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The influence of the Cu(II)-complexes of thiophene oligomers synthesized by oxidative polymerization of thiophene with Cu2+ ions in ZSM-5 zeolite channels on fungicidal and antimicrobial properties was studied. It has been found that the heterogeneous system culture medium-modified zeolite increases sporulation of the tested fungus (Aspergillus niger) and concurrently kills yeast (Candida albicans). These effects are attributed to a slow release of Cu2+ ions and thiophene oligomers into the culture medium. As for the tested bacteria (G+ Staphylococcus aureus, G- Escherichia coli), the percentage of the killed cells increases due to light activation of the system. The light effect is assigned to photogeneration of the reactive oxygen species (ROS), mainly *OH radicals, which were registered in the water solution by EPR spectroscopy. It has been confirmed that the thiophene oligomers present in the Cu-ZSM-5 microstructure slow down the release of copper into the medium.

The effect of 18 compounds of the aryloxyaminopropanol type--potential beta-adrenolytics (differing each from other by modifications in the hydrophilic and lipophilic part of the molecule) on the inhibition of oxygen evolution rate in spinach chloroplasts has been investigated. The compounds with n-octyloxymethyl and n-nonyloxymethyl group in position 3 of aromatic ring were found to exhibit the highest inhibitory activity (IC50 = 67, resp. 120 mumol dm-3). The compounds containing a heterocycle or the dimethylamino group in the hydrophilic part of the molecule and with propoxymethyl group on the aromatic ring were not active. Using EPR spectroscopy it was found that the studied compounds interact with Z+/D+ intermediates, i.e. tyrosine radicals TyrZ and TyrD situated in D1 and D2 proteins on the donor side of photosystem 2. Higher concentrations of the studied inhibitors cause release of Mn2+ ions from the oxygen evolving complex which is situated in photosystem 2. The interaction of the tested compounds with chlorophyll occurring in the photosynthetic centres has been confirmed by fluorescence measurements as well.

The effects of piperidinopropylesters of 2-, 3- and 4-alkoxy substituted phenylcarbamic acids (PPACs) on oxygen evolution rate (OER) in spinach chloroplasts were investigated. PPAGs show concentration-dependent effects, namely OER inhibition at higher effector concentrations and OER stimulation at lower concentrations, i.e. below the inhibitory concentration range. The inhibitory efficiency of PPACs showed dependence on the alkyl chain length of the alkoxy substituent as well as on the position of this substituent on the benzene ring. Using EPR spectroscopy and fluorescence measurements it was confirmed that the site of PPAC inhibitory action is the donor side of photosystem 2, where D1 and D2 proteins are situated, namely the intermediates Z+/Y+, and the manganese cluster containing protein as well. The stimulating effects of PPACs on OER in spinach chloroplasts at relatively low effector concentrations are caused by photophosphorylation uncoupling due to protonophore properties of the effectors.

A simple method is presented for the determination of partition coefficient of an effector between water environment and biological material, based on concentration-dependent effects. The method allows the determination of partition coefficients for biological objects such as algae, bacteria and other microorganisms.

The inhibitory effect of 14 aqua(aryloxyacetato) copper(II) complexes on oxygen evolution rate in spinach chloroplasts has been investigated. The inhibitory effect of these effectors on photosynthesis was confirmed by Hill reaction as well as by EPR and fluorescence spectroscopies. The results of the EPR study showed that the sites of action of the studied effectors are Z+ and Y+ intermediates at the donor side of the photosystem (PS) 2. The EPR study also showed that another site of action is the oxygen evolving complex, namely its manganese cluster. The above suggestions were supported by the results of the fluorescence study as well. Based on the restoring of the photosynthetic electron transport to 2,6-dichlorophenol-indophenol in chloroplasts inhibited by the studied Cu(II) complexes using sym-diphenylcarbazide it can be assumed that the own core of PS2 (P680) and a part of the electron transport chain-at least up to plastoquinone-remain intact.

Using the model compound trimecaine, it was found that algicidal effects exhibited by the local anaesthetics of the acetanilide type were caused by two different mechanisms. The first inhibitory mechanism occurring at low concentrations of the anaesthetic is connected with the uncoupling of the photophosphorylations in algal chloroplasts and is accompanied by the enhancement of the oxygen evolving rate in algal photosynthesis. The second mechanism of inhibition of the photosynthesis in algae, taking place at higher concentrations of the anaesthetic, is connected with the damaging of the manganese containing protein on the donor side of photosystem 2 and is accompanied by a decrease of the oxygen evolving rate in algal photosynthesis.

2-Alkylthio-6-aminobenzothiazoles and their 6-N-substituted derivatives 3-(2-alkylthio-6-benzothiazolylaminomethyl)-2-benzothiazolineth iones and 3-(2-alkylthio-6-benzothiazolylaminomethyl)-6-bromo-2-benzothia zolinones inhibit photosynthetic processes in spinach chloroplasts and the chlorophyll production in Chlorella vulgaris. The inhibitory activity depends on the alkyl chain length of the thioalkyl substituent. The site of action of the effectors studied is on the donor side of photosystem 2 before the site of action of diphenylcarbazide. The highest antialgal effects were exhibited by compounds containing bromine.

The inhibitory activity of 22 substituted aryloxyaminopropanols having beta-lytic and local anaesthetic properties was studied from the view-point of their influences on photosynthesis in plant chloroplasts as well as growth and synthesis of chlorophyll in algae and wheat plants. The inhibitory activity increased significantly with the increasing length of alkyl-substituents of the aryloxyaminopropanol molecule. Less pronounced dependences were found with respect to the position of the substituent chain on benzene ring. The inhibitory activity was found to correlate well with the lipophilicity of the compounds studied.

Electron spin resonance spectroscopy (ESR) was used to study the effects of amphiphilic amines of the carbamate, amide, and ester type and amine oxide on the photosynthetic system of spinach chloroplasts. The ESR signal II connected to the photosynthetic center PS II donor side was observed to diminish in the presence of amines, whereas that of PS I remained unchanged. The inhibition of PS II increased with the increasing of amine concentration. In the presence of amines, the light: dark chloroplast ESR signals ratio as well as the intensity of the ESR signal of unbound Mn2+ increased. It is suggested that the amphiphilic amines affect the structure of PS II and the electron transfer to PS I. The effects of the amines tested on the photosynthetic system correlate with their potency to perturb the lipid membrane structure.

The antimicrobial activity of the homologous series of N,N-dimethylalkylamine oxides (DMAO) was found to be quasi parabolically dependent on alkyl chain length with a maximum at n approximately 15 and n approximately 12 for Staphylococcus aureus and Escherichia coli, respectively. The physiochemical properties of DMAOs as characterized by critical micelle concentrations, retention times of 1-alkenes generated from DMAOs by gas-liquid chromatography, Rm values in reversed phase chromatography, and bacterial lipid/aqueous phase partition coefficients were found to correlate with the alkyl chain length. The effect of DMAOs on the structure of the model membrane prepared from isolated lipids from Escherichia coli as detected by a spin probe method was maximal for the alkyl chain length n approximately 10-12 coinciding with the maximum in the antimicrobial activity observed with Escherichia coli. It is suggested that the cut-off in the DMAO antimicrobial activity is caused by the cut-off in the DMAO perturbing effect on the membrane structure.

Interaction of bactericidal surfactants N-(1-methyldodecyl)-N, N, N-trimethylammonium bromide (2-ATDBr) and N-(1-methyldodecyl)-N, N-dimethylamine oxide (2-ATDNO) with phospholipid membranes prepared from Escherichia coli -- isolated lipids was studied by ESR spectroscopy using m-doxyl stearic acid (m-DSA, m = 5, 12, 16) and N-cetyl-N, N-dimethyl-N-tempoylammonium bromide spin labels located in different membrane depths. 2-ATDBr was found to be a more potent membrane perturbant than 2-ATDNO both at equal membrane and sample concentrations; this is in compliance with the respective antimicrobial activities of these agents. Using the statistical model of hydrocarbon chains in lipid bilayers, the probabilities of the formation of gauche conformations and the effective energy differences between the trans and gauche conformations were calculated from m-DSA order parameters for two different bilayer regions. Based on these parameters, a molecular model of the location of surfactant molecules in bilayer has been formulated. It has been suggested that at low concentrations the surfactant molecules are located in structural defects between lipid clusters in the bilayer. After filling up these defects, the surfactant molecules penetrate into the clusters between lipid molecules, expand the bilayer laterally and increase the amount of gauche conformations in the hydrocarbon chains in the hydrophobic core of the bilayer.