Chelating properties of tripeptide-9 citrulline

Tripeptide-9 Citrulline (INCI name) is a peptide with skin care properties, used for cosmetic applications. In order to elucidate its mechanism of action in the chemical pathways that involve metal ions, its ability to complex such ions was investigated using spectrophotometrical, electrochemical and electrophoretical techniques. The obtained results using Cu(II) as metal ion were consistent with the formation of a complex between Tripeptide-9 Citrulline andCu(II). Cyclic voltammetry revealed a significant changein the electrochemical potentials. In-vitro electrophoretic studies served as a proof of concept that Tripeptide-9 Citrullinemay protect DNA from radical degradation induced by the Fenton reaction

Metal Ion-Binding Properties of 9-[(2-Phosphonomethoxy)ethyl]-2-aminopurine (PME2AP), an Isomer of the Antiviral Nucleotide Analogue 9-[(2-Phosphonometh¬oxy)ethyl]adenine (PMEA) : Steric Guiding of Metal Ion-Coordination by the Purine-Amino Group

The acidity constants of 3-fold protonated 9-[(2-phosphonomethoxy)ethyl]-2-aminopurine, H3(PME2AP)+, and the stability constants of the M(H;PME2AP)+ and M(PME2AP) complexes with M2+ = Ca2+, Mg2+, Mn2+, Co2+, Ni2+, Cu2+, Zn2+ or Cd2+ have been determined by potentiometric pH titrations in aqueous solution (25 °C; I = 0.1 M, NaNO3). It is concluded that in the M(H;PME2AP)+ species, the proton is at the phosphonate group and the metal ion at N7 of the purine residue. This “open” form allows macrochelate formation of M2+ with the monoprotonated phosphonate residue. The formation degree of this macrochelate amounts on average to 64 ± 13% (3σ) for those metal ions for which an evaluation was possible (Mn2+, Co2+, Ni2+, Cu2+, Zn2+). The identity of this formation degree indicates that the M2+/P(O)2−(OH) interaction occurs in an outersphere manner. The application of previously determined straight-line plots of log KMM(R-PO3)versus pKHH(R-PO3) for simple phosph(on)ate ligands, R-PO32−, where R represents a residue that does not affect metal ion binding, proves that all the M(PME2AP) complexes have larger stabilities than is expected for a sole phosphonate coordination of M2+. Combination with previous results allows the following conclusions: (i) The increased stability of the M(PME2AP) complexes of Ca2+, Mg2+ and Mn2+ is due to the formation of 5-membered chelates involving the ether-oxygen atom of the –CH2–O–CH2–PO32− residue; the formation degrees of these M(PME2AP)cl/O chelates for the mentioned metal ions vary between about 25% (Ca2+) to 40% (Mn2+). (ii) For the M(PME2AP) complexes of Co2+, Ni2+, Cu2+, Zn2+ or Cd2+ next to the mentioned 5-membered chelates a further isomer is formed, namely a macrochelate involving N7, M(PME2AP)cl/N7. The formation degrees of these macrochelates vary between about 30% (Cd2+) and 85% (Ni2+). (iii) The most remarkable observation of this study is that the shift of the NH2 group from C6 to C2 facilitates very significantly macrochelate formation of a PO32−-coordinated M2+ with N7 due to the removal of steric hindrance in the M(PME2AP) complexes. However, any M2+ interaction with N3 is completely suppressed, thus leading to significantly different coordination patterns than those observed previously with the antivirally active PMEA2− species

Efecto del policultivo en el establecimiento de tres gramíneas tropicales, en un suelo Vertisol del Valle del Cauto

Con el objetivo de evaluar la influencia del policultivo en el establecimiento de gramíneas, en un suelo Vertisol, se sembraron tres gramíneas tropicales (Panicum maximum cv. Likoni, Cenchrus ciliaris cv. Biloela y Chloris gayana cv. Callide) y cinco leguminosas (Vigna radiata, variedad frijol chino; y Vigna unguiculata, variedades: Cubanita-666, Lina, INIFAT-93 y IITA precoz) en sistemas de policultivo y monocultivo. El diseño fue de parcelas divididas, con cuatro réplicas. Las combinaciones de cultivos no afectaron el establecimiento de los pastos. Hubo interacción altamente significativa (p < 0,001) en el rendimiento de semilla de las gramíneas, así como en el rendimiento de grano de las leguminosas; con resultados sobresalientes en los policultivos de estas con P. maximum cv. Likoni, para el primer caso, y en V. radiata (frijol chino) combinada con P. maximum cv. Likoni y Ch. gayana cv. Callide, para el segundo. Todas las combinaciones presentaron ventajosos índices equivalentes del uso de la tierra, con valores superiores a uno. Se concluye que el uso de las leguminosas temporales en policultivo con las gramíneas no afectó su establecimiento, y que la cosecha de la semilla y de los granos mejoró la eficiencia biológica durante el proceso

Proyecto Binacional México-España: “Promoviendo y Generando Competencias Digitales para los Profesionales de la Salud”

Póster y vídeo presentados al 22 Congreso Nacional de Hospitales y Gestión Sanitaria celebrado en Málaga el 15-17 de septiembre de 2021Esta investigación ha sido apoyada por beca de la Fundación Pública Andaluza Progreso y Salud, y Fundación FIMABIS, Consejería de Salud de la Junta de Andalucía (EF-0401-2019).YesEsta propuesta se fundamenta en la premisa del Ministerio de Educación del Gobierno de España, la Unión Europea y la UNESCO, donde afirma que, la mayoría del personal de Salud debe reforzar sus habilidades digitales de consulta para mejorar sus buenas prácticas

Transformación digital y formación en competencias. Un proyecto de innovación educativa España-México

Póster y vídeo presentados al VI Congreso Internacional y XII Nacional de la Asociación de Enfermería Comunitaria (AEC). VIII Encuentro Nacional de Tutores y Residentes de Enfermería Familiar y Comunitaria celebrado en Sevilla 27, 28 y 29 de octubre de 2021Esta investigación ha sido apoyada por becas de la fundación pública Andaluza Progreso y Salud, y fundación FIMABIS, Consejería de Salud de la Junta de Andalucía (EF-0401-2019).YesLa crisis sanitaria y el distanciamiento social impuesto por la pandemia, ha puesto en evidencia la urgente necesidad que tienen los profesionales de adquirir competencias digitales, que les faculte para atender las tareas de éstos en el nuevo ecosistema de la información y la comunicación en la actual Sociedad del Conocimiento

Influence of decreasing solvent polarity (1,4-dioxane/water mixtures) on the stability and structure of complexes formed by copper(II), 2,2`-bipyridine or 1,10-phenanthroline and guanosine 5`-diphosphate : evaluation of isomeric equilibria

The stability constants of the 1 : 1 complexes formed between Cu(Arm)2+, where Arm = 2,2`-bipyridine or 1,10-phenanthroline, and guanosine 5`-diphosphate (GDP)3- or its monoprotonated form H(GDP)2- were determined by potentiometric pH titrations in water and in water containing 30 or 50 stability of the binary Cu(GDP)- complex is enhanced due to macrochelate formation of the diphosphate-coordinated Cu2+ with N7 of the guanine residue as previously shown. In Cu(Arm)(GDP)- the N7 is released from Cu2+ and the stability enhancement of more than one log unit in aqueous solution is clearly attributable to intramolecular stack formation between the aromatic rings of Arm and the guanine moiety. Indeed, stacked isomers occur to more than 90 with open unstacked forms. Surprisingly, the same formation degrees of the stacks are observed for Cu(Arm)(dGMP) complexes, where dGMP2- = 2`-deoxyguanosine 5`-monophosphate, despite the fact that the overall stability of the latter species is by about 2.7 log units lower. In 1,4-dioxane-water mixtures stack formation is drastically reduced, probably due to hydrophobic solvation of the aromatic rings by the ethylene bridges of 1,4-dioxane. The relevance of these results regarding biological systems is indicated