Iris stromal pigment cells of the ringed turtle dove

Irides from adult Ringed Turtle Doves (Streptopelia risoria) were examined using both light and electron microscopy. The anterior surface of the iris stroma contained numerous large venous sinuses overlying bright yellow pigment cells which we classified as "reflecting xanthophores." The pigment cells were filled with irregularly arranged yellow reflecting crystals and occasional pterinosome-like structures. The irides were extracted in NaOH and the extracted pigments analyzed using paper chromatography and spectrophotometry. A unique bright orange fluorescent band was found in the iris extract, but the chemical nature of the band was not determined. Although guanine was expected to be a major component of the reflecting "platelets," based on previous work with other Columbiformes, it could not be demonstrated chromatographically or spectrophotometrically.     

Regulation of hexose transporters in chicken embryo fibroblasts: stimulation by the phorbol ester TPA leads to increased numbers of functioning transporters

As has been observed with many types of cultured cells, chicken embryo fibroblasts (CEF) when exposed to the tumor promoter 12-O-tetradecanoyl-phorbol-13-acetate (TPA) develop a 3- to 4-fold increase in hexose transport activity in 4 h. This increase in transport activity occurred despite a modest decline of 20% in [3H]leucine incorporation into acid insoluble fractions. Cycloheximide largely, but not completely, blocked the increase in transport activity during TPA exposure. The effects of TPA were somewhat similar to those of glucose starvation induced enhancement of hexose transport activity. Furthermore, with TPA there was no additive effect to that produced by glucose starvation. Plasma membrane enriched fractions were prepared from CEF treated with or without TPA. Membranes prepared from TPA exposed cells had a two-fold enhancement of stereospecific D-glucose transport activity as well as D-glucose inhibitable [3H]cytochalasin B binding as compared to the membranes from control CEF. There was no effect on transport when membranes were exposed to TPA in vitro. These results provide strong evidence that TPA exposure leads to an increase in the number of functioning transporters, an effect largely requiring protein synthesis.     

Cephalexin and Cephaloglycin Activity In Vitro and Absorption and Urinary Excretion of Single Oral Doses in Normal Young Adults

A large number of recently isolated bacterial pathogens were tested for susceptibility to cephalexin and cephaloglycin by the replica inoculating method. Strains of group A hemolytic streptococci, viridans (alpha and gamma) streptococci, pneumococci, gonococci, meningococci, and penicillin G-sensitive Staphylococcus aureus were all moderately to highly susceptible to both of these cephalosporin analogues, nearly all of the strains being two to eight (median four) times more susceptible to cephaloglycin than to cephalexin. The penicillin G-resistant, penicillinase-producing strains of S. aureus varied in their susceptibility; many were moderately resistant to both analogues, particularly to cephalexin. Strains of enterococci, Haemophilus influenzae, and most of the common gram-negative bacilli were moderately to highly resistant. Reducing the size of the inoculum had variable effects on inhibition by these drugs, depending on the species or strain. The activity of cephalexin was very little affected by pH of the medium within the clinical range or by incubation at 37 C in broth for up to 24 hr. In contrast, cephaloglycin in broth deteriorated rapidly at 37 C, and its activity was markedly reduced in alkaline medium. Both cephalexin and cephaloglycin were rapidly absorbed and excreted into the urine after single oral doses of 500 mg. Much higher levels were achieved and sustained with the former. Absorption of both analogues was delayed when taken with food, and the levels in the serum were significantly higher and better sustained when probenecid was also given. Very high concentrations of cephalexin were excreted into the urine during the first 4 hr, and the levels were still high in the 4- to 8-hr collection. The concentrations of cephaloglycin in the urine at these times were much lower. An average of 80 to 93% of the dose of cephalexin and 25 to 30% of the cephaloglycin were accounted for as active drug in the urine collected in 8 hr. Both analogues were well tolerated.     

“Cryptic” dinucleotide polymorphism in the 3′ region of the factor IX gene shows substantial variation among different populations

Long tandem dinucleotide repeats composed of alternating purines and pyrimidines [RY(i)] are abundant and highly polymorphic. Simple RY(i) are predominately composed of one tandem repeat of a dinucleotide sequence. In contrast, cryptic RY(i [cRY(i)] are composed of multiple short dinucleotide repeats. Herein, we describe the racial distribution of alleles for a polymorphic cRY(i) in the factor IX gene. Allele I is absent in Asians, whereas allele III is rare or absent in Caucasians or blacks. A polymorphic cRY(i) analyzed previously shows even more dramatic variation among racial groups, hinting that a battery of cRY(i) might have utility in assessing the racial origin of a DNA sample.     

Axenic isolation of viable Giardia muris trophozoites

Large numbers of viable Giardia muris trophozoites were isolated from the duodenum of experimentally infected mice 6 days after inoculation with 1,000 G. muris cysts. A series of shaking, incubation, and washing steps in the presence of the broad-spectrum antibiotic piperacillin readily provided 4.9 +/- 1.5 x 10(5) G. muris trophozoites per mouse, free of detectable contaminant organisms. Anaerobic and microaerophilic culturing and scanning electron microscopy demonstrated axenic status and high purity of the isolates. The viability of trophozoites was 98 +/- 2%. Application of this technique should permit novel immunological and epidemiological analyses of G. muris infection and biochemical investigations of this protozoan parasite.     

Epidermal growth factor receptor dimerization monitored in live cells

We present a method for monitoring receptor dimerization at the membrane of live cells. Chimeric proteins containing the epidermal growth factor (EGF) receptor extracellular and transmembrane domains fused to weakly complementing beta-galactosidase (beta-gal) deletion mutants were expressed in cells in culture. Treatment of the cells with EGF-like compounds for as little as 15 s resulted in chimeric receptor dimerization detectable as beta-gal enzymatic activity. The dose response of chimeric receptors was ligand specific. beta-galactosidase complementation was reversible upon removal of ligand and could be reinduced. Antibodies that block ligand binding inhibited receptor dimerization and beta-gal complementation. These results demonstrate that beta-gal complementation provides a rapid, simple, and sensitive assay for protein interactions and for detecting and monitoring the kinetics of receptor dimerization.     

Neuronal non-CG methylation is an essential target for MeCP2 function

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ATP-competitive,marine derived natural products that target the DEAD box helicase,eIF4A

Activation of translation initiation is a common trait of cancer cells. Formation of the heterotrimeric eukaryotic initiation factor F (eIF4F) complex is the rate-limiting step in 5′ m7GpppN cap-dependent translation. This trimeric complex includes the eIF4E cap binding protein, the eIF4G scaffolding protein, and the DEAD box RNA helicase eIF4A. eIF4A is an ATP-dependent helicase and because it is the only enzyme in the eIF4F complex, it has been shown to be a potential therapeutic target for a variety of malignancies. To this end, we have used a simple ATPase biochemical screen to survey several hundred marine and terrestrial derived natural products. Herein, we report the discovery of two natural products from marine sources, elisabatin A (1) and allolaurinterol (2), which show low µM inhibition of eIF4A ATPase activity. Enzymological analyses revealed 1 and 2 to be ATP-competitive, and cellular evaluations showed reasonable cytotoxicity against A549 (lung cancer) and MDA-MA-468 (breast cancer) cell lines. However, only compound 2 showed potent inhibition of helicase activity congruent with its ATPase inhibitory activity.     

Water Footprint Symposium: where next for water footprint and water assessment methodology?

Recognizing the need for a comprehensive review of the tools and metrics for the quantification and assessment of water footprints, and allowing for the opportunity for open discussion on the challenges and future of water footprinting methodology, an international symposium on water footprint was organized. The Water Footprint Symposium was held in December 2013 at the University of Leeds, UK. In particular, four areas were highlighted for discussion: water footprint and agriculture, quantification of water footprint, industrial water footprint, and from theory to practice. Discussion was organized to focus on the “prioritization of water footprint research & applications to practical sectors”. The concept of water footprinting has helped to better communicate water management and assessment among different research and user communities. Significant research progress has been made in the relations between water footprint and agriculture, quantification of water footprint, industrial water footprint, and the transition from theory to practice. Future water footprint research needs to further enhance assessment accuracy, improve sustainability assessment methodology, develop databases, address uncertainties, and prioritize application by government and in practical sectors. More information on the symposium can be found on the water@leeds website: http://www.wateratleeds.org/conferences/2013/water-footprint-symposium.