Search

Made available in DSpace on 2020-12-10T17:37:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-07-21 Direccion General de Asuntos del Personal Academico, Universidad Nacional Autonoma de Mexico Consejo Nacional de Ciencia y Tecnologia Conselho Nacional de Pesquisa e Desenvolvimento Tecnologico Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Sickness triggers a series of behavioral and physiological processes collectively known as acute phase response (APR). Bats are known as reservoirs of a broad variety of pathogens and the physiological changes resulting from APR activation have been tested predominantly during the resting phase (daytime) in several species exposed to lipopolysaccharide (LPS). In contrast, behavioral consequences of sickness for bats and other wild mammals have received less attention. We examined the physiological and behavioral consequences of APR activation in a fruit-eating bat (Carollia perspicillata) challenged with LPS during the active phase (nighttime). We measured changes in food intake, body mass, body temperature, total white blood cell counts, and the neutrophil/lymphocyte ratio (N/L). No fever and leukocytosis were observed in bats injected with LPS, but food intake decreased, bats lost body mass and their N/L ratio increased. The effect of LPS on daily energy balance is remarkable and, along with the increase in N/L ratio, it is assumed to be beneficial to fight disease. On the basis of our findings and those with other bats, it is probable that the physiological and behavioral components of the immune response to LPS follow circadian rhythms, but a formal test of this hypothesis is warranted. Univ Estadual Paulista, Dept Biodiversidade, Inst Biociencias, Rio Claro, SP, Brazil Univ Nacl Autonoma Mexico, Inst Biol, Estn Biol Chamela, San Patricio, Jalisco, Mexico Univ Estadual Paulista, Dept Biodiversidade, Inst Biociencias, Rio Claro, SP, Brazil Direccion General de Asuntos del Personal Academico, Universidad Nacional Autonoma de Mexico: 814-2018 Consejo Nacional de Ciencia y Tecnologia: 490586/2013-9 Conselho Nacional de Pesquisa e Desenvolvimento Tecnologico: 43486 Conselho Nacional de Pesquisa e Desenvolvimento Tecnologico: 490586/20139 FAPESP: 2014/17607-4 FAPESP: 2017-17607-6

Made available in DSpace on 2022-04-29T08:39:52Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-01-01 Lead (Pb) is one of the most common metals found in ecosystems in elevated concentrations derived mainly from anthropogenic activities. Pb toxicity is of special concern in birds due to its capacity for bioaccumulation in the liver, bones, and kidneys causing physiological disruptions. Such disruptions can be lethal in a few days after Pb acute intoxication and they are associated with several million deaths of birds. Moreover, Pb may work as an immunosuppressant as it affects the cell-mediated and humoral immune responses, including components of the acute-phase response (APR). We (1) examined the effects of Pb contamination on the innate immune system, body mass, and food intake of Japanese quails (Coturnix coturnix japonica), and (2) evaluated the effects of Pb on its APR after exposing the animals to Pb acetate in drinkable water during 7 days. We found that Pb contamination increased the number of circulating white blood cells (WBCs), but no effect was found on body mass, food intake, the heterophil/lymphocyte (H/L) ratio, and haptoglobin (Hp) concentration. When Pb-exposed birds were injected with lipopolysaccharide from Escherichia coli to activate the APR, they had a negative body mass ratio, reduced food intake, and increased the number of WBCs, the H/L ratio, and the Hp concentration. We conclude that Pb exposure at this dose did not affect baseline values of the constitutive response and that it did not affect the APR of quails, but commend for further studies testing the effect of different Pb doses. Departamento de Biodiversidade Instituto de Biociências Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP), São Paulo Centro de Estudos Ambientais Universidade Estadual Paulista (UNESP), São Paulo Estación de Biología Chamela Instituto de Biología Universidad Nacional Autónoma de México, Jalisco Departamento de Biodiversidade Instituto de Biociências Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP), São Paulo Centro de Estudos Ambientais Universidade Estadual Paulista (UNESP), São Paulo

When snakes digest large meals, heart rate is accelerated by withdrawal of vagal tone and an increased non-adrenergic-non-cholinergic tone that seems to stem from circulating blood-borne factors exerting positive chronotropic effects. To investigate whether this tonic elevation of heart rate impairs the ability for autonomic regulation of heart during digestion, we characterised heart rate responses to pharmacological manipulation of blood pressure in the snake Boa constrictor through serial injections of sodium nitroprusside and phenylephrine. Both fasting and digesting snakes responded with a robust tachycardia to hypotension induced by sodium nitroprusside, with digesting snakes attaining higher maximal heart rates than fasting snakes. Both fasting and digesting snakes exhibited small reductions of the cardiac chronotropic response to hypertension, induced by injection of phenylephrine. All heart rate changes were abolished by autonomic blockade with the combination of atropine and propranolol. The digesting snakes retained the capacity for compensatory heart rate responses to hypotension, despite their higher resting values, and the upward shift of the barostatic response curve enables snakes to maintain the cardiac limb of barostatic regulation for blood pressure regulation.

Habitat fragmentation could alter ecological traits including species trophic habits. Here, we used carbon and nitrogen stable isotope ratios to establish differences in isotopic niche width and food resource use between forest fragments and the continuous forest for the phyllostomid frugivorous bat Artibeus lituratus. Using mist nests, we captured bats from two forest fragments and two sites in continuous forest, and sampled from each individual captured three body tissues with contrasting turnover rates (skin, muscle, and liver). Samples were collected between February and March (austral summer) and between August and September (austral winter). In addition, in each sampling site and season we collected potential food resources (fruits and insects) consumed by our A. lituratus. Our findings indicate that A. lituratus had a predominantly omnivorous diet, with high consumption of insects during summer in forest fragments. The increasing consumption of insects in these fragments seems to have led to a wider isotopic niche, in relation to the continuous forest. Because A. lituratus is typically a seed disperser, changes in trophic habits in the forest fragments from frugivory to insectivory may diminish their role in forest regeneration. Abstract in Portuguese is available with online material.

Made available in DSpace on 2022-04-28T19:45:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 In the Neotropical region, euphonias (Euphonia spp., Fringillidae) are the quintessential example of specialized bird frugivores, making the bulk of feeding visits to certain mistletoes (Phoradendron spp., Santalaceae) and epiphytes in the genus Rhipsalis (Cactaceae), whose fruits have high water and low sugar and protein concentrations. Surprisingly, a mechanistic explanation for such specialized, otherwise rare, relationships is lacking. Using captive birds and artificial diets, we contrasted euphonias with frugivorous tanagers in the genus Thraupis (Thraupidae), which rarely eats Rhipsalis fruits, to test the hypothesis that the digestive capacity of euphonias entails them to exploit such low-energy fruits. We expected that compensatory feeding in response to decreasing energy density would occur only in euphonias, whose higher reliance on fruits would entail a lower nitrogen requirement than the tanagers. Euphonias and tanagers were both able to compensate energy intake as sugar density decreased, and both species had the same mass-corrected energy intake at any given sugar concentration. Similarly, euphonias and tanagers did not differ in mass-corrected maintenance nitrogen requirement. Therefore, the physiological traits we investigated do not explain euphonias' specialization on Rhipsalis fruits. The fast rates of fruit passage typical of specialized avian frugivores as euphonias that entail the processing of a large volume of fruits and the putative better abilities of such birds to deal with secondary compounds likely present in Rhipsalis fruits are other possible mechanisms that should be considered in future studies to unveil the mechanisms underlying the intriguing specialized relationships between euphonias and certain fruits. Programa de Pós-graduação em Ecologia Evolução e Biodiversidade Univ. Estadual Paulista Depto de Biodiversidade Univ. Estadual Paulista Pós-graduação em Zoologia Univ. Estadual Paulista Estación de Biología Chamela Inst. de Biología Univ. Nacional Autónoma de México Programa de Pós-graduação em Ecologia Evolução e Biodiversidade Univ. Estadual Paulista Depto de Biodiversidade Univ. Estadual Paulista Pós-graduação em Zoologia Univ. Estadual Paulista

In this study, we aimed to evaluate the influence of daily repeated menthol treatments on body mass and thermoregulatory effectors in Wistar rats, considering that menthol is a transient receptor potential melastatin 8 channel agonist that mimics cold sensation and activates thermoregulatory cold-defense mechanisms in mammals, promoting hyperthermia and increasing energy expenditure, and has been suggested as an anti-obesity drug. Male Wistar rats were topically treated with 5% menthol for 3 or 9 consecutive days while body mass, food intake, abdominal temperature, metabolism, cutaneous vasoconstriction, and thermal preference were measured. Menthol promoted hyperthermia on all days of treatment, due to an increase in metabolism and cutaneous vasoconstriction, without affecting food intake, resulting in less mass gain in menthol-hyperthermic animals. As the treatment progressed, the menthol-induced increases in metabolism and hyperthermia were attenuated but not abolished. Moreover, cutaneous vasoconstriction was potentiated, and an increase in the warmth-seeking behavior was induced. Taken together, the results suggest that, although changes occur in thermoeffector recruitment during the course of short-term treatment, menthol is a promising drug to prevent body mass gain. NEW & NOTEWORTHY Menthol produces a persistent increase in energy expenditure, with limited compensatory thermoregulatory adaptations and, most unexpectedly, without affecting food intake. Thus short-term treatment with menthol results in less mass gain in treated animals compared with controls. Our results suggest that menthol is a promising drug for the prevention of obesity.

Flying mammals present unique intestinal adaptations, such as lower intestinal surface area than nonflying mammals, and they compensate for this with higher paracellular absorption of glucose. There is no consensus about the mechanistic bases for this physiological phenomenon. The surface area of the small intestine is a key determinant of the absorptive capacity by both the transcellular and the paracellular pathways; thus, information about intestinal surface area and micro‐anatomical structure can help explain differences among species in absorptive capacity. In order to elucidate a possible mechanism for the high paracellular nutrient absorption in bats, we performed a comparative analysis of intestinal villi architecture and enterocyte size and number in microchiropterans and rodents. We collected data from intestines of six bat species and five rodent species using hematoxylin and eosin staining and histological measurements. For the analysis we added measurements from published studies employing similar methodology, making in total a comparison of nine species each of rodents and bats. Bats presented shorter intestines than rodents. After correction for body size differences, bats had ~41% less nominal surface area (NSA) than rodents. Villous enhancement of surface area (SEF) was ~64% greater in bats than in rodents, mainly because of longer villi and a greater density of villi in bat intestines. Both taxa exhibited similar enterocyte diameter. Bats exceeded rodents by ~103% in enterocyte density per cm2 NSA, but they do not significantly differ in total number of enterocytes per whole animal. In addition, there is a correlation between SEF and clearance per cm2 NSA of L‐arabinose, a nonactively transported paracellular probe. We infer that an increased enterocyte density per cm2 NSA corresponds to increased density of tight junctions per cm2 NSA, which provides a partial mechanistic explanation for understanding the high paracellular absorption observed in bats compared to nonflying mammals. Fil: Brun, Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina. University of Wisconsin; Estados Unidos Fil: Fernández Marinone, Guido. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia; Argentina Fil: Price, Edwin R.. University of North Texas; Estados Unidos Fil: Nell, Lucas A.. University of Wisconsin; Estados Unidos Fil: Simões, Beatriz M. V.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Castellar, Alexandre. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Gontero Fourcade, Manuel Nicolas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia; Argentina Fil: Cruz-Neto, Ariovaldo P.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Karasov, William. University of Wisconsin; Estados Unidos Fil: Caviedes Vidal, Enrique Juan Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia; Argentina

Made available in DSpace on 2019-10-04T12:14:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-07-01 Brazilian State Funding Agency of Federal District to EMV State Funding Agency of Sao Paulo Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fragmented habitats generally harbour small populations that are potentially more prone to local extinctions caused by biotic factors such as parasites. We evaluated the effects of botflies (Cuterebra apicalis) on naturally fragmented populations of the gracile mouse opossum (Gracilinanus agilis). We examined how sex, food supplementation experiment, season and daily climatic variables affected body condition and haemoglobin concentration in animals that were parasitized or not by botflies. Although parasitism did not affect body condition, haemoglobin concentrations were lower in parasitized animals. Among the non-parasitized individuals, haemoglobin concentration increased with the increase of maximum temperature and the decrease of relative humidity, a climatic pattern found at the peak of the dry season. However, among parasitized animals, the opposite relationship between haemoglobin concentration and relative humidity occurred, as a consequence of parasite-induced anaemia interacting with dehydration as an additional stressor. We conclude that it is critical to assess how climate affects animal health (through blood parameters) to understand the population consequences of parasitism on the survival of individuals and hence of small population viability. Univ Brasilia, Dept Ecol, Lab Ecol Vertebrados, Inst Ciencias Biol, BR-70919900 Brasilia, DF, Brazil Univ Estadual Paulista, Inst Biociencias Rio Claro, Ave 24A 1515 Bela Vista, BR-13506900 Rio Claro, SP, Brazil Univ Toronto Scarborough, Dept Biol Sci, Ctr Neurobiol Stress, Toronto, ON M1C 1A4, Canada Univ Estadual Paulista, Inst Biociencias Rio Claro, Ave 24A 1515 Bela Vista, BR-13506900 Rio Claro, SP, Brazil Brazilian State Funding Agency of Federal District to EMV: FAPDF - 193.000.914/2015 State Funding Agency of Sao Paulo: FAPESP 2014/16320-7 CNPq: 308992/2013-0

Screening of 533 bats for influenza A viruses showed subtype HL18NL11 in intestines of 2 great fruit-eating bats (Artibeus lituratus). High concentrations suggested fecal shedding. Genomic characterizations revealed conservation of viral genes across different host species, countries, and sampling years, suggesting a conserved cellular receptor and wide-ranging occurrence of bat influenza A viruses.

Made available in DSpace on 2021-06-25T12:33:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Ruthenium red (RR) is a non-selective antagonist of the temperature-sensitive Transient Receptor Potential (TRP) channels and it is an important pharmacological tool in thermoregulatory research. However, the effect of RR on thermoeffector activity is not well established. Here we evaluated the effect of RR on cold-defense thermoeffectors induced by menthol, an agonist of the cold-sensitive TRPM8 channel. Adult male Wistar rats were used. Epidermal treatment with menthol raised deep body temperature due to an increase in oxygen consumption (an index of thermogenesis), a reduction in heat loss index (an index of cutaneous vasoconstriction), and an induction in warmth-seeking behavior in a two-temperature choice apparatus. Pretreatment with RR attenuated the menthol-induced increase in deep body temperature and oxygen consumption, but it did not affect heat loss index and warmth-seeking behavior. To stimulate brown adipose tissue thermogenesis, rats were treated with CL 316,243, a potent and selective beta 3-adrenoceptor agonist. CL 316,243 increased deep body temperature, which was attenuated by RR pretreatment. We conclude that RR reduces brown adipose tissue thermogenesis induced by menthol and CL 316,243, independent of effects at the thermal sensor level (i.e., TRPM8). Univ Fed ABC, Grad Program Neurosci & Cognit, Sao Bernardo Do Campo, SP, Brazil Univ Fed ABC, Nat & Humanities Sci Ctr, Rua Arcturus 03, BR-09606 Sao Bernardo Do Campo, SP, Brazil Sao Paulo State Univ, Biosci Inst, Dept Zool, Rio Claro, SP, Brazil Sao Paulo State Univ, Biosci Inst, Dept Zool, Rio Claro, SP, Brazil CNPq: 449102/2014-9 FAPESP: 2015/02991-0 FAPESP: 2015/23426-9 FAPESP: 2013/25503-5

Bats are notorious reservoirs of genetically-diverse and high-profile pathogens, and are playing crucial roles in the emergence and re-emergence of viruses, both in human and in animals. In this report, we identified and characterized previously unknown and diverse genetic clusters of bat coronaviruses in the Atlantic Forest Biome, Brazil. These results highlight the virus richness of bats and their possible roles in the public health., Highlights • We describe the circulation of CoV lineages, 13 α-CoV and two β-CoV in AFB bats. • Coronaviruses were detected in 15 bat samples from eight bat species (50% positivity). • A cluster of α-CoVs were detected in Sturnira bat that grouped with α-CoVs lineage-1. • We identified two distinct β-CoV that clustered within MERS-CoV containing lineage C. • Results highlight the virus richness of bats and their possible roles in the public health.

Physiological concepts and tools can help us to understand why organisms and populations respond to habitat fragmentation in the way they do, and allow us to determine the mechanisms or individual characteristics underlying this differential sensitivity. Here, we examine food intake, relative medullary thickness and distribution/expression of water channel aquaporin-1 in three species of South American rodents that have been reported to have different levels of tolerance to habitat fragmentation (Akodon montensis, Oligoryzomys nigripes, and Euryoryzomys russatus), using a classic water deprivation experiment to assess their abilities to cope with water shortage. We believe the mechanisms underlying this differential sensitivity are related to the organisms' capacities to maintain water balance, and therefore the species more tolerant to habitat fragmentation (A. montensis and O. nigripes) should have a higher capacity to maintain water balance. We found that A. montensis and O. nigripes were more tolerant to water deprivation than E. russatus, and this difference appears to be unrelated to differences in food ingestion rate. O. nigripes showed the highest values for RMT, followed by A. montensis and E. russatus. However all species showed RMT values that were 2.2% to 14.1% below the lower prediction limit when compared to other rodents through allometric relationships. Water deprivation seems to trigger changes in the distribution of aquaporin-1, mostly for O. nigripes and E. russatus, which may contribute to water balance maintenance. Our data suggest that these intrinsic physiological differences among these species could provide a mechanism for their differential tolerance of habitat fragmentation. J. Exp. Zool. 323A: 731-744, 2015. © 2015 Wiley Periodicals, Inc.

The acute phase response (APR) is the first line of defense of the vertebrate immune system against pathogens. Mounting an immune response is believed to be energetically costly but direct measures of metabolic rate during immune challenges contradict this assumption. The energetic cost of APR for birds is higher than for rodents, suggesting that this response is less expensive for mammals. However, the particularly large increase in metabolic rate after APR activation for a piscivorous bat (Myotis vivesi) suggests that immune response might be unusually costly for bats. Here we quantified the energetic cost and body mass change associated with APR for the nectarivorous Pallas’s long-tongued bat (Glossophaga soricina). Activation of the APR resulted in a short-term decrease in body mass and an increase in resting metabolic rate (RMR) with a total energy cost of only 2% of the total energy expenditure estimated for G. soricina. This increase in RMR was far from the large increase measured for piscivorous bats; rather, it was similar to the highest values reported for birds. Overall, our results suggest that the costs of APR for bats may vary interspecifically. Measurement of the energy cost of vertebrate immune response is limited to a few species and further work is warranted to evaluate its significance for an animal’s energy budget.

Studies on birds have led to the hypothesis that increased intestinal absorption between enterocytes (paracellular) evolved as a compensation for smaller intestinal size in fliers, which was perhaps selected to minimize the mass of digesta carried. This hypothesis predicts that bats will also exhibit relatively reduced intestinal size and high paracellular absorption, compared with nonflying mammals. Published studies on three bat species indicate relatively high paracellular absorption. One mechanism for increasing paracellular absorption per cm2 small intestine (SI) is increased number of tight junctions (TJs) across which paracellular absorption occurs. To our knowledge, we provide the first comparative analysis of enterocyte size and number in flying and nonflying mammals. Intestines of insectivorous bats Tadarida brasiliensis were compared with Mus musculus using hematoxylin and eosin staining method. Bats had shorter and narrower SIs than mice, and after correction for body size difference by normalizing to mass3/4, the bats had 40% less nominal surface area than the mouse, as predicted. Villous enhancement of surface area was 90% greater in the bat than in the mouse, mainly because of longer villi and a greater density of villi in bat intestines. Bat and mouse were similar in enterocyte diameter. Bats exceeded mice by 54.4% in villous area per cm length SI and by 95% in number of enterocytes per cm2 of the nominal surface area of the SI. Therefore, an increased density of TJs per cm2 SI may be a mechanistic explanation that helps to understand the high paracellular absorption observed in bats compared to nonflying mammals.

Made available in DSpace on 2022-04-29T07:25:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-09-01 Previous bat aerodynamic power models are refined by (1) varying the value of wing profile drag with lift coefficient, which varies with both flight speed and Reynolds number, (2) allowing for the aerodynamic cleanliness of head, body, ears and tail in calculating parasitic drag values at various speeds and according to airframe type, (3) incorporating models of wingbeat amplitude and frequency in the power calculations, and, (4) upgrading the allometric, phylogenetically corrected relationship between basal metabolic rate and body mass using data from 98 bat species. The fidelity of the aerodynamic power model is assessed using published wind tunnel data on a bat in steady glide. By comparing empirical published metabolic power (Pmet) values with values derived using the new aerodynamic model, we update estimates of inflight musculoskeletal mechanical efficiency (g) for the airframes of eight bat species at steady level flight speeds. Furthermore, we calculate the increase in g at high speeds. The bats assessed range in body mass from 0.01 to 1 kg, and the comparison covers the speed range normally used by free-flying bats during their excursions. At their best endurance flight speeds (Vend), g — 1.52 Ln (mbat) +11.44 (%). At speeds > Vend, η — η@Vend+ 1.3 (V— Vend) (%). These equations yield accurate Pmet estimates for flight speeds within the range used for the steady level flight. Department of Parks and Wildlife Government of Western Australia Department of Zoology Universidade Estadual Paulista, Rio Claro CP199 Department of Zoology Universidade Estadual Paulista, Rio Claro CP199

Made available in DSpace on 2022-04-28T19:04:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-12-01 We present empirical data on flight speed for 30 species of Australian bats representing seven families. These data show five characteristic level flight speeds: ‘minimum’ (Vmin), ‘best efficiency’ (Veff), ‘most common’ (Vmode), ‘maximum cruise’ (Vmcr) and ‘maximum spurt’ (Vmsp). Next, we calculate Vmin, Veff, ‘maximum aerobic’ (Vae), ‘sustainable anaerobic’ (Vsan) and ‘maximum anaerobic’ (Vman) flight speeds using a published quasi-steady model. Model predictions were within 0.5 m s−1 of the empirical values for all five characteristic speeds given adequate samples. Model fidelity was cross-checked using flight speed data published for other Old and New World species. Bat Call WA Pty Ltd, 43 Murray Drive, 6025 Department of Parks and Wildlife, PO Box 51 Department of Zoology Universidade Estadual Paulista Department of Zoology Universidade Estadual Paulista

We studied patterns in the use of space for foraging and roosting by two frugivorous bat species in a five-year-old restored Atlantic forest located in a fragmented landscape in southeastern Brazil. Ten individuals of Carollia perspicillata and eleven individuals of Artibeus lituratus were monitored through radio-telemetry in five sampling sessions. Each session lasted 3–8 days for each individual, with an average of 25.4 ± 10 locations for each C . perspicillata individual and 19 ± 4.4 for each A . lituratus individual. We described an average range of 124.4 ha and an average commuting distance of 1158.8 m for A . lituratus and an average range and commuting distance of 32 ha and 489 m, respectively, for C . perspicillata . We demonstrated a consistent pattern in habitat use and movements for both studied species, where they strictly used forests (restored or not) for day roosting, roosting in the foliage of trees located only in secondary forest remnants and restored areas, while restored areas were their main feeding habitat. We demonstrate that newly restored forests can be readily incorporated as foraging and roosting habitats by these species, and that C . perspicillata alters its roosting behavior in relation to preferred food availability. These results, when combined with data on the diet of the studied species, show consistent evidence of the potential that bats have to improve species diversity of anthropogenic plantings with their own natural seed dispersal.

Made available in DSpace on 2018-11-26T16:19:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-01-01 US-Israel Binational National Science Foundation Blaustein Postdoctoral Fellowship VATAT fellowship from the Council of Higher Education Graduate Program of the State University of sao Paulo (PROPG - UNESP) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Life in deserts is challenging for bats because of their relatively high energy and water requirements; nevertheless bats thrive in desert environments. We postulated that bats from desert environments have lower metabolic rates (MR) and total evaporative water loss (TEWL) than their mesic counterparts. To test this idea, we measured MR and TEWL of four species of bats, which inhabit the Negev desert in Israel, one species mainly restricted to hyper-arid deserts (Otonycteris hemprichii), two species from semi-desert areas (Eptesicus bottae and Plecotus christii), and one widespread species (Pipistrellus kuhlii). We also measured separately, in the same individuals, the two components of TEWL, respiratory water loss (RWL) and cutaneous evaporative water loss (CEWL), using a mask. In all the species, MR and TEWL were significantly reduced during torpor, the latter being a consequence of reductions in both RWL and CEWL. Then, we evaluated whether MR and TEWL in bats differ according to their geographic distributions, and whether those rates change with T-a and the use of torpor. We did not find significant differences in MR among species, but we found that TEWL was lowest in the species restricted to desert habitats, intermediate in the semi-desert dwelling species, and highest in the widespread species, perhaps a consequence of adaptation to life in deserts. Our results were supported by a subsequent analysis of data collected from the literature on rates of TEWL for 35 bat species from desert and mesic habitats. (c) 2015 Elsevier Inc. All rights reserved. Ben Gurion Univ Negev, Jacob Blaustein Inst Desert Res, Mitrani Dept Desert Ecol, IL-8499000 Midreshet Ben Gurion, Israel Ohio State Univ, Dept Evolut Ecol & Organismal Biol, Aronoff Lab, Columbus, OH 43210 USA Univ Estadual Paulista, Dept Zool, IB, BR-13506900 Sao Paulo, Brazil Univ Estadual Paulista, Dept Zool, IB, BR-13506900 Sao Paulo, Brazil US-Israel Binational National Science Foundation: 2008469 FAPESP: 08/57687-0

We examine here the thermal physiology of the ash-grey mouse, as there is a paucity of data to explain how Australian rodents meet thermoregulatory demands. Most ash-grey mice remained normothermic over a range of ambient temperatures (10 °C to 30 °C), although they became hyperthermic at high ambient temperatures. One individual entered torpor at ambient temperatures of 20 °C and 25 °C, with minimal body temperatures of 24.5 °C and 28.4 °C respectively, before spontaneously arousing. This is the first evidence of torpor use by an Australian murine rodent. Our data suggest that although ash-grey mice have the physiological ability to use torpor, it is used rarely, presumably due to other behavioural and physiological adaptations. Their higher-than-expected basal metabolic rate (1.56±0.25 mL O(2)g(-1) h(-1)) indicates that ash-grey mice do not have a frugal approach to energy expenditure. Other standard physiological variables were typical of a generalised rodent. A readily-available omnivorous diet, nocturnal activity, semi-fossorial habit and social behaviour presumably allow a high energy lifestyle. A reluctance to use torpor, despite an apparent physiological ability to do so, supports the idea that the use of torpor reflects a net balance between the costs and benefits of a heterothermic thermoregulatory strategy.

This study evaluated the thermogenic capacity of three species of fruit-eating phyllostomid bats (Carollia perspicillata, Sturnira lilium and Artibeus lituratus) during the dry-cool and wet-warm seasons, by measuring changes in body mass, basal metabolic rate (BMR), maximal metabolic rate (MMR), nonshivering thermogenesis and shivering thermogenesis. Body mass was lower, on average, during the dry-cool season and all species of fruit-eating bats showed an increase in oxygen consumption after noradrenaline injection and after exposure to a He–O2 atmosphere. However, the magnitude of this increase was similar in both seasons. BMR also did not vary between seasons. Although, our results showed for the first time that all three species studied were able to increase thermogenesis by both nonshivering and shivering thermogenesis, we did not find significant differences in any thermoregulatory variable measured when comparing data from the two different seasons. Probably the difference in the mean and variance of the temperature profile between seasons were not strong enough to alter the thermogenic capacity of these species. Furthermore, the use of alternative physiological (torpor) or behavioral (huddling) strategies might have alleviated the need to trigger energetic-costly thermogenic responses.

Frugivorous bats can be attracted with essential oils from ripe chiropterochoric fruit. We evaluated the efficiency of these oils to attract bats in degraded areas within the Atlantic Rain Forest, particularly pasture and agricultural land. We hypothesized that induction units (IUs), each containing a rubber septum impregnated with oil, would have more bat activity than their respective control units (CUs; without the oil). To test this hypothesis we monitored bat flight activity with night-vision infrared visors in eight IU and CU from August 2006 to July 2007. We also verified the probability of arrival of chiropterochoric seeds by analyzing the diet of bats captured in a neighboring forest area. Our initial hypothesis that units with odor would lead to greater bat activity was confirmed. Results indicated a rich community of fruit-eating bats, and dietary analysis revealed a huge potential for dispersion of a vast amount of seeds from different plant species at the IU. Although our study does not reveal with certainty which bat species are attracted to the oil, the flying patterns coincide with those described for the foraging behavior of fruit-eating phyllostomids. Furthermore, the fact that the bats spend more time flying around the odor source compared to flying time around CU suggest an increase in seed rain. Taken together, these results suggest that the use of essential oils from chiropterochoric fruits induces a qualitative and quantitative increase in seed dispersal in areas that otherwise would not be frequently visited by frugivorous bats.

Measures of traits are the basis of functional biological diversity. Numerous works consider mean species-level measures of traits while ignoring individual variance within species. However, there is a large amount of variation within species and it is increasingly apparent that it is important to consider trait variation not only between species, but also within species. Mammals are an interesting group for investigating trait-based approaches because they play diverse and important ecological functions (e.g., pollination, seed dispersal, predation, grazing) that are correlated with functional traits. Here we compile a data set comprising morphological and life history information of 279 mammal species from 39,850 individuals of 388 populations ranging from −5.83 to −29.75 decimal degrees of latitude and −34.82 to −56.73 decimal degrees of longitude in the Atlantic forest of South America. We present trait information from 16,840 individuals of 181 species of non-volant mammals (Rodentia, Didelphimorphia, Carnivora, Primates, Cingulata, Artiodactyla, Pilosa, Lagomorpha, Perissodactyla) and from 23,010 individuals of 98 species of volant mammals (Chiroptera). The traits reported include body mass, age, sex, reproductive stage, as well as the geographic coordinates of sampling for all taxa. Moreover, we gathered information on forearm length for bats and body length and tail length for rodents and marsupials. No copyright restrictions are associated with the use of this data set. Please cite this data paper when the data are used in publications. We also request that researchers and teachers inform us of how they are using the data. Fil: Gonçalves, Fernando. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Bovendorp, Ricardo S.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Beca, Gabrielle. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Bello, Carolina. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Costa Pereira, Raul. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Muylaert, Renata L.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Rodarte, Raisa R.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Villar, Nacho. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Souza, Rafael. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Graipel, Maurício E.. Universidade Federal de Santa Catarina; Brasil Fil: Cherem, Jorge J.. Caipora Cooperativa, Florianopolis; Brasil Fil: Faria, Deborah. Universidade Estadual de Santa Cruz; Brasil Fil: Baumgarten, Julio. Universidade Estadual de Santa Cruz; Brasil Fil: Alvarez, Martín R.. Universidade Estadual de Santa Cruz; Brasil Fil: Vieira, Emerson M.. Universidade do Brasília; Brasil Fil: Cáceres, Nilton. Universidade Federal de Santa María. Santa María; Brasil Fil: Pardini, Renata. Universidade de Sao Paulo; Brasil Fil: Leite, Yuri L. R.. Universidade Federal do Espírito Santo; Brasil Fil: Costa, Leonora Pires. Universidade Federal do Espírito Santo; Brasil Fil: Mello, Marco Aurelio Ribeiro. Universidade Federal de Minas Gerais; Brasil Fil: Fischer, Erich. Universidade Federal do Mato Grosso do Sul; Brasil Fil: Passos, Fernando C.. Universidade Federal do Paraná; Brasil Fil: Varzinczak, Luiz H.. Universidade Federal do Paraná; Brasil Fil: Prevedello, Jayme A.. Universidade do Estado de Rio do Janeiro; Brasil Fil: Cruz-Neto, Ariovaldo P.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Carvalho, Fernando. Universidade do Extremo Sul Catarinense; Brasil Fil: Reis Percequillo, Alexandre. Universidade de Sao Paulo; Brasil Fil: Paviolo, Agustin Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; Argentina Fil: Duarte, José M. B.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil. Fundación Oswaldo Cruz; Brasil Fil: Bernard, Enrico. Universidade Federal de Pernambuco; Brasil Fil: Agostini, Ilaria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; Argentina Fil: Lamattina, Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina. Ministerio de Salud de la Nación; Argentina Fil: Vanderhoeven, Ezequiel Andres. Ministerio de Salud de la Nación; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina

The physiology of the long-furred woolly mouse opossum (Micoureus paraguayanus) conformed to that of other marsupials. Body temperature at thermoneutrality (all values reported as mean ± SE) was 33.3°C ± 0.3°C and basal metabolic rate was 0.760 ± 0.074 ml O2 g−1 h−1. Opossums were thermolabile at low ambient temperature (Ta) but still maintained a considerable differential between body temperature and Ta, with an increase in metabolic heat production as Ta decreased. This was accommodated by an increase in minute volume, mediated by an increase in both respiratory frequency and tidal volume at low Ta. Basal respiratory frequency was 34.2 ± 3.8 breaths/min and tidal volume was 1.62 ± 0.28 ml; minute volume was 53 ± 7 ml/min. Oxygen extraction remained constant at 13.6% ± 1.1%. Wet thermal conductance was high (0.338 ± 0.091 ml O2 g−1 h−1 °C−1; 185% of predicted) but conformed statistically to that of other marsupials. A positive relationship existed between ambient temperature and evaporative wate...

The honey possum is the only non-volant mammal to feed exclusively on a diet of nectar and pollen. Like other mammalian and avian nectarivores, previous studies indicated that the honey possum's basal metabolic rate was higher than predicted for a marsupial of equivalent body mass. However, these early measurements have been questioned. We re-examined the basal metabolic rate (2.52 +/- 0.222 ml O(2) g(-1) h(-1)) of the honey possum and confirm that it is indeed higher (162%) than predicted for other marsupials both before and after accounting for phylogenetic history. This, together with its small body mass (5.4 +/- 0.14 g; 1.3% of that predicted by phylogeny) may be attributed to its nectarivorous diet and mesic distribution. Its high-basal metabolic rate is associated with a high-standard body temperature (36.6 +/- 0.48 degrees C) and oxygen extraction (19.4%), but interestingly the honey possum has a high point of relative water economy (17.0 degrees C) and its standard evaporative water loss (4.33 +/- 0.394 mg H(2)O g(-1) h(-1)) is not elevated above that of other marsupials, despite its mesic habitat and high dietary water intake.

We present the first complete study of basic laboratory-measured physiological variables (metabolism, thermoregulation, evaporative water loss, and ventilation) for a South American marsupial, the gracile mouse opossum (Gracilinanus agilis). Body temperature (T(b)) was thermolabile below thermoneutrality (T(b) = 33.5 degrees C), but a substantial gradient between T(b) and ambient temperature (T(a)) was sustained even at T(a) = 12 degrees C (T(b) = 30.6 degrees C). Basal metabolic rate of 1.00 mL O2 g(-1) h(-1) at T(a) = 30 degrees C conformed to the general allometric relationship for marsupials, as did wet thermal conductance (5.7 mL O2 g(-1) h(-1) degrees C(-1)). Respiratory rate, tidal volume, and minute volume at thermoneutrality matched metabolic demand such that O2 extraction was 12.4%, and ventilation increased in proportion to metabolic rate at low T(a). Ventilatory accommodation of increased metabolic rate at low T(a) was by an increase in respiratory rate rather than by tidal volume or O2 extraction. Evaporative water loss at the lower limit of thermoneutrality conformed to that of other marsupials. Relative water economy was negative at thermoneutrality but positive below T(a) = 12 degrees C. Interestingly, the Neotropical gracile mouse opossums have a more positive water economy at low T(a) than an Australian arid-zone marsupial, perhaps reflecting seasonal variation in water availability for the mouse opossum. Torpor occurred at low T(a), with spontaneous arousal when T(b)20 degrees C. Torpor resulted in absolute energy and water savings but lower relative water economy. We found no evidence that gracile mouse opossums differ physiologically from other marsupials, despite their Neotropical distribution, sympatry with placental mammals, and long period of separation from Australian marsupials.

Rodents from arid and semi-arid deserts are faced with the problem of water conservation. The physiological responses of small rodents to such conditions have been intensively investigated over broad geographically disjunct areas. Despite the presence of xeric habitats in South America since the late Tertiary, some studies suggest that sigmodontine South-American desert rodents do not display the same diversity of physiological responses at the species level as those observed in other desert-dwelling species of rodents. In this paper, we analyzed the physiological responses to water deprivation, at the interespecific and interindividual level, among eight species of sigmodontine desert-dwelling rodents from different geographical areas within South-American deserts. Using randomization tests, we found no significant phylogenetic signal for resistance to water deprivation or for individual variability in this response. Contrary to our initial predictions, we observed that sigmodontine rodents from arid/semi-arid habitats (Monte Desert) had significantly lower rates of body mass loss per day (higher tolerances to water deprivation) than species from the hyperarid deserts. We showed that sigmodontine rodents from South America showed a remarkable diversity of physiological mechanisms for coping with water shortage resulting from different evolutionary adaptive strategies. This diversity, however, displays a rather unexpected pattern in terms of its geographical distribution.

SUMMARY Broad nosed caiman are ectotherm sauropsids that naturally experience long fasting intervals. We have studied the postprandial responses by measuring oxygen consumption using respirometry, the size changes of the duodenum, the distal small intestine, and the liver, using repeated non-invasive ultrasonography, and by investigating structural changes on the level of tissues and cells by using light- and electron microscopy. The caimans showed the same rapid and reversible changes of organ size and identical histological features, down to the ultrastructure level, as previously described for other ectothermic sauropsids. We found a configuration change of the mucosa epithelium from pseudostratified during fasting to single layered during digestion, in association with hypertrophy of enterocytes by loading them with lipid droplets. Similar patterns were also found for the hepatocytes of the liver. By placing the results of our study in comparative relationship and by utilizing the phylogenetic bracket of crocodiles, birds and squamates, we suggest that the observed features are plesiomorphic characters of sauropsids. By extending the comparison to anurans, we suggest that morphological and physiological adjustments to feeding and fasting described here may have been a character of early tetrapods. In conclusion, we suggest that the ability to tolerate long fasting intervals and then swallow a single large meal as described for many sit-an-wait foraging sauropsids is a functional feature that was already present in ancestral tetrapods.

Acting in the hypothalamus, tumor necrosis factor-alpha (TNF-alpha) produces a potent anorexigenic effect. However, the molecular mechanisms involved in this phenomenon are poorly characterized. In this study, we investigate the capacity of TNF-alpha to activate signal transduction in the hypothalamus through elements of the pathways employed by the anorexigenic hormones insulin and leptin. High dose TNF-alpha promotes a reduction of 25% in 12h food intake, which is an inhibitory effect that is marginally inferior to that produced by insulin and leptin. In addition, high dose TNF-alpha increases body temperature and respiratory quotient, effects not reproduced by insulin or leptin. TNF-alpha, predominantly at the high dose, is also capable of activating canonical pro-inflammatory signal transduction in the hypothalamus, inducing JNK, p38, and NFkappaB, which results in the transcription of early responsive genes and expression of proteins of the SOCS family. Also, TNF-alpha activates signal transduction through JAK-2 and STAT-3, but does not activate signal transduction through early and intermediary elements of the insulin/leptin signaling pathways such as IRS-2, Akt, ERK and FOXO1. When co-injected with insulin or leptin, TNF-alpha, at both high and low doses, partially impairs signal transduction through IRS-2, Akt, ERK and FOXO1 but not through JAK-2 and STAT-3. This effect is accompanied by the partial inhibition of the anorexigenic effects of insulin and leptin, when the low, but not the high dose of TNF-alpha is employed. In conclusion, TNF-alpha, on a dose-dependent way, modulates insulin and leptin signaling and action in the hypothalamus.

Rapid absorption and elimination of dietary water should be particularly important to flying species and were predicted to vary with the water content of the natural diet. Additionally, high water absorption capacity was predicted to be associated with high paracellular nutrient absorption due to solvent drag. We compared the water absorption rates of sanguivorous, nectarivorous, frugivorous, and insectivorous bats in intestinal luminal perfusions. High water absorption rates were associated with high expected dietary water load but were not highly correlated with previously measured rates of (paracellular) arabinose clearance. In conjunction with these tests, we measured water absorption and the paracellular absorption of nutrients in the intestine and stomach of vampire bats using luminal perfusions to test the hypothesis that the unique elongated vampire stomach is a critical site of water absorption. Vampire bats’ gastric water absorption was high compared to mice but not compared to their intestines. We therefore conclude that (1) dietary water content has influenced the evolution of intestinal water absorption capacity in bats, (2) solvent drag is not the only driver of paracellular nutrient absorption, and (3) the vampire stomach is a capable but not critical location for water absorption. Fil: Price, Edwin R.. University of Wisconsin; Estados Unidos Fil: Brun, Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Ciencias Humanas; Argentina Fil: Gontero Fourcade, Manuel Nicolas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Ciencias Humanas; Argentina Fil: Fernández Marinone, Guido. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Ciencias Humanas; Argentina Fil: Cruz Neto, Ariovaldo P.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Karasov, William H.. University Of Wisconsin; Estados Unidos Fil: Caviedes Vidal, Enrique Juan Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Ciencias Humanas; Argentina. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Departamento de Bioquímica y Ciencias Biológicas; Argentina

Made available in DSpace on 2018-11-26T16:16:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-09-01 CONACYT UNAM-DGAPA State University of Sao Paulo (PROPG - UNESP) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Frugivorous animals may face an osmoregulatory challenge due to the watery nature of their food and low concentration of electrolytes therein. We examined the effects of salt content (NaCl) and sugar type (sucrose vs. glucose) on the intake rate of dilute sugar solutions by the Egyptian fruit bat (Rousettus aegyptiacus). Increased salt content did not bring about an increase in energy intake by bats fed dilute sucrose diets and the bats did not compensate by hyperphagia to achieve the energy intake of bats fed concentrated sucrose solution without salt. Moreover, increasing salt content had a negative effect on the total energy intake of Egyptian fruit bats fed equicaloric sucrose solutions. There were no differences in hematocrit in bats fed the diets of different sucrose concentration, but plasma osmolality was higher in those bats fed more concentrated sugar solutions, and urine osmolality was higher in those fed on high-salt diets. Food and energy intake did not differ between bats that were fed dilute glucose and sucrose solutions. Our findings indicate that Egyptian fruit bats do not modulate food intake when salt content of dilute sugar solutions is increased, and that increasing salt content might constrain their food intake rate. Sugar type did not affect food intake by Egyptian fruit bats, indicating that sucrose hydrolysis alone does not limit the intake of dilute sugar nectar. (C) 2015 Deutsche Gesellschaft fiir Saugetierkunde. Published by Elsevier GmbH. All rights reserved. Univ Nacl Autonoma Mexico, Inst Biol, Estn Biol Chamela, San Patricio 48980, Jalisco, Mexico Univ Estadual Paulista, IB, Dept Zool, BR-13506900 Sao Paulo, Brazil Nicholas Copernicus Univ, Dept Vertebrate Zool, Torun, Poland Ben Gurion Univ Negev, Jacob Blaustein Inst Desert Res, Mitrani Dept Desert Ecol, IL-84900 Midreshet Ben Gurion, Israel Univ Estadual Paulista, IB, Dept Zool, BR-13506900 Sao Paulo, Brazil CONACYT: 146770 CONACYT: 100035 UNAM-DGAPA: 1404 FAPESP: 08/57687-0

Short-term cold exposure of homeothermic animals leads to higher thermogenesis and food consumption accompanied by weight loss. An analysis of cDNA-macroarray was employed to identify candidate mRNA species that encode proteins involved in thermogenic adaptation to cold. A cDNA-macroarray analysis, confirmed by RT-PCR, immunoblot, and RIA, revealed that the hypothalamic expression of melanin-concentrating hormone (MCH) is enhanced by exposure of rats to cold environment. The blockade of hypothalamic MCH expression by antisense MCH oligonucleotide in cold-exposed rats promoted no changes in feeding behavior and body temperature. However, MCH blockade led to a significant drop in body weight, which was accompanied by decreased liver glycogen, increased relative body fat, increased absolute and relative interscapular brown adipose tissue mass, increased uncoupling protein 1 expression in brown adipose tissue, and increased consumption of lean body mass. Thus, increased hypothalamic MCH expression in rats exposed to cold may participate in the process that allows for efficient use of energy for heat production during thermogenic adaptation to cold.

We quantified the oxygen uptake rates ( V O 2 ) and time spent, during the constriction, inspection, and ingestion of prey of different relative sizes, by the prey-constricting boid snake Boa constrictor amarali. Time spent in prey constriction varied from 7.6 to 16.3 min, and V O 2 during prey constriction increased 6.8-fold above resting values. This was the most energy expensive predation phase but neither time spent nor metabolic rate during this phase were correlated with prey size. Similarly, prey size did not affect the V O 2 or duration of prey inspection. Prey ingestion time, on the other hand, increased linearly with prey size although V O 2 during this phase, which increased 4.9-fold above resting levels, was not affected by prey size. The increase in mechanical difficulty of ingesting larger prey, therefore, was associated with longer ingestion times rather than proportional increases in the level of metabolic effort. The data indicate that prey constriction and ingestion are largely sustained by glycolysis and the intervening phase of prey inspection may allow recovery between these two predatory phases with high metabolic demands. The total amount of energy spent by B. c. amarali to constrict, inspect, and ingest prey of sizes varying from 5 to 40% of snake body mass varied inversely from 0.21 to 0.11% of the energy assimilated from the prey, respectively. Thus, prey size was not limited by the energetic cost of predation. On the contrary, snakes feeding on larger prey were rewarded with larger energetic returns, in accordance with explanations of the evolution of snake feeding specializations.

Water-soluble nutrients are absorbed by the small intestine via transcellular and paracellular mechanisms. Based on a few previous studies, the capacity for paracellular nutrient absorption seems greater in flying mammals than in nonflying mammals, but there has been little investigation of the mechanisms driving this difference. Therefore, we studied three species each of bats (Artibeus lituratus, Sturnira lilium and Carollia perspicillata) and nonflying mammals (Akodon montensis, Mus musculus and Rattus norvegicus). Using standard pharmacokinetic techniques in intact animals, we confirmed the greater paracellular nutrient absorption in the fliers, comparing one species in each group. Then we conducted in situ intestinal perfusions on individuals of all species. In both approaches, we measured the absorption of 3OMD-glucose, a nonmetabolizable glucose analog absorbed both paracellularly and transcellularly, as well as l-arabinose, which has no mediated transport. Fractional absorption of l-arabinose was three times higher in the bat (S. lilium: 1.2±0.24) than in the rodent (A. montensis: 0.35±0.04), whereas fractional absorption of 3OMD-glucose was complete in both species (1.46±0.4 and 0.97±0.12, respectively). In agreement, bats exhibited two to 12 times higher l-arabinose clearance per square centimeter nominal surface area than rodents in intestinal perfusions. Using l-arabinose, we estimated that the contribution of the paracellular pathway to total glucose absorption was higher in all three bats (109–137%) than in the rodents (13–39%). These findings contribute to an emerging picture that reliance on the paracellular pathway for nutrient absorption is much greater in bats relative to nonflying mammals and that this difference is driven by differences in intestinal permeability to nutrient-sized molecules. Fil: Brun, Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina Fil: Price, Edwin R.. University Of Wisconsin; Estados Unidos Fil: Gontero Fourcade, Manuel Nicolas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina Fil: Fernández Marinone, Guido. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Departamento de Bioquímica y Ciencias Biológicas; Argentina Fil: Cruz Neto, Ariovaldo P.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Caviedes Vidal, Enrique Juan Raul. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Departamento de Bioquímica y Ciencias Biológicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina Fil: Karasov, William H.. University of Wisconsin; Estados Unidos

Studies on birds have led to the hypothesis that increased intestinal absorption between enterocytes (paracellular) evolved as a compensation for smaller intestinal size in fliers, which was perhaps selected to minimize the mass of digesta carried. This hypothesis predicts that bats will also exhibit relatively reduced intestinal size and high paracellular absorption, compared with nonflying mammals. Published studies on three bat species indicate relatively high paracellular absorption. One mechanism for increasing paracellular absorption per cm2 small intestine (SI) is increased number of tight junctions (TJs) across which paracellular absorption occurs. To our knowledge, we provide the first comparative analysis of enterocyte size and number in flying and nonflying mammals. Intestines of insectivorous bats Tadarida brasiliensis were compared with Mus musculus using hematoxylin and eosin staining method. Bats had shorter and narrower SIs than mice, and after correction for body size difference by normalizing to mass3/4, the bats had 40% less nominal surface area than the mouse, as predicted. Villous enhancement of surface area was 90% greater in the bat than in the mouse, mainly because of longer villi and a greater density of villi in bat intestines. Bat and mouse were similar in enterocyte diameter. Bats exceeded mice by 54.4% in villous area per cm length SI and by 95% in number of enterocytes per cm2 of the nominal surface area of the SI. Therefore, an increased density of TJs per cm2 SI may be a mechanistic explanation that helps to understand the high paracellular absorption observed in bats compared to nonflying mammals.