共查询到19条相似文献，搜索用时 250 毫秒
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植酸酶产生菌的筛选及产酶动态初探 总被引：1，自引：0，他引：1
用平皿培养法根据植酸钙溶解圈的有无从34种已知菌种中得到28株菌在0．1％植酸钙平板分离培养基上有明显的透明圈（占已知菌的82．4％），从中选黑曲霉，白地霉，毕赤酵母，酿酒酵母四株在0．1％植酸钙为唯一磷源的合成培养基中进行产酶动态分析，通过实验得到如下结论：[1]、许多微生物都能产生植酸酶．[2]、在0.1％植酸钙为磷源的合成培养基中，白地霉、黑曲霉均在培养6天酶活最高；酿酒酵母、毕赤酵母培养3天酶活最高；黑曲霉产酶最高，可达9．6IU／ml；毕赤酵母7．21U／ml；酿酒酵母6．0IU／ml；白地霉最低，酶活仅5．0IU／ml． 相似文献
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《陕西教育学院学报》2016,(12):145-148
本研究对西安地区特有葡萄品种——户太八号在自然发酵酿制葡萄酒的不同时期分离出的酵母菌种类进行研究。利用WL营养琼脂培养基,对分离出的339株酵母菌进行初步鉴定。结果表明,在发酵前期,分离出的酵母菌数量最少,种类最多,可归入6个属8个种,即葡萄汁有孢汉逊酵母、东方伊萨酵母、美极梅奇酵母、膜璞毕赤酵母、季也蒙有孢汉逊酵母、酿酒酵母、毕赤克鲁维酵母及红冬孢酵母,分别占发酵前期酵母菌总数的48.8%,20.9%,11.6%,7.0%,4.7%,2.3%,2.3%和2.3%;在发酵中期,分离出的酵母菌种类仅有4种,即酿酒酵母、东方伊萨酵母、毕赤克鲁维酵母及葡萄汁有孢汉逊酵母,分别占发酵中期酵母菌总数的67.1%,26.0%,5.5%和1.4%;而发酵末期,只有酿酒酵母。户太八号在自然发酵酿制葡萄酒的不同时期菌群种类不尽相同,为户太八号葡萄酒发酵过程中菌群种类动态变化的研究及优势菌种的筛选奠定了基础。 相似文献
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周咏梅 《中学数学教学参考》2011,(9):55-56
原题再现：（盐城卷第27题）
情境观察
将矩形ABCD纸片沿对角线AC剪开,得到AABC和△A’C’D,如图1（1）、图1（2）所示． 相似文献
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《河北自学考试》2003,(6)
(习题见上期)一、单项选择题1.D2.D3.D4.D5.C6.B7.B8.C9.D10.C11.D12.C13.C14.C15.D16.A17.C18.C19.A20.B21.A22.D23.A24.C25.C26.C27.A28.B29.A30.A二、多项选择题31.ABCDE32.CD33.BCE34.BCD35.ABCDE三、简答题36.表见代理是指行为人无代理权而以本人的名义与第三人为法律行为,但是有足以使第三人相信其有代理权的事实和理由的,该民事法律行为的后果由本人承担。构成表见代理应具备以下条件:(1)行为人没有代理权,却以本人的名义为民事行为。(2)客观上有足以使相对人信其有代理权的事实。(3)相对人主观上无过错。(4)行… 相似文献
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转化思想是在保证效果相同的前提下,将陌生、复杂的问题转换成熟悉、简单的问题。有些问题如果很难直接解答,那么,应该换一个方向、角度或一种观点来考虑,从新的方向、角度或观点出发,问题则可能变得更清晰、更明朗、易于解决。转化思想,它有着广泛的应用。本文从以下几方面来说明其应用。1透过过程抓本质,化繁琐为简单【例1】测得某个D N A分子中鸟嘌呤的含量为m,占整个分子的比值为b,若该D N A分子连续复制n次,则需原料A的量为。【常规方法】解:①求未复制前D N A中A的含量:A=(50-b)m/b。②采用数学归纳法求解(图1)。运用公式:s=ar(1… 相似文献
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《考试》2001,(11)
历史选择题答案:(共75分)一-一一一一一考武 1 .A 2.A 3.C 4.D 5.C 6.B 7.B 8.C 9 .A 10.C 11.C 12.C 13.B 14.C 15.D 16.A 17.D 18.A 19.D 20.B 21.A 22.A 23 .C 24 .B 25 .B 26 .B 27 .B 28 .B 29 .C 30 .C 二、材料解析题:(共34分) 31.答案要点(ro分) 答:①是为了加强边防的管理。涉及军事、政治、财经。削弱地方实力、加强中央集权。 ②指武将夺权与辽、夏相争。将内患当成主要矛盾。把外优看成次要矛盾。为其中央集权寻找根据,从而巩固其统治地位。 ③材料二以百年无惊为依据,持肯定的态度。材料四以虏骑所过为据,持否定… 相似文献
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1 .1 .A 2.1 3.D 4.C 5.E 6.G 7.F 8.B 9.J 10.H 11.1 1 .C 12.A 13.A 14.C 15.B 16.A 17.A 18.A 19.B 20.A 111.21.identify 22.dePression 23.suieide 24.Psychia妙25.interaet 26.feedbaek 27.Physieian 28.Preseribe 29.land 30尤叩he而stieally IV.31一35 F F T F F 36一 40 F T T FT V.41一45 A C A A D 46一50 D A D C B 51一55 A D A C B 56一60 B D A CD Vl.61一65 D A D A B 66一70 A C B AA Vll 71.Yes and the reasonsare:theMediterraneanhasnu比盯edmanyeivilizationsandthe‘limateisveryagreea… 相似文献
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Zhang Q Chen QH Fu ML Wang JL Zhang HB He GQ 《Journal of Zhejiang University. Science. B》2008,9(7):527-535
The bglS gene encoding endo-1,3-1,4-β-glucanase from Bacillus subtilis was cloned and sequenced in this study. The bglS expression cassette, including PGK1 promoter, bglS gene fused to the signal sequence of the yeast mating pheromone α-factor (MFals), and ADH1 terminator with G418-resistance as the selected marker, was constructed. Then one of the PEP4 allele of Saccharomyces cerevisiae WZ65 strain was replaced by bglS expression cassette using chromosomal integration of polymerase chain reaction (PCR)-mediated homologous recombination, and the bglS gene was expressed simultaneously. The recombinant strain S. cerevisiae (SC-βG) was preliminarily screened by the clearing hydrolysis zone formed after the barley β-glucan was hydrolyzed in the plate and no proteinase A (PrA) activity was measured in fermenting liquor. The results of PCR analysis ofgenome DNA showed that one of the PEP4 allele had been replaced and bglS gene had been inserted into the locus of PEP4 gene in recombinant strains. Different endo-1,3-1,4-β-glucanase assay methods showed that the recombinant strain SC-βG had high endo-1,3-1,4-β-glucanase expression level with the maximum of 69.3 U/(h-ml) after 60 h of incubation. Meanwhile, the Congo Red method was suitable for the determination of endo-1,3-1,4-β-glucanase activity during the actual brewing process. The current research implies that the constructed yeast strain could be utilized to improve the industrial brewing property of beer. 相似文献
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The aim of this paper is to use the microsatellites to evaluate acid-tolerance in Saccharomyces(S.) cerevisiae. Microsatellites have been widely used as the molecular marker to classify and identify S. cerevisiae strains, analyze genetic relationships among strains, and reveal genetic diversity of S. cerevisiae populations. In this paper, 25 key microsatellites of S. cerevisiae from 44 industrial yeast strains are investigated in the medium withconcentration gradients of acetic acid. Based on the analysis of correlations between the key microsatellite loci repeat numbers and acid-tolerance of the strains, the allele size of 4P14 a and 10P13 is positively related to acid-tolerance(p ? 0.05), the allele size of AT-X, 4P1 a and 10P8 are significantly negatively related to acid-tolerance(p ? 0.01). The above results provide informations on the molecular biodiversity of S. cerevisiae strains and can be a theoretical guidance for molecular marker assisted selection. 相似文献
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黄艳红 《宁德师专学报(自然科学版)》2010,22(1):11-14,25
将一种同时含C20-Δ5脂肪酸碳链延长酶（TFD5）基因和C22-Δ4脂肪酸碳链脱饱和酶（FAD4）基因的双基因共表达质粒转化于Saccharomyces cerevisiae中,形成了工程菌株SC.PYFTD5-FAD4.并对工程菌株SC.PYFTD5-FAD4进行了诱导表达,可直接转化底物二十碳五烯酸（EPA,20：5△5,8,11,14,17n-3）生成二十二碳五烯酸（DPA,22：5△4,7,10,13,16n-3）和二十二碳六烯酸（DHA,22：6△4,7,10,13,16,19n-3）. 相似文献
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Both salient visual events and scene-based memories can influence attention, but it is unclear how they interact in children and adults. In Experiment 1, children (N = 27; ages 7–12) were faster to discriminate targets when they appeared at the same versus different location as they had previously learned or as a salient visual event. In contrast, adults (N = 30; ages 18–31) responded faster only when cued by visual events. While Experiment 2 confirmed that adults (N = 27) can use memories to orient attention, Experiment 3 showed that, even in the absence of visual events, the effects of memories on attention were larger in children (N = 27) versus adults (N = 28). These findings suggest that memories may be a robust source of influence on children's attention. 相似文献
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Purpose: To investigate the relationship between expression of cell cycle-related protein cyclin D1, p27kipl and the pathogenesis of bronchioloalveolar carcinoma (BAC) and the value of prediction of prognosis. Methods: Cyclin D 1 and p27kip 1 protein were detected by immunohistochemical En Vision method in 43 BACs. Results: The positivity of cyclin D 1 in BAC was 65.1% (28/43), which was significantly higher than that in normal pulmonary tissue (0/13), P＜0.01. No statistically significant association was found between cyclin D1 expression data and sex, age, tobacco-use history, histologic subtype (mucinous vs nonmucinous), stromal fibrosis, lymph node metastasis, clinical stage or postoperative survival period (P＞0.05), while cyclin D1 expression was found to be negatively correlated with tumor size (P＜0.05). The positivity of p27kipl in BACs was 51.2% (22/43), significantly lower than that in normal pulmonary tissue (12/13), P＜0.01. p27kipl expression level was not associated with sex, age, tobacco-use history, tumor size or histologic subtype (P＞0.05), but was negatively correlated with stromal fibrosis, lymph node metastasis and clinical stage (P＜0.05); and positively associated with postoperative survival period (P＜0.01). The survival rate of p27kipl positive group was significantly higher than that of p27kipl negative group (P＜0.01). No statistically significant correlation was found between cyclin D 1 and p27kipl expression. Conclusions: Increased cyclin D1 expression and decreased p27kip 1 expression are related to the pathogenesis of BAC;decreased p27kipl expression is associated with metastasis progression; immunodetection ofp27kip 1 is useful for assessment of prognosis. 相似文献
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A menaquinone-7 (MK-7) high-producing strain needs to be isolated to increase MK-7 production, in order to meet a requirement of MK-7 given the low MK-7 content in food products. This article focuses on developing MK-7 high-producing strains via screening and mutagenesis by an atmospheric and room temperature plasma (ARTP) mutation breeding system. We isolated an MK-7-producing strain Y-2 and identified it as Bacillus amyloliquefaciens, which produced (7.1±0.5) mg/L of MK-7 with maize meal hydrolysate as carbon source. Then, an MK-7 highproducing strain B. amyloliquefaciens H.β.D.R.-5 with resistance to 1-hydroxy-2-naphthoic acid, β-2-thienylalanine, and diphenylamine was obtained from the mutation of the strain Y-2 using an ARTP mutation breeding system. Using strain H.β.D.R.-5, efficient production of MK-7 was achieved ((30.2±2.7) mg/L). In addition, the effects of nitrogen sources, prenyl alcohols, and MgSO4 on MK-7 production were investigated, suggesting that soymeal extract combined with yeast extract, isopentenol, and MgSO4 was beneficial. Under the optimized condition, the MK-7 production and biomass-specific yield reached (61.3±5.2) mg/L and 2.59 mg/L per OD600 unit respectively in a 7-L fermenter. These results demonstrated that strain H.β.D.R.-5 has the capacity to produce MK-7 from maize meal hydrolysate, which could reduce the substrate cost. 相似文献
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Lung Hung Chen Chia-Huei Wu Ying Hwa Kee Meng-Shyan Lin Shang-Hsueh Shui 《Contemporary educational psychology》2009,34(4):298-305
In this study, the hierarchical model of achievement motivation [Elliot, A. J. (1997). Integrating the “classic” and “contemporary” approaches to achievement motivation: A hierarchical model of approach and avoidance achievement motivation. In P. Pintrich & M. Maehr (Eds.), Advances in motivation and achievement (Vol. 10, pp. 143–179). Greenwich, CT: JAI Press] is used to investigate the motivational mechanism behind the relationship between fear of failure and self-handicapping adoption. A cross-sectional design was employed. The participants were 691 college students enrolled in physical education in Taiwan. Students completed the Performance Failure Appraisal Inventory (PEAI-S; Conroy, D. E., Willow, J. P., & Metzler, J. N. (2002). Multidimensional measurement of fear of failure: The performance failure appraisal inventory. Journal of Applied Sport Psychology, 14, 76–90), the Chinese 2 × 2 Achievement Goal Questionnaire for Physical Education (CAGQ-PE; Chen, L. H. (2007). Construct validity of Chinese 2 × 2 achievement goal questionnaire in physical education: Evidence from collectivistic culture. Paper presented at the 5th conference of the Asian South Pacific Association of Sport Psychology. Bangkok, Thailand) and the Self-Handicapping Scale (SHS; Wu, C. H., Wang, C. H., & Lin, Y. C. (2004). The exploratory and confirmatory factor analysis of self-handicap scale for sport. Journal of Higher Education in Physical Education, 6(1), 139–148). Structural equation modeling was conducted. Generally, the results showed that mastery-avoidance and performance-avoidance goals partially mediated the relationship between fear of failure and self-handicapping. The results are discussed in terms of the hierarchical model of achievement motivation, and its implications for physical education are also highlighted. 相似文献
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一个来自细菌转座子Tn5中的博莱霉素抗性基因能够赋予细菌对平阳霉素的抗性;平阳霉素对E.coli和一些真核生物(酵母、植物)生长的最低抑制浓度. 相似文献