Influence of the collection technique of prepubertal goat oocytes on in vitro maturation and fertilization

Prepubertal goat ovaries obtained from a slaughterhouse were used to study the influence of the oocyte collection technique (dissection, aspiration and slicing) on the number of oocytes recovered and their capacity for maturation and fertilization in vitro. The oocytes were recovered using 3 techniques, were selected for culture and were classified according to the number of cumulus cell layers. The numbers of oocytes selected per ovary were 1.71, 1.27 and 6.05 for dissection, aspiration and slicing, respectively. The percentages of maturation obtained for slicing (56.9%) were lower than those obtained for dissection and aspiration (69.3 and 72.0%, respectively). The proportion of oocytes with the most cumulus cell layers (complete cumulus) was greatest for oocytes recovered by dissection, but this had no influence on their capacity for nuclear maturation. The total percentage of fertilization was similar for oocytes obtained by dissection and by slicing, but the latter yielded a lower percentage of normal fertilization (29.1 vs 18.2%). Of the oocytes obtained by slicing, no difference was observed in the fertilization rate between oocytes with a partial cumulus and a complete cumulus. The decrease in maturation time from 27 to 25.5 and 24 h did not improve the results for fertilization but caused a decrease in the percentage of nuclear maturation. In conclusion, the recovery of oocytes using the slicing technique yielded more oocytes per ovary than dissection or aspiration, although the in vitro fertilization capacity of oocytes obtained by the slicing method was lower than for oocytes obtained by dissection.     

Aerobic and Anoxic Growth and Nitrate Removal Capacity of a Marine Denitrifying Bacterium Isolated from a Recirculation Aquaculture System

Bacterial biofilters used in marine recirculation aquaculture systems need improvements to enhance nitrogen removal efficiency. Relatively little is known about biofilter autochthonous population structure and function. The present study was aimed at isolating and characterizing an autochthonous denitrifying bacterium from a marine biofilter installed at a recirculation aquaculture system. Colonization of four different media in a marine fish farm was followed by isolation of various denitrifying strains and molecular classification of the most promising one, strain T2, as a novel member of the Pseudomonas fluorescens cluster. This strain exhibits high metabolic versatility regarding N and C source utilization and environmental conditions for growth. It removed nitrate through aerobic assimilatory metabolism at a specific rate of 116.2 mg NO₃-N g dw⁻¹ h⁻¹. Dissimilatory NO₃-N removal was observed under oxic conditions at a limited rate, where transient NO₂-N formed represented 22% (0.17 mg L⁻¹) of the maximum transient NO₂-N observed under anoxic conditions. Dissimilatory NO₃-N removal under anoxic conditions occurred at a specific rate of 53.5 mg NO₃-N g dw⁻¹ h⁻¹. The isolated denitrifying strain was able to colonize different materials, such as granular activated carbon (GAC), Filtralite and Bioflow plastic rings, which allow the development of a prototype bioreactor for strain characterization under dynamic conditions and mimicking fish-farm operating conditions.     

Effect of in vitro and in vivo culture on embryo development from prepubertal goat IVM-IVF oocytes

The aim of this study was to analyze different culture systems on embryo development of prepubertal goat oocytes. We compare (i) the effect of the age of donor (goat) of oocytes on in vitro maturation, fertilization and subsequent embryo development, (ii) the effect of the origin of oviduct cells from coculture of prepubertal goat embryo development, and (iii) the effect of in vivo culture in rabbit oviducts for 1, 2 and 3 days on the development of prepubertal goat embryos produced in vitro. In Experiment 1, at 24 h post-insemination (hpi), oocytes from adult goats were allocated in TCM199 with oviduct cells from adult goats, and oocytes from prepubertal goats were randomly placed in drops with oviduct epithelial cells from adult (aOEC) or prepubertal (pOEC) goats. Cleavage rate and embryo development were evaluated at 48 hpi and after 7 days coculture, respectively. In Experiment 2, at 24 hpi, prepubertal oocytes were allocated in TCM 199 with pOEC. At 40-42 hpi, a group of embryos remained in the coculture (control group), and the rest were transferred to rabbit oviducts (three rabbits for replicate) for culturing in vivo for 24, 48 and 72 h. After these in vivo cultures, embryos were recovered, evaluated and placed in TCM199 with pOEC until Day 8 post-insemination. The maturation, fertilization and blastocyst rates did not differ significantly between oocytes obtained from adult and prepubertal goats. The percentage of blastocysts obtained from prepubertal goat embryos cocultured with aOEC or pOEC was also similar (12.1% versus 12.2%). The transfer of prepubertal goat embryos to rabbit oviducts for 1, 2 and 3 days did not improve the blastocyst rate compared to the control group (9.7, 10.9, 4.1 and 11.5%, respectively). In conclusion, in our conditions, there were no significant differences in embryo development between oocytes obtained from prepubertal and adult goats, and the embryo development from prepubertal goat oocytes were similar in the different culture systems compared.     

Corporate Social Responsibility: A Real Options Approach to the Challenge of Financial Sustainability

BackgroundIn contemporary complex societies, social values like ethics, corporate social responsibility, and being respectful with the environment, among others, are becoming social requirements. Corporations are expected to fulfill them and, according to empirical evidence, an overwhelming majority aspires to good social valuation. At the same time, the maximization of market share value in the long run continues to be the central corporate goal. Making environmental and social expenses compatible with value creation is a central challenge for corporations since it implies the financial sustainability of Corporate Social Responsibility (CSR).

Methods and Results

The value creation capacity of CSR projects, mainly through innovation, is widely acknowledged in economic literature and corporate practice. This fact arouses the need of having a quantitative framework capable of summarizing the value creation capacity of the variables involved in CSR projects. With this aim we build up a sensitivity analysis of real option ratios that studies and quantifies the value creation capacity of CSR projects connected with innovation. Ratio analysis has the advantage of being scale independent. Hence, it furnishes a homogeneous framework to express the interaction of value creation variables and, thus, supports strategic thinking quantitatively. Often, CSR expenses can be regarded as preliminary projects that create the opportunity to undertake a full future project. For them, we obtain the minimum expectations scenario that makes financially sustainable a preliminary project that can be interpreted as a call option. We propose a classification of CSR projects from the decision analysis perspective following a two-fold approach: Their relationship with value creation and their links with existing corporate activities. This classification of CSR projects aims at contributing to choose the best capital budgeting method to study the financial sustainability of the project and identifying those CSR projects that fulfill the required features to be studied from the real options perspective.     

Supplementation with cysteamine during maturation and embryo culture on embryo development of prepubertal goat oocytes selected by the brilliant cresyl blue test

Our previous studies have shown that the addition of 100 mircroM cysteamine to the in vitro maturation (IVM) medium increased the embryo development of prepubertal goat oocytes. The aim of the present study was to evaluate the effect of adding different concentrations of cysteamine to the IVM medium and to the in vitro embryo culture medium (IVC) on the embryo development of prepubertal goat oocytes selected by the brilliant cresyl blue (BCB) test. Oocytes were exposed to BCB and classified as: oocytes with a blue cytoplasm or grown oocytes (BCB+) or oocytes without blue cytoplasm or growing oocytes (BCB-). In Experiment 1, oocytes were matured in a conventional IVM medium supplemented with 100 microM, 200 microM or 400 microM cysteamine. In Experiment 2, oocytes were matured with 400 microM cysteamine and following in vitro fertilization (IVF) were cultured in SOF medium supplemented with 50 microM and 100 microM cysteamine. In Experiment 1, BCB+ oocytes matured with 100 microM and 200 microM cysteamine showed higher normal fertilization and embryo development rates than BCB- oocytes. Oocytes matured with 400 microM cysteamine did not present these differences between BCB+ and BCB- oocytes. In Experiment 2, the addition of 50 microM and 100 microM cysteamine to culture medium did not affect the proportion of total embryos obtained from BCB+ oocytes (35.89% and 38.29%, respectively) but was significantly different in BCB- oocytes (34.23% and 29.04%, respectively, P < 0.05). In conclusion, the addition of 400 microM cysteamine to the IVM improved normal fertilization and embryo development of BCB- oocytes at the same rates as those obtained from BCB+ oocytes. The proportions of morulae plus blastocyst development were not affected by the treatments.     

Early Effects of Penconazole on H+ and K+ Transport,Electrolyte Leakage and Transmembrane Electrical Potential in Egeria densa Leaves

The early effects of penconazole (PCZ) at relatively high concentration (10^?4 to 5 × 10^?4 M) on changes in pH and in titratable acidity of the medium, transmembrane electrical potential difference (Em), electrolyte leakage and cell morphology were investigated in Egeria densa leaves. At the lowest (10^?4 M) concentration and in the presence of a very low (10 μM) K⁺ concentration, triazole induced an early, moderate hyperpolarization of Em, associated with a decrease of net K⁺ uptake, suggesting some increase in the passive permeability to K⁺. This Em hyperpolarization was no longer detectable at high (2 mM) K⁺_out concentration. At high PCZ concentrations (3 × 10^?4 M and 5 × 10^?4 M) the early hyperpolarization detectable in the presence of a low K⁺_out concentration became transient, and was followed by a marked depolarization. PCZ, at these concentrations, suppressed acidification of the medium, stimulated electrolyte leakage and, in the mesophyll cells, induced some shrinking of the cytoplasm and its disconnection from the cell walls. These results are interpreted as due to an early effect of this triazole leading to the disorganization of the plasma membrane.     

Different expression and genetic control for the K99 antigen and its associated adhesin

Cultivation of K99⁺ wild strains and transconjugants in MINCA medium with variable concentrations of glucose, glycerol, alanine, or protein-interfering antibiotics shows that the K99 antigen and its associated adhesin are expressed in different ways. The addition of cAMP to medium containing a K99-repressive concentration of glucose demonstrates that the K99-antigen production is controlled by the cAMP-CRP complex, but this does not occur with the adhesin production. Sub-inhibitory concentrations of protein-interfering antibiotics inhibit the K99-antigen production, but do not correlatively affect the adhesin production. All these experiments suggest that the K99 antigen and the adhesin are different structures whose genes are controlled by different mechanisms.     

Inhibition of protein kinase B (PKB) and PKCzeta mediates keratin K10-induced cell cycle arrest

The intermediate filament cytoskeleton is composed of keratins in all epithelial cells and imparts mechanical integrity to these cells. However, beyond this shared function, the functional significance of the carefully regulated tissue- and differentiation-specific expression of the large keratin family of cytoskeletal proteins remains unclear. We recently demonstrated that expression of keratin K10 or K16 may regulate the phosphorylation of the retinoblastoma protein (pRb), inhibiting (K10) or stimulating (K16) cell proliferation (J. M. Paramio, M. L. Casanova, C. Segrelles, S. Mittnacht, E. B. Lane, and J. L. Jorcano, Mol. Cell. Biol. 19:3086-3094, 1999). Here we show that keratin K10 function as a negative modulator of cell cycle progression involves changes in the phosphoinositide 3-kinase (PI-3K) signal transduction pathway. Physical interaction of K10 with Akt (protein kinase B [PKB]) and atypical PKCzeta causes sequestration of these kinases within the cytoskeleton and inhibits their intracellular translocation. As a consequence, the expression of K10 impairs the activation of PKB and PKCzeta. We also demonstrate that this inhibition impedes pRb phosphorylation and reduces the expression of cyclins D1 and E. Functional and biochemical data also demonstrate that the interaction between K10 and these kinases involves the non-alpha-helical amino domain of K10 (NTerm). Together, these results suggest new and essential roles for the keratins as modulators of specific signal transduction pathways.     

Superinfection in Bacteriophage S13 and Determination of the Number of Bacteriophage Particles Which Can Function in an Infected Cell

Bacteriophage S13 shows exclusion of superinfecting homologous phage, but the exclusion is only partial. The superinfecting phage can form infectious replicative form deoxyribonucleic acid (RF), can direct protein synthesis, and can form progeny particles even at a superinfection time as late as 60 min after the first infection. Exclusion is also only partial for the closely related phage phiX174. Seven min after the first infection, the exclusion mechanism begins to operate, requiring continuous phage-specified protein synthesis. The gene A protein (required for synthesis of progeny RF) appears to be involved in the exclusion mechanism. In superinfection experiments, it was found that at least 40 phage particles per cell can replicate and can carry out protein synthesis, though the number of sites for binding of RF to the membrane is only about 15 per cell. The results suggest that attachment of RF to a binding site is not required for protein synthesis. Evidence is presented that non-attached parental RF can serve as a template for single-stranded deoxyribonucleic acid synthesis.