Structural analysis of the embryonic development in Brycon cephalus (Gunther, 1869)

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

Early embryonic death in mares: clinical and hormonal aspects

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

Temporal and morphological differences in post-embryonic differentiation of the mushroom bodies in the brain of workers, queens, and drones of Apis mellifera (Hymenoptera, Apidae)

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

Thermal requirements for the embryonic development of Periplaneta americana (L.) (Dictyoptera: Blattidae) with potential application in mass-rearing of egg parasitoids

The embryonic development of oothecae of Periplaneta americana was evaluated under four different constant temperatures (5, 10, 15, 20, 25, 30, and 35 degrees C and also at different exposure times at <5 degrees C. Their suitability as hosts after the treatment for the parasitoids Evania appendigaster and Aprostocetus hagenowii was also assessed. Temperatures of 5, 10, 15, and 35 degrees C adversely affected the development of the cockroaches, and exposure times to <5 degrees C longer than 5 days sufficed to kill all the embryos in the oothecae. The lower thermal threshold for complete development of P. americana was estimated to be 6.8 degrees C, with a required total amount of 900.9 degree-days. Cold-killed oothecae were still fit for the development of parasitoids. Parasitism rates of A hagenowii were higher than those of E appendigaster, although with lower emergence rates. Our results can be useful in aiding mass-rearing of these parasitoids for biological control programmes of A americana, and may help forecast the time of emergence of nymphs of American cockroaches in infested areas. (C) 2008 Elsevier B.V. All rights reserved.

Post-Embryonic Development of Larvae of the Weaver Ant Camponotus textor (Hymenoptera: Formicidae)

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

Water content and GA(3)-induced embryonic cell expansion explain Euterpe edulis seed germination, rather than seed reserve mobilisation

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

New molecular variants of hypothalamus-pituitary-gonad axis genes and their association with early puberty phenotype in Bos taurus indicus (Nellore)

Endocrine system plays a major role in the control of reproductive functions which are regulated by the hypothalamus-pituitary-gonad axis and its interactions. FSH and LH receptor genes are expressed at the gonads and GnRH receptor gene is expressed at the anterior pituitary gland. Misense mutations of the FSH, LH or GnRH receptors, activating or inactivating their functions in mammals, are potentially useful to allow the understanding of the role of this group of gonadotropins in reproductive phenotypes as early puberty and birth interval length. In the present study, polymorphisms in bovine exon 11 and 3'UTR of LHR, exon 10 and 3'UTR of FSHR and GnRHR genes were characterized with some of them resulting in changes in the aminoacidic chain. These polymorphic sites were found in a Bos taurus indicus (Nellore) female population by means of PCR-SSCP and DNA sequencing. Association between nucleotidic/aminoacidic changes and early puberty were determined by Chi-square analysis. It was found association between FSHR 3'UTR polymorphisms at position 2181, 2248 and 2249 bp and early puberty phenotype (p < 0.05). The presence of these new molecular markers might be considered in further studies to validate its correlation with early puberty or other reproduction associated phenotypes in cattle breeds. (C) 2007 Published by Elsevier B.V.

Structural and ultrastructural analysis of embryonic development of Prochilodus lineatus (Valenciennes, 1836) (Characiforme ; Prochilodontidae)

This survey was performed to characterize the embryogenesis of Prochilodus lineatus. Seven stages of embryo development were identified - zygote, cleavage, blastula, gastrula, segmentation, larval and hatching - after a period of incubation of 22h (24 degrees C) or 14h (28 degrees C). The following cleavage pattern was identified: the first plane was vertical (2 blastomeres); the second was vertical and perpendicular to the first (4 blastorneres); the third was vertical and parallel to the first (4 x 2); the fourth cleavage was vertical and parallel to the second (4 x 4); the fifth was vertical and parallel to the first (4 x 8); and the sixth cleavage was horizontal (64 blastomeres). At the blastula stage (3.0-4.0 h (24 degrees C); 1.66-2.0h (28 degrees C) irregular spaces were detected and periblast structuring was initiated. At the gastrula stage (4.0-8.0 h (24 degrees C); 3.0-6.0 h (28 degrees C) the epiboly, convergence and cell movements, as well as the formation of embryonic layers, had begun. The segmentation stage (10.0-15.0h (24 degrees C); 7.0-10.0h (28 degrees C)) was characterized by a rudimentary formation of organs and systems (somites, optic vesicle and intestinal delimitation). The embryo at the larval stage (16.0-21.0 h (24 degrees C); 11.0-13.0 h (28 degrees C)) showed a free tail, more than 25 somites, an optic vesicle and a ready-to-hatch larval shape. The blastomeres at cleavage stage had disorganized nuclei indicating high mitotic activity. At gastrula, the blastomeres and the periblast had euchromatic nuclei and a large number of mitochondria and vesicles. The yolk was organized into globose sacs, which were dispersed into small pieces prior to absorption.

Effect of thermal conditioning during embryonic development on aspects of physiological responses of broilers to heat stress

The purpose of the present study was to investigate the effect of thermal conditioning, (through exposure to heat stress), during pre-hatch development on some physiological responses of post-hatch broilers to a post-natal heat stress challenge. Exposure to heat stress at this stage, we hope, may possibly induce epigenetic heat adaptation. Incubating eggs were exposed to temperature of 39.0degreesC for 2 h from Day 13 to 17 of incubation. At 33, 35, 37, 39, 41 and 43 d of age, the broilers hatched from these eggs were housed individually in open-circuit respiration cells. The climatic chambers were set to 22degreesC and increased to 30degreesC for 4 h. O-2 consumption and CO2 production of each chicken was monitored continuously in order to calculate the heat production. Blood samples were obtained before and during the 4 h heat stress. Thermal conditioning during incubation did not affect the plasma T-4, corticosterone, glucose, uric acid and CK concentrations. Temperature challenge, decreased plasma T-3 of broilers of both groups but the decrease was greater in pre-conditioned broilers compared with controls. A similar trend was observed for triglycerides. These changes did not affect total heat production. Since decreased T3 and triglyceride levels are part of the mechanisms for thermoregulation, these suggest that thermal conditioning during incubation can improve the broiler chicken capability for thermotolerance at later post-hatch age. (C) 2002 Elsevier B.V. Ltd. All rights reserved.

Effects of Short-term Hyper- and Hypoprolactinaemia on Hormones of the Pituitary, Gonad and -Thyroid Axis and on Semen Quality in Male Beagles

Effects of a short-term hyper- and hypoprolactinaemia on serum concentrations of LH, testosterone and semen quality in six male Beagles were investigated. Blood samples were collected at 3-day intervals for 12 weeks. The time span was divided into five 3-week periods: pre-treatment, metoclopramide (MCP) treatment (0.2 mg/kg orally three times daily), cabergoline (CAB) treatment (5 mu g/kg orally once daily), post-treatment 1 and post-treatment 2. In the latter, only semen characteristics were evaluated. Semen parameters were analyzed once per week during the whole 15-week investigation time. At the end of each period, the effects of a single intravenous injection of thyrotropin-releasing hormone (TRH; 10 mu g/kg) on the secretion of prolactin (PRL), LH, testosterone, thyroid-stimulating hormone and thyroxine (T4) were investigated. Pre-treatment serum PRL concentration increased under MCP (p < 0.05), followed by a decrease under CAB administration (p < 0.05). Luteinizing hormone and testosterone concentrations were not affected. Except for straight-line sperm velocity, semen quality did not differ between collection periods. A single iv TRH injection induced a significant PRL increase at 20 min in all experimental periods except during CAB treatment. Luteinizing hormone and testosterone did not show clear TRH-related changes. Basic T4 levels were significantly reduced after CAB treatment ( p < 0.05). The results of the present study demonstrate that MCP-induced short-term hyperprolactinaemia in male beagles does not seriously affect the hypothalamo-pituitary axis and semen quality.