A systematic study of North American Angelica species (Apiaceae) based on nrDNA ITS and cpDNA sequences and fruit morphology

Angelica is a taxonomically complex genus widespread throughout the North Temperate Zone. Previous phylogenetic studies of the genus have focused primarily on its East Asian species. The relationships among its North American members, the monophyly of these species, and the value of fruit morphology in circumscribing its taxa have yet to be examined. This study represents the most comprehensive sampling of Angelica to date (100 species) and includes all 26 species in North America. Relationships are inferred using Bayesian inference, maximum likelihood, and maximum parsimony analyses of ITS sequences and, for multiple accessions of each North American species, cpDNA ndhF-rpl32, rpl32-trnL, and psbM-psbD sequences. The fruit morphological characters examined were those considered phylogenetically important in East Asian Angelica. The results revealed that the North American species fell into three major clades: North American Angelica clade, Archangelica clade, and the Eurasian Angelica clade. Angelica dawsonii has affinities with Lomatium brandegeei. Fourteen species within the North American Angelica clade were strongly supported as monophyletic. Two paraphyletic species resulted in new combinations in A. lineariloba and A. venenosa. Conflict between the ITS-derived and cpDNA-derived phylogenies and the lack of resolution in portions of the trees may be due to chloroplast capture and rapid species radiation. Fruit morphology supported some interspecific relationships based on molecular data, and relationships revealed by ITS and cpDNA data were roughly in accordance with fruit classification type and geographic distribution region, respectively. A diagnostic key based on fruit morphology is provided for the identification of the North American Angelica taxa.     

Salt-induced changes in the plasma membrane proteome of the halotolerant alga Dunaliella salina as revealed by blue native gel electrophoresis and nano-LC-MS/MS analysis

The halotolerant alga Dunaliella salina is a recognized model photosynthetic organism for studying plant adaptation to high salinity. The adaptation mechanisms involve major changes in the proteome composition associated with energy metabolism and carbon and iron acquisition. To clarify the molecular basis for the remarkable resistance to high salt, we performed a comprehensive proteomics analysis of the plasma membrane. Plasma membrane proteins were recognized by tagging intact cells with a membrane-impermeable biotin derivative. Proteins were resolved by two-dimensional blue native/SDS-PAGE and identified by nano-LC-MS/MS. Of 55 identified proteins, about 60% were integral membrane or membrane-associated proteins. We identified novel surface coat proteins, lipid-metabolizing enzymes, a new family of membrane proteins of unknown function, ion transporters, small GTP-binding proteins, and heat shock proteins. The abundance of 20 protein spots increased and that of two protein spots decreased under high salt. The major salt-regulated proteins were implicated in protein and membrane structure stabilization and within signal transduction pathways. The migration profiles of native protein complexes on blue native gels revealed oligomerization or co-migration of major surface-exposed proteins, which may indicate mechanisms of stabilization at high salinity.     

Sustained release varnish containing chlorhexidine for prevention of Streptococcus mutans biofilm formation on voice prosthesis surface: an in vitro study

International Microbiology - In this study, we aimed to develop a novel, sustained release varnish (SRV) for voice prostheses (VP) releasing chlorhexidine (CHX), for the prevention of biofilm...     

Carbamazepine produces nonspecific effects on cocaine self-administration in rats.

Anecdotal evidence in humans suggest that carbamazepine suppresses cocaine-induced rush and craving. Such claims are unsupported in controlled trials using a placebo control. In the present study, rats were trained to self-administer i.v. cocaine in daily 2-hr sessions in which every tenth lever press delivered 1 mg/kg cocaine. After responding was stable, they were injected before each session with the vehicle for 2 days followed by carbamazepine for 2 days. At a 7 mg/kg dose, carbamazepine was without effect, whereas 15 mg/kg suppressed responding for cocaine only on the second (day 4) day of carbamazepine treatment. With 4 consecutive days of treatment, carbamazepine (15 mg/kg) reduced cocaine-maintained responding slightly, but significantly. In another group of animals trained to lever-press for food reinforcement, carbamazepine (15 mg/kg) also significantly decreased the rate of responding, suggesting that the suppression of responding was not specific to cocaine-reinforced behavior.     

The gp91phox component of NADPH oxidase is not the voltage-gated proton channel in phagocytes, but it helps

During the "respiratory burst," the NADPH oxidase complex of phagocytes produces reactive oxygen species that kill bacteria and other invaders (Babior, B. M. (1999) Blood 93, 1464-1476). Electron efflux through NADPH oxidase is electrogenic (Henderson, L. M., Chappell, J. B., and Jones, O. T. G. (1987) Biochem. J. 246, 325-329) and is compensated by H(+) efflux through proton channels that reportedly are contained within the gp91(phox) subunit of NADPH oxidase. To test whether gp91(phox) functions as a proton channel, we studied H(+) currents in granulocytes from X-linked chronic granulomatous disease patients lacking gp91(phox) (X-CGD), the human myelocytic PLB-985 cell line, PLB-985 cells in which gp91(phox) was knocked out by gene targeting (PLB(KO)), and PLB-985 knockout cells re-transfected with gp91(phox) (PLB(91)). H(+) currents in unstimulated PLB(KO) cells had amplitude and gating kinetics similar to PLB(91) cells. Furthermore, stimulation with the phorbol ester phorbol 12-myristate 13-acetate increased H(+) currents to a similar extent in X-CGD, PLB(KO), and PLB(91) cells. Thus, gp91(phox) is not the proton channel in unstimulated phagocytes and does not directly mediate the increase of proton conductance during the respiratory burst. Changes in H(+) channel gating kinetics during NADPH oxidase activity are likely crucial to the activation of H(+) flux during the respiratory burst.     

Role of DNA end distortion in catalysis by avian sarcoma virus integrase.

Retroviral integrase (IN) recognizes linear viral DNA ends and introduces nicks adjacent to a highly conserved CA dinucleotide usually located two base pairs from the 3'-ends of viral DNA (the "processing" reaction). In a second step, the same IN active site catalyzes the insertion of these ends into host DNA (the "joining" reaction). Both DNA sequence and DNA structure contribute to specific recognition of viral DNA ends by IN. Here we used potassium permanganate modification to show that the avian sarcoma virus IN catalytic domain is able to distort viral DNA ends in vitro. This distortion activity is consistent with both unpairing and unstacking of the three terminal base pairs, including the processing site adjacent to the conserved CA. Furthermore, the introduction of mismatch mutations that destabilize the viral DNA ends were found to stimulate the IN processing reaction as well as IN-mediated distortion. End-distortion activity was also observed with mutant or heterologous DNA substrates. However, further analyses showed that using Mn(2+) as a cofactor, processing site specificity of these substrates was also maintained. Our results support a model whereby unpairing and unstacking of the terminal base pairs is a required step in the processing reaction. Furthermore, these results are consistent with our previous observations indicating that unpairing of target DNA promotes the joining reaction.     

Plasma membrane electron transport coupled to Na(+) extrusion in the halotolerant alga Dunaliella

The halotolerant alga Dunaliella adapts to exceptionally high salinity and maintains low [Na(+)](in) at hypersaline solutions, suggesting that it possesses efficient mechanisms for regulating intracellular Na(+). In this work we examined the possibility that Na(+) export in Dunaliella is linked to a plasma membrane electron transport (redox) system. Na(+) extrusion was induced in Dunaliella cells by elevation of intracellular Na(+) with Na(+)-specific ionophores. Elevation of intracellular Na(+) was found to enhance the reduction of an extracellular electron acceptor ferricyanide (FeCN). The quinone analogs NQNO and dicumarol inhibited FeCN reduction and led to accumulation of Na(+) by inhibition of Na(+) extrusion. These inhibitors also diminished the plasma membrane potential in Dunaliella. Anaerobic conditions elevated, whereas FeCN partially decreased intracellular Na(+) content. Cellular NAD(P)H level decreased upon enhancement of plasma membrane electron transport. These results are consistent with the operation of an electrogenic NAD(P)H-driven redox system coupled to Na(+) extrusion in Dunaliella plasma membrane. We propose that redox-driven Na(+) extrusion and recycling in Dunaliella evolved as means of adaptation to hypersaline environments.