The numerous pyoverdines so far characterized as siderophores of fluorescent Pseudomonas could be usually differentiated one from each others by the two physico-chemical and physiological methods of siderotyping, i.e., siderophore-isoelectrofocusing and siderophore-mediated iron uptake. As shown in the present paper, the structural diversity of the peptide chain characterizing these molecules results in a very large panel of molecular masses representing 64 different values ranging from 889 to 1,764 Da for the 68 compounds included in the study, with only a few structurally different compounds presenting an identical molecular mass. Thus, the molecular mass determination of pyoverdines through mass spectrometry could be used as a powerful siderotyping method.

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Heavy metals are the major pollutants of the coastal waters of Primorye. This is associated with the natural geochemical features of the region, as well as with significant anthropogenic inputs. It is known that microorganisms are resistant actually to all heavy metals [15,20,24]. They are capable of rapid adaptation to specific habitat conditions and can thus provide an indicator of environmental changes [2,11,19]. The diversity of individual bacterial responses to toxic effects supports the plasticity of communities and, in some cases, ensures the possibility of melioration of the environment [12,15]. However, it has been experimentally demonstrated that in the marine environment bacterial adaptation to pollution, including heavy metals, can be accompanied by processes hazardous to human and animals [5]. Within the microbiocenoses of polluted waters, plasmid-bearing genes of biodegradation and resistance to toxicants are becoming increasingly more frequent. These genes may be linked with genes of antibiotic resistance and genes responsible for pathogenic properties [13,23]. Thus, individual bacterial strains have developed the capability of surviving under toxicological stress and dominate microbiocenoses. This is essential to the study of metal resistant microbiocenoses, which are being formed in response to selective anthropogenic pressure.This work is focused on study of the diversity and heavy metal resistance of bacterial strains isolated from coastal waters of Primorye with different extents and natures of heavy metal pollution, identification of highly resistant strains, and analysis of the range of their antibacterial resistance and plasmid number and size. MATERIALS AND METHODSTwo hundred twenty bacterial strains were aseptically isolated from the water or from the thallus of brown algae collected from several locations in Primorye: Rudnaya Bay (northern Primorye), which is situated in the area of mining and processing of complex ores; a reference station located far from pollution sources; and Zolotoi Rog Bay, which receives combined anthropogenic and technogenic inputs. Pure cultures of bacteria were isolated from selective metalcontaining media [4] according to the standard method [8]. The formula of the basic medium was as follows (g/liter): peptone, 5.0; yeast extract, 5.0; glucose, 1.0; K 2 HPO 4 , 0.2, MgSO 4 , 1.0; CaCO 3 , 1.0, distilled water, 500 ml, sea water, 500 ml; pH, 7.8. To it were added chlorides of Cd, Cu, Zn, Ni, and Co or nitrate of Pb. The individual metal resistance of bacterial strains was assessed by determining the minimum inhibitory concentration (MIC) of the salt of each metal [18]. Pure cultures were inoculated (in three replicates) by the imprint method in the above medium supplemented with metal salts in increasing concentrations.The morphological, cultural, and biochemical properties of bacterial strains were tested using widely adopted methods [8]. Bacteria were identified according to Berge's manual [9] and using standard tests API-20E and API-20NE (BioMerieux, France...