scholarly journals tRNA Is the Source of Low-Level trans-Zeatin Production in Methylobacterium spp.

2002 ◽  
Vol 184 (7) ◽  
pp. 1832-1842 ◽  
Author(s):  
Robbin L. Koenig ◽  
Roy O. Morris ◽  
Joe C. Polacco
Keyword(s):  
High Performance ◽  
De Novo ◽  
Zeatin Riboside ◽  
Methylotrophic Bacteria ◽  
Methylobacterium Extorquens ◽  
Culture Filtrates ◽  
Heat Treated ◽  
Soil Isolate ◽  
Gene Mutant ◽  
Leaf Surfaces

ABSTRACT Pink-pigmented facultatively methylotrophic bacteria (PPFMs), classified as Methylobacterium spp., are persistent colonizers of plant leaf surfaces. Reports of PPFM-plant dialogue led us to examine cytokinin production by PPFMs. Using immunoaffinity and high-performance liquid chromatography (HPLC) purification, we obtained 22 to 111 ng of trans-zeatin per liter from culture filtrates of four PPFM leaf isolates (from Arabidopsis, barley, maize, and soybean) and of a Methylobacterium extorquens type culture originally recovered as a soil isolate. We identified the zeatin isolated as the trans isomer by HPLC and by a radioimmunoassay in which monoclonal antibodies specific for trans-hydroxylated cytokinins were used. Smaller and variable amounts of trans-zeatin riboside were also recovered. trans-Zeatin was recovered from tRNA hydrolysates in addition to the culture filtrates, suggesting that secreted trans-zeatin resulted from tRNA turnover rather than from de novo synthesis. The product of the miaA gene is responsible for isopentenylation of a specific adenine in some tRNAs. To confirm that the secreted zeatin originated from tRNA, we mutated the miaA gene of M. extorquens by single exchange of an internal miaA fragment into the chromosomal gene. Mutant exconjugants, confirmed by PCR, did not contain zeatin in their tRNAs and did not secrete zeatin into the medium, findings which are consistent with the hypothesis that all zeatin is tRNA derived rather than synthesized de novo. In germination studies performed with heat-treated soybean seeds, cytokinin-null (miaA) mutants stimulated germination as well as wild-type bacteria. While cytokinin production may play a role in the plant-PPFM interaction, it is not responsible for stimulation of germination by PPFMs.

BRUSHFORM 96

Alloy Digest ◽  
2014 ◽  
Vol 63 (7) ◽  
Keyword(s):  
Physical Properties ◽  
Tensile Properties ◽  
High Performance ◽  
Strength Characteristics ◽  
Bend Strength ◽  
Copper Nickel ◽  
Heat Treated

Abstract BrushForm 96 strip is a high-performance, heat treatable spinodal copper-nickel-tin alloy designed to provide optimal formability and strength characteristics in conductive spring applications. It is available in both pre-heat treated (mill hardened) and heat treatable (age hardenable) forms. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. and bend strength. It also includes information on forming. Filing Code: Cu-833. Producer or source: Materion Brush Performance Alloys.

New Generation of Brake Callipers to Improve Competitiveness and Energy Savings in Very High Performance Cars

2014 ◽  
Vol 217-218 ◽  
pp. 471-480
Author(s):  
Ivano Gattelli ◽  
Gian Luigi Chiarmetta ◽  
Marcello Boschini ◽  
Renzo Moschini ◽  
Mario Rosso ◽  
...  
Keyword(s):  
High Pressure ◽  
High Performance ◽  
Energy Savings ◽  
High Reliability ◽  
A357 Alloy ◽  
Bench Tests ◽  
Heat Treated ◽  
New Generation ◽  
Non Destructive ◽  
Very High

This paper concerns with the optimisation of the innovative rheocasting process to produce a new generation of brake callipers, characterised by very high reliability and strength. The attained very promising properties favoured their use on a very high performance car and the presented technique can be further extended for other important challenging applications. The prototype components are produced using T6 heat treated A357 alloy. Results on the samples machined directly from the produced callipers are in detail described and analysed. Pieces exhibiting some small defects, individuated by non-destructive tests, as well as defectless pieces have been underlined to severe industrial tests, e.g. high pressure tight, as well as severe bench tests, and it has been observed that the proposed technological process assure the fulfilment of the requirements contained in standards.

scholarly journals Development of a partition panel of an Al6061 sheet metal part for the improvement of formability and mechanical properties by hot forming quenching

2017 ◽  
Vol 9 (2) ◽  
pp. 168781401769121 ◽  
Author(s):  
Dae-Cheol Ko ◽  
Dae-Hoon Ko ◽  
Jae-Hong Kim ◽  
Joon-Hong Park
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Preliminary Test ◽  
Hot Forming ◽  
Aluminum Sheets ◽  
Heat Treated ◽  
Quenching Process ◽  
Automotive Part ◽  
Formed Part ◽  
Quench Factor Analysis

In this study, the hot forming quenching process was investigated to improve the deficiencies that arise in materials subjected to conventional cold stamping, such as low formability and undesirable mechanical properties. The hot forming quenching process was mainly discussed in terms of formability and mechanical properties in this study and was first evaluated by preliminary tests. To examine formability, an evaluation was conducted using hot-tensile and hemispherical-dome stretching tests at temperatures of 350°C and 450°C, respectively. In addition, the mechanical properties of the formed part were predicted using quench factor analysis, which was based on the cooling temperature during the die quenching process. These preliminary test results were then used to predict the formability and hardness of the partition panel of an automotive part, where the analytical results indicated high performance of the hot forming quenching process, in contrast to conventional forming. Finally, the hot forming quenching experiment of the partition panel was carried out to validate the predicted results and the obtained formability and hardness values were compared with conventional forming at room temperature using T4 and T6 heat-treated sheets. The analytical and experimental results indicate that the hot forming quenching process is a very effective method for obtaining desirable formability and mechanical properties in the forming of aluminum sheets.

scholarly journals A parallel computational framework for ultra-large-scale sequence clustering analysis

2018 ◽  
Vol 35 (3) ◽  
pp. 380-388 ◽  
Author(s):  
Wei Zheng ◽  
Qi Mao ◽  
Robert J Genco ◽  
Jean Wactawski-Wende ◽  
Michael Buck ◽  
...  
Keyword(s):  
Parallel Computing ◽  
High Performance ◽  
Large Scale ◽  
De Novo ◽  
Rapid Development ◽  
Operational Taxonomic Unit ◽  
Supplementary Information ◽  
Computational Framework ◽  
Speed Up ◽  
Scale Sequence

Abstract Motivation The rapid development of sequencing technology has led to an explosive accumulation of genomic data. Clustering is often the first step to be performed in sequence analysis. However, existing methods scale poorly with respect to the unprecedented growth of input data size. As high-performance computing systems are becoming widely accessible, it is highly desired that a clustering method can easily scale to handle large-scale sequence datasets by leveraging the power of parallel computing. Results In this paper, we introduce SLAD (Separation via Landmark-based Active Divisive clustering), a generic computational framework that can be used to parallelize various de novo operational taxonomic unit (OTU) picking methods and comes with theoretical guarantees on both accuracy and efficiency. The proposed framework was implemented on Apache Spark, which allows for easy and efficient utilization of parallel computing resources. Experiments performed on various datasets demonstrated that SLAD can significantly speed up a number of popular de novo OTU picking methods and meanwhile maintains the same level of accuracy. In particular, the experiment on the Earth Microbiome Project dataset (∼2.2B reads, 437 GB) demonstrated the excellent scalability of the proposed method. Availability and implementation Open-source software for the proposed method is freely available at https://www.acsu.buffalo.edu/~yijunsun/lab/SLAD.html. Supplementary information Supplementary data are available at Bioinformatics online.

Endothelin synthesis by rabbit renal tubule cells

1991 ◽  
Vol 261 (2) ◽  
pp. F221-F226 ◽  
Author(s):  
D. E. Kohan
Keyword(s):  
High Performance ◽  
Renal Tubule ◽  
De Novo ◽  
Collecting Duct ◽  
Cell Types ◽  
Phospholipid Metabolism ◽  
Thick Ascending Limb ◽  
Medullary Collecting Duct ◽  
Tubule Cells ◽  
Endothelin 3

Endothelins regulate nephron sodium and water transport, prostaglandin E2 (PGE2) synthesis, and phospholipid metabolism. Recent studies suggest that renal tubule cells synthesize endothelins. To determine which nephron sites have such potential, endothelin production by cells derived from different nephron segments was examined. Immunoreactive endothelin 1 (ET-1) and endothelin 3 (ET-3) were measured in supernatants of cultured rabbit proximal tubule (PT), medullary thick ascending limb (MTAL), cortical collecting tubule (CCT), and inner medullary collecting duct (IMCD) cells. All cell types released immunoreactive ET-1 and ET-3. However, the amounts of endothelin produced differed as follows: IMCD greater than MTAL greater than CCT much greater than PT for ET-1 and IMCD greater than MTAL = PT = CCT for ET-3; in all cases ET-1 much greater than ET-3. To confirm de novo ET-3 synthesis, IMCD cells were labeled with [35S]cysteine, and the supernatant was immunoprecipitated with anti-ET-3 antibody. Sample and standard ET-3 eluted at identical positions on high-performance liquid chromatographs, confirming de novo synthesis of ET-3 by cultured IMCD cells. These data raise the possibility of an important functional role for nephron-derived endothelin and, in particular, endothelin produced by tubule cells in the medulla.

Activités physiologiques de l'ochracine, synthétisée par Septoria nodorum, sur la croissance de plantules de riz et sur la synthèse ‘de novo’ des alpha-amylases par les couches à aleurone du caryopse de blé. Interaction avec l'acide gibbérellique

1979 ◽  
Vol 57 (6) ◽  
pp. 561-567 ◽  
Author(s):  
G. Touraud ◽  
J. F. Bousquet
Keyword(s):  
Synergistic Effect ◽  
Gibberellic Acid ◽  
De Novo ◽  
Pathogenic Fungus ◽  
Septoria Nodorum ◽  
De Novo Synthesis ◽  
Rice Seedlings ◽  
Culture Filtrates ◽  
Increased Sensitivity ◽  
Tissue Permeability

Ochracine was isolated from culture filtrates of Septoria nodorum Berk. (Berk.), a pathogenic fungus of wheat. At concentrations ranging from 25 μg/mL it inhibited the growth of wheat and rice seedlings and the 'de novo' synthesis of α-amylases by the aleurone layers of wheat. These effects were not reversed by increased concentrations of gibberellic acid.Between 2.5 and 10 μg/mL, ochracine exhibited a synergistic effect with exogenous gibberellic acid on the same physiological phenomena. For these last concentrations, the results suggest an increased sensitivity of rice seedlings and wheat aleurone layers to exogenous gibberellic acid as a result of changes in tissue permeability.

Mutations in the AML1 Gene Define an Unfavorable Subgroup in Acute Myeloid Leukemia with FAB M0.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4340-4340
Author(s):  
Frank Dicker ◽  
Mirjam Klaus ◽  
Torsten Haferlach ◽  
Wolfgang Kern ◽  
Wolfgang Hiddemann ◽  
...  
Keyword(s):  
High Performance ◽  
De Novo ◽  
Mutation Screening ◽  
Point Mutations ◽  
Gene Mutations ◽  
Normal Karyotype ◽  
Runt Domain ◽  
Screening Efficiency ◽  
Genetic Aberration ◽  
Aml1 Gene

Abstract The AML1/RUNX1 gene is the most frequent target for chromosomal translocations in leukemia. Recently point mutations in the AML1 gene have been demonstrated as another mode of genetic aberration. AML1 mutations have been reported in de novo MDS and AML, as well as in therapy related MDS and AML. The AML M0 subtype has been found to be most frequently affected by sporadic AML1 gene mutations. We analysed AML1 gene mutations in a cohort of 49 M0 patients. Mutation screening was performed either with SSCP (n=21) and/or denaturating High Performance Liquid Chromatography (dHPLC) (n=33), 5 cases were analyzed by both methods. SSCP screening of exons 3–5 of the AML1 gene was carried out at the genomic level. These exons cover the socalled Runt domain, which is most frequently mutated. Fragments with aberrant mobility were sequenced. With this method 5 cases were found to be mutated. Subsequently, to improve the screening efficiency an assay using dHPLC was established. Hereby, we screened the cDNA of patient samples for mutations in amino acid codons 1–277 of the AML1b transcript, where the Runt domain is located between codons 49 and 178. All 5 cases detected by SSCP were confirmed by dHPLC. Nine mutations were detected in the cohort of 28 cases (32%) which had not been analyzed by SSCP. In total, 14 of the 49 samples (29%) tested were identified to be mutated, which is a slightly higher frequency than previously reported. In the cohort of 35 AML1 non-mutated cases 20 (57%) had a normal karyotype and 15 (43%) an aberrant karyotypes, whereas only 6 of the 14 AML1 mutated cases (43%) had a normal karyotype (p=0.001). Three of the AML1 mutated cases (21%) also had FLT3 mutations. One had an FLT3-LM, one an FLT3-TKD mutation, and one case both LM and TKD mutations. Clinical follow up data were available for 33 patients (22 AML1 non- mutated, 11 AML1 mutated). The median OS and EFS of the AML1 non-mutated versus the mutated group was 276 days versus 63 days (p = 0.0679) and 276 vs. 63 days (p=0.0630) respectively. Thus the AML1 mutated cases tend to have a worse clinical outcome. When other AML subtypes were screened for AML1 mutations, i.e. M1 (n=26), M2 (n=21) and M4 (n=3), only 1 additional AML1 mutation was detected, confirming the highest prevalence of AML1 mutations in M0. In conclusion, 1) we established a new assay to screen for AML1 mutations. 2) We confirmed the high incidence of AML1 gene mutations in AML M0, both in cases with normal and aberrant karyotype. 3) For the first time we demonstrated that AML1 mutations define an unfavorable subentity in AML M0.

scholarly journals Tropical bat as mammalian model for skin carotenoid metabolism

2016 ◽  
Vol 113 (39) ◽  
pp. 10932-10937 ◽  
Author(s):  
Ismael Galván ◽  
Juan Garrido-Fernández ◽  
José Ríos ◽  
Antonio Pérez-Gálvez ◽  
Bernal Rodríguez-Herrera ◽  
...  
Keyword(s):  
High Performance ◽  
De Novo ◽  
Carotenoid Pigments ◽  
Physiological Mechanisms ◽  
Flight Mass Spectrometry ◽  
Animal Physiology ◽  
Bright Yellow ◽  
Carotenoid Metabolism ◽  
Potential Capacity ◽  
Bright Color

Animals cannot synthesize carotenoid pigments de novo, and must consume them in their diet. Most mammals, including humans, are indiscriminate accumulators of carotenoids but inefficiently distribute them to some tissues and organs, such as skin. This limits the potential capacity of these organisms to benefit from the antioxidant and immunostimulatory functions that carotenoids fulfill. Indeed, to date, no mammal has been known to have evolved physiological mechanisms to incorporate and deposit carotenoids in the skin or hair, and mammals have therefore been assumed to rely entirely on other pigments such as melanins to color their integument. Here we use high-performance liquid chromatography (HPLC) in combination with time-of-flight mass spectrometry (HPLC-TOF/MS) to show that the frugivorous Honduran white bat Ectophylla alba colors its skin bright yellow with the deposition of the xanthophyll lutein. The Honduran white bat is thus a mammalian model that may help developing strategies to improve the assimilation of lutein in humans to avoid macular degeneration. This represents a change of paradigm in animal physiology showing that some mammals actually have the capacity to accumulate dietary carotenoids in the integument. In addition, we have also discovered that the majority of the lutein in the skin of Honduran white bats is present in esterified form with fatty acids, thereby permitting longer-lasting coloration and suggesting bright color traits may have an overlooked role in the visual communication of bats.

Optimization of Heat Treatment Cycles for Automotive Parts Produced by Rheocasting Process

2006 ◽  
Vol 116-117 ◽  
pp. 505-508 ◽  
Author(s):  
Mario Rosso ◽  
Marco Actis Grande
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
High Performance ◽  
Treatment Cycle ◽  
Total Cost ◽  
Heat Treatment Cycle ◽  
Dimensional Precision ◽  
Heat Treated ◽  
Automotive Parts ◽  
High Level

This work aims at studying the possibility of optimising the heat treatment cycles of parts produced using the New Rheocasting process in order to reduce the total cost of the operation, attaining good mechanical properties for high performance parts. The mechanical properties and the microstructure features of the considered A 356 alloy and the relative produced parts have been analysed and studied on samples machined both from the as cast and from the heat treated compomnents. The obtained results showed the possibility of successfully modifying the T6 heat treatment cycle with economical benefits, maintaining at the same time comparable high level properties and performances, together with good dimensional precision.

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