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71.
Randy I. Hecht Judy C. Morris Frederick S. Stover Lynette Fossey Charles Demarest 《Preparative biochemistry & biotechnology》2013,43(3):201-207
ABSTRACT Zone electrophoresis separations of human recombinant interleukin-3 (rh IL-3) and related proteins in untreated fused silica capillaries are presented. Results using pH 9 CHES buffer show that rh IL-3 is easily separated from a common carrier, human serum albumin, in a commercial preparation. 相似文献
72.
Xinbo Yang Erkan Aydin Hang Xu Jingxuan Kang Mohamed Hedhili Wenzhu Liu Yimao Wan Jun Peng Christian Samundsett Andres Cuevas Stefaan De Wolf 《Liver Transplantation》2018,8(20)
Minimizing carrier recombination at contact regions by using carrier‐selective contact materials, instead of heavily doping the silicon, has attracted considerable attention for high‐efficiency, low‐cost crystalline silicon (c‐Si) solar cells. A novel electron‐selective, passivating contact for c‐Si solar cells is presented. Tantalum nitride (TaN x ) thin films deposited by atomic layer deposition are demonstrated to provide excellent electron‐transporting and hole‐blocking properties to the silicon surface, due to their small conduction band offset and large valence band offset. Thin TaNx interlayers provide moderate passivation of the silicon surfaces while simultaneously allowing a low contact resistivity to n‐type silicon. A power conversion efficiency (PCE) of over 20% is demonstrated with c‐Si solar cells featuring a simple full‐area electron‐selective TaNx contact, which significantly improves the fill factor and the open circuit voltage (Voc) and hence provides the higher PCE. The work opens up the possibility of using metal nitrides, instead of metal oxides, as carrier‐selective contacts or electron transport layers for photovoltaic devices. 相似文献
73.
Stefaan P. O. Werbrouck Bruno van der Jeugt Walter Dewitte Els Prinsen Harry A. Van Onckelen Pierre C. Debergh 《Plant cell reports》1995,14(10):662-665
In Spathiphyllum floribundum Petite, which was cultured on medium containing benzyladenine (BA), uptake of this cytokinin and its conversion to 9-ß-D-ribofuranosyl-benzyladenine (9R-BA) or 9-ß-glucopyranosyl-benzyladenine (9G-BA) was monitored. BA and extremely large quantities of 9G-BA were exclusively located in the basal part of the plant (callus and meristems). 9R-BA was found in the basal part, the petioles and the leaf blades. After an acclimatisation period of 9 weeks the plants still contained high levels of 9G-BA, but BA and 9R-BA could no longer be detected after one week. The possible role of BA and its derivatives on inhibition of root initiation or irreversible chloroplast deficiency is discussed.Abbreviations 3G-BA
3-ß-glucopyranosyl-benzyladenine
- 7G-BA
7-ß-glucopyranosyl-benzyladenine
- 9G-BA
9-ß-glucopyranosyl-benzyladenine
- 9R-BA
9-ß-D-ribofuranosyl-benzyladenine
- au
absorption units
- HPLC
high-performance liquid chromatography
- LC-MS
liquid chromatography—mass spectrometry
- MeOH
methanol
- NaFeEDTA
ethylenediaminetetra-acetic acid
- NH4Ac
ammonium acetate
- PAR
photo-synthetic active radiation
- UV
ultra-violet 相似文献
74.
Stefaan Rossenu Daisy Dewitte Joël Vandekerckhove Christophe Ampe 《Journal of Protein Chemistry》1997,16(5):499-503
Phage display is a technique in which a foreign protein or peptide is presented at the surface of a (filamentous) bacteriophage. This system, developed by Smith [(1985), Science
228, 1315–1317], was originally used to create large libraries of antibodies for the purpose of selecting those that strongly bound a particular antigen. More recently it was also employed to present peptides, domains of proteins, or intact proteins at the surface of phages, again to identify high-affinity interactions with ligands. Here we want to illustrate the use of phage display, in combination with PCR saturation mutagenesis, for the study of protein–protein interactions. Rather than selecting for mutants having high affinity, we systematically investigate the binding of every variant with its natural ligand. Via a modified ELISA we can calculate a relative affinity. As a model system we chose to display thymosin 4 on the phage surface in order to study its interaction with actin. 相似文献
75.
Domperidone, a dopamine (DA) receptor antagonist with reportedly preferential actions outside of the blood-brain barrier, and haloperidol, a centrally active DA antagonist, were compared with respect to their abilities to increase the activity of dopaminergic neurons in the rat brain. The activity of nigrostriatal, mesolimbic, tuberohypophyseal and tuberoinfundibular dopamine nerves was estimated by measuring the rate of DA synthesis (dihydroxyphenylalanine accumulation following administration of an inhibitor of aromatic L-amino acid decarboxylase) in the striatum, olfactory tubercle, posterior pituitary and median eminence, respectively. In an initial study, the rates of DA synthesis in striatum, olfactory tubercle, and posterior pituitary were determined at 2, 8, and 16 h after subcutaneous administration of 0.25, 2.5, or 25 mg/kg domperidone. At the lowest dose of domperidone, DA synthesis was increased only in the posterior pituitary at 8 and 16 h; at the intermediate dose, DA synthesis increased in the posterior pituitary at 8 and 16 h and in the olfactory tubercle at 8 h. Only at 8 h after the highest dose of domperidone was DA synthesis increased in the striatum. When 2.5 mg/kg of doperidone or haloperidol were administered, DA synthesis in posterior pituitary and median eminence was increased in a similar fashion (in the latter region only at 16 h). In contrast, domperidone promoted only modest and delayed increases in DA synthesis in the olfactory tubercle and had no effect in the striatum. These results indicate that systemically administered domperidone preferentially increases DA synthesis in neurons terminating outside the blood-brain barrier, but after a pronounced delay, high doses of the drug can also activate DA neurons which project to the forebrain. 相似文献
76.
Subcutaneous injections of morphine to male rats reduced dopamine(DA) turnover (α-methyltyrosine-induced decline of DA concentrations) in the median eminence, and increased DA turnover in the striatum. Selective destruction of central 5-hydroxytryptamine(5HT)-neurons with intracerebroventricular injections of 5,7-dihydroxytryptamine, or the administration of metergoline, a putative 5HT antagonist, blocked the inhibitory effects of morphine on DA turnover in the median eminence. In the same experiments disruption of 5HT neurotransmission processes caused a similar but less dramatic antagonism of the stimulatory actions of morphine on DA turnover in the striatum. Thus, 5HT neurons play a role in mediating the effects of morphine on tuberoinfundibular and possibly on nigrostriatal DA neurons. 相似文献
77.
Qi J Lang W Geisler JG Wang P Petrounia I Mai S Smith C Askari H Struble GT Williams R Bhanot S Monia BP Bayoumy S Grant E Caldwell GW Todd MJ Liang Y Gaul MD Demarest KT Connelly MA 《Journal of lipid research》2012,53(6):1106-1116
Diacylglycerol acyltransferase (DGAT) catalyzes the final step in triglyceride (TG) synthesis. There are two isoforms, DGAT1 and DGAT2, with distinct protein sequences and potentially different physiological functions. To date, the ability to determine clear functional differences between DGAT1 and DGAT2, especially with respect to hepatic TG synthesis, has been elusive. To dissect the roles of these two key enzymes, we pretreated HepG2 hepatoma cells with (13)C(3)-D(5)-glycerol or (13)C(18)-oleic acid, and profiled the major isotope-labeled TG species by liquid chromatography tandem mass spectrometry. Selective DGAT1 and DGAT2 inhibitors demonstrated that (13)C(3)-D(5)-glycerol-incorporated TG synthesis was mediated by DGAT2, not DGAT1. Conversely, (13)C(18)-oleoyl-incorporated TG synthesis was predominantly mediated by DGAT1. To trace hepatic TG synthesis and VLDL triglyceride (VLDL-TG) secretion in vivo, we administered D(5)-glycerol to mice and measured plasma levels of D(5)-glycerol-incorporated TG. Treatment with an antisense oligonucleotide (ASO) to DGAT2 led to a significant reduction in D(5)-glycerol incorporation into VLDL-TG. In contrast, the DGAT2 ASO had no effect on the incorporation of exogenously administered (13)C(18)-oleic acid into VLDL-TG. Thus, our results indicate that DGAT1 and DGAT2 mediate distinct hepatic functions: DGAT2 is primarily responsible for incorporating endogenously synthesized FAs into TG, whereas DGAT1 plays a greater role in esterifying exogenous FAs to glycerol. 相似文献
78.
Semple G Lehmann J Wong A Ren A Bruce M Shin YJ Sage CR Morgan M Chen WC Sebring K Chu ZL Leonard JN Al-Shamma H Grottick AJ Du F Liang Y Demarest K Jones RM 《Bioorganic & medicinal chemistry letters》2012,22(4):1750-1755
The design and synthesis of a second generation GPR119-agonist clinical candidate for the treatment of diabetes is described. Compound 16 (APD597, JNJ-38431055) was selected for preclinical development based on a good balance between agonist potency, intrinsic activity and in particular on its good solubility and reduced drug-drug interaction potential. In addition, extensive in vivo studies showed a more favorable metabolic profile that may avoid the generation of long lasting metabolites with the potential to accumulate in clinical studies. 相似文献
79.
Four decades of post-agricultural forest development have caused major redistributions of soil phosphorus fractions 总被引:3,自引:0,他引:3
De Schrijver A Vesterdal L Hansen K De Frenne P Augusto L Achat DL Staelens J Baeten L De Keersmaeker L De Neve S Verheyen K 《Oecologia》2012,169(1):221-234
Fertilisation of agricultural land causes an accumulation of nutrients in the top soil layer, among which phosphorus (P) is particularly persistent. Changing land use from farmland to forest affects soil properties, but changes in P pools have rarely been studied despite their importance to forest ecosystem development. Here, we describe the redistributions of the P pools in a four-decadal chronosequence of post-agricultural common oak (Quercus robur L.) forests in Belgium and Denmark. The aim was to assess whether forest age causes a repartitioning of P throughout the various soil P pools (labile P, slowly cycling P and occluded P); in particular, we addressed the time-related alterations in the inorganic versus organic P fractions. In less than 40 years of oak forest development, significant redistributions have occurred between different P fractions. While both the labile and the slowly cycling inorganic P fractions significantly decreased with forest age, the organic fractions significantly increased. The labile P pool (inorganic + organic), which is considered to be the pool of P most likely to contribute to plant-available P, significantly decreased with forest age (from >20 to <10% of total P), except in the 0-5 cm of topsoil, where labile P remained persistently high. The shift from inorganic to organic P and the shifts between the different inorganic P fractions are driven by biological processes and also by physicochemical changes related to forest development. It is concluded that the organic labile P fraction, which is readily mineralisable, should be taken into account when studying the bioavailable P pool in forest ecosystems. 相似文献
80.
Tang Y Zhou L Gunnet JW Wines PG Cryan EV Demarest KT 《Biochemical and biophysical research communications》2006,345(1):29-37
HM74A is a G protein-coupled receptor for nicotinic acid (niacin), which has been used clinically to treat dyslipidemia for decades. The molecular mechanisms whereby niacin exerts its pleiotropic effects on lipid metabolism remain largely unknown. In addition, the most common side effect in niacin therapy is skin flushing that is caused by prostaglandin release, suggesting that the phospholipase A(2) (PLA(2))/arachidonic acid (AA) pathway is involved. Various eicosanoids have been shown to activate peroxisome-proliferator activated receptors (PPAR) that play a diverse array of roles in lipid metabolism. To further elucidate the potential roles of HM74A in mediating the therapeutic effects and/or side effects of niacin, we sought to explore the signaling events upon HM74A activation. Here we demonstrated that HM74A synergistically enhanced UTP- and bradykinin-mediated AA release in a pertussis toxin-sensitive manner in A431 cells. Activation of HM74A also led to Ca(2+)-mobilization and enhanced bradykinin-promoted Ca(2+)-mobilization through Gi protein. While HM74A increased ERK1/2 activation by the bradykinin receptor, it had no effects on UTP-promoted ERK1/2 activation.Furthermore, UTP- and bradykinin-mediated AA release was significantly decreased in the presence of both MAPK kinase inhibitor PD 098059 and PKC inhibitor GF 109203X. However, the synergistic effects of HM74A were not dramatically affected by co-treatment with both inhibitors, indicating the cross-talk occurred at the receptor level. Finally, stimulation of A431 cells transiently transfected with PPRE-luciferase with AA significantly induced luciferase activity, mimicking the effects of PPARgamma agonist rosiglitazone, suggesting that alteration of AA signaling pathway can regulate gene expression via endogenous PPARs. 相似文献