Effects of Prostaglandins E2 and F2alpha on the in vitro maturation of bovine oocytes.

We aimed to elucidate the effects of PGE2 and PGF2a on the in vitro maturation (IVM) of bovine oocytes. First, cumulus-oocyte complexes were matured in the media supplemented with or without PGE2, PGF2a, or PGE2 plus PGF2a for the final 24, 12, or 6 h of culture. Then, the cumulus-oocyte complexes were matured in the absence or presence of a PG endoperoxide synthase 2 (PTGS2) enzyme inhibitor (NS398) supplemented with PGE2, PGF2a, or PGE2 plus PGF2a. Finally, the expression of genes associated with PGs activity in cumulus cells (PTGS2, PG E-synthase-1 [PTGES1], and aldo-keto reductase 1 [AKR1B1]) or oocytes (receptors for PGE2 [PTGER2] and PGF2a [PTGFR]) of different competencies was quantified. Supplementation of the IVM medium with PGs did not improve in vitro embryo production or embryo quality (P > 0.05). During maturation, the relative abundance of PTGS2 transcripts increased (P < 0.05) only in the less-competent group, whereas those of PTGES1 increased in the less-competent and in the more-competent groups. Conversely, AKR1B1 expression decreased only in the less-competent group (P < 0.05). Receptors for the PGE2 and PGF2a genes were very low or undetectable in oocytes. In conclusion, PGE2 and PGF2a are not recommended for media supplementation during maturation because they have no effect on embryo development. Although genes related to PGs activity are differentially expressed in cumulus cells of cumulus-oocyte complexes of different competence during maturation, the expression of PGE2 and PGF2a receptor genes was either not detectable or was detected at low levels in oocytes

Custos logísticos agroindustriais: avaliação do escoamento da soja em grão do Mato Grosso para o mercado externo Agribusiness logistics costs: evaluation of Mato Grosso state's soybean export

O objetivo deste trabalho é propor e aplicar um modelo de cálculo de custo logístico total para produtos agroindustriais brasileiros voltados para a exportação. O modelo é aplicado para a soja em grão produzida no Mato Grosso e exportada pelo porto de Santos. As avaliações contemplam fluxos de escoamento com rotas unimodais e intermodais. Do ponto de vista teórico, o modelo proposto contempla algumas variáveis comumente negligenciadas em análises deste tipo. Este é, por exemplo, o caso das variáveis ligadas à tributação. Do ponto de vista dos resultados empíricos resultantes da aplicação do modelo, o trabalho mostra que, devido a uma série de fatores e contrariando grande parte da bibliografia disponível sobre o assunto, nem sempre é vantajoso para o produtor brasileiro de soja do Mato Grosso escoar sua produção por alternativas intermodais. Algumas sugestões para trabalhos futuros nesta área são apresentadas ao final do artigo.<br>The objective of this study is to propose and implement a theoretical framework to calculate the total logistics costs of Brazilian agribusiness products meant for export. The framework was applied to soybeans that are produced in Mato Grosso and exported from the port of Santos. The analyses include unimodal and intermodal routes. From a theoretical viewpoint, the proposed framework includes some variables that are often underestimated in this kind of analysis, such as tax variables. With regard to the empirical results from implementing the framework, the study shows that due to a number of factors and contrary to much of the literature available on the subject, it is not always advantageous for the Mato Grosso soybeans producers to transport their production using intermodal alternatives. Future research suggestions are included at the end of the paper