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101.
102.
Breast cancer cell cultures were exposed to different concentrations of black cohosh, estradiol (E2), and tamoxifen to examine the effect on cell proliferation; cytotoxicity was assessed by using sulforhodamine B (SRB) dye solution. E2 (10(-10) - 10(-8) mol/L) markedly stimulated the proliferation of MCF-7 cells (p < 0.01). Tamoxifen stimulated MCF-7 cell proliferation at 10(-6) mol/L and 10(-5) mol/L (p < 0.005) but inhibited in a dose-dependent fashion the proliferative effect of E2 (p < 0.001). Black cohosh alone did not show any stimulatory effect, but exhibited a cytotoxic effect, which was significant at 10(3) microg/mL (p < 0.001). Adding black cohosh at 10(0)-10(3) microg/mL to E2 at 10(-9) mol/L also resulted in a dose-dependent inhibition of E2 proliferative effect. Interestingly, the combination of black cohosh (10(0)-10(3) microg/mL) with increasing tamoxifen concentrations further inhibited MCF-7 cell growth. On MDA-MB-231 cells, neither E2 nor tamoxifen displayed any detectable effect. However, black cohosh inhibited MDA-MB-231 cell proliferation at 10(3) microg/mL (p < 0.05), and this inhibitory effect was enhanced by increasing tamoxifen concentrations. This study reveals a cytotoxic effect of black cohosh on both estrogen-sensitive and estrogen-insensitive breast cancer cells and a synergism with tamoxifen for inhibition of cancerous cell growth. 相似文献
103.
Valérie Capelle Carine Remoué Laurence Moreau Agnès Reyss Aline Mahé Agnès Massonneau Matthieu Falque Alain Charcosset Claudine Thévenot Peter Rogowsky Sylvie Coursol Jean-Louis Prioul 《BMC plant biology》2010,10(1):1-22
Background
Kernel moisture at harvest is an important trait since a low value is required to prevent unexpected early germination and ensure seed preservation. It is also well known that early germination occurs in viviparous mutants, which are impaired in abscisic acid (ABA) biosynthesis. To provide some insight into the genetic determinism of kernel desiccation in maize, quantitative trait loci (QTLs) were detected for traits related to kernel moisture and ABA content in both embryo and endosperm during kernel desiccation. In parallel, the expression and mapping of genes involved in kernel desiccation and ABA biosynthesis, were examined to detect candidate genes.Results
The use of an intermated recombinant inbred line population allowed for precise QTL mapping. For 29 traits examined in an unreplicated time course trial of days after pollination, a total of 78 QTLs were detected, 43 being related to kernel desiccation, 15 to kernel weight and 20 to ABA content. Multi QTL models explained 35 to 50% of the phenotypic variation for traits related to water status, indicating a large genetic control amenable to breeding. Ten of the 20 loci controlling ABA content colocated with previously detected QTLs controlling water status and ABA content in water stressed leaves. Mapping of candidate genes associated with kernel desiccation and ABA biosynthesis revealed several colocations between genes with putative functions and QTLs. Parallel investigation via RT-PCR experiments showed that the expression patterns of the ABA-responsive Rab17 and Rab28 genes as well as the late embryogenesis abundant Emb5 and aquaporin genes were related to desiccation rate and parental allele effect. Database searches led to the identification and mapping of two zeaxanthin epoxidase (ZEP) and five novel 9-cis-epoxycarotenoid dioxygenase (NCED) related genes, both gene families being involved in ABA biosynthesis. The expression of these genes appeared independent in the embryo and endosperm and not correlated with ABA content in either tissue.Conclusions
A high resolution QTL map for kernel desiccation and ABA content in embryo and endosperm showed several precise colocations between desiccation and ABA traits. Five new members of the maize NCED gene family and another maize ZEP gene were identified and mapped. Among all the identified candidates, aquaporins and members of the Responsive to ABA gene family appeared better candidates than NCEDs and ZEPs. 相似文献104.
Bennasroune A Fickova M Gardin A Dirrig-Grosch S Aunis D Crémel G Hubert P 《Molecular biology of the cell》2004,15(7):3464-3474
Receptor tyrosine kinases have a single transmembrane (TM) segment that is usually assumed to play a passive role in ligand-induced dimerization and activation of the receptor. However, mutations within some of these receptors, and recent studies with the epidermal growth factor (EGF) and ErbB2 receptors have indicated that interactions between TM domains do contribute to stabilization of ligand-independent and/or ligand-induced receptor dimerization and activation. One consequence of the importance of these interactions is that short hydrophobic peptides corresponding to these domains should act as specific inhibitors. To test this hypothesis, we constructed expression vectors encoding short fusion peptides encompassing native or mutated TM domains of the EGF, ErbB2, and insulin receptors. In human cell lines overexpressing the wild-type EGF receptor or ErbB2, we observed that the peptides are expressed at the cell surface and that they inhibit specifically the autophosphorylation and signaling pathway of their cognate receptor. Identical results were obtained with peptides chemically synthesized. Mechanism of action involves inhibition of dimerization of the receptors as shown by the lack of effects of mutant nondimerizing sequences, completed by density centrifugation and covalent cross-linking experiments. Our findings stress the role of TM domain interactions in ErbB receptor function, and possibly for other single-spanning membrane proteins. 相似文献
105.
Estelle Dumont Véronique Fontaine Christophe Vuylsteker Hélène Sellier Sylvie Bodèle Najia Voedts Rosemonde Devaux Marlène Frise Komlan Avia Jean-Louis Hilbert Nasser Bahrman Eric Hanocq Isabelle Lejeune-Hénaut Bruno Delbreil 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2009,118(8):1561-1571
To increase yield in pea (Pisum sativum L.), autumn sowing would be preferable. Hence, frost tolerance of pea became a major trait of interest for breeders. In order
to better understand the cold acclimation in pea, Champagne a frost tolerant line and Terese, a frost sensitive line, and
their recombinant inbred lines (RIL) were studied. RIL frost tolerance was evaluated by a frost damage scale under field as
well as controlled conditions. A quantitative trait loci (QTL) approach was used to identify chromosomal regions linked to
frost tolerance. The detected QTL explained from 6.5 to 46.5% of the phenotypic variance. Amongst them, those located on linkage
groups 5 and 6 were consistent with over all experiments, in field as well as in controlled environments. In order to improve
the understanding of the frost tolerance mechanisms, several cold acclimation key characters such as concentration of sugars,
electrolyte leakage, osmotic pressure, and activity of RuBisCO were assessed. Some of these physiological QTL colocalised
with QTL for frost damage, in particular two raffinose QTL on LG5 and LG6 and one RuBisCO activity QTL on LG6, explaining
8.8 to 27.0% of the phenotypic variance. In addition, protein quantitative loci were mapped; some of them colocalised with
frost damage and physiological QTL on LG5 and LG6, explaining 16.0–43.6% of the phenotypic variance. Raffinose metabolism
and RuBisCO activity and its effect on photosynthesis might play a major role in cold acclimation of pea.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
106.
Prado S Michel S Tillequin F Koch M Pfeiffer B Pierré A Léonce S Colson P Baldeyrou B Lansiaux A Bailly C 《Bioorganic & medicinal chemistry》2004,12(14):3943-3953
Fagaronine and nitidine are natural benzo[c] phenanthridinium alkaloids, which display antileukemic activity. Both act as topoisomerase I and topoisomerase II inhibitors. The objective of the present study was to prepare noncharged isosters of these compounds, with replacement of the aromatic A ring by a pyridine ring, present in other topoisomerase I inhibitors. Various 7,8- and 8,9-dimethoxy and metylenedioxy benzo[c][1,7] and [1,8]phenanthrolines were readily synthesized by benzyne-mediated cyclization of the corresponding substituted N-(2-halobenzyl)-5-quinolinamines or 5-isoquinolinamines. In both series, compounds bearing oxygenated substituents at positions 8 and 9 exhibited cytotoxic properties towards L1210 murine leukemia cells, which may result from their capacities to intercalate into DNA. Topoisomerase I inhibition was observed for all active compounds. 相似文献
107.
Sophie Lepage Bernard Lakaye Moreno Galleni Iris Thamm Michel Crine Sylvie Groslambert Jean-Marie Frère 《Molecular microbiology》1995,16(2):365-372
With the help of a new highly sensitive method allowing the quantification of free penicillin-binding proteins (PBPs) and of an integrated mathematical model, the progressive saturation of PBP1 by various β-lactam antibiotics in growing cells of Bacillus licheniformis was studied. Although the results confirmed PBP1 as a major lethal target for these compounds, they also underlined several weaknesses in our present understanding of this phenomenon. In growing cells, but not in resting cells, the penicillin target(s) appeared to be somewhat protected from the action of the inactivators. In vitro experiments indicated that amino acids, peptides and depsipeptides mimicking the peptide moiety of the nascent peptidoglycan significantly interfered with the acylation of PBP1 by the antibiotics. In addition, the level of PBP1 saturation at antibiotic concentrations corresponding to the minimum inhibitory concentrations was not constant, suggesting that additional, presently undiscovered, factors might be necessary to account for the experimental observations. 相似文献
108.
109.
Geoffrey C. Waldbieser Brian G. Bosworth Sylvie M. A. Quiniou 《Marine biotechnology (New York, N.Y.)》2010,12(4):380-385
Production of doubled haploids via mitotic gynogenesis is a useful tool for the creation of completely inbred fish. In order to produce viable doubled haploid channel catfish, we utilized hydrostatic pressure or thermal treatments on eggs fertilized with sperm that had been exposed to ultraviolet light. At 1.5 h post-fertilization, the embryos were exposed to either 590 kg/cm2 hydrostatic pressure for 3 min, 37°C for 5 min, or 41°C for 3 min. In the pressure-treated group, only 21 offspring hatched from five spawns with family sizes of one, two, two, four, and 12 offspring each. Eight embryos from the 37°C treatment and 32 embryos from the 41°C treatment survived to hatch. Genotype analysis using microsatellite loci demonstrated all 21 offspring resulting from pressure treatment were homozygous at the 64 loci tested, and none contained alleles unique to the donor male. Eleven of 32 offspring from the 41°C treatment were homozygous at the 18 loci tested, while 21 offspring were heterozygous at six to 12 of these loci. Again, no offspring contained alleles unique to the donor male. However, all eight offspring from the 37°C treatment were heterozygous at multiple loci, and one contained unambiguous paternal alleles. These experiments demonstrated our ability to produce viable homozygous, doubled haploid channel catfish. Doubled haploid catfish can be used to create completely inbred populations for genetic analyses, and homozygous genomic templates will be useful in gene identification and genome characterization. 相似文献
110.