Lipid content and apoptosis of in vitro-produced bovine embryos as determinants of susceptibility to vitrification

The objective was to evaluate supplementation of fetal calf serum (FCS) and phenazine ethosulfate (PES), a metabolic regulator that inhibits fatty acid synthesis, in culture media during in vitro production (IVP) of bovine embryos. Taking oocyte fertilization (n = 4,320) as Day 0, four concentrations of FCS (0, 2.5, 5, and 10%) and three periods of exposure to PES (without addition—Control; after 60 h—PES Day 2.5 of embryo culture; and after 96 h—PES Day 4) were evaluated. Increasing FCS concentration in the culture media enhanced lipid accumulation (P < 0.05), increased apoptosis in fresh (2.5%: 19.1 ± 1.8 vs 10%: 28.4 ± 2.3, P < 0.05; mean ± SEM) and vitrified (2.5%: 42.8 ± 2.7 vs 10%: 69.2 ± 3.4, P < 0.05) blastocysts, and reduced blastocoele re-expansion after vitrification (2.5%: 81.6 ± 2.5 vs 10%: 67.3 ± 3.5, P < 0.05). The addition of PES in culture media, either from Days 2.5 or 4, reduced lipid accumulation (P < 0.05) and increased blastocoele re-expansion after vitrification (Control: 72.0 ± 3.0 vs PES Day 2.5: 79.9 ± 2.8 or PES Day 4: 86.2 ± 2.4, P < 0.05). However, just the use of PES from D4 reduced apoptosis in vitrified blastocysts (Control: 52.0 ± 3.0 vs PES Day 4: 39.2 ± 2.4, P < 0.05). Independent of FCS withdrawal or PES addition to culture media, the in vivo control group had lesser lipid accumulation, a lower apoptosis rate, and greater cryotolerance (P < 0.05). The increased lipid content was moderately correlated with apoptosis in vitrified blastocysts (r = 0.64, P = 0.01). In contrast, the increased apoptosis in fresh blastocysts was strongly correlated with apoptosis in vitrified blastocysts (r = 0.94, P < 0.0001). Therefore, using only 2.5% FCS and the addition of PES from Day 4, increased the survival of IVP embryos after vitrification. Moreover, embryo quality, represented by the fresh apoptosis rate, was better than lipid content for predicting embryo survival after vitrification.     

Epipelagic siphonophore assemblages associated with water masses along a transect between Chile and Easter Island (eastern South Pacific Ocean)

We analyze for the first time the spatial distribution of siphonophoresin relation to water masses along a 3750-km oceanic transectbetween the Chilean coast and the Easter Island (27° S),a sector scarcely known of eastern South Pacific Ocean. Thirty-onesiphonophore species were identified; Sulculeolaria turgidaand Vogtia glabra were recorded for the first time in this sector.The most abundant species were Muggiaea atlantica (29.2%), Eudoxoidesspiralis (24.5%) and Lensia subtilis (13.1%). Two differentsiphonophore assemblages east and west of 76 W, associated respectivelywith Subantarctic Water and Subtropical Water masses, can beused as water mass indicators. The former included the threemost abundant species, whereas the latter showed greater speciesrichness. This study provides basic knowledge on spatial distributionof siphonophores, which is important to develop future researchfocused on understanding the ecological role and biologicalprocesses driven by planktonic organisms in the southeasternPacific Ocean.     

New circuits for old memories: the role of the neocortex in consolidation

Studies of learning and memory have provided a great deal of evidence implicating hippocampal mechanisms in the initial storage of facts and events. However, until recently, there were few hints as to how and where this information was permanently stored. A recent series of rodent molecular and cellular cognition studies provide compelling evidence for the involvement of specific neocortical regions in the storage of information initially processed in the hippocampus. Areas of the prefrontal cortex, including the anterior cingulate and prelimbic cortices, and the temporal cortex show robust increases in activity specifically following remote memory retrieval. Importantly, damage to or inactivation of these areas produces selective remote memory deficits. Additionally, transgenic studies provide glimpses into the molecular and cellular mechanisms underlying cortical memory consolidation. The studies reviewed here represent the first exciting steps toward the understanding of the molecular, cellular, and systems mechanisms of how the brain stores our oldest and perhaps most defining memories.     

Effect of corticotropin-releasing factor on adrenal DBH and PNMT activity

The continuous administration of CRF (corticotropin-releasing factor) by the intraventricular route, 100 ng/day, to rats over a period of 7 days, results in significant increases of DBH (dopamine beta-hydroxylase) and PNMT (phenethanol N-methyltransferase) activities in the adrenal glands. The pattern of increase in DBH response to various doses of CRF does not correspond to the effects observed on plasma corticosterone, a result that suggests that CRF is acting to increase the adrenal enzyme by means other than through the pituitary-adrenal axis. In contrast, PNMT responds to CRF in a manner indicating a correlation with glucocorticoid availability. Moreover, PNMT induction by CRF persists even after adrenal denervation; it also occurs when CRF is given subcutaneously for 3 days, in a dose of 60 ng/day. Injection of reserpine did not potentiate the effect of intraventricularly administered CRF.     

Passive restoration in Araucaria Forest: useful ecological indicators in monitoring successional advancement in exotic tree plantation landscapes

Monitoring successional advancement is a complex field involving a constant search for applied ecological indicators which facilitate monitoring of secondary forests for both active and passive restoration. In this study, the authors investigate the successional advancement of floristics and tree structure within Araucaria Forest (AF) fragments under passive restoration in a context where exotic tree plantations (mainly Pinus L. genus) dominate the landscape. The ecological indicators used were floristic dissimilarity (β‐diversity inferences), indicator species, ecological groups of species, basal area, and species abundance distribution (SAD) models (α‐diversity inferences). A total of 182 tree species belonging to 91 genera and 43 botanical families were identified. A high β diversity was verified for which each site has indicator species (for the locations CD—Dicksonia sellowiana; CO—Cryptocarya aschersoniana; and PG—Pinus taeda), where pioneer species contributed to much of the abundance. Different SAD models are useful for describing passive restoration sites in exotic tree plantation landscapes, namely Lognormal, Mandelbrot, and Zipf. SAD models together with basal area, taxonomic group (e.g. Myrtaceae assemblage), and tree abundance in ecological groups are strategic ecological indicators for monitoring successional advancement in AF.     

A reusable amperometric biosensor based on a novel silver-epoxy electrode for immunoglobulin detection

A renewable immunosensor consisting of an `epoxygraphite' biocomposite containing silver and tetracyanoquinodimethane (TCNQ) is described. These compounds enhance conductivity allowing the use of a smaller potential (0.28 v) which, in turn, enhances selectivity. This sensor, which may be renewed by simple polishing of its surface, was employed to detect human IgG using peroxidase-coupled anti-human IgG.     

Callus,shoot and hairy root formation in vitro as affected by the sensitivity to auxin and ethylene in tomato mutants

We analyzed the impact of ethylene and auxin disturbances on callus, shoots and Agrobacterium rhizogenes-induced hairy root formation in tomato (Solanum lycopersicum L.). The auxin low-sensitivity dgt mutation showed little hairy root initiation, whereas the ethylene low-sensitivity Nr mutation did not differ from the control Micro-Tom cultivar. Micro-Tom and dgt hairy roots containing auxin sensitivity/biosynthesis rol and aux genes formed prominent callus onto media supplemented with cytokinin. Under the same conditions, Nr hairy roots did not form callus. Double mutants combining Rg1, a mutation conferring elevated shoot formation capacity, with either dgt or Nr produced explants that formed shoots with little callus proliferation. The presence of rol + aux genes in Rg1 hairy roots prevented shoot formation. Taken together, the results suggest that although ethylene does not affect hairy root induction, as auxin does, it may be necessary for auxin-induced callus formation in tomato. Moreover, excess auxin prevents shoot formation in Rg1.