Recrudescence of Toxoplasma gondii infection in chronically infected rats (Rattus norvegicus)

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

Isolation and multilocus genotyping of Toxoplasma gondii in seronegative rodents in Brazil

Synanthropic rodents, mainly rats and mice, become ecologically associated with men due to changes in their ecosystems caused by human activities. These animals may take part in the epidemiological cycles of several diseases, including toxoplasmosis. The presence of serum antibodies to Toxoplasma gondii in 43 rodents captured in the urban area of Umuarama, PR, Brazil, was verified by modified agglutination test (MAT). Brain and heart samples were also collected and bioassayed in mice for the isolation of the parasite. Isolated samples were analyzed by 12 multilocus genotyping. Although all rodents were seronegative, the parasite was isolated in one mouse (Mus musculus) and one rat (Rattus rattus). Genotyping showed that these samples were similar to those previously isolated from cats in the state of Parana, Brazil. (C) 2010 Elsevier B.V. All rights reserved.

Prevalence of Toxoplasma gondii antibodies in ostriches (Struthio camelus) from commercial breeding facilities in the state of São Paulo, Brazil.

Toxoplasmosis is widespread zoonosis caused by Toxoplasma gondii,a protozoan that may infect mammals and birds. The aim of the present study was to assess the prevalence of T. gondii in ostriches (Struthio camelus) from commercial breeding facilities in the state of São Paulo, Brazil, in a way to increase the knowledge on the behavior and importance of the parasite in this animal species. A total of 195 serum samples were collected from ostriches from Sorocaba, Campinas, São Carlos, Aracatuba, São Paulo, Vale do Ribeira, Botucatu and sao Jose do Rio Preto, in the state of São Paulo. These samples were analyzed by means of the Modified Agglutination Test (MAT) in order to investigate the occurrence of Toxoplasmagondii antibodies. The test showed that 14.36% of the animals were seropositive to Toxoplasmagondii. Minimum titer was considered to be equal or greater than 1:16, and the greatest dilution observed was 1:16,384. No statistically significant differences were found between males and females. Seronegative animals occurred in only two regions (São Paulo and Sao Jose do Rio Preto). These results point out the importance of further studies on this infection in ostriches, and on management practices that may minimize the risk of toxoplasmosis transmission in these birds which would, in their turn, decrease the risk for the final consumer.

Effect of organic mineral supplementation on the egg quality of semi-heavy layers in their second cycle of lay

This study was carried out to evaluate the effects of dietary trace mineral levels and sources on egg quality parameters of second-cycle semi-heavy layers. A number of 360 72-week-old layers were submitted to forced molting. Upon return of lay (83 weeks of age), birds were distributed according to a completely randomized experimental design of six treatments with six replicates of 10 birds each. The control treatment consisted of 0.10% dietary supplementation of trace minerals from inorganic sources, which was proportionally replaced by five levels (110, 100, 90, 80, 70%) of an organic trace mineral supplement containing 30, 30, 40, 6, 0.61, and 0.3 g/kg product of Zn, Fe, Mn, Cu, I, and Se, respectively. All diets contained equal protein, energy, and amino acid levels. Every 28 days of the experimental period (112 days) four eggs per replicate were collected for egg quality evaluation. The following parameters were evaluated: specific gravity, yolk, albumen and eggshell percentages, yolk index, Haugh units, and eggshell thickness and breaking strength. One sample per replicate, consisting of the pool of the yolks of three eggs collected at the end of each experimental period, was used to assess protein and mineral (Ca, P, Cu, Fe, Mn, and Zn) contents. The results were submitted to ANOVA, and means to the test of Tukey at 5% significance level. The evaluated trace mineral levels and sources did not influence any of the studied egg quality parameters. It was concluded that reducing organic trace mineral supplementation in up to 70% relative to 100% inorganic trace mineral supplementation does not affect egg parameters and therefore, can be applied to the diet of semi-heavy layers in their second cycle of lay.

Effect of the calcium level and limestone particle size on the performance of semi-heavy layers in the second cycle of egg production

An experiment was carried out at the Research and Development Unit of Brotas aiming at evaluating dietary calcium level and limestone particle size on the production performance of commercial (Hy-Line Brown) layers in the second lay cycle. Experiment duration was 112 days. A total number of 288 hens, with 83 weeks of age in the beginning of the experiment, were used in a completely randomized experimental design in a factorial arrangement of 2x3, with two calcium levels (3.5 and 4.0%) and three limestone particle size compositions: 100% fine limestone (FL), 30% coarse limestone (CL) + 70% fine limestone (FL), and 50% (CL) + 50% (FL), with six replicates of eight birds each. Egg weight (g), egg production (%), egg mass (%), feed intake (g), feed conversion ratio (kg/dz and kg/kg), mortality (%), and egg loss (%) were evaluated. The analysis of variance did not detect significant differences (p>0.05) among treatments on any of the evaluated performance parameters. It was concluded that the tested calcium levels and limestone particle composition did not influence the performance of semi-heavy layers in second production cycle.

Experimental infection of pregnant queens with two major Brazilian clonal lineages of Toxoplasma gondii

Toxoplasma gondii isolates from Brazil are biologically and genetically different from European and North America isolates. Recently, four genotypes were considered the common clonal lineages in Brazil and were designated as types BrI, BrII, BrIII, and BrIV. The pathogenicity of two major Brazilian lineages was investigated after oral inoculation of queens in the middle third of their pregnancies with T. gondii cysts. Twelve pregnant queens without T. gondii antibodies were distributed in group A (infected with a type BrI isolate); group 2 (infected with type BrIII isolate), and group 3 (non-infected control). Infection with type BrI isolate caused toxoplasmosis manifestations and abortion from one litter. Toxoplasmosis manifestations besides premature stillbirth of one litter were observed in queens infected with type BrIII isolate. Indirect fluorescence antibody test showed T. gondii antibodies in all eight infected queens at 30 days after inoculation. In two 10-day-old kittens of the same litter (group 1), titers of 16 and 64 were detected. At the same time, titers of 16, 32, and 32 were detected in three kittens from the same litter (group 2). Experimental infection with tissue cysts from a type BrI and type BrIII isolates of T. gondii developed similar reproductive disturbance in primary infected pregnant queens.

Apoptosis during the seasonal spermatogenic cycle of Rana catesbeiana

In the bullfrog Rana catesbeiana, testicular weight is constant throughout the year, but the volume densities of germinative and interstitial compartments undergo inverse changes from winter (non-breeding) to summer (breeding). The occurrence of apoptosis in the seminiferous lobules of bullfrogs was investigated in these two periods using sections stained with haematoxylin and eosin (H&E), the TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling) method and transmission electron microscopy. TUNEL-positive cells were observed in the seminiferous lobules, and ultrastructural morphological details confirmed the occurrence of cell death by apoptosis. In summer, the occurrence of several spermatogenic processes (in addition to spermiogenesis and spermiation), and then the overconsumption of Sertoli cell-derived pro-survival factors, could be responsible for the increased density of apoptotic cells. Alternatively, the low apoptotic frequency in winter could be related to the constant homeostasis in the germinative compartment given that most lobules are filled with primary spermatocytes. As volume densities of interstitial and germinative compartments undergo inverse seasonal variations through the year, the incidence of apoptosis (in summer) could play a part in controlling the spermatogenic process, maintaining the lobular size when interstitial tissue is maximally developed. In winter, the low apoptotic cell density leads to spermatogenic recrudescence and, thereby, the production of an adequate quantity of spermatozoa for the next breeding period. Thus, apoptosis may participate not only in the maintenance of spermatogenic homeostasis, but also in the cyclical control of the different spermatogenic processes according to seasonal changes of the testicular compartments as a whole.

The reproductive cycle of Callinectes danae Smith, 1869 (Decapoda, Portunidae) in the Ubatuba Region, Brazil

Callinectes danae Smith, 1869, known as siri-azul, is an important fishery resource along the Brazilian coast. The reproductive cycle of this species was studied based on their moult cycle and the development of their gonads. The animals were collected with an otter-trawl in the Ubatuba region (23 degrees 26'S 45 degrees 02'W) every other month from July 1991 to May 1993. A total of 1826 specimens were captured: 788 males and 1038 females. Ovigerous females and specimens with developed gonads in both sexes were found in all months sampled. In females, moult activity was recorded in all size classes while in males, it was verified from 20-27 mm to 90-97 mm size classes. The females produced more than one clutch during a single reproductive season, a fact evidenced by the presence of ovigerous females with ovaries in all the development phases. The species C. danae reproduces continuously, like most brachyurans from tropical waters.

Changes in the morphology and ultrastructure of the Dufour's gland during the life cycle of the bumble bee queen, Bombus terrestris L-(Hymenoptera : Bombini)

The Dufour's gland is found closely associated with the sting apparatus of all female hymenopterans, playing multiple roles among bees. In some species of Bombus the gland may be involved in production of nestmate recognition pheromones, but in B. terrestris its function is not certain yet. The morphology of the :Dufour's gland of B. terrestris queens and the ultrastructural features of its cells were studied in different ages and behavioural stages using routine transmission electron microscopy. Measurements of the length and the diameter of the gland in the same conditions were also made. The Dufour's gland of the queen increases significantly in size (both in length and in diameter) with age and reproductive activity the ultrastructural features of the gland show electrondense material that comes from the haemolymph. This material is also present in the intercellular spaces, and is conducted to the subcuticular space, to be released directly into the glandular lumen. Hence at least part of the secretion is probably taken up directly from the haemolymph. The ultrastructural features indicate a more active phase of the gland corresponding to the period of egg-laying of the queen, and a decrease in activity when the queen is in hibernation as well as after the competition point. In conclusion, the gland is probably involved in reproduction, more specifically, in the marking off eggs.

Secretory cycle of the Dufour's gland in workers of the bumble bee Bombus terrestris L-(Hymenoptera : Apidae, Bombini)

The Dufour's gland of Bombus terrestris workers, of different ages and with varying degrees of ovary development, was studied with the aim to verify its involvement in reproduction. Measurements of the diameter and the length of the gland were made using an ocular micrometer adapted to a microscope. Transmission electron microscopy was used to study the morphology of the secretory cells and to analyze the secretory cycle. The glandular cells were considered to be near type II cells of NOIROT and QUENNEDEY (1974), a type that has not been described before in Hymenopterans. The results show that there is a correlation between the degree of ovary development and Dufour's gland activity of workers. The diameter of the gland and the secretory cell activity increased with increasing oocyte size in the ovary. Regressive conditions of the gland were observed, which are probably related to increasing worker age. To elucidate the production and releasing process of the secretion and to establish its precise function, a comparative analysis of the secretion process of the Dufour's gland of queens and workers is needed.

Morphological changes of Sertoli cells during the male reproductive cycle of the teleost Piaractus mesopotamicus (Holmberg, 1887)

Realizou-se uma investigação das mudanças histológicas e ultra-estruturais das células de Sertoli durante o ciclo reprodutivo de machos de Piaractus mesopotamicus. Os resultados mostraram que o desenvolvimento das células de Sertoli está estritamente relacionado à maturação das células gaméticas. Portanto, as células de Sertoli têm algum papel na maturação das células germinativas durante o ciclo reprodutivo dessa espécie, talvez formando um tecido de sustentação para os cistos espermatogênicos em desenvolvimento, ajudando a reorganização testicular para um novo ciclo reprodutivo, além de outras possíveis funções discutidas no texto.

The reproductive hiology and cycle of Rioraja agassizi (Muller and Henle, 1841) (Chondrichthyes : Rajidae) in southeastern Brazil, SW Atlantic Ocean

Specimens of Rioraja agassizi were collected Lit Guaruja pier, São Paulo State, Brazil, from March 2005 to March 2006. A total of: 275 males were captured. Based on the analysis of the clasper length, gonad weight, clasper gland length, alar thorns and lobule diameter, the size-at-maturity was estimated to be 32 cm. There were 1049 females in the record. Size-at-maturity was calculated in 40 cm. Sexual resting females were observed. Gonadosomatic and hepatosomatic indexes varied significantly in both sexes throughout the year. However, ovulation, egg-laying and presence of sperm in the seminal vesicle were observed all year round. For this reason, an annual cycle with at least one peak in the sexual activity is proposed for this species.

Biological cycle of Lorryia formosa (Acari, Tydeidae) on rubber tree leaves: A case of thelytoky

Lorryia formosa Cooreman has been collected on many different host plants around the world. The biological cycle of this species was studied at 28 degrees C with mites collected from a rubber tree crop. The life table was constructed based on sixty individuals. The average lifetime was 37.43 +/- 20.23 (SE) days, and the r(m) was 0.08. The sex ratio was totally female biased, and unfertilized eggs developed into females. This is the first record of thelytoky in Tydeoidea proved by rearing.

Seasonal metabolic depression, substrate utilisation and changes in scaling patterns during the first year cycle of tegu lizards (Tupinambis merianae)

The tegus increase in body mass after hatching until early autumn, when the energy intake becomes gradually reduced. Resting rates of oxygen consumption in winter drop to 20% of the values in the active season (Vo(2)=0.0636 ml g(-1) h(-1)) and are nearly temperature insensitive over the range of 17-25degreesC (Q(10)=1.55). During dormancy, plasma glucose levels are 60% lower than those in active animals, while total protein, total lipids and beta-hydroxybutyrate are elevated by 24%, 43% and 113%, respectively. In addition, a significant depletion of liver carbohydrate (50%) and of fat deposited in the visceral fat bodies (24%) and in the tail (25%) and a slight loss of skeletal muscle protein (14%) were measured halfway through the inactive period. Otherwise, glycogen content is increased 4-fold in the brain and 2.3-fold in the heart of dormant lizards, declining by the onset of arousal. During early arousal, the young tegus are still anorexic, although Vo(2) is significantly greater than winter rates. The fat deposits analysed are further reduced (62% and 45%, respectively) and there is a large decrease in tail muscle protein (50%) together with a significant increase in glycogen (2-3-fold) and an increase in plasma glucose (40%), which suggests a role for gluconeogenesis as a supplementary energy source in arousing animals. No change is detectable in citrate synthase activity, but beta-hydroxyacyl CoA dehydrogenase activities are strongly affected by season, reaching a Mold and 5-fold increase in the liver tissue of winter and arousing animals, respectively, and becoming reduced by half in skeletal muscle and heart of winter animals compared with late fall or spring active individuals. From hatching to late autumn, the increase of the fat body mass relatively to body mass is disproportionate (b=1.44), and the mass exponent changes significantly to close to 1.0 during the fasting period. The concomitant shift in the Vo(2) mass exponent in early autumn (b=0.75) to values significantly greater than 1.0 in late autumn and during winter dormancy indicates an allometric effect on the degree of metabolic depression related to the size of the fat stores and suggests greater energy conservation in the smaller young.

Germ Cell Dynamics during the Annual Reproductive Cycle of Dendropsophus minutus (Anura: Hylidae)

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