[Effects of N, P, and K application rates on distribution of 13C assimilates, starch accumulation in grains and fertilizer utilization of wheat]. / 氮磷钾施用量对小麦旗叶13CåŒåŒ–ç‰©åˆ†é ã€ç±½ç²’æ·€ç²‰ç§¯ç´¯å’Œè‚¥æ–™åˆ©ç”¨çš„å½±å“.

Clarifying the appropriate application rates of N, P, and K fertilizers and the physiological mechanisms of wheat under water-saving recharge irrigation in the North China Plain would provide a theoretical basis for formulating reasonable fertilization plans for high-yield and high-efficiency wheat production. We established four treatments with different amounts of nitrogen (N), phosphorus (P2O5), and potassium (K2O) application: 0, 0, and 0 kg·hm-2 (F0), 180, 75, and 60 kg·hm-2 (F1), 225, 120, and 105 kg·hm-2 (F2), and 270, 165, and 150 kg·hm-2 (F3). During the jointing and anthesis stages of wheat, the relative water content of each treatment in the 0-40 cm soil layer was replenished to 70%, to investigate the differences in wheat flag leaf photosynthetic characteristics, distribution of 13C assimilates, grain starch accumulation, and fertilizer utilization. The results showed that the relative chlorophyll content of flag leaves, photosynthetic and chlorophyll fluorescence parameters, 13C assimilate allocation in each organ, enzyme activities involved in starch synthesis, and starch accumulation in the F1 treatment were significantly higher than that in F0 treatment, which was an important physiological basis for the 20.9% increase in grain yield. The above parameters and yield in the F2 and F3 treatments showed no significant increase compared to F1 treatment, while fertilizer productivity and agronomic efficiency of N, P, and K decreased by 17.5%-58.4% and 12.7%-50.7%, respectively. Therefore, F1 could promote flag leaf photosynthetic assimilate production and grain starch accumulation under water-saving supplementary irrigation conditions, resulting in higher grain yield and fertilizer utilization efficiency.

MCT1-mediated transport of valeric acid promotes porcine preimplantation embryo development by improving mitochondrial function and inhibiting the autophagic AMPK-ULK1 pathway.

Oocytes and embryos are highly sensitive to environmental stress in vivo and in vitro. During in vitro culture, many stressful conditions can affect embryo quality and viability, leading to adverse clinical outcomes such as abortion and congenital abnormalities. In this study, we found that valeric acid (VA) increased the mitochondrial membrane potential and ATP content, decreased the level of reactive oxygen species that the mitochondria generate, and thus improved mitochondrial function during early embryonic development in pigs. VA decreased expression of the autophagy-related factors LC3B and BECLIN1. Interestingly, VA inhibited expression of autophagy-associated phosphorylation-adenosine monophosphate-activated protein kinase (p-AMPK), phosphorylation-UNC-51-like autophagy-activated kinase 1 (p-ULK1, Ser555), and ATG13, which reduced apoptosis. Short-chain fatty acids (SCFAs) can signal through G-protein-coupled receptors on the cell membrane or enter the cell directly through transporters. We further show that the monocarboxylate transporter 1 (MCT1) was necessary for the effects of VA on embryo quality, which provides a new molecular perspective of the pathway by which SCFAs affect embryos. Importantly, VA significantly inhibited the AMPK-ULK1 autophagic signaling pathway through MCT1, decreased apoptosis, increased expression of embryonic pluripotency genes, and improved embryo quality.

ConPep: Prediction of peptide contact maps with pre-trained biological language model and multi-view feature extracting strategy.

The accurate prediction of peptide contact maps remains a challenging task due to the difficulty in obtaining the interactive information between residues on short sequences. To address this challenge, we propose ConPep, a deep learning framework designed for predicting the contact map of peptides based on sequences only. To sufficiently incorporate the sequential semantic information between residues in peptide sequences, we use a pre-trained biological language model and transfer prior knowledge from large scale databases. Additionally, to extract and integrate sequential local information and residue-based global correlations, our model incorporates Bidirectional Gated Recurrent Unit and attention mechanisms. They can obtain multi-view features and thus enhance the accuracy and robustness of our prediction. Comparative results on independent tests demonstrate that our proposed method significantly outperforms state-of-the-art methods even with short peptides. Notably, our method exhibits superior performance at the sequence level, suggesting the robust ability of our model compared with the multiple sequence alignment (MSA) analysis-based methods. We expect it can be meaningful research for facilitating the wide use of our method.

Mechanical and Thermal Properties of Phosphoric Acid Activated Geopolymer Materials Reinforced with Mullite Fibers.

This article investigates several important properties, such as thermal resistance, mechanical properties, and phase evolution, of geopolymer ceramics reinforced with mullite fibers. This particular fiber reinforcing geopolymer composites was prepared from kaolinite and mullite fibers with phosphoric acid as activator. X-ray diffraction (XRD), thermogravimetry and differential scanning calorimetry, Fourier-transform infrared spectroscopy, and scanning electron microscopy were used to determine the phase evolution and strengthening mechanisms. With the addition of mullite fibers, the mechanical properties increased by at least 20%. The optimum flexural strength exceeded 13 MPa. It was found that mullite fibers had desirable interface bonding with this type of geopolymer, promoting both crack deflection and fiber pullout strengthening mechanisms. This was correlated with a significant strengthening effect of the fibers. The linear shrinkage after heat treatment at 1150 °C~1550 °C was investigated and correlated with XRD analyses. The addition of mullite fibers reduced the linear shrinkage significantly up to 1350 °C. The large linear shrinkage above 1450 °C was correlated with the decomposition and melting of the AlPO4 phase.

Determination of lipid profiles of Dezhou donkey meat using an LC-MS-based lipidomics method.

Intramuscular fat (IMF) is an important factor affecting meat quality, but lipid and metabolic profiles of donkey meat remain unclear. The present study was conducted to investigate lipid characteristics in different parts of Dezhou donkey using lipidomics. The results show that IMF was more abundant in longissimus dorsi muscle (LDM) than rump muscle (RM) and hamstring muscle (HM), and mainly composed of triglycerides (TGs) rich in saturated fatty acid (SFAs) and monounsaturated fatty acid (MUFAs). A total of 1143 lipids belonging to 14 subclasses were identified in donkey meat, of which 73 lipids (23 upregulated and 50 downregulated) including glycerolipids (GLs), glycerophospholipids (GPs) and sphingolipids (SPs) were significantly different and are therefore potential biomarkers in LDM versus RM versus HM analyses (variable importance in projection >1, p < 0.05). Notably, 21 TGs upregulated in LDM were rich in MUFAs at sn-1 and SFAs at 2 and 3 positions of TG. Donkey muscle accumulated far more SFAs at the sn-3 position of TG, while more SFAs were present at the sn-1 positions of phosphatidylcholine (PC) and phosphatidylethanolamine (PE), and the percentages of SFAs at the three positions in TG, PC, and PE in the LDM group were much higher. The abundance of MUFAs at the sn-2 positions of TG, PC, and PE was significantly greater than in sn-1 or 3 positions, and the percentages of 18:1n-9 at the sn-1 and 2 position of TGs in LDM were significantly higher than in RM and HM groups. Polyunsaturated fatty acids (e.g.,18:2n-6, 18:3n-3, and 20:4n-6) tended to occur at the sn-1 position in TG, but at the sn-2 position in PC and PE. Significantly differential lipids were mainly enriched in GP, GL, and SP pathways, all considered key pathways for regulating IMF. The results reveal the components, structures and metabolic pathways of lipid molecules in donkey meat, and provide novel insight into the development of donkey meat products and accurate regulation of IMF. PRACTICAL APPLICATION: Intramuscular fat (IMF) is an important factor affecting meat quality, which is directly related to meat flavor, juiciness, and tenderness, but lipid and metabolic profiles of IMF remain unclear. The current results provide basic information for the development of donkey meat products, and broaden our understanding of the regulation of IMF.

Pseudo attP sites in favor of transgene integration and expression in cultured porcine cells identified by Streptomyces phage phiC31 integrase.

Phage PhiC31 integrase integrates attB-containing plasmid into pseudo attP site in eukaryotic genomes in a unidirectional site-specific manner and maintains robust transgene expression. Few studies, however, explore its potential in livestock. This study aims to discover the molecular basis of PhiC31 integrase-mediated site-specific recombination in pig cells. We show that PhiC31 integrase can mediate site-specific transgene integration into the genome of pig kidney PK15 cells. Intramolecular recombination in pig PK15 cell line occurred at maximum frequency of 82% with transiently transfected attB- and attP-containing plasmids. An optimal molar ratio of pCMV-Int to pEGFP-N1-attB at 5:1 was observed for maximum number of cell clones under drug selection. Four candidate pseudo attP sites were identified by TAIL-PCR from those cell clones with single-copy transgene integration. Two of them gave rise to higher integration frequency occurred at 33%. 5' and 3' junction PCR showed that transgene integration mediated by PhiC31 integrase was mono-allelic. Micro- deletion and insertion were observed by sequencing the integration border, indicating that double strand break was induced by the recombination. We then constructed rescue reporter plasmids by ABI-REC cloning of the four pseudo attP sites into pBCPB + plasmid. Transfection of these rescue plasmids and pCMV-Int resulted in expected intramolecular recombination between attB and pseudo attP sites. This proved that the endogenous pseudo attP sites were functional substrates for PhiC31 integrase-mediated site-specific recombination. Two pseudo attP sites maintained robust extracellular and intracellular EGFP expression. Alamar blue assay showed that transgene integration into these specific sites had little effect on cell proliferation. This is the first report to document the potential use of PhiC31 integrase to mediate site-specific recombination in pig cells. Our work established an ideal model to study the position effect of identical transgene located in diverse chromosomal contexts. These findings also form the basis for targeted pig genome engineering and may be used to produce genetically modified pigs for agricultural and biomedical uses.

An asymmetric PCR-based, reliable and rapid single-tube native DNA engineering strategy.

BACKGROUND: Widely used restriction-dependent cloning methods are labour-intensive and time-consuming, while several types of ligase-independent cloning approaches have inherent limitations. A rapid and reliable method of cloning native DNA sequences into desired plasmids are highly desired. RESULTS: This paper introduces ABI-REC, a novel strategy combining asymmetric bridge PCR with intramolecular homologous recombination in bacteria for native DNA cloning. ABI-REC was developed to precisely clone inserts into defined location in a directional manner within recipient plasmids. It featured an asymmetric 3-primer PCR performed in a single tube that could robustly amplify a chimeric insert-plasmid DNA sequence with homologous arms at both ends. Intramolecular homologous recombination occurred to the chimera when it was transformed into E.coli and produced the desired recombinant plasmids with high efficiency and fidelity. It is rapid, and does not involve any operational nucleotides. We proved the reliability of ABI-REC using a double-resistance reporter assay, and investigated the effects of homology and insert length upon its efficiency. We found that 15 bp homology was sufficient to initiate recombination, while 25 bp homology had the highest cloning efficiency. Inserts up to 4 kb in size could be cloned by this method. The utility and advantages of ABI-REC were demonstrated through a series of pig myostatin (MSTN) promoter and terminator reporter plasmids, whose transcriptional activity was assessed in mammalian cells. We finally used ABI-REC to construct a pig MSTN promoter-terminator cassette reporter and showed that it could work coordinately to express EGFP. CONCLUSIONS: ABI-REC has the following advantages: (i) rapid and highly efficient; (ii) native DNA cloning without introduction of extra bases; (iii) restriction-free; (iv) easy positioning of directional and site-specific recombination owing to formulated primer design. ABI-REC is a novel approach to DNA engineering and gene functional analysis.

Cloning and analysis of IFRG (interferon responsive gene) in rabbit oocytes and preimplantation embryos.

Although there is more evidence that shows that IFNs (interferons) plays a very important role in the early development of the embryo, the mechanism of IFNs is still unclear. Our study showed that IFRG is expressed from oocytes- through to the preimplantation embryo in rabbits. This finding provides some clues for better understanding the role of IFNs in the development of the embryo. The full length of rabbit IFRG cDNA (Accession No. AJ584672), with a 2794bp encoding 131 amino acid sequence, was cloned IFRG expression can be detected in 8 different tissues: ovary, heart, lung, liver, kidney, spleen, cerebra, and the 18-day whole-body embryo. Whole-mount in situ hybridization showed that IFRG was highly expressed in the inner-cell mass of rabbit blastula. IFRG may play an important role in embryo development and tissue differentiation.

[Coexpression of human complement regulatory protein genes, CD59 and MCP in transgenic mice protects isolated mouse heart function in ex vivo human plasma perfusion model].

OBJECTIVE: To investigate if the expression of human complement regulatory protein genes in transgenic donor protects against hyperacute rejection (HAR) in the recipient. METHODS: Kunming mice were transfected with 2 human complement regulatory protein genes, CD59 and MCP, so as to establish a transgenic hCD59/hMCP mouse model. Eight hCD59 expression mice, 11 hMCP expression mice, and 8 hCD59/hMCP expression mice were used as experimental groups, and 10 transgenic negative littermates were used as control group. The hearts of the mice were taken out to be perfused with 10% pooled human blood of B type. During the perfusion electrocardiography was carried out to observe the beating time. After the hearts stopped beating, immunofluorescence staining and immunohistochemistry were used to detect the deposition of complements C(9) and C(3c) in the heart tissue. RESULTS: The mean heart beating time was 138 +/- 25 minutes in the hCD59/hMCP expression group, 78 +/- 27 minutes in the hCD59 expression group, 43 +/- 21 minutes in the hMCP group, and 20 +/- 12 minutes in the wild type nontransgenic control group (all P < 0.01, Dennett's T test for all 3 other groups relative to the hCD59/hMCP group). Deposition of the complement C(9) and that of C(3c) were not found in the hearts of the hCD59/hMCP group, however, could be found in the hearts of the 2 monotransgenic groups and nontransgenic group. CONCLUSION: The coexpression of human complement regulatory protein genes, CD59 and MCP in the xenografts effectively inhibits the complement of xenograft-mediated HAR.

[Establishment of a new method for early embryo culture in vitro].

A new method, nest culture method, was developed in this study. The culture effects of different methods for embryo culture in vitro were compared. The results showed that whether the suspension in phi35mm dish in nest culture method was covered with mineral oil or not, the developmental rates of embryos had no significant difference. Compared to the nest culture method, the developmental rates of embryos in Brinster's method were significant lower. However, all embryos cultured in the single dish in which the suspensions were not covered with mineral oil were blocked at 2-cell stage. The nest culture method is an effective method for early embryo culture in vitro.