摘要：
Five flavones possessing one to four phenolic groups were fully phosphorylated efficiently and the obtained compounds showed excellent pancreatic cholesterol esterase (CEase) inhibitory activities with IC(50) in the nanomolar range, which were much more potent than their parent compounds. The inhibition mechanism and kinetic characterization studies indicate that they are irreversible competitive inhibitors.
关键词：
Cucumber;Wild cucumber;Satellite repeats;Fluorescence in situ hybridization (FISH)
摘要：
Repetitive DNA sequences with variability in copy number or/and sequence polymorphism can be employed as useful molecular markers to study phylogenetics and identify species/chromosomes when combined with fluorescence in situ hybridization (FISH). Cucumis sativus has three variants, Cucumis sativus L. var. sativus, Cucumis sativus L. var. hardwickii and Cucumis sativus L. var. xishuangbannesis. The phylogenetics among these three variants has not been well explored using cytological landmarks. Here, we concentrate on the organization and distribution of highly repetitive DNA sequences in cucumbers, with emphasis on the differences between cultivar and wild cucumber. The diversity of chromosomal karyotypes in cucumber and its relatives was detected in our study. Thereby, sequential FISH with three sets of multi-probe cocktails (combined repetitive DNA with chromosome-specific fosmid clones as probes) were conducted on the same metaphase cell, which helped us to simultaneously identify each of the 7 metaphase chromosomes of wild cucumber C. sativus var. hardwickii. A- standardized karyotype of somatic metaphase chromosomes was constructed. Our data also indicated that the relationship between cultivar cucumber and C. s. var. xishuangbannesis was closer than that of C. s. var. xishuangbannesis and C. s. var. hardwickii
摘要：
Cold stress is one of the major abiotic stresses limiting the productivity and the geographical distribution of many important crops. To gain a better understanding of cold stress responses in tobacco ( Nicotiana tabacum ), we carried out a comparative proteomic analysis. Five-week-old tobacco seedlings were treated at 4°C for 4 h. Cold treatment resulted in stress phenotypes of smoothing and shallowing leaves and increased relative electrolyte leakage. The expression changes of total proteins in tobacco leaves were examined using two-dimensional electrophoresis. Quantitative image analysis revealed a total of 101 protein spots that changed their intensities significantly, 21 protein spots were down-regulated, eight were up-regulated after the cold treatment, 50 protein spots only expressed in the control sample, while 22 protein spots were only present in the cold treatment sample. Mass spectrometry analysis allowed the identification of 73 differentially expressed proteins, including well known and novel cold-responsive proteins. The identified proteins are involved in several processes such as photosynthesis, protein processing, redox homeostasis, ribonucleic acid (RNA) processing, signal transduction, translation, cell division/cycle, and metabolisms of carbon and energy. Several types of proteins showed enhanced degradation during chilling stress, especially the photosynthetic proteins. Gene expression analysis of 25 different proteins by reverse transcriptase- polymerase chain reaction (RT-PCR) showed that the messenger RNA (mRNA) levels of 18 genes correlated well with the protein levels. In conclusion, our study provides new insights into cold stress responses in tobacco and needs to be further studied in future. Key words : Proteomics, cold stress, tobacco (Nicotiana tabacum).
摘要：
The potential for photo-induced dissociation of ferri- and ferro-cyanide was investigated. The overall reactions followed first order kinetics, judged by the free cyanide analyzed in aqueous solution. The dissociation rates for ferri- and ferro-cyanide were mathematically described by the equations: C
(CN,t) = C
(CN,O)e1.3t
and C
(CN,t) = C
(CN,O)e0.39t
, respectively. In addition, photo-induced dissociation of both iron cyanides was enhanced under an alkaline environment than a neutral condition. Results from the temperature-dependent tests indicated that the dissociation rate of ferri- cyanide was significantly higher than that of ferro-cyanide at all treatment temperatures. The kinetic parameter, activation energy (E
a
) was also experimentally determined to be 12.02 and 12.32 kJ/mol for ferri- and ferro-cyanide, respectively. The results obtained suggest that both iron cyanides are susceptible to photo-dissociation and the rates are positively correlated to the change of temperatures. The information collectively also has important implications for waste management of iron cyanides as well as for risk assessment in a field trial.
摘要：
Forty-eight German Landrace weaned pigs were used in this study to investigate the effects of Lfcin B and Cec P1 on performance, faecal score and DM of weaned piglets orally challenged with enterotoxigenic Escherichia coli F4. The piglets were assigned randomly into four groups: Control, enterotoxigenic Escherichia coli F4ac (ETEC), enterotoxigenic Escherichia coli F4ac (ETEC)+lactoferricin B (Lfcin B) and enterotoxigenic Escherichia coli F4ac (ETEC) +Cecropin P1 (Cec P1) on the basis of weight and litter. All piglets in three experimental groups were orally challenged with 3x109 cfu E.coli K88 O149:K91:F4ac on d 29 and 30. Lfcin B and Cec P1 were administered orally as a single dose of 2 mg per piglet on d 29 after being challenged ETEC F4ac 3 hours later. From the age of 30 days, the piglets were offered feed and water ad libitum. The results showed that there were no significant differences on daily weight, ADG and ADFI (P>0.05) of piglets among the four groups during the experimental period. From d 28 to 35, the piglets in Cec P1 groups kept higher daily weight (p>0.05) than those in other three groups. There were no differences for faecal score and feces dry matter among the four groups. But there was a tendency piglet in Cec P1 group kept the balance of faecal score and feces dry matter. Though there are no obvious effects, Lfcin B and Cec P1 have potential use without toxicity in vivo as additive in the husbandry product.
摘要：
Double B-box 1a (DBB1a) belongs to the zinc-finger family proteins in Arabidopsis thaliana. Transcriptional analysis uncovered that the DBB1a gene expression was blue light-dependently regulated, and the transcript level of DBB1a in cry1cry2 was decreased but not in phyAphyB compared to wild type under blue light conditions. Transgenic plants containing pDBB1a:GUS (β-glucuronidase) displayed GUS activity in the vascular system of leaves and petioles. Green fluorescent protein (GFP)-fused DDB1a (DBB1a-GFP) protein was found in the nucleus in transient transformation assays with onion epidermal cells as well as in stable transgenic Arabidopsis plants. To investigate the function of DBB1a, we generated DBB1a over-expressing and under-expressing transgenic Arabidopsis plants. Analysis of hypocotyl growth of these lines indicated that DBB1a promoted hypocotyl elongation under blue light condition. The phenotype of transgenic plants with DBB1a over-expression could be impaired by a gibberellin (GA)-biosynthesis inhibitor. Moreover, the expression analysis of GA metabolic and catabolic genes in DBB1a transgenic lines indicated that the DBB1a suppressed GA2-oxidase1 (GA2ox1) and GA2-oxidase8 (GA2ox8) expression, but induced GA3β-hydroxygenase1 (GA3ox1) and GA20-oxidase1 (GA20ox1) expression under blue light. Taken together, we concluded that DBB1a promotes hypocotyl elongation under blue light condition through an increase in bioactive GA levels in Arabidopsis.
摘要：
The y + LAT1 gene is a member of solute carrier family that encodes a protein, which plays a significant function in transport of neutral and dibasic amino acids. The Tibetan pig is an excellent local variety in China, which is able to tolerate and survive under the adverse conditions. The study cloned the cDNA sequence of Tibetan pig y + LAT1 (GenBank accession #EU390782), and evaluated the tissue distribution and developmental expression of y + LAT1 mRNA and protein in different parts of intestine in Tibetan suckling piglets. The results show that the y + LAT1 cDNA encodes 511 deduced amino acid residues and 12 putative transmembrane domains, which can be widely detected in many organs in Tibetan piglets. Expression patterns were similar in jejunum and ileum, where the mRNA and protein level was decreased before the suckling period and increased until Day 35, duodenum changed reversely. The jejunum posterior is the predominant expressional tissue in all days. These results indicated that the ontogenesis expression of y + LAT1 was not only differentially regulated by early development age but also differentially with distributed tissues along the small intestine.
期刊：
JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS,2010年12(6):1289-1296 ISSN：1454-4164
通讯作者：
Liang, Y.
作者机构：
[Ouyang, Y.; Liang, Y.] Cent S Univ, Res Ctr Modernizat Chinese Med, Coll Chem & Chem Engn, Changsha 410083, Hunan, Peoples R China.;[Tang, Z.] Hunan Agr Univ, Coll Biosci & Biotechnol, Changsha 410128, Hunan, Peoples R China.
通讯机构：
[Liang, Y.] C;Cent S Univ, Res Ctr Modernizat Chinese Med, Coll Chem & Chem Engn, Changsha 410083, Hunan, Peoples R China.
关键词：
Potential high energy density materials (HEDMs);Polynitrotriprismanes (PNNPs);Heats of formation (HOFs);Strain energies (SE);Disproportionation energy (DE);Bond dissociation energy (BDE)
摘要：
To further test whether polynitriprismanes can be capable of being potential high energy density materials (HEDMs), extensive theoretical calculations have been carried out to investigate on a series of polynitrotriprismanes (PNNPs): C6H6-n, (NO2)(n)(n=1 similar to 6). Heats of formation (HOFs), strain energies (SE), and disproportionation energy (DE) are obtained using B3LYP/6-311+G (2df, 2p)//B3LYP /6-31G* method by designing different isodesmic reactions, respectively. Detonation properties of PNNPs are obtained by the well-known Kamlet-Jacobs equations, using the predicted densities (p) obtained by Monte Carlo method and HOFs. It is found that they increase as the number of nitro groups n varies from 1 to 6, and PNNPs with have excellent detonation properties. The relative stability and the pyrolysis mechanism of PNNPs are evaluated by calculated bond dissociation energy (BDE). The comparison of BDE suggests that rupturing the C-C bond is the trigger for thermolysis of PNNPs. The computed BDE for cleavage of C-C bond (21.08kcal.mol(-1)) further demonstrates that only the hexanitrotriprismane can be considered to be the target of HEDMs.
摘要：
In this study, we used native gradient-polyacrylamide gel electrophoresis and electroelution (NGGEE) to purify enzymatic proteins from Trichoderma koningii AS3.2774. With this method, we purified eight enzymatic proteins and classified them to the cellulase system by comparing secretions of T. koningii in inductive medium and in repressive medium. It resulted in 24-fold beta-glucosidase (BG) purification with a recovery rate of 5.5%, and a specific activity of 994.6 IU mg(-1) protein. The final yield of BG reached 8 mu g under purifying procedure of NGGEE We also identified BG using the enzyme assay with thin-layer chromatography and MALDI-TOFMS. This BG had one subunit with a molecular mass of 69.1 kDa as determined by sodium dodecylsulfate-polyacrylamide gel electrophoresis. The hydrolytic activity of the BG had an optimal pH of 5.0, an optimal temperature of 50 degrees C. an isoelectric point of 5.68 and a K-m for p-nitrophenyl-beta-D-glucopyranoside of 2.67 mM. Taken together, we show that NGGEE is a reliable method through which mu g grade of active proteins can be purified. (C) 2010 Elsevier B.V. All rights reserved.
摘要：
The present study describes a rapid and sensitive HPLC method for the quantification of huperzine A (HupA) in Huperzia crispata (Huperziaceae). The sample extraction and preparation involved a simple, time-saving, single-solvent extraction, with each sample being analyzed within 12 min. The mobile phase was ammonium acetate (0.1 M, pH 6.0)-methanol (64 + 36, v/v) at a flow rate of 1.0 mL/min. Detection was at 308 nm. The calibration curve was linear from 0.049 to 7.84 μg (R<sup>2</sup> = 0.9997), with intraday and interday precision RSD of less than 2%. The extraction recovery rate was over 98.49%. Quantification of HupA was performed using this modified method, and the content of HupA was 1.86 times higher in the whole plant of H. crispata (218.17 ±1.55 μg/g) than in that of H. serrata (117.03 ±2.97 μg/g). In the whole plant of H. crispata, HupA mainly accumulated in the actively growing shoot tips, the apical bud, and the 10 youngest leaves, reaching 455.23 ±2.97 μg/g. The content of HupA in the samples from sunshine-sheltered sites was 3.45 times higher than in that from sunshine-abundant sites. The satisfactory results indicate that this modified method can be applied in the quality control of large-scale Huperziaceae plant extracts and that changes should be made in the cultivation of H. crispata so as to maximize the production of HupA.
摘要：
We studied the allelopathic effects of Mikania micrantha on seed vigour, seed germination and seedling growth of three receptor species (Robinia pseudoacacia L., Lolium perenne L. and Lagerstroemia indica L) under different exposure times. The target species were selected from the Mikania-'mvaded ecosystem in South China. The inhibitory effects on seed vigour, seed germination and seedling growth of these test species increased with increasing exposure times and at higher extract concentrations. Seed vigour was more sensitive to extracts of Mikania than seed germination and seedling growth. Robinia pseudoacacia was more resistant to Mikania extract than Lolium perenne and Lagerstroemia indica. We found that even short exposure time (50-100 h) to Mikania extract had strong allelopathic effects on seed vigour, seed germination and seedling growth of test species.
摘要：
Expression profiles of 12 class A rice heat shock transcription factor genes (OsHsfAs) were analyzed by semi-quantitative reverse transcriptase polymerase chain reaction. The OsHsfA genes exhibited tissue-specific expressions under normal condition. OsHsfA1a, A2d, and A9 were predominantly expressed in young spike. Expression responses of the 12 OsHsfAs under abiotic stresses were analyzed in the shoots of rice seedling. Most OsHsfA genes responded quickly to heat stress except for OsHsfA1a, A3, and A9 which were almost unaffected. In particular, OsHsfA2a expression in response to heat stress was highest among the heat shock factors examined. However, the majority of the increased OsHsfAs expression responses to salt, polyethylene glycol (PEG), and cold treatments primarily occurred during the later stages (3 to 24 h) of stress exposure. Furthermore, most of OsHsfA gene expressions were little affected and only a few (OsHsfA3, A4d, A7, and A9) genes had slow responses to cold treatment. The results indicate that the transcript levels of OsHsfAs during heat stress exposure were distinct from those of plants subjected to salt, PEG, and cold stresses, suggesting that there might be different regulatory networks between heat and non-heat stress.
关键词：
Rare earth element (REE);REE tracer method (REETM);Research progress;Soil erosion
摘要：
Rare earth elements (REEs) have been proved ideal tracers for soil erosion and aggregation. REE tracer method (REETM) used to study soil erosion, as a new technique, has been developed in recent 20 yr. It is able to quantitatively monitor the temporal and spatial variation of erosion intensity, compared with traditional approaches. The applications of REETM in studying of sediment differentiation law, erosion process evolution, determination of sediment sources and sedimentation investigations, and determination of prediction parameters, were reviewed. Some application limitations were summarized.
