mean secretion density was significantly lower in the NAC group (F (1, 38=8.61, P=0.006, but a repeated measures ANOVA with a Greenhouse-Geisser correction determined that the effect of NAC on mean secretion density did not differ significantly between time points (F (1, 38=3.08, P=0.087. NAC increased O2 saturation significantly between time points (F (1.92, 73.1=4.6, P=0.014. The plateau airway pressures were relatively stable throughout the study in the normal saline and NAC groups (F (1.95, 37.1=0.67, P=0.513. The peak airway pressure did not change significantly during the study in the normal saline and NAC groups (F (1.52, 56.4=0.91, P=0.384. Conclusion: Considering the limitations of the study, nebulized NAC in mechanically ventilated patients was not effective more than normal saline nebulization in reducing the density of mucous plugs. The peak and plateau airway pressures were relatively stable throughout the study in both groups. Trial Registration Number: IRCT201104276312N1.

  15. Molecular mechanisms involved in casein gene expression and secretion in mouse mammary epithelial cells

    International Nuclear Information System (INIS)

    Lee, E.Y.H.P.; Lee, W.H.; Parry, G.; Bissell, M.J.

    1985-01-01

    Mouse mammary epithelial cells (MMEC) secrete a group of milk-specific proteins including various caseins and whey proteins. Dissociated mammary epithelial cells maintain expression of most of their differentiated functions only if cells are plated on a suitable substratum. Casein production and section, cell morphology, and production of α-lactalbumin have been used as markers to assess the degree of differentiation of mammary cells in culture. The general consensus is that cells express their differentiated properties at high levels and for longer periods of time on such substrata. In this paper, the authors demonstrate that modulation of the expression of caseins by floating collagen gels is manifested at several regulatory points

  16. Immunoglobins in mammary secretions

    DEFF Research Database (Denmark)

    Hurley, W L; Theil, Peter Kappel

    2013-01-01

    Immunoglobulins secreted in colostrum and milk by the lactating mammal are major factors providing immune protection to the newborn. Immunoglobulins in mammary secretions represent the cumulative immune response of the lactating animal to exposure to antigenic stimulation that occurs through...... the immunoglobulins found in mammary secretions in the context of their diversity of structure, origin, mechanisms of transfer, and function....

  17. Altered insulin and glucagon secretion in treated genetic hyperlipemia: a mechanism of theraphy?

    Science.gov (United States)

    Eaton, R P; Oase, R; Schade, D S

    1976-03-01

    The influence of Halofenate therapy on insulin and glucagon secretion was examined in the Zucker rat with genetic endogenous hyperlipemia. Coincident with the lipid lowering effects of Halofenate, the net change in the basal bihormonal axis favored glucagon, with the I/G molar ratio (Insulin/Glucagon) decreasing from 2.72 +/- 0.53 to 0.96 +/- 0.20 during treatment with this drug. Following arginine stimulation the I/G ratio remained reduced at 0.87 +/- 0.13 in Halofenate treated animals, contrasting with the statistically greater ratio of 2.5 +/- 0.55 in control animals. The Halofenate induced state of reduced insulin:glucagon was associated with hypolipemia, postarginine hyperglycemia, and hyperketonemia,-three metabolic parameters characteristic of glucagon excess relative to insulin. It is suggested that the lipid-lowering action of Halofenate in genetic hyperlipemia may reflect the altered bihormonal axis induced by the drug.

  18. RTX proteins: a highly diverse family secreted by a common mechanism

    Czech Academy of Sciences Publication Activity Database

    Linhartová, Irena; Bumba, Ladislav; Mašín, Jiří; Basler, Marek; Osička, Radim; Kamanová, Jana; Procházková, Kateřina; Adkins, Irena; Hejnová-Holubová, Jana; Sadílková, Lenka; Morová, Jana; Šebo, Peter

    2010-01-01

    Roč. 34, č. 6 (2010), s. 1076-1112 ISSN 0168-6445 R&D Projects: GA AV ČR IAA500200914; GA MŠk 2B06161; GA MŠk 1M0506; GA AV ČR KAN200520702; GA ČR GA310/08/0447; GA ČR GP310/09/P582; GA ČR GP310/07/P115; GA ČR GP204/07/P105 Institutional research plan: CEZ:AV0Z50200510; CEZ:AV0Z50520701 Keywords : bacterial toxin * type I secretion system * RTX locus Subject RIV: EE - Microbiology, Virology Impact factor: 11.796, year: 2010

  19. Glucose stimulates neurotensin secretion from the rat small intestine by mechanisms involving SGLT1 and GLUT2 leading to cell depolarization and calcium influx

    DEFF Research Database (Denmark)

    Kuhre, Rune Ehrenreich; Bechmann, Louise Ellegaard; Hartmann, Bolette

    2015-01-01

    Neurotensin (NT) is a neurohormone produced in the central nervous system and in the gut epithelium by the enteroendocrine N cell. NT may play a role in appetite regulation and may have potential in obesity treatment. Glucose ingestion stimulates NT secretion in healthy young humans......, but the mechanisms involved are not well understood. Here, we show that rats express NT in the gut and that glucose gavage stimulates secretion similarly to oral glucose in humans. Therefore, we conducted experiments on isolated perfused rat small intestine with a view to characterize the cellular pathways...... of secretion. Luminal glucose (20% wt/vol) stimulated secretion but vascular glucose (5, 10, or 15 mmol/l) was without effect. The underlying mechanisms depend on membrane depolarization and calcium influx, since the voltage-gated calcium channel inhibitor nifedipine and the KATP channel opener diazoxide...

  20. Hypermethylations of RASAL1 and KLOTHO is associated with renal dysfunction in a Chinese population environmentally exposed to cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Chen; Liang, Yihuai [School of Public Health, Fudan University, 130 DongAn Road, Shanghai 200032 (China); Key Laboratory of Public Health Safety, Ministry of Education, 130 DongAn Road, Shanghai 200032 (China); Lei, Lijian [Department of Epidemiology, School of Public Health, Shanxi Medical University, Shanxi (China); Zhu, Guoying; Chen, Xiao [Department of Bone Metabolism, Institute of Radiation Medicine, Fudan University, Shanghai (China); Jin, Taiyi, E-mail: tyjin@shmu.edu.cn [School of Public Health, Fudan University, 130 DongAn Road, Shanghai 200032 (China); Key Laboratory of Public Health Safety, Ministry of Education, 130 DongAn Road, Shanghai 200032 (China); Wu, Qing, E-mail: qingwu@fudan.edu.cn [School of Public Health, Fudan University, 130 DongAn Road, Shanghai 200032 (China); Key Laboratory of Public Health Safety, Ministry of Education, 130 DongAn Road, Shanghai 200032 (China)

    2013-08-15

    Exposure to cadmium (Cd) can affect both DNA methylation and renal function, but there are few examples of the association between epigenetic markers and Cd-induced kidney damage. It has been suggested that hypermethylation of the genes RASAL1 and KLOTHO is associated with renal fibrogenesis. To investigate whether hypermethylation of RASAL1 and KLOTHO in peripheral blood DNA can be associated with Cd exposure and/or Cd-induced renal dysfunction, the degrees of methylation of RASAL1 and KLOTHO in peripheral blood DNA from 81 residents in Cd-polluted and non-polluted areas were measured using bisulfate-PCR-pyrosequencing. Changes in blood cadmium (BCd), urinary cadmium (UCd), and kidney parameters were measured, and the glomerular filtration rate (eGFR) was estimated. The levels of BCd and UCd correlated positively with the levels of DNA methylation in RASAL1 and in KLOTHO. The more heavily exposed residents (BCd, 4.23–13.22 μg/L; UCd, 8.65–32.90 μg/g creatinine) exhibited obvious renal dysfunction. Notably, when Cd concentration in blood and urine was adjusted, the increased methylation level in RASAL1 was inversely correlated with eGFR (P < 0.01) but the relationship between hypermethylation of KLOTHO and eGFR was not statistically significant. The methylation of RASAL1 increased along with the increased abnormal prevalence of eGFR. Our findings suggest that Cd exposure can induce the hypermethylation of RASAL1 and KLOTHO. Hypermethylation of RASAL1 may be an indicator of the progress for chronic kidney disease. - Highlights: • A long term heavily Cd exposure induced renal dysfunction. • Cd exposure correlated positively with DNA methylation in RASAL1 and KLOTHO. • Hypermethylation of RASAL1 correlated with adjusted renal function indicators.

  1. Spironolactone ameliorates PIT1-dependent vascular osteoinduction in klotho-hypomorphic mice.

    Science.gov (United States)

    Voelkl, Jakob; Alesutan, Ioana; Leibrock, Christina B; Quintanilla-Martinez, Leticia; Kuhn, Volker; Feger, Martina; Mia, Sobuj; Ahmed, Mohamed S E; Rosenblatt, Kevin P; Kuro-O, Makoto; Lang, Florian

    2013-02-01

    Klotho is a potent regulator of 1,25-hydroxyvitamin D3 [1,25(OH)2D3] formation and calcium-phosphate metabolism. Klotho-hypomorphic mice (kl/kl mice) suffer from severe growth deficits, rapid aging, hyperphosphatemia, hyperaldosteronism, and extensive vascular and soft tissue calcification. Sequelae of klotho deficiency are similar to those of end-stage renal disease. We show here that the mineralocorticoid receptor antagonist spironolactone reduced vascular and soft tissue calcification and increased the life span of kl/kl mice, without significant effects on 1,25(OH)2D3, FGF23, calcium, and phosphate plasma concentrations. Spironolactone also reduced the expression of osteoinductive Pit1 and Tnfa mRNA, osteogenic transcription factors, and alkaline phosphatase (Alpl) in calcified tissues of kl/kl mice. In human aortic smooth muscle cells (HAoSMCs), aldosterone dose-dependently increased PIT1 mRNA expression, an effect paralleled by increased expression of osteogenic transcription factors and enhanced ALP activity. The effects of aldosterone were reversed by both spironolactone treatment and PIT1 silencing and were mitigated by FGF23 cotreatment in HAoSMCs. In conclusion, aldosterone contributes to vascular and soft tissue calcification, an effect due, at least in part, to stimulation of spironolactone-sensitive, PIT1-dependent osteoinductive signaling.

  2. Fibroblast growth factor 23 and soluble klotho in children with chronic kidney disease.

    Science.gov (United States)

    Wan, Mandy; Smith, Colette; Shah, Vanita; Gullet, Ambrose; Wells, David; Rees, Lesley; Shroff, Rukshana

    2013-01-01

    Fibroblast growth factor 23 (FGF23), a bone-derived phosphaturic hormone, is elevated in chronic kidney disease (CKD). There are scarce data on the levels of its essential co-receptor klotho, and longitudinal changes in FGF23 levels are also unknown. We examined FGF23 and soluble klotho (s-klotho) levels over 1 year in 154 children with CKD Stages 1-5 (CKD1-5), were on dialysis or who have received a transplantation. In children with CKD1-5 and who were receiving dialysis, FGF23 correlated inversely with the estimated glomerular filtration rate (eGFR) (P children with eGFR of 15-29 mL/min/1.73 m(2), with an overall 5% annual increase in the CKD1-5 and dialysis cohort. High FGF23 levels were seen with high calcium (Ca) levels (P children with well-controlled P levels. Novel associations between FGF23 and serum Ca as well as 25(OH)D warrant further investigation.

  3. Bicarbonate-sensitive calcification and lifespan of klotho-deficient mice.

    Science.gov (United States)

    Leibrock, Christina B; Voelkl, Jakob; Kohlhofer, Ursula; Quintanilla-Martinez, Leticia; Kuro-O, Makoto; Lang, Florian

    2016-01-01

    Klotho, a protein counteracting aging, is a powerful inhibitor of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] formation and regulator of mineral metabolism. In klotho hypomorphic (kl/kl) mice, excessive 1,25(OH)2D3 formation leads to hypercalcemia, hyperphosphatemia and vascular calcification, severe growth deficits, accelerated aging and early death. Kl/kl mice further suffer from extracellular volume depletion and hypotension, leading to the stimulation of antidiuretic hormone and aldosterone release. A vitamin D-deficient diet, restriction of dietary phosphate, inhibition of mineralocorticoid receptors with spironolactone, and dietary NaCl all extend the lifespan of kl/kl mice. Kl/kl mice suffer from acidosis. The present study explored whether replacement of tap drinking water by 150 mM NaHCO3 affects the growth, tissue calcification, and lifespan of kl/kl mice. As a result, NaHCO3 administration to kl/kl mice did not reverse the growth deficit but substantially decreased tissue calcification and significantly increased the average lifespan from 78 to 127 days. NaHCO3 did not significantly affect plasma concentrations of 1,25(OH)2D3 and Ca(2+) but significantly decreased plasma phosphate concentration and plasma aldosterone concentration. The present study reveals a novel effect of bicarbonate, i.e., a favorable influence on vascular calcification and early death of klotho-deficient mice. Copyright © 2016 the American Physiological Society.

  4. Thermodynamic secrets of multidrug resistance: A new take on transport mechanisms of secondary active antiporters.

    Science.gov (United States)

    Zhang, Xuejun C; Liu, Min; Lu, Guangyuan; Heng, Jie

    2018-03-01

    Multidrug resistance (MDR) presents a growing challenge to global public health. Drug extrusion transporters play a critical part in MDR; thus, their mechanisms of substrate recognition are being studied in great detail. In this work, we review common structural features of key transporters involved in MDR. Based on our membrane potential-driving hypothesis, we propose a general energy-coupling mechanism for secondary-active antiporters. This putative mechanism provides a common framework for understanding poly-specificity of most-if not all-MDR transporters. © 2017 The Protein Society.

  5. The molecular mechanism of leptin secretion and expression induced by aristolochic acid in kidney fibroblast.

    Directory of Open Access Journals (Sweden)

    Tsung-Chieh Lin

    Full Text Available BACKGROUND: Leptin is a peptide hormone playing pivotal role in regulating food intake and energy expenditure. Growing evidence has suggested the pro-inflammatory and fibrogenic properties of leptin. In addition, patients with renal fibrosis have higher level of plasma leptin, which was due to the increased leptin production. Aristolochic acid (AA is a botanical toxin characterized to associate with the development of renal fibrosis including tubulointerstitial fibrosis. However, whether leptin is upregulated to participate in AA-induced kidney fibrosis remain completely unknown. METHODOLOGY/PRINCIPAL FINDINGS: In this study, leptin expression was increased by sublethal dose of AA in kidney fibroblast NRK49f determined by enzyme-linked immunosorbent assay and Western blot. Data from real-time reverse transcriptase-polymerase chain reaction revealed that leptin was upregulated by AA at transcriptional level. DNA binding activity of CCAAT enhancer binding protein α (C/EBP α, one of the transcription factors for leptin gene, was enhanced in DNA affinity precipitation assay and chromatin immunoprecipitation experiments. Knockdown of C/EBP α expression by small interfering RNA markedly reduced AA-induced leptin expression. Moreover, AA promoted Akt interaction with p-PDK1, and increased phosphorylated activation of Akt. Akt knockdown, and inhibition of Akt signaling by LY294002 and mTOR inhibitor rapamycin reduced leptin expression. Furthermore, treatment of LY294002 or rapamycin significantly suppressed AA-induced C/EBP α DNA-binding activity. These results suggest that Akt and C/EBP α activation were involved in AA-regulated leptin expression. CONCLUSIONS/SIGNIFICANCE: Our findings demonstrate the first that AA could induce secretion and expression of fibrogenic leptin in kidney fibroblasts, which reveal potential involvement of leptin in the progression of kidney fibrosis in aristolochic acid nephropathy.

  6. Cellular mechanism underlying formaldehyde-stimulated Cl- secretion in rat airway epithelium.

    Directory of Open Access Journals (Sweden)

    Yu-Li Luo

    Full Text Available BACKGROUND: Recent studies suggest that formaldehyde (FA could be synthesized endogeneously and transient receptor potential (TRP channel might be the sensor of FA. However, the physiological significance is still unclear. METHODOLOGY/PRINCIPAL FINDINGS: The present study investigated the FA induced epithelial Cl(- secretion by activation of TRPV-1 channel located in the nerve ending fiber. Exogenously applied FA induced an increase of I(SC in intact rat trachea tissue but not in the primary cultured epithelial cells. Western blot and immunofluorescence analysis identified TRPV-1 expression in rat tracheal nerve ending. Capsazepine (CAZ, a TRPV-1 specific antagonist significantly blocked the I(SC induced by FA. The TRPV-1 agonist capsaicin (Cap induced an increase of I(SC, which was similar to the I(SC induced by FA. L-703606, an NK-1 specific inhibitor and propranolol, an adrenalin β receptor inhibitor significantly abolished the I(SC induced by FA or Cap. In the ion substitute analysis, FA could not induce I(SC in the absence of extracelluar Cl(-. The I(SC induced by FA could be blocked by the non-specific Cl(- channel inhibitor DPC and the CFTR specific inhibitor CFTR(i-172, but not by the Ca(2+-activated Cl(- channel inhibitor DIDS. Furthermore, both forskolin, an agonist of adenylate cyclase (AC and MDL-12330A, an antagonist of AC could block FA-induced I(SC. CONCLUSION: Our results suggest that FA-induced epithelial I(SC response is mediated by nerve, involving the activation of TRPV-1 and release of adrenalin as well as substance P.

  7. Flying at no mechanical energy cost: disclosing the secret of wandering albatrosses.

    Directory of Open Access Journals (Sweden)

    Gottfried Sachs

    Full Text Available Albatrosses do something that no other birds are able to do: fly thousands of kilometres at no mechanical cost. This is possible because they use dynamic soaring, a flight mode that enables them to gain the energy required for flying from wind. Until now, the physical mechanisms of the energy gain in terms of the energy transfer from the wind to the bird were mostly unknown. Here we show that the energy gain is achieved by a dynamic flight manoeuvre consisting of a continually repeated up-down curve with optimal adjustment to the wind. We determined the energy obtained from the wind by analysing the measured trajectories of free flying birds using a new GPS-signal tracking method yielding a high precision. Our results reveal an evolutionary adaptation to an extreme environment, and may support recent biologically inspired research on robotic aircraft that might utilize albatrosses' flight technique for engineless propulsion.

  8. Flying at no mechanical energy cost: disclosing the secret of wandering albatrosses.

    Science.gov (United States)

    Sachs, Gottfried; Traugott, Johannes; Nesterova, Anna P; Dell'Omo, Giacomo; Kümmeth, Franz; Heidrich, Wolfgang; Vyssotski, Alexei L; Bonadonna, Francesco

    2012-01-01

    Albatrosses do something that no other birds are able to do: fly thousands of kilometres at no mechanical cost. This is possible because they use dynamic soaring, a flight mode that enables them to gain the energy required for flying from wind. Until now, the physical mechanisms of the energy gain in terms of the energy transfer from the wind to the bird were mostly unknown. Here we show that the energy gain is achieved by a dynamic flight manoeuvre consisting of a continually repeated up-down curve with optimal adjustment to the wind. We determined the energy obtained from the wind by analysing the measured trajectories of free flying birds using a new GPS-signal tracking method yielding a high precision. Our results reveal an evolutionary adaptation to an extreme environment, and may support recent biologically inspired research on robotic aircraft that might utilize albatrosses' flight technique for engineless propulsion.

  9. Xenoestrogens modulate vascular endothelial growth factor secretion in breast cancer cells through an estrogen receptor-dependent mechanism.

    Science.gov (United States)

    Buteau-Lozano, Hélène; Velasco, Guillaume; Cristofari, Monique; Balaguer, Patrick; Perrot-Applanat, Martine

    2008-02-01

    Environmental chemicals may affect human health by disrupting endocrine function. Their possible role in the mammary gland and breast tumors is still unknown. Previous studies have demonstrated that vascular endothelial growth factor (VEGF), a key factor in angiogenesis and tumor progression, is an estrogen-regulated gene. We analyzed whether VEGF expression is regulated by different xenoestrogens in several breast cancer cells, MELN (derived from MCF-7) and MELP (derived from MDA-MB-231) and stably expressing estrogen receptor alpha (ERalpha); these cell lines stably express estrogen response element (beta-globin)-luciferase. Genistein, bisphenol A (BPA), 4-(tert-octyl)phenol (OP), dieldrin, and several phthalates, including benzyl butyl phthalate (BBP) and di-ethyl-2-hexyle phthalate (DEHP), were first shown to be estrogenic. These compounds induced a dose-dependent increase of VEGF secretion in MELN and MCF-7 cells; maximal effect was observed at 1-10 microM non-cytotoxic concentrations and was inhibited by the antiestrogen ICI 182 780. VEGF increase was not observed in ERalpha-negative MDA-MB-231 cells. Most substances increased VEGF transcript levels in MELN cells. In contrast, gamma-hexachlorocyclohexane, vinclozolin, and the phthalates (mono-n-butyl ester phthalic acid, di-isononyle phthalate, and di-isodecyle phthalate) were ineffective on both VEGF secretion and estrogenic luciferase induction in these cell lines. Specific kinase inhibitors PD98059, SB203580, or LY294002 suppressed the xenoestrogen-induced VEGF response, suggesting activation of MEK, p38 kinase, and phosphatidylinositol-3-kinase pathways. Our in vitro results show for the first time that genistein and xenoestrogens (BPA, OP, dieldrin, BBP, and DEHP at high concentrations) up-regulate VEGF expression in MELN cells by an ER-dependent mechanism. Since VEGF increases capillary permeability and breast tumor angiogenesis in vivo, the physiological relevance of these findings is discussed.

  10. Cholestasis: The ABCs of Cellular Mechanisms for Impaired Bile Secretion – Transporters and Genes

    Directory of Open Access Journals (Sweden)

    Eldon A Shaffer

    2002-01-01

    Full Text Available The transport of bile salts, organic anions and cations, bilirubin and other substances from the portal blood into the biliary system is accomplished through the action of an array of transporter proteins in the hepatocyte. Transporters on the basolateral membrane, which faces the space of Disse, are responsible for the uptake of bile salts and organic anions. Once translocated through the hepatocyte to the canalicular membrane, other ATP pumps provide the energy to export bile salts, phospholipids and organic ions into the bile. Canalicular transport is rate limiting. Defects in specific canalicular transporters are responsible for many of the intrahepatic cholestatic syndromes that occur in children and adults. Moreover, cholestasis provokes changes in several transport mechanisms, many of which appear to be compensatory and serve to protect the liver from the toxic effects of accumulated materials. The identification and characterization of the major transporters responsible for bile formation have yielded a more precise classification of the cholestatic syndromes of infancy and childhood, and are unlocking the molecular mechanism of acquired cholestasis in adults. This review identifies the basic physiology of bile production and the actions of the key transporters, indicates the clinical relevance and possible treatments of transport disorders, and provides an illustrative case.

  11. The structure and molecular mechanics calculations of the cyclic (1 → 2)-β- D-glucan secreted by Rhizobium tropici CIAT 899

    Science.gov (United States)

    Gil Serrano, Antonio M.; Franco-Rodríguez, Guillermo; González-Jiménez, Isabel; Tejero-Mateo, Pilar; Molina, José Molina; Dobado, J. A.; Megías, Manuel; Romero, Maria Jesús

    1993-12-01

    The structure of the extracellular cyclic (1 → 2)-β- D-glucan secreted by Rhizobium tropici CIAT 899 has been studied by methylation analysis, 1D and 2D NMR experiments, HPLC and FAB-MS. Molecular mechanics (MM2) and theoretical 3JHH coupling constants calculations were performed.

  12. Membrane Cholesterol Removal Changes Mechanical Properties of Cells and Induces Secretion of a Specific Pool of Lysosomes

    Science.gov (United States)

    Roma, Paula Magda S.; Alves, Ana Paula; Rocha, Carolina D.; Valverde, Thalita M.; Aguiar, Pedro Henrique N.; Almeida, Fernando P.; Guimarães, Allan J.; Guatimosim, Cristina; Silva, Aristóbolo M.; Fernandes, Maria C.; Andrews, Norma W.; Viana, Nathan B.; Mesquita, Oscar N.; Agero, Ubirajara; Andrade, Luciana O.

    2013-01-01

    In a previous study we had shown that membrane cholesterol removal induced unregulated lysosomal exocytosis events leading to the depletion of lysosomes located at cell periphery. However, the mechanism by which cholesterol triggered these exocytic events had not been uncovered. In this study we investigated the importance of cholesterol in controlling mechanical properties of cells and its connection with lysosomal exocytosis. Tether extraction with optical tweezers and defocusing microscopy were used to assess cell dynamics in mouse fibroblasts. These assays showed that bending modulus and surface tension increased when cholesterol was extracted from fibroblasts plasma membrane upon incubation with MβCD, and that the membrane-cytoskeleton relaxation time increased at the beginning of MβCD treatment and decreased at the end. We also showed for the first time that the amplitude of membrane-cytoskeleton fluctuation decreased during cholesterol sequestration, showing that these cells become stiffer. These changes in membrane dynamics involved not only rearrangement of the actin cytoskeleton, but also de novo actin polymerization and stress fiber formation through Rho activation. We found that these mechanical changes observed after cholesterol sequestration were involved in triggering lysosomal exocytosis. Exocytosis occurred even in the absence of the lysosomal calcium sensor synaptotagmin VII, and was associated with actin polymerization induced by MβCD. Notably, exocytosis triggered by cholesterol removal led to the secretion of a unique population of lysosomes, different from the pool mobilized by actin depolymerizing drugs such as Latrunculin-A. These data support the existence of at least two different pools of lysosomes with different exocytosis dynamics, one of which is directly mobilized for plasma membrane fusion after cholesterol removal. PMID:24376622

  13. Growth Hormone-Releaser Diet Attenuates Cognitive Dysfunction in Klotho Mutant Mice via Insulin-Like Growth Factor-1 Receptor Activation in a Genetic Aging Model

    Directory of Open Access Journals (Sweden)

    Seok Joo Park

    2014-09-01

    Full Text Available BackgroundIt has been recognized that a defect in klotho gene expression accelerates the degeneration of multiple age-sensitive traits. Accumulating evidence indicates that aging is associated with declines in cognitive function and the activity of growth hormone (GH/insulin-like growth factor-1 (IGF-1.MethodsIn this study, we examined whether a GH-releaser diet could be effective in protecting against cognitive impairment in klotho mutant mice.ResultsThe GH-releaser diet significantly induced the expression of IGF-1 and IGF-1 receptors in the hippocampus of klotho mutant mice. Klotho mutant mice showed significant memory impairments as compared with wild-type mice. In addition, the klotho mutation significantly decreased the expression of cell survival/antiapoptotic factors, including phospho-Akt (p-Akt/phospho-glycogen synthase kinase3β (p-GSK3β, phospho-extracellular signal-related kinase (p-ERK, and Bcl-2, but significantly increased those of cell death/proapoptotic factors, such as phospho-c-jun N-terminal kinase (p-JNK, Bax, and cleaved caspase-3 in the hippocampus. Treatment with GH-releaser diet significantly attenuated both decreases in the expression of cell survival/antiapoptotic factors and increases in the expression of cell death/proapoptotic factors in the hippocampus of klotho mutant mice. In addition, klotho mutation-induced oxidative stress was significantly attenuated by the GH-releaser diet. Consequently, a GH-releaser diet significantly improved memory function in the klotho mutant mice. GH-releaser diet-mediated actions were significantly reversed by JB-1, an IGF-1 receptor antagonist.ConclusionThe results suggest that a GH-releaser diet attenuates oxidative stress, proapoptotic changes and consequent dysfunction in klotho mutant mice by promoting IGF-1 expression and IGF-1 receptor activation.

  14. Genetic Variants in KLOTHO Associate With Cognitive Function in the Oldest Old Group

    DEFF Research Database (Denmark)

    Mengel-From, Jonas; Sørensen, Mette; Nygaard, Marianne

    2016-01-01

    Decline in cognitive abilities is a major concern in aging individuals. A potential important factor for functioning of the central nervous system in late-life stages is the KLOTHO (KL) gene. KL is expressed in various organs including the brain and is involved in multiple biological processes......, for example, growth factor signaling. In the present study, 19 tagging gene variants in KL were studied in relation to 2 measures of cognitive function, a 5-item cognitive composite score and the Mini Mental State Examination, in 1,480 Danes 92-100 years of age. We found that heterozygotes for the previously...

  15. Mechanisms of estradiol-induced insulin secretion by the G protein-coupled estrogen receptor GPR30/GPER in pancreatic beta-cells.

    Science.gov (United States)

    Sharma, Geetanjali; Prossnitz, Eric R

    2011-08-01

    Sexual dimorphism and supplementation studies suggest an important role for estrogens in the amelioration of glucose intolerance and diabetes. Because little is known regarding the signaling mechanisms involved in estradiol-mediated insulin secretion, we investigated the role of the G protein-coupled receptor 30, now designated G protein-coupled estrogen receptor (GPER), in activating signal transduction cascades in β-cells, leading to secretion of insulin. GPER function in estradiol-induced signaling in the pancreatic β-cell line MIN6 was assessed using small interfering RNA and GPER-selective ligands (G-1 and G15) and in islets isolated from wild-type and GPER knockout mice. GPER is expressed in MIN6 cells, where estradiol and the GPER-selective agonist G-1 mediate calcium mobilization and activation of ERK and phosphatidylinositol 3-kinase. Both estradiol and G-1 induced insulin secretion under low- and high-glucose conditions, which was inhibited by pretreatment with GPER antagonist G15 as well as depletion of GPER by small interfering RNA. Insulin secretion in response to estradiol and G-1 was dependent on epidermal growth factor receptor and ERK activation and further modulated by phosphatidylinositol 3-kinase activity. In islets isolated from wild-type mice, the GPER antagonist G15 inhibited insulin secretion induced by estradiol and G-1, both of which failed to induce insulin secretion in islets obtained from GPER knockout mice. Our results indicate that GPER activation of the epidermal growth factor receptor and ERK in response to estradiol treatment plays a critical role in the secretion of insulin from β-cells. The results of this study suggest that the activation of downstream signaling pathways by the GPER-selective ligand G-1 could represent a novel therapeutic strategy in the treatment of diabetes.

  16. Mechanisms of Estradiol-Induced Insulin Secretion by the G Protein-Coupled Estrogen Receptor GPR30/GPER in Pancreatic β-Cells

    Science.gov (United States)

    Sharma, Geetanjali

    2011-01-01

    Sexual dimorphism and supplementation studies suggest an important role for estrogens in the amelioration of glucose intolerance and diabetes. Because little is known regarding the signaling mechanisms involved in estradiol-mediated insulin secretion, we investigated the role of the G protein-coupled receptor 30, now designated G protein-coupled estrogen receptor (GPER), in activating signal transduction cascades in β-cells, leading to secretion of insulin. GPER function in estradiol-induced signaling in the pancreatic β-cell line MIN6 was assessed using small interfering RNA and GPER-selective ligands (G-1 and G15) and in islets isolated from wild-type and GPER knockout mice. GPER is expressed in MIN6 cells, where estradiol and the GPER-selective agonist G-1 mediate calcium mobilization and activation of ERK and phosphatidylinositol 3-kinase. Both estradiol and G-1 induced insulin secretion under low- and high-glucose conditions, which was inhibited by pretreatment with GPER antagonist G15 as well as depletion of GPER by small interfering RNA. Insulin secretion in response to estradiol and G-1 was dependent on epidermal growth factor receptor and ERK activation and further modulated by phosphatidylinositol 3-kinase activity. In islets isolated from wild-type mice, the GPER antagonist G15 inhibited insulin secretion induced by estradiol and G-1, both of which failed to induce insulin secretion in islets obtained from GPER knockout mice. Our results indicate that GPER activation of the epidermal growth factor receptor and ERK in response to estradiol treatment plays a critical role in the secretion of insulin from β-cells. The results of this study suggest that the activation of downstream signaling pathways by the GPER-selective ligand G-1 could represent a novel therapeutic strategy in the treatment of diabetes. PMID:21673097

  17. The Eicosapentaenoic Acid Metabolite 15-Deoxy-δ12,14-Prostaglandin J3 Increases Adiponectin Secretion by Adipocytes Partly via a PPARγ-Dependent Mechanism

    Science.gov (United States)

    Lefils-Lacourtablaise, Jennifer; Socorro, Mairobys; Géloën, Alain; Daira, Patricia; Debard, Cyrille; Loizon, Emmanuelle; Guichardant, Michel; Dominguez, Zury; Vidal, Hubert; Lagarde, Michel; Bernoud-Hubac, Nathalie

    2013-01-01

    The intake of ω-3 polyunsaturated fatty acids (PUFAs), which are abundant in marine fish meat and oil, has been shown to exert many beneficial effects. The mechanisms behind those effects are numerous, including interference with the arachidonic acid cascade that produces pro-inflammatory eicosanoids, formation of novel bioactive lipid mediators, and change in the pattern of secreted adipocytokines. In our study, we show that eicosapentaenoic acid (EPA) increases secreted adiponectin from 3T3-L1 adipocytes and in plasma of mice as early as 4 days after initiation of an EPA-rich diet. Using 3T3-L1 adipocytes, we report for the first time that 15-deoxy-δ12,14-PGJ3 (15d-PGJ3), a product of EPA, also increases the secretion of adiponectin. We demonstrate that the increased adiponectin secretion induced by 15d-PGJ3 is partially peroxisome proliferator-activated receptor-gamma (PPAR-γ)-mediated. Finally, we show that 3T3-L1 adipocytes can synthesize 15d-PGJ3 from EPA. 15d-PGJ3 was also detected in adipose tissue from EPA-fed mice. Thus, these studies provide a novel mechanism(s) for the therapeutic benefits of ω-3 polyunsaturated fatty acids dietary supplementation. PMID:23734181

  18. Upregulation of PRMT6 by LPS suppresses Klotho expression through interaction with NF-κB in glomerular mesangial cells.

    Science.gov (United States)

    Tsai, Kuen-Daw; Lee, Wen-Xi; Chen, Wei; Chen, Bo-Yu; Chen, Kuan-Lin; Hsiao, Tzu-Chia; Wang, Sue-Hong; Lee, Yi-Ju; Liang, Shan-Yuan; Shieh, Jia-Ching; Lin, Ting-Hui

    2018-04-01

    Lipopolysaccharide (LPS) released from gram-negative bacteria stimulates immune responses in infected cells. Epigenetic modifications such as DNA methylation and protein methylation modulate LPS-induced innate immune gene expressions. Expression of the Klotho protein decreased with LPS treatment in rats. In a cellular model, information regarding the effect of LPS on Klotho expression was meager. In the present study, we demonstrated that LPS triggered global DNA and protein methylation in glomerular mesangial MES-13 cells. LPS upregulated protein expressions of enzymes central to cellular methylation reactions, especially protein arginine methyltransferase 6 (PRMT6) in MES-13 cells. Expression of the Klotho protein was diminished by LPS and was restored by 5-Aza-2'-deoxycytidine (5-Aza-2'-dc), AMI-1, and ammonium pyrrolidinedithiocarbamate (PDTC), but not adenosine aldehyde (AdOx). NF-κB was identified as a substrate for arginine methylation and interacted with PRMT6 in MES-13 cells. Inhibition of PRMT activity by AMI-1 blocked LPS-induced NF-κB nuclear translocation in MES-13 cells. Our data indicate that NF-κB negatively regulated Klotho expression with an interaction with PRMT6, which was upregulated by LPS in MES-13 cells. © 2017 Wiley Periodicals, Inc.

  19. Genetic Ablation of Fgf23 or Klotho Does not Modulate Experimental Heart Hypertrophy Induced by Pressure Overload.

    Science.gov (United States)

    Slavic, Svetlana; Ford, Kristopher; Modert, Magalie; Becirovic, Amarela; Handschuh, Stephan; Baierl, Andreas; Katica, Nejla; Zeitz, Ute; Erben, Reinhold G; Andrukhova, Olena

    2017-09-12

    Left ventricular hypertrophy (LVH) ultimately leads to heart failure in conditions of increased cardiac pre- or afterload. The bone-derived phosphaturic and sodium-conserving hormone fibroblast growth factor-23 (FGF23) and its co-receptor Klotho have been implicated in the development of uremic LVH. Using transverse aortic constriction (TAC) in gene-targeted mouse models, we examine the role of Fgf23 and Klotho in cardiac hypertrophy and dysfunction induced by pressure overload. TAC profoundly increases serum intact Fgf23 due to increased cardiac and bony Fgf23 transcription and downregulation of Fgf23 cleavage. Aldosterone receptor blocker spironolactone normalizes serum intact Fgf23 levels after TAC by reducing bony Fgf23 transcription. Notably, genetic Fgf23 or Klotho deficiency does not influence TAC-induced hypertrophic remodelling, LV functional impairment, or LV fibrosis. Despite the profound, aldosterone-mediated increase in circulating intact Fgf23 after TAC, our data do not support an essential role of Fgf23 or Klotho in the pathophysiology of pressure overload-induced cardiac hypertrophy.

  20. Protective role of klotho protein on epithelial cells upon co-culture with activated or senescent monocytes

    Energy Technology Data Exchange (ETDEWEB)

    Mytych, Jennifer, E-mail: jennifermytych@gmail.com [Institute of Applied Biotechnology and Basic Sciences, University of Rzeszow, Werynia 502, 36-100 Kolbuszowa (Poland); Centre of Applied Biotechnology and Basic Sciences, University of Rzeszow, Werynia 502, 36-100 Kolbuszowa (Poland); Wos, Izabela; Solek, Przemyslaw; Koziorowski, Marek [Institute of Applied Biotechnology and Basic Sciences, University of Rzeszow, Werynia 502, 36-100 Kolbuszowa (Poland); Centre of Applied Biotechnology and Basic Sciences, University of Rzeszow, Werynia 502, 36-100 Kolbuszowa (Poland)

    2017-01-15

    Monocytes ensure proper functioning and maintenance of epithelial cells, while good condition of monocytes is a key factor of these interactions. Although, it was shown that in some circumstances, a population of altered monocytes may appear, there is no data regarding their effect on epithelial cells. In this study, using direct co-culture model with LPS-activated and Dox-induced senescent THP-1 monocytes, we reported for the first time ROS-induced DNA damage, reduced metabolic activity, proliferation inhibition and cell cycle arrest followed by p16-, p21- and p27-mediated DNA damage response pathways activation, premature senescence and apoptosis induction in HeLa cells. Also, we show that klotho protein possessing anti-aging and anti-inflammatory characteristics reduced cytotoxic and genotoxic events by inhibition of insulin/IGF-IR and downregulation of TRF1 and TRF2 proteins. Therefore, klotho protein could be considered as a protective factor against changes caused by altered monocytes in epithelial cells. - Highlights: • Activated and senescent THP-1 monocytes induced cyto- and genotoxicity in HeLa cells. • Altered monocytes provoked oxidative and nitrosative stress-induced DNA damage. • DNA damage activated DDR pathways and lead to premature senescence and apoptosis. • Klotho reduced ROS/RNS-mediated toxicity through insulin/IGF-IR pathway inhibition. • Klotho protects HeLa cells from cyto- and genotoxicity induced by altered monocytes.

  1. Impact of Food Components on in vitro Calcitonin Gene-Related Peptide Secretion-A Potential Mechanism for Dietary Influence on Migraine.

    Science.gov (United States)

    Slavin, Margaret; Bourguignon, Julia; Jackson, Kyle; Orciga, Michael-Angelo

    2016-07-01

    Calcitonin gene-related peptide (CGRP) is a pivotal messenger in the inflammatory process in migraine. Limited evidence indicates that diet impacts circulating levels of CGRP, suggesting that certain elements in the diet may influence migraine outcomes. Interruption of calcium signaling, a mechanism which can trigger CGRP release, has been suggested as one potential route by which exogenous food substances may impact CGRP secretion. The objective of this study was to investigate the effects of foods and a dietary supplement on two migraine-related mechanisms in vitro: CGRP secretion from neuroendocrine CA77 cells, and calcium uptake by differentiated PC12 cells. Ginger and grape pomace extracts were selected for their anecdotal connections to reducing or promoting migraine. S-petasin was selected as a suspected active constituent of butterbur extract, the migraine prophylactic dietary supplement. Results showed a statistically significant decrease in stimulated CGRP secretion from CA77 cells following treatment with ginger (0.2 mg dry ginger equivalent/mL) and two doses of grape pomace (0.25 and 1.0 mg dry pomace equivalent/mL) extracts. Relative to vehicle control, CGRP secretion decreased by 22%, 43%, and 87%, respectively. S-petasin at 1.0 μM also decreased CGRP secretion by 24%. Meanwhile, S-petasin and ginger extract showed inhibition of calcium influx, whereas grape pomace had no effect on calcium. These results suggest that grape pomace and ginger extracts, and S-petasin may have anti-inflammatory propensity by preventing CGRP release in migraine, although potentially by different mechanisms, which future studies may elucidate further.

  2. Transcription factor organic cation transporter 1 (OCT-1 affects the expression of porcine Klotho (KL gene

    Directory of Open Access Journals (Sweden)

    Yan Li

    2016-07-01

    Full Text Available Klotho (KL, originally discovered as an aging suppressor, is a membrane protein that shares sequence similarity with the β-glucosidase enzymes. Recent reports showed Klotho might play a role in adipocyte maturation and systemic glucose metabolism. However, little is known about the transcription factors involved in regulating the expression of porcine KL gene. Deletion fragment analysis identified KL-D2 (−418 bp to −3 bp as the porcine KL core promoter. MARC0022311SNP (A or G in KL intron 1 was detected in Landrace × DIV pigs using the Porcine SNP60 BeadChip. The pGL-D2-A and pGL-D2-G were constructed with KL-D2 and the intron fragment of different alleles and relative luciferase activity of pGL3-D2-G was significantly higher than that of pGL3-D2-A in the PK cells and ST cells. This was possibly the result of a change in KL binding ability with transcription factor organic cation transporter 1 (OCT-1, which was confirmed using electrophoretic mobility shift assays (EMSA and chromatin immune-precipitation (ChIP. Moreover, OCT-1 regulated endogenous KL expression by RNA interference experiments. Our study indicates SNP MARC0022311 affects porcine KL expression by regulating its promoter activity via OCT-1.

  3. Authentication Without Secrets

    Energy Technology Data Exchange (ETDEWEB)

    Pierson, Lyndon G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Robertson, Perry J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-11-01

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

  4. Association between light at night, melatonin secretion, sleep deprivation, and the internal clock: Health impacts and mechanisms of circadian disruption.

    Science.gov (United States)

    Touitou, Yvan; Reinberg, Alain; Touitou, David

    2017-03-15

    Exposure to Artificial Light At Night (ALAN) results in a disruption of the circadian system, which is deleterious to health. In industrialized countries, 75% of the total workforce is estimated to have been involved in shift work and night work. Epidemiologic studies, mainly of nurses, have revealed an association between sustained night work and a 50-100% higher incidence of breast cancer. The potential and multifactorial mechanisms of the effects include the suppression of melatonin secretion by ALAN, sleep deprivation, and circadian disruption. Shift and/or night work generally decreases the time spent sleeping, and it disrupts the circadian time structure. In the long run, this desynchronization is detrimental to health, as underscored by a large number of epidemiological studies that have uncovered elevated rates of several diseases, including cancer, diabetes, cardiovascular risks, obesity, mood disorders and age-related macular degeneration. It amounts to a public health issue in the light of the very substantial number of individuals involved. The IARC has classified shift work in group 2A of "probable carcinogens to humans" since "they involve a circadian disorganization". Countermeasures to the effects of ALAN, such as melatonin, bright light, or psychotropic drugs, have been proposed as a means to combat circadian clock disruption and improve adaptation to shift and night work. We review the evidence for the ALAN impacts on health. Furthermore, we highlight the importance of an in-depth mechanistic understanding to combat the detrimental properties of exposure to ALAN and develop strategies of prevention. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Residual oil fly ash induces cytotoxicity and mucin secretion by guinea pig tracheal epithelial cells via an oxidant-mediated mechanism.

    Science.gov (United States)

    Jiang, N; Dreher, K L; Dye, J A; Li, Y; Richards, J H; Martin, L D; Adler, K B

    2000-03-15

    Inhalation of ambient air particulate matter (PM) is associated with pulmonary injury and inflammation. Using primary cultures of guinea pig tracheal epithelial (GPTE) cells as an in vitro model of airway epithelium, we examined effects of exposure to suspensions of six different emission and ambient air PM samples: residual oil fly ash (ROFA) from an electrical power plant; fly ash from a domestic oil burning furnace (DOFA); ambient air dust from St. Louis (STL), Ottawa (OT), and Washington, DC (WDC); and volcanic ash from the eruption of Mount Saint Helens (MSH) in 1980. Effects of these particulates on cell viability (assessed via LDH assay), secretion of mucin (measured by a monoclonal antibody-based ELISA), and steady-state mRNA levels of the mucin gene MUC2 were determined. ROFA was the most toxic of the dusts tested, as it significantly increased LDH release following a 24-h incubation with 50 microg/cm(2) ROFA. ROFA also enhanced MUC2 mRNA after 4-h exposure, and mucin secretion after 8 h. ROFA-induced mucin secretion and cytotoxicity were attenuated by the oxidant scavenger, dimethylthiourea (DMTU). ROFA exposure also depleted cells of glutathione (GSH). Relatedly, depletion of intracellular GSH by treatment of the cells with buthionine sulfoxamine (BSO) also provoked mucin secretion, as well as enhancing the secretory effect of ROFA when the two agents were added together. L-NMA, the nitric oxide synthase (NOS) inhibitor, did not affect ROFA-induced mucin secretion. Of the soluble transition metals in ROFA (nickel, iron, vanadium), only vanadium individually, or combinations of the metals containing vanadium, provoked secretion. The results suggest ROFA enhances mucin secretion and generates toxicity in vitro to airway epithelium via a mechanism(s) involving generation of oxidant stress, perhaps related to depletion of cellular antioxidant capacity. Deleterious effects of inhalation of ROFA in the respiratory tract in vivo may relate to these cellular

  6. The Mapleson C circuit clears more secretions than the Laerdal circuit during manual hyperinflation in mechanically-ventilated patients: a randomised cross-over trial.

    Science.gov (United States)

    Hodgson, Carol; Ntoumenopoulos, George; Dawson, Heather; Paratz, Jennifer

    2007-01-01

    What is the effect of the Mapleson C circuit compared with the Laerdal circuit in removing secretions and improving ventilation and gas exchange during manual hyperinflation? Prospective, randomised, cross-over trial. Twenty patients from a tertiary-level intensive care unit who were being mechanically ventilated. Manual hyperinflation in side-lying with both the Mapleson C or Laerdal circuit on the one day, one circuit in the morning and one in the afternoon, with a washout period of at least three hours between them. Secretion clearance was measured as sputum weight, ventilation was measured as respiratory compliance and tidal volume, while gas exchange was measured as oxygenation and CO2 removal. The Mapleson C circuit cleared 0.89 g (95% CI 0.80 to 1.15) more secretions than the Laerdal circuit (p Mapleson C and the Laerdal circuits on respiratory compliance (p = 0.81), tidal volume (p = 0.45), oxygenation (p = 0.28), or CO2 removal (p = 0.17). Although more secretions were cleared using the Mapleson C compared with the Laerdal circuit in this study, this had no consequence in terms of oxygenation and compliance only trended to improve. As the study was underpowered the clinical significance of these findings is not clear.

  7. The impact of uropygial gland secretions on mechanically induced wearing of barn owl and pigeon body feathers

    Science.gov (United States)

    Ott, Benjamin; Müsse, Annika; Wagner, Hermann

    2016-04-01

    Bird feathers are remarkable structures light but yet durable providing insulation and the ability of flight. Owls are highly specialized birds of prey, widely known for their ability to y silently which is enabled by (micro-) structural specializations of the feathers. The barn owl replaces feathers less frequently in comparison to other same sized birds like pigeons, indicating a much better resistance against material fatigue of these delicate microstructures. We used axisymmetric drop shape analysis (ADSA) of water drop contact angles as a non-destructive method of characterizing wearing processes in feathers. We hypothesized that feathers become more wettable when worn. We also investigated the impact of ethanol treatment in order to remove fatty residues of the uropygial gland secretions, barn owls and pigeons use for preening, on ageing processes. Ethanol treatment resulted in a slight, but significant increase of water repellency in barn owl but not in pigeon flight feathers. Our preliminary data also suggest that the uropygial gland secretions decelerate the wearing process of the feather keratin. We observed this effect in both species, however, it was more distinct for barn owl uropygial gland secretions. The results of this study, obtained by contact angle measurements used as a non-destructive evaluation method of material fatigue, yield insights into the material fatigue of feathers and the decelerating effect of uropygial gland secretions on wear on the other hand.

  8. Mechanism of action of noradrenaline on secretion of progesterone and oxytocin by the bovine corpus luteum in vitro.

    Science.gov (United States)

    Miszkiel, G; Kotwica, J

    2001-01-01

    The present studies were conducted: (1) to determine which beta-adrenoceptor subtypes are involved in progesterone and oxytocin (OT) secretion, (2) to examine whether noradrenaline (NA) acts directly on the cytochrome P-450scc and 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD), and (3) to study the effect of prostaglandin F2 alpha (PGF2 alpha) on NA-stimulated steroidogenesis in luteal cells. The effect of NA on progesterone secretion from luteal slices of heifers on days 8-12 of the oestrous cycle was blocked by both atenolol (beta 1-antagonist) and ICI 118.551 hydrochloride (beta 2-antagonist). OT secretion was blocked only after treatment with ICI 118.551 hydrochloride (P salbutamol (10(-4)-10(-6) M), a selective beta 2 agonist, both increased progesterone production (P salbutamol at the dose of 10(-5) M (P < 0.01). Dobutamine had no effect on OT production at any dose. A stimulatory effect of NA on cytochrome P-450scc activity (P < 0.05) was demonstrated using 25-hydroxycholesterol as substrate. 3 beta-HSD activity also increased following NA (P < 0.01) or pregnenolone (P < 0.05) and in tissue treated with pregnenolone together with NA (P < 0.01). PGF decreased progesterone synthesis (P < 0.05) and 3 beta-HSD activity (P < 0.01) in tissue treated with NA. We conclude that NA stimulates progesterone secretion by luteal beta 1- and beta 2-adrenoceptors, while OT secretion is probably mediated only via the beta 2-receptor. NA also increases cytochrome P-450scc and 3 beta-HSD activity. PGF inhibits the luteotropic effect of NA on the luteal tissue.

  9. Diverse subpopulations of vesicles secreted by different intracellular mechanisms are present in exosome preparations obtained by differential ultracentrifugation

    Science.gov (United States)

    Bobrie, Angélique; Colombo, Marina; Krumeich, Sophie; Raposo, Graça; Théry, Clotilde

    2012-01-01

    Exosomes are extracellular vesicles of 50 to 100 nm in diameter, released by many cell types. Exosomes are formed inside the cell in intracellular endosomal compartments and are secreted upon fusion of these compartments with the plasma membrane. Cells also secrete other types of membrane vesicles, for instance, by outward budding from the plasma membrane, and although some of them clearly differ from exosomes by their structural features (larger size), others are possibly more difficult to separate. Here, using Rab27a inhibition to modulate exosome secretion, we show the existence of at least 2 distinct populations of vesicles after purification by classical ultracentrifugation from mouse tumor cell conditioned medium. Rab27a inhibition lead to decreased vesicular secretion of some conventional markers of exosomes (CD63, Tsg101, Alix and Hsc70) but did not affect secretion of others (CD9 and Mfge8). By electron microscopy, CD9 was observed on vesicles of various sizes, ranging from 30 nm to more than 150 nm in diameter. Flotation onto sucrose gradients showed different proportions of CD63, CD9 and Mfge8 not only in fractions of densities classically described for exosomes (around 1.15 g/ml) but also in fractions of densities over 1.20 g/ml, indicating the presence of heterogenous vesicle populations. CD9 and Mfge8 were also found in large vesicles pelleted at low speed and can thus not be considered as specific components of endosome-derived vesicles. We propose that the most commonly used protocols for exosome preparations co-purify vesicles from endosomal and other origins, possibly the plasma membrane. Future work will be required to improve techniques for accurate purification and characterization of the different populations of extracellular vesicles. PMID:24009879

  10. Ciguatoxin-induced catecholamine secretion in bovine chromaffin cells: mechanism of action and reversible inhibition by brevenal.

    Science.gov (United States)

    Nguyen-Huu, Truong D; Mattei, César; Wen, Peter J; Bourdelais, Andrea J; Lewis, Richard J; Benoit, Evelyne; Baden, Daniel G; Molgó, Jordi; Meunier, Frédéric A

    2010-10-01

    Ciguatoxin (P-CTX-1B) from the dinoflagellate Gambierdiscus toxicus, belongs to the family of polyether neurotoxins responsible for the neurological poisoning disorder ciguatera. Although it is the most widespread marine-borne disease affecting humans, there is no current FDA-approved treatment available except for symptomatic therapies. In this paper, we report that P-CTX-1B promotes catecholamine secretion from bovine chromaffin cells, an effect that is insensitive to concomitant activation of capacitative Ca(2+) entry. Moreover, we confirm that brevenal, a polyether from the dinoflagellate Karenia brevis, blocks P-CTX-1B-induced catecholamine secretion. This effect is partially reversible. Our results therefore raise the prospect of finding functional antagonists for P-CTX-1B that could be useful for the treatment of ciguatera. Copyright 2009 Elsevier Ltd. All rights reserved.

  11. Characterization of the Molecular Mechanisms Underlying Glucose Stimulated Insulin Secretion from Isolated Pancreatic β-cells Using Post-translational Modification Specific Proteomics (PTMomics)

    DEFF Research Database (Denmark)

    Kang, Taewook; Jensen, Pia; Huang, Honggang

    2018-01-01

    understanding of glucose-stimulated insulin secretion (GSIS) mechanisms under normal conditions is a prerequisite for developing better interventions against diabetes. Here, we aimed at identifying novel signaling pathways involved in the initial release of insulin from PBCs after glucose stimulation using......-cell interaction, cell movement, cell-ECM interaction and Focal Adhesion (e.g. integrins, semaphorins, and plexins) were found regulated at the level of sialylation, but not in protein expression. Collectively, we believe that this comprehensive Proteomics and PTMomics survey of signaling pathways taking place...

  12. Antimicrobial properties and death-inducing mechanisms of saccharomycin, a biocide secreted by Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Branco, Patrícia; Francisco, Diana; Monteiro, Margarida

    2017-01-01

    . cerevisiae strains also secrete natural biocide fractions during alcoholic fermentation, although at different levels, which correlates with the antagonistic effect exerted against non-Saccharomyces yeasts. We, therefore, term this biocide saccharomycin. The native AMPs were purified by gel......-filtration chromatography and its antimicrobial activity was compared to that exhibited by chemically synthesized analogues (AMP1 and AMP2/3). Results show that the antimicrobial activity of the native AMPs is significantly higher than that of the synthetic analogues (AMP1 and AMP2/3), but a conjugated action of the two...... species during alcoholic fermentations....

  13. Structure of the VipA/B Type VI Secretion Complex Suggests a Contraction-State-Specific Recycling Mechanism

    Directory of Open Access Journals (Sweden)

    Sebastian Kube

    2014-07-01

    Full Text Available The bacterial type VI secretion system is a multicomponent molecular machine directed against eukaryotic host cells and competing bacteria. An intracellular contractile tubular structure that bears functional homology with bacteriophage tails is pivotal for ejection of pathogenic effectors. Here, we present the 6 Å cryoelectron microscopy structure of the contracted Vibrio cholerae tubule consisting of the proteins VipA and VipB. We localized VipA and VipB in the protomer and identified structural homology between the C-terminal segment of VipB and the tail-sheath protein of T4 phages. We propose that homologous segments in VipB and T4 phages mediate tubule contraction. We show that in type VI secretion, contraction leads to exposure of the ClpV recognition motif, which is embedded in the type VI-specific four-helix-bundle N-domain of VipB. Disaggregation of the tubules by the AAA+ protein ClpV and recycling of the VipA/B subunits are thereby limited to the contracted state.

  14. Sustained Brown Fat Stimulation and Insulin Sensitization by a Humanized Bispecific Antibody Agonist for Fibroblast Growth Factor Receptor 1/βKlotho Complex

    Directory of Open Access Journals (Sweden)

    Ganesh Kolumam

    2015-07-01

    Full Text Available Dissipating excess calories as heat through therapeutic stimulation of brown adipose tissues (BAT has been proposed as a potential treatment for obesity-linked disorders. Here, we describe the generation of a humanized effector-less bispecific antibody that activates fibroblast growth factor receptor (FGFR 1/βKlotho complex, a common receptor for FGF21 and FGF19. Using this molecule, we show that antibody-mediated activation of FGFR1/βKlotho complex in mice induces sustained energy expenditure in BAT, browning of white adipose tissue, weight loss, and improvements in obesity-associated metabolic derangements including insulin resistance, hyperglycemia, dyslipidemia and hepatosteatosis. In mice and cynomolgus monkeys, FGFR1/βKlotho activation increased serum high-molecular-weight adiponectin, which appears to contribute over time by enhancing the amplitude of the metabolic benefits. At the same time, insulin sensitization by FGFR1/βKlotho activation occurs even before the onset of weight loss in a manner that is independent of adiponectin. Together, selective activation of FGFR1/βKlotho complex with a long acting therapeutic antibody represents an attractive approach for the treatment of type 2 diabetes and other obesity-linked disorders through enhanced energy expenditure, insulin sensitization and induction of high-molecular-weight adiponectin.

  15. Comparative proteome analysis of wild-type and klotho-knockout mouse kidneys using a combination of MALDI-IMS and LC-MS/MS.

    Science.gov (United States)

    Fujino, Yoko; Minamizaki, Tomoko; Hayashi, Ikue; Kawakami, Asako; Miyaji, Takaaki; Sakurai, Kaoru; Yoshioka, Hirotaka; Kozai, Katsuyuki; Okada, Mitsugi; Yoshiko, Yuji

    2017-07-01

    Mutation of the klotho gene in mice elicits a syndrome resembling accelerated human aging. However, there is limited evidence for the role of Klotho in the kidney. We conducted a comparative proteome analysis of wild-type (WT) and klotho-knockout (kl -/- ) mouse kidneys to identify proteins involved in Klotho deficiency. MALDI imaging MS (MALDI-IMS) of frozen kidney sections from 7-wk-old male WT and kl -/- mice was used to determine genotype-specific differences in the MS distribution. Proteins uniquely distributed in kl -/- kidneys were identified by subsequent analysis of adjacent trypsinized sections by MALDI-IMS in combination with LC-MS/MS. Immunohistochemistry and western blotting were adopted in qualitative and quantitation analysis. Ninety-seven and 69 proteins identified by LC-MS/MS were matched to the MALDI-IMS spectra in WT and kl -/- mouse kidneys, respectively. Among protein types matched, nucleic acid binding proteins were most abundant, followed by enzymes. We identified secretogranin-1 (SCG1), which was predominately distributed in the glomeruli and renal tubules of kl -/- mouse kidneys. Immunohistochemistry for SCG1 mirrored images of MALDI-IMS. SCG1 may be a candidate protein involved in Klotho deficiency. Although further research is needed to investigate the role of SCG1 in the kidney, we show the usefulness of MALDI-IMS combined with LC-MS/MS. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Klotho Regulates 14-3-3ζ Monomerization and Binding to the ASK1 Signaling Complex in Response to Oxidative Stress.

    Directory of Open Access Journals (Sweden)

    Reynolds K Brobey

    Full Text Available The reactive oxygen species (ROS-sensitive apoptosis signal-regulating kinase 1 (ASK1 signaling complex is a key regulator of p38 MAPK activity, a major modulator of stress-associated with aging disorders. We recently reported that the ratio of free ASK1 to the complex-bound ASK1 is significantly decreased in Klotho-responsive manner and that Klotho-deficient tissues have elevated levels of free ASK1 which coincides with increased oxidative stress. Here, we tested the hypothesis that: 1 covalent interactions exist among three identified proteins constituting the ASK1 signaling complex; 2 in normal unstressed cells the ASK1, 14-3-3ζ and thioredoxin (Trx proteins simultaneously engage in a tripartite complex formation; 3 Klotho's stabilizing effect on the complex relied solely on 14-3-3ζ expression and its apparent phosphorylation and dimerization changes. To verify the hypothesis, we performed 14-3-3ζ siRNA knock-down experiments in conjunction with cell-based assays to measure ASK1-client protein interactions in the presence and absence of Klotho, and with or without an oxidant such as rotenone. Our results show that Klotho activity induces posttranslational modifications in the complex targeting 14-3-3ζ monomer/dimer changes to effectively protect against ASK1 oxidation and dissociation. This is the first observation implicating all three proteins constituting the ASK1 signaling complex in close proximity.

  17. Klotho and S100A8/A9 as Discriminative Markers between Pre-Renal and Intrinsic Acute Kidney Injury.

    Directory of Open Access Journals (Sweden)

    Ae Jin Kim

    Full Text Available Early detection and accurate differentiation of the cause of AKI may improve the prognosis of the patient. However, to date, there are few reliable biomarkers that can discriminate between pre-renal and intrinsic AKI. In this study, we determined whether AKI is associated with altered serum and urinary levels of Klotho, S100A8/A9 (an endogenous ligand of toll-like receptor 4, and neutrophil gelatinase-associated lipocalin (NGAL, which may allow differentiation between pre-renal and intrinsic AKI. A volume-depleted pre-renal AKI model was induced in male Sprague Dawley rats fed a low-salt diet (0.03% without water 96 h before two intraperitoneal (IP injections of furosemide (20 mg/kg at a 24 h interval. In contrast, in the cisplatin-induced intrinsic AKI model, animals were given a single IP injection of cisplatin (5 mg/kg. All of the animals were euthanized 72 h after the first IP injection. Serum and urinary levels of Klotho, S100A8/A9, and NGAL were measured using an enzyme-linked immunosorbent assay. We also performed a proof-of-concept cross-sectional study to measure serum and urinary biomarkers in 61 hospitalized patients with established AKI. Compared to the intrinsic AKI group, the pre-renal AKI group showed a marked depression in urinary Klotho levels (13.21 ± 17.32 vs. 72.97 ± 17.96 pg/mL; P = 0.002. In addition, the intrinsic AKI group showed marked elevation of S100A8/A9 levels compared to the pre-renal AKI group (2629.97 ± 598.05 ng/mL vs. 685.09 ± 111.65 ng/mL; P = 0.002 in serum; 3361.11 ± 250.86 ng/mL vs. 741.72 ± 101.96 ng/mL; P = 0.003 in urine. There was no difference in serum and urinary NGAL levels between the pre-renal and intrinsic AKI groups. The proof-of-concept study with the hospitalized AKI patients also demonstrated decreased urinary Klotho in pre-renal AKI patients and increased urinary S100A8/A9 concentrations in intrinsic AKI patients. The attenuation of urinary Klotho and increase in urinary S100A8/A9 may

  18. Klotho-beta overexpression as a novel target for suppressing proliferation and fibroblast growth factor receptor-4 signaling in hepatocellular carcinoma

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    Poh Weijie

    2012-03-01

    Full Text Available Abstract Background We had previously demonstrated overexpression of fibroblast growth factor receptor-4 (FGFR4 in hepatocellular carcinoma (HCC. However, additional molecular mechanisms resulting in amplified FGFR4 signaling in HCC remain under-studied. Here, we studied the mechanistic role of its co-receptor klotho-beta (KLB in driving elevated FGFR4 activity in HCC progression. Results Quantitative real-time PCR analysis identified frequent elevation of KLB gene expression in HCC tumors relative to matched non-tumor tissue, with a more than two-fold increase correlating with development of multiple tumors in patients. KLB-silencing in Huh7 cells decreased cell proliferation and suppressed FGFR4 downstream signaling. While transient repression of KLB-FGFR4 signaling decreased protein expression of alpha-fetoprotein (AFP, a HCC diagnostic marker, prolonged inhibition enriched for resistant HCC cells exhibiting increased liver stemness. Conclusions Elevated KLB expression in HCC tissues provides further credence to the oncogenic role of increased FGFR4 signaling in HCC progression and represents a novel biomarker to identify additional patients amenable to anti-FGFR4 therapy. The restricted tissue expression profile of KLB, together with the anti-proliferative effect observed with KLB-silencing, also qualifies it as a specific and potent therapeutic target for HCC patients. The enrichment of a liver stem cell-like population in response to extended KLB-FGFR4 repression necessitates further investigation to target the development of drug resistance.

  19. ATP Induces IL-1β Secretion in Neisseria gonorrhoeae-Infected Human Macrophages by a Mechanism Not Related to the NLRP3/ASC/Caspase-1 Axis

    Directory of Open Access Journals (Sweden)

    Killen García

    2016-01-01

    Full Text Available Neisseria gonorrhoeae (Ngo has developed multiple immune evasion mechanisms involving the innate and adaptive immune responses. Recent findings have reported that Ngo reduces the IL-1β secretion of infected human monocyte-derived macrophages (MDM. Here, we investigate the role of adenosine triphosphate (ATP in production and release of IL-1β in Ngo-infected MDM. We found that the exposure of Ngo-infected MDM to ATP increases IL-1β levels about ten times compared with unexposed Ngo-infected MDM (P0.05 and caspase-1 (CASP1, P>0.05. In addition, ATP was not able to modify caspase-1 activity in Ngo-infected MDM but was able to increase pyroptosis (P>0.01. Notably ATP treatment defined an increase of positive staining for IL-1β with a distinctive intracellular pattern of distribution. Collectively, these data demonstrate that ATP induces IL-1β secretion by a mechanism not related to the NLRP3/ASC/caspase-1 axis and likely is acting at the level of vesicle trafficking or pore formation.

  20. ATP Induces IL-1β Secretion in Neisseria gonorrhoeae-Infected Human Macrophages by a Mechanism Not Related to the NLRP3/ASC/Caspase-1 Axis

    Science.gov (United States)

    García, Killen; Escobar, Gisselle; Mendoza, Pablo; Beltran, Caroll; Perez, Claudio; Vernal, Rolando; Acuña-Castillo, Claudio

    2016-01-01

    Neisseria gonorrhoeae (Ngo) has developed multiple immune evasion mechanisms involving the innate and adaptive immune responses. Recent findings have reported that Ngo reduces the IL-1β secretion of infected human monocyte-derived macrophages (MDM). Here, we investigate the role of adenosine triphosphate (ATP) in production and release of IL-1β in Ngo-infected MDM. We found that the exposure of Ngo-infected MDM to ATP increases IL-1β levels about ten times compared with unexposed Ngo-infected MDM (P 0.05) and caspase-1 (CASP1, P > 0.05). In addition, ATP was not able to modify caspase-1 activity in Ngo-infected MDM but was able to increase pyroptosis (P > 0.01). Notably ATP treatment defined an increase of positive staining for IL-1β with a distinctive intracellular pattern of distribution. Collectively, these data demonstrate that ATP induces IL-1β secretion by a mechanism not related to the NLRP3/ASC/caspase-1 axis and likely is acting at the level of vesicle trafficking or pore formation. PMID:27803513

  1. Metabolic effects of free fatty acids during endotoxaemia in a porcine model--free fatty acid inhibition of growth hormone secretion as a potential catabolic feedback mechanism.

    Science.gov (United States)

    Buhl, M; Gjedsted, J; Granfeldt, A; Larsen, P Ø; Schmitz, O; Tønnesen, E; Møller, N

    2010-05-01

    Critical illness and severe inflammation are catabolic states characterised by breakdown of tissue and protein stores, by increased levels of free fatty acids, and by insulin resistance. These metabolic features contribute to morbidity and mortality. Growth hormone and insulin are the two major anabolic hormones. The present study was designed to test whether increased levels of free fatty acids (i) inhibit growth hormone secretion and (ii) induce insulin resistance during acute endotoxin exposure in a porcine model of critical illness. We studied 20 pigs for 6 h during combined anaesthesia and endotoxin infusion and a hyperinsulinaemic glucose clamp to control glucose, insulin, and free fatty acid concentrations. Pigs were randomised to two different continuous infusion rates of Intralipid resulting in different, sustained, and elevated free fatty acid concentrations (1.63 mmol l(-1) vs. 0.58 mmol l(-1), p=0.0002). Concomitantly, we observed reduced growth hormone concentrations in the group with high free fatty acid concentrations (3.5 ng ml(-1) vs. 6.6 ng ml(-1), pfeedback mechanism whereby growth hormone induced-stimulation of free fatty acids release inhibit growth hormone secretion. This mechanism may further contribute to protein loss in critical illness. We found no evidence that the increment of plasma free fatty acids between groups contribute to insulin resistance in critical illness. Georg Thieme Verlag KG Stuttgart-New York.

  2. [Effect of continuous aspiration of subglottic secretions on the prevention of ventilator-associated pneumonia in mechanically ventilated patients: a prospective, randomized, controlled clinical trial].

    Science.gov (United States)

    Yang, Cong-shan; Qiu, Hai-bo; Zhu, Yan-ping; Huang, Ying-zi; Xu, Xiao-ting; Gao, Liang

    2008-08-01

    To evaluate the effect of continuous aspiration of subglottic secretions (CASS) on the prevention of ventilator-associated pneumonia (VAP) in mechanically ventilated patients. Patients ventilated mechanically at the ICU from October, 2004 to April, 2006 were randomly divided into 2 groups: one group received CASS and the other did not (NASS group). CASS was performed immediately after admission for patients in the CASS group. The diagnosis of VAP was made based on clinical presentations, and the evaluation of VAP was done using simplified version of the clinical pulmonary infection score (CPIS). The general status of the patients, days of ventilated treatment, the volume of daily aspirated subglottic secretions, the morbidity and timing of VAP, days of stay in ICU and mortality within 28 days of hospitalization were recorded. One hundred and one patients were included in the study. There were 48 patients in the CASS group who were treated with mechanical ventilation more than 48 hours, and 43 patients in the NASS group. There was no significant difference in the general status of the patients and days of ventilation between 2 groups with the averaged score of APACHE II being 20.8 +/- 6.1. The average of CPIS was of 5.6 +/- 1.0 when VAP was diagnosed. The mean volume of aspirated subglottic secretions within the first 24 hours in the CASS group (n = 48) was (27.2 +/- 21.2) ml. The morbidity of VAP in the CASS and the NASS groups was 25.0% and 46.5% respectively (P = 0.032), and the length of time before the onset of VAP in these 2 groups was (7.3 +/- 4.2) days and (5.1 +/- 3.0) days respectively (P = 0.100). There was a significant increase in the percentage of gram-positive cocci from the lower respiratory tracts in the NASS group compared with that in the CASS group (P = 0.004). In the CASS group, the volume of the first daily aspirated subglottic secretions in patients with VAP was significantly less than that in patients without VAP (P = 0.006). The morbidity of

  3. High Fat Diet Attenuates the Anticontractile Activity of Aortic PVAT via a Mechanism Involving AMPK and Reduced Adiponectin Secretion

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    Tarek A. M. Almabrouk

    2018-02-01

    Full Text Available Background and aim: Perivascular adipose tissue (PVAT positively regulates vascular function through production of factors such as adiponectin but this effect is attenuated in obesity. The enzyme AMP-activated protein kinase (AMPK is present in PVAT and is implicated in mediating the vascular effects of adiponectin. In this study, we investigated the effect of an obesogenic high fat diet (HFD on aortic PVAT and whether any changes involved AMPK.Methods: Wild type Sv129 (WT and AMPKα1 knockout (KO mice aged 8 weeks were fed normal diet (ND or HFD (42% kcal fat for 12 weeks. Adiponectin production by PVAT was assessed by ELISA and AMPK expression studied using immunoblotting. Macrophages in PVAT were identified using immunohistochemistry and markers of M1 and M2 macrophage subtypes evaluated using real time-qPCR. Vascular responses were measured in endothelium-denuded aortic rings with or without attached PVAT. Carotid wire injury was performed and PVAT inflammation studied 7 days later.Key results: Aortic PVAT from KO and WT mice was morphologically indistinct but KO PVAT had more infiltrating macrophages. HFD caused an increased infiltration of macrophages in WT mice with increased expression of the M1 macrophage markers Nos2 and Il1b and the M2 marker Chil3. In WT mice, HFD reduced the anticontractile effect of PVAT as well as reducing adiponectin secretion and AMPK phosphorylation. PVAT from KO mice on ND had significantly reduced adiponectin secretion and no anticontractile effect and feeding HFD did not alter this. Wire injury induced macrophage infiltration of PVAT but did not cause further infiltration in KO mice.Conclusions: High-fat diet causes an inflammatory infiltrate, reduced AMPK phosphorylation and attenuates the anticontractile effect of murine aortic PVAT. Mice lacking AMPKα1 phenocopy many of the changes in wild-type aortic PVAT after HFD, suggesting that AMPK may protect the vessel against deleterious changes in response to

  4. Secret Places.

    Science.gov (United States)

    Ridolfi, Kerry

    1997-01-01

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

  5. The FGF-23/Klotho axis and its relationship with phosphorus, calcium, vitamin D, PTH, aldosterone, severity of disease, and outcome in hospitalised foals.

    Science.gov (United States)

    Kamr, A M; Dembek, K A; Hildreth, B E; Morresey, P R; Rathgeber, R A; Burns, T A; Zaghawa, A A; Toribio, R E

    2018-04-16

    Fibroblast growth factor-23 (FGF-23) and klotho are key regulators of vitamin D and parathyroid hormone (PTH) synthesis as well as phosphorus and calcium homeostasis; however, information on the FGF-23/klotho axis in healthy and hospitalised foals is lacking. The aims of this study were to measure serum FGF-23 and klotho concentrations and determine their association with serum phosphorus, total calcium (TCa), vitamin D metabolite [25(OH)D, 1,25(OH) 2 D], PTH, and aldosterone concentrations, disease severity, and mortality in hospitalised foals. Prospective, multicentre, cross-sectional study. A total of 91 foals ≤72 hours old were classified as hospitalised (n = 81; 58 septic; 23 sick non-septic [SNS]) and healthy (n = 10). Blood samples were collected on admission. Hormone concentrations were determined by immunoassays. Serum FGF-23, PTH, phosphorus, and aldosterone concentrations were higher while klotho, 25(OH)D, 1,25(OH) 2 D, and TCa concentrations were lower in septic and SNS compared to healthy foals (PPTH but not with TCa and vitamin D metabolite concentrations. Hospitalised foals with the highest FGF-23 and lowest klotho concentrations were more likely to die (odds ratio (OR): 3.3; 95% confidence interval (CI): 1.1-10.3 and OR: 3.1; CI: 1.1-8.0, respectively). Blood gas, ionised calcium, blood culture information not being available for many foals, and use of the sepsis score to classify hospitalised foals. Imbalances in the FGF-23/klotho axis may contribute to mineral dyshomeostasis and disease progression in critically ill foals. Elevated FGF-23 and reduced klotho, together with high phosphorus and PTH concentrations suggests FGF-23 resistance. FGF-23 and klotho are good markers of disease severity and likelihood of mortality in hospitalised foals. Aldosterone may influence phosphorus and PTH dynamics in hospitalised foals. Routine measurement of phosphorus concentrations in sick foals is recommended. This article is protected by copyright. All rights

  6. Contribution of the organic anion transporter OAT2 to the renal active tubular secretion of creatinine and mechanism for serum creatinine elevations caused by cobicistat

    Science.gov (United States)

    Lepist, Eve-Irene; Zhang, Xuexiang; Hao, Jia; Huang, Jane; Kosaka, Alan; Birkus, Gabriel; Murray, Bernard P; Bannister, Roy; Cihlar, Tomas; Huang, Yong; Ray, Adrian S

    2014-01-01

    Many xenobiotics including the pharmacoenhancer cobicistat increase serum creatinine by inhibiting its renal active tubular secretion without affecting the glomerular filtration rate. This study aimed to define the transporters involved in creatinine secretion, applying that knowledge to establish the mechanism for xenobiotic-induced effects. The basolateral uptake transporters organic anion transporter OAT2 and organic cation transporters OCT2 and OCT3 were found to transport creatinine. At physiologic creatinine concentrations, the specific activity of OAT2 transport was over twofold higher than OCT2 or OCT3, establishing OAT2 as a likely relevant creatinine transporter and further challenging the traditional view that creatinine is solely transported by a cationic pathway. The apical multidrug and toxin extrusion transporters MATE1 and MATE2-K demonstrated low-affinity and high-capacity transport. All drugs known to affect creatinine inhibited OCT2 and MATE1. Similar to cimetidine and ritonavir, cobicistat had the greatest effect on MATE1 with a 50% inhibition constant of 0.99 μM for creatinine transport. Trimethoprim potently inhibited MATE2-K, whereas dolutegravir preferentially inhibited OCT2. Cimetidine was unique, inhibiting all transporters that interact with creatinine. Thus, the clinical observation of elevated serum creatinine in patients taking cobicistat is likely a result of OCT2 transport, facilitating intracellular accumulation, and MATE1 inhibition. PMID:24646860

  7. Interfacial binding of bee venom secreted phospholipase A2 to membranes occurs predominantly by a nonelectrostatic mechanism.

    Science.gov (United States)

    Bollinger, James G; Diraviyam, Karthikeyan; Ghomashchi, Farideh; Murray, Diana; Gelb, Michael H

    2004-10-26

    The secreted phospholipase A(2) from bee venom (bvPLA(2)) contains a membrane binding surface composed mainly of hydrophobic residues and two basic residues that come in close contact with the membrane. Previous studies have shown that the mutant in which these two basic residues (K14 and R23) as well as three other nearby basic residues were collectively changed to glutamate (charge reversal), like wild-type enzyme, binds with high affinity to anionic phospholipid vesicles. In the present study, we have measured the equilibrium constants for the interaction of wild-type bvPLA(2), the charge-reversal mutant (bvPLA(2)-E5), and the mutant in which the five basic residues were changed to neutral glutamine (bvPLA(2)-Q5) with phosphatidylcholine (PC) vesicles containing various amounts of the anionic phosphatidylserine (PS). Remarkably, bvPLA(2)-E5 with an anionic membrane binding surface binds more tightly to vesicles as the mole percent of PS is increased. Computational studies predict that this is due to a significant upward shift in the pK(a) of E14 (and to some extent E23) when the enzyme binds to PC/PS vesicles such that the carboxylate of the glutamate side chain near the membrane surface undergoes protonation. The experimental pH dependence of vesicle binding supports this prediction. bvPLA(2)-E5 binds more weakly to PS/PC vesicles than does wild-type enzyme due to electrostatic protein-vesicle repulsion coupled with the similar energetics of desolvation of basic residues and glutamates that accompanies enzyme-vesicle contact. Studies with bvPLA(2)-Q5 show that only a small fraction of the total bvPLA(2) interfacial binding energy ( approximately 10%) is due to electrostatics.

  8. Salmonella-secreted Virulence Factors

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-05-01

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

  9. Heterogeneity of type III secretion system (T3SS)-1-independent entry mechanisms used by Salmonella Enteritidis to invade different cell types.

    Science.gov (United States)

    Rosselin, Manon; Abed, Nadia; Virlogeux-Payant, Isabelle; Bottreau, Elisabeth; Sizaret, Pierre-Yves; Velge, Philippe; Wiedemann, Agnès

    2011-03-01

    Salmonella causes a wide range of diseases from acute gastroenteritis to systemic typhoid fever, depending on the host. To invade non-phagocytic cells, Salmonella has developed different mechanisms. The main invasion system requires a type III secretion system (T3SS) known as T3SS-1, which promotes a Trigger entry mechanism. However, other invasion factors have recently been described in Salmonella, including Rck and PagN, which were not expressed under our bacterial culture conditions. Based on these observations, we used adhesion and invasion assays to analyse the respective roles of Salmonella Enteritidis T3SS-1-dependent and -independent invasion processes at different times of infection. Diverse cell lines and cell types were tested, including endothelial, epithelial and fibroblast cells. We demonstrated that cell susceptibility to the T3SS-1-independent entry differs by a factor of nine between the most and the least permissive cell lines tested. In addition, using scanning electron and confocal microscopy, we showed that T3SS-1-independent entry into cells was characterized by a Trigger-like alteration, as for the T3SS-1-dependent entry, and also by Zipper-like cellular alteration. Our results demonstrate for what is believed to be the first time that Salmonella can induce Trigger-like entry independently of T3SS-1 and can induce Zipper-like entry independently of Rck. Overall, these data open new avenues for discovering new invasion mechanisms in Salmonella.

  10. Klotho G-395A gene polymorphism: impact on progression of end-stage renal disease and development of cardiovascular complications in children on dialysis.

    Science.gov (United States)

    Elghoroury, Eman A; Fadel, Fatina I; Elshamaa, Manal F; Kandil, Dina; Salah, Doaa M; El-Sonbaty, Marwa M; Farouk, Hebatallah; Raafat, Mona; Nasr, Soha

    2018-01-08

    Klotho G-395-A gene polymorphism may impact children with end-stage renal disease (ESRD). We investigated the relevance of Klotho G-395-A on ESRD development and progression, and its relationship with evolution of cardiovascular complications in pediatric dialysis patients. Fifty-five children with chronic kidney disease (CKD) and seventy healthy children were genotyped for Klotho G-395A. Incidence of GA/AA genotypes and A allele were higher in ESRD patients compared with controls (54.5 vs. 7.1%, P children with GA/AA genotypes were 15.6 times more likely to develop ESRD than with GG genotype (95% CI 5.4-44.7, P disease (CVD), as carriers have 161 times higher risk of cardiovascular complications than non-carriers (95% CI 21-1233, P children with LVH, whereas G allele frequency was significantly higher among ESRD children without LVH. The A allele of the G-395A Klotho gene polymorphism shows a significantly higher frequency among children with CKD and those with CVD and LVH. This mutant allele could be used as a risk marker for the development of ESRD as well as a predictor of CVD in these children.

  11. Google Secrets

    CERN Document Server

    Davis, Yvette

    2011-01-01

    Become a Google guru with these effective tips, tricks, and techniques Sure, you use Google. But do you really use Google-and everything it has to offer-in the most effective way possible? Wish you could just sit down with a Google expert who would show you how to take your Google savviness to the next level? With Google Secrets, you can! Tech expert Jerri Ledford reveals the ins, outs, and little-known facts about Google to show you how to sharpen your skills so you can get more done, more efficiently. You may already be familiar with Google's most popular applications, but this indispensable

  12. Klotho Gene and Selective Serotonin Reuptake Inhibitors: Response to Treatment in Late-Life Major Depressive Disorder.

    Science.gov (United States)

    Paroni, Giulia; Seripa, Davide; Fontana, Andrea; D'Onofrio, Grazia; Gravina, Carolina; Urbano, Maria; Addante, Filomena; Lozupone, Madia; Copetti, Massimiliano; Pilotto, Alberto; Greco, Antonio; Panza, Francesco

    2017-03-01

    Klotho protein, encoded by the Klotho gene (KL) at locus 13q12, is an antiaging hormone-like protein playing a pivotal role in cell metabolism homeostasis and associated to longevity and age-related diseases. In particular, altered cell metabolism in central nervous system may influence the behavior of serotoninergic neurons. The role of KL in the response to treatment with selective serotonin reuptake inhibitors (SSRIs) in late-life depressive syndromes and late-life major depressive disorder (MDD) is unclear. We genotyped three single-nucleotide polymorphisms (SNPs) of KL in 329 older patients with diagnosis of late-life MDD, treated with SSRIs and evaluated with the Hamilton Rating Scale for Depression 21-items (HRSD-21) at baseline and after 6 months. A reduction ≥50 and depressive symptoms after treatment in patients carrying at least one minor allele at rs1207568 and a worse response in patients homozygous for the minor allele at rs9536314. Our results were the first that suggested a possible role of KL in the complex pathway of SSRI response in late-life MDD.

  13. The Structure of a Type 3 Secretion System (T3SS) Ruler Protein Suggests a Molecular Mechanism for Needle Length Sensing*

    Science.gov (United States)

    Bergeron, Julien R. C.; Fernández, Lucia; Wasney, Gregory A.; Vuckovic, Marija; Reffuveille, Fany; Hancock, Robert E. W.; Strynadka, Natalie C. J.

    2016-01-01

    The type 3 secretion system (T3SS) and the bacterial flagellum are related pathogenicity-associated appendages found at the surface of many disease-causing bacteria. These appendages consist of long tubular structures that protrude away from the bacterial surface to interact with the host cell and/or promote motility. A proposed “ruler” protein tightly regulates the length of both the T3SS and the flagellum, but the molecular basis for this length control has remained poorly characterized and controversial. Using the Pseudomonas aeruginosa T3SS as a model system, we report the first structure of a T3SS ruler protein, revealing a “ball-and-chain” architecture, with a globular C-terminal domain (the ball) preceded by a long intrinsically disordered N-terminal polypeptide chain. The dimensions and stability of the globular domain do not support its potential passage through the inner lumen of the T3SS needle. We further demonstrate that a conserved motif at the N terminus of the ruler protein interacts with the T3SS autoprotease in the cytosolic side. Collectively, these data suggest a potential mechanism for needle length sensing by ruler proteins, whereby upon T3SS needle assembly, the ruler protein's N-terminal end is anchored on the cytosolic side, with the globular domain located on the extracellular end of the growing needle. Sequence analysis of T3SS and flagellar ruler proteins shows that this mechanism is probably conserved across systems. PMID:26589798

  14. Melatonin Attenuates Memory Impairment Induced by Klotho Gene Deficiency Via Interactive Signaling Between MT2 Receptor, ERK, and Nrf2-Related Antioxidant Potential

    Science.gov (United States)

    Shin, Eun-Joo; Chung, Yoon Hee; Le, Hoang-Lan Thi; Jeong, Ji Hoon; Dang, Duy-Khanh; Nam, Yunsung; Wie, Myung Bok; Nah, Seung-Yeol; Nabeshima, Yo-Ichi; Nabeshima, Toshitaka; Kim, Hyoung-Chun

    2015-01-01

    Background: We demonstrated that oxidative stress plays a crucial role in cognitive impairment in klotho mutant mice, a genetic model of aging. Since down-regulation of melatonin due to aging is well documented, we used this genetic model to determine whether the antioxidant property of melatonin affects memory impairment. Methods: First, we examined the effects of melatonin on hippocampal oxidative parameters and the glutathione/oxidized glutathione (GSH/GSSG) ratio and memory dysfunction of klotho mutant mice. Second, we investigated whether a specific melatonin receptor is involved in the melatonin-mediated pharmacological response by application with melatonin receptor antagonists. Third, we examined phospho-extracellular-signal-regulated kinase (ERK) expression, nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear translocation, Nrf2 DNA binding activity, and glutamate-cysteine ligase (GCL) mRNA expression. Finally, we examined effects of the ERK inhibitor SL327 in response to antioxidant efficacy and memory enhancement mediated by melatonin. Results: Treatment with melatonin resulted in significant attenuations of oxidative damage, a decrease in the GSH/GSSG ratio, and a significant amelioration of memory impairment in this aging model. These effects of melatonin were significantly counteracted by the selective MT2 receptor antagonist 4-P-PDOT. Importantly, 4-P-PDOT or SL327 also counteracted melatonin-mediated attenuation in response to the decreases in phospho-ERK expression, Nrf2 nuclear translocation, Nrf2 DNA-binding activity, and GCL mRNA expression in the hippocampi of klotho mutant mice. SL327 also counteracted the up-regulation of the GSH/GSSG ratio and the memory enhancement mediated by melatonin in klotho mutant mice. Conclusions: Melatonin attenuates oxidative stress and the associated memory impairment induced by klotho deficiency via signaling interaction between the MT2 receptor and ERK- and Nrf2-related antioxidant potential. PMID

  15. Klotho gene delivery ameliorates renal hypertrophy and fibrosis in streptozotocin-induced diabetic rats by suppressing the Rho-associated coiled-coil kinase signaling pathway.

    Science.gov (United States)

    Deng, Minghong; Luo, Yumei; Li, Yunkui; Yang, Qiuchen; Deng, Xiaoqin; Wu, Ping; Ma, Houxun

    2015-07-01

    The present study aimed to investigate whether klotho gene delivery attenuated renal hypertrophy and fibrosis in streptozotocin-induced diabetic rats. A recombinant adeno-associated virus (rAAV) carrying mouse klotho full-length cDNA (rAAV.mKL), was constructed for in vivo investigation of klotho expression. Diabetes was induced in rats by a single tail vein injection of 60 mg/kg streptozotocin. Subsequently, the diabetic rats received an intravenous injection of rAAV.mKL, rAAV.green fluorescent protein (GFP) or phosphate-buffered saline (PBS). The Sprague-Dawley rat group received PBS and served as the control group. After 12 weeks, all the rats were sacrificed and ELISA, immunohistochemical and histological analyses, fluorescence microscopy, semi-quantitative reverse transcription-polymerase chain reaction and western blottin were performed. A single dose of rAAV.mKL was found to prevent the progression of renal hypertrophy and fibrosis for at least 12 weeks (duration of study). Klotho expression was suppressed in the diabetic rats, but was increased by rAAV.mKL delivery. rAAV.mKL significantly suppressed diabetes-induced renal hypertrophy and histopathological changes, reduced renal collagen fiber generation and decreased kidney hypertrophy index. In addition, rAAV.mKL decreased the protein expression levels of fibronectin and vimentin, while it downregulated the mRNA expression and activity of Rho-associated coiled-coil kinase (ROCK)I in the kidneys of the diabetic rats. These results indicated that klotho gene delivery ameliorated renal hypertrophy and fibrosis in diabetic rats, possibly by suppressing the ROCK signaling pathway. This may offer a novel approach for the long-term control and renoprotection of diabetes.

  16. Entamoeba histolytica-secreted cysteine proteases induce IL-8 production in human mast cells via a PAR2-independent mechanism

    Directory of Open Access Journals (Sweden)

    Lee Young Ah

    2014-01-01

    Full Text Available Entamoeba histolytica is an extracellular tissue parasite causing colitis and occasional liver abscess in humans. E. histolytica-derived secretory products (SPs contain large amounts of cysteine proteases (CPs, one of the important amoebic virulence factors. Although tissue-residing mast cells play an important role in the mucosal inflammatory response to this pathogen, it is not known whether the SPs induce mast cell activation. In this study, when human mast cells (HMC-1 cells were stimulated with SPs collected from pathogenic wild-type amoebae, interleukin IL-8 mRNA expression and production were significantly increased compared with cells incubated with medium alone. Inhibition of CP activity in the SPs with heat or the CP inhibitor E64 resulted in significant reduction of IL-8 production. Moreover, SPs obtained from inhibitors of cysteine protease (ICP-overexpressing amoebae with low CP activity showed weaker stimulatory effects on IL-8 production than the wild-type control. Preincubation of HMC-1 cells with antibodies to human protease-activated receptor 2 (PAR2 did not affect the SP-induced IL-8 production. These results suggest that cysteine proteases in E. histolytica-derived secretory products stimulate mast cells to produce IL-8 via a PAR2-independent mechanism, which contributes to IL-8-mediated tissue inflammatory responses during the early phase of human amoebiasis.

  17. Study on the mechanism of allelopathic influence on cyanobacteria and chlorophytes by submerged macrophyte (Myriophyllum spicatum) and its secretion

    International Nuclear Information System (INIS)

    Zhu Junying; Liu Biyun; Wang Jing; Gao Yunni; Wu Zhenbin

    2010-01-01

    For revealing the mechanism of allelopathic influence on phytoplankton by aquatic macrophytes, the growth and photosynthetic activities of cyanobacteria Microcystis aeruginosa and the chlorophyte Selenastrum capricornutum were investigated when they coexisted with submerged macrophyte Myriophyllum spicatum and were exposed to allelopathic polyphenols: pyrogallic acid (PA), gallic acid (GA), ellagic acid (EA) and (+)-catechin (CA). According to the results of coexistence assays, the non-photochemical quenching (NPQ) and effective quantum efficiency (YII) of M. aeruginosa were affected earlier and more rapidly than the cell density. However, the influence of M. spicatum on S. capricornutum was not found. When the Toxicity Index (TI) was applied to evaluate the combined effects of binary and multiple mixtures of polyphenols, it was found that the four tested polyphenols with the proportion identified in the M. spicatum-cultured solution were observed to present synergistic effect (0.36-0.49) according to the cell density, NPQ and YII of M. aeruginosa. With the combined effects of polyphenols on S. capricornutum, only additive action (0.52-1.62) was found. On the other hand, PA (2.97 mg L -1 ), GA (2.65 mg L -1 ) caused significant reductions of photosystem II (PSII) and whole electron transport chain activities of M. aeruginosa by 71.43 and 18.37%, 70.95 and 40.77% (P < 0.05), respectively, after 24-h exposure, but no inhibition effect was found in S. capricornutum. The dark respiration and photosystem I (PSI) activities of M. aeruginosa were significantly increased by exposure to PA and GA (P < 0.05). Nevertheless, EA and CA had no influence on the electron transport activities of the tested organisms. These results indicate that the reduction in photosynthetic activity of M. aeruginosa and the synergistic effect of allelochemicals may be two important causes for the inhibition of undesired phytoplankton by submersed macrophytes in natural aquatic ecosystems, and

  18. Study on the mechanism of allelopathic influence on cyanobacteria and chlorophytes by submerged macrophyte (Myriophyllum spicatum) and its secretion

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Junying [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Liu Biyun [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072 (China); Wang Jing; Gao Yunni [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Wu Zhenbin, E-mail: wuzb@ihb.ac.cn [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072 (China)

    2010-06-10

    For revealing the mechanism of allelopathic influence on phytoplankton by aquatic macrophytes, the growth and photosynthetic activities of cyanobacteria Microcystis aeruginosa and the chlorophyte Selenastrum capricornutum were investigated when they coexisted with submerged macrophyte Myriophyllum spicatum and were exposed to allelopathic polyphenols: pyrogallic acid (PA), gallic acid (GA), ellagic acid (EA) and (+)-catechin (CA). According to the results of coexistence assays, the non-photochemical quenching (NPQ) and effective quantum efficiency (YII) of M. aeruginosa were affected earlier and more rapidly than the cell density. However, the influence of M. spicatum on S. capricornutum was not found. When the Toxicity Index (TI) was applied to evaluate the combined effects of binary and multiple mixtures of polyphenols, it was found that the four tested polyphenols with the proportion identified in the M. spicatum-cultured solution were observed to present synergistic effect (0.36-0.49) according to the cell density, NPQ and YII of M. aeruginosa. With the combined effects of polyphenols on S. capricornutum, only additive action (0.52-1.62) was found. On the other hand, PA (2.97 mg L{sup -1}), GA (2.65 mg L{sup -1}) caused significant reductions of photosystem II (PSII) and whole electron transport chain activities of M. aeruginosa by 71.43 and 18.37%, 70.95 and 40.77% (P < 0.05), respectively, after 24-h exposure, but no inhibition effect was found in S. capricornutum. The dark respiration and photosystem I (PSI) activities of M. aeruginosa were significantly increased by exposure to PA and GA (P < 0.05). Nevertheless, EA and CA had no influence on the electron transport activities of the tested organisms. These results indicate that the reduction in photosynthetic activity of M. aeruginosa and the synergistic effect of allelochemicals may be two important causes for the inhibition of undesired phytoplankton by submersed macrophytes in natural aquatic ecosystems

  19. Increased interleukin-10 in the the endocervical secretions of women with non-ulcerative sexually transmitted diseases: a mechanism for enhanced HIV-1 transmission?

    Science.gov (United States)

    Cohen, C R; Plummer, F A; Mugo, N; Maclean, I; Shen, C; Bukusi, E A; Irungu, E; Sinei, S; Bwayo, J; Brunham, R C

    1999-02-25

    Although non-ulcerative sexually transmitted diseases (STD) and bacterial vaginosis are implicated as cofactors in heterosexual HIV-1 transmission, the mechanisms have not been defined. Recent in vitro data suggest that interleukin (IL)-10 may increase susceptibility of macrophages to HIV-1 infection. Therefore, we performed this study to assess whether non-ulcerative STD are associated with detection of IL-10 in the female genital tract. Women with clinical pelvic inflammatory disease with or without cervicovaginal discharge were recruited from an STD clinic in Nairobi, Kenya. Endocervical and endometrial specimens were obtained for Neisseria gonorrhoeae and Chlamydia trachomatis DNA detection, Trichonomas vaginalis culture, and CD4 and CD8 T-cell enumeration. Bacterial vaginosis was diagnosed by Gram stain. IL-10 was detected in endocervical specimens using enzyme-linked immunosorbent assay. Blood was obtained for HIV-1 serology. One hundred and seventy-two women were studied. N. gonorrhoeae, C. trachomatis, bacterial vaginosis, and T. vaginalis were detected in 38 (21%), 17 (9%), 71 (43%), and 22 (12%) women, respectively. Cervical IL-10 was detected more often in women with N. gonorrhoeae [adjusted odds ratio (AOR), 3.4; 95% confidence interval (CI), 1.4-8.4], C. trachomatis (AOR, 4.4; 95% CI, 1.2-15.6), and bacterial vaginosis (AOR, 3.1; 95% CI, 1.4-6.9) than in women without these infections. The association of non-ulcerative STD and bacterial vaginosis with increased frequency of IL-10 detection in endocervical secretions suggests a potential mechanism through which these infections may alter susceptibility to HIV-1 infection in women.

  20. The Structure of a Type 3 Secretion System (T3SS) Ruler Protein Suggests a Molecular Mechanism for Needle Length Sensing.

    Science.gov (United States)

    Bergeron, Julien R C; Fernández, Lucia; Wasney, Gregory A; Vuckovic, Marija; Reffuveille, Fany; Hancock, Robert E W; Strynadka, Natalie C J

    2016-01-22

    The type 3 secretion system (T3SS) and the bacterial flagellum are related pathogenicity-associated appendages found at the surface of many disease-causing bacteria. These appendages consist of long tubular structures that protrude away from the bacterial surface to interact with the host cell and/or promote motility. A proposed "ruler" protein tightly regulates the length of both the T3SS and the flagellum, but the molecular basis for this length control has remained poorly characterized and controversial. Using the Pseudomonas aeruginosa T3SS as a model system, we report the first structure of a T3SS ruler protein, revealing a "ball-and-chain" architecture, with a globular C-terminal domain (the ball) preceded by a long intrinsically disordered N-terminal polypeptide chain. The dimensions and stability of the globular domain do not support its potential passage through the inner lumen of the T3SS needle. We further demonstrate that a conserved motif at the N terminus of the ruler protein interacts with the T3SS autoprotease in the cytosolic side. Collectively, these data suggest a potential mechanism for needle length sensing by ruler proteins, whereby upon T3SS needle assembly, the ruler protein's N-terminal end is anchored on the cytosolic side, with the globular domain located on the extracellular end of the growing needle. Sequence analysis of T3SS and flagellar ruler proteins shows that this mechanism is probably conserved across systems. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  1. Enfermedad óseo mineral relacionada con la enfermedad renal crónica: Klotho y FGF23; implicaciones cardiovasculares

    Directory of Open Access Journals (Sweden)

    Laura Salanova Villanueva

    2016-07-01

    Full Text Available Una de las principales causas de morbimortalidad en el paciente con enfermedad renal crónica es la cardiovascular. La inflamación y las alteraciones en el metabolismo óseo mineral son una condición patológica que conlleva aumento del riesgo cardiovascular en la enfermedad renal crónica. Los parámetros bioquímicos clásicos del metabolismo óseo mineral como fósforo, calcio, vitamina D y PTH tienen una implicación muy conocida en el riesgo cardiovascular. Los nuevos marcadores, FGF23 y klotho, también podrían estar implicados en la enfermedad cardiovascular.

  2. Association Study of Klotho Gene Polymorphism With Calcium Oxalate Stones in The Uyghur Population of Xinjiang, China.

    Science.gov (United States)

    Ali, Abdusamat; Tursun, Halmurat; Talat, Alim; Abla, Akpar; Muhtar, Erpan; Zhang, Tao; Mahmut, Murat

    2017-01-18

    The aim of the present study was to investigate the correlation between Klotho gene polymorphisms andcalcium oxalate stones in Xinjiang Uyghur people. We compared 128 patients with calcium oxalate stones (case group) and 94 healthypeople (control group), detected the genotype and allele distributions of single-nucleotide polymorphisms (SNPs)of the Klotho gene (rs3752472, rs650439, and rs1207568) by reverse transcription polymerase chain reaction. The distributions of the genotype and allele frequencies of the SNPs were consistent with the Hardy-Weinberg equilibrium in the two groups. There were statistically significant differences between the genotype andallele distributions of rs3752472 between the case and control groups; the allele frequencies in the case/controlgroups were C = 240 (93.7%)/151 (80.3%) and T = 16 (6.3%)/37 (19.7%). There was no statistically significantdifference in the genotype distribution of rs650439 between the case and control groups, but there was a differencein the allele distribution; the allele frequencies in the case/control groups were A = 202 (78.9%)/143 (57.2%) andT = 54 (21.1%)/107 (42.8%). There were no statistically significant differences in genotype and allele distributionsbetween the case and control groups of rs1207568; the allele frequencies in the case/control groups were C = 194(71.3%)/145 (77.1%) and T = 78 (28.7%)/43 (22.9%). In rs3752472, the risk for patients with the C and A allelesincreased by 3.675 and 2.799 times, respectively. The rs3752472 and rs650439 SNPs are related to the risk of calcium oxalate stones in Xinjiang Uyghurpeople, and might be one of the risk factors.

  3. Association between circulating fibroblast growth factor 23, α-Klotho, and the left ventricular ejection fraction and left ventricular mass in cardiology inpatients.

    Directory of Open Access Journals (Sweden)

    Kensaku Shibata

    Full Text Available BACKGROUND: Fibroblast growth factor 23 (FGF23, with its co-receptor Klotho, plays a crucial role in phosphate metabolism. Several recent studies suggested that circulating FGF23 and α-Klotho concentrations might be related to cardiovascular abnormalities in patients with advanced renal failure. PURPOSE: Using data from 100 cardiology inpatients who were not undergoing chronic hemodialysis, the association of circulating levels of FGF23, α-Klotho, and other calcium-phosphate metabolism-related parameters with the left ventricular ejection fraction (LVEF and left ventricular mass (LVM was analyzed. METHODS AND RESULTS: LVEF was measured using the modified Simpson method for apical 4-chamber LV images and the LVM index (LVMI was calculated by dividing the LVM by body surface area. Univariate analysis showed that log transformed FGF23, but not that of α-Klotho, was significantly associated with LVEF and LVMI with a standardized beta of -0.35 (P<0.001 and 0.26 (P<0.05, respectively. After adjusting for age, sex, estimated glomerular filtration rate, and serum concentrations of intact parathyroid hormone, and 25-hydroxyvitamin D as covariates into the statistical model, log-transformed FGF23 was found to be a statistically positive predictor for decreased left ventricular function and left ventricular hypertrophy. CONCLUSIONS: In cardiology department inpatients, circulating FGF23 concentrations were found to be associated with the left ventricular mass and LVEF independent of renal function and other calcium-phosphate metabolism-related parameters. Whether modulation of circulating FGF23 levels would improve cardiac outcome in such a high risk population awaits further investigation.

  4. Analysis of α-Klotho, Fibroblast Growth Factor-, Vitamin-D and Calcium-Sensing Receptor in 70 Patients with Secondary Hyperparathyroidism

    Directory of Open Access Journals (Sweden)

    Joerg Latus

    2013-03-01

    Full Text Available Background/Aims: Secondary hyperparathyroidism (sHPT is known as a very common complication in patients with chronic kidney disease, and G-protein-coupled calcium-sensing receptor (CaSR, Vitamin D receptor (VDR and Fibroblast growth factor receptor (FGFR/Klotho complexes seem to be involved in its development. Methods: Hyperplastic parathyroid glands from 70 sHPT patients and normal parathyroid tissue from 7 patients were obtained during parathyroidectomy. Conventional morphological and immunohistochemical analysis of parathyroid glands was performed after dividing each slide in a 3x3 array. Results: The presence of lipocytes in the normal parathyroid gland and tissue architecture (nodal in patients with sHPT allows for discrimination between normal parathyroid glands and parathyroid glands of patients with sHPT. Protein expression of Klotho, FGFR, CaSR and VDR was higher in the normal parathyroid glands compared to the sHPT group (p0.05. Conclusions: CaSR, VDR and an impaired Klotho-FGFR-axis seem to be the major players in the development of sHPT. Whether the detected correlation between FGFR and VDR and the shift to a more mixed nuclear/cytoplasmic staining of VDR will yield new insights into the pathogenesis of the disease has to be evaluated in further studies.

  5. Human Umbilical Cord-Derived Mesenchymal Stem Cells Improve Learning and Memory Function in Hypoxic-Ischemic Brain-Damaged Rats via an IL-8-Mediated Secretion Mechanism Rather than Differentiation Pattern Induction.

    Science.gov (United States)

    Zhou, Xiaoqin; Gu, Jialu; Gu, Yan; He, Mulan; Bi, Yang; Chen, Jie; Li, Tingyu

    2015-01-01

    MSCs are a promising therapeutic resource. Paracrine effects and the induction of differentiation patterns are thought to represent the two primary mechanisms underlying the therapeutic effects of mesenchymal stem cell (MSC) transplantation in vivo. However, it is unclear which mechanism is involved in the therapeutic effects of human umbilical cord-derived MSC (hUC-MSC) transplantation. Based on flow cytometry analysis, hUC-MSCs exhibited the morphological characteristics and surface markers of MSCs. Following directed neural induction, these cells displayed a neuron-like morphology and expressed high levels of neural markers. All types of hUC-MSCs, including differentiated and redifferentiated cells, promoted learning and memory function recovery in hypoxic-ischemic brain damaged (HIBD) rats. The hUC-MSCs secreted IL-8, which enhanced angiogenesis in the hippocampus via the JNK pathway. However, the differentiated and redifferentiated cells did not exert significantly greater therapeutic effects than the undifferentiated hUC-MSCs. hUC-MSCs display the biological properties and neural differentiation potential of MSCs and provide therapeutic advantages by secreting IL-8, which participates in angiogenesis in the rat HIBD model. These data suggest that hUC-MSC transplantation improves the recovery of neuronal function via an IL-8-mediated secretion mechanism, whereas differentiation pattern induction was limited. © 2015 S. Karger AG, Basel.

  6. Glucagon-like peptide-1 secretion is influenced by perfusate glucose concentration and by a feedback mechanism involving somatostatin in isolated perfused porcine ileum

    DEFF Research Database (Denmark)

    Hansen, Lene; Hartmann, Bolette; Mineo, Hitoshi

    2004-01-01

    isolated perfused porcine ileum (n=17). Effluents were measured for GLP-1 and SS. Perfusion pressure and motility were recorded. Investigated parameters included spontaneous fluctuations, changes in perfusate glucose concentrations (3.5, 5, 11 mM) and addition of insulin (1 nM). We also investigated...... the effect of proglucagon products, glucagon (10 nM), GLP-1 and GLP-2 (0.1, 1, and 10 nM) on GLP-1 and SS secretion, as well as on glucagon-like peptide-2 (GLP-2), peptide YY (PYY) and GIP secretion, all possible product of L-cells or neighbour cells. Perfusate glucose concentration dose...

  7. Metformin inhibits 17β-estradiol-induced epithelial-to-mesenchymal transition via βKlotho-related ERK1/2 signaling and AMPKα signaling in endometrial adenocarcinoma cells.

    Science.gov (United States)

    Liu, Zhao; Qi, Shasha; Zhao, Xingbo; Li, Mingjiang; Ding, Sentai; Lu, Jiaju; Zhang, Hui

    2016-04-19

    The potential role of metformin in treating endometrial cancer remains to be explored. The current study investigated the role of metformin in 17β-estradiol-induced epithelial-mesenchymal transition (EMT) in endometrial adenocarcinoma cells. We found that 17β-estradiol promoted proliferation and migration, attenuated apoptosis in both estrogen receptor (ER) positive and ER negative endometrial adenocarcinoma cells (Ishikawa and KLE cells, respectively). Metformin abolished 17β-estradiol-induced cell proliferation and reversed 17β-estradiol-induced EMT in Ishikawa cells. In addition, metformin increased the expression of βKlotho, a fibroblast growth factors (FGFs) coreceptor, and decreased ERK1/2 phosphorylation in both Ishikawa and KLE cells. Decreased expression of βKlotho was noted in human endometrial adenocarcinomas, and plasmid-driven expression of βKlotho in Ishikawa cells abolished 17β-estradiol-induced EMT via inhibiting ERK1/2 signaling. βKlotho expression and metformin show synergetic effects on the proliferation and the EMT in Ishikawa cells. Furthermore, we demonstrated that the anti-EMT effects of metformin could be partly abolished by introducing Compound C, a specific AMPKα signaling inhibitor. In conclusion, metformin abolishes 17β-estradiol-induced cell proliferation and EMT in endometrial adenocarcinoma cells by upregulating βKlotho expression, inhibiting ERK1/2 signaling, and activating AMPKα signaling. Our study provides novel mechanistic insight into the anti-tumor effects of metformin.

  8. A novel gene's role in an ancient mechanism: secreted Frizzled-related protein 1 is a critical component in the anterior-posterior Wnt signaling network that governs the establishment of the anterior neuroectoderm in sea urchin embryos.

    Science.gov (United States)

    Khadka, Anita; Martínez-Bartolomé, Marina; Burr, Stephanie D; Range, Ryan C

    2018-01-01

    The anterior neuroectoderm (ANE) in many deuterostome embryos (echinoderms, hemichordates, urochordates, cephalochordates, and vertebrates) is progressively restricted along the anterior-posterior axis to a domain around the anterior pole. In the sea urchin embryo, three integrated Wnt signaling branches (Wnt/β-catenin, Wnt/JNK, and Wnt/PKC) govern this progressive restriction process, which begins around the 32- to 60-cell stage and terminates by the early gastrula stage. We previously have established that several secreted Wnt modulators of the Dickkopf and secreted Frizzled-related protein families (Dkk1, Dkk3, and sFRP-1/5) are expressed within the ANE and play important roles in modulating the Wnt signaling network during this process. In this study, we use morpholino and dominant-negative interference approaches to characterize the function of a novel Frizzled-related protein, secreted Frizzled-related protein 1 (sFRP-1), during ANE restriction. sFRP-1 appears to be related to a secreted Wnt modulator, sFRP3/4, that is essential to block Wnt signaling and establish the ANE in vertebrates. Here, we show that the sea urchin sFRP3/4 orthologue is not expressed during ANE restriction in the sea urchin embryo. Instead, our results indicate that ubiquitously expressed maternal sFRP-1 and Fzl1/2/7 signaling act together as early as the 32- to 60-cell stage to antagonize the ANE restriction mechanism mediated by Wnt/β-catenin and Wnt/JNK signaling. Then, starting from the blastula stage, Fzl5/8 signaling activates zygotic sFRP-1 within the ANE territory, where it works with the secreted Wnt antagonist Dkk1 (also activated by Fzl5/8 signaling) to antagonize Wnt1/Wnt8-Fzl5/8-JNK signaling in a negative feedback mechanism that defines the outer ANE territory boundary. Together, these data indicate that maternal and zygotic sFRP-1 protects the ANE territory by antagonizing the Wnt1/Wnt8-Fzl5/8-JNK signaling pathway throughout ANE restriction, providing precise

  9. A novel gene’s role in an ancient mechanism: secreted Frizzled-related protein 1 is a critical component in the anterior–posterior Wnt signaling network that governs the establishment of the anterior neuroectoderm in sea urchin embryos

    Directory of Open Access Journals (Sweden)

    Anita Khadka

    2018-01-01

    Full Text Available Abstract The anterior neuroectoderm (ANE in many deuterostome embryos (echinoderms, hemichordates, urochordates, cephalochordates, and vertebrates is progressively restricted along the anterior–posterior axis to a domain around the anterior pole. In the sea urchin embryo, three integrated Wnt signaling branches (Wnt/β-catenin, Wnt/JNK, and Wnt/PKC govern this progressive restriction process, which begins around the 32- to 60-cell stage and terminates by the early gastrula stage. We previously have established that several secreted Wnt modulators of the Dickkopf and secreted Frizzled-related protein families (Dkk1, Dkk3, and sFRP-1/5 are expressed within the ANE and play important roles in modulating the Wnt signaling network during this process. In this study, we use morpholino and dominant-negative interference approaches to characterize the function of a novel Frizzled-related protein, secreted Frizzled-related protein 1 (sFRP-1, during ANE restriction. sFRP-1 appears to be related to a secreted Wnt modulator, sFRP3/4, that is essential to block Wnt signaling and establish the ANE in vertebrates. Here, we show that the sea urchin sFRP3/4 orthologue is not expressed during ANE restriction in the sea urchin embryo. Instead, our results indicate that ubiquitously expressed maternal sFRP-1 and Fzl1/2/7 signaling act together as early as the 32- to 60-cell stage to antagonize the ANE restriction mechanism mediated by Wnt/β-catenin and Wnt/JNK signaling. Then, starting from the blastula stage, Fzl5/8 signaling activates zygotic sFRP-1 within the ANE territory, where it works with the secreted Wnt antagonist Dkk1 (also activated by Fzl5/8 signaling to antagonize Wnt1/Wnt8–Fzl5/8–JNK signaling in a negative feedback mechanism that defines the outer ANE territory boundary. Together, these data indicate that maternal and zygotic sFRP-1 protects the ANE territory by antagonizing the Wnt1/Wnt8–Fzl5/8–JNK signaling pathway throughout ANE

  10. Aging-related renal injury and inflammation are associated with downregulation of Klotho and induction of RIG-I/NF-κB signaling pathway in senescence-accelerated mice.

    Science.gov (United States)

    Zeng, Yi; Wang, Ping-Han; Zhang, Mao; Du, Jun-Rong

    2016-02-01

    The predominant distribution of the antiaging Klotho protein in both the kidneys and brain may point to its essential role in protecting against dysfunction of the kidney-brain axis during the aging process. Our previous study showed that the downregulation of Klotho was involved in aging-related cognitive impairment in aged senescence-accelerated mouse prone-8 (SAMP8) mice. The present study investigated the potential role of Klotho in aging-associated inflammation and renal injury. Age- and gender-matched groups of SAMP8 mice and their corresponding normal control senescence-accelerated mouse resistant-1 (SAMR1) were used to investigate the potential role of Klotho in aging-associated inflammation and renal injury. Compared with aged SAMR1 controls, early-stage chronic kidney disease (CKD), which is associated with an increase in the urinary albumin-to-creatinine ratio, inflammatory cell infiltration, glomerulosclerosis, and tubulointerstitial fibrosis, was observed in aged SAMP8 mice. Furthermore, the aging-related loss of Klotho-induced activation of the retinoic acid-inducible gene 1/nuclear factor-κB (RIG-I/NF-κB) signaling pathway and subsequent production of the proinflammatory mediators tumor necrosis factor α, interleukin-6, and inducible nitric oxide synthase in the kidneys of aged SAMP8 mice compared with SAMR1 controls. The present results suggest that aging-related inflammation and the development of early-stage CKD are likely associated with the downregulation of Klotho and induction of the RIG-I/NF-κB signaling pathway in 12-month-old SAMP8 mice. Moreover, aged SAMP8 mice with cognitive deficits and renal damage may be a potential mouse model for investigating the kidney-brain axis in the aging process.

  11. Secret-key certificates

    NARCIS (Netherlands)

    S.A. Brands (Stefan)

    1995-01-01

    textabstractThe notion of secret-key certificate schemes is introduced and formalized. As with public-key certificates, triples consisting of a secret key, a corresponding public key, and a secret-key certificate on the public key can only be retrieved by engaging in an issuing protocol with the

  12. Paeoniflorin and liquiritin, two major constituents in Chinese herbal formulas used to treat hyperprolactinemia-associated disorders, inhibits prolactin secretion in prolactinoma cells by different mechanisms.

    Science.gov (United States)

    Wei, Yuanyi; La, Lei; Wang, Lili; Batey, Robert; Wang, Chunxia; Li, Yuhao

    2017-05-23

    Paeoniflorin and liquiritin are major constituents in some Chinese herbal formulas, such as Yiru Tiaojing (YRTJ) Granule (a hospitalized preparation) and Peony-Glycyrrhiza Decoction, used for hyperprolactinemia-associated disorders. To investigate the effect of paeoniflorin and liquiritin on prolactin secretion. The effect of YRTJ Granule on metoclopramide-induced hyperprolactinemia was tested in rats. Paeoniflorin and liquiritin in the YRTJ Granule extract were identified and quantified by HPLC. The effects of paeoniflorin and liquiritin on prolactin secretion were examined in prolactinoma cells that were identified morphologically and by Western blot. The concentration of prolactin was determined by ELISA. The gene expression was analyzed by Western blot. YRTJ Granule ameliorated metoclopramide-induced hyperprolactinemia in rats. The contents of paeoniflorin and liquiritin in YRTJ Granule were 7.43 and 2.05mg/g extract, respectively. Paeoniflorin, liquiritin and bromocriptine (a dopamine D 2 receptor (D 2 R) agonist) decreased prolactin concentration in MMQ cells expressing D 2 R. However, the effect of liquiritin and bromocriptine was abolished in GH3 cells lacking D 2 R expression. Interestingly, paeoniflorin still decreased prolactin concentration in GH3 cells in the same manner. Furthermore, paeoniflorin suppressed prolactin protein expression, and was without effect on D 2 R protein expression in both MMQ and GH3 cells. The present results suggest that paeoniflorin and liquiritin play a role in YRTJ Granule-elicited improvement of hyperprolactinemia. While the effect of liquiritin is D 2 R-dependent, paeoniflorin D 2 R-independently inhibits prolactin secretion in prolactinoma cells that may especially benefit the hyperprolactinemic patients who are refractory to dopaminergic therapies. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

  13. Gastric secretion elicited by conditioning in rats.

    Science.gov (United States)

    Caboclo, José Liberato Ferreira; Cury, Francico de Assis; Borin, Aldenis Albanese; Caboclo, Luís Otávio Sales Ferreira; Ribeiro, Maria Fernanda Sales Caboclo; de Freitas, Pedro José; Andersson, Sven

    2009-01-01

    To investigate whether interdigestive gastric acid secretion can be controlled by a possible memory-related cortical mechanism. To evaluate gastric secretion in rats, we used a methodology that allows gastric juice collection in rats in their habitual conditions (without any restraining) by pairing sound as the conditioning stimulus (CS) and food as the unconditioning stimulus (US). The levels of gastric acid secretion under basal conditions and under sound stimulation were recorded and the circulating gastrin levels determined. When the gastric juice was collected in the course of the conditioning procedure, the results showed that under noise stimulation a significant increase in gastric acid secretion occurred after 10 days of conditioning (p<0.01). The significance was definitively demonstrated after 13 days of conditioning (p<0.001). Basal secretions of the conditioned rats reached a significant level after 16 days of conditioning. The levels of noise-stimulated gastric acid secretion were the highest so far described in physiological experiments carried out in rats and there were no significant increases in the circulating gastrin levels. The results point to the important role played by cortical structures in the control of interdigestive gastric acid secretion in rats. If this mechanism is also present in humans, it may be involved in diseases caused by inappropriate gastric acid secretion during the interprandial periods.

  14. Intracellular mechanism of the action of inhibin on the secretion of follicular stimulating hormone and of luteinizing hormone induced by LH-RH in vitro

    Science.gov (United States)

    Lecomte-Yerna, M. J.; Hazee-Hagelstein, M. T.; Charlet-Renard, C.; Franchimont, P.

    1982-01-01

    The FSH secretion-inhibiting action of inhibin in vitro under basal conditions and also in the presence of LH-RH is suppressed by the addition of MIX, a phosphodiesterase inhibitor. In the presence of LH-RH, inhibin reduces significantly the intracellular level of cAMP in isolated pituitary cells. In contrast, the simultaneous addition of MIX and inhibin raises the cAMP level, and this stimulation is comparable to the increase observed when MIX is added alone. These observations suggest that one mode of action of inhibin could be mediated by a reduction in cAMP within the pituitary gonadotropic cell.

  15. Förster Resonance Energy Transfer (FRET as a Tool for Dissecting the Molecular Mechanisms for Maturation of the Shigella Type III Secretion Needle Tip Complex

    Directory of Open Access Journals (Sweden)

    William D. Picking

    2012-11-01

    Full Text Available Förster resonance energy transfer (FRET provides a powerful tool for monitoring intermolecular interactions and a sensitive technique for studying Å-level protein conformational changes. One system that has particularly benefited from the sensitivity and diversity of FRET measurements is the maturation of the Shigella type III secretion apparatus (T3SA needle tip complex. The Shigella T3SA delivers effector proteins into intestinal cells to promote bacterial invasion and spread. The T3SA is comprised of a basal body that spans the bacterial envelope and a needle with an exposed tip complex that matures in response to environmental stimuli. FRET measurements demonstrated bile salt binding by the nascent needle tip protein IpaD and also mapped resulting structural changes which led to the recruitment of the translocator IpaB. At the needle tip IpaB acts as a sensor for host cell contact but prior to secretion, it is stored as a heterodimeric complex with the chaperone IpgC. FRET analyses showed that chaperone binding to IpaB’s N-terminal domain causes a conformational change in the latter. These FRET analyses, with other biophysical methods, have been central to understanding T3SA maturation and will be highlighted, focusing on the details of the FRET measurements and the relevance to this particular system.

  16. Secrets and Social Influence

    OpenAIRE

    Cowan, Sarah Kiva

    2013-01-01

    Each of us has secrets of our own and we know others' secrets too. We share these secrets with some people and we keep these secrets from other people. This affects what we know about each other and how, in turn, we are influenced by each other. Social science scholars have consistently found that people influence each other with regard to matters that can be observed like dropping out of school, weight gain or family structures. But of course, there are whole swaths of social life that are u...

  17. Muscle atrophy in patients wirh ckd results from fgf23/klotho-mediated supression of insulin/igf-i signaling

    Directory of Open Access Journals (Sweden)

    Shinsuke Kido

    2012-06-01

    Full Text Available Muscle atrophy is a significant consequence of chronic kidney disease (CKD that increases a patient’s risk of mortality and decrease their quality of life. In CKD patients, the circulation levels of FGF23 are significantly increased, but the exact pathological significance of the increase and relationship between FGF23 and muscle atrophy are not clear. Because of Klohto, acts as a co-receptor of FGF23 is detectable in limited tissues including in kidney and brain, but not in skeletal muscles. In contrast, recently reports indicated that the extracellular domain of klohto is cleavage for some reason on the cell surface and detected in the blood in animals. In this study, we attempted to identify the causative factors responsible for the shedding of Klotho, and whether both FGF23 and Klohto induced muscle atrophy via reduction of insulin/IGF-I signaling. We first investigated by treating kidney cells with various factors related in pathological factors in CKD. As a result, we found that advanced glycation endproducts (AGEs, an accumulated in patients with CKD and diabetes mellitus, increases shedding of Klohto in kidney cells. It is common knowledge that insulin/IGF-I signaling is necessary for normal skeletal growth. As a result, we showed that both FGF23 and Klohto inhibited differentiation of cultured skeletal muscle cells through down-regulation of insulin/IGF-I signaling. These observations suggested a divergent role of FGF23 and soluble klohto in the regulation of skeletal muscle differentiation and thereby muscle atrophy under pathological conditioned in CKD patients. Our results further imply that FGF23/Klohto may serve a new therapeutic target for CKD-induced muscle atrophy.

  18. Dynamic quantum secret sharing

    International Nuclear Information System (INIS)

    Jia, Heng-Yue; Wen, Qiao-Yan; Gao, Fei; Qin, Su-Juan; Guo, Fen-Zhuo

    2012-01-01

    In this Letter we consider quantum secret sharing (QSS) between a sender and a dynamic agent group, called dynamic quantum secret sharing (DQSS). In the DQSS, the change of the agent group is allowable during the procedure of sharing classical and quantum information. Two DQSS schemes are proposed based on a special kind of entangled state, starlike cluster states. Without redistributing all the shares, the changed agent group can reconstruct the sender's secret by their cooperation. Compared with the previous quantum secret sharing scheme, our schemes are more flexible and suitable for practical applications. -- Highlights: ► We consider quantum secret sharing between a sender and a dynamic agent group, called dynamic quantum secret sharing (DQSS). ► In the DQSS, the change of the agent group is allowable during the procedure of sharing classical and quantum information. ► Two DQSS schemes are proposed based on a special kind of entangled state, starlike cluster states. ► Without redistributing all the shares, the changed agent group can reconstruct the sender's secret by their cooperation. ► Compared with the previous quantum secret sharing scheme, our schemes are more flexible and suitable for practical applications.

  19. Cell Secretion: Current Structural and Biochemical Insights

    Directory of Open Access Journals (Sweden)

    Saurabh Trikha

    2010-01-01

    Full Text Available Essential physiological functions in eukaryotic cells, such as release of hormones and digestive enzymes, neurotransmission, and intercellular signaling, are all achieved by cell secretion. In regulated (calcium-dependent secretion, membrane-bound secretory vesicles dock and transiently fuse with specialized, permanent, plasma membrane structures, called porosomes or fusion pores. Porosomes are supramolecular, cup-shaped lipoprotein structures at the cell plasma membrane that mediate and control the release of vesicle cargo to the outside of the cell. The sizes of porosomes range from 150nm in diameter in acinar cells of the exocrine pancreas to 12nm in neurons. In recent years, significant progress has been made in our understanding of the porosome and the cellular activities required for cell secretion, such as membrane fusion and swelling of secretory vesicles. The discovery of the porosome complex and the molecular mechanism of cell secretion are summarized in this article.

  20. Secret quality of love.

    Science.gov (United States)

    Strachan-Hall, Elaine

    2016-09-01

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

  1. The glucocorticoid/aggression relationship in animals and humans: an analysis sensitive to behavioral characteristics, glucocorticoid secretion patterns, and neural mechanisms.

    Science.gov (United States)

    Haller, József

    2014-01-01

    Glucocorticoids control a wide array of biological processes from glucose homeostasis to neuronal function. The mechanisms mediating their effects are similarly varied and include rapid and transient nongenomic effects on calcium trafficking, various neurotransmitter receptors, and other membrane/cytoplasmic proteins, as well as slowly developing but durable genomic effects that are mediated by a large number of glucocorticoid-sensitive genes that are affected after variable lag-times. Given this complexity, we suggest that the aggression/glucocorticoid relationship cannot be reduced to the simple "stimulation/inhibition" question. Here, we review the effects of glucocorticoids on aggression by taking into account the complexities of glucocorticoid actions. Acute and chronic effects were differentiated because these are mediated by different mechanisms. The effects of chronic increases and decreases in glucocorticoid production were discussed separately, because the activation of mechanisms that are not normally activated and the loss of normal functions should not be confounded. Findings in healthy/normal subjects and those obtained in subjects that show abnormal forms of behavior or psychopathologies were also differentiated, because the effects of glucocorticoids are indirect, and largely depend on the properties of neurons they act upon, which are altered in subjects with psychopathologies. In addition, the conditions of glucocorticoid measurements were also thoroughly evaluated. Although the role of glucocorticoids in aggression is perceived as controversial by many investigators, a detailed analysis that is sensitive to glucocorticoid and behavioral measure as well as to the mediating mechanism suggests that this role is rather clear-cut; moreover, there is a marked similarity between animal and human findings.

  2. Evaluation of the effects of quercetin on damaged salivary secretion.

    Directory of Open Access Journals (Sweden)

    Ayako Takahashi

    Full Text Available With the aim of discovering an effective method to treat dry mouth, we analyzed the effects of quercetin on salivary secretion and its mechanism of action. We created a mouse model with impaired salivary secretion by exposure to radiation and found that impaired secretion is suppressed by quercetin intake. Moreover, secretion levels were enhanced in quercetin-fed normal mice. To elucidate the mechanisms of these effects on salivary secretion, we conducted an analysis using mouse submandibular gland tissues, a human salivary gland epithelial cell line (HSY, and mouse aortic endothelial cells (MAECs. The results showed that quercetin augments aquaporin 5 (AQP5 expression and calcium uptake, and suppresses oxidative stress and inflammatory responses induced by radiation exposure, suggesting that quercetin intake may be an effective method to treat impaired salivary secretion.

  3. Experimental Study on Gastric Juice Secretion by ...

    African Journals Online (AJOL)

    管理平台

    2012-05-29

    May 29, 2012 ... To explore the effect and mechanism on the physiological functions of stomach by electroacupunctue at zusanli (STOMACH-36), the changes of the gastric electrical frequency and amplitude, and the flux of gastric juice secretion were observed with modern apparatus, when electroacupuncture at zusanli ...

  4. Regulation of gut hormone secretion. Studies using isolated perfused intestines

    DEFF Research Database (Denmark)

    Svendsen, Berit; Holst, Jens Juul.

    2016-01-01

    carbohydrate, protein and lipid. This review focuses on stimulators of gut hormone secretion, the mechanisms involved, and in particular models used to investigate secretion. A major break-through in this field was the development of methods to identify and isolate specific hormone producing cells, which allow...

  5. A Public Secret

    DEFF Research Database (Denmark)

    Bregnbæk, Susanne

    2011-01-01

    This article is based on anthropological fieldwork undertaken at two elite universities in Beijing. It addresses the paradoxical situation of the many instances of suicide among Chinese elite university students in Beijing, which constitute a public secret. The pressure of education weighs heavily...

  6. MONA Implementation Secrets

    DEFF Research Database (Denmark)

    Klarlund, Nils; Møller, Anders; Schwartzbach, Michael Ignatieff

    2002-01-01

    a period of six years. Compared to the first naive version, the present tool is faster by several orders of magnitude. This speedup is obtained from many different contributions working on all levels of the compilation and execution of formulas. We present a selection of implementation "secrets" that have...

  7. Type VI secretion system.

    Science.gov (United States)

    Salomon, Dor; Orth, Kim

    2015-03-30

    Bacteria employ a variety of tools to survive in a competitive environment. Salomon and Orth describe one such tool-the Type 6 Secretion Systems used by bacteria to deliver a variety of toxins into competing cells. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Trade-Secret Dispute.

    Science.gov (United States)

    Blumenstyk, Goldie

    1994-01-01

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

  9. Proton pump inhibitors inhibit pancreatic secretion

    DEFF Research Database (Denmark)

    Wang, Jing; Barbuskaite, Dagne; Tozzi, Marco

    2015-01-01

    The mechanism by which pancreas secretes high HCO3- has not been fully resolved. This alkaline secretion, formed in pancreatic ducts, can be achieved by transporting HCO3- from serosa to mucosa or by moving H+ in the opposite direction. The aim of the present study was to determine whether H+/K+-...... it may provide a protective pH buffer zone and K+ recirculation. Furthermore, it seems relevant to re-evaluate whether PPIs should be used in treatment therapies where pancreatic functions are already compromised....

  10. Identification of genes encoding the type IX secretion system and secreted proteins in Flavobacterium columnare IA-S-4

    Science.gov (United States)

    Flavobacterium columnare, a member of the phylum Bacteroidetes, causes columnaris disease in wild and aquaculture-reared freshwater fish. The mechanisms responsible for columnaris disease are not known. Many members of the phylum Bacteroidetes use type IX secretion systems (T9SSs) to secrete enzymes...

  11. Unique substrates secreted by the type VI secretion system of Francisella tularensis during intramacrophage infection.

    Science.gov (United States)

    Bröms, Jeanette E; Meyer, Lena; Sun, Kun; Lavander, Moa; Sjöstedt, Anders

    2012-01-01

    Gram-negative bacteria have evolved sophisticated secretion machineries specialized for the secretion of macromolecules important for their life cycles. The Type VI secretion system (T6SS) is the most widely spread bacterial secretion machinery and is encoded by large, variable gene clusters, often found to be essential for virulence. The latter is true for the atypical T6SS encoded by the Francisella pathogenicity island (FPI) of the highly pathogenic, intracellular bacterium Francisella tularensis. We here undertook a comprehensive analysis of the intramacrophage secretion of the 17 FPI proteins of the live vaccine strain, LVS, of F. tularensis. All were expressed as fusions to the TEM β-lactamase and cleavage of the fluorescent substrate CCF2-AM, a direct consequence of the delivery of the proteins into the macrophage cytosol, was followed over time. The FPI proteins IglE, IglC, VgrG, IglI, PdpE, PdpA, IglJ and IglF were all secreted, which was dependent on the core components DotU, VgrG, and IglC, as well as IglG. In contrast, the method was not directly applicable on F. novicida U112, since it showed very intense native β-lactamase secretion due to FTN_1072. Its role was proven by ectopic expression in trans in LVS. We did not observe secretion of any of the LVS substrates VgrG, IglJ, IglF or IglI, when tested in a FTN_1072 deficient strain of F. novicida, whereas IglE, IglC, PdpA and even more so PdpE were all secreted. This suggests that there may be fundamental differences in the T6S mechanism among the Francisella subspecies. The findings further corroborate the unusual nature of the T6SS of F. tularensis since almost all of the identified substrates are unique to the species.

  12. Melatonin Secretion Pattern in Critically Ill Patients

    DEFF Research Database (Denmark)

    Boyko, Yuliya; Holst, René; Jennum, Poul

    2017-01-01

    Critically ill patients have abnormal circadian and sleep homeostasis. This may be associated with higher morbidity and mortality. The aims of this pilot study were (1) to describe melatonin secretion in conscious critically ill mechanically ventilated patients and (2) to describe whether melatonin...... secretion and sleep patterns differed in these patients with and without remifentanil infusion. Eight patients were included. Blood-melatonin was taken every 4th hour, and polysomnography was carried out continually during a 48-hour period. American Academy of Sleep Medicine criteria were used for sleep...... scoring if sleep patterns were identified; otherwise, Watson's classification was applied. As remifentanil was periodically administered during the study, its effect on melatonin and sleep was assessed. Melatonin secretion in these patients followed a phase-delayed diurnal curve. We did not observe any...

  13. Extracellular secretion of recombinant proteins

    Science.gov (United States)

    Linger, Jeffrey G.; Darzins, Aldis

    2014-07-22

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

  14. Pathophysiology of glucagon secretion

    International Nuclear Information System (INIS)

    Boettger, J.; Pabst, H.W.

    1980-01-01

    Pathophysiology of glucagon secretion is reviewed in brief separating hyperglucagonemic from hypoclucagonemic states. Many questions concerning the role of glucagon in diabetes mellitus and in other diseases are still unresolved. The clucagon RIA is of clinical significance in a few diseases like glucagonoma, which may present without symptoms of the 'glucagonoma syndrome', the probably very rare hyperglucagonemia and some of the spontaneous hypoglycemias. Glucagon secretion may be evaluated by the determination of fasting immunoreactive glucagon (IRG) and by appropriate function tests as stimulation with i.v. arginine and suppression with oral glucose. However, the glucagon RIA at present is not a routine method, although commercial kits are available. Many pitfalls of radioimmunological glucagon determination still exist. (orig.) [de

  15. Bucarest, Strictement Secret

    Directory of Open Access Journals (Sweden)

    Ionela Mihai

    2010-07-01

    Full Text Available L’émission Bucarest, strictement secret représente un documentaire organisésous la forme d’une série télé, qui dépeint le Bucarest à partir de deux perspectives: de l’histoire, de la conte et du lieu. La valeur d’une cité réside dans l’existence d’une mystique, d’un romantisme abscons, à part et des caractères empruntés de drames de Shakespeare, mystérieux, serrés d’angoisse et des secrets qui assombrissent leur existence. Par conséquence, le rôle du metteur en scène est de dévoiler leur vraie identité et de remettre en place, autant que possible, la vérité.

  16. Proactive quantum secret sharing

    Science.gov (United States)

    Qin, Huawang; Dai, Yuewei

    2015-11-01

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

  17. Portillo's State Secrets: Mysteries

    OpenAIRE

    Clarke, David

    2015-01-01

    Blog/article commissioned by The National Archives to accompany Episode 4 of the BBC 2 series 'Portillo's State Secrets' (BBC 2, 26 March 2015). The article discusses and places in historical context the contents of Metropolitan Police files on the Jack the Ripper murders; the investigation of the 'Kitchener Coffin Hoax' of WW1 and the Ministry of Defence file on the so-called Rendlesham Forest UFO incident at RAF Woodbridge in 1980.

  18. The Secret Suburb

    DEFF Research Database (Denmark)

    Bech-Danielsen, Claus

    2015-01-01

    The ability to be ‘invisible’ seems to be an important quality in relation to a summerhouse. In fact, summerhouses can be said to be ‘invisible’ in a double sense. As I will explore in this chapter, summerhouses are neglected in planning and partly forgotten in Danish building regulations, at the......, at the same time as their owners like to see summerhouses as hidden places where they can live secret lives, hidden away from the modern world....

  19. Lipids in airway secretions

    International Nuclear Information System (INIS)

    Bhaskar, K.R.; DeFeudis O'Sullivan, D.; Opaskar-Hincman, H.; Reid, L.M.

    1987-01-01

    Lipids form a significant portion of airway mucus yet they have not received the same attention that epithelial glycoproteins have. We have analysed, by thin layer chromatography, lipids present in airway mucus under 'normal' and hypersecretory (pathological) conditions.The 'normals' included (1) bronchial lavage obtained from healthy human volunteers and from dogs and (2) secretions produced ''in vitro'' by human (bronchial) and canine (tracheal) explants. Hypersecretory mucus samples included (1) lavage from dogs made bronchitic by exposure to SO 2 , (2) bronchial aspirates from acute and chronic tracheostomy patients, (3) sputum from patients with cystic fibrosis and chronic bronchitis and (4) postmortem secretions from patients who died from sudden infant death syndrome (SIDS) or from status asthmaticus. Cholesterol was found to be the predominant lipid in 'normal' mucus with lesser amounts of phospholipids. No glycolipids were detected. In the hypersecretory mucus, in addition to neutral and phospholipids, glycolipids were present in appreciable amounts, often the predominant species, suggesting that these may be useful as markers of disease. Radioactive precursors 14 C acetate and 14 C palmitate were incorporated into lipids secreted ''in vitro'' by canine tracheal explants indicating that they are synthesised by the airway. (author)

  20. Ghrelin drives GH secretion during fasting in man

    NARCIS (Netherlands)

    A.F. Muller (Alex); S.W.J. Lamberts (Steven); L.J. Hofland (Leo); M. Bidlingmaier (Martin); C.J. Strasburger; E. Ghigo (Ezio); A-J. van der Lely (Aart-Jan); J.A.M.J.L. Janssen (Joseph); P.M. van Koetsveld (Peter)

    2002-01-01

    textabstractOBJECTIVES: In humans, fasting leads to elevated serum GH concentrations. Traditionally, changes in hypothalamic GH-releasing hormone and somatostatin release are considered as the main mechanisms that induce this elevated GH secretion during fasting. Ghrelin is an

  1. Dynamic secrets in communication security

    CERN Document Server

    Xiao, Sheng; Towsley, Donald

    2013-01-01

    Dynamic secrets are constantly generated and updated from messages exchanged between two communication users. When dynamic secrets are used as a complement to existing secure communication systems, a stolen key or password can be quickly and automatically reverted to its secret status without disrupting communication. 'Dynamic Secrets in Communication Security' presents unique security properties and application studies for this technology. Password theft and key theft no longer pose serious security threats when parties frequently use dynamic secrets. This book also illustrates that a dynamic

  2. Windows 8 secrets

    CERN Document Server

    Thurrott, Paul

    2012-01-01

    Tips, tricks, treats, and secrets revealed on Windows 8 Microsoft is introducing a major new release of its Windows operating system, Windows 8, and what better way to learn all its ins and outs than from two internationally recognized Windows experts and Microsoft insiders, authors Paul Thurrott and Rafael Rivera? They cut through the hype to get at useful information you'll not find anywhere else, including what role this new OS plays in a mobile and tablet world. Regardless of your level of knowledge, you'll discover little-known facts about how things work, what's new and different, and h

  3. Glucagon-like peptide 1 (GLP-1) suppresses ghrelin levels in humans via increased insulin secretion

    DEFF Research Database (Denmark)

    Hagemann, Dirk; Holst, Jens Juul; Gethmann, Arnica

    2007-01-01

    INTRODUCTION: Ghrelin is an orexigenic peptide predominantly secreted by the stomach. Ghrelin plasma levels rise before meal ingestion and sharply decline afterwards, but the mechanisms controlling ghrelin secretion are largely unknown. Since meal ingestion also elicits the secretion of the incre...... postprandial period at supraphysiological plasma levels. Most likely, these effects are indirectly mediated through its insulinotropic action. The GLP-1-induced suppression of ghrelin secretion might be involved in its anorexic effects....

  4. On Converting Secret Sharing Scheme to Visual Secret Sharing Scheme

    Directory of Open Access Journals (Sweden)

    Wang Daoshun

    2010-01-01

    Full Text Available Abstract Traditional Secret Sharing (SS schemes reconstruct secret exactly the same as the original one but involve complex computation. Visual Secret Sharing (VSS schemes decode the secret without computation, but each share is m times as big as the original and the quality of the reconstructed secret image is reduced. Probabilistic visual secret sharing (Prob.VSS schemes for a binary image use only one subpixel to share the secret image; however the probability of white pixels in a white area is higher than that in a black area in the reconstructed secret image. SS schemes, VSS schemes, and Prob. VSS schemes have various construction methods and advantages. This paper first presents an approach to convert (transform a -SS scheme to a -VSS scheme for greyscale images. The generation of the shadow images (shares is based on Boolean XOR operation. The secret image can be reconstructed directly by performing Boolean OR operation, as in most conventional VSS schemes. Its pixel expansion is significantly smaller than that of VSS schemes. The quality of the reconstructed images, measured by average contrast, is the same as VSS schemes. Then a novel matrix-concatenation approach is used to extend the greyscale -SS scheme to a more general case of greyscale -VSS scheme.

  5. Ability of multicellular salt glands in Tamarix species to secrete Na+ and K+ selectively.

    Science.gov (United States)

    Ma, Haiyan; Tian, Changyan; Feng, Gu; Yuan, Junfeng

    2011-03-01

    The present study aimed to determine the mechanism of cation-selective secretion by multicellular salt glands. Using a hydroponic culture system, the secretion and accumulation of Na(+) and K(+) in Tamarix ramosissima and T. laxa under different salt stresses (NaCl, KCl and NaCl+KCl) were studied. Additionally, the effects of salt gland inhibitors (orthovanadate, Ba(2+), ouabain, tetraethylammonium (TEA) and verapamil) on Na(+) and K(+) secretion and accumulation were examined. Treatment with NaCl (at 0-200 mmol L(-1) levels) significantly increased Na(+) secretion, whereas KCl treatment (at 0-200 mmol L(-1) levels) significantly increased K(+) secretion. The ratio of secretion to accumulation of Na(+) was higher than that of K(+). The changes in Na(+) and K(+) secretion differed after adding different ions into the single-salt solutions. Addition of NaCl to the KCl solution (at 100 mmol L(-1) level, respectively) led to a significant decrease in K(+) secretion rate, whereas addition of KCl to the NaCl solution (at 100 mmol L(-1) level, respectively) had little impact on the Na(+) secretion rate. These results indicated that Na+ secretion in Tamarix was highly selective. In addition, Na(+) secretion was significantly inhibited by orthovanadate, ouabain, TEA and verapamil, and K(+) secretion was significantly inhibited by ouabain, TEA and verapamil. The different impacts of orthovanadate on Na(+) and K(+) secretion might be the primary cause for the different Na(+) and K(+) secretion abilities of multicellular salt glands in Tamarix.

  6. Androgen secreting adrenocortical tumours.

    Science.gov (United States)

    Wolthers, O D; Cameron, F J; Scheimberg, I; Honour, J W; Hindmarsh, P C; Savage, M O; Stanhope, R G; Brook, C G

    1999-01-01

    Androgen secreting adrenocortical tumours are rare in children and the determination of their malignant potential can be difficult. To assess the presentation, histology, and clinical behaviour of these tumours. Two tertiary referral centres. Retrospective analysis of children diagnosed with an androgen secreting adrenocortical tumour between 1976 and 1996. Twenty three girls and seven boys aged 0-14 years. Pubic hair was observed in all children, clitoromegaly or growth of the phallus in 23 children, acceleration of linear growth in 22 children, and advanced bone age (> 1.5 years) in 18 children. Hypersecretion of androgens was detected by assessment of serum androgen concentrations alone in four patients and by 24 hour urine steroid excretion profiles in 22 patients. All 16 tumours measuring 10 cm were malignant. Histological slides were available for reassessment in 25 children. Although mitoses and necrosis were more characteristic of tumours with malignant behaviour, no exclusive histological features of malignancy were seen. Histological criteria for malignancy are not reliable, whereas tumour size is important in assessing malignant potential.

  7. A quantum secret-sharing protocol with fairness

    International Nuclear Information System (INIS)

    Liu, Feng; Qin, Su-Juan; Wen, Qiao-Yan

    2014-01-01

    A quantum secret-sharing (QSS) protocol consists of two main phases, called sharing and reconstruction. In the first phase, the dealer selects a secret, divides it into several shares, and sends each participant its share securely with a quantum channel. In the second phase, the participants run an interactive protocol in order to reconstruct the secret. If the participants can communicate via a broadcast channel, they can show their shares and learn the secrets simultaneously. So what happens if the channel is not simultaneous? In this paper, we propose a QSS protocol with cheaters by using partially and maximally entangled states. A secure and fair reconstruction mechanism is designed, in a way that each participant can learn or cannot learn the secret simultaneously. (papers)

  8. Protecting Trade Secrets in Canada.

    Science.gov (United States)

    Courage, Noel; Calzavara, Janice

    2015-05-18

    Patents in the life sciences industries are a key form of intellectual property (IP), particularly for products such as brand-name drugs and medical devices. However, trade secrets can also be a useful tool for many types of innovations. In appropriate cases, trade secrets can offer long-term protection of IP for a lower financial cost than patenting. This type of protection must be approached with caution as there is little room for error when protecting a trade secret. Strong agreements and scrupulous security can help to protect the secret. Once a trade secret is disclosed to the public, it cannot be restored as the owner's property; however, if the information is kept from the public domain, the owner can have a property right of unlimited duration in the information. In some situations patents and trade secrets may be used cooperatively to protect innovation, particularly for manufacturing processes. Copyright © 2015 Cold Spring Harbor Laboratory Press; all rights reserved.

  9. Unconventional protein secretion (UPS) pathways in plants.

    Science.gov (United States)

    Ding, Yu; Robinson, David G; Jiang, Liwen

    2014-08-01

    As in yeast and mammalian cells, novel unconventional protein secretion (UPS) or unconventional membrane trafficking pathways are now known to operate in plants. UPS in plants is generally associated with stress conditions such as pathogen attack, but little is known about its underlying mechanism and function. Here, we present an update on the current knowledge of UPS in the plants in terms of its transport pathways, possible functions and its relationship to autophagy. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. [Impact of anemia correction on the production of the circulating morphogenetic protein α-Klotho in patients with Stages 3B-4 chronic kidney disease: A new direction of cardionephroprotection].

    Science.gov (United States)

    Milovanov, Yu S; Mukhin, N A; Kozlovskaya, L V; Milovanova, S Yu; Markina, M M

    2016-01-01

    To investigate the impact of anemia correction with erythropoiesis stimulants on the serum level of the circulating morphogenetic protein α-Klotho in patients with Stages 3B--4 chronic kidney disease (CKD). 64 patients aged 42±8 years with Stages 3B--4 nondiabetic CKD were examined and divided into 2 groups: 1) 32 patients with anemia (the target hemoglobin levels could be achieved and kept with erythropoietin and iron saccharate in 20 patients (Group A) and those could not be done in 12 patients (Group 1B). A control group (Group 2) consisted of 32 non-anemic patients matched for gender, age, and degree of a glomerular filtration rate (GFR) reduction. Along with iron exchange indicators, the time course of changes in serum Klotho levels were examined in all the 64 patients during screening and one year after the end of the study. For correction of anemia, 32 patients with this condition (Groups 1A and 1B) took short-acting epoetin (hypodermic recormon 2,000 IU thrice per week + iron (intravenous venofer 5 ml of 100 mg once per week)) under control of hemoglobin levels and serum transferrin iron and ferritin saturation. After achieving the target hemoglobin level of 110-120 g/l, for its keeping, all the patients received, instead of short-acting epoetin, long-acting hypodermic darbepoetin-α 1.5 µg once every 2 months and intravenous iron saccharate 100 mg once every 2 weeks. Among the 32 anemic patients in Group 1, 20 (63%) (Group 1 A) could achieve the target hemoglobin level (110--120 g/l) and maintain it within this range, by performing therapy with epoitin-β + iron saccharate; anemia (the hemoglobin level of anemia, left ventricular hypertrophy, and heart failure), but also a pathogenetic factor of CKD progression. Anemia correction with erythropoiesis stimulants has been shown to enhance the renal and extrarenal production of α-Klotho.

  11. Catecholamine Secretion from Individual Cells

    National Research Council Canada - National Science Library

    Wightman, R

    1998-01-01

    .... Many cells, including neurons, communicate by secretion of chemical substances by exocytosis where substances are extruded into the extracellular space following fusion of the vesicle and plasma membranes...

  12. Mechanism

    Directory of Open Access Journals (Sweden)

    Yao Yu

    2010-01-01

    Full Text Available The kinematics analysis method of a novel 3-DOF wind tunnel mechanism based on cable-driven parallel mechanism is provided. Rodrigues' parameters are applied to express the transformation matrix of the wire-driven mechanism in the paper. The analytical forward kinematics model is described as three quadratic equations using three Rodridgues' parameters based on the fundamental theory of parallel mechanism. Elimination method is used to remove two of the variables, so that an eighth-order polynomial with one variable is derived. From the equation, the eight sets of Rodridgues' parameters and corresponding Euler angles for the forward kinematical problem can be obtained. In the end, numerical example of both forward and inverse kinematics is included to demonstrate the presented forward-kinematics solution method. The numerical results show that the method for the position analysis of this mechanism is effective.

  13. Regulated Mucin Secretion from Airway Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Kenneth Bruce Adler

    2013-09-01

    Full Text Available Secretory epithelial cells of the proximal airways synthesize and secrete gel-forming polymeric mucins. The secreted mucins adsorb water to form mucus that is propelled by neighboring ciliated cells, providing a mobile barrier which removes inhaled particles and pathogens from the lungs. Several features of the intracellular trafficking of mucins make the airway secretory cell an interesting comparator for the cell biology of regulated exocytosis. Polymeric mucins are exceedingly large molecules (up to 3x10^6 D per monomer whose folding and initial polymerization in the ER requires the protein disulfide isomerase Agr2. In the Golgi, mucins further polymerize to form chains and possibly branched networks comprising more than 20 monomers. The large size of mucin polymers imposes constraints on their packaging into transport vesicles along the secretory pathway. Sugar side chains account for >70% of the mass of mucins, and their attachment to the protein core by O-glycosylation occurs in the Golgi. Mature polymeric mucins are stored in large secretory granules ~1 um in diameter. These are translocated to the apical membrane to be positioned for exocytosis by cooperative interactions among MARCKS, cysteine string protein (CSP, HSP70 and the cytoskeleton. Mucin granules undergo exocytic fusion with the plasma membrane at a low basal rate and a high stimulated rate. Both rates are mediated by a regulated exocytic mechanism as indicated by phenotypes in both basal and stimulated secretion in mice lacking Munc13-2, a sensor of the second messengers calcium and diacylglycerol (DAG. Basal secretion is induced by low levels of activation of P2Y2 purinergic and A3 adenosine receptors by extracellular ATP released in paracrine fashion and its metabolite adenosine. Stimulated secretion is induced by high levels of the same ligands, and possibly by inflammatory mediators as well. Activated receptors are coupled to phospholipase C by Gq, resulting in the

  14. Secreted proteases from pathogenic fungi.

    Science.gov (United States)

    Monod, Michel; Capoccia, Sabrina; Léchenne, Barbara; Zaugg, Christophe; Holdom, Mary; Jousson, Olivier

    2002-10-01

    Many species of human pathogenic fungi secrete proteases in vitro or during the infection process. Secreted endoproteases belong to the aspartic proteases of the pepsin family, serine proteases of the subtilisin family, and metalloproteases of two different families. To these proteases has to be added the non-pepsin-type aspartic protease from Aspergillus niger and a unique chymotrypsin-like protease from Coccidioides immitis. Pathogenic fungi also secrete aminopeptidases, carboxypeptidases and dipeptidyl-peptidases. The function of fungal secreted proteases and their importance in infections vary. It is evident that secreted proteases are important for the virulence of dermatophytes since these fungi grow exclusively in the stratum corneum, nails or hair, which constitutes their sole nitrogen and carbon sources. The aspartic proteases secreted by Candida albicans are involved in the adherence process and penetration of tissues, and in interactions with the immune system of the infected host. For Aspergillus fumigatus, the role of proteolytic activity has not yet been proved. Although the secreted proteases have been intensively investigated as potential virulence factors, knowledge on protease substrate specificities is rather poor and few studies have focused on the research of inhibitors. Knowledge of substrate specificities will increase our understanding about the action of each protease secreted by pathogenic fungi and will help to determine their contribution to virulence.

  15. Candida albicans Secreted Aspartyl Proteinases in Virulence and Pathogenesis

    OpenAIRE

    Naglik, Julian R.; Challacombe, Stephen J.; Hube, Bernhard

    2003-01-01

    Candida albicans is the most common fungal pathogen of humans and has developed an extensive repertoire of putative virulence mechanisms that allows successful colonization and infection of the host under suitable predisposing conditions. Extracellular proteolytic activity plays a central role in Candida pathogenicity and is produced by a family of 10 secreted aspartyl proteinases (Sap proteins). Although the consequences of proteinase secretion during human infections is not precisely known,...

  16. A Finite Equivalence of Verifiable Multi-secret Sharing

    Directory of Open Access Journals (Sweden)

    Hui Zhao

    2012-02-01

    Full Text Available We give an abstraction of verifiable multi-secret sharing schemes that is accessible to a fully mechanized analysis. This abstraction is formalized within the applied pi-calculus by using an equational theory which characterizes the cryptographic semantics of secret share. We also present an encoding from the equational theory into a convergent rewriting system, which is suitable for the automated protocol verifier ProVerif. Based on that, we verify the threshold certificate protocol in ProVerif.

  17. The age-related changes of dietary phosphate responsiveness in plasma 1,25-dihydroxyvitamin D levels and renal Cyp27b1 and Cyp24a1 gene expression is associated with renal α-Klotho gene expression in mice.

    Science.gov (United States)

    Yoshikawa, Ryouhei; Yamamoto, Hironori; Nakahashi, Otoki; Kagawa, Tomohiro; Tajiri, Mari; Nakao, Mari; Fukuda, Shiori; Arai, Hidekazu; Masuda, Masashi; Iwano, Masayuki; Takeda, Eiji; Taketani, Yutaka

    2018-01-01

    In this study, we investigated the relationship between age-related changes in renal α-Klotho gene expression, vitamin D metabolism and the responsiveness of dietary phosphate in 1, 2 and 13 month-old mice fed a high phosphate (phosphate 1.2%) diet or low phosphate (phosphate 0.02%) diet for 5 days. We found that 1,25-dihydroxyvitamin D levels in plasma were significantly lower in the high phosphate group than the low phosphate group for 1 and 2 month-old mice, but not 13 month-old mice. In addition, in the high phosphate group plasma 1,25-dihydroxyvitamin D levels were decreased in 2 month-old mice relative to 1 month-old mice, but 13 month-old mice had higher levels than 2 month-old mice. In fact, plasma 1,25-dihydroxyvitamin D levels showed a significant correlation with vitamin D metabolism gene Cyp27b1 and Cyp24a1 mRNA expression in the high phosphate group. Interestingly, renal α -Klotho mRNA and protein levels were significant change with age. Furthermore, α -Klotho mRNA expression showed a significant negative correlation with plasma 1,25-dihydroxyvitamin D levels in the high phosphate group. Our results suggest that age-related alterations in renal α-Klotho expression could affect the responsiveness of dietary phosphate to vitamin D metabolism.

  18. Pheochromocytomas and secreting paragangliomas

    Directory of Open Access Journals (Sweden)

    Gimenez-Roqueplo Anne-Paule

    2006-12-01

    Full Text Available Abstract Catecholamine-producing tumors may arise in the adrenal medulla (pheochromocytomas or in extraadrenal chromaffin cells (secreting paragangliomas. Their prevalence is about 0.1% in patients with hypertension and 4% in patients with a fortuitously discovered adrenal mass. An increase in the production of catecholamines causes symptoms (mainly headaches, palpitations and excess sweating and signs (mainly hypertension, weight loss and diabetes reflecting the effects of epinephrine and norepinephrine on α- and β-adrenergic receptors. Catecholamine-producing tumors mimic paroxysmal conditions with hypertension and/or cardiac rhythm disorders, including panic attacks, in which sympathetic activation linked to anxiety reproduces the same signs and symptoms. These tumors may be sporadic or part of any of several genetic diseases: familial pheochromocytoma-paraganglioma syndromes, multiple endocrine neoplasia type 2, neurofibromatosis 1 and von Hippel-Lindau disease. Familial cases are diagnosed earlier and are more frequently bilateral and recurring than sporadic cases. The most specific and sensitive diagnostic test for the tumor is the determination of plasma or urinary metanephrines. The tumor can be located by computed tomography, magnetic resonance imaging and metaiodobenzylguanidine scintigraphy. Treatment requires resection of the tumor, generally by laparoscopic surgery. About 10% of tumors are malignant either at first operation or during follow-up, malignancy being diagnosed by the presence of lymph node, visceral or bone metastases. Recurrences and malignancy are more frequent in cases with large or extraadrenal tumors. Patients, especially those with familial or extraadrenal tumors, should be followed-up indefinitely.

  19. Mechanics

    CERN Document Server

    Hartog, J P Den

    1961-01-01

    First published over 40 years ago, this work has achieved the status of a classic among introductory texts on mechanics. Den Hartog is known for his lively, discursive and often witty presentations of all the fundamental material of both statics and dynamics (and considerable more advanced material) in new, original ways that provide students with insights into mechanical relationships that other books do not always succeed in conveying. On the other hand, the work is so replete with engineering applications and actual design problems that it is as valuable as a reference to the practicing e

  20. [Bone metabolism and cardiovascular function update. α-klotho/FGF23 system; a new insight into the field of mineral homeostasis and the pathogeneses of aging-associated syndromes and the complications of chronic kidney disease].

    Science.gov (United States)

    Nabeshima, Yo Ichi

    2014-07-01

    α-klotho (α-kl) was first identified as an aging gene and was later shown to be a regulator of mineral homeostasis. α-kl (- / -) mice display multiple aging related phenotypes including atherosclerosis, cardiovascular/soft tissue calcifications, pulmonary emphysema, osteopenia, and senile atrophy of skin ; such age-related organ pathologies are associated with biochemical changes in blood, including severe hyperphosphatemia, elevated serum FGF23 and1,25 (OH) 2 Vitamin D levels. Of significance, advanced stage patients suffering chronic kidney disease (CKD) develop multiple complications quite resembling phenotypes observed in α-kl (- / -) mice, and high serum phosphate, the major cause of abnormalities of α-kl (- / -) mice, has been reported to be closely associated with high levels of cardiovascular disease morbidity and mortality in patients with CKD, particularly in patients with end-stage renal disease. In addition, the expressions of α-kl mRNA and α-Kl protein were severely reduced in these patients. These results suggest the involvement of α-Kl and FGF23 in the pathogeneses of not only aging-associated syndromes but also the complications of CKD. Here, the unveiling of the molecular functions of α-Klotho and FGF23 has recently given new insight into the field of mineral homeostasis and the pathogeneses of aging-associated syndromes and the complications of CKD.

  1. 4-Bromophenacyl bromide specifically inhibits rhoptry secretion during Toxoplasma invasion.

    Directory of Open Access Journals (Sweden)

    Sandeep Ravindran

    2009-12-01

    Full Text Available Toxoplasma gondii is a eukaryotic parasite of the phylum Apicomplexa that is able to infect a wide variety of host cells. During its active invasion process it secretes proteins from discrete secretory organelles: the micronemes, rhoptries and dense granules. Although a number of rhoptry proteins have been shown to be involved in important interactions with the host cell, very little is known about the mechanism of secretion of any Toxoplasma protein into the host cell. We used a chemical inhibitor of phospholipase A2s, 4-bromophenacyl bromide (4-BPB, to look at the role of such lipases in the secretion of Toxoplasma proteins. We found that 4-BPB was a potent inhibitor of rhoptry secretion in Toxoplasma invasion. This drug specifically blocked rhoptry secretion but not microneme secretion, thus effectively showing that the two processes can be de-coupled. It affected parasite motility and invasion, but not attachment or egress. Using propargyl- or azido-derivatives of the drug (so-called click chemistry derivatives and a series of 4-BPB-resistant mutants, we found that the drug has a very large number of target proteins in the parasite that are involved in at least two key steps: invasion and intracellular growth. This potent compound, the modified "click-chemistry" forms of it, and the resistant mutants should serve as useful tools to further study the processes of Toxoplasma early invasion, in general, and rhoptry secretion, in particular.

  2. Exosome secretion affects social motility in Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Dror Eliaz

    2017-03-01

    Full Text Available Extracellular vesicles (EV secreted by pathogens function in a variety of biological processes. Here, we demonstrate that in the protozoan parasite Trypanosoma brucei, exosome secretion is induced by stress that affects trans-splicing. Following perturbations in biogenesis of spliced leader RNA, which donates its spliced leader (SL exon to all mRNAs, or after heat-shock, the SL RNA is exported to the cytoplasm and forms distinct granules, which are then secreted by exosomes. The exosomes are formed in multivesicular bodies (MVB utilizing the endosomal sorting complexes required for transport (ESCRT, through a mechanism similar to microRNA secretion in mammalian cells. Silencing of the ESCRT factor, Vps36, compromised exosome secretion but not the secretion of vesicles derived from nanotubes. The exosomes enter recipient trypanosome cells. Time-lapse microscopy demonstrated that cells secreting exosomes or purified intact exosomes affect social motility (SoMo. This study demonstrates that exosomes are delivered to trypanosome cells and can change their migration. Exosomes are used to transmit stress signals for communication between parasites.

  3. Alcohol and gastric acid secretion in humans: a short review.

    Science.gov (United States)

    Singer, M V; Leffmann, C

    1988-01-01

    The action of ethanol and alcoholic beverages on gastric acid secretion and release of gastrin in healthy, nonalcoholic humans is reviewed. Intravenous ethanol causes a dose-dependent stimulation of gastric acid output without releasing gastrin. The action of intragastric instillation of pure ethanol on gastric acid secretion is related to its concentration: concentrations of 1.4% and 4% (v/v) are moderate stimulants; concentrations of 5% to 40% (w/v) have no or rather an inhibitory effect. Oral, intragastric, and intraduodenal administrations of ethanol do not release gastrin, whereas beer and white and red wine but not whisky and cognac are potent stimulants of gastric acid secretion and release gastrin in humans. The stimulatory mechanism of low ethanol concentrations is unknown. Nonalcoholic constituents of beer and wine are most likely responsible for the strong stimulatory action of both beverages on gastric acid secretion and release of gastrin.

  4. [Lacrimal secretion in hormonal imbalance].

    Science.gov (United States)

    Oana, Tălău

    2004-01-01

    The aim of this study is the alteration of lacrimal secretion on a group of female patients with deregulations of the hormonal balance, by the influence of age factor. We have to mention that our female patients have no ocular pathology. The study was conducted on a group of patients aged between 20-70 years old, which has been kept in observation in the Endocrinology Clinic and Obstetrics-Gynecology Clinics of Emergency Hospital, during March-August 2003. Their lacrimal secretion was monitored by volumetric tests (Schirmer). We studied the alteration of the lacrimal secretion on female patients with deregulations of the hormonal balance, by the influence of age factor. It was recorded the alteration of lacrimal secretion on the female patients with aforementioned dysfunction, the age factor being influential.

  5. Secret Public Key Protocols Revisited

    Science.gov (United States)

    Lim, Hoon Wei; Paterson, Kenneth G.

    Password-based protocols are important and popular means of providing human-to-machine authentication. The concept of secret public keys was proposed more than a decade ago as a means of securing password-based authentication protocols against off-line password guessing attacks, but was later found vulnerable to various attacks. In this paper, we revisit the concept and introduce the notion of identity-based secret public keys. Our new identity-based approach allows secret public keys to be constructed in a very natural way using arbitrary random strings, eliminating the structure found in, for example, RSA or ElGamal keys. We examine identity-based secret public key protocols and give informal security analyses, indicating that they are secure against off-line password guessing and other attacks.

  6. Mucin secretion induced by titanium dioxide nanoparticles.

    Directory of Open Access Journals (Sweden)

    Eric Y T Chen

    2011-01-01

    Full Text Available Nanoparticle (NP exposure has been closely associated with the exacerbation and pathophysiology of many respiratory diseases such as Chronic Obstructive Pulmonary Disease (COPD and asthma. Mucus hypersecretion and accumulation in the airway are major clinical manifestations commonly found in these diseases. Among a broad spectrum of NPs, titanium dioxide (TiO(2, one of the PM10 components, is widely utilized in the nanoindustry for manufacturing and processing of various commercial products. Although TiO(2 NPs have been shown to induce cellular nanotoxicity and emphysema-like symptoms, whether TiO(2 NPs can directly induce mucus secretion from airway cells is currently unknown. Herein, we showed that TiO(2 NPs (<75 nm can directly stimulate mucin secretion from human bronchial ChaGo-K1 epithelial cells via a Ca(2+ signaling mediated pathway. The amount of mucin secreted was quantified with enzyme-linked lectin assay (ELLA. The corresponding changes in cytosolic Ca(2+ concentration were monitored with Rhod-2, a fluorescent Ca(2+ dye. We found that TiO(2 NP-evoked mucin secretion was a function of increasing intracellular Ca(2+ concentration resulting from an extracellular Ca(2+ influx via membrane Ca(2+ channels and cytosolic ER Ca(2+ release. The calcium-induced calcium release (CICR mechanism played a major role in further amplifying the intracellular Ca(2+ signal and in sustaining a cytosolic Ca(2+ increase. This study provides a potential mechanistic link between airborne NPs and the pathoetiology of pulmonary diseases involving mucus hypersecretion.

  7. Eosinophil secretion of granule-derived cytokines

    Directory of Open Access Journals (Sweden)

    Lisa A Spencer

    2014-10-01

    Full Text Available Eosinophils are tissue-dwelling leukocytes, present in the thymus, and gastrointestinal and genitourinary tracts of healthy individuals at baseline, and recruited, often in large numbers, to allergic inflammatory foci and sites of active tissue repair. The biological significance of eosinophils is vast and varied. In health, eosinophils support uterine and mammary gland development, and maintain bone marrow plasma cells and adipose tissue alternatively activated macrophages, while in response to tissue insult eosinophils function as inflammatory effector cells, and, in the wake of an inflammatory response, promote tissue regeneration and wound healing. One common mechanism driving many of the diverse eosinophil functions is the regulated and differential secretion of a vast array of eosinophil-derived cytokines. Eosinophils are distinguished from most other leukocytes in that many, if not all, of the over three dozen eosinophil-derived cytokines are pre-synthesized and stored within intracellular granules, poised for very rapid, stimulus-induced secretion. Eosinophils engaged in cytokine secretion in situ utilize distinct pathways of cytokine release that include: classical exocytosis, whereby granules themselves fuse with the plasma membrane and release their entire contents extracellularly; piecemeal degranulation, whereby granule-derived cytokines are selectively mobilized into vesicles that emerge from granules, traverse the cytoplasm and fuse with the plasma membrane to release discrete packets of cytokines; and eosinophil cytolysis, whereby intact granules are extruded from eosinophils, and deposited within tissues. In this latter scenario, extracellular granules can themselves function as stimulus-responsive secretory-competent organelles within the tissue. Here we review the distinctive processes of differential secretion of eosinophil granule-derived cytokines.

  8. Burkholderia cenocepacia type VI secretion system mediates escape of type II secreted proteins into the cytoplasm of infected macrophages.

    Directory of Open Access Journals (Sweden)

    Roberto Rosales-Reyes

    Full Text Available Burkholderia cenocepacia is an opportunistic pathogen that survives intracellularly in macrophages and causes serious respiratory infections in patients with cystic fibrosis. We have previously shown that bacterial survival occurs in bacteria-containing membrane vacuoles (BcCVs resembling arrested autophagosomes. Intracellular bacteria stimulate IL-1β secretion in a caspase-1-dependent manner and induce dramatic changes to the actin cytoskeleton and the assembly of the NADPH oxidase complex onto the BcCV membrane. A Type 6 secretion system (T6SS is required for these phenotypes but surprisingly it is not required for the maturation arrest of the BcCV. Here, we show that macrophages infected with B. cenocepacia employ the NLRP3 inflammasome to induce IL-1β secretion and pyroptosis. Moreover, IL-1β secretion by B. cenocepacia-infected macrophages is suppressed in deletion mutants unable to produce functional Type VI, Type IV, and Type 2 secretion systems (SS. We provide evidence that the T6SS mediates the disruption of the BcCV membrane, which allows the escape of proteins secreted by the T2SS into the macrophage cytoplasm. This was demonstrated by the activity of fusion derivatives of the T2SS-secreted metalloproteases ZmpA and ZmpB with adenylcyclase. Supporting this notion, ZmpA and ZmpB are required for efficient IL-1β secretion in a T6SS dependent manner. ZmpA and ZmpB are also required for the maturation arrest of the BcCVs and bacterial intra-macrophage survival in a T6SS-independent fashion. Our results uncover a novel mechanism for inflammasome activation that involves cooperation between two bacterial secretory pathways, and an unanticipated role for T2SS-secreted proteins in intracellular bacterial survival.

  9. [Alteration of insulin secretion in the elderly].

    Science.gov (United States)

    Aizawa, Toru

    2006-01-01

    Aging per se is associated with reduced insulin secretion, which is an important contributing factor for pandemic of diabetes worldwide. Although underlying mechanism for it is not fully elucidated, a combination of reduced beta cell mass and impairment of insulin granule handing in the cell is most likely which may be due to age-related mitochondrial dysfunction and/or dysregulation of transcriptional factors. For effective prevention of diabetes in the elderly population, restoration of beta cell function is desired. Meanwhile, identification of insulin-deficient elderly patients with diabetes and an earlier institution of insulin therapy for them are recommended for improvement of treatment outcome.

  10. Autophagy Mediates Interleukin-1β Secretion in Human Neutrophils

    Directory of Open Access Journals (Sweden)

    Leonardo Iula

    2018-02-01

    Full Text Available Interleukin-1β (IL-1β, a major pro-inflammatory cytokine, is a leaderless cytosolic protein whose secretion does not follow the classical endoplasmic reticulum-to-Golgi pathway, and for which a canonical mechanism of secretion remains to be established. Neutrophils are essential players against bacterial and fungi infections. These cells are rapidly and massively recruited from the circulation into infected tissues and, beyond of displaying an impressive arsenal of toxic weapons effective to kill pathogens, are also an important source of IL-1β in infectious conditions. Here, we analyzed if an unconventional secretory autophagy mechanism is involved in the exportation of IL-1β by these cells. Our findings indicated that inhibition of autophagy with 3-methyladenine and Wortmannin markedly reduced IL-1β secretion induced by LPS + ATP, as did the disruption of the autophagic flux with Bafilomycin A1 and E64d. These compounds did not noticeable affect neutrophil viability ruling out that the effects on IL-1β secretion were due to cell death. Furthermore, VPS34IN-1, a specific autophagy inhibitor, was still able to reduce IL-1β secretion when added after it was synthesized. Moreover, siRNA-mediated knockdown of ATG5 markedly reduced IL-1β secretion in neutrophil-differentiated PLB985 cells. Upon LPS + ATP stimulation, IL-1β was incorporated to an autophagic compartment, as was revealed by its colocalization with LC3B by confocal microscopy. Overlapping of IL-1β-LC3B in a vesicular compartment peaked before IL-1β increased in culture supernatants. On the other hand, stimulation of autophagy by cell starvation augmented the colocalization of IL-1β and LC3B and then promoted neutrophil IL-1β secretion. In addition, specific ELISAs indicated that although both IL-1β and pro-IL-1β are released to culture supernatants upon neutrophil stimulation, autophagy only promotes IL-1β secretion. Furthermore, the serine proteases inhibitor

  11. Mechanics

    CERN Document Server

    Chester, W

    1979-01-01

    When I began to write this book, I originally had in mind the needs of university students in their first year. May aim was to keep the mathematics simple. No advanced techniques are used and there are no complicated applications. The emphasis is on an understanding of the basic ideas and problems which require expertise but do not contribute to this understanding are not discussed. How­ ever, the presentation is more sophisticated than might be considered appropri­ ate for someone with no previous knowledge of the subject so that, although it is developed from the beginning, some previous acquaintance with the elements of the subject would be an advantage. In addition, some familiarity with element­ ary calculus is assumed but not with the elementary theory of differential equations, although knowledge of the latter would again be an advantage. It is my opinion that mechanics is best introduced through the motion of a particle, with rigid body problems left until the subject is more fully developed. Howev...

  12. Quantum strongly secure ramp secret sharing

    DEFF Research Database (Denmark)

    Zhang, Paul; Matsumoto, Rytaro Yamashita

    2015-01-01

    Quantum secret sharing is a scheme for encoding a quantum state (the secret) into multiple shares and distributing them among several participants. If a sufficient number of shares are put together, then the secret can be fully reconstructed. If an insufficient number of shares are put together...... however, no information about the secret can be revealed. In quantum ramp secret sharing, partial information about the secret is allowed to leak to a set of participants, called an unqualified set, that cannot fully reconstruct the secret. By allowing this, the size of a share can be drastically reduced....... This paper introduces a quantum analog of classical strong security in ramp secret sharing schemes. While the ramp secret sharing scheme still leaks partial information about the secret to unqualified sets of participants, the strong security condition ensures that qudits with critical information can...

  13. QUANTITATIVE STUDIES OF PROSTATIC SECRETION

    Science.gov (United States)

    Huggins, Charles; Masina, M. H.; Eichelberger, Lillian; Wharton, James D.

    1939-01-01

    A simple isolation of the prostate enabled quantitative collection of prostatic secretion in dogs over periods of months. The secretory stimulant was pilocarpine and 2 similar amounts injected with a 6 hour interval gave smaller amounts at the second testing, suggesting a fatigue effect. The prostate was not absolutely refractory since doubling the amount of alkaloid injected at the second test increased the volume to equal or exceed the preliminary secretion. The depression effect had disappeared at 24 hours. In normal dogs the secretory curves were essentially regular, with occasional prolonged rises or depressions. The amount of secretion did not bear a direct relationship to the weight of the gland in adult dogs. The germinal epithelium of the testis underwent atrophy during the first few weeks of cage life while the prostatic secretion was maintained, showing that the atrophy was differential and did not involve the cells producing the androgenic hormone. The atrophy was reversible and all dogs kept for more than 4 months showed restoration of the germ cells. A few dogs developed atrophy of the germinal cells with cessation of prostatic secretion for many weeks but with final recovery. Removal of the suprarenal glands with suprarenal insufficiency did not produce sterility. The distribution of electrolytes in the prostatic secretion differed from that in the serum-transudate system, although the concentration of osmotically active substances was the same, being made up almost entirely of sodium and chloride. The distribution was not affected by the different physiological procedures used in this study. Protein concentrations were less than 1 per cent. The rate of prostatic atrophy following castration was determined, and cessation of secretion occurred in 7 to 23 days. The restoration of prostatic fluid in castrate dogs following daily injections of testosterone propionate followed a smooth curve to form a plateau which was interrupted occasionally by

  14. [Biological rhythms of thyrotropin secretion].

    Science.gov (United States)

    Hugues, J N; Reinberg, A; Lagoguey, M; Modigliani, E; Sebaoun, J

    1983-01-01

    The rhythmic pattern of TSH secretion is now well-established and is characterized by a circadian (24 h) periodicity with a pre-sleep acrophase which is modulated by endogenous oscillators and environmental synchronisers. Among external synchronisers, the sleep-waking cycle has been extensively studied and sleep onset appears to have a negative influence on the nycthemeral TSH peak. Nutritional status may affect the TSH rhythmicity since a short term starvation induces a shift in the acrophase time. Major neurotransmitter involved in the TSH rhythms are serotonine which could be responsible for the TSH nadir. By contrast dopamine is not directly implicated in the circadian pattern of TSH secretion. TRH, the main neuropeptide controlling the thyrotrope cell, certainly has a major role in the mediation of the TSH rhythmicity. The involvement of somatostatine is less clear but as assumed for dopamine, its negative influence on TSH secretion would be stronger at the time of TSH peak than at the time of nadir. The major inhibitory effect of thyroid hormones on TSH secretion and release is evident on mean serum TSH levels but does not seem responsible for serum circadian variations. Likewise, the TSH rhythm is present in both sex and influence of estrogens and androgens would only be to modulate the mean serum TSH level. Finally the physiological influence of glucocorticoids on TSH secretion has not been clearly demonstrated.

  15. Feedback regulation of pancreatic exocrine secretion in minipigs.

    Science.gov (United States)

    Houe, T; Saetre, S S; Svendsen, P; Olsen, O; Rehfeld, J F; Schaffalitzky de Muckadell, O B

    1997-04-01

    The mechanism behind the possible feedback regulation of pancreatic exocrine secretion is not well understood. Thirteen minipigs were prepared with fistulas to the pancreatic duct and the duodenum. Peripheral venous blood was obtained for determination of secretin and cholecystokinin (CCK) levels. Four different experiments were performed: 1) diversion and reinfusion of pancreatic juice; 2) intraduodenal infusion of NaHCO3 solution, with the same volume, bicarbonate concentration, and osmolality as the collected pancreatic secretion, and reinfusion of pancreatic juice; 3) reinfusion of pancreatic secretion for 1 h before and 2 h after a meal; and 4) diversion of pancreatic secretion and intraduodenal infusion of NaHCO33 solutions before and after a meal. Reinfusing pancreatic juice significantly decreased pancreatic juice volume and bicarbonate output and slightly decreased the level of secretin in plasma. Alternating infusions of substitute NaHCO3 and pancreatic juice did not change pancreatic output of bicarbonate and protein, nor did it change the CCK and secretin levels in plasma. Replacing pancreatic juice with intraduodenal NaHCO3 infusions during a meal did not significantly modify the pancreatic secretion of bicarbonate and protein or the hormonal levels in blood. A negative feedback regulation of pancreatic exocrine secretion is present in starved minipigs. Duodenal acidity and plasma levels of secretin semm to be of importance, whereas duodenal enzyme activity and the level of CCK in plasma probably are not. A postprandial negative feedback regulation through duodenal enzymatic activity and release of CCK into blood could not be shown.

  16. Histaminergic regulation of prolactin secretion

    DEFF Research Database (Denmark)

    Knigge, U P

    1990-01-01

    Histamine (HA), which acts as a neurotransmitter in the central nervous system, participates in the neuroendocrine regulation of prolactin (PRL) secretion. HA has a predominant stimulatory effect which is mediated via H2-receptors following central administration and via H1-receptors following...... systemic infusion of the amine. In addition, HA seems to exert a minor inhibitory effect on PRL secretion, an effect unmasked only during blockade of the receptor mediating the stimulatory effect. Following central administration the inhibitory effect is mediated via H1-receptors, while following systemic...... administration this effect is mediated via H2-receptors. In accordance with these findings, the H2-receptor antagonist cimetidine (CIM) has an inhibitory (following central administration) or stimulatory (following systemic administration) effect on PRL secretion. However, high doses of CIM possess an additional...

  17. Impaired Follistatin Secretion in Cirrhosis

    DEFF Research Database (Denmark)

    Rinnov, Anders Rasmussen; Plomgaard, Peter; Pedersen, Bente Klarlund

    2016-01-01

    compared to healthy control participants. DESIGN, SETTING, AND PARTICIPANTS: To experimentally increase the glucagon-insulin ratio (mimicking the hormonal effect of exercise), we infused glucagon/somatostatin (to inhibit insulin secretion) and compared the acute follistatin increase in eight male cirrhosis...... controls (27.6 ± 3.8 vs 34.5 ± 2.9%, respectively; P = .001). CONCLUSIONS: Patients with cirrhosis show impaired capacity to acutely secrete follistatin. The decrease in acute follistatin release may contribute to the loss of muscle mass in liver cirrhosis....

  18. Limiting glucocorticoid secretion increases the anorexigenic property of Exendin-4

    Directory of Open Access Journals (Sweden)

    Shin J. Lee

    2016-07-01

    Conclusions: Our findings demonstrate that limiting glucocorticoid secretion and actions with low dose dexamethasone or DSAP lesion increases Ex-4's ability to reduce food intake and body weight. Novel glucocorticoid receptor based mechanisms, therefore, may help enhance GLP-1-based obesity therapies.

  19. Plant Physiology: The Venus Flytrap Counts on Secretion.

    Science.gov (United States)

    Brownlee, Colin

    2017-08-07

    The Venus flytrap effectively detects, traps, digests and absorbs insect prey. A recent study links the mechanical stimulation of sensory hair cells with short- and long-term signalling giving rise to different downstream secretion events that bring about conditions for prey digestion. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Unraveling the Wnt secretion pathway

    NARCIS (Netherlands)

    Harterink, M.

    2011-01-01

    The Wnt family of signaling proteins has essential functions in development and adult tissue homeostasis throughout the animal kingdom. Although signaling cascades triggered by Wnt proteins have been extensively studied, much remains to be learned about how Wnts are produced and secreted and how

  1. Raspberry Pi for secret agents

    CERN Document Server

    Sjogelid, Stefan

    2015-01-01

    This book is an easy-to-follow guide with practical examples in each chapter. Suitable for the novice and expert alike, each topic provides a fast and easy way to get started with exciting applications and also guides you through setting up the Raspberry Pi as a secret agent toolbox.

  2. FOIA: What's a Trade Secret?

    Science.gov (United States)

    Hawker, Curtis

    The Freedom of Information Act (FOIA) was amended in 1974 in order to restrict government control and to facilitate the public's access to information. However, part of the FOIA bans federal officials from disclosing "trade secrets" and commercial or financial information obtained in confidential circumstances. This exemption has…

  3. Tauroursodeoxycholic acid inserts the apical conjugate export pump, Mrp2, into canalicular membranes and stimulates organic anion secretion by protein kinase C-dependent mechanisms in cholestatic rat liver

    NARCIS (Netherlands)

    Beuers, U.; Bilzer, M.; Chittattu, A.; Kullak-Ublick, G. A.; Keppler, D.; Paumgartner, G.; Dombrowski, F.

    2001-01-01

    Ursodeoxycholic acid (UDCA) exerts anticholestatic effects by undefined mechanisms. Previous work suggested that UDCA stimulates biliary exocytosis via Ca(++)- and protein kinase C (PKC)-dependent mechanisms. Therefore, the effect of taurine-conjugated UDCA (TUDCA) was studied in the experimental

  4. Secretion of a pneumococcal type II secretion system pilus correlates with DNA uptake during transformation.

    Science.gov (United States)

    Balaban, Murat; Bättig, Patrick; Muschiol, Sandra; Tirier, Stephan M; Wartha, Florian; Normark, Staffan; Henriques-Normark, Birgitta

    2014-02-18

    Streptococcus pneumoniae is a major human pathogen that successfully adapts to the host environment via an efficient uptake system for free DNA liberated from other organisms in the upper respiratory tract, facilitating immune evasion and drug resistance. Although the initial signaling events leading to pneumococcal competence for DNA transformation and the fate of DNA when it has been taken up have been extensively studied, the actual mechanism by which DNA in the environment may traverse the thick capsular and cell wall layers remains unknown. Here we visualize that induction of competence results in the formation of a native morphologically distinct pilus structure on the bacterial surface. This plaited pilus is encoded by the competence (com)G locus, and, after assembly, it is rapidly released into the surrounding medium. Heterologous pneumococcal pilus expression in Escherichia coli was obtained by replacing the pulE-K putative pilin genes of the Klebsiella oxytoca type II secretion system with the complete comG locus. In the pneumococcus, the coordinated secretion of pili from the cells correlates to DNA transformation. A model for DNA transformation is proposed whereby pilus assembly "drills" a channel across the thick cell wall that becomes transiently open by secretion of the pilus, providing the entry port for exogenous DNA to gain access to DNA receptors associated with the cytoplasmic membrane.

  5. Tamper-proof secret image-sharing scheme for identifying cheated secret keys and shared images

    Science.gov (United States)

    Chen, Chien-Chang; Liu, Chong-An

    2013-01-01

    A (t,n) secret image-sharing scheme shares a secret image to n participants, and the t users recover the image. During the recovery procedure of a conventional secret image-sharing scheme, cheaters may use counterfeit secret keys or modified shared images to cheat other users' secret keys and shared images. A cheated secret key or shared image leads to an incorrect secret image. Unfortunately, the cheater cannot be identified. We present an exponent and modulus-based scheme to provide a tamper-proof secret image-sharing scheme for identifying cheaters on secret keys or shared images. The proposed scheme allows users to securely select their secret key. This assignment can be performed over networks. Modulus results of each shared image is calculated to recognize cheaters of a shared image. Experimental results indicate that the proposed scheme is excellent at identifying cheated secret keys and shared images.

  6. Fibroblast growth factor 21, fibroblast growth factor receptor 1, and β-Klotho expression in bovine growth hormone transgenic and growth hormone receptor knockout mice.

    Science.gov (United States)

    Brooks, Nicole E; Hjortebjerg, Rikke; Henry, Brooke E; List, Edward O; Kopchick, John J; Berryman, Darlene E

    Although growth hormone (GH) and fibroblast growth factor 21 (FGF21) have a reported relationship, FGF21 and its receptor, fibroblast growth factor receptor 1 (FGFR1) and cofactor β-Klotho (KLB), have not been analyzed in chronic states of altered GH action. The objective of this study was to quantify circulating FGF21 and tissue specific expression of Fgf21, Fgfr1, and Klb in mice with modified GH action. Based on previous studies, we hypothesized that bovine GH transgenic (bGH) mice will be FGF21 resistant and GH receptor knockout (GHR-/-) mice will have normal FGF21 action. Seven-month-old male bGH mice (n=9) and wild type (WT) controls (n=10), and GHR-/- mice (n=8) and WT controls (n=8) were used for all measurements. Body composition was determined before dissection, and tissue weights were measured at the time of dissection. Serum FGF21 levels were evaluated by ELISA. Expression of Fgf21, Fgfr1, and Klb mRNA in white adipose tissue (AT), brown AT, and liver were evaluated by reverse transcription quantitative PCR. As expected, bGH mice had increased body weight (p=3.70E -8 ) but decreased percent fat mass (p=4.87E -4 ). Likewise, GHR-/- mice had decreased body weight (p=1.78E -10 ) but increased percent fat mass (p=1.52E -9 ), due to increased size of the subcutaneous AT depot when normalized to body weight (p=1.60E -10 ). Serum FGF21 levels were significantly elevated in bGH mice (p=0.041) and unchanged in GHR-/- mice (p=0.88). Expression of Fgf21, Fgfr1, and Klb mRNA in white AT and liver were downregulated or unchanged in both bGH and GHR-/- mice. The only exception was Fgf21 expression in brown AT of GHR-/-, which trended toward increased expression (p=0.075). In accordance with our hypothesis, we provide evidence that circulating FGF21 is increased in bGH animals, but remains unchanged in GHR-/- mice. Downregulation or no change in Fgf21, Fgfr1, and Klb expression are seen in white AT, brown AT, and liver of bGH and GHR-/- mice when compared to their

  7. Prelysosomal Compartments in the Unconventional Secretion of Amyloidogenic Seeds

    DEFF Research Database (Denmark)

    Borland, Helena; Vilhardt, Frederik

    2017-01-01

    , mainly for Parkinson's disease. Exocytosis of prelysosomal or lysosomal organelles is a last resort for clearance of cytotoxic material and alleviates cytopathy. However, they also represent a vehicle for the concentration, posttranslational modification, and secretion of amyloid seeds.......A mechanistic link between neuron-to-neuron transmission of secreted amyloid and propagation of protein malconformation cytopathology and disease has recently been uncovered in animal models. An enormous interest in the unconventional secretion of amyloids from neurons has followed. Amphisomes....... The ESCRT-mediated import of cytosolic amyloid into late endosomal exosomes, a known vehicle of transmission of macromolecules between cells, is also reviewed. Finally, mechanisms of lysosomal dysfunction, deficiency, and exocytosis are exemplified in the context of genetically identified risk factors...

  8. Incretins, insulin secretion and Type 2 diabetes mellitus

    DEFF Research Database (Denmark)

    Vilsbøll, T; Holst, Jens Juul

    2004-01-01

    the genes encoding their receptors have been deleted. In patients with Type 2 diabetes, the incretin effect is either greatly impaired or absent, and it is assumed that this could contribute to the inability of these patients to adjust their insulin secretion to their needs. In studies of the mechanism...... of the impaired incretin effect in Type 2 diabetic patients, it has been found that the secretion of GIP is generally normal, whereas the secretion of GLP-1 is reduced, presumably as a consequence of the diabetic state. It might be of even greater importance that the effect of GLP-1 is preserved whereas...... the effect of GIP is severely impaired. The impaired GIP effect seems to have a genetic background, but could be aggravated by the diabetic state. The preserved effect of GLP-1 has inspired attempts to treat Type 2 diabetes with GLP-1 or analogues thereof, and intravenous GLP-1 administration has been shown...

  9. Peroxicretion: a novel secretion pathway in the eukaryotic cell

    Directory of Open Access Journals (Sweden)

    Luesken Francisca A

    2009-05-01

    Full Text Available Abstract Background Enzyme production in microbial cells has been limited to secreted enzymes or intracellular enzymes followed by expensive down stream processing. Extracellular enzymes consists mainly of hydrolases while intracellular enzymes exhibit a much broader diversity. If these intracellular enzymes could be secreted by the cell the potential of industrial applications of enzymes would be enlarged. Therefore a novel secretion pathway for intracellular proteins was developed, using peroxisomes as secretion vesicles. Results Peroxisomes were decorated with a Golgi derived v-SNARE using a peroxisomal membrane protein as an anchor. This allowed the peroxisomes to fuse with the plasma membrane. Intracellular proteins were transported into the peroxisomes by adding a peroxisomal import signal (SKL tag. The proteins which were imported in the peroxisomes, were released into the extra-cellular space through this artificial secretion pathway which was designated peroxicretion. This concept was supported by electron microscopy studies. Conclusion Our results demonstrate that it is possible to reroute the intracellular trafficking of vesicles by changing the localisation of SNARE molecules, this approach can be used in in vivo biological studies to clarify the different control mechanisms regulating intracellular membrane trafficking. In addition we demonstrate peroxicretion of a diverse set of intracellular proteins. Therefore, we anticipate that the concept of peroxicretion may revolutionize the production of intracellular proteins from fungi and other microbial cells, as well as from mammalian cells.

  10. 29 CFR 1903.9 - Trade secrets.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 5 2010-07-01 2010-07-01 false Trade secrets. 1903.9 Section 1903.9 Labor Regulations... INSPECTIONS, CITATIONS AND PROPOSED PENALTIES § 1903.9 Trade secrets. (a) Section 15 of the Act provides: “All... inspection or proceeding under this Act which contains or which might reveal a trade secret referred to in...

  11. Some Economics of Trade Secret Law

    OpenAIRE

    David D. Friedman; William M. Landes; Richard A. Posner

    1991-01-01

    Despite the practical importance of trade secrets to the business community, the law of trade secrets is a neglected orphan in economic analysis. This paper sketches an approach to the economics of trade secret law that connects it more closely both to other areas of intellectual property and to broader issues in the positive economic theory of the common law.

  12. Transporter-mediated biofuel secretion.

    Science.gov (United States)

    Doshi, Rupak; Nguyen, Tuan; Chang, Geoffrey

    2013-05-07

    Engineering microorganisms to produce biofuels is currently among the most promising strategies in renewable energy. However, harvesting these organisms for extracting biofuels is energy- and cost-intensive, limiting the commercial feasibility of large-scale production. Here, we demonstrate the use of a class of transport proteins of pharmacological interest to circumvent the need to harvest biomass during biofuel production. We show that membrane-embedded transporters, better known to efflux lipids and drugs, can be used to mediate the secretion of intracellularly synthesized model isoprenoid biofuel compounds to the extracellular milieu. Transporter-mediated biofuel secretion sustainably maintained an approximate three- to fivefold boost in biofuel production in our Escherichia coli test system. Because the transporters used in this study belong to the ubiquitous ATP-binding cassette protein family, we propose their use as "plug-and-play" biofuel-secreting systems in a variety of bacteria, cyanobacteria, diatoms, yeast, and algae used for biofuel production. This investigation showcases the potential of expressing desired membrane transport proteins in cell factories to achieve the export or import of substances of economic, environmental, or therapeutic importance.

  13. Type VI Secretion Effectors: Methodologies and Biology

    Directory of Open Access Journals (Sweden)

    Yun-Wei Lien

    2017-06-01

    Full Text Available The type VI secretion system (T6SS is a nanomachine deployed by many Gram-negative bacteria as a weapon against eukaryotic hosts or prokaryotic competitors. It assembles into a bacteriophage tail-like structure that can transport effector proteins into the environment or target cells for competitive survival or pathogenesis. T6SS effectors have been identified by a variety of approaches, including knowledge/hypothesis-dependent and discovery-driven approaches. Here, we review and discuss the methods that have been used to identify T6SS effectors and the biological and biochemical functions of known effectors. On the basis of the nature and transport mechanisms of T6SS effectors, we further propose potential strategies that may be applicable to identify new T6SS effectors.

  14. Reduced ghrelin secretion in the hypothalamus of rats due to cisplatin-induced anorexia.

    Science.gov (United States)

    Yakabi, Koji; Sadakane, Chiharu; Noguchi, Masamichi; Ohno, Shino; Ro, Shoki; Chinen, Katsuya; Aoyama, Toru; Sakurada, Tomoya; Takabayashi, Hideaki; Hattori, Tomohisa

    2010-08-01

    Although chemotherapy with cisplatin is a widely used and effective cancer treatment, the undesirable gastrointestinal side effects associated with it, such as nausea, vomiting, and anorexia, markedly decrease patients' quality of life. To elucidate the mechanism underlying chemotherapy-induced anorexia, focusing on the hypothalamic ghrelin secretion-anorexia association, we measured hypothalamic ghrelin secretion in fasted and cisplatin-treated rats. Hypothalamic ghrelin secretion changes after vagotomy or administration of cisplatin. Cisplatin + rikkunshito, a serotonin 2C receptor antagonist or serotonin 3 receptor antagonist, was investigated. The effects of intracerebroventricular (icv) administration of ghrelin or the serotonin 2C receptor antagonist SB242084 on food intake were also evaluated in cisplatin-treated rats. Hypothalamic ghrelin secretion significantly increased in 24-h-fasted rats compared to freely fed rats and was markedly reduced 24 and 48 h after cisplatin treatment in cisplatin-treated rats compared to saline-treated rats, although their plasma ghrelin levels were comparable. In cisplatin-treated rats, icv ghrelin administration reversed the decrease in food intake, vagotomy partially restored hypothalamic ghrelin secretion, and hypothalamic serotonin 2C receptor mRNA expression increased significantly. Administration of rikkunshito (an endogenous ghrelin enhancer) or a serotonin 2C receptor antagonist reversed the decrease in hypothalamic ghrelin secretion and food intake 24 h after cisplatin treatment. Cisplatin-induced anorexia is mediated through reduced hypothalamic ghrelin secretion. Cerebral serotonin 2C receptor activation partially induces decrease in hypothalamic ghrelin secretion, and rikkunshito suppresses cisplatin-induced anorexia by enhancing this secretion.

  15. Proteomic Identification of Novel Secreted Antibacterial Toxins of the Serratia marcescens Type VI Secretion System*

    Science.gov (United States)

    Fritsch, Maximilian J.; Trunk, Katharina; Diniz, Juliana Alcoforado; Guo, Manman; Trost, Matthias; Coulthurst, Sarah J.

    2013-01-01

    It has recently become apparent that the Type VI secretion system (T6SS) is a complex macromolecular machine used by many bacterial species to inject effector proteins into eukaryotic or bacterial cells, with significant implications for virulence and interbacterial competition. “Antibacterial” T6SSs, such as the one elaborated by the opportunistic human pathogen, Serratia marcescens, confer on the secreting bacterium the ability to rapidly and efficiently kill rival bacteria. Identification of secreted substrates of the T6SS is critical to understanding its role and ability to kill other cells, but only a limited number of effectors have been reported so far. Here we report the successful use of label-free quantitative mass spectrometry to identify at least eleven substrates of the S. marcescens T6SS, including four novel effector proteins which are distinct from other T6SS-secreted proteins reported to date. These new effectors were confirmed as antibacterial toxins and self-protecting immunity proteins able to neutralize their cognate toxins were identified. The global secretomic study also unexpectedly revealed that protein phosphorylation-based post-translational regulation of the S. marcescens T6SS differs from that of the paradigm, H1-T6SS of Pseudomonas aeruginosa. Combined phosphoproteomic and genetic analyses demonstrated that conserved PpkA-dependent threonine phosphorylation of the T6SS structural component Fha is required for T6SS activation in S. marcescens and that the phosphatase PppA can reverse this modification. However, the signal and mechanism of PpkA activation is distinct from that observed previously and does not appear to require cell–cell contact. Hence this study has not only demonstrated that new and species-specific portfolios of antibacterial effectors are secreted by the T6SS, but also shown for the first time that PpkA-dependent post-translational regulation of the T6SS is tailored to fit the needs of different bacterial

  16. LcrG secretion is not required for blocking of Yops secretion in Yersinia pestis

    Directory of Open Access Journals (Sweden)

    Matson Jyl S

    2008-02-01

    Full Text Available Abstract Background LcrG, a negative regulator of the Yersinia type III secretion apparatus has been shown to be primarily a cytoplasmic protein, but is secreted at least in Y. pestis. LcrG secretion has not been functionally analyzed and the relevance of LcrG secretion on LcrG function is unknown. Results An LcrG-GAL4AD chimera, originally constructed for two-hybrid analyses to analyze LcrG protein interactions, appeared to be not secreted but the LcrG-GAL4AD chimera retained the ability to regulate Yops secretion. This result led to further investigation to determine the significance of LcrG secretion on LcrG function. Additional analyses including deletion and substitution mutations of amino acids 2–6 in the N-terminus of LcrG were constructed to analyze LcrG secretion and LcrG's ability to control secretion. Some changes to the N-terminus of LcrG were found to not affect LcrG's secretion or LcrG's secretion-controlling activity. However, substitution of poly-isoleucine in the N-terminus of LcrG did eliminate LcrG secretion but did not affect LcrG's secretion controlling activity. Conclusion These results indicate that secretion of LcrG, while observable and T3SS mediated, is not relevant for LcrG's ability to control secretion.

  17. Weegee’s City Secrets

    Directory of Open Access Journals (Sweden)

    Alan TRACHTENBERG

    2010-03-01

    Full Text Available En tant que photographe indépendant de meurtres, d’accidents, d’incendies, mais aussi de moments de loisirs dans la ville — de scènes de violence et de plaisir — Weegee travaillait essentiellement la nuit et utilisait un flash puissant associé à son appareil-photo de presse. Ses « secrets pour réaliser des photographies avec un flash » consistent à donner des conseils pratiques et techniques pour débutants. Mais au cœur de la rhétorique de ses « secrets » se trouvent des réflexions subtiles et convaincantes révélant la relation entre la lumière et l’obscurité, et plus particulièrement la manière dont la lumière du flash permet de rendre visible l’obscurité. Dans le récit de Weegee, le flash confère à la photographie le pouvoir d’écrire — d’écrire avec la lumière, un mode de représentation singulièrement approprié pour enregistrer des instants de vie dans les rues nocturnes de la ville.As a freelance photographer of crime, accidents, fires, and also of the recreational life of the city—scenes of violence and of pleasure—Weegee worked mainly at night and employed a powerful photoflash attachment to his press camera. His "secrets of shooting with photoflash" consist of practical technical advice for beginners. But within the rhetoric of his "secrets" there lie cogent and subtle reflections on the relation of light to darkness, especially on the way the flash of light makes darkness visible. In Weegee’s account, the photoflash gives photography the power of writing—writing with light, a mode of picturing uniquely suited to recording instants of life on city streets at night.

  18. Native Small Airways Secrete Bicarbonate

    OpenAIRE

    Shamsuddin, A. K. M.; Quinton, Paul M.

    2014-01-01

    Since the discovery of Cl− impermeability in cystic fibrosis (CF) and the cloning of the responsible channel, CF pathology has been widely attributed to a defect in epithelial Cl− transport. However, loss of bicarbonate (HCO3−) transport also plays a major, possibly more critical role in CF pathogenesis. Even though HCO3− transport is severely affected in the native pancreas, liver, and intestines in CF, we know very little about HCO3− secretion in small airways, the principle site of morbidi...

  19. How to Share Secret Efficiently over Networks

    Directory of Open Access Journals (Sweden)

    Lein Harn

    2017-01-01

    Full Text Available In a secret-sharing scheme, the secret is shared among a set of shareholders, and it can be reconstructed if a quorum of these shareholders work together by releasing their secret shares. However, in many applications, it is undesirable for nonshareholders to learn the secret. In these cases, pairwise secure channels are needed among shareholders to exchange the shares. In other words, a shared key needs to be established between every pair of shareholders. But employing an additional key establishment protocol may make the secret-sharing schemes significantly more complicated. To solve this problem, we introduce a new type of secret-sharing, called protected secret-sharing (PSS, in which the shares possessed by shareholders not only can be used to reconstruct the original secret but also can be used to establish the shared keys between every pair of shareholders. Therefore, in the secret reconstruction phase, the recovered secret is only available to shareholders but not to nonshareholders. In this paper, an information theoretically secure PSS scheme is proposed, its security properties are analyzed, and its computational complexity is evaluated. Moreover, our proposed PSS scheme also can be applied to threshold cryptosystems to prevent nonshareholders from learning the output of the protocols.

  20. Glucotoxicity induces abnormal glucagon secretion through impaired insulin signaling in InR1G cells.

    Directory of Open Access Journals (Sweden)

    Takashi Katsura

    Full Text Available The significance of glucagon in the pathophysiology of diabetes mellitus is widely recognized, but the mechanisms underlying dysregulated glucagon secretion are still unclear. Here, we explored the molecular mechanisms of glucagon dysregulation, using an in vitro model. Hamster-derived glucagon-secreting InR1G cells were exposed to high glucose (25 mM levels for 12 h before analyzing glucagon secretion and the activity of components involved in insulin signaling. High-glucose treatment induced increased glucagon secretion in InR1G cells, which represents a hallmark of diabetes mellitus. This treatment reduced the phosphorylation of Akt, indicating the deterioration of insulin signaling. Simultaneously, oxidative stress and JNK activity were shown to be increased. The inhibition of JNK signaling resulted in the amelioration of high-glucose level-induced glucagon secretion. Abnormally elevated glucagon secretion in diabetes can be reproduced by high-glucose treatment of InR1G cells, and the involvement of high glucose-oxidative stress-JNK-insulin signaling pathway axis has been demonstrated. These data elucidate, at least partly, the previously unclear mechanism of abnormal glucagon secretion, providing insights into a potential novel approach to diabetes treatment, targeting glucagon.

  1. Accurate prediction of secreted substrates and identification of a conserved putative secretion signal for type III secretion systems.

    Directory of Open Access Journals (Sweden)

    Ram Samudrala

    2009-04-01

    Full Text Available The type III secretion system is an essential component for virulence in many Gram-negative bacteria. Though components of the secretion system apparatus are conserved, its substrates--effector proteins--are not. We have used a novel computational approach to confidently identify new secreted effectors by integrating protein sequence-based features, including evolutionary measures such as the pattern of homologs in a range of other organisms, G+C content, amino acid composition, and the N-terminal 30 residues of the protein sequence. The method was trained on known effectors from the plant pathogen Pseudomonas syringae and validated on a set of effectors from the animal pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium after eliminating effectors with detectable sequence similarity. We show that this approach can predict known secreted effectors with high specificity and sensitivity. Furthermore, by considering a large set of effectors from multiple organisms, we computationally identify a common putative secretion signal in the N-terminal 20 residues of secreted effectors. This signal can be used to discriminate 46 out of 68 total known effectors from both organisms, suggesting that it is a real, shared signal applicable to many type III secreted effectors. We use the method to make novel predictions of secreted effectors in S. Typhimurium, some of which have been experimentally validated. We also apply the method to predict secreted effectors in the genetically intractable human pathogen Chlamydia trachomatis, identifying the majority of known secreted proteins in addition to providing a number of novel predictions. This approach provides a new way to identify secreted effectors in a broad range of pathogenic bacteria for further experimental characterization and provides insight into the nature of the type III secretion signal.

  2. Alterations of male sexual behavior by learned aversions to hamster vaginal secretion.

    Science.gov (United States)

    Johnston, R E; Zahorik, D M; Immler, K; Zakon, H

    1978-02-01

    Male hamsters poisoned after their first adult exposure to the vaginal secretion of female hamsters became hesitant to approach and ingest the secretion. The same aversion-training procedure also altered the responses of males to estrous females, changing the latency, frequency, and duration of a variety of behaviors that are commonly taken as indexes of sexual attraction or arousal and of copulatory performance. The effects suggest that the aversions to vaginal secretion alter the perceived meaning of the secretion for male hamsters, and analysis of the correlations between various measures of sexual arousal and performance support the hypothesis that separate mechanisms underlie the effects of the secretion on appetitive and consummatory sexual behavior.

  3. Insulin-degrading enzyme is exported via an unconventional protein secretion pathway

    Directory of Open Access Journals (Sweden)

    Leissring Malcolm A

    2009-01-01

    Full Text Available Abstract Insulin-degrading enzyme (IDE is a ubiquitously expressed zinc-metalloprotease that degrades several pathophysiologically significant extracellular substrates, including insulin and the amyloid β-protein (Aβ, and accumulating evidence suggests that IDE dysfunction may be operative in both type 2 diabetes mellitus and Alzheimer disease (AD. Although IDE is well known to be secreted by a variety of cell types, the underlying trafficking pathway(s remain poorly understood. To address this topic, we investigated the effects of known inhibitors or stimulators of protein secretion on the secretion of IDE from murine hepatocytes and HeLa cells. IDE secretion was found to be unaffected by the classical secretion inhibitors brefeldin A (BFA, monensin, or nocodazole, treatments that readily inhibited the secretion of α1-antitrypsin (AAT overexpressed in the same cells. Using a novel cell-based Aβ-degradation assay, we show further that IDE secretion was similarly unaffected by multiple stimulators of protein secretion, including glyburide and 3'-O-(4-benzoylbenzoyl-ATP (Bz-ATP. The calcium ionophore, A23187, increased extracellular IDE activity, but only under conditions that also elicited cytotoxicity. Our results provide the first biochemical evidence that IDE export is not dependent upon the classical secretion pathway, thereby identifying IDE as a novel member of the select class of unconventionally secreted proteins. Further elucidation of the mechanisms underlying IDE secretion, which would be facilitated by the assays described herein, promises to uncover processes that might be defective in disease or manipulated for therapeutic benefit.

  4. Secret Sharing Schemes and Advanced Encryption Standard

    Science.gov (United States)

    2015-09-01

    Secret Sharing Scheme, they have only been better under certain parameters; there is always a trade -off with some parameter of the scheme. xiv...NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS SECRET SHARING SCHEMES AND ADVANCED ENCRYPTION STANDARD by Bing Yong Lim September 2015 Thesis...AND SUBTITLE SECRET SHARING SCHEMES AND ADVANCED ENCRYPTION STANDARD 5. FUNDING NUMBERS 6. AUTHOR(S) Lim, Bin Yong 7. PERFORMING ORGANIZATION NAME(S

  5. Secreted HSP Vaccine for Malaria Prophylaxis

    Science.gov (United States)

    2017-10-01

    AWARD NUMBER: W81XWH-13-2-0098 TITLE: Secreted HSP Vaccine for Malaria Prophylaxis PRINCIPAL INVESTIGATOR: Natasa Strbo CONTRACTING...1. REPORT DATE October 2017 2. REPORT TYPE Annual 3. DATES COVERED 09/30/16-09/29/17 4. TITLE AND SUBTITLE Secreted HSP Vaccine for Malaria...thereby stimulating an avid, antigen specific, cytotoxic CD8 T cell response. Here we developed malaria vaccine that relies on secreted gp96-Ig

  6. Salamanders on the bench - A biocompatibility study of salamander skin secretions in cell cultures.

    Science.gov (United States)

    von Byern, Janek; Mebs, Dietrich; Heiss, Egon; Dicke, Ursula; Wetjen, Oliver; Bakkegard, Kristin; Grunwald, Ingo; Wolbank, Susanne; Mühleder, Severin; Gugerell, Alfred; Fuchs, Heidemarie; Nürnberger, Sylvia

    2017-09-01

    Salamanders have evolved a wide variety of antipredator mechanisms and behavior patterns, including toxins and noxious or adhesive skin secretions. The high bonding strength of the natural bioadhesives makes these substances interesting for biomimetic research and applications in industrial and medical sectors. Secretions of toxic species may help to understand the direct effect of harmful substances on the cellular level. In the present study, the biocompatibility of adhesive secretions from four salamander species (Plethodon shermani, Plethodon glutinosus, Ambystoma maculatum, Ambystoma opacum) were analyzed using the MTT assay in cell culture and evaluated against toxic secretions of Pleurodeles waltl, Triturus carnifex, Pseudotriton ruber, Tylototriton verrucosus, and Salamandra salamandra. Their effect on cells was tested in direct contact (direct culture) or under the influence of the extract (indirect exposure) in accordance with the protocol of the international standard norm ISO 10993-5. Human dermal fibroblasts (NHDF), umbilical vein endothelial cells (HUVEC), and articular chondrocytes (HAC), as well as the cell lines C2C12 and L929 were used in both culture types. While the adhesive secretions from Plethodon shermani are cytocompatible and those of Ambystoma opacum are even advantageous, those of Plethodon glutinosus and Ambystoma maculatum appear to be cytotoxic to NDHF and HUVEC. Toxic secretions from Salamandra salamandra exhibited harmful effects on all cell types. Pseudotriton ruber and Triturus carnifex secretions affected certain cell types marginally; those from Pleurodeles waltl and Tylototriton verrucosus were generally well tolerated. The study shows for the first time the effect of salamander secretions on the viability of different cell types in culture. Two adhesive secretions appeared to be cell compatible and are therefore promising candidates for future investigations in the field of medical bioadhesives. Among the toxic secretions

  7. Pulsatile insulin secretion, impaired glucose tolerance and type 2 diabetes.

    Science.gov (United States)

    Satin, Leslie S; Butler, Peter C; Ha, Joon; Sherman, Arthur S

    2015-04-01

    Type 2 diabetes (T2DM) results when increases in beta cell function and/or mass cannot compensate for rising insulin resistance. Numerous studies have documented the longitudinal changes in metabolism that occur during the development of glucose intolerance and lead to T2DM. However, the role of changes in insulin secretion, both amount and temporal pattern, has been understudied. Most of the insulin secreted from pancreatic beta cells of the pancreas is released in a pulsatile pattern, which is disrupted in T2DM. Here we review the evidence that changes in beta cell pulsatility occur during the progression from glucose intolerance to T2DM in humans, and contribute significantly to the etiology of the disease. We review the evidence that insulin pulsatility improves the efficacy of secreted insulin on its targets, particularly hepatic glucose production, but also examine evidence that pulsatility alters or is altered by changes in peripheral glucose uptake. Finally, we summarize our current understanding of the biophysical mechanisms responsible for oscillatory insulin secretion. Understanding how insulin pulsatility contributes to normal glucose homeostasis and is altered in metabolic disease states may help improve the treatment of T2DM. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Pulsatile insulin secretion, impaired glucose tolerance and type 2 diabetes

    Science.gov (United States)

    Satin, Leslie S.; Butler, Peter C.; Ha, Joon; Sherman, Arthur S.

    2015-01-01

    Type 2 diabetes (T2DM) results when increases in beta cell function and/or mass cannot compensate for rising insulin resistance. Numerous studies have documented the longitudinal changes in metabolism that occur during the development of glucose intolerance and lead to T2DM. However, the role of changes in insulin secretion, both amount and temporal pattern has been understudied. Most of the insulin secreted from pancreatic beta cells of the pancreas is released in a pulsatile pattern, which is disrupted in T2DM. Here we review the evidence that changes in beta cell pulsatility occur during the progression from glucose intolerance to T2DM in humans, and contribute significantly to the etiology of the disease. We review the evidence that insulin pulsatility improves the efficacy of secreted insulin on its targets, particularly hepatic glucose production, but also examine evidence that pulsatility alters or is altered by changes in peripheral glucose uptake. Finally, we summarize our current understanding of the biophysical mechanisms responsible for oscillatory insulin secretion. Understanding how insulin pulsatility contributes to normal glucose homeostasis and is altered in metabolic disease states may help improve the treatment of T2DM. PMID:25637831

  9. Prelysosomal Compartments in the Unconventional Secretion of Amyloidogenic Seeds

    Directory of Open Access Journals (Sweden)

    Helena Borland

    2017-01-01

    Full Text Available A mechanistic link between neuron-to-neuron transmission of secreted amyloid and propagation of protein malconformation cytopathology and disease has recently been uncovered in animal models. An enormous interest in the unconventional secretion of amyloids from neurons has followed. Amphisomes and late endosomes are the penultimate maturation products of the autophagosomal and endosomal pathways, respectively, and normally fuse with lysosomes for degradation. However, under conditions of perturbed membrane trafficking and/or lysosomal deficiency, prelysosomal compartments may instead fuse with the plasma membrane to release any contained amyloid. After a brief introduction to the endosomal and autophagosomal pathways, we discuss the evidence for autophagosomal secretion (exophagy of amyloids, with a comparative emphasis on Aβ1–42 and α-synuclein, as luminal and cytosolic amyloids, respectively. The ESCRT-mediated import of cytosolic amyloid into late endosomal exosomes, a known vehicle of transmission of macromolecules between cells, is also reviewed. Finally, mechanisms of lysosomal dysfunction, deficiency, and exocytosis are exemplified in the context of genetically identified risk factors, mainly for Parkinson’s disease. Exocytosis of prelysosomal or lysosomal organelles is a last resort for clearance of cytotoxic material and alleviates cytopathy. However, they also represent a vehicle for the concentration, posttranslational modification, and secretion of amyloid seeds.

  10. Current Therapies That Modify Glucagon Secretion

    DEFF Research Database (Denmark)

    Grøndahl, Magnus F.; Keating, Damien J.; Vilsbøll, Tina

    2017-01-01

    and provide insights into how antidiabetic drugs influence glucagon secretion as well as a perspective on the future of glucagon-targeting drugs. Recent Findings: Several older as well as recent investigations have evaluated the effect of antidiabetic agents on glucagon secretion to understand how glucagon...... of altering glucagon secretion: metformin, sulfonylurea compounds, insulin, glucagon-like peptide-1 receptor agonists, dipeptidyl peptidase-4 inhibitors, sodium-glucose cotransporter 2 inhibitors and amylin mimetics. Their diverse effects on glucagon secretion are of importance for their individual efficacy...

  11. Comparing Security Notions of Secret Sharing Schemes

    Directory of Open Access Journals (Sweden)

    Songsong Dai

    2015-03-01

    Full Text Available Different security notions of secret sharing schemes have been proposed by different information measures. Entropies, such as Shannon entropy and min entropy, are frequently used in the setting security notions for secret sharing schemes. Different to the entropies, Kolmogorov complexity was also defined and used in study the security of individual instances for secret sharing schemes. This paper is concerned with these security notions for secret sharing schemes defined by the variational measures, including Shannon entropy, guessing probability, min entropy and Kolmogorov complexity.

  12. Thymidine secretion by hybridoma and myeloma cells

    International Nuclear Information System (INIS)

    Spilsberg, Bjorn; Rise, Frode; Petersen, Dirk; Nissen-Meyer, Jon

    2006-01-01

    Secretion of thymidine appeared to be a common property of hybridoma and myeloma cells, but not of other cell types, which were tested. Of three hybridoma cell lines tested, all secreted thymidine in amounts resulting in the accumulation of thymidine to concentrations of 10-20 μM in the culture medium. Also three of five myeloma cell lines that were analyzed secrete thymidine, but none of the other cell types that were studied. Thymidine was purified to homogeneity (4 mg purified from 3 l of culture medium) and identified as such by nuclear magnetic resonance spectroscopy. The cells that secreted thymidine showed high resistance to the growth inhibitory effect of thymidine

  13. Overexpressing key component genes of the secretion pathway for enhanced secretion of an Aspergillus niger glucose oxidase in Trichoderma reesei.

    Science.gov (United States)

    Wu, Yilan; Sun, Xianhua; Xue, Xianli; Luo, Huiying; Yao, Bin; Xie, Xiangming; Su, Xiaoyun

    2017-11-01

    Vast interest exists in developing T. reesei for production of heterologous proteins. Although rich genomic and transcriptomic information has been uncovered for the T. reesei secretion pathway, little is known about whether engineering its key components could enhance expression of a heterologous gene. In this study, snc1, a v-SNARE gene, was first selected for overexpression in T. reesei. In engineered T. reesei with additional copies of snc1, the Aspergillus niger glucose oxidase (AnGOD) was produced to a significantly higher level (2.2-fold of the parental strain). hac1 and bip1, two more component genes in the secretion pathway, were further tested for overexpression and found to be also beneficial for AnGOD secretion. The overexpression of one component gene more or less affected the expression of the other two genes, suggesting a complex regulating mechanism. Our study demonstrates the potential of engineering the secretion pathway for enhancing heterologous gene production in T. reesei. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. The Chlamydia type III secretion system C-ring engages a chaperone-effector protein complex.

    Directory of Open Access Journals (Sweden)

    Kris E Spaeth

    2009-09-01

    Full Text Available In Gram-negative bacterial pathogens, specialized chaperones bind to secreted effector proteins and maintain them in a partially unfolded form competent for translocation by type III secretion systems/injectisomes. How diverse sets of effector-chaperone complexes are recognized by injectisomes is unclear. Here we describe a new mechanism of effector-chaperone recognition by the Chlamydia injectisome, a unique and ancestral line of these evolutionarily conserved secretion systems. By yeast two-hybrid analysis we identified networks of Chlamydia-specific proteins that interacted with the basal structure of the injectisome, including two hubs of protein-protein interactions that linked known secreted effector proteins to CdsQ, the putative cytoplasmic C-ring component of the secretion apparatus. One of these protein-interaction hubs is defined by Ct260/Mcsc (Multiple cargo secretion chaperone. Mcsc binds to and stabilizes at least two secreted hydrophobic proteins, Cap1 and Ct618, that localize to the membrane of the pathogenic vacuole ("inclusion". The resulting complexes bind to CdsQ, suggesting that in Chlamydia, the C-ring of the injectisome mediates the recognition of a subset of inclusion membrane proteins in complex with their chaperone. The selective recognition of inclusion membrane proteins by chaperones may provide a mechanism to co-ordinate the translocation of subsets of inclusion membrane proteins at different stages in infection.

  15. Secretion of Acid Sphingomyelinase is Affected by its Polymorphic Signal Peptide

    Directory of Open Access Journals (Sweden)

    Cosima Rhein

    2014-10-01

    Full Text Available Background: Acid sphingomyelinase (ASM catalyses the hydrolysis of sphingomyelin into ceramide, which acts as a lipid messenger that regulates important cellular functions. Deregulated ASM activity has been reported for different common diseases, but the mechanisms regulating ASM activity are still debated. ASM contains an exceptional signal peptide which is polymorphic due to a variable number of a hexanucleotide sequence that determines the length of the hydrophobic core. We investigated the impact of the signal peptide polymorphism on the regulation of ASM activity and secretion in vivo and in vitro. Methods and Results: Subjects homozygous for the rare 4-repeat allele displayed significantly lower secreted ASM activity than subjects homozygous for the common 6-repeat allele. In vitro, overexpression of ASM variants encoded by 2, 8 or 9 repeats resulted in a significantly lowered ASM secretion rate. Treatment of ASM-overexpressing cells with tumour necrosis factor α induced secretion of ASM, and the secretion rate was highest for the most common ASM variant encoding 6 repeats compared to other naturally occurring variants. Conclusion: We provide evidence that the polymorphic ASM signal peptide regulates ASM secretion. It might be an evolutionary mechanism to increase ASM secretion potential, whereas an increase in lysosomal ASM activity is limited due to deleterious cellular effects.

  16. Combined contributions of over-secreted glucagon-like peptide 1 and suppressed insulin secretion to hyperglycemia induced by gatifloxacin in rats

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Yunli, E-mail: chrisyu1255@yahoo.com.cn [Department of Pharmaceutics, The Second Affiliated Hospital of Soochow University, Suzhou 215004 (China); Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009 (China); Wang, Xinting, E-mail: wxinting1986@yahoo.com.cn [Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009 (China); Liu, Can, E-mail: ltsan@163.com [Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009 (China); Yao, Dan, E-mail: erinyao@126.com [Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009 (China); Shanghai Institute of Materia Medica, Shanghai 201203 (China); Hu, Mengyue, E-mail: juliahmy@126.com [Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009 (China); Li, Jia, E-mail: ljbzd@163.com [Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009 (China); Hu, Nan, E-mail: hn_324@163.com [Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009 (China); Liu, Li, E-mail: liulee@cpu.edu.cn [Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009 (China); Liu, Xiaodong, E-mail: xdliu@cpu.edu.cn [Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009 (China)

    2013-02-01

    Accumulating evidences have showed that gatifloxacin causes dysglycemia in both diabetic and non-diabetic patients. Our preliminary study demonstrated that gatifloxacin stimulated glucagon-like peptide 1 (GLP-1) secretion from intestinal cells. The aim of the study was to investigate the association between gatifloxacin-stimulated GLP-1 release and dysglycemia in both normal and streptozotocin-induced diabetic rats and explore the possible mechanisms. Oral administration of gatifloxacin (100 mg/kg/day and 200 mg/kg/day) for 3 and 12 days led to marked elevation of GLP-1 levels, accompanied by significant decrease in insulin levels and increase in plasma glucose. Similar results were found in normal rats treated with 3-day gatifloxacin. Gatifloxacin-stimulated GLP-1 release was further confirmed in NCI-H716 cells, which was abolished by diazoxide, a K{sub ATP} channel opener. QT-PCR analysis showed that gatifloxacin also upregulated expression of proglucagon and prohormone convertase 3 mRNA. To clarify the contradiction on elevated GLP-1 without insulinotropic effect, effects of GLP-1 and gatifloxacin on insulin release were investigated using INS-1 cells. We found that short exposure (2 h) to GLP-1 stimulated insulin secretion and biosynthesis, whereas long exposure (24 h and 48 h) to high level of GLP-1 inhibited insulin secretion and biosynthesis. Moreover, we also confirmed gatifloxacin acutely stimulated insulin secretion while chronically inhibited insulin biosynthesis. All the results gave an inference that gatifloxacin stimulated over-secretion of GLP-1, in turn, high levels of GLP-1 and gatifloxacin synergistically impaired insulin release, worsening hyperglycemia. -- Highlights: ► Gatifloxacin induced hyperglycemia both in diabetic rats and normal rats. ► Gatifloxacin enhanced GLP-1 secretion but inhibited insulin secretion in rats. ► Long-term exposure to high GLP-1 inhibited insulin secretion and biosynthesis. ► GLP-1 over-secretion may be

  17. Mechanisms of Action of Escapin, a Bactericidal Agent in the Ink Secretion of the Sea Hare Aplysia californica: Rapid and Long-Lasting DNA Condensation and Involvement of the OxyR-Regulated Oxidative Stress Pathway

    Science.gov (United States)

    Ko, Ko-Chun; Tai, Phang C.

    2012-01-01

    The marine snail Aplysia californica produces escapin, an l-amino acid oxidase, in its defensive ink. Escapin uses l-lysine to produce diverse products called escapin intermediate products of l-lysine (EIP-K), including α-amino-ε-caproic acid, Δ1-piperidine-2-carboxylic acid, and Δ2-piperidine-2-carboxylic acid. EIP-K and H2O2 together, but neither alone, is a powerful bactericide. Here, we report bactericidal mechanisms of escapin products on Escherichia coli. We show that EIP-K and H2O2 together cause rapid and long-lasting DNA condensation: 2-min treatment causes significant DNA condensation and killing, and 10-min treatment causes maximal effect, lasting at least 70 h. We isolated two mutants resistant to EIP-K plus H2O2, both having a single missense mutation in the oxidation regulatory gene, oxyR. A complementation assay showed that the mutated gene, oxyR(A233V), renders resistance to EIP-K plus H2O2, and a gene dosage effect leads to reduction of resistance for strains carrying wild-type oxyR. Temperature stress with EIP-K does not produce the bactericidal effect, suggesting the effect is due to a specific response to oxidative stress. The null mutant for any single DNA-binding protein—Dps, H-NS, Hup, Him, or MukB—was not resistant to EIP-K plus H2O2, suggesting that no single DNA-binding protein is necessary to mediate this bactericidal effect, but allowing for the possibility that EIP-K plus H2O2 could function through a combination of DNA-binding proteins. The bactericidal effect of EIP-K plus H2O2 was eliminated by the ferrous ion chelator 1,10-phenanthroline, and it was reduced by the hydroxyl radical scavenger thiourea, suggesting hydroxyl radicals mediate the effects of EIP-K plus H2O2. PMID:22232273

  18. "The Secret Garden": A Literary Journey.

    Science.gov (United States)

    Jordan, Anne Devereaux

    1998-01-01

    Outlines the life of Frances Hodgson Burnett, author of "The Secret Garden." Argues that it not only tells an enthralling tale, but takes readers on a journey through the history of English literature. Discusses the gothic tradition and romanticism of "The Secret Garden." Lists classic elements in the book and offers five ideas…

  19. Family Secrets: The Bioethics of Genetic Testing

    Science.gov (United States)

    Markowitz, Dina G.; DuPre, Michael J.; Holt, Susan; Chen, Shaw-Ree; Wischnowski, Michael

    2006-01-01

    This article discusses "Family Secrets," a problem-based learning (PBL) curriculum module that focuses on the bioethical implications of genetic testing. In high school biology classrooms throughout New York State, students are using "Family Secrets" to learn about DNA testing; Huntington's disease (HD); and the ethical, legal,…

  20. On Secret Sharing with Nonlinear Product Reconstruction

    DEFF Research Database (Denmark)

    Cascudo Pueyo, Ignacio; Cramer, Ronald; Mirandola, Diego

    2015-01-01

    Multiplicative linear secret sharing is a fundamental notion in the area of secure multiparty computation and, since recently, in the area of two-party cryptography as well. In a nutshell, this notion guarantees that the product of two secrets is obtained as a linear function of the vector consis...

  1. Autoregulation of enterochromaffin-like cell histamine secretion via the histamine 3 receptor subtype.

    OpenAIRE

    Kidd, M.; Tang, L. H.; Miu, K.; Lawton, G. P.; Sandor, A.; Modlin, I. M.

    1996-01-01

    INTRODUCTION: The neuroendocrine histamine-secreting cell of the gastric fundus, the enferochromaffin-like cell, is the principal regulator of parietal cell acid secretion. We have proposed that histamine may regulate its own synthesis and release via an autocrine mechanism. The purpose of this study was to evaluate the role of the histamine receptor subtypes H1, H2 and H3 in the regulation of this phenomenon. METHODS: Purified ECL cells were isolated by pronase digestion and EDTA exposure of...

  2. Regulation of Retinoschisin Secretion in Weri-Rb1 Cells by the F-Actin and Microtubule Cytoskeleton

    Science.gov (United States)

    Kitamura, Eiko; Gribanova, Yekaterina E.; Farber, Debora B.

    2011-01-01

    Retinoschisin is encoded by the gene responsible for X-linked retinoschisis (XLRS), an early onset macular degeneration that results in a splitting of the inner layers of the retina and severe loss in vision. Retinoschisin is predominantly expressed and secreted from photoreceptor cells as a homo-oligomer protein; it then associates with the surface of retinal cells and maintains the retina cellular architecture. Many missense mutations in the XLRS1 gene are known to cause intracellular retention of retinoschisin, indicating that the secretion process of the protein is a critical step for its normal function in the retina. However, the molecular mechanisms underlying retinoschisin's secretion remain to be fully elucidated. In this study, we investigated the role of the F-actin cytoskeleton in the secretion of retinoschisin by treating Weri-Rb1 cells, which are known to secrete retinoschisin, with cytochalasin D, jasplakinolide, Y-27632, and dibutyryl cGMP. Our results show that cytochalasin D and jasplakinolide inhibit retinoschisin secretion, whereas Y-27632 and dibutyryl cGMP enhance secretion causing F-actin alterations. We also demonstrate that high concentrations of taxol, which hyperpolymerizes microtubules, inhibit retinoschisin secretion. Our data suggest that retinoschisin secretion is regulated by the F-actin cytoskeleton, that cGMP or inhibition of ROCK alters F-actin structure enhancing the secretion, and that the microtubule cytoskeleton is also involved in this process. PMID:21738583

  3. Regulation of retinoschisin secretion in Weri-Rb1 cells by the F-actin and microtubule cytoskeleton.

    Directory of Open Access Journals (Sweden)

    Eiko Kitamura

    Full Text Available Retinoschisin is encoded by the gene responsible for X-linked retinoschisis (XLRS, an early onset macular degeneration that results in a splitting of the inner layers of the retina and severe loss in vision. Retinoschisin is predominantly expressed and secreted from photoreceptor cells as a homo-oligomer protein; it then associates with the surface of retinal cells and maintains the retina cellular architecture. Many missense mutations in the XLRS1 gene are known to cause intracellular retention of retinoschisin, indicating that the secretion process of the protein is a critical step for its normal function in the retina. However, the molecular mechanisms underlying retinoschisin's secretion remain to be fully elucidated. In this study, we investigated the role of the F-actin cytoskeleton in the secretion of retinoschisin by treating Weri-Rb1 cells, which are known to secrete retinoschisin, with cytochalasin D, jasplakinolide, Y-27632, and dibutyryl cGMP. Our results show that cytochalasin D and jasplakinolide inhibit retinoschisin secretion, whereas Y-27632 and dibutyryl cGMP enhance secretion causing F-actin alterations. We also demonstrate that high concentrations of taxol, which hyperpolymerizes microtubules, inhibit retinoschisin secretion. Our data suggest that retinoschisin secretion is regulated by the F-actin cytoskeleton, that cGMP or inhibition of ROCK alters F-actin structure enhancing the secretion, and that the microtubule cytoskeleton is also involved in this process.

  4. Characterization of a secreted Chlamydia protease

    DEFF Research Database (Denmark)

    Shaw, A.C.; Vandahl, B.B.; Larsen, M.R.

    2002-01-01

    Chlamydiae are obligate intracellular bacteria that are important human pathogens. The Chlamydia genomes contain orthologues to secretion apparatus proteins from other intracellular bacteria, but only a few secreted proteins have been identified. Most likely, effector proteins are secreted in order...... to promote infection. Effector proteins cannot be identified by motif or similarity searches. As a new strategy for identification of secreted proteins we have compared 2D-PAGE profiles of [35S]-labelled Chlamydia proteins from whole lysates of infected cells to 2D-PAGE profiles of proteins from purified...... Chlamydia. Several secretion candidates from Chlamydia trachomatis D and Chlamydia pneumoniae were detected by this method. Two protein spots were identified among the candidates. These represent fragments of the 'chlamydial protease- or proteasome-like activity factor' (CPAF) and were clearly present in 2D...

  5. Secret-key expansion from covert communication

    Science.gov (United States)

    Arrazola, Juan Miguel; Amiri, Ryan

    2018-02-01

    Covert communication allows the transmission of messages in such a way that it is not possible for adversaries to detect that the communication is occurring. This provides protection in situations where knowledge that two parties are talking to each other may be incriminating to them. In this work, we study how covert communication can be used for a different purpose: secret key expansion. First, we show that any message transmitted in a secure covert protocol is also secret and therefore unknown to an adversary. We then propose a covert communication protocol where the amount of key consumed in the protocol is smaller than the transmitted key, thus leading to secure secret key expansion. We derive precise conditions for secret key expansion to occur, showing that it is possible when there are sufficiently low levels of noise for a given security level. We conclude by examining how secret key expansion from covert communication can be performed in a computational security model.

  6. Ionizing radiation in secret services' conspirative actions

    International Nuclear Information System (INIS)

    Vogel, H.; Lotz, P.; Vogel, B.

    2007-01-01

    Introduction: The death of Litvinenko has been reported by the media. It has raised the question whether this case had been unique. The fall of the wall has allowed a glimpse in the planning and comporting of a secret service. Material and method: Documents of the secret service of the former German democratic republic (GDR), books of defectors, and media reports about secret service actions with radiating substances have been analyzed. Results: Since decades, secret services have been using radioactive nuclides and radiation for their tasks. Several killings with radiation have been reported. A complicated logistic had been developed. Conclusion: Only singular cases of the employment of radiating substances have become known. It is probable that the majority rests unknown. Government support seems necessary in secret services' conspirative actions with radiating substance

  7. Removal of Duodenum Elicits GLP-1 Secretion

    DEFF Research Database (Denmark)

    Muscogiuri, Giovanna; Mezza, Teresa; Prioletta, Annamaria

    2013-01-01

    OBJECTIVETo evaluate the effect of removal of the duodenum on the complex interplay between incretins, insulin, and glucagon in nondiabetic subjects.RESEARCH DESIGN AND METHODSFor evaluation of hormonal secretion and insulin sensitivity, 10 overweight patients without type 2 diabetes (age 61 ± 19......) secretion (P = 0.0004), while both fasting and postprandial glucose levels increased (P = 0.0001); GLP-1 and glucagon responses to the mixed meal increased significantly after surgery (P = 0.02 and 0.031). While changes in GIP levels did not correlate with insulin, glucagon, and glucose levels, the increase...... in GLP-1 secretion was inversely related to the postsurgery decrease in insulin secretion (R(2) = 0.56; P = 0.012) but not to the increased glucagon secretion, which correlated inversely with the reduction of insulin (R(2) = 0.46; P = 0.03) and C-peptide (R(2) = 0.37; P = 0.04). Given that the remaining...

  8. RNA Type III Secretion Signals that require Hfq

    Energy Technology Data Exchange (ETDEWEB)

    Niemann, George; Brown, Roslyn N.; Mushamiri, Ivy T.; Nguyen, Nhu T.; Taiwo, Rukayat; Stufkens, Afke; Smith, Richard D.; Adkins, Joshua N.; McDermott, Jason E.; Heffron, Fred

    2013-05-01

    effector proteins from the bacterium to a host cell; however, the secretion signal is poorly defined. Effector N-termini are thought to contain the signal, but they lack homology, possess no identifiable motif, and adopt intrinsically disordered structures. We identified a panel of RNA secretion signals that facilitated reporter translocation into host cells via a mechanism dependent upon the RNA chaperone Hfq. Each of these signals was localized to an RNA leader sequence preceding the translational start codon. To obtain this panel of RNA signals, we fused untranslated leader sequences from 42 different Salmonella effector proteins to the adenylate cyclase reporter (CyaA'), and tested each of them for translocation into J774 macrophages. RNA sequences derived from five effectors, gtgA, cigR, gogB, sseL, and steD were sufficient for CyaA' injection into host cells. The gtgA RNA also directed translocation of the β-lactamase reporter. To determine the mechanism of signal recognition, we identified proteins that bound specifically to the gtgA RNA. One of the unique proteins identified was Hfq. Translocation of all five UTR fusions was abolished in the Hfq mutant, confirming the importance of Hfq. Our results suggest that Hfq may direct a subset of RNA transcripts to the T3S apparatus for translation and secretion. Signal diversity may explain why the T3S signal has been difficult to define.

  9. Pancreatic ductal bicarbonate secretion: challenge of the acinar acid load

    Directory of Open Access Journals (Sweden)

    Peter eHegyi

    2011-07-01

    Full Text Available Acinar and ductal cells of the exocrine pancreas form a close functional unit. Although most studies contain data either on acinar or ductal cells, an increasing number of evidence highlights the importance of the pancreatic acinar-ductal functional unit. One of the best examples for this functional unit is the regulation of luminal pH by both cell types. Protons co-released during exocytosis from acini cause significant acidosis, whereas, bicarbonate secreted by ductal cells cause alkalization in the lumen. This suggests that the first and probably one of the most important role of bicarbonate secretion by pancreatic ductal cells is not only to neutralize the acid chyme entering into the duodenum from the stomach, but to neutralize acidic content secreted by acinar cells. To accomplish this role, it is more than likely that ductal cells have physiological sensing mechanisms which would allow them to regulate luminal pH. To date, four different classes of acid-sensing ion channels have been identified in the gastrointestinal tract (transient receptor potential ion channels, two-pore domain potassium channel, ionotropic purinoceptor and acid-sensing ion channel, however, none of these have been studied in pancreatic ductal cells. In this mini-review, we summarize our current knowledge of these channels and urge scientists to characterize ductal acid-sensing mechanisms and also to investigate the challenge of the acinar acid load on ductal cells.

  10. Incretins, insulin secretion and Type 2 diabetes mellitus

    DEFF Research Database (Denmark)

    Vilsbøll, Tina; Holst, Jens Møller

    2004-01-01

    the genes encoding their receptors have been deleted. In patients with Type 2 diabetes, the incretin effect is either greatly impaired or absent, and it is assumed that this could contribute to the inability of these patients to adjust their insulin secretion to their needs. In studies of the mechanism......When glucose is taken orally, insulin secretion is stimulated much more than it is when glucose is infused intravenously so as to result in similar glucose concentrations. This effect, which is called the incretin effect and is estimated to be responsible for 50 to 70% of the insulin response...... to glucose, is caused mainly by the two intestinal insulin-stimulating hormones, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). Their contributions have been confirmed in mimicry experiments, in experiments with antagonists of their actions, and in experiments where...

  11. Accurate prediction of secreted substrates and identification of a conserved putative secretion signal for type III secretion systems

    Energy Technology Data Exchange (ETDEWEB)

    Samudrala, Ram; Heffron, Fred; McDermott, Jason E.

    2009-04-24

    The type III secretion system is an essential component for virulence in many Gram-negative bacteria. Though components of the secretion system apparatus are conserved, its substrates, effector proteins, are not. We have used a machine learning approach to identify new secreted effectors. The method integrates evolutionary measures, such as the pattern of homologs in a range of other organisms, and sequence-based features, such as G+C content, amino acid composition and the N-terminal 30 residues of the protein sequence. The method was trained on known effectors from Salmonella typhimurium and validated on a corresponding set of effectors from Pseudomonas syringae, after eliminating effectors with detectable sequence similarity. The method was able to identify all of the known effectors in P. syringae with a specificity of 84% and sensitivity of 82%. The reciprocal validation, training on P. syringae and validating on S. typhimurium, gave similar results with a specificity of 86% when the sensitivity level was 87%. These results show that type III effectors in disparate organisms share common features. We found that maximal performance is attained by including an N-terminal sequence of only 30 residues, which agrees with previous studies indicating that this region contains the secretion signal. We then used the method to define the most important residues in this putative secretion signal. Finally, we present novel predictions of secreted effectors in S. typhimurium, some of which have been experimentally validated, and apply the method to predict secreted effectors in the genetically intractable human pathogen Chlamydia trachomatis. This approach is a novel and effective way to identify secreted effectors in a broad range of pathogenic bacteria for further experimental characterization and provides insight into the nature of the type III secretion signal.

  12. A preliminary study on the relationships between diurnal melatonin secretion profile and sleep variables in patients emergently admitted to the coronary care unit.

    Science.gov (United States)

    Takaesu, Yoshikazu; Futenma, Kunihiro; Kobayashi, Mina; Komada, Yoko; Tanaka, Nobuhiro; Yamashina, Akira; Inoue, Yuichi

    2015-01-01

    To clarify the significance of melatonin secretion under intensive care conditions, we investigated melatonin secretion profiles and sleep parameters of 23 patients just after admission to the coronary care unit (CCU) and 19 age-matched controls. Sleep parameters were evaluated by actigraphy, and melatonin secretion was assessed by measuring the urinary 6-sulphatoxy melatonin (6-SMT). 6-SMT secretion was lower and nocturnal sleep parameters were less satisfactory in the subjects than those in the controls, and there were positive correlations between these variables, particularly in the subject patients. The lowered melatonin secretion might be involved in the mechanism of insomnia in CCU patients.

  13. Identification of protein secretion systems and novel secreted proteins in Rhizobium leguminosarum bv. viciae

    Directory of Open Access Journals (Sweden)

    Krehenbrink Martin

    2008-01-01

    Full Text Available Abstract Background Proteins secreted by bacteria play an important role in infection of eukaryotic hosts. Rhizobia infect the roots of leguminous plants and establish a mutually beneficial symbiosis. Proteins secreted during the infection process by some rhizobial strains can influence infection and modify the plant defence signalling pathways. The aim of this study was to systematically analyse protein secretion in the recently sequenced strain Rhizobium leguminosarum bv. viciae 3841. Results Similarity searches using defined protein secretion systems from other Gram-negative bacteria as query sequences revealed that R. l. bv. viciae 3841 has ten putative protein secretion systems. These are the general export pathway (GEP, a twin-arginine translocase (TAT secretion system, four separate Type I systems, one putative Type IV system and three Type V autotransporters. Mutations in genes encoding each of these (except the GEP were generated, but only mutations affecting the PrsDE (Type I and TAT systems were observed to affect the growth phenotype and the profile of proteins in the culture supernatant. Bioinformatic analysis and mass fingerprinting of tryptic fragments of culture supernatant proteins identified 14 putative Type I substrates, 12 of which are secreted via the PrsDE, secretion system. The TAT mutant was defective for the symbiosis, forming nodules incapable of nitrogen fixation. Conclusion None of the R. l. bv. viciae 3841 protein secretion systems putatively involved in the secretion of proteins to the extracellular space (Type I, Type IV, Type V is required for establishing the symbiosis with legumes. The PrsDE (Type I system was shown to be the major route of protein secretion in non-symbiotic cells and to secrete proteins of widely varied size and predicted function. This is in contrast to many Type I systems from other bacteria, which typically secrete specific substrates encoded by genes often localised in close proximity to

  14. Regulation of prolactin secretion during pregnancy and lactation.

    Science.gov (United States)

    Voogt, J L; Lee, Y; Yang, S; Arbogast, L

    2001-01-01

    Prolactin plays major roles in maintaining the corpora lutea of pregnancy and in the synthesis of milk during lactation. The hypothalamic mechanisms involved in these functions have been investigated. Mating leads to a surge of prolactin and programs daily surges during early pregnancy. The expression of Fos-immunoreactivity shows that mating activates several hypothalamic nuclei, particularly the arcuate nucleus and medial preoptic area. In the arcuate nucleus, mating is associated with Fos expression in beta-endorphin neurons, and infusion of naloxone blocks both mating-induced and diurnal prolactin surges. Tyrosine hydroxylase-immunoreactive dopamine neurons appear not to participate in surge generation. However, after day 10 of gestation the secretion of placental lactogens suppresses prolactin secretion via activation of dopamine neurons without involvement of beta-endorphin neurons. Intracerebroventricular implantation of placental lactogen-secreting cells will block pregnancy prolactin surges, increase Fos expression in dopamine neurons, and increase tyrosine hydroxylase activity. During lactation the mechanisms regulating dopamine and beta-endorphin neurons are further modified. In early lactation a prolactin-induced increase in tyrosine hydroxylase activity leads to negative feedback, but this effect is lost by mid-lactation. Overriding this negative feedback is the inhibitory effect that suckling has on dopaminergic activity. This may involve beta-endorphin-mediated inhibition of dopamine neurons, as naloxone causes a marked increase in tyrosine hydroxylase activity and suppression of circulating prolactin. However, removal of tonic dopamine inhibition is not sufficient to account for the high levels of prolactin attained during lactation, and additional releasing factors are probably involved. In situ hybrization histochemistry for the most recent candidate, prolactin-releasing peptide, suggests that this may involve brain stem neurons that co

  15. VEGF secretion during hypoxia depends on free radicals-induced Fyn kinase activity in mast cells

    International Nuclear Information System (INIS)

    Garcia-Roman, Jonathan; Ibarra-Sanchez, Alfredo; Lamas, Monica; Gonzalez Espinosa, Claudia

    2010-01-01

    Research highlights: → Bone marrow-derived mast cells (BMMCs) secrete functional VEGF but do not degranulate after Cobalt chloride-induced hypoxia. → CoCl 2 -induced VEGF secretion in mast cells occurs by a Ca 2+ -insensitive but brefeldin A and Tetanus toxin-sensitive mechanism. → Trolox and N-acetylcysteine inhibit hypoxia-induced VEGF secretion but only Trolox inhibits FcεRI-dependent anaphylactic degranulation in mast cells. → Src family kinase Fyn activation after free radical production is necessary for hypoxia-induced VEGF secretion in mast cells. -- Abstract: Mast cells (MC) have an important role in pathologic conditions such as asthma and chronic obstructive pulmonary disease (COPD), where hypoxia conduce to deleterious inflammatory response. MC contribute to hypoxia-induced angiogenesis producing factors such as vascular endothelial growth factor (VEGF), but the mechanisms behind the control of hypoxia-induced VEGF secretion in this cell type is poorly understood. We used the hypoxia-mimicking agent cobalt chloride (CoCl 2 ) to analyze VEGF secretion in murine bone marrow-derived mast cells (BMMCs). We found that CoCl 2 promotes a sustained production of functional VEGF, able to induce proliferation of endothelial cells in vitro. CoCl 2 -induced VEGF secretion was independent of calcium rise but dependent on tetanus toxin-sensitive vesicle-associated membrane proteins (VAMPs). VEGF exocytosis required free radicals formation and the activation of Src family kinases. Interestingly, an important deficiency on CoCl 2 -induced VEGF secretion was observed in Fyn kinase-deficient BMMCs. Moreover, Fyn kinase was activated by CoCl 2 in WT cells and this activation was prevented by treatment with antioxidants such as Trolox and N-acetylcysteine. Our results show that BMMCs are able to release VEGF under hypoxic conditions through a tetanus toxin-sensitive mechanism, promoted by free radicals-dependent Fyn kinase activation.

  16. VEGF secretion during hypoxia depends on free radicals-induced Fyn kinase activity in mast cells

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Roman, Jonathan; Ibarra-Sanchez, Alfredo; Lamas, Monica [Departamento de Farmacobiologia, Centro de Investigacion y de Estudios Avanzados del IPN (Cinvestav, IPN) (Mexico); Gonzalez Espinosa, Claudia, E-mail: cgonzal@cinvestav.mx [Departamento de Farmacobiologia, Centro de Investigacion y de Estudios Avanzados del IPN (Cinvestav, IPN) (Mexico)

    2010-10-15

    Research highlights: {yields} Bone marrow-derived mast cells (BMMCs) secrete functional VEGF but do not degranulate after Cobalt chloride-induced hypoxia. {yields} CoCl{sub 2}-induced VEGF secretion in mast cells occurs by a Ca{sup 2+}-insensitive but brefeldin A and Tetanus toxin-sensitive mechanism. {yields} Trolox and N-acetylcysteine inhibit hypoxia-induced VEGF secretion but only Trolox inhibits Fc{epsilon}RI-dependent anaphylactic degranulation in mast cells. {yields} Src family kinase Fyn activation after free radical production is necessary for hypoxia-induced VEGF secretion in mast cells. -- Abstract: Mast cells (MC) have an important role in pathologic conditions such as asthma and chronic obstructive pulmonary disease (COPD), where hypoxia conduce to deleterious inflammatory response. MC contribute to hypoxia-induced angiogenesis producing factors such as vascular endothelial growth factor (VEGF), but the mechanisms behind the control of hypoxia-induced VEGF secretion in this cell type is poorly understood. We used the hypoxia-mimicking agent cobalt chloride (CoCl{sub 2}) to analyze VEGF secretion in murine bone marrow-derived mast cells (BMMCs). We found that CoCl{sub 2} promotes a sustained production of functional VEGF, able to induce proliferation of endothelial cells in vitro. CoCl{sub 2}-induced VEGF secretion was independent of calcium rise but dependent on tetanus toxin-sensitive vesicle-associated membrane proteins (VAMPs). VEGF exocytosis required free radicals formation and the activation of Src family kinases. Interestingly, an important deficiency on CoCl{sub 2}-induced VEGF secretion was observed in Fyn kinase-deficient BMMCs. Moreover, Fyn kinase was activated by CoCl{sub 2} in WT cells and this activation was prevented by treatment with antioxidants such as Trolox and N-acetylcysteine. Our results show that BMMCs are able to release VEGF under hypoxic conditions through a tetanus toxin-sensitive mechanism, promoted by free radicals

  17. Reappraisal of bicarbonate secretion by the human oesophagus

    DEFF Research Database (Denmark)

    Mertz-Nielsen, A; Hillingsø, J; Bukhave, Klaus

    1997-01-01

    BACKGROUND AND AIMS: Administration of omeprazole to healthy volunteers was recently reported to increase proximal duodenal mucosalbicarbonate secretion. As human oesophagus also secretes bicarbonate, the hypothesis was tested that omeprazole may stimulate oesophagealbicarbonate secretion and thu...

  18. On the regulation of ghrelin secretion

    International Nuclear Information System (INIS)

    Schmidt, A.

    2003-04-01

    The newly discovered endogenous ligand of the growth hormone secretagogue receptor, ghrelin, is not only a potent stimulus for growth hormone secretion, but exerts also potent orexigenic (appetite stimulatory) effects. The purpose of this thesis was to elucidate the mechanisms underlying the regulation of this peptide in three different studies. Ghrelin serum levels were analyzed with a commercially available radioimmunoassay (RIA). In 18 patients on chronic hemodialysis ghrelin levels were investigated and acetomorphine parameters were determined in order to correlate the nutritional status to the ghrelin serum levels. The potential elimination of ghrelin during dialysis was also tested. Ghrelin levels were significantly elevated compared to controls. No correlation was found between Ghrelin serum levels and anthropometric parameters. It can be speculated that chronic hemodialysis patients are not only resistant to growth hormone, but also to ghrelin. In 8 healthy volunteers a potential involvement of ghrelin in the response of growth hormone to acute exercise was tested. During three different exercise intensities (low, submaximal and maximal exercise) ghrelin levels were measured. No changes in ghrelin plasma concentrations could be detected. These findings suggest that ghrellin is not involved in the growth hormone response to acute exercise. The purpose of the third study was to enlighten the mechanisms underlying the postprandial decrease of ghrelin. During a double-blind placebo-controlled study increasing systemic glucose concentrations were attained with infusion of glucose, in order to represent fasting and postprandial conditions. Ghrelin levels were studied during coinfusion of insulin, somatostatin and placebo. It could be demonstrated that, the regulation of the postprandial decrease in ghrelin is not regulated by insulin or glucose, but by somatostatin. (author)

  19. Identification of a functional type VI secretion system in Campylobacter jejuni conferring capsule polysaccharide sensitive cytotoxicity

    NARCIS (Netherlands)

    Bleumink-Pluym, Nancy M C; van Alphen, Lieke B; Bouwman, Lieneke I; Wösten, MM; van Putten, Jos P M

    2013-01-01

    The pathogen Campylobacter jejuni is the principal cause of bacterial food-borne infections. The mechanism(s) that contribute to bacterial survival and disease are still poorly understood. In other bacterial species, type VI secretion systems (T6SS) are increasingly recognized to contribute to

  20. Distributed Multi-User Secret Sharing

    OpenAIRE

    Soleymani, Mahdi; Mahdavifar, Hessam

    2018-01-01

    A distributed secret sharing system is considered that consists of a dealer, $n$ storage nodes, and $m$ users. Each user is given access to a certain subset of storage nodes where it can download the data. The dealer wants to securely convey a specific secret $s_j$ to user $j$ via storage nodes, for $j=1,2,\\dots,m$, in such a way that no user gets any information about other users' secrets in an information-theoretic sense. To this end, we propose to study protocols where the dealer encodes s...

  1. Biliary and pancreatic secretions in abdominal irradiation

    International Nuclear Information System (INIS)

    Becciolini, A.; Cionini, L.; Cappellini, M.; Atzeni, G.

    1979-01-01

    The biliary and pancreatic secretions have been determined in patients given pelvic or para-aortic irradiation, with a dose of 50 Gy in the former group and between 36 and 40 Gy in the latter. A test meal containing polyethylene glycol (PEG) as reference substance was used. Each sample of the duodenal content was assayed for volume, PEG content, amylase and trypsin activity, pH and biliary secretion. No significant modifications of biliary and pancreatic secretions were demonstrated after irradiation, suggesting that these functions are not involved in the pathogenesis of the malabsorption radiation syndrome. (Auth.)

  2. Extracellular secretion of a recombinant therapeutic peptide by Bacillus halodurans utilizing a modified flagellin type III secretion system

    CSIR Research Space (South Africa)

    Berger, E

    2011-08-01

    Full Text Available Through modification of the flagellin type III secretion pathway of Bacillus halodurans heterologous peptides could be secreted into the medium as flagellin fusion monomers. The stability of the secreted monomers was significantly enhanced through...

  3. Thyrotropin secretion by thyrotropinomas is characterized by increased pulse frequency, delayed diurnal rhythm, enhanced basal secretion, spikiness, and disorderliness

    NARCIS (Netherlands)

    Roelfsema, Ferdinand; Pereira, Alberto M.; Keenan, Daniel M.; Veldhuis, Johannes D.; Romijn, Johannes A.

    2008-01-01

    Hormone secretion by somatotropinomas, corticotropinomas, and prolactinomas exhibits increased pulsatility and basal secretion, accompanied by greater disorderliness. Our objective was to evaluate TSH secretion by thyrotropinomas with up-to-date analytical and mathematical tools. Twenty-four hour

  4. Corticosteroid-Induced MKP-1 Represses Pro-Inflammatory Cytokine Secretion by Enhancing Activity of Tristetraprolin (TTP) in ASM Cells

    NARCIS (Netherlands)

    Prabhala, Pavan; Ammit, Alaina; Bunge, Kristin; Ge, Qi

    2016-01-01

    Exaggerated cytokine secretion drives pathogenesis of a number of chronic inflammatory diseases, including asthma. Anti-inflammatory pharmacotherapies, including corticosteroids, are front-line therapies and although they have proven clinical utility, the molecular mechanisms responsible for their

  5. Baseline Goblet Cell Mucin Secretion in the Airways Exceeds Stimulated Secretion over Extended Time Periods, and Is Sensitive to Shear Stress and Intracellular Mucin Stores.

    Directory of Open Access Journals (Sweden)

    Yunxiang Zhu

    Full Text Available Airway mucin secretion studies have focused on goblet cell responses to exogenous agonists almost to the exclusion of baseline mucin secretion (BLMS. In human bronchial epithelial cell cultures (HBECCs, maximal agonist-stimulated secretion exceeds baseline by ~3-fold as measured over hour-long periods, but mucin stores are discharged completely and require 24 h for full restoration. Hence, over 24 h, total baseline exceeds agonist-induced secretion by several-fold. Studies with HBECCs and mouse tracheas showed that BLMS is highly sensitive to mechanical stresses. Harvesting three consecutive 1 h baseline luminal incubations with HBECCs yielded equal rates of BLMS; however, lengthening the middle period to 72 h decreased the respective rate significantly, suggesting a stimulation of BLMS by the gentle washes of HBECC luminal surfaces. BLMS declined exponentially after washing HBECCs (t1/2 = 2.75 h, to rates approaching zero. HBECCs exposed to low perfusion rates exhibited spike-like increases in BLMS when flow was jumped 5-fold: BLMS increased >4 fold, then decreased within 5 min to a stable plateau at 1.5-2-fold over control. Higher flow jumps induced proportionally higher BLMS increases. Inducing mucous hyperplasia in HBECCs increased mucin production, BLMS and agonist-induced secretion. Mouse tracheal BLMS was ~6-fold higher during perfusion, than when flow was stopped. Munc13-2 null mouse tracheas, with their defect of accumulated cellular mucins, exhibited similar BLMS as WT, contrary to predictions of lower values. Graded mucous metaplasia induced in WT and Munc13-2 null tracheas with IL-13, caused proportional increases in BLMS, suggesting that naïve Munc13-2 mouse BLMS is elevated by increased mucin stores. We conclude that BLMS is, [i] a major component of mucin secretion in the lung, [ii] sustained by the mechanical activity of a dynamic lung, [iii] proportional to levels of mucin stores, and [iv] regulated differentially from agonist

  6. Orexin-A suppresses the pulsatile secretion of luteinizing hormone via beta-endorphin.

    Science.gov (United States)

    Irahara, M; Tamura, T; Matuzaki, T; Saito, S; Yasui, T; Yamano, S; Kamada, M; Aono, T

    2001-02-16

    Orexins, the novel hypothalamic neuropeptides that stimulate feeding behavior, have been shown to suppress the pulsatile secretion of LH in ovariectomized rats. However, the mechanism of this action is still not clear. We examined the effect of naloxone, a specific opioid antagonist, on the suppression of the pulsatile secretion of LH by orexins to determine whether beta-endorphin is involved in this suppressive effect. We administered orexins intracerebroventricularly and injected naloxone intravenously in ovariectomized rats, and we measured the serum LH concentration to analyze the pulsatile secretion. Administration of orexin-A significantly reduced the mean LH concentration and the pulse frequency, but coadministration of naloxone significantly restored the mean LH concentration and the pulse frequency. Administration of orexin-B also significantly reduced the mean LH concentration and the pulse frequency, and coadministration of naloxone did not restore them. These results indicate that orexin-A, but not orexin-B, suppresses GnRH secretion via beta-endorphin.

  7. Association of type 2 diabetes candidate polymorphisms in KCNQ1 with incretin and insulin secretion

    DEFF Research Database (Denmark)

    Müssig, Karsten; Staiger, Harald; Machicao, Fausto

    2009-01-01

    OBJECTIVE: KCNQ1 gene polymorphisms are associated with type 2 diabetes. This linkage appears to be mediated by altered beta-cell function. In an attempt to study underlying mechanisms, we examined the effect of four KCNQ1 single nucleotide polymorphisms (SNPs) on insulin secretion upon different...... C-peptide levels during OGTT, first-phase insulin secretion, and insulinogenic index after adjustment in the dominant model (all P insulin secretion indexes (all P ... and basal or stimulated incretin levels (all P > or = 0.05). CONCLUSIONS: Common genetic variation in KCNQ1 is associated with insulin secretion upon oral glucose load in a German population at increased risk of type 2 diabetes. The discrepancy between orally and intravenously administered glucose seems...

  8. EPCRA Trade Secret Form Instructions (PDF)

    Science.gov (United States)

    Detail on what information is required for each section of the form. Only the specific chemical identity required to be disclosed in EPCRA sections 303, 311,312, and 313 submissions may be claimed trade secret on the EPCRA report.

  9. Regulation of glucagon secretion by incretins

    DEFF Research Database (Denmark)

    Holst, Jens Juul; Christensen, M; Lund, A

    2011-01-01

    Glucagon secretion plays an essential role in the regulation of hepatic glucose production, and elevated fasting and postprandial plasma glucagon concentrations in patients with type 2 diabetes (T2DM) contribute to their hyperglycaemia. The reason for the hyperglucagonaemia is unclear, but recent...... studies have shown lack of suppression after oral but preserved suppression after isoglycaemic intravenous glucose, pointing to factors from the gut. Gastrointestinal hormones that are secreted in response to oral glucose include glucagon-like peptide-1 (GLP-1) that strongly inhibits glucagon secretion......, and GLP-2 and GIP, both of which stimulate secretion. When the three hormones are given together on top of isoglycaemic intravenous glucose, glucagon suppression is delayed in a manner similar to that observed after oral glucose. Studies with the GLP-1 receptor antagonist, exendin 9-39, suggest...

  10. Alcohol and gastric acid secretion in humans.

    Science.gov (United States)

    Chari, S; Teyssen, S; Singer, M V

    1993-06-01

    The secretory response of gastric acid to pure ethanol and alcoholic beverages may be different because the action of the non-ethanolic contents of the beverage may overwhelm that of ethanol. Pure ethanol in low concentrations (cognac) do not stimulate gastric acid secretion or release of gastrin. The powerful stimulants of gastric acid secretion present in beer, which are yet to be identified, are thermostable and anionic polar substances. The effect of chronic alcohol abuse on gastric acid secretion is not as predictable. Chronic alcoholic patients may have normal, enhanced, or diminished acid secretory capacity; hypochlorhydria being associated histologically with atrophic gastritis. There are no studies on the acute effect of alcohol intake on gastric acid secretion in chronic alcoholic patients. The acid stimulatory component of beer and wine needs to be characterised and its possible role in the causation of alcohol induced gastrointestinal diseases needs to be investigated.

  11. Pancreatic bicarbonate secretion involves two proton pumps

    DEFF Research Database (Denmark)

    Novak, Ivana; Wang, Jing; Henriksen, Katrine L.

    2011-01-01

    Pancreas secretes fluid rich in digestive enzymes and bicarbonate. The alkaline secretion is important in buffering of acid chyme entering duodenum and for activation of enzymes. This secretion is formed in pancreatic ducts, and studies to date show that plasma membranes of duct epithelium express...... H(+)/HCO(3)(-) transporters, which depend on gradients created by the Na(+)/K(+)-ATPase. However, the model cannot fully account for high-bicarbonate concentrations, and other active transporters, i.e. pumps, have not been explored. Here we show that pancreatic ducts express functional gastric...... localized to the plasma membranes of pancreatic ducts. Quantitative analysis of H(+)/HCO(3)(-) and fluid transport shows that the H(+)-K(+) pumps can contribute to pancreatic secretion in several species. Our results call for revision of the bicarbonate transport physiology in pancreas, and most likely...

  12. 5 CFR 2421.15 - Secret ballot.

    Science.gov (United States)

    2010-01-01

    ... FEDERAL LABOR RELATIONS AUTHORITY MEANING OF TERMS AS USED IN THIS SUBCHAPTER § 2421.15 Secret ballot... the person expressing such choice cannot be identified with the choice expressed, except in that...

  13. Cortisol regulates acid secretion of H+-ATPase-rich ionocytes in zebrafish (Danio rerio larvae

    Directory of Open Access Journals (Sweden)

    Chia-Hao eLin

    2015-11-01

    Full Text Available Systemic acid-base regulation is vital for physiological processes in vertebrates. Freshwater (FW fish live in an inconstant environment, and thus frequently face ambient acid stress. FW fish have to efficiently modulate their acid secretion processes for body fluid acid-base homeostasis during ambient acid challenge; hormonal control plays an important role in such physiological regulation. The hormone cortisol was previously proposed to be associated with acid base regulation in FW fish; however, the underlying mechanism has not been fully described. In the present study, mRNA expression of acid-secreting related transporters and cyp11b (encoding an enzyme involved in cortisol synthesis in zebrafish embryos was stimulated by treatment with acidic FW (AFW, pH 4.0 for 3 d. Exogenous cortisol treatment (20 mg/L, 3 d resulted in upregulated expression of transporters related to acidsecretionand increased acid secretion function at the organism level in zebrafish embryos. Moreover, cortisol treatment also significantly increased the acid secretion capacity of H+-ATPase-rich cells (HRCs at the cellular level. In loss-of-function experiments, microinjection of glucocorticoid receptor (GR morpholino (MO suppressed the expression of acid-secreting related transporters, and decreased acid secretion function at both the organism and cellular levels; on the other hand, mineralocorticoid receptor (MR MO did not induce any effects. Such evidence supports the hypothesized role of cortisol in fish acid-base regulation, and provides new insights into the roles of cortisol; cortisol-GR signaling stimulates zebrafish acid secretion function through transcriptional/translational regulation of the transporters and upregulation of acid secretion capacity in each acid-secreting ionocyte.

  14. Signaling Pathways in Exosomes Biogenesis, Secretion and Fate

    Directory of Open Access Journals (Sweden)

    Carla Emiliani

    2013-03-01

    Full Text Available Exosomes are small extracellular vesicles (30–100 nm derived from the endosomal system, which have raised considerable interest in the last decade. Several studies have shown that they mediate cell-to-cell communication in a variety of biological processes. Thus, in addition to cell-to-cell direct interaction or secretion of active molecules, they are now considered another class of signal mediators. Exosomes can be secreted by several cell types and retrieved in many body fluids, such as blood, urine, saliva and cerebrospinal fluid. In addition to proteins and lipids, they also contain nucleic acids, namely mRNA and miRNA. These features have prompted extensive research to exploit them as a source of biomarkers for several pathologies, such as cancer and neurodegenerative disorders. In this context, exosomes also appear attractive as gene delivery vehicles. Furthermore, exosome immunomodulatory and regenerative properties are also encouraging their application for further therapeutic purposes. Nevertheless, several issues remain to be addressed: exosome biogenesis and secretion mechanisms have not been clearly understood, and physiological functions, as well as pathological roles, are far from being satisfactorily elucidated.

  15. A secreted antibacterial neuropeptide shapes the microbiome of Hydra.

    Science.gov (United States)

    Augustin, René; Schröder, Katja; Murillo Rincón, Andrea P; Fraune, Sebastian; Anton-Erxleben, Friederike; Herbst, Eva-Maria; Wittlieb, Jörg; Schwentner, Martin; Grötzinger, Joachim; Wassenaar, Trudy M; Bosch, Thomas C G

    2017-09-26

    Colonization of body epithelial surfaces with a highly specific microbial community is a fundamental feature of all animals, yet the underlying mechanisms by which these communities are selected and maintained are not well understood. Here, we show that sensory and ganglion neurons in the ectodermal epithelium of the model organism hydra (a member of the animal phylum Cnidaria) secrete neuropeptides with antibacterial activity that may shape the microbiome on the body surface. In particular, a specific neuropeptide, which we call NDA-1, contributes to the reduction of Gram-positive bacteria during early development and thus to a spatial distribution of the main colonizer, the Gram-negative Curvibacter sp., along the body axis. Our findings warrant further research to test whether neuropeptides secreted by nerve cells contribute to the spatial structure of microbial communities in other organisms.Certain neuropeptides, in addition to their neuromodulatory functions, display antibacterial activities of unclear significance. Here, the authors show that a secreted neuropeptide modulates the distribution of bacterial communities on the body surface during development of the model organism Hydra.

  16. Cholecystokinin inhibits gastrin secretion independently of paracrine somatostatin secretion in the pig

    DEFF Research Database (Denmark)

    Schmidt, P T; Hansen, L; Hilsted, L

    2004-01-01

    BACKGROUND: Cholecystokinin inhibits the secretion of gastrin from antral G cells, an effect that is speculated to be mediated by D cells secreting somatostatin. The aim of the study was to test directly whether cholecystokinin inhibition of antral gastrin secretion is mediated by somatostatin....... METHODS: The effects of CCK on gastrin and somatostatin secretion were studied in isolated vascularly perfused preparations of pig antrum before and after immunoneutralization brought about by infusion of large amounts of a high affinity monoclonal antibody against somatostatin. RESULTS: CCK infusion...... at 10(-9) M and 10(-8) M decreased gastrin output to 70.5% +/- 7.6% (n = 8) and 76.3% +/- 3.6% (n = 7) of basal output, respectively. CCK at 10(-10) M had no effect (n = 6). Somatostatin secretion was dose-dependently increased by CCK infusion and increased to 268 +/- 38.2% (n = 7) of basal secretion...

  17. Type IV secretion and Brucella virulence.

    Science.gov (United States)

    Boschiroli, Maria Laura; Ouahrani-Bettache, Safia; Foulongne, Vincent; Michaux-Charachon, Sylvie; Bourg, Gisele; Allardet-Servent, Annick; Cazevieille, Chantal; Lavigne, Jean-Phillipe; Liautard, Jean Pierre; Ramuz, Michel; O'Callaghan, David

    2002-12-20

    The type IV secretion system, encoded by the virB region, is a key virulence factor for Brucella. The 12 genes of the region form an operon that is specifically induced by phagosome acidification in cells after phagocytosis. We speculate that the system serves to secrete unknown effector molecules, which allow Brucella to pervert the host cell endosomal pathways and to create a novel intracellular compartment in which it can replicate. Copyright 2002 Elsevier Science B.V.

  18. (LH) secretion in fasted prepubertal ewes

    African Journals Online (AJOL)

    DR. NJ TONUKARI

    2012-01-10

    Jan 10, 2012 ... inhibitory day lengths in female Siberian hamsters. Horm Behav. 52(4): 492-498. Novaira H, Ng Y, Wolfe A, Radovick S (2009). Kisspeptin increases. GnRH mRNA expression and secretion in GnRH secreting neuronal cell lines. Mol. Cell Endocrinol. 311(1-2): 126-134. Ojeda S, Prevot V, Heger S, Lomniczi ...

  19. Matryoshka: Hiding Secret Communication in Plain Sight

    OpenAIRE

    Safaka, Iris; Fragouli, Christina; Argyraki, Katerina

    2016-01-01

    We want to enable a pair of communicating users to exchange secret messages while hiding the fact that secret communication is taking place. We propose a linguistic steganography approach, where each human message is hidden in another human-like message. A hard open question is how to keep the steganographic message small -- existing related tools tend to blow up its size, thereby revealing the use of steganography. We encrypt by compressing each message, mapping it to a plausible sequence of...

  20. Peptides and neurotransmitters that affect renin secretion

    Science.gov (United States)

    Ganong, W. F.; Porter, J. P.; Bahnson, T. D.; Said, S. I.

    1984-01-01

    Substance P inhibits renin secretion. This polypeptide is a transmitter in primary afferent neurons and is released from the peripheral as well as the central portions of these neurons. It is present in afferent nerves from the kidneys. Neuropeptide Y, which is a cotransmitter with norepinephrine and epinephrine, is found in sympathetic neurons that are closely associated with and presumably innervate the juxtagolmerular cells. Its effect on renin secretion is unknown, but it produces renal vasoconstriction and natriuresis. Vasoactive intestinal polypeptide (VIP) is a cotransmitter with acetylocholine in cholinergic neurons, and this polypeptide stimulates renin secretion. We cannot find any evidence for its occurence in neurons in the kidneys, but various stimuli increase plasma VIP to levels comparable to those produced by doses of exogenous VIP which stimulated renin secretion. Neostigmine increases plasma VIP and plasma renin activity, and the VIP appears to be responsible for the increase in renin secretion, since the increase is not blocked by renal denervation or propranolol. Stimulation of various areas in the brain produces sympathetically mediated increases in plasma renin activity associated with increases in blood pressure. However, there is pharmacological evidence that the renin response can be separated from the blood pressure response. In anaesthetized dogs, drugs that increase central serotonergic discharge increase renin secretion without increasing blood pressure. In rats, activation of sertonergic neurons in the dorsal raphe nucleus increases renin secretion by a pathway that projects from this nucleus to the ventral hypothalamus, and from there to the kidneys via the sympathetic nervous system. The serotonin releasing drug parachloramphetamine also increases plasma VIP, but VIP does not appear to be the primary mediator of the renin response. There is preliminary evidence that the serotonergic neurons in the dorsal raphe nucleus are part of the

  1. Physiological and Molecular Analysis of Aluminium-Induced Organic Acid Anion Secretion from Grain Amaranth (Amaranthus hypochondriacus L.) Roots

    Science.gov (United States)

    Fan, Wei; Xu, Jia-Meng; Lou, He-Qiang; Xiao, Chuan; Chen, Wei-Wei; Yang, Jian-Li

    2016-01-01

    Grain amaranth (Amaranthus hypochondriacus L.) is abundant in oxalate and can secrete oxalate under aluminium (Al) stress. However, the features of Al-induced secretion of organic acid anions (OA) and potential genes responsible for OA secretion are poorly understood. Here, Al-induced OA secretion in grain amaranth roots was characterized by ion charomatography and enzymology methods, and suppression subtractive hybridization (SSH) together with quantitative real-time PCR (qRT-PCR) was used to identify up-regulated genes that are potentially involved in OA secretion. The results showed that grain amaranth roots secrete both oxalate and citrate in response to Al stress. The secretion pattern, however, differs between oxalate and citrate. Neither lanthanum chloride (La) nor cadmium chloride (Cd) induced OA secretion. A total of 84 genes were identified as up-regulated by Al, in which six genes were considered as being potentially involved in OA secretion. The expression pattern of a gene belonging to multidrug and toxic compound extrusion (MATE) family, AhMATE1, was in close agreement with that of citrate secretion. The expression of a gene encoding tonoplast dicarboxylate transporter and four genes encoding ATP-binding cassette transporters was differentially regulated by Al stress, but the expression pattern was not correlated well with that of oxalate secretion. Our results not only reveal the secretion pattern of oxalate and citrate from grain amaranth roots under Al stress, but also provide some genetic information that will be useful for further characterization of genes involved in Al toxicity and tolerance mechanisms. PMID:27144562

  2. Physiological and Molecular Analysis of Aluminium-Induced Organic Acid Anion Secretion from Grain Amaranth (Amaranthus hypochondriacus L. Roots

    Directory of Open Access Journals (Sweden)

    Wei Fan

    2016-04-01

    Full Text Available Grain amaranth (Amaranthus hypochondriacus L. is abundant in oxalate and can secrete oxalate under aluminium (Al stress. However, the features of Al-induced secretion of organic acid anions (OA and potential genes responsible for OA secretion are poorly understood. Here, Al-induced OA secretion in grain amaranth roots was characterized by ion charomatography and enzymology methods, and suppression subtractive hybridization (SSH together with quantitative real-time PCR (qRT-PCR was used to identify up-regulated genes that are potentially involved in OA secretion. The results showed that grain amaranth roots secrete both oxalate and citrate in response to Al stress. The secretion pattern, however, differs between oxalate and citrate. Neither lanthanum chloride (La nor cadmium chloride (Cd induced OA secretion. A total of 84 genes were identified as up-regulated by Al, in which six genes were considered as being potentially involved in OA secretion. The expression pattern of a gene belonging to multidrug and toxic compound extrusion (MATE family, AhMATE1, was in close agreement with that of citrate secretion. The expression of a gene encoding tonoplast dicarboxylate transporter and four genes encoding ATP-binding cassette transporters was differentially regulated by Al stress, but the expression pattern was not correlated well with that of oxalate secretion. Our results not only reveal the secretion pattern of oxalate and citrate from grain amaranth roots under Al stress, but also provide some genetic information that will be useful for further characterization of genes involved in Al toxicity and tolerance mechanisms.

  3. Information Flow in Secret Sharing Protocols

    Directory of Open Access Journals (Sweden)

    Elham Kashefi

    2009-11-01

    Full Text Available The entangled graph states have emerged as an elegant and powerful quantum resource, indeed almost all multiparty protocols can be written in terms of graph states including measurement based quantum computation (MBQC, error correction and secret sharing amongst others. In addition they are at the forefront in terms of implementations. As such they represent an excellent opportunity to move towards integrated protocols involving many of these elements. In this paper we look at expressing and extending graph state secret sharing and MBQC in a common framework and graphical language related to flow. We do so with two main contributions. First we express in entirely graphical terms which set of players can access which information in graph state secret sharing protocols. These succinct graphical descriptions of access allow us to take known results from graph theory to make statements on the generalisation of the previous schemes to present new secret sharing protocols. Second, we give a set of necessary conditions as to when a graph with flow, i.e. capable of performing a class of unitary operations, can be extended to include vertices which can be ignored, pointless measurements, and hence considered as unauthorised players in terms of secret sharing, or error qubits in terms of fault tolerance. This offers a way to extend existing MBQC patterns to secret sharing protocols. Our characterisation of pointless measurements is believed also to be a useful tool for further integrated measurement based schemes, for example in constructing fault tolerant MBQC schemes.

  4. Development of secreted proteins as biotherapeutic agents.

    Science.gov (United States)

    Bonin-Debs, Angelika L; Boche, Irene; Gille, Hendrik; Brinkmann, Ulrich

    2004-04-01

    As one of the most important classes of proteins, secreted factors account for about one-tenth of the human genome, 3000 - 4000 in total, including factors of signalling pathways, blood coagulation and immune defence, as well as digestive enzymes and components of the extracellular matrix. Secreted proteins are a rich source of new therapeutics and drug targets, and are currently the focus of major drug discovery programmes throughout the industry. Many of the most important novel drugs developed in biotechnology have resulted from the application of secreted proteins as therapeutics. Secreted proteins often circulate throughout the body and, therefore, have access to most organs and tissues. Because of that, many of the factors are themselves therapeutic agents. This paper gives an overview on the features and functions of human secreted proteins and peptides, as well as strategies by which to discover additional therapeutic proteins from the human 'secretome'. Furthermore, a variety of examples are provided for the therapeutic use of recombinant secreted proteins as 'biologicals', including features and applications of recombinant antibodies, erythropoietin, insulin, interferon, plasminogen activators, growth hormone and colony-stimulating factors.

  5. Pituitary adenylate cyclase-activating polypeptide promotes eccrine gland sweat secretion.

    Science.gov (United States)

    Sasaki, S; Watanabe, J; Ohtaki, H; Matsumoto, M; Murai, N; Nakamachi, T; Hannibal, J; Fahrenkrug, J; Hashimoto, H; Watanabe, H; Sueki, H; Honda, K; Miyazaki, A; Shioda, S

    2017-02-01

    Sweat secretion is the major function of eccrine sweat glands; when this process is disturbed (paridrosis), serious skin problems can arise. To elucidate the causes of paridrosis, an improved understanding of the regulation, mechanisms and factors underlying sweat production is required. Pituitary adenylate cyclase-activating polypeptide (PACAP) exhibits pleiotropic functions that are mediated via its receptors [PACAP-specific receptor (PAC1R), vasoactive intestinal peptide (VIP) receptor type 1 (VPAC1R) and VPAC2R]. Although some studies have suggested a role for PACAP in the skin and several exocrine glands, the effects of PACAP on the process of eccrine sweat secretion have not been examined. To investigate the effect of PACAP on eccrine sweat secretion. Reverse transcriptase-polymerase chain reaction and immunostaining were used to determine the expression and localization of PACAP and its receptors in mouse and human eccrine sweat glands. We injected PACAP subcutaneously into the footpads of mice and used the starch-iodine test to visualize sweat-secreting glands. Immunostaining showed PACAP and PAC1R expression by secretory cells from mouse and human sweat glands. PACAP immunoreactivity was also localized in nerve fibres around eccrine sweat glands. PACAP significantly promoted sweat secretion at the injection site, and this could be blocked by the PAC1R-antagonist PACAP6-38. VIP, an agonist of VPAC1R and VPAC2R, failed to induce sweat secretion. This is the first report demonstrating that PACAP may play a crucial role in sweat secretion via its action on PAC1R located in eccrine sweat glands. The mechanisms underlying the role of PACAP in sweat secretion may provide new therapeutic options to combat sweating disorders. © 2016 British Association of Dermatologists.

  6. Sex differences in the hypothalamic control of prolactin secretion

    International Nuclear Information System (INIS)

    Grattan, D.R.; Liu, L.; Bunn, S.J.

    2001-01-01

    Full text: Sex differences in the brain may arise from the organisational effects of exposure to sex steroids during development, or from the exposure to a differential hormonal milieu in the adult. There is a marked sex difference in the neuroendocrine mechanism that regulates prolactin secretion. Levels of prolactin in the blood are higher in females than in males. Similarly, basal activity of tuberoinfundibular dopamine (TIDA) neurons, which are involved in the tonic suppression of prolactin secretion, are two fold higher in females than in males. Prolactin is known to stimulate the activity of TIDA neurons, thereby regulating its own secretion by short-loop feedback. Hence, it is thought that elevated TIDA neuronal activity in females is induced by increased prolactin in the blood. We have recently demonstrated that prolactin stimulation of TIDA neurons requires the transcription factor, STAT5b. We have now investigated prolactin secretion in male and female STAT5b-deficient mice, to test the hypothesis that sex differences in TIDA neuronal activity are dependent on stimulation by prolactin acting through STAT5b. Prolactin levels in blood were measured by radioimmunoassay, and TIDA activity was assessed by measuring concentrations of the dopamine metabolite DOPAC in the median eminence by HPLC, and by measuring tyrosine hydroxylase mRNA in the arcuate nucleus by real-time RT-PCR. The data demonstrate marked gender differences in the activity of TIDA neurons. While TIDA activity in STAT5b-deficient mice was reduced compared to wild type, the sex difference persisted. Since STAT5b is required for the actions of prolactin on these neurons, we can conclude that the sexual dimorphism in brain function is independent of gender differences in blood levels of prolactin. It seems likely that differential exposure to gonadal steroid hormones, either during development or in adulthood, might underlie the sex difference in TIDA neuronal activity. Copyright (2001

  7. Cadmium inhibits acid secretion in stimulated frog gastric mucosa

    International Nuclear Information System (INIS)

    Gerbino, Andrea; Debellis, Lucantonio; Caroppo, Rosa; Curci, Silvana; Colella, Matilde

    2010-01-01

    Cadmium, a toxic environmental pollutant, affects the function of different organs such as lungs, liver and kidney. Less is known about its toxic effects on the gastric mucosa. The aim of this study was to investigate the mechanisms by which cadmium impacts on the physiology of gastric mucosa. To this end, intact amphibian mucosae were mounted in Ussing chambers and the rate of acid secretion, short circuit current (I sc ), transepithelial potential (V t ) and resistance (R t ) were recorded in the continuous presence of cadmium. Addition of cadmium (20 μM to 1 mM) on the serosal but not luminal side of the mucosae resulted in inhibition of acid secretion and increase in NPPB-sensitive, chloride-dependent short circuit current. Remarkably, cadmium exerted its effects only on histamine-stimulated tissues. Experiments with TPEN, a cell-permeant chelator for heavy metals, showed that cadmium acts from the intracellular side of the acid secreting cells. Furthermore, cadmium-induced inhibition of acid secretion and increase in I sc cannot be explained by an action on: 1) H 2 histamine receptor, 2) Ca 2+ signalling 3) adenylyl cyclase or 4) carbonic anhydrase. Conversely, cadmium was ineffective in the presence of the H + /K + -ATPase blocker omeprazole suggesting that the two compounds likely act on the same target. Our findings suggest that cadmium affects the functionality of histamine-stimulated gastric mucosa by inhibiting the H + /K + -ATPase from the intracellular side. These data shed new light on the toxic effect of this dangerous environmental pollutant and may result in new avenues for therapeutic intervention in acute and chronic intoxication.

  8. Proteomic identification of secreted proteins of Propionibacterium acnes

    Science.gov (United States)

    2010-01-01

    Background The anaerobic Gram-positive bacterium Propionibacterium acnes is a human skin commensal that resides preferentially within sebaceous follicles; however, it also exhibits many traits of an opportunistic pathogen, playing roles in a variety of inflammatory diseases such as acne vulgaris. To date, the underlying disease-causing mechanisms remain ill-defined and knowledge of P. acnes virulence factors remains scarce. Here, we identified proteins secreted during anaerobic cultivation of a range of skin and clinical P. acnes isolates, spanning the four known phylogenetic groups. Results Culture supernatant proteins of P. acnes were separated by two-dimensional electrophoresis (2-DE) and all Coomassie-stained spots were subsequently identified by MALDI mass spectrometry (MALDI-MS). A set of 20 proteins was secreted in the mid-exponential growth phase by the majority of strains tested. Functional annotation revealed that many of these common proteins possess degrading activities, including glycoside hydrolases with similarities to endoglycoceramidase, β-N-acetylglucosaminidase and muramidase; esterases such as lysophospholipase and triacylglycerol lipase; and several proteases. Other secreted factors included Christie-Atkins-Munch-Petersen (CAMP) factors, glyceraldehyde 3-phosphate dehydrogenase (GAPDH), and several hypothetical proteins, a few of which are unique to P. acnes. Strain-specific differences were apparent, mostly in the secretion of putative adhesins, whose genes exhibit variable phase variation-like sequence signatures. Conclusions Our proteomic investigations have revealed that the P. acnes secretome harbors several proteins likely to play a role in host-tissue degradation and inflammation. Despite a large overlap between the secretomes of all four P. acnes phylotypes, distinct differences between predicted host-tissue interacting proteins were identified, providing potential insight into the differential virulence properties of P. acnes isolates

  9. Proteomic identification of secreted proteins of Propionibacterium acnes

    Directory of Open Access Journals (Sweden)

    Holland Carsten

    2010-08-01

    Full Text Available Abstract Background The anaerobic Gram-positive bacterium Propionibacterium acnes is a human skin commensal that resides preferentially within sebaceous follicles; however, it also exhibits many traits of an opportunistic pathogen, playing roles in a variety of inflammatory diseases such as acne vulgaris. To date, the underlying disease-causing mechanisms remain ill-defined and knowledge of P. acnes virulence factors remains scarce. Here, we identified proteins secreted during anaerobic cultivation of a range of skin and clinical P. acnes isolates, spanning the four known phylogenetic groups. Results Culture supernatant proteins of P. acnes were separated by two-dimensional electrophoresis (2-DE and all Coomassie-stained spots were subsequently identified by MALDI mass spectrometry (MALDI-MS. A set of 20 proteins was secreted in the mid-exponential growth phase by the majority of strains tested. Functional annotation revealed that many of these common proteins possess degrading activities, including glycoside hydrolases with similarities to endoglycoceramidase, β-N-acetylglucosaminidase and muramidase; esterases such as lysophospholipase and triacylglycerol lipase; and several proteases. Other secreted factors included Christie-Atkins-Munch-Petersen (CAMP factors, glyceraldehyde 3-phosphate dehydrogenase (GAPDH, and several hypothetical proteins, a few of which are unique to P. acnes. Strain-specific differences were apparent, mostly in the secretion of putative adhesins, whose genes exhibit variable phase variation-like sequence signatures. Conclusions Our proteomic investigations have revealed that the P. acnes secretome harbors several proteins likely to play a role in host-tissue degradation and inflammation. Despite a large overlap between the secretomes of all four P. acnes phylotypes, distinct differences between predicted host-tissue interacting proteins were identified, providing potential insight into the differential virulence

  10. Subglottic Secretion Drainage and Objective Outcomes: A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Caroff, Daniel A; Li, Lingling; Muscedere, John; Klompas, Michael

    2016-04-01

    Current guidelines recommend endotracheal tubes with subglottic secretion drainage to prevent ventilator-associated pneumonia. Subglottic secretion drainage is associated with fewer ventilator-associated pneumonia diagnoses, but it is unclear to what extent this reflects fewer invasive pneumonias versus fewer false-positive diagnoses due to less secretions and/or less microbial colonization of the oropharynx. We, therefore, undertook a systematic review and meta-analysis of the impact of subglottic secretion drainage on duration of mechanical ventilation, ICU and hospital length of stay, ventilator-associated events, mortality, antibiotic utilization, stridor, and reintubations to better understand the net benefits and limitations of this intervention. We searched Cumulative Index to Nursing and Allied Health Literature, Excerpta Medica Database, and PubMed from inception through February 22, 2015, without language restrictions. Randomized controlled trials comparing subglottic secretion drainage versus no subglottic secretion drainage in adult patients on mechanical ventilation. Eligible trials were abstracted and assessed for risk of bias by two reviewers. We identified 17 eligible trials with a total of 3,369 patients. Subglottic secretion drainage was associated with lower ventilator-associated pneumonia rates (risk ratio, 0.58; 95% CI, 0.51-0.67; I2 = 0%), but there were no significant differences between groups in duration of mechanical ventilation (weighted mean difference, -0.16 d; 95% CI, -0.64 to 0.33; I2 = 0%), ICU length of stay (weighted mean difference, +0.17 d; 95% CI, -0.62 to 0.95; I2 = 0%), hospital length of stay (weighted mean difference, -0.57 d; 95% CI, -2.44 to 1.30; I2 = 0%), ventilator-associated events (risk ratio, 0.97; 95% CI, 0.65-1.43), or mortality (risk ratio, 0.93; 95% CI, 0.84-1.03; I2 = 0%). Two studies observed significantly less antibiotic use with subglottic secretion drainage whereas a third did not. There were no significant

  11. Competitive Inhibition of Renal Tubular Secretion of Gemifloxacin by Probenecid▿

    Science.gov (United States)

    Landersdorfer, Cornelia B.; Kirkpatrick, Carl M. J.; Kinzig, Martina; Bulitta, Jürgen B.; Holzgrabe, Ulrike; Drusano, George L.; Sörgel, Fritz

    2009-01-01

    Probenecid interacts with transport processes of drugs at several sites in the body. For most quinolones, renal clearance is reduced by concomitant administration of probenecid. The interaction between gemifloxacin and probenecid has not yet been studied. We studied the extent, time course, site(s), and mechanism of this interaction. Seventeen healthy volunteers participated in a randomized, two-way crossover study. Subjects received 320 mg gemifloxacin as an oral tablet without and with 4.5 g probenecid divided in eight oral doses. Drug concentrations in plasma and urine were analyzed by liquid chromatography-tandem mass spectrometry. WinNonlin was used for noncompartmental analysis, compartmental modeling, and statistics, and NONMEM was used for visual predictive checks. Concomitant administration of probenecid increased plasma gemifloxacin concentrations and amounts excreted in urine compared to baseline amounts. Data are average estimates (percent coefficients of variation). Modeling showed a competitive inhibition of the renal tubular secretion of gemifloxacin by probenecid as the most likely mechanism of the interaction. The estimated Km and Vmax for the saturable part of renal elimination were 9.16 mg/liter (20%) and 113 mg/h (21%), respectively. Based on the molar ratio, the affinity for the renal transporter was 10-fold higher for gemifloxacin than for probenecid. Since probenecid reached an ∼200-times-higher area under the molar concentration-time curve from 0 to 24 h than gemifloxacin, probenecid inhibited the active tubular secretion of gemifloxacin. Probenecid also reduced the nonrenal clearance of gemifloxacin from 25.2 (26%) to 21.0 (23%) liters/h. Probenecid inhibited the renal tubular secretion of gemifloxacin, most likely by a competitive mechanism, and slightly decreased nonrenal clearance of gemifloxacin. PMID:19564368

  12. Competitive inhibition of renal tubular secretion of gemifloxacin by probenecid.

    Science.gov (United States)

    Landersdorfer, Cornelia B; Kirkpatrick, Carl M J; Kinzig, Martina; Bulitta, Jürgen B; Holzgrabe, Ulrike; Drusano, George L; Sörgel, Fritz

    2009-09-01

    Probenecid interacts with transport processes of drugs at several sites in the body. For most quinolones, renal clearance is reduced by concomitant administration of probenecid. The interaction between gemifloxacin and probenecid has not yet been studied. We studied the extent, time course, site(s), and mechanism of this interaction. Seventeen healthy volunteers participated in a randomized, two-way crossover study. Subjects received 320 mg gemifloxacin as an oral tablet without and with 4.5 g probenecid divided in eight oral doses. Drug concentrations in plasma and urine were analyzed by liquid chromatography-tandem mass spectrometry. WinNonlin was used for noncompartmental analysis, compartmental modeling, and statistics, and NONMEM was used for visual predictive checks. Concomitant administration of probenecid increased plasma gemifloxacin concentrations and amounts excreted in urine compared to baseline amounts. Data are average estimates (percent coefficients of variation). Modeling showed a competitive inhibition of the renal tubular secretion of gemifloxacin by probenecid as the most likely mechanism of the interaction. The estimated K(m) and Vmax for the saturable part of renal elimination were 9.16 mg/liter (20%) and 113 mg/h (21%), respectively. Based on the molar ratio, the affinity for the renal transporter was 10-fold higher for gemifloxacin than for probenecid. Since probenecid reached an approximately 200-times-higher area under the molar concentration-time curve from 0 to 24 h than gemifloxacin, probenecid inhibited the active tubular secretion of gemifloxacin. Probenecid also reduced the nonrenal clearance of gemifloxacin from 25.2 (26%) to 21.0 (23%) liters/h. Probenecid inhibited the renal tubular secretion of gemifloxacin, most likely by a competitive mechanism, and slightly decreased nonrenal clearance of gemifloxacin.

  13. Hsp60 is actively secreted by human tumor cells.

    Directory of Open Access Journals (Sweden)

    Anna M Merendino

    2010-02-01

    Full Text Available Hsp60, a Group I mitochondrial chaperonin, is classically considered an intracellular chaperone with residence in the mitochondria; nonetheless, in the last few years it has been found extracellularly as well as in the cell membrane. Important questions remain pertaining to extracellular Hsp60 such as how generalized is its occurrence outside cells, what are its extracellular functions and the translocation mechanisms that transport the chaperone outside of the cell. These questions are particularly relevant for cancer biology since it is believed that extracellular chaperones, like Hsp70, may play an active role in tumor growth and dissemination.Since cancer cells may undergo necrosis and apoptosis, it could be possible that extracellular Hsps are chiefly the result of cell destruction but not the product of an active, physiological process. In this work, we studied three tumor cells lines and found that they all release Hsp60 into the culture media by an active mechanism independently of cell death. Biochemical analyses of one of the cell lines revealed that Hsp60 secretion was significantly reduced, by inhibitors of exosomes and lipid rafts.Our data suggest that Hsp60 release is the result of an active secretion mechanism and, since extracellular release of the chaperone was demonstrated in all tumor cell lines investigated, our observations most likely reflect a general physiological phenomenon, occurring in many tumors.

  14. Renin secretion and total body sodium: Pathways of integrative control

    DEFF Research Database (Denmark)

    Bie, Peter; Damkjaer, Mads

    2009-01-01

    Abstract 1. We review mechanisms of sodium balance operating at constant mean arterial blood pressure (MABP), i.e., conditions where MABP does not provide the primary signal to the kidney. 2. Relative constancy of body fluids requires accurate regulation of total body sodium (TBS). Normally, plenty...... of sodium is ingested, and balance achieved by control of renal excretion driven by multiple central nervous, cardiovascular, endocrine, and renal tubular mechanisms. Subtle changes in sodium balance are associated with parallel changes in extracellular volume (due to fast and precise osmoregulation......) proximal tubular reabsorption involving glomerulo-tubular balance (GTB) and neurohumoral control, (iii) macula densa mechanisms influencing TGF and renin secretion, and (iv) distal tubular reabsorption dominated by the renin-angiotensin-aldosterone system (RAAS). 4. The review focuses on the interactive...

  15. Loss of Cln3 impacts protein secretion in the social amoeba Dictyostelium.

    Science.gov (United States)

    Huber, Robert J

    2017-07-01

    Neuronal ceroid lipofuscinosis (NCL), also referred to as Batten disease, is the most common form of childhood neurodegeneration. Mutations in CLN3 cause the most prevalent subtype of the disease, which manifests during early childhood and is currently untreatable. The precise function of the CLN3 protein is still not known, which has inhibited the development of targeted therapies. In the social amoeba Dictyostelium discoideum, loss of the CLN3 homolog, Cln3, reduces adhesion during early development, which delays streaming and aggregation. The results of the present study indicate that this phenotype may be at least partly due to aberrant protein secretion in cln3 - cells. It is well-established that Cln3 localizes primarily to the contractile vacuole (CV) system in Dictyostelium, and to a lesser extent, compartments of the endocytic pathway. Intriguingly, the CV system has been linked to the secretion of proteins that do not contain a signal peptide for secretion (i.e., unconventional protein secretion). Proteins that do contain a signal peptide are secreted via a conventional mechanism involving the endoplasmic reticulum, transport through the Golgi, and secretion via vesicle release. In this study, Cln3 was observed to co-localize with the Golgi marker wheat germ agglutinin suggesting that Cln3 participates in both secretion mechanisms. Chimeras of wild-type (WT) and cln3 - cells displayed delayed streaming and aggregation, and interestingly, cln3 - cells starved in conditioned media (CM) harvested from starving WT cells showed near normal timing of streaming and aggregation suggesting aberrant protein secretion in Cln3-deficient cells. Based on these observations, LC-MS/MS was used to reveal the protein content of CM from starved cells (mass spectrometry data are available via ProteomeXchange with identifier PXD004897). A total of 450 proteins were detected in WT and cln3 - CM, of which 3 were absent in cln3 - CM. Moreover, 12 proteins that were present in

  16. Role of Nitric Oxide in the Regulation of Renin and Vasopressin Secretion

    Science.gov (United States)

    Reid, Ian A.

    1994-01-01

    Research during recent years has established nitric oxide as a unique signaling molecule that plays important roles in the regulation of the cardiovascular, nervous, immune, and other systems. Nitric oxide has also been implicated in the control of the secretion of hormones by the pancreas, hypothalamus, and anterior pituitary gland, and evidence is accumulating that it contributes to the regulation of the secretion of renin and vasopressin, hormones that play key roles in the control of sodium and water balance. Several lines of evidence have implicated nitric oxide in the control of renin secretion. The enzyme nitric oxide synthase is present in vascular and tubular elements of the kidney, particularly in cells of the macula densa, a structure that plays an important role in the control of renin secretion. Guanylyl cyclase, a major target for nitric oxide, is also present in the kidney. Drugs that inhibit nitric oxide synthesis generally suppress renin release in vivo and in vitro, suggesting a stimulatory role for the L-arginine/nitric oxide pathway in the control of renin secretion. Under some conditions, however, blockade of nitric oxide synthesis increases renin secretion. Recent studies indicate that nitric oxide not only contributes to the regulation of basal renin secretion, but also participates in the renin secretory responses to activation of the renal baroreceptor, macula densa, and beta adrenoceptor mechanisms that regulate renin secretion. Histochemical and immunocytochemical studies have revealed the presence of nitric oxide synthase in the supraoptic and paraventricular nuclei of the hypothalamus and in the posterior pituitary gland. Colocalization of nitric oxide synthase and vasopressin has been demonstrated in some hypothalamic neurons. Nitric oxide synthase activity in the hypothalamus and pituitary is increased by maneuvers known to stimulate vasopressin secretion, including salt loading and dehydration, Administration of L-arginine and nitric

  17. Analysis of chemical profiles of insect adhesion secretions by gas chromatography–mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Reitz, Manuela [Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 8, 72076 Tübingen (Germany); Gerhardt, Heike [Institute of Pharmaceutical Sciences, University of Tübingen, Auf der Morgenstelle 8, 72076 Tübingen (Germany); Schmitt, Christian; Betz, Oliver [Institute of Evolution and Ecology, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen (Germany); Albert, Klaus, E-mail: klaus.albert@uni-tuebingen.de [Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 8, 72076 Tübingen (Germany); Lämmerhofer, Michael, E-mail: michael.laemmerhofer@uni-tuebingen.de [Institute of Pharmaceutical Sciences, University of Tübingen, Auf der Morgenstelle 8, 72076 Tübingen (Germany)

    2015-01-07

    aldehydes. Especially, hydrocarbons with >C40 carbon numbers have previously been rarely reported for insect secretions. The results suggest that the investigated insect secretions are complex emulsions which allow the attachment of tarsi on various otherwise incompatible materials of smooth and rough surfaces. The solid consistence of the established alkanes at ambient temperatures might contribute to a semi-solid consistence of the adhesive, amalgamating partly opposing functions such as slip resistance, tarsal release, desiccation resistance, and mechanical compliance. The methods developed can be extended to other similar applications of studying compositions of insect secretions of other species.

  18. Exocytosis and protein secretion in Trypanosoma

    Directory of Open Access Journals (Sweden)

    Rossignol Michel

    2010-01-01

    Full Text Available Abstract Background Human African trypanosomiasis is a lethal disease caused by the extracellular parasite Trypanosoma brucei. The proteins secreted by T. brucei inhibit the maturation of dendritic cells and their ability to induce lymphocytic allogenic responses. To better understand the pathogenic process, we combined different approaches to characterize these secreted proteins. Results Overall, 444 proteins were identified using mass spectrometry, the largest parasite secretome described to date. Functional analysis of these proteins revealed a strong bias toward folding and degradation processes and to a lesser extent toward nucleotide metabolism. These features were shared by different strains of T. brucei, but distinguished the secretome from published T. brucei whole proteome or glycosome. In addition, several proteins had not been previously described in Trypanosoma and some constitute novel potential therapeutic targets or diagnostic markers. Interestingly, a high proportion of these secreted proteins are known to have alternative roles once secreted. Furthermore, bioinformatic analysis showed that a significant proportion of proteins in the secretome lack transit peptide and are probably not secreted through the classical sorting pathway. Membrane vesicles from secretion buffer and infested rat serum were purified on sucrose gradient and electron microscopy pictures have shown 50- to 100-nm vesicles budding from the coated plasma membrane. Mass spectrometry confirmed the presence of Trypanosoma proteins in these microvesicles, showing that an active exocytosis might occur beyond the flagellar pocket. Conclusions This study brings out several unexpected features of the secreted proteins and opens novel perspectives concerning the survival strategy of Trypanosoma as well as possible ways to control the disease. In addition, concordant lines of evidence support the original hypothesis of the involvement of microvesicle-like bodies in the

  19. 30 CFR 47.81 - Provisions for withholding trade secrets.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Provisions for withholding trade secrets. 47.81... TRAINING HAZARD COMMUNICATION (HazCom) Trade Secret Hazardous Chemical § 47.81 Provisions for withholding trade secrets. (a) Operators may withhold the identity of a trade secret chemical, including the name...

  20. Recursive Secret Sharing for Distributed Storage and Information Hiding

    OpenAIRE

    Parakh, Abhishek; Kak, Subhash

    2010-01-01

    This paper presents a recursive computational multi-secret sharing technique that hides k-2 secrets of size b each into n shares of a single secret S of size b, such that any k of the n shares suffice to recreate the secret S as well as all the hidden secrets. This may act as a steganographic channel to transmit hidden information or used for authentication and verification of shares and the secret itself. Further, such a recursive technique may be used as a computational secret sharing techn...

  1. Trade Secrets in Life Science and Pharmaceutical Companies

    OpenAIRE

    Nealey, Tara; Daignault, Ronald M.; Cai, Yu

    2015-01-01

    Trade secret protection arises under state common law and state statutes. In general, a trade secret is information that is not generally known to the public and is maintained as a secret, and it provides a competitive advantage or economic benefit to the trade secret holder. Trade secrets can be worth tens or hundreds of millions of dollars, and damage awards in trade secret litigation have been high; often, there is a lot at stake. Obtaining a trade secret through ?improper means? is misapp...

  2. CFTR Influences Beta Cell Function and Insulin Secretion Through Non-Cell Autonomous Exocrine-Derived Factors.

    Science.gov (United States)

    Sun, Xingshen; Yi, Yaling; Xie, Weiliang; Liang, Bo; Winter, Michael C; He, Nan; Liu, Xiaoming; Luo, Meihui; Yang, Yu; Ode, Katie Larson; Uc, Aliye; Norris, Andrew W; Engelhardt, John F

    2017-10-01

    Although β-cell dysfunction in cystic fibrosis (CF) leads to diabetes, the mechanism by which the cystic fibrosis transmembrane conductance regulator (CFTR) channel influences islet insulin secretion remains debated. We investigated the CFTR-dependent islet-autonomous mechanisms affecting insulin secretion by using islets isolated from CFTR knockout ferrets. Total insulin content was lower in CF as compared with wild-type (WT) islets. Furthermore, glucose-stimulated insulin secretion (GSIS) was impaired in perifused neonatal CF islets, with reduced first, second, and amplifying phase secretion. Interestingly, CF islets compensated for reduced insulin content under static low-glucose conditions by secreting a larger fraction of islet insulin than WT islets, probably because of elevated SLC2A1 transcripts, increased basal inhibition of adenosine triphosphate-sensitive potassium channels (K-ATP), and elevated basal intracellular Ca2+. Interleukin (IL)-6 secretion by CF islets was higher relative to WT, and IL-6 treatment of WT ferret islets produced a CF-like phenotype with reduced islet insulin content and elevated percentage insulin secretion in low glucose. CF islets exhibited altered expression of INS, CELA3B, and several β-cell maturation and proliferation genes. Pharmacologic inhibition of CFTR reduced GSIS by WT ferret and human islets but similarly reduced insulin secretion and intracellular Ca2+ in CFTR knockout ferret islets, indicating that the mechanism of action is not through CFTR. Single-molecule fluorescent in situ hybridization, on isolated ferret and human islets and ferret pancreas, demonstrated that CFTR RNA colocalized within KRT7+ ductal cells but not endocrine cells. These results suggest that CFTR affects β-cell function via a paracrine mechanism involving proinflammatory factors secreted from islet-associated exocrine-derived cell types. Copyright © 2017 Endocrine Society.

  3. Secretion Trap Tagging of Secreted and Membrane-Spanning Proteins Using Arabidopsis Gene Traps

    Science.gov (United States)

    Andrew T. Groover; Joseph R. Fontana; Juana M. Arroyo; Cristina Yordan; W. Richard McCombie; Robert A. Martienssen

    2003-01-01

    Secreted and membrane-spanning proteins play fundamental roles in plant development but pose challenges for genetic identification and characterization. We describe a "secretion trap" screen for gene trap insertions in genes encoding proteins routed through the secretory pathway. The gene trap transposon encodes a ß-glucuronidase reporter enzyme...

  4. Meaningful Share Generation for Increased Number of Secrets in Visual Secret-Sharing Scheme

    Directory of Open Access Journals (Sweden)

    Mustafa Ulutas

    2010-01-01

    Full Text Available This paper presents a new scheme for hiding two halftone secret images into two meaningful shares created from halftone cover images. Meaningful shares are more desirable than noise-like (meaningless shares in Visual Secret Sharing because they look natural and do not attract eavesdroppers' attention. Previous works in the field focus on either increasing number of secrets or creating meaningful shares for one secret image. The method outlined in this paper both increases the number of secrets and creates meaningful shares at the same time. While the contrast ratio of shares is equal to that of Extended Visual Cryptography, two secrets are encoded into two shares as opposed to one secret in the Extended Visual Cryptography. Any two natural-looking images can be used as cover unlike the Halftone Visual Cryptography method where one cover should be the negative of the other cover image and can only encode one secret. Effectiveness of the proposed method is verified by an experiment.

  5. Incretin hormone secretion over the day

    DEFF Research Database (Denmark)

    Ahren, B; Carr, RD; Deacon, Carolyn F.

    2010-01-01

    The two incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are key factors in the regulation of islet function and glucose metabolism, and incretin-based therapy for type 2 diabetes has gained considerable interest during recent years. Regulat......The two incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are key factors in the regulation of islet function and glucose metabolism, and incretin-based therapy for type 2 diabetes has gained considerable interest during recent years....... Regulation of incretin hormone secretion is less well characterized. The main stimulus for incretin hormone secretion is presence of nutrients in the intestinal lumen, and carbohydrate, fat as well as protein all have the capacity to stimulate GIP and GLP-1 secretion. More recently, it has been established...... that a diurnal regulation exists with incretin hormone secretion to an identical meal being greater when the meal is served in the morning compared to in the afternoon. Finally, whether incretin hormone secretion is altered in disease states is an area with, so far, controversial results in different studies...

  6. Functional anatomy and physiology of gastric secretion.

    Science.gov (United States)

    Schubert, Mitchell L

    2015-11-01

    This review summarizes the past year's literature regarding the neuroendocrine and intracellular regulation of gastric acid secretion, discussing both basic and clinical aspects. Gastric acid facilitates the digestion of protein as well as the absorption of iron, calcium, vitamin B12, and certain medications. High acidity kills ingested microorganisms and limits bacterial overgrowth, enteric infection, and possibly spontaneous bacterial peritonitis. The main stimulants of acid secretion are gastrin, released from antral gastrin cells; histamine, released from oxyntic enterochromaffin-like cells; and acetylcholine, released from antral and oxyntic intramural neurons. Ghrelin and coffee also stimulate acid secretion whereas somatostatin, cholecystokinin, glucagon-like peptide-1, and atrial natriuretic peptide inhibit acid secretion. Although 95% of parietal cells are contained within the oxyntic mucosa (fundus and body), 50% of human antral glands contain parietal cells. Proton pump inhibitors are considered well tolerated drugs, but concerns have been raised regarding dysbiosis, atrophic gastritis, hypergastrinemia, hypomagnesemia, and enteritis/colitis. Our understanding of the functional anatomy and physiology of gastric secretion continues to advance. Such knowledge is crucial for improved management of acid-peptic disorders, prevention and management of neoplasia, and the development of novel medications.

  7. Coronary artery calcification and cardiovascular disease in children with chronic kidney disease.

    Science.gov (United States)

    Paoli, Sara; Mitsnefes, Mark M

    2014-04-01

    Cardiovascular disease is the leading cause of death in children and young adults with end-stage renal disease (ESRD). As adults, children with advanced chronic kidney disease (CKD) have extremely high prevalence of traditional and uremia-related cardiovascular risk factors. Coronary artery calcification is one of the earliest cardiovascular markers detected in children with ESRD. The purpose of this review is to examine the new developments in pathogenesis of coronary artery calcification and to describe recently published studies on this topic in children with CKD. There is growing evidence that fibroblast growth factor 23 (FGF23) and Klotho factor play a key role in the development of coronary artery calcification in ESRD. Recent studies have shown that induction of vascular calcification begins in early normophosphatemic CKD by the reduction of vascular Klotho and increased FGF23 secretion. Pediatric studies confirmed the presence of abnormal FGF23 and Klotho metabolism and the association of increased circulating FGF23 with coronary artery calcification in children with CKD. New developments in our understanding of the mechanisms of vascular calcification in patients with early CKD require further investigation of whether control of FGF23/Klotho metabolism will prevent or delay the development of coronary artery calcification and other cardiovascular outcomes.

  8. Unconventional secretion of tissue transglutaminase involves phospholipid-dependent delivery into recycling endosomes.

    Directory of Open Access Journals (Sweden)

    Evgeny A Zemskov

    2011-04-01

    Full Text Available Although endosomal compartments have been suggested to play a role in unconventional protein secretion, there is scarce experimental evidence for such involvement. Here we report that recycling endosomes are essential for externalization of cytoplasmic secretory protein tissue transglutaminase (tTG. The de novo synthesized cytoplasmic tTG does not follow the classical ER/Golgi-dependent secretion pathway, but is targeted to perinuclear recycling endosomes, and is delivered inside these vesicles prior to externalization. On its route to the cell surface tTG interacts with internalized β1 integrins inside the recycling endosomes and is secreted as a complex with recycled β1 integrins. Inactivation of recycling endosomes, blocking endosome fusion with the plasma membrane, or downregulation of Rab11 GTPase that controls outbound trafficking of perinuclear recycling endosomes, all abrogate tTG secretion. The initial recruitment of cytoplasmic tTG to recycling endosomes and subsequent externalization depend on its binding to phosphoinositides on endosomal membranes. These findings begin to unravel the unconventional mechanism of tTG secretion which utilizes the long loop of endosomal recycling pathway and indicate involvement of endosomal trafficking in non-classical protein secretion.

  9. Chemical composition of metapleural gland secretions of fungus-growing and non-fungus-growing ants.

    Science.gov (United States)

    Vieira, Alexsandro S; Morgan, E David; Drijfhout, Falko P; Camargo-Mathias, Maria I

    2012-10-01

    The metapleural gland is exclusive to ants, and unusual among exocrine glands in having no mechanism for closure and retention of secretion. As yet, no clear conclusion has been reached as to the function of metapleural gland secretion. Metapleural gland secretions were investigated for fungus-growing ants representing the derived attines Trachymyrmex fuscus, Atta laevigata, and Acromyrmex coronatus, the basal attines Apterostigma pilosum and Mycetarotes parallelus, and non-fungus-growing ants of the tribes Ectatommini (Ectatomma brunneum) and Myrmicini (Pogonomyrmex naegeli). Our results showed that the secretions of leaf-cutting ants (A. laevigata and A. coronatus) and the derived attine, T. fuscus, contain a greater variety and larger quantities of volatile compounds than those of myrmicine and ectatommine ants. The most abundant compounds found in the metapleural glands of A. laevigata and A. coronatus were hydroxyacids, and phenylacetic acid (only in A. laevigata). Indole was present in all groups examined, while skatole was found in large quantities only in attines. Ketones and aldehydes are present in the secretion of some attines. Esters are present in the metapleural gland secretion of all species examined, although mainly in A. laevigata, A. coronatus, and T. fuscus. Compared with basal attines and non-fungus-growing ants, the metapleural glands of leaf-cutting ants produce more acidic compounds that may have an antibiotic or antifungal function.

  10. Gram-Negative Bacterial Lipopolysaccharide Stimulates Activin A Secretion from Human Amniotic Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Yumiko Abe

    2013-01-01

    Full Text Available Activin A is involved in inflammation. The present study was performed to clarify if lipopolysaccharide, a component of Gram-negative bacteria, stimulates activin A secretion from human amniotic epithelial cells and to determine if activin A plays a role in amnionitis. Fetal membranes were obtained during elective cesarean sections performed in full-term pregnancies of patients without systemic disease, signs of premature delivery, or fetal complications. Amniotic epithelial cells were isolated by trypsinization. The activin A concentrations in the culture media were measured by enzyme-linked immunosorbent assay, and cell proliferation was assessed by 5-bromo-2′-deoxyuridine incorporation. Amniotic epithelial cells secreted activin A in a cell density-dependent manner, and lipopolysaccharide (10 μg/mL enhanced the secretion at each cell density. Lipopolysaccharide (10–50 μg/mL also stimulated activin A secretion in a dose-dependent manner. Contrary to the effect of activin A secretion, lipopolysaccharide inhibited cell proliferation in amniotic epithelial cells. The present study suggests that lipopolysaccharide stimulation of activin A secretion may be a mechanism in the pathogenesis of amnionitis.

  11. Regulation of pineal melatonin secretion: comparison between mammals and birds.

    Science.gov (United States)

    Mess, B; Rékási, Z; Ghosh, M; Csernus, V

    1996-01-01

    The melatonin secretory pattern of the perifused rat and chicken pineal was compared in response to different lighting conditions and norepinephrine administration. The following main differences were observed. 1. Explanted (perifused) rat pineal showed, after a rapid initial surge, a steady continuous basal secretion of melatonin. This was independent from the day-night (light-dark) periods. Chicken pineal, however, showed a characteristic daily rhythm of melatonin production with peak in the dark and nadir in the light phase. 2. This daily rhythm could not be extinguished by keeping the pineal donor birds in constant light- or constant dark environment for at least 2 weeks immediately before sacrifice. 3. Short light impulse (5 min), applied in the middle of the dark phase, was ineffective in birds. Keeping the perifusion chambers in continuous light or darkness, however, depressed the amplitude of the circadian rhythm even in the next cycle. 4. Rat pineal responds to norepinephrine stimulation with a dose-related increase of melatonin release, independently from the phase of the day, while in the chicken, norepinephrine slightly inhibits both the diurnal and the nocturnal level of melatonin secretion. 5. It can be inferred that melatonin secretion of the mammalian pineal gland is primarily regulated by a peripheral (sympathetic) innervation. This is modulated, under in vivo circumstances, by different environmental factors, mainly by light conditions transmitted by neural mechanisms. In contrast, the primary secretory process of the avian pineal is based on an intrinsic circadian rhythm. This might be genetically coded or maintained by yet unknown neurohormonal mechanisms and/or external factors (e.g. magnetic fields). This fairly stable circadian rhythm is only modulated by environmental lighting conditions.

  12. Extracellular secretion of Carocin S1 in Pectobacterium carotovorum subsp. carotovorum occurs via the type III secretion system integral to the bacterial flagellum.

    Science.gov (United States)

    Chan, Yung-Chieh; Wu, Huang-Pin; Chuang, Duen-Yau

    2009-08-27

    Pectobacterium carotovorum subsp. carotovorum is a phytopathogenic enterobacterium responsible for soft rot, a disease characterized by extensive maceration of the affected plant tissue. This species also produces two or more antibacterial substances called bacteriocins, which enhance its competitiveness against related rival species. However, the secretion mechanism for low-molecular-weight bacteriocin is still unknown. A mutant (flhC::Tn5) that did not secrete the low-molecular-weight bacteriocin (LMWB), Carocin S1, was generated by Tn5 insertional mutagenesis. Sequence analysis indicated that this insertion disrupted open reading frame 2 (ORF2) and ORF3 of this strain. Deletion and rescue experiments indicated that ORF2 and ORF3 were both required for extracellular LMWB secretion. The ORF2 and ORF3 sequences showed high homology with the flhD and flhC gene sequences of Pectobacterium carotovorum subsp. atroseptica, Serratia marcescens, Yersinia enterocolitica, and Escherichia coli, indicating that they likely encoded key regulatory components of the type III flagella secretion system. Thus, the extracellular export of Carocin S1 by Pectobacterium carotovorum subsp. carotovorum appears to utilize the type III secretion system integral to bacterial flagella.

  13. Extracellular secretion of Carocin S1 in Pectobacterium carotovorum subsp. carotovorum occurs via the type III secretion system integral to the bacterial flagellum

    Directory of Open Access Journals (Sweden)

    Chuang Duen-yau

    2009-08-01

    Full Text Available Abstract Background Pectobacterium carotovorum subsp. carotovorum is a phytopathogenic enterobacterium responsible for soft rot, a disease characterized by extensive maceration of the affected plant tissue. This species also produces two or more antibacterial substances called bacteriocins, which enhance its competitiveness against related rival species. However, the secretion mechanism for low-molecular-weight bacteriocin is still unknown. Results A mutant (flhC::Tn5 that did not secrete the low-molecular-weight bacteriocin (LMWB, Carocin S1, was generated by Tn5 insertional mutagenesis. Sequence analysis indicated that this insertion disrupted open reading frame 2 (ORF2 and ORF3 of this strain. Deletion and rescue experiments indicated that ORF2 and ORF3 were both required for extracellular LMWB secretion. The ORF2 and ORF3 sequences showed high homology with the flhD and flhC gene sequences of Pectobacterium carotovorum subsp. atroseptica, Serratia marcescens, Yersinia enterocolitica, and Escherichia coli, indicating that they likely encoded key regulatory components of the type III flagella secretion system. Conclusion Thus, the extracellular export of Carocin S1 by Pectobacterium carotovorum subsp. carotovorum appears to utilize the type III secretion system integral to bacterial flagella.

  14. The role of somatostatin in GLP-1-induced inhibition of glucagon secretion in mice

    DEFF Research Database (Denmark)

    Ørgaard, Anne; Holst, Jens J

    2017-01-01

    AIMS/HYPOTHESIS: Glucagon-like peptide-1 (GLP-1) receptor agonists are currently used for the treatment of type 2 diabetes. Their main mechanism of action is enhancement of glucose-induced insulin secretion (from increased beta cell glucose sensitivity) and inhibition of glucagon secretion...... effect of GLP-1 was preserved at hypoglycaemic levels, leaving unanswered the question of how this is avoided in vivo in individuals treated with GLP-1 receptor agonists........ The latter has been demonstrated to account for about half of their blood glucose-lowering activity. Whereas the effect of GLP-1 on insulin secretion is clearly dependent on ambient glucose concentrations and has been described in detail, the mechanism responsible for the inhibitory effect of GLP-1...

  15. Two outer membrane proteins are required for maximal type I secretion of the Caulobacter crescentus S-layer protein.

    Science.gov (United States)

    Toporowski, Michael C; Nomellini, John F; Awram, Peter; Smit, John

    2004-12-01

    Transport of RsaA, the crystalline S-layer subunit protein of Caulobacter crescentus, is mediated by a type I secretion mechanism. Two proteins have been identified that play the role of the outer membrane protein (OMP) component in the RsaA secretion machinery. The genes rsaF(a) and rsaF(b) were identified by similarity to the Escherichia coli hemolysin secretion OMP TolC by using the C. crescentus genome sequence. The rsaF(a) gene is located several kilobases downstream of the other transporter genes, while rsaF(b) is completely unlinked. An rsaF(a) knockout had approximately 56% secretion compared to wild-type levels, while the rsaF(b) knockout reduced secretion levels to approximately 79%. When expression of both proteins was eliminated, there was no RsaA secretion, but a residual level of approximately 9% remained inside the cell, suggesting posttranslational autoregulation. Complementation with either of the individual rsaF genes by use of a multicopy vector, which resulted in 8- to 10-fold overexpression of the proteins, did not restore RsaA secretion to wild-type levels, indicating that both rsaF genes were required for full-level secretion. However, overexpression of rsaF(a) (with normal rsaF(b) levels) in concert with overexpression of rsaA resulted in a 28% increase in RsaA secretion, indicating a potential for significantly increasing expression levels of an already highly expressing type I secretion system. This is the only known example of type I secretion requiring two OMPs to assemble a fully functional system.

  16. Protease-activated receptor 2 mediates mucus secretion in the airway submucosal gland.

    Directory of Open Access Journals (Sweden)

    Hyun Jae Lee

    Full Text Available Protease-activated receptor 2 (PAR2, a G protein-coupled receptor expressed in airway epithelia and smooth muscle, plays an important role in airway inflammation. In this study, we demonstrated that activation of PAR2 induces mucus secretion from the human airway gland and examined the underlying mechanism using the porcine and murine airway glands. The mucosa with underlying submucosal glands were dissected from the cartilage of tissues, pinned with the mucosal side up at the gas/bath solution interface of a physiological chamber, and covered with oil so that secretions from individual glands could be visualized as spherical bubbles in the oil. Secretion rates were determined by optical monitoring of the bubble diameter. The Ca(2+-sensitive dye Fura2-AM was used to determine intracellular Ca(2+ concentration ([Ca(2+](i by means of spectrofluorometry. Stimulation of human tracheal mucosa with PAR2-activating peptide (PAR2-AP elevated intracellular Ca(2+ and induced glandular secretion equal to approximately 30% of the carbachol response in the human airway. Porcine gland tissue was more sensitive to PAR2-AP, and this response was dependent on Ca(2+ and anion secretion. When the mouse trachea were exposed to PAR2-AP, large amounts of secretion were observed in both wild type and ΔF508 cystic fibrosis transmembrane conductance regulator mutant mice but there is no secretion from PAR-2 knock out mice. In conclusion, PAR2-AP is an agonist for mucus secretion from the airway gland that is Ca(2+-dependent and cystic fibrosis transmembrane conductance regulator-independent.

  17. The 'Secret' of success part 1.

    Science.gov (United States)

    Busby, Mike

    2011-03-01

    Practice success is defined across the four'dimensions' of oral health, patient satisfaction, job satisfaction and financial profit. It is suggested that the 'secret' of success in dental practice is to make patient (customer) satisfaction the primary focus. Not a very earth shattering or surprising'secret' perhaps! This is hardly a new idea, and not a concept restricted to dental practice. This principle applies to all businesses. This series of articles reviews evidence from across a broad spectrum of publications: from populist business publications through to refereed scientific papers, this'secret' seems to be confirmed. The evidence for which aspects of our service are most important in achieving patient satisfaction (and therefore success) is explored. Good oral health outcomes for patients are defined as the primary purpose of dental practice and, therefore, an essential dimension of success. The link between positive patient perceptions of general care and their own oral health to practice success is explored.

  18. The 'secret' of success. Part 3.

    Science.gov (United States)

    Busby, Mike

    2011-05-01

    Practice success is defined across the four 'dimensions' of oral health, patient satisfaction, job satisfaction and financial profit. It is suggested that the 'secret' of success in dental practice is to make patient (customer) satisfaction the primary focus. Not a very earth shattering or surprising 'secret' perhaps! This is hardly a new idea, and not a concept restricted to dental practice. This principle applies to all businesses. This series of articles reviews evidence from across a broad spectrum of publications: from populist business publications through to refereed scientific papers, this 'secret' seems to be confirmed. The evidence for which aspects of our service are most important in achieving patient satisfaction (and therefore success) is explored. Good oral health outcomes for patients are defined as the primary purpose of dental practice and, therefore, an essential dimension of success. The link between positive patient perceptions of general care and his/her own oral health to practice success is explored.

  19. The 'secret' of success. Part 2.

    Science.gov (United States)

    Busby, Mike

    2011-04-01

    Practice success is defined across the four 'dimensions' of oral health, patient satisfaction, job satisfaction and financial profit. It is suggested that the 'secret' of success in dental practice is to make patient (customer) satisfaction the primary focus. Not a very earth shattering or surprising 'secret' perhaps! This is hardly a new idea, and not a concept restricted to dental practice. This principle applies to all businesses. This series of articles reviews evidence from across a broad spectrum of publications: from populist business publications through to refereed scientific papers, this 'secret' seems to be confirmed. The evidence for which aspects of our service are most important in achieving patient satisfaction (and therefore success) is explored. Good oral health outcomes for patients are defined as the primary purpose of dental practice and, therefore, an essential dimension of success. The link between positive patient perceptions of general care and their own oral health to practice success is explored.

  20. The 'secret' of success part 4.

    Science.gov (United States)

    Busby, Mike

    2011-06-01

    Practice success is defined across the four'dimensions' of oral health, patient satisfaction, job satisfaction and financial profit. It is suggested that the'secret' of success in dental practice is to make patient (customer) satisfaction the primary focus. Not a very earth shattering or surprising 'secret' perhaps! This is hardly a new idea, and not a concept restricted to dental practice. This principle applies to all businesses. This series of articles reviews evidence from across a broad spectrum of publications: from populist business publications through to refereed scientific papers, this'secret' seems to be confirmed. The evidence for which aspects of our service are most important in achieving patient satisfaction (and therefore success) is explored. Good oral health outcomes for patients are defined as the primary purpose of dental practice and, therefore, an essential dimension of success. The link between positive patient perceptions of general care and their own oral health to practice success is explored.

  1. Standpoints and protection of business secrets

    Directory of Open Access Journals (Sweden)

    Brane Bertoncelj

    2001-06-01

    Full Text Available The human impact on an information system where data bases, containing business secretes, are stored is one of the most unreliable and unforeseeable factors. For this reason, it must not be underestimated. The results of this study indicate a correlation between behavioural intention and protection of business secretes. There is a statistically significant correlation between behavioural intention and behavioural supervision. This means that an increased level of perceived supervision over one's own behaviour is related to behavioural intention. A great majority of participants would not divulge a business secret due to internal moral factors, i.e., they possess the appropriate capabilities to determine the advantages of social moral values over personal values.

  2. Measurement of secretion in nasal lavage

    DEFF Research Database (Denmark)

    Bisgaard, H; Krogsgaard, O W; Mygind, N

    1987-01-01

    1. The amount of admixture in nasal lavage fluids was determined by addition of 99mTc labelled albumin, providing a correction factor for measurements of cellular material and humoral substances in nasal lavage return as well as a quantitative measure of nasal secretions. 2. Albumin was chosen...... secretion to be carried out on the whole sample of lavage fluid, thereby avoiding the necessity of complete admixture between marker and lavage fluid which would be pertinent to marker molecules measured chemically. The radiation from a nasal lavage is minimal and the procedure is fully acceptable...... of the nose, yet not the oropharynx. 5. A dose related increase in nasal secretion harvested by the nasal lavage in 10 persons challenged with histamine chloride could be demonstrated by this technique. 6. It is concluded that the use of 99mTc-albumin in a nasal washing provides a safe, simple and quick...

  3. Apical secretion of apolipoproteins from enterocytes

    DEFF Research Database (Denmark)

    Danielsen, E M; Hansen, Gert Helge; Poulsen, Mona Dam

    1993-01-01

    Synthesis and secretion of apolipoproteins in pig small intestine was studied by pulse-chase labeling of jejunal segments, kept in organ culture. Apo A-1 and apo B-48 were the two major proteins released, constituting 25 and 10%, respectively, of the total amount of labeled protein in the mucosal...... in the soluble fraction, suggesting a basolateral secretion into the intercellular space, and both this accumulation and the release to the medium was prevented by culture at 20 degrees C. The specific radioactivity of apo A-1 and apo B-48 released to the medium was significantly higher than...... that enterocytes release most of their newly made free apo A-1 and a significant portion of apo B-48 by exocytosis via the brush border membrane into the intestinal lumen. Fat absorption reduced apolipoprotein secretion to the medium and induced the formation of chylomicrons, containing apo A-1 at their surface...

  4. Hiding secret data into a carrier image

    Directory of Open Access Journals (Sweden)

    Ovidiu COSMA

    2012-06-01

    Full Text Available The object of steganography is embedding hidden information in an appropriate multimedia carrier, e.g., image, audio, or video. There are several known methods of solving this problem, which operate either in the space domain or in the frequency domain, and are distinguished by the following characteristics: payload, robustness and strength. The payload is the amount of secret data that can be embedded in the carrier without inducing suspicious artefacts, robustness indicates the degree in which the secret data is affected by the normal processing of the carrier e.g., compression, and the strength indicate how easy the presence of hidden data can be detected by steganalysis techniques. This paper presents a new method of hiding secret data into a digital image compressed by a technique based on the Discrete Wavelet Transform (DWT [2] and the Set Partitioning In Hierarchical Trees (SPIHT subband coding algorithm [6]. The proposed method admits huge payloads and has considerable strength.

  5. Pancreatic exocrine secretion in atomic bomb survivors

    International Nuclear Information System (INIS)

    Hiraoka, Masataka; Kawanishi, Masahiro; Ohtaki, Megu

    1989-01-01

    This study was designed to examine the effect of A-bombing on pancreatic exocrine secretion in 6 A-bomb survivors (an average age of 57 years) and the age- and sex-matched non-exposed 6 persons (an average age of 58 years). Six A-bomb survivors consisted of: three who had been directly exposed to A-bombing, one who had entered the city within 3 days after bombing, one who had worked in caring for A-bomb survivors, and one who had later entered the city. Caerulein-Secretin test revealed no significant difference in the total secretion of lipase, maximum bicarbonate, amylase output, or lipase output between the exposed and non-exposed groups. The concentration of lipase ten min after stimulation was significantly decreased in the exposed group than the control group. This suggests that radiation may be responsible for abnormality in the ability of pancreatic exocrine secretion. (N.K.)

  6. Role of transient receptor potential melastatin-like subtype 5 channel in insulin secretion from rat β-cells.

    Science.gov (United States)

    Krishnan, Kalaiselvan; Ma, Zuheng; Björklund, Anneli; Islam, Md Shahidul

    2014-05-01

    Several studies have reported that the transient receptor potential melastatin-like subtype 5 (TRPM5) channel, a Ca(2+)-activated monovalent cation channel, is involved in the stimulus-secretion coupling in the mouse pancreatic β-cells. We have studied the role of the TRPM5 channel in regulating insulin secretion and cytoplasmic free Ca(2+) concentration ([Ca(2+)](i)) in the rat β-cells by using triphenylphosphine oxide, a selective inhibitor of the channel. Insulin secretion from islets from Sprague-Dawley rats was measured in batch incubations. Cytoplasmic free Ca(2+) concentration was measured from single β-cells by fura-2-based microfluorometry. Triphenylphosphine oxide did not alter insulin secretion and [Ca(2+)](i) response triggered by KCl or fructose. It inhibited insulin secretion in response to glucose, L-arginine, and glucagon-like peptide 1. It also inhibited glucose-induced insulin secretion by mechanisms that are independent of the adenosine triphosphate-sensitive potassium channels and [Ca(2+)](i) increase. Our results suggest that in the rat islets, TRPM5 is involved in mediating insulin secretion by glucose and l-arginine and in potentiating the glucose-induced insulin secretion by glucagon-like peptide 1.

  7. Sodium arsenite impairs insulin secretion and transcription in pancreatic β-cells

    International Nuclear Information System (INIS)

    Diaz-Villasenor, Andrea; Sanchez-Soto, M. Carmen; Cebrian, Mariano E.; Ostrosky-Wegman, Patricia; Hiriart, Marcia

    2006-01-01

    Human studies have shown that chronic inorganic arsenic (iAs) exposure is associated with a high prevalence and incidence of type 2 diabetes. However, the mechanism(s) underlying this effect are not well understood, and practically, there is no information available on the effects of arsenic on pancreatic β-cells functions. Thus, since insulin secreted by the pancreas plays a crucial role in maintaining glucose homeostasis, our aim was to determine if sodium arsenite impairs insulin secretion and mRNA expression in single adult rat pancreatic β-cells. Cells were treated with 0.5, 1, 2, 5 and 10 μM sodium arsenite and incubated for 72 and 144 h. The highest dose tested (10 μM) decreased β-cell viability, by 33% and 83%, respectively. Insulin secretion and mRNA expression were evaluated in the presence of 1 and 5 μM sodium arsenite. Basal insulin secretion, in 5.6 mM glucose, was not significantly affected by 1 or 5 μM treatment for 72 h, but basal secretion was reduced when cells were exposed to 5 μM sodium arsenite for 144 h. On the other hand, insulin secretion in response to 15.6 mM glucose decreased with sodium arsenite in a dose-dependent manner in such a way that cells were no longer able to distinguish between different glucose concentrations. We also showed a significant decrease in insulin mRNA expression of cells exposed to 5 μM sodium arsenite during 72 h. Our data suggest that arsenic may contribute to the development of diabetes mellitus by impairing pancreatic β-cell functions, particularly insulin synthesis and secretion

  8. Proton pump inhibitors exert anti-allergic effects by reducing TCTP secretion.

    Directory of Open Access Journals (Sweden)

    Sunghee Choi

    Full Text Available BACKGROUND: Extracellular translationally controlled tumor protein (TCTP is known to play a role in human allergic responses. TCTP has been identified outside of macrophages, in activated mononuclear cells, and in biological fluids from allergic patients. Even TCTP devoid of signal sequences, is secreted to extracellular environment by an yet undefined mechanism. This study is aimed at understanding the mechanism of TCTP release and its regulation. A secondary goal is to see if inhibitors of TCTP release can serve as potential anti-allergic asthmatic drugs. METHODOLOGY/PRINCIPAL FINDINGS: Using Western blotting assay in HEK293 and U937 cells, we found that TCTP secretion is reduced by omeprazole and pantoprazole, both of which are proton pump inhibitors. We then transfected HEK293 cells with proton pump expression vectors to search for the effects of exogeneously overexpressed H(+/K(+-ATPase on the TCTP secretion. Based on these in vitro data we checked the in vivo effects of pantoprazole in a murine model of ovalbumin-induced allergy. Omeprazole and pantoprazole reduced TCTP secretion from HEK293 and U937 cells in a concentration-dependent fashion and the secretion of TCTP from HEK293 cells increased when they over-expressed H(+/K(+-ATPase. In a murine model of ovalbumin-induced allergy, pretreatment with pantoprazole reduced infiltration of inflammatory cells, increased goblet cells, and increased TCTP secretion induced by OVA challenge. CONCLUSION: Since Omeprazole and pantoprazole decrease the secretion of TCTP which is associated with the development of allergic reaction, they may have the potential to serve as anti-allergic (asthmatic drugs.

  9. Secrets Pages in DR’s Playbook

    DEFF Research Database (Denmark)

    Nielsen, Jakob Isak

    According to former Head of Drama at DR, Ingolf Gabold, one of the “great” and “strange” secrets subtending the success of DR’s TV series is the extremely deliberate work with audiovisual style (Gabold in Nielsen 2012). Here - as elsewhere - Gabold highlights the so-called “paramount-meeting” and......According to former Head of Drama at DR, Ingolf Gabold, one of the “great” and “strange” secrets subtending the success of DR’s TV series is the extremely deliberate work with audiovisual style (Gabold in Nielsen 2012). Here - as elsewhere - Gabold highlights the so-called “paramount...

  10. Antitumoral Potential of Tunisian Snake Venoms Secreted Phospholipases A2

    Directory of Open Access Journals (Sweden)

    Raoudha Zouari-Kessentini

    2013-01-01

    Full Text Available Phospholipases type A2 (PLA2s are the most abundant proteins found in Viperidae snake venom. They are quite fascinating from both a biological and structural point of view. Despite similarity in their structures and common catalytic properties, they exhibit a wide spectrum of pharmacological activities. Besides being hydrolases, secreted phospholipases A2 (sPLA2 are an important group of toxins, whose action at the molecular level is still a matter of debate. These proteins can display toxic effects by different mechanisms. In addition to neurotoxicity, myotoxicity, hemolytic activity, antibacterial, anticoagulant, and antiplatelet effects, some venom PLA2s show antitumor and antiangiogenic activities by mechanisms independent of their enzymatic activity. This paper aims to discuss original finding against anti-tumor and anti-angiogenic activities of sPLA2 isolated from Tunisian vipers: Cerastes cerastes and Macrovipera lebetina, representing new tools to target specific integrins, mainly, and integrins.

  11. Simultaneous detection of gastric acid and histamine release to unravel the regulation of acid secretion from the guinea pig stomach.

    Science.gov (United States)

    Bitziou, Eleni; Patel, Bhavik Anil

    2012-08-01

    Gastric acid secretion is regulated by three primary components that activate the parietal cell: histamine, gastrin, and acetylcholine (ACh). Although much is known about these regulatory components individually, little is known on the interplay of these multiple activators and the degree of regulation they pose on the gastric acid secretion mechanism. We utilized a novel dual-sensing approach, where an iridium oxide sensor was used to monitor pH and a boron-doped diamond electrode was used for the detection of histamine from in vitro guinea pig stomach mucosal sections. Under basal conditions, gastrin was shown to be the main regulatory component of the total acid secretion and directly activated the parietal cell rather than by mediating gastric acid secretion through the release of histamine from the enterochromaffin-like cell, although both pathways were active. Under stimulated conditions with ACh, the gastrin and histamine components of the total acid secretion were not altered compared with levels observed under basal conditions, suggestive that ACh had no direct effect on the enterochromaffin-like cell and G cell. These data identify a new unique approach to investigate the regulation pathways active during acid secretion and the degree that they are utilized to drive total gastric acid secretion. The findings of this study will enhance our understanding on how these signaling mechanisms vary under pathophysiology or therapeutic management.

  12. "Nonclassical" secretion of annexin A2 to the lumenal side of the enterocyte brush border membrane

    DEFF Research Database (Denmark)

    Danielsen, E Michael; van Deurs, Bo; Hansen, Gert H

    2003-01-01

    side of the microvilli, showing an apical secretion by a "nonclassical" mechanism. In addition, annexin A2 was associated with surface-connected, deep apical tubules in the apical terminal web region and with an underlying pleiomorphic, tubulo-vesicular compartment (subapical compartment...

  13. Sensing of Bacterial Type IV Secretion via the Unfolded Protein Response

    NARCIS (Netherlands)

    de Jong, Maarten F.; Starr, Tregei; Winter, Maria G.; den Hartigh, Andreas B.; Child, Robert; Knodler, Leigh A.; van Dijl, Jan Maarten; Celli, Jean; Tsolis, Renee M.

    2013-01-01

    Host cytokine responses to Brucella abortus infection are elicited predominantly by the deployment of a type IV secretion system (T4SS). However, the mechanism by which the T4SS elicits inflammation remains unknown. Here we show that translocation of the T4SS substrate VceC into host cells induces

  14. Involvement of nitric oxide in neuroglycopenia-induced insulin and glucagon secretion in the mouse

    NARCIS (Netherlands)

    Ahrén, Bo; Karlsson, Sven; Scheurink, Anton J.W.; Steffens, Anton B.

    1995-01-01

    Neuroglycopenia induced by administration of 2-deoxy-D-glucose is known to stimulate the secretion of both insulin and glucagon in mice by a mechanism that is dependent on neural activity. In the present study, we examined whether the neurotransmitter nitric oxide (NO) is involved in this process.

  15. A Genome-Wide Association Study of IVGTT-Based Measures of First Phase Insulin Secretion Refines the Underlying Physiology of Type 2 Diabetes Variants

    DEFF Research Database (Denmark)

    Wood, Andrew R; Jonsson, Anna; Jackson, Anne U

    2017-01-01

    Understanding the physiological mechanisms by which common variants predispose to type 2 diabetes requires large studies with detailed measures of insulin secretion and sensitivity. Here we performed the largest genome-wide association study of first-phase insulin secretion, as measured by intrav...

  16. Factors influencing insulin secretion from encapsulated islets

    NARCIS (Netherlands)

    de Haan, BJ; Faas, MM; de Vos, P

    2003-01-01

    Adequate regulation of glucose levels by a microencapsulated pancreatic islet graft requires a minute-to-minute regulation of blood glucose. To design such a transplant, it is mandatory to have sufficient insight in factors influencing the kinetics of insulin secretion by encapsulated islets. The

  17. The Best kept Secrets In Government.

    Science.gov (United States)

    1996-09-01

    workers. 113 The Best Kept Secrets In Government • Sweatshops are under attack. More than 50 manufacturing firms across the country have com...Employment and Training Administration Eradicating Sweatshops Initiative Fax on Demand Federal Employees’ Compensation Reengineering Project Team

  18. Employees, Trade Secrets and Restrictive Covenants

    NARCIS (Netherlands)

    Kamperman Sanders, Anselm; Heath, C.

    2017-01-01

    The book covers the protection of trade secrets and the law on post-contractual non-compete clauses (restrictive covenants) in an employment context. The topic is approached on an international and comparative level (chapters 1–3 and 10), and by way of country reports covering several European and

  19. The Secret Sex Lives of Rotifers Sex

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 5; Issue 12. The Secret Sex Lives of Rotifers Sex - sex and Cannibalism. T Ramakrishna Rao. General Article Volume 5 Issue 12 December 2000 pp 41-47. Fulltext. Click here to view fulltext PDF. Permanent link:

  20. Trade Secrets for Crafting a Conceptual Article.

    Science.gov (United States)

    Salamone, Paul R.

    1993-01-01

    The author clarifies the distinction between a sound conceptual article and a literature review, outlines the creative process as it applies to written work, and provides "trade secrets" for novice writers on how to enhance their literary creativity and how to confront and solve writing problems. (Author/SR)

  1. Surfactant secretion and clearance in the newborn

    International Nuclear Information System (INIS)

    Stevens, P.A.; Wright, J.R.; Clements, J.A.

    1989-01-01

    Pregnant rabbits (30 days) were injected intravenously with [3H]choline 8 h before delivery. The fetuses were delivered, and lung lavage and lamellar body phospholipids (PL) were analyzed. Some newborns also received radioactively labeled surfactant intratracheally on delivery and were permitted to breathe. With time, intratracheal label decreased in lavage and appeared in the lamellar body fraction, and intravenous label accumulated in both pools. Using a tracer analysis for non-steady state, we calculated surfactant secretion and clearance rates for the newborn period. Before birth, both rates rose slightly from 1.8 micrograms PL.g body wt-1.h-1 at 6 h before birth to 7.3 at birth. Immediately after birth, secretion rate rose to 37.7 micrograms PL.g body wt-1.h-1. Between 1.5 and 2 h after birth it fell to a minimum of 1.8 micrograms PL.g body wt-1.h-1 and then rose slowly to 6.0 at 12 h. After birth, clearance rate increased less than secretion rate (maximum 24.7 micrograms PL.g body wt-1.h-1 shortly after birth) then followed the same pattern but did not balance secretion rate in the 1st day

  2. Gastric Acid Secretion, Mucus Concentration and Ulceration ...

    African Journals Online (AJOL)

    This study was carried out to evaluate the effect of consumption (ingestion) of Cannabis sativa on the gastrointestinal tract using mucus concentration, acid secretion and ulceration in animal (rats) model as indices. Three groups of six (6) rats each were used. The control group were fed on rat chow only while another group ...

  3. Secret Shopping as User Experience Assessment Tool

    Science.gov (United States)

    Boyce, Crystal M.

    2015-01-01

    Secret shopping is a form of unobtrusive evaluation that can be accomplished with minimal effort, but still produce rich results. With as few as 11 shoppers, the author was able to identify trends in user satisfaction with services provided across two entry-level desks at Illinois Wesleyan University's The Ames Library. The focus of this secret…

  4. Experimental Study on Gastric Juice Secretion by ...

    African Journals Online (AJOL)

    管理平台

    2012-05-29

    May 29, 2012 ... reduced (P < 0.05) when acupuncture at zusanli was applied after treatment with cimetidine. Therefore, our study shows that when electroacupuncture at zusanli is applied, the gastric electrical frequency increased and gastric electrical amplitude reduced, while the flux of gastric juice secretion increased.

  5. Parathyroid hormone secretion in chronic renal failure

    DEFF Research Database (Denmark)

    Madsen, J C; Rasmussen, A Q; Ladefoged, S D

    1996-01-01

    The aim of study was to introduce and evaluate a method for quantifying the parathyroid hormone (PTH) secretion during hemodialysis in secondary hyperparathyroidism due to end-stage renal failure. We developed a method suitable for inducing sequential hypocalcemia and hypercalcemia during...

  6. Secretion Of Methionine By Microorganisms Associated With ...

    African Journals Online (AJOL)

    methionine were secreted after 96 hours and 72 hours respectively by the lactobacilli and Leuconostoc sp. Since lactic acid bacteria are micro-aerophilic, it is suggested that lactic acid bacteria (the two lactobacilli and Leuconostoc sp.), which are the major organisms involved in cassava fermentation for garri production, ...

  7. Moderate expression of SEC16 increases protein secretion by Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Bao, Jichen; Huang, Mingtao; Petranovic, Dina

    2017-01-01

    in yeast, by moderately overexpressing SEC16, which is involved in protein translocation from the endoplasmic reticulum to the Golgi apparatus. The moderate overexpression of SEC16 increased α-amylase secretion by generating more endoplasmic reticulum exit sites. The production of reactive oxygen species...... were observed. Finally, the moderate overexpression of SEC16 was shown to improve the secretion of two other recombinant proteins, Trichoderma reesei endoglucanase I and Rhizopus oryzae glucan-1,4-α-glucosidase, indicating that this mechanism is of general relevance....

  8. Analysis of the surface, secreted, and intracellular proteome of Propionibacterium acnes

    Directory of Open Access Journals (Sweden)

    Yang Yu

    2015-12-01

    Full Text Available Propionibacterium acnes, plays an important role in acne vulgaris and other diseases. However, understanding of the exact mechanisms of P. acnes pathogenesis is limited. Few studies have investigated its proteome, which is essential for vaccine development. Here, we comprehensively investigate the proteome of P. acnes strain ATCC 6919, including secreted, cell wall, membrane, and cytosolic fractions in three types of growth media. A total of 531 proteins were quantified using an Orbitrap mass spectrometer and bioinformatically categorized for localization and function. Several, including PPA1939, a highly expressed surface and secreted protein, were identified as potential vaccine candidates.

  9. Bidirectional regulation of bakuchiol, an estrogenic-like compound, on catecholamine secretion

    Energy Technology Data Exchange (ETDEWEB)

    Mao, Haoping; Wang, Hong; Ma, Shangwei; Xu, Yantong; Zhang, Han; Wang, Yuefei [Tianjin State Key Laboratory of Modern Chinese Medicine, Key Laboratory of Pharmacology of Traditional Chinese Medicine Formulae (China); Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin (China); Niu, Zichang [First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin (China); Fan, Guanwei; Zhu, Yan [Tianjin State Key Laboratory of Modern Chinese Medicine, Key Laboratory of Pharmacology of Traditional Chinese Medicine Formulae (China); Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin (China); Gao, Xiu Mei, E-mail: gaoxiumei@tjutcm.edu.cn [Tianjin State Key Laboratory of Modern Chinese Medicine, Key Laboratory of Pharmacology of Traditional Chinese Medicine Formulae (China); Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin (China)

    2014-01-01

    Excess or deficiency of catecholamine (CA) secretion was related with several diseases. Recently, estrogen and phytoestrogens were reported to regulate the activity of CA system. Bakuchiol is a phytoestrogen isolated from the seeds of Psoralea corylifolia L. (Leguminosae) which has been used in Traditional Chinese medicine as a tonic or aphrodisiac. In the present study, bovine adrenal medullary cells were employed to investigate the effects and mechanisms of bakuchiol on the regulation of CA secretion. Further, its anti-depressant like and anti-stress effects were evaluated by using behavioral despair and chronic immobilization stress models. Our results indicated that bakuchiol showed bidirectional regulation on CA secretion. It stimulated basal CA secretion in a concentration dependent manner (p < 0.01), while it reduced 300 μM acetylcholine (ACh) (p < 0.01), 100 μM veratridine (Ver) (p < 0.01) and 56 mM K{sup +} (p < 0.05) induced CA secretion, respectively. We also found that the stimulation of basal CA secretion by bakuchiol may act through estrogen-like effect and the JNK pathway in an extra-cellular calcium independent manner. Further, bakuchiol elevated tyrosine hydroxylase Ser40 and Ser31 phosphorylation (p < 0.01) through the PKA and ERK1/2 pathways, respectively. Bakuchiol inhibited ACh, Ver and 56 mM K{sup +} induced CA secretion was related with reduction of intracellular calcium rise. In vivo experiments, we found that bakuchiol significantly reduced immobilization time in behavioral despair mouse (p < 0.05 or 0.01), and plasma epinephrine (E) and norepinephrine (NE) levels in chronic immobilization stress (p < 0.05). Overall, these results present a bidirectional regulation of bakuchiol on CA secretion which indicated that bakuchiol may exert anti-stress and the potential anti-depressant-like effects. - Highlights: • Bakuchiol stimulated basal catecholamine secretion. • Bakuchiol inhibited various secretagogues induced catecholamine secretion

  10. Extra! Extracellular Effector Delivery into Host Cells via the Type 3 Secretion System

    OpenAIRE

    Kendall, Melissa M.

    2017-01-01

    ABSTRACT The type three secretion system (T3SS) is critical for the virulence of diverse bacterial pathogens. Pathogens use the T3SS to deliver effector proteins into host cells and manipulate host signaling pathways. The prevailing mechanism is that effectors translocate from inside the T3SS directly into the host cell. Recent studies reveal an alternative mechanism of effector translocation, in which an effector protein located outside the bacterial cell relies on the T3SS for delivery into...

  11. [Mass spectrometry identification of secreted proteins from Bacillus firmus and analysis of its secretive sequences].

    Science.gov (United States)

    Liu, Sun; Song, Xiaoling; Huang, Jie

    2011-07-01

    Bacillus firmus was a common probiotics bacteria in nature and widely used in the shrimp aquaculture. In order to construct expression vectors for secretive proteins, we identified several major secretive proteins of Bacillus firmus by mass spectrometry and analyzed their gene sequences to find signal peptide sequences. The secreted proteins of Bacillus firmus were extracted and separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The 3 highly expressed protein bands in the SDS-PAGE were identified by mass spectrometry Matrix Assisted Laser Desorption Ionization (MALDI)-Time of Flight (TOF)/Time of Flight (TOF) and the sequences were downloaded from National Center for Biotechnology Information (NCBI) database. Then Polymerase Chain Reaction (PCR) primers were designed according to the downloaded sequences and specific DNA bands were amplified sequenced and bioinformatics analyzed. The proteins were identified as the putative chitinase, enterotoxin A and protein BCG9842 of Bacillus firmus. Three signal peptides were conformed by using the online software SignaIP 3.0, namely bf-43, bf-37 and bf-16. The cellular localization of the secreted sequences were analyzed by PSORT. And we found that bf-43 located in the outer membrane of cells, bf-37 and bf-16 located in the extracellular cell. 3 major secreted proteins of Bacillus firmus have been identified. 3 possible signal peptides were obtained and will be useful for the construction of expression vectors for secretive proteins.

  12. Long-term outcomes of surgery and radiotherapy for secreting and non-secreting pituitary adenoma

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Mi Young; Kim, Jin Hee; Oh, Young Kee; Kim, El [Dongsan Medical Center, Keimyung University School of Medicine, Daegu (Korea, Republic of)

    2016-06-15

    To investigate treatment outcome and long term complication after surgery and radiotherapy (RT) for pituitary adenoma. From 1990 to 2009, 73 patients with surgery and RT for pituitary adenoma were analyzed in this study. Median age was 51 years (range, 25 to 71 years). Median tumor size was 3 cm (range, 1 to 5 cm) with suprasellar (n = 21), cavernous sinus extension (n = 14) or both (n = 5). Hormone secreting tumor was diagnosed in 29 patients; 16 patients with prolactin, 12 patients with growth hormone, and 1 patient with adrenocorticotrophic hormone. Impairment of visual acuity or visual field was presented in 33 patients at first diagnosis. Most patients (n = 64) received RT as postoperative adjuvant setting. Median RT dose was 45 Gy (range, 45 to 59.4 Gy). Median follow-up duration was 8 years (range, 3 to 22 years). In secreting tumors, hormone normalization rate was 55% (16 of 29 patients). For 25 patients with evaluable visual field and visual acuity test, 21 patients (84%) showed improvement of visual disturbance after treatment. The 10-year tumor control rate for non-secreting and secreting adenoma was 100% and 58%, respectively (p < 0.001). Progression free survival rate at 10 years was 98%. Only 1 patient experienced endocrinological recurrence. Following surgery, 60% (n = 44) suffered from pituitary function deficit. Late complication associated with RT was only 1 patient, who developed cataract. Surgery and RT are very effective and safe in hormonal and tumor growth control for secreting and non-secreting pituitary adenoma.

  13. Synergistic mucus secretion by histamine and IL-4 through TMEM16A in airway epithelium.

    Science.gov (United States)

    Kang, Ju Wan; Lee, Yong Hyuk; Kang, Min Jeong; Lee, Hyun Jae; Oh, Ryung; Min, Hyun Jin; Namkung, Wan; Choi, Jae Young; Lee, Sang Nam; Kim, Chang-Hoon; Yoon, Joo-Heon; Cho, Hyung-Ju

    2017-09-01

    Histamine is an important mediator of allergic reactions, and mucus hypersecretion is a major allergic symptom. However, the direct effect of histamine on mucus secretion from airway mucosal epithelia has not been clearly demonstrated. TMEM16A is a Ca 2+ -activated chloride channel, and it is closely related to fluid secretion in airway mucosal epithelia. We investigated whether histamine directly induces fluid secretion from epithelial cells or submucosal glands (SMG) and mechanisms related, therewith, in allergic airway diseases. In pig airway tissues from the nose or trachea, histamine was a potent secretagogue that directly induced strong responses. However, gland secretion from human nasal tissue was not induced by histamine, even in allergic rhinitis patients. Histamine type 1 receptor (H1R) and histamine type 2 receptor (H2R) were not noted in SMG by in situ hybridization. Cultured primary human nasal epithelial (NHE) cells were used for the measurement of short-circuit current changes with the Ussing chamber. Histamine-induced slight responses of anion secretions under normal conditions. The response was enhanced by IL-4 stimulation through TMEM16A, which might be related to fluid hypersecretion in allergic rhinitis. Pretreatment with IL-4 augmented the histamine response that was suppressed by a TMEM16A inhibitor. TMEM16A expression was enhanced by 24-h treatment of IL-4 in human nasal epithelial cells. The expression of TMEM16A was significantly elevated in an allergic rhinitis group, compared with a control group. We elucidated histamine-induced fluid secretions in synergy with IL-4 through TMEM16A in the human airway epithelium. In addition, we observed species differences between pigs and humans in terms of gland secretion of histamine. Copyright © 2017 the American Physiological Society.

  14. Plant Fe status affects the composition of siderophore-secreting microbes in the rhizosphere.

    Science.gov (United States)

    Jin, Chong Wei; Li, Gui Xin; Yu, Xue Hui; Zheng, Shao Jian; Zheng, Shao Jiang

    2010-05-01

    Soil microbes have been demonstrated to play an important role in favouring plant iron (Fe) uptake under Fe-limiting conditions. However, the mechanisms involved are still unclear. This present study reported the effects of plant Fe status on the composition of siderophore-secreting microbes in the rhizosphere, and their potential function in improving plant Fe nutrition. An Fe-efficient plant, red clover (Trifolium pratense 'Kenland') was cultured in a calcareous soil to obtain rhizosphere soils with (Fe-sufficient) or without (Fe-stressed) foliar FeEDTA spraying. The siderophore-producing ability of rhizospheric microbes was measured. The bioavailability of the siderophore-solubilized Fe from iron oxides/hydroxides was tested in hydroponic culture. In rhizosphere soil, the number of microbes that secreted siderophores quickly was more in the Fe-stressed treatment than in the Fe-sufficient one, while the number of microbes that did not secret siderophores was the opposite. A significantly higher concentration of phenolics was detected in the rhizosphere soil of Fe-stressed plants. Moreover, after the soil was incubated with phenolic root exudates, the composition of the siderophore-secreting microbial community was similar with that of the rhizosphere of Fe-stressed plant. Additionally, the siderophores produced by a rhizospheric microbe isolated from the Fe-stressed treatment can well solubilize iron oxides/hydroxides, and the utilization of the siderophore-solubilized Fe by plant was even more efficient than EDTA-Fe. Iron-deficiency stress of red clover would alter the composition of siderophore-secreting microbes in the rhizosphere, which is probably due to the phenolics secretion of the root, and may in turn help to improve the solubility of Fe in soils and plant Fe nutrition via elevated microbial siderophore secretion.

  15. Selective condensation drives partitioning and sequential secretion of cyst wall proteins in differentiating Giardia lamblia.

    Directory of Open Access Journals (Sweden)

    Christian Konrad

    2010-04-01

    Full Text Available Controlled secretion of a protective extracellular matrix is required for transmission of the infective stage of a large number of protozoan and metazoan parasites. Differentiating trophozoites of the highly minimized protozoan parasite Giardia lamblia secrete the proteinaceous portion of the cyst wall material (CWM consisting of three paralogous cyst wall proteins (CWP1-3 via organelles termed encystation-specific vesicles (ESVs. Phylogenetic and molecular data indicate that Diplomonads have lost a classical Golgi during reductive evolution. However, neogenesis of ESVs in encysting Giardia trophozoites transiently provides basic Golgi functions by accumulating presorted CWM exported from the ER for maturation. Based on this "minimal Golgi" hypothesis we predicted maturation of ESVs to a trans Golgi-like stage, which would manifest as a sorting event before regulated secretion of the CWM. Here we show that proteolytic processing of pro-CWP2 in maturing ESVs coincides with partitioning of CWM into two fractions, which are sorted and secreted sequentially with different kinetics. This novel sorting function leads to rapid assembly of a structurally defined outer cyst wall, followed by slow secretion of the remaining components. Using live cell microscopy we find direct evidence for condensed core formation in maturing ESVs. Core formation suggests that a mechanism controlled by phase transitions of the CWM from fluid to condensed and back likely drives CWM partitioning and makes sorting and sequential secretion possible. Blocking of CWP2 processing by a protease inhibitor leads to mis-sorting of a CWP2 reporter. Nevertheless, partitioning and sequential secretion of two portions of the CWM are unaffected in these cells. Although these cysts have a normal appearance they are not water resistant and therefore not infective. Our findings suggest that sequential assembly is a basic architectural principle of protective wall formation and requires

  16. Candida albicans secreted aspartyl proteinases in virulence and pathogenesis.

    Science.gov (United States)

    Naglik, Julian R; Challacombe, Stephen J; Hube, Bernhard

    2003-09-01

    Candida albicans is the most common fungal pathogen of humans and has developed an extensive repertoire of putative virulence mechanisms that allows successful colonization and infection of the host under suitable predisposing conditions. Extracellular proteolytic activity plays a central role in Candida pathogenicity and is produced by a family of 10 secreted aspartyl proteinases (Sap proteins). Although the consequences of proteinase secretion during human infections is not precisely known, in vitro, animal, and human studies have implicated the proteinases in C. albicans virulence in one of the following seven ways: (i) correlation between Sap production in vitro and Candida virulence, (ii) degradation of human proteins and structural analysis in determining Sap substrate specificity, (iii) association of Sap production with other virulence processes of C. albicans, (iv) Sap protein production and Sap immune responses in animal and human infections, (v) SAP gene expression during Candida infections, (vi) modulation of C. albicans virulence by aspartyl proteinase inhibitors, and (vii) the use of SAP-disrupted mutants to analyze C. albicans virulence. Sap proteins fulfill a number of specialized functions during the infective process, which include the simple role of digesting molecules for nutrient acquisition, digesting or distorting host cell membranes to facilitate adhesion and tissue invasion, and digesting cells and molecules of the host immune system to avoid or resist antimicrobial attack by the host. We have critically discussed the data relevant to each of these seven criteria, with specific emphasis on how this proteinase family could contribute to Candida virulence and pathogenesis.

  17. Secreted Phospholipases A₂ from Animal Venoms in Pain and Analgesia.

    Science.gov (United States)

    Zambelli, Vanessa O; Picolo, Gisele; Fernandes, Carlos A H; Fontes, Marcos R M; Cury, Yara

    2017-12-19

    Animal venoms comprise a complex mixture of components that affect several biological systems. Based on the high selectivity for their molecular targets, these components are also a rich source of potential therapeutic agents. Among the main components of animal venoms are the secreted phospholipases A₂ (sPLA₂s). These PLA₂ belong to distinct PLA₂s groups. For example, snake venom sPLA₂s from Elapidae and Viperidae families, the most important families when considering envenomation, belong, respectively, to the IA and IIA/IIB groups, whereas bee venom PLA₂ belongs to group III of sPLA₂s. It is well known that PLA₂, due to its hydrolytic activity on phospholipids, takes part in many pathophysiological processes, including inflammation and pain. Therefore, secreted PLA₂s obtained from animal venoms have been widely used as tools to (a) modulate inflammation and pain, uncovering molecular targets that are implicated in the control of inflammatory (including painful) and neurodegenerative diseases; (b) shed light on the pathophysiology of inflammation and pain observed in human envenomation by poisonous animals; and, (c) characterize molecular mechanisms involved in inflammatory diseases. The present review summarizes the knowledge on the nociceptive and antinociceptive actions of sPLA₂s from animal venoms, particularly snake venoms.

  18. Melanocyte-secreted fibromodulin promotes an angiogenic microenvironment.

    Science.gov (United States)

    Adini, Irit; Ghosh, Kaustabh; Adini, Avner; Chi, Zai-Long; Yoshimura, Takeru; Benny, Ofra; Connor, Kip M; Rogers, Michael S; Bazinet, Lauren; Birsner, Amy E; Bielenberg, Diane R; D'Amato, Robert J

    2014-01-01

    Studies have established that pigmentation can provide strong, protective effects against certain human diseases. For example, angiogenesis-dependent diseases such as wet age-related macular degeneration and infantile hemangioma are more common in light-skinned individuals of mixed European descent than in African-Americans. Here we found that melanocytes from light-skinned humans and albino mice secrete high levels of fibromodulin (FMOD), which we determined to be a potent angiogenic factor. FMOD treatment stimulated angiogenesis in numerous in vivo systems, including laser-induced choroidal neovascularization, growth factor-induced corneal neovascularization, wound healing, and Matrigel plug assays. Additionally, FMOD enhanced vascular sprouting during normal retinal development. Deletion of Fmod in albino mice resulted in a marked reduction in the amount of neovascularization induced by retinal vein occlusion, corneal growth factor pellets, and Matrigel plugs. Our data implicate the melanocyte-secreted factor FMOD as a key regulator of angiogenesis and suggest an underlying mechanism for epidemiological differences between light-skinned individuals of mixed European descent and African-Americans. Furthermore, inhibition of FMOD in humans has potential as a therapeutic strategy for treating angiogenesis-dependent diseases.

  19. Benefits of interventions for respiratory secretion management in adult palliative care patients-a systematic review.

    Science.gov (United States)

    Arcuri, Juliano Ferreira; Abarshi, Ebun; Preston, Nancy J; Brine, Jenny; Pires Di Lorenzo, Valéria Amorim

    2016-08-09

    Respiratory secretions impact negatively on palliative patients. Unfortunately, a gold standard therapy is not yet available. The purpose of this study was to identify which interventions are in use to control respiratory secretions in patients with chronic disease with a poor prognosis and verify their effects on outcomes relevant for palliative care patients. A systematic review of the literature with narrative summary was conducted. We searched eight electronic databases in April (6th), 2016. Citation-tracking and reference list searches were conducted. We included randomized controlled trials, crossover trials, observational and qualitative studies regarding interventions for respiratory secretion management in adult patients with chronic diseases that met inclusion criteria indicating short prognosis. Six randomized controlled trials, 11 observational studies, ten crossover trials and one qualitative study were found. Interventions included mechanical insufflation-exsufflation (MIE), expiratory muscle training, manually-assisted cough, tracheotomy, chest physiotherapy, suctioning, air stacking, electrical stimulation of abdominal muscles, nebulized saline, positive expiratory pressure masks, percussive ventilation, high frequency chest wall oscillations. The interventions with most promising benefits to patients in palliative care were manually-assisted cough and mechanical insufflation-exsufflation to promote expectoration and percussive ventilation to improve mucous clearance. Therapies, such as manually assisted cough, mechanical insufflation-exsufflation and percussive ventilation, which aim to deal with respiratory secretion, were the most promising treatment for use in palliative care for specific diseases. Nevertheless, the evidence still needs to improve in order to identify which treatment is the best.

  20. Biliary cholesterol secretion : More than a simple ABC

    NARCIS (Netherlands)

    Dikkers, Arne; Tietge, Uwe J. F.

    2010-01-01

    Biliary cholesterol secretion is a process important for 2 major disease complexes, atherosclerotic cardiovascular disease and cholesterol gallstone disease With respect to cardiovascular disease, biliary cholesterol secretion is regarded as the final step for the elimination of cholesterol

  1. Ranitidine has no influence on tubular creatinine secretion

    NARCIS (Netherlands)

    van den Berg, J. G.; Koopman, M. G.; Arisz, L.

    1996-01-01

    Oral cimetidine competitively inhibits tubular secretion of creatinine. We investigated the potential of oral ranitidine, a comparable H2-receptor antagonist, to block tubular creatinine secretion. In 10 healthy subjects, clearances of inulin and endogenous creatinine were simultaneously measured

  2. A thyrotropin‑secreting macroadenoma with positive growth ...

    African Journals Online (AJOL)

    A thyrotropin‑secreting macroadenoma with positive growth hormone and prolactin immunostaining: A case report and literature review. ... thyroid hormone receptor resistance syndrome. Key words: Inappropriate thyroid stimulating hormone, thyrotropin‑secreting pituitary adenoma, thyroid stimulating hormone adenoma ...

  3. Energy metabolism in rat mast cells in relation to histamine secretion

    DEFF Research Database (Denmark)

    Johansen, T

    1987-01-01

    of histamine was induced by the antigen-antibody reaction, the polymeric amine compound 48/80, and the divalent ionophore A23187. 2. In presence of low concentrations of metabolic inhibitors (oligomycin or antimycin A) a linear relation between the secretion of histamine induced by all three liberators...... and the cellular ATP content at the time of cell activation was demonstrated. This may indicate a direct link between ATP and the secretory mechanism. 3. The possibility of an increased utilization of ATP during histamine secretion was explored in mast cells exposed to metabolic inhibitors. Incubation of mast...... cells with 2-deoxyglucose (2-DG) decreased the ATP content of the cells, and a long-lasting and stable level of mast cell ATP was observed. This is explained by a small decrease in the rate of ATP-synthesis by 2-DG. In 2-DG-treated cells secretion of histamine in response to compound 48...

  4. Intra- and Inter-islet Synchronization of Metabolically Driven Insulin Secretion

    DEFF Research Database (Denmark)

    Pedersen, Morten Gram; Bertram, Richard; Sherman, Arthur

    2005-01-01

    Insulin secretion from pancreatic beta-cells is pulsatile with a period of 5-10 min and is believed to be responsible for plasma insulin oscillations with similar frequency. To observe an overall oscillatory insulin pro. le it is necessary that the insulin secretion from individual beta......-cells is synchronized within islets, and that the population of islets is also synchronized. We have recently developed a model in which pulsatile insulin secretion is produced as a result of calcium-driven electrical oscillations in combination with oscillations in glycolysis. We use this model to investigate possible...... mechanisms for intra-islet and inter-islet synchronization. We show that electrical coupling is sufficient to synchronize both electrical bursting activity and metabolic oscillations. We also demonstrate that islets can synchronize by mutually entraining each other by their effects on a simple model "liver...

  5. Proteomes of the barley aleurone layer: A model system for plant signalling and protein secretion

    DEFF Research Database (Denmark)

    Finnie, Christine; Andersen, Birgit; Shahpiri, Azar

    2011-01-01

    to gibberellic acid produced by the embryo, the aleurone layer synthesises hydrolases that are secreted to the endosperm for the degradation of storage products. The barley aleurone layer can be separated from the other seed tissues and maintained in culture, allowing the study of the effect of added signalling...... molecules in an isolated system. These properties have led to its use as a model system for the study of plant signalling and germination. More recently, proteome analysis of the aleurone layer has provided new insight into this unique tissue including identification of plasma membrane proteins and targeted...... analysis of germination-related changes and the thioredoxin system. Here, analysis of intracellular and secreted proteomes reveals features of the aleurone layer system that makes it promising for investigations of plant protein secretion mechanisms....

  6. Exercise Increases Insulin Content and Basal Secretion in Pancreatic Islets in Type 1 Diabetic Mice

    Directory of Open Access Journals (Sweden)

    Han-Hung Huang

    2011-01-01

    Full Text Available Exercise appears to improve glycemic control for people with type 1 diabetes (T1D. However, the mechanism responsible for this improvement is unknown. We hypothesized that exercise has a direct effect on the insulin-producing islets. Eight-week-old mice were divided into four groups: sedentary diabetic, exercised diabetic, sedentary control, and exercised control. The exercised groups participated in voluntary wheel running for 6 weeks. When compared to the control groups, the islet density, islet diameter, and β-cell proportion per islet were significantly lower in both sedentary and exercised diabetic groups and these alterations were not improved with exercise. The total insulin content and insulin secretion were significantly lower in sedentary diabetics compared to controls. Exercise significantly improved insulin content and insulin secretion in islets in basal conditions. Thus, some improvements in exercise-induced glycemic control in T1D mice may be due to enhancement of insulin content and secretion in islets.

  7. Pituitary adenylate cyclase-activating polypeptide promotes eccrine gland sweat secretion

    DEFF Research Database (Denmark)

    Sasaki, S; Watanabe, J; Ohtaki, H

    2017-01-01

    BACKGROUND: Sweat secretion is the major function of eccrine sweat glands; when this process is disturbed (paridrosis), serious skin problems can arise. To elucidate the causes of paridrosis, an improved understanding of the regulation, mechanisms and factors underlying sweat production is required...... and several exocrine glands, the effects of PACAP on the process of eccrine sweat secretion have not been examined. OBJECTIVES: To investigate the effect of PACAP on eccrine sweat secretion. METHODS: Reverse transcriptase-polymerase chain reaction and immunostaining were used to determine the expression....... Pituitary adenylate cyclase-activating polypeptide (PACAP) exhibits pleiotropic functions that are mediated via its receptors [PACAP-specific receptor (PAC1R), vasoactive intestinal peptide (VIP) receptor type 1 (VPAC1R) and VPAC2R]. Although some studies have suggested a role for PACAP in the skin...

  8. Mining secreted proteins that function in pepper fruit development and ripening using a yeast secretion trap (YST)

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Je Min, E-mail: jemin@knu.ac.kr [Department of Plant Science, College of Agriculture and Life Sciences, Seoul National University, Seoul (Korea, Republic of); Department of Horticultural Science, Kyungpook National University, Daegu (Korea, Republic of); Lee, Sang-Jik [Biotechnology Institute, Nongwoo Bio Co, Ltd, Yeoju (Korea, Republic of); Department of Plant Biology, Cornell University, Ithaca, NY (United States); Rose, Jocelyn K.C. [Department of Plant Biology, Cornell University, Ithaca, NY (United States); Yeam, Inhwa [Department of Horticulture and Breeding, Andong National University, Andong (Korea, Republic of); Kim, Byung-Dong [Department of Plant Science, College of Agriculture and Life Sciences, Seoul National University, Seoul (Korea, Republic of)

    2014-04-18

    Highlights: • Yeast secretion trap (YST) is a valuable tool for mining secretome. • A total of 80 secreted proteins are newly identified via YST in pepper fruits. • The secreted proteins are differentially regulated during pepper development and ripening. • Transient GFP-fusion assay and in planta secretion trap can effectively validate the secretion of proteins. - Abstract: Plant cells secrete diverse sets of constitutively- and conditionally-expressed proteins under various environmental and developmental states. Secreted protein populations, or secretomes have multiple functions, including defense responses, signaling, metabolic processes, and developmental regulation. To identify genes encoding secreted proteins that function in fruit development and ripening, a yeast secretion trap (YST) screen was employed using pepper (Capsicum annuum) fruit cDNAs. The YST screen revealed 80 pepper fruit-related genes (CaPFRs) encoding secreted proteins including cell wall proteins, several of which have not been previously described. Transient GFP-fusion assay and an in planta secretion trap were used to validate the secretion of proteins encoded by selected YST clones. In addition, RNA gel blot analyses provided further insights into their expression and regulation during fruit development and ripening. Integrating our data, we conclude that the YST provides a valuable functional genomics tool for the identification of substantial numbers of novel secreted plant proteins that are associated with biological processes, including fruit development and ripening.

  9. Quantum secret sharing protocol using modulated doubly entangled photons

    International Nuclear Information System (INIS)

    Chuan, Wang; Yong, Zhang

    2009-01-01

    In this paper, we propose a quantum secret sharing protocol utilizing polarization modulated doubly entangled photon pairs. The measurement devices are constructed. By modulating the polarizations of entangled photons, the boss could encode secret information on the initial state and share the photons with different members to realize the secret sharing process. This protocol shows the security against intercept-resend attack and dishonest member cheating. The generalized quantum secret sharing protocol is also discussed. (general)

  10. EFFECT OF ADRENALECTOMY ON PROLACTIN SECRETION IN PRIMIPAROUS AND MULTIPAROUS LACTATING RATS

    Directory of Open Access Journals (Sweden)

    C. D. C. Sanches

    2018-04-01

    Full Text Available The adenohypophysis produces among other hormones prolactin, which plays an important role in reproduction, especially on the mammary glands and lactation of mammals. Prolactin is tonically controlled by tufo-infundibular dopamine, but several studies indicate that prolactin secretion is altered by the action of glucocorticoids and, therefore, is related to stress. However, the exact contribution of corticosteroids in the control of prolactin secretion is poorly understood. On the other hand, it is also known that reproductive experience can modify prolactin secretion by adenohypophysis. Thus, the present study aims to study the hormonal relationships of the hypothalamic-pituitary-adrenal axis, in particular, the glucocorticoid relationship on prolactin secretion as a function of the reproductive experience in females during lactation. The results show that reproductive experience may be a factor modifying the sensitivity of the neuroendocrine response of prolactin secretion to glucocorticoids. However, more studies are needed to understand the possible mechanisms involved, as well as possible modifications in this response as a function of the reproductive status of the females.

  11. Class I HDAC inhibition is a novel pathway for regulating astrocytic apoE secretion.

    Science.gov (United States)

    Dresselhaus, Erica; Duerr, James M; Vincent, Fabien; Sylvain, Emily K; Beyna, Mercedes; Lanyon, Lorraine F; LaChapelle, Erik; Pettersson, Martin; Bales, Kelly R; Ramaswamy, Gayathri

    2018-01-01

    Despite the important role of apolipoprotein E (apoE) secretion from astrocytes in brain lipid metabolism and the strong association of apoE4, one of the human apoE isoforms, with sporadic and late onset forms of Alzheimer's disease (AD) little is known about the regulation of astrocytic apoE. Utilizing annotated chemical libraries and a phenotypic screening strategy that measured apoE secretion from a human astrocytoma cell line, inhibition of pan class I histone deacetylases (HDACs) was identified as a mechanism to increase apoE secretion. Knocking down select HDAC family members alone or in combination revealed that inhibition of the class I HDAC family was responsible for enhancing apoE secretion. Knocking down LXRα and LXRβ genes revealed that the increase in astrocytic apoE in response to HDAC inhibition occurred via an LXR-independent pathway. Collectively, these data suggest that pan class I HDAC inhibition is a novel pathway for regulating astrocytic apoE secretion.

  12. Insulin Regulates Hepatic Triglyceride Secretion and Lipid Content via Signaling in the Brain.

    Science.gov (United States)

    Scherer, Thomas; Lindtner, Claudia; O'Hare, James; Hackl, Martina; Zielinski, Elizabeth; Freudenthaler, Angelika; Baumgartner-Parzer, Sabina; Tödter, Klaus; Heeren, Joerg; Krššák, Martin; Scheja, Ludger; Fürnsinn, Clemens; Buettner, Christoph

    2016-06-01

    Hepatic steatosis is common in obesity and insulin resistance and results from a net retention of lipids in the liver. A key mechanism to prevent steatosis is to increase secretion of triglycerides (TG) packaged as VLDLs. Insulin controls nutrient partitioning via signaling through its cognate receptor in peripheral target organs such as liver, muscle, and adipose tissue and via signaling in the central nervous system (CNS) to orchestrate organ cross talk. While hepatic insulin signaling is known to suppress VLDL production from the liver, it is unknown whether brain insulin signaling independently regulates hepatic VLDL secretion. Here, we show that in conscious, unrestrained male Sprague Dawley rats the infusion of insulin into the third ventricle acutely increased hepatic TG secretion. Chronic infusion of insulin into the CNS via osmotic minipumps reduced the hepatic lipid content as assessed by noninvasive (1)H-MRS and lipid profiling independent of changes in hepatic de novo lipogenesis and food intake. In mice that lack the insulin receptor in the brain, hepatic TG secretion was reduced compared with wild-type littermate controls. These studies identify brain insulin as an important permissive factor in hepatic VLDL secretion that protects against hepatic steatosis. © 2016 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

  13. Profiling of proteins secreted in the bovine oviduct reveals diverse functions of this luminal microenvironment.

    Directory of Open Access Journals (Sweden)

    Viju Vijayan Pillai

    Full Text Available The oviductal microenvironment is a site for key events that involve gamete maturation, fertilization and early embryo development. Secretions into the oviductal lumen by either the lining epithelium or by transudation of plasma constituents are known to contain elements conducive for reproductive success. Although previous studies have identified some of these factors involved in reproduction, knowledge of secreted proteins in the oviductal fluid remains rudimentary with limited definition of function even in extensively studied species like cattle. In this study, we used a shotgun proteomics approach followed by bioinformatics sequence prediction to identify secreted proteins present in the bovine oviductal fluid (ex vivo and secretions from the bovine oviductal epithelial cells (in vitro. From a total of 2087 proteins identified, 266 proteins could be classified as secreted, 109 (41% of which were common for both in vivo and in vitro conditions. Pathway analysis indicated different classes of proteins that included growth factors, metabolic regulators, immune modulators, enzymes, and extracellular matrix components. Functional analysis revealed mechanisms in the oviductal lumen linked to immune homeostasis, gamete maturation, fertilization and early embryo development. These results point to several novel components that work together with known elements mediating functional homeostasis, and highlight the diversity of machinery associated with oviductal physiology and early events in cattle fertility.

  14. Applying unconventional secretion of the endochitinase Cts1 to export heterologous proteins in Ustilago maydis.

    Science.gov (United States)

    Stock, Janpeter; Sarkari, Parveen; Kreibich, Saskia; Brefort, Thomas; Feldbrügge, Michael; Schipper, Kerstin

    2012-10-15

    The demand on the biotechnological production of proteins for pharmaceutical, medical and industrial applications is steadily growing. For the production of challenging proteins, we aim to establish a novel expression platform in the well characterized eukaryotic microorganism Ustilago maydis. In filaments of this fungus, secretion of the endochitinase Cts1 depends on mRNA transport along microtubules, which is mediated by the key RNA-binding protein Rrm4. Here, we report two important findings: (i) Cts1 secretion occurs via a novel unconventional route and (ii) this secretory mechanism can be exploited for the export of active heterologous proteins. Initially, we used β-glucuronidase (Gus) as a reporter for unconventional secretion. This bacterial enzyme is inactivated by N-glycosylation during its passage through the conventional eukaryotic secretory pathway. By contrast, in our system Gus was exported in its active form by fusion to Cts1 confirming its secretion by an unconventional route. As a proof-of-principle for economically important biopharmaceuticals we expressed an active single-chain antibody. Importantly, the novel protein export pathway circumvents N-glycosylation which is advantageous in many applications, e.g., to avoid undesired immune reactions in humans. Thus, the unconventional Cts1 secretion machinery has a high potential for the production of biotechnologically relevant proteins. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. Dispatched and Scube Mediate the Efficient Secretion of the Cholesterol-Modified Hedgehog Ligand

    Directory of Open Access Journals (Sweden)

    Hanna Tukachinsky

    2012-08-01

    Full Text Available The Hedgehog (Hh signaling pathway plays critical roles in metazoan development and in cancer. How the Hh ligand is secreted and spreads to distant cells is unclear, given its covalent modification with a hydrophobic cholesterol molecule, which makes it stick to membranes. We demonstrate that Hh ligand secretion from vertebrate cells is accomplished via two distinct and synergistic cholesterol-dependent binding events, mediated by two proteins that are essential for vertebrate Hh signaling: the membrane protein Dispatched (Disp and a member of the Scube family of secreted proteins. Cholesterol modification is sufficient for a heterologous protein to interact with Scube and to be secreted in a Scube-dependent manner. Disp and Scube recognize different structural aspects of cholesterol similarly to how Niemann-Pick disease proteins 1 and 2 interact with cholesterol, suggesting a hand-off mechanism for transferring Hh from Disp to Scube. Thus, Disp and Scube cooperate to dramatically enhance the secretion and solubility of the cholesterol-modified Hh ligand.

  16. Dispatched and scube mediate the efficient secretion of the cholesterol-modified hedgehog ligand.

    Science.gov (United States)

    Tukachinsky, Hanna; Kuzmickas, Ryan P; Jao, Cindy Y; Liu, Jing; Salic, Adrian

    2012-08-30

    The Hedgehog (Hh) signaling pathway plays critical roles in metazoan development and in cancer. How the Hh ligand is secreted and spreads to distant cells is unclear, given its covalent modification with a hydrophobic cholesterol molecule, which makes it stick to membranes. We demonstrate that Hh ligand secretion from vertebrate cells is accomplished via two distinct and synergistic cholesterol-dependent binding events, mediated by two proteins that are essential for vertebrate Hh signaling: the membrane protein Dispatched (Disp) and a member of the Scube family of secreted proteins. Cholesterol modification is sufficient for a heterologous protein to interact with Scube and to be secreted in a Scube-dependent manner. Disp and Scube recognize different structural aspects of cholesterol similarly to how Niemann-Pick disease proteins 1 and 2 interact with cholesterol, suggesting a hand-off mechanism for transferring Hh from Disp to Scube. Thus, Disp and Scube cooperate to dramatically enhance the secretion and solubility of the cholesterol-modified Hh ligand. Copyright © 2012 The Authors. Published by Elsevier Inc. All rights reserved.

  17. An optimized approach to recover secreted proteins from fibroblast conditioned-media for secretomic analysis

    Directory of Open Access Journals (Sweden)

    Bastien ePare

    2016-03-01

    Full Text Available The proteins secreted by a particular type of cell, the secretome, play important roles in the regulation of many physiological processes via paracrine/autocrine mechanisms, and they are of increasing interest to help understanding rare diseases and to identify potential biomarkers and therapeutic targets. To facilitate ongoing research involving secreted proteins, we revisited cell culture protocols and whole secreted protein enrichment protocols. A reliable method for culturing and precipitating secreted protein from patient-derived fibroblast conditioned-medium was established. The method is based on the optimization of cell confluency and incubation time conditions. The well-established carrier-based TCA-DOC protein precipitation method was consistently found to give higher protein recovery yield. According to our results, we therefore propose that protein enrichment should be performed by TCA-DOC precipitation method 48 hours at 95% of confluence in a serum-deprived culture medium. Given the importance of secreted proteins as a source to elucidate the pathogenesis of rare diseases, especially neurological disorders, this approach may help to discover novel candidate biomarkers with potential clinical significance.

  18. Intracellular and extracellular adenosine triphosphate in regulation of insulin secretion from pancreatic β cells (β).

    Science.gov (United States)

    Wang, Chunjiong; Geng, Bin; Cui, Qinghua; Guan, Youfei; Yang, Jichun

    2014-03-01

    Adenosine triphosphate (ATP) synthesis and release in mitochondria play critical roles in regulating insulin secretion in pancreatic β cells. Mitochondrial dysfunction is mainly characterized by a decrease in ATP production, which is a central event in the progression of pancreatic β cell dysfunction and diabetes. ATP has been demonstrated to regulate insulin secretion via several pathways: (i) Intracellular ATP directly closes ATP-sensitive potassium channel to open L-type calcium channel, leading to an increase in free cytosolic calcium levels and exocytosis of insulin granules; (ii) A decrease in ATP production is always associated with an increase in production of reactive oxygen species, which exerts deleterious effects on pancreatic β cell survival and insulin secretion; and (iii) ATP can be co-secreted with insulin from pancreatic β cells, and the released ATP functions as an autocrine signal to modulate insulin secretory process via P2 receptors on the cell membrane. In this review, the recent findings regarding the role and mechanism of ATP synthesis and release in regulation of insulin secretion from pancreatic β cells will be summarized and discussed. © 2013 Ruijin Hospital, Shanghai Jiaotong University School of Medicine and Wiley Publishing Asia Pty Ltd.

  19. Digestive physiology of the pig symposium: secretion of gastrointestinal hormones and eating control.

    Science.gov (United States)

    Steinert, R E; Feinle-Bisset, C; Geary, N; Beglinger, C

    2013-05-01

    Nutrient ingestion triggers numerous changes in gastrointestinal (GI) peptide hormone secretion that affect appetite and eating. Evidence for these effects comes from research in laboratory animals, healthy humans, and, increasingly, obese patients after Roux-en-Y gastric bypass (RYGB) surgery, which has marked effects on GI hormone function and is currently the most effective therapy for morbid obesity. Increases in cholecystokinin (CCK), glucagon-like peptide-1 (GLP-1), and peptide tyrosine tyrosine (PYY) and decreases in ghrelin secretion after meals are triggered by changes in the nutrient content of the intestine. One apparent physiological function of each is to initiate a reflex-like feedback control of eating. Here we briefly review this function, with an emphasis on the controls of their secretion. Each is secreted from enteroendocrine cells that are directly or indirectly affected by caloric load, macronutrient composition, and other characteristics of ingested food such as fatty acid chain length. In addition, digestive hydrolysis is a critical mechanism that controls their secretion. Although there are relatively few data in agricultural animals, the generally consistent results across widely divergent mammals suggests that most of the processes described are also likely to be relevant to GI hormone functions and eating in agricultural animals.

  20. Profiling of proteins secreted in the bovine oviduct reveals diverse functions of this luminal microenvironment.

    Science.gov (United States)

    Pillai, Viju Vijayan; Weber, Darren M; Phinney, Brett S; Selvaraj, Vimal

    2017-01-01

    The oviductal microenvironment is a site for key events that involve gamete maturation, fertilization and early embryo development. Secretions into the oviductal lumen by either the lining epithelium or by transudation of plasma constituents are known to contain elements conducive for reproductive success. Although previous studies have identified some of these factors involved in reproduction, knowledge of secreted proteins in the oviductal fluid remains rudimentary with limited definition of function even in extensively studied species like cattle. In this study, we used a shotgun proteomics approach followed by bioinformatics sequence prediction to identify secreted proteins present in the bovine oviductal fluid (ex vivo) and secretions from the bovine oviductal epithelial cells (in vitro). From a total of 2087 proteins identified, 266 proteins could be classified as secreted, 109 (41%) of which were common for both in vivo and in vitro conditions. Pathway analysis indicated different classes of proteins that included growth factors, metabolic regulators, immune modulators, enzymes, and extracellular matrix components. Functional analysis revealed mechanisms in the oviductal lumen linked to immune homeostasis, gamete maturation, fertilization and early embryo development. These results point to several novel components that work together with known elements mediating functional homeostasis, and highlight the diversity of machinery associated with oviductal physiology and early events in cattle fertility.

  1. Profiling of proteins secreted in the bovine oviduct reveals diverse functions of this luminal microenvironment

    Science.gov (United States)

    Pillai, Viju Vijayan; Weber, Darren M.; Phinney, Brett S.

    2017-01-01

    The oviductal microenvironment is a site for key events that involve gamete maturation, fertilization and early embryo development. Secretions into the oviductal lumen by either the lining epithelium or by transudation of plasma constituents are known to contain elements conducive for reproductive success. Although previous studies have identified some of these factors involved in reproduction, knowledge of secreted proteins in the oviductal fluid remains rudimentary with limited definition of function even in extensively studied species like cattle. In this study, we used a shotgun proteomics approach followed by bioinformatics sequence prediction to identify secreted proteins present in the bovine oviductal fluid (ex vivo) and secretions from the bovine oviductal epithelial cells (in vitro). From a total of 2087 proteins identified, 266 proteins could be classified as secreted, 109 (41%) of which were common for both in vivo and in vitro conditions. Pathway analysis indicated different classes of proteins that included growth factors, metabolic regulators, immune modulators, enzymes, and extracellular matrix components. Functional analysis revealed mechanisms in the oviductal lumen linked to immune homeostasis, gamete maturation, fertilization and early embryo development. These results point to several novel components that work together with known elements mediating functional homeostasis, and highlight the diversity of machinery associated with oviductal physiology and early events in cattle fertility. PMID:29155854

  2. Interleukin-17A induces bicarbonate secretion in normal human bronchial epithelial cells

    Science.gov (United States)

    Kreindler, James L.; Bertrand, Carol A.; Lee, Robert J.; Karasic, Thomas; Aujla, Shean; Pilewski, Joseph M.; Frizzell, Raymond A.; Kolls, Jay K.

    2009-01-01

    The innate immune functions of human airways include mucociliary clearance and antimicrobial peptide activity. Both functions may be affected by changes in epithelial ion transport. Interleukin-17A (IL-17A), which has a receptor at the basolateral membrane of airway epithelia, is a T cell cytokine that has been shown to increase mucus secretion and antimicrobial peptide production by human bronchial epithelial (HBE) cells. Furthermore, IL-17A levels are increased in sputum from patients during pulmonary exacerbations of cystic fibrosis. Therefore, we investigated the effects of IL-17A on basal, amiloride-sensitive, and forskolin-stimulated ion transport in mature, well-differentiated HBE cells. Exposure of HBE monolayers to IL-17A for 48 h induced a novel forskolin-stimulated bicarbonate secretion in addition to forskolin-stimulated chloride secretion and resulted in alkalinization of liquid on the mucosal surface of polarized cells. IL-17A-induced bicarbonate secretion was cystic fibrosis transmembrane conductance regulator (CFTR)-dependent, mucosal chloride-dependent, partially Na+-dependent, and sensitive to serosal, but not mucosal, stilbene inhibition. These data suggest that IL-17A modulates epithelial bicarbonate secretion and implicate a mechanism by which airway surface liquid pH changes may be abnormal in cystic fibrosis. PMID:19074559

  3. GLP-1 stimulates insulin secretion by PKC-dependent TRPM4 and TRPM5 activation.

    Science.gov (United States)

    Shigeto, Makoto; Ramracheya, Reshma; Tarasov, Andrei I; Cha, Chae Young; Chibalina, Margarita V; Hastoy, Benoit; Philippaert, Koenraad; Reinbothe, Thomas; Rorsman, Nils; Salehi, Albert; Sones, William R; Vergari, Elisa; Weston, Cathryn; Gorelik, Julia; Katsura, Masashi; Nikolaev, Viacheslav O; Vennekens, Rudi; Zaccolo, Manuela; Galione, Antony; Johnson, Paul R V; Kaku, Kohei; Ladds, Graham; Rorsman, Patrik

    2015-12-01

    Strategies aimed at mimicking or enhancing the action of the incretin hormone glucagon-like peptide 1 (GLP-1) therapeutically improve glucose-stimulated insulin secretion (GSIS); however, it is not clear whether GLP-1 directly drives insulin secretion in pancreatic islets. Here, we examined the mechanisms by which GLP-1 stimulates insulin secretion in mouse and human islets. We found that GLP-1 enhances GSIS at a half-maximal effective concentration of 0.4 pM. Moreover, we determined that GLP-1 activates PLC, which increases submembrane diacylglycerol and thereby activates PKC, resulting in membrane depolarization and increased action potential firing and subsequent stimulation of insulin secretion. The depolarizing effect of GLP-1 on electrical activity was mimicked by the PKC activator PMA, occurred without activation of PKA, and persisted in the presence of PKA inhibitors, the KATP channel blocker tolbutamide, and the L-type Ca(2+) channel blocker isradipine; however, depolarization was abolished by lowering extracellular Na(+). The PKC-dependent effect of GLP-1 on membrane potential and electrical activity was mediated by activation of Na(+)-permeable TRPM4 and TRPM5 channels by mobilization of intracellular Ca(2+) from thapsigargin-sensitive Ca(2+) stores. Concordantly, GLP-1 effects were negligible in Trpm4 or Trpm5 KO islets. These data provide important insight into the therapeutic action of GLP-1 and suggest that circulating levels of this hormone directly stimulate insulin secretion by β cells.

  4. A substrate-fusion protein is trapped inside the Type III Secretion System channel in Shigella flexneri.

    Directory of Open Access Journals (Sweden)

    Kim Dohlich

    2014-01-01

    Full Text Available The Type III Secretion System (T3SS is a macromolecular complex used by Gram-negative bacteria to secrete effector proteins from the cytoplasm across the bacterial envelope in a single step. For many pathogens, the T3SS is an essential virulence factor that enables the bacteria to interact with and manipulate their respective host. A characteristic structural feature of the T3SS is the needle complex (NC. The NC resembles a syringe with a basal body spanning both bacterial membranes and a long needle-like structure that protrudes from the bacterium. Based on the paradigm of a syringe-like mechanism, it is generally assumed that effectors and translocators are unfolded and secreted from the bacterial cytoplasm through the basal body and needle channel. Despite extensive research on T3SS, this hypothesis lacks experimental evidence and the mechanism of secretion is not fully understood. In order to elucidate details of the T3SS secretion mechanism, we generated fusion proteins consisting of a T3SS substrate and a bulky protein containing a knotted motif. Because the knot cannot be unfolded, these fusions are accepted as T3SS substrates but remain inside the NC channel and obstruct the T3SS. To our knowledge, this is the first time substrate fusions have been visualized together with isolated NCs and we demonstrate that substrate proteins are secreted directly through the channel with their N-terminus first. The channel physically encloses the fusion protein and shields it from a protease and chemical modifications. Our results corroborate an elementary understanding of how the T3SS works and provide a powerful tool for in situ-structural investigations in the future. This approach might also be applicable to other protein secretion systems that require unfolding of their substrates prior to secretion.

  5. Neuroimmune mechanisms in functional bowel disorders

    NARCIS (Netherlands)

    Wouters, M. M.; Boeckxstaens, G. E.

    2011-01-01

    The enteric nervous system regulates diverse functions including gastrointestinal motility and nociception. The sensory neurons detect mechanical and chemical stimuli while motor neurons control peristalsis and secretion. In addition to this extensive neuronal network, the gut also houses a highly

  6. Secretion of SerpinB2 from endothelial cells activated with inflammatory stimuli

    Energy Technology Data Exchange (ETDEWEB)

    Boncela, Joanna; Przygodzka, Patrycja [Institute of Medical Biology, Polish Academy of Sciences, Lodz (Poland); Wyroba, Elzbieta [Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw (Poland); Papiewska-Pajak, Izabela [Department of Molecular and Medical Biophysics, Medical University of Lodz (Poland); Cierniewski, Czeslaw S., E-mail: czeslaw.cierniewski@umed.lodz.pl [Institute of Medical Biology, Polish Academy of Sciences, Lodz (Poland); Department of Molecular and Medical Biophysics, Medical University of Lodz (Poland)

    2013-05-01

    Due to the lack of an N-terminal signal peptide, SerpinB2 (plasminogen activator inhibitor type 2) accumulates in cells and only a small percentage of it is secreted. The extracellular concentration of SerpinB2 significantly increases during inflammation. In the present study we investigated the mechanism with which SerpinB2 can be secreted from endothelial cells activated with LPS. We evaluated the intracellular distribution of SerpinB2 by double immunogold labeling followed by a high resolution electron microscopy analysis. We found that SerpinB2 gathers in the vesicular structures and in the endothelial cell periphery. These vesicles stained positive for the trans-Golgi network marker TGN46, which is consistent with their formation by the endoplasmatic reticulum (ER) and Golgi-dependent pathways. SerpinB2 was delivered to the plasma membrane, apparently together with TGN46 in the same vesicles, which after fusion with the membranes released cargo. Secretion of SerpinB2 was partially inhibited by brefeldin A. The secreted SerpinB2 was predominantly in its nonglycosylated 43 kDa form as evaluated by Western immunoblotting. Our data suggest that increased expression of SerpinB2 by an inflammatory stimulus is sufficient to generate structures that resemble secretory vesicles. These vesicles may represent the mechanism by which high local concentrations of SerpinB2 are released at inflammation sites from endothelial cells. - Highlights: ► LPS stimulates generation of secretory vesicles containing SerpinB2. ► SerpinB2 concentrates in TGN46 positive vesicles close to the plasma membrane. ► Brefeldin A inhibits secretion of SerpinB2. ► The secreted SerpinB2 was predominantly in its nonglycosylated 43 kDa.

  7. Estrogen inhibits chloride secretion caused by cholera and Escherichia coli enterotoxins in female rat distal colon.

    LENUS (Irish Health Repository)

    Alzamora, Rodrigo

    2012-02-01

    Excessive Cl(-) secretion is the driving force for secretory diarrhea. 17beta-Estradiol has been shown to inhibit Cl(-) secretion in rat distal colon through a nongenomic pathway. We examined whether 17beta-estradiol inhibits Cl(-) secretion in an animal model of secretory diarrhea and the downstream effectors involved. The effect of 17beta-estradiol on cholera toxin and heat-stable enterotoxin induced Cl(-) secretion in rat colonic mucosal sheets was studied by current-voltage clamping. Selective permeabilization of apical or basolateral membranes with amphotericin B or nystatin was used to isolate basolateral K(+) channel and apical Cl(-) channel activity, respectively. 17beta-Estradiol dose-dependently inhibited secretory responses to both toxins with IC(50) values of approximately 1nM. This effect was female-gender specific, with no inhibition observed in male tissues. 17beta-Estradiol responses were insensitive to the pure anti-estrogen ICI 182,720. 17beta-Estradiol exerted its effects downstream of enterotoxin-induced production of second messengers (cAMP and cGMP) but was dependent on PKCdelta activation. In nystatin-permeabilized tissues, apical Cl(-) currents were unaffected by 17beta-estradiol treatment while basolateral K(+) current was profoundly inhibited by the hormone. This current was sensitive to the specific KCNQ1 channel inhibitors chromanol 293B and HMR-1556. In conclusion, 17beta-estradiol inhibits enterotoxin-induced Cl(-) secretion via a PKCdelta-dependent mechanism involving inhibition of basolateral KCNQ1 channels. These data elucidate mechanisms of 17beta-estradiol inhibition of Cl(-) secretion induced by enterotoxins in intestinal epithelia, which may be relevant for the treatment of diarrheal diseases.

  8. Estrogen inhibits chloride secretion caused by cholera and Escherichia coli enterotoxins in female rat distal colon.

    LENUS (Irish Health Repository)

    Alzamora, Rodrigo

    2011-05-08

    Excessive Cl(-) secretion is the driving force for secretory diarrhea. 17β-Estradiol has been shown to inhibit Cl(-) secretion in rat distal colon through a nongenomic pathway. We examined whether 17β-estradiol inhibits Cl(-) secretion in an animal model of secretory diarrhea and the downstream effectors involved. The effect of 17β-estradiol on cholera toxin and heat-stable enterotoxin induced Cl(-) secretion in rat colonic mucosal sheets was studied by current-voltage clamping. Selective permeabilization of apical or basolateral membranes with amphotericin B or nystatin was used to isolate basolateral K(+) channel and apical Cl(-) channel activity, respectively. 17β-Estradiol dose-dependently inhibited secretory responses to both toxins with IC(50) values of approximately 1nM. This effect was female-gender specific, with no inhibition observed in male tissues. 17β-Estradiol responses were insensitive to the pure anti-estrogen ICI 182,720. 17β-Estradiol exerted its effects downstream of enterotoxin-induced production of second messengers (cAMP and cGMP) but was dependent on PKCδ activation. In nystatin-permeabilized tissues, apical Cl(-) currents were unaffected by 17β-estradiol treatment while basolateral K(+) current was profoundly inhibited by the hormone. This current was sensitive to the specific KCNQ1 channel inhibitors chromanol 293B and HMR-1556. In conclusion, 17β-estradiol inhibits enterotoxin-induced Cl(-) secretion via a PKCδ-dependent mechanism involving inhibition of basolateral KCNQ1 channels. These data elucidate mechanisms of 17β-estradiol inhibition of Cl(-) secretion induced by enterotoxins in intestinal epithelia, which may be relevant for the treatment of diarrheal diseases.

  9. Trade Secrets in Life Science and Pharmaceutical Companies

    Science.gov (United States)

    Nealey, Tara; Daignault, Ronald M.; Cai, Yu

    2015-01-01

    Trade secret protection arises under state common law and state statutes. In general, a trade secret is information that is not generally known to the public and is maintained as a secret, and it provides a competitive advantage or economic benefit to the trade secret holder. Trade secrets can be worth tens or hundreds of millions of dollars, and damage awards in trade secret litigation have been high; often, there is a lot at stake. Obtaining a trade secret through “improper means” is misappropriation. If the alleged trade secret, however, was developed independently, known publicly, or not maintained as a secret, then those defenses may successfully overcome a claim for trade secret misappropriation. With today’s interconnectedness in the biotechnology and pharmaceutical fields, more collaborations, joint ventures, and outsourcing arrangements among firms, and increased mobility of employees’ careers, life science companies need to not only understand how to protect their trade secrets, but also know how to defend against a claim for trade secret theft. PMID:25414378

  10. Hoopoes color their eggs with antimicrobial uropygial secretions

    Science.gov (United States)

    Soler, Juan J.; Martín-Vivaldi, M.; Peralta-Sánchez, J. M.; Arco, L.; Juárez-García-Pelayo, N.

    2014-09-01

    Uropygial gland secretions are used as cosmetics by some species of birds to color and enhance properties of feathers and teguments, which may signal individual quality. Uropygial secretions also reach eggshells during incubation and, therefore, may influence the coloration of birds' eggs, a trait that has attracted the attention of evolutionary biologists for more than one century. The color of hoopoe eggs typically changes along incubation, from bluish-gray to greenish-brown. Here, we test experimentally the hypothesis that dark uropygial secretion of females is responsible for such drastic color change. Moreover, since uropygial secretion of hoopoes has antimicrobial properties, we also explore the association between color and antimicrobial activity of the uropygial secretion of females. We found that eggs stayed bluish-gray in nests where female access to the uropygial secretion was experimentally blocked. Furthermore, experimental eggs that were maintained in incubators and manually smeared with uropygial secretion experienced similar color changes that naturally incubated eggs did, while control eggs that were not in contact with the secretions did not experience such color changes. All these results strongly support the hypothesis that female hoopoes use their uropygial gland secretion to color the eggs. Moreover, saturation of the uropygial secretion was associated with antimicrobial activity against Bacillus licheniformis. Given the known antimicrobial potential of uropygial secretions of birds, this finding opens the possibility that in scenarios of sexual selection, hoopoes in particular and birds in general signal antimicrobial properties of their uropygial secretion by mean of changes in egg coloration along incubation.

  11. Trade secrets in life science and pharmaceutical companies.

    Science.gov (United States)

    Nealey, Tara; Daignault, Ronald M; Cai, Yu

    2014-11-20

    Trade secret protection arises under state common law and state statutes. In general, a trade secret is information that is not generally known to the public and is maintained as a secret, and it provides a competitive advantage or economic benefit to the trade secret holder. Trade secrets can be worth tens or hundreds of millions of dollars, and damage awards in trade secret litigation have been high; often, there is a lot at stake. Obtaining a trade secret through "improper means" is misappropriation. If the alleged trade secret, however, was developed independently, known publicly, or not maintained as a secret, then those defenses may successfully overcome a claim for trade secret misappropriation. With today's interconnectedness in the biotechnology and pharmaceutical fields, more collaborations, joint ventures, and outsourcing arrangements among firms, and increased mobility of employees' careers, life science companies need to not only understand how to protect their trade secrets, but also know how to defend against a claim for trade secret theft. Copyright © 2015 Cold Spring Harbor Laboratory Press; all rights reserved.

  12. Secretion of Flavins by Three Species of Methanotrophic Bacteria▿ †

    OpenAIRE

    Balasubramanian, Ramakrishnan; Levinson, Benjamin T.; Rosenzweig, Amy C.

    2010-01-01

    We detected flavins in the growth medium of the methanotrophic bacterium Methylocystis species strain M. Flavin secretion correlates with growth stage and increases under iron starvation conditions. Two other methanotrophs, Methylosinus trichosporium OB3b and Methylococcus capsulatus (Bath), secrete flavins, suggesting that flavin secretion may be common to many methanotrophic bacteria.

  13. 10 CFR 1016.34 - Accountability for Secret Restricted Data.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Accountability for Secret Restricted Data. 1016.34 Section... Information § 1016.34 Accountability for Secret Restricted Data. Each permittee possessing documents containing Secret Restricted Data shall establish a document accountability procedure and shall maintain...

  14. Expression and Quorum Sensing Regulation of Type III Secretion System Genes of Vibrio harveyi during Infection of Gnotobiotic Brine Shrimp.

    Directory of Open Access Journals (Sweden)

    H A Darshanee Ruwandeepika

    Full Text Available Type III secretion systems enable pathogens to inject their virulence factors directly into the cytoplasm of the host cells. The type III secretion system of Vibrio harveyi, a major pathogen of aquatic organisms and a model species in quorum sensing studies, is repressed by the quorum sensing master regulator LuxR. In this study, we found that during infection of gnotobiotic brine shrimp larvae, the expression levels of three type III secretion operons in V. harveyi increased within the first 12h after challenge and decreased again thereafter. The in vivo expression levels were highest in a mutant with a quorum sensing system that is locked in low cell density configuration (minimal LuxR levels and lowest in a mutant with a quorum sensing system that is locked in the high cell density configuration (maximal LuxR levels, which is consistent with repression of type III secretion by LuxR. Remarkably, in vivo expression levels of the type III secretion system genes were much (> 1000 fold higher than the in vitro expression levels, indicating that (currently unknown host factors significantly induce the type III secretion system. Given the fact that type III secretion is energy-consuming, repression by the quorum sensing master regulators might be a mechanism to save energy under conditions where it does not provide an advantage to the cells.

  15. Effect of acute ethanol on beta-endorphin secretion from rat fetal hypothalamic neurons in primary cultures

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, D.K.; Minami, S. (Washington State Univ., Pullman (USA))

    1990-01-01

    To characterize the effect of ethanol on the hypothalamic {beta}-endorphin-containing neurons, rat fetal hypothalamic neurons were maintained in primary culture, and the secretion of {beta}-endorphin ({beta}-EP) was determined after ethanol challenges. Constant exposure to ethanol at doses of 6-50 mM produced a dose-dependent increase in basal secretion of {beta}-EP from these cultured cells. These doses of ethanol did not produce any significant effect on cell viability, DNA or protein content. The stimulated secretion of {beta}-EP following constant ethanol exposure is short-lasting. However, intermittent ethanol exposures maintained the ethanol stimulatory action on {beta}-EP secretion for a longer time. The magnitude of the {beta}-EP response to 50 mM ethanol is similar to that of the {beta}-EP response to 56 mM of potassium. Ethanol-stimulated {beta}-EP secretion required extracellular calcium and was blocked by a calcium channel blocker; a sodium channel blocker did not affect ethanol-stimulated secretion. These results suggest that the neuron culture system is a useful model for studying the cellular mechanisms involved in the ethanol-regulated hypothalamic opioid secretion.

  16. Bile acids are important direct and indirect regulators of the secretion of appetite- and metabolism-regulating hormones from the gut and pancreas

    DEFF Research Database (Denmark)

    Kuhre, Rune Ehrenreich; Albrechtsen, Nicolai Jacob Wewer; Larsen, Olav

    2018-01-01

    OBJECTIVE: Bile acids (BAs) facilitate fat absorption and may play a role in glucose and metabolism regulation, stimulating the secretion of gut hormones. The relative importance and mechanisms involved in BA-stimulated secretion of appetite and metabolism regulating hormones from the gut...... and pancreas is not well described and was the purpose of this study. METHODS: The effects of bile acids on the secretion of gut and pancreatic hormones was studied in rats and compared to the most well described nutritional secretagogue: glucose. The molecular mechanisms that underlie the secretion...... was studied by isolated perfused rat and mouse small intestine and pancreas preparations and supported by immunohistochemistry, expression analysis, and pharmacological studies. RESULTS: Bile acids robustly stimulate secretion of not only the incretin hormones, glucose-dependent insulinotropic peptide (GIP...

  17. Radioimmunoassay of glicagon secretion in diabetes mellitus

    International Nuclear Information System (INIS)

    Milanova, St.; Koparanova, O.; Milkov, V.; Visheva, N.; Kurtev, I.; Maleeva, A.

    1988-01-01

    Radioimunoassay of glucagon, lh, fsh, aldosterone, cortisol, acth, sth and lth was performed using preparations from the firms SORIN, AMERSHAM and HOECHST. The basal glucagon secretion was estimated in 403 diabetic patients and 84 normal subjects. It was transitorily suppressed by glucose. The alpha-cellular reactivity in diabetic patients was stimulated by insulin-induced hypoglycemia and with arginine and vasopressin. The tested group of diabetic patients had absolute hyperglucagonemia, despite the hyperglycemia, which is an evidence of abnormal alpha-cellular function. The insulin-dependent nature of hyperglucagonemia in diabetes mellitus and the hyperreactivity of glucagon secretion after protein stimulation was demonstrated. The correlation of these results leads to essential diagnostic inferences

  18. Tachykinin receptors mediating airway marcomolecular secretion

    Energy Technology Data Exchange (ETDEWEB)

    Gentry, S.E. (Univ. of Pittsburgh School of Medicine, PA (USA))

    1991-01-01

    Three tachykinin receptor types, termed NK1, NK2, and NK3, can be distinguished by the relative potency of various peptides in eliciting tissue responses. Airway macromolecular secretion is stimulated by the tachykinin substance P (SP). The purposes of this study were to determine the tachykinin receptor subtype responsible for this stimulation, and to examine the possible involvement of other neurotransmitters in mediating this effect. Ferret tracheal explants maintained in organ culture were labeled with {sup 3}H-glucosamine, a precursor of high molecular weight glycoconjugates (HMWG) which are released by airway secretory cells. Secretion of labeled HMWG then was determined in the absence and presence of the tachykinins SP, neurokinin A (NKA), neurokinin B (NKB), physalaemin (PHY), and eledoisin (ELE). To evaluate the possible contribution of other mediators, tachykinin stimulation was examined in the presence of several receptor blockers.

  19. Secrets of over-indebted people

    Directory of Open Access Journals (Sweden)

    Valérie BILLAUDEAU

    2013-12-01

    Full Text Available Today, the economic and financial crisis is brought to light and it is now clear that many people are directly impacted by this phenomenon. However, a lot of situations are obviously hidden and in particular those concerning over-indebted people. These people often find that it is difficult to express the hardship they are going through and keep silent because is more comfortable for them. The media also does not tackle this burning issue because the complexity of some situations complicates the message. Therefore, a giant gap has appeared leaving over-indebted people entrapped in their secret. Starting from this hypothesis, this article will examine the results of a research conducted on the over-indebted people (survey on written press, analysis of TV broadcasts, analysis of records related to person in debts and responses of people in debts and the secrets that this phenomenon involves.

  20. Analysis of Secreted Proteins Using SILAC

    DEFF Research Database (Denmark)

    Henningsen, Jeanette; Blagoev, Blagoy; Kratchmarova, Irina

    2014-01-01

    Secreted proteins serve a crucial role in the communication between cells, tissues, and organs. Proteins released to the extracellular environment exert their function either locally or at distant points of the organism. Proteins are secreted in a highly dynamic fashion by cells and tissues...... in the body responding to the stimuli and requirements presented by the extracellular milieu. Characterization of secretomes derived from various cell types has been performed using different quantitative mass spectrometry-based proteomics strategies, several of them taking advantage of labeling with stable...... isotopes. Here, we describe the use of Stable Isotope Labeling by Amino acids in Cell culture (SILAC) for the quantitative analysis of the skeletal muscle secretome during myogenesis....

  1. Potassium secretion in mammalian distal colon

    DEFF Research Database (Denmark)

    Sørensen, Mads Vaarby

    2009-01-01

    . This research project is the summary of 3 original papers addressing the functional role of different regulating factors on ion transport in mouse distal colon. The first paper addresses the effect of luminal nucleotides on electrogenic Na+ absorption. The distal colon, like the distal nephron is an aldosterone......2 subunits in mice treated on an aldosterone increasing diet (high K+). Immunolabelling showed BK channel localisation in the luminal membrane which also was up-regulated in animals treated on a high K+ diet. Taken together these results firmly prove that aldosterone-stimulated K+ secretion......-/- mouse, we could functionally isolate the cAMP-activated K+ conductance as the BK channel. In addition we found the cAMP-activated K+ conductance to be further up-regulated by aldosterone. Taken together, these results show cAMP-activated K+ secretion occurs via a regulated specific splice variant...

  2. Growth hormone secretion in protein energy malnutrition.

    Science.gov (United States)

    Günöz, H; Neyzł, O; Sencer, E; Molvalilar, S; Argun, A

    1981-07-01

    Plasma hGH levels were assessed in 15 infants with protein energy malnutrition following insulin induced hypoglycemia, arginine and L-Dopa provocation tests and intravenous glucose tolerance test. Fasting hGH levels were high in 85.7% of the cases. An adequate hGH response to stimulation was obtained in only 42.8% of the cases with insulin induced hypoglycemia; in 52.5% with arginine; in 30.8% with L-Dopa. Response to at least one type of provocation was obtained in all 5 cases to which all three tests were applied. Exaggerated or delayed response to provocative stimuli was also encountered in a number of the cases. Intravenous glucose tolerance test did not lead to suppression in hGH secretion or to increase in insulin secretion in these subjects. The results indicate that marasmic protein energy malnutrition may lead to defects in the hGH secretory function of the hypothalamopituitary axis.

  3. George's secret key to the universe

    CERN Document Server

    Hawking, Lucy; Galfard, Christophe; Parsons, Gary

    2007-01-01

    In their bestselling book for young readers, noted physicist Stephen Hawking and his daughter, Lucy, provide a grand and funny adventure that explains fascinating information about our universe, including Dr. Hawking's latest ideas about black holes. It's the story of George, who's taken through the vastness of space by a scientist, his daughter, and their super-computer named Cosmos. George's Secret Key to the Universe was a New York Times bestseller and a selection of Al's Book Club on the Today show.

  4. Mort Rainey's Split Personality in Secret Window

    OpenAIRE

    Sandjaya, Cynthya; Limanta, Liem Satya

    2013-01-01

    Psychological issue is the main issue discussed in David Koepp's Secret Window through its main character, Mort Rainey. Rainey's psychological struggle will be the main theme in this research. This thesis examines Rainey's split personality. Furthermore, in this study, we want to analyze the process of how Mort Rainey's personality splits into two different personalities. To meet the answer of this study, we will use the theory of Dissociative Identity Disorder with a support from Sigmund Fre...

  5. Eating people is wrong: Famine's darkest secret?

    OpenAIRE

    Ó Gráda, Cormac

    2013-01-01

    Cannibalism is one of our darkest secrets and taboos. It is the ultimate measure of the resilience or otherwise of civilizational processes to extreme conditions. How common was cannibalism in times of famine in the past? Both the nature of the evidence for famine cannibalism and the silences about it challenge the empirical historian to the limit. After a review of the global historiography, this paper attempts to assess the evidence for cannibalism during Ireland’s many famines, culminating...

  6. Paliperidone Induced Hypoglycemia by Increasing Insulin Secretion

    Directory of Open Access Journals (Sweden)

    Tsubasa Omi

    2016-01-01

    Full Text Available We report the case of a 41-year-old woman with schizophrenia who developed persistent hypoglycemia following paliperidone administration. After discontinuing paliperidone, the hypoglycemia resolved, but symptoms of diabetes emerged. Therefore, it appears that the hypoglycemia induced by paliperidone may mask symptoms of diabetes. Paliperidone may induce hypoglycemia by increasing insulin secretion. This report could help elucidate the relationship between atypical antipsychotics and glucose metabolism.

  7. Paliperidone Induced Hypoglycemia by Increasing Insulin Secretion

    OpenAIRE

    Omi, Tsubasa; Riku, Keisen; Fukumoto, Motoyuki; Kanai, Koji; Omura, Yumi; Takada, Hiromune; Matunaga, Hidenori

    2016-01-01

    We report the case of a 41-year-old woman with schizophrenia who developed persistent hypoglycemia following paliperidone administration. After discontinuing paliperidone, the hypoglycemia resolved, but symptoms of diabetes emerged. Therefore, it appears that the hypoglycemia induced by paliperidone may mask symptoms of diabetes. Paliperidone may induce hypoglycemia by increasing insulin secretion. This report could help elucidate the relationship between atypical antipsychotics and glucose m...

  8. Inappropriate Vasopressin Secretion (SIADH) in Burned Patients

    Science.gov (United States)

    1983-03-01

    reportedly elevated in burned patients (12). Because further dilution of plasma, with a fall in urine concentra- of increased gluconeogenesis , burned patients... dogs , apparently through alterations seen in burned patients, tachycardia does not explain the in AVP secretion (24). Hypothyroidism is associated with...806, 27. Spielman, W.S., Davis. J.O., Gotshall, R.W.: Hypersecretion of 1967. renin in dogs with a chronic aorto-caval fistula and high-output 5

  9. The effect of alanine on glucagon secretion

    Science.gov (United States)

    Müller, Walter A.; Faloona, Gerald R.; Unger, Roger H.

    1971-01-01

    If glucagon plays a hormonal role in the regulation of gluconeogenesis from endogenous amino acids, its secretion might be stimulated by an increase in the concentration of alanine, which has recently been identified as a principal gluconeogenic precursor. To determine if this is the case, 0.75 mmole of alanine per kilo was infused into conscious dogs immediately after a priming injection of 0.25 mmole per kg for 15 min. A uniform rise in the plasma level of pancreatic glucagon, as determined by a relatively specific radioimmunoassay for pancreatic glucagon, was observed. The rise, which averaged 90 pg per ml, was highly significant at 7½ and 15 min after the start of the infusion. Insulin rose an average of only 8 μU per ml, while glucose rose an average of 10 mg per 100 ml. A lower dose of alanine, 1 mmole per kg, infused over a 1 hr period without an initial priming injection, also elicited a significant rise in glucagon measured in the pancreaticoduodenal venous plasma; glucagon rose from 350 pg per ml to 1066 pg per ml at the end of the infusion. The insulin response was modest and inconsistent, and glucose, again, rose 10 mg per 100 ml. To determine if the availability of exogenous glucose would abolish the alanine-induced rise in glucagon secretion, dogs were made hyperglycemic by a constant intravenous glucose infusion and were then given the high-dose alanine infusion. Under these circumstances, glucagon did not rise above the mean fasting concentration of 75 pg per ml, whereas mean insulin rose dramatically by more than 100 μU per ml. It was concluded that, in the fasting state, alanine does stimulate the secretion of glucagon, while having very little stimulatory effect on insulin secretion. Glucagon could, therefore, be a humoral mediator of gluconeogenesis from endogenous alanine, responding to hyperalaninemia in the fasting state, but not when exogenous glucose is available. PMID:5116210

  10. Exosomes: secreted vesicles and intercellular communications

    OpenAIRE

    Théry, Clotilde

    2011-01-01

    Exosomes are small membrane vesicles of endocytic origin secreted by most cell types, and are thought to play important roles in intercellular communications. Although exosomes were originally described in 1983, interest in these vesicles has really increased dramatically in the last 3 years, after the finding that they contain mRNA and microRNA. This discovery sparked renewed interest for the general field of membrane vesicles involved in intercellular communications, and research on these s...

  11. Network layer security and secret key authentication

    OpenAIRE

    Llovet Ureña, Marcel

    2015-01-01

    The goal of this project is to update Von Mann Young Rhee’s book, ‘Internet Security: Cryptographic Principles, Algorithms and Protocols’ which is about network layer security and secret key authentication. It is an extremely important aspect in modern life to have security in the network to protect our information and prevent eavesdroppers or maleficent programs, for example. This is the reason why this project aims to update these kinds of algorithms and hash functions. This project uses me...

  12. Secrets of mlearning failures: confronting reality

    OpenAIRE

    Cochrane, Thomas

    2012-01-01

    Having implemented and evaluated over 35 mlearning projects in a variety of contexts in higher education over the past 6 years the researcher is ready to share the untold secret: not all mlearning projects succeed! This article critiques three of the researcher’s mlearning projects that can be classed as ‘‘failures’’ and compares them to successful projects to draw out critical implications for mlearning project design and implementation to avoid common pitfalls leading to potential project f...

  13. Stimulation of Cl(-) secretion by chlorzoxazone.

    Science.gov (United States)

    Singh, A K; Devor, D C; Gerlach, A C; Gondor, M; Pilewski, J M; Bridges, R J

    2000-02-01

    We previously demonstrated that 1-ethyl-2-benzimidazolone (1-EBIO) directly activates basolateral membrane calcium-activated K(+) channels (K(Ca)), thereby stimulating Cl(-) secretion across several epithelia. In our pursuit to identify potent modulators of Cl(-) secretion that may be useful to overcome the Cl(-) secretory defect in cystic fibrosis (CF), we have identified chlorzoxazone [5-chloro-2(3H)-benzoxazolone], a clinically used centrally acting muscle relaxant, as a stimulator of Cl(-) secretion in several epithelial cell types, including T84, Calu-3, and human bronchial epithelium. The Cl(-) secretory response induced by chlorzoxazone was blocked by charybdotoxin (CTX), a known blocker of K(Ca). In nystatin-permeabilized monolayers, chlorzoxazone stimulated a basolateral membrane I(K), which was inhibited by CTX and also stimulated an apical I(Cl) that was inhibited by glibenclamide, indicating that the G(Cl) responsible for this I(Cl) may be cystic fibrosis transmembrane conductance regulator (CFTR). In membrane vesicles prepared from T84 cells, chlorzoxazone stimulated (86)Rb(+) uptake in a CTX-sensitive manner. In excised, inside-out patches, chlorzoxazone activated an inwardly-rectifying K(+) channel, which was inhibited by CTX. 6-Hydroxychlorzoxazone, the major metabolite of chlorzoxazone, did not activate K(Ca), whereas zoxazolamine (2-amino-5-chlorzoxazole) showed a similar response profile as chlorzoxazone. In normal human nasal epithelium, chlorzoxazone elicited hyperpolarization of the potential difference that was similar in magnitude to isoproterenol. However, in the nasal epithelium of CF patients with the DeltaF508 mutation of CFTR, there was no detectable Cl(-) secretory response to chlorzoxazone. These studies demonstrate that chlorzoxazone stimulates transepithelial Cl(-) secretion in normal airway epithelium in vitro and in vivo, and suggest that stimulation requires functional CFTR in the epithelia.

  14. Catechin secretion and phytotoxicity: Fact not fiction.

    Science.gov (United States)

    Bais, Harsh P; Kaushik, Shail

    2010-09-01

    Research indicates that the invasiveness of Centaurea stoebe is attributed to the stronger allelopathic effects on the native North American species than on the related European species, which is one of the unquestionable aspects of the "novel weapons hypothesis (NWH)." Studies originating from controlled to field conditions have shown that C. stoebe utilizes its biochemical potential to exert its invasiveness. The roots of C. stoebe secrete a potent phytotoxin, catechin, which has a detrimental effect on the surrounding plant species. Although, studies on catechin secretion and phytotoxicity represent one of the most well studied systems describing negative plant-plant interactions, it has also sparked controversies lately due to its phytotoxicity dosages and secretion effluxes. Previous reports negate the phytotoxic and pro-oxidant nature of catechin.1-3 In our recent study we have shown that catechin is highly phytotoxic against Arabidopsis thaliana and Festuca idahoensis. We also show that (±) catechin applied to roots of A. thaliana induces reactive oxygen species (ROS) confirming the pro-oxidant nature of catechin. In addition, activation of signature cell death genes such as acd2 and cad1 post catechin treatment in A. thaliana ascertains the phytotoxic nature of catechin.

  15. A trade secret model for genomic biobanking.

    Science.gov (United States)

    Conley, John M; Mitchell, Robert; Cadigan, R Jean; Davis, Arlene M; Dobson, Allison W; Gladden, Ryan Q

    2012-01-01

    Genomic biobanks present ethical challenges that are qualitatively unique and quantitatively unprecedented. Many critics have questioned whether the current system of informed consent can be meaningfully applied to genomic biobanking. Proposals for reform have come from many directions, but have tended to involve incremental change in current informed consent practice. This paper reports on our efforts to seek new ideas and approaches from those whom informed consent is designed to protect: research subjects. Our model emerged from semi-structured interviews with healthy volunteers who had been recruited to join either of two biobanks (some joined, some did not), and whom we encouraged to explain their concerns and how they understood the relationship between specimen contributors and biobanks. These subjects spoke about their DNA and the information it contains in ways that were strikingly evocative of the legal concept of the trade secret. They then described the terms and conditions under which they might let others study their DNA, and there was a compelling analogy to the commonplace practice of trade secret licensing. We propose a novel biobanking model based on this trade secret concept, and argue that it would be a practical, legal, and ethical improvement on the status quo. © 2012 American Society of Law, Medicine & Ethics, Inc.

  16. Extracellular vesicles secreted by Schistosoma mansoni contain protein vaccine candidates.

    Science.gov (United States)

    Sotillo, Javier; Pearson, Mark; Potriquet, Jeremy; Becker, Luke; Pickering, Darren; Mulvenna, Jason; Loukas, Alex

    2016-01-01

    Herein we show for the first time that Schistosoma mansoni adult worms secrete exosome-like extracellular vesicles ranging from 50 to 130nm in size. Extracellular vesicles were collected from the excretory/secretory products of cultured adult flukes and purified by Optiprep density gradient, resulting in highly pure extracellular vesicle preparations as confirmed by transmission electron microscopy and Nanosight tracking analysis. Extracellular vesicle proteomic analysis showed numerous known vaccine candidates, potential virulence factors and molecules implicated in feeding. These findings provide new avenues for the exploration of host-schistosome interactions and offer a potential mechanism by which some vaccine antigens exert their protective efficacy. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  17. Indomethacin decreases gastroduodenal mucosal bicarbonate secretion in humans

    DEFF Research Database (Denmark)

    Mertz-Nielsen, A; Hillingsø, Jens; Bukhave, K

    1995-01-01

    BACKGROUND: Cyclooxygenase inhibitors reduce mucosal bicarbonate secretion in the duodenum, but the evidence for their effect on bicarbonate secretion in the stomach remains controversial. We have, therefore, studied how indomethacin influences gastroduodenal bicarbonate secretion and luminal...... healthy volunteers. Bicarbonate and PGE2 were measured in the gastroduodenal effluents by back-titration and radioimmunoassay, respectively. RESULTS: Vagal stimulation and duodenal luminal acidification (0.1 M HCl; 20 ml; 5 min) increased gastroduodenal bicarbonate secretion (p ... markedly inhibited both basal and stimulated gastric and duodenal mucosal bicarbonate secretion, and this reduction was similar to the degree of cyclooxygenase inhibition estimated by the luminal release of PGE2 (p

  18. Direct visualization of secretion from single bovine adrenal chromaffin cells by laser-induced native fluorescence imaging microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tong, W.; Yeung, E.S. [Ames Laboratory---USDOE and Department of Chemistry, Iowa State University, Ames, Iowa 50011 (United States)

    1998-03-01

    Direct visualization of the secretion process of individual bovine adrenal chromaffin cells was achieved with laser-induced native fluorescence imaging microscopy. By monitoring the native fluorescence of catecholamines excited by the 275 nm laser line with an intensified charge-coupled-device (CCD) camera, we obtained good temporal and spatial resolution simultaneously without using additional fluorescent probes. Large variations were found among individual cells in terms of the amounts of catecholamines secreted and the rates of secretion. Different regions of a cell also behave differently during the secretion process. However, the degree of this local heterogeneity is smaller than in neurons and neuralgia. The influence of deep-ultraviolet (UV) laser excitation on cells is also discussed. This quantitative imaging technique provides a useful noninvasive approach for the study of dynamic cellular changes and the understanding of the molecular mechanisms of secretory processes. {copyright} {ital 1998} {ital Society for Applied Spectroscopy}

  19. Effect of chenodeoxycholic acid and the bile acid sequestrant colesevelam on glucagon-like peptide-1 secretion

    DEFF Research Database (Denmark)

    Hansen, Morten; Scheltema, Matthijs J; Sonne, David P

    2016-01-01

    of the primary human bile acid, chenodeoxycholic acid (CDCA), and the BAS, colesevelam, instilled into the stomach, on plasma levels of GLP-1, glucose-dependent insulinotropic polypeptide, glucose, insulin, C-peptide, glucagon, cholecystokinin and gastrin as well as gastric emptying, gallbladder volume, appetite......AIMS: In patients with type 2 diabetes, rectal administration of bile acids increases glucagon-like peptide-1 (GLP-1) secretion and reduces plasma glucose. In addition, oral bile acid sequestrants (BASs) reduce blood glucose by an unknown mechanism. In this study we evaluated the effects......, and delayed gastric emptying. We speculate that bile acid-induced activation of TGR5 on L cells increases GLP-1 secretion, which in turn may result in amplification of glucose-stimulated insulin secretion. Furthermore our data suggest that colesevelam does not have an acute effect on GLP-1 secretion in humans....

  20. The effects of E and A prostaglandins on gastric mucosal blood flow and acid secretion in the rat

    Science.gov (United States)

    Main, I. H. M.; Whittle, B. J. R.

    1973-01-01

    1. The effects of prostaglandins E1, E2, A1 and A2 on gastric acid secretion and mucosal blood flow were studied by means of a [14C]-aniline clearance technique in the anaesthetized rat. 2. During intravenous administration of these prostaglandins, in doses which almost completely inhibited pentagastrin- and histamine-induced acid secretion, a fall in clearance was observed. 3. Clearance per unit acid secretion increased during prostaglandin administration, precluding a primary reduction in mucosal blood flow as the mechanism of the antisecretory action. 4. Prostaglandins increased clearance during basal secretion, indicating a direct vasodilator effect on the gastric mucosa. 5. The possibility that endogenous prostaglandins contribute to functional vasodilatation in the gastric mucosa and that exogenous prostaglandins may be of clinical value in the treatment of peptic ulcer is discussed. PMID:4149696

  1. EFFECTS OF SECRETABLE PLACENTAL FACTORS UPON SECRETION OF CYTOKINES BY THP-1 MONOCYTE-LIKE CELLS

    Directory of Open Access Journals (Sweden)

    Ya. S. Onokhina

    2013-01-01

    Full Text Available Abstract. Мonocytes in feto-placental circulation are exposed to factors secreted by placental tissue. These factors influence monocyte functions in pregnancy. In present study, an in vitro model (monocyte-like THP-1 cells was used for assessing effects of soluble placental factors obtained from women with physiological pregnancies, or preeclampsia cases. The following effects of placental factors were revealed: increased secretion of VEGF by THP-1 cells along with decreased secretion of IL-6, IL-8 and MCP-1 under the influence of placental factors from the I. trimester of pregnancy in comparison with III. trimester. Secretion of IL-6 and MCP-1 by THP-1 cells was increased, and secretion of soluble TNFRII was decreased upon co-cultivation with soluble placental factors from the women with preeclampsia, as compared with placental products from physiological pregnancies.The work is supported by grants ГК № 02.740.11.0711 from Ministry of Education and Science, and НШ-3594.2010.7 grant from the President of Russian Federation.

  2. TALK-1 reduces delta-cell endoplasmic reticulum and cytoplasmic calcium levels limiting somatostatin secretion

    Directory of Open Access Journals (Sweden)

    Nicholas C. Vierra

    2018-03-01

    mechanisms that control glucagon secretion. Keywords: Two-pore domain K+ channel, KCNK16, Paracrine, Islet, Endoplasmic reticulum, Hormone secretion

  3. The role of jasmonates in floral nectar secretion.

    Science.gov (United States)

    Radhika, Venkatesan; Kost, Christian; Boland, Wilhelm; Heil, Martin

    2010-02-19

    Plants produce nectar in their flowers as a reward for their pollinators and most of our crops depend on insect pollination, but little is known on the physiological control of nectar secretion. Jasmonates are well-known for their effects on senescence, the development and opening of flowers and on plant defences such as extrafloral nectar. Their role in floral nectar secretion has, however, not been explored so far. We investigated whether jasmonates have an influence on floral nectar secretion in oil-seed rape, Brassica napus. The floral tissues of this plant produced jasmonic acid (JA) endogenously, and JA concentrations peaked shortly before nectar secretion was highest. Exogenous application of JA to flowers induced nectar secretion, which was suppressed by treatment with phenidone, an inhibitor of JA synthesis. This effect could be reversed by additional application of JA. Jasmonoyl-isoleucine and its structural mimic coronalon also increased nectar secretion. Herbivory or addition of JA to the leaves did not have an effect on floral nectar secretion, demonstrating a functional separation of systemic defence signalling from reproductive nectar secretion. Jasmonates, which have been intensively studied in the context of herbivore defences and flower development, have a profound effect on floral nectar secretion and, thus, pollination efficiency in B. napus. Our results link floral nectar secretion to jasmonate signalling and thereby integrate the floral nectar secretion into the complex network of oxylipid-mediated developmental processes of plants.

  4. The role of jasmonates in floral nectar secretion.

    Directory of Open Access Journals (Sweden)

    Venkatesan Radhika

    Full Text Available Plants produce nectar in their flowers as a reward for their pollinators and most of our crops depend on insect pollination, but little is known on the physiological control of nectar secretion. Jasmonates are well-known for their effects on senescence, the development and opening of flowers and on plant defences such as extrafloral nectar. Their role in floral nectar secretion has, however, not been explored so far. We investigated whether jasmonates have an influence on floral nectar secretion in oil-seed rape, Brassica napus. The floral tissues of this plant produced jasmonic acid (JA endogenously, and JA concentrations peaked shortly before nectar secretion was highest. Exogenous application of JA to flowers induced nectar secretion, which was suppressed by treatment with phenidone, an inhibitor of JA synthesis. This effect could be reversed by additional application of JA. Jasmonoyl-isoleucine and its structural mimic coronalon also increased nectar secretion. Herbivory or addition of JA to the leaves did not have an effect on floral nectar secretion, demonstrating a functional separation of systemic defence signalling from reproductive nectar secretion. Jasmonates, which have been intensively studied in the context of herbivore defences and flower development, have a profound effect on floral nectar secretion and, thus, pollination efficiency in B. napus. Our results link floral nectar secretion to jasmonate signalling and thereby integrate the floral nectar secretion into the complex network of oxylipid-mediated developmental processes of plants.

  5. Secretion systems and signal exchange between nitrogen-fixing rhizobia and legumes.

    Science.gov (United States)

    Nelson, Matthew S; Sadowsky, Michael J

    2015-01-01

    The formation of symbiotic nitrogen-fixing nodules on the roots and/or stem of leguminous plants involves a complex signal exchange between both partners. Since many microorganisms are present in the soil, legumes and rhizobia must recognize and initiate communication with each other to establish symbioses. This results in the formation of nodules. Rhizobia within nodules exchange fixed nitrogen for carbon from the legume. Symbiotic relationships can become non-beneficial if one partner ceases to provide support to the other. As a result, complex signal exchange mechanisms have evolved to ensure continued, beneficial symbioses. Proper recognition and signal exchange is also the basis for host specificity. Nodule formation always provides a fitness benefit to rhizobia, but does not always provide a fitness benefit to legumes. Therefore, legumes have evolved a mechanism to regulate the number of nodules that are formed, this is called autoregulation of nodulation. Sequencing of many different rhizobia have revealed the presence of several secretion systems - and the Type III, Type IV, and Type VI secretion systems are known to be used by pathogens to transport effector proteins. These secretion systems are also known to have an effect on host specificity and are a determinant of overall nodule number on legumes. This review focuses on signal exchange between rhizobia and legumes, particularly focusing on the role of secretion systems involved in nodule formation and host specificity.

  6. Tec-kinase-mediated phosphorylation of fibroblast growth factor 2 is essential for unconventional secretion.

    Science.gov (United States)

    Ebert, Antje D; Laussmann, Mareike; Wegehingel, Sabine; Kaderali, Lars; Erfle, Holger; Reichert, Jürgen; Lechner, Johannes; Beer, Hans-Dietmar; Pepperkok, Rainer; Nickel, Walter

    2010-06-01

    Fibroblast growth factor 2 (FGF2) is a potent mitogen that is exported from cells by an endoplasmic reticulum (ER)/Golgi-independent mechanism. Unconventional secretion of FGF2 occurs by direct translocation across plasma membranes, a process that depends on the phosphoinositide phosphatidylinositol 4,5-biphosphate (PI(4,5)P(2)) at the inner leaflet as well as heparan sulfate proteoglycans at the outer leaflet of plasma membranes; however, additional core and regulatory components of the FGF2 export machinery have remained elusive. Here, using a highly effective RNAi screening approach, we discovered Tec kinase as a novel factor involved in unconventional secretion of FGF2. Tec kinase does not affect FGF2 secretion by an indirect mechanism, but rather forms a heterodimeric complex with FGF2 resulting in phosphorylation of FGF2 at tyrosine 82, a post-translational modification shown to be essential for FGF2 membrane translocation to cell surfaces. Our findings suggest a crucial role for Tec kinase in regulating FGF2 secretion under various physiological conditions and, therefore, provide a new perspective for the development of a novel class of antiangiogenic drugs targeting the formation of the FGF2/Tec complex.

  7. Developmental and nutritional regulation of isoflavone secretion from soybean roots.

    Science.gov (United States)

    Sugiyama, Akifumi; Yamazaki, Yumi; Yamashita, Kazuaki; Takahashi, Seiji; Nakayama, Toru; Yazaki, Kazufumi

    2016-01-01

    Isoflavones play important roles in plant-microbe interactions in rhizospheres. Soybean roots secrete daidzein and genistein to attract rhizobia. Despite the importance of isoflavones in plant-microbe interactions, little is known about the developmental and nutritional regulation of isoflavone secretion from soybean roots. In this study, soybeans were grown in hydroponic culture, and isoflavone contents in tissues, isoflavone secretion from the roots, and the expression of isoflavone conjugates hydrolyzing beta-glucosidase (ICHG) were investigated. Isoflavone contents did not show strong growth-dependent changes, while secretion of daidzein from the roots dramatically changed, with higher secretion during vegetative stages. Coordinately, the expression of ICHG also peaked at vegetative stages. Nitrogen deficiency resulted in 8- and 15-fold increases in secretion of daidzein and genistein, respectively, with no induction of ICHG. Taken together, these results suggest that large amounts of isoflavones were secreted during vegetative stages via the hydrolysis of (malonyl)glucosides with ICHG.

  8. Syntaxin-4 is essential for IgE secretion by plasma cells

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Arman; DeCourcey, Joseph; Larbi, Nadia Ben [Immunomodulation Group, School of Biotechnology, Dublin City University (Ireland); Loughran, Sinéad T.; Walls, Dermot [School of Biotechnology and National Centre for Sensor Research, Dublin City University (Ireland); Loscher, Christine E., E-mail: christine.loscher@dcu.ie [Immunomodulation Group, School of Biotechnology, Dublin City University (Ireland)

    2013-10-11

    Highlights: •Knock-down of syntaxin-4 in U266 plasma cells resulted in reduction of IgE secretion. •Knock-down of syntaxin-4 also leads to the accumulation of IgE in the cell. •Immuno-fluorescence staining shows co-localisation of IgE and syntaxin-4 in U266 cells. •Findings suggest a critical requirement for syntaxin-4 in IgE secretion from plasma cells. -- Abstract: The humoral immune system provides a crucial first defense against the invasion of microbial pathogens via the secretion of antigen specific immunoglobulins (Ig). The secretion of Ig is carried out by terminally differentiated B-lymphocytes called plasma cells. Despite the key role of plasma cells in the immune response, the mechanisms by which they constitutively traffic large volumes of Ig out of the cell is poorly understood. The involvement of Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins in the regulation of protein trafficking from cells has been well documented. Syntaxin-4, a member of the Qa SNARE syntaxin family has been implicated in fusion events at the plasma membrane in a number of cells in the immune system. In this work we show that knock-down of syntaxin-4 in the multiple myeloma U266 human plasma cell line results in a loss of IgE secretion and accumulation of IgE within the cells. Furthermore, we show that IgE co-localises with syntaxin-4 in U266 plasma cells suggesting direct involvement in secretion at the plasma membrane. This study demonstrates that syntaxin-4 plays a critical role in the secretion of IgE from plasma cells and sheds some light on the mechanisms by which these cells constitutively traffic vesicles to the surface for secretion. An understanding of this machinery may be beneficial in identifying potential therapeutic targets in multiple myeloma and autoimmune disease where over-production of Ig leads to severe pathology in patients.

  9. Poisons, toxungens, and venoms: redefining and classifying toxic biological secretions and the organisms that employ them.

    Science.gov (United States)

    Nelsen, David R; Nisani, Zia; Cooper, Allen M; Fox, Gerad A; Gren, Eric C K; Corbit, Aaron G; Hayes, William K

    2014-05-01

    Despite extensive study of poisonous and venomous organisms and the toxins they produce, a review of the literature reveals inconsistency and ambiguity in the definitions of 'poison' and 'venom'. These two terms are frequently conflated with one another, and with the more general term, 'toxin.' We therefore clarify distinctions among three major classes of toxins (biological, environmental, and anthropogenic or man-made), evaluate prior definitions of venom which differentiate it from poison, and propose more rigorous definitions for poison and venom based on differences in mechanism of delivery. We also introduce a new term, 'toxungen', thereby partitioning toxic biological secretions into three categories: poisons lacking a delivery mechanism, i.e. ingested, inhaled, or absorbed across the body surface; toxungens delivered to the body surface without an accompanying wound; and venoms, delivered to internal tissues via creation of a wound. We further propose a system to classify toxic organisms with respect to delivery mechanism (absent versus present), source (autogenous versus heterogenous), and storage of toxins (aglandular versus glandular). As examples, a frog that acquires toxins from its diet, stores the secretion within cutaneous glands, and transfers the secretion upon contact or ingestion would be heteroglandular-poisonous; an ant that produces its own toxins, stores the secretion in a gland, and sprays it for defence would be autoglandular-toxungenous; and an anemone that produces its own toxins within specialized cells that deliver the secretion via a penetrating wound would be autoaglandular-venomous. Adoption of our scheme should benefit our understanding of both proximate and ultimate causes in the evolution of these toxins. © 2013 The Authors. Biological Reviews © 2013 Cambridge Philosophical Society.

  10. Reelin secreted by GABAergic neurons regulates glutamate receptor homeostasis.

    Directory of Open Access Journals (Sweden)

    Cecilia Gonzalez Campo

    Full Text Available BACKGROUND: Reelin is a large secreted protein of the extracellular matrix that has been proposed to participate to the etiology of schizophrenia. During development, reelin is crucial for the correct cytoarchitecture of laminated brain structures and is produced by a subset of neurons named Cajal-Retzius. After birth, most of these cells degenerate and reelin expression persists in postnatal and adult brain. The phenotype of neurons that bind secreted reelin and whether the continuous secretion of reelin is required for physiological functions at postnatal stages remain unknown. METHODOLOGY/PRINCIPAL FINDINGS: Combining immunocytochemical and pharmacological approaches, we first report that two distinct patterns of reelin expression are present in cultured hippocampal neurons. We show that in hippocampal cultures, reelin is secreted by GABAergic neurons displaying an intense reelin immunoreactivity (IR. We demonstrate that secreted reelin binds to receptors of the lipoprotein family on neurons with a punctate reelin IR. Secondly, using calcium imaging techniques, we examined the physiological consequences of reelin secretion blockade. Blocking protein secretion rapidly and reversibly changes the subunit composition of N-methyl-D-aspartate glutamate receptors (NMDARs to a predominance of NR2B-containing NMDARs. Addition of recombinant or endogenously secreted reelin rescues the effects of protein secretion blockade and reverts the fraction of NR2B-containing NMDARs to control levels. Therefore, the continuous secretion of reelin is necessary to control the subunit composition of NMDARs in hippocampal neurons. CONCLUSIONS/SIGNIFICANCE: Our data show that the heterogeneity of reelin immunoreactivity correlates with distinct functional populations: neurons synthesizing and secreting reelin and/or neurons binding reelin. Furthermore, we show that continuous reelin secretion is a strict requirement to maintain the composition of NMDARs. We propose

  11. Secretive eating among youth with overweight or obesity.

    Science.gov (United States)

    Kass, Andrea E; Wilfley, Denise E; Eddy, Kamryn T; Boutelle, Kerri N; Zucker, Nancy; Peterson, Carol B; Le Grange, Daniel; Celio-Doyle, Angela; Goldschmidt, Andrea B

    2017-07-01

    Secretive eating, characterized by eating privately to conceal being seen, may reflect eating- and/or body-related shame, be associated with depression, and correlate with binge eating, which predicts weight gain and eating disorder onset. Increasing understanding of secretive eating in youth may improve weight status and reduce eating disorder risk. This study evaluated the prevalence and correlates of secretive eating in youth with overweight or obesity. Youth (N = 577) presented to five research/clinical institutions. Using a cross-sectional design, secretive eating was evaluated in relation to eating-related and general psychopathology via linear and logistic regression analyses. Secretive eating was endorsed by 111 youth, who were, on average, older than youth who denied secretive eating (mean age = 12.07 ± 2.83 versus 10.97 ± 2.31). Controlling for study site and age, youth who endorsed secretive eating had higher eating-related psychopathology and were more likely to endorse loss of control eating and purging than their counterparts who did not endorse secretive eating. Groups did not differ in excessive exercise or behavioral problems. Dietary restraint and purging were elevated among adolescents (≥13y) but not children (<13y) who endorsed secretive eating; depression was elevated among children, but not adolescents, who endorsed secretive eating. Secretive eating may portend heightened risk for eating disorders, and correlates of secretive eating may differ across pediatric development. Screening for secretive eating may inform identification of problematic eating behaviors, and understanding factors motivating secretive eating may improve intervention tailoring. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Pancreatic network control of glucagon secretion and counterregulation.

    Science.gov (United States)

    Farhy, Leon S; McCall, Anthony L

    2009-01-01

    Glucagon counterregulation (GCR) is a key protection against hypoglycemia compromised in insulinopenic diabetes by an unknown mechanism. In this work, we present an interdisciplinary approach to the analysis of the GCR control mechanisms. Our results indicate that a pancreatic network which unifies a few explicit interactions between the major islet peptides and blood glucose (BG) can replicate the normal GCR axis and explain its impairment in diabetes. A key and novel component of this network is an alpha-cell auto-feedback, which drives glucagon pulsatility and mediates triggering of pulsatile GCR by hypoglycemia via a switch-off of the beta-cell suppression of the alpha-cells. We have performed simulations based on our models of the endocrine pancreas which explain the in vivo GCR response to hypoglycemia of the normal pancreas and the enhancement of defective pulsatile GCR in beta-cell deficiency by switch-off of intrapancreatic alpha-cell suppressing signals. The models also predicted that reduced insulin secretion decreases and delays the GCR. In conclusion, based on experimental data we have developed and validated a model of the normal GCR control mechanisms and their dysregulation in insulin deficient diabetes. One advantage of this construct is that all model components are clinically measurable, thereby permitting its transfer, validation, and application to the study of the GCR abnormalities of the human endocrine pancreas in vivo.

  13. Antidiarrheal activity of wood creosote: inhibition of muscle contraction and enterotoxin-induced fluid secretion in rabbit small intestine.

    Science.gov (United States)

    Ogata, N; Shibata, T

    2001-01-01

    Wood creosote has long been used as an antidiarrheal agent, but its mechanism of action is not well understood. To elucidate the mechanism of its antidiarrheal activity, we have addressed questions whether it inhibits fluid secretion induced by Escherichia coli heat-stable enterotoxin (STa) in rabbit jejunum in vivo, and whether it inhibits muscle contraction of isolated rabbit ileum ex vivo. Wood creosote (10-100 mg/l) instilled in a ligated loop of jejunum inhibited STa-induced fluid secretion (p creosote is attributable to its antisecretory and antimotility effects. Copyright 2001 S. Karger AG, Basel

  14. Proteomics of protein secretion by Aggregatibacter actinomycetemcomitans.

    Directory of Open Access Journals (Sweden)

    Vincent Zijnge

    Full Text Available The extracellular proteome (secretome of periodontitis-associated bacteria may constitute a major link between periodontitis and systemic diseases. To obtain an overview of the virulence potential of Aggregatibacter actinomycetemcomitans, an oral and systemic human pathogen implicated in aggressive periodontitis, we used a combined LC-MS/MS and bioinformatics approach to characterize the secretome and protein secretion pathways of the rough-colony serotype a strain D7S. LC-MS/MS revealed 179 proteins secreted during biofilm growth. Further to confirming the release of established virulence factors (e.g. cytolethal distending toxin [CDT], and leukotoxin [LtxA], we identified additional putative virulence determinants in the secretome. These included DegQ, fHbp, LppC, Macrophage infectivity protein (MIP, NlpB, Pcp, PotD, TolB, and TolC. This finding indicates that the number of extracellular virulence-related proteins is much larger than previously demonstrated, which was also supported by in silico analysis of the strain D7S genome. Moreover, our LC-MS/MS and in silico data revealed that at least Type I, II, and V secretion are actively used to excrete proteins directly into the extracellular space, or via two-step pathways involving the Sec/Tat systems for transport across the inner membrane, and outer membrane factors, secretins and auto-transporters, respectively for delivery across the outer membrane. Taken together, our results provide a molecular basis for further elucidating the role of A. actinomycetemcomitans in periodontal and systemic diseases.

  15. Pentagon's secret report about climate change

    International Nuclear Information System (INIS)

    Schwartz, P.

    2006-01-01

    This book reveals the content of a secret report ordered by the department of defense of the Pentagon which aims at foreseeing the possible consequences of a rapid climatic change on the security of the USA. The report is based on the most recent studies about the general climate conditions at the worldwide scale. They foresee for 2010 a fast cooling following several years of increasing warming up. A realistic detailed scenario of the geopolitical consequences of this change is made: floods, conflicts, populations migration, lack of drinkable water, starvation, generalized riots etc. (J.S.)

  16. MECHANISMS OF BACTERIAL POLYHOSTALITY

    Directory of Open Access Journals (Sweden)

    Markova Yu.A.

    2007-12-01

    Full Text Available In the review data about factors of pathogenicity of the bacteria, capable to amaze both animals, and a plant are collected. Such properties of microorganisms as adhesion, secretion of some enzymes, mobility, a phenomenon of cooperative sensitivity - play an essential role at defeat of different organisms. They are used for many universal offensive strategy overcoming protection of an organism, irrespective of its evolutionary origin. Studying of these mechanisms, will allow to provide new approaches to monitoring illnesses.

  17. Proteases induce secretion of collagenase and plasminogen activator by fibroblasts

    Energy Technology Data Exchange (ETDEWEB)

    Werb, Z.; Aggeler, J.

    1978-04-01

    We have observed that treatment of rabbit synovial fibroblasts with proteolytic enzymes can induce secretion of collagenase (EC 3.4.24.7) and plasminogen activator (EC 3.4.21.-). Cells treated for 2 to 24 hr with plasmin, trypsin, chymotrypsin, pancreatic elastase, papain, bromelain, thermolysin, or ..cap alpha..-protease but not with thrombin or neuraminidase secreted detectable amounts of collagenase within 16 to 48 hr. Treatment of fibroblasts with trypsin also induced secretion of plasminogen activator. Proteases initiated secretion of collagenase (up to 20 units per 10/sup 6/ cells per 24 hr) only when treatment produced decreased cell adhesion. Collagenase production did not depend on continued presence of proteolytic activity or on subsequent cell adhesion, spreading, or proliferation. Routine subculturing with crude trypsin also induced collagenase secretion by cells. Secretion of collagenase was prevented and normal spreading was obtained if the trypsinized cells were placed into medium containing fetal calf serum. Soybean trypsin inhibitor, ..cap alpha../sub 1/-antitrypsin, bovine serum albumin, collagen, and fibronectin did not inhibit collagenase production. Although proteases that induced collagenase secretion also removed surface glycoprotein, the kinetics of induction of cell protease secretion were different from those for removal of fibronectin. Physiological inducers of secretion of collagenase and plasminogen activator by cells have not been identified. These results suggest that extracellular proteases in conjunction with plasma proteins may govern protease secretion by cells.

  18. Exposure to static magnetic fields increases insulin secretion in rat INS-1 cells by activating the transcription of the insulin gene and up-regulating the expression of vesicle-secreted proteins.

    Science.gov (United States)

    Mao, Libin; Wang, Huiqin; Ma, Fenghui; Guo, Zhixia; He, Hongpeng; Zhou, Hao; Wang, Nan

    2017-08-01

    To evaluate the effect of static magnetic fields (SMFs) on insulin secretion and explore the mechanisms underlying exposure to SMF-induced insulin secretion in rat insulinoma INS-1 cells. INS-1 cells were exposed to a 400 mT SMF for 72 h, and the proliferation of INS-1 cells was detected by (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The secretion of insulin was measured with an enzyme linked immunosorbent assays (ELISA), the expression of genes was detected by real-time PCR, and the expression of proteins was measured by Western blotting. Exposure to an SMF increased the expression and secretion of insulin by INS-1 cells but did not affect cell proliferation. Moreover, SMF exposure up-regulated the expression of several pancreas-specific transcriptional factors. Specifically, the activity of the rat insulin promoter was enhanced in INS-1 cells exposed to an SMF, and the expression levels of synaptosomal-associated protein 25 (SNAP-25) and syntaxin-1A were up-regulated after exposure to an SMF. SMF exposure can promote insulin secretion in rat INS-1 cells by activating the transcription of the insulin gene and up-regulating the expression of vesicle-secreted proteins.

  19. Weapons of Mass Secretion : The Type III Secretion System of Shigella flexneri

    NARCIS (Netherlands)

    Sani, Musa

    2007-01-01

    In bacteria that are pathogenic for animals, type III secretion systems allow extracellular bacteria adhering to the surface of a host cell to inject specialized proteins across the plasma membrane. The injected proteins subvert the functioning of the aggressed cell or destroy its communications,

  20. Trade Secret Law and Information Systems: Can Your Students Keep a Secret?

    Science.gov (United States)

    Willey, Lorrie; Ford, Janet C.; White, Barbara Jo; Clapper, Danial L.

    2011-01-01

    The impact of intellectual property (IP) law on information systems (IS) professionals in business cannot be overstated. The IS 2010 model curriculum guidelines for undergraduate IS programs stress the importance of information security and knowledge about IP. While copyright and patents are the most well-known types of IP, another, trade secrets,…

  1. Secretion of clostridium cellulase by E. coli

    Science.gov (United States)

    Yu, Ida Kuo

    1998-01-01

    A gene, encoding an endocellulase from a newly isolated mesophilic Clostridium strain IY-2 which can digest bamboo fibers, cellulose, rice straw, and sawdust, was isolated by shotgun cloning in an E. coli expression plasmid pLC2833. E. coli positive clones were selected based on their ability to hydrolyze milled bamboo fibers and cellulose present in agar plates. One clone contained a 2.8 kb DNA fragment that was responsible for cellulase activity. Western blot analyses indicated that the positive clone produced a secreted cellulase with a mass of about 58,000 daltons that was identical in size to the subunit of one of the three major Clostridium cellulases. The products of cellulose digestion by this cloned cellulase were cellotetraose and soluble higher polymers. The cloned DNA contained signal sequences capable of directing the secretion of heterologous proteins from an E. coli host. The invention describes a bioprocess for the treatment of cellulosic plant materials to produce cellular growth substrates and fermentation end products suitable for production of liquid fuels, solvents, and acids.

  2. Prolactin secretion: the impact of dynamic studies

    International Nuclear Information System (INIS)

    L'Hermite, M.; Degueldre, M.; Caufriez, A.; Delvoye, P.; Robyn, C.

    1975-01-01

    Human prolactin blood levels were determined by radioimmunoassay in basal condition and in response to various inhibiting and/or stimulating agents (levodopa, water overload, insulinic hypoglycaemia, synthetic TRH, sulpiride) in cases of disturbed hypothalamo-pituitary axis (failure to lactate, prolactin-secreting pituitary adenomas, acromegaly, other pituitary tumours, clinical panhypopituitarism). A blunted prolactin response to suckling was evidenced in 2 post-partum women who were unable to breast feed. Hyperprolactinaemia, whether related to the existence of a prolactin-producing adenoma or not was associated with the disappearance of the normal circadian pattern of prolactin secretion and with a blunted relative response to TRH; the latter phenomenon occurred also in acromegaly regardless of the basal prolactinaemia, and during the last trimester of pregnancy. Water overload was unsuccessful to suppress prolactin during the last trimester of pregnancy while the acute administration of levodopa was quite effective in about half of the patients with pituitary tumour. Therefore none of the dynamic tests presently studied allowed to attribute a hyperprolactinaemia to a pituitary tumour rather than to a functional disturbance. On the contrary, stimulation tests can help to locate the level of a defect in cases of hypopituitarism [fr

  3. Loose excitation-secretion coupling in astrocytes.

    Science.gov (United States)

    Vardjan, Nina; Parpura, Vladimir; Zorec, Robert

    2016-05-01

    Astrocytes play an important housekeeping role in the central nervous system. Additionally, as secretory cells, they actively participate in cell-to-cell communication, which can be mediated by membrane-bound vesicles. The gliosignaling molecules stored in these vesicles are discharged into the extracellular space after the vesicle membrane fuses with the plasma membrane. This process is termed exocytosis, regulated by SNARE proteins, and triggered by elevations in cytosolic calcium levels, which are necessary and sufficient for exocytosis in astrocytes. For astrocytic exocytosis, calcium is sourced from the intracellular endoplasmic reticulum store, although its entry from the extracellular space contributes to cytosolic calcium dynamics in astrocytes. Here, we discuss calcium management in astrocytic exocytosis and the properties of the membrane-bound vesicles that store gliosignaling molecules, including the vesicle fusion machinery and kinetics of vesicle content discharge. In astrocytes, the delay between the increase in cytosolic calcium activity and the discharge of secretions from the vesicular lumen is orders of magnitude longer than that in neurons. This relatively loose excitation-secretion coupling is likely tailored to the participation of astrocytes in modulating neural network processing. © 2015 Wiley Periodicals, Inc.

  4. Gastric Lipase Secretion in Children with Gastritis

    Directory of Open Access Journals (Sweden)

    Krystyna Sztefko

    2013-07-01

    Full Text Available Gastric lipase is one of the prepancreatic lipases found in some mammalian species and in humans. Our knowledge of the hormonal regulation of gastric lipase secretion in children and adolescents is still very limited. The aim of this study was to compare the activity of human gastric lipase (HGL in gastric juice in healthy adolescents and in patients with gastritis. The adolescents were allocated to three groups: the first including patients with Helicobacter pylori gastritis (HPG; n = 10, the second including patients with superficial gastritis caused by pathogens other than H. pylori (non-HPG; n = 14 and the control group including healthy adolescents (n = 14. Activity of HGL was measured in gastric juice collected during endoscopy. Plasma concentrations of cholecystokinin (CCK, glucagon-like peptide-1 (GLP-1 and glucose-dependent insulinotropic peptide (GIP were measured in all adolescents. Activity of HGL in the non-HPG group was significantly lower than in the HPG group (p < 0.005 and the control group (p < 0.005. Mean plasma GIP levels in the control group were lower than in the non-HPG group (p < 0.003 and the HPG group (p < 0.01. We conclude that the regulation of HGL secretion by GLP-1 and CCK is altered in patients with gastritis. Moreover, GIP is a potent controller of HGL activity, both in healthy subjects and in patients with gastritis.

  5. The Smart Grid - A saucerful of secrets?

    International Nuclear Information System (INIS)

    Wissner, Matthias

    2011-01-01

    To many, a lot of secrets are at the bottom of the often-cited catchphrase 'Smart Grid'. This article gives an overview of the options that information and communication technology (ICT) offers for the restructuring and modernisation of the German power system, in particular with a view towards its development into a Smart Grid and thus tries to reveal these secrets. After a short outline on the development of ICT in terms of technology types and their availability, the further analysis highlights upcoming challenges in all parts of the power value chain and possible solutions for these challenges through the intensified usage of ICT applications. They are examined with regard to their effectiveness and efficiency in the fields of generation, transmission, distribution and supply. Finally, potential obstacles that may defer the introduction of ICT into the power system are shown. The analysis suggests that if certain hurdles are taken, the huge potential of ICT can create additional value in various fields of the whole power value chain. This ranges from increased energy efficiency and the more sophisticated integration of decentralised (renewable) energy plants to a higher security of supply and more efficient organisation of market processes. The results are true for the German power market but can in many areas also be transferred to other industrialised nations with liberalised power markets.

  6. Exocrine pancreas glutamate secretion help to sustain enterocyte nutritional needs under protein restriction.

    Science.gov (United States)

    Araya, S; Kuster, E; Gluch, D; Mariotta, L; Lutz, C; Reding, T V; Graf, R; Verrey, F; Camargo, S M R

    2018-04-01

    Glutamine (Gln) is the most concentrated amino acid in blood and considered conditionally essential. Its requirement is increased during physiological stress, such as malnutrition or illness, despite its production by muscle and other organs. In the malnourished state, Gln has been suggested to have a trophic effect on the exocrine pancreas and small intestine. However, the Gln transport capacity, the functional relationship of these two organs, and the potential role of the Gln-glutamate (Glu) cycle are unknown. We observed that pancreatic acinar cells express lower levels of Glu than Gln transporters. Consistent with this expression pattern, the rate of Glu influx into acinar cells was approximately sixfold lower than that of Gln. During protein restriction, acinar cell glutaminase expression was increased and Gln accumulation was maintained. Moreover, Glu secretion by acinar cells into pancreatic juice and thus into the lumen of the small intestine was maintained. In the intestinal lumen, Glu absorption was preserved and Glu dehydrogenase expression was augmented, potentially providing the substrates for increasing energy production via the TCA cycle. Our findings suggest that one mechanism by which Gln exerts a positive effect on exocrine pancreas and small intestine involves the Gln metabolism in acinar cells and the secretion of Glu into the small intestine lumen. The exocrine pancreas acinar cells not only avidly accumulate Gln but metabolize Gln to generate energy and to synthesize Glu for secretion in the pancreatic juice. Secreted Glu is suggested to play an important role during malnourishment in sustaining small intestinal homeostasis. NEW & NOTEWORTHY Glutamine (Gln) has been suggested to have a trophic effect on exocrine pancreas and small intestine in malnourished states, but the mechanism is unknown. In this study, we suggest that this trophic effect derives from an interorgan relationship between exocrine pancreas and small intestine for Gln

  7. Platelet aggregation, secretion, and coagulation changes in children with asthma.

    Science.gov (United States)

    Buyukyilmaz, Gonul; Soyer, Ozge U; Buyuktiryaki, Betul; Alioglu, Bulent; Dallar, Yildiz

    2014-10-01

    The chronic inflammation in asthma evolves by cells including eosinophils, mast cells and lymphocytes. Despite their principal function in hemostasis, platelets contribute to pathogenesis of asthma that activation of platelets occurs following antigen provocation and during asthma attack. Our aim was to evaluate the platelet functions and other hemostatic features of children with asthma, both during symptom-free period and asthma attack. We enrolled patients with asthma attack (n = 33), mild intermittent asthma (n = 18), mild persistent asthma (n = 15) and healthy children (n = 20). Demographic characteristics and disease-related features were noted. Platelet aggregation and secretion tests (expressed as ATP release) were performed by lumiaggregometer method by stimulation with collagen, epinephrine, ADP, thrombin, ristocetin and arachidonic acid. Plasma levels of D-dimer, factor VIII (FVIII) and von Willebrand factor (vWF) were assessed. There were no differences in platelet aggregation induced by agonists between study groups. ATP release from platelets of patients with asthma exacerbation induced by ADP was lower compared with mild intermittent asthma (P asthma attack than mild intermittent (P = 0.039) and mild persistent asthma (P = 0.011) and controls (P = 0.018). vWF measurements were higher in children with asthma attack than other study groups (P = 0.001). However, FVIII was increased in patients with severe asthma attack. Asthma is a disease in which many immune cells play a role, one of which is the platelet. Distinctions in platelet secretion profiles and plasma levels of vWF and FVIII provide evidence that coagulation mechanisms might be critical for asthma pathogenesis.

  8. Deletion of GPR40 Impairs Glucose-Induced Insulin Secretion In Vivo in Mice Without Affecting Intracellular Fuel Metabolism in Islets

    Energy Technology Data Exchange (ETDEWEB)

    Alquier, Thierry; Peyot, Marie-Line; Latour, M. G.; Kebede, Melkam; Sorensen, Christina M.; Gesta, Stephane; Kahn, C. R.; Smith, Richard D.; Jetton, Thomas L.; Metz, Thomas O.; Prentki, Marc; Poitout, Vincent J.

    2009-11-01

    The G protein-coupled receptor GPR40 mediates fatty-acid potentiation of glucose-stimulated insulin secretion, but its contribution to insulin secretion in vivo and mechanisms of action remain uncertain. This study was aimed to ascertain whether GPR40 controls insulin secretion in vivo and modulates intracellular fuel metabolism in islets. We observed that glucose- and arginine-stimulated insulin secretion, assessed by hyperglycemic clamps, was decreased by approximately 60% in GPR40 knock-out (KO) fasted and fed mice, without changes in insulin sensitivity assessed by hyperinsulinemic-euglycemic clamps. Glucose and palmitate metabolism were not affected by GPR40 deletion. Lipid profiling revealed a similar increase in triglyceride and decrease in lysophosphatidylethanolamine species in WT and KO islets in response to palmitate. These results demonstrate that GPR40 regulates insulin secretion in vivo not only in response to fatty acids but also to glucose and arginine, without altering intracellular fuel metabolism.

  9. Structure of the mycobacterial ESX-5 type VII secretion system membrane complex by single-particle analysis.

    Science.gov (United States)

    Beckham, Katherine S H; Ciccarelli, Luciano; Bunduc, Catalin M; Mertens, Haydyn D T; Ummels, Roy; Lugmayr, Wolfgang; Mayr, Julia; Rettel, Mandy; Savitski, Mikhail M; Svergun, Dmitri I; Bitter, Wilbert; Wilmanns, Matthias; Marlovits, Thomas C; Parret, Annabel H A; Houben, Edith N G

    2017-04-10

    Mycobacteria are characterized by their impermeable outer membrane, which is rich in mycolic acids 1 . To transport substrates across this complex cell envelope, mycobacteria rely on type VII (also known as ESX) secretion systems 2 . In Mycobacterium tuberculosis, these ESX systems are essential for growth and full virulence and therefore represent an attractive target for anti-tuberculosis drugs 3 . However, the molecular details underlying type VII secretion are largely unknown, due to a lack of structural information. Here, we report the molecular architecture of the ESX-5 membrane complex from Mycobacterium xenopi determined at 13 Å resolution by electron microscopy. The four core proteins of the ESX-5 complex (EccB 5 , EccC 5 , EccD 5 and EccE 5 ) assemble with equimolar stoichiometry into an oligomeric assembly that displays six-fold symmetry. This membrane-associated complex seems to be embedded exclusively in the inner membrane, which indicates that additional components are required to translocate substrates across the mycobacterial outer membrane. Furthermore, the extended cytosolic domains of the EccC ATPase, which interact with secretion effectors, are highly flexible, suggesting an as yet unseen mode of substrate interaction. Comparison of our results with known structures of other bacterial secretion systems demonstrates that the architecture of type VII secretion system is fundamentally different, suggesting an alternative secretion mechanism.

  10. The effect of cimetidine on basal and stimulated pepsin secretion in the isolated whole stomach of the rat.

    Science.gov (United States)

    Bunce, K. T.; Grewal, M.; Parsons, M. E.

    1981-01-01

    1 The isolated stomach preparation of the immature rat has been used to study the stimulation and inhibition of pepsin secretion. 2 The isolated stomach secretes a basal level of pepsin. High concentrations (10(-3)M) of the H2-receptor antagonist, cimetidine, and the muscarinic receptor blocking drug, atropine, did not affect this secretion in a manner which was consistently of statistical significance. 3 Concentrations of histamine of 10(-5)M, 10(-4)M and 10(-3) M stimulated maximum levels of pepsin output of 126%, 155% and 299% respectively of control. There was no evidence that this secretion was secondary to the stimulation of acid secretion. 4 Cimetidine (10(-4)M and 10(-3)M) produced a dose-related inhibition of the pepsin output to 10(-3)M histamine, suggesting that histamine H2-receptors mediate this response. 5 Atropine (10(-3)M) had no effect on the pepsin response to 10(-3)M histamine, suggesting that muscarinic mechanisms play no part, even modulatory, in this secretion. PMID:6793118

  11. Molecular Diversity of Compounds from Pygidial Gland Secretions of Cave-Dwelling Ground Beetles: The First Evidence.

    Science.gov (United States)

    Vesović, Nikola; Ćurčić, Srećko; Vujisić, Ljubodrag; Nenadić, Marija; Krstić, Gordana; Perić-Mataruga, Vesna; Milosavljević, Slobodan; Antić, Dragan; Mandić, Boris; Petković, Matija; Vučković, Ivan; Marković, Đorđe; Vrbica, Maja; Ćurčić, Božidar; Makarov, Slobodan

    2015-06-01

    Three adult cave-dwelling ground beetle species were induced to discharge secretions of their pygidial glands into vials. Dichloromethane extraction was used to obtain the secretions. In total, 42 compounds were identified by GC/MS analysis. Pheggomisetes ninae contained 32 glandular compounds, Laemostenus (Pristonychus) punctatus 13, whereas Duvalius (Paraduvalius) milutini had nine compounds. Caproic, oleic, palmitic, and stearic acids were present in the samples of all analyzed species. Undecane was predominant in the extract of L. punctatus. Palmitic acid was the major component in the secretion of D. milutini. Finally, the most abundant compounds in P. ninae secretion were heptacosene and nonacosadienes. Herein, we present the first data on the identification of pygidial gland secretion components in both troglophilous and troglobite cave-dwelling ground beetles. Some compounds are reported for the first time in the secretions of ground beetles and other higher or lower taxa. The adaptation to underground life has not led to a reduction or changes in the chemical defense mechanism in the analyzed troglophilous and troglobitic Platyninae and Trechinae taxa.

  12. Secretion of flagellin by the LEE-encoded type III secretion system of enteropathogenic Escherichia coli

    Directory of Open Access Journals (Sweden)

    Kaparakis Maria

    2009-02-01

    Full Text Available Abstract Background Enteropathogenic Escherichia coli (EPEC is an attaching and effacing (A/E pathogen that possesses a type III secretion system (T3SS encoded within the locus of enterocyte effacement (LEE. The LEE is essential for A/E lesion formation and directs the secretion and translocation of multiple LEE-encoded and non-LEE encoded effector proteins into the cytosol of infected cells. In this study we used proteomics to compare proteins exported to the culture supernatant by wild type EPEC E2348/69, a ΔespADB mutant and a ΔescF T3SS mutant. Results We observed that flagellin was consistently and strongly present in the secretome of wild type EPEC and the ΔespADB mutant but present only weakly in the secretome of the ΔescF mutant. Given the ancestral relationship between the flagella export apparatus and virulence associated T3SSs, we investigated whether FliC could utilise the LEE-encoded T3SS for export. In the absence of a functional flagella export apparatus, we showed that FliC could be secreted by the LEE-encoded T3SS and stimulate (Toll-like receptor 5 TLR5 signalling but could not confer motility. Conclusion Since the secretion of FliC during A/E lesion formation would presumably be disadvantageous for the pathogen, we propose that virulence associated T3SSs and flagella T3SSs have evolved through a system of chaperones and complex regulatory pathways to be functional at different times to ensure that FliC secretion does not occur during T3SS effector translocation.

  13. Secretion of flagellin by the LEE-encoded type III secretion system of enteropathogenic Escherichia coli.

    Science.gov (United States)

    Badea, Luminita; Beatson, Scott A; Kaparakis, Maria; Ferrero, Richard L; Hartland, Elizabeth L

    2009-02-06

    Enteropathogenic Escherichia coli (EPEC) is an attaching and effacing (A/E) pathogen that possesses a type III secretion system (T3SS) encoded within the locus of enterocyte effacement (LEE). The LEE is essential for A/E lesion formation and directs the secretion and translocation of multiple LEE-encoded and non-LEE encoded effector proteins into the cytosol of infected cells. In this study we used proteomics to compare proteins exported to the culture supernatant by wild type EPEC E2348/69, a DeltaespADB mutant and a DeltaescF T3SS mutant. We observed that flagellin was consistently and strongly present in the secretome of wild type EPEC and the DeltaespADB mutant but present only weakly in the secretome of the DeltaescF mutant. Given the ancestral relationship between the flagella export apparatus and virulence associated T3SSs, we investigated whether FliC could utilise the LEE-encoded T3SS for export. In the absence of a functional flagella export apparatus, we showed that FliC could be secreted by the LEE-encoded T3SS and stimulate (Toll-like receptor 5) TLR5 signalling but could not confer motility. Since the secretion of FliC during A/E lesion formation would presumably be disadvantageous for the pathogen, we propose that virulence associated T3SSs and flagella T3SSs have evolved through a system of chaperones and complex regulatory pathways to be functional at different times to ensure that FliC secretion does not occur during T3SS effector translocation.

  14. Riemerella anatipestifer Type IX Secretion System Is Required for Virulence and Gelatinase Secretion

    Directory of Open Access Journals (Sweden)

    Yunqing Guo

    2017-12-01

    Full Text Available Riemerella anatipestifer (RA, a major causative agent of septicemia anserum exsudativa in domesticated ducklings, has a protein secretion system known as the type IX secretion system (T9SS. It is unknown whether the T9SS contributes to the virulence of RA through secretion of factors associated with pathogenesis. To answer this question, we constructed an RA mutant deficient in sprT, which encodes a core protein of the T9SS. Deletion of sprT yielded cells that failed to digest gelatin, an effect that was rescued via complementation by a plasmid encoding wild-type sprT. Complement-mediated killing was significantly increased in the deletion mutant, suggesting that proteins secreted by the T9SS are necessary for complement evasion in RA. Liquid chromatography-tandem mass spectrometry analysis revealed that RAYM_01812 and RAYM_04099 proteins containing a subtilisin-like serine protease domain and exhibiting extracellular gelatinase activity were secreted by the T9SS. Animal experiments demonstrated that the virulence of mutant strain ΔsprT strain was attenuated by 42,000-fold relative to wild-type RA-YM. Immunization with the ΔsprT protected ducks from challenge with RA-YM, suggesting that the former can be used as a live attenuated vaccine. These results indicate that the T9SS is functional in RA and contributes to its virulence by exporting key proteins. In addition, subtilisin-like serine proteases which are important virulence factors that interact with complement proteins may enable RA to evade immune surveillance in the avian innate immune system.

  15. IscR Is Essential for Yersinia pseudotuberculosis Type III Secretion and Virulence

    OpenAIRE

    Miller, Halie K.; Kwuan, Laura; Schwiesow, Leah; Bernick, David L.; Mettert, Erin; Ramirez, Hector A.; Ragle, James M.; Chan, Patricia P.; Kiley, Patricia J.; Lowe, Todd M.; Auerbuch, Victoria

    2014-01-01

    Type III secretion systems (T3SS) are essential for virulence in dozens of pathogens, but are not required for growth outside the host. Therefore, the T3SS of many bacterial species are under tight regulatory control. To increase our understanding of the molecular mechanisms behind T3SS regulation, we performed a transposon screen to identify genes important for T3SS function in the food-borne pathogen Yersinia pseudotuberculosis. We identified two unique transposon insertions in YPTB2860, a ...

  16. Study on the Regulation of Antidiuretic Hormone Secretion in Normal Subjects

    OpenAIRE

    高田, 徹; 島本, 和明

    1987-01-01

    In order to investigate the regulation mechanism of the antidiuretic hormone (ADH) secretion, the following tests were performed in normal subjects; hypertonic saline infusion, water-loading, isotonic (0.9%) saline infusion, two hours ambulation, noradrenaline infusion, angiotensin II infusion, nicotine loading by smoking and insulin injection. Plasma ADH levels, blood pressure, heart rate, plasma osmolality and hematocrit values were determined in each procedures. By the hypertonic saline in...

  17. Comparative Analysis of Volatile Defensive Secretions of Three Species of Pyrrhocoridae (Insecta: Heteroptera by Gas Chromatography-Mass Spectrometric Method.

    Directory of Open Access Journals (Sweden)

    Jan Krajicek

    Full Text Available The true bugs (Hemiptera: Heteroptera have evolved a system of well-developed scent glands that produce diverse and frequently strongly odorous compounds that act mainly as chemical protection against predators. A new method of non-lethal sampling with subsequent separation using gas chromatography with mass spectrometric detection was proposed for analysis of these volatile defensive secretions. Separation was performed on Rtx-200 column containing fluorinated polysiloxane stationary phase. Various mechanical irritation methods (ultrasonics, shaking, pressing bugs with plunger of syringe were tested for secretion sampling with a special focus on non-lethal irritation. The preconcentration step was performed by sorption on solid phase microextraction (SPME fibers with different polarity. For optimization of sampling procedure, Pyrrhocoris apterus was selected. The entire multi-parameter optimization procedure of secretion sampling was performed using response surface methodology. The irritation of bugs by pressing them with a plunger of syringe was shown to be the most suitable. The developed method was applied to analysis of secretions produced by adult males and females of Pyrrhocoris apterus, Pyrrhocoris tibialis and Scantius aegyptius (all Heteroptera: Pyrrhocoridae. The chemical composition of secretion, particularly that of alcohols, aldehydes and esters, is species-specific in all three pyrrhocorid species studied. The sexual dimorphism in occurrence of particular compounds is largely limited to alcohols and suggests their epigamic intraspecific function. The phenetic overall similarities in composition of secretion do not reflect either relationship of species or similarities in antipredatory color pattern. The similarities of secretions may be linked with antipredatory strategies. The proposed method requires only a few individuals which remain alive after the procedure. Thus secretions of a number of species including even the rare

  18. Secure Direct Communication Based on Secret Transmitting Order of Particles

    OpenAIRE

    Zhu, Ai-Dong; Xia, Yan; Fan, Qiu-Bo; Zhang, Shou

    2006-01-01

    We propose the schemes of quantum secure direct communication (QSDC) based on secret transmitting order of particles. In these protocols, the secret transmitting order of particles ensures the security of communication, and no secret messages are leaked even if the communication is interrupted for security. This strategy of security for communication is also generalized to quantum dialogue. It not only ensures the unconditional security but also improves the efficiency of communication.

  19. A Modular Toolkit for Generating Pichia pastoris Secretion Libraries.

    Science.gov (United States)

    Obst, Ulrike; Lu, Timothy K; Sieber, Volker

    2017-06-16

    Yeasts are powerful eukaryotic hosts for the production of recombinant proteins due to their rapid growth to high cell densities and ease of genetic modification. For large-scale industrial production, secretion of a protein offers the advantage of simple and efficient downstream purification that avoids costly cell rupture, denaturation and refolding. The methylotrophic yeast Pichia pastoris (Komagataella phaffi) is a well-established expression host that has the ability to perform post-translational modifications and is generally regarded as safe (GRAS). Nevertheless, optimization of protein secretion in this host remains a challenge due to the multiple steps involved during secretion and a lack of genetic tools to tune this process. Here, we developed a toolkit of standardized regulatory elements specific for Pichia pastoris allowing the tuning of gene expression and choice of protein secretion tag. As protein secretion is a complex process, these parts are compatible with a hierarchical assembly method to enable the generation of large and diverse secretion libraries in order to explore a wide range of secretion constructs, achieve successful secretion, and better understand the regulatory factors of importance to specific proteins of interest. To assess the performance of these parts, we built and characterized the expression and secretion efficiency of 124 constructs that combined different regulatory elements with two fluorescent reporter proteins (RFP, yEGFP). Intracellular expression from our promoters was comparatively independent of whether RFP or yEGFP, and whether plasmid-based expression or genomically integrated expression, was used. In contrast, secretion efficiency significantly varied for different genes expressed using identical regulatory elements, with differences in secretion efficiency of >10-fold observed. These results highlight the importance of generating diverse secretion libraries when searching for optimal expression conditions, and

  20. Secure direct communication based on secret transmitting order of particles

    International Nuclear Information System (INIS)

    Zhu Aidong; Zhang Shou; Xia Yan; Fan Qiubo

    2006-01-01

    We propose the schemes of quantum secure direct communication based on a secret transmitting order of particles. In these protocols, the secret transmitting order of particles ensures the security of communication, and no secret messages are leaked even if the communication is interrupted for security. This strategy of security for communication is also generalized to a quantum dialogue. It not only ensures the unconditional security but also improves the efficiency of communication