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31.
为研究北柴胡种子内生菌的群落结构与多样性.采用Illumina Miseq高通量测序技术,分别对山西(BC_1)、黑龙江(BC_2)、河北(BC_3)和内蒙古(BC_4)的四个产地(4份)北柴胡种子的16S RNA V3-V4区和ITS1区扩增片段进行测序,并对内生细菌和内生真菌群落结构和多样性进行分析.结果表明,BC... 相似文献
32.
古人口学研究包含对人口学静态参数和动态参数的研究,本文对江苏兴化蒋庄遗址良渚文化墓地进行了性别、年龄结构的分析和生育水平的估计,后者采用的是用n30+/n5+估算粗出生率的方法。蒋庄人口的性别比是105,属于正常范围。模型拟合研究发现蒋庄人口的死亡年龄结构接近正态分布,这种现象可能与婴幼儿统计漏查、成人年龄鉴定中存在的问题和对"老年"标准的定义有关。通过估算粗出生率并将蒋庄样本和其他新石器时代人骨样本进行粗出生率的对比,发现蒋庄人口的生育水平较高,可能与其环境优渥、文明进步有关。研究还表明,对新方法的尝试和对人骨样本代表性的重视是推动古人口学进步的关键。 相似文献
33.
The Light-harvesting Chlorophyll a/b-Protein Complex of Chlamydomonas reinhardii 总被引:5,自引:5,他引:5 下载免费PDF全文
The molecular organization of chlorophyll in Chlamydomonas reinhardii has been shown to be essentially similar to that in higher plants. Some 50% of the chlorophyll in Chlamydomonas reinhardii chloroplast membranes has been shown to be located in a chlorophyll a/b-protein complex. The complex was isolated in a homogeneous form by hydroxylapatite chromatography of sodium dodecyl sulfate extracts of the chloroplast membranes. Its absorption spectrum exhibits two maxima in the red region at 670 and 652 nm due to the presence of equimolar quantities of chlorophylls a and b in the complex. Preparations of the chlorophyll-protein also contain some of each of the carotenoids observed in the intact chloroplast membrane, but not in the same proportions. The native complex (S value = 2.3S) exhibits a molecular weight of 28,000 ± 2,000 on calibrated sodium dodecyl sulfate-polyacrylamide gel electrophoresis. However, on the basis of its amino acid composition and other data a more probable molecular weight of about 35,000 was calculated. Each 35,000 dalton unit contains three chlorophyll a and three chlorophyll b molecules, and on the average one carotenoid molecule conjugated with probably a single polypeptide of 29,000 daltons. Comparison of spectral and biochemical characteristics demonstrates that this algal chlorophyll-protein is homologous to the previously described major light-harvesting chlorophyll a/b-protein of higher plants. It is anticipated that the Chlamydomonas complex functions solely in a light-harvesting capacity in analogy to the function determined for the higher plant component. 相似文献
34.
Manuel Avilés María Teresa Castells Irene Abascal José Angel Martínez-Menárguez Petr Dráber Frederick W. K. Kan J. Ballesta 《Cell and tissue research》1999,295(2):269-277
Carbohydrate residues contained in the zona pellucida play a key role in the process of sperm-egg interaction. In vitro fertilization experiments have shown that a specific monoclonal antibody against GalNAcş,4Galş,4 disaccharide inhibits fertilization in mice. In the present study, the ultrastructural cytochemical localization of GalNAc residues and the GalNAcş,4Galş,4 disaccharide was carried out in ovarian and postovulatory oocytes by using lectin-gold cytochemistry and immunocytochemistry. Plant lectins SBA and DBA showed an affinity for the entire zona pellucida matrix of ovarian oocytes throughout the follicular maturation; however, immunoreactivity for GalNAcş,4Galş,4 disaccharide was not detected in ovarian oocytes at the earliest stages of follicular development but was found to be associated with the inner region of the zona matrix at the trilaminar primary follicle stage. The Golgi apparatus, vesicular aggregates, and cortical granules of the oocyte were intensely labeled by SBA and DBA throughout follicular development. Immunoreactivity to GalNAcş,4Galş,4 disaccharide was first observed in the Golgi apparatus and vesicular aggregates in trilaminar primary follicles. No immunoreactivity was observed in the cortical granules. In postovulatory oocytes, results were similar to those observed in ovarian oocytes. Our results thus suggest that (1) GalNAcş,4Galş,4 disaccharide residues are present only in the inner region of the zona pellucida and, therefore, might be involved in sperm penetration through the zona pellucida, (2) the inner and outer regions of the zona pellucida contain different oligosaccharide chains, (3) the vesicular aggregates detected in the oocyte could represent an intermediate step in the secretory pathway of zona pellucida glycoproteins and might be involved in the formation of cortical granules. 相似文献
35.
N Kan S Yamasaki T Harada K Satoh Y Ichinose Y Moriguchi H Kodama K Ohgaki 《Human cell》1992,5(3):236-242
Among several approaches to augment the therapeutic effect of adoptive immunotherapy, we focused the antitumor synergy between transferred killer cells and host's fresh lymphocytes. Immunotherapy models using murine tumors or clinical experiments revealed that preadministration of immunostimulator such as OK-432, followed by chemotherapeutic agents such as cyclophosphamide, can induce host's non-cytotoxic fresh lymphocytes that act synergistically with cultured killer cells against autologous tumor cells. Immuno-chemo-lymphocytotherapy (a sequential treatment with OK-432, chemotherapy and adoptive immunotherapy) is useful to treat the patients with advanced cancer even if the number of transferred lymphocytes is limited. 相似文献
36.
J. G. M. van Nistelrooy J. M. van den Brink J. A. L. van Kan R. F. M. van Gorcom M. A. de Waard 《Molecular & general genetics : MGG》1996,250(6):725-733
TheCYP51 gene encoding eburicol 14-demethylase (P45014DM) was cloned from a genomic library of the filamentous fungal plant pathogenPenicillium italicum, by heterologous hybridisation with the corresponding gene encoding lanosterol 14-demethylase from the yeastCandida tropicalis. The nucleotide sequence of a 1739-bp genomic fragment and the corresponding cDNA clone comprises an open reading frame (ORF) of 1545 bp, encoding a protein of 515 amino acids with a predicted molecular mass of 57.3 kDa. The ORF is interrupted by three introns of 60, 72 and 62 bp. The C-terminal part of the protein includes a characteristic haem-binding domain, HR2, common to all P450 genes. The deducedP. italicum P45014DM protein and the P45014DM proteins fromCandida albicans, C. tropicalis andSaccharomyces cerevisiae share 47.2, 47.0 and 45.8% amino acid sequence identity. Therefore, the cloned gene is classified as a member of theCYP51 family. Multiple copies of a genomic DNA fragment ofP. italicum containing the cloned P450 gene were introduced intoAspergillus niger by transformation. Transformants were significantly less sensitive to fungicides which inhibit P45014DM activity, indicating that the cloned gene encodes a functional eburicol 14-demethylase. 相似文献
37.
Replicating rather than nonreplicating adenovirus-human immunodeficiency virus recombinant vaccines are better at eliciting potent cellular immunity and priming high-titer antibodies 总被引:3,自引:0,他引:3 下载免费PDF全文
Peng B Wang LR Gómez-Román VR Davis-Warren A Montefiori DC Kalyanaraman VS Venzon D Zhao J Kan E Rowell TJ Murthy KK Srivastava I Barnett SW Robert-Guroff M 《Journal of virology》2005,79(16):10200-10209
A major challenge in combating the human immunodeficiency virus (HIV) epidemic is the development of vaccines capable of inducing potent, persistent cellular immunity and broadly reactive neutralizing antibody responses to HIV type 1 (HIV-1). We report here the results of a preclinical trial using the chimpanzee model to investigate a combination vaccine strategy involving sequential priming immunizations with different serotypes of adenovirus (Ad)/HIV-1(MN)env/rev recombinants and boosting with an HIV envelope subunit protein, oligomeric HIV(SF162) gp140deltaV2. The immunogenicities of replicating and nonreplicating Ad/HIV-1(MN)env/rev recombinants were compared. Replicating Ad/HIV recombinants were better at eliciting HIV-specific cellular immune responses and better at priming humoral immunity against HIV than nonreplicating Ad-HIV recombinants carrying the same gene insert. Enhanced cellular immunity was manifested by a greater frequency of HIV envelope-specific gamma interferon-secreting peripheral blood lymphocytes and better priming of T-cell proliferative responses. Enhanced humoral immunity was seen in higher anti-envelope binding and neutralizing antibody titers and better induction of antibody-dependent cellular cytotoxicity. More animals primed with replicating Ad recombinants mounted neutralizing antibodies against heterologous R5 viruses after one or two booster immunizations with the mismatched oligomeric HIV-1(SF162) gp140deltaV2 protein. These results support continued development of the replicating Ad-HIV recombinant vaccine approach and suggest that the use of replicating vectors for other vaccines may prove fruitful. 相似文献
38.
39.
Jiangbin Zhang Moritz H. Futscher Vincent Lami Felix U. Kosasih Changsoon Cho Qinying Gu Aditya Sadhanala Andrew J. Pearson Bin Kan Giorgio Divitini Xiangjian Wan Dan Credgington Neil C. Greenham Yongsheng Chen Caterina Ducati Bruno Ehrler Yana Vaynzof Richard H. Friend Artem A. Bakulin 《Liver Transplantation》2019,9(47)
Bulk heterojunction (BHJ) nonfullerene organic solar cells prepared from sequentially deposited donor and acceptor layers (sq‐BHJ) have recently been shown to be highly efficient, environmentally friendly, and compatible with large area and roll‐to‐roll fabrication. However, the related photophysics at donor‐acceptor interface and the vertical heterogeneity of donor‐acceptor distribution, critical for exciton dissociation and device performance, have been largely unexplored. Herein, steady‐state and time‐resolved optical and electrical techniques are employed to characterize the interfacial trap states. Correlating with the luminescent efficiency of interfacial states and its nonradiative recombination, interfacial trap states are characterized to be about 40% more populated in the sq‐BHJ devices than the as‐cast BHJ (c‐BHJ), which probably limits the device voltage output. Cross‐sectional energy‐dispersive X‐ray spectroscopy and ultraviolet photoemission spectroscopy depth profiling directly visualize the donor–acceptor vertical stratification with a precision of 1–2 nm. From the proposed “needle” model, the high exciton dissociation efficiency is rationalized. This study highlights the promise of sequential deposition to fabricate efficient solar cells, and points toward improving the voltage output and overall device performance via eliminating interfacial trap states. 相似文献
40.
Kan Shida Kotaro Takamizawa Masato Nagaoka Takao Tsuji Toshiaki Osawa 《Microbiology and immunology》1994,38(4):273-279
The binding of Escherichia coli heat-labile enterotoxin (LT) type I to glycosylated proteins with lactose (Galβ1-4Glc) by amino carbonyl reaction was studied by the Western blot assay and by the microtiter well binding assay. LT bound to a lactose-α-lactalbumin amino carbonyl product (Lac-LA), whereas cholera toxin did not. The binding ability of Lac-LA was abolished by β-galactosidase treatment, indicating that the terminal galactose is essential for the binding of LT. The binding of LT to Lac-LA was inhibited by galactose and lactose, and most effectively inhibited by lactulose (Galβ1-4Fru), which is a structural analog of the Amadori rearrangement product of the amino carbonyl reaction between lactose and an ε-amino group of a lysine residue (lactuloselysine). The results suggest that LT recognizes the portion of lactuloselysine in Lac-LA. LT also bound to a melibiose (Galα1-6Glc)-α-lactalbumin amino carbonyl product (Mel-LA), but the binding ability of Mel-LA was weaker than that of Lac-LA, suggesting that the β1-4 linked terminal galactose is dispensable but preferable for the binding. Furthermore, LT bound to the amino carbonyl products of lactose with β-lactoglobulin, caseins, bovine serum albumin, and ovalbumin. These results indicate that LT binds to the amino carbonyl products between proteins and sugars containing the terminal galactose, such as lactose. 相似文献