Energy conservation during nitrate respiration in Paracoccus denitrificans

P/2e ratios were calculated from anaerobic chemostat cultures of Paracoccus denitrificans with nitrogenous oxides as electron acceptor. P/2e ratios were calculated, using the Y _ATP ^max values determined for aerobic cultures. When succinate was the carbon and energy source the average P/2e values of the sulphate-and succinate-limited cultures with nitrate as electron acceptor were 0.5 and 0.7, respectively, and of the nitrite-limited culture 0.9. With gluconate as carbon and energy source the average P/2e values of the gluconate-limited with nitrate as electron acceptor and nitrate limited cultures were 0.9 and 1.1, respectively.H⁺/O ratios measured in cells obtained from sulphate-, succinate, nitrite-, gluconate-and nitratelimited cultures yielded respective average values of 3.4, 4.5, 3.5, 4.8 and 6.2 for endogenous substrates. From our data we conclude that sulphate-and nitritelimitation causes the loss of site I phosphorylation. Nitrite has no influence on the maximum growth yield on ATP. We propose that metabolism in heterotrophically grown cells of Paracoccus dentrificans is regulated on the level of phosphorylation in the site I region of the electron transport chain.     

Energy requirements for growth and maintenance of Scenedesmus protuberans Fritsch in light-limited continuous cultures

Scenedesmus protuberans Fritsch was grown in light-limited continuous cultures with a light-dark cycle, at temperatures of 20° and 28° C. At 20° irradiances of 12 and 38 W m^–2 were used, at 28° 38 W m^–2.The relationships between growth rate and light uptake rate were of diphasic linear character. With the lower growth rates the relationships were defined with the parameters _e , i.e. the specific maintenance rate constant, and c, the true efficiency of light energy conversion into biomass. The _e -value was dependent on temperature, the c on irradiance.In cultures, incubated in prolonged darkness, decrease rates of biomass were comparable to the derived _e -values.Both diphasic linear relationships between growth rate and light uptake rate and the same order of magnitude of _e -values could be derived from literature data on other green algae.     

糖尿病肾病与非糖尿病肾病维持性血液透析患者血钙、血磷及甲状旁腺激素水平的分析

目的：探讨糖尿病肾病（diabtic nephropgthy,DN）与非糖尿病肾病（non-DN）维持性血液透析患者（maintenance hemodialysis,MHD）血钙、血磷、甲状旁腺激素（intact parathyroid hormone,iPTH）水平的差异;分析其血钙、血磷、iPTH和糖化血红蛋白（glycosylated hemoglobin,HbA1c）水平的相关性。方法：选择沈阳军区总医院血液透析中心收治的148例MHD患者,分为糖尿病组（58例）和非糖尿病组（90例）,比较两组间血钙、血磷、甲状旁腺激素水平的差异,并分析其血钙、血磷、iPTH、HbA1c水平的相关性。结果：糖尿病组iPTH、血磷水平均明显低于非糖尿病组（P〈0.05）,两组血钙水平比较无明显差异。在非DN组中,iPTH与血钙水平呈显著负相关（r=-0.320,P=0.036）,iPTH与血磷水平呈明显正相关（r=0.426,P=0.005）。在DN组中,iPTH与血钙、血磷无显著相关性,而iPTH与HbA1C水平呈显著负相关（r=-0.732,P=0.007）。结论：糖尿病肾病血液透析患者的iPTH水平和血磷水平明显低于非糖尿病肾病血液透析患者,HbA1c可能抑制iPTH的分泌。     

医院医疗器械维修中存在的问题及维修管理对策研究

近几年来,随着科学技术的发展和医院规模的扩大,社会对医疗技术要求不断提高,因此,高端医疗器械和新型医疗设备需求加大,医疗器械管理与维修也需跟进。医疗器械的正常使用在医疗工作中有着举足轻重的作用,可提高医疗人员的工作效率,提升临床诊治的水平,但其在改善医疗条件的同时也存在一系列的问题,若无法保质和及时维修医疗器械,对正常医疗设备的使用具有严重影响,延误患者的就诊与治疗。目前医院医疗器械维修中存在的维修人员整体素质偏低、管理机制不健全、维修技术落后、医疗器械维修人员不足、缺乏积极性及再学习的机会、医疗器械缺乏定期保养和管理等实际问题,导致医疗器械维修效率低,本文就以上问题展开讨论,旨在为医院维修管理的制定提供参考。     

Photosynthesis and respiration in Alocasia macrorrhiza following transfers to high and low light

Summary Photosynthetic capacities and respiration rates of Alocasia macrorrhiza leaves were measured for 4 weeks following reciprocal transfers between high (20% of full sun) and low (1% of full sun) light environments. Photosynthetic capacities and respiration rates of mature, high-light leaves were 1.7 and 4.5 times those of low-light leaves, respectively. Following transfer, respiration rates adjusted within 1 week to those characteristic of plants grown in the new environment. By contrast, photosynthetic capacities either did not adjust or changed only slowly following transfer. Most of the difference in respiration between high- and low-light leaves was related to the carbohydrate status as determined by the daily PFD and little was directly related to the maintenance costs of the photosynthetic apparatus. Leaf construction cost was directly proportional to maximum photosynthetic capacity. Consequently, although daily carbon gain per unit leaf area was the same for low-light and high to low-light transferred plants within a week after transfer, the carbon return per unit of carbon investment in the leaves remained lower in the high to low transfer plants throughout the 4 week measurement period. Conversely, in high-light, the low leaf construction cost of the low to high-light transferred plants resulted in carbon gain per unit investment just as high as that of the high-light plants.     

调理脾胃法治疗维持性血透患者营养不良的报告

目的:探讨调理脾胃法治疗维持性血透患者营养不良的效果.方法:40例维持性血透患者随机分为治疗组和对照组,两组在对症处理相同、血透相关因素一致条件下进行维持血透治疗,治疗组同时根据辨证分型服用调理脾胃中药,疗程3个月.结果:与本组治疗前相比较,治疗后的各项生化指标明显提高(P<0.01),蛋白分解率也较治疗前提高(P<0.05),SGA分级好转(P<0.01),临床常见症状体征积分随治疗时间延长呈下降趋势(P(0.05);治疗组与对照组治疗后的各项生化指标、蛋白分解率、SGA分级及临床常见症状体征积分等差异均具有显著性(P<0.05).结论:中药调理脾胃法可以改善维持性血透患者营养不良状况.     

The complete nucleotide sequence of the colicinogenic plasmid ColA. High extent of homology with ColE1

Summary The complete nucleotide sequence of the colicinogenic plasmid ColA has been determined. The plasmid DNA consists of 6720 bp (molecular weight 4.48×10⁶). Fifteen putative biological functions have been identified using the functional map previously determined. These include 11 genes and 3 DNA sites. Nine genes encode proteins of which 3 have been fully characterized. The replication region of ColA coding for RNAI and RNAII is highly homologous to that of ColE1 andClo DF13. The same holds true for the site-specific recombination region containing palindromic symmetry and involved in stable maintenance of the plasmids. A high percentage of homology has been detected for putative mobility proteins encoded by ColA and ColE1. The exclusion proteins are also highly homologous.     

二态混合交配系统的适合度优势及其维持机制研究进展

由开花受精花(chasmogamous, CH)和闭花受精花(cleistogamous, CL)构成的二态混合交配系统植物有着特殊的繁殖策略, 对其进行深入研究有助于理解植物交配系统的维持机制、进化趋势以及植物对环境变化的应对策略。本文综述了国内外关于CH-CL系统两型花研究的文献资料, 包括非生物因素和生物因素对该繁育系统两型花的生长、发育及相对比例的影响, 两型花的维持机制及进化意义, 阐明了CH-CL系统的研究现状及科学问题, 重点评述了基于近年来对CH-CL系统研究成果的新认识。作者提出, 精确地检测两种花型的后代在异质生境下以及在生活史的不同阶段的适合度差异是十分必要的; 微环境(种子的散布模式及位置效应)对两型花种子萌发和子代生长发育的影响非常重要; 两型花表达的时空差异(即开花模式及对异质生境的敏感性差异)的表达机制可能与内源激素的水平变化相关; 对于多年生具CL系统植物来说, 不同性质、不同来源的后代在居群中的分布式样及对居群遗传结构的影响很可能是该系统维持的重要机制。因此, 深入研究和科学认识二态混合交配系统对认识整个植物界繁育系统的进化有十分重要的意义。     

23个实验小鼠和大鼠近交系的保种研究

从1985年开始,陆续从国外实验动物著名机构引进常用近交系小鼠共23个品系(亚系和亚群)。在多年来保种繁殖过程中,根据修饰平行线系统选择留种动物,同时对动物进行全兄妹近亲交配繁殖,保持完整的谱系记录,控制饲养环境条件,成功地保持了绝大多数品系。同时对多数品系的繁殖性能和体重增长进行了观察,为这些品系的实验应用提供基本参数。     

From individual interactions to population dynamics: individual resource partitioning simulation exposes the causes of nonlinear intra-specific competition

Intra-specific competition defines the relationship between population density and the performance of individual organisms (R-function). Observation of this relationship in nature shows it to be frequently nonlinear, and it has been argued, on intuitive grounds, that this nonlinearity is due to the type of competition (scramble or contest) being expressed. Here, we use an individual-based simulation model to investigate the effects of three resource partitioning schemes, representing different types of competition, on the form of the R-function. Results indicate that all resource partitioning schemes can give rise to concave or convex functions depending on the balance between maximum individual birth rate, maintenance cost, and demand for resources. Given high growth rates and maintenance costs, contest competitors tend to exhibit less concavity than scramblers. Therefore, population stability can be strongly affected by the strategy of resource partitioning. Life histories and environmental conditions that encourage the homogeneous distribution of resources among individuals lead to complex and unstable dynamics. Stable dynamics is fostered by heterogeneous resource distribution, which could result from such things as social hierarchies, individual and environmental variability, and large, indivisible resource packets.