Body mass is one of the most influencing factors of metabolic rate and gas exchange of animals, a... more Body mass is one of the most influencing factors of metabolic rate and gas exchange of animals, and also related to activity pattern and occupancyof ecological niches. This study aimed to understand the relationships between body mass (MB) and morpho-functional features ofthe lungs of Iguana iguana, through morphological and morphometric characterization of the structural elements of the respiratory system.Iguana iguana has lungs of the transitional type, the heterogeneously distributed parenchyma being faveolar in cranial and medial regionsand trabecular in the caudal region. Within the parenchyma, 43.6 ± 25.5% corresponds to faveoli, 18.0 ± 5.9% to interfaveolar septa, and38.7 ± 31.6% to trabeculae. Within the interfaveolar septa, 9.4 ± 4.0% corresponds to blood capillaries, 4.4 ± 1.0% to type I pneumocytes And 3.9 ± 1.1% to type II pneumocytes. Allometric analyses showed that lung (MB 0.8949) and parenchymal volume (MB 1.030) scale with MB in I. iguana just as in other lizards wi...
The respiratory system of snakes, composed of a trachea and one or two lungs, shows considerable ... more The respiratory system of snakes, composed of a trachea and one or two lungs, shows considerable variation in terms of size and complexity, especially in terms of length and distribution of the respiratory epithelium. The importance of heart position within snakes has previously been investigated concerning gravitational stress. The relationship between respiratory gas exchange epithelium and heart position, however, has not been addressed in detail, which seems necessary, since the heart needs to pump blood through the pulmonary circulation for effective gas exchange. Herein, we analyze the morphology of the respiratory epithelium in Boa constrictor and Crotalus durissus stereologically regarding the composition of the gas exchange tissue and the distribution of blood vessels within the vascularized parts of the respiratory system. The gas exchange epithelium is composed of blood capillaries, larger vessels, trabeculae, and septa, forming an overall faveolar-type epithelium in both...
The respiratory system of chelonians needs to function within a mostly solid carapace, with venti... more The respiratory system of chelonians needs to function within a mostly solid carapace, with ventilation depending on movements of the flanks. When submerged, inspiration has to work against hydrostatic pressure. We examined breathing mechanics in Trachemys scripta while underwater. Additionally, as the respiratory system of T. scripta possesses a well-developed post-pulmonary septum (PPS), we investigated its role by analyzing the breathing mechanics of lungs with and without their PPS attached. Static compliance was significantly increased in submerged animals and in animals with and without their PPS, while removal of the PPS did not result in a significantly different static compliance. Dynamic compliance was significantly affected by changes in volume and frequency in every treatment, with submergence significantly decreasing dynamic compliance. The presence of the PPS significantly increased dynamic compliance. Submersion did not significantly alter work per ventilation, but ca...
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2021
Ambush-foraging snakes that ingest large meals might undergo several months without eating when t... more Ambush-foraging snakes that ingest large meals might undergo several months without eating when they use the internal reserves to support the energetic costs of living. Then, morphological and physiological processes might be orchestrated during the transition from fasting to the postprandial period to rapidly use the energetic stores while the metabolic rate is elevated in response to food intake. To understand the patterns of substrates deposition after feeding, we accessed the morphological and biochemical response in Boa constrictor snakes after two months of fasting and six days after feeding. We followed the plasma levels of glucose, total proteins, and total lipids, and we performed the stereological ultrastructural analysis of the liver and the proximal region of the intestine to quantify glycogen granules and lipid droplets. In the same tissues and stomach, we measured the activity of the enzyme fructose-1,6-biphosphatase (FBPase1) involved in the gluconeogenic pathway, and we measured pyruvate kinase (PK) and lactate dehydrogenase (LDH) enzymatic activities involved in the anaerobic pathway in the liver. Briefly, our results indicated an increase in boas' plasma glucose one day after meal intake compared to unfed snakes. The hepatic glycogen reserves were continuously restored within days after feeding. Also, the enzymes involved in the energetic pathways increased activity six days after feeding in the liver. These findings suggest a quick restoring pattern of energetic stores during the postprandial period.
The embryonic development of parabronchi occurs mainly during the second half of incubation in pr... more The embryonic development of parabronchi occurs mainly during the second half of incubation in precocious birds, which makes this phase sensitive to possible morphological modifications induced by O2 supply limitation. Thus, we hypothesized that hypoxia during the embryonic phase of parabronchial development induces morphological changes that remain after hatching. To test this hypothesis, chicken embryos were incubated entirely (21 days) under normoxia or partially under hypoxia (15% O2 during days 12 to 18). Lung structures, including air capillaries, blood capillaries, infundibula, atria, parabronchial lumen, bronchi, blood vessels larger than capillaries (Bv) and interparabronchial tissue (It), in 1- and 10-day-old chicks were analyzed using light microscopy-assisted stereology. Tissue barrier and surface area of air capillaries were measured using electron microscopy-assisted stereology, allowing for calculation of the anatomical diffusion factor. Hypoxia increased the relative...
The structure and function of crocodilian lungs are unique compared to other reptiles. We examine... more The structure and function of crocodilian lungs are unique compared to other reptiles. We examine the extent to which this, and the semi-aquatic lifestyle of crocodilians affect their respiratory mechanics. We measured changes in intratracheal pressure in adult and juvenile caiman (Caiman yacare) during static and dynamic lung volume changes. Respiratory mechanics of juvenile caiman were additionally measured while floating in water and submerged at 30°, 60°, and 90° to the water's surface. The static compliance of the juvenile pulmonary system (2.89±0.22 mL cmH2O 100g−1) was greater than that of adults (1.2±0.41 ml cmH2O 100g−1), suggesting that the system stiffens as the body wall becomes more muscular and keratinized in adults. For both age groups, the lungs were much more compliant than the body wall, offering little resistance to air flow (15.35 and 4.25 for lungs, versus 3.39 and 1.67 mL cmH2O 100g−1 for body wall, in juveniles and adults respectively). Whole system dynami...
1 Launching Current Ethology is the latest step to improve visibility of ethology in Brazil and a... more 1 Launching Current Ethology is the latest step to improve visibility of ethology in Brazil and abroad. From a humble start at the Instituto de Psicologia (IP), University of São Paulo, at the laboratory of Prof. Walter Hugo de Andrade Cunha, ethology in Brazil shows its strength through its graduation programs and institutionalized features, such as regular meetings, a sound society and a journal, Revista de Etologia, converted into Current Ethology from now on (Fuchs, 1995; Ades, 2010; Otta et al., 2013; Spinelli de Oliveira et al., 2014; Spinelli de Oliveira and Magrini, 2015; Magrini and Spinelli de Oliveira, 2015). Prof. Cesar Ades, another name from the IP, was one of the key figures whose work stimulated interest in ethology among Brazilians from the seventies until his premature death in 2012. He was responsible for bringing G. Baerendsas as guest of the I Congresso Latinoamericano de Psicologia in 1973, in São Paulo, the same year in which the Noble Prize in Medicine or Phy...
Body mass is one of the most influencing factors of metabolic rate and gas exchange of animals, a... more Body mass is one of the most influencing factors of metabolic rate and gas exchange of animals, and also related to activity pattern and occupancyof ecological niches. This study aimed to understand the relationships between body mass (MB) and morpho-functional features ofthe lungs of Iguana iguana, through morphological and morphometric characterization of the structural elements of the respiratory system.Iguana iguana has lungs of the transitional type, the heterogeneously distributed parenchyma being faveolar in cranial and medial regionsand trabecular in the caudal region. Within the parenchyma, 43.6 ± 25.5% corresponds to faveoli, 18.0 ± 5.9% to interfaveolar septa, and38.7 ± 31.6% to trabeculae. Within the interfaveolar septa, 9.4 ± 4.0% corresponds to blood capillaries, 4.4 ± 1.0% to type I pneumocytes And 3.9 ± 1.1% to type II pneumocytes. Allometric analyses showed that lung (MB 0.8949) and parenchymal volume (MB 1.030) scale with MB in I. iguana just as in other lizards wi...
The respiratory system of snakes, composed of a trachea and one or two lungs, shows considerable ... more The respiratory system of snakes, composed of a trachea and one or two lungs, shows considerable variation in terms of size and complexity, especially in terms of length and distribution of the respiratory epithelium. The importance of heart position within snakes has previously been investigated concerning gravitational stress. The relationship between respiratory gas exchange epithelium and heart position, however, has not been addressed in detail, which seems necessary, since the heart needs to pump blood through the pulmonary circulation for effective gas exchange. Herein, we analyze the morphology of the respiratory epithelium in Boa constrictor and Crotalus durissus stereologically regarding the composition of the gas exchange tissue and the distribution of blood vessels within the vascularized parts of the respiratory system. The gas exchange epithelium is composed of blood capillaries, larger vessels, trabeculae, and septa, forming an overall faveolar-type epithelium in both...
The respiratory system of chelonians needs to function within a mostly solid carapace, with venti... more The respiratory system of chelonians needs to function within a mostly solid carapace, with ventilation depending on movements of the flanks. When submerged, inspiration has to work against hydrostatic pressure. We examined breathing mechanics in Trachemys scripta while underwater. Additionally, as the respiratory system of T. scripta possesses a well-developed post-pulmonary septum (PPS), we investigated its role by analyzing the breathing mechanics of lungs with and without their PPS attached. Static compliance was significantly increased in submerged animals and in animals with and without their PPS, while removal of the PPS did not result in a significantly different static compliance. Dynamic compliance was significantly affected by changes in volume and frequency in every treatment, with submergence significantly decreasing dynamic compliance. The presence of the PPS significantly increased dynamic compliance. Submersion did not significantly alter work per ventilation, but ca...
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2021
Ambush-foraging snakes that ingest large meals might undergo several months without eating when t... more Ambush-foraging snakes that ingest large meals might undergo several months without eating when they use the internal reserves to support the energetic costs of living. Then, morphological and physiological processes might be orchestrated during the transition from fasting to the postprandial period to rapidly use the energetic stores while the metabolic rate is elevated in response to food intake. To understand the patterns of substrates deposition after feeding, we accessed the morphological and biochemical response in Boa constrictor snakes after two months of fasting and six days after feeding. We followed the plasma levels of glucose, total proteins, and total lipids, and we performed the stereological ultrastructural analysis of the liver and the proximal region of the intestine to quantify glycogen granules and lipid droplets. In the same tissues and stomach, we measured the activity of the enzyme fructose-1,6-biphosphatase (FBPase1) involved in the gluconeogenic pathway, and we measured pyruvate kinase (PK) and lactate dehydrogenase (LDH) enzymatic activities involved in the anaerobic pathway in the liver. Briefly, our results indicated an increase in boas' plasma glucose one day after meal intake compared to unfed snakes. The hepatic glycogen reserves were continuously restored within days after feeding. Also, the enzymes involved in the energetic pathways increased activity six days after feeding in the liver. These findings suggest a quick restoring pattern of energetic stores during the postprandial period.
The embryonic development of parabronchi occurs mainly during the second half of incubation in pr... more The embryonic development of parabronchi occurs mainly during the second half of incubation in precocious birds, which makes this phase sensitive to possible morphological modifications induced by O2 supply limitation. Thus, we hypothesized that hypoxia during the embryonic phase of parabronchial development induces morphological changes that remain after hatching. To test this hypothesis, chicken embryos were incubated entirely (21 days) under normoxia or partially under hypoxia (15% O2 during days 12 to 18). Lung structures, including air capillaries, blood capillaries, infundibula, atria, parabronchial lumen, bronchi, blood vessels larger than capillaries (Bv) and interparabronchial tissue (It), in 1- and 10-day-old chicks were analyzed using light microscopy-assisted stereology. Tissue barrier and surface area of air capillaries were measured using electron microscopy-assisted stereology, allowing for calculation of the anatomical diffusion factor. Hypoxia increased the relative...
The structure and function of crocodilian lungs are unique compared to other reptiles. We examine... more The structure and function of crocodilian lungs are unique compared to other reptiles. We examine the extent to which this, and the semi-aquatic lifestyle of crocodilians affect their respiratory mechanics. We measured changes in intratracheal pressure in adult and juvenile caiman (Caiman yacare) during static and dynamic lung volume changes. Respiratory mechanics of juvenile caiman were additionally measured while floating in water and submerged at 30°, 60°, and 90° to the water's surface. The static compliance of the juvenile pulmonary system (2.89±0.22 mL cmH2O 100g−1) was greater than that of adults (1.2±0.41 ml cmH2O 100g−1), suggesting that the system stiffens as the body wall becomes more muscular and keratinized in adults. For both age groups, the lungs were much more compliant than the body wall, offering little resistance to air flow (15.35 and 4.25 for lungs, versus 3.39 and 1.67 mL cmH2O 100g−1 for body wall, in juveniles and adults respectively). Whole system dynami...
1 Launching Current Ethology is the latest step to improve visibility of ethology in Brazil and a... more 1 Launching Current Ethology is the latest step to improve visibility of ethology in Brazil and abroad. From a humble start at the Instituto de Psicologia (IP), University of São Paulo, at the laboratory of Prof. Walter Hugo de Andrade Cunha, ethology in Brazil shows its strength through its graduation programs and institutionalized features, such as regular meetings, a sound society and a journal, Revista de Etologia, converted into Current Ethology from now on (Fuchs, 1995; Ades, 2010; Otta et al., 2013; Spinelli de Oliveira et al., 2014; Spinelli de Oliveira and Magrini, 2015; Magrini and Spinelli de Oliveira, 2015). Prof. Cesar Ades, another name from the IP, was one of the key figures whose work stimulated interest in ethology among Brazilians from the seventies until his premature death in 2012. He was responsible for bringing G. Baerendsas as guest of the I Congresso Latinoamericano de Psicologia in 1973, in São Paulo, the same year in which the Noble Prize in Medicine or Phy...
Amphibians experiencing evapotranspirative water loss may suffer dehydration. Another difficulty ... more Amphibians experiencing evapotranspirative water loss may suffer dehydration. Another difficulty is their limited tolerance to brackish water. This study aimed to investigate the effect of water salinity on behavior (activity and water conservation posture) in Leptodactylus macrosternum, in normally hydrated animals with urine in their bladder, in normally hydrated animals without urine in their bladder and in dehydrated ones with urine removed from their bladder. Experiments were filmed, behaviors were registered, and a Behavioral Dehydration Protection Index (BDPI) was calculated, using a weighted average of the postures. A GLM and Kruskall Wallis test was performed with Dunn’s multiple comparisons test to evaluate the effects of osmotic gradient stress on BDPI. It was found that emptied bladder and aerial dehydration did not influence BDPI (p = 0.832 and p = 0.142, respectively), contrary to what is seen in the literature. The different osmotic media had a significant effect on BDPI (p = 0.0003).
A central issue for ecologists is to understand the variables that determine species distribution... more A central issue for ecologists is to understand the variables that determine species distribution. Many studies have suggested that environmental variables are the main factors that shape anuran communities. Nevertheless, several natural environments have not been assessed with ecological studies of this nature, including specific ecosystems of the South American Cerrado morphoclimatic domain. In the present study, we investigated the relationship between environmental variables and the spatial distribution of anurans in ecosystems of semi-deciduous and riparian forests in a transitional region between the Cerrado and Caatinga environments in the western Bahia state, Brazil. We collected fauna and environmental variables data in 10 sampling units during two rainy periods. The original information on species composition and abundance in the community was reduced to a single axis using a non-metric multidimensional scaling method (NMDS) and environmental data were reduced to two main factors using a principal component analysis (PCA). We tested the absence of an association between the structural variation of the environment and spatial distribution of the anuran community using a multiple regression analysis. The anuran community was ordered following a gradient of dry semi-deciduous seasonal areas toward riparian forest with areas of direct insolation and lentic water bodies. Among the components extracted by the PCA, only PC1 was associated with anuran community composition, explaining 69% of the ordination obtained by the NMDS according to variables related to the presence of water bodies. The great contribution of water bodies appears to reflect the degree of modification of the landscape in the region and seasonal restrictions in the availability of water, with both aspects increasing the expected influence of water bodies on the distribution of anurans in the western Bahia state. Future investigations exploring the structure of anurofauna during dry seasons could extend and complement the results provided by this study.
Uploads
present study, we investigated the relationship between environmental variables and the spatial distribution of anurans in ecosystems of semi-deciduous and riparian forests in a transitional region between the Cerrado and Caatinga environments in the western Bahia state, Brazil.
We collected fauna and environmental variables data in 10 sampling units during two rainy periods. The original information on species composition and abundance in the community was reduced to a single axis using a non-metric multidimensional scaling method (NMDS) and environmental data were reduced to two main factors using a principal component analysis (PCA). We tested the absence of an association between the structural variation of the environment and spatial distribution of the anuran community using a multiple regression analysis. The anuran community was ordered following a gradient of dry semi-deciduous seasonal areas toward riparian forest with areas of direct insolation and lentic water bodies. Among the components extracted by the PCA, only PC1 was associated with anuran community composition, explaining 69% of the ordination obtained by the NMDS according to variables related to the presence of water bodies. The great contribution of water bodies appears to reflect the degree of modification of the landscape in the region and seasonal restrictions in the availability of water, with both aspects increasing the expected influence of water bodies on the distribution of anurans in the western Bahia state. Future investigations exploring the structure of anurofauna during dry seasons could extend and complement the results provided by this study.