The Myth of The Annular Lipids

In the early 1970s, the existence of a “lipid annulus” stably surrounding the individual intrinsic protein molecules was proposed by several authors. They referred to a number of lipid molecules in slow exchange with the bulk lipid in the bilayer, i.e., more or less protein-bound, and more ordered than the bulk lipid. The annular lipids would control enzyme activity. This idea was uncritically accepted by most scientists working with intrinsic membrane proteins at the time, so that the idea operated like a myth in the field. However, in the following decade, hard spectroscopic and biochemical evidence showed that the proposed annular lipids were not immobilized for a sufficiently long time to influence enzyme or transporter activity, nor were they ordered by the protein. Surprisingly, forty years later, the myth survives, and the term ‘annular lipid’ is still in use, in a different, but even more illogical sense.This research was funded in part by the Spanish Ministerio de Ciencia e Innovación (MCI), Agencia Estatal de Investigación (AEI) and Fondo Europeo de Desarrollo Regional (FEDER) (grant No. PID2021-124461NB-I00), by the Basque Government (grant No. IT1625-22), by Fundación Ramón Areces (CIVP20A6619), by Fundación Biofísica Bizkaia, and by the Basque Excellence Research Centre (BERC) program of the Basque Government

Effects of gelatin origin, bovine-hide and tuna-skin, on the properties of compound gelatin-chitosan films

With the purpose to improve the physico-chemical performance of plain gelatin and chitosan films, compound gelatin-chitosan films were prepared. The effect of the gelatin origin (commercial bovine-hide gelatin and laboratory-made tuna-skin gelatin) on the physico-chemical properties of films was studied. The dynamic viscoelastic properties (elastic modulus G', viscous modulus, G″ and phase angle) of the film-forming solutions upon cooling and subsequent heating revealed that the interactions between gelatin and chitosan were stronger in the blends made with tuna-skin gelatin than in the blends made with bovine-hide gelatin. As a result, the fish gelatin-chitosan films were more water resistant (∼18% water solubility for tuna vs 30% for bovine) and more deformable (∼68% breaking deformation for tuna vs 11% for bovine) than the bovine gelatin-chitosan films. The breaking strength of gelatin-chitosan films, whatever the gelatin origin, was higher than that of plain gelatin films. Bovine gelatin-chitosan films showed a significant lower water vapour permeability (WVP) than the corresponding plain films, whereas tuna gelatin-chitosan ones were only significantly less permeable than plain chitosan film. Complex gelatin-chitosan films behaved at room temperature as rubbery semicrystalline materials. In spite of gelatin-chitosan interactions, all the chitosan-containing films exhibited antimicrobial activity against Staphylococcus aureus, a relevant food poisoning. Mixing gelatin and chitosan may be a means to improve the physico-chemical performance of gelatin and chitosan plain films, especially when using fish gelatin, without altering the antimicrobial properties. © 2011 Elsevier Ltd.Peer Reviewe

A Poglut1 mutation causes a muscular dystrophy with reduced Notch signaling and satellite cell loss

Skeletal muscle regeneration by muscle satellite cells is a physiological mechanism activated upon muscle damage and regulated by Notch signaling. In a family with autosomal recessive limbgirdle muscular dystrophy, we identified a missense mutation in POGLUT1 (protein O-glucosyltransferase 1), an enzyme involved in Notch posttranslational modification and function. In vitro and in vivo experiments demonstrated that the mutation reduces Oglucosyltransferase activity on Notch and impairs muscle development. Muscles from patients revealed decreased Notch signaling, dramatic reduction in satellite cell pool and a muscle-specific adystroglycan hypoglycosylation not present in patients’ fibroblasts. Primary myoblasts from patients showed slow proliferation, facilitated differentiation, and a decreased pool of quiescent PAX7+ cells. A robust rescue of the myogenesis was demonstrated by increasing Notch signaling. None of these alterations were found in muscles from secondary dystroglycanopathy patients. These data suggest that a key pathomechanism for this novel form of muscular dystrophy is Notch-dependent loss of satellite cells.Junta de Andalucía PI-0017-201

Levantamientos topográficos en la III Campaña de Excavaciones en Tell Mahuz - Iraq I

In the third campaign of the archaeological excavations performed in Tell Mahuz (September-October 2000), a group of Surveying engineers has taken part, whose aim has been the mapping of Tell and its environment. The surface to be represented exceeds 100 hectares. This article highlights the peculiarities to take into account when mapping an archaeological site, and it describes the fieldwork carried out during the campain

Capsaicin affects the structure and phase organization of phospholipid membranes

AbstractCapsaicin is a natural compound with pharmacological and toxicological effects, which given its hydrophobicity, can influence the structure of membranes. The interaction of capsaicin with model membranes of dipalmitoylphosphatidylcholine and dielaidoylphosphatidylethanolamine has been studied by using differential scanning calorimetry, fluorescent probe spectroscopy and 31P-nuclear magnetic resonance. Capsaicin remarkably affects the phase transition of dipalmitoylphosphatidylcholine, shifting the transition temperature to lower values, and giving rise, at relatively high capsaicin concentrations, to the appearance of two peaks in the thermogram. These peaks may correspond to separated phases as indicated by the partial phase diagram. Whereas capsaicin did not affect the fluorescence polarization of the probes diphenylhexatriene and trimethylammonium-diphenylhexatriene, it clearly affected that of the probe 2-anthroyloxystearic acid, indicating that the perturbation produced by capsaicin on the membrane would be mainly at the position where this fluorophore is located. On the other hand, capsaicin, at relatively low concentrations, gives rise to immiscible phases in the presence of dielaidoylphoshatidylethanolamine and decrease the temperature of the lamellar to hexagonal HII phase transition. At concentrations of capsaicin higher than 0.3 mol fraction, isotropic phases were detected. The possible implications of the effects of capsaicin on biological membranes are discussed

Estudio de la anteversión femoral

Se estudian los valores angulares de la anteversión femoral en 30 fémures humanos secos normales, del lado izquierdo y pertenecientes a individuos adultos. Los valores angulares de la muestra son sometidos a estudio estadístico dando una fiabilidad de la media para p = 0,01 . Se revisa la bibliografía de otras mediciones realizadas en hueso seco y se comparan con los valores obtenidos en este trabajo. Los valores obtenidos contribuirán a un mejor conocimiento del ángulo de anteversión femoral y consecuentemente a la aplicación clínica del mismo

Los edificios de paneles más altos de España

RESUMEN Este artículo describe el proceso constructivo de un conjunto de 484 viviendas realizadas con paneles prefabricados portantes de hormigón. Dicho conjunto edi¿catorio, de 20 plantas de altura, se compone de diversos bloques que integran además, locales comerciales, o¿cinas, trasteros, 4 plantas de garaje e instalaciones comunes. El principal interés de este edi¿cio consiste en haber alcanzado veinte plantas sobre rasante y 4 más de sótano con el sistema constructivo de paneles prefabricados de hormigón INDAGSA; el cual dispone de un Documento de Idoneidad Técnica emitido por el IETcc, con el número DIT 452. Las obras de INDAGSA son conocidas por ser precisas, ordenadas y limpias; debido a estas características, se pudieron establecer visitas no sólo para doctorandos de la ETSAM, sino para estudiantes de la Cátedra de sistemas industrializados y prefabricados. A través de la descripción del sistema constructivo, podremos mostrar una perspectiva global de las posibilidades de los sistemas de paneles prefabricados de hormigón y las capacidades evolutivas de éstos

Roper Excitation in Alpha-Proton Scattering

We study the Roper excitation in the $(\alpha,\alpha')$ reaction. We consider all processes which may be relevant in the Roper excitation region, namely, Roper excitation in the target, Roper excitation in the projectile, and double $\Delta$ excitation processes. The theoretical investigation shows that the Roper excitation in the proton target mediated by an isoscalar exchange is the dominant mechanism in the process. We determine an effective isoscalar interaction by means of which the experimental cross section is well reproduced. This should be useful to make predictions in related reactions and is a first step to construct eventually a microscopic $NN \rightarrow NN^*$ transition potential, for which the present reaction does not offer enough information.Comment: Latex 17 pages; figures available by request; Phys. Rev. C in prin

Influencia de algunas variables en el ensayo a compresión de probetas testigo en un hormigón autocompactante

La estimación de la resistencia a compresión a través de la evaluación de probetas testigo depende de numerosas variables, entre ellas, el diámetro de la probeta testigo, la dirección de extracción en relación con la dirección del hormigonado, el estado de humedad de la probeta testigo en el momento de ser ensayada, la esbeltez de la probeta testigo, la armadura embebida en la probeta testigo y la edad del hormigón investigado. El objetivo de este trabajo experimental ha sido evaluar, para un hormigón autocompactante, el efecto que presentan algunas de estas variables en el resultado de la resistencia a compresión de las probetas testigo. Estos efectos pueden ser muy diferentes de los que ocurren en el hormigón vibrado, debido a que no existe en este caso un procedimiento específico para la compactación de las probetas moldeadas. Igualmente se han analizado los posibles factores de corrección utilizados en la estimación de la resistencia a compresión de la probeta moldeada a través de la resistencia a compresión de la probeta testigo. Para ello se han fabricado 30 bloques de 50x50x100 cm en HAC cubriendo un amplio rango de resistencias (20 MPa - 80 MPa), de los cuales se extrajeron un total de 360 probetas testigo. Paralelamente a la ejecución de los bloques se han fabricado 90 probetas cilíndricas de 15 30 cm que posteriormente fueron ensayadas a compresión a la misma edad que las probetas testigo (28 días). Los resultados muestran que algunas de las variables incíden de forma muy diferente en estos hormigones que en los hormigones convencionales, en especial la dirección de extracción y el coeficiente de paso para considerar la resistencia en probeta moldeada