SpyB, a Small Heme-Binding Protein, Affects the Composition of the Cell Wall in Streptococcus pyogenes.

PubMed

Edgar, Rebecca J; Chen, Jing; Kant, Sashi; Rechkina, Elena; Rush, Jeffrey S; Forsberg, Lennart S; Jaehrig, Bernhard; Azadi, Parastoo; Tchesnokova, Veronika; Sokurenko, Evgeni V; Zhu, Haining; Korotkov, Konstantin V; Pancholi, Vijay; Korotkova, Natalia

2016-01-01

Streptococcus pyogenes (Group A Streptococcus or GAS) is a hemolytic human pathogen associated with a wide variety of infections ranging from minor skin and throat infections to life-threatening invasive diseases. The cell wall of GAS consists of peptidoglycan sacculus decorated with a carbohydrate comprising a polyrhamnose backbone with immunodominant N-acetylglucosamine side-chains. All GAS genomes contain the spyBA operon, which encodes a 35-amino-acid membrane protein SpyB, and a membrane-bound C3-like ADP-ribosyltransferase SpyA. In this study, we addressed the function of SpyB in GAS. Phenotypic analysis of a spyB deletion mutant revealed increased bacterial aggregation, and reduced sensitivity to β-lactams of the cephalosporin class and peptidoglycan hydrolase PlyC. Glycosyl composition analysis of cell wall isolated from the spyB mutant suggested an altered carbohydrate structure compared with the wild-type strain. Furthermore, we found that SpyB associates with heme and protoporphyrin IX. Heme binding induces SpyB dimerization, which involves disulfide bond formation between the subunits. Thus, our data suggest the possibility that SpyB activity is regulated by heme.

Chapter 3 Cell Wall Chemistry

Treesearch

Roger M. Rowell; Roger Pettersen; Mandla A. Tshabalala

2012-01-01

Wood is best defined as a three-dimensional biopolymer composite composed of an interconnected network of cellulose, hemicelluloses and lignin with minor amounts of extractives, and inorganics. The major chemical component of a living tree is water, but on a dry weight basis, all wood cell walls consist mainly of sugar-based polymers (carbohydrates, 65-75%) that are...

Biomass Yield and Carbohydrate Composition in Sugarcane and Energy Cane

USDA-ARS?s Scientific Manuscript database

Sugarcane and energy cane are important crops for sugar and bio-ethanol production. A better understanding their carbohydrate composition and concentrations in addition to biomass yields can improve knowledge in biomass processing and utilization. There were two objectives for this study. The first ...

Microbial degradation of complex carbohydrates in the gut.

PubMed

Flint, Harry J; Scott, Karen P; Duncan, Sylvia H; Louis, Petra; Forano, Evelyne

2012-01-01

Bacteria that colonize the mammalian intestine collectively possess a far larger repertoire of degradative enzymes and metabolic capabilities than their hosts. Microbial fermentation of complex non-digestible dietary carbohydrates and host-derived glycans in the human intestine has important consequences for health. Certain dominant species, notably among the Bacteroidetes, are known to possess very large numbers of genes that encode carbohydrate active enzymes and can switch readily between different energy sources in the gut depending on availability. Nevertheless, more nutritionally specialized bacteria appear to play critical roles in the community by initiating the degradation of complex substrates such as plant cell walls, starch particles and mucin. Examples are emerging from the Firmicutes, Actinobacteria and Verrucomicrobium phyla, but more information is needed on these little studied groups. The impact of dietary carbohydrates, including prebiotics, on human health requires understanding of the complex relationship between diet composition, the gut microbiota and metabolic outputs.

The cell wall: a carbohydrate armour for the fungal cell.

PubMed

Latgé, Jean-Paul

2007-10-01

The cell wall is composed of a polysaccharide-based three-dimensional network. Considered for a long time as an inert exoskeleton, the cell wall is now seen as a dynamic structure that is continuously changing as a result of the modification of culture conditions and environmental stresses. Although the cell wall composition varies among fungal species, chemogenomic comparative analysis have led to a better understanding of the genes and mechanisms involved in the construction of the common central core composed of branched beta1,3 glucan-chitin. Because of its essential biological role, unique biochemistry and structural organization and the absence in mammalian cells of most of its constitutive components, the cell wall is an attractive target for the development of new antifungal agents. Genomic as well as drug studies have shown that the death of the fungus can result from inhibition of cell wall polysaccharide synthases. To date, only beta1,3 glucan synthase inhibitors have been launched clinically and many more targets remain to be explored.

Determination of carbohydrate profile in sugarbeet (Beta vulgaris) cell walls

USDA-ARS?s Scientific Manuscript database

Sugarbeet germplasms USH20, C869, EL55, EL54 were used, and different tissues at different developmental stages were sampled, including dry seeds, germinating seedlings, developing leaves, mature leaves, petioles, hypocotyls, mature roots, flowering stems and inflorescences. Cell Wall Composition An...

Ultrastructure and Composition of the Nannochloropsis gaditana Cell Wall

PubMed Central

Scholz, Matthew J.; Weiss, Taylor L.; Jinkerson, Robert E.; Jing, Jia; Roth, Robyn; Goodenough, Ursula; Posewitz, Matthew C.

2014-01-01

Marine algae of the genus Nannochloropsis are promising producers of biofuel precursors and nutraceuticals and are also harvested commercially for aquaculture feed. We have used quick-freeze, deep-etch electron microscopy, Fourier transform infrared spectroscopy, and carbohydrate analyses to characterize the architecture of the Nannochloropsis gaditana (strain CCMP 526) cell wall, whose recalcitrance presents a significant barrier to biocommodity extraction. The data indicate a bilayer structure consisting of a cellulosic inner wall (∼75% of the mass balance) protected by an outer hydrophobic algaenan layer. Cellulase treatment of walls purified after cell lysis generates highly enriched algaenan preparations without using the harsh chemical treatments typically used in algaenan isolation and characterization. Nannochloropsis algaenan was determined to comprise long, straight-chain, saturated aliphatics with ether cross-links, which closely resembles the cutan of vascular plants. Chemical identification of >85% of the isolated cell wall mass is detailed, and genome analysis is used to identify candidate biosynthetic enzymes. PMID:25239976

Bacterial cell wall composition and the influence of antibiotics by cell-wall and whole-cell NMR

PubMed Central

Romaniuk, Joseph A. H.; Cegelski, Lynette

2015-01-01

The ability to characterize bacterial cell-wall composition and structure is crucial to understanding the function of the bacterial cell wall, determining drug modes of action and developing new-generation therapeutics. Solid-state NMR has emerged as a powerful tool to quantify chemical composition and to map cell-wall architecture in bacteria and plants, even in the context of unperturbed intact whole cells. In this review, we discuss solid-state NMR approaches to define peptidoglycan composition and to characterize the modes of action of old and new antibiotics, focusing on examples in Staphylococcus aureus. We provide perspectives regarding the selected NMR strategies as we describe the exciting and still-developing cell-wall and whole-cell NMR toolkit. We also discuss specific discoveries regarding the modes of action of vancomycin analogues, including oritavancin, and briefly address the reconsideration of the killing action of β-lactam antibiotics. In such chemical genetics approaches, there is still much to be learned from perturbations enacted by cell-wall assembly inhibitors, and solid-state NMR approaches are poised to address questions of cell-wall composition and assembly in S. aureus and other organisms. PMID:26370936

Genotype, development and tissue-derived variation of cell-wall properties in the lignocellulosic energy crop Miscanthus

DOE Office of Scientific and Technical Information (OSTI.GOV)

da Costa, Ricardo M. F.; Lee, Scott J.; Allison, Gordon G.

Species and hybrids of the genus Miscanthus contain attributes that make them front-runners among current selections of dedicated bioenergy crops. A key trait for plant biomass conversion to biofuels and biomaterials is cell-wall quality; however, knowledge of cell-wall composition and biology in Miscanthus species is limited. This study presents data on cell-wall compositional changes as a function of development and tissue type across selected genotypes, and considers implications for the development of miscanthus as a sustainable and renewable bioenergy feedstock. Cell-wall biomass was analysed for 25 genotypes, considering different developmental stages and stem vs. leaf compositional variability, by Fourier transformmore » mid-infrared spectroscopy and lignin determination. In addition, a Clostridium phytofermentans bioassay was used to assess cell-wall digestibility and conversion to ethanol. Important cell-wall compositional differences between miscanthus stem and leaf samples were found to be predominantly associated with structural carbohydrates. Lignin content increased as plants matured and was higher in stem tissues. Although stem lignin concentration correlated inversely with ethanol production, no such correlation was observed for leaves. Leaf tissue contributed significantly to total above-ground biomass at all stages, although the extent of this contribution was genotype-dependent. In conclusion, it is hypothesized that divergent carbohydrate compositions and modifications in stem and leaf tissues are major determinants for observed differences in cell-wall quality. The findings indicate that improvement of lignocellulosic feedstocks should encompass tissue-dependent variation as it affects amenability to biological conversion. For gene-trait associations relating to cell-wall quality, the data support the separate examination of leaf and stem composition, as tissue-specific traits may be masked by considering only total above-ground biomass

Genotype, development and tissue-derived variation of cell-wall properties in the lignocellulosic energy crop Miscanthus

DOE PAGES

da Costa, Ricardo M. F.; Lee, Scott J.; Allison, Gordon G.; ...

2014-04-15

Species and hybrids of the genus Miscanthus contain attributes that make them front-runners among current selections of dedicated bioenergy crops. A key trait for plant biomass conversion to biofuels and biomaterials is cell-wall quality; however, knowledge of cell-wall composition and biology in Miscanthus species is limited. This study presents data on cell-wall compositional changes as a function of development and tissue type across selected genotypes, and considers implications for the development of miscanthus as a sustainable and renewable bioenergy feedstock. Cell-wall biomass was analysed for 25 genotypes, considering different developmental stages and stem vs. leaf compositional variability, by Fourier transformmore » mid-infrared spectroscopy and lignin determination. In addition, a Clostridium phytofermentans bioassay was used to assess cell-wall digestibility and conversion to ethanol. Important cell-wall compositional differences between miscanthus stem and leaf samples were found to be predominantly associated with structural carbohydrates. Lignin content increased as plants matured and was higher in stem tissues. Although stem lignin concentration correlated inversely with ethanol production, no such correlation was observed for leaves. Leaf tissue contributed significantly to total above-ground biomass at all stages, although the extent of this contribution was genotype-dependent. In conclusion, it is hypothesized that divergent carbohydrate compositions and modifications in stem and leaf tissues are major determinants for observed differences in cell-wall quality. The findings indicate that improvement of lignocellulosic feedstocks should encompass tissue-dependent variation as it affects amenability to biological conversion. For gene-trait associations relating to cell-wall quality, the data support the separate examination of leaf and stem composition, as tissue-specific traits may be masked by considering only total above-ground biomass

Genotype, development and tissue-derived variation of cell-wall properties in the lignocellulosic energy crop Miscanthus.

PubMed

da Costa, Ricardo M F; Lee, Scott J; Allison, Gordon G; Hazen, Samuel P; Winters, Ana; Bosch, Maurice

2014-10-01

Species and hybrids of the genus Miscanthus contain attributes that make them front-runners among current selections of dedicated bioenergy crops. A key trait for plant biomass conversion to biofuels and biomaterials is cell-wall quality; however, knowledge of cell-wall composition and biology in Miscanthus species is limited. This study presents data on cell-wall compositional changes as a function of development and tissue type across selected genotypes, and considers implications for the development of miscanthus as a sustainable and renewable bioenergy feedstock. Cell-wall biomass was analysed for 25 genotypes, considering different developmental stages and stem vs. leaf compositional variability, by Fourier transform mid-infrared spectroscopy and lignin determination. In addition, a Clostridium phytofermentans bioassay was used to assess cell-wall digestibility and conversion to ethanol. Important cell-wall compositional differences between miscanthus stem and leaf samples were found to be predominantly associated with structural carbohydrates. Lignin content increased as plants matured and was higher in stem tissues. Although stem lignin concentration correlated inversely with ethanol production, no such correlation was observed for leaves. Leaf tissue contributed significantly to total above-ground biomass at all stages, although the extent of this contribution was genotype-dependent. It is hypothesized that divergent carbohydrate compositions and modifications in stem and leaf tissues are major determinants for observed differences in cell-wall quality. The findings indicate that improvement of lignocellulosic feedstocks should encompass tissue-dependent variation as it affects amenability to biological conversion. For gene-trait associations relating to cell-wall quality, the data support the separate examination of leaf and stem composition, as tissue-specific traits may be masked by considering only total above-ground biomass samples, and sample

Micro-Spectroscopic Imaging of Lignin-Carbohydrate Complexes in Plant Cell Walls and Their Migration During Biomass Pretreatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zeng, Yining; Zhao, Shuai; Wei, Hui

2015-04-27

In lignocellulosic biomass, lignin is the second most abundant biopolymer. In plant cell walls, lignin is associated with polysaccharides to form lignin-carbohydrate complexes (LCC). LCC have been considered to be a major factor that negatively affects the process of deconstructing biomass to simple sugars by cellulosic enzymes. Here, we report a micro-spectroscopic approach that combines fluorescence lifetime imaging microscopy and Stimulated Raman Scattering microscopy to probe in situ lignin concentration and conformation at each cell wall layer. This technique does not require extensive sample preparation or any external labels. Using poplar as a feedstock, for example, we observe variation ofmore » LCC in untreated tracheid poplar cell walls. The redistribution of LCC at tracheid poplar cell wall layers is also investigated when the chemical linkages between lignin and hemicellulose are cleaved during pretreatment. Our study would provide new insights into further improvement of the biomass pretreatment process.« less

Differential Effects of Two Fermentable Carbohydrates on Central Appetite Regulation and Body Composition

PubMed Central

Gibson, Glenn R.; Tuohy, Kieran M.; Sharma, Raj Kumar; Swann, Jonathan R.; Deaville, Eddie R.; Sleeth, Michele L.; Thomas, E. Louise; Holmes, Elaine; Bell, Jimmy D.; Frost, Gary

2012-01-01

Background Obesity is rising at an alarming rate globally. Different fermentable carbohydrates have been shown to reduce obesity. The aim of the present study was to investigate if two different fermentable carbohydrates (inulin and β-glucan) exert similar effects on body composition and central appetite regulation in high fat fed mice. Methodology/Principal Findings Thirty six C57BL/6 male mice were randomized and maintained for 8 weeks on a high fat diet containing 0% (w/w) fermentable carbohydrate, 10% (w/w) inulin or 10% (w/w) β-glucan individually. Fecal and cecal microbial changes were measured using fluorescent in situ hybridization, fecal metabolic profiling was obtained by proton nuclear magnetic resonance (1H NMR), colonic short chain fatty acids were measured by gas chromatography, body composition and hypothalamic neuronal activation were measured using magnetic resonance imaging (MRI) and manganese enhanced MRI (MEMRI), respectively, PYY (peptide YY) concentration was determined by radioimmunoassay, adipocyte cell size and number were also measured. Both inulin and β-glucan fed groups revealed significantly lower cumulative body weight gain compared with high fat controls. Energy intake was significantly lower in β-glucan than inulin fed mice, with the latter having the greatest effect on total adipose tissue content. Both groups also showed an increase in the numbers of Bifidobacterium and Lactobacillus-Enterococcus in cecal contents as well as feces. β- glucan appeared to have marked effects on suppressing MEMRI associated neuronal signals in the arcuate nucleus, ventromedial hypothalamus, paraventricular nucleus, periventricular nucleus and the nucleus of the tractus solitarius, suggesting a satiated state. Conclusions/Significance Although both fermentable carbohydrates are protective against increased body weight gain, the lower body fat content induced by inulin may be metabolically advantageous. β-glucan appears to suppress neuronal

Evolution and diversity of plant cell walls: from algae to flowering plants.

PubMed

Popper, Zoë A; Michel, Gurvan; Hervé, Cécile; Domozych, David S; Willats, William G T; Tuohy, Maria G; Kloareg, Bernard; Stengel, Dagmar B

2011-01-01

All photosynthetic multicellular Eukaryotes, including land plants and algae, have cells that are surrounded by a dynamic, complex, carbohydrate-rich cell wall. The cell wall exerts considerable biological and biomechanical control over individual cells and organisms, thus playing a key role in their environmental interactions. This has resulted in compositional variation that is dependent on developmental stage, cell type, and season. Further variation is evident that has a phylogenetic basis. Plants and algae have a complex phylogenetic history, including acquisition of genes responsible for carbohydrate synthesis and modification through a series of primary (leading to red algae, green algae, and land plants) and secondary (generating brown algae, diatoms, and dinoflagellates) endosymbiotic events. Therefore, organisms that have the shared features of photosynthesis and possession of a cell wall do not form a monophyletic group. Yet they contain some common wall components that can be explained increasingly by genetic and biochemical evidence.

Carbohydrate and nutrient composition of corn stover from three Southeastern USA locations

USDA-ARS?s Scientific Manuscript database

Corn (Zea mays L.) stover has been identified as an important feedstock for bioenergy and bio-product production. Our objective was to quantify nutrient removal, carbohydrate composition, theoretical ethanol yield (TEY) for various stover fractions. In 2009, 2010, and 2011, whole-plant samples were ...

Cell wall composition and digestibility alterations in Brachypodium distachyon achieved through reduced expression of the UDP-arabinopyranose mutase

USDA-ARS?s Scientific Manuscript database

Nucleotide-activated sugars are essential substrates for plant cell wall carbohydrate-polymer biosynthetic glycosyltransferase enzymes. The most prevalent sugars in grass cell walls include glucose (Glc), xylose (Xyl), and arabinose (Ara). These sugars are biosynthetically related via the uridine di...

Structural analysis of cell wall polysaccharides using PACE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mortimer, Jennifer C.

The plant cell wall is composed of many complex polysaccharides. The composition and structure of the polysaccharides affect various cell properties including cell shape, cell function and cell adhesion. Many techniques to characterize polysaccharide structure are complicated, requiring expensive equipment and specialized operators e.g. NMR, MALDI-MS. PACE (Polysaccharide Analysis using Carbohydrate gel Electrophoresis) uses a simple, rapid technique to analyze polysaccharide quantity and structure (Goubet et al. 2002). Whilst the method here describes xylan analysis, it can be applied (by use of the appropriate glycosyl hydrolase) to any cell wall polysaccharide.

UCP1 and UCP3 Expression Is Associated with Lipid and Carbohydrate Oxidation and Body Composition

PubMed Central

Oliveira, Bruno A. P.; Pinhel, Marcela A. S.; Nicoletti, Carolina F.; Oliveira, Cristiana C.; Quinhoneiro, Driele C. G.; Noronha, Natália Y.; Marchini, Júlio S.; Marchry, Ana J.; Junior, Wilson S.; Nonino, Carla B.

2016-01-01

Background/Objective Uncoupling proteins (UCPs) are located in the inner membrane of mitochondria. These proteins participate in thermogenesis and energy expenditure. This study aimed to evaluate how UCP1 and UCP3 expression influences substrate oxidation and elicits possible changes in body composition in patients submitted to bariatric surgery. Subjects/Methods This is a longitudinal study comprising 13 women with obesity grade III that underwent bariatric surgery and 10 healthy weight individuals (control group). Body composition was assessed by bioelectrical impedance. Carbohydrate and fat oxidation was determined by indirect calorimetry. Subcutaneous adipose tissue was collected for gene expression analysis. QPCR was used to evaluate UCP1 and UCP3 expression. Results Obese patients and the control group differed significantly in terms of lipid and carbohydrate oxidation. Six months after bariatric surgery, the differences disappeared. Lipid oxidation correlated with the percentage of fat mass in the postoperative period. Multiple linear regression analysis showed that the UCP1 and UCP3 genes contributed to lipid and carbohydrate oxidation. Additionally, UCP3 expression was associated with BMI, percentage of lean body mass, and percentage of mass in the postoperative period. Conclusions UCP1 and UCP3 expression is associated with lipid and carbohydrate oxidation in patients submitted to bariatric surgery. In addition, UCP3 participates in body composition modulation six months postoperatively. PMID:26959981

Carbohydrate-mediated responses during zygotic and early somatic embryogenesis in the endangered conifer, Araucaria angustifolia

PubMed Central

Elbl, Paula; De Souza, Amanda P.; Jardim, Vinicius; de Oliveira, Leandro F.; Macedo, Amanda F.; dos Santos, André L. W.; Buckeridge, Marcos S.; Floh, Eny I. S.

2017-01-01

Three zygotic developmental stages and two somatic Araucaria angustifolia cell lines with contrasting embryogenic potential were analyzed to identify the carbohydrate-mediated responses associated with embryo formation. Using a comparison between zygotic and somatic embryogenesis systems, the non-structural carbohydrate content, cell wall sugar composition and expression of genes involved in sugar sensing were analyzed, and a network analysis was used to identify coordinated features during embryogenesis. We observed that carbohydrate-mediated responses occur mainly during the early stages of zygotic embryo formation, and that during seed development there are coordinated changes that affect the development of the different structures (embryo and megagametophyte). Furthermore, sucrose and starch accumulation were associated with the responsiveness of the cell lines. This study sheds light on how carbohydrate metabolism is influenced during zygotic and somatic embryogenesis in the endangered conifer species, A. angustifolia. PMID:28678868

Titanium dioxide, single-walled carbon nanotube composites

DOEpatents

Yao, Yuan; Li, Gonghu; Gray, Kimberly; Lueptow, Richard M.

2015-07-14

The present invention provides titanium dioxide/single-walled carbon nanotube composites (TiO.sub.2/SWCNTs), articles of manufacture, and methods of making and using such composites. In certain embodiments, the present invention provides membrane filters and ceramic articles that are coated with TiO.sub.2/SWCNT composite material. In other embodiments, the present invention provides methods of using TiO.sub.2/SWCNT composite material to purify a sample, such as a water or air sample.

Carbohydrate-dependent binding of langerin to SodC, a cell wall glycoprotein of Mycobacterium leprae.

PubMed

Kim, Hee Jin; Brennan, Patrick J; Heaslip, Darragh; Udey, Mark C; Modlin, Robert L; Belisle, John T

2015-02-01

Langerhans cells participate in the immune response in leprosy by their ability to activate T cells that recognize the pathogen, Mycobacterium leprae, in a langerin-dependent manner. We hypothesized that langerin, the distinguishing C-type lectin of Langerhans cells, would recognize the highly mannosylated structures in pathogenic Mycobacterium spp. The coding region for the extracellular and neck domain of human langerin was cloned and expressed to produce a recombinant active trimeric form of human langerin (r-langerin). Binding assays performed in microtiter plates, by two-dimensional (2D) Western blotting, and by surface plasmon resonance demonstrated that r-langerin possessed carbohydrate-dependent affinity to glycoproteins in the cell wall of M. leprae. This lectin, however, yielded less binding to mannose-capped lipoarabinomannan (ManLAM) and even lower levels of binding to phosphatidylinositol mannosides. However, the superoxide dismutase C (SodC) protein of the M. leprae cell wall was identified as a langerin-reactive ligand. Tandem mass spectrometry verified the glycosylation of a recombinant form of M. leprae SodC (rSodC) produced in Mycobacterium smegmatis. Analysis of r-langerin affinity by surface plasmon resonance revealed a carbohydrate-dependent affinity of rSodC (equilibrium dissociation constant [KD] = 0.862 μM) that was 20-fold greater than for M. leprae ManLAM (KD = 18.69 μM). These data strongly suggest that a subset of the presumptively mannosylated M. leprae glycoproteins act as ligands for langerin and may facilitate the interaction of M. leprae with Langerhans cells. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Carbohydrate-Dependent Binding of Langerin to SodC, a Cell Wall Glycoprotein of Mycobacterium leprae

PubMed Central

Kim, Hee Jin; Brennan, Patrick J.; Heaslip, Darragh; Udey, Mark C.; Modlin, Robert L.

2014-01-01

Langerhans cells participate in the immune response in leprosy by their ability to activate T cells that recognize the pathogen, Mycobacterium leprae, in a langerin-dependent manner. We hypothesized that langerin, the distinguishing C-type lectin of Langerhans cells, would recognize the highly mannosylated structures in pathogenic Mycobacterium spp. The coding region for the extracellular and neck domain of human langerin was cloned and expressed to produce a recombinant active trimeric form of human langerin (r-langerin). Binding assays performed in microtiter plates, by two-dimensional (2D) Western blotting, and by surface plasmon resonance demonstrated that r-langerin possessed carbohydrate-dependent affinity to glycoproteins in the cell wall of M. leprae. This lectin, however, yielded less binding to mannose-capped lipoarabinomannan (ManLAM) and even lower levels of binding to phosphatidylinositol mannosides. However, the superoxide dismutase C (SodC) protein of the M. leprae cell wall was identified as a langerin-reactive ligand. Tandem mass spectrometry verified the glycosylation of a recombinant form of M. leprae SodC (rSodC) produced in Mycobacterium smegmatis. Analysis of r-langerin affinity by surface plasmon resonance revealed a carbohydrate-dependent affinity of rSodC (equilibrium dissociation constant [KD] = 0.862 μM) that was 20-fold greater than for M. leprae ManLAM (KD = 18.69 μM). These data strongly suggest that a subset of the presumptively mannosylated M. leprae glycoproteins act as ligands for langerin and may facilitate the interaction of M. leprae with Langerhans cells. PMID:25422308

Effects of supercritical carbon dioxide (SC-CO(2)) oil extraction on the cell wall composition of almond fruits.

PubMed

Femenia, A; García-Marín, M; Simal, S; Rosselló, C; Blasco, M

2001-12-01

Extraction of oil from almond fruits using supercritical carbon dioxide (SC-CO(2)) was carried out at 50 degrees C and 330 bar on three sets of almonds: raw almond seeds, raw almond kernels, and toasted almond seeds. Three different oil extraction percentages were applied on each set ranging from approximately 15 to 16%, from approximately 27 to 33%, and from approximately 49 to 64%. Although no major changes were detected in the fatty acid composition between fresh and partially defatted samples, carbohydrate analysis of partially defatted materials revealed important changes in cell wall polysaccharides from almond tissues. Thus, at low extraction percentages (up to approximately 33%), pectic polysaccharides and hemicellulosic xyloglucans were the main type of polymers affected, suggesting the modification of the cell wall matrix, although without breakage of the walls. Then, as supercritical fluid extraction (SCFE) continues and higher extraction rates are achieved (up to approximately 64%), a major disruption of the cell wall occurred as indicated by the losses of all major types of cell wall polysaccharides, including cellulose. These results suggest that, under the conditions used for oil extraction using SC-CO(2), fatty acid chains are able to exit the cells through nonbroken walls; the modification of the pectin-hemicellulose network might have increased the porosity of the wall. However, as high pressure is being applied, there is a progressive breakage of the cell walls allowing the free transfer of the fatty acid chains from inside the cells. These findings might contribute to providing the basis for the optimization of SCFE procedures based on plant food sources.

Compressive behavior of energy-saving fired facing brick composite wall

NASA Astrophysics Data System (ADS)

Guo, Kai; Wu, Cai

2018-03-01

The energy-saving fired facing brick composite wall has a broad development prospects due to its merits of thermal insulation, energy conservation, beautiful, and natural. The construction and characteristics of this wall are introduced and analyzed in this paper. Experimental studies of samples are also conducted to investigate its compressive performance. The results show that the energy-saving fired facing brick composite wall has high compressive capacity. It has considerable application prospect, the study in this paper provides foundation to further studies.

Inter-wall bridging induced peeling of multi-walled carbon nanotubes during tensile failure in aluminum matrix composites.

PubMed

Chen, Biao; Li, Shufeng; Imai, Hisashi; Umeda, Junko; Takahashi, Makoto; Kondoh, Katsuyoshi

2015-02-01

In situ scanning electron microscopy (SEM) observation of a tensile test was performed to investigate the fracturing behavior of multi-walled carbon nanotubes (MWCNTs) in powder metallurgy Al matrix composites. A multiple peeling phenomenon during MWCNT fracturing was clearly observed. Its formation mechanism and resultant effect on the composite strength were examined. Through transition electron microscopy characterizations, it was observed that defective structures like inter-wall bridges cross-linked adjacent walls of MWCNTs. This structure was helpful to improve the inter-wall bonding conditions, leading to the effective load transfer between walls and resultant peeling behaviors of MWCNTs. These results might provide new understandings of the fracturing mechanisms of carbon nanotube reinforcements for designing high-performance nanocomposites. Copyright © 2014 Elsevier Ltd. All rights reserved.

The carbohydrate-binding module (CBM)-like sequence is crucial for rice CWA1/BC1 function in proper assembly of secondary cell wall materials.

PubMed

Sato, Kanna; Ito, Sachiko; Fujii, Takeo; Suzuki, Ryu; Takenouchi, Sachi; Nakaba, Satoshi; Funada, Ryo; Sano, Yuzou; Kajita, Shinya; Kitano, Hidemi; Katayama, Yoshihiro

2010-11-01

We recently reported that the cwa1 mutation disturbed the deposition and assembly of secondary cell wall materials in the cortical fiber of rice internodes. Genetic analysis revealed that cwa1 is allelic to bc1, which encodes glycosylphosphatidylinositol (GPI)-anchored COBRA-like protein with the highest homology to Arabidopsis COBRA-like 4 (COBL4) and maize Brittle Stalk 2 (Bk2). Our results suggested that CWA1/BC1 plays a role in assembling secondary cell wall materials at appropriate sites, enabling synthesis of highly ordered secondary cell wall structure with solid and flexible internodes in rice. The N-terminal amino acid sequence of CWA1/BC1, as well as its orthologs (COBL4, Bk2) and other BC1-like proteins in rice, shows weak similarity to a family II carbohydrate-binding module (CBM2) of several bacterial cellulases. To investigate the importance of the CBM-like sequence of CWA1/BC1 in the assembly of secondary cell wall materials, Trp residues in the CBM-like sequence, which is important for carbohydrate binding, were substituted for Val residues and introduced into the cwa1 mutant. CWA1/BC1 with the mutated sequence did not complement the abnormal secondary cell walls seen in the cwa1 mutant, indicating that the CBM-like sequence is essential for the proper function of CWA1/BC1, including assembly of secondary cell wall materials.

Stover composition in maize and sorghum reveals remarkable genetic variation and plasticity for carbohydrate accumulation

DOE PAGES

Sekhon, Rajandeep S.; Breitzman, Matthew W.; Silva, Renato R.; ...

2016-06-08

Carbohydrates stored in vegetative organs, particularly stems, of grasses are a very important source of energy. We examined carbohydrate accumulation in adult sorghum and maize hybrids with distinct phenology and different end uses (grain, silage, sucrose or sweetness in stalk juice, and biomass). Remarkable variation was observed for nonstructural carbohydrates and structural polysaccharides during three key developmental stages both between and within hybrids developed for distinct end use in both species. At the onset of the reproductive phase (average 65 days after planting, DAP), a wide range for accumulation of non-structural carbohydrates (free glucose and sucrose combined), was observed inmore » internodes of maize (11-24%) and sorghum (7-36%) indicating substantial variation for transient storage of excess photosynthate during periods of low grain or vegetative sink strength. Remobilization of these reserves for supporting grain fill or vegetative growth was evident from lower amounts in maize (8-19%) and sorghum (9-27%) near the end of the reproductive period (average 95 DAP). At physiological maturity of grain hybrids (average 120 DAP), amounts of these carbohydrates were generally unchanged in maize (9-21%) and sorghum (16-27%) suggesting a loss of photosynthetic assimilation due to weakening sink demand. Nonetheless, high amounts of non-structural carbohydrates at maturity even in grain maize and sorghum (15-18%) highlight the potential for developing dual-purpose (grain/stover) crops. For both species, the amounts of structural polysaccharides in the cell wall, measured as monomeric components (glucose and pentose), decreased during grain fill but remained unchanged thereafter with maize biomass possessing slightly higher amounts than sorghum. In conclusion, availability of carbohydrates in maize and sorghum highlights the potential for developing energy-rich dedicated biofuel or dual-purpose (grain/stover) crops.« less

Stover composition in maize and sorghum reveals remarkable genetic variation and plasticity for carbohydrate accumulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sekhon, Rajandeep S.; Breitzman, Matthew W.; Silva, Renato R.

Carbohydrates stored in vegetative organs, particularly stems, of grasses are a very important source of energy. We examined carbohydrate accumulation in adult sorghum and maize hybrids with distinct phenology and different end uses (grain, silage, sucrose or sweetness in stalk juice, and biomass). Remarkable variation was observed for nonstructural carbohydrates and structural polysaccharides during three key developmental stages both between and within hybrids developed for distinct end use in both species. At the onset of the reproductive phase (average 65 days after planting, DAP), a wide range for accumulation of non-structural carbohydrates (free glucose and sucrose combined), was observed inmore » internodes of maize (11-24%) and sorghum (7-36%) indicating substantial variation for transient storage of excess photosynthate during periods of low grain or vegetative sink strength. Remobilization of these reserves for supporting grain fill or vegetative growth was evident from lower amounts in maize (8-19%) and sorghum (9-27%) near the end of the reproductive period (average 95 DAP). At physiological maturity of grain hybrids (average 120 DAP), amounts of these carbohydrates were generally unchanged in maize (9-21%) and sorghum (16-27%) suggesting a loss of photosynthetic assimilation due to weakening sink demand. Nonetheless, high amounts of non-structural carbohydrates at maturity even in grain maize and sorghum (15-18%) highlight the potential for developing dual-purpose (grain/stover) crops. For both species, the amounts of structural polysaccharides in the cell wall, measured as monomeric components (glucose and pentose), decreased during grain fill but remained unchanged thereafter with maize biomass possessing slightly higher amounts than sorghum. In conclusion, availability of carbohydrates in maize and sorghum highlights the potential for developing energy-rich dedicated biofuel or dual-purpose (grain/stover) crops.« less

Carbohydrate utilization and metabolism is highly differentiated in Agaricus bisporus

PubMed Central

2013-01-01

Background Agaricus bisporus is commercially grown on compost, in which the available carbon sources consist mainly of plant-derived polysaccharides that are built out of various different constituent monosaccharides. The major constituent monosaccharides of these polysaccharides are glucose, xylose, and arabinose, while smaller amounts of galactose, glucuronic acid, rhamnose and mannose are also present. Results In this study, genes encoding putative enzymes from carbon metabolism were identified and their expression was studied in different growth stages of A. bisporus. We correlated the expression of genes encoding plant and fungal polysaccharide modifying enzymes identified in the A. bisporus genome to the soluble carbohydrates and the composition of mycelium grown compost, casing layer and fruiting bodies. Conclusions The compost grown vegetative mycelium of A. bisporus consumes a wide variety of monosaccharides. However, in fruiting bodies only hexose catabolism occurs, and no accumulation of other sugars was observed. This suggests that only hexoses or their conversion products are transported from the vegetative mycelium to the fruiting body, while the other sugars likely provide energy for growth and maintenance of the vegetative mycelium. Clear correlations were found between expression of the genes and composition of carbohydrates. Genes encoding plant cell wall polysaccharide degrading enzymes were mainly expressed in compost-grown mycelium, and largely absent in fruiting bodies. In contrast, genes encoding fungal cell wall polysaccharide modifying enzymes were expressed in both fruiting bodies and vegetative mycelium, but different gene sets were expressed in these samples. PMID:24074284

Effects of varying dietary carbohydrate levels on growth performance, body composition and liver histology of Malaysian mahseer fingerlings (Tor tambroides).

PubMed

Ishak, Sairatul Dahlianis; Kamarudin, Mohd Salleh; Ramezani-Fard, Ehsan; Saad, Che Roos; Yusof, Yus Aniza

2016-07-01

We investigated the effects of four iso-nitrogenous (40% crude protein) and iso-caloric (17.6 kJ g(-1)) diets with different dietary carbohydrate levels (15%, 20%, 25% and 30%) on the growth performance, feed utilization efficiency, body composition and liver histology of Malaysian mahseer (Tor tambroides) fingerlings in a 10-week feeding trial. Fish (initial weight of 0.8?0.1 g; initial total length 4.2?0.1 cm) were fed twice daily at 4% body mass. Dietary carbohydrate level had significant effects (P<0.05) on weight gain, SGR (specific growth rate), FCR (feed conversion rate), PER (protein efficiency rate), survival percentage and all nutrient retention values (PRV, LRV, CRV, ERV). Protein, carbohydrate and gross energy composition of the fish body were also significantly differed (P<0.05) among treatments. Liver histology showed mild hepatic steatosis and hypertrophy for fishes receiving a higher dietary carbohydrate inclusion. In general, treatments with 20% and 25% dietary carbohydrate levels produced better growth results compared to the rest of the treatments. Using a second-order polynomial regression analysis model, the optimal dietary carbohydrate level of 23.4% was estimated for mahseer fingerlings. ?

Natural acetylation impacts carbohydrate recovery during deconstruction of Populus trichocarpa wood

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Amanda M.; Kim, Hoon; Ralph, John

Significant variation in the inherent degree of acetylation naturally exists in the xylem cell walls of Populus trichocarpa. During pretreatment, endogenous acetate hydrolyzes to acetic acid that can subsequently catalyze the breakdown of poplar wood, increasing the efficiency of biomass pretreatment. Poplar genotypes varying in cell wall composition were pretreated in 0.3% H 2SO 4 in non-isothermal batch reactors. Acetic acid released from the wood was positively related to sugar release during pretreatment ( R ≥ 0.9), and inversely proportional to the lignin content of the poplar wood ( R = 0.6). There is significant variation in wood chemistry amongmore » P. trichocarpa genotypes. As a result, this study elucidated patterns of cell wall deconstruction and clearly links carbohydrate solubilization to acetate release. Tailoring biomass feedstocks for acetate release could enhance pretreatment efficiencies.« less

Natural acetylation impacts carbohydrate recovery during deconstruction of Populus trichocarpa wood

DOE PAGES

Johnson, Amanda M.; Kim, Hoon; Ralph, John; ...

2017-02-23

Significant variation in the inherent degree of acetylation naturally exists in the xylem cell walls of Populus trichocarpa. During pretreatment, endogenous acetate hydrolyzes to acetic acid that can subsequently catalyze the breakdown of poplar wood, increasing the efficiency of biomass pretreatment. Poplar genotypes varying in cell wall composition were pretreated in 0.3% H 2SO 4 in non-isothermal batch reactors. Acetic acid released from the wood was positively related to sugar release during pretreatment ( R ≥ 0.9), and inversely proportional to the lignin content of the poplar wood ( R = 0.6). There is significant variation in wood chemistry amongmore » P. trichocarpa genotypes. As a result, this study elucidated patterns of cell wall deconstruction and clearly links carbohydrate solubilization to acetate release. Tailoring biomass feedstocks for acetate release could enhance pretreatment efficiencies.« less

Carbohydrate Content and Enzyme Metabolism in Developing Canola Siliques.

PubMed Central

King, S. P.; Lunn, J. E.; Furbank, R. T.

1997-01-01

Little biochemical information is available on carbohydrate metabolism in developing canola (Brassica napus L.) silique (pod) wall and seed tissues. This research examines the carbohydrate contents and sucrose (Suc) metabolic enzyme activities in different aged silique wall and seed tissues during oil filling. The silique wall partitioned photosynthate into Suc over starch and predominantly accumulated hexose. The silique wall hexose content and soluble acid invertase activity rapidly fell as embryos progressed from the early- to late-cotyledon developmental stages. A similar trend was not evident for alkaline invertase, Suc synthase (SuSy), and Suc-phosphate synthase. Silique wall SuSy activities were much higher than source leaves at all times and may serve to supply the substrate for secondary cell wall thickening. In young seeds starch was the predominant accumulated carbohydrate over the sampled developmental range. Seed hexose levels dropped as embryos developed from the early- to midcotyledon stage. Hexose and starch were localized to the testa or liquid endosperm, whereas Suc was evenly distributed among seed components. With the switch to oil accumulation, seed SuSy activity increased by 3.6-fold and soluble acid invertase activity decreased by 76%. These data provide valuable baseline knowledge for the genetic manipulation of canola seed carbon partitioning. PMID:12223695

Carbohydrate Content and Enzyme Metabolism in Developing Canola Siliques.

PubMed

King, S. P.; Lunn, J. E.; Furbank, R. T.

1997-05-01

Little biochemical information is available on carbohydrate metabolism in developing canola (Brassica napus L.) silique (pod) wall and seed tissues. This research examines the carbohydrate contents and sucrose (Suc) metabolic enzyme activities in different aged silique wall and seed tissues during oil filling. The silique wall partitioned photosynthate into Suc over starch and predominantly accumulated hexose. The silique wall hexose content and soluble acid invertase activity rapidly fell as embryos progressed from the early- to late-cotyledon developmental stages. A similar trend was not evident for alkaline invertase, Suc synthase (SuSy), and Suc-phosphate synthase. Silique wall SuSy activities were much higher than source leaves at all times and may serve to supply the substrate for secondary cell wall thickening. In young seeds starch was the predominant accumulated carbohydrate over the sampled developmental range. Seed hexose levels dropped as embryos developed from the early- to midcotyledon stage. Hexose and starch were localized to the testa or liquid endosperm, whereas Suc was evenly distributed among seed components. With the switch to oil accumulation, seed SuSy activity increased by 3.6-fold and soluble acid invertase activity decreased by 76%. These data provide valuable baseline knowledge for the genetic manipulation of canola seed carbon partitioning.

Use of prebiotic carbohydrate as wall material on lime essential oil microparticles.

PubMed

Campelo, Pedro Henrique; Figueiredo, Jayne de Abreu; Domingues, Rosana Zacarias; Fernandes, Regiane Victória de Barros; Botrel, Diego Alvarenga; Borges, Soraia Vilela

2017-09-01

The aim of this work was to study the use of different prebiotic biopolymers in lime essential oil microencapsulation. Whey protein isolate, inulin and oligofructose biopolymers were used. The addition of prebiotic biopolymers reduced emulsion viscosity, although it produced larger droplet sizes (0.31-0.32 µm). Moisture values (2.94-3.13 g/100 g dry solids) and water activity (0.152-0.185) were satisfactory, being within the appropriate range for powdered food quality. Total oil content, limonene retention values and antioxidant activity of the microparticles containing essential oil decreased in the presence of the carbohydrates. The addition of prebiotic biopolymers reduced the microparticle thermal stability. X-ray diffraction confirmed the amorphous characteristic of the microparticles and the interaction of the essential oil with the wall material. The presence of prebiotic biopolymers can be a good alternative for lime essential oil microparticles, mainly using fibre that has a functional food appeal and can improve consumer health.

Role of Pathogen-Derived Cell Wall Carbohydrates and Prostaglandin E2 in Immune Response and Suppression of Fish Immunity by the Oomycete Saprolegnia parasitica

PubMed Central

Belmonte, Rodrigo; Wang, Tiehui; Duncan, Gary J.; Skaar, Ida; Mélida, Hugo; Bulone, Vincent; van West, Pieter

2014-01-01

Saprolegnia parasitica is a freshwater oomycete that is capable of infecting several species of fin fish. Saprolegniosis, the disease caused by this microbe, has a substantial impact on Atlantic salmon aquaculture. No sustainable treatment against saprolegniosis is available, and little is known regarding the host response. In this study, we examined the immune response of Atlantic salmon to S. parasitica infection and to its cell wall carbohydrates. Saprolegnia triggers a strong inflammatory response in its host (i.e., induction of interleukin-1β1 [IL-1β1], IL-6, and tumor necrosis factor alpha), while severely suppressing the expression of genes associated with adaptive immunity in fish, through downregulation of T-helper cell cytokines, antigen presentation machinery, and immunoglobulins. Oomycete cell wall carbohydrates were recognized by fish leukocytes, triggering upregulation of genes involved in the inflammatory response, similar to what is observed during infection. Our data suggest that S. parasitica is capable of producing prostaglanding E2 (PGE2) in vitro, a metabolite not previously shown to be produced by oomycetes, and two proteins with homology to vertebrate enzymes known to play a role in prostaglandin biosynthesis have been identified in the oomycete genome. Exogenous PGE2 was shown to increase the inflammatory response in fish leukocytes incubated with cell wall carbohydrates while suppressing genes involved in cellular immunity (gamma interferon [IFN-γ] and the IFN-γ-inducible protein [γ-IP]). Inhibition of S. parasitica zoospore germination and mycelial growth by two cyclooxygenase inhibitors (aspirin and indomethacin) also suggests that prostaglandins may be involved in oomycete development. PMID:25114122

Carbohydrate-active enzymes from the zygomycete fungus Rhizopus oryzae: a highly specialized approach to carbohydrate degradation depicted at genome level

PubMed Central

2011-01-01

Background Rhizopus oryzae is a zygomycete filamentous fungus, well-known as a saprobe ubiquitous in soil and as a pathogenic/spoilage fungus, causing Rhizopus rot and mucomycoses. Results Carbohydrate Active enzyme (CAZy) annotation of the R. oryzae identified, in contrast to other filamentous fungi, a low number of glycoside hydrolases (GHs) and a high number of glycosyl transferases (GTs) and carbohydrate esterases (CEs). A detailed analysis of CAZy families, supported by growth data, demonstrates highly specialized plant and fungal cell wall degrading abilities distinct from ascomycetes and basidiomycetes. The specific genomic and growth features for degradation of easily digestible plant cell wall mono- and polysaccharides (starch, galactomannan, unbranched pectin, hexose sugars), chitin, chitosan, β-1,3-glucan and fungal cell wall fractions suggest specific adaptations of R. oryzae to its environment. Conclusions CAZy analyses of the genome of the zygomycete fungus R. oryzae and comparison to ascomycetes and basidiomycete species revealed how evolution has shaped its genetic content with respect to carbohydrate degradation, after divergence from the Ascomycota and Basidiomycota. PMID:21241472

Versatile derivatives of carbohydrate-binding modules for imaging of complex carbohydrates approaching the molecular level of resolution.

PubMed

Ding, Shi-You; Xu, Qi; Ali, Mursheda K; Baker, John O; Bayer, Edward A; Barak, Yoav; Lamed, Raphael; Sugiyama, Junji; Rumbles, Garry; Himmel, Michael E

2006-10-01

The innate binding specificity of different carbohydrate-binding modules (CBMs) offers a versatile approach for mapping the chemistry and structure of surfaces that contain complex carbohydrates. We have employed the distinct recognition properties of a double His-tagged recombinant CBM tagged with semiconductor quantum dots for direct imaging of crystalline cellulose at the molecular level of resolution, using transmission and scanning transmission electron microscopy. In addition, three different types of CBMs from families 3, 6, and 20 that exhibit different carbohydrate specificities were each fused with either green fluorescent protein (GFP) or red fluorescent protein (RFP) and employed for double-labeling fluorescence microscopy studies of primary cell walls and various mixtures of complex carbohydrate target molecules. CBM probes can be used for characterizing both native complex carbohydrates and engineered biomaterials.

Binding of Human GII.4 Norovirus Virus-Like Particles to Carbohydrates of Romaine Lettuce Leaf Cell Wall Materials

PubMed Central

Esseili, Malak A.

2012-01-01

Norovirus (NoV) genogroup II genotype 4 (GII.4) strains are the dominant cause of the majority of food-borne outbreaks, including those that involve leafy greens, such as lettuce. Since human NoVs use carbohydrates of histo-blood group antigens as receptors/coreceptors, we examined the role of carbohydrates in the attachment of NoV to lettuce leaves by using virus-like particles (VLPs) of a human NoV/GII.4 strain. Immunofluorescence analysis showed that the VLPs attached to the leaf surface, especially to cut edges, stomata, and along minor veins. Binding was quantified using enzyme-linked immunosorbent assay (ELISA) performed on cell wall materials (CWM) from innermost younger leaves and outermost lamina of older leaves. The binding to CWM of older leaves was significantly (P < 0.05) higher (1.5- to 2-fold) than that to CWM of younger leaves. Disrupting the carbohydrates of CWM or porcine gastric mucin (PGM) (a carbohydrate control) using 100 mM sodium periodate (NaIO4) significantly decreased the binding an average of 17% in younger leaves, 43% in older leaves, and 92% for PGM. In addition, lectins recognizing GalNAc, GlcNAc, and sialic acid at 100 μg/ml significantly decreased the binding an average of 41%, 33%, and 20% on CWM of older leaves but had no effect on younger leaves. Lectins recognizing α-d-Gal, α-d-Man/α-d-Glc, and α-l-Fuc showed significant inhibition on CWM of older leaves as well as that of younger leaves. All lectins, except for the lectin recognizing α-d-Gal, significantly inhibited NoV VLP binding to PGM. Collectively, our results indicate that NoV VLPs bind to lettuce CWM by utilizing multiple carbohydrate moieties. This binding may enhance virus persistence on the leaf surface and prevent effective decontamination. PMID:22138991

Compositional evaluation of selected agro-industrial wastes as valuable sources for the recovery of complex carbohydrates.

PubMed

Vojvodić, Aleksandra; Komes, Draženka; Vovk, Irena; Belščak-Cvitanović, Ana; Bušić, Arijana

2016-11-01

Re-utilization of various agro-industrial wastes is of growing importance from many aspects. Considering the variety and complexity of such materials, compositional data and compliant methodology is still undergoing many updates and improvements. Present study evaluated sugar beet pulp (SBP), walnut shell (WS), cocoa bean husk (CBH), onion peel (OP) and pea pods (PP) as potentially valuable materials for carbohydrate recovery. Macrocomponent analyses revealed carbohydrate fraction as the most abundant, dominating in dietary fibres. Upon complete acid hydrolysis of sample alcohol insoluble residues, developed procedures of high performance thin-layer chromatography (HPTLC) and high performance liquid chromatography (HPLC) coupled with 3-methyl-1-phenyl-2-pyrazolin-5-one pre-column derivatization (PMP-derivatization) were used for carbohydrate monomeric composition determination. HPTLC exhibited good qualitative features useful for multi-sample rapid analysis, while HPLC superior separation and quantification characteristics. Distinctive monomeric patterns were obtained among samples. OP, SBP and CBH, due to the high galacturonic acid content (20.81%, 13.96% and 6.90% dry matter basis, respectively), may be regarded as pectin sources, while WS and PP as materials abundant in xylan-rich hemicellulose (total xylan content 15.53%, 9.63% dry matter basis, respectively). Present study provides new and valuable compositional data for different plant residual materials and a reference for the application of established methodology. Copyright © 2016 Elsevier Ltd. All rights reserved.

Carbohydrates as indicators of biogeochemical processes

NASA Astrophysics Data System (ADS)

Lazareva, E. V.; Romankevich, E. A.

2012-05-01

A method is presented to study the carbohydrate composition of marine objects involved into sedimento- and diagenesis (plankton, particulate matter, benthos, and bottom sediments). The analysis of the carbohydrates is based upon the consecutive separation of their fractions with different solvents (water, alkali, and acid). The ratio of the carbohydrate fractions allows one to evaluate the lability of the carbohydrate complex. It is also usable as an indicator of the biogeochemical processes in the ocean, as well of the genesis and the degree of conversion of organic matter in the bottom sediments and nodules. The similarity in the monosaccharide composition is shown for dissolved organic matter and aqueous and alkaline fractions of seston and particulate matter.

Composition of the carbohydrate granules of the cyanobacterium, Cyanothece sp. strain ATCC 51142

NASA Technical Reports Server (NTRS)

Schneegurt, M. A.; Sherman, D. M.; Sherman, L. A.; Mitchell, C. A. (Principal Investigator)

1997-01-01

Cyanothece sp. strain ATCC 51142 is an aerobic, unicellular, diazotrophic cyanobacterium that temporally separates O2-sensitive N2 fixation from oxygenic photosynthesis. The energy and reducing power needed for N2 fixation appears to be generated by an active respiratory apparatus that utilizes the contents of large interthylakoidal carbohydrate granules. We report here on the carbohydrate and protein composition of the granules of Cyanothece sp. strain ATCC 51142. The carbohydrate component is a glucose homopolymer with branches every nine residues and is chemically identical to glycogen. Granule-associated protein fractions showed temporal changes in the number of proteins and their abundance during the metabolic oscillations observed under diazotrophic conditions. There also were temporal changes in the protein pattern of the granule-depleted supernatant fractions from diazotrophic cultures. None of the granule-associated proteins crossreacted with antisera directed against several glycogen-metabolizing enzymes or nitrogenase, although these proteins were tentatively identified in supernatant fractions. It is suggested that the granule-associated proteins are structural proteins required to maintain a complex granule architecture.

Seismic Behaviour of Composite Steel Fibre Reinforced Concrete Shear Walls

NASA Astrophysics Data System (ADS)

Boita, Ioana-Emanuela; Dan, Daniel; Stoian, Valeriu

2017-10-01

In this paper is presented an experimental study conducted at the “Politehnica” University of Timisoara, Romania. This study provides results from a comprehensive experimental investigation on the behaviour of composite steel fibre reinforced concrete shear walls (CSFRCW) with partially or totally encased profiles. Two experimental composite steel fibre reinforced concrete walls (CSFRCW) and, as a reference specimen, a typical reinforced concrete shear wall (RCW), (without structural reinforcement), were fabricated and tested under constant vertical load and quasi-static reversed cyclic lateral loads, in displacement control. The tests were performed until failure. The tested specimens were designed as 1:3 scale steel-concrete composite elements, representing a three storeys and one bay element from the base of a lateral resisting system made by shear walls. Configuration/arrangement of steel profiles in cross section were varied within the specimens. The main objective of this research consisted in identifying innovative solutions for composite steel-concrete shear walls with enhanced performance, as steel fibre reinforced concrete which was used in order to replace traditional reinforced concrete. A first conclusion was that replacing traditional reinforcement with steel fibre changes the failure mode of the elements, as from a flexural mode, in case of element RCW, to a shear failure mode for CSFRCW. The maximum lateral force had almost similar values but test results indicated an improvement in cracking response, and a decrease in ductility. The addition of steel fibres in the concrete mixture can lead to an increase of the initial cracking force, and can change the sudden opening of a crack in a more stable process.

Carbohydrate terminology and classification.

PubMed

Cummings, J H; Stephen, A M

2007-12-01

Dietary carbohydrates are a group of chemically defined substances with a range of physical and physiological properties and health benefits. As with other macronutrients, the primary classification of dietary carbohydrate is based on chemistry, that is character of individual monomers, degree of polymerization (DP) and type of linkage (alpha or beta), as agreed at the Food and Agriculture Organization/World Health Organization Expert Consultation in 1997. This divides carbohydrates into three main groups, sugars (DP 1-2), oligosaccharides (short-chain carbohydrates) (DP 3-9) and polysaccharides (DP> or =10). Within this classification, a number of terms are used such as mono- and disaccharides, polyols, oligosaccharides, starch, modified starch, non-starch polysaccharides, total carbohydrate, sugars, etc. While effects of carbohydrates are ultimately related to their primary chemistry, they are modified by their physical properties. These include water solubility, hydration, gel formation, crystalline state, association with other molecules such as protein, lipid and divalent cations and aggregation into complex structures in cell walls and other specialized plant tissues. A classification based on chemistry is essential for a system of measurement, predication of properties and estimation of intakes, but does not allow a simple translation into nutritional effects since each class of carbohydrate has overlapping physiological properties and effects on health. This dichotomy has led to the use of a number of terms to describe carbohydrate in foods, for example intrinsic and extrinsic sugars, prebiotic, resistant starch, dietary fibre, available and unavailable carbohydrate, complex carbohydrate, glycaemic and whole grain. This paper reviews these terms and suggests that some are more useful than others. A clearer understanding of what is meant by any particular word used to describe carbohydrate is essential to progress in translating the growing knowledge of the

Supramolecular Interactions in Secondary Plant Cell Walls: Effect of Lignin Chemical Composition Revealed with the Molecular Theory of Solvation.

PubMed

Silveira, Rodrigo L; Stoyanov, Stanislav R; Gusarov, Sergey; Skaf, Munir S; Kovalenko, Andriy

2015-01-02

Plant biomass recalcitrance, a major obstacle to achieving sustainable production of second generation biofuels, arises mainly from the amorphous cell-wall matrix containing lignin and hemicellulose assembled into a complex supramolecular network that coats the cellulose fibrils. We employed the statistical-mechanical, 3D reference interaction site model with the Kovalenko-Hirata closure approximation (or 3D-RISM-KH molecular theory of solvation) to reveal the supramolecular interactions in this network and provide molecular-level insight into the effective lignin-lignin and lignin-hemicellulose thermodynamic interactions. We found that such interactions are hydrophobic and entropy-driven, and arise from the expelling of water from the mutual interaction surfaces. The molecular origin of these interactions is carbohydrate-π and π-π stacking forces, whose strengths are dependent on the lignin chemical composition. Methoxy substituents in the phenyl groups of lignin promote substantial entropic stabilization of the ligno-hemicellulosic matrix. Our results provide a detailed molecular view of the fundamental interactions within the secondary plant cell walls that lead to recalcitrance.

Cell wall composition throughout development for the model grass Brachypodium distachyon

PubMed Central

Rancour, David M.; Marita, Jane M.; Hatfield, Ronald D.

2012-01-01

Temperate perennial grasses are important worldwide as a livestock nutritive energy source and a potential feedstock for lignocellulosic biofuel production. The annual temperate grass Brachypodium distachyon has been championed as a useful model system to facilitate biological research in agriculturally important temperate forage grasses based on phylogenetic relationships. To physically corroborate genetic predictions, we determined the chemical composition profiles of organ-specific cell walls throughout the development of two common diploid accessions of Brachypodium distachyon, Bd21-3 and Bd21. Chemical analysis was performed on cell walls isolated from distinct organs (i.e., leaves, sheaths, stems, and roots) at three developmental stages of (1) 12-day seedling, (2) vegetative-to-reproductive transition, and (3) mature seed fill. In addition, we have included cell wall analysis of embryonic callus used for genetic transformations. Composition of cell walls based on components lignin, hydroxycinnamates, uronosyls, neutral sugars, and protein suggests that Brachypodium distachyon is similar chemically to agriculturally important forage grasses. There were modest compositional differences in hydroxycinnamate profiles between accessions Bd21-3 and Bd21. In addition, when compared to agronomical important C3 grasses, more mature Brachypodium stem cell walls have a relative increase in glucose of 48% and a decrease in lignin of 36%. Though differences exist between Brachypodium and agronomical important C3 grasses, Brachypodium distachyon should be still a useful model system for genetic manipulation of cell wall composition to determine the impact upon functional characteristics such as rumen digestibility or energy conversion efficiency for bioenergy production. PMID:23227028

Role of pathogen-derived cell wall carbohydrates and prostaglandin E2 in immune response and suppression of fish immunity by the oomycete Saprolegnia parasitica.

PubMed

Belmonte, Rodrigo; Wang, Tiehui; Duncan, Gary J; Skaar, Ida; Mélida, Hugo; Bulone, Vincent; van West, Pieter; Secombes, Christopher J

2014-11-01

Saprolegnia parasitica is a freshwater oomycete that is capable of infecting several species of fin fish. Saprolegniosis, the disease caused by this microbe, has a substantial impact on Atlantic salmon aquaculture. No sustainable treatment against saprolegniosis is available, and little is known regarding the host response. In this study, we examined the immune response of Atlantic salmon to S. parasitica infection and to its cell wall carbohydrates. Saprolegnia triggers a strong inflammatory response in its host (i.e., induction of interleukin-1β1 [IL-1β1], IL-6, and tumor necrosis factor alpha), while severely suppressing the expression of genes associated with adaptive immunity in fish, through downregulation of T-helper cell cytokines, antigen presentation machinery, and immunoglobulins. Oomycete cell wall carbohydrates were recognized by fish leukocytes, triggering upregulation of genes involved in the inflammatory response, similar to what is observed during infection. Our data suggest that S. parasitica is capable of producing prostaglandin [corrected] E2 (PGE2) in vitro, a metabolite not previously shown to be produced by oomycetes, and two proteins with homology to vertebrate enzymes known to play a role in prostaglandin biosynthesis have been identified in the oomycete genome. Exogenous PGE2 was shown to increase the inflammatory response in fish leukocytes incubated with cell wall carbohydrates while suppressing genes involved in cellular immunity (gamma interferon [IFN-γ] and the IFN-γ-inducible protein [γ-IP]). Inhibition of S. parasitica zoospore germination and mycelial growth by two cyclooxygenase inhibitors (aspirin and indomethacin) also suggests that prostaglandins may be involved in oomycete development. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

The Effects of Breakfast Consumption and Composition on Metabolic Wellness with a Focus on Carbohydrate Metabolism.

PubMed

Maki, Kevin C; Phillips-Eakley, Alyssa K; Smith, Kristen N

2016-05-01

Findings from epidemiologic studies indicate that there are associations between breakfast consumption and a lower risk of type 2 diabetes mellitus (T2DM) and metabolic syndrome, prompting interest in the influence of breakfast on carbohydrate metabolism and indicators of T2DM risk. The objective of this review was to summarize the available evidence from randomized controlled trials assessing the impact of breakfast on variables related to carbohydrate metabolism and metabolic wellness. Consuming compared with skipping breakfast appeared to improve glucose and insulin responses throughout the day. Breakfast composition may also be important. Dietary patterns high in rapidly available carbohydrate were associated with elevated T2DM risk. Therefore, partial replacement of rapidly available carbohydrate with other dietary components, such as whole grains and cereal fibers, proteins, and unsaturated fatty acids (UFAs), at breakfast may be a useful strategy for producing favorable metabolic outcomes. Consumption of fermentable and viscous dietary fibers at breakfast lowers glycemia and insulinemia. Fermentable fibers likely act through enhancing insulin sensitivity later in the day, and viscous fibers have an acute effect to slow the rate of carbohydrate absorption. Partially substituting protein for rapidly available carbohydrate enhances satiety and diet-induced thermogenesis, and also favorably affects lipoprotein lipids and blood pressure. Partially substituting UFA for carbohydrate has been associated with improved insulin sensitivity, lipoprotein lipids, and blood pressure. Overall, the available evidence suggests that consuming breakfast foods high in whole grains and cereal fiber, while limiting rapidly available carbohydrate, is a promising strategy for metabolic health promotion. © 2016 American Society for Nutrition.

Floral nectar production and carbohydrate composition and the structure of receptacular nectaries in the invasive plant Bunias orientalis L. (Brassicaceae).

PubMed

Denisow, Bożena; Masierowska, Marzena; Antoń, Sebastian

2016-11-01

The data relating to the nectaries and nectar secretion in invasive Brassicacean taxa are scarce. In the present paper, the nectar production and nectar carbohydrate composition as well as the morphology, anatomy and ultrastructure of the floral nectaries in Bunias orientalis were investigated. Nectary glands were examined using light, fluorescence, scanning electron and transmission electron microscopy. The quantities of nectar produced by flowers and total sugar mass in nectar were relatively low. Total nectar carbohydrate production per 10 flowers averaged 0.3 mg. Nectar contained exclusively glucose (G) and fructose (F) with overall G/F ratio greater than 1. The flowers of B. orientalis have four nectaries placed at the base of the ovary. The nectarium is intermediate between two nectary types: the lateral and median nectary type (lateral and median glands stay separated) and the annular nectary type (both nectaries are united into one). Both pairs of glands represent photosynthetic type and consist of epidermis and glandular tissue. However, they differ in their shape, size, secretory activity, dimensions of epidermal and parenchyma cells, thickness of secretory parenchyma, phloem supply, presence of modified stomata and cuticle ornamentation. The cells of nectaries contain dense cytoplasm, plastids with starch grains and numerous mitochondria. Companion cells of phloem lack cell wall ingrowths. The ultrastructure of secretory cells indicates an eccrine mechanism of secretion. Nectar is exuded throughout modified stomata.

Boron Deficiency in Trifoliate Orange Induces Changes in Pectin Composition and Architecture of Components in Root Cell Walls.

PubMed

Wu, Xiuwen; Riaz, Muhammad; Yan, Lei; Du, Chenqing; Liu, Yalin; Jiang, Cuncang

2017-01-01

Boron (B) is a micronutrient indispensable for citrus and B deficiency causes a considerable loss of productivity and quality in China. However, studies on pectin composition and architecture of cell wall components in trifoliate orange roots under B deficiency condition are not sufficient. In this study, we investigated the alteration in pectin characteristics and the architecture of cell wall components in trifoliate orange [ Poncirus trifoliata (L.) Raf.] roots under B starvation. The results showed that B-deficient roots resulted in a significant enlargement of root tips and an obvious decrease in cell wall B and uronic acid content in Na 2 CO 3 -soluble pectin compared with B-adequate roots. Meanwhile, they showed a decrease of 2-keto-3-deoxyoctanoic acid in CDTA-soluble and Na 2 CO 3 -soluble pectin in cell walls, while the degree of methylation (DM) of CDTA-soluble pectin was significantly increased under B deficiency. Transmission electron microscope (TEM) micrographs of B deficient plants showed a distinct thickening of the cell walls, with the thickness 1.82 times greater than that of control plant roots. The results from Fourier-transform infrared spectroscopy (FTIR) showed that B deficiency changed the mode of hydrogen bonding between protein and carbohydrates (cellulose and hemicellulose). The FTIR spectra exhibited a destroyed protein structure and accumulation of wax and cellulose in the cell walls under B starvation. The 13 C nuclear magnetic resonance ( 13 C-NMR) spectra showed that B starvation changed the organic carbon structure of cell walls, and enhanced the contents of amino acid, cellulose, phenols, and lignin in the cell wall. The results reveal that the swelling and weakened structural integrity of cell walls, which induced by alteration on the network of pectin and cell wall components and structure in B-deficient roots, could be a major cause of occurrence of the rapid interruption of growth and significantly enlarged root tips in

The statolith compartment in Chara rhizoids contains carbohydrate and protein.

PubMed

Wang-Cahill, F; Kiss, J Z

1995-02-01

In contrast to higher plants, the alga Chara has rhizoids with single membrane-bound compartments that function as statoliths in gravity perception. Previous work has demonstrated that these statoliths contain barium sulfate crystals. In this study, we show that statoliths in Chara rhizoids react with a Coomassie Brilliant Blue cytochemical stain for proteins. While statoliths did not react with silver methenamine carbohydrate cytochemistry, the monoclonal antibody CCRC-M2, which is against a carbohydrate (sycamore-maple rhamnogalacturonan I), labeled the statolith compartment. These results demonstrate that in addition to barium sulfate, statoliths in Chara rhizoids have an organic matrix that consists of protein and carbohydrate moieties. Since the statoliths were silver methenamine negative, the carbohydrate in this compartment could be a 3-linked polysaccharide. CCRC-M2 also labeled Golgi cisternae, Golgi-associated vesicles, apical vesicles, and cell walls in the rhizoids. The specificity of CCRC-M2 immunolabeling was verified by several control experiments, including the demonstration that labeling was abolished when the antibody was preabsorbed with its antigen. Since in this and a previous study (John Z. Kiss and L. Andrew Staehelin, American Journal of Botany 80: 273-282, 1993) antibodies against higher plant carbohydrates crossreacted with cell walls of Chara in a specific manner, Characean algae may be a useful model system in biochemical and molecular studies of cell walls.

The statolith compartment in Chara rhizoids contains carbohydrate and protein

NASA Technical Reports Server (NTRS)

Wang-Cahill, F.; Kiss, J. Z.

1995-01-01

In contrast to higher plants, the alga Chara has rhizoids with single membrane-bound compartments that function as statoliths in gravity perception. Previous work has demonstrated that these statoliths contain barium sulfate crystals. In this study, we show that statoliths in Chara rhizoids react with a Coomassie Brilliant Blue cytochemical stain for proteins. While statoliths did not react with silver methenamine carbohydrate cytochemistry, the monoclonal antibody CCRC-M2, which is against a carbohydrate (sycamore-maple rhamnogalacturonan I), labeled the statolith compartment. These results demonstrate that in addition to barium sulfate, statoliths in Chara rhizoids have an organic matrix that consists of protein and carbohydrate moieties. Since the statoliths were silver methenamine negative, the carbohydrate in this compartment could be a 3-linked polysaccharide. CCRC-M2 also labeled Golgi cisternae, Golgi-associated vesicles, apical vesicles, and cell walls in the rhizoids. The specificity of CCRC-M2 immunolabeling was verified by several control experiments, including the demonstration that labeling was abolished when the antibody was preabsorbed with its antigen. Since in this and a previous study (John Z. Kiss and L. Andrew Staehelin, American Journal of Botany 80: 273-282, 1993) antibodies against higher plant carbohydrates crossreacted with cell walls of Chara in a specific manner, Characean algae may be a useful model system in biochemical and molecular studies of cell walls.

Carbohydrate Microarray Technology Applied to High-Throughput Mapping of Plant Cell Wall Glycans Using Comprehensive Microarray Polymer Profiling (CoMPP).

PubMed

Kračun, Stjepan Krešimir; Fangel, Jonatan Ulrik; Rydahl, Maja Gro; Pedersen, Henriette Lodberg; Vidal-Melgosa, Silvia; Willats, William George Tycho

2017-01-01

Cell walls are an important feature of plant cells and a major component of the plant glycome. They have both structural and physiological functions and are critical for plant growth and development. The diversity and complexity of these structures demand advanced high-throughput techniques to answer questions about their structure, functions and roles in both fundamental and applied scientific fields. Microarray technology provides both the high-throughput and the feasibility aspects required to meet that demand. In this chapter, some of the most recent microarray-based techniques relating to plant cell walls are described together with an overview of related contemporary techniques applied to carbohydrate microarrays and their general potential in glycoscience. A detailed experimental procedure for high-throughput mapping of plant cell wall glycans using the comprehensive microarray polymer profiling (CoMPP) technique is included in the chapter and provides a good example of both the robust and high-throughput nature of microarrays as well as their applicability to plant glycomics.

Remobilization of toxic heavy metals adsorbed to bacterial wall-clay composites.

PubMed Central

Flemming, C A; Ferris, F G; Beveridge, T J; Bailey, G W

1990-01-01

Significant quantities of Ag(I), Cu(II), and Cr(III) were bound to isolated Bacillus subtilis 168 walls, Escherichia coli K-12 envelopes, kaolinite and smectite clays, and the corresponding organic material-clay aggregates (1:1, wt/wt). These sorbed metals were leached with HNO3, Ca(NO3)2, EDTA, fulvic acid, and lysozyme at several concentrations over 48 h at room temperature. The remobilization of the sorbed metals depended on the physical properties of the organic and clay surfaces and on the character and concentration of the leaching agents. In general, the order of remobilization of metals was Cr much less than Ag less than Cu. Cr was very stable in the wall, clay, and composite systems; pH 3.0, 500 microM EDTA, 120-ppm [mg liter-1] fulvic acid, and 160-ppm Ca remobilized less than 32% (wt/wt) of sorbed Cr. Ag (45 to 87%) and Cu (up to 100%) were readily removed by these agents. Although each leaching agent was effective at mobilizing certain metals, elevated Ca or acidic pH produced the greatest overall mobility. The organic chelators were less effective. Lysozyme digestion of Bacillus walls remobilized Cu from walls and Cu-wall-kaolinite composites, but Ag, Cr, and smectite partially inhibited enzyme activity, and the metals remained insoluble. The extent of metal remobilization was not always dependent on increasing concentrations of leaching agents; for example, Ag mobility decreased with some clays and some composites treated with high fulvic acid, EDTA, and lysozyme concentrations. Sometimes the organic material-clay composites reacted in a manner distinctly different from that of their individual counterparts; e.g., 25% less Cu was remobilized from wall- and envelope-smectite composites than from walls, envelopes, or smectite individually in 500 microM EDTA. Alternatively, treatment with 160-ppm Ca removed 1.5 to 10 times more Ag from envelope-kaolinite composites than from the individual components. The particle size of the deposited metal may account

Axial compression behavior and partial composite action of SC walls in safety-related nuclear facilities

NASA Astrophysics Data System (ADS)

Zhang, Kai

Steel-plate reinforced concrete (SC) composite walls typically consist of thick concrete walls with two exterior steel faceplates. The concrete core is sandwiched between the two steel faceplates, and the faceplates are attached to the concrete core using shear connectors, for example, ASTM A108 steel headed shear studs. The shear connectors and the concrete infill enhance the stability of the steel faceplates, and the faceplates serve as permanent formwork for concrete placement. SC composite walls were first introduced in the 1980's in Japan for nuclear power plant (NPP) structures. They are used in the new generation of nuclear power plants (GIII+) and being considered for small modular reactors (SMR) due to their structural efficiency, economy, safety, and construction speed. Steel faceplates can potentially undergo local buckling at certain locations of NPP structures where compressive forces are significant. The steel faceplates are usually thin (0.25 to 1.50 inches in Customary units, or 6.5 to 38 mm in SI units) to maintain economical and constructional efficiency, the geometric imperfections and locked-in stresses induced during construction make them more vulnerable to local buckling. Accidental thermal loading may also reduce the compressive strength and exacerbate the local buckling potential of SC composite walls. This dissertation presents the results from experimental and numerical investigations of the compressive behavior of SC composite walls at ambient and elevated temperatures. The results are used to establish a slenderness limit to prevent local buckling before yielding of the steel faceplates and to develop a design approach for calculating the compressive strength of SC composite walls with non-slender and slender steel faceplates at ambient and elevated temperatures. Composite action in SC walls is achieved by the embedment of shear connectors into the concrete core. The strength and stiffness of shear connectors govern the level of

Seismic Performance of Composite Shear Walls Constructed Using Recycled Aggregate Concrete and Different Expandable Polystyrene Configurations.

PubMed

Liu, Wenchao; Cao, Wanlin; Zhang, Jianwei; Qiao, Qiyun; Ma, Heng

2016-03-02

The seismic performance of recycled aggregate concrete (RAC) composite shear walls with different expandable polystyrene (EPS) configurations was investigated. Six concrete shear walls were designed and tested under cyclic loading to evaluate the effect of fine RAC in designing earthquake-resistant structures. Three of the six specimens were used to construct mid-rise walls with a shear-span ratio of 1.5, and the other three specimens were used to construct low-rise walls with a shear-span ratio of 0.8. The mid-rise and low-rise shear walls consisted of an ordinary recycled concrete shear wall, a composite wall with fine aggregate concrete (FAC) protective layer (EPS modules as the external insulation layer), and a composite wall with sandwiched EPS modules as the insulation layer. Several parameters obtained from the experimental results were compared and analyzed, including the load-bearing capacity, stiffness, ductility, energy dissipation, and failure characteristics of the specimens. The calculation formula of load-bearing capacity was obtained by considering the effect of FAC on composite shear walls as the protective layer. The damage process of the specimen was simulated using the ABAQUS Software, and the results agreed quite well with those obtained from the experiments. The results show that the seismic resistance behavior of the EPS module composite for shear walls performed better than ordinary recycled concrete for shear walls. Shear walls with sandwiched EPS modules had a better seismic performance than those with EPS modules lying outside. Although the FAC protective layer slightly improved the seismic performance of the structure, it undoubtedly slowed down the speed of crack formation and the stiffness degradation of the walls.

Seismic Performance of Composite Shear Walls Constructed Using Recycled Aggregate Concrete and Different Expandable Polystyrene Configurations

PubMed Central

Liu, Wenchao; Cao, Wanlin; Zhang, Jianwei; Qiao, Qiyun; Ma, Heng

2016-01-01

The seismic performance of recycled aggregate concrete (RAC) composite shear walls with different expandable polystyrene (EPS) configurations was investigated. Six concrete shear walls were designed and tested under cyclic loading to evaluate the effect of fine RAC in designing earthquake-resistant structures. Three of the six specimens were used to construct mid-rise walls with a shear-span ratio of 1.5, and the other three specimens were used to construct low-rise walls with a shear-span ratio of 0.8. The mid-rise and low-rise shear walls consisted of an ordinary recycled concrete shear wall, a composite wall with fine aggregate concrete (FAC) protective layer (EPS modules as the external insulation layer), and a composite wall with sandwiched EPS modules as the insulation layer. Several parameters obtained from the experimental results were compared and analyzed, including the load-bearing capacity, stiffness, ductility, energy dissipation, and failure characteristics of the specimens. The calculation formula of load-bearing capacity was obtained by considering the effect of FAC on composite shear walls as the protective layer. The damage process of the specimen was simulated using the ABAQUS Software, and the results agreed quite well with those obtained from the experiments. The results show that the seismic resistance behavior of the EPS module composite for shear walls performed better than ordinary recycled concrete for shear walls. Shear walls with sandwiched EPS modules had a better seismic performance than those with EPS modules lying outside. Although the FAC protective layer slightly improved the seismic performance of the structure, it undoubtedly slowed down the speed of crack formation and the stiffness degradation of the walls. PMID:28773274

Size-fractionated dissolved primary production and carbohydrate composition of the coccolithophore Emiliania huxleyi

NASA Astrophysics Data System (ADS)

Borchard, C.; Engel, A.

2014-11-01

Extracellular release (ER) by phytoplankton is the major source of fresh dissolved organic carbon (DOC) in marine ecosystems and accompanies primary production during all growth phases. Little is known, so far, on size and composition of released molecules, and to which extent ER occurs passively, by leakage, or actively, by exudation. Here, we report on ER by the widespread and bloom-forming coccolithophore Emiliania huxleyi grown under steady state conditions in phosphorus controlled chemostats (N : P = 29, growth rate of μ = 0.2 d-1). 14C incubations were accomplished to determine primary production (PP), comprised by particulate (PO14C) and dissolved organic carbon (DO14C), and the concentration and composition of particulate combined carbohydrates (pCCHO), and of high molecular weight (>1 kDa, HMW) dissolved combined carbohydrates (dCCHO) as major components of ER. Information on size distribution of ER products was obtained by investigating distinct size classes (<0.40 μm, <1000 kDa, <100 kDa and <10 kDa) of DO14C and HMW-dCCHO. Our results revealed relatively low ER during steady state growth, corresponding to ∼4.5% of primary production, and similar ER rates for all size classes. Acidic sugars had a significant share on freshly produced pCCHO as well as on HMW-dCCHO. While pCCHO and the smallest size (<10 kDa) fraction of HMW-dCCHO exhibited a similar sugar composition, dominated by high percentages of glucose (74-80 Mol%), the composition of HMW-dCCHO size-classes >10 kDa was significantly different with higher Mol% of arabinose. Mol% of acidic sugars increased and Mol% glucose decreased with increasing size of HMW-dCCHO. We conclude that larger polysaccharides follow different production and release pathways than smaller molecules, potentially serving distinct ecological and biogeochemical functions.

Genetic resources for maize cell wall biology.

PubMed

Penning, Bryan W; Hunter, Charles T; Tayengwa, Reuben; Eveland, Andrea L; Dugard, Christopher K; Olek, Anna T; Vermerris, Wilfred; Koch, Karen E; McCarty, Donald R; Davis, Mark F; Thomas, Steven R; McCann, Maureen C; Carpita, Nicholas C

2009-12-01

Grass species represent a major source of food, feed, and fiber crops and potential feedstocks for biofuel production. Most of the biomass is contributed by cell walls that are distinct in composition from all other flowering plants. Identifying cell wall-related genes and their functions underpins a fundamental understanding of growth and development in these species. Toward this goal, we are building a knowledge base of the maize (Zea mays) genes involved in cell wall biology, their expression profiles, and the phenotypic consequences of mutation. Over 750 maize genes were annotated and assembled into gene families predicted to function in cell wall biogenesis. Comparative genomics of maize, rice (Oryza sativa), and Arabidopsis (Arabidopsis thaliana) sequences reveal differences in gene family structure between grass species and a reference eudicot species. Analysis of transcript profile data for cell wall genes in developing maize ovaries revealed that expression within families differed by up to 100-fold. When transcriptional analyses of developing ovaries before pollination from Arabidopsis, rice, and maize were contrasted, distinct sets of cell wall genes were expressed in grasses. These differences in gene family structure and expression between Arabidopsis and the grasses underscore the requirement for a grass-specific genetic model for functional analyses. A UniformMu population proved to be an important resource in both forward- and reverse-genetics approaches to identify hundreds of mutants in cell wall genes. A forward screen of field-grown lines by near-infrared spectroscopic screen of mature leaves yielded several dozen lines with heritable spectroscopic phenotypes. Pyrolysis-molecular beam mass spectrometry confirmed that several nir mutants had altered carbohydrate-lignin compositions.

Reinforcement effect of soy protein/carbohydrate ratio in styrene-butadiene polymer

USDA-ARS?s Scientific Manuscript database

Soy protein and carbohydrate at different ratios were blended with latex to form composites. The variation of protein to carbohydrate ratio has a sifnificant effect on the composite properties and the results from dynamic mechanical method showed a substantial reinforcement effect. The composites ...

Chemical characterisation and analysis of the cell wall polysaccharides of duckweed (Lemna minor).

PubMed

Zhao, X; Moates, G K; Wellner, N; Collins, S R A; Coleman, M J; Waldron, K W

2014-10-13

Duckweed is potentially an ideal biofuel feedstock due to its high proportion of cellulose and starch and low lignin content. However, there is little detailed information on the composition and structure of duckweed cell walls relevant to optimising the conversion of duckweed biomass to ethanol and other biorefinery products. This study reports that, for the variety and batch evaluated, carbohydrates constitute 51.2% (w/w) of dry matter while starch accounts for 19.9%. This study, for the first time, analyses duckweed cell wall composition through a detailed sequential extraction. The cell wall is rich in cellulose and also contains 20.3% pectin comprising galacturonan, xylogalacturonan, rhamnogalacturonan; 3.5% hemicellulose comprising xyloglucan and xylan, and 0.03% phenolics. In addition, essential fatty acids (0.6%, α-linolenic and linoleic/linoelaidic acid) and p-coumaric acid (0.015%) respectively are the most abundant fatty acids and phenolics in whole duckweed. Copyright © 2014 Elsevier Ltd. All rights reserved.

Preparation of water-soluble glycoconjugated poly(acrylamide) for NMR analyses of carbohydrate-carbohydrate interactions

NASA Astrophysics Data System (ADS)

Xuan, Trinh Anh; Trung, Phan Nghia; Dinh, Bui Long; Yamaguchi, Takumi; Kato, Koichi

2014-05-01

Oligosaccharide chains of glycoconjugates are important biopolymers not only as carriers of information in cell-cell interactions but also as markers of cellular differentiation, aging, and malignant alteration. Molecular interactions where carbohydrates are involved are usually considered as weak interactions, so the study and evaluation of these interactions is still in its infancy. The evidences and studies of carbohydrate-carbohydrate interactions (CCI) will be confirming the importance of this mechanism for specific cell adhesion and communication. Their development will go hand in hand with the development of new and more sensitive techniques to study weak interactions. Recently, synthetic glycopolymers with functions similar to those of such natural carbohydrates and with specific pendant saccharide moieties were used as a solution for enhancement CCI when forming polyvalent interactions. Carbohydrates are ubiquitous components of cell wall membranes and occur as glycolipids, glycoproteins, proteoglycans, and capsular polysaccharides. As such they can participate in forefront intramolecular and intracellular events. Apart from their recognized roles in the physicochemical properties of glycolipids and glycoproteins. In this study, we designed trisaccharide monomers for free radical polymerization. Subsequently, the trisaccharide unit for chemical conjugation was synthesized from galactosamine in good yield. For further NMR analyses of CCI, glycopolymers composed of these sugar derivatives will be provided.

Modified carbohydrate-chitosan compounds, methods of making the same and methods of using the same

DOEpatents

Venditti, Richard A; Pawlak, Joel J; Salam, Abdus; El-Tahlawy, Khaled Fathy

2015-03-10

Compositions of matter are provided that include chitosan and a modified carbohydrate. The modified carbohydrate includes a carbohydrate component and a cross linking agent. The modified carbohydrate has increased carboxyl content as compared to an unmodified counterpart carbohydrate. A carboxyl group of the modified carbohydrate is covalently bonded with an amino group of chitosan. The compositions of matter provided herein may include cross linked starch citrate-chitosan and cross linked hemicellulose citrate-chitosan, including foams thereof. These compositions yield excellent absorbency and metal chelation properties. Methods of making cross linked modified carbohydrate-chitosan compounds are also provided.

Elastic torsional buckling of thin-walled composite cylinders

NASA Technical Reports Server (NTRS)

Marlowe, D. E.; Sushinsky, G. F.; Dexter, H. B.

1974-01-01

The elastic torsional buckling strength has been determined experimentally for thin-walled cylinders fabricated with glass/epoxy, boron/epoxy, and graphite/epoxy composite materials and composite-reinforced aluminum and titanium. Cylinders have been tested with several unidirectional-ply orientations and several cross-ply layups. Specimens were designed with diameter-to-thickness ratios of approximately 150 and 300 and in two lengths of 10 in. and 20 in. The results of these tests were compared with the buckling strengths predicted by the torsional buckling analysis of Chao.

Effects of carbohydrate quantity and glycemic index on resting metabolic rate and body composition during weight loss

USDA-ARS?s Scientific Manuscript database

Objective: To examine the effects of diets varying in carbohydrate and glycemic index (GI) on changes in body composition, resting metabolic rate (RMR), and metabolic adaptation during and after weight loss. Methods: Adults with obesity (n = 91) were randomized to one of four provided-food diets f...

Amino Acid Composition of Protein-Enriched Dried Pasta:
Is It Suitable for a Low-Carbohydrate Diet?

PubMed

Filip, Sebastjan; Vidrih, Rajko

2015-09-01

Today, obesity is one of the major health problems, a so-called epidemic of the developed world. Obesity arises through an imbalance between energy intake and energy expenditure, so it is important for products to have a balanced nutritional composition. The aim of this study is to prepare high-protein pasta with high nutritional quality, with emphasis on its amino acid composition, as ordinary durum pasta lacks lysine and threonine. Ordinary durum wheat pasta contains, on average, 77% carbohydrate, and can have even less than 10% protein. It is therefore often excluded from normal energy-restricted diets, and especially from low-carbohydrate diets. In this study pasta that can satisfy the nutritional requirements of a low-carbohydrate diet and is suitable for daily use was developed and evaluated. Protein-enhanced pasta was produced by adding high amounts of plant protein extract (40% dry matter) without (plain high-protein pasta) or with 3% dried spinach powder (high-protein spinach pasta) to durum wheat semolina. According to the sensory analysis data, the addition of 40% of plant protein extract satisfied sensory and nutritional requirements, allowing further development and evaluation for possible marketing. This analysis shows that these high-protein neutral and spinach pasta contain 36.4 and 39.6 g of protein per 100 g of dry mass, 12.07 and 14.70 g of total essential amino acids per 100 g of dry mass, and a high content of branched-chain amino acids, i.e. 5.54 and 6.65 g per 100 g of dry mass, respectively. This therefore represents a true alternative to durum wheat pasta for low-carbohydrate diets.

Amino Acid Composition of Protein-Enriched Dried Pasta:
Is It Suitable for a Low-Carbohydrate Diet?

PubMed Central

Vidrih, Rajko

2015-01-01

Summary Today, obesity is one of the major health problems, a so-called epidemic of the developed world. Obesity arises through an imbalance between energy intake and energy expenditure, so it is important for products to have a balanced nutritional composition. The aim of this study is to prepare high-protein pasta with high nutritional quality, with emphasis on its amino acid composition, as ordinary durum pasta lacks lysine and threonine. Ordinary durum wheat pasta contains, on average, 77% carbohydrate, and can have even less than 10% protein. It is therefore often excluded from normal energy-restricted diets, and especially from low-carbohydrate diets. In this study pasta that can satisfy the nutritional requirements of a low-carbohydrate diet and is suitable for daily use was developed and evaluated. Protein-enhanced pasta was produced by adding high amounts of plant protein extract (40% dry matter) without (plain high-protein pasta) or with 3% dried spinach powder (high-protein spinach pasta) to durum wheat semolina. According to the sensory analysis data, the addition of 40% of plant protein extract satisfied sensory and nutritional requirements, allowing further development and evaluation for possible marketing. This analysis shows that these high-protein neutral and spinach pasta contain 36.4 and 39.6 g of protein per 100 g of dry mass, 12.07 and 14.70 g of total essential amino acids per 100 g of dry mass, and a high content of branched-chain amino acids, i.e. 5.54 and 6.65 g per 100 g of dry mass, respectively. This therefore represents a true alternative to durum wheat pasta for low-carbohydrate diets. PMID:27904361

Liver Fatty Acid Composition and Inflammation in Mice Fed with High-Carbohydrate Diet or High-Fat Diet.

PubMed

da Silva-Santi, Lorena Gimenez; Antunes, Marina Masetto; Caparroz-Assef, Silvana Martins; Carbonera, Fabiana; Masi, Laureane Nunes; Curi, Rui; Visentainer, Jesuí Vergílio; Bazotte, Roberto Barbosa

2016-10-29

Both high-carbohydrate diet (HCD) and high-fat diet (HFD) modulate liver fat accumulation and inflammation, however, there is a lack of data on the potential contribution of carbohydrates and lipids separately. For this reason, the changes in liver fatty acid (FA) composition in male Swiss mice fed with HCD or HFD were compared, at the time points 0 (before starting the diets), and after 7, 14, 28 or 56 days. Activities of stearoyl-CoA desaturase-1 (SCD-1), ∆-6 desaturase (D6D), elongases and de novo lipogenesis (DNL) were estimated. Liver mRNA expression of acetyl-CoA carboxylase 1 (ACC1) was evaluated as an additional indicator of the de novo lipogenesis. Myeloperoxidase activity, nitric oxide (NO) production, and mRNA expressions of F4/80, type I collagen, interleukin (IL)-6, IL-1β, IL-10, and tumor necrosis factor-α (TNF-α) were measured as indication of the liver inflammatory state. The HCD group had more intense lipid deposition, particularly of saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs). This group also showed higher DNL, SCD-1, and D6D activities associated with increased NO concentration, as well as myeloperoxidase activity. Livers from the HFD group showed higher elongase activity, stored more polyunsaturated fatty acids (PUFAs) and had a lower omega-6/omega-3 fatty acid ( n -6/ n -3) ratio. In conclusion, liver lipid accumulation, fatty acids (FA) composition and inflammation were modulated by the dietary composition of lipids and carbohydrates. The HCD group had more potent lipogenic and inflammatory effects in comparison with HFD.

Structural Studies of Complex Carbohydrates of Plant Cell Walls

DOE Office of Scientific and Technical Information (OSTI.GOV)

Darvill, Alan; Hahn, Michael G.; O'Neill, Malcolm A.

Most of the solar energy captured by land plants is converted into the polysaccharides (cellulose, hemicellulose, and pectin) that are the predominant components of the cell wall. These walls, which account for the bulk of plant biomass, have numerous roles in the growth and development of plants. Moreover, these walls have a major impact on human life as they are a renewable source of biomass, a source of diverse commercially useful polymers, a major component of wood, and a source of nutrition for humans and livestock. Thus, understanding the molecular mechanisms that lead to wall assembly and how cell wallsmore » and their component polysaccharides contribute to plant growth and development is essential to improve and extend the productivity and value of plant materials. The proposed research will develop and apply advanced analytical and immunological techniques to study specific changes in the structures and interactions of the hemicellulosic and pectic polysaccharides that occur during differentiation and in response to genetic modification and chemical treatments that affect wall biosynthesis. These new techniques will make it possible to accurately characterize minute amounts of cell wall polysaccharides so that subtle changes in structure that occur in individual cell types can be identified and correlated to the physiological or developmental state of the plant. Successful implementation of this research will reveal fundamental relationships between polysaccharide structure, cell wall architecture, and cell wall functions.« less

Recognition of Histo-Blood Group Antigen-Like Carbohydrates in Lettuce by Human GII.4 Norovirus

PubMed Central

Gao, Xiang; Esseili, Malak A.; Lu, Zhongyan; Saif, Linda J.

2016-01-01

ABSTRACT Human norovirus (HuNoV) genogroup II genotype 4 (GII.4) strains account for about 80% of the gastroenteritis outbreaks in the United States. Contaminated food is a major transmission vehicle for this virus. In humans, pigs, and oysters, histo-blood group antigens (HBGAs) act as attachment factors for HuNoVs. In lettuce, although the virus-like particles (VLPs) of a GII.4 HuNoV were found to bind to cell wall carbohydrates, the exact binding site has not been investigated. Here, we show the presence of HBGA-like carbohydrates in the cell wall of lettuce. The digestion of lettuce leaves with cell wall-degrading enzymes exposed more binding sites and significantly increased the level of binding of GII.4 HuNoV VLPs. Competition assays showed that both the HBGA monoclonal antibody, recognizing the H type, and plant lectins, recognizing α-l-fucose in the H type, effectively inhibited VLP binding to lettuce tissues. Lettuce cell wall components were isolated and their NoV VLP binding characteristics were tested by enzyme-linked immunosorbent assays. The binding was inhibited by pretreatment of the lettuce cell wall materials with α-1,2-fucosidase. Collectively, our results indicate that H-type HBGA-like carbohydrates exist in lettuce tissues and that GII.4 HuNoV VLPs can bind the exposed fucose moiety, possibly in the hemicellulose component of the cell wall. IMPORTANCE Salad crops and fruits are increasingly recognized as vehicles for human norovirus (HuNoV) transmission. A recent study showed that HuNoVs specifically bind to the carbohydrates of the lettuce cell wall. Histo-blood group antigens (HBGAs) are carbohydrates and are known as the attachment factors for HuNoV infection in humans. In this study, we show the presence of HBGA-like carbohydrates in lettuce, to which HuNoVs specifically bind. These results suggest that specifically bound HuNoVs cannot be removed by simple washing, which may allow viral transmission to consumers. Our findings provide new

Recognition of Histo-Blood Group Antigen-Like Carbohydrates in Lettuce by Human GII.4 Norovirus.

PubMed

Gao, Xiang; Esseili, Malak A; Lu, Zhongyan; Saif, Linda J; Wang, Qiuhong

2016-05-15

Human norovirus (HuNoV) genogroup II genotype 4 (GII.4) strains account for about 80% of the gastroenteritis outbreaks in the United States. Contaminated food is a major transmission vehicle for this virus. In humans, pigs, and oysters, histo-blood group antigens (HBGAs) act as attachment factors for HuNoVs. In lettuce, although the virus-like particles (VLPs) of a GII.4 HuNoV were found to bind to cell wall carbohydrates, the exact binding site has not been investigated. Here, we show the presence of HBGA-like carbohydrates in the cell wall of lettuce. The digestion of lettuce leaves with cell wall-degrading enzymes exposed more binding sites and significantly increased the level of binding of GII.4 HuNoV VLPs. Competition assays showed that both the HBGA monoclonal antibody, recognizing the H type, and plant lectins, recognizing α-l-fucose in the H type, effectively inhibited VLP binding to lettuce tissues. Lettuce cell wall components were isolated and their NoV VLP binding characteristics were tested by enzyme-linked immunosorbent assays. The binding was inhibited by pretreatment of the lettuce cell wall materials with α-1,2-fucosidase. Collectively, our results indicate that H-type HBGA-like carbohydrates exist in lettuce tissues and that GII.4 HuNoV VLPs can bind the exposed fucose moiety, possibly in the hemicellulose component of the cell wall. Salad crops and fruits are increasingly recognized as vehicles for human norovirus (HuNoV) transmission. A recent study showed that HuNoVs specifically bind to the carbohydrates of the lettuce cell wall. Histo-blood group antigens (HBGAs) are carbohydrates and are known as the attachment factors for HuNoV infection in humans. In this study, we show the presence of HBGA-like carbohydrates in lettuce, to which HuNoVs specifically bind. These results suggest that specifically bound HuNoVs cannot be removed by simple washing, which may allow viral transmission to consumers. Our findings provide new information needed

The composition of cell walls from grape skin in Vitis vinifera intraspecific hybrids.

PubMed

Apolinar-Valiente, Rafael; Gómez-Plaza, Encarna; Terrier, Nancy; Doco, Thierry; Ros-García, José María

2017-09-01

Monastrell is a red grape cultivar adapted to the dry environmental conditions of Murcia, SE Spain. Its berries seem to be characterized by a rigid cell wall structure, which could make difficult the winemaking process. Cabernet Sauvignon cultivar is used to complement Monastrell wines in this region owing to its high phenolic content with high extractability. This study explores the skin cell wall composition of grapes from plants resulting from intraspecific crosses of Vitis vinifera cultivars Monastrell × Cabernet Sauvignon. Moreover, the morphology of the cell wall material (CWM) from some representative samples was visualized by transmission optical microscopy. The total sugar content of CWM from nine out of ten genotypes of the progeny was lower than that from Monastrell. Seven out of ten genotypes showed lower phenolic content than Cabernet Sauvignon. The CWM from nine out of ten hybrids presented lower protein content than that from Monastrell. This study confirms that skin cell walls from Monastrell × Cabernet Sauvignon hybrid grapes presented major differences in composition compared with their parents. These data could help in the development of new cultivars adapted to the dry conditions of SE Spain and with a cell wall composition favouring extractability. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Size-fractionated dissolved primary production and carbohydrate composition of the coccolithophore Emiliania huxleyi

NASA Astrophysics Data System (ADS)

Borchard, C.; Engel, A.

2015-02-01

Extracellular release (ER) by phytoplankton is the major source of fresh dissolved organic carbon (DOC) in marine ecosystems and accompanies primary production during all growth phases. Little is known, so far, on size and composition of released molecules, and to which extent ER occurs passively, by leakage, or actively, by exudation. Here, we report on ER by the widespread and bloom-forming coccolithophore Emiliania huxleyi grown under steady-state conditions in phosphorus-controlled chemostats (N:P = 29, growth rate of μ = 0.2 d-1) at present-day and high-CO2 concentrations. 14C incubations were performed to determine primary production (PP), comprised of particulate (PO14C) and dissolved organic carbon (DO14C). Concentration and composition of particulate combined carbohydrates (pCCHO) and high-molecular-weight (>1 kDa, HMW) dissolved combined carbohydrates (dCCHO) were determined by ion chromatography. Information on size distribution of ER products was obtained by investigating distinct size classes (<0.4 μm (DO14C), <0.45 μm (HMW-dCCHO), <1000, <100 and <10 kDa) of DO14CC and HMW-dCCHO. Our results revealed relatively low ER during steady-state growth, corresponding to ~4.5% of primary production, and similar ER rates for all size classes. Acidic sugars had a significant share on freshly produced pCCHO as well as on HMW-dCCHO. While pCCHO and the smallest size fraction (<10 kDa) of HMW-dCCHO exhibited a similar sugar composition, dominated by high percentage of glucose (74-80 mol%), the composition of HMW-dCCHO size classes >10 kDa was significantly different, with a higher mol% of arabinose. The mol% of acidic sugars increased and that of glucose decreased with increasing size of HMW-dCCHO. We conclude that larger polysaccharides follow different production and release pathways than smaller molecules, potentially serving distinct ecological and biogeochemical functions.

Evaluation of a new composite prosthesis for the repair of abdominal wall defects.

PubMed

Losi, Paola; Munaò, Antonella; Spiller, Dario; Briganti, Enrica; Martinelli, Ilaria; Scoccianti, Marco; Soldani, Giorgio

2007-10-01

The degree of integration of biomaterials used in the repair of abdominal wall defects seems to depend upon the structure of the prosthesis. The present investigation evaluates the behaviour in terms of adhesion formation and integration of a new composite prosthesis that could be employed in this clinical application. Full-thickness abdominal wall defects (7 x 5 cm) were created in 16 anaesthetized New Zealand white rabbits and the prosthesis were placed in direct contact with the visceral peritoneum during the experiment. The defects were repaired with a composite prosthesis or pure polypropylene mesh to establish two study groups (n = 8 each). The composite device was constituted by a polypropylene mesh physically attached to a poly(ether)urethane-polydimethylsiloxane laminar sheet. Animals were sacrificed 7, 14, 21 and 30 days after implant and prosthesis/surrounding tissue specimens subjected to light and electron microscopy. Firm adhesions were detected in the polypropylene implants, while they were not present in the composite implants. The excellent behaviour of the composite prosthesis shown in this study warrants further investigation on its use for the repair of abdominal wall defects when a prosthetic device needs to be placed in contact with the intestinal loops.

Electro-Responsive Behaviour Multi-Wall Nanotubes/Gelatin Composites and Cross-Linked Gelatin Electrospun Mats

DTIC Science & Technology

2008-02-11

sample , could explain large swelling in blend samples which might enhance ions diffusion and lead to an increase of bending. 21 References [1...1 Final Report on Electro-responsive behaviour multi-wall nanotubes/gelatin composites and cross-linked gelatin electrospun mats...12-10-2007 4. TITLE AND SUBTITLE Electro-responsive behaviour multi-wall nanotubes/gelatin composites and cross-linked gelatin electrospun mats

The effect of grain size and surface area on organic matter, lignin and carbohydrate concentration, and molecular compositions in Peru Margin sediments

NASA Astrophysics Data System (ADS)

Bergamaschi, Brian A.; Tsamakis, Elizabeth; Keil, Richard G.; Eglinton, Timothy I.; Montluçon, Daniel B.; Hedges, John I.

1997-03-01

A C-rich sediment sample from the Peru Margin was sorted into nine hydrodynamically-determined grain size fractions to explore the effect of grain size distribution and sediment surface area on organic matter content and composition. The neutral monomeric carbohydrate composition, lignin oxidation product yields, total organic carbon, and total nitrogen contents were determined independently for each size fraction, in addition to sediment surface area and abundance of biogenic opal. The percent organic carbon and percent total nitrogen were strongly related to surface area in these sediments. In turn, the distribution of surface area closely followed mass distribution among the textural size classes, suggesting hydrodynamic controls on grain size also control organic carbon content. Nevertheless, organic compositional distinctions were observed between textural size classes. Total neutral carbohydrate yields in the Peru Margin sediments were found to closely parallel trends in total organic carbon, increasing in abundance among grain size fractions in proportion to sediment surface area. Coincident with the increases in absolute abundance, rhamnose and mannose increased as a fraction of the total carbohydrate yield in concert with surface area, indicating these monomers were preferentially represented in carbohydrates associated with surfaces. Lignin oxidation product yields varied with surface area when normalized to organic carbon, suggesting that the terrestrially-derived component may be diluted by sorption of marine derived material. Lignin-based parameters suggest a separate source for terrestrially derived material associated with sand-size material as opposed to that associated with silts and clays.

Structural differences between the lignin-carbohydrate complexes present in wood and in chemical pulps.

PubMed

Lawoko, Martin; Henriksson, Gunnar; Gellerstedt, Göran

2005-01-01

Lignin-carbohydrate complexes (LCCs) were prepared in quantitative yield from spruce wood and from the corresponding kraft and oxygen-delignified pulps and were separated into different fractions on the basis of their carbohydrate composition. To obtain an understanding of the differences in lignin structure and reactivity within the various LCC fractions, thioacidolysis in combination with gas chromatography was used to quantify the content of beta-O-4 structures in the lignin. Periodate oxidation followed by determination of methanol was used to quantify the phenolic hydroxyl groups. Furthermore, size exclusion chromatography (SEC) of the thioacidolysis fractions was used to monitor any differences between the original molecular size distribution and that after the delignification processes. Characteristic differences between the various LCC fractions were observed, clearly indicating that two different forms of lignin are present in the wood fiber wall. These forms are linked to glucomannan and xylan, respectively. On pulping, the different LCCs have different reactivities. The xylan-linked lignin is to a large extent degraded, whereas the glucomannan-linked lignin undergoes a partial condensation to form more high molecular mass material. The latter seems to be rather unchanged during a subsequent oxygen-delignification stage. On the basis of these findings, a modified arrangement of the fiber wall polymers is suggested.

Study on Shear Performance of Cold-formed Steel Composite Wall with New Type of stud

NASA Astrophysics Data System (ADS)

Wang, Chungang; Yue, Sizhe; Liu, Hong; Zhang, Zhuangnan

2018-03-01

The shear resistance of single oriented-strand board wall and single gypsum board wall can be improved in different degrees by increasing strength of steel. The experimental data of literatures were used, and the test specimens had been simulated and validated by ABAQUS finite element analysis. According to the research, it showed that the compressive bearing capacity of the new stud composite wall was much better than the common stud composite wall, so the establishment and research of all models had been based on the new section stud. The analysis results show that when using new type of stud the shear resistance of the single oriented-strand board wall can be improved efficiently by increasing strength of steel, but the shear resistance of the single gypsum wall can be increased little.

Stomatal cell wall composition: distinctive structural patterns associated with different phylogenetic groups

PubMed Central

Shtein, Ilana; Shelef, Yaniv; Marom, Ziv; Zelinger, Einat; Schwartz, Amnon; Popper, Zoë A.; Bar-On, Benny

2017-01-01

Background and Aims Stomatal morphology and function have remained largely conserved throughout ∼400 million years of plant evolution. However, plant cell wall composition has evolved and changed. Here stomatal cell wall composition was investigated in different vascular plant groups in attempt to understand their possible effect on stomatal function. Methods A renewed look at stomatal cell walls was attempted utilizing digitalized polar microscopy, confocal microscopy, histology and a numerical finite-elements simulation. The six species of vascular plants chosen for this study cover a broad structural, ecophysiological and evolutionary spectrum: ferns (Asplenium nidus and Platycerium bifurcatum) and angiosperms (Arabidopsis thaliana and Commelina erecta) with kidney-shaped stomata, and grasses (angiosperms, family Poaceae) with dumbbell-shaped stomata (Sorghum bicolor and Triticum aestivum). Key Results Three distinct patterns of cellulose crystallinity in stomatal cell walls were observed: Type I (kidney-shaped stomata, ferns), Type II (kidney-shaped stomata, angiosperms) and Type III (dumbbell-shaped stomata, grasses). The different stomatal cell wall attributes investigated (cellulose crystallinity, pectins, lignin, phenolics) exhibited taxon-specific patterns, with reciprocal substitution of structural elements in the end-walls of kidney-shaped stomata. According to a numerical bio-mechanical model, the end walls of kidney-shaped stomata develop the highest stresses during opening. Conclusions The data presented demonstrate for the first time the existence of distinct spatial patterns of varying cellulose crystallinity in guard cell walls. It is also highly intriguing that in angiosperms crystalline cellulose appears to have replaced lignin that occurs in the stomatal end-walls of ferns serving a similar wall strengthening function. Such taxon-specific spatial patterns of cell wall components could imply different biomechanical functions, which in turn

Stomatal cell wall composition: distinctive structural patterns associated with different phylogenetic groups.

PubMed

Shtein, Ilana; Shelef, Yaniv; Marom, Ziv; Zelinger, Einat; Schwartz, Amnon; Popper, Zoë A; Bar-On, Benny; Harpaz-Saad, Smadar

2017-04-01

Stomatal morphology and function have remained largely conserved throughout ∼400 million years of plant evolution. However, plant cell wall composition has evolved and changed. Here stomatal cell wall composition was investigated in different vascular plant groups in attempt to understand their possible effect on stomatal function. A renewed look at stomatal cell walls was attempted utilizing digitalized polar microscopy, confocal microscopy, histology and a numerical finite-elements simulation. The six species of vascular plants chosen for this study cover a broad structural, ecophysiological and evolutionary spectrum: ferns ( Asplenium nidus and Platycerium bifurcatum ) and angiosperms ( Arabidopsis thaliana and Commelina erecta ) with kidney-shaped stomata, and grasses (angiosperms, family Poaceae) with dumbbell-shaped stomata ( Sorghum bicolor and Triticum aestivum ). Three distinct patterns of cellulose crystallinity in stomatal cell walls were observed: Type I (kidney-shaped stomata, ferns), Type II (kidney-shaped stomata, angiosperms) and Type III (dumbbell-shaped stomata, grasses). The different stomatal cell wall attributes investigated (cellulose crystallinity, pectins, lignin, phenolics) exhibited taxon-specific patterns, with reciprocal substitution of structural elements in the end-walls of kidney-shaped stomata. According to a numerical bio-mechanical model, the end walls of kidney-shaped stomata develop the highest stresses during opening. The data presented demonstrate for the first time the existence of distinct spatial patterns of varying cellulose crystallinity in guard cell walls. It is also highly intriguing that in angiosperms crystalline cellulose appears to have replaced lignin that occurs in the stomatal end-walls of ferns serving a similar wall strengthening function. Such taxon-specific spatial patterns of cell wall components could imply different biomechanical functions, which in turn could be a consequence of differences in

Performance and quality-control standards for composite floor, wall, and truss framing

Treesearch

Gerald A. Koenigshof

1985-01-01

Users must be assured that composite structural members are satisfactory for their intended purposes. Standards are provided for strength, stiffness, durability, and dimensional stability of composite floor, wall, and truss-framing members. Methods for enforcing compliance with the standards are suggested.

Carbohydrate absorption from one serving of fruit juice in young children: age and carbohydrate composition effects.

PubMed

Nobigrot, T; Chasalow, F I; Lifshitz, F

1997-04-01

To test the hypotheses that: the efficiency of carbohydrate absorption in childhood increases with age, and decreased carbohydrate absorption occurs more frequently with juices containing more fructose than glucose and/or sorbitol than with juices which contain equal amounts of fructose and glucose and are sorbitol-free. One hundred and four healthy children were recruited from the Ambulatory Center at Maimonides Children's Center. They were assigned to one of three age groups: approximately 1, 3 and 5 years of age. Each child received one age-specific dose (by randomization) of one of four juices: a) pear juice which contains fructose in excess to glucose and a large amount of sorbitol; b) apple juice which is similar to pear juice in its fructose to glucose ratio but contains four times less sorbitol than pear juice; c) white grape juice or d) purple grape juice both of which contain equal amounts of fructose and glucose and are sorbitol-free. Breath hydrogen excretion (BH2) was utilized as the index of carbohydrate absorption. It was measured in fasting children and at 30-minute intervals for 3 hours after drinking the single serving of juice. Multiple breath hydrogen related parameters were quantified and results were expressed as: BH2 peak, area under the curve, and degree of carbohydrate malabsorption. After the test, parents completed a questionnaire and recorded signs and symptoms of intestinal malabsorption for 24 hours. Pear juice related BH2 levels were significantly higher among children 1 and 3 years of age as compared to the levels achieved after the other juices. Apple juice related BH2 levels were significantly higher only among the youngest age group of children. There was no significant difference in carbohydrate absorption among the 5 year old children regardless of the juice consumed. Incomplete carbohydrate absorption (BH2 peak above 20 ppm) occurred more frequently after pear juice consumption (84%) than after apple juice (41%) or grape juice

Dynamic changes in transcriptome and cell wall composition underlying brassinosteroid-mediated lignification of switchgrass suspension cells.

PubMed

Rao, Xiaolan; Shen, Hui; Pattathil, Sivakumar; Hahn, Michael G; Gelineo-Albersheim, Ivana; Mohnen, Debra; Pu, Yunqiao; Ragauskas, Arthur J; Chen, Xin; Chen, Fang; Dixon, Richard A

2017-01-01

Plant cell walls contribute the majority of plant biomass that can be used to produce transportation fuels. However, the complexity and variability in composition and structure of cell walls, particularly the presence of lignin, negatively impacts their deconstruction for bioenergy. Metabolic and genetic changes associated with secondary wall development in the biofuel crop switchgrass ( Panicum virgatum ) have yet to be reported. Our previous studies have established a cell suspension system for switchgrass, in which cell wall lignification can be induced by application of brassinolide (BL). We have now collected cell wall composition and microarray-based transcriptome profiles for BL-induced and non-induced suspension cultures to provide an overview of the dynamic changes in transcriptional reprogramming during BL-induced cell wall modification. From this analysis, we have identified changes in candidate genes involved in cell wall precursor synthesis, cellulose, hemicellulose, and pectin formation and ester-linkage generation. We have also identified a large number of transcription factors with expression correlated with lignin biosynthesis genes, among which are candidates for control of syringyl (S) lignin accumulation. Together, this work provides an overview of the dynamic compositional changes during brassinosteroid-induced cell wall remodeling, and identifies candidate genes for future plant genetic engineering to overcome cell wall recalcitrance.

Bioinspired assemblies of plant cell wall polymers unravel the affinity properties of carbohydrate-binding modules.

PubMed

Paës, Gabriel; von Schantz, Laura; Ohlin, Mats

2015-09-07

Lignocellulose-acting enzymes play a central role in the biorefinery of plant biomass to make fuels, chemicals and materials. These enzymes are often appended to carbohydrate binding modules (CBMs) that promote substrate targeting. When used in plant materials, which are complex assemblies of polymers, the binding properties of CBMs can be difficult to understand and predict, thus limiting the efficiency of enzymes. In order to gain more information on the binding properties of CBMs, some bioinspired model assemblies that contain some of the polymers and covalent interactions found in the plant cell walls have been designed. The mobility of three engineered CBMs has been investigated by FRAP in these assemblies, while varying the parameters related to the polymer concentration, the physical state of assemblies and the oligomerization state of CBMs. The features controlling the mobility of the CBMs in the assemblies have been quantified and hierarchized. We demonstrate that the parameters can have additional or opposite effects on mobility, depending on the CBM tested. We also find evidence of a relationship between the mobility of CBMs and their binding strength. Overall, bioinspired assemblies are able to reveal the unique features of affinity of CBMs. In particular, the results show that oligomerization of CBMs and the presence of ferulic acid motifs in the assemblies play an important role in the binding affinity of CBMs. Thus we propose that these features should be finely tuned when CBMs are used in plant cell walls to optimise bioprocesses.

Composite asymptotic expansions and scaling wall turbulence.

PubMed

Panton, Ronald L

2007-03-15

In this article, the assumptions and reasoning that yield composite asymptotic expansions for wall turbulence are discussed. Particular attention is paid to the scaling quantities that are used to render the variables non-dimensional and of order one. An asymptotic expansion is proposed for the streamwise Reynolds stress that accounts for the active and inactive turbulence by using different scalings. The idea is tested with the data from the channel flows and appears to have merit.

Imaging Cell Wall Architecture in Single Zinnia elegans Tracheary Elements1[OA

PubMed Central

Lacayo, Catherine I.; Malkin, Alexander J.; Holman, Hoi-Ying N.; Chen, Liang; Ding, Shi-You; Hwang, Mona S.; Thelen, Michael P.

2010-01-01

The chemical and structural organization of the plant cell wall was examined in Zinnia elegans tracheary elements (TEs), which specialize by developing prominent secondary wall thickenings underlying the primary wall during xylogenesis in vitro. Three imaging platforms were used in conjunction with chemical extraction of wall components to investigate the composition and structure of single Zinnia TEs. Using fluorescence microscopy with a green fluorescent protein-tagged Clostridium thermocellum family 3 carbohydrate-binding module specific for crystalline cellulose, we found that cellulose accessibility and binding in TEs increased significantly following an acidified chlorite treatment. Examination of chemical composition by synchrotron radiation-based Fourier-transform infrared spectromicroscopy indicated a loss of lignin and a modest loss of other polysaccharides in treated TEs. Atomic force microscopy was used to extensively characterize the topography of cell wall surfaces in TEs, revealing an outer granular matrix covering the underlying meshwork of cellulose fibrils. The internal organization of TEs was determined using secondary wall fragments generated by sonication. Atomic force microscopy revealed that the resulting rings, spirals, and reticulate structures were composed of fibrils arranged in parallel. Based on these combined results, we generated an architectural model of Zinnia TEs composed of three layers: an outermost granular layer, a middle primary wall composed of a meshwork of cellulose fibrils, and inner secondary wall thickenings containing parallel cellulose fibrils. In addition to insights in plant biology, studies using Zinnia TEs could prove especially productive in assessing cell wall responses to enzymatic and microbial degradation, thus aiding current efforts in lignocellulosic biofuel production. PMID:20592039

Mechanisms involved in the regulation of photosynthetic efficiency and carbohydrate partitioning in response to low- and high-temperature flooding triggered in winter rye (Secale cereale) lines with distinct pink snow mold resistances.

PubMed

Pociecha, E; Rapacz, M; Dziurka, M; Kolasińska, I

2016-07-01

In terms of climate changes and global warming, winter hardiness could be determined by unfavorable environmental conditions other than frost. These could include flooding from melting snow and/or rain, coincident with fungal diseases. Therefore, we designed an experiment to identify potential common mechanisms of flooding tolerance and snow mold resistance, involving the regulation of photosynthetic efficiency and carbohydrate metabolism at low temperatures. Snow mold-resistant and susceptible winter rye (Secale cereale) plants were characterized by considerably different patterns of response to flooding. These differences were clearer at low temperature, thus confirming a possible role of the observed changes in snow mold tolerance. The resistant plants were characterized by lower PSII quantum yields at low temperature, combined with much higher energy flux for energy dissipation from the PSII reaction center. During flooding, the level of soluble carbohydrates increased in the resistant plants and decreased in the susceptible ones. Thus increase in resistant line was connected with a decrease in the energy dissipation rate in PSII/increased photosynthetic activity (energy flux for electron transport), a lower rate of starch degradation and higher rates of sucrose metabolism in leaves. The resistant lines accumulated larger amounts of total soluble carbohydrates in the crowns than in the leaves. Irrespective of flooding treatment, the resistant lines allocated more sugars for cell wall composition, both in the leaves and crowns. Our results clearly indicated that studies on carbohydrate changes at low temperatures or during anoxia should investigate not only the alterations in water-soluble and storage carbohydrates, but also cell wall carbohydrates. The patterns of changes observed after low and high-temperature flooding were different, indicating separate control mechanisms of these responses. These included changes in the photosynthetic apparatus, starch

The effect of grain size and surface area on organic matter, lignin and carbohydrate concentration, and molecular compositions in Peru Margin sediments

USGS Publications Warehouse

Bergamaschi, B.A.; Tsamakis, E.; Keil, R.G.; Eglinton, T.I.; Montlucon, D.B.; Hedges, J.I.

1997-01-01

A C-rich sediment sample from the Peru Margin was sorted into nine hydrodynamically-determined grain size fractions to explore the effect of grain size distribution and sediment surface area on organic matter content and composition. The neutral monomeric carbohydrate composition, lignin oxidation product yields, total organic carbon, and total nitrogen contents were determined independently for each size fraction, in addition to sediment surface area and abundance of biogenic opal. The percent organic carbon and percent total nitrogen were strongly related to surface area in these sediments. In turn, the distribution of surface area closely followed mass distribution among the textural size classes, suggesting hydrodynamic controls on grain size also control organic carbon content. Nevertheless, organic compositional distinctions were observed between textural size classes. Total neutral carbohydrate yields in the Peru Margin sediments were found to closely parallel trends in total organic carbon, increasing in abundance among grain size fractions in proportion to sediment surface area. Coincident with the increases in absolute abundance, rhamnose and mannose increased as a fraction of the total carbohydrate yield in concert with surface area, indicating these monomers were preferentially represented in carbohydrates associated with surfaces. Lignin oxidation product yields varied with surface area when normalized to organic carbon, suggesting that the terrestrially-derived component may be diluted by sorption of marine derived material. Lignin-based parameters suggest a separate source for terrestrially derived material associated with sand-size material as opposed to that associated with silts and clays. Copyright ?? 1997 Elsevier Science Ltd.

Nonlinear analysis of composite thin-walled helicopter blades

NASA Astrophysics Data System (ADS)

Kalfon, J. P.; Rand, O.

Nonlinear theoretical modeling of laminated thin-walled composite helicopter rotor blades is presented. The derivation is based on nonlinear geometry with a detailed treatment of the body loads in the axial direction which are induced by the rotation. While the in-plane warping is neglected, a three-dimensional generic out-of-plane warping distribution is included. The formulation may also handle varying thicknesses and mass distribution along the cross-sectional walls. The problem is solved by successive iterations in which a system of equations is constructed and solved for each cross-section. In this method, the differential equations in the spanwise directions are formulated and solved using a finite-differences scheme which allows simple adaptation of the spanwise discretization mesh during iterations.

Cell Wall Composition and Candidate Biosynthesis Gene Expression During Rice Development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Fan; Manisseri, Chithra; Fagerström, Alexandra

Cell walls of grasses, including cereal crops and biofuel grasses, comprise the majority of plant biomass and intimately influence plant growth, development and physiology. However, the functions of many cell wall synthesis genes, and the relationships among and the functions of cell wall components remain obscure. To better understand the patterns of cell wall accumulation and identify genes that act in grass cell wall biosynthesis, we characterized 30 samples from aerial organs of rice (Oryza sativa cv. Kitaake) at 10 developmental time points, 3-100 d post-germination. Within these samples, we measured 15 cell wall chemical components, enzymatic digestibility and 18more » cell wall polysaccharide epitopes/ligands. We also used quantitative reverse transcription-PCR to measure expression of 50 glycosyltransferases, 15 acyltransferases and eight phenylpropanoid genes, many of which had previously been identified as being highly expressed in rice. Most cell wall components vary significantly during development, and correlations among them support current understanding of cell walls. We identified 92 significant correlations between cell wall components and gene expression and establish nine strong hypotheses for genes that synthesize xylans, mixed linkage glucan and pectin components. This work provides an extensive analysis of cell wall composition throughout rice development, identifies genes likely to synthesize grass cell walls, and provides a framework for development of genetically improved grasses for use in lignocellulosic biofuel production and agriculture.« less

Immuno and Affinity Cytochemical Analysis of Cell Wall Composition in the Moss Physcomitrella patens

DOE PAGES

Berry, Elizabeth A.; Tran, Mai L.; Dimos, Christos S.; ...

2016-03-08

In contrast to homeohydric vascular plants, mosses employ a poikilohydric strategy for surviving in the dry aerial environment. A detailed understanding of the structure, composition, and development of moss cell walls can contribute to our understanding of not only the evolution of overall cell wall complexity, but also the differences that have evolved in response to selection for different survival strategies. The model moss species Physcomitrella patens has a predominantly haploid lifecycle consisting of protonemal filaments that regenerate from protoplasts and enlarge by tip growth, and leafy gametophores composed of cells that enlarge by diffuse growth and differentiate into severalmore » different types. Advantages for genetic studies include methods for efficient targeted gene modification and extensive genomic resources. Immuno and affinity cytochemical labeling were used to examine the distribution of polysaccharides and proteins in regenerated protoplasts, protonemal filaments, rhizoids, and sectioned gametophores of P. patens. The cell wall composition of regenerated protoplasts was also characterized by flow cytometry. Crystalline cellulose was abundant in the cell walls of regenerating protoplasts and protonemal cells that developed on media of high osmolarity, whereas homogalactuonan was detected in the walls of protonemal cells that developed on low osmolarity media and not in regenerating protoplasts. Mannan was the major hemicellulose detected in all tissues tested. Arabinogalactan proteins were detected in different cell types by different probes, consistent with structural heterogneity. The results reveal developmental and cell type specific differences in cell wall composition and provide a basis for analyzing cell wall phenotypes in knockout mutants.« less

Immuno and Affinity Cytochemical Analysis of Cell Wall Composition in the Moss Physcomitrella patens.

PubMed

Berry, Elizabeth A; Tran, Mai L; Dimos, Christos S; Budziszek, Michael J; Scavuzzo-Duggan, Tess R; Roberts, Alison W

2016-01-01

In contrast to homeohydric vascular plants, mosses employ a poikilohydric strategy for surviving in the dry aerial environment. A detailed understanding of the structure, composition, and development of moss cell walls can contribute to our understanding of not only the evolution of overall cell wall complexity, but also the differences that have evolved in response to selection for different survival strategies. The model moss species Physcomitrella patens has a predominantly haploid lifecycle consisting of protonemal filaments that regenerate from protoplasts and enlarge by tip growth, and leafy gametophores composed of cells that enlarge by diffuse growth and differentiate into several different types. Advantages for genetic studies include methods for efficient targeted gene modification and extensive genomic resources. Immuno and affinity cytochemical labeling were used to examine the distribution of polysaccharides and proteins in regenerated protoplasts, protonemal filaments, rhizoids, and sectioned gametophores of P. patens. The cell wall composition of regenerated protoplasts was also characterized by flow cytometry. Crystalline cellulose was abundant in the cell walls of regenerating protoplasts and protonemal cells that developed on media of high osmolarity, whereas homogalactuonan was detected in the walls of protonemal cells that developed on low osmolarity media and not in regenerating protoplasts. Mannan was the major hemicellulose detected in all tissues tested. Arabinogalactan proteins were detected in different cell types by different probes, consistent with structural heterogneity. The results reveal developmental and cell type specific differences in cell wall composition and provide a basis for analyzing cell wall phenotypes in knockout mutants.

Immuno and Affinity Cytochemical Analysis of Cell Wall Composition in the Moss Physcomitrella patens

PubMed Central

Berry, Elizabeth A.; Tran, Mai L.; Dimos, Christos S.; Budziszek, Michael J.; Scavuzzo-Duggan, Tess R.; Roberts, Alison W.

2016-01-01

In contrast to homeohydric vascular plants, mosses employ a poikilohydric strategy for surviving in the dry aerial environment. A detailed understanding of the structure, composition, and development of moss cell walls can contribute to our understanding of not only the evolution of overall cell wall complexity, but also the differences that have evolved in response to selection for different survival strategies. The model moss species Physcomitrella patens has a predominantly haploid lifecycle consisting of protonemal filaments that regenerate from protoplasts and enlarge by tip growth, and leafy gametophores composed of cells that enlarge by diffuse growth and differentiate into several different types. Advantages for genetic studies include methods for efficient targeted gene modification and extensive genomic resources. Immuno and affinity cytochemical labeling were used to examine the distribution of polysaccharides and proteins in regenerated protoplasts, protonemal filaments, rhizoids, and sectioned gametophores of P. patens. The cell wall composition of regenerated protoplasts was also characterized by flow cytometry. Crystalline cellulose was abundant in the cell walls of regenerating protoplasts and protonemal cells that developed on media of high osmolarity, whereas homogalactuonan was detected in the walls of protonemal cells that developed on low osmolarity media and not in regenerating protoplasts. Mannan was the major hemicellulose detected in all tissues tested. Arabinogalactan proteins were detected in different cell types by different probes, consistent with structural heterogneity. The results reveal developmental and cell type specific differences in cell wall composition and provide a basis for analyzing cell wall phenotypes in knockout mutants. PMID:27014284

Evolution of Elemental Composition and Morphology in Fusion Reactor's First Wall

NASA Astrophysics Data System (ADS)

Kim, Yong W.

2007-11-01

Forcing of a multi-element alloy by a gradient field can modify the spatial profile of its elemental composition. The gradient field may be in the imposed temperature or the flux of impinging particles. In a fusion device, both scenarios apply. The consequences must be well understood because they change the thermal transport properties as well as the strength, corrosion and wear characteristics of the first wall materials. Given the large number of directions material evolution can take, new robust methods of near-surface composition analyses are needed. This paper presents a new measurement methodology and requisite instrumentation, which can provide measures of local elemental composition and transport properties simultaneously by time-resolved spectroscopy of laser-produced plasma (LPP) plume emissions from the specimen surfaces. The studies to date show that the composition profiles can be modified thermally in a reproducible manner; disparate thermal transport of constituent atoms can incur modifications of near-surface composition profiles.[Y.W. Kim, Int. J. Thermophysics 28, 732 (2007)] Also, disparate fluxes of fuel particles, fusion products and impurities force the first walls in myriad ways. Repetitive application of the LPP analysis can resolve the near-surface composition profile as well as transport properties over several microns with depth resolutions to 20 nm. Work supported in part by NSF-DMR.

Electrochemical detection and degradation of ibuprofen from water on multi-walled carbon nanotubes-epoxy composite electrode.

PubMed

Motoc, Sorina; Remes, Adriana; Pop, Aniela; Manea, Florica; Schoonman, Joop

2013-04-01

This work describes the electrochemical behaviour of ibuprofen on two types of multi-walled carbon nanotubes based composite electrodes, i.e., multi-walled carbon nanotubes-epoxy (MWCNT) and silver-modified zeolite-multi-walled carbon nanotubes-epoxy (AgZMWCNT) composites electrodes. The composite electrodes were obtained using two-roll mill procedure. SEM images of surfaces of the composites revealed a homogeneous distribution of the composite components within the epoxy matrix. AgZMWCNT composite electrode exhibited the better electrical conductivity and larger electroactive surface area. The electrochemical determination of ibuprofen (IBP) was achieved using AgZMWCNT by cyclic voltammetry, differential-pulsed voltammetry, square-wave voltammetry and chronoamperometry. The IBP degradation occurred on both composite electrodes under controlled electrolysis at 1.2 and 1.75 V vs. Ag/AgCl, and IBP concentration was determined comparatively by differential-pulsed voltammetry, under optimized conditions using AgZMWCNT electrode and UV-Vis spectrophotometry methods to determine the IBP degradation performance for each electrode. AgZMWCNT electrode exhibited a dual character allowing a double application in IBP degradation process and its control.

Lignin biosynthesis perturbations affect secondary cell wall composition and saccharification yield in Arabidopsis thaliana

PubMed Central

2013-01-01

Background Second-generation biofuels are generally produced from the polysaccharides in the lignocellulosic plant biomass, mainly cellulose. However, because cellulose is embedded in a matrix of other polysaccharides and lignin, its hydrolysis into the fermentable glucose is hampered. The senesced inflorescence stems of a set of 20 Arabidopsis thaliana mutants in 10 different genes of the lignin biosynthetic pathway were analyzed for cell wall composition and saccharification yield. Saccharification models were built to elucidate which cell wall parameters played a role in cell wall recalcitrance. Results Although lignin is a key polymer providing the strength necessary for the plant’s ability to grow upward, a reduction in lignin content down to 64% of the wild-type level in Arabidopsis was tolerated without any obvious growth penalty. In contrast to common perception, we found that a reduction in lignin was not compensated for by an increase in cellulose, but rather by an increase in matrix polysaccharides. In most lignin mutants, the saccharification yield was improved by up to 88% cellulose conversion for the cinnamoyl-coenzyme A reductase1 mutants under pretreatment conditions, whereas the wild-type cellulose conversion only reached 18%. The saccharification models and Pearson correlation matrix revealed that the lignin content was the main factor determining the saccharification yield. However, also lignin composition, matrix polysaccharide content and composition, and, especially, the xylose, galactose, and arabinose contents influenced the saccharification yield. Strikingly, cellulose content did not significantly affect saccharification yield. Conclusions Although the lignin content had the main effect on saccharification, also other cell wall factors could be engineered to potentially increase the cell wall processability, such as the galactose content. Our results contribute to a better understanding of the effect of lignin perturbations on plant cell

Polysaccharide compositions of collenchyma cell walls from celery (Apium graveolens L.) petioles.

PubMed

Chen, Da; Harris, Philip J; Sims, Ian M; Zujovic, Zoran; Melton, Laurence D

2017-06-15

Collenchyma serves as a mechanical support tissue for many herbaceous plants. Previous work based on solid-state NMR and immunomicroscopy suggested collenchyma cell walls (CWs) may have similar polysaccharide compositions to those commonly found in eudicotyledon parenchyma walls, but no detailed chemical analysis was available. In this study, compositions and structures of cell wall polysaccharides of peripheral collenchyma from celery petioles were investigated. This is the first detailed investigation of the cell wall composition of collenchyma from any plant. Celery petioles were found to elongate throughout their length during early growth, but as they matured elongation was increasingly confined to the upper region, until elongation ceased. Mature, fully elongated, petioles were divided into three equal segments, upper, middle and lower, and peripheral collenchyma strands isolated from each. Cell walls (CWs) were prepared from the strands, which also yielded a HEPES buffer soluble fraction. The CWs were sequentially extracted with CDTA, Na 2 CO 3 , 1 M KOH and 4 M KOH. Monosaccharide compositions of the CWs showed that pectin was the most abundant polysaccharide [with homogalacturonan (HG) more abundant than rhamnogalacturonan I (RG-I) and rhamnogalacturonan II (RG-II)], followed by cellulose, and other polysaccharides, mainly xyloglucans, with smaller amounts of heteroxylans and heteromannans. CWs from different segments had similar compositions, but those from the upper segments had slightly more pectin than those from the lower two segments. Further, the pectin in the CWs of the upper segment had a higher degree of methyl esterification than the other segments. In addition to the anticipated water-soluble pectins, the HEPES-soluble fractions surprisingly contained large amounts of heteroxylans. The CDTA and Na 2 CO 3 fractions were rich in HG and RG-I, the 1 M KOH fraction had abundant heteroxylans, the 4 M KOH fraction was rich in xyloglucan and

Sugar Lego: gene composition of bacterial carbohydrate metabolism genomic loci.

PubMed

Kaznadzey, Anna; Shelyakin, Pavel; Gelfand, Mikhail S

2017-11-25

Bacterial carbohydrate metabolism is extremely diverse, since carbohydrates serve as a major energy source and are involved in a variety of cellular processes. Bacterial genes belonging to same metabolic pathway are often co-localized in the chromosome, but it is not a strict rule. Gene co-localization in linked to co-evolution and co-regulation. This study focuses on a large-scale analysis of bacterial genomic loci related to the carbohydrate metabolism. We demonstrate that only 53% of 148,000 studied genes from over six hundred bacterial genomes are co-localized in bacterial genomes with other carbohydrate metabolism genes, which points to a significant role of singleton genes. Co-localized genes form cassettes, ranging in size from two to fifteen genes. Two major factors influencing the cassette-forming tendency are gene function and bacterial phylogeny. We have obtained a comprehensive picture of co-localization preferences of genes for nineteen major carbohydrate metabolism functional classes, over two hundred gene orthologous clusters, and thirty bacterial classes, and characterized the cassette variety in size and content among different species, highlighting a significant role of short cassettes. The preference towards co-localization of carbohydrate metabolism genes varies between 40 and 76% for bacterial taxa. Analysis of frequently co-localized genes yielded forty-five significant pairwise links between genes belonging to different functional classes. The number of such links per class range from zero to eight, demonstrating varying preferences of respective genes towards a specific chromosomal neighborhood. Genes from eleven functional classes tend to co-localize with genes from the same class, indicating an important role of clustering of genes with similar functions. At that, in most cases such co-localization does not originate from local duplication events. Overall, we describe a complex web formed by evolutionary relationships of bacterial

Reuteran and levan as carbohydrate sinks in transgenic sugarcane.

PubMed

Bauer, Rolene; Basson, Carin E; Bekker, Jan; Eduardo, Iban; Rohwer, Johann M; Uys, Lafras; van Wyk, Johannes H; Kossmann, Jens

2012-12-01

The present study reports the effect of high molecular weight bacterial fructan (levan) and glucan (reuteran) on growth and carbohydrate partitioning in transgenic sugarcane plants. These biopolymers are products of bacterial glycosyltransferases, enzymes that catalyze the polymerization of glucose or fructose residues from sucrose. Constructs, targeted to different subcellular compartments (cell wall and cytosol) and driven by the Cauliflower mosaic virus-35S: maize-ubiquitin promoter, were introduced into sugarcane by biolistic transformation. Polysaccharide accumulation severely affected growth of callus suspension cultures. Regeneration of embryonic callus tissue into plants proved problematic for cell wall-targeted lines. When targeted to the cytosol, only plants with relative low levels of biopolymer accumulation survived. In internodal stalk tissue that accumulate reuteran (max 0.03 mg/g FW), sucrose content (ca 60 mg/g FW) was not affected, while starch content (<0.4 mg/g FW) was increased up to four times. Total carbohydrate content was not significantly altered. On the other hand, starch and sucrose levels were significantly reduced in plants accumulating levan (max 0.01 mg/g FW). Heterologous expression resulted in a reduction in total carbohydrate assimilation rather than a simple diversion by competition for substrate.

Source, composition, and environmental implication of neutral carbohydrates in sediment cores of subtropical reservoirs, South China

NASA Astrophysics Data System (ADS)

Duan, Dandan; Zhang, Dainan; Yang, Yu; Wang, Jingfu; Chen, Jing'an; Ran, Yong

2017-09-01

Neutral monosaccharides, algal organic matter (AOM), and carbon stable isotope ratios in three sediment cores of various trophic reservoirs in South China were determined by high-performance anion-exchange chromatography, Rock-Eval pyrolysis, and Finnigan Delta Plus XL mass spectrometry, respectively. The carbon isotopic compositions were corrected for the Suess effect. The concentrations of total neutral carbohydrates (TCHO) range from 0.51 to 6.4 mg g-1 at mesotrophic reservoirs, and from 0.83 to 2.56 mg g-1 at an oligotrophic reservoir. Monosaccharide compositions and diagnostic parameters indicate a predominant contribution of phytoplankton in each of the three cores, which is consistent with the results inferred from the corrected carbon isotopic data and C/N ratios. The sedimentary neutral carbohydrates are likely to be structural polysaccharides and/or preserved in sediment minerals, which are resistant to degradation in the sediments. Moreover, the monosaccharide contents are highly related to the carbon isotopic data, algal productivity estimated from the hydrogen index, and increasing mean air temperature during the past 60 years. The nutrient input, however, is not a key factor affecting the primary productivity in the three reservoirs. The above evidence demonstrates that some of the resistant monosaccharides have been significantly elevated by climate change, even in low-latitude regions.

Fluorescent single walled nanotube/silica composite materials

DOEpatents

Dattelbaum, Andrew M.; Gupta, Gautam; Duque, Juan G.; Doorn, Stephen K.; Hamilton, Christopher E.; DeFriend Obrey, Kimberly A.

2013-03-12

Fluorescent composites of surfactant-wrapped single-walled carbon nanotubes (SWNTs) were prepared by exposing suspensions of surfactant-wrapped carbon nanotubes to tetramethylorthosilicate (TMOS) vapor. Sodium deoxycholate (DOC) and sodium dodecylsulphate (SDS) were the surfactants. No loss in emission intensity was observed when the suspension of DOC-wrapped SWNTs were exposed to the TMOS vapors, but about a 50% decrease in the emission signal was observed from the SDS-wrapped SWNTs nanotubes. The decrease in emission was minimal by buffering the SDS/SWNT suspension prior to forming the composite. Fluorescent xerogels were prepared by adding glycerol to the SWNT suspensions prior to TMOS vapor exposure, followed by drying the gels. Fluorescent aerogels were prepared by replacing water in the gels with methanol and then exposing them to supercritical fluid drying conditions. The aerogels can be used for gas sensing.

Phenotypic plasticity in cell walls of maize brown midrib mutants is limited by lignin composition

PubMed Central

Vermerris, Wilfred; Sherman, Debra M.; McIntyre, Lauren M.

2010-01-01

The hydrophobic cell wall polymer lignin is deposited in specialized cells to make them impermeable to water and prevent cell collapse as negative pressure or gravitational force is exerted. The variation in lignin subunit composition that exists among different species, and among different tissues within the same species suggests that lignin subunit composition varies depending on its precise function. In order to gain a better understanding of the relationship between lignin subunit composition and the physico-chemical properties of lignified tissues, detailed analyses were performed of near-isogenic brown midrib2 (bm2), bm4, bm2-bm4, and bm1-bm2-bm4 mutants of maize. This investigation was motivated by the fact that the bm2-bm4 double mutant is substantially shorter, displays drought symptoms even when well watered, and will often not develop reproductive organs, whereas the phenotypes of the individual bm single mutants and double mutant combinations other than bm2-bm4 are only subtly different from the wild-type control. Detailed cell wall compositional analyses revealed midrib-specific reductions in Klason lignin content in the bm2, bm4, and bm2-bm4 mutants relative to the wild-type control, with reductions in both guaiacyl (G)- and syringyl (S)-residues. The cellulose content was not different, but the reduction in lignin content was compensated by an increase in hemicellulosic polysaccharides. Linear discriminant analysis performed on the compositional data indicated that the bm2 and bm4 mutations act independently of each other on common cell wall biosynthetic steps. After quantitative analysis of scanning electron micrographs of midrib sections, the variation in chemical composition of the cell walls was shown to be correlated with the thickness of the sclerenchyma cell walls, but not with xylem vessel surface area. The bm2-bm4 double mutant represents the limit of phenotypic plasticity in cell wall composition, as the bm1-bm2-bm4 and bm2-bm3-bm4 mutants

Bioavailability of Carbohydrate Content in Natural and Transgenic Switchgrasses for the Extreme Thermophile Caldicellulosiruptor bescii

PubMed Central

Zurawski, Jeffrey V.; Khatibi, Piyum A.; Akinosho, Hannah O.; Straub, Christopher T.; Compton, Scott H.; Conway, Jonathan M.; Lee, Laura L.; Ragauskas, Arthur J.; Davison, Brian H.; Adams, Michael W. W.

2017-01-01

organism's access to the carbohydrate content of lignocellulose. Economically viable routes will characteristically minimize physical, chemical, and biological pretreatment such that microbial steps contribute to the greatest extent possible. Recently, transgenic versions of plants and trees have been developed with the intention of lowering the barrier to lignocellulose conversion, with particular focus on lignin content and composition. Here, the extremely thermophilic bacterium Caldicellulosiruptor bescii was used to solubilize natural and genetically modified switchgrass lines, with and without the aid of hydrothermal treatment. For lignocellulose conversion, it is clear that the microorganism, plant biomass substrate, and processing steps must all be considered simultaneously to achieve optimal results. Whether switchgrass lines engineered for low lignin or natural variants with desirable properties are used, conversion will depend on microbial access to crystalline cellulose in the plant cell wall. PMID:28625990

Identification of carbohydrate anomers using ion mobility-mass spectrometry.

PubMed

Hofmann, J; Hahm, H S; Seeberger, P H; Pagel, K

2015-10-08

Carbohydrates are ubiquitous biological polymers that are important in a broad range of biological processes. However, owing to their branched structures and the presence of stereogenic centres at each glycosidic linkage between monomers, carbohydrates are harder to characterize than are peptides and oligonucleotides. Methods such as nuclear magnetic resonance spectroscopy can be used to characterize glycosidic linkages, but this technique requires milligram amounts of material and cannot detect small amounts of coexisting isomers. Mass spectrometry, on the other hand, can provide information on carbohydrate composition and connectivity for even small amounts of sample, but it cannot be used to distinguish between stereoisomers. Here, we demonstrate that ion mobility-mass spectrometry--a method that separates molecules according to their mass, charge, size, and shape--can unambiguously identify carbohydrate linkage-isomers and stereoisomers. We analysed six synthetic carbohydrate isomers that differ in composition, connectivity, or configuration. Our data show that coexisting carbohydrate isomers can be identified, and relative concentrations of the minor isomer as low as 0.1 per cent can be detected. In addition, the analysis is rapid, and requires no derivatization and only small amounts of sample. These results indicate that ion mobility-mass spectrometry is an effective tool for the analysis of complex carbohydrates. This method could have an impact on the field of carbohydrate synthesis similar to that of the advent of high-performance liquid chromatography on the field of peptide assembly in the late 1970s.

Identification of carbohydrate anomers using ion mobility-mass spectrometry

NASA Astrophysics Data System (ADS)

Hofmann, J.; Hahm, H. S.; Seeberger, P. H.; Pagel, K.

2015-10-01

Carbohydrates are ubiquitous biological polymers that are important in a broad range of biological processes. However, owing to their branched structures and the presence of stereogenic centres at each glycosidic linkage between monomers, carbohydrates are harder to characterize than are peptides and oligonucleotides. Methods such as nuclear magnetic resonance spectroscopy can be used to characterize glycosidic linkages, but this technique requires milligram amounts of material and cannot detect small amounts of coexisting isomers. Mass spectrometry, on the other hand, can provide information on carbohydrate composition and connectivity for even small amounts of sample, but it cannot be used to distinguish between stereoisomers. Here, we demonstrate that ion mobility-mass spectrometry--a method that separates molecules according to their mass, charge, size, and shape--can unambiguously identify carbohydrate linkage-isomers and stereoisomers. We analysed six synthetic carbohydrate isomers that differ in composition, connectivity, or configuration. Our data show that coexisting carbohydrate isomers can be identified, and relative concentrations of the minor isomer as low as 0.1 per cent can be detected. In addition, the analysis is rapid, and requires no derivatization and only small amounts of sample. These results indicate that ion mobility-mass spectrometry is an effective tool for the analysis of complex carbohydrates. This method could have an impact on the field of carbohydrate synthesis similar to that of the advent of high-performance liquid chromatography on the field of peptide assembly in the late 1970s.

One-dimensional analysis of filamentary composite beam columns with thin-walled open sections

NASA Technical Reports Server (NTRS)

Lo, Patrick K.-L.; Johnson, Eric R.

1986-01-01

Vlasov's one-dimensional structural theory for thin-walled open section bars was originally developed and used for metallic elements. The theory was recently extended to laminated bars fabricated from advanced composite materials. The purpose of this research is to provide a study and assessment of the extended theory. The focus is on flexural and torsional-flexural buckling of thin-walled, open section, laminated composite columns. Buckling loads are computed from the theory using a linear bifurcation analysis and a geometrically nonlinear beam column analysis by the finite element method. Results from the analyses are compared to available test data.

Seasonal biochemical changes in composition of body wall tissues of sea cucumber Apostichopus japonicus

NASA Astrophysics Data System (ADS)

Gao, Fei; Xu, Qiang; Yang, Hongsheng

2011-03-01

Seasonal Variation in proximate, amino acid and fatty acid composition of the body wall of sea cucumber Apostichopus japonicus was evaluated. The proximate composition, except for ash content, changed significantly among seasons ( P<0.05). Alanine, glycine, glutamic acid and asparagic acid were the most abundant amino acids. Total amino acid and essential amino acid Contents both varied clearly with seasons ( P<0.05). 16:0 and 16:ln7 were the primary saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA) respectively for all months. EPA (20:5n-3), AA (20:4n-6) and DHA (22:6n-3) were the major polyunsaturated fatty acids (PUFA). The proportions of SFA and PUFA yielded significant seasonal variations ( P<0.001), but MUFA did not changed significantly. The results indicated that the biochemical compositions of the body wall in A. japonicus were significantly influenced by seasons and that the body wall tissue is an excellent source of protein, MUFA and n-3 PUFA for humans.

Endomembrane proteomics reveals putative enzymes involved in cell wall metabolism in wheat grain outer layers

PubMed Central

Chateigner-Boutin, Anne-Laure; Suliman, Muhtadi; Bouchet, Brigitte; Alvarado, Camille; Lollier, Virginie; Rogniaux, Hélène; Guillon, Fabienne; Larré, Colette

2015-01-01

Cereal grain outer layers fulfil essential functions for the developing seed such as supplying energy and providing protection. In the food industry, the grain outer layers called ‘the bran’ is valuable since it is rich in dietary fibre and other beneficial nutriments. The outer layers comprise several tissues with a high content in cell wall material. The cell wall composition of the grain peripheral tissues was investigated with specific probes at a stage of active cell wall synthesis. Considerable wall diversity between cell types was revealed. To identify the cellular machinery involved in cell wall synthesis, a subcellular proteomic approach was used targeting the Golgi apparatus where most cell wall polysaccharides are synthesized. The tissues were dissected into outer pericarp and intermediate layers where 822 and 1304 proteins were identified respectively. Many carbohydrate-active enzymes were revealed: some in the two peripheral grain fractions, others only in one tissue. Several protein families specific to one fraction and with characterized homologs in other species might be related to the specific detection of a polysaccharide in a particular cell layer. This report provides new information on grain cell walls and its biosynthesis in the valuable outer tissues, which are poorly studied so far. A better understanding of the mechanisms controlling cell wall composition could help to improve several quality traits of cereal products (e.g. dietary fibre content, biomass conversion to biofuel). PMID:25769308

Cell Wall Composition and Candidate Biosynthesis Gene Expression During Rice Development.

PubMed

Lin, Fan; Manisseri, Chithra; Fagerström, Alexandra; Peck, Matthew L; Vega-Sánchez, Miguel E; Williams, Brian; Chiniquy, Dawn M; Saha, Prasenjit; Pattathil, Sivakumar; Conlin, Brian; Zhu, Lan; Hahn, Michael G; Willats, William G T; Scheller, Henrik V; Ronald, Pamela C; Bartley, Laura E

2016-10-01

Cell walls of grasses, including cereal crops and biofuel grasses, comprise the majority of plant biomass and intimately influence plant growth, development and physiology. However, the functions of many cell wall synthesis genes, and the relationships among and the functions of cell wall components remain obscure. To better understand the patterns of cell wall accumulation and identify genes that act in grass cell wall biosynthesis, we characterized 30 samples from aerial organs of rice (Oryza sativa cv. Kitaake) at 10 developmental time points, 3-100 d post-germination. Within these samples, we measured 15 cell wall chemical components, enzymatic digestibility and 18 cell wall polysaccharide epitopes/ligands. We also used quantitative reverse transcription-PCR to measure expression of 50 glycosyltransferases, 15 acyltransferases and eight phenylpropanoid genes, many of which had previously been identified as being highly expressed in rice. Most cell wall components vary significantly during development, and correlations among them support current understanding of cell walls. We identified 92 significant correlations between cell wall components and gene expression and establish nine strong hypotheses for genes that synthesize xylans, mixed linkage glucan and pectin components. This work provides an extensive analysis of cell wall composition throughout rice development, identifies genes likely to synthesize grass cell walls, and provides a framework for development of genetically improved grasses for use in lignocellulosic biofuel production and agriculture. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Analysis and seismic tests of composite shear walls with CFST columns and steel plate deep beams

NASA Astrophysics Data System (ADS)

Dong, Hongying; Cao, Wanlin; Wu, Haipeng; Zhang, Jianwei; Xu, Fangfang

2013-12-01

A composite shear wall concept based on concrete filled steel tube (CFST) columns and steel plate (SP) deep beams is proposed and examined in this study. The new wall is composed of three different energy dissipation elements: CFST columns; SP deep beams; and reinforced concrete (RC) strips. The RC strips are intended to allow the core structural elements — the CFST columns and SP deep beams — to work as a single structure to consume energy. Six specimens of different configurations were tested under cyclic loading. The resulting data are analyzed herein. In addition, numerical simulations of the stress and damage processes for each specimen were carried out, and simulations were completed for a range of location and span-height ratio variations for the SP beams. The simulations show good agreement with the test results. The core structure exhibits a ductile yielding mechanism characteristic of strong column-weak beam structures, hysteretic curves are plump and the composite shear wall exhibits several seismic defense lines. The deformation of the shear wall specimens with encased CFST column and SP deep beam design appears to be closer to that of entire shear walls. Establishing optimal design parameters for the configuration of SP deep beams is pivotal to the best seismic behavior of the wall. The new composite shear wall is therefore suitable for use in the seismic design of building structures.

Effect of Yeast Cell Morphology, Cell Wall Physical Structure and Chemical Composition on Patulin Adsorption.

PubMed

Luo, Ying; Wang, Jianguo; Liu, Bin; Wang, Zhouli; Yuan, Yahong; Yue, Tianli

2015-01-01

The capability of yeast to adsorb patulin in fruit juice can aid in substantially reducing the patulin toxic effect on human health. This study aimed to investigate the capability of yeast cell morphology and cell wall internal structure and composition to adsorb patulin. To compare different yeast cell morphologies, cell wall internal structure and composition, scanning electron microscope, transmission electron microscope and ion chromatography were used. The results indicated that patulin adsorption capability of yeast was influenced by cell surface areas, volume, and cell wall thickness, as well as 1,3-β-glucan content. Among these factors, cell wall thickness and 1,3-β-glucan content serve significant functions. The investigation revealed that patulin adsorption capability was mainly affected by the three-dimensional network structure of the cell wall composed of 1,3-β-glucan. Finally, patulin adsorption in commercial kiwi fruit juice was investigated, and the results indicated that yeast cells could adsorb patulin from commercial kiwi fruit juice efficiently. This study can potentially simulate in vitro cell walls to enhance patulin adsorption capability and successfully apply to fruit juice industry.

Glucuronoyl esterase--novel carbohydrate esterase produced by Schizophyllum commune.

PubMed

Spániková, Silvia; Biely, Peter

2006-08-21

The cellulolytic system of the wood-rotting fungus Schizophyllum commune contains an esterase that hydrolyzes methyl ester of 4-O-methyl-d-glucuronic acid. The enzyme, called glucuronoyl esterase, was purified to electrophoretic homogeneity from a cellulose-spent culture fluid. Its substrate specificity was examined on a number of substrates of other carbohydrate esterases such as acetylxylan esterase, feruloyl esterase and pectin methylesterase. The glucuronoyl esterase attacks exclusively the esters of MeGlcA. The methyl ester of free or glycosidically linked MeGlcA was not hydrolysed by other carbohydrate esterases. The results suggest that we have discovered a new type of carbohydrate esterase that might be involved in disruption of ester linkages connecting hemicellulose and lignin in plant cell walls.

Genetic Resources for Maize Cell Wall Biology1[C][W][OA

PubMed Central

Penning, Bryan W.; Hunter, Charles T.; Tayengwa, Reuben; Eveland, Andrea L.; Dugard, Christopher K.; Olek, Anna T.; Vermerris, Wilfred; Koch, Karen E.; McCarty, Donald R.; Davis, Mark F.; Thomas, Steven R.; McCann, Maureen C.; Carpita, Nicholas C.

2009-01-01

Grass species represent a major source of food, feed, and fiber crops and potential feedstocks for biofuel production. Most of the biomass is contributed by cell walls that are distinct in composition from all other flowering plants. Identifying cell wall-related genes and their functions underpins a fundamental understanding of growth and development in these species. Toward this goal, we are building a knowledge base of the maize (Zea mays) genes involved in cell wall biology, their expression profiles, and the phenotypic consequences of mutation. Over 750 maize genes were annotated and assembled into gene families predicted to function in cell wall biogenesis. Comparative genomics of maize, rice (Oryza sativa), and Arabidopsis (Arabidopsis thaliana) sequences reveal differences in gene family structure between grass species and a reference eudicot species. Analysis of transcript profile data for cell wall genes in developing maize ovaries revealed that expression within families differed by up to 100-fold. When transcriptional analyses of developing ovaries before pollination from Arabidopsis, rice, and maize were contrasted, distinct sets of cell wall genes were expressed in grasses. These differences in gene family structure and expression between Arabidopsis and the grasses underscore the requirement for a grass-specific genetic model for functional analyses. A UniformMu population proved to be an important resource in both forward- and reverse-genetics approaches to identify hundreds of mutants in cell wall genes. A forward screen of field-grown lines by near-infrared spectroscopic screen of mature leaves yielded several dozen lines with heritable spectroscopic phenotypes. Pyrolysis-molecular beam mass spectrometry confirmed that several nir mutants had altered carbohydrate-lignin compositions. PMID:19926802

Deformation and Failure of a Multi-Wall Carbon Nanotube Yarn Composite

NASA Technical Reports Server (NTRS)

Gates, Thomas S.; Jefferson, Gail D.; Frankland, Sarah-Jane V.

2008-01-01

Forests of multi-walled carbon nanotubes can be twisted and manipulated into continuous fibers or yarns that exhibit many of the characteristics of traditional textiles. Macro-scale analysis and test may provide strength and stiffness predictions for a composite composed of a polymer matrix and low-volume fraction yarns. However, due to the nano-scale of the carbon nanotubes, it is desirable to use atomistic calculations to consider tube-tube interactions and the influence of simulated twist on the effective friction coefficient. This paper reports laboratory test data on the mechanical response of a multi-walled, carbon nanotube yarn/polymer composite from both dynamic and quasi-static tensile tests. Macroscale and nano-scale analysis methods are explored and used to define some of the key structure-property relationships. The measured influence of hot-wet aging on the tensile properties is also reported.

Free vibrations of thin-walled semicircular graphite-epoxy composite frames

NASA Technical Reports Server (NTRS)

Carden, Huey D.; Noor, Ahmed K.; Peters, Jeanne M.

1990-01-01

A detailed study is made of the effects of variations in lamination and material parameters of thin walled composite frames on their vibrational characteristics. The structures considered are semicircular thin walled frames with I and J sections. The flanges and webs of the frames are modeled by using 2-D shell and plate finite elements. A mixed formulation is used with the fundamental unknowns consisting of both the generalized displacements and stress resultants in the frame. The frequencies and modes predicted by the 2-D finite element model are compared with those obtained from experiments, as well as with the predictions of a non-dimensional thin walled beam finite element model. A detailed study is made of the sensitivity of the vibrational response to variations in the fiber orientation, material properties of the individual layers, and boundary conditions.

Free vibrations of thin-walled semicircular graphite-epoxy composite frames

NASA Technical Reports Server (NTRS)

Noor, Ahmed K.; Carden, Huey D.; Peters, Jeanne M.

1990-01-01

A detailed study is made of the effects of variations in lamination and material parameters of thin walled composite frames on their vibrational characteristics. The structures considered are semicircular thin walled frames with I and J sections. The flanges and webs of the frames are modelled by using 2-D shell and plate finite elements. A mixed formulation is used with the fundamental unknowns consisting of both the generalized displacements and stress resultants in the frames. The frequencies and modes predicted by the 2-D finite element model are compared with those obtained from experiments, as well as with the predictions of a 1-D thin walled beam finite element model. A detailed study is made of the sensitivity of the vibrational response to variations in the fiber orientation, material properties of the individual layers, and boundary conditions.

Carbohydrate composition, viscosity, solubility, and sensory acceptance of sweetpotato- and maize-based complementary foods

PubMed Central

Amagloh, Francis Kweku; Mutukumira, Anthony N.; Brough, Louise; Weber, Janet L.; Hardacre, Allan; Coad, Jane

2013-01-01

Background Cereal-based complementary foods from non-malted ingredients form a relatively high viscous porridge. Therefore, excessive dilution, usually with water, is required to reduce the viscosity to be appropriate for infant feeding. The dilution invariably leads to energy and nutrient thinning, that is, the reduction of energy and nutrient densities. Carbohydrate is the major constituent of food that significantly influences viscosity when heated in water. Objectives To compare the sweetpotato-based complementary foods (extrusion-cooked ComFa, roller-dried ComFa, and oven-toasted ComFa) and enriched Weanimix (maize-based formulation) regarding their 1) carbohydrate composition, 2) viscosity and water solubility index (WSI), and 3) sensory acceptance evaluated by sub-Sahara African women as model caregivers. Methods The level of simple sugars/carbohydrates was analysed by spectrophotometry, total dietary fibre by enzymatic-gravimetric method, and total carbohydrate and starch levels estimated by calculation. A Rapid Visco™ Analyser was used to measure viscosity. WSI was determined gravimetrically. A consumer sensory evaluation was used to evaluate the product acceptance of the roller-dried ComFa, oven-toasted ComFa, and enriched Weanimix. Results The sweetpotato-based complementary foods were, on average, significantly higher in maltose, sucrose, free glucose and fructose, and total dietary fibre, but they were markedly lower in starch content compared with the levels in the enriched Weanimix. Consequently, the sweetpotato-based complementary foods had relatively low apparent viscosity, and high WSI, than that of enriched Weanimix. The scores of sensory liking given by the caregivers were highest for the roller-dried ComFa, followed by the oven-toasted ComFa, and, finally, the enriched Weanimix. Conclusion The sweetpotato-based formulations have significant advantages as complementary food due to the high level of endogenous sugars and low starch content that

Bayesian decision and mixture models for AE monitoring of steel-concrete composite shear walls

NASA Astrophysics Data System (ADS)

Farhidzadeh, Alireza; Epackachi, Siamak; Salamone, Salvatore; Whittaker, Andrew S.

2015-11-01

This paper presents an approach based on an acoustic emission technique for the health monitoring of steel-concrete (SC) composite shear walls. SC composite walls consist of plain (unreinforced) concrete sandwiched between steel faceplates. Although the use of SC system construction has been studied extensively for nearly 20 years, little-to-no attention has been devoted to the development of structural health monitoring techniques for the inspection of damage of the concrete behind the steel plates. In this work an unsupervised pattern recognition algorithm based on probability theory is proposed to assess the soundness of the concrete infill, and eventually provide a diagnosis of the SC wall’s health. The approach is validated through an experimental study on a large-scale SC shear wall subjected to a displacement controlled reversed cyclic loading.

Carbohydrate Analysis: Can We Control the Ripening of Bananas?

NASA Astrophysics Data System (ADS)

Deal, S. Todd; Farmer, Catherine E.; Cerpovicz, Paul F.

2002-04-01

We have developed an experiment for nutritional/introductory biochemistry courses that focuses on carbohydrate analysis--specifically, the carbohydrates found in bananas and the change in carbohydrate composition as the banana ripens. Pairs of students analyze the starch and reducing sugar content of green, ripe, and overripe bananas. Using the techniques and knowledge gained from these analyses, they then investigate the influence of various storage methods on the ripening process. While this experiment was developed for an introductory-level biochemistry lab, it can easily be adapted for use in other laboratory programs that seek to teach the fundamentals of carbohydrate analysis.

Changes in cell wall polysaccharide composition, gene transcription and alternative splicing in germinating barley embryos.

PubMed

Zhang, Qisen; Zhang, Xiaoqi; Pettolino, Filomena; Zhou, Gaofeng; Li, Chengdao

2016-02-01

Barley (Hordeum vulgare L.) seed germination initiates many important biological processes such as DNA, membrane and mitochondrial repairs. However, little is known on cell wall modifications in germinating embryos. We have investigated cell wall polysaccharide composition change, gene transcription and alternative splicing events in four barley varieties at 24h and 48 h germination. Cell wall components in germinating barley embryos changed rapidly, with increases in cellulose and (1,3)(1,4)-β-D-glucan (20-100%) within 24h, but decreases in heteroxylan and arabinan (3-50%). There were also significant changes in the levels of type I arabinogalactans and heteromannans. Alternative splicing played very important roles in cell wall modifications. At least 22 cell wall transcripts were detected to undergo either alternative 3' splicing, alternative 5' splicing or intron retention type of alternative splicing. These genes coded enzymes catalyzing synthesis and degradation of cellulose, heteroxylan, (1,3)(1,4)-β-D-glucan and other cell wall polymers. Furthermore, transcriptional regulation also played very important roles in cell wall modifications. Transcript levels of primary wall cellulase synthase, heteroxylan synthesizing and nucleotide sugar inter-conversion genes were very high in germinating embryos. At least 50 cell wall genes changed transcript levels significantly. Expression patterns of many cell wall genes coincided with changes in polysaccharide composition. Our data showed that cell wall polysaccharide metabolism was very active in germinating barley embryos, which was regulated at both transcriptional and post-transcriptional levels. Copyright © 2015 Elsevier GmbH. All rights reserved.

Cell wall composition and biomass recalcitrance differences within a genotypically diverse set of Brachypodium distachyon inbred lines

DOE PAGES

Cass, Cynthia L.; Lavell, Anastasiya A.; Santoro, Nicholas; ...

2016-05-26

Brachypodium distachyon ( Brachypodium) has emerged as a useful model system for studying traits unique to graminaceous species including bioenergy crop grasses owing to its amenability to laboratory experimentation and the availability of extensive genetic and germplasm resources. Considerable natural variation has been uncovered for a variety of traits including flowering time, vernalization responsiveness, and above-ground growth characteristics. However, cell wall composition differences remain underexplored. Therefore, we assessed cell wall-related traits relevant to biomass conversion to biofuels in seven Brachypodium inbred lines that were chosen based on their high level of genotypic diversity as well as available genome sequences andmore » recombinant inbred line (RIL) populations. Senesced stems plus leaf sheaths from these lines exhibited significant differences in acetyl bromide soluble lignin (ABSL), cell wall polysaccharide-derived sugars, hydroxycinnamates content, and syringyl:guaiacyl:p-hydroxyphenyl (S:G:H) lignin ratios. Free glucose, sucrose, and starch content also differed significantly in senesced stems, as did the amounts of sugars released from cell wall polysaccharides (digestibility) upon exposure to a panel of thermochemical pretreatments followed by hydrolytic enzymatic digestion. Correlations were identified between inbred line lignin compositions and plant growth characteristics such as biomass accumulation and heading date (HD), and between amounts of cell wall polysaccharides and biomass digestibility. Finally, stem cell wall p-coumarate and ferulate contents and free-sugars content changed significantly with increased duration of vernalization for some inbred lines. Taken together, these results show that Brachypodium displays substantial phenotypic variation with respect to cell wall composition and biomass digestibility, with some compositional differences correlating with growth characteristics. Moreover, besides influencing

Cell wall composition and biomass recalcitrance differences within a genotypically diverse set of Brachypodium distachyon inbred lines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cass, Cynthia L.; Lavell, Anastasiya A.; Santoro, Nicholas

Brachypodium distachyon ( Brachypodium) has emerged as a useful model system for studying traits unique to graminaceous species including bioenergy crop grasses owing to its amenability to laboratory experimentation and the availability of extensive genetic and germplasm resources. Considerable natural variation has been uncovered for a variety of traits including flowering time, vernalization responsiveness, and above-ground growth characteristics. However, cell wall composition differences remain underexplored. Therefore, we assessed cell wall-related traits relevant to biomass conversion to biofuels in seven Brachypodium inbred lines that were chosen based on their high level of genotypic diversity as well as available genome sequences andmore » recombinant inbred line (RIL) populations. Senesced stems plus leaf sheaths from these lines exhibited significant differences in acetyl bromide soluble lignin (ABSL), cell wall polysaccharide-derived sugars, hydroxycinnamates content, and syringyl:guaiacyl:p-hydroxyphenyl (S:G:H) lignin ratios. Free glucose, sucrose, and starch content also differed significantly in senesced stems, as did the amounts of sugars released from cell wall polysaccharides (digestibility) upon exposure to a panel of thermochemical pretreatments followed by hydrolytic enzymatic digestion. Correlations were identified between inbred line lignin compositions and plant growth characteristics such as biomass accumulation and heading date (HD), and between amounts of cell wall polysaccharides and biomass digestibility. Finally, stem cell wall p-coumarate and ferulate contents and free-sugars content changed significantly with increased duration of vernalization for some inbred lines. Taken together, these results show that Brachypodium displays substantial phenotypic variation with respect to cell wall composition and biomass digestibility, with some compositional differences correlating with growth characteristics. Moreover, besides influencing

Polysaccharide composition of raw and cooked chayote (Sechium edule Sw.) fruits and tuberous roots.

PubMed

Shiga, Tânia M; Peroni-Okita, Fernanda Helena Gonçalves; Carpita, Nicholas C; Lajolo, Franco Maria; Cordenunsi, Beatriz Rosana

2015-10-05

Chayote is a multipurpose table vegetable widely consumed in Latin America countries. Chayote fruits, leaves and tuberous roots contain complex carbohydrates as dietary fiber and starch, vitamins and minerals. The complex polysaccharides (cell walls and starch) were analyzed in the black and green varieties of chayote fruits as well as in green chayote tuberous root before and after a controlled cooking process to assess changes in their composition and structure. The monosaccharide composition and linkage analysis indicated pectins homogalacturonans and rhamnogalacturonan I backbones constitute about 15-20% of the wall mass, but are heavily substituted with, up to 60% neutral arabinans, galactans, arabinogalactans. The remainder is composed of xyloglucan, glucomannans and galactoglucomannans. Chayote cell-wall polysaccharides are highly stable under normal cooking conditions, as confirmed by the optical microscopy of wall structure. We found also that tuberous roots constitute a valuable additional source of quality starch and fiber. Published by Elsevier Ltd.

Relationship between skin cell wall composition and anthocyanin extractability of Vitis vinifera L. cv. Tempranillo at different grape ripeness degree.

PubMed

Hernández-Hierro, José Miguel; Quijada-Morín, Natalia; Martínez-Lapuente, Leticia; Guadalupe, Zenaida; Ayestarán, Belén; Rivas-Gonzalo, Julián C; Escribano-Bailón, M Teresa

2014-03-01

The relationship between cell wall composition and extractability of anthocyanins from red grape skins was assessed in Tempranillo grape samples harvested at three stages of ripening (pre-harvest, harvest and over-ripening) and three different contents of soluble solids (22, 24 and 26 °Brix) within each stage. Cell wall material was isolated and analysed in order to determine cellulose, lignin, non-cellulosic polysaccharides, protein, total polyphenols index and the degree of esterification of pectins. Results showed the influence of ripeness degree and contents of soluble solids on cell wall composition. Furthermore, principal components analysis was applied to the obtained data set in order to establish relationships between cell wall composition and extractability of anthocyanins. Total insoluble material exhibits the biggest opposition to anthocyanin extraction, while the highest amounts of cellulose, rhamnogalacturonans-II and polyphenols were positively correlated with anthocyanin extraction. Moreover, multiple linear regression was performed to assess the influence of the cell wall composition on the extraction of anthocyanin compounds. A model connecting cell wall composition and anthocyanin extractabilities was built, explaining 96.2% of the observed variability. Copyright © 2013 Elsevier Ltd. All rights reserved.

Cell Wall Ultrastructure of Stem Wood, Roots, and Needles of a Conifer Varies in Response to Moisture Availability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pattathil, Sivakumar; Ingwers, Miles W.; Victoriano, Olivia L.

The composition, integrity, and architecture of the macromolecular matrix of cell walls, collectively referred to as cell wall ultrastructure, exhibits variation across species and organs and among cell types within organs. Indirect approaches have suggested that modifications to cell wall ultrastructure occur in response to abiotic stress; however, modifications have not been directly observed. Glycome profiling was used to study cell wall ultrastructure by examining variation in composition and extractability of non-cellulosic glycans in cell walls of stem wood, roots, and needles of loblolly pine saplings exposed to high and low soil moisture. Soil moisture influenced physiological processes and themore » overall composition and extractability of cell wall components differed as a function of soil moisture treatments. The strongest response of cell wall ultrastructure to soil moisture was increased extractability of pectic backbone epitopes in the low soil moisture treatment. The higher abundance of these pectic backbone epitopes in the oxalate extract indicate that the loosening of cell wall pectic components could be associated with the release of pectic signals as a stress response. The increased extractability of pectic backbone epitopes in response to low soil moisture availability was more pronounced in stem wood than in roots or needles. Additional responses to low soil moisture availability were observed in lignin associated carbohydrates released in chlorite extracts of stem wood, including an increased abundance of pectic arabinogalactan epitopes. Overall, these results indicate that cell walls of loblolly pine organs undergo changes in their ultrastructural composition and extractability as a response to soil moisture availability and that cell walls of the stem wood are more responsive to low soil moisture availability compared to cell walls of roots and needles. In conclusion, to our knowledge, this is the first direct evidence, delineated by

Cell Wall Ultrastructure of Stem Wood, Roots, and Needles of a Conifer Varies in Response to Moisture Availability.

PubMed

Pattathil, Sivakumar; Ingwers, Miles W; Victoriano, Olivia L; Kandemkavil, Sindhu; McGuire, Mary Anne; Teskey, Robert O; Aubrey, Doug P

2016-01-01

The composition, integrity, and architecture of the macromolecular matrix of cell walls, collectively referred to as cell wall ultrastructure, exhibits variation across species and organs and among cell types within organs. Indirect approaches have suggested that modifications to cell wall ultrastructure occur in response to abiotic stress; however, modifications have not been directly observed. Glycome profiling was used to study cell wall ultrastructure by examining variation in composition and extractability of non-cellulosic glycans in cell walls of stem wood, roots, and needles of loblolly pine saplings exposed to high and low soil moisture. Soil moisture influenced physiological processes and the overall composition and extractability of cell wall components differed as a function of soil moisture treatments. The strongest response of cell wall ultrastructure to soil moisture was increased extractability of pectic backbone epitopes in the low soil moisture treatment. The higher abundance of these pectic backbone epitopes in the oxalate extract indicate that the loosening of cell wall pectic components could be associated with the release of pectic signals as a stress response. The increased extractability of pectic backbone epitopes in response to low soil moisture availability was more pronounced in stem wood than in roots or needles. Additional responses to low soil moisture availability were observed in lignin-associated carbohydrates released in chlorite extracts of stem wood, including an increased abundance of pectic arabinogalactan epitopes. Overall, these results indicate that cell walls of loblolly pine organs undergo changes in their ultrastructural composition and extractability as a response to soil moisture availability and that cell walls of the stem wood are more responsive to low soil moisture availability compared to cell walls of roots and needles. To our knowledge, this is the first direct evidence, delineated by glycomic analyses, that

Cell Wall Ultrastructure of Stem Wood, Roots, and Needles of a Conifer Varies in Response to Moisture Availability

DOE PAGES

Pattathil, Sivakumar; Ingwers, Miles W.; Victoriano, Olivia L.; ...

2016-06-24

The composition, integrity, and architecture of the macromolecular matrix of cell walls, collectively referred to as cell wall ultrastructure, exhibits variation across species and organs and among cell types within organs. Indirect approaches have suggested that modifications to cell wall ultrastructure occur in response to abiotic stress; however, modifications have not been directly observed. Glycome profiling was used to study cell wall ultrastructure by examining variation in composition and extractability of non-cellulosic glycans in cell walls of stem wood, roots, and needles of loblolly pine saplings exposed to high and low soil moisture. Soil moisture influenced physiological processes and themore » overall composition and extractability of cell wall components differed as a function of soil moisture treatments. The strongest response of cell wall ultrastructure to soil moisture was increased extractability of pectic backbone epitopes in the low soil moisture treatment. The higher abundance of these pectic backbone epitopes in the oxalate extract indicate that the loosening of cell wall pectic components could be associated with the release of pectic signals as a stress response. The increased extractability of pectic backbone epitopes in response to low soil moisture availability was more pronounced in stem wood than in roots or needles. Additional responses to low soil moisture availability were observed in lignin associated carbohydrates released in chlorite extracts of stem wood, including an increased abundance of pectic arabinogalactan epitopes. Overall, these results indicate that cell walls of loblolly pine organs undergo changes in their ultrastructural composition and extractability as a response to soil moisture availability and that cell walls of the stem wood are more responsive to low soil moisture availability compared to cell walls of roots and needles. In conclusion, to our knowledge, this is the first direct evidence, delineated by

Electrical conductivity of multi-walled carbon nanotubes-SU8 epoxy composites

NASA Astrophysics Data System (ADS)

Grimaldi, Claudio; Mionić, Marijana; Gaal, Richard; Forró, László; Magrez, Arnaud

2013-06-01

We have characterized the electrical conductivity of the composite which consists of multi-walled carbon nanotubes dispersed in SU8 epoxy resin. Depending on the processing conditions of the epoxy (ranging from non-polymerized to cross-linked), we obtained tunneling and percolating-like regimes of the electrical conductivity of the composites. We interpret the observed qualitative change of the conductivity behavior in terms of reduced separation between the nanotubes induced by polymerization of the epoxy matrix.

Effect of Yeast Cell Morphology, Cell Wall Physical Structure and Chemical Composition on Patulin Adsorption

PubMed Central

Luo, Ying; Wang, Jianguo; Liu, Bin; Wang, Zhouli; Yuan, Yahong; Yue, Tianli

2015-01-01

The capability of yeast to adsorb patulin in fruit juice can aid in substantially reducing the patulin toxic effect on human health. This study aimed to investigate the capability of yeast cell morphology and cell wall internal structure and composition to adsorb patulin. To compare different yeast cell morphologies, cell wall internal structure and composition, scanning electron microscope, transmission electron microscope and ion chromatography were used. The results indicated that patulin adsorption capability of yeast was influenced by cell surface areas, volume, and cell wall thickness, as well as 1,3-β-glucan content. Among these factors, cell wall thickness and 1,3-β-glucan content serve significant functions. The investigation revealed that patulin adsorption capability was mainly affected by the three-dimensional network structure of the cell wall composed of 1,3-β-glucan. Finally, patulin adsorption in commercial kiwi fruit juice was investigated, and the results indicated that yeast cells could adsorb patulin from commercial kiwi fruit juice efficiently. This study can potentially simulate in vitro cell walls to enhance patulin adsorption capability and successfully apply to fruit juice industry. PMID:26295574

Chemical composition of the giant red sea cucumber, Parastichopus californicus, commercially harvested in Alaska

PubMed Central

Bechtel, Peter J; Oliveira, Alexandra CM; Demir, Necla; Smiley, Scott

2013-01-01

Giant red sea cucumbers, Parastichopus californicus, are commercially harvested in the U.S. Pacific Northwest; however, the nutritional and chemical properties of its edible muscle bands and body wall have not been fully elucidated. In particular are the fatty acid profiles of P. californicus tissues, which have not been documented. Sea cucumbers were delivered live and muscle bands and body wall freeze dried, vacuum packed, and stored at –30°C until analyzed. Proximate composition of freeze-dried tissues varied greatly with muscle bands being composed of 68% protein, 12% ash, 9% carbohydrate, and 5% lipids, while the body wall was composed of 47% protein, 26% ash, 15% carbohydrate, and 8% lipids. The hydroxyproline, proline, and glycine contents of the body wall were much higher than those in muscle bands, consistent with the larger amount of connective tissue. Calcium, magnesium, sodium, and iron contents were higher in the body wall than those in muscle bands, whereas the opposite was observed for zinc content. Total long-chain n-3 fatty acid contents were 19% and 32% of total fatty acids in body wall and muscle bands, respectively. Muscle bands had higher content of eicosapentaenoic acid (20:5n-3) than body wall at 22.6% and 12.3%, respectively. High content of arachidonic acid (20:4n-6) was recorded in both body wall (7.1%) and muscle bands (9.9%). Overall, the fatty acid profiles of body wall and muscle bands of P. californicus resemble those described for other species; however, the distribution and occurrence of certain fatty acids is unique to P. californicus, being representative of the fatty acid composition of temperate-polar marine organisms. The chemical characterization of freeze-dried edible tissues from P. californicus demonstrated that these products have valuable nutritional properties. The body wall, a food product of lower market value than muscle bands, could be better utilized for nutraceutical and pharmaceutical applications. PMID

Fem and Experimental Analysis of Thin-Walled Composite Elements Under Compression

NASA Astrophysics Data System (ADS)

Różyło, P.; Wysmulski, P.; Falkowicz, K.

2017-05-01

Thin-walled steel elements in the form of openwork columns with variable geometrical parameters of holes were studied. The samples of thin-walled composite columns were modelled numerically. They were subjected to axial compression to examine their behavior in the critical and post-critical state. The numerical models were articulately supported on the upper and lower edges of the cross-section of the profiles. The numerical analysis was conducted only with respect to the non-linear stability of the structure. The FEM analysis was performed until the material achieved its yield stress. This was done to force the loss of stability by the structures. The numerical analysis was performed using the ABAQUS® software. The numerical analysis was performed only for the elastic range to ensure the operating stability of the tested thin-walled structures.

Single walled carbon nanotube composites for bone tissue engineering.

PubMed

Gupta, Ashim; Woods, Mia D; Illingworth, Kenneth David; Niemeier, Ryan; Schafer, Isaac; Cady, Craig; Filip, Peter; El-Amin, Saadiq F

2013-09-01

The purpose of this study was to develop single walled carbon nanotubes (SWCNT) and poly lactic-co-glycolic acid (PLAGA) composites for orthopedic applications and to evaluate the interaction of human stem cells (hBMSCs) and osteoblasts (MC3T3-E1 cells) via cell growth, proliferation, gene expression, extracellular matrix production and mineralization. PLAGA and SWCNT/PLAGA composites were fabricated with various amounts of SWCNT (5, 10, 20, 40, and 100 mg), characterized and degradation studies were performed. Cells were seeded and cell adhesion/morphology, growth/survival, proliferation and gene expression analysis were performed to evaluate biocompatibility. Imaging studies demonstrated uniform incorporation of SWCNT into the PLAGA matrix and addition of SWCNT did not affect the degradation rate. Imaging studies revealed that MC3T3-E1 and hBMSCs cells exhibited normal, non-stressed morphology on the composites and all were biocompatible. Composites with 10 mg SWCNT resulted in highest rate of cell proliferation (p < 0.05) among all composites. Gene expression of alkaline phosphatase, collagen I, osteocalcin, osteopontin, Runx-2, and Bone Sialoprotein was observed on all composites. In conclusion, SWCNT/PLAGA composites imparted beneficial cellular growth capabilities and gene expression, and mineralization abilities were well established. These results demonstrate the potential of SWCNT/PLAGA composites for musculoskeletal regeneration and bone tissue engineering (BTE) and are promising for orthopedic applications. Copyright © 2013 Orthopaedic Research Society.

Regulation of Cell Wall Biogenesis in Saccharomyces cerevisiae: The Cell Wall Integrity Signaling Pathway

PubMed Central

Levin, David E.

2011-01-01

The yeast cell wall is a strong, but elastic, structure that is essential not only for the maintenance of cell shape and integrity, but also for progression through the cell cycle. During growth and morphogenesis, and in response to environmental challenges, the cell wall is remodeled in a highly regulated and polarized manner, a process that is principally under the control of the cell wall integrity (CWI) signaling pathway. This pathway transmits wall stress signals from the cell surface to the Rho1 GTPase, which mobilizes a physiologic response through a variety of effectors. Activation of CWI signaling regulates the production of various carbohydrate polymers of the cell wall, as well as their polarized delivery to the site of cell wall remodeling. This review article centers on CWI signaling in Saccharomyces cerevisiae through the cell cycle and in response to cell wall stress. The interface of this signaling pathway with other pathways that contribute to the maintenance of cell wall integrity is also discussed. PMID:22174182

The effect of growth medium on B. anthracis Sterne spore carbohydrate content.

PubMed

Colburn, Heather A; Wunschel, David S; Antolick, Kathryn C; Melville, Angela M; Valentine, Nancy B

2011-06-01

The expressed characteristics of biothreat agents may be impacted by variations in the culture environment, including growth medium formulation. The carbohydrate composition of B. anthracis spores has been well studied, particularly for the exosporium, which is the outermost spore structure. The carbohydrate composition of the exosporium has been demonstrated to be distinct from the vegetative form containing unique monosaccharides. We have investigated the carbohydrate composition of B. anthracis Sterne spores produced using four different medium types formulated with different sources of medium components. The amount of rhamnose, 3-O-methyl rhamnose and galactosamine was found to vary significantly between spores cultured using different medium formulations. The relative abundance of these monosaccharides compared to other monosaccharides such as mannosamine was also found to vary with medium type. Specific medium components were also found to impact the carbohydrate profile. Xylose has not been previously described in B. anthracis spores but was detected at low levels in two media. This may represent residual material from the brewery yeast extract used to formulate these two media. These results illustrate the utility of this method to capture the impact of growth medium on carbohydrate variation in spores. Detecting carbohydrate profiles in B. anthracis evidentiary material may provide useful forensic information on the growth medium used for sporulation. Copyright © 2011 Elsevier B.V. All rights reserved.

Recovery of insulin sensitivity and optimal body composition after rapid weight loss in obese dogs fed a high-protein medium-carbohydrate diet.

PubMed

André, A; Leriche, I; Chaix, G; Thorin, C; Burger, M; Nguyen, P

2017-06-01

This study investigated the effects of an experimental high-protein medium-carbohydrate diet (protein level, 46% metabolizable energy, ME). First, postprandial plasma glucose and insulin kinetics were determined in steady-state overweight/obese Beagle dogs (28%-41% excess body weight) for an experimental high-protein medium-carbohydrate diet (protein level, 46% ME) and a commercial high-carbohydrate medium-protein diet (protein level, 24%ME) in obese dogs. Secondly, all the dogs were included in a weight loss programme. They were fed the high-protein medium-carbohydrate diet, and the energy allocation was gradually reduced until they reached their optimal body weight. Insulin sensitivity and body composition were evaluated before and after weight loss using a euglycaemic-hyperinsulinaemic clamp and the deuterium oxide dilution technique respectively. For statistical analysis, linear mixed effect models were used with a significance level of 5%. Postprandial plasma glucose and insulin concentrations were substantially lower with the high-protein medium-carbohydrate diet than the high-carbohydrate medium-protein diet. These differences can be explained mainly by the difference in carbohydrate content between the two diets. Energy restriction (35% lower energy intake than in the obese state) resulted in a 2.23 ± 0.05% loss in body weight/week, and the dogs reached their optimal body weight in 12-16 weeks. Weight loss was associated with a significant increase in insulin sensitivity. The high-protein medium-carbohydrate diet allowed fat-free mass preservation despite a relatively high rate of weekly weight loss. The increase in insulin sensitivity indicated improved control of carbohydrate metabolism, possible due to weight loss and to the nature of the diet. Thus, a high-protein medium-carbohydrate diet is a good nutritional solution for managing the weight of overweight dogs. This diet may improve glycaemic control, which could be beneficial for preventing or

Evidence that family 35 carbohydrate binding modules display conserved specificity but divergent function

PubMed Central

Montanier, Cedric; van Bueren, Alicia Lammerts; Dumon, Claire; Flint, James E.; Correia, Marcia A.; Prates, Jose A.; Firbank, Susan J.; Lewis, Richard J.; Grondin, Gilles G.; Ghinet, Mariana G.; Gloster, Tracey M.; Herve, Cecile; Knox, J. Paul; Talbot, Brian G.; Turkenburg, Johan P.; Kerovuo, Janne; Brzezinski, Ryszard; Fontes, Carlos M. G. A.; Davies, Gideon J.; Boraston, Alisdair B.; Gilbert, Harry J.

2009-01-01

Enzymes that hydrolyze complex carbohydrates play important roles in numerous biological processes that result in the maintenance of marine and terrestrial life. These enzymes often contain noncatalytic carbohydrate binding modules (CBMs) that have important substrate-targeting functions. In general, there is a tight correlation between the ligands recognized by bacterial CBMs and the substrate specificity of the appended catalytic modules. Through high-resolution structural studies, we demonstrate that the architecture of the ligand binding sites of 4 distinct family 35 CBMs (CBM35s), appended to 3 plant cell wall hydrolases and the exo-β-d-glucosaminidase CsxA, which contributes to the detoxification and metabolism of an antibacterial fungal polysaccharide, is highly conserved and imparts specificity for glucuronic acid and/or Δ4,5-anhydrogalaturonic acid (Δ4,5-GalA). Δ4,5-GalA is released from pectin by the action of pectate lyases and as such acts as a signature molecule for plant cell wall degradation. Thus, the CBM35s appended to the 3 plant cell wall hydrolases, rather than targeting the substrates of the cognate catalytic modules, direct their appended enzymes to regions of the plant that are being actively degraded. Significantly, the CBM35 component of CsxA anchors the enzyme to the bacterial cell wall via its capacity to bind uronic acid sugars. This latter observation reveals an unusual mechanism for bacterial cell wall enzyme attachment. This report shows that the biological role of CBM35s is not dictated solely by their carbohydrate specificities but also by the context of their target ligands. PMID:19218457

Carbohydrates, proteins, cell surfaces, and the biochemistry of pathogenesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Albersheim, P.; Anderson-Prouty, A.J.

1975-01-01

General plant resistance to pathogenic attack by a myriad of microorganisms, viruses, nematodes, and insects are reviewed. Specifically discussed are: The role of the cell wall and wall-degrading enzymes in infective processes; an hypothesis to account for varietal specificity in gene-for-gene host-pathogen systems; examples which demonstrate that cell surface recognition phenomena are mediated through the interaction of carbohydrate-containing macromolecules and proteins; elicitors of phytoalexin production; and further consideration of the hypothesis and how the gene-for-gene relationship may have evolved. (JWP)

Cell wall compositional changes during incubation of plant roots measured by mid-infrared diffuse reflectance spectroscopy and fiber analysis

USDA-ARS?s Scientific Manuscript database

Plant roots, particularly the constituents of root cell walls (hemicellulose, cellulose and lignin), are important contributors to soil organic matter. Little is known about the cell wall composition of many important crop species or compositional changes as roots decay. The objectives of this stu...

Effects of aerobic exercise and dietary carbohydrate on energy expenditure and body composition during weight reduction in obese women.

PubMed

Racette, S B; Schoeller, D A; Kushner, R F; Neil, K M; Herling-Iaffaldano, K

1995-03-01

To test the benefits of aerobic exercise and dietary carbohydrate during reduced-energy feeding, 23 obese women (44 +/- 4% fat) were randomly assigned to either aerobic exercise (Ex) or no exercise (Nx), and to a low-fat (LF) or low-carbohydrate (LC) reducing diet (5.00 +/- 0.56 MJ/d) for 12 wk. Changes in body composition, postabsorptive resting metabolic rate (RMR), thermic effect of a meal (TEM), and total daily energy expenditure (TDEE) were measured by respiratory gas exchange and doubly labeled water. Significant effects of Ex included a greater loss of fat mass (Ex: -8.8 +/- 2.1 vs Nx: -6.1 +/- 2.3 kg, P = 0.008) and maintenance of TDEE (Ex: +0.07 +/- 1.23 vs Nx: -1.46 +/- 1.04 MJ/d, P = 0.004), due to a difference in physical activity (Ex: +0.75 +/- 1.06 vs Nx: -0.61 +/- 1.03 MJ/d, P = 0.006), which was not attributable solely to the Ex sessions. RMR in both groups decreased comparably (-0.54 MJ/d), and TEM (% of meal) did not change. Diet composition did not significantly influence body composition or energy expenditure changes, but a greater weight loss was observed after the LC than after the LF (-10.6 +/- 2.0 vs -8.1 +/- 3.0 kg, P = 0.037) diet. The addition of aerobic exercise to a low-energy diet was beneficial in the treatment of moderate obesity because of its favorable effects on body composition, physical activity, and TDEE.

An effective simplified model of composite compression struts for partially-restrained steel frame with reinforced concrete infill walls

NASA Astrophysics Data System (ADS)

Sun, Guohua; Chuang-Sheng, Walter Yang; Gu, Qiang; DesRoches, Reginald

2018-04-01

To resolve the issue regarding inaccurate prediction of the hysteretic behavior by micro-based numerical analysis for partially-restrained (PR) steel frames with solid reinforced concrete (RC) infill walls, an innovative simplified model of composite compression struts is proposed on the basis of experimental observation on the cracking distribution, load transferring mechanism, and failure modes of RC infill walls filled in PR steel frame. The proposed composite compression struts model for the solid RC infill walls is composed of α inclined struts and main diagonal struts. The α inclined struts are used to reflect the part of the lateral force resisted by shear connectors along the frame-wall interface, while the main diagonal struts are introduced to take into account the rest of the lateral force transferred along the diagonal direction due to the complicated interaction between the steel frame and RC infill walls. This study derives appropriate formulas for the effective widths of the α inclined strut and main diagonal strut, respectively. An example of PR steel frame with RC infill walls simulating simulated by the composite inclined compression struts model is illustrated. The maximum lateral strength and the hysteresis curve shape obtained from the proposed composite strut model are in good agreement with those from the test results, and the backbone curve of a PR steel frame with RC infill walls can be predicted precisely when the inter-story drift is within 1%. This simplified model can also predict the structural stiffness and the equivalent viscous damping ratio well when the inter-story drift ratio exceeds 0.5%.

Buckling of thin walled composite cylindrical shell filled with solid propellant

NASA Astrophysics Data System (ADS)

Dash, A. P.; Velmurugan, R.; Prasad, M. S. R.

2017-12-01

This paper investigates the buckling of thin walled composite cylindrical tubes that are partially filled with solid propellant equivalent elastic filler. Experimental investigation is conducted on thin composite tubes made out of S2-glass epoxy, which is made by using filament winding technique. The composite tubes are filled with elastic filler having similar mechanical properties as that of a typical solid propellant used in rocket motors. The tubes are tested for their buckling strength against the external pressure in the presence of the filler. Experimental data confirms the enhancement of external pressure carrying capacity of the composite tubes by up to three times as that of empty tubes for a volumetric loading fraction (VLF) of 0.9. Furthermore, the finite element based geometric nonlinearity analysis predicts the buckling behaviour of the partially filled composite tubes close to the experimental results.

Magnetic Property Measurements on Single Wall Carbon Nanotube-Polyimide Composites

NASA Technical Reports Server (NTRS)

Sun, Keun J.; Wincheski, Russell A.; Park, Cheol

2008-01-01

Temperature and magnetic field dependent magnetization measurements were performed on polyimide nanocomposite samples, synthesized with various weight percentages of single wall carbon nanotubes. It was found that the magnetization of the composite, normalized to the mass of nanotube material in the sample, decreased with increasing weight percentage of nanotubes. It is possible that the interfacial coupling between the carbon nanotube (CNT) fillers and the polyimide matrix promotes the diamagnetic response from CNTs and reduces the total magnetization of the composite. The coercivity of the samples, believed to originate from the residual magnetic catalyst particles, was enhanced and had a stronger temperature dependence as a result of the composite synthesis. These changes in magnetic properties can form the basis of a new approach to investigate the interfacial properties in the CNT nanocomposites through magnetic property measurements.

Thermoelectric properties of higher manganese silicide/multi-walled carbon nanotube composites.

PubMed

Truong, D Y Nhi; Kleinke, Holger; Gascoin, Franck

2014-10-28

Composites made of Higher Manganese Silicide (HMS)-based compound MnSi1.75Ge0.02 and multi-walled carbon nanotubes (MWCNTs) were prepared by an easy and effective method including mechanical milling under mild conditions and reactive spark plasma sintering. SEM compositional mappings show a homogeneous dispersion of MWCNTs in the HMS matrix. Electronic and thermal transport properties were measured from room temperature to 875 K. While power factors are virtually unchanged by the addition of MWCNTs, the lattice thermal conductivity is significantly reduced by about 30%. As a consequence, the maximum figure of merit for the composites with 1 wt% MWCNTs is improved by about 20% compared to the MWCNT free HMS-based sample.

Neutral carbohydrate geochemistry of particulate material in the central equatorial Pacific

NASA Astrophysics Data System (ADS)

Hernes, Peter J.; Hedges, John I.; Peterson, Michael L.; Wakeham, Stuart G.; Lee, Cindy

Neutral carbohydrate compositions were determined for particulate samples from plankton net tows, shallow floating sediment traps, mid-depth and deep moored sediment traps, and sediment cores collected along a north-south transect in the central equatorial Pacific Ocean during the U.S. JGOFS EqPac program. Total neutral carbohydrate depth profiles and patterns along the transect follow essentially the same trends as bulk and organic carbon (OC) fluxes—attenuating with depth, high near the equator and decreasing poleward. OC-normalized total aldose (TCH 2,O) yields along the transect and with depth do not show any consitent patterns. Relative to a planktonic source, neutral carbohydrate compositions in sediment trap and sediment core samples reflect preferential loss of ribose and storage carbohydrates rich in glucose, and preferential preservation of structural carbohydrates rich in rhamnose, xylose, fucose, and mannose. There is also evidence for an intermediately labile component rich in galactose. It appears that compositional signatures of neutral carbohydrates in sediments are more dependent upon their planktonic source than on any particular diagenetic pathway. Relative to other types of organic matter, neutral carbohydrates are better preserved in calcareous oozes from 12°S to 5°N than in red clays at 9°N based on OC-normalized TCH 2O yields, due to either differing sources or sorption characteristics. Weight per cent glucose generally decreases with increased degradation of organic material in the central equatorial Pacific region. Based on weight per cent glucose, comparisons of samples between Survey I (El Niõn) and Survey II (non-El Niño) indicate that during Survey I, organic material in the epipelagic zone in the northern hemisphere may have undergone more degradation than organic material in the southern hemisphere.

Behavior of thin-walled beams made of advanced composite materials and incorporating non-classical effects

NASA Astrophysics Data System (ADS)

Librescu, Liviu; Song, Ohseop

1991-11-01

Several results concerning the refined theory of thin-walled beams of arbitrary closed cross-section incorporating nonclassical effects are presented. These effects are related both with the exotic properties characterizing the advanced composite material structures and the nonuniform torsional model. A special case of the general equations is used to study several problems of cantilevered thin-walled beams and to assess the influence of the incorporated effects. The results presented in this paper could be useful toward a more rational design of aeronautical or aerospace constructions, as well as of helicopter or tilt rotor blades constructed of advanced composite materials.

Three-dimensional analysis of cavity wall deformation after composite restoration of masticatory teeth.

PubMed

Manchorova-Veleva, Neshka A

2011-01-01

The aim of the present work was to study the size of cavity wall deformation in eight class I and II defects after composite restoration. 1. Creating a geometric model - data on the size of the left maxillary second premolar were obtained from a routine craniofacial scanning of a 20-year-old patient with a 2,5 Dental CT scanner (General Electric), with high resolution and 0.625mm-thin slices. The contour of each of the 33 cross-sections of tooth 25 was delineated using graphics software (CorelDraw 7.0) and transferred to a specialized product for engineering design (SolidWorks Office Premium 2010, SolidWorks Corp. USA). The pulp cavity and periodontal ligament were created in the same manner and were integrated in the premolar body; 2. Generation of a finite element method - the geometric model was exported to specialized software for analysis by the finite element method - COSMOSWorks 2010, which automatically builds a 3D finite elements mesh. Based on the generated model, eight additional models of class I and II cavities with different geometries, adhesive layer and nanofilled composite restorations were constructed. The polymerization shrinkage was modelled by thermal deformation, with a negative temperature difference (cooling), corresponding to the actual volume shrinkage of the composite materials by 2.1%. In models A and B, the maximum cavity wall displacement was small - 0.014 mm and 0.015 mm, respectively. In models Al, B1, C1 and C, the displacement was at the expense of large deformation of the dental tissues. The maximum cavity wall displacements were 0.020 mm, 0.026 mm, 0.020 mm, 0.035 mm, respectively. The least cavity wall displacement was in models A2 and B2 with 0.008 mm and 0.017 mm, respectively. The least displacement resulting from cavity wall deformation is found in patient-friendly class I and II preparations. Preservation of the dental tissues reduces the risk of mechanical pressure on the dentinal lymph and the likelihood of post

Highly mobile ferroelastic domain walls in compositionally graded ferroelectric thin films

DOE PAGES

Damodaran, Anoop; Okatan, M. B.; Kacher, J.; ...

2016-02-15

Domains and domain walls are critical in determining the response of ferroelectrics, and the ability to controllably create, annihilate, or move domains is essential to enable a range of next-generation devices. Whereas electric-field control has been demonstrated for ferroelectric 180° domain walls, similar control of ferroelastic domains has not been achieved. Here, using controlled composition and strain gradients, we demonstrate deterministic control of ferroelastic domains that are rendered highly mobile in a controlled and reversible manner. Through a combination of thin-film growth, transmission-electron-microscopy-based nanobeam diffraction and nanoscale band-excitation switching spectroscopy, we show that strain gradients in compositionally graded PbZr 1-xTimore » xO 3 heterostructures stabilize needle-like ferroelastic domains that terminate inside the film. These needle-like domains are highly labile in the out-of-plane direction under applied electric fields, producing a locally enhanced piezoresponse. This work demonstrates the efficacy of novel modes of epitaxy in providing new modalities of domain engineering and potential for as-yet-unrealized nanoscale functional devices.« less

Highly mobile ferroelastic domain walls in compositionally graded ferroelectric thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Damodaran, Anoop; Okatan, M. B.; Kacher, J.

Domains and domain walls are critical in determining the response of ferroelectrics, and the ability to controllably create, annihilate, or move domains is essential to enable a range of next-generation devices. Whereas electric-field control has been demonstrated for ferroelectric 180° domain walls, similar control of ferroelastic domains has not been achieved. Here, using controlled composition and strain gradients, we demonstrate deterministic control of ferroelastic domains that are rendered highly mobile in a controlled and reversible manner. Through a combination of thin-film growth, transmission-electron-microscopy-based nanobeam diffraction and nanoscale band-excitation switching spectroscopy, we show that strain gradients in compositionally graded PbZr 1-xTimore » xO 3 heterostructures stabilize needle-like ferroelastic domains that terminate inside the film. These needle-like domains are highly labile in the out-of-plane direction under applied electric fields, producing a locally enhanced piezoresponse. This work demonstrates the efficacy of novel modes of epitaxy in providing new modalities of domain engineering and potential for as-yet-unrealized nanoscale functional devices.« less

POE/PLGA composite microspheres: formation and in vitro behavior of double walled microspheres.

PubMed

Yang, Yi-Yan; Shi, Meng; Goh, Suat-Hong; Moochhala, Shabbir M; Ng, Steve; Heller, Jorge

2003-03-07

The poly(ortho ester) (POE) and poly(D,L-lactide-co-glycolide) 50:50 (PLGA) composite microspheres were fabricated by a water-in-oil-in-water (w/o/w) double emulsion process. The morphology of the composite microspheres varied depending on POE content. When the POE content was 50, 60 or 70% in weight, the double walled microspheres with a dense core of POE and a porous shell of PLGA were formed. The formation of the double walled POE/PLGA microspheres was analysed. Their in vitro degradation behavior was characterized by scanning electron microscopy, gel permeation chromatography, Fourier-transform infrared microscopy and nuclear magnetic resonance spectroscopy (NMR). It was found that compared to the neat POE or PLGA microspheres, distinct degradation mechanism was achieved in the double walled POE/PLGA microspheres system. The degradation of the POE core was accelerated due to the acidic microenvironment produced by the hydrolysis of the outer PLGA layer. The formation of hollow microspheres became pronounced after the first week in vitro. 1H NMR spectra showed that the POE core was completely degraded after 4 weeks. On the other hand, the outer PLGA layer experienced slightly retarded degradation after the POE core disappeared. PLGA in the double walled microspheres kept more than 32% of its initial molecular weight over a period of 7 weeks.

Highly Stable and Flexible Pressure Sensors with Modified Multi-Walled Carbon Nanotube/Polymer Composites for Human Monitoring.

PubMed

He, Yin; Ming, Yue; Li, Wei; Li, Yafang; Wu, Maoqi; Song, Jinzhong; Li, Xiaojiu; Liu, Hao

2018-04-26

A facile method for preparing an easy processing, repeatable and flexible pressure sensor was presented via the synthesis of modified multi-walled carbon nanotubes (m-MWNTs) and polyurethane (PU) films. The surface modification of multi-walled carbon nanotubes (MWNTs) simultaneously used a silane coupling agent (KH550) and sodium dodecyl benzene sulfonate (SDBS) to improve the dispersibility and compatibility of the MWNTs in a polymer matrix. The electrical property and piezoresistive behavior of the m-MWNT/PU composites were compared with raw multi-walled carbon nanotube (raw MWNT)/PU composites. Under linear uniaxial pressure, the m-MWNT/PU composite exhibited 4.282%kPa −1 sensitivity within the pressure of 1 kPa. The nonlinear error, hysteresis error and repeatability error of the piezoresistivity of m-MWNT/PU decreased 9%, 16.72% and 54.95% relative to raw MWNT/PU respectively. Therefore, the piezoresistive response of m-MWNT/PU had better stability than that of raw MWNT/PU composites. The m-MWNT/PU sensors could be utilized in wearable devices for body movement detection, monitoring of respiration and pressure detection in garments.

Effective load transfer by a chromium carbide nanostructure in a multi-walled carbon nanotube/copper matrix composite

NASA Astrophysics Data System (ADS)

Cho, Seungchan; Kikuchi, Keiko; Kawasaki, Akira; Kwon, Hansang; Kim, Yangdo

2012-08-01

Multi-walled carbon nanotube (MWCNT) reinforced copper (Cu) matrix composites, which exhibit chromium (Cr) carbide nanostructures at the MWCNT/Cu interface, were prepared through a carbide formation using CuCr alloy powder. The fully densified and oriented MWCNTs dispersed throughout the composites were prepared using spark plasma sintering (SPS) followed by hot extrusion. The tensile strengths of the MWCNT/CuCr composites increased with increasing MWCNTs content, while the tensile strength of MWCNT/Cu composite decreased from that of monolithic Cu. The enhanced tensile strength of the MWCNT/CuCr composites is a result of possible load-transfer mechanisms of the interfacial Cr carbide nanostructures. The multi-wall failure of MWCNTs observed in the fracture surface of the MWCNT/CuCr composites indicates an improvement in the load-bearing capacity of the MWCNTs. This result shows that the Cr carbide nanostructures effectively transferred the tensile load to the MWCNTs during fracture through carbide nanostructure formation in the MWCNT/Cu composite.

Phylogenetic Diversity in the Macromolecular Composition of Microalgae

PubMed Central

Finkel, Zoe V.; Follows, Mick J.; Liefer, Justin D.; Brown, Chris M.; Benner, Ina; Irwin, Andrew J.

2016-01-01

The elemental stoichiometry of microalgae reflects their underlying macromolecular composition and influences competitive interactions among species and their role in the food web and biogeochemistry. Here we provide a new estimate of the macromolecular composition of microalgae using a hierarchical Bayesian analysis of data compiled from the literature. The median macromolecular composition of nutrient-sufficient exponentially growing microalgae is 32.2% protein, 17.3% lipid, 15.0% carbohydrate, 17.3% ash, 5.7% RNA, 1.1% chlorophyll-a and 1.0% DNA as percent dry weight. Our analysis identifies significant phylogenetic differences in macromolecular composition undetected by previous studies due to small sample sizes and the large inherent variability in macromolecular pools. The phylogenetic differences in macromolecular composition lead to variations in carbon-to-nitrogen ratios that are consistent with independent observations. These phylogenetic differences in macromolecular and elemental composition reflect adaptations in cellular architecture and biochemistry; specifically in the cell wall, the light harvesting apparatus, and storage pools. PMID:27228080

Single-walled carbon nanotubes/polymer composite electrodes patterned directly from solution.

PubMed

Chang, Jingbo; Najeeb, Choolakadavil Khalid; Lee, Jae-Hyeok; Kim, Jae-Ho

2011-06-07

This work describes a simple technique for direct patterning of single-walled carbon nanotube (SWNT)/poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS) composite electrodes in a large area on a substrate based on the solution transfer process by microcontact printing using poly(dimethylsiloxane) (PDMS) stamps. Various shapes of SWNT/PEDOT-PSS composite patterns, such as line, circle, and square, can be easily fabricated with high pattern fidelity and structural integrity. The single parallel line pattern device exhibits high electrical conductivity (0.75 × 10(5) S/m) and electronic stability because of alignment of nanotubes and big-size SWNT bundles (∼5 nm). The electromechanical study reveals that the composite patterns show ∼1% resistance change along SWNT alignment direction and ∼5% resistance change along vertical alignment direction after 200 bend cycles. Our approach provides a facile, low-cost method to pattern transparent conductive SWNT/polymer composite electrodes and demonstrates a novel platform for future integration of conducting SWNT/polymer composite patterns for optoelectronic applications.

A comparison of low-carbohydrate vs. high-carbohydrate diets: energy restriction, nutrient quality and correlation to body mass index.

PubMed

Bowman, Shanthy A; Spence, Joseph T

2002-06-01

To evaluate free-living adults' diets that ranged from very low to high amounts of carbohydrate for their energy content, nutritional quality and correlation to Body Mass Index. Adults ages 19 years and older, who had complete dietary intake data on day-1 of the USDA's 1994 to 1996 Continuing Survey of Food Intakes by Individuals (CSFII 1994-1996), were divided into four groups--very low, low, moderate and high carbohydrate--based on the percent total energy from carbohydrate. Mean energy, nutrient, food intakes and Body Mass Index values were compared among the groups. SUDAAN software package was used for the data analysis and pair-wise mean comparisons (p < 0.05). The high-carbohydrate diet was lower in energy and energy density (number of kilocalories per gram of total amount of food consumed) than the other three diets. Macronutrient composition varied significantly among all the four groups. Nutrient density (amount of nutrient per 1,000 kilocalories of energy consumed) of vitamin A, carotene, vitamin C, folate, calcium, magnesium and iron increased and that of vitamin B12 and zinc decreased with an increase in the percent total energy from carbohydrate. The high-carbohydrate group ate more of low-fat foods, grain products and fruits. This group also had the lowest sodium intake. Adults eating a high-carbohydrate diet are more likely to have Body Mass Index values below 25. A study of diets of free-living adults in the U.S. showed that diets high in carbohydrate were both energy restrictive and nutritious and may be adopted for successful weight management.

Flow Kills Conductivity of Single Wall Carbon Nanotubes (SWNT) Composites

NASA Astrophysics Data System (ADS)

Bhatt, Sanjiv; Macosko, Christopher

2006-03-01

Most composites of polymer and single wall carbon nanotubes (SWNT) reported in the literature are made by solvent casting or simple compression molding. Commercial utility of these composites requires use of precision injection molding. We have observed a unique behavior wherein the SWNT composites made by injection molding or by extrusion are insulators but upon heating become electrically conductive. This behavior appears to be the result of a relaxation phenomenon in the SWNT composite. During flow into an injection mold or through an extrusion die the well-dispersed SWNT in the polymer matrix tend to align such that they are not in contact with each other and are farther than the minimum required distance, 5 nm (1), to achieve electrical percolation through electron hopping. Upon heating the SWNT relax and either touch each other or are at a distance less than or equal to 5 nm from each other to create a percolating. [1] Du, F., Scogna, R, C., Zhou, W., Brand, Stijn, Fischer, J. E., and Winey, K. I., Macromolecules 2004, 37, 9048-9055.

N-acetylglucosamine affects Cryptococcus neoformans cell-wall composition and melanin architecture.

PubMed

Camacho, Emma; Chrissian, Christine; Cordero, Radames J B; Liporagi-Lopes, Livia; Stark, Ruth E; Casadevall, Arturo

2017-11-01

Cryptococcus neoformans is an environmental fungus that belongs to the phylum Basidiomycetes and is a major pathogen in immunocompromised patients. The ability of C. neoformans to produce melanin pigments represents its second most important virulence factor, after the presence of a polysaccharide capsule. Both the capsule and melanin are closely associated with the fungal cell wall, a complex structure that is essential for maintaining cell morphology and viability under conditions of stress. The amino sugar N-acetylglucosamine (GlcNAc) is a key constituent of the cell-wall chitin and is used for both N-linked glycosylation and GPI anchor synthesis. Recent studies have suggested additional roles for GlcNAc as an activator and mediator of cellular signalling in fungal and plant cells. Furthermore, chitin and chitosan polysaccharides interact with melanin pigments in the cell wall and have been found to be essential for melanization. Despite the importance of melanin, its molecular structure remains unresolved; however, we previously obtained critical insights using advanced nuclear magnetic resonance (NMR) and imaging techniques. In this study, we investigated the effect of GlcNAc supplementation on cryptococcal cell-wall composition and melanization. C. neoformans was able to metabolize GlcNAc as a sole source of carbon and nitrogen, indicating a capacity to use a component of a highly abundant polymer in the biospherenutritionally. C. neoformans cells grown with GlcNAc manifested changes in the chitosan cell-wall content, cell-wall thickness and capsule size. Supplementing cultures with isotopically 15 N-labelled GlcNAc demonstrated that the exogenous monomer serves as a building block for chitin/chitosan and is incorporated into the cell wall. The altered chitin-to-chitosan ratio had no negative effects on the mother-daughter cell separation; growth with GlcNAc affected the fungal cell-wall scaffold, resulting in increased melanin deposition and assembly. In

N-acetylglucosamine affects Cryptococcus neoformans cell-wall composition and melanin architecture

PubMed Central

Camacho, Emma; Chrissian, Christine; Cordero, Radames J. B.; Liporagi-Lopes, Livia; Stark, Ruth E.; Casadevall, Arturo

2017-01-01

Cryptococcus neoformans is an environmental fungus that belongs to the phylum Basidiomycetes and is a major pathogen in immunocompromised patients. The ability of C. neoformans to produce melanin pigments represents its second most important virulence factor, after the presence of a polysaccharide capsule. Both the capsule and melanin are closely associated with the fungal cell wall, a complex structure that is essential for maintaining cell morphology and viability under conditions of stress. The amino sugar N-acetylglucosamine (GlcNAc) is a key constituent of the cell-wall chitin and is used for both N-linked glycosylation and GPI anchor synthesis. Recent studies have suggested additional roles for GlcNAc as an activator and mediator of cellular signalling in fungal and plant cells. Furthermore, chitin and chitosan polysaccharides interact with melanin pigments in the cell wall and have been found to be essential for melanization. Despite the importance of melanin, its molecular structure remains unresolved; however, we previously obtained critical insights using advanced nuclear magnetic resonance (NMR) and imaging techniques. In this study, we investigated the effect of GlcNAc supplementation on cryptococcal cell-wall composition and melanization. C. neoformans was able to metabolize GlcNAc as a sole source of carbon and nitrogen, indicating a capacity to use a component of a highly abundant polymer in the biospherenutritionally. C. neoformans cells grown with GlcNAc manifested changes in the chitosan cell-wall content, cell-wall thickness and capsule size. Supplementing cultures with isotopically 15N-labelled GlcNAc demonstrated that the exogenous monomer serves as a building block for chitin/chitosan and is incorporated into the cell wall. The altered chitin-to-chitosan ratio had no negative effects on the mother–daughter cell separation; growth with GlcNAc affected the fungal cell-wall scaffold, resulting in increased melanin deposition and assembly. In

Carbohydrate and exercise performance: the role of multiple transportable carbohydrates.

PubMed

Jeukendrup, Asker E

2010-07-01

Carbohydrate feeding has been shown to be ergogenic, but recently substantial advances have been made in optimizing the guidelines for carbohydrate intake during prolonged exercise. It was found that limitations to carbohydrate oxidation were in the absorptive process most likely because of a saturation of carbohydrate transporters. By using a combination of carbohydrates that use different intestinal transporters for absorption it was shown that carbohydrate delivery and oxidation could be increased. Studies demonstrated increases in exogenous carbohydrate oxidation rates of up to 65% of glucose: fructose compared with glucose only. Exogenous carbohydrate oxidation rates reach values of 1.75 g/min whereas previously it was thought that 1 g/min was the absolute maximum. The increased carbohydrate oxidation with multiple transportable carbohydrates was accompanied by increased fluid delivery and improved oxidation efficiency, and thus the likelihood of gastrointestinal distress may be diminished. Studies also demonstrated reduced fatigue and improved exercise performance with multiple transportable carbohydrates compared with a single carbohydrate. Multiple transportable carbohydrates, ingested at high rates, can be beneficial during endurance sports in which the duration of exercise is 3 h or more.

Randomized controlled trial of changes in dietary carbohydrate/fat ratio and simple vs complex carbohydrates on body weight and blood lipids: the CARMEN study. The Carbohydrate Ratio Management in European National diets.

PubMed

Saris, W H; Astrup, A; Prentice, A M; Zunft, H J; Formiguera, X; Verboeket-van de Venne, W P; Raben, A; Poppitt, S D; Seppelt, B; Johnston, S; Vasilaras, T H; Keogh, G F

2000-10-01

To investigate the long-term effects of changes in dietary carbohydrate/fat ratio and simple vs complex carbohydrates. Randomized controlled multicentre trial (CARMEN), in which subjects were allocated for 6 months either to a seasonal control group (no intervention) or to one of three experimental groups: a control diet group (dietary intervention typical of the average national intake); a low-fat high simple carbohydrate group; or a low-fat high complex carbohydrate group. Three hundred and ninety eight moderately obese adults. The change in body weight was the primary outcome; changes in body composition and blood lipids were secondary outcomes. Body weight loss in the low-fat high simple carbohydrate and low-fat high complex carbohydrate groups was 0.9 kg (P < 0.05) and 1.8 kg (P < 0.001), while the control diet and seasonal control groups gained weight (0.8 and 0.1 kg, NS). Fat mass changed by -1.3kg (P< 0.01), -1.8kg (P< 0.001) and +0.6kg (NS) in the low-fat high simple carbohydrate, low-fat high complex carbohydrate and control diet groups, respectively. Changes in blood lipids did not differ significantly between the dietary treatment groups. Our findings suggest that reduction of fat intake results in a modest but significant reduction in body weight and body fatness. The concomitant increase in either simple or complex carbohydrates did not indicate significant differences in weight change. No adverse effects on blood lipids were observed. These findings underline the importance of this dietary change and its potential impact on the public health implications of obesity.

Highly Stable and Flexible Pressure Sensors with Modified Multi-Walled Carbon Nanotube/Polymer Composites for Human Monitoring

PubMed Central

He, Yin; Ming, Yue; Li, Wei; Li, Yafang; Wu, Maoqi; Song, Jinzhong; Li, Xiaojiu; Liu, Hao

2018-01-01

A facile method for preparing an easy processing, repeatable and flexible pressure sensor was presented via the synthesis of modified multi-walled carbon nanotubes (m-MWNTs) and polyurethane (PU) films. The surface modification of multi-walled carbon nanotubes (MWNTs) simultaneously used a silane coupling agent (KH550) and sodium dodecyl benzene sulfonate (SDBS) to improve the dispersibility and compatibility of the MWNTs in a polymer matrix. The electrical property and piezoresistive behavior of the m-MWNT/PU composites were compared with raw multi-walled carbon nanotube (raw MWNT)/PU composites. Under linear uniaxial pressure, the m-MWNT/PU composite exhibited 4.282%kPa−1 sensitivity within the pressure of 1 kPa. The nonlinear error, hysteresis error and repeatability error of the piezoresistivity of m-MWNT/PU decreased 9%, 16.72% and 54.95% relative to raw MWNT/PU respectively. Therefore, the piezoresistive response of m-MWNT/PU had better stability than that of raw MWNT/PU composites. The m-MWNT/PU sensors could be utilized in wearable devices for body movement detection, monitoring of respiration and pressure detection in garments. PMID:29701643

Aerobic Exercise Training Adaptations Are Increased by Postexercise Carbohydrate-Protein Supplementation

PubMed Central

Ferguson-Stegall, Lisa; McCleave, Erin; Ding, Zhenping; Doerner III, Phillip G.; Liu, Yang; Wang, Bei; Healy, Marin; Kleinert, Maximilian; Dessard, Benjamin; Lassiter, David G.; Kammer, Lynne; Ivy, John L.

2011-01-01

Carbohydrate-protein supplementation has been found to increase the rate of training adaptation when provided postresistance exercise. The present study compared the effects of a carbohydrate and protein supplement in the form of chocolate milk (CM), isocaloric carbohydrate (CHO), and placebo on training adaptations occurring over 4.5 weeks of aerobic exercise training. Thirty-two untrained subjects cycled 60 min/d, 5 d/wk for 4.5 wks at 75–80% of maximal oxygen consumption (VO2 max). Supplements were ingested immediately and 1 h after each exercise session. VO2 max and body composition were assessed before the start and end of training. VO2 max improvements were significantly greater in CM than CHO and placebo. Greater improvements in body composition, represented by a calculated lean and fat mass differential for whole body and trunk, were found in the CM group compared to CHO. We conclude supplementing with CM postexercise improves aerobic power and body composition more effectively than CHO alone. PMID:21773022

Cell wall composition profiling of parasitic giant dodder (Cuscuta reflexa) and its hosts: a priori differences and induced changes.

PubMed

Johnsen, Hanne R; Striberny, Bernd; Olsen, Stian; Vidal-Melgosa, Silvia; Fangel, Jonatan U; Willats, William G T; Rose, Jocelyn K C; Krause, Kirsten

2015-08-01

Host plant penetration is the gateway to survival for holoparasitic Cuscuta and requires host cell wall degradation. Compositional differences of cell walls may explain why some hosts are amenable to such degradation while others can resist infection. Antibody-based techniques for comprehensive profiling of cell wall epitopes and cell wall-modifying enzymes were applied to several susceptible hosts and a resistant host of Cuscuta reflexa and to the parasite itself. Infected tissue of Pelargonium zonale contained high concentrations of de-esterified homogalacturonans in the cell walls, particularly adjacent to the parasite's haustoria. High pectinolytic activity in haustorial extracts and high expression levels of pectate lyase genes suggest that the parasite contributes directly to wall remodeling. Mannan and xylan concentrations were low in P. zonale and in five susceptible tomato introgression lines, but high in the resistant Solanum lycopersicum cv M82, and in C. reflexa itself. Knowledge of the composition of resistant host cell walls and the parasite's own cell walls is useful in developing strategies to prevent infection by parasitic plants. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Effect of growth conditions on production of rhamnose-containing cell wall and capsular polysaccharides by strains of Lactobacillus casei subsp. rhamnosus.

PubMed

Wicken, A J; Ayres, A; Campbell, L K; Knox, K W

1983-01-01

Strains of Lactobacillus casei subsp. rhamnosus possessing two cell wall polysaccharides, a hexosamine-containing H-polysaccharide and a rhamnose-containing R-polysaccharide, were examined for the effect of growth conditions on the production of these two components. In strain NCTC 6375, R- and H-polysaccharides accounted for an estimated 44 and 20%, respectively, of the cell wall for organisms grown in batch culture with glucose as the carbohydrate source. Growth on fructose-containing media reduced the amount of R-polysaccharide by approximately 50% without affecting the amount of H-polysaccharide. Subculture of fructose-grown organisms in glucose restored the original proportions of the two polysaccharides. Galactose- and sucrose-grown cells behaved similarly to glucose-grown cells with respect to polysaccharide production, whereas growth in rhamnose or ribose showed values close to those for fructose-grown cells. Continuous culture of strain NCTC 6375 for more than 100 generations showed a gradual and irreversible reduction of the R-polysaccharide to less than 5% of the cell wall and an increase of the H-polysaccharide to 40% of the cell wall. Other type culture strains of L. casei subsp. rhamnosus, NCIB 7473 and ATCC 7469, behaved similarly in batch and continuous culture. In contrast, strains of L. casei subsp. rhamnosus isolated at the Institute of Dental Research showed phenotypic stability with respect to the relative proportions of R- and H-polysaccharides in both batch and continuous culture. Changes in polysaccharide composition of type culture strains were also mirrored in changes in the immunogenicity of the two components and resistance to the rate of enzymic lysis of whole organisms. For L. casei subsp. rhamnosus strain NCTC 10302 the R-polysaccharide is present entirely as capsular material. The amount of R-polysaccharide produced was also markedly dependent on the carbohydrate component of the medium in batch culture and both dilution rate and

Effect of growth conditions on production of rhamnose-containing cell wall and capsular polysaccharides by strains of Lactobacillus casei subsp. rhamnosus.

PubMed Central

Wicken, A J; Ayres, A; Campbell, L K; Knox, K W

1983-01-01

Strains of Lactobacillus casei subsp. rhamnosus possessing two cell wall polysaccharides, a hexosamine-containing H-polysaccharide and a rhamnose-containing R-polysaccharide, were examined for the effect of growth conditions on the production of these two components. In strain NCTC 6375, R- and H-polysaccharides accounted for an estimated 44 and 20%, respectively, of the cell wall for organisms grown in batch culture with glucose as the carbohydrate source. Growth on fructose-containing media reduced the amount of R-polysaccharide by approximately 50% without affecting the amount of H-polysaccharide. Subculture of fructose-grown organisms in glucose restored the original proportions of the two polysaccharides. Galactose- and sucrose-grown cells behaved similarly to glucose-grown cells with respect to polysaccharide production, whereas growth in rhamnose or ribose showed values close to those for fructose-grown cells. Continuous culture of strain NCTC 6375 for more than 100 generations showed a gradual and irreversible reduction of the R-polysaccharide to less than 5% of the cell wall and an increase of the H-polysaccharide to 40% of the cell wall. Other type culture strains of L. casei subsp. rhamnosus, NCIB 7473 and ATCC 7469, behaved similarly in batch and continuous culture. In contrast, strains of L. casei subsp. rhamnosus isolated at the Institute of Dental Research showed phenotypic stability with respect to the relative proportions of R- and H-polysaccharides in both batch and continuous culture. Changes in polysaccharide composition of type culture strains were also mirrored in changes in the immunogenicity of the two components and resistance to the rate of enzymic lysis of whole organisms. For L. casei subsp. rhamnosus strain NCTC 10302 the R-polysaccharide is present entirely as capsular material. The amount of R-polysaccharide produced was also markedly dependent on the carbohydrate component of the medium in batch culture and both dilution rate and

Fabrication and Characterization of Multi-Walled Carbon Nanotube (MWCNT) and Ni-Coated Multi-Walled Carbon Nanotube (Ni-MWCNT) Repair Patches for Carbon Fiber Reinforced Composite Systems

NASA Technical Reports Server (NTRS)

Johnson, Brienne; Caraccio, Anne; Tate, LaNetra; Jackson, Dionne

2011-01-01

Multi-walled carbon nanotube (MWCNT)/epoxy and nickel-coated multi-walled carbon nanotube (Ni-MWCNT)/epoxy systems were fabricated into carbon fiber composite repair patches via vacuum resin infusion. Two 4 ply patches were manufactured with fiber orientations of [90/ 90/ 4590] and [0/90/ +45/ -45]. Prior to resin infusion, the MWCNT/Epoxy system and NiMWCNT/ epoxy systems were optimized for dispersion quality. Scanning electron microscopy (SEM) and optical microscopy (OM) were used to determine the presence ofcarbon nanotubes and assess dispersion quality. Decomposition temperatures were determined via thermogravametric analysis (TGA). SEM and TGA were also used to evaluate the composite repair patches.

Unexpected features of exponentially growing Tobacco Bright Yellow-2 cell suspension culture in relation to excreted extracellular polysaccharides and cell wall composition.

PubMed

Issawi, Mohammad; Muhieddine, Mohammad; Girard, Celine; Sol, Vincent; Riou, Catherine

2017-10-01

This article presents a new insight about TBY-2 cells; from extracellular polysaccharides secretion to cell wall composition during cell suspension culture. In the medium of cells taken 2 days after dilution (end of lag phase), a two unit pH decrease from 5.38 to 3.45 was observed and linked to a high uronic acid (UA) amount secretion (47.8%) while, in 4 and 7 day-old spent media, pH increased and UA amounts decreased 35.6 and 42.3% UA, respectively. To attain deeper knowledge of the putative link between extracellular polysaccharide excretion and cell wall composition, we determined cell wall UA and neutral sugar composition of cells from D2 to D12 cultures. While cell walls from D2 and D3 cells contained a large amount of uronic acid (twice as much as the other analysed cell walls), similar amounts of neutral sugar were detected in cells from lag to end of exponential phase cells suggesting an enriched pectin network in young cultures. Indeed, monosaccharide composition analysis leads to an estimated percentage of pectins of 56% for D3 cell wall against 45% D7 cell walls indicating that the cells at the mid-exponential growth phase re-organized their cell wall linked to a decrease in secreted UA that finally led to a stabilization of the spent medium pH to 5.4. In conclusion, TBY-2 cell suspension from lag to stationary phase showed cell wall remodeling that could be of interest in drug interaction and internalization study.

Nickel-catalyzed proton-deuterium exchange (HDX) procedures for glycosidic linkage analysis of complex carbohydrates

USDA-ARS?s Scientific Manuscript database

The structural analysis of complex carbohydrates typically requires the assignment of three parameters: monosaccharide composition, the position of glycosidic linkages between monosaccharides, and the position and nature of non-carbohydrate substituents. The glycosidic linkage positions are often de...

Change in daily energy intake associated with pairwise compositional change in carbohydrate, fat and protein intake among US adults, 1999-2010.

PubMed

An, Ruopeng; Burd, Nicholas A

2015-06-01

To assess the change in daily energy intake associated with pairwise compositional change in carbohydrate, fat and protein intake among US adults stratified by sex, race/ethnicity and weight status. Linear mixture model was performed to estimate the relationship between daily energy intake and macronutrient composition, adjusted for age and alcohol consumption, and accounting for survey design. Study sample from the National Health and Nutrition Examination Survey, 1999-2010 waves. A total of 27 589 US adults aged 20 years and older were included in the study. Dietary macronutrient intake was calculated from 24 h dietary recall and BMI from objectively measured weight/height. Across all population subgroups, substituting protein or carbohydrate for fat and substituting protein for carbohydrate were associated with decreased daily energy intake, with the largest effect resulting from substituting protein for fat. A 1 % increase in the percentage of energy from protein substituted for a 1 % decrease in the percentage of energy from fat was associated with a decrease in daily energy intake of 268.2 (95 % CI 169.0, 367.4) kJ, 289.5 (95 % CI 215.9, 363.2) kJ and 293.7 (95 % CI 210.0, 377.4) kJ among normal-weight (18.5≤BMI, kg/m2<25.0), overweight (25.0≤BMI, kg/m2<30.0) and obese (BMI≥30.0 kg/m2) men, and 177.4 (95 % CI 130.5, 224.3) kJ, 188.7 (95 % CI 139.3, 238.1) kJ and 204.2 (95 % CI 158.2, 250.2) kJ among normal-weight, overweight and obese women, respectively. The relationship between macronutrient composition and daily energy intake varied substantially across sex, race/ethnicity and weight status. Policies promoting higher daily protein intake at the expense of lower fat intake could be effective in reducing total energy intake among US adults.

Spatially and temporally restricted expression of PtrMYB021 regulates secondary cell wall formation in Arabidopsis

DOE PAGES

Wang, Wei; Li, Eryang; Porth, Ilga; ...

2016-02-02

Among the R2R3 MYB transcription factors that involve in the regulation of secondary cell wall formation in Arabidopsis, MYB46 alone is sufficient to induce the entire secondary cell wall biosynthesis program. PtrMYB021, the poplar homolog of MYB46, has been reported to regulate secondary cell wall formation when expressed in Arabidopsis. We report here that spatially and temporally restricted expression of PtrMYB021 is critical for its function in regulating secondary cell wall formation. By using quantitative RT-PCR, we found that PtrMYB021 was expressed primarily in xylem tissues. When expressed in Arabidopsis under the control of PtrCesA8, but not the 35S promoter,more » PtrMYB021 increased secondary cell wall thickness, which is likely caused by increased lignification as well as changes in cell wall carbohydrate composition. Consistent with this, elevated expression of lignin and cellulose biosynthetic genes were observed in the transgenic plants. Finally, when expressed in Arabidopsis protoplasts as fusion proteins to the Gal4 DNA binding domain, PtrMYB021 activated the reporter gene Gal4-GUS. In summary, our results suggest that PtrMYB021 is a transcriptional activator, and spatially and temporally restricted expression of PtrMYB021 in Arabidopsis regulates secondary cell wall formation by activating a subset of secondary cell wall biosynthesis genes.« less

Spatially and temporally restricted expression of PtrMYB021 regulates secondary cell wall formation in Arabidopsis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Wei; Li, Eryang; Porth, Ilga

Among the R2R3 MYB transcription factors that involve in the regulation of secondary cell wall formation in Arabidopsis, MYB46 alone is sufficient to induce the entire secondary cell wall biosynthesis program. PtrMYB021, the poplar homolog of MYB46, has been reported to regulate secondary cell wall formation when expressed in Arabidopsis. We report here that spatially and temporally restricted expression of PtrMYB021 is critical for its function in regulating secondary cell wall formation. By using quantitative RT-PCR, we found that PtrMYB021 was expressed primarily in xylem tissues. When expressed in Arabidopsis under the control of PtrCesA8, but not the 35S promoter,more » PtrMYB021 increased secondary cell wall thickness, which is likely caused by increased lignification as well as changes in cell wall carbohydrate composition. Consistent with this, elevated expression of lignin and cellulose biosynthetic genes were observed in the transgenic plants. Finally, when expressed in Arabidopsis protoplasts as fusion proteins to the Gal4 DNA binding domain, PtrMYB021 activated the reporter gene Gal4-GUS. In summary, our results suggest that PtrMYB021 is a transcriptional activator, and spatially and temporally restricted expression of PtrMYB021 in Arabidopsis regulates secondary cell wall formation by activating a subset of secondary cell wall biosynthesis genes.« less

Lignin-carbohydrate complexes from sisal (Agave sisalana) and abaca (Musa textilis): chemical composition and structural modifications during the isolation process.

PubMed

Del Río, José C; Prinsen, Pepijn; Cadena, Edith M; Martínez, Ángel T; Gutiérrez, Ana; Rencoret, Jorge

2016-05-01

Two types of lignins occurred in different lignin-carbohydrate fractions, a lignin enriched in syringyl units, less condensed, preferentially associated with xylans, and a lignin with more guaiacyl units, more condensed, associated with glucans. Lignin-carbohydrate complexes (LCC) were isolated from the fibers of sisal (Agave sisalana) and abaca (Musa textilis) according to a plant biomass fractionation procedure recently developed and which was termed as "universally" applicable to any type of lignocellulosic material. Two LCC fractions, namely glucan-lignin (GL) and xylan-lignin (XL), were isolated and differed in the content and composition of carbohydrates and lignin. In both cases, GL fractions were enriched in glucans and comparatively depleted in lignin, whereas XL fractions were depleted in glucans, but enriched in xylans and lignin. Analysis by two-dimensional Nuclear Magnetic Resonance (2D-NMR) and Derivatization Followed by Reductive Cleavage (DFRC) indicated that the XL fractions were enriched in syringyl (S)-lignin units and β-O-4' alkyl-aryl ether linkages, whereas GL fractions have more guaiacyl (G)-lignin units and less β-O-4' alkyl-aryl ether linkages per lignin unit. The data suggest that the structural characteristics of the lignin polymers are not homogeneously distributed within the same plant and that two different lignin polymers with different composition and structure might be present. The analyses also suggested that acetates from hemicelluloses and the acyl groups (acetates and p-coumarates) attached to the γ-OH of the lignin side chains were extensively hydrolyzed and removed during the LCC fractionation process. Therefore, caution must be paid when using this fractionation approach for the structural characterization of plants with acylated hemicelluloses and lignins. Finally, several chemical linkages (phenylglycosides and benzyl ethers) could be observed to occur between lignin and xylans in these plants.

Effects of PHENYLALANINE AMMONIA LYASE ( PAL) knockdown on cell wall composition, biomass digestibility, and biotic and abiotic stress responses in Brachypodium

DOE PAGES

Cass, Cynthia L.; Peraldi, Antoine; Dowd, Patrick F.; ...

2015-06-19

The phenylpropanoid pathway in plants synthesizes a variety of structural and defence compounds, and is an important target in efforts to reduce cell wall lignin for improved biomass conversion to biofuels. Little is known concerning the trade-offs in grasses when perturbing the function of the first gene family in the pathway, PHENYLALANINE AMMONIA LYASE ( PAL). Therefore, PAL isoforms in the model grass Brachypodium distachyon were targeted, by RNA interference (RNAi), and large reductions (up to 85%) in stem tissue transcript abundance for two of the eight putative BdPAL genes were identified. The cell walls of stems of BdPAL-knockdown plantsmore » had reductions of 43% in lignin and 57% in cell wall-bound ferulate, and a nearly 2-fold increase in the amounts of polysaccharide-derived carbohydrates released by thermochemical and hydrolytic enzymic partial digestion. PAL-knockdown plants exhibited delayed development and reduced root growth, along with increased susceptibilities to the fungal pathogens Fusarium culmorum and Magnaporthe oryzae. Surprisingly, these plants generally had wild-type (WT) resistances to caterpillar herbivory, drought, and ultraviolet light. RNA sequencing analyses revealed that the expression of genes associated with stress responses including ethylene biosynthesis and signalling were significantly altered in PAL knocked-down plants under non-challenging conditions. These data reveal that, although an attenuation of the phenylpropanoid pathway increases carbohydrate availability for biofuel, it can adversely affect plant growth and disease resistance to fungal pathogens. Lastly, the data identify notable differences between the stress responses of these monocot pal mutants versus Arabidopsis (a dicot) pal mutants and provide insights into the challenges that may arise when deploying phenylpropanoid pathway-altered bioenergy crops.« less

Effects of PHENYLALANINE AMMONIA LYASE ( PAL) knockdown on cell wall composition, biomass digestibility, and biotic and abiotic stress responses in Brachypodium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cass, Cynthia L.; Peraldi, Antoine; Dowd, Patrick F.

The phenylpropanoid pathway in plants synthesizes a variety of structural and defence compounds, and is an important target in efforts to reduce cell wall lignin for improved biomass conversion to biofuels. Little is known concerning the trade-offs in grasses when perturbing the function of the first gene family in the pathway, PHENYLALANINE AMMONIA LYASE ( PAL). Therefore, PAL isoforms in the model grass Brachypodium distachyon were targeted, by RNA interference (RNAi), and large reductions (up to 85%) in stem tissue transcript abundance for two of the eight putative BdPAL genes were identified. The cell walls of stems of BdPAL-knockdown plantsmore » had reductions of 43% in lignin and 57% in cell wall-bound ferulate, and a nearly 2-fold increase in the amounts of polysaccharide-derived carbohydrates released by thermochemical and hydrolytic enzymic partial digestion. PAL-knockdown plants exhibited delayed development and reduced root growth, along with increased susceptibilities to the fungal pathogens Fusarium culmorum and Magnaporthe oryzae. Surprisingly, these plants generally had wild-type (WT) resistances to caterpillar herbivory, drought, and ultraviolet light. RNA sequencing analyses revealed that the expression of genes associated with stress responses including ethylene biosynthesis and signalling were significantly altered in PAL knocked-down plants under non-challenging conditions. These data reveal that, although an attenuation of the phenylpropanoid pathway increases carbohydrate availability for biofuel, it can adversely affect plant growth and disease resistance to fungal pathogens. Lastly, the data identify notable differences between the stress responses of these monocot pal mutants versus Arabidopsis (a dicot) pal mutants and provide insights into the challenges that may arise when deploying phenylpropanoid pathway-altered bioenergy crops.« less

In vitro evaluation of three-dimensional single-walled carbon nanotube composites for bone tissue engineering.

PubMed

Gupta, Ashim; Main, Benjamin J; Taylor, Brittany L; Gupta, Manu; Whitworth, Craig A; Cady, Craig; Freeman, Joseph W; El-Amin, Saadiq F

2014-11-01

The purpose of this study was to develop three-dimensional single-walled carbon nanotube composites (SWCNT/PLAGA) using 10-mg single-walled carbon nanotubes (SWCNT) for bone regeneration and to determine the mechanical strength of the composites, and to evaluate the interaction of MC3T3-E1 cells via cell adhesion, growth, survival, proliferation, and gene expression. PLAGA (polylactic-co-glycolic acid) and SWCNT/PLAGA microspheres and composites were fabricated, characterized, and mechanical testing was performed. MC3T3-E1 cells were seeded and cell adhesion/morphology, growth/survival, proliferation, and gene expression analysis were performed to evaluate biocompatibility. Imaging studies demonstrated microspheres with uniform shape and smooth surfaces, and uniform incorporation of SWCNT into PLAGA matrix. The microspheres bonded in a random packing manner while maintaining spacing, thus resembling trabeculae of cancellous bone. Addition of SWCNT led to greater compressive modulus and ultimate compressive strength. Imaging studies revealed that MC3T3-E1 cells adhered, grew/survived, and exhibited normal, nonstressed morphology on the composites. SWCNT/PLAGA composites exhibited higher cell proliferation rate and gene expression compared with PLAGA. These results demonstrate the potential of SWCNT/PLAGA composites for musculoskeletal regeneration, for bone tissue engineering, and are promising for orthopedic applications as they possess the combined effect of increased mechanical strength, cell proliferation, and gene expression. © 2014 Wiley Periodicals, Inc.

Weight Loss at a Cost: Implications of High-Protein, Low- Carbohydrate Diets.

ERIC Educational Resources Information Center

Gabel, Kathe A.; Lund, Robin J.

2002-01-01

Addresses three claims of high-protein, low-carbohydrate diets: weight loss is attributed to the composition of the diet; insulin promotes the storage of fat, thereby, by limiting carbohydrates, dieters will decrease levels of insulin and body fat; and weight loss is the result of fat loss. The paper examines relevant scientific reports and notes…

Abuse potential of carbohydrates for overweight carbohydrate cravers

PubMed Central

Spring, Bonnie; Schneider, Kristin; Smith, Malaina; Kendzor, Darla; Appelhans, Bradley; Hedeker, Donald; Pagoto, Sherry

2010-01-01

Rationale The long-rejected construct of food addiction is undergoing re-examination. Objectives . To evaluate whether a novel carbohydrate food shows abuse potential for rigorously defined carbohydrate cravers, as evidenced by selective self-administration and mood enhancement during double-blind discrimination testing. Methods Discrete trials choice testing was performed with 61 overweight (BMI m=27.64, SD=2.59) women (ages 18–45; 19.70% African American) whose diet records showed >4 weekly afternoon/evening emotional eating episodes confined to snacks with carbohydrate:protein ≥ 6:1. After being induced into a sad mood, participants were exposed, double-blind and in counterbalanced order, to taste-matched carbohydrate and protein beverages. They were asked to choose and self-administer the drink that made them feel better. Results Women overwhelmingly chose the carbohydrate beverage, even though blinded. Mixed-effects regression modeling, controlling for beverage order, revealed greater liking and greater reduction in dysphoria following the carbohydrate beverage compared to the protein beverage, but no differential effect on vigor. Conclusion For women who crave them, carbohydrates appear to display abuse potential, plausibly contributing to overconsumption and overweight. PMID:18273603

Understanding carbohydrate-carbohydrate interactions by means of glyconanotechnology.

PubMed

de la Fuente, Jesus M; Penadés, Soledad

2004-01-01

Carbohydrate-carbohydrate interaction is a reliable and versatile mechanism for cell adhesion and recognition. Glycosphingolipid (GSL) clusters at the cell membrane are mainly involved in this interaction. To investigate carbohydrate-carbohydrate interaction an integrated strategy (Glyconanotechnology) was developed. This strategy includes polyvalent tools (gold glyconanoparticles) mimicking GSL clustering at the cell membrane as well as analytical techniques such as AFM, TEM, and SPR to evaluate the interactions. The results obtained by means of this strategy and current status are presented.

Altering carbon allocation in hybrid poplar ( Populus alba × grandidentata ) impacts cell wall growth and development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Unda, Faride; Kim, Hoon; Hefer, Charles

Galactinol synthase is a pivotal enzyme involved in the synthesis of the raffinose family of oligosaccharides (RFOs) that function as transport carbohydrates in the phloem, as storage compounds in sink tissues and as soluble metabolites that combat both abiotic and biotic stress in several plant species. For hybrid poplar (Populus alba 9 grandidentata) overexpressing the Arabidopsis thaliana GolS3 (AtGolS3) gene showed clear effects on development; the extreme overexpressing lines were stunted and had cell wall traits characteristic of tension wood, whereas lines with only moderate up-regulation grew normally and had moderately altered secondary cell wall composition and ultrastructure. Stem cross-sectionsmore » of the developing xylem revealed a significant increase in the number of vessels, as well as the clear presence of a G-layer in the fibres. Furthermore, AtGolS3-OE lines possessed higher cellulose and lower lignin contents, an increase in cellulose crystallinity, and significantly altered hemicellulose-derived carbohydrates, notably manifested by their mannose and xylose contents. Additionally, the transgenic plants displayed elevated xylem starch content. Transcriptome interrogation of the transgenic plants showed a significant up-regulation of genes involved in the synthesis of myo-inositol, along with genes involved in sucrose degradation. Our results suggest that the over expression of GolS and its product galactinol may serve as a molecular signal that initiates metabolic changes, culminating in a change in cell wall development and potentially the formation of tension wood.« less

Altering carbon allocation in hybrid poplar ( Populus alba × grandidentata ) impacts cell wall growth and development

DOE PAGES

Unda, Faride; Kim, Hoon; Hefer, Charles; ...

2017-03-04

Galactinol synthase is a pivotal enzyme involved in the synthesis of the raffinose family of oligosaccharides (RFOs) that function as transport carbohydrates in the phloem, as storage compounds in sink tissues and as soluble metabolites that combat both abiotic and biotic stress in several plant species. For hybrid poplar (Populus alba 9 grandidentata) overexpressing the Arabidopsis thaliana GolS3 (AtGolS3) gene showed clear effects on development; the extreme overexpressing lines were stunted and had cell wall traits characteristic of tension wood, whereas lines with only moderate up-regulation grew normally and had moderately altered secondary cell wall composition and ultrastructure. Stem cross-sectionsmore » of the developing xylem revealed a significant increase in the number of vessels, as well as the clear presence of a G-layer in the fibres. Furthermore, AtGolS3-OE lines possessed higher cellulose and lower lignin contents, an increase in cellulose crystallinity, and significantly altered hemicellulose-derived carbohydrates, notably manifested by their mannose and xylose contents. Additionally, the transgenic plants displayed elevated xylem starch content. Transcriptome interrogation of the transgenic plants showed a significant up-regulation of genes involved in the synthesis of myo-inositol, along with genes involved in sucrose degradation. Our results suggest that the over expression of GolS and its product galactinol may serve as a molecular signal that initiates metabolic changes, culminating in a change in cell wall development and potentially the formation of tension wood.« less

Heat capacity changes in carbohydrates and protein-carbohydrate complexes.

PubMed

Chavelas, Eneas A; García-Hernández, Enrique

2009-05-13

Carbohydrates are crucial for living cells, playing myriads of functional roles that range from being structural or energy-storage devices to molecular labels that, through non-covalent interaction with proteins, impart exquisite selectivity in processes such as molecular trafficking and cellular recognition. The molecular bases that govern the recognition between carbohydrates and proteins have not been fully understood yet. In the present study, we have obtained a surface-area-based model for the formation heat capacity of protein-carbohydrate complexes, which includes separate terms for the contributions of the two molecular types. The carbohydrate model, which was calibrated using carbohydrate dissolution data, indicates that the heat capacity contribution of a given group surface depends on its position in the saccharide molecule, a picture that is consistent with previous experimental and theoretical studies showing that the high abundance of hydroxy groups in carbohydrates yields particular solvation properties. This model was used to estimate the carbohydrate's contribution in the formation of a protein-carbohydrate complex, which in turn was used to obtain the heat capacity change associated with the protein's binding site. The model is able to account for protein-carbohydrate complexes that cannot be explained using a previous model that only considered the overall contribution of polar and apolar groups, while allowing a more detailed dissection of the elementary contributions that give rise to the formation heat capacity effects of these adducts.

Cell Wall Chemical Composition of Enterococcus faecalis in the Viable but Nonculturable State

PubMed Central

Signoretto, Caterina; del Mar Lleò, Maria; Tafi, Maria Carla; Canepari, Pietro

2000-01-01

The viable but nonculturable (VBNC) state is a survival mechanism adopted by many bacteria (including those of medical interest) when exposed to adverse environmental conditions. In this state bacteria lose the ability to grow in bacteriological media but maintain viability and pathogenicity and sometimes are able to revert to regular division upon restoration of normal growth conditions. The aim of this work was to analyze the biochemical composition of the cell wall of Enterococcus faecalis in the VBNC state in comparison with exponentially growing and stationary cells. VBNC enterococcal cells appeared as slightly elongated and were endowed with a wall more resistant to mechanical disruption than dividing cells. Analysis of the peptidoglycan chemical composition showed an increase in total cross-linking, which rose from 39% in growing cells to 48% in VBNC cells. This increase was detected in oligomers of a higher order than dimers, such as trimers (24% increase), tetramers (37% increase), pentamers (65% increase), and higher oligomers (95% increase). Changes were also observed in penicillin binding proteins (PBPs), the enzymes involved in the terminal stages of peptidoglycan assembly, with PBPs 5 and 1 being prevalent, and in autolytic enzymes, with a threefold increase in the activity of latent muramidase-1 in E. faecalis in the VBNC state. Accessory wall polymers such as teichoic acid and lipoteichoic acid proved unchanged and doubled in quantity, respectively, in VBNC cells in comparison to dividing cells. It is suggested that all these changes in the cell wall of VBNC enterococci are specific to this particular physiological state. This may provide indirect confirmation of the viability of these cells. PMID:10788366

Comparison of four glycosyl residue composition methods for effectiveness in detecting sugars from cell walls of dicot and grass tissues.

PubMed

Biswal, Ajaya K; Tan, Li; Atmodjo, Melani A; DeMartini, Jaclyn; Gelineo-Albersheim, Ivana; Hunt, Kimberly; Black, Ian M; Mohanty, Sushree S; Ryno, David; Wyman, Charles E; Mohnen, Debra

2017-01-01

The effective use of plant biomass for biofuel and bioproduct production requires a comprehensive glycosyl residue composition analysis to understand the different cell wall polysaccharides present in the different biomass sources. Here we compared four methods side-by-side for their ability to measure the neutral and acidic sugar composition of cell walls from herbaceous, grass, and woody model plants and bioenergy feedstocks. Arabidopsis, Populus , rice, and switchgrass leaf cell walls, as well as cell walls from Populus wood, rice stems, and switchgrass tillers, were analyzed by (1) gas chromatography-mass spectrometry (GC-MS) of alditol acetates combined with a total uronic acid assay; (2) carbodiimide reduction of uronic acids followed by GC-MS of alditol acetates; (3) GC-MS of trimethylsilyl (TMS) derivatives; and (4) high-pressure, anion-exchange chromatography (HPAEC). All four methods gave comparable abundance ranking of the seven neutral sugars, and three of the methods were able to quantify unique acidic sugars. The TMS, HPAEC, and carbodiimide methods provided comparable quantitative results for the specific neutral and acidic sugar content of the biomass, with the TMS method providing slightly greater yield of specific acidic sugars and high total sugar yields. The alditol acetate method, while providing comparable information on the major neutral sugars, did not provide the requisite quantitative information on the specific acidic sugars in plant biomass. Thus, the alditol acetate method is the least informative of the four methods. This work provides a side-by-side comparison of the efficacy of four different established glycosyl residue composition analysis methods in the analysis of the glycosyl residue composition of cell walls from both dicot (Arabidopsis and Populus ) and grass (rice and switchgrass) species. Both primary wall-enriched leaf tissues and secondary wall-enriched wood/stem tissues were analyzed for mol% and mass yield of the non

Leaf carbohydrate metabolism during defense

PubMed Central

Essmann, Jutta; Bones, Philipp; Weis, Engelbert

2008-01-01

The significance of cell wall invertase (cwINV) for plant defense was investigated by comparing wild type (wt) tobacco Nicotiana tabacum L. Samsun NN (SNN) with plants with RNA interference-mediated repression of cwINV (SNN::cwINV) during the interaction with the oomycetic phytopathogen Phytophthora nicotianae. We have previously shown that the transgenic plants developed normally under standard growth conditions, but exhibited weaker defense reactions in infected source leaves and were less tolerant to the pathogen. Here, we show that repression of cwINV was not accompanied by any compensatory activities of intracellular sucrose-cleaving enzymes such as vacuolar and alkaline/neutral invertases or sucrose synthase (SUSY), neither in uninfected controls nor during infection. In wt source leaves vacuolar invertase did not respond to infection, and the activity of alkaline/neutral invertases increased only slightly. SUSY however, was distinctly stimulated, in parallel to enhanced cwINV. In SNN::cwINV SUSY-activation was largely repressed upon infection. SUSY may serve to allocate sucrose into callose deposition and other carbohydrate-consuming defense reactions. Its activity, however, seems to be directly affected by cwINV and the related reflux of carbohydrates from the apoplast into the mesophyll cells. PMID:19704530

Strengthening behavior of chopped multi-walled carbon nanotube reinforced aluminum matrix composites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shin, S.E.; Bae, D.H., E-mail: donghyun@yonsei.ac.kr

2013-09-15

Strengthening behavior of the aluminum composites reinforced with chopped multi-walled carbon nanotubes (MWCNTs) or aluminum carbide formed during annealing at 500 °C has been investigated. The composites were fabricated by hot-rolling the powders which were ball-milled under various conditions. During the early annealing process, aluminum atoms can cluster inside the tube due to the diffusional flow of aluminum atoms into the tube, providing an increase of the strength of the composite. Further annealing induces the formation of the aluminum carbide phase, leading to an overall drop in the strength of the composites. While the strength of the composites can bemore » evaluated according to the rule of mixture, a particle spacing effect can be additionally imparted on the strength of the composites reinforced with the chopped MWCNTs or the corresponding carbides since the reinforcing agents are smaller than the submicron matrix grains. - Highlights: • Strengthening behavior of chopped CNT reinforced Al-based composites is investigated. • Chopped CNTs have influenced the strength and microstructures of the composites. • Chopped CNTs are created under Ar- 3% H2 atmosphere during mechanical milling. • Strength can be evaluated by the rule of the mixture and a particle spacing effect.« less

Carbohydrates

MedlinePlus

... include sugars added during food processing and refining. Complex carbohydrates include whole grain breads and cereals, starchy vegetables and legumes. Many of the complex carbohydrates are good sources of fiber. For a healthy ...

Genetic complexity of miscanthus cell wall composition and biomass quality for biofuels.

PubMed

van der Weijde, Tim; Kamei, Claire L Alvim; Severing, Edouard I; Torres, Andres F; Gomez, Leonardo D; Dolstra, Oene; Maliepaard, Chris A; McQueen-Mason, Simon J; Visser, Richard G F; Trindade, Luisa M

2017-05-25

Miscanthus sinensis is a high yielding perennial grass species with great potential as a bioenergy feedstock. One of the challenges that currently impedes commercial cellulosic biofuel production is the technical difficulty to efficiently convert lignocellulosic biomass into biofuel. The development of feedstocks with better biomass quality will improve conversion efficiency and the sustainability of the value-chain. Progress in the genetic improvement of biomass quality may be substantially expedited by the development of genetic markers associated to quality traits, which can be used in a marker-assisted selection program. To this end, a mapping population was developed by crossing two parents of contrasting cell wall composition. The performance of 182 F1 offspring individuals along with the parents was evaluated in a field trial with a randomized block design with three replicates. Plants were phenotyped for cell wall composition and conversion efficiency characters in the second and third growth season after establishment. A new SNP-based genetic map for M. sinensis was built using a genotyping-by-sequencing (GBS) approach, which resulted in 464 short-sequence uniparental markers that formed 16 linkage groups in the male map and 17 linkage groups in the female map. A total of 86 QTLs for a variety of biomass quality characteristics were identified, 20 of which were detected in both growth seasons. Twenty QTLs were directly associated to different conversion efficiency characters. Marker sequences were aligned to the sorghum reference genome to facilitate cross-species comparisons. Analyses revealed that for some traits previously identified QTLs in sorghum occurred in homologous regions on the same chromosome. In this work we report for the first time the genetic mapping of cell wall composition and bioconversion traits in the bioenergy crop miscanthus. These results are a first step towards the development of marker-assisted selection programs in miscanthus

Biologically-Inspired Peptide Reagents for Enhancing IMS-MS Analysis of Carbohydrates

NASA Astrophysics Data System (ADS)

Bohrer, Brian C.; Clemmer, David E.

2011-09-01

The binding properties of a peptidoglycan recognition protein are translated via combinatorial chemistry into short peptides. Non-adjacent histidine, tyrosine, and arginine residues in the protein's binding cleft that associate specifically with the glycan moiety of a peptidoglycan substrate are incorporated into linear sequences creating a library of 27 candidate tripeptide reagents (three possible residues permutated across three positions). Upon electrospraying the peptide library and carbohydrate mixtures, some noncovalent complexes are observed. The binding efficiencies of the peptides vary according to their amino acid composition as well as the disaccharide linkage and carbohydrate ring-type. In addition to providing a charge-carrier for the carbohydrate, peptide reagents can also be used to differentiate carbohydrate isomers by ion mobility spectrometry. The utility of these peptide reagents as a means of enhancing ion mobility analysis of carbohydrates is illustrated by examining four glucose-containing disaccharide isomers, including a pair that is not resolved by ion mobility alone. The specificity and stoichiometry of the peptide-carbohydrate complexes are also investigated. Trihistidine demonstrates both suitable binding efficiency and successful resolution of disaccharides isomers, suggesting it may be a useful reagent in IMS analyses of carbohydrates.

Linear strain sensor made of multi-walled carbon nanotube/epoxy composite

NASA Astrophysics Data System (ADS)

Tong, Shuying; Yuan, Weifeng; Liu, Haidong; Alamusi; Hu, Ning; Zhao, Chaoyang; Zhao, Yangzhou

2017-11-01

In this study, a fabrication process was developed to make the multi-walled carbon nanotubes/epoxy (MWCNT/EP) composite films. The electrical-strain behaviour of the films in direct and alternating current circuits were both tested. It is found that the direct current resistance and the dielectric loss tangent of the MWCNT/EP composite films are dependent on the strain and the weight fraction of the carbon nanotubes. In an alternating current circuit, the test frequency affects the impedance and the phase angle of the composite film, but it has nothing to do with the change ratio of the dielectric loss tangent of the film in tension. This phenomenon can be interpreted by a proposed equivalent circuit model. Experiment results show that the change rate of the dielectric loss tangent of the MWCNT/EP sensor is linearly proportional to the strain. The findings obtained in the present study provide a promising method to develop ultrasensitive linear strain gauges.

The growing outer epidermal wall: design and physiological role of a composite structure.

PubMed

Kutschera, U

2008-04-01

The cells of growing plant organs secrete an extracellular fibrous composite (the primary wall) that allows the turgid protoplasts to expand irreversibly via wall-yielding events, which are regulated by processes within the cytoplasm. The role of the epidermis in the control of stem elongation is described with special reference to the outer epidermal wall (OEW), which forms a 'tensile skin'. The OEW is much thicker and less extensible than the walls of the inner tissues. Moreover, in the OEW the amount of cellulose per unit wall mass is considerably greater than in the inner tissues. Ultrastructural studies have shown that the expanding OEW is composed of a highly ordered internal and a diffuse outer half, with helicoidally organized cellulose microfibrils in the inner (load-bearing) region of this tension-stressed organ wall. The structural and mechanical backbone of the wall consists of helicoids, i.e. layers of parallel, inextensible cellulose microfibrils. These 'plywood laminates' contain crystalline 'cables' orientated in all directions with respect to the axis of elongation (isotropic material). Cessation of cell elongation is accompanied by a loss of order, i.e. the OEW is a dynamic structure. Helicoidally arranged extracellular polymers have also been found in certain bacteria, algae, fungi and animals. In the insect cuticle crystalline cutin nanofibrils form characteristic 'OEW-like' herringbone patterns. Theoretical considerations, in vitro studies and computer simulations suggest that extracellular biological helicoids form by directed self-assembly of the crystalline biopolymers. This spontaneous generation of complex design 'without an intelligent designer' evolved independently in the protective 'skin' of plants, animals and many other organisms.

Effects of freezing and thawing on texture, microstructure and cell wall composition changes in papaya tissues.

PubMed

Phothiset, Suphatta; Charoenrein, Sanguansri

2014-01-30

During storage, frozen fruit may be thawed and refrozen many times before consumption, which may be extremely damaging to the texture of the frozen fruit and reverse the advantage of fast freezing. The effects of freezing and thawing on texture, microstructure and cell wall composition changes in papaya tissues were investigated. The frozen-thawed papayas had an increase in drip loss and a decrease in firmness with increasing number of freeze-thaw cycles. Light microscopy showed irregular shapes and cell damage in parenchyma cells of frozen-thawed papayas, whereas transmission electron microscopy showed loss of cell wall materials in middle lamella. Moreover, destruction of cell wall was observed after being subjected to five freeze-thaw cycles. These changes related with a significant decrease in alcohol-insoluble solids, Na₂CO₃- and 24% KOH-soluble fractions and an increase in the water-, EDTA- and 4% KOH-soluble fractions. This was due to a decrease in the molecular mass of pectic and hemicellulosic polymers in frozen-thawed papayas using high-performance size-exclusion chromatography. The freezing and thawing processes caused fine structural damage and cell wall composition changes which contributed to a loss of drip volume and firmness of papaya tissues. © 2013 Society of Chemical Industry.

Measurement of the distribution of non-structural carbohydrate composition in onion populations by a high-throughput microplate enzymatic assay.

PubMed

Revanna, Roopashree; Turnbull, Matthew H; Shaw, Martin L; Wright, Kathryn M; Butler, Ruth C; Jameson, Paula E; McCallum, John A

2013-08-15

Non-structural carbohydrate (NSC; glucose, fructose, sucrose and fructan) composition of onions (Allium cepa L.) varies widely and is a key determinant of market usage. To analyse the physiology and genetics of onion carbohydrate metabolism and to enable selective breeding, an inexpensive, reliable and practicable sugar assay is required to phenotype large numbers of samples. A rapid, reliable and cost-effective microplate-based assay was developed for NSC analysis in onions and used to characterise variation in tissue hexose, sucrose and fructan content in open-pollinated breeding populations and in mapping populations developed from a wide onion cross. Sucrose measured in microplates employing maltase as a hydrolytic enzyme was in agreement with HPLC-PAD results. The method revealed significant variation in bulb fructan content within open-pollinated 'Pukekohe Longkeeper' breeding populations over a threefold range. Very wide segregation from 80 to 600 g kg(-1) in fructan content was observed in bulbs of F2 genetic mapping populations from the wide onion cross 'Nasik Red × CUDH2150'. The microplate enzymatic assay is a reliable and practicable method for onion sugar analysis for genetics, breeding and food technology. Open-pollinated onion populations may harbour extensive within-population variability in carbohydrate content, which may be quantified and exploited using this method. The phenotypic data obtained from genetic mapping populations show that the method is well suited to detailed genetic and physiological analysis. © 2013 Society of Chemical Industry.

Carbohydrate Analysis

NASA Astrophysics Data System (ADS)

Bemiller, James N.

Carbohydrates are important in foods as a major source of energy, to impart crucial textural properties, and as dietary fiber which influences physiological processes. Digestible carbohydrates, which are converted into monosaccharides, which are absorbed, provide metabolic energy. Worldwide, carbohydrates account for more than 70% of the caloric value of the human diet. It is recommended that all persons should limit calories from fat (the other significant source) to not more than 30% and that most of the carbohydrate calories should come from starch. Nondigestible polysaccharides (all those other than starch) comprise the major portion of dietary fiber (Sect. 10.5). Carbohydrates also contribute other attributes, including bulk, body, viscosity, stability to emulsions and foams, water-holding capacity, freeze-thaw stability, browning, flavors, aromas, and a range of desirable textures (from crispness to smooth, soft gels). They also provide satiety. Basic carbohydrate structures, chemistry, and terminology can be found in references (1, 2).

Using isolated cell wall xylan to identify recalcitrant oligosaccharides

USDA-ARS?s Scientific Manuscript database

Herbaceous biomass is a renewable source of carbohydrates with potential for use in microbial conversion to biofuels. Xylan comprises 20-40% of herbaceous biomass cell wall material and its full depolymerization benefits the economics of bioconversion. To understand the limitations of commercial enz...

Recalcitrant carbohydrates after enzymatic hydrolysis of pretreated lignocellulosic biomass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alcantara, Maria Angeles Bermudez; Dobruchowska, Justyna; Azadi, Parastoo

To reduce the cost of the enzymes for the hydrolysis of lignocellulosic biomass, two main strategies have been followed: one, the reduction of enzyme dosing by the use of more efficient and stable enzymatic cocktails; another, to include accessory enzymes in the cocktails to increase yields by reducing the recalcitrant carbohydrate fraction remaining at the end of the process. To guide this second strategy, we have explored the chemical bond composition of different fractions of recalcitrant carbohydrates after enzymatic hydrolysis. As a result, two lignocellulosic feedstocks of relevance for the biofuels industry have been analyzed, corn stover and sugarcane straw.more » On comparing the composition of chemical bonds of the starting pretreated material with samples after standard and forced hydrolysis (with enzyme overdosing), we obtained similar sugar and chemical bond composition. In conclusion, this suggests that the current enzymatic cocktails bear the set of enzymes needed to hydrolyze these feedstocks. From our point of view, the results show the need for a parallel fine-tuning of the enzymatic cocktails with the pretreatment process to maximize sugar release yield.« less

Recalcitrant carbohydrates after enzymatic hydrolysis of pretreated lignocellulosic biomass

DOE PAGES

Alcantara, Maria Angeles Bermudez; Dobruchowska, Justyna; Azadi, Parastoo; ...

2016-10-06

To reduce the cost of the enzymes for the hydrolysis of lignocellulosic biomass, two main strategies have been followed: one, the reduction of enzyme dosing by the use of more efficient and stable enzymatic cocktails; another, to include accessory enzymes in the cocktails to increase yields by reducing the recalcitrant carbohydrate fraction remaining at the end of the process. To guide this second strategy, we have explored the chemical bond composition of different fractions of recalcitrant carbohydrates after enzymatic hydrolysis. As a result, two lignocellulosic feedstocks of relevance for the biofuels industry have been analyzed, corn stover and sugarcane straw.more » On comparing the composition of chemical bonds of the starting pretreated material with samples after standard and forced hydrolysis (with enzyme overdosing), we obtained similar sugar and chemical bond composition. In conclusion, this suggests that the current enzymatic cocktails bear the set of enzymes needed to hydrolyze these feedstocks. From our point of view, the results show the need for a parallel fine-tuning of the enzymatic cocktails with the pretreatment process to maximize sugar release yield.« less

Recalcitrant carbohydrates after enzymatic hydrolysis of pretreated lignocellulosic biomass.

PubMed

Alcántara, María Ángeles Bermúdez; Dobruchowska, Justyna; Azadi, Parastoo; García, Bruno Díez; Molina-Heredia, Fernando P; Reyes-Sosa, Francisco Manuel

2016-01-01

To reduce the cost of the enzymes for the hydrolysis of lignocellulosic biomass, two main strategies have been followed: one, the reduction of enzyme dosing by the use of more efficient and stable enzymatic cocktails; another, to include accessory enzymes in the cocktails to increase yields by reducing the recalcitrant carbohydrate fraction remaining at the end of the process. To guide this second strategy, we have explored the chemical bond composition of different fractions of recalcitrant carbohydrates after enzymatic hydrolysis. Two lignocellulosic feedstocks of relevance for the biofuels industry have been analyzed, corn stover and sugarcane straw. On comparing the composition of chemical bonds of the starting pretreated material with samples after standard and forced hydrolysis (with enzyme overdosing), we obtained similar sugar and chemical bond composition. This suggests that the current enzymatic cocktails bear the set of enzymes needed to hydrolyze these feedstocks. From our point of view, the results show the need for a parallel fine-tuning of the enzymatic cocktails with the pretreatment process to maximize sugar release yield.

Plant cell walls throughout evolution: towards a molecular understanding of their design principles.

PubMed

Sarkar, Purbasha; Bosneaga, Elena; Auer, Manfred

2009-01-01

Throughout their life, plants typically remain in one location utilizing sunlight for the synthesis of carbohydrates, which serve as their sole source of energy as well as building blocks of a protective extracellular matrix, called the cell wall. During the course of evolution, plants have repeatedly adapted to their respective niche, which is reflected in the changes of their body plan and the specific design of cell walls. Cell walls not only changed throughout evolution but also are constantly remodelled and reconstructed during the development of an individual plant, and in response to environmental stress or pathogen attacks. Carbohydrate-rich cell walls display complex designs, which together with the presence of phenolic polymers constitutes a barrier for microbes, fungi, and animals. Throughout evolution microbes have co-evolved strategies for efficient breakdown of cell walls. Our current understanding of cell walls and their evolutionary changes are limited as our knowledge is mainly derived from biochemical and genetic studies, complemented by a few targeted yet very informative imaging studies. Comprehensive plant cell wall models will aid in the re-design of plant cell walls for the purpose of commercially viable lignocellulosic biofuel production as well as for the timber, textile, and paper industries. Such knowledge will also be of great interest in the context of agriculture and to plant biologists in general. It is expected that detailed plant cell wall models will require integrated correlative multimodal, multiscale imaging and modelling approaches, which are currently underway.

The Complex Cell Wall Composition of Syncytia Induced by Plant Parasitic Cyst Nematodes Reflects Both Function and Host Plant.

PubMed

Zhang, Li; Lilley, Catherine J; Imren, Mustafa; Knox, J Paul; Urwin, Peter E

2017-01-01

Plant-parasitic cyst nematodes induce the formation of specialized feeding structures, syncytia, within their host roots. These unique plant organs serve as the sole nutrient resource for development and reproduction throughout the biotrophic interaction. The multinucleate syncytium, which arises through local dissolution of cell walls and protoplast fusion of multiple adjacent cells, has dense cytoplasm containing numerous organelles, surrounded by thickened outer cell walls that must withstand high turgor pressure. However, little is known about how the constituents of the syncytial cell wall and their conformation support its role during nematode parasitism. We used a set of monoclonal antibodies, targeted to a range of plant cell wall components, to reveal the microstructures of syncytial cell walls induced by four of the most economically important cyst nematode species, Globodera pallida , Heterodera glycines , Heterodera avenae and Heterodera filipjevi , in their respective potato, soybean, and spring wheat host roots. In situ fluorescence analysis revealed highly similar cell wall composition of syncytia induced by G. pallida and H. glycines . Both consisted of abundant xyloglucan, methyl-esterified homogalacturonan and pectic arabinan. In contrast, the walls of syncytia induced in wheat roots by H. avenae and H. filipjevi contain little xyloglucan but are rich in feruloylated xylan and arabinan residues, with variable levels of mixed-linkage glucan. The overall chemical composition of syncytial cell walls reflected the general features of root cell walls of the different host plants. We relate specific components of syncytial cell walls, such as abundant arabinan, methyl-esterification status of pectic homogalacturonan and feruloylation of xylan, to their potential roles in forming a network to support both the strength and flexibility required for syncytium function.

The Complex Cell Wall Composition of Syncytia Induced by Plant Parasitic Cyst Nematodes Reflects Both Function and Host Plant

PubMed Central

Zhang, Li; Lilley, Catherine J.; Imren, Mustafa; Knox, J. Paul; Urwin, Peter E.

2017-01-01

Plant–parasitic cyst nematodes induce the formation of specialized feeding structures, syncytia, within their host roots. These unique plant organs serve as the sole nutrient resource for development and reproduction throughout the biotrophic interaction. The multinucleate syncytium, which arises through local dissolution of cell walls and protoplast fusion of multiple adjacent cells, has dense cytoplasm containing numerous organelles, surrounded by thickened outer cell walls that must withstand high turgor pressure. However, little is known about how the constituents of the syncytial cell wall and their conformation support its role during nematode parasitism. We used a set of monoclonal antibodies, targeted to a range of plant cell wall components, to reveal the microstructures of syncytial cell walls induced by four of the most economically important cyst nematode species, Globodera pallida, Heterodera glycines, Heterodera avenae and Heterodera filipjevi, in their respective potato, soybean, and spring wheat host roots. In situ fluorescence analysis revealed highly similar cell wall composition of syncytia induced by G. pallida and H. glycines. Both consisted of abundant xyloglucan, methyl-esterified homogalacturonan and pectic arabinan. In contrast, the walls of syncytia induced in wheat roots by H. avenae and H. filipjevi contain little xyloglucan but are rich in feruloylated xylan and arabinan residues, with variable levels of mixed-linkage glucan. The overall chemical composition of syncytial cell walls reflected the general features of root cell walls of the different host plants. We relate specific components of syncytial cell walls, such as abundant arabinan, methyl-esterification status of pectic homogalacturonan and feruloylation of xylan, to their potential roles in forming a network to support both the strength and flexibility required for syncytium function. PMID:28680436

Cell Wall Composition and Underlying QTL in an F1 Pseudo-Testcross Population of Switchgrass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Serba, Desalegn D.; Sykes, Robert W.; Gjersing, Erica L.

Natural genetic variation for reduced recalcitrance can be used to improve switchgrass for biofuel production. A full-sib switchgrass mapping population developed by crossing a lowland genotype, AP13, and upland genotype, VS16, was evaluated at three locations (Ardmore and Burneyville, OK and Watkinsville, GA). Biomass harvested after senescence in 2009 and 2010 was evaluated at the National Renewable Energy Laboratory (NREL) for sugar release using enzymatic hydrolysis and for lignin content and syringyl/guaiacyl lignin monomer (S/G) ratio using pyrolysis molecular beam mass spectrometry (py-MBMS). Glucose and xylose release ranged from 120 to 313 and 123 to 263 mg g -1, respectively,more » while lignin content ranged from 19 to 27% of the dry biomass. Statistically significant differences were observed among the genotypes and the environments for the cell wall composition traits. Regression analysis showed that a unit increase in lignin content reduced total sugar release by an average of 10 mg g -1. Quantitative trait loci (QTL) analysis detected 9 genomic regions underlying sugar release and 14 for lignin content. The phenotypic variation explained by the individual QTL identified for sugar release ranged from 4.5 to 9.4 and for lignin content from 3.8 to 11.1%. Mapping of the QTL regions to the switchgrass genome sequence (v1.1) found that some of the QTL colocalized with genes involved in carbohydrate processing and metabolism, plant development, defense systems, and transcription factors. Finally, the markers associated with QTL can be implemented in breeding programs to efficiently develop improved switchgrass cultivars for biofuel production.« less

Cell Wall Composition and Underlying QTL in an F1 Pseudo-Testcross Population of Switchgrass

DOE PAGES

Serba, Desalegn D.; Sykes, Robert W.; Gjersing, Erica L.; ...

2016-04-23

Natural genetic variation for reduced recalcitrance can be used to improve switchgrass for biofuel production. A full-sib switchgrass mapping population developed by crossing a lowland genotype, AP13, and upland genotype, VS16, was evaluated at three locations (Ardmore and Burneyville, OK and Watkinsville, GA). Biomass harvested after senescence in 2009 and 2010 was evaluated at the National Renewable Energy Laboratory (NREL) for sugar release using enzymatic hydrolysis and for lignin content and syringyl/guaiacyl lignin monomer (S/G) ratio using pyrolysis molecular beam mass spectrometry (py-MBMS). Glucose and xylose release ranged from 120 to 313 and 123 to 263 mg g -1, respectively,more » while lignin content ranged from 19 to 27% of the dry biomass. Statistically significant differences were observed among the genotypes and the environments for the cell wall composition traits. Regression analysis showed that a unit increase in lignin content reduced total sugar release by an average of 10 mg g -1. Quantitative trait loci (QTL) analysis detected 9 genomic regions underlying sugar release and 14 for lignin content. The phenotypic variation explained by the individual QTL identified for sugar release ranged from 4.5 to 9.4 and for lignin content from 3.8 to 11.1%. Mapping of the QTL regions to the switchgrass genome sequence (v1.1) found that some of the QTL colocalized with genes involved in carbohydrate processing and metabolism, plant development, defense systems, and transcription factors. Finally, the markers associated with QTL can be implemented in breeding programs to efficiently develop improved switchgrass cultivars for biofuel production.« less

Carbohydrates.

PubMed

Cocinero, Emilio J; Çarçabal, Pierre

2015-01-01

Although carbohydrates represent one of the most important families of biomolecules, they remain under-studied in comparison to the other biomolecular families (peptides, nucleobases). Beyond their best-known function of energy source in living systems, they act as mediator of molecular recognition processes, carrying molecular information in the so-called "sugar code," just to name one of their countless functions. Owing to their high conformational flexibility, they encode extremely rich information conveyed via the non-covalent hydrogen bonds within the carbohydrate and with other biomolecular assemblies, such as peptide subunits of proteins. Over the last decade there has been tremendous progress in the study of the conformational preferences of neutral oligosaccharides, and of the interactions between carbohydrates and various molecular partners (water, aromatic models, and peptide models), using vibrational spectroscopy as a sensitive probe. In parallel, other spectroscopic techniques have recently become available to the study of carbohydrates in the gas phase (microwave spectroscopy, IRMPD on charged species).

Genetic and environmental factors contribute to variation in cell wall composition in mature desi chickpea (Cicer arietinum L.) cotyledons.

PubMed

Wood, Jennifer A; Tan, Hwei-Ting; Collins, Helen M; Yap, Kuok; Khor, Shi Fang; Lim, Wai Li; Xing, Xiaohui; Bulone, Vincent; Burton, Rachel A; Fincher, Geoffrey B; Tucker, Matthew R

2018-03-13

Chickpea (Cicer arietinum L.) is an important nutritionally rich legume crop that is consumed worldwide. Prior to cooking, desi chickpea seeds are most often dehulled and cleaved to release the split cotyledons, referred to as dhal. Compositional variation between desi genotypes has a significant impact on nutritional quality and downstream processing, and this has been investigated mainly in terms of starch and protein content. Studies in pulses such as bean and lupin have also implicated cell wall polysaccharides in cooking time variation, but the underlying relationship between desi chickpea cotyledon composition and cooking performance remains unclear. Here, we utilized a variety of chemical and immunohistological assays to examine details of polysaccharide composition, structure, abundance, and location within the desi chickpea cotyledon. Pectic polysaccharides were the most abundant cell wall components, and differences in monosaccharide and glycosidic linkage content suggest both environmental and genetic factors contribute to cotyledon composition. Genotype-specific differences were identified in arabinan structure, pectin methylesterification, and calcium-mediated pectin dimerization. These differences were replicated in distinct field sites and suggest a potentially important role for cell wall polysaccharides and their underlying regulatory machinery in the control of cooking time in chickpea. © 2018 The Authors. Plant, Cell & Environment Published by John Wiley & Sons Ltd.

Parasite Carbohydrate Vaccines.

PubMed

Jaurigue, Jonnel A; Seeberger, Peter H

2017-01-01

Vaccination is an efficient means of combating infectious disease burden globally. However, routine vaccines for the world's major human parasitic diseases do not yet exist. Vaccines based on carbohydrate antigens are a viable option for parasite vaccine development, given the proven success of carbohydrate vaccines to combat bacterial infections. We will review the key components of carbohydrate vaccines that have remained largely consistent since their inception, and the success of bacterial carbohydrate vaccines. We will then explore the latest developments for both traditional and non-traditional carbohydrate vaccine approaches for three of the world's major protozoan parasitic diseases-malaria, toxoplasmosis, and leishmaniasis. The traditional prophylactic carbohydrate vaccine strategy is being explored for malaria. However, given that parasite disease biology is complex and often arises from host immune responses to parasite antigens, carbohydrate vaccines against deleterious immune responses in host-parasite interactions are also being explored. In particular, the highly abundant glycosylphosphatidylinositol molecules specific for Plasmodium, Toxoplasma , and Leishmania spp. are considered exploitable antigens for this non-traditional vaccine approach. Discussion will revolve around the application of these protozoan carbohydrate antigens for vaccines currently in preclinical development.

Parasite Carbohydrate Vaccines

PubMed Central

Jaurigue, Jonnel A.; Seeberger, Peter H.

2017-01-01

Vaccination is an efficient means of combating infectious disease burden globally. However, routine vaccines for the world's major human parasitic diseases do not yet exist. Vaccines based on carbohydrate antigens are a viable option for parasite vaccine development, given the proven success of carbohydrate vaccines to combat bacterial infections. We will review the key components of carbohydrate vaccines that have remained largely consistent since their inception, and the success of bacterial carbohydrate vaccines. We will then explore the latest developments for both traditional and non-traditional carbohydrate vaccine approaches for three of the world's major protozoan parasitic diseases—malaria, toxoplasmosis, and leishmaniasis. The traditional prophylactic carbohydrate vaccine strategy is being explored for malaria. However, given that parasite disease biology is complex and often arises from host immune responses to parasite antigens, carbohydrate vaccines against deleterious immune responses in host-parasite interactions are also being explored. In particular, the highly abundant glycosylphosphatidylinositol molecules specific for Plasmodium, Toxoplasma, and Leishmania spp. are considered exploitable antigens for this non-traditional vaccine approach. Discussion will revolve around the application of these protozoan carbohydrate antigens for vaccines currently in preclinical development. PMID:28660174

Function and dynamics of auxin and carbohydrates during earlywood/latewood transition in scots pine.

PubMed

Uggla, C; Magel, E; Moritz, T; Sundberg, B

2001-04-01

In temperate regions the annual pattern of wood development is characterized by the formation of radially narrow and thick walled latewood cells. This takes place at the later part of the growing season when cambial cell division declines. To gain new insight into the regulation of this process, micro-analytical techniques were used to visualize the distribution of indole-3-acetic acid (IAA), soluble carbohydrates, and activities of sucrose (Suc)-metabolizing enzymes across the cambial region tissues in Scots pine (Pinus sylvestris). The total amount of IAA in the cambial region did not change with latewood initiation. But its radial distribution pattern was altered, resulting in an increased concentration in the cambial meristem and its recent derivatives. Thus, initiation of latewood formation and cessation of cambial cell division is not a consequence of decreased IAA concentrations in dividing and expanding cells. Rather, IAA most likely has a role in defining the altered developmental pattern associated with latewood formation. Carbohydrates and enzyme activities showed distinctive radial distribution patterns. Suc peaked in the phloem and decreased sharply to low levels across the cambial zone, whereas fructose and glucose reached their highest levels in the maturing tracheids. Suc synthase was the dominating Suc cleaving enzyme with a peak in the secondary wall-forming tracheids and in the phloem. Soluble acid invertase peaked in dividing and expanding cells. Suc-phosphate synthase had its highest activities in the phloem. Activities of cell wall bound invertase were low. The absence of major seasonal variations indicates that carbohydrate availability is not a trigger for latewood initiation. However, steep concentration gradients of the sugars suggest a role for sugar signaling in vascular development.

Fabrication of single/multi-walled hybrid buckypaper composites and their enhancement of electromagnetic interference shielding performance

NASA Astrophysics Data System (ADS)

Lu, Shaowei; Shao, Junyan; Ma, Keming; Wang, Xiaoqiang; Zhang, Lu; Meng, Qingshi

2016-11-01

Multi-walled carbon nanotubes and single-walled carbon nanotubes show great potential for the application as an electromagnetic interference shielding material. In this paper, the electromagnetic interference shielding the effectiveness of a composite surface coated single/multi-walled carbon nanotube hybrid buckypaper was measured, which showed an average shielding effectiveness of ~55 dB with a buckypaper thickness of 50 µm, and bukypaper density of 0.76 g cm-3, it is much higher than other carbon nanotube/resin materials when sample thickness is on the similar order. The structural, specific surface area and conductivity of the buckypapers were examined by field-emission scanning electron microscopy, specific surface area analyzer and four probes resistance tester, respectively.

Adherence to low-carbohydrate and low-fat diets in relation to weight loss and cardiovascular risk factors.

PubMed

Hu, Tian; Yao, Lu; Reynolds, Kristi; Niu, Tianhua; Li, Shengxu; Whelton, Paul K; He, Jiang; Steffen, Lyn M; Bazzano, Lydia A

2016-03-01

A low-carbohydrate diet can reduce body weight and some cardiovascular disease (CVD) risk factors more than a low-fat diet, but differential adherence may play a role in these effects. Data were used from 148 adults who participated in a 12-month clinical trial examining the effect of a low-carbohydrate diet (<40 g/day) and a low-fat diet (<30% fat, <7% saturated fat) on weight and CVD risk factors. We compared attendance at counseling sessions, deviation from nutrient goals, urinary ketone presence, and composite scores representing the overall adherence based on the distribution of these individual indicators between two interventions. Composite scores were similar between the two groups. A one-interquartile-range increase in composite score representing better adherence to a low-carbohydrate diet was associated with 2.2 kg or 2.3 % greater weight loss, 1.1 greater reduction in percent fat mass, and 1.3 greater increase in proportion of lean mass. Indicators of adherence to a low-fat diet was not associated with changes in weight, fat mass or lean mass. Despite comparable adherence between groups, a low-carbohydrate diet was associated with greater reductions in body weight and improvement in body composition, while a low-fat diet was not associated with weight loss.

Low-Fat Versus Low-Carbohydrate Weight Reduction Diets

PubMed Central

Bradley, Una; Spence, Michelle; Courtney, C. Hamish; McKinley, Michelle C.; Ennis, Cieran N.; McCance, David R.; McEneny, Jane; Bell, Patrick M.; Young, Ian S.; Hunter, Steven J.

2009-01-01

OBJECTIVE Low-fat hypocaloric diets reduce insulin resistance and prevent type 2 diabetes in those at risk. Low-carbohydrate, high-fat diets are advocated as an alternative, but reciprocal increases in dietary fat may have detrimental effects on insulin resistance and offset the benefits of weight reduction. RESEARCH DESIGN AND METHODS We investigated a low-fat (20% fat, 60% carbohydrate) versus a low-carbohydrate (60% fat, 20% carbohydrate) weight reduction diet in 24 overweight/obese subjects ([mean ± SD] BMI 33.6 ± 3.7 kg/m2, aged 39 ± 10 years) in an 8-week randomized controlled trial. All food was weighed and distributed, and intake was calculated to produce a 500 kcal/day energy deficit. Insulin action was assessed by the euglycemic clamp and insulin secretion by meal tolerance test. Body composition, adipokine levels, and vascular compliance by pulse-wave analysis were also measured. RESULTS Significant weight loss occurred in both groups (P < 0.01), with no difference between groups (P = 0.40). Peripheral glucose uptake increased, but there was no difference between groups (P = 0.28), and suppression of endogenous glucose production was also similar between groups. Meal tolerance–related insulin secretion decreased with weight loss with no difference between groups (P = 0.71). The change in overall systemic arterial stiffness was, however, significantly different between diets (P = 0.04); this reflected a significant decrease in augmentation index following the low-fat diet, compared with a nonsignificant increase within the low-carbohydrate group. CONCLUSIONS This study demonstrates comparable effects on insulin resistance of low-fat and low-carbohydrate diets independent of macronutrient content. The difference in augmentation index may imply a negative effect of low-carbohydrate diets on vascular risk. PMID:19720791

Effective permittivity of single-walled carbon nanotube composites: Two-fluid model

NASA Astrophysics Data System (ADS)

Moradi, Afshin; Zangeneh, Hamid Reza; Moghadam, Firoozeh Karimi

2015-12-01

We develop an effective medium theory to obtain effective permittivity of a composite of two-dimensional (2D) aligned single-walled carbon nanotubes. Electronic excitations on each nanotube surface are modeled by an infinitesimally thin layer of a 2D electron gas represented by two interacting fluids, which takes into account different nature of the σ and π electrons. Calculations of both real and imaginary parts of the effective dielectric function of the system are presented, for different values of the filling factor and radius of carbon nanotubes.

Phosphoglucose isomerase from bananas: partial characterization and relation to main changes in carbohydrate composition during ripening.

PubMed

Cordenunsi, B R; Oliveira do Nascimento, J R; Vieira da Mota, R; Lajolo, F M

2001-10-01

Some characteristics of phosphoglucose isomerase (PGI, EC 5.3.1.9) from banana were measured during fruit ripening of three banana cultivars. In banana, PGI was present as two dimeric isoenzymes, named PGI1 and PGI2, which had similar native molecular masses but differed in relation to heat stability and isoelectric point. Total PGI activity showed a distinct two-step change during fruit ripening. Before the climacteric period, PGI activity gradually decreased with the starch content, then its activity began to increase with sucrose accumulation. The ratio of PGI1, and PGI2 was constant, indicating that both enzymes would be involved in starch degradation and sucrose synthesis. PGI activity and changes in carbohydrate composition suggests the existence of some control to fit the requirements of the intense carbon flow from starch to sucrose.

Effects of a pre-and post-workout protein-carbohydrate supplement in trained crossfit individuals.

PubMed

Outlaw, Jordan J; Wilborn, Colin D; Smith-Ryan, Abbie E; Hayward, Sara E; Urbina, Stacie L; Taylor, Lem W; Foster, Cliffa A

2014-01-01

The purpose was to assess effects of a pre- and a post-workout protein-carbohydrate supplement on CrossFit-specific performance and body composition. In an open label randomized study, 13 male and 16 female trained Crossfit participants (mean ± SD; age: 31.87 ± 7.61 yrs, weight: 78.68 ± 16.45 kg, percent body fat: 21.97 ± 9.02) were assessed at 0 and 6 weeks for body composition, VO2max, Wingate peak (WPP) and mean power (WMP), in addition to sport-specific workouts (WOD1: 500 m row, 40 wall balls, 30 push-ups, 20 box jumps, 10 thrusters for time; WOD2: 15 minutes to complete an 800 m run "buy in", followed by as many rounds as possible (AMRAP) of 5 burpees, 10 Kettlebell swings, 15 air squats). The supplement (SUP) group consisted of 19 g of a pre-workout drink (extracts of pomegranate, tart cherry, green and black tea) taken 30 minutes before and a post-workout protein (females: 20 g; males: 40 g) and carbohydrate (females: 40 g; males: 80 g) supplement consumed immediately after each workout. The control (CTL) group consumed only water one hour before or after workouts. Participants completed three (minimum) varied workouts per week at a CrossFit gym as typical to habitual training throughout the six week study. Data were analyzed by repeated measures ANOVA (p <0 .05), 95% Confidence Intervals, and Magnitude Inferences. There were no time × group interactions for body composition, WMP, or WOD1 based on ANOVA statistics. VO2MAX, WPP, and WOD2 results revealed that the pre/post supplements were likely beneficial after 95% Confidence Intervals and Magnitude Inferences analysis. The combination of proprietary supplements taken for 6 weeks may provide benefits during certain sport-specific performance in trained CrossFit athletes but not others.

The analysis of thin walled composite laminated helicopter rotor with hierarchical warping functions and finite element method

NASA Astrophysics Data System (ADS)

Zhu, Dechao; Deng, Zhongmin; Wang, Xingwei

2001-08-01

In the present paper, a series of hierarchical warping functions is developed to analyze the static and dynamic problems of thin walled composite laminated helicopter rotors composed of several layers with single closed cell. This method is the development and extension of the traditional constrained warping theory of thin walled metallic beams, which had been proved very successful since 1940s. The warping distribution along the perimeter of each layer is expanded into a series of successively corrective warping functions with the traditional warping function caused by free torsion or free bending as the first term, and is assumed to be piecewise linear along the thickness direction of layers. The governing equations are derived based upon the variational principle of minimum potential energy for static analysis and Rayleigh Quotient for free vibration analysis. Then the hierarchical finite element method is introduced to form a numerical algorithm. Both static and natural vibration problems of sample box beams are analyzed with the present method to show the main mechanical behavior of the thin walled composite laminated helicopter rotor.

Overexpression of PhEXPA1 increases cell size, modifies cell wall polymer composition and affects the timing of axillary meristem development in Petunia hybrida.

PubMed

Zenoni, Sara; Fasoli, Marianna; Tornielli, Giovanni Battista; Dal Santo, Silvia; Sanson, Andrea; de Groot, Peter; Sordo, Sara; Citterio, Sandra; Monti, Francesca; Pezzotti, Mario

2011-08-01

• Expansins are cell wall proteins required for cell enlargement and cell wall loosening during many developmental processes. The involvement of the Petunia hybrida expansin A1 (PhEXPA1) gene in cell expansion, the control of organ size and cell wall polysaccharide composition was investigated by overexpressing PhEXPA1 in petunia plants. • PhEXPA1 promoter activity was evaluated using a promoter-GUS assay and the protein's subcellular localization was established by expressing a PhEXPA1-GFP fusion protein. PhEXPA1 was overexpressed in transgenic plants using the cauliflower mosaic virus (CaMV) 35S promoter. Fourier transform infrared (FTIR) and chemical analysis were used for the quantitative analysis of cell wall polymers. • The GUS and GFP assays demonstrated that PhEXPA1 is present in the cell walls of expanding tissues. The constitutive overexpression of PhEXPA1 significantly affected expansin activity and organ size, leading to changes in the architecture of petunia plants by initiating premature axillary meristem outgrowth. Moreover, a significant change in cell wall polymer composition in the petal limbs of transgenic plants was observed. • These results support a role for expansins in the determination of organ shape, in lateral branching, and in the variation of cell wall polymer composition, probably reflecting a complex role in cell wall metabolism. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.

Tensile Response of Hoop Reinforced Multiaxially Braided Thin Wall Composite Tubes

NASA Astrophysics Data System (ADS)

Roy, Sree Shankhachur; Potluri, Prasad; Soutis, Constantinos

2017-04-01

This paper presents the tensile response of thin-walled composite tubes with multi-axial fibre architecture. A hybrid braid-wound layup has the potential to optimise the composite tube properties, however, stacking sequence plays a role in the failure mechanism. A braid-winding method has been used to produce stacked overwound braid layup [(±45°/0°)5/90°4]T. Influence of stacking sequence on premature failure of hoop layers has been reported. Under tensile loading, a cross-ply composite tube with the alternate stacking of hoop and axial fibre show hoop plies splitting similar to the overwound braided composite tube. However, splitting has been restricted by the surrounding axial plies and contained between the adjacent axial fibre tows. This observation suggests hoop layers sandwiched between braid layers will improve structural integrity. A near net shape architecture with three fibre orientation in a triaxial braid will provide additional support to prevent extensive damage for plies loaded in off-axis. Several notable observations for relatively open braid structures such as tow scissoring, high Poisson's ratio and influence of axial tow crimp on the strain to failure have been reported. Digital Image Correlation (DIC) in conjunction with surface strain gauging has been employed to capture the strain pattern.

Chemical Synthesis of Oligosaccharides Related to the Cell Walls of Plants and Algae.

PubMed

Kinnaert, Christine; Daugaard, Mathilde; Nami, Faranak; Clausen, Mads H

2017-09-13

Plant cell walls are composed of an intricate network of polysaccharides and proteins that varies during the developmental stages of the cell. This makes it very challenging to address the functions of individual wall components in cells, especially for highly complex glycans. Fortunately, structurally defined oligosaccharides can be used as models for the glycans, to study processes such as cell wall biosynthesis, polysaccharide deposition, protein-carbohydrate interactions, and cell-cell adhesion. Synthetic chemists have focused on preparing such model compounds, as they can be produced in good quantities and with high purity. This Review contains an overview of those plant and algal polysaccharides that have been elucidated to date. The majority of the content is devoted to detailed summaries of the chemical syntheses of oligosaccharide fragments of cellulose, hemicellulose, pectin, and arabinogalactans, as well as glycans unique to algae. Representative synthetic routes within each class are discussed in detail, and the progress in carbohydrate chemistry over recent decades is highlighted.

Physical modification of palm kernel meal improved available carbohydrate, physicochemical properties and in vitro digestibility in economic freshwater fish.

PubMed

Thongprajukaew, Karun; Yawang, Pinya; Dudae, Lateepah; Bilanglod, Husna; Dumrongrittamatt, Terdtoon; Tantikitti, Chutima; Kovitvadhi, Uthaiwan

2013-12-01

Unavailable carbohydrates are an important limiting factor for utilization of palm kernel meal (PKM) as aquafeed ingredients. The aim of this study was to improve available carbohydrate from PKM. Different physical modifications including water soaking, microwave irradiation, gamma irradiation and electron beam, were investigated in relation to chemical composition, physicochemical properties and in vitro carbohydrate digestibility using digestive enzymes from economic freshwater fish. Modified methods had significant (P < 0.05) effects on chemical composition by decreasing crude fiber and increasing available carbohydrates. Improvements in physicochemical properties of PKM, such as water solubility, microstructure, relative crystallinity and lignocellulosic spectra, were mainly achieved by soaking and microwave irradiation. Carbohydrate digestibility varied among the physical modifications tested (P < 0.05) and three fish species had different abilities to digest PKM. Soaking was the appropriate modification for increasing carbohydrate digestion specifically in Nile tilapia (Oreochromis niloticus), whereas either soaking or microwave irradiation was effective for striped snakehead (Channa striata). For walking catfish (Clarias batrachus), carbohydrate digestibility was similar among raw, soaked and microwave-irradiated PKM. These findings suggest that soaking and microwave irradiation could be practical methods for altering appropriate physicochemical properties of PKM as well as increasing carbohydrate digestibility in select economic freshwater fish. © 2013 Society of Chemical Industry.

Mutational analysis of the glycosylphosphatidylinositol (GPI) anchor pathway demonstrates that GPI-anchored proteins are required for cell wall biogenesis and normal hyphal growth in Neurospora crassa.

PubMed

Bowman, Shaun M; Piwowar, Amy; Al Dabbous, Mash'el; Vierula, John; Free, Stephen J

2006-03-01

Using mutational and proteomic approaches, we have demonstrated the importance of the glycosylphosphatidylinositol (GPI) anchor pathway for cell wall synthesis and integrity and for the overall morphology of the filamentous fungus Neurospora crassa. Mutants affected in the gpig-1, gpip-1, gpip-2, gpip-3, and gpit-1 genes, which encode components of the N. crassa GPI anchor biosynthetic pathway, have been characterized. GPI anchor mutants exhibit colonial morphologies, significantly reduced rates of growth, altered hyphal growth patterns, considerable cellular lysis, and an abnormal "cell-within-a-cell" phenotype. The mutants are deficient in the production of GPI-anchored proteins, verifying the requirement of each altered gene for the process of GPI-anchoring. The mutant cell walls are abnormally weak, contain reduced amounts of protein, and have an altered carbohydrate composition. The mutant cell walls lack a number of GPI-anchored proteins, putatively involved in cell wall biogenesis and remodeling. From these studies, we conclude that the GPI anchor pathway is critical for proper cell wall structure and function in N. crassa.

Mutational Analysis of the Glycosylphosphatidylinositol (GPI) Anchor Pathway Demonstrates that GPI-Anchored Proteins Are Required for Cell Wall Biogenesis and Normal Hyphal Growth in Neurospora crassa

PubMed Central

Bowman, Shaun M.; Piwowar, Amy; Al Dabbous, Mash'el; Vierula, John; Free, Stephen J.

2006-01-01

Using mutational and proteomic approaches, we have demonstrated the importance of the glycosylphosphatidylinositol (GPI) anchor pathway for cell wall synthesis and integrity and for the overall morphology of the filamentous fungus Neurospora crassa. Mutants affected in the gpig-1, gpip-1, gpip-2, gpip-3, and gpit-1 genes, which encode components of the N. crassa GPI anchor biosynthetic pathway, have been characterized. GPI anchor mutants exhibit colonial morphologies, significantly reduced rates of growth, altered hyphal growth patterns, considerable cellular lysis, and an abnormal “cell-within-a-cell” phenotype. The mutants are deficient in the production of GPI-anchored proteins, verifying the requirement of each altered gene for the process of GPI-anchoring. The mutant cell walls are abnormally weak, contain reduced amounts of protein, and have an altered carbohydrate composition. The mutant cell walls lack a number of GPI-anchored proteins, putatively involved in cell wall biogenesis and remodeling. From these studies, we conclude that the GPI anchor pathway is critical for proper cell wall structure and function in N. crassa. PMID:16524913

The Specific Nature of Plant Cell Wall Polysaccharides 1

PubMed Central

Nevins, Donald J.; English, Patricia D.; Albersheim, Peter

1967-01-01

Polysaccharide compositions of cell walls were assessed by quantitative analyses of the component sugars. Cell walls were hydrolyzed in 2 n trifluoroacetic acid and the liberated sugars reduced to their respective alditols. The alditols were acetylated and the resulting alditol acetates separated by gas chromatography. Quantitative assay of the alditol acetates was accomplished by electronically integrating the detector output of the gas chromatograph. Myo-inositol, introduced into the sample prior to hydrolysis, served as an internal standard. The cell wall polysaccharide compositions of plant varieties within a given species are essentially identical. However, differences in the sugar composition were observed in cell walls prepared from different species of the same as well as of different genera. The fact that the wall compositions of different varieties of the same species are the same indicates that the biosynthesis of cell wall polysaccharides is genetically regulated. The cell walls of various morphological parts (roots, hypocotyls, first internodes and primary leaves) of bean plants were each found to have a characteristic sugar composition. It was found that the cell wall sugar composition of suspension-cultured sycamore cells could be altered by growing the cells on different carbon sources. This demonstrates that the biosynthesis of cell wall polysaccharides can be manipulated without fatal consequences. PMID:16656594

Building a plant cell wall at a glance.

PubMed

Lampugnani, Edwin R; Khan, Ghazanfar Abbas; Somssich, Marc; Persson, Staffan

2018-01-29

Plant cells are surrounded by a strong polysaccharide-rich cell wall that aids in determining the overall form, growth and development of the plant body. Indeed, the unique shapes of the 40-odd cell types in plants are determined by their walls, as removal of the cell wall results in spherical protoplasts that are amorphic. Hence, assembly and remodeling of the wall is essential in plant development. Most plant cell walls are composed of a framework of cellulose microfibrils that are cross-linked to each other by heteropolysaccharides. The cell walls are highly dynamic and adapt to the changing requirements of the plant during growth. However, despite the importance of plant cell walls for plant growth and for applications that we use in our daily life such as food, feed and fuel, comparatively little is known about how they are synthesized and modified. In this Cell Science at a Glance article and accompanying poster, we aim to illustrate the underpinning cell biology of the synthesis of wall carbohydrates, and their incorporation into the wall, in the model plant Arabidopsis . © 2018. Published by The Company of Biologists Ltd.

Carbohydrates as allergens.

PubMed

Commins, Scott P

2015-01-01

Complex carbohydrates are effective inducers of Th2 responses, and carbohydrate antigens can stimulate the production of glycan-specific antibodies. In instances where the antigen exposure occurs through the skin, the resulting antibody production can contain IgE class antibody. The glycan-stimulated IgE may be non-specific but may also be antigen specific. This review focuses on the production of cross-reactive carbohydrate determinants, the recently identified IgE antibody response to a mammalian oligosaccharide epitope, galactose-alpha-1,3-galactose (alpha-gal), as well as discusses practical implications of carbohydrates in allergy. In addition, the biological effects of carbohydrate antigens are reviewed in setting of receptors and host recognition.

Function and Dynamics of Auxin and Carbohydrates during Earlywood/Latewood Transition in Scots Pine1

PubMed Central

Uggla, Claes; Magel, Elisabeth; Moritz, Thomas; Sundberg, Björn

2001-01-01

In temperate regions the annual pattern of wood development is characterized by the formation of radially narrow and thick walled latewood cells. This takes place at the later part of the growing season when cambial cell division declines. To gain new insight into the regulation of this process, micro-analytical techniques were used to visualize the distribution of indole-3-acetic acid (IAA), soluble carbohydrates, and activities of sucrose (Suc)-metabolizing enzymes across the cambial region tissues in Scots pine (Pinus sylvestris). The total amount of IAA in the cambial region did not change with latewood initiation. But its radial distribution pattern was altered, resulting in an increased concentration in the cambial meristem and its recent derivatives. Thus, initiation of latewood formation and cessation of cambial cell division is not a consequence of decreased IAA concentrations in dividing and expanding cells. Rather, IAA most likely has a role in defining the altered developmental pattern associated with latewood formation. Carbohydrates and enzyme activities showed distinctive radial distribution patterns. Suc peaked in the phloem and decreased sharply to low levels across the cambial zone, whereas fructose and glucose reached their highest levels in the maturing tracheids. Suc synthase was the dominating Suc cleaving enzyme with a peak in the secondary wall-forming tracheids and in the phloem. Soluble acid invertase peaked in dividing and expanding cells. Suc-phosphate synthase had its highest activities in the phloem. Activities of cell wall bound invertase were low. The absence of major seasonal variations indicates that carbohydrate availability is not a trigger for latewood initiation. However, steep concentration gradients of the sugars suggest a role for sugar signaling in vascular development. PMID:11299382

Hybrid Composite Using Natural Filler and Multi-Walled Carbon Nanotubes (MWCNTs)

NASA Astrophysics Data System (ADS)

Nabinejad, Omid; Sujan, D.; Rahman, Muhammad Ekhlasur; Liew, Willey Yun Hsien; Davies, Ian J.

2017-12-01

This paper presents an experimental study on the development of hybrid composites comprising of multi-walled carbon nanotubes (MWCNTs) and natural filler (oil palm shell (OPS) powder) within unsaturated polyester (UP) matrix. The results revealed that the dispersion of pristine MWCNTs in the polymer matrix was strongly enhanced through use of the solvent mixing method assisted by ultrasonication. Four different solvents were investigated, namely, ethanol, methanol, styrene and acetone. The best compatibility with minimum side effects on the curing of the polyester resin was exhibited by the styrene solvent and this produced the maximum tensile and flexural properties of the resulting nanocomposites. A relatively small amount of pristine MWCNTs well dispersed within the natural filler polyester composite was found to be capable of improving mechanical properties of hybrid composite. However, increasing the MWCNT amount resulted in increased void content within the matrix due to an associated rapid increase in viscosity of the mixture during processing. Due to this phenomenon, the maximum tensile and flexural strengths of the hybrid composites were achieved at MWCNT contents of 0.2 to 0.4 phr and then declined for higher MWCNT amounts. The flexural modulus also experienced its peak at 0.4 phr MWCNT content whereas the tensile modulus exhibited a general decrease with increasing MWCNT content. Thermal stability analysis using TGA under an oxidative atmosphere showed that adding MWCNTs shifted the endset degradation temperature of the hybrid composite to a higher temperature.

Regulation of cell wall biosynthesis.

PubMed

Zhong, Ruiqin; Ye, Zheng-Hua

2007-12-01

Plant cell walls differ in their amount and composition among various cell types and even in different microdomains of the wall of a given cell. Plants must have evolved regulatory mechanisms controlling biosynthesis, targeted secretion, and assembly of wall components to achieve the heterogeneity in cell walls. A number of factors, including hormones, the cytoskeleton, glycosylphosphatidylinositol-anchored proteins, phosphoinositides, and sugar nucleotide supply, have been implicated in the regulation of cell wall biosynthesis or deposition. In the past two years, there have been important discoveries in transcriptional regulation of secondary wall biosynthesis. Several transcription factors in the NAC and MYB families have been shown to be the key switches for activation of secondary wall biosynthesis. These studies suggest a transcriptional network comprised of a hierarchy of transcription factors is involved in regulating secondary wall biosynthesis. Further investigation and integration of the regulatory players participating in the making of cell walls will certainly lead to our understanding of how wall amounts and composition are controlled in a given cell type. This may eventually allow custom design of plant cell walls on the basis of our needs.

The nonlinear bending response of thin-walled laminated composite cylinders

NASA Technical Reports Server (NTRS)

Fuchs, Hannes P.; Hyer, Michael W.

1992-01-01

The geometrically nonlinear Donnell shell theory is applied to the problem of stable bending of thin-walled circular cylinders. Responses are computed for cylinders with a radius-to-thickness ratio of 50 and length-to-radius ratios of 1 and 5. Four laminated composite cylinders and an aluminum cylinder are considered. Critical moment estimates are presented for short cylinders for which compression-type buckling behavior is important, and for very long cylinders for which the cross-section flattening, i.e., Brazier effect, is important. A finite element analysis is used to estimate the critical end rotation in addition to establishing the range of validity of the prebuckling analysis. The radial displacement response shows that the character of the boundary layer is significantly influenced by the geometric nonlinearities. Application of a first ply failure analysis using the maximum stress criterion suggests that in nearly all instances material failure occurs before buckling. Failure of the composite cylinders can be attributed to fiber breakage. Striking similarities are seen between the prebuckling displacements of the bending problem and axial compression problem for short cylinders.

Adherence to low‐carbohydrate and low‐fat diets in relation to weight loss and cardiovascular risk factors

PubMed Central

Yao, L.; Reynolds, K.; Niu, T.; Li, S.; Whelton, P. K.; He, J.; Steffen, L. M.; Bazzano, L. A.

2016-01-01

Summary Objective A low‐carbohydrate diet can reduce body weight and some cardiovascular disease risk factors more than a low‐fat diet, but differential adherence may play a role in these effects. Methods Data were used from 148 adults who participated in a 12‐month clinical trial examining the effect of a low‐carbohydrate diet (<40 g d−1) and a low‐fat diet (<30% fat and <7% saturated fat) on weight and cardiovascular disease risk factors. We compared attendance at counselling sessions, deviation from nutrient goals, urinary ketone presence and composite scores representing the overall adherence based on the distribution of these individual indicators between two interventions. Results Composite scores were similar between the two groups. A one‐interquartile‐range increase in composite score representing better adherence to a low‐carbohydrate diet was associated with 2.2 kg or 2.3% greater weight loss, 1.1 greater reduction in percent fat mass and 1.3 greater increase in proportion of lean mass. Indicators of adherence to a low‐fat diet were not associated with changes in weight, fat mass or lean mass. Conclusions Despite comparable adherence between groups, a low‐carbohydrate diet was associated with greater reductions in body weight and improvement in body composition, while a low‐fat diet was not associated with weight loss. PMID:27114827

Synthesis and Characterization of Multi Wall Carbon Nanotubes (MWCNT) Reinforced Sintered Magnesium Matrix Composites

NASA Astrophysics Data System (ADS)

Vijaya Bhaskar, S.; Rajmohan, T.; Palanikumar, K.; Bharath Ganesh Kumar, B.

2016-04-01

Metal matrix composites (MMCs) reinforced with ceramic nano particles (less than 100 nm), termed as metal matrix nano composites (MMNCs), can overcome those disadvantages associated with the conventional MMCs. MMCs containing carbon nanotubes are being developed and projected for diverse applications in various fields of engineering like automotive, avionic, electronic and bio-medical sectors. The present investigation deals with the synthesis and characterization of hybrid magnesium matrix reinforced with various different wt% (0-0.45) of multi wall carbon nano tubes (MWCNT) and micro SiC particles prepared through powder metallurgy route. Microstructure and mechanical properties such as micro hardness and density of the composites were examined. Microstructure of MMNCs have been investigated by scanning electron microscope, X-ray diffraction and energy dispersive X-ray spectroscopy (EDS) for better observation of dispersion of reinforcement. The results indicated that the increase in wt% of MWCNT improves the mechanical properties of the composite.

Carbohydrates and the human gut microbiota.

PubMed

Chassard, Christophe; Lacroix, Christophe

2013-07-01

Due to its scale and its important role in maintaining health, the gut microbiota can be considered as a 'new organ' inside the human body. Many complex carbohydrates are degraded and fermented by the human gut microbiota in the large intestine to both yield basic energy salvage and impact gut health through produced metabolites. This review will focus on the gut microbes and microbial mechanisms responsible for polysaccharides degradation and fermentation in the large intestine. Gut microbes and bacterial metabolites impact the host at many levels, including modulation of inflammation, and glucose and lipid metabolisms. A complex relationship occurs in the intestine between the human gut microbiota, diet and the host. Research on carbohydrates and gut microbiota composition and functionality is fast developing and will open opportunities for prevention and treatment of obesity, diabetes and other related metabolic disorders through manipulation of the gut ecosystem.

Low-temperature carbonization and more effective degradation of carbohydrates induced by ferric trichloride.

PubMed

Xia, Juan; Song, Le Xin; Dang, Zheng

2012-07-05

The present work is devoted to an attempt to understand the effect of an inorganic salt such as ferric trichloride (FeCl(3)) on the carbonization and degradation of carbohydrates such as β-cyclodextrin (CD), amylose, and cellulose. Our data revealed two important observations. First, the presence of FeCl(3) led to the occurrence of a low carbonization temperature of 373 K. This is a rare phenomenon, in which carbonization improvement is present even if a small amount of FeCl(3) was added. Experimental results had provided evidence for the fact that a redox process was started during the low-temperature carbonization of β-CD, causing the reduction of FeCl(3) to ferrous chloride (FeCl(2)) by carbon materials formed in the carbonization process in air. However, the reduction process of FeCl(3) produced the in situ composite nanomaterial of Fe-FeCl(2) combination in nitrogen. Second, a molecule-ion interaction emerged between FeCl(3) and the carbohydrates in aqueous solution, resulting in a more effective degradation of the carbohydrates. Moreover, our results demonstrated that FeCl(3) played the role of a catalyst during the degradation of the carbohydrates in solution. We believe that the current work not only has a significant potential application in disposal of waste carbohydrates but also could be helpful in many fields such as environmental protection, biomass energy development, and inorganic composite nanomaterials.

Plant cell walls throughout evolution: towards a molecular understanding of their design principles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sarkar, Purbasha; Bosneaga, Elena; Auer, Manfred

Throughout their life, plants typically remain in one location utilizing sunlight for the synthesis of carbohydrates, which serve as their sole source of energy as well as building blocks of a protective extracellular matrix, called the cell wall. During the course of evolution, plants have repeatedly adapted to their respective niche,which is reflected in the changes of their body plan and the specific design of cell walls. Cell walls not only changed throughout evolution but also are constantly remodelled and reconstructed during the development of an individual plant, and in response to environmental stress or pathogen attacks. Carbohydrate-rich cell wallsmore » display complex designs, which together with the presence of phenolic polymers constitutes a barrier for microbes, fungi, and animals. Throughout evolution microbes have co-evolved strategies for efficient breakdown of cell walls. Our current understanding of cell walls and their evolutionary changes are limited as our knowledge is mainly derived from biochemical and genetic studies, complemented by a few targeted yet very informative imaging studies. Comprehensive plant cell wall models will aid in the re-design of plant cell walls for the purpose of commercially viable lignocellulosic biofuel production as well as for the timber, textile, and paper industries. Such knowledge will also be of great interest in the context of agriculture and to plant biologists in general. It is expected that detailed plant cell wall models will require integrated correlative multimodal, multiscale imaging and modelling approaches, which are currently underway.« less

Comparison of weight-loss diets with different compositions of fat, protein, and carbohydrates.

PubMed

Sacks, Frank M; Bray, George A; Carey, Vincent J; Smith, Steven R; Ryan, Donna H; Anton, Stephen D; McManus, Katherine; Champagne, Catherine M; Bishop, Louise M; Laranjo, Nancy; Leboff, Meryl S; Rood, Jennifer C; de Jonge, Lilian; Greenway, Frank L; Loria, Catherine M; Obarzanek, Eva; Williamson, Donald A

2009-02-26

The possible advantage for weight loss of a diet that emphasizes protein, fat, or carbohydrates has not been established, and there are few studies that extend beyond 1 year. We randomly assigned 811 overweight adults to one of four diets; the targeted percentages of energy derived from fat, protein, and carbohydrates in the four diets were 20, 15, and 65%; 20, 25, and 55%; 40, 15, and 45%; and 40, 25, and 35%. The diets consisted of similar foods and met guidelines for cardiovascular health. The participants were offered group and individual instructional sessions for 2 years. The primary outcome was the change in body weight after 2 years in two-by-two factorial comparisons of low fat versus high fat and average protein versus high protein and in the comparison of highest and lowest carbohydrate content. At 6 months, participants assigned to each diet had lost an average of 6 kg, which represented 7% of their initial weight; they began to regain weight after 12 months. By 2 years, weight loss remained similar in those who were assigned to a diet with 15% protein and those assigned to a diet with 25% protein (3.0 and 3.6 kg, respectively); in those assigned to a diet with 20% fat and those assigned to a diet with 40% fat (3.3 kg for both groups); and in those assigned to a diet with 65% carbohydrates and those assigned to a diet with 35% carbohydrates (2.9 and 3.4 kg, respectively) (P>0.20 for all comparisons). Among the 80% of participants who completed the trial, the average weight loss was 4 kg; 14 to 15% of the participants had a reduction of at least 10% of their initial body weight. Satiety, hunger, satisfaction with the diet, and attendance at group sessions were similar for all diets; attendance was strongly associated with weight loss (0.2 kg per session attended). The diets improved lipid-related risk factors and fasting insulin levels. Reduced-calorie diets result in clinically meaningful weight loss regardless of which macronutrients they emphasize

Comparison of Weight-Loss Diets with Different Compositions of Fat, Protein, and Carbohydrates

PubMed Central

Sacks, Frank M.; Bray, George A.; Carey, Vincent J.; Smith, Steven R.; Ryan, Donna H.; Anton, Stephen D.; McManus, Katherine; Champagne, Catherine M.; Bishop, Louise M.; Laranjo, Nancy; Leboff, Meryl S.; Rood, Jennifer C.; de Jonge, Lilian; Greenway, Frank L.; Loria, Catherine M.; Obarzanek, Eva; Williamson, Donald A.

2009-01-01

BACKGROUND The possible advantage for weight loss of a diet that emphasizes protein, fat, or carbohydrates has not been established, and there are few studies that extend beyond 1 year. METHODS We randomly assigned 811 overweight adults to one of four diets; the targeted percentages of energy derived from fat, protein, and carbohydrates in the four diets were 20, 15, and 65%; 20, 25, and 55%; 40, 15, and 45%; and 40, 25, and 35%. The diets consisted of similar foods and met guidelines for cardiovascular health. The participants were offered group and individual instructional sessions for 2 years. The primary outcome was the change in body weight after 2 years in two-by-two factorial comparisons of low fat versus high fat and average protein versus high protein and in the comparison of highest and lowest carbohydrate content. RESULTS At 6 months, participants assigned to each diet had lost an average of 6 kg, which represented 7% of their initial weight; they began to regain weight after 12 months. By 2 years, weight loss remained similar in those who were assigned to a diet with 15% protein and those assigned to a diet with 25% protein (3.0 and 3.6 kg, respectively); in those assigned to a diet with 20% fat and those assigned to a diet with 40% fat (3.3 kg for both groups); and in those assigned to a diet with 65% carbohydrates and those assigned to a diet with 35% carbohydrates (2.9 and 3.4 kg, respectively) (P>0.20 for all comparisons). Among the 80% of participants who completed the trial, the average weight loss was 4 kg; 14 to 15% of the participants had a reduction of at least 10% of their initial body weight. Satiety, hunger, satisfaction with the diet, and attendance at group sessions were similar for all diets; attendance was strongly associated with weight loss (0.2 kg per session attended). The diets improved lipid-related risk factors and fasting insulin levels. CONCLUSIONS Reduced-calorie diets result in clinically meaningful weight loss regardless of

8th Annual Glycoscience Symposium: Integrating Models of Plant Cell Wall Structure, Biosynthesis and Assembly

DOE Office of Scientific and Technical Information (OSTI.GOV)

Azadi, Paratoo

2015-09-24

The Complex Carbohydrate Research Center (CCRC) of the University of Georgia holds a symposium yearly that highlights a broad range of carbohydrate research topics. The 8th Annual Georgia Glycoscience Symposium entitled “Integrating Models of Plant Cell Wall Structure, Biosynthesis and Assembly” was held on April 7, 2014 at the CCRC. The focus of symposium was on the role of glycans in plant cell wall structure and synthesis. The goal was to have world leaders in conjunction with graduate students, postdoctoral fellows and research scientists to propose the newest plant cell wall models. The symposium program closely followed the DOE’s missionmore » and was specifically designed to highlight chemical and biochemical structures and processes important for the formation and modification of renewable plant cell walls which serve as the basis for biomaterial and biofuels. The symposium was attended by both senior investigators in the field as well as students including a total attendance of 103, which included 80 faculty/research scientists, 11 graduate students and 12 Postdoctoral students.« less

Effect of Continuous Multi-Walled Carbon Nanotubes on Thermal and Mechanical Properties of Flexible Composite Film

PubMed Central

Cha, Ji Eun; Kim, Seong Yun; Lee, Seung Hee

2016-01-01

To investigate the effect of continuous multi-walled carbon nanotubes (MWCNTs) on the thermal and mechanical properties of composites, we propose a fabrication method for a buckypaper-filled flexible composite film prepared by a two-step process involving buckypaper fabrication using vacuum filtration of MWCNTs, and composite film fabrication using the dipping method. The thermal conductivity and tensile strength of the composite film filled with the buckypaper exhibited improved results, respectively 76% and 275% greater than those of the individual MWCNT-filled composite film. It was confirmed that forming continuous MWCNT fillers is an important factor which determines the physical characteristics of the composite film. In light of the study findings, composite films using buckypaper as a filler and polydimethylsiloxane (PDMS) as a flexible matrix have sufficient potential to be applied as a heat-dissipating material, and as a flexible film with high thermal conductivity and excellent mechanical properties. PMID:28335310

Carbohydrates in Supramolecular Chemistry.

PubMed

Delbianco, Martina; Bharate, Priya; Varela-Aramburu, Silvia; Seeberger, Peter H

2016-02-24

Carbohydrates are involved in a variety of biological processes. The ability of sugars to form a large number of hydrogen bonds has made them important components for supramolecular chemistry. We discuss recent advances in the use of carbohydrates in supramolecular chemistry and reveal that carbohydrates are useful building blocks for the stabilization of complex architectures. Systems are presented according to the scaffold that supports the glyco-conjugate: organic macrocycles, dendrimers, nanomaterials, and polymers are considered. Glyco-conjugates can form host-guest complexes, and can self-assemble by using carbohydrate-carbohydrate interactions and other weak interactions such as π-π interactions. Finally, complex supramolecular architectures based on carbohydrate-protein interactions are discussed.

Dietary composition of carbohydrates contributes to the development of experimental type 2 diabetes.

PubMed

Hodgson, K; Govan, B; Ketheesan, N; Morris, J

2013-04-01

Evidence has emerged supporting a link between high glycaemic index (GI) diets and type 2 diabetes (T2D). The aim of this study was to determine if dietary GI influences the development of hyperglycaemia in C57BL/6 mice to more closely reflect T2D. Male C57BL/6 mice (n=30) were randomly divided into 3 dietary groups consisting of either standard rodent chow (4.8 % fat, 20 % protein), or a high fat (HF) diet (21-23 % fat, 19 % protein) with low GI (15.4 % starch; HF-LG) or high GI (50.5 % dextrose; HF-HG) ad libitum for 10 weeks. Body weight, blood glucose, glucose tolerance, and circulating cholesterol and triglyceride levels were measured for the duration of the study. We found that increasing the GI of a moderately HF diet induces severe hyperglycaemia and insulin resistance in C57BL/6 mice, reflective of criteria for diagnosis of T2D, whilst littermates consuming an equivalent low GI diet maintain glucose homeostasis. This study demonstrates the significant contribution of both dietary carbohydrate and fat composition in the aetiopathogenesis of T2D.

In Situ Identification of Pigment Composition and Particle Size on Wall Paintings Using Visible Spectroscopy as a Noninvasive Measurement Method.

PubMed

Li, Junfeng; Wan, Xiaoxia; Bu, Yajing; Li, Chan; Liang, Jinxing; Liu, Qiang

2016-11-01

Noninvasive examination methods of chemical composition and particle size are presented here based on visible spectroscopy to achieve the identification and recording of mineral pigments used on ancient wall paintings. The normalized spectral curve, slope and curvature extracted from visible spectral reflectance are combined with adjustable weighting coefficients to construct the identification feature space, and Euclid distances between spectral reflectance from wall paintings and a reference database are calculated in the feature space as the discriminant criterion to identify the chemical composition of mineral pigments. A parametric relationship between the integral quantity of spectral reflectance and logarithm of mean particle size is established using a quadratic polynomial to accomplish the noninvasive prediction of mineral pigment particle size used on ancient wall paintings. The feasibility of the proposed methods is validated by the in situ nondestructive identification of the wall paintings in the Mogao Grottoes at Dunhuang. Chinese painting styles and historical evolution are then analyzed according to the identification results of 16 different grottoes constructed from the Sixteen Kingdoms to the Yuan Dynasty. © The Author(s) 2016.

Altering carbon allocation in hybrid poplar (Populus alba × grandidentata) impacts cell wall growth and development.

PubMed

Unda, Faride; Kim, Hoon; Hefer, Charles; Ralph, John; Mansfield, Shawn D

2017-07-01

Galactinol synthase is a pivotal enzyme involved in the synthesis of the raffinose family of oligosaccharides (RFOs) that function as transport carbohydrates in the phloem, as storage compounds in sink tissues and as soluble metabolites that combat both abiotic and biotic stress in several plant species. Hybrid poplar (Populus alba × grandidentata) overexpressing the Arabidopsis thaliana GolS3 (AtGolS3) gene showed clear effects on development; the extreme overexpressing lines were stunted and had cell wall traits characteristic of tension wood, whereas lines with only moderate up-regulation grew normally and had moderately altered secondary cell wall composition and ultrastructure. Stem cross-sections of the developing xylem revealed a significant increase in the number of vessels, as well as the clear presence of a G-layer in the fibres. Furthermore, AtGolS3-OE lines possessed higher cellulose and lower lignin contents, an increase in cellulose crystallinity, and significantly altered hemicellulose-derived carbohydrates, notably manifested by their mannose and xylose contents. In addition, the transgenic plants displayed elevated xylem starch content. Transcriptome interrogation of the transgenic plants showed a significant up-regulation of genes involved in the synthesis of myo-inositol, along with genes involved in sucrose degradation. The results suggest that the overexpression of GolS and its product galactinol may serve as a molecular signal that initiates metabolic changes, culminating in a change in cell wall development and potentially the formation of tension wood. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Compositional Analysis of Whole Grains, Processed Grains, Grain Co-Products, and Other Carbohydrate Sources with Applicability to Pet Animal Nutrition

PubMed Central

Beloshapka, Alison N.; Buff, Preston R.; Fahey, George C.; Swanson, Kelly S.

2016-01-01

Our objective was to measure the proximate, starch, amino acid, and mineral compositions of grains, grain co-products, and other carbohydrate sources with potential use in pet foods. Thirty-two samples from barley (barley flake, cut barley, ground pearled barley, malted barley, whole pearled barley, pearled barley flakes, and steamed rolled barley); oats (groats, ground oatmeal, ground steamed groats, instant oats, oat bran, oat fiber, oat flour, quick oats, regular rolled oats, steamed rolled oat groats, and steel cut groats); rice (brown rice, polished rice, defatted rice bran, and rice flour); and miscellaneous carbohydrate sources (canary grass seed, hulled millet, whole millet, quinoa, organic spelt hull pellets, potato flake, sorghum, whole wheat, and whole yellow corn) were analyzed. Crude protein, amino acid, fat, dietary fiber, resistant starch, and mineral concentrations were highly variable among the respective fractions (i.e., barley flake vs. malted barley vs. steamed rolled barley) as well as among the various grains (i.e., barley flake vs. brown rice vs. canary grass seed). These ingredients not only provide a readily available energy source, but also a source of dietary fiber, resistant starch, essential amino acids, and macrominerals for pet diets. PMID:28231117

Transmission electron microscopy, fluorescence microscopy, and confocal raman microscopic analysis of ultrastructural and compositional heterogeneity of Cornus alba L. wood cell wall.

PubMed

Ma, Jianfeng; Ji, Zhe; Zhou, Xia; Zhang, Zhiheng; Xu, Feng

2013-02-01

Transmission electron microscopy (TEM), fluorescence microscopy, and confocal Raman microscopy can be used to characterize ultrastructural and compositional heterogeneity of plant cell walls. In this study, TEM observations revealed the ultrastructural characterization of Cornus alba L. fiber, vessel, axial parenchyma, ray parenchyma, and pit membrane between cells, notably with the ray parenchyma consisting of two well-defined layers. Fluorescence microscopy evidenced that cell corner middle lamella was more lignified than adjacent compound middle lamella and secondary wall with variation in lignification level from cell to cell. In situ Raman images showed that the inhomogeneity in cell wall components (cellulose and lignin) among different cells and within morphologically distinct cell wall layers. As the significant precursors of lignin biosynthesis, the pattern of coniferyl alcohol and aldehyde (joint abbreviation Lignin-CAA for both structures) distribution in fiber cell wall was also identified by Raman images, with higher concentration occurring in the fiber secondary wall where there was the highest cellulose concentration. Moreover, noteworthy was the observation that higher concentration of lignin and very minor amounts of cellulose were visualized in the pit membrane areas. These complementary microanalytical methods provide more accurate and complete information with regard to ultrastructural and compositional characterization of plant cell walls.

Compositional changes in 'Bartlett' pear ( Pyrus communis L.) cell wall polysaccharides as affected by sunlight conditions.

PubMed

Raffo, María D; Ponce, Nora M A; Sozzi, Gabriel O; Vicente, Ariel R; Stortz, Carlos A

2011-11-23

Preharvest conditions can have a great impact on fruit quality attributes and postharvest responses. Firmness is an important quality attribute in pear, and excessive softening increases susceptibility to bruising and decay, thus limiting fruit postharvest life. Textural characteristics of fruits are determined at least in part by cell wall structure and disassembly. Few studies have analyzed the influence of fruit preharvest environment in softening, cell wall composition, and degradation. In the current work 'Bartlett' pears grown either facing the sun (S) or in the shade (H) were harvested and stored for 13 days at 20 °C. An evaluation of fruit soluble solids, acidity, color, starch degradation, firmness, cell wall yield, pectin and matrix glycan solubilization, depolymerization, and monosaccharide composition was carried out. Sun-exposed pears showed more advanced color development and similar levels of starch degradation, sugars, and acids than shaded fruit. Sunlight-grown pears were at harvest firmer than shade-grown pears. Both fruit groups softened during storage at 20 °C, but even after ripening, sun-exposed pears remained firmer. Sunlight exposure did not have a great impact on pectin molecular weight. Instead, at harvest a higher proportion of water-solubilized uronic acids and alkali-solubilized neutral sugars and a larger mean molecular size of tightly bound glycans was found in sun-exposed pears. During ripening cell wall catabolism took place in both sun- and shade-grown pears, but pectin solubilization was clearly delayed in sun-exposed fruit. This was associated with decreased removal of RG I-arabinan side chains rather than with reduced depolymerization.

The name of the -ose: An editorial on carbohydrate nomenclature

USDA-ARS?s Scientific Manuscript database

What’s in a name? The term "sugar" is usually applied to the monosaccharides, disaccharides, and lower oligosaccharides, although "carbohydrate" ("hydrate de carbone") was originally used only for monosaccharides, because their composition can be expressed as Cn(H2O)n. Historically, sugars were name...

Pharmaceutical, cosmeceutical, and traditional applications of marine carbohydrates.

PubMed

Ahmed, Abdul Bakrudeen Ali; Adel, Mohaddeseh; Karimi, Pegah; Peidayesh, Mahvash

2014-01-01

Marine carbohydrates are most important organic molecules made by photosynthetic organisms. It is very essential for humankind: the role in being an energy source for the organism and they are considered as an important dissolve organic compound (DOC) in marine environment's sediments. Carbohydrates found in different marine environments in different concentrations. Polysaccharides of carbohydrates play an important role in various fields such as pharmaceutical, food production, cosmeceutical, and so on. Marine organisms are good resources of nutrients, and they are rich carbohydrate in sulfated polysaccharide. Seaweeds (marine microalgae) are used in different pharmaceutical industries, especially in pharmaceutical compound production. Seaweeds have a significant amount of sulfated polysaccharides, which are used in cosmeceutical industry, besides based on the biological applications. Since then, traditional people, cosmetics products, and pharmaceutical applications consider many types of seaweed as an important organism used in food process. Sulfated polysaccharides containing seaweed have potential uses in the blood coagulation system, antiviral activity, antioxidant activity, anticancer activity, immunomodulating activity, antilipidepic activity, etc. Some species of marine organisms are rich in polysaccharides such as sulfated galactans. Various polysaccharides such as agar and alginates, which are extracted from marine organisms, have several applications in food production and cosmeceutical industries. Due to their high health benefits, compound-derived extracts of marine polysaccharides have various applications and traditional people were using them since long time ago. In the future, much attention is supposed to be paid to unraveling the structural, compositional, and sequential properties of marine carbohydrate as well. © 2014 Elsevier Inc. All rights reserved.

The role of carbohydrates in seed germination and seedling establishment of Himatanthus sucuuba, an Amazonian tree with populations adapted to flooded and non-flooded conditions

PubMed Central

da Silva Ferreira, Cristiane; Piedade, Maria Teresa Fernandez; Tiné, Marco Aurélio Silva; Rossatto, Davi Rodrigo; Parolin, Pia; Buckeridge, Marcos Silveira

2009-01-01

Background and Aims In the Amazonian floodplains plants withstand annual periods of flooding which can last 7 months. Under these conditions seedlings remain submerged in the dark for long periods since light penetration in the water is limited. Himatanthus sucuuba is a tree species found in the ‘várzea’ (VZ) floodplains and adjacent non-flooded ‘terra-firme’ (TF) forests. Biochemical traits which enhance flood tolerance and colonization success of H. sucuuba in periodically flooded environments were investigated. Methods Storage carbohydrates of seeds of VZ and TF populations were extracted and analysed by HPAEC/PAD. Starch was analysed by enzyme (glucoamylase) degradation followed by quantification of glucose oxidase. Carbohydrate composition of roots of VZ and TF seedlings was studied after experimental exposure to a 15-d period of submersion in light versus darkness. Key Results The endosperm contains a large proportion of the seed reserves, raffinose being the main non-structural carbohydrate. Around 93 % of the cell wall storage polysaccharides (percentage dry weight basis) in the endosperm of VZ seeds was composed of mannose, while soluble sugars accounted for 2·5%. In contrast, 74 % of the endosperm in TF seeds was composed of galactomannans, while 22 % of the endosperm was soluble sugars. This suggested a larger carbohydrate allocation to germination in TF populations whereas VZ populations allocate comparatively more to carbohydrates mobilized during seedling development. The concentration of root non-structural carbohydrates in non-flooded seedlings strongly decreased after a 15-d period of darkness, whereas flooded seedlings were less affected. These effects were more pronounced in TF seedlings, which showed significantly lower root non-structural carbohydrate concentrations. Conclusions There seem to be metabolic adjustments in VZ but not TF seedlings that lead to adaptation to the combined stresses of darkness and flooding. This seems to be

Overexpression of SbMyb60 impacts phenylpropanoid biosynthesis and alters secondary cell wall composition in sorghum bicolor

USDA-ARS?s Scientific Manuscript database

The phenylpropanoid biosynthesis pathway that generates lignin subunits represents a significant target to alter the abundance and composition of lignin. The major regulators of phenylpropanoid metabolism are myb transcription factors, which have been shown to modulate secondary cell wall compositi...

Energy utilization of a low carbohydrate diet fed genetically obese rats and mice.

PubMed

Thenen, S W; Mayer, J

1977-02-01

Genetically obese Zucker rats, ob/ob mice and non-obese littermates were fed low carbohydrate (2%, 48%, and 50% of energy as carbohydrate, protein, and fat, respectively) and control (60%, 19%, and 21%, as carobhydrate, protein, and fat) diets. The oxidation of the energy components of these diets was measured by adding D-[U-14C]glucose, L-[U-14C]glutamic acid, and glyceryl tri-[1-14C]oleate to test meals given intragastrically and collecting respiratory CO2 for 4 hours. The animals responded to the low carbohydrate diet by oxidizing less glucose and more glutamic acid, but these amounts were proportional to dietary carbohydrate and protein composition, In contrast, the animals oxidized both higher amounts and percentages of glyceryl trioleate when fed the low carbohydrate diet. Obese Zucker rats oxidized less fat than non-obese rats when fed both diets, while obese mice oxidized fat to the same extent as non-obese mice. Feeding the low carbohydrate diet significantly increased body weight in the obese mice, but not in obese rats and non-obese mice and rats. The effect of obesity and the low carbohydrate diet on food intake, serum glucose and lipid values and CO2 production are also reported.

Cell wall evolution and diversity

PubMed Central

Fangel, Jonatan U.; Ulvskov, Peter; Knox, J. P.; Mikkelsen, Maria D.; Harholt, Jesper; Popper, Zoë A.; Willats, William G.T.

2012-01-01

Plant cell walls display a considerable degree of diversity in their compositions and molecular architectures. In some cases the functional significance of a particular cell wall type appears to be easy to discern: secondary cells walls are often reinforced with lignin that provides durability; the thin cell walls of pollen tubes have particular compositions that enable their tip growth; lupin seed cell walls are characteristically thickened with galactan used as a storage polysaccharide. However, more frequently the evolutionary mechanisms and selection pressures that underpin cell wall diversity and evolution are unclear. For diverse green plants (chlorophytes and streptophytes) the rapidly increasing availability of transcriptome and genome data sets, the development of methods for cell wall analyses which require less material for analysis, and expansion of molecular probe sets, are providing new insights into the diversity and occurrence of cell wall polysaccharides and associated biosynthetic genes. Such research is important for refining our understanding of some of the fundamental processes that enabled plants to colonize land and to subsequently radiate so comprehensively. The study of cell wall structural diversity is also an important aspect of the industrial utilization of global polysaccharide bio-resources. PMID:22783271

Preparation and characterization of bagasse/HDPE composites using multi-walled carbon nanotubes.

PubMed

Ashori, Alireza; Sheshmani, Shabnam; Farhani, Foad

2013-01-30

This article presents the preparation and characterization of bagasse/high density polyethylene (HDPE) composites. The effects of multi-walled carbon nanotubes (MWCNTs), as reinforcing agent, on the mechanical and physical properties were also investigated. In order to increase the interphase adhesion, maleic anhydride grafted polyethylene (MAPE) was added as a coupling agent to all the composites studied. In the sample preparation, MWCNTs and MAPE contents were used as variable factors. The morphology of the specimens was characterized using scanning electron microscopy (SEM) technique. The results of strength measurement indicated that when 1.5 wt% MWCNTs were added, tensile and flexural properties reached their maximum values. At high level of MWCNTs loading (3 or 4 wt%), increased population of MWCNTs lead to agglomeration and stress transfer gets blocked. The addition of MWCNTs filler slightly decreased the impact strength of composites. Both mechanical and physical properties were improved when 4 wt% MAPE was applied. SEM micrographs also showed that the surface roughness improved with increasing MAPE loading from 0 to 4 wt%. The improvement of physicomechanical properties of composites confirmed that MWCNTs have good reinforcement and the optimum synergistic effect of MWCNTs and MAPE was achieved at the combination of 1.5 and 4 wt%, respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.

Carbohydrate-Aromatic Interactions in Proteins.

PubMed

Hudson, Kieran L; Bartlett, Gail J; Diehl, Roger C; Agirre, Jon; Gallagher, Timothy; Kiessling, Laura L; Woolfson, Derek N

2015-12-09

Protein-carbohydrate interactions play pivotal roles in health and disease. However, defining and manipulating these interactions has been hindered by an incomplete understanding of the underlying fundamental forces. To elucidate common and discriminating features in carbohydrate recognition, we have analyzed quantitatively X-ray crystal structures of proteins with noncovalently bound carbohydrates. Within the carbohydrate-binding pockets, aliphatic hydrophobic residues are disfavored, whereas aromatic side chains are enriched. The greatest preference is for tryptophan with an increased prevalence of 9-fold. Variations in the spatial orientation of amino acids around different monosaccharides indicate specific carbohydrate C-H bonds interact preferentially with aromatic residues. These preferences are consistent with the electronic properties of both the carbohydrate C-H bonds and the aromatic residues. Those carbohydrates that present patches of electropositive saccharide C-H bonds engage more often in CH-π interactions involving electron-rich aromatic partners. These electronic effects are also manifested when carbohydrate-aromatic interactions are monitored in solution: NMR analysis indicates that indole favorably binds to electron-poor C-H bonds of model carbohydrates, and a clear linear free energy relationships with substituted indoles supports the importance of complementary electronic effects in driving protein-carbohydrate interactions. Together, our data indicate that electrostatic and electronic complementarity between carbohydrates and aromatic residues play key roles in driving protein-carbohydrate complexation. Moreover, these weak noncovalent interactions influence which saccharide residues bind to proteins, and how they are positioned within carbohydrate-binding sites.

Variable-viscosity thermal hemodynamic slip flow conveying nanoparticles through a permeable-walled composite stenosed artery

NASA Astrophysics Data System (ADS)

Akbar, Noreen Sher; Tripathi, Dharmendra; Bég, O. Anwar

2017-07-01

This paper presents a mathematical model for simulating viscous, incompressible, steady-state blood flow containing copper nanoparticles and coupled heat transfer through a composite stenosed artery with permeable walls. Wall slip hydrodynamic and also thermal buoyancy effects are included. The artery is simulated as an isotropic elastic tube, following Joshi et al. (2009), and a variable viscosity formulation is employed for the flowing blood. The equations governing the transport phenomena are non-dimensionalized and the resulting boundary value problem is solved analytically in the steady state subject to physically appropriate boundary conditions. Numerical computations are conducted to quantify the effects of relevant hemodynamic, thermophysical and nanoscale parameters emerging in the model on velocity and temperature profiles, wall shear stress, impedance resistance and also streamline distributions. The model may be applicable to drug fate transport modeling with nanoparticle agents and also to the optimized design of nanoscale medical devices for diagnosing stenotic diseases in circulatory systems.

Cell-wall architecture and lignin composition of wheat developed in a microgravity environment.

PubMed

Levine, L H; Heyenga, A G; Levine, H G; Choi, J; Davin, L B; Krikorian, A D; Lewis, N G

2001-07-01

The microgravity environment encountered during space-flight has long been considered to affect plant growth and developmental processes, including cell wall biopolymer composition and content. As a prelude to studying how microgravity is perceived - and acted upon - by plants, it was first instructive to investigate what gross effects on plant growth and development occurred in microgravity. Thus, wheat seedlings were exposed to microgravity on board the space shuttle Discovery (STS-51) for a 10 day duration, and these specimens were compared with their counterparts grown on Earth under the same conditions (e.g. controls). First, the primary roots of the wheat that developed under both microgravity and 1 g on Earth were examined to assess the role of gravity on cellulose microfibril (CMF) organization and secondary wall thickening patterns. Using a quick freeze/deep etch technique, this revealed that the cell wall CMFs of the space-grown wheat maintained the same organization as their 1 g-grown counterparts. That is, in all instances, CMFs were randomly interwoven with each other in the outermost layers (farthest removed from the plasma membrane), and parallel to each other within the individual strata immediately adjacent to the plasma membranes. The CMF angle in the innermost stratum relative to the immediately adjacent stratum was ca 80 degrees in both the space and Earth-grown plants. Second, all plants grown in microgravity had roots that grew downwards into the agar; they did not display "wandering" and upward growth as previously reported by others. Third, the space-grown wheat also developed normal protoxylem and metaxylem vessel elements with secondary thickening patterns ranging from spiral to regular pit to reticulate thickenings. Fourthly, both the space- and Earth-grown plants were essentially of the same size and height, and their lignin analyses revealed no substantial differences in their amounts and composition regardless of the gravitational

Cell-wall architecture and lignin composition of wheat developed in a microgravity environment

NASA Technical Reports Server (NTRS)

Levine, L. H.; Heyenga, A. G.; Levine, H. G.; Choi, J.; Davin, L. B.; Krikorian, A. D.; Lewis, N. G.; Sager, J. C. (Principal Investigator)

2001-01-01

The microgravity environment encountered during space-flight has long been considered to affect plant growth and developmental processes, including cell wall biopolymer composition and content. As a prelude to studying how microgravity is perceived - and acted upon - by plants, it was first instructive to investigate what gross effects on plant growth and development occurred in microgravity. Thus, wheat seedlings were exposed to microgravity on board the space shuttle Discovery (STS-51) for a 10 day duration, and these specimens were compared with their counterparts grown on Earth under the same conditions (e.g. controls). First, the primary roots of the wheat that developed under both microgravity and 1 g on Earth were examined to assess the role of gravity on cellulose microfibril (CMF) organization and secondary wall thickening patterns. Using a quick freeze/deep etch technique, this revealed that the cell wall CMFs of the space-grown wheat maintained the same organization as their 1 g-grown counterparts. That is, in all instances, CMFs were randomly interwoven with each other in the outermost layers (farthest removed from the plasma membrane), and parallel to each other within the individual strata immediately adjacent to the plasma membranes. The CMF angle in the innermost stratum relative to the immediately adjacent stratum was ca 80 degrees in both the space and Earth-grown plants. Second, all plants grown in microgravity had roots that grew downwards into the agar; they did not display "wandering" and upward growth as previously reported by others. Third, the space-grown wheat also developed normal protoxylem and metaxylem vessel elements with secondary thickening patterns ranging from spiral to regular pit to reticulate thickenings. Fourthly, both the space- and Earth-grown plants were essentially of the same size and height, and their lignin analyses revealed no substantial differences in their amounts and composition regardless of the gravitational

Exercise and training effects on gastric emptying of carbohydrate beverages.

PubMed

Rehrer, N J; Beckers, E; Brouns, F; Hoor ten, F; Saris, W H

1989-10-01

Carbohydrate containing drinks are commonly consumed as an ergogenic aid during endurance sports activities. The efficacy of a given drink is limited by the rate of absorption, which is in turn limited by gastric emptying. A myriad of factors influence gastric emptying. The influence of several of these factors (training status, exercise intensity, and carbohydrate composition) was investigated by repeated experiments using a nasogastric tube and a modification of the technique of George. A group of well-trained bicyclists and a group of untrained subjects performed similar experiments. Three different carbohydrate containing drinks (15 g.100 ml-1 glucose (G), 15 g.100 ml-1 maltodextrin plus 3 g.100 ml-1 fructose (MD), 7 g.100 ml-1 sucrose (I] and artificially sweetened water were compared during rest and 50 and 70% Wmax bicycling. Experimental design was crossover. There was a trend for the carbohydrate drinks to empty initially more slowly under the influence of exercise. Differences in drink volume remaining in the stomach were significant (P less than 0.05), with I at 10 min (70%, mean = 48.9%; rest, mean = 30.5%) and at 20 min (70%, mean = 28.9%; rest, mean = 23.8%) and with MD at 10 min (70%, mean = 71.1%; rest, mean = 55.9%). A similar trend was also seen with 50% Wmax exercise; however, this trend was only significant with MD at 10 min (50%, mean = 72.1%; rest, mean = 55.9%). Drink composition was a much stronger inhibitor of gastric emptying. However, all drinks emptied exponentially with fast-phase initial emptying rates. No differences in gastric emptying or secretion were observed between trained and untrained subjects.

Carbohydrate-Restriction with High-Intensity Interval Training: An Optimal Combination for Treating Metabolic Diseases?

PubMed

Francois, Monique E; Gillen, Jenna B; Little, Jonathan P

2017-01-01

Lifestyle interventions incorporating both diet and exercise strategies remain cornerstone therapies for treating metabolic disease. Carbohydrate-restriction and high-intensity interval training (HIIT) have independently been shown to improve cardiovascular and metabolic health. Carbohydrate-restriction reduces postprandial hyperglycemia, thereby limiting potential deleterious metabolic and cardiovascular consequences of excessive glucose excursions. Additionally, carbohydrate-restriction has been shown to improve body composition and blood lipids. The benefits of exercise for improving insulin sensitivity are well known. In this regard, HIIT has been shown to rapidly improve glucose control, endothelial function, and cardiorespiratory fitness. Here, we report the available evidence for each strategy and speculate that the combination of carbohydrate-restriction and HIIT will synergistically maximize the benefits of both approaches. We hypothesize that this lifestyle strategy represents an optimal intervention to treat metabolic disease; however, further research is warranted in order to harness the potential benefits of carbohydrate-restriction and HIIT for improving cardiometabolic health.

Carbohydrate-Restriction with High-Intensity Interval Training: An Optimal Combination for Treating Metabolic Diseases?

PubMed Central

Francois, Monique E.; Gillen, Jenna B.; Little, Jonathan P.

2017-01-01

Lifestyle interventions incorporating both diet and exercise strategies remain cornerstone therapies for treating metabolic disease. Carbohydrate-restriction and high-intensity interval training (HIIT) have independently been shown to improve cardiovascular and metabolic health. Carbohydrate-restriction reduces postprandial hyperglycemia, thereby limiting potential deleterious metabolic and cardiovascular consequences of excessive glucose excursions. Additionally, carbohydrate-restriction has been shown to improve body composition and blood lipids. The benefits of exercise for improving insulin sensitivity are well known. In this regard, HIIT has been shown to rapidly improve glucose control, endothelial function, and cardiorespiratory fitness. Here, we report the available evidence for each strategy and speculate that the combination of carbohydrate-restriction and HIIT will synergistically maximize the benefits of both approaches. We hypothesize that this lifestyle strategy represents an optimal intervention to treat metabolic disease; however, further research is warranted in order to harness the potential benefits of carbohydrate-restriction and HIIT for improving cardiometabolic health. PMID:29075629

Food-derived carbohydrates--structural complexity and functional diversity.

PubMed

Tharanathan, Rudrapatnam N

2002-01-01

Carbohydrates are biomolecules abundantly available in nature. They are found in bewildering types ranging from simple sugars through oligo- and polysaccharides to glycoconjugates and saccharide complexes, each exhibiting characteristic bio-physiological and/or nutritional functions both in in vivo and in vitro systems. For example, their presence or inclusion in food dictates the texture (body) and gives desirable customer appeal (satisfaction), or their inclusion in the diet offers beneficial effects of great therapeutic value. Thus, carbohydrates are integrally involved in a multitude of biological functions such as regulation of the immune system, cellular signaling (communication), cell malignancy, antiinfection responses, host-pathogen interactions, etc. If starch is considered the major energy storage carbohydrate, the gums/mucilages and other non-starch carbohydrates are of structural significance. The most investigated properties of starch are its gelatinization and melting behavior, especially during food processing. This has led to the development of the food polymer science approach, which has enabled a new interpretive and experimental frame work for the study of the plasticizing influence of simple molecules such as water, sugars, etc. on food systems that are kinetically constrained. Starch, although considered fully digestible, has been challenged, and starch is found to be partly indigestible in the GI tract of humans. This fraction of starch-resisting digestion in vivo is known as resistant starch (RS). The latter, due to its excellent fermentative capacity in the gut, especially yielding butyric acid is considered a new tool for the creation of fiber-rich foods, which are of nutraceutical importance. By a careful control of the processing conditions the content of RS, a man-made fiber, can be increased to as high as 30%. Arabinoxylans are the major endospermic cell wall polysaccharides of cereals. In wheat they are found complexed with ferulic

Degradation of carbohydrates and lignins in buried woods

USGS Publications Warehouse

Hedges, J.I.; Cowie, G.L.; Ertel, J.R.; James, Barbour R.; Hatcher, P.G.

1985-01-01

Spruce, alder, and oak woods deposited in coastal sediments were characterized versus their modern counterparts by quantification of individual neutral sugars and lignin-derived phenols as well as by scanning electron microscopy, 13C NMR, and elemental analysis. The buried spruce wood from a 2500 yr old deposit was unaltered whereas an alder wood from the same horizon and an oak wood from an open ocean sediment were profoundly degraded. Individual sugar and lignin phenol analyses indicate that at least 90 and 98 wt% of the initial total polysaccharides in the buried alder and oak woods, respectively, have been degraded along with 15-25 wt% of the lignin. At least 75% of the degraded biopolymer has been physically lost from these samples. This evidence is supported by the SEM, 13C NMR and elemental analyses, all of which indicate selective loss of the carbohydrate moiety. The following order of stability was observed for the major biochemical constituents of both buried hardwoods: vanillyl and p-hydroxyl lignin structural units > syringyl lignin structural units > pectin > ??-cellulose > hemicellulose. This sequence can be explained by selective preservation of the compound middle lamella regions of the wood cell walls. The magnitude and selectivity of the indicated diagenetic reactions are sufficient to cause major changes in the chemical compositions of wood-rich sedimentary organic mixtures and to provide a potentially large in situ nutrient source. ?? 1985.

Nanocatalyst shape and composition during nucleation of single-walled carbon nanotubes

DOE PAGES

Gomez-Ballesteros, Jose L.; Burgos, Juan C.; Lin, Pin Ann; ...

2015-12-07

The dynamic evolution of nanocatalyst particle shape and carbon composition during the initial stages of single-walled carbon nanotube growth by chemical vapor deposition synthesis is investigated. Classical reactive and ab initio molecular dynamics simulations are used, along with environmental transmission electron microscope video imaging analyses. A clear migration of carbon is detected from the nanocatalyst/substrate interface, leading to a carbon gradient showing enrichment of the nanocatalyst layers in the immediate vicinity of the contact layer. However, as the metal nanocatalyst particle becomes saturated with carbon, a dynamic equilibrium is established, with carbon precipitating on the surface and nucleating a carbonmore » cap that is the precursor of nanotube growth. A carbon composition profile decreasing towards the nanoparticle top is clearly revealed by the computational and experimental results that show a negligible amount of carbon in the nanoparticle region in contact with the nucleating cap. The carbon composition profile inside the nanoparticle is accompanied by a well-defined shape evolution of the nanocatalyst driven by the various opposing forces acting upon it both from the substrate and from the nascent carbon nanostructure. In conclusion, this new understanding suggests that tuning the nanoparticle/substrate interaction would provide unique ways of controlling the nanotube synthesis.« less

Carbohydrates--the renewable raw materials of high biotechnological value.

PubMed

Ramesh, Honnavally P F; Tharanathan, Rudrapatnam N

2003-01-01

Carbohydrates are the potential biomolecules derived from nature. Their molecular diversity has led to a bewildering variety of species, structures and characteristics all performing a large array of functions of great significance. Biologically they are vital as message (immunological) carriers, physiologically they are useful as energy (nutritional) reserves, and technologically they are needed for altering the texture and consistency (functional) of foods. Recent advances in glycobiology have opened up a new understanding of the role of sugars in biology and medicine. Noncellulosic beta-(1-3)-linked D-glucans, a group of polysaccharides found as constituents of fungi, algae, and higher plants, exhibit many interesting properties, depending on their molecular conformation. They are excellent 'biological response modifiers' and show significant immunomodulatory activities. They elicit a variety of host defense biological responses, for example, potent antitumor activity. On the other hand, the mixed-linkage ((1-3/1-4)-beta-linked) glucans are important constituents of cereal cell walls, where they perform properties of physiological importance, such as water holding capacity, porosity, and plasticity, which are useful at different stages of growth/development of plants. Of late, carbohydrate-based therapeutics are becoming the promise against many chronic diseases of today and tomorrow. Some of the characteristic features, structural attributes, functional significance, and applications of a selected few carbohydrate species are the subject matter of this review.

Production and flux of carbohydrate species in the Gulf of Mexico

NASA Astrophysics Data System (ADS)

Hung, Chin-Chang; Guo, Laodong; Schultz, Gary E.; Pinckney, James L.; Santschi, Peter H.

2003-06-01

Carbohydrates are an important organic compound class in seawater and play an active role in the biogeochemical cycling of organic carbon and trace elements in the ocean, but are poorly characterized. To better understand the sources and role of carbohydrate species in marine environments, the concentrations and fluxes of particulate carbohydrates (CHO), total acid polysaccharides (APS), uronic acids (URA), phytoplankton composition and bacterial production were measured in the Gulf of Mexico in 2000 and 2001. A strong positive correlation between APS concentration and cyanobacteria abundance was found in 2000. In 2001, prymnesiophyte abundance correlated well with both concentrations of APS and URA. Bacterial production data, measured simultaneously in 2001, showed significant positive relationships with particulate organic carbon (POC), CHO, APS and URA concentrations, respectively. The average fluxes out of the euphotic zone of CHO, APS and URA in 2000 were 8.1, 1.3, and 0.7 mg C m-2 d-1, respectively. In 2001, the average fluxes of CHO, APS and URA were about 3 times higher than those in 2000, which was a time of lower nutrient concentrations, indicating that the fluxes of carbohydrate species are related to the nutrient status and phytoplankton composition. The results suggest that APS in the upper water column can be produced by cyanobacteria, prymnesiophytes, and heterotrophic bacteria. Most importantly, our data indicate that APS and CHO compounds are more resistant to biological degradation than other organic compounds, suggesting that the role of CHO compounds in carbon cycling in the ocean is more complex than previously thought.

Arabidopsis leucine-rich repeat extensin (LRX) proteins modify cell wall composition and influence plant growth.

PubMed

Draeger, Christian; Ndinyanka Fabrice, Tohnyui; Gineau, Emilie; Mouille, Grégory; Kuhn, Benjamin M; Moller, Isabel; Abdou, Marie-Therese; Frey, Beat; Pauly, Markus; Bacic, Antony; Ringli, Christoph

2015-06-24

Leucine-rich repeat extensins (LRXs) are extracellular proteins consisting of an N-terminal leucine-rich repeat (LRR) domain and a C-terminal extensin domain containing the typical features of this class of structural hydroxyproline-rich glycoproteins (HRGPs). The LRR domain is likely to bind an interaction partner, whereas the extensin domain has an anchoring function to insolubilize the protein in the cell wall. Based on the analysis of the root hair-expressed LRX1 and LRX2 of Arabidopsis thaliana, LRX proteins are important for cell wall development. The importance of LRX proteins in non-root hair cells and on the structural changes induced by mutations in LRX genes remains elusive. The LRX gene family of Arabidopsis consists of eleven members, of which LRX3, LRX4, and LRX5 are expressed in aerial organs, such as leaves and stem. The importance of these LRX genes for plant development and particularly cell wall formation was investigated. Synergistic effects of mutations with gradually more severe growth retardation phenotypes in double and triple mutants suggest a similar function of the three genes. Analysis of cell wall composition revealed a number of changes to cell wall polysaccharides in the mutants. LRX3, LRX4, and LRX5, and most likely LRX proteins in general, are important for cell wall development. Due to the complexity of changes in cell wall structures in the lrx mutants, the exact function of LRX proteins remains to be determined. The increasingly strong growth-defect phenotypes in double and triple mutants suggests that the LRX proteins have similar functions and that they are important for proper plant development.

The effects of whey protein with or without carbohydrates on resistance training adaptations.

PubMed

Hulmi, Juha J; Laakso, Mia; Mero, Antti A; Häkkinen, Keijo; Ahtiainen, Juha P; Peltonen, Heikki

2015-01-01

Nutrition intake in the context of a resistance training (RT) bout may affect body composition and muscle strength. However, the individual and combined effects of whey protein and carbohydrates on long-term resistance training adaptations are poorly understood. A four-week preparatory RT period was conducted in previously untrained males to standardize the training background of the subjects. Thereafter, the subjects were randomized into three groups: 30 g of whey proteins (n = 22), isocaloric carbohydrates (maltodextrin, n = 21), or protein + carbohydrates (n = 25). Within these groups, the subjects were further randomized into two whole-body 12-week RT regimens aiming either for muscle hypertrophy and maximal strength or muscle strength, hypertrophy and power. The post-exercise drink was always ingested immediately after the exercise bout, 2-3 times per week depending on the training period. Body composition (by DXA), quadriceps femoris muscle cross-sectional area (by panoramic ultrasound), maximal strength (by dynamic and isometric leg press) and serum lipids as basic markers of cardiovascular health, were analysed before and after the intervention. Twelve-week RT led to increased fat-free mass, muscle size and strength independent of post-exercise nutrient intake (P < 0.05). However, the whey protein group reduced more total and abdominal area fat when compared to the carbohydrate group independent of the type of RT (P < 0.05). Thus, a larger relative increase (per kg bodyweight) in fat-free mass was observed in the protein vs. carbohydrate group (P < 0.05) without significant differences to the combined group. No systematic effects of the interventions were found for serum lipids. The RT type did not have an effect on the adaptations in response to different supplementation paradigms. Post-exercise supplementation with whey proteins when compared to carbohydrates or combination of proteins and carbohydrates did not have a major

The N-Terminal Domain of the Flo1 Flocculation Protein from Saccharomyces cerevisiae Binds Specifically to Mannose Carbohydrates ▿

PubMed Central

Goossens, Katty V. Y.; Stassen, Catherine; Stals, Ingeborg; Donohue, Dagmara S.; Devreese, Bart; De Greve, Henri; Willaert, Ronnie G.

2011-01-01

Saccharomyces cerevisiae cells possess a remarkable capacity to adhere to other yeast cells, which is called flocculation. Flocculation is defined as the phenomenon wherein yeast cells adhere in clumps and sediment rapidly from the medium in which they are suspended. These cell-cell interactions are mediated by a class of specific cell wall proteins, called flocculins, that stick out of the cell walls of flocculent cells. The N-terminal part of the three-domain protein is responsible for carbohydrate binding. We studied the N-terminal domain of the Flo1 protein (N-Flo1p), which is the most important flocculin responsible for flocculation of yeast cells. It was shown that this domain is both O and N glycosylated and is structurally composed mainly of β-sheets. The binding of N-Flo1p to d-mannose, α-methyl-d-mannoside, various dimannoses, and mannan confirmed that the N-terminal domain of Flo1p is indeed responsible for the sugar-binding activity of the protein. Moreover, fluorescence spectroscopy data suggest that N-Flo1p contains two mannose carbohydrate binding sites with different affinities. The carbohydrate dissociation constants show that the affinity of N-Flo1p for mono- and dimannoses is in the millimolar range for the binding site with low affinity and in the micromolar range for the binding site with high affinity. The high-affinity binding site has a higher affinity for low-molecular-weight (low-MW) mannose carbohydrates and no affinity for mannan. However, mannan as well as low-MW mannose carbohydrates can bind to the low-affinity binding site. These results extend the cellular flocculation model on the molecular level. PMID:21076009

An Applied Method for Predicting the Load-Carrying Capacity in Compression of Thin-Wall Composite Structures with Impact Damage

NASA Astrophysics Data System (ADS)

Mitrofanov, O.; Pavelko, I.; Varickis, S.; Vagele, A.

2018-03-01

The necessity for considering both strength criteria and postbuckling effects in calculating the load-carrying capacity in compression of thin-wall composite structures with impact damage is substantiated. An original applied method ensuring solution of these problems with an accuracy sufficient for practical design tasks is developed. The main advantage of the method is its applicability in terms of computing resources and the set of initial data required. The results of application of the method to solution of the problem of compression of fragments of thin-wall honeycomb panel damaged by impacts of various energies are presented. After a comparison of calculation results with experimental data, a working algorithm for calculating the reduction in the load-carrying capacity of a composite object with impact damage is adopted.

(1)H NMR spectroscopy for profiling complex carbohydrate mixtures in non-fractionated beer.

PubMed

Petersen, Bent O; Nilsson, Mathias; Bøjstrup, Marie; Hindsgaul, Ole; Meier, Sebastian

2014-05-01

A plethora of biological and biotechnological processes involve the enzymatic remodelling of carbohydrates in complex mixtures whose compositions affect both the processes and products. In the current study, we employed high-resolution (1)H NMR spectroscopy for the analysis of cereal-derived carbohydrate mixtures as exemplified on six beer samples of different styles. Structural assignments of more than 50 carbohydrate moieties were obtained using (1)H1-(1)H2 groups as structural reporters. Spectroscopically resolved carbohydrates include more than ''20 different'' small carbohydrates with more than 38 isomeric forms in addition to cereal polysaccharide fragments with suspected organoleptic and prebiotic function. Structural motifs at the cleavage sites of starch, β-glucan and arabinoxylan fragments were identified, showing different extent and specificity of enzymatic polysaccharide cleavage during the production of different beer samples. Diffusion ordered spectroscopy supplied independent size information for the characterisation and identification of polysaccharide fragments, indicating the presence especially of high molecular weight arabinoxylan fragments in the final beer. Copyright © 2013 Elsevier Ltd. All rights reserved.

Structural analysis of N-linked carbohydrate chains of funnel web spider (Agelenopsis aperta) venom peptide isomerase.

PubMed

Shikata, Y; Ohe, H; Mano, N; Kuwada, M; Asakawa, N

1998-06-01

The structure of the N-linked carbohydrate chains of peptide isomerase from the venom of the funnel web spider (Agelenopsis aperta) has been analyzed. Carbohydrates were released from peptide isomerase by hydrazinolysis and reductively aminated with 2-aminopyridine. The fluorescent derivatives were purified by phenol/chloroform extraction, followed by size-exclusion HPLC. The structure of the purified pyridylamino (PA-) carbohydrate chains were analyzed by a combination of two-dimensional HPLC mapping, sugar composition analysis, sequential exoglycosidase digestions, and mass spectrometry. The peptide isomerase contains six kinds of N-linked carbohydrate chains of truncated high-mannose type, with a fucose alpha 1-6 linked to the reducing N-acetylglucosamine in approximately 80% of them.

Participation of Candida albicans Transcription Factor RLM1 in Cell Wall Biogenesis and Virulence

PubMed Central

Delgado-Silva, Yolanda; Vaz, Catarina; Carvalho-Pereira, Joana; Carneiro, Catarina; Nogueira, Eugénia; Correia, Alexandra; Carreto, Laura; Silva, Sónia; Faustino, Augusto; Pais, Célia; Oliveira, Rui; Sampaio, Paula

2014-01-01

Candida albicans cell wall is important for growth and interaction with the environment. RLM1 is one of the putative transcription factors involved in the cell wall integrity pathway, which plays an important role in the maintenance of the cell wall integrity. In this work we investigated the involvement of RLM1 in the cell wall biogenesis and in virulence. Newly constructed C. albicans Δ/Δrlm1 mutants showed typical cell wall weakening phenotypes, such as hypersensitivity to Congo Red, Calcofluor White, and caspofungin (phenotype reverted in the presence of sorbitol), confirming the involvement of RLM1 in the cell wall integrity. Additionally, the cell wall of C. albicans Δ/Δrlm1 showed a significant increase in chitin (213%) and reduction in mannans (60%), in comparison with the wild-type, results that are consistent with cell wall remodelling. Microarray analysis in the absence of any stress showed that deletion of RLM1 in C. albicans significantly down-regulated genes involved in carbohydrate catabolism such as DAK2, GLK4, NHT1 and TPS1, up-regulated genes involved in the utilization of alternative carbon sources, like AGP2, SOU1, SAP6, CIT1 or GAL4, and genes involved in cell adhesion like ECE1, ALS1, ALS3, HWP1 or RBT1. In agreement with the microarray results adhesion assays showed an increased amount of adhering cells and total biomass in the mutant strain, in comparison with the wild-type. C. albicans mutant Δ/Δrlm1 strain was also found to be less virulent than the wild-type and complemented strains in the murine model of disseminated candidiasis. Overall, we showed that in the absence of RLM1 the modifications in the cell wall composition alter yeast interaction with the environment, with consequences in adhesion ability and virulence. The gene expression findings suggest that this gene participates in the cell wall biogenesis, with the mutant rearranging its metabolic pathways to allow the use of alternative carbon sources. PMID:24466000

Dietary intakes, attitudes toward carbohydrates of postmenopausal women following low carbohydrate diets.

PubMed

Winham, Donna M; Collins, Courtney B; Hutchins, Andrea M

2009-01-01

Middle-aged women have the highest levels of obesity and comprise the largest group of dieters. Few investigators have examined how women apply weight-loss diet principles in an unsupervised setting. Dietary intakes and attitudes toward carbohydrates were examined in women who were self-reported low carbohydrate dieters (SRLCDs); these intakes and attitudes were compared with those of women who were following their normal diet (non-dieters [NDs]). A convenience sample of 29 postmenopausal women aged 45 to 65 was recruited. Data were obtained by interview, questionnaire, and direct anthropometric measurement. Descriptive statistics, chi-square analysis, and analysis of variance were used to compare groups. Although total energy and protein intakes were similar, SRLCDs consumed significantly more fat and less carbohydrate (expressed as a percentage of total energy) and more cholesterol and less fibre than did NDs. Both groups had unfavourable attitudes toward carbohydrates. The SRLCDs ate more fat than recommended. Women who are considering following a low carbohydrate diet need to know the nutritional risks of unbalanced self-designed low carbohydrate diets. Negative attitudes toward carbohydrates were not confined to dieters. Nutrition education is necessary to help consumers understand basic nutrition principles and to be more skeptical of fad diets.

Digestion and Absorption of Carbohydrates

USDA-ARS?s Scientific Manuscript database

Carbohydrates are the major dietary sources of energy for humans. While most dietary carbohydrates are derived from multiple botanical sources, lactose and trehalose are the only animal-derived carbohydrates. Digestion of starch, the carbohydrate most abundantly consumed by humans, depends on the c...

The carbohydrate maintenance properties of an experimental sports drink.

PubMed Central

White, J. A.; Ford, M. A.

1984-01-01

The effects of an experimental sports drink (Q) were compared with a commercial sports drink (D) of proven ergogenic efficacy. Seven highly trained subjects performed two hours of cycle ergometry exercise at approximately 65% maximal aerobic power (VO2 max) while receiving levels of Q and D in quantities designed to supply approximately 28% of the total energy requirement of the exercise task. Both Q and D formulations were supplied at 15 minute intervals at 16 degrees C, in volumes required to provide equivalent carbohydrate loads from two products of differing concentrations and compositions. Q was equally as effective as D in terms of the maintenance of plasma glucose concentrations during exercise, while selected physiological indices of work performance favoured Q. However, the time course of plasma glucose concentration changes during and after exercise indicated a trend towards more rapid uptake and assimilation of carbohydrate in the case of Q. The findings suggest that Q may provide a more readily available carbohydrate source during exercise and may enhance work performance through its ergogenic properties. Images p64-a p64-b PMID:6466932

Meal composition and plasma amino acid ratios: Effect of various proteins or carbohydrates, and of various protein concentrations

NASA Technical Reports Server (NTRS)

Yokogoshi, Hidehiko; Wurtman, Richard J.

1986-01-01

The effects of meals containing various proteins and carbohydrates, and of those containing various proportions of protein (0 percent to 20 percent of a meal, by weight) or of carbohydrate (0 percent to 75 percent), on plasma levels of certain large neutral amino acids (LNAA) in rats previously fasted for 19 hours were examined. Also the plasma tryptophan ratios (the ratio of the plasma trytophan concentration to the summed concentrations of the other large neutral amino acids) and other plasma amino acid ratios were calculated. (The plasma tryptophan ratio has been shown to determine brain tryptophan levels and, thereby, to affect the synthesis and release of the neurotransmitter serotonin). A meal containing 70 percent to 75 percent of an insulin-secreting carbohydrate (dextrose or dextrin) increased plasma insulin levels and the tryptophan ratio; those containing 0 percent or 25 percent carbohydrate failed to do so. Addition of as little as 5 percent casein to a 70 percent carbohydrate meal fully blocked the increase in the plasma tryptophan ratio without affecting the secretion of insulin - probably by contributing much larger quantities of the other LNAA than of tryptophan to the blood. Dietary proteins differed in their ability to suppress the carbohydrate-induced rise in the plasma tryptophan ratio. Addition of 10 percent casein, peanut meal, or gelatin fully blocked this increase, but lactalbumin failed to do so, and egg white did so only partially. (Consumption of the 10 percent gelatin meal also produced a major reduction in the plasma tyrosine ratio, and may thereby have affected brain tyrosine levels and catecholamine synthesis.) These observations suggest that serotonin-releasing neurons in brains of fasted rats are capable of distinguishing (by their metabolic effects) between meals poor in protein but rich in carbohydrates that elicit insulin secretion, and all other meals. The changes in brain serotonin caused by carbohydrate-rich, protein

Composite Behavior of Insulated Concrete Sandwich Wall Panels Subjected to Wind Pressure and Suction.

PubMed

Choi, Insub; Kim, JunHee; Kim, Ho-Ryong

2015-03-19

A full-scale experimental test was conducted to analyze the composite behavior of insulated concrete sandwich wall panels (ICSWPs) subjected to wind pressure and suction. The experimental program was composed of three groups of ICSWP specimens, each with a different type of insulation and number of glass-fiber-reinforced polymer (GFRP) shear grids. The degree of composite action of each specimen was analyzed according to the load direction, type of the insulation, and number of GFRP shear grids by comparing the theoretical and experimental values. The failure modes of the ICSWPs were compared to investigate the effect of bonds according to the load direction and type of insulation. Bonds based on insulation absorptiveness were effective to result in the composite behavior of ICSWP under positive loading tests only, while bonds based on insulation surface roughness were effective under both positive and negative loading tests. Therefore, the composite behavior based on surface roughness can be applied to the calculation of the design strength of ICSWPs with continuous GFRP shear connectors.

Composite Behavior of Insulated Concrete Sandwich Wall Panels Subjected to Wind Pressure and Suction

PubMed Central

Choi, Insub; Kim, JunHee; Kim, Ho-Ryong

2015-01-01

A full-scale experimental test was conducted to analyze the composite behavior of insulated concrete sandwich wall panels (ICSWPs) subjected to wind pressure and suction. The experimental program was composed of three groups of ICSWP specimens, each with a different type of insulation and number of glass-fiber-reinforced polymer (GFRP) shear grids. The degree of composite action of each specimen was analyzed according to the load direction, type of the insulation, and number of GFRP shear grids by comparing the theoretical and experimental values. The failure modes of the ICSWPs were compared to investigate the effect of bonds according to the load direction and type of insulation. Bonds based on insulation absorptiveness were effective to result in the composite behavior of ICSWP under positive loading tests only, while bonds based on insulation surface roughness were effective under both positive and negative loading tests. Therefore, the composite behavior based on surface roughness can be applied to the calculation of the design strength of ICSWPs with continuous GFRP shear connectors. PMID:28788001

Molecular simulations of carbohydrates and protein-carbohydrate interactions: motivation, issues and prospects.

PubMed

Fadda, Elisa; Woods, Robert J

2010-08-01

The characterization of the 3D structure of oligosaccharides, their conjugates and analogs is particularly challenging for traditional experimental methods. Molecular simulation methods provide a basis for interpreting sparse experimental data and for independently predicting conformational and dynamic properties of glycans. Here, we summarize and analyze the issues associated with modeling carbohydrates, with a detailed discussion of four of the most recently developed carbohydrate force fields, reviewed in terms of applicability to natural glycans, carbohydrate-protein complexes and the emerging area of glycomimetic drugs. In addition, we discuss prospectives and new applications of carbohydrate modeling in drug discovery.

Effects of Low-Carbohydrate and Low-Fat Diets

PubMed Central

Bazzano, Lydia A.; Hu, Tian; Reynolds, Kristi; Yao, Lu; Bunol, Calynn; Liu, Yanxi; Chen, Chung-Shiuan; Klag, Michael J.; Whelton, Paul K.; He, Jiang

2015-01-01

Background Low-carbohydrate diets are popular for weight loss, but their cardiovascular effects have not been well-studied, particularly in diverse populations. Objective To examine the effects of a low-carbohydrate diet compared with a low-fat diet on body weight and cardiovascular risk factors. Design A randomized, parallel-group trial. (ClinicalTrials.gov: NCT00609271) Setting A large academic medical center. Participants 148 men and women without clinical cardiovascular disease and diabetes. Intervention A low-carbohydrate (<40 g/d) or low-fat diet (<30% fat; <7% saturated fat). Both groups received dietary counseling at regular intervals throughout the trial. Measurements Data on weight, cardiovascular risk factors, and dietary composition were collected at 0, 3, 6, and 12 months. Results Sixty participants (82%) in the low-fat group and 59 (79%) in the low-carbohydrate group completed the intervention. At 12 months, participants on the low-carbohydrate diet had greater decreases in weight (mean difference in change, −3.5 kg [95% CI, −5.6 to −1.4 kg]; P < 0.001), fat mass (mean difference in change, −1.5% [CI, −2.6% to −0.4%]; P = 0.011), ratio of total to high-density lipoprotein (HDL) cholesterol (mean difference in change, −0.44 [CI, −0.71 to −0.16]; P = 0.002), and triglyceride level (mean difference in change, −0.16 mmol/L [−14.1 mg/dL] [CI, −0.31 to −0.01 mmol/L {−27.4 to −0.8 mg/dL}]; P = 0.038) and greater increases in HDL cholesterol level (mean difference in change, 0.18 mmol/L [7.0 mg/dL] [CI, 0.08 to 0.28 mmol/L {3.0 to 11.0 mg/dL}]; P< 0.001) than those on the low-fat diet. Limitation Lack of clinical cardiovascular disease end points. Conclusion The low-carbohydrate diet was more effective for weight loss and cardiovascular risk factor reduction than the low-fat diet. Restricting carbohydrate may be an option for persons seeking to lose weight and reduce cardiovascular risk factors. Primary Funding Source National

Carbohydrate Loading.

ERIC Educational Resources Information Center

Csernus, Marilyn

Carbohydrate loading is a frequently used technique to improve performance by altering an athlete's diet. The objective is to increase glycogen stored in muscles for use in prolonged strenuous exercise. For two to three days, the athlete consumes a diet that is low in carbohydrates and high in fat and protein while continuing to exercise and…

Distribution of structural carbohydrates in corn plants across the southeastern USA

USDA-ARS?s Scientific Manuscript database

Quantifying lignin and carbohydrate composition of corn (Zea mays L.) is important to support the emerging cellulosic biofuels industry. Therefore, field studies with 0 or 100% stover removal were established in Alabama and South Carolina as part of the Sun Grant Regional Partnership Corn Stover Pro...

Following the compositional changes of fresh grape skin cell walls during the fermentation process in the presence and absence of maceration enzymes.

PubMed

Zietsman, Anscha J J; Moore, John P; Fangel, Jonatan U; Willats, William G T; Trygg, Johan; Vivier, Melané A

2015-03-18

Cell wall profiling technologies were used to follow compositional changes that occurred in the skins of grape berries (from two different ripeness levels) during fermentation and enzyme maceration. Multivariate data analysis showed that the fermentation process yielded cell walls enriched in hemicellulose components because pectin was solubilized (and removed) with a reduction as well as exposure of cell wall proteins usually embedded within the cell wall structure. The addition of enzymes caused even more depectination, and the enzymes unravelled the cell walls enabling better access to, and extraction of, all cell wall polymers. Overripe grapes had cell walls that were extensively hydrolyzed and depolymerized, probably by natural grape-tissue-ripening enzymes, and this enhanced the impact that the maceration enzymes had on the cell wall monosaccharide profile. The combination of the techniques that were used is an effective direct measurement of the hydrolysis actions of maceration enzymes on the cell walls of grape berry skin.

Comparative Studies on Al-Based Composite Powder Reinforced with Nano Garnet and Multi-wall Carbon Nanotubes

NASA Astrophysics Data System (ADS)

Basariya, M. Raviathul; Srivastava, V. C.; Mukhopadhyay, N. K.

2015-11-01

Effect of mechanical alloying/milling on microstructural evolution and hardness variations of garnet and multi-walled carbon nanotubes (MWCNTs)-reinforced Al-Mg-Si alloy (EN AW6082) composites are investigated. Structural and morphological studies revealed that the composite powders prepared by milling display a more homogenous distribution of the reinforcing particles. Improved nanoindentation hardness viz., 4.24 and 5.90 GPa are achieved for EN AW6082/Garnet and EN AW6082/MWCNTs composites, respectively, and it is attributed to severe deformation of the aluminum alloy powders and embedding of the harder reinforcement particles uniformly into the aluminum alloy matrix. However, enhancement in case of MWCNTs-reinforced composite makes apparent the effect of its nanosized uniform dispersion in the matrix, thereby resisting the plastic deformation at lower stress and increased dislocation density evolved during high-energy ball milling. The results of the present study indicate that carbon nanotubes and garnet can be effectively used as reinforcements for Al-based composites.

Significance of wall structure, macromolecular composition, and surface polymers to the survival and transport of Cryptosporidium parvum Oocysts

USDA-ARS?s Scientific Manuscript database

The structure and composition of the oocyst wall are primary factors determining the survival of Cryptosporidium parvum oocysts outside the host. An external polymer matrix (glycocalyx) may mediate interactions with environmental surfaces and, thus, affect the transport of oocysts in water, soil, an...

Metabolic labelling of the carbohydrate core in bacterial peptidoglycan and its applications

PubMed Central

Liang, Hai; DeMeester, Kristen E.; Hou, Ching-Wen; Parent, Michelle A.; Caplan, Jeffrey L.; Grimes, Catherine L.

2017-01-01

Bacterial cells are surrounded by a polymer known as peptidoglycan (PG), which protects the cell from changes in osmotic pressure and small molecule insults. A component of this material, N-acetyl-muramic acid (NAM), serves as a core structural element for innate immune recognition of PG fragments. We report the synthesis of modifiable NAM carbohydrate derivatives and the installation of these building blocks into the backbone of Gram-positive and Gram-negative bacterial PG utilizing metabolic cell wall recycling and biosynthetic machineries. Whole cells are labelled via click chemistry and visualized using super-resolution microscopy, revealing higher resolution PG structural details and allowing the cell wall biosynthesis, as well as its destruction in immune cells, to be tracked. This study will assist in the future identification of mechanisms that the immune system uses to recognize bacteria, glean information about fundamental cell wall architecture and aid in the design of novel antibiotics. PMID:28425464

Decoration of multi-walled carbon nanotubes by polymer wrapping and its application in MWCNT/polyethylene composites.

PubMed

Hsiao, An-En; Tsai, Shu-Ya; Hsu, Mei-Wen; Chang, Shinn-Jen

2012-05-06

We dispersed the non-covalent functionalization of multi-walled carbon nanotubes (CNTs) with a polymer dispersant and obtained a powder of polymer-wrapped CNTs. The UV-vis absorption spectrum was used to investigate the optimal weight ratio of the CNTs and polymer dispersant. The powder of polymer-wrapped CNTs had improved the drawbacks of CNTs of being lightweight and difficult to process, and it can re-disperse in a solvent. Then, we blended the polymer-wrapped CNTs and polyethylene (PE) by melt-mixing and produced a conductive masterbatch and CNT/PE composites. The polymer-wrapped CNTs showed lower surface resistivity in composites than the raw CNTs. The scanning electron microscopy images also showed that the polymer-wrapped CNTs can disperse well in composites than the raw CNTs.

Comparison of the effects of 52 weeks weight loss with either a high-protein or high-carbohydrate diet on body composition and cardiometabolic risk factors in overweight and obese males.

PubMed

Wycherley, T P; Brinkworth, G D; Clifton, P M; Noakes, M

2012-08-13

A high-protein (HP), low-fat weight-loss diet may be advantageous for improving cardiometabolic health outcomes and body composition. To date, only limited research has been conducted in male participants. To evaluate the medium to long-term effects of two, low-fat, hypocaloric diets differing in carbohydrate:protein ratio on body composition and cardiometabolic health outcomes in overweight and obese males. One hundred and twenty males (age 50.8±9.3 (s.d.) years, body mass index 33.0±3.9 kg m(-2)) were randomly assigned and consumed a low-fat, isocaloric, energy-restricted diet (7 MJ per day) with either HP (protein:carbohydrate:fat %energy, 35:40:25) or high carbohydrate (HC; 17:58:25). Body weight, body composition and cardiometabolic risk factors were assessed at baseline and after 12 and 52 weeks. Sixty-eight participants completed the study (HP, n=33; HC, n=35). At 1 year both the groups experienced similar reductions in body weight (HP, -12.3±8.0 kg (-12%); HC, -10.9±8.6 kg (-11%); P=0.83 time × group interaction) and fat mass (-9.9±6.0 kg (-27%) vs -7.3±5.8 kg (-22%); P=0.11). Participants who consumed the HP diet lost less fat-free mass (-2.6±3.7 kg (-4%) vs -3.8±4.7 kg (-6%); P<0.01). Both groups experienced similar increases in high-density lipoprotein cholesterol (8%) and reductions in total cholesterol (-7%), low-density lipoprotein cholesterol (-9%), triglycerides (-24%), glucose (-3%), insulin (-38%), blood pressure (-7/-12%) and C-reactive protein (-29%), (P0.14). In overweight and obese men, both a HP and HC diet reduced body weight and improved cardiometabolic risk factors. Consumption of a HP diet was more effective for improving body composition compared with an HC diet.

Analysis of Carbohydrate-Carbohydrate Interactions Using Sugar-Functionalized Silicon Nanoparticles for Cell Imaging.

PubMed

Lai, Chian-Hui; Hütter, Julia; Hsu, Chien-Wei; Tanaka, Hidenori; Varela-Aramburu, Silvia; De Cola, Luisa; Lepenies, Bernd; Seeberger, Peter H

2016-01-13

Protein-carbohydrate binding depends on multivalent ligand display that is even more important for low affinity carbohydrate-carbohydrate interactions. Detection and analysis of these low affinity multivalent binding events are technically challenging. We describe the synthesis of dual-fluorescent sugar-capped silicon nanoparticles that proved to be an attractive tool for the analysis of low affinity interactions. These ultrasmall NPs with sizes of around 4 nm can be used for NMR quantification of coupled sugars. The silicon nanoparticles are employed to measure the interaction between the cancer-associated glycosphingolipids GM3 and Gg3 and the associated kD value by surface plasmon resonance experiments. Cell binding studies, to investigate the biological relevance of these carbohydrate-carbohydrate interactions, also benefit from these fluorescent sugar-capped nanoparticles.

Association Mapping of Cell Wall Synthesis Regulatory Genes and Cell Wall Quality in Switchgrass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bartley, Laura; Wu, Y.; Zhu, L.

Inefficient conversion of biomass to biofuels is one of the main barriers for biofuel production from such materials. Approximately half of polysaccharides in biomass remain unused by typical biochemical conversion methods. Conversion efficiency is influenced by the composition and structure of cell walls of biomass. Grasses such as wheat, maize, and rice, as well as dedicated perennial bioenergy crops, like switchgrass, make up ~55% of biomass that can be produced in the United States. Grass cell walls have a different composition and patterning compared with dicotyledonous plants, including the well-studied model plant, Arabidopsis. This project identified genetic determinants of cellmore » wall composition in grasses using both naturally occurring genetic variation of switchgrass and gene network reconstruction and functional assays in rice. In addition, the project linked functional data in rice and other species to switchgrass improvement efforts through curation of the most abundant class of regulators in the switchgrass genome. Characterizing natural diversity of switchgrass for variation in cell wall composition and properties, also known as quality, provides an unbiased avenue for identifying biologically viable diversity in switchgrass cell walls. To characterizing natural diversity, this project generated cell wall composition and enzymatic deconstruction data for ~450 genotypes of the Switchgrass Southern Association Collection (SSAC), a diverse collection composed of 36 switchgrass accessions from the southern U.S. distribution of switchgrass. Comparing these data with other measures of cell wall quality for the same samples demonstrated the complementary nature of the diverse characterization platforms now being used for biomass characterization. Association of the composition data with ~3.2K single nucleotide variant markers identified six significant single nucleotide variant markers co-associated with digestibility and another compositional trait

Colorimetric measurement of carbohydrates in biological wastewater treatment systems: A critical evaluation.

PubMed

Le, Chencheng; Stuckey, David C

2016-05-01

Four laboratory preparations and three commercially available assay kits were tested on the same carbohydrate samples with the addition of 14 different interfering solutes typically found in wastewater treatment plants. This work shows that a wide variety of solutes can interfere with these assays. In addition, a comparative study on the use of these assays with different carbohydrate samples was also carried out, and the metachromatic response was clearly influenced by variation in sample composition. The carbohydrate content in the supernatant of a submerged anaerobic membrane bioreactor (SAMBR) was also measured using these assays, and the amount in the different supernatant samples, with and without a standard addition of glucose to the samples, showed substantial differences. We concluded that the carbohydrates present in wastewater measured using these colorimetric methods could be seriously under- or over-estimated. A new analytical method needs to be developed in order to better understand the biological transformations occurring in anaerobic digestion that leads to the production of soluble microbial products (SMPs) and extracellular polymeric substance (EPS). Copyright © 2016 Elsevier Ltd. All rights reserved.

Learning about Carbohydrates

MedlinePlus

... added sugar and doesn't contain important nutrients. Complex carbohydrates: These are also called starches. Starches include grain ... pasta, and rice. As with simple sugars, some complex carbohydrate foods are better choices than others. Refined (say: ...

Preparation and characterization of functionalized single walled carbon nanotubes (fSWCNT)/ Hydroxyapatite (HAp)-Nylon hybridized composite biomaterial to study the mechanical properties

NASA Astrophysics Data System (ADS)

Khanal, Suraj; Leventouri, Theodora; Mahfuz, Hassan; Rondinone, Adam

2014-03-01

Synthetic hydroxyapatite (HAp) bears poor mechanical properties that limit its applicability in orthopedics. We study the possibility of overcoming such limitations by incorporating functionalized single walled carbon nanotubes (fSWCNT) in a biocompatible/bioactive nano-composite. We present results from synthesis and characterization of samples prepared under different processing parameters. Ultra sonication method was to disperse functionalized single walled carbon nanotubes (fSWCNT) in HAp followed by a simple hot assorting method to incorporate with polymerized ɛ-caprolactam. The fracture toughness of the composite materials was tested in compliance with the ASTM D-5045 standard. We have found that while the fracture toughness strongly depends on the processing parameters, a value comparable to the one for cortical bone is achieved. Mechanical properties, electron microscopy and crystal structure properties of the composite materials will be discussed.

Carbohydrates and Diabetes

MedlinePlus

... Staying Safe Videos for Educators Search English Español Carbohydrates and Diabetes KidsHealth / For Teens / Carbohydrates and Diabetes ... Los carbohidratos y la diabetes Carbs and Blood Sugar Keeping your blood sugar levels on track means ...

Nickel-catalyzed proton-deuterium exchange (HDX) for linkage analysis of complex carbohydrates

USDA-ARS?s Scientific Manuscript database

The structural assignment of complex carbohydrates typically requires the analysis of at least three parameters: 1. composition; 2. linkage; and 3. substituents. These are often assigned on a small scale by gas chromatography/mass spectrometry (GC/MS). Linkage positions are determined by permethylat...

Impact of Dietary Carbohydrate and Protein Levels on Carbohydrate Metabolism

ERIC Educational Resources Information Center

Lasker, Denise Ann

2009-01-01

The goal of this dissertation was to investigate the impact of changing dietary carbohydrate (CARB) intakes within recommended dietary guidelines on metabolic outcomes specifically associated with glycemic regulations and carbohydrate metabolism. This research utilized both human and animal studies to examine changes in metabolism across a wide…

Experimental, numerical, and analytical studies on the seismic response of steel-plate concrete (SC) composite shear walls

NASA Astrophysics Data System (ADS)

Epackachi, Siamak

The seismic performance of rectangular steel-plate concrete (SC) composite shear walls is assessed for application to buildings and mission-critical infrastructure. The SC walls considered in this study were composed of two steel faceplates and infill concrete. The steel faceplates were connected together and to the infill concrete using tie rods and headed studs, respectively. The research focused on the in-plane behavior of flexure- and flexure-shear-critical SC walls. An experimental program was executed in the NEES laboratory at the University at Buffalo and was followed by numerical and analytical studies. In the experimental program, four large-size specimens were tested under displacement-controlled cyclic loading. The design variables considered in the testing program included wall thickness, reinforcement ratio, and slenderness ratio. The aspect ratio (height-to-length) of the four walls was 1.0. Each SC wall was installed on top of a re-usable foundation block. A bolted baseplate to RC foundation connection was used for all four walls. The walls were identified to be flexure- and flexure-shear critical. The progression of damage in the four walls was identical, namely, cracking and crushing of the infill concrete at the toes of the walls, outward buckling and yielding of the steel faceplates near the base of the wall, and tearing of the faceplates at their junctions with the baseplate. A robust finite element model was developed in LS-DYNA for nonlinear cyclic analysis of the flexure- and flexure-shear-critical SC walls. The DYNA model was validated using the results of the cyclic tests of the four SC walls. The validated and benchmarked models were then used to conduct a parametric study, which investigated the effects of wall aspect ratio, reinforcement ratio, wall thickness, and uniaxial concrete compressive strength on the in-plane response of SC walls. Simplified analytical models, suitable for preliminary analysis and design of SC walls, were

Cell wall polysaccharides from fern leaves: evidence for a mannan-rich Type III cell wall in Adiantum raddianum.

PubMed

Silva, Giovanna B; Ionashiro, Mari; Carrara, Thalita B; Crivellari, Augusto C; Tiné, Marco A S; Prado, Jefferson; Carpita, Nicholas C; Buckeridge, Marcos S

2011-12-01

Primary cell walls from plants are composites of cellulose tethered by cross-linking glycans and embedded in a matrix of pectins. Cell wall composition varies between plant species, reflecting in some instances the evolutionary distance between them. In this work the monosaccharide compositions of isolated primary cell walls of nine fern species and one lycophyte were characterized and compared with those from Equisetum and an angiosperm dicot. The relatively high abundance of mannose in these plants suggests that mannans may constitute the major cross-linking glycan in the primary walls of pteridophytes and lycophytes. Pectin-related polysaccharides contained mostly rhamnose and uronic acids, indicating the presence of rhamnogalacturonan I highly substituted with galactose and arabinose. Structural and fine-structural analyses of the hemicellulose fraction of leaves of Adiantum raddianum confirmed this hypothesis. Linkage analysis showed that the mannan contains mostly 4-Man with very little 4,6-Man, indicating a low percentage of branching with galactose. Treatment of the mannan-rich fractions with endo-β-mannanase produced characteristic mannan oligosaccharides. Minor amounts of xyloglucan and xylans were also detected. These data and those of others suggest that all vascular plants contain xyloglucans, arabinoxylans, and (gluco)mannans, but in different proportions that define cell wall types. Whereas xyloglucan and pectin-rich walls define Type I walls of dicots and many monocots, arabinoxylans and lower proportion of pectin define the Type II walls of commelinoid monocots. The mannan-rich primary walls with low pectins of many ferns and a lycopod indicate a fundamentally different wall type among land plants, the Type III wall. Copyright © 2011 Elsevier Ltd. All rights reserved.

Weight and Metabolic Outcomes After 2 Years on a Low-Carbohydrate Versus Low-Fat Diet

PubMed Central

Foster, Gary D.; Wyatt, Holly R.; Hill, James O.; Makris, Angela P.; Rosenbaum, Diane L.; Brill, Carrie; Stein, Richard I.; Mohammed, B. Selma; Miller, Bernard; Rader, Daniel J.; Zemel, Babette; Wadden, Thomas A.; Tenhave, Thomas; Newcomb, Craig W.; Klein, Samuel

2010-01-01

Background Previous studies comparing low-carbohydrate and low-fat diets have not included a comprehensive behavioral treatment, resulting in suboptimal weight loss. Objective To evaluate the effects of 2-year treatment with a low-carbohydrate or low-fat diet, each of which was combined with a comprehensive lifestyle modification program. Design Randomized parallel-group trial. (ClinicalTrials.gov registration number: NCT00143936) Setting 3 academic medical centers. Patients 307 participants with a mean age of 45.5 years (SD, 9.7 years) and mean body mass index of 36.1 kg/m2 (SD, 3.5 kg/m2). Intervention A low-carbohydrate diet, which consisted of limited carbohydrate intake (20 g/d for 3 months) in the form of low–glycemic index vegetables with unrestricted consumption of fat and protein. After 3 months, participants in the low-carbohydrate diet group increased their carbohydrate intake (5 g/d per wk) until a stable and desired weight was achieved. A low-fat diet consisted of limited energy intake (1200 to 1800 kcal/d; ≤30% calories from fat). Both diets were combined with comprehensive behavioral treatment. Measurements Weight at 2 years was the primary outcome. Secondary measures included weight at 3, 6, and 12 months and serum lipid concentrations, blood pressure, urinary ketones, symptoms, bone mineral density, and body composition throughout the study. Results Weight loss was approximately 11 kg (11%) at 1 year and 7 kg (7%) at 2 years. There were no differences in weight, body composition, or bone mineral density between the groups at any time point. During the first 6 months, the low-carbohydrate diet group had greater reductions in diastolic blood pressure, triglyceride levels, and very-low-density lipoprotein cholesterol levels, lesser reductions in low-density lipoprotein cholesterol levels, and more adverse symptoms than did the low-fat diet group. The low-carbohydrate diet group had greater increases in high-density lipoprotein cholesterol levels

Overexpression of the carbohydrate binding module from Solanum lycopersicum expansin 1 (Sl-EXP1) modifies tomato fruit firmness and Botrytis cinerea susceptibility.

PubMed

Perini, M A; Sin, I N; Villarreal, N M; Marina, M; Powell, A L T; Martínez, G A; Civello, P M

2017-04-01

Firmness, one of the major determinants of postharvest quality and shelf life of fruits is determined by the mechanical resistance imposed by the plant cell wall. Expansins (EXP) are involved in the non-hydrolytic metabolic disassembly of plant cell walls, particularly in processes where relaxation of the wall is necessary, such as fruit development and ripening. As many carbohydrate-associated proteins, expansins have a putative catalytic domain and a carbohydrate-binding module (CBM). Several strategies have been pursued to control the loss of fruit firmness during storage. Most of the approaches have been to suppress the expression of key enzymes involved in the cell wall metabolism, but this is the first time that a CBM was overexpressed in a fruit aimed to control cell wall degradation and fruit softening. We report the constitutive overexpression of the CBM of Solanum lycopersicum expansin 1 (CBM-SlExp1) in the cell wall of tomato plants, and its effects on plant and fruit phenotype. Overexpression of CBM-SlExp1 increased the mechanical resistance of leaves, whereas it did not modify plant growth and general phenotype. However, transgenic plants showed delayed softening and firmer fruits. In addition, fruits were less susceptible to Botrytis cinerea infection, and the "in vitro" growth of the fungus on media containing AIR from the pericarp of transgenic fruits was lower than controls. The possibility of overexpressing a CBM of a fruit-specific expansin to control cell wall degradation and fruit softening is discussed. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Sertraline inhibits increases in body fat and carbohydrate dysregulation in adult female cynomolgus monkeys

PubMed Central

Silverstein-Metzler, Marnie G.; Shively, Carol A.; Clarkson, Thomas B.; Appt, Susan E.; Carr, J.Jeffrey; Kritchevsky, Stephen B.; Jones, Sara R.; Register, Thomas C.

2017-01-01

Selective serotonin reuptake inhibitor (SSRI) antidepressants are widely prescribed for depression and other disorders. SSRIs have become one of the most commonly used drugs in the United States, particularly by women. Acute effects on body composition and carbohydrate metabolism have been reported, but little is known regarding the effects of chronic SSRI use. We evaluated the effects of chronic administration of a commonly prescribed SSRI, sertraline HCl, on body weight and composition, fat distribution, carbohydrate metabolism, as well as activity, in adult female depressed and nondepressed cynomolgus monkeys (Macaca fascicularis; n = 42) using a placebo-controlled, longitudinal, randomized study design. Phenotypes were evaluated prior to and after 18 months of oral sertraline (20 mg/kg) or placebo. Over the 18 month treatment period, the placebo group experienced increases in body weight, body fat (visceral and subcutaneous) fasting insulin concentrations, and homeostasis model assessment of insulin resistance scores (HOMA-IR). Sertraline treatment prevented increases in body weight, fat, insulin, and HOMA-IR (all p < 0.05), without significantly altering activity levels. Sertraline treatment altered adiponectin in an unusual way — reducing circulating adiponectin in depressed monkeys without affecting fat mass or body weight. Deleterious effects on adiponectin, a potentially insulin-sensitizing and atheroprotective protein, may result in adverse effects on cardiovascular health despite otherwise beneficial effects on body composition and carbohydrate metabolism. PMID:26939086

Carbohydrate composition and in vitro digestibility of dry matter and nonstarch polysaccharides in corn, sorghum, and wheat and coproducts from these grains.

PubMed

Jaworski, N W; Lærke, H N; Bach Knudsen, K E; Stein, H H

2015-03-01

The objectives of this work were to determine carbohydrate composition and in vitro digestibility of DM and nonstarch polysaccharides (NSP) in corn, wheat, and sorghum and coproducts from these grains. In the initial part of this work, the carbohydrate composition of 12 feed ingredients was determined. The 12 ingredients included 3 grains (corn, sorghum, and wheat), 3 coproducts from the dry grind industry (corn distillers dried grains with solubles [DDGS] and 2 sources of sorghum DDGS), 4 coproducts from the wet milling industry (corn gluten meal, corn gluten feed, corn germ meal, and corn bran), and 2 coproducts from the flour milling industry (wheat middlings and wheat bran). Results indicated that grains contained more starch and less NSP compared with grain coproducts. The concentration of soluble NSP was low in all ingredients. Cellulose, arabinoxylans, and other hemicelluloses made up approximately 22, 49, and 29% (DM basis), respectively, of the NSP in corn and corn coproducts and approximately 25, 43, and 32% (DM basis), respectively, of the NSP in sorghum and sorghum DDGS. Cellulose, arabinoxylans, and other hemicelluloses made up approximately 16, 64, and 20% (DM basis), respectively, of the NSP in wheat and wheat coproducts. The concentration of lignin in grains was between 0.8 and 1.8% (DM basis), whereas coproducts contained between 2.2 and 11.5% lignin (DM basis). The in vitro ileal digestibility of NSP was close to zero or negative for all feed ingredients, indicating that pepsin and pancreas enzymes have no effect on in vitro degradation of NSP. A strong negative correlation ( = 0.97) between in vitro ileal digestibility of DM and the concentration of NSP in feed ingredients was observed. In vitro total tract digestibility of NSP ranged from 6.5% in corn bran to 57.3% in corn gluten meal. In conclusion, grains and grain coproducts contain mostly insoluble NSP and arabinoxylans make up the majority of the total NSP fraction. The in vitro

Polyunsaturated fats, carbohydrates and carotid disease: The Atherosclerosis Risk in Communities (ARIC) Carotid MRI study

PubMed Central

Dearborn, Jennifer L.; Qiao, Ye; Guallar, Eliseo; Steffen, Lyn M.; Gottesman, Rebecca F.; Zhang, Yiyi; Wasserman, Bruce A.

2016-01-01

Background and aims Carbohydrates and fat intake have both been linked to development of atherosclerosis. We examined associations between glycemic index GI and fat intake with carotid atherosclerosis. Methods The Atherosclerosis Risk in Communities (ARIC) cohort enrolled participants during the period 1987–1989 and the Carotid MRI sub-study occurred between 2004 and 2006 (1,672 participants attending both visits). Measures of carbohydrate quality (usual GI), fat intake (total, polyunsaturated and saturated) and overall dietary quality index (DASH Diet Score) were derived from a 66-item food frequency questionnaire administered at baseline. Trained readers measured lipid core presence and maximum wall thickness. Using multivariate logistic regression, we determined the odds of lipid core presence by quintile (Q) of energy-adjusted dietary components. Restricted cubic spline models were used to examine non-linear associations between dietary components and maximum wall thickness. Results Mean daily polyunsaturated fat intake was 5 g (SD 1.4). GI and polyunsaturated fat intake had a nonlinear relationship with maximum wall thickness. Low (1–4 g) and high (6–12 g) polyunsaturated fat intake were associated with a statistically significant decreased odds of lipid core presence compared to intake in a majority of participants (OR Q5 vs. Q2–4: 0.64, 95% CI 0.42 to 0.98; OR Q1 vs. Q2–4: 0.64, 95% CI 0.42, 0.96), however, the association with lipid core was attenuated by adjustment for maximum wall thickness, hypertension, hyperlipidemia, and diabetes. Conclusions GI and polyunsaturated fat intake were not associated with high-risk plaque features, such as lipid core presence, independent of traditional vascular risk factors. PMID:27234460

Polyunsaturated fats, carbohydrates and carotid disease: The Atherosclerosis Risk in Communities (ARIC) Carotid MRI study.

PubMed

Dearborn, Jennifer L; Qiao, Ye; Guallar, Eliseo; Steffen, Lyn M; Gottesman, Rebecca F; Zhang, Yiyi; Wasserman, Bruce A

2016-08-01

Carbohydrates and fat intake have both been linked to development of atherosclerosis. We examined associations between glycemic index (GI) and fat intake with carotid atherosclerosis. The Atherosclerosis Risk in Communities (ARIC) cohort enrolled participants during the period 1987-1989 and the Carotid MRI sub-study occurred between 2004 and 2006 (1672 participants attending both visits). Measures of carbohydrate quality (usual GI), fat intake (total, polyunsaturated and saturated) and overall dietary quality index (DASH Diet Score) were derived from a 66-item food frequency questionnaire administered at baseline. Trained readers measured lipid core presence and maximum wall thickness. Using multivariate logistic regression, we determined the odds of lipid core presence by quintile (Q) of energy-adjusted dietary components. Restricted cubic spline models were used to examine non-linear associations between dietary components and maximum wall thickness. Mean daily polyunsaturated fat intake was 5 g (SD 1.4). GI and polyunsaturated fat intake had a nonlinear relationship with maximum wall thickness. Low (1-4 g) and high (6-12 g) polyunsaturated fat intake were associated with a statistically significant decreased odds of lipid core presence compared to intake in a majority of participants (OR Q5 vs. Q2-4: 0.64, 95% CI 0.42 to 0.98; OR Q1 vs. Q2-4: 0.64, 95% CI 0.42, 0.96), however, the association with lipid core was attenuated by adjustment for maximum wall thickness, hypertension, hyperlipidemia, and diabetes. GI and polyunsaturated fat intake were not associated with high-risk plaque features, such as lipid core presence, independent of traditional vascular risk factors. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Wall contraction in Bloch wall films

NASA Technical Reports Server (NTRS)

Bartran, D. S.; Bourne, H. C., Jr.

1972-01-01

The phenomenon of wall contraction characterized by a peak in the velocity field relationship and a region of negative differential mobility is observed. Uniaxial magnetic thin films of various compositions and magnetic properties are studied in careful interrupted pulse experiments. The observed results agree quite well with the theory for bulk samples.

Silver colloidal nanoparticles: effect on matrix composition and structure of Candida albicans and Candida glabrata biofilms.

PubMed

Monteiro, D R; Silva, S; Negri, M; Gorup, L F; de Camargo, E R; Oliveira, R; Barbosa, D B; Henriques, M

2013-04-01

The aim of this study was to assess the effect of different silver nanoparticles (SN) concentrations on the matrix composition and structure of Candida albicans and Candida glabrata biofilms. Candida biofilms were developed in 6-well microtiter plates during 48 h. After, these biofilms were exposed to 13.5 or 54 μg SN ml(-1) for 24 h. Then, extracellular matrices were extracted from biofilms and analysed chemically in terms of proteins, carbohydrates and DNA. To investigate the biofilm structure, scanning electron microscopy (SEM) and epifluorescence microscopy were used. SN interfered with the matrix composition of Candida biofilms tested in terms of protein, carbohydrate and DNA, except for the protein content of C. albicans biofilm. By SEM, Candida biofilms treated with SN revealed structural differences, when compared with the control groups. Further, SN showed a trend of agglomeration within the biofilms. Epifluorescence microscopy images suggest that SN induced damage on cell walls of the Candida isolates tested. In general, irrespective of concentration, SN affected the matrix composition and structure of Candida biofilms and these findings may be related to the mechanisms of biocide action of SN. This study reveals new insights about the behaviour of SN when in contact with Candida biofilms. SN may contribute to the development of therapies to prevent or control Candida infections. © 2012 The Society for Applied Microbiology.

Optimum Material Composition for Minimizing the Stress Intensity Factor of Edge Crack in Thick-Walled FGM Circular Pipes Under Thermomechanical Loading

NASA Astrophysics Data System (ADS)

Sekine, Hideki; Yoshida, Kimiaki

This paper deals with the optimization problem of material composition for minimizing the stress intensity factor of radial edge crack in thick-walled functionally graded material (FGM) circular pipes under steady-state thermomechanical loading. Homogenizing the FGM circular pipes by simulating the inhomogeneity of thermal conductivity by a distribution of equivalent eigentemperature gradient and the inhomogeneity of Young's modulus and Poisson's ratio by a distribution of equivalent eigenstrain, we present an approximation method to obtain the stress intensity factor of radial edge crack in the FGM circular pipes. The optimum material composition for minimizing the stress intensity factor of radial edge crack is determined using a nonlinear mathematical programming method. Numerical results obtained for a thick-walled TiC/Al2O3 FGM circular pipe reveal that it is possible to decrease remarkably the stress intensity factor of radial edge crack by setting the optimum material composition profile.

Daily Overfeeding from Protein and/or Carbohydrate Supplementation for Eight Weeks in Conjunction with Resistance Training Does not Improve Body Composition and Muscle Strength or Increase Markers Indicative of Muscle Protein Synthesis and Myogenesis in Resistance-Trained Males

PubMed Central

Spillane, Mike; Willoughby, Darryn S.

2016-01-01

This study determined the effects of heavy resistance training and daily overfeeding with carbohydrate and/or protein on blood and skeletal muscle markers of protein synthesis (MPS), myogenesis, body composition, and muscle performance. Twenty one resistance-trained males were randomly assigned to either a protein + carbohydrate [HPC (n = 11)] or a carbohydrate [HC (n = 10)] supplement group in a double-blind fashion. Body composition and muscle performance were assessed, and venous blood samples and muscle biopsies were obtained before and after eight weeks of resistance training and supplementation. Data were analyzed by two-way ANOVA (p ≤ 0.05). Total body mass, body water, and fat mass were significantly increased in both groups in response to resistance training, but not supplementation (p < 0.05); however, lean mass was not significantly increased in either group (p = 0.068). Upper- (p = 0.024) and lower-body (p = 0.001) muscle strength and myosin heavy chain (MHC) 1 (p = 0.039) and MHC 2A (p = 0.027) were also significantly increased with resistance training. Serum IGF-1, GH, and HGF were not significantly affected (p > 0.05). Muscle total DNA, total protein, and c-Met were not significantly affected (p > 0.05). In conjunction with resistance training, the peri-exercise and daily overfeeding of protein and/or carbohydrate did not preferentially improve body composition, muscle performance, and markers indicative of MPS and myogenic activation. Key points In response to 56 days of heavy resistance training and HC or HPC supplementation, similar increases in muscle mass and strength in both groups occurred; however, the increases were not different between supplement groups. The supplementation of HPC had no preferential effect on augmenting serum IGF-1 GH, or HGF. The supplementation of HPC had no preferential effect on augmenting increases in total muscle protein content or the myogenic markers, total DNA and muscle cMet content. In response to 56 days of

Electronic Detection of Lectins Using Carbohydrate Functionalized Nanostructures: Graphene versus Carbon Nanotubes

PubMed Central

Chen, Yanan; Vedala, Harindra; Kotchey, Gregg P.; Audfray, Aymeric; Cecioni, Samy; Imberty, Anne; Vidal, Sébastien; Star, Alexander

2012-01-01

Here we investigated the interactions between lectins and carbohydrates using field-effect transistor (FET) devices comprised of chemically converted graphene (CCG) and single-walled carbon nanotubes (SWNTs). Pyrene- and porphyrin-based glycoconjugates were functionalized noncovalently on the surface of CCG-FET and SWNT-FET devices, which were then treated with 2 µM of nonspecific and specific lectins. In particular, three different lectins (PA-IL, PA-IIL and ConA) and three carbohydrate epitopes (galactose, fucose and mannose) were tested. The responses of 36 different devices were compared and rationalized using computer-aided models of carbon nanostructure/glycoconjugate interactions. Glycoconjugates surface coverage in addition to one-dimensional structures of SWNTs resulted in optimal lectin detection. Additionally, lectin titration data of SWNT- and CCG-based biosensors were used to calculate lectin dissociation constants (Kd) and compare them to the values obtained from the isothermal titration microcalorimetry (ITC) technique. PMID:22136380

Application of Polypyrrole Multi-Walled Carbon Nanotube Composite Layer for Detection of Mercury, Lead and Iron Ions Using Surface Plasmon Resonance Technique

PubMed Central

Sadrolhosseini, Amir Reza; Noor, A. S. M.; Bahrami, Afarin; Lim, H. N.; Talib, Zainal Abidin; Mahdi, Mohd. Adzir

2014-01-01

Polypyrrole multi-walled carbon nanotube composite layers were used to modify the gold layer to measure heavy metal ions using the surface plasmon resonance technique. The new sensor was fabricated to detect trace amounts of mercury (Hg), lead (Pb), and iron (Fe) ions. In the present research, the sensitivity of a polypyrrole multi-walled carbon nanotube composite layer and a polypyrrole layer were compared. The application of polypyrrole multi-walled carbon nanotubes enhanced the sensitivity and accuracy of the sensor for detecting ions in an aqueous solution due to the binding of mercury, lead, and iron ions to the sensing layer. The Hg ion bonded to the sensing layer more strongly than did the Pb and Fe ions. The limitation of the sensor was calculated to be about 0.1 ppm, which produced an angle shift in the region of 0.3° to 0.6°. PMID:24733263

The carbohydrate sequence markup language (CabosML): an XML description of carbohydrate structures.

PubMed

Kikuchi, Norihiro; Kameyama, Akihiko; Nakaya, Shuuichi; Ito, Hiromi; Sato, Takashi; Shikanai, Toshihide; Takahashi, Yoriko; Narimatsu, Hisashi

2005-04-15

Bioinformatics resources for glycomics are very poor as compared with those for genomics and proteomics. The complexity of carbohydrate sequences makes it difficult to define a common language to represent them, and the development of bioinformatics tools for glycomics has not progressed. In this study, we developed a carbohydrate sequence markup language (CabosML), an XML description of carbohydrate structures. The language definition (XML Schema) and an experimental database of carbohydrate structures using an XML database management system are available at http://www.phoenix.hydra.mki.co.jp/CabosDemo.html kikuchi@hydra.mki.co.jp.

Synthesis of carbohydrate-based surfactants

DOEpatents

Pemberton, Jeanne E.; Polt, Robin L.; Maier, Raina M.

2016-11-22

The present invention provides carbohydrate-based surfactants and methods for producing the same. Methods for producing carbohydrate-based surfactants include using a glycosylation promoter to link a carbohydrate or its derivative to a hydrophobic compound.

Decoration of multi-walled carbon nanotubes by polymer wrapping and its application in MWCNT/polyethylene composites

PubMed Central

2012-01-01

We dispersed the non-covalent functionalization of multi-walled carbon nanotubes (CNTs) with a polymer dispersant and obtained a powder of polymer-wrapped CNTs. The UV–vis absorption spectrum was used to investigate the optimal weight ratio of the CNTs and polymer dispersant. The powder of polymer-wrapped CNTs had improved the drawbacks of CNTs of being lightweight and difficult to process, and it can re-disperse in a solvent. Then, we blended the polymer-wrapped CNTs and polyethylene (PE) by melt-mixing and produced a conductive masterbatch and CNT/PE composites. The polymer-wrapped CNTs showed lower surface resistivity in composites than the raw CNTs. The scanning electron microscopy images also showed that the polymer-wrapped CNTs can disperse well in composites than the raw CNTs. PMID:22559082

A comparative study of monosaccharide composition analysis as a carbohydrate test for biopharmaceuticals.

PubMed

Harazono, Akira; Kobayashi, Tetsu; Kawasaki, Nana; Itoh, Satsuki; Tada, Minoru; Hashii, Noritaka; Ishii, Akiko; Arato, Teruyo; Yanagihara, Shigehiro; Yagi, Yuki; Koga, Akiko; Tsuda, Yuriko; Kimura, Mikiko; Sakita, Masashi; Kitamura, Satoshi; Yamaguchi, Hideto; Mimura, Hisashi; Murata, Yoshimi; Hamazume, Yasuki; Sato, Takayuki; Natsuka, Shunji; Kakehi, Kazuaki; Kinoshita, Mitsuhiro; Watanabe, Sakie; Yamaguchi, Teruhide

2011-05-01

The various monosaccharide composition analysis methods were evaluated as monosaccharide test for glycoprotein-based pharmaceuticals. Neutral and amino sugars were released by hydrolysis with 4-7N trifluoroacetic acid. The monosaccharides were N-acetylated if necessary, and analyzed by high-performance liquid chromatography (HPLC) with fluorometric or UV detection after derivatization with 2-aminopyridine, ethyl 4-aminobenzoate, 2-aminobenzoic acid or 1-phenyl-3-methyl-5-pyrazolone, or high pH anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD). Sialic acids were released by mild acid hydrolysis or sialidase digestion, and analyzed by HPLC with fluorometric detection after derivatization with 1,2-diamino-4,5-methylenedioxybenzene, or HPAEC-PAD. These methods were verified for resolution, linearity, repeatability, and accuracy using a monosaccharide standard solution, a mixture of epoetin alfa and beta, and alteplase as models. It was confirmed that those methods were useful for ensuring the consistency of glycosylation. It is considered essential that the analytical conditions including desalting, selection of internal standards, release of monosaccharides, and gradient time course should be determined carefully to eliminate interference of sample matrix. Various HPLC-based monosaccharide analysis methods were evaluated as a carbohydrate test for glycoprotein pharmaceuticals by an inter-laboratory study. Copyright © 2011 The International Association for Biologicals. Published by Elsevier Ltd. All rights reserved.

Accumulation of N-Acetylglucosamine Oligomers in the Plant Cell Wall Affects Plant Architecture in a Dose-Dependent and Conditional Manner1[W][OPEN

PubMed Central

Vanholme, Bartel; Vanholme, Ruben; Turumtay, Halbay; Goeminne, Geert; Cesarino, Igor; Goubet, Florence; Morreel, Kris; Rencoret, Jorge; Bulone, Vincent; Hooijmaijers, Cortwa; De Rycke, Riet; Gheysen, Godelieve; Ralph, John; De Block, Marc; Meulewaeter, Frank; Boerjan, Wout

2014-01-01

To study the effect of short N-acetylglucosamine (GlcNAc) oligosaccharides on the physiology of plants, N-ACETYLGLUCOSAMINYLTRANSFERASE (NodC) of Azorhizobium caulinodans was expressed in Arabidopsis (Arabidopsis thaliana). The corresponding enzyme catalyzes the polymerization of GlcNAc and, accordingly, β-1,4-GlcNAc oligomers accumulated in the plant. A phenotype characterized by difficulties in developing an inflorescence stem was visible when plants were grown for several weeks under short-day conditions before transfer to long-day conditions. In addition, a positive correlation between the oligomer concentration and the penetrance of the phenotype was demonstrated. Although NodC overexpression lines produced less cell wall compared with wild-type plants under nonpermissive conditions, no indications were found for changes in the amount of the major cell wall polymers. The effect on the cell wall was reflected at the transcriptome level. In addition to genes encoding cell wall-modifying enzymes, a whole set of genes encoding membrane-coupled receptor-like kinases were differentially expressed upon GlcNAc accumulation, many of which encoded proteins with an extracellular Domain of Unknown Function26. Although stress-related genes were also differentially expressed, the observed response differed from that of a classical chitin response. This is in line with the fact that the produced chitin oligomers were too small to activate the chitin receptor-mediated signal cascade. Based on our observations, we propose a model in which the oligosaccharides modify the architecture of the cell wall by acting as competitors in carbohydrate-carbohydrate or carbohydrate-protein interactions, thereby affecting noncovalent interactions in the cell wall or at the interface between the cell wall and the plasma membrane. PMID:24664205

Physics-Based Simulation and Experiment on Blast Protection of Infill Walls and Sandwich Composites Using New Generation of Nano Particle Reinforced Materials

NASA Astrophysics Data System (ADS)

Irshidat, Mohammad

A critical issue for the development of nanotechnology is our ability to understand, model, and simulate the behavior of small structures and to make the connection between nano structure properties and their macroscopic functions. Material modeling and simulation helps to understand the process, to set the objectives that could guide laboratory efforts, and to control material structures, properties, and processes at physical implementation. These capabilities are vital to engineering design at the component and systems level. In this research, experimental-computational-analytical program was employed to investigate the performance of the new generation of polymeric nano-composite materials, like nano-particle reinforced elastomeric materials (NPREM), for the protection of masonry structures against blast loads. New design tools for using these kinds of materials to protect Infill Walls (e.g. masonry walls) against blast loading were established. These tools were also extended to cover other type of panels like sandwich composites. This investigation revealed that polymeric nano composite materials are strain rate sensitive and have large amount of voids distributed randomly inside the materials. Results from blast experiments showed increase in ultimate flexural resistance achieved by both unreinforced and nano reinforced polyurea retrofit systems applied to infill masonry walls. It was also observed that a thin elastomeric coating on the interior face of the walls could be effective at minimizing the fragmentation resulting from blast. More conclusions are provided with recommended future research.

Carbohydrates and Diabetes (For Parents)

MedlinePlus

... Staying Safe Videos for Educators Search English Español Carbohydrates and Diabetes KidsHealth / For Parents / Carbohydrates and Diabetes ... many kids with diabetes take to stay healthy. Carbohydrates and Blood Sugar The two main forms of ...

Bioavailability of Carbohydrate Content in Natural and Transgenic Switchgrasses for the Extreme Thermophile Caldicellulosiruptor bescii

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zurawski, Jeffrey V.; Khatibi, Piyum A.; Akinosho, Hannah O.

ABSTRACT Improving access to the carbohydrate content of lignocellulose is key to reducing recalcitrance for microbial deconstruction and conversion to fuels and chemicals. Caldicellulosiruptor bescii completely solubilizes naked microcrystalline cellulose, yet this transformation is impeded within the context of the plant cell wall by a network of lignin and hemicellulose. Here, the bioavailability of carbohydrates toC. bescii at 70°C was examined for reduced lignin transgenic switchgrass lines COMT3(+) and MYB Trans, their corresponding parental lines (cultivar Alamo) COMT3(–) and MYB wild type (WT), and the natural variant cultivar Cave-in-Rock (CR). Transgenic modification improved carbohydrate solubilization by C. bescii to 15%more » (2.3-fold) for MYB and to 36% (1.5-fold) for COMT, comparable to the levels achieved for the natural variant, CR (36%). Carbohydrate solubilization was nearly doubled after two consecutive microbial fermentations compared to one microbial step, but it never exceeded 50% overall. Hydrothermal treatment (180°C) prior to microbial steps improved solubilization 3.7-fold for the most recalcitrant line (MYB WT) and increased carbohydrate recovery to nearly 50% for the least recalcitrant lines [COMT3(+) and CR]. Alternating microbial and hydrothermal steps (T→M→T→M) further increased bioavailability, achieving carbohydrate solubilization ranging from 50% for MYB WT to above 70% for COMT3(+) and CR. Incomplete carbohydrate solubilization suggests that cellulose in the highly lignified residue was inaccessible; indeed, residue from the T→M→T→M treatment was primarily glucan and inert materials (lignin and ash). While C. bescii could significantly solubilize the transgenic switchgrass lines and natural variant tested here, additional or alternative strategies (physical, chemical, enzymatic, and/or genetic) are needed to eliminate recalcitrance.« less

Bioavailability of Carbohydrate Content in Natural and Transgenic Switchgrasses for the Extreme Thermophile Caldicellulosiruptor bescii

DOE PAGES

Zurawski, Jeffrey V.; Khatibi, Piyum A.; Akinosho, Hannah O.; ...

2017-06-16

ABSTRACT Improving access to the carbohydrate content of lignocellulose is key to reducing recalcitrance for microbial deconstruction and conversion to fuels and chemicals. Caldicellulosiruptor bescii completely solubilizes naked microcrystalline cellulose, yet this transformation is impeded within the context of the plant cell wall by a network of lignin and hemicellulose. Here, the bioavailability of carbohydrates toC. bescii at 70°C was examined for reduced lignin transgenic switchgrass lines COMT3(+) and MYB Trans, their corresponding parental lines (cultivar Alamo) COMT3(–) and MYB wild type (WT), and the natural variant cultivar Cave-in-Rock (CR). Transgenic modification improved carbohydrate solubilization by C. bescii to 15%more » (2.3-fold) for MYB and to 36% (1.5-fold) for COMT, comparable to the levels achieved for the natural variant, CR (36%). Carbohydrate solubilization was nearly doubled after two consecutive microbial fermentations compared to one microbial step, but it never exceeded 50% overall. Hydrothermal treatment (180°C) prior to microbial steps improved solubilization 3.7-fold for the most recalcitrant line (MYB WT) and increased carbohydrate recovery to nearly 50% for the least recalcitrant lines [COMT3(+) and CR]. Alternating microbial and hydrothermal steps (T→M→T→M) further increased bioavailability, achieving carbohydrate solubilization ranging from 50% for MYB WT to above 70% for COMT3(+) and CR. Incomplete carbohydrate solubilization suggests that cellulose in the highly lignified residue was inaccessible; indeed, residue from the T→M→T→M treatment was primarily glucan and inert materials (lignin and ash). While C. bescii could significantly solubilize the transgenic switchgrass lines and natural variant tested here, additional or alternative strategies (physical, chemical, enzymatic, and/or genetic) are needed to eliminate recalcitrance.« less

Dynamics of biomass partitioning, stem gene expression, cell wall biosynthesis, and sucrose accumulation during development of Sorghum bicolor.

PubMed

McKinley, Brian; Rooney, William; Wilkerson, Curtis; Mullet, John

2016-11-01

Biomass accumulated preferentially in leaves of the sweet sorghum Della until floral initiation, then stems until anthesis, followed by panicles until grain maturity, and apical tillers. Sorghum stem RNA-seq transcriptome profiles and composition data were collected for approximately 100 days of development beginning at floral initiation. The analysis identified >200 differentially expressed genes involved in stem growth, cell wall biology, and sucrose accumulation. Genes encoding expansins and xyloglucan endotransglucosylase/hydrolases were differentially expressed in growing stem internodes. Genes encoding enzymes involved in the synthesis of cellulose, lignin, and glucuronoarabinoxylan were expressed at elevated levels in stems until approximately 7 days before anthesis and then down-regulated. CESA genes involved in primary and secondary cell wall synthesis showed different temporal patterns of expression. Following floral initiation, the level of sucrose and other non-structural carbohydrates increased to approximately 50% of the stem's dry weight. Stem sucrose accumulation was inversely correlated with >100-fold down-regulation of SbVIN1, a gene encoding a vacuolar invertase. Accumulation of stem sucrose was also correlated with cessation of leaf and stem growth at anthesis, decreased expression of genes involved in stem cell wall synthesis, and approximately 10-fold lower expression of SbSUS4, a gene encoding sucrose synthase that generates UDP-glucose from sucrose for cell wall biosynthesis. Genes for mixed linkage glucan synthesis (CSLF) and turnover were expressed at high levels in stems throughout development. Overall, the stem transcription profile resource and the genes and regulatory dynamics identified in this study will be useful for engineering sorghum stem composition for improved conversion to biofuels and bio-products. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

A randomized trial of high-dairy-protein, variable-carbohydrate diets and exercise on body composition in adults with obesity.

PubMed

Parr, Evelyn B; Coffey, Vernon G; Cato, Louise E; Phillips, Stuart M; Burke, Louise M; Hawley, John A

2016-05-01

This study determined the effects of 16-week high-dairy-protein, variable-carbohydrate (CHO) diets and exercise training (EXT) on body composition in men and women with overweight/obesity. One hundred and eleven participants (age 47 ± 6 years, body mass 90.9 ± 11.7 kg, BMI 33 ± 4 kg/m(2) , values mean ± SD) were randomly stratified to diets with either: high dairy protein, moderate CHO (40% CHO: 30% protein: 30% fat; ∼4 dairy servings); high dairy protein, high CHO (55%: 30%: 15%; ∼4 dairy servings); or control (55%: 15%: 30%; ∼1 dairy serving). Energy restriction (500 kcal/day) was achieved through diet (∼250 kcal/day) and EXT (∼250 kcal/day). Body composition was measured using dual-energy X-ray absorptiometry before, midway, and upon completion of the intervention. Eighty-nine (25 M/64 F) of 115 participants completed the 16-week intervention, losing 7.7 ± 3.2 kg fat mass (P < 0.001) and gaining 0.50 ± 1.75 kg lean mass (P < 0.01). There was no difference in the changes in body composition (fat mass or lean mass) between groups. Compared to a healthy control diet, energy-restricted high-protein diets containing different proportions of fat and CHO confer no advantage to weight loss or change in body composition in the presence of an appropriate exercise stimulus. © 2016 The Obesity Society.

Aligned Single Wall Carbon Nanotube Polymer Composites Using an Electric Field

NASA Technical Reports Server (NTRS)

Park, Cheol; Wiklinson, John; Banda, Sumanth; Ounaies, Zoubeida; Wise, Kristopher E.; Sauti, Godfrey; Lillehei, Peter T.; Harrison, Joycelyn S.

2005-01-01

While high shear alignment has been shown to improve the mechanical properties of single wall carbon nanotubes (SWNT)-polymer composites, it is difficult to control and often results in degradation of the electrical and dielectric properties of the composite. Here, we report a novel method to actively align SWNTs in a polymer matrix, which allows for control over the degree of alignment of SWNTs without the side effects of shear alignment. In this process, SWNTs are aligned via field-induced dipolar interactions among the nanotubes under an AC electric field in a liquid matrix followed by immobilization by photopolymerization while maintaining the electric field. Alignment of SWNTs was controlled as a function of magnitude, frequency, and application time of the applied electric field. The degree of SWNT alignment was assessed using optical microscopy and polarized Raman spectroscopy and the morphology of the aligned nanocomposites was investigated by high resolution scanning electron microscopy. The structure of the field induced aligned SWNTs is intrinsically different from that of shear aligned SWNTs. In the present work, SWNTs are not only aligned along the field, but also migrate laterally to form thick, aligned SWNT percolative columns between the electrodes. The actively aligned SWNTs amplify the electrical and dielectric properties in addition to improving the mechanical properties of the composite. All of these properties of the aligned nanocomposites exhibited anisotropic characteristics, which were controllable by tuning the applied field conditions.

Characterization of a feruloyl esterase from Aspergillus terreus facilitates the division of fungal enzymes from Carbohydrate Esterase family 1 of the carbohydrate-active enzymes (CAZy) database.

PubMed

Mäkelä, Miia R; Dilokpimol, Adiphol; Koskela, Salla M; Kuuskeri, Jaana; de Vries, Ronald P; Hildén, Kristiina

2018-04-26

Feruloyl esterases (FAEs) are accessory enzymes for plant biomass degradation, which catalyse hydrolysis of carboxylic ester linkages between hydroxycinnamic acids and plant cell-wall carbohydrates. They are a diverse group of enzymes evolved from, e.g. acetyl xylan esterases (AXEs), lipases and tannases, thus complicating their classification and prediction of function by sequence similarity. Recently, an increasing number of fungal FAEs have been biochemically characterized, owing to their potential in various biotechnological applications and multitude of candidate FAEs in fungal genomes. However, only part of the fungal FAEs are included in Carbohydrate Esterase family 1 (CE1) of the carbohydrate-active enzymes (CAZy) database. In this work, we performed a phylogenetic analysis that divided the fungal members of CE1 into five subfamilies of which three contained characterized enzymes with conserved activities. Conservation within one of the subfamilies was confirmed by characterization of an additional CE1 enzyme from Aspergillus terreus. Recombinant A. terreus FaeD (AtFaeD) showed broad specificity towards synthetic methyl and ethyl esters, and released ferulic acid from plant biomass substrates, demonstrating its true FAE activity and interesting features as potential biocatalyst. The subfamily division of the fungal CE1 members enables more efficient selection of candidate enzymes for biotechnological processes. © 2018 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Atkins and other low-carbohydrate diets: hoax or an effective tool for weight loss?

PubMed

Astrup, Arne; Meinert Larsen, Thomas; Harper, Angela

The Atkins diet books have sold more than 45 million copies over 40 years, and in the obesity epidemic this diet and accompanying Atkins food products are popular. The diet claims to be effective at producing weight loss despite ad-libitum consumption of fatty meat, butter, and other high-fat dairy products, restricting only the intake of carbohydrates to under 30 g a day. Low-carbohydrate diets have been regarded as fad diets, but recent research questions this view. A systematic review of low-carbohydrate diets found that the weight loss achieved is associated with the duration of the diet and restriction of energy intake, but not with restriction of carbohydrates. Two groups have reported longer-term randomised studies that compared instruction in the low-carbohydrate diet with a low-fat calorie-reduced diet in obese patients (N Engl J Med 2003; 348: 2082-90; Ann Intern Med 2004; 140: 778-85). Both trials showed better weight loss on the low-carbohydrate diet after 6 months, but no difference after 12 months. WHERE NEXT?: The apparent paradox that ad-libitum intake of high-fat foods produces weight loss might be due to severe restriction of carbohydrate depleting glycogen stores, leading to excretion of bound water, the ketogenic nature of the diet being appetite suppressing, the high protein-content being highly satiating and reducing spontaneous food intake, or limited food choices leading to decreased energy intake. Long-term studies are needed to measure changes in nutritional status and body composition during the low-carbohydrate diet, and to assess fasting and postprandial cardiovascular risk factors and adverse effects. Without that information, low-carbohydrate diets cannot be recommended.

Characterization of mechanical properties of hydroxyapatite-silicon-multi walled carbon nano tubes composite coatings synthesized by EPD on NiTi alloys for biomedical application.

PubMed

Khalili, Vida; Khalil-Allafi, Jafar; Sengstock, Christina; Motemani, Yahya; Paulsen, Alexander; Frenzel, Jan; Eggeler, Gunther; Köller, Manfred

2016-06-01

Release of Ni(1+) ions from NiTi alloy into tissue environment, biological response on the surface of NiTi and the allergic reaction of atopic people towards Ni are challengeable issues for biomedical application. In this study, composite coatings of hydroxyapatite-silicon multi walled carbon nano-tubes with 20wt% Silicon and 1wt% multi walled carbon nano-tubes of HA were deposited on a NiTi substrate using electrophoretic methods. The SEM images of coated samples exhibit a continuous and compact morphology for hydroxyapatite-silicon and hydroxyapatite-silicon-multi walled carbon nano-tubes coatings. Nano-indentation analysis on different locations of coatings represents the highest elastic modulus (45.8GPa) for HA-Si-MWCNTs which is between the elastic modulus of NiTi substrate (66.5GPa) and bone tissue (≈30GPa). This results in decrease of stress gradient on coating-substrate-bone interfaces during performance. The results of nano-scratch analysis show the highest critical distance of delamination (2.5mm) and normal load before failure (837mN) as well as highest critical contact pressure for hydroxyapatite-silicon-multi walled carbon nano-tubes coating. The cell culture results show that human mesenchymal stem cells are able to adhere and proliferate on the pure hydroxyapatite and composite coatings. The presence of both silicon and multi walled carbon nano-tubes (CS3) in the hydroxyapatite coating induce more adherence of viable human mesenchymal stem cells in contrast to the HA coated samples with only silicon (CS2). These results make hydroxyapatite-silicon-multi walled carbon nano-tubes a promising composite coating for future bone implant application. Copyright © 2016 Elsevier Ltd. All rights reserved.

Exponential increase in postprandial blood-glucose exposure with increasing carbohydrate loads using a linear carbohydrate-to-insulin ratio.

PubMed

Marran, K J; Davey, B; Lang, A; Segal, D G

2013-04-10

Postprandial glucose excursions contribute significantly to average blood glucose, glycaemic variability and cardiovascular risk. Carbohydrate counting is a method of insulin dosing that balances carbohydrate load to insulin dose using a fixed ratio. Many patients and current insulin pumps calculate insulin delivery for meals based on a linear carbohydrate-to-insulin relationship. It is our hypothesis that a non-linear relationship exists between the amounts of carbohydrate consumed and the insulin required to cover it. To document blood glucose exposure in response to increasing carbohydrate loads on fixed carbohydrate-to-insulin ratios. Five type 1 diabetic subjects receiving insulin pump therapy with good control were recruited. Morning basal rates and carbohydrate- to-insulin ratios were optimised. A Medtronic glucose sensor was used for 5 days to collect data for area-under-the-curve (AUC) analysis, during which standardised meals of increasing carbohydrate loads were consumed. Increasing carbohydrate loads using a fixed carbohydrate-to-insulin ratio resulted in increasing glucose AUC. The relationship was found to be exponential rather than linear. Late postprandial hypoglycaemia followed carbohydrate loads of >60 g and this was often followed by rebound hyperglycaemia that lasted >6 hours. A non-linear relationship exists between carbohydrates consumed and the insulin required to cover them. This has implications for control of postprandial blood sugars, especially when consuming large carbohydrate loads. Further studies are required to look at the optimal ratios, duration and type of insulin boluses required to cover increasing carbohydrate loads.

Effects of a plant-based high-carbohydrate/high-fiber diet versus high-monounsaturated fat/low-carbohydrate diet on postprandial lipids in type 2 diabetic patients.

PubMed

De Natale, Claudia; Annuzzi, Giovanni; Bozzetto, Lutgarda; Mazzarella, Raffaella; Costabile, Giuseppina; Ciano, Ornella; Riccardi, Gabriele; Rivellese, Angela A

2009-12-01

To search for a better dietary approach to treat postprandial lipid abnormalities and improve glucose control in type 2 diabetic patients. According to a randomized crossover design, 18 type 2 diabetic patients (aged 59 +/- 5 years; BMI 27 +/- 3 kg/m(2)) (means +/- SD) in satisfactory blood glucose control on diet or diet plus metformin followed a diet relatively rich in carbohydrates (52% total energy), rich in fiber (28 g/1,000 kcal), and with a low glycemic index (58%) (high-carbohydrate/high-fiber diet) or a diet relatively low in carbohydrate (45%) and rich in monounsaturated fat (23%) (low-carbohydrate/high-monounsaturated fat diet) for 4 weeks. Thereafter, they shifted to the other diet for 4 more weeks. At the end of each period, plasma glucose, insulin, lipids, and lipoprotein fractions (separated by discontinuous density gradient ultracentrifugation) were determined on blood samples taken at fasting and over 6 h after a test meal having a similar composition as the corresponding diet. In addition to a significant decrease in postprandial plasma glucose, insulin responses, and glycemic variability, the high-carbohydrate/high-fiber diet also significantly improved the primary end point, since it reduced the postprandial incremental areas under the curve (IAUCs) of triglyceride-rich lipoproteins, in particular, chylomicrons (cholesterol IAUC: 0.05 +/- 0.01 vs. 0.08 +/- 0.02 mmol/l per 6 h; triglycerides IAUC: 0.71 +/- 0.35 vs. 1.03 +/- 0.58 mmol/l per 6 h, P < 0.05). A diet rich in carbohydrate and fiber, essentially based on legumes, vegetables, fruits, and whole cereals, may be particularly useful for treating diabetic patients because of its multiple effects on different cardiovascular risk factors, including postprandial lipids abnormalities.

Facile preparation and electrochemical characterization of cobalt oxide/multi-walled carbon nanotube composites for supercapacitors

NASA Astrophysics Data System (ADS)

Lang, Junwei; Yan, Xingbin; Xue, Qunji

A series of cobalt oxide/multi-walled carbon nanotube (Co 3O 4/MWCNT) composites are successfully synthesized by a facile chemical co-precipitation method followed by a simple thermal treatment process. The morphology and structure of as-obtained composites are characterized by X-ray diffraction, scanning electron microscopy, and N 2-adsorption/desorption measurements, and the electrochemical properties are investigated by cyclic voltammetry (CV), galvanostatic charge/discharge and electrochemical impedance spectroscopy (EIS). For all Co 3O 4/MWCNT composites, MWCNTs are well dispersed in the loosely packed Co 3O 4 nanoparticles. Among them, the Co 3O 4-5%MWCNT composite exhibits the highest specific surface area of 137 m 2 g -1 and a mesoporous structure with a narrow distribution of pore size from 2 to 10 nm. Because of the synergistic effects coming from Co 3O 4 nanoparticles and MWCNTs, the electrochemical performances of pure Co 3O 4 material are significantly improved after adding MWCNTs. The Co 3O 4-5%MWCNT composite shows the largest specific capacitance of 418 F g -1 at a current density of 0.625 A g -1 in 2 M KOH electrolyte. Furthermore, this composite exhibits good cycling stability and lifetime. Therefore, based on the above investigation, such Co 3O 4/MWCNT composite could be a potential candidate for supercapacitors.

[Performance enhancement by carbohydrate intake during sport: effects of carbohydrates during and after high-intensity exercise].

PubMed

Beelen, Milou; Cermak, Naomi M; van Loon, Luc J C

2015-01-01

Endogenous carbohydrate availability does not provide sufficient energy for prolonged moderate to high-intensity exercise. Carbohydrate ingestion during high-intensity exercise can therefore enhance performance.- For exercise lasting 1 to 2.5 hours, athletes are advised to ingest 30-60 g of carbohydrates per hour.- Well-trained endurance athletes competing for longer than 2.5 hours at high intensity can metabolise up to 90 g of carbohydrates per hour, provided that a mixture of glucose and fructose is ingested.- Athletes participating in intermittent or team sports are advised to follow the same strategies but the timing of carbohydrate intake depends on the type of sport.- If top performance is required again within 24 hours after strenuous exercise, the advice is to supplement endogenous carbohydrate supplies quickly within the first few hours post-exercise by ingesting large amounts of carbohydrate (1.2 g/kg/h) or a lower amount of carbohydrate (0.8 g/kg/h) with a small amount of protein (0.2-0.4 g/kg/h).

Radioiodinated branched carbohydrates

DOEpatents

Goodman, Mark M.; Knapp, Jr., Furn F.

1989-01-01

A radioiodinated branched carbohydrate for tissue imaging. Iodine-123 is stabilized in the compound by attaching it to a vinyl functional group that is on the carbohydrate. The compound exhibits good uptake and retention and is promising in the development of radiopharmaceuticals for brain, heart and tumor imaging.

Cats and Carbohydrates: The Carnivore Fantasy?

PubMed Central

Verbrugghe, Adronie; Hesta, Myriam

2017-01-01

The domestic cat’s wild ancestors are obligate carnivores that consume prey containing only minimal amounts of carbohydrates. Evolutionary events adapted the cat’s metabolism and physiology to this diet strictly composed of animal tissues and led to unique digestive and metabolic peculiarities of carbohydrate metabolism. The domestic cat still closely resembles its wild ancestor. Although the carnivore connection of domestic cats is well recognised, little is known about the precise nutrient profile to which the digestive physiology and metabolism of the cat have adapted throughout evolution. Moreover, studies show that domestic cats balance macronutrient intake by selecting low-carbohydrate foods. The fact that cats evolved consuming low-carbohydrate prey has led to speculations that high-carbohydrate diets could be detrimental for a cat’s health. More specifically, it has been suggested that excess carbohydrates could lead to feline obesity and diabetes mellitus. Additionally, the chances for remission of diabetes mellitus are higher in cats that consume a low-carbohydrate diet. This literature review will summarise current carbohydrate knowledge pertaining to digestion, absorption and metabolism of carbohydrates, food selection and macronutrient balancing in healthy, obese and diabetic cats, as well as the role of carbohydrates in prevention and treatment of obesity and diabetes mellitus. PMID:29140289

Characterization of the carbohydrate components of Taenia solium oncosphere proteins and their role in the antigenicity.

PubMed

Arana, Yanina; Verastegui, Manuela; Tuero, Iskra; Grandjean, Louis; Garcia, Hector H; Gilman, Robert H

2013-10-01

This study examines the carbohydrate composition of Taenia solium whole oncosphere antigens (WOAs), in order to improve the understanding of the antigenicity of the T. solium. Better knowledge of oncosphere antigens is crucial to accurately diagnose previous exposure to T. solium eggs and thus predict the development of neurocysticercosis. A set of seven lectins conjugates with wide carbohydrate specificity were used on parasite fixations and somatic extracts. Lectin fluorescence revealed that D-mannose, D-glucose, D-galactose and N-acetyl-D-galactosamine residues were the most abundant constituents of carbohydrate chains on the surface of T. solium oncosphere. Lectin blotting showed that posttranslational modification with N-glycosylation was abundant while little evidence of O-linked carbohydrates was observed. Chemical oxidation and enzymatic deglycosylation in situ were performed to investigate the immunoreactivity of the carbohydrate moieties. Linearizing or removing the carbohydrate moieties from the protein backbones did not diminish the immunoreactivity of these antigens, suggesting that a substantial part of the host immune response against T. solium oncosphere is directed against the peptide epitopes on the parasite antigens. Finally, using carbohydrate probes, we demonstrated for the first time that the presence of several lectins on the surface of the oncosphere was specific to carbohydrates found in intestinal mucus, suggesting a possible role in initial attachment of the parasite to host cells.

CHARACTERIZATION OF THE CARBOHYDRATE COMPONENTS OF Taenia solium ONCOSPHERE PROTEINS AND THEIR ROLE IN THE ANTIGENICITY

PubMed Central

Arana, Yanina; Verastegui, Manuela; Tuero, Iskra; Grandjean, Louis; Garcia, Hector H.; Gilman, Robert H.

2015-01-01

This study examines the carbohydrate composition of Taenia solium whole oncosphere antigens (WOAs), in order to improve the understanding of the antigenicity of the T. solium. Better knowledge of oncosphere antigens is crucial to accurately diagnose previous exposure to T. solium eggs and thus predict the development of neurocysticercosis. A set of seven lectins conjugates with wide carbohydrate specificity were used on parasite fixations and somatic extracts. Lectin fluorescence revealed that D-mannose, D-glucose, D-galactose and N-acetyl-D-galactosamine residues were the most abundant constituents of carbohydrate chains on the surface of T. solium oncosphere. Lectin blotting showed that post-translational modification with N-glycosylation was abundant while little evidence of O-linked carbohydrates was observed. Chemical oxidation and enzymatic deglycosylation in situ were performed to investigate the immunoreactivity of the carbohydrate moieties. Linearizing or removing the carbohydrate moieties from the protein backbones did not diminish the immunoreactivity of these antigens, suggesting that a substantial part of the host immune response against T. solium oncosphere is directed against the peptide epitopes on the parasite antigens. Finally, using carbohydrate probes, we demonstrated for the first time that the presence of several lectins on the surface of the oncosphere was specific to carbohydrates found in intestinal mucus, suggesting a possible role in initial attachment of the parasite to host cells. PMID:23982308

Family 46 Carbohydrate-binding Modules Contribute to the Enzymatic Hydrolysis of Xyloglucan and β-1,3-1,4-Glucans through Distinct Mechanisms.

PubMed

Venditto, Immacolata; Najmudin, Shabir; Luís, Ana S; Ferreira, Luís M A; Sakka, Kazuo; Knox, J Paul; Gilbert, Harry J; Fontes, Carlos M G A

2015-04-24

Structural carbohydrates comprise an extraordinary source of energy that remains poorly utilized by the biofuel sector as enzymes have restricted access to their substrates within the intricacy of plant cell walls. Carbohydrate active enzymes (CAZYmes) that target recalcitrant polysaccharides are modular enzymes containing noncatalytic carbohydrate-binding modules (CBMs) that direct enzymes to their cognate substrate, thus potentiating catalysis. In general, CBMs are functionally and structurally autonomous from their associated catalytic domains from which they are separated through flexible linker sequences. Here, we show that a C-terminal CBM46 derived from BhCel5B, a Bacillus halodurans endoglucanase, does not interact with β-glucans independently but, uniquely, acts cooperatively with the catalytic domain of the enzyme in substrate recognition. The structure of BhCBM46 revealed a β-sandwich fold that abuts onto the region of the substrate binding cleft upstream of the active site. BhCBM46 as a discrete entity is unable to bind to β-glucans. Removal of BhCBM46 from BhCel5B, however, abrogates binding to β-1,3-1,4-glucans while substantially decreasing the affinity for decorated β-1,4-glucan homopolymers such as xyloglucan. The CBM46 was shown to contribute to xyloglucan hydrolysis only in the context of intact plant cell walls, but it potentiates enzymatic activity against purified β-1,3-1,4-glucans in solution or within the cell wall. This report reveals the mechanism by which a CBM can promote enzyme activity through direct interaction with the substrate or by targeting regions of the plant cell wall where the target glucan is abundant. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Development and application of new composite grouting material for sealing groundwater inflow and reinforcing wall rock in deep mine.

PubMed

Jinpeng, Zhang; Limin, Liu; Futao, Zhang; Junzhi, Cao

2018-04-04

With cement, bentonite, water glass, J85 accelerator, retarder and water as raw materials, a new composite grouting material used to seal groundwater inflow and reinforce wall rock in deep fractured rock mass was developed in this paper. Based on the reaction mechanism of raw material, the pumpable time, stone rate, initial setting time, plastic strength and unconfined compressive strength of multi-group proportion grouts were tested by orthogonal experiment. Then, the optimum proportion of composite grouting material was selected and applied to the grouting engineering for sealing groundwater inflow and reinforcing wall rock in mine shaft lining. The results show the mixing proportion of the maximum pumpable time, maximum stone rate and minimum initial setting time of grout are A K4 B K1 C K4 D K2 , A K3 B K1 C K1 D K4 and A K3 B K3 C K4 D K1 , respectively. The mixing proportion of the maximum plastic strength and unconfined compressive strength of grouts concretion bodies are A K1 B K1 C K1 D K3 and A K1 B K1 C K1 D K1 , respectively. Balanced the above 5 indicators overall and determined the optimum proportion of grouts: bentonite-cement ratio of 1.0, water-solid ratio of 3.5, accelerator content of 2.9% and retarder content of 1.45%. This new composite grouting material had good effect on the grouting engineering for sealing groundwater inflow and reinforcing wall rock in deep fractured rock mass.

Biocompatibility of single-walled carbon nanotube composites for bone regeneration.

PubMed

Gupta, A; Liberati, T A; Verhulst, S J; Main, B J; Roberts, M H; Potty, A G R; Pylawka, T K; El-Amin Iii, S F

2015-05-01

The purpose of this study was to evaluate in vivo biocompatibility of novel single-walled carbon nanotubes (SWCNT)/poly(lactic-co-glycolic acid) (PLAGA) composites for applications in bone and tissue regeneration. A total of 60 Sprague-Dawley rats (125 g to 149 g) were implanted subcutaneously with SWCNT/PLAGA composites (10 mg SWCNT and 1gm PLAGA 12 mm diameter two-dimensional disks), and at two, four, eight and 12 weeks post-implantation were compared with control (Sham) and PLAGA (five rats per group/point in time). Rats were observed for signs of morbidity, overt toxicity, weight gain and food consumption, while haematology, urinalysis and histopathology were completed when the animals were killed. No mortality and clinical signs were observed. All groups showed consistent weight gain, and the rate of gain for each group was similar. All groups exhibited a similar pattern for food consumption. No difference in urinalysis, haematology, and absolute and relative organ weight was observed. A mild to moderate increase in the summary toxicity (sumtox) score was observed for PLAGA and SWCNT/PLAGA implanted animals, whereas the control animals did not show any response. Both PLAGA and SWCNT/PLAGA showed a significantly higher sumtox score compared with the control group at all time intervals. However, there was no significant difference between PLAGA and SWCNT/PLAGA groups. Our results demonstrate that SWCNT/PLAGA composites exhibited in vivo biocompatibility similar to the Food and Drug Administration approved biocompatible polymer, PLAGA, over a period of 12 weeks. These results showed potential of SWCNT/PLAGA composites for bone regeneration as the low percentage of SWCNT did not elicit a localised or general overt toxicity. Following the 12-week exposure, the material was considered to have an acceptable biocompatibility to warrant further long-term and more invasive in vivo studies. Cite this article: Bone Joint Res 2015;4:70-7. ©2015 The British Editorial

Biocompatibility of single-walled carbon nanotube composites for bone regeneration

PubMed Central

Gupta, A.; Liberati, T. A.; Verhulst, S. J.; Main, B. J.; Roberts, M. H.; Potty, A. G. R.; Pylawka, T. K.; El-Amin III, S. F.

2015-01-01

Objectives The purpose of this study was to evaluate in vivo biocompatibility of novel single-walled carbon nanotubes (SWCNT)/poly(lactic-co-glycolic acid) (PLAGA) composites for applications in bone and tissue regeneration. Methods A total of 60 Sprague-Dawley rats (125 g to 149 g) were implanted subcutaneously with SWCNT/PLAGA composites (10 mg SWCNT and 1gm PLAGA 12 mm diameter two-dimensional disks), and at two, four, eight and 12 weeks post-implantation were compared with control (Sham) and PLAGA (five rats per group/point in time). Rats were observed for signs of morbidity, overt toxicity, weight gain and food consumption, while haematology, urinalysis and histopathology were completed when the animals were killed. Results No mortality and clinical signs were observed. All groups showed consistent weight gain, and the rate of gain for each group was similar. All groups exhibited a similar pattern for food consumption. No difference in urinalysis, haematology, and absolute and relative organ weight was observed. A mild to moderate increase in the summary toxicity (sumtox) score was observed for PLAGA and SWCNT/PLAGA implanted animals, whereas the control animals did not show any response. Both PLAGA and SWCNT/PLAGA showed a significantly higher sumtox score compared with the control group at all time intervals. However, there was no significant difference between PLAGA and SWCNT/PLAGA groups. Conclusions Our results demonstrate that SWCNT/PLAGA composites exhibited in vivo biocompatibility similar to the Food and Drug Administration approved biocompatible polymer, PLAGA, over a period of 12 weeks. These results showed potential of SWCNT/PLAGA composites for bone regeneration as the low percentage of SWCNT did not elicit a localised or general overt toxicity. Following the 12-week exposure, the material was considered to have an acceptable biocompatibility to warrant further long-term and more invasive in vivo studies. Cite this article: Bone Joint Res 2015

Stearoyl-CoA Desaturase and its Relation to High-Carbohydrate Diets and Obesity

PubMed Central

Flowers, Matthew T.; Ntambi, James M.

2009-01-01

Obesity is currently a worldwide epidemic and public health burden that increases the risk for developing insulin resistance and several chronic diseases such as diabetes, cardiovascular diseases and non-alcoholic fatty liver disease. The multifactorial causes of obesity include several genetic, dietary and lifestyle variables that together result in an imbalance between energy intake and energy expenditure. Dietary approaches to limit fat intake are commonly prescribed to achieve the hypocaloric conditions necessary for weight loss. But dietary fat restriction is often accompanied by increased carbohydrate intake, which can dramatically increase endogenous fatty acid synthesis depending upon carbohydrate composition. Since both dietary and endogenously synthesized fatty acids contribute to the whole-body fatty acid pool, obesity can therefore result from excessive fat or carbohydrate consumption. Stearoyl-Coenzyme A desaturase-1 (SCD1) is a delta-9 fatty acid desaturase that converts saturated fatty acids into monounsaturated fatty acids (MUFA) and this activity is elevated by dietary carbohydrate. Mice lacking Scd1 are protected from obesity and insulin resistance and are characterized by decreased fatty acid synthesis and increased fatty acid oxidation. In this review, we address the association of high-carbohydrate diets with increased SCD activity and summarize the current literature on the subject of SCD1 and body weight regulation. PMID:19166967

Micro/Nanomechanical characterization of multi-walled carbon nanotubes reinforced epoxy composite.

PubMed

Cui, Peng; Wang, Xinnan; Tangpong, X W

2012-11-01

In this paper, the mechanical properties of 1 wt.% multi-walled carbon nanotubes (MWCNTs) reinforced epoxy nanocomposites were characterized using a self-designed micro/nano three point bending tester that was on an atomic force microscope (AFM) to in situ observe MWCNTs movement on the sample surface under loading. The migration of an individual MWCNT at the surface of the nanocomposite was tracked to address the nanomechanical reinforcing mechanism of the nanocomposites. Through morphology analysis of the nanocomposite via scanning electron microscopy, AFM, and digital image correlation technique, it was found that the MWCNTs agglomerate and the bundles were the main factors for limiting the bending strength of the composites. The agglomeration/bundle effect was included in the Halpin-Tsai model to account for the elastic modulus of the nanocomposites.

The influence of Mediterranean, carbohydrate and high protein diets on gut microbiota composition in the treatment of obesity and associated inflammatory state.

PubMed

Lopez-Legarrea, Patricia; Fuller, Nicholas Robert; Zulet, María Angeles; Martinez, Jose Alfredo; Caterson, Ian Douglas

2014-01-01

The role of the gut microbiota in understanding the onset and development of obesity is gaining importance. Dietary strategies are the main tool employed to counteract obesity, and nowadays they are focused on a wide range of different aspects of diet and not only on calorie restriction. Additionally, diet is known to be a major factor influencing modification of the gut microbiota. Therefore the influence of both macronutrient and micronutrient content of any dietary strategy to treat obesity on gut bacterial composition should now be taken into consideration, in addition to energy restriction. This review aims to collect the available data regarding the influence of different dietary components on gut microbiota in relation to obesity and inflammatory states in humans. Although more work is needed, specific dietary factors (carbohydrate, protein and Mediterranean foods) have been shown to have an influence on the gut microbiome composition, meaning that there is an opportunity to prevent and treat obesity based on microbiota outcomes.

Defect Characterization in a Thin Walled Composite RP-1 Tank: A Case Study

NASA Technical Reports Server (NTRS)

Langsing, Matthew D.; Walker, James L., II; Russell, Samual S.

2000-01-01

A full scale thin walled composite tank, designed and fabricated for the storage of pressurized RP- I rocket fuel, was fully inspected with digital infrared thermography (IR) during assembly and prior to proof testing. The tank featured a "pill capsule" design with the equatorial bondline being overwrapped on both the inner and outer surfaces. A composite skirt was bonded to the aft dome of the tank to serve as a structural support when the tank was stood on end in service. Numerous anomalies were detected and mapped prior to proof testing, some along bondlines and some scattered throughout the acreage. After the tank was intentionally burst, coupons were cut from the regions including thermographic anomalies. These coupons were again inspected thermographically to document the growth of any indications due to proof testing. Ultrasonic inspections (UT) were also performed on the coupons for comparison to thermography. Several coupons were dissected and micrographed. Relationships between IR and UT indications and the physical nature of the dissected material are presented.

A cell wall-degrading esterase of Xanthomonas oryzae requires a unique substrate recognition module for pathogenesis on rice.

PubMed

Aparna, Gudlur; Chatterjee, Avradip; Sonti, Ramesh V; Sankaranarayanan, Rajan

2009-06-01

Xanthomonas oryzae pv oryzae (Xoo) causes bacterial blight, a serious disease of rice (Oryza sativa). LipA is a secretory virulence factor of Xoo, implicated in degradation of rice cell walls and the concomitant elicitation of innate immune responses, such as callose deposition and programmed cell death. Here, we present the high-resolution structural characterization of LipA that reveals an all-helical ligand binding module as a distinct functional attachment to the canonical hydrolase catalytic domain. We demonstrate that the enzyme binds to a glycoside ligand through a rigid pocket comprising distinct carbohydrate-specific and acyl chain recognition sites where the catalytic triad is situated 15 A from the anchored carbohydrate. Point mutations disrupting the carbohydrate anchor site or blocking the pocket, even at a considerable distance from the enzyme active site, can abrogate in planta LipA function, exemplified by loss of both virulence and the ability to elicit host defense responses. A high conservation of the module across genus Xanthomonas emphasizes the significance of this unique plant cell wall-degrading function for this important group of plant pathogenic bacteria. A comparison with the related structural families illustrates how a typical lipase is recruited to act on plant cell walls to promote virulence, thus providing a remarkable example of the emergence of novel functions around existing scaffolds for increased proficiency of pathogenesis during pathogen-plant coevolution.

Changes in Cell Wall Polysaccharides Associated With Growth 1

PubMed Central

Nevins, Donald J.; English, Patricia D.; Albersheim, Peter

1968-01-01

Changes in the polysaccharide composition of Phaseolus vulgaris, P. aureus, and Zea mays cell walls were studied during the first 28 days of seedling development using a gas chromatographic method for the analysis of neutral sugars. Acid hydrolysis of cell wall material from young tissues liberates rhamnose, fucose, arabinose, xylose, mannose, galactose, and glucose which collectively can account for as much as 70% of the dry weight of the wall. Mature walls in fully expanded tissues of these same plants contain less of these constituents (10%-20% of dry wt). Gross differences are observed between developmental patterns of the cell wall in the various parts of a seedling, such as root, stem, and leaf. The general patterns of wall polysaccharide composition change, however, are similar for analogous organs among the varieties of a species. Small but significant differences in the rates of change in sugar composition were detected between varieties of the same species which exhibited different growth patterns. The cell walls of species which are further removed phylogenetically exhibit even more dissimilar developmental patterns. The results demonstrate the dynamic nature of the cell wall during growth as well as the quantitative and qualitative exactness with which the biosynthesis of plant cell walls is regulated. PMID:16656862

Effect of dietary levels of lipid and carbohydrate on growth performance, body composition, nitrogen excretion and plasma glucose levels in rainbow trout reared at 8 or 18 degrees C.

PubMed

Brauge, C; Corraze, G; Médale, F

1995-01-01

Trout reared at 8 or 18 degrees C were fed twice a day almost to satiation with 1 of 3 experimental diets. The diets were formulated to contain the same levels of protein (43%, dry matter (DM) basis) and digestible energy (around 15 kJ/g DM), but different carbohydrate/lipid ratios 30:7 to 23:14). Time-course studies of nitrogen excretion and glycaemia were also carried out. After 12 weeks of feeding, growth, protein retention and body composition were not influenced by the dietary treatment in trout reared at 8 degrees C. At 18 degrees C, the protein retention was not affected by dietary treatment, but the weight gain tended to be higher in trout fed the diet with the lowest carbohydrate/lipid ratio. This result was due to higher body lipid deposition in these trout. Nitrogen excretion was not influenced by dietary treatment, but was higher at 18 degrees C than at 8 degrees C because of a higher feed intake. Glycaemia increased with dietary level of digestible carbohydrate and the highest plasma glucose level was attained later at 8 degrees C in comparison to 18 degrees C.

Analysis of Carbohydrate and Fatty Acid Marker Abundance in Ricin Toxin Preparations for Forensic Information

DOE Office of Scientific and Technical Information (OSTI.GOV)

Colburn, Heather A.; Wunschel, David S.; Kreuzer-Martin, Helen W.

2010-07-15

One challenge in the forensic analysis of ricin samples is determining the method and extent of sample preparation. Ricin purification from the source castor seeds is essentially a protein purification through removal of the non-protein fractions of the seed. Two major, non-protein constituents in the seed are the castor oil and carbohydrates. Ricinoleic acid is a relatively unique fatty acid in nature and is the most abundant component of castor oil, which comprises roughly half the seed weight. The carbohydrate component comprises roughly half of the remaining “mash” left after oil and hull removal. We used derivatization of carbohydrate andmore » fatty acid markers followed by identification and quantification using gas chromatography/mass spectrometry (GC/MS) to assess compositional changes in ricin samples purified by different methods. The loss of ricinoleic acid indicated steps for oil removal had occurred. Changes to the carbohydrate content of the sample were also observed following protein precipitation. The differential loss of arabinose relative to mannose indicated removal of the major carbohydrate fraction of the seed and enrichment of the protein content. Taken together, these changes in fatty acid and carbohydrate abundance are indicative of the preparation method used for each sample.« less

Carbohydrate utilization and the lager yeast transcriptome during brewery fermentation.

PubMed

Gibson, Brian R; Boulton, Chris A; Box, Wendy G; Graham, Neil S; Lawrence, Stephen J; Linforth, Robert S T; Smart, Katherine A

2008-08-01

The fermentable carbohydrate composition of wort and the manner in which it is utilized by yeast during brewery fermentation have a direct influence on fermentation efficiency and quality of the final product. In this study the response of a brewing yeast strain to changes in wort fermentable carbohydrate concentration and composition during full-scale (3275 hl) brewery fermentation was investigated by measuring transcriptome changes with the aid of oligonucleotide-based DNA arrays. Up to 74% of the detectable genes showed a significant (p

A systematic study of chemogenomics of carbohydrates.

PubMed

Gu, Jiangyong; Luo, Fang; Chen, Lirong; Yuan, Gu; Xu, Xiaojie

2014-03-04

Chemogenomics focuses on the interactions between biologically active molecules and protein targets for drug discovery. Carbohydrates are the most abundant compounds in natural products. Compared with other drugs, the carbohydrate drugs show weaker side effects. Searching for multi-target carbohydrate drugs can be regarded as a solution to improve therapeutic efficacy and safety. In this work, we collected 60 344 carbohydrates from the Universal Natural Products Database (UNPD) and explored the chemical space of carbohydrates by principal component analysis. We found that there is a large quantity of potential lead compounds among carbohydrates. Then we explored the potential of carbohydrates in drug discovery by using a network-based multi-target computational approach. All carbohydrates were docked to 2389 target proteins. The most potential carbohydrates for drug discovery and their indications were predicted based on a docking score-weighted prediction model. We also explored the interactions between carbohydrates and target proteins to find the pathological networks, potential drug candidates and new indications.

Benefits and hazards of dietary carbohydrate.

PubMed

Connor, William E; Duell, P Barton; Connor, Sonja L

2005-11-01

Since the dawn of civilization, carbohydrate has comprised the largest source of energy in the diet for most populations. The source of the carbohydrate has been from plants in the form of complex carbohydrate high in fiber. Only in affluent cultures has sugar contributed so much of the total energy. When carbohydrate is consumed as a major component of a plant-based diet, a high-carbohydrate, low-fat diet is associated with low plasma levels of total and low-density lipoprotein cholesterol, less coronary heart disease, less diabetes, and less obesity. Very low-carbohydrate (ketogenic) diets may provide short-term solutions but do not lead to a long-term solution for most people.

Renewable Hydrogen Carrier - Carbohydrate: Constructing the Carbon-Neutral Carbohydrate Economy

DTIC Science & Technology

2011-01-31

temperature. High fructose corn syrup , low-cost sucrose replacement, is made by stabilized glucose isomerase, which can work at ~60 °C for even about two...sustainable production, high -density storage, costly infrastructure, to eliminating safety concern. The use of renewable carbohydrate as a high -density...100% selectivity of enzymes, modest reaction conditions, and high -purity of generated hydrogen, carbohydrate is a promising hydrogen carrier for end

Electrochemical Determination of Pentachlorophenol in Water on a Multi-Wall Carbon Nanotubes-Epoxy Composite Electrode

PubMed Central

Remes, Adriana; Pop, Aniela; Manea, Florica; Baciu, Anamaria; Picken, Stephen J.; Schoonman, Joop

2012-01-01

The aim of this study was the preparation, characterization, and application of a multi-wall carbon nanotubes-epoxy composite electrode (MWCNT-EP) with 25%, wt. MWCNTs loading for the voltammetric/amperometric determination of pentachlorophenol (PCP) in aqueous solutions. The structural and morphological aspects of the MWCNT-EP composite electrode were examined by scanning electron microscopy. The electrical properties were characterized by direct-current conductivity measurements in relation with the percolation threshold. The electrochemical behavior of PCP at the MWCNT-EP composite electrode was investigated using cyclic voltammetry in 0.1 M Na2SO4 supporting electrolyte in order to establish the parameters for amperometric/voltammetric determination of PCP. The linear dependence of current vs. PCP concentrations was reached in a wide concentration range from 0.2 to 12 μM PCP using cyclic voltammetry, differential-pulsed voltammetry, square-wave voltammetry, chronoamperometry, and multiple-pulsed amperometry techniques. The best electroanalytical performances of this composite electrode were achieved using a pre-concentration/square-wave voltammetric technique and also multiple-pulsed amperometry techniques envisaging the practical applications. The ease of preparation, high sensitivity, and stability of this composite electrode should open novel avenues and applications for fabricating robust sensors for detection of many important species. PMID:22969335

Comparison of mechanical properties of multi-walled carbon nanotube and graphene nanosheet/polyethylene oxide composites plasticized with lithium triflate

NASA Astrophysics Data System (ADS)

Jurkane, A.; Gaidukov, S.

2017-10-01

A strong engineering interest in nanostructured conducting polymers and its composite materials have been widely used to build various sensor devices, electronic interconnect devices, fuel cells and batteries. Preparation of polymeric nano-composites with finely controlled structure, especially, at nano-scale, is still one of the most perspective modification ways of the properties of polymeric composites. Multi-walled carbon nanotube (MWCNT)/polyethylene oxide (PEO) and graphene nanosheets (GR)/PEO composites and composite of MWCNT/GR/PEO were prepared by solution casting and hot-pressing method. Composites were plasticized by 5% of Lithium triflate (LiTrifl), which play role of additional ion source in conducting polymer composite. Mechanical tensile tests were performed to evaluate nanoparticles influence on the mechanical strength of the conductive polymer composite materials. Difference of tensile tests of prepared composition can be seen from tensile tests data curves. The results of tensile tests indicated that the nanoparticles can provide PEO/5%LiTrifl composite with stiffening effects at rather low filler content (at least 0.05% by volume).

Architecture of dermatophyte cell Walls: Electron microscopic and biochemical analysis

NASA Technical Reports Server (NTRS)

Nozawa, Y.; Kitajima, Y.

1984-01-01

A review with 83 references on the cell wall structure of dermatophytes is presented. Topics discussed include separation and preparation of cell walls; microstructure of cell walls by electron microscopy; chemical composition of cell walls; structural model of cell walls; and morphological structure of cell walls.

Functional interaction analysis of GM1-related carbohydrates and Vibrio cholerae toxins using carbohydrate microarray.

PubMed

Kim, Chang Sup; Seo, Jeong Hyun; Cha, Hyung Joon

2012-08-07

The development of analytical tools is important for understanding the infection mechanisms of pathogenic bacteria or viruses. In the present work, a functional carbohydrate microarray combined with a fluorescence immunoassay was developed to analyze the interactions of Vibrio cholerae toxin (ctx) proteins and GM1-related carbohydrates. Ctx proteins were loaded onto the surface-immobilized GM1 pentasaccharide and six related carbohydrates, and their binding affinities were detected immunologically. The analysis of the ctx-carbohydrate interactions revealed that the intrinsic selectivity of ctx was GM1 pentasaccharide ≫ GM2 tetrasaccharide > asialo GM1 tetrasaccharide ≥ GM3trisaccharide, indicating that a two-finger grip formation and the terminal monosaccharides play important roles in the ctx-GM1 interaction. In addition, whole cholera toxin (ctxAB(5)) had a stricter substrate specificity and a stronger binding affinity than only the cholera toxin B subunit (ctxB). On the basis of the quantitative analysis, the carbohydrate microarray showed the sensitivity of detection of the ctxAB(5)-GM1 interaction with a limit-of-detection (LOD) of 2 ng mL(-1) (23 pM), which is comparable to other reported high sensitivity assay tools. In addition, the carbohydrate microarray successfully detected the actual toxin directly secreted from V. cholerae, without showing cross-reactivity to other bacteria. Collectively, these results demonstrate that the functional carbohydrate microarray is suitable for analyzing toxin protein-carbohydrate interactions and can be applied as a biosensor for toxin detection.

CH/π Interactions in Carbohydrate Recognition.

PubMed

Spiwok, Vojtěch

2017-06-23

Many carbohydrate-binding proteins contain aromatic amino acid residues in their binding sites. These residues interact with carbohydrates in a stacking geometry via CH/π interactions. These interactions can be found in carbohydrate-binding proteins, including lectins, enzymes and carbohydrate transporters. Besides this, many non-protein aromatic molecules (natural as well as artificial) can bind saccharides using these interactions. Recent computational and experimental studies have shown that carbohydrate-aromatic CH/π interactions are dispersion interactions, tuned by electrostatics and partially stabilized by a hydrophobic effect in solvated systems.

The importance of dietary carbohydrates.

PubMed

Sánchez-Castillo, Claudia P; Hudson, Geoffrey J; Englyst, Hans N; Dewey, Peter; James, W Philip T

2002-12-01

Forty years ago carbohydrates (CHO) were regarded as a simple energy source whereas they are now recognized as important food components. The human diet contains a wide range of CHO, the vast majority of which are of plant origin. Modern techniques based on chemical classification of dietary CHO replaced the traditional "by difference" measurement. They provide a logical basis for grouping into categories of specific nutritional importance. The physiological effects of dietary CHO are highly dependent on the rate and extent of digestion and absorption in the small intestine and fermentation in the large intestine, interactions which promote human health. Current knowledge of the fate of dietary CHO means that the potentially undesirable properties of many modern foods could be altered by using processing techniques that yield foods with more intact plant cell wall structures. Such products would more closely resemble the foods in the pre-agriculture diet with respect to the rate of digestion and absorption of CHO in the small intestine. The potentially detrimental physiological consequences of eating sugars and starch that are rapidly digested and absorbed in the small intestine suggest that, as fibre, the form, as well as the amount of starch should be considered. Increasing consumer awareness of the relationship between diet and health has led to demands for more widespread nutrition labelling. The entry "carbohydrate" is required in most countries, and the value is usually obtained "by difference" and used in the calculation of energy content. However, the value provides no nutritional information per se. Food labels should provide values that aid consumers in selecting a healthy diet.

Variations in abundance and size distribution of carbohydrates in the lower Mississippi River, Pearl River and Bay of St Louis

NASA Astrophysics Data System (ADS)

Wang, Xuri; Cai, Yihua; Guo, Laodong

2013-07-01

Riverine export of dissolved and particulate organic matter to the sea is one of the major components in marine carbon cycles, affecting biogeochemical processes in estuarine and coastal regions. However, the detailed composition of organic material and the relative partitioning among the dissolved, colloidal, and particulate phases are poorly quantified. The abundance of carbohydrate species and their partitioning among dissolved, colloidal, and particulate phases were examined in the waters from the lower Mississippi River (MR), the lower Pearl River (PR), and the Bay of St. Louis (BSL). Particulate carbohydrates (PCHO) represented a small fraction of the particulate organic carbon (POC) pool, with 4.7 ± 3.1%, 4.5 ± 2.4% and 1.8 ± 0.83% in the MR, PR, and BSL, respectively. Dissolved carbohydrates (DCHO) were a major component of the bulk dissolved organic carbon (DOC) pool, comprising 23%, 35%, and 18% in the MR, PR, and BSL, respectively. Differences in the DCHO/DOC ratio between the MR, PR, and BSL were related to their distinct characteristics in drainage basins, anthropogenic impacts, and hydrological conditions, reflecting differences in sources and composition of organic matter in different aquatic environments. Within the total carbohydrates (TCHO) pool, the high-molecular-weight carbohydrates (HMW-CHO, 1 kDa-0.45 μm) were the dominant species, representing 52-71% of the TCHO pool, followed by the low-molecular-weight carbohydrates (LMW-CHO, <1 kDa), representing 14-44% of the TCHO. The PCHO accounted for 4-16% of the bulk TCHO. Variations in the size distribution of carbohydrates among the MR, PR, and BSL were closely linked to the cycling pathway of organic matter and the interactions between different size fractions of the carbohydrates.

Nutritional and metabolic responses in common dentex (Dentex dentex) fed on different types and levels of carbohydrates.

PubMed

Pérez-Jiménez, Amalia; Abellán, Emilia; Arizcun, Marta; Cardenete, Gabriel; Morales, Amalia E; Hidalgo, M Carmen

2015-06-01

The present study was aimed to evaluate the capacity of common dentex (Dentex dentex) to efficiently use dietary carbohydrates. So, the effects of different type and levels of carbohydrates on growth performance, feed utilization, fish composition, plasma metabolites and key metabolic pathways in liver and white muscle of common dentex are presented. Nine isonitrogenous (43%) and isoenergetic (22 MJ kg(-1)) diets were formulated combining three types, pregelatinized starch (PS), dextrin (Dx) and maltodextrin (Mx), and three levels (12, 18 and 24%) of carbohydrates. Growth performance was not significantly influenced by treatments. The best feed utilization was observed in 18% Mx group. Higher hepatic lipid content was found in fish fed lower dietary carbohydrate levels. PS induced higher liver and white muscle hexokinase and pyruvate kinase activities compared to the lower values observed for Mx. Malic enzyme and glucose 6-phosphate dehydrogenase in liver and white muscle were lower in Mx group. The influence of dietary carbohydrates source was more noticeable than those induced by the carbohydrate level, when glycolysis and lipogenesis pathways were considered. Common dentex is able to use properly dietary carbohydrates, although optimal dietary inclusion levels are below 24%. The greater protein-sparing effect was promoted by the less complex carbohydrate (maltodextrin) and the best feed utilization indices were obtained at intermediate levels of inclusion (18%). Copyright © 2015 Elsevier Inc. All rights reserved.

Phylogenetic diversity of carbohydrate degrading culturable bacteria from Mandovi and Zuari estuaries, Goa, west coast of India

NASA Astrophysics Data System (ADS)

Khandeparker, Rakhee; Verma, Preeti; Meena, Ram M.; Deobagkar, Deepti D.

2011-12-01

Coastal and estuarine waters are highly productive and dynamic ecosystems. The complex carbohydrate composition of the ecosystem would lead to colonisation of microbial communities with abilities to produce an array of complex carbohydrate degrading enzymes. We have examined the abundance and phylogenetic diversity of culturable bacteria with abilities to produce complex carbohydrate degrading enzymes in the Mondovi and Zuari eustauri. It was interesting to note that 65% of isolated bacteria could produce complex carbohydrate degrading enzymes. A majority of these bacteria belonged to Bacillus genera followed by Vibrio, Marinobacter, Exiquinobacterium, Alteromonas, Enterobacter and Aeromonas. Most abundant bacterial genus to degrade hemicellulose and cellulose were Bacillus and Vibrio respectively. Most abundant bacterial genus to degrade hemicellulose and cellulose were Bacillus and Vibrio respectively. It was seen that 46% of Bacillus had ability to degrade both the substrate while only 14% of Vibrio had bifunctionality.

Molecular simulations of carbohydrates and protein-carbohydrate interactions: motivation, issues and prospects

PubMed Central

Fadda, Elisa; Woods, Robert J.

2014-01-01

The characterization of the 3D structure of oligosaccharides, their conjugates and analogs is particularly challenging for traditional experimental methods. Molecular simulation methods provide a basis for interpreting sparse experimental data and for independently predicting conformational and dynamic properties of glycans. Here, we summarize and analyze the issues associated with modeling carbohydrates, with a detailed discussion of four of the most recently developed carbohydrate force fields, reviewed in terms of applicability to natural glycans, carbohydrate–protein complexes and the emerging area of glycomimetic drugs. In addition, we discuss prospectives and new applications of carbohydrate modeling in drug discovery. PMID:20594934

Crystallization and preliminary crystallographic studies of a novel noncatalytic carbohydrate-binding module from the Ruminococcus flavefaciens cellulosome.

PubMed

Venditto, Immacolata; Goyal, Arun; Thompson, Andrew; Ferreira, Luis M A; Fontes, Carlos M G A; Najmudin, Shabir

2015-01-01

Microbial degradation of the plant cell wall is a fundamental biological process with considerable industrial importance. Hydrolysis of recalcitrant polysaccharides is orchestrated by a large repertoire of carbohydrate-active enzymes that display a modular architecture in which a catalytic domain is connected via linker sequences to one or more noncatalytic carbohydrate-binding modules (CBMs). CBMs direct the appended catalytic modules to their target substrates, thus potentiating catalysis. The genome of the most abundant ruminal cellulolytic bacterium, Ruminococcus flavefaciens strain FD-1, provides an opportunity to discover novel cellulosomal proteins involved in plant cell-wall deconstruction. It encodes a modular protein comprising a glycoside hydrolase family 9 catalytic module (GH9) linked to two unclassified tandemly repeated CBMs (termed CBM-Rf6A and CBM-Rf6B) and a C-terminal dockerin. The novel CBM-Rf6A from this protein has been crystallized and data were processed for the native and a selenomethionine derivative to 1.75 and 1.5 Å resolution, respectively. The crystals belonged to orthorhombic and cubic space groups, respectively. The structure was solved by a single-wavelength anomalous dispersion experiment using the CCP4 program suite and SHELXC/D/E.

Isolation of carbohydrate-metabolizing, extremely halophilic bacteria.

NASA Technical Reports Server (NTRS)

Tomlinson, G. A.; Hochstein, L. I.

1972-01-01

Four previously unrecognized strains of extremely halophilic bacteria that utilize carbohydrates have been isolated. Gas production proved an unreliable index of carbohydrate metabolism; therefore, carbohydrate utilization was measured by determining acid formation and sugar disappearance during growth. By these procedures, carbohydrate utilization was readily detected. The results suggest that carbohydrate dissimilation by extremely halophilic bacteria may be more common than previously thought and that the apparent rarity of carbohydrate-metabolizing halophiles may be an artifact of the isolation procedures used.

Lignin composition is more important than content for maize stem cell wall degradation.

PubMed

He, Yuan; Mouthier, Thibaut Mb; Kabel, Mirjam A; Dijkstra, Jan; Hendriks, Wouter H; Struik, Paul C; Cone, John W

2018-01-01

The relationship between the chemical and molecular properties - in particular the (acid detergent) lignin (ADL) content and composition expressed as the ratio between syringyl and guaiacyl compounds (S:G ratio) - of maize stems and in vitro gas production was studied in order to determine which is more important in the degradability of maize stem cell walls in the rumen of ruminants. Different internodes from two contrasting maize cultivars (Ambrosini and Aastar) were harvested during the growing season. The ADL content decreased with greater internode number within the stem, whereas the ADL content fluctuated during the season for both cultivars. The S:G ratio was lower in younger tissue (greater internode number or earlier harvest date) in both cultivars. For the gas produced between 3 and 20 h, representing the fermentation of cell walls in rumen fluid, a stronger correlation (R 2 = 0.80) was found with the S:G ratio than with the ADL content (R 2 = 0.68). The relationship between ADL content or S:G ratio and 72-h gas production, representing total organic matter degradation, was weaker than that with gas produced between 3 and 20 h. The S:G ratio plays a more dominant role than ADL content in maize stem cell wall degradation. © 2017 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. © 2017 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Optimization of wall thickness and lay-up for the shell-like composite structure loaded by non-uniform pressure field

NASA Astrophysics Data System (ADS)

Shevtsov, S.; Zhilyaev, I.; Oganesyan, P.; Axenov, V.

2017-01-01

The glass/carbon fiber composites are widely used in the design of various aircraft and rotorcraft components such as fairings and cowlings, which have predominantly a shell-like geometry and are made of quasi-isotropic laminates. The main requirements to such the composite parts are the specified mechanical stiffness to withstand the non-uniform air pressure at the different flight conditions and reduce a level of noise caused by the airflow-induced vibrations at the constrained weight of the part. The main objective of present study is the optimization of wall thickness and lay-up of composite shell-like cowling. The present approach assumes conversion of the CAD model of the cowling surface to finite element (FE) representation, then its wind tunnel testing simulation at the different orientation of airflow to find the most stressed mode of flight. Numerical solutions of the Reynolds averaged Navier-Stokes (RANS) equations supplemented by k-w turbulence model provide the spatial distributions of air pressure applied to the shell surface. At the formulation of optimization problem the global strain energy calculated within the optimized shell was assumed as the objective. A wall thickness of the shell had to change over its surface to minimize the objective at the constrained weight. We used a parameterization of the problem that assumes an initiation of auxiliary sphere with varied radius and coordinates of the center, which were the design variables. Curve that formed by the intersection of the shell with sphere defined boundary of area, which should be reinforced by local thickening the shell wall. To eliminate a local stress concentration this increment was defined as the smooth function defined on the shell surface. As a result of structural optimization we obtained the thickness of shell's wall distribution, which then was used to design the draping and lay-up of composite prepreg layers. The global strain energy in the optimized cowling was reduced in2

Recognition and Degradation of Plant Cell Wall Polysaccharides by Two Human Gut Symbionts

PubMed Central

Chiang, Herbert; Pudlo, Nicholas A.; Wu, Meng; McNulty, Nathan P.; Abbott, D. Wade; Henrissat, Bernard; Gilbert, Harry J.; Bolam, David N.; Gordon, Jeffrey I.

2011-01-01

Symbiotic bacteria inhabiting the human gut have evolved under intense pressure to utilize complex carbohydrates, primarily plant cell wall glycans in our diets. These polysaccharides are not digested by human enzymes, but are processed to absorbable short chain fatty acids by gut bacteria. The Bacteroidetes, one of two dominant bacterial phyla in the adult gut, possess broad glycan-degrading abilities. These species use a series of membrane protein complexes, termed Sus-like systems, for catabolism of many complex carbohydrates. However, the role of these systems in degrading the chemically diverse repertoire of plant cell wall glycans remains unknown. Here we show that two closely related human gut Bacteroides, B. thetaiotaomicron and B. ovatus, are capable of utilizing nearly all of the major plant and host glycans, including rhamnogalacturonan II, a highly complex polymer thought to be recalcitrant to microbial degradation. Transcriptional profiling and gene inactivation experiments revealed the identity and specificity of the polysaccharide utilization loci (PULs) that encode individual Sus-like systems that target various plant polysaccharides. Comparative genomic analysis indicated that B. ovatus possesses several unique PULs that enable degradation of hemicellulosic polysaccharides, a phenotype absent from B. thetaiotaomicron. In contrast, the B. thetaiotaomicron genome has been shaped by increased numbers of PULs involved in metabolism of host mucin O-glycans, a phenotype that is undetectable in B. ovatus. Binding studies of the purified sensor domains of PUL-associated hybrid two-component systems in conjunction with transcriptional analyses demonstrate that complex oligosaccharides provide the regulatory cues that induce PUL activation and that each PUL is highly specific for a defined cell wall polymer. These results provide a view of how these species have diverged into different carbohydrate niches by evolving genes that target unique suites of

Is carbohydrate needed to further stimulate muscle protein synthesis/hypertrophy following resistance exercise?

PubMed Central

2013-01-01

It is now well established that protein supplementation after resistance exercise promotes increased muscle protein synthesis, which ultimately results in greater net muscle accretion, relative to exercise alone or exercise with supplementary carbohydrate ingestion. However, it is not known whether combining carbohydrate with protein produces a greater anabolic response than protein alone. Recent recommendations have been made that the composition of the ideal supplement post-exercise would be a combination of a protein source with a high glycemic index carbohydrate. This is based on the hypothesis that insulin promotes protein synthesis, thus maximising insulin secretion will maximally potentiate this action. However, it is still controversial as to whether raising insulin level, within the physiological range, has any effect to further stimulate muscle protein synthesis. The present commentary will review the evidence underpinning the recommendation to consume carbohydrates in addition to a protein supplementation after resistance exercise for the specific purpose of increasing muscle mass. The paucity of data will be discussed, thus our conclusions are that further studies are necessary prior to any conclusions that enable evidence-based recommendations to be made. PMID:24066806

Effects of dietary carbohydrates sources on lipids compositions in abalone, Haliotis discus hannai Ino

NASA Astrophysics Data System (ADS)

Wang, Weifang; Mai, Kangsen; Zhang, Wenbing; Xu, Wei; Ai, Qinghui; Yao, Chunfeng; Li, Huitao

2009-09-01

A study was conducted to evaluate the effects of dietary carbohydrates on triglyceride, cholesterol and fatty acid concentrations in abalone, Haliotis discus hannai Ino. Six semi-purified diets with different carbohydrates (dextrin, heat-treated wheat starch, wheat starch, corn starch, tapioca starch and potato starch, respectively), all containing a carbohydrate level of 33.5%, were fed to abalone (initial shell length: 29.98 mm ± 0.09 mm; initial weight: 3.42 g ± 0.02 g) for 24 weeks in a recirculation system. The results indicate that serum triglyceride concentrations were significantly ( P < 0.05) higher in the abalone fed with dextrin, heat-treated wheat starch and wheat starch than those fed with corn starch, and serum cholesterol concentrations were significantly ( P < 0.05) higher in the abalone fed with dextrin, heat-treated wheat starch than those fed with corn starch. Fatty acid C20:4n-6 in the foot muscles were significantly ( P < 0.05) lower in the abalone fed with dextrin than those fed with wheat starch, corn starch, tapioca starch and potato starch. Fatty acid C20:4n-6 in hepatopancreas was significantly ( P < 0.05) lower in abalone fed with heat-treated wheat starch than those fed with corn starch, tapioca starch and potato starch. Fatty acid C22:6n-3 in the foot muscles were significantly ( P < 0.05) lower in the abalone fed with dextrin and heat-treated wheat starch than those fed with wheat starch and potato starch.

Effect of acarbose on postprandial blood glucose concentrations in healthy cats fed low and high carbohydrate diets.

PubMed

Singh, Ranee; Rand, Jacquie S; Coradini, Marcia; Morton, John M

2015-10-01

Feeding a low carbohydrate diet is recommended for diabetic cats; however, some cats may require diets containing moderate-to-high carbohydrate and may benefit from the use of therapeutic agents to improve glycemic control. The aim of the study was to determine the effect of the α-glucosidase inhibitor acarbose on postprandial plasma glucose concentration when combined with commercially available feline diets high and low in carbohydrate. Twelve healthy, adult, non-obese, neutered cats were enrolled. Plasma glucose concentrations were assessed over 24 h after feeding high and low carbohydrate diets, with and without acarbose, during single and multiple meal tests, in a crossover study. Commercially available feline diets were used, which were high and low in carbohydrate (providing 51% and 7% of metabolizable energy, respectively). In cats fed the high carbohydrate diet as a single meal, mean 24 h glucose concentrations were lower when acarbose was administered. Mean glucose concentrations were lower in the first 12 h when acarbose was given once daily, whereas no significant difference was observed in mean results from 12-24 h. Acarbose had little effect in cats eating multiple meals. Compared with consumption of the high carbohydrate diet with acarbose, lower mean 24 h and peak glucose concentrations were achieved by feeding the low carbohydrate diet alone. In healthy cats meal-fed diets of similar composition to the diets used in this study, acarbose has minimal effect when a low carbohydrate diet is fed but reduces postprandial glucose concentrations over 24 h when a high carbohydrate diet is fed. However, mean glucose concentrations over 24 h are still higher when a high carbohydrate diet with acarbose is fed relative to the low carbohydrate diet without acarbose. Future studies in diabetic cats are warranted to confirm these findings. © ISFM and AAFP 2014.

Method for conversion of carbohydrate polymers to value-added chemical products

DOEpatents

Zhang, Zongchao C [Norwood, NJ; Brown, Heather M [Kennewick, WA; Su, Yu [Richland, WA

2012-02-07

Methods are described for conversion of carbohydrate polymers in ionic liquids, including cellulose, that yield value-added chemicals including, e.g., glucose and 5-hydroxylmethylfurfural (HMF) at temperatures below 120.degree. C. Catalyst compositions that include various mixed metal halides are described that are selective for specified products with yields, e.g., of up to about 56% in a single step process.

Verification of protein sparing by feeding carbohydrate to common carp Cyprinus carpio

NASA Astrophysics Data System (ADS)

Cheng, Zhenyan; Li, Jinghui; Zhang, Baolong; Fang, Zhenzhen; Sun, Jinhui; Bai, Dongqing; Sun, Jinsheng; Qiao, Xiuting

2017-03-01

A 9-week feeding trial in floating freshwater cages (1.0 m×1.0 m×2.0 m) was conducted to study the effects of different dietary levels of protein and starch on growth, body composition, and gene expression of enzymes in common carp, Cyprinus carpio (mean body weight, 36.12±1.18 g) to evaluate the protein-sparing effect of dietary carbohydrate. Four diets were formulated with corn starch as the carbohydrate source to obtain corn starch levels of 6.5%, 13%, 19.5%, or 26% and protein levels of 30.5%, 28.2%, 26.4%, and 24.2%. The results showed no differences in growth performance of fish fed the diets with different protein and corn starch levels, but body composition and glucose metabolic enzyme activity of carp were significantly affected by the different diets ( P< 0.05). Weight gain, specific growth rate, and the feed conversion ratio were not different in fish fed the different dietary treatments. Protein efficiency ratio increased significantly as corn starch level increased ( P< 0.05). Whole-body crude lipid composition increased with increasing dietary corn starch level ( P< 0.05). Glucokinase (GK), hexokinase, and pyruvate kinase (PK) activities increased significantly with increasing dietary corn starch level ( P< 0.05), whereas glucose-6-phosphate (G6Pase) activity decreased with increasing dietary corn starch level ( P< 0.05). GK gene expression was significantly higher in fish fed the high-corn starch diet than those fed the low-corn starch diet ( P< 0.05). G6pase gene expression tended to decrease with increasing starch level ( P> 0.05). In summary, the results indicate a protein-sparing effect by substituting carbohydrate in the diet of common carp.

Grass cell walls: A story of cross-linking

USDA-ARS?s Scientific Manuscript database

Cell wall matrices are complex composites mainly of polysaccharides, phenolics (monomers and polymers), and protein. We are beginning to understand the synthesis of these major wall components individually, but still have a poor understanding of how the cell wall components are assembled into comple...

Carbohydrate Strategies for Injury Prevention

PubMed Central

Schlabach, Gretchen

1994-01-01

Prevention of injury involves identifying risk factors that would predispose one to injury and developing strategies to attenuate or eliminate their presence. Because muscle glycogen depletion is associated with fatigue and injury, it should be treated as a possible risk factor. Muscle glycogen stores are derived almost entirely from carbohydrate intake. Because there is a limited capacity to store muscle glycogen, and because muscle glycogen is the predominant fuel in exercise of moderate to severe intensity, the nutritional focus should be on carbohydrate consumption. Easy-to-follow nutritional strategies should be employed that will maximize muscle glycogen stores and delay the onset of fatigue. Individuals involved in activities lasting less than 60 minutes need to consume an adequate amount of carbohydrate daily and a pre-event meal before the start of the activity. However, individuals participating in activities longer than 60 minutes or participating in activities requiring repeated bouts of high intensity exercise need to: 1) consume an adequate amount of carbohydrate daily, 2) practice carbohydrate loading, 3) consume the pre-event meal, and 4) ingest carbohydrates immediately before, during, and after the activity. PMID:16558287

Fabrication of Carbohydrate Microarrays by Boronate Formation.

PubMed

Adak, Avijit K; Lin, Ting-Wei; Li, Ben-Yuan; Lin, Chun-Cheng

2017-01-01

The interactions between soluble carbohydrates and/or surface displayed glycans and protein receptors are essential to many biological processes and cellular recognition events. Carbohydrate microarrays provide opportunities for high-throughput quantitative analysis of carbohydrate-protein interactions. Over the past decade, various techniques have been implemented for immobilizing glycans on solid surfaces in a microarray format. Herein, we describe a detailed protocol for fabricating carbohydrate microarrays that capitalizes on the intrinsic reactivity of boronic acid toward carbohydrates to form stable boronate diesters. A large variety of unprotected carbohydrates ranging in structure from simple disaccharides and trisaccharides to considerably more complex human milk and blood group (oligo)saccharides have been covalently immobilized in a single step on glass slides, which were derivatized with high-affinity boronic acid ligands. The immobilized ligands in these microarrays maintain the receptor-binding activities including those of lectins and antibodies according to the structures of their pendant carbohydrates for rapid analysis of a number of carbohydrate-recognition events within 30 h. This method facilitates the direct construction of otherwise difficult to obtain carbohydrate microarrays from underivatized glycans.

The impact of carbohydrate and protein level and sources on swine manure foaming properties

USDA-ARS?s Scientific Manuscript database

This study explored the impact of swine diet on the composition, methane production potential, and foaming properties of manure. Samples of swine manure were collected from controlled feeding trials with diets varying in protein and carbohydrate levels and sources. Protein sources consisted of corn ...

Carbohydrate maldigestion induces necrotizing enterocolitis in preterm pigs

PubMed Central

Thymann, Thomas; Møller, Hanne K.; Stoll, Barbara; Støy, Ann Cathrine F.; Buddington, Randal K.; Bering, Stine B.; Jensen, Bent B.; Olutoye, Oluyinka O.; Siggers, Richard H.; Mølbak, Lars; Sangild, Per T.

2009-01-01

Necrotizing enterocolitis (NEC) remains the most severe gastrointestinal disorder in preterm infants. It is associated with the initiation of enteral nutrition and may be related to immature carbohydrate digestive capacity. We tested the hypothesis that a formula containing maltodextrin vs. a formula containing lactose as the principal source of carbohydrate would predispose preterm pigs to a higher NEC incidence. Cesarean-derived preterm pigs were given total parenteral nutrition for 48 h followed by total enteral nutrition with a lactose-based (n = 11) or maltodextrin-based (n = 11) formula for 36 h. A higher incidence (91% vs. 27%) and severity (score of 3.3 vs. 1.8) of NEC were observed in the maltodextrin than in the lactose group. This higher incidence of NEC in the maltodextrin group was associated with significantly lower activities of lactase, maltase, and aminopeptidase; reduced villus height; transiently reduced in vivo aldohexose uptake; and reduced ex vivo aldohexose uptake capacity in the middle region of the small intestine. Bacterial diversity was low for both diets, but alterations in bacterial composition and luminal concentrations of short-chain fatty acids were observed in the maltodextrin group. In a second study, we quantified net portal absorption of aldohexoses (glucose and galactose) during acute jejunal infusion of a maltodextrin- or a lactose-based formula (n = 8) into preterm pigs. We found lower net portal aldohexose absorption (4% vs. 42%) and greater intestinal recovery of undigested carbohydrate (68% vs. 27%) in pigs acutely perfused with the maltodextrin-based formula than those perfused with the lactose-based formula. The higher digestibility of the lactose than the maltodextrin in the formulas can be attributed to a 5- to 20-fold higher hydrolytic activity of tissue-specific lactase than maltases. We conclude that carbohydrate maldigestion is sufficient to increase the incidence and severity of NEC in preterm pigs. PMID:19808655

Cell Wall Composition, Biosynthesis and Remodeling during Pollen Tube Growth

PubMed Central

Mollet, Jean-Claude; Leroux, Christelle; Dardelle, Flavien; Lehner, Arnaud

2013-01-01

The pollen tube is a fast tip-growing cell carrying the two sperm cells to the ovule allowing the double fertilization process and seed setting. To succeed in this process, the spatial and temporal controls of pollen tube growth within the female organ are critical. It requires a massive cell wall deposition to promote fast pollen tube elongation and a tight control of the cell wall remodeling to modify the mechanical properties. In addition, during its journey, the pollen tube interacts with the pistil, which plays key roles in pollen tube nutrition, guidance and in the rejection of the self-incompatible pollen. This review focuses on our current knowledge in the biochemistry and localization of the main cell wall polymers including pectin, hemicellulose, cellulose and callose from several pollen tube species. Moreover, based on transcriptomic data and functional genomic studies, the possible enzymes involved in the cell wall remodeling during pollen tube growth and their impact on the cell wall mechanics are also described. Finally, mutant analyses have permitted to gain insight in the function of several genes involved in the pollen tube cell wall biosynthesis and their roles in pollen tube growth are further discussed. PMID:27137369

The role of the cell wall in fungal pathogenesis

PubMed Central

Arana, David M.; Prieto, Daniel; Román, Elvira; Nombela, César; Alonso‐Monge, Rebeca; Pla, Jesús

2009-01-01

Summary Fungal infections are a serious health problem. In recent years, basic research is focusing on the identification of fungal virulence factors as promising targets for the development of novel antifungals. The wall, as the most external cellular component, plays a crucial role in the interaction with host cells mediating processes such as adhesion or phagocytosis that are essential during infection. Specific components of the cell wall (called PAMPs) interact with specific receptors in the immune cell (called PRRs), triggering responses whose molecular mechanisms are being elucidated. We review here the main structural carbohydrate components of the fungal wall (glucan, mannan and chitin), how their biogenesis takes place in fungi and the specific receptors that they interact with. Different model fungal pathogens are chosen to illustrate the functional consequences of this interaction. Finally, the identification of the key components will have important consequences in the future and will allow better approaches to treat fungal infections. PMID:21261926

Synthesis of single-walled carbon nanotubes and graphene composite in arc for ultracapacitors

NASA Astrophysics Data System (ADS)

Li, Jian; Cheng, Xiaoqian; Shashurin, Alexey; Keidar, Michael

2012-10-01

Arc discharge supported by the erosion of graphite anode is considered as one of the most practical and efficient methods to synthesize various carbon nanostructures such as single-walled carbon nanotubes (SWCNT) and graphene with minimal defects and large yield due to the relatively high synthesis temperature and eco-friendly growth mechanism. By introducing a non-uniform magnetic field during synthesis process, large-scale graphene and high-purity SWCNT can be obtained in one step. In addition, the yield of graphene can be controlled by external parameters, such as the type and pressure of buffer gas, the temperature of substrate, and so on. Possessing the properties of highly accessible surface area and good electrical conductivity, the composite of graphene and SWCNT are promising nanomaterials for the electrodes of ultracapacitor, which can store electric energy with high level of capacitance. In this work, we fabricated electrodes of ultracapacitor based on nanostructures composite by wire-wound rod coating method, characterized them by SEM, EDX and Raman spectroscopy, and tested the performance by a potentiostat/galvanostat.

Comparative glycan profiling of Ceratopteris richardii 'C-Fern' gametophytes and sporophytes links cell-wall composition to functional specialization.

PubMed

Eeckhout, Sharon; Leroux, Olivier; Willats, William G T; Popper, Zoë A; Viane, Ronald L L

2014-10-01

Innovations in vegetative and reproductive characters were key factors in the evolutionary history of land plants and most of these transformations, including dramatic changes in life cycle structure and strategy, necessarily involved cell-wall modifications. To provide more insight into the role of cell walls in effecting changes in plant structure and function, and in particular their role in the generation of vascularization, an antibody-based approach was implemented to compare the presence and distribution of cell-wall glycan epitopes between (free-living) gametophytes and sporophytes of Ceratopteris richardii 'C-Fern', a widely used model system for ferns. Microarrays of sequential diamino-cyclohexane-tetraacetic acid (CDTA) and NaOH extractions of gametophytes, spores and different organs of 'C-Fern' sporophytes were probed with glycan-directed monoclonal antibodies. The same probes were employed to investigate the tissue- and cell-specific distribution of glycan epitopes. While monoclonal antibodies against pectic homogalacturonan, mannan and xyloglucan widely labelled gametophytic and sporophytic tissues, xylans were only detected in secondary cell walls of the sporophyte. The LM5 pectic galactan epitope was restricted to sporophytic phloem tissue. Rhizoids and root hairs showed similarities in arabinogalactan protein (AGP) and xyloglucan epitope distribution patterns. The differences and similarities in glycan cell-wall composition between 'C-Fern' gametophytes and sporophytes indicate that the molecular design of cell walls reflects functional specialization rather than genetic origin. Glycan epitopes that were not detected in gametophytes were associated with cell walls of specialized tissues in the sporophyte. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

The effect of ultrasonic processing of multi-wall carbon nanotubes on properties of elastomeric compositions on the basis of synthetic isoprene rubber

NASA Astrophysics Data System (ADS)

Mitryaeva, N. S.; Myshlyavtsev, A. V.; Akimenko, S. S.

2017-08-01

The paper studies the effect of ultrasonic processing on the vulcanizing, physical, mechanical and electrophysical properties of elastomeric compositions based on synthetic isoprene rubber. Microscopic studies of multi-wall carbon nanotubes samples before and after ultrasonic processing are carried out. Due to the research, the applied ultrasonic processing method provides splitting of bundles formed from multi-wall carbon nanotubes. This results in elastomeric material with increased strength and high electrical conductivity with a low concentration of nanofiller.

Analysis of thin-walled cylindrical composite shell structures subject to axial and bending loads: Concept development, analytical modeling and experimental verification

NASA Astrophysics Data System (ADS)

Mahadev, Sthanu

Continued research and development efforts devoted in recent years have generated novel avenues towards the advancement of efficient and effective, slender laminated fiber-reinforced composite members. Numerous studies have focused on the modeling and response characterization of composite structures with particular relevance to thin-walled cylindrical composite shells. This class of shell configurations is being actively explored to fully determine their mechanical efficacy as primary aerospace structural members. The proposed research is targeted towards formulating a composite shell theory based prognosis methodology that entails an elaborate analysis and investigation of thin-walled cylindrical shell type laminated composite configurations that are highly desirable in increasing number of mechanical and aerospace applications. The prime motivation to adopt this theory arises from its superior ability to generate simple yet viable closed-form analytical solution procedure to numerous geometrically intense, inherent curvature possessing composite structures. This analytical evaluative routine offers to acquire a first-hand insight on the primary mechanical characteristics that essentially govern the behavior of slender composite shells under typical static loading conditions. Current work exposes the robustness of this mathematical framework via demonstrating its potential towards the prediction of structural properties such as axial stiffness and bending stiffness respectively. Longitudinal ply-stress computations are investigated upon deriving the global stiffness matrix model for composite cylindrical tubes with circular cross-sections. Additionally, this work employs a finite element based numerical technique to substantiate the analytical results reported for cylindrically shaped circular composite tubes. Furthermore, this concept development is extended to the study of thin-walled, open cross-sectioned, curved laminated shells that are geometrically

Transparent and flexible electrodes and supercapacitors using polyaniline/single-walled carbon nanotube composite thin films

NASA Astrophysics Data System (ADS)

Ge, Jun; Cheng, Guanghui; Chen, Liwei

2011-08-01

Large-scale transparent and flexible electronic devices have been pursued for potential applications such as those in touch sensors and display technologies. These applications require that the power source of these devices must also comply with transparent and flexible features. Here we present transparent and flexible supercapacitors assembled from polyaniline (PANI)/single-walled carbon nanotube (SWNT) composite thin film electrodes. The ultrathin, optically homogeneous and transparent, electrically conducting films of the PANI/SWNT composite show a large specific capacitance due to combined double-layer capacitance and pseudo-capacitance mechanisms. A supercapacitor assembled using electrodes with a SWNT density of 10.0 µg cm-2 and 59 wt% PANI gives a specific capacitance of 55.0 F g-1 at a current density of 2.6 A g-1, showing its possibility for transparent and flexible energy storage.

Activating Intrinsic Carbohydrate-Active Enzymes of the Smut Fungus Ustilago maydis for the Degradation of Plant Cell Wall Components

PubMed Central

Geiser, Elena; Reindl, Michèle; Blank, Lars M.; Feldbrügge, Michael

2016-01-01

ABSTRACT The microbial conversion of plant biomass to valuable products in a consolidated bioprocess could greatly increase the ecologic and economic impact of a biorefinery. Current strategies for hydrolyzing plant material mostly rely on the external application of carbohydrate-active enzymes (CAZymes). Alternatively, production organisms can be engineered to secrete CAZymes to reduce the reliance on externally added enzymes. Plant-pathogenic fungi have a vast repertoire of hydrolytic enzymes to sustain their lifestyle, but expression of the corresponding genes is usually highly regulated and restricted to the pathogenic phase. Here, we present a new strategy in using the biotrophic smut fungus Ustilago maydis for the degradation of plant cell wall components by activating its intrinsic enzyme potential during axenic growth. This fungal model organism is fully equipped with hydrolytic enzymes, and moreover, it naturally produces value-added substances, such as organic acids and biosurfactants. To achieve the deregulated expression of hydrolytic enzymes during the industrially relevant yeast-like growth in axenic culture, the native promoters of the respective genes were replaced by constitutively active synthetic promoters. This led to an enhanced conversion of xylan, cellobiose, and carboxymethyl cellulose to fermentable sugars. Moreover, a combination of strains with activated endoglucanase and β-glucanase increased the release of glucose from carboxymethyl cellulose and regenerated amorphous cellulose, suggesting that mixed cultivations could be a means for degrading more complex substrates in the future. In summary, this proof of principle demonstrates the potential applicability of activating the expression of native CAZymes from phytopathogens in a biocatalytic process. IMPORTANCE This study describes basic experiments that aim at the degradation of plant cell wall components by the smut fungus Ustilago maydis. As a plant pathogen, this fungus contains a

Plant and algal cell walls: diversity and functionality

PubMed Central

Popper, Zoë A.; Ralet, Marie-Christine; Domozych, David S.

2014-01-01

Background Although plants and many algae (e.g. the Phaeophyceae, brown, and Rhodophyceae, red) are only very distantly related they are united in their possession of carbohydrate-rich cell walls, which are of integral importance being involved in many physiological processes. Furthermore, wall components have applications within food, fuel, pharmaceuticals, fibres (e.g. for textiles and paper) and building materials and have long been an active topic of research. As shown in the 27 papers in this Special Issue, as the major deposit of photosynthetically fixed carbon, and therefore energy investment, cell walls are of undisputed importance to the organisms that possess them, the photosynthetic eukaryotes (plants and algae). The complexities of cell wall components along with their interactions with the biotic and abiotic environment are becoming increasingly revealed. Scope The importance of plant and algal cell walls and their individual components to the function and survival of the organism, and for a number of industrial applications, are illustrated by the breadth of topics covered in this issue, which includes papers concentrating on various plants and algae, developmental stages, organs, cell wall components, and techniques. Although we acknowledge that there are many alternative ways in which the papers could be categorized (and many would fit within several topics), we have organized them as follows: (1) cell wall biosynthesis and remodelling, (2) cell wall diversity, and (3) application of new technologies to cell walls. Finally, we will consider future directions within plant cell wall research. Expansion of the industrial uses of cell walls and potentially novel uses of cell wall components are both avenues likely to direct future research activities. Fundamentally, it is the continued progression from characterization (structure, metabolism, properties and localization) of individual cell wall components through to defining their roles in almost every

Plant and algal cell walls: diversity and functionality.

PubMed

Popper, Zoë A; Ralet, Marie-Christine; Domozych, David S

2014-10-01

Although plants and many algae (e.g. the Phaeophyceae, brown, and Rhodophyceae, red) are only very distantly related they are united in their possession of carbohydrate-rich cell walls, which are of integral importance being involved in many physiological processes. Furthermore,wall components have applications within food, fuel, pharmaceuticals, fibres (e.g. for textiles and paper) and building materials and have long been an active topic of research. As shown in the 27 papers in this Special Issue, as the major deposit of photosynthetically fixed carbon, and therefore energy investment, cell walls are of undisputed importance to the organisms that possess them, the photosynthetic eukaryotes ( plants and algae). The complexities of cell wall components along with their interactions with the biotic and abiotic environment are becoming increasingly revealed. The importance of plant and algal cell walls and their individual components to the function and survival of the organism, and for a number of industrial applications, are illustrated by the breadth of topics covered in this issue, which includes papers concentrating on various plants and algae, developmental stages, organs, cell wall components, and techniques. Although we acknowledge that there are many alternative ways in which the papers could be categorized (and many would fit within several topics), we have organized them as follows: (1) cell wall biosynthesis and remodelling, (2) cell wall diversity, and (3) application of new technologies to cell walls. Finally, we will consider future directions within plant cell wall research. Expansion of the industrial uses of cell walls and potentially novel uses of cell wall components are both avenues likely to direct future research activities. Fundamentally, it is the continued progression from characterization (structure, metabolism, properties and localization) of individual cell wall components through to defining their roles in almost every aspect of plant

The β‐1,3‐glucanosyltransferases (Gels) affect the structure of the rice blast fungal cell wall during appressorium‐mediated plant infection

PubMed Central

Samalova, Marketa; Mélida, Hugo; Vilaplana, Francisco; Bulone, Vincent; Soanes, Darren M.; Talbot, Nicholas J.

2016-01-01

Abstract The fungal wall is pivotal for cell shape and function, and in interfacial protection during host infection and environmental challenge. Here, we provide the first description of the carbohydrate composition and structure of the cell wall of the rice blast fungus Magnaporthe oryzae. We focus on the family of glucan elongation proteins (Gels) and characterize five putative β‐1,3‐glucan glucanosyltransferases that each carry the Glycoside Hydrolase 72 signature. We generated targeted deletion mutants of all Gel isoforms, that is, the GH72+, which carry a putative carbohydrate‐binding module, and the GH72− Gels, without this motif. We reveal that M. oryzae GH72 + GELs are expressed in spores and during both infective and vegetative growth, but each individual Gel enzymes are dispensable for pathogenicity. Further, we demonstrated that a Δgel1Δgel3Δgel4 null mutant has a modified cell wall in which 1,3‐glucans have a higher degree of polymerization and are less branched than the wild‐type strain. The mutant showed significant differences in global patterns of gene expression, a hyper‐branching phenotype and no sporulation, and thus was unable to cause rice blast lesions (except via wounded tissues). We conclude that Gel proteins play significant roles in structural modification of the fungal cell wall during appressorium‐mediated plant infection. PMID:27568483

Predicting water-soluble carbohydrates and ethanol-soluble carbohydrates in cool-season grasses with near-infrared reflectance spectroscopy

USDA-ARS?s Scientific Manuscript database

Grazing animals may require a high or low total nonstructural carbohydrate diet for optimal health and production. Understanding how nonstructural carbohydrates fluctuate in Kentucky pastures and being able to quantify and monitor nonstructural carbohydrates in a timely manner will greatly aid in m...

Seasonal organic matter dynamics in the Great Barrier Reef lagoon: Contribution of carbohydrates and proteins

NASA Astrophysics Data System (ADS)

Lønborg, Christian; Doyle, Jason; Furnas, Miles; Menendez, Patricia; Benthuysen, Jessica A.; Carreira, Cátia

2017-04-01

Organic matter (OM) plays a fundamental role in sustaining the high productivity of coral reef ecosystems. Carbohydrates and proteins constitute two of the major chemical classes identified in the OM pool and are used as indicators of bioavailability due to their fast turn-over. We conducted three cruises across the southern shelf of the Great Barrier Reef (GBR) during the early dry, late dry and wet seasons in 2009-2010 to 1) assess the relative bioavailability of particulate (POM) and dissolved (DOM) organic matter, 2) track the temporal and spatial variability in the carbohydrate and protein contribution to the OM pool, and 3) assess factors influencing protein and carbohydrate fractions of the OM pool. Generally, higher concentrations of particulate carbohydrates were found during the wet season, while similar concentrations of particulate protein were found during the three seasons. Both the dissolved carbohydrates and proteins had highest levels during the early dry season and lowest during the wet season, suggesting seasonal variations in the chemical composition of the DOM pool. Spatially, carbohydrates showed higher concentrations at the inshore stations, while no clear spatial pattern was found for the protein concentrations. On average carbohydrates and proteins accounted for a similar fraction (13±5 and 12±6% respectively) of POM, while carbohydrates accounted for a smaller fraction of the DOM than the proteins (6±3 and 13±10%). This suggests that the POM bioavailability was similar between seasons, while the DOM bioavailability varied seasonally with highest levels during the early dry season. This demonstrates that carbohydrates and proteins in the GBR have temporal and spatial variations. Our statistical analysis showed that 1) both carbohydrates and proteins were related with the POM and DOM C:N:P stoichiometry, demonstrating that both bulk estimates (stoichiometry) and specific compounds (CHO and Prot) provide useful measures of OM

Comparative glycan profiling of Ceratopteris richardii ‘C-Fern’ gametophytes and sporophytes links cell-wall composition to functional specialization

PubMed Central

Eeckhout, Sharon; Leroux, Olivier; Willats, William G. T.; Popper, Zoë A.; Viane, Ronald L. L.

2014-01-01

Background and Aims Innovations in vegetative and reproductive characters were key factors in the evolutionary history of land plants and most of these transformations, including dramatic changes in life cycle structure and strategy, necessarily involved cell-wall modifications. To provide more insight into the role of cell walls in effecting changes in plant structure and function, and in particular their role in the generation of vascularization, an antibody-based approach was implemented to compare the presence and distribution of cell-wall glycan epitopes between (free-living) gametophytes and sporophytes of Ceratopteris richardii ‘C-Fern’, a widely used model system for ferns. Methods Microarrays of sequential diamino-cyclohexane-tetraacetic acid (CDTA) and NaOH extractions of gametophytes, spores and different organs of ‘C-Fern’ sporophytes were probed with glycan-directed monoclonal antibodies. The same probes were employed to investigate the tissue- and cell-specific distribution of glycan epitopes. Key Results While monoclonal antibodies against pectic homogalacturonan, mannan and xyloglucan widely labelled gametophytic and sporophytic tissues, xylans were only detected in secondary cell walls of the sporophyte. The LM5 pectic galactan epitope was restricted to sporophytic phloem tissue. Rhizoids and root hairs showed similarities in arabinogalactan protein (AGP) and xyloglucan epitope distribution patterns. Conclusions The differences and similarities in glycan cell-wall composition between ‘C-Fern’ gametophytes and sporophytes indicate that the molecular design of cell walls reflects functional specialization rather than genetic origin. Glycan epitopes that were not detected in gametophytes were associated with cell walls of specialized tissues in the sporophyte. PMID:24699895

Chemical and enzymatic fractionation of cell walls from Fucales: insights into the structure of the extracellular matrix of brown algae.

PubMed

Deniaud-Bouët, Estelle; Kervarec, Nelly; Michel, Gurvan; Tonon, Thierry; Kloareg, Bernard; Hervé, Cécile

2014-10-01

Brown algae are photosynthetic multicellular marine organisms evolutionarily distant from land plants, with a distinctive cell wall. They feature carbohydrates shared with plants (cellulose), animals (fucose-containing sulfated polysaccharides, FCSPs) or bacteria (alginates). How these components are organized into a three-dimensional extracellular matrix (ECM) still remains unclear. Recent molecular analysis of the corresponding biosynthetic routes points toward a complex evolutionary history that shaped the ECM structure in brown algae. Exhaustive sequential extractions and composition analyses of cell wall material from various brown algae of the order Fucales were performed. Dedicated enzymatic degradations were used to release and identify cell wall partners. This approach was complemented by systematic chromatographic analysis to study polymer interlinks further. An additional structural assessment of the sulfated fucan extracted from Himanthalia elongata was made. The data indicate that FCSPs are tightly associated with proteins and cellulose within the walls. Alginates are associated with most phenolic compounds. The sulfated fucans from H. elongata were shown to have a regular α-(1→3) backbone structure, while an alternating α-(1→3), (1→4) structure has been described in some brown algae from the order Fucales. The data provide a global snapshot of the cell wall architecture in brown algae, and contribute to the understanding of the structure-function relationships of the main cell wall components. Enzymatic cross-linking of alginates by phenols may regulate the strengthening of the wall, and sulfated polysaccharides may play a key role in the adaptation to osmotic stress. The emergence and evolution of ECM components is further discussed in relation to the evolution of multicellularity in brown algae. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please

Protein v. carbohydrate intake differentially affects liking- and wanting-related brain signalling.

PubMed

Born, Jurriaan M; Martens, Mieke J I; Lemmens, Sofie G T; Goebel, Rainer; Westerterp-Plantenga, Margriet S

2013-01-28

Extreme macronutrient intakes possibly lead to different brain signalling. The aim of the present study was to determine the effects of ingesting high-protein v. high-carbohydrate food on liking and wanting task-related brain signalling (TRS) and subsequent macronutrient intake. A total of thirty female subjects (21.6 (SD 2.2) years, BMI 25.0 (SD 3.7) kg/m²) completed four functional MRI scans: two fasted and two satiated on two different days. During the scans, subjects rated all food items for liking and wanting, thereby choosing the subsequent meal. The results show that high-protein (PROT) v. high-carbohydrate (CARB) conditions were generated using protein or carbohydrate drinks at the first meal. Energy intake and hunger were recorded. PROT (protein: 53.7 (SD 2.1) percentage of energy (En%); carbohydrate: 6.4 (SD 1.3) En%) and CARB conditions (protein: 11.8 (SD 0.6) En%; carbohydrate: 70.0 (SD 2.4) En%) were achieved during the first meal, while the second meals were not different between the conditions. Hunger, energy intake, and behavioural liking and wanting ratings were decreased after the first meal (P< 0.001). Comparing the first with the second meal, the macronutrient content changed: carbohydrate -26.9 En% in the CARB condition, protein -37.8 En% in the PROT condition. After the first meal in the CARB condition, wanting TRS was increased in the hypothalamus. After the first meal in the PROT condition, liking TRS was decreased in the putamen (P< 0.05). The change in energy intake from the first to the second meal was inversely related to the change in liking TRS in the striatum and hypothalamus in the CARB condition and positively related in the PROT condition (P< 0.05). In conclusion, wanting and liking TRS were affected differentially with a change in carbohydrate or protein intake, underscoring subsequent energy intake and shift in macronutrient composition.

From 'pleasure to chemistry': the experience of carbohydrate counting with and without carbohydrate restriction for people with Type 1 diabetes.

PubMed

Cresswell, Pip; Krebs, Jeremy; Gilmour, Jean; Hanna, Aoife; Parry-Strong, Amber

2015-12-01

Matching carbohydrate intake with insulin dosage is recommended management for people with Type 1 diabetes. However, international interest in restricted carbohydrate diets is growing. General practitioners and practice nurses need to know how to advise people with Type 1 diabetes regarding low-carbohydrate diets. This study aimed to explore the carbohydrate counting experiences of people with Type 1 diabetes in a trial with and without a diet restricted to 75 g of carbohydrate per day. Eight participants were interviewed by focus group or interview 12 weeks after a carbohydrate counting course with individual dietary choice or the same course with information on restricted carbohydrate eating and a daily maximum intake of 75 g of carbohydrate. Data were analysed using a qualitative thematic analysis approach. Themes included the need for insulin management skills, impact of the dietary experience, and need for dietary knowledge. The restricted-carbohydrate group encountered mealtime insulin resistance and difficulty managing insulin dosages when transitioning on and off the low-carbohydrate diet. The diet impacted on mood, feelings of satiety and it was reported that food changed from being 'a pleasure to chemistry'. Both groups described feeling empowered to manage their diabetes as a result of the carbohydrate counting course. Participants reported increased knowledge and challenging insulin management. The restricted-carbohydrate group reported mealtime insulin resistance and a strong dietary impact. Extra health professional support may be required, especially at dietary transition periods. More research is warranted into the reported mealtime insulin resistance.

Discovery and design of carbohydrate-based therapeutics.

PubMed

Cipolla, Laura; Araújo, Ana C; Bini, Davide; Gabrielli, Luca; Russo, Laura; Shaikh, Nasrin

2010-08-01

Till now, the importance of carbohydrates has been underscored, if compared with the two other major classes of biopolymers such as oligonucleotides and proteins. Recent advances in glycobiology and glycochemistry have imparted a strong interest in the study of this enormous family of biomolecules. Carbohydrates have been shown to be implicated in recognition processes, such as cell-cell adhesion, cell-extracellular matrix adhesion and cell-intruder recognition phenomena. In addition, carbohydrates are recognized as differentiation markers and as antigenic determinants. Due to their relevant biological role, carbohydrates are promising candidates for drug design and disease treatment. However, the growing number of human disorders known as congenital disorders of glycosylation that are being identified as resulting from abnormalities in glycan structures and protein glycosylation strongly indicates that a fast development of glycobiology, glycochemistry and glycomedicine is highly desirable. The topics give an overview of different approaches that have been used to date for the design of carbohydrate-based therapeutics; this includes the use of native synthetic carbohydrates, the use of carbohydrate mimics designed on the basis of their native counterpart, the use of carbohydrates as scaffolds and finally the design of glyco-fused therapeutics, one of the most recent approaches. The review covers mainly literature that has appeared since 2000, except for a few papers cited for historical reasons. The reader will gain an overview of the current strategies applied to the design of carbohydrate-based therapeutics; in particular, the advantages/disadvantages of different approaches are highlighted. The topic is presented in a general, basic manner and will hopefully be a useful resource for all readers who are not familiar with it. In addition, in order to stress the potentialities of carbohydrates, several examples of carbohydrate-based marketed therapeutics are given

Carbohydrates digestion and metabolism in the spiny lobster (Panulirus argus): biochemical indication for limited carbohydrate utilization.

PubMed

Rodríguez-Viera, Leandro; Perera, Erick; Montero-Alejo, Vivian; Perdomo-Morales, Rolando; García-Galano, Tsai; Martínez-Rodríguez, Gonzalo; Mancera, Juan M

2017-01-01

As other spiny lobsters, Panulirus argus is supposed to use preferentially proteins and lipids in energy metabolism, while carbohydrates are well digested but poorly utilized. The aim of this study was to evaluate the effect of dietary carbohydrate level on digestion and metabolism in the spiny lobster P. argus . We used complementary methodologies such as post-feeding flux of nutrients and metabolites, as well as measurements of α-amylase expression and activity in the digestive tract. Lobsters readily digested and absorbed carbohydrates with a time-course that is dependent on their content in diet. Lobster showed higher levels of free glucose and stored glycogen in different tissues as the inclusion of wheat flour increased. Modifications in intermediary metabolism revealed a decrease in amino acids catabolism coupled with a higher use of free glucose as carbohydrates rise up to 20%. However, this effect seems to be limited by the metabolic capacity of lobsters to use more than 20% of carbohydrates in diets. Lobsters were not able to tightly regulate α-amylase expression according to dietary carbohydrate level but exhibited a marked difference in secretion of this enzyme into the gut. Results are discussed to highlight the limitations to increasing carbohydrate utilization by lobsters. Further growout trials are needed to link the presented metabolic profiles with phenotypic outcomes.

Carbohydrates digestion and metabolism in the spiny lobster (Panulirus argus): biochemical indication for limited carbohydrate utilization

PubMed Central

Montero-Alejo, Vivian; Perdomo-Morales, Rolando; García-Galano, Tsai; Martínez-Rodríguez, Gonzalo; Mancera, Juan M.

2017-01-01

As other spiny lobsters, Panulirus argus is supposed to use preferentially proteins and lipids in energy metabolism, while carbohydrates are well digested but poorly utilized. The aim of this study was to evaluate the effect of dietary carbohydrate level on digestion and metabolism in the spiny lobster P. argus. We used complementary methodologies such as post-feeding flux of nutrients and metabolites, as well as measurements of α-amylase expression and activity in the digestive tract. Lobsters readily digested and absorbed carbohydrates with a time-course that is dependent on their content in diet. Lobster showed higher levels of free glucose and stored glycogen in different tissues as the inclusion of wheat flour increased. Modifications in intermediary metabolism revealed a decrease in amino acids catabolism coupled with a higher use of free glucose as carbohydrates rise up to 20%. However, this effect seems to be limited by the metabolic capacity of lobsters to use more than 20% of carbohydrates in diets. Lobsters were not able to tightly regulate α-amylase expression according to dietary carbohydrate level but exhibited a marked difference in secretion of this enzyme into the gut. Results are discussed to highlight the limitations to increasing carbohydrate utilization by lobsters. Further growout trials are needed to link the presented metabolic profiles with phenotypic outcomes. PMID:29114440

Carbohydrates and Endothelial Function: Is a Low-Carbohydrate Diet or a Low-Glycemic Index Diet Favourable for Vascular Health?

PubMed Central

Jovanovski, Elena; Zurbau, Andreea

2015-01-01

Low-carbohydrate diets have become increasingly popular in both media and clinical research settings. Although they may improve some metabolic markers, their effects on arterial function remain unclear. Endothelial dysfunction is the well-established response to cardiovascular risk factors and a pivotal feature that precedes atherosclerotic diseases. It has been demonstrated that a high carbohydrate-induced hyperglycemia and subsequent oxidative stress acutely worsen the efficacy of the endothelial vasodilatory system. Thus, in theory, a carbohydrate restricted diet may preserve the integrity of the arterial system. This review attempts to provide insight on whether low-carbohydrate diets have a favorable or detrimental impact on vascular function, or it is perhaps the quality of carbohydrate that should direct dietary recommendations. Research to date suggests that diets low in carbohydrate amount may negatively impact vascular endothelial function. Conversely, it appears that maintaining recommended carbohydrate intake with utilization of low glycemic index foods generates a more favorable vascular profile. Understanding these relationships will aid in deciphering the diverging role of modulating quantity and quality of carbohydrates on cardiovascular risk. PMID:25954727

Carbohydrates and endothelial function: is a low-carbohydrate diet or a low-glycemic index diet favourable for vascular health?