Gas fermentation by acetogens of the genus Clostridium is an attractive technology since it affords the production of biochemicals and biofuels from industrial waste gases while contributing to ...mitigate the carbon cycle alterations. The acetogenic model organisms C. ljungdahlii and C. autoethanogenum have already been used in large scale industrial fermentations. Among the natural products, ethanol production has already attained industrial scale. However, some acetogens are also natural producers of 2,3-butanediol (2,3-BDO), a platform chemical of relevant industrial interest. Here, we have developed a lab-scale screening campaign with the aim of enhancing 2,3-BDO production. Our study generated comparable data on growth and 2,3-BDO production of several batch gas fermentations using C. ljungdahlii and C. autoethanogenum grown on different gas substrates of primary applicative interest (CO2 · H2, CO · CO2, syngas) and on different media featuring different compositions as regards trace metals, mineral elements and vitamins. CO · CO2 fermentation was found to be preferable for the production of 2,3-BDO, and a fair comparison of the strains cultivated in comparable conditions revealed that C. ljungdahlii produced 3.43-fold higher titer of 2,3-BDO compared to C. autoethanogenum. Screening of different medium compositions revealed that mineral elements, Zinc and Iron exert a major positive influence on 2,3-BDO titer and productivity. Moreover, the CO2 influence on CO fermentation was explored by characterizing C. ljungdahlii response with respect to different gas ratios in the CO · CO2 gas mixtures. The screening strategies undertaken in this study led to the production of 2.03 ± 0.05 g/L of 2,3-BDO, which is unprecedented in serum bottle experiments.
This paper uses new data and new econometric techniques to investigate the impact of international financial integration on economic growth and also to assess whether this relationship depends on the ...level of economic development, financial development, legal system development, government corruption, and macroeconomic policies. Using a wide array of measures of international financial integration for 57 countries and an assortment of statistical methodologies, we are unable to reject the null hypothesis that international financial integration does not accelerate economic growth even when controlling for particular economic, financial, institutional, and policy characteristics.
Does gross or net debt matter for long-term sovereign spreads in emerging markets? The topic is important for undestanding the borrowing cost implications of public assetliability management ...decisions (e.g. using assets to lower debt). We investigate this question using data on emerging market economies (EMEs) over the period 1998-2014. We find that both gross debt and assets have a significant impact on long-term sovereign bond spreads in emerging markets, with effects roughly offsetting each other (coefficients of opposite sign and similar magnitude). Hence, net debt seems more appropriate than gross debt when evaluating the impact of indebtedness on spreads. The empirical results suggest that an increase in net debt by 10 percentage points of GDP implies an increase in the spread by 100-120 basis points, and the effect is larger during periods of domestic distress. The key results from this empirical study are quite robust to alternative specifications and subgroups of EMEs.
We present moderate (∼5″) and high angular resolution (∼1″) observations of 12CO (J = 2 − 1) emission toward the nearby interacting galaxy NGC 3627 taken with the Submillimeter Array (SMA). These SMA ...mosaic maps of NGC 3627 reveal a prominent nuclear peak, inter-arm regions, and diffuse, extended emission in the spiral arms. A velocity gradient of ∼400-450 km s−1 is seen across the entire galaxy with velocity dispersions ranging from 80 km s−1 toward the nuclear region to 15 km s−1 in the spiral arms. We also detect unresolved 13CO (J = 2 − 1) line emission toward the nuclear region, southern bar end, and in a relatively isolated clump in the southern portion of the galaxy, while no C18O(J = 2 − 1) line emission is detected at a 3 rms noise level of 42 mJy beam−1 per 20 km s−1 channel. Using RADEX modeling with a large velocity gradient approximation, we derive kinetic temperatures ranging from ∼5 to 10 K (in the spiral arms) to ∼25 K (at the center) and H2 number densities from ∼400 to 1000 cm−3 (in the spiral arms) to ∼12,500 cm−3 (at the center). From this density modeling, we find a total H2 mass of 9.6 × 109 M , which is ∼50% higher than previous estimates made using a constant H2-CO conversion factor, but is largely dependent on the assumed vertical distribution of the CO gas. With the exception of the nuclear region, we also identify a tentative correlation between star formation efficiency and kinetic temperature. We derive a galactic rotation curve, finding a peak velocity of ∼207 km s−1 and estimate a total dynamical mass of 4.94 0.70 × 1010 M at a galactocentric radius of ∼6.2 kpc (121″).
X-linked chronic granulomatous disease is a rare disease caused by mutations in the CYBB gene. While more extensive knowledge is available on genetics, pathogenesis, and possible therapeutic options, ...mitochondrial activity and its implications on patient monitoring are still not well-characterized. We have developed a novel protocol to study mitochondrial activity on whole blood of XCGD patients before and after transplantation, as well as on XCGD carriers. Here we present results of these analyses and of the restoration of mitochondrial activity in hyperinflamed X-linked Chronic Granulomatous Disease after hematopoietic stem cell transplantation. Moreover, we show a strong direct correlation between mitochondrial activity, chimerism, and DHR monitored before and after transplantation and in XCGD carriers. In conclusion, based on these findings, we suggest testing this new ready-to-use marker to better characterize patients before and after treatment and to investigate disease expression in carriers.
We present L′-band Keck/NIRC2 imaging and H-band Subaru/AO188+HiCIAO polarimetric observations of the CQ Tau disk with a new spiral arm. Apart from the spiral feature, our observations could not ...detect any companion candidates. We traced the spiral feature from the r2-scaled High-Contrast Coronographic Imager for Adaptive Optics (HiCIAO) polarimetric intensity image and the fitted result is used for forward modeling to reproduce the ADI-reduced NIRC2 image. We estimated the original surface brightness after throughput correction in the L′ band to be ∼126 mJy arcsec−2 at most. We suggest that the grain temperature of the spiral may be heated up to ∼200 K in order to explain both of the H- and L′-band results. The H-band emission at the location of the spiral originates from the scattering from the disk surface while both scattering and thermal emission may contribute to the L′-band emission. If the central star is only the light source of scattered light, the spiral emission at the L′ band should be thermal emission. If an inner disk also acts as the light source, the scattered light and the thermal emission may equally contribute to the L′-band spiral structure.
Gas fermentation provides a promising platform to turn low-cost and readily available single-carbon waste gases into commodity chemicals, such as 2,3-butanediol. Clostridium autoethanogenum is ...usually used as a robust and flexible chassis for gas fermentation. Here, we leveraged constraint-based stoichiometric modeling and kinetic ensemble modeling of the
metabolic network to provide a systematic
analysis of metabolic engineering interventions for 2,3-butanediol overproduction and low carbon substrate loss in dissipated CO
. Our analysis allowed us to identify and to assess comparatively the expected performances for a wide range of single, double, and triple interventions. Our analysis managed to individuate bottleneck reactions in relevant metabolic pathways when suggesting intervening strategies. Besides recapitulating intuitive and/or previously attempted genetic modifications, our analysis neatly outlined that interventions-at least partially-impinging on by-products branching from acetyl coenzyme A (acetyl-CoA) and pyruvate (acetate, ethanol, amino acids) offer valuable alternatives to the interventions focusing directly on the specific branch from pyruvate to 2,3-butanediol.
Envisioning value chains inspired by environmental sustainability and circularity in economic models is essential to counteract the alterations in the global natural carbon cycle induced by humans. Recycling carbon-based waste gas streams into chemicals by devising gas fermentation bioprocesses mediated by acetogens of the genus
is one component of the solution. Carbon monoxide originates from multiple biogenic and abiogenic sources and bears a significant environmental impact. This study aims at identifying metabolic engineering interventions for increasing 2,3-butanediol production and avoiding carbon loss in CO
dissipation via
fermenting a substrate comprising CO and H
. 2,3-Butanediol is a valuable biochemical by-product since, due to its versatility, can be transformed quite easily into chemical compounds such as butadiene, diacetyl, acetoin, and methyl ethyl ketone. These compounds are usable as building blocks to manufacture a vast range of industrially produced chemicals.
Traditionally viewed as poorly plastic, neutrophils are now recognized as functionally diverse; however, the extent and determinants of neutrophil heterogeneity in humans remain unclear. We performed ...a comprehensive immunophenotypic and transcriptome analysis, at a bulk and single-cell level, of neutrophils from healthy donors and patients undergoing stress myelopoiesis upon exposure to growth factors, transplantation of hematopoietic stem cells (HSC-T), development of pancreatic cancer and viral infection. We uncover an extreme diversity of human neutrophils in vivo, reflecting the rates of cell mobilization, differentiation and exposure to environmental signals. Integrated control of developmental and inducible transcriptional programs linked flexible granulopoietic outputs with elicitation of stimulus-specific functional responses. In this context, we detected an acute interferon (IFN) response in the blood of patients receiving HSC-T that was mirrored by marked upregulation of IFN-stimulated genes in neutrophils but not in monocytes. Systematic characterization of human neutrophil plasticity may uncover clinically relevant biomarkers and support the development of diagnostic and therapeutic tools.
Carbon dioxide (CO2) stands out as sustainable feedstock for developing a circular carbon economy whose energy supply could be obtained by boosting the production of clean hydrogen from renewable ...electricity. H2‐dependent CO2 gas fermentation using acetogenic microorganisms offers a viable solution of increasingly demonstrated value. While gas fermentation advances to achieve commercial process scalability, which is currently limited to a few products such as acetate and ethanol, it is worth taking the best of the current state‐of‐the‐art technology by its integration within innovative bioconversion schemes. This review presents multiple scenarios where gas fermentation by acetogens integrate into double‐stage biotechnological production processes that use CO2 as sole carbon feedstock and H2 as energy carrier for products' synthesis. In the integration schemes here reviewed, the first stage can be biotic or abiotic while the second stage is biotic. When the first stage is biotic, acetogens act as a biological platform to generate chemical intermediates such as acetate, formate and ethanol that become substrates for a second fermentation stage. This approach holds the potential to enhance process titre/rate/yield metrics and products' spectrum. Alternatively, when the first stage is abiotic, the integrated two‐stage scheme foresees, in the first stage, the catalytic transformation of CO2 into C1 products that, in the second stage, can be metabolized by acetogens. This latter scheme leverages the metabolic flexibility of acetogens in efficient utilization of the products of CO2 abiotic hydrogenation, namely formate and methanol, to synthesize multicarbon compounds but also to act as flexible catalysts for hydrogen storage or production.
Carbon dioxide recycling is a compelling need and microbial carbon dioxide fixation in value‐added compounds is a valuable opportunity. Fermentation of CO2 gas streams using acetogenic bacteria is consolidating as a key biotechnology to move toward a cyclic carbon economy. Throughout the review, we pinpointed an ample range of products that are technically attainable by reframing a CO2‐based gas fermentation process within a two‐stage context with the aim of highlighting some avenues available for fruitful exploitation of the current technology.
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