Maleimide is widely applied in many fields, especially in antibody–drug conjugations and peptide drugs. Herein, we develop a strategy for the C–H alkenylation of tryptophan and tryptophan-containing ...peptides, providing a synthetic route of decorating maleimide on peptides. The method has a high tolerance of functional groups and protecting groups. Furthermore, this method was applied to prepare peptide conjugation with molecules such as drugs and fluorescence probes. Moreover, macrocyclic peptides were obtained via this reaction.
China has been seriously affected by particulate matter (PM) and gaseous pollutants in the atmosphere. In this study, we systematically analyse the spatio-temporal patterns of PM2.5, PM10, SO2, CO, ...NO2, and O3 and the associated health risks, using data collected from 1498 national air quality monitoring sites. An analysis of the averaged data from all the sites indicated that, from 2015 to 2018, annual mean concentrations of PM2.5, PM10, SO2 and CO declined by 3.2 μg m−3, 3.7 μg m−3, 3.9 μg m−3, and 0.1 mg m−3, respectively. In contrast, those of NO2 and O3 increased at rates of 0.4 and 3.1 μg m−3, respectively. Except for O3, the annual mean concentrations of all pollutants were generally the highest in North China and lowest in the Tibetan Plateau. The concentrations were generally higher in the north of the country than in the south. In all regions of China, the pollutant concentrations were the highest in winter and lowest in summer, except for O3, which showed an opposite seasonal pattern. Overall, the seasonal mean concentrations of all the pollutants (except for O3) significantly decreased between the same seasons in 2018 and 2015, whereas the seasonal mean O3 concentrations generally significantly increased, and/or remained at stable levels in all four seasons except for winter. Diurnal variations of all pollutants (except for O3) exhibited a bimodal pattern with peaks between 8:00 and 11:00 a.m. and 9:00 and 12:00 p.m., whereas O3 exhibited a unimodal pattern with maximum values between 5:00 and 7:00 p.m. No significant differences in the daily mean concentrations of all pollutants were found between weekdays and weekends in all regions, except for PM2.5 and PM10 in Northeast China. In Northwest China and Southeast China, PM2.5 showed stronger correlations with NO2 relative to SO2, suggesting that NOx emission control may be more effective than SO2 emission control for alleviating PM2.5 formation. Compared with 2015, the total PM2.5-attributable mortality, number of respiratory and cardiovascular diseases, and incidence of chronic bronchitis decreased overall by 23.4%–26.9% in 2018. In contrast, for O3-attributable deaths, there was an increase of 18.9%. Our study not only improves the understanding of the spatial and temporal patterns of air pollutants in China, but also highlights that synchronous control of PM2.5 and O3 pollution should be implemented to achieve dual benefits in protecting human health.
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•Hourly concentrations of six air pollutants were analysed at1498 sites in China.•Except O3 and NO2, all the pollutants concentrations decreased annually.•O3 peaked in the Tibetan Plateau, whereas the other pollutants in North China.•The diurnal variations of all pollutants displayed a bimodal pattern except for O3.•O3 pollution should be reduced to maximise the protection of human health.
Our study highlights the large variability in the spatial and temporal patterns of air pollutants over China and indicates that O3 pollution should be given greater consideration.
•Aromatic systems are the electron-accepting moieties facilitating PCP dechlorination.•Sugar-amine condensation is the forming way of redox groups in protein-rich composts.•Polyphenol pathway mainly ...exists in lignocellulose- and lignin-rich composts.•Seven groups of bacterial communities involved in synthetic and catabolic pathway.
Humic acids (HAs) can function as electron mediators for contaminants transformation in different environments. The humus respiration can facilitate pentachlorophenol (PCP) dechlorination during different biowastes composting. However, different characteristics of synthetic pathways of redox functional groups within HAs during different biowastes composting have never been characterized. Herein, we assessed the synthetic pathways of redox functional groups within HAs from protein-, lignocellulose-, and lignin-rich composts that facilitated the microbially reductive dechlorination of PCP, respectively. The results show that the aromatic systems are the major electron-accepting moieties of HAs and function as electron shuttles to facilitate the PCP dechlorination. Amino acid and reducing sugar are the major precursors for the synthesis of redox functional groups within HAs in protein-rich composts, and polyphenols and amino acids are discerned as the significant components to synthesize redox functional groups of HAs in lignocellulose- and lignin-rich composts. Seven groups of bacterial communities based on relationships among remarkable precursors, key bacterial communities, and redox functional groups within HAs are classified as participants in the precursors’ catabolism and aromatic system’ anabolism. Furthermore, the significant environmental factors on the synthetic pathways of redox functional groups within HAs in composting are confirmed by structural equation models. Conclusively, the regulating methods for promoting PCP dechlorination by HAs during different biowastes composting are proposed. Our results can help in understanding the distinct formative mechanisms of redox functional groups within HAs during different biowastes composting, providing insights into a classification-oriented approach for recycling utilization of different biowastes.
SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) is the etiological agent responsible for the global COVID-19 (coronavirus disease 2019) outbreak. The main protease of SARS-CoV-2, M
, is ...a key enzyme that plays a pivotal role in mediating viral replication and transcription. We designed and synthesized two lead compounds (
and
) targeting M
Both exhibited excellent inhibitory activity and potent anti-SARS-CoV-2 infection activity. The x-ray crystal structures of SARS-CoV-2 M
in complex with
or
, both determined at a resolution of 1.5 angstroms, showed that the aldehyde groups of
and
are covalently bound to cysteine 145 of M
Both compounds showed good pharmacokinetic properties in vivo, and
also exhibited low toxicity, which suggests that these compounds are promising drug candidates.
Background and aims
Harnessing soil microbiomes is a major demand for development of sustainable and productive agriculture. Here we aimed to assess the impact of two different types of organic ...material amendments in combination with chemical fertilizer on the plant-soil microbiota in maize farming and its link to soil fertility and crop productivity.
Methods
Soils and roots were collected from a long-term wheat-maize rotation system involving three experimental treatments: chemical fertilizer (CF); chemical fertilizer plus seasonal application of manure (OM); and chemical fertilizer plus one-time application of peat and vermiculite (PV). Crop residues were returned in all three treatments each season. Bacterial 16S rRNA gene and fungal ITS sequencing were conducted to elucidate the treatment-specific response of the microbiota in bulk soil, rhizosphere soil, and root compartment.
Results
Relative to CF and OM treatments, PV amendment led to significant increases in soil organic carbon (SOC) content, aboveground plant biomass, and grain yield over the five-year field study. The PV-induced changes in microbial composition involved the greatest treatment-specific “effect size” on indicator ASVs (amplicon sequence variants) in bulk and rhizosphere soils. The number of interactions was more than doubled in the PV co-occurrence network relative to those in the CF and OM co-occurrence networks. Potential beneficial microbes, such as
Glomeromycota
(arbuscular mycorrhiza),
Basidiomycota
, and various members of the
Actinobacteria
and
Burkholderiales
, were most enriched in the root compartment of the PV treatment.
Conclusions
Peat-vermiculite enhanced microbiota-driven soil fertility and crop productivity, thereby providing new insights into plant-soil-microbiota interactions that can be harnessed for smart farming.
Enhancing soil phosphate solubilization is a promising strategy for agricultural sustainability, while little is known about the mechanisms of how microorganisms cope with differing phosphorus ...availability. Using a combination of genome-resolved metagenomics and amplicon sequencing, we investigated the microbial mechanisms involved in phosphorus cycling under three agricultural treatments in a wheat-maize rotation system and two natural reforestation treatments. Available soil phosphorus was the key factor shaping bacterial and fungal community composition and function across our agricultural and reforestation sites. Membrane-bound quinoprotein glucose dehydrogenase (PQQGDH) and exopolyphosphatases (PPX) governed microbial phosphate solubilization in agroecosystems. In contrast, genes encoding glycerol-3-phosphate transporters (
,
, and
) displayed a significantly greater abundance in the reforestation soils. The
gene encoding PQQGDH was found to be the best determinant for bioavailable soil phosphorus. Metagenome-assembled genomes (MAGs) affiliated with
and
were obtained from agricultural soils. Their MAGs harbored not only
but also the
gene encoding low-affinity phosphate transporters. MAGs obtained from reforestation soils were affiliated with
and
. These contain
genes but no
, and thereby are indicative of a phosphate transporter strategy. Our study demonstrates that knowledge of distinct microbial phosphorus acquisition strategies between agricultural and reforestation soils could help in linking microbial processes with phosphorus cycling.
The soil microbiome is the key player regulating phosphorus cycling processes. Identifying phosphate-solubilizing bacteria and utilizing them for release of recalcitrant phosphate that is bound to rocks or minerals have implications for improving crop nutrient acquisition and crop productivity. In this study, we combined functional metagenomics and amplicon sequencing to analyze microbial phosphorus cycling processes in natural reforestation and agricultural soils. We found that the phosphorus acquisition strategies significantly differed between these two ecosystems. A microbial phosphorus solubilization strategy dominated in the agricultural soils, while a microbial phosphate transporter strategy was observed in the reforestation soils. We further identified microbial taxa that contributed to enhanced phosphate solubilization in the agroecosystem. These microbes are predicted to be beneficial for the increase in phosphate bioavailability through agricultural practices.
The incorporation of rice residues into paddy fields strongly enhances methane production and emissions. Although the decomposition processes of plant residues in rice field soil has been documented, ...the structure and dynamics of the microbial communities involved are poorly understood. The purpose of the present study was to determine the dynamics of short-chain fatty acids and the structure of bacterial communities during residue decomposition in a rice field soil. The soil was anaerobically incubated with the incorporation of rice root or straw residues for 90 days at three temperatures (15, 30, and 45°C). The dynamics of fatty acid intermediates showed an initial cumulative phase followed by a rapid consumption phase and a low-concentration quasi-steady state. Correspondingly, the bacterial populations displayed distinct successions during residue decomposition. Temperature showed a strong effect on the dynamics of bacterial populations. Members of Clostridium (clusters I and III) were most dominant in the incubations, particularly in the early successions. Bacteroidetes and Chlorobi were abundant in the later successions at 15 and 30°C, while Acidobacteria were selected at 45°C. We suggest that the early successional groups are responsible for the decomposition of the easily degradable fraction of residues, while the late successional groups become more important in decomposing the less-degradable or resistant fraction of plant residues. The bacterial succession probably is related to resource availability during residue decomposition. The fast-growing organisms are favored at the beginning, while the slow-growing bacteria are better adapted in the later stages, when substrate availability is limiting.
Background The short-term prognosis of stroke patients is mainly influenced by the severity of the primary disease at admission and the trend of disease development during the acute phase (1-7 days ...after admission). Objective The aim of this study is to explore the relationship between the bioelectrical impedance analysis (BIA) parameter trajectories during the acute phase of stroke patients and their short-term prognosis, and to investigate the predictive value of the prediction model constructed using BIA parameter trajectories and clinical indicators at admission for short-term prognosis in stroke patients. Methods A total of 162 stroke patients were prospectively enrolled, and their clinical indicators at admission and BIA parameters during the first 1-7 days of admission were collected. A Group-Based Trajectory Model (GBTM) was employed to identify different subgroups of longitudinal trajectories of BIA parameters during the first 1-7 days of admission in stroke patients. The random forest algorithm was applied to screen BIA parameter trajectories and clinical indicators with predictive value, construct prediction models, and perform model comparisons. The outcome measure was the Modified Rankin Scale (mRS) score at discharge. Results PA in BIA parameters can be divided into four separate trajectory groups. The incidence of poor prognosis (mRS: 4-6) at discharge was significantly higher in the "Low PA Rapid Decline Group" (85.0%) than in the "High PA Stable Group " (33.3%) and in the "Medium PA Slow Decline Group "(29.5%) (all P < 0.05). In-hospital mortality was the highest in the "Low PA Rapid Decline Group" (60%) compared with the remaining trajectory groups (P < 0.05). Compared with the prediction model with only clinical indicators (Model 1), the prediction model with PA trajectories (Model 2) demonstrated higher predictive accuracy and efficacy. The area under the receiver operating characteristic curve (AUC) of Model 2 was 0.909 95% CI 0.863, 0.956, integrated discrimination improvement index (IDI), 0.035 (P < 0.001), and net reclassification improvement (NRI), 0.175 (P = 0.031). Conclusion PA trajectories during the first 1-7 days of admission are associated with the short-term prognosis of stroke patients. PA trajectories have additional value in predicting the short-term prognosis of stroke patients.
A novel series of peptidomimetic aldehydes was designed and synthesized to target 3C protease (3Cpro) of enterovirus 71 (EV71). Most of the compounds exhibited high antiviral activity, and among ...them, compound 18p demonstrated potent enzyme inhibitory activity and broad-spectrum antiviral activity on a panel of enteroviruses and rhinoviruses. The crystal structure of EV71 3Cpro in complex with 18p determined at a resolution of 1.2 Å revealed that 18p covalently linked to the catalytic Cys147 with an aldehyde group. In addition, these compounds also exhibited good inhibitory activity against the 3CLpro and the replication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), especially compound 18p (IC50 = 0.034 μM, EC50 = 0.29 μM). According to our previous work, these compounds have no reasons for concern regarding acute toxicity. Compared with AG7088, compound 18p also exhibited good pharmacokinetic properties and more potent anticoronavirus activity, making it an excellent lead for further development.
This study demonstrated that a combined heterotrophic and autotrophic denitrification (HAD) process is highly effective for the simultaneous removal of acetate, nitrate, and sulfide at an efficiency ...of 100, 80, and 100 %, respectively. In the HAD system, simultaneous sulfide, acetate, and nitrate removals were observed, which indicated that heterotrophic and autotrophic denitrification occurred simultaneously. When the sulfide was existed in HAD reactor, the main product of sulfide biooxidation was S⁰. Once the sulfide was exhausted, the sulfate concentration in the HAD reactor increased and became the main end product. These results provided an alternative method to control the end sulfide biooxidation product by online monitoring sulfide concentration. Nearly half (43 %) of the total clones in our mix-trophic reactor were amphitrophy denitrifiers. The autotrophic denitrifiers, heterotrophic denitrifiers, and amphitrophy denitrifiers coexisted in the HAD reactor to complete the denitrification process. Retrieved bacterial 16S rRNA gene clones affiliated with uncultured Xanthomonadaceae, Thauera, Thiobacillus, and Chromatiales were dominant.
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