A growing body of evidence suggests that dysbiosis of the human gut microbiota is associated with neurodegenerative diseases like Alzheimer's disease (AD) via neuroinflammatory processes across the ...microbiota-gut-brain axis. The gut microbiota affects brain health through the secretion of toxins and short-chain fatty acids, which modulates gut permeability and numerous immune functions. Observational studies indicate that AD patients have reduced microbiome diversity, which could contribute to the pathogenesis of the disease. Uncovering the genetic basis of microbial abundance and its effect on AD could suggest lifestyle changes that may reduce an individual's risk for the disease. Using the largest genome-wide association study of gut microbiota genera from the MiBioGen consortium, we used polygenic risk score (PRS) analyses with the "best-fit" model implemented in PRSice-2 and determined the genetic correlation between 119 genera and AD in a discovery sample (ADc12 case/control: 1278/1293). To confirm the results from the discovery sample, we next repeated the PRS analysis in a replication sample (GenADA case/control: 799/778) and then performed a meta-analysis with the PRS results from both samples. Finally, we conducted a linear regression analysis to assess the correlation between the PRSs for the significant genera and the APOE genotypes. In the discovery sample, 20 gut microbiota genera were initially identified as genetically associated with AD case/control status. Of these 20, three genera (Eubacterium fissicatena as a protective factor, Collinsella, and Veillonella as a risk factor) were independently significant in the replication sample. Meta-analysis with discovery and replication samples confirmed that ten genera had a significant correlation with AD, four of which were significantly associated with the APOE rs429358 risk allele in a direction consistent with their protective/risk designation in AD association. Notably, the proinflammatory genus Collinsella, identified as a risk factor for AD, was positively correlated with the APOE rs429358 risk allele in both samples. Overall, the host genetic factors influencing the abundance of ten genera are significantly associated with AD, suggesting that these genera may serve as biomarkers and targets for AD treatment and intervention. Our results highlight that proinflammatory gut microbiota might promote AD development through interaction with APOE. Larger datasets and functional studies are required to understand their causal relationships.
Abstract
Electrochemical intercalation of ions into the van der Waals gap of two-dimensional (2D) layered materials is a promising low-temperature synthesis strategy to tune their physical and ...chemical properties. It is widely believed that ions prefer intercalation into the van der Waals gap through the edges of the 2D flake, which generally causes wrinkling and distortion. Here we demonstrate that the ions can also intercalate through the top surface of few-layer MoS
2
and this type of intercalation is more reversible and stable compared to the intercalation through the edges. Density functional theory calculations show that this intercalation is enabled by the existence of natural defects in exfoliated MoS
2
flakes. Furthermore, we reveal that sealed-edge MoS
2
allows intercalation of small alkali metal ions (
e.g
., Li
+
and Na
+
) and rejects large ions (e.g., K
+
). These findings imply potential applications in developing functional 2D-material-based devices with high tunability and ion selectivity.
Novel Fe@C composites derived from metal-organic framework (MOF) were synthesized. Being subject to pyrolysis under different temperatures endows these Fe@Cs diverse physical-chemical properties, ...including morphology, crystal structure, defect level, magnetism, and most importantly, iron phase composition. Fe@C-800 consists mainly of Fe3C and α-Fe, thus possesses strong ferromagnetic properties, which imparts the ability to be separated and recycled. Its catalytic activity towards the activation of persulfate (PS) and the decomposition of sulfamethoxazole (SMX) was found to be the best among all the Fe@Cs, and this activity can be regenerated by simple heat treatment. Given the mixed form of iron and N-doped carbon, α-Fe/Fe3C species provide electrons for PS to decompose and generate sulfate radical (SO4·−), hydroxyl radical (·OH), and superoxide radical (O2·−), initiating the radical pathway for partial SMX degradation. The positively charged C atoms on PS bonded Fe@C, as well as the conversion of O2·− give rise to the generation of singlet oxygen (1O2), which was responsible for the non-radical pathway for SMX degradation. As a consequence, SMX was degraded to intermediates through five degradation pathways, and finally mineralized to inorganic molecules. The results indicate that Fe@C-800 has great potential to serve as a promising activator for persulfate-mediated environmental remediation.
Display omitted
•Novel porous carbonized MOF derivate Fe@Cs are fabricated for the first time.•Different pyrolysis temperature endows Fe@Cs diverse iron phases and magnetism.•The core-shell Fe@C-800 possesses strong ferromagnetic properties for recycling.•Fe@C-800/PS system displays high RSE of 20.9% compared to Fe2+/PS systems.•SMX degradation includes both radical and non-radical mechanisms.
Apple trees are grown worldwide, and consuming fresh apple fruit is associated with many health benefits. China produces about half of the world's apple supply. However, apple growing in China ...differs sharply from that in western countries in terms of the prevalent diseases and corresponding management strategies. For instance, family-owned small-scale orchards dominate China's apple industry, and manual bagging of fruit has been a long-standing practice for controlling fruit diseases. In recent years, rural labor shortages have been increasingly challenging the traditional production system, and China's apple industry is experiencing a rapid transition to much larger-scale enterprises featuring high-density orchards with advanced automation and mechanization. Associated with this transition are new challenges and grower demands that are changing the face of apple disease management. This Feature Article summarizes the ongoing transformation of China's apple industry in the context of sustainable disease management.
Transient neuromodulation can have long-lasting effects on neural circuits and motivational states
. Here we examine the dopaminergic mechanisms that underlie mating drive and its persistence in male ...mice. Brief investigation of females primes a male's interest to mate for tens of minutes, whereas a single successful mating triggers satiety that gradually recovers over days
. We found that both processes are controlled by specialized anteroventral and preoptic periventricular (AVPV/PVpo) dopamine neurons in the hypothalamus. During the investigation of females, dopamine is transiently released in the medial preoptic area (MPOA)-an area that is critical for mating behaviours. Optogenetic stimulation of AVPV/PVpo dopamine axons in the MPOA recapitulates the priming effect of exposure to a female. Using optical and molecular methods for tracking and manipulating intracellular signalling, we show that this priming effect emerges from the accumulation of mating-related dopamine signals in the MPOA through the accrual of cyclic adenosine monophosphate levels and protein kinase A activity. Dopamine transients in the MPOA are abolished after a successful mating, which is likely to ensure abstinence. Consistent with this idea, the inhibition of AVPV/PVpo dopamine neurons selectively demotivates mating, whereas stimulating these neurons restores the motivation to mate after sexual satiety. We therefore conclude that the accumulation or suppression of signals from specialized dopamine neurons regulates mating behaviours across minutes and days.
Display omitted
•The first study focusing on HO and O2− generation in the CaO2/Fe(II) system.•Reactive oxygen species and their generation pathways were proposed.•The strategy enhancing HO generation ...efficiency was developed.•A concept model using CaO2/Fe(II) oxidation technique was addressed.
Calcium peroxide (CaO2) is a stable hydrogen peroxide (H2O2) carrier, and the CaO2/Fe(II) system has been applied for treatment of various pollutants. It is commonly reported in the literature that hydroxyl radical (HO) and superoxide radical anions (O2−) are the two main reactive oxygen species (ROSs) generated in the CaO2/Fe(II) system. However, many of the reported results were deduced from degradation performance rather than specific testing of radical generation. Thus, the specific generation of ROSs and the influence of system conditions on ROSs yield are still unclear. To our knowledge, this is the first study specifically focusing on the generation of HO and O2− in the CaO2/Fe(II) system. Experimental conditions were optimized to investigate the production of HO and O2−. The results showed the influences of CaO2, Fe(II), and solution pH on HO and O2− generation, and the HO generation efficiency was reported for the first time. In addition, the ROSs generation pathways in the CaO2/Fe(II) system were elucidated. A strategy for enhancing HO yield is developed, based on the continuously dosing Fe(II). This proposed strategy has implications for the effective application of in situ chemical oxidation employing CaO2/Fe(II) for groundwater remediation.
Abstract
The fungus Magnaporthe oryzae causes devastating diseases of crops, including rice and wheat, and in various grasses. Strains from ryegrasses have highly unstable chromosome ends that ...undergo frequent rearrangements, and this has been associated with the presence of retrotransposons (Magnaporthe oryzae Telomeric Retrotransposons—MoTeRs) inserted in the telomeres. The objective of the present study was to determine the mechanisms by which MoTeRs promote telomere instability. Targeted cloning, mapping, and sequencing of parental and novel telomeric restriction fragments (TRFs), along with MinION sequencing of genomic DNA allowed us to document the precise molecular alterations underlying 109 newly-formed TRFs. These included truncations of subterminal rDNA sequences; acquisition of MoTeR insertions by ‘plain’ telomeres; insertion of the MAGGY retrotransposons into MoTeR arrays; MoTeR-independent expansion and contraction of subtelomeric tandem repeats; and a variety of rearrangements initiated through breaks in interstitial telomere tracts that are generated during MoTeR integration. Overall, we estimate that alterations occurred in approximately sixty percent of chromosomes (one in three telomeres) analyzed. Most importantly, we describe an entirely new mechanism by which transposons can promote genomic alterations at exceptionally high frequencies, and in a manner that can promote genome evolution while minimizing collateral damage to overall chromosome architecture and function.
The objective of this research was to investigate the retention and transport behavior of GenX in five natural porous media with similar median grain diameters but different geochemical properties. ...Surface tensions were measured to characterize surface activity. Miscible-displacement experiments were conducted under saturated conditions to characterize the magnitude of solid-phase adsorption, while unsaturated-flow experiments were conducted to examine the impact of air–water interfacial adsorption on retention and transport. The results from surface-tension measurements showed that the impact of solution composition is greater for the ammonium form of GenX than for the acid form, due to the presence of the NH4 counterion. The breakthrough curves for the experiments conducted under saturated conditions were asymmetrical, and a solute-transport model employing a two-domain representation of nonlinear, rate-limited sorption provided reasonable simulations of the measured data. The magnitudes of solid-phase adsorption were relatively small, with the highest adsorption associated with the medium containing the greatest amount of metal oxides. The breakthrough curves for the experiments conducted under unsaturated conditions exhibited greater retardation due to the impact of adsorption at the air–water interface. The contributions of air–water interfacial adsorption to GenX retention ranged from ∼24% to ∼100%. The overall magnitudes of retardation were relatively low, with retardation factors < ∼3, indicating that GenX has significant migration potential in soil and the vadose zone. To our knowledge, the results presented herein represent the first reported data for solid–water and air–water interfacial adsorption of GenX by soil. These data should prove useful for assessing the transport and fate behavior of GenX in soil and groundwater.
PDF
