104 research outputs found

    Investigations of Natural Products from Bryozoa Inhabiting Aotearoa New Zealand

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    Two species of bryozoa, Pterocella vesiculosa and Plumatella repens, were investigated in an endeavour to isolate and characterise novel secondary metabolites. Analysis of fractions derived from chromatography of a dichloromethane extract of Pterocella vesiculosa, indicated the probable presence of β-carboline and pterocellin alkaloids. Continued separation led to further purification of some pterocellin alkaloids, however the characteristic ultraviolet chromatogram that is produced by pterocellins could not be found in any of the fractions analysed. Despite this, further investigations by thin layer chromatography, tandem mass spectrometry and high resolution mass spectrometry suggested structural similarities between metabolites from polar fractions and known pterocellin alkaloids. In the process of isolating these polar, pterocellin like alkaloids, a new thin layer chromatography solvent system was developed, which better differentiates the more polar metabolites in extracts compared to previously utilised solvent schemes. LCMS analysis of chromatographic fractions resulted in the detection of eight β carboline alkaloids, as well as the identification of the previously published 5 bromo-8-methoxy-1-methyl-β-carboline. Further purification of the alkaloid containing fractions by size exclusion chromatography was achieved but individual alkaloids were unable to be isolated due to time constraints associated with the project. Molecular formulae for the eight alkaloids were obtained by the use of high resolution mass spectrometry. Tandem mass spectrometry helped to confirm these formulae and also suggested the types of functional groups attached to the β-carboline skeleton. A biologically active extract of the freshwater species, Plumatella repens was investigated chemically as a continuation of a pilot study. A series of fractions from the pilot study were separated by size exclusion chromatography, with monitoring of activity against the murine P388 lymphocytic leukaemia cell line. Results of the assay indicated the presence of a highly active metabolite/s, however isolation of the metabolite/s responsible for the activity was not achieved. This was a result of delays in finding facilities to undertake the biological assays and varying degrees of P388 activity, which may suggest metabolite instability. As part of this project, tissue culture was undertaken at AgResearch, at the Ruakura Research Centre, Hamilton. A method for assay of Plumatella repens samples was developed for bioassay guided fractionation. The sterol composition of Plumatella repens was also investigated. Three sterols were identified and an additional two sterols were present, the structures of which could not be confirmed. The relative concentration of each of the sterols was also determined

    HPLC-HRMS Quantification of the Ichthyotoxin Karmitoxin from Karlodinium armiger

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    Being able to quantify ichthyotoxic metabolites from microalgae allows for the determination of ecologically-relevant concentrations that can be simulated in laboratory experiments, as well as to investigate bioaccumulation and degradation. Here, the ichthyotoxin karmitoxin, produced by Karlodinium armiger, was quantified in laboratory-grown cultures using high-performance liquid chromatography (HPLC) coupled to electrospray ionisation high-resolution time-of-flight mass spectrometry (HRMS). Prior to the quantification of karmitoxin, a standard of karmitoxin was purified from K. armiger cultures (80 L). The standard was quantified by fluorescent derivatisation using Waters AccQ-Fluor reagent and derivatised fumonisin B1 and fumonisin B2 as standards, as each contain a primary amine. Various sample preparation methods for whole culture samples were assessed, including six different solid phase extraction substrates. During analysis of culture samples, MS source conditions were monitored with chloramphenicol and valinomycin as external standards over prolonged injection sequences (>12 h) and karmitoxin concentrations were determined using the response factor of a closely eluting iturin A2 internal standard. Using this method the limit of quantification was 0.11 μg·mL−1, and the limit of detection was found to be 0.03 μg·mL−1. Matrix effects were determined with the use of K. armiger cultures grown with 13C-labelled bicarbonate as the primary carbon source

    PENGARUH MOTIVASI DAN DISIPLIN KERJA TERHADAP KINERJA PEGAWAI (Studi Pada PT. Telekomunikasi Indonesia, Tbk Wilayah Telkom Pekalongan)

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    The research aims to examine and analyze the influence of motivation and work discipline toward performance of employee in PT Telekomunikasi Indonesia Tbk. Witel Pekalongan. This research was a sample of 56 of the 125 employees of PT Telekomunikasi Indonesia Tbk. Witel Pekalongan. Samples was taken by Convenience sampling. The analysis used is multiple regression. By using signification limits about 0,05. Based on data calculation result of cost analysis used, obtained regression equality of : Y = 0,491X1 + 0,194X2 Analysis result demonstrates that motivation have a positive and significant influence between motivation to employee performance. By significant value about 0,02 (less than 0,05). Therefore, hypothesis which stated that motivation have influence to employee’s work could be accepted. There was no significant influence between work discipline to employee performance, by significant value 0.199 (greater than 0.05). Simultaneously both motivation and work dicipline have positive and significant influence to employee’s performance by f value about 18,729 (more than 0.05), therefore obtained signification value 0,000

    Spitzer Follow-up of Extremely Cold Brown Dwarfs Discovered by the Backyard Worlds: Planet 9 Citizen Science Project

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    We present Spitzer follow-up imaging of 95 candidate extremely cold brown dwarfs discovered by the Backyard Worlds: Planet 9 citizen science project, which uses visually perceived motion in multiepoch Wide-field Infrared Survey Explorer (WISE) images to identify previously unrecognized substellar neighbors to the Sun. We measure Spitzer [3.6]–[4.5] color to phototype our brown dwarf candidates, with an emphasis on pinpointing the coldest and closest Y dwarfs within our sample. The combination of WISE and Spitzer astrometry provides quantitative confirmation of the transverse motion of 75 of our discoveries. Nine of our motion-confirmed objects have best-fit linear motions larger than 1'' yr⁻¹; our fastest-moving discovery is WISEA J155349.96+693355.2 (μ ≈ 2.”15 yr⁻¹), a possible T-type subdwarf. We also report a newly discovered wide-separation (~400 au) T8 comoving companion to the white dwarf LSPM J0055+5948 (the fourth such system to be found), plus a candidate late T companion to the white dwarf LSR J0002+6357 at 5 5 projected separation (~8700 au if associated). Among our motion-confirmed targets, five have Spitzer colors most consistent with spectral type Y. Four of these five have exceptionally red Spitzer colors suggesting types of Y1 or later, adding considerably to the small sample of known objects in this especially valuable low-temperature regime. Our Y dwarf candidates begin bridging the gap between the bulk of the Y dwarf population and the coldest known brown dwarf

    Spitzer Follow-up of Extremely Cold Brown Dwarfs Discovered by the Backyard Worlds: Planet 9 Citizen Science Project

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    We present Spitzer follow-up imaging of 95 candidate extremely cold brown dwarfs discovered by the Backyard Worlds: Planet 9 citizen science project, which uses visually perceived motion in multi-epoch WISE images to identify previously unrecognized substellar neighbors to the Sun. We measure Spitzer [3.6]-[4.5] color to phototype our brown dwarf candidates, with an emphasis on pinpointing the coldest and closest Y dwarfs within our sample. The combination of WISE and Spitzer astrometry provides quantitative confirmation of the transverse motion of 75 of our discoveries. Nine of our motion-confirmed objects have best-fit linear motions larger than 1"/yr; our fastest-moving discovery is WISEA J155349.96+693355.2 (total motion ~2.15"/yr), a possible T type subdwarf. We also report a newly discovered wide-separation (~400 AU) T8 comoving companion to the white dwarf LSPM J0055+5948 (the fourth such system to be found), plus a candidate late T companion to the white dwarf LSR J0002+6357 at 5.5' projected separation (~8,700 AU if associated). Among our motion-confirmed targets, five have Spitzer colors most consistent with spectral type Y. Four of these five have exceptionally red Spitzer colors suggesting types of Y1 or later, adding considerably to the small sample of known objects in this especially valuable low-temperature regime. Our Y dwarf candidates begin bridging the gap between the bulk of the Y dwarf population and the coldest known brown dwarf.Comment: accepted for publication in The Astrophysical Journa

    Ebola virus epidemiology, transmission, and evolution during seven months in Sierra Leone

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    The 2013-2015 Ebola virus disease (EVD) epidemic is caused by the Makona variant of Ebola virus (EBOV). Early in the epidemic, genome sequencing provided insights into virus evolution and transmission and offered important information for outbreak response. Here, we analyze sequences from 232 patients sampled over 7 months in Sierra Leone, along with 86 previously released genomes from earlier in the epidemic. We confirm sustained human-to-human transmission within Sierra Leone and find no evidence for import or export of EBOV across national borders after its initial introduction. Using high-depth replicate sequencing, we observe both host-to-host transmission and recurrent emergence of intrahost genetic variants. We trace the increasing impact of purifying selection in suppressing the accumulation of nonsynonymous mutations over time. Finally, we note changes in the mucin-like domain of EBOV glycoprotein that merit further investigation. These findings clarify the movement of EBOV within the region and describe viral evolution during prolonged human-to-human transmission

    RANTES/CCL5 and Risk for Coronary Events: Results from the MONICA/KORA Augsburg Case-Cohort, Athero-Express and CARDIoGRAM Studies

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    BACKGROUND: The chemokine RANTES (regulated on activation, normal T-cell expressed and secreted)/CCL5 is involved in the pathogenesis of cardiovascular disease in mice, whereas less is known in humans. We hypothesised that its relevance for atherosclerosis should be reflected by associations between CCL5 gene variants, RANTES serum concentrations and protein levels in atherosclerotic plaques and risk for coronary events. METHODS AND FINDINGS: We conducted a case-cohort study within the population-based MONICA/KORA Augsburg studies. Baseline RANTES serum levels were measured in 363 individuals with incident coronary events and 1,908 non-cases (mean follow-up: 10.2±4.8 years). Cox proportional hazard models adjusting for age, sex, body mass index, metabolic factors and lifestyle factors revealed no significant association between RANTES and incident coronary events (HR [95% CI] for increasing RANTES tertiles 1.0, 1.03 [0.75-1.42] and 1.11 [0.81-1.54]). None of six CCL5 single nucleotide polymorphisms and no common haplotype showed significant associations with coronary events. Also in the CARDIoGRAM study (>22,000 cases, >60,000 controls), none of these CCL5 SNPs was significantly associated with coronary artery disease. In the prospective Athero-Express biobank study, RANTES plaque levels were measured in 606 atherosclerotic lesions from patients who underwent carotid endarterectomy. RANTES content in atherosclerotic plaques was positively associated with macrophage infiltration and inversely associated with plaque calcification. However, there was no significant association between RANTES content in plaques and risk for coronary events (mean follow-up 2.8±0.8 years). CONCLUSIONS: High RANTES plaque levels were associated with an unstable plaque phenotype. However, the absence of associations between (i) RANTES serum levels, (ii) CCL5 genotypes and (iii) RANTES content in carotid plaques and either coronary artery disease or incident coronary events in our cohorts suggests that RANTES may not be a novel coronary risk biomarker. However, the potential relevance of RANTES levels in platelet-poor plasma needs to be investigated in further studies

    52 Genetic Loci Influencing Myocardial Mass.

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    BACKGROUND: Myocardial mass is a key determinant of cardiac muscle function and hypertrophy. Myocardial depolarization leading to cardiac muscle contraction is reflected by the amplitude and duration of the QRS complex on the electrocardiogram (ECG). Abnormal QRS amplitude or duration reflect changes in myocardial mass and conduction, and are associated with increased risk of heart failure and death. OBJECTIVES: This meta-analysis sought to gain insights into the genetic determinants of myocardial mass. METHODS: We carried out a genome-wide association meta-analysis of 4 QRS traits in up to 73,518 individuals of European ancestry, followed by extensive biological and functional assessment. RESULTS: We identified 52 genomic loci, of which 32 are novel, that are reliably associated with 1 or more QRS phenotypes at p < 1 × 10(-8). These loci are enriched in regions of open chromatin, histone modifications, and transcription factor binding, suggesting that they represent regions of the genome that are actively transcribed in the human heart. Pathway analyses provided evidence that these loci play a role in cardiac hypertrophy. We further highlighted 67 candidate genes at the identified loci that are preferentially expressed in cardiac tissue and associated with cardiac abnormalities in Drosophila melanogaster and Mus musculus. We validated the regulatory function of a novel variant in the SCN5A/SCN10A locus in vitro and in vivo. CONCLUSIONS: Taken together, our findings provide new insights into genes and biological pathways controlling myocardial mass and may help identify novel therapeutic targets
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