146 research outputs found

    Hydrolases in GtoPdb v.2023.1

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    Listed in this section are hydrolases not accumulated in other parts of the Concise Guide, such as monoacylglycerol lipase and acetylcholinesterase. Pancreatic lipase is the predominant mechanism of fat digestion in the alimentary system; its inhibition is associated with decreased fat absorption. CES1 is present at lower levels in the gut than CES2 (P23141), but predominates in the liver, where it is responsible for the hydrolysis of many aliphatic, aromatic and steroid esters. Hormone-sensitive lipase is also a relatively non-selective esterase associated with steroid ester hydrolysis and triglyceride metabolism, particularly in adipose tissue. Endothelial lipase is secreted from endothelial cells and regulates circulating cholesterol in high density lipoproteins

    Hydrolases (version 2019.4) in the IUPHAR/BPS Guide to Pharmacology Database

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    Listed in this section are hydrolases not accumulated in other parts of the Concise Guide, such as monoacylglycerol lipase and acetylcholinesterase. Pancreatic lipase is the predominant mechanism of fat digestion in the alimentary system; its inhibition is associated with decreased fat absorption. CES1 is present at lower levels in the gut than CES2 (P23141), but predominates in the liver, where it is responsible for the hydrolysis of many aliphatic, aromatic and steroid esters. Hormone-sensitive lipase is also a relatively non-selective esterase associated with steroid ester hydrolysis and triglyceride metabolism, particularly in adipose tissue. Endothelial lipase is secreted from endothelial cells and regulates circulating cholesterol in high density lipoproteins

    Harmonic radar tracking reveals that honeybee drones navigate between multiple aerial leks

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    Male honeybees (drones) are thought to congregate in large numbers in particular “drone congregation areas” to mate. We used harmonic radar to record the flight paths of individual drones and found that drones favored certain locations within the landscape which were stable over two years. Drones often visit multiple potential lekking sites within a single flight and take shared flight paths between them. Flights between such sites are relatively straight and begin as early as the drone's second flight, indicating familiarity with the sites acquired during initial learning flights. Arriving at congregation areas, drones display convoluted, looping flight patterns. We found a correlation between a drone's distance from the center of each area and its acceleration toward the center, a signature of collective behavior leading to congregation in these areas. Our study reveals the behavior of individual drones as they navigate between and within multiple aerial leks

    Wheat Estimated Transcript Server (WhETS): a tool to provide best estimate of hexaploid wheat transcript sequence

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    Wheat biologists face particular problems because of the lack of genomic sequence and the three homoeologous genomes which give rise to three very similar forms for many transcripts. However, over 1.3 million available public-domain Triticeae ESTs (of which ∌850 000 are wheat) and the full rice genomic sequence can be used to estimate likely transcript sequences present in any wheat cDNA sample to which PCR primers may then be designed. Wheat Estimated Transcript Server (WhETS) is designed to do this in a convenient form, and to provide information on the number of matching EST and high quality cDNA (hq-cDNA) sequences, tissue distribution and likely intron position inferred from rice. Triticeae EST and hq-cDNA sequences are mapped onto rice loci and stored in a database. The user selects a rice locus (directly or via Arabidopsis) and the matching Triticeae sequences are assembled according to user-defined filter and stringency settings. Assembly is achieved initially with the CAP3 program and then with a single nucleotide polymorphism (SNP)-analysis algorithm designed to separate homoeologues. Alignment of the resulting contigs and singlets against the rice template sequence is then displayed. Sequences and assembly details are available for download in fasta and ace formats, respectively. WhETS is accessible at http://www4.rothamsted.bbsrc.ac.uk/whets

    HST NIR Snapshot Survey of 3CR Radio Source Counterparts II: An Atlas and Inventory of the Host Galaxies, Mergers and Companions

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    We present the second part of an H-band (1.6 microns) atlas of z<0.3 3CR radio galaxies, using the Hubble Space Telescope Near Infrared Camera and Multi-Object Spectrometer (HST NICMOS2). We present new imaging for 21 recently acquired sources, and host galaxy modeling for the full sample of 101 (including 11 archival) -- an 87% completion rate. Two different modeling techniques are applied, following those adopted by the galaxy morphology and the quasar host galaxy communities. Results are compared, and found to be in excellent agreement, although the former breaks down in the case of strongly nucleated sources. Companion sources are tabulated, and the presence of mergers, tidal features, dust disks and jets are catalogued. The tables form a catalogue for those interested in the structural and morphological dust-free host galaxy properties of the 3CR sample, and for comparison with morphological studies of quiescent galaxies and quasar host galaxies. Host galaxy masses are estimated, and found to typically lie at around 2*10^11 solar masses. In general, the population is found to be consistent with the local population of quiescent elliptical galaxies, but with a longer tail to low Sersic index, mainly consisting of low-redshift (z<0.1) and low-radio-power (FR I) sources. A few unusually disky FR II host galaxies are picked out for further discussion. Nearby external sources are identified in the majority of our images, many of which we argue are likely to be companion galaxies or merger remnants. The reduced NICMOS data are now publicly available from our website (http://archive.stsci.edu/prepds/3cr/)Comment: ApJS, 177, 148: Final version; includes revised figures 1, 15b, and section 7.5 (and other minor changes from editing process. 65 pages, inc. 17 figure

    The 1.6 micron near infrared nuclei of 3C radio galaxies: Jets, thermal emission or scattered light?

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    Using HST NICMOS 2 observations we have measured 1.6-micron near infrared nuclear luminosities of 100 3CR radio galaxies with z<0.3, by modeling and subtracting the extended emission from the host galaxy. We performed a multi-wavelength statistical analysis (including optical and radio data) of the properties of the nuclei following classification of the objects into FRI and FRII, and LIG (low-ionization galaxies), HIG (high-ionization galaxies) and BLO (broad-lined objects) using the radio morphology and optical spectra, respectively. The correlations among near infrared, optical, and radio nuclear luminosity support the idea that the near infrared nuclear emission of FRIs has a non-thermal origin. Despite the difference in radio morphology, the multi-wavelength properties of FRII LIG nuclei are statistically indistinguishable from those of FRIs, an indication of a common structure of the central engine. All BLOs show an unresolved near infrared nucleus and a large near infrared excess with respect to FRII LIGs and FRIs of equal radio core luminosity. This requires the presence of an additional (and dominant) component other than the non-thermal light. Considering the shape of their spectral energy distribution, we ascribe the origin of their near infrared light to hot circumnuclear dust. A near infrared excess is also found in HIGs, but their nuclei are substantially fainter than those of BLO. This result indicates that substantial obscuration along the line-of-sight to the nuclei is still present at 1.6 micron. Nonetheless, HIGs nuclei cannot simply be explained in terms of dust obscuration: a significant contribution from light reflected in a circumnuclear scattering region is needed to account for their multiwavelength properties.Comment: 20 pages, 16 figures. Accepted for publication on Ap

    Mapping photodissociation and shocks in the vicinity of Sgr A*

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    We have obtained maps of the molecular emission within the central five arcminutes (12 pc) of the Galactic center (GC) in selected molecular tracers: SiO(2-1), HNCO(5_{0,5}-4_{0,4}), and the J=1-->0 transition of H^{13}CO+, HN^{13}C, and C^{18}O at an angular resolution of 30" (1.2 pc). The mapped region includes the circumnuclear disk (CND) and the two surrounding giant molecular clouds (GMCs) of the Sgr A complex, known as the 20 and 50 km s^{-1} molecular clouds.Additionally, we simultaneously observed the J=2-1 and 3-2 transitions of SiO toward selected positions to estimate the physical conditions of the molecular gas. The SiO(2-1) and H^{13}CO+(1-0) emission covers the same velocity range and presents a similar distribution. In contrast, HNCO(5-4) emission appears in a narrow velocity range mostly concentrated in the 20 and 50 km s^{-1} GMCs. The HNCO column densities and fractional abundances present the highest contrast, with difference factors of ≄\geq60 and 28, respectively. Their highest values are found toward the cores of the GMCs, whereas the lowest ones are measured at the CND. SiO abundances do not follow this trend, with high values found toward the CND, as well as the GMCs. By comparing our abundances with those of prototypical Galactic sources we conclude that HNCO, similar to SiO, is ejected from grain mantles into gas-phase by nondissociative C-shocks. This results in the high abundances measured toward the CND and the GMCs. However, the strong UV radiation from the Central cluster utterly photodissociates HNCO as we get closer to the center, whereas SiO seems to be more resistant against UV-photons or it is produced more efficiently by the strong shocks in the CND. Finally, we discuss the possible connections between the molecular gas at the CND and the GMCs using the HNCO/SiO, SiO/CS, and HNCO/CS intensity ratios as probes of distance to the Central cluster.Comment: 26 pages plus 2 appendixes with additional figures. 17 figures in total. Accepted for publication in A&

    Rational Redesign of Glucose Oxidase for Improved Catalytic Function and Stability

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    Glucose oxidase (GOx) is an enzymatic workhorse used in the food and wine industries to combat microbial contamination, to produce wines with lowered alcohol content, as the recognition element in amperometric glucose sensors, and as an anodic catalyst in biofuel cells. It is naturally produced by several species of fungi, and genetic variants are known to differ considerably in both stability and activity. Two of the more widely studied glucose oxidases come from the species Aspergillus niger (A. niger) and Penicillium amagasakiense (P. amag.), which have both had their respective genes isolated and sequenced. GOx from A. niger is known to be more stable than GOx from P. amag., while GOx from P. amag. has a six-fold superior substrate affinity (KM) and nearly four-fold greater catalytic rate (kcat). Here we sought to combine genetic elements from these two varieties to produce an enzyme displaying both superior catalytic capacity and stability. A comparison of the genes from the two organisms revealed 17 residues that differ between their active sites and cofactor binding regions. Fifteen of these residues in a parental A. niger GOx were altered to either mirror the corresponding residues in P. amag. GOx, or mutated into all possible amino acids via saturation mutagenesis. Ultimately, four mutants were identified with significantly improved catalytic activity. A single point mutation from threonine to serine at amino acid 132 (mutant T132S, numbering includes leader peptide) led to a three-fold improvement in kcat at the expense of a 3% loss of substrate affinity (increase in apparent KM for glucose) resulting in a specify constant (kcat/KM) of 23.8 (mM−1 · s−1) compared to 8.39 for the parental (A. niger) GOx and 170 for the P. amag. GOx. Three other mutant enzymes were also identified that had improvements in overall catalysis: V42Y, and the double mutants T132S/T56V and T132S/V42Y, with specificity constants of 31.5, 32.2, and 31.8 mM−1 · s−1, respectively. The thermal stability of these mutants was also measured and showed moderate improvement over the parental strain

    SARS-CoV-2 evolution during treatment of chronic infection

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    The spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is critical for virus infection through the engagement of the human ACE2 protein1 and is a major antibody target. Here we show that chronic infection with SARS-CoV-2 leads to viral evolution and reduced sensitivity to neutralizing antibodies in an immunosuppressed individual treated with convalescent plasma, by generating whole-genome ultra-deep sequences for 23 time points that span 101 days and using in vitro techniques to characterize the mutations revealed by sequencing. There was little change in the overall structure of the viral population after two courses of remdesivir during the first 57 days. However, after convalescent plasma therapy, we observed large, dynamic shifts in the viral population, with the emergence of a dominant viral strain that contained a substitution (D796H) in the S2 subunit and a deletion (ΔH69/ΔV70) in the S1 N-terminal domain of the spike protein. As passively transferred serum antibodies diminished, viruses with the escape genotype were reduced in frequency, before returning during a final, unsuccessful course of convalescent plasma treatment. In vitro, the spike double mutant bearing both ΔH69/ΔV70 and D796H conferred modestly decreased sensitivity to convalescent plasma, while maintaining infectivity levels that were similar to the wild-type virus.The spike substitution mutant D796H appeared to be the main contributor to the decreased susceptibility to neutralizing antibodies, but this mutation resulted in an infectivity defect. The spike deletion mutant ΔH69/ΔV70 had a twofold higher level of infectivity than wild-type SARS-CoV-2, possibly compensating for the reduced infectivity of the D796H mutation. These data reveal strong selection on SARS-CoV-2 during convalescent plasma therapy, which is associated with the emergence of viral variants that show evidence of reduced susceptibility to neutralizing antibodies in immunosuppressed individuals
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