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1.
A new Cu(II) complex of CuLCl(2) (here, L=N(1),N(8)-bis(1-methyl-4-nitropyrrole-2- carbonyl)triethylenetetramine) had been synthesized and characterized. The structure of the complex was investigated with density functional theory (DFT) calculations. DNA-binding of the Cu(II) complex and its effects on tumor cell viability were firstly studied. The interactions between the complex and calf thymus DNA had been investigated using UV spectra, fluorescent spectra, viscosity and CV (cyclic voltammetry). The cleavage reaction on plasmid DNA has been monitored by agarose gel electrophoresis. The experimental results show that the mode of binding of the complex to DNA is classical intercalation and the complex can cleave pBR322 DNA. The effects of the CuL on cell viability were tested using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide) dye assay and the results indicate that the CuL had certain effect on cancer cells. 相似文献
2.
Glutamine-free culture of Vero cells has previously been shown to cause higher cell yield and lower ammonia accumulation than
that in glutamine-containing culture. Nitrogen metabolism of asparagine and glutamate as glutamine replacer was studied here
using nuclear magnetic resonance (NMR) spectroscopy. 15N-labelled glutamate or asparagine was added and their incorporation into nitrogenous metabolites was monitored by heteronuclear
multiple bond coherence (HMBC) NMR spectroscopy. In cells incubated with l-[15N]glutamate, the 15N label was subsequently found in a number of metabolites including alanine, aspartate, proline, and an unidentified compound.
No detectable signal occurred, indicating that glutamate was utilized by transamination rather than by oxidative deamination. In cells
incubated with l-[2-15N]asparagine, the 15N label was subsequently found in aspartate, the amine group of glutamate/glutamine, and in two unidentified compounds. Incubation
of cells with l-[4-15N]asparagine showed that the amide nitrogen of asparagine was predominantly transferred to glutamine amide. There was no detectable
production of , showing that most of the asparagine amide was transaminated by asparagine synthetase rather than deaminated by asparaginase.
Comparing with a glutamine-containing culture, the activities of phosphate-activated glutaminase (PAG), glutamate dehydrogenase
(GDH) and alanine aminotransferase (ALT) decreased significantly and the activity of aspartate aminotransferase (AST) decreased
slightly. 相似文献
3.
Significant resolution improvement in 13C,13C-TOCSY spectra of uniformly deuterated and 13C, 15N-labeled protein and 13C,15N-labeled RNA samples is achieved by introduction of multiple-band-selective 13C-homodecoupling applied simultaneously with 1H- or 2H- and 15N-decoupling at all stages of multidimensional experiments including signal acquisition period. The application of single, double or triple band-selective 13C-decoupling in 2D-[13C,13C]-TOCSY experiments during acquisition strongly simplifies the homonuclear splitting pattern. The technical aspects of complex multiple-band homonuclear decoupling and hardware requirements are discussed. The use of this technique (i) facilitates the resonance assignment process as it reduces signal overlap in homonuclear 13C-spectra and (ii) possibly improves the signal-to-noise ratio through multiplet collapse. It can be applied in any 13C-detected experiment. 相似文献
4.
Paramagnetic metal ions in proteins provide a rich source of structural information, but the resonance assignments required
to extract the information can be challenging. Here we demonstrate that paramagnetically shifted 15N-HSQC cross-peaks can be assigned using NZ-exchange spectroscopy under conditions in which the paramagnetic form of the protein is in dynamic equilibrium with its diamagnetic
form. Even slow exchange of specifically bound metal ions may be detected within the long lifetime of 15N longitudinal magnetization of large proteins at high magnetic fields. Alternatively, the exchange can be accelerated using
an excess of metal ions. In the resulting exchange spectra, paramagnetic 15N resonances become visible for residues that are not directly observed in a conventional 15N-HSQC spectrum due to paramagnetic 1HN broadening. The experiments are illustrated by the 30 kDa lanthanide-binding ɛ186/θ complex of DNA polymerase III in the
presence of sub-stoichiometric amounts of Dy3+ or a mixture of Dy3+ and La3+. 相似文献
5.
T. N. Kolokolova N. M. Sergeev A. Yu. Korol’kov 《Biochemistry (Moscow) Supplemental Series B: Biomedical Chemistry》2008,2(4):418-425
Conditions for registration of urinary 1H NMR spectra have been optimized in order to achieve maximal accuracy of quantitative analysis. Urinary samples from patients with acute pancreatitis have been investigated and spectral data of identified urinary metabolites and results of their quantitative determination are given. Employment of 1H NMR spectra is perspective for the development of new laboratory diagnostic methods. 相似文献
6.
The complexes [Fe(Sal2trien)]NO3 and Cu(Sal2trien) have been synthesized and their interaction with calf thymus DNA has been investigated for the first time using UV spectra, fluorescence spectra, thermal denaturation, and viscosity measurements. The experimental results show conformably that the mode of binding of the complex [Fe(Sal2trien)]NO3 to DNA is nonclassical electrostatic action, but the mode of binding of the complex Cu(Sal2trien) to DNA is classical intercalation. 相似文献
7.
Although arsenic is an infamous carcinogen, it has been effectively used to treat acute promyelocytic leukemia, and can induce
cell cycle arrest or apoptosis in human solid tumors. Previously, we had demonstrated that opposing effects of ERK1/2 and
JNK on p21 expression in response to arsenic trioxide (As2O3) are mediated through the Sp1 responsive elements of the p21 promoter in A431 cells. Presently, we demonstrate that Sp1,
and c-Jun functionally cooperate to activate p21 promoter expression through Sp1 binding sites (−84/−64) by using DNA affinity
binding, chromatin immunoprecipitation, and promoter assays. Surprisingly, As2O3-induced c-Jun(Ser63/73) phosphorylation can recruit TGIF/HDAC1 to the Sp1 binding sites and then suppress p21 promoter activation.
We suggest that, after As2O3 treatment, the N-terminal domain of c-Jun phosphorylation by JNK recruits TGIF/HDAC1 to the Sp1 sites and then represses p21
expression. That is, TGIF is involved in As2O3-inhibited p21 expression, and then blocks the cell cycle arrest. 相似文献
8.
Tomasz Laskowski Jacek Czub Paweł Sowiński Jan Mazerski 《Journal of biomolecular structure & dynamics》2016,34(3):653-663
Imidazoacridinone C-1311 (Symadex®) is a powerful antitumor agent, which successfully made its way through the Phase I clinical trials and has been recommended for Phase II few a years ago. It has been shown experimentally that during the initial stage of its action C-1311 forms a relatively stable intercalation complex with DNA, yet it has shown no base-sequence specificity while binding to DNA. In this paper, the d(CGATCG)2:C-1311 intercalation complex has been studied by means of two-dimensional NMR spectroscopy, yielding a full assignment of the resonance lines observed in 1H NMR spectra. The observation of the intermolecular NOE contacts between C-1311 and DNA allowed locating the ligand between the guanine and adenine moieties. Formation of a symmetric complex was pointed out on the basis of the lack of a second set of the 1H resonances. The resulting stereostructure of the complex was then improved by means of molecular dynamics, using the CHARMM force field and GROMACS software. To this end, distance restraints derived from the NOESY cross-peak volumes were applied to the atomistic model of the d(CGATCG)2:C-1311 complex. Obtained results are in full agreement with biochemical data on the mechanism of action of C-1311, in particular with the previously postulated post-intercalation enzymatic activation of the studied drug. 相似文献
9.
An efficient and simple one-pot synthesis of a new 1,2,3-triazole-1-oxide via reaction between isonitrosoacetophenone hydrazone and dipyridyl ketone in the EtOH/AcOH at room temperature has been developed smoothly in high yield. The reaction proceeds via metal salt free, in-situ formation of asymmetric azine followed by cyclization to provide 1,2,3-triazole 1-oxide compound. It has been structurally characterized. The 1:1 ratio reaction of the 1,2,3-triazole 1-oxide ligand with nickel(II) chloride gives the mononuclear complex [Ni(L)(DMF)Cl2], hexa-coordinated within an octahedral geometry. Characterization of the 1,2,3-triazole compound and its Ni(II) complex with FTIR, 1H and 13C NMR, UV–vis and elemental analysis also confirms the proposed structures of the compounds. The interactions of the compounds with Calf thymus DNA (CT-DNA) have been investigated by UV–visible spectra and viscosity measurements. The results suggested that both ligand and Ni(II) complex bind to DNA in electrostatic interaction and/or groove binding, also with a slight partial intercalation in the case of ligand. DNA cleavage experiments have been also investigated by agarose gel electrophoresis in the presence and absence of an oxidative agent (H2O2). Both 1,2,3-triazole 1-oxide ligand and its nickel(II) complex show nuclease activity in the presence of hydrogen peroxide. DNA binding and cleavage affinities of the 1,2,3-triazole 1-oxide ligand is stronger than that of the Ni(II) complex. 相似文献
10.
Global analysis of 1H-NMR spectra of serum is an appealing approach for the rapid detection of cancer. To evaluate the usefulness of this method
in distinguishing between mammary tumor-bearing mice and healthy controls, we conducted 1H-NMR metabonomic analyses on serum samples obtained from the following: 10 mice inoculated with a highly-metastatic mammary
carcinoma cell line, 10 mice inoculated with a “normally” metastatic mammary carcinoma cell line, and 10 healthy controls.
Following standard spectral processing and subsequent data reduction, we applied unsupervised Principal Component Analysis
(PCA) to determine if unique metabolic fingerprints for different categories of metastatic breast cancer in serum exist. The
PCA method correctly separated sera of tumor-bearing mice from that of normal healthy controls, as shown using the scores
plot which indicated that sera classes from tumor-bearing mice did not share multivariate space with that from healthy controls.
In addition, this technique was capable of distinguishing between classes of varying metastatic ability in this system. Metabolites
apparently responsible for separation between diseased and healthy mice include lactate, taurine, choline, and sugar moieties.
Results of this study suggest that 1H-NMR spectra of mouse serum analyzed using PCA statistical methods indicate separation of tumor-bearing mice from healthy
normal controls, justifying further study of the use of 1H-NMR metabonomics for cancer detection using serum. 相似文献
11.
The effect of ANG II on pHi, [Ca2+]i and cell volume was investigated in T84 cells, a cell line originated from colon epithelium, using the probes BCECF-AM, Fluo
4-AM and acridine orange, respectively. The recovery rate of pHi via the Na+/H+ exchanger was examined in the first 2 min following the acidification of pHi with a NH4Cl pulse. In the control situation, the pHi recovery rate was 0.118 ± 0.001 (n = 52) pH units/min and ANG II (10−12 M or 10−9 M) increased this value (by 106% or 32%, respectively) but ANG II (10−7 M) decreased it to 47%. The control [Ca2+]i was 99 ± 4 (n = 45) nM and ANG II increased this value in a dose-dependent manner. The ANG II effects on cell volume were minor and late
and should not interfere in the measurements of pHi recovery and [Ca2+]i. To document the signaling pathways in the hormonal effects we used: Staurosporine (a PKC inhibitor), W13 (a calcium-dependent
calmodulin antagonist), H89 (a PKA inhibitor) or Econazole (an inhibitor of cytochrome P450 epoxygenase). Our results indicate
that the biphasic effect of ANG II on Na+/H+ exchanger is a cAMP-independent mechanism and is the result of: 1) stimulation of the exchanger by PKC signaling pathway
activation (at 10−12 – 10−7 M ANG II) and by increases of [Ca2+]i in the lower range (at 10−12 M ANG II) and 2) inhibition of the exchanger at high [Ca2+]i levels (at 10−9 – 10−7 M ANG II) through cytochrome P450 epoxygenase-dependent metabolites of the arachidonic acid signaling pathway. 相似文献
12.
Tian JL Feng L Gu W Xu GJ Yan SP Liao DZ Jiang ZH Cheng P 《Journal of inorganic biochemistry》2007,101(2):196-202
One new binuclear Co(II) complex of N,N,N',N'-tetrakis(2-benzimidazolylmethyl)-2-hydroxyl-1,3-diaminopropane (HL), [Co(2)L(mu(2)-Cl)](ClO(4))(2) x 3CH(3)CN x C(2)H(5)OC(2)H(5) (1), has been synthesized and its crystal structure and magnetic properties are shown. In 1, each Co(II) atom has a distorted trigonal bipyramidal geometry with a N(3)OCl donor set. The central two Co(II) atoms are bridged by one alkoxo-O atom and one Cl atom with the Co1-Co2 separation of 3.239 A. Susceptibility data of 1 indicate strong intramolecular antiferromagnetic coupling of the high-spin Co(II) atoms. In this paper, the interaction with calf thymus DNA was investigated by UV absorption and fluorescent spectroscopy. Results show the complex binds to ct-DNA with a intercalative mode. The interaction between complex 1 and pBR322 DNA has also been investigated by submarine gel electrophoresis, noticeably, the complex exhibits effective DNA cleavage activity in the absence of any external agents. 相似文献
13.
Animals with high metabolic rates are believed to have high rates of carbon and nitrogen isotopic incorporation. We hypothesized
that (1) chronic exposure to cold, and hence an increase in metabolic rate, would increase the rate of isotopic incorporation
of both 13C and 15N into red blood cells; and (2) that the rate of isotopic incorporation into red blood cells would be allometrically related
to body mass. Two groups of sparrows were chronically exposed to either 5 or 22°C and switched from a 13C-depleted C3-plant diet to a more 13C-enriched C4-plant one. We used respirometry to estimate the resting metabolic rate of birds exposed chronically to our two experimental temperatures. The allometric relationship between the rate of 13C incorporation into blood and body mass was determined from published data. The of birds at 5°C was 1.9 times higher than that of birds at 22°C. Chronic exposure to a low temperature did not have an effect
on the rate of isotopic incorporation of 15N save for a very small effect on the incorporation of 13C. The isotopic incorporation rate of 13C was 1.5 times faster than that of 15N. The fractional rate of 13C incorporation into avian blood was allometrically related to body mass with an exponent similar to −1/4. We conclude that
the relationship between metabolic rate and the rate of isotopic incorporation into an animal’s tissues is indirect. It is
probably mediated by protein turnover and thus more complex than previous studies have assumed. 相似文献
14.
J. W. Mietelski M. A. Olech K. Sobiech-Matura B. J. Howard P. Gaca M. Zwolak S. Błażej E. Tomankiewicz 《Polar Biology》2008,31(9):1081-1089
There are few data reported on radionuclide contamination in Antarctica. The aim of this paper is to report 137Cs, 90Sr and 238,239+240Pu and 40K activity concentrations measured in biological samples collected from King George Island (Southern Shetlands, Antarctica),
mostly during 2001–2002. The samples included: bones, eggshells and feathers of penguin Pygoscelis papua, bones and feathers of petrel Daption capense, bones and fur of seal Mirounga leonina, algae Himantothallus grandifolius, Desmarestia anceps and Cystosphaera jacquinotii, fish Notothenia corriceps, sea invertebrates Amphipoda, shells of limpet Nacella concina, lichen Usnea aurantiaco-atra, vascular plants Deschampsia antarctica and Colobanthus quitensis, fungi Omphalina pyxidata, moss Sanionia uncinata and soil. The results show a large variation in some activity concentrations. Samples from the marine environment had lower
contamination levels than those from terrestrial ecosystems. The highest activity concentrations for all radionuclides were
found in lichen and, to a lesser extent, in mosses, probably because lichens take up atmospheric pollutants and retain them.
The only significant correlation (except for that expected between 238Pu and 239+240Pu) was noted for moss and lichen samples between plutonium and 90Sr. A tendency to a slow decrease with time seems to be occurring. Analyses of the activity ratios show varying fractionation
between various radionuclides in different organisms. Algae were relatively more highly contaminated with plutonium and radiostrontium,
and depleted with radiocesium. Feathers had the lowest plutonium concentrations. Radiostrontium and, to a lesser extent, Pu
accumulated in bones. The present low intensity of fallout in Antarctic has a lower 238Pu/239+240Pu activity ratio than that expected for global fallout. 相似文献
15.
16.
Nutrient uptake by forest trees is dependent on ectomycorrhizal (EM) mycelia that grow out into the soil from the mycorrhizal root tips. We estimated the production of EM mycelia in root free samples of pure spruce and mixed spruce-oak stands in southern Sweden as mycelia grown into sand-filled mesh bags placed at three different soil depths (0–10, 10–20 and 20–30 cm). The mesh bags were collected after 12 months and we found that 590±70 kg ha–1 year–1 of pure mycelia was produced in spruce stands and 420±160 kg ha–1 year–1 in mixed stands. The production of EM mycelia in the mesh bags decreased with soil depth in both stand types but tended to be more concentrated in the top soil in the mixed stands compared to the spruce stands. The fungal biomass was also determined in soil samples taken from different depths by using phospholipid fatty acids as markers for fungal biomass. Subsamples were incubated at 20°C for 5 months and the amount of fungal biomass that degraded during the incubation period was used as an estimate of EM fungal biomass. The EM biomass in the soil profile decreased with soil depth and did not differ significantly between the two stand types. The total EM biomass in the pure spruce stands was estimated to be 4.8±0.9×103 kg ha–1 and in the mixed stands 5.8±1.1×103 kg ha–1 down to 70 cm depth. The biomass and production estimates of EM mycelia suggest a very long turnover time or that necromass has been included in the biomass estimates. The amount of N present in EM mycelia was estimated to be 121 kg N ha–1 in spruce stands and 187 kg N ha–1 in mixed stands. The 13C value for mycelia in mesh bags was not influenced by soil depth, indicating that the fungi obtained all their carbon from the tree roots. The 13C values in mycelia collected from mixed stands were intermediate to values from pure spruce and pure oak stands suggesting that the EM mycelia received carbon from both spruce and oak trees in the mixed stands. The 15N value for the EM mycelia and the surrounding soil increased with soil depth suggesting that they obtained their entire N from the surrounding soil. 相似文献
17.
Kashanian S Shahabadi N Roshanfekr H Shalmashi K Omidfar K 《Biochemistry. Biokhimii?a》2008,73(8):929-936
The interaction of native calf thymus DNA with the Pd(II) complex, PdCl2(LL) (LL = chelating diamine ligand: N,N-dimethyltrimethylenediamine), in 10 mM Hepes aqueous solutions at neutral pH has been monitored as a function of metal complex/DNA molar ratio by UV absorption spectrophotometry, circular dichroism (CD), viscosimetry, and fluorescence spectroscopy. The results support two modes of interaction. In particular, this complex showed absorption hypochromism and then hyperchromism, increase in melting temperature, and some structural changes in specific viscosity when bound to calf thymus DNA. The binding constant determined using absorption measurement is 2.69.10(3) M(-1). As evidenced by the increasing fluorescence of methylene blue-DNA solutions in the presence of increasing amounts of metal complex, PdCl(2)(LL) is able to displace the methylene blue intercalated into DNA, but not so completely, as indicated by partial intercalation. CD spectral changes in two steps and viscosity decrease confirm our conclusions. 相似文献
18.
To compare the cytotoxicities and the DNA-binding properties in tetranuclear complexes with different bridging ligands, two tetracopper(II) complexes with formulae of [Cu4(oxbe)2Cl2(bpy)2]·4H2O (1) and [Cu4(oxbm)2Cl2(bpy)2]·2H2O (2) were synthesized, where H3oxbe and H3oxbm stand for N-benzoato-N′-(2-aminoethyl)oxamide and N-benzoato-N′-(1,2-propanediamine)oxamide, respectively, and bpy is 2,2′-bipyridine. Complex 1 was characterized by elemental analyses, IR and electronic spectra and single-crystal X-ray diffraction. The crystal structure reveals the presence of the circular tetranuclear copper(II) cations which are assembled by a pair of cis-oxamido-bridged dinuclear copper(II) units through carboxyl bridges. The crystal structure of complex 2 has been reported in our previous paper. However, the bioactivities were not studied. Cytotoxicities experiments reveal that both the two complexes exhibit cytotoxic effects against human hepatocellular carcinoma cell SMMC-7721 and human lung adenocarcinoma cell A549, and complex 1 has the better activities than those of complex 2. The results of the interactions between the two complexes and herring sperm DNA (HS-DNA) suggest that the two complexes interact with HS-DNA in the mode of intercalation with the intrinsic binding constants of 3.93 × 104 M−1 (1) and 2.48 × 104 M−1 (2). These results indicated that the bridging ligands may play an important role in the cytotoxicities and the DNA-binding properties of tetranuclear complexes. 相似文献
19.
Hui Chen Rui An Jiang-Hua Tang Xiang-Huan Cui Fu-Shun Hao Jia Chen Xue-Chen Wang 《Molecular breeding : new strategies in plant improvement》2007,19(3):215-225
To develop a salt-tolerant upland rice cultivar (Oryza sativa L.), OsNHX1, a vacuolar-type Na+/H+ antiporter gene from rice was transferred into the genome of an upland rice cultivar (IRAT109), using an Agrobacterium-mediated method. Seven independent transgenic calli lines were identified by polymerase chain reaction (PCR) analysis. These
35S::OsNHX1 transgenic plants displayed a little accelerated growth during seedling stage but showed delayed flowering time and a slight
growth retardation phenotype during late vegetative stage, suggesting that the OsNHX1 has a novel function in plant development. Northern and western blot analyses showed that the expression levels of OsNHX1 mRNA and protein in the leaves of three independent transgenic plant lines were significantly higher than in the leaves of
wild type (WT) plants. T2 generation plants exhibited increased salt tolerance, showing delayed appearance and development of damage or death caused
by salt stress, as well as improved recovery upon removal from this condition. Several physiological traits, such as increased
Na+ content, and decreased osmotic potential in transgenic plants grown in high saline concentrations, further indicated that
the transgenic plants had enhanced salt tolerance. Our results suggest the potential use of these transgenic plants for further
agricultural applications in saline soil. 相似文献
20.
Carbonyl 13C′ relaxation is dominated by the contribution from the 13C′ chemical shift anisotropy (CSA). The relaxation rates provide useful and non-redundant structural information in addition
to dynamic parameters. It is straightforward to acquire, and offers complimentary structural information to the 15N relaxation data. Furthermore, the non-axial nature of the 13C′ CSA tensor results in a T1/T2 value that depends on an additional angular variable even when the diffusion tensor of the protein molecule is axially symmetric.
This dependence on an extra degree of freedom provides new geometrical information that is not available from the NH dipolar
relaxation. A protocol that incorporates such structural restraints into NMR structure calculation was developed within the
program Xplor-NIH. Its application was illustrated with the yeast Fis1 NMR structure. Refinement against the 13C′ T1/T2 improved the overall quality of the structure, as evaluated by cross-validation against the residual dipolar coupling as
well as the 15N relaxation data. In addition, possible variations of the CSA tensor were addressed.
Electronic Supplementary Material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献