An overview of functional and stereological evaluation of spermatogenesis and germ cell transplantation in fish

Although there are almost thirty-thousand species of fish living in a great variety of habitats and utilizing vast reproductive strategies, our knowledge of morphofunctional and quantitative aspects of testis structure and spermatogenesis is still incipient for this group of vertebrates. In this review, we discuss aspects that are important to better understanding of testis structure and function, and of the development of germ cells (GC) during spermatogenesis. To achieve this, we have recently completed a number of studies presenting morphometric and functional data related to the numbers of GC and Sertoli cells (SC) per each type of spermatogenic cyst, the number of spermatogonial generations, the SC efficiency, and the magnitude of GC loss that normally occurs during spermatogenesis. We also investigated SC proliferation and the relationship of this important event to early spermatogenic cysts. The available data strongly suggest that SC proliferation in sexually mature tilapia is the primary factor responsible for the increase in testis size and for determination of the magnitude of sperm production. The influence of temperature on the duration of spermatogenesis in tilapia was also evaluated and we have used this knowledge to deplete endogenous spermatogenesis in this teleost, in order to develop an experimental system for GC transplantation. This exciting technique results in new possibilities for investigation of spermatogenesis and spermatogonial stem cell biology, creating also an entirely new and promising scenario in biotechnology - transgenic animal production and the preservation of the genetic stocks of valuable animals or endangered species. © Springer Science+Business Media B.V. 2008.

Food selection by a mangrove crab: Temporal changes in fasted animals

The feeding choices of the mangrove crab Ucides cordatus for various mangrove plant leaves (Avicennia schaueriana, Laguncularia racemosa, and Rhizophora mangle) at different ages (mature, senescent pre-abscission, and decomposing leaves) were examined. In a controlled experiment set in a mangrove area, we evaluated crab selection for different plant leaves by analyzing foraging rate (number of leaves with predation marks) and leaf consumption. Crabs were housed individually in plastic containers and after a 3-day fast supplied with leaf fragments every 24 h for 72 h. Uneaten leaves were removed before each new food offering. No food selection was observed in the first day, but after this period, senescent leaves, which have a high polyphenol content, were rejected. On the third day, an interactive effect between plant species and leaf age was shown to affect leaf selection, with mature leaves of A. schaueriana and L. racemosa being more selected than the other treatments. This observation was consistent across crab sexes and ages. Our results show that food selection by this mangrove crab changes through time in fasted animals, suggesting that this variable must be controlled in food preference studies. © 2012 Springer Science+Business Media B.V.

Chlamydophila psittaci infections in hyacinth macaws (anodorhynchus hyacinthinus) confiscated in Brazil

The hyacinth macaw (Anodorhynchus hyacinthinus) is the largest species of psittacine birds. It is considered endangered and illegal trade is one of the main factors involved in its decline. In this study, 26 hyacinth macaws maintained under poor husbandry conditions and destined for the illegal trade were confiscated in São Paulo State, Brazil. These birds were evaluated for the presence of antibodies against Chlamydophila psittaci by complement fixation test and C. psittaci DNA by seminested polymerase chain reaction. Results showed that 65.4% of the macaws were positive for at least one test. Birds with subclinical infections can shed chlamydiae intermittently over long periods, contributing to the dissemination of the agent. Global trade is one of the most important drivers of disease emergence. The high percentage of positive samples in this study emphasizes the potential risk that the illegal trade of wild birds represents for both human and animal health. Copyright 2013 by American Association of Zoo Veterinarians.

Alterações hematológicas e bioquímicas em uma população de Phrynops geoffroanus (Schweigger, 1812) em reposta a estressores ambientes

Pós-graduação em Genética - IBILCE

Análise citogenética clássica e molecular em Chelonoidis carbonaria e Phrynops geoffroanus (Testudines)

Pós-graduação em Genética - IBILCE

Contribuição do estudo ultrassonográfico (Modo e Doppler) de órgãos abdominais em gatos do mato (Leopardus tigrinus) híbridos: valores de referência

Pós-graduação em Medicina Veterinária - FMVZ

Compounds used to produce cloned animals are genotoxic and mutagenic in mammalian assays in vitro and in vivo

The compounds 6-dimethylaminopurine and cycloheximide promote the successful production of cloned mammals and have been used in the development of embryos produced by somatic cell nuclear transfer. This study investigated the effects of 6-dimethylaminopurine and cycloheximide in vitro, using the thiazolyl blue tetrazolium bromide colorimetric assay to assess cytotoxicity, the trypan blue exclusion assay to assess cell viability, the comet assay to assess genotoxicity, and the micronucleus test with cytokinesis block to test mutagenicity. In addition, the comet assay and the micronucleus test were also performed on peripheral blood cells of 54 male Swiss mice, 35 g each, to assess the effects of the compounds in vivo. The results indicated that both 6-dimethylaminopurine and cycloheximide, at the concentrations and doses tested, were cytotoxic in vitro and genotoxic and mutagenic in vitro and in vivo, altered the nuclear division index in vitro, but did not diminish cell viability in vitro. Considering that alterations in DNA play important roles in mutagenesis, carcinogenesis, and morphofunctional teratogenesis and reduce embryonic viability, this study indicated that 6-dimethylaminopurine and cycloheximide utilized in the process of mammalian cloning may be responsible for the low embryo viability commonly seen in nuclear transfer after implantation in utero.

Immunocastration improves carcass traits and beef color attributes in Nellore and Nellore x Aberdeen Angus crossbred animals finished in feedlot

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

Molecular identification of trypanosomatids in wild animals

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

Biogeography, vicariance and conservation of snakes of the neglected and endangered Caatinga region, north-eastern Brazil

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

Variabilidade genética e estruturação populacional do Bicudinho-do-brejo-paulista, Formicivora paludicola (aves: Thamnophilidae): uma espécie criticamente ameaçada do estado de São Paulo

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

Detection of antibodies to Toxoplasma gondii in wild animals in Brazil

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

Respiratory manifestations of panic disorder in animals and humans: A unique opportunity to understand how supramedullary structures regulate breathing

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

Fire and the reproductive phenology of endangered Madagascar sclerophyllous tapia woodlands

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Arthropod-borne pathogens circulating in free-roaming domestic cats in a zoo environment in Brazil

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