微生态学研究的重要意义和实际应用

人类正面临着内、外两大环境的挑战 ,外环境属于宏观生态学的研究领域 ,而内环境属于微生态研究领域。随着人类文明的发展 ,人们越来越重视宏观生态对人类生存的影响 ,因此有人说保护生态就是保卫地球即保护人类自身的发展和文明 ;相反破坏生态 ,就一定会招致大自然对人类的惩罚。比如说 ,我国早期发展对生态环境保护重视不够 ,如砍伐森林 ,围海 (湖 )造田 ,破坏植被 (草原 ) ,造成江河枯褐、改道或洪水泛滥或沙暴肆虐 ,这些都是大自然对人们破坏生态的惩罚 ,这些教训人们还历历在目。另一方面 ,对微生态 (微观环境 )研究领域认识还远远不够…     

微生态学在医学领域中的应用

20世纪 5 0年代初期 ,我国著名微生态学家、微生态学先驱者魏曦教授、刘秉阳教授创建了我国的微生态新学科 ,并后继由康白教授发扬光大 ,使我国微生态学蓬勃发展。人体微生态的许多基本规律都是从胃肠道微生态学研究得出的。胃肠道微生态的研究与现代医学许多基础学科和临床学科有广泛的联系 ,胃肠道正常菌群参与了人体的生理、生化、病理和药理过程。肠道的解剖结构与肠道的正常微生物群的存在有着密切的关系。正常菌群实际上已成为宿主生命的必须的组成部分。微生态学的研究对象主要是有生命的宿主。对一定解剖部位的疾病生理、病理解剖、…     

RAPD技术及其在哺乳动物生态学研究中的应用

1　引　言现代生态学的不断发展 ,改变了过去主要采用宏观的方法来研究生物与生物及环境的关系。在种群生态学研究中 ,越来越多的学者采用微观的分子生物学技术来研究种群的生存问题 ,新学科分子生态学得到快速的发展。目前 ,从分子水平来研究种群生态 ,较多采用限制性酶切图谱 (ＲＦＬＰ)和以ＰＣＲ为基础的ＲＡＰＤ技术以及ＤＮＡ序列分析技术。在使用这些技术时 ,很多实验的条件往往会影响实验的结果。本文根据作者在实验中的体会 ,结合一些研究者已有的工作 ,对ＲＡＰＤ的原理、影响因素以及在哺乳动物生态学研究中的应用作简单介绍。2 …     

分子遗传学在消化道微生态学研究中的应用

近20年来,消化道微生态学得到了迅速的发展,主要成就有:(1)实验技术的发展,如悉生动物的普及,厌氧培养技术的完善、肠道微生物代谢产物分析技术的建立等;(2)对人和动物消化道生态系统及正常菌群的特征与作用有了进一步的了解;(3)研究成果迅速应用于实践,如在新生儿中接种无质粒非致病大肠杆菌以防止致病性大肠杆菌的肠道定植,各种益生素(Probiotics)在人或畜牧业中的应用。我国学者也做了大量工作,并取得了相当成果(详见各期《中国微生态学杂志》)。     

微生态学在现代医学中的定位

人体 ,或更正确地说生物体 ,其生命的存在必须与其内、外环境相适应。不适应 ,只能是患病或死亡。生命与环境是对立的统一体。没有生命无所谓环境 ,没有环境无所谓生命。一切生物体都有其适应环境的极限 ,超过极限就必然失去生命。人类是智慧动物 ,能够扩大其适应环境的极限 ,但不可能没有极限。没有极限就违背了“生命与环境对立的统一”客观规律。因此人体或生物体必须与环境相适应。人体或生物体对外必须适应大环境 ,亦即必须适应地球上的水、土壤及大气结构与变化的客观环境。这就是宏观生态学 (m acroecology)研究的领域。在另一方面 ,…     

微生态学在发达国家及中国的历史和现状

微生态学在发达国家及中国的历史和现状大连医科大学微生态学研究所康白微生态学,作为一门生命科学分支,首先是由前东德中央营养研究所Ｈａｅｎａｌ与Ｌｏｈｍａｎｎ于１９６４年提出来的。他们于１９６４年在柏林组织了第一届国际微生态学讨论会（ＨａｅｍｅｌａｎｄＬ...     

溃疡性结肠炎的微生态学研究与防治

目的 :探讨溃疡性结肠炎的微生态学改变及双歧杆菌对溃疡性结肠炎的预防和治疗作用。方法 :以 Western大白鼠为模型。结果 :发生溃疡性结肠炎时动物体重、双歧杆菌活菌计数、G+ / G-菌相对数均发生显著性降低 (P>0 .0 1) ,且伴随相关体征、结肠肉眼观察及病理切片检查的恶性改变 ;对照组及预先双歧杆菌灌肠 1周后再行诱导组差异无显著性 (P<0 .0 5 )。结论 :双歧杆菌与常规药物均对溃疡性结肠炎有明显的治疗作用 ,但双歧杆菌治疗作用疗效好于常规药物疗法 ,说明微生态调节剂是防治该病的一种较为理想的方法     

中医药微生态学的研究现状

微生态学 (ｍｉｃｒｏｅｃｏｌｏｇｙ)是 2 0世纪 70年代才崛起的一门新兴的边缘学科。虽然历史很短 ,但发展速猛 ,对医学影响极大。正如有的专家认为 ,微生态学为医学领域带来一系列的观念革命 ,其意义是极其深远的 ;尤其是微生态学的一些基本理论观点和古老的中医药学极为相似 ,一脉相通 ;这是现代医学 ,任何学科所无法比拟的。人们不仅要想 ,为什么一门只有 2 0多年的新兴起的微生态学和具有几千年历史的中医药学 ,一拍即合呢 ?随着中医药微生态学的研究逐渐深入 ,二者的关系会日趋明确 ,中医药微生态学这门中西结合的新兴边缘学科会逐渐…     

微生态学发展的历史轨迹

微生态学的发展几乎是与微生物学同时发生的。早在19世纪末 2 0世纪初 ,微生物学的出现和发展就同时孕育着许多分支 ,其中免疫学、病毒学及原生动物学早已应运而生 ,并且在 2 0世纪初已逐渐形成了独立的新学科。微生态学本来早就应该作为一个新学科来构成生命科学的一个分支 ,但实际上却姗姗来迟 ,这是有历史渊源的。1　鼎足三分微生物学的发展 ,以及后来的微生态学的崛起 ,有三个大人物必须提到。在 19世纪末叶和 2 0世纪初出现了三个划时代的人物 ,这就是法国的巴斯德 (Ｌ .Ｐａｓｔｅｕｒ,182 2 1895 )、俄国的梅奇尼科夫 (Ｅ .Ｍｅｔｃ…     

《在医学生中开展医学微生态学的教学方法研究》体会

随着我国社会主义经济深刻的变化。经济所产生的重大影响。正在逐步地显现出来。科学技术在21世纪将有更快的进步和发展。医学科学与自然科学和生物技术将显现出广泛的交叉渗透。医学教育改革也日趋深入。医学微生态学将成为医学领域中的重要学科,因此在医学生中开设医学微生态学是十分必要的。在医学微生态学十几年的授课过程中,我们深深的体会到大学培养的专门人才不仅需要广博的知识和宽广深厚的基础理论,而且必须有从事现代化建设和适应新的技术革命发展的能力。包括独立探索新知识,善于识别筛选信息。善于灵活调度知识去解决实际问题。这样的人才,才能在激烈的竞争时代立于不败之地。但是如何讲好这门课程是我们医学基础教师所面临的重要课题。下面就把自己的工作体会归纳总结如下。     

Streptomycin-resistant mutant production in a continuous-flow UV mutation device

Summary A continuous-flow UV-induced mutation device which incorporates starting strain cultivation, UV irradiation and mutant reproduction was conceptualized and tested in this study using streptomycin resistance as an indicator of mutant production. For the experimental conditions employed and populations used, the mutation frequency for streptomycin resistance ranged from 10^–4 to 10^–5 cfu/ml. These mutation frequencies are comparable with conventional batch UV mutation methods and represent a gain of 3 orders of magnitude over the spontaneous mutation frequency.     

A continuous-flow method of organ culture

Summary A method of perfusion organ culture is described in which explants cultured at the airmedium interface are bathed by a continuous flow of nutrient medium. Morphological studies on the fetal rat lung indicate that explant development in this system is comparable to that obtained using standard organ-culture dishes. Medium supply is easily manipulated and continuous sampling of the effluent stream is possible without disturbing the immediate explant environment. The basic design facilitates secretory-response studies on cultured organ explants as demonstrated by a study of glucose-stimulated insulin release by the neonatal rat pancreas. This work was supported by U. S. Public Health Service Training Grant No. GM 00114.     

一种新的稀释定量方法在标本检测中的应用

我们使用注射器装入小金属棒在磁力搅拌器上作连续定量稀释方法与传播的吸管或移液器稀释方法,用于含菌量大的粪便标本及含菌量较小的烧伤病人创面和血液标本进行标本细菌的定量分析,结果证实两种方法结果较准确,重复性好,且无统计学差异。     

Molecular integrity of monoclonal antibodies produced by hybridoma cells in batch culture and in continuous-flow culture with integrated product recovery

The molecular integrity of monoclonal antibodies (MCAB) produced by murine hybridoma cell line TB/C3 was studied in batch and continuous-flow cultures. In batch culture, one band of MCAB was detected initially by Western blotting of sodium dodecyl sulfate (SDS)-polyacrylamide gels run under unreduced conditions, but heterogenous MCAB bands appeared as the culture aged. The latter were due to the degradation of MCAB by proteases active at the neutral pH of the culture. The deleterious effect of proteases was minimized in the continuous-flow cultures which were integrated for product recovery. The MCAB of high quality was purified over 26 days from a culture grown at a dilution rate of 0.025 h(-1) (experiment 1). However, at a lower dilution rate of 0.015 h(-1) (experiment 2), the integrity of MCAB was compromised after the initial 13 days of culture. This was shown to be due to the variation in the carbohydrate content of MCAB produced, as judged by the increased sialylation of heavy chains and the varied reactivity of MCAB with lectins (Maackia amurensis agglutinin, Galanthus nivalis agglutinin, and Datura stramonium agglutinin) as the age of the culture increased. The concentration of the purified MCAB samples by enzyme-linked immunosorbent assay (ELISA) (used normally) was usually higher than that estimated by absorbance at 280 nm. Best correlation between the two methods (ELISA-280 nm ratio of 1.02-1.25) was obtained with experiment 1 samples. This ratio increased in experiment 2 and batch culture samples as the heterogeneity of MCAB produced increased, being 1.03-2.94 and 2.53-4.62, respectively. Therefore, ELISA overestimated MCAB concentration when the molecular integrity of the latter was compromised. The ELISA-A(280) nm ratio might hence provide a useful indicator for assessing the quality of MCAB produced. Comparison of SDS-polyacrylamide gels stained with Coomassie Brilliant Blue R and silver showed that the former correlated better with the MCAB activity stain, whereas the silver stained both the protein- and carbohydrate-rich components. Comparison of the patterns produced with these two stains might therefore offer another parameter to monitor the overall integrity of MCAB produced. Finally, the data presented have important implications on the validity of using long-term and intensive cultures for generating MCAB because such cultures would be subjected to the additive effects reported for batch and continuous modes of growth. (c) 1993 John Wiley & Sons, Inc.     

Phosphate-limited growth of Chromatium vinosum in continuous culture

Chromatium vinosum DSM 185 was grown in continuous culture at a constant dilution rate of 0.071 h^-1 with sulfide as the only electron donor. The organism was subjected to conditions ranging from phosphate limitation (S _R-phosphate=2.7 M and S _R-sulfide=1.8 mM) to sulfide limitation (S _R-phosphate=86 M and S _R-sulfide=1.8 mM). At values of S _R-phosphate below 7.5 M the culture was washed out, whereas S _R-phosphate above this value resulted in steady states. The saturation constant (K ) for growth on phosphate was estimated to be between 2.6 and 4.1 M. The specific phosphorus content of the cells increased from 0.30 to 0.85 mol P mg^-1 protein with increasing S _R-phosphate. The specific rate of phosphate uptake increased with increasing S _R-phosphate, and displayed a non-hyperbolic saturation relationship with respect to the concentration of phosphate in the inflowing medium. Approximation of a hyperbolic saturation function yielded a maximum uptake rate (V _max) of 85 nmol P mg^-1 protein h^-1, and a saturation constant for uptake (K _t) of 0.7 M. When phosphate was supplied in excess 8.5% of the phosphate taken up by the cells was excreted as organic phosphorus at a specific rate of 8 nmol P mg^-1 protein h^-1.Non-standard abbreviations BChla bacteriochlorophyll a - D dilution rate; _max, maximum specific growth rate - maximum specific growth rate if the substrate were not inhibitory - K saturation constant for growth on phosphate - V _max maximum rate of phosphate uptake - K _i saturation constant for phosphate uptake - K _i inhibition constant for growth in the presence of sulfide - S _R concentration of substrate in the inflowing medium     

大蒜多糖对小鼠肠道微生态的益生元功能研究

目的评估大蒜多糖的益生元功能。方法以不同剂量的大蒜多糖灌胃健康雌性昆明小鼠,并以菊糖为阳性对照,采用微生物选择性培养分析和T-RFLP技术分析大蒜多糖对小鼠肠道微生态的影响,同时利用全自动血细胞分析仪来分析小鼠血脂代谢指标。结果连续灌胃21 d后,大蒜多糖和菊糖能够改善小鼠肠道微生态菌群,其中双歧杆菌数量显著增加（P〈0.01）,肠杆菌数量显著下降（P〈0.05）,而类杆菌的数量变化差异无统计学意义,T-RFLP结果也表现出同样的变化趋势。不同实验组小鼠血清中胆固醇及甘油三酯的含量和鼠胸腺和脾脏的重量与体重的比值差异无统计学意义,说明大蒜多糖对小鼠的免疫系统无副作用。结论本实验初步证实了大蒜多糖具有益生元功效。     

A continuous-flow culture system for organ culture of large explants of adult tissue: Effect of oxygen tension on mouse molar periodontium

Summary A modified continuous-flow culture system (CFCS) was developed to maintain large explants of periodontium from adult mouse in organ culture. The culture medium was stored in a reservoir outside of the incubator, pumped via polyvinyl tubing into small glass culture chambers that were placed in the oxygenator and then collected in a waste flask. Medium was analyzed for pO₂, pCO₂ and pH during the culture period. Three-molar and singlemolar explants of periodontium were maintained for 48 hr in the CFCS at two different pO₂ ranges: 100 to 120 mm Hg and 400 to 420 mm Hg. [³H]Proline was added 24 hr prior to sacrifice. Light-microscope morphological and radioautographic observations suggested that cell viability and incorporation of [³H]proline, probably into newly synthesized protein, increased with an increase in pO₂ and was related to a pO₂ gradient extending from the periphery to the center of the explants.     

Continuous culture of Methanococcus maripaludis under defined nutrient conditions

To study global regulation in the methanogenic archaeon Methanococcus maripaludis, we devised a system for steady-state growth in chemostats. New Brunswick Bioflo 110 bioreactors were equipped with controlled delivery of hydrogen, nitrogen, carbon dioxide, hydrogen sulfide, and anaerobic medium. We determined conditions and media compositions for growth with three different limiting nutrients, hydrogen, phosphate, and leucine. To investigate leucine limitation we constructed and characterized a mutant in the leuA gene for 2-isopropylmalate synthase, demonstrating for the first time the function of this gene in the Archaea. Steady state specific growth rates in these studies ranged from 0.042 to 0.24 h(-1). Plots of culture density vs. growth rate for each condition showed the behavior predicted by growth modeling. The results show that growth behavior is normal and reproducible and validate the use of the chemostat system for metabolic and global regulation studies in M. maripaludis.     

Ecophysiology of associative nitrogen fixation in a rhizosphere model in pure and mixed culture

Abstract A gradostat (multistage chemostat) was used as a model of the rhizosphere. Investigations of the influence of NH₄Cl and O₂ gradients on a diazotrophic rhizosphere bacterium in pure culture and in mixed culture with non-diazotrophic strains were carried out. The diazotrophic isolate was able to grow on N₂ and NH₄Cl simultaneously. The diazotrophic isolate could successfully compete with the non-diazotrophic isolates in the presence and absence of NH₄Cl in most experiments. Only minor amounts of nitrogen were transferred to the non-fixing organisms. A concept of transfer of nitrogen to non-fixing organisms is proposed.     

Technology for cell cycle research with unstressed steady-state cultures

A culture system for performing cell cycle analyses on cells in undisturbed steady-state populations was designed and tested. In this system, newborn cells are shed continuously from an immobilized, perfused culture rotating about the horizontal axis. As a result of this arrangement, the number of newborn cells released into the effluent medium each generation is identical to the number of cells residing in the immobilized population, indicating that one of the two new daughter cells is shed at each cell division. Thus, the immobilized cells constitute a continuous, steady-state culture because the concentrations, locations and microenvironments of the cells in the culture vessel do not vary with time. In tests with mouse L1210 lymphocytic leukemia cells, about 10⁸ newborn cells were produced per day. This new culture system enables a multiplicity of cell cycle analyses on large numbers of cells assured to be from populations in steady-state growth.