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A direct-injection straw deep-burial method was proposed to address the issues of insufficient depth and compaction during the process of straw deep burial. Based on the working principle of oblique cutting, an in situ soil-lifting shovel is designed for oblique cutting of soil and in situ lifting of soil, forming a deep burial space for straw. Elaborating on the working principle of the in situ soil-lifting shovel, we analyzed the stress situation of each stage during the operation process and determined the structural parameter values of the in situ soil-lifting shovel. Using the DEM simulation analysis method, the regression orthogonal simulation test is carried out with the soil-opening angle, the soil-lifting angle, and the camber angle of the in situ soil-lifting shovel as the test indicators, and the number of straws deeply buried and the operational resistance as the evaluation indicators. The regression equation and the response surface mathematical model were established to analyze the influence of the interaction of various factors on the operational performance of the in situ soil-lifting shovel. The simulation results showed that the significant order of effect on the number of straws buried deeply and the operational resistance was camber angle > soil-opening angle > soil-lifting angle. After optimization, the structural parameters were soil-opening angle of 17°, soil-lifting angle of 37°, camber angle of 30°, the corresponding number of straw buried was 228.29, and the operating resistance was 2840.45 N. The average value of operational resistance obtained from the field validation test was 3145.95 N, and the error with the simulation results was only 11%. The quantity of straw buried deeply was 90.21%. The straw deep burial experiment further indicates that the operation effect meets the agronomic requirements of straw deep burial. [ABSTRACT FROM AUTHOR]

The objective of this study was to measure the concentrations of three intensity sweeteners (Acesulfame–K, cyclamate and saccharin) in different categories of food available on the Nanjing market, and to investigate whether the Nanjing general population was at risk for exceeding the ADI of sweeteners. A set of 1885 foods was collected and analysed using the National Food Safety Standard procedure in order to establish the concentration levels of the sweeteners. Dietary exposure was estimated using probabilistic modelling software and compared directly with each sweetener's ADI. Consumption data from the China National Nutrition and Health Survey (conducted in 2010-2013) and the actual concentrations of sweeteners in the collected food products were used to perform the intake assessment. The results indicated that Acesulfame-K and cyclamate were commonly used in processed food, and processed nuts, preserved fruit, beverages, and bakery products are the main sources of sweeteners in Nanjing. The estimated exposure of sweeteners in Nanjing was well below the ADIs, as relative intakes at the 95th percentile were 29.7% for saccharin, 79.8% for cyclamate, and 35.9% for Acesulfame-K of the respective ADIs. It was concluded that adults were not at risk of exceeding ADIs for these sweeteners, but the intake of cyclamate at the higher percentiles by children may approach or slightly exceed ADI values. [ABSTRACT FROM AUTHOR]

Background: Nuclear reprogramming reinstates totipotency or pluripotency in somatic cells by changing their gene transcription profile. This technology is widely used in medicine, animal husbandry and other industries. However, certain deficiencies severely restrict the applications of this technology. Results: Using single-embryo RNA-seq, our study provides complete transcriptome blueprints of embryos generated by cumulus cell (CC) donor nuclear transfer (NT), embryos generated by mouse embryonic fibroblast (MEF) donor NT and in vivo embryos at each stage (zygote, 2-cell, 4-cell, 8-cell, morula, and blastocyst). According to the results from further analyses, NT embryos exhibit RNA processing and translation initiation defects during the zygotic genome activation (ZGA) period, and protein kinase activity and protein phosphorylation are defective during blastocyst formation. Two thousand three constant genes are not able to be reprogrammed in CCs and MEFs. Among these constant genes, 136 genes are continuously mis-transcribed throughout all developmental stages. These 136 differential genes may be reprogramming barrier genes (RBGs) and more studies are needed to identify. Conclusions: These embryonic transcriptome blueprints provide new data for further mechanistic studies of somatic nuclear reprogramming. These findings may improve the efficiency of somatic cell nuclear transfer. [ABSTRACT FROM AUTHOR]

Background: Long non-coding RNAs (lncRNAs), a type of epigenetic regulator, are thought to play important roles in embryonic development in mice, and several developmental defects are associated with epigenetic modification disorders. The most dramatic epigenetic reprogramming event occurs during somatic cell nuclear transfer (SCNT) when the expression profile of a differentiated cell is abolished, and a newly embryo-specific expression profile is established. However, the molecular mechanism underlying somatic reprogramming remains unclear, and the dynamics and functions of lncRNAs in this process have not yet been illustrated, resulting in inefficient reprogramming. Results: In this study, 63 single-cell RNA-seq libraries were first generated and sequenced. A total of 7009 mouse polyadenylation lncRNAs (including 5204 novel lncRNAs) were obtained, and a comprehensive analysis of in vivo and SCNT mouse pre-implantation embryo lncRNAs was further performed based on our single-cell RNA sequencing data. Expression profile analysis revealed that lncRNAs were expressed in a developmental stage-specific manner during mouse early-stage embryonic development, whereas a more temporal and spatially specific expression pattern was identified in mouse SCNT embryos with changes in the state of chromatin during somatic cell reprogramming, leading to incomplete zygotic genome activation, oocyte to embryo transition and 2-cell to 4-cell transition. No obvious differences between other stages and mouse NTC or NTM embryos at the same stage were observed. Gene oncology (GO) enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis and weighted gene co-expression network analysis (WGCNA) of lncRNAs and their association with known protein-coding genes suggested that several lncRNAs and their associated with known protein-coding genes might be involved in mouse embryonic development and cell reprogramming. Conclusions: This is a novel report on the expression landscapes of lncRNAs of mouse NT embryos by scRNA-seq analysis. This study will provide insight into the molecular mechanism underlying the involvement of lncRNAs in mouse pre-implantation embryonic development and epigenetic reprogramming in mammalian species after SCNT-based cloning. [ABSTRACT FROM AUTHOR]

This study developed a new method to determine the residues of 13 organophosphorus flame retardants (OPFRs) in drinking water by gas chromatography-tandem mass spectrometry (GC-MS/MS) technique and investigated the chemical distribution in water samples from municipal plants along the Yangtze River in Nanjing. The linear calibration correlation coefficients R2 for all 13 OPFRs were at least 0.998 0. Three levels of spiked test were performed. Most of the recoveries were in the range of 80~120%, and the relative standard deviations (RSDs) for the 13 OPFRs were 2.1~17% (n = 6). Five OPFRs were 100% positively detected in the samples, and 3 OPFRs were positively detected in some samples. The concentrations of detected OPFR in the water ranged from 0.7 to 5780.0 ng L−1. The average concentrations of OPFRs in wet season were higher than those in dry season, and the contaminants mainly originated from the source water in the Yangtze River. The exposure assessments of individual and total OPFRs were investigated. The estimated daily intakes of total OPFRs via ingestion of drinking water reached up to 64.8 and 45.2 ng/kg bw/day in dry and wet season, respectively. This study demonstrates a profile of OPFR distribution in Nanjing municipal water and provides information on human exposure assessment via drinking water in the Nanjing District, China. [ABSTRACT FROM AUTHOR]

Background: The transcription factor Oct4 plays a pivotal role in the pre-implantation development of the mouse embryo. DNA methyltransferase 1 (Dnmt1) maintains the changes in DNA methylation during mammalian early embryonic development. Little is known of the role of Oct4 in DNA methylation in mice. In this study, Kunming white mice were used as an animal model to reveal any correlation between DNA methylation and Oct4 during mammalian embryonic development. Results: The expressions of Dnmt1 and Oct4 were initially studied using real-time PCR. They exhibited different patterns during the pre-implantation stage. Moreover, by using a promoter assay and ChIP analysis, we found that the transcriptional activities of Dnmt1 in mouse NIH/3 T3 cells and CCE cells were regulated by Oct4 through direct binding to the − 554 to − 294 fragment of the upstream regulation element of Dnmt1. The downregulation of Dnmt1 expression and enzyme activity by mouse Oct4 were further confirmed by transfecting Oct4 siRNA into mouse CCE cells. Conclusion: Our results indicate that Oct4 is involved in DNA methylation through the regulation of Dnmt1 transcription, especially during the early stages of mouse pre-implantation embryo development. [ABSTRACT FROM AUTHOR]