Piper gaudichaudianum Kunth (Piperaceae) accumulates gaudichaudianic acid, a prenylated benzopyran, as its major component. Interestingly, this trypanocidal compound occurs as a racemic mixture. Herein, transcriptomic investigations of Piper gaudichaudianum using the RNA-seq approach are reported, and from the analysis of the transcripts expressed it was possible to propose a complete biosynthetic pathway for the production of gaudichaudianic acid, including the steps that originate its precursor, p-hydroxybenzoic acid. Peperomia obtusifolia (L.) A. Dietr. (Piperaceae) also accumulates racemic benzopyrans, however, its chromanes originate from the polyketide pathway, while the chromenes from Piper derives from the shikimate pathway. Recent transcriptomic and proteomic studies of the former species did not identify polyketide synthases involved in the production of the benzopyran moiety, but revealed the expression of tocopherol cyclase, which may be responsible for the cyclization of the 3,4-dihydro-2H-pyran ring. The analysis of the enzymes involved in the secondary metabolism of Piper gaudichaudianum and the comparison with the data previously obtained from Peperomia obtusifolia can provide valuable information on how these compounds are biosynthesized.

Several protozoan parasites exist in the Trypanosomatidae family, including various agents of human diseases. Multiple lines of evidence suggest that important differences are present between the translational and mRNA processing (trans splicing) systems of trypanosomatids and other eukaryotes. In this context, certain small complexes of RNA and protein, which are named small nuclear ribonucleoproteins (U snRNPs), have an essential role in pre-mRNA processing, mainly during splicing. Even though they are well defined in mammals, snRNPs are still not well characterized in trypanosomatids. This study shows that a U5-15K protein is highly conserved among various trypanosomatid species. Tandem affinity pull-down assays revealed that this protein interacts with a novel U5-102K protein, which suggests the presence of a sub-complex that is potentially involved in the assembly of U4/U6-U5 tri-snRNPs. Functional analyses showed that U5-15K is essential for cell viability and is somehow involved with the trans and cis splicing machinery. Similar tandem affinity experiments with a trypanonosomatid U5-Cwc21 protein led to the purification of four U5 snRNP specific proteins and a Sm core, suggesting U5-Cwc-21 participation in the 35S U5 snRNP particle. Of these proteins, U5-200K was molecularly characterized. U5-200K has conserved domains, such as the DEAD/DEAH box helicase and Sec63 domains and displays a strong interaction with U5 snRNA.

Some cyclopalladated compounds containing the azido group ligand and the (C-N) ring of N,N-dimethylbenzylamine have been prepared by bridge opening reactions of dimmer azide complex precursor with some diphosphines in different stoichiometric quantities. The neutral or ionic, mono or binuclear complexes synthesized were characterized by elemental analyses, I. R. spectroscopy and NMR techniques. The series of complexes was screened for cytotoxicity against a panel three human tumour cells lines(C6,Hep-2,HeLa). All complexes were found to be cytotoxic (IC50) at µM concentrations while one complex having the coordination bond N-Pd ruptured also displayed some differential cytotoxicity.