The familiar buzz of flying mosquitoes is an important mating signal, with the fundamental frequency of the female's flight tone signaling her presence. In the yellow fever and dengue vector Aedes ...aegypti, both sexes interact acoustically by shifting their flight tones to match, resulting in a courtship duet. Matching is made not at the fundamental frequency of 400 hertz (female) or 600 hertz (male) but at a shared harmonic of 1200 hertz, which exceeds the previously known upper limit of hearing in mosquitoes. Physiological recordings from Johnston's organ (the mosquito's "ear") reveal sensitivity up to 2000 hertz, consistent with our observed courtship behavior. These findings revise widely accepted limits of acoustic behavior in mosquitoes.
Aspergillus niger is a ubiquitous filamentous fungus widely employed as a cell factory thanks to its abilities to produce a wide range of organic acids and enzymes. Its genome was one of the first ...Aspergillus genomes to be sequenced in 2007, due to its economic importance and its role as model organism to study fungal fermentation. Nowadays, the genome sequences of more than 20 A. niger strains are available. These, however, do not include the neotype strain CBS 554.65. The genome of CBS 554.65 was sequenced with PacBio. A high-quality nuclear genome sequence consisting of 17 contigs with a N50 value of 4.07 Mbp was obtained. The assembly covered all the 8 centromeric regions of the chromosomes. In addition, a complete circular mitochondrial DNA assembly was obtained. Bioinformatic analyses revealed the presence of a MAT1-2-1 gene in this genome, contrary to the most commonly used A. niger strains, such as ATCC 1015 and CBS 513.88, which contain a MAT1-1-1 gene. A nucleotide alignment showed a different orientation of the MAT1-1 locus of ATCC 1015 compared to the MAT1-2 locus of CBS 554.65, relative to conserved genes flanking the MAT locus. Within 24 newly sequenced isolates of A. niger half of them had a MAT1-1 locus and the other half a MAT1-2 locus. The genomic organization of the MAT1-2 locus in CBS 554.65 is similar to other Aspergillus species. In contrast, the region comprising the MAT1-1 locus is flipped in all sequenced strains of A. niger. This study, besides providing a high-quality genome sequence of an important A. niger strain, suggests the occurrence of genetic flipping or switching events at the MAT1-1 locus of A. niger. These results provide new insights in the mating system of A. niger and could contribute to the investigation and potential discovery of sexuality in this species long thought to be asexual.
In order to study the nature, origin, and impact of turbulent velocity fluctuations in the ionized gas of the Orion nebula, we apply a variety of statistical techniques to observed velocity cubes. ...The cubes are derived from high resolving power (R approximately 40,000) longslit spectroscopy of optical emission lines that span a range of ionizations. From velocity channel analysis (VCA), we find that the slope of the velocity power spectrum is consistent with predictions of Kolmogorov theory between scales of 8 and 22 arcsec (0.02 to 0.05 pc). The outer scale, which is the dominant scale of density fluctuations in the nebula, approximately coincides with the autocorrelation length of the velocity fluctuations that we determine from the second-order velocity structure function. We propose that this is the principal driving scale of the turbulence, which originates in the autocorrelation length of dense cores in the Orion molecular filament. By combining analysis of the non-thermal linewidths with the systematic trends of velocity centroid versus ionization, we find that the global champagne flow and smaller scale turbulence each contribute in equal measure to the total velocity dispersion, with respective root-mean-square widths of 4-5 km s super( -1). The turbulence is subsonic and can account for only one half of the derived variance in ionized density, with the remaining variance provided by density gradients in photoevaporation flows from globules and filaments. Intercomparison with results from simulations implies that the ionized gas is confined to a thick shell and does not fill the interior of the nebula.
Transgenic Poplar Designed for Biofuels Bryant, Nathan D.; Pu, Yunqiao; Tschaplinski, Timothy J. ...
Trends in plant science,
September 2020, 2020-09-00, 20200901, 2020-09-01, Letnik:
25, Številka:
9
Journal Article
Recenzirano
Odprti dostop
Members of the genus Populus (i.e., cottonwood, hybrid poplar) represent a promising source of lignocellulosic biomass for biofuels. However, one of the major factors negatively affecting poplar’s ...efficient conversion to biofuel is the inherent recalcitrance to enzymatic saccharification due to cell wall components such as lignin. To this effect, there have been efforts to modify gene expression to reduce biomass recalcitrance by changing cell wall properties. Here, we review recent genetic modifications of poplar that led to change cell wall properties and the resulting effects on subsequent pretreatment efficacy and saccharification. Although genetic engineering’s impacts on cell wall properties are not fully predictable, recent studies have shown promising improvement in the biological conversion of transgenic poplar to biofuels.
The cell wall properties of poplar can be altered by modifying gene expression. Modifying the expression of lignin, hemicellulose, and cellulose biosynthesis genes have both been demonstrated to have an impact on poplar’s natural recalcitrance to enzymatic saccharification.Lignin is typically cited as the primary contributor to recalcitrance. However, as modifying gene expression usually results in multifaceted effects on cell wall chemistry, it is difficult to attribute improved saccharification to any single factor.As examined in this review, the effects (or interaction of effects) from genetic engineering on poplar have, in some cases, resulted in drastic improvements in saccharification efficiency.
Drawing upon investor attention and moral leadership theories, we examine the impact of President Trump’s tweets on firms’ market returns. In the first stage, we used event study methodology to ...measure market returns of public firms that were the subjects of the president’s tweets for the 30-month period starting with his election in November 2016. We found that total market returns increased by $50.03 billion at event window 0,0, $85.85 billion at window 0,1, and $145.54 billion at window 0,5. In the second stage, using linguistic textual analysis, we ran multiple regression models to further examine the degree to which tweet sentiments explain variations in market returns. Sentiments associated with authenticity and self-praise were positively associated whereas emotional tone, insight, risk, and credibility deficit were negatively associated with market returns. The results suggest that moral leadership style influences the effect of presidential tweets on stock prices.
Interactions between the host and its microbiota are of mutual benefit and promote health. Complex molecular pathways underlie this dialog, but the identity of microbe-derived molecules that mediate ...the mutualistic state remains elusive. Helicobacter hepaticus is a member of the mouse intestinal microbiota that is tolerated by the host. In the absence of an intact IL-10 signaling, H. hepaticus induces an IL-23-driven inflammatory response in the intestine. Here we investigate the interactions between H. hepaticus and host immune cells that may promote mutualism, and the microbe-derived molecule(s) involved. Our results show that H. hepaticus triggers early IL-10 induction in intestinal macrophages and produces a large soluble polysaccharide that activates a specific MSK/CREB-dependent anti-inflammatory and repair gene signature via the receptor TLR2. These data identify a host-bacterial interaction that promotes mutualistic mechanisms at the intestinal interface. Further understanding of this pathway may provide novel prevention and treatment strategies for inflammatory bowel disease.
Display omitted
•Helicobacter hepaticus (Hh) activates a specific anti-inflammatory program in macrophages•This activity is driven by an Hh polysaccharide inducing high IL-10/IL-6 ratio in BMDMs•The polysaccharide-specific response is dependent on the TLR2/MSK/CREB pathway
Host-microbiota interactions are of mutual benefit, and chronic intestinal inflammation develops when this dialog is altered. Danne et al. identified a polysaccharide produced by Helicobacter hepaticus that induces a specific anti-inflammatory and repair program in macrophages by activating the TLR2/MSK/CREB pathway. Further understanding may provide prevention and treatment strategies for IBD.
ABSTRACT We present the results of radiation-magnetohydrodynamic simulations of the formation and expansion of Hii regions and their surrounding photodissociation regions (PDRs) in turbulent, ...magnetized, molecular clouds on scales of up to 4 pc. We include the effects of ionizing and non-ionizing ultraviolet radiation and X-rays from population synthesis models of young star clusters. For all our simulations we find that the Hii region expansion reduces the disordered component of the magnetic field, imposing a large-scale order on the field around its border, with the field in the neutral gas tending to lie along the ionization front, while the field in the ionized gas tends to be perpendicular to the front. The highest pressure-compressed neutral and molecular gas is driven towards approximate equipartition between thermal, magnetic and turbulent energy densities, whereas lower pressure neutral/molecular gas bifurcates into, on the one hand, quiescent, magnetically dominated regions and, on the other hand, turbulent, demagnetized regions. The ionized gas shows approximate equipartition between thermal and turbulent energy densities, but with magnetic energy densities that are 1-3 orders of magnitude lower. A high velocity dispersion (8 km s-1) is maintained in the ionized gas throughout our simulations, despite the mean expansion velocity being significantly lower. The magnetic field does not significantly brake the large-scale Hii region expansion on the length and time-scales accessible to our simulations, but it does tend to suppress the smallest scale fragmentation and radiation-driven implosion of neutral/molecular gas that forms globules and pillars at the edge of the Hii region. However, the relative luminosity of ionizing and non-ionizing radiation has a much larger influence than the presence or absence of the magnetic field. When the star cluster radiation field is relatively soft (as in the case of a lower mass cluster, containing an earliest spectral type of B0.5), then fragmentation is less vigorous and a thick, relatively smooth PDR forms.
Civic engagement in adolescence is encouraged because it is hypothesized to promote better civic, social, and behavioral outcomes. However, few studies have examined the effects of civic engagement ...on youth development over time. In particular, the long-term association between adolescent civic engagement and development among racial minority youth who are exposed to high levels of risk factors is understudied. Using data from the Chicago Longitudinal Study (CLS;
N
= 854; 56.6 % were female; 93 % were African Americans and 7 % were Latinos), this study examined the associations between civic engagement in adolescence and outcomes during emerging adulthood among racial minority youth. Regression analyses found that civic engagement in adolescence is related to higher life satisfaction, civic participation, and educational attainment, and is related to lower rates of arrest in emerging adulthood. The findings suggest that adolescent civic engagement is most impactful in affecting civic and educational outcomes in emerging adulthood. The present study contributes to the literature by providing support for the long-term associations between adolescent civic engagement and multiple developmental domains in adulthood among an inner-city minority cohort.
PDF
