370 research outputs found

    Closing the Auditor Loophole: Towards a More Perfect Work-Product Waiver Doctrine

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    The Supreme Court created strong protections for the attorney’s thought processes and analysis in Hickman v. Taylor. However, the Court in Arthur Young & Co. created a loophole enabling opposing lawyers to access the lawyer’s thought processes and legal strategies. This loophole was created when the Court allowed discovery of an auditor’s tax workpapers, and lower courts then interpreted this decision to imply that disclosing information to the outside auditor constitutes a waiver of attorney work-product protections. This loophole can be corrected through a Congressional statute that impacts the Federal Rules of Evidence, which would protect communications between outside auditors and their clients for legally required audits. If Congress fails to act, then courts should hold that disclosure of documents to outside auditors as part of a Securities and Exchange Commission required audit does not waive attorney work-product protections

    Arms Control 2.0: Updating the Cyberweapon Arms Control Framework

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    This Note analyzes multiple problems with the existing arms control framework for cyberweapons as well as surveillance technology and calls for four specific areas of reform. First, the existing framework does not specifically enumerate the software controlled under existing arms control treaties, which can lead to gaps in international export control compliance. Cyberweapons should be enumerated with greater specificity to prevent confusing and disjointed implementation by states. Second, the divide between Wassenaar and Shanghai Cooperation Organization conceptions of what constitutes a cyberweapon reduces the effectiveness of international control because nations do not share an agreed upon cyberweapon definition. States should form a multilateral treaty utilizing a shared definition to ensure cyberweapon exports are regulated by a treaty and include a greater diversity of countries covering a larger share of this market. Third, the Wassenaar Arrangement, the current treaty regulating many cyberweapon exports, fails to impose strict controls on cyberweapons and surveillance technology. Under the Wassenaar Arrangement, cyberweapons and surveillance technology should be listed as “very sensitive items” and subject to additional control because exports can lead to derivative viruses, which multiply the harm of the original export. Finally, the existing framework is unclear in its differentiation between cyberweapons subject to strict control as weapons and those subject to less control as dual-use items. International control lists should include an addendum to the general rule assigning particular types of software to consistently implement each category across jurisdictions

    Organophosphate hydrolase is a lipoprotein and interacts with pi-specific transport system to facilitate growth of <i>brevundimonas diminuta</i> using op insecticide as source of phosphate

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    Organophosphate Hydrolase (OPH), encoded by the organophosphate degradation (opd) island, hydrolyzes the triester bond found in a variety of organophosphate insecticides and nerve agents. OPH is targeted to the inner membrane of Brevundimonas diminuta in a pre-folded conformation by the Twin arginine transport (Tat) pathway. The OPH signal peptide contains an invariant cysteine residue at the junction of the signal peptidase (Spase) cleavage site along with a well conserved lipobox motif. Treatment of cells producing native OPH with the signal peptidase II inhibitor globomycin resulted in accumulation of most of the pre-OPH in the cytoplasm with negligible processed OPH detected in the membrane. Substitution of the conserved lipobox cysteine to serine resulted in release of OPH into the periplasm, confirming that OPH is a lipoprotein. Analysis of purified OPH revealed that it was modified with the fatty acids palmitate and stearate. Membrane-bound OPH was shown to interact with the outer membrane efflux protein TolC and with PstS, the periplasmic component of the ABC transporter complex (PstSACB) involved in phosphate transport. Interaction of OPH with PstS appears to facilitate transport of Pigenerated from organophosphates due to the combined action of OPH and periplasmically located phosphatases. Consistent with this model, opd null mutants of B. diminuta failed to grow using the organophosphate insecticide methyl parathion as sole source of phosphate

    Single-Step Production of a Recyclable Nanobiocatalyst for Organophosphate Pesticides Biodegradation Using Functionalized Bacterial Magnetosomes

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    Enzymes are versatile catalysts in laboratories and on an industrial scale; improving their immobilization would be beneficial to broadening their applicability and ensuring their (re)use. Lipid-coated nano-magnets produced by magnetotactic bacteria are suitable for a universally applicable single-step method of enzyme immobilization. By genetically functionalizing the membrane surrounding these magnetite particles with a phosphohydrolase, we engineered an easy-to-purify, robust and recyclable biocatalyst to degrade ethyl-paraoxon, a commonly used pesticide. For this, we genetically fused the opd gene from Flavobacterium sp. ATCC 27551 encoding a paraoxonase to mamC, an abundant protein of the magnetosome membrane in Magnetospirillum magneticum AMB-1. The MamC protein acts as an anchor for the paraoxonase to the magnetosome surface, thus producing magnetic nanoparticles displaying phosphohydrolase activity. Magnetosomes functionalized with Opd were easily recovered from genetically modified AMB-1 cells: after cellular disruption with a French press, the magnetic nanoparticles are purified using a commercially available magnetic separation system. The catalytic properties of the immobilized Opd were measured on ethyl-paraoxon hydrolysis: they are comparable with the purified enzyme, with Km (and kcat) values of 58 ”M (and 178 s−1) and 43 ”M (and 314 s−1) for the immobilized and purified enzyme respectively. The Opd, a metalloenzyme requiring a zinc cofactor, is thus properly matured in AMB-1. The recycling of the functionalized magnetosomes was investigated and their catalytic activity proved to be stable over repeated use for pesticide degradation. In this study, we demonstrate the easy production of functionalized magnetic nanoparticles with suitably genetically modified magnetotactic bacteria that are efficient as a reusable nanobiocatalyst for pesticides bioremediation in contaminated effluents

    Sustainable Sources of Biomass for Bioremediation of Heavy Metals in Waste Water Derived from Coal-Fired Power Generation

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    Biosorption of heavy metals using dried algal biomass has been extensively described but rarely implemented. We contend this is because available algal biomass is a valuable product with a ready market. Therefore, we considered an alternative and practical approach to algal bioremediation in which algae were cultured directly in the waste water stream. We cultured three species of algae with and without nutrient addition in water that was contaminated with heavy metals from an Ash Dam associated with coal-fired power generation and tested metal uptake and bioremediation potential. All species achieved high concentrations of heavy metals (to 8% dry mass). Two key elements, V and As, reached concentrations in the biomass of 1543 mg.kg−1 DW and 137 mg.kg−1 DW. Growth rates were reduced by more than half in neat Ash Dam water than when nutrients were supplied in excess. Growth rate and bioconcentration were positively correlated for most elements, but some elements (e.g. Cd, Zn) were concentrated more when growth rates were lower, indicating the potential to tailor bioremediation depending on the pollutant. The cosmopolitan nature of the macroalgae studied, and their ability to grow and concentrate a suite of heavy metals from industrial wastes, highlights a clear benefit in the practical application of waste water bioremediation

    An overview of the utilisation of microalgae biomass derived from nutrient recycling of wet market wastewater and slaughterhouse wastewater

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    Microalgae have high nutritional values for aquatic organisms compared to ïŹsh meal, because microalgae cells are rich in proteins, lipids, and carbohydrates. However, the high cost for the commercial production of microalgae biomass using fresh water or artiïŹcial media limits its use as ïŹsh feed. Few studies have investigated the potential of wet market wastewater and slaughterhouse wastewater for the production of microalgae biomass. Hence, this study aims to highlight the potential of these types of wastewater as an alternative superior medium for microalgae biomass as they contain high levels of nutrients required for microalgae growth. This paper focuses on the beneïŹts of microalgae biomass produced during the phycore-mediation of wet market wastewater and slaughterhouse wastewater as ïŹsh feed. The extraction techniques for lipids and proteins as well as the studies conducted on the use of microalgae biomass as ïŹsh feed were reviewed. The results showed that microalgae biomass can be used as ïŹsh feed due to feed utilisation efïŹciency, physiological activity, increased resistance for several diseases, improved stress response, and improved protein retention

    The evolution of new enzyme function: lessons from xenobiotic metabolizing bacteria versus insecticide-resistant insects

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    Here, we compare the evolutionary routes by which bacteria and insects have evolved enzymatic processes for the degradation of four classes of synthetic chemical insecticide. For insects, the selective advantage of such degradative activities is survival on exposure to the insecticide, whereas for the bacteria the advantage is simply a matter of access to additional sources of nutrients. Nevertheless, bacteria have evolved highly efficient enzymes from a wide variety of enzyme families, whereas insects have relied upon generalist esterase-, cytochrome P450- and glutathione-S-transferase-dependent detoxification systems. Moreover, the mutant insect enzymes are less efficient kinetically and less diverged in sequence from their putative ancestors than their bacterial counterparts. This presumably reflects several advantages that bacteria have over insects in the acquisition of new enzymatic functions, such as a broad biochemical repertoire from which new functions can be evolved, large population sizes, high effective mutation rates, very short generation times and access to genetic diversity through horizontal gene transfer. Both the insect and bacterial systems support recent theory proposing that new biochemical functions often evolve from ‘promiscuous’ activities in existing enzymes, with subsequent mutations then enhancing those activities. Study of the insect enzymes will help in resistance management, while the bacterial enzymes are potential bioremediants of insecticide residues in a range of contaminated environments
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