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991.
为考察保藏温度对厌氧氨氧化污泥颗粒特性的影响,同时优化保藏厌氧氨氧化颗粒污泥温度参数,本试验首先通过HRT调控进水基质负荷培养厌氧氨氧化颗粒污泥,并采用KHCO3和Na HCO3交替提供无机碳源。然后分别在–40℃、4℃、(27±4)℃室温和35℃条件下避光保藏。结果表明,Na HCO3可代替KHCO3作为厌氧氨氧化菌生长的无机碳源。相比于其他保藏温度,4℃保藏能够较好地维持生物量和生物活性,同时能较好地维持颗粒污泥的沉降性能、颗粒污泥和细胞结构完整性。在保藏过程中,一阶衰减指数模型可拟合厌氧氨氧化颗粒污泥生物量及活性的衰减过程,衰减指数与胞溶程度正相关,而且生物量的衰减比活性的衰减更快。同时,颗粒污泥胞外聚合物中蛋白质与多糖的比值(PN/PS)和血红素不能有效指示保藏过程中颗粒污泥沉降性能和活性的变化,而生物活性与胞溶程度呈负相关。 相似文献
992.
Elevated GAPDH expression is associated with the proliferation and invasion of lung and esophageal squamous cell carcinomas
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Lihong Hao Xin Zhou Shuqing Liu Mingzhong Sun Yang Song Sha Du Bing Sun Chunmei Guo Linlin Gong Jun Hu Shujuan Shao 《Proteomics》2015,15(17):3087-3100
Glyceraldehyde‐3‐phosphate dehydrogenase, is one of the most investigated housekeeping genes and widely used as an internal control in analysis of gene expression levels. The present study was designed to assess whether GAPDH is associated with cancer cell growth and progression and, therefore may not be a good internal control in cancer research. Our results from clinical tissue studies showed that the levels of GAPDH protein were significantly up‐regulated in lung squamous cell carcinoma tissues, compared with the adjacent normal lung tissues, and this was confirmed by western blotting and immunohistochemistry. GAPDH knockdown by siRNA resulted in significant reductions in proliferation, migration, and invasion of lung squamous carcinoma cells in vitro. In a nude mouse cancer xenograft model, GAPDH knockdown significantly inhibited the cell proliferation and migration/invasion in vivo. In summary, GAPDH may not be an appropriate internal control for gene expression studies, especially in cancer research. The role of GAPDH in cancer development and progression should be further examined in pre‐clinical and clinical studies. 相似文献
993.
994.
Structural analysis of the N- and C-termini in a peptide with consensus sequence. 总被引:1,自引:2,他引:1
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Y. Gong H. X. Zhou M. Guo N. R. Kallenbach 《Protein science : a publication of the Protein Society》1995,4(8):1446-1456
We present a structural analysis of a peptide, the sequence of which includes amino acids that show preferences for specific positions near the N- and C-termini in protein helices. This peptide has the sequence ac-YMSEDELKAAEAAFKRHGVP-amide, which includes a strong version of an N-terminal Harper-Rose capping box structure as well as a Gly located close to the C-terminus designed to elucidate its role in C-terminal capping. The sequence of five residues at the middle is inserted to separate effects at the two ends via a helix-stabilizing linker. Application of a simulated annealing procedure using interproton distance constraints derived from 1H NOESY experiments in water reveals the presence of a C-terminal structure in this model. The C-terminus forms a folded back structure in a significant fraction of structures generated by the annealing, in most of which Gly assumes an alpha L conformation. This structure occurs within a highly flexible region of the molecule and hence is occupied only a fraction of the time. 相似文献
995.
Traditional cultivation-based methods to quantify microbial abundance are not suitable for analyses of microbial communities
in environmental or medical samples, which consist mainly of uncultured microorganisms. Recently, different cultivation-independent
quantification approaches have been developed to overcome this problem. Some of these techniques use specific fluorescence
markers, for example ribosomal ribonucleic acid targeted oligonucleotide probes, to label the respective target organisms.
Subsequently, the detected cells are visualized by fluorescence microscopy and are quantified by direct visual cell counting
or by digital image analysis. This article provides an overview of these methods and some of their applications with emphasis
on (semi-)automated image analysis solutions. 相似文献
996.
Chong-Jun Yang Zhi-Xi Zhai Yu-Hai Guo Peng Gao 《植物学报(英文版)》2007,49(4):550-555
We investigated the role of the "sieve tube-companion cell complex" lining the tube periphery, particularly the microfilament and microtubule, in assisting the pushing of phloem sap flow. We made a simple phloem transport system with a living radish plant, in which the conducting channel was exposed for local treatment with chemicals that are effective in modulating protoplasmic movement (acetylcholine, (ACh) a neurotransmitter in animals and insects; cytochalasin B, (CB) a specific inhibitor of many cellular responses that are mediated by microfilament systems and amiprophos-methyl, (APM) a specific inhibitor of many cellular responses that are mediated by microtubule systems). Their effects on phloem transport were estimated by two experimental devices: (i) a comparison of changes in the amount of assimilates in terms of carbohydrates and ^14C-labeled photosynthetic production that is left in the leaf blade of treated plants; and (ii) distribution patterns of ^14C-labeled leaf assimilates in the phloem transport system. The results indicate that CB and APM markedly inhibited the transfer of photosynthetic product from leaf to root via the leaf vein, while ACh enhanced the transfer of photosynthetic product in low concentrations (5.0×10^-4 mol/L) but inhibited it in higher concentrations (2.0×10^-3 mol/L) from leaf to root via the leaf vein. Autoradiograph imaging clearly reveals that ACh treatment is more effective than the control, and both CB and APM treatments effectively inhibit the passage of radioactive assimilates. All of the results support the postulation that the peripheral protoplasm in the sieve tube serves not only as a passive semi-permeable membrane, but is also directly involved in phloem transport. 相似文献
997.
Dwarf bamboo species are monocarpic. They flower simultaneously and die after several decades. The type of flowering in the
genus Sasa ranges from sporadic to gregarious. In order to determine whether or not the sporadic flowering of dwarf bamboo is fixed
genetically, we investigated the distribution of clones using eight microsatellite (SSR) loci in a sporadic flowering patch
of Sasa cernua Makino, a major dwarf bamboo species found in central Hokkaido. In May 2006, flowering occurred on 60.5% of living culms
in a 1600 m2 patch. We established a 50 × 10 m study plot in this patch and noted 1267 clumps consisting of 2529 living culms. We investigated
all 1267 clumps and identified six multilocus genotypes as clones using five variable SSR loci. All flowering clumps belonged
to the same clone. On the other hand, non-flowering vegetative clumps were also discovered to be of the same clone. These
data suggest that all flowering culms originated from a single clone of a sporadic flowering patch of S. cernua. Clonal analysis for investigation of sporadic flowering of S. cernua revealed that only a portion of a clone flowers and dies instead of the whole clone. 相似文献
998.
Jurate Savickiene Grazina Treigyte Ceslava Aleksandraviciene Ruta Navakauskiene 《Central European Journal of Biology》2010,5(5):600-612
The biological effects of low-dose radiation have attracted attention, but data are currently insufficient to fully understand
the beneficial role of the phenomenon. In the present study, we have investigated the effects of low doses of gamma-irradiation
alone and in combination with all-trans-retinoic acid (RA) on proliferation, apoptosis and differentiation of the human promyelocytic leukemia HL-60 cells. Changes
in cell behavior and protein expression were determined with the use of light and fluorescent microscopy, immunocytochemical
and Western blot analysis. Low-dose irradiation with 1–100 cGy caused a dose-dependent inhibition of HL-60 cell proliferation,
and induced apoptosis and differentiation to granulocytes with an increase in the number of CD15-positive cells. Pre-irradiation
with 1–100 cGy for 24 h before treatment with RA promoted apoptosis but did not impair RA-induced differentiation. Both processes
were associated with a decrease in the expression of the proliferating cell nuclear antigen (PCNA), BCL-2, c-MYC, and changes
in both cytosolic and nuclear levels of protein tyrosine-phosphorylation as well as protein kinase C alpha or beta isoforms.
These results demonstrate the beneficial role of low-dose irradiation in modulating leukemia cell proliferation, differentiation
and apoptosis. 相似文献
999.
1000.
从31个60岁以上的符合中华医学会老年医学分会健康老年人标准的健康老人中随机选取4例作为研究对象,使用分子生物学方法,对他们的肠道双歧杆菌和乳杆菌种群多样性进行分析.研究结果表明,健康老人肠道中双歧杆菌的优势种群为长双歧杆菌(Bifi∥dobacterium longum)和假小链双歧杆菌(Bifidobacterium pseudocatenulatum),分别占双歧杆菌种群的55%和45%;而肠道乳杆菌则有唾液乳杆菌(Lactobacillus salivarius)50%、Lactobacillus mocosae 31.1%、口腔乳杆菌(Lactobacillus oris)6.3%、鼠李糖乳杆菌(Lactobacillus rhamnosus)6.3%和瑞士乳杆菌(Lactobacillus helveticus)6.3%,其中唾液乳杆菌、Lactobacillus mocosae为健康老人肠道优势乳杆菌种群. 相似文献