Valesca Veiga Cardoso

Micronuclei in red blood cells of armored catfish Hypostomus plecotomus exposed to potassium dichromate

The present work aims to evaluate the impact of potassium dichromate in armored catfishes’ (Hypostomus plecotomus) erythropoiesis, using piscine micronucleus test. Armored catfishes (n = 30) were subjected to 12 mg/L of potassium dichromate, with an equal control group (n = 30). For each 2,000 red blood cells of animals subjected to treatment, it was possible to observe 8.25 ± 0.02% cells with micronuclei and 17 ± 0.005 mg/kg of total chrome in tissues, detected through atomic absorption spectrophotometry. In the control group, the average was 0.75 ± 0.03% for micronuclei and 1.08 ± 0.04 mg/kg of chrome in tissues. The results confirm the clastogenic effect of potassium dichromate. The sensibility to this ion and the economic relevance of H. plecotomus show that armored catfish can be used to monitor acute effects of metallic pollutant spills in freshwater.

THE EFFECTS OF CONSTANT AND ALTERNATING TEMPERATURES ON THE REPRODUCTIVE POTENTIAL, LIFE SPAN, AND LIFE EXPECTANCY OF Anastrepha fraterculus (WIEDEMANN) (DIPTERA: TEPHRITIDAE)

Ovarian development, oviposition, larval eclosion, ornithine decarboxylase (ODC) activity, ovarian, testis and ejaculatory apodeme measurements (length, width, and area), and the number of spermatozoa of Anastrepha fraterculus (Wiedemann) were analyzed at alternating (20 degrees/6 degrees C and 20 degrees/13 degrees C) and constant (6 degrees C; 25 degrees C) temperatures. Life span and life expectancy were also analyzed for both genders. All the results suggest that temperature, especially alternating temperatures, increase not only male and female reproductive potential but also their life span and life expectancy. These changes can be a powerful strategy triggered by A. fraterculus as a means to survive the stressful temperature conditions found in winter in the apple production region in Brazil, enabling this species to increase its population density and cause apple damage when spring begins.

Hepatic and seric levels of purines in rats experimentally infected by Fasciola hepatica

The aim of this study was to evaluate hepatic and seric levels of purines, as well as their breakdown products in rats infected by Fasciola hepatica on days 15 and 87 post-infection (PI). Rats were divided into two groups: uninfected (n = 10) and infected (n = 20). On day 15 (n = 5 for uninfected group and n = 10 for infected group) and 87 PI (n = 5 for uninfected group and n = 10 for infected group), animals were euthanized for sampling to evaluate levels of purines by high-performance liquid chromatography. In serum, ATP increased (P < 0.05) and ADP decreased (P < 0.05) on days 15 and 87 PI, while AMP increased (P < 0.05) only on day 15 PI. Hypoxanthine levels increased (P < 0.05) on days 15 and 87 PI, while adenosine and xanthine levels decreased and increased (P < 0.05), respectively, on day 87 PI. No difference was observed regarding seric inosine and uric acid (P > 0.05). Hepatic ATP, adenosine, and uric acid levels decreased (P < 0.05) on days 15 and 87 PI. AMP levels decreased (P < 0.05) on day 87 PI, while xanthine levels increased (P < 0.05) on day 15 PI in the liver. Also in the liver, hypoxanthine levels increased (P < 0.05) on day 15 PI and decreased (P < 0.05) on day 87 PI. On the other hand, there was no difference on hepatic ADP and inosine levels (P > 0.05). Therefore, it is possible to conclude that F. hepatica infection can change purine levels, which may be associated with an inflammatory process, and these alterations may influence fasciolosis pathogenesis.

Changes in purine levels associated with cellular brain injury in gerbils experimentally infected with Neospora caninum.

The present study was carried out in order to assess the possible alterations in purine levels of brain, associated neuronal lesions in gerbils experimentally infected with Neospora caninum. For that, gerbils (Meriones unguiculatus) were inoculated with Nc-1 strain of N. caninum, composing two different experiments: Experiment I (EI) and experiment II (EII), where purine levels were measured along with the histopathologic study, on days 7 (EI), 15 and 30 (EII), post-infection (PI). As a result, it was possible to observe that the purine levels (ATP, ADP, AMP, adenosine, inosine and xanthine) in brain in EI are significantly reduced (p < 0.05), while in EII we faced a different pattern, since in the majority the purine levels were significantly increased (p < 0.05) on days 15 (ATP, AMP, adenosine, hypoxanthine and xanthine) and 30 PI (ATP, ADP, AMP, adenosine, and uric acid). Results of brain histopathology did not show histological lesion in animals of EI; however, in gerbils of EII it was possible to verify that the alterations (lesions) were more pronounced in gerbils evaluated on day 30 PI when compared to day 15 PI. Therefore, it was possible to conclude that the purine levels in brain were altered in both experiments, concomitant with the histopathological injuries observed in EII.

Physical training normalizes nucleotide hydrolysis and biochemical parameters in blood serum from streptozotocin-diabetic rats

Ectonucleotidases and the nucleotide metabolism have been implicated as important regulators in diabetes disease. We evaluated the ectonucleotidase activities and biochemical parameters in blood serum of streptozotocin (STZ)-induced diabetic rats submitted a physical training protocol. We observed a raise in ATP, ADP, AMP and p-Nph-5′-TMP hydrolysis rate and in the levels of cholesterol and triglycerides in rat blood serum, after 30 days of diabetes induction. However, in serum of rats submitted a physical training protocol by forced swimming, both the nucleotide hydrolysis rate and the lipids levels returned to the control values. Considering that diabetes leads to multiple pathophysiological alterations, the modulations observed in ectonucleotidase activities may be part of the events involved in these alterations. Then the physical training is a very important way to control the vascular alterations developed in diabetes.

Effect of α-difluormethylornithine on Anastrepha fraterculus (Diptera, Tephritidae) ovary size

Ovarian sizes (length and width) were measured in young females of Anastrepha fraterculus (Wiedemann) (Diptera, Tephritidae) subjected or not to the inhibitor alpha-difluormethylornithine (alpha-DFMO). The most effective concentration of alpha-DMFO used was 50 mM and the ovarian measurements (length and width) of the treated females were smaller than those of females not treated with alpha-DMFO. These data may suggest some relationship between ornithine decarboxylase (ODC) and sexual maturation in A. fraterculus.