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1.
Gerald Audesirk David Shugarts Gina Nelson Julie Przekwas 《In vitro cellular & developmental biology. Plant》1989,25(12):1121-1128
Summary Neurons from brains of chick embryos and pond snails (Lymnaea stagnalis) were cultured for 3 to 4 d in the presence of no toxins, inorganic lead (PbCl2), or organic lead (trielthyl lead chloride). In chick neurons, inorganic lead reduced the percentage of cells that grew neurites
(IC50=270μM total lead, approximately 70 nM free Pb2+) but did not reduce the number of neurites per cell or the mean neurite length. Triethyl lead reduced the percentage of cells
that grew neuites (IC50=0.24 μM) and the mean neurite length (extrapolated IC50=3.6 μM) but did not reduce the number of neurites per cell. InLymnaea neurons, inorganic lead reduced the percentage of cells that grew neurites (IC50=13 μM total lead; approximately 10 nM free Pb2+). Triethyl lead reduced the percentage of cells that grew neurites (IC50=0.4 μM) and exerted significant toxicity at 0.2 μM. The two forms of lead affected neurite growth in qualitatively different ways, which suggests that their mechansms of action
are different.
These experiments were supported by grants from the Environmental Protection Agency, Washington, DC, and the National Institutes
of Environmental Health Science, Research Triangle Park, NC. 相似文献
2.
The Fusarium metabolite enniatin B is now recognized as a frequent contaminant of grains used for human foods and animal feeds. Yet, so
far very limited data are available on its toxicity and that of other emerging Fusarium mycotoxins (Jestoi M, 2008, Crit Rev Food Sci Nutr 48:21-49). Thus, the mutagenic/genotoxic potential of enniatin B was investigated
in a battery of short-term tests, and its cytotoxicity compared with that of several other mycotoxins. No mutagenicity was
detected in the Ames assay with four Salmonella typhimurium strains, and in the HPRT (hypoxanthine guanine phosphoribosyl transferase) assay with V79 cells, in either the presence or
absence of an external metabolizing enzyme system (rat liver S9). For other types of genotoxicity, i.e., clastogenicity and
chromosomal damage, studied in V79 cells by means of alkaline single-cell gel electrophoresis (Comet) assay and micronucleus
assay, no significant genotoxic potential of enniatin B was revealed. However, the Fusarium metabolite exerts pronounced time- and concentration-dependent cytotoxic effects in V79 cells as determined by Alamar Blue
reduction and by neutral red uptake assays. For instance, IC20 and IC50 values determined for enniatin B by neutral red assay for 48-h exposure are 1.5 μM and 4 μM. These values are higher than
those of the more potent Fusarium toxin deoxynivalenol (IC20 0.7 μM, IC50 of 0.8 μM), but clearly lower than the IC values of several other mycotoxins tested in parallel. Their ranking of cytotoxicity
in V79 cells was as follows: deoxynivalenol > enniatin B > patulin > ochratoxin A > zearalenone > citrinin. Moreover, enniatin
B was found to induce nuclear fragmentation, a sign of apoptosis, already at low submicromolar concentrations. In summary,
despite an apparent lack of mutagenic and genotoxic activity, enniatin B can cause pronounced cytotoxicity in mammalian cells,
detectable at low micromolar concentrations. 相似文献
3.
Łubgan D Jóźwiak Z Grabenbauer GG Distel LV 《Cellular & molecular biology letters》2009,14(1):113-127
Neoplastic cells frequently have an increased number of transferrin receptors. Coupling transferrin to an anti-neoplastic
drug has the potential to overcome multidrug resistance (MDR). The purpose of this study was to examine the distribution and
action of doxorubicin-transferrin conjugate (DOXTRF) in a leukaemia cell line (HL60), a multidrug-resistant leukaemia cell
line (HL60ADR) and a normal tissue cell line (human fibroblasts). The intracellular accumulation of DOX and DOX-TRF was monitored
by direct fluorescence. More DOX-TRF than free DOX was delivered to the tumour cells, and consecutively the levels of DNA
double-strand breaks and apoptosis increased even in the multidrug-resistant cell line. In the normal tissue cell line, DOX-TRF
did not accumulate, and therefore, the levels of DNA double-strand breaks and apoptosis did not increase. Cell viability was
determined using the MTT assay. The IC50 for DOX-TRF was lower than the IC50 value for the free drug in both leukaemia cell lines. The IC50 values for the HL60 cells were 0.08 μM for DOX and 0.02 μM for DOX-TRF. The IC50 values for HL60ADR cells were 7 μM for DOX and 0.035 μM for DOX-TRF. In conclusion, DOX-TRF was able to overcome MDR in the
leukaemia cell lines while having only a very limited effect on normal tissue cells. 相似文献
4.
The Fusarium toxin deoxynivalenol (DON) often co-occurs along with the acetylated derivatives 3-acetyl-DON and 15-acetyl-DON in diets
for ruminants. De-epoxy-DON is formed by rumen micro-organisms, while the acetylated DON derivatives might also undergo ruminal
metabolism with de-epoxy-DON as an end product. However, despite the fact that de-epoxy-DON is the predominant substance finally
absorbed, a complete degradation of the mother compounds can not be assumed for all feeding and metabolic situations of the
cow, and thus raising the question of their possible post-absorptive effects. Hence, the aim of the study was to examine the
effects of all four compounds on the concanavalin A stimulated proliferation of bovine peripheral blood mononuclear cells
(PBMC) using MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) as indicator in vitro and ex vivo. Among
the DON-related compounds, DON and 15-acetyl-DON resulted in a similar IC50 (i.e. the concentration where the proliferation was inhibited by 50%) of 0.5 μM, whereas 3-acetyl-DON was less toxic (IC50 = 2.6 μM), while actually no IC50 could be estimated for de-epoxy-DON which was characterized by a maximum inhibition of approximately 24% at the highest tested
in vitro concentration of 18.29 μM. For the in vivo experiment, 14 Holstein cows were used and fed either an uncontaminated control diet (CON) or a diet contaminated
with Fusarium toxins, with DON being the predominating toxin for 18 weeks when blood was collected for PBMC isolation and subsequent proliferation/viability
assay. The complete diets for the CON and FUS group contained 0.4 and 4.6 mg DON/kg DM, respectively, at that time. Exposure
of dairy cows to the FUS diet resulted in maximum serum de-epoxy-DON levels of 52 ng/ml (0.19 μM), while levels of the unmetabolized DON reached maximum levels of 9 ng/ml (0.03 μM). The PBMC of these cows were slightly less viable, by approximately 18% (p = 0.057), while stimulation capability was not decreased at the same time. Although de-epoxy-DON was characterized by the
lowest in vitro toxicity among the tested DON-related compounds, there appeared to be a lower viability of the PBMC isolated
from cows fed the FUS diet, which had nearly exclusively de-epoxy DON in serum beside slight traces of unmetabolized DON.
Thus, the factors responsible for these apparent discrepancies need to be clarified. 相似文献
5.
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
6.
M. J. Perry J. O’Connell C. Walker T. Crabbe D. Baldock A. Russell S. Lumb Z. Huang D. Howat R. Allen M. Merriman J. Walls T. Daniel B. Hughes F. Laliberte G. A. Higgs R. J. Owens 《Cell biochemistry and biophysics》1998,29(1-2):113-132
We present the in vitro characterization of a novel phosphodiesterase type 4 inhibitor, CDP840 (R-[+]-4-[2-{3-cyclopentyloxy-4-methoxyphenyl}-2-phenylethyl]pyridine), which has shown efficacy in a phase II allergen challenge
study in asthmatics without adverse effects. CDP840 potently inhibits PDE-4 isoenzymes (IC50 2–30 nM) without any effect on PDE-1, 2, 3, 5, and 7 (IC50>100 μM). It exhibited no significant selectivity in inhibiting human recombinant isoenzymes PDE-4A, B, C or D and was equally active
against the isoenzymes lacking UCR1 (PDE-4B2 and PDE-4D2). In contrast to rolipram, CDP840 acted as a simple competitive inhibitor
of all PDE-4 isoenzymes. Studies with rolipram indicated a heterogeneity within all the preparations of PDE-4 isoenzymes,
indicative of rolipram inhibiting the catalytic activity of PDE-4 with both a low or high affinity. These observations were
confirmed by the use of a PDE-4A variant, PDE-4A330–886, which rolipram inhibited with low affinity (IC50=1022 nM). CDP840 in contrast inhibited this PDE-4A variant with similar potency (IC50=3.9 nM), which was in good agreement with theK
d of 4.8 nM obtained from [3H]-CDP840 binding studies. Both CDP840 and rolipram inhibited the high-affinity binding of [3H]-rolipram binding to PDE-4A, B, C and D with similarK
d app (7–19 nM and 3–5 nM, respectively). Thus, the activity of CDP840 at the [3H]-rolipram binding site was in agreement with the inhibitor’s activity at the catalytic site. However, rolipram was ∼100-fold
more potent than CDP840 at inhibiting the binding of [3H]-rolipram to mouse brain in vivo. These data clearly demonstrate that CDP840 is a potent selective inhibitor of all PDE-4
isoenzymes. In contrast to rolipram, CDP840 was well-tolerated in humans. This difference, however, cannot at present be attributed
to either isoenzyme selectivity or lack of activity in vitro at the high-affinity rolipram binding site (Sr). 相似文献
7.
Dose-related influence of sodium selenite on apoptosis in human thyroid follicles in vitro induced by iodine, EGF, TGF-β, and H2O2 总被引:1,自引:0,他引:1
Lehmann P Rank P Hallfeldt KL Krebs B Gärtner R 《Biological trace element research》2006,112(2):119-130
Apoptosis of thyroid follicular cells is induced by high doses of iodide, epidermal growth factor (EGF), transforming growth
factor-β (TGF-β), as well as H2O2 and might be attenuated by antioxidants. Therefore, we examined the apoptotic index induced by these substances in selenium-treated
vs untreated human thyroid follicular cells. Reconstituted human thyroid follicles were incubated with sodium selenite (10
or 100 nM) for 72 h; controls received none. The follicles were then distributed to 24-well plates and incubated with potassium iodide
(5, 10, or 20 nM), EGF (5 ng/mL), TGF-β (5 ng/mL), or H2O2 (100 μM). Apoptosis was determined by a mitochondrial potential assay and the number of apoptotic cells counted by two independent,
experienced technicians and the glutathione peroxidase (GPx) activity was determined. A significant increase of apoptic cells
was obtained in control thyroid follicles treated with iodine (5, 10, or 20 μM), thyroid-stimulating hormone (TSH) 1, or 10 mU/mL in combination with 5 and 10 μM iodine, EGF (5 ng/mL) and TGF-β (5 ng/mL), or H2O2 (100 μM) (p<0.001). In contrast, in thyroid follicles preincubated with 10 or 100 nM sodium selenite, the apoptototic index was identical to the basal rate. In H2O2-treated follicles, the apoptotic index was still significantly elevated but 50% lower compared to control cells. The GPx
activity increased from 1.4±0.2 to 2.25±0.4 mU/μg DNA with 10 nM selenite and 2.6+0.4 mU/μg DNA with 100 nM selenite. Sodium selenite might increase the antioxidative potential in human thyroid follicles in vitro and therefore diminish
the apoptosis induced by TGF-β, EGF, iodide, and even H2O2 相似文献
8.
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
9.
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
10.
Deborah M. Dickey Robert Aarhus Timothy F. Walseth Hon Cheung Lee 《Cell biochemistry and biophysics》1998,28(1):63-73
Nicotinic acid adenine dinucleotide phosphate (NAADP) is a metabolite of NADP, which can release Ca2+ from stores that are distinct from those activated by either cyclic ADP-ribose or inositol 1,4,5-trisphosphate (IP3). It has previously been suggested that thio-NADP is a specific antagonist of NAADP (Chini et al. [1995]J. Biol. Chem.
270, 3216–3223). Its effects in sea-urchin egg homogenates were investigated. At 50 μM, thio-NADP activates partial Ca2+ release and totally inhibits subsequent challenge with a saturating concentration of NAADP. Purification by HPLC eliminates
the Ca2+ releasing activity of 50 μM thio-NADP and reduces the subsequent inhibition by 73.7±1.3%. The residual inhibitory effect is no more than that exerted
by 50 μM of either NADP itself or nicotinic acid adenine dinucleotide (NAAD). These results are confirmed by32P-NAADP binding studies. Unpurified thio-NADP inhibits the specific32P-NAADP binding to egg microsomes with an IC50 of 40 μM. After HPLC purification, only 20% inhibition is seen at a concentration as high as 50 μM, similar to the extent of inhibition effected by 40 μM NADP. These results indicate the inhibitory substance in thio-NADP is a contaminant. The partial Ca2+ release activity of unpurified thio-NADP suggests the contaminant is NAADP itself. This is supported by the fact that pretreatment
with a subthreshold concentration of only 2 nM NAADP totally desensitizes the egg homogenates such that no Ca2+ response is seen with saturating NAADP. Estimation from the binding studies shows that a contamination of 0.012% of NAADP
in the unpurified thio-NADP samples is sufficient to account for the inhibitory effects. These results indicate thio-NADP
is not an antagonist of NAADP. 相似文献
11.
Wennuan Liu C. Ernie Chilcott Richard C. Reich Gary M. Hellmann 《In vitro cellular & developmental biology. Plant》2000,36(3):201-206
Summary The present work provides a system for regeneration of clary sage, (Salvia sclarea L.) via organogenesis using plant tissue culture techniques in a multistage culturing medium containing 2,4-dichlorophenoxyacetic
acid (2,4-D) (9.05–181.00 μM). A higher frequency of organogenic tissue initiation was obtained from immature zygotic embryo cotyledons (IZEC) 2–3 wk
after pollination on the medium supplemented with 9.05 μM 2,4-D. The organogenic tissues were then proliferated on media containing both indole-3-acetic acid (IAA) and 6-benzylaminopurine
(BA). Organogenic lines were established via selection, isolation and continuous subculture of organogenic tissues on a medium
containing 22.19 μM BA and 2.85 μM IAA. Shoots were regenerated from both the proliferated tissues and IZEC, and propagated in the presence of IAA or α naphthaleneacetic
acid (NAA), BA and gibberellic acid (GA3). Although roots were induced from regenerated shoots on the media containing a low concentration of IAA, IBA (0.98 μM) in combination with desiccation of regenerated shoots with a stem ∼10 mm in length promoted more and stronger root formation.
After the root system was well established (20 mm in length), the regenerated plants were transferred to soil in plastic pots
for further growth and production of R1 seeds in the greenhouse. 相似文献
12.
Tretiakova I Blaesius D Maxia L Wesselborg S Schulze-Osthoff K Cinatl J Michaelis M Werz O 《Apoptosis : an international journal on programmed cell death》2008,13(1):119-131
Myrtucommulone (MC) is a unique, nonprenylated acylphloroglucinol contained in the leaves of myrtle (Myrtus communis). Here, we addressed the potential of MC to induce apoptosis of cancer cells. MC potently induced cell death of different
cancer cell lines (EC50 3–8 μM) with characteristics of apoptosis, visualized by the activation of caspase-3, -8 and -9, cleavage of poly(ADP-ribose)polymerase
(PARP), release of nucleosomes into the cytosol, and DNA fragmentation. MC was much less cytotoxic for non-transformed human
peripheral blood mononuclear cells (PBMC) or foreskin fibroblasts (EC50 cell death = 20–50 μM), and MC up to 30 μM hardly caused processing of PARP, caspase-3, -8 and -9 in human PBMC. MC-induced
apoptosis was mediated by the intrinsic rather than the extrinsic death pathway. Thus, MC caused loss of the mitochondrial
membrane potential in MM6 cells and evoked release of cytochrome c from mitochondria. Interestingly, Jurkat cells deficient
in caspase-9 were resistant to MC-induced cell death and no processing of PARP or caspase-8 was evident. In cell lines deficient
in either CD95 (Fas, APO-1) signalling, FADD or caspase-8, MC was still able to potently induce cell death and PARP cleavage.
Conclusively, MC induces apoptosis in cancer cell lines, with marginal cytotoxicity for non-transformed cells, via the mitochondrial
cytochrome c/Apaf-1/caspase-9 pathway.
I. Tretiakova and D. Blaesius contributed equally to this work. 相似文献
13.
Ze-peng Y Guo-wei L Hong-yu H Yun-yu W Yong-hui S 《Biological trace element research》2005,105(1-3):215-227
This experiment was conducted to investigate the effects of zinc sulfate and zinc methionine (Zn-Met) and their levels on
apoptosis induced by glucocorticoid of thymocytes and the possible mechanism. Dexamethasone was used to make the apoptosis
model of thymocytes; zinc sulfate and zinc methionine were supplemented to the medium at levels of 0,50, 100, 500, and 1000
μM. The activity of cells,Cu,Zn superoxide dismutase (Cu,Zn-SOD), DNA ladder pattern, intracellular calcium concentration, and
the percentage of apoptosis nuclei were determined.
Both ZnSO4 and Zn-Met could modulate apoptosis; they inhibited apoptosis and decreased DNA fragmentation. The regulation was concentration
dependent. At levels of 50 and 100 μM, the effect of Zn-Met on inhibiting apoptosis was less efficient than that of ZnSO4 (p<0.05), but the activity of the cells cultured with Zn-Met was higher than those cultured with ZnSO4; they showed no difference in modulating apoptosis when added at levels of 500 and 1000 μM to the medium (p>0.05). Intracellular calcium concentrations of cells cultured with Zn-Met were higher than those cultured with ZnSO4 at the same levels. Zinc supplementation decreased the concentration of intracellular calcium significantly (p<0.05) and increased the activity of Cu,Zn-SOD in the extract of the cells (p<0.05). Both zinc sulfate and Zn-Met could modulate apoptosis of thymocytes induced by glucocorticoid; the mechanism might
involve the exchange of intracellular calcium, the redox of cells, and the two forms of zinc might go different ways in the
regulations. 相似文献
14.
Doris Marko Konstantinos Romanakis Heinrich Zankl Gerhard Fürstenberger Brigitte Steinbauer Gerhard Eisenbrand 《Cell biochemistry and biophysics》1998,28(2-3):75-101
In order to study potential changes in phosphodiesterase (PDE) activity associated with malignant transformation, normal primary
keratinocytes and cells corresponding to different stages of epidermal tumor development in mouse skin were analyzed with
respect to their 3′,5′-cyclic adenosine monophosphate (cAMP) hydrolyzing activity. Expression of cAMP-specific PDE-4, intracellular
cAMP content, and the sensitivity to the growth inhibitory effect of the PDE-4-specific inhibitor 7-benzylamino-6-chloro-2
piperazino-4-pyrrolidino-pteridine (DC-TA-46) were studied in the two papilloma cell lines, MSCP6 and 308, and in the highly
malignant carcinoma cell line CarB. No significant difference in soluble PDE activity and in intracellular cAMP was found
in the two papilloma cell lines when compared to primary keratinocytes. In contrast, the spindle-cell carcinoma cell line
CarB exhibited significantly higher PDE activity, concomitant with the lowest cAMP level. In all cell lines and also in the
primary keratinocytes, rolipram-sensitive PDE-4 activity accounted for the major cAMP-hydrolyzing activity. In primary keratinocytes
and in MSCP6 cells, the PDE-4 inhibitor DC-TA-46 induced at best marginal growth inhibition, whereas cell growth of 308 cells
was markedly affected at concentrations >2 μM. The carcinoma cell line CarB showed the highest sensitivity to DC-TA-46 (IC50=0.8±0.3 μM). Treatment of CarB cells with DC-TA-46 strongly inhibits intracellular PDE activity, resulting in a marked and long-lasting
rise of cAMP. After 24 h of treatment, arrest in the G0/G1 phase of the cell cycle is induced. Treatment with concentrations >2 μM of this highly effective PDE inhibitor results in induction of apoptotic cell death, as detected by fluorescence microscopy,
flow cytometry, and ELISA-based determination of fragmented DNA in intact cells. 相似文献
15.
Using the whole-cell patch-clamp technique, the selectivity and pharmacology of 8-Br-cGMP-stimulated currents in the human
alveolar cell line A549 was compared to 8-Br-cGMP-stimulated currents in HK293 cells transfected with hαCNC1. Whole cell currents
stimulated by 8-Br-cGMP in HK293 cells transfected with hαCNC1 or A549 cells are carried by inward sodium and outward potassium
with nearly the same selectivity. The whole-cell inward currents that are stimulated by 8-Br-cGMP in HK293 cells transfected
with hαCNC1 are inhibited by l-cis-diltiazem with an IC50 of 154 μm, by 2′,4′-dichlorobenzamil with an IC50 of 50 μm and by amiloride with an IC50 of 133 μm. The whole-cell inward currents in A549 cells that are stimulated by 8-Br-cGMP, are inhibited by l-cis-diltiazem with an
IC50 of 87 μm, by 2′4′-dichlorobenzamil with an IC50 of 38 μm and by amiloride with an IC50 of 32 μm suggesting that these airway cells contain cyclic nucleotide-gated cation channels. RT-PCR data suggest that mRNA of both
αCNC1 and βCNC subunits are present in A549 cells and the presence of the βCNC subunit, may as previously reported, increase
the affinity of these channel blockers compared to the hαCNC1 subunit alone. The mRNA of two other isoforms of this channel,
CNC2 and CNC3, are also expressed in the A549 cell line. This study documents the IC50 of externally applied channel blockers that can be used for in vitro or in vivo experiments to document sodium absorption
via cyclic nucleotide-gated cation channels in airway cells.
Received: 24 February/Revised: 28 May 1999 相似文献
16.
Suleiman A. Suleiman Jeffrey B. Stevens 《In vitro cellular & developmental biology. Plant》1987,23(5):332-338
Summary Cell viability, cytochrome P-450 content, cell respiration, and lipid peroxidation were all investigated as a function of
oxygen tension in adult rat hepatocytes in short-term culture (less than 9 h). The various oxygen tensions used in this study
were obtained by equilibrating culture medium with air, air + nitrogen, or air + oxygen. Cell viability, as assessed by trypan
blue exclusion, was significantly greater at all time points tested when hepatocytes were cultured in Ham's F12 medium containing
132 μM O2, as compared to medium equilibrated with air (220 μM O2) or air + oxygen (298 μM O2). Cells cultured in 220 μM O2 (air) also exhibited a gradual loss of cytochrome P-450, so that by 9 h of incubation less than 60% of the active material
remained. This loss of P-450 was minimized when cells were cultured in 163 μM O2 and abolished when cells were cultured in 132 μM O2. The 132 μM O2 exposure conditions also maintained cell respiration at the 1 h incubation values, whereas there was a continuous loss in
cell respiration over time when the cells were cultured in either 220 μM O2 (air) or 298 μM O2 (air:O2). These cytotoxicity findings may be related to oxidative cell damage inasmuch as it was additionally demonstrated that lipid
peroxidation (as measured by malondieldehyde equivalents) was consistantly lower in hepatocytes cultured in air:N2 as compared to air or air:O2. These results suggest that hepatocyte culture in low oxygen tension improves not only cell viability but also maintains
other functional characteristics of the cell.
This work was supported by a Biomedical Research Support Grant S-S07-RR 05448 awarded to the University of Minnesota School
of Public Health by the Biomedical Research Grant Program, Division of Research and Resources, National Institutes of Health,
Bethesda, MD. 相似文献
17.
Terry L. Riss Betty H. Stewart David A. Sirbasku 《In vitro cellular & developmental biology. Plant》1989,25(2):127-135
Summary The growth of GH4C1, GH3, GH1, and GH3C15 rat pituitary tumor cell lines was studied in a serum-free medium (designated TRM-1) formulated with 1∶1 (vol/vol) mixture
of Ham's F12 nutrient mixture and Dulbecco's modified Eagle's medium (F12-DME) containing 15 mM 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES), 50 μg/ml gentamicin supplemented with 10 μg/ml bovine insulin,
10 μg/ml human transferrin (Tf), 10 ng/ml selenous acid, 10 nM 3,5,3′-triiodothyronine (T3), 50 μM ethanolamine (Etn), and 500 μg/ml bovine serum albumin. Of the lines evaluated, only the GH1 failed to grow in TRM-1. Passage of the GH4C1 and GH3 lines from serum-containing medium into TRM-1 caused an initial selection resulting in cells that grew progressively at higher
rates and finally were maintained indefinitely in TRM-1. These populations showed a requirement for supraphysiologic concentrations
of T3 (1.0 to 10 nM). After adaptation of the GH4C1 line in TRM-1 for ≤20 generations, removal of components gave a less complex mixture containing 15 mM HEPES, 50 μ/ml gentamicin, 10 μg/ml Tf, 10 nM T3, and 50 μM Etn (designated TRM-2) that supported serial passage of the cells. Under these conditions, thyroid hormone dependence was
lost progressively. When T3 was removed from TRM-2 adapted cells, a third population was selected that no longer required thyroid hormones and was only
slightly stimulated by T3. These studies demonstrated that the combination of serum-containing and serum-free conditions can be used to select pituitary
cell populations that a) required both serum-factor(s) and T3 for optimum growth, b) required supraphysiologic concentrations of T3 without serum proteins other than Tf and albumin, and c) were completely autonomous in that they proliferated in medium supplemented
only with Tf and nutrients without necessity of other serum factor(s) or T3.
This work was supported by grants CA-26617 and CA-38024 from the National Cancer Institute, Bethesda, MD, American Cancer
Society grant BC-255, and grant 2225 from the Council for Tobacco Research, Inc., USA. 相似文献
18.
Dilip K. Das Prasanna Bhomkar N. Shiva Prakash Neera Bhalla-Sarin 《In vitro cellular & developmental biology. Plant》2002,38(5):456-459
Summary A very rapid and efficient regeneration method of Vigna mungo L. has been established using liquid culture. A highly regenerable explant, viz., young multiple shoots obtained by germinating
the seeds in 2 mgl−1 (8.9μM) N6-benzyladenine-supplemented Murashige and Skoog (MS) medium, was used as a source of tissue to initiate the liquid culture.
The liquid medium consisted of half-strength B5 or MS salts supplemented with MS organics, α-naphthaleneacetic acid (0.1 mgl−1, 0.54μM) and N6-benzyladenine (0.5mgl−1, 2.2μM). Transferring the growing tissues to fresh medium every third day resulted in ca. 142% increase in the number of shoot buds produced after 24d. Shoot buds elongated on one-third-strength MS (MS1/3) semisolid medium and plantlets were obtained by transferring the shoots onto MS1/3 semisolid medium supplemented with indolebutyric acid (1 mgl−1, 4.9 μM). 相似文献
19.
Cerovic A Miletic I Sobajic S Blagojevic D Radusinovic M El-Sohemy A 《Biological trace element research》2007,116(1):61-71
Zinc is an important mineral that is required for normal bone development. However, the direct effects of zinc on the mineralization
of bone cells of human origin are not clear. The objective of this study was to determine the effects of zinc on the differentiation
of SaOS-2 human osteoblast-like cells and the formation of mineralized bone nodules. Cells were cultured for 8 d and then
transferred to zinc-free medium and treated with varying concentrations (0–50 μM) of zinc. Alkaline phosphatase (ALP) activity was used as a measure of osteoblast differentiation, and bone nodules were
detected by von Kossa staining. After 4, 6, and 8 d of treatment, zinc increased ALP activity at 1 and 10 μM, but decreased activity at 50 μM. After 9 d of treatment, zinc increased both the number and area of mineralized bone nodules at low concentrations (1 and
10 μM), but decreased both at higher concentrations (25 and 50 μM). These findings demonstrate that zinc has biphasic effects on the differentiation and mineralization of human osteoblast-like
cells. 相似文献
20.
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