A redox system for brain targeted estrogen delivery causes chronic body weight decrease in rats

The effects of 2 redox based carriers for brain directed delivery of estradiol (CDS-E2) and ethinyl estradiol (CDS-EE) on body weight were examined in rats. A single dose of CDS-E2 (3 mg/kg) decreased weight gain in castrate rats for at least 24 days. The dose response of weight gain and LH suppression were compared 12 days and 12 to 25 after CDS-E2 and CDS-EE, respectively, in ovariectomized (OVX) rats. Weight decrease was detected at a lower dose and was significant for longer after drug treatment than LH decrease. Both compounds were more potent than equimolar estradiol or estradiol valerate in reducing weight gain. Intact rats also showed decreased weight gain but were less sensitive to CDS-E2 compared to OVX rats. The effects appeared to be estrogen specific as carrier-linked testosterone had no effect on weight. The mechanisms of sustained and potent drug effects on weight are being explored.     

Habitat characteristics contributing to local occupancy and habitat use in rock pool <Emphasis Type="Italic">Daphnia</Emphasis> metapopulations

The effects of invasive macrophytes, water level fluctuations and predation on freshwater unionids Pyganodon grandis and Utterbackia imbecillis were studied in three small impoundments in Northeastern Texas in 2003–2005. Mussel density was sampled with quadrats. Mortality, associated with the water level fluctuations and predation, was estimated by collecting dead shells on the shore at about two month intervals. In two ponds, horizontal distribution of unionids was limited by dense beds of invasive and noxious macrophytes (mainly Eurasian watermilfoil Myriophyllum spicatum and American lotus Nelumbo lutea): mussel densities were significantly lower in these macrophyte beds (P < 0.001). In the third pond with the lowest density of macrophytes (stonewort Chara sp.), unionids were distributed more evenly, and the average unionid biomass was the highest among all ponds studied. Vertical distribution of unionids in all ponds was likely limited by low oxygen at depth >2 m. The total amount of shells found on the shore per year varied from 0.1% to 28% of the total population in the pond and was negatively correlated with water level (r = −0.72 to −0.81, P < 0.005). Mammalian predators consumed up to 19% of the total unionid population and predation was facilitated by water level fluctuations. Handling editor: K. Martens     

Esters of trehalose from Corynebacterium diphtheriae: A modified purification procedure and studies on the structure of their constituent hydroxylated fatty acids

The purification procedure of 6,6′-diesters of trehalose from Corynebacterium diphtheriae was modified and the isolated substance was analysed by mass spectrometry as its permethylated derivative. The fatty acid moiety released from the glycolipid after alkaline hydrolysis was studied by mass spectral analysis of the O-methylated and O-acetylated methyl ester derivatives. By argentation thin-layer chromatography, three species of O-acetylated methyl esters were recognized, corresponding to saturated, mono-unsaturated and di-unsaturated α-branched-β-hydroxylated fatty acids. The double bond was located by ozonolysis of the O-acetylated methyl ester derivatives, by gas chromatography of the reaction product and mass spectrometry of the effluent from the gas chromatograph. The main components of each species of α-branched-β-hydroxylated fatty acids found in the gly colipid fraction of C. diphtheriae were 2-tetradecyl-3-hydroxyoctadecanoic acid (C₃₂H₆₄O₃, corynomycolic acid), 2-tetradecyl-3-hydroxy-11-octadecenoic acid (C₃₂H₆₂O₃, corynomycolenic acid), 2-tetradec-7′-enyl-3-hydroxy octadecanoic acid (C₃₂H₆₂O₃) and 2-tetradec-7′-enyl-3-hydroxy-11-octadecenoic acid (C₃₂H₆₀O₃, corynomycoldienic acid). The glycolipid fraction from C. diphtheriae is obviously a complex mixture of 6,6′-diesters of trehalose.     

Stimulation of uridine phosphorylation in primary cultures of Xenopus laevis hepatocytes by estradiol-17 beta

The effects of estrogen on the uridine uptake into cells were examined in primary cultures of liver parenchymal cells from Xenopus laevis. The total uptake of [3H]uridine into the estrogen-treated cells and its incorporation into RNA were about 1.5 times higher than the values for control cells. The uptake of [3H]adenosine and its incorporation into RNA were not affected by estrogen. An experiment in which liver parenchymal cells were double labeled with [3H]uridine and [3H]adenosine showed that estrogen elevated the specific radioactivity of the UTP pool 1.4-fold the value found for the control cells, but that of the ATP pool was not altered by estrogen. Short term labeling revealed that estrogen did not significantly alter the rate of the initial uptake of [3H]uridine into the cells, but it did stimulate [3H]uridine phosphorylation about 1.7-fold. Uridine kinase activity measured in cell-free extracts of hepatocytes treated with estrogen had a value 1.6 times that of the control cells. These data indicate that the stimulation of [3H]uridine uptake and phosphorylation in Xenopus laevis hepatocytes in the presence of estrogen is caused by the enhancement of uridine kinase activity.     

Site-directed mutagenesis in the uracil-repair system. Preparation of mutated forms of human alpha 2 interferon

The mutant forms of human IFN-alpha 2 gene are obtained by oligonucleotide-directed mutagenesis with the use of uracil-repair system. To intensify the process the procedure of the uracil-containing DNA template preparation is modified. It was determined that when mutagenesis is performed in the uracil-repair system the yield of the process depends on the mutant DNA-strand in vitro synthesis efficiency. It is shown that the stability of the 5'-end primer-template complex and the level of the endogenic primers elongation are the basis factors, that determine induction mutations.