Carbohydrate Matrix Research Articles

Cow's Milk Bioactive Molecules in the Regulation of Glucose Homeostasis in Human and Animal Studies.

Obesity disrupts glucose metabolism, leading to insulin resistance (IR) and cardiometabolic diseases. Consumption of cow's milk and other dairy products may influence glucose metabolism. Within the complex matrix of cow's milk, various carbohydrates, lipids, and peptides act as bioactive molecules to alter human metabolism. Here, we summarize data from human studies and rodent experiments illustrating how these bioactive molecules regulate insulin and glucose homeostasis, supplemented with in vitro studies of the mechanisms behind their effects. Bioactive carbohydrates, including lactose, galactose, and oligosaccharides, generally reduce hyperglycemia, possibly by preventing gut microbiota dysbiosis. Milk-derived lipids of the milk fat globular membrane improve activation of insulin signaling pathways in animal trials but seem to have little impact on glycemia in human studies. However, other lipids produced by ruminants, including polar lipids, odd-chain, trans-, and branched-chain fatty acids, produce neutral or contradictory effects on glucose metabolism. Bioactive peptides derived from whey and casein may exert their effects both directly through their insulinotropic effects or renin-angiotensin-aldosterone system inhibition and indirectly by the regulation of incretin hormones. Overall, the results bolster many observational studies in humans and suggest that cow's milk intake reduces the risk of, and can perhaps be used in treating, metabolic disorders. However, the mechanisms of action for most bioactive compounds in milk are still largely undiscovered.

Impact of Wall Material-to-Active Ratio in the Stability of Spray-Dried Ascorbic Acid Using Maltodextrin and Gum Arabic.

Encapsulation revolutionizes industries through enhanced stability, controlled release, and targeted performance of active ingredients. The novel aspect of this study explores the impact of the wall material-to-active (WM:A) ratio on the stability of ascorbic acid (AA) encapsulated in a maltodextrin (MD) and gum arabic (GA) blend (2:1 w/w). Microparticles were spray-dried and analyzed using SEM, TGA, DSC, thermal stability, and antioxidant activity assessments. Stability tests under different conditions revealed that a higher WM:A ratio (7:1) improved the active stability and antioxidant activity during storage, highlighting its importance in the encapsulation process. SEM analysis confirmed particles with no cracks, and the particles demonstrated excellent thermal stability up to 200 °C with minimal degradation. These findings underscore the critical role of the WM:A ratio in determining the stability of encapsulated AA within a carbohydrate matrix, offering valuable insights for advancing encapsulation technologies.

Enzyme-Linked Lipid Nanocarriers for Coping Pseudomonal Pulmonary Infection. Would Nanocarriers Complement Biofilm Disruption or Pave Its Road?

Cystic fibrosis (CF) is associated with pulmonary Pseudomonas aeruginosa infections persistent to antibiotics. To eradicate pseudomonal biofilms, solid lipid nanoparticles (SLNs) loaded with quorum-sensing-inhibitor (QSI, disrupting bacterial crosstalk), coated with chitosan (CS, improving internalization) and immobilized with alginate lyase (AL, destroying alginate biofilms) were developed. SLNs (140-205 nm) showed prolonged release of QSI with no sign of acute toxicity to A549 and Calu-3 cells. The CS coating improved uptake, whereas immobilized-AL ensured >1.5-fold higher uptake and doubled SLN diffusion across the artificial biofilm sputum model. Respirable microparticles comprising SLNs in carbohydrate matrix elicited aerodynamic diameters MMAD (3.54, 2.48 µm) and fine-particle-fraction FPF (65, 48%) for anionic and cationic SLNs, respectively. The antimicrobial and/or antibiofilm activity of SLNs was explored in Pseudomonas aeruginosa reference mucoid/nonmucoid strains as well as clinical isolates. The full growth inhibition of planktonic bacteria was dependent on SLN type, concentration, growth medium, and strain. OD measurements and live/dead staining proved that anionic SLNs efficiently ceased biofilm formation and eradicated established biofilms, whereas cationic SLNs unexpectedly promoted biofilm progression. AL immobilization increased biofilm vulnerability; instead, CS coating increased biofilm formation confirmed by 3D-time lapse confocal imaging. Incubation of SLNs with mature biofilms of P. aeruginosa isolates increased biofilm density by an average of 1.5-fold. CLSM further confirmed the binding and uptake of the labeled SLNs in P. aeruginosa biofilms. Considerable uptake of CS-coated SLNs in non-mucoid strains could be observed presumably due to interaction of chitosan with LPS glycolipids in the outer cell membrane of P. aeruginosa. The biofilm-destructive potential of QSI/SLNs/AL inhalation is promising for site-specific biofilm-targeted interventional CF therapy. Nevertheless, the intrinsic/extrinsic fundamentals of nanocarrier-biofilm interactions require further investigation.

Combined pH ratiometry and fluorescence lectin-binding analysis (pH-FLBA) for microscopy-based analyses of biofilm pH and matrix carbohydrates.

Bacterial biofilms have a complex and heterogeneous three-dimensional architecture that is characterized by chemically and structurally distinct microenvironments. Confocal microscopy-based pH ratiometry and fluorescence lectin-binding analysis (FLBA) are well-established methods to characterize pH developments and the carbohydrate matrix architecture of biofilms at the microscale. Here, we developed a combined analysis, pH-FLBA, to concomitantly map biofilm pH and the distribution of matrix carbohydrates in bacterial biofilms while preserving the biofilm microarchitecture. As a proof of principle, the relationship between pH and the presence of galactose- and fucose-containing matrix components was investigated in dental biofilms grown with and without sucrose. The pH response to a sucrose challenge was monitored in different areas at the biofilm base using the ratiometric pH-sensitive dye C-SNARF-4. Thereafter, the fucose- and galactose-specific fluorescently labeled lectins Aleuria aurantia lectin (AAL) and Morus nigra agglutinin G (MNA-G) were used to visualize carbohydrate matrix components in the same biofilm areas and their immediate surroundings. Sucrose during growth significantly decreased biofilm pH (P < 0.05) and increased the amounts of both MNA-G- and AAL-targeted matrix carbohydrates (P < 0.05). Moreover, it modulated the biofilm composition towards a less diverse community dominated by streptococci, as determined by 16S rRNA gene sequencing. Altogether, these results suggest that the production of galactose- and fucose-containing matrix carbohydrates is related to streptococcal metabolism and, thereby, pH profiles in dental biofilms. In conclusion, pH-FLBA using lectins with different carbohydrate specificities is a useful method to investigate the association between biofilm pH and the complex carbohydrate architecture of bacterial biofilms.IMPORTANCEBiofilm pH is a key regulating factor in several biological and biochemical processes in environmental, industrial, and medical biofilms. At the microscale, microbial biofilms are characterized by steep pH gradients and an extracellular matrix rich in carbohydrate components with diffusion-modifying properties that contribute to bacterial acid-base metabolism. Here, we propose a combined analysis of pH ratiometry and fluorescence lectin-binding analysis, pH-FLBA, to concomitantly investigate the matrix architecture and pH developments in microbial biofilms, using complex saliva-derived biofilms as an example. Spatiotemporal changes in biofilm pH are monitored non-invasively over time by pH ratiometry, while FLBA with lectins of different carbohydrate specificities allows mapping the distribution of multiple relevant matrix components in the same biofilm areas. As the biofilm structure is preserved, pH-FLBA can be used to investigate the in situ relationship between the biofilm matrix architecture and biofilm pH in complex multispecies biofilms.

Viscoelastic properties of decellularized and freeze-dried human dermis between −90°C and 40°C

BACKGROUND: Human donor skin is processed to make the acellular dermis matrix (ADM) for tissue repair and regeneration. There is no data on the viscoelastic properties of ADM at room and subzero temperatures. OBJECTIVE: The work evaluated the temperature dependence of viscoelastic properties of freeze-dried ADM. MATERIALS AND METHODS: Donor skin was de-epidermized, de-cellularized and freeze-dried with trehalose as the lyo-protectant. Glass transition of freeze-dried ADM was measured by differential scanning calorimeter (DSC), and viscoelastic properties were examined by dynamic mechanical analyzer (DMA). RESULTS: At the low moisture range (1.4 ± 0.5%), the glass transition temperature (Tg) of freeze-dried ADM was 90°C to 100°C. As the moisture content increased, the Tg decreased steadily. At the high moisture range (10.8 ± 2.9%), the Tg was 40°C to 60°C. There were large donor-to-donor variations in viscoelastic properties of freeze-dried ADM as demonstrated by the changes in storage modulus (G’), loss modulus (G”) and damping factor tan δ(G”/G’). However, the trends of the temperature dependence for G’, G” and tan δ were similar among all 8 donors. For each donor, changes in G’ and G” were relatively small between −90°C and 40°C, and G’ was at least one order of magnitude greater than G”. Two viscoelastic relaxations were observed in freeze-dried ADM, one at −20°C and the other at −60°C respectively. CONCLUSION: Freeze-dried ADM was protected in the glassy carbohydrate matrix. DMA observed two viscoelastic relaxations (i.e., α process at −20°C and β process at −60°C). Overall changes in G’ and G” of freeze-dried ADM were relatively small within one order of magnitude between −90°C and 40°C.

Carbohydrate Core-Shell Electrosprayed Microcapsules for Enhanced Oxidative Stability of Vitamin A Palmitate.

Vitamin A is an essential micronutrient that is readily oxidized. In this study, the encapsulation of vitamin A palmitate (AP) within a core-shell carbohydrate matrix by co-axial electrospray and its oxidative stability was evaluated. The electrosprayed core-shell microcapsules consisted of a shell of octenyl succinic anhydride (OSA) modified corn starch, maltose (Hi-Cap), and a core of ethyl cellulose-AP (average diameter of about 3.7 µm). The effect of different compounds (digestion-resistant maltodextrin, soy protein hydrolysate, casein protein hydrolysate, and lecithin) added to the base core-shell matrix formulation on the oxidative stability of AP was investigated. The oxidative stability of AP was evaluated using isothermal and non-isothermal differential scanning calorimetry (DSC), and Raman and Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy methods. The core-shell carbohydrate matrix minimizes the amount of AP present at the microparticle surface, thus protecting AP from oxidation. Furthermore, the most effective oxidation protection was achieved when casein protein hydrolysate was added to the core of the microcapsule due to hydrophobic and hydrogen bond interactions with AP and by the resistant maltodextrin in the shell, which acted as a filler. The utilization of ethanol as a solvent for the dispersion of the core compounds increased the hydrophobicity of the hydrolyzed proteins and contributed to the enhancement of their antioxidant ability. Both the carbohydrate core-shell microcapsule prepared by co-axial electrospray and the addition of oxidation protection compounds enhance the oxidative stability of the encapsulated AP.

Valorization of beetle infected spruce to produce textile fibers and biofuels: Environmental sustainability evaluated by life cycle assessment

To achieve a viable forest-based biorefinery, both the carbohydrate and lignin parts of the raw material should be valorized. While lignin-first approaches have successfully been applied to hardwoods, where up to 50% of the lignin –close to the ‘theoretical maximum yield’– has been transformed to valuable monophenols; limited studies have targeted softwoods. Softwood lignin comprises lower amount of beta-ether bonds and this results in lower theoretical and observed yields of monophenols in reductive catalytic fractionation (RCF): below 5 wt% yield of initial biomass has been reported. In this study, we use beetle infected spruce, a softwood, as raw material. A fast fractionation was developed to give a pulp and a lignin fraction in the absence of transition metal catalysts. The carbohydrate matrix was valorized to dissolving grade pulp in 37 wt% from biomass (86% yield), and successfully spun to Lyocell fibers. The lignin fraction was dissolved in furfural –operating as green ‘solubility-enhancing-agent’– to blend lignin in inert carrier liquids to promote controlled hydrotreatment to yield biofuels in 10 wt% (60% carbon yield) from initial biomass. Life cycle assessment (LCA) of the value-chain showed improved sustainability in several footprint categories compared to cotton production. Thus, upgrading of a considered forestry waste to high value textile fibers and biofuels has been achieved: in case of lignin beyond the ‘theoretical maximum yield’. This is an important step to mitigate a future growing demand of textiles without negatively affecting irrigation or land use.

Magnetic carbon nanocomposites via the graphitization of glucose and their induction heating

Carbon nanocomposites containing iron-based nanoparticles are attractive materials for the catalyst supports used for magnetic (induction) heating catalysis. The metallic, soft-magnetic iron nanoparticles provide local heating of the support in an alternating magnetic field and ensure rapid magnetic separation of the nanocomposite particles from reaction suspensions. In this work, magnetic carbon nanocomposites were prepared by annealing the precursor particles consisting of iron-oxide nanoparticles dispersed in a carbohydrate matrix. The annealing was conducted at 600 °C and 750 °C in an Ar atmosphere. At both temperatures the carbothermal reduction of iron oxide to Fe/Fe3C was observed; however, at the lower temperature the rate of reduction and the growth of the nanoparticles were considerably slower. The Fe3C was formed in negligible amounts only after a prolonged period of annealing at 600 °C. A detailed structural analysis showed that the Fe/Fe3C nanoparticles catalyze the graphitization of the carbonaceous precursor material already at 600 °C, resulting in the formation of a graphitic shell that surrounds them. This shell is tight enough to prevent the areal oxidation of the encapsulated Fe nanoparticles; their magnetic properties remained unchanged even after 1 year of storage under ambient conditions. At the higher annealing temperature, the growth of the Fe/Fe3C nanoparticles caused bursting of the graphitic shell and thus partially exposed their surfaces to the atmosphere. All the nanocomposites exhibited ferromagnetic behavior in accordance with their compositions. The nanocomposite that was predominantly composed of a graphitic shell, encapsulated Fe nanoparticles and a negligible amount of Fe3C, showed the highest specific absorption rate (760 W/gFe at 274 kHz), even at a relatively low AC-field amplitude (88 mT).

Soft X-ray and susceptibility based magnetic resonance imaging to map iron distribution in apples: initial results to model iron storage in water-deficient or dehydrated biological tissue

Radiology departments have contributed significantly to greenhouse gases including release of toxic imaging contrast media to environment. We feel Radiology also has several spectroscopy and imaging tools that may apply to monitor and support cleaner environmental goals. The current manuscript is one of the firsts to prompt Radiology to move in that direction by non-invasive imaging of bio metals that are less abundant in biological tissues but play key roles as co-factors in tissue structure and function. Conventional analytical tools are mostly invasive and cannot characterize the native oxidation states of bio metals. We chose carbohydrate matrix of metal-rich fruits and optimized two non-invasive imaging methods to detect changes in bio metal distribution as the samples were allowed to dry over time. It complements our prior work in Tomography Journal that demonstrated breakdown of specific radiological contrast media causing inflow of lanthanides and iodinated compounds to agricultural products and alter homeostasis by chelation and transmetallation. We observed that in the 20–30 keV range, that is at low end of clinical X-ray, commercial mammography detectors can detect alkali, alkaline earth, and transition metals in fruit samples irrespective of their oxidation states with appropriate X-ray filters utilizing preferential photoelectric absorption while high field magnetic resonance imagers (MRI) can localize paramagnetic states of certain minerals due to their ability to accelerate proton T2* decay and was used here to study biological tissues at different stages of dehydration. We also observed a central, radial shift of iron distribution from cortex toward the core for partially dried Apples indicative of porosity changes with de-moisturization. However, at this time our approach is unable to convincingly separate the susceptibility effects of paramagnetic bio metals from susceptibility effects of porosity changes during dehydration. We believe this work has two novel aspects: first, that MRI and X-ray could be used for complementary roles to map distribution of paramagnetics rich species, and secondly, ionic transport during heat processing of agricultural products or crops grown in arid land can be monitored for altered bio metal distribution by low energy X-ray as well as by high field MRI. In vivo applications may be possible to exploit MR susceptibility of native bio metals to localize abnormal iron distribution in neurodegeneration.

199 Revisiting Mechanisms, Methods, and Models for Altering Cell Wall Utilization for Ruminants

Abstract Several wild and domesticated ruminants rely almost exclusively on the complex carbohydrate matrix from the plant cell wall (PCW) as their primary energy source via volatile fatty acids produced through ruminal and some hindgut fermentation processes. The PCW comprises different proportions and types of polysaccharides, pectic substances, polyphenols (lignin, tannins), and amino-N compounds (amino acids, peptides, proteins) that impact its digestibility and nutritive value. Thus, understanding the biosynthetic formation of the PCW will shed some light on possible manipulation mechanisms (e.g., genetic selection, management, and fertilization) and processing methods (e.g., physical, chemical, or enzymatic treatments) to increase its digestibility, leading to better utilization of the PCW by the ruminant animal. Laboratory techniques must be developed, evaluated, and modified to accurately and reliably reflect the digestibility and nutritive value of PCW brought about by modern manipulation mechanisms or processing methods. The chemical determination of lignin and its association with carbohydrates still lack consensus, although acid detergent lignin has been demonstrated to behave uniformly as a nutritional entity. Spectroscopy (near-infrared and Raman) and in vitro gas production techniques have been adopted to assess plant chemical composition and nutritive value, but an incomplete understanding of the impacts caused by disrupting the PCW for sample processing still exists. The limitations of these laboratory techniques have partially led to their association with mathematical models to improve the explanation of fermentation dynamics. Different variations of multicompartmental and time- and age-dependent mathematical models based on gamma distribution have been proposed to determine the ruminal rates of degradation and passage of fiber. However, low-quality data due to inconsistent marker results used to determine passage rates and transit time of fiber in the gastrointestinal tract have hindered advancements and adoptions of the next generation of computer models to understand fiber degradation in the rumen. The association of mechanistic modeling and artificial intelligence will perhaps improve PCW nutritive value predictions.

Influence of thermochemical activation of wood on the physicochemical properties of lignin

The wood matrix is a lignin–carbohydrate nanobiocomposite, thermodynamically quasi-equilibrium heterogeneous system of biopolymers. Changing its thermodynamic equilibrium due to directed chemical and (or) physical impacts opens up new approaches to the study of plant objects. Thermochemical activation, including treatments in sub- (steam explosion) and supercritical conditions (supercritical fluid extraction) having similar mechanisms of action, is one such method. The effect of steam explosion is determined by two components — chemical (the catalytic effect of formed acetic and formic acid) and physical (a sharp adiabatic expansion). The main components of supercritical treatment are increased temperature and pressure in the CO2 medium with cosolvents. The chemical component of this treatment is due to the addition of chemical reagents. Such treatments lead to a change in the thermodynamic state and capillary-porous structure of the lignin–carbohydrate matrix, an increase in its heterogeneity, and the yield of extracted lignin preparations. Lignin is the most reactive component of the wood matrix, and these processes result in changes in its functional nature and reaction properties. Thus, the lignin sample extracted after steam explosion had the greatest increase in the content of phenolic hydroxyl (by 39 rel.%) and carboxyl (by 57 rel.%) groups. Change in the functional composition of lignin leads to a change in its redox state, characterized by the oxidative potential and free energy of oxidation. It was shown that lignin after steam explosion had the highest oxidative potential and the lowest value of the oxidation energy, which indicated the greatest change in its reactivity in redox interactions.

Imaging of Transmetallation and Chelation Phenomena Involving Radiological Contrast Agents in Mineral-Rich Fruits.

Exogenous heavy metals or non-metallic waste products, for example lanthanide or iodinated contrast media for radiological procedures, may interfere with the biochemical pools in patients and in common food sources, creating an excess buildup of exogenous compounds which may reach toxic levels. Although the mechanisms are unknown, our experiments were designed to test if this toxicity can be attributed to “transmetallation” or “chelation” reactions freeing up lanthanides or chelated transition metals in acidic fruits used as phantoms representing the biologically active and mineral-rich carbohydrate matrix. The rapid breakdown of stable contrast agents have been reported at a lower pH. The interaction of such agents with native metals was examined by direct imaging of contrast infused fresh apples and sweet potatoes using low energy X-rays (40–44 kVp) and by magnetic resonance imaging at 1.5 and 3T. The stability of the exogenous agents seemed to depend on endogenous counterions and biometals in these fruits. Proton spin echo MR intensity is sensitive to paramagnetic minerals and low energy X-ray photons are sensitively absorbed by photoelectric effects in all abundant minerals and were compared before and after the infusion of radiologic contrasts. Endogenous iron and manganese are believed to accumulate due to interactions with exogenous iodine and gadolinium in and around the infusion spots. X-ray imaging had lower sensitivity (detection limit approximately 1 part in 104), while MRI sensitivity was two orders of magnitude higher (approximately 1 part in 106), but only for paramagnetic minerals like Mn and Fe in our samples. MRI evidence of such a release of metal ions from the native pool implicates transmetallation and chelation reactions that were triggered by infused contrast agents. Since Fe and Mn play significant roles in the function of metalloenzymes, our results suggest that transmetallation and chelation could be a plausible mechanism for contrast induced toxicity in vivo.

Molecular self-organization of wood lignin-carbohydrate matrix.

The analysis of the state of research on the chemical composition, functional nature and structure of the main components of the lignin-carbohydrate matrix allows considering the wood substance as a thermodynamically self-organizing nanobiocomposite system. Features of biosynthesis of the wood matrix main biopolymers, the formation of their functional nature and structure determine the complex hierarchical organization of cell walls. The supramolecular level of biosynthesis considers the interaction of cell wall components. On the one hand, these are questions of dynamics of cell walls synthesis and processes of self-organization that control the formation of chaotic objects of biological origin; on the other hand, it is the question of thermodynamic compatibility of plant tissue components. Various models of structural organization are currently being considered, focusing on various features (biological, chemical, structural) of wood substance. At the same time, the lignin-carbohydrate matrix is a three-component system of natural polymers: lignin-hemicelluloses-cellulose, the state of which is described by specific values of thermodynamic parameters that characterize the degree of its stability. The new approach proposed in this paper allows considering the plant lignin-carbohydrate matrix from the standpoint of physical chemistry of polymer as quasi-equilibrium, thermodynamically limited ordered system of biopolymers. Thus, the biochemical processes of synthesis and self-organization lead to the formation of a complex multicomponent system of wood substance, considered as a nanobiocomposite. This determines the need to study the applicability of the fundamental cycle "structure-functional nature-properties" from the standpoint of physical chemistry of biopolymers both for the investigation of plant objects and for the development of modern technologies for complex processing based on the principles of "green chemistry".

A Model System to Analyze Cell:Cell and Cell:ECM Interactions

Studies of in vivo structures have been made possible through ex vivo cell culture systems. While two‐dimensional (2D) systems have long provided inexpensive means to test functionality of cells, three‐dimensional (3D) systems have been found to be more advantageous in providing accurate physiological response (i.e. in vivo tissue formation, increased differentiation, reduced proliferation, etc). One such technology that allows for a widely tunable extracellular matrix (ECM) is a hydrogel. Hydrogels have been proven useful in the advancements of drug delivery and tissue repair and engineering while also providing a solid molecular scaffold for cellular system modeling. Previously, our lab has observed a novel physiological response when cells were placed on top of a Collagen I hydrogel. Cells became long and thin while migrating on and through the hydrogel to form a ring‐like structure, a toroid. Interestingly, the developing toroid takes the shape of the well in which its formed. A toroid was not formed, however, with cells mixed into the hydrogel. In this case, there was an observed scaffold contraction with cells remaining uniformly distributed. Our recent studies expand on these findings by modeling cell:cell and cell:ECM interactions through the creation of single‐ and multi‐cellular environments within different hydrogel matrices. To date, we have used 9 formulations of matrices including three types of Collagen I (PureCol, Nutrigen, and Fibricol), Collagen III, Collagen V, Rat Tail Collagen, and three types of synthetic matrices (AlphaBioGel, Matrigel, and VitroGel3D) and used no less than 10 cell types including cancer cells, cardiac fibroblasts (NHFs), microvascular endothelial cells, and several types of stem cells (ADSCs).Each hydrogel was prepared using a different, optimized protocol for the specific matrices used. Matrix solution was placed in a 96 well plate (100μL/well) and 50,000 cells in media were placed on top of each stabilized gel. Gels were incubated at 37 °C for 24 hours. They were then fixed in 2% Paraformaldehyde (PFA) prior to immunofluorescence staining.A toroid is a structure created by cells cultured on top of a hydrogel. In our studies, all combinations of cell:cell:gel produced toroids except for various cancer cell lines (cells stayed spread through the hydrogel). When cells were cultured on Collagen V, no toroids were formed and the matrix was remodeled by cells, and VitroGel3D, carbohydrate matrix produced a scaffold containing cell clumps. The size of the toroids varied depending on the matrix which cells were cultured on. This suggests the possibility for optimizing the application for various protocols. Interestingly, when NHFs and ADSCs were co‐cultured on the same PureCol hydrogel, the ADSCs created florets within the toroid which was not observed in other multi‐cellular toroids. Confocal imaging showed cellular interactions in response to other cells and the changing ECM of hydrogels. Using this model of cellular interactions and programming, we can examine and explore [1] the understanding of early embryonic development and [2] the optimization of hydrogels for in vivo applications.Support or Funding InformationSPARC graduate research grant, Cook Biotech, FirstString Research Inc, NIH 2 P20‐RR016434‐06, NIH INBRE grant for South Carolina P20GM103499, R01 HL126747.

Instability of low-moisture carrageenans as affected by water vapor sorption at moderate storage temperatures

Isothermal microcalorimetry was used to study the exothermic heat flow caused by the absorption of water into carrageenans and a furcellaran, leading to their thermodynamic instability under moderate storage conditions (35 °C, τ = 12 h), where τ is the reaction time (h). The net heats evolved by furcellaran, ι-carrageenan, κ-carrageenan, and a mixture of κ/λ-carrageenan were 43.5 J/g, 45.9 J/g, 31.6 J/g, and 28.1 J/g, respectively. The pronounced exothermic behavior of furcellaran was attributed to the enthalpic association of water molecules with the thermally degraded carbohydrate matrix. The responses of a heat treatment of carrageenans at 55 °C, 85 °C, and 105 °C for 15 min on exothermic heat Q (J/g) at different water activities (aw = 0.26, 0.51, 0.76, and 1.0) were measured. The dependence of the net recorded heat Q on water activity can be satisfactorily approximated by the equation Q = a[1 − (1 − aw)b], where a and b are the coefficients found by the nonlinear least-squares method. It was concluded that carrageenans affected by excessive heat treatment should be preferably stored with limited water access.

Regulating water binding capacity and improving porous carbohydrate matrix's humectant and moisture proof functions by mixture of sucrose ester and Polygonatum sibiricum polysaccharide

The moisture stability of tobacco shred, a typical porous carbohydrate material, is very important during its processing, storage and smoking, moreover, it is sensitive to environmental conditions. Therefore, effect of sucrose esters (SEs) and sucrose ester/Polygonatum sibiricum polysaccharide mixture (SPMs) on the moisture retention and moisture resistance of tobacco shred was assessed. When SEs were added to tobacco shred, moisture resistance was significantly enhanced, whereas moisture holding capacity was attenuated. Contrarily, the addition of SPMs made moisture retention index (MRI) and moisture proof index (MPI) increase from 1.8910 to 2.1612 and from 1.9489 to 2.0665, respectively, revealing that SPMs improved the moisture retention and moisture proof ability of tobacco shred simultaneously. The monolayer moisture content (M0) was decreased by SEs and increased by SPMs. Low-field nuclear magnetic resonance (LF-NMR) analysis showed that during adsorption, SPMs reduced the interaction between tobacco shred and water via hydrophobic property of SEs; during desorption, SPMs promoted the interaction between tobacco shred and water through hydrophilic binding of polysaccharide, leading to the migration of immobilized water to bound state. The modeling of the isotherms and LF-NMR analysis clarified the mechanism why SPMs could improve moisture stability of tobacco.

Screening the impact of food co-digestion on lipolysis under sub-optimal intestinal conditions

The scarce literature about the effect of meal-factors have on lipids digestibility encouraged the present study, in which olive oil was co-digested with naturally fat-free matrices that were rich in carbohydrate (potato and bread) or protein (degreased fresh cheese, hake and turkey) in single, binary and ternary combinations. Digestion was simulated in vitro, and the effect of co-digestion on the release of free fatty acid (FFA) from oil lipolysis were measured by gas chromatography-mass spectrometry. Regarding total FFA release, higher values were found in carbohydrate-rich systems, especially in potato, than in those with protein matrices. Thus, when co-digesting a carbohydrate matrix in addition to one or two protein matrices, lipolysis was reduced. This finding was explained by the carbohydrate and protein ratio of the resulting combinations, as the release of FFA increased with the carbohydrate/protein ratio (R2 = 0.87, p < 0.001 in potato; R2 = 0.81, p = 0.04 in bread systems). This study supposes the first approach towards characterisation of lipid digestion regarding food matrix nutritional composition.

Ascorbic acid encapsulation in a glassy carbohydrate matrix via hot melt extrusion: Preparation and characterization

Abstract Hot melt extrusion technology using a twin-screw extruder was employed to obtain maltodextrin, maltodextrin-gum arabic and maltodextrin-trehalose based glassy extrudates containing ascorbic acid (dispersed phase). Ascorbic acid payload of all three formulations was more than 15.67 g/100 g extrudates while the ascorbic acid yield was above 97%. The glass transition temperature (Tg) of all extrudates was above 40 °C. The expansion ratio of the extrudates and Tg reduced due to the incorporation of trehalose and gum arabic to maltodextrins, respectively. The results of Scanning Electron Microscopy, X-ray diffraction and Fourier-transform Infrared Spectroscopy confirmed that the formulated feed material turned into a glassy state, whereas, ascorbic acid was uniformly dispersed throughout the glassy matrix. Extruded formulations showed a steady dissolution rate, therefore, having a role in controlling the dissolution rate of ascorbic acid.

A solid update on wood-forming enzymes.

Wood is an important renewable source of energy, and as such, it may offer a sustainable, cost-effective alternative to fossils fuels. Wood is the primary source of building materials and many other products, and a major trade market that continues to grow steadily (FAO, 2017). Perhaps an even more significant role of woody biomass is as a carbon sink, as developing wood cells represent one of the most important traps for atmospheric CO2 (Plomion et al., 2001). Carbohydrate-Active enZymes (CAZymes) play crucial roles in the formation and modification of the carbohydrate matrix that constitutes woody biomass (Mellerowicz and Sundberg, 2008). In this issue of The Plant Journal, Kumar et al. (2019) re-annotated and re-classified CAZyme genes in the latest version of the poplar (Populus trichocarpa) genome. The work was led by Ewa Mellerowicz, a professor at the Umeå Plant Science Centre (UPSC), Sweden. Her group studies cell wall formation in woody species. Vikash Kumar, first author in the paper, joined the Mellerowicz lab as a postdoc in 2014, after graduating from the University of Delhi, India. Kumar is interested in the circadian cycle of secondary cell wall biosynthesis. Mellerowicz's group was involved in the first CAZyme annotation in poplar (Geisler-Lee et al., 2009), based on the original poplar genome assembly. Since most of the gene models changed in the current assembly (v. 3.0), the group realized that the CAZyme annotation had become outdated and set out to reannotate it. For this endeavor, they teamed up with Bernard Henrissat, from Aix-Marseille University (Marseille, France), the creator and curator of the CAZY database. They also enlisted the support of bioinformaticians Nathaniel Street and Nicolas Delhomme, the creators and curators of PopGenIE database. Alongside Chanaka Mannapperuma, they were instrumental in retrieving transcriptomic and genomic data from Populus databases. The result is one of the best annotated CAZyme databases in plants, a valuable resource for scientists investigating the function and properties of CAZymes in woody species. The database redefined all members of the many CAZyme families and closely related expansins and classified them according to their predicted function (see Figure). The authors also compared the genetic diversity of CAZyme genes in poplar and Arabidopsis. They found that poplar has 1.6× more genes and that significant differences are specific to certain enzyme families. These differences may provide hypotheses for further studies about adaptations to perennial/woody versus annual/herbaceous lifestyles. In silico analyses of gene expression during wood formation based on published datasets (Sundell et al., 2017) revealed gene clusters not only according to unique expression patterns during wood formation, but also according to different metabolites. In addition, co-expression network analyses of known CAZyme genes alongside uncharacterized ones revealed novel genes involved in wood formation. A total of 471 CAZyme genes formed a co-expression network, which included many uncharacterized genes with putative functions in cell wall biosynthesis and other cellular processes during wood formation. The association between genes with known activity with genes from partially characterized families helps predict their functions. Using this “guide genes” approach, the authors analyzed the closest network neighbors of some known cell wall-related CAZymes. For instance, within the primary wall network, cellulose, pectin, and xyloglucan-related genes were used as guides. The resulting network included several putative xyloglucan and pectin biosynthesis-related genes, providing a rich source of candidate genes for further analyses. The network also included three members of the “auxiliary activities” family of CAZymes, within a clade that had not been previously characterized in the context of wood development. These are also candidates for further investigation and may suggest a role for new gene families in wood growth. The CAZyme database will help improve the interpretation of many transcriptomics and proteomics datasets from woody tissues. Mellerowicz's group plans to use the resource to study the dynamics of cell secondary wall biosynthesis in the developing wood during the diurnal cycle. They hope this resource will support the whole plant research community working on cell wall and carbohydrates.

The Relative Importance of Cell Wall and Lumen Phytoliths in Carbon Sequestration in Soil: A Hypothesis

There has been much interest in the possibility that phytoliths might sequester substantial amounts of carbon and might continue to do so in soils and sediments after the death of the plant. This may contribute to mitigating climate change. However, this idea is controversial and it is unclear how much carbon is sequestered in phytoliths. High values would suggest that sequestration on a global scale could be significant, but low values would indicate insignificant sequestration. Different methodologies in preparing phytoliths give different carbon concentrations. Little interest has been shown in determining which types of phytoliths are most important for carbon sequestration. There are two main types of phytolith in plants, the cell wall types which are formed on a carbohydrate matrix, and the cell lumen types which are not. A literature survey of transmission and scanning electron microscopy studies to determine which phytoliths are cell wall phytoliths was carried out. Cell wall silicification was common in most plant organs and throughout the plant kingdom. Macrohairs, prickle hairs, and the wall protrusion of papillae are certainly cell wall types. The primary cell walls of many epidermal cells types are often silicified. Cell wall phytoliths have considerably higher carbon concentrations than lumen types. An attempt is made to model mixtures of cell wall and lumen phytoliths, containing different carbon concentrations. Literature data on carbon and nitrogen concentrations in phytoliths was used to produce C/N ratios. These showed that cell wall phytoliths had higher C/N ratios than lumen phytoliths, and that over-extraction of phytolith mixtures removes carbon preferentially from the cell wall types and leads to low C/N ratios. The dissolution of phytoliths in soils and sediments is considered, and it is unknown whether cell wall or lumen phytoliths break down faster. However, it is clear from the literature that cell wall phytoliths persist in soils and sediments for hundreds or thousands of years. The paper is brought to a climax with two hypotheses, one to explain what happens to carbon in phytoliths as they undergo preparatory procedures in the laboratory, and the other looking at dissolution and breakdown in the soil.