New Insights Into Sunflower (Helianthus annuus L.) FatA and FatB Thioesterases, Their Regulation, Structure and Distribution

Sunflower seeds (Helianthus annuus L.) accumulate large quantities of triacylglycerols (TAG) between 12 and 28 days after flowering (DAF). This is the period of maximal acyl-acyl carrier protein (acyl-ACP) thioesterase activity in vitro, the enzymes that terminate the process of de novo fatty acid synthesis by catalyzing the hydrolysis of the acyl-ACPs synthesized by fatty acid synthase. Fatty acid thioesterases can be classified into two families with distinct substrate specificities, namely FatA and FatB. Here, some new aspects of these enzymes have been studied, assessing how both enzymes contribute to the acyl composition of sunflower oil, not least through the changes in their expression during the process of seed filling. Moreover, the binding pockets of these enzymes were modeled based on new data from plant thioesterases, revealing important differences in their volume and geometry. Finally, the subcellular location of the two enzymes was evaluated and while both possess an N-terminal plastid transit peptide, only in FatB contains a hydrophobic sequence that could potentially serve as a transmembrane domain. Indeed, using in vivo imaging and organelle fractionation, H. annuus thioesterases, HaFatA and HaFatB, appear to be differentially localized in the plastid stroma and membrane envelope, respectively. The divergent roles fulfilled by HaFatA and HaFatB in oil biosynthesis are discussed in the light of our data.España MINECO y FEDER Projects AGL2014- 53537-R y AGL2017-83449-

Molecular and biochemical characterization of hydroxyjasmonate and flavonoid sulfotransferases from Arabidopsis thaliana

Recently, we initiated a functional genomics project with the objective of characterizing the biological function of all the sulfotransferase (ST) coding genes of A. thaliana . Based on amino acid sequence alignment with previously characterized soluble STs, we have identified 17 genes coding for putative STs in the genome of this plant. Prior to this work, only one ST-coding gene ( AtST1 ) has been characterized from A. thaliana . AtST1 was shown to sulfonate brassinosteroids and was proposed to be involved in the modulation of their biological activity. This thesis presents the characterization of two more ST-coding genes from A. thaliana , namely AtST2a and AtST3a . The recombinant AtST3a protein was found to exhibit strict specificity for position 7 of flavonoids. In contrast with the previously characterized flavonol 7-ST from Flaveria bidentis that sulfonates only flavonol disulfates, AtST3a was found to accept a number of flavonols and flavone aglycones, as well as their monosulfate derivatives. The AtST3a is expressed only at the earlier stage of seedling development. In contrast, the expression pattern of the flavonol 3-ST from Flaveria species is detectable at all stages of plant development, with highest activities found in the terminal buds and first pair of leaves. The natural occurrence of a ST exhibiting high specificity for flavonoids in A. thaliana suggests that sulfated flavonoids may be of more common occurrence in the plant kingdom than once thought. In this study, we demonstrate that the AtST2a from A. thaliana encodes a sulfotransferase specific for 11- and 12-hydroxyjasmonic acid. Jasmonic acid and its derivatives, commonly named jasmonates, are of ubiquitous occurrence in the plant kingdom and they play an important role in the plant response to biotic and abiotic stresses. More recently, it has been demonstrated that jasmonates are also involved in the control of key developmental processes such as anther development. AtST2a is not expressed in plants growing in the light but is induced 8 hours after their transfer to the dark. Overexpression of AtST2a in transgenic Arabidopsis leads to a delayed flowering phenotype observed only when the plants are growing under long-days. In contrast, decreasing AtST2a expression by expressing antisense AtST2a RNA leads to an early flowering phenotype observed only in short day-grown transgenic plants. Our results suggest that the function of AtST2a is to sulfonate hydroxylated jasmonic acids under growth conditions that do not favor flowering. This data also suggest that hydroxylated jasmonic acids act as signals that promote the transition from vegetative to reproductive growth when A. thaliana is exposed to an inductive photoperiod

Passive volatilization behaviour of gasoline in unsaturated soils

Gasoline contamination of soil can present a health and explosion risk. This risk will be determined by the gasoline's ability to migrate in the soil; one important mechanism in soil is volatilization. To describe passive volatilization behaviour of gasoline in unsaturated soils, laboratory experiments using synthetic gasoline and acrylic columns were conducted. Objectives were to monitor gasoline component behaviour as a function of depth and time at different water contents and temperatures. Gasoline volatilization behaviour was heavily influenced by immiscible phase capillary rise (wicking). Wicking was sufficiently important that surface gasoline concentrations could be higher than average column concentrations. Solidification of low molecular weight components at the soil surface was responsible for this accumulation. Water content had a non-linear effect on wicking, but the initial gasoline content was the most important wicking factor. Subzero temperatures slowed wicking, and allowed immiscible phase movement to continue for longer periods of time

Localization of the Carnation Italian ringspot virus replication protein p36 to the mitochondrial outer membrane is mediated by an internal targeting signal and the TOM complex

<p>Abstract</p> <p>Background</p> <p><it>Carnation Italian ringspot virus </it>(CIRV) is a positive-strand RNA virus that causes massive structural alterations of mitochondria in infected host cells, the most conspicuous being the formation of numerous internal vesicles/spherules that are derived from the mitochondrial outer membrane and serve as the sites for viral RNA replication. While the membrane-bound components of the CIRV replication complex, including a 36-kD RNA-binding protein (p36), are known to be essential for these changes in mitochondrial morphology and are relatively well characterized in terms of their roles in nascent viral RNA synthesis, how these proteins are specifically targeted and inserted into mitochondria is poorly defined.</p> <p>Results</p> <p>Here we report on the molecular signal responsible for sorting p36 to the mitochondrial outer membrane. Using a combination of gain-of-function assays with portions of p36 fused to reporter proteins and domain-swapping assays with p36 and another closely-related viral RNA-binding protein, p33, that sorts specifically to the peroxisomal boundary membrane, we show that the mitochondrial targeting information in p36 resides within its two transmembrane domains (TMDs) and intervening hydrophilic loop sequence. Comprehensive mutational analysis of these regions in p36 revealed that the primary targeting determinants are the moderate hydrophobicity of both TMDs and the positively-charged face of an amphipathic helix within the intervening loop sequence. We show also using bimolecular fluorescence complementation (BiFC) that p36 interacts with certain components of the translocase complex in the mitochondrial outer membrane (TOM), but not with the sorting and assembly machinery (SAM).</p> <p>Conclusion</p> <p>Our results provide insight to how viruses, such as CIRV, exploit specific host-cell protein sorting pathways to facilitate their replication. The characterization of the targeting and insertion of p36 into the mitochondrial outer membrane also sheds light on the mechanisms involved in sorting of host-cell membrane proteins to mitochondria, a process that has been largely unexplored in plants.</p

Deglutitive Inhibition, Latency Between Swallow and Esophageal Contractions and Primary Esophageal Motor Disorders

Swallowing induces an inhibitory wave that is followed by a contractile wave along the esophageal body. Deglutitive inhibition in the skeletal muscle of the esophagus is controlled in the brain stem whilst in the smooth muscle, an intrinsic peripheral control mechanism is critical. The latency between swallow and contractions is determined by the pattern of activation of the inhibitory and excitatory vagal pathways, the regional gradients of inhibitory and excitatory myenteric nerves, and the intrinsic properties of the smooth muscle. A wave of inhibition precedes a swallow-induced peristaltic contraction in the smooth muscle part of the human oesophagus involving both circular and longitudinal muscles in a peristaltic fashion. Deglutitive inhibition is necessary for drinking liquids which requires multiple rapid swallows (MRS). During MRS the esophageal body remains inhibited until the last of the series of swallows and then a peristaltic contraction wave follows. A normal response to MRS requires indemnity of both inhibitory and excitatory mechanisms and esophageal muscle. MRS has recently been used to assess deglutitive inhibition in patients with esophageal motor disorders. Examples with impairment of deglutitive inhibition are achalasia of the LES and diffuse esophageal spasm

An integrated omics analysis reveals molecular mechanisms that are associated with differences in seed oil content between Glycine max and Brassica napus

Abstract Background: Rapeseed (Brassica napus L.) and soybean (Glycine max L.) seeds are rich in both protein and oil, which are major sources of biofuels and nutrition. Although the difference in seed oil content between soybean (~ 20%) and rapeseed (~ 40%) exists, little is known about its underlying molecular mechanism. Results: An integrated omics analysis was performed in soybean, rapeseed, Arabidopsis (Arabidopsis thaliana L. Heynh), and sesame (Sesamum indicum L.), based on Arabidopsis acyl-lipid metabolism- and carbon metabolism-related genes. As a result, candidate genes and their transcription factors and microRNAs, along with phylogenetic analysis and co-expression network analysis of the PEPC gene family, were found to be largely associated with the difference between the two species. First, three soybean genes (Glyma.13G148600, Glyma.13G207900 and Glyma.12G122900) co-expressed with GmPEPC1 are specifically enriched during seed storage protein accumulation stages, while the expression of BnPEPC1 is putatively inhibited by bna-miR169, and two genes BnSTKA and BnCKII are co-expressed with BnPEPC1 and are specifically associated with plant circadian rhythm, which are related to seed oil biosynthesis. Then, in de novo fatty acid synthesis there are rapeseed-specific genes encoding subunits β-CT (BnaC05g37990D) and BCCP1 (BnaA03g06000D) of heterogeneous ACCase, which could interfere with synthesis rate, and β-CT is positively regulated by four transcription factors (BnaA01g37250D, BnaA02g26190D, BnaC01g01040D and BnaC07g21470D). In triglyceride synthesis, GmLPAAT2 is putatively inhibited by three miRNAs (gma-miR171, gma-miR1516 and gma-miR5775). Finally, in rapeseed there was evidence for the expansion of gene families, CALO, OBO and STERO, related to lipid storage, and the contraction of gene families, LOX, LAH and HSI2, related to oil degradation. Conclusions: The molecular mechanisms associated with differences in seed oil content provide the basis for future breeding efforts to improve seed oil content

Design Development and Analysis Of Two Wheeler Eco Friendly Plastic Carburetor With Rapid Prototyping

The design development and analysis of carburetor has been carry out by applying structural and thermal loads. The present work particularly deals with the drafting and designing of carburetor using plastic materials which can be manufactured with rapid prototyping to increase mass production. My main aim is to prevent the component from getting corroded or undergoing corrosion. Replacing metal components with plastic ones can offer some important bondage. Unlike metals, plastic materials can be modified to better suit. And also manufactured by using RP technique the life of the product increases of course when fuel injectors are replaced it as the main fuel input system, it had evolve into a complicated, sophisticated, expensive system. Carburetors are still found on automobiles, many small engines like those on lawn movers and model airplanes still use carburetors. It is to keep the cost of the engine down and it is very cheap to manufacture while fuel injectors requires more costly control systems

Protein–Protein Interaction Network and Subcellular Localization of the Arabidopsis Thaliana ESCRT Machinery

The endosomal sorting complex required for transport (ESCRT) consists of several multi-protein subcomplexes which assemble sequentially at the endosomal surface and function in multivesicular body (MVB) biogenesis. While ESCRT has been relatively well characterized in yeasts and mammals, comparably little is known about ESCRT in plants. Here we explored the yeast two-hybrid protein interaction network and subcellular localization of the Arabidopsis thaliana ESCRT machinery. We show that the Arabidopsis ESCRT interactome possesses a number of protein–protein interactions that are either conserved in yeasts and mammals or distinct to plants. We show also that most of the Arabidopsis ESCRT proteins examined at least partially localize to MVBs in plant cells when ectopically expressed on their own or co-expressed with other interacting ESCRT proteins, and some also induce abnormal MVB phenotypes, consistent with their proposed functional role(s) as part of the ESCRT machinery in Arabidopsis. Overall, our results help define the plant ESCRT machinery by highlighting both conserved and unique features when compared to ESCRT in other evolutionarily diverse organisms, providing a foundation for further exploration of ESCRT in plants