Microplusin, a Rhipicephalus (Boophilus) microplus antimicrobial peptide (AMP) is the first fully characterized member of a new family of cysteine-rich AMPs with histidine-rich regions at the N and C termini. In the tick, microplusin belongs to the arsenal of innate defense molecules active against bacteria and fungi. Here we describe the NMR solution structure of microplusin and demonstrate that the protein binds copper II and iron II. Structured as a single ␣-helical globular domain, microplusin consists of five ␣-helices: ␣1 (residues Gly-9 to Arg-21), ␣2 (residues Glu-27 to Asn-40), ␣3 (residues Arg-44 to Thr-54), ␣4 (residues Leu-57 to Tyr-64), and ␣5 (residues Asn-67 to Cys-80). The N and C termini are disordered. This structure is unlike any other AMP structures described to date. We also used NMR spectroscopy to map the copper binding region on microplusin. Finally, using the Gram-positive bacteria Micrococcus luteus as a model, we studied of mode of action of microplusin. Microplusin has a bacteriostatic effect and does not permeabilize the bacterial membrane. Because microplusin binds metals, we tested whether this was related to its antimicrobial activity. We found that the bacteriostatic effect of microplusin was fully reversed by supplementation of culture media with copper II but not iron II. We also demonstrated that microplusin affects M. luteus respiration, a copper-dependent process. Thus, we conclude that the antibacterial effect of microplusin is due to its ability to bind and sequester copper II.

Polyamines are substances involved in many aspects of cell growth, division, and differentiation. Because of the metabolic differences between host cells and parasite cells, polyamine metabolism has been considered as a potential target for the chemotherapy of parasitic diseases. The aim of this work was to evaluate the schistosomicidal activity of different N-alkylated diamines (3a–3h), amino alcohols (4a–4d), and glycosylated amino alcohols (10a–10d). Compounds were prepared by synthetic methods and submitted to in vitro evaluation against adult worms of Schistosoma mansoni. At 100 μM, 3b, 3e, and 3h as well as 4a, 4b, 4d, 10a, 10b, and 10d resulted in 100% mortality of adult schistosomes. Compound 3d (12.5 to 100 μM) caused the death of 100% of both male and female adult schistosomes, while 3f (12.5 to 100 μM) resulted in 100% mortality of only male adult worms, whereas no mortality in female worms was observed. Compounds 3d and 3f were also able to reduce viability and decrease production of developed eggs in comparison with the negative control group. Diamines 3d and 3f may represent useful lead compounds for further optimization in order to develop new schistosomicidal agents.

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The experiments of carvedilol form II, form III, and hydrate by (13)C and (15)N cross-polarization magic-angle spinning (CP MAS) are reported. The GIPAW (gauge-including projector-augmented wave) method from DFT (density functional theory) calculations was used to simulate (13)C and (15)N chemical shifts. A very good agreement was found for the comparison between the global results of experimental and calculated nuclear magnetic resonance (NMR) chemical shifts for carvedilol polymorphs. This work aims a comprehensive understanding of carvedilol crystalline forms employing solution and solid-state NMR as well as DFT calculations.

Twenty analogues of the anti-HIV-1 integrase (IN) inhibitors dicaffeoylquinic acids (DCQAs) were prepared. Their IC(50) values for 3'-end processing and strand transfer against recombinant HIV-1IN were determined in vitro, and their cell toxicities and EC(50) against HIV-1 were measured in cells (ex vivo). Acetylated or benzylated and/or with cyclohexylidene group compounds exhibited no inhibition of integration in biochemical assays or viral replication in HIV-infected cells, with the exception of 16 and 36. Removal of these groups, however, correlated with potent inhibition. Compounds 19, 31, and 38, all digalloyls, exhibited the most robust inhibitory performance in biochemical assays as well as in cell culture and less toxicity than other molecules in the current study.