Cyanobacterial harmful algal blooms (cyanoHABs) in freshwater lakes across the globe are often combined with other stressors. Pharmaceutical pollution, especially antibiotics in water bodies, poses a ...potential hazard in aquatic ecosystems. However, how antibiotics influence the risk of cyanoHABs remains unclear. Here, we investigated the effects of norfloxacin (NOR), one of the most widely used antibiotics globally, to a bloom‐forming cyanobacterium (Microcystis aeruginosa) and a common green alga (Scenedesmus quadricauda), under both mono‐ and coculture conditions. Taxon‐specific responses to NOR were evaluated in monoculture. In addition, the growth rate and change in ratio of cyanobacteria to green algae when cocultured with exposure to NOR were determined. In monocultures of Microcystis, exposure to low concentrations of NOR resulted in decreases in biomass, chlorophyll a and soluble protein content, while superoxide anion content and superoxide dismutase activity increased. However, NOR at high concentration only slightly affected Scenedesmus. During the co‐culture trials of Microcystis and Scenedesmus, the 5 μg · L−1 NOR treatment increased the ratio of Microcystis to co‐cultured Scenedesmus by 47.2%. Meanwhile, although Scenedesmus growth was enhanced by 4.2% under NOR treatment in monoculture, it was conversely inhibited by 63.4% and 38.2% when co‐cultured with Microcystis with and without NOR, respectively. Our results indicate that antibiotic pollution has a potential risk to enhance the perniciousness of cyanoHABs by disturbing interspecific interaction between cyanobacteria and green algae. These results reinforce the need for scientists and managers to consider the influence of xenobiotics in shaping the outcome of interactions among multiple species in aquatic ecosystems.
ABSTRACT
Here, through single‐molecule real‐time sequencing, we present a high‐quality genome sequence of the Japanese larch (Larix kaempferi), a conifer species with great value for wood production ...and ecological afforestation. The assembled genome is 10.97 Gb in size, harboring 45,828 protein‐coding genes. Of the genome, 66.8% consists of repeat sequences, of which long terminal repeat retrotransposons are dominant and make up 69.86%. We find that tandem duplications have been responsible for the expansion of genes involved in transcriptional regulation and stress responses, unveiling their crucial roles in adaptive evolution. Population transcriptome analysis reveals that lignin content in L. kaempferi is mainly determined by the process of monolignol polymerization. The expression values of six genes (LkCOMT7, LkCOMT8, LkLAC23, LkLAC102, LkPRX148, and LkPRX166) have significantly positive correlations with lignin content. These results indicated that the increased expression of these six genes might be responsible for the high lignin content of the larches' wood. Overall, this study provides new genome resources for investigating the evolution and biological function of conifer trees, and also offers new insights into wood properties of larches.
Examination of the high‐quality genome of the Japanese larch Larix kaempferi reveals key features of this tree species and illustrates the crucial roles of genes encoding laccase and Class III peroxidases in wood properties of conifers.
Finding ways to reduce myocardial ischemia/reperfusion injury in the process of myocardial infarction has been an area of intense study in the field of heart disease. Recent studies have shown that ...long noncoding RNA (lncRNA) and autophagy play important roles in cardiovascular diseases. In our study, software analysis and dual‐luciferase reporter assays have shown that miR‐30a has binding sites on both AK088388 and Beclin‐1. Continuing experiments found that miR‐30a expression is downregulated, while the expressions of AK088388, Beclin‐1, and LC3‐II are upregulated in hypoxia/reoxygenation (H/R) cardiomyocytes; miR‐30a inhibits the expression of AK088388, Beclin‐1, and LC3‐II in H/R cardiomyocytes, while AK088388 promotes the expression of Beclin‐1 and LC3‐II and inhibits miR‐30a expression. AK088388 small interfering RNA and miR‐30a mimics can promote the viability of H/R cardiomyocytes, reduce lactate dehydrogenase release, and reduce apoptosis. Mutations of the miR‐30a binding site in AK088388 could not block the effects of miR‐30a mentioned above. Therefore, AK088388 can competitively bind to miR‐30a, promoting the expression of Beclin‐1 and LC3‐II, autophagy, and eventually cell damage. This finding provides new evidence for understanding the role of lncRNA in myocardial ischemia/reperfusion injury.
miR‐30a expression was downregulated, but the expressions of AK088388, Beclin‐1, and LC3‐II were upregulated under hypoxia/reoxygenation.
Targeted regulation of long noncoding RNA AK088388 and Beclin‐1 expressions by miR‐30a.
AK088388 regulates LC3‐II expression through the miR‐30a/Beclin‐1 pathway.
AK088388 regulates cardiomyocyte injury through the miR‐30a/Beclin‐1 pathway.
Summary
Brassinosteroids (BRs) play a critical role in plant growth, development and stress response; however, genetic evidence for the BR‐mediated integrated regulation of plant growth still remains ...elusive in crop species. Here, we clarified the function of DWARF (DWF), the key BR biosynthetic gene in tomato, in the regulation of plant growth and architecture, phytohormone homeostasis and fruit development by comparing wild type, d^im, a weak allele mutant impaired in DWF, and DWF‐overexpressing plants in tomato. Results showed that increases in DWF transcripts and endogenous BR level resulted in improved germination, lateral root development, CO2 assimilation and eventually plant growth as characterized by slender and compact plant architecture. However, an increase in DWF transcript down‐regulated the accumulation of gibberellin, which was associated with decreases in leaf size and thickness. BRs positively regulated lateral bud outgrowth, which was associated with decreased transcript of Aux/IAA3, and the ethylene‐dependent petiole bending and fruit ripening. Notably, overexpression of DWF did not significantly alter fruit yield per plant; however, increases by 57.4% and 95.3% might be estimated in fruit yield per square metre in two transgenic lines due to their compact architecture. Significantly, BR level was positively related with the carotenoid accumulation in the fruits. Taken together, our results demonstrate that BRs are actively involved in the regulation of multiple developmental processes relating to agronomical important traits.
Melatonin (N‐acetyl‐5‐methoxytryptamine) is an important biological hormone in many abiotic stress responses and developmental processes. In this study, the protective roles of melatonin were ...investigated by measuring the antioxidant defense system and photosynthetic characteristics in maize under salt stress. The results indicated that NaCl treatment led to the decrease in plant growth, chlorophyll contents and photochemical activity of photosystem II (PSII). However, the levels of reactive oxygen species increased significantly under salt stress. Meanwhile, we found that application of exogenous melatonin alleviated reactive oxygen species burst and protected the photosynthetic activity in maize seedlings under salt stress through the activation of antioxidant enzymes. In addition, 100 μM melatonin‐treated plants showed high photosynthetic efficiency and salinity. Immunoblotting analysis of PSII proteins showed that melatonin application alleviated the decline of 34 kDa PSII reaction center protein (D1) and the increase of PSII subunit S protein. Taken together, our study promotes more comprehensive understanding in the protective effects of exogenous melatonin in maize under salt stress, and it may be involved in activation of antioxidant enzymes and regulation of PSII proteins.
High-precision permeability prediction is of great significance to tight sandstone reservoirs. However, while considerable progress has recently been made in the machine learning based prediction of ...reservoir permeability, the generalization of this approach is limited by weak interpretability. Hence, an interpretable XGBoost model is proposed herein based on particle swarm optimization to predict the permeability of tight sandstone reservoirs with higher accuracy and robust interpretability. The porosity and permeability of 202 core plugs and 6 logging curves (namely, the gamma-ray (GR) curve, the acoustic curve (AC), the spontaneous potential (SP) curve, the caliper (CAL) curve, the deep lateral resistivity (RILD) curve, and eight lateral resistivity (RFOC) curve) are extracted along with three derived variables (i.e., the shale content, the AC slope, and the GR slope) as data sets. Based on the data preprocessing, global and local interpretations are performed according to the Shapley additive explanations (SHAP) analysis, and the redundant features in the data set are screened to identify the porosity, AC, CAL, and GR slope as the four most important features. The particle swarm optimization algorithm is then used to optimize the hyperparameters of the XGBoost model. The prediction results of the PSO-XGBoost model indicate a superior performance compared with that of the benchmark XGBoost model. In addition, the reliable application of the interpretable PSO-XGBoost model in the prediction of tight sandstone reservoir permeability is examined by comparing the results with those of two traditional mathematical regression models, five machine learning models, and three deep learning models. Thus, the interpretable PSO-XGBoost model is shown to have more advantages in permeability prediction along with the lowest root mean square error, thereby confirming the effectiveness and practicability of this method.
An efficient method for synthesizing thioester compounds under metal‐free conditions was reported. Thus, a series of indole‐substituted thioesters were easily obtained in the presence of PhICl2 ...(dichloroiodo‐benzene) starting from N‐arylthiocarbamates and indoles. This Newman‐Kwart‐type rearrangement reaction features metal free, base free, mild reaction conditions, good functional tolerance, and good yield, showing potential value for preparing some biologically and pharmaceutically active compounds.
In the presence of PhICl2, a series of thioester compounds containing indole structures were obtained starting from indoles and the masked thiols (N‐arylthiocarbamates). This method has the advantage of easily available starting material, metal and base‐free, simple operation, mild reaction conditions, and produces good yields.
To develop durable and low‐price catalysts of methanol oxidation to commercialize direct methanol fuel cell, many attempts have been made at fabricating Pt‐based hybrids by designing component‐, ...morphology‐, facet‐, integration‐pattern‐varied nanostructures, and have achieved considerable successes. However, most of present catalysts still lack robust catalytic durability especially owing to the corrosion of mixed carbon and the poor mechanical stability of catalyst layer. Herein, Te nanowire array is transformed at an air/water interface into a 3D Pt16Te hierarchical nanostructure via an interface‐confined galvanic replacement reaction. As‐formed Pt16Te nanostructure has an asymmetrical architecture composed of nanotroughs and nanopillars, and nanopillars are perpendicular to nanotroughs with a loose arrangement. Pt16Te hierarchical nanostructure has a “self‐supported” feature and, when directly used as the catalyst of methanol electrooxidation, exhibits superior catalytic activity (>four times larger in mass activity than state‐of‐the‐art Pt/C in either acidic or basic solution) and long‐term durability (after 500 cycles of cyclic voltammetric measurement, more than 55% of the initial specific activity remains whereas Pt/C only remains 22.2% in acidic solution and almost loses all activity in basic solution). This study fully demonstrates that designing “self‐supported” catalyst film may be the next promising step for improving the catalytic performance of Pt‐based hybrids.
A 3D Pt16Te hierarchical asymmetrical nanostructure composed of nanotrough and nanopillar arrays is fabricated from Te nanowire array located at an air/water interface. This morphology‐unique Pt16Te nanostructure exhibits a “self‐supported” feature and can be directly used as catalyst for electrooxidizing methanol, showing remarkable durability and catalytic activity in either acidic or basic solution.
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