Search results for "Tetrad"

High-performance liquid chromatographic study of the regulation of phospholipid metabolism in cultured adrenocortical cells

1994

Abstract A rapid high-performance liquid chromatographic (HPLC) method for the separation of phospholipids was developed for minute samples of total lipids (ca. 200 μg). The method was applied to the study of the phospholipid metabolism in adrenocortical cell cultures. A complete separation of the different cellular phospholipid classes was achieved in 40 min. Good resolution of the phospholipid peaks was obtained, which allowed the collection of each individual class of phospholipids for further analysis of radioactivity and fatty acid composition by gas chromatography. When cells were incubated with [U-14C]glycerol or [U-14C]palmitate the bulk of the radioactivity was found in cellular ph…

A role for the immunoglobulin-like domain of the human IL-6 receptor. Intracellular protein transport and shedding.

1999

Interleukin (IL)-6, IL-11 and cililary neurotrophic factor (CNTF) belong to the same family of hematopoietic and neurotrophic cytokines. Their receptor complexes contain a cytokine-binding alpha receptor and the common glycoprotein (gp)130 subunit for signal transduction. The extracellular parts of the alpha-receptor subunits consist of a membrane-proximal cytokine-binding domain and an N-terminal immunoglobulin (Ig)-like domain with unknown function. We examined the role of the Ig-like domain of IL-6R by constructing deletion mutants lacking the Ig domain (IL-6RDeltaIg and soluble IL-6RDeltaIg). IL-6RDeltaIg was shed as effectively as wild-type IL-6R from transfected COS-7 cells upon 4beta…

Effects of tetradifon on Daphnia magna during chronic exposure and alterations in the toxicity to generations pre-exposed to the pesticide.

2000

Daphnia magna was exposed to some nominal sublethal tetradifon concentrations (0.10, 0.18, 0.22 and 0.44 mg/l) during 21 days. Chronic toxicity tests were carried out using neonates of F(1) first brood (F(1)-1st) and F(1) third brood (F(1)-3rd) offspring generations from parentals (F(0)) pre-exposed to the pesticide. The effect of tetradifon on survival, reproduction and growth was monitored for the selected daphnid generations. The parameters used to evaluate pesticide effect on reproduction were: mean total young per female, mean brood size, time to first reproduction, mean number broods per female and intrinsic rate of natural increase (r). Survival and growth (body length) were also det…

On selfdual spin-connections and asymptotic safety

2016

We explore Euclidean quantum gravity using the tetrad field together with a selfdual or anti-selfdual spin-connection as the basic field variables. Setting up a functional renormalization group (RG) equation of a new type which is particularly suitable for the corresponding theory space we determine the non-perturbative RG flow within a two-parameter truncation suggested by the Holst action. We find that the (anti-)selfdual theory is likely to be asymptotically safe. The existing evidence for its non-perturbative renormalizability is comparable to that of Einstein-Cartan gravity without the selfduality condition.

Diacylglycerols containing Omega 3 and Omega 6 fatty acids bind to RasGRP and modulate MAP kinase activation.

2003

We elucidated the effects of different diacylglycerols (DAGs), i.e. 1-stearoyl-2-arachidonoyl-sn-glycerol (SAG), 1-stearoyl-2-docosahexaenoyl-sn-glycerol (SDG), and 1-stearoyl-2-eicosapentaenoyl-sn-glycerol (SEG), on [3H]PDBu binding to RasGRP. The competition studies with these DAGs on [3H]PDBu binding to RasGRP revealed different Ki values for these DAG molecular species. Furthermore, we transfected human Jurkat T cells by a plasmid containing RasGRP and assessed the implication of endogenous DAGs on activation of MAP kinases ERK1/ERK2, induced by phorbol-12-myristate-13-acetate (PMA). In control cells, GF109203X, a protein kinase C inhibitor, inhibited ERK1/ERK2 activation. However, this…

Gas chromatographic determination of organochlorine pesticides; contamination of dicofol, fenson, and tetradifon in fish and natural waters of a wet …

1986

Accumulation of Tetradifon in an Algae ( Nannochloris oculata ) and the Cladoceran, Daphnia magna

1996

Dissipation and distribution of atrazine, simazine, chlorpyrifos, and tetradifon residues in citrus orchard soil.

1997

An environmental fate study was conducted in a citrus orchard plot in Valencia (Spain) in the fall of 1993. Dissipation and distribution of atrazine, simazine, chlorpyrifos and tetradifon residues following their controlled addition for agricultural purposes in a mediterranean red soil (Luvic Calcisol, Rhodoxeralf) were evaluated. During a two-month period, the amounts of applied pesticides in different soil layers (0-0.05, 0.05-0.22, 0.22-0.42, and 0.42-0.52 m) were monitored. In addition, information on soils, weather and agricultural practice were collected. Degradation half-lives were calculated, assuming zero-order kinetics: 11 days for atrazine, 12 days for simazine, 10 days for chlor…

Daphnia magna feeding behavior after exposure to tetradifon and recovery from intoxication.

1999

Abstract The feeding behavior of the cladocera Daphnia magna subjected to a short-term exposure to the acaricide tetradifon (4-chlorophenyl 2,4,5-trichlorophenyl sulfone) was studied. The experiments were performed using the unicellular algae Nannochloris oculata at a density of 5×10 5 cells/ml as food for the organisms. In a first experiment, three generations (F0, F1, and F3) of the daphnids were exposed to sublethal levels of tetradifon (0.1, 0.18, 0.22, and 0.44 mg/l) and the effect of the toxicant on filtration and ingestion rates was determined. Rates of filtration and ingestion of D. magna declined in the three generations studied with increasing toxicant concentrations; however, tox…

Population dynamics in Daphnia magna as modified by chronic tetradifon stress.

2000

Two Daphnia magna offsprings (animals from the first and third brood) whose parentals (F0-generation) were exposed during 21 days to different tetradifon (4-chlorophenyl 2,4,5-trichlophenyl sulfone) concentrations, were transferred to a pesticide free medium during 21 days (recovery period). The algae Nannochloris oculata (5 x 10(5) cells/mL) was used as food. In this recovery study, survival, growth and reproduction (mean total young per female, mean brood size, onset of reproduction and mean number broods per female) were assessed as individual parameters and the intrinsic rate of natural increase (r) as population parameter, for F1 generation (1st and 3rd broods). Reproduction was still …