共查询到20条相似文献,搜索用时 15 毫秒
1.
Yan Li Heng Yin Qing Wang Xiaoming Zhao Yuguang Du Fenglan Li 《Carbohydrate polymers》2009,75(4):612-617
NO (nitric oxide) and H2O2 (hydrogen peroxide) are important signaling molecule in plants. Brassica napus L. was used to understand oligochitosan inducing production of NO (nitric oxide) and H2O2 (hydrogen peroxide) and their physiological function. The result showed that the production of NO and H2O2 in epidermal cells of B. napus L. was induced with oligochitosan by fluorescence microscope. And it was proved that there was an interaction between NO and H2O2 with L-NAME (NG-nitro-l-arg-methyl eater), which is an inhibitor of NOS (NO synthase) in mammalian cells that also inhibits plant NO synthesis, and CAT (catalase), which is an important H2O2 scavenger, respectively. It was found that NO and H2O2 induced by oligochitosan took part in inducing reduction in stomatal aperture and LEA protein gene expression of leaves of B. napus L. All these results showed that oligochitosan have potential activities of improving resistance to water stress. 相似文献
2.
3.
Gas production by Chlamydomonas moewusii in the light has been followed by manometric techniques during the adaptation to anaerobiosis. The only detectable gases produced are CO2 and H2 CO2 is produced at a rather constant rate whereas H2 evolution increase with time. This increase of H2 evolution during the adaptation period can be inhibited by cycloheximide and by chloral hydrate, two inhibitors of protein synthesis. If the inhibitors are added to already adapted cells there is no effect on H2 evolution. Adapted cell suspensions are sensitive to oxygen. Incubation under O2 for 10 min inhibits the H2 evolution to 100%. After removal of oxygen the capability to evolve H2 can be restored only by a new adaptation period. This second adaptation to H2 evolution can also be inhibited by cycloheximide. 相似文献
4.
Heat shock (HS, 40°C, 10 min) induces hypericin production, nitric oxide (NO) generation, and hydrogen peroxide (H2O2) accumulation of Hypericum perforatum suspension cells. Catalase (CAT) and NO specific scavenger 2–4-carboxyphenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide
(cPTIO) suppress not only the HS-induced H2O2 generation and NO burst, but also the HS-triggered hypericin production. Hypericin contents of the cells treated with both
NO and H2O2 are significantly higher than those of the cells treated with NO alone, although H2O2 per se has no effects on hypericin production of the cells, which suggests the synergistic action between H2O2 and NO on hypericin production. NO treatment enhances H2O2 levels of H. perforatum cells, while external application of H2O2 induces NO generation of cells. Thus, the results reveal a mutually amplifying action between H2O2 and NO in H. perforatum cells. CAT treatment inhibits both HS-induced H2O2 accumulation and NO generation, while cPTIO can also suppress H2O2 levels of the heat shocked cells. The results imply that H2O2 and NO may enhance each other’s levels by their mutually amplifying action in the heat shocked cells. Membrane NAD(P)H oxidase
inhibitor diphenylene iodonium (DPI) and nitric oxide synthase (NOS) inhibitor S,S′-1,3-phenylene-bis(1,2-ethanediyl)-bis-isothiourea
(PBITU) not only inhibit the mutually amplifying action between H2O2 and NO but also abolish the synergistic effects of H2O2 and NO on hypericin production, showing that the synergism of H2O2 and NO on secondary metabolite biosynthesis might be dependent on their mutual amplification. Taken together, data of the
present work demonstrate that both H2O2 and NO are essential for HS-induced hypericin production of H. perforatum suspension cells. Furthermore, the results reveal a special interaction between the two signal molecules in mediating HS-triggered
secondary metabolite biosynthesis of the cells. 相似文献
5.
Ascorbate accumulation during sulphur deprivation and its effects on photosystem II activity and H2 production of the green alga Chlamydomonas reinhardtii
下载免费PDF全文
![点击此处可从《Plant, cell & environment》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Valéria Nagy André Vidal‐Meireles Roland Tengölics Gábor Rákhely Győző Garab László Kovács Szilvia Z. Tóth 《Plant, cell & environment》2016,39(7):1460-1472
In nature, H2 production in Chlamydomonas reinhardtii serves as a safety valve during the induction of photosynthesis in anoxia, and it prevents the over‐reduction of the photosynthetic electron transport chain. Sulphur deprivation of C. reinhardtii also triggers a complex metabolic response resulting in the induction of various stress‐related genes, down‐regulation of photosynthesis, the establishment of anaerobiosis and expression of active hydrogenase. Photosystem II (PSII) plays dual role in H2 production because it supplies electrons but the evolved O2 inhibits the hydrogenase. Here, we show that upon sulphur deprivation, the ascorbate content in C. reinhardtii increases about 50‐fold, reaching the mM range; at this concentration, ascorbate inactivates the Mn‐cluster of PSII, and afterwards, it can donate electrons to tyrozin Z+ at a slow rate. This stage is followed by donor‐side‐induced photoinhibition, leading to the loss of charge separation activity in PSII and reaction centre degradation. The time point at which maximum ascorbate concentration is reached in the cell is critical for the establishment of anaerobiosis and initiation of H2 production. We also show that ascorbate influenced H2 evolution via altering the photosynthetic electron transport rather than hydrogenase activity and starch degradation. 相似文献
6.
Huan Chen Qiujun Lin Zhuo Li Jin Chu Hai Dong Qiong Mei Yuanhu Xuan 《Molecular Plant Pathology》2023,24(3):221-231
Sheath blight (ShB) severely threatens rice cultivation and production; however, the molecular mechanism of rice defence against ShB remains unclear. Screening of transposon Ds insertion mutants identified that Calcineurin B-like protein-interacting protein kinase 31 (CIPK31) mutants were more susceptible to ShB, while CIPK31 overexpressors (OX) were less susceptible. Sequence analysis indicated two haplotypes of CIPK31: Hap_1, with significantly higher CIPK31 expression, was less sensitive to ShB than the Hap_2 lines. Further analyses showed that the NAF domain of CIPK31 interacted with the EF-hand motif of respiratory burst oxidase homologue (RBOHA) to inhibit RBOHA-induced H2O2 production, and RBOHA RNAi plants were more susceptible to ShB. These data suggested that the CIPK31-mediated increase in resistance is not associated with RBOHA. Interestingly, the study also found that CIPK31 interacted with catalase C (CatC); cipk31 mutants accumulated less H2O2 while CIPK31 OX accumulated more H2O2 compared to the wild-type control. Further analysis showed the interaction of the catalase domain of CatC with the NAF domain of CIPK31 by which CIPK31 inhibits CatC activity to accumulate more H2O2. 相似文献
7.
High homocysteine levels prevent via H2S the CoCl2‐induced alteration of lymphocyte viability
下载免费PDF全文
![点击此处可从《Journal of cellular and molecular medicine》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Julien Fromonot Josée‐Martine Durand‐Gorde Jocelyne Condo Nathalie Kipson Giovanna Mottola Pierre Deharo Régis Guieu Jean Ruf 《Journal of cellular and molecular medicine》2016,20(8):1411-1419
High homocysteine (HCy) levels are associated with lymphocyte‐mediated inflammatory responses that are sometimes in turn related to hypoxia. Because adenosine is a potent lymphocyte suppressor produced in hypoxic conditions and shares metabolic pathways with HCy, we addressed the influence of high HCy levels on the hypoxia‐induced, adenosine‐mediated, alteration of lymphocyte viability. We treated mitogen‐stimulated human lymphocytes isolated from healthy individuals and the human lymphoma T‐cell line CEM with cobalt chloride (CoCl2)to reproduce hypoxia. We found that CoCl2‐altered cell viability was dose‐dependently reversed using HCy. In turn, the HCy effect was inhibited using DL‐propargylglycine, a specific inhibitor of the hydrogen sulphide (H2S)‐synthesizing enzyme cystathionine‐γ‐lyase involved in HCy catabolism. We then addressed the intracellular metabolic pathway of adenosine and HCy, and the role of the adenosine A2A receptor (A2AR). We observed that: (i) hypoxic conditions lowered the intracellular concentration of HCy by increasing adenosine production, which resulted in high A2AR expression and 3′, 5′‐cyclic adenosine monophosphate production; (ii) increasing intracellular HCy concentration reversed the hypoxia‐induced adenosinergic signalling despite high adenosine concentration by promoting both S‐adenosylhomocysteine and H2S production; (iii) DL‐propargylglycine that inhibits H2S production abolished the HCy effect. Together, these data suggest that high HCy levels prevent, via H2S production and the resulting down‐regulation of A2AR expression, the hypoxia‐induced adenosinergic alteration of lymphocyte viability. We point out the relevance of these mechanisms in the pathophysiology of cardiovascular diseases. 相似文献
8.
Armen Trchounian 《Critical reviews in biotechnology》2015,35(1):103-113
H2 has a great potential as an ecologically-clean, renewable and capable fuel. It can be mainly produced via hydrogenases (Hyd) by different bacteria, especially Escherichia coli and Rhodobacter sphaeroides. The operation direction and activity of multiple Hyd enzymes in E. coli during mixed-acid fermentation might determine H2 production; some metabolic cross-talk between Hyd enzymes is proposed. Manipulating the activity of different Hyd enzymes is an effective way to enhance H2 production by E. coli in biotechnology. Moreover, a novel approach would be the use of glycerol as feedstock in fermentation processes leading to H2 production. Mixed carbon (sugar and glycerol) utilization studies enlarge the kind of organic wastes used in biotechnology. During photo-fermentation under limited nitrogen conditions, H2 production by Rh. sphaeroides is observed when carbon and nitrogen sources are supplemented. The relationship of H2 production with H+ transport across the membrane and membrane-associated ATPase activity is shown. On the other hand, combination of carbon sources (succinate, malate) with different nitrogen sources (yeast extract, glutamate, glycine) as well as different metal (Fe, Ni, Mg) ions might regulate H2 production. All these can enhance H2 production yield by Rh. sphaeroides in biotechnology Finally, two of these bacteria might be combined to develop and consequently to optimize two stages of H2 production biotechnology with high efficiency transformation of different organic sources. 相似文献
9.
Hydrogen (H2) production by Thermococcus kodakarensis compares very favourably with the levels reported for the most productive algal, fungal and bacterial systems. T. kodakarensis can also consume H2 and is predicted to use several alternative pathways to recycle reduced cofactors, some of which may compete with H2 production for reductant disposal. To explore the reductant flux and possible competition for H2 production in vivo, T. kodakarensis TS517 was mutated to precisely delete each of the alternative pathways of reductant disposal, H2 production and consumption. The results obtained establish that H2 is generated predominantly by the membrane‐bound hydrogenase complex (Mbh), confirm the essential role of the SurR (TK1086p) regulator in vivo, delineate the roles of sulfur (S°) regulon proteins and demonstrate that preventing H2 consumption results in a substantial net increase in H2 production. Constitutive expression of TK1086 (surR) from a replicative plasmid restored the ability of T. kodakarensis TS1101 (ΔTK1086) to grow in the absence of S° and stimulated H2 production, revealing a second mechanism to increase H2 production. Transformation of T. kodakarensis TS1101 with plasmids that express SurR variants constructed to direct the constitutive synthesis of the Mbh complex and prevent expression of the S° regulon was only possible in the absence of S° and, under these conditions, the transformants exhibited wild‐type growth and H2 production. With S° present, they grew slower but synthesized more H2 per unit biomass than T. kodakarensis TS517. 相似文献
10.
The presence of 2 mM bicarbonate in the incubation medium induced stomatal closure in abaxial epidermis of Arabidopsis. Exposure to 2 mM bicarbonate elevated the levels of H2O2 in guard cells within 5 min, as indicated by the fluorescent probe, dichlorofluorescein diacetate (H2DCF-DA). Bicarbonate-induced stomatal closure as well as H2O2 production were restricted by exogenous catalase or diphenylene iodonium (DPI, an inhibitor of NAD(P)H oxidase). The reduced
sensitivity of stomata to bicarbonate and H2O2 production in homozygous atrbohD/F double mutant of Arabidopsis confirmed that NADP(H) oxidase is involved during bicarbonate induced ROS production in guard cells. The production of H2O2 was quicker and greater with ABA than that with bicarbonate. Such pattern of H2O2 production may be one of the reasons for ABA being more effective than bicarbonate, in promoting stomatal closure. Our results
demonstrate that H2O2 is an essential secondary messenger during bicarbonate induced stomatal closure in Arabidopsis. 相似文献
11.
Maojun Xu Jinxing Sheng Huizhong Wang Jufang Dong 《Plant Cell, Tissue and Organ Culture》2011,105(1):47-53
PB90 is a novel protein elicitor isolated from Phytophthora boehmeriae. Here, we report that treatment of PB90 stimulates hypericin production and hydrogen peroxide (H2O2) generation in Hypericum perforatum L. cells and demonstrate that H2O2 is essential for PB90-induced hypericin production. To further study the source of PB90-triggered H2O2, we have investigated activities of plasma membrane NADPH oxidase in Hypericum perforatum L. cells subjected to PB90 treatment. It is revealed that treatment of the cells with PB90 significantly increases NADPH
oxidase activity. NADPH oxidase inhibitors suppress not only the PB90-stimulated NADPH oxidase activity but also the PB90-triggered
H2O2 generation and PB90-induced hypericin production, showing that NADPH oxidase is involved in PB90-triggered H2O2 generation and hypericin production. Moreover, the suppression of NADPH oxidase inhibitors on PB90-induced hypericin production
can be reversed by H2O2, although H2O2
per se has no effects on hypericin production of the cells. Together, the data demonstrate that PB90 may induce hypericin production
of H. perforatum cells through the NADPH oxidase-mediated H2O2 signaling pathway. 相似文献
12.
Heterotrimeric G protein mediates ethylene‐induced stomatal closure via hydrogen peroxide synthesis in Arabidopsis
下载免费PDF全文
![点击此处可从《The Plant journal : for cell and molecular biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Xiao‐Min Ge Hong‐Li Cai Xue Lei Xue Zhou Ming Yue Jun‐Min He 《The Plant journal : for cell and molecular biology》2015,82(1):138-150
Heterotrimeric G proteins function as key players in hydrogen peroxide (H2O2) production in plant cells, but whether G proteins mediate ethylene‐induced H2O2 production and stomatal closure are not clear. Here, evidences are provided to show the Gα subunit GPA1 as a missing link between ethylene and H2O2 in guard cell ethylene signalling. In wild‐type leaves, ethylene‐triggered H2O2 synthesis and stomatal closure were dependent on activation of Gα. GPA1 mutants showed the defect of ethylene‐induced H2O2 production and stomatal closure, whereas wGα and cGα overexpression lines showed faster stomatal closure and H2O2 production in response to ethylene. Ethylene‐triggered H2O2 generation and stomatal closure were impaired in RAN1, ETR1, ERS1 and EIN4 mutants but not impaired in ETR2 and ERS2 mutants. Gα activator and H2O2 rescued the defect of RAN1 and EIN4 mutants or etr1‐3 in ethylene‐induced H2O2 production and stomatal closure, but only rescued the defect of ERS1 mutants or etr1‐1 and etr1‐9 in ethylene‐induced H2O2 production. Stomata of CTR1 mutants showed constitutive H2O2 production and stomatal closure, but which could be abolished by Gα inhibitor. Stomata of EIN2, EIN3 and ARR2 mutants did not close in responses to ethylene, Gα activator or H2O2, but do generate H2O2 following challenge of ethylene or Gα activator. The data indicate that Gα mediates ethylene‐induced stomatal closure via H2O2 production, and acts downstream of RAN1, ETR1, ERS1, EIN4 and CTR1 and upstream of EIN2, EIN3 and ARR2. The data also show that ETR1 and ERS1 mediate both ethylene and H2O2 signalling in guard cells. 相似文献
13.
Ganesh D. Saratale Rijuta G. Saratale Yung‐Chung Lo Jo‐Shu Chang 《Biotechnology progress》2010,26(2):406-416
Among four cellulolytic microorganisms examined, Cellulomonas biazotea NCIM‐2550 can grow on various cellulosic substrates and produce reducing sugar. The activity of cellulases (endoglucanase, exoglucanase, and cellobiase), xylanase, amylase, and lignin class of enzymes produced by C. biazotea was mainly present extracellularly and the enzyme production was dependent on cellulosic substrates (carboxymethyl cellulose [CMC], sugarcane bagasse [SCB], and xylan) used for growth. Effects of physicochemical conditions on cellulolytic enzyme production were systematically investigated. Using MnCl2 as a metal additive significantly induces the cellulase enzyme system, resulting in more reducing sugar production. The efficiency of fermentative conversion of the hydrolyzed SCB and xylan into clean H2 energy was examined with seven H2‐producing pure bacterial isolates. Only Clostridiumbutyricum CGS5 exhibited efficient H2 production performance with the hydrolysate of SCB and xylan. The cumulative H2 production and H2 yield from using bagasse hydrolysate (initial reducing sugar concentration = 1.545 g/L) were approximately 72.61 mL/L and 2.13 mmol H2/g reducing sugar (or 1.91 mmol H2/g cellulose), respectively. Using xylan hydrolysate (initial reducing sugar concentration = 0.345 g/L) as substrate could also attain a cumulative H2 production and H2 yield of 87.02 mL/L and 5.03 mmol H2/g reducing sugar (or 4.01 mmol H2/g cellulose), respectively. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 相似文献
14.
Bortolami S Comelato E Zoccarato F Alexandre A Cavallini L 《Journal of bioenergetics and biomembranes》2008,40(1):9-18
Complex I is responsible for most of the mitochondrial H2O2 release, low during the oxidation of the NAD linked substrates and high during succinate oxidation, via reverse electron
flow. This H2O2 production appear physiological since it occurs at submillimolar concentrations of succinate also in the presence of NAD
substrates in heart (present work) and rat brain mitochondria (Zoccarato et al., Biochem J, 406:125–129, 2007). Long chain fatty acyl-CoAs, but not fatty acids, act as strong inhibitors of succinate dependent H2O2 release. The inhibitory effect of acyl-CoAs is independent of their oxidation, being relieved by carnitine and unaffected
or potentiated by malonyl-CoA. The inhibition appears to depend on the unbound form since the acyl-CoA effect decreases at
BSA concentrations higher than 2 mg/ml; it is not dependent on ΔpH or Δp and could depend on the inhibition of reverse electron transfer at complex I, since palmitoyl-CoA inhibits the succinate
dependent NAD(P) or acetoacetate reduction. 相似文献
15.
The sustained production of H2 by Chlorella pyrenoidosa was achieved without sulfur deficiency or PSII inhibition. C. pyrenoidosa preserved hydrogenase activity for several hours in the dark. Hydrogenase activity in vitro is O2 sensitive, which indicates that respiration may play an important role in H2 production. A sustainable production of H2 was obtained for 200 h under illumination. Further, by using 3-(3,4-dichlorophenyl)-1,1-dimethylurea as a PSII inhibitor,
at least 70% electrons for H2 production were generated from PSII-catalyzed-H2O oxidation. The remaining electrons were probably from endogenous substrate degradation. 相似文献
16.
SIRT5 inhibits peroxisomal ACOX1 to prevent oxidative damage and is downregulated in liver cancer
下载免费PDF全文
![点击此处可从《EMBO reports》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Xiu‐Fei Chen Meng‐Xin Tian Ren‐Qiang Sun Meng‐Li Zhang Li‐Sha Zhou Lei Jin Lei‐Lei Chen Wen‐Jie Zhou Kun‐Long Duan Yu‐Jia Chen Chao Gao Zhou‐Li Cheng Fang Wang Jin‐Ye Zhang Yi‐Ping Sun Hong‐Xiu Yu Yu‐Zheng Zhao Yi Yang Wei‐Ren Liu Ying‐Hong Shi Yue Xiong Kun‐Liang Guan Dan Ye 《EMBO reports》2018,19(5)
Peroxisomes account for ~35% of total H2O2 generation in mammalian tissues. Peroxisomal ACOX1 (acyl‐CoA oxidase 1) is the first and rate‐limiting enzyme in fatty acid β‐oxidation and a major producer of H2O2. ACOX1 dysfunction is linked to peroxisomal disorders and hepatocarcinogenesis. Here, we show that the deacetylase sirtuin 5 (SIRT5) is present in peroxisomes and that ACOX1 is a physiological substrate of SIRT5. Mechanistically, SIRT5‐mediated desuccinylation inhibits ACOX1 activity by suppressing its active dimer formation in both cultured cells and mouse livers. Deletion of SIRT5 increases H2O2 production and oxidative DNA damage, which can be alleviated by ACOX1 knockdown. We show that SIRT5 downregulation is associated with increased succinylation and activity of ACOX1 and oxidative DNA damage response in hepatocellular carcinoma (HCC). Our study reveals a novel role of SIRT5 in inhibiting peroxisome‐induced oxidative stress, in liver protection, and in suppressing HCC development. 相似文献
17.
The generation of H2O2 in the xylem of Zinnia elegans is mediated by an NADPH-oxidase-like enzyme 总被引:10,自引:0,他引:10
A. Ros Barceló 《Planta》1998,207(2):207-216
The nature of the enzymatic system responsible for the generation of H2O2 in the lignifying xylem of Zinnia elegans (L.) was studied using the starch/KI method for monitoring H2O2 production and the nitroblue tetrazolium method for monitoring superoxide production. The results showed that lignifying xylem
tissues are able to accumulate H2O2 and to sustain H2O2 production. Hydrogen peroxide production in the xylem of Z. elegans was sensitive to pyridine, imidazole, quinacrine and diphenylene iodonium, which are inhibitors of phagocytic plasma-membrane
NADPH oxidase. The sensitivity of H2O2 production to the inhibitor of phospholipase C, neomycin, and to the inhibitor of protein kinase, staurosporine, and its
reversion by the inhibitor of protein phosphatases, cantharidin, pointed to the analogies existing between the mechanism of
H2O2 production in lignifying xylem and the oxidative burst observed during the hypersensitive plant cell response. A further
support for the participation of an NADPH-oxidase-like activity in H2O2 production in lignifying xylem was obtained from the observation that areas of H2O2 production were superimposed on areas producing superoxide anion, the suspected product of NADPH oxidase, although attempts
to demonstrate the existence of superoxide dismutase activity in intercellular washing fluid from Z. elegans were unsuccessful. Even so, the levels of NADPH-oxidase-like activity in microsomal fractions, and of peroxidase in intercellular
washing fluids, are consistent with a role for NADPH oxidase in the delivery of H2O2 which may be further used by xylem peroxidases for the synthesis of lignins. This hypothesis was further confirmed through
a direct histochemical probe based on the H2O2-dependent oxidation of tetramethylbenzidine by xylem cell wall peroxidases. These results are the first evidence for the
existence of an NADPH oxidase responsible for supplying H2O2 to peroxidase in the lignifying xylem of Z. elegans.
Received: 6 February 1998 / Accepted: 14 August 1998 相似文献
18.
A photoinduced H2 production system, coupling d-maltose degradation by glucoamylase and glucose dehydrogenase (GDH) and H2 production with colloidal platinum as a catalyst using the visible light-induced photosensitization of Mg chlorophyll-a (Mg Chl-a), has been developed. H2 production was continuous when the reaction mixture containing d-maltose, glucoamylase, GDH, NAD+, Mg Chl-a, Methyl Viologen (MV2+, an electron relay reagent) and colloidal platinum was irradiated by visible light. The amount of H2 production was estimated to be 5 ± 0.5 mol after 4 h irradiation. The yield of the conversion of d-maltose to H2 in this system was ca. 1.8 %. 相似文献
19.
XIN LI JIAN‐HUA LI WEI WANG NAI‐ZHI CHEN TONG‐SUO MA YA‐NAN XI XIAO‐LU ZHANG HAI‐FEI LIN YANG BAI SHAN‐JIN HUANG YU‐LING CHEN 《Plant, cell & environment》2014,37(7):1548-1560
Multiple cellular events like dynamic actin reorganization and hydrogen peroxide (H2O2) production were demonstrated to be involved in abscisic acid (ABA)‐induced stomatal closure. However, the relationship between them as well as the underlying mechanisms remains poorly understood. Here, we showed that H2O2 generation is indispensable for ABA induction of actin reorganization in guard cells of Arabidopsis that requires the presence of ARP2/3 complex. H2O2‐induced stomatal closure was delayed in the mutants of arpc4 and arpc5, and the rate of actin reorganization was slowed down in arpc4 and arpc5 in response to H2O2, suggesting that ARP2/3‐mediated actin nucleation is required for H2O2‐induced actin cytoskeleton remodelling. Furthermore, the expression of H2O2 biosynthetic related gene AtrbohD and the accumulation of H2O2 was delayed in response to ABA in arpc4 and arpc5, demonstrating that misregulated actin dynamics affects H2O2 production upon ABA treatment. These results support a possible causal relation between the production of H2O2 and actin dynamics in ABA‐mediated guard cell signalling: ABA triggers H2O2 generation that causes the reorganization of the actin cytoskeleton partially mediated by ARP2/3 complex, and ARP2/3 complex‐mediated actin dynamics may feedback regulate H2O2 production. 相似文献
20.
The hyperthermophilic bacterium, Thermotoga neapolitana, has potential for use in biological hydrogen (H2) production. The objectives of this study were to (1) determine the fermentation stoichiometry of Thermotoga neapolitana and examine H2 production at various growth temperatures, (2) investigate the effect of oxygen (O2) on H2 production, and (3) determine the cause of glucose consumption inhibition. Batch fermentation experiments were conducted at temperatures of 60, 65, 70, 77, and 85°C to determine product yield coefficients and volumetric productivity rates. Yield coefficients did not show significant changes with respect to growth temperature and the rate of H2 production reached maximum levels in both the 77°C and 85°C experiments. The fermentation stoichiometry for T. neapolitana at 85°C was 3.8 mol H2, 2 mol CO2, 1.8 mol acetate, and 0.1 mol lactate produced per mol of glucose consumed. Under microaerobic conditions H2 production did not increase when compared to anaerobic conditions, which supports other evidence in the literature that T. neapolitana does not produce H2 through microaerobic metabolism. Glucose consumption was inhibited by a decrease in pH. When pH was adjusted with buffer addition cultures completely consumed available glucose. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 相似文献