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61.
Suleyman Sandal Bayram Yilmaz David O. Carpenter 《Mutation Research - Genetic Toxicology and Environmental Mutagenesis》2008,654(1):88-92
Polychlorinated biphenyls (PCBs) are known to be carcinogenic, but the mechanisms of this action are uncertain. Most, but not all, studies have concluded that PCBs are not directly mutagenic, and that much if not all of the carcinogenic activity resides in the fraction of the PCB mixture that contains congeners with dioxin-like activity. The present study was designed to determine genotoxic effects of an ortho-substituted, non-coplanar congener, 2,2′,5,5′-tetrachlorobiphenyl (PCB 52), and a non-ortho-substituted coplanar congener with dioxin-like activity, 3,3′,4,4′-tetrachlorobiphenyl (PCB 77) on cultured human peripheral lymphocytes. DNA damage was assessed by use of the comet assay (alkaline single-cell gel electrophoresis). After cell cultures were prepared, test groups were treated with different concentrations of PCB 52 (0.2 and 1 μM) and PCB 77 (1 and 10 μM) for 1 h at 37 °C in a humidified carbon dioxide incubator, and compared to a DMSO vehicle control group. The cells were visually classified into four categories on the basis of extent of migration such as undamaged (UD), low damage (LD), moderate damage (MD) and high damage (HD). The highest concentration of PCBs 52 and 77 significantly increased DNA breakage in human lymphocytes (p < 0.001). Our results indicate that both the non-coplanar PCB 52 and coplanar PCB 77 cause DNA damage, and that the ortho-substituted congener was significantly more potent than the dioxin-like coplanar congener. 相似文献
62.
Aspergillus fumigatus protein phosphatase PpzA is involved in iron assimilation,secondary metabolite production,and virulence
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63.
Hatice Akkaya Ertugrul Kilic Signem Eyuboglu Dinc Bayram Yilmaz 《Journal of biochemical and molecular toxicology》2014,28(8):373-377
Apart from its effect on the regulation of reproductive function, recent studies indicate that kisspeptin may play roles in the antioxidant defense system. The antioxidant defense system and oxidative stress contribute to the etiology and pathogenesis of neuronal cell death after brain injury. We have investigated the postacute effect of kisspeptin‐10 on brain injury induced by l ‐methionine. DNA fragmentation, malondialdehyde (MDA), reduced glutathione levels, and superoxide dismutase (SOD) activities were analyzed. Our results showed that methionine treatment increases apoptotic cell death. Kisspeptin alone showed no side effect on apoptotic cell death. However, kisspeptin treatment reversed the proapoptotic effect of methionine associated with reduced MDA and increased glutathione levels. Furthermore, SOD activity was completely depleted in methionine‐treated animals. In conclusion, our results revealed that delayed kisspeptin‐10 treatment reduces neuronal cell death by activation of SOD activity. 相似文献
64.
In earlier work we have described how computer algebra may be used to derive composite rate laws for complete systems of equations, using the mathematical technique of Gröbner Bases (Bennett, Davenport and Sauro, 1988). Such composite rate laws may then be fitted to experimental data to yield estimates of kinetic parameters. Recently we have been investigating the practical application of this methodology to the estimation of kinetic parameters for the closed two enzyme system of aspartate aminotransferase (AAT) and malate dehydrogenase (MDH) (Fisher 1990a; Fisher 1990b; Bennett and Fisher, 1990): $$\begin{gathered} aspartate + \alpha - ketoglutarate\begin{array}{*{20}c} \rightharpoonup \\ \leftharpoondown \\ \end{array} glutamate + oxaloacetate \hfill \\ {\text{oxaloacetate + NADH}}\begin{array}{*{20}c} \rightharpoonup \\ \leftharpoondown \\ \end{array} malate + NAD^ + \hfill \\ \end{gathered} $$ In this paper we present a fuller (although not yet complete) analysis of the system. We show how symbolic estimates of the error behaviour of the parameters can be made, and used to identify those which are of kinetic significance. Finally we consider how metabolic control analysis can be applied directly to such a system. 相似文献
65.
Ahmet Bayram Gianandrea Salerno Eric Conti Eric Wajnberg Ferdinando Bin & Serpil Kornoor 《Entomologia Experimentalis et Applicata》2004,111(2):141-149
Telenomus busseolae Gahan (Hymenoptera: Scelionidae) is an important egg parasitoid of noctuid stem borers of gramineous crops, attacking egg masses of Sesamia spp. Under natural conditions, and whatever the host species attacked, these egg masses are generally concealed under the leaf sheaths or other narrow spaces, and vary greatly in size. In the work presented here, the influence of host patch size (4, 8, 16, 32, 64, or 128 eggs per mass) on the sex ratio and sex sequence pattern of ovipositing T. busseolae was investigated in the laboratory using Sesamia nonagrioides (Lefebvre) (Lepidoptera: Noctuidae) as host. The results are similar to those described for other parasitoids of aggregated hosts, and are in accordance with the Local Mate Competition model. With increasing egg mass size, the overall sex ratio (proportion of males) decreased, although additional males were laid at the end of the sequence in the larger masses (64 and 128 eggs). Sex sequence pattern always followed a males‐first strategy, i.e., with a higher proportion of males at the beginning, but the whole sex ratio sequence was influenced by the size of the egg mass. Such results in a parasitoid of concealed eggs are compared to those observed in parasitoids of exposed eggs and discussed in terms of parasitoid reproductive strategies and evolutionary adaptations. 相似文献
66.
Mü?erref?Tatman-OtkunEmail author ?aban?Gürcan Bur?in??zer Bayram?Aydoslu ?ebnem?Bukavaz 《BMC microbiology》2005,5(1):24
Background
Stenotrophomonas maltophilia is inherently resistant to many antimicrobials. So far, antimicrobial susceptibility tests for S. maltophilia have not been fully standardized. The purpose of the study was to compare the susceptibility of S. maltophilia isolates against seven different antimicrobials using three different methods and to investigate their genetic relatedness. 相似文献67.
Sureyya Sarıhan Ahmet Sami Bayram Cengiz Gebitekin Omer Yerci Deniz Sıgırlı 《Reports of Practical Oncology and Radiotherapy》2018,23(2):97-104
Aim
The aim of this study was to evaluate thymic epithelial tumors (TETs) for treatment outcomes and prognostic factors on survival.Background
TETs are very rare neoplasms and multidisciplinary approach is recommended according to prognostic factors.Materials and methods
Between 1995 and 2013, 31 patients were treated with median 5400 cGy (range: 1620–6596 cGy) radiotherapy (RT). Eleven patients received adjuvant or concurrent chemotherapy. There were 25 thymomas, 4 thymic carcinomas and 2 thymic neuroendocrin carcinomas. According to Masaoka, staging and WHO classification, cases were divided to good (n: 10), moderate (n: 9) and poor (n: 12) prognostic risk groups. Survival was calculated from diagnosis.Results
In January 2016, 22 cases were alive with median 51.5 months (range: 2–170.5) follow-up. Recurrences were observed in 29% of patients in median 29.5 months (range: 6.5–105). Local control, mean overall (OS) and disease-free survival (DFS) rates were 86%, 119 and 116 months, respectively. There was a significant difference for R0 vs. R+ resection (81% vs. 43%, p = 0.06, and 69% vs. 46%, p = 0.05), Masaoka stage I–II vs. III–IV (75% vs. 52%, p = 0.001, and 75% vs. 37%, p < 0.001), and also prognostic risk groups (100% vs. 89% vs. 48%, p = 0.003, and 100% vs. 87% vs. 27%, p = 0.004) in terms of 5-year OS and DFS, respectively.Conclusion
In our study, prognostic risk stratification was shown to be a significant predictor of survival. There is a need to investigate subgroups that may or may not benefit from adjuvant RT. 相似文献68.
A new subspecies of the Bille’s Lycian Salamander Lyciasalamandra billae is described from four localities in the vicinity of Geyikbay?r? nearby Antalya, Turkey. It is distinguished from the nominotypical subspecies by colouration and surface pattern. The distribution area of the new subspecies is nested within the range of Lyciasalamandra antalyana, with L. a. gocmeni bordering in the north and the range of L. a. antalyana bordering in the south. New localities of both L. antalyana subspecies are reported.http://www.zoobank.org/urn:lsid:zoobank.org:pub:8F541E98-61F3-4EDD-A432614B0A250711 相似文献
69.
New insights into the history of domesticated and wild apricots and its contribution to Plum pox virus resistance
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Stéphane Decroocq Amandine Cornille David Tricon Sevda Babayeva Aurélie Chague Jean‐Philippe Eyquard Raul Karychev Svetlana Dolgikh Tatiana Kostritsyna Shuo Liu Weisheng Liu Wenjuan Geng Kang Liao Bayram M. Asma Zeynal Akparov Tatiana Giraud Véronique Decroocq 《Molecular ecology》2016,25(19):4712-4729
Studying domesticated species and their wild relatives allows understanding of the mechanisms of population divergence and adaptation, and identifying valuable genetic resources. Apricot is an important fruit in the Northern hemisphere, where it is threatened by the Plum pox virus (PPV), causing the sharka disease. The histories of apricot domestication and of its resistance to sharka are however still poorly understood. We used 18 microsatellite markers to genotype a collection of 230 wild trees from Central Asia and 142 cultivated apricots as representatives of the worldwide cultivated apricot germplasm; we also performed experimental PPV inoculation tests. The genetic markers revealed highest levels of diversity in Central Asian and Chinese wild and cultivated apricots, confirming an origin in this region. In cultivated apricots, Chinese accessions were differentiated from more Western accessions, while cultivated apricots were differentiated from wild apricots. An approximate Bayesian approach indicated that apricots likely underwent two independent domestication events, with bottlenecks, from the same wild population. Central Asian native apricots exhibited genetic subdivision and high frequency of resistance to sharka. Altogether, our results contribute to the understanding of the domestication history of cultivated apricot and point to valuable genetic diversity in the extant genetic resources of wild apricots. 相似文献
70.
Janson J. White Juliana F. Mazzeu Zeynep Coban-Akdemir Yavuz Bayram Vahid Bahrambeigi Alexander Hoischen Bregje W.M. van Bon Alper Gezdirici Elif Yilmaz Gulec Francis Ramond Renaud Touraine Julien Thevenon Marwan Shinawi Erin Beaver Jennifer Heeley Julie Hoover-Fong Ceren D. Durmaz Halil Gurhan Karabulut Claudia M.B. Carvalho 《American journal of human genetics》2018,102(1):27-43