167 research outputs found

    Exchange Rate and World Currency

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    This paper explores the derivation of exchange rate and the way of world currency issuing, and some findings are captured as: the world’s currency demand is equal to the global export increment, and that every nation’s world currency needs should equal to their own export increment. Currently, there are issues with the existing world currency system, which many countries or regions call for change. Because all the existing proposals in the field have their constraints, so this paper suggests that the world central bank issuing a global currency with which each country would take its own share and maintain that the world currency supply to be equal to the global export increments. This will be more sustainable for international business and this theory of world currency does have advantage over existing systems

    The Whole Economy Approach of the Input-Output Model

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    In macroeconomy research that uses technological table, most studies have only considered a special aspect. This paper develops an input-output model that extends to the whole economy by adding finance into transaction table. This forms a integrated capital flow cycling system for whole economy. Economic growth is used to reflect economic dynamic characteristics. Whole economy is divided into five subsystems. On the basis of subsystem's balance sheet, we set up the simultaneous equation of whole economy. As part of the disposal income, the new loan of the subsystems are affected by money supply badly and the income ratio is not stable. In this paper, expenditure ratio of subsystems is used to solve the simultaneous equation. The subsystem's balance sheets and the simultaneous equation can be applied to study fundamental economic issues effectively

    The Whole Economy Approach of the Input-Output Model

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    In macroeconomy research that uses technological table, most studies have only considered a special aspect. This paper develops an input-output model that extends to the whole economy by adding finance into transaction table. This forms a integrated capital flow cycling system for whole economy. Economic growth is used to reflect economic dynamic characteristics. Whole economy is divided into five subsystems. On the basis of subsystem's balance sheet, we set up the simultaneous equation of whole economy. As part of the disposal income, the new loan of the subsystems are affected by money supply badly and the income ratio is not stable. In this paper, expenditure ratio of subsystems is used to solve the simultaneous equation. The subsystem's balance sheets and the simultaneous equation can be applied to study fundamental economic issues effectively

    LeTetR Positively Regulates 3-Hydroxylation of the Antifungal HSAF and Its Analogs in \u3ci\u3eLysobacter enzymogenes\u3c/i\u3e OH11

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    The biocontrol agent Lysobacter enzymogenes OH11 produces several structurally distinct antibiotic compounds, including the antifungal HSAF (Heat Stable Antifungal Factor) and alteramides, along with their 3-dehydroxyl precursors (3-deOH). We previously showed that the 3-hydroxylation is the final step of the biosynthesis and is also a key structural moiety for the antifungal activity. However, the procedure through which OH11 regulates the 3-hydroxylation is still not clear. In OH11, the gene orf3232 was predicted to encode a TetR regulator (LeTetR) with unknown function. Here, we deleted orf3232 and found that the LeTetR mutant produced very little HSAF and alteramides, while the 3-deOH compounds were not significantly affected. The production of HSAF and alteramides was restored in orf3232-complemented mutant. qRT-PCR showed that the deletion of orf3232 impaired the transcription of a putative fatty acid hydroxylase gene, orf2195, but did not directly affect the expression of the HSAF biosynthetic gene cluster (hsaf ). When an enzyme extract from E. coli expressing the fatty acid hydroxylase gene, hsaf -orf7, was added to the LeTetR mutant, the production of HSAF and alteramides increased by 13–14 fold. This study revealed a rare function of the TetR family regulator, which positively controls the final step of the antifungal biosynthesis and thus controls the antifungal activity of the biocontrol agent

    A TonB-dependent receptor regulates antifungal HSAF biosynthesis in \u3ci\u3eLysobacter\u3c/i\u3e

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    Lysobacter species are Gram-negative bacteria that are emerging as new sources of antibiotics, including HSAF (Heat Stable Antifungal Factor), which was identified from L. enzymogenes with a new mode of action. LesR, a LuxR solo, was recently shown to regulate the HSAF biosynthesis via an unidentified mechanism in L. enzymogenes OH11. Here, we used a comparative proteomic approach to identify the LesR targets and found that LesR influenced the expression of 33 proteins belonging to 10 functional groups, with 9 proteins belonging to the TBDR (TonB-Dependent Receptor) family. The fundamental role of bacterial TBDR in nutrient uptake motivates us to explore their potential regulation on HSAF biosynthesis which is also modulated by nutrient condition. Six out of 9 TBDR coding genes were individually in-frame deleted. Phenotypic and gene-expression assays showed that TBDR7, whose level was lower in a strain overexpressing lesR, was involved in regulating HSAF yield. TBDR7 was not involved in the growth, but played a vital role in transcribing the key HSAF biosynthetic gene. Taken together, the current lesR-based proteomic study provides the first report that TBDR7 plays a key role in regulating antibiotic (HSAF) biosynthesis, a function which has never been found for TBDRs in bacteria. Includes Supplementary materials

    A Scalable Arrangement Method for Aperiodic Array Antennas to Reduce Peak Sidelobe Level

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    Peak sidelobe level reduction (PSLR) is crucial in the application of large-scale array antenna, which directly determines the radiation performance of array antenna. We study the PSLR of subarray level aperiodic arrays and propose three array structures: dislocated subarrays with uniform elements (DSUE), uniform subarrays with random elements (USRE), dislocated subarrays with random elements (DSRE). To optimize the dislocation position of subarrays and random position of elements, the improved Bat algorithm (IBA) is applied. To draw the comparison of PSLR effect among these three array structures, we take three size of array antennas from small to large as examples to simulate and calculate the redundancy and peak sidelobe level (PSLL) of them. The results show that DSRE is the optimal array structure by analyzing the dislocation distance of subarray, scanning angle and applicable frequency. The proposed design method is a universal and scalable method, which is of great application value to the design of large-scale aperiodic array antenna

    Novel Salicylic Acid Analogs Induce a Potent Defense Response in Arabidopsis

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    The master regulator of salicylic acid (SA)-mediated plant defense, NPR1 (NONEXPRESSER OF PR GENES 1) and its paralogs NPR3 and NPR4, act as SA receptors. After the perception of a pathogen, plant cells produce SA in the chloroplast. In the presence of SA, NPR1 protein is reduced from oligomers to monomers, and translocated into the nucleus. There, NPR1 binds to TGA, TCP, and WRKY transcription factors to induce expression of plant defense genes. A list of compounds structurally similar to SA was generated using ChemMine Tools and its Clustering Toolbox. Several of these analogs can induce SA-mediated defense and inhibit growth of Pseudomonas syringae in Arabidopsis. These analogs, when sprayed on Arabidopsis, can induce the accumulation of the master regulator of plant defense NPR1. In a yeast two-hybrid system, these analogs can strengthen the interactions among NPR proteins. We demonstrated that these analogs can induce the expression of the defense marker gene PR1. Furthermore, we hypothesized that these SA analogs could be potent tools against the citrus greening pathogen Candidatus liberibacter spp. In fact, our results suggest that the SA analogs we tested using Arabidopsis may also be effective for inducing a defense response in citrus. Several SA analogs consistently strengthened the interactions between citrus NPR1 and NPR3 proteins in a yeast two-hybrid system. In future assays, we plan to test whether these analogs avoid degradation by SA hydroxylases from plant pathogens. In future assays, we plan to test whether these analogs avoid degradation by SA hydroxylases from plant pathogens

    Identification and Characterization of the Anti-Methicillin-Resistant \u3ci\u3eStaphylococcus aureus\u3c/i\u3e WAP-8294A2 Biosynthetic Gene Cluster from \u3ci\u3eLysobacter enzymogenes\u3c/i\u3e OH11

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    Lysobactor enzymogenes strain OH11 is an emerging biological control agent of fungal and bacterial diseases. We recently completed its genome sequence and found it contains a large number of gene clusters putatively responsible for the biosynthesis of nonribosomal peptides and polyketides, including the previously identified antifungal dihydromaltophilin (HSAF). One of the gene clusters contains two huge open reading frames, together encoding 12 modules of nonribosomal peptide synthetases (NRPS). Gene disruption of one of the NRPS led to the disappearance of a metabolite produced in the wild type and the elimination of its antibacterial activity. The metabolite and antibacterial activity were also affected by the disruption of some of the flanking genes. We subsequently isolated this metabolite and subjected it to spectroscopic analysis. The mass spectrometry and nuclear magnetic resonance data showed that its chemical structure is identical to WAP-8294A2, a cyclic lipodepsipeptide with potent antimethicillin-resistant Staphylococcus aureus (MRSA) activity and currently in phase I/II clinical trials. The WAP- 8294A2 biosynthetic genes had not been described previously. So far, the Gram-positive Streptomyces have been the primary source of anti-infectives. Lysobacter are Gram-negative soil/water bacteria that are genetically amendable and have not been well exploited. The WAP-8294A2 synthetase represents one of the largest NRPS complexes, consisting of 45 functional domains. The identification of these genes sets the foundation for the study of the WAP-8294A2 biosynthetic mechanism and opens the door for producing new anti-MRSA antibiotics through biosynthetic engineering in this new source of Lysobacter
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