Stimulus-specific accumulation of second messengers like reactive oxygen species （ROS） and Ca^＋ are central to many signaling and regulation processes in plants. However, mechanisms that govern the reciprocal inter...Stimulus-specific accumulation of second messengers like reactive oxygen species （ROS） and Ca^＋ are central to many signaling and regulation processes in plants. However, mechanisms that govern the reciprocal interrelation of Ca^＋ and ROS signaling are only beginning to emerge. NADPH oxidases of the respiratory burst oxidase homolog （RBOH） family are critical components contributing to the generation of ROS while Calcineurin B-like （CBL） Ca^＋ sensor proteins together with their interacting kinases （CIPKs） have been shown to function in many Ca^＋- signaling processes. In this study, we identify direct functional interactions between both signaling systems. We report that the CBL-interacting pro- tein kinase ClPK26 specifically interacts with the N-terminal domain of RBOHF in yeast two-hybrid analyses and with the full-length RBOHF protein in plant cells. In addition, CIPK26 phosphorylates RBOHF in vitro and co-expression of either CBL1 or CBL9 with CIPK26 strongly enhances ROS production by RBOHF in HEK293T cells. Together, these findings identify a direct interconnection between CBL-ClPK-mediated Ca^＋ signaling and ROS signaling in plants and provide evidence for a synergistic activation of the NADPH oxidase RBOHF by direct Ca^＋-binding to its EF-hands and Ca2＋-induced phospho-rylation by CBL1/9-ClPK26 complexes.展开更多
Lesion mimic is necrotic lesions on plant leaf or stem in the absence of pathogenic infection, and its exact biological mechanism is varied. By a large-scale screening of our T-DNA mutant population, we identified a m...Lesion mimic is necrotic lesions on plant leaf or stem in the absence of pathogenic infection, and its exact biological mechanism is varied. By a large-scale screening of our T-DNA mutant population, we identified a mutant rice lesion initiation 1 （rlin1）, which was controlled by a single nuclear recessive gene. Map-based cloning revealed that RLIN1 encoded a putative coproporphyrinogen Ⅲ oxidase in tetrapyrrole biosynthesis pathway. Sequencing results showed that a G to T substitution occurred in the second exon of RLIN1 and led to a missense mutation from Asp to Tyr. Ectopic expression of RLIN1 could rescue rlin1 lesion mimic phenotype. Histochemical analysis demonstrated that lesion formation in rlin1 was light-dependent accompanied by reactive oxygen species accumulated. These results suggest that tetrapyrrole participates in lesion formation in rice.展开更多
BACKGROUND: Plasma D(-)-lactate and diamine oxidase (DAO) can reflect patients' intestinal mucosal condition. We evaluated the changes of plasma D (-)-lactate, DAO and endotoxin activities and their significance i...BACKGROUND: Plasma D(-)-lactate and diamine oxidase (DAO) can reflect patients' intestinal mucosal condition. We evaluated the changes of plasma D (-)-lactate, DAO and endotoxin activities and their significance in patients with liver cirrhosis. METHODS: Fifty liver cirrhosis patients were enrolled into experimental group and 30 healthy people into control group. The plasma levels of D(-)-lactate, DAO and endo- toxin were detected spectrophotographically. RESULTS: The level of D(-)-lactate was significantly high- er in the experimental group than that in the control group (P<0.01). Significant differences of D (-)-lactate levels were observed in Child-Pugh subgroups of the experimen- tal group (P <0. 01). The level of DAO was significantly higher in the experimental group than that in the control group (P <0.01), but the level of DAO in Child-Pugh sub- group C was significantly lower than that in Child-Pugh subgroup B (P<0.01). The level of endotoxin was signifi- cantly increased in the experimental group except Child Pugh subgroup A (P<0.01). The plasma levels of D(-) lactate, DAO and endotoxin were positively correlated with each other (P<0.01). CONCLUSIONS: The data suggest that both plasma D(-) lactate and DAO activity are sensitive markers for early diagnosis of gut failure and endotoxemia in patients with liver cirrhosis. The impairment of intestinal barrier func- tion may be one of the critical reasons for deterioration of liver cirrhosis.展开更多
Alcaligenes faecalis C16 was found to have the ability to heterotrophically nitrify and aerobically denitrify. In order to further understand its nitrogen removal ability and mechanism, the growth and ammonium removal...Alcaligenes faecalis C16 was found to have the ability to heterotrophically nitrify and aerobically denitrify. In order to further understand its nitrogen removal ability and mechanism, the growth and ammonium removal response were investigated at different C/N ratios and ammonium concentrations in the medium with citrate and acetate as carbon source separately. Furthermore, experiments of nitrogen sources, production of nitrogen gas and enzyme assay were conducted. Results show that the bacterium converts NH+4-N and produces NH2 OH during the growing phase and nitrite accumulation is its distinct metabolic feature. A. faecalis C16 is able to tolerate not only high ammonium concentration but also high C/N ratio, and the ammonium tolerance is associated with carbon source and C/N ratio. The nitrogen balance under different conditions shows that approximately28%–45% of the initial ammonium is assimilated into the cells, 44%–60% is denitrified and several percent is converted to nitrification products. A. faecalis C16 cannot utilize hydroxylamine, nitrite or nitrate as the sole nitrogen source for growth. However, nitrate can be used when ammonium is simultaneously present in the medium. A possible pathway for nitrogen removal by C16 is suggested. The preliminary enzyme assay provides more evidence for this nitrogen removal pathway.展开更多
Indeed,medicinal importance of honey has been documented in the world's oldest medical literatures,and since the ancient times,it has been known to possess antimicrobial property as well as wound-healing activity....Indeed,medicinal importance of honey has been documented in the world's oldest medical literatures,and since the ancient times,it has been known to possess antimicrobial property as well as wound-healing activity.The healing property of honey is due to the fact that it offers antibacterial activity,maintains a moist wound condition,and its high viscosity helps to provide a protective barrier to prevent infection.Its immunomodulatory property is relevant to wound repair too.The antimicrobial activity in most honeys is due to the enzymatic production of hydrogen peroxide.However,another kind of honey,called non-peroxide honey(viz.,manuka honey),displays significant antibacterial effects even when the hydrogen peroxide activity is blocked.Its mechanism may be related to the low pH level of honey and its high sugar content(high osmolality) that is enough to hinder the growth of microbes.The medical grade honeys have potent in vitro bactericidal activity against antibiotic-resistant bacteria causing several life-threatening infections to humans. But,there is a large variation in the antimicrobial activity of some natural honeys,which is due to spatial and temporal variation in sources of nectar.Thus,identification and characterization of the active principle(s) may provide valuable information on the quality and possible therapeutic potential of honeys(against several health disorders of humans),and hence we discussed the medicinal property of honeys with emphasis on their antibacterial activities.展开更多
The article investigated the changes of nutrients(total sugar,total nitrogen,total sugar/total N)and oxidases(IAAO,POD,PPO)of Catalpa bungei cl.’Yu-1’ in the cutting rooting process.The results showed that:C.bungei ...The article investigated the changes of nutrients(total sugar,total nitrogen,total sugar/total N)and oxidases(IAAO,POD,PPO)of Catalpa bungei cl.’Yu-1’ in the cutting rooting process.The results showed that:C.bungei cl.’Yu-1’ cutting rooting initiated from the lenticel.The soluble protein in the forced-sprouting cuttings decreased dramatically in the early stage,and then the decrease tended to slow.The total sugar content slowly increased throughout.The total nitrogen had a little change.The total sugar/total nitrogen ratio had same trend with total sugar.The IAAO,PPO activity of the forced-sprouting cuttings showed up-down-up-down pattern in the rooting process,The POD activity rose in undulation pattern.The role of three oxidases was both independent with each other,and related to one another in the process of rooting by which affected rooting in integration.展开更多
BACKGROUND： The gut is capable of inducing multiple organ dysfunction syndrome （MODS）. In the diagnosis and treatment of critical ill patients, doctors should pay particular attention to the protection or recovery ...BACKGROUND： The gut is capable of inducing multiple organ dysfunction syndrome （MODS）. In the diagnosis and treatment of critical ill patients, doctors should pay particular attention to the protection or recovery of intestinal barrier function. However, no reliable diagnostic criteria are available clinically. This study aimed to assess the changes of intestinal mucosal barrier function in surgically critical ill patients as well as their signi？ cance.METHODS： Thirty-eight surgically critical ill patients were enrolled as a study group （APACHE II〉8 scores）, and 15 non-critical ill patients without intestinal dysfunction were selected as a control group （APACHE II〈6）. General information, symptoms, physical signs, and APACHE II scores of the patients were recorded. The patients in the study group were subdivided into an intestinal dysfunction group （n=26） and a non-intestinal dysfunction group （n=12）. Three ml venous blood was collected from the control group on admission and the same volume of plasma was collected from the study group both on admission and in the period of recovery. The plasma concentrations of endotoxin, diamine oxidase （DAO）, D-lactate, and intestinal fatty-acid binding protein （iFABP） were detected respectively. The data collected were analyzed by the SPSS 17.0 software for Windows. RESULTS： The levels of variables were significantly higher in the study group than in the control group （P〈0.01）. They were higher in the intestinal dysfunction group than in the non-intestinal dysfunction group （DAO P〈0.05, endotoxin, D-lactate, iFABP P〈0.01）. In the non-intestinal dysfunction group compared with the control group, the level of endotoxin was not significant （P〉0.05）, but the levels of DAO, D-lactate and iFABP were statistically significant （P〈0.05）. The levels of variables in acute stage were higher than those in recovery stage （P〈0.01）.The death group showed higher levels of variables than the survival group （endotoxin a展开更多
Hyperuricemia have been thought to be caused by the ingestion of large amounts of purines, and prevention or treatment of hyperuricemia has intended to prevent gout. Xanthine dehydrogenase/xanthine oxidase(XDH/XO) is ...Hyperuricemia have been thought to be caused by the ingestion of large amounts of purines, and prevention or treatment of hyperuricemia has intended to prevent gout. Xanthine dehydrogenase/xanthine oxidase(XDH/XO) is rate-limiting enzyme of uric acid generation, and allopurinol was developed as a uric acid(UA) generation inhibitor in the 1950 s and has been routinely used for gout prevention since then. Serum UA levels are an important risk factor of disease progression for various diseases, including those related to lifestyle. Recently, other UA generation inhibitors such as febuxostat and topiroxostat were launched. The emergence of these novel medications has promoted new research in the field. Lifestyle-related diseases, such as metabolic syndrome or type 2 diabetes mellitus, often have a common pathological foundation. As such, hyperuricemia is often present among these patients. Many in vitro and animal studies have implicated inflammation and oxidative stress in UA metabolism and vascular injury because XDH/XO act as one of the major source of reactive oxygen species Many studies on UA levels and associated diseases implicate involvement of UA generation in disease onset and/or progression. Interventional studies for UA generation, not UA excretion revealed XDH/XO can be the therapeutic target forvascular injury and renal dysfunction. In this review, the relationship between UA metabolism and diabetic complications is highlighted.展开更多
AIM： To study the levels of serum soluble intercellular adhesion molecule-1 （sICAM-1）, plasma D-lactate and diamine oxidase （DAO） in patients with inflammatory bowel disease （IBD）, and the potential clinical si...AIM： To study the levels of serum soluble intercellular adhesion molecule-1 （sICAM-1）, plasma D-lactate and diamine oxidase （DAO） in patients with inflammatory bowel disease （IBD）, and the potential clinical significance. METHODS： Sixty-nine patients with IBD and 30 healthy controls were included in this study. The concentration of sICAM-1 was detected with enzyme-linked immunosorbent assay, the level of D-lactate and DAO was measured by spectroscopic analysis, and the number of white blood cells （WBC） was determined by routine procedure. RESULTS： The levels of sICAM-I, DAO, and WBC in IBD patients were significantly higher than those in the control group （P 〈 0,01）, sICAM-I in IBD patients was found to be closely related to the levels of DAO and D-lactate （212.94 ± 69.89 vs 6.35 ± 2.35, P = 0.000）, DAO 212.94 ± 69.89 vs 8.65 ± 3.54, P = 0.000） and WBC （212.94 ± 69.89 vs 7.40 ± 2.61, P = 0.000）, but no significant difference was observed between patients with ulcerative colitis and patients with Crohn＇s disease. The post-treatment levels of sICAM-I, D-lactate and WBC were significantly lower than before treatment （sICAM-I 206.57 ± 79.21 vs 146.21 ± 64.43, P = 0.000）, （D-lactate 1.46 ± 0.94 vs 0.52± 0.32, P = 0.000） and （WBC 7.24 ± 0.2.33 vs 5.21 ± 3.21, P = 0.000）. CONCLUSION： sICAM-1, D-lactate and DAO are closely related to the specific conditions of IBD, and thus could be used as a major diagnostic index.展开更多
Recent data implicate oxidative stress as a mediator of pulmonary hypertension (PH) and of the associated pathological changes to the pulmonary vasculature and right ventricle (RV). Increases in reactive oxygen specie...Recent data implicate oxidative stress as a mediator of pulmonary hypertension (PH) and of the associated pathological changes to the pulmonary vasculature and right ventricle (RV). Increases in reactive oxygen species (ROS), altered redox state, and elevated oxidant stress have been demonstrated in the lungs and RV of several animal models of PH, including chronic hypoxia, monocrotaline toxicity, caveolin-1 knock-out mouse, and the transgenic Ren2 rat which overexpresses the mouse renin gene. Generation of ROS in these models is derived mostly from the activities of the nicotinamide adenine dinucleotide phosphate oxidases, xanthine oxidase, and uncoupled endothelial nitric oxide synthase. As disease progresses circulating monocytes and bone marrow-derived monocytic progenitor cells are attracted to and accumulate in the pulmonary vasculature. Once established, these inflammatory cells generate ROS and secrete mitogenic and fibrogenic cytokines that induce cell proliferation and fibrosis in the vascular wall resulting in progressive vascular remodeling. Deficiencies in antioxidant enzymes also contribute to pulmonary hypertensive states. Current therapies were developed to improve endothelial function, reduce pulmonary artery pressure, and slow the progression of vascular remodeling in the pulmonary vasculature by targeting deficiencies in either NO (PDE-type 5 inhibition) or PGI 2 (prostacyclin analogs), or excessive synthesis of ET-1 (ET receptor blockers) with the intent to improve patient clinical status and survival. New therapies may slow disease progression to some extent, but long term management has not been achieved and mortality is still high. Although little is known concerning the effects of current pulmonary arterial hypertension treatments on RV structure and function, interest in this area is increasing. Development of therapeutic strategies that simultaneously target pathology in the pulmonary vasculature and RV may be beneficial in reducing mortality associated with RV failure.展开更多
The purpose of this paper is to investigate the differential responses of flower opening to ethylene in two cut rose cultivars, ‘Samantha’, whose opening process is promoted, and ‘Kardinal’, whose opening process ...The purpose of this paper is to investigate the differential responses of flower opening to ethylene in two cut rose cultivars, ‘Samantha’, whose opening process is promoted, and ‘Kardinal’, whose opening process is inhibited by ethylene. Ethylene production and 1- aminocyclopropane-1-carboxylate (ACC) synthase and oxidase activities were determined first. After ethylene treatment, ethylene production, ACC synthase (ACS) and ACC oxidase (ACO) activities in petals increased and peaked at the earlier stage (stage 3) in ‘Samantha’, and they were much more dramatically enhanced and peaked at the later stage (stage 4) in ‘Kardinal’ than control during vasing. cDNA fragments of three Rh-ACSs and one Rh- ACO genes were cloned and designated as Rh-ACS1, Rh-ACS2, Rh-ACS3 and Rh-ACO1 respectively. Northern blotting analysis revealed that, among three genes of ACS, ethylene-in- duced expression patterns of Rh-ACS3 gene corresponded to ACS activity and ethylene production in both cultivars. A more dramatic accumulation of Rh-ACS3 mRNA was induced by ethylene in ‘Kardinal’ than that of ‘Samantha’. As an ethylene action inhibitor, STS at concentration of 0.2 mmol/L generally inhib-ited the expression of Rh-ACSs and Rh-ACO in both cultivars, although it induced the expression of Rh-ACS3 transiently in ‘Kardinal’. Our results suggests that ‘Kardinal’ is more sensitive to ethylene than ‘Samantha’; and the changes of Rh-ACS3 expression caused by ethylene might be related to the acceleration of flower opening in ‘Samantha’ and the inhibition in ‘Kardinal’. Additional results indicated that three Rh-ACSs genes were differentially associated with flower opening and senescence as well as wounding.展开更多
Rapid and dynamic change in hydrogen peroxide （H2O2） levels can serve as an important signal to regulate various biological processes in plants. The change is realized by tilting the balance between its production a...Rapid and dynamic change in hydrogen peroxide （H2O2） levels can serve as an important signal to regulate various biological processes in plants. The change is realized by tilting the balance between its production and scavenging rates, in which membrane-associated NADPH oxidases are known to play a crucial role. Functioning independently from NADPH oxidases, glycolate oxidase （GLO） was recently demonstrated as an aitemative source for H2O2 production during both germ-for-germ and non-host resistance in plants. In this study, we show that GLO physically interacts with catalase （CAT） in rice leaves, and that the interaction can be deregulated by salicylic acid （SA）. Furthermore, the GLO-mediated H2O2 accumulation is synergistically enhanced by SA. Based on the well-known mechanism of substrate channeling in enzyme complexes, SA-induced H2O2 accumulation likely results from SA-induced GLO-CAT dissociation. In the GLO-CAT complex, GLO-mediated H2O2 production during photorespiration is very high, whereas the affinity of CAT for H2O2 （measured Km ≈ 43 raM） is extraordinarily low. This unique combination can further potentiate the increase in H2O2 when GLO is dissociated from CAT. Taken together, we propose that the physical association-dissociation of GLO and CAT, in response to environmental stress or stimuli, seems to serve as a specific mechanism to modulate H2O2 levels in rice.展开更多
We analyzed 20 chemosensory protein （CSP） genes of the silkworm Bombyx mori. We found a high number of retrotransposons inserted in introns. We then analyzed expression of the 20 BrnorCSP genes across tissues using ...We analyzed 20 chemosensory protein （CSP） genes of the silkworm Bombyx mori. We found a high number of retrotransposons inserted in introns. We then analyzed expression of the 20 BrnorCSP genes across tissues using quantitative real-time polymerase chain reaction （PCR）. Relatively low expression levels of BmorCSPs were found in the gut and fat body tissues. We thus tested the effects of endectocyte insecticide abamectin （B 1 a and Blb avermectins） on BmorCSP gene expression. Quantitative real-time PCR experi- ments showed that a single brief exposure to insecticide abamectin increased dramatically CSP expression not only in the antennae but in most tissues, including gut and fat body. Furthermore, our study showed coordinate expression of CSPs and metabolic cytochrome P450 enzymes in a tissue-dependent manner in response to the insecticide. The function of CSPs remains unknown. Based on our results, we suggest a role in detecting xenobiotics that are then detoxified by cytochrome P450 anti-xenobiotic enzymes.展开更多
Sex determination in plants gives rise to unisexual flowers that facilitate outcrossing and enhance genetic diversity. In cucumber and melon, ethylene promotes carpel development and arrests sta- men development. Five...Sex determination in plants gives rise to unisexual flowers that facilitate outcrossing and enhance genetic diversity. In cucumber and melon, ethylene promotes carpel development and arrests sta- men development. Five sex-determination genes have been identified, including four encoding 1-aminocyclopropane-l-carboxylate （ACC） synthase that catalyzes the rate-limiting step in ethylene biosynthesis, and a transcription factor gene CmWIP1 that corresponds to the Mendelian locus gynoecious in melon and is a negative regulator of femaleness. ACC oxidase （ACO） converts ACC into ethylene; how- ever, it remains elusive which ACO gene in the cucumber genome is critical for sex determination and how CmWIP1 represses development of female flowers. In this study, we discovered that mutation in an ACO gene, CsAC02, confers androecy in cucumber that bears only male flowers. The mutation disrupts the enzymatic activity of CsAC02, resulting in 50% less ethylene emission from shoot tips. CsAC02 was ex- pressed in the carpel primordia and its expression overlapped with that of CsACS11 in female flowers at key stages for sex determination, presumably providing sufficient ethylene required for proper CsACS2 expression. CmAC03, the ortholog of CsACO2, showed a similar expression pattern in the carpel region, suggesting a conserved function of CsACO2/CmACO3. We demonstrated that CsWlP1, the ortholog of CmWlP1, could directly bind the promoter of CsAC02 and repress its expression. Taken together, we propose a presumably conserved regulatory module consisting of WlP1 transcription factor and ACO controls unisexual flower development in cucumber and melon.展开更多
文摘Stimulus-specific accumulation of second messengers like reactive oxygen species （ROS） and Ca^＋ are central to many signaling and regulation processes in plants. However, mechanisms that govern the reciprocal interrelation of Ca^＋ and ROS signaling are only beginning to emerge. NADPH oxidases of the respiratory burst oxidase homolog （RBOH） family are critical components contributing to the generation of ROS while Calcineurin B-like （CBL） Ca^＋ sensor proteins together with their interacting kinases （CIPKs） have been shown to function in many Ca^＋- signaling processes. In this study, we identify direct functional interactions between both signaling systems. We report that the CBL-interacting pro- tein kinase ClPK26 specifically interacts with the N-terminal domain of RBOHF in yeast two-hybrid analyses and with the full-length RBOHF protein in plant cells. In addition, CIPK26 phosphorylates RBOHF in vitro and co-expression of either CBL1 or CBL9 with CIPK26 strongly enhances ROS production by RBOHF in HEK293T cells. Together, these findings identify a direct interconnection between CBL-ClPK-mediated Ca^＋ signaling and ROS signaling in plants and provide evidence for a synergistic activation of the NADPH oxidase RBOHF by direct Ca^＋-binding to its EF-hands and Ca2＋-induced phospho-rylation by CBL1/9-ClPK26 complexes.
基金This work was supported by grants from the Ministry of Science and Technology of China(No.2009CB118506)the National Natural Science Foundation of China(Nos. 30825029 and 30621001)
文摘Lesion mimic is necrotic lesions on plant leaf or stem in the absence of pathogenic infection, and its exact biological mechanism is varied. By a large-scale screening of our T-DNA mutant population, we identified a mutant rice lesion initiation 1 （rlin1）, which was controlled by a single nuclear recessive gene. Map-based cloning revealed that RLIN1 encoded a putative coproporphyrinogen Ⅲ oxidase in tetrapyrrole biosynthesis pathway. Sequencing results showed that a G to T substitution occurred in the second exon of RLIN1 and led to a missense mutation from Asp to Tyr. Ectopic expression of RLIN1 could rescue rlin1 lesion mimic phenotype. Histochemical analysis demonstrated that lesion formation in rlin1 was light-dependent accompanied by reactive oxygen species accumulated. These results suggest that tetrapyrrole participates in lesion formation in rice.
文摘BACKGROUND: Plasma D(-)-lactate and diamine oxidase (DAO) can reflect patients' intestinal mucosal condition. We evaluated the changes of plasma D (-)-lactate, DAO and endotoxin activities and their significance in patients with liver cirrhosis. METHODS: Fifty liver cirrhosis patients were enrolled into experimental group and 30 healthy people into control group. The plasma levels of D(-)-lactate, DAO and endo- toxin were detected spectrophotographically. RESULTS: The level of D(-)-lactate was significantly high- er in the experimental group than that in the control group (P<0.01). Significant differences of D (-)-lactate levels were observed in Child-Pugh subgroups of the experimen- tal group (P <0. 01). The level of DAO was significantly higher in the experimental group than that in the control group (P <0.01), but the level of DAO in Child-Pugh sub- group C was significantly lower than that in Child-Pugh subgroup B (P<0.01). The level of endotoxin was signifi- cantly increased in the experimental group except Child Pugh subgroup A (P<0.01). The plasma levels of D(-) lactate, DAO and endotoxin were positively correlated with each other (P<0.01). CONCLUSIONS: The data suggest that both plasma D(-) lactate and DAO activity are sensitive markers for early diagnosis of gut failure and endotoxemia in patients with liver cirrhosis. The impairment of intestinal barrier func- tion may be one of the critical reasons for deterioration of liver cirrhosis.
基金National Natural Science Foundation of China(51078252)the Science and Technology Program of Taiyuan(120233)the Natural Science Foundation of Shanxi Province(2010011016–1)
文摘Alcaligenes faecalis C16 was found to have the ability to heterotrophically nitrify and aerobically denitrify. In order to further understand its nitrogen removal ability and mechanism, the growth and ammonium removal response were investigated at different C/N ratios and ammonium concentrations in the medium with citrate and acetate as carbon source separately. Furthermore, experiments of nitrogen sources, production of nitrogen gas and enzyme assay were conducted. Results show that the bacterium converts NH+4-N and produces NH2 OH during the growing phase and nitrite accumulation is its distinct metabolic feature. A. faecalis C16 is able to tolerate not only high ammonium concentration but also high C/N ratio, and the ammonium tolerance is associated with carbon source and C/N ratio. The nitrogen balance under different conditions shows that approximately28%–45% of the initial ammonium is assimilated into the cells, 44%–60% is denitrified and several percent is converted to nitrification products. A. faecalis C16 cannot utilize hydroxylamine, nitrite or nitrate as the sole nitrogen source for growth. However, nitrate can be used when ammonium is simultaneously present in the medium. A possible pathway for nitrogen removal by C16 is suggested. The preliminary enzyme assay provides more evidence for this nitrogen removal pathway.
文摘Indeed,medicinal importance of honey has been documented in the world's oldest medical literatures,and since the ancient times,it has been known to possess antimicrobial property as well as wound-healing activity.The healing property of honey is due to the fact that it offers antibacterial activity,maintains a moist wound condition,and its high viscosity helps to provide a protective barrier to prevent infection.Its immunomodulatory property is relevant to wound repair too.The antimicrobial activity in most honeys is due to the enzymatic production of hydrogen peroxide.However,another kind of honey,called non-peroxide honey(viz.,manuka honey),displays significant antibacterial effects even when the hydrogen peroxide activity is blocked.Its mechanism may be related to the low pH level of honey and its high sugar content(high osmolality) that is enough to hinder the growth of microbes.The medical grade honeys have potent in vitro bactericidal activity against antibiotic-resistant bacteria causing several life-threatening infections to humans. But,there is a large variation in the antimicrobial activity of some natural honeys,which is due to spatial and temporal variation in sources of nectar.Thus,identification and characterization of the active principle(s) may provide valuable information on the quality and possible therapeutic potential of honeys(against several health disorders of humans),and hence we discussed the medicinal property of honeys with emphasis on their antibacterial activities.
文摘The article investigated the changes of nutrients(total sugar,total nitrogen,total sugar/total N)and oxidases(IAAO,POD,PPO)of Catalpa bungei cl.’Yu-1’ in the cutting rooting process.The results showed that:C.bungei cl.’Yu-1’ cutting rooting initiated from the lenticel.The soluble protein in the forced-sprouting cuttings decreased dramatically in the early stage,and then the decrease tended to slow.The total sugar content slowly increased throughout.The total nitrogen had a little change.The total sugar/total nitrogen ratio had same trend with total sugar.The IAAO,PPO activity of the forced-sprouting cuttings showed up-down-up-down pattern in the rooting process,The POD activity rose in undulation pattern.The role of three oxidases was both independent with each other,and related to one another in the process of rooting by which affected rooting in integration.
文摘BACKGROUND： The gut is capable of inducing multiple organ dysfunction syndrome （MODS）. In the diagnosis and treatment of critical ill patients, doctors should pay particular attention to the protection or recovery of intestinal barrier function. However, no reliable diagnostic criteria are available clinically. This study aimed to assess the changes of intestinal mucosal barrier function in surgically critical ill patients as well as their signi？ cance.METHODS： Thirty-eight surgically critical ill patients were enrolled as a study group （APACHE II〉8 scores）, and 15 non-critical ill patients without intestinal dysfunction were selected as a control group （APACHE II〈6）. General information, symptoms, physical signs, and APACHE II scores of the patients were recorded. The patients in the study group were subdivided into an intestinal dysfunction group （n=26） and a non-intestinal dysfunction group （n=12）. Three ml venous blood was collected from the control group on admission and the same volume of plasma was collected from the study group both on admission and in the period of recovery. The plasma concentrations of endotoxin, diamine oxidase （DAO）, D-lactate, and intestinal fatty-acid binding protein （iFABP） were detected respectively. The data collected were analyzed by the SPSS 17.0 software for Windows. RESULTS： The levels of variables were significantly higher in the study group than in the control group （P〈0.01）. They were higher in the intestinal dysfunction group than in the non-intestinal dysfunction group （DAO P〈0.05, endotoxin, D-lactate, iFABP P〈0.01）. In the non-intestinal dysfunction group compared with the control group, the level of endotoxin was not significant （P〉0.05）, but the levels of DAO, D-lactate and iFABP were statistically significant （P〈0.05）. The levels of variables in acute stage were higher than those in recovery stage （P〈0.01）.The death group showed higher levels of variables than the survival group （endotoxin a
文摘Hyperuricemia have been thought to be caused by the ingestion of large amounts of purines, and prevention or treatment of hyperuricemia has intended to prevent gout. Xanthine dehydrogenase/xanthine oxidase(XDH/XO) is rate-limiting enzyme of uric acid generation, and allopurinol was developed as a uric acid(UA) generation inhibitor in the 1950 s and has been routinely used for gout prevention since then. Serum UA levels are an important risk factor of disease progression for various diseases, including those related to lifestyle. Recently, other UA generation inhibitors such as febuxostat and topiroxostat were launched. The emergence of these novel medications has promoted new research in the field. Lifestyle-related diseases, such as metabolic syndrome or type 2 diabetes mellitus, often have a common pathological foundation. As such, hyperuricemia is often present among these patients. Many in vitro and animal studies have implicated inflammation and oxidative stress in UA metabolism and vascular injury because XDH/XO act as one of the major source of reactive oxygen species Many studies on UA levels and associated diseases implicate involvement of UA generation in disease onset and/or progression. Interventional studies for UA generation, not UA excretion revealed XDH/XO can be the therapeutic target forvascular injury and renal dysfunction. In this review, the relationship between UA metabolism and diabetic complications is highlighted.
文摘AIM： To study the levels of serum soluble intercellular adhesion molecule-1 （sICAM-1）, plasma D-lactate and diamine oxidase （DAO） in patients with inflammatory bowel disease （IBD）, and the potential clinical significance. METHODS： Sixty-nine patients with IBD and 30 healthy controls were included in this study. The concentration of sICAM-1 was detected with enzyme-linked immunosorbent assay, the level of D-lactate and DAO was measured by spectroscopic analysis, and the number of white blood cells （WBC） was determined by routine procedure. RESULTS： The levels of sICAM-I, DAO, and WBC in IBD patients were significantly higher than those in the control group （P 〈 0,01）, sICAM-I in IBD patients was found to be closely related to the levels of DAO and D-lactate （212.94 ± 69.89 vs 6.35 ± 2.35, P = 0.000）, DAO 212.94 ± 69.89 vs 8.65 ± 3.54, P = 0.000） and WBC （212.94 ± 69.89 vs 7.40 ± 2.61, P = 0.000）, but no significant difference was observed between patients with ulcerative colitis and patients with Crohn＇s disease. The post-treatment levels of sICAM-I, D-lactate and WBC were significantly lower than before treatment （sICAM-I 206.57 ± 79.21 vs 146.21 ± 64.43, P = 0.000）, （D-lactate 1.46 ± 0.94 vs 0.52± 0.32, P = 0.000） and （WBC 7.24 ± 0.2.33 vs 5.21 ± 3.21, P = 0.000）. CONCLUSION： sICAM-1, D-lactate and DAO are closely related to the specific conditions of IBD, and thus could be used as a major diagnostic index.
文摘Recent data implicate oxidative stress as a mediator of pulmonary hypertension (PH) and of the associated pathological changes to the pulmonary vasculature and right ventricle (RV). Increases in reactive oxygen species (ROS), altered redox state, and elevated oxidant stress have been demonstrated in the lungs and RV of several animal models of PH, including chronic hypoxia, monocrotaline toxicity, caveolin-1 knock-out mouse, and the transgenic Ren2 rat which overexpresses the mouse renin gene. Generation of ROS in these models is derived mostly from the activities of the nicotinamide adenine dinucleotide phosphate oxidases, xanthine oxidase, and uncoupled endothelial nitric oxide synthase. As disease progresses circulating monocytes and bone marrow-derived monocytic progenitor cells are attracted to and accumulate in the pulmonary vasculature. Once established, these inflammatory cells generate ROS and secrete mitogenic and fibrogenic cytokines that induce cell proliferation and fibrosis in the vascular wall resulting in progressive vascular remodeling. Deficiencies in antioxidant enzymes also contribute to pulmonary hypertensive states. Current therapies were developed to improve endothelial function, reduce pulmonary artery pressure, and slow the progression of vascular remodeling in the pulmonary vasculature by targeting deficiencies in either NO (PDE-type 5 inhibition) or PGI 2 (prostacyclin analogs), or excessive synthesis of ET-1 (ET receptor blockers) with the intent to improve patient clinical status and survival. New therapies may slow disease progression to some extent, but long term management has not been achieved and mortality is still high. Although little is known concerning the effects of current pulmonary arterial hypertension treatments on RV structure and function, interest in this area is increasing. Development of therapeutic strategies that simultaneously target pathology in the pulmonary vasculature and RV may be beneficial in reducing mortality associated with RV failure.
基金This work was supported by the Nat ional Natural Science Foundation of China(Grant No.30471220).
文摘The purpose of this paper is to investigate the differential responses of flower opening to ethylene in two cut rose cultivars, ‘Samantha’, whose opening process is promoted, and ‘Kardinal’, whose opening process is inhibited by ethylene. Ethylene production and 1- aminocyclopropane-1-carboxylate (ACC) synthase and oxidase activities were determined first. After ethylene treatment, ethylene production, ACC synthase (ACS) and ACC oxidase (ACO) activities in petals increased and peaked at the earlier stage (stage 3) in ‘Samantha’, and they were much more dramatically enhanced and peaked at the later stage (stage 4) in ‘Kardinal’ than control during vasing. cDNA fragments of three Rh-ACSs and one Rh- ACO genes were cloned and designated as Rh-ACS1, Rh-ACS2, Rh-ACS3 and Rh-ACO1 respectively. Northern blotting analysis revealed that, among three genes of ACS, ethylene-in- duced expression patterns of Rh-ACS3 gene corresponded to ACS activity and ethylene production in both cultivars. A more dramatic accumulation of Rh-ACS3 mRNA was induced by ethylene in ‘Kardinal’ than that of ‘Samantha’. As an ethylene action inhibitor, STS at concentration of 0.2 mmol/L generally inhib-ited the expression of Rh-ACSs and Rh-ACO in both cultivars, although it induced the expression of Rh-ACS3 transiently in ‘Kardinal’. Our results suggests that ‘Kardinal’ is more sensitive to ethylene than ‘Samantha’; and the changes of Rh-ACS3 expression caused by ethylene might be related to the acceleration of flower opening in ‘Samantha’ and the inhibition in ‘Kardinal’. Additional results indicated that three Rh-ACSs genes were differentially associated with flower opening and senescence as well as wounding.
基金This work was supported by the National Natural Science Foundation of China （31170222, 31470343, U 1201212）.
文摘Rapid and dynamic change in hydrogen peroxide （H2O2） levels can serve as an important signal to regulate various biological processes in plants. The change is realized by tilting the balance between its production and scavenging rates, in which membrane-associated NADPH oxidases are known to play a crucial role. Functioning independently from NADPH oxidases, glycolate oxidase （GLO） was recently demonstrated as an aitemative source for H2O2 production during both germ-for-germ and non-host resistance in plants. In this study, we show that GLO physically interacts with catalase （CAT） in rice leaves, and that the interaction can be deregulated by salicylic acid （SA）. Furthermore, the GLO-mediated H2O2 accumulation is synergistically enhanced by SA. Based on the well-known mechanism of substrate channeling in enzyme complexes, SA-induced H2O2 accumulation likely results from SA-induced GLO-CAT dissociation. In the GLO-CAT complex, GLO-mediated H2O2 production during photorespiration is very high, whereas the affinity of CAT for H2O2 （measured Km ≈ 43 raM） is extraordinarily low. This unique combination can further potentiate the increase in H2O2 when GLO is dissociated from CAT. Taken together, we propose that the physical association-dissociation of GLO and CAT, in response to environmental stress or stimuli, seems to serve as a specific mechanism to modulate H2O2 levels in rice.
文摘We analyzed 20 chemosensory protein （CSP） genes of the silkworm Bombyx mori. We found a high number of retrotransposons inserted in introns. We then analyzed expression of the 20 BrnorCSP genes across tissues using quantitative real-time polymerase chain reaction （PCR）. Relatively low expression levels of BmorCSPs were found in the gut and fat body tissues. We thus tested the effects of endectocyte insecticide abamectin （B 1 a and Blb avermectins） on BmorCSP gene expression. Quantitative real-time PCR experi- ments showed that a single brief exposure to insecticide abamectin increased dramatically CSP expression not only in the antennae but in most tissues, including gut and fat body. Furthermore, our study showed coordinate expression of CSPs and metabolic cytochrome P450 enzymes in a tissue-dependent manner in response to the insecticide. The function of CSPs remains unknown. Based on our results, we suggest a role in detecting xenobiotics that are then detoxified by cytochrome P450 anti-xenobiotic enzymes.
文摘Sex determination in plants gives rise to unisexual flowers that facilitate outcrossing and enhance genetic diversity. In cucumber and melon, ethylene promotes carpel development and arrests sta- men development. Five sex-determination genes have been identified, including four encoding 1-aminocyclopropane-l-carboxylate （ACC） synthase that catalyzes the rate-limiting step in ethylene biosynthesis, and a transcription factor gene CmWIP1 that corresponds to the Mendelian locus gynoecious in melon and is a negative regulator of femaleness. ACC oxidase （ACO） converts ACC into ethylene; how- ever, it remains elusive which ACO gene in the cucumber genome is critical for sex determination and how CmWIP1 represses development of female flowers. In this study, we discovered that mutation in an ACO gene, CsAC02, confers androecy in cucumber that bears only male flowers. The mutation disrupts the enzymatic activity of CsAC02, resulting in 50% less ethylene emission from shoot tips. CsAC02 was ex- pressed in the carpel primordia and its expression overlapped with that of CsACS11 in female flowers at key stages for sex determination, presumably providing sufficient ethylene required for proper CsACS2 expression. CmAC03, the ortholog of CsACO2, showed a similar expression pattern in the carpel region, suggesting a conserved function of CsACO2/CmACO3. We demonstrated that CsWlP1, the ortholog of CmWlP1, could directly bind the promoter of CsAC02 and repress its expression. Taken together, we propose a presumably conserved regulatory module consisting of WlP1 transcription factor and ACO controls unisexual flower development in cucumber and melon.
