Microhabitat and associated biota of abalone juveniles, Haliotis fulgens and H. corrugata, in Bahía Tortugas, Baja California Sur, Mexico

Abalone is an important economical resource on the west coast of Baja California. The most important species in this fishery are green and pink abalone (Haliotis fulgens and H. corrugata, respectively). Overfishing has been implicated in the decline of the Mexican abalone fishery. Among the population parameters, recruitment is a highly variable event. To obtain a better understanding of the ecology of abalone juvenile recruitment, the physical and biological characteristics of the microhabitat of juveniles of green and pink abalone were studied at Bahía Tortugas, Baja California Sur (Mexico), during autumn and spring from 1996 to 1998. Two abalone reefs with different depth, relief and wave exposure were surveyed: Clam Bay, with depths of 0.5 to 5 m, and Morro de Adentro, with depths of 6 to 12 m. Four different bottom types were recognized: (a) sheltered and low relief bottom, (b) semiexposed and moderate relief bottom, (c) exposed and high relief bottom, and (d) exposed and moderate relief bottom. Juveniles of green and pink abalone from 3 to 13 mm shell length were observed under small rocks, pebbles and flat stones no longer than 15|00E2|??20 cm, always covered with crusts of coralline algae. Several tiny juveniles of Fisurella, Stenoplax, and Crepipatella of similar sizes (5–10 mm) shared the microhabitat. Juveniles between 15 and 90 mm shell length were found under flat, rhombic or irregular-shaped rocks (20–110 mm length), most of them deployed in imbricate arrangement. Abalone juveniles shared this microhabitat with bryozoans, sponges, ascidians, chitons, and annelids. Bottoms with imbricate arrangement, low wave exposure, and the low depth of Clam Bay were favorable for the high occurrence of juveniles of H. fulgens. Juveniles of H. corrugata showed a high occurrence in exposed and deeper zones of Morro de Adentro

Eag1 channels as potential early-stage biomarkers of hepatocellular carcinoma

María de Guadalupe Chávez-López,1 Violeta Zúñiga-García,1 Julio Isael Pérez-Carreón,2 Arturo Avalos-Fuentes,3 Yesenia Escobar,4 Javier Camacho1 1Department of Pharmacology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, 2Instituto Nacional de Medicina Genómica, 3Department of Physiology, Biophysics and Neuroscience, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, 4Centro de Investigación Clínica Acelerada Sc, Mexico City, Mexico Abstract: Hepatocellular carcinoma (HCC) is a major cause of cancer death worldwide. HCC is usually asymptomatic at potential curative stages, and it has very poor prognosis if detected later. Thus, the identification of early biomarkers and novel therapies is essential to improve HCC patient survival. Ion channels have been proposed as potential tumor markers and therapeutic targets for several cancers including HCC. Especially, the ether à-go-go-1 (Eag1) voltage-gated potassium channel has been suggested as an early marker for HCC. Eag1 is overexpressed during HCC development from the cirrhotic and the preneoplastic lesions preceding HCC in a rat model. The channel is also overexpressed in human HCC. Astemizole has gained great interest as a potential anticancer drug because it targets several proteins involved in cancer including Eag1. Actually, in vivo studies have shown that astemizole may have clinical utility for HCC prevention and treatment. Here, we will review first some general aspects of HCC including the current biomarkers and therapies, and then we will focus on Eag1 channels as promising tools in the early diagnosis of HCC. Keywords: ion channels, Eag1, hepatocellular carcinoma, astemizole, diethylnitrosamin

Distribución y condiciones ecogeográficas del bosque relicto de Abies en zonas montañosas de Tamaulipas

Abstract: In the northeast of Mexico, the genus Abies forms forests considered relicts, with distribution only recognized by governmental instances for the state of Nuevo León. There are four species of Abies known within the state of Tamaulipas, which are listed by IUCN, but only two of them (A. vejarii and A. guatemalensis) form forests, being those found in Mexican protection categories. The use of free visualization tools and geospatial modeling allowed us to study the relict distribution of these Tamaulipan forests. We recorded ecogeographic factors from three sites in this forest, at the Field Control Points (PCC), which allowed to establish optical characteristics on satellite images of the Google Earth ™ viewer. With the values of altitude, slope and exposure, we obtained a first model (approximation model), using Boolean algebra with the Spatial Analyst module for ArcView 3.2 of ESRI ™, which was superimposed on the images of the visualizer, to adjust it and obtain a model principal. We added other points on the viewer in places where the INEGI records the presence of the forest in Nuevo León. Subsequently, the values for each of the WordlClim variables of the ten points obtained were extracted, establishing ranges that we processed through Boolean algebra; also, a cluster analysis was applied to obtain the bioclimatic similarity between the sites. The potential distribution was also superimposed on Google Earth ™ to repeat the adjustment process of the model and get the real distribution of the Tamaulipan forest. In this way, we obtained a potential area of 165.9 km2, but the actual distribution is only 3.68 km2, which represents less than 1% of the state territory. In the PCCs there are conditions of humidity and temperate temperature throughout the year, which are the product of the exposure and slope of the hillside; there, humidity depends on the altitude at the sites of the Sierra Madre Oriental, and on the proximity to the Gulf of Mexico in the forest of the Sierra de San Carlos. Which is the main differentiation variable between both sites. In addition to these conditions, other factors have allowed the prevalence of forests in Tamaulipas: they are not harvested commercially, mainly to their isolation and difficult access. Some sites of the potential distribution are occupied primarily by pine forests, but a large part of the surface has been affected mainly by fires, which means that there are chaparrals, shrubs, or induced grasslands. Because it is an isolated and relictual ecosystem, formed of species at risk and that also does not have legal protection, it can present significant levels of fragility and vulnerability, especially in the face of changing global climate conditions. Knowing their distribution provides the basis for more in-depth studies and conservation strategies appropriate to these forests. Finally, and despite the limitation of digital cartography in great detail, the geospatial tools and the method used were adequate to model the real distribution of the Abies forest in Tamaulipas, being more appropriate than the use of ecological niche algorithms, mainly due to which they depend on a high number of records.Resumen: En el noreste de México, el género Abies forma bosques considerados relictos, con distribución sólo reconocida por instancias gubernamentales para el estado de Nuevo León. Dentro del estado de Tamaulipas se conocen cuatro especies de Abies que se encuentran enlistadas por IUCN, pero sólo dos de ellas (A. vejarii y A. guatemalensis) forman bosques, siendo las que se encuentran en categorías mexicanas de protección. El uso de herramientas gratuitas de visualización y modelación geoespacial permitió estudiar la distribución relicta de estos bosques tamaulipecos. A través de Puntos de Control en Campo (PCC) se registraron factores ecogeográficos de tres sitios de este bosque, mismos que permitieron establecer características ópticas sobre imágenes de satélite del visualizador Google Earth™. Con los valores de altitud, pendiente y exposición, se obtuvo un primer modelo (de aproximación), usando álgebra booleana con el módulo Spatial Analyst para ArcView 3.2 de ESRI™, que se sobrepuso a las imágenes del visualizador, para ajustarlo y obtener un modelo principal. Este modelo sirvió, a su vez, como auxiliar para encontrar la distribución potencial, ya que primero se buscaron registros de Abies en bases de datos, los cuales se sobrepusieron al modelo principal en Google Earth™, para saber si se encontraban en sitios con características ópticas de bosque similares a los puntos de control; otros puntos fueron agregados sobre el visualizador en lugares donde el INEGI registra la presencia del bosque en Nuevo León. Posteriormente, se obtuvieron los valores para cada una de las variables de WordlClim de los diez puntos obtenidos, estableciendo rangos que fueron procesados a través de álgebra booleana; además, se aplicó un análisis de clústers para obtener la similitud bioclimática entre los sitios. La distribución potencial también fue sobrepuesta en Google Earth™ para repetir el proceso de ajuste del modelo y obtener así la distribución real del bosque de oyamel en Tamaulipas. De esta forma, se obtuvo como resultado una superficie potencial de 165.9 Km2, pero la distribución real es de apenas 3.68 Km2, lo que representa menos del 1% del territorio estatal. En los PCCs se presentan condiciones de humedad y temperatura templada todo el año, que son producto de la exposición e inclinación de la ladera; ahí, la humedad depende de la altitud en los sitios de la Sierra Madre Oriental, y de la cercanía al Golfo de México en el bosque de la Sierra de San Carlos; esta diferencia en la provisión de humedad es la variable de disgregación principal entre ambos sitios. Además de estas condiciones, otros factores han permitido la prevalencia de los bosques en Tamaulipas, principalmente a su aislamiento y acceso difícil, por lo que no son aprovechados comercialmente. Algunos lugares de la distribución potencial se encuentran ocupados principalmente por bosques de pino, pero gran parte de la superficie ha sido afectada principalmente por incendios, por lo que presentan chaparrales, matorrales o pastizales inducidos. Por ser un ecosistema aislado y relictual, formado de especies en riesgo y que además no cuenta con protección oficial, puede presentar niveles significativos de fragilidad y vulnerabilidad, especialmente ante las condiciones cambiantes del clima planetario. Conocer su distribución sienta bases para estudios más profundos y estrategias de conservación adecuadas a estos bosques. Finalmente, y a pesar de la limitación de cartografía digital a gran detalle, las herramientas geoespaciales y el método empleado resultaron adecuados para modelar la distribución real del bosque de Abies en el Tamaulipas, siendo más apropiado que el uso de algoritmos de nicho ecológico, debido principalmente a que estos dependen de un elevado número de registros