Alfalfa (Medicago sativa L.) suspension cultures respond to yeast elicitors with a strong alkalinization of the culture medium, a transient synthesis of activated oxygen species, and typical late defence reactions such as phytoalexin accumulation and increased peroxidase activity. The alkalinization reaction as well as the oxidative burst were also observed when tobacco (Nicotiana tabacum L. ) cell-suspension cultures were treated with yeast elicitors. Depending on the degree of polymerization, N-acetyl chitin oligomers induced the alkalinization response in both plant cell-suspension cultures, while only tobacco cell cultures developed an oxidative burst. Suspension-cultured tobacco cells responded to Sinorhizobium meliloti nodulation factors with a maximal alkalinization of 0.25 pH units and a remarkable oxidative burst. In contrast, addition of Sinorhizobium meliloti nodulation factors to suspension-cultured alfalfa cells induced a slight acidification of the culture medium, instead of an alkalinization, but no oxidative burst.

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Three methods were used to determine the normal ranges for cholesterol and triglyceride in serum of 385 blood donors (289 men, 96 women, aged 18-50 years). Enzymatically determined cholesterol levels had an upper normal range to 6.73-6.99 mmol/l (2.6-2.7 g/l), i.e. lower than with the colorimetric method. The upper range for the triglycerides was 2.28-2.85 mmol/l (2.0-2.5 g/l). Both variables were age and sex-dependent. It is suggested that in assessing lipid levels they should be divided into normal, border-line and definitely abnormal values.

Lipooligosaccharides, synthesized by soil bacteria of the genera Rhizobium, are known to have multifunctional effects on a wide variety of plants as signal substances in symbiosis initiation, cell response elicitation and growth regulation. These so called nodulation (Nod-) factors represent interesting biotechnological products with respect to fundamental studies of symbiotic interactions as well as for potential applications. Therefore, a batch fermentation process on a scale of 30 l has been developed by means of the Rhizobium meliloti strain R.m. 1021 (pEK327) strongly overexpressing the genes for the synthesis of Nod factors. Induction by the flavone luteolin led to growth associated production of the lipooligosaccharides. Ultrafiltration was used for separating the biomass from the filtrate containing the extracellular Nod factors. Simultaneously, ultrafiltration reduced the amount of lipophilic substances, which would otherwise interfere with processes downstream. The second separation step consisted in adsorption on XAD-2, a nonspecific hydrophobic adsorptive resin. Adsorption of Nod factors was carried out by batch operation of a stirred tank. Desorption was performed by elution with methanol in a fixed bed column. A semi-preparative reversed phase HPLC (Polygoprep 100-30 C18) was chosen as the final purification step. The Nod factors were obtained after evaporation and lyophilization. Thus, about 600 mg of Nod factors were produced from 20 l of fermentation broth. The Nod factors produced by Rhizobium meliloti R.m. 1021 (pEK327) were identified by liquid secondary ion mass spectrometry and by reversed-phase HPLC as fluorescent derivatives of 2-aminobenzamide. The biological activity of the products was demonstrated by means of the root hair deformation (HAD-) assay.

for the simultaneous determination of copper and iron in serumIn most laboratories, copper and iron are determined in serum by a manual photometric method. Since the clinical laboratory is often asked for both of these parameters together, the present work describes the simultaneous measurement of copper and iron in one sample with a standard 2-channel Auto-Analyser. This procedure has the following advantages over the manual method: simple operation with reagents that can be prepared in the laboratory; 30-35 analyses per hour; the use of dialysis results in low interference by haemolytic, icteric or lipaemic sera; avoidance of crude errors that may result from contaminated pipettes, centrifuge tubes, test tubes and cuvettes. The suitability of the method was tested thoroughly for a period of six months. The method is highly specific and the sensitivity is adequate. The determination of copper gave a repeatability of 2.8% (var. coeff.) and a recovery of 99.7%. The precision was 5-6% for copper and 9-10% for iron, while the measured values of both parameters varied by only 1-2% from the true values of a control serum. The method is therefore unreservedly recommended for use in the clinical chemical laboratory.