排序方式: 共有111条查询结果,搜索用时 0 毫秒
81.
Staneva J Trendafilova-Savkova A Todorova MN Evstatieva L Vitkova A Staneva J Trendafilova-Savkova A Todorova MN Evstatieva L Vitkova A 《Zeitschrift für Naturforschung. C, Journal of biosciences》2004,59(3-4):161-165
The aerial parts of Anthemis austriaca Jacq. afforded five new sesquiterpene lactones (two of which are dimeric guaianolides) and three new guaiane type sesquiterpene acids In addition, seven known terpenoids were also found in the studied species. Their structures were elucidated by spectral methods. 相似文献
82.
Tsoncheva VL Todorova KA Ivanov IG Maximova VA 《Zeitschrift für Naturforschung. C, Journal of biosciences》2005,60(7-8):644-648
A simple method for spontaneous transfection into mammalian cells (both adherent and suspension in culture) with plasmid DNA is described. This method does not require any specific DNA carrier or technical device and can be applied for obtaining both transient and stably transfected cells. The efficiency of spontaneous transfection is slightly lower in comparison with that of the conventional calcium phosphate and lipofectin transfection methods and does not depend on the type of cell culture used. 相似文献
83.
Copper and cadmium inhibited the growth as well as citric acid production (depending on the heavy metal concentrations) by
citric-acid-producingAspergillus niger. Activity of citrate synthase was connected with citrate synthesis in the absence as well as in the presence of heavy metals.
The activity of aconitase, and both NAD- and NADP-isocitrate dehydrogenases was strongly inhibited by copper. The contents
of DNA and proteins in the cells decreased but the contents of lipids and polysaccharides increased considerably in the presence
of both heavy metals. 相似文献
84.
Kuzmanov A Hayrabedyan S Karaivanov M Todorova K 《Folia histochemica et cytobiologica / Polish Academy of Sciences, Polish Histochemical and Cytochemical Society》2007,45(2):75-80
The present study examines the expression of p63, glutathione S-transferase-pi (GSTP1) and alpha-methylacyl-CoAracemase (AMACR) in serial slices in proliferative inflammatory atrophy (PIA) in order to implicate that some of the basal cells are probably the putative human prostate carcinoma stem cells (PHPCSC). Archived tissue sections obtained after radical prostatectomy from cases (n=30) comprising of PIA were tested using immunohistochemistry with antibodies against AMACR (Dako), p63 and GSTP1 (Labvision) and visualized by biotin-streptavidin-peroxidase kit (DAKO LSAB 2 kit). Quantitative immunohistochemistry analysis (QIHC) of the studied antigen expression levels revealed that there are two populations of p63 basal cells. Type I basal cells had high AMACR, low GSTP1 and p63 expression. Type II basal cells had low AMACR, high GSTP1 and p63 expression. Therefore, we propose that the putative human prostate carcinoma stem cells probably reside within the population of type I basal cells. 相似文献
85.
86.
Type 2 diabetes whole-genome association study in four populations: the DiaGen consortium 总被引:12,自引:0,他引:12 下载免费PDF全文
Salonen JT Uimari P Aalto JM Pirskanen M Kaikkonen J Todorova B Hyppönen J Korhonen VP Asikainen J Devine C Tuomainen TP Luedemann J Nauck M Kerner W Stephens RH New JP Ollier WE Gibson JM Payton A Horan MA Pendleton N Mahoney W Meyre D Delplanque J Froguel P Luzzatto O Yakir B Darvasi A 《American journal of human genetics》2007,81(2):338-345
Type 2 diabetes (T2D) is a common, polygenic chronic disease with high heritability. The purpose of this whole-genome association study was to discover novel T2D-associated genes. We genotyped 500 familial cases and 497 controls with >300,000 HapMap-derived tagging single-nucleotide-polymorphism (SNP) markers. When a stringent statistical correction for multiple testing was used, the only significant SNP was at TCF7L2, which has already been discovered and confirmed as a T2D-susceptibility gene. For a replication study, we selected 10 SNPs in six chromosomal regions with the strongest association (singly or as part of a haplotype) for retesting in an independent case-control set including 2,573 T2D cases and 2,776 controls. The most significant replicated result was found at the AHI1-LOC441171 gene region. 相似文献
87.
Jianhua Xiong Dilyana Todorova Ning-Yuan Su Jinchul Kim Pei-Jen Lee Zhouxin Shen Steven P. Briggs Yang Xu 《The Journal of cell biology》2015,208(5):513-520
Mouse embryonic stem cells (ESCs) are genetically more stable than somatic cells, thereby preventing the passage of genomic abnormalities to their derivatives including germ cells. The underlying mechanisms, however, remain largely unclear. In this paper, we show that the stemness factor Sall4 is required for activating the critical Ataxia Telangiectasia Mutated (ATM)–dependent cellular responses to DNA double-stranded breaks (DSBs) in mouse ESCs and confer their resistance to DSB-induced cytotoxicity. Sall4 is rapidly mobilized to the sites of DSBs after DNA damage. Furthermore, Sall4 interacts with Rad50 and stabilizes the Mre11–Rad50–Nbs1 complex for the efficient recruitment and activation of ATM. Sall4 also interacts with Baf60a, a member of the SWI/SNF (switch/sucrose nonfermentable) ATP-dependent chromatin-remodeling complex, which is responsible for recruiting Sall4 to the site of DNA DSB damage. Our findings provide novel mechanisms to coordinate stemness of ESCs with DNA damage response, ensuring genomic stability during the expansion of ESCs. 相似文献
88.
Nevena Todorova Adam J. Makarucha Nicholas D. M. Hine Arash A. Mostofi Irene Yarovsky 《PLoS computational biology》2013,9(12)
Experimental studies have demonstrated that nanoparticles can affect the rate of protein self-assembly, possibly interfering with the development of protein misfolding diseases such as Alzheimer''s, Parkinson''s and prion disease caused by aggregation and fibril formation of amyloid-prone proteins. We employ classical molecular dynamics simulations and large-scale density functional theory calculations to investigate the effects of nanomaterials on the structure, dynamics and binding of an amyloidogenic peptide apoC-II(60-70). We show that the binding affinity of this peptide to carbonaceous nanomaterials such as C60, nanotubes and graphene decreases with increasing nanoparticle curvature. Strong binding is facilitated by the large contact area available for π-stacking between the aromatic residues of the peptide and the extended surfaces of graphene and the nanotube. The highly curved fullerene surface exhibits reduced efficiency for π-stacking but promotes increased peptide dynamics. We postulate that the increase in conformational dynamics of the amyloid peptide can be unfavorable for the formation of fibril competent structures. In contrast, extended fibril forming peptide conformations are promoted by the nanotube and graphene surfaces which can provide a template for fibril-growth. 相似文献
89.
D. Todorova I. Vaseva J. Malbeck A. Trávníčková I. Macháčková E. Karanov 《Biologia Plantarum》2007,51(3):579-583
Changes in endogenous cytokinin (CK) content and cytokinin oxidase/dehydrogenase activity (CKX) in response to gibberellic
acid (GA3) in two pea cultivars with different life span were assessed. The control leaves of cv. Scinado, which developed faster,
had higher initial cytokinin content and lower CKX activity, while opposite trend was observed in cv. Manuela with longer
life span. Increased CKX and decreased CK content were detected in leaves of cv. Scinado after treatments with 0.5, 1 and
5 μM GA3. Changes in CK content and CKX activity in GA3-treated cv. Manuela leaves were reciprocal to those in cv. Scinado. CK content and CKX activity in roots were not significantly
influenced by the application of GA3. The slight repression of CKX activity in some of the root samples was accompanied by increased isopentenyladenine and isopentenyladenine
riboside content. Obtained results suggest that CKX was responsible for the changes in endogenous cytokinin pool in GA3-treated plants and most probably this enzyme represents an important link in GA/cytokinin cross talk. 相似文献
90.
Tatina T. Todorova Ventsislava Y. Petrova Stéphane Vuilleumier Anna V. Kujumdzieva 《Archives of microbiology》2009,191(11):837-845
Growth of Saccharomyces cerevisiae
ure2Δ mutant strain was investigated in the presence of diverse oxidant compounds. The inability of the strain to grow on a medium
supplemented with H2O2 was confirmed and a relationship between diminishing levels of glutathione (GSH) and peroxide sensitivity was established.
Data for the lack of significant effect of URE2 disruption on the cellular growth in the presence of paraquat and menadione were obtained. The possible role of Ure2p in
acquiring sensitivity to oxidative stress by means of its regulatory role in the GATA signal transduction pathway was discussed.
It was suggested that the susceptibility of ure2Δ mutant to the exogenous hydrogen peroxide can result from increased GSH degradation due to the deregulated localization of
the γ-glutamyl transpeptidase activating factors Gln3/Gat1. The important role of Ure2p in in vivo glutathione-mediated reactive
oxygen species (ROS) scavenging was shown by measuring the activity of antioxidant enzymes glutathione peroxidase, superoxide
dismutase (SOD) and catalase in an URE2 disrupted strain. A time-dependent increase in SOD and catalase activity was observed. More importantly, it was shown that
the ure2 mutation could cause significant disturbance in cellular oxidant balance and increased ROS level. 相似文献