Effects of acute heat exposure on respiratory metabolism and blood glucose in freshwater fishes, Prochilodus scrofa (curimbatá) and Cyprinus carpio (carp) acclimatized to tropical winter

1. 1. Routine oxygen consumption and blood glucose were determined from freshwater fishes, Prochilodus scrofa and Cyprinus carpio, exposed at high temperatures for 1 hr. 2. 2. Prochilodus scrofa had a significantly higher rate of oxygen consumption at 30°C than at 25°C, and carp higher at 25°C than at 30°C. 3. 3. Blood glucose was significantly higher for Cyprinus carpio than for Prochilodus scrofa at 25 and 30°C; however, after exposure to these temperatures for 1 hr blood glucose did not change significantly for both species. 4. 4. The results suggest that these interspecific variations may be linked to the differences between native and foreign fishes and their way of life. © 1985.

Oxygen uptake of active and aestivating earthworm Glosso scolex pa ulistus (Oligochaeta, Glossoscolecidae)

1. 1. The onset of or reactivation from aestivation in the earthworm Glossoscolex paulistus were dependent upon soil moisture. No evidence of temperature effect in the process was found either in field or laboratory data. 2. 2. Oxygen uptake measured in active and aestivating groups revealed remarkable reduction for aestivating earthworms at various temperatures studied. 3. 3. No evidences of temperature compensation in oxygen uptake was found in both groups of earthworms, indicating that reduction in oxygen uptake is the only adaptation for the aestivating G. paulistus. © 1985.

Effects of acute cold exposure on rectal temperature, blood glucose and plasma free fatty acids in alloxan-diabetic rats

These experiments were carried out to study the effects of acute cold exposure (0-2°C/4 hr) on rectal temperature, blood glucose and plasma free fatty acids (FFA) in alloxan-diabetic rats. Male Wistar rats weighing 170-190 g were used and diabetes was induced by i.v. alloxan injection (40 mg/kg body wt). Cold exposure produced severe hypothermia in diabetic rats. After 4 hr of cold, blood glucose of diabetic rats was reduced from 296±16 to 86t±12 mg/dl (P<0.01), and FFA increased slightly, but was not statistically different (P>0.05) from the initial value. As expected, interscapular brown adipose tissue (IBAT) and retroperitoneal and epididymal white adipose tissues were significantly lower in diabetic than in control rats. Cold exposure reduced total IBAT lipids in control but not in diabetic animals. The results of this experiment suggest that diabetic rats were unable to maintain body temperature in the cold, probably because of a failure to generate an adequate amount of heat by nonshivering thermogenesis in brown adipose tissue.

The respiratory responses of an amphibious snail Pomacea lineata (spix, 1827), to temperature and oxygen tension variations

1. 1. The respiratory responses of Pomacea lineata to short-term (or acute) exposure to temperature and oxygen tension variations were investigated in animals acclimated to 25°C. 2. 2. The respiratory rates increased with rising temperatures; this increase was sharper between 15 and 25°C than at any other temperature interval; a tendency to a plateau in the RT curve was recorded between 25 and 35°C. 3. 3. All animals survived well to 1 hr exposure to the extreme temperatures used (5 and 40°C). 4. 4. In two different experimental approaches, the animals showed ability to regulate the respiratory rate in declining oxygen tensions, at least down to 10% (70.8 mmHg) oxygen. 5. 5. After 1 hr exposure to hypoxic conditions, P. lineata exhibited the pattern of underpayment of the oxygen debt acquired. 6. 6. Six out of ten animals survived after 40 days in anoxia (100% nitrogen). © 1987.

Comparing the tadpoles of Hyla geographica and Hyla semilineata

External morphology, internal oral anatomy, and chondrocranial anatomy were examined for tadpoles of Hyla geographica from the Amazon rainforest, Brazil, and Hyla semilineata from the Atlantic rainforest, Brazil. Here, we provide morphological larval data to help diagnose these closely related species. Scanning electron microscopy analysis of buccal morphology showed the most distinctive features between these species: the distance between the lingual papillae in the buccal floor of H. geographica is three times greater than that distance in H. semilineata, and the relative size of the lingual papillae in H. geographica is less than half their size in H. semilineata. Although the chondrocranium of both species is identical, and the external morphology of the larvae of both taxa is very similar, they differ greatly in size at most developmental stages. A multivariate analysis of covariance, corrected for stage and size, also showed a significant difference between morphometric measurements of the two species. These differences support the existence of two separate taxa.

Energetic and physiological correlates of prey handling and ingestion in lizards and snakes

In this review, we summarize the energetic and physiological correlates of prey handling and ingestion in lizards and snakes. There were marked differences in the magnitude of aerobic metabolism during prey handling and ingestion between these two groups, although they show a similar pattern of variation as a function of relative prey mass. For lizards, the magnitude of aerobic metabolism during prey handling and ingestion also varied as a function of morphological specializations for a particular habitat, prey type, and behavior. For snakes, interspecific differences in aerobic metabolism during prey handling seem to be correlated with adaptations for prey capture (venom injection vs. constriction). During ingestion by snakes, differences in aerobic metabolism might be due to differences in cranial morphology, although allometric effects might be a potentially confounded effect. Anaerobic metabolism is used for prey handling and ingestion, but its relative contribution to total ATP production seems to be more pronounced in snakes than in lizards. The energetic costs of prey handling and ingestion are trivial for both groups and cannot be used to predict patterns of prey-size selection. For lizards, it seems that morphological and ecological factors set the constraints on prey handling and ingestion. For snakes, besides these two factors, the capacity of the cardio-respiratory system may also be an important factor constraining the capacity for prey handling and ingestion. © 2001 Elsevier B.V.

Protein requirements in larvae and adults of Scaptotrigona postica (Hymenoptera: Apidia, Meliponinae): Midgut proteolytic activity and pollen digestion

The number and degree of digestion of pollen grains in the midgut and rectum, the midgut proteolytic activity and the time of pollen grain passage through the digestive tract in the stingless bee Scaptotrigona postica (Latreille) have been analyzed. The results show similar protein requirements among larvae, nurse bees and queens, as well as between forager bees and old males, but these requirements are higher in individuals from the former groups than in those from the latter. Although protein requirements have been demonstrated to vary according to a bee's activity in the colony, they are similar among bees from different castes or sexes. These changes in feeding behavior are related to the bee's function and to less competition for nourishment among individuals of the colony. It is also noted that pollen grains took between 6 and 28 h to pass through the digestive tract. Pollen grains are irregularly accumulated in the various regions of the midgut, which may reflect functional differentiation throughout the midgut. © 2001 Elsevier B.V.

Synaptonemal complex analysis in the fish species Piaractus mesopotamicus and Colossoma macropomum, and in their interspecific hybrid

The surface-spreading technique for visualization of whole cell synaptonemal complex (SC) complements was employed to study the chromosome synapsis in spermatocytes of P. mesopotamicus, C. macropomum and in their interspecific hybrid (tambacu) with the main objective to analyze possible errors in chromosome pairing that could result in hybrid sterility. SC analysis showed that the parental species P. mesopotamicus and C. macropomum have 27 bivalents homogeneously synapsed. The SC in spermatocytes from the hybrid tambacu showed gross meiotic configurations in all cells analyzed. The spermatocytes exhibited a few chromosomes or well synapsed chromosome segments, while many chromosome segments did not have any synapsis. This result, allied to other genetical and cytogenetical evidence, reinforces the hypothesis that the hybrid tambacu is sterile. Further studies involving other aspects, such as behavior and physiology, should be conduced before the introduction of these hybrids in rivers and lakes.

Cloning and characterization of the cDNA for the Brazilian Cratomorphus distinctus larval firefly luciferase: Similarities with European Lampyris noctiluca and Asiatic Pyrocoelia luciferases

Studies on firefly (Lampyridae) luciferases have focused on nearctic species of Photinus and Photuris and Euroasiatic species of Lampyris, Luciola, Hotaria, and Pyrocoelia. Despite accounting for the greatest diversity of fireflies in the world, no molecular studies have been carried out on the highly diverse genera from the neotropical region. Here we report the luciferase cDNA cloning for the larva of the Brazilian firefly Cratomorphus distinctus. The cDNA has 1978 bp and codes for a 547-residue-long polypeptide. Noteworthy, sequence comparison as well as functional properties show the highest degree of similarity with Lampyris noctiluca (93%) and Pyrocoelia spp. (91%) luciferases, suggesting a close phylogenetic relationship despite the geographical distance separating these species. The bioluminescence emission spectrum peaks at 550 nm and, as expected, is sensitive to pH, shifting to 605 nm at pH 6. The kinetic properties of the recombinant luciferase were similar to those of other firefly luciferases. © 2004 Elsevier Inc. All rights reserved.

Reinterpretation of Malvinoconularia cahuanotensis (Braniša and Vaněk) from the Devonian Altiplano and Western Andean Cordillera, Bolivia, South America

The holotype of Malvinoconularia cahuanotensis (Braniša and Vaněk) (Devonian, Bolivia), the type species of the monospecific genus Malvinoconularia Babcock et al., is redescribed and refigured. M. cahuanotensis exhibits several gross morphological features that together are uniquely shared with Reticulaconularia baini (Babcock and Feldmann). In both taxa, the transverse ribs are nodose, the inter-spaces bear longitudinal ridges (bars or crests) that are collinear (line up) across the transverse ribs, and the longitudinal centerline (midline) of the faces is marked by a subdued ridge. Additionally, the two species may also be similar in the anatomy and external ornament of the corner sulcus. The slightly undulose geometry of the transverse ribs of M. cahuanotensis also is exhibited by certain specimens of Reticulaconularia; however, whether this feature is primary or taphonomic in origin is unclear at present. Together, these similarities suggest that the genus Malvinoconularia probably is a junior synonym of the genus Reticulaconularia. © Asociación Paleontológica Argentina.

The influence of dietary vitamin C and E supplementation on the physiological response of pirarucu, Arapaima gigas, in net culture

This study evaluated the efficacy of dietary vitamin C (ascorbic acid or AA), vitamin E (α-tocopherol or α-T), and C + E supplementation on the blood parameters of Arapaima gigas grown in net cages for 45 days. Four treatments were tested: control (commercial feed); C800; E500 and C + E (800 + 500) with supplementation of 800 mg AA kg- 1, 500 mg α-T kg- 1 and 800 + 500 mg AA + α-T kg- 1, respectively. Hematocrit (Ht), red blood cells (RBC), and hemoglobin concentration (Hb) (oxidative status indicators), thrombocytes and leukocytes (immunological indicators), plasma protein and glucose were evaluated. Fish fed vitamin C and C + E supplemented diets showed greater weight gain and survival. Dietary vitamin C and C + E diet supplementation resulted in increased Ht, Hb, RBC, MCHC, total leukocytes, total proteins, thrombocytes and eosinophils compared to the control and α-T. The α-tocopherol-supplemented diet reduced the number of total thrombocytes, lymphocytes and neutrophils and increased glucose and eosinophils relatively to the control. In general, leukocytes and thrombocytes were good indicators of the efficiency of vitamin on the defense mechanism of the A. gigas reared in cages. Results indicate that high α-T diet supplementation provides no benefit for the maintenance of the oxidative or the immunological status of A. gigas. However, it was demonstrated that high dietary AA improves A. gigas immunological status. Red blood cell indices and immune system indicators showed no synergistic effect between the vitamins after supplementing the A. gigas diet with α-T + AA. © 2006 Elsevier Inc. All rights reserved.

Usefulness of Clinical, Ultrasonographic, Hysteroscopic, and Immunohistochemical Parameters in Differentiating Endometrial Polyps From Endometrial Cancer

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Copper oxychloride fungicide and its effect on growth and oxidative stress of potato plants

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Rearing temperature induces changes in muscle growth and gene expression in juvenile pacu (Piaractus mesopotamicus)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Male Gonadal Differentiation and the Paedomorphic Evolution of the Testis in Teleostei

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)