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Hacer una presentación para un libro de poesía es como intentar preparar al lector para lo inasible. Es, de una forma muy particular, pretender que puede darse por anticipado la comprensión de unas frases que, precisamente, quieren escapar, que buscan estar más allá de una definición o de un mensaje. La poesía es esa paradoja: transmitir un sentido que siempre queda oculto, que es necesario desvelar, intentar atrapar en ese más allá informe que se abre cuando las palabras no alcanzan. Un libro de poesía debería pensarse como una invitación a transitar por lo desconocido, a dejarnos impregnar de aquello que nos es ajeno y nos confronta. Pero este libro, estas canales recorridas por palabras como lluvia o que se atascan como hojas secas que se convierten en madrigueras o esas cenizas como polvo arrastrado por las carreteras… estos poemas nos enfrentan a lo cotidiano. Aquí veremos la levedad de una vida: aquello que se nos escapa como espectadores de la muerte, que se nos convierte en perorata, en cháchara, en abandono existencial que, de a pocos, se refugia en las noticias, en los eventos deportivos vistos en televisión que, como parte del encierro, nos hacen pensar en un afuera, a veces promesa utópica, a veces crueldad descarnada. Un mundo de mensajes perdidos en autopistas informáticas que nos van llenando de ausencias hasta enfermarnos, hasta obligarnos a aceptar una soledad que no desaparece ni siquiera en las calles de las ciudades y su bullicio. Sin embargo, estas urbes nos enseñan sobre un miedo que se convierte en desprecio, que luego se convertirá en desapego. Un desapego que nos permitirá tomar una carretera, una línea de fuga que nos habrá dejado salir de nosotros mismos. Ediciones UCC quiere agradecer a Marco Cardona por permitirnos publicar sus poemas y presentar al público lo que sabemos es una obra emotiva y bella. Pero sobre todo, es una apuesta por una escritura honesta y dispuesta a tratar de descifrar lo que en lo rutinario de nuestras vidas queda escondido porque lo tomamos como sobreentendido.

The classical approach for calibrating non-ratiometric fluorescent Ca2+ dyes entails the measurement of the fluorescence maximum (Fmax) and minimum (Fmin), as well as the dissociation constant (Kd) of the Ca2+—Dye reaction (model 1). An alternative equation does not need the Fmin but requires the rate constants kon and koff (model 2). However, both approaches are experimentally time consuming and the rate constants for several dyes are unknown. Here, we propose a set of equations (model 3) that simplify the calibration of fluorescent Ca2+ transients obtained with non-ratiometric dyes. This equation allows the calibration of signals without using the Fmin: [Ca2+] = Kd(F − Frest/Fmax − F) + [Ca2+]IR(Fmax − Frest/Fmax − F), where [Ca2+]IR is the resting [Ca2+]. If the classical calibration approach is followed, the Fmin can be estimated from: Fmin = Frest − ([Ca2+]IR(Fmax − Frest)/Kd). We tested the models’ performance using signals obtained from enzymatically dissociated flexor digitorum brevis fibers of C57BL/6 mice loaded with Fluo-4, AM. Model 3 performed the same as model 2, and both gave peak [Ca2+] values 15 ± 0.3% (n = 3) lower than model 1, when we used our experimental Fmin (1.24 ± 0.11 A.U., n = 4). However, when we used the mathematically estimated Fmin (6.78 ± 0.2 A.U) for model 1, the peak [Ca2+] were similar for all three models. This suggests that the dye leakage makes a correct determination of the Fmin unlikely and induces errors in the estimation of [Ca2+]. In conclusion, we propose simpler and time-saving equations that help to reliably calibrate cytosolic Ca2+ transients obtained with non-ratiometric fluorescent dyes. The use of the estimated Fmin avoids the uncertainties associated with its experimental measurement.

Hummingbirds are perhaps the most exquisite bird species because of their prominent iridescence, created by stacks of melanosomes in the feather barbules. The feather colours crucially depend on the nanoscopic dimensions of the melanosome, and the displayed iridescence can distinctly vary, dependent on the spatial organization of the barbs and barbules. We have taken the genus Coeligena as a model group, with species having feathers that strongly vary in their spatial reflection properties. We studied the feather morphology and the optical characteristics. We found that the coloration of Coeligena hummingbirds depends on both the Venetian-blind-like arrangement of the barbules and the V-shaped, angular arrangement of the barbules at opposite sides of the barbs. Both the nanoscopic and microscopic organization of the hummingbird feather components determine the bird's macroscopic appearance.

The modelling of many complex systems is usually approached by directed networks where nodes and connections represent the elements of the system and their interactions respectively. The degree-assortativity, which is the tendency of nodes to link to nodes of similar degree, has four components in the digraphs case. In comparison with the undirected graph case, the degree-assortativity of digraphs has not been well studied despite the potential effects that it has to constraint or influence the structural and dynamical properties of a network. Thus, we have considered a random directed network and numerically trained the assortativity profiles of the four components (in–out; out–in; in–in; out–out) by applying degree-preserving rewiring, but we interestingly found that the widely used two-swap method is severely limited. In consequence, we used a much powerful and rather forgotten three-swap method capable to achieve all different assortativities configurations of the given initial random graphs. Secondly, we characterized the obtained networks in relation to other common structural properties such as path length and algebraic connectivity. Finally, by simulating and analysing a dynamical process on the network, we have found that certain profiles cause the network to exhibit enhanced sensitivity to small perturbations without losing their stability.

Background: Spiders are among the most venomous animals in nature. Their venom constitutes a source of novel and innovative peptides and proteins with medicinal and biotechnological interest. However, their potential as antimicrobial, anti-cancerous, anti-hypertensive and even in the modulation of nociception is under-studied, mainly because handling the venom is technically challenging and there is paucity of next-generation-sequencing (NGS) data. Due to the increasing evidence of underestimation of the number of genes by the use of a single transcriptome assembler, we re-assembled and optimized the de novo transcriptome of the venom gland of the recently described Colombian spider P. verdolaga, by using three free access algorithms: Trinity, Soapdenovo and SPAdes. All the assemblies were evaluated by statistical parameters (e.g. contigs, GC%, max and min length and N50), by applying BUSCO´s terms retrieval against the arthropod data set to determine the best assembly for each software.Results: Our analyses show that while approximately 54% of all the assembled and structurally annotated sequences could be found in all three algorithms, around 23% of these were unique for Trinity and 21% were unique for SPAdes. The non-redundant merge of all three assemblies’ output permitted the annotation of 8640 sequences; at least 15% more when compared to each software separately, and an increase of 20% when compared to a previous P. verdolaga assembly. Analysis of the annotated genes allowed the identification of unreported lectins, kinins and over 200 peptides and proteins with potential antimicrobial and protease inhibition activities. Furthermore, homology search against the Arachnoserver database and the EROP knowledgebase allowed the identification of 135 novel theraphotoxins of biotechnological interest.Conclusion: Transcriptomic data is of utmost importance for spiders, as it is one of the more feasible and scalable ways to characterize these organisms. However, the use of a single de novo assembler implies an under representation of the expressed sequences, as it has been shown here. In the generation of data for non-model organisms as well as in the search for novel peptides and proteins with biotechnological interest, it is highly recommended that at least two different assemblers are employed.

Biophysical characterization of antimicrobial peptides helps to understand the mechanistic aspects of their action. The physical behavior of the KR-12 antimicrobial peptide (e.g. orientation and changes in secondary structure), was analyzed after interactions with a Staphylococcus aureus membrane model and solid surfaces. We performed antimicrobial tests using Gram-positive S. aureus (ATCC 25923) bacteria. Moreover, Langmuir-Blodgett experiments showed that the synthetic peptide can disturb the lipidic membrane at a concentration lower than the Minimum Inhibitory Concentration, thus confirming that KR-12/lipid interactions are involved. Partially- and fully-deactivated KR-12 hybrid samples were obtained by physisorption and covalent immobilization in chitosan/silica and glyoxal-rich solid supports. The correlation of Langmuir-Blodgett data with the α-helix formation, followed by FTIR-ATR in a frozen-like state, and the antimicrobial activity showed the importance of these interactions and conformation changes on the first step action mode of this peptide. This is the first time that material science (immobilization in solid surfaces assisted by FTIR-ATR analysis in frozen-like state) and physical (Langmuir-Blodgett/Schaefer) approaches are combined for exploring mechanistic aspects of the primary action mode of the KR-12 antimicrobial peptide against S. aureus.

Among the many richly coloured birds, hummingbirds with their brilliant colouration are outstanding. We studied the plumage of male and female Blue-throated Starfrontlet,Coeligena helianthea, which exhibits a marked sexual dichromatism. The wide diversity of coloured feathers (blue, purple, golden, green, red) makes it an attractive species to investigate the structural basis of the colouration and to study the connection between the displayed colours and the perception by conspecifics. We analysed the optical properties of the feather barbules, applying spectrophotometry, scatterometry, and electron microscopy. Using the anatomical results, the spectral data can be interpreted by optical modelling. The reflectance spectra of the feathers of maleC. heliantheastrikingly overlap with the spectral sensitivities of bird photoreceptors, which suggests that the feather and photoreceptor spectra are tuned.

Background Mag-Fluo-4 is increasingly employed for studying Ca2+ signaling in skeletal muscle; however, the lack of information on the Ca2+-Mag-Fluo-4 reaction limits its wider usage. Methods Fluorescence and isothermal titration calorimetry (ITC) experiments were performed to determine the binding stoichiometry (n) and thermodynamics (enthalpy (ΔH) and entropy (ΔS) changes), as well as the in vitro and in situ Kd of the Ca2+-Mag-Fluo-4 reaction. Rate constants (kon, koff), fluorescence maximum (Fmax), minimum (Fmin), and the dye compartmentalization were also estimated. Experiments in cells used enzymatically dissociated flexor digitorum brevis fibres of C57BL6, adult mice, loaded at room temperature for 8 min, with 6 μM Mag-Fluo-4, AM, and permeabilized with saponin or ionomycin. All measurements were done at 20 °C. Results The in vitro fluorescence assays showed a binding stoichiometry of 0.5 for the Ca2+/Mag-Fluo-4 (n = 5) reaction. ITC results (n = 3) provided ΔH and ΔS values of 2.3 (0.7) kJ/mol and 97.8 (5.9) J/mol.K, respectively. The in situ Kd was 1.652 × 105μM2(n = 58 fibres, R2 = 0.99). With an Fmax of 150.9 (8.8) A.U. (n = 8), Fmin of 0.14 (0.1) A.U. (n = 10), and ΔF of Ca2+ transients of 8.4 (2.5) A.U. (n = 10), the sarcoplasmic [Ca2+]peak reached 22.5 (7.8) μM. Compartmentalized dye amounted to only 1.1 (0.7)% (n = 10). CONCLUSIONS: Two Mag-Fluo-4 molecules coalesce around one Ca2+ ion, in an entropy-driven, very low in situ affinity reaction, making it suitable to reliably track the kinetics of rapid muscle Ca2+ transients. General significance Our results may be relevant to the quantitative study of Ca2+ kinetics in many other cell types.

Morpho butterflies are universally admired for their iridescent blue coloration, which is due to nanostructured wing scales. We performed a comparative study on the coloration of 16 Morpho species, investigating the morphological, spectral and spatial scattering properties of the differently organized wing scales. In numerous previous studies, the bright blue Morpho coloration has been fully attributed to the multi-layered ridges of the cover scales' upper laminae, but we found that the lower laminae of the cover and ground scales play an important additional role, by acting as optical thin film reflectors. We conclude that Morpho coloration is a subtle combination of overlapping pigmented and/or unpigmented scales, multilayer systems, optical thin films and sometimes undulated scale surfaces. Based on the scales' architecture and their organization, five main groups can be distinguished within the genus Morpho, largely agreeing with the accepted phylogeny.

[EN] The genetic mechanisms underlying fruit development have been identified in Arabidopsis and have been comparatively studied in tomato as a representative of fleshy fruits. However, comparative expression and functional analyses on the bHLH genes downstream the genetic network, ALCATRAZ (ALC) and SPATULA (SPT), which are involved in the formation of the dehiscence zone in Arabidopsis, have not been functionally studied in the Solanaceae. Here, we perform detailed expression and functional studies of ALC/SPT homologs in Nicotiana obtusifolia with capsules, and in Capsicum annuum and Solanum lycopersicum with berries. In Solanaceae, ALC and SPT genes are expressed in leaves, and all floral organs, especially in petal margins, stamens and carpels; however, their expression changes during fruit maturation according to the fruit type. Functional analyses show that downregulation of ALC/SPT genes does not have an effect on gynoecium patterning; however, they have acquired opposite roles in petal expansion and have been co-opted in leaf pigmentation in Solanaceae. In addition, ALC/SPT genes repress lignification in time and space during fruit development in Solanaceae. Altogether, some roles of ALC and SPT genes are different between Brassicaceae and Solanaceae; while the paralogs have undergone some subfunctionalization in the former they are mostly redundant in the latter., This work was funded by COLCIENCIAS (111565842812), the iCOOP + 2016 COOPB20250 from the Centro Superior de Investigación Científica, CSIC, the ExpoSeed (H2020.MSCA-RISE-2015-691109) EU grant, the Convocatoria Programáticas 2017-16302, and the Estrategia de Sostenibilidad 2018-2019, from the Universidad de Antioquia. The authors would like to thank the group members of the Ferrándiz and Madueño Labs at IBMCP-UPV for training and help in the standardization of in situ hybridization. Finally, the authors thank Ricardo Callejas and Zulma Monsalve, from the Universidad de Antioquia, for their helpful suggestions during this research.

The male Anna's hummingbird features a brightly reddish-pink reflecting gorget, due to large stacks of melanosomes in the feather barbules, arranged in layers separated by keratin. Direct observations together with detailed scatterometry demonstrated that the barbules reflect incident light in an approximately specular manner. The structural colouration is iridescent, i.e. varies with a changing angle of light incidence. Spectrophotometrical measurements of the barbule reflectance and absorbance can be well interpreted with calculated spectra obtained with a transfer matrix method for optical multilayers, using anatomical data and measured refractive index spectra. The organization of the reflectors as a Venetian blind presumably functions to create a high spectral contrast of the male's plumage during courtship.

Butterflies belonging to the nymphalid subfamily, Morphinae, are famous for their brilliant blue wing coloration and iridescence. These striking optical phenomena are commonly explained as to originate from multilayer reflections by the ridges of the wing scales. Because the lower lamina of the scales of related nymphalid butterflies, the Nymphalinae, plays a dominant role in the wing coloration, by acting as a thin film reflector, we investigated single blue scales of three characteristic Morpho species: M. epistrophus, M. helenor and M. cypris. The experimental data obtained by spectrophotometry, scatterometry and scanning electron microscopy demonstrated that also in the Morpho genus the lower lamina of both the cover and ground scales acts as an optical thin film reflector, contributing importantly to the blue structural coloration of the wings. Melanin pigment has a contrast-enhancing function in a sub-class of ground scales. Electronic supplementary material The online version of this article (doi:10.1007/s00359-016-1084-1) contains supplementary material, which is available to authorized users.

The ABRI peptide is involved in the neurodegenerative disease Familial British Dementia, which has its origin in the misfolding of the peptide. Characterizing the most probable conformations of the monomer in solution can provide insights into how misfolding could occur in the steps prior to aggregation. Specifically, we analyzed the structural effects caused by the formation of a single disulfide bond, which has been reported to be important in amyloid assembly. We used all-atom molecular dynamics simulations with an enhanced sampling technique to obtain the lowest free energy conformations for two cases: the peptide with and without the disulfide bond between residues 5Cys and 22Cys. Bulk measurements on the conformations agree with experiments by elucidating ABRI as a disordered peptide. We find remarkable differences at the microscopic level between the most probable structures; with the disulfide bond the peptide is compact and α-helical, without the bond it is partially extended with slight β-bridges.

Background: Ultrastructures in butterfly wing scales can take many shapes, resulting in the often striking coloration of many butterflies due to interference of light. The plethora of coloration mechanisms is dazzling, but often only single mechanisms are described for specific animals.Results: We have here investigated the male Rajah Brooke's birdwing, Trogonoptera brookiana, a large butterfly from Malaysia, which is marked by striking, colorful wing patterns. The dorsal side is decorated with large, iridescent green patterning, while the ventral side of the wings is primarily brown-black with small white, blue and green patches on the hindwings. Dense arrays of red hairs, creating a distinct collar as well as contrasting areas ventrally around the thorax, enhance the butterfly's beauty. The remarkable coloration is realized by a diverse number of intricate and complicated nanostructures in the hairs as well as the wing scales. The red collar hairs contain a broad-band absorbing pigment as well as UV-reflecting multilayers resembling the photonic structures of Morpho butterflies; the white wing patches consist of scales with prominent thin film reflectors; the blue patches have scales with ridge multilayers and these scales also have centrally concentrated melanin. The green wing areas consist of strongly curved scales, which possess a uniquely arranged photonic structure consisting of multilayers and melanin baffles that produces highly directional reflections.Conclusion: Rajah Brooke's birdwing employs a variety of structural and pigmentary coloration mechanisms to achieve its stunning optical appearance. The intriguing usage of order and disorder in related photonic structures in the butterfly wing scales may inspire novel optical materials as well as investigations into the development of these nanostructures in vivo.

GM1 ganglioside is known to be involved in the amyloid-associated diseases and it is a crucial factor for the assembly of amyloid proteins on lipid-rafts, which are lipid structures located on the synaptic plasma membranes. Due to its slow aggregation rate, we employed salmon calcitonin (sCT) as a suitable probe representative of amyloid proteins, to study the interaction between this class of proteins and a membrane model. Here, we prepared a neuronal membrane model by depositing onto mica two Langmuir-Blodgett films in liquid-condensed phase: the outer monolayer was characterized by high content of GM1 (50%) and minority parts of cholesterol and POPC (25–25%), while the inner one by plain POPC. To deeply investigate the interaction of sCT with this model and the role-played by GM1, we prepared the outer leaflet adding sCT at a concentration such that the number of proteins equals that of GM1. Atomic Force Microscopy revealed the occurrence of two distinct kinds of flat surfaces, with globular aggregates localized exclusively on top of the highest one. To unravel the nature of the interaction, we studied by ζ-potential technique liposomes composed as the outer leaflet of the model. Results demonstrated that an electrostatic interaction sCT-GM1 occurred. Finally, to investigate the interaction thermodynamics between sCT and the outer leaflet, Langmuir films as the outer monolayer and containing increasing content of sCT were studied by compression isotherms and Brewster Angle Microscopy experiments. Based on the all body of results we propose an interaction model where GM1 plays a pivotal role., Highlights • Membrane models mimicking the occurrence of lipid-rafts and sCT, were investigated. • Atomic Force Microscopy shows sCT globular aggregates onto very flat surfaces. • ξ-potential data indicate that electrostatic interaction occurs between sCT and GM1. • Thermodynamic data of the outer leaflet reveal that sCT aggregate outside the film. • GM1, one component of the lipid-rafts, result to trigger the interaction.

Depending on the species, the individual scales of butterfly wings have a longitudinal gradient in structure and reflectance properties, as shown by scanning electron microscopy and microspectrophotometry. White scales of the male Small White, Pieris rapae crucivora, show a strong gradient in both the density in pigment granules and the reflectance. After pigment extraction by aqueous ammonia, scales of male P. r. crucivora closely resemble the unpigmented scales of female P. r. crucivora. Only a minor gradient exists in the white and orange scales of the male Orange Tip, Anthocharis cardamines. Pigment extraction of orange scales of A. cardamines causes bleaching. Partial bleaching transforms the scales so that they resemble certain scales of Phoebis philea that have a natural extreme gradient. Reflectance measurements on an artificial stack of two overlapping scales as well as on the scale stacks existing on intact and partially denuded wings of the Large White, Pieris brassicae, quantitatively demonstrate the reflectance enhancement by scale stacking. (C) 2007 Elsevier Ltd. All rights reserved.

RESUMEN: Se aplica la teoría del color propuesta por Heavens (1991) para el cálculo de los espesores de las películas delgadas de magnetita, Fe3 O4 , los cuales fueron obtenidos por tratamiento térmico a 250°C de una aleación de oro (Au-24.5Fe-0.5Co). Los espectros de reflectancia obtenidos de las muestras pulidas con diferentes grados de oxidación (y de color) fueron usados para calcular los índices de refracción (real) y de extinción (imaginario) del sustrato metálico (n2 , k2 ) y de la capa de magnetita (n1 =2,42, k1 ). La forma a+bλ+cλ2 se tomó del ajuste de parámetros entre las curvas experimentales y teóricas. El ajuste de los datos resultan en desviaciones entre 2 y 10%, para los espesores en el rango de 0 nm (solo metal original) y 65 nm (color azul oscuro). Por medio de un modelo matemático siguiendo la teoría de Heavens, el espesor de cada capa ha sido predicho con alta precisión, utilizando las mediciones de reflectancia espectral. En consecuencia, proponemos que mediante el uso de esta metodología se pueden obtener fácilmente los valores de los coeficientes de extinción de las especies de óxido y, además, se pueden predecir los espesores de la capa de óxido. Los valores de espesores de la magnetita encontrados en la presente investigación están dentro del intervalo reportado en la literatura para la interferencia de primer orden en los aceros, desde el amarillo claro (~46 nm) hasta el azul (~72 nm). ABSTRACT: The colour theory proposed by Heavens in 1991 has been applied to calculate the thickness of magnetite thin layers, Fe3 O4 , which were obtained by heat treatment at 250 °C in a gold alloy (Au-24.5Fe-0.5Co). The reflectance spectra obtained from the polished samples with different oxidation (and colour) degrees were used to calculate the real part of the refraction index and the (imaginary) extinction coefficients of both the metallic substrate (n2 , k2 ) and the magnetite layer (n1 =2.42, k1 ). The a+bλ+cλ2 form was taken adjusting parameters between experimental and theoretical curves. The fitting of the data resulted in deviations between 2 and 10% for thicknesses in the range of 0 nm (only substrate) and 65 nm (dark blue colour). By means of a mathematic model and following the Heavens’ theory, the thickness of each layer has been predicted with high precision, using the spectral reflectance. Consequently, we propose that by using this methodology, the values of the extinction coefficients of the oxide species can be easily obtained, and the thicknesses of the oxide layers can be predicted. The magnetite thickness values found in this study fall into the interval reported in the literature for first-order interference in steels, from light-yellow (~46 nm) to blue (~72 nm).

The colors of butterfly wings are determined by the structural as well as pigmentary properties of the wing scales. Reflectance spectra of the wings of a number of pierid butterfly species, specifically the small white, Pieris rapae, show that the long-wavelength reflectance of the scales in situ, on the wing, is distinctly higher than that of single, isolated scales. An optical model explains that this is due to multiple scattering on overlapping scales by treating the layers of scales on both sides of the wing as a stack of incoherently scattering plates. The model sheds new light on the adaptive significance and evolution of butterfly wing patterns. (c) 2006 Optical Society of America.

In this study, Intermediate Body Positions refers to a group of spontaneous gestures assumed by people interacting with surrounding objects, which are in between biped-erect and sitting-standard. Furniture that motivates the sitting-standard posture is usually found in outdoors as the only option to rest; therefore users adopt different objects to rest their body. In this study, we observed the common postures adopted in public spaces while spontaneously using objects which were not designed to rest the body. The study conducted the evaluation of three Intermediate Body Positions and two control postures (sitting and standing) with two different finishing surfaces (rough and smooth), and the registration of the angles and forces in the points of support with a Dinagoniometer. The posture’s performance was evaluated in terms of time of permanence, energy expenditure and subjective perceived exertion measured in five male models in laboratory conditions. These results were compared with the angles and forces measured at each point of support. We have found that the interaction of the body with different types of materials and at different positions is crucial, since they specify not only the biophysical reaction of the body, but the individual perception. These results permitted to establish a number of design principles for furniture and public spaces.

Histone acetyltransferase activity by transcriptional cofactors such as CREB-binding protein (CBP) and post-translational modifications by small ubiquitin-like modifier-1 (SUMO-1) have shown to be relevant for synaptic and neuronal activity. Here, we investigate whether SUMOylation of CBP plays a role in spatial learning. We assessed protein levels of CBP/p300, SUMO-1, and CBP SUMOylation in the hippocampi of rats trained on the Morris water maze task. Furthermore, we evaluated the post-translational modifications at Zif268, BDNF, and Arc/Arg3.1 promoters using chromatin immunoprecipitation with anti-Acetyl-Histone H3-Lys14 (H3K14Ac) and SUMO-1. We found that CBP/p300 protein expression is unchanged in animals trained for 7 days. However, H3K14Ac-specific histone acetyltransferase activity showed specific hyperacetylation at promoters of Zif268 and BDNF-pI but not of Arc/Arg3.1 and BDNF-pIV. In naive animals, CBP is selectively SUMOylated and the Arc/Arg3.1 promoter is differentially occupied by SUMO-1, although SUMO-1 levels are unchanged. These results suggest a specific negative regulation by SUMO-1 on CBP function and its effect on epigenetic changes triggered by spatial learning and memory processes.

SUMMARY The wings of the swordtail butterfly Graphium sarpedon nipponum contain the bile pigment sarpedobilin, which causes blue/green colored wing patches. Locally the bile pigment is combined with the strongly blue-absorbing carotenoid lutein, resulting in green wing patches and thus improving camouflage. In the dorsal forewings, the colored patches lack the usual wing scales, but instead have bristles. We have found that on the ventral side most of these patches have very transparent scales that enhance, by reflection, the wing coloration when illuminated from the dorsal side. These glass scales furthermore create a strongly polarized iridescence when illuminated by obliquely incident light from the ventral side, presumably for intraspecific signaling. A few ventral forewing patches have diffusely scattering, white scales that also enhance the blue/green wing coloration when observed from the dorsal side.

The beads in the wing scales of pierid butterflies play a crucially important role in wing coloration as shown by spectrophotometry and scanning electron microscopy (SEM). The beads contain pterin pigments, which in Pieris rapae absorb predominantly in the ultraviolet (UV). SEM demonstrates that in the European subspecies Pieris rapae rapae , both males and females have dorsal wing scales with a high concentration of beads. In the Japanese subspecies Pieris rapae crucivora , however, only the males have dorsal wing scales studded with beads, and the dorsal scales of females lack beads. Microspectrophotometry of single scales without beads yields reflectance spectra that increase slightly and monotonically with wavelength. With beads, the reflectance is strongly reduced in the UV and enhanced at the longer wavelengths. By stacking several layers of beaded scales, pierid butterflies achieve strong colour contrasts, which are not realized in the dorsal wings of female P. r. crucivora . Consequently, P. r. crucivora exhibits a strong sexual dichroism that is absent in P. r. rapae .

The angular and spectral reflectance of single scales of five different butterfly species was measured and related to the scale anatomy. The scales of the pierids Pieris rapae and Delias nigrina scatter white light randomly, in close agreement with Lambert's cosine law, which can be well understood from the randomly organized beads on the scale crossribs. The reflectance of the iridescent blue scales of Morpho aega is determined by multilayer structures in the scale ridges, causing diffraction in approximately a plane. The purple scales in the dorsal wing tips of the male Colotis regina act similarly as the Morpho scale in the blue, due to multilayers in the ridges, but the scattering in the red occurs as in the Pieris scale, because the scales contain beads with pigment that does not absorb in the red wavelength range. The green-yellow scales of Urania fulgens backscatter light in a narrow spatial angle, because of a multilayer structure in the scale body.

Since there are uncertainties about the concentration of free cytosolic Ca2+ reached in a muscle fiber during a transient elicited by electric stimulation, and about the KdCa2+ of the fast dye Magfluo-4, we performed two groups of experiments aimed at calibrating the Ca2+ transients obtained with this dye. For the fiber experiments, we used murine single skeletal muscle fibers obtained from enzymatically dissociated flexor digitorum brevis, loaded with 8-10 μM of the dye in its acetoxymethyl ester form, during 40 min at 21-22°C, to determine Fmax, Fmin and dye compartmentalization. The cells were permeabilized with saponine and exposed to 50 mM of free calcium to intracellularly saturate the dye. Compartmentalization was assessed using digitonin and triton-X100. For our conditions, Fmax and Fmin were 160±14 (n=9, mean±SEM) and 3.4±0.7 (n=6). Dye compartmentalization was found to be less than 10% (n=1). For the in vitro experiments, KdCa2+ (20°C) values of 21.6 μM, 27.8 μM and 29.1 μM were obtained in presence of 0, 1 and 2 mM free Mg2+, respectively. To calculate Ca2+ concentration from the fluorescence signals, we used the methodologies proposed by Grynkiewicz et al. (1985) and by Caputo et al. (1994). Preliminary results, taking into account our data or some values from the literature (Baylor et al. 2009), show single Ca2+ transient's peak between 2 and 7 μM (n=4). We are now calculating the kinetics of Ca2+ transients and the quantitative changes induced by modulating Ca2+ release and sequestration mechanisms in different fiber types. In conclusion, we have calculated the peak Ca2+ concentration after single stimulation in fibers loaded with Magfluo-4. Our preliminary results are comparable to those obtained with other fast Ca2+ dyes, such as Magfura-5, but lower than those reported with Magfura-2.