- Email: [email protected]
P28 Changes in plasma hydrogen sulfide and the significance in the diagnosis of Kawasaki disease
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Abstracts / Nitric Oxide 27 (2012) S11–S42
P26 Modulation of hydrogen sulfide and nitric oxide on tension of isolated human greater omentum artery Ming Wu a, Hao Liu b a The First Affiliated Hospital, Medical School of Xi’an Jiaotong University, Xian, Shanxi 710061, China b The First Affiliated Hospital, Medical School of Xi’an Jiaotong University, Department of Pharmacology, Xian, Shanxi 710061, China Background: Hydrogen Sulfide has been considered the third gaseous transmitter after nitric oxide and carbon monoxide. Increasing evidence indicates that hydrogen Sulfide has protective effect on cardiac and hepatic I/R injury or protective effect on remote organs of limbs I/R injury in rats. In this study, we investigate the modulation of hydrogen sulfide and nitric oxide on tension of isolated human greater omentum artery. Methods: The specimens of small arteries within greater omentum were harvested from 15 patients suffering from gastric cancer or colon-rectal cancer without local or distal transmission during open radical operation. The arteries were cut into about 2 mm artery rings. The dose–response curves of hydrogen sulfide donor NaHS (10 2, 10 3, 10 4, 10 5, 10 6 mol/L) and nitric oxide donor sodium nitroprusside (10 5, 10 6, 10 7, 10 8 mol/L) to artery rings were recorded with Powerlab and DMT system. Glibenclamide (10 4 mol/L), nitrendipine (10 4 mol/L) and Nx-nitro-L-arginine methyl ester (L-NAME) (10 4 mol/L) were used to study on the relaxation effect of NaHS (10 3 mol/L). Results: NaHS and sodium nitroprusside had a dose-dependent relaxation on isolated human greater omentum artery. Glibenclamide and Nx-nitro-L-arginine methyl ester (L-NAME) could make an inhibition of relaxation effect induced by NaHS, whereas nitrendipine could make a slightly enhancement. Interestingly, NaHS (10 3 M) could make a brief contraction to achieve maximal relaxation followed by another contraction. Conclusion: Hydrogen sulfide and nitric oxide could make an independent and collaborative relaxation on human greater omentum artery, but hydrogen sulfide at a specific concentration can cause a short contraction on the artery.
were further evaluated using several HbI mutants and X-ray absorption techniques (XAS). The dynamics of H2Swithin the HbI heme pocket were also evaluated by time-resolved absorption spectroscopy in the picosecond–nanosecond time range. XAS data shows that upon H2S binding to the HbI samples their absorption edges were red shifted by 1 eV with respect to the unliganded counterparts, indicating an increase of electron density on the ferric iron. Overall, the results suggest the formation of an ‘‘FeII–H2S’’ like derivative that coexists with the FeIII–H2S complex, upon H2S binding to rHbI and the HbI mutants. For HbI-H2S and the GlnE7His-H2S mutant, an Hbonding with the bound ligand can further modulate the FeII–H2S moiety of the intermediate (i.e. FeII–SH ), which can in principle facilitate interaction with a second H2S molecule, stimulating formation of the final deoxy and H2S2 species. Photo-excitation of the HbI FeIII–H2S complex resulted in photo-dissociation of the H2S from the ferric HbI, followed by fast H2S geminate rebinding with time constant sgem = 12 ± 1 ps. The fast rebinding reflects the high affinity of ferric HbI for H2S and supports the notion release of H2S is facilitated by another H2S molecule, which promotes heme reduction and polysulfide fromation. Since only one geminate rebinding is observed, we infer that there is no docking site for H2S within the heme and that only one energy barrier exists between solvent and heme pocket for sulfide binding. Thus, the rate-limmiting step for H2S releaseform ferric HbI is the diffusion of an aditional sulfide from the solvent to the heme pocket, which occurs at longer times scales. The fact that sulfide release in controlled by the rate of H2S diffusion from the solution to the vicinity of the heme, strongly suggest that hemeproteins modulate the concentration of free sulfide in the external environment, mediating in turn H2S signaling in cells. Disclosure: Nothing to disclose. References [1] R. Pietri, A. Lewis, R. G Leon, G. Casabona, L. Kiger, S. Yeh, S. Fernandez-Alberti, M.C. Marden, C.L. Cadilla, J. Lopez-Garriga, Factor controlling the reactivity of hydrogen sulfide with hemeproteins, Biochemistry 48 (2009) 4881–4894. [2] R. Pietri, E. Roman-Morales, J. Lopez-Garriga, Hydrogen sulfide snd hemeproteins: knowledge and mysteries, Antioxid Redox Signal 15 (2011) 393–404.
Disclosure: Nothing to disclose. http://dx.doi.org/10.1016/j.niox.2012.08.028 http://dx.doi.org/10.1016/j.niox.2012.08.027
P28 P27 Interaction of H2S with hemeproteins modulates the concentration of free sulfide compounds in solution and mediates H2S signaling Ruth Pietri a, Cacimar Ramos-Alvarez a, Juan Lopez-Garriga a, Professor Michel Negrerie b a University of Puerto Rico-Mayaguez, Chemistry, Mayaguez 00680, Puerto Rico b Ecole Polytechnique, Laboratoire d’Optique et Biosciences, Palaiseau 91128, France Metalloproteins, particularly hemeproteins have the potential to mediate H2S signaling in cells. In fact, using the hemoglobin I (HbI) from the clam L. pectinata as a model we have previously suggested that H2S binds tightly to the ferric iron of hemeproteins and that its release is controlled by two competing reactions involving simple sulfide dissociation and heme reduction [1,2]. At high H2S concentrations, reduction of the heme iron is stimulated by a second H2S molecule with the concomitant formation of ferrous heme and free polysulfides. To define the molecular details implicated in the electron transfer process and the role of distal residues in this process, the structural aspects associated with the heme-H2S moiety
Changes in plasma hydrogen sulfide and the significance in the diagnosis of Kawasaki disease Hui Yan a, Yue Yuan b, Hong Wan a, Yan Sun a, Xueying Li a, Chaoshu Tang a, Junbao Du a, Ping Leung c, Hongfang Jin a a Peking University First Hospital, Beijing 100034, China b Beijing Children’s Hospital, Beijing 100045, China c Premier Medical Center, Hong Kong, China Objective: Kawasaki disease (KD) is an acute systemic inflammatory disease in childhood. Our aim was to find out a possible biomarker which might represent the development of KD and the following coronary artery lesions. Study design: A prospective unmatched case-control study was designed. Forty-eight KD patients, 57 non-KD fever patients and 27 non-fever children were recruited for the research. KD patients were further divided into subgroups according to coronary artery abnormalities. Plasma hydrogen sulfide (H2S) was examined by sulfidesensitive electrode method. Results: Plasma H2S levels in KD patients during acute period were significantly lower than those during convalescent period (34.37 ± 8.11 vs 38.17 ± 8.63, p < 0.05). Plasma H2S levels in KD patients during acute period were significantly lower than those in
Abstracts / Nitric Oxide 27 (2012) S11–S42
non-KD fever patients (34.37 ± 8.11 vs 55.77 ± 17.88, p < 0.05). There was a negative correlation between the plasma level of H2S and C-reactive protein, and between the plasma level of H2S and erythrocyte sedimentation rate in all participants, respectively (r = 0.511 and 0.481, respectively; p < 0.05). Receiver operating characteristic (ROC) curve analysis revealed a diagnosis of KD (ROC area: 0.905 ± 0.028, p < 0.001, 95% confidence interval: 0.849–0.960, optimal cutoff value: 44.705 lmol/L) and a prediction of coronary artery injury (ROC area: 0.834 ± 0.045, p < 0.001, 95% confidence interval: 0.745–0.922, optimal cutoff value: 43.78 lmol/L). Conclusions: Plasma H2S level in acute period might be a potentially useful biomarker for assisting the diagnosis of KD and predicting coronary lesions. Disclosure: Nothing to disclose. http://dx.doi.org/10.1016/j.niox.2012.08.029
P29 Children suffering from postural orthostatic tachycardia syndrome with a marked increase in erythrocytic hydrogen sulfide have a better therapeutic response to midodrine hydrochloride Jinyan Yang a, Juan Zhao a, Die Liu a, Chunhin Fu d, Xueying Li a, Stella Chen b, Fengwen Zhang a, Chaoshu Tang c, Junbao Du a, Hongfang Jin a a Peking University First Hospital, Beijing 100034, China b University of California, San Diego, CA 92093, United States c Peking University Health Sciences Centre, Beijing 100191, China d Hong Kong University of Science and Technology, Hong Kong, China Background: Midodrine hydrochloride is an important therapeutic option for children with postural orthostatic tachycardia syndrome (POTS). However, there are few methods to predict response to the drug. Endogenous hydrogen sulfide plays an important role in the pathogenesis of POTS. The present study was to explore the predictive value of erythrocytic hydrogen sulfide in predicting the therapeutic efficacy of midodrine hydrochloride for children with POTS. Methods: Sixty-eight children were included in the study, of whom 28 children suffered from POTS (POTS group) and 40 healthy children served as control group. Children in POTS group received midodrine hydrochloride treatment. The erythrocyte hydrogen sulfide production was measured by sensitive sulphur electrode and a receiver operating characteristic (ROC) curve was used to test if erythrocyte hydrogen sulfide could predict the therapeutic response to midodrine hydrochloride for children with POTS. Results: Hydrogen sulfide production from erythrocyte was significantly higher in children with POTS than control subjects (p < 0.001). Erythrocyte hydrogen sulfide production in responders to midodrine hydrochloride was significantly higher than that in non-responders (p < 0.05). ROC curve revealed that the area under curve was 0.857 with a 95% confidence interval (CI) of 0.715–0.999. Erythrocytic hydrogen sulfide production yielded both high sensitivity (81.0%) and specificity (85.7%) in predicting the efficacy of midodrine hydrochloride therapy for POTS in children. Conclusion: Erythrocytic hydrogen sulfide could serve as a useful predictor of therapeutic response to midodrine hydrochloride in POTS of children. Disclosure: Nothing to disclose. http://dx.doi.org/10.1016/j.niox.2012.08.030
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P30 Effect of exogenous hydrogen sulfide on Phaeodactylum tricornutum growth and eicosapentaenoic acid accumulation Yang cang Xu a, Tao Yu b, Xiaoyan Wang b, Yunshan Zhong b, Wenzong Xu b a Tianjin Key Laboratory of Marine Resources and Chemistry, Tianjin Economic Development Area, Tianjin 300457, China b College of Marine Science and Engineering, Tianjin University of Science & Technology, Tianjin Economic Development Area, Tianjin 300457, China Background: Hydrogen sulfide ( H2S) is now considered the third gaseous signal molecule along with nitric oxide and carbon monoxide. It has been shown that at appropriate concentrations it plays important physiological functions. The marine diatom Phaeodactylum tricornutum is a potential source of the pharmaceutically valuable x-3 polyunsaturated fatty acid eicosapentaenoic acid (EPA). This paper studied the effect of exogenous H2S on P. tricornutum growth rate and EPA content. Materials and methods: The P. tricornutum were grown in f/2 medium with or without sodium hydrosulfide at 25 °C and illuminated with cool-white fluorescent light at a level of 60 lmol/m s (12L:12D). The cultures were routinely shaken (2–3 times per day) and while at exponential growth the cells were harvested at the end of dark period and used for the experimentations. The growth rate was determined by cell number variation. The EPA was extracted by chloroform–methanol (2:1) and the content was determined by gas chromatography (GC-17A). Results: The cell number variation of P. tricornutum cultured in the medium contained respectively 0.0 mmol/L, 0.3 mmol/L, 0.6 mmol/L, 0.9 mmol/L and 1.2 mmol/L sodium hydrosulfide were 6.2 105 cells/mL, 6.1 105 cells/mL, 9.6 105 cells/mL, 4.9 105 cells/ mL and 2.8 105 cells/mL. It indicated that exogenous H2S had no significant impact on P. tricornutum growth at low concentration (0.3 mmol/L). And it inhibited P. tricornutum growth at high concentration (above 0.9 mmol/L). And it promoted P. tricornutum growth at 0.6 mmol/L concentration. Under the same culture condition, the EPA content variation were 384 mg/g dry weight, 402 mg/g dry weight, 399 mg/g dry weight, 498 mg/g dry weight and 524 mg/g dry weight. It was clear that high concentration H2S promoted EPA accumulation and low concentration H2S had no significant effect on EPA accumulation. Conclusion: Both growth and EPA accumulation in P. tricornutum were effected by gaseous signal molecule H2S. And the role of H2S on them depended on its concentration. High concentration H2S inhibited P. tricornutum growth but promoted EPA accumulation. Disclosure: The Project Supported by the Foundation (No. 201102) of Tianjin Key Laboratory of Marine Resources and Chemistry (Tianjin University of Science & Technology), PR China. http://dx.doi.org/10.1016/j.niox.2012.08.031
P31 Sulfide metabolism at low oxygen conditions Jose Matallo a, Josef Vogt a, Michael Georgieff a, Csaba Szabó b, Peter Radermacher a, Enrico Calzia a a Ulm University, Anesthesiology, Ulm 89075, Germany b University of Texas Medical Branch, Anesthesiology, Galveston, TX 77555, United States Background: Even in higher species sulfide is quickly metabolised and thus degraded by an ancient metabolic pathway linked to the mitochondrial respiratory chain [1]. Since this metabolic process is strictly aerobic, sulfide concentration is expected to increase at low oxygen, provided that the production rate remains constant.
Abstracts / Nitric Oxide 27 (2012) S11–S42
P26 Modulation of hydrogen sulfide and nitric oxide on tension of isolated human greater omentum artery Ming Wu a, Hao Liu b a The First Affiliated Hospital, Medical School of Xi’an Jiaotong University, Xian, Shanxi 710061, China b The First Affiliated Hospital, Medical School of Xi’an Jiaotong University, Department of Pharmacology, Xian, Shanxi 710061, China Background: Hydrogen Sulfide has been considered the third gaseous transmitter after nitric oxide and carbon monoxide. Increasing evidence indicates that hydrogen Sulfide has protective effect on cardiac and hepatic I/R injury or protective effect on remote organs of limbs I/R injury in rats. In this study, we investigate the modulation of hydrogen sulfide and nitric oxide on tension of isolated human greater omentum artery. Methods: The specimens of small arteries within greater omentum were harvested from 15 patients suffering from gastric cancer or colon-rectal cancer without local or distal transmission during open radical operation. The arteries were cut into about 2 mm artery rings. The dose–response curves of hydrogen sulfide donor NaHS (10 2, 10 3, 10 4, 10 5, 10 6 mol/L) and nitric oxide donor sodium nitroprusside (10 5, 10 6, 10 7, 10 8 mol/L) to artery rings were recorded with Powerlab and DMT system. Glibenclamide (10 4 mol/L), nitrendipine (10 4 mol/L) and Nx-nitro-L-arginine methyl ester (L-NAME) (10 4 mol/L) were used to study on the relaxation effect of NaHS (10 3 mol/L). Results: NaHS and sodium nitroprusside had a dose-dependent relaxation on isolated human greater omentum artery. Glibenclamide and Nx-nitro-L-arginine methyl ester (L-NAME) could make an inhibition of relaxation effect induced by NaHS, whereas nitrendipine could make a slightly enhancement. Interestingly, NaHS (10 3 M) could make a brief contraction to achieve maximal relaxation followed by another contraction. Conclusion: Hydrogen sulfide and nitric oxide could make an independent and collaborative relaxation on human greater omentum artery, but hydrogen sulfide at a specific concentration can cause a short contraction on the artery.
were further evaluated using several HbI mutants and X-ray absorption techniques (XAS). The dynamics of H2Swithin the HbI heme pocket were also evaluated by time-resolved absorption spectroscopy in the picosecond–nanosecond time range. XAS data shows that upon H2S binding to the HbI samples their absorption edges were red shifted by 1 eV with respect to the unliganded counterparts, indicating an increase of electron density on the ferric iron. Overall, the results suggest the formation of an ‘‘FeII–H2S’’ like derivative that coexists with the FeIII–H2S complex, upon H2S binding to rHbI and the HbI mutants. For HbI-H2S and the GlnE7His-H2S mutant, an Hbonding with the bound ligand can further modulate the FeII–H2S moiety of the intermediate (i.e. FeII–SH ), which can in principle facilitate interaction with a second H2S molecule, stimulating formation of the final deoxy and H2S2 species. Photo-excitation of the HbI FeIII–H2S complex resulted in photo-dissociation of the H2S from the ferric HbI, followed by fast H2S geminate rebinding with time constant sgem = 12 ± 1 ps. The fast rebinding reflects the high affinity of ferric HbI for H2S and supports the notion release of H2S is facilitated by another H2S molecule, which promotes heme reduction and polysulfide fromation. Since only one geminate rebinding is observed, we infer that there is no docking site for H2S within the heme and that only one energy barrier exists between solvent and heme pocket for sulfide binding. Thus, the rate-limmiting step for H2S releaseform ferric HbI is the diffusion of an aditional sulfide from the solvent to the heme pocket, which occurs at longer times scales. The fact that sulfide release in controlled by the rate of H2S diffusion from the solution to the vicinity of the heme, strongly suggest that hemeproteins modulate the concentration of free sulfide in the external environment, mediating in turn H2S signaling in cells. Disclosure: Nothing to disclose. References [1] R. Pietri, A. Lewis, R. G Leon, G. Casabona, L. Kiger, S. Yeh, S. Fernandez-Alberti, M.C. Marden, C.L. Cadilla, J. Lopez-Garriga, Factor controlling the reactivity of hydrogen sulfide with hemeproteins, Biochemistry 48 (2009) 4881–4894. [2] R. Pietri, E. Roman-Morales, J. Lopez-Garriga, Hydrogen sulfide snd hemeproteins: knowledge and mysteries, Antioxid Redox Signal 15 (2011) 393–404.
Disclosure: Nothing to disclose. http://dx.doi.org/10.1016/j.niox.2012.08.028 http://dx.doi.org/10.1016/j.niox.2012.08.027
P28 P27 Interaction of H2S with hemeproteins modulates the concentration of free sulfide compounds in solution and mediates H2S signaling Ruth Pietri a, Cacimar Ramos-Alvarez a, Juan Lopez-Garriga a, Professor Michel Negrerie b a University of Puerto Rico-Mayaguez, Chemistry, Mayaguez 00680, Puerto Rico b Ecole Polytechnique, Laboratoire d’Optique et Biosciences, Palaiseau 91128, France Metalloproteins, particularly hemeproteins have the potential to mediate H2S signaling in cells. In fact, using the hemoglobin I (HbI) from the clam L. pectinata as a model we have previously suggested that H2S binds tightly to the ferric iron of hemeproteins and that its release is controlled by two competing reactions involving simple sulfide dissociation and heme reduction [1,2]. At high H2S concentrations, reduction of the heme iron is stimulated by a second H2S molecule with the concomitant formation of ferrous heme and free polysulfides. To define the molecular details implicated in the electron transfer process and the role of distal residues in this process, the structural aspects associated with the heme-H2S moiety
Changes in plasma hydrogen sulfide and the significance in the diagnosis of Kawasaki disease Hui Yan a, Yue Yuan b, Hong Wan a, Yan Sun a, Xueying Li a, Chaoshu Tang a, Junbao Du a, Ping Leung c, Hongfang Jin a a Peking University First Hospital, Beijing 100034, China b Beijing Children’s Hospital, Beijing 100045, China c Premier Medical Center, Hong Kong, China Objective: Kawasaki disease (KD) is an acute systemic inflammatory disease in childhood. Our aim was to find out a possible biomarker which might represent the development of KD and the following coronary artery lesions. Study design: A prospective unmatched case-control study was designed. Forty-eight KD patients, 57 non-KD fever patients and 27 non-fever children were recruited for the research. KD patients were further divided into subgroups according to coronary artery abnormalities. Plasma hydrogen sulfide (H2S) was examined by sulfidesensitive electrode method. Results: Plasma H2S levels in KD patients during acute period were significantly lower than those during convalescent period (34.37 ± 8.11 vs 38.17 ± 8.63, p < 0.05). Plasma H2S levels in KD patients during acute period were significantly lower than those in
Abstracts / Nitric Oxide 27 (2012) S11–S42
non-KD fever patients (34.37 ± 8.11 vs 55.77 ± 17.88, p < 0.05). There was a negative correlation between the plasma level of H2S and C-reactive protein, and between the plasma level of H2S and erythrocyte sedimentation rate in all participants, respectively (r = 0.511 and 0.481, respectively; p < 0.05). Receiver operating characteristic (ROC) curve analysis revealed a diagnosis of KD (ROC area: 0.905 ± 0.028, p < 0.001, 95% confidence interval: 0.849–0.960, optimal cutoff value: 44.705 lmol/L) and a prediction of coronary artery injury (ROC area: 0.834 ± 0.045, p < 0.001, 95% confidence interval: 0.745–0.922, optimal cutoff value: 43.78 lmol/L). Conclusions: Plasma H2S level in acute period might be a potentially useful biomarker for assisting the diagnosis of KD and predicting coronary lesions. Disclosure: Nothing to disclose. http://dx.doi.org/10.1016/j.niox.2012.08.029
P29 Children suffering from postural orthostatic tachycardia syndrome with a marked increase in erythrocytic hydrogen sulfide have a better therapeutic response to midodrine hydrochloride Jinyan Yang a, Juan Zhao a, Die Liu a, Chunhin Fu d, Xueying Li a, Stella Chen b, Fengwen Zhang a, Chaoshu Tang c, Junbao Du a, Hongfang Jin a a Peking University First Hospital, Beijing 100034, China b University of California, San Diego, CA 92093, United States c Peking University Health Sciences Centre, Beijing 100191, China d Hong Kong University of Science and Technology, Hong Kong, China Background: Midodrine hydrochloride is an important therapeutic option for children with postural orthostatic tachycardia syndrome (POTS). However, there are few methods to predict response to the drug. Endogenous hydrogen sulfide plays an important role in the pathogenesis of POTS. The present study was to explore the predictive value of erythrocytic hydrogen sulfide in predicting the therapeutic efficacy of midodrine hydrochloride for children with POTS. Methods: Sixty-eight children were included in the study, of whom 28 children suffered from POTS (POTS group) and 40 healthy children served as control group. Children in POTS group received midodrine hydrochloride treatment. The erythrocyte hydrogen sulfide production was measured by sensitive sulphur electrode and a receiver operating characteristic (ROC) curve was used to test if erythrocyte hydrogen sulfide could predict the therapeutic response to midodrine hydrochloride for children with POTS. Results: Hydrogen sulfide production from erythrocyte was significantly higher in children with POTS than control subjects (p < 0.001). Erythrocyte hydrogen sulfide production in responders to midodrine hydrochloride was significantly higher than that in non-responders (p < 0.05). ROC curve revealed that the area under curve was 0.857 with a 95% confidence interval (CI) of 0.715–0.999. Erythrocytic hydrogen sulfide production yielded both high sensitivity (81.0%) and specificity (85.7%) in predicting the efficacy of midodrine hydrochloride therapy for POTS in children. Conclusion: Erythrocytic hydrogen sulfide could serve as a useful predictor of therapeutic response to midodrine hydrochloride in POTS of children. Disclosure: Nothing to disclose. http://dx.doi.org/10.1016/j.niox.2012.08.030
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P30 Effect of exogenous hydrogen sulfide on Phaeodactylum tricornutum growth and eicosapentaenoic acid accumulation Yang cang Xu a, Tao Yu b, Xiaoyan Wang b, Yunshan Zhong b, Wenzong Xu b a Tianjin Key Laboratory of Marine Resources and Chemistry, Tianjin Economic Development Area, Tianjin 300457, China b College of Marine Science and Engineering, Tianjin University of Science & Technology, Tianjin Economic Development Area, Tianjin 300457, China Background: Hydrogen sulfide ( H2S) is now considered the third gaseous signal molecule along with nitric oxide and carbon monoxide. It has been shown that at appropriate concentrations it plays important physiological functions. The marine diatom Phaeodactylum tricornutum is a potential source of the pharmaceutically valuable x-3 polyunsaturated fatty acid eicosapentaenoic acid (EPA). This paper studied the effect of exogenous H2S on P. tricornutum growth rate and EPA content. Materials and methods: The P. tricornutum were grown in f/2 medium with or without sodium hydrosulfide at 25 °C and illuminated with cool-white fluorescent light at a level of 60 lmol/m s (12L:12D). The cultures were routinely shaken (2–3 times per day) and while at exponential growth the cells were harvested at the end of dark period and used for the experimentations. The growth rate was determined by cell number variation. The EPA was extracted by chloroform–methanol (2:1) and the content was determined by gas chromatography (GC-17A). Results: The cell number variation of P. tricornutum cultured in the medium contained respectively 0.0 mmol/L, 0.3 mmol/L, 0.6 mmol/L, 0.9 mmol/L and 1.2 mmol/L sodium hydrosulfide were 6.2 105 cells/mL, 6.1 105 cells/mL, 9.6 105 cells/mL, 4.9 105 cells/ mL and 2.8 105 cells/mL. It indicated that exogenous H2S had no significant impact on P. tricornutum growth at low concentration (0.3 mmol/L). And it inhibited P. tricornutum growth at high concentration (above 0.9 mmol/L). And it promoted P. tricornutum growth at 0.6 mmol/L concentration. Under the same culture condition, the EPA content variation were 384 mg/g dry weight, 402 mg/g dry weight, 399 mg/g dry weight, 498 mg/g dry weight and 524 mg/g dry weight. It was clear that high concentration H2S promoted EPA accumulation and low concentration H2S had no significant effect on EPA accumulation. Conclusion: Both growth and EPA accumulation in P. tricornutum were effected by gaseous signal molecule H2S. And the role of H2S on them depended on its concentration. High concentration H2S inhibited P. tricornutum growth but promoted EPA accumulation. Disclosure: The Project Supported by the Foundation (No. 201102) of Tianjin Key Laboratory of Marine Resources and Chemistry (Tianjin University of Science & Technology), PR China. http://dx.doi.org/10.1016/j.niox.2012.08.031
P31 Sulfide metabolism at low oxygen conditions Jose Matallo a, Josef Vogt a, Michael Georgieff a, Csaba Szabó b, Peter Radermacher a, Enrico Calzia a a Ulm University, Anesthesiology, Ulm 89075, Germany b University of Texas Medical Branch, Anesthesiology, Galveston, TX 77555, United States Background: Even in higher species sulfide is quickly metabolised and thus degraded by an ancient metabolic pathway linked to the mitochondrial respiratory chain [1]. Since this metabolic process is strictly aerobic, sulfide concentration is expected to increase at low oxygen, provided that the production rate remains constant.