R. % - proponion of resistant strains of microorganisi 

 100 - 



AmpicitlfitAmp) 

 Genlamvcin fGeni 

 Kunttmycin iKanf 

 Slrepu>m\cin fSlr) 



AmpitillintAmp) 

 Genfamycin (Gent 

 Karuinyctn (Kant 

 Slrepiomycin iSlr) 



BenzilpeniiHlintBfn) 



MeuaUin tMii) 

 Monomycin iMon) 



Fig. I . Resistance of marine microorganisms to antibiotics. 



Thirty-three strains of Pseiidomonades, 1 7 strains of other 

 bacillary bacteria (including 7 strains from the group 

 Flavobacterium-Cytophaga. 5 from the ^Qnu^Arthrohacter, 2 

 from the genus Bacillus), and 12 strains of coccal forms 

 (including 8 strains from the genus Siaphylococcus, 2 from the 

 genus PUmococcus, and 2 from the genus Micrococcus) were 

 studied for resistance to heavy metals. Results show that 

 strains from the Chukchi Sea respond to heavy metals as those 

 from the Baltic Sea; that is. a wide MIC range and high modal 

 MIC values were found. 



These results suggest that bacteria from the Chukchi Sea 

 have adapted to high concentrations of heavy metals. Because 

 all groups of bacteria did not differ in the mode and MIC range 

 of cadmium and lead, natural stability of the strains is one 

 explanation. However, modal values for Co, Cu, Hg. and. 

 partially. Ni. are substantially lower in Chukchi Sea strains 

 relative to those from the Baltic Sea. For instance, the mode of 

 cobalt MIC was 1.024 mg/1 for Chukchi Sea strains and 

 128 mg/1 for Baltic strains, while that for Cu was 256 and 

 128 mg/l and Hg was 32 and 16 mg/1. respectively. 



However, for Chukchi Sea strains, the lower and upper values 

 of the MIC range were somewhat lower for most metals. 

 Although specific strains from the Chukchi Sea are resistant to 

 heavy metals, their resistance was considerably lower than in 

 strains from the Baltic Sea. 



Anthropogenic pollution of marine waters with chemical 

 substances produces a considerable negative effect on the 

 genetic apparatus of microbes. This effect is due to mutagenic 

 and genotoxic material of certain pollutants. Microorganisms 

 are not only targets for the genotoxicants or mutagenes, but in 

 some cases they themselves enhance the effect and strengthen 

 it. Thus, microorganisms can, in the process of decomposition, 

 activate transforming pollutants into more toxic forms. 

 Similarly, it is acknowledged that microorganisms produce 

 different biologically active substances that elicit a broad 

 antibiotic effect. The chemical composition and structure of 

 these compounds suggest that they can also possess mutagenic 

 and genotoxic effects and, under environmental pressures, the 

 mutagenic and genotoxic activity of microorganisms themselves 

 can be strengthened. Thus, the development of marine 

 microorganisms, conditioned by chemical pollution, can serve 

 as an extra factor that strengthens the mutagenic stress upon 

 microbial communities. If ecological conditions continue to 

 deteriorate as in some regions of the World Ocean, the frequency 

 of induced mutations may increase, resulting in an artificial 

 evolution of bacterial strains. 



The problem of mutagenic, genotoxic, and carcinogenic 

 effect of marine pollution, and the role of the microorganisms 

 are not yet investigated. 



To detect genotoxic and DNA-damaging effects of 

 chemical compounds, bacteria that are most sensitive are 

 widely used. The disturbance of bacteria genotype is 

 immediately expressed in its phenotype because of the gaploid 

 chromosomes. In addition, a high level of correlation is 

 observed between mutagenic activity found in microorganisms 

 and their carcinogenic properties in animals. 



Therefore, three strains of Escherichia coli were used for 

 the genetic screening: E. coli WP-2, E. coli Rec-, and E. coli 

 Pol A-. Sixty-two strains of bacteria capable of decomposing 

 hydrocarbons and cyclic organic compounds of the Bering Sea 

 were studied. This work involved: I. heat-killed marine 

 bacteria; 2. exometabolites — metabolic products released by 

 bacteria into the culture medium; and J. endometabolites — 

 metabolites contained in bacterial cells and released by 

 ultrasound disintegration. 



The investigations showed that the ability to synthesize 

 metabolites with general toxic activity and DNA-damaging 

 effect was common to the different taxonomic groups of 

 Pseudomonas. Bacterium. Alcaligenes. Planococcus. 

 Flavobacterium-Cytophaga. Xantomonas, Arthrobacter. and 

 Bacillus. The general toxic effect of Pseudomonades was 

 noted for exo- and endometabolites and killed cells at 75, 50, 

 and eO'/f of the 32 strains, respectively (Table 9). The DNA- 

 damaging effect was found in 83% of all Bering Sea strains. 

 The results suggest that the genotoxic effect of the genus 

 Pseudomonas is not a specific feature of this genus. On E. coli 

 Pol A- model this effect was typical of exometabolites found in 

 69% of the strains, endometabolites in 54% of the strains, heat- 



107 



