Environmental and Climatic Drivers of Phytoplankton Communities in Central Asia.

Artificial water bodies in Central Asia offer unique environments in which to study plankton diversity influenced by topographic barriers. However, the complexity of these ecosystems and limited comprehensive studies in the region challenge our understanding. In this study, we systematically investigated the water environment parameters and phytoplankton community structure by surveying 14 artificial waters on the southern side of the Altai Mountains and the northern and southern sides of the Tianshan Mountains in the Xinjiang region. The survey covered physical and nutrient indicators, and the results showed noticeable spatial differences between waters in different regions. The temperature, dissolved oxygen, total nitrogen, and total phosphorus of artificial water in the southern Altai Mountains vary greatly. In contrast, the waters in the northern Tianshan Mountains have more consistent physical indicators. The results of phytoplankton identification showed that the phytoplankton communities in different regions are somewhat different, with diatom species being the dominant taxon. The cluster analysis and the non-metric multidimensional scaling (NMDS) results also confirmed the variability of the phytoplankton communities in the areas. The variance partitioning analysis (VPA) results showed that climatic and environmental factors can explain some of the variability of the observed data. Nevertheless, the residual values indicated the presence of other unmeasured factors or the influence of stochasticity. This study provides a scientific basis for regional water resource management and environmental protection.

Molecular and physiological responses of two quinoa genotypes to drought stress.

Quinoa is an important economic food crop. However, quinoa seedlings are susceptible to drought stress, and the molecular mechanism of drought tolerance remains unclear. In this study, we compared transcriptomic and physiological analyses of drought-tolerant (L1) and susceptible (HZ1) genotypes exposed to 20% PEG for 3 and 9 days at seedling stage. Compared with HZ1, drought stress had less damage to photosynthetic system, and the contents of SOD, POD and CAT were higher and the contents of H2O2 and O2 -were lower in L1 leaves. Based on the RNA-seq method, we identified 2423, 11856, 1138 and 3903 (HZ1-C3-VS-T3, HZ1-C9-vs-T9, L1-C3-vs-T3 and L1-C9-vs-T9) annotated DEGs. Go enrichment was shown in terms of Biological Process: DEGs involved in biological processes such as metabolic process, cellular process, and single-organism process were most abundant in all four comparison treatments. In Molecular Function: the molecular functions of catalytic activity, binding and transporter activity have the most DEGs in all four processes. Cellular Component: membrane, membrane part, and cell have the most DEGs in each of the four processes. These DEGs include AP2/ERF, MYB, bHLH, b-ZIP, WRKY, HD-ZIP, NAC, C3h and MADS, which encode transcription factors. In addition, the MAPK pathway, starch and sucrose metabolism, phenylpropanoid biosynthesis and plant hormone signal transduction were significantly induced under drought stress, among them, G-hydrolases-66, G-hydrolases-81, G-hydrolases-78, Su-synthase-02, Su-synthase-04, Su-synthase-06, BRI1-20 and bHLH17 were all downregulated at two drought stress points in two genotypes, PP2C01, PP2C03, PP2C05-PP2C07, PP2C10, F-box01 and F-box02 were upregulated at two drought stress points in two genotypes. These results agree with the physiological responses and RNA-seq results. Collectively, these findings may lead to a better understanding of drought tolerance, and some of the important DEGs detected in this study could be targeted for future research. And our results will provide a comprehensive basis for the molecular network that mediates drought tolerance in quinoa seedlings and promote the breeding of drought-resistant quinoa varieties.

Regulation of endogenous hormone and miRNA in leaves of alfalfa (Medicago sativa L.) seedlings under drought stress by endogenous nitric oxide.

BACKGROUND: Alfalfa (Medicago sativa. L) is one of the best leguminous herbage in China and even in the world, with high nutritional and ecological value. However, one of the drawbacks of alfalfa is its sensitivity to dry conditions, which is a global agricultural problem. The objective of this study was to investigate the regulatory effects of endogenous nitric oxide (NO) on endogenous hormones and related miRNAs in alfalfa seedling leaves under drought stress. The effects of endogenous NO on endogenous hormones such as ABA, GA3, SA, and IAA in alfalfa leaves under drought stress were studied. In addition, high-throughput sequencing technology was used to identify drought-related miRNAs and endogenous NO-responsive miRNAs in alfalfa seedling leaves under drought stress. RESULT: By measuring the contents of four endogenous hormones in alfalfa leaves, it was found that endogenous NO could regulate plant growth and stress resistance by inducing the metabolism levels of IAA, ABA, GA3, and SA in alfalfa, especially ABA and SA in alfalfa. In addition, small RNA sequencing technology and bioinformatics methods were used to analyze endogenous NO-responsive miRNAs under drought stress. It was found that most miRNAs were enriched in biological pathways and molecular functions related to hormones (ABA, ETH, and JA), phenylpropane metabolism, and plant stress tolerance. CONCLUSION: In this study, the analysis of endogenous hormone signals and miRNAs in alfalfa leaves under PEG and PEG + cPTIO conditions provided an important basis for endogenous NO to improve the drought resistance of alfalfa at the physiological and molecular levels. It has important scientific value and practical significance for endogenous NO to improve plant drought resistance.

Ecology of Saline Watersheds: An Investigation of the Functional Communities and Drivers of Benthic Fauna in Typical Water Bodies of the Irtysh River Basin.

In this study, we investigated how changes in salinity affect biodiversity and function in 11 typical water bodies in the Altai region. The salinity of the freshwater bodies ranged from 0 to 5, the brackish water salinities ranged from 5 to 20, and the hypersaline environments had salinities > 20. We identified 11 orders, 34 families, and 55 genera in 3061 benthic samples and classified them into 10 traits and 32 categories. Subsequently, we conducted Mantel tests and canonical correlation analysis (CCA) and calculated biodiversity and functional diversity indices for each sampling site. The results indicated that biodiversity and the proportion of functional traits were greater in freshwater environments than in saline environments and decreased gradually with increasing salinity. Noticeable shifts in species distribution were observed in high-salinity environments and were accompanied by specific functional traits such as swimming ability, smaller body sizes, and air-breathing adaptations. The diversity indices revealed that the species were more evenly distributed in high-diversity environments under the influence of salinity. In contrast, in high-salinity environments, only a few species dominated. The results suggested that increasing salinity accelerated the evolution of benthic communities, leading to reduced species diversity and functional homogenization. We recommend enhancing the monitoring of saline water resources and implementing sustainable water resource management to mitigate the impact of salinity stress on aquatic communities in response to climate-induced soil and water salinization.

Assessing the Impact of Anthropic Pressures on Aquatic Macroinvertebrates: A Functional Trait Approach in the Irtysh River Watershed.

Little is known about how changes in the biodiversity and functional traits of macroinvertebrates in rivers respond to the responses of anthropic pressures and their driving factors. Macroinvertebrates were sampled at 17 sites in the Irtysh River Basin and classified macroinvertebrates into 10 traits and 38 categories between May and August 2022. Then, we performed R-mode linked to Q-mode (RLQ) analysis and calculated functional richness, evenness, divergence, and Rao's quadratic entropy (RaoQ) for each site and community-weighted means for each trait category. Our results indicated that there were pronounced alterations in species variability in the urban region. Functional divergence indicated fierce competition among species and considerable niche overlap in the urban region. Functional evenness indicated that species abundance distribution and interspecific functional distance were not uniform in the urban region. Functional richness indicated that the urban region was the strongest region in terms of niche occupation, resource utilization, and buffering capacity for environmental fluctuations. Rao's quadratic entropy showed that the trait difference of macroinvertebrates was the largest in all regions, which was caused by the gradient environmental difference. Research has revealed that urbanization significantly influences the evolutionary trajectory of macroinvertebrate fauna, culminating in an upsurge in pollution-tolerant species and a convergence of functional traits. We recommend strengthening the control of urban and industrial pollution and wise planning and management of land and water resources to mitigate the impact of anthropogenic destruction on habitat fragmentation in the Irtysh River Basin.

Non-targeted metabolomics analysis of metabolite changes in two quinoa genotypes under drought stress.

BACKGROUND: Quinoa is an important economic crop, drought is one of the key factors affecting quinoa yield. Clarifying the adaptation strategy of quinoa to drought is conducive to cultivating drought-tolerant varieties. At present, the study of quinoa on drought stress-related metabolism and the identification of related metabolites are still unknown. As a direct feature of biochemical functions, metabolites can reveal the biochemical pathways involved in drought response. RESULT: Here, we studied the physiological and metabolic responses of drought-tolerant genotype L1 and sensitive genotype HZ1. Under drought conditions, L1 had higher osmotic adjustment ability and stronger root activity than HZ1, and the relative water content of L1 was also higher than that of HZ1. In addition, the barrier-to- sea ratio of L1 is significantly higher than that of HZ1. Using untargeted metabolic analysis, a total of 523, 406, 301 and 272 differential metabolites were identified in L1 and HZ1 on day 3 and day 9 of drought stress. The key metabolites (amino acids, nucleotides, peptides, organic acids, lipids and carbohydrates) accumulated differently in quinoa leaves. and HZ1 had the most DEMs in Glycerophospholipid metabolism (ko00564) and ABC transporters (ko02010) pathways. CONCLUSION: These results provide a reference for characterizing the response mechanism of quinoa to drought and improving the drought tolerance of quinoa.

Genome-wide analysis of AP2/ERF gene and functional analysis of CqERF24 gene in drought stress in quinoa.

Quinoa is a crop with high nutritional value and strong stress resistance. AP2/ERF transcription factors play a key role in plant growth and development. In this study, 148 AP2/ERF genes were identified in quinoa, which were divided into 5 subfamilies, including ERF, AP2, DREB, RAV and Soloist. The results showed that the number of introns ranged from 0 to 11, and the Motif 1-Motif 4 was highly conserved in most CqAP2/ERF proteins. The 148 CqAP2/ERF genes were distributed on 19 chromosomes. There were 93 pairs of duplicating genes in this family, and gene duplication played a critical role in the expansion of this family. Protein-protein interaction indicated that the proteins in CqAP2/ERF subfamily exhibited complex interactions, and GO enrichment analysis indicated that 148 CqAP2/ERF proteins were involved in transcription factor activity. In addition, CqAP2/ERF gene contains a large number of elements related to hormones in promoter region (IAA, GA, SA, ABA and MeJA) and stresses (salt, drought, low temperature and anaerobic induction). Transcriptome analysis under drought stress indicated that most of the CqAP2/ERF genes were responsive to drought stress, and subcellular localization indicated that CqERF24 was location in the nucleus, qRT-PCR results also showed that most of the genes such as CqERF15, CqERF24, CqDREB03, CqDREB14, CqDREB37 and CqDREB43 also responded to drought stress in roots and leaves. Overexpression of CqERF24 in Arabidopsis thaliana enhanced drought resistance by increasing antioxidant enzyme activity and activation-related stress genes, and the gene is sensitive to ABA, while silencing CqERF24 in quinoa decreased drought tolerance. In addition, overexpression of CqERF24 in quinoa calli enhanced resistance to mannitol. These results lay a solid foundation for further study on the role of AP2/ERF family genes in quinoa under drought stress.

Multi-omics analysis reveals hepatic lipid metabolism profiles and serum lipid biomarkers upon indoor relevant VOC exposure.

As a widespread indoor air pollutant, volatile organic compound (VOC) caused various adverse health effects, especial the damage to liver, which has become a growing public concern. However, the current toxic data are intrinsically restricted in the single or major VOC species. Limited knowledge is available regarding toxic effects, biomarkers and underlying mechanisms of real indoor VOC-caused liver damage. Herein, an indoor relevant VOC exposure model was established to evaluate the hepatic adverse outcomes. Machine learning and multi-omics approaches, including liver lipidomic, serum lipidomic and liver transcriptomic, were utilized to uncover the characteristics of liver damage, serum lipid biomarkers, and involved mechanism stimulated by VOC exposure. The result showed that indoor relevant VOC led to the abnormal hepatic lipid metabolism, mainly manifested as a decrease in triacylglycerol (TG) and its precursor substance diacylglycerol (DG), which could be contributed to the occurrence of hepatic adverse outcomes. In terms of serum lipid biomarkers, five lipid biomarkers in serum were uncovered using machine learning to reflect the hepatic lipid disorders induced by VOC. Multi-omics approaches revealed that the upregulated Dgkq disturbed the interconversion of DG and phosphatidic acid (PA), leading to a TG downregulation. The in-depth analysis revealed that VOC down-regulated FoxO transcription factor, contributing to the upregulation of Dgkq. Hence, this study can provide valuable insights into the understanding of liver damage caused by indoor relevant VOC exposure model VOC exposure, from the perspective of multi-omics analysis.

Identification of CDK gene family and functional analysis of CqCDK15 under drought and salt stress in quinoa.

as one of the oldest cultivated crops in the world, quinoa has been widely valued for its rich nutritional value and green health. In this study, 22 CDK genes (CqCDK01-CqCDK22) were identified from quinoa genome using bioinformatics method. The number of amino acids was 173-811, the molecular weight was 19,554.89 Da-91,375.70 Da, and the isoelectric point was 4.57-9.77. The phylogenetic tree divided 21 CqCDK genes into six subfamilies, the gene structure showed that 12 (54.5%) CqCDK genes (CqCDK03, CqCDK04, CqCDK05, CqCDK06, CqCDK07, CqCDK11, CqCDK14, CqCDK16, CqCDK18, CqCDK19, CqCDK20 and CqCDK21) had UTR regions at 5' and 3' ends. Each CDK protein had different motifs (3-9 motifs), but the genes with the same motifs were located in the same branch. Promoter analysis revealed 41 cis-regulatory elements related to plant hormones, abiotic stresses, tissue-specific expression and photoresponse. The results of real-time fluorescence quantitative analysis showed that the expression level of some CDK genes was higher under drought and salt stress, which indicated that CDK genes could help plants to resist adverse environmental effects. Subcellular localization showed that CqCDK15 gene was localized to the nucleus and cytoplasm, and transgenic plants overexpressing CqCDK15 gene showed higher drought and salt tolerance compared to the controls. Therefore, CDK genes are closely related to quinoa stress resistance. In this study, the main functions of quinoa CDK gene family and its expression level in different tissues and organs were analyzed in detail, which provided some theoretical support for quinoa stress-resistant breeding. Meanwhile, this study has important implications for further understanding the function of the CDK gene family in quinoa and our understanding of the CDK family in vascular plant.

Identification of Alfalfa SPL gene family and expression analysis under biotic and abiotic stresses.

The SQUAMOSA promoter binding-like protein (SPL) is a specific transcription factor that affects plant growth and development. The SPL gene family has been explored in various plants, but information about these genes in alfalfa is limited. This study, based on the whole genome data of alfalfa SPL, the fundamental physicochemical properties, phylogenetic evolution, gene structure, cis-acting elements, and gene expression of members of the MsSPL gene family were analyzed by bioinformatics methods. We identified 82 SPL sequences in the alfalfa, which were annotated into 23 genes, including 7 (30.43%) genes with four alleles, 10 (43.47%) with three, 3 (13.04%) with two, 3 (13.04%) with one allele. These SPL genes were divided into six groups, that are constructed from A. thaliana, M. truncatula and alfalfa. Chromosomal localization of the identified SPL genes showed arbitary distribution. The subcellular localization predictions showed that all MsSPL proteins were located in the nucleus. A total of 71 pairs of duplicated genes were identified, and segmental duplication mainly contributed to the expansion of the MsSPL gene family. Analysis of the Ka/Ks ratios indicated that paralogs of the MsSPL gene family principally underwent purifying selection. Protein-protein interaction analysis of MsSPL proteins were performed to predict their roles in potential regulatory networks. Twelve cis-acting elements including phytohormone and stress elements were detected in the regions of MsSPL genes. We further analyzed that the MsSPLs had apparent responses to abiotic stresses such as drought and salt and the biotic stress of methyl jasmonate. These results provide comprehensive information on the MsSPL gene family in alfalfa and lay a solid foundation for elucidating the biological functions of MsSPLs. This study also provides valuable on the regulation mechanism and function of MsSPLs in response to biotic and abiotic stresses.

Genome-wide identification and expression pattern analysis of quinoa BBX family.

BBX is a transcription factor encoding zinc finger protein that plays a key role in plant growth and development as well as in responding to abiotic stresses. However, in quinoa, which is known as a "super grain" and has extremely high nutritional value, this gene family has not yet been thoroughly studied. In this study, in order to fully understand the family function of the BBX in quinoa, a total of 31 BBX members were identified by bioinformatics methods. These BBX members were mainly acidic proteins, and most of their secondary structures were random coil s, 31 CqBBX members were unevenly distributed on 17 chromosomes, and the analysis of replication events found that quinoa BBX genes produced a total of 14 pairs of gene replication. The BBX genes were divided into five subfamilies according to phylogenetics, and its gene structure and conserved motif were basically consistent with the classification of its phylogenetic tree. In addition, a total of 43 light response elements, hormone response elements, tissue-specific expression response elements, and abiotic stress response elements were found in the promoter region, involving stress elements such as drought and low temperature. Finally, the expression patterns of CqBBX genes in different tissues and abiotic stresses were studied by combining transcriptome data and qRT-PCR , and all 13 genes responded to drought, salt, and low-temperature stress to varying degrees. This study is the first comprehensive study of the BBX family of quinoa, and its results provide important clues for further analysis of the function of the abiotic stress response.

Genome-wide identification, phylogenetic, and expression analysis under abiotic stress conditions of Whirly (WHY) gene family in Medicago sativa L.

The WHY family is a group of plant-specific transcription factors, that can bind to single-stranded DNA molecules and play a variety of functions in plant nuclei and organelles, participating in the regulation of plant leaf senescence. It has been identified and analyzed in many species, however, the systematic identification and analysis of the WHY genes family have not yet been reported in alfalfa (Medicago sativa L.). Therefore, to explore the function of alfalfa the WHY genes, and 10 MsWHY genes were identified and further characterized their evolutionary relationship and expression patterns by analyzing the recently published genome of alfalfa. Comprehensive analysis of the chromosome location, physicochemical properties of the protein, evolutionary relationship, conserved motifs, and responses to abiotic stresses of the WHY gene family in alfalfa using bioinformatics methods. The results showed that 10 MsWHY genes were distributed on 10 chromosomes, and collinearity analysis showed that many MsWHYs might be derived from segmental duplications, and these genes are under purifying selection. Based on phylogenetic analyses, the WHY gene family of alfalfa can be divided into four subfamilies: I-IV subfamily, and approximately all the WHY genes within the same subfamily share similar gene structures. The 10 MsWHY gene family members contained 10 motifs, of which motif 2 and motif 4 are the conserved motifs shared by these genes. Furthermore, the analysis of cis-regulatory elements indicated that regulatory elements related to transcription, cell cycle, development, hormone, and stress response are abundant in the promoter sequence of the MsWHY genes. Real-time quantitative PCR demonstrated that MsWHYs gene expression is induced by drought, salt, and methyl jasmonate. The present study serves as a basic foundation for future functional studies on the alfalfa WHY family.

Exogenous Nitric Oxide Alleviates the Damage Caused by Tomato Yellow Leaf Curl Virus in Tomato through Regulation of Peptidase Inhibitor Genes.

The tomato yellow leaf curl virus (TYLCV) is the causal agent of one of the most severe diseases affecting tomato growth; however, nitric oxide (NO) can mediate plant resistance. This study investigated the molecular mechanism of exogenous NO donor-mediated disease resistance in tomato seedlings. Tomato seedlings were treated with sodium nitroprusside and TYLCV and subjected to phenotypic, transcriptomic, and physiological analyses. The results show that exogenous NO significantly reduced disease index, MDA content, and virus content (71.4%), significantly increased stem length and fresh weight of diseased plants (p < 0.05), and improved photosynthesis with an induction effect of up to 44.0%. In this study, it was found that the reduction in virus content caused by the increased expression of peptidase inhibitor genes was the main reason for the increased resistance in tomatoes. The peptidase inhibitor inhibited protease activity and restrained virus synthesis, while the significant reduction in virus content inevitably caused a partial weakening or shutdown of the disease response process in the diseased plant. In addition, exogenous NO also induces superoxide dismutase, peroxidase activity, fatty acid elongation, resistance protein, lignin, and monoterpene synthesis to improve resistance. In summary, exogenous NO enhances resistance in tomatoes mainly by regulating peptidase inhibitor genes.

Prediction Model of Soil Heavy Metal Content Based on Particle Swarm Algorithm Optimized Neural Network.

In 2014, the relevant research data from the Ministry of Environmental Protection and the Ministry of Land and Resources showed that the total exceedance rate of soil heavy metal pollution in China had reached 16.1%, and in the construction of ecological civilization in the 13th Five-Year Plan, China has made the prevention and control of soil heavy metal pollution as the focus of prevention and control. Therefore, in this paper, four neural optimization network models, that is, radial basis neural network (RBFNN), generalized regression neural network (GRNN), wavelet neural network (WNN), and fuzzy neural network (FNN), are simulated and created to measure and correlate the soil heavy metal content in a city in northwest China and a city in central China from the actual situation in China. The simulations were conducted. Finally, by analyzing the comparison of predicted and true values of these four models on the test data of two sets of experimental data, the distribution of predicted differences to true values, and the calculation results of three error indicators, we found that WNN has the best prediction performance when using RBFNN, GRNN, WNN, and FNN for soil heavy metal content prediction.

Characterization of the CqCAMTA gene family reveals the role of CqCAMTA03 in drought tolerance.

BACKGROUND: Calmodulin-binding transcription activators (CAMTAs) are relatively conserved calmodulin-binding transcription factors widely found in eukaryotes and play important roles in plant growth and stress response. CAMTA transcription factors have been identified in several plant species, but the family members and functions have not yet been identified and analyzed in quinoa. RESULTS: In this study, we identified seven CAMTA genes across the whole quinoa genome and analyzed the expression patterns of CqCAMTAs in root and leaf tissues. Gene structure, protein domain, and phylogenetic analyses showed that the quinoa CAMTAs were structurally similar and clustered into the same three major groups as other plant CAMTAs. A large number of stress response-related cis-elements existed in the 2 kb promoter region upstream of the transcription start site of the CqCAMTA genes. qRT-PCR indicated that CqCAMTA genes were expressed differentially under PEG treatments in leaves, and responded to drought stress in leaves and roots. In particular, the CqCAMTA03 gene strongly responded to drought. The transient expression of CqCAMTA03-GFP fusion protein in the tobacco leaf showed that CqCAMTA03 was localized in the nucleus. In addition, transgenic Arabidopsis lines exhibited higher concentration levels of the antioxidant enzymes measured, including POD, SOD, and CAT, under drought conditions with very low levels of H2O2 and MDA. Moreover, relative water content and the degree of stomatal opening showed that the transgenic Arabidopsis lines were more tolerant of both stress factors as compared to their wild types. CONCLUSION: In this study, the structures and functions of the CAMTA family in quinoa were systematically explored. Many CAMTAs may play vital roles in the regulation of organ development, growth, and responses to drought stress. The results of the present study serve as a basis for future functional studies on the quinoa CAMTA family.

Genome-wide identification, structural analysis and expression profiles of short internodes related sequence gene family in quinoa.

Based on the whole genome data information of Chenopodium quinoa Willd, the CqSRS gene family members were systematically identified and analyzed by bioinformatics methods, and the responses of CqSRS genes to NaCl (100 mmol/L), salicylic acid (200 umol/L) and low temperature (4°C) were detected by qRT-PCR. The results showed that a total of 10 SHI related sequence genes were identified in quinoa, and they were distributed on 9 chromosomes, and there were four pairs of duplicated genes. The number of amino acids encoded ranged from 143 aa to 370 aa, and the isoelectric point ranged from 4.81 to 8.90. The secondary structure was mainly composed of random coil (Cc). Most of the SRS gene encoding proteins were located in the cytoplasm (5 CqSRS). Phylogenetic analysis showed that the CqSRS genes were divided into three groups, and the gene structure showed that the number of exons of CqSRS was between two-five. Promoter analysis revealed that there are a total of 44 elements related to plant hormone response elements, light response elements, stress response elements and tissue-specific expression in the upstream regin of the gene. Protein interaction showed that all 10 CqSRS proteins appeared in the known protein interaction network diagram in Arabidopsis. Expression profile analysis showed that CqSRS genes had different expression patterns, and some genes had tissue-specific expression. qRT-PCR showed that all SRS family genes responded to ABA、NaCl、drought and low-temperature treatments, but the expression levels of different CqSRS genes were significantly different under various stresses. This study lays a foundation for further analyzed the function of CqSRS genes.

Transcriptome analysis reveals the main metabolic pathway of c-GMP induced by salt stress in tomato (Solanum lycopersicum) seedlings.

Tomato (Solanum lycopersicum L.) is a model crop as well as an important food worldwide. In arid areas, increasing soil salinity has limited higher yields in tomato production. As a second messenger molecule, cyclic guanosine monophosphate (c-GMP) plays an indispensable role in plant response to salt stress by regulating cell processes to promote plant growth and development. However, this mechanism has not been fully explored in tomato seedlings. In this experiment, tomato seeds were cultured in four treatments: (1) distilled water (CK); (2) 20µM c-GMP (T1); (3) 50mM NaCl (T2); and (4) 20µM c-GMP+50mM NaCl (T3). The results show that 20µM c-GMP effectively alleviated the inhibitory effect of 50mM NaCl on growth and development, and induced the expression of 1580 differentially expressed genes (DEGs). Seedlings in the CK vs T1 shared 95 upregulated and 442 downregulated DEGs, whereas T2 vs T3 shared 271 upregulated and 772 downregulated DEGs. Based on KEGG (Kyoto Encyclopaedia of Genes and Genomes) analysis, the majority of DEGs were involved in metabolism; exogenous c-GMP induced significant enrichment of pathways associated with carbohydrates, phenylpropanoids and fatty acid metabolism. Most PMEs , acCoA , PAL , PODs , FADs , and AD were upregulated, and GAPDHs , PL , PG , BXL4 , and ß-G were downregulated, which reduced susceptibility of tomato seedlings to salt and promoted their salt tolerance. The application of c-GMP increased soluble sugar, flavonoid and lignin contents, reduced accumulation of malondialdehyde (MDA), and enhanced the activity of peroxidase (POD). Thus, our results provide insights into the molecular mechanisms associated with salt tolerance of tomato seedlings.

The Foam Cell Formation Associated With Imbalanced Cholesterol Homeostasis Due to Airborne Magnetite Nanoparticles Exposure.

Fine particulate matter (PM) is a leading environmental cause for the increased morbidity and mortality of atherosclerosis (AS) worldwide, but little is known about the toxic component and disturbance of PM exposure on foam cell formation, a crucial pathological process in AS. Airborne magnetite nanoparticles (NPs) have been reported to be detected in human serum, which inevitably encounter with macrophages in atherosclerotic plaques, thus throwing potential disturbance on the formation of macrophage-derived foam cells. Here we comprehensively unveiled that the environmental concentrations of PM exposure triggered and potentiated the formation of macrophage-derived foam cells using both real-ambient PM-exposed mice and AS mice models, including high-fat diet-fed mice and apolipoprotein E-deficient mice. The in vitro model further defined the dose-dependent response of PM treatment on foam cell formation. Interestingly, airborne magnetite NPs rather than nonmagnetic NPs at the same concentration were demonstrated to be the key toxic component of PM in the promoted foam cell formation. Furthermore, magnetite NPs exposure led to abnormal cholesterol accumulation in macrophages, which was attributed to the attenuation of cholesterol efflux and enhancement of lipoprotein uptake, but independent of cholesterol esterification. The in-depth data revealed that magnetite NPs accelerated the protein ubiquitination and subsequent degradation of SR-B1, a crucial transporter of cholesterol efflux. Collectively, these findings for the first time identified magnetite NPs as one key toxic component of PM-promoted foam cell formation, and provided new insight of abnormal cholesterol metabolism into the pathogenesis of PM-induced AS.

Membrane cleaning in membrane distillation of reverse osmosis concentrate generated in landfill leachate treatment.

As a thermally induced membrane separation process, membrane distillation (MD) has drawn more and more attention to the advantages of treating hypersaline wastewaters, especially the concentrate from the reverse osmosis (RO) process. One of the major obstacles in widespread MD application is the membrane fouling. We investigated the feasibility of direct contact membrane distillation (DCMD) for landfill leachate reverse osmosis concentrate (LFLRO) brine treatment and systematically assessed the efficiency of chemical cleaning for DCMD after processing LFLRO brine. The results showed that 80% water recovery rate was achieved when processing the LFLRO brine by DCMD, but membrane fouling occurred during the DCMD process, and manifested as the decreasing of permeate flux and the increasing of permeate conductivity. Analysis revealed that the serious flux reduction was primarily caused by the fouling layer, which consisted of organic matter and inorganic salts. Five cleaning methods were investigated for membrane cleaning, including hydrogen chloride (HCl)-sodium hydroxide (NaOH), ethylene diamine tetraacetic acid (EDTA)-NaOH, citric acid, sodium hypochlorite (NaClO) and sodium dodecyl sulphate (SDS) cleaning. Among the chemical cleaning methods investigated, the 3 wt.% SDS cleaning showed the best efficiency at recovering the performance of fouled membranes.