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1.
María del Socorro Santos Díaz Candy Carranza Álvarez 《In vitro cellular & developmental biology. Plant》2009,45(2):162-170
Two procedures for the in vitro propagation of Encyclia mariae, a threatened Mexican orchid, were developed. In the first procedure, leaves from in vitro germinated seedlings were cultured on Murashige and Skoog medium (MS) supplemented with the range of 2.21–4.4 μM 6-benzylaminopurine
(BA) in combination with 2.69–10.74 μM naphthalene acetic (NAA), 2.07–8.29 μM indole-3-butyric (IBA), or 2.85–11.42 μM indole-3-acetic
acid (IAA) to determine the best medium for the induction of shooting. Maximum direct shoot formation from leaves was observed
on MS containing 22.21 μM BA and 10.74 μM NAA (25 shoots/explant). The second procedure began with the culture of protocorms
on media containing NAA, IBA, or IAA, which induced callus formation with high regenerative potential in the form of protocorm-like-bodies
(PLBs) that eventually differentiated into shoots. The optimal response was attained when these structures were cultured on
medium with 4.14 μM IBA (30 shoots/PLB). To promote the elongation of shoots derived from PLBs, the material was subcultured
onto MS medium containing 22.21 μM BA and 5.37 μM NAA. Through the exploration of the effects of auxins and matrix on the
rooting of shoots, it was determined that the optimal rooting occurred on media supplemented either with 5.71 μM IAA or 4.14 μM
IBA either on agar-gelled medium or in liquid media with coir as the matrix. Rooting was found to be 20% higher in liquid
media than in agar-gelled medium. 相似文献
2.
Xiaojiao Han Hongqiang Yang Kaixuan Duan Xinrong Zhang Haizhou Zhao Shuzhen You Qianqian Jiang 《Plant Cell, Tissue and Organ Culture》2009,96(1):29-34
The effects of sodium nitroprusside (SNP) on the multiplication, regeneration and rooting of Malus
hupehensis Rehd. var. pinyiensis Jiang in tissue culture have been investigated. The results showed that the multiplication of plantlets was promoted significantly
by applying 20 μM SNP to the Murashige and Skoog (MS) medium containing 2.0 μM 6-benzylaminopurine (BA) and 1.0 μM zeatin
(ZT). Multiplication of plantlets from the 1st subculture was more sensitive to SNP than that from the 4th or 7th subculture.
The differentiation and regeneration of adventitious shoots from leaves or cotyledons increased significantly when 20–30 μM
SNP was supplied to the medium MS containing 25 μM BA, 2.5 μM α-naphthaleneacetic acid (NAA) and 2.5 μM ZT. Adventitious shoots regeneration frequency from cotyledons was higher than that
from leaves at the presence of SNP. The rooting of plantlets was promoted by SNP significantly and the best result for rooting
was achieved in the half-strength MS medium containing 75 μM SNP. In addition, adventitious roots without callus distributed
at the base of shoots when SNP was supplied. 相似文献
3.
Two inhibitors, aviglycine and propargylglycine, were tested for their ability to suppress methionine synthesis thus inhibit
conidial germination and mycelial growth of Czapek-Dox liquid medium grown Fusarium oxysporum f. sp. luffae
μM. The linear inhibition range for mycelial growth was about 7.6–762.9 μM. Although aviglycine did not completely inhibit both conidial germination and mycelial growth, it showed significant inhibitory
effect at 1.5 μM. The inhibition range for propargylglycine against conidial germination and mycelial growth were from 0.08 to 8841 μM and from 0.8 to 884.1 μM, respectively. Propargylglycine inhibited conidial germination and mycelial growth at a concentration of 8841 μM. The EC50 values of aviglycine were 1 μM for conidial growth and 122 μM for mycelial growth, and the EC50 values of propargylglycine were 47.7 μM for conidial growth and 55.6 μM for mycelial growth. Supplement of methionine released inhibition of aviglycine or propargylglycine to conidial germination.
In addition, a mixture of aviglycine (1.5 μM) and propargylglycine (8841 μM) showed additive inhibitive effect than applied alone on 10 isolates. From these results, both aviglycine and propargylglycine
exhibited inhibitory activity, and suggest that they can provide potential tools to design novel fungicide against fungal
pathogens. 相似文献
4.
Susana Johann Daniele L. Silva Cleide V. B. Martins Carlos L. Zani Moacir G. Pizzolatti Maria A. Resende 《World journal of microbiology & biotechnology》2008,24(11):2459-2464
Plants are known to produce a plethora of secondary metabolites which are recognized as a useful source of new drugs or drug
leads. Extracts and fractions of Schinus terebinthifolius Raddi (Anacardiaceae), Piper regnellii C.D.C. (Piperaceae), Rumex acetosa L. (Polygonaceae), and Punica granatum L. (Punicaceae) were assessed for their antifungal activity against eight clinical isolates of C. albicans. They were also evaluated for their effect on the adhesion of these C. albicans isolates to buccal epithelial cells (BECs). The ethyl acetate fraction from the leaves of S. terebinthifolius showed promising activity, inhibiting the growth of three C. albicans isolates at 7.8 μg ml−1 and significantly inhibiting their adhesion to BEC at 15 μg ml−1
. In addition, this fraction did not show cytotoxic activity against murine macrophages. The results show the potential of
the plant extracts studied as a source of new antifungal compounds. Further studies are necessary for isolation and characterization
of the active compounds of these plants. 相似文献
5.
Sushma Tamta Lok Man S. Palni Vijay K. Purohit Shyamal K. Nandi 《In vitro cellular & developmental biology. Plant》2008,44(2):136-141
An efficient and reproducible method for the regeneration of multiple shoots of brown oak (Quercus semecarpifolia Sm.) has been developed in which a part of the petiolar tube containing a primary shoot is used as the explant. Explants
derived from in vitro grown seedlings were cultured either on Murashige and Skoog or Woody Plant medium (WPM) containing different concentrations
of benzyladenine (BAP) throughout the range of 1–20 μM. WPM supplemented with 20 μM BAP was found to be best for adventitious
shoot induction and for the multiplication of individual shoots. In-vitro-produced shoots were rooted using a two-step method. Firstly, shoots were cultured on WPM containing indolebutyric acid (IBA)
at either 50 or 100 μM for 24 or 48 h. Secondly, the shoots were transferred to plant-growth-regulator-free half-strength
WPM. The second step not only considerably improved the rooting percentage but also minimized the formation of basal callus.
The most effective first-step treatment was found to be 100 μM IBA for 24 h, which initiated rooting at a frequency of 100%.
Well-rooted plants were transferred to plastic cups containing nonsterile, sieved soil and farmyard manure, hardened under
greenhouse conditions, and then successfully established in pots. This procedure is suitable for use in large-scale production
of plants and may have potential application in additional oak species. 相似文献
6.
Abhishek Tripathi Neeta Sharma Vinay Sharma 《World journal of microbiology & biotechnology》2009,25(3):503-512
Hyptis
suaveolens L. (Poit.) essential oil was tested in vitro on the growth and morphogenesis of Fusarium oxysporum f.sp. gladioli (Massey) Snyder & Hansen, which causes Fusarium corm rot and yellows in various susceptible cultivars of gladiolus. The fungitoxicity of the oil was measured by percentage radial growth inhibition using the poisoned food technique (PF)
and volatile activity assay (VA). The mycelial growth of the test fungus was completely inhibited at 0.998 and 0.748 μg ml−1 concentration of oil in PF and VA, respectively. Essential oil was found to be fungicidal in nature at 1.247 and 0.998 μg ml−1 concentration of oil in PF and VA, respectively. Determination of conidial germination in the presence of oil was also carried
out and it was found that the oil exhibited 100% inhibition of conidial germination at 0.450 μg ml−1 concentration. The effect of essential oil on the yield of mycelial weight was observed and it was found that at 0.873 μg ml−1 concentration no mycelium was recorded and 100% inhibition was observed. The fungitoxicity of oil did not change even on
exposure to 100°C temperature or to autoclaving, and the oil also retained its fungicidal nature even after storage of 24 months.
The main changes observed under light microscopy after oil treatment were a decrease and loss of conidiation and anomalies
in the hyphae such as a decrease in the diameter of hyphae and granulation of cytoplasm. The treatment of the oil also showed
highly reduced cytoplasm in the hyphae, showing clear retraction of the cytoplasm from the hyphae and ultimately in some areas
hyphae without cytoplasm were also found. GC-MS studies of the essential oil revealed that the oil consisted of 24 compounds
with 1,8-cineole as major component accounting for 44.4% of the total constituents. 相似文献
7.
Raulio M Pore V Areva S Ritala M Leskelä M Lindén M Rosenholm JB Lounatmaa K Salkinoja-Salonen M 《Journal of industrial microbiology & biotechnology》2006,33(4):261-268
The aim of the present work was to explore possibilities of photocatalytic TiO2 coating for reducing biofilms on non-living surfaces. The model organism, Deinococcus geothermalis, known to initiate growth of durable, colored biofilms on machine surfaces in the paper industry, was allowed to form biofilms
on stainless steel, glass and TiO2 film coated glass or titanium. Field emission electron microscopy revealed that the cells in the biofilm formed at 45°C under
vigorous shaking were connected to the surface by means of numerous adhesion threads of 0.1--0.3 μm in length. Adjacent cells
were connected to one another by threads of 0.5--1 μm in length. An ultrastructural analysis gave no indication for the involvement
of amorphous extracellular materials (e.g., slime) in the biofilm. When biofilms on photocatalytic TiO2 surfaces, submerged in water, were exposed to 20 W h m−2 of 360 nm light, both kinds of adhesion threads were completely destroyed and the D. geothermalis cells were extensively removed (from >107 down to below 106 cells cm−2). TiO2 films prepared by the sol-gel technique were slightly more effective than those prepared by the ALD technique. Doping of
the TiO2 with sulfur did not enhance its biofilm-destroying capacity. The results show that photocatalytic TiO2 surfaces have potential as a self-cleaning technology for warm water using industries. 相似文献
8.
Stimulation of menthol production in <Emphasis Type="Italic">Mentha piperita</Emphasis> cell culture 总被引:1,自引:0,他引:1
Amrita Chakraborty Sharmila Chattopadhyay 《In vitro cellular & developmental biology. Plant》2008,44(6):518-524
Plant cell culture provides an alternative means for producing secondary metabolites. In this study, experiments were carried
out to study the impact of several parameters, independently and in combination, on the stimulation of menthol production
in the cell suspension culture of Mentha piperita. Callus was obtained from leaf segments of in vitro grown plantlets on Murashige and Skoog (MS) medium supplemented with 0.2 mg l−1of 2,4-dichlorophenoxy acetic acid to initiate cell suspension culture. This culture was maintained in half-strength MS medium
supplemented with 0.2 mg l−1of 2,4-dichlorophenoxy acetic acid at 15 d interval and used for further studies. Precursor feeding alone, i.e., menthone,
at 35 μM concentration showed slightly improved productivity. γ-Cyclodextrin alone at 60 μM concentration and in combination
with menthone feeding at 35 μM increased menthol yield up to 92 and 110 mg l−1 in comparison to 77 mg l−1 of control culture. Synergistic potentiation effect of menthone feeding at 35 μM and γ-cyclodextrin at 60 μM treatment followed
by in situ adsorption with RP-8 also showed potential stimulation of menthol production in M. piperita cell culture. Fungal elicitor treatment showed enhanced production level up to 140.8 mg l−1 in comparison to that of control. Further studies were carried out with the establishment of Agrobacterium tumefaciens (Ach5) gall-mediated calli, and consequently, cell suspension culture and results showed the significant enhancement of menthol
yield up to 278 mg l−1.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
9.
Jin Cui Jianjun Chen Richard J. Henny 《In vitro cellular & developmental biology. Plant》2009,45(1):34-43
Plant regeneration through direct somatic embryogenesis in Aeschynanthus radicans ‘Mona Lisa’ was achieved in this study. Globular somatic embryos were formed directly from cut edges of leaf explants and
cut ends or on the surface of stem explants 4 wk after culture on Murashige and Skoog (MS) medium supplemented with N-phenyl-N′-1, 2, 3-thiadiazol-5-ylurea (TDZ) with α-naphthalene acetic acid (NAA), TDZ with 2,4-dichlorophenoxyacetic acid (2,4-D),
or 6-benzylaminopurine (BA) or kintin (KN) with 2,4-D. MS medium containing 9.08 μM TDZ and 2.68 μM 2,4-D resulted in 71%
of stem explants producing somatic embryos. In contrast, 40% of leaf explants produced somatic embryos when induced in medium
containing 6.81 μM TDZ and 2.68 μM 2,4-D. Somatic embryos matured, and some germinated into small plants on the initial induction
medium. Up to 64% of stem explants cultured on medium supplemented with 9.08 μM TDZ + 2.68 μM 2,4-D, 36% of leaf explants
cultured on medium containing 6.81 μM TDZ and 2.68 μM 2,4-D had somatic embryo germination before or after transferring onto
MS medium containing 8.88 μM BA and 1.07 μM NAA. Shoots elongated better and roots developed well on MS medium without growth
regulators. Approximately 30–50 plantlets were regenerated from each stem or leaf explant. The regenerated plants grew vigorously
after transplanting to a soil-less substrate in a shaded greenhouse with more than a 98% survival rate. Three months after
their establishment in the shaded greenhouse, 500 plants regenerated from stem explants were morphologically evaluated, from
which five types of variants that had large, orbicular, elliptic, small, and lanceolate leaves were identified. Flow cytometry
analysis of the variants along with the parent showed that they all had one identical peak, indicating that the variant lines,
like the parent, were diploid. The mean nuclear DNA contents of the variant lines and their parent ranged from 4.90 to 4.99 pg
2C−1, which were not significantly different statistically. The results suggest that the regenerated plants have a stable ploidy
level, and the regeneration method established in this study can be used for rapid propagation of ploidy-stable Aeschynanthus radicans. 相似文献
10.
Filipendula ulmaria (L.) Maxim (meadowsweet) is a medicinal plant that is claimed to have several biological activities, including anti-tumor,
anti-carcinogenic, anti-oxidant, anti-coagulant, anti-ulcerogenic, anti-microbial, anti-arthritic, and immunomodulatory properties.
This report describes, for the first time, an efficient plant regeneration system for F. ulmaria via adventitious shoot development from leaf, petiole, and root explants cultured on Murashige and Skoog’s minimal organics
medium containing different concentrations of thidiazuron (TDZ), benzyladenine, and kinetin either alone or in combination
with different auxins. Relatively extensive/prolific shoot regeneration was observed in all three explant types with TDZ in
combination with indole-3-acetic acid (IAA). Gibberellic acid (GA3), TDZ, and IAA combinations were also tested. The best shoot proliferation was observed among root explants cultured on media
supplemented with 0.45 μM TDZ + 2.85 μM IAA + 1.44 μM GA3. Regenerated shoots were transferred to rooting media containing different concentrations of either IAA, indole-3-butyric
acid (IBA), naphthalene acetic acid, or 2,4-dichlorophenoxyacetic acid. Most shoots developed roots on medium with 2.46 μM
IBA. Rooted explants were transferred to vermiculite in Magenta containers for a 2-wk acclimatization period and then finally
to plastic pots containing potting soil. The plantlets in soil were kept in growth chambers for 2 wk before transferring to
greenhouse conditions. 相似文献
11.
Xiuping Zou Demou Li Xiaoying Luo Keming Luo Yan Pei 《In vitro cellular & developmental biology. Plant》2008,44(3):169-177
Highly efficient Agrobacterium-mediated transformation of trifoliate orange (Poncirus trifoliata (L.) Raf.) was achieved via indirect shoot organogenesis. Stable transformants were obtained from epicotyl segments infected
with Agrobacterium strain EHA 105 harboring the binary vector pBI121, which contained the neomycin phosphotransferase gene (NPTII) as a selectable
marker and the β-glucuronidase (GUS) gene as a reporter. The effects of regeneration and selection conditions on the transformation
efficiency of P. trifoliata (L.) Raf. have been investigated. A 7-d cocultivation on a medium with 8.86 μM 6-benzylaminopurine (BA)+1.43 μM indole-3-acetic
acid (IAA) was used to improve callus formation from epicotyl segments after transformation. A two-step selection strategy
was developed to select kanamycin-resistant calluses and to improve rooting of transgenic shoots. Transgenic shoots were multiplied
on shoot induction medium with 1.11 μM BA + 5.71 μM IAA. Using the optimized transformation procedure, transformation efficiency
and rooting frequency reached 417% and 96%, respectively. Furthermore, the number of regenerated escape shoots was dramatically
reduced. Stable integration of the transgenes into the genome of transgenic citrus plants was confirmed by GUS histochemical
assay, PCR, and Southern blot analysis. 相似文献
12.
Xianqing Huang Zhanyong Wei Xiaoping Gao Shujing Yang Yanhong Cui 《International journal of peptide research and therapeutics》2008,14(2):89-95
In this paper, the sterilization of surfactin and fengycin to Bacillus cereus was observed, and the optimization of the inactivation of surfactin and fengycin to spores of B. cereus by a response surface methodology was studied. Results showed that surfactin and fengycin had high sterilization to B. cereus, whose minimal inhibitory concentration was 31.25 μM and 62.5 μM respectively. The optimization result indicated that spores
of B. cereus could be inactivated by two orders of magnitude when the temperature was 20.41°C, the action time was 21.13 h, and the concentration
(surfactin/fengycin molar ratio 1:1) was 54.20 μM. 相似文献
13.
B. Vinterhalter J. Savić J. Platiša M. Raspor S. Ninković N. Mitić D. Vinterhalter 《Plant Cell, Tissue and Organ Culture》2008,94(3):299-303
Shoot cultures of nickel hyperaccumulating Alyssum murale were established from epicotyl explants of seedlings aseptically germinated on hormone-free MS medium. They were further
maintained on media with 0–0.92 μM kinetin. Optimal shoot multiplication was at 0.46 μM kinetin. Inoculation by shoot wounding
was performed with overnight suspension of A. rhizogenes A4M70GUS which contains GUS gene cointegrated in pRiA4. After 30 days hairy roots were produced at the wounding site in 31
explant (25% out of 124). Hairy roots were excised and further propagated on hormone-free medium as separate clones. In the
first passage clones 3 and 6 could be distinguished by fast growth and spontaneous shoot regeneration. In other clones (12,
23 and 25) shoot regeneration required presence of cytokinins. The five shoot culture clones regenerated from hairy roots
were further cultured on media with 0.46 μM kinetin. These shoots were characterized by good elongation and lateral shoot
branching, short internodes, minute slightly curled leaves and well developed plagiotropic root system spreading over the
surface of media. Thus all plants regenerated from hairy root cultures manifested the characteristic Ri syndrome phenotype.
They all had a strong positive GUS reaction. PCR analysis confirmed presence of uidA sequence from the gus construct. They were also tolerant to nickel accumulating up to 24,700 μg g−1 dry weight. 相似文献
14.
Xiaohuan Wang Zhenhua Gao Yunzhen Wang Ray A. Bressan Stephen C. Weller Xia Li 《In vitro cellular & developmental biology. Plant》2009,45(4):435-440
An in vitro regeneration system with a 100% efficiency rate was developed in peppermint [Mentha x piperita] using 5- to 7-mm-long second internode stem segments of 3-wk-old stock plants. Shoots developed at sites of excision on
stem fragments either directly from the cells or via primary calluses. The optimal medium for maximum shoot initiation and
regeneration contained Murashige and Skoog (MS) salts, B5 vitamins, thidiazuron (TDZ, 11.35 μM), ZT (4.54 μM), 10% coconut
water (CW), 20 g l−1 sucrose, 0.75% agar, adjusted to pH 5.8. A frequency of 100% shoot initiation was achieved, with an average of 39 shoots
per explant. This regeneration system is highly reproducible. The regenerated plants developed normally and were phenotypically
similar to Black Mitcham parents. 相似文献
15.
Landi Sun Suiwen Hou Dali Wu Yingcong Zhang 《In vitro cellular & developmental biology. Plant》2008,44(5):396-400
This study describes a reliable protocol for callus induction and rapid mass propagation of the ecologically important plant,
Zygophyllum xanthoxylon (Bunge) Maxim. The optimum callus induction medium was Murashige and Skoog (MS) supplemented with 4.4 μM 6-benzylaminopurine
(BAP) and 2.7 μM α-naphthalene–acetic acid (NAA), on which the callus induction frequencies from different seedling explants
were all 100%. However, seedling-derived callus did not form regenerated shoots. In order to achieve shoot multiplication,
shoots were developed from cultured plumules, at an average of 3.1 shoots per explant, and the regenerated shoot tips were
further multiplied by subculture. The best shoot multiplication from shoot tips was achieved on MS supplemented with 5.4 μM
NAA and 22.2 μM BAP after 40 d of culture. Seventy-three percent of regenerated shoots formed roots when cultured on MS supplemented
with 8.6 μM IAA after 4 wk of culture. The plants that acclimatized successfully in sand flourished the following year, with
normal morphology and growth characteristics. 相似文献
16.
Sclerocarya birrea (marula) is an indigenous South African tree with highly valued medicinal and nutritional properties. Induction of nodular
meristemoids from leaf explants was achieved on Murashige and Skoog (MS) and woody plant medium (WPM) supplemented with 6-benzyladenine
(BA) in combination with naphthalene acetic acid (NAA), indole-3-butryric acid (IBA) and indole-3-acetic acid (IAA). Induction
of nodular meristemoids from 86% of the leaf cultures was achieved on MS medium with 4.0 μM BA and 1.0 μM NAA. High levels
(78–100%) of induction were also achieved on WPM with different concentrations of BA (1.0–4.0 μM) and IBA (1.0–4.0 μM). The
highest conversion of meristemoids into shoots was only 22% for 4.0 μM BA and 1.0 μM NAA on MS initiation medium. This was
improved to 62% when nodular clusters were cultured in a MS liquid medium. Histological studies revealed the globular stage
of the nodular meristemoids. This protocol has potential for application in mass micropropagation and plant breeding of S. birrea. 相似文献
17.
Xiuli Shen William S. Castle Frederick G. GmitterJr 《Plant Cell, Tissue and Organ Culture》2009,97(1):103-108
A suitable protocol for micropropagation of Casuarina hybrid, Casuarina equisetifolia L. × Casuarina glauca Sieber ex Spreng (C. e. × C. g.), was developed. When seeds without seed coats were cultured on 4 germination media, the optimal seed germination percentage
(91%) was obtained on 0.8% agar solidified water medium. Shoot multiplication was achieved by culturing 2-cm long epicotyls,
excised from germinated seedlings, on MS (Murashige and Skoog 1962) basal medium supplemented with BA (6-benzylaminopurine)
at 4.4, 8.8, 17.8 and 35.6 μM. The greatest percentage of axillary bud sproutings (87.5%), mean number of sprouts per explant
(3.8), and shoot length (3.2 cm) were achieved on MS medium supplemented with 17.8 μM BA. MS medium supplemented with 4 different
concentrations of IBA (indole-3-butyric acid) (4.3, 8.7, 13.0 and 17.4 μM) were used for rooting of in vitro grown shoots.
The highest rooting percentage (65.6%), mean number of roots per explant (2.5) and mean length of roots per explant (1.6 cm)
was achieved at 13.0 μM IBA. Rooted shoots grew well after transfer to a substrate of peat and pinebark (7:3) in the greenhouse. 相似文献
18.
Isabelle Lefèvre Geoffrey Marchal Enrique Corréal Andréa Zanuzzi Stanley Lutts 《Plant Growth Regulation》2009,59(1):1-11
Seeds, young plants and adult plants of the perennial Mediterranean leguminous shrub Dorycnium pentaphyllum Scop. were exposed to Cd (1–100 μM) or Zn (10–10,000 μM) on nutrient solution. This species is resistant to Cd and Zn at
different phenological stages. The lowest doses of Zn and Cd improved seed germination and young seedling growth, while only
the highest doses of both heavy metals inhibited germination and decreased growth. High doses of Cd reduced seed imbibition
and young seedling water content, while Zn did not. Osmotic adjustment was more efficient in Zn-treated young plants than
in Cd-treated ones, while chlorophyll concentrations decreased in the former but not in the latter. Those differences were
not observed anymore in adult plants. Exclusion processes were more efficient at the adult stage than at the young seedling
stage and were more marked in response to Zn than to Cd. It is concluded that D. pentaphyllum could be used for phytostabilization of heavy metal-contaminated areas. The physiological strategies of tolerance, however,
differ according to the age of the plants and the nature of the metal. 相似文献
19.
The inhibitors of cytokinin N-glucosylation are known to influence the growth of some plant objects including cotyledons. The use of the plate meristem
of zucchini cotyledon as an experimental system allowed us to study for the first time the way in which the changes in the
cell division are integrated in this growth reaction. Roscovitine, a potent inhibitor of cytokinin N-glucosylation and cycline-dependent kinases, did not show to have an effect on the meristem activity when applied in 100 μM
to cultivated zucchini cotyledons, and acted as an inhibitor in concentrations higher than 400 μM. A 200 μM roscovitine stimulated
both palisade cell division and growth. In different seed batches, 400 μM roscovitine acted as a stimulator or an inhibitor.
A much stronger stimulating effect on growth and cell division was observed after application of benzyladenine (BA, 10 μM).
In contrast to BA, roscovitine provoked a formation of principally flat lamina. In combined treatments, it lowered the stimulating
effect of BA; 400 μM roscovitine combined with BA severely suppressed the growth and division activity. This cellular behavior
and changes in cotyledon growth could be due to the roscovitine-provoked changes in endogenous cytokinin levels via the inhibition
of cytokinin N-glucosylation. Roscovitine-caused stimulation of cell growth and division is stronger in the marginal meristem than that
registered in central regions of the cotyledon blade. In this region it also changed the pattern of cell division and lowered
the adhesion between the clusters, which enhanced the appearance of local ruptures of the cotyledon edges. The first palisade
layer of the plate meristem of cultured zucchini cotyledons, the natural mono-layer of proliferating palisade cells, may be
used for screening the inhibitors of cycline-dependent kinases and cytokinin N-glucosylation with regard to their effects on cell division and growth. 相似文献
20.
Jennifer L. Bankers-Fulbright Kathleen R. Bartemes Gail M. Kephart Hirohito Kita Scott M. O’Grady 《The Journal of membrane biology》2009,228(2):99-109
Human eosinophils spontaneously adhere to various substrates in the absence of exogenously added activators. In the present
study a method was developed for characterizing eosinophil adhesion by measuring changes in impedance. Impedance measurements
were performed in HCO3-buffered HybriCare medium maintained in a humidified 5% CO2 incubator at 37°C. Impedance increased by more than 1 kΩ within minutes after eosinophils made contact with the substrate,
reaching a peak within 20 min. Blocking mobilization of intracellular [Ca2+] that precedes adhesion with BAPTA-AM (10 μM) completely inhibited the rise in impedance as well as the changes in cell shape
typically observed in adherent cells. However, lowering the extracellular [Ca2+] with 2.5 mM EGTA did not inhibit the increase in impedance. Pretreatment with anti-CD18 antibody to block substrate interactions
with β2-integrins, or jasplakinolide (2 μM) to block actin reorganization, abolished the increase in impedance and adherent morphology
of the cells. Exposure of eosinophils to the phosphatidylinositol 3 kinase inhibitor LY294002 (5 μM) or treatment with protein
kinase C zeta pseudosubstrate to competitively inhibit activity of the enzyme significantly reduced the increase in impedance
and inhibited the cell spreading associated with adhesion. These results demonstrate a novel method for measuring eosinophil
adhesion and showed that, following formation of a tethered attachment, a rapid increase in intracellular [Ca2+] precedes the cytoskeletal rearrangements required for cell shape changes and plasma membrane-substrate interactions associated
with adhesion. 相似文献