Functional characterization of long-chain prenyl diphosphate synthases from tomato

2013 ◽  
Vol 449 (3) ◽  
pp. 729-740 ◽  
Author(s):  
Matthew O. Jones ◽  
Laura Perez-Fons ◽  
Francesca P. Robertson ◽  
Peter M. Bramley ◽  
Paul D. Fraser
Keyword(s):  
Functional Characterization ◽  
Primary Metabolism ◽  
Virus Induced Gene Silencing ◽  
In Planta ◽  
Constitutive Overexpression ◽  
Prenyl Diphosphate ◽  
And Function ◽  
Leaf Appearance ◽  
Long Chain

The electron transfer molecules plastoquinone and ubiquinone are formed by the condensation of aromatic head groups with long-chain prenyl diphosphates. In the present paper we report the cloning and characterization of two genes from tomato (Solanum lycopersicum) responsible for the production of solanesyl and decaprenyl diphosphates. SlSPS (S. lycopersicum solanesyl diphosphate synthase) is targeted to the plastid and both solanesol and plastoquinone are associated with thylakoid membranes. A second gene [SlDPS (S. lycopersicum solanesyl decaprenyl diphosphate synthase)], encodes a long-chain prenyl diphosphate synthase with a different subcellular localization from SlSPS and can utilize geranyl, farnesyl or geranylgeranyl diphosphates in the synthesis of C45 and C50 prenyl diphosphates. When expressed in Escherichia coli, SlSPS and SlDPS extend the prenyl chain length of the endogenous ubiquinone to nine and ten isoprene units respectively. In planta, constitutive overexpression of SlSPS elevated the plastoquinone content of immature tobacco leaves. Virus-induced gene silencing showed that SlSPS is necessary for normal chloroplast structure and function. Plants silenced for SlSPS were photobleached and accumulated phytoene, whereas silencing SlDPS did not affect leaf appearance, but impacted on primary metabolism. The two genes were not able to complement silencing of each other. These findings indicate a requirement for two long-chain prenyl diphosphate synthases in the tomato.

Functional characterization of human brown adipose tissue metabolism

2020 ◽  
Vol 477 (7) ◽  
pp. 1261-1286 ◽  
Author(s):  
Marie Anne Richard ◽  
Hannah Pallubinsky ◽  
Denis P. Blondin
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Functional Characterization ◽  
Human Infants ◽  
Positron Emission ◽  
Brown Adipose ◽  
Treatment Of Obesity ◽  
And Function

Brown adipose tissue (BAT) has long been described according to its histological features as a multilocular, lipid-containing tissue, light brown in color, that is also responsive to the cold and found especially in hibernating mammals and human infants. Its presence in both hibernators and human infants, combined with its function as a heat-generating organ, raised many questions about its role in humans. Early characterizations of the tissue in humans focused on its progressive atrophy with age and its apparent importance for cold-exposed workers. However, the use of positron emission tomography (PET) with the glucose tracer [18F]fluorodeoxyglucose ([18F]FDG) made it possible to begin characterizing the possible function of BAT in adult humans, and whether it could play a role in the prevention or treatment of obesity and type 2 diabetes (T2D). This review focuses on the in vivo functional characterization of human BAT, the methodological approaches applied to examine these features and addresses critical gaps that remain in moving the field forward. Specifically, we describe the anatomical and biomolecular features of human BAT, the modalities and applications of non-invasive tools such as PET and magnetic resonance imaging coupled with spectroscopy (MRI/MRS) to study BAT morphology and function in vivo, and finally describe the functional characteristics of human BAT that have only been possible through the development and application of such tools.

Functional characterization of the trypanosome translational repressor SCD6

2013 ◽  
Vol 457 (1) ◽  
pp. 57-67 ◽  
Author(s):  
Marina Cristodero ◽  
Bernd Schimanski ◽  
Manfred Heller ◽  
Isabel Roditi
Keyword(s):  
Functional Characterization ◽  
Stress Granule ◽  
Granule Formation ◽  
Translational Repressor ◽  
And Function

Trypanosomal SCD6 is a general repressor of translation. It is not required for stress granule formation and, unusually, does not interact with the helicase DHH1. We analysed domains involved in the localization and function of TbSCD6 and identified interacting partners.

scholarly journals A Quantitative System-Scale Characterization of the Metabolism of Clostridium acetobutylicum

mBio ◽  
2015 ◽  
Vol 6 (6) ◽  
Author(s):  
Minyeong Yoo ◽  
Gwenaelle Bestel-Corre ◽  
Christian Croux ◽  
Antoine Riviere ◽  
Isabelle Meynial-Salles ◽  
...  
Keyword(s):  
Steady State ◽  
Metabolic Engineering ◽  
Clostridium Acetobutylicum ◽  
Functional Characterization ◽  
Scale Model ◽  
Primary Metabolism ◽  
Scale Analysis ◽  
Content Type ◽  
Commercial Process

ABSTRACTEngineering industrial microorganisms for ambitious applications, for example, the production of second-generation biofuels such as butanol, is impeded by a lack of knowledge of primary metabolism and its regulation. A quantitative system-scale analysis was applied to the biofuel-producing bacteriumClostridium acetobutylicum, a microorganism used for the industrial production of solvent. An improved genome-scale model,iCac967, was first developed based on thorough biochemical characterizations of 15 key metabolic enzymes and on extensive literature analysis to acquire accurate fluxomic data. In parallel, quantitative transcriptomic and proteomic analyses were performed to assess the number of mRNA molecules per cell for all genes under acidogenic, solventogenic, and alcohologenic steady-state conditions as well as the number of cytosolic protein molecules per cell for approximately 700 genes under at least one of the three steady-state conditions. A complete fluxomic, transcriptomic, and proteomic analysis applied to different metabolic states allowed us to better understand the regulation of primary metabolism. Moreover, this analysis enabled the functional characterization of numerous enzymes involved in primary metabolism, including (i) the enzymes involved in the two different butanol pathways and their cofactor specificities, (ii) the primary hydrogenase and its redox partner, (iii) the major butyryl coenzyme A (butyryl-CoA) dehydrogenase, and (iv) the major glyceraldehyde-3-phosphate dehydrogenase. This study provides important information for further metabolic engineering ofC. acetobutylicumto develop a commercial process for the production ofn-butanol.IMPORTANCECurrently, there is a resurgence of interest inClostridium acetobutylicum, the biocatalyst of the historical Weizmann process, to producen-butanol for use both as a bulk chemical and as a renewable alternative transportation fuel. To develop a commercial process for the production ofn-butanol via a metabolic engineering approach, it is necessary to better characterize both the primary metabolism ofC. acetobutylicumand its regulation. Here, we apply a quantitative system-scale analysis to acidogenic, solventogenic, and alcohologenic steady-stateC. acetobutylicumcells and report for the first time quantitative transcriptomic, proteomic, and fluxomic data. This approach allows for a better understanding of the regulation of primary metabolism and for the functional characterization of numerous enzymes involved in primary metabolism.

scholarly journals Ontogenic, phenotypic, and functional characterization of XCR1+ dendritic cells leads to a consistent classification of intestinal dendritic cells based on the expression of XCR1 and SIRPα

2014 ◽  
Author(s):  
Martina Becker ◽  
Steffen Güttler ◽  
Annabell Bachem ◽  
Evelyn Hartung ◽  
Ahmed Mora ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
T Cell ◽  
Functional Characterization ◽  
Cross Presentation ◽  
Intestinal Immune System ◽  
Lineage Marker ◽  
And Function ◽  
First Time

In the past, lack of lineage markers confounded the classification of dendritic cells (DC) in the intestine and impeded a full understanding of their location and function. We have recently shown that the chemokine receptor XCR1 is a lineage marker for cross-presenting DC in the spleen. Now we provide evidence that intestinal XCR1+ DC largely, but not fully, overlap with CD103+ CD11b- DC, the hypothesized correlate of “cross-presenting DC” in the intestine, and are selectively dependent in their development on the transcription factor Batf3. XCR1+ DC are located in the villi and epithelial crypts of the lamina propria of the small intestine, the T cell zones of Peyer’s Patches, and in the T cell zones and sinuses of the draining mesenteric lymph node. Functionally, we could demonstrate for the first time that XCR1+ / CD103+ CD11b- DC excel in the cross-presentation of orally applied antigen. Together, our data show that XCR1 is a lineage marker for cross-presenting DC also in the intestinal immune system. Further, extensive phenotypic analyses reveal that expression of the integrin SIRPα consistently demarcates the XCR1- DC population. We propose a simplified and consistent classification system for intestinal DC based on the expression of XCR1 and SIRPα.

scholarly journals Virus-Induced Gene Silencing-Based Functional Characterization of Genes Associated with Powdery Mildew Resistance in Barley

2005 ◽  
Vol 138 (4) ◽  
pp. 2155-2164 ◽  
Author(s):  
Ingo Hein ◽  
Maria Barciszewska-Pacak ◽  
Katarina Hrubikova ◽  
Sandie Williamson ◽  
Malene Dinesen ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Gene Silencing ◽  
Powdery Mildew Resistance ◽  
Functional Characterization ◽  
Virus Induced Gene Silencing ◽  
Mildew Resistance

Isolation and characterization of a cDNA encoding a Δ8 sphingolipid desaturase from Aquilegia vulgaris

2002 ◽  
Vol 30 (6) ◽  
pp. 1073-1075 ◽  
Author(s):  
L. V. Michaelson ◽  
A. J. Longman ◽  
O. Sayanova ◽  
A. K. Stobart ◽  
J. A. Napier
Keyword(s):  
Functional Characterization ◽  
Yeast Cells ◽  
Sphingoid Bases ◽  
Yeast Saccharomyces Cerevisiae ◽  
Isolation And Characterization ◽  
Long Chain Base ◽  
In The Wild ◽  
Cis And Trans ◽  
Long Chain

We have isolated a cDNA encoding the Δ8 sphingolipid desaturase from the plant Aquilegia vulgaris L. via a PCR-based strategy using primers designed to target the conserved histidine box regions of microsomal desaturases. The function of the cDNA was confirmed by expression in the yeast, Saccharomyces cerevisiae. Analysis of the long-chain sphingoid bases as their dinitrophenyl derivatives by reverse-phase HPLC demonstrated the accumulation of cis- and trans-desaturated sphingoid bases which were not present in the wild-type yeast cells. The Δ8 desaturated products co-eluted with known Δ8-desaturated phytosphingenine and the molecular mass of these products was confirmed by liquid chromatography-MS. The Δ8 long-chain base desaturase was also able to desaturate dihydrosphingosine substrates. This is the first report of the functional characterization of an A. vulgaris gene product.

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