Claws and toepads in mainland and island Anolis (Squamata: Dactyloidae): Different adaptive radiations with intersectional morphospatial zones.

Anolis lizards have evolved morphologies in response to different selective factors related to microhabitat use. Morphological diversity exhibits evolutionary patterns that reveal similarities and unique regional traits among the mainland and island environments and among Greater Antilles and Lesser Antilles islands. In the Greater Antilles and mainland environments anole species are classified into morphological/ecological groups, that are known as morphotypes (mainland) or ecomorphs (Greater Antilles). Morphotypes are defined only with morphological information; in contrast, for ecomorph assignment both morphology and ethology are required. For mainland species distributed in northwestern South America 10 morphotypes were proposed to include the morphological diversity of 59 species. We obtained data from body size, limbs length, tail length, and the number of lamellae for an additional ten species occurring in the same region and assigned them into morphotypes. We also collected data of the claw and toepad diversity of mainland and island Anolis from northwestern South America and compared it to the claw and toepads morphology recorded for the Greater Antilles and Lesser Antilles islands, under a phylogenetic framework. We found new island morphotypes (MT11-MT13) of Anolis from northwestern South America. When comparing claws and toepads morphology among the 13 morphotypes we found that morphological variation of these traits partially corresponds to morphotype groups. For instance, habitat specialist species like Anolis heterodermus, classified in morphotype 4 (MT4), have a characteristic design of broad toepad and reduced claws, and non-unique design of toepads and claws occurs in morphotypes MT1, MT2, MT5, MT10, and MT13. We also compared claws and toepads of fore and hindlimbs within the same individual, and found that even if limbs show differences in claws and toepads, suggesting that they perform differential biomechanical function, the degree of within individual variation is specific and not related to morphotype assignment. Our data supported the convergent and unique regional evolution among mainland and island anoles, and revealed aspects of correlative evolution of functional traits of claws and toepads that probably are related to minor differences in microhabitat use among mainland and island species, as suggested by previously published literature. Lastly, the evolutionary pattern of morphological diversity of claws and toepads of Anolis in the mainland and island environment supports both unique regional traits and common selective and historical factors that have molded Anolis morphological diversity.

Do blood parasites increase immature erythrocytes and mitosis in amphibians? / ¿Causan los parásitos sanguíneos un aumento en los eritrocitos inmaduros y la mitosis en los anfibios?

Abstract Introduction: In amphibians, blood may act as a hematopoietic tissue. However, the knowledge concerning hematological features is scarce, there is not much information that allows an analysis about the possible explanations of this physiological feature. Objective: This study aimed to evaluate the relationship between immature red blood cells (RBCs) mitosis and the presence of blood parasites in amphibians. Methods: We sampled 116 amphibians (31 species) in six Colombian localities. Blood was taken by cardiac puncture or maxillary vein puncture. Smears were prepared, fixed, and Giemsa stained for microscopical analysis. The variables analyzed were the percentage of immature RBCs, mitotic cells in peripheral blood, and blood parasite infection. Data were analyzed using Wilcoxon's rank test and exact Fisher statistical tests. Results: Sixty-two individuals showed mitosis in peripheral blood, and these mitotic RBCs shared morphological features with immature RBCs. Overall, parasite prevalence was 30.1 %, distributed as follows: Trypanosoma (24.1 %), Hepatozoon-like (6 %), Dactylosoma (4.3 %), Karyolysus-like (0.9 %), and Filarioidea (2.6 %). A positive association between the percentage of immature RBCs and the presence of mitotic RBCs was found, and also between the blood parasite infection and the percentage of immature RBCs. Conclusions: In this study, we found that the presence of blood parasites, immature RBCs, and RBCs mitosis are frequent events in amphibians' peripheral blood, and our analysis suggests an association between those features. Thus, the release of immature RBCs and the mitosis of those cells in peripheral blood may be a physiological response to blood parasite infection. Further studies characterizing hematology in amphibians and wildlife, in general, are desirable.

Resumen Introducción: En anfibios, la sangre puede actuar como un tejido hematopoyético. Sin embargo, el conocimiento acerca de las características hematológicas es escaso y no hay información que permita un análisis acerca de las posibles explicaciones a este rasgo fisiológico. Objetivo: La intención de este estudio fue evaluar la relación entre la presencia de eritroblastos, mitosis de glóbulos rojos (GRs) y la infección por hemoparásito en sangre periférica de anfibios. Métodos: Se muestrearon 116 anfibios (31 especies) en seis localidades de Colombia. Se tomaron muestras de sangre mediante punción cardiaca o punción a la vena maxilar. Se prepararon extendidos sanguíneos, se fijaron y tiñeron con Giemsa para su posterior análisis por microscopía. Se analizaron variables como porcentaje de GRs inmaduros, células mitóticas en sangre periférica e infección por hemoparásitos. Los datos fueron analizados mediante el test de rango de Willcoxon y el test exacto de Fisher. Resultados: sesenta y dos individuos evidenciaron mitosis en sangre periférica y dichas mitosis compartían características morfológicas con GRs inmaduros. La prevalencia general de parásitos fue del 30.1 %, distribuido de la siguiente forma: Trypanosoma (24.1 %), Hepatozoon-like (6 %), Dactylosoma (4.3 %), Karyolysus-like (0.9 %), y Filarioidea (2. 6 %). Hay una asociación positiva entre el porcentaje de GRs inmaduros y la presencia de células mitóticas, también se encontró una relación entre la infección por hemoparásitos y el porcentaje de GRs inmaduros. Conclusiones: En este estudio encontramos que la presencia de parásitos sanguíneos, GRs inmaduros y mitosis de GRs son eventos frecuentes en sangre periférica de anfibios, y nuestros resultados sugieren una asociación entre dichas características. Por tanto, la liberación de GRs inmaduros y la mitosis de estas células en sangre periférica podría ser una respuesta fisiológica a infecciones parasitarias. Posteriores estudios que caractericen la hematología en anfibios y en vida silvestre en general, son deseables.

The highest kingdom of Anolis: Thermal biology of the Andean lizard Anolis heterodermus (Squamata: Dactyloidae) over an elevational gradient in the Eastern Cordillera of Colombia.

Vertebrate ectotherms may deal with changes of environmental temperatures by behavioral and/or physiological mechanisms. Reptiles inhabiting tropical highlands face extreme fluctuating daily temperatures, and extreme values and intervals of fluctuations vary with altitude. Anolis heterodermus occurs between 1800 m to 3750 m elevation in the tropical Andes, and is the Anolis species found at the highest altitude known. We evaluated which strategies populations from elevations of 2200 m, 2650 m and 3400 m use to cope with environmental temperatures. We measured body, preferred, critical maximum and minimum temperatures, and sprint speed at different body temperatures of individuals, as well as operative temperatures. Anolis heterodermus exhibits behavioral adjustments in response to changes in environmental temperatures across altitudes. Likewise, physiological traits exhibit intrapopulation variations, but they are similar among populations, tended to the "static" side of the evolution of thermal traits spectrum. The thermoregulatory behavioral strategy in this species is extremely plastic, and lizards adjust even to fluctuating environmental conditions from day to day. Unlike other Anolis species, at low thermal quality of the habitat, lizards are thermoconformers, particularly at the highest altitudes, where cloudy days can intensify this strategy even more. Our study reveals that the pattern of strategies for dealing with thermal ambient variations and their relation to extinction risks in the tropics that are caused by global warming is perhaps more complex for lizards than previously thought.

Función de los confórmeros de ataque cercano en la acilación enantioselectiva del (R,S)-propranolol catalizada por lipasa B de Candida antárctica / Rol of the near attack conformers during enantioselective acylation of (R,S)-propranolol catalysed by Candida antarctica lipase B

RESUMEN La lipasa B de Candida antárctica (CalB) se ha utilizado en la acilación quimio- y enantioselectiva del racemato (R,S)-propranolol. CalB tiene enant¡oselect¡v¡dad moderada (£=63) por el R-propranolol. La enantioselectividad, se origina en la reacción de transferencia del grupo acilo desde la serina catalítica, acilada, al propranolol. La fase inicial de esta reacción involucra la formación de complejos de Michaelis y posteriormente conformaciones de ataque cercano. El análisis de las conformaciones de ataque cercano ha permitido en varios casos explicar el origen de la catálisis o reproducir el efecto catalítico. En este trabajo se profundiza en la comprensión la función de las conformaciones de ataque cercano en la enantioselectividad de la acilación del (R,S)-propranolol catalizada por CalB. Para lo anterior se realizó un estudio detallado de los complejos de Michaelis y de las conformaciones de ataque cercano del paso enantioselectivo de la reacción de acilación del (R,S)-propranolol utilizando un protocolo de dinámica molecular QM/MM (SCCDFTB/CHARMM) utilizando 6 distribuciones de velocidades iniciales y simulaciones de 2,5 ns. Se estudiaron 7 complejos CalB-propranolol. Los enlaces de hidrógeno del sitio activo de CalB acilada relevantes para la actividad catalítica fueron estables en todas las simulaciones. Las poblaciones de los complejos de Michaelis y de las conformaciones de ataque cercano son dependientes de la distribución de las velocidades iniciales de la dinámica molecular. La enantioselectividad moderada de CalB acilada, encontrada experimentalmente, puede ser parcialmente atribuida a la alta población de conformaciones de ataque cercano observada para el S-propranolol.

ABSTRACT Candida antarctica lipase B (CalB) has been used for chemo- and enantioselective acylation of racemic (R,S)-propranolol, with moderate enantioselectivity (£=63) for R-propranolol. The enantioselective step in this reaction is the transfer of an acyl group from the catalytic acylated serine to propranolol. The initial phase of this reaction involves the formation of Michaelis complexes, followed by the formation of near-attack complexes. The analysis of the near-attack complexes has in several cases permitted to explain the origin of the catalysis or to reproduce the catalytic effect. The aim of this study was improve the understanding of the role of the near-attack complexes for the enantioselectivity of the acylation of (R,S)-propranolol, catalyzed by CalB. To this purpose a detailed investigation of the Michaelis and near-attack complexes of the enantioselective step of the acylation of (R,S)-propranolol using QM/MM molecular dynamics was performed. Several simulations (each 2,5 ns) with different initial velocity distributions were performed. In total seven CalB-propranolol complexes were studied. The hydrogen bonds in the active site of CalB, which are relevant for the catalytic activity, are stable in all simulations. The lifetime of the Michaelis complexes is considerably shorter than the simulation time. Conclusions: The populations of the Michaelis and near-attack complexes depend on the initial velocity distribution in the molecular dynamics simulations. The experimentally observed moderate enantioselectivity may be partially attributed to the high population of near-attack conformations of S-propranolol.

Plasmodium parasites in reptiles from the Colombia Orinoco-Amazon basin: a re-description of Plasmodium kentropyxi Lainson R, Landau I, Paperna I, 2001 and Plasmodium carmelinoi Lainson R, Franco CM, da Matta R, 2010.

Colombia is a megadiverse country with about 600 species of reptiles; however, there are few studies on species of hemoparasites found in this taxonomic group. Here, we document the presence of Plasmodium spp. in four species of reptiles from the northern part of the Orinoco-Amazon region in Colombia. Individuals analyzed in this study were captured in localities between 200 and 500 m altitude, in the department of Guaviare. Each sample was screened for haemosporidian parasites by using morphology and a nested polymerase chain reaction (PCR) protocol that targets the mitochondrial cytochrome b (cytb) gene. Four morphotypes of the genus Plasmodium were found; two of these species are re-described using morphological and molecular data (cytb). For the other two morphotypes, it was not possible to assign a described species. Among those, Plasmodium screened one species was only detected by microscopy. Considering the potential species diversity, it is possible that commonly used primers may not detect all species, reinforcing the importance of using microscopy in haematozoa surveys. There was no correspondence between the morphological traits associated with the subgenera and the phylogenetic relationships that we found in our analyses. Additionally, we found an expansion in the geographical distribution of these two species, and a new host for P. kentropyxi, demonstrating that studies of tropical herpetofauna and their parasites deserve more attention.

A new Lepidoblepharis lizard (Squamata: Sphaerodactylidae) from the Colombian Guyana shield.

Lepidoblepharis lizards are tiny geckos of the forest leaf litter. This genus is distributed from Nicaragua to the Amazonian region of Peru and Brazil, and the genus currently contains 21 species. We found a new small Lepidoblepharis from eastern Colombia that we here describe as a new species. It is characterized by having granular or subconical dorsal scales; 10-13 subdigital lamellae under 4th toe; postmental border slightly or strongly projecting backwards, followed by 2-5 (usually 3) postmentals; and 20-31 scales across snout at lst/2nd supralabial suture. This new taxon is compared to all congeners.

Determinación del nivel de preparación metodológica del profesor para desarrollar tareas docentes integradoras en Morfofisiología / Determination of the level of methodological preparation of the professors to develop integrative teaching tasks in Morphology- physiology

Fundamento: la tarea docente constituye la célula fundamental del proceso docente educativo, por lo que su confección y utilización constituyen premisas para el buen desempeño escolar. Objetivo: determinar el estado actual de la preparación metodológica del profesor para desarrollar tareas docentes integradoras en la disciplina Morfofisiología. Métodos: se realizó una investigación descriptiva transversal, la población de estudioestuvo conformada por los profesores que imparten la disciplina Morfofisiología en el área sur de la Universidad de Ciencias Médicas de Ciego de Ávila. Se aplicaron métodos teóricos: histórico-lógico, analítico-sintético e inductivo-deductivo; empíricos: análisis documental,observación a clases y encuesta en forma de cuestionario a docentes y de entrevista a informantes clave.Resultados: la tarea docente integradora no ha constituido un elemento de prioridad en lapreparación del profesor, algunos no tienen en cuenta el algoritmo a seguir durante sus etapas de diseño, orientación, ejecución y control; existe insuficiente continuidad de temasafines y algunas insuficiencias en el dominio de contenidos, sobre todo de aquellos que no se relacionan directamente con las especialidades de los docentes. Conclusiones: las limitaciones identificadas para el desarrollo de tareas docentes afectan laintegración que deben tener las asignaturas dentro de la propia disciplina Morfofisiología y con la disciplina rectora Medicina General Integral, para lograr un enfoque interdisciplinario en la formación del estudiante de las ciencias médicas(AU)

Molecular phylogenetics and biogeography of the Neotropical skink genus Mabuya Fitzinger (Squamata: Scincidae) with emphasis on Colombian populations.

Understanding the phylogenetic and geographical history of Neotropical lineages requires having adequate geographic and taxonomic sampling across the region. However, Colombia has remained a geographical gap in many studies of Neotropical diversity. Here we present a study of Neotropical skinks of the genus Mabuya, reptiles that are difficult to identify or delimit due to their conservative morphology. The goal of the present study is to propose phylogenetic and biogeographic hypotheses of Mabuya including samples from the previously under-studied territory of Colombia, and address relevant biogeographic and taxonomic issues. We combined molecular and morphological data sampled densely by us within Colombia with published data representing broad sampling across the Neotropical realm, including DNA sequence data from two mitochondrial (12S rRNA and cytochrome b) and three nuclear genes (Rag2, NGFB and R35). To evaluate species boundaries we employed a general mixed Yule-coalescent (GMYC) model applied to the mitochondrial data set. Our results suggest that the diversity of Mabuya within Colombia is higher than previously recognized, and includes lineages from Central America and from eastern and southern South America. The genus appears to have originated in eastern South America in the Early Miocene, with subsequent expansions into Central America and the Caribbean in the Late Miocene, including at least six oceanic dispersal events to Caribbean Islands. We identified at least four new candidate species for Colombia and two species that were not previously reported in Colombia. The populations of northeastern Colombia can be assigned to M. zuliae, while specimens from Orinoquia and the eastern foothills of the Cordillera Oriental of Colombia correspond to M. altamazonica. The validity of seven species of Mabuya sensu lato was not supported due to a combination of three factors: (1) non-monophyly, (2) <75% likelihood bootstrap support and <0.95 Bayesian posterior probability, and (3) GMYC analysis collapsing named species. Finally, we suggest that Mabuya sensu stricto may be regarded as a diverse monophyletic genus, widely distributed throughout the Neotropics.

Estimating the temporal and spatial extent of gene flow among sympatric lizard populations (genus Sceloporus) in the southern Mexican highlands.

Interspecific gene flow is pervasive throughout the tree of life. Although detecting gene flow between populations has been facilitated by new analytical approaches, determining the timing and geography of hybridization has remained difficult, particularly for historical gene flow. A geographically explicit phylogenetic approach is needed to determine the overlap of ancestral populations. In this study, we performed population genetic analyses, species delimitation, simulations and a recently developed approach of species tree diffusion to infer the phylogeographic history, timing and geographic extent of gene flow in lizards of the Sceloporus spinosus group. The two species in this group, S. spinosus and S. horridus, are distributed in eastern and western portions of Mexico, respectively, but populations of these species are sympatric in the southern Mexican highlands. We generated data consisting of three mitochondrial genes and eight nuclear loci for 148 and 68 individuals, respectively. We delimited six lineages in this group, but found strong evidence of mito-nuclear discordance in sympatric populations of S. spinosus and S. horridus owing to mitochondrial introgression. We used coalescent simulations to differentiate ancestral gene flow from secondary contact, but found mixed support for these two models. Bayesian phylogeography indicated more than 60% range overlap between ancestral S. spinosus and S. horridus populations since the time of their divergence. Isolation-migration analyses, however, revealed near-zero levels of gene flow between these ancestral populations. Interpreting results from both simulations and empirical data indicate that despite a long history of sympatry among these two species, gene flow in this group has only recently occurred.

GEOGRAPHIC BODY SIZE AND SHAPE VARIATION IN A MAINLAND Anolis (SQUAMATA: DACTYLOIDAE)FROM NORTHWESTERN SOUTH AMERICA (COLOMBIA) / Variación geográfica en tamaño y forma corporalen un Anolis (Squamata: Dactyloidae) continental del noroeste de Suramérica (Colombia)

Anolis auratus is a widely distributed species, from Costa Rica in Central America, through northern South America, including Colombia, Venezuela, northern Brazil, Surinam and the Guyanas. In Colombia, its widespread distribution across different life zones suggests that these lizards occupy different environments and exhibit different microhabitat use in different geographic areas. On the other hand, some observations suggest that this species prefers open areas, selecting grasslands over brushy areas, and thus, an alternative hypothesis is that microhabitat use is similar among different populations. In Anolis, body variables related to locomotion (body size and shape) define structural microhabitat use, so two distinct patterns could be expected in this species: conservative or highly variable body size and shape throughout the species distribution. To test these predictions, we characterized geographic variation in morphometric traits of this species in Colombia. Females and males were similar in body size, but exhibited differences in some variables related to body shape. These characteristics also varied among males and females from different regions, suggesting heterogeneous use of structural microhabitat, between sexes and among populations. As an alternative, phylogenetic divergence among populations could also account for the observed differences. Absence of ecological and phylogenetic data limits our ability to identify the underlying causes of this pattern. However, we provide a general framework to explore hypotheses about evolution of body size and shape in this species.

Anolis auratus se distribuye desde Costa Rica en Centro América, el norte de Sur América, incluyendo Colombia, Venezuela, norte de Brasil, Surinam y las Guyanas. En Colombia, su amplia distribución en distintas zonas de vida sugiere que estos lagartos ocupan distintos ambientes, y por tanto, posiblemente exhiben variación geográfica en el uso de microhabitat. Por otra parte, algunas observaciones sugieren que estos lagartos prefieren zonas abiertas, seleccionando pastizales y por tanto, una hipótesis alternativa es que usan el mismo microhabitat en toda su distribución. En Anolis, las variables corporales relacionadas con el movimiento (tamaño y forma corporal) definen el uso del microhabitat, así que pueden esperarse dos patrones en esta especie: tamaño y forma corporal conservativos o altamente variables a lo largo de su distribución. Caracterizamos la variación geográfica en variables morfométricas de esta especie en Colombia. Hembras y machos mostraron tamaño corporal similar, pero fueron distintos en la forma del cuerpo. La forma corporal varía también en machos y hembras de distintas regiones, sugiriendo un uso heterogéneo del microhabitat estructural. Como alternativa, la divergencia filogenética entre poblaciones podría explicar las diferencias observadas. La ausencia de datos ecológicos y filogenéticos para la especie limita las hipótesis sobre causas de este patrón. Proveemos un marco general para explorar hipótesis que expliquen la evolución de tamaño y forma corporal en esta especie.

Intraspecific variation in body size and shape in an andean highland anole species, Anolis ventrimaculatus (Squamata: Dactyloidae).

Variation in body characteristics related to lizard locomotion has been poorly studied at the intraspecific level in Anolis species. Local adaptation due to habitat heterogeneity has been reported in some island species. However, studies of mainland species are particularly scarce and suggest different patterns: high variability among highland lizards and poorly differentiated populations in one Amazonian species. We characterized inter population variation of body size and shape in the highland Andean Anolis ventrimaculatus, an endemic species from Western Colombia. A total of 15 morphometric variables were measured in specimens from the reptile collection of the Instituto de Ciencias Naturales, Universidad Nacional, Colombia. The study included individuals from seven different highland localities. We found size and shape sexual dimorphism, both of which varied among localities. Patterns of variation in body proportions among populations were different in both males and females, suggesting that either sexual or natural selective factors are different in each locality and between sexes. Since this species exhibits a fragmented distribution in highlands, genetic divergence may also be a causal factor of the observed variation. Ecological, behavioral, additional morphological as well as phylogenetic data, may help to understand the evolutionary processes behind the geographic patterns found in this species.

Intraspecific variation in body size and shape in an Andean highland anole species, Anolis ventrimaculatus (Squamata: Dactyloidae)

Variation in body characteristics related to lizard locomotion has been poorly studied at the intraspecific level in Anolis species. Local adaptation due to habitat heterogeneity has been reported in some island species. However, studies of mainland species are particularly scarce and suggest different patterns: high variability among highland lizards and poorly differentiated populations in one Amazonian species. We characterized inter population variation of body size and shape in the highland Andean Anolis ventrimaculatus, an endemic species from Western Colombia. A total of 15 morphometric variables were measured in specimens from the reptile collection of the Instituto de Ciencias Naturales, Universidad Nacional, Colombia. The study included individuals from seven different highland localities. We found size and shape sexual dimorphism, both of which varied among localities. Patterns of variation in body proportions among populations were different in both males and females, suggesting that either sexual or natural selective factors are different in each locality and between sexes. Since this species exhibits a fragmented distribution in highlands, genetic divergence may also be a causal factor of the observed variation. Ecological, behavioral, additional morphological as well as phylogenetic data, may help to understand the evolutionary processes behind the geographic patterns found in this species.

La diversificación fenotípica al interior de una especie en características de dimensiones corporales relacionadas con la locomoción de los lagartos, se ha estudiado poco en especies de Anolis. Los datos de algunas especies de isla revelan patrones distintos de variación geográfica y sugieren que la adaptación local, debida a la heterogeneidad del hábitat, ocurre a este nivel. Los estudios de especies de continente son particularmente escasos y sugieren patrones distintos: un lagarto altoandino altamente variable y poblaciones poco diferenciadas en una especie amazónica. Caracterizamos la variación inter poblacional en el tamaño y forma del cuerpo del lagarto altoandino Anolis ventrimaculatus, especie endémica del Oeste de Colombia. Encontramos variación geográfica en el dimorfismo sexual en tamaño y forma. El patrón de variación en las proporciones corporales entre poblaciones fue distinto en machos y en hembras, sugiriendo que las presiones de selección sexual o natural son diferentes en cada localidad. Dado que la especie exhibe una distribución fragmentada en alta montaña, la divergencia genética entre poblaciones puede ser otro factor causal de la variación observada. Datos ecológicos, etológicos y morfológicos adicionales, así como información filogenética puede contribuir al entendimiento de los procesos evolutivos responsables del patrón de variación geográfica encontrado en esta especie.

Regulation of histone modification and chromatin structure by the p53-PADI4 pathway.

Histone proteins are modified in response to various external signals; however, their mechanisms are still not fully understood. Citrullination is a post-transcriptional modification that converts arginine in proteins into citrulline. Here we show in vivo and in vitro citrullination of the arginine 3 residue of histone H4 (cit-H4R3) in response to DNA damage through the p53-PADI4 pathway. We also show DNA damage-induced citrullination of Lamin C. Cit-H4R3 and citrullinated Lamin C localize around fragmented nuclei in apoptotic cells. Ectopic expression of PADI4 leads to chromatin decondensation and promotes DNA cleavage, whereas Padi4(-/-) mice exhibit resistance to radiation-induced apoptosis in the thymus. Furthermore, the level of cit-H4R3 is negatively correlated with p53 protein expression and with tumour size in non-small cell lung cancer tissues. Our findings reveal that cit-H4R3 may be an 'apoptotic histone code' to detect damaged cells and induce nuclear fragmentation, which has a crucial role in carcinogenesis.

Erosion of lizard diversity by climate change and altered thermal niches.

It is predicted that climate change will cause species extinctions and distributional shifts in coming decades, but data to validate these predictions are relatively scarce. Here, we compare recent and historical surveys for 48 Mexican lizard species at 200 sites. Since 1975, 12% of local populations have gone extinct. We verified physiological models of extinction risk with observed local extinctions and extended projections worldwide. Since 1975, we estimate that 4% of local populations have gone extinct worldwide, but by 2080 local extinctions are projected to reach 39% worldwide, and species extinctions may reach 20%. Global extinction projections were validated with local extinctions observed from 1975 to 2009 for regional biotas on four other continents, suggesting that lizards have already crossed a threshold for extinctions caused by climate change.

Risk of Giardia intestinalis infection in children from an artificially recharged groundwater area in Mexico City.

The objective of this study was to assess the risk of infection with Giardia intestinalis in children living in an area with artificial groundwater recharge and potable water reuse in Mexico City. Eligible wells and surrounding homesteads were defined by using a geographic information system. Five wells were tested for G. intestinalis cysts per 400 liters of water. A total of 750 eligible households were visited during two cross-sectional surveys. Stool samples were provided by 986 children in the rainy season study and 928 children during the dry season survey for parasitologic tests. Their guardians provided information on water, sanitation, hygiene, and socioeconomic variables. The prevalence rates of G. intestinalis infection were 9.4% in the rainy season and 4.4% in the dry season. Higher rates of infection were observed in older individuals (9.5% and 10.6%) and girls had a lower risk of infection than boys (odds ratio [OR] =0.55, 95% confidence interval [CI] = 0.34, 0.88 in the rainy season and OR = 0.47, 95% CI = 0.25, 0.90 in the dry season). During the wet season survey, a health risk was detected among those storing water in unprotected receptacles (OR = 4.00, 4.69, and 5.34 for those using uncovered jars, cisterns or tanks, and buckets, respectively), and bathing outside the dwelling, i.e., using a tap (OR = 1.93, 95% CI = 1.10, 3.39). A health risk was also detected among children from households with unsafe food hygiene practices (OR =2.41, 95% CI =1.10, 5.30) and those with no hand-washing habits (OR = 2.27, 95% CI = 1.00, 5.20). Groundwater reserves are at risk of fecal pollution, as indicated by the presence of G. intestinalis cysts. However, the endemic pattern of intestinal infection reflects low standards of personal hygiene and unsafe drinking water storage and food-related practices at household level. Prevention activities must address health education and environmental protection policies.

Cambios periodontales, relacionados con la lesión producida por el tornillo de osteosíntesis. Estudio histológico piloto en perros / Periodontal changes related with the lesion produced by osteosynthesis screw. A histological pilot study in dogs

En cirugía maxilofacial al realizar fijación rígida (placas y tornillos de osteosíntesis) en casos de facturas maxilares y/o mandibulares, cerca de las estructuras dentales, existe riesgo de daño periodontal ocasionado accidentalmente por el tornillo, lo qu determina un pronóstico periodontal incierto, a corto plazo. No se ha encontrado en la literatura ningún reporte sobre los cambios periodontales frente a la lesión ocasionada por un tornillo de osteosíntesis. Este estudio se diseño con el objeto de comparar la frecuencia de hallazgos histológicos cuando en forma accidental un tornillo compromete los tejidos periodontales y se preserva, con los hallazgos en un grupo en el que es retirado el tornillo que causó la injuria periodontal. El estudio se llevó a cabo en cuatro perros machos, jóvenes (1 a 3 años), con un peso entre 11 y 15 kilogramos, sistémica y periodontalmente sanos, a los cuales se les colocaron en total 32 minitornillos de Titanio de osteosíntesis de marca leibinger (ocho tornillos por perro), a nivel del tercio medio radicular de los caninos, primeros molares inferiores y cuartos premolares superiores, en dirección tangencial al diente e involucrando únicamente dentina y tejidos periodontales, sin afectar la pulpa. La respuesta clínica se evaluó un mes después de la cirugía, cuando se retiraron los tornillos de la hemiarcada superior e inferior del lado derecho. Al mes siguiente (a los 60 días), se realizó el sacrificio de los animales y se procedió a realizar el estudio histológico de 16 parámetros. Los resultados se evaluaron con la prueba de chi cuadrado, la cual indica que hay diferencias significativas en la frecuencia de los siguientes hallazgos, al comparar los sitios donde se dejó el tornillo con los sitos en donde se retiró: pérdida ósea; tejido conjuntivo fibroso en el nicho; infiltrado inflamatorio en el nicho; fibrosis del ligamento y trabeculado óseo medular. Estos hallazgos permiten concluir que se preserva más la salud del tejido periodontal cuando se retira el tornillo.