Rambutan peel: An unconventional source of lignin and its potential applications in polymer science

This study aimed to evaluate the properties of soda lignin obtained from an unconventional and abundant waste - the rambutan peel - since lignin has been shown as the most promising natural organic feedstock alternative to petroleum for polymer science. FTIR analysis and pH measurements have confirmed the acidic form of lignin, which has shown solubility in a wide range of polarities and so many solvents, making its insertion easy on polymeric matrices. While the ability to absorb UV-light was higher than commercial lignin tested as reference, the morphology and size distribution at microscopic level were less regular than that. When added to a starch-based film, the lignin decreases its natural affinity for water, improving the barrier properties, as well as increasing its thermal resistance. Microorganisms could be developed easily on starch-based films containing this kind of lignin. This material, still underreported for technological applications, points towards as promisor to be a component or additive in polymeric matrices.

A soil-binding polysaccharide complex released from root hairs functions in rhizosheath formation

SUMMARYTo elucidate factors involved in rhizosheath formation, wild type (WT) barley (Hordeum vulgare L. cv. Pallas) and a root hairless mutant, bald root barley (brb), were investigated with a combination of physiological, biochemical and immunochemical assays. When grown in soil, WT barley roots bound ∼5-fold more soil than brb per unit root length. High molecular weight (HMW) polysaccharide exudates of brb roots had less soil-binding capacity than those of WT root exudates. Carbohydrate and glycan monoclonal antibody analyses of HMW polysaccharide exudates indicated differing glycan profiles. Relative to WT plants, root exudates of brb had reduced signals for arabinogalactan-protein (AGP), extensin and heteroxylan epitopes than brb. In contrast, the brb root exudate contained ∼25-fold more detectable xyloglucan epitope relative to WT. Epitope detection chromatography indicated that the increased detection of xyloglucan in brb exudates was due to enhanced abundance of a neutral polymer. Exudate preparations from brb had decreased amounts of an acidic form of xyloglucan associated with root-hair located glycoprotein and heteroxylan epitopes and with soil-binding properties. Therefore, in addition to physically structuring soil particles, root hairs facilitate rhizosheath formation by releasing a soil-binding polysaccharide complex.One sentence summaryThe root exudate of a root hairless mutant of barley, relative to wild type, has an altered pattern of polysaccharide epitopes and lesser amounts of an acidic soil-binding polysaccharide complex.

Preparation and characterization of Ni/mZSM-5 zeolite with a hierarchical pore structure by using KIT-6 as silica template: an efficient bi-functional catalyst for the reduction of nitro aromatic compounds

Ni/mZSM-5 hierarchical zeolite and the acidic form of it were prepared as novel bi-functional catalysts which showed excellent activity for reduction of nitro aromatic compounds in aqueous medium at room temperature.

Catalysis by substituted iron phthalocyanines of crystal violet leucobase oxidation with dioxygen

The catalytic reaction of crystal violet leucobase oxidation by dioxygen in o-dichlorobenzene into corresponding dye was studied as a model of hydrocarbons C – H group oxidation. Substituted iron phthalocyanines in acidic form HPcFeX were used as the catalysts. It was shown that the oxidation process was accompanied in all cases by autocatalytic destruction of catalyst with induction period depending on concentrations of reactants. The kinetics of dye formation and catalyst degradation, as well as the effect of radical reaction inhibitors were studied. The nature of the process main stages was proposed.

Phosphorylated and non-phosphorylated forms of catechol O-methyltransferase in rat liver, brain and other tissues

Seven different forms of the enzyme COMT (catechol O-methyltransferase) were found in isolated rat hepatocytes by two-dimensional gel electrophoresis and immunoblotting: five small variants (S-COMT) and two large variants (L-COMT). The identities of these COMT forms were verified by tryptic fingerprinting using MALDI–TOF (matrix-assisted laser-desorption ionization–time-of-flight) MS, and by amino acid sequencing using ESI–IT–MS/MS (electrospray ionization with ion-trap tandem MS). Analysis of tissue distributions showed that the S-COMT forms were highly expressed in liver and kidney, whereas L-COMT was expressed more strongly in other tissues. Both of the L-COMT forms were found in all of the tissues examined except the heart, which expressed only the most acidic form, and the kidney, which expressed only the most basic form. Subcellular fractionation revealed the presence of both S-COMT and L-COMT in soluble, as well as sedimentable, fractions, suggesting that they should be classified by size rather than (as previously) by localization. Several of the S-COMT forms were N-acetylated, and the two most acidic forms were found to be phosphorylated at Ser260. One of the latter was unique to liver cells; the other was also found in kidney, brain and thymus. Among the non-phosphorylated S-COMT forms, one was ubiquitous, one was found in testis and liver, and a third was found in liver, kidney and thymus. No other phosphorylated sites were found, suggesting that the pI differences distinguishing between the various COMT forms are due to some as yet unidentified structural modification(s).

The Post-translational Modifications of Proliferating Cell Nuclear Antigen

The diverse function of proliferating cell nuclear antigen (PCNA) is thought to be due, in large part, to post-translational modifications. Here we show by high resolution two-dimensional PAGE analysis that there are three distinct PCNA isoforms that differ in their acetylation status. The moderately acetylated main (M) form was found in all of the subcellular compartments of cycling cells, whereas the highly acetylated acidic form was primarily found in the nucleoplasm, nuclear matrix, and chromatin. Interestingly, the deacetylated basic form was most pronounced in the nucleoplasm of cycling cells. The cells in G0and the cytoplasm of cycling cells contained primarily the M form only. Because p300 and histone deacetylase (HDAC1) were co-immunoprecipitated with PCNA, they are likely responsible for the acetylation and deacetylation of PCNA, respectively. We also found that deacetylation reduced the ability of PCNA to bind to DNA polymerases β and δ. Taken together, our data support a model where the acidic and M forms participate in DNA replication, whereas the basic form is associated with the termination of DNA replication.