The EgMUR3 xyloglucan galactosyltransferase from Eucalyptus grandis complements the mur3 cell wall phenotype in Arabidopsis thaliana

Xyloglucan is the major hemicellulosic polymer found in the primary cell walls of dicots. Xyloglucan tethers cellulose microfibrils conferring rigidity and strength for maintenance of cell integrity, and it is thought that its metabolism contributes to cell elongation and thus plant growth. Here, we have cloned and characterized a Eucalyptus grandis gene ortholog of the Arabidopsis thaliana MUR3 gene (xyloglucan galactosyltransferase), thus termed EgMUR3. EgMUR3 represents an intronless sequence of 1,854 bp predicted to encode a protein of 617 amino acid residues. It exhibits 73% identity and 82% similarity to the A. thaliana MUR3 gene. To demonstrate that this gene encodes a functional enzyme, the putative ORF was cloned into a binary vector under the control of a constitutive promoter and transformed into the A. thaliana mur3 mutant. The effect of the genetic complementation was investigated by xyloglucan oligosaccharide fingerprinting of wall material. The results confirmed that EgMUR3 represents indeed a xyloglucan galactosyltransferase of E. grandis able to use endogenous substrate(s) in A. thaliana, suggesting that both species share common steps in xyloglucan biosynthesis.     

Synthesis of chalcone analogues with increased antileishmanial activity

Eighteen analogues of an active natural chalcone were synthesized using xanthoxyline and some derivatives, and these analogues were tested for selective activity against both promastigotes and intracellular amastigotes of Leishmania amazonensis in vitro. Three analogues (10, 12, and 19) containing nitro, fluorine or bromine groups, respectively, displayed increased selective activity against the parasites as compared with the natural chalcone. The nitrosylated chalcone 10 was also tested intralesionally in infected mice and was found to be as effective as Pentostan reference drug at a dose 100 times higher than that of the chalcone in controlling both the lesion growth and the parasite burden.     

Xanthones and Cancer: from Natural Sources to Mechanisms of Action

Xanthones are a class of heterocyclic natural products that have been widely studied for their pharmacological potential. In fact, they have been serving as scaffolds for the design of derivatives focusing on drug development. One of the main study targets of xanthones is their anticancer activity. Several compounds belonging to this class have already demonstrated cytotoxic and antitumor effects, making it a promising group for further exploration. This review therefore focuses on recently published studies, emphasizing their natural and synthetic sources and describing the main mechanisms of action responsible for the anticancer effect of promising xanthones.     

Dynamic rheological properties of native and cross-linked gliadin proteins

A comparison of cross-linked and native gliadin suspensions, with respect to the state of protein globular structure was carried out using small-angle X-ray scattering (SAXS), dynamic light scattering (DLS) and rheological analysis. Gliadin suspensions were also analyzed in the presence and absence of glycerol. DLS analysis showed that R(h) increased only with gliadin/EDC/NHS suspensions. However, Kratky plots revealed that gliadin and gliadin/l-cysteine maintained their globular shape even in absence or presence of glycerol. Rheological experiments revealed that gliadin and gliadin/l-cysteine suspension exhibited a similar profile with three main domains, and a sol-gel transition. Gliadin/EDC/NHS did not present any sol-gel transition, and this fact corroborates with DLS results and the hypothesis of lower protein-protein interaction, which are in agreement with G″>G'.