Coloration in the polymorphic frog Oophaga pumilio associates with level of aggressiveness in intraspecific and interspecific behavioral interactions

© 2015, Springer-Verlag Berlin Heidelberg. Intraspecific morphological variation may correspond to behavioral variation that helps determine the nature of species interactions. Color variation among populations of variably toxic organisms has been shown to associate with alternative anti-predator behaviors. However, the effects of these alternative behavioral tendencies on the outcomes of interspecific interactions other than predator–prey remain largely unexplored. We investigated how coloration and body size variation in Oophaga pumilio, one of the most phenotypically diverse amphibians known, associated with territorial aggressiveness and how this association influenced the outcome of agonistic male–male interactions with conspecifics and heterospecifics of two sympatric species (Andinobates claudiae and Phyllobates lugubris). Irrespective of body size, resident frogs from more conspicuous, red-colored O. pumilio populations responded to same-morph conspecifics and P. lugubris more quickly and exhibited more aggressive behaviors and more energetically expensive behaviors than resident frogs from green populations under these same treatments. Furthermore, red-colored resident frogs dominated most of the interactions in which they were involved, whereas green residents dominated only a few of the interactions, despite their status as residents. Because conspecific and heterospecific intruders did not behave more aggressively toward red resident frogs, aggressiveness of red residents does not appear to be a response to higher aggression being directed toward them. These results suggest that coloration in O. pumilio is a good indicator of aggressiveness that associates with the outcome of intraspecific and some interspecific behavioral male–male interactions, providing support for a positive association among anti-predator traits, agonistic behavior, and dominance in both intraspecific and interspecific, intraguild interactions

Modulating the water behavior, microstructure, and viscoelasticity of plasma-derived hydrogels by adding silica nanoparticles with tailored chemical and colloidal properties

The viscoelastic properties of hydrogels depend on the tridimensional polymeric structure and the behavior of the liquid confined in their pores. The objective here is to modulate these characteristics in plasma-derived hydrogels by the addition of glycidoxypropyl-silica nanoparticles. These nanoparticles exhibited a hydrodynamic average size between 105.4 − 151.0 nm and surface coverage with (3-Glycidoxypropyl) trimethoxysilane of 0–96 %. The reinforced hydrogels are porous networks with spherical nanoparticles homogeneously distributed into their walls. The silanol groups of silica increase four-fold humidity retention compared with the native hydrogel. This correlates with bound water &gt; 45 % on these reinforced hydrogels, in contrast with 75 % of free water on the native one (calculated from DSC in frozen hydrogels). The humidity stability can be also achieved in the hydrogel prepared with nanoparticles exhibiting 96 % organic coverage. Furthermore, this organic content promotes the microstructure chemical crosslinking, resulting in 3.9 and 1.6 higher Young's modulus compared with native and silica-reinforced hydrogels, respectively. The presence of glycidoxypropyl-silica nanoparticles in reinforced hydrogels modulated its viscoelasticity behavior, decreasing stress relaxation, which was explained using the generalized Maxwell-Wiechert model. In conclusion, novel organic-inorganic hybrid hydrogels based on plasma-derived ones and glycidoxypropyl-silica nanoparticles were developed. These nanoparticles are versatile and allow the production of hydrogels with improved viscoelastic behavior that also exhibits high water retention and morphological stability.</p

Modulating the water behavior, microstructure, and viscoelasticity of plasma-derived hydrogels by adding silica nanoparticles with tailored chemical and colloidal properties

The viscoelastic properties of hydrogels depend on the tridimensional polymeric structure and the behavior of the liquid confined in their pores. The objective here is to modulate these characteristics in plasma-derived hydrogels by the addition of glycidoxypropyl-silica nanoparticles. These nanoparticles exhibited a hydrodynamic average size between 105.4 − 151.0 nm and surface coverage with (3-Glycidoxypropyl) trimethoxysilane of 0–96 %. The reinforced hydrogels are porous networks with spherical nanoparticles homogeneously distributed into their walls. The silanol groups of silica increase four-fold humidity retention compared with the native hydrogel. This correlates with bound water &gt; 45 % on these reinforced hydrogels, in contrast with 75 % of free water on the native one (calculated from DSC in frozen hydrogels). The humidity stability can be also achieved in the hydrogel prepared with nanoparticles exhibiting 96 % organic coverage. Furthermore, this organic content promotes the microstructure chemical crosslinking, resulting in 3.9 and 1.6 higher Young's modulus compared with native and silica-reinforced hydrogels, respectively. The presence of glycidoxypropyl-silica nanoparticles in reinforced hydrogels modulated its viscoelasticity behavior, decreasing stress relaxation, which was explained using the generalized Maxwell-Wiechert model. In conclusion, novel organic-inorganic hybrid hydrogels based on plasma-derived ones and glycidoxypropyl-silica nanoparticles were developed. These nanoparticles are versatile and allow the production of hydrogels with improved viscoelastic behavior that also exhibits high water retention and morphological stability.</p

Modulating the water behavior, microstructure, and viscoelasticity of plasma-derived hydrogels by adding silica nanoparticles with tailored chemical and colloidal properties

The viscoelastic properties of hydrogels depend on the tridimensional polymeric structure and the behavior of the liquid confined in their pores. The objective here is to modulate these characteristics in plasma-derived hydrogels by the addition of glycidoxypropyl-silica nanoparticles. These nanoparticles exhibited a hydrodynamic average size between 105.4 − 151.0 nm and surface coverage with (3-Glycidoxypropyl) trimethoxysilane of 0–96 %. The reinforced hydrogels are porous networks with spherical nanoparticles homogeneously distributed into their walls. The silanol groups of silica increase four-fold humidity retention compared with the native hydrogel. This correlates with bound water &gt; 45 % on these reinforced hydrogels, in contrast with 75 % of free water on the native one (calculated from DSC in frozen hydrogels). The humidity stability can be also achieved in the hydrogel prepared with nanoparticles exhibiting 96 % organic coverage. Furthermore, this organic content promotes the microstructure chemical crosslinking, resulting in 3.9 and 1.6 higher Young's modulus compared with native and silica-reinforced hydrogels, respectively. The presence of glycidoxypropyl-silica nanoparticles in reinforced hydrogels modulated its viscoelasticity behavior, decreasing stress relaxation, which was explained using the generalized Maxwell-Wiechert model. In conclusion, novel organic-inorganic hybrid hydrogels based on plasma-derived ones and glycidoxypropyl-silica nanoparticles were developed. These nanoparticles are versatile and allow the production of hydrogels with improved viscoelastic behavior that also exhibits high water retention and morphological stability.</p

Modulating the water behavior, microstructure, and viscoelasticity of plasma-derived hydrogels by adding silica nanoparticles with tailored chemical and colloidal properties

The viscoelastic properties of hydrogels depend on the tridimensional polymeric structure and the behavior of the liquid confined in their pores. The objective here is to modulate these characteristics in plasma-derived hydrogels by the addition of glycidoxypropyl-silica nanoparticles. These nanoparticles exhibited a hydrodynamic average size between 105.4 − 151.0 nm and surface coverage with (3-Glycidoxypropyl) trimethoxysilane of 0–96 %. The reinforced hydrogels are porous networks with spherical nanoparticles homogeneously distributed into their walls. The silanol groups of silica increase four-fold humidity retention compared with the native hydrogel. This correlates with bound water &gt; 45 % on these reinforced hydrogels, in contrast with 75 % of free water on the native one (calculated from DSC in frozen hydrogels). The humidity stability can be also achieved in the hydrogel prepared with nanoparticles exhibiting 96 % organic coverage. Furthermore, this organic content promotes the microstructure chemical crosslinking, resulting in 3.9 and 1.6 higher Young's modulus compared with native and silica-reinforced hydrogels, respectively. The presence of glycidoxypropyl-silica nanoparticles in reinforced hydrogels modulated its viscoelasticity behavior, decreasing stress relaxation, which was explained using the generalized Maxwell-Wiechert model. In conclusion, novel organic-inorganic hybrid hydrogels based on plasma-derived ones and glycidoxypropyl-silica nanoparticles were developed. These nanoparticles are versatile and allow the production of hydrogels with improved viscoelastic behavior that also exhibits high water retention and morphological stability.</p

Modulating the water behavior, microstructure, and viscoelasticity of plasma-derived hydrogels by adding silica nanoparticles with tailored chemical and colloidal properties

The viscoelastic properties of hydrogels depend on the tridimensional polymeric structure and the behavior of the liquid confined in their pores. The objective here is to modulate these characteristics in plasma-derived hydrogels by the addition of glycidoxypropyl-silica nanoparticles. These nanoparticles exhibited a hydrodynamic average size between 105.4 − 151.0 nm and surface coverage with (3-Glycidoxypropyl) trimethoxysilane of 0–96 %. The reinforced hydrogels are porous networks with spherical nanoparticles homogeneously distributed into their walls. The silanol groups of silica increase four-fold humidity retention compared with the native hydrogel. This correlates with bound water &gt; 45 % on these reinforced hydrogels, in contrast with 75 % of free water on the native one (calculated from DSC in frozen hydrogels). The humidity stability can be also achieved in the hydrogel prepared with nanoparticles exhibiting 96 % organic coverage. Furthermore, this organic content promotes the microstructure chemical crosslinking, resulting in 3.9 and 1.6 higher Young's modulus compared with native and silica-reinforced hydrogels, respectively. The presence of glycidoxypropyl-silica nanoparticles in reinforced hydrogels modulated its viscoelasticity behavior, decreasing stress relaxation, which was explained using the generalized Maxwell-Wiechert model. In conclusion, novel organic-inorganic hybrid hydrogels based on plasma-derived ones and glycidoxypropyl-silica nanoparticles were developed. These nanoparticles are versatile and allow the production of hydrogels with improved viscoelastic behavior that also exhibits high water retention and morphological stability.</p

Modulating the water behavior, microstructure, and viscoelasticity of plasma-derived hydrogels by adding silica nanoparticles with tailored chemical and colloidal properties

The viscoelastic properties of hydrogels depend on the tridimensional polymeric structure and the behavior of the liquid confined in their pores. The objective here is to modulate these characteristics in plasma-derived hydrogels by the addition of glycidoxypropyl-silica nanoparticles. These nanoparticles exhibited a hydrodynamic average size between 105.4 − 151.0 nm and surface coverage with (3-Glycidoxypropyl) trimethoxysilane of 0–96 %. The reinforced hydrogels are porous networks with spherical nanoparticles homogeneously distributed into their walls. The silanol groups of silica increase four-fold humidity retention compared with the native hydrogel. This correlates with bound water &gt; 45 % on these reinforced hydrogels, in contrast with 75 % of free water on the native one (calculated from DSC in frozen hydrogels). The humidity stability can be also achieved in the hydrogel prepared with nanoparticles exhibiting 96 % organic coverage. Furthermore, this organic content promotes the microstructure chemical crosslinking, resulting in 3.9 and 1.6 higher Young's modulus compared with native and silica-reinforced hydrogels, respectively. The presence of glycidoxypropyl-silica nanoparticles in reinforced hydrogels modulated its viscoelasticity behavior, decreasing stress relaxation, which was explained using the generalized Maxwell-Wiechert model. In conclusion, novel organic-inorganic hybrid hydrogels based on plasma-derived ones and glycidoxypropyl-silica nanoparticles were developed. These nanoparticles are versatile and allow the production of hydrogels with improved viscoelastic behavior that also exhibits high water retention and morphological stability.</p

Estudio de la especiación de disoluciones hidrolizadas mixtas Al-Fe en medio concentrado con el reactivo Ferrón.

Introducción. La obtención de disoluciones concentradas de aluminio con alta fracción de oligocationes presenta gran interés por su aplicabilidad como floculantes en el tratamiento de aguas y como agentes de intercalación de arcillas laminares. El análisis espectrofotométrico con el reactivo Ferrón permite obtener una distribución de las especies que se generan en disoluciones parcialmente hidrolizadas de Al3+, en base a su grado de polimerización. El propósito de este trabajo es evaluar el efecto de la relación de hidrólisis OH/(Al+Fe) (RH) y la concentración total de metales (CTM) sobre la preparación de disoluciones hidrolizadas de Al/Fe en medio concentrado. Para ello, se toma como criterio el contenido de los metales que queda representado al final en especies tipo Keggin (Al13), correspondiente a la fracción Alb obtenida mediante el análisis con el reactivo Ferrón [1]. Metodología. El efecto de la CTM y de la RH sobre la preparación de las disoluciones concentradas mixtas Al/Fe (DCMAF), se evaluó aplicando un diseño experimental 32, manteniendo constante la relación atómica nominal (Fe/(Al+Fe)) igual a 2,0. Cada factor se evaluó en tres niveles: para el factor CTM se emplearon los valores 0,2, 0,6 y 1,0 mol/L, mientras para el factor RH se tomaron los valores 2,0, 2,25 y 2,5. La preparación de las disoluciones se llevó a cabo partiendo de AlCl3.6H2O (Sigma Aldrich, 99,9%) y FeCl3.6H2O (Mallinckrodt, 99,5%) con lenta adición de disolución de hidróxido de sodio de concentración variable (Mallinckrodt, 99,8%), en un sistema de reflujo a 70 ºC durante 7,75 horas. Las disoluciones fueron filtradas en papel con tamaño de poro 0,45 μm para separar la fracción insoluble antes de ser analizadas. Para el análisis con el reactivo Ferrón (Sigma Aldrich, 98,5%) se empleó como patrón una disolución de concentración conocida de Al13, separado por precipitación del sulfato seguida de disolución del nitrato del oligocatión. La identidad del patrón se confirmó por difracción de rayos X en polvo. Las fracciones de Ala y Alb se determinaron midiendo la absorbancia a 364 nm a 1 y 120 minutos de reacción, respectivamente. Ala corresponde a la fracción de especies monoméricas, Alb a la fracción oligomérica soluble, y Alc a la fracción polimérica coloidal, calculada como Alc = AlT – (Ala + Alb). Resultados y discusión. La distribución de especies obtenida mediante el análisis con el reactivo Ferrón se muestra en la tabla 1. Tabla 1. Especiación de disoluciones concentradas mixtas Al/Fe (DCMAF) Los resultados muestran que a menor RH se favorece la fracción de especies poliméricas solubles Alb, aunque este efecto es menos marcado en cuanto baja CTM. Igualmente se observa, que con el aumento en CTM, Alb disminuye para un valor de RH. Cuando se incrementa CTM también se puede observar, que aunque baja el pH de equilibrio de las disoluciones se incrementa la fracción de polímeros inertes o coloidales de los metales, que corresponde a la fracción Alc con Ferrón. Conclusiones. La preparación de DCMAF con alto contenido de Al13 en medio concentrado se favorece con la disminución de RH. Bibliografía. 1. Parker, D.R. (1992). Identification and quantification of the “Al13” tridecameric polycation using ferron. Env. Sci. Technol. 26:908–914. Agradecimientos. Los autores agradecen la financiación de este trabajo a EMPOPASTO S.A, E.S.P mediante convenio específico de cooperación No 01 de 2008

Antiparasitic Bromotyrosine Derivatives from the Marine Sponge Verongula rigida

Nine bromotyrosine-derived compounds were isolated from the Caribbean marine sponge Verongula rigida. Two of them, aeroplysinin-1 (1) and dihydroxyaerothionin (2), are known compounds for this species, and the other seven are unknown compounds for this species, namely: 3,5-dibromo-N,N,N-trimethyltyraminium (3), 3,5-dibromo-N,N,N, O-tetramethyltyraminium (4), purealidin R (5), 19-deoxyfistularin 3 (6), purealidin B (7), 11-hydroxyaerothionin (8) and fistularin-3 (9). Structural determination of the isolated compounds was performed using one- and two-dimensional NMR, MS and other spectroscopy data. All isolated compounds were screened for their in vitro activity against three parasitic protozoa: Leishmania panamensis, Plasmodium falciparum and Trypanosoma cruzi. Compounds 7 and 8 showed selective antiparasitic activity at 10 and 5 μM against Leishmania and Plasmodium parasites, respectively. Cytotoxicity of these compounds on a human promonocytic cell line was also assessed