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1.
利用黑麦培养基和V8-蔬菜汁培养基研究了马铃薯晚疫病菌Phytophthora infestans特异菌株DK98-1、DX98-2和DX98-3的生物学特性,发现该菌株与普通菌株相比菌落生长速度慢、孢子囊产生数量少、有性杂交后卵孢子产生量大(2047~75623个/cm2);利用AFLP分子标记研究这3个菌株的DNA指纹图谱,发现用引物E CG/M CC扩增菌株DK98-1、DX98-2和DX98-3后,在330bp处与普通菌株相比各缺失一条谱带,用引物E AC/M CT扩增菌株DK98-1、DX98-2和DX98-3后,在370bp处比普通菌株增加1条谱带,说明这3个菌株与普通菌株在遗传上明显不同。同时可以利用上述2对特异性引物,鉴定在自然界的晚疫病菌群体中这类特异菌株的出现频率。 相似文献
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Progesterone, but not the synthetic progestagen R-5020, was as good as aldosterone in displacing the mineralocorticoid from its specific receptor in rat kidney both in classical competition studies and in aldosterone binding to MR1 and MR2 components of MR during physical separation. Paradoxically, at equimolar (10?8 M) concentrations, both gestagens (progesterone = 1, R-5020 = 20) were preferentially bound to the MR4 component which coeluted with serum bound 14C-corticosterone (or 14C-progesterone), which could not be labelled with aldosterone in the kidney, and which could not be detected in the liver and the serum under any condition. The MR1 entity, at 10?8 M, was saturated as: aldosterone = 2, R-5020 = 1 = progesterone. Thus, the agonist and the antagonist function in mineralocorticoid action may be expressed by two or more distinct and different sites. 相似文献
3.
Three specific growth rates, 0.23, 0.45 and 0.51 h–1, were used to cultivate Corynebacterium glutamicum in a pH-auxostat. The specific formation rates of most amino acids increased by raising the specific growth rates. The highest specific growth rate, 0.51 h–1, favors the production of LEU; whereas the highest production yield for ALA and GLU were at = 0.23 h–1. A correlation among specific growth rates, glucose consumption rate, and production yields of amino acids was obtained. 相似文献
4.
目的:生物法合成1,3-丙二醇时,pH值对于产物谱有着显著影响。本文将研究不同pH值对克雷伯氏肺炎杆菌(Klebsiella pneumoniae)的中心碳代谢的影响。方法:设计单因素试验,控制发酵pH值,用5L Braun发酵罐进行批次发酵,分析发酵过程中产物时序性合成的特性。结果:pH 6.2到7.4适合菌体生长;不同pH值对于葡萄糖消耗无明显差异;pH6.8时能在较长时间保持在高水平的甘油比消耗速率;在偏碱性条件下,有机酸丁二酸、乳酸、乙酸的比生长速率显著增大;而2,3-丁二醇在偏碱性的pH7.4和8.0时根本不能合成。pH6.8时1,3-丙二醇的得率最大,不同pH条件下碳回收率相当。结论:证明了pH值对K. pneumoniae中心碳代谢具有显著影响,不同产物呈现不同的合成动力学特性,其详细机理有带进一步深入研究。 相似文献
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Circadian periodicity in cell division and death was investigated in the cyanobacterium Anabaena flos-aquae (Lyngb.) Bréb in a phosphorus (P)-limited, N2 -fixing chemostat culture. When entrained under 12:12 h LD cycles, not only cell division but also cell death showed a clear circadian rhythm in this filamentous cyanobacterium. The rhythm persisted under continuous light and was temperature compensated. Circadian rhythm was clearly observed in the steady-state cell number and instantaneous growth rate, μ(t), which reached a maximum at about 2 h before sunset and a minimum at about 2 h before sunrise. The number of dead cells and the instantaneous death rate γ(t) also showed a circadian periodicity; the peak of γ(t) occurred approximately 8 h before that of μ(t). Therefore, cell growth and death in A. flos-aquae appear to be under the control of circadian clocks, and thus it seems that their death is programmed cell death. 相似文献
6.
Tissue specific methylation of human Y chromosomal DNA sequences 总被引:1,自引:0,他引:1
Yutaka Nishioka 《Tissue & cell》1988,20(6):875-880
This report describes two moderately repetitive human Y chromosomal DNA sequences isolated from a flow sorted Y chromosonal library. These sequences are present in XY male and XY female DNAs but absent in XX male and XX female DNAs. Genomic Southern blot analysis against DNAs isolated from different tissues showed tissue specific DNA methylation patterns. In contrast to the 2.1 kb Hae III repeats which are hypomethylated in sperm DNA, the moderately repetitive sequences used in this study are highly methylated in sperm, less methylated in blood and brain and least methylated in placental DNA. 相似文献
7.
This study reports hematocrit and blood chemistry values for captive adult individuals belonging to three genera of hornbills (Bucerotidae), Aceros, Anthracoceros, and Ceratogymna, and evaluates genera and gender specific differences in these values. Ceratogymna differs significantly from the other two genera in the concentration of total proteins, cholesterol, triglycerides, phosphorus, potassium, and sodium. Blood glucose concentrations in Aceros were lower than those in the other two genera. Plasma levels of enzymes differed between Aceros and Ceratogymna. With respect to gender differences, Aceros males had greater plasma levels of alanine aminotransferase (ALT), calcium and phosphorus than did the females, and the Ceratogymna males had higher concentrations of triglycerides. Body mass was correlated with hematocrit, cholesterol, total proteins, and urea in Aceros and with calcium concentration in Ceratogymna. These results are the first data available on reference ranges of blood values in individuals of this family of birds and may therefore be very useful as a complementary diagnostic tool in the veterinary care of individuals of these species in captivity. Zoo Biol 0:1–9, 2005. © 2005 Wiley‐Liss, Inc. 相似文献
8.
簇毛麦基因组特异性PCR标记的建立和应用 总被引:10,自引:0,他引:10
以普通小麦中国春、簇毛麦、中国春-簇毛麦二体附加系和代换系为材料进行RAPD分析,筛选出一个簇毛麦基因组特异性RAPD片段OPFO2757,该片段分布于簇毛麦所有染色体上。在对OPFO2757进行克隆、测序的基础上,设计一对PCR引物,建立了簇毛麦基因组特异性PCR标记。用这对PCR引物对不同普通小麦品种、不同硬粒小麦品种、不同居群的簇毛麦、中国春-簇毛麦二体附加系、中国春-簇毛麦二体代换系、普通小麦-簇毛麦双二倍体、硬粒小麦-簇毛麦双二倍体等材料进行扩增,凡具有簇毛麦染色体的材料都能扩增出一条长为677bp的DNA片段,而不具簇毛麦染色体的材料包括大麦、黑麦、长穗偃麦草、中间偃麦草等不能扩增出该片段。所以,该特异性PCR标记可用于快速跟踪检测小麦背景中的簇毛麦染色体。 相似文献
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N. H. Thuy L. A. Tien P. N. Tuyet D. T. T. Huong N. V. Cong M. Bayley T. Wang S. Lefevre 《Journal of fish biology》2010,76(4):1025-1031
Oxygen uptake () and critical oxygen tension (Pcrit) were measured in resting perch Perca fluviatilis that were either fasting or digesting. Digestion caused to double (from 61 to 117 mg O2 kg?1h?1) and was associated with a rise in Pcrit (from 3·4 to 4·9 kPa), showing that the animal's digestive state must be considered when assessing the effect of hypoxia in natural conditions, and when defining optimal oxygen conditions in aquaculture. 相似文献
11.
真菌是生物多样性最丰富和生存环境最多样的生物类群之一,除了我们熟知的土壤、植物残体、水体等一般环境外,还存在极地、高温、高盐等各种特殊环境.对真菌而言,特殊环境是指绝大多数真菌不能生存的环境,而特殊环境真菌是指特殊环境中特有的真菌或适应特殊环境的真菌.特殊环境人为地划分为以下3种类型:第一类,具有某种特定的理化限制因素的环境;第二类,某些特殊基质;第三类,受多因素限制的特殊复杂环境.特殊环境真菌有着独特的适应性,并进化出各种机制来占据生态位.它们在细胞构造、代谢方式、进化机制等方面的特殊性引起了科学家的广泛关注.本文介绍了各种特殊生态环境下生活的真菌类群以及它们的生存机制,并对今后的研究方向进行了展望. 相似文献
12.
目的:评估前列腺特异抗原密度(prostate specific antigen density,PASD)对前列腺癌根治术后不良病理结果的预测价值.方法:回顾性分析50例病理确诊为前列腺癌患者的临床资料,收集患者术前总前列腺特异抗原(total prostate specific antigen,tPSA)、PSAD及穿刺活检Gleason评分结果,比较在手术切缘阳性(positive surgical margins,PSM)、前列腺包膜外侵犯(extracapsular prostatic extension,EPE)、精囊入侵(seminal vesicle invasion,SVI)患者中以上各项指标的差异,对有统计学差异的因素行多元Logistic回归分析,筛选影响浸润的最主要因素,同时运用工作特征曲线(ROC曲线)比较各指标的预测价值.结果:PSM,EPE和SVI患者之间PSAD存在统计学差异,PSAD曲线下面积高于PSA与Gleason评分.多元Logistic回归分析结果表明,PSAD和Gleason评分对PSM和EPE有着统计学意义的预测价值,且PSAD和PSA与SVI有关.结论:PSAD可作为接受前列腺癌根治术的患者术后不良的预测指标. 相似文献
13.
The apparent specific volumes of human deoxy-, oxy-, met-, and CN-met hemoglobin (Hb) were measured with a vibrating tube densitometer. The values were calculated from the difference in density between protein solutions and solvents with which they were in dialysis equilibrium. The results obtained were very similar to the value for horse HbCO often used for sedimentation studies of Hbs. The apparent specific volumes of oxy- and CN-metHb are approximately 0.0020 cm(3)/g higher than those of deoxy- and metHb. This small reproducible difference could be due either to a small conformational difference between the liganded and unliganded species or to different interactions with components of the solvent. On the basis of these results, a simple method for the determination of the contribution of the heme to the apparent specific volume is proposed. The contribution can be estimated from the difference between the measured volume of each molecular species and that calculated from the amino acid composition. 相似文献
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The 1st step initiation essential for allergen‐specific IgE antibody production upon the 2nd step: Induction of non‐specific IgE+ small B cells containing secondly‐sensitized allergen‐specific ones in mice firstly‐sensitized with an allergen
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Natsuki Hannya Hiromi Ogita‐Nakanishi Ryuji Kato Yoshio Ijiri Tetsuya Hayashi Kazuhiko Tanaka Ryo Kawata Hiroshi Takenaka Takahiro Kubota Ryotaro Yoshida 《Microbiology and immunology》2018,62(2):99-110
15.
三红妇康精对大鼠免疫功能的影响 总被引:2,自引:0,他引:2
三红妇康精按7.5g/kg剂量给大鼠灌喂,每天1次,连续10天,可明显提高大鼠外周血酸性α-醋酸萘酯酶阳性淋巴细胞的百分率和大鼠脾特异性玫瑰花环形成细胞的比率,但对大鼠外周血中性白细胞吞噬率无明显影响。提示三红妇康精有提高机体细胞免疫和体液免疫功能的作用。 相似文献
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植物的叶片与细根分别作为植物体地上和地下部分重要的营养器官, 很多功能性状在二者之间存在着一定的关联性。研究这种关联有助于理解植物各性状之间的相互作用、植物生长过程中对资源的利用和分配, 以及建立细根性状的估算模型。该研究对内蒙古锡林河流域65种植物叶片与细根的氮(N)含量、磷(P)含量、N:P以及比叶面积(SLA)和比根长(SRL)进行了比较研究, 结果表明: 在种间尺度上, 叶片与细根间的N、P和N:P存在显著的相关性, 而SLA与SRL之间相关性较弱; 在种内尺度上, 叶片和细根的N、P及SLA与SRL, 在不同的物种中呈现出不同的趋势。此外, 叶片与细根性状的关联, 在不同的植物功能群之间存在差异。例如, 双子叶植物叶片与细根间的N含量显著相关, P含量不相关; 而单子叶植物二者之间的P含量显著相关, N含量无关联。该研究的主要结论是, 在相对一致的生境中, 植物叶片与细根性状的关联主要发生在不同物种之间, 在种内尺度上这种关联不明显, 这可能与植物功能性状在种内存在较小的变异幅度有关。 相似文献
18.
Variation in plant functional traits across and within four species of Western Australian Banksia (Proteaceae) along a natural climate gradient
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Anne Cochrane Gemma L. Hoyle Colin J. Yates Teresa Neeman Adrienne B. Nicotra 《Austral ecology》2016,41(8):886-896
Plant traits are fundamental components of the ecological strategies of plants, relating to how plants acquire and use resources. Their study provides insight into the dynamics of species geographical ranges in changing environments. Here, we assessed the variation in trait values at contrasting points along an environmental gradient to provide insight into the flexibility of species response to environmental heterogeneity. Firstly, we identified how commonly measured functional traits of four congeneric species (Banksia baxteri, B. coccinea, B. media and B. quercifolia) varied along a longitudinal gradient in the South Western Australian Floristic Region. This regional gradient provides significant variation in moisture, temperature and soil nutrients: soil nitrogen content decreases with declining rainfall and increasing temperature. We hypothesized that (i) the regional pattern in trait–environment associations across the species would match those observed on a global scale and (ii) that the direction and slopes of the within‐species relationships would be similar to those across species for each of the measured traits. Along the regional gradient we observed strong shifts in trait values, and cross‐species relationships followed the expected trend: specific leaf area was significantly lower, and leaf Narea and seed dry mass significantly higher, at the drier end of the rainfall gradient. However, traits within species were generally not well correlated with habitat factors: we found weak patterns among populations, either due to the small ecological gradient or perhaps because fine‐scale structuring among populations (at a micro‐evolutionary scale) was low due to high gene flow within species. Understanding how species traits shift as a result of climatic influences, both at the regional (across species) and local (within species) scale, provides insight into plant adaptation to the environment. Such studies have important applications for conservation biology and population management in the face of global change. 相似文献
19.
Wang X Yin L Rao P Stein R Harsch KM Lee Z Heston WD 《Journal of cellular biochemistry》2007,102(3):571-579
Over a half century ago, Charles Huggins demonstrated the response of prostate cancer to androgen deprivation therapy. Subsequently, many discoveries and evolving findings continued to support a research rationale focused on the androgen receptor (AR) as a key target for prostate cancer. More recently, preliminary trials have suggested that other targets could also be useful in the treatment of prostate cancer, and the proposed strategies for treatment have ranged from targeted toxins to immunotherapeutic agents. We provide an overview of some of these approaches, with an emphasis on those that employ prostate specific membrane antigen (PSMA) as a target. 相似文献
20.
小鼠鼻咽部组织相对特异基因调控区的克隆与分析 总被引:2,自引:0,他引:2
张玲 李虹 谢鹭 蓝轲 韩为农 冯湘玲 何志巍 姚开泰ZHANG Ling LI Hong LAN Ke HAN Wei-nong FENG Xiang-ling HE Zhi-wei YAO Kai-tai 《遗传》2001,23(3):203-206