Lipid Droplet Analysis Using In Vitro Bovine Oocytes and Embryos

The aim of this study was to quantify the content of lipid droplets in bovine oocytes and embryos from Bos indicus (Bi), Bos taurus (Bt) and Bos indicus × Bos taurus (Bi × Bt). Oocytes were aspirated post‐mortem and subjected to in vitro maturation, in vitro fertilization and in vitro development; the medium employed at each stage (TCM‐199, TALP, SOF) was supplemented with (i) serum replacement (SR), (ii) foetal calf serum (FCS) or (iii) oestrous cow serum (ECS). The structure and distribution of the lipid droplets were established using electron microscopy, but were quantified using an optical microscope on semi‐fine toluidine blue‐stained sections. The highest percentage of embryos corresponded to those produced with FCS and ECS, which differed from embryos generated with SR (p < 0.05). The highest percentage of morulae and the lowest percentage of blastocysts were obtained with the SR supplement (p < 0.05). The oocytes cultured in FCS demonstrated a higher number of lipid droplets compared to those cultured in SR and ECS (p < 0.05). Less accumulation of lipids was observed in embryos supplemented with SR. The lowest and highest numbers of lipid droplets in oocytes corresponded to the Bi and Bt strain, respectively. The lowest amount of lipid droplets in embryos was observed in Bi (p < 0.05). In conclusion, supplementation of the in vitro development culture medium (synthetic oviduct fluid) with a synthetic substitute serum produced similar results in terms of embryo development compared to those obtained with FCS, but a decreased degree of lipid droplet accumulation was observed in the in vitro‐cultured embryos.     

Reproductive biology of pink dentex Dentex gibbosus (Rafinesque) from the Adriatic Sea, Croatia

A 4‐year study (May 1997–December 2000) of the reproductive biology of pink dentex Dentex gibbosus (Rafinesque) from the Adriatic Sea revealed that this species is a rudimentary hermaphrodite. The smallest mature males and females captured were 38.70 cm in total length (T_L) and 39.80 cm in total length (T_L) respectively. The von Bertalanffy growth parameters estimated for the entire population were: L_∞=107.24, K=0.12 and t₀=−0.90. Fifty per cent of the population were sexually mature at 41.50 cm T_L, while 100% of the specimens were sexually mature at 57.00 cm T_L. Both monthly gonadosomatic index and macroscopically determined gonad stages strongly indicate that the pink dentex from the Adriatic Sea spawn partially in August, September and October. The mean value of absolute fecundity (F) was 1672 × 10⁶ eggs. The results of great fertility of the pink dentex, partial spawning and relatively late sexual maturation suggest that the pink dentex has a high potential for commercial culture.     

Heterologous strain immunity in bovine babesiosis using a culture-derived soluble Babesia bovis immunogen

The cross-protective capacity of culture-derived soluble immunogens against heterologous Babesia bovis strains from different geographical locations of Latin America was examined. Susceptible yearling cattle were either immunized with immunogens derived from Venezuelan or Mexican strains, or were administered a multi-component immunogen containing antigens of the Australian, Mexican and Venezuelan strains. Cattle were challenged with virulent B. bovis organisms of the Argentinian, Colombian, Ecuadorean, Mexican and Venezuelan strains. The major parameters used to evaluate cross-protection were the following: presence, level and duration of parasitemia; maximal PCV reduction; level and duration of fever; determination of fibrinogen and cryofibrinogen; homologous and heterologous antibody levels; and net gains in body weight. Results showed good protection with a Venezuelan B. bovis immunogen after homologous and heterologous challenge exposures. A low degree of cross-immunity was observed when cattle vaccinated with the Mexican immunogen were challenged with each of the heterologous strains.     

Evaluation and Modification of the OECD 301F Respirometry Biodegradation Test Method with Regard to Test Substance Concentration and Inoculum

The majority of OECD (Organisation for Economic Co-operation and Development) ready biodegradation test methods require a relatively high concentration of test substance. Such high dosage concentrations are unsuitable for screening of inhibitory or biocidal compounds. Unfortunately, the method with the lowest dosage concentration (Closed Bottle Test, 301D) also has the lowest biodegradation potential. Therefore, we have evaluated the ability of the Manometric Respirometry (301F) test method to study biodegradation of test substances at concentrations of a few mgl^?1, using sodium acetate as a model substance. Results have been compared to those obtained from closed bottle tests (301D). Problems with using activated sewage as an inoculum have been demonstrated, as respirometry curves were biphasic, and the recorded biological oxygen demand (BOD) was higher than the calculated theoretical oxygen demand (ThOD). A consortium of bacteria isolated from activated sewage was used as an alternative inoculum. Using the alternative inoculum for respirometry tests, monophasic growth curves were observed with recorded BOD values at expected levels. Sensitivity thresholds for the respirometer tests were comparable to those in closed bottles, with biodegradation being detected at concentrations as low as 2.5 mgl^-1 ThOD. Comparison of whole community carbon source utilisation profiles for both inocula (obtained using BIOLOG microplates) revealed their catabolic potential to be similar. Therefore, use of an activated sewage-derived inoculum is recommended as an alternative inoculum for respirometer-based biodegradation testing.     

Inhibition of cytotoxicity of lymphocytes by concanavalin A in vitro

Human lymphocytes treated with the plant protein concanavalin A are stimulated to transform into blasts, without developing cytotoxicity for chicken erythrocytes. Prior treatment of lymphocytes with concanavalin A potentiated phytohemagglutinin-induced blast transformation and DNA synthesis but completely inhibited phytohemagglutinin-induced cytotoxicity. Inhibiton was not due to suppression of the mixed lymphocyte-erythrocyte aggregation normally caused by phytohemagglutinin. Inhibition of cytotoxicity was reversible when concanavalin A was removed from the lymphocytes by treatment with methyl-alpha-D-manno-pyranoside after 1 hour but not after 20 hours. The results indicate that blast transformation and cytotoxicity are separate expressions of lymphocyte stimulation.     

Deconfined quantum critical points

The theory of second-order phase transitions is one of the foundations of modern statistical mechanics and condensed-matter theory. A central concept is the observable order parameter, whose nonzero average value characterizes one or more phases. At large distances and long times, fluctuations of the order parameter(s) are described by a continuum field theory, and these dominate the physics near such phase transitions. We show that near second-order quantum phase transitions, subtle quantum interference effects can invalidate this paradigm, and we present a theory of quantum critical points in a variety of experimentally relevant two-dimensional antiferromagnets. The critical points separate phases characterized by conventional "confining" order parameters. Nevertheless, the critical theory contains an emergent gauge field and "deconfined" degrees of freedom associated with fractionalization of the order parameters. We propose that this paradigm for quantum criticality may be the key to resolving a number of experimental puzzles in correlated electron systems and offer a new perspective on the properties of complex materials.     

Sequence variants in SLITRK1 are associated with Tourette's syndrome

Tourette's syndrome (TS) is a genetically influenced developmental neuropsychiatric disorder characterized by chronic vocal and motor tics. We studied Slit and Trk-like 1 (SLITRK1) as a candidate gene on chromosome 13q31.1 because of its proximity to a de novo chromosomal inversion in a child with TS. Among 174 unrelated probands, we identified a frameshift mutation and two independent occurrences of the identical variant in the binding site for microRNA hsa-miR-189. These variants were absent from 3600 control chromosomes. SLITRK1 mRNA and hsa-miR-189 showed an overlapping expression pattern in brain regions previously implicated in TS. Wild-type SLITRK1, but not the frameshift mutant, enhanced dendritic growth in primary neuronal cultures. Collectively, these findings support the association of rare SLITRK1 sequence variants with TS.     

Slipping magnetic reconnection in coronal loops

Magnetic reconnection of solar coronal loops is the main process that causes solar flares and possibly coronal heating. In the standard model, magnetic field lines break and reconnect instantaneously at places where the field mapping is discontinuous. However, another mode may operate where the magnetic field mapping is continuous but shows steep gradients: The field lines may slip across each other. Soft x-ray observations of fast bidirectional motions of coronal loops, observed by the Hinode spacecraft, support the existence of this slipping magnetic reconnection regime in the Sun's corona. This basic process should be considered when interpreting reconnection, both on the Sun and in laboratory-based plasma experiments.     

Concanavalin A reaction with human normal immunoglobulin G and myeloma immunoglobulin G

Concanavalin A precipitated less than 5 percent of immunoglobulin G from human serum. It reacted with all of 42 myeloma serums of the immunoglobulin G type tested, but no more than approximately 50 percent of the total myeloma protein was ever precipitated. The fact that not all of the protein was precipitated and that the amounts precipitated varied from serum to serum may be interpreted as demonstrating heterogeneity of the carbohydrate in these myeloma proteins. Other glycoproteins precipitated by concanavalin A were identified, and subsequently separated from concanavalin A by chromatography.