Auswahl der wissenschaftlichen Literatur zum Thema „Sigma TN“

1041 Background: Identification of gene expression-based breast cancer subtypes is considered a critical means of prognostication. Genetic mutations along with epigenetic alterations contribute to gene-expression changes occurring in breast cancer. However, the reproducibility of differential DNA methylation discoveries for cancer and the relationship between DNA methylation and aberrant gene expression have not been systematically analysed. The present study was undertaken to dissect the breast cancer methylome and to deliver specific epigenotypes associated with particular breast cancer subtypes. Methods: By using Real Time QMSPCR SYBR green we analyzed DNA methylation in regulatory regions of 107 pts with breast cancer and analyzed association with prognostics factor in triple negative breast cancer and methylation promoter ESR1, APC, E-Cadherin, Rar B and 14-3-3 sigma. Results: We identified novel subtype-specific epigenotypes that clearly demonstrate the differences in the methylation profiles of basal-like and human epidermal growth factor 2 (HER2)-overexpressing tumors. Of the cases, 37pts (40%) were Luminal A (LA), 32pts (33%) Luminal B (LB), 14pts (15%) Triple-negative (TN), and 9pts (10%) HER2+. DNA hypermethylation was highly inversely correlated with the down-regulation of gene expression. Methylation of this panel of promoter was found more frequently in triple negative and HER2 phenotype. ESR1 was preferably associated with TN(80%) and HER2+(60%) subtype. With a median follow up of 6 years, we found worse overall survival (OS) with more frequent ESR1 methylation gene(p>0.05), Luminal A;ESR1 Methylation OS at 5 years 81% vs 93% when was ESR1 Unmethylation. Luminal B;ESR1 Methylation 86% SG at 5 years vs 92% in Unmethylation ESR1. Triple negative;ESR1 Methylation SG at 5 years 75% vs 80% in unmethylation ESR1. HER2;ESR1 Methylation SG at 5 years was 66.7% vs 75% in unmethylation ESR1. Conclusions: Our results provide evidence that well-defined DNA methylation profiles enable breast cancer subtype prediction and support the utilization of this biomarker for prognostication and therapeutic stratification of patients with breast cancer.

Field-grown seedlings of ‘Alamo’ switchgrass (Panicum virgatum L.) from Vonore, TN exhibited light brown-to-dark brown leaf spots and general chlorosis in June 2009. Symptomatic leaf tissue was surface sterilized (95% ethanol for 1 min, 20% commercial bleach for 3 min, and 95% ethanol for 1 min), air dried on sterile filter paper, and plated on 2% water agar amended with 10 mg/liter rifampicin (Sigma-Aldrich, St. Louis, MO) and 5 μl/liter miticide (2.4 EC Danitol, Valent Chemical, Walnut Creek, CA). Plates were incubated at 26°C for 4 days in darkness. An asexual, dematiaceous mitosporic fungus was isolated and transferred to potato dextrose agar. Cultures were transferred to Alternaria sporulation medium (3) to induce conidial production. Club-shaped conidia were produced in chains with branching of chains present. Conidia were 27 to 50 × 10 to 15 μm, with an average of 42.5 × 12.5 μm. Morphological features and growth on dichloran rose bengal yeast extract sucrose agar were consistent with characteristics described previously for Alternaria alternata (1). Pathogenicity studies were conducted with 5-week-old ‘Alamo’ switchgrass plants grown from surface-sterilized seed. Nine pots with approximately 20 plants each were prepared. Plants were wounded by trimming the tops. Eight replicate pots were sprayed with a conidial spore suspension of 5.0 × 106 spores/ml sterile water and subjected to high humidity by enclosure in a plastic bag for 7 days. One pot was sprayed with sterile water and subjected to the same conditions to serve as a control. Plants were maintained in a growth chamber at 25/20°C with a 12-h photoperiod. Foliar leaf spot symptoms appeared 5 to 10 days postinoculation for all replicate pots inoculated with A. alternata. Symptoms of A. alternata infection were not observed on the control. Lesions were excised, surface sterilized, plated on water agar, and identified in the same manner as previously described. The internal transcribed spacer (ITS) region of ribosomal DNA and the mitochondrial small sub-unit region (SSU) from the original isolate and the reisolate recovered from the pathogenicity assay were amplified with PCR, with primer pairs ITS4 and ITS5 and NMS1 and NMS2, respectively. Resultant DNA fragments were sequenced and submitted to GenBank (Accession Nos. HQ130485.1 and HQ130486.1). A BLAST search (BLASTn, NCBI) was run against GenBank isolates. The ITS region sequences were 537 bp and matched 100% max identity with eight A. alternata isolates, including GenBank Accession No. AB470838. The SSU sequences were 551 bp and matched 100% max identity with seven A. alternata isolates, including GenBank Accession No. AF229648. A. alternata has been reported from switchgrass in Iowa and Oklahoma (2); however, this is the first report of A. alternata causing leaf spot on switchgrass in Tennessee. Switchgrass is being studied in several countries as a potentially important biofuel source, but understanding of the scope of its key diseases is limited. References: (1) B. Andersen et al. Mycol. Res. 105:291, 2001. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , September 22, 2011. (3) E. A. Shahin and J. F. Shepard. Phytopathology 69:618, 1979.

There are few reports on diseases of switchgrass. In November 2009, light brown to white bleached spots (1 to 2 × 3 to 4 μm) were observed on ‘Alamo’ switchgrass (Panicum virgatum L.) grown in a growth chamber in Knoxville, TN, from surface-disinfested seed produced in Colorado. Symptomatic leaf tissue was surface sterilized, air dried, and plated on 2% water agar (WA) amended with 6.9 mg fenpropathrin/liter (Danitol 2.4 EC, Valent Chemical, Walnut Creek, CA) and 10 mg/liter rifampicin (Sigma-Aldrich, St. Louis, MO). Plates were incubated at 26°C in the dark for 5 days. A sporulating, dematiaceous, mitosporic fungus was observed and transferred to potato dextrose agar. Colonies were white to gray, with brown as conidia increased. Conidia ranged in size from 10 to 22.5 × 20 to 37.5 (average 15.2 × 26.5) μm. Conidia were golden to dark brown, broadly ellipsoidal, some pyriform, with one longitudinal septum and two to three transverse septa, sometimes constricted at the transverse septa. Based on microscopic examination, the fungus was identified as Pithomyces chartarum (Berk. & Curt.) M.B. Ellis (1); observations were consistent with the authority (2). Pathogenicity assays were conducted with 5-week-old ‘Alamo’ switchgrass grown from seed scarified with 60% sulfuric acid and surface-sterilized with 50% bleach. Seed were sown in 9 × 9-cm pots containing 50% (v/v) ProMix Potting and Seeding Mix (Premier Tech Horticulture, Québec, Canada) and 50% Turface ProLeague (Profile Products, Buffalo Grove, IL). Eight replicate pots with ~20 plants each were sprayed with a spore suspension of 5.7 × 105 spores/ml sterile water prepared from 6-day-old cultures grown on V8 juice agar in the dark. Two more pots were sprayed with sterile water to serve as controls. All plants were subjected to high humidity for 72 h by enclosure in a plastic bag. Plants were placed in a growth chamber at 25/20°C with a 12-h photoperiod. Leaf spot symptoms similar to the original disease were evident on plants in each of the eight replicate pots 6 to 10 days post-inoculation. Control plants had no symptoms. Lesions were excised from leaves, surface sterilized, and plated on WA. The resulting cultures were again identified as P. chartarum based on morphology. The internal transcribed spacer (ITS) region of rDNA from the original isolate and the pathogen recovered from plants in the pathogenicity tests were amplified with PCR using primers ITS4 and ITS5. PCR amplicons were obtained from both isolates, sequenced, and found to have 100% identity. A 580-bp sequence was deposited at GenBank (Accession No. JQ406588). The nucleotide sequence had 98 to 100% identity to the ITS sequences of isolates of Leptosphaerulina chartarum (anamorph: P. chartarum), including isolate Mxg-KY09-s4 (GU195649) from leaf spot on Miscanthus × giganteus in Kentucky (1), and isolates from leaf lesions on wheat (EF489400 and JX442978). To our knowledge, leaf spot caused by P. chartarum has not been described on switchgrass (3). Pithomyces chartarum is a seedborne pathogen of switchgrass, and may play a role in stand establishment. References: (1) M. O. Ahonsi et al. Plant Dis. 94:480, 2010. (2) M. B. Ellis. Dematiaceous Hyphomycetes. Commonwealth Mycological Institute, Kew, Surrey, England. 1971. (3) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology and Microbiology Laboratory, ARS, USDA, Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , 18 January 2013.

Abstract We introduce a non-increasing tree growth process $((T_n,{\sigma}_n),\, n\ge 1)$ , where T n is a rooted labelled tree on n vertices and σ n is a permutation of the vertex labels. The construction of (T n , σ n ) from (Tn−1, σn−1) involves rewiring a random (possibly empty) subset of edges in Tn−1 towards the newly added vertex; as a consequence Tn−1 ⊄ T n with positive probability. The key feature of the process is that the shape of T n has the same law as that of a random recursive tree, while the degree distribution of any given vertex is not monotone in the process. We present two applications. First, while couplings between Kingman’s coalescent and random recursive trees were known for any fixed n, this new process provides a non-standard coupling of all finite Kingman’s coalescents. Second, we use the new process and the Chen–Stein method to extend the well-understood properties of degree distribution of random recursive trees to extremal-range cases. Namely, we obtain convergence rates on the number of vertices with degree at least $c\ln n$ , c ∈ (1, 2), in trees with n vertices. Further avenues of research are discussed.

ABSTRACTA network of genes and at least two peptide signaling molecules tightly control whenStreptococcus mutansbecomes competent to take up DNA from its environment. Widespread changes in the expression of genes occur whenS. mutansis presented with competence signal peptidesin vitro, including the increased production of the alternative sigma factor, ComX, which activates late competence genes. Still, the way that gene products that are regulated by competence peptides influence DNA uptake and cellular physiology are not well understood. Here, we developed and employed comprehensive transposon mutagenesis of theS. mutansgenome, with a screen to identify mutants that aberrantly expressedcomX, coupled with transposon sequencing (Tn-seq) to gain a more thorough understanding of the factors modulatingcomXexpression and progression to the competent state. The screens effectively identified genes known to affect competence, e.g.,comR,comS,comD,comE,cipB,clpX,rcrR, andciaH, but disclosed an additional 20 genes that were not previously competence associated. The competence phenotypes of mutants were characterized, including by fluorescence microscopy to determine at which stage the mutants were impaired forcomXactivation. Among the novel genes studied were those implicated in cell division, the sensing of cell envelope stress, cell envelope biogenesis, and RNA stability. Our results provide a platform for determining the specific chemical and physical cues that are required for genetic competence inS. mutans, while highlighting the effectiveness of using Tn-seq inS. mutansto discover and study novel biological processes.IMPORTANCEStreptococcus mutansacquires DNA from its environment by becoming genetically competent, a physiologic state triggered by cell-cell communication using secreted peptides. Competence is important for acquiring novel genetic traits and has a strong influence on the expression of virulence-associated traits ofS. mutans. Here, we used transposon mutagenesis and genomic technologies to identify novel genes involved in competence development. In addition to identifying genes previously known to be required forcomXexpression, 20 additional genes were identified and characterized. The findings create opportunities to diminish the pathogenic potential ofS. mutans, while validating technologies that can rapidly advance our understanding of the physiology, biology, and genetics ofS. mutansand related pathogens.

Uma sigla tende cada vez mais a fazer parte do vocabulário e do cotidiano do sofrido povo latino-americano: Alca. Apresentada como irreversível pelo governo dos EUA, a Área de Livre Comércio das Américas, prevista para vigorar em 2005, afetará drasticamente a situação dos trabalhadores da região, com profundos e destrutivos impactos nos empregos, nos salários e nas suas condições de vida e trabalho. Negociada às pressas e de maneira sigilosa, a Alca objetiva servir aos interesses dos empresários norteamericanos, representando uma forma de anexação do continente, um novo e cruel tipo de colonialismo.

This master’s thesis deals with analysis and following optimisation of a Sigma TN sports car suspension. Knowledge of vehicle dynamics and strength of materials was used during the optimisation. Kinematic and force analysis was carried out in software ADAMS Car. A FEM analysis was processed in Ansys Workbench environment. Three design concepts were worked out, in which Topology optimisation also found use.