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1.
Cinnamaldehyde, its derivatives and curcumin are reported to have strong antifungal activity. In this work we report and compare anticandidal activity of curcumin (CUR) and α-methyl cinnamaldehyde (MCD) against 38 strains of Candida (3; standard, fluconazole sensitive, 24; clinical, fluconazole sensitive, 11; clinical, fluconazole resistant). The minimum inhibitory concentrations (MIC90) of CUR ranged from 250 to 650 μg/ml for sensitive strains and from 250 to 500 μg/ml for resistant strains. MIC90 of MCD varied between 100 and 250 μg/ml and 100–200 μg/ml for sensitive and resistant strains, respectively. Higher activity of MCD as compared to CUR was further reinforced by spot assays and growth curve studies. At their respective MIC90 values, in the presence of glucose, average inhibition of H+-efflux caused by CUR and MCD against standard, clinical and resistant isolates was 24%, 31%, 32% and 54%, 52%, 54%, respectively. Inhibition of H+-extrusion leads to intracellular acidification and cell death, average pHi for control, CUR and MCD exposed cells was 6.68, 6.39 and 6.20, respectively. Scanning electron micrographs of treated cells show more extensive damage in case of MCD. Haemolytic activity of CUR and MCD at their highest MIC was 11.45% and 13.00%, respectively as against 20% shown by fluconazole at typical MIC of 30 μg/ml. In conclusion, this study shows significant anticandidal activity of CUR and MCD against both azole-resistant and sensitive clinical isolates, MCD is found to be more effective.  相似文献   

2.
Eugenol (1) and thymol (2) exhibit excellent fungicidal activity against pathogenic yeasts, including isolates resistant to azoles. The rapid irreversible action of compound-1 and compound 2 on fungal cells suggested a membrane-located target for their action. We investigated their effect on H+-ATPase mediated H+-pumping by various Candida species. Both compounds inhibit H+-ATPase activity at their respective MIC values — 500 and 100 μg/ml. Glucose stimulated H+-extrusion was also inhibited significantly by compound 1 and compound 2. Inhibition of H+-ATPase leads to intracellular acidification and cell death. Inhibition of cell growth and H+-efflux by test compounds suggests that their antifungal properties are related to their inhibitory effects on H+-ATPase.  相似文献   

3.
The plant family Cupressaceae (Coniferales) harbours diverse endophytic fungi with antifungal, antibacterial and antiproliferative activities. Here, endophytic association of a broad bacterial community with the healthy foliar tissues of Cupressus arizonica, Cupressus sempervirens, Juniperus communis and Thuja orientalis (Cupressaceae) is shown. We isolated over 69 endophytic bacterial strains of Proteobacteria, Bacilli and Actinobacteria from Cupressaceae. The initial screening for antifungal activity against Pyricularia oryzae identified eleven superior bacterial strains which were identified as Brevundimonas diminuta CAE24 (G?, Caulobacteraceae, Alphaproteobacteria); Stenotrophomonas maltophilia CAE23, CSE4, CSE12, CSE42, CSE49 and CSE62 (G?, Xanthomonadaceae, Gammaproteobacteria); Bacillus pumilus CSE66 and Bacillus subtilis POE26 (G+, Bacillaceae, Bacilli); and Microbacterium resistens CSE19 (G+, Microbacteriaceae, Actinobacteria). The dominant isolated bacterial species was S. maltophilia. This species represented 63.6% of the superior strains which was ubiquitous and also non‐host specific. In addition, the superior bacterial strains produced bioactive secondary metabolites and volatile compounds (VOCs) with antifungal activity against the fungal pathogens of Cupressaceae, that is Diplodia seriata, Phaeobotryon cupressi and Spencermartinsia viticola. The antagonistic activity of the endophytic bacteria on the target fungi was also confirmed in vitro. To our knowledge, this is the first to document such an endophytic bacterial community in Cupressaceae and its bioactivity. These findings may find application in organic agroforestry for plant disease biocontrol and in biopharmacy for lead molecule discovery.  相似文献   

4.
In vitro antifungal activity of phenylheptatriyne from Bidens cernua L. (Asteraceae) was studied using broth macrodilution method against 125 strains of yeasts including 104 clinical and other isolates of Candida spp. (C. albicans, C. krusei, C. tropicalis, C. guilliermondii, C. parapsilosis, C. glabrata, C. inconspicua), 16 strains of basidiomycetous yeasts (Cryptococcus neoformans, C. albidus, Trichosporon cutaneum, Rhodotorula glutinis) and five standard reference strains of Candida species. Phenylheptatriyne has shown significant activity against investigated strains, and the Minimal Inhibitory Concentrations for Candida spp. were determined as 12.5–50 µg/ml and for basidiomycetous yeasts as 12.5–100 µg/ml.  相似文献   

5.
《Fitoterapia》1999,70(2):187-189
The methanol extract of P. maritimum bulbs, though devoid of antibacterial activity, showed interesting antifungal activity against four Candida species, being, however, ineffective against C. albicans.  相似文献   

6.
Methanol extract of sawdust of sugi (Cryptomeria japonica) heartwood was fractionated with toluene and n-hexane to give solvent-soluble and solvent-insoluble fractions. The n-hexane-soluble fraction showed the most inhibition activity among the fractions against phytopathogenic microorganisms, namely Fusarium oxysporum, Phytophthora capsici, Pythium splendens, and Ralstonia solanacearum. Sandaracopimarinol and ferruginol, isolated from the n-hexane-soluble fraction, showed moderate antifungal activity against the three fungi and strong antibacterial activity against R. solanacearum. The content of sandaracopimarinol (7.07 g/kg based on the dried sawdust) in the heartwood was about twice that of ferruginol. Sandaracopimarinol and ferruginol strongly inhibited the growth of Gram-positive bacteria but did not show inhibitory action against Gram-negative bacteria except for R. solanacearum. The antibacterial effect of sandaracopimarinol was first found in the present study and was stronger than that of ferruginol.  相似文献   

7.
The antitermitic activities of leaf oils and their constituents, taken from three clones of Eucalyptus camaldulensis Dehnh. in Thailand, against Coptotermes formosanus Shiraki were investigated in contact and noncontact tests. The termiticidal mechanism was also examined. Antitermitic tests demonstrated that E. camaldulensis leaf oils were both contact toxicants and fumigants to C. formosanus with LC50 values ranging between 12.68 and 17.50 mg/g by the contact method, and between 12.65 and 17.50 mg/petri dish (100 cm3) by the noncontact method. p-Cymene and γ-terpinene were primarily responsible for the contact toxicity and 1,8-cineole was responsible for fumigation. From the investigation of termiticidal mechanism, E. camaldulensis leaf oils exhibited the inhibition of acetylcholinesterase activity and showed the common symptoms of a neurotoxic mode of action against C. formosanus. Part of this report was presented at the 58th Annual Meeting of the Japan Wood Research Society, Tsukuba, March 2008  相似文献   

8.
Pathogenicity of 13 strains of entomopathogenic fungi belonging to genera Paecilomyces, Tolypocladium, Beauveria, Metarhizium, and Lecanicillium (=Verticillium) was evaluated on fourth instar larvae of Thaumetopoea pityocampa (Schiff.) (Lep.: Thaumatopoeidae). Larvae were treated individually by dipping into conidial suspension with the concentration of 1.0 × 105 conidia ml−1. All the tested isolates resulted in various levels of mortality (16–100%), and eleven of them were able to grow and sporulate on dead larvae. Mortality caused by three isolates of P. fumosoroseus, one isolate of Beauveria bassiana and one isolate of Metarhizium anisopliae were significantly higher than that of the other treatments. Three isolates of P. fumosoroseus, one isolate of P. farinosus, and one isolate of M. anisopliae showed mycelial growth and sporulation on significantly more cadavers compared to other treatments. Dose–mortality test was conducted with P. fumosoroseus (isolate no: 2679), which appeared to be the most promising isolate among the tested fungi, by spraying five concentrations of its conidia (1.0 × 106, 1.5 × 106, 7.5 × 106, 1.0 × 107 and 1.5 × 107 conidia ml−1). The estimation of the LC50 (95% confidence limits) was 3.4 × 106 (9.3 × 105 − 6.9 × 106) conidia ml−1. This study showed that P. fumosoroseus (isolate no: 2679) could be a good candidate as a microbial control agent against T. pityocampa in forest environment.  相似文献   

9.
Glucose-6-phosphate dehydrogenase (G6PDH, EC 1.1.1.49) was purified from the leaves of 8-week-old Populus suaveolens cuttings. The enzyme activity in the absence and presence of reduced dithiothreitol (DTTred) was determined. The results show that the G6PDH activity is not inactivated by pre-incubation with DTTred, indicating that the purified enzyme probably presented in cytosol of P. suaveolens. The catalytic characteristics and kinetic parameters of cytosolic G6PDH purified from P. suaveolens cuttings were also studied. The results show that G6PDH is characterized by K m value of 360 μmol·L−1 for G6P and 16 μmol·L−1 for NADP, a pH range of 7.3-8.9, and the maximum activity around pH 8.2. The enzyme activity is inhibited by various metabolites such as NADPH, NADH, GTP, UTP, ATP, AMP, ADP, CoA, acetyl CoA, fructose-6-phosphate (F6P), erythrose-4-phosphate (E4P), ribose-5-phosphate (R5P) and 3-phosphoglycerate (3-PG) (all at 1 mmol·L−1 except for NADPH and NADH) to different extents. NADPH is the most effective inhibitor of enzyme activity, with an inhibition of 72.0%. The addition of metal ions such as MgCl2, CaCl2 and KCl (all 1.0 mmol·L−1) to the standard reaction mixture has no remarkable influence on the cytosolic G6PDH activity. However, CdCl2 (1.0 mmol·L−1) causes high inhibitory effect on the enzyme activity. To explore the role of G6PDH on the enhancement of freezing resistance induced by freezing acclimation, the changes in the cytosolic G6PDH activity and freezing resistance (expressed as LT50) of P. suaveolens cuttings during freezing acclimation at −20 °C were investigated. The results reveal that freezing acclimation decreases LT50 of cuttings, and increases the activity of cytosolic G6PDH compared with control ones, while 2 d of de-acclimation at 25 °C result in a decrease in cytosolic G6PDH activity, and caused an increase in LT50. Furthermore, the change in cytosolic G6PDH activity is found to be closely correlated to the degree of freezing resistance of cuttings during freezing acclimation. It is suggested that cytosolic G6PDH may be involved in the induction of freezing resistance of cuttings. [Supported by the Foundation of State-designated Base for Biology Researching and Teaching in Beijing Forestry University]  相似文献   

10.
A new withanolide identified by spectroscopic analysis as 12β-acetoxy-4-deoxy-5,6-deoxy-Δ5–withanolide D and Withanolide D, were isolated from the leaves of Acnistus arborescens. Cytotoxic activity of these two compounds against human tumor cell lines HT-29, MCF-7, MKN-45, HEp-2, HeLa, U-937 and two human normal fibroblast cultures, Fib04 and Fib05, were assessed. Withanolide D presented in vitro cytotoxic activity against tumor cell lines at the low micromolar range (LC50:1.0 to 1.69 µM) and showed a slightly lower activity against Fib04, suggesting moderated selectivity among tumoral and normal cells. No cytotoxic effect was observed for 12β-acetoxy-4-deoxy-5,6-deoxy-Δ5–withanolide D.  相似文献   

11.
Shin KS  Lee S  Cha BJ 《Fitoterapia》2007,78(7-8):585-586
The hexane extract of Nepenthes ventricosa x maxima leaf exhibited antifungal activity against Alternaria alternata, Aspergillus niger, Bipolaris oryzae, Fusarium oxysporum, Phytophthora capsici, Rhizoctonia solani, Rhizopus stolonifer var. stolonifer and Sclerotinia sclerotiorum.  相似文献   

12.
Baobab leaves form an important part of the local diet in Sahel countries and elsewhere in Africa. Existing leaf nutritional data and agroforestry performance information are based solely on Adansonia digitata L., the baobab of continental Africa. The introduction potential of Adansonia species from the center of diversity in Madagascar and from Australia remains untapped. To assess this potential, the mineral contents and B1 and B2 vitamin levels of dried baobab leaves were determined for five-year old trees of A. digitata, A. gibbosa (A. Cunn.) Guymer ex D. Baum, A. rubrostipa Jum. & H. Perrier (syn. A. fony Baill.), A. perrieri Capuron and A. za Baill. grown in an introduction trial in Mali. Nutritional data were evaluated against survival and vigor to identify promising germplasm. Leaf vitamin and crude protein contents were highest in the Madagascar species, especially A. rubrostipa (B1 88 mg 100 g−1, B2 187 mg 100 g−1, protein 20.7% dry weight). However, the local species far outperformed the introductions in survival, tree height, basal diameter and resistance to termites. We suggest grafting as a way of harnessing the vigor of well-adapted local baobab varieties to the superior nutritional profiles of A. rubrostipa and others. Cross-species grafting tests in Adansonia were successful, thus creating new agroforestry possibilities with different scion/rootstock combinations.  相似文献   

13.
The bioefficacies of essential oil and aromatized clay powder based on the mixture of clay and essential oil extracted from Clausena anisata were evaluated for their insecticidal activities and their effects on progeny production of Acanthoscelides obtectus. Contact toxicity assayed by coating on bean grains showed that these chemicals caused significant mortality of the test insect. Beetle mortality was dose dependant and after 2-day exposure the aromatized clay powder was more toxic (LD50 = 0.069 μl/g grain) than the pure essential oil (LD50 = 0.081 μl/g grain). There was, however, a highly significant loss of toxicity after 24 and 36 h following treatment with essential oil and aromatized powder, respectively. Both aromatized clay powder and pure essential oil considerably reduced the F1 progeny insect production. The essential oil evoked moderated repellent action and high fumigant toxicity (LC50 = 0.093 μl/cm3) against adults of A. obtectus. These results suggest that the clay powder could be used to stabilize the essential oil to increase its efficacy for use as an alternative to synthetic insecticides.  相似文献   

14.
We investigated the effects of two commercial diatomaceous earth based insecticides (DE), Protect-It® and SilicoSec®, the nano-structured silica product AL06, developed by the section for Urban Plant Ecophysiology at Humboldt University Berlin, and the monoterpenoids, eugenol, and cinnamaldehyde on two stored product pests, Callosobruchus maculatus and Sitophilus oryzae. Protect-It® was more effective than SilicoSec® against C. maculatus while the reverse was true for S. oryzae. Generally C. maculatus was more sensitive towards DE and silica treatment than S. oryzae. Mortality rate of both pest species increased when DE’s were applied to food commodities previously treated with a monoterpenoid. In admixture experiments, the toxicity of SilicoSec® + cinnamaldehyde (LD50 = 42.73 ppm), SilicoSec® + eugenol (LD50 = 24.30 ppm), and Protect-It® + eugenol (LD50 = 2.60 ppm) was increased over DE alone against S. oryzae. Both substances showed a synergistic effect considering their co-toxicity coefficient relative to the LD50-value. In contrast, we could not find any synergistic effects in experiments with C. maculatus. Here only Protect-It® + cinnamaldehyde (LD50 = 20.84 ppm) showed an additive effect while all other combinations of monoterpenoid and DE indicated antagonistic effects. In addition to contact insecticidal effects both monoterpenoids showed a strong fumigant action. The presented results indicate that the natural product DE has great potential to replace synthetic pesticides commonly used in stored product pest management. Efficacy of DE can be improved by adding certain monoterpenoids against certain insect pests.  相似文献   

15.
A field experiment was performed in eastern Kenya to estimate N2 fixation by Sesbania sesban over an 18-month period using the 15N dilution method. The influence of three reference species, Senna spectabilis, Eucalyptus saligna and Grevillea robusta, on the estimates of N2 fixation was also assessed. Percentage Ndfa (nitrogen derived from the atmosphere) was calculated based on foliar atom excess (FAE), above-ground atom excess (AAE) or whole tree atom excess (WAE) data. The differences in atom% 15N excess values between species and plant parts are presented and discussed. We recommend the use of several reference species for estimating %Ndfa and that the different results obtained should be carefully considered in relation to the issues being addressed. In this study, Senna was the most suitable of the three reference species because its N uptake pattern and phenology were very similar to those of Sesbania. When well established, the amount of N fixed by Sesbania accounts for more than 80% of its total N content, according to FAE-based estimates. We estimated the Ndfa by Sesbania after 18 months to between 500 and 600 kg ha−1 , depending on whether FAE, AAE or WAE data were used and on the choice of reference species. The substantial accumulation of N in planted Sesbania highlighted its potential to increase the sustainability of crop production on N-limited soils. We consider the 15N dilution method to be appropriate for quantifying N2 fixation in improved fallows in studies, similar to this one, of young trees with high N2-fixing ability.  相似文献   

16.
Rhizobia were isolated from Albizia lebbek (L) Benth. seed-lings collected from six different places, tested against the nodulation test and inoculated into 45 day old Albizia lebbek seedlings in steri...  相似文献   

17.
Antifungal activities of seven compounds, taxinine (1), paclitaxel (2), phenylisoserine methyl ester (3), sciadopitysin (4), ginkgetin (5), isorhamnetin (6), and quercetin (7), isolated from the leaves of kyaraboku, Taxus cuspidata var. nana, against five plant pathogenic fungi, Gibberella fujikuroi, Cladosporium cucumeninum, Fusarium oxysporum, Colletotrichum fragariae, and Corynespora cassiicola, were investigated for utilization of extractives from trees of the genus Taxus. Also, the amounts of compounds 2 and 3 on the leaf surface was measured in relation to the antifungal activities of compounds. Taxinine (1) showed antifungal activity against G. fujikuroi, C. cucumeninum, F. oxysporum, and C. cassiicola. The minimum inhibitory concentration of taxinine for the four fungi was 0.4mol. In addition, from the results of antifungal tests, it may be concluded that paclitaxel on the leaves and stem of T. cuspidata var. nana does not play an important role as an antifungicide in the resistance of trees to plant pathogenic fungal attack.  相似文献   

18.
Bioassays were performed to determine the antifungal and insecticidal activity of clove essential oil (EO), several botanical compounds (eugenol, carvacrol, allylisothiocyanate (AITC) and ethyl formate (EtF)) against mycotoxigenic fungi (Aspergillus westerdijkiae and Fusarium graminearum) and the rice weevil, Sitophilus oryzae. Antifungal activity was quantified by measuring conidia germination inhibition and mycelial growth inhibition zone to determine the minimum inhibitory concentration (MIC). Mortality of insects was determined through either contact toxicity assay (impregnated filter paper) or fumigation toxicity assay (airtight exposure chamber). A four-parameter logistic regression of fungi inhibitory growth rate to the dose of tested substances, either by the agar diffusion assay or the micro-atmosphere test, showed that AITC had antifungal and sporicide activity. The concentration at MIC for A. westerdijkiae and F. graminearum was 24.2 and 19.8???l?l?1, respectively, whereas clove essential oil (EO) was 755 and 352???l?l?1 after 72?h incubation period. Bioassays with S. oryzae showed that clove EO contact insecticidal activity was similar to pure eugenol and carvacrol: LD90s were 366, 385 and 442???l?dm?2, respectively. The fumigation insecticidal activity of AITC was LC95?=?10.8???l?l?1. For EtF and clove EO, only the LC50 could be accurately determined after 24?h exposure time which was observed at 41 and 210???l?l?1, respectively (vs. 6.4???l?l?1 for AITC LC50). The combined antifungal activity on mycotoxigenic seed-borne fungi and insecticidal activity against the rice weevil demonstrated that AITC in vapour phase may be a promising active substance for the preservation grain stored in unsafe conditions with a risk of fungal growth.  相似文献   

19.
The aphid transmissibility and within-plant movement of two PVY isolates belonging to PVYO and PVYN strains were studied. Potato plants were infected by Myzus persicae either 1 week after emergence or 30 or 45 days after emergence. Infected leaves, petioles of infected leaves, and different segments of the stems of plants infected 1 week after emergence were ELISA-tested 7, 11 and 14 days after infection. Segments of the plants infected 30 or 45 days after emergence were ELISA tested 30 days after infection. Normalised ELISA values were used for statistical analyses. Virus infection of progeny tubers was assessed by post-harvest inspection. The ability of 15 aphid species to transmit the virus isolates was also examined. There was no difference in the aphid transmissibility of the two isolates 7 or 11 days after exposure to M. persicae. However, normalised ELISA values were significantly affected by both isolate and sampling date 11 and 14 days after M. persicae transmission. The level of infection of different stem segments was significantly affected by both isolate and growth stage of the plant at infection. The proportions of infected leaves, stem segments and progeny tubers were all significantly higher for PVYN than for PVYO. PVYN was more effectively transmitted by a number of different aphid species than was PVYO. Newly described vectors of PVYN include Schizaphis graminum, Aphis fabae cirsiacanthoides, Aphis spiraecola, Myzus ligustri, Aphis fabae, Aphis spiraephaga, Myzus cerasi, Macrosiphum rosae, Diuraphis noxia, Aphis pomi and Rhopalosiphum padi, while those of PVYO include Aphis fabae cirsiacanthoides, Myzus cerasi and Myzus ligustri.  相似文献   

20.
间伐对杉木人工林土壤酶活性及微生物的影响   总被引：1，自引：0，他引：1       下载免费PDF全文
[目的]研究间伐对杉木人工林土壤微生物数量、酶活性及关系的影响,试图了解不同间伐强度作用下土壤恢复的过程和机制,为人工林经营提供理论依据。[方法]以18年生杉木人工林为研究对象,采用随机区组试验设计,分析4种间伐强度TS0(未间伐(0.0%),1 800株·hm-2)、TS1(轻度(16.7%),1 500株·hm-2)、TS2(中度(33.3%),1 200株·hm-2)和TS3(重度(50.0%),900株·hm-2)下杉木人工林土壤微生物数量及土壤酶活性特点,探讨土壤微生物数量与酶活性的相关性。[结果]表明:间伐3年后,林下土壤层酶活性和微生物数量显著提高,不同土层间土壤微生物数量和酶活性均差异显著;间伐显著提高了土壤过氧化氢酶、碱性磷酸酶、脲酶和蔗糖酶的活性,除过氧化氢酶(15 30、30 45 cm)、碱性磷酸酶(0 15、30 45 cm)以及脲酶(30 45 cm)以TS3处理的酶活性最高外,其他酶活性在各土层和不同间伐强度下均以TS2处理的酶活性最高;土壤各层微生物以细菌数量最多,其次是放线菌,硝化细菌最少,且TS2处理的微生物数量最多。土壤过氧化氢酶和脲酶活性均与细菌、真菌和硝化细菌数量呈极显著正相关,与放线菌数量呈极显著负相关,氨化细菌数量与过氧化氢酶活性呈负相关,而与脲酶活性呈正相关;碱性磷酸酶活性与细菌、真菌和硝化细菌数量呈正相关,与氨化细菌数量呈极显著负相关,与放线菌数量呈负相关;蔗糖酶活性与细菌、真菌和氨化细菌数量呈极显著正相关,与硝化细菌数量呈正相关,与放线菌数量呈负相关。[结论]间伐改善了林分环境、光照、温度以及林下植被的发育,提高了林下土壤酶活性并增加了微生物数量。间伐3年后的综合表现表明,中度间伐最利于杉木人工中、近熟林阶段的经营,对于改善土壤性质较好。  相似文献   

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