bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cell Wall Polysaccharide Composition and Covalent Crosslinking
Authors: Fry Stephen C. 
Published: May 2017

Abstract

Genetics now potentially lets us modify the production, crosslinking and degradation of cell wall polysaccharides. There remains, however, the need to test experimentally whether intended modifications of polysaccharide metabolism have successfully been effected
in vivo
. Simple methods for this are described, including
in‐vivo
radiolabelling, enzymic dissection (e.g. with Driselase) and chromatographic/electrophoretic fractionation of dissection products.

After an overview of polysaccharide chemistry, I discuss the structures and taxonomic distribution of wall polysaccharides in charophytes and land plants. Primary and secondary walls are compared.

The major wall polysaccharides are cellulose [microfibrillar β‐(1→4)‐
d
‐glucan], pectins (α‐
d
‐galacturonate‐rich) and hemicelluloses (lacking galacturonate; hydrogen‐bonding to cellulose; extractable by 6 M NaOH at 37 °C). Land‐plant pectins are anionic polymers built of about four glycosidically interconnected domains (homogalacturonan, rhamnogalacturonans I and II, xylogalacturonan). Hemicelluloses occurring in most/all land plants are α‐xylo‐β‐glucans, β‐xylans (including α‐arabino‐β‐xylans, α‐glucurono‐β‐xylans, etc.) and β‐mannans (including α‐galacto‐β‐mannans, β‐gluco‐β‐mannans, etc.). Another hemicellulose [mixed‐linkage β‐(1→3)(1→4)‐
d
‐glucan) is confined to
Equisetum
and some Poales.

Other taxonomically restricted features of angiosperm primary walls occur in Poales (xylose‐poor xyloglucans; feruloylated arabinoxylans); Solanales and Lamiales (characteristic xyloglucans); Caryophyllales (feruloylated pectins); and Alismatales (apiogalacturonan). I also summarize characteristic wall features of charophytes, bryophytes, lycopodiophytes, fern‐allies and gymnosperms.
The making or breaking of a ‘crosslink’ (defined as an individual chemical bond, not a whole ‘tethering’ chain) may cause wall tightening/loosening. Covalent crosslinks include phenolic coupling products, uronoyl esters and amides, and borate diesters.
Approaches to Chemical Synthesis of Pectic Oligosaccharides
Authors: Nepogodiev Sergey A. , Field Robert A. , Damager Iben 
Published: May 2017

AbstractMany aspects of pectin biosynthesis and the physical properties of pectic polysaccharides can be better understood with the aid of small, well‐defined oligosaccharide fragments of these macromolecules. Synthetic chemists have contributed to the study of pectin by preparation of fragments representing all three major types of pectic polysaccharide: homogalacturonan (HG), rhamnogalacturonan‐I (RG‐I) and rhamnogalacturonan‐II (RG‐II). Such molecules have been synthesized by sequential coupling of building blocks, the so‐called glycosyl donors (GD) and glycosyl acceptors (GA), which aimed at the formation of specific glycosidic linkages as they are present in the target oligosaccharides. Challenges in synthesis of pectic oligosaccharides are associated with often poor stereoselectivity of glycosylation reactions between GA and GD, in particular for the construction of 1,2‐cis‐glycosidic linkages, high degrees of branching of oligosaccharide chains of target molecules and the nature of many monosaccharide components of pectin, which are often acidic and sometimes rare branched‐chain sugars. Preparation of carbohydrate building blocks, includingde novosyntheses of unusual sugars, protecting group strategies for GA and GD, glycosylation methodologies and general strategies for oligosaccharide assembly are described with the focus on pectin fragments. Synthetic routes to fragments of each type of pectic polysaccharides are discussed in detail in separate sections and structures of all currently known synthetic pectin fragments are summarized. The unsolved problems and future prospects for improved access to synthetic pectin fragments are also discussed.
Annotating Carbohydrate‐Active Enzymes in Plant Genomes: Present Challenges
Authors: Coutinho Pedro M. , Henrissat Bernard 
Published: May 2017

Abstract

There are far more carbohydrate structures than protein folds and, not unexpectedly, sequence‐based families of carbohydrate‐active enzymes often group together enzymes of different specificity. While this fact illustrates the remarkable plasticity of proteins to evolve novel specificities from pre‐existing folds, this is also the source of potential errors during the functional prediction of genes derived from whole genome sequencing efforts. This chapter reviews the problems and the advances associated with the sequence‐based classification of plant carbohydrate‐active enzymes as used in the CAZy database (
www.cazy.org
).
Genes and Enzymes of theGT31Family: Towards Unravelling The Function(s) of the Plant Glycosyltransferase Family Members
Authors: Egelund Jack , Ellis Miriam , Doblin Monika , Qu Yongmei , Bacic Antony 
Published: May 2017

AbstractThe galactosyltransferases (GalTs) have been extensively studied in mammals where they are involved in the synthesis of bothN‐ andO‐glycans on glycoproteins. In contrast, only a few studies have been published characterizing plant GalTs even though plants assemble many complex carbohydrates and glycoconjugates not found in other eukaryotes or bacteria, such as pectins, galactomannans, xyloglucans, arabinogalactan‐proteins (AGPs), proline‐rich proteins and extensins. Many enzymes characterized within family GT31 are mammalian and include the fringe proteins (GlcNAc‐β‐(1,3)‐Fuc), the chondroitin synthases (GlcUA‐β‐(1,3)‐GalNAc), and the β‐(1,3)‐GalTs. We attempted to categorize the putative β‐(1,3)‐GalTs and, where possible, we predicted their putative substrate specificity based on secondary structure and motifs shared with known β‐(1,3)‐GalTs. Ninety‐four plant sequences are assigned to CAZy family GT31, including 33 fromArabidopsis thaliana(At), and 39 fromOryza sativa(Os), but only one plant enzyme has as yet been biochemically characterized, At‐GalT1, which is involved in the production of the Lewisastructure ofN‐glycans (Gal β‐(1,3)‐GlcNAc). Phylogenetic analysis identified 11 distinct clades, of which 4 are plant‐specific. Clade 1 proteins contain the plant‐specific DUF604 domain. Clade 7 is defined by a galectin‐containing domain and both clades 7 and 10 contain GalT domains. The possible substrate specificity of these enzymes is predicted. Clade 11 proteins contain no obvious domains so no function can be assigned. Enzymes in clades 7 and 10 are speculated to be involved in the synthesis of both proteoglycans, such as AGPs, andN‐glycans.
Glycosyltransferases of theGT34andGT37Families
Authors: Keegstra Kenneth , Cavalier David 
Published: May 2017

AbstractCAZy family GT37 contains 10 genes in Arabidopsis and a similar or higher number in other plant species. One of the Arabidopsis genes encodes a fucosyltransferase that is involved in xyloglucan biosynthesis. The biological role of the other genes in this family is not known, but it has been postulated that they all encode fucosyltransferases that are responsible for the addition of fucose to various cell wall polymers. If this hypothesis is correct, all the genes in this family encode proteins that perform the same biochemical function, i.e. transfer of fucose, but their biological roles are different. In contrast, the genes in CAZy family GT34 are known to encode proteins with two different biochemical functions. Some of the genes encode a galactosyltransferase that is involved in galactomannan biosynthesis. Other genes from this family encode xylosyltransferases that are involved in xyloglucan biosynthesis. Despite utilizing different donor molecules, both types of enzymes in this family utilize similar acceptors, creating an α‐1,6‐linked branch on the β‐1,4‐linked backbone.
Glycosyltransferases of the
GT
47 Family
Authors: Geshi Naomi , Harholt Jesper , Sakuragi Yumiko , Jensen Jacob Krüger , Scheller Henrik Vibe 
Published: May 2017

Abstract

CAZy glycosyltransferase family 47 (GT47) consists of enzymes that are all predicted to be inverting glycosyltransferases. The family includes enzymes with diverse donor and acceptor specificities, making it difficult to predict the function of family members that have not been biochemically characterized. The GT47 family is dominated by plant proteins, many or all of which are likely involved in cell wall biosynthesis and located in the Golgi vesicles. Based on the phylogeny, the plant sequences can be classified into six groups (A–E). Most of them remain to have their biochemical function determined, but a few members are relatively well characterized: MUR3 and XGD1 have been shown biochemically to function as xyloglucan β‐1,2‐galactosyltransferase and xylogalacturonan β‐1,3‐xylosyltransferase, respectively. Wall phenotype has been demonstrated in mutants of
arad1
,
gut1/irx10
and
fra8/irx7
, but biochemical function of the corresponding proteins remains to be elucidated. The mutant phenotypes suggest that ARAD1 functions as a pectin arabinosyltransferase while GUT1/IRX10L and FRA8/IRX7 are involved in xylan biosynthesis.
Herbivore Oral Secretions are the First Line of Protection Against Plant‐induced Defences
Authors: Felton Gary W , Chung Seung Ho , Hernandez Maria Gloria Estrada , Louis Joe , Peiffer Michelle , Tian Donglan 
Published: May 2017

AbstractIn order to mount a successful defence, plants must specifically recognize the threat (microbe vs. herbivore), elicit the appropriate signalling pathway (e.g. salicylic acid vs. jasmonic acid) and mount the proper defence. As effective counterploys, herbivores may disrupt defence signalling to suppress defences, detoxify defences, or even sequester these defences in their bodies to avoid toxicity. Our current research has focused on salivary effectors that disrupt plant defence signalling. Our hypothesis is that, as an alternative counterploy, some herbivores may present themselves in ‘disguise’ and thus avoid proper detection. We believe this alternative counterploy has been overlooked, but that it may represent a commonly used strategy by certain herbivores. Emerging evidence suggest that some herbivores may actively deposit microbes in their oral secretions on plants, and thus be ‘mistakenly’ recognized as microbes. Consequently, plants turn on the incorrect signalling pathway and express defences that are ineffective against these intruders.
Insect Detoxification and Sequestration Strategies
Authors: Heckel David G. 
Published: May 2017

AbstractPlants defend themselves from insect herbivores with a vast array of chemical defences, yet insects have evolved several mechanisms for detoxifying these and even sequestering them for their own use. Gene duplication within the large cytochrome P450 gene family plays diverse roles in detoxification, employing fine‐tuning of substrate specificity, transcriptional control and insensitivity to plant‐derived P450 inhibitors. Multiple mechanisms exist for avoiding activation of glucosinolates and cyanogenic glucosides, and for sequestering or even synthesizing the latter. Housekeeping enzymes have been re‐directed to novel detoxicative functions. Often, the primary molecular target of the plant toxin has mutated to a less sensitive form, and multiple parallel evolutionary responses of this type can be seen in communities of herbivores consuming plants posing the same chemical challenges. These and other mechanisms have enabled insects to continue to exploit plants for food throughout the long history of their co‐evolutionary struggle.
Plant Semiochemicals – Perception and Behavioural Responses by Insects
Authors: Reinecke Andreas , Hilker Monika 
Published: May 2017

AbstractPlants provide chemical cues that are specific for species, plant organs and the (a)biotic environmental conditions. Insects exploit these cues for various purposes, such as habitat and host plant location, host quality assessment, aggregation, mate finding and location of herbivorous prey. The process of sensing plant infochemicals may be described as multi‐stage filtering that starts at the surface and pores of the sensory organs, continues in the sensillum lumen, with its aqueous phase containing carrier molecules, and molecular receptors in the dendritic membranes of the actual sensory cells. This chemosensory input elicits behavioural responses to plant odour that depend on chemical background information, on habitat features determining how chemical cues travel through space, and on the physiological, as well as motivational, state of the insect. Hence, insect olfactory orientation by plant odours is mediated by a fine‐tuneable olfactory system that is continuously adjusted to the actual needs of the insect.
Transcriptome Responses in Herbivorous Insects Towards Host Plant and Toxin Feeding
Authors: Vogel Heiko , Musser Richard O , de la Paz Celorio‐Mancera Maria 
Published: May 2017

AbstractFood source is a major determinant of physiological performance and a strong selection force for insect herbivores. The ability to adequately respond to chemical challenges posed by their host plants is the primary determinant of larval fitness. Most herbivorous insects must consume large quantities of plant material to meet their nutritional requirements and, at the same time, cope with numerous mechanical, chemical and protein‐based defences posed by their sessile hosts. Despite the importance of host plants on essential life history traits of insect herbivores, data on global responses to both individual plant‐derived compounds and plant feeding is scarce. Here we discuss the existing data on herbivore responses to host plant exposure, toxin feeding or nutrient limitations, and we make an attempt at identifying changes in genome‐wide expression patterns of generalist and/or specialist herbivores. While generalists face an array of different plant defences, and therefore likely need to invest in broad detoxifying strategies, specialist herbivores need to fine‐tune their adaptation to specific plant defences.
Acenaphtho[1, 2‐k]fluoranthene‐Fused Diimide Derivatives: An Investigation of the Relationship Between Molecular Structure and Device Performance
Authors: Ding Lin , Yang Chi‐Yuan , Zheng Yu‐Qing , Wang Jie‐Yu , Pei Jian , Su Zhongmin 
Published: May 2017

AbstractOrganic electron‐acceptor materials play an important role in organic electronics, especially in organic bulk heterojunction (BHJ) solar cells. Recently, many non‐fullerene small molecular acceptors have been developed, in which aromatic fused‐imides were proven to be a promising family of excellent electron acceptors. We developed a series of acenaphtho[1,2‐k]fluoranthene‐fused diimides, AFIs (AFI1, AFI2 and AFI3), employing the Diels–Alder reaction as the crucial synthetic step. With electron‐withdrawing diimide groups in their large conjugated backbone, AFIs display a LUMO level around −3.50 eV. These AFI compounds were used as the electron acceptors to fabricate organic photovoltaic devices. The power conversion efficiency (PCE) of up to 2.37 % was achieved with a high open‐circuit voltage (Voc) up to 0.96 V.
Skeletal maturity of the hand in an East African group from Sudan
Authors: Elamin Fadil , Abdelazeem Nihal , Elamin Ahmed , Saif Duaa , Liversidge Helen M. 
Published: May 2017

AbstractObjectivesStudies of skeletal maturity from Africa indicate a delay, reflected in a negative relative skeletal age (RSA). This study aims to evaluate the influence of age, socioeconomic status (SES) and nutritional status on skeletal maturation in a large sample of children from North Sudan.MaterialsThe sample consisted 665 males and 1018 females from 3‐25 years from Khartoum. Height, weight, age of menarche and, SES were recorded of patients attending for dental treatment.MethodsSkeletal age was assigned from hand‐wrist radiographs using the Greulich‐Pyle (GP) atlas (1952). RSA (difference between skeletal and chronological ages) was compared in groups divided by age, sex, height‐for‐age and body‐mass‐index z scores, and SES. Spearman's correlation and studentt‐test was used to compare groups.ResultsDelayed skeletal age was noted across all age in boys. In girls, a delay was observed between ages 6‐10, while advancement occurred between ages 13–18. Maturity was delayed in low height groups (p < .05) and low SES groups. RSA was negatively associated with HAZ in low SES males (R = −0.0.27,p < .001) and low SES females (R = −0.32,p < .001).ConclusionsThere were statistically significant skeletal delays in North Sudanese males and most pre‐menarche females, low height and low SES groups. Post‐menarche females were advanced relative to males and GP references. Low SES impacts were statistically correlated to skeletal delay.
Ligand‐Promoted Rhodium(III)‐Catalyzed ortho‐C−H Amination with Free Amines
Authors: Wang Huai‐Wei , Lu Yi , Zhang Bing , He Jian , Xu Hua‐Jin , Kang Yan‐Shang , Sun Wei‐Yin , Yu Jin‐Quan 
Published: May 2017

AbstractLigand development for rhodium(III)‐catalyzed C−H activation reactions has largely been limited to cyclopentadienyl (Cp) based scaffolds. 2‐Methylquinoline has now been identified as a feasible ligand that can coordinate to the metal center of Cp*RhCl to accelerate the cleavage of the C−H bond of N‐pentafluorophenylbenzamides, providing a new structural lead for ligand design. The compatibility of this reaction with secondary free amines and anilines also overcomes the limitations of palladium(II)‐catalyzed C−H amination reactions.
Effect of microstructure on the dielectric properties of poly(vinyl alcohol)–poly(3,4‐ethylenedioxythiophene) doped with poly(styrenesulfonate) composite films
Authors: Mydhili V. , Manivannan S. 
Published: May 2017

ABSTRACTPoly(3,4‐ethylenedioxythiophene) doped with poly(styrenesulfonate) (PEDOT–PSS) was blended with poly(vinyl alcohol) (PVA) to form 0, 10, 20, 30, 40, and 50 vol % PEDOT–PSS/PVA solutions, and their freestanding films were prepared with a simple and cost‐effective solution casting technique at 27 °C in the absence of additives. Field emission scanning electron microscopy images revealed changes in the cocontinuous network to a rodlike morphology in the composite films from 10 to 50 vol % PEDOT–PSS/PVA. The alternating‐current conductivity was found to obey Jonscher's power law. The obtained values of the dielectric constant at 27 °C were relatively high, and a maximum value of 6.7 × 104 at 100 Hz for 40 vol % PEDOT–PSS'/PVA was observed. The dielectric loss attained a maximum value of about 106 at 100 Hz for 40 vol % PEDOT–PSS/PVA. However, a decrease in the dielectric parameters was observed at 50 vol % PEDOT–PSS/PVA because of locally induced strain in the microstructure. The variations in polarization with respect to the applied electric field (P–E) were determined for 50, 100, and 500 Hz at 500 V for the freestanding composite films of lower concentrations up to 20 vol % PEDOT–PSS/PVA. In summary, the dielectric and P–E measurements confirmed that the electrical characteristics changed in accordance to the contribution from both resistive and capacitive sites in the PEDOT–PSS/PVA composites. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45079.
Die intelligente Brücke im digitalen Testfeld Autobahn
Authors: Haardt Peter , Dabringhaus Sarah , Friebel Wolf Dieter , Bayerstorfer Robert , Bäumler Tobias , Freundt Ursula 
Published: May 2017

AbstractUnter dem Begriff „Intelligente Brücke” erfolgt in einem Forschungscluster der Bundesanstalt für Straßenwesen die Entwicklung eines adaptiven Systems zur kontinuierlichen Bereitstellung relevanter Informationen für eine ganzheitliche Zustandsbewertung durch den Einsatz von geeigneter Sensorik in Verbindung mit Analyse‐ und Bewertungsverfahren. Hierdurch werden online Hinweise auf zu erwartende Schädigungen und Zustandsänderungen ermöglicht. Im Rahmen des digitalen Testfelds Autobahn werden ausgewählte Entwicklungen „Einwirkungsüberwachung”, „Instrumentierte Fahrbahnübergänge und Lager” sowie „Sensornetze” an einer Spannbetonbrücke im Autobahnkreuz Nürnberg umfänglich vorgestellt und damit bundesweit zugänglich gemacht. Das Gesamtsystem besteht aus den Komponenten eines Informationssystems zur Analyse und Bewertung von Messdaten instrumentierter Bauteile. Die dabei durchzuführenden Untersuchungen beziehen sich auf die fortlaufende Aktualisierung des objektbezogenen Lastmodells und Analysen zur Restlebensdauer der Brücke sowie der untersuchten Bauteile. Die erfassten und aufbereiteten Informationen werden der zuständigen Straßenbauverwaltung online zur Verfügung gestellt. Das System wird im Rahmen eines fünfjährigen Untersuchungsprogramms betrieben, analysiert und weiterentwickelt.
In vitro evaluation of potential transporter‐mediated drug interactions of evogliptin
Authors: Lee Dae Y. , Chae Hye W. , Shim Hyun J. 
Published: May 2017

AbstractTo date, little is known about the transporter‐mediated drug–drug interaction (DDI) potential of evogliptin, a novel DPP‐4 inhibitor. The objective of this study was to evaluate the DDI potential of evogliptin using various in vitro assays in transporter‐expressing cell lines. After incubating evogliptin with cells overexpressing OAT1, OAT3, OCT2, OATP1B1 and OATP1B3, there was no notable cellular accumulation of evogliptin (fold accumulation, 0.41–1.86). In bidirectional transport assays using a Caco‐2 cell monolayer, a high efflux ratio (ER, 522) of evogliptin was observed, which was significantly decreased (97.96%) in the presence of a potent P‐gp inhibitor. In assays using MDCKII‐BCRP cell monolayers, by contrast, a low net ER (1.16–1.26) was found. In similar cellular uptake and bidirectional studies with probe substrates of P‐gp, BCRP, OAT1, OAT3, OCT2, OATP1B1 and OATP1B3, the active transport of the substrates was not significantly suppressed by evogliptin. These results suggest that evogliptin may be a substrate of P‐gp, but not a substrate of BCRP, OAT1B1, OAT1B3, OAT1, OAT3 or OCT2, and not an inhibitor of any of these transporters. Therefore, it could be concluded that evogliptin has some DDI potential involving P‐gp, but it has low potential of DDI mediated by the other transporters.
What Provides Justification for Cheating—Producing or Observing Counterfactuals?
Authors: Bassarak Claudia , Leib Margarita , Mischkowski Dorothee , Strang Sabrina , Glöckner Andreas , Shalvi Shaul 
Published: May 2017

AbstractWhen people can profit financially by lying, they do so to the extent to which they can justify their lies. One type of justification is the observation and production of desirable counterfactual information. Here, we disentangle observing and producing of desired counterfactuals and test whether the mere observation is sufficient or whether one actually needs to produce the information in order to justify lying. By employing a modified version of the Die‐Under‐Cup task, we ask participants to privately roll a die three times and to report the outcome of the first die roll (with higher values corresponding to higher payoffs). In all three conditions, participants produce (roll the die) and observe the first die roll, which is relevant for pay. We manipulate whether participants produce and observe versus only observe the second and third die roll outcomes, which are both irrelevant for pay. Results reveal that people lie to the same extent—when producing and observing the counterfactuals, and when merely observing them. It seems that merely observing counterfactual information is sufficient to allow people to use this information to justify their lies. We further test whether creativity and moral disengagement are associated with dishonesty and replicate the finding showing that unethical behavior increases with creativity. Copyright © 2017 John Wiley & Sons, Ltd.