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1.
Previous experiments indicated that water extracts of lambsquarters (Chenopodium album) and green foxtail (Setaria viridis), among others, stimulated growth of Bradyrhizobium japonicum in broth culture. Water extracts of lambsquarters shoots collected before or after anthesis were equally stimulatory. The stimulatory effect of extracts of lambsquarters when heated to 100°C for 30 min or autoclaved for 15 min was reduced by about 20% compared to untreated extracts. Extracts of green foxtail were less affected by higher temperature under similar conditions. Extracts of both green foxtail and lambsquarters completely lost their stimulatory effect following exposure to aerial microflora for 120 h. Water extract of lambsquarters shoots was more stimulatory than methanol extract, and neither ether nor butanol extracts resulted in stimulation. Both shoots and roots of lambsquarters and green foxtail were sequentially extracted first by water followed by methanol and vice-versa. The bioassay of these extracts indicated that there could be two components of the growth factor-one, larger component is soluble in water, the other, smaller component is soluble in methanol. After fractionation of the crude aqueous extract of lambsquarters shoots by four organic solvents, the residual aqueous extract retained the growth factor. Dialysis of the residual aqueous extract of lambsquarters shoots through a membrane (MWCO 1000) indicated that the molecular weight of the growth factor was less than 1000. The fraction having molecular weight <1000 was separated by paper chromatography using 6% acetic acid as developer. The fraction with Rf 0.91 showed the highest stimulation of the bacterium. 相似文献
2.
Water extracts of shoot of common lambsquarters (Chenopodium album), yellow nutsedge (Cyperus esculentus) and sunflower (Helianthus annuus) at 1% level significantly reduced soybean seed germination. Soybean seedlings inoculated with broth culture of nodule bacterium were grown for 25 days in N-free nutrient solution amended with cold water extracts of weed residues at 1 and 2% levels. At both levels extracts from residues of all weeds except that of lambsquarters enhanced growth of soybean. Nodulation was generally stimulated by the extracts of five weeds at 1% level except that of lambsquarters. Extracts from lambsquarters at 2% level completely suppressed and at 1% level reduced nodulation by 60%. Extracts from green foxtail (Setaria viridis), Pennsylvania smartweed (Polygonium pensylvanicum) and sunflower at 2% level reduced and at 1% level enhanced nodulation. The residues of lambsquarters shoot incorporated with soil at 0.5 and 1% levels caused 85 and 96% reduction respectively in seed germination and those of Pennsylvania smartweed and sunflower at 1% reduced seed germination by 40–70% but not at 0.5% level. The residues of foxtail and smartweed at both levels enhanced growth and nodulation. Under similar conditions nutsedge at 1% level stimulated nodulation but not growth. The residues of lambsquarters at both levels were inhibitory to nodulation but stimulated growth at 0.5% level. 相似文献
3.
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
4.
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
5.
Ping Su Anders Henriksson Christina Nilsson Hazel Mitchell 《World journal of microbiology & biotechnology》2008,24(9):1837-1842
The aim of this study was to assess the effect of a commercial green tea extract (TEAVIGO™) on the microbial growth of three
probiotic strains (Lactobacillus and Bifidobacterium), as well as three pathogenic bacteria. MIC and co-culture studies were performed. The MICs of the green tea extract against
Staphylococcus aureus and Streptococcus pyogenes (100 μg ml−1) were considerably lower than those against the probiotic strains tested (>800 μg ml−1) and Escherichia coli (800 μg ml−1). In co-culture studies, a synergistic effect of the probiotic strains and the green tea extract was observed against both
Staph. aureus and Strep. pyogenes. Green tea extract in combination with probiotics significantly reduced the viable count of both pathogens at 4 h and by
24 h had completely abolished the recovery of viable Staph. aureus and Strep. pyogenes. These reductions were more significant than the reductions induced by probiotics or green tea extracts used separately.
These results demonstrate the potential for combined therapy using the green tea extract plus probiotics on microbial infections
caused by Staph. aureus and Strep. pyogenes. As probiotics and the green tea extract are derived from natural products, treatment with these agents may represent important
adjuncts to, or alternatives to, conventional antibiotic therapy. 相似文献
6.
G. Selvakumar S. Kundu Piyush Joshi Sehar Nazim A. D. Gupta H. S. Gupta 《Indian journal of microbiology》2010,50(1):50-56
Exiguobacterium acetylicum strain 1P (MTCC 8707) is a gram-positive, rod-shaped, yellow pigmented bacterium isolated from soil on nutrient agar plates
at 4°C. The identity of the bacterium was arrived on the basis of the biochemical characterization, BIOLOG sugar utilization
pattern and sequencing of the 16S rRNA gene. It grew at temperatures ranging from 4 to 42°C, with temperature optima at 30°C.
It expressed multiple plant growth promotion attributes such as phosphate solubilization, indole acetic acid (IAA), siderophore
and hydrogen cyanide (HCN) production, differentially at suboptimal growth temperatures (15 and 4°C). At 15°C it solubilized
phosphate (21.1 μg of P ml−1 day−1), and produced IAA (14.9 μg ml−1 day−1) in tryptophan amended media. Qualitative detection of siderophore production and HCN were possible at 15°C. At 4°C it retained
all the plant growth promotion attributes. Seed bacterization with the isolate, positively influenced the growth and nutrient
uptake parameters of wheat seedlings in glass house studies at suboptimal cold growing temperatures. 相似文献
7.
G. Selvakumar S. Kundu Piyush Joshi Sehar Nazim A. D. Gupta P. K. Mishra H. S. Gupta 《World journal of microbiology & biotechnology》2008,24(7):955-960
Pantoea dispersa strain 1A is a Gram-negative rod-shaped, yellow-pigmented bacterium isolated on nutrient agar plates incubated at 4°C. The
identity of the bacterium was confirmed by sequencing of the 16 S rRNA gene. It was capable of growing at temperatures ranging
from 4 to 42°C, but maximum growth was observed at 30°C. It is endowed with multiple plant growth promotion attributes such
as phosphate solubilization, IAA production, siderophore production and HCN production, which are expressed differentially
at sub-optimal temperatures (15 and 4°C). It was able to solubilize phosphate (17.6 μg of P2O5 ml−1 day−1), and produce IAA (3.7 μg ml−1 day−1), at 15°C. Qualitative detection of siderophore production and HCN were also observed at 15°C. At 4°C it was found to express
all the plant growth promotion attributes. This bacterial isolate was able to positively influence and promote the growth
and nutrient uptake parameters of wheat (cv. VL.802) under glasshouse conditions. Hence in the context, of cold wheat-growing
environments, it is proposed that Pantoea dispersa 1A (MTCC 8706), could be deployed as an inoculant to attain the desired results of bacterization. 相似文献
8.
Under optimum conditions (pH 5, 75°C, and 0.2 U purified enzyme ml−1), 4 mg ginsenoside Rd was produced from 5 mg reagent-grade ginsenoside Rb1 in 5 ml after 30 min by β-glucosidase from Thermus caldophilus GK24. Using a ginseng root extract containing 1 mg ginsenoside Rb1 ml−1 and 3.2 mg additional ginsenosides ml−1, 1.23 mg ginsenoside Rd ml−1 was produced after 18 h; the concentrations of ginsenosides Rb1, Rb2, and Rc used for ginsenoside Rd production were 0.77, 0.17, and 0.19 mg ml−1, respectively. 相似文献
9.
The nature of the explant, seedling age, medium type, plant growth regulators, complex extracts (casein hydrolysate, coconut
milk, malt extract and yeast extract) and antioxidants (activated charcoal, ascorbic acid, citric acid and polyvinylpyrrolidone)
markedly influenced in vitro propagation of Gymnema sylvestre. A maximum number of shoots (57.2) were induced from 30 day old seedling axillary node explants on Murashige and Skoog (MS)
medium containing 6-benzyladenine (1 mg l−1), kinetin (0.5 mg l−1), 1-napthalene acetic acid (0.1 mg l−1), malt extract (100 mg l−1) and citric acid (100 mg l−1). High frequency of rooting was obtained in axillary node explant derived shoots (50%) on half strength MS medium supplemented
with IBA (3 mg l−1). The plantlets, thus developed, were hardened and successfully established in natural soil.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
10.
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
11.
Inhibition of galectin-3 mediated cellular interactions by pectic polysaccharides from dietary sources 总被引:1,自引:0,他引:1
Pectic polysaccharides from dietary sources such as Decalepis hamiltonii—swallow root (SRPP), Hemidesmus indicus (HPP), Nigella sativa—black cumin (BCPP), Andrographis serpyllifolia—(APP), Zingiber officinale—ginger (GRPP) and, citrus pectin (CPP) were examined for galectin inhibitory activity. Inhibition of (a) galectin-3 of MDA-MB-231
cells induced hemagglutination of red blood cells; (b) galectin-3 mediated interaction between normal/metastatic human buccal
cells (NBC)/(MBC) and; (c) invasion of MDA-MB-231 and MBC in the invasive chamber was assessed. Results indicated that SRPP
inhibited hemagglutination at Minimum Inhibitory Concentration (MIC) of 1.86 μg ml−1 equivalent of carbohydrate as apposed to those of BCPP (130 μg ml−1), APP (40 μg ml−1), HPP (40 μg ml−1) and CPP (25 μg ml−1). GRPP even at concentration >1–6 mg ml−1 did not inhibit agglutination. Also SRPP showed ∼15 and 2 fold potent anti hemagglutination activity relative to that of
galectin-3 specific sugars—galactose (MIC-27.1 μg ml−1) and lactose (MIC-4.16 μg ml−1) respectively. Further, SRPP at 10 μg ml−1 inhibited agglutination of NBC by galectin-3 of MDA-MB-231 cells. Modified swallow root pectic polysaccharide (MSRPP) of
50 kDa retained anti hemagglutination activity (MIC of 1.03 μg ml−1) and inhibited MDA-MB-231 and MBC invasion by 73 and 50% with an IC50 of 136 and 200 μg ml−1 respectively. Both SRPP and MSRPP induced apoptosis up to 80% at 100 μg ml−1 concentration by activating ∼2 and 8 folds of Caspase-3 activity. Sugar composition analysis and its correlation with the
galectin inhibitory property indicated that pectic polysaccharides with higher arabinose and galactose content—arabinogalactan
inhibited hemagglutination significantly. 相似文献
12.
The thermophilic bacterial strain MP4 assigned to a new species, likely of the genus Alicyclobacillus, was isolated from geothermal soils on the NW slope of Mount Melbourne, Antarctica. These soils have high iron concentrations
and the strain MP4 requires iron additions for growth. Four mesophilic bacterial strains Paenibacillus validus MP5, MP8, and MP10, and P. apiarius MP7, isolated from the same site, need iron supply for growth depending on the medium. Growth temperature of thermophilic
strain ranges from 42 to 70 °C, and that one of mesophiles from 25 to 44 °C. Thermophilic and mesophilic strains shared microenvironments
with temperature of 42–44 °C and showed optima of pH values ranging from 5.5 to 6.0. The thermophilic strain MP4 reached values
of 106 CFU ml−1 in aqueous soil extract from the NW slope of Mt. Melbourne, and 105 CFU ml−1 in water extracts from other geothermal Antarctic areas (Mt. Rittmann and Cryptogam Ridge). Growth of thermophilic bacteria
in aqueous extracts of the NW slope of Mount Melbourne soils caused a reduction of 50% of soluble iron content, which was
recovered in bacterial biomass. These results suggest a possible involvement of the thermophilic strain MP4 in iron bioavailability
in these geothermal soils. 相似文献
13.
HF Santana AA Barbosa SO Ferreira HC Mantovani 《World journal of microbiology & biotechnology》2012,28(2):485-491
Staphylococcus aureus is an important pathogen for both humans and animals, and it has been an ubiquitous etiological agent of bovine mastitis
in dairy farms worldwide. Elimination of S. aureus with classic antibiotics is difficult, and the current study aimed to evaluate the efficacy of ethanolic extracts of propolis
(EEP) against S. aureus cultivated in complex media or milk. EEP (0–0.5 mg ml−1) decreased growth of S. aureus in BHI media and 1 mg ml−1 was bactericidal against washed cell suspensions (107 CFU ml−1). Propolis extracts also killed S. aureus cells resuspended in milk, but the bactericidal dose was at least 20-fold greater. Cultures that were transferred for at
least 60 generations with sub-lethal doses of propolis did not change much their sensibility to EEP. Atomic force microscopy
images revealed changes in morphology and cell size of S. aureus cells exposed to EEP (0.5 mg ml−1). Our results indicate that propolis extracts might be effective against mastitis-causing S. aureus strains in vivo, but milk constituents affect the inhibitory activity of propolis. Considering that propolis-resistance appears
to be a phenotype not easily selected, the use of EEP combined or not with other antimicrobial agents might be useful for
mastitis control in vivo. 相似文献
14.
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
15.
Chávez-Quintal P González-Flores T Rodríguez-Buenfil I Gallegos-Tintoré S 《Indian journal of microbiology》2011,51(1):54-60
Bioactive compounds from vegetal sources are a potential source of natural antifungic. An ethanol extraction was used to obtain
bioactive compounds from Carica papaya L. cv. Maradol leaves and seeds of discarded ripe and unripe fruit. Both, extraction time and the papaya tissue flour:organic
solvent ratio significantly affected yield, with the longest time and highest flour:solvent ratio producing the highest yield.
The effect of time on extraction efficiency was confirmed by qualitative identification of the compounds present in the lowest
and highest yield extracts. Analysis of the leaf extract with phytochemical tests showed the presence of alkaloids, flavonoids
and terpenes. Antifungal effectiveness was determined by challenging the extracts (LE, SRE, SUE) from the best extraction
treatment against three phytopathogenic fungi: Rhizopus stolonifer, Fusarium spp. and Colletotrichum gloeosporioides. The leaf extract exhibited the broadest action spectrum. The MIC50 for the leaf extract was 0.625 mg ml−1 for Fusarium spp. and >10 mg ml−1 for C. gloeosporioides, both equal to approximately 20% mycelial growth inhibition. Ethanolic extracts from Carica papaya L. cv. Maradol leaves are a potential source of secondary metabolites with antifungal properties. 相似文献
16.
Hisashi Kato-Noguchi Madoka Yamamoto Kazuya Tamura Toshiaki Teruya Kiyotake Suenaga Yoshiharu Fujii 《Plant Growth Regulation》2010,60(2):127-131
Aqueous methanol extracts of rattail fescue (Vulpia myuros) inhibited the growth of roots and shoots of cress (Lepidium sativum), lettuce (Lactuca sativa), alfalfa (Medicago sativa), timothy (Phleum pratense), Digitaria sanguinalis and Lolium multiflorum. Increasing the extract concentration increased the inhibition, suggesting that rattail fescue may have growth inhibitory
substances and possess allelopathic potential. The aqueous methanol extract of rattail fescue was purified and two main inhibitory
substances were isolated and identified by spectral data as (−)-3-hydroxy-β-ionone and (+)-3-oxo-α-ionol. Both substances
inhibited root and shoot growth of cress at concentrations greater than 0.3 μM. The concentrations required for 50% growth
inhibition on root and shoot growth of cress, lettuce, alfalfa, timothy, D. sanguinalis and L. multiflorum were 2.7–19.7 μM for (−)-3-hydroxy-β-ionone, and 2.1–34.5 μM for (+)-3-oxo-α-ionol. The concentration of (−)-3-hydroxy-β-ionone
and (+)-3-oxo-α-ionol, respectively, in rattail fescue was 7.8 and 3.7 μg g−1 fresh weight. Considering the endogenous level and the inhibitory activity, (−)-3-hydroxy-β-ionone and (+)-3-oxo-α-ionol
may work as allelopathic substances in rattail fescue through the growth inhibition of neighboring plant species. 相似文献
17.
Effects of the invasive plant Mikania micrantha H.B.K. on soil nitrogen availability through allelopathy in South China 总被引:1,自引:0,他引:1
Allelopathy has been regarded as a mechanism for successful exotic plant invasion. However, it is not clear if and what effects
of allelopathic substances may exert on soil nutrient. The exotic plant Mikania micrantha H.B.K. (M. micrantha) has invaded many forests in south China, and recent studies have suggested it has allelopathic potential for other plants
and soil microbial community. Thus, we hypothesized that M. micrantha could influence soil nutrients and N transformation through allelopathy. We measured total C and N, NO3
−, NH4
+ and pH of the soil beneath M. micrantha and the adjacent open soil, and then measured the above soil properties after treating soil with 3 concentrations of aqueous
extracts of M. micrantha (T1: 0.005 g ml−1; T2: 0.025 g ml−1; T3: 0.100 g ml−1). In addition, a bioassay was conducted to determine the allelopathic potential of the soil beneath M. micrantha. The results showed that M. micrantha significantly affected soil nutrients and N transformation. Soil beneath M. micrantha had inhibitory effects on seed germination and seedling growth of test plant, and had significantly higher C, N, ammonia,
net nitrification rate than those of open soil. The plant extracts decreased soil pH, and T1 decreased it the most, and it increased soil C and N, and T1 represented the greatest increase in both C and N. The extracts also increased both NO3
− and NH4
+ in soil, whereas no significant difference existed among the 3 extract treatments. Compared to the water control, the soil
net mineralization rate was higher under T1, while lower under T2 and T3. However, the extracts increased the soil nitrification rates under all the treatments (T1, T2 and T3). Our results suggest that the water soluble allelochemicals of M. micrantha improve soil nutrient availability, through which the invasive plant M. micrantha may successfully invade and establish in new habitats. 相似文献
18.
The effect of several plant growth regulators on the number of tumors developing on potato tuber discs (Solatium tuberosum L. cv. Radka) inoculated withAgrobacterium tumefaciens, strain C 58 was studied. The plant growth regulators used in appropriate range of concentrations stimulated the formation
of tumors byA. tumefaciens.
Naphthaleneacetic acid (NAA) was most active in concentration of 10−4 mg ml−1. Kinetin gave a biphasic response with optimal promotions of tumor initiation at 10−4 − 2 × 10−3 mg ml−1. High kinetin concentration (10−1 mg ml−1) inhibited the formation of tumors completely. Indoleacetic acid (IAA) stimulated the initiation of tumors in the same range
of concentrations as kinetin, except that very high concentrations did not inhibit but enhanced tumor formation. 2,4-diehlorphenoxyacetic
acid (2,4-D) showed a biphasic response with maxima in 10−4 mg ml−1 and 10−1 mg ml−1. All the tumors scored for nopaline production showed nopaline synthase activity independently whether their formation was
stimulated by l0−1 mg ml−1 IAA or they were initiated without any treatment by plant growth regulators. 相似文献
19.
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
20.
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