Identification and determination of the intra- and extracellular aminopeptidase activity by synthetic L-Ala-, L-Tyr-, and L-Phe-beta-napthylamide.

A simple, rapid and straightforward procedure for identification and determination of intracellular and extracellular activity of aminopeptidases employing synthetic substrates beta-naphtylamides of L-Ala, L-Phe, and L-Tyr was used. Poppy cells (Papaver somniferum L.) permeabilized by Tween 80 were immobilized via crosslinking by glutaraldehyde. Glutaraldehyde immobilized poppy cells lost their viability and demonstrated significantly lower aminopeptidase activities than untreated control cells probably due to a damage to the enzyme active centre. Poppy cells immobilized by pectate and alginate have retained high activity of studied aminopeptidases. The culture medium (without cells) used for the identification and determination of extracellular enzyme activities retained 20-21%, whereas intracellular activities were estimated to be 79-80% of total enzyme activity. Thus the intracellular specific activity was 1.00-1.07 higher.

Benzalkonium chloride (BAC) and dimethyldioctadecyl-ammonium bromide (DDAB), two common quaternary ammonium compounds, cause genotoxic effects in mammalian and plant cells at environmentally relevant concentrations.

Quaternary ammonium compounds (QACs) are cationic surfactants that are widely used as disinfectants. In the present study, we tested two important representatives, namely, benzalkonium chloride (BAC) and dimethyldioctadecyl-ammonium bromide (DDAB) in four genotoxicity tests, namely, in the Salmonella/microsome assay with strains TA 98, TA 100 and TA 102, in the single-cell gel electrophoresis (SCGE) assay with primary rat hepatocytes and in micronucleus (MN) assays with peripheral human lymphocytes and with root tip cells of Vicia faba. In the bacterial experiments, consistently negative results were obtained in the dose range between 0.001 and 110 microg per plate in the presence and absence of metabolic activation while significant induction of DNA migration was detected in the liver cells. With BAC, a moderate but significant effect was found with an exposure concentration of 1.0 mg/l while DDAB caused damage at lower doses (0.3 mg/l). The effects were not altered when the nuclei were treated with formamidopyridine glycosylase, indicating that they are not due to formation of oxidized purines. The MN assays with blood cells were carried out under identical conditions to the SCGE experiments and a significant increase was seen at the highest dose levels (BAC: 1.0 and 3.0 mg/l; DDAB: 1 mg/l). Both compounds also caused significant induction of MN as well as inhibition of cell division in plant cells, the lowest effective levels were 1.0 and 10 mg/l for DDAB and BAC, respectively. Our findings show that both chemicals induce moderate but significant genotoxic effects in eukaryotic cells at concentrations which are found in wastewaters and indicate that their release into the environment may cause genetic damage in exposed organisms. Furthermore, the direct contact of humans to QAC-containing detergents and pharmaceuticals that contain substantially higher concentrations than those which were required to cause effects in eukaryotic cells in the present study should be studied further in regard to potential DNA-damaging effects in man.

Identification and determination of invertase secreted by tomato cells.

A simple and rapid procedure for the identification and determination of extracellular invertase from a culture medium of tomato cell suspension cultures is described. Sucrose was used as substrate for the determination of the extracellular and intracellular activities of the enzyme. The culture medium (without cells) was used for identification and determination of extracellular enzyme activity. Intracellular activity was estimated from the cell suspension.

A simple method for the identification and assay of extracellular plant beta-galactosidase.

A simple, rapid and reproducible procedure for the identification of extracellular Californian poppy (Eschscholzia californica Cham.) beta-galactosidase is described using callus cultures of seedlings from the tested plant, roots of 4-days-old seedlings of Californian poppy germinating on agar plates and cell suspension cultures cultivated from callus cultures. 6-Bromo-2-naphthyl-beta-D-galactopyranoside and p-nitrophenyl-beta-D-galactopyranoside were used as substrates for the determination of the intracellular and extracellular activities of beta-galactosidase. The extracellular beta-galactosidase activity was identified by evaluating the dye-zones in an agar medium. The enzyme from Californian poppy callus cultures or from seedling roots cultivated on agar plates supplemented with 6-bromo-2-naphthyl-galactopyranoside hydrolyzed this substrate releasing 6-bromo-2-naphthol. By simultaneous coupling with hexazonium p-rosaniline the corresponding (reddish-brown) azo-dye was formed. The agar plate method described permits rapid, simple and specific detection of plant producers of extracellular beta-galactosidase.

[Detection of secretion of beta-galactosidase by plant cells]. / Prezentácia sekrécie beta-galaktozidázy rastlinnými bunkami.

A simple, sensitive and reproducible method of detection of extracellular beta-galactosidase was worked out. beta-Galactosidase secreted by the callus culture, or the roots of sprouting plants, hydrolyzes the substrate (6-bromo-2-naphthyl-beta-D-galactopyranoside) to produce beta-D-galactose and 6-bromo-2-naphthol, which after simultaneous azocoupling with hexazotized p-rosaniline, or basic fuchsine, produce a reddish brown compound, nearly insoluble in water (a diazonium salt). The colouring under the callus culture and around it, as well as the colouring of the roots of the sprouting plants, is a manifestation of the activity of extracellular beta-galactosidase by the objects under study. The intensity of the colouring is a measure of their enzymatic activity. The share of intracellularly localized enzyme represents the majority and the share of extracellular beta-galactosidase the minority.

Retrospective biomonitoring: a hundred years of environmental pollution at selected areas in Slovakia.

Tetrade analyses of Calluna vulgaris from herbarium specimens showed significant differences in the frequency of aborted pollen tetrads over the last 100 years within various parts of Slovakia. Specifically, we observed changes in the dynamics of pollution peaking in the year 1965 in heavily polluted industrial area of an aluminium factory in Ziar nad Hronom.

Beta-galactosidase in immobilized cells of gherkin Cucumis sativus L.

Cell suspensions of gherkin (Cucumis sativus L.) were permeabilized by Tween-80, and immobilized by glutaraldehyde. Beta-galactosidase showed pH optimum at 4.9 and temperature optimum at 58 degrees C. The enzyme catalysed hydrolysis was linear for 3 h with 60-68% conversion of the substrate. The cells characterized by high beta-galactosidase activity and stability on long-term storage showed valuable technological properties.