Evaluation and characterization of an endosperm-specific sbeⅡa promoter in wheat

Starch,the main component of the wheat grain,is the product of a complex biochemical pathway. The sbeⅡα gene plays a key role in controlling the synthesis of starch, in particular, the biosynthesis of amylopectin,in maturing wheat grain.To investigate its regulatory mechanisms and endosperm-specific expression pattern, the sbeⅡα promoter (3094 bp in length) was cloned using APCR and sequenced.The effect of a series of deletions was studied using a GUS transient assay system. Results showed that the 3094 bp sequence (sbe.g construct) exhibited full stable promoting activity and that the activities of 5′ or 3′ deletions reduced levels of GUS expression. Some constructs with internal deletions showed only weak activity, however,sbe.e, with a deletion from -1579—--1210 bp resulted in higher levels of expression than the full-length promoter sequence, sbe.g. This indicates that motifs such as the -300 bp element, G-box and/or P-box act as positive elements and are necessary in determining the promoter‘s endosperm-specific pattern and that negative repressor elements or motifs may also be present within the -1579—-1210 bp sequence. The age of wheate ndosperm tissue used in the GUS-transient assay system is shown to be of significant importance.     

Synthesis and characterization of a three-ring bent-core compound

To investigate the vacuum-deposited films of the banana-shaped mesogens, we prepared a three-ring bent-core （that is, banana-shaped） compound m-bis（4-p-octoxysryrenyl）benzene （m-OSB） and used it as a prototype for studying the related film physics. Herein the synthesis and the structural characterization of m-OSB are reported.^13C and ^1H NMR spectra and ^1R spectrum confirm that m-OSB has a symmetric and all-trans conformation. The results of differential scanning calorimetry, polarizing optical microscopy and X-ray diffractometry indicate that no liquid crystalline phase but two crystalline phases are present in this material： phase Ⅰ （T〈66℃） and phase Ⅱ （66~C〈T〈157℃）; an isotropic state is observed at above 157℃. Combining the X-ray diffraction and the electronic diffraction, we assign the room-temperature crystalline phase I to orthorhombie system and P212121 space group with cell parameters of a = 7.43A°. b=6.34A°, c=72.07A°, and α=β=γ=90°. Molecular modeling reveals that the molecules in the unit cell adopt a layered structure with an antiferro-eleetrie alignment. The structure of phase Ⅱ is very similar to that of phase Ⅰ. Nonlinear optical measurement shows that m-OSB is active for the second harmonic generation （SHG）. Such characterization of the bulk material is necessary for the understanding of the growth and microstructures in the films.     

Quantitative Analysis and Evaluation of Block Strategies in Volleyball

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Experimental Evaluation of TCP and ICMP in Network Measurement

Network measurement is an important approach to understand network behaviors, which has been widely studied. Both Transfer Control Protocol （TCP） and Interact Control Messages Protocol （ICMP） are applied in network measurement, while investigating the differences between the measured results of these two protocols is an important topic that has been less investigated. In this paper, to compare the differences between TCP and ICMP when they are used in measuring host connectivity, RTT, and packet loss rate, two groups of comparison programs have been designed, and after careful evaluation of the program parameters, a lot of comparison experiments are executed on the Internet. The experimental results show that, there are significant differences between the host connectivity measured using TCP or ICMP; in general, the accuracy of connectivity measured using TCP is 20%- 30% higher than that measured using ICMP. The case of RTT and packet loss rate is complicated, which are related to path loads and destination host loads. While commonly, the RTF and packet loss rate＂ measured using TCP or ICMP are very close. According to the experimental results, some advices are also given on protocol selection for conducting accurate connectivity, RTF and packet loss rate measurements.     

Cloning of the full-length gene of activin receptor-interacting protein2a and characterization of its interaction with ActR Ⅱ A

To investigate the mechanism of intracellular signal transduction mediated by activin receptors, the full-length gene encoding a novel activin receptor-interacting protein2a (ARIP2a) was identified from a mouse brain cDNA library. The sequences of ARIP2a and ARIP2, distribution of ARIP2a and ARIP2 mRNA in mouse tissues, and expression of ARIP2a and ARIP2 in activin-induced RAW264.7 cell were compared, and the interaction between ARIP2a and ActRIIA was confirmed. The sequence analysis revealed that the full-length gene of ARIP2a, which composed of 1008 bp and encoded 153 amino acid residues, shared high sequence identity with ARIP2 except the position of the 99th amino acid. RT-PCR assay showed that ARIP2a mRNA was highly expressed in brain, pituitary and testis, and moderately in pancreas and ovary, but undetectable in other tissues. Whereas, ARIP2 mRNA was widely distributed in all mouse tissues that we tested. Moreover, expression of ARIP2a mRNA was significantly decreased in activin-stimulated RAW264. 7 cells; however, the expression of ARIP2 mRNA was increased. Additionally, the interaction between ARIP2a and activin type IIA receptor (ActRIIA) was further demonstrated by mammalian two-hybrid assays and pull-down assays. Taken together, those results indicate that although ARIP2a is homologous to ARIP2, they are different in tissue distribution and responses to activin. ARIP2a could also interact with activin type II receptor as a novel member of ARIP family.     

Cloning of the full-length gene of activin receptor-interacting protein2a and characterization of its interaction with ActRⅡA

To investigate the mechanism of intracellular signal transduction mediated by activin receptors, the full-length gene encoding a novel activin receptor-interacting protein2a (ARIP2a) was identified from a mouse brain cDNA library. The sequences of ARIP2a and ARIP2, distribution of ARIP2a and ARIP2 mRNA in mouse tissues, and expression of ARIP2a and ARIP2 in activin-induced RAW264.7 cell were compared, and the interaction between ARIP2a and ActRIIA was confirmed. The sequence analysis revealed that the full-length gene of ARIP2a, which composed of 1008 bp and encoded 153 amino acid residues, shared high sequence identity with ARIP2 except the position of the 99th amino acid. RT-PCR assay showed that ARIP2a mRNA was highly expressed in brain, pituitary and testis, and moderately in pancreas and ovary, but undetectable in other tissues. Whereas, ARIP2 mRNA was widely distributed in all mouse tissues that we tested. Moreover, expression of ARIP2a mRNA was significantly decreased in activin-stimulated RAW264.7 cells; however, the expression of ARIP2 mRNA was increased. Additionally, the interaction between ARIP2a and activin type IIA receptor (ActRIIA) was further demonstrated by mammalian two-hybrid assays and pull-down assays. Taken together, those results indicate that although ARIP2a is homologous to ARIP2, they are different in tissue distribution and responses to activin. ARIP2a could also interact with activin type II receptor as a novel member of ARIP family.     

Observation and Evaluation of Bridge Settlement in Beijing-Tianjin Intercity Railway

Specific requirements and methods of settlement monitoring which were used in bridge of unballasted track passenger dedicated line or high-speed railway are introduced systematically,and mathematical model and determinant conditions of settlement were proposed simultaneously,taking Beijing—Tianjin intercity railway as an example.     

Evaluation System and Actualization of Selection Supplier in ERP Enterprise

Suppliers become an essential factor of enterprise competitiveness. The analytic hierarchy process is a kind of Decision-making method with the combination of quantity and quality. This paper presents the evaluation system of supplier selection, using Analytic Hierarchy Process （AHP） method to select the optimum supplier in Enterprise Resource Planning （ERP） enterprise. In order to reduce factor of manmade and increase exactitude, this paper innovates to use a real database in ERP system for evaluation. It also gives an example that one enterprise selects supplier.     

Development, chromosome location and genetic mapping of EST-SSR markers in wheat

A number of 151695 wheat expression sequence tags （ESTs） that originated from GenBank/dbEST from July 14, 2003 to August 24, 2004 were used to search for simple sequence repeats （SSRs） with motif 2-5 bp, and 2038 simple sequence repeats （EST-SSRs）, which accounted for 1.34% of EST database, were identified. Based on these SSR sequences, 249 EST-SSR primer pairs and 166 amplified clear bands in various wheat cultivars were designed. These EST-SSR markers can be used as new molecular markers in wheat and related species. Using Chinese Spring nulli-tetrasomic lines, 93 EST-SSR primer pairs and 193 EST-SSR loci were located on 19 wheat chromosomes except for 4A and 4B. Forty-three loci were mapped on 11 chromosomes of the genetic framework map previously constructed using recombinant inbred lines.     

Combinational biosynthesis and characterization of a fluorescent 82β-phycocyanin of Spirulina platensis

To biosynthesize fluorescent Spirulina platensis (Sp)β -phycocyanin (PC) in Escherichia coli, a BLASTP search for homologs of the cpeS gene, a chromophore lyase, was performed against the Synechocystis sp. PCC 6803 (S6) proteome. A highly homologous gene, slr2049, was obtained from the S6 genome. Sites 82 and 153 in -phycocyanin of Sp were modified by site-directed muta- genesis. Two recombinant expression vectors were constructed and transformed into E. coli BL21: (i) pCDF-cpcB (C153A)- slr2049-sll0583-ho1-pcyA; and (ii) pCDF-cpcB (C82I)-slr2049-sll0583-ho1-pcyA. Lyases encoded by the genes slr2049 and sll0583 catalyzed the linking of Sp 82β -PC to phycocyanobilin (PCB), and fluorescent CpcB (C153A)-PCB was generated. We present a strategy for the co-expression of multiple genes in a single expression vector to identify the function of an unknown gene. Recombinant phycobiliproteins produced on a large scale are promising fluorescent tags for diagnostics and pharmacology.     

Cloning of a down-regulated gene encoding small GTP binding protein in hybrid wheat

Previous studies showed that differential gene expression between wheathybrids and their parents was responsible for the heterosis. To provide an insight into the molecular basis of wheat heterosis, one cDNA, designated TaRab, was identified from the cDNA library of wheat seedling leaves. The sequence comparison in GenBank revealed that TaRab is homologous to a group of genes encoding Rab-GTP binding protein. Semi-quantitative RT-PCR analysis indicated that TaRab was expressed in all plant tissues examined, but at slightly higher level in leaves. Further analysis exhibited that TaRab displayed lower expression in hybrid than in its patents in both roots and leaves, which was in agreement with the original results of suppression subtractive hybridization. TaRab was located on chromosome 7B and C-7DS5-0.36 by in silico mapping. The relationship between differential expression of TaRab and the molecular basis of wheat heterosis was also discussed.     

Identification of seed-specific promoter nap300 and its comparison with 7S promoter

By fusing seed-specific promoter nap300 with β-glucuronidase gene, it was found that this about 300bp DNA fragment was sufficient to direct seed-specific gene expression. The substitution mutation in both distB and proxB elements had a little effect on the expression efficiency and almost no effect on the organ-specific expression pattern. In the experiment designed to compare nap300 with 7S promoter, the result showed that tissue specificity for nap300 was higher than that for 7S, and its expression level was lower than 7S's. There was no big difference in their expression pattern, and the maximal activity stage for the two promoters was identical, which indicated they could be used simultaneously for expressing different foreign genes in seeds.     

Effects of stem structure and cell wall components on bending strength in wheat

Stem is an important organ consisting of storage, transportation and mechanical tissues and is closely related to yield. There is an irregular cavity in the ce- real crop stems and the lower the location, the shorter and thicker the walls of the internode…     

Synthesis and characterization of Au@Pt nanoparticles

Aucore-Ptshell （Au@Pt） nanoparticles were synthesized at room temperature by reducing K2PtCl6 with hydrogen in the solution containing Au colloids and polyvinylpyrrolidone （PVP）. The particles obtained were characterized with UV-Vis, TEM and XPS techniques. UV-Vis spectra show that the surface plasmon absorption feature of Au colloids is significantly reduced with increasing the amount of reduced Pt. TEM images that the metals are found always appear as spherical nanoparticles and their sizes grow apparently due to the reduction of PtCl6^2- ions, indicating that Pt is deposited from solution onto Au particle surface and forms a Pt-layer with uniform thickness. In the XPS spectra, the signals of Au metal decrease due to the reductive deposition of Pt on the surface of the Au colloids. UV-Vis and XPS data are consistent in showing that when the amount of Pt in the AuPt colloids is increased to reach an overall atomic ratio of Pt/Au=2, the Pt deposits form a shell covering completely the surface of Au particles, demonstrating the core-shell structure of the synthesized AuPt particles.     

Identification and characterization of a salt tolerance-responsive gene( AtGRP9) of Arabidopsis

Soil salinity is one of the important limiting factors for plant growth and development. A cDNA clone encoding a glycine-rich protein (designated AtGRP9) was identified from Arabidopsis by functional expression of the plant cDNA library in the fission yeast S. pombe. Yeast cells overexpressing AtGRP9 displayed significantly enhanced salt tolerance. Northern analysis showed that expression of AtGRP9 in Arabidopsis was induced by NaCl and plant hormone abscisic acid (ABA). These results suggest that AtGRP9 may be involved in the salt stress response in Arabidopsis.     

Isolation and characterization of rl（t）, a gene that controls leaf rolling in rice

Moderate leaf rolling is one of the most important morphological traits in rice breeding for plant ideotype. Previous studies have shown that the rl（t） gene has a high breeding potential for developing hybrid-rice varieties with an ideal ideotype, because it leads to an appropriate leaf rolling index （LRI） of about 30 % in the heterozygous state, and had a positive effect on grain yield. In this study, we isolated rl（t） and performed a preliminary investigation of its function in regulating leaf rolling in rice. DNA sequencing identified a single base change （G to T） in the finely mapped region （11 kb） containing rl（t）, and this is located in 3′-untranslated region （3′-UTR） of the only predicted gene, Roc5 （Rice outermost cell-specific）. The expression level of Roc5 is significantly higher in the rl（t） mutant than in the wild-type. Using RNAi and overexpression analysis, we found that the expression level of Roc5 correlated with LRI and leaf bulliform area, and wasalso associated with leaf abaxial or adaxial rolling. These results confirmed that Roc5 controls leaf rolling in a dosagedependent manner. Bioinformatics analysis revealed a conserved 17-nt sequence （called the GU-rich element） in the 3′-UTR of HD-GL2 （Homeodomain-Glabra2） family genes including Roc5. Based on the model of this element in regulating mRNA stability in mammals, we speculate that the single nucleotide change in this element accounts for the higher expression level of Roc5 in the rl（t） mutant compared to the wild-type, which ultimately leads to adaxial rolling of the leaf. This discovery further enhances our knowledge of the molecular mechanisms underlying leaf rolling in rice.