Investor protection is associated with greater investment sensitivity to q and lower investment sensitivity to cash flow. Finance plays a role in causing these effects; in countries with strong ...investor protection, external finance increases more strongly with q, and declines more strongly with cash flow. We further find that q and cash flow sensitivities are associated with ex post investment efficiency; investment predicts growth and profits more strongly in countries with greater q sensitivities and lower cash flow sensitivities. The paper's findings are broadly consistent with investor protection promoting accurate share prices, reducing financial constraints, and encouraging efficient investment.
Small RNAs (sRNAs), an important type of pathogenicity factor, contribute to impairing host immune responses. However, little is known about sRNAs in Puccinia striiformis f. sp. tritici (Pst), one of ...the most destructive pathogens of wheat (Triticum aestivum L.). Here, we report a novel microRNA-like RNA (milRNA) from Pst termed microRNA-like RNA 1 (Pst milR1), which suppresses wheat defenses during wheat–Pst interactions.
We identified Pst-milR1 as a novel milRNA in Pst. Biological prediction and co-transformation showed that Pst-milR1 takes part in cross-kingdom RNA interference (RNAi) events by binding the wheat pathogenesis-related 2 (PR2) gene.
Silencing of the Pst-milR1 precursor resulted in increased wheat resistance to the virulent Pst isolate CYR31. PR2 knock-down plants increased the susceptibility of wheat to the avirulent Pst isolate CYR23. This suggests that Pst-milR1 represses the plant immune response by suppressing the expression of PR2.
Taking our findings together, we postulate that Pst-milR1 is an important pathogenicity factor in Pst, which acts as an effector to suppress host immunity. Our results provide significant new insights into the pathogenicity of the stripe rust pathogen.
Mikania micrantha is one of the top 100 worst invasive species that can cause serious damage to natural ecosystems and substantial economic losses. Here, we present its 1.79 Gb chromosome-scale ...reference genome. Half of the genome is composed of long terminal repeat retrotransposons, 80% of which have been derived from a significant expansion in the past one million years. We identify a whole genome duplication event and recent segmental duplications, which may be responsible for its rapid environmental adaptation. Additionally, we show that M. micrantha achieves higher photosynthetic capacity by CO
absorption at night to supplement the carbon fixation during the day, as well as enhanced stem photosynthesis efficiency. Furthermore, the metabolites of M. micrantha can increase the availability of nitrogen by enriching the microbes that participate in nitrogen cycling pathways. These findings collectively provide insights into the rapid growth and invasive adaptation.
It is of great interest to elucidate underlying mechanisms to maintain stability of anaerobic digestion, an important process in waste treatment. By operating triplicate anaerobic digesters ...continuously for two years, we found that microbial community composition shifted over time despite stable process performance. Using an association network analysis to evaluate microbial interactions, we detected a clear successional pattern, which exhibited increasing modularity but decreasing connectivity among microbial populations. Phylogenetic diversity was the most important factor associated with network topology, showing positive correlations with modularity but negative correlations with network complexity, suggesting induced niche differentiation over time. Positive, but not negative, correlation strength was significantly related (p < 0.05) to phylogeny. Furthermore, among populations exhibiting consistent positive correlations across networks, close phylogenetic linkages were evident (e.g. Clostridiales organisms). Clostridiales organisms were also identified as keystone populations in the networks (i.e., they had large effects on other species), suggestive of an important role in maintaining process stability. We conclude that microbial interaction dynamics of anaerobic digesters evolves over time during stable process performance.
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•Triplicate anaerobic digesters were operated continuously for two years.•A successional pattern of microbial interactions was observed despite process stability.•Clostridiales organisms were keystone populations in maintaining stable performance.•Phylogeny could shape positive but not negative interactions among microorganisms.
•A formic acid-assisted photolysis of UO22+ initiated chromogenic reaction is fabricated for colorimetric detection of UO22+.•This colorimetric assay realizes visualization of UO22+ at a ...concentration of 0.5 μM.•It possesses excellent selectivity over common inorganic ions with even 50-fold higher concentration than UO22+.
Current strategies for visual detection of uranyl ion (UO22+) often require DNAzymes and organophosphorus receptors as well as various nanomaterials that may affect the selectivity, sensitivity, and accuracy in a complicated environment. Here, we circumvent these drawbacks by introducing a formic acid (FA)-assisted photolysis of UO22+ initiated chromogenic reaction for specific recognition element-free colorimetric detection of UO22+. The colorless 2, 2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) is oxidized by the superoxide anion from the photolysis of UO22+ to generate green ABTS radical, which enables the determination of UO22+ at a concentration of 0.5 μM with the naked eye. The present colorimetric assay is able to determine concentrations of UO22+ from 0.1 to 100 μM, with a limit of detection as low as 0.01 μM. Impressively, the specific recognition element-free colorimetric assay possesses excellent selectivity over common inoganic ions with even 50-fold higher concentration than UO22+. In addition to good sensitivity and selectivity, this colorimetric assay is also capable of determining UO22+ in natural water samples with satisfactory recoveries.
Aims
Soil bacterial communities play vital roles in subtropical broad-leaved forests (SBFs), however, the mechanisms regulating their formation remain poorly understood. The present work aimed to ...address this question.
Methods
We used dIVI (Important Value Index of deciduous canopy trees) to quantitively classify three SBFs. Soil bacterial traits such as community composition, diversity and potential interactions (via network analyses) were studied. The relationship between bacterial community composition and environmental factors was analyzed.
Results
SBFs were determined as a deciduous forest (DBF, dIVI = 0.99), a mixed forest (MBF, dIVI = 0.52) and an evergreen forest (EBF, dIVI = 0.19). Soil bacterial communities were different considerably among vegetation types, which was largely attributed to soil pH, dIVI and plant diversity, in which soil pH exerted stronger impacts than the others (coefficients of partial Mantel tests: 0.87 for soil pH versus 0.35 for dIVI, 0.26 for plant diversity). Compared to the MBF and the EBF, the DBF exhibited significantly higher bacterial diversity and more intensive potential interactions.
Conclusions
This study implies that soil pH, vegetation type and plant diversity are key driving forces of soil bacterial community composition in SBFs, which improves our understanding of mechanisms regulating soil bacterial community composition.
We examine the relation between bidder returns and the probability of chief executive officer (CEO) turnover in acquiring firms. Using a sample of 714 acquisitions during 1990 to 1998, we find that ...47% of CEOs of acquiring firms are replaced within 5 years, including 27% by internal governance, 16% by takeovers, and 4% by bankruptcy. A significant inverse relation exists between bidder returns and the likelihood of CEO turnover. This relation is not associated with governance structure. It also is not significantly different in stock versus cash acquisitions, which appears to be inconsistent with Shleifer and Vishny's theory of "stock market driven" acquisitions.
We examine the determinants of the size and composition of corporate boards for a sample of 82 US companies that survived during the period 1935-2000. Our hypotheses lead to predictions that firm ...size, growth opportunities, merger activity, and geographical expansion are important determinants of these board characteristics. We find empirical evidence that the four variables are significant determinants of the size and/or composition of boards. After controlling for these determinants of board characteristics, we find no robust relation between firm performance and either board size or composition.
Aim
The factors driving microbial community β‐diversity (variation in composition) at different spatial scales yield fundamental insights into the mechanisms that maintain ecosystem biodiversity, ...which as yet are uncertain. Here, we explore whether spatial scale‐dependent patterns of β‐diversity vary between microbial functional groups and bacterial taxa (i.e., diazotrophic and bacterial communities) across local to regional scales (from metres to hundreds of kilometres).
Location
Eastern China.
Time period
October and November 2015.
Major taxa studied
Diazotrophic and bacterial communities.
Methods
We use two complementary statistical tools to unveil biotic mechanisms (i.e., species association) underlying variation in β‐diversity of diazotrophic and bacterial communities. We examined distance–decay slopes of both communities at the local (1–113 m), meso‐ (3.4–39 km) and regional (103–668 km) scales. We used an environmentally constrained checkerboard score and topological features of association networks as indices of species association. We then calculated contributions of species association, abiotic factors and geographical distance to explain community β‐diversity. The scale‐dependent distance–decay relationships were also examined in ubiquitous (high occupancy across samples) and endemic communities of diazotrophs and bacteria.
Results
Diazotrophs displayed steeper distance–decay slopes than bacteria, suggesting that the β‐diversity of diazotrophic communities was more variable. The distance–decay slopes were dependent on spatial scales in both communities, owing to different contributions of geographical distance, abiotic factors and species association at three spatial scales. Intriguingly, species association was greater and contributed more to community β‐diversity than other forces at the local scale, implying that species association could greatly alter community structures.
Main conclusions
Drivers of diazotrophic and bacterial community β‐diversity depended on spatial scales, resulting in different distance–decay patterns. Moreover, this was the first study to use two methods to demonstrate that species association played important, but as yet unrecognized, roles in driving spatial scale‐dependent β‐diversity.
A novel magnetic hollow bimetallic zinc/cobalt-based zeolitic imidazolate framework (MHB-Zn/Co-ZIF-8) was prepared via a microwave-assisted chemical etching in methanol. The structure, morphology, ...and specific surface area were characterized by X-ray diffraction and FTIR spectroscopy, scanning and transmission electron microscopy, and N
2
adsorption. The hollow nanostructures with high internal specific surface area, abundant active sites, and reduced aggregation of nanoparticles endow the hollow zeolitic imidazolate framework (ZIF) nanoparticle with high chemical stability, desirable durability, and excellent adsorption abilities. The MHB-Zn/Co-ZIF-8 nanoparticle was used as an effective sorbent for magnetic solid-phase extraction (MSPE) of trace aflatoxins B
1
, B
2
, G
1
, and G
2
from fruit juice and fruit samples. The main parameters affecting the efficiency of MSPE procedures were investigated and optimized. The results show that, under optimized conditions, enrichment factors ranging from 67- to 355-fold are obtained for the target analytes. The method is linear in the range 1.0 to 100.0 ng mL
−1
with correlation coefficients (
R
2
) from 0.9960 to 0.9992. The limits of detection of four aflatoxins are in the range 0.18 to 1.50 ng mL
−1
and the average recoveries range from 75.1 to 102.4%, with relative standard deviations (RSDs) less than 13.6%. This work presents the excellent extraction performance of aflatoxins B
1
, B
2
, G
1
, and G
2
on MHB-Zn/Co-ZIF-8. In addition, the applicability of the MSPE coupling with ultrahigh-performance liquid chromatography-ion trap tandem mass spectrometry (UHPLC-IT-MS
n
) for trace analysis in complex matrices is shown.
Graphical abstract
Schematic presentation of magnetic hollow bimetallic zinc/cobalt zeolitic imidazolate framework as sorbent for efficiently enriching aflatoxins B
1
, B
2
, G
1
, and G
2
from fruit juice samples prior to ultrahigh-performance liquid chromatography-ion trap tandem mass spectrometry (UHPLC-IT-MS
n
) determination.
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