[Objective] The paper was to study the antagonistic effect of Russula virescens （Schaeff.） Ft. against Bortrytis cinerea. [Method] Using the confrontation culture method, the antagonistic effect of mycelium, ferment...[Objective] The paper was to study the antagonistic effect of Russula virescens （Schaeff.） Ft. against Bortrytis cinerea. [Method] Using the confrontation culture method, the antagonistic effect of mycelium, fermentation broth and mycelial extract of R. virescens against B. cinerea was studied. [Result] The antagonistic ef- fect of R. vivesscens against B. cinerea was mainly manifested as hyperparasitism of mycelium and inhibition effect of metabolites. The inhibition rate of confrontation growth was between 46.9% and 52.3%, and hyperparasitism phenomenon was obvi- ous. The fermentation broth of R. virescens cultured by PDB medium had the strongest growth inhibition effect, and the growth inhibition rate against B. cinerea was the highest of 61.59%. The thermal stability of fermentation broth was good, the mycelial extract of R. virescens had no inhibition effect against the growth of B. cinerea. [Conclusion] The study provided theoretical basis for subsequent differentiation and drug sensitivity of B. cinerea.展开更多
Objective: To investigate the effects of Andrographis paniculata(Burm.f.) Wall. Ex Nees(A. paniculata) on expressions and activities of catalase, superoxide dismutase and alkylhydroperoxide reductase C in Staphylococc...Objective: To investigate the effects of Andrographis paniculata(Burm.f.) Wall. Ex Nees(A. paniculata) on expressions and activities of catalase, superoxide dismutase and alkylhydroperoxide reductase C in Staphylococcus aureus(S. aureus) with respect to its survival in vitro. Methods: Antioxidative property of methanolic leaves extract of A. paniculata(0.06 mg/m L). Minimum inhibitory concentration(MIC) was determined by its ability to reduce hydrogen peroxide(H_2O_2) toxicity against S. aureus ATCC 25923(3.8×10~8 cfu/m L). Effects of the extract on expressions of kat A(encoding catalase), sod A and sod M [encoding superoxide dismutases(SODs)], and ahp C [encoding alkylhydroperoxide reductase C(AhpC)] in S. aureuswere determined by RT-q PCR and corresponding enzyme activity assays were performed. Nitroblue tetrazolium reduction(NBT) assay was performed to determine effects of the extract on intracellular and extracellular levels of O_2-in S. aureus. Results: Cells challenged with 7.5 mmol/L H_2O_2 showed 0% survival in 30 min whereas 25% survived after treatment with the extract and H_2O_2. Cells that were treated with the extract alone had 43% survival in the same exposure period. Expressions of sod A and sod M genes in extract-treated cells were lowered 0.8-fold and 0.7-fold, respectively with decrease in total SOD activity of 26.8 U compared to untreated cells, 32.4 U(P<0.05). In contrast, extract-treated S. aureus cells showed 3.3-fold increase in kat A expression with corresponding increase in catalase activity of 1.828 U compared to untreated cells which was 1.248 U,(P<0.05). More profoundly, ahp C expression was increased 61-fold in extract-treated cells,(P<0.05) with corresponding increase in Ahp C activity of 0.018 U compared to untreated cells, 0.012U,(P<0.05). Extract-treated cells had significantly lower intra-and extracellular O_2-levels with absorbance readings(A_(575nm)) of 0.340 and 0.524 compared to untreated cells which were 0.516 and 0.928(P<0.05), respectively. Conclusions: Taken together these results suggest that the low MIC of A. paniculatamethanolic leaves extract(0.06 mg/m L) reduce H_2O_2 toxicity and more importantly, was in itself effectively inhibitory against S. aureus. Further, our observations suggest that a probable mode of its inhibitory mechanism against S. aureus is by reducing total SOD activity through downregulation of sod A and sod M expressions.展开更多
Aflatoxin is a strong carcinogenic and toxic fungal toxin produced by Aspergillus flavus and other Aspergillus species,and can seriously threaten the health of consumers,thus becoming a global concern.Corn,as an impor...Aflatoxin is a strong carcinogenic and toxic fungal toxin produced by Aspergillus flavus and other Aspergillus species,and can seriously threaten the health of consumers,thus becoming a global concern.Corn,as an important oil and economic crop,is highly susceptible contaminated by aflatoxin.In this study,antagonistic bacteria with strong inhibitory effect on aflatoxin were screened to provide support for the treatment aflatoxin contamination control in corn.Ten strains which have strong antagonistic effects against A.flavus were isolated from healthy corn from different corn producing areas in China.Among them,the antagonistic bacteria JTFM1001 through corn kernels in vivo and field experiment,the inhibition effect of aflatoxin contamination reached above 70%and 55%,respectively.And the strain was identified as Bacillus subtilis based on its morphological,physiological and biochemical characteristics and phylogenetic analysis of 16S rDNA.In addition,our data showed that it can colonize in the rhizosphere and survive for a long time,forming the dominant flora,with broad application prospect.Finally,we were surprised to find that the antibacterial metabolites secreted by the antagonistic bacteria was one of the mechanisms of its inhibition of A.flavus and aflatoxin.This will provide us with new ideas and perspectives on the effective prevention and control of aflatoxin contamination in corn and corn oil.展开更多
Protective effects of calcium antagonists, chlorpromazine (CPZ) and nimodepine (NI-MO), on cadmium-induced toxicity were investigated. After giving CdCl2 (0. 44mg Cd/kg,ip), CPZ (5mg/kg, ip) or NIMO (8mg/kg, po) were ...Protective effects of calcium antagonists, chlorpromazine (CPZ) and nimodepine (NI-MO), on cadmium-induced toxicity were investigated. After giving CdCl2 (0. 44mg Cd/kg,ip), CPZ (5mg/kg, ip) or NIMO (8mg/kg, po) were administered every day to Sprague-Dawley (S. D. ) rats for a week. Then, urinary N- acetyl-β-D- glucosaminidase (NAG ), uri -nary cadmium and bloocl cadmium were measured. The accumulation of cadmium in the kid-ney cortex, content of renal calmodulin, hemoglobin and the ultrastructural damage of proxi-mal convoluted tubules of rats were examined three weeks after the last administration. Re-sults indicated that the calcium antagonists partly protected against toxic effects induced bycadmium in different manners. These data provide further evidence for the new hypothesisthat the cross effect of cadmium and calcium in calmodulin regulated systems may be responsi-ble for the mechanism of cadmium intoxication. 'The results suggested that the calcium antag-onists could be a new and promising approach in the therapy of heavy metaLinduced diseases展开更多
[ Objective ] The paper was to study the growth-promoting and antagonistic action of endophytic bacteria strains Itb57 and Itb295 of tobacco to explore their functions in biological control. [ Method] The growth-promo...[ Objective ] The paper was to study the growth-promoting and antagonistic action of endophytic bacteria strains Itb57 and Itb295 of tobacco to explore their functions in biological control. [ Method] The growth-promoting effects of bacterial suspension ~ff endophytic bacteria Itb57 and Itb295 on tobacco seedling un- der different treatment modes were studied using potting method in greenhouse. The antagonistic action of bacterial suspension of endophytic bacteria Itb57 and Itb295 on Phytophthora nicotianae, Alternaria alternata and Botrytis cinerea were measured by duel culture method. [ Result] Bacterial suspensions of enduphytic bacteria Itb57 and Itb295 had certain growth-promoting effects on tobacco seedling, which could significantly increase the fresh weight and dry weight in aerial part; the growth-promoting effect of soaking ＋ spraying and irrigating treatment was the best. Itb57 strain had good antagonistic action against P. nicotianae. A. alterna- ta and B. cinerea, while Itb295 strain only had good antifungal effect against P. nicotianae. [ Conclusion] The results provided basis for the study and application of tobacco endophytic bacteria strains Itb57 and Itb295 in biocontrol of tobacco diseases.展开更多
The mutagemc effects of microwave and chromium trioxide （CrO3） on Vicia faba root tip were studied. Micronucleus assay and chromosomal aberration assay were used to determine the mitotic index, the micronucleus freq...The mutagemc effects of microwave and chromium trioxide （CrO3） on Vicia faba root tip were studied. Micronucleus assay and chromosomal aberration assay were used to determine the mitotic index, the micronucleus frequency and chromosomal aberration frequency of Vicia faba root tip cells induced by microwave and CrO3. The results showed that the micronucleus frequency decreased, and that the mitotic index and chromosomal aberration frequency showed linear dose responses to CrO3, in treatment of microwave for 5 s. In microwave of 25 s, the mitotic index decreased, the micronucleus frequency and chromosomal aberration frequency increased with increase of CrO3 concentration. We concluded that microwave and CrO3 had antagonistic effect on the mitotic index of Vicia faba root tip cells, but had synergetic effect on micronucleus frequency and chromosomal aberration frequency of Viciafaba root tip cells.展开更多
[Objectives] This study was conducted to obtain actinomycetes strains having antagonistic effect on Ustilago scitaminea Syd.[Methods] At first, actinomycetes strains were isolated from 22 soil samples in Hainan sugarc...[Objectives] This study was conducted to obtain actinomycetes strains having antagonistic effect on Ustilago scitaminea Syd.[Methods] At first, actinomycetes strains were isolated from 22 soil samples in Hainan sugarcane regions. Then, antagonistic actinomycetes against U. scitaminea were screened by confrontation culture. Finally, the taxonomic status of antagonistic actinomycetes was determined using 16S rDNA.[Results] From the 22 samples, 984 actinomycetes strains were isolated. From all the isolated strains, 23 antagonistic actinomycetes strains were obtained through primary screening, and one strains with better antagonistic effect was then obtained through secondary screening, and designated FAS. 16S rDNA identification showed that strain FAS shared 99% sequence similarity with Streptomyces cealestis US24. A phylogenetic tree was built with MAGE 7.0 software, and the results showed that strain FAS had the shortest genetic distance with S. caelestis US24. Therefore, the actinomycetes FAS was determined as S. caelestis .[Conclusions] This study provides a new biocontrol method for the biological control of sugarcane smut, thereby ensuring sustainable development of sugarcane industry and sugar industry.展开更多
Selenium(Se)in paddy rice is one of the significant sources of human Se nutrition.However,the effect of arsenic(As)pollution in soil on the translocation of Se species in rice plants is unclear.In this research,a pot ...Selenium(Se)in paddy rice is one of the significant sources of human Se nutrition.However,the effect of arsenic(As)pollution in soil on the translocation of Se species in rice plants is unclear.In this research,a pot experiment was designed to examine the effect of the addition of 50 mg As/kg soil as arsenite or arsenate on the migration of Se species from soil to indica Minghui 63 and Luyoumingzhan.The results showed that the antagonism between inorganic As and Se was closely related to the rice cultivar and Se oxidation state in soil.Relative to the standalone selenate treatment,arsenite significantly(p<0.05)decreased the accumulation of selenocystine,selenomethionine and selenate in the roots,stems,sheaths,leaves,brans and kernels of both cultivars by 21.4%-100.0%,40.0%-100.0%,41.0%-100%,5.4%-96.3%,11.3%-100.0% and 26.2%-39.7% respectively,except for selenocystine in the kernels of indica Minghui 63 and selenomethionine in the leaves of indica Minghui 63 and the stems of indica Luyoumingzhan.Arsenate also decreased(p<0.05)the accumulation of selenocystine,selenomethionine and selenate in the roots,stems,brans and kernels of both cultivars by 34.9%-100.0%,30.2%-100.0%,11.3%-100.0% and 5.6%-39.6%respectively,except for selenate in the stems of indica Minghui 63.However,relative to the standalone selenite treatment,arsenite and arsenate decreased(p<0.05)the accumulation of selenocystine,selenomethionine and selenite only in the roots of indica Minghui 63 by 45.5%-100.0%.Our results suggested that arsenite and arsenate had better antagonism toward Se species in selenate-added soil than that in selenite-added soil;moreover,arsenite had a higher inhibiting effect on the accumulation of Se species than arsenate.展开更多
Inhibitive properties of NAC and NAM as well as their mixture have been investigated in two different corrosive media through potentiodynamic polarization and electrochemical impedance spectroscopy at 298 K. These ele...Inhibitive properties of NAC and NAM as well as their mixture have been investigated in two different corrosive media through potentiodynamic polarization and electrochemical impedance spectroscopy at 298 K. These electrochemical measurements indicate that the inhibition efficiency increases with the concentration for each of the inhibitors used separately as well as for their mixture. In both cases, the combination behaves as mixed type inhibitor with a great cathodic tendency. NaCl 3.5% highlights an antagonist effect of NAM which reduces the effectiveness of NAC whereas HNO3 1M shows a synergistic effect between them.展开更多
Oxidation stability of lubricating oil is critical for the smooth operation of industrial equipment such as turbines.Sludge formation is a major issue in turbine operation.Currently,the turbine oil industry employs an...Oxidation stability of lubricating oil is critical for the smooth operation of industrial equipment such as turbines.Sludge formation is a major issue in turbine operation.Currently,the turbine oil industry employs antioxidants,especially,the combination of aminic and phenolic antioxidants,as the key additives to reduce sludge formation.Aromatic amines,primarily PANA,are considered as the most effective antioxidants in terms of oxidation induction time(OIT)measured by the RPVOT test.However,PANA is also a sludge former.Phenolic antioxidants are normally used in combination with the aminic antioxidants.It is widely believed that there exists a synergistic effect between the phenolic and aminic antioxidants.Regarding the interaction mechanism between the two types of antioxidants,it is generally accepted that phenolics act as a hydrogen donor to help regenerate the consumed aminic antioxidants.This mechanism can only explain some of the phenomena observed in field practice,but there are many other questions remaining unanswered including the antagonistic effect between PANA and phenolics.In this study,we used HPLC,FTIR and LC-MS to monitor the degradation products of the oil systems that were formulated with various aminic and phenolic antioxidants.For the APANA alone system,we identified the formation of dimers and trimers of APANA.For the PANA alone system,we identified the formation of dimers and tetramers.The dimers,trimers,and tetramers of PANA have very limited solubility.These findings therefore help explain why PANA is a sludge former.The oligomerizations(dimerization,trimerization,etc.)regenerate the N-H functionality,thus explaining why the PANA as well as other amines are very effective antioxidants.For the PANA/phenolic system,the oligomers of PANA were greatly reduced.Instead,we identified species that were formed by the recombination of the PANA radicals,or the PANA oligomeric radicals with the phenolic radicals.This,to our knowledge,has not been reported so far.The recombination of aminyl radicals and the phenolic radicals decreases the capability of regenerating the N-H functionality,which helps explain the antagonistic effect observed in the PANA/phenolic system.It also suggests that the phenolic antioxidants are very important in suppressing the sludge formation in the turbine oil system because the recombination products of PANA and phenolics have much better solubility than the PANA oligomers.展开更多
DFT quantum chemical computations have been carried out at the B3LYP/6-31G (d) level. Full geometry optimization has been performed and equilibrium geometries for a new series of phenyl thiazoles have been located. Gr...DFT quantum chemical computations have been carried out at the B3LYP/6-31G (d) level. Full geometry optimization has been performed and equilibrium geometries for a new series of phenyl thiazoles have been located. Ground state electronic properties, charge density distributions, dipole moments and its components have been calculated and reported. Effect of substituents on the geometry and on the polarization of the studied series of compounds are analyzed and discussed. Some structural features have been pinpointed to underline the affinity and selectivity of the studied compounds as adenosine A3-receptor antagonists. Results of the present work indicate that activity towards A3 receptor sites is directly correlated with both of the polarity and the co-planarity of the thiazole.展开更多
AIM: To study the effects of aminoguanidine (AG) and two L-arginine analogues N(omega)-nitro-L-arginine methyl ester (L-NAME) and N(omega)-nitro-L-arginine (L-NNA) on nitric oxide (NO) production induced by cytokines ...AIM: To study the effects of aminoguanidine (AG) and two L-arginine analogues N(omega)-nitro-L-arginine methyl ester (L-NAME) and N(omega)-nitro-L-arginine (L-NNA) on nitric oxide (NO) production induced by cytokines (TNF-alpha, IL-1 beta, and IFN-gamma) and bacterial lipopolysaccharide (LPS) mixture (CM) in the cultured rat hepatocytes, and examine their mechanisms action. METHODS: Rat hepatocytes were incubated with AG, L-NAME, L-NNA, Actinomycin D (ActD) and dexamethasone in a medium containing CM (LPS plus TNF-alpha, IL-1 beta, and IFN-gamma) for 24h. NO production in the cultured supernatant was measured with the Griess reaction. Intracellular cGMP level was detected with radioimmunoassy. RESULTS: NO production was markedly blocked by AG and L-NAME in a dose-dependent manner under inflammatory stimuli condition triggered by CM in vitro. The rate of the maximum inhibitory effects of L-NAME (38.9%) was less potent than that obtained with AG(53.7%, P 【 0.05). There was no significant difference between the inhibitory effects of AG and two L-arginine analogues on intracellular cGMP accumulation in rat cultured hepatocytes. Non-specific NOS expression inhibitor dexamethasone (DEX)and iNOS mRNA transcriptional inhibitor ActD also significantly inhibited CM-induced NO production. AG(0.1 mmol x L(-1)) and ActD (0.2 ng x L(-1)) were equipotent in decreasing NO production induced by inflammatory stimuli in vitro, and both effects were more potent than that induced by non-selectivity NOS activity inhibitor L-NAME (0.1 mmol x L(-1)) under similar stimuli conditions (P【0.01). CONCLUSION: AG is a potent selective inhibitor of inducible isoform of NOS,and the mechanism of action may be not only competitive inhibition in the substrate level, but also the gene expression level in rat hepatocytes.展开更多
基金Supported by Applied Foundation Project of Science and Technology Department of Sichuan Province (2008JY0021-2)~~
文摘[Objective] The paper was to study the antagonistic effect of Russula virescens （Schaeff.） Ft. against Bortrytis cinerea. [Method] Using the confrontation culture method, the antagonistic effect of mycelium, fermentation broth and mycelial extract of R. virescens against B. cinerea was studied. [Result] The antagonistic ef- fect of R. vivesscens against B. cinerea was mainly manifested as hyperparasitism of mycelium and inhibition effect of metabolites. The inhibition rate of confrontation growth was between 46.9% and 52.3%, and hyperparasitism phenomenon was obvi- ous. The fermentation broth of R. virescens cultured by PDB medium had the strongest growth inhibition effect, and the growth inhibition rate against B. cinerea was the highest of 61.59%. The thermal stability of fermentation broth was good, the mycelial extract of R. virescens had no inhibition effect against the growth of B. cinerea. [Conclusion] The study provided theoretical basis for subsequent differentiation and drug sensitivity of B. cinerea.
基金supported by the Faculty of Health Sciences,Universiti Teknologi MARA,Puncak Alam Campus,Selangor and LESTARI grant(600-IRMI/MYRA 5/3/LESTARI(16/2016)
文摘Objective: To investigate the effects of Andrographis paniculata(Burm.f.) Wall. Ex Nees(A. paniculata) on expressions and activities of catalase, superoxide dismutase and alkylhydroperoxide reductase C in Staphylococcus aureus(S. aureus) with respect to its survival in vitro. Methods: Antioxidative property of methanolic leaves extract of A. paniculata(0.06 mg/m L). Minimum inhibitory concentration(MIC) was determined by its ability to reduce hydrogen peroxide(H_2O_2) toxicity against S. aureus ATCC 25923(3.8×10~8 cfu/m L). Effects of the extract on expressions of kat A(encoding catalase), sod A and sod M [encoding superoxide dismutases(SODs)], and ahp C [encoding alkylhydroperoxide reductase C(AhpC)] in S. aureuswere determined by RT-q PCR and corresponding enzyme activity assays were performed. Nitroblue tetrazolium reduction(NBT) assay was performed to determine effects of the extract on intracellular and extracellular levels of O_2-in S. aureus. Results: Cells challenged with 7.5 mmol/L H_2O_2 showed 0% survival in 30 min whereas 25% survived after treatment with the extract and H_2O_2. Cells that were treated with the extract alone had 43% survival in the same exposure period. Expressions of sod A and sod M genes in extract-treated cells were lowered 0.8-fold and 0.7-fold, respectively with decrease in total SOD activity of 26.8 U compared to untreated cells, 32.4 U(P<0.05). In contrast, extract-treated S. aureus cells showed 3.3-fold increase in kat A expression with corresponding increase in catalase activity of 1.828 U compared to untreated cells which was 1.248 U,(P<0.05). More profoundly, ahp C expression was increased 61-fold in extract-treated cells,(P<0.05) with corresponding increase in Ahp C activity of 0.018 U compared to untreated cells, 0.012U,(P<0.05). Extract-treated cells had significantly lower intra-and extracellular O_2-levels with absorbance readings(A_(575nm)) of 0.340 and 0.524 compared to untreated cells which were 0.516 and 0.928(P<0.05), respectively. Conclusions: Taken together these results suggest that the low MIC of A. paniculatamethanolic leaves extract(0.06 mg/m L) reduce H_2O_2 toxicity and more importantly, was in itself effectively inhibitory against S. aureus. Further, our observations suggest that a probable mode of its inhibitory mechanism against S. aureus is by reducing total SOD activity through downregulation of sod A and sod M expressions.
基金supported by the 2020-Innovation Project-Yi An,and Applied basic research plan of Hebei province-key basic research projects(17967502D).
文摘Aflatoxin is a strong carcinogenic and toxic fungal toxin produced by Aspergillus flavus and other Aspergillus species,and can seriously threaten the health of consumers,thus becoming a global concern.Corn,as an important oil and economic crop,is highly susceptible contaminated by aflatoxin.In this study,antagonistic bacteria with strong inhibitory effect on aflatoxin were screened to provide support for the treatment aflatoxin contamination control in corn.Ten strains which have strong antagonistic effects against A.flavus were isolated from healthy corn from different corn producing areas in China.Among them,the antagonistic bacteria JTFM1001 through corn kernels in vivo and field experiment,the inhibition effect of aflatoxin contamination reached above 70%and 55%,respectively.And the strain was identified as Bacillus subtilis based on its morphological,physiological and biochemical characteristics and phylogenetic analysis of 16S rDNA.In addition,our data showed that it can colonize in the rhizosphere and survive for a long time,forming the dominant flora,with broad application prospect.Finally,we were surprised to find that the antibacterial metabolites secreted by the antagonistic bacteria was one of the mechanisms of its inhibition of A.flavus and aflatoxin.This will provide us with new ideas and perspectives on the effective prevention and control of aflatoxin contamination in corn and corn oil.
文摘Protective effects of calcium antagonists, chlorpromazine (CPZ) and nimodepine (NI-MO), on cadmium-induced toxicity were investigated. After giving CdCl2 (0. 44mg Cd/kg,ip), CPZ (5mg/kg, ip) or NIMO (8mg/kg, po) were administered every day to Sprague-Dawley (S. D. ) rats for a week. Then, urinary N- acetyl-β-D- glucosaminidase (NAG ), uri -nary cadmium and bloocl cadmium were measured. The accumulation of cadmium in the kid-ney cortex, content of renal calmodulin, hemoglobin and the ultrastructural damage of proxi-mal convoluted tubules of rats were examined three weeks after the last administration. Re-sults indicated that the calcium antagonists partly protected against toxic effects induced bycadmium in different manners. These data provide further evidence for the new hypothesisthat the cross effect of cadmium and calcium in calmodulin regulated systems may be responsi-ble for the mechanism of cadmium intoxication. 'The results suggested that the calcium antag-onists could be a new and promising approach in the therapy of heavy metaLinduced diseases
基金Supported by Natural Science Foundation of Chongqing City(CSTC,2009BB1294)~~
文摘[ Objective ] The paper was to study the growth-promoting and antagonistic action of endophytic bacteria strains Itb57 and Itb295 of tobacco to explore their functions in biological control. [ Method] The growth-promoting effects of bacterial suspension ~ff endophytic bacteria Itb57 and Itb295 on tobacco seedling un- der different treatment modes were studied using potting method in greenhouse. The antagonistic action of bacterial suspension of endophytic bacteria Itb57 and Itb295 on Phytophthora nicotianae, Alternaria alternata and Botrytis cinerea were measured by duel culture method. [ Result] Bacterial suspensions of enduphytic bacteria Itb57 and Itb295 had certain growth-promoting effects on tobacco seedling, which could significantly increase the fresh weight and dry weight in aerial part; the growth-promoting effect of soaking ＋ spraying and irrigating treatment was the best. Itb57 strain had good antagonistic action against P. nicotianae. A. alterna- ta and B. cinerea, while Itb295 strain only had good antifungal effect against P. nicotianae. [ Conclusion] The results provided basis for the study and application of tobacco endophytic bacteria strains Itb57 and Itb295 in biocontrol of tobacco diseases.
基金Project supported by Wenzhou Technology Bureau (No. S2002A015)and Wenzhou Normal College (No. 2003Z20), China
文摘The mutagemc effects of microwave and chromium trioxide （CrO3） on Vicia faba root tip were studied. Micronucleus assay and chromosomal aberration assay were used to determine the mitotic index, the micronucleus frequency and chromosomal aberration frequency of Vicia faba root tip cells induced by microwave and CrO3. The results showed that the micronucleus frequency decreased, and that the mitotic index and chromosomal aberration frequency showed linear dose responses to CrO3, in treatment of microwave for 5 s. In microwave of 25 s, the mitotic index decreased, the micronucleus frequency and chromosomal aberration frequency increased with increase of CrO3 concentration. We concluded that microwave and CrO3 had antagonistic effect on the mitotic index of Vicia faba root tip cells, but had synergetic effect on micronucleus frequency and chromosomal aberration frequency of Viciafaba root tip cells.
基金Supported by Natural Science Foundation of China(31471555)Special Fund for Basic Scientific Research of Central Nonprofit Research Institutes(1630052016010)The Earmarked Fund for Modern Agro-industry(Sugar Crop Industry)Technology Research System(CARS-170301)
文摘[Objectives] This study was conducted to obtain actinomycetes strains having antagonistic effect on Ustilago scitaminea Syd.[Methods] At first, actinomycetes strains were isolated from 22 soil samples in Hainan sugarcane regions. Then, antagonistic actinomycetes against U. scitaminea were screened by confrontation culture. Finally, the taxonomic status of antagonistic actinomycetes was determined using 16S rDNA.[Results] From the 22 samples, 984 actinomycetes strains were isolated. From all the isolated strains, 23 antagonistic actinomycetes strains were obtained through primary screening, and one strains with better antagonistic effect was then obtained through secondary screening, and designated FAS. 16S rDNA identification showed that strain FAS shared 99% sequence similarity with Streptomyces cealestis US24. A phylogenetic tree was built with MAGE 7.0 software, and the results showed that strain FAS had the shortest genetic distance with S. caelestis US24. Therefore, the actinomycetes FAS was determined as S. caelestis .[Conclusions] This study provides a new biocontrol method for the biological control of sugarcane smut, thereby ensuring sustainable development of sugarcane industry and sugar industry.
基金supported by the National Natural Science Foundation of China(No.21677033)the Natural Science Foundation of Science and Technology Department of Fujian Government(No.2021N0005)Fujian Agriculture and Forestry University Innovation Fund(Nos.CXZX2020049A,KFb22047XA)。
文摘Selenium(Se)in paddy rice is one of the significant sources of human Se nutrition.However,the effect of arsenic(As)pollution in soil on the translocation of Se species in rice plants is unclear.In this research,a pot experiment was designed to examine the effect of the addition of 50 mg As/kg soil as arsenite or arsenate on the migration of Se species from soil to indica Minghui 63 and Luyoumingzhan.The results showed that the antagonism between inorganic As and Se was closely related to the rice cultivar and Se oxidation state in soil.Relative to the standalone selenate treatment,arsenite significantly(p<0.05)decreased the accumulation of selenocystine,selenomethionine and selenate in the roots,stems,sheaths,leaves,brans and kernels of both cultivars by 21.4%-100.0%,40.0%-100.0%,41.0%-100%,5.4%-96.3%,11.3%-100.0% and 26.2%-39.7% respectively,except for selenocystine in the kernels of indica Minghui 63 and selenomethionine in the leaves of indica Minghui 63 and the stems of indica Luyoumingzhan.Arsenate also decreased(p<0.05)the accumulation of selenocystine,selenomethionine and selenate in the roots,stems,brans and kernels of both cultivars by 34.9%-100.0%,30.2%-100.0%,11.3%-100.0% and 5.6%-39.6%respectively,except for selenate in the stems of indica Minghui 63.However,relative to the standalone selenite treatment,arsenite and arsenate decreased(p<0.05)the accumulation of selenocystine,selenomethionine and selenite only in the roots of indica Minghui 63 by 45.5%-100.0%.Our results suggested that arsenite and arsenate had better antagonism toward Se species in selenate-added soil than that in selenite-added soil;moreover,arsenite had a higher inhibiting effect on the accumulation of Se species than arsenate.
文摘Inhibitive properties of NAC and NAM as well as their mixture have been investigated in two different corrosive media through potentiodynamic polarization and electrochemical impedance spectroscopy at 298 K. These electrochemical measurements indicate that the inhibition efficiency increases with the concentration for each of the inhibitors used separately as well as for their mixture. In both cases, the combination behaves as mixed type inhibitor with a great cathodic tendency. NaCl 3.5% highlights an antagonist effect of NAM which reduces the effectiveness of NAC whereas HNO3 1M shows a synergistic effect between them.
文摘Oxidation stability of lubricating oil is critical for the smooth operation of industrial equipment such as turbines.Sludge formation is a major issue in turbine operation.Currently,the turbine oil industry employs antioxidants,especially,the combination of aminic and phenolic antioxidants,as the key additives to reduce sludge formation.Aromatic amines,primarily PANA,are considered as the most effective antioxidants in terms of oxidation induction time(OIT)measured by the RPVOT test.However,PANA is also a sludge former.Phenolic antioxidants are normally used in combination with the aminic antioxidants.It is widely believed that there exists a synergistic effect between the phenolic and aminic antioxidants.Regarding the interaction mechanism between the two types of antioxidants,it is generally accepted that phenolics act as a hydrogen donor to help regenerate the consumed aminic antioxidants.This mechanism can only explain some of the phenomena observed in field practice,but there are many other questions remaining unanswered including the antagonistic effect between PANA and phenolics.In this study,we used HPLC,FTIR and LC-MS to monitor the degradation products of the oil systems that were formulated with various aminic and phenolic antioxidants.For the APANA alone system,we identified the formation of dimers and trimers of APANA.For the PANA alone system,we identified the formation of dimers and tetramers.The dimers,trimers,and tetramers of PANA have very limited solubility.These findings therefore help explain why PANA is a sludge former.The oligomerizations(dimerization,trimerization,etc.)regenerate the N-H functionality,thus explaining why the PANA as well as other amines are very effective antioxidants.For the PANA/phenolic system,the oligomers of PANA were greatly reduced.Instead,we identified species that were formed by the recombination of the PANA radicals,or the PANA oligomeric radicals with the phenolic radicals.This,to our knowledge,has not been reported so far.The recombination of aminyl radicals and the phenolic radicals decreases the capability of regenerating the N-H functionality,which helps explain the antagonistic effect observed in the PANA/phenolic system.It also suggests that the phenolic antioxidants are very important in suppressing the sludge formation in the turbine oil system because the recombination products of PANA and phenolics have much better solubility than the PANA oligomers.
文摘DFT quantum chemical computations have been carried out at the B3LYP/6-31G (d) level. Full geometry optimization has been performed and equilibrium geometries for a new series of phenyl thiazoles have been located. Ground state electronic properties, charge density distributions, dipole moments and its components have been calculated and reported. Effect of substituents on the geometry and on the polarization of the studied series of compounds are analyzed and discussed. Some structural features have been pinpointed to underline the affinity and selectivity of the studied compounds as adenosine A3-receptor antagonists. Results of the present work indicate that activity towards A3 receptor sites is directly correlated with both of the polarity and the co-planarity of the thiazole.
基金Project supported by the National Natural Science Foundation of China,No.39770861.and JANSSEN Science Research Foundation.
文摘AIM: To study the effects of aminoguanidine (AG) and two L-arginine analogues N(omega)-nitro-L-arginine methyl ester (L-NAME) and N(omega)-nitro-L-arginine (L-NNA) on nitric oxide (NO) production induced by cytokines (TNF-alpha, IL-1 beta, and IFN-gamma) and bacterial lipopolysaccharide (LPS) mixture (CM) in the cultured rat hepatocytes, and examine their mechanisms action. METHODS: Rat hepatocytes were incubated with AG, L-NAME, L-NNA, Actinomycin D (ActD) and dexamethasone in a medium containing CM (LPS plus TNF-alpha, IL-1 beta, and IFN-gamma) for 24h. NO production in the cultured supernatant was measured with the Griess reaction. Intracellular cGMP level was detected with radioimmunoassy. RESULTS: NO production was markedly blocked by AG and L-NAME in a dose-dependent manner under inflammatory stimuli condition triggered by CM in vitro. The rate of the maximum inhibitory effects of L-NAME (38.9%) was less potent than that obtained with AG(53.7%, P 【 0.05). There was no significant difference between the inhibitory effects of AG and two L-arginine analogues on intracellular cGMP accumulation in rat cultured hepatocytes. Non-specific NOS expression inhibitor dexamethasone (DEX)and iNOS mRNA transcriptional inhibitor ActD also significantly inhibited CM-induced NO production. AG(0.1 mmol x L(-1)) and ActD (0.2 ng x L(-1)) were equipotent in decreasing NO production induced by inflammatory stimuli in vitro, and both effects were more potent than that induced by non-selectivity NOS activity inhibitor L-NAME (0.1 mmol x L(-1)) under similar stimuli conditions (P【0.01). CONCLUSION: AG is a potent selective inhibitor of inducible isoform of NOS,and the mechanism of action may be not only competitive inhibition in the substrate level, but also the gene expression level in rat hepatocytes.
