共查询到20条相似文献,搜索用时 15 毫秒
1.
C Cerni 《In vitro》1984,20(4):305-313
The frequency of sister chromatid exchange (SCE) was determined in a nontransformed diploid rat cell line, FR3T3 , under several tissue culture variables such as cultivation temperature, growth conditions of cells, and concentrations of 5-bromo-2'-deoxyuridine (BrdU). The conclusions to be drawn from these experiments are: (a) The cell growth and mechanisms(s) of SCE formation in FR3T3 cells are largely temperature independent (or efficiently regulated) in the range between 33 and 40.5 degrees C. (b) The concentration limits for BrdU incorporation are 5 to 100 microM; baseline frequency is about 11 SCE/metaphase (constant up to 20 microM BrdU) and increases only moderately at higher BrdU concentrations. (c) Toxic levels of BrdU (150 microM) cause a decrease of SCE rates below that found at 100 microM, presumably due to selective cell death. (d) Keeping cells growth arrested over a long period causes substantial SCE induction after replating. (e) Induced increase of SCEs probably occurs in this manner during the first cell cycle after release from growth arrest. It is no longer detectable after the fourth consecutive cell division. 相似文献
2.
Summary Methyl jasmonate (MeJA) interacted significantly with both indole-3-acetic acid (IAA) and 6-benzylaminopurine (BA) to influence
cell growth of cultured Onosma paniculatum cells. Cell growth decreased with increasing concentrations of MeJA from 0.004–4.45 μM with or without IAA and BA. The same concentrations of MeJA (0–4.45 μM) increased the cell growth with IAA and BA, when administered to the cultured cells in M9 medium. This was found to enhance the production of shikonin. The optimum time for MeJA addition for enhanced shikonin formation
was 4 d after cell inoculation in M9 medium. Furthermore, shikonin formation was affected significantly by both MeJA/IAA and MeJA/BA combinations. Shikonin content
was enhanced by increasing MeJA concentrations with IAA concentrations in the range of 0–28 μM and with BA concentrations in the range of 0–44.38 μM in MeJA/BA experiments, respectively. The optimal combination of MeJA and IAA was 4.45 μM and 0.28 μM, while MeJA and BA concentrations of 4.45 μM and 2.22 μM were optimal for shikonin formation. The result also showed that MeJA increased phenylalanine ammonia-lyase (PAL) and p-hydroxybenzoic acid-geranyltransferase (PHB-geranyltransferase) activites during the course of shikonin formation, but decreased
the activity of PHB-O-glucosyltransferase within 9 d after inoculation. These results suggest that enhanced shikonin formation in cultured Onosma paniculatum cells induced by MeJA involves regulation of the key enzyme activities. 相似文献
3.
Summary The growth rate of spontaneously transformed BALB/3T3 cells is proportional to glutamine concentration between 50 and 400
μM, with little or no growth occurring in less than 50 μM glutamine. By contrast, nontransformed BALB/3T3 cells multiply, although slowly, with as little as 20 μM glutamine. Neither cell type depletes the medium of glutamine at the low concentrations. Cystine requirements of both cell
types increase with serum concentration, probably due to the binding of half-cystine residues by the serum. Calf serum is
a much more potent stimulator of cell multiplication than calf lymph, especially for the nontransformed cells. The rate of
cell multiplication can be reduced by lowering the concentration of essential amino acids to the physiologic level found in
body fluids, but the growth limitations can be fully compensated by simply raising the serum concentration. Growth factors
may act by enhancing the utilization of amino acids, particularly of glutamine which is a required substrate for the first
and chief regulatory steps of purine and pyrimidine synthesis. Lymph, which is coextensive with interstitial fluid in vivo,
is poor in growth factors for the nontransformed BLAB/3T3 cells as well as for recently explanted mouse embryo cells, which
raises questions of how normal cell growth is maintained in the body.
This work was supported by USPHS grant CA-15744 from the Division of Extramural Activities, National Cancer Institute; by
American Cancer Society Research Development Program grant RD-231; and by The Council for Tobacco Research grant 1948. 相似文献
4.
Efficient plant regeneration from cell suspension-derived callus of East Indian rosewood (Dalbergia latifolia Roxb.) 总被引:2,自引:0,他引:2
A procedure is outlined for the establishment of a proliferating cell suspension culture of East Indian rosewood (Dalbergia latifolia Roxb.) and efficient plant regeneration from callus derived from such cultures. Callus was induced from hypocotyl segments
derived from 1-week-old axenic seedlings on Murashige and Skoog (1962) medium (MS) containing 10.8 μM naphthaleneacetic acid (NAA) and 2.2 μM benzyladenine (BA). Calli were increased by subculturing on MS supplemented with same growth regulators and 10% coconut water
(CW). Friable calli were used to initiate cell suspension cultures. Optimum cell proliferation occurred in MS containing 10.8
μM NAA, 2.2 μM BA and 10% CW, using an initial inoculum cell density of 2%. Cell clumps composed of 20–25 cells harvested from suspension
cultures at the exponential growth phase readily formed callus within 3 weeks following plating on the semi-solid MS as above.
High-frequency shoot-bud differentiation was induced in these calli on MS containing 2.7 μM NAA and 13.3 μM BA. The regeneration frequency declined at higher BA concentrations. The organogenic potential of the cell suspensions was
influenced by the age of the culture. Regenerated shoots were rooted on half-strength MS containing 5.7 μM indole-3-acetic acid, 4.9 μM indole-3-butyric acid and 5.3 μM indole-3-propionic acid. The plantlets were acclimatized and established in soil.
Received: 22 August 1997 / Revision received: 21 May 1998 / Accepted: 1 June 1998 相似文献
5.
Terry L. Riss Kenneth P. Karey B. Daniel Burleigh David Farker David A. Sirbasku 《In vitro cellular & developmental biology. Plant》1988,24(11):1099-1106
Summary A serum-free clonal density growth assay was developed for the quantification of the biological activity of human recombinant
insulin-like growth factor I (IGF-I). The assay measures IGF-I stimulated growth of Balb/c 3T3 cells cultured over 4 d on
poly-d-lysine-coated plastic surfaces in a serum-free medium formulation composed of a 1∶1 (vol/vol) mixture of Ham's F12 and Dulbecco's
modified Eagle's media, supplemented with 3.0 ng/ml bovine basic fibroblast growth factor (bFGF), 10 μg/ml human transferrin,
100 μg/ml ovalbumin, and 1.0 μM dexamethanose. Low-temperature trypsinization of serum-supplemented stock cultures combined with the use of poly-d-lysine-coated plates made it unnecessary to use serum or fibronectin to promote cell attachment and survival. Serum-free
growth conditions were optimized with respect to the concentrations of the supplements. Addition of IGF-I resulted in 3.5-fold
more cells than control cultures without IGF-I after 4 d. Deletion of bFGF resulted in no IGF-I stimulation of growth. The
concentrations of various preparations of IGF-I required to achieve one-half maximal stimulation of cell number (ED50), ranged between 1.25 and 4.7 ng/ml. In parallel assays, IGF-I was 6.6 times more potent than human recombinant insulin-like
growth factor II and 32 times more potent than insulin. When cells were seeded into medium containing IGF-I, transferrin,
ovalbumin, and dexamethasone but no bFGF, growth was minimal. Dose-response addition of bFGF showed an ED50, of 0.9 ng/ml. The methods reported are useful to monitor the biological potency of recombinant and natural-source growth
factors as well as providing a new means of studying the multiple growth factor requirements of Balb/c 3T3 cells in cultures.
This work was supported by a contract from IMCERA Bioproducts, Inc. 相似文献
6.
Vegetable soybeam germplasm was screened for its tolerance to 0, 50 and 100 μM Al in solution culture. Plants were inoculated with prescreened acid-Al tolerantBradyrhizobium japonicum strain USDA 110 and a localRhizobium isolate SM867. Aluminum concentrations of 0, 50, and 100 μM affected the root lengths of all germplasm lines in the first few weeks of their growth. At 100 μM, the plants had severely stunted roots throughout the growing period of 35 days, but at 50 μM the initial stunting of the roots was overcome after the third week of growth, and there were no significant differences
between the root lengths of these plants and of the controls. The appearance of the first nodule was delayed for 2–3 and 4–5
days at 50 μM and 100 μM Al, respectively. There was a significant reduction in nodule numbers and acetylene reduction activity (ARA) at 100 μM Al. At 50 μM Al, even though the number of nodules was decreased significantly, nodules were larger in size, so there was no significant
reduction in nodule fresh weight and ARA. No significant differences in nitrogen fixing abilities of the soybean lines were
observed between the twoRhizobium strains. Germplasm line Kahala showed the greatest tolerance to 50 μM Al, and Kahala, Kim and Wolverine tolerated 100 μM Al better than other germplasm lines. 相似文献
7.
A. Tirajoh T. S. Kyung Z. K. Punja 《In vitro cellular & developmental biology. Plant》1998,34(3):203-211
Summary Somatic embryogenesis in American ginseng (Panax quinquefolium L.) was investigated from three explant sources (root, leaf and epicotyl) with Murashige and Skoog (MS) medium containing
different growth regulators. Mature roots and leaves obtained from 3- to 5-yr-old field-grown plants, and seedling leaves
and epicotyls from plantlets grownin vitro, were evaluated. From root and epicotyl explants, callus development was optimal with 3,6-dichloro-o-anisic acid (dicamba)
(9.0 μM) and kinetin (KN) (5.0 μM) as the growth regulators. When these calluses were transferred after 3 mo. to dicamba alone (9.0 μM), somatic embryo formation was observed at an average frequency of 15.6% in root explants after an additional 3 mo., and
2% in epicotyl explants after an additional 6 mo. No plantlets were recovered because the embryos germinated to form shoots
with no roots. From leaf explants, callus growth was optimal with α-naphthaleneacetic acid (NAA) at 10.0 μM and 2,4-dichlorophenoxyacetic acid (2,4-D) at 9.0 μM. Somatic embryos developed on this medium, with the highest frequency (40%) obtained after 3 mo. from seedling-leaf explants.
Calluses on mature leaves formed somatic embryos after 7 mo. with NAA/2,4-D at an average frequency of 30%. Transfer of these
somatic embryos to 6-benzyladenine/gibberellic acid (4.4/2.9 μM) promoted shoot development but no roots were observed. Up to 100% of germination was observed within 6 wk on half-strength
MS salts containing activated charcoal (1%) and on NAA/2,4-D (5.0/4.5 μM) with charcoal (1%). On the latter medium, somatic embryos enlarged and frequently gave rise to new somatic embryos after
a brief callusing phase. The embryos germinated through a two-stage process, involving the elongation of the root followed
by the formation of a shoot. The highest recovery of ginseng plantlets from germinated embryos was 61.0%. Following transfer
to potting medium and maintenance under conditions of high humidity and low light intensity, the plantlets elongated and developed
new leaves. A high percentage (50%) of these plants have been acclimatized to soil. 相似文献
8.
Masami Ogasawara David A. Sirbasku 《In vitro cellular & developmental biology. Plant》1988,24(9):911-920
Summary Growth of the MCF-7, T47D, and ZR-75-1 human breast cancer cells was established in a serum-free defined medium (MOM-1) composed
of a 1∶1 (vol/vol) mixture of Ham's F12 medium and Dulbecco's modified Eagle's medium containing 15 mM HEPES (pH 7.2), 2 mM 1-glutamine, 20 μg/ml glutathione, 10 μg/ml insulin, 10 μg/ml transferrin (Tf), 10 ng/ml selenous acid, 0.3 nM triiodothyronine, 50 μg/ml ethanolamine, 20 ng/ml epidermal, growth factor, 2.0 nM 17β-estradiol, and 1.0 mg/ml bovine serum albumin (BSA). Proliferation in MOM-1 was 50 to 70% of the serum stimulated rate.
Deletion of components from MOM-1 gave a medium (Tf-BSA) containing only HEPES, 10 μg/ml Tf, and 200 μg/ml BSA, which sustained
MCF-7 and T47D cells in a slowly dividing and mitogen responsive state; ZR-75-1 cells required Tf plus 1.0 mg/ml BSA. In Tf-BSA,
insulin and insulin-like growth factor I(IGF-I) were mitogenic with ED50 values of 2 to 3 ng/ml and 30 to 150 pg/ml, respectively, with MCF-7 cells. The T47D cells were responsive to these factors
in Tf-BSA but required 10-fold higher concentrations for ED50. At saturating concentrations, insulin and IGF-I promoted 1.5 to 3.5 cell population doublings over controls in 8 d. At≤ng/ml
concentrations, epidermal growth factor, insulin-like growth factor II, and basic fibroblast growth factor were mitogenic
for human breast cancer cells in Tf-BSA. Mitogen activities in uterus and pituitary extracts were assayed readily in Tf-BSA.
This new method offers a convenient means of comparing the potencies of growth-promoting factors on human breast cancer cells
without interfering activities known to be present in serum.
This work was supported by grants CA-38024 and CA-26617, from the National Cancer Institute, Bethesda, MD, and by American
Cancer Society grant BC-255 and grant 2225 from the Council for Tobacco Research, USA, Inc. 相似文献
9.
Terry L. Riss' David A. Sirbasku 《In vitro cellular & developmental biology. Plant》1989,25(2):136-142
Summary The effect of 17β-estradiol (E2) on growth of GH4C1 rat pituitary tumor cells was investigated under serum-free conditions and with medium containing charcoal-extracted serum.
Serum-free TRM-1 medium was a 1∶1 (vol/vol) mixture of F12-DME supplemented with 50 μg/ml gentamicin, 15 mM 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid, 10 μg/ml insulin, 10 μg/ml transferrin, 10 ng/ml selenous acid, 10 nM 3,5,3′-triiodothyronine (T3), 50 μM ethanolamine, and 500 μg/ml bovine serum albumin. The cells grew continuously in TRM-1 but were E2 responsive only when growth was retarded by reducing the T3 concentration to 10 pM (TRM-MOD). Addition of 1 to 10 nM E2 to TRM-MOD increased growth by 0.3 to 0.9 cell population doublings over controls in 9 d. By using medium supplemented with
charcoal-extracted sera, basal growth became 1 to 1.5 cell population doublings in 9 d. Addition of 0.1 pM E2 to medium containing charcoal-extracted serum caused a significant increase in cell number whereas pM-nM concentrations stimulated 200 to 570% increases over controls. The effect of steroid hormone was the same in phenol-red-containing
and indicator-free medium. The data presented confirm that the major requirements for demonstration of estrogenic effects
in culture were optimum concentrations of thyroid hormones and the presence of yet-to-be-characterized serum factors.
This work was supported by National Cancer Institute (Bethesda, MD) grants CA-26617 and CA-38024, American Cancer Society
grant BC-255, and grant 2225 from The Council for Tobacco Research, U.S.A., Inc. 相似文献
10.
The effect of 2,4-dichlorophenoxyacetic acid (2,4-D) at low concentrations on cell cycle duration and sister-chromatid exchange
(SCE) frequency was studied using meristem root-tip cells ofAllium sativum L. 2,4-D induced a marked prolongation of the cell cycle. At the same time, small but statistically significant increases
in SCE frequencies were observed at 5 μM and 15 μM 2,4-D concentrations. The significance of these findings in the evaluation
of mutagenic activity of 2,4-D is discussed. 相似文献
11.
The effects of low concentrations of aluminium on the growth and uptake of nitrate-N by white clover 总被引:1,自引:0,他引:1
Summary The effects of aluminium (Al3+) at concentrations of 0, 25, 50 and 100 μM on the growth of white clover, dependent upon N supplied as NO
3
−
, were examined in flowing solution culture. Plants were established with a normal nutrient supply for 7 weeks and then grown
with carefully controlled pH (at 4.5) and P concentrations, and with 0, 25, 50 or 100 μM Al3+ for a further three weeks. There were rapid visual effects (i.e. symptoms of P deficiency and reduction in root extension) and the dry weights of shoots and roots were reduced at 50 and
100 μM. Less than 10% of Al absorbed from solution was transported to the shoots. The uptake of P, and its transport between roots
and shoots, were reduced in plants grown with Al. The uptake of NO
3
−
stopped immediately after the introduction of 50 or 100 μM Al, and was significantly reduced at 25 μM after three weeks.
During a second phase of the experiment, plants previously grown at 0, 25, 50 and 100 μM Al, were grown for a further 2 weeks either with NO
3
−
(with and without 50 μM Al3+) or without NO
3
−
but with inoculation by Rhizobia (and with or without 50 μM Al3+). The effects of the previous treatments with Al on N uptake were small during the second phase, but uptake by all plants
was restricted when Al was present. Inoculation did not result in nodulation in the second phase when Al3+ was present in the solution, but Al already in the plant from the first phase did not prevent nodulation in the absence of
Al during the second phase. 相似文献
12.
J. N. Wu E. Tiffany-Castiglioni 《In vitro cellular & developmental biology. Plant》1987,23(11):765-774
Summary Time- and dose-dependent toxic effects of lead (Pb) acetate on astroglia, oligodendroglia, and meningeal fibroblasts cultured
from immature rat brain were measured. Cultures were exposed for 3 d to Pb (1,10, and 100 μM) and then examined immediately (Day 0) or 3 or 10 d after Pb treatment was discontinued. The percentages of astroglia and
fibroblasts excluding dye were unaffected by Pb, whereas the percentage of oligodendroglia excluding dye decrease significantly
(P<0.01) at all time points after exposure to 100 μM Pb. Lead (100 μM) also reduced the total cell numbers of astroglia, oligodendroglia, and meningeal fibroblasts. Amino acid incorporation into
protein by oligodendroglia was stimulated after exposure to 100 μM Pb at all time points and also by 1 and 10 μM on Day 3. Incorporation was stimulated in astroglia only on Day 0 by 10 and 100 μM. Hydrocortisone-stimulated glycerolphosphate dehydrogenase (GPDH) activity was assayed in oligodendroglia cultures. A significant
decrease in specific activity was seen after a 4-d exposure to lead. Because oligodendroglia are responsible for myelin synthesis
in the central nervous system, and GPDH may synthesize a precursor for myelin lipid synthesis, it was proposed that the hypomyelination
observed in lead-intoxicated neonatal rats may result partially from a primary toxic effect on oligodendroglia. GPDH activity
was not inhibited by Pb in mixed glial cultures containing both astroglia and oligodendroglia. This result suggests that astroglia
in culture have the ability to delay the lead-induced inhibition of oligodendroglial GPDH activity and supports the hypothesis
that astroglia in culture serve a protective function.
This work was supported by Environmental Protection Agency Grant R811500 and by U. S. Department of Agriculture Project M-6839
Animal Health Formula Funding Project 6652. This work was carried out by J.-N. Wu in partial fulfillment of the requirements
for a Master of Science degree in Veterinary Public Health at Texas A&M University. 相似文献
13.
U. Carpentieri J. Myers C. W. Daeschner M. E. Haggard 《Biological trace element research》1988,16(2):165-176
The effects of simultaneous changes of calcium, magnesium, iron, copper, and zinc concentrations were evaluated in normal
human T and B lymphocytes, cultured in cation-depleted media. Optimal concentrations for thymidine incorporation (TI) in both
cell populations were Fe and Zn 15 μM and Cu 5 μM; for t cells Ca 2 mM and Mg 4 mM; for B cells Ca 4 mM and Mg 6 mM. TI decreased with increasing molarity of cations and the decrease was particularly apparent with Cu. Minimal amounts of
Ca and Mg (0.5 mM) were necessary for growth, even in presence of optimal concentrations of Fe, Cu, and Zn. Fe and Cu showed synergistic stimulatory
effects at low concentrations and synergistic inhibitory effects at high concentrations. Antagonism between Fe and Zn, Cu
and Zn, and Ca and Zn was also demonstrated. CD4/CD8 increased with PHA stimulation in presence of Zn, and decreased with
ConA stimulation in presence of Zn or Fe. The results demonstrate: (1) the relationship and interdependence of Fe, Cu, and
Zn concentrations in modulating the growth of normal lymphocytes; (2) the stimulatory effects of Fe on B cells and Zn on CD8
positive cells; (3) the inhibitory effect of Cu at concentrations lower than those of Fe and Zn; (4) the requirement of Ca
and Mg in certain concentration and ratio for the action of the other cations; and (5) the Ca and Mg requirement for the growth
of B cells higher than T cells. 相似文献
14.
Summary Chili pepper (Capsicum annuum L., cv. Tampique?o 74) cell suspensions were employed to study the influence of phenylalanine and phenylpropanoids on the
total production of capsaicinoids, the hot taste compounds of chili pepper fruits. The effect of capsaicinoid precursors and
intermediates on the accumulation of lignin as an indicator of metabolic diversion was also investigated. Addition of 100
μM of either phenylalanine, cinnamic or caffeic acids to chili pepper cell cultures did not cause significant increases in total
capsaicinoids (expressed as capsaicin content, and calculated as averages of the measured values) during the growth cycle.
The highest total capsaicinoid content was recorded in cultures grown in the presence of vanillin (142.61 μg g−1 f.wt.), followed by cells treated with 100 μM vanillylamine (104.88 μg g−1 f.wt.), p-coumaric acid (72.36 μg g−1 f.wt.). and ferulic acid (34.67 μg g−1 f.wt.). Capsaicinoid content for control cells was 13.97 μg g−1 f.wt. Chili pepper cell suspensions cultured in the presence of 100 μM of either phenylalanine, or cinnamic, caffeic, or ferulic acids, or the same concentration, of vanillin and vanillylamine,
did not exhibit statistically significant differences in the content of lignin as compared with control cells. However, addition
of p-coumaric acid (100 μM) to the cultute medium significantly increased thelignin production (c. 10–15 times the contents of control cells). 相似文献
15.
Kenneth P. Karey Terry L. Riss B. Daniel Burleigh David Parker David A. Sirbasku 《In vitro cellular & developmental biology. Plant》1988,24(11):1107-1113
Summary The binding of human recombinant insulin-like growth factor I (IGF-I) to BALB/c 3T3 mouse embryo fibroblasts has been characterized,
resulting in the development of a radioreceptor assay. Binding of radioiodinated IGF-I (125I-IGF-I) to washed monolayers of BALB/c 3T3 cells was specific, time dependent, and stable, being maximal after a 10-h incubation
at 15°C with no loss of bound ligand or cells through 25 h. Scatchard analysis identified a class of high affinity binding
sites with K
d
=59.6 pM and an estimated 1.57×105 receptors/cell. Half-maximal displacement of bound125I-IGF-I occurred with 15 to 20 ng/ml unlabeled IGF-I competitor. Insulin-like growth factor II and insulin were far less effective
competitors, providing halfmaximal displacement at concentrations of 130 to 170 ng/ml and 2 to 3 μg/ml, respectively. Epidermal
growth factor, transforming growth factor type α, and acidic and basic fibroblast growth factors did not compete for125I-IGF-I binding at 1 μg/ml. Cells fixed with glutaraldehyde before ligand binding did remain attached to culture dishes more
tightly; however such pretreatment destroyed approximately 70% of ligand binding. Crosslinking data indicated that125I-IGF-I binds specifically to a 330-kDalton receptor as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis
under nonreducing conditions. This receptor dissociated into 130-kDalton subunits when analyzed in the presence of dithiothreitol.
This work was supported by a contract from IMCERA Bioproducts, Inc. 相似文献
16.
Duong Tan Nhut Bui Van Le K. Tran Thanh Van 《In vitro cellular & developmental biology. Plant》2001,37(1):44-49
Summary Excised tissues from transverse young stem sections of Lilium longiflorum were cultured on Murashige and Skoog medium supplemented with growth regulators at various concentrations. After 45 d in
culture, the presence of α-naphthaleneacetic acid (NAA) in the culture medium at 5.4 μM resulted in bulblet formation while 2,4-dichlorophenoxyacetic acid (2,4-D) at 2.2 μM resulted in root formation. The presence of IBA (indole-3-butyric acid) in the culture medium at 1.0 μM resulted in shoot formation while plantlet formation occurred when IBA was added at a concentration of 2.0 μM. When 1-phenyl-3-(1,2,3-thiadiazol-5-yl)-urea (TDZ) was added to the culture medium at 1.1 μM, protocorm-like bodies (PLBs) formed, while 2.2 μM resulted in shoot formation (on abaxial and adaxial surfaces). The presence of NAA and TDZ in the culture medium at 5.4 μM and 0.4, 1.1 or 2.2 μM, respectively, resulted in somatic embryo formation while NAA- and 6-benzylaminopurine-(BA) containing culture medium formed
callus or bulblets. The establishment of different regeneration systems when explants are exposed to various growth regulators
demonstrates that the choice of growth regulator combinations and concentrations are of significance in determining the morphogenetic
response and plant regeneration capacity. 相似文献
17.
Summary A somatic embryogenesis protocol was developed for Eschscholzia californica Chan. (California poppy) using embryogenic cell suspensions and optimized media conditions. Rapidly-growing, finely-dispersed
embryogenic cell suspension cultures were established from embryogenic callus and maintained in B5 liquid media supplemented
with 0.5 mg 1−1 (2.26 μM) 2,4-dichlorophenoxyacetic acid. Culture conditions were optimized by investigating the effect of basal media composition,
gyratory shaker speed, various carbon sources, different cytokinins, and AgNO3 on the efficiency of somatic embryogenesis. After 40 d in culture, the somatic embryos that formed were counted and their
overall growth expressed as pecked cell volume. The selected media consisted of either Gamborg (B5) or Murashige and Skoog
(MS) salts and vitamins supplemented with 40 g 1−1 (117 mM) sucrose, 0.05 mg 1−1 (0.22 μM) 6-benzylaminopurine, and 10 mg l−1 (58.8 μM) AgNO3. Somatic embryo production was substantially reduced at shaker speeds above 40 rpm. Glucose and snerose were the most effective
carbon sources, whereas fructose, galactose, and maltose resulted in a reduced yield and growth of somatic embryos. The development
of somatic embryos was promoted by AgNO3 at concentrations below 10 mg l−1 (58.8 μM). A semi-solid medium containing 1.5 g l−1 Gel-rite produced the highest frequency of somatic embryo conversion, and promoted the efficient growth of plantlets. Using
the reported protocol, over 500 viable somatic embryos were produced per 25 ml of embryogenic cell suspension culture. 相似文献
18.
In vivo sister chromatid exchange (SCE) in mouse cells derived from various organs was studied by infusing BrdU from the tail vein. It was found that at BrdU concentrations ranging from 2.2–13.5 g/g/h, the SCE frequency in bone marrow cells seemed to stay at a constant level (1.5–2/cell/two cell cycles) whereas it started to rise as the BrdU dose exceeded this dose range. When BrdU within this dose range was infused continuously from the tail vein for appropriate hours to label chromosomes in various organs, the average SCE frequencies per cell were found to be 1.64 in bone marrow cells, 1.82 in spermatogonia, 1.99 in splenic cells, 2.89 in intestinal cells and 3.69 in cells from adjuvant stimulated lymph nodes. It is suggested that the spontaneous level of the in vivo SCE frequency might be about 1.5–2/cell/two cell cycles in the mouse. In cells derived from intestine and adjuvant stimulated lymph node, some unknown factors might work as a inducer of SCEs resulting in a significant increase in the SCE frequency in these organs. 相似文献
19.
Summary Callus cultures were established from pith tissue of Coryphantha elephantidens (Lem.) Lem. on Murashige and Skoog (MS) basal medium supplemented with 9.05 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 2.3 μM kinetin. Highest shoot regeneration frequency was observed on a medium containing 6.9 μM kinetin and 2.3 μM 2,4-D under 30 μE m−2 s−1 light intensity with a 16-h photoperiod. Calluses retained organogenic potential throughout several passages of subculture
(18 mo.). Shoots were rooted on MS medium without plant growth regulators. All (100%) plantlets transplanted to soil survived
acclimatization. Regenerated plants showed good overall growth and were morphologically similar to the mother plants. 相似文献
20.
Chi D. Ha Peggy G. Lemaux Myeong-Je Cho 《In vitro cellular & developmental biology. Plant》2001,37(1):6-11
Summary An efficient method to produce highly regenerative tissues from seeds of a previously recalcitrant cultivar of Kentucky bluegrass
(Poa pratensis L. ev. Kenblue) was established under dim-light conditions (10–30 μE m−2s−1, 16-h light) using media supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D; 4.5 or 9.0 μM), 6-benzylaminopurine (BA; 0.44 or 2.2 μM), and a high level of cupric sulfate (5.0 μM). The tissues were co-transformed with three plasmids containing the genes for hygromycin phosphotransferase (hpt), β-glucuronidase (uidA; gus), and a synthetic green fluorescent protein gene [sgfp(S65T)]. From 463 individual explants bombarded, 10 independent transgenic events (2.2%) were obtained after a 3–4-month selection
period for hygromycin resistance using 30–100 mg l−1 hygromycin B; of the 10 independent events, seven (70%) were regenerable. Stable integration of the transgene(s) in transgenic
plants was confirmed by polymerase chain reaction and DNA blot hybridization analyses. Coexpression frequency of all three
genes was 20%; for two transgenes, either hpt/uidA or hpt/sgfp(S65T), coexpression frequency was 30–40%. 相似文献