Effects of Mechanized,Deep Application of Slow-Release Fertilizer on Yield and Nitrogen,Phosphorus, and Potassium Utilization of Direct-Seeded Rice

Compared with the standard method of manual fertilizer broadcasting (MFB), mechanized hill-drilling direct-seeding with deep application of slow-release nitrogen fertilizer (MHDDF) is an efficient method to integrate both fertilization and seeding. However, there are few studies that combine the use of slow-release fertilizer with MHDDF. We sought to explore the combined effect of MHDDF with slow-release fertilizer on rice yield and nitrogen, phosphorus, and potassium utilization, compared to MFB. We compared three different MHDDF methods (D30: 450 kg ha^?1, D40: 600 kg ha^?1, D50: 750 kg ha^?1), with one MFB method (B50: 750 kg ha^?1), and one control (CK: 0 kg ha^?1). We found that the yield of all MHDDF method was higher than that of both the MFB method. Yield was the highest in the D50 treatment and was 14.14–46.03% higher than that in B50 treatment. Biomass accumulation, nutrient accumulation, and nutrient use efficiency were similarly higher in MHDDF method than both MFB and CK. Compared to B50, the D50 treatment increased nitrogen recovery efficiency by 170.53–231.50%, phosphorus recovery efficiency by 480.00–724.25%, and potassium recovery efficiency by 201.55–169.59%. Overall, we found that combining MHDDF with slow-release fertilizer was an effective method to increase rice yield and nutrient use efficiency compared with MFB.

     

冻干青春型双歧杆菌DM8504存活期的加速预测

本文介绍了加速贮存实验预测冻干活菌制品存活期的方法,并用此法对冻干青春型双歧杆菌ＤＭ８５０４的存活期进行了预测。结果表明,预测结果与实验测试结果非常接近,两者没有显著性统计学差异,笔者认为加速贮存实验法是预测冻干活菌稳定性的一种快速而可行的方法。     

Molecular diversity and phylogeny of rhizobia associated with wild legumes native to Xinjiang, China

A total of 111 rhizobial strains were isolated from wild legumes in Xinjiang, an isolated region of northwest China. Nine genomic species belonging to four genera of Rhizobium, Mesorhizobium, Ensifer, and Bradyrhizobium were defined among these strains based on the characterization of amplified 16S ribosomal DNA restriction analysis (ARDRA), restriction fragment length polymorphism (RFLP) analysis of 16S-23S rDNA intergenic spacers (IGS), 16S rRNA gene sequencing and multilocus sequence analysis (MLSA). Twenty-five nodC types corresponding to eight phylogenetic clades were divided by RFLP and sequence analysis of the PCR-amplified nodC gene. The acid-producing Rhizobium and Mesorhizobium species were predominant, which may be related to both the local environments and the hosts sampled. The present study also showed the limitation of using nod genes to estimate the host specificity of rhizobia.     

放牧对黄土高原退耕草地土壤有机碳储量的影响

放牧是影响草地土壤碳固存的重要因素。本研究选取黄土高原水蚀风蚀交错区西部、中部、东部地区及水蚀区,以各区20年以上退耕封禁地为对照,分析3个放牧强度下(羊粪球密度分别为0～10、10～20、>20 ind·m^-2)退耕草地0～20 cm土层土壤有机碳储量的分布特征,研究放牧及其强度对退耕草地土壤固碳效应的影响。结果表明: 放牧对交错区西部0～20 cm、东部0～10 cm,水蚀区0～5 cm土层土壤有机碳储量有显著影响,对交错区中部各土层均无显著影响;羊粪球密度0～10、＞20 ind·m^-2强度的放牧使交错区西部0～20 cm土层土壤有机碳储量显著降低了34.8%～50.9%,而在其他3个区域,放牧对有机碳储量的影响较退耕封禁地差异不显著。在交错区东部,放牧强度是影响退耕草地土壤有机碳储量的主要因素,而其他3个区域有机碳储量主要受土壤理化性质和(或)枯落物生物量的影响。羊粪球密度10～20 ind·m^-2强度的放牧对各区域退耕草地0～20 cm土层土壤有机碳储量无显著影响。     

Cholesterol Sulfate and Cholesterol Sulfotransferase Inhibit Gluconeogenesis by Targeting Hepatocyte Nuclear Factor 4α

Sulfotransferase (SULT)-mediated sulfation represents a critical mechanism in regulating the chemical and functional homeostasis of endogenous and exogenous molecules. The cholesterol sulfotransferase SULT2B1b catalyzes the sulfoconjugation of cholesterol to synthesize cholesterol sulfate (CS). In this study, we showed that the expression of SULT2B1b in the liver was induced in obese mice and during the transition from the fasted to the fed state, suggesting that the regulation of SULT2B1b is physiologically relevant. CS and SULT2B1b inhibited gluconeogenesis by targeting the gluconeogenic factor hepatocyte nuclear factor 4α (HNF4α) in both cell cultures and transgenic mice. Treatment of mice with CS or transgenic overexpression of the CS-generating enzyme SULT2B1b in the liver inhibited hepatic gluconeogenesis and alleviated metabolic abnormalities both in mice with diet-induced obesity (DIO) and in leptin-deficient (ob/ob) mice. Mechanistically, CS and SULT2B1b inhibited gluconeogenesis by suppressing the expression of acetyl coenzyme A (acetyl-CoA) synthetase (Acss), leading to decreased acetylation and nuclear exclusion of HNF4α. Our results also suggested that leptin is a potential effector of SULT2B1b in improving metabolic function. We conclude that SULT2B1b and its enzymatic by-product CS are important metabolic regulators that control glucose metabolism, suggesting CS as a potential therapeutic agent and SULT2B1b as a potential therapeutic target for metabolic disorders.     

Characterization of a metal-chelating substance in coffee

A metal-chelating substance in brewed coffee was separated and characterized by its chemical structure. This substance was a brown polymer. The contents of sugars, amino acids and phenolics in the substance were evaluated. This polymer contained small amounts of sugars and amino acids in its partial structure. After being decomposed by alkaline fusion, the decomposition products were identified by HPLC and GC-MS. Several phenolics were detected in the decomposed products. To characterize this substance, various types of model compounds were prepared by roasting chlorogenic acid, sucrose, and (or) protein with cellulose powder. Among these model compounds, the polymer-forming ability was highest in the model prepared from all four of materials, but the metal-chelating ability was the highest in the model prepared from chlorogenic acid and cellulose. These results suggest that this metal-chelating substance was a melanoidin-like polymer formed by the decomposition and polymerization of sugars, amino acids and phenolics.     

儿童最大有氧活动能力的发展特征

本文报告了我国４６３名１０－１９岁儿童青少年的最大有氧活动能力的发展特征。在青春早期,男女童的最大吸氧量绝对值均随年龄增长而增加,男童由１．７５升／分增至３．１０升／分,女童由１．４４升／分增至２．０７升／分,女童增长较少;以后女童即稳定于这一水平,男童仍略有增长。按身高及按最大心率计标的相对值与其有相似的特征。按体重和瘦体重计算的相对值,在男女童都未见随年龄增长的规律。男童ＶＯ２ｍａｘ绝对值及各     

Comparison of global DNA methylation profiles in replicative versus premature senescence

DNA methylation is considered to play an essential role in cellular senescence. To uncover the mechanism underlying cellular senescence, we established the model of premature senescence induced by hydrogen peroxide (H(2)O(2)) in human embryonic lung fibroblasts and investigated the changes of genome methylation, DNA methyltransferases (DNMTs) and DNA-binding domain proteins (MBDs) in comparison with those observed during normal replicative senescence. We found that premature senescence triggered by H(2)O(2) exhibited distinct morphological characteristics and proliferative capacity which were similar to those of replicative senescence. The genome methylation level decreased gradually during the premature as well as replicative senescence, which was associated with the reduction in the expression of DNMT1, reflecting global hypomethylation as a distinct feature of senescent cells. The levels of DNMT3b and methyl-CpG binding protein 2 (MeCP2) increased in both mid-aged and replicative senescent cells, while DNMT3a and MBD2 were upregulated in the mid-aged cells. Only DNMT3b was elevated in the cells in the premature senescence persistence status. Additionally, the expression for DNMTs, MBD2 and MeCP2 was increased rapidly upon H(2)O(2) treatment. These results indicate that H(2)O(2)-induced premature senescence share some features of replicative senescence, such as basic biological characteristics and global hypomethylation while there are slight differences in the profile of methylation-associated enzyme expression. Oxidative damage may hence be a causative factor in epigenetic alteration partly responsible for cellular senescence.