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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
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
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
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
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
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
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
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
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
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
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
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.
Applications of quantitative gas chromatography/mass spectrometry (selected ion monitoring) to clinical and ecological microbiology are described. The technique permits determination of selected microbial metabolites and can be used for the rapid diagnosis of, for example, tuberculosis by ion-focusing of specific branch-chain fatty acids. The technique is also used to determine diaminopimelic and
Saturated, monoenoic and β-hydroxysubstituted fatty acids, 13C-labelled at the carboxyl group, were prepared from natural or synthetic unlabelled analogues. The synthetic route involves decarboxylation of the unlabelled fatty acid to the next lower iodide, displacement of iodide for [13C]cyanide and hydrolysis. The fatty acids were converted to their pentafluorobenzyl esters and analysed by select
The isopod Oniscus asellus was fed wood pieces. The fecal pellets produced during 6 days were reingested twice. Both fresh and ageing pellets were examined for microorganisms and nitrogen compounds including proteins and bacterial cell wall compounds, d-alanine and diaminopimelic acid. In old pellets, the plate counts of fungi decreased but that of bacteria as well as the concentrations of protein
Male and female flowers of the dioecious perennial herb Rubus chamaemorus L. are similar in general appearance. However, female flowers are somewhat smaller, do not produce any pollen, and contain very small amounts of nectar. Syrphids and bumblebees, which are important pollinators of R. chamaemorus, showed a strong preference for male flowers. Male flowers were also less often rejected by flower
An autoclavable all-glass system for studying microbial dynamics at permeable surfaces is described. Standard hydrophobic or hydrophilic membranes (46-mm diameter) of various pore sizes were supported on a glass frit through which nutrient solutions were pumped by a peristaltic pump. The pump provided a precisely controlled flow at speeds of 0.5 to 500 ml of defined or natural cell exudates per h,
Qualitative and quantitative changes were observed in lipids, poly-β-hydroxybutyrate (PHB), and a cell wall peptidoglycan consitutent in a marine bacterial isolate during starvation for 24 h in an energy and nutrient-free medium. While the amount and composition of the membrane fatty acids fluctuated within the first hours of starvation, the total amount of fatty acids decreased during the starvat
Three marine bacteria were examined for physiological and morphological changes in the initial phase of starvation. It was found that the starvation process was induced in a similar way irrespective of whether the cells were suspended in nutrient and energy free artificial seawater (NSS) or NSS supplemented with nitrogen and phosphorus. An initial phase of increased activity was consistent with a
