Climate-forced variability of ocean hypoxia

Oxygen (O(2)) is a critical constraint on marine ecosystems. As oceanic O(2) falls to hypoxic concentrations, habitability for aerobic organisms decreases rapidly. We show that the spatial extent of hypoxia is highly sensitive to small changes in the ocean's O(2) content, with maximum responses at suboxic concentrations where anaerobic metabolisms predominate. In model-based reconstructions of historical oxygen changes, the world's largest suboxic zone, in the Pacific Ocean, varies in size by a factor of 2. This is attributable to climate-driven changes in the depth of the tropical and subtropical thermocline that have multiplicative effects on respiration rates in low-O(2) water. The same mechanism yields even larger fluctuations in the rate of nitrogen removal by denitrification, creating a link between decadal climate oscillations and the nutrient limitation of marine photosynthesis.     

Effect of the well of the well (WOW) system on in vitro culture for porcine embryos after intracytoplasmic sperm injection

For developmental competence of porcine embryos in vitro, it is important to improve the culture environment. The present study was performed to evaluate four different culture systems for in vitro matured porcine oocytes following intracytoplasmic sperm injection (ICSI); drop, well and two sizes of the well of the well (WOW) systems (500 and 1,000 microm in diameter). The cleavage rate on Day 2 and the mean cell number in blastocysts on Day 6 were not significantly different among the four treatments. However, the 1,000 microm WOW (24.6%) resulted in a significantly higher (P<0.05) blastocyst rate than those in the other culture systems (12.9, 14.8, and 7.1% for drop, well, and 500 microm WOW, respectively). The present study indicates that the microenvironment created by the 1,000 microm diameter WOW improves blastocyst production of in vitro matured porcine oocytes after ICSI, and that the effectiveness of the WOW system is dependent on the size (diameter) of the WOW.     

Plasmid profiles of virulent Rhodococcus equi isolates from soil environment on horse-breeding farms in Hungary

The plasmid profiles of virulent Rhodococcus equi strains isolated on three horse-breeding farms located in different parts of Hungary were investigated. From 49 soil samples collected on the three farms, 490 R. equi isolates (10 from each sample) were obtained and tested for the presence of 15- to 17-kDa antigens (VapA) by immunoblotting and PCR. Ninety-eight VapA-positive isolates were detected from 30 of the 49 culture-positive samples with a prevalence ranging from 13.1% to 23.2%. Of the 98 virulent isolates, 70 contained an 85-kb type I plasmid, 13 contained an 87-kb type I plasmid, and 15 contained an 85-kb type III plasmid which had been uniquely isolated from soil isolates in the United States. This study demonstrates that the virulent form of R. equi is very widespread in the soil environment of these stud farms in Hungary and the plasmid pattern is different from farm to farm.     

Effects of trichostatin A on in vitro development and transgene function in somatic cell nuclear transfer embryos derived from transgenic Clawn miniature pig cells

The present study was carried out to examine the effects of post‐activation treatment of trichostatin A (TSA), a histone deacetylase inhibitor, on in vitro development and transgene function of somatic cell nuclear transfer (SCNT) embryos derived from Clawn miniature pig embryonic fibroblast (PEF) transfected with a bacterial endo‐β‐galactosidase C gene (removal of the α‐galactosyl (Gal) epitope). SCNT embryos were incubated with or without TSA (50 or 100 nmol/L) after activation, cultured in vitro and assessed for cleavage, blastocyst formation and transgene function. The rate of blastocyst formation was significantly higher in SCNT embryos treated with 50 nmol/L TSA than that in control (P < 0.05), whereas the rate of cleavage and cell number of blastocyst did not differ. Following labelling with fluorescein isothiocyanate‐labelled BS‐I‐B₄ isolectin, the intensity of fluorescence observed on cell‐surface was dramatically reduced in transgenic SCNT blastocyst in comparison with non‐transgenic SCNT blastocyst. However, the reduction of α‐Gal epitope expression in transgenic SCNT blastocyst was not affected by TSA treatment. The results of this study showed that post‐activation treatment with 50 nmol/L TSA is effective to improve in vitro developmental capacity of transgenic SCNT miniature pig embryos without the modification of transgene function.     

Antibody reactivity in mice and cats to feline enteroepithelial stages of Toxoplasma gondii.

The reactivity of antibodies in mice and cats to feline enteroepithelial stages of Toxoplasma gondii was examined by means of an indirect immunofluorescent antibody test. Mice immunized with feline enteroepithelial stage (FES) parasites produced antibodies not only against FES, but also against tachyzoites, sporozoites/oocysts, tissue cysts and one part of the infected feline enterocytes. After absorption with tachyzoites, the titer of antibodies reactive to enterocytes was significantly reduced. In contrast, the titer of antibodies reactive to FES remained unchanged. The antibodies from cats immunized with FES, reacted specifically to FES, but not to tachyzoites, tissue cysts or enterocytes. These results suggest that FES parasites may have stage-specific antigen(s).     

Infectivity of feline enteroepithelial stages of Toxoplasma gondii isolated by Percoll-density gradient centrifugation.

The infectivity of the feline enteroepithelial stages of Toxoplasma gondii isolated by Percoll-density gradient centrifugation was examined by the trypan blue dye exclusion method by assaying their penetration into feline fibroblast cells in vitro and by inoculation of the intestinal mucosa of cats. A large population of the parasites showed trypan blue dye exclusion activity. When feline fibroblast cells were inoculated with feline enteroepithelial stage parasites, no intracellular parasites were found 18 h post-inoculation. Kittens inoculated intraduodenally with 2 x 10(6) feline enteroepithelial stage parasites shed oocysts between 2 and 8 days post-inoculation. These results indicate that the isolated feline enteroepithelial stage parasites display infectivity towards enterocytes of cats and are capable of gametogenesis.     

LTSER platforms as a place-based transdisciplinary research infrastructure: learning landscape approach through evaluation

Landscape Ecology - Place-based transdisciplinary research involves multiple academic disciplines and non-academic actors. Long-Term Socio-Ecological Research (LTSER) platform is one concept with ~...