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C Imhoff, F Giri, P Siroski, P Amavet
The heterogeneity of biotic and abiotic factors influencing fitness produce selective pressures that promote local adaptation and divergence among different populations of the same species. In order for adaptations to be maintained through evolutionary time, heritable genetic variation controlling the expression of the morphological features under selection is necessary. Here we compare morphological shape variability and size of the cephalic region of Salvator merianae specimens from undisturbed environments to those of individuals from disturbed environments, and estimated heritability for shape and size using geometric morphometric and quantitative genetics tools...
February 14, 2018: Zoology: Analysis of Complex Systems, ZACS
Rodrigo S B Gavira, Marina R Sartori, Manuel N Gontero-Fourcade, Bruna F Gomes, Augusto S Abe, Denis V Andrade
Tegu lizards ( Salvator merianae ) aestivate for up to 5 months during Brazil's winter, when they retreat to burrows and halt most activities. Dormant tegus reduce their gastrointestinal (GI) mass, which allows a substantial energy economy. This strategy, however, implies that the first post-dormancy digestion would be more costly than subsequent feeding episodes as a result of GI atrophy. To address this, we determined the postprandial metabolic response (SDA) of the first (M1), second (M2) and several (RM) feeding episodes after tegus' dormancy...
April 19, 2018: Journal of Experimental Biology
José L Escalona, Graciela L Uzcanga, Liomary M Carrasquel, José Bubis
Salivarian trypanosomes evade the host immune system by continually swapping their protective variant surface glycoprotein (VSG) coat. Given that VSGs from various trypanosome stocks exhibited cross-reactivity (Camargo et al., Vet. Parasitol. 207, 17-33, 2015), we analyzed here which components are the antigenic determinants for this cross-reaction. Soluble forms of VSGs were purified from four Venezuelan animal trypanosome isolates: TeAp-N/D1, TeAp-ElFrio01, TeAp-Mantecal01, and TeGu-Terecay323. By using the VSG soluble form from TeAp-N/D1, we found that neither the inositol-1,2-cyclic phosphate moiety of the cross-reacting determinant nor the carbohydrate chains were exclusively responsible for its cross-reactivity...
January 24, 2018: Journal of Immunoassay & Immunochemistry
Lawrence E Reeves, Kenneth L Krysko, Michael L Avery, Jennifer L Gillett-Kaufman, Akito Y Kawahara, C Roxanne Connelly, Phillip E Kaufman
The Burmese python, Python bivittatus Kuhl, is a well-established invasive species in the greater Everglades ecosystem of southern Florida, USA. Most research on its ecological impacts focuses on its role as a predator and its trophic interactions with native vertebrate species, particularly mammals. Beyond predation, there is little known about the ecological interactions between P. bivittatus and native faunal communities. It is likely that established populations of P. bivittatus in southern Florida serve as hosts for native mosquito communities...
2018: PloS One
Kelly Torralvo, Robinson Botero-Arias, William E Magnusson
On the Amazon floodplain, the main predators of black caiman (Melanosuchus niger) eggs are jaguars (Panthera onca), tegu lizards (Tupinambis teguixim), capuchin monkeys (Sapajus macrocephalus) and humans (Homo sapiens). In this study, we investigated the relationship between predator attacks on nests and incubation period, and evaluated the influence of initial predation on subsequent predation in the Mamirauá Sustainable Development Reserve. We also evaluated the influence of presence of females near the nests and manipulation of nests on the occurrence of attacks...
2017: PloS One
Ana Paula Mestre, Patricia Susana Amavet, Pablo Ariel Siroski
The genus Salvator is widely distributed throughout South America. In Argentina, the species most abundant widely distributed is Salvator merianae. Particularly in Santa Fe province, the area occupied by populations of these lizards overlaps with areas where agriculture was extended. With the aim of established baseline values for four immunologic biomarkers widely used, 36 tegu lizards were evaluated tacking into account different age classes and both sexes. Total leukocyte counts were not different between age classes...
2017: Open Veterinary Journal
Carly Young, Nicole Ravida, Michelle Curtis, Frank Mazzotti, Barbara Durrant
Of the 934 lizard species evaluated by the International Union for the Conservation of Nature (IUCN), at least one-third is threatened with extinction. However, there are no reports of semen cryopreservation efforts for lizards. Invasive Argentine black and white tegus were captured in the Florida Everglades, and sperm was collected postmortem. Initial motility score (IMS; % motile × speed of progression2 × 100), plasma membrane integrity (IPL), and acrosome integrity (IAC) were recorded. Sperm was diluted in TEST-yolk buffer with a final glycerol or dimethylsulfoxide (DMSO)concentration of 8%, 12%, or 16%, and frozen at 0...
January 1, 2017: Theriogenology
John C Murphy, Michael J Jowers, Richard M Lehtinen, Stevland P Charles, Guarino R Colli, Ayrton K Peres, Catriona R Hendry, R Alexander Pyron
Tegus of the genera Tupinambis and Salvator are the largest Neotropical lizards and the most exploited clade of Neotropical reptiles. For three decades more than 34 million tegu skins were in trade, about 1.02 million per year. The genus Tupinambis is distributed in South America east of the Andes, and currently contains four recognized species, three of which are found only in Brazil. However, the type species of the genus, T. teguixin, is known from Bolivia, Brazil, Colombia, Ecuador, French Guyana, Guyana, Peru, Suriname, Trinidad and Tobago, and Venezuela (including the Isla de Margarita)...
2016: PloS One
Laura G Schaumburg, Pablo A Siroski, Gisela L Poletta, Marta D Mudry
Environmental contaminants produce multiple adverse consequences at individual, population and ecosystem levels. High volumes of agrochemicals applied to great variety of crops, together with agricultural expansion, generate great concerns due to the impact for the environment and large risk implicated for wildlife. The lack of data on these threats is striking. The tegu lizard (Salvator merianae) is one of the species that live in environments under contaminant effects. Several characteristics allow proposing this species as a potential sentinel organism for the monitoring of pesticides in their habitat...
June 2016: Pesticide Biochemistry and Physiology
Troy Camarata, Alexis Howard, Ruth M Elsey, Sarah Raza, Alice O'Connor, Brian Beatty, Jack Conrad, Nikos Solounias, Priscilla Chow, Saima Mukta, Aleksandr Vasilyev
New nephron formation (nephrogenesis) ceases in mammals around birth and is completely absent in adults. In contrast, postembryonic nephrogenesis is well documented in the mesonephric kidneys of fishes and amphibians. The transient mesonephros in reptiles (including birds) and mammals is replaced by the metanephros during embryogenesis. Thus, one may speculate that postembryonic nephrogenesis is restricted to the mesonephric kidney. Previous reports have suggested the metanephros of non-avian reptiles (hereafter reptiles) may continually form nephrons throughout life...
2016: PloS One
Glenn J Tattersall
Extant endotherms have high rates of metabolism, elevated body temperatures, usually tight control over body temperature, and a reasonable scope for further increases in metabolism through locomotor activity. Vertebrate ectotherms, on the other hand, rely on behavioural thermoregulation and cardiovascular adjustments to facilitate warming, and generally lack specific biochemical and cellular mechanisms for sustained, elevated metabolism. Nevertheless, the ancestral condition to endothermy is thought to resemble that of many extant reptiles, which raises the question of the origins and selection pressures relevant to the transitional state...
October 2016: Zoology: Analysis of Complex Systems, ZACS
G R Leal, P P Serafini, I Simão-Neto, R J Ladle, M A Efe
Basic information on natural history is crucial for assessing the viability of populations, but is often lacking for many species of conservation concern. One such species is the White-tailed Tropicbird, Phaethon lepturus (Mathews, 1915). Here, we address this shortfall by providing detailed information on reproductive biology, distribution and threats on the Fernando de Noronha archipelago, Brazil - the largest colony of P. lepturus in the South Atlantic. We assessed reproduction from August 2011 to January 2012 by monitoring tropicbird nests and their contents...
April 19, 2016: Brazilian Journal of Biology, Revista Brasleira de Biologia
Lucas Francisco R do Nascimento, Lilian Cristina da Silveira, Laura Gabriela Nisembaum, Alison Colquhoun, Agusto S Abe, Carlos Alberto Mandarim-de-Lacerda, Silvia Cristina R de Souza
Seasonal plasticity in the small intestine of neonatal tegu lizards was investigated using morphometry and analysis of enzymes involved in supplying energy to the intestinal tissue. In the autumn, the intestinal mass (Mi) was 1.0% of body mass and the scaling exponent b=0.92 indicated that Mi was larger in smaller neonates. During arousal from dormancy Mi was 23% smaller; later in spring, Mi increased 60% in relation to the autumn and the exponent b=0.14 indicated that the recovery was disproportionate in smaller tegus...
May 2016: Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology
Glenn J Tattersall, Cleo A C Leite, Colin E Sanders, Viviana Cadena, Denis V Andrade, Augusto S Abe, William K Milsom
With some notable exceptions, small ectothermic vertebrates are incapable of endogenously sustaining a body temperature substantially above ambient temperature. This view was challenged by our observations of nighttime body temperatures sustained well above ambient (up to 10°C) during the reproductive season in tegu lizards (~2 kg). This led us to hypothesize that tegus have an enhanced capacity to augment heat production and heat conservation. Increased metabolic rates and decreased thermal conductance are the same mechanisms involved in body temperature regulation in those vertebrates traditionally acknowledged as "true endotherms": the birds and mammals...
January 2016: Science Advances
Tatiane A Paixão, Fernanda M Coura, Marcelo C C Malta, Herlandes P Tinoco, Angela T Pessanha, Felipe L Pereira, Carlos A G Leal, Marcos B Heinemann, Henrique C P Figueiredo, Renato L Santos
The draft genome sequences of two Salmonella enterica serotype Infantis isolates are reported here. One of the strains was isolated from a western lowland gorilla (Gorilla gorilla gorilla) with colitis. The second strain was isolated from a reptile that inhabited the same premises. Whole-genome sequencing demonstrated that these isolates were not clonal.
2016: Genome Announcements
Lucas A Zena, Valter Dantonio, Luciane H Gargaglioni, Denis V Andrade, Augusto S Abe, Kênia C Bícego
Baroreflex regulation of blood pressure is important for maintaining appropriate tissue perfusion. Although temperature affects heart rate (fH) reflex regulation in some reptiles and toads, no data are available on the influence of temperature-independent metabolic states on baroreflex. The South American tegu lizard Salvator merianae exhibits a clear seasonal cycle of activity decreasing fH along with winter metabolic downregulation, independent of body temperature. Through pharmacological interventions (phenylephrine and sodium nitroprusside), the baroreflex control of fH was studied at ∼ 25 °C in spring-summer- and winter-acclimated tegus...
March 2016: Journal of Experimental Biology
Nicolas Rodolfo Cecchetto, Sergio Naretto
Body temperature is a key factor in physiological processes, influencing lizard performances; and life history traits are expected to generate variability of thermal preferences in different individuals. Gender, body size and reproductive condition may impose specific requirements on preferred body temperatures. If these three factors have different physiological functions and thermal requirements, then the preferred temperature may represent a compromise that optimizes these physiological functions. Therefore, the body temperatures that lizards select in a controlled environment may reflect a temperature that maximizes their physiological needs...
October 2015: Journal of Thermal Biology
E Sánchez, T Perrone, G Recchimuzzi, I Cardozo, N Biteau, P M Aso, A Mijares, T Baltz, D Berthier, L Balzano-Nogueira, M I Gonzatti
BACKGROUND: Livestock trypanosomoses, caused by three species of the Trypanozoon subgenus, Trypanosoma brucei brucei, T. evansi and T. equiperdum is widely distributed throughout the world and constitutes an important limitation for the production of animal protein. T. evansi and T. equiperdum are morphologically indistinguishable parasites that evolved from a common ancestor but acquired important biological differences, including host range, mode of transmission, distribution, clinical symptoms and pathogenicity...
2015: Parasites & Vectors
Joanna Piercy, Kip Rogers, Michelle Reichert, Denis V Andrade, Augusto S Abe, Glenn J Tattersall, William K Milsom
The present study determined whether EEG and/or EMG recordings could be used to reliably define activity states in the Brazilian black and white tegu lizard (Tupinambis merianae) and then examined the interactive effects of temperature and activity states on strategies for matching O2 supply and demand. In a first series of experiments, the rate of oxygen consumption (VO2), breathing frequency (fR), heart rate (fH), and EEG and EMG (neck muscle) activity were measured in different sleep/wake states (sleeping, awake but quiet, alert, or moving)...
December 2015: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
Colin E Sanders, Glenn J Tattersall, Michelle Reichert, Denis V Andrade, Augusto S Abe, William K Milsom
This study was designed to determine the manner in which metabolism is suppressed during dormancy in black and white tegu lizards (Tupinambis merianae). To this end, heart rate (fH), respiration rate (fR), and deep body temperature (Tb) were continuously monitored in outdoor enclosures by radio-telemetry for nine months. There was a continuous decline in nighttime breathing and heart rate, at constant Tb, throughout the late summer and fall suggestive of an active metabolic suppression that developed progressively at night preceding the entrance into dormancy...
December 2015: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
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