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1.
Vernolate (S-propyl N, N-dipropylthiocarbamate) has been used to select thiocarbamate-tolerant tobacco cell lines. Cross-tolerance to other thiocarbamate herbicides was observed. Tolerance was initially unstable in the absence of continued selection, but shoot regeneration produced plants in which some tolerance was stably expressed. Morphological abnormalities in the regenerated plants are described.  相似文献   

2.
Some cancer cells can survive under glucose deprivation within the microenvironment of a tumor. Recently, we reported that N-linked (β-N-acetylglucosamine)2 [N-GlcNAc2]-modified proteins induce G2/M arrest and cell death under glucose deprivation. Here, we investigated whether such a response to glucose deprivation contributes to the survival of renal cell carcinomas, which are sensitive to nutritional stress. Specifically, we analyzed seven renal carcinoma cell lines. Four of these cell lines produced N-GlcNAc2-modified proteins and led G2/M-phase arrest under glucose deprivation, leading to cell death. The remaining three cell lines did not produce N-GlcNAc2-modified proteins and undergo G1/S-phase arrest under glucose deprivation, leading to survival. The four dead cell lines displayed significant up-regulation in the UDP-GlcNAc biosynthesis pathway as well as increased phosphorylation of p53, which was not observed in the surviving three cell lines. In addition, the four dead cell lines showed prolonged up-regulated expression of ATF3, which is related to unfolded protein response (UPR), while the surviving three cell lines showed only transient up-regulation of ATF3. In this study, we demonstrated that the renal carcinoma cells which accumulate N-GlcNAc2-modified proteins under glucose deprivation do not survive with abnormaly prolonged UPR pathway. By contrast, renal carcinoma cells that do not accumulate N-GlcNAc2-modified proteins under these conditions survive. Morover, we demonstrated that buformin, a UPR inhibitor, efficiently reduced cell survival under conditions of glucose deprivation for both sensitive and resistant phenotypes. Further studies to clarify these findings will lead to the development of novel chemotherapeutic treatments for renal cancer.  相似文献   

3.
Inhibitory effects of lactic acid bacteria for dairy use on the mutagenicities of some volatile nitrosamines were investigated in vitro using a Salmonella typhimurium TA 98 streptomycin-dependent strain (SD 510) as an indicator bacterium. Among 40 strains examined, Leuconostoc paramesenteroides R-62, R-8, Streptococcus lactis subsp. diacetylactis R-63, and St. cremoris R-48 strongly inhibited the mutagenicity of N-nitroso-diethylamine (NDEA) and moderately N-nitroso-dimethylamine (NDMA), but not N-nitroso-piperidine (NPIP) or N-nitroso-pyrrolidine (NPYR). In addition, the filtrates obtained from cell suspensions of the lactic acid bacteria examined inhibited the mutagenicity of NDEA.  相似文献   

4.
The interactions of the heteroallenes CO2, OCS, and CS2 with (Me2N)2Sn have been investigated. These CX2 species insert into the Sn-N bonds under mild conditions to provide products bis-(N,N-dimethylcarbamato)tin(II), [(Me2NCO2)2Sn]2, bis-(N,N-dimethylthiocarbamato)tin(II), [Me2NC(O)S]2Sn and bis-(N,N-dimethyldithiocarbamato)tin(II), (Me2NCS2)2Sn. These molecules have been fully characterized by traditional spectroscopic methods as well as by X-ray crystallography. The [Me2NC(O)S]2Sn product is the first example of a structurally characterized Sn(II) thiocarbamate. The solid-state structures of the final products vary depending on the heteroallene inserted. The CO2-inserted product is dimeric in the solid-state, with both bridging and chelating carbamate ligands. These dimers form a chain-like network via intermolecular Sn?O interactions. The monomeric thiocarbamate also shows a chain-like extended structure, through both Sn?O and Sn?S interactions, while the dithiocarbamate product has no significant intermolecular contacts.  相似文献   

5.
Purification and N-terminal analyses of algal biliproteins   总被引:1,自引:0,他引:1       下载免费PDF全文
1. R-, B- and C-phycoerythrins and R- and C-phycocyanins were isolated and purified on a preparative scale by calcium phosphate chromatography, ammonium sulphate fractionation and crystallization. 2. The N-terminal residues of these biliproteins were analysed. Methionine is the only N-terminal residue of all the phycoerythrins, there being about 14 N-terminal residues per molecule of R- and B-phycoerythrins (mol.wt. 290000) and about 8 per molecule of C-phycoerythrin (mol.wt. 226000). Threonine (1 residue) is N-terminal in C-phycocyanin (mol.wt. 138000), and both threonine (about 1·3 residues) and methionine (5 residues) are N-terminal in R-phycocyanin (mol.wt. 273000). 3. Results suggest that the apoproteins of the various phycoerythrins are closely related, whereas C-phycocyanin has quite a different gross structure, and that R-phycocyanin contains two types of sub-unit, one related to C-phycocyanin and the other to the phycoerythrins.  相似文献   

6.
Glycoproteins are difficult to crystallize because they have heterogeneous glycans composed of multiple monosaccharides with considerable rotational freedom about their O-glycosidic linkages. Crystallographers studying N-glycoproteins often circumvent this problem by using β1,2-N-acetylglucosaminyltransferase I (MGAT1)–deficient mammalian cell lines, which produce recombinant glycoproteins with immature N-glycans. These glycans support protein folding and quality control but can be removed using endo-β-N-acetylglucosaminidase H (Endo H). Many crystallographers also use the baculovirus-insect cell system (BICS) to produce recombinant proteins for their work but have no access to an MGAT1-deficient insect cell line to facilitate glycoprotein crystallization in this system. Thus, we used BICS-specific CRISPR–Cas9 vectors to edit the Mgat1 gene of a rhabdovirus-negative Spodoptera frugiperda cell line (Sf-RVN) and isolated a subclone with multiple Mgat1 deletions, which we named Sf-RVNLec1. We found that Sf-RVN and Sf-RVNLec1 cells had identical growth properties and served equally well as hosts for baculovirus-mediated recombinant glycoprotein production. N-glycan profiling showed that a total endogenous glycoprotein fraction isolated from Sf-RVNLec1 cells had only immature and high mannose-type N-glycans. Finally, N-glycan profiling and endoglycosidase analyses showed that the vast majority of the N-glycans on three recombinant glycoproteins produced by Sf-RVNLec1 cells were Endo H-cleavable Man5GlcNAc2 structures. Thus, this study yielded a new insect cell line for the BICS that can be used to produce recombinant glycoproteins with Endo H-cleavable N-glycans. This will enable researchers to combine the high productivity of the BICS with the ability to deglycosylate recombinant glycoproteins, which will facilitate efforts to determine glycoprotein structures by X-ray crystallography.  相似文献   

7.
Sialic acids play an important role during development, regeneration and pathogenesis. The precursor of most physiological sialic acids, such as N-acetylneuraminic acid is N-acetyl-d-mannosamine. Application of the novel N-propanoylmannosamine leads to the incorporation of the new sialic acid N-propanoylneuraminic acid into cell surface glycoconjugates. Here we analyzed the modified sialylation of several organs with N-propanoylneuraminic acid in mice. By using peracetylated N-propanoylmannosamine, we were able to replace in vivo between 1% (brain) and 68% (heart) of physiological sialic acids by N-propanoylneuraminic acid. The possibility to modify cell surfaces with engineered sialic acids in vivo offers the opportunity to target therapeutic agents to sites of high sialic acid concentration in a variety of tumors. Furthermore, we demonstrated that application of N-propanoylmannosamine leads to a decrease in the polysialylation of the neural cell adhesion molecule in vivo, which is a marker of poor prognosis for some tumors with high metastatic potential.  相似文献   

8.
The rat serotonin transporter (rSERT) is an N-glycosylated integral membrane protein with 12 transmembrane regions; the N-glycans improve the ability of the SERT polypeptide chain to fold into a functional transporter, but they are not required for the transmembrane transport of serotonin per se. In order to define the best system for the expression, purification and structural analysis of serotonin transporter (SERT), we expressed SERT in Escherichia coli, Pichia pastoris, the baculovirus expression system and in four different stable mammalian cell lines. Two stable cell lines that constitutively expressed SERT (Imi270 and Coca270) were constructed using episomal plasmids in HEK293 cells expressing the EBNA-1 antigen. SERT expression in the three different inducible stable mammalian cell lines was induced either by a decrease in temperature (cell line pCytTS-SERT), the addition of tetracycline to the growth medium (cell line T-REx-SERT) or by adding DMSO which caused the cells to differentiate (cell line MEL-SERT). All the mammalian cell lines expressed functional SERT, but SERT expressed in E. coli or P. pastoris was nonfunctional as assessed by 5-hydroxytryptamine uptake and inhibitor binding assays. Expression of functional SERT in the mammalian cell lines was assessed by an inhibitor binding assay; the cell lines pCytTS-SERT, Imi270 and Coca270 contained levels of functional SERT similar to that of the standard baculovirus expression system (250,000 copies per cell). The expression of SERT in induced T-REx-SERT cells was 400,000 copies per cell, but in MEL-SERT it was only 80,000 copies per cell. All the mammalian stable cell lines expressed SERT at the plasma membrane as assessed by [3H]-5-hydroxytryptamine uptake into whole cells, but the Vmax for the T-Rex-SERT cell line was 10-fold higher than any of the other cell lines. It was noticeable that the cell lines that constitutively expressed SERT grew extremely poorly, compared to the inducible cell lines whose growth rates were similar to the parental cell lines when not induced. In addition, the cell lines MEL-SERT, Imi270 and T-REx-SERT all expressed fully N-glycosylated SERT and no unglycosylated inactive protein, in contrast to the baculovirus expression system where the vast majority of expressed SERT was unglycosylated and nonfunctional.  相似文献   

9.
Epidemiological studies corroborate a correlation between pesticide use and Parkinson's disease (PD). Thiocarbamate and dithiocarbamate pesticides are widely used and produce neurotoxicity in the peripheral nervous system. Recent evidence from rodent studies suggests that these compounds also cause dopaminergic (DAergic) dysfunction and altered protein processing, two hallmarks of PD. However, DAergic neurotoxicity has yet to be documented. We assessed DAergic dysfunction in Caenorhabditis elegans (C. elegans) to investigate the ability of thiocarbamate pesticides to induce DAergic neurodegeneration. Acute treatment with either S‐ethyl N,N‐dipropylthiocarbamate (EPTC), molinate, or a common reactive intermediate of dithiocarbamate and thiocarbamate metabolism, S‐methyl‐N,N‐diethylthiocarbamate (MeDETC), to gradual loss of DAergic cell morphology and structure over the course of 6 days in worms expressing green fluorescent protein (GFP) under a DAergic cell specific promoter. HPLC analysis revealed decreased DA content in the worms immediately following exposure to MeDETC, EPTC, and molinate. In addition, worms treated with the three test compounds showed a drastic loss of DAergic‐dependent behavior over a time course similar to changes in DAergic cell morphology. Alterations in the DAergic system were specific, as loss of cell structure and neurotransmitter content was not observed in cholinergic, glutamatergic, or GABAergic systems. Overall, our data suggest that thiocarbamate pesticides promote neurodegeneration and DAergic cell dysfunction in C. elegans, and may be an environmental risk factor for PD.  相似文献   

10.
The adhesiveness of cancerous cells to their neighboring cells significantly contributes to tumor progression and metastasis. The single-cell force spectroscopy (SCFS) approach was implemented to survey the cell–cell adhesion force between cancerous cells in three cancerous breast cell lines (MCF-7, T47D, and MDA-MB-231). The gene expression levels of two dominant cell adhesion markers (E-cadherin and N-cadherin) were quantified by real-time PCR. Additionally, the local stiffness of the cell bodies was measured by atomic force microscopy (AFM), and the actin cytoskeletal organization was examined by confocal microscopy. Results indicated that the adhesion force between cells was conversely correlated with their invasion potential. The highest adhesion force was observed in the MCF-7 cells. A reduction in cell–cell adhesion, which is required for the detachment of cells from the main tumor during metastasis, is partly due to the loss of E-cadherin expression and the enhanced expression of N-cadherins. The reduced adhesion was accompanied by the softening of cells, as described by the rearrangement of actin filaments through confocal microscopy observations. The softening of the cell body and the reduced cellular adhesiveness are two adaptive mechanisms through which malignant cells achieve the increased deformability, motility, and strong metastasis potential necessary for passage through endothelial junctions and positioning in host tissue. This study presented application of SCFS to survey cell phenotype transformation during cancer progression. The results can be implemented as a platform for further investigations that target the manipulation of cellular adhesiveness and stiffness as a therapeutic choice.  相似文献   

11.
We have generated a mouse monoclonal antibody (R-17F, IgG1 subtype) specific to human induced pluripotent stem (hiPS)/embryonic stem (ES) cells by using a hiPS cell line as an antigen. Triple-color confocal immunostaining images of hiPS cells with R-17F indicated that the R-17F epitope was expressed exclusively and intensively on the cell membranes of hiPS cells and co-localized partially with those of SSEA-4 and SSEA-3. Lines of evidence suggested that the predominant part of the R-17F epitope was a glycolipid. Upon TLC blot of total lipid extracts from hiPS cells with R-17F, one major R-17F-positive band was observed at a slow migration position close to that of anti-blood group H1(O) antigen. MALDI-TOF-MS and MSn analyses of the purified antigen indicated that the presumptive structure of the R-17F antigen was Fuc-Hex-HexNAc-Hex-Hex-Cer. Glycan microarray analysis involving 13 different synthetic oligosaccharides indicated that R-17F bound selectively to LNFP I (Fucα1–2Galβ1–3GlcNAcβ1–3Galβ1–4Glc). A critical role of the terminal Fucα1–2 residue was confirmed by the selective disappearance of R-17F binding to the purified antigen upon α1–2 fucosidase digestion. Most interestingly, R-17F, when added to hiPS/ES cell suspensions, exhibited potent dose-dependent cytotoxicity. The cytotoxic effect was augmented markedly upon the addition of the secondary antibody (goat anti-mouse IgG1 antibody). R-17F may be beneficial for safer regenerative medicine by eliminating residual undifferentiated hiPS cells in hiPS-derived regenerative tissues, which are considered to be a strong risk factor for carcinogenesis.  相似文献   

12.
The synthesis and characterization of a new water-soluble cytotoxic transplatinum compound are described. The new compounds, trans-[PtII(GC)2(NH3)2], is a transplatinum derivative containing an N2O2 donor set, using glycocholate (GC, a bile acid) ligands. The new compound has been characterized by infrared and NMR spectroscopies, as well as mass spectrometry. The FTIR spectra show a separation between νCOOas and νCOOs stretching bands in agreement with a monodentate binding mode of carboxylate group attached to platinum. The new compound is compared with cis-[PtIICl(GC)(NH3)2] in their cytotoxic properties against three cell lines (HELA229, A2780 and A2780cisR). Both compounds showed a poor inhibition on the growth of these cell lines in comparison with cis-platin (cis-DDP). Bile acids are involved in the enterohepatic cycle. This cycle can be useful for directing vectorially certain drugs for the treatment of diseases of the organs linked to this cycle. The next step of cytotoxicity assays will be performed in our laboratory, using cell lines related to these organs.  相似文献   

13.
《Process Biochemistry》2014,49(4):623-630
Herein, we report the effect of N,N-bis(dodecyloxycarbonylmethyl)-N,N,N,N-tetramethyl-1,2-ethanediammonium dibromide (dodecyl betainate gemini or DBG) on the structure and function of bovine serum albumin (BSA) by using fluorescence, time resolved fluorescence, circular dichroism and dynamic light scattering techniques. The Stern–Volmer quenching constants KSV and the corresponding thermodynamic parameters viz ΔH, ΔG and ΔS have been estimated by the fluorescence quenching method. The results indicated that DBG binds spontaneously with BSA through hydrophobic interaction. Time resolved fluorescence data show that the quenching follows the static mechanism pathway. It can be seen from far-UV CD spectra that the α-helical network of BSA is disrupted and its content increases from 71% to 79% at lower concentrations which again decreases to 38% at higher concentration. DLS measurements suggested that hydrodynamic radius (Rh) decreases in the presence of 30 and 40 μM of DBG while it increases when the concentration of DBG was 70 and 100 μM. The molecular docking study indicated that DBG is embedded into subdomain IIA of BSA and binds with the R-914, R-195 and R-217 residues by hydrogen bonding and by hydrophobic interaction.  相似文献   

14.
Two series of novel 4-chlorophenyl N-alkyl phosphoramidates of 3′-O-(t-butoxycarbonyl)-5-fluoro-2′-deoxyuridine (3′-BOC-FdU) (9a9j) and 5-fluoro-2′-deoxyuridine (FdU) (10a10j) were synthesized by means of phosphorylation of 3′-BOC-FdU (4) with 4-chlorophenyl phosphoroditriazolide (7), followed by a reaction with the appropriate amine. Phosphoramidates 9a9j were converted to the corresponding 10a10j by removal of the 3′-t-butoxycarbonyl protecting group (BOC) under acidic conditions. The synthesized phosphoramidates 9a9j and 10a10j were evaluated for their cytotoxic activity in five human cancer cell lines: cervical (HeLa), nasopharyngeal (KB), breast (MCF-7), liver (HepG2), osteosarcoma (143B) and normal human dermal fibroblast cell line (HDF) using the sulforhodamine B (SRB) assay. Two phosphoramidates 9b and 9j with the N-ethyl and N-(methoxy-(S)-alaninyl) substituents, respectively, displayed remarkable activity in all the investigated cancer cells, and the activity was considerably higher than that of the parent nucleoside 4 and FdU. Among phosphoramidates 10a10j compound 10c with the N-(2,2,2-trifluoroethyl) substituent showed the highest activity. Phosphoramidate 10c was more active than the FdU in all the cancer cell lines tested.  相似文献   

15.
To compare the sensitivity of different mammalian cell types towards the cytotoxic action of nitric oxide, freshly isolated rat pancreatic islet cells, hepatocytes, resident and activated macrophages, cultured aortic endothelial cells and two murine tumor cell lines were tested for susceptibility towards exogenous nitric oxide. As sources for nitric oxide nitroprusside, S-nitroso-N-acetyl-penicillamine and the sydnonimine-derivative SIN-1 were used. These generate nitric oxide by different mechanisms and kinetics. Among the cell types tested we found large differences in their susceptibility towards the three nitric oxide donors. Islet cells were by far the most sensitive of the investigated cells and were completely lysed by all three nitric oxide donors. Hepatocytes and endothelial cells were sensitive towards nitroprusside but relatively resistant towards toxicity of SIN-1 and S-nitroso-N-acetyl-penicillamine. Activated and resident macrophages were lysed by SIN-1, whereas high concentrations of nitroprusside and S-nitroso-N-acetyl-penicillamine led to partial cell lysis only. The tumor cell lines were both lysed by SIN-1 but showed differences in their sensitivity towards S-nitroso-N-acetyl-penicillamine. Nitric oxide, which is produced in large amounts during infection and inflammation, may play an important role in the destruction of islet cells during insulitis leading to insulin-dependent diabetes mellitus.  相似文献   

16.
Summary A cell cycle analysis of theTrichoplusia ni (TN-368) insect cell line is described. By means of autoradiography and percent labeled metaphase data, the cell cycle parameters were determined to be as follows: S, 4.5 hr; G2, 8.5 hr; M, 0.5 hr; G1, 1.0 hr; the total cell time being 14.5 hr. A synchronization procedure using 50mm thymidine in a double block procedure was used to provide a method of obtaining a large number of cells in particular cell cycle phases, especially S and G2. This work was supported in part by U.S. Environmental Protection Agency Grant R-802516.  相似文献   

17.
18.
Three dimensional cell cultures are attractive models for biological research. They combine the flexibility and cost-effectiveness of cell culture with some of the spatial and molecular complexity of tissue. For example, many cell lines form 3D structures given appropriate in vitro conditions. Colon cancer cell lines form 3D cell culture spheroids, in vitro mimics of avascular tumor nodules. While immunohistochemistry and other classical imaging methods are popular for monitoring the distribution of specific analytes, mass spectrometric imaging examines the distribution of classes of molecules in an unbiased fashion. While MALDI mass spectrometric imaging was originally developed to interrogate samples obtained from humans or animal models, this report describes the analysis of in vitro three dimensional cell cultures, including improvements in sample preparation strategies. Herein is described methods for growth, harvesting, sectioning, washing, and analysis of 3D cell cultures via matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) imaging. Using colon carcinoma 3D cell cultures as a model system, this protocol demonstrates the ability to monitor analytes in an unbiased fashion across the 3D cell culture system with MALDI-MSI.  相似文献   

19.

Background

The present study investigates the effects of high external calcium concentration ([Ca2+]o) and the calcimimetic NPS R-467, a known calcium-sensing receptor (CaSR) agonist, on growth/proliferation of two equine size-sieved umbilical cord matrix mesenchymal stem cell (eUCM-MSC) lines. The involvement of CaSR on observed cell response was analyzed at both the mRNA and protein level.

Methodology/Principal Findings

A large (>8 µm in diameter) and a small (<8 µm) cell line were cultured in medium containing: 1) low [Ca2+]o (0.37 mM); 2) high [Ca2+]o (2.87 mM); 3) NPS R-467 (3 µM) in presence of high [Ca2+]o and 4) the CaSR antagonist NPS 2390 (10 µM for 30 min.) followed by incubation in presence of NPS R-467 in medium with high [Ca2+]o. Growth/proliferation rates were compared between groups. In large cells, the addition of NPS R-467 significantly increased cell growth whereas increasing [Ca2+]o was not effective in this cell line. In small cells, both higher [Ca2+]o and NPS R-467 increased cell growth. In both cell lines, preincubation with the CaSR antagonist NPS 2390 significantly inhibited the agonistic effect of NPS R-467. In both cell lines, increased [Ca2+]o and/or NPS R-467 reduced doubling time values.Treatment with NPS R-467 down-regulated CaSR mRNA expression in both cell lines. In large cells, NPS R-467 reduced CaSR labeling in the cytosol and increased it at cortical level.

Conclusions/Significance

In conclusion, calcium and the calcimimetic NPS R-467 reduce CaSR mRNA expression and stimulate cell growth/proliferation in eUCM-MSC. Their use as components of media for eUCM-MSC culture could be beneficial to obtain enough cells for down-stream purposes.  相似文献   

20.
A series of sixteen β-carbolines, bearing chalcone moiety at C-1 position, were prepared from easily accessible 1-acetyl-β-carboline and various aldehydes under basic conditions followed by N2-alkylation using different alkyl bromides. The prepared compounds were evaluated for in vitro cytotoxicity against a panel of human tumor cell lines. N2-Alkylated-β-carboline chalcones 13a-i represented the interesting anticancer activities compared to N2-unsubstituted β-carboline chalcones 12a-g. Off the prepared β-carbolines, 13g exhibited broad spectrum of activity with IC50 values lower than 22.5?µM against all the tested cancer cell lines. Further, the N2-alkylated-β-carboline chalcone 13g markedly induced cell death in MDA-MB-231 cells by AO/EB staining assay. The most cytotoxic compound 13g possessed a relatively high drug score of 0.48. Additionally, the prepared β-carboline chalcones displayed moderate antibacterial activities against tested bacterial strains.  相似文献   

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