Effect of supplementation of green tea polyphenols on the developmental competence of bovine oocytes in vitro

The objective of the present study was to examine the effect of green tea polyphenols (GTPs) supplementation during in vitro maturation, in vitro fertilization, and in vitro culture on the developmental competence of bovine oocytes. Cumulus-oocyte complexes aspirated from the ovaries were matured in vitro (38.5ºC for 24 h) and fertilized (38.5ºC for 15-18 h) and embryos were cultured (38.5ºC for 192 h) in a defined conditioned medium with or without GTPs supplementation. The GTPs used in the present study contained 99% catechin derivatives, with the major components being 50% (-)-epigallocatechin gallate, 22% (-)-epicatechin gallate, 18% (-)-epigallocatechin, and 10% (-)-epicatechin. Four replicate trials were done for each type of experiment. GTPs supplementation (15 µM) of the maturation medium led to a significant increase in the rate of blastocyst formation (34.0 vs 21.4%, P < 0.05). However, the rate of blastocyst formation was not improved when higher GTPs concentrations (20 or 25 µM) were added to the in vitro maturation medium. During in vitro fertilization, supplementation with higher GTPs concentrations (20 or 25 µM) significantly reduced the rate of blastocyst formation (P < 0.05). Supplementation of the culture medium with 15 µM GTPs improved the rate of blastocyst formation, while higher GTPs concentrations (25 µM) significantly reduced embryo development (P < 0.05). In conclusion, these results demonstrate that supplementation with GTPs at low concentration (15 µM) during in vitro maturation and in vitro culture improved the developmental competence of bovine oocytes.

Effect of conditioned medium of mesenchymal stem cells on the in vitro maturation and subsequent development of mouse oocyte

Mesenchymal stem cells (MSCs) secrete a variety of cytokines and growth factors in addition to self-renewal and multiple forms of differentiation. Some of these secreted bioactive factors could improve meiotic maturation in vitro and subsequent embryo developmental potential. The aim of the present study was to determine whether in vitro maturation (IVM) of mouse oocyte with or without cumulus cells could be improved by contact with conditioned medium (CM) of MSCs as well as the efficiency of CM to support follicular growth and oocyte maturation in the ovarian organ of mice cultured on soft agar. The developmental potential of matured oocyte was assessed by blastocyst formation after in vitro fertilization (IVF). Germinal vesicle stage oocytes with or without cumulus cells were subjected to IVM in either CM, Dulbecco's modified Eagle's medium (DMEM), α-minimum essential medium (α-MEM) or human tubal fluid (HTF). Approximately 120 oocytes were studied for each medium. CM produced a higher maturation rate (91.2%) than DMEM (54.7%), α-MEM (63.5%) and HTF (27.1%). Moreover, CM improved embryo development to blastocyst stage significantly more than DMEM and HTF (85 vs 7% and 41.7%, respectively) but there was no significant difference compared with α-MEM (85 vs 80.3%). The behavior of cortical granules of IVM oocytes cultured in CM revealed cytoplasmic maturation. Moreover, CM also supported preantral follicles growth well in organotypic culture on soft agar resulting in the maturation of 60% of them to developmentally competent oocytes. The production of estrogen progressively increased approximately 1-fold every other day during organ culture, while a dramatic 10-fold increase in progesterone was observed 17 h after human chorionic gonadotropin stimulus at the end of culture. Thus, CM is an effective medium for preantral follicle growth, oocyte maturation, and sequential embryo development.

Diversity of 16S rRNA genes from bacteria of sugarcane rhizosphere soil

Sugarcane is an important agricultural product of Brazil, with a total production of more than 500 million tons. Knowledge of the bacterial community associated with agricultural crops and the soil status is a decisive step towards understanding how microorganisms influence crop productivity. However, most studies aim to isolate endophytic or rhizosphere bacteria associated with the plant by culture-dependent approaches. Culture-independent approaches allow a more comprehensive view of entire bacterial communities in the environment. In the present study, we have used this approach to assess the bacterial community in the rhizosphere soil of sugarcane at different times and under different nitrogen fertilization conditions. At the high taxonomic level, few differences between samples were observed, with the phylum Proteobacteria (29.6%) predominating, followed by Acidobacteria (23.4%), Bacteroidetes (12.1%), Firmicutes (10.2%), and Actinobacteria (5.6%). The exception was the Verrucomicrobia phylum whose prevalence in N-fertilized soils was approximately 0.7% and increased to 5.2% in the non-fertilized soil, suggesting that this group may be an indicator of nitrogen availability in soils. However, at low taxonomic levels a higher diversity was found associated with plants receiving nitrogen fertilizer. Bacillus was the most predominant genus, accounting for 19.7% of all genera observed. Classically reported nitrogen-fixing and/or plant growth-promoting bacterial genera, such as Azospirillum, Rhizobium, Mesorhizobium, Bradyrhizobium, and Burkholderia were also found although at a lower prevalence.

Aspects of energetic substrate metabolism of in vitro and in vivo bovine embryos

Although the metabolism of early bovine embryos has not been fully elucidated, several publications have addressed this important issue to improve culture conditions for cattle reproductive biotechnologies, with the ultimate goal of producing in vitro embryos similar in quality to those developing in vivo. Here, we review general aspects of bovine embryo metabolism in vitro and in vivo, and discuss the use of metabolic analysis of embryos produced in vitro to assess viability and predict a viable pregnancy after transference to the female tract.