Ferulic Acid – A Versatile Molecule

The review summarizes the main roles of ferulic acid (4-hydroxy-3-methoxy-cinnamic acid), a phenolic compound widespread in the vegetable world, being present in cereals (rice, wheat, oats), coffee, tomatoes, nuts or corn, but also in a range of plants used in Traditional Chinese Medicine. It plays a vital role in ensuring cell wall rigidity and also in the formation of other important organic compounds for plants. Ferulic acid has a wide variety of biological activities such as: antioxidant, anti-inflammatory, antimicrobial, antiallergic, anticancer, antithrombotic, antiviral activities, vasodilator, hepatoprotective and metal chelation actions, enzymatic activity modulation, and wound healing activity. The most important action is the antioxidant one, being studies that demonstrate that ferulic acid acts synergistically with other antioxidants. Also, the antioxidant effect of ferulic acid is enhanced by skin exposure to ultraviolet light, making it a good ingredient for sunscreen cosmetics. It is one of the most powerful natural antioxidant that has the potential to neutralize free radicals, to slow down the aging process of the skin, to accelerate skin regeneration, to heal the skin wounds and also to preserve the health and beauty of the skin.

Plausible Mechanisms by Which Ultrasonic Waves Affect Seeds

To study the effect of sonication on the seed germination percentage and rate as well as the cell area of barley (Hordeum vulgare L.) a laboratorial experiment was performed as Completely Randomized Design (CRD) with 3 replications. The results indicated that the ultrasonic waves affect the seed germination, germination rate and cell area significantly (at 0.05). The results of the mean comparison tests (LSD, 0.05) showed that the highest germination percentage (100 %), germination rate and cell area (1370.71 μ2) is achieved through 15 minutes exposure to ultrasonic waves. It is concluded that weakening the seed’s cell wall rigidity by sonication results in more and faster water imbibition by the cells and improved germination.

The Glycosylphosphatidylinositol Anchor Biosynthesis Genes GPI12, GAA1, and GPI8 Are Essential for Cell-Wall Integrity and Pathogenicity of the Maize Anthracnose Fungus Colletotrichum graminicola

Glycosylphosphatidylinositol (GPI) anchoring of proteins is one of the most common posttranslational modifications of proteins in eukaryotic cells and is important for associating proteins with the cell surface. In fungi, GPI-anchored proteins play essential roles in cross-linking of β-glucan cell-wall polymers and cell-wall rigidity. GPI-anchor synthesis is successively performed at the cytoplasmic and the luminal face of the ER membrane and involves approximately 25 proteins. While mutagenesis of auxiliary genes of this pathway suggested roles of GPI-anchored proteins in hyphal growth and virulence, essential genes of this pathway have not been characterized. Taking advantage of RNA interference (RNAi) we analyzed the function of the three essential genes GPI12, GAA1 and GPI8, encoding a cytoplasmic N-acetylglucosaminylphosphatidylinositol deacetylase, a metallo-peptide-synthetase and a cystein protease, the latter two representing catalytic components of the GPI transamidase complex. RNAi strains showed drastic cell-wall defects, resulting in exploding infection cells on the plant surface and severe distortion of in planta–differentiated infection hyphae, including formation of intrahyphal hyphae. Reduction of transcript abundance of the genes analyzed resulted in nonpathogenicity. We show here for the first time that the GPI synthesis genes GPI12, GAA1, and GPI8 are indispensable for vegetative development and pathogenicity of the causal agent of maize anthracnose, Colletotrichum graminicola.

One-stage thermo-hydro treatment (THT) of hardwoods: an analysis of form stability after five soaking-drying cycles

A newly developed thermo-hydro treatment (THT) for use in a one-stage heat treatment process was examined by focusing on the form stability-related properties of European aspen (Populus tremula), birch silver (Betula pendula), and gray alder (Alnus incana). In particular, wood specimens were subjected to THT in a saturated steam atmosphere in a pilot-scale autoclave heated between 140 and 180°C for 1–3 h. Several parameters of untreated and treated samples after several soaking and drying cycles were compared, namely, the changes in the volumetric swelling, swelling in the radial and tangential directions, cell wall total water capacity, and anti-swelling efficiency (ASE). Due to repeated wetting in the cyclic water submersion-drying test, the original ASE of 73% decreased to 65% (180°C for 1 h), and the original ASE of 33% decreased to 5% (140°C for 1 h). Wood modified at 170°C presented good results that were not significantly lower than wood treated at higher temperatures while consuming less energy to deliver ASE improvement and was selected as optimum. To increase the ASE by 1%, the amount of energy consumed was decreased by 41%, 39%, and 17% compared with the treatment regimes of 160°C for 1 h, 160°C for 3 h, and 180°C for 1 h, respectively. The new THT regime led to improved long-term dimensional stability due to the cross-linking of cell wall polymers, which resulted in increased cell wall rigidity.

TheCandida albicansDse1 Protein Is Essential and Plays a Role in Cell Wall Rigidity, Biofilm Formation, and Virulence

The fungal pathogenCandida albicansis one of the leading causative agents of death in immunocompromised individuals. It harbors an arsenal of cell wall anchored factors that are implicated in virulence such as filamentation inducing factors, adhesins, lipases, proteases, and superoxide dismutases. Dse1 is a cell wall protein involved in cell wall metabolism. The purpose of this study is to characterize the role Dse1 plays in virulence. Dse1 appears to be an essential gene as no homozygous null mutant was possible. The heterozygote mutant exhibited increased susceptibility to calcofluor white, a cell wall disrupting agent, with a subsequent reduction in cell wall chitin content, decreased oxidative stress tolerance, a 30% reduction in biofilm formation, and a delay in adhesion that was mirrored by a reduction in virulence in a mouse model of infection. Dse1 thus appears to be an important protein involved in cell wall integrity and rigidity.

421 Thermodynamic Analysis on Mechanism of Deep Supercooling of Tissue Water in Winter-hardy Plants

It is known that the redistribution of water and the formation of dispersed water units appears to be a prerequisite for deep supercooling. A concentration of the cell solute results from the migration of water during extracelullar freezing and lowers the temperature of homogeneous nucleation, but we are convinced that nucleation of ice within cells may be initiated by a heterogeneous mechanism, except we consider a small spherical cave, the water can freeze on the wall of this cave. We are also convinced that the solid walls of the capillary exert an external potential on the water molecules, causing the shift of the triple point of the confined fluids. Based on Fletcher's work for spherical particle, we have gotten the formula of critical free energy in the process of heterogeneous nucleation of water in a small spherical cave. This presentation introduces the theoretical background and counts the drop of temperature in heterogeneous nucleation. Then, putting two actions (depression of triple point and process of heterogeneous nucleation) together, we have calculated the freezing point. Sometimes it is lower than –38 °C. Some phenomena can be explained by using this theory: 1) Water is at the tension status, which means that it wets plant tissue, so the triple point (melting point) of tissue water can be lowered. 2) The redistribution of water, formation of dispersed water units, and dry region preventing ice from propagating, all allow heterogeneous nucleation, then the two actions can be synthesized and the water would lead to deep supercooling. If the barriers were destroyed, heterogeneous nucleation and deep supercooling would certainly be lost. 3) This theory is only suited to rigid wall of small cave, so we understand why cell wall rigidity has been shown to affect freezing characteristics. Project 39870234 supported by National Nature Science Foundation.

LYSOZYME SENSITIVITY OF THE CELL WALL OF PSEUDO-MONAS AERUGINOSA: FURTHER EVIDENCE FOR THE ROLE OF THE NON-PEPTIDOGLYCAN COMPONENTS IN CELL WALL RIGIDITY

Electron micrographs of thin sections of normal cells of Pseudomonas aeruginosa showed the cell walls to be convoluted and to be composed of two distinct layers. Electron micrographs of thin sections of lysozyme-treated cells of P. aeruginosa showed (a) that the cell walls lost much of their convoluted nature; (b) that the layers of the cell walls became diffuse and less distinct; and (c) that the cell walls became separated from the protoplasts over extensive cellular areas. These results suggest that the peptidoglycan component of the unaltered cell walls of P. aeruginosa is sensitive to lysozyme. Furthermore, it appears that the peptidoglycan component is not solely responsible for the rigidity of the cell walls of Gram-negative bacteria.