Exposure to polystyrene nanoparticles at predicted environmental concentrations enhances toxic effects of Acinetobacter johnsonii AC15 infection on Caenorhabditis elegans.

Nanoplastics and microbial pathogens are both widely distributed in the environment; however, their combined toxicity remains largely unclear. Using Caenorhabditis elegans as an animal model, we examined the possible effect of exposure to polystyrene nanoparticle (PS-NP) in Acinetobacter johnsonii AC15 (a bacterial pathogen) infected animals. Exposure to PS-NP at the concentrations of 0.1-10 µg/L significantly enhanced the toxicity of Acinetobacter johnsonii AC15 infection on lifespan and locomotion behaviors. In addition, after exposure to 0.1-10 µg/L PS-NP, the accumulation of Acinetobacter johnsonii AC15 in body of nematodes was also increased. Meanwhile, the innate immune response indicated by the increase of antimicrobial gene expressions in Acinetobacter johnsonii AC15 infected nematodes was suppressed by exposure to 0.1-10 µg/L PS-NP. Moreover, expressions of egl-1, dbl-1, bar-1, daf-16, pmk-1, and elt-2 governing the bacterial infection and immunity in Acinetobacter johnsonii AC15 infected nematodes were further inhibited by exposure to 0.1-10 µg/L PS-NP. Therefore, our data suggested the possible exposure risk of nanoplastic at predicted environmental concentrations in enhancing the toxic effects of bacterial pathogens on environmental organisms.

Seasonal pollution and surface characteristics of microplastics in surface water in the Wanzhou section of the Three Gorges Reservoir, China.

The pollution of freshwater environments with microplastics (MPs) has attracted increasing attention owing to their threats to aquatic ecosystems and human health. Here, we sampled and analyzed MPs from mainstream, tributary, and backwater areas in the Wanzhou section of the Three Gorges Reservoir (TGR) in impoundment and flood periods. Microplastic pollution was the most severe in the backwater areas. The average abundance of MPs reached the highest value in the flood period (5.27±3.47×107 items km-2), which was 3-5 times that in the impoundment period. In the 0.3-5 mm size class, the 1-5 mm fraction was the most abundant, accounting for more than 81% in the flood period and 68% of the total MP particle abundance in the impoundment period in the mainstream and backwater areas. However, 0.3-1 mm MPs contributed more than 50% in the tributaries during the impoundment period. Polystyrene, polypropylene, and polyethylene MPs were detected in foam, fragment, sheet, and line-shaped MP particles. White, opaque, foamed polystyrene MPs contributed 32-81% to total MP particle abundance in the watershed. Microplastic particle surfaces showed signs of damage and oxidation, and ten different elements were found. Oxygen was clustered on the surface of foam and fragment MPs. Microplastic pollution was severe in the Wanzhou watershed. Especially in the backwater areas, oxidized MPs of variable shapes derived mainly from surface runoff in the flood period and sewage discharge in the impoundment period were abundant. The results of this study contribute to understanding seasonal pollution patterns and surface characteristics of MPs in the TGR and similar watersheds.

Exposure to Nanoplastic Particles Enhances Acinetobacter Survival, Biofilm Formation, and Serum Resistance.

The interaction between nanoplastics and bacteria remains still largely unclear. In this study, we determined the effect of nanopolystyrene particle (NP) on a bacterial pathogen of Acinetobacter johnsonii AC15. Scanning electron microscopy (SEM) analysis indicated the aggregation of NPs from 10 µg/L to 100 µg/L on surface of A. johnsonii AC15, suggesting that A. johnsonii AC15 acted as the vector for NPs. Exposure to 100−1000 µg/L NPs increased the growth and colony-forming unit (CFU) of A. johnsonii AC15. In addition, exposure to 100−1000 µg/L NPs enhanced the amount of formed biofilm of A. johnsonii AC15. Alterations in expressions of 3 survival-related (zigA, basD, and zur), 5 biofilm formation-related (ompA, bap, adeG, csuC, and csuD), and 3 serum resistance-related virulence genes (lpxC, lpxL, and pbpG) were observed after exposure to 1000 µg/L NPs. Moreover, both CFU and survival rate of A. johnsonii AC15 in normal human serum (NHS) were significantly increased by 1−1000 µg/L NPs, suggesting the enhancement in serum resistance of Acinetobacter pathogen by NPs. In the NHS, expressions of 3 survival-related (zigA, basD, and zur), 9 biofilm formation-related (ompA, bap, adeF, adeG, csuA/B, csuC, csuD, csuE, and hlyD), and 3 serum resistance-related virulence genes (lpxC, lpxL, and pbpG) were affected by 1000 µg/L NPs. Expressions of 1 survival-related (zigA), 5 biofilm formation-related (bap, adeG, csuC, csuD, and csuE), and 3 serum resistance-related virulence genes (lpxC, lpxL, and pbpG) were also altered by 10 µg/L NPs after the addition of NHS. Therefore, exposure to NPs in the range of µg/L has the potential to enhance bacterial virulence by increasing their growth, biofilm formation, and serum resistance.

Effects of multi-walled carbon nanotubes in soil on earthworm growth and reproduction, enzymatic activities, and metabolomics.

Increased production and environmental release of multi-walled carbon nanotubes (MWCNTs) increase soil exposure and potential risk to earthworms. However, MWCNT toxicity to earthworms remains unclear, with some studies identifying negative effects and others negligible effects. In this study, to determine whether exposure to MWCNTs negatively affects earthworms and to elucidate possible mechanisms of toxicity, earthworms were exposed to sublethal soil concentrations of MWCNTs (10, 50, and 100 mg/kg) for 28 days. Earthworm growth and reproduction, activities of cytochrome P450 (CYP) isoforms (1A2, 2C9, and 3A4) and antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), and glutathione-s-transferase (GST)), and metabolomics were determined. Effects of MWCNTs on earthworms depended on exposure concentration. Exposure to MWCNTs did not significantly affect growth and reproduction of individual earthworms. Exposure to 50 mg/kg MWCNTs significantly increased activities of CYP2C9, CYP3A4, SOD, CAT, and GST but clearly reduced levels of L-aspartate, L-asparagine, and glutamine. With exposure to 100 mg/kg MWCNTs, toxic effects on earthworms were observed, with significant inhibition in activities of CYP isoenzymes and SOD, significant reductions in L-aspartate, L-asparagine, glutamine, and tryptophan, and simultaneous accumulations of citrate, isocitrate, fumarate, 2-oxoglutarate, pyruvate, D-galactose, carbamoyl phosphate, formyl anthranilate, hypoxanthine, and xanthine. Results suggest that toxicity of MWCNTs to earthworms is associated with reduced detoxification capacity, excessive oxidative stress, and disturbance of multiple metabolic pathways, including amino acids metabolism, the tricarboxylic acid cycle, pyruvate metabolism, D-galactose metabolism, and purine metabolism. The study provides new insights to better understand and predict the toxicity of MWCNTs in soil.

Ferroelectricity induced double-direction conductance modulation in HfxZr1-xO2capacitors.

The artificial synapses are basic units in the hardware implementation of neuromorphic computing, whose performances should be gradually modulated under external stimuli. The underlying mechanism of the increasing and decreasing device conductance is still unclear in the Hf0.5Zr0.5O2based synapses. In this study, the Hf0.5Zr0.5O2capacitors with different stack orders are fabricated in atomic layer deposition, whose ferroelectric properties are investigated by analyzing the capacitance-voltage and polarization-voltage curves. The enhanced ferroelectricity is found after the rapid thermal annealing treatment for all the TiN/Hf0.5Zr0.5O2/TiN, TiN/HfO2-ZrO2/TiN and TiN/ZrO2-HfO2/TiN devices. In the device with poor ferroelectricity, the conductance gradually decreases under both positive and negative identical pulse schemes, which corresponds to the gradual dissolution process of the conductive filaments established in the initial pulse. For the capacitors with strong ferroelectricity, dual-direction conductance modulation can be observed due to the partial domain switching process, which can emulate the potentiation and depression process of biological synapses.

Risk or Return? The Effect of Face Consciousness Influences on the Career Construction of Chinese Rural Dwellers in Urban Areas.

This research improves our understanding of entrepreneurial intention in the Chinese cultural context. Drawing on career construction theory, we received 408 valid surveys from rural Chinese dwellers and examined the relationships rural Chinese have among "face consciousness," indecisiveness, career adaptability, and entrepreneurial intention. We found that those who are fearful of losing face are less likely to have entrepreneurial intentions, but one's desire to gain face has no significant direct impact on entrepreneurial intention. In addition, face consciousness and an indecisive personality interact to influence career adaptability and, in turn, entrepreneurial intention. In sum, this study supports the career construction perspective on understanding the formation of entrepreneurial intention and offers theoretical, practical, and policy implications for entrepreneurial career counseling and training.

Determination of 52 hidden chemical pesticides in biopesticide products by GC-MS/MS and LC-MS/MS.

Addition of chemical pesticides in biopesticides are expected to be common, due to effect of pest control during plant protection. These hidden chemical pesticides may cause various food safety problems if consumed. The purpose of our study was to develop a method to determine 52 hidden chemical pesticides in three formulation biopesticide products. Optimizations of different parameters, such as the instrument analysis condition for target, the extraction, and the composition of clean-up materials were carried out. The developed method used acetonitrile as an extraction solvent for all biopesticide formulations. The composition of adsorbents was based on QuEChERS, called QuSEL which was a needle filter head, containing PSA, GCB, and MgSO4. Fifty-two chemical pesticides residues were then analyzed by GC-MS/MS and LC-MS/MS. The present results showed good linearity by correlation coefficients of more than 0.99 for all analyses. The LOQ ranged from 5.0 to 20.0 µg kg-1. Recoveries of 32 chemical pesticides ranged from 71.9% to 118.4% at the spiked level of 10, 50, and 100 µg kg-1, and 20 chemical pesticides ranged from 75.3% to 119.8% at the spiked level of 5, 25, and 50 µg kg-1. The developed method was applied for biopesticide products, and 9 samples were positive in 20 samples.

The Harbinger transposon-derived gene PANDA epigenetically coordinates panicle number and grain size in rice.

Transposons significantly contribute to genome fractions in many plants. Although numerous transposon-related mutations have been identified, the evidence regarding transposon-derived genes regulating crop yield and other agronomic traits is very limited. In this study, we characterized a rice Harbinger transposon-derived gene called PANICLE NUMBER AND GRAIN SIZE (PANDA), which epigenetically coordinates panicle number and grain size. Mutation of PANDA caused reduced panicle number but increased grain size in rice, while transgenic plants overexpressing this gene showed the opposite phenotypic change. The PANDA-encoding protein can bind to the core polycomb repressive complex 2 (PRC2) components OsMSI1 and OsFIE2, and regulates the deposition of H3K27me3 in the target genes, thereby epigenetically repressing their expression. Among the target genes, both OsMADS55 and OsEMF1 were negative regulators of panicle number but positive regulators of grain size, partly explaining the involvement of PANDA in balancing panicle number and grain size. Moreover, moderate overexpression of PANDA driven by its own promoter in the indica rice cultivar can increase grain yield. Thus, our findings present a novel insight into the epigenetic control of rice yield traits by a Harbinger transposon-derived gene and provide its potential application for rice yield improvement.

Effects of Microplastics on the Mineral Elements Absorption and Accumulation in Hydroponic Rice Seedlings (Oryza sativa L.).

Environmental pollution caused by microplastics (MPs) have become a non-negligible environmental problem and come into our notice recently. Herein, the nutrient elemental signature (ionome) of rice seedlings exposed to four levels of polyethylene microplastics (PE-MPs), and was analyzed by inductively coupled plasma optical emission spectroscopy (ICP-OES) or mass spectroscopy (ICP-MS) to determine the relationship between ionome and MPs. After 21 days of laboratory exposure, no shoots growth difference has shown among any doses of PE-MPs treatments, however, the roots growth was significantly inhibited after the medium and high doses of PE-MPs treatments. Further analysis showed that PE-MPs treatments could decrease the accumulation of one essential mineral element Mn and some non-essential mineral elements accumulation including As and Cd, while increase the accumulation of one essential mineral elements including Na in rice seedlings. This study is the first to document the variation of the rice seedlings ionome after exposing microplastics.

Biosafety assessment of Acinetobacter strains isolated from the Three Gorges Reservoir region in nematode Caenorhabditis elegans.

Acinetobacter has been frequently detected in backwater areas of the Three Gorges Reservoir (TGR) region. We here employed Caenorhabditis elegans to perform biosafety assessment of Acinetobacter strains isolated from backwater area in the TGR region. Among 21 isolates and 5 reference strains of Acinetobacter, exposure to Acinetobacter strains of AC1, AC15, AC18, AC21, A. baumannii ATCC 19606T, A. junii NH88-14, and A. lwoffii DSM 2403T resulted in significant decrease in locomotion behavior and reduction in lifespan of Caenorhabditis elegans. In nematodes, exposure to Acinetobacter strains of AC1, AC15, AC18, AC21, A. baumannii, A. junii and A. lwoffii also resulted in significant reactive oxygen species (ROS) production. Moreover, exposure to Acinetobacter isolates of AC1, AC15, AC18, and AC21 led to significant increase in expressions of both SOD-3::GFP and some antimicrobial genes (lys-1, spp-12, lys-7, dod-6, spp-1, dod-22, lys-8, and/or F55G11.4) in nematodes. The Acinetobacter isolates of AC1, AC15, AC18, and AC21 had different morphological, biochemical, phylogenetical, and virulence gene properties. Our results suggested that exposure risk of some Acinetobacter strains isolated from the TGR region exists for environmental organisms and human health. In addition, C. elegans is useful to assess biosafety of Acinetobacter isolates from the environment.

Antioxidant Activity and Healthy Benefits of Natural Pigments in Fruits: A Review.

Natural pigments, including carotenoids, flavonoids and anthocyanidins, determine the attractive color of fruits. These natural pigments are essential secondary metabolites, which play multiple roles in the whole life cycle of plants and are characterized by powerful antioxidant activity. After decades of research and development, multiple benefits of these natural pigments to human health have been explored and recognized and have shown bright application prospects in food, medicine, cosmetics and other industries. In this paper, the research progress of natural fruit pigments in recent years was reviewed, including the structural characteristics and classification, distribution in fruits and analysis methods, biosynthetic process, antioxidant capacity and mechanism, bioaccessibility and bioavailability, and health benefits. Overall, this paper summarizes the recent advances in antioxidant activity and other biological functions of natural fruit pigments, which aims to provide guidance for future research.

Tomato calmodulin-like protein SlCML37 is a calcium (Ca2+) sensor that interacts with proteasome maturation factor SlUMP1 and plays a role in tomato fruit chilling stress tolerance.

Calmodulin-like proteins (CMLs), as well as their targets, play significant roles in various key developmental and stress responses in the plant. In tomato (Solanum lycopersicum), there are at least 52 CML genes in its genome. However, most of their functions are not well known, especially in response to cold stress. Here, we investigated SlCML37 biochemical and structural characteristics, including a typical α-helical secondary structure and exposing its hydrophobic regions after binding to Ca2+. Then we certificated that SlCML37 protein could physically interact with SlUMP1 by using yeast two-hybrid, bimolecular florescence complementation (BiFC) and GST pull-down assays. Further analysis showed that SlCML37-transgenic tomato fruit conferred significantly improved tolerance to chilling stress. This study indicates a possible role of calmodulin-like protein-mediated proteasome assemble in the regulation of plant cold response.

Antisense oligonucleotide technology can be used to investigate a circular but not linear RNA-mediated function for its encoded gene locus.

As a class of powerful molecular tool, antisense oligonucleotides (ASOs) are not only broadly used in protein and RNA biology, but also a highly selective therapeutic strategy for many diseases. Although the concept that ASO reagents only reduce expression of the targeted gene in a post-transcriptional manner has long been established, the effect and mechanism of ASO reagents on RNA polymerase II (Pol II) transcription are largely unknown. This raised question is particularly important for the appropriate use of ASOs and the valid interpretation of ASO-mediated experiments. In this study, our results show that linear RNA ASO attenuates transcription of nascent transcripts by inducing premature transcription termination which is combinatorially controlled by Integrator, exosome, and Rat1 in Drosophila. However, circular RNA (circRNA) ASO transfection does not affect transcription activity of the encoded gene. These data suggest that the ASO technique can be applied to study a circRNA-mediated but not linear RNA-mediated function for its encoded gene locus.

Does Practice Enhance Adaptability? The Role of Personality Trait, Supervisor Behavior, and Career Development Training.

Drawing upon career construction theory, we examined the mediating effect of deliberate practice (DP) on career adaptability (CA) and the effects of learning goal orientation (LGO) and supervisor incompetence accusations (SIA) as well as career development training (CDT) on DP. Using data collected from 204 Chinese PhD students in three waves over a period of 2 months, we found that individuals who were inclined to learn new skills and obtain new knowledge were more likely to deliberately practice professional activities in their fields. When a PhD student's professional competence was questioned by his or her supervisor, the student was more prone to negative emotions and would reduce his or her effort in the development of expertise. CDT - contrary to expectations - negatively predicted DP of professional activities. One possible reason is that the participants in this study have strong autonomy so that those who really struggling are participating in training and seeking help and those who with strong professional abilities are not accessing training programs. Moreover, results showed that DP of professional activities significantly promoted PhD students to adapt to their academic circumstances. Implications for career-related practice within the academic domain are provided.

Integrated analysis of phenome, genome, and transcriptome of hybrid rice uncovered multiple heterosis-related loci for yield increase.

Hybrid rice is the dominant form of rice planted in China, and its use has extended worldwide since the 1970s. It offers great yield advantages and has contributed greatly to the world's food security. However, the molecular mechanisms underlying heterosis have remained a mystery. In this study we integrated genetics and omics analyses to determine the candidate genes for yield heterosis in a model two-line rice hybrid system, Liang-you-pei 9 (LYP9) and its parents. Phenomics study revealed that the better parent heterosis (BPH) of yield in hybrid is not ascribed to BPH of all the yield components but is specific to the BPH of spikelet number per panicle (SPP) and paternal parent heterosis (PPH) of effective panicle number (EPN). Genetic analyses then identified multiple quantitative trait loci (QTLs) for these two components. Moreover, a number of differentially expressed genes and alleles in the hybrid were mapped by transcriptome profiling to the QTL regions as possible candidate genes. In parallel, a major QTL for yield heterosis, rice heterosis 8 (RH8), was found to be the DTH8/Ghd8/LHD1 gene. Based on the shared allelic heterozygosity of RH8 in many hybrid rice cultivars, a common mechanism for yield heterosis in the present commercial hybrid rice is proposed.

Induction of substantial myocardial regeneration by an active fraction of the Chinese herb Rosa laevigata Michx.

BACKGROUND: The replacement of lost cardiac tissues by regenerated myocardium would be a therapeutic ideal for myocardial infarction. The objective of this study was therefore to evaluate the ability of an active fraction that was isolated from Rosa laevigata Michx in therapeutic cardiomyogenesis in a myocardial infarction rat model. METHODS: The myocardial infarction animal model was induced by the permanent ligation of the left anterior descending coronary artery in rats. The active fraction, which improves the survival rate and prevents ischemic reperfusion damage, was used to test the therapeutic effect of this fraction on myocardial infarction. RESULTS: The oral administration of the active fraction for 4 weeks could progressively restore the decreased cardiac function due to myocardial infarction. The significantly improved cardiac function was probably attributed to the active fraction-induced myocardial regeneration, which replaced the lost cardiac tissues in the myocardial infarction animals. CONCLUSIONS: The property of this active fraction appears to be entirely novel and may provide a potential therapeutic alternative for myocardial infarction.

Plants and their bioactive compounds with the potential to enhance mechanisms of inherited cardiac regeneration.

This article reviews the current progress and research indications in the application of natural plant compounds with the potential for the treatment of cardiovascular diseases. Our understanding of how to apply natural plant compounds to enhance mechanisms of inherited cardiac regeneration, which is physiologically pertinent to myocyte turnover or minor cardiac repair, for substantial cardiac regeneration to repair pathological heart injuries is discussed. Although significant progress has been made in the application of natural plant compounds for therapy of heart diseases, the understanding or the application of these compounds specifically for enhancing mechanisms of inherited cardiac regeneration for the treatment of cardiovascular diseases is little. Recent recognition of some natural plant compounds that can repair damaged myocardial tissues through enhancing mechanisms of inherited cardiac regeneration has offered an alternative for clinical translation. Application of natural plant compounds, which show the activity of manipulating gene expressions in such a way to enhance mechanisms of inherited cardiac regeneration for cardiac repair, may provide a promising strategy for the reconstruction of damaged cardiac tissues due to cardiovascular diseases.

Integrated analysis of miRNA and mRNA expression profiles in response to Cd exposure in rice seedlings.

BACKGROUND: Independent transcriptome profile analyses of miRNAs or mRNAs under conditions of cadmium (Cd) stress have been widely reported in plants. However, a combined analysis of sRNA sequencing expression data with miRNA target expression data to infer the relative activities of miRNAs that regulate gene expression changes resulting from Cd stress has not been reported in rice. To elucidate the roles played by miRNAs in the regulation of changes in gene expression in response to Cd stress in rice (Oryza sativa L.), we simultaneously characterized changes in the miRNA and mRNA profiles following treatment with Cd. RESULTS: A total of 163 miRNAs and 2,574 mRNAs were identified to be differentially expressed under Cd stress, and the changes in the gene expression profile in the shoot were distinct from those in the root. At the miRNA level, 141 known miRNAs belonging to 48 families, and 39 known miRNAs in 23 families were identified to be differentially expressed in the root and shoot, respectively. In addition, we identified eight new miRNA candidates from the root and five from the shoot that were differentially expressed in response to Cd treatment. For the mRNAs, we identified 1,044 genes in the root and 448 genes in the shoot that were up-regulated, while 572 and 645 genes were down-regulated in the root and shoot, respectively. GO and KEGG enrichment analyses showed that genes encoding secondary, metabolite synthases, signaling molecules, and ABC transporters were significantly enriched in the root, while only ribosomal protein and carotenoid biosynthesis genes were significantly enriched in the shoot. Then 10 known miRNA-mRNA interaction pairs and six new candidate ones, that showed the opposite expression patterns, were identified by aligning our two datasets against online databases and by using the UEA sRNA toolkit respectively. CONCLUSIONS: This study is the first to use high throughput DNA sequencing to simultaneously detect changes in miRNA and mRNA expression patterns in the root and shoot in response to Cd treatment. These integrated high-throughput expression data provide a valuable resource to examine global genome expression changes in response to Cd treatment and how these are regulated by miRNAs.

THIS1 is a putative lipase that regulates tillering, plant height, and spikelet fertility in rice.

Proper branching and successful reproductive growth is of great importance for rice productivity. Substantial progress has been made in uncovering the molecular mechanisms underlying tillering control and spikelet sterility. However, rice tillering is developmentally controlled, and how it is regulated coordinately with reproductive growth remains unclear. This study characterized a rice mutant, the most obvious phenotypes of which are high tillering, reduced height, and infertile spikelets (named this1). Similarly to the high tiller number and dwarf mutants in rice, the increased tiller number of this1 plants is ascribed to the release of tiller bud outgrowth rather than to increased tiller bud formation. In the this1 mutant, however, the accelerated rate of branching was delayed until the stem elongation stage, while other mutants lost the ability to control branching at all developmental stages. The seed-setting rate of this1 was less than half that of the wild type, owing to defects in pollen maturation, anther dehiscence, and flower opening. Histological analyses showed that the mutation in this1 resulted in anisotropic cell expansion and cell division. Using a map-based cloning approach, This1 was found to encode a class III lipase. Homology searches revealed that THIS1 is conserved in both monocots and eudicots, suggesting that it plays fundamental role in regulating branch and spikelet fertility, as well as other aspects of developmental control. The relative change in expression of marker genes highlighted the possibility that This1 is involved in phytohormone signalling pathways, such as those for strigolactone and auxin. Thus, This1 provides joint control between shoot branching and reproductive development.