Latest Issue
Issue 7 ， 2021
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How silicon fertilizer improves nitrogen and phosphorus nutrient availability in paddy soil?
Abstract：In order to reveal the mechanism of silicon (Si) fertilizer in improving nitrogen (N) and phosphorus (P) nutrient availability in paddy soil, we designed a series of soil culture experiments by combining application of varying Si fertilizer concentrations with fixed N and P fertilizer concentrations. Following the recommendations of fertilizer manufacturers and local farmers, we applied Si in concentrations of 0, 5.2, 10.4, 15.6, and 20.8 μg/kg. At each concentration of added Si, the availability of soil N and P nutrients, soil microbial activity, numbers of ammonia-oxidizing bacteria and P-decomposing bacteria which means that the organic P is decomposed into inorganic nutrients which can be absorbed and utilized by plants, and urease and phosphatase activity first increased, and then decreased, as Si was added to the soil. These indicators reached their highest levels with a Si application rate of 15.6 μg/kg, showing values respectively 19.78%, 105.09%, 8.34%, 73.12%, 130.36%, 28.12%, and 20.15% higher than those of the controls. Appropriate Si application (10.4 to 15.6 µg/kg) could significantly increase the richness of the soil microbial community involved in cycling of N and P nutrients in the soil. When the Si application rate was 15.6 μg/kg, parameters for characterizing microbial abundance such as sequence numbers, operational taxonomic unit (OTU) number, and correlation indices of microbial community richness such as Chao1 index, the adaptive coherence estimator (ACE) index, Shannon index, and Simpson index all reached maximum values, with amounts increased by 14.46%, 10.01%, 23.80%, 30.54%, 0.18%, and 2.64%, respectively, compared with the control group. There is also a good correlation between N and P mineralization and addition of Si fertilizer. The correlation coefficients between the ratio of available P/total P (AP/TP) and the number of ammonia-oxidizing bacteria, AP/TP and acid phosphatase activity (AcPA), AP/TP and the Shannon index, the ratio of available N/total amount of N (AN/TN) and the number of ammoniated bacteria, and AN/TN and AcPA were 0.9290, 0.9508, 0.9202, 0.9140, and 0.9366, respectively. In summary, these results revealed that enhancement of soil microbial community structure diversity and soil microbial activity by appropriate application of Si is the key ecological mechanism by which application of Si fertilizer improves N and P nutrient availability.Keywords：Silicon;Paddy soil;Nitrogen and phosphorus nutrient availability;Microbial community structure nutrient- 63
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Published：2021-07-23 -
Screening beneficial bacteriostatic lactic acid bacteria in the intestine and studies of bacteriostatic substances
Abstract：Lactic acid bacteria (LAB) are a representative probiotic. As the dominant flora in the human intestinal tract, LAB can regulate the balance of human intestinal flora and improve host health. The purpose of this study was to isolate and screen LAB that are well suited to the intestinal characteristics of the Chinese population, with excellent probiotics and high antibacterial activity. After 16S ribosomal RNA (rRNA) homology and phylogenetic tree analysis, potential probiotics were tested for their antibacterial activity, resistance to artificial gastrointestinal fluid and drugs, surface hydrophobicity, and safety. Three strains of LAB with acid resistance, bile salt resistance, epithelial cell adhesion, and no multidrug resistance were selected: Lactobacillus salivarius, Leuconostoc lactis, and Lactobacillus paracasei. Analysis of the antibacterial active substances in the three strains and their fermentation broths revealed that the main antibacterial substances of L. lactis were organic acids, whereas those of L. salivarius and L. paracasei were organic acids and bacteriocins with broad-spectrum antibacterial activity. These three strains of probiotic LAB with high antibacterial activity were identified as bacterial resources that could potentially be used to develop probiotic preparations for the prevention and treatment of intestinal diseases caused by intestinal pathogens.Keywords：Intestinal lactic acid bacteria;Screening;Probiotic;Bacteriostatic substance- 117
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Published：2021-07-23 -
Potential effect of EGCG on the anti-tumor efficacy of metformin in melanoma cells
Abstract：Metformin, a first-line drug for type 2 diabetes mellitus, has been recognized as a potential anti-tumor agent in recent years. Epigallocatechin-3-gallate (EGCG), as the dominant catechin in green tea, is another promising adjuvant agent for tumor prevention. In the present work, the potential effect of EGCG on the anti-tumor efficacy of metformin in a mouse melanoma cell line (B16F10) was investigated. Results indicated that EGCG and metformin exhibited a synergistic effect on cell viability, migration, and proliferation, as well as signal transducer and activator of transcription 3/nuclear factor-κB (STAT3/NF-κB) pathway signaling and the production of inflammation cytokines. Meanwhile, the combination showed an antagonistic effect on cell apoptosis and oxidative stress levels. The combination of EGCG and metformin also differentially affected the nucleus (synergism) and cytoplasm (antagonism) of B16F10 cells. Our findings provide new insight into the potential effects of EGCG on the anti-tumor efficacy of metformin in melanoma cells.Keywords：Epigallocatechin-3-gallate (EGCG);Metformin;Melanoma;Anti-tumor efficacy- 23
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Published：2021-07-23 -
New insights on the utilization of ultrasonicated mustard seed cake: chemical composition and antagonistic potential for root-knot nematode,
Meloidogyne javanica Abstract：This study focused, for the first time, on the effect of ultrasonic features on the extraction efficiency of secondary metabolites in mustard seed cake (MSC). The nematostatic potential of sonicated seed cake was examined against the second-stage juveniles (J2s) of root-knot nematode, Meloidogyne javanica. The results show that a 35 ppm (parts per million) concentration of a sonicated extract (SE) sample of MSC caused 65% J2s mortality at 18 h exposure period in vitro. It also significantly suppressed the root-knot index (RKI=0.94) in tomato roots. The lethal concentration values for SE were 51.76, 29.79, and 13.34 ppm, respectively, at 6, 12, and 18 h of the exposure period, and the lethal concentration values for the non-sonicated extract (NSE) sample were 116.95, 76.38, and 55.59 ppm, respectively, at similar exposure time. Sinapine and gluconapin were identified as the major compounds in ultrasonic-assisted MSC. Because of the high extraction efficiency of metabolites in the SE, all treatments of SE were shown to be antagonistic to J2s. Thus, this study of ultrasonication activity-based profiling of MSC may help generate target-based compounds at a scale relevant to the control of disease caused by nematodes in economic crops.Keywords：Plant-parasitic nematode;Plant by-product;Sono-extraction;Liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS);Natural compound;Nematode management- 19
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Published：2021-07-23 -
Inhibitory mechanism of angiotensin-converting enzyme inhibitory peptides from black tea
Abstract：The aim of this work is to discover the inhibitory mechanism of tea peptides and to analyse the affinities between the peptides and the angiotensin-converting enzyme (ACE) as well as the stability of the complexes using in vitro and in silico methods. Four peptide sequences identified from tea, namely peptides I, II, III, and IV, were used to examine ACE inhibition and kinetics. The half maximal inhibitory concentration (IC50) values of the four peptides were (210.03±18.29), (178.91±5.18), (196.31±2.87), and (121.11±3.38) μmol/L, respectively. The results of Lineweaver-Burk plots showed that peptides I, II, and IV inhibited ACE activity in an uncompetitive manner, which requires the presence of substrate. Peptide III inhibited ACE in a non-competitive manner, for which the presence of substrate is not necessary. The docking simulations showed that the four peptides did not bind to the active sites of ACE, indicating that the four peptides are allosteric inhibitors. The binding free energies calculated from molecular dynamic (MD) simulation were -72.47, -42.20, -52.10, and -67.14 kcal/mol (1 kcal=4.186 kJ), respectively. The lower IC50 value of peptide IV may be attributed to its stability when docking with ACE and changes in the flexibility and unfolding of ACE. These four bioactive peptides with ACE inhibitory ability can be incorporated into novel functional ingredients of black tea.Keywords：Black tea;Angiotensin-1-converting enzyme (ACE) inhibitory peptide;Kinetic study;Molecular docking;Molecular dynamic (MD) simulation- 125
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Published：2021-07-23 -
Opposite effects of miR-155 in the initial and later stages of lipopolysaccharide (LPS)-induced inflammatory response
Abstract：Although microRNA-155 (miR-155) is considered a pro-inflammatory mediator, cumulative evidence indicates that it also has anti-inflammatory effects in macrophages and dendritic cells. In this study, we identified the dramatic expression changes of more than half of potential miR-155-targeted genes upon lipopolysaccharide (LPS) stimulation; 223 genes were down-regulated and 85 genes were up-regulated, including suppressor of cytokine signaling 1 (SOCS1) and transforming growth factor-β-activated kinase 1-binding protein 2 (TAB2), two well-known genes involved in miR-155-mediated regulation of the Toll-like receptor 4 (TLR4) signaling pathway. We also found that miR-155 acted as an anti-inflammatory mediator in the initial stage of LPS-induced inflammatory response mainly through repressing TAB2 protein translation, and as a pro-inflammatory mediator by down-regulating SOCS1 in the later stage. Meanwhile, overexpression of TAB2 3' untranslated region (UTR) in macrophages promoted the development of endotoxin tolerance by competing for binding with miR-155, which resulted in an elevated expression level of SOCS1 protein. These findings provide new insights for understanding the regulatory mechanisms in fine-tuning of LPS-induced innate immune response.Keywords：Toll-like receptor 4 (TLR4);Endotoxin tolerance;MicroRNA-155 (miR-155);Suppressor of cytokine signaling 1 (SOCS1);Transforming growth factor-β-activated kinase 1-binding protein 2 (TAB2)- 136
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Published：2021-07-23
Research Article
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Arthrospira maxima (Spirulina ) prevents endoplasmic reticulum stress in the kidney through its C-phycocyaninKeywords：C-藻蓝蛋白;极大节螺藻;螺旋藻;肾脏内质网胁迫;肾保护- 112
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Published：2021-07-23
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