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1.
Tonya D. Mitchell Ajmer S. Bhagsari Peggy Ozias-Akins Sarwan K. Dhir 《In vitro cellular & developmental biology. Plant》1998,34(4):319-324
Summary Transient expression of the β-glucuronidase (GUS) gene has been studied in leaf-derived embryogenic callus of sweetpotatoIpomoea batatas L. (Lam.) by electroporation. The influence of several factors including electric field strength, buffer composition, time
course of transientGUS gene expression, DNA concentration, enzyme, and polyethylene glycol (PEG) treatment was examined onGUS gene expression (number of blue spots). MaximumGUS gene expression (an average of 90 blue spots/fifty mg fresh weight callus tissue) was observed after 48 h when callus pieces
were preincubated with electroporation (EPR) buffer for 1 h, followed by electroporation with a single electric pulse of 500
V/cm discharged from a 960-μF capacitor in the presence of 20 μg DNA/ml and 8.3 μl NaCl (3M). Changing the electroporation buffer conductivity (by varying the buffer composition with low-high salt concentrations),
had only slight effect on the number of blue spots. Similarly, the time course study ofGUS gene expression revealed that GUS activity could be detected 12 h after electroporation with a maximum activity after 72
h (112 blue spots). Increasing the amount of DNA from 5 to 50 μg/ml in the EPR buffer had a slight effect on the expression
frequency (from 20–110 blue spots, and 112 blue spots with 20 μg/ml). The number of blue spots was increased by enzymatic
wounding of callus pieces for 10 min and by addition of 200 μl PEG 4000 (15%) before electroporation. These results suggest
that intact cell electroporation can be used for producing transgenic sweetpotato tissue. 相似文献
2.
The observations that liveMycobacterium leprae after entry into cultured peritoneal macrophages from mice, reduced the EA rosetting macrophages, have been exploited to
determine the minimum inhibitory concentration of diamino diphenyl sulphone and rifampicin. Diamino diphenyl sulphone showed
a minimum inhibitory concentration of 0.028 μg/ml and rifampicin 0.11μg/ml when given externally. However, there was accumulation of diamino diphenyl sulphone inside the macrophages. At an external
concentration of 0.028 μg/ml the concentration inside the macrophage was 0.5μg/ml. The minimum inhibitory concentration for diamino diphenyl sulphone in this assay system is higher by several folds and
that for rifampicin is slightly lower, than what is reported earlier with mice foot pad experiments. The minimum inhibitory
concentration reported in this assay system is quite close to what is observed forin vitro inhibition ofMycobacterium lufu with both the drugs 相似文献
3.
Camptothecin-resistant fungal endophytes of <Emphasis Type="Italic">Camptotheca acuminata</Emphasis>
Concentrations of the DNA topoisomerase I inhibitor camptothecin were determined in different tissues of Camptotheca acuminata (Nyssaceae). The data were dependent on tissue type and developmental stage. Despite the presence of the toxic compound camptothecin,
nine endophytic fungi were isolated from healthy C. acuminata plants and were tested for their camptothecin sensitivity. Two isolates showed almost no inhibition at a camptothecin concentration
of 10 μg/ml. Even at a concentration of 100 μg/ml the inhibition was moderate. 相似文献
4.
Extracts fromshiitake (Lentinula edodes) mycelial culture broth, by an organic solvent ethyl acetate, inhibited the proliferation of cultured cells. At lower concentrations
(1.25–15 μg/ml), this inhibition, measured by the MTT assay, was dose- and cell line-dependent. Inhibition of tumor cells,
such as Caski, SiHa, HeLa, HP-1 and A375, byL. edodes-436 extracts was stronger than inhibition of normal cells (3T3). At 20 μg/ml, the extracts induced changes in cell shape,
DNA-fragmentation and the activation of caspase-3. The extracts also inhibited the binding of E2F protein to its promoter.
The results suggest that extracts ofL. edodes culture broth contain substances that have the ability to induce apoptosis in the cultured cells. 相似文献
5.
In the present study, a simple one medium formulation protocol for callus culture, somatic embryogenesis and in vitro production
of β-carboline alkaloids and diosgenin in Tribulus terrestris L. was developed. Extensive callus induction and proliferation was obtained in leaf explant on Murashige and Skoog (MS) medium
supplemented with 5.0 μM 6 benzyl adenine (BA) and 2.5 μM α-naphthaleneacetic acid (NAA). The embryogenic callus was maintained
on subculture to fresh parental medium at 4-week intervals over a period of 28 months. The frequency of embryo formation was
at a maximum (18.1 ± 0.9 per g of callus) on MS medium containing 5.0 μM BA and 2.5 μM NAA together with 75 mg l−1 casein hydrolysate. Globular embryo developed into torpedo stage embryo under the influence of starvation. The accumulation
of β-carboline alkaloids (harmaline and harmine) and steroidal saponin (diosgenin) in non-embryogenic and embryogenic callus
culture derived from leaf explant was compared with root, leaf, stem, and fruit of the mother plant. The embryogenic callus
accumulated equivalent amounts of harmaline (66.4 ± 0.5 μg/g dry weight), harmine (82.7 ± 0.6 μg/g dry weight), and diosgenin
(170.7 ± 1.0 μg/g dry weight) to that of the fruit of T. terrestris. The embryogenic callus culture of this species might offer a potential source for production of important pharmaceuticals. 相似文献
6.
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
7.
Varsha Shriram Vinay Kumar Mahadeo G. Shitole 《In vitro cellular & developmental biology. Plant》2008,44(3):186-193
Abstract
Helicteres isora is a medicinal plant effective against asthma, diabetes, hypolipidemia, HIV, polio besides a good source of diosgenin. Seed
dormancy and low natural fruit production rate make this plant a perfect candidate for developing an in vitro regeneration
method. However, to date, no such work has been procured in this plant. An efficient method for plant regeneration via shoot
organogenesis from callus cultures has been developed using nodal explants in H. isora. Murashige and Skoog (MS) media counting 2,4-Dichlorophenoxyacetic acid (2,4-D, 2.26 to 13.57 μM), Indole-3-acetic acid (IAA,
2.85 to 17.13 μM), Indole-3-butyric acid (IBA, 2.46 to 14.70 μM), 6-Benzylaminopurine (BA, 2.22 to 13.32 μM) and Kinetin (Kin,
2.32 to 13.92 μM) either singly or in the following combinations (IAA + BA; IAA + Kin, and BA + Kin) produced granular callus
except BA + Kin which resulted in compact, hard, greenish-white (CHGW) callus. The optimum CHGW callus (2.62 g fresh weight/
explant) was produced on MS media with 13.32 μM BA + 2.32 μM Kin with over 93% callus induction frequency. Optimum shoot organogenesis
(67% frequency) was achieved in CHGW callus with lower level of BA (2.22 μM) and Kin (2.32 μM) and produced 3.2 shoots/0.5 g
callus within 35 d of culture. Microshoots were rooted successfully (62% frequency) after 35 d of culture on 1/2MS containing
4.90 μM IBA and hardened off. Antioxidant enzymes such as catalase, peroxidase, polyphenol oxidase, and biochemical parameters
viz. hydrogen peroxide, reducing and nonreducing sugars, starch, proteins, phenols, and proline contents were studied in regenerating
and nonregenerating CHGW calluses to establish a correlation between these parameters and shoot morphogenesis. All the enzyme
activities and biochemical parameters were found more in regenerating callus than in nonregenerating except phenols. 相似文献
8.
A. Oren 《Archives of microbiology》1996,165(5):354-358
Many members of the Halobacteriaceae are inhibited by quinolone compounds, which inhibit type II DNA topoisomerase. Ciprofloxacin
was the most potent inhibitor, followed by ofloxacin and norfloxacin. Ciprofloxacin concentrations between 25 and 60 μg/ml
caused 50% inhibition of the growth of most Haloferax and Haloarcula species. Halobacterium species were less sensitive. At sublethal concentrations, formation of elongated and/or swollen cells was observed in many
species. The alkaliphilic Natronobacterium pharaonis was very sensitive (50% inhibition by ciprofloxacin, ofloxacin, and norfloxacin at concentrations between 4 and 15 μg/ml).
The resistance of many members of the Halobacteriaceae to high concentrations of quinolone compounds may in part be due to
the high magnesium concentrations present in the growth media. Haloferax volcanii was sensitive to 40 μg/ml ciprofloxacin when grown at suboptimal magnesium concentrations (0.1 M), but was hardly affected
by 100 μg/ml of the inhibitor when grown in the presence of 0.5–0.75 M MgCl2. It is suggested that the putative archaeal type II DNA topoisomerase has properties similar to those of the enzyme from
Bacteria, although its sensitivity to quinolone antimicrobial compounds may be lower.
Received: 6 November 1995 / Accepted: 26 February 1996 相似文献
9.
Crown and leaf slices of in vitro plantlets of a non-flowering Vetiveria zizanioides from Java were used to induce compact calli and to regenerate plantlets. The influence of different growth regulators (2,4-dichlorophenoxy
acetic acid, 6-benzylaminopurine), sucrose concentrations (10–100 g l−1), cultivation in light or dark, and cultivation time on callus induction medium (6 or 12 weeks), on the induction of compact
callus and the subsequent regeneration of plantlets was studied. Up to 75% of crown slices cultured on modified Murashige
and Skoog medium supplemented with 2.26 μM 2,4-dichlorophenoxy acetic acid, 2.22 μM 6-benzylaminopurine and 75 g l−1 sucrose developed compact callus. For subsequent regeneration of plantlets, callus induction in the light for 6 weeks on
the callus induction medium containing 10 g l−1sucrose, and subsequent transfer to the regeneration medium, was the best procedure, regenerating plantlets on around 60%
of the crown or leaf slices, with up to 100 plantlets per slice. We have compared the efficiency of the above mentioned procedure
with several other methods to regenerate plantlets. Our findings indicate that the procedure developed in this study was best
in regenerating plantlets for the used vetiver variant.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
10.
We compared the effects of four quaternary benzo[c]phenanthridine alkaloids – chelerythrine, chelilutine, sanguinarine, and sanguilutine – and two quaternary protoberberine
alkaloids – berberine and coptisine – on the human cell line HeLa (cervix carcinoma cells) and the yeastsSaccharomyces cerevisiae andSchizosaccharomyces japonicus var. versatilis. The ability of alkaloids to display primary fluorescence, allowed us to record their dynamics and localization in cells.
Cytotoxic, anti-microtubular, and anti-actin effects in living cells were studied. In the yeasts, neither microtubules nor
cell growth was seriously affected even at the alkaloid concentration of 100 μg/ml. The HeLa cells, however, responded to
the toxic effect of alkaloids at concentrations ranging from 1 to 50 μg/ml. IC50 values for individual alkaloids were: sanguinarine IC50 = 0.8 μg/ml, sanguilutine IC50 = 8.3 μg/ml, chelerythrine IC50 = 6.2 μg/ml, chelilutine IC50 = 5.2 μg/ml, coptisine IC50 = 2.6 μg/ml and berberine IC50 >10.0 μg/ml. In living cells, sanguinarine produced a decrease in microtubule numbers, particularly at the cell periphery,
at a concentration of 0.1 μg/ml. The other alkaloids showed a similar effect but at higher concentrations (5–50 μg/ml). The
strongest effects of sanguinarine were explained as a consequence of its easy penetration through the cell membrane owing
to nonpolar pseudobase formation and to a high degree of molecular planarity.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
11.
G. A. Moore M. J. Miller Kenneth Cline 《In vitro cellular & developmental biology. Plant》1988,24(12):1205-1208
Summary The effects of the antibiotics methotrexate and chloramphenicol on somatic embryogenesis inCitrus were evaluated. Relatively low levels (0.1 to 1.0 μg/ml) of these antibiotics did not inhibit embryo production from undeveloped
ovules of ‘Key’ lime [C. aurantifolia) (Christm.) Swing.]. Surprisingly, both antibiotics induced the formation of embryogenic callus in these cultures. This is
usually a rare event in cultures of undevelopedCitrus ovules, and ‘Key’ lime is especially recalcitrant. The effects of these antibiotics on embryogenic callus appeared to be
limited to the induction stage, because there was no consistent effect, either stimulatory or inhibitory, on established,
lines of embryogenic callus.
Florida Agricultural Experiment Station Journal Series No. 8958. This research was supported in part by a grant to Moore and
Cline from the Competitive Grants Office of the SEA, USDA (85-CRCR-1-1623). 相似文献
12.
Karla K. Valenzuela-Sánchez Raul E. Juárez-Hernández Andrés Cruz-Hernández Víctor Olalde-Portugal María Elena Valverde Octavio Paredes-Lopez 《In vitro cellular & developmental biology. Plant》2006,42(4):336-340
Summary Indirect organogenesis was developed in Agave tequilana. Leaf segments and meristematic tissue from the central head (‘pi?a’) were evaluated as explant sources. A minimal-sized
explant with high bud-forming capacity (19.5 BFC) was obtained through a cross section of meristematic tissue from in vitro plantlets. In callus culture, the best growth response was due to naphthalene acetic-acid (NAA) presenting a contrasting
response compared to 2,4-dichlorophenoxyacetic acid (2,4-D). Regeneration from meristem segments and callus was obtained using
1.1 μM 2,4-D and 44 μM 6-benzylaminopurine (BA). The regeneration capacity of callus was maintained for 3 mo. Shoots regenerated were rooted in
a hormone-free MSI medium and acclimatized in a greenhouse with a 100% survival. 相似文献
13.
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
14.
Antimicrobial Butyrolactone I Derivatives from the Ecuadorian Soil Fungus Aspergillus terreus Thorn. var terreus 总被引:1,自引:0,他引:1
M. E. Cazar G. Schmeda-Hirschmann L. Astudillo 《World journal of microbiology & biotechnology》2005,21(6-7):1067-1075
Summary The fungus Aspergillus terreus Thorn var. terreus isolated from an Ecuador soil sample was cultured in liquid and solid media and yielded three main metabolites identified
as terreic acid (1), butyrolactone I (2) and lovastatin (3). The natural products as well as three synthetic butyrolactone I derivatives were assessed for antimicrobial activity against
Gram-positive and Gram-negative bacteria and fungi as well as for seed germination and seedling growth. Furthermore, the compounds
were assessed as inhibitors towards the enzymes acetylcholinesterase, β-glucosidase, and β-glucuronidase. Terreic acid, butyrolactone I, butyrolactone 4′,4′′-diacetate (2.1), and 3′-(3-methylbutyl)-butyrolactone II (2.2) were active towards the phytopathogenic bacteria Erwinia carotovora with IC50 of 5 and 4–18 μg/ml, respectively. Under the same experimental conditions, the IC50 of streptomycin was 1.9 μg/ml. 3′-(3-Methylbutyl)-butyrolactone II was moderately active against Pseudomonas syringae and Botrytis cinerea with IC50 of 21μg/ml and MIC of 15.6 μg/ml, respectively. Butyrolactone I also inhibited germination of the dicot Lactuca sativa with an IC50 of 5 × 10−5 M. The IC50 of reference herbicide acetochlor was 1 × 10−5 M. The effect of 2.2 and 2.3, known as butyrolactone III on Panicum millaceum germination and growth was stronger than that of 2 and 2.1. Reduction of the double bond in the isoprenyl side chain of butyrolactone I increased the antibacterial effect against E. carotovora as well as acetylation. To our best knowledge, this is the first report on the antibacterial effect of butyrolactone derivatives
towards Erwinia carotovora and the phytopathogenic fungus Botrytis cinerea. The butyrolactone I derivative 2.2 presented a moderate inhibitory effect against the enzyme acetylcholinesterase with an IC50 of 47 μg/ml. Under the same experimental conditions, the reference inhibitor galanthamine had an IC50 of 3 μg/ml. 相似文献
15.
Manickam V.S. Elango Mathavan R. Antonisamy R. 《Plant Cell, Tissue and Organ Culture》2000,62(3):181-185
The development of stem callus mediated plant regeneration system for Withania somnifera is described. Maximum callus proliferation was obtained on Murashige and Skoog medium supplemented with 2.26 μM 2,4-D. Three-week-old,
white, friable callus was used for shoot regeneration. The maximum shoot regeneration (6.2 ± 0.34 shoots/explant) was achieved
in four weeks when callus was cultured on MS medium fortified with 4.44 μM BA and 0.57 μM IAA. Regenerated shoots were excised
and multiplied (8.4 ± 0.43 shoots/explant) on MS medium supplemented with 4.44 μM of BA. Multiple shoots were divided into
single shoots and were rooted (5.1 ± 0.49 rootlets/shoot) on half strength MS medium supplemented with 9.84 μM of IBA. After
a hardening phase of 3 weeks the plantlets were transferred to the field.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
16.
D. J. Williams K. H. Al-Juboory R. M. Skirvin 《In vitro cellular & developmental biology. Plant》1998,34(4):289-292
Summary The objective of this study was to evaluate the ability ofHosta Golden Scepter (GS) ovary explants to generate adventitious shootsin vitro. Ovaries were transversely cut into halves and transferred to petri dishes containingHosta initiation medium supplemented with naphthaleneacetic acid (NAA) at 2.5 μM and N6-benzyladenine (BA) at 10 μM. GS produced adventitious shoots from the ovary base via organogenesis. The number of adventitious shoots regenerated from
callus increased linearly with repeated subculturing on Murashige and Skoog (MS) medium supplemented with 2.5 μM NAA and 10 μM BA. The number of multiple shoots developing from callus (15.8), shoot tip (8.4), leaf (6.7), and root (4.3) occurred on
MS medium supplemented with 2.5 μM NAA and 20–30 μM BA. There were significant differences in the number of shoots regenerated from shoot tips and callus on MS medium with 50
and 100 mgmyo-inositol per l. Similarly, there were significant differences in the number of axillary shoots and adventitious shoots produced
with 20 g/l sucrose treatment. 相似文献
17.
Kang SK Kim KS Byun YS Suh SJ Jim UH Kim KH Lee IS Kim CH 《In vitro cellular & developmental biology. Animal》2006,42(7):225-229
Summary
Ulmus davidiana Planch (Ulmaceae) (UD) long has been known to have anti-inflammatory and protective effects on damaged tissue, inflammation,
and bone among other functions. The herbal medicine also is being used in Oriental medicine to treat osteoporosis. In a preliminary
study, treatment of osteoclasts containing long bone cells with the water extract of UD bark prevented the intracellular maturation
of cathepsin K (cat K), and thus, it was considered that UD is a pro-drug of a potent bone-resorption inhibitor. To further
clarify the role of UD in ossification, we investigated the effects of UD on the proliferation and differentiation of osteoblastic
cell lines in vitro. In this study, we assessed the effects of UD on osteoblastic differentiation in nontransformed osteoblastic
cells (MC3T3-E1) and rat bone marrow cells. UD enhanced alkaline phosphatase (ALP) activity and mineralization in a dose-
and time-dependent fashion. This stimulatory effect of the UD was observed at relatively low doses (significant at 5–50 μg/ml
and maximal at 50 μg/ml). Northern blot analysis showed that UD (100 μg/ml) increases in bone morphogenic protein-2 as well
as ALP mRNA concentrations in MC3T3-E1 cells. UD slightly increased in type I collagen mRNA abundance throughout the culture
period, whereas it markedly inhibited the gene expression of collagenase-1 between days 15 and 20 of culture. These results
indicate that UD has anabolic effects on bone through the promotion of osteoblastic differentiation, suggesting that is could
be used for the treatment of common metabolic bone diseases such as osteoporosis. 相似文献
18.
Masayoshi Ono John W. Perry Takami Oka 《In vitro cellular & developmental biology. Plant》1981,17(2):121-128
Summary Cortisol was previously shown to elicit a concentration-dependent inhibition of α-lactalbumin accumulation in midpregnant
mouse mammary gland cultured in medium containing optimal concentrations of 5 μg/ml prolactin and insulin. In contrast, casein
accumulation under these conditions was progressively stimulated by addition of increasing amounts of cortisol (Ono, M.; Oka,
T. Cell 19: 473–480; 1980). In the present study we found that in the presence of a suboptimal concentration of 0.5 μg/ml
prolactin, 2.8×10−9
M to 2.8×10−7
M cortisol stimulated α-lactalbumin accumulation. Furthermore, higher concentrations of cortisol produced a smaller inhibition
of α-lactalbumin accumulation as compared to that obtained in cultures containing 5 μg/ml prolactin. The maximal increase
in α-lactalbumin accumulation attained in the presence of 1.4×10−8
M cortisol, 0.5 μg/ml prolactin, and insulin was comparable to that observed in culture containing 5 μg/ml prolactin and insulin.
Similar results were obtained in a cortisol concentration-response study of α-lactalbumin accumulation in cultures containing
a suboptimal concentration of 0.5 μg/ml human placental lactogen. Measurement of the rate of α-lactalbumin synthesis in cultured
tissue indicated that the opposing effects of low and high concentrations of cortisol on α-lactalbumin accumulation involved
an alteration in the rate of synthesis of the milk protein. In contrast to α-lactalbumin, the synthesis of casein was stimulated
in a concentration-dependent manner by addition of cortisol that acted synergistically with either 0.5 μg/ml or 5 μg/ml prolactin.
The maximal increases were obtained in the presence of 2.8×10−6
M cortisol. These results indicated that the action of cortisol on α-lactalbumin accumulation can be modulated by the concentration,
of prolactin and suggest that the interplay between cortisol and prolactin in regulation of α-lactalbumin synthesis may be
different from that involved in casein synthesis. 相似文献
19.
The hexane, ethyl acetate, dichloromethane, methanol extracts and spent media (extracellular substances) were tested in vitro
for their antibacterial activity for which one Gram-positive bacterium (Staphylococcus aureus) and four Gram-negative bacteria
(Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, and Klebsiella pneumoniae) were used as test organisms. The methanol
extract showed more potent activity than other organic extracts, spent medium of the culture exhibited little activity against
E. coli only. No inhibitory effect was found against Klebsiella pneumoniae.The broth microdilution assay gave minimum inhibitory
concentrations (MIC) values ranging from 1 to 512 μg/ml. The MIC of methanol extract against S. aureus and E. coli were 128
μg/ml and 256 μg/ml, respectively. 相似文献
20.
Alma R. López-Laredo Fanny D. Ramírez-Flores Gabriela Sepúlveda-Jiménez Gabriela Trejo-Tapia 《In vitro cellular & developmental biology. Plant》2009,45(5):550-558
Tecoma stans is a tropical plant from the Americas. Antioxidant activity and both phenolic compound and flavonoid total content were determined
for callus tissue of T. stans cultured in either a set photoperiod or in darkness. Callus lines from three explant types (hypocotyls, stem, and leaf) were
established on B5 culture medium supplemented with 0.5 μM 2,4-D and 5.0 μM kinetin. While leaf-derived callus grew slower
under a 16-h photoperiod (specific growth rate, μ = 0.179 d−1, t
D = 3.9 d) than in darkness (μ = 0.236 d−1, t
D = 2.9 d), it accumulated the highest amount (p < 0.05) of both phenolics (86.6 ± 0.01 mg gallic acid equivalents/g) and flavonoids (339.6 ± 0.06 mg catechin equivalents/g).
Similarly, antioxidant activity was significantly higher (p < 0.05) when callus was cultured in period light than when grown in extended darkness. Antioxidant activity measured with
a 2,20-azinobis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS)-based assay was 350.5 ± 15.8 mmol Trolox/g
extract for callus cultured under a defined photoperiod compared to 129.1 ± 7.5 mmol Trolox/g extract from callus cultured
in darkness. Content of phenolic compounds and flavonoids was in agreement with a better antioxidant power (EC50 = 450 μg extract/mg 1,1-diphenyl-2-picrylhydrazyl) and antiradical efficiency. Results of the present study show that calli
of T. stans are a source of compounds with antioxidant activity that is favored by culture under a set photoperiod. 相似文献