5,844 research outputs found
Peroxidase isoenzyme patterns in Vitaceae
The isolation of active cytoplasmatic enzymes has been simplified and improved. Employing this technique 313 different cultivars and species of Vitis have been analyzed for peroxidase isoenzymes in the phloem of dormant canes. Using isoelectric focusing on polyacrylamid gel layers 38 different banding patterns were obtained. Bands with isoelectric points pH 3.5 to 3.8 (type A) were found to be characteristic for Vitis vinifera cultivars (211 samples). The frequency of type A in other Vitis species is 5%. Only half of the interspecific cvs tested showed a type A pattern. Variability in neutral to basic peroxidases was useful to group V. vinifera and interspecific cultivars. The ploidy had no influence on the patterns whereas different colour variants exhibited differences. The single polymorphic isoenzyme peroxidase is sufficient to group cultivars and to discriminate between two samples
Isoelectric focusing of grapevine peroxidases as a tool for ampelography
Enzymatically active proteins have been isolated from the phloem of internodes of 71 Vitis species and cultivars and separated by thin layer electrofocusing. Peroxidases (EC 1.11.1.7.) yielded a pattern which could be differentiated into up to 8 bands within the pH range 6 through 11. The patterns obtained from different samples were congruent with ampelographic data, they are virtually identical within the families of Pinot and Silvaner, as weil as between haploid and diploid forms of one variety, even under different environmental conditions. American and Asian wild species and some interspecific hybrids show a slight shift of the isoelectric point of one enzyme band as compared to Vitis vinifera varieties
Insights into shallow magmatic processes in large silicic magma bodies: the trace element record in the Fish Canyon magma body, Colorado
Highly evolved rhyolite glass plus near-solidus mineral assemblages in voluminous, dacitic, crystal-rich ignimbrites provide an opportunity to evaluate the late magmatic evolution of granodiorite batholiths. This study reports laser-ablation ICP-MS analyses of trace element concentrations in feldspars, hornblende, biotite, titanite, zircon, magnetite, and interstitial glass of the crystal-rich Fish Canyon Tuff. The high-silica rhyolite glass is characterized by relatively high concentrations of feldspar-compatible elements (e.g., 100ppm Sr and 500ppm Ba) and low concentrations of Y (40) compared to many well-studied high-silica rhyolite glasses and whole-rock compositions. Most minerals record some trace element heterogeneities, with, in particular, one large hornblende phenocryst showing four- to six-fold core-to-rim increases in Sr and Ba coupled with a decrease in Sc. The depletions of Y and HREE in the Fish Canyon glass relative to the whole-rock composition (concentrations in glass ~30% of those in whole rocks) reflect late crystallization of phases wherein these elements were compatible. As garnet is not stable at the low-P conditions at which the Fish Canyon magma crystallized, we show that a combination of modally abundant hornblende (~4%) + titanite (~0.5-1%) and the highly polymerized nature of the rhyolitic liquid led to Y and HREE depletions in melt. Relatively high Sr and Ba contents in glass and rimward Sr and Ba increases in euhedral, concentrically zoned hornblende suggest partial feldspar dissolution and a late release of these elements to the melt as hornblende was crystallizing, in agreement with textural evidence for feldspar (and quartz) resorption. Both observations are consistent with thermal rejuvenation of the magma body prior to eruption, during which the proportion of melt increased via feldspar and quartz dissolution, even as hydrous and accessory phases were crystallizing. Sr/Y in Fish Canyon glass (13-18) is lower than the typical "adakitic” value (>40), confirming that high Sr/Y is a reliable indicator of high-pressure magma generation and/or differentiation wherein garnet is implicate
Geographic distribution of the Gerridae in Argentina (Insect, Heteroptera)
Distributional data for the fourteen species of Gerridae known to occur in Argentina are given: Eurygerris fuscinervis (herein first recorded from San Juan and San Luis Provinces), Limnogonus (Limnogonus) aduncus (herein first recorded from Formosa Prov.), L. (L.) ignotus, L. (L.)profugus, L. (Neogerris) lubricus (herein first recorded from Cordoba Prov.), Brachymetra albinerva albinerva (herein first recorded from Salta Prov.), Rheumatobates (Rheumatobates) bonariensis, R. (R.)crassifemur crassifemur (herein first recorded from Santa Fe Prov.), Halobatopsis platensis, H. spiniventris (herein first recorded from Entre Rios Prov.), Metrobates plaumanni plaumanni, M. vigilis, Ovatametra gualeguay (herein first recorded from Buenos Aires Prov.), and Trepobates taylori (herein first recorded from Jujuy Prov.). In addition distributional maps are provided. The species characteristic for each main geographic area of Argentina are: E. fuscineruis and T. taylori for the Northwestern mountainous area; L. ignotus, L. lubricus, and R. crassifemur for the Chacoan plain; L. ignotus and H. platensis for the Bonarian plain; L. ignotus, R. bonariensis, H. platensis and 0 . gualeguay for the Mesopotamian plain. E. fuscinervis and T. taylori are restricted to mountain rivers and rivulets, whereas the remaining species seem to be genuine inhabitants of either rivulets in forested hilly areas (L. aduncus, L. profugus, B. albinerva, H. spiniventris, M. plaumanni and M. vigilis), or rivers, rivulets and ponds in plains (L. ignotus, L. lubricus, R. bonariensis, R. crassifemur, H. platensis, and 0 . gualeguay). L. ignotus is a pioneer species in lowlands, readily colonizing new pools. Excepting L. aduncus, L. profugus, and 0. gualeguay which are rare, the remaining species are common in Argentina (no enough data are available for B. albinerva, M. plaumanni, and M. vigilis). Gregariousness is high in E. fuscinervis, R. bonariensis, R. crassifemur, and H. platensis, and probably also in B. albinerva. The other species mentioned seem not to be gregarious, but 0 . gualeguay appears sometimes in the dense aggregations of H. platensis, suggesting some gregarious tendency
Controls on magma permeability in the volcanic conduit during the climactic phase of the Kos Plateau Tuff eruption (Aegean Arc)
X-ray computed microtomography (µCT) was applied to pumices from the largest Quaternary explosive eruption of the active South Aegean Arc (the Kos Plateau Tuff; KPT) in order to better understand magma permeability within volcanic conduits. Two different types of pumices (one with highly elongated bubbles, tube pumice; and the other with near spherical bubbles, frothy pumice) produced synchronously and with identical chemical composition were selected for µCT imaging to obtain porosity, tortuosity, bubble size and throat size distributions. Tortuosity drops on average from 2.2 in frothy pumice to 1.5 in tube pumice. Bubble size and throat size distributions provide estimates for mean bubble size (~93-98μm) and mean throat size (~23-29μm). Using a modified Kozeny-Carman equation, variations in porosity, tortuosity, and throat size observed in KPT pumices explain the spread found in laboratory measurements of the Darcian permeability. Measured difference in inertial permeability between tube and frothy pumices can also be partly explained by the same variables but require an additional parameter related to the internal roughness of the porous medium (friction factor f 0 ). Constitutive equations for both types of permeability allow the quantification of laminar and turbulent gas escape during ascent of rhyolitic magma in volcanic conduit
Virus-like particle vaccinology, from bench to bedside.
Virus-like particles (VLPs) have become key tools in biology, medicine and even engineering. After their initial use to resolve viral structures at the atomic level, VLPs were rapidly harnessed to develop antiviral vaccines followed by their use as display platforms to generate any kind of vaccine. Most recently, VLPs have been employed as nanomachines to deliver pharmaceutically active products to specific sites and into specific cells in the body. Here, we focus on the use of VLPs for the development of vaccines with broad fields of indications ranging from classical vaccines against viruses to therapeutic vaccines against chronic inflammation, pain, allergy and cancer. In this review, we take a walk through time, starting with the latest developments in experimental preclinical VLP-based vaccines and ending with marketed vaccines, which earn billions of dollars every year, paving the way for the next wave of prophylactic and therapeutic vaccines already visible on the horizon
Prognostic value of troponins in acute coronary syndrome depends upon patient age
Peer reviewedPostprin
Justification and reporting of subgroup analyses were lacking or inadequate in randomized controlled trials
Objectives: The aim of the article was to assess the appropriateness and rationales of subgroup analyses planned in protocols of randomized controlled trials and reported in subsequent corresponding trial publications. Study Design and Setting: We searched PubMed to identify trial protocols published in journals during 2006–2017. From a total of 3,774 initially identified records, we included a random sample of 479 protocols and identified 280 trial publications corresponding to the included protocols. Results: Subgroup analyses were specified in 19% of the protocols and reported in 21% of the trial publications. Of the 94 protocols with planned subgroup analyses, 32% mentioned testing for interaction, and only three considered statistical power. Subgroup analyses were not prespecified in 56% of the 59 trial publications with subgroup analyses. Subgroup analyses were stated as prespecified in nine trial publications, without support evidence from the corresponding protocols. Subgroup analyses were often reported insufficiently for assessing the consistency of subgroup effects across studies. Justifications for subgroup analyses were provided in only four trial protocols and seven trial publications. Conclusion: Inappropriate specification and reporting of subgroup analyses remain problematic in protocols and reports of randomized controlled trials. Justifications or rationales for subgroup analyses were only rarely provided in trial protocols and reports
Ammonia toxicity to the brain and creatine.
Symptoms of hyperammonemia are age-dependent and some are reversible. Multiple mechanisms are involved. Hyperammonemia increases the uptake of tryptophan into the brain by activation of the L-system carrier while brain glutamine plays a still undefined role. The uptake of tryptophan by the brain is enhanced when the plasma levels of branched-chain amino acids competing with the other large neutral amino acids are low. Hyperammonemia increases the utilization of branched-chain amino acids in muscle when ketoglutarate is low, and this is further enhanced by glutamine depletion (as a result of therapy with ammonia scavengers like phenylbutyrate). Anorexia, most likely a serotoninergic symptom, might further aggravate the deficiency of indispensable amino acids (e.g., branched-chain and arginine). The role of increased glutamine production in astrocytes and the excitotoxic and metabotropic effects of increased extracellular glutamate have been extensively investigated and found to differ between models of acute and chronic hyperammonemia. Using an in vitro model of cultured embryonic rat brain cell aggregates, we studied the role of creatine in ammonia toxicity. Cultures exposed to ammonia before maturation showed impaired cholinergic axonal growth accompanied by a decrease of creatine and phosphocreatine, a finding not observed in mature cultures. By using different antibodies, we have shown that the phosphorylated form of the intermediate neurofilament protein is affected. Adding creatine to the culture medium partially prevents impairment of axonal growth and the presence of glia in the culture is a precondition for this protective effect. Adequate arginine substitution is essential in the treatment of urea cycle defects as creatine is inefficiently transported into the brain
On-chip polarimetry for high-throughput screening of nanoliter and smaller sample volumes
A polarimetry technique for measuring optical activity that is particularly suited for high throughput screening employs a chip or substrate (22) having one or more microfluidic channels (26) formed therein. A polarized laser beam (14) is directed onto optically active samples that are disposed in the channels. The incident laser beam interacts with the optically active molecules in the sample, which slightly alter the polarization of the laser beam as it passes multiple times through the sample. Interference fringe patterns (28) are generated by the interaction of the laser beam with the sample and the channel walls. A photodetector (34) is positioned to receive the interference fringe patterns and generate an output signal that is input to a computer or other analyzer (38) for analyzing the signal and determining the rotation of plane polarized light by optically active material in the channel from polarization rotation calculations
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