117,420 research outputs found
PRODUCTION IN ESCHERICHIA-COLI OF ACTIVE SORGHUM PHOSPHOENOLPYRUVATE CARBOXYLASE WHICH CAN BE PHOSPHORYLATED
No full textPhosphoenolpyruvate carboxylase (PEPC)-deficient mutants of Escherichia coli have been complemented with a plasmid bearing a full-length cDNA encoding the C4-type form of Sorghum leaf PEPC. Transformed cells grew on minimal medium. Two clones were selected which produce a functional and full-sized enzyme protein as determined by activity assays, immunochemical behavior and SDS-PAGE. In addition, regulatory phosphorylation of immunopurified recombinant PEPC was observed when the enzyme was incubated with a partially purified plant PEPC kinase. These results establish that E. coli cells produce a genuine, phosphate-free, higher-plant PEPC. Application of immunoadsorbtion chromatography to bacterial extracts makes it possible to prepare highly pure protein available for biochemical studies. RI Vidal, Jean/A-8881-2008; Lepiniec, Loic/G-5808-201
Interactions of nitrogen and carbon metabolism: implications of PEP-carboxylase and isocitrate dehydrogenase
No full textCamelina [Camelina sativa (L.) Crantz] seeds as a multi-purpose feedstock for bio-based applications
No full textCamelina [Camelina sativa (L.) Crantz] is an oilseed crop belonging to the Brassicaceae family that has attracted worldwide attention because of its agronomic and qualitative characteristics. This crop can adapt well to different environments and produce oil suitable for multiple bio-based uses. The most commonly measured and reported components of camelina seeds are fatty acids, proteins, and vitamins. However, they also contain specialized metabolites (SMs, formerly known as "secondary metabolites") retained in the meal, which have not been fully characterized. This work presents a long-term study conducted from 2015 to 2019 at the experimental farm of the University of Bologna (Italy), aimed at comparing six camelina cultivars (Cypress, Midas, 789-02, Pearl, Omega, and WUR) for their agronomic and oil-compositional parameters and the SM content and composition of their seeds. Cypress was the best genotype in terms of agronomic characteristics, i.e., stable and high seed yields and increased 1000-seed weight (TKW). Pearl and 789-02 were identified as the most suitable for specific bio-based applications because of the increased n-3:n-6 ratio of the oil. Among the SM classes, PAs, and flavonols were influenced by the growing conditions and genotype. Pearl was the cultivar in which specialized metabolites were affected most by variation in meteorological conditions. Therefore, this variety may represent a starting point for future research targeting the increase/decrease of specific SM classes and the desired content of specific fatty acids by selecting the growing environment. The content and composition of camelina SMs confirm its nature as a multi-use crop, corroborating its key role in the circular economy
MYB transcription factors in Arabidopsis
No full textDubos C, Stracke R, Grotewold E, Weisshaar B, Martin C, Lepiniec L. MYB transcription factors in Arabidopsis. Trends in Plant Science. 2010;15(10):573-581
Expression analysis of flavonoid biosynthesis genes during Arabidopsis thaliana silique and seed development with a primary focus on the proanthocyanidin biosynthetic pathway
No full textKleindt CK, Stracke R, Mehrtens F, Weisshaar B. Expression analysis of flavonoid biosynthesis genes during Arabidopsis thaliana silique and seed development with a primary focus on the proanthocyanidin biosynthetic pathway. BMC Research Notes. 2010;3(1): 255.Background:
The coordinated activity of different flavonoid biosynthesis genes in Arabidopsis thaliana results in tissue-specific accumulation of flavonols, anthocyanins and proanthocyanidins (PAs). These compounds possess diverse functions in plants including light-attenuation and oxidative stress protection. Flavonoids accumulate in a stimulus- and/or development-dependent manner in specific parts of the plant. PAs accumulate in the seed coat (testa).
Findings:
We describe the biological material and the preparation of total RNA for the AtGenExpress developmental silique and seed series. AtGenExpress ATH1 GeneChip expression data from the different stages were reanalyzed and verified using quantitative real time PCR (qPCR). We observed organ-specific transcript accumulation of specific flavonoid biosynthetic genes consistent with previously published data and our PA compound accumulation data. In addition, we investigated the regulation of PA accumulation in developing A. thaliana seeds by correlating gene expression patterns of specific flavonoid biosynthesis genes with different seed embryonic developmental stages and organs and present two useful marker genes for isolated valve and replum organs, as well as one seed-specific marker.
Conclusions:
Potential caveats of array-based expression data are discussed based on comparisons with qPCR data. Results from ATH1 microarray and qPCR experiments revealed a shift in gene activity from general flavonoid biosynthesis at early stages of seed development to PA synthesis at late (mature) stages of embryogenesis. The examined PA accumulation-associated genes, including biosynthetic and regulatory genes, were found to be exclusively expressed in immature seeds. Accumulation of PAs initiates at the early heart stage of silique and seed development. Our findings provide new insights for further studies targeting the PA pathway in seeds
COMPLETE NUCLEOTIDE-SEQUENCE OF ONE MEMBER OF THE SORGHUM PHOSPHOENOLPYRUVATE CARBOXYLASE GENE FAMILY
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
THE PHOSPHOENOLPYRUVATE CARBOXYLASE GENE FAMILY OF SORGHUM - PROMOTER STRUCTURES, AMINO-ACID-SEQUENCES AND EXPRESSION OF GENES
No full textTwo different members of the phosphoenolpyruvate carboxylase(PEPC)-encoding multigene family (clones lambda-CP21 and lambda-CP46) have been isolated from a Sorghum vulgare lambda-EMBL4 genomic library. The use of the 3'-noncoding regions to probe Northern blots of RNA from roots, etiolated leaves and green leaves indicated that lambda-CP21 and lambda-CP46 encode the C3- and C4-type leaf PEPC isoforms, respectively. The lambda-CP21 clone is expressed in the three tissues and is not light-regulated, whereas lambda-CP46 is only expressed in greening leaves. The nucleotide sequence of the 5'-flanking DNA (520 bp) has been determined for both genes. For lambda-CP46, several direct repeats were located in this region with similarities to sequences found in other light-regulated genes, but not in lambda-CP21. The deduced amino acid sequences of the two S. vulgare PEPC proteins are 75% identical
Square Dancing with the Stars to Enhance Dynamic Hirschman Linkages?
No full textIn this Presidential Address, the author takes the reader on a reconnaissance of his life and time as a regional scientist. He points out scenery he found scintillating along the way, hoping that some may pick up the banner and chew on a few of the ideas for a while. He suggests a revisit to Albert O. Hirschman’s notion of key sectors and more empirical analysis related to Marcus Berliant’s and Masahisa Fujita’s notion of knowledge creation and transfer.Presidential Address, San Antonio, Texas, March 29, 2014 (53rd Meetings of the Southern Regional Science Association
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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