154 research outputs found
Effects of Glyphosate-Resistant Genetically Modified Soybean on Blood Biochemical Indexes, Hepatopancreatic Antioxidant Capacity and Tissue Morphology of Cyprinus carpio
The juvenile carps (Cyprinus carpio) were fed diets with four protein sources (15% and 30% glyphosate-resistant genetically modified (GM) named GM 15 and GM 30, respectively, and 15% and 30% non-genetically modified (NGM) soybean named NGM 15 and NGM 30) for 180 days. Results showed that alkaline phosphatase (ALP) activity for the GM30 group was significantly lower than that of the NGM30 group. The activity of glutathione peroxidase (GSH-Px) in the hepatopancreas of carp for the GM30 group was significantly higher than that of the NGM15 group (P0.05). This study indicates that it may aggravate the damage degree of intestinal epithelial cells of carp and more easily cause liver cell damage in the short term when the amount of GM soybean in the feeds was 30%. Therefore, higher glyphosate-resistant GM soybean may have adverse effects on the carp's serum, intestinal, and hepatopancreas and considerably reduce the hepatopancreatic carp's antioxidant capacity
Bryophyte diversity is related to vascular plant diversity and microhabitat under disturbance in karst caves
Plant diversity, habitat properties, and their relationships in karst caves remain poorly understood. We surveyed vascular plant and bryophyte diversities and measured the habitat characteristics in six karst caves in south China with different disturbance histories (one had been disturbed by poultry feeding, three had been disturbed by tourism, and two were undisturbed). The plant diversity differences among the six caves were analyzed using cluster analysis, and the relationships of plant diversity and microhabitat were assessed using canonical correspondence analysis. We found a total of 43 angiosperm species from 27 families, 20 lycophyte and fern species from 9 families, and 20 species of bryophytes from 13 families in the six caves. Habitat characteristics including light intensity, air relative humidity, air temperature, and soil properties varied among the caves. The plant diversity in karst caves was not rich, but the species composition was unique. The caves with high disturbance had the lowest species richness, numbers of individuals, and Shannon-Wiener diversity indices but the highest Simpson’s dominance indices. The caves with less disturbance had the highest numbers of species, numbers of individuals, and Shannon-Wiener diversity indices but the lowest Simpson’s dominance indices. The disturbed caves were often dominated by drought-tolerant, tenacious mosses (bryophytes), while the relatively undisturbed caves contained abundant liverworts (bryophytes), which were better adapted to humid environments. Plant diversity in karst caves was closely related to habitat heterogeneity, light and water status, and nutrient availability. Tourism and poultry farming were associated with the degradation of vegetation in some karst caves. Protecting and restoring bryophytes might facilitate the settlement, growth, and succession of vascular plants in karst caves. Bryophytes can be used as indicators of overall plant diversity and restoration status in karst caves
BlockEmulator: An Emulator Enabling to Test Blockchain Sharding Protocols
Numerous blockchain simulators have been proposed to allow researchers to
simulate mainstream blockchains. However, we have not yet found a testbed that
enables researchers to develop and evaluate their new consensus algorithms or
new protocols for blockchain sharding systems. To fill this gap, we develop
BlockEmulator, which is designed as an experimental platform, particularly for
emulating blockchain sharding mechanisms. BlockEmulator adopts a lightweight
blockchain architecture such that developers can only focus on implementing
their new protocols or mechanisms. Using layered modules and useful programming
interfaces offered by BlockEmulator, researchers can implement a new protocol
with minimum effort. Through experiments, we test various functionalities of
BlockEmulator in two steps. Firstly, we prove the correctness of the emulation
results yielded by BlockEmulator by comparing the theoretical analysis with the
observed experiment results. Secondly, other experimental results demonstrate
that BlockEmulator can facilitate the measurement of a series of metrics,
including throughput, transaction confirmation latency, cross-shard transaction
ratio, the queuing size of transaction pools, workload distribution across
blockchain shards, etc. We have made BlockEmulator open-source in Github
Inducing piezoelectricity in distorted rutile TiO2 for enhanced tetracycline hydrochloride degradation through photopiezocatalysis
Various material design strategies have been developed to enhance photocatalytic performance of TiO2. However, no report is available on applications of the photopiezocatalysis strategy on TiO2 due to its lack of piezoelectricity. Here we developed a low-temperature molten salt etching process to create rutile TiO2 nanoparticles by etching [MgO6] octahedrons away from MgTiO3 by molten NH4Cl, during which a lattice distortion occurred in TiO2. The lattice distortion broke the structure symmetry of rutile TiO2 and subsequently endowed these rutile TiO2 nanoparticles with an unusual piezoelectric response with the maximum effective piezoelectric coefficient (d33) of ~41.6 pm/V, which had not previously been found in TiO2 photocatalysts. Thus, the photopiezocatalysis strategy was applied for the first time to enhance the photocatalytic performance of these TiO2 nanoparticles. The creation of lattice distortion to induce piezoelectricity could be extended to other photocatalysts that the photopiezocatalysis strategy has not been applied to and may generate novel functionalities for various technical applications
Fluorescence-Based Flow Sorting in Parallel with Transposon Insertion Site Sequencing Identifies Multidrug Efflux Systems in Acinetobacter baumannii
Multidrug efflux pumps provide clinically significant levels of drug resistance in a number of Gram-negative hospital-acquired pathogens. These pathogens frequently carry dozens of genes encoding putative multidrug efflux pumps. However, it can be difficult to determine how many of these pumps actually mediate antimicrobial efflux, and it can be even more challenging to identify the regulatory proteins that control expression of these pumps. In this study, we developed an innovative high-throughput screening method, combining transposon insertion sequencing and cell sorting methods (TraDISort), to identify the genes encoding major multidrug efflux pumps, regulators, and other factors that may affect the permeation of antimicrobials, using the nosocomial pathogen Acinetobacter baumannii. A dense library of more than 100,000 unique transposon insertion mutants was treated with ethidium bromide, a common substrate of multidrug efflux pumps that is differentially fluorescent inside and outside the bacterial cytoplasm. Populations of cells displaying aberrant accumulations of ethidium were physically enriched using fluorescence-activated cell sorting, and the genomic locations of transposon insertions within these strains were determined using transposon-directed insertion sequencing. The relative abundance of mutants in the input pool compared to the selected mutant pools indicated that the AdeABC, AdeIJK, and AmvA efflux pumps are the major ethidium efflux systems in A. baumannii. Furthermore, the method identified a new transcriptional regulator that controls expression of amvA. In addition to the identification of efflux pumps and their regulators, TraDISort identified genes that are likely to control cell division, cell morphology, or aggregation in A. baumannii.
IMPORTANCE
Transposon-directed insertion sequencing (TraDIS) and related technologies have emerged as powerful methods to identify genes required for bacterial survival or competitive fitness under various selective conditions. We applied fluorescence-activated cell sorting (FACS) to physically enrich for phenotypes of interest within a mutant population prior to TraDIS. To our knowledge, this is the first time that a physical selection method has been applied in parallel with TraDIS rather than a fitness-induced selection. The results demonstrate the feasibility of this combined approach to generate significant results and highlight the major multidrug efflux pumps encoded in an important pathogen. This FACS-based approach, TraDISort, could have a range of future applications, including the characterization of efflux pump inhibitors, the identification of regulatory factors controlling gene or protein expression using fluorescent reporters, and the identification of genes involved in cell replication, morphology, and aggregation
Avoiding the Big-Rip Jeopardy in a Quintom Dark Energy Model with Higher Derivatives
In the framework of a single scalar field quintom model with higher
derivative, we construct in this paper a dark energy model of which the
equation of state (EOS) crosses over the cosmological constant boundary.
Interestingly during the evolution of the universe happens just for a
period of time with a distinguished feature that starts with a value above
-1, transits into . This avoids the Big Rip
jeopardy induced by .Comment: 7 pages, 3 figure
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