AIM: To investigate the photodynamic inhibitory effects of Elsinochrome A (EA), Hypocrellin A (HA) and Hypocrellin B (HB) on human colorectal carcinoma Hce-8693 cells and rhesus monkey embryonic stem R366.4 cells, via...AIM: To investigate the photodynamic inhibitory effects of Elsinochrome A (EA), Hypocrellin A (HA) and Hypocrellin B (HB) on human colorectal carcinoma Hce-8693 cells and rhesus monkey embryonic stem R366.4 cells, via inducing apoptosis.METHODS: EA, HA and HB were extracted from metabolites of Hypomyces (Fr) Tul.Sp. R366.4 cells or Hce8693 cells were cultured with different concentrations of EA, HA or HB respectively, irradiated and incubated with fresh medium for 2 h. Cell cycle analysis was performed by flow cytometry (FCM). Data were expressed as means ±SD and analysis of variance and Student' t-test for individual comparisons.RESULTS: The photodynamic bioactivity of EA was first reported in this study. After irradiation for 5 min, 6 min, 10 min or 20 min, photoactivated EA at lower concentrations,which were 10-7 Mol/L, 10-6 Mol/L, 10-5 Mol/L respectively,had no cytotoxic effects on R366.4 ES ceils. Whereas, all of the three perylenequinones could induce apoptosis with a dose-dependent manner when Hce-8693 cells were incubated with photoactivated EA, HA and HB respectively. When Hce-8693 cells were incubated with EA at 10-6 Mol/L and irradiated 5 lin, 6 min, 10 min and 20 min respectively,the rates of EA-induced apoptosis were 0, 0, 13.4 % and 40.5 %. While the rates of HA-induced apoptosis were 29.5 %, 32.0 %, 40.2 % and 22.6 %. And the rates of HBinduced apoptosis were 0, 0, 0 and 13.7 % respectively.Meanwhile, after 10-5 Mol/L treatment, the rates of EA-induced apoptosis were 32.7 %, 19.3 %, 26.4 % and 52.7 %, the rates of HA-induced apoptosis were 47.2 %, 39.1%, 45.2% and 56.6 %, and the rates of HB-induced apoptosis were 0, 0, 20.0 % and 13.9 % respectively.CONCLUSION: EA, HA and HB have significant anti-cancer activity. The order of photodynamic inhibitory effects on tumor cells would be approximately HA>EA>HB. The molecular mechanisms of apoptosis may not be induced by reactive oxygen species and are worth further investigation.展开更多
From the ethanol extract of the whole plant of Boschniakia himalaica Hook. f. et. Thoms, a new and two known lignans have been isolated and identified as 7-methoxypinoresino 1, pinoresinol 2, and pinoresinol-O--D-gluc...From the ethanol extract of the whole plant of Boschniakia himalaica Hook. f. et. Thoms, a new and two known lignans have been isolated and identified as 7-methoxypinoresino 1, pinoresinol 2, and pinoresinol-O--D-glucopyranoside 3 respectively. Their structures have been established by spectroscopic methods.展开更多
From rhizomes of Hemsleya giganthy collected in Shichuan of China, 16 compounds were isolated. Among them, three compounds (8, 9, 15) are new natural products called Hemslecins G; Hemsgiganosides A and B; respectivel...From rhizomes of Hemsleya giganthy collected in Shichuan of China, 16 compounds were isolated. Among them, three compounds (8, 9, 15) are new natural products called Hemslecins G; Hemsgiganosides A and B; respectively. Their structures were elucidated as 7- hydroxy-23, 24-dihydro-cucurbitacin F-25-O-acetate (8); 3-O-(6-butyl ester-)-b-D-glu- curono- pyranosyl)-oleanolic acid-28-O-a-L-arabinopyranoside(9); 3-O-b-D-glucuropyranosyl oleanolic acid -28-O-b-D-gluco pyranosyl-(16)- b-D-glucopyranoside(15) by spectroscopic and chemical means.展开更多
We present a discrete time single-server two-level mixed service polling systems with two queue types, one center queue and N normal queues. Two-level means the center queue will be successive served after each normal...We present a discrete time single-server two-level mixed service polling systems with two queue types, one center queue and N normal queues. Two-level means the center queue will be successive served after each normal queue. In the first level, server visits between the center queue and the normal queue. In the second level, normal queues are polled by a cyclic order. Mixed service means the service discipline are exhaustive for center queue, and parallel 1-limited for normal queues. We propose an imbedded Markov chain framework to drive the closed-form expressions for the mean cycle time, mean queue length, and mean waiting time. Numerical examples demonstrate that theoretical and simulation results are identical the new system efficiently differentiates priorities.展开更多
The local influence analysis is an important problem in statistical inference and some models have been discussed in many literatures This paper deals with the problem of assessing local influences in a multivariate t...The local influence analysis is an important problem in statistical inference and some models have been discussed in many literatures This paper deals with the problem of assessing local influences in a multivariate t-model with Rao's simple struc-ture(RSS). Based on Cook's likelihood displacement, the effects of some minor perturbation on the statistical inference is assessed. As an application, a common covariance-weighted perturbation is thoroughly discussed.展开更多
In this paper, a lemma as a new method to calculate the Hausdorff measure of fractal is given. And then the exact values of Hausdorff measure of a class of Sierpinski sets which satisfy balance distribution and dimens...In this paper, a lemma as a new method to calculate the Hausdorff measure of fractal is given. And then the exact values of Hausdorff measure of a class of Sierpinski sets which satisfy balance distribution and dimension ≤ 1 are obtained.展开更多
Twenty-six novel benzoylphenylurea chitin inhibitor derivatives have been synthesized in over 30~50% yield from chlorothalonil 1 via sequential fluorine exchange, aminolysis, hydrolysis, decarboxylation and acylation ...Twenty-six novel benzoylphenylurea chitin inhibitor derivatives have been synthesized in over 30~50% yield from chlorothalonil 1 via sequential fluorine exchange, aminolysis, hydrolysis, decarboxylation and acylation reactions.展开更多
To study the effect of tobacco growth on Trichoderma population, we in vestigated the occurrence of Trichoderma species in the rhizosphere of tob acco plant during the period from transplanting (June) to harvesting (O...To study the effect of tobacco growth on Trichoderma population, we in vestigated the occurrence of Trichoderma species in the rhizosphere of tob acco plant during the period from transplanting (June) to harvesting (October) and measured relative environmental factors. Eleven species of Trichoderma we re isolated, among which T.harzianum, T.viride, T.hamatum, T.atroviride, T.lo ngibrachiatum, T.virens, T.koningii were identified, other four species Ty1, Ty2, Ty3, Ty4 are new species. Of the species which occurred at high frequencies , T.harzianum and T.hamatum were most abundant in the July and T. viride in the August. The occurrence of the above three abundant species corr elates significantly with the developmental phase of tobacco and correlates appa rently with the soil moisture content, but not with the temperature. For the oth er eight species, no obvious correlation was found between the above factors and them. Based on nucleotide sequences of the internal transcribed spacer (ITS) regions of the rDNA cluster (ITS1and 2) and partial sequences of translation elongation f ac tor 1-alpha (tef1a), phylogenetic position of four new species was determined. Ty2 is additions to Trichoderma section and Ty3.Ty9.Ty10 are additions to sec tion Pachybasium.展开更多
Regularity of the initial atmospheric corrosion of A3 steel in the presence of NaCI was investigated. The results showed that NaCI can accelerate the corrosion of A3 steel. Dry mass gain of A3 steel in the presence of...Regularity of the initial atmospheric corrosion of A3 steel in the presence of NaCI was investigated. The results showed that NaCI can accelerate the corrosion of A3 steel. Dry mass gain of A3 steel in the presence of NaCI deposition increases with the exposure time, which can be correlated by using exponential decay function. The relationship between dry mass gain and amount of NaCI deposition at a certain exposure time follows a quadratic function. More amount of NaCI deposition will slow down the corrosion rate to some extent after exposure for a certain time. SEM/EDAX was used to characterize the corrosion surface and products. The surfaces of the NaCI treated A3 steel were obviously uneven, and some tiny crevices appear in the corrosion products that could help O2 transmit to the inner layer. The amount of oxygen in atomic percentage in the corrosion products increases with the amount of NaCI deposition.展开更多
I type system model of CCCAM(Contention-Collision Cancellation Access Mode) is studied through mathematical modelling and simulation. There are two innovations: (1) in the process of mathematical modelling, the instan...I type system model of CCCAM(Contention-Collision Cancellation Access Mode) is studied through mathematical modelling and simulation. There are two innovations: (1) in the process of mathematical modelling, the instance of 'serving customers unsuccessfully' is taken into account; (2) the time at which customers depart after having been served successfully are chosen to be the embedded point, thereby 'free period' is introduced reasonably. So the mathematical modelling and analysis result in this paper are significant for application of wire star LAN and wireless star LAN.展开更多
Five neolignans including four new ones were obtained from the seed endotheliums of Trewia nudiflora L. Their structures were determined to be 9'-methyl americanol A(1), 9'-methyl isoamericanol A(2), 9'-et...Five neolignans including four new ones were obtained from the seed endotheliums of Trewia nudiflora L. Their structures were determined to be 9'-methyl americanol A(1), 9'-methyl isoamericanol A(2), 9'-ethyl americanol A(3), 9'-butyl americanol A(4), and americanin (5). Two acetylated products 3,4-diacetyl americanin (5a) and 3,4,9-triacetyl americanin (5b) had been prepared from compound 5. All of these compounds were investigated on antibacterial assays when carbenicillin sodium, streptomycin sulfate and rifampicin were used as positive controls. Compounds 4 and 5 exhibited antibacterial activities against gram-positive bacterium Staphylococcus aureus and gram-negative bacterium Mycobacterium tuberculosis at the minimum inhibitory concentrations (MIC) of 50μg/mL and 100μg/mE respectively, but 5a and 5b did not exhibit antibacterial activity at 200μg/disk.展开更多
Phytochemical investigation of Lagotis yunnanensis led to the isolation and identification of a new iridoid glucoside 1, named as 10-O-(3,4-dimethoxy-(E)-cinnamoyl)aucubin. Its structure was elucidated by spectroscopi...Phytochemical investigation of Lagotis yunnanensis led to the isolation and identification of a new iridoid glucoside 1, named as 10-O-(3,4-dimethoxy-(E)-cinnamoyl)aucubin. Its structure was elucidated by spectroscopie methods.展开更多
By using some differential inequality, a second-order delay differential equation(r(t)x′(t))′ + p(t)x(q(t)) = 0has been investigated and some necessary condition for this equation has a nonoscillatorysolution and so...By using some differential inequality, a second-order delay differential equation(r(t)x′(t))′ + p(t)x(q(t)) = 0has been investigated and some necessary condition for this equation has a nonoscillatorysolution and some sufficient condition which ensures that all of the solutions of the aboveequation are oscillatory are obtained.展开更多
A novel manganiferous polymeric complex [(imid)2(ta)Mn0.5]n (imid = imidazole, ta = terephthalato) was synthesized by the hydrothermal reaction of MnO2, terephthalic acid, imidazole, and H2O. Structure analysis indica...A novel manganiferous polymeric complex [(imid)2(ta)Mn0.5]n (imid = imidazole, ta = terephthalato) was synthesized by the hydrothermal reaction of MnO2, terephthalic acid, imidazole, and H2O. Structure analysis indicates that the compound crystallizes in the triclinic system, space group P1, with a = 8.1500(16), b = 8.5100(17), c = 9.0500(18) ?, α = 72.77(3), β = 65.50(3), γ = 77.22(3)o, V = 542.02(19) ?3, Z = 2, Dc = 1.505 g/cm3, F(000) = 253, Mr = 245.69, μ(MoKα) = 0.655 mm-1, R = 0.0733 and wR = 0.1703 for 1673 observed reflections (I > 2σ(I)). The compound is characteristic of a zigzag chain-like framework built up of ta bridge and (Imid)4Mn group. The 1-D frameworks are held together by H-bonds between the dangling N–H donors from imid and O acceptors from ta.展开更多
China is one of the twelve prolific biological diversity countries in the world, and nematophagous fungol resources are very abundant. In this paper, the research advance of nematophagous fungi is discussed from six a...China is one of the twelve prolific biological diversity countries in the world, and nematophagous fungol resources are very abundant. In this paper, the research advance of nematophagous fungi is discussed from six aspects: resources introduction, biology of nematophagous fungi, the application of biocontrol agents, fungistsis in soils, research on nematicidal metabolites and molecular biology on nematophagous fungi. Concerning Clonostachys rosea, the alkaline protease (designated Lmz1) was purified from supernatant of C. rosea which showed a molecular mass of 33 kDa, pI of pH 10.5, optimum temperature of 55- 60 ℃. and optimum pH between 11.0-12.0. N-terminal sequence of Lmz1 was determined by electoblotting enzyme protein to PVDF membrane as NH2-A-T-Q-S-N-A-P-?-?-?. The degenerate primer was designed according to terminal sequence for cDNA gene encoding mature protein of Lmz1 by 3’RACE system for rapid amplification of cDNA ends. To express successfully a fungal alkaline protease (Lmz1) in a high level expression system. The specific primers with EcoRI recognition site and extra bases were designed. The cDNA gene encoding mature protease (Lmz1) was amplified with high fidelity pfu DNA polymerase and specific primers against total cDNA population of C. rosea. The recombinant expression vector contain desired DNA fragment was correctly constructed and introduced into yeast host Pichia pastoris GS115 by electroporation. The recombinant alkaline protease was characterized by protease activity, PCR amplification against yeast total DNA, ELISA and western blotting. It demonstrated a molecular mass of 42 kDa based on blot analysis. The expression level of Lmz1 was approximately 9 mg/mL by UV spectrophotometric method.展开更多
Two new iridoid glucosides 1 and 2, 10-O-(3, 4-dimethoxy-(E)-cinnamoyl)catalpol and 10-O-(3, 4-dimethoxy-(Z)-cinnamoyl)catalpol, were isolated from Lagotis yunnanensis. Their structures were elucidated by spectroscop...Two new iridoid glucosides 1 and 2, 10-O-(3, 4-dimethoxy-(E)-cinnamoyl)catalpol and 10-O-(3, 4-dimethoxy-(Z)-cinnamoyl)catalpol, were isolated from Lagotis yunnanensis. Their structures were elucidated by spectroscopic methods.展开更多
Two new diacetylated flavonol glycosides, kampferol-3-O--3? 6?diacetylglucopyrano- side and quercetin-3-O--3? 6?diacetylglucopyranoside were isolated from knoxia corymbosa. Their structures were elucidated by spectro...Two new diacetylated flavonol glycosides, kampferol-3-O--3? 6?diacetylglucopyrano- side and quercetin-3-O--3? 6?diacetylglucopyranoside were isolated from knoxia corymbosa. Their structures were elucidated by spectroscopic evidents.展开更多
Dianchi Lake is one of the lakes with the richest phosphorus source in the world, in which the P2O5 content in the bottom sediments reaches averagely 0.51 wt % and maximally 1.92%. Studies indicate that this: extremel...Dianchi Lake is one of the lakes with the richest phosphorus source in the world, in which the P2O5 content in the bottom sediments reaches averagely 0.51 wt % and maximally 1.92%. Studies indicate that this: extremely P-rich state is attributed mainly to the large volume (as high as hundred thousands of tons) of phosphatic matter coming into the lake as many rivers feeding the lake pass through a vast area of phosphate-mining districts, which then undergo weathering and particularly some human activities, including waste water discharge. When phosphatic matter enters the lake, its grained parts are firstly decomposed by phosphorus-decomposing bacteria, and finally accumulated in some geographically special parts of the lake, such as a bay area where water flow is much more slower than elsewhere in the lake. With the involvement of phosphorus-concentrating bacteria, the accumulated phosphates in the bottom sludge ultimately form phosphate minerals through deep-burial diagenesis.展开更多
Rate constants for the reactions of NO3 and SO4 radicals with oxalic acid and oxalate anions in aqueous solution have been measured using pulse radiolysis and laser flash photolysis.
Two new ent-kaurane diterpenoids, sculponeatins L (1) and M (2), were isolated from the EtOAc extract of Isodon sculponeata. Their structures were elucidated by spectroscopic evidences. The cytotoxicities of 1 and 2...Two new ent-kaurane diterpenoids, sculponeatins L (1) and M (2), were isolated from the EtOAc extract of Isodon sculponeata. Their structures were elucidated by spectroscopic evidences. The cytotoxicities of 1 and 2 against human tumor cells K562 and T24 were tested.展开更多
基金National Natural Science Foundation of China,No.980174Natural Scientific Foundation of Yunnan Province,No.CO 106M
文摘AIM: To investigate the photodynamic inhibitory effects of Elsinochrome A (EA), Hypocrellin A (HA) and Hypocrellin B (HB) on human colorectal carcinoma Hce-8693 cells and rhesus monkey embryonic stem R366.4 cells, via inducing apoptosis.METHODS: EA, HA and HB were extracted from metabolites of Hypomyces (Fr) Tul.Sp. R366.4 cells or Hce8693 cells were cultured with different concentrations of EA, HA or HB respectively, irradiated and incubated with fresh medium for 2 h. Cell cycle analysis was performed by flow cytometry (FCM). Data were expressed as means ±SD and analysis of variance and Student' t-test for individual comparisons.RESULTS: The photodynamic bioactivity of EA was first reported in this study. After irradiation for 5 min, 6 min, 10 min or 20 min, photoactivated EA at lower concentrations,which were 10-7 Mol/L, 10-6 Mol/L, 10-5 Mol/L respectively,had no cytotoxic effects on R366.4 ES ceils. Whereas, all of the three perylenequinones could induce apoptosis with a dose-dependent manner when Hce-8693 cells were incubated with photoactivated EA, HA and HB respectively. When Hce-8693 cells were incubated with EA at 10-6 Mol/L and irradiated 5 lin, 6 min, 10 min and 20 min respectively,the rates of EA-induced apoptosis were 0, 0, 13.4 % and 40.5 %. While the rates of HA-induced apoptosis were 29.5 %, 32.0 %, 40.2 % and 22.6 %. And the rates of HBinduced apoptosis were 0, 0, 0 and 13.7 % respectively.Meanwhile, after 10-5 Mol/L treatment, the rates of EA-induced apoptosis were 32.7 %, 19.3 %, 26.4 % and 52.7 %, the rates of HA-induced apoptosis were 47.2 %, 39.1%, 45.2% and 56.6 %, and the rates of HB-induced apoptosis were 0, 0, 20.0 % and 13.9 % respectively.CONCLUSION: EA, HA and HB have significant anti-cancer activity. The order of photodynamic inhibitory effects on tumor cells would be approximately HA>EA>HB. The molecular mechanisms of apoptosis may not be induced by reactive oxygen species and are worth further investigation.
文摘From the ethanol extract of the whole plant of Boschniakia himalaica Hook. f. et. Thoms, a new and two known lignans have been isolated and identified as 7-methoxypinoresino 1, pinoresinol 2, and pinoresinol-O--D-glucopyranoside 3 respectively. Their structures have been established by spectroscopic methods.
基金The authors are grateful to the financial support of the National Natural Science Foundation of China(Grant No.39970086)Natural Science Foundation of Yunnan(Grant No.98C089M)also thank the members of analytical group in Phytochemistry LaboratoTy,Kunming Institute of Botany for their measuring spectral data.
文摘From rhizomes of Hemsleya giganthy collected in Shichuan of China, 16 compounds were isolated. Among them, three compounds (8, 9, 15) are new natural products called Hemslecins G; Hemsgiganosides A and B; respectively. Their structures were elucidated as 7- hydroxy-23, 24-dihydro-cucurbitacin F-25-O-acetate (8); 3-O-(6-butyl ester-)-b-D-glu- curono- pyranosyl)-oleanolic acid-28-O-a-L-arabinopyranoside(9); 3-O-b-D-glucuropyranosyl oleanolic acid -28-O-b-D-gluco pyranosyl-(16)- b-D-glucopyranoside(15) by spectroscopic and chemical means.
基金Supported by the National Natural Science Foundation of China (No. 61072079)Science Foundation of Yunnan Provincial Department (No. 2011Y117)
文摘We present a discrete time single-server two-level mixed service polling systems with two queue types, one center queue and N normal queues. Two-level means the center queue will be successive served after each normal queue. In the first level, server visits between the center queue and the normal queue. In the second level, normal queues are polled by a cyclic order. Mixed service means the service discipline are exhaustive for center queue, and parallel 1-limited for normal queues. We propose an imbedded Markov chain framework to drive the closed-form expressions for the mean cycle time, mean queue length, and mean waiting time. Numerical examples demonstrate that theoretical and simulation results are identical the new system efficiently differentiates priorities.
文摘The local influence analysis is an important problem in statistical inference and some models have been discussed in many literatures This paper deals with the problem of assessing local influences in a multivariate t-model with Rao's simple struc-ture(RSS). Based on Cook's likelihood displacement, the effects of some minor perturbation on the statistical inference is assessed. As an application, a common covariance-weighted perturbation is thoroughly discussed.
文摘In this paper, a lemma as a new method to calculate the Hausdorff measure of fractal is given. And then the exact values of Hausdorff measure of a class of Sierpinski sets which satisfy balance distribution and dimension ≤ 1 are obtained.
基金support of the Natural Science Foundation of Yunnan Province(1999B0005M)the Open Foundation of State Key Laboratory of Elemento-Organic Chemistry,Nankai University
文摘Twenty-six novel benzoylphenylurea chitin inhibitor derivatives have been synthesized in over 30~50% yield from chlorothalonil 1 via sequential fluorine exchange, aminolysis, hydrolysis, decarboxylation and acylation reactions.
文摘To study the effect of tobacco growth on Trichoderma population, we in vestigated the occurrence of Trichoderma species in the rhizosphere of tob acco plant during the period from transplanting (June) to harvesting (October) and measured relative environmental factors. Eleven species of Trichoderma we re isolated, among which T.harzianum, T.viride, T.hamatum, T.atroviride, T.lo ngibrachiatum, T.virens, T.koningii were identified, other four species Ty1, Ty2, Ty3, Ty4 are new species. Of the species which occurred at high frequencies , T.harzianum and T.hamatum were most abundant in the July and T. viride in the August. The occurrence of the above three abundant species corr elates significantly with the developmental phase of tobacco and correlates appa rently with the soil moisture content, but not with the temperature. For the oth er eight species, no obvious correlation was found between the above factors and them. Based on nucleotide sequences of the internal transcribed spacer (ITS) regions of the rDNA cluster (ITS1and 2) and partial sequences of translation elongation f ac tor 1-alpha (tef1a), phylogenetic position of four new species was determined. Ty2 is additions to Trichoderma section and Ty3.Ty9.Ty10 are additions to sec tion Pachybasium.
基金This work was financially supported by the National Natural Science Foundation of China. The number of the project is 5989914. The authors are grateful to Ms. Ping Wan for English diction.
文摘Regularity of the initial atmospheric corrosion of A3 steel in the presence of NaCI was investigated. The results showed that NaCI can accelerate the corrosion of A3 steel. Dry mass gain of A3 steel in the presence of NaCI deposition increases with the exposure time, which can be correlated by using exponential decay function. The relationship between dry mass gain and amount of NaCI deposition at a certain exposure time follows a quadratic function. More amount of NaCI deposition will slow down the corrosion rate to some extent after exposure for a certain time. SEM/EDAX was used to characterize the corrosion surface and products. The surfaces of the NaCI treated A3 steel were obviously uneven, and some tiny crevices appear in the corrosion products that could help O2 transmit to the inner layer. The amount of oxygen in atomic percentage in the corrosion products increases with the amount of NaCI deposition.
基金Supported by Natural Science Foundation of Qingdao University
文摘I type system model of CCCAM(Contention-Collision Cancellation Access Mode) is studied through mathematical modelling and simulation. There are two innovations: (1) in the process of mathematical modelling, the instance of 'serving customers unsuccessfully' is taken into account; (2) the time at which customers depart after having been served successfully are chosen to be the embedded point, thereby 'free period' is introduced reasonably. So the mathematical modelling and analysis result in this paper are significant for application of wire star LAN and wireless star LAN.
文摘Five neolignans including four new ones were obtained from the seed endotheliums of Trewia nudiflora L. Their structures were determined to be 9'-methyl americanol A(1), 9'-methyl isoamericanol A(2), 9'-ethyl americanol A(3), 9'-butyl americanol A(4), and americanin (5). Two acetylated products 3,4-diacetyl americanin (5a) and 3,4,9-triacetyl americanin (5b) had been prepared from compound 5. All of these compounds were investigated on antibacterial assays when carbenicillin sodium, streptomycin sulfate and rifampicin were used as positive controls. Compounds 4 and 5 exhibited antibacterial activities against gram-positive bacterium Staphylococcus aureus and gram-negative bacterium Mycobacterium tuberculosis at the minimum inhibitory concentrations (MIC) of 50μg/mL and 100μg/mE respectively, but 5a and 5b did not exhibit antibacterial activity at 200μg/disk.
文摘Phytochemical investigation of Lagotis yunnanensis led to the isolation and identification of a new iridoid glucoside 1, named as 10-O-(3,4-dimethoxy-(E)-cinnamoyl)aucubin. Its structure was elucidated by spectroscopie methods.
基金Supported by the National Natural Science Foundation of China(10061004) Supported by the Natural Sciences Foundation of Yunnan province(2003A0001M)
文摘By using some differential inequality, a second-order delay differential equation(r(t)x′(t))′ + p(t)x(q(t)) = 0has been investigated and some necessary condition for this equation has a nonoscillatorysolution and some sufficient condition which ensures that all of the solutions of the aboveequation are oscillatory are obtained.
基金This project was supported by the Key Project of Chinese Ministry of Education and the Natural Science Foundation of Yunnan Province (2002E0004Q)
文摘A novel manganiferous polymeric complex [(imid)2(ta)Mn0.5]n (imid = imidazole, ta = terephthalato) was synthesized by the hydrothermal reaction of MnO2, terephthalic acid, imidazole, and H2O. Structure analysis indicates that the compound crystallizes in the triclinic system, space group P1, with a = 8.1500(16), b = 8.5100(17), c = 9.0500(18) ?, α = 72.77(3), β = 65.50(3), γ = 77.22(3)o, V = 542.02(19) ?3, Z = 2, Dc = 1.505 g/cm3, F(000) = 253, Mr = 245.69, μ(MoKα) = 0.655 mm-1, R = 0.0733 and wR = 0.1703 for 1673 observed reflections (I > 2σ(I)). The compound is characteristic of a zigzag chain-like framework built up of ta bridge and (Imid)4Mn group. The 1-D frameworks are held together by H-bonds between the dangling N–H donors from imid and O acceptors from ta.
文摘China is one of the twelve prolific biological diversity countries in the world, and nematophagous fungol resources are very abundant. In this paper, the research advance of nematophagous fungi is discussed from six aspects: resources introduction, biology of nematophagous fungi, the application of biocontrol agents, fungistsis in soils, research on nematicidal metabolites and molecular biology on nematophagous fungi. Concerning Clonostachys rosea, the alkaline protease (designated Lmz1) was purified from supernatant of C. rosea which showed a molecular mass of 33 kDa, pI of pH 10.5, optimum temperature of 55- 60 ℃. and optimum pH between 11.0-12.0. N-terminal sequence of Lmz1 was determined by electoblotting enzyme protein to PVDF membrane as NH2-A-T-Q-S-N-A-P-?-?-?. The degenerate primer was designed according to terminal sequence for cDNA gene encoding mature protein of Lmz1 by 3’RACE system for rapid amplification of cDNA ends. To express successfully a fungal alkaline protease (Lmz1) in a high level expression system. The specific primers with EcoRI recognition site and extra bases were designed. The cDNA gene encoding mature protease (Lmz1) was amplified with high fidelity pfu DNA polymerase and specific primers against total cDNA population of C. rosea. The recombinant expression vector contain desired DNA fragment was correctly constructed and introduced into yeast host Pichia pastoris GS115 by electroporation. The recombinant alkaline protease was characterized by protease activity, PCR amplification against yeast total DNA, ELISA and western blotting. It demonstrated a molecular mass of 42 kDa based on blot analysis. The expression level of Lmz1 was approximately 9 mg/mL by UV spectrophotometric method.
文摘Two new iridoid glucosides 1 and 2, 10-O-(3, 4-dimethoxy-(E)-cinnamoyl)catalpol and 10-O-(3, 4-dimethoxy-(Z)-cinnamoyl)catalpol, were isolated from Lagotis yunnanensis. Their structures were elucidated by spectroscopic methods.
文摘Two new diacetylated flavonol glycosides, kampferol-3-O--3? 6?diacetylglucopyrano- side and quercetin-3-O--3? 6?diacetylglucopyranoside were isolated from knoxia corymbosa. Their structures were elucidated by spectroscopic evidents.
基金The present study is part of the results of a project(No.4987204)granted by the National Natural Science Foundation of China.
文摘Dianchi Lake is one of the lakes with the richest phosphorus source in the world, in which the P2O5 content in the bottom sediments reaches averagely 0.51 wt % and maximally 1.92%. Studies indicate that this: extremely P-rich state is attributed mainly to the large volume (as high as hundred thousands of tons) of phosphatic matter coming into the lake as many rivers feeding the lake pass through a vast area of phosphate-mining districts, which then undergo weathering and particularly some human activities, including waste water discharge. When phosphatic matter enters the lake, its grained parts are firstly decomposed by phosphorus-decomposing bacteria, and finally accumulated in some geographically special parts of the lake, such as a bay area where water flow is much more slower than elsewhere in the lake. With the involvement of phosphorus-concentrating bacteria, the accumulated phosphates in the bottom sludge ultimately form phosphate minerals through deep-burial diagenesis.
文摘Rate constants for the reactions of NO3 and SO4 radicals with oxalic acid and oxalate anions in aqueous solution have been measured using pulse radiolysis and laser flash photolysis.
文摘Two new ent-kaurane diterpenoids, sculponeatins L (1) and M (2), were isolated from the EtOAc extract of Isodon sculponeata. Their structures were elucidated by spectroscopic evidences. The cytotoxicities of 1 and 2 against human tumor cells K562 and T24 were tested.