The pulsation spectrum of VX Hydrae

We present the results of a two-year, multisite observing campaign investigating the high-amplitude delta Scuti star VX Hydrae during the 2006 and 2007 observing seasons. The final data set consists of nearly 8500 V-band observations spanning HJD 2453763.6 to 2454212.7 (2006 January 28 to 2007 April 22). Separate analyses of the two individual seasons of data yield 25 confidently-detected frequencies common to both data sets, of which two are pulsation modes, and the remaining 23 are Fourier harmonics or beat frequencies of these two modes. The 2006 data set had five additional frequencies with amplitudes less than 1.5 mmag, and the 2007 data had one additional frequency. Analysis of the full 2006-2007 data set yields 22 of the 25 frequencies found in the individual seasons of data. There are no significant peaks in the spectrum other than these between 0 and 60 c/d. The frequencies of the two main pulsation modes derived from the 2006 and 2007 observing seasons individually do not differ at the level of 3-sigma, and thus we find no conclusive evidence for period change over the span of these observations. However, the amplitude of f(1) = 5.7898 c/d changed significantly between the two seasons, while the amplitude of f(0) = 4.4765 c/d remained constant; amplitudes of the Fourier harmonics and beat frequencies of f(1) also changed. Similar behavior was seen in the 1950s, and it is clear that VX Hydrae undergoes significant amplitude changes over time.Comment: 14 pages, 5 figures, published in Publications of the Astronomical Society of the Pacific, v.121, p.1076 (October 2009

The physico-chemical properties of strawberry tree (Arbutus unedo L.) fruits

The physico-chemical properties of ripe fruits of strawberry tree (Arbutus unedo L.) were determined. The water content, ash, crude fat, proteins, total phenols, sugar, and the content of vitamin C were determined in ripe strawberry tree fruits. Fruits contain 46.7 % of water, 23.5 % of soluble solids, 0.48 % of ash, 118.61 mg/100 g of potassium, 20.63 mg/100 g of sodium, 36.05 mg/100 g of calcium, 9.66 mg/100 g of magnesium, 1.29 mg/100 g of iron, 19.99 mg/100 g of phosphorus, 0.45 mg/100 g of zinc, < 0.99 mg/100 g of manganese, < 0.99 mg/100 g of chromium, < 0.10 mg/100 g of nickel, < 1.32 mg/100 g of lead and < 0.10 mg/100 g of cadmium. Among nutritionally important components found in fruits were: total fat (0.43 %), proteins (0.82 %), fibres (18.5 g/100 g) of which 14.3 g/100g was insoluble and 4.19 g/100 g was soluble fibre, titratable acids (5.1 mg/100 g), glucose (6.2 g/100 g) and fructose (17.2 g/100 g). Ripe fruits contained 271.5 mg/100 g vitamin C, of which 255.3 mg/ 100 g was L-ascorbic acid and 16.2 mg/100 g was dehydroascorbic acid

Phenolic Compounds in Extracts from Eucalyptus globulus Leaves and Calendula officinalis Flowers

Selection of the optimal solvent system for extraction of the phenolics from Eucalyptus globules leaves and Calendula officinalis flowers, determination of the reducing potential and identification of the phenolics in these extracts was performed. The highest content of phenolics was obtained for methanol: water extracts from both sources. All of the Eucalyptus leaf extracts had higher reducing potential than those from the Calendula flowers. Solid-phase purification of the crude extracts removed 57% to 78% of the compounds in the crude extracts. The reducing potential of the purified extracts varied from 0.17 to 2.92 mg caffeic acid/g dry weight. The extracts from Eucalyptus leaves and Calendula flowers both contained chlorogenic acid, rutin and quercetin 3-glucuronide. Ellagic acid derivatives were identified only in the leaves of Eucalyptus, while beside caffeic acid and salicylic acid, quercetin 3-glucuronide, and pinobanksin 3-acetate was found in the Calendula flower extract for the first time.Fil: Dos Santos Ferreira, Cristina Isabel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias; ArgentinaFil: Pereyra, A.. University of Ljubljana. Biotechnical Faculty; EsloveniaFil: Patriarca, Andrea Rosana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Micología y Botánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Micología y Botánica; ArgentinaFil: Mazzobre, Maria Florencia. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Polak, T.. University of Ljubljana. Biotechnical Faculty; EsloveniaFil: Abram, V.. University of Ljubljana. Biotechnical Faculty; EsloveniaFil: Buera, Maria del Pilar. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Poklar Ulrih, N.. University of Ljubljana. Biotechnical Faculty; Esloveni

Hypoxia Sensitive Metal β-Ketoiminate Complexes Showing Induced Single Strand DNA Breaks and Cancer Cell Death by Apoptosis

A series of ruthenium and iridium complexes have been synthesised and characterised with 20 novel crystal structures discussed. The library of β-ketoiminate complexes has been shown to be active against MCF-7 (human breast carcino-ma), HT-29 (human colon carcinoma), A2780 (human ovarian carcinoma) and A2780cis (cisplatin resistant human ovarian carcinoma) cell lines, with selected complexes being more than three times as active as cisplatin against the A2780cis cell line. Complexes have also been shown to be highly active under hypoxic conditions, with the activities of some complexes increasing with a decrease in O2 concentration. The enzyme thioredoxin reductase is over-expressed in cancer cells and complexes reported herein have the advantage of inhibiting this enzyme, with IC50 values measured in the nanomolar range. The anti-cancer activity of these complexes was further investigated to determine whether activity is due to effects on cellular growth or cell survival. The complexes were found to induce significant cancer cell death by apoptosis with levels induced correlating closely with activity in chemosensitivity studies. As a possible cause of cell death, the ability of the complexes to induce damage to cellular DNA was also assessed. The complexes failed to induce double strand DNA break or DNA crosslinking but induced significant levels of single DNA strand breaks indi-cating a different mechanism of action to cisplatin

Differential Scanning Fluorometry Signatures as Indicators of Enzyme Inhibitor Mode of Action: Case Study of Glutathione S-Transferase

Differential scanning fluorometry (DSF), also referred to as fluorescence thermal shift, is emerging as a convenient method to evaluate the stabilizing effect of small molecules on proteins of interest. However, its use in the mechanism of action studies has received far less attention. Herein, the ability of DSF to report on inhibitor mode of action was evaluated using glutathione S-transferase (GST) as a model enzyme that utilizes two distinct substrates and is known to be subject to a range of inhibition modes. Detailed investigation of the propensity of small molecule inhibitors to protect GST from thermal denaturation revealed that compounds with different inhibition modes displayed distinct thermal shift signatures when tested in the presence or absence of the enzyme's native co-substrate glutathione (GSH). Glutathione-competitive inhibitors produced dose-dependent thermal shift trendlines that converged at high compound concentrations. Inhibitors acting via the formation of glutathione conjugates induced a very pronounced stabilizing effect toward the protein only when GSH was present. Lastly, compounds known to act as noncompetitive inhibitors exhibited parallel concentration-dependent trends. Similar effects were observed with human GST isozymes A1-1 and M1-1. The results illustrate the potential of DSF as a tool to differentiate diverse classes of inhibitors based on simple analysis of co-substrate dependency of protein stabilization

Enzymatic Degradation of PrPSc by a Protease Secreted from Aeropyrum pernix K1

BACKGROUND: An R30 fraction from the growth medium of Aeropyrum pernix was analyzed for the protease that can digest the pathological prion protein isoform (PrP(Sc)) from different species (human, bovine, deer and mouse). METHODOLOGY/PRINCIPAL FINDINGS: Degradation of the PrP(Sc) isoform by the R30 fraction and the purified protease was evaluated using the 6H4 anti-PrP monoclonal antibody. Fragments from the N-terminal and C-terminal of PrP(Sc) were also monitored by Western blotting using the EB8 anti-PrP monoclonal antibody, and by dot blotting using the C7/5 anti-PrP monoclonal antibody, respectively. For detection of smaller peptides from incomplete digestion of PrP(Sc), the EB8 monoclonal antibody was used after precipitation with sodium phosphotungstate. Characterization of the purified active protease from the R30 fraction was achieved, through purification by fast protein liquid chromatography, and identification by tandem mass spectrometry the serine metalloprotease pernisine. SDS-PAGE and zymography show the purified pernisine plus its proregion with a molecular weight of ca. 45 kDa, and the mature purified pernisine as ca. 23 kDa. The purified pernisine was active between 58 °C and 99 °C, and between pH 3.5 and 8.0. The temperature and pH optima of the enzymatic activity of the purified pernisine in the presence of 1 mM CaCl(2) were 105 °C ± 0.5 °C and pH 6.5 ± 0.2, respectively. CONCLUSIONS/SIGNIFICANCE: Our study has identified and characterized pernisine as a thermostable serine metalloprotease that is secreted from A. pernix and that can digest the pathological prion protein PrP(Sc)

Simulation of Small Peptide Using Combined Wang-Landau-Transition Matrix Monte Carlo Algorithm

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