Synthesis and α-glucosidase inhibitory mechanisms of bis(2,3-dibromo-4,5-dihydroxybenzyl) ether, a potential marine bromophenol α-glucosidase inhibitor

Bis(2,3-dibromo-4,5-dihydroxybenzyl) ether (BDDE), derived from the marine algae, is a potential α-glucosidase inhibitor for type 2 diabetes treatment. In the present study, a synthetic route was established as a valid approach to obtain BDDE. Fluorescence spectra, circular dichroism spectra and molecular docking methods were employed to elucidate the inhibitory mechanisms of BDDE against α-glucosidase. The results showed that BDDE could be prepared effectively and efficiently with the established synthetic methods. Synthetic BDDE bound with α-glucosidase and induced minor conformational changes of the enzyme. The docking results indicated the interaction between BDDE and α-glucosidase was driven by both hydrophobic forces and hydrogen bonds. The docked BDDE molecule was completely buried in the α-glucosidase binding pocket with part of the molecule reaching the catalytic center and overlapping with the position of glucose, and the rest of the molecule extending towards protein surface. This study provides useful information for the understanding of the BDDE-α-glucosidase interaction and for the development of novel α-glucosidase inhibitors.     

Marine Bromophenol Bis (2,3-Dibromo-4,5-dihydroxy-phenyl)-methane Inhibits the Proliferation,Migration, and Invasion of Hepatocellular Carcinoma Cells via Modulating β1-Integrin/FAK Signaling

Bis (2,3-dibromo-4,5-dihydroxy-phenyl)-methane (BDDPM) is a natural bromophenol compound derived from marine algae. Previous reports have shown that BDDPM possesses antimicrobial activity. In the present study, we found that BDDPM has cytotoxic activity on a wide range of tumor cells, including BEL-7402 cells (IC₅₀ = 8.7 μg/mL). Further studies have shown that prior to the onset of apoptosis, the BDDPM induces BEL-7402 cell detachment by decreasing the adherence of cells to the extracellular matrix (ECM). Detachment experiments have shown that the treatment of BEL-7402 cells with low concentrations of BDDPM (5.0 μg/mL) significantly inhibits cell adhesion to fibronectin and collagen IV as well as cell migration and invasion. High doses of BDDPM (10.0 μg/mL) completely inhibit the migration of BEL-7402 cells, and the expression level of MMPs (MMP-2 and MMP-9) is significantly decreased. Moreover, the expression of β1-integrin and focal adhesion kinase (FAK) is found to be down-regulated by BDDPM. This study suggests that BDDPM has a potential to be developed as a novel anticancer therapeutic agent due to its anti-metastatic activity and also indicates that BDDPM, which has a unique chemical structure, could serve as a lead compound for rational drug design and for future development of anticancer agents.     

稻田中2,3—乙烷二醇气体产生菌的签别和分离

该文调查了稻田中专—产生2、3—乙烷二醇气体细菌的状况。其主要结果如下:(1)淹水稻田产生2、3—乙烷二醇气的菌群以时间递变而变化。在整个培养期间细菌总数的10—40％是2.3乙烷二醇产气菌。细菌经玻板计数并清除后,从葡萄糖上获得分离后2、3—乙烷二醇产生菌,并精确检测。(2)分离的细菌株数为377,其中90个菌株会从萄萄糖培养基上生产2、3—乙烷二醇气     

α and β-galactosidase activities and oligosaccharide content in peanuts

Thirty-three peanut cultivars were examined for their alpha-1,6 and beta-1,4 galactosidase activities and oligosaccharide contents along with proximate compositions. The average moisture, protein, fat, ash, and carbohydrate contents were: 4.9%, 26.6%, 43.1%, 2.3% and 23.1%, respectively. The corresponding coefficients of variation were: 5.2%, 10.1%, 7.2%, 7.8% and 15.7%, respectively. Raffinose and stachyose contents (%) ranged from 0.05 to 0.12 and 0.31 to 0.61, respectively. The specific activity (micromol product/min/mg protein) of crude preparation of alpha-galactosidase for the 33 cultivars ranged from 1.096 to 2.784 for the non-germinated seeds and from not being detected in some samples up to 2.432 for the germinated seeds; the mean values for non-germinated and germinated seeds were: 1.781 and 1.410, respectively. The specific activity of beta-galactosidase ranged from 0.101 to 1.727 in the non-germinated seeds and from not being detected in some samples up to 0.898 in the germinated seeds. Germination decreased the activity of both galactosidases significantly (p < or = 0.05).     

“Antioxidant activity and characterization of protein fractions and hydrolysates from normal and quality protein maize kernels”

Maize is the main crop cultivated worldwide with more than 1 billion metric tons produced annually and is one of the most relevant sources of protein for human consumption in developing countries. Proteins and peptides isolated from maize exert relevant antioxidant activity which is increased by enzymatic hydrolysis. However, there is limited information about the antioxidant potential of proteins isolated from Quality Protein Maize (QPM) varieties and their hydrolysates. The aim of this research was to determine the differences in protein profile and antioxidant activity of protein fractions and hydrolysates between a hybrid white maize (Asgrow 773) and a QPM variety (CML-502). The biophysical evaluation and the total protein quantification by Kjeldahl and fractions by ninhydrin were consistent with the changes due to the breeding process of the QPM material. The antioxidant potential of the hydrolysates obtained from albumins and globulins had a 3-fold increase in both maize varieties. The prolamins hydrolysates presented an increase of 7-fold for the normal variety and 2-fold for the QPM variety. The results of this research allow indicate that the QPM varieties are a source of antioxidant peptides and promising candidates in the search for proteins and peptides with other bioactivities.     

Correlations between ultrastructure and photosynthesis in leaves of rice and barnyard-grass

The ultrastructure of the leaves of rice(Oryza sativa)and barnyardgrass(Echinochloa crus-galli)in their milking stage were studied withelectron microscopy.The content of chloro-     

Awards and training course

Prof YUAN Longping, Director of Hunan Hybrid Rice Research Center (HHRRC). won the Alan Shawn Feinstein World Hunger Awards for his research and education in Brown University of America Apr 14, 1993.     

Rebaling of silage and haylage and its effects on forage microbial and chemical composition—A pilot study

Use of big bale silage and haylage can be difficult on farms where daily forage consumption is comparatively low as speed of deterioration of forage after bale opening may be faster than feed-out rate. Production of smaller bales at harvest is possible, but expensive and work-intensive. Therefore, a pilot study of rebaling forage stored in big bales to smaller bales was conducted. Three separate experiments were included, where microbial and chemical composition of silage and haylage was studied before and after rebaling. In Experiment III, residual big bale forage stored and opened together with rebaled forage was included. Results showed that rebaled haylage and silage had higher yeast counts compared to initial forage; however, residual bales in Experiment III had yeast counts similar to rebaled forage, indicating an effect of storage time rather than of rebaling. In Experiment II, mould counts were higher in rebaled compared to initial silage, but not in haylage. Chemical composition was similar in initial and rebaled forage except for ammonia-N. In Experiment III, ammonia-N was higher in rebaled compared to initial and residual forage and was the only chemical variable affected by rebaling. Bale temperature during aerobic storage followed ambient temperature until day 6–8 in Experiment I and until day 14 in Experiment III where ambient temperature was lower. In conclusion, rebaling can be done without large changes in chemical composition of the forage, but yeast and mould counts may be higher in rebaled forage, and this risk should be considered when using this procedure.     

Synergistic and antagonistic interactions between potassium and magnesium in higher plants

Magnesium(Mg)affects various critical physiological and biochemical processes in higher plants,and its deficiency impedes plant growth and development.Although potassium(K)-induced Mg deficiency in agricultural production is widespread,the specific relationship of K with Mg and especially its competitive nature is poorly understood.This review summarizes current knowledge on the interactions between K and Mg with respect to their root uptake,root-to-shoot translocation and distribution in plants.Their synergistic effects on certain physiological functions are also described.The antagonistic effect of K on Mg is stronger than that of Mg on K in root absorption and transport within plants,indicating that the balanced use of K and Mg fertilizers is necessary for sustaining high plant-available Mg and alleviating K-induced Mg deficiency,especially in plant species with high K demand or in highavailable-K soil.The relationship between Mg and K in plant tissues may be antagonistic or synergistic depending on plant species,cell type,leaf age,source-and sink organs.There are synergistic effects of K and Mg on photosynthesis,carbohydrate transport and allocation,nitrogen metabolism,and turgor regulation.Definition of optimal K/Mg ratios for soils and plant tissues is desirable for maintaining proper nutritional status in plants,leading to a physiological state supporting crop production.Future research should concentrate on identifying the physiological and molecular mechanisms underlying the interactions between K and Mg in a given physiological function.     

Fertilizer rate and β-galactosidase and peroxidase activity in pepper fruit at different stages and years of harvest

Beta-galactosidase and peroxidase are enzymes reported to have roles in pepper maturation. Fertilizer rate may affect activity of these enzymes in fruit maturing on the plant. Nine pepper cultivars, five non-pungent and four pungent, were fertilized at two rates in field plots in 1997 and 1998 at Lane, OK, USA. Fruit were harvested at mature green, turning, and red color developmental stages, and assayed for beta-galactosidase and peroxidase activity. Overall fruit beta-galactosidase activity increased as fertilizer rate increased, and was highest in red fruit. Fertilizer rate and fruit developmental stage did not affect peroxidase activity in 1997, but peroxidase activity was highest in red fruit in 1998. Enzyme activity appeared to be cultivar dependent, and patterns differed in both years. Activities of both enzymes were higher at the red stage in many of the non-pungent peppers than in pungent peppers. These data suggest that increased fertilizer affects the activity of at least one enzyme in fruit maturing on the plant. Cultural practices affecting enzyme activity may be used to modify concentrations of components in plants that are important for human consumption.     

cDNA Cloning and Sequence Analysis of Rice Sbel and Sbe3 Genes

Two starch-branching enzyme (SBE) in rice, is known to be a key enzyme in amylopectin biosynthesis. The cDNA of two SBE(starch-branching enzyme) genes SheI and Shed encoding SBE Ⅰ and SBE Ⅲ (two major isoforms in rice) were cloned by an improved RT-PCR technique, from a template cDNA libray, derived from the total mRNAs extracted from the immature seeds of a japonica rice Wuyunjing 7. DNA sequence analysis showed that the size of the cloned SheI and Shed cDNAs were 2490 and 2481 bp long, respectively, including their entire coding sequences. Comparison analysis indicated that the nucleotide sequence of She3 was the same as that of shed (Genbank Accession No. D16201) as reported previously. There were only four base-pairs difference,which resulted in changes of two deduced amino acids between the cloned She1 cDNA and the reported she1 (Genbank Accession No. D11082). The cloned SheI and Shed cDNAs make it possible to improve rice starch quality through genetic engineering.     

Relationships between zeatin and zeatin riboside contents and grain filling of rice

Zeatin(Z)and zeatin riboside(ZR)are natu-rally-occurring and predominant transportablecytokinins in some higher plants.In thisstudy,the total contents of Z and ZR weremeasured in grains and roots,respectively,and their relationship with grain filling wereanalyzed.The grain filling percentage(GFP)and fertilized-grain filling percentage(FGFP)of rice cultivars IR72,IR 65600-42-5-2,IR65600-127-2-3,and IR 65598-112-2 grown infield and cultivars IR72,IR57298-174-1-1R,     

Combined pollution of Cd and Zn in soil-rice systems and its indexes

Due to the mining, smelting, sewage irrigation, agricultural runoff, and development of rural enterprises, combined pollution of Cd and Zn in soil-rice systems has frequently oceurred. This problem was studied by using the pot-culture imitative method combined with heroical analysis and mathematical models. Tested soil was brunisolic paddy soil and the tested concentrations of Cd and Zn were selected as follows: Cd (mg/kg) 0.0 0.5 1.0 1.5 2.0 3.0 Zn (mg/kg) 0.0 100 200 400 The results showed that the Cd-Zn combined pollution was more complicated than the single-factor pollution of Cd or Zn in soil-rice system: Influences of the Cd-Zn combined pollution on biological yield of rice, accumulation and distribution on Cd and Zn in tissues of rice were not only dependent on the concentration of Cd and Zn added into the tested paddy soil, but also related to their ratio. Under the condition of the Cd-Zn combined pollution, interrelationship between biological yield (Y) of rice and exponential logarithmic value     

Differences of photoinhibition and photooxidation between indica and japonica rice under varied conditions

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Productivity and management of rice–wheat cropping systems: issues and challenges

Rice (Oryza sativa L.) and wheat (Triticum aestivum L.) are now grown in sequence on the same land in the same year over 26 Mha of South and East Asia to meet the food demand of a rapidly expanding human population. This rice–wheat (R–W) system brings together conflicting and complementary practices. Much of the system operates at low yield because of inadequate nutrients and inappropriate water management. The challenge to research is to understand crop responses to the required combination of practices so that management systems can be devised for high and sustainable combined yield. The repeated transitions from anaerobic to aerobic to anaerobic growing conditions affect soil structure, nutrient relations, the growth of the component crops, and their associated pests and diseases. This review establishes realistic yield targets and discusses strategies and tactics to improve complementarity of the two crops by choice of cultivar, sowing time, mechanization, soil and water management, choice and combination of organic and inorganic fertilizers, management of weeds, pests and diseases, and the inclusion of other crops into the system, especially legumes. While research must attend to existing problems and improve resource-use efficiency of existing practices, the review suggests the need to look for new production strategies that might avoid existing constraints in some areas of the R–W region. In particular, soil, water and nutrient management strategies, such as reduced tillage and use of raised beds, that avoid the deleterious effects of puddling on soil structure and fertility, improve water- and nutrient-use efficiencies, and increase crop productivity, may be appropriate.     

Single and Competitive Adsorption of 17α-Ethinylestradiol and Bisphenol A with Estrone, β-Estradiol,and Estriol onto Sediment

The competitive adsorption of bisphenol A (BPA) and17α-ethinylestradiol (EE2) with different endocrine disrupting compounds (EDCs), such as estrone (E1), β-estradiol (E2), and estriol (E3) was investigated in the water-sediment system. The primary and interaction effects of coexisted EDCs on the adsorption of BPA and EE2 were studied in binary and multiple systems. The adsorption selectivity of sediment at different initial concentrations of EDCs was also considered, based on the distribution coefficient (β). In binary systems, coexisted EDCs exhibited a positive effect on the adsorption of BPA, while E3 showed a negative effect on the adsorption of EE2. In ternary systems, the interaction of E1*E3 and E2*BPA showed a synergistic effect on the sorption of BPA and EE2, respectively. In quaternary systems, the interaction of E1*E2*E3 showed a synergistic effect on the adsorption of both BPA and EE2. In the quinary system, coexisted EDCs all showed an antagonistic effect on the adsorption of BPA and EE2, which indicated that the coexisted EDCs competed for adsorption with BPA and EE2. EDCs in the E2-EE2-BPA system presented a superior selectivity of sediment with β values of 43.48–87.86. The order of sediment selectivity (E1 > EE2 > E2 > E3 > BPA) in binary systems was in agreement with EDCs’ adsorption capacity, which suggested that the adsorption was dominated by partition adsorption.     

Index Calculation and Analysis of China's Pesticide Import and Export During 2011–2020

正Using the trade data from the General Administration of Customs of China between January 2011 and December 2020, we estimated the index for China’s pesticide import and export, including annual import and export pesticide price index, quantity index and value index. We also calculated the terms of trade (TOT) of pesticide in total and by trade regions.