275 research outputs found

    Enzyme bioprospection of marine-derived actinobacteria from the Chilean Coast and New Insight in the aechanism of keratin degradation in Streptomyces sp. G11C

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    Marine actinobacteria are viewed as a promising source of enzymes with potential technological applications. They contribute to the turnover of complex biopolymers, such as pectin, lignocellulose, chitin, and keratin, being able to secrete a wide variety of extracellular enzymes. Among these, keratinases are a valuable alternative for recycling keratin-rich waste, which is generated in large quantities by the poultry industry. In this work, we explored the biocatalytic potential of 75 marine-derived actinobacterial strains, focusing mainly on the search for keratinases. A major part of the strains secreted industrially important enzymes, such as proteases, lipases, cellulases, amylases, and keratinases. Among these, we identified two streptomycete strains that presented great potential for recycling keratin wastes—Streptomyces sp. CHA1 and Streptomyces sp. G11C. Substrate concentration, incubation temperature, and, to a lesser extent, inoculum size were found to be important parameters that influenced the production of keratinolytic enzymes in both strains. In addition, proteomic analysis of culture broths from Streptomyces sp. G11C on turkey feathers showed a high abundance and diversity of peptidases, belonging mainly to the serine and metallo-superfamilies. Two proteases from families S08 and M06 were highly expressed. These results contributed to elucidate the mechanism of keratin degradation mediated by streptomycetes

    Natural Product Genomics and Metabolomics of Marine Bacteria

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    Marine organisms are a treasure trove for the discovery of novel natural products, and, thus, marine natural products have been a focus of interest for researchers for decades. Some marine bacteria are prolific producers of natural products, occurring either free-living or, as recently shown, in symbiosis with marine animals. Recent advances in DNA sequencing have led to an enormous increase in published bacterial genomes and bioinformatics tools to analyze natural product biosynthetic potential by various “genome mining” approaches. Similarly, analytical NMR and MS methods for the characterization and comparison of metabolomes of natural product producers have advanced. Novel interdisciplinary approaches combine genomics and metabolomics data for accelerated and targeted natural product discovery. This Special Issue invites articles from both genomics- and metabolomics-driven studies on marine bacteria with a focus on natural product discovery and characterization. We particularly welcome articles that combine genomics and metabolomic approaches for the dereplication and characterization of marine bacterial natural products

    Genetic Variability and Phylogenetic Relationships within Trypanosoma cruzi I Isolated in Colombia Based on Miniexon Gene Sequences

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    Phylogenetic studies of Trypanosoma cruzi have identified the existence of two groups: T. cruzi I and T. cruzi II. There are aspects that still remain unknown about the genetic variability within the T. cruzi I group. Given its epidemiological importance, it is necessary to have a better understanding of T. cruzi transmission cycles. Our purpose was to corroborate the existence of haplotypes within the T. cruzi I group and to describe the genetic variability and phylogenetic relationships, based on single nucleotide polymorphisms (SNPs) found in the miniexon gene intergenic region, for the isolates from different hosts and epidemiological transmission cycles in Colombian regions. 31 T. cruzi isolates were molecularly characterized. Phylogenetic relationships within T. cruzi I isolates showed four haplotype groups (Ia–Id), associated with their transmission cycle. In previous studies, we reported that haplotype Ia is mainly associated with the domestic cycle and domiciliated Rhodnius prolixus. Haplotype Ib is associated with the domestic cycle and peridomestic cycle, haplotype Ic is closely related with the peridomestic cycle, and haplotype Id is strongly associated with the sylvatic cycle. The phylogenetic methodologies applied in this study are tools that bolster the associations among isolates and thus shed light on Chagas disease epidemiology

    Gauge Equivalence in Two--Dimensional Gravity

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    Two-dimensional quantum gravity is identified as a second-class system which we convert into a first-class system via the Batalin-Fradkin (BF) procedure. Using the extended phase space method, we then formulate the theory in most general class of gauges. The conformal gauge action suggested by David, Distler and Kawai is derived from a first principle. We find a local, light-cone gauge action whose Becchi-Rouet-Stora-Tyutin invariance implies Polyakov's curvature equation R=3g++=0\partial_{-}R=\partial_{-}^{3}g_{++}=0, revealing the origin of the SL(2,R)SL(2,R) Kac-Moody symmetry. The BF degree of freedom turns out be dynamically active as the Liouville mode in the conformal gauge, while in the light-cone gauge the conformal degree of freedom plays that r{\^o}le. The inclusion of the cosmological constant term in both gauges and the harmonic gauge-fixing are also considered.Comment: 30 pages, KANAZAWA 93-

    Convergence in information and communication technology (ICT) using patent analysis

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    Since the 1990s, information and communication technology (ICT) has been perceived as the critical technology for economic development, and the ICT industry itself has been growing exceptionally fast. Moreover, technology convergence in ICT has received particular attention. ICT innovations diffuse into existing products and thus come to form a new integral part of the goods. This is an exploratory research to examine technology convergence of the supply side as a firm level in the ICT sector using International Patent Classification (IPC) of 43,636 sample patents from 1995 to 2008. This study finds a degree of merger and relationships between different technology domains through the association rule mining of patent co-classification. This type of analysis helps companies to take strategies under the environment of technological trajectory change

    MAGNETO - ELECTRIC LOGIC DEVICES USING SEMICONDUCTOR CHANNEL WITH LARGE SPIN - ORBIT COUPLING

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    Antiferromagnetic magneto - electric spin - orbit read ( AF SOR ) logic devices are presented . The devices include a voltage - controlled magnetoelectric ( ME ) layer that switches polarization in response to an electric field from the applied voltage and a narrow channel conductor of a spin - orbit coupling ( SOC ) material on the ME layer . One or more sources and one or more drains , each optionally formed of ferromagnetic material , are provided on the SOC material

    CIRCUITS BASED ON MAGNETOELECTRIC TRANSISTOR DEVICES

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    Logic circuits constructed with magnetoelectric (ME) transistors are described herein. A ME logic gate device can include at least one conducting device, for example, at least one MOS transistor; and at least one ME transistor coupled to the at least one conducting device. The ME transistor can be a ME field effect transistor (ME-FET), which can be can be an anti-ferromagnetic spin-orbit read (AFSOR) device or a non - AFSOR device. The gates and logic circuits described herein can be included as standard cells in a design library. Cells of the cell library can include standard cells for a ME verter device, a ME minority gate device, a ME majority gate device, a ME full adder, a ME XNOR device, a ME XOR device, or a combination thereof

    Examining the Nucleotide Preference of the Linker Domain in Engineered Tev-mTALENs

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    Tev-mTALENs are genome-editing nucleases which combine the nuclease and linker domains of I-TevI with the DNA-binding domain of a TAL effector. The linker domain interacts with a portion of the Tev-mTALEN target site called the DNA Spacer, facilitating DNA cleavage. Linker-DNA Spacer interactions are poorly understood but necessary for Tev-mTALEN activity. I examined the DNA Spacer sequence requirements of the linker by assaying Tev-mTALEN activity on targets with mutated DNA Spacer sequences. I also performed activity assays using Tev-mTALENs with mutations to the I-TevI linker domain. My results indicate that the linker DNA Spacer sequence requirements are highly cryptic. No single nucleotide requirements exist at any position in the DNA Spacer. However, assays with mutant Tev-mTALENs have shown that small amino acid mutations to the linker domain can alter or relax the sequence requirements of Tev-mTALENs, increasing their targeting potential

    Post-Issue Patent "Quality Control": A Comparative Study of US Patent Re-examinations and European Patent Oppositions

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    We report the results of the first comparative study of the determinants and effects of patent oppositions in Europe and of re-examinations on corresponding patents issued in the United States. The analysis is based on a dataset consisting of matched EPO and US patents. Our analysis focuses on two broad technology categories - biotechnology and pharmaceuticals, and semiconductors and computer software. Within these fields, we collect data on all EPO patents for which oppositions were filed at the EPO. We also construct a random sample of EPO patents with no opposition in these technologies. We match these EPO patents with the 'equivalent' US patents covering the same invention in the United States. Using the matched sample of USPTO and EPO patents, we compare the determinants of opposition and of re-examination. Our results indicate that valuable patents are more likely to be challenged in both jurisdictions. But the rate of opposition at the EPO is more than thirty times higher than the rate of re-examination at the USPTO. Moreover, opposition leads to a revocation of the patent in about 41 percent of the cases, and to a restriction of the patent right in another 30 percent of the cases. Re-examination results in a cancellation of the patent right in only 12.2 percent of all cases. We also find that re-examination is frequently initiated by the patentholders themselves.
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