Search results for "Soil microbiology"
showing 10 items of 213 documents
Microbial community structure in soils with decomposing residues from plants with genetic modifications to lignin biosynthesis
2006
Lignin is a major determinant of the decomposition of plant materials in soils. Advances in transgenic technology have led to the possibility of modifying lignin to improve the pulping properties of plant materials for papermaking. Previous studies have shown that lignin modifications also affect the rate of plant material decay in soil. The aim of this work was to investigate short-term changes in soil microbial community structures when tobacco residues with reduced activity of enzymes in the monolignol pathway decompose. The residues from lignin-modified plants all decomposed faster than unmodified plant materials. The relative proportions of some of the structural groups of microbial ph…
Heterogeneity of carbon loss and its temperature sensitivity in East-European subarctic tundra soils
2016
Arctic peatlands store large stocks of organic carbon which are vulnerable to the climate change but their fate is uncertain. There is increasing evidence that a part of it will be lost as a result of faster microbial mineralization. We studied the vulnerability of 3500-5900 years old bare peat uplifted from permafrost layers by cryogenic processes to the surface of an arctic peat plateau. We aimed to find biotic and abiotic drivers of CLOSS from old peat and compare them with those of adjacent, young vegetated soils of the peat plateau and mineral tundra. The soils were incubated in laboratory at three temperatures (4°C, 12°C and 20°C) and two oxygen levels (aerobic, anaerobic). CLOSS was …
Methanotrophy induces nitrogen fixation during peatland development
2013
Significance In peatlands, the external sources of nitrogen are mainly atmospheric, but the atmospheric nitrogen deposition alone cannot explain the long-term annual nitrogen accumulation rates to these ecosystems. Because of methodological problems, methane-induced fixation of atmospheric dinitrogen gas has been previously overlooked as an additional nitrogen input mechanism. We found that the activity of methane-oxidizing bacteria provides not only carbon but also nitrogen to peat mosses and, thus, contributes to carbon and nitrogen accumulation in peatlands, which store approximately one-third of the global soil carbon pool. Our results imply that nitrogen fixation in wetlands may be str…
Abundant and diverse arsenic‐metabolizing microorganisms in peatlands treating arsenic‐contaminated mining wastewaters
2020
Mining operations produce large quantities of wastewater. At a mine site in Northern Finland, two natural peatlands are used for the treatment of mining‐influenced waters with high concentrations of sulfate and potentially toxic arsenic (As). In the present study, As removal and the involved microbial processes in those treatment peatlands (TPs) were assessed. Arsenic‐metabolizing microorganisms were abundant in peat soil from both TPs (up to 108 cells gdw‐1), with arsenate respirers being about 100 times more abundant than arsenite oxidizers. In uninhibited microcosm incubations, supplemented arsenite was oxidized under oxic conditions and supplemented arsenate was reduced under anoxic con…
The ability of soil-borne fungi to degrade organophosphonate carbon-to-phosphorus bonds
1997
The ability of a wide variety of soil-borne fungal strains to degrade four structurally different compounds containing P-C bonds, namely the naturally occurring amino acid ciliatine, the popular herbicide glyphosate, phosphonoacetic acid and 2-amino-3-phosphonopropionic acid, was studied in order to show that soil fungi may play an important role in the biodegradation of organophosphonates. Most of the strains appeared to utilize ciliatine as the sole source of phosphorus for growth. Only a limited number of strains were able to grow on the other phosphonates used in this work. The strains of Trichoderma harzianum, Scopulariopsis sp. and Aspergillus niger chosen for more detailed study show…
Coupling geochemical, mineralogical and microbiological approaches to assess the health of contaminated soil around the Almalyk mining and smelter co…
2013
This study describes the impact of airborne pollution resulting from mining and smelting activities on the soils of the Almalyk mining and industrial area (NE Uzbekistan). Samples were collected along a transect downwind of the industrial area. Enriched contents of some metals were found in the upper soil layers near the metallurgical complex (Zn≤3010 mg kg(-1), Pb≤630 mg kg(-1), Cd≤30 mg kg(-1)) which suggests that these metals were derived from local stack emissions. The morphology and internal microstructure of metal-bearing spherical particles found in the heavy mineral fraction suggest that these particles were probably a result of inefficient flue gas cleaning technique of the smelter…
Potential for microbial diuron mineralisation in a small wine-growing watershed: from treated plots to lotic receiver hydrosystem
2009
BACKGROUND: Since biological degradation processes are known to be a major driver of the natural attenuation of pesticide residues in the environment, microbial communities adapted to pesticide biodegradation are likely to play a key environmental role in reducing pesticide exposure in contaminated ecosystems. The aim of this study was to assess the diuron-mineralising potential of microbial communities at a small-scale watershed level, including a diuron-treated vineyard (pollution source), its associated grass buffer strip (as a river protection area against pesticide runoff) and the lotic receiver hydrosystem (sediments and epilithon), by using radiorespirometry. RESULTS: Comparison of r…
Isolation and partial characterization of antagonistic peptides produced by Paenibacillus sp. strain B2 isolated from the sorghum mycorrhizosphere.
2005
ABSTRACT Paenibacillus sp. strain B2, isolated from the mycorrhizosphere of sorghum colonized by Glomus mosseae , produces an antagonistic factor. This factor has a broad spectrum of activity against gram-positive and gram-negative bacteria and also against fungi. The antagonistic factor was isolated from the bacterial culture medium and purified by cation-exchange, reverse-phase, and size exclusion chromatography. The purified factor could be separated into three active compounds following characterization by amino acid analysis and by combined reverse-phase chromatography and mass spectrometry (liquid chromatography-mass spectrometry and mass spectrometry-mass spectrometry). The first com…
Microbiological control of soil-borne phytopathogenic fungi with special emphasis on wilt-inducing Fusarium oxysporum
2009
Contents Summary 529 I. Biological control of plant diseases: state of the art 530 II. Main modes of action of biological control agents 530 III. The protective strains of F. oxysporum: an unexplored model 532 IV. Future directions for the study of the protective capacity of strains of F. oxysporum 539 V. How to make biological control successful in the field? 540 References 541 Summary Plant diseases induced by soil-borne plant pathogens are among the most difficult to control. In the absence of effective chemical control methods, there is renewed interest in biological control based on application of populations of antagonistic micro-organisms. In addition to Pseudomonas spp. a…
Proteomics as a tool to monitor plant-microbe endosymbioses in the rhizosphere
2004
In recent years, outstanding molecular approaches have been used to investigate genes and functions involved in plant-microbe endosymbioses. In this review, we outline the use of proteomic analysis, based on two-dimensional electrophoresis and mass spectrometry, to characterize symbiosis-related proteins. During the last decade, proteomics succeeded in identifying about 400 proteins associated with the development and functioning of both mycorrhizal and rhizobial symbioses. Further progress in prefractionation procedures is expected to allow the detection of symbiotic proteins showing low abundance or being present in certain cell compartments.