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This paper is dedicated to studying and modeling the interdependence between the oil returns and exchange-rate movements of oil-exporting and oil-importing countries. Globally, twelve countries/regions are investigated, representing more than 60% and 67% of all oil exports and imports. The sample period encompasses economic and natural events like the Great Recession period (2007–2009) and the COVID-19 pandemic. We use the dynamic conditional correlation mixed-data sampling (DCC-MIDAS) model, with the aim of investigating the interdependencies expressed by the long-run correlation, which is a smoother (but always daily observed) version of the (daily) time-varying correlation. Focusing on the advent of the COVID-19 pandemic in 2020, the long-run correlations of the oil-exporting countries (Saudia Arabia, Russia, Iraq, Canada, United States, United Arab Emirates, and Nigeria) and (lagged) WTI crude oil returns strongly increase. For a subset of these countries (that is, Saudia Arabia, Iraq, United States, United Arab Emirates, and Nigeria), the (lagged) correlations turn out to be positive, while for Canada and Russia they remain negative as before the advent of the pandemic. In addition, the oil-importing countries and regions under investigation (Europe, China, India, Japan, and South Korea) experience a similar pattern: before the COVID-19 pandemic, the (lagged) correlations were negative for China, India, and South Korea. After the COVID-19 pandemic, the correlations of these latter countries increased.

Two novel datasets are used to estimate the effect of product standards on firms’ export decisions. The first covers all exporting firms in 42 developing countries. The second covers pesticide standards for 243 agricultural and food products in 80 importing countries over 2006–2012. The analysis shows that product standards affect significantly foreign market access. An increase in the stringency of standards in the destination country, relative to the exporting country, lowers firms’ probability of exporting, deters exporters from entering new markets, and fosters exit from existing markets. Smaller exporters are more affected in their market entry and exit decisions by the relative stringency of destination standards than larger exporters. Networks of other exporters from the same country can help overcome the negative effects of the relative stringency of destination standards on exporter entry and exit.

Glyphosate is the most widely used herbicide in world agriculture and for general vegetation control in a wide range of situations. Global and often intensive glyphosate selection of very large weedy plant populations has resulted in widespread glyphosate resistance evolution in populations of many weed species. Here, working with a glyphosate-resistant (GR) Echinochloa colona population that evolved in a Western Australia agricultural field, we identified an ATP-binding cassette (ABC) transporter (EcABCC8) that is consistently up-regulated in GR plants. When expressed in transgenic rice, this EcABCC8 transporter endowed glyphosate resistance. Equally, rice, maize, and soybean overexpressing the EcABCC8 ortholog genes were made resistant to glyphosate. Conversely, CRISPR/Cas9-mediated knockout of the EcABCC8 ortholog gene OsABCC8 increased rice susceptibility to glyphosate. Subcellular localization analysis and quantification of glyphosate cellular levels in treated ABCC8 transgenic rice plants and isolated leaf protoplasts as well as structural modeling support that EcABCC8 is likely a plasma membrane–localized transporter extruding cytoplasmic glyphosate to the apoplast, lowering the cellular glyphosate level. This is a report of a membrane transporter effluxing glyphosate in a GR plant species, and its function is likely conserved in crop plant species.

Arbuscular mycorrhizal fungi form symbiotic associations with most land plants and deliver mineral nutrients, in particular phosphate, to the host. Therefore, understanding the mechanisms of phosphate acquisition and delivery in the fungi is critical for full appreciation of the mutualism in this association. Here, we provide updates on physical, chemical, and biological strategies of the fungi for phosphate acquisition, including interactions with phosphate-solubilizing bacteria, and those on the regulatory mechanisms of phosphate homeostasis based on resurveys of published genome sequences and a transcriptome with reference to the latest findings in a model fungus. For the mechanisms underlying phosphate translocation and export to the host, which are major research frontiers in this field, not only recent advances but also testable hypotheses are proposed. Lastly, we briefly discuss applicability of the latest tools to gene silencing in the fungi, which will be breakthrough techniques for comprehensive understanding of the molecular basis of fungal phosphate metabolism.

Enterobacteriaceae produce antimicrobial peptides for survival under nutrient starvation. Microcin J25 (MccJ25) is an antimicrobial peptide with a unique lasso topology. It is secreted by the ATP-binding cassette (ABC) exporter McjD, which ensures self-immunity of the producing strain through efficient export of the toxic mature peptide from the cell. Here we have determined the crystal structure of McjD from Escherichia coli at 2.7-Å resolution, which is to the authors’ knowledge the first structure of an antibacterial peptide ABC transporter. Our functional and biochemical analyses demonstrate McjD-dependent immunity to MccJ25 through efflux of the peptide. McjD can directly bind MccJ25 and displays a basal ATPase activity that is stimulated by MccJ25 in both detergent solution and proteoliposomes. McjD adopts a new conformation, termed nucleotide-bound outward occluded. The new conformation defines a clear cavity; mutagenesis and ligand binding studies of the cavity have identified Phe86, Asn134, and Asn302 as important for recognition of MccJ25. Comparisons with the inward-open MsbA and outward-open Sav1866 structures show that McjD has structural similarities with both states without the intertwining of transmembrane (TM) helices. The occluded state is formed by rotation of TMs 1 and 2 toward the equivalent TMs of the opposite monomer, unlike Sav1866 where they intertwine with TMs 3–6 of the opposite monomer. Cysteine cross-linking studies on the McjD dimer in inside-out membrane vesicles of E. coli confirmed the presence of the occluded state. We therefore propose that the outward-occluded state represents a transition intermediate between the outward-open and inward-open conformation of ABC exporters.

d-amino acids have recently been found to be present in the extracellular milieu at millimolar levels and are therefore assumed to play a physiological function. However, the pathway (or potential pathways) by which these d-amino acids are secreted remains unknown. Recently, Escherichia coli has been found to possess one or more energy-dependent d-alanine export systems. To gain insight into these systems, we developed a novel screening system in which cells expressing a putative d-alanine exporter could support the growth of d-alanine auxotrophs in the presence of l-alanyl–l-alanine. In the initial screening, five d-alanine exporter candidates, AlaE, YmcD, YciC, YraM, and YidH, were identified. Transport assays of radiolabeled d-alanine in cells expressing these candidates indicated that YciC and AlaE resulted in lower intracellular levels of d-alanine. Further detailed transport assays of AlaE in intact cells showed that it exports d-alanine in an expression-dependent manner. In addition, the growth constraints on cells in the presence of 90 mM d-alanine were mitigated by the overexpression of AlaE, implying that AlaE could export free d-alanine in addition to l-alanine under conditions in which intracellular d/l-alanine levels are raised. This study also shows, for the first time, that YciC could function as a d-alanine exporter in intact cells.

Purpose>This study aims to develop a new internationalisation model to describe the exporting and non-exporting behaviours of small and medium sized enterprises (SMEs) and then applying it to a sample of UK SMEs. The conceptual model consists of four forces leading to a successful business.Design/methodology/approach>The sample is a stratified one taken from KOMPASS directory and focussing on the Greater Manchester area. In total, 250 firms were chosen to be the population of this survey. In total, 110 surveys were received by email i.e. 24 non-exporters and 86 exporters that were fully completed.Findings>The four forces of the model include the non-exporting activity, the activity before and after the first export order, differences and similarities between non-exporters and exporters and the regular exporting activity. This model’s findings demonstrate important empirical determinants related to four forces, which, in turn, shape the successful exporting activity.Originality/value>The empirical evidence from the study suggests that the major differences between non-exporters and exporters, which include the differences in management perceptions towards exporting, and the differences and similarities of firm and management characteristics, explain only to some degree what constitutes successful exporting behaviour. The model is considered useful for smaller businesses located in the UK. The study highlights the importance of firms before and after the first export order, which provides insights for managers of firms about going through with the first export order rather than withdrawing from this effort. The study reveals the motivations for exporting, the timing, the modes through which firms export, firms’ management characteristics and attitudinal differences between exporters and non-exporters, which are essential for practitioners.

PurposeThis study aims to compare the level of organizational capabilities of the exporter and non-exporter Iranian knowledge-based firms in the sector of chemical technology.Design/methodology/approachBy combining 18 different indicators, a framework is designed to demonstrate organizational capabilities. The technological, manufacturing, R&D, marketing, organizing and financial capabilities of 732 Iranian knowledge-based firms in the sector of chemical technology (90 exporters and 642 non-exporter firms) are identified between 2015 and 2020. The analysis is based on the Chi-square test and logistic and probit regression.FindingsThe results indicate that technological capability, unlike the other five capabilities, is higher in non-exporter firms, and the level of marketing capability is greater in exporter firms, with the highest difference between the two groups.Originality/valueThe research suggests that knowledge-based firms should be evaluated based on export history; there should be some specialized export facilitating packages for both exporter and non-exporter firms; and some baskets from products with related and specialized fields of application should be formed to facilitate international marketing. The results can be a basis for managers and policymakers to improve the firm’s capabilities and competitiveness at the international level.

The L-valine production strain of Escherichia coli was constructed by rational metabolic engineering and stepwise improvement based on transcriptome analysis and gene knockout simulation of the in silico genome-scale metabolic network. Feedback inhibition of acetohydroxy acid synthase isoenzyme III by L-valine was removed by site-directed mutagenesis, and the native promoter containing the transcriptional attenuator leader regions of the ilvGMEDA and ilvBN operon was replaced with the tac promoter. The ilvA, leuA, and panB genes were deleted to make more precursors available for L-valine biosynthesis. This engineered Val strain harboring a plasmid overexpressing the ilvBN genes produced 1.31 g/liter L-valine. Comparative transcriptome profiling was performed during batch fermentation of the engineered and control strains. Among the down-regulated genes, the lrp and ygaZH genes, which encode a global regulator Lrp and L-valine exporter, respectively, were overexpressed. Amplification of the lrp, ygaZH, and lrp-ygaZH genes led to the enhanced production of L-valine by 21.6%, 47.1%, and 113%, respectively. Further improvement was achieved by using in silico gene knockout simulation, which identified the aceF, mdh, and pfkA genes as knockout targets. The VAMF strain (Val ΔaceF Δmdh ΔpfkA) overexpressing the ilvBN, ilvCED, ygaZH, and lrp genes was able to produce 7.55 g/liter L-valine from 20 g/liter glucose in batch culture, resulting in a high yield of 0.378 g of L-valine per gram of glucose. These results suggest that an industrially competitive strain can be efficiently developed by metabolic engineering based on combined rational modification, transcriptome profiling, and systems-level in silico analysis.

This study aims to examine the relationship between innovation performance, entrepreneurship orientation, and competitiveness in export companies. The sample comprises 170 employees from export companies. Confirmatory Factor Analysis was used for reliability and validity analysis was performed. The research findings showed that entrepreneurship orientation affects competitiveness significantly and positively. Also, competitiveness affects by innovation performance. The correlations between the variables were found statistically significant and mediator effect were analyzed by Baron and Kenney method and confirmed by Sobel test. Innovation performance has mediator effect on the relationship between entrepreneurship orientation and competitiveness.