Myocardial trabeculation in embryos of Scyliorhinus canicula (Elasmobranchii, Chondrichthyans)

Currently, three types of ventricular myoarchitecture are recognized in vertebrates, namely compact, spongy (trabeculated) and mixed myocardium. Mixed myocardium, which has been recently proposed as the primitive condition in gnathostomes, is composed of two myocardial layers: an inner trabeculated and an outer compact one. The trabeculation process has been studied in teleosts, showing exclusively spongy myocardium, and mammals and birds, characterized by a compact myocardial ventricular wall. In zebrafish, mouse and chicken embryos, the trabeculae develop as luminal myocardial ridges protruding into the lumen. In mammals and birds, further compactation of trabeculae leads to the formation of a compact layer. The potential mechanisms that may contribute to the formation of the ridges are under discussion and include myocardial proliferation, endocardial invagination, and bending of the entire myocardial layer. However, no description of the development of the mixed myocardium is available. To shed some light on this issue, we have studied the heart development of an elasmobranch species with mixed myocardium, the lesser spotted dogfish (Scyliorhinus canicula; Chondrichthyes), by means of histological and immunohistochemical techniques for light microscopy, semithin sections, scanning electron microscopy and transmission electron microscopy. Our results suggest that in the dogfish the intertrabecular spaces develop by connections between early intramyocardial spaces and the lumen of the ventricle through invaginations of the endocardial line. Chondrichthyans are the earliest diverged lineage of gnathostomes and, consequently, they have the most primitive cardiac design. Although chicken, mouse, and recently zebrafish have been considered powerful vertebrate models to study heart development, we propose that the trabeculation process in the dogfish is representative of the early steps of the ventricular morphogenesis in vertebrates.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.Study supported by grant CGL2017-85090-P and CGL2014-52356-P (Ministerio de Economía y Competitividad), FPU15/03209 (Ministerio de Educación, Cultura y Deporte), FEDER, and Universidad de Málaga

MYOCARDIAL STRUCTURE AND VASCULARIZATION OF THE HEART VENTRICLE IN HOLOCEPHALI: IMPLICATIONS FOR HEART EVOLUTION

El resumen aparece en el Program & Abstracts of the 10th International Congress of Vertebrate Morphology, Barcelona 2013. Anatomical Record, Volume 296, Special Feature — 1: P-075.It has been classically assumed that the ventricle of the primitive vertebrate heart is composed of spongy myocardium, supplied exclusively by oxygen-poor, luminal blood. This idea is on two facts: (1) extant agnathans have a spongy ventricular myocardium, and (2) in avian and mammalian embryos, the formation of trabeculated myocardium precedes the appearance of compact myocardium. Recently, it has been proposed that, like elasmobranchs, the early gnathostomes possess a fully vascularised ventricle composed of mixed myocardium. We tested this idea by studying the structure and vascularisation of the ventricular myocardium in four holocephalan species of the families Chimaeridae and Rhinochimaeridae. Chimaera monstrosa, Hidrolagus affinis and Harriotta raleighana have a spongy myocardium covered by a thin layer of cardiac muscle. In H. raleighana, the compacta is reduced to an extremely fine rim. In all three species there is a well-developed coronary artery system consisting of subepicardial vessels which give off branches that penetrate the myocardial trabeculae. Rhinochimaera atlantica has no compacta and its ventricular coronary artery system is reduced to subepicardial vessels that do not enter the spongy layer. This report is the first to show that in wild living vertebrates, a coronary artery system supplying the whole myocardium exists in the absence of a well-developed compacta, which supports experimental work that shows that myocardial cell proliferation and coronary vascular growth rely on genetically separated programs. We conclude that the mixed ventricular myocardium is primitive for chondrichthyans, and that the lack of compacta in some holocephalans is a derived character. Moreover our results support the hypotheses that the mixed myocardium is the primitive condition in gnathostomes, and that the absence of a compacta in different actinopterygian taxa is the result of its repeated loss during evolution.Proyecto CGL2010-16417/BOS; Fondos FEDE

The Myosin Heavy Chain specific A4.1025 antibody discriminates different cardiac segments in ancient groups of gnathostomes: Morphological and evolutionary implications

El resumen aparece en el Program & Abstracts of the 11th International Congress of Vertebrate Morphology, Washington DC 2016. Anatomical Record, Volume 299, Special Feature: 263.The pan-Myosin Heavy Chain (pan-MyHC) marker MF20 have been reported to show similar, homogeneous signal in the myocardial segments of the heart of teleosts and tetrapods. However, in an ongoing study of the myocardial structure of the dogfish (Scyliorhinus canicula; Chondrichthyes), we observed differential immunostaining of the cardiac segments using another pan-MyHC, the A4.1025 antibody. In order to investigate the relevance of this finding for better understanding of the morphology and evolution of the vertebrate heart, we performed immunohistochemistry, slot blot and western blot in several species of chondrichthyans, actinopterygians and mammals using the above mentioned antibodies. In the dogfish heart, A4.1025 and MF20 specifically recognized MyHC isoforms, although with different degree of affinity. MF20 reactivity was homogeneous and high in all the myocardial segments. However, A4.1025 reactivity was heterogeneous. It was high in the sinus venosus (external layer), atrium and atrioventricular region, low in the ventricle and conus arteriosus, and null in the internal layer of the sinus venosus. A heterogeneous pattern of A4.1025 immunoreactivity was also detected in two other elasmobranchs, a holocephalan, a polypteryform and an acipenseriform. In all of these species, MF20 immunoreactivity was homogeneous. In addition, both markers showed a homogeneous immunoreactivity pattern in teleosts and mammals. Our results indicate that in the hearts of ancient gnathostomes, in all of which a conspicuous conus arteriosus exists, one or more MyHC isoforms with low affinity for A4.1025 show segment-specific distributions. Thus, A4.1025 appears to be an appropriated marker to identify the cardiac segments and their boundaries. We propose that the segmentspecific distribution of MyHC isoforms may generate a particular type of myocardial contractility associated with the presence of a conus arteriosus.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. CGL2014-52356-P, CEIMAR, BIO 203, FEDE

Consumer innovative behavior in vacation travel

This paper focuses on the study of innovative behavior of tourists through the dimensions of sensation seeking. To our knowledge, few studies have explored the dimensions of sensation seeking in relation to the innovative behavior of tourists in their holiday travel decisions. Sensation seeking is defined as the desire for varied, new, and complex experiences, and the willingness to take physical, social, legal, and financial risks in order to achieve such experience. Four components of sensation seeking are identified: thrill and adventure seeking; experience seeking; disinhibition; and boredom susceptibility. This study is based on a sample of 543 university students. The results show that innovators obtain higher scores on the total scale of sensation seeking than non-innovators, both men and women, as well as on the four dimensions of the scale. In addition, sensation seeking is a significant predictor of the consumer innovativeness in the vacation travel. It is noted that three of the four dimensions of sensation seeking (thrill and adventure seeking, experience seeking, and disinhibition) have a significant influence on the travel service innovativeness

Anatomical, histochemical and immunohistochemical characterization of the outflow tract of ray hearts (Rajiformes; Chondrichthyes)

El resumen aparece en el Program & Abstracts of the 11th International Congress of Vertebrate Morphology, Washington DC 2016. Anatomical Record, Volume 299, Special Feature: 264.Recent work has shown that the cardiac outflow tract of sharks and chimaeras does not consist of a single myocardial component, the conus arteriosus, as classically accepted, but two, namely, the myocardial conus arteriosus and the non-myocardial bulbus arteriosus. However, the anatomical composition of the outflow tract of the batoid hearts remains unknown. The present study was designed to fill this gap. The material examined consisted of hearts of two species of rays, namely, the Mediterranean starry ray (Raja asterias) and sandy ray (Leucoraja circularis). They were studied using scanning electron microscopy, and histochemical and inmunohistochemical techniques. In both species, the outflow tract consists of two components, proximal and distal with regard to the ventricle. The proximal component is the conus arteriosus; it is characterized by the presence of compact myocardium in its wall and several transverse rows of pocket-shaped valves at its luminal side. Each valve consists of a leaflet and its supporting sinus. Histologically, the leaflet has two fibrosas, inner and outer, and a middle coat, the spongiosa. The distal component lacks myocardium. Its wall consists of smooth muscle cells, elastic fibers and collagen. Thus, it shows an arterial-like structure. However, it differs from the aorta because it is covered by the epicardium and crossed by coronary arteries. These findings indicate that the distal component is morphologically equivalent to the bulbus arteriosus of sharks and chimaeras. In contrast to foregoing descriptions, the valves of the first transverse row are distally anchored to the bulbus arteriosus and not to the ventral aorta. Our findings give added support to the notion that presence of a bulbus arteriosus at the arterial pole of the heart is common to all chondrichtyans, and not an apomorphy of actinopterygians as classically thought.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. CGL2014-52356-P, CEIMAR, BIO 203, FEDE

Different laboratory mouse strains show distinct coronary artery patterns

Different laboratory mouse strains show distinct coronary artery patterns. MC Fernández 1,2, A López-García 1,2, M Lorenzale 1, V Sans-Coma 1,2, AC Durán 1,2 and B Fernández 1,2. 1 Department of Animal Biology, Faculty of Science, University of Málaga, Spain. 2 Biomedical Research Institute of Málaga (IBIMA), University of Málaga, Spain. The C57BL/6 (BL/6) mouse strain is one of the most common models in research involving laboratory animals, particularly on studies of the cardiovascular system. It has been reported (Fernandez B, et al. J Anat 2008 212(1):12–18) that this strain presents an unusual coronary artery (CA) pattern, including congenital CA anomalies, which are clinically relevant in humans. The aim of the present study was to elucidate whether this pattern is strain-specific or appears in other mouse populations. We used stereomicroscopy, scanning electron microscopy, light microscopy, and a corrosion cast technique in 597 adult mice belonging to three inbred strains (BL/6, Balb/c, DBA/2), three outbred stocks (CD1, OF1, NMR1), two hybrid lines (129sv x BL/6, CD2F1) and wild mice. Lock-like ostium was only detected in BL/6 mice, whereas left septal artery, accessory ostium, high take-off, intramural course, and solitary ostium of one CA in aorta were present in different laboratory strains and in wild mice. However, each mouse population showed a specific incidence of these coronary conditions. These results should be taken into account when studying the murine coronary system, especially in CA occlusion experiments and in studies on cardiovascular development involving murine mutant lines. In addition, we propose that several laboratory mouse strains may serve as appropriate animal models to study several clinically relevant human congenital anomalies of the CAs. Our results suggest that some of these CA anomalies are subject to a simple mode of inheritance. This work was supported by P10-CTS-6068 and PI- 0888-2012.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. P10-CTS-6068. PI-0888-201

Chamber specific expression of Myosin heavy chain 7b in the heart of vertebrates

In extant vertebrates, myosin heavy chain (MyHC) 6 and 7 are the main isoforms of atrial and ventricular myocardium respectively, whereas MyHC7b has been proposed to be an ancient cardiac isoform only expressed during embryonic development in modern species. In preliminary immunohistochemical studies of the heart of the lesser spotted dogfish (Scyliorhinus canicula; Chondrichthyes), we have observed that while MF20 labels homogeneously all the myocardium, A4.1025 labels the inflow cardiac segments (sinus venosus and atrium) but not the outflow segments (ventricle and conus arteriosus). In order to interpret these results, we have performed western and slot blots from samples of dogfish and hamster (Mesocricetus auratus) hearts, HPLC-ESI-MS/MS from dogfish samples, and immunohistochemistry in hearts of representative species of vertebrates, namely elasmobranchs, polypteriforms, acipenseriforms, teleosts and mammals, using MF20 and A4.1025 antibodies. Western and slot blot results confirmed the specificity of MF20 and A4.1025 for MyHC in dogfish, as well as their differential reactivity against different myocardial segments. HPLC-ESI-MS/MS using protein databases from Callorhinchus milii (Chondrichthyes) and Chordata revealed the presence of MyHC6 and 7 in all the dogfish myocardial segments, and of MyHC7b only in the outflow segments. Immunohistochemistry showed that while MF20 signals were homogeneous in all the myocardial segments of all the species studied, A4.1025 signals were restricted to the inflow myocardial segments in elasmobranchs, homogeneous in teleosts and acipenseriforms, and low in the ventricle of polypteriforms. It can be inferred that the A4.1025 antibody, as opposed to MF20, has a low affinity for MyHC7b, at least in the dogfish. In addition, we show that MyHC distribution in the cardiac chambers has changed during the evolution of gnathostomes.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.Study supported by grants CGL2017-85090-P and CGL2014-52356-P (Ministerio de Economía y Competitividad), FPU15/03209 (Ministerio de Educación, Cultura y Deporte), contract UMAJI75 (Junta de Andalucía, European Social Found), FEDER and Universidad de Málaga

Effect of hyperlipidic diets on normal and abnormal aortic valves in the Syrian hamster: A preliminary study

Effect of hyperlipidic diets on normal and abnormal aortic valves in the Syrian hamster: A preliminary study. MC Fernández 1,2, J Moncayo-Arlandi 1, MT Soto 1, MA López-Unzu 1, B Fernández 1,2 and AC Durán 1,2. 1 Department of Animal Biology, Faculty of Science, University of Málaga, Spain. 2 Biomedical Research Institute of Málaga (IBIMA), University of Málaga, Spain. Bicuspid aortic valve (BAV) is the most frequent human congenital cardiac malformation. It frequently becomes stenotic due to calcification by an atherosclerosis-like process. Hyperlipidic diets have been classically used to induce atherosclerosis in laboratory animals, including Syrian hamsters. The aim here is to evaluate the effect of hyperlipidic diets in hamsters having different incidence of BAVs. We used a unique inbred strain of Syrian hamsters with a high ( 40%) incidence of spontaneous BAV, morphologically similar to that in man, another inbred strain with a low ( 4%) incidence of BAV, and an outbred, second control line, acquired from Charles River Laboratories. Three experimental groups were fed with standard diet supplemented with 2% cholesterol plus 15% butter during five months. In parallel, three control groups were fed with unmodified standard diet. Hyperlipidic diets induced lesions in the aortic valve and ascending aortic wall, i.e. subendothelial lipid deposits, valve sclerosis, and neo-intima in the aorta. We performed a preliminary, qualitative, comparative study of the lesions associated with the different animal populations and valvular phenotypes. Our results indicate that (1) the type and severity of the lesions varied among the three hamster populations, suggesting that genetic factors may be involved; (2) the aortic valve morphology seems not to determine the severity of the valvular lesions. We conclude that our hamster strain with high incidence of BAV is a promising animal model for studies on human aortic stenosis. This work was supported by P10-CTS-6068.Universidad de Málaga. Campus de Excelencia Andalucía Tech. P10-CTS-6068

Las dimensiones de la búsqueda de sensaciones en la compra online del turista

Las tecnologías de la información están transformando los modelos de comportamiento de compra de los mercados turísticos, favoreciendo que el turista organice sus viajes de forma independiente. Para ello ha sido fundamental el rápido desarrollo de Internet en todo el mundo, aunque el comercio electrónico ha seguido un proceso más lento. Sin embargo, las cifras de ventas online son muy distintas según el tipo de producto. Así, los productos turísticos son los más adquiridos a través de Internet. La 10ª Encuesta sobre Usuarios de Internet en España realizada por la Asociación para la Investigación de Medios de Comunicación (2008) señala que un 29,6% de las ventas online son debidas a los siguientes tipos de productos: transporte de pasajeros, alojamiento y paquetes turísticos. Los estudios sobre el comportamiento de compra online suelen centrarse en los aspectos sociodemográficos, dedicando poca atención a los aspectos más psicológicos de las personas. El presente trabajo trata de analizar el comportamiento de los internautas que realizan reservas online de productos turísticos, indagando en uno de los rasgos de personalidad como es el de la búsqueda de sensaciones. Este rasgo se entiende como un deseo de tener sensaciones y experiencias variadas, novedosas, complejas e intensas, así como la disposición para asumir riesgos físicos, sociales, legales y económicos en aras a conseguir dicha experiencia. Se identifican cuatro componentes de la búsqueda de sensaciones, como son: 1) búsqueda de emoción y aventura; 2) búsqueda de experiencia; 3) desinhibición; y 4) susceptibilidad al aburrimiento. El presente estudio se basa en una muestra de 457 estudiantes universitarios, que representan uno de los mercados potenciales más relevantes en el comercio electrónico. En los resultados del estudio se ha detectado que los compradores online puntúan más alto en la escala total de búsqueda de sensaciones que los no compradores y, además, se observa que hay diferencias significativas entre compradores y no compradores de productos turísticos por Internet respecto a la subescala de la búsqueda de emoción y aventura y a la subescala de la susceptibilidad al aburrimiento. No obstante, tan sólo las mujeres son las que reciben la influencia del rasgo de personalidad de búsqueda de sensaciones respecto a la compra online de productos turísticos.Patterns of buying behavior of the tourist markets are being changed by information technologies, encouraging tourists to arrange their trips on their own. To that end, the rapid development of Internet in the world has been critical, although the expansion of electronic commerce has been slower. However, online sales are very different depending on the product. Thus, tourism products are the most purchased of all over the internet. The 10th Survey of Internet Users in Spain by the Association for Research in the Media (2008) noted that 29.6 % of online sales are due to the following types of products: passenger transport, accommodation, and travel package. Studies of online buying behavior typically focus on the socio-demographic characteristics, devoting little attention to psychological aspects of people. This paper analyzes the behavior of Internet users engaged in online booking of tourism products, and investigates one of their personality features: the sensation seeking. This feature is defined as the seeking of varied, new, and complex experiences, and the willingness to take physical, social, legal, and financial risks in order to achieve such experience. Four components of sensation seeking are identified: 1) thrill and adventure seeking, 2) experience seeking, 3) disinhibition, and 4) boredom susceptibility. This study is based on a sample of 457 university students, who represent one of the most important potential markets for e-commerce. The study has found that online buyers attain higher scores in the full scale of sensation seeking than non-buyers, and also shows that there are significant differences between buyers and non-buyers of tourism products over the Internet with regard to two subscales: the thrill and adventure seeking and the boredom susceptibility. However, only women receive the influence of personality feature of sensation seeking with respect to the purchase of tourism products online

Comportamiento ecológico de los gestores de campos de golf en Andalucía (España)

La práctica del golf tiene un gran potencial turístico en países como España o en regiones como Andalucía. Pero es necesario cuidar de su desarrollo para que se haga de una manera racional y equilibrada. Recientemente, la Comunidad Autónoma de Andalucía ha aprobado una nueva normativa que regula las condiciones de implantación y funcionamiento de los campos de golf andaluces. Este trabajo presenta los resultados de un estudio realizado sobre la sostenibilidad de los campos de golf en Andalucía desde la perspectiva empresarial. Entre los principales resultados, se puede destacar que los directivos de campos de golf se sienten motivados en su comportamiento ecológico fundamentalmente por la necesidad de satisfacer aspectos empresariales (imagen y responsabilidad social), quedando en un segundo plano otros factores propios de su entorno, como las demandas de los jugadores, la influencia de la legislación y la de los grupos ecologistas