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991.
FENG ShuJie MA JunHong LIN Fei WANG Ling PAN QingHua 《科学通报(英文版)》2007,52(24):3346-3354
Magnaporthe oryzae is a model for plant pathogenic filamentous fungi. We have assembled a simple sequence repeat (SSR)-based physical map of the species, using in silico sequence data. A set of 120 SSR markers was developed from the genomic sequence of the reference isolate 70-15. These markers were readily amplified from the genomic DNA of other isolates, and high levels of allelic variation characterised the parental isolates of the two crosses tested. All the markers were locatable to one of the seven M. oryzae chromosomes. An SSR-based physical in silico map was constructed, and pre-existing SSR and RFLP loci were integrated into the map, along with 23 Avr (avirulence) genes and two other genes of importance to the plant/pathogen interaction. This map provides a platform for population genetics and functional genomics studies in the model pathogen, and even in other evolu- tionally related pathogens. 相似文献
992.
WANG YongSheng SUN HongMei TAO XuePing SHEN Qi ZHANG Yong 《科学通报(英文版)》2007,52(23):3193-3199
The reaction of anhydrous FeBr2 with two equivalents of anionic N-heterocyclic carbene (NaL1 and NaL2), which are generated in situ by the reaction of the corresponding salt [4-R-C6H4COCH2{CH- (NCHCHNiPr)}Br] (R = OCH3, H2L1Br, 1; R = F, H2L2Br, 2) with two equivalents of NaN(SiMe3)2, affords bis-ligand Fe(II) complexes of L12Fe (3) and L22Fe (4) in high yield, respectively. Attempt to synthesize mono-ligand Fe(II) bromide by the 1:1 molar ratio of NaL to FeBr2 is unsuccessful, and the same com- plexes of 3 and 4 were obtained. Both 3 and 4 have been depicted by elemental analysis and X-ray structure determination. Preliminary studies show that both 3 and 4 can be used as single-component catalyst for the ring-opening polymerization of ε-caprolactone, and the catalytic activity of 3 is higher than that of 4. 相似文献
993.
LIN Yi SHEN XinCheng WANG JingJing BAO Lei ZHANG ZhiLing PANG DaiWen 《科学通报(英文版)》2007,52(23):3189-3192
Based on tapping mode AFM imaging, a method was demonstrated to evaluate compression elasticity of single double-stranded DNA (dsDNA) molecules in the force region. With images under ambient conditions, Young's moduli of dsDNA in compression were calculated. Results demonstrated that Young's moduli of dsDNA can be simply deduced according to the proposed model. The method can also be used to evaluate the compression elasticity of similar soft nanomaterials. 相似文献
994.
Using a newly installed system on the 25 m telescope of Urumqi Observatory, we searched for H20 maser emission towards 84 IRAS sources including young stellar objects (YSOs) and candidates for OFUIR stars. Water masers were detected in four star formation regions and one envelope of late type of stars for the first time. New water maser components were measured in two sources. In a maser source with no water maser emission detected six years ago, strong maser emission was found at different velocities, showing that there was a new explosion of water maser in this source. 相似文献
995.
YANG KeFang HUANG YingJuan DONG JinYong 《科学通报(英文版)》2007,52(2):181-187
The copolymerization of propylene and 5-hexenyl-9-borabicyclo[3.3.1]nonane (5-hexenyl-9-BBN) has been conducted with an MgCl2/TiCl4 catalyst intercalated in an organically modified montmorillonite (OMMT) with triethylaluminum (AlEt3) cocatalyst and diphenyldimethoxysilane (DDS) external donor. This polymerization process simultaneously results in both the exfoliation of MMT layers to realize the preparation of polypropylene (PP)/MMT nanocomposites and the implantation of reactive borane groups in the formed PP matrix. The polymer-borne borane groups have been able to undergo an effi-cient hydrolysis process under very mild reaction conditions (40℃, 3 h, in THF), introducing hydroxy groups into PP without sacrificing the polymerization-formed nanocomposite structure (the exfoliation of MMT). The resultant hydroxyl-functionalized PP/MMT nanocomposites exhibit enhanced structural stability against processing compared with those based on unfunctionalized PP matrix. 相似文献
996.
DU JinFeng LI Ying ZHANG Qi YAO XiaoJun 《科学通报(英文版)》2007,52(2):200-204
The presence of several high affinity binding sites on human serum albumin (HSA) makes it a possible target for many drugs. This study is designed to examine the effect of aloe-emodin on HSA by fluo-rescence, CD spectroscopy and molecular modeling. The results of fluorescence measurements sug-gested that the hydrophobic interaction was the predominant intermolecular force stabilizing the AE-HSA complex, which was in good agreement with the result of molecular modeling study. And the enthalpy change ΔH0 and the entropy change ΔS0 were calculated to be -7.041 kJ·mol-1 and 76.619 J·mol-1·K-1 according to the Van't Hoff equation. The alterations of protein secondary structure in the presence of AE in aqueous solution were quantitatively calculated from CD spectra, and the content of α-helices obviously increased. 相似文献
997.
WANG FangHai ZHANG GuRen WEN RuiZhen HE GuoFeng 《科学通报(英文版)》2007,52(2):205-208
In order to understand the composition and quantitative variation of ecdysteriods in the larvae of Opogona sacchari (Bojer), a invasive alien pest, we analyzed the larval ecdysteroid composition and titers in this pest. The main component of ecdysteriods in the larvae of O. sacchari is 20-hydroxyecdysone, and also there is a little 26-hydroxyecdysone. The titer of ecdysteriods in the larvae from the 1st instar to the 7th instar was gotten higher gradually compared on ng ecdyster-oid/larva, but no regularity could be found about the titer if compared on ng ecdysteroid/g avoirdupois. There was only one peak of ecdysteroids (0.5475 ng/larva) showed at day 2 during the developmental time of the 6th instar larvae. However, there were two peaks appearing during the developmental time of the 7th instar larvae , one peak (0.29415 ng/larva) at day 3, another (0.214 ng/larva) at day 5. 相似文献
998.
DENG Jun WU ZhiJun HUANG ChengJie FENG Wei LI LiGuang 《科学通报(英文版)》2007,52(2):277-283
Auto-ignition characteristics of high-pressure diesel spray in the controllable active thermo-atmos-phere (CATA) were studied with a high-speed camera video system. Multi-point autoignition phe-nomenon of diesel spray in the CATA was observed and the influence factors of the autoignition were analyzed. The stabilization mechanisms of the spray flame in different coflow temperatures were also discussed. The stabilization of the flames was controlled by different factors: autoignition phenomenon in low coflow temperature and flame spread in high coflow temperature. The test results also show that the autoignition delay depends strongly on the coflow temperature and has nonlinear relationship with the temperature. Autoignition delay decreases by almost 10 ms from 16.9 to 7.1 ms when the coflow temperature increases from 996 to 1048 K and only 4 ms from 1048 to 1101 K. The injection parameters in terms of nozzle diameter, injection pressure and pump speed, have some effects on autoignition delay while these effects depend on the coflow temperature. The significant effect lies in low coflow temperature. The injection parameters influence the autoignition delay because it can shorten the physical delay by improving the spray quality and enlarging the spray angle or penetration rate to im-prove mixture quality. 相似文献
999.
SONG Yan PENG DanLing LI XiaoLan ZHANG Yi KANG Jing QU Zhe DING YuLong 《科学通报(英文版)》2007,52(3):352-357
The current work investigated the neural correlates of visual perceptual learning in grating orientation discrimination by recording event-related potentials (ERPs) from human adults. Subjects were trained with a discrimination task of grating orientation in three consecutive training sessions within 2 h. While reaction times (RTs) were shortened gradually across training sessions, the N1 was decreased and the P2 was increased over the parietal and occipital areas. A broadly distributed P3 was increased along with more practices. In addition, the time course of learning reflected in the P2 and P3 amplitudes was in line with the changes of reaction times and exhibited a stable level during later training. The impli- cations of these results to the neural mechanisms subserving perceptual learning were discussed. 相似文献
1000.
PENG XiaoTong ZHOU HuaiYang WU ZhiJun JIANG Lei TANG Song YAO HuiQiang 《科学通报(英文版)》2007,52(3):367-379
Microbial mats in two hot springs in South China were sampled for the research of mineralization of microbes and its mechanism by the methods of geology and modern biology. The results show that hot spring microbes have the key capability for enrichment of Si, Al, Fe, Ca and other elements, and the microbes are also crucial for the formation of SiO2, CaCO3, clay and so on. The extracellular polymeric substances (EPS) play important roles in the process of mineralization of hot spring microbes, which mainly takes place in the layer of EPS outside cell wall or sheath of cyanobacteria. The sheath outside cell wall, which keeps the normal metabolism of cyanobacteria during the process of mineralization on its surface, is also considerable for the biomineralization of cyanobacteria. According to structure and mineralization characteristics of two microbial mats, the process of mineralization can be divided into three stages, namely, early surface mineralization, middle degradation mineralization, and late des- quamation of mineral. The above conclusions are significant for comprehension of the process of mineralization, the process of deposition and the preservation of microfossil in modern and ancient extreme environments. 相似文献