Daunomycin binding to detergent micelles: A model system for evaluating the hydrophobic contribution to drug-DNA interactions

The interaction of daunomycin with sodium dodecyl sulfate and Triton X-100 micelles was investigated as a model for the hydrophobic contribution to the free energy of DNA intercalation reactions. Measurements of visible absorbance, fluorescence lifetime, steady-state fluorescence emission intensity, and fluorescence anisotropy indicate that the anthraquinone ring partitions into the hydrophobic micelle interior. Fluorescence quenching experiments using both steady-state and lifetime measurements demonstrate reduced accessibility of daunomycin in sodium dodecyl sulfate micelles to the anionic quencher iodide and to the neutral quencher acrylamide. Quenching of daunomycin fluorescence by iodide in Triton X-100 micelles was similar to that seen with free daunomycin. Studies of the energetics of the interaction of daunomycin with micelles by fluorescence and absorbance titration methods and by isothermal titration calorimetry in the presence of excess micelles revealed that association with sodium dodecyl sulfate and Triton X-100 micelles is driven by a large negative enthalpy. Association of the drug with both types of micelles also has a favorable entropic contribution, which is larger in magnitude for Triton X-100 micelles than for sodium dodecyl sulfate micelles.

Stable ordered mesoporous silica materials templated by high-temperature stable surfactant micelle in alkaline media

Ordered hexagonal mesoporous silica material (JLU-30) has been successfully synthesized in alkaline media at high temperature (> 160 degreesC, using cationic (1,3-dimethyl-2-imidazolidin-2-ylidene)hexadecylmethyl-ammonium bromide (DIHAB) as a template, and characterized with X-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen adsorption-desorption isotherms, differential thermal analysis (DTA), and thermogravimetric analysis (TG), as well as Al-27 and Si-29 nuclear magnetic resonance (NMR) spectroscopy. Mesoporous JLU-30 shows much higher hydrothermal stability than MCM-41. Si-29 NMR spectra indicate that the pore walls of JLU-30 samples synthesized at high temperature (160 degreesC) are fully condensed, giving a Q(4)/Q(3) ratio as high as 6.2. In contrast, MCM-41 synthesized at relatively low temperature (100 degreesC) shows the Q(4)/Q(3) + Q(2) ratio at 1.1. Such unique structural feature might be responsible for the observed highly hydrothermal stability of the mesoporous silica materials (JLU-30).

Realization of MMI power splitter by UV-light imprinting technique using hybrid sol-gel SiO2 materials

An efficient fabrication scheme of buried ridge waveguide devices is demonstrated by UV-light imprinting technique using organic-in organic hybrid sol-gel Zr-doped SiO2 materials. The refractive indices of a guiding layer and a cladding layer for the buried ridge waveguide structure are 1.537 and 1.492 measured at 1550 nm, respectively. The tested results show more circular mode profiles clue to existence of the cladding layer. A buried ridge single-mode waveguide operating at 1550 nm has a low propagation loss (0.088 dB/cm) and the 1 x 2 MMI power splitter exhibits uniform outputs, with a very low splitting loss of 0.029 dB at 1549 nm.

水稻同源四倍体三系法杂种优势利用研究

水稻是重要的粮食作物，其产量的增加和品质的改良都是关系国计民生的大事。就我国现阶段的国情而言，水稻产量在现有水平上稳步提升仍是未来十几年甚至几十年农业生产最重要的目标之一。尽管根据“超级杂交水稻育种”的战略设想和水稻育种实践，通过不断地改进育种技术可望在更高的产量水平上进行水稻杂种优势利用，在稻属植物内还具有很大的产量潜力可以挖掘。然而，仅仅从现有的种质基础出发，要更大幅度提高水稻单产，实现“超级杂交稻”的目标也存在一些困难：现有的推广品种是二倍体，尽管种类众多，但是其基因组的来源相对单一；同时，水稻基因组DNA含量也是作物中最少的，基因组内寻求开发潜力有一定困难；水稻作为C3植物，光合利用效率不高也是制约水稻产量提高的因素之一。因此，寻求常规手段以外的技术突破或者方法创新，是实现“超级杂交稻”的目标的迫切需求。本研究利用秋水仙素能抑制细胞分裂中纺锤丝的收缩、使细胞染色体加倍的作用，对水稻幼穗诱导的愈伤组织细胞进行加倍，并分化出再生植株；创制出水稻同源四倍体新的种质材料，在此基础上选育水稻同源四倍体雄性不育三系材料，并实现水稻同源四倍体的三系配套，开展水稻同源四倍体杂种优势利用和四倍体杂交水稻选育研究，建立水稻同源四倍体杂种优势利用的新技术体系。这不仅有助于倍性水平杂种优势的开拓和利用，同时也将为我国新世纪“超级稻”育种研究开辟一条新的技术途径。 水稻幼穗诱导愈伤组织并分化成苗是一项成熟、简单的组织培养技术。本研究以普通二倍体水稻亲本为材料，用秋水仙素进行水稻的多倍体化诱导，创制同源四倍体水稻三系亲本材料并对其进行鉴定。多倍体化以秋水仙素诱导的愈伤组织培养为基础，研究不同秋水仙素浓度梯度和愈伤组织诱导培养基组合对诱导四倍体植株的影响。结果表明在MS+2,4 D 1.0mg/L+ KT0.2mg/L+ IAA0.2mg/L 和500mg/L的秋水仙素处理下，水稻愈伤组织染色体加倍（有最高的效率）效果较好，平均加倍频率可达25.26%，其中，材料CDR22和IR26诱导较易成功，加倍频率分别达到75%和26.5%；相对材料94109 1.3%加倍频率和冈46B 10.8%加倍频率，诱导率差异极显著。 对水稻四倍体材料进行了形态学鉴定结果表明，与二倍体水稻对照相比其株高、穗长、花粉育性等主要农艺性状，确定四倍体材料在穗长和千粒重两方面极显著提高，种子的长度和宽度也显著增长。对花粉育性鉴定，确认水稻四倍体不育系材料仍为不育，保持系材料自交和杂交可育，恢复系材料自交和杂交可育。对四倍体材料进行细胞形态、染色体数目等方面进行细胞学鉴定，经核型分析表明水稻四倍体材料具有48条染色体，是二倍体水稻的两倍。水稻四倍体材料根尖分生组织细胞与二倍体的根尖分生组织细胞相比，细胞体积、细胞核和核仁显著增大。四倍体三系材料在细胞有丝分裂中期均可规则排列在赤道板，并能均等地移向两极；后期观察中没有发现染色体分离滞后现象，分裂末期细胞能够形成大小相对均一的子细胞。水稻同源四倍体三系材料细胞分裂未见异常，植株生长发育正常。 从1996年至2006年，针对结实率、有效分蘖、着粒数和穗长等主要农艺性状，通过系谱选育的方法，对培育的同源四倍体水稻亲本材料进行了连续选择和改良，取得较好成效。表现为结实率的改良效果极佳，所有改良材料的平均结实率均呈上升趋势，如D237（29.70％→72.70％）、DTB（19.55％→53.21％）等。有效分蘖总体呈现上升趋势，但在不同的年份，如1998和2002存在较大的负向波动。部分材料改良效果明显，如D19B（5.87→13.50）、D什香 (7.00→12.00)等；同时一些材料如DTB和D明恢63虽然总体略有提高，但在不同的年份波动很大，因此存在较大改良阻力，原因还有待进一步研究。着粒数的改良上升趋势比较显著，除保持系的DTB之外，其余材料的平均着粒数有显著提高。穗长的改良阻力较大，虽然不同材料总体上有所提高，但效果并不显著，并且不同年份有较大负向波动（2001）。此外还对株高、剑叶长等性状也进行了选择，但效果不显著，原因有待进一步提高。同源四倍体材料产量相关性状遗传改良幅度不一致，保持系和恢复系间的遗传改良效果也存在差异。这为同源四倍体水稻的进一步利用打下了良好的基础。 籼稻和粳稻亚种间杂交及杂种优势利用的主要障碍就是其低的结实率。而同源四倍体杂交水稻的研究为提高杂交水稻的杂种优势利用创造了新的途径。本研究通过随机区组设计方案，挑选性状优良的二倍体水稻材料，包括雄性不育系，保持系和恢复系进行秋水仙素诱导加倍，从而获得同源四倍体水稻对应的三系材料。利用选育的优良水稻同源四倍体三系材料，配制7个杂交组合，杂交F1代与其恢复系亲本进行比较，用于计算超亲优势（HB）；而杂交F1代与生产上大面积推广的二倍体杂交品种汕优63进行比较，用于计算杂种优势。结果显示，同源四倍体杂交水稻的超亲优势表现为：每株有效穗变化幅度为1.4%至105.9%，总粒数为0.5%至74.3%，每穗实粒数为17.6%至255.7%，结实率为9.6%至130.4%。这些农艺性状的改良使得这7个杂种F1的理论产量的超亲优势高达64.8%至672.7%。小区试验中四倍体杂交水稻组合T461A/T4002和T461A/T4193分别比二倍体对照汕优63提高46.3%和38.3%以上，除一个品种以外所有品种产量均接近或高于汕优63的产量。同源四倍体水稻强大的杂种优势表明，亚种间杂交育性低的问题可通过四倍体化及强化选择来解决。此外，同源四倍体杂交水稻器官的巨大性也是其产量提高的有利因素，水稻同源四倍体三系杂种优势利用研究具有一定的理论价值和商业生产潜力。 Rice is one of the major food crops, the improvement of the production and quality of it is an important thing related to the people's livelihood. On China's current national conditions, steadily increase of the rice yield based on the current level is still one of the most important goals in the next decade or even decades of agricultural production. According to the "super hybrid rice breeding" the strategic and rice breeding practice, improvement of the use of hybrid rice heterosis through continuous improvements in breeding technology is expected to get a higher level of rice yield, there are also a great yield potential can be exploited. However, there are also some difficulties to increase rice yield obviously and implement the goal of "super hybrid rice" based on the existing germplasm: Rice varieties in promotion are diploid, although there are many varieties, but their genome are from a comparatively single source; Meanwhile, the rice genome DNA are the least among the crops, it is difficult to exploit the development potential within the genome; Rice as C3 plants, photosynthetic efficiency is not high, it is one of the factors constraint rice yield. Therefore, seeking technological breakthroughs or innovative methods different from conventional means is the urgent needs to reach the target of "super hybrid rice". Using colchicine inhibit spindle contraction during cell division, double the cell chromosome, we induced callus cells from rice panicle to be doubled, and differentiated regeneration; we created a new autotetraploid rice germplasm material, and on that basis we bred male sterility three line autotetraploid rice materials, and the achieved the three line rice autotetraploid matchmaking, researched in autotetraploid rice heterosis usage and tetraploid hybrid rice breeding, constituted a new technology system of autotetraploid hybrid rice heterosis utilization. This not only helps the tetraploid rice heterosis exploration and use, but also inaugurates a new technical means for China in the new century "super rice" breeding research. We chose ordinary diploid rice as materials, using colchicine to induce the polyploidization, created the autotetraploid rice three-line materials and identified them. The polyploidization was based on the colchicine-induced callus tissue culture, and we experimented different colchicine concentrations and culture mediums to induce tetraploid plants, confirmed that the optimal concentration for inducement was 500 mg/L, the average induce rate was 25.26 %. Among all the materials, CDR22 and IR26 had higher induced rate; in contrary, 94109 and GANG46B had lower induced rate, the difference was significant. Autotetraploid materials was identified of both morphological and cytological, compared plant height, length of pollen sterility, and other major agronomic traits with a diploid rice as the control plant, identified that the autotetraploid materials had very significant advantages in ear length and thousand-grain weight, as well as the size of the seeds. Cytology identification included observation of the cell morphology, the number of chromosomes, and karyotype analysis on the autotetraploid materials confirmed that their chromosome number was 48, twice of the diploid rice. Mitoses in the three lines were common: chromosomes arrayed normally in metaphase and separated balanced into the two poles, chromosome moved without lagging in anaphase and daughter cells normally formed in telophase except one. It has been proved that tetraploid rice has normal meiosis as their diploid relatives, which usually including series of sub-phases as interphase, prophase I (five sub-phases), prophase II, metaphase I, II, anaphase I, II and telophase I, II. However, abnormal phenomena, such as formation of tetravalent, trivalent and univalent, chromosome lagging and so on, which would finally block meiosis. Configurations of chromosome in metaphaseⅠwere versatile in structure and form accept the bivalent. That condition varied in different strain, suggesting more complex paring configurations and more versatile genetic characters in tetraploid rice. All these abnormalities in meiosis contributed to low fertility of gamete and might consequently resulted in low seed setting. Successive selection and improvement on seed set, productive tiller per plant, total grains per panicle, panicle length and so on had been carried out from 1996 to 2006. The raise of seed sets was significant in both restorers and maintainers. Seed sets of some strains were improved more significantly than others, for example D237（29.70％→72.70％）、DTB（19.55％→53.21％）and et al.. Productive tiller per plant was improved to some extant. The tendency of improvement was rising on the whole but changed in some years such as 1998 and 2002. Part of the stains increased greatly, such as D19B（5.87→13.50）、Dshixiang (7.00→12.00) and so on, but some strains including DTB and Dminghui63 only increased little and decreased in some years by unknown reason. Total grains per panicle increased significantly and all strains except DTB increased. Improvement of panicle length termed to be hard. Different strains showed different capacities for improvement and floating existed in different years for example 2001. It has been proved that other agronomical traits including plant length, flag leaf length and so on could be improved but not significantly by selection also. In a word, agronomical traits could be raised by successive selection that is prerequisite for further utility of autotetraploid rice. Poor fertility is the main barrier for utilizing heterosis between the two rice (Oryza stiva L.) sub-species, indica and japonica. Recently, the development of autotetraploid hybrids (2n=4x=48) has been suggested as a new method for increasing heterosis in hybrid rice. Using standard experimental protocols, the elite diploid rice male sterile, maintainer, and restorer lines were colchine-doubled and autotetraploid counterparts were obtained. Seven resulting hybrids were analyzed for heterobeltiosis (HB), where the F1 was compared to the male parent, and the degree of heterosis, where the F1 was compared to the diploid commercial hybrid, Shanyou 63. The HB among the autotetraploid hybrids ranged from 1.4 to 105.9% for the productive panicles per plant, 0.5 to 74.3% for total kernels per panicle, 17.6 to 255.7% for filled kernels per panicle, and 9.6 to 130.4% for seed set. Improvements in these yield components resulted in the HB for kernel yield ranging from 64.8 to 672.7% among the seven hybrids. Hybrids T461A/T4002 and T461A/T4193 yielded 46.3 and 38.3% more, respectively than Shanyou 63, and all other hybrids but one yielded the same or more than Shanyou 63. The high heterosis for yield suggests that hybrid sterility between two rice sub-species may be overcome by using tetraploid lines followed by intensive selection. Also, the gigantic features of the autotetraploid hybrids may establish a plant structure able to support the higher yield.

Optical Analysis of Hg2+ Ions by Oligonucleotide–Gold-Nanoparticle Hybrids and DNA-Based Machines

Zwei verschiedene optische Methoden für die Analyse von Hg2+-Ionen, die auf der Bildung von Thymin-Hg2+-Komplexen beruhen, werden vorgestellt. Bei diesen Methoden werden die Hg2+-Ionen mithilfe aggregierter Goldnanopartikel und einer auf der DNA-Chemie basierenden Maschine (siehe Schema) analysiert.

Synthesis and Characterization of Urea Bridged Hybrid Periodic Mesoporous Organosilica Materials

Urea bridged organic-inorganic hybrid mesoporous SiO2 materials (U-BSQMs) were synthesized through a sol-gel procedure by co-condensation of bis(triethoxysilyl propyl) urea (BSPU) under basic conditions using cetyltrimethylammonium bromide (CTAB) as organic template. X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed the mesoporous structure of the sample. Fourier-transform infrared spectroscopy (FT-IR), solid state CP-MAS NMR spectroscopy of Si-29 (Si-29, CP-MAS NMR) and C-13 (C-13 CP NMR) indicated that most of the Si-C bonds are unbroken during the synthesis process.

Construction of hollow DNA/PLL microcapsule as a dual carrier for controlled delivery of DNA and drug

DNA/poly-L-lysine (PLL) capsules were constructed through a layer-by-layer (LbL) self-assembly of DNA and PLL on CaCO3 microparticles, and then used as dual carriers for DNA and drug after dissolution of carbonate cores. The permeability of DNA/PLL microcapsules was investigated with fluorescence probes with different molecular weights by confocal microscopy. The result revealed that the fluorescence probes were able to penetrate the capsule walls even its molecular weight up to 150 kDa. The resultant capsules were used to load drug model molecules-fluorescein isothiocyanate (FITC)-dextran (4 kDa) via spontaneous deposition mechanism.

A simple and sensitive colorimetric pH meter based on DNA conformational switch and gold nanoparticle aggregation

A simple and rapid colorimetric pH meter has been developed based on the conformational switch of i-motif DNA and non-crosslinking AuNP aggregation, the average accuracy of the nano-meter was found to be +/- 0.04 pH unit across the physiological operating range.

Formation of reversible shell cross-linked micelles from the biodegradable amphiphilic diblock copolymer poly(L-cysteine)-block-poly(L-lactide)

A novel biodegradable diblock copolymer, poly(L-cysteine)-b-Poly(L-lactide) (PLC-b-PLLA), was synthesized by ring-opening polymerization (ROP) of N-carboxyanhydride of beta-benzyloxycarbonyl-L-Cysteine (ZLC-NCA) with amino-terminated Poly(L-lactide) (NH2-PLLA) as a macroinitiator in a convenient way. The diblock copolymer and its precursor were characterized by H-1 NMR, Fourier transform infrared (FT-IR), gel permeation chromatography (GPC), and X-ray photoelectron spectroscopy (XPS) measurements. The length of each block polymer could be tailored by molecular design and the ratios of feeding monomers.

Novel pH- and temperature-responsive block copolymers with tunable pH-responsive range

A series of novel pH- and temperature-responsive diblock copolymers composed of poly(N-isopropylacrylamide) (PNIPAM) and poly[(L-glutamic acid)-co-(gamma-benzyl L-glutamate)] [P(GA-co-BLG)] were prepared. The influence of hydrophobic benzyl groups on the phase transition of the copolymers was studied for the first time. With increasing BLG content in P(GA-co-BLG) block, the thermal phase transition of the diblock copolymer became sharper at a designated pH and the critical curve of phase diagram of the diblock copolymer shifted to a higher pH region.

Hydration of drug-DNA complexes: Greater water uptake for adriamycin compared to daunomycin

Water is an integral part of DNA, and the conserved water molecules at the binding sites can modulate drug binding to DNA or protein. We report here that anthracycline antitumor antibiotics, adriamycin (AM) and daunomycin (DM), binding to DNA is accompanied by different hydration changes, with AM binding resulting in the uptake of about twice as many water molecules as DM. These results indicate that water is playing an important role in drug binding to DNA.

Self-assembly of lambda-DNA networks/Ag nanoparticles: Hybrid architecture and active-SERS substrate

In this article, highly rough and stable surface enhanced Raman scattering (SERS)-active substrates had been fabricated by a facile layer by-layer technique. Unique lambda-DNA networks and CTAB capped silver nanoparticles (AgNP) were alternatively self-assembled on the charged mica surface until a desirable number of bilayers were reached. The as-prepared hybrid architectures were characterized by UV-vis spectroscopy, tapping mode atomic force microscopy (AFM) and confocal Raman microscopy, respectively.

Ethanol-induced formation of silver nanoparticle aggregates for highly active SERS substrates and application in DNA detection

A controllable silver nanoparticle aggregate system has been synthesized by adding different amounts of ethanol to cetyltrimethylammonium bromide (CTAB) capped silver nanoparticles (Ag-nps), which could be used as highly efficient surface-enhanced Raman scattering (SERS) active substrates. This ethanol-induced aggregation can be attributed to preferential dissolution of CTAB into ethanol, which leads a partial removal of the protective CTAB layer on Ag-nps. The optical and morphological properties of these aggregates under various volumes of ethanol were explored via UV-vis spectroscopy and atomic force microscopy.

Hollow DNA/PLL microcapsules with tunable degradation property as efficient dual drug delivery vehicles by alpha-chymotrypsin degradation

Hollow deoxyribonucleic acid (DNA)/poly-L-lysine (PLL) capsules were successfully fabricated through a layer-by-layer (LbL) self-assembly of DNA and PLL on porous CaCO3 microparticles, followed by removal of templates with ethylenediamine tetraacetic acid disodium salt (EDTA). The enzymatic degradation of the capsules in the presence of alpha-chymotrypsin was explored. The higher the enzyme concentration, the higher is the degradation rate of hollow capsules. in addition, glutaric dialdehyde (GA) cross-linking was found to be another way to manipulate degradation rate of hollow capsules.