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排序方式: 共有843条查询结果,搜索用时 62 毫秒
821.
822.
José Miguel Mancheño Estíbaliz Atondo Julen Tomás-Cortázar José Luís Lavín Laura Plaza-Vinuesa Itziar Martín-Ruiz Diego Barriales Ainhoa Palacios Claudio Daniel Navo Leticia Sampedro Ainize Peña-Cearra Miguel Ángel Pascual-Itoiz Janire Castelo Ana Carreras-González Donatello Castellana Aize Pellón Susana Delgado Patricia Ruas-Madiedo Blanca de las Rivas Leticia Abecia Rosario Muñoz Gonzalo Jiménez-Osés Juan Anguita Héctor Rodríguez 《Microbial biotechnology》2022,15(2):648-667
Colorectal cancer pathogenesis and progression is associated with the presence of Fusobacterium nucleatum and the reduction of acetylated derivatives of spermidine, as well as dietary components such as tannin-rich foods. We show that a new tannase orthologue of F. nucleatum (TanBFnn) has significant structural differences with its Lactobacillus plantarum counterpart affecting the flap covering the active site and the accessibility of substrates. Crystallographic and molecular dynamics analysis revealed binding of polyamines to a small cavity that connects the active site with the bulk solvent which interact with catalytically indispensable residues. As a result, spermidine and its derivatives, particularly N8-acetylated spermidine, inhibit the hydrolytic activity of TanBFnn and increase the toxicity of gallotannins to F. nucleatum. Our results support a model in which the balance between the detoxicant activity of TanBFnn and the presence of metabolic inhibitors can dictate either conducive or unfavourable conditions for the survival of F. nucleatum. 相似文献
823.
Purinergic Signalling - 相似文献
824.
Ibervillea lindheimeri is a dioecious member of the Cucurbitaceae whose male flowers possess a number of sex-specific characteristics including eglandular trichomes on the anther connective. A 2-year study (1989 and 1990) was undertaken to assess the potential for sexual selection of anther trichome number as a male floral trait that enhances pollen removal (a male fitness component). Correlation analysis of ten reproductive and floral traits showed that only the mean number of anther trichomes per flower was significantly associated with mean pollen removal per flower. Anther trichomes are two-celled, consisting of a small, caplike, apical cell and a large, bulbous basal cell. The basal cell is under tension and produces a sticky polysaccharide that is forcefully ejected upward when the apical cell is broken off by visiting bees. The sticky polysaccharide accumulates on the bees and aids in adherence of pollen. We propose that there is directional selection on individual males for number of anther trichomes per flower. The more anther trichomes per flower, the more pollen exported, and the greater the likelihood of siring seeds. Males differed significantly in mean number of anther trichomes per flower and were relatively consistent in their rank order over a 2-year period; both are prerequisites for sexual selection to operate. Selection coefficients and differentials for 1989 and 1990 were 0.005 and 0.007, and 0.22 and 0.32, respectively, and suggest moderate to strong directional selection on anther trichome number. 相似文献
825.
Marcin Okroj Leticia Corrales Anna Stokowska Ruben Pio Anna M. Blom 《Cancer immunology, immunotherapy : CII》2009,58(11):1771-1780
The complement system can be specifically targeted to tumor cells due to molecular changes on their surfaces that are recognized
by complement directly or via naturally occurring antibodies. However, tumor cells often overexpress membrane-bound complement
inhibitors protecting them from complement attack. We have previously shown that non-small cell lung cancer (NSCLC) cells,
additionally to membrane-bound inhibitors, produce substantial amounts of soluble regulators such as factor I (FI) and factor
H (FH). Since low oxygen concentration is associated with rapidly growing solid tumors, we studied how NSCLC cells protect
themselves from complement attack under hypoxic conditions. Unexpectedly, mRNA levels and secretion of both FI and FH were
significantly decreased already after 24 h exposure to hypoxia while cell viability measured by XTT assay and annexin V/7-AAD
staining was affected only marginally. Furthermore, we observed decrease of mRNA level and loss of membrane-bound complement
inhibitor CD46 and increased deposition of early (C3b) and terminal (C9) complement components on hypoxic NSCLC cells. All
three complement pathways (classical, lectin and alternative) were employed to deposit C3b on cell surface. Taken together,
our results imply that under hypoxic conditions NSCLC give up some of their available defense mechanisms and become more prone
to complement attack. 相似文献
826.
Alaide Domínguez-Calderón Antonia ávila-Flores Arturo Ponce Esther López-Bayghen José-Víctor Calderón-Salinas José Luis Reyes Bibiana Chávez-Munguía José Segovia Carla Angulo Leticia Ramírez Helios Gallego-Gutiérrez Lourdes Alarcón Dolores Martín-Tapia Pablo Bautista-García Lorenza González-Mariscal 《Molecular biology of the cell》2016,27(10):1581-1595
827.
Stefan Leu Reinhard Bolli Leticia Mendiola-Morgenthaler Arminio Boschetti 《Planta》1984,160(3):204-211
Starting from isolated chloroplasts of the Chlamydomonas reinhardii cw 15 mutant, several mRNA-containing chloroplast subfractions, i.e. thylakoid-bound polysomes, detached polysomes or isolated RNA, were prepared and incubated in homologous and heterologous translation systems. In the reticulocyte lysate these fractions gave rise to strikingly different product patterns. A most prominent difference concerned the in-vivo rapidly labelled 32,000-dalton thylakoid polypeptide. Neither this membrane protein nor its 34,000-dalton precursor was formed when membrane-containing or free polysomes were translated, while the 34,000-dalton precursor was a main product of the RNA isolated from the same membranes. The influence of thylakoid membranes during translation was also observed in homologous translation systems with lysed chloroplasts supplemented with ATP. Membrane and soluble fractions, when translated separately, yielded product patterns which differed from each other, although the RNAs extracted from the respective fractions gave the same product patterns when translated in reticulocyte lysate; the latter included a soluble protein, the large subunit of ribulose-1,5-bisphosphate carboxylase, and a membrane protein, the 34,000-dalton precursor of the 32,000-dalton membrane protein, as major labelled translation products. These results point to a regulatory role of thylakoid membranes in the expression of chloroplast mRNA and argue against compartmentation of the chloroplast mRNAs between the soluble and membrane fractions.Abbreviation SDS
sodium dodecyl sulfate 相似文献
828.
Beatriz Sánchez-Nieto Maria Romero-Expósito José Antonio Terrón Leticia Irazola Marta Paiusco Elisabetta Cagni Caterina Ghetti Silvano Filice Francisco Sánchez-Doblado 《Reports of Practical Oncology and Radiotherapy》2018,23(4):251-259
The aim of this work was to estimate peripheral neutron and photon doses associated with the conventional 3D conformal radiotherapy techniques in comparison to modern ones such as Intensity modulated radiation therapy and volumetric modulated arc therapy. Assessment in terms of second cancer incidence ought to peripheral doses was also considered. For that, a dosimetric methodology proposed by the authors has been applied beyond the region where there is no CT information and, thus, treatment planning systems do not calculate and where, nonetheless, about one third of second primary cancers occurs. 相似文献
829.
The widely used pSU8 family of cloning vectors is based on a p15A replicon and a chloramphenicol acetyltransferase (cat) gene conferring chloramphenicol resistance. We frequently observed an increase in the size of plasmids derived from these vectors. Analysis of the bigger molecular species shows that they have an IS10 copy inserted at a specific site between the promoter and the cat open reading frame. Promoter activity from both ends of IS10 has been reported, suggesting that the insertion events could lead to higher CAT production. Insertions were observed in certain constructions containing inserts that could lead to plasmid instability. To test the possibility that IS10 insertions were selected as a response to chloramphenicol selection, we have grown these constructs in the presence of different amounts of antibiotic and we observed that insertions arise promptly under higher chloramphenicol selective pressure. IS10 is present in many E. coli laboratory strains, so the possibility of insertion in constructions involving cat-containing vectors should be taken into account. Using lower chloramphenicol concentrations could solve this problem. 相似文献
830.