Institute Ciencias Medicas y Nutricion Salvador Zubiran

Mexico City, Mexico

Institute Ciencias Medicas y Nutricion Salvador Zubiran

Mexico City, Mexico
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Dias P.A.D.,University of Veracruz | Coyohua-Fuentes A.,University of Veracruz | Canales-Espinosa D.,University of Veracruz | Chavira-Ramirez R.,Institute Ciencias Medicas y Nutricion Salvador Zubiran | Rangel-Negrin A.,University of Veracruz
Hormones and Behavior | Year: 2017

Hormones have a key role in energy allocation, so their study allows understanding individual metabolic strategies. Because different hormones convey different information on the responses of individuals to energetic demands, a simultaneous analysis of variation in multiple hormones may offer a more reliable picture of metabolic strategies than single hormone assessments. In this study we focused on determining which factors were related to variation in fecal glucocorticoid and thyroid hormone metabolites in wild mantled howler monkeys (Alouatta palliata). Over 12 months, we determined fecal glucocorticoid and thyroid hormone metabolite levels of 11 adults belonging to two groups, and examined the relationship between hormone metabolites and a variety of behavioral, physiological, and ecological factors (e.g., food intake, sex/reproductive state, activity, participation in agonistic interactions). We found that glucocorticoids were elevated in gestating and lactating females compared to males and cycling females, and were also higher when individuals were more active and participated in agonistic interactions. Thyroid hormone levels were also related to sex/reproductive state and activity, but were additionally positively related to fruit intake and negatively related to young leaf intake. Our study demonstrates that the non-invasive measurement of glucocorticoid and thyroid hormones of howler monkeys allows assessing different underlying physiological processes. By combining different biomarkers, which has seldom been done with wildlife, we could also parse the influence of psychological vs. metabolic challenges for individual energetic condition, which may be instrumental for deciding which factors should be accounted for when studying different hormone-behavior interactions. © 2017 Elsevier Inc.

Dunn J.C.,University of Cambridge | Cristobal-Azkarate J.,University of Cambridge | Schulte-Herbruggen B.,Cambridge Assessment | Chavira R.,Institute Ciencias Medicas y Nutricion Salvador Zubiran | Vea J.J.,University of Barcelona
International Journal of Primatology | Year: 2013

Environmental stressors impact physiology in many animal species. Accordingly, the monitoring of fecal glucocorticoid metabolites (fGCM) has been increasingly used to evaluate the physiological costs of habitat disturbance on wild animal populations, providing a powerful tool for conservation and management. Several studies have suggested that primates in forest fragments have higher fGCM levels than those in continuous forests, yet the proximate causes of fGCM variation remain to be identified. In previous studies of Mexican howlers (Alouatta palliata mexicana) in Los Tuxtlas, Mexico, we found that individuals living in a smaller and more disturbed forest fragment consumed significantly less fruit and had a significantly higher feeding effort than those living in a bigger, more conserved forest fragment. Here, we aimed to examine the effects of fruit consumption and travel time on fGCM levels in the same two groups of howlers, during three sampling sessions that differed markedly in fruit availability. We found that fGCM levels (N = 202 fecal samples) were higher in the howler group living in the smaller forest fragment and varied seasonally in both focal groups, being lowest when fruit consumption was highest. However, our results suggest that travel time is the main factor predicting fGCM levels in howlers, and that although fruit consumption may be negatively related to fGCM levels, this relationship is probably mediated by the strong effect that fruit consumption has on travel time. Our results provide important insight into the proximate causes of fGCM variation in primates in fragments and highlight the potential conservation significance of studies showing that habitat loss and transformation can lead to increases in travel time in wild primates. © 2013 Springer Science+Business Media New York.

Aguilar-Melo A.R.,National Autonomous University of Mexico | Andresen E.,National Autonomous University of Mexico | Cristobal-Azkarate J.,University of Cambridge | Arroyo-Rodriguez V.,National Autonomous University of Mexico | And 5 more authors.
American Journal of Primatology | Year: 2013

Animals' responses to potentially threatening factors can provide important information for their conservation. Group size and human presence are potentially threatening factors to primates inhabiting small reserves used for recreation. We tested these hypotheses by evaluating behavioral and physiological responses in two groups of mantled howler monkeys (Alouatta palliata mexicana) at the "Centro Ecológico y Recreativo El Zapotal", a recreational forest reserve and zoo located in the Mexican state of Chiapas. Both groups presented fission-fusion dynamics, splitting into foraging subgroups which varied in size among, but not within days. Neither subgroup size nor number of people had an effect on fecal cortisol. Out of 16 behavioral response variables tested, the studied factors had effects on six: four were affected by subgroup size and two were affected by number of people. With increasing subgroup size, monkeys increased daily path lengths, rested less, increased foraging effort, and used more plant individuals for feeding. As the number of people increased, monkeys spent more time in lower-quality habitat, and less time engaged in social interactions. Although fecal cortisol levels were not affected by the factors studied, one of the monkey groups had almost twice the level of cortisol compared to the other group. The group with higher cortisol levels also spent significantly more time in the lower-quality habitat, compared to the other group. Our results suggest that particular behavioral adjustments might allow howler monkeys at El Zapotal to avoid physiological stress due to subgroup size and number of people. However, the fact that one of the monkey groups is showing increased cortisol levels may be interpreted as a warning sign, indicating that an adjustment threshold is being reached, at least for part of the howler monkey population in this forest fragment. © 2013 Wiley Periodicals, Inc.

Rangel-Negrin A.,University of Barcelona | Dias P.A.D.,University of Veracruz | Chavira R.,Institute Ciencias Medicas y Nutricion Salvador Zubiran | Canales-Espinosa D.,University of Veracruz
Hormones and Behavior | Year: 2011

The influence of social factors on the modulation of male testosterone levels has been demonstrated among several vertebrate species. In addition to sexual activity, parental care and reproductive competition affect testosterone secretion. We examined variations in testosterone levels among male black howlers (Alouatta pigra) in various social contexts. Fecal samples were collected from nine males living in five different groups in the Mexican state of Campeche. The potential for intragroup and extragroup competition varied among the groups. The number of resident males living in the groups was the only variable that significantly explained variations in testosterone levels. Males living in unimale groups had higher testosterone levels; the highest testosterone levels were recorded for males that had experienced a shift from multimale to unimale group compositions. In this species, the probability of being challenged by extragroup males and evicted from the group during immigration events increases when males live in unimale groups. Therefore, our results suggest that male black howlers respond to competition for group membership by increasing their testosterone levels. In this context, testosterone secretion represents an anticipatory response to reproductive conflicts. Therefore, although males living in unimale groups have exclusive access to females, they face higher physiological costs associated with sustaining high testosterone levels for extended time periods. © 2010 Elsevier Inc.

Rangel-Negrin A.,University of Veracruz | Flores-Escobar E.,University of Barcelona | Chavira R.,Institute Ciencias Medicas y Nutricion Salvador Zubiran | Canales-Espinosa D.,University of Veracruz | Dias P.A.D.,University of Veracruz
Primates | Year: 2014

The measurement of hormones in fecal samples allows for the noninvasive assessment of the endocrine status of free-ranging primates. However, procedures and techniques for hormone analysis in feces must be validated, both analytically and physiologically. Few studies have addressed the endocrinology of black howler monkeys (Alouatta pigra). Due to its conservation status, direct handling of individuals from this species and invasive sample collection are highly regulated, and therefore traditional methods for the validation of hormone assays, such as pharmacological challenges, are not allowed. As a consequence, sometimes studies of the fecal hormones of free-ranging black howler monkeys do not report physiological validations and therefore the biological reliability of such measurements cannot be assessed. In order to stimulate future research with this species, the present study aimed at providing methodological bases for fecal endocrine monitoring. Specifically, we compared the validity of two immunoassays (radioimmunoassays, RIA; solid-phase chemiluminescent enzyme immunoassay, SPCEI) performed with commercial kits to measure cortisol, testosterone, estradiol, and progesterone; and demonstrate how the physiological functions of these steroid hormones can be determined through non-pharmacological validations. We found no differences between the analytical validity of RIA and SPCEI assays to measure cortisol and testosterone, whereas for estradiol and progesterone RIA showed better results. Concerning the physiological validation of our assays, we demonstrated that: (1) comparisons between pre- and post-stress situations may be used to assess cortisol response, (2) comparisons between females and males may be used to assess variation in testosterone levels, and (3) comparisons between pregnant and non-pregnant females may be used to determine variation in estradiol and progesterone activity. The analytical and physiological validations that we performed demonstrate that there are currently commercial kits that allow for correct endocrine monitoring of this species, and that there are non-pharmacological alternatives to assess the biological validity of hormone measurements. © 2014, Japan Monkey Centre and Springer Japan.

Rodriguez-Flores E.,National Autonomous University of Mexico | Campuzano J.,National Autonomous University of Mexico | Aguilar D.,Institute Ciencias Medicas y Nutricion Salvador Zubiran | Hernandez-Pando R.,Institute Ciencias Medicas y Nutricion Salvador Zubiran | Espitia C.,National Autonomous University of Mexico
Tuberculosis | Year: 2012

The human pathogen Mycobacterium tuberculosis binds to a variety of host cell proteins, including those of the fibrinolytic system. These observations prompted us to study the expression of components of this system in an animal model of progressive pulmonary tuberculosis. Lung homogenates from BALB/c mice infected with M. tuberculosis H37Rv were analyzed to determine the expression and enzymatic activity of plasmin/plasminogen and tissue plasminogen activator, as well as the mRNA levels for plasminogen, tissue and urokinase plasminogen activators. Plasminogen was also detected in infected lungs with immunohistochemistry. The results show that the expression of molecules of the fibrinolytic system increased gradually over the course of the infection, peaking during the chronic phase of the disease. Furthermore, in vitro experiments showed that both plasminogen activators were specifically induced after the stimulation of spleen cells from BCG-immunized mice with M. tuberculosis proteins. Together, these results show that molecules of the fibrinolytic system are up-regulated in the chronic phase of experimental tuberculosis and suggest that the mycobacterium itself could play an important role in the overexpression of molecules of the fibrinolytic system, contributing to chronic inflammation in tuberculosis. © 2012 Elsevier Ltd. All rights reserved.

Hernandez I.V.,Institute Medicina Tropical Pedro Kouri | Ernesto Montoro Cardoso C.,Institute Medicina Tropical Pedro Kouri | Hernandez-Pando R.,Institute Ciencias Medicas y Nutricion Salvador Zubiran
Revista Cubana de Medicina Tropical | Year: 2012

Introduction: development of new antituberculosis vaccines requires the characterization of the cell-mediated immune responses induced by mycobacterial antigens. Objective: to determine the immunogenic potential of 'Mycobacterium habana' TMC-5135 when using subcutaneous vaccine in Balb/c mice. Methods: in this study, Balb/c mice were inoculated subcutaneously with live 'Mycobacterium habana' TMC-5135. The production of IFN gamma in cell suspensions obtained from the lungs, the spleen and the lymph nodes after stimulation with mycobacterial antigens Ag85b or culture filtrate antigens (CFA) was recorded. Results: the production of IFN gamma after stimulation with CFA and Ag85b was higher in mice vaccinated with 'M. habana' than in animals immunized with BCG. Conclusions: these results encourage new research on 'M. habana' as vaccinal candidate against tuberculosis.

Suarez-Dominguez E.A.,Conducta | Morales-Mavil J.E.,Conducta | Chavira R.,Institute Ciencias Medicas y Nutricion Salvador Zubiran | Boeck L.,Institute Ciencias Medicas y Nutricion Salvador Zubiran
Amphibia Reptilia | Year: 2011

Habitat perturbation due to human activities may generate numerous behavioural and physiological alterations in wild animals. In consequence, some individuals become more susceptible to diseases, while others modify their foraging behaviour or present a diminished reproductive success. In this study, we compare the daily activity pattern (DAP) and the levels of faecal glucocorticoids (fCORT) of individuals of spiny tailed iguana (Ctenosaura acanthura) found in conserved habitats, with those found in areas perturbed by human activities. Our results indicate that none of the behaviours (basking, resting, feeding, locomotion, movement and aggression) presented significant differences between habitats. Furthermore, the concentrations of fCORT were similar among individuals from both sites. We suggest that the spiny tailed iguana is a species that has adapted to perturbed areas, where it has found enough resources to survive. Our findings imply that iguanas are less sensitive to habitat degradation; additionally, these results may serve as a basis for future research aiming to describe behavioural and physiological characteristics of reptile species living in perturbed habitats. © 2011 Brill Academic Publishers.

Aguilar-Cucurachi M.A.S.,University of Veracruz | Dias P.A.D.,University of Veracruz | Rangel-Negrin A.,University of Barcelona | Chavira R.,Institute Ciencias Medicas y Nutricion Salvador Zubiran | And 2 more authors.
American Journal of Primatology | Year: 2010

Translocation-an extensively used conservation tool-is a potentially stressful event, as animals are exposed to multiple stressors and cannot predict or control the changes in their environment. Therefore, it may be expected that during a translocation program stress accumulates and social behavior changes. Here, we present data from a translocation of four adult mantled howlers (Alouatta palliata), which was conducted in southern Veracruz (Mexico). We found that stress (measured in fecal corticosterone) increased during translocation, but that the rate of both affiliative and agonistic interactions remained unchanged. Females showed higher levels of corticosterone than males throughout translocation, although no sex differences were observed in social interactions. Our findings provide a preliminary evidence for accumulation of physiological stress during translocation in primates, and may have implications for decisions concerning releasing practices. © 2010 Wiley-Liss, Inc.

PubMed | University of Veracruz and Institute Ciencias Medicas y Nutricion Salvador Zubiran
Type: Journal Article | Journal: PloS one | Year: 2014

The non-invasive monitoring of glucocorticoid hormones allows for the assessment of the physiological effects of anthropogenic disturbances on wildlife. Variation in glucocorticoid levels of the same species between protected and unprotect areas seldom has been measured, and the available evidence suggests that this relationship may depend on species-specific habitat requirements and biology. In the present study we focused on black howler monkeys (Alouatta pigra), a canopy-dwelling primate species, as a case study to evaluate the physiological consequences of living in unprotected areas, and relate them with intragroup competition and competition with extragroup individuals. From February 2006 to September 2007 we collected 371 fecal samples from 21 adults belonging to five groups (two from protected and three from unprotected areas) in Campeche, Mexico. We recorded agonistic interactions within groups and encounters with other groups (1,200 h of behavioral observations), and determined fecal glucocorticoid metabolite (FGM) concentrations with radioimmunoassays. We used linear mixed models and Akaikes information criterion to choose the best model explaining variation in FGM concentrations between protected and unprotected areas calculated from five categorical variables: habitat type (protected vs. unprotected), participation in agonistic interactions, intergroup encounters, sex and female reproductive state, and season. The best model included habitat type, the interaction between habitat type and agonism, and the interaction between habitat type and season. FGM concentrations were higher in unprotected habitats, particularly when individuals were involved in agonistic interactions; seasonal variation in FGM concentrations was only detected in protected habitats. High FGM concentrations in black howler monkeys living in unprotected habitats are associated with increased within-group food competition and probably associated with exposure to anthropogenic stressors and overall food scarcity. Because persistent high GC levels can be detrimental to health and fitness, populations living in disturbed unprotected areas may not be viable in the long-term.

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