Tony Silveira

Melatonin delivery by nanocapsules during in vitro bovine oocyte maturation decreased the reactive oxygen species of oocytes and embryos

In this work, a promising approach to increase the advantageous properties of melatonin through its encapsulation into lipid-core nanocapsules (LNC) was examined. Oocytes were treated during in vitro maturation with non-encapsulated melatonin (Mel), melatonin-loaded lipid-core nanocapsules (Mel-LNC), and unloaded LNC. Cytotoxicity, meiotic maturation rate, development to the blastocyst stage, reactive oxygen species (ROS) and glutathione levels, mean cell number and apoptotic cell/blastocyst, and mRNA quantification were evaluated. Both Mel and Mel-LNC enhanced in vitro embryo production, however, Mel-LNC proved to be more effective at decreasing ROS levels and the apoptotic cell number/blastocyst, increasing the cleavage and blastocyst rates, up-regulating the GPX1 and SOD2 genes, and down-regulating the CASP3 and BAX genes. Mel-LNC could penetrate into oocytes and remain inside the cells until they reach the blastocyst stage. In conclusion, when melatonin was encapsulated in LNC and applied during in vitro oocyte maturation, some quality aspects of the blastocysts were improved.

Effects of chitosan-coated lipid-core nanocapsules on bovine sperm cells

Toxicology studies have a pivotal role for selection of new nanosystems. As lipid-core nanocapsules (LNC) rise as a potential system not only for drug delivery but also for immunotherapy and gene therapy, the demand for models of toxic screening increases, and sperm arises as a promising model due to the easiness to evaluate its viability parameters. LNCs were coated with chitosan, chitosan-coated lipid-core nanocapsules (LNC-CS), in order to modify the nanocapsule surface. We evaluated the toxicity of LNC and LNC-CS after incubation with bovine sperm in different concentrations (2.5%, 5%, 10%, 20%, 40% and 80%) (v/v) and periods of exposure (0h and 1h). CASA parameters and flow cytometry assays were performed to assess LNC and LNC-CS effects. The results corroborated with previous studies indicating that there is no toxicity from LNCs and LNC-CS below 40% (v/v) concentration.

Pseudolynchia canariensis(Diptera: Hippoboscidae): distribution pattern and phoretic association with skin mites and chewing lice ofColumba livia(Aves: Columbidae)

The examination of 145 specimens of Pseudolynchia canariensis (74 males and 71 females) from 31 specimens of Columba livia captured between March and April of 2012 in the municipality of Pelotas, southern Brazil, revealed an aggregated distribution of hippoboscid flies. Prevalence and mean intensity of infestation were higher on younger hosts. Approximately 30% of hippoboscid flies exhibited phoretic associations with skin mites of the families Epidermoptidae and Cheyletidae as well as with chewing lice of the family Philopteridae. Myialges anchora and Ornithocheyletia hallae skin mites exhibited aggregated distributions. On P. canariensis only female skin mites were observed, M. anchora being the most prevalent and abundant. The abdominal ventral surface, between the metathorax and the first abdominal tergite and the ventral surface of wings of hippoboscid flies were the preferred regions for attachment by skin mites, whereas Columbicola columbae was observed attached to the mesotibia of one hippoboscid fly.

Gene and Blood Analysis Reveal That Transfer from Brackish Water to Freshwater Is Less Stressful to the Silverside Odontesthes humensis

Silversides are fish that inhabit marine coastal waters, coastal lagoons, and estuarine regions in southern South America. The freshwater (FW) silversides have the ability to tolerate salinity variations. Odontesthes humensis have similar habitats and biological characteristics of congeneric O. bonariensis, the most studied silverside species and with great economic importance. Studies revealed that O. bonariensis is not fully adapted to FW, despite inhabiting hyposmotic environments in nature. However, there is little information about stressful environments for cultivation of silverside O. humensis. Thus, the aim of this study was to evaluate the stress and osmoregulation responses triggered by the osmotic transfers on silverside O. humensis. Silversides were acclimated to FW (0 ppt) and to brackish water (BW, 10 ppt) and then they were exposed to opposite salinity treatment. Silverside gills and blood were sampled on pre-transfer (D0) and 1, 7, and 15 days (D1, D7, and D15) after changes in environmental salinity, the expression levels of genes atp1a3a, slc12a2b, kcnh1, and hspa1a were determined by quantitative reverse transcription-PCR for evaluation of osmoregulatory and stress responses. Furthermore, glycemia, hematocrit, and osmolality were also evaluated. The expression of atp1a3a was up- and down-regulated at D1 after the FW–BW and BW–FW transfers, respectively. Slc12a2b was up-regulated after FW–BW transfer. Similarly, kcnh1 and hspa1a were up-regulated at D1 after the BW–FW transfer. O. humensis blood osmolality decreased after the exposure to FW. It remained stable after exposure to BW, indicating an efficient hyposmoregulation. The glycemia had a peak at D1 after BW–FW transfer. No changes were observed in hematocrit. The return to the pre-transfer levels at D7 after the significant increases in responses of almost all evaluated molecular and blood parameters indicated that this period is enough for acclimation to the experimental conditions. In conclusion, our results suggest that BW–FW transfer is more stressful to O. humensis than FW–BW transfer and the physiology of O. humensis is only partially adapted to FW.

Flow cytometric sex sorting affects CD4 membrane distribution and binding of exogenous DNA on bovine sperm cells

Bovine sex-sorted sperm have been commercialized and successfully used for the production of transgenic embryos of the desired sex through the sperm-mediated gene transfer (SMGT) technique. However, sex-sorted sperm show a reduced ability to internalize exogenous DNA. The interaction between sperm cells and the exogenous DNA has been reported in other species to be a CD4-like molecule-dependent process. The flow cytometry-based sex-sorting process subjects the spermatozoa to different stresses causing changes in the cell membrane. The aim of this study was to elucidate the relationship between the redistribution of CD4-like molecules and binding of exogenous DNA to sex-sorted bovine sperm. In the first set of experiments, the membrane phospholipid disorder and the redistribution of the CD4 were evaluated. The second set of experiments was conducted to investigate the effect of CD4 redistribution on the mechanism of binding of exogenous DNA to sperm cells and the efficiency of lipofection in sex-sorted bovine sperm. Sex-sorting procedure increased the membrane phospholipid disorder and induced the redistribution of CD4-like molecules. Both X-sorted and Y-sorted sperm had decreased DNA bound to membrane in comparison with the unsorted sperm; however, the binding of the exogenous DNA was significantly increased with the addition of liposomes. Moreover, we demonstrated that the number of sperm-bound exogenous DNA was decreased when these cells were preincubated with anti-bovine CD4 monoclonal antibody, supporting our hypothesis that CD4-like molecules indeed play a crucial role in the process of exogenous DNA/bovine sperm cells interaction.

How do seasonality and host traits influence the distribution patterns of parasites on juveniles and adults of Columba livia

Parasites may influence host fitness and consequently exert a selective pressure on distinct phenotypes of the host population. This pressure can result in an evolutionary response, maintaining only individuals with certain traits in the population. The present study was aimed at identifying the morphological characteristics of juveniles and adults of Columba livia that may influence the distribution patterns of lice, Pseudolynchia canariensis and Haemoproteus columbae and how the populations of these parasites vary throughout the seasons of the year. Between July 2012 and July 2014, 377 specimens of C. livia were captured. We observed a significant increase in the mean intensities of infestation by pigeon flies and lice, as well as in species richness of ectoparasites during the warmest seasons, suggesting a reproductive synchrony between ectoparasites and host species. Bill length, body mass, and body length did not affect the infestation levels of ectoparasites on adults and juveniles of C. livia with three distinct plumage colors. In juveniles, plumage color affected only the mean intensity of infestation by lice, with Spread individuals as the most infested. This indicates that melanin in feathers was not an effective barrier against ectoparasites.

Verificação da transmissão vertical de Neospora spp. em equinos

The genre protozoan Neospora is recognized as causing reproductive disorders and miscarriages in cattle. Among the horses little is known about the effects of infection by these protozoa. It is currently accepted that the effects of infection by Neospora hughesi in horses may occur in the central nervous system, and effects of Neospora caninum infection occur in the reproductive system of mares. The present study examined the presence of class immunoglobulin G in blood serum of a population of brood mares and their foals before colostrum ingestion. For this assignment was employed indirect immunofluorescence assay (IFA) using as antigen tachyzoites of Neospora caninum, the initial dilution employed in sera of the mares was 1:50 and dilution in the serum of foals was 1:16. Were assisted 78 deliveries and all foals had their blood serum collected immediately after birth. The presence of antibodies against Neospora spp. found in mares was 50 (64%) and 32 (41%) foals were positive. Of the 50 mares that had antibodies to Neospora spp. 24 generated positive foals. Among the 28 mares unreacted eight gave birth to foals positive. Having the results we can conclude that vertical transmission occurred Neospora spp. researched in horses.

Evaluation of Reference Genes to Analyze Gene Expression in Silverside Odontesthes humensis Under Different Environmental Conditions

Some mammalian reference genes, which are widely used to normalize the qRT-PCR, could not be used for this purpose due to its high expression variation. The normalization with false reference genes leads to misinterpretation of results. The silversides (Odontesthes spp.) has been used as models for evolutionary, osmoregulatory and environmental pollution studies but, up to now, there are no studies about reference genes in any Odontesthes species. Furthermore, many studies on silversides have used reference genes without previous validations. Thus, present study aimed to was to clone and sequence potential reference genes, thereby identifying the best ones in Odontesthes humensis considering different tissues, ages and conditions. For this purpose, animals belonging to three ages (adults, juveniles, and immature) were exposed to control, Roundup®, and seawater treatments for 24 h. Blood samples were subjected to flow-cytometry and other collected tissues to RNA extraction; cDNA synthesis; molecular cloning; DNA sequencing; and qRT-PCR. The candidate genes tested included 18s, actb, ef1a, eif3g, gapdh, h3a, atp1a, and tuba. Gene expression results were analyzed using five algorithms that ranked the candidate genes. The flow-cytometry data showed that the environmental challenges could trigger a systemic response in the treated fish. Even during this systemic physiological disorder, the consensus analysis of gene expression revealed h3a to be the most stable gene expression when only the treatments were considered. On the other hand, tuba was the least stable gene in the control and gapdh was the least stable in both Roundup® and seawater groups. In conclusion, the consensus analyses of different tissues, ages, and treatments groups revealed that h3a is the most stable gene whereas gapdh and tuba are the least stable genes, even being considered two constitutive genes.