Following the treads of our previous works on the unveiling of bioactive peptides encrypted in plant proteins from diverse species, the present manuscript reports the occurrence of four proof-of-concept intragenic antimicrobial peptides in human proteins, named Hs IAPs. These IAPs were prospected using the software Kamal, synthesized by solid phase chemistry, and had their interactions with model phospholipid vesicles investigated by differential scanning calorimetry and circular dichroism. Their antimicrobial activity against bacteria, yeasts and filamentous fungi was determined, along with their cytotoxicity towards erythrocytes. Our data demonstrates that Hs IAPs are capable to bind model membranes while attaining α-helical structure, and to inhibit the growth of microorganisms at concentrations as low as 1μM. Hs02, a novel sixteen residue long internal peptide ( ) derived from the unconventional myosin 1h protein, was further investigated in its capacity to inhibit lipopolysaccharide-induced release of TNF-α in murine macrophages. Hs02 presented potent anti-inflammatory activity, inhibiting the release of TNF-α in LPS-primed cells at the lowest assayed concentration, 0.1 μM. A three-dimensional solution structure of Hs02 bound to DPC micelles was determined by Nuclear Magnetic Resonance. Our work exemplifies how the human genome can be mined for molecules with biotechnological potential in human health and demonstrates that IAPs are actual alternatives to antimicrobial peptides as pharmaceutical agents or in their many other putative applications.

In this contribution, we report an original photochemical method and its mechanism, in which Ag nanoparticles (AgNPs) are formed in the presence of starch. AgNO 3 /potato starch aqueous suspensions are irradiated (254 nm, 8 W) at room temperature and the Ag + /starch ratio can be varied to tune the size of AgNPs. The evolution of the AgNPs plasmon resonance band during the reaction is monitored by UV-Vis spectroscopy and evidences that AgNPs are formed in a two-stage process combining nucleation and growth, with the nucleation being controlled by the amount of added starch. Moreover, infrared and Raman spectra indicates that starch undergoes oxidation simultaneously to Ag + reduction, even though starch alone is not capable of reducing Ag + at an appreciable rate and UV irradiation is essential to produce sizeable amounts of AgNPs. Transmission electron microscopy reveals that AgNPs are nearly spherical with diameters ranging between 13 and 8 nm. The AgNPs/starch suspensions exhibit hydrodynamic diameters between 150 and 200 nm and zeta potentials very close to zero. Since AgNPs/starch suspensions are very stable over time, the colloidal stability is ensured by the steric hindrance imposed by starch rather than electrostatic repulsion.

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