Degradable and Nanosegregated Elastomers with Multiblock Sequences of Biobased Aromatic Mesogens and Biofunctional Aliphatic Oligocarbonates

We have developed multiblock aromatic/aliphatic condensation polymers, comprising side-chain biofunctionalized aliphatic oligocarbonates and biobased aromatic ester triad mesogens up to 17 wt %. Nanosegregation of the aromatic mesogen-rich domains with diameters of approximately 10 nm from the soft aliphatic polymer matrix is suggested by atomic force microscopy. The polymers exhibit rubberlike properties, unlike the corresponding aliphatic polycarbonate forming viscous liquid. These properties support the interchain interactions between the aromatic mesogens, which can serve as physical cross-linking. The aromatic ester triad mesogens in the multiblock polymers significantly bolster the tolerance to organocatalytic hydrolysis and methanolysis of the polymer chains but are eventually degraded. The multiblock polymers show degradation behavior slightly faster than poly(L-lactide), whereas poly(ethylene terephthalate) remains intact under the same condition. The present study demonstrates the efficacy of aromatic ester triad mesogens incorporated into the sequences of biodegradable aliphatic polycarbonates to enhance their physical properties while retaining degradability

On the Performance Evaluation of Action Recognition Models on Transcoded Low Quality Videos

In the design of action recognition models, the quality of videos in the dataset is an important issue, however the trade-off between the quality and performance is often ignored. In general, action recognition models are trained and tested on high-quality videos, but in actual situations where action recognition models are deployed, sometimes it might not be assumed that the input videos are of high quality. In this study, we report qualitative evaluations of action recognition models for the quality degradation associated with transcoding by JPEG and H.264/AVC. Experimental results are shown for evaluating the performance of pre-trained models on the transcoded validation videos of Kinetics400. The models are also trained on the transcoded training videos. From these results, we quantitatively show the degree of degradation of the model performance with respect to the degradation of the video quality.Comment: 10 page

Metabolomic correlation-network modules in Arabidopsis based on a graph-clustering approach

<p>Abstract</p> <p>Background</p> <p>Deciphering the metabolome is essential for a better understanding of the cellular metabolism as a system. Typical metabolomics data show a few but significant correlations among metabolite levels when data sampling is repeated across individuals grown under strictly controlled conditions. Although several studies have assessed topologies in metabolomic correlation networks, it remains unclear whether highly connected metabolites in these networks have specific functions in known tissue- and/or genotype-dependent biochemical pathways.</p> <p>Results</p> <p>In our study of metabolite profiles we subjected root tissues to gas chromatography-time-of-flight/mass spectrometry (GC-TOF/MS) and used published information on the aerial parts of 3 <it>Arabidopsis </it>genotypes, Col-0 wild-type, <it>methionine over-accumulation 1 </it>(<it>mto1</it>), and <it>transparent testa4 </it>(<it>tt4</it>) to compare systematically the metabolomic correlations in samples of roots and aerial parts. We then applied graph clustering to the constructed correlation networks to extract densely connected metabolites and evaluated the clusters by biochemical-pathway enrichment analysis. We found that the number of significant correlations varied by tissue and genotype and that the obtained clusters were significantly enriched for metabolites included in biochemical pathways.</p> <p>Conclusions</p> <p>We demonstrate that the graph-clustering approach identifies tissue- and/or genotype-dependent metabolomic clusters related to the biochemical pathway. Metabolomic correlations complement information about changes in mean metabolite levels and may help to elucidate the organization of metabolically functional modules.</p

Organocatalytic depolymerization of poly(trimethylene carbonate)

Aliphatic polycarbonates have attracted attention as degradable and sustainable materials contributing to the circular plastic economy. Their chemical recycling has not been sufficiently studied. In this study, the efficacy of organocatalysts for depolymerization of poly(trimethylene carbonate) (PTMC), a representative aliphatic polycarbonate, is investigated using several organic acids and bases. The hydrolysis of PTMC produces the water-soluble degradates propane-1,3-diol (PD) and CO2. A phosphazene base P2-t-Bu shows high activity for the hydrolysis, yielding up to 31% and 89% of PD in the homogeneous reaction at around 27°C and the inhomogeneous reaction under the reflux condition, respectively. By contrast, 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) exhibits exceptionally high catalytic activity for the methanolysis of PTMC, producing PD and dimethyl carbonate. This is because of dual hydrogen-bonding activation, which completes the inhomogeneous reaction in a few hours at around 27°C while yielding more than 90% of PD. The reaction rate of the TBD-catalyzed methanolysis depends on the concentration of the nucleophile and catalyst, and the ratio of the nucleophile to the substrate affects the PD yield. These results provide a highly promising standard for chemical recycling of functionalized aliphatic polycarbonates that could potentially be applied to sustainable materials in the future

Unbiased characterization of genotype-dependent metabolic regulations by metabolomic approach in Arabidopsis thaliana

<p>Abstract</p> <p>Background</p> <p>Metabolites are not only the catalytic products of enzymatic reactions but also the active regulators or the ultimate phenotype of metabolic homeostasis in highly complex cellular processes. The modes of regulation at the metabolome level can be revealed by metabolic networks. We investigated the metabolic network between wild-type and 2 mutant (<it>methionine-over accumulation 1 </it>[<it>mto1</it>] and <it>transparent testa4 </it>[<it>tt4</it>]) plants regarding the alteration of metabolite accumulation in <it>Arabidopsis thaliana</it>.</p> <p>Results</p> <p>In the GC-TOF/MS analysis, we acquired quantitative information regarding over 170 metabolites, which has been analyzed by a novel score (ZMC, z-score of metabolite correlation) describing a characteristic metabolite in terms of correlation. Although the 2 mutants revealed no apparent morphological abnormalities, the overall correlation values in <it>mto1 </it>were much lower than those of the wild-type and <it>tt4 </it>plants, indicating the loss of overall network stability due to the uncontrolled accumulation of methionine. In the <it>tt4 </it>mutant, a new correlation between malate and sinapate was observed although the levels of malate, sinapate, and sinapoylmalate remain unchanged, suggesting an adaptive reconfiguration of the network. Gene-expression correlations presumably responsible for these metabolic networks were determined using the metabolite correlations as clues.</p> <p>Conclusion</p> <p>Two Arabidopsis mutants, <it>mto1 </it>and <it>tt4</it>, exhibited the following changes in entire metabolome networks: the overall loss of metabolic stability (<it>mto1</it>) or the generation of a metabolic network of a backup pathway for the lost physiological functions (<it>tt4</it>). The expansion of metabolite correlation to gene-expression correlation provides detailed insights into the systemic understanding of the plant cellular process regarding metabolome and transcriptome.</p

Organic carboxylate salt-enabled alternative synthetic routes for bio-functional cyclic carbonates and aliphatic polycarbonates

Simple and efficient synthetic routes for functionalized cyclic carbonates are indispensable for the practical application of side-chain bio-functionalized aliphatic polycarbonates as biodegradable functional biomaterials. In this study, a six-membered cyclic carbonate with a triethylammonium carboxylate has been prepared in one step from 2,2-bis(methylol)propionic acid (bis-MPA). We have demonstrated the suitability of the organic carboxylate salt of the bis-MPA cyclic carbonate for esterification with alkyl bromides via the SN2 mechanism, leading to the formation of functionalized cyclic carbonate monomers. The esterification of the organic carboxylate salt proceeds efficiently when alkyl bromides with α-carbonyl, allyl, and benzyl groups are used. This approach enables a two-step synthesis of functionalized cyclic carbonates from bis-MPA. The organocatalyzed ring-opening polymerization of the resultant functionalized cyclic carbonates is effectively controlled, indicating that the synthetic process involving the organic carboxylate salt does not influence their polymerizability. The ether-functionalized aliphatic polycarbonates obtained from the organic carboxylate salt exhibit good antiplatelet properties, comparable to those of a previously developed blood-compatible aliphatic polycarbonate. The synthetic pathways exploiting organic carboxylate salts enable alternative shortcuts to functionalized cyclic carbonates from bis-MPA

A Systems Analysis With “Simplified Source-Sink Model” Reveals Metabolic Reprogramming in a Pair of Source-to-Sink Organs During Early Fruit Development in Tomato by LED Light Treatments

Tomato (Solanum lycopersicum) is a model crop for studying development regulation and ripening in flesh fruits and vegetables. Supplementary light to maintain the optimal light environment can lead to the stable growth of tomatoes in greenhouses and areas without sufficient daily light integral. Technological advances in genome-wide molecular phenotyping have dramatically enhanced our understanding of metabolic shifts in the plant metabolism across tomato fruit development. However, comprehensive metabolic and transcriptional behaviors along the developmental process under supplementary light provided by light-emitting diodes (LEDs) remain to be fully elucidated. We present integrative omic approaches to identify the impact on the metabolism of a single tomato plant leaf exposed to monochromatic red LEDs of different intensities during the fruit development stage. Our special light delivery system, the “simplified source-sink model,” involves the exposure of a single leaf below the second truss to red LED light of different intensities. We evaluated fruit-size- and fruit-shape variations elicited by different light intensities. Our findings suggest that more than high-light treatment (500 μmol m-2 s-1) with the red LED light is required to accelerate fruit growth for 2 weeks after anthesis. To investigate transcriptomic and metabolomic changes in leaf- and fruit samples we used microarray-, RNA sequencing-, and gas chromatography-mass spectrometry techniques. We found that metabolic shifts in the carbohydrate metabolism and in several key pathways contributed to fruit development, including ripening and cell-wall modification. Our findings suggest that the proposed workflow aids in the identification of key metabolites in the central metabolism that respond to monochromatic red-LED treatment and contribute to increase the fruit size of tomato plants. This study expands our understanding of systems-level responses mediated by low-, appropriate-, and high levels of red light irradiation in the fruit growth of tomato plants

Effects of Combined Low Glutathione with Mild Oxidative and Low Phosphorus Stress on the Metabolism of Arabidopsis thaliana

Plants possess highly sensitive mechanisms that monitor environmental stress levels for a dose-dependent fine-tuning of their growth and development. Differences in plant responses to severe and mild abiotic stresses have been recognized. Although many studies have revealed that glutathione can contribute to plant tolerance to various environmental stresses, little is known about the relationship between glutathione and mild abiotic stress, especially the effect of stress-induced altered glutathione levels on the metabolism. Here, we applied a systems biology approach to identify key pathways involved in the gene-to-metabolite networks perturbed by low glutathione content under mild abiotic stress in Arabidopsis thaliana. We used glutathione synthesis mutants (cad2-1 and pad2-1) and plants overexpressing the gene encoding γ-glutamylcysteine synthetase, the first enzyme of the glutathione biosynthetic pathway. The plants were exposed to two mild stress conditions—oxidative stress elicited by methyl viologen and stress induced by the limited availability of phosphate. We observed that the mutants and transgenic plants showed similar shoot growth as that of the wild-type plants under mild abiotic stress. We then selected the synthesis mutants and performed multi-platform metabolomics and microarray experiments to evaluate the possible effects on the overall metabolome and the transcriptome. As a common oxidative stress response, several flavonoids that we assessed showed overaccumulation, whereas the mild phosphate stress resulted in increased levels of specific kaempferol- and quercetin-glycosides. Remarkably, in addition to a significant increased level of sugar, osmolytes, and lipids as mild oxidative stress-responsive metabolites, short-chain aliphatic glucosinolates over-accumulated in the mutants, whereas the level of long-chain aliphatic glucosinolates and specific lipids decreased. Coordinated gene expressions related to glucosinolate and flavonoid biosynthesis also supported the metabolite responses in the pad2-1 mutant. Our results suggest that glutathione synthesis mutants accelerate transcriptional regulatory networks to control the biosynthetic pathways involved in glutathione-independent scavenging metabolites, and that they might reconfigure the metabolic networks in primary and secondary metabolism, including lipids, glucosinolates, and flavonoids. This work provides a basis for the elucidation of the molecular mechanisms involved in the metabolic and transcriptional regulatory networks in response to combined low glutathione content with mild oxidative and nutrient stress in A. thaliana

Metabolic Reprogramming in Leaf Lettuce Grown Under Different Light Quality and Intensity Conditions Using Narrow-Band LEDs

Light-emitting diodes (LEDs) are an artificial light source used in closed-type plant factories and provide a promising solution for a year-round supply of green leafy vegetables, such as lettuce (Lactuca sativa L.). Obtaining high-quality seedlings using controlled irradiation from LEDs is critical, as the seedling health affects the growth and yield of leaf lettuce after transplantation. Because key molecular pathways underlying plant responses to a specific light quality and intensity remain poorly characterised, we used a multi-omics–based approach to evaluate the metabolic and transcriptional reprogramming of leaf lettuce seedlings grown under narrow-band LED lighting. Four types of monochromatic LEDs (one blue, two green and one red) and white fluorescent light (control) were used at low and high intensities (100 and 300 μmol·m−2·s−1, respectively). Multi-platform mass spectrometry-based metabolomics and RNA-Seq were used to determine changes in the metabolome and transcriptome of lettuce plants in response to different light qualities and intensities. Metabolic pathway analysis revealed distinct regulatory mechanisms involved in flavonoid and phenylpropanoid biosynthetic pathways under blue and green wavelengths. Taken together, these data suggest that the energy transmitted by green light is effective in creating a balance between biomass production and the production of secondary metabolites involved in plant defence

ゾル−ゲル転移を示す生体適合ポリマー材料の開発と応用 (2)

(1) Title: Bulk pH Responsive DNA Quadruplex Hydrogels Prepared by Liquid-Phase Large Scale DNA SynthesisJournal: ACS Macro Letters(2) Title: Communication—DNA Quadruplex Hydrogel Beads Showing Peroxidase ActivityJournal: Journal of The Electrochemical SocietyDOI: http://dx.doi.org/10.1149/2.0441909je