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1.
Ansari MA Khan HM Khan AA Sultan A Azam A 《Applied microbiology and biotechnology》2012,94(2):467-477
The reemergence of infectious diseases and the continuous development of multidrug resistance among a variety of disease-causing
bacteria in clinical setting pose a serious threat to public health worldwide. Extended-spectrum β-lactamases (ESBLs) that
mediate resistance to third-generation cephalosporin are now observed all over the world in all species of Enterobacteriaceae,
especially Escherichia coli and Klebsiella pneumoniae. In this work, ZnO nanoparticles (NPs) were synthesized by the sol–gel method and characterized by powder X-ray diffraction,
scanning electron microscopy (SEM) and atomic force microscopy (AFM). The image of synthesized ZnO NPs appeared spherical
in SEM with a diameter of ≈19 nm and as hexagonal crystal in AFM. Clinical isolates were assessed for ESBL production and
shown to be sensitive to ZnO NPs by different methods such as minimal inhibitory concentration (MIC) and minimal bactericidal
concentration, time-dependent growth inhibition assay, well diffusion agar methods and estimation of colony forming units
(CFU) of bacteria. The lowest MIC value for E. coli and K. pneumoniae was found to be 500 μg/ml. The results showed that ZnO NPs at 1,000 μg/ml completely inhibit the bacterial growth. The antibacterial
effect of ZnO nanoparticles was gradual, but time- and concentration-dependent. The maximum inhibition zone at100 μg/ml for
E. coli and K. pneumoniae was 22 and 20 mm, respectively. With the increasing ZnO NP loading, there is significant reduction in the numbers of CFU.
At the concentration of 1,000 μg/ml, the decline in per cent survival of E. coli and K. pneumoniae was found to be 99.3% and 98.6%, respectively. 相似文献
2.
Ilkay Orhan Berrin Özçelik Sinem Aslan Murat Kartal Taner Karaoglu Bilge Şener Salih Terzioglu M. Iqbal Choudhary 《Phytochemistry Reviews》2007,6(1):189-196
Purpose of the present study was to evaluate antioxidant, antibacterial, antifungal, and antiviral activities of the petroleum
ether, chloroform, ethyl acetate and methanol extracts as well as the alkaloid fraction of Lycopodium clavatum L. (LC) from Lycopodiaceae growing in Turkey. Antioxidant activity of the LC extracts was evaluated by 1,1-diphenyl-2-picrylhydrazyl
(DPPH) radical-scavenging method at 0.2 mg/ml using microplate-reader assay. Antiviral assessment of LC extracts was evaluated
towards the DNA virus Herpes simplex (HSV) and the RNA virus Parainfluenza (PI-3) using Madin-Darby Bovine Kidney (MDBK) and Vero cell lines. Antibacterial and antifungal activities of the extracts
were tested against standard and isolated strains of the following bacteria; Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis, Acinobacter baumannii, Klebsiella pneumoniae, Staphylococcus aureus, Bacillus subtilis as well as the fungi; Candida albicans and C. parapsilosis. All of the extracts possessed noteworthy activity against ATCC strain of S. aureus (4 μg/ml), while the LC extracts showed reasonable antifungal effect. On the other hand, we found that only the chloroform
extract was active against HSV (16–8 μg/ml), while petroleum ether and alkaloid extracts inhibited potently PI-3 (16–4 μg/ml
and 32–4 μg/ml, respectively). However, all of the extracts had insignificant antiradical effect on DPPH. In addition, we
also analyzed the content of the alkaloid fraction of the plant by capillary gas chromatography-mass spectrometry (GC-MS)
and identified lycopodine as the major alkaloid. 相似文献
3.
A bacterium identified as Pseudomonas fluorescence was isolated from Taxus baccata rhizosphere. Ethyl acetate extract from its culture filtrate yielded an active antimicrobial compound that was purified by
TLC. The active metabolites were resolved by column chromatography on silica gel (60–120 mesh). The compound was further characterized
on the basis of spectral data (UV, IR and 1HNMR), which indicated the presence of an aromatic ring and phenolic functionality. The compound showed significant antimicrobial
activity against two-gram positive bacteria (B. subtilis and S. aureus), four-gram negative bacteria (E. coli, K. pneumoniae, S. flexneri and P. aeruginosa), and one pathogenic fungus (Candida albicans). The minimum inhibitory concentration (MIC) of the compound ranged between 75μg to 250 μg/ml. 相似文献
4.
The food pathogen Bacillus cereus is likely to encounter acidic environments (i) in food when organic acids are added for preservation purposes, and (ii) during the stomachal transit of aliments. In order to characterise the acid stress response of B. cereus ATCC14579, cells were grown in chemostat at different pH values (pHo from 9.0 to 5.5) and different growth rates (μ from 0.1 to 0.8 h−1), and were submitted to acid shock at pH 4.0. Cells grown at low pHo were adapted to acid media and induced a significant acid tolerance response (ATR). The ATR induced was modulated by both pHo and μ, and the μ effect was more marked at pHo 5.5. Intracellular pH (pHi) was affected by both pHo and μ. At a pHo above 6, the pHi decreased with the decrease of pHo and the increase of μ. At pHo 5.5, pHi was higher compared to pHo 6.0, suggesting that mechanisms of pHi homeostasis were induced. The acid survival of B. cereus required protein neo-synthesis and the capacity of cells to maintain their pHi and ΔpH (pHi - pHo). Haemolysin BL and non-haemolytic enterotoxin production were both influenced by pHo and μ. 相似文献
5.
Forty-six Rhizobium isolates from legume root and stem nodules were examined for their phosphate-solubilizing ability on Pikovskaya’s agar medium.
Rhizobium isolates from root nodules of Cassia absus, Vigna trilobata and three strains from Sesbania sesban showed zone of tricalcium phosphate (TCP) solubilization. The isolate from C. absus showed maximum solubilization (620 μg/ml) after 12 d of incubation, while the Rhizobium sp. strain 26 (from S. sesban) showed the least amount (150 μg/ml) of phosphate solubilization. Among the carbon sources tested for their ability to solubilize
TCP, maximum solubilization (620 μg/ml) was observed in glucose by Rhizobium isolate from C. absus. Phosphate solubilization increased with increase in glucose concentration steeply up to 2% and slowly
above this concentration in four isolates. Among the nitrogen sources tested, maximum solubilization (620 μg/ml) was observed
in ammonium sulphate by Rhizobium isolate from C. absus. 相似文献
6.
Manmeet Sakshi Bedi Vivek Verma Sanjay Chhibber 《World journal of microbiology & biotechnology》2009,25(7):1145-1151
Despite the efficacy of antibiotics as well as bacteriophages in treatment of bacterial infections, their role in treatment
of biofilm associated infections is still under consideration especially in case of older biofilms. Here, efficacy of bacteriophage
alone or in combination with amoxicillin, for eradication of biofilm of Klebsiella pneumoniae B5055 has been assessed. Planktonic cells as well as biofilm of K. pneumoniae B5055 grown in 96-well microtiter plates were exposed to bacteriophage and amoxicillin at various Multiplicity of Infections
(MoIs) as well as at three different antibiotic concentrations (512, 256 and 128 μg/ml), respectively. After exposure to 256 μg/ml
(MIC) of amoxicillin, bacterial load of planktonic culture as well as 1-day-old biofilm was reduced by a log factor of 4.1 ± 0.31
(P = 0.008) and 1.24 ± 0.27 (P < 0.05), respectively but reduction in the bacterial load of mature biofilm (8-day-old) was insignificant (P = 0.23). When 8-day-old biofilm was exposed to higher antibiotic concentration (512 μg/ml) or phage alone (MoI = 0.01) a
log reduction of 2.97 ± 0.11 (P = 0.182) and 3.51 ± 0.19 (P = 0.073), respectively was observed. While on exposing to a combination of both the amoxicillin and phage, a significant
reduction (P < 0.01) in bacterial load of the biofilm was seen. Hence, when antibiotic was used in combination with specific bacteriophage
a greater destruction of the biofilm structure suggested that the phages could be used successfully along with antibiotic
therapy. An added advantage of the combination therapy would be its ability to check formation of resistant mutants that otherwise
develop easily upon using phage or antibiotic alone. 相似文献
7.
Morphometry and growth of three <Emphasis Type="Italic">Synechococcus</Emphasis>-like picoplanktic cyanobacteria at different culture conditions 总被引:1,自引:1,他引:0
Three phycocyanin-rich strains of Synechococcus-like picoplanktic cyanobacteria, isolated from the plankton of Czech oligotrophic to eutrophic freshwater reservoirs, were
investigated in crossed gradients of light and temperature and in combination with two different culture media (BG-11 and
WC). The strains exhibited similar growth and reproduction patterns and displayed overlapping ranges of cell size (1.5 × 0.8
μm) under standardized laboratory conditions (18 μmol m−2 s−1; 20°C). However, strains behavior differed in the crossed gradients. All strains preferred BG-11 medium, where also remarkable
size changes could be observed. Length, width, cell abundance and growth rate of two strains were positively correlated with
temperature and nutrients, whereas the impact of light intensity was insignificant. Maximum cell elongation (involution cells
up to 19 μm) occurred in two strains only in BG-11 medium at highest temperature (28°C) and highest irradiance (53 μmol m−2 s−1). Cell dimensions in WC medium were constant under most conditions given. The third strain was influenced by all three factors,
from which light and nutrients played pivotal role. The length of the lag-phase for all strains appeared to be temperature
dependent (negative correlation). Despite the fact that the cell volume in all strains increased more than five times under
the lowest light and low temperature (6 μmol m−2 s−1, <15°C) in both media, the length/width ratio remained unchanged. The strains differed in the degree of cell enlargement
and cell division symmetry as well as in optimum temperature and light dependence. Based on this experimental work two strains
could be identified as Synechococcus sp. and one as Cyanobium sp., which can be used as a support for the following genetical analyses. 相似文献
8.
Guo-Qiu Wu Jia-Xuan Ding Lin-Xian Li Hai-liang Wang Rui Zhao Zi-Long Shen 《Current microbiology》2009,59(2):147-153
The treatment of infections caused by bacteria resistant to the vast majority of antibiotics is a challenge worldwide. To
evaluate the effect of S-thanatin (an analog of thanatin, a cationic antimicrobial peptide isolated from the hemipteran insect
Podisus maculiventris) against microbial resistant to antibiotics, we studied its bactericidal kinetics, synergistic effect, resistance, and activity
on clinical isolates of Klebsiella pneumoniae resistant to conventional antibiotics with different structures. The bactericidal rate of S-thanatin was more than 99% against
K. pneumoniae ATCC 700603 when bacterial cultures were monitored for 60 min. The peptide was synergistic with β-lactam cefepime in most
of the clinical MDR isolates tested (7/8). An average value of FIC was 0.3708. No synergy was found between the peptide and
amoxicillin, gentamycin, tetracycline, or ciprofloxacin in all bacteria tested. A total of 48 isolates of K. pneumoniae with different resistance spectrum tested was susceptible to S-thanatin. The MICs were 6.25–25 μg/ml. No significant difference
in the MICs of S-thanatin between the sensitive isolates and the resistant isolates to single antibiotic was observed (P > 0.05). The resistance of K. pneumoniae ATCC 700603 to S-thanatin was slightly higher, when cultured at sub-inhibitory concentration for 5 days. S-thanatin may be
an attractive candidate for developing into an antimicrobial agent. 相似文献
9.
Min Zhang Xiaomin Hang Xiaobing Fan Daotang Li Hong Yang 《World journal of microbiology & biotechnology》2008,24(1):7-14
Fourteen Lactobacillus strains of six species were investigated with their characteristics of bile salt tolerance, deconjugation of sodium taurocholate
and cholesterol removal in the spent broth. Meanwhile, a co-precipitation curve of cholesterol with cholic acid at concentrations
ranged 0.0–6.0 μM/ml was involved in the evaluation of cholesterol removal. Results demonstrated that both co-precipitation
and assimilation effects contributed to cholesterol removal during the incubation of these Lactobacillus strains. It was also indicated that the supplementation of bile salts influenced the cholesterol removal, not only as an
essential factor related to co-precipitation but also a critical condition for cholesterol assimilation. Out of all strains
tested, four L. plantarum strains LS12, LS31, Lp501 and Lp529 exhibited a high ability of cholesterol assimilation (maximum 20.76 μg/ml), deconjugation
of sodium taurocholate (maximum 5.00 μM/ml) and bile tolerance. They could be further studied and used as potential probiotics
strains to reduce serum cholesterol in humans 相似文献
10.
Wen-Ru Li Xiao-Bao Xie Qing-Shan Shi Hai-Yan Zeng You-Sheng OU-Yang Yi-Ben Chen 《Applied microbiology and biotechnology》2010,85(4):1115-1122
The antibacterial activity and acting mechanism of silver nanoparticles (SNPs) on Escherichia coli ATCC 8739 were investigated in this study by analyzing the growth, permeability, and morphology of the bacterial cells following
treatment with SNPs. The experimental results indicated 10 μg/ml SNPs could completely inhibit the growth of 107 cfu/ml E. coli cells in liquid Mueller–Hinton medium. Meanwhile, SNPs resulted in the leakage of reducing sugars and proteins and induced
the respiratory chain dehydrogenases into inactive state, suggesting that SNPs were able to destroy the permeability of the
bacterial membranes. When the cells of E. coli were exposed to 50 μg/ml SNPs, many pits and gaps were observed in bacterial cells by transmission electron microscopy and
scanning electron microscopy, and the cell membrane was fragmentary, indicating the bacterial cells were damaged severely.
After being exposed to 10 μg/ml SNPs, the membrane vesicles were dissolved and dispersed, and their membrane components became
disorganized and scattered from their original ordered and close arrangement based on TEM observation. In conclusion, the
combined results suggested that SNPs may damage the structure of bacterial cell membrane and depress the activity of some
membranous enzymes, which cause E. coli bacteria to die eventually. 相似文献
11.
Aspergillus strains are being considered as potential hosts for recombinant heterologous protein production because of their excellent
extracellular enzyme production characteristics. However, Aspergillus proteases are problematic in that they modify and degrade the heterologous proteins in the extracellular medium. In previous
studies we observed that media adjustments and maintenance of a filamentous morphology greatly reduced protease activity and
that a low concentration of the aspartic protease inhibitor pepstatin inhibited the latter protease activity to the extent
of approximately 90%. In this paper we report that when the serine protease inhibitor chymostatin is used in combination with
pepstatin 99–100% of total protease activity in Aspergillus cultures is inhibited. In protease assays a concentration of 30 μM chymostatin combined with 0.075 μM pepstatin was required
for maximum inhibition. Inhibitor concentrations of chymostatin and pepstatin of 120 and 0.3 μM, respectively, when added
to Aspergillus cultures, has no significant effect on biomass production, glucose utilization or culture pH pattern. The potential of using
these protease inhibitors in cultures of recombinant Aspergillus strains producing heterologous proteins will now be investigated to determine if the previously observed recombinant protein
denaturing effects of Aspergillus proteases can be negated. 相似文献
12.
Although resistance of microorganisms to Hg(II) salts has been widely investigated and resistant strains have been reported
from many eubacterial genera, there are few reports of mercuric ion resistance in extremophilic microorganisms. Moderately
thermophilic mercury resistant bacteria were selected by growth at 62 °C on Luria agar containing HgCl2. Sequence analysis of 16S rRNA genes of two isolates showed the closest matches to be with Bacillus pallidus and Ureibacillus thermosphaericus. Minimum inhibitory concentration (MIC) values for HgCl2 were 80 μg/ml and 30 μg/ml for these isolates, respectively, compared to 10 μg/ml for B. pallidus H12 DSM3670, a mercury-sensitive control. The best-characterised mercury-resistant Bacillus strain, B. cereus RC607, had an MIC of 60 μg/ml. The new isolates had negligible mercuric reductase activity but removed Hg from the medium
by the formation of a black precipitate, identified as HgS by X-ray powder diffraction analysis. No volatile H2S was detected in the headspace of cultures in the absence or presence of Hg2+, and it is suggested that a new mechanism of Hg tolerance, based on the production of non-volatile thiol species, may have
potential for decontamination of solutions containing Hg2+ without production of toxic volatile H2S. 相似文献
13.
Damayanti De Ananda Mukhopadhyay Ranadhir Chakraborty 《World journal of microbiology & biotechnology》2008,24(11):2727-2729
Enterobacter sp. was isolated from the diseased and dead caterpillars of the tea leaf roller (Caloptilia theivora) from the Darjeeling foothill region. When the vegetative form of the bacterium was applied via food, mortality of C. theivora showed an LC50 value at 363.1 μg/ml (bacterial wt./vol. of water) with fiducial limits 363.25 and 362.94 μg/ml respectively. The LT50 values for C. theivora were 6 days for 100 μg/ml, 5.96 days for 300 μg/ml, 5.81 days for 500 μg/ml, 4.96 days for 750 μg/ml and 4.61 days for 1,000 μg/ml
concentrations. The finding would enable one to contemplate development of a microbial pesticide using this novel Enterobacter sp. DD01 for control of the leaf rolling pest. 相似文献
14.
Ruixiang Zhao Junliang Sun Peter Torley Dahong Wang Shengyang Niu 《World journal of microbiology & biotechnology》2008,24(8):1349-1354
Lactobacillus acidophilus, as a probiotic, is widely used in many functional food products. Microencapsulation not only increases the survival rate
of L. acidophilus during storage and extends the shelf-life of its products, but also optimal size microcapsule makes L. acidophilus have an excellent dispersability in final products. In this paper, L. acidophilus was microencapsulated using spray drying (inlet air temperature of 170°C; outlet air temperature of 85–90°C). The wall materials
used in this study were β-cyclodextrin and acacia gum in the proportion of 9:1 (w/w), and microcapsules were prepared at four
levels of wall materials (15, 20, 25 and 30% [w/v]) with a core material concentration of 6% (v/v). The microcapsule diameters
were measured by Malvern’s Mastersizer-2000 particle size analyzer. The results showed that the particle diameters of microcapsule
were mostly within 6.607 μm and 60.256 μm and varied with 2.884–120.226 μm (the standard smaller microcapsule designated as
<350 μm). Through comparison of microcapsule size and uniformity with different concentration of wall materials, we concluded
that the optimal concentration of wall material was 20% (w/v), which gave microcapsule with a relatively uniform size (averaging
22.153 μm), and the number of surviving encapsulated L. acidophilus was 1.50 × 109 c.f.u./ml. After 8 weeks storage at 4°C, the live bacterial number was above 107 c.f.u./ml, compared with unencapsulated L. acidophilus, 104–105 c.f.u./ml. Through the observation of scanning electron microscopy, we found that the shapes of microcapsule were round and
oval, and L. acidophilus cells located in the centre of microcapsule. 相似文献
15.
Luiz Fernando W. Roesch Patricia Dörr de Quadros Flávio A. O. Camargo Eric W. Triplett 《World journal of microbiology & biotechnology》2007,23(10):1377-1383
Isolation of microorganisms, screening for desirable characters and selection of efficient strains are important steps to
optimize high crop yields and improve the sustainability of the ecosystem. The objective of this study was isolate and identify
Azopirillum spp. with enhanced potential to promote plant growth among the natural bacterial population associated with rhizosphere soil,
roots and stem of maize collected from five maize-growing regions within the southern state of Rio Grande do Sul in Brazil.
Diazotrophic microorganisms were isolated using semi-solid N-free and solid selective media NFb. In order to select the most
efficient isolates as candidates for plant growth promotion, the purified bacterial strains were studied for cell morphology,
and Gram staining, streptomycin resistance, as well as screened for their potential for nitrogen fixation and auxin production
under sterile conditions. Among 224 isolates obtained 121 were able to fix nitrogen and produce auxin. The 30 most promising
isolates produced indole-3-acetic acid (IAA) ranging in concentration from 3.51 μg to 246.69 μg IAA mg−1. Nitrogen fixation ranged from 15.43 μg to 95.21 μg of N mg protein−1 day−1 From the 30 most productive isolates, chromosomal DNA was extracted and a portion of the nifH gene was amplified and sequenced. Twenty-nine isolates were found to be similar to the Azospirillum genus and one isolate was found to be similar to Herbaspirillum seropedicae. These bacterial isolates revealed potential to increase crop productivity, however field crop experiments in Rio Grande
do Sul climatic conditions should be done in order to formulate recommendations for their use as inoculants. 相似文献
16.
Guang-fei Liu Ji-ti Zhou Yuan-yuan Qu Xin Ma 《World journal of microbiology & biotechnology》2007,23(7):931-937
Sulfonated azo dyes were decolorized by two wild type photosynthetic bacterial (PSB) strains (Rhodobacter sphaeroides AS1.1737 and Rhodopseudomonas palustris AS1.2352) and a recombinant strain (Escherichia coli YB). The effects of environmental factors (dissolved oxygen, pH and temperature) on decolorization were investigated. All
the strains could decolorize azo dye up to 900 mg l−1, and the correlations between the specific decolorization rate and dye concentration could be described by Michaelis–Menten
kinetics. Repeated batch operations were performed to study the persistence and stability of bacterial decolorization. Mixed
azo dyes were also decolorized by the two PSB strains. Azoreductase was overexpressed in E. coli YB; however, the two PSB strains were better decolorizers for sulfonated azo dyes. 相似文献
17.
Antibacterial activity of ZnO nanoparticles prepared via non-hydrolytic solution route 总被引:1,自引:0,他引:1
Rizwan Wahab Amrita Mishra Soon-Il Yun Young-Soon Kim Hyung-Shik Shin 《Applied microbiology and biotechnology》2010,87(5):1917-1925
The antibacterial activity of ZnO nanoparticles has been investigated and presented in this paper. Nanoparticles were prepared
via non-hydrolytic solution process using zinc acetate di-hydrate (Zn(CH3COO)2·2H2O) and aniline (C6H5NH2) in 6 h refluxing at ∼65 °C. In the presence of four pathogens such as Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, and Klebsiella pneumoniae, the antibacterial study of zinc oxide nanoparticles were observed. The antibacterial activity of ZnO nanoparticles (ZnO-NPs) were studied by spectroscopic method taking different concentrations
(5–45 μg/ml) of ZnO-NPs. Our investigation reveals that the lowest concentration of ZnO-NPs solution inhibiting the growth
of microbial strain is found to be 5 μg/ml for K. pneumoniae, whereas for E. coli, S. aureus, and S. typhimurium, it was calculated to be 15 μg/ml. The diameter of each ZnO-NPs lies between “20 and 30 nm” as observed from FESEM and transmission
electron microscopy images. The composition of synthesized material was analyzed by the Fourier transform infrared spectroscopy,
and it shows the band of ZnO at 441 cm−1. Additionally, on the basis of morphological and chemical observations, the chemical reaction mechanism of ZnO-NPs was also
proposed. 相似文献
18.
Bischoff KM Skinner-Nemec KA Leathers TD 《Journal of industrial microbiology & biotechnology》2007,34(11):739-744
Bacterial contamination of commercial fermentation cultures is a common and costly problem to the fuel ethanol industry. Antimicrobials
such as virginiamycin (VIR) and penicillin (PEN) are frequently used to control contamination but there are little data available
on the susceptibility of bacterial contaminants to these agents. A survey of bacterial contaminants from a wet-mill ethanol
plant with no history of using antibiotics and a dry-grind facility that periodically doses with VIR found that the majority
of contaminants were species of Lactobacillus. Thirty-seven isolates of Lactobacillus species from the wet-mill and 42 isolates from the dry-grind facility were tested for antimicrobial susceptibility using
broth dilution and agar dilution methods. In general, the Lactobacillus isolates from the dry-grind plant had higher minimum inhibitory concentrations (MICs) for the tested agents than the isolates
from the wet-mill facility. The MIC90 for VIR was 4 μg/ml for the dry-grind isolates versus 0.25 μg/ml for the wet-mill isolates; and for PEN, the MIC90’s were >8 and 2 μg/ml for the dry-grind and wet-mill isolates, respectively. Sixteen Lactobacillus isolates from the dry-grind plant but none from the wet-mill possessed vatE, a gene that encodes a streptogramin acetyltransferase associated with resistance to virginiamycin. Despite decreased susceptibility
to virginiamycin, most dry-grind isolates had MICs lower than the maximal recommended application rate of 6 ppm.
Mention of a trade name, proprietary product, or specific equipment does not constitute a guarantee or warranty by the United
States Department of Agriculture and does not imply its approval to the exclusion of other products that may be suitable. 相似文献
19.
Cui J Goh KK Archer R Singh H 《Journal of industrial microbiology & biotechnology》2007,34(5):393-402
The protein-bound polysaccharides of Coriolus versicolor (CPS) have been reported to stimulate overall immune functions against cancers and various infectious diseases by activating
specific cell functions. A New Zealand isolate (Wr-74) and a patented strain (ATCC-20545) of C. versicolor were compared in this study. The fruit bodies of both strains were grown for visual verification. Both strains were grown
in submerged-culture using an airlift fermentor with milk permeate as the base medium supplemented with glucose, yeast extract
and salt. Metabolic profiles of both strains obtained over 7-day fermentation showed very similar trends in terms of biomass
production (8.9–10.6 mg/ml), amounts of extracellular polysaccharide (EPS) from the culture medium (1150–1132 μg/ml), and
intracellular polysaccharide (IPS) from the mycelium (80–100 μg/ml). Glucose was the dominant sugar in both EPS and IPS, and
the polymers each consisted of three molecular weight fractions ranging from 2 × 106 to 3 × 103 Da. Both the EPS and IPS were able to significantly induce cytokine production (interleukin 12 and γ interferon) in murine
splenocytes in vitro. Highest levels of interleukin 12 (291 pg/ml) and γ interferon (6,159 pg/ml) were obtained from samples
containing Wr-74 IPS (0.06 μg/ml) and ATCC 20545 IPS (0.1 μg/ml), respectively. The results indicated that lower levels of
EPS and IPS generally resulted in higher immune responses than did higher polymer concentrations. 相似文献
20.
F. W. Wang Z. M. Hou C. R. Wang P. Li D. H. Shi 《World journal of microbiology & biotechnology》2008,24(10):2143-2147
The metabolites of endophytic fungus Penicillium sp. from the leaf of Hopea hainanensis were reported for the first time. By bioassay-guided fractionation, the EtOAc extract of a solid-matrix steady culture of
this fungus afforded six compounds, which were identified through a combination of spectral and chemical methods (IR, MS,
1H- and 13C-NMR) to be monomethylsulochrin (1), rhizoctonic acid (2), asperfumoid (3), physcion (4), 7,8-dimethyl-iso-alloxazine (5) and 3,5-dichloro-p-anisic acid (6). Compounds 2, 3 and 6 were obtained from Penicillium sp. for the first time. All of the six isolates were subjected to in vitro bioactive assays including antifungal action against
three human pathogenic fungi Candida albicans, Trichophyton rubrum and Aspergillus niger and cytotoxic activity against the human nasopharyngeal epidermoid tumor KB cell line and human liver cancer HepG2 cell line.
As a result, compounds 2–4 and 6 inhibited the growth of C. albicans with MICs of 40.0, 20.0, 50.0 and 15.0 μg/ml, respectively and the compound 6 showed growth inhibition against A. niger with MICs of 40.0 μg/ml. In addition, compounds 1–3 and 6 exhibited cytotoxic activity against KB cell line with IC50 value of 30.0, 20.0, 20.0, 5.0 μg/ml, respectively and against HepG2 cell line with IC50 value of 30.0, 25.0, 15.0, 10.0 μg/ml, respectively. 相似文献