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A multispecific saline-soluble lectin from the parasitic fungus Arthrobotrys oligospora : Similarities in the binding specificities compared with a lectin from the mushroom Agaricus bisporus

Several fungi can express high levels of saline-soluble and low- molecular-mass lectins that bind to glycoproteins such as fetuin and different mucins but not bind to any monosaccharides. In this paper, we report the binding specificities of such a lectin (designated AOL) isolated from the nematophagous fungus Arthrobotrys oligospora. The results show that AOL is a multispecific lectin that intera

Sequence analysis and regulation of a gene encoding a cuticle-degrading serine protease from the nematophagous fungus Arthrobotrys oligospora

The nematode trapping fungus Arthrobotrys oligospora produces an extracellular serine protease (designated PII) that immobilizes free-living nematodes in bioassays and hydrolyses proteins of the nematode cuticle. Peptides were isolated from PII and partly sequenced. Three internal peptide sequences were used to design synthetic oligonucleotides, which allowed the subsequent isolation of the gene e

Changes in microbial community structure during long-term incubation in two soils experimentally contaminated with metals

The effects of Zn contamination on the microbial community structure of a forest humus and an arable soil, as estimated by phospholipid fatty acid (PLFA) analysis, were followed during 18 months. The soils were contaminated at 10 different metal concentrations and incubated in plastic jars at 22°C. In both soils effects of heavy metal contamination could be detected after 2 weeks. Qualitatively si

Bacterial communities in peat in relation to botanical composition as revealed by phospholipid fatty acid analysis

Analysis of phospholipids extracted from various moss and sedge peat types revealed significant differences in the patterns of the phospholipid fatty acids (PLFA) with respect to the major botanical constituents of the peats. Principal component analysis of the PLFA data showed that peats dominated by Carex residues had higher relative amounts of cyclopropane fatty acids and cis vaccenic fatty aci

Purification and characterization of an extracellular serine protease from the nematode-trapping fungus Arthrobotrys oligospora

When grown in liquid cultures allowing the formation of nematode traps, the fungus Arthrobotrys oligospora produced two extracellular proteases hydrolysing the chromogenic substrate Azocoll. The protease activity was separated into two fractions (FI and FII) using anion-exchange chromatography. In bioassays, protease(s) present in FII immobilized the free-living nematode Panagrellus redivivus indi

Phospholipid fatty acid composition, biomass, and activity of microbial communities from two soil types experimentally exposed to different heavy metals

The phospholipid fatty acid (PLFA) pattern was analyzed in a forest humus and in an arable soil experimentally polluted with Cd, Cu, Ni, Pb, or Zn at different concentrations. In both soil types, there were gradual changes in the PLFA patterns for the different levels of metal contamination. The changes in the forest soil were similar irrespective of which metal was used, while in the arable soil

Monitoring microbiol adhesion and biofilm formation by attenuated total reflection/Fourier transform infrared spectroscopy

A major problem in accurately defining bacterial adhesion mechanisms and processes occurring in biofilms on surfaces is the lack of techniques that nondestructively provide on-line information about the microorganisms, their extracellular polymers, and metabolites. The attenuated total reflectance (ATR) technique of Fourier transform infrared spectroscopy (FT-IR) is ideally suited to monitor molec

Purification and characterization of a surface lectin from the nematode-trapping fungus Arthrobotrys oligospora

Several studies have indicated that the capture of nematodes by the nematophagous fungus Arthrobotrys oligospora is mediated by a lectin on the fungal surface. One of the major surface proteins of this fungus showed haemagglutinating activity and was isolated by affinity chromatography using a mucin Sepharose column. Biochemical analysis showed that the protein was a dimeric glycoprotein with a mo

Fungal attachment to nematodes

The adhesion mechanisms in three nematophagous fungi are reviewed. In all these fungi the infection and subsequent digestion of nematodes is initiated by the firm adhesion of the fungus to the nematode surface. In Arthrobotrys oligospora the adhesive phase is restricted to special three-dimensional structures. Drechmeria coniospora conidia attach to the nematode cuticle by an adhesive bud while Ca

Proteases and their involvement in the infection and immobilization of nematodes by the nematophagous fungus Arthrobotrys oligospora

The nematophagous fungus Arthrobotrys oligospora produced extracellular proteases when grown in a liquid culture, as revealed by measuring the hydrolysis of the chromogenic substrate Azocoll. The extracellular protease activity was inhibited by phenylmethylsulfonyl fluoride (PMSF) and other serine protease inhibitors and partly inhibited by the aspartate protease inhibitor pepstatin and by a cyste

Laboratory study of chemical speciation of mercury in lake sediment and water under aerobic and anaerobic conditions

Chemical speciation and partitioning of radiolabeled HgCl2 were studied in model aquatic systems consisting of undisturbed entrophic lake sediment and water in plastic cylinders. The cylinders were either gradually made anaerobic by a gentle flow of N2-CO2 or kept aerobic by air flow. The proportion of methylated 203Hg was significantly higher, in both water and sediment, in the anaerobic systems

Microbial biomass measured as total lipid phosphate in soils of different organic content

The use of total lipid phosphate as a measure of biomass was evaluated in soils with different organic matter content. Lipids were extracted with a one-phase mixture of chloroform, methanol, and a buffer, and digested with either persulfate or perchloric acid to liberate lipid-bound phosphate. This procedure was evaluated by varying the extraction buffer, the extraction and digestion times, the am

Measurement of phospholipid fatty acids at picomolar concentrations in biofilms and deep subsurface sediments using gas chromatography and chemical ionization mass spectrometry

Examination of ester-linked phospholipid fatty acids (PLFA) have provided a means to characterize the community structure of microbial assemblies. Attempts to analyze such acids at low picomolar levels in environmental samples by gas chromatography and chemical ionization mass spectrometry (CIMS) using positive or negative ion detection, showed that the limit of detection (LOD) was mainly dependen

Sexual dimorphism and between-year variation in flowering, fruit set and pollinator behaviour in a boreal willow

In Salix myrsinifolia-phylicifolia, males and females produced approximately the same number of catkins per individual, but males produced more flowers per catkin. Females had a higher concentration of sugars in the nectar than males, but the standing crop of nectar did not differ between sexes. Females had a hexoserich nectar, males a sucrose-dominated nectar. Bumblebees discriminated between mal

Surface polymers of the nematode-trapping fungus Arthrobotrys oligospora

The nematophagous fungus Arthrobotrys oligospora captures nematodes using adhesive polymers present on special hyphae (traps) which form a three-dimensional network. To understand further the adhesion mechanisms, A. oligospora surface polymers were visualized by transmisson electron microscopy and characterized by chemical methods. Both traps and hyphae were surrounded by a fibrillar layer of extr

Infrared monitoring of the adhesion of Catenaria anguillulae zoospores to solid surfaces

Electron microscopic studies of nematodes infected with the chytridiomycetous fungusCatenaria anguillulae indicated that zoospores of the fungus adhered to the cuticle of nematodes by a layer of extracellular polymers. The chemical composition of the adhesive polymers and their interaction with a solid surface were examined with Fourier transform infrared spectroscopy, using an attenuated total re

Importance of leaf litter fragmentation for bacterial growth

Four fragment size groups of maple leaf litter (Acer platanoides) were leached with sterile water. The fragments and leachates were inoculated with bacteria isolated from maple leaf litter and bacterial activity and growth were determined. About 80-90% of the dissolved organic carbon (DOC) released from the leaf fragments was released during the 1st day; the release was negatively correlated with

Analysis of carbon steels affected by bacteria using electrochemical impedance and direct current techniques

The failure of metal structures in contact with natural, untreated waters is frequently ascribed to bacterial corrosion. This study compares the corrosive effects of Vibrio natriegens (V. natriegens) when in batch and continuous flow culture. Evidence is presented for enhanced corrosion of carbon steel resulting from aerobic culture of V. natriegens with two sulfate-reducing bacteria (SRB). The co

Growth of bacteria in the rhizoplane and the rhizosphere of rape seedlings

The growth of 10 isolates of rhizosphere bacteria was compared in the rhizoplane (RP), rhizosphere (RS) and non-rhizosphere soil of a model system with rape seedlings growing in sterile sand. The colonization of the RP differed little among isolates. However, the bacterial isolates differed according to their degree of dependence on the root for growth, as judged by RS:RP and plant:non-plant ratio

Differences in lipid composition between free-living and initially adhered cells of a Gram-negative bacterium

The phospholipid fatty acid composition and poly-β-hydroxybutyrate (PHB) content of initially adhered and free-living cells of a Pseudomonas sp. isolated from the rape plant Brassica napus were examined with gas chromatography (GC). Five different adhesion experiments were made including variations in surface charge (hydrophilic and lipophilic), temperature, media composition and time of adhesion.