Metal Content of Metallo-β-lactamase L1 Is Determined by the Bioavailability of Metal Ions

In an effort to probe whether the metal content of metallo-β-lactamase L1 is affected by metal ion bioavailability, L1 was overexpressed as mature protein (M-L1) and full-length (FL-L1) analogues, and the analogues were characterized with metal analyses, kinetics, and EPR spectroscopy. FL-L1, containing the putative leader sequence, was localized in the periplasm of Escherichia coli and shown to bind Zn(II) preferentially. The metal content of FL-L1 could be altered if the enzyme was overexpressed in minimal medium containing Fe and Mn, and surprisingly, an Fe-binding analogue was obtained. On the other hand, M-L1, lacking the putative leader sequence, was localized in the cytoplasm of E. coli and shown to bind various amounts of Fe and Zn(II), and like FL-L1, the metal content of the resulting enzyme could be affected by the amount of metal ions in the growth medium. L1 was refolded in the presence of Fe, and a dinuclear Fe-containing analogue of L1 was obtained, although this analogue is catalytically inactive. EPR spectra demonstrate the presence of an antiferromagnetically coupled Fe(III)Fe(II) center in Fe-containing L1 and suggest the presence of a Fe(III)Zn(II) center in M-L1. Metal analyses on the cytoplasmic and periplasmic fractions of E. coli showed that the concentration of metal ions in the periplasm is not tightly controlled and increases as the concentration of metal ions in the growth medium increases. In contrast, the concentration of Zn(II) in the cytoplasm is tightly controlled while that of Fe is less so

A Calibration of NICMOS Camera 2 for Low Count-Rates

NICMOS 2 observations are crucial for constraining distances to most of the existing sample of z > 1 SNe Ia. Unlike the conventional calibration programs, these observations involve long exposure times and low count rates. Reciprocity failure is known to exist in HgCdTe devices and a correction for this effect has already been implemented for high and medium count-rates. However observations at faint count-rates rely on extrapolations. Here instead, we provide a new zeropoint calibration directly applicable to faint sources. This is obtained via inter-calibration of NIC2 F110W/F160W with WFC3 in the low count-rate regime using z ~ 1 elliptical galaxies as tertiary calibrators. These objects have relatively simple near-IR SEDs, uniform colors, and their extended nature gives superior signal-to-noise at the same count rate than would stars. The use of extended objects also allows greater tolerances on PSF profiles. We find ST magnitude zeropoints (after the installation of the NICMOS cooling system, NCS) of 25.296 +- 0.022 for F110W and 25.803 +- 0.023 for F160W, both in agreement with the calibration extrapolated from count-rates 1,000 times larger (25.262 and 25.799). Before the installation of the NCS, we find 24.843 +- 0.025 for F110W and 25.498 +- 0.021 for F160W, also in agreement with the high-count-rate calibration (24.815 and 25.470). We also check the standard bandpasses of WFC3 and NICMOS 2 using a range of stars and galaxies at different colors and find mild tension for WFC3, limiting the accuracy of the zeropoints. To avoid human bias, our cross-calibration was "blinded" in that the fitted zeropoint differences were hidden until the analysis was finalized.Comment: Accepted for Publication in the Astronomical Journal. New version contains added referenc

Laser treatment monitoring with reflectance confocal microscopy

Laser treatments have become popular in Dermatology. In parallel to technologic development enabling the availability of different laser wavelengths, non-invasive skin imaging techniques, such as reflectance confocal microscopy (RCM), have been used to explore morphologic and qualitative skin characteristics. Specifically, RCM can be applied to cosmetically sensitive skin areas such as the face, without the need for skin biopsies. For these reasons, apart from its current use in skin cancer diagnosis, our systematic review reveals how RCM can be employed in the field of laser treatment monitoring, being particularly suitable for the evaluation of variations in epidermis and dermis, and pigmentary and vascular characteristics of the skin. This systematic review article aims to provide an overview on current applications of RCM laser treatment monitoring, while describing RCM features identified for different applications. Studies on human subjects treated with laser treatments, monitored with RCM, were included in the current systematic review. Five groups of treatments were identified and described: skin rejuvenation, scar tissue, pigmentary disorders, vascular disorders and other. Interestingly, RCM can assist treatments with lasers targeting all chromophores in the skin and exploiting laser induced optical breakdown. Treatment monitoring encompasses assessment at baseline and examination of changes after treatment, therefore revealing details in morphologic alterations underlying different skin conditions and mechanisms of actions of laser therapy, as well as objectify results after treatment

Effects of β2-receptor stimulation by indacaterol in chronic heart failure treated with selective or non-selective β-blockers: a randomized trial

Alveolar \u3b22-receptor blockade worsens lung diffusion in heart failure (HF). This effect could be mitigated by stimulating alveolar \u3b22-receptors. We investigated the safety and the effects of indacaterol on lung diffusion, lung mechanics, sleep respiratory behavior, cardiac rhythm, welfare, and exercise performance in HF patients treated with a selective (bisoprolol) or a non-selective (carvedilol) \u3b2-blocker. Study procedures were performed before and after indacaterol and placebo treatments according to a cross-over, randomized, double-blind protocol in forty-four patients (27 on bisoprolol and 17 on carvedilol). No differences between indacaterol and placebo were observed in the whole population except for a significantly higher VE/VCO2 slope and lower maximal PETCO2 during exercise with indacaterol, entirely due to the difference in the bisoprolol group (VE/VCO2 31.8\u2009\ub1\u20095.9 vs. 28.5\u2009\ub1\u20095.6, p\u2009<\u20090.0001 and maximal PETCO2 36.7\u2009\ub1\u20095.5 vs. 37.7\u2009\ub1\u20095.8\u2009mmHg, p\u2009<\u20090.02 with indacaterol and placebo, respectively). In carvedilol, indacaterol was associated with a higher peak heart rate (119\u2009\ub1\u200934 vs. 113\u2009\ub1\u200930 bpm, with indacaterol and placebo) and a lower prevalence of hypopnea during sleep (3.8 [0.0;6.3] vs. 5.8 [2.9;10.5] events/hour, with indacaterol and placebo). Inhaled indacaterol is well tolerated in HF patients, it does not influence lung diffusion, and, in bisoprolol, it increases ventilation response to exercise

Microthyriaceae sp., an endophytic fungus

In screening for natural products with antiparasitic activity, an endophytic fungus, strain F2611, isolated from above-ground tissue of the tropical grass Paspalum conjugatum (Poaceae) in Panama, was chosen for bioactive principle elucidation. Cultivation on malt extract agar (MEA) followed by bioassayguided chromatographic fractionation of the extract led to the isolation of the new polyketide integrasone B (1) and two known mycotoxins, sterigmatocystin (2) and secosterigmatocystin (3). Sterigmatocystin (2) was found to be the main antiparasitic compound in the fermentation extract of this fungus, possessing potent and selective antiparasitic activity against Trypanosoma cruzi, the cause of Chagas disease, with an IC50 value of 0 13 lmol l 1. Compounds 2 and 3 showed high cytotoxicity against Vero cells (IC50 of 0 06 and 0 97 lmol l 1, respectively). The new natural product integrasone B (1), which was co-purified from the active fractions, constitutes the second report of a natural product possessing an epoxyquinone with a lactone ring and exhibited no significant biological activity. Strain F2611 represents a previously undescribed taxon within the Microthyriaceae (Dothideomycetes, AscomycotaIn screening for natural products with antiparasitic activity, an endophytic fungus, strain F2611, isolated from above-ground tissue of the tropical grass Paspalum conjugatum (Poaceae) in Panama, was chosen for bioactive principle elucidation. Cultivation on malt extract agar (MEA) followed by bioassayguided chromatographic fractionation of the extract led to the isolation of the new polyketide integrasone B (1) and two known mycotoxins, sterigmatocystin (2) and secosterigmatocystin (3). Sterigmatocystin (2) was found to be the main antiparasitic compound in the fermentation extract of this fungus, possessing potent and selective antiparasitic activity against Trypanosoma cruzi, the cause of Chagas disease, with an IC50 value of 0 13 lmol l 1. Compounds 2 and 3 showed high cytotoxicity against Vero cells (IC50 of 0 06 and 0 97 lmol l 1, respectively). The new natural product integrasone B (1), which was co-purified from the active fractions, constitutes the second report of a natural product possessing an epoxyquinone with a lactone ring and exhibited no significant biological activity. Strain F2611 represents a previously undescribed taxon within the Microthyriaceae (Dothideomycetes, AscomycotaLaboratory of Tropical Bioorganic Chemistry, Faculty of Natural Exact Sciences and Technology, University of Panama, Panama City, Republic of Panama Smithsonian Tropical Research Institute, Balboa, Panama City, Republic of Panama Centro de Biodiversidade, Gen omica Integrativa e Funcional (BioFIG), Universidade de Lisboa, Faculdade de Ci^encias, Edif ıcio ICAT/TecLabs, Campus da FCUL, Campo Grande, Lisboa, Portugal Institute for Advanced Scientific Investigation and High Technology Services, National Secretariat of Science, Technology, and Innovation, City of Knowledge, Panama City, Republic of Panama School of Plant Sciences, The University of Arizona, Tucson, AZ, USA Department of Biology, University of Utah, Salt Lake City, UT, USA Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, US

Comparison of the in vitro invasive capabilities of Plasmodium falciparum schizonts isolated by Percoll gradient or using magnetic based separation

<p>Abstract</p> <p>Background</p> <p>Percoll gradient centrifugation is often used for synchronization, enrichment, or isolation of a particular stage of <it>Plasmodium falciparum</it>. However, Percoll, a hyperosmotic agent, may have harmful effects on the parasites. Magnetic bead column (MBC) separation has been used as an alternative. This is a report of a head-to-head comparison of the <it>in vitro </it>invasive capabilities of parasites isolated by either of the two methods.</p> <p>Methods</p> <p>The <it>P. falciparum </it>laboratory strain isolate 7G8 was grown <it>in vitro </it>using standard procedures and synchronized using 5% sorbitol. On separate days when the schizont parasitaemia was >1%, the culture was split and half was processed by Percoll gradient centrifugation and the other half by magnetic bead column separation. Both processed parasites were placed back in culture and allowed to invade new uninfected erythrocytes.</p> <p>Results</p> <p>In 10 paired assays, the mean efficiency of invasion of 7G8 parasites treated by Percoll gradient centrifugation was 35.8% that of those treated by magnetic bead column separation (95% CI, p = 0.00067) A paired <it>t </it>test with two tails was used for these comparisons.</p> <p>Conclusions</p> <p>In this comparison, magnetic bead column separation of 7G8 schizonts resulted in higher viability and efficiency of invasion than utilizing Percoll gradient centrifugation.</p

Rest-Frame R-band Lightcurve of a z~1.3 Supernova Obtained with Keck Laser Adaptive Optics

We present Keck diffraction limited H-band photometry of a z~1.3 Type Ia supernova (SN) candidate, first identified in a Hubble Space Telescope (HST) search for SNe in massive high redshift galaxy clusters. The adaptive optics (AO) data were obtained with the Laser Guide Star facility during four observing runs from September to November 2005. In the analysis of data from the observing run nearest to maximum SN brightness, the SN was found to have a magnitude H=23.9 +/- 0.14 (Vega). We present the H-band (approximately rest-frame R) light curve and provide a detailed analysis of the AO photometric uncertainties. By constraining the aperture correction with a nearby (4" separation) star we achieve 0.14 magnitude photometric precision, despite the spatially varying AO PSF.Comment: 11 pages, 8 figures, Accepted for Publication in AJ Updated the citations, fixed typo