Mk8

Gram-negative bacteria (Proteus, Enterobacter)

MK-10(H6), MK-10(H8) Gram-positive bacteria, Streptomycineae, Micromonosporinae in the Class of Actinobacteria MK-10, MK-11, MK-12 Gram-positive bacteria (Agrococcus, Aureobacterium, Microbacterium)

MK-10(H6), MK-10(H8) Gram-positive bacteria, Streptomycineae, Micromonosporinae in the Class of Actinobacteria MK-10, MK-11, MK-12 Gram-positive bacteria (Agrococcus, Aureobacterium, Microbacterium)

aAdapted from Fujie et al. (1998), Katayama and Fujie (2000), and Hu et al. (2001).

of soils indicates the extent of fungal membranes as well as fungal and ecto-mycorrhizal biomass. Ergosterol is extracted by methanol and detected using highperformance liquid chromatography with a UV detector. Since chromatographic coelution might be a problem, reversed-phase liquid chromatography with positive-ion atmospheric pressure chemical ionization tandem mass spectrometry can be used for full quantification and confirmation of ergosterol (Verma et al., 2002). The ergosterol content varies from 0.75 to 12.9 ^g soil in arable, grassland, and forest soils. These values correspond to 5 to 31 mg ergosterol fungal dry weight depending on species and growth conditions. The ratio of ergosterol to microbial biomass C is used as an index for fungal biomass to the total soil micro-bial biomass. Shifts in microbial community structure due to soil contamination or changes in vegetation can be detected using the ergosterol to microbial biomass C ratio. In addition, the content of coprostanol, which is a sterol present after sewage sludge disposal and contamination by municipal wastes, is a useful marker of human fecal matter contamination of soils.

LIPOPOLYSACCHARIDES, GLYCOPROTEINS, AND CELL WALLS

The outer cell membrane of G~ bacteria contains unique lipopolysaccharide polymers that can be used as biomarkers. The peptidoglycan of bacterial cell walls contains N-acetylmuramic acid and diaminopimelic acid. Chitin, a polymer of N-acetylglucosamine, is found in many fungi. This compound is also present in the exoskeleton of invertebrates. The usefulness of chitin assays is limited by the need for acid hydrolysis prior to analysis, the variability in the amount present, the presence of chitin in a wide variety of other organisms, and its accumulation in nonbiological soil components.

Arbuscular mycorrhizal fungi contain a recalcitrant AMF-specific glycoprotein, glomalin, in their cell walls, which can be quantified operationally in soils as glo-malin-related soil protein (Driver et al., 2005). An indirect immunofluorescence assay is described by Wright (2000) to detect glomalin on AMF hyphae attached to roots, in roots, on hyphae, and on the surfaces of soil aggregates. Since gloma-lin is a recalcitrant compound, this glycoprotein cannot be used as a signature molecule for living AMF.

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