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1.
Abhishek Tripathi Neeta Sharma Vinay Sharma 《World journal of microbiology & biotechnology》2009,25(3):503-512
Hyptis
suaveolens L. (Poit.) essential oil was tested in vitro on the growth and morphogenesis of Fusarium oxysporum f.sp. gladioli (Massey) Snyder & Hansen, which causes Fusarium corm rot and yellows in various susceptible cultivars of gladiolus. The fungitoxicity of the oil was measured by percentage radial growth inhibition using the poisoned food technique (PF)
and volatile activity assay (VA). The mycelial growth of the test fungus was completely inhibited at 0.998 and 0.748 μg ml−1 concentration of oil in PF and VA, respectively. Essential oil was found to be fungicidal in nature at 1.247 and 0.998 μg ml−1 concentration of oil in PF and VA, respectively. Determination of conidial germination in the presence of oil was also carried
out and it was found that the oil exhibited 100% inhibition of conidial germination at 0.450 μg ml−1 concentration. The effect of essential oil on the yield of mycelial weight was observed and it was found that at 0.873 μg ml−1 concentration no mycelium was recorded and 100% inhibition was observed. The fungitoxicity of oil did not change even on
exposure to 100°C temperature or to autoclaving, and the oil also retained its fungicidal nature even after storage of 24 months.
The main changes observed under light microscopy after oil treatment were a decrease and loss of conidiation and anomalies
in the hyphae such as a decrease in the diameter of hyphae and granulation of cytoplasm. The treatment of the oil also showed
highly reduced cytoplasm in the hyphae, showing clear retraction of the cytoplasm from the hyphae and ultimately in some areas
hyphae without cytoplasm were also found. GC-MS studies of the essential oil revealed that the oil consisted of 24 compounds
with 1,8-cineole as major component accounting for 44.4% of the total constituents. 相似文献
2.
Yun Teng Qian Yang Zhiyi Yu Guoping Zhou Qiu Sun Hong Jin Taiping Hou 《World journal of microbiology & biotechnology》2010,26(1):9-14
The qualitative and quantitive determination of chemical components of leaf essential oil of Spiraea alpina Pall. with Microwave-assisted Hydrodistillation is carried out by gas chromatography-mass spectrometry. About 69 compounds
have been identified from the leaf oil, accounting for 79.39% of the total. The in vitro antifungal activity of S. alpina essential oil was studied against eight test phytopathogenic bacteria and fungi namely Xanthomonas oryzae pv. oryzae, Xanthomonas campestris pv. citri, Ralstonia solanacearum, Erwinia carotovora subsp. carotovora and Rhizoctonia solani, Fusarium graminerum, Pyricularia oryzea, Exserohilum turcicum by the agar Well Diffusion Method and Poisoned Food Technique, respectively. In the case, R. solanacearum was found to be sensitive to S. alpina oil at a concentration of 10 μl·well−1 and the inhibition zone diameter was found to be 10.7 mm. Concentration- and time-dependent fungitoxicity was recorded from
125 to 1,000 μg·ml−1 concentration. About 125 μg·ml−1 of leaf oil solution partially inhibited the mycelial growth of R. solani to the same extent as 50 μg·ml−1 of miconazole. The oil also affected the mycelial growth of F. graminerum and E. turcicum in a dose-dependent manner but had a weak effect on the growth of P. oryzea. 相似文献
3.
Palmero Llamas D de Cara Gonzalez M Iglesias Gonzalez C Ruíz Lopez G Tello Marquina JC 《Journal of industrial microbiology & biotechnology》2008,35(11):1411-1418
Germination of macroconidia and/or microconidia of 24 strains of Fusarium solani, F. chlamydosporum, F. culmorum, F. equiseti, F. verticillioides, F. sambucinum, F. oxysporum and F. proliferatum isolated from fluvial channels and sea beds of the south-eastern coast of Spain, and three control strains (F. oxysporum isolated from affected cultures) was studied in distilled water in response to a range of water potentials adjusted with
NaCl. (0, −13.79, −41.79, −70.37, −99.56 and −144.54 bars). The viability (UFC/ml) of suspensions was also tested in three
time periods (0, 24 and 48 h). Conidia always germinated in distilled water. The pattern of conidial germination observed
of F. verticilloides, F. oxysporum, F. proliferatum, F. chlamydosporum and F. culmorum was similar. A great diminution of spore germination was found in −13.79 bars solutions. Spore germination percentage for
F. solani isolates was maximal at 48 h and −13.79 bars with 21.33% spore germination, 16% higher than germination in distilled water.
F. equiseti shows the maximum germination percentage in −144.54 bars solution in 24 h time with 12.36% germination. This results did
not agree with those obtained in the viability test were maximum germination was found in distilled water. The viability analysis
showed the great capacity of F. verticilloides strains to form viable colonies, even in such extreme conditions as −144.54 bars after 24 h F. proliferatum colony formation was prevented in the range of −70.37 bars. These results show the clear affectation of water potential to
conidia germination of Fusaria. The ability of certain species of Fusarium to develop a saprophytic life in the salt water of the Mediterranean Sea could be certain. Successful germination, even under
high salty media conditions, suggests that Fusarium spp. could have a competitive advantage over other soil fungi in crops irrigated with saline water. In the specific case
of F. solani, water potential of −13.79 bars affected germination positively. It could indicate that F. solani has an special physiological mechanism of survival in low water potential environments. 相似文献
4.
Hari Datta Bhattarai Viswanadh Sarma Ganti Babita Paudel Yoo Kyung Lee Hong Kum Lee Yong-Ki Hong Hyun Woung Shin 《World journal of microbiology & biotechnology》2007,23(2):243-249
Two compounds, 2-hydroxymyristic acid (HMA) and cis-9-oleic acid (COA), were isolated from a chloroform extract of the marine
bacterium, Shewanella oneidensis SCH0402. In a spectrophotometer-based chemotaxis assay, HMA completely eliminated the optical density (OD) of Alteromonas marina SCH0401 and Bacillus atrophaeus SCH0408, motile, fouling bacteria, at 100 and 1000 μg ml−1, respectively. COA similarly decreased the OD of A. marina and B. atrophaeus by 100% at 1000 μg ml−1. The commercially available, highly toxic anti-fouling compound, tributyltin oxide (TBTO) never reduced the OD of the target
bacteria by 100% even at higher concentration. Instead, all the test bacterial cells were killed at higher than 1000 μg ml−1 of concentration. Both HMA and COA inhibited germination of Ulva pertusa spores completely at 10 and 100 μg ml−1, respectively, while TBTO inhibited germination at 0.01 μg ml−1. However, in field assays, both HMA and COA showed anti-fouling activities as potent as TBTO against a wide range of fouling
organisms, including micro- and macro-algae, barnacles, and mussels. The average fouling coverage on the surface of the control
panel was 93 ± 6% after 1.5 years but no fouling was observed on the surface of the test panel onto which each compound was
applied separately. Thus, bacterial repellent compounds can be used as substitutes for potent toxic anti-fouling compounds,
resulting in higher standards of environmental safety without loss of anti-fouling performance. 相似文献
5.
Z. Q. Chang B. C. Oh M. H. Rhee J. C. Kim S. P. Lee S. C. Park 《World journal of microbiology & biotechnology》2007,23(5):723-727
Polysaccharides isolated from Phellinus baumii (PBP) significantly enhanced both lipopolysaccharide (LPS)-induced B lymphocyte proliferation and concanavalin A (Con A)-induced
T lymphocyte proliferation. However, PBP (12.5–100 μg ml−1) significantly suppressed the LPS-induced nitric oxide (NO) production in RAW264.7 cells in a concentration-dependent manner.
The maximal inhibition of PBP on NO production was 37.5% at 100 μg ml−1. These results provide useful in vitro information to explain the immunostimulating activity and anti-inflammatory activity
of PBP. 相似文献
6.
An endophytic Xylaria sp., having broad antimicrobial activity, was isolated and characterized from Ginkgo biloba L. From the culture extracts of this fungus, a bioactive compound P3 was isolated by bioactivity-guided fractionation and
identified as 7-amino-4-methylcoumarin by nuclear magnetic resonance, infrared, and mass spectrometry spectral data. The compound
showed strong antibacterial and antifungal activities in vitro against Staphylococcus aureus [minimal inhibitory concentrations (MIC) 16 μg·ml−1], Escherichia coli (MIC, 10 μg·ml−1), Salmonella typhia (MIC, 20 μg·ml−1), Salmonella typhimurium (MIC, 15 μg·ml−1), Salmonella enteritidis (MIC, 8.5 μg·ml−1), Aeromonas hydrophila (MIC, 4 μg·ml−1), Yersinia sp. (MIC, 12.5 μg·ml−1), Vibrio anguillarum (MIC, 25 μg·ml−1), Shigella sp. (MIC, 6.3 μg·ml−1), Vibrio parahaemolyticus (MIC, 12.5 μg·ml−1), Candida albicans (MIC, 15 μg·ml−1), Penicillium expansum (MIC, 40 μg·ml−1), and Aspergillus niger (MIC, 25 μg·ml−1). This is the first report of 7-amino-4-methylcoumarin in fungus and of the antimicrobial activity of this metabolite. The
obtained results provide promising baseline information for the potential use of this unusual endophytic fungus and its components
in the control of food spoilage and food-borne diseases. 相似文献
7.
S. K. Singh B. K. Sarma J. S. Srivastava U. P. Singh A. B. Ray 《Folia microbiologica》1999,44(5):510-512
A plant quaternary alkaloid Δ3-alstovenine inhibited the spore germination of most of the fungi tested at concentration of 250–1000 mg/L. Saprophytic and
biotrophic fungi were equally sensitive to the alkaloid.Cercospora sp. was the most sensitive as 100% inhibition of spore germination was observed at 250 mg/L.Alternaria species,Curvularia species andFusarium udum were not affected even at 1000 mg/L. 相似文献
8.
Vivek K. Bajpai Hak Ryul Kim Ching Tsang Hou Sun Chul Kang 《Journal of industrial microbiology & biotechnology》2009,36(5):695-704
Microbial modification of polyunsaturated fatty acids can often lead to special changes in their structure and in biological
potential. Therefore, the aim of this study was to develop potential antifungal agents through the microbial conversion of
docosahexaenoic acid (DHA). Bioconverted oil extract of docosahexaenoic acid (bDHA), obtained from the microbial conversion
of docosahexaenoic acid (DHA) by Pseudomonas aeruginosa PR3, was assessed for its in vitro and in vivo antifungal potential. Mycelial growth inhibition of test plant pathogens,
such as Botrytis cinerea, Colletotrichum capsici, Fusarium oxysporum, Fusarium solani, Phytophthora capsici, Rhizoctonia solani and Sclerotinia sclerotiorum, was measured in vitro. bDHA (5 μl disc−1) inhibited 55.30–65.90% fungal mycelium radial growth of all the tested plant pathogens. Minimum inhibitory concentrations
(MICs) of bDHA against the tested plant pathogens were found in the range of 125–500 μg ml−1. Also, bDHA had a strong detrimental effect on spore germination for all the tested plant pathogens. Further, three plant
pathogenic fungi, namely C. capsici, F. oxysporum and P. capsici, were subjected to an in vivo antifungal screening. bDHA at higher concentrations revealed a promising antifungal effect
in vivo as compared to the positive control oligochitosan. Furthermore, elaborative study of GC-MS analysis was conducted
on bioconverted oil extract of DHA to identify the transformation products present in bDHA. The results of this study indicate
that the oil extract of bDHA has potential value of industrial significance to control plant pathogenic fungi. 相似文献
9.
Militello M Settanni L Aleo A Mammina C Moschetti G Giammanco GM Blàzquez MA Carrubba A 《Current microbiology》2011,62(4):1274-1281
This study was undertaken to characterize the essential oil (EO) of Artemisia arborescens growing wild in Sicily. EO, extracted by steam distillation, was examined for its chemical composition and for its capability
to inhibit some food-borne pathogen bacteria. A total of 43 compounds (13 monoterpene hydrocarbons, 14 oxygenated monoterpenes,
10 sesquiterpene hydrocarbons, three oxygenated sesquiterpenes and less amount of other three compounds), which account 93.73%
of the total oil, were identified by gas chromatography and gas chromatography–mass spectrometry. Oxygenated monoterpenes
(57.32%) constituted the main fraction, with β-thujone as the main compound (45.04%), followed by the sesquiterpene hydrocarbon
chamazulene (22.71%). Undiluted EO showed a large inhibition spectrum against strains of Listeria monocytogenes (34 out of 44), whilst it was ineffective against enterobacteria and salmonellas. The minimum inhibition concentration (MIC)
was evaluated for the two most sensitive strains (L. monocytogenes 186 and 7BO) at two cellular concentrations (106 and 107 CFU ml−1). The lowest MIC (0.625 μl ml−1, dilution of oil with acetone) was found for strain L. monocytogenes 186 at 106 CFU ml−1. 相似文献
10.
Lindane or γ- hexachlorocyclohexane (γ-HCH) is a chlorinated pesticide and its toxic effects on biota necessitate its removal.
Microbial degradation is an important process for pesticide bioremediation and the role of soil fungi in recycling of organic
matter prompted us to study the biodegradation of lindane using fungi. This study aims at enrichment, isolation and screening
of soil fungi capable of metabolizing lindane. Two Fusarium species (F. poae and F. solani) isolated from the pesticide contaminated soil showed better growth on the plates supplemented with lindane as a sole carbon
source, when compared with the growth performance of other fungal isolates from the same contaminated soil. However, ANOVA
revealed a significant difference in fungal biomass production in both F. poae (F = 22.02; N = 15; P < 0.001) and F. solani (F = 268.75; N = 15; P < 0.001) across different lindane concentrations (0–600 μg ml−1). Growth of both Fusarium sp. was maximum at a lindane concentration of 100 μg ml−1, while minimum at 600 μg ml−1 concentrations. Results on the time dependent release of chlorine by the Fusarium strains in the presence of various concentration of lindane showed the highest mineralization of the pesticide on 10th day
of incubation. Time dependent variations in the release of chlorine from 1st to 10th day by both the selected fungal strains
were found to be statistically significant. A significant positive relationship exists between fungal biomass increase and
chlorine release existed for both F. solani (R2 = 0.960) and F. poae (R2 = 0.628). The results of gas chromatograph analysis of γ- HCH confirmed the biodegradation and utilization of γ- HCH
by F. poae and F. solani. The data on lindane degradation by the two fungal strains demonstrated that the biodegradation of lindane by F. solani (59.4%) was slightly higher than that by the F. poae (56.7%). 相似文献
11.
DC Sabaté MJ Gonzaléz MP Porrini MJ Eguaras MC Audisio JM Marioli 《World journal of microbiology & biotechnology》2012,28(4):1415-1422
The aim of this work was to determine the in vitro effect of the mixture between the lipopeptide surfactin, synthesized by
Bacillus subtilis C4 (strain isolated from honey) and the most active vegetal extract from Achyrocline satureioides, a traditional medicinal plant, on local strains of Paenibacillus larvae, the agent of American Foulbrood in honeybees. Five P. larvae strains isolated in Córdoba, Argentina, were phenotypically characterized. These and 12 other P. larvae strains from different regions of Argentina were analysed. The antimicrobial activities of the essential oil, hexane (HE)
and benzene extracts from A. satureioides were assessed against P. larvae and the HE showed the highest anti-P. larvae activity. A combination of the biosurfactant surfactin, produced by B. subtilis C4, and the HE of A. satureioides revealed a synergistic action on P. larvae. The effective surfactin concentration in the mixture decreased from 32 to 1 μg ml−1 and the HE concentration from 32 to 4 μg ml−1, values similar or equal to minimal inhibitory concentrations observed for oxytetracycline. The fractional inhibitory concentration
index confirmed synergism in 4 strains and partial synergism in one strain. The combination of surfactin synthesized by B. subtilis C4 and the HE from A. satureioides could be a natural alternative to help beekeepers to combat the American foulbrood agent P. larvae. 相似文献
12.
Santiago IF Alves TM Rabello A Sales Junior PA Romanha AJ Zani CL Rosa CA Rosa LH 《Extremophiles : life under extreme conditions》2012,16(1):95-103
A total of 564 isolates of endophytic fungi were recovered from the plants Deschampsia antarctica and Colobanthus quitensis collected from Antarctica. The isolates were screened against parasites Leishmania amazonensis and Trypanosoma cruzi and against the human tumour cell lines. Of the 313 fungal isolates obtained from D. antarctica and 251 from C. quitensis, 25 displayed biological activity. Nineteen extracts displayed leishmanicidal activity, and six inhibited the growth of at
least one tumour cell line. These fungi belong to 19 taxa of the genera Alternaria, Antarctomyces, Cadophora, Davidiella, Helgardia, Herpotrichia, Microdochium, Oculimacula, Phaeosphaeria and one unidentified fungus. Extracts of 12 fungal isolates inhibited the proliferation of L. amazonesis at a low IC50 of between 0.2 and 12.5 μg ml−1. The fungus Phaeosphaeria herpotrichoides displayed only leishmanicidal activity with an IC50 of 0.2 μg ml−1, which is equivalent to the inhibitory value of amphotericin B. The extract of Microdochium phragmitis displayed specific cytotoxic activity against the UACC-62 cell line with an IC50 value of 12.5 μg ml−1. Our results indicate that the unique angiosperms living in Antarctica shelter an interesting bioactive fungal community
that is able to produce antiprotozoal and antitumoral molecules. These molecules may be used to develop new leishmanicidal
and anticancer drugs. 相似文献
13.
Buatong Jirayu Phongpaichit Souwalak Rukachaisirikul Vatcharin Sakayaroj Jariya 《World journal of microbiology & biotechnology》2011,27(12):3005-3008
The aim of this work was to select endophytic fungi from mangrove plants that produced antimicrobial substances. Minimal inhibitory
concentrations (MIC) and minimal bactericidal concentrations (MBC) or minimal fungicidal concentrations (MFC) of crude extracts
from 150 isolates were determined against potential human pathogens by a colorimetric microdilution method. Ninety-two isolates
(61.3%) produced inhibitory compounds. Most of the extracts (28–32%) inhibited Staphylococcus aureus (MIC/MBC 4–200/64–200 μg ml−1). Only two extracts inhibited Pseudomonas aeruginosa (MIC/MBC 200/>200 μg ml−1). 25.5 and 11.7% inhibited Microsporum gypseum and Cryptococcus neoformans (MIC/MFC 4–200/8–200 μg ml−1 and 8–200/8–200 μg ml−1, respectively), while 7.5% were active against Candida albicans (MIC/MFC 32–200/32–200 μg ml−1). None of the extracts inhibited Escherichia coli. The most active fungal extracts were from six genera, Acremonium, Diaporthe, Hypoxylon, Pestalotiopsis, Phomopsis, and Xylaria as identified using morphological and molecular methods. Phomopsis sp. MA194 (GU592007, GU592018) isolated from Rhizophora apiculata showed the broadest antimicrobial spectrum with low MIC values of 8–32 μg ml−1against Gram-positive bacteria, yeasts and M. gypseum. It was concluded that endophytic fungi from mangrove plants are diverse, many produce compounds with antimicrobial activity
and could be suitable sources of new antimicrobial natural products. 相似文献
14.
Saul Tlecuitl-Beristain Gustavo Viniegra-González Gerardo Díaz-Godínez Octavio Loera 《Mycopathologia》2010,169(5):387-394
Rice and oat flours were analyzed as media for the production of conidia by M. anisopliae var. lepidiotum. The presence of peptone increased conidia yield regardless of the substrate used; however, the highest yield was achieved
on oat flour media. The effect of oxygen on conidia production using oat-peptone medium was also studied at two levels: Normal
atmosphere (21% O2) and Oxygen-rich pulses (26% O2). Maximum conidia production (4.25 × 107 conidia cm−2) was achieved using 26% O2 pulses after 156 h of culture, which was higher than 100% relative to conidial levels under normal atmosphere. Conidia yield
per gram of biomass was 2.6 times higher with 26% O2 (1.12 × 107 conidia mg−1). Conidia quality parameters, such as germination and hydrophobicity, did not show significant differences (P < 0.05) between those treatments. Bioassays parameters, using Tenebrio molitor adults, were analyzed for conidia obtained in both atmospheres and data were fitted to an exponential model. The specific
mortality rates were 2.22 and 1.26 days−1, whereas lethal times for 50% mortality were 3.90 and 4.31 days, for 26% O2 pulses and 21% O2 atmosphere, respectively. These results are relevant for production processes since an oxygen increase allowed superior levels
of conidia by M. anisopliae without altering quality parameters and virulence toward Tenebrio molitor adults. 相似文献
15.
In the first part of this study, four isolates of the fungus Beauveria bassiana (Bals.) Vuillemin (LPP1, LPP2, CG05 and CG24) and one isolate of Metarhizium anisopliae (Metsch.) Sorokin (CG46) were tested against adult foragers of Atta sexdens rubropilosa. Ants were allowed to walk on filter paper discs, inside Petri dishes, previously impregnated with 1 ml of a conidia suspension
(2 × 107 conidia ml−1), maintained at 80% RH and 26°C for 24 h and subsequently, transferred to sterile Petri dishes, maintained at 23°C, 80% RH,
24 h dark. The mean values of LT50 for LPP2, LPP1, CG46, CG24 and CG05 were 3.5, 3.7, 3.8, 4.2 and 4.4 days, respectively. Control insects for all tests in
this study showed less than 10% mortality. Experiments were carried out to test the toxicity of imidacloprid (IMI) to A. sexdens rubropilosa. Mortality was evaluated 10 days following a 24 h exposure to the insecticide. Percent mortality caused by 500, 200, 100
and 10 ppm IMI was 77.8, 56.7, 45.5 and 5.5 respectively. Insects treated with 10 ppm IMI were observed to have reduced locomotor
activity 24 h after exposure to the insecticide. The LC50 of IMI was 154.3 ppm. Subsequent tests were carried out to evaluate the combination of a sub-lethal dose of IMI (10 ppm)
and infection by CG24 (1 × 107 conidia ml−1). Mortality due to fungal infection alone was 43.3%. Mortality of insects treated with IMI followed by exposure to the fungus
was 64.3%. These results indicate that IMI significantly increases the susceptibility of ants to infection by B. bassiana CG24. 相似文献
16.
Helen Elizabeth Roy Peter M. J. Brown Peter Rothery Remy L. Ware Michael E. N. Majerus 《BioControl》2008,53(1):265-276
Harmonia axyridis is a predatory coccinellid, native to central and eastern Asia. It has been available in many countries for use as a biological
control agent of pest aphids and scale insects. In many of these countries, including the USA, H. axyridis has established. It is now considered an invasive alien species for a number of reasons, including its impact on functional
biodiversity. Beauveria bassiana is known to be a natural mortality agent of overwintering coccinellids and is a potential candidate for the biological control
of H. axyridis. In this paper we compare the susceptibility of three species of coccinellid, H. axyridis (cultures derived from Japan and UK), Coccinella septempunctata and Adalia bipunctata to infection by B. bassiana (commercial strain GHA) after exposure at three doses (105, 107, 109 conidia ml−1). The two subpopulations of H. axyridis (Japan and UK) were more resistant to B. bassiana infection than either A. bipunctata or C. septempunctata. This is exemplified by the median lethal doses at 10 days post-inoculation (LD50) of 106.2, 106.0, 108.3, 109.6 conidia ml−1 for A. bipunctata, C. septempunctata, H. axyridis (Japan) and H. axyridis (UK), respectively. Only doses of 109 conidia ml−1 resulted in mortality of H. axyridis, in contrast, 80% of C. septempunctata and 70% of A. bipunctata exposed to 107 conidia ml−1 of B. bassiana succumbed to infection. The fecundity (cumulative mean egg production over 10 days) of A. bipunctata and H. axyridis (UK) was also assessed. The fecundity of C. septempunctata could not be assessed because this species requires diapause prior to the onset of reproduction and these studies were on
beetles that had recently eclosed (2–8 weeks). Harmonia axyridis (Japan) produced no eggs in most treatments including the control and so was excluded from analysis. High dose (109 conidia ml−1) inoculation reduced the fecundity of A. bipunctata to zero but egg production was similar for individuals inoculated with doses of 105, 107 conidia ml−1 and control individuals. In contrast, all doses of B. basssiana reduced H. axyridis (UK) egg production dramatically. We discuss these results in relation to the potential for control of H. axyridis using B. bassiana. 相似文献
17.
Luna JM Rufino RD Sarubbo LA Rodrigues LR Teixeira JA de Campos-Takaki GM 《Current microbiology》2011,62(5):1527-1534
Different groups of biosurfactants exhibit diverse properties and display a variety of physiological functions in producer
microorganisms; these include enhancing the solubility of hydrophobic/water-insoluble compound, heave metal binding, bacterial
pathogenesis, cell adhesion and aggregation, quorum sensing and biofilm formation. Candida sphaerica was grown in a low cost medium, consisting of distilled water supplemented with 9% refinery residue of soybean oil and 9%
corn steep liquor, for 144 h at 28°C and 150 rpm. The cell-free supernatant obtained at the end of the experiments was submitted
to extraction, and afterward the biosurfactant was isolated using methanol with a yield of 9 g l−1. The critical micelle concentration of the biosurfactant was found to be 0.25 mg ml−1 with a surface tension of 25 mN m−1. Several concentrations of the biosurfactant (0.625–10 mg ml−1) were used to evaluate its antimicrobial and antiadhesive activities against a variety of microorganisms. The biosurfactant
showed antimicrobial activity against Streptococcus oralis (68%), Candida albicans (57%), and Staphylococcus epidermidis(57.6%) for the highest concentration tested. Furthermore, the biosurfactant at a concentration of 10 mg ml−1 inhibited the adhesion between 80 and 92% of Pseudomonas aeruginosa, Streptococcus agalactiae, Streptococcus sanguis12. Inhibition of adhesion with percentages near 100% occurred for the higher concentrations of biosurfactant used. Results gathered
in this study point to a potential use of the biosurfactant in biomedical applications. 相似文献
18.
Degradative ability of 2,4,6-tribromophenol by saprophytic fungi Trametes versicolor and Agaricus augustus isolated from chilean forestry 总被引:1,自引:1,他引:0
César Donoso José Becerra Miguel Martínez Norberto Garrido Mario Silva 《World journal of microbiology & biotechnology》2008,24(7):961-968
Trametes versicolor and Agaricus augustus, with a maximum tolerable concentration (MTC) of 80 μg ml−1 tribromophenol (TBP), were selected to evaluate TBP biodegradation capacity. These fungi were capable of decreased TBP concentrations
and A. augustus was also capable of biotransforming TBP to tribromoanisole (TBA). Peroxidase and laccase activities were observed in the
T. versicolor supernatant but not in that of A. augustus. These tolerance levels could be due to either lignolytic enzymes that degrade TBP or the ability of the fungi to biotransform
TBP to tribromoanisole, respectively. The sustained ability of T. versicolor to degrade TBP (total of 40 μg ml−1) in the presence of an additional carbon source suggests that it may have potential applications in the degradation of forestry
industry waste. 相似文献
19.
Elíades Lorena Cabello Marta Voget Claudio Galarza Betina Saparrat Mario 《World journal of microbiology & biotechnology》2010,26(11):2105-2111
A screening was carried out on 69 fungal strains isolated from alkaline-calcareous, neutral and alkaline-sodic soils, as well
as from their associated plant material, to determine their ability to grow at alkaline pH. A total of 32 fungi were selected
for their ability to produce alkaline keratinase activity in submerged shaken cultures supplemented with soybean meal (SM)
and tryptone and on cow hair (CH) under solid state fermentation conditions. Although several fungal strains produced keratinolytic
activity on both SM and CH, they differed in the levels detected. Among them, Aspergillus niger, Cladosporium cladosporioides, Metarrhizium anisopliae, Neurospora tetrasperma and Westerdikella dispersa were the best producers, with levels higher than 1.2 U ml−1. Different fungal species are here reported for the first time for their ability to produce keratinolytic activity at alkaline
pH. 相似文献
20.
Rates of net photosynthesis (P
N) and transpiration (E), and leaf temperature (TL) of maintenance leaves of tea under plucking were affected by photosynthetic photon flux densities (PPFD) of 200–2 200 μmol
m−2 s−1. P
N gradually increased with the increase of PPFD from 200 to 1 200 μmol m−2 s−1 and thereafter sharply declined. Maximum P
N was 13.95 μmol m−2 s−1 at 1 200 μmol m−2 s−1 PPFD. There was no significant variation of P
N among PPFD at 1 400–1 800 μmol m−2 s−1. Significant drop of P
N occurred at 2 000 μmol m−2 s−1. PPFD at 2 200 μmol m−2 s−1 reduced photosynthesis to 6.92 μmol m−2 s−1. PPFD had a strong correlation with TL and E. Both TL and E linearly increased from 200 to 2 200 μmol m−2 s−1 PPFD. TL and E were highly correlated. The optimum TL for maximum P
N was 26.0 °C after which P
N declined significantly. E had a positive correlation with P
N. 相似文献