Callose: a multifunctional (1, 3)-β–d-glucan involved in morphogenesis and function of angiosperm stomata

Background Although the cellulose microfibril organization in guard cell (GC) walls play a crucial role in the mechanism of the stomatal function, recent work showed that matrix cell wall materials are also involved. Especially in the kidney-shaped stomata of the fern Asplenium nidus, callose actively participates in the mechanism of opening and closure of the stomatal pore. Scope The present review briefly presents and discusses recent findings concerning the distribution and role of callose in the kidney-shaped stomata of the dicotyledon Vigna sinensis as well as in the dumbbell-shaped stomata of the monocotyledon Zea mays. Conclusion The discussed data support that, in both categories of angiosperm stomata, callose is implicated in the mechanism of stomatal pore formation and stomata function by locally affecting the mechanical properties of the GC cell walls.

Impact of Temperature, Ethanol and Cell Wall Material Composition on Cell Wall-Anthocyanin Interactions

The effects of temperature and ethanol concentration on the kinetics of anthocyanin adsorption and desorption interactions with five cell wall materials (CWM) of different composition were investigated. Using temperatures of 15 °C and 30 °C and model wine with ethanol concentrations of 0% and 15% (v/v) over 120 min, the adsorption and desorption rates of five anthocyanin-glucosides were recorded in triplicate. Small-scale experiments were conducted using a benchtop incubator to mimic a single berry fermentation. Results indicate that more than 90% of the adsorption occurs within the first 60 min of the addition of anthocyanins to CWM. However, desorption appears to occur much faster, with maximum desorption being reached after 30 min. The extent of both adsorption and desorption was clearly dependent not only on temperature and ethanol concentration but also on the CWM composition.

Study on Improving the Fixation Rate of Impregnated Poplar Wood with Maltodextrin and 1,3-Dimethylol-4,5-Dihydroxyethyleneurea

The impregnation of poplar wood (Populus adenopoda Maxim) with 1,3-dimethylol-4,5-dihydroxyethyleneurea and maltodextrin and the effects of ZnCl2 and curing at 103 °C and 120 °C on the fixation rate and the leaching resistance of modified samples were investigated (103 °C curing, ZnCl2 + 103 °C curing, 120 °C curing, and ZnCl2 + 120 °C curing are denoted as 103, ZC-103, 120, and ZC-120, respectively), with the aim of improving the modification effect. The results showed that ZC-103 had the highest fixation rate, and its weight leaching ratio was higher than that of 120. Fourier-transform infrared spectroscopy showed that ZnCl2 did not affect the functional groups of the modified chemicals. The flexural strength and modulus and the compressive strength perpendicular to the grain were highest for ZC-103. In summary, ZC-103 exhibited the highest fixation rate, indicating that the hardener ZnCl2 bridged and increased the interfacial properties between the chemicals and cell walls and therefore increased the potential for macromolecule polycondensation between the chemicals and cell wall materials. This research paves the way for improving the fixation rate of impregnated wood and provides new insights into practical applications.

Pharmacognostic Studies of the Stem Bark of Enantia chlorantha Oliver (Annonaceae)

Enantia chlorantha Oliver (Annonaceae) is commonly known as African yellow wood used as hepatoprotective, antiviral, antimalarial, antibacterial and antiulcer agents. The study was aimed to investigate the pharmacognostic and physiochemical parameters of E. chlorantha stem bark. The macroscopy, microscopy and chemomicroscopy of E. chlorantha were carried out using standard methods. Cell wall materials, cell inclusions and other diagnostic characters, which can aid in the easy and proper identification of the plant, were identified. The microscopic studies revealed the presence of sclereids, fibres, medullary ray, and calcium oxalate prisms. The physiochemical evaluation of was done, in order to ascertain quality and purity. This study provides additional useful information needed for determination of its identity and quality that can be added as enrichment of the pharmacopoeia of the plant.Keywords: Pharmacognostic, Stem Bark, Enantia chlorantha

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

ABSTRACTNorovirus (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.