共查询到20条相似文献,搜索用时 15 毫秒
1.
James C K Lai Maria B Lai Sirisha Jandhyam Vikas V Dukhande Alok Bhushan Christopher K Daniels Solomon W Leung 《International journal of nanomedicine》2008,3(4):533-545
The use of titanium dioxide (TiO2) in various industrial applications (eg, production of paper, plastics, cosmetics, and paints) has been expanding thereby increasing the occupational and other environmental exposure of these nanoparticles to humans and other species. However, the health effects of exposure to TiO2 nanoparticles have not been systematically assessed even though recent studies suggest that such exposure induces inflammatory responses in lung tissue and cells. Because the effects of such nanoparticles on human neural cells are unknown, we have determined the putative cytotoxic effects of these nanoparticles on human astrocytes-like astrocytoma U87 cells and compared their effects on normal human fibroblasts. We found that TiO2 micro- and nanoparticles induced cell death on both human cell types in a concentration-related manner. We further noted that zinc oxide (ZnO) nanoparticles were the most effective, TiO2 nanoparticles the second most effective, and magnesium oxide (MgO) nanoparticles the least effective in inducing cell death in U87 cells. The cell death mechanisms underlying the effects of TiO2 micro- and nanoparticles on U87 cells include apoptosis, necrosis, and possibly apoptosis-like and necrosis-like cell death types. Thus, our findings may have toxicological and other pathophysiological implications on exposure of humans and other mammalian species to metallic oxide nanoparticles. 相似文献
2.
A protocol for the in vitro propagation of Drosera aliciae to increase the yield of the naphthoquinone, ramentaceone, was developed. The highest micropropagation coefficient was obtained
using half-strength Murashige–Skoog medium supplemented with 0.4 μM 6-benzyladenine (BA). The genetic fidelity and stability
of the regenerated plants was confirmed with RAPD markers. The activity of the isolated ramentaceone was determined against
four human tumor cell lines: U937, HeLa, MCF-7, HCT-116 with the highest cytotoxic activity towards the leukemic U937 cell
line with an IC50 value of 3.2 μM. 相似文献
3.
Maria-Eleni Androutsou Mahmoud Saifeddine Morley D. Hollenberg John Matsoukas George Agelis 《Amino acids》2010,38(4):985-990
In the present study, we report the synthesis and biological evaluation of a series of new non-peptide PAR1 mimetic receptor antagonists, based on conformational analysis of the S42FLLR46 tethered ligand (TL) sequence of PAR1. These compounds incorporate the key pharmacophore groups in the TL sequence, guanidyl, amino and phenyl, which are essential
for triggering receptor activity. Compounds 5 and 15 (50–100 μM) inhibited both TFLLR-amide (10 μM) and thrombin-mediated (0.5 and 1 U/ml; 5 and 10 μM) calcium signaling in a
cultured human HEK cell assay. 相似文献
4.
Priyanka Srivastava Naresh Kasoju Utpal Bora Rakhi Chaturvedi 《Plant Cell, Tissue and Organ Culture》2009,99(1):1-7
Several secondary metabolites are present in Lantana camara L. as its leaves serve as reservoirs for various bioactive compounds. Callus cultures of L. camara were induced from leaf discs incubated on Murashige and Skoog medium supplemented with 5 μM 6-benzyladenine, 1 μM 2,4-dichlorophenoxyacetic
acid, and 1 μM α-naphthalene acetic acid (NAA). An aqueous extract (0.23%), obtained from these calli (50 g dry mass), had
an apparent cytotoxic effect on HeLa cells with an IC50 value of 1,500 μg/ml in 36 h. A dose-time dependent activity of the extract was established wherein higher dosage exhibited
increased activity; however, over time cell necrosis was observed. 相似文献
5.
Hélio V. Nobre-Júnior Ricardo A. Oliveira Flavio D. Maia Marcelle A. S. Nogueira Manoel Odorico de Moraes Mary Anne M. Bandeira Geanne M. Andrade Glauce S. B. Viana 《Neurochemical research》2009,34(6):1066-1075
In the present work, we showed that a chalcone-enriched fraction (CEF) isolated from the stem bark of a Brazilian medicinal
plant, Myracrodruon
urundeuva, presents neuroprotective actions on 6-hydroxydopamine (6-OHDA)-induced neuronal cell death, in rat mesencephalic cells.
In the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium] assay, which is an index of cell viability, CEF (1–100 μg/ml)
reversed in a concentration-dependent manner the 6-OHDA-induced cell death. While cells exposed to 6-OHDA (40 μM) showed an
increased concentration of thiobarbituric acid reactive substances (TBARS), the pretreatment with CEF (10–100 μg/ml) significantly
decreased the 6-OHDA-induced TBARS formation, indicative of a neuroprotection against lipoperoxidation. Furthermore, the drastic
increase of nitrite levels induced by 6-OHDA, indicative of nitric oxide formation and free radicals production, was prevented
by CEF. Double staining with acridine orange/ethidium bromide showed that cultures exposed to 6-OHDA (40 and 200 μM) presented
an increase of apoptotic and necrotic cell numbers in a concentration-dependent manner. CEF (100 μg/ml) protected cells from
apoptosis and necrosis and increased number of cells presenting a normal morphology. The immunohistochemical analysis for
tyrosine hydroxylase (TH) positive neurons indicated that 6-OHDA (40 and 200 μM) caused a concentration-dependent loss of
TH+ and TH− neurons. CEF protected both cells types from 6-OHDA-induced cell death. All together, our results demonstrated
neuroprotective effects of chalcones, which are able to reduce oxidative stress and apoptotic injury caused by 6-OHDA. Our
findings suggest that chalcones could provide benefits, along with other therapies, in neurodegenerative injuries, such as
Parkinson’s disease. 相似文献
6.
In vitro release behavior and cytotoxicity of doxorubicin-loaded gold nanoparticles in cancerous cells 总被引:1,自引:0,他引:1
Doxorubicin (DOX), a common cancer chemotherapeutics, was conjugated to folate-modified thiolated-polyethylene glycol-functionalized
gold nanoparticles. The in vitro, controlled release behavior of DOX-loaded gold nanoparticles was observed using porous dialysis
membranes (cut-off = 2 kDa). DOX-loaded gold nanoparticles had higher cytotoxicity for folate-receptor-positive cells (KB
cells) compared to folate-receptor-negative cells (A549 cells) which were 48 and 62% viable for 10 μM doxorubicin, respectively.
This indicates the potential of these nano-carriers for targeted-delivery. In addition, healthy cell viability was 69% for
10 μM free doxorubicin whereas for the same content of drug in DOX-loaded nanoparticles healthy cell viability increased to
80%. 相似文献
7.
Antibacterial activity of ZnO nanoparticles prepared via non-hydrolytic solution route 总被引:1,自引:0,他引:1
Rizwan Wahab Amrita Mishra Soon-Il Yun Young-Soon Kim Hyung-Shik Shin 《Applied microbiology and biotechnology》2010,87(5):1917-1925
The antibacterial activity of ZnO nanoparticles has been investigated and presented in this paper. Nanoparticles were prepared
via non-hydrolytic solution process using zinc acetate di-hydrate (Zn(CH3COO)2·2H2O) and aniline (C6H5NH2) in 6 h refluxing at ∼65 °C. In the presence of four pathogens such as Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, and Klebsiella pneumoniae, the antibacterial study of zinc oxide nanoparticles were observed. The antibacterial activity of ZnO nanoparticles (ZnO-NPs) were studied by spectroscopic method taking different concentrations
(5–45 μg/ml) of ZnO-NPs. Our investigation reveals that the lowest concentration of ZnO-NPs solution inhibiting the growth
of microbial strain is found to be 5 μg/ml for K. pneumoniae, whereas for E. coli, S. aureus, and S. typhimurium, it was calculated to be 15 μg/ml. The diameter of each ZnO-NPs lies between “20 and 30 nm” as observed from FESEM and transmission
electron microscopy images. The composition of synthesized material was analyzed by the Fourier transform infrared spectroscopy,
and it shows the band of ZnO at 441 cm−1. Additionally, on the basis of morphological and chemical observations, the chemical reaction mechanism of ZnO-NPs was also
proposed. 相似文献
8.
Ling Li Jun Qin Qiang Feng Hao Tang Rong Liu Liqing Xu Zhinan Chen 《Molecular biotechnology》2011,47(1):9-17
While heparin has been shown to eliminate cell aggregation in suspension adaptations of insect and HEK293 cells for virus-based
cell cultures, the role of heparin in long period serum-free suspension adaptation of the anchorage-dependent Chinese hamster
ovary (CHO) cell lines remains inconclusive. In this paper, we explore the potential application of heparin in suspension
adaptation of CHO cell line which produces an anti-human chimeric antibody cHAb18. Heparin showed a concentration-dependent
inhibition of CHO–TS28 cell-to-cell adhesion, with a significant inhibitory effect occurring when the concentration exceeded
250 μg/ml (P < 0.001). Heparin also exhibited a cell aggregation elimination role at all concentrations (P < 0.001). Furthermore, heparin promoted cell growth and antibody secretion, with the highest cell density ((99.83 ± 12.21) × 104 cells/ml, P = 0.034) and maximum antibody yield ((9.46 ± 0.94) mg/l, P < 0.001) both occurring at 250 μg/ml heparin. When agitated, cell aggregates were effectively dispersed by 250 μg/ml heparin
and a single-cell suspension culture process was promoted. In suspension adapted CHO–TS28 cells, cell growth rates and specific
antibody productivity were maintained; while antigen-binding activity improved slightly. Together, our results show that heparin
may promote suspension adaptation of anchorage-depended CHO cells by resisting cell aggregation without reducing cell growth,
antibody secretion, and antigen-binding activity. 相似文献
9.
The mechanisms of protective effect of N-methyl-D-aspartate (NMDA) receptor stimulation on apoptosis of neurons at their early
stage of development are poorly understood. In the present study, we investigated the effects of NMDA on staurosporine (St)-
and low-potassium (LP)-evoked apoptotic cell death in primary cerebellar granule cell (CGC) cultures at 7 days in vitro (DIV).
We found that NMDA (200 μM) attenuated the St (0.5 μM)- and LP (5 mM KCl)-induced neuronal cell death in 7 but not 12 DIV
CGC as confirmed by LDH release and MTT reduction assays. Moreover, NMDA attenuated St-and LP-evoked DNA fragmentation and
cytosolic apoptosis inducing factor (AIF) protein level but not caspase-3 activation induced by both pro-apoptotic factors.
Neuroprotective effects of NMDA on St-induced apoptosis in CGC were attenuated by inhibitors of ERK/MAPK-signaling, PD 98059
and U0126 but not by NMDA receptor antagonists, AP-5 (100 μM) and MK-801 (1 μM) or by inhibitors of PI3-K/Akt pathway (LY
294002 and wortmannin). In contrast to staurosporine model of apoptosis, AP-5 and MK-801 but not inhibitors of PI3-K/Akt and
MAPK/ERK1/2 prevented the NMDA-mediated neuroprotection in LP-induced apoptosis of CGC. In separate experiments, we observed
also the anti-apoptotic action of NMDA on St (0.5 μM)- and salsolinol (250 μM)-evoked cell death in human neuroblastoma SH-SY5Y
cells without its influence on caspase-3 activity, induced by these pro-apoptotic factors. These data indicate that neuroprotection
evoked by NMDA in CGC strongly depends on used pro-apoptotic agent and could engage NMDA channel function or be connected
with the activation of pro-survival MAPK/ERK1/2 pathway. It is also suggested that anti-apoptotic effects of NMDA is connected
with inhibition of fragmentation of DNA via caspase-3-independent mechanism. 相似文献
10.
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
11.
The present study aimed to investigate the effect of ZnO nanoparticles on alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) enzyme expressions in C2C12 cells. ZnO nanoparticles are widely used in the several cosmetic lotions and other biomedical products. Several studies report on ZnO nanoparticle mediated cytotoxicity. However, there are no reports on the effect of ZnO nanoparticles on ALT, AST, ALP and LDH enzyme expressions in C2C12 cells. A cytotoxicity assay was carried out to determine the effect of ZnO nanoparticles (1–5 mg/ml) on C2C12 cell viability at 48 and 72 h. ZnO nanoparticles increased ALT, AST, ALP and LDH enzyme mRNA expression and their activities in C2C12 cells. In conclusion, the present study showed that ZnO nanoparticles increased these enzyme activities and its mRNA expression in C2C12 cells in a dose-dependent manner. 相似文献
12.
l-Arginine stimulates proliferation and prevents endotoxin-induced death of intestinal cells 总被引:1,自引:0,他引:1
Bie Tan Yulong Yin Xiangfeng Kong Peng Li Xilong Li Haijun Gao Xinguo Li Ruilin Huang Guoyao Wu 《Amino acids》2010,38(4):1227-1235
This study tested the hypothesis that l-arginine (Arg) may stimulate cell proliferation and prevent lipopolysaccharide (LPS)-induced death of intestinal cells. Intestinal
porcine epithelial cells (IPEC-1) were cultured for 4 days in Arg-free Dulbecco’s modified Eagle’s-F12 Ham medium (DMEM-F12)
containing 10, 100 or 350 μM Arg and 0 or 20 ng/ml LPS. Cell numbers, protein concentrations, protein synthesis and degradation,
as well as mammalian target of rapamycin (mTOR) and Toll-like receptor 4 (TLR4) signaling pathways were determined. Without
LPS, IPEC-1 cells exhibited time- and Arg-dependent growth curves. LPS treatment increased cell death and reduced protein
concentrations in IPEC-1 cells. Addition of 100 and 350 μM Arg to culture medium dose-dependently attenuated LPS-induced cell
death and reduction of protein concentrations, in comparison with the basal medium containing 10 μM Arg. Furthermore, supplementation
of 100 and 350 μM Arg increased protein synthesis and reduced protein degradation in both control and LPS-treated IPEC-1 cells.
Consistent with the data on cell growth and protein turnover, addition of 100 or 350 μM Arg to culture medium increased relative
protein levels for phosphorylated mTOR and phosphorylated ribosomal protein S6 kinase-1, while reducing the relative levels
of TLR4 and phosphorylated levels of nuclear factor-κB in LPS-treated IPEC-1 cells. These results demonstrate a protective
effect of Arg against LPS-induced enterocyte damage through mechanisms involving mTOR and TLR4 signaling pathways, as well
as intracellular protein turnover. 相似文献
13.
Ansari MA Khan HM Khan AA Sultan A Azam A 《Applied microbiology and biotechnology》2012,94(2):467-477
The reemergence of infectious diseases and the continuous development of multidrug resistance among a variety of disease-causing
bacteria in clinical setting pose a serious threat to public health worldwide. Extended-spectrum β-lactamases (ESBLs) that
mediate resistance to third-generation cephalosporin are now observed all over the world in all species of Enterobacteriaceae,
especially Escherichia coli and Klebsiella pneumoniae. In this work, ZnO nanoparticles (NPs) were synthesized by the sol–gel method and characterized by powder X-ray diffraction,
scanning electron microscopy (SEM) and atomic force microscopy (AFM). The image of synthesized ZnO NPs appeared spherical
in SEM with a diameter of ≈19 nm and as hexagonal crystal in AFM. Clinical isolates were assessed for ESBL production and
shown to be sensitive to ZnO NPs by different methods such as minimal inhibitory concentration (MIC) and minimal bactericidal
concentration, time-dependent growth inhibition assay, well diffusion agar methods and estimation of colony forming units
(CFU) of bacteria. The lowest MIC value for E. coli and K. pneumoniae was found to be 500 μg/ml. The results showed that ZnO NPs at 1,000 μg/ml completely inhibit the bacterial growth. The antibacterial
effect of ZnO nanoparticles was gradual, but time- and concentration-dependent. The maximum inhibition zone at100 μg/ml for
E. coli and K. pneumoniae was 22 and 20 mm, respectively. With the increasing ZnO NP loading, there is significant reduction in the numbers of CFU.
At the concentration of 1,000 μg/ml, the decline in per cent survival of E. coli and K. pneumoniae was found to be 99.3% and 98.6%, respectively. 相似文献
14.
The cytotoxicity of the oxysterols 25-hydroxycholesterol, 7β-hydroxycholesterol, cholesterol-5α,6α-epoxide, cholesterol-5β,6β-epoxide,
19-hydroxycholesterol and 7-ketocholesterol was examined in U937 cells, a human monocytic blood cell line. 7β-Hydroxycholesterol,
cholesterol-5β,6β-epoxide, and 7-ketocholesterol, at 30 μmol/L concentration, were found to be cytotoxic to this cell line
and the mode of cell death was by apoptosis. 25-Hydroxycholesterol, cholesterol-5α,6α-epoxide and 19-hydroxycholesterol (30
μmol/L) did not induce apoptosis in this cell line. Since it has been suggested that the generation of an oxidative stress
may occur in the early stages of the apoptotic process, the glutathione concentration and the activity of superoxide dismutase
were also measured in the oxysterol-treated cells. 7β-Hydroxycholesterol was shown to increase the superoxide dismutase activity
and decrease the glutathione concentration. However, cholesterol-5β,6β-epoxide and 7-ketocholesterol, which were also shown
to induce apoptosis, did not affect the glutathione concentration or the superoxide dismutase activity in the U937 cells.
Therefore, oxysterol-induced apoptosis may not be dependent on the generation of an oxidative stress.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
15.
Chlorination is widely used method in the disinfection of drinking and utility water worldwide. In this study, cytotoxic and
genotoxic effects of sodium hypochlorite were investigated by the cytokinesis-block micronucleus assay and chromosomal aberration
analysis on human peripheral lymphocytes in vitro. A significant increase in chromosomal aberration frequency was observed
in all treatments of NaOCl (0.030, 0.065, 0.100, 0.25, 0.5, 1, 2, 4 μg/mL) at 24 and 48 h compared with the negative control
and mitomycin C (MMC, 0.3 μg/mL), which was used as a positive control. NaOCl significantly increased the frequency of micronuclei
in a dose dependent manner. The results showed that there was a significant correlation between NaOCl concentration and chromosomal
aberration, micronuclei frequency, necrotic cells, apoptotic cells and binucleated cells. 相似文献
16.
Wen-Ru Li Xiao-Bao Xie Qing-Shan Shi Shun-Shan Duan You-Sheng Ouyang Yi-Ben Chen 《Biometals》2011,24(1):135-141
The antibacterial activity and mechanism of silver nanoparticles (Ag-NPs) on Staphylococcus aureus ATCC 6538P were investigated in this study. The experiment results showed the minimum bactericidal concentration (MBC) of
Ag-NPs to S. aureus was 20 μg/ml. Moreover, when bacteria cells were exposed to 50 μg/ml Ag-NPs for 6 h, the cell DNA was condensed to a tension
state and could have lost their replicating abilities. When S. aureus cells were exposed to 50 μg/ml Ag-NPs for 12 h, the cell wall was breakdown, resulting in the release of the cellular contents
into the surrounding environments, and finally became collapsed. And Ag-NPs could reduce the enzymatic activity of respiratory
chain dehydrogenase. Furthermore, the proteomic analysis showed that the expression abundance of some proteins was changed
in the treated bacterial cell with Ag-NPs, formate acetyltransferase increased 5.3-fold in expression abundance, aerobic glycerol-3-phosphate
dehydrogenase decreased 6.5-fold, ABC transporter ATP-binding protein decreased 6.2-fold, and recombinase A protein decreased
4.9-fold. 相似文献
17.
Wide applications and extreme potential of metal oxide nanoparticles (NPs) increase occupational and public exposure and may
yield extraordinary hazards for human health. Exposure to NPs has a risk for dysfunction of the vascular endothelial cells.
The objective of this study was to assess the cytotoxicity of six metal oxide NPs to human cardiac microvascular endothelial
cells (HCMECs) in vitro. Metal oxide NPs used in this study included zinc oxide (ZnO), iron(III) oxide (Fe2O3), iron(II,III) oxide (Fe3O4), magnesium oxide (MgO), aluminum oxide (Al2O3), and copper(II) oxide (CuO). The cell viability, membrane leakage of lactate dehydrogenase, intracellular reactive oxygen
species, permeability of plasma membrane, and expression of inflammatory markers vascular cell adhesion molecule-1, intercellular
adhesion molecule-1, macrophage cationic peptide-1, and interleukin-8 in HCMECs were assessed under controlled and exposed
conditions (12–24 h and 0.001–100 μg/ml of exposure). The results indicated that Fe2O3, Fe3O4, and Al2O3 NPs did not have significant effects on cytotoxicity, permeability, and inflammation response in HCMECs at any of the concentrations
tested. ZnO, CuO, and MgO NPs produced the cytotoxicity at the concentration-dependent and time-dependent manner, and elicited
the permeability and inflammation response in HCMECs. These results demonstrated that cytotoxicity, permeability, and inflammation
in vascular endothelial cells following exposure to metal oxide nanoparticles depended on particle composition, concentration,
and exposure time. 相似文献
18.
Human epidermal keratinocytes (HEK) are skin cells of primary importance in maintaining the body’s defensive barrier and are
used in vitro to assess the irritation potential and toxicity of chemical compounds. Microfluidic systems hold promise for
high throughput irritant and toxicity assays, but HEK growth kinetics have yet to be characterized within microscale culture
chambers. This research demonstrates HEK patterning on microscale patches of Type I collagen within microfluidic channels
and maintenance of these cells under constant medium perfusion for 72 h. HEK were shown to maintain 93.0%–99.6% viability
at 72 h under medium perfusion ranging from 0.025–0.4 μl min−1. HEK maintained this viability while ∼100% confluent—a level not possible in 96 well plates. Microscale HEK cultures offer
the ability to precisely examine the morphology, behavior and viability of individual cells which may open the door to new
discoveries in toxicological screening methods and wound healing techniques. 相似文献
19.
Wen-Ru Li Xiao-Bao Xie Qing-Shan Shi Hai-Yan Zeng You-Sheng OU-Yang Yi-Ben Chen 《Applied microbiology and biotechnology》2010,85(4):1115-1122
The antibacterial activity and acting mechanism of silver nanoparticles (SNPs) on Escherichia coli ATCC 8739 were investigated in this study by analyzing the growth, permeability, and morphology of the bacterial cells following
treatment with SNPs. The experimental results indicated 10 μg/ml SNPs could completely inhibit the growth of 107 cfu/ml E. coli cells in liquid Mueller–Hinton medium. Meanwhile, SNPs resulted in the leakage of reducing sugars and proteins and induced
the respiratory chain dehydrogenases into inactive state, suggesting that SNPs were able to destroy the permeability of the
bacterial membranes. When the cells of E. coli were exposed to 50 μg/ml SNPs, many pits and gaps were observed in bacterial cells by transmission electron microscopy and
scanning electron microscopy, and the cell membrane was fragmentary, indicating the bacterial cells were damaged severely.
After being exposed to 10 μg/ml SNPs, the membrane vesicles were dissolved and dispersed, and their membrane components became
disorganized and scattered from their original ordered and close arrangement based on TEM observation. In conclusion, the
combined results suggested that SNPs may damage the structure of bacterial cell membrane and depress the activity of some
membranous enzymes, which cause E. coli bacteria to die eventually. 相似文献
20.
The aim of the present studies was to characterise cell death following inhibition of mitochondrial complex I with rotenone
in a transformed cell line (RGC-5 cells) and to examine the neuroprotective properties of the flavonoids genistein, epigallocatechin
gallate (EGCG), epicatechin (EC) and baicalin. Rotenone-induced cell death of RGC-5 cells results in a generation of reactive
oxygen species, a breakdown of DNA, the translocation of membrane phosphatidylserine, an up-regulation of haemoxygenase-1
and is unaffected by necrostatin-1 (inhibitor of necroptosis), z-VAD-fmk (pan caspase inhibitor) or NU1025 (PARP inhibitor)
but attenuated with SP600125 (JNK inhibitor). Rotenone-induced toxicity of RGC-5 cells also caused an activation of mitogen-activated
kinases indicated by an up-regulation and translocation into mitochondria of p-c-Jun, pJNK and pp38. Exposure of RGC-5 cells
to rotenone does not affect apoptosis inducing factor or significantly stimulate caspase-3 activity. EGCG and EC both significantly
blunt rotenone toxicity of RGC-5 cells at concentrations of 50 μM while genistein and baicalin were without effect. Significantly,
genistein is approximately 20 times less efficacious than EGCG (IC50 2.5 μM) and EC (IC50 1.5 μM) at inhibiting sodium nitroprusside-induced lipid peroxidation. These studies show that rotenone toxicity of RGC-5
cells is neither necroptosis nor caspase-dependent apoptosis but involves the activation of mitogen-activated kinases and
is inhibited by a JNK inhibitor, EGCG and EC. Genistein attenuates lipid peroxidation less efficaciously than EC and EGCG
and does not affect rotenone toxicity of RGC-5 cells. 相似文献