Copper-resistant microorganisms and their role in the environment

Naturally occurring, copper-resistant microorganisms are common in the environment. This review discusses the mechanism of copper resistance, which is not yet clearly understood, though the copper resistance conferred by a plasmid pPT23D has been elucidated at the molecular level. The different applications of copper-resistant microorganisms are described, including commerical bloleaching of copper ores. The construction of novel bioleaching strains through recombinant DNA technology may be possible. Biosorbents, the non-living microbial blomass, have been successfully used for metal recovery operations and are also reviewed.     

GTP-cyclohydrolases of microorganisms and their role in metabolism

The properties, regularities of biosynthesis and biochemical functions are considered of GTP-cyclohydrolases of microorganisms. The existence of two groups of these enzymes is established. The first group enzymes convert GTP into 7,8-dihydroneopterin-triphosphate and formiate. They participate in biosynthesis of tetrahydrofolic acid, tetrahydrobiopterin, molybdenic cofactor, pyrrolopyrimidine antibiotics and in a series of pigments. Representatives of the second group of cyclohydrolases convert GTP into 2,5-diamino-4-oxy-6-ribosylaminopyrimidine-5'-phosphate, formiate and pyrophosphate. They catalyze the first stages of formation of 6,7-dimethyl-8-ribityllumazine, flavins and their derivatives, toxoflavin (azapteridine antibiotics). The regulation of biosynthesis and activity of GTP-cyclohydrolases is studied only for individual enzymes of this group.     

Possible role of soil microorganisms in aggregation in soils

In many soils, roots and fungal hyphae, especially those of vesicular arbuscular mycorrhizal (VAM) fungi, stabilize macroaggregates (>250 μm diameter); organic residues, bacteria, polysaccharides and inorganic materials stabilize microaggregates (<250 μm). This review discusses the factors (including other organisms) which affect VAM hyphae and their extracellular polysaccharides in soil, and the subsequent effect on stability of aggregates. The review also discusses the possible role of other organisms, including ectomycorrhizal fungi, in the stability of soil, and suggests future research.     

Taxonomic characteristics of soil Mycobacteria and their antibiotic properties]

Morphological, cultural and chemotaxonomic properties of 12 gram-positive soil cultures isolated were studied by using a test system developed for screening the organisms producing broad-spectrum antibiotics among Nocardiaforms (Coryneforms). The cultures were found to belong to Actinomycetales, Nocardioforms, Mycobacteriaceae and Mycobacterium. The saprophytic rapidly growing soil mycobacteria showed antibiotic activity against a large number of gram-positive and gram-negative test microbes including those belonging to Pseudomonas and Proteus resistant to the majority of the antibiotics currently used in medicine.     

Taxonomic position of the genus Mycococcus

An attempt to elucidate the taxonomic position of the genera Mycococcus has been made. For this purpose the full range of the taxonomically important properties were investigated among microbial cultures preliminary identified as Mycococci. As a result of comparison Mycococcus with Micrococcus the taxonomic status of the genus Mycococcus was no longer confirmed. On the grounds of the published data and the author's experimental results it was concluded that genus Micrococcus was closely related to genus Arthrobacter. The possibility to place the genus Micrococcus within the group of coryneform bacteria is being discussed.     

Effect of the insecticide actellic on soil microorganisms and their activity

The insecticide Actellic or its active component pirimiphosmethyl affected the growth and reproduction of some soil bacteria and fungi, fixation of atmospheric nitrogen, nitrification and overall soil metabolic activity. Both bacterial growth and the activities under study were negatively influenced by high concentrations of the agent (as compared with actual pirimiphosmethyl concentrations routinely used in agriculture) whereas lower concentrations stimulated the overall metabolic soil activity.     

Effect of the herbicide bentanex on soil microorganisms and their activity

The effect of the herbicide Bentanex, especially of its effective component bentazone, on selected soil bacteria and fungi, on their growth and reproduction and on some important physiological activities ensuring a regular nutrient cycle in nature was investigated. Bentazone affected growth and reproduction of soil bacteria and micromycetes in dependence on the concentration and species of the microorganism. Physiological and biochemical activities of bacteria with respect to nitrogen fixation, nitrification and CO₂ production were negatively influenced by high concentrations of the herbicide. These concentrations were used to observe the effect on selected activities of soil microorganisms and were much higher than those actually used in agriculture. Translated by Č. Novotny     

Taxonomic position of some rana species in a dendrogram from their globin composition

• 1.1. The aminoacidic composition of the globin of the genus Rana has been analyzed.
• 2.2. The resulting data and those from five other species of Ranidae, from one species of Pipidae and one of Bufonidae having been compared in pairs according to the formula of Harris and Teller gave origin to a “dissimilarity matrix”.
• 3.3. In a “Phylo” computer program, consistent with Moore's model, the data of the input matrix have been used to find the mutual taxonomic relations of the 11 anuran species examined.

     

Insecticidal effects on soil microorganisms and their biochemical processes related to soil fertility

Among the four insecticides under study, hexachlorocyclohexane (BHC) followed by phorate significantly stimulated the populations of (total) bacteria, actinomycetes, fungi, aerobic non-symbiotic N2-fixing bacteria and P-solubilizing microorganisms in soil. Carbofuran significantly stimulated total as well as N2-fixing bacteria. Fenvalerate had no effect on P-solubilizers. All the insecticides stimulated the proportion of Penicillium in soil. Similarly, Pseudomonas with BHC, Sarcina with phorate, Corynebacterium, Azotobacter and Streptomyces with fenvalerate were also stimulated. On the other hand, Erysipelothrix with BHC, Staphylococcus with phorate, Staphylococcus, Nocardia and Fusarium with fenvalerate were inhibited. Almost all the insecticides reduced the proportions of Micrococcus and Rhizopus in soil. Insecticides also augmented the non-symbiotic N2-fixing and P-solubilizing capacities of the soil and the augmentation was more pronounced with BHC followed by phorate.     

土壤矿物与微生物相互作用的机理及其环境效应

土壤矿物与微生物相互作用是地球表层系统中重要的生态过程.微生物或生物分子与矿物间的吸附(粘附)是两者相互作用的基础.吸附(粘附)是一个由分子间力、静电力、疏水作用力、氢键和空间位阻效应等多种作用力或作用因素共同决定、影响的物理化学过程.因此,微生物和矿物的表面性质如表面电荷、疏水性和它们所处的环境条件如pH、电解质浓度、温度等,都影响着矿物-微生物吸附(粘附)过程.微生物细胞或酶可吸附于矿物表面,其结果是细胞代谢或酶活性会发生明显变化,并进一步影响土壤中诸多相关的生态、环境过程.结合4种典型的初始吸附理论:表面自由能热力学理论、DLVO理论、吸附等温线理论和表面复合物理论及本课题组近年来的研究成果,对土壤矿物与微生物相互作用的类型、机理、作用力和现代研究技术等方面的最新研究进展进行了较为全面的论述,对土壤矿物-微生物相互作用的环境效应进行了讨论,并就该领域今后研究工作的特点及应关注的问题进行了展望.     

Taxonomic identification of gram-negative nonfermenting microorganisms in environmental research

The scheme for the identification of Gram-negative nonfermenting microorganisms is proposed. The scheme comprises the most important key signs, such as the cytochrome oxidase reaction determined by the method of Gaby and Hadley, the oxidation/fermentation test, maltose oxidation and motility, as well as additional key signs, among them gelatinase activity, the oxidation of 10% lactose, nitratase activity with the liberation of free nitrogen, the utilization of the sources of carbon and energy (glucose and sodium acetate) in limited media containing ammonium salts and nitrates as the sources of nitrogen. Additional tests for the identification of nonfermenting microorganisms similar in their main key signs are also recommended.     

酸性土壤氨氧化微生物及其影响因素研究进展

自然条件变化和人类活动不仅加剧了土壤酸化,扩大了酸性土壤面积,而且严重影响了土壤氮循环。氨氧化过程作为硝化作用的限速步骤,是全球氮循环的核心环节,受到国内外研究者的广泛关注。探究酸性土壤氨氧化作用及其功能微生物对完善氮循环机制和促进土壤养分循环具有重要意义。本文主要综述了土壤中氨氧化代谢途径,对比了氨氧化细菌(ammoniaoxidizing bacteria, AOB)、氨氧化古菌(ammonia-oxidizing archaea, AOA)和全程硝化菌(complete ammoniaoxidizers,Comammox)对酸性土壤氨氧化作用的相对贡献,分析了微生物内源功能差异及pH、底物浓度等外部环境因素对氨氧化微生物丰度、活性和群落结构的影响,最后对氨氧化微生物研究进行了展望,以期为酸性土壤氨氧化作用研究和微生物修复技术应用与实践提供科学参考。     

The role of microorganisms in transformations of sulphite in spruce forest soil

Transformations of sulphite and the participation of microorganisms were investigated in samples of fermentative (A₀₂) and humus (A₀₃) horizons from a spruce forest. About 80% of sulphite were almost immediately oxidized abiotically to sulphate, less than 1% persisted in the soil for several days and almost 20% were converted to a form not demonstrable as sulphite or sulphate. Microorganisms accelerated the disappearance of less than 10% of the added sulphite.     

玛咖在中国独荇菜属中的定位

建立了15种中国独荇菜属植物和秘鲁原产的玛咖的性状矩阵,并采用SPSSV11．0软件建立了树谱图,以此检验《中国植物志》有关该属植物形态学分类的正确性,同时确立玛咖与该属其他植物之间的相互亲缘关系,为研究玛咖的育种、栽培提供理论依据。     

Taxonomic position of the lysine producer Brevibacterium flavum

Brevibacterium flavum 22 and 22L producing lysine and glutamic acid should be reclassified as Corynebacterium glutamicum on the basis of their chemotaxonomic characteristics: the IV type of the cell wall, corynomycolic acids C32--C34, 57.8% of GC in DNA.     

The role of microorganisms in mediating and facilitating the uptake of plant nutrients from soil

Summary No root systems in nature are without a microbial population. These may be freeliving or symbiotic.The incidence and nutrition of the freeliving microorganisms is discussed. Shortage of substrate makes it unlikely that the N-fixers in the population can fix useful amounts of N. There is a possibility that P supply is improved, but an analysis of possible processes shows them to be rather unlikely, and evidence for them to be poor. Manganese and iron uptake can be altered by microbial activity. Growth of plants can be affected by non-nutritional bacterial effects.The ecology of Rhizobium in the soil is briefly discussed, and the varying needs of different identified strains is stressed.Mycorrhizal infection of plants leads to large growth increases in appropriate conditions. This is almost always linked to increased P uptake, but zinc and copper nutrition can also be improved. The processes involved are briefly discussed. Rapid and extensive infection is important; it is very sensitive to temperature. New modelling methods are now becoming available to measure the behaviour of the fungal infections. The microorganisms require C compounds from the plant, and new measurements of this cost are discussed. The possibility of practical use of mycorrhizal fungi seem to be improving.Keynote address