Jadomycin is an antibiotic that has shown activities against bacteria, yeasts and fungi as well as cytotoxic properties to cancer cells. Because of the wide range of its inhibitory actions, jadomycin shows promise as ...Jadomycin is an antibiotic that has shown activities against bacteria, yeasts and fungi as well as cytotoxic properties to cancer cells. Because of the wide range of its inhibitory actions, jadomycin shows promise as a novel antibiotic and cancer treatment drug. Streptomyces venezuelae are aerobic bacteria that produce jadomycin and the size of bacterial population can significantly affect the yield of jadomycin. Therefore, the bacterial population must be accurately measured in order to standardize the reproducibility of jadomycin production process. In this study, a dehydrogenase activity measurement test, using triphenyl tetrazolium chloride (TTC), was used to measure the dehydrogenase activity of Streptomyces venezuelae during growth in maltose-yeast extract-malt extract (MYM) broth. The aims were to evaluate the effectiveness of the test for measuring microbial growth and to study the effects of the test conditions (incubation time, incubation temperature and medium pH) on triphenyl formazan (TF) yield. The results showed that the TF yield was highly correlated to the optical density. The highest TF yield was observed at a pH of 6 at all incubation times and temperature. Lower TF yields were obtained at higher temperature (40 and 50oC) compared to those obtained at lower temperatures (22 and 30oC). The difference between the yields obtained at 22oC and 30oC were not significant. The differences between incubation time were also not significant. The recommended test conditions are an incubation time of 1 hour at a temperature of 30oC and a pH of 6 followed by three extractions using methanol.展开更多
The corrosion inhibition of cold rolled steel(CRS) in 7.0 mol·L^(-1) H_2 SO_4 solution by red tetrazolium(RTZ) was carefully investigated using both experimental procedures and theoretical techniques. The results...The corrosion inhibition of cold rolled steel(CRS) in 7.0 mol·L^(-1) H_2 SO_4 solution by red tetrazolium(RTZ) was carefully investigated using both experimental procedures and theoretical techniques. The results show that RTZ acts as an effective inhibitor for the corrosion of CRS in 7.0 mol·L^(-1) H_2SO_4, and the maximum inhibition efficiency is higher than 95% with a RTZ concentration of 2.0 mmol·L^(-1). The adsorption of RTZ on CRS surface follows Langmuir isotherm. RTZ effectively retards both cathodic and anodic reactions, and acts as a mixed-type inhibitor. EIS exhibits two capacitive loops, and their resistances increase drastically in the presence of RTZ. SEM and AFM confirm that the addition of RTZ could significantly retard the corrosion of CRS surface. A series of characterizations like FTIR, RS, XRD and XPS reveal that the corrosion CRS surface is composed of the corrosion products of iron sulfates, iron oxides and iron hydroxide, as well as inhibitor. Theoretical results of quantum chemical calculation and molecular dynamics(MD) indicate that the adsorption center of RTZ+(organic cationic part of RTZ) mainly relies on its tetrazole ring,and the adsorption of RTZ+on Fe(001) surface is in a nearly flat orientation mode.展开更多
4-Hydroxyphenylpyruvate dioxygenase(EC 1.13.11.27,HPPD)is currently one of the popular targets of herbicide research,and herbicides targeting it have shown promising results in treating resistant weeds.However,the lon...4-Hydroxyphenylpyruvate dioxygenase(EC 1.13.11.27,HPPD)is currently one of the popular targets of herbicide research,and herbicides targeting it have shown promising results in treating resistant weeds.However,the longterm application of HPPD inhibitors with in their classical scaffolds inevitably leads to the development of drug resistance.To further delay the underlying development of weed resistance to HPPD inhibitors,we successfully screened HPPD inhibitor pharmacophore with novel chelate structures using computer-aided drug molecular design and obtained 2-trifluoromethyltetrazolium nicotinamide derivatives through active fragment splicing.Among these derivatives,6-(3,3-diethyl-1-methylureido)-N-(1-methyl-1H-tetrazol-5-yl)-2-(trifluoromethyl)nicotinamide(compound 31),exhibited the most promising in vitro enzyme inhibitory activity,with IC_(50) value of 0.072μM,which was approximately five times better than that of the control agent mesotrione(IC_(50)?0.363μM).The crystal structure of the AtHPPD complexed with compound 31(2.0Å)and the binding energy calculations of the representative compounds revealed several important interactions of the ligand binding to the target protein,which explained the superior enzyme inhibitory activity of the compounds at the molecular level.In addition,compounds 7 and 31 possessed 100%inhibition against the five target weeds at the tested dosage and both were more effective against Setaria viridis than mesotrione.In general,it is promising to design novel HPPD inhibitors by developing novel chelating structures,and compounds 7 or 31 could be used as the leads for further development of valuable HPPD inhibitors.展开更多
A new complex has been synthesized by the reaction of CuBr and 1,4-bis（2-allyl-2 H-tetrazol-5-yl）benzene. The crystal structure of the resulting complex, [Cu3（1,4-bis（2-allyl-2 H-tetrazol-5-yl）benzene）Br3]n（1）...A new complex has been synthesized by the reaction of CuBr and 1,4-bis（2-allyl-2 H-tetrazol-5-yl）benzene. The crystal structure of the resulting complex, [Cu3（1,4-bis（2-allyl-2 H-tetrazol-5-yl）benzene）Br3]n（1）, has been determined by single-crystal X-ray diffraction analysis. Complex 1 is of monoclinic system, space group P21/c with a = 10.983（7）, b = 6.294（4）, c = 17.606（10） ?, β = 102.465（6）°, V = 1188.4（3） ?3 and Mr = 577.52. Structural analyses revealed complex 1 shows a three-dimensional（3 D） framework. The thermal stability and luminescent properties of the complex are also investigated.展开更多
A series of new complex salts of the type [R]2[MC14] where R =[Ph-C=n-N-Ph N=N-Ph],M = Mn2＋, Co2＋, Ni2＋, Cu2＋ and Zn2＋ wereprepared and characterized by elemental analysis, molar conductance, IR and UVNis is spec...A series of new complex salts of the type [R]2[MC14] where R =[Ph-C=n-N-Ph N=N-Ph],M = Mn2＋, Co2＋, Ni2＋, Cu2＋ and Zn2＋ wereprepared and characterized by elemental analysis, molar conductance, IR and UVNis is spectral studies and magnetic measurements.The crystal structure of[Ph-C=n-N-Ph N=N-Ph]2[CuCl4] was determined by single crystal X-ray crystallography. The structure consisted of anion part and a 2,3,5-（triphenyl） tetrazolium cation as counter ions. The copper complex has a distorted tetrahedral geometry, the CI（1）-Cu-CI（2） [124.33 （2°）] and Cl（3）-Cu-Cl（4） [131.03 （2°）] angles are significantly larger than the ideal tetrahedral. The [CuCI4] anion and its counter ions are connected through a hydrogen bonds between C1 of the dianion and hetero aromatic rings by Cl-π, π-π and C-H … π, interactions.展开更多
The purpose of this study was to verify the efficiency of methods of pre-conditioning and concentrations of tetrazolium solution in the evaluation of physiological quality of Stizolobium aterrimum seeds. Commercial se...The purpose of this study was to verify the efficiency of methods of pre-conditioning and concentrations of tetrazolium solution in the evaluation of physiological quality of Stizolobium aterrimum seeds. Commercial seeds have passed through the process of accelerated aging for composing lots of 0, 24, 48, 96 and 144 hours, and were submitted to the pre-conditioning: 1) Scarification with sandpaper number 100 and immersion in water at room temperature for 18 hours, 2) Immersion in water at 95°C and maintained in the same water outside the heating at 25°C for 18 hours. After preconditioning, the seed coats were removed and immersed in embryos tetrazolium salt at 0.25%, 0.5% and 1% for 150 minutes and maintained in the dark at 25°C for color development. To compare the results obtained in the tetrazolium test, we performed germination test, first counting and germination speed index. The method of scarification with sandpaper and later soaked in water for 18 hours at 25°C, the most efficient way in preconditioning of seeds of Stizolobium aterrimum and concentration of 1.0% tetrazolium solution for 150 minutes at 25°C, allows evaluating the quality of seed lots from this species.展开更多
The tetrazolium salt 2-（4-Iodophenyl） -3-（ 4-nitrophenyl ） -5-phenyltetrazolium chloride （INT） was used as a tool fi）r estimating the activity of the electron transport system （ETS） in activated sludge in a 4...The tetrazolium salt 2-（4-Iodophenyl） -3-（ 4-nitrophenyl ） -5-phenyltetrazolium chloride （INT） was used as a tool fi）r estimating the activity of the electron transport system （ETS） in activated sludge in a 40 L sequencing batch reactor （SBR） and domestie sewage as the organic substrate. The activity of INT-ETS during one SBR cycle, and the effeet of the ammonia concentration and the concentration of organic matter influent on the INT-ETS activity were investigated. The results show that： the use of INT is reliable in estimating of biological activity of activated sludge of SBR system; Biological activity of organic matter biodegradation, nitrification and denitrification process in SBR system reduce orderly. Obviously, INT-ETS activity reduces from 232.59 rny/（g · h） to 190. 65 rag/（ g ·h） at first and then decreases to 113.88 my/（ g · h） when influent concentration of COD and NH4＋-N is 300 my/L and 40 mg/L respectively. In addition, various influent Nitrogen （NH4＋-N are 14.5 mg/L and 42.0 my/L） and organic shock loading （COD are 293 mg/L and 685 my/L） experimenntions cure prove that operational conditions have no obvious effect on INT-ETS variation rule. However, the time of the appearance of feature points marking different reaction phase is influenced.展开更多
文摘Jadomycin is an antibiotic that has shown activities against bacteria, yeasts and fungi as well as cytotoxic properties to cancer cells. Because of the wide range of its inhibitory actions, jadomycin shows promise as a novel antibiotic and cancer treatment drug. Streptomyces venezuelae are aerobic bacteria that produce jadomycin and the size of bacterial population can significantly affect the yield of jadomycin. Therefore, the bacterial population must be accurately measured in order to standardize the reproducibility of jadomycin production process. In this study, a dehydrogenase activity measurement test, using triphenyl tetrazolium chloride (TTC), was used to measure the dehydrogenase activity of Streptomyces venezuelae during growth in maltose-yeast extract-malt extract (MYM) broth. The aims were to evaluate the effectiveness of the test for measuring microbial growth and to study the effects of the test conditions (incubation time, incubation temperature and medium pH) on triphenyl formazan (TF) yield. The results showed that the TF yield was highly correlated to the optical density. The highest TF yield was observed at a pH of 6 at all incubation times and temperature. Lower TF yields were obtained at higher temperature (40 and 50oC) compared to those obtained at lower temperatures (22 and 30oC). The difference between the yields obtained at 22oC and 30oC were not significant. The differences between incubation time were also not significant. The recommended test conditions are an incubation time of 1 hour at a temperature of 30oC and a pH of 6 followed by three extractions using methanol.
基金Supported by the National Natural Science Foundation of China(51361027)the Training Program of Young and Middle Aged Academic and Technological Leaders in Yunnan Province(2015HB049)
文摘The corrosion inhibition of cold rolled steel(CRS) in 7.0 mol·L^(-1) H_2 SO_4 solution by red tetrazolium(RTZ) was carefully investigated using both experimental procedures and theoretical techniques. The results show that RTZ acts as an effective inhibitor for the corrosion of CRS in 7.0 mol·L^(-1) H_2SO_4, and the maximum inhibition efficiency is higher than 95% with a RTZ concentration of 2.0 mmol·L^(-1). The adsorption of RTZ on CRS surface follows Langmuir isotherm. RTZ effectively retards both cathodic and anodic reactions, and acts as a mixed-type inhibitor. EIS exhibits two capacitive loops, and their resistances increase drastically in the presence of RTZ. SEM and AFM confirm that the addition of RTZ could significantly retard the corrosion of CRS surface. A series of characterizations like FTIR, RS, XRD and XPS reveal that the corrosion CRS surface is composed of the corrosion products of iron sulfates, iron oxides and iron hydroxide, as well as inhibitor. Theoretical results of quantum chemical calculation and molecular dynamics(MD) indicate that the adsorption center of RTZ+(organic cationic part of RTZ) mainly relies on its tetrazole ring,and the adsorption of RTZ+on Fe(001) surface is in a nearly flat orientation mode.
基金the National Key Research and Development Program of China(No.2021YFD1700100)National Natural Science Foundation of China(No.22007035,21837001)+1 种基金Knowledge Innovation Program of Wuhan-Basic Research(No.2022013301015174)the Key Research and Development Program of Hubei Province(2022BBA001).
文摘4-Hydroxyphenylpyruvate dioxygenase(EC 1.13.11.27,HPPD)is currently one of the popular targets of herbicide research,and herbicides targeting it have shown promising results in treating resistant weeds.However,the longterm application of HPPD inhibitors with in their classical scaffolds inevitably leads to the development of drug resistance.To further delay the underlying development of weed resistance to HPPD inhibitors,we successfully screened HPPD inhibitor pharmacophore with novel chelate structures using computer-aided drug molecular design and obtained 2-trifluoromethyltetrazolium nicotinamide derivatives through active fragment splicing.Among these derivatives,6-(3,3-diethyl-1-methylureido)-N-(1-methyl-1H-tetrazol-5-yl)-2-(trifluoromethyl)nicotinamide(compound 31),exhibited the most promising in vitro enzyme inhibitory activity,with IC_(50) value of 0.072μM,which was approximately five times better than that of the control agent mesotrione(IC_(50)?0.363μM).The crystal structure of the AtHPPD complexed with compound 31(2.0Å)and the binding energy calculations of the representative compounds revealed several important interactions of the ligand binding to the target protein,which explained the superior enzyme inhibitory activity of the compounds at the molecular level.In addition,compounds 7 and 31 possessed 100%inhibition against the five target weeds at the tested dosage and both were more effective against Setaria viridis than mesotrione.In general,it is promising to design novel HPPD inhibitors by developing novel chelating structures,and compounds 7 or 31 could be used as the leads for further development of valuable HPPD inhibitors.
文摘A new complex has been synthesized by the reaction of CuBr and 1,4-bis（2-allyl-2 H-tetrazol-5-yl）benzene. The crystal structure of the resulting complex, [Cu3（1,4-bis（2-allyl-2 H-tetrazol-5-yl）benzene）Br3]n（1）, has been determined by single-crystal X-ray diffraction analysis. Complex 1 is of monoclinic system, space group P21/c with a = 10.983（7）, b = 6.294（4）, c = 17.606（10） ?, β = 102.465（6）°, V = 1188.4（3） ?3 and Mr = 577.52. Structural analyses revealed complex 1 shows a three-dimensional（3 D） framework. The thermal stability and luminescent properties of the complex are also investigated.
文摘A series of new complex salts of the type [R]2[MC14] where R =[Ph-C=n-N-Ph N=N-Ph],M = Mn2＋, Co2＋, Ni2＋, Cu2＋ and Zn2＋ wereprepared and characterized by elemental analysis, molar conductance, IR and UVNis is spectral studies and magnetic measurements.The crystal structure of[Ph-C=n-N-Ph N=N-Ph]2[CuCl4] was determined by single crystal X-ray crystallography. The structure consisted of anion part and a 2,3,5-（triphenyl） tetrazolium cation as counter ions. The copper complex has a distorted tetrahedral geometry, the CI（1）-Cu-CI（2） [124.33 （2°）] and Cl（3）-Cu-Cl（4） [131.03 （2°）] angles are significantly larger than the ideal tetrahedral. The [CuCI4] anion and its counter ions are connected through a hydrogen bonds between C1 of the dianion and hetero aromatic rings by Cl-π, π-π and C-H … π, interactions.
文摘The purpose of this study was to verify the efficiency of methods of pre-conditioning and concentrations of tetrazolium solution in the evaluation of physiological quality of Stizolobium aterrimum seeds. Commercial seeds have passed through the process of accelerated aging for composing lots of 0, 24, 48, 96 and 144 hours, and were submitted to the pre-conditioning: 1) Scarification with sandpaper number 100 and immersion in water at room temperature for 18 hours, 2) Immersion in water at 95°C and maintained in the same water outside the heating at 25°C for 18 hours. After preconditioning, the seed coats were removed and immersed in embryos tetrazolium salt at 0.25%, 0.5% and 1% for 150 minutes and maintained in the dark at 25°C for color development. To compare the results obtained in the tetrazolium test, we performed germination test, first counting and germination speed index. The method of scarification with sandpaper and later soaked in water for 18 hours at 25°C, the most efficient way in preconditioning of seeds of Stizolobium aterrimum and concentration of 1.0% tetrazolium solution for 150 minutes at 25°C, allows evaluating the quality of seed lots from this species.
基金Sponsored by the National Water Pollution Control and Management Technology Major Projects(Grant No.2012ZX07408001-07,2012ZX07201001-01)
文摘The tetrazolium salt 2-（4-Iodophenyl） -3-（ 4-nitrophenyl ） -5-phenyltetrazolium chloride （INT） was used as a tool fi）r estimating the activity of the electron transport system （ETS） in activated sludge in a 40 L sequencing batch reactor （SBR） and domestie sewage as the organic substrate. The activity of INT-ETS during one SBR cycle, and the effeet of the ammonia concentration and the concentration of organic matter influent on the INT-ETS activity were investigated. The results show that： the use of INT is reliable in estimating of biological activity of activated sludge of SBR system; Biological activity of organic matter biodegradation, nitrification and denitrification process in SBR system reduce orderly. Obviously, INT-ETS activity reduces from 232.59 rny/（g · h） to 190. 65 rag/（ g ·h） at first and then decreases to 113.88 my/（ g · h） when influent concentration of COD and NH4＋-N is 300 my/L and 40 mg/L respectively. In addition, various influent Nitrogen （NH4＋-N are 14.5 mg/L and 42.0 my/L） and organic shock loading （COD are 293 mg/L and 685 my/L） experimenntions cure prove that operational conditions have no obvious effect on INT-ETS variation rule. However, the time of the appearance of feature points marking different reaction phase is influenced.
