Under water discharge in bubbles in very low conductive solutions

This contribution presents experimental results obtained with underwater electric discharge created in rising gas bubbles. This discharge configuration is relatively new, and combines both gas and liquid phase discharges. The properties and mechanism of bubble discharge generation were investigated using a single pulsed high voltage. The electric discharge was generated in a pin-to-plate electrode configuration submerged in deionized water with conductivity of 2.0–5.0 μS/m. The gas bubbles were formed by injecting the gas through a glass filter disc at the bottom of the water tank. Air and helium were used as inlet gas. A spark gap pulse generator triggered the single negative high voltage pulses with rise times below 10 ns and peak voltages of 15–20 kV. The bubble position at the moment of high voltage application was accidental. The measured spectra were qualitatively reproducible, but significant quantitative differences were observed. We observed two types of discharge inside the bubble: delayed and direct spark discharge. The emission spectra of these two discharge kinds were qualitatively very similar

Importance of Supplementation during In Vitro Production of Livestock Animals

Increasing infertility is one of the most serious health problems of today. Over the past few years, we have had the opportunity to follow the progress of technologies focused on the production of embryos in vitro (i.e., in vitro fertilization and intracytoplasmic sperm injection, genetic engineering, or somatic cell nuclear transfer. Oocyte maturation is one of the most important processes in the production of embryos in vitro. Despite recent progress in this field, the developmental competence of in vitro generated oocytes is significantly lower than in vivo. In the last few years, a large number of studies dealing with the improvement of in vitro conditions for embryo culture have been published. These results have huge application potential in the reproduction of farm animals as well as in human medicine. Incorporating various elements, such as serum, hormones, growth factors, and antioxidants, can affect not only oocyte maturation or embryo culture but also an oocyte/embryo quality. The aim of this chapter is to summarize the most important types of supplementations of maturation and culture media and their impact on the improvement of in vitro oocyte and embryo production of farm animals

Mechanisms of FSH- and Amphiregulin-Induced MAP Kinase 3/1 Activation in Pig Cumulus-Oocyte Complexes During Maturation In Vitro

The maturation of mammalian oocytes in vitro can be stimulated by gonadotropins (follicle-stimulating hormone, FSH) or their intrafollicular mediator, epidermal growth factor (EGF)-like peptide—amphiregulin (AREG). We have shown previously that in pig cumulus-oocyte complexes (COCs), FSH induces expression and the synthesis of AREG that binds to EGF receptor (EGFR) and activates the mitogen-activated protein kinase 3/1 (MAPK3/1) signaling pathway. However, in this study we found that FSH also caused a rapid activation of MAPK3/1 in the cumulus cells, which cannot be explained by the de novo synthesis of AREG. The rapid MAPK3/1 activation required EGFR tyrosine kinase (TK) activity, was sensitive to SRC proto-oncogene non-receptor tyrosine kinase (SRC)-family and protein kinase C (PKC) inhibitors, and was resistant to inhibitors of protein kinase A (PKA) and metalloproteinases. AREG also induced the rapid activation of MAPK3/1 in cumulus cells, but this activation was only dependent on the EGFR TK activity. We conclude that in cumulus cells, FSH induces a rapid activation of MAPK3/1 by the ligand-independent transactivation of EGFR, requiring SRC and PKC activities. This rapid activation of MAPK3/1 precedes the second mechanism participating in the generation and maintenance of active MAPK3/1—the ligand-dependent activation of EGFR depending on the synthesis of EGF-like peptides

An Interplay between Epigenetics and Translation in Oocyte Maturation and Embryo Development: Assisted Reproduction Perspective

Germ cell quality is a key prerequisite for successful fertilization and early embryo development. The quality is determined by the fine regulation of transcriptomic and proteomic profiles, which are prone to alteration by assisted reproduction technology (ART)-introduced in vitro methods. Gaining evidence shows the ART can influence preset epigenetic modifications within cultured oocytes or early embryos and affect their developmental competency. The aim of this review is to describe ART-determined epigenetic changes related to the oogenesis, early embryogenesis, and further in utero development. We confront the latest epigenetic, related epitranscriptomic, and translational regulation findings with the processes of meiotic maturation, fertilization, and early embryogenesis that impact the developmental competency and embryo quality. Post-ART embryo transfer, in utero implantation, and development (placentation, fetal development) are influenced by environmental and lifestyle factors. The review is emphasizing their epigenetic and ART contribution to fetal development. An epigenetic parallel among mouse, porcine, and bovine animal models and human ART is drawn to illustrate possible future mechanisms of infertility management as well as increase the awareness of the underlying mechanisms governing oocyte and embryo developmental complexity under ART conditions

Chemical efficiency of H2O2 production and decomposition of organic compounds under action of DC underwater discharge in gas bubbles

A dc underwater discharge generated in gas bubbles (air, Ar, He, and N-2) in a NaH2PO4 center dot 2H(2)O solution is studied. It is shown that the maximal concentration of hydrogen peroxide produced in the discharge does not depend on gas composition. The energy efficiency of H2O2 production is, however, gas dependent, and the highest value of 2.95 g/kWh is obtained for air. The decomposition efficiency of the Direct Blue 106 dye, which is used as a model organic pollutant at an initial concentration of 20 mg/L, increases linearly with current in the investigated range (10-30 mA). A maximal dye decoloration of 65% is observed in a N-2 discharge after 20 min of treatment at a current of 30 mA. Different mechanisms of dye decoloration by plasma are proposed and discussed

Physical properties and chemical efficiency of an underwater dc discharge generated in He, Ar, N2 and air bubbles

A dc excited discharge generated in bubbles (He, Ar, Air, N(2)) in liquid phase is investigated in this work. Voltage/current characteristics and emission spectra of the discharge are recorded in the current range 10-30 mA. Electron density in the discharge is measured from Stark broadening of the H(beta) line and is of the order of 2-6 x 10(20) m(-3), depending on the feed gas. Estimation of electron temperature is carried out based on the balance of charged particles. Gas temperature is estimated by the slope of the Boltzmann plot and by the simulation of the OH band with different T(rot)(1), T(rot)(2) and T(vib). Rotation temperature in the He discharge is 1200 K at I = 10 mA and linearly increases with current up to 1600 K. In the plasma of molecular gases the temperature is higher and almost constant at different currents. Chemical efficiency of the plasma is measured by the production of H(2)O(2) and by the destruction of Direct Blue 106 dye. The highest energy consumption of H(2)O(2) generation is achieved in the air discharge and it decreases up to 50% in the He plasma. Maximal efficiency of dye destruction is observed in the N(2) plasma characterized by an energy consumption of dye decomposition of 0.86 g kWh(-1)

Gene expression analysis of pig cumulus-oocyte complexes stimulated in vitro with follicle stimulating hormone or epidermal growth factor-like peptides

Background: The gonadotropin-induced resumption of oocyte meiosis in preovulatory follicles is preceded by expression of epidermal growth factor (EGF)-like peptides, amphiregulin (AREG) and epiregulin (EREG), in mural granulosa and cumulus cells. Both the gonadotropins and the EGF-like peptides possess the capacity to stimulate resumption of oocyte meiosis in vitro via activation of a broad signaling network in cumulus cells. To better understand the rapid genomic actions of gonadotropins (FSH) and EGF-like peptides, we analyzed transcriptomes of cumulus cells at 3 h after their stimulation. Methods: We hybridized aRNA from cumulus cells to a pig oligonucleotide microarray and compared the transcriptomes of FSH- and AREG/EREG-stimulated cumulus cells with untreated control cells and vice versa. The identified over- and underexpressed genes were subjected to functional genomic analysis according to their molecular and cellular functions. The expression pattern of 50 selected genes with a known or potential function in ovarian development was verified by real-time qRT-PCR. Results: Both FSH and AREG/EREG increased the expression of genes associated with regulation of cell proliferation, cell migration, blood coagulation and extracellular matrix remodeling. FSH alone induced the expression of genes involved in inflammatory response and in the response to reactive oxygen species. Moreover, FSH stimulated the expression of genes closely related to some ovulatory events either exclusively or significantly more than AREG/EREG (AREG, ADAMTS1, HAS2, TNFAIP6, PLAUR, PLAT, and HSD17B7). In contrast to AREG/EREG, FSH also increased the expression of genes coding for key transcription factors (CEBPB, FOS, ID1/3, and NR5A2), which may contribute to the differing expression profiles of FSH- and AREG/EREG-treated cumulus cells. Conclusions: The impact of FSH on cumulus cell gene transcription was higher than the impact of EGF-like factors in terms of the number of cell functions affected as well as the number of over- and underexpressed genes. Both FSH and EGF-like factors overexpressed genes involved in the post-ovulatory switch in steroidogenesis and tissue remodelling. However, FSH was remarkably more efficient in the up-regulation of several specific genes essential for ovulation of matured oocytes and also genes that been reported to play an important role in maturation of cumulus-enclosed oocytes in vitro. Electronic supplementary material The online version of this article (doi:10.1186/s12958-015-0112-2) contains supplementary material, which is available to authorized users