Pre-marketing assessments of chemicals regarding their potential environmental impacts contain numerous sources of error and uncertainties. Practices and methods for the evaluation of environmental risks posed by individual pre-selected agents seem unsuitable for detecting unexpected trends in the environment. This is particularly so in view of the multitude of anthropogenic assaults on the environment and their complex interactions. Therefore, requirements for symptom-oriented biological effect-test systems, 'bioprobes', capable of reacting sensitively to environmental changes of unknown origin were conceived. Bioprobes designed to detect biological effects should respond to a broad spectrum of anthropogenic chemicals. They are environmental quality measuring devices consisting of cultivated organisms, cells, organelles or biomolecules in combination with recording units. In contrast to traditional biotests for chemical testing, bioprobes are deliberately exposed to selected segments of the environment for certain periods of time. During and after such exposures, changes of defined biological states or process rates-'observation elements'-are registered.

The primary structure of the peptidoglycan and the teichoic acids of two coryneform isolates from the surface flora of French cooked cheeses, C N R Z 925 and C N R Z 926, have been determined. In the peptidoglycan, meso-diaminopimelic acid was localized in position three of the peptide subunit. It contained an D-glutamyl-D-aspartyl interpeptide bridge, connecting meso-diaminopimelic acid and D-alanine residues of adjacent peptide subunits. The ~-carboxyl group of D-glutamic acid in position two of peptide subunits was substituted with glycine amide. The teichoic acid pattern and composition differed between the strains: both contained an erythritol teichoic acid and strain C N R Z 925 also contained an N-acetylglucosaminylphosphate polymer. The erythritol teichoic acids differed in terms of the quality and quantity of substituents, but they both had N,N'-diacetyl-2,3-diamino-2,3-dideoxyglucuronic acid in common.

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