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Abstract: Little is known about the structures of the xyloglucans in the primary cell walls of vascular plants (tracheophytes) other than angiosperms. Xyloglucan structures were examined in 13 species of gymnosperms, 13 species of monilophytes (ferns sensu lato), and two species of lycophytes. Wall preparations were obtained, extracted with 6M sodium hydroxide, and the extracts treated with a xyloglucan-specific endo-(1→4)-β-glucanase preparation. The oligosaccharides released were analysed by matrix-assisted laser-desorption ionisation time-of-flight mass spectrometry and by high-performance anion-exchange chromatography. The xyloglucan oligosaccharide profiles from the gymnosperm walls were similar to those from the walls of most eudicotyledons and non-commelinid monocotyledons, indicating that the xyloglucans were fucogalactoxyloglucans, containing the fucosylated units XXFG and XLFG. The xyloglucan oligosaccharide profiles for six of the monilophyte species were similar to those of the gymnosperms, indicating they were also fucogalactoxyloglucans. Phylogenetically, these monilophyte species were from both basal and more derived orders. However, the profiles for the other monilophyte species showed various significant differences, including additional oligosaccharides. In three of the species, these additional oligosaccharides contained arabinosyl residues which were most abundant in the profile of Equisetum hyemale. The two species of lycophytes examined, Selaginella kraussiana and Lycopodium cernuum, had quite different xyloglucan oligosaccharide profiles, but neither were fucogalactoxyloglucans. The S. kraussiana profile had abundant oligosaccharides containing arabinosyl residues. The L. cernuum profile indicated the xyloglucan had a very complex structure. [Copyright &y& Elsevier]

Abstract: Wheat bran protects against mutations and cancer, but contains different plant cell types that are likely to have different protective effects. We previously described the production and chemical characterisation of an aleurone-rich fraction (ARF) and a pericarp-rich fraction (PRF) from wheat grain. We compared these with whole bran (WB), fed to rats as 10% of a high fat AIN-76 diet. All bran-supplemented diets increased faecal bulk, in the order PRF>WB>ARF. PRF increased the activity of NAD(P)H:quinone acceptor oxidoreductase only in the forestomach, whereas ARF and WB enhanced levels of glutathione S-transferase in the duodenum. ARF but not PRF was digested and fermented, and also encouraged bacterial growth. Rats were gavaged with the radioactive mutagen 14C-labelled IQ (2-amino-3-methylimidazo[4,5-f]quinoline), and effects of the brans on plasma radioactivity measured. Compared with the control diet, all bran-supplemented diets reduced the concentration of radioactivity in plasma, in the order ARF>PRF>WB. All brans increased faecal elimination of radioactivity, but only ARF and PRF enhanced urinary radioactivity. These data suggest that wheat bran may reduce mutation and cancers through direct adsorption and enhanced elimination of a dietary mutagen and/or its metabolites, and that wheat bran enriched in pericarp or aleurone cell walls may exert protective effects through different mechanisms. [Copyright &y& Elsevier]

Despite Wireless Sensor Networks (WSNs) significantly developing over the past decade, these networks, like most wireless networks, remain susceptible to malicious interference and spectrum coexistence. Other vulnerabilities arise as WSN applications adopt open standards and typically resource and energy-constrained commercial-off-the-shelf equipment. Deployments include safety-critical applications such as the internet of things, medical, aerospace and space and deep-sea exploration. To manage safety and privacy requirements across such a diverse wireless landscape, security on wireless edge devices needs improvement while maintaining low complexity. This paper improves wireless edge device security by developing a novel intelligent interference diagnostic framework. Received in-phase (I) and quadrature-phase (Q) samples are exclusively utilized to detect modern, subtle and traditional crude jamming attacks. This I/Q sample utilization inherently enables decentralized decision-making, where the low-order features were extracted in a previous study focused on classifying typical 2.4–2.5 GHz wireless signals. The associated optimal intelligent models are leveraged as the foundation for this paper's work. Initially, Matlab Monte Carlo simulations investigate the ideal case, which incorporates no hardware limitations, identifies the required data type of signal interactions and motivates a hardware investigation. Software-defined radios (SDRs) collect the required live over-the-air I/Q data and transmit matched signal (ZigBee) and continuous-wave interference in developed ZigBee wireless testbeds. Low complexity supervised machine learning models are developed based exclusively on the low-order features and achieve an average accuracy among the developed models above 98%. The designed methodology involves examining ZigBee over-the-air data for artificial jamming and SDR jamming of ZigBee signals transmitted from SDR and commercial (XBee) sources. This approach expands to a legitimate node classification technique and an overall algorithm for wireless edge device interference diagnostic tools. The investigation includes developing Support Vector Machine, XGBoost and Deep Neural Network (DNN) models, where XGBoost is optimal. Adapting the optimized models to global positioning system signals establishes the transferability of the designed methodology. Implementing the designed approaches on a Raspberry Pi embedded device examines a relatively resource-constrained deployment. The primary contribution is the real experimentally validated interference diagnostic framework that enables independent device operation, as no channel assumptions, network-level information or spectral images are required. Developed models exclusively use I/Q data low-order features and achieve high accuracy and generalization to unseen data. [ABSTRACT FROM AUTHOR]

Abstract: - Model composites, produced using cellulose from stationary cultures of the bacterium Gluconoacetobacter xylinus and tamarind xyloglucan, were examined by wide-angle X-ray scattering (WAXS) and CP/MAS solid-state 13C NMR spectroscopy. The dominant crystallite allomorph of cellulose produced in culture media with or without xyloglucan was cellulose Iα (triclinic). The presence of xyloglucan in the culture medium reduced the cross-section dimensions of the cellulose crystallites, but did not affect the crystallite allomorph. However, when the composites were refluxed in buffer, the proportion of cellulose Iβ allomorph increased relative to that of cellulose Iα. In contrast, cellulose Iα remained the dominant form when cellulose, produced in the absence of xyloglucan, was then heated in the buffer. Hence the presence of xyloglucan has a profound effect on the formation of the cellulose crystallites by G. xylinus. [Copyright &y& Elsevier]

Abstract: One full length (PrCESA10) and seven other cDNA clones (PrCESA2, 3, 5–8, 11) encoding cellulose synthases (CESAs) were isolated from the coniferous gymnosperm Pinus radiata. PrCESA10 encodes a protein predicted to contain the same domains and regions as angiosperm CESA genes: a zinc finger domain, a hypervariable region 1 (HVR1), a plant-conserved region (CR-P), a class-specific region or hypervariable region 2 (HVR2), in addition to the four conserved domains U1–U4 that are characteristic of the family 2 processive β-glycosyltransferases. The P. radiata protein is also predicted to contain eight transmembrane domains. The zinc finger domain, the CR-P and the C-terminal portion of the proteins, are highly conserved between P. radiata and the nearest angiosperm CESA protein from Solanum tuberosum. Reverse transcriptase-PCR showed that all the P. radiata genes were expressed in all organs tested, although to different extents. In situ hybridization studies with PrCESA10 in stems of 2- and 12-month-old seedlings showed that it was expressed in the secondary xylem in the two-to-three most recently developed tracheids, which were laying down secondary cell walls. [Copyright &y& Elsevier]

olid-state CP/MAS 13C NMR spectroscopy was used to determine the effects of three different sequential extraction procedures, used to remove non-cellulosic polysaccharides, on the molecular ordering of cellulose in a cell-wall preparation containing mostly primary cell walls obtained from the leaves of the model dicotyledon, Arabidopsis thaliana. The extractions were 50 mM trans-1,2-diaminocyclohexane N,N,N′,N′-tetraacetic acid (CDTA) and 50 mM sodium carbonate (giving Residue 1); 50 mM CDTA, 50 mM sodium carbonate and 1 M KOH (giving Residue 2); and 50 mM CDTA, 50 mM sodium carbonate and 4 M KOH (giving Residue 3). The molecular ordering of cellulose in Residue 1 was similar to that in unextracted walls: the cellulose was almost all crystalline, with 43% of molecules contained in crystallite interiors and similar proportions of the triclinic (Iα) and monoclinic (Iβ) crystal forms. Residue 2 was partly decrystallized and the remaining crystallites were mostly in the Iβ form. Residue 3 was a mixture of cellulose II, cellulose I and amorphous cellulose. The presence of signals at 100.0 and 102.3 ppm in the spectra of Residues 1 and 2, but not of unextracted cell walls, suggested that the extractions giving these residues caused some of the non-cellulosic polysaccharides, possibly xyloglucans and galactoglucomannans, to become relatively well ordered, for example through interactions with cellulose crystallite surfaces. [Copyright &y& Elsevier]

The xyloglucans of monocotyledons are known to vary in the abundance of fucosylated side chains, with most commelinid monocotyledons having xyloglucans with lower proportions than non-commelinid monocotyledons. In many commelinid species, and some non-commelinid species that have lower proportions of fucosylated side chains, these side chains have been shown to be cell-type specific. To determine whether it is just the fucosylated side chains that are cell-type specific, or whether xyloglucan is cell-type specific in these species, we used the monoclonal antibody LM15 in conjunction with immmunofluorescence microscopy. We examined the distribution of cell-wall labelling among cell types in these species. The primary walls of all cell types were shown to contain xyloglucans in all species that had cell-type specific distributions of fucosylated side chains. This indicates that it is the fucosylated side chains of xyloglucans that is cell-type specific. Although the functional significance of xyloglucan fucosylation remains unknown, such cell-type specificity supports hypotheses that the fucosylated side chains may indeed have a functional role within the cell wall. Image 1 • Cell walls of monocotyledons without fucogalactoxyloglucans do contain xyloglucans. • The primary cell walls of all cell types examined contain xyloglucans. • Fucosylation of monocotyledon xyloglucans must be regulated by cell type. [ABSTRACT FROM AUTHOR]

Near infrared (NIR) spectroscopy coupled with partial least squares (PLS-1) regression was used to predict the lignin contents and monosaccharide compositions of milled wood of Pinus radiata . The effects of particle size and moisture content were investigated by collecting NIR spectra of four sample types: large (<0.422 mm) and small (<0.178 mm) particles, in both ambient and dry conditions. PLS-1 models were constructed using mixtures of compression wood (CW) and opposite wood (OW) that provided a linear range of cell-wall compositions. Our results show that lignin contents and monosaccharide compositions of pure CWs and OWs can be successfully predicted using NIR spectra of all four sample types. However, large particles in ambient conditions have the most efficient preparation and the standard error (SE) values for lignin (2.10%), arabinose (0.34%), xylose (1.33%), galactose (2.54%), glucose (6.98%), mannose (1.48%), galacturonic acid (0.22%), glucuronic acid (0.06%), and 4- O -methylglucuronic acid (0.25%) were achieved. [ABSTRACT FROM AUTHOR]

The exopolysaccharides of the Gram-positive bacterium Romboutsia ilealis have recently been shown to include (1,3;1,4)-β-D-glucans. In the present study, we examined another Clostridia bacterium Clostridium ventriculi that has long been considered to contain abundant amounts of cellulose in its exopolysaccharides. We treated alcohol insoluble residues of C. ventriculi that include the exopolysaccharides with the enzyme lichenase that specifically hydrolyses (1,3;1,4)-β-D-glucans, and examined the oligosaccharides released. This showed the presence of (1,3;1,4)-β-D-glucans, which may have previously been mistaken for cellulose. Through genomic analysis, we identified the two family 2 glycosyltransferase genes CvGT2–1 and CvGT2 –2 as possible genes encoding (1,3;1,4)-β-D-glucan synthases. Gain-of-function experiments in the yeast Saccharomyces cerevisiae demonstrated that both of these genes do indeed encode (1,3;1,4)-β-D-glucan synthases. [Display omitted] [ABSTRACT FROM AUTHOR]

Tilted stems of softwoods form compression wood (CW) and opposite wood (OW) on their lower and upper sides, respectively. More is known about the most severe form of CW, severe CW (SCW), but mild CWs (MCWs) also occur widely. Two grades of MCWs, MCW1 and MCW2, as well as SCW and OW were identified in the stems of radiata pine ( Pinus radiata ) that had been slightly tilted. The four wood types were identified by the distribution of lignin in the tracheid walls determined by fluorescence microscopy. A solution of the fluorescent dye acridine orange (AO) (0.02% at pH 6 or 7) was shown to metachromatically stain the tracheid walls and can also be used to determine lignin distribution. The lignified walls fluoresced orange to yellow depending on the lignin concentration. Microscopically well-characterized discs (0.5 mm diameter) of the wood types were used to determine lignin concentrations and lignin monomer compositions using the acetyl bromide method and thioacidolysis, respectively. Lignin concentration and the proportion of p- hydroxyphenyl units (H-units) relative to guaiacyl (G-units) increased with CW severity, with <1% H-units in OW and up to 14% in SCW. Lignin H-units can be used as a marker for CW and CW severity. Similar discs were also examined by Raman and FTIR micro-spectroscopies coupled with principal component analysis (PCA) to determine if these techniques can be used to differentiate the four different wood types. Both techniques were able to do this, particularly Raman micro-spectroscopy. [ABSTRACT FROM AUTHOR]

Summary: Anthocyanins, which are O-glycosylated derivatives of anthocyanidins, are responsible for the red, blue and purple coloration of many organs of angiosperms where they have previously been reported to occur in vacuoles and cytoplasm. However, bright-field microscopy of sections of the storage roots of the sweet potato (Ipomoea batatas) clone 99N1/222, which contains high concentrations of anthocyanins, showed that the walls of the periderm cork cells (skin), but not those of the adjacent parenchyma cells, were coloured bright red/purple. In situ absorption spectra of the periderm cell walls were similar to those of methanolic solutions of anthocyanins. Dry cell-wall preparations obtained from the periderm and parenchyma tissues were coloured deep reddish-brown and white, respectively. Pigment was extracted from the periderm cell-wall preparation by treating with 1M NaOH. Acid hydrolysis of this extract followed by HPLC indicated the presence of the anthocyanidins cyanidin and peonidin. It is concluded that the periderm cell walls contain covalently bound anthocyanidin-containing compounds, possibly anthocyanins. [Copyright &y& Elsevier]

Abstract: The polysaccharide compositions of cell walls isolated from the laminae and midribs of chicory (cv. Grasslands Puna II) leaves were investigated. The walls, which, except for the walls of xylem tracheary elements in vascular bundles, were non-lignified, were fractionated progressively with 50mM CDTA, 50mM Na2CO3, 1M KOH, 4M KOH, 4M KOH+3.5% H3BO3, and hot water. Monosaccharide and linkage analyses of the polysaccharides in the walls and wall fractions indicated that the polysaccharides were similar to those in the non-lignified walls of other dicotyledons. However, the proportions of pectic polysaccharides were particularly high (67% of the total wall polysaccharides in the laminae). These included homogalacturonans (50% of the total wall polysaccharides in the laminae) and rhamnogalacturonan-I (RG-I). In contrast, the proportions of cellulose, xyloglucans, heteroxylans and glucomannans were particularly low. The xyloglucans were probably fucogalactoxyloglucans. The wall polysaccharides from the leaf laminae differed from those from the midribs in having higher proportions of homogalacturonans, lower proportions of non-pectic polysaccharides, and RG-I with a higher ratio of galactan to arabinan. [Copyright &y& Elsevier]