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1.
Panomycocin, a novel exo-beta 1,3 glucanase, was tested as an antifungal agent against green and blue mold diseases, the most
important causes of post harvest decay in citrus fruits. All tested isolates of Penicillium digitatum and Penicillium italicum were susceptible to panomycocin in vitro. Effective panomycocin concentrations for 50% growth inhibition (MIC-2) for P. digitatum and P. italicum were 2 and 1 μg ml−1, respectively. Complete (MIC-0) growth inhibition of all isolates observed at a panomycocin concentration of 16 μg ml−1. Treatment of spores with panomycocin at values lower than the MIC-0 led to slower germ tube elongation and mycelium growth.
In tests on fruit, panomycocin at concentrations equal to in vitro MIC-0 value protected lemon fruit from decay. 相似文献
2.
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
3.
Park YJ Lee JY Yeom HR Kim KH Lee SC Shim IK Chung CP Lee SJ 《Biotechnology letters》2005,27(22):1761-1766
Injectable polysaccharide microcapsules holding minocycline were fabricated from alginate and chitosan for the treatment of
periodontitis. The microcapsules were examined for the release and degradation of minocycline, as well as antimicrobial activity.
The microcapsules were biodegradable and released minocycline between 10 and 1000 μg ml−1, which was higher than the usual therapeutic concentration (1–5 μg ml−1), for up to 7 days. These microcapsules showed a statistically significant suppression of pathogenic bacteria, such as Prevotella intermedia causing periodontitis. The microcapsules are thus potentially useful for drug delivery for the treatment of periodontitis. 相似文献
4.
In this study, the effects of inositol addition on expression of the MAL gene encoding maltase and phosphatidylinositol (PI) biosynthesis in Schizosaccharomyces pombe (a naturally inositol-requiring strain) were examined. We found that specific maltase activity was at its maximum when the concentration of added inositol reached 6 μg ml−1 in a synthetic medium containing 2.0% (w/v) glucose. When the concentration of added inositol was 1 μg ml−1 in the medium, repression of MAL gene expression occurred at glucose concentration higher than 0.2% (w/v). However, when S. pombe was cultured in the synthetic medium containing 6 μg ml−1, repression of maltase gene expression occurred only at initial glucose concentration above 1.0% (w/v). More mRNA encoding maltase was detected in the cells grown in the medium with 6 μg ml−1 inositol than in those grown in the same medium with 1 μg ml−1 inositol. These results demonstrate that higher inositol concentrations in the synthetic medium could derepress MAL gene expression in S. pombe. PI content of the yeast cells grown in the synthetic medium with 6 μg ml−1 of inositol was higher than that of the yeast cells grown in the same medium with 1 μg ml−1 of inositol. This means that PI may be involved in the derepression of MAL gene expression in S. pombe. 相似文献
5.
In this study, using a bioassay-guided isolation and purification procedure, we obtained 3-chloro-2,5-dihydroxybenzyl alcohol
from a marine-derived Ampelomyces species that effectively inhibited larval settlement of the tubeworm Hydroides elegans and of cyprids of the barnacle Balanus amphitrite. The inhibitive effect on larval settlement was nontoxic and the EC50 of 3-chloro-2,5-dihydroxybenzyl alcohol ranged from 3.19 μg ml−1 to 3.81 μg ml−1 while the LC50 was 266.68 μg ml−1 for B. amphitrite cyprids; EC50 ranged from 0.67 μg ml−1 to 0.78 μg ml−1, and LC50 was 2.64 μg ml−1 for competent larvae of H. elegans, indicating that inhibitive effect of this compound was nontoxic. At a concentration of 50 μg per disc, this compound showed
strong inhibitive effects on the growth of 13 out of 15 marine bacterial species tested in disc diffusion bioassay. Overall,
the high inhibitory activities against bacteria and larval settlement as well as the non- or low-toxic nature of this compound
to the barnacle and polychaete larvae suggest this compound could be a potent antifoulant and/or antibiotic. 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.
Arthrospira
platensis SAG 21.99 and the isolated bacteria (Halomonas spp., Staphylococcus sp., etc.) from the culture of A. platensis SAG 21.99 were treated with five antibiotics to determine the minimal lethal concentrations. The combination of a washing
step and a consecutive treatment with antibiotics, imipenem (100 μg ml−1), neomycin (100 μg ml−1) and cycloheximide (20 μg ml−1), treatment step was highly effective in eliminating bacteria. An axenic culture of A. platensis SAG 21.99 could be induced within 3 days using this method. This technique is a simple and rapid method for obtaining axenic
cultures of filamentous cyanobacteria. 相似文献
8.
Wiyakrutta Suthep Sriubolmas Nongluksna Panphut Wattana Thongon Nuntawan Danwisetkanjana Kannawat Ruangrungsi Nijsiri Meevootisom Vithaya 《World journal of microbiology & biotechnology》2004,20(3):265-272
A total of 81 Thai medicinal plant species collected from forests in four geographical regions of Thailand were examined for
the presence of endophytic fungi with biological activity. Of 582 pure isolates obtained, 360 morphologically distinct fungi
were selected for cultivation on malt Czapek broth and yeast extract sucrose broth, from which extracts were tested for biological
activity. Extracts of 92 isolates could inhibit Mycobacterium tuberculosis (MIC 0.0625–200 μg ml−1) when tested by the microplate Alamar blue assay, while extracts of six inhibited Plasmodium falciparum (IC50 of 1.2–9.1 μg ml−1) as determined by the [3H]hypoxanthine incorporation method. Strong anti-viral activity against Herpes simplex virus type 1 was observed in 40 isolates
(IC50 of 0.28–50 μg ml−1). The sulphorhodamine B assay for activity against cancer cell lines revealed that 60 were active against human oral epidermoid
carcinoma cells (EC50 0.42–20 μg ml−1) and 48 against breast cancer cells (EC50 0.18–20 μg ml−1). Bioactivity profile was affected by the type of culture medium. Given the high incidence of bioactive extracts and the
fact that most of the isolated fungi could not be identified due to lack of spore formation, the results suggested that Thai
medicinal plants can provide a wide variety of endophytes that might be a potential source of novel bioactive compounds.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
9.
Mustafa Çelik Fatma Ünal Deniz Yüzbaşıoğlu Serkan Yılmaz Hüseyin Aksoy Şengül Karaman 《Cytotechnology》2006,51(2):99-104
In this investigation, clastogenic effects of Thymus kotschyanus var. glabrescens Boiss. extract (TE) and anticlastogenic effects of this extract against Mitomycin C (MMC) induced chromosome damage have been evaluated in human peripheral blood lymphocytes in vitro. Two series of experiments were conducted. In the first, only 10−5, 10−4, 10−3 and 10−2 μl ml−1 concentrations of TE were used for 48 h to detect potential clastogenicity. In the second, MMC (0.38 μg ml−1) plus 10−5, 10−4, 10−3 and 10−2 μl ml−1 concentrations of TE were used for 48 h to determine anticlastogenic effects. TE did not increase sister chromatid exchanges (SCEs) (except 10−2 μl ml concentration) and chromosome aberrations (CAs) significantly compared with negative and solvent controls. However, it decreased the frequency of MMC induced chromosome aberrations. Decreasing was significant at 10−4, 10−3 and 10−2 μl ml−1 concentrations. On the other hand, TE significantly increased MMC-induced SCEs for all treatment groups compared with positive control. 相似文献
10.
Boiero L Perrig D Masciarelli O Penna C Cassán F Luna V 《Applied microbiology and biotechnology》2007,74(4):874-880
The aim of this work was to evaluate phytohormone biosynthesis, siderophores production, and phosphate solubilization in three
strains (E109, USDA110, and SEMIA5080) of Bradyrhizobium japonicum, most commonly used for inoculation of soybean and nonlegumes in USA, Canada, and South America. Siderophore production and
phosphate solubilization were evaluated in selective culture conditions, which had negative results. Indole-3-acetic acid
(IAA), gibberellic acid (GA3), and abscisic acid (ABA) production were analyzed by gas chromatography–mass spectrometry (GC-MS). Ethylene and zeatin biosynthesis
were determined by GS–flame ionization detection and high-performance liquid chromatography (HPLC-UV), respectively. IAA,
zeatin, and GA3 were found in all three strains; however, their levels were significantly higher (p < 0.01) in SEMIA5080 (3.8 μg ml−1), USDA110 (2.5 μg ml−1), and E109 (0.87 μg ml−1), respectively. ABA biosynthesis was detected only in USDA110 (0.019 μg ml−1). Ethylene was found in all three strains, with highest production rate (18.1 ng ml−1 h−1) in E109 cultured in yeast extract mannitol medium plus l-methionine. This is the first report of IAA, GA3, zeatin, ethylene, and ABA production by B. japonicum in pure cultures, using quantitative physicochemical methodology. The three strains have differential capability to produce
the five major phytohormones and this fact may have an important technological implication for inoculant formulation. 相似文献
11.
Ajit Kumar Shasany Suman P. S. Khanujia Sunita Dhawan Usha Yadav Srikant Sharma Sushil Kumar 《Journal of biosciences》1998,23(5):641-646
Media and incubation conditions have been defined for highly efficient regeneration of shoots from internode explants of slow
and fast growing cultivars ofMentha arvensis. Internodal segments excised from thein vitro raised shoots were inoculated on the MS medium supplemented with combinations of 5 concentrations of l-napthalene acetic
acid (NAA) and 3 concentrations of 6-benzyl amino purine (BAP). The media containing 2 μg ml−1 NAA, 10 Μg ml−1 BAP and 1 μg ml−1 NAA, 5 μg ml−1 BAP proved best for shoot regeneration and growth responses on cv Himalaya and cv Kalka explants, respectively. In 12 weeks
time, on average one explant of cv Himalaya produced about 200 shoots and that of cv Kalka produced about 180 shoots. The
Himalaya explants required higher concentrations of NAA and BAP for high efficiency proliferation as compared to the Kalka
explants. The experiments demonstrated that internodal tissue inMentha arvensis can be induced to obtain direct shoot regenerants with high efficiency. The analysis of the RAPD profiles of 100 regenerated
plantlets each of cv Himalaya and Kalka showed more than 99.9% homogeneity in bands with respect to the parents. 相似文献
12.
Biological control and induced resistance are two of the promising approaches to the control of postharvest diseases. This
study was conducted to evaluate the efficacy of salicylic acid (SA) alone or in combination with an antagonistic yeast, Cryptococcus laurentii, in controlling the blue mold disease caused by Penicillium expansum on apple fruit wounds. SA alone significantly inhibited the spore germination of P. expansum in vitro when its concentration was increased to 1000 μg ml−1, but it was not effective in controlling the disease in vivo. Simultaneous application of SA and C. laurentii to the wounds on the apple fruit surface showed that SA could improve the efficacy of C. laurentii against P. expansum in a concentration-dependent manner, being most effective at 10 μg ml−1 but less effective at a higher or lower concentrations. Besides reducing the blue mold incidence in the local wound sites,
the combination of C. laurentii with SA at 10 μg ml−1 also had a synergistic effect on the induction of fruit resistance to the disease, which might be associated with a rapid
increase in peroxidase, phenylalanineamonialyase and lipoxygenase activities. In addition, SA at 100 μg ml−1 or above showed an adverse effect on the growth of C. laurentii in vitro and in vivo, whereas it had no effect when its concentration was decreased to 10 μg ml−1 or lower. This suggested that SA could enhance the biological activity of C. laurentii in apple fruit by inducing resistance to pathogens based on the antagonistic activity of C. laurentii. 相似文献
13.
The plant growth–promoting potentials, production of siderophore and solubilization of insoluble phosphorus (P) and zinc and
lead by the chromium (vi) -reducing Bacillus species, PSB 1, PSB 7, and PSB 10, was assessed both in the presence and absence of chromium under in vitro conditions. The Bacillus strains tolerated chromium up to the concentration of 500 (PSB1), 400 (PSB7), and 550 μg ml−1 (PSB10), respectively, on nutrient agar plates. Bacillus sp. PSB 10 reduced Cr (vi) by 87% at pH 7, which was followed by Bacillus sp. PSB 1 (83%) and PSB 7 (74%) in nutrient broth after 120 h of incubation. A concentration of 50 μg ml−1 of Cr (vi) was completely reduced by Bacillus sp. PSB 1 and PSB 10 (after 100 h) and PSB 7 (after 120 h). The Bacillus strains PSB 1, PSB 7, and PSB 10 produced 19.3, 17.7, and 17.4 μg ml−1 of indole acetic acid, respectively, in luria bertani broth at 100 μg ml−1 of tryptophan, which consistently decreased with an increase in chromium concentration. The Bacillus strains were positive for siderophore, HCN, and ammonia both in the absence and presence of chromium. The Bacillus strains solubilized 375 (PSB 1), 340 (PSB 7), and 379 (PSB 10) μg ml−1 P, respectively, in Pikovskaya broth devoid of chromium. In contrast, chromium at 150 μg ml−1 reduced the amount of P solubilized by 17 (PSB 1), 15 (PSB 7), and 9% (PSB 10) compared to control. The tested bacterial
strains solubilized a considerable amount of zinc and lead in nutrient broth both in the absence and presence of chromium.
Generally, the chromium reduction and the plant growth–promoting potentials of chromium-reducing Bacillus were strongly correlated at the tested concentration of chromium. The present observations demonstrated that the chromium-reducing,
metal-solubilizing, and plant growth–promoting potentials of the Bacillus strains PSB1, PSB 7, and PSB10 were not adversely affected by the chromium application and, hence, may be applied for raising
the productivity of crops under metal-contaminated soils. 相似文献
14.
Artemisinin production by hairy roots of Artemisia annua L. was increased 6-fold to 1.8 μg mg−1 dry wt over 6 days by adding 150 mg chitosan l−1. The increase was dose-dependent. Similar treatment of hairy roots with methyl jasmonate (0.2 mM) or yeast extract (2 mg ml−1) increased artemisinin production to 1.5 and 0.9 μg mg−1 dry wt, respectively. 相似文献
15.
Candida cylindracea NRRL Y-17506 was grown to produce extracellular lipase from oleic acid as a carbon source. Through flask cultures, it was found that the optimum initial oleic acid concentration for cell growth was 20 g l−1. However, high initial concentrations of oleic acid up to 50 g l−1 were not inhibitory. The highest extracellular lipase activity obtained in flask culture was 3.0 U ml−1 after 48 h with 5 g l−1 of initial oleic acid concentration. Fed-batch cultures (intermittent and stepwise feeding) were carried out to improve cell concentration and lipase activity. For the intermittent feeding fed-batch culture, the final cell concentration was 52 g l−1 and the extracellular lipase activity was 6.3 U ml−1 at 138.5 h. Stepwise feeding fed-batch cultures were carried out to simulate an exponential feeding and to investigate the effects of specific growth rate (0.02, 0.04 and 0.08 h−1) on cell growth and lipase production. The highest final cell concentration obtained was 90 g l−1 when the set point of specific growth rate (μset) was 0.02 h−1. High specific growth rate (0.04 and 0.08 h−1) decreased extracellular lipase production in the later part of fed-batch cultures due to build-up of the oleic acid oversupplied. The highest extracellular lipase activity was 23.7 U ml−1 when μset was 0.02 h−1, while the highest lipase productivity was 0.31 U ml−1 h−1 at μset of 0.08 h−1. 相似文献
16.
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
17.
Isolation and characterization of dihydromonacolin-MV from <Emphasis Type="Italic">Monascus purpureus</Emphasis> for antioxidant properties 总被引:4,自引:0,他引:4
Dhale MA Divakar S Kumar SU Vijayalakshmi G 《Applied microbiology and biotechnology》2007,73(5):1197-1202
The methanolic extract of Monascus purpureus cultivated by solid-state fermentation on rice showed strong 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity
and better yield as compared to other polarity based extracted fractions. It was selected for further purification of the
antioxidant. The activity-guided repeated fractionation of methanolic extract on a silica gel column chromatography yielded
a compound that exhibited strong antioxidant activity. Based on the spectroscopic analysis by UV, IR, 1H NMR, 13C NMR, 2D-HSQCT NMR, and MS, the antioxidant isolated was elucidated as a derivative of dihydromonacolin-K, where the ester
group is 2-methyl propionate, designated as dihydromonacolin-MV. The DPPH radical was significantly scavenged by the dihydromonacolin-MV
(IC50 20±1 μg ml−1). The dihydromonacolin-MV showed strong inhibition of lipid peroxidation in a liposome model with an IC50 value of 5.71±0.38 μg ml−1 and superoxide radical scavenging activity with an IC50 value of 163.97±2.68 μg ml−1. 相似文献
18.
A Bacillus sp. RE was resistant to chromium and reduced Cr(VI) without accumulating chromium inside the cell. When Cr(VI) was 10 and
40 μg ml−1, >95% of the total Cr(VI) was reduced in 24 and 72 h of growth, respectively, whereas at 80 μg Cr(VI) ml−1 only 50% of Cr(VI) was reduced. However growth was not affected; the cell mass was 0.7–0.8 mg ml−1 in all cases. The cell-free extract showed Cr(VI) reducing enzyme activity which was enhanced (>5 fold) by NADH and NADPH.
Like whole cells the enzyme also reduced Cr(VI) with decreasing efficiency on increasing Cr(VI) concentration. The enzyme
activity was optimal at pH 6.0 and 30 °C. The enzyme was stable up to 30 °C and from pH 5.5 to 8, but from pH 4 to 5 the enzyme
was severely destabilized. Its Km and Vmax were 14 μm and 3.8 nmol min−1 mg−1 respectively. The enzyme activity was enhanced by Cu2+ and Ni2+ and inhibited by Hg2+.
Received 21 September 2005; Revisions requested 5 October 2005; Revisions received 16 November 2005; Accepted 16 November
2005 相似文献
19.
We evaluated the combined effects of algal (Chlorella vulgaris) food levels (low, 0.5 × 106 (or 2.9 μg C ml−1); and high, 1 × 106 cells ml−1 (or 5.8 μg C ml−1)) and zinc concentrations (0, 0.125, and 0.250 mg l−1 of ZnCl2) on the competition between two common planktonic rotifers Anuraeopsis fissa and Brachionus rubens using their population growth. Median lethal concentration data (LC50) (mean ± 95% confidence intervals) showed that B. rubens was more resistant to zinc (0.554 ± 0.08 mg l−1) than A. fissa (0.315 ± 0.07 mg l−1). A. fissa when grown alone or with Zn was always numerically more abundant than B. rubens. When grown in the absence of zinc, under low- and high-food levels, the peak abundances of A. fissa varied from 251 ± 24 to 661 ± 77 ind. ml−1, respectively, and the corresponding maxima for B. rubens were 52 ± 3 and 102 ± 18 ind. ml−1. At a given food level, competition for food reduced the peak abundances of both rotifers considerably. Increase in Zn concentration
also lowered the rotifer abundances. The impact of zinc on competition between the two-rotifer species was evident at low-food
level, mainly for A. fissa. At zinc concentrations of 0 and 0.125 mg l−1, the populations of both rotifers continued to grow for about 10 days, but thereafter B. rubens began to decline. Role of zinc on the competitive outcome of the two species is discussed in relation to the changing algal
densities in natural water bodies. 相似文献
20.
Anju Arora Sudhir Saxena Dinesh Kumar Sharma 《World journal of microbiology & biotechnology》2006,22(2):97-100
Azolla, an aquatic fern is ideal candidate for exploitation in constructed wetlands for treating metal-contaminated wastewaters. This study demonstrates the potential of Azolla spp. namely A. microphylla, A. pinnata and A.␣filiculoides to tolerate Cr ions in the growth environment and bioconcentrate them. These species could grow in presence of up to 10 μg ml−1 Cr and showed biomass production 30–70% as compared to controls. Nitrogenase activity was not affected at 1–5 μg ml−1 but at higher concentrations it diminished. There was no growth at higher concentrations of chromium. However, the necrosed biomass harvested from treatments containing higher concentrations of chromium, accumulated Cr to the levels 5000–15,000 μg g−1. At increased levels of Cr, the metal was accumulated in higher amount in dry biomass. Bioconcentration Factor (BCF) ranged between 243 and 4617 for the three species. A. microphylla showed highest bioconcentration potential. Thus, these Azolla spp. can be exploited for treatment of tannery and other Cr contaminated wastewaters. 相似文献