ABSTRACT
A reduction of chemical fertilizers and improving fertilizer utilization rate are important for ensuring a balance between plant growth and minimizing the degradation of the black soil. We conducted a 2-year pot experiment with four treatments during 2019 and 2020, including T0: no fertilizer, T1: conventional use of chemical fertilizer, T2: 15% reduction of the chemical fertilizer combined with 400 kg·hm-2 of humic acid bio-fertilizer (HABF), and T3: 30% reduction of the chemical fertilizer combined with 600 kg·hm-2 of HABF, to examine the effect of reduction rates of chemical fertilizers combined with the HABF on soil microbial abundance, enzyme activity and nutrient content in maize cultivation. The results showed that the application of HABF significantly increased the abundance of soil bacteria and fungi, with the number of microbial colonies being positively correlated with the amount of HABF. When measured at the tassel stage of maize growth, T2 and T3 treatments significantly increased the activities of urease, sucrase, and catalase in soil by 11.4%-21.6%, 34.9%-46.7%, and 6.5%-13.4%, respectively. The available nitrogen contents in T2 and T3 treatments were higher than that in the T1 treatment by 8.2%-18.1%, which ensured the sufficient nitrogen supply to maize after the tassel stage. Soil available phosphorus and available potassium contents increased by 17.1%-121.0% and 9.6%-57.3%, respectively, compared with T1 treatment. With the increases of the amount of HABF, the activation effects of soil phosphorus and potassium and dry matter mass per plant increased significantly in T2 and T3 treatments compared with T1 treatment. In conclusion, HABF promoted the proliferation of soil bacteria and fungi, improved activities of catalase, urease, and sucrase, soil nutrient contents, and dry matter mass per plant. The 15% reduction of chemical fertilizer combined with 400 kg·hm-2 of HABF is the most suitable nutrient management strategy for maize production in black soil.
Subject(s)
Fertilizers , Soil , Agriculture/methods , Bacteria , Catalase , Fertilizers/analysis , Humic Substances , Nitrogen/analysis , Phosphorus , Potassium , Soil/chemistry , Sucrase , Urease , Zea maysABSTRACT
Research on in vitro culture and gene editing of domestic spermatogonial stem cells (SSCs) is of considerable interest but remains a challenging issue in animal science. In recent years, some progress on the isolation, purification, and genetic manipulation of porcine SSCs has been reported. Here, we summarize the characteristics of porcine SSCs as well current advances in their in vitro culture, potential usage, and genetic manipulation. Furthermore, we discuss the current application of gene editing in pig cloning technology. Collectively, this commentary aims to summarize the progress made and obstacles encountered in porcine SSC research to better serve animal husbandry, improve livestock fecundity, and enhance potential clinical use.
Subject(s)
Adult Germline Stem Cells , Gene Editing , Spermatogonia , Swine/genetics , Animals , MaleABSTRACT
OBJECTIVE: To establish a method for the simultaneous determination of 5 water-soluble vitamins including VB1, VB6, Nicotinic acid, Nicotinamide and Folic acid by high performance liquid chromatography. METHODS: Methanol (200 microL) was added to 50 microL human blood sample to precipitate proteins. The sample was frozen (-18 degrees C) for 30 min, and then centrifuged at 8000 r/min for 8 min. The supernatant was subsequently applied to the solid-phase cartridge for further purification. The elute was collected and evaporated to 0.20 mL under nitrogen in a water bath at the temperature of 50 degrees C and finally 50 microL of the sample was injected onto HPLC column for analysis. The five water-soluble vitamins were determined under optimized condition of solid phase extraction and chromatograph. RESULTS: The optimized condition for solid phase extraction (SPE) was identified as: AGT cleanert ODS C18 column as SPE column and CH3OH (2.4 mL)-H2O (0.6 mL) mixed liquor as eluent, with a flow rate of elution of 0.5 mL/min. The optimized chromatographic condition was identified as, Phenomenex C18 Luna column (250 x 4.6 mm, 5 microm) as analytical column under a temperature of 20 degrees C and 0.05 mol/L potassium dehydrogenates phosphate buffer (pH 6.0) and methanol as gradient elution with mobile phase with a flow rate of 0.9 mL/min. The detection wavelength was 266 nm. The correlation coefficients for the standard curves were greater than 0.999 in the range from 0 to 100 ng (RSD < 5%). The detection limits (S/N 2) ranged from 0.076 to 0.170 microg/mL. The recovery rate ranged from 80.2% to 115.0%. Except for Nicotinamide, the other four vitamins were detected successfully in the blood sample. CONCLUSION: This quick and convenient method can be applied to the simultaneous determination of 4 water-soluble vitamins in human serum samples. But the sensitivity for detecting Nicotinamide needs to be improved.
