911 resultados para maternal and paternal effects
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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We evaluated genetic and environmental factors affecting age at first farrowing of sows in the Brazilian southeast. For this purpose, 466 observations regarding the age at first farrowing were made for Dalland-C40 (c) animals belonging to two herds. The effects of the environmental factors on this trait were assessed by means of a model that included, as random effects, the influence of the sow's father and mother and, as fixed effects, the influence the year of birth, the herd and the birth season, along with the covariable litter size at birth. The variance components were estimated using the derivative-free restricted maximum likelihood method. The estimated mean was 354.8 +/- 25.87 days, with a coefficient of variation of 7.29%. Significant effects on the trait were observed for the herd, the year and the season of birth; but a linear effect of litter size at birth on the age at first farrowing was not observed. The boar did not significantly contribute to the variation occurring among the sows, whereas the sow's mother caused significant variation. The heritability estimate for the age at first farrowing was 0.44 +/- 0.15, which is considered high. We concluded that herd effect and year and season of birth should be taken into consideration for an accurate genetic comparison; consequently, the animals should be joined into contemporary groups.
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O pepino (Cucumis sativus L.) é, dentre os produtos hortícolas, um dos mais visados para o cultivo em estufas no Brasil devido ao ciclo vegetativo curto e ao elevado valor econômico no período da entressafra. Estudou-se, em condições de ambiente protegido, a influência de diferentes cores de cobertura plástica de solo no florescimento e na produção de pepino híbrido 'Yoshinari' enxertado ou não sobre abóbora híbrida 'Ikky'. Os tratamentos de cobertura foram: preto, preto pintado de branco, verde, e sem cobertura. Os tratamentos cobertos com plástico e sem enxertia apresentaram florescimento com distribuição mais uniforme na planta. O número de flores foi superior no tratamento preto/branco enxertado. Para as plantas não enxertadas, todas as coberturas favoreceram o florescimento. A enxertia favoreceu o florescimento somente para os tratamentos com plástico preto ou verde. A fixação dos frutos aumentou pelo uso de cobertura plástica, mas a enxertia não teve influência. A distribuição uniforme do florescimento manteve-se na frutificação apenas para os tratamentos com plantas enxertadas e cobertura do solo com plástico preto ou verde. Tanto o uso de cobertura plástica quanto a enxertia favoreceram a colheita precoce. Os frutos de melhor qualidade e as maiores produções, em número de frutos, foram obtidos nos tratamentos preto e preto/branco, não enxertados. A enxertia 'Yoshinari'/'Ikky' provocou o aparecimento de frutos mais grossos e menores, fora do padrão de comercialização.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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According to clinical and pre-clinical studies, oxidative stress and its consequences may be the cause or, at least, a contributing factor, to a large number of neurodegenerative diseases. These diseases include common and debilitating disorders, characterized by progressive and irreversible loss of neurons in specific regions of the brain. The most common neurodegenerative diseases are Parkinson's disease, Huntington's disease, Alzheimer's disease and amyotrophic lateral sclerosis. Coenzyme Q(10) (CoQ(10)) has been extensively studied since its discovery in 1957. It is a component of the electron transportation chain and participates in aerobic cellular respiration, generating energy in the form of adenosine triphosphate (ATP). The property of CoQ(10) to act as an antioxidant or a pro-oxidant, suggests that it also plays an important role in the modulation of redox cellular status under physiological and pathological conditions, also performing a role in the ageing process. In several animal models of neurodegenerative diseases, CoQ(10) has shown beneficial effects in reducing disease progression. However, further studies are needed to assess the outcome and effectiveness of CoQ(10) before exposing patients to unnecessary health risks at significant costs.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The isolation and biochemical/enzymatic characterization of an L-amino acid oxidase, Balt-LAAO-I, from Bothrops alternates snake venom, is described. Balt-LAAO-I is an acidic glycoprotein, pI similar to 5.37, homodimeric, M-r similar to 123, 000, whose Nterminal sequence is ADVRNPLE EFRETDYEVL. It displays a high specificity toward hydrophobic and basic amino acids, while deglycosylation does not alter its enzymatic activity. Bait-LAAO-I induces platelet aggregation and shows bactericidal activity against Escherichia coli and Staphylococcus aureus. In addition, this enzyme is slightly hemorrhagic and induces edema in the mouse paw. Bait-LAAO-I is a multifunctional enzyme with promising relevant biotechnological and medical applications. (C) 2004 Elsevier Ltd. All rights reserved.
Differential behavioral and neuroendocrine effects of repeated nicotine in adolescent and adult rats
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Despite the high prevalence of tobacco abuse among adolescents, the neurobiology of nicotine addiction has been studied mainly in adult animals. Repeated administration of this drug to adult rats induces behavioral sensitization. Nicotine activates the HPA axis in adult rats as measured by drug-induced increases in ACTH and corticosterone. Both behavioral sensitization and corticosterone are implicated in drug addiction. We examined the expression of behavioral sensitization induced by nicotine as well as the changes in corticosterone levels after repeated injections of nicotine in adolescent and adult animals. Adolescent and adult rats received subcutaneous (s.c.) injections of saline or 0.4 mg/kg of nicotine once daily for 7 days. Three days after the last injection animals were challenged with saline or nicotine (0.4 mg/kg; s.c.). Nicotine-induced locomotion was recorded in an activity cage. Trunk blood samples were collected in a subset of adolescent and adult rats and plasma corticosterone levels were determined by radioimmunoassay. Adult, but not adolescent, rats expressed behavioral sensitization. Pretreatment with nicotine abolished corticosterone-activating effect of this drug only in adult animals, indicating the development of tolerance at this age. Our results provide evidence that adolescent rats exposed to repeated nicotine display behavioral and neuroendocrine adaptations distinct from that observed in adult animals. (c) 2004 Elsevier B.V. All rights reserved.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The compound SmBa(2)Cu(3)O(7-delta) (SBCO)-obtained by substituting rare-earth Sm for Y in the well-known and most studied YBa(2)Cu(3)O(6+delta) (YBCO)-is potentially attractive to study in order to understand the superconductivity mechanism in physics and in electronic device applications. For SBCO, the possibility of variable stoichiometry and the high mobility of oxygen in CuO(x) planes give rise to a rich phase diagram. This study reports on the effect of heat treatments in an oxygen atmosphere on the anelastic properties of this oxide, in which relaxation processes were observed, attributed to oxygen atom jumps present in the Cu-O planes during the orthorhombic phase.
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The polarization effects of in-plane electric fields and eccentricity on electronic and optical properties of semiconductor quantum rings (QRs) are discussed within the effective-mass approximation. As eccentric rings may appropriately describe real (grown or fabricated) QRs, their energy spectrum is studied. The interplay between applied electric fields and eccentricity is analysed, and their polarization effects are found to compensate for appropriate values of eccentricity and field intensity. The importance of applied fields in tailoring the properties of different nanoscale materials and structures is stressed.