FMN-reductase from Escherichia coli and its effect on the activity of luciferase from marine bacterium Vibrio fischeri]

Interactions of luciferases isolated from Vibrio fischeri 6 and Escherichia coli JM109(pF3) (bearing cloned V. fischeri luxAB genes) with FMN reductase isolated from E. coli JM109 were studied. FMN reductase formed a stable complex with luciferase, suggesting similar properties of the FMN reductases in the taxonomically close families Vibrionaceae and Enterobacteriaceae.     

Sequencing and comparative analysis of the lux operon of Photorhabdus luminescens strain ZM1: ERIC elements as putative recombination spots

The EcoRI chromosomal fragment (6782 bp) containing the lux operon of Photorhabdus luminescens was cloned in pUC18 and completely sequenced. Enteric repetitive intergenic consensus (ERIC), an imperfect palindrome (125-127 bp) characteristics for Enterobacteriaceae genomes, was found in three sites. Strain Zm1 proved to differ in ERIC number and location from strains Hb, Hm, and Hw. Nucleotide substitution analysis showed that luxC and luxB, which are more than 1 kb away from ERIC, are similar to the corresponding Hb genes, whereas luxD, luxA, and luxE, which are close to ERIC, are intermediate between their Hb and Hw counterparts. The Hb/Hw nucleotide substitution ratio was 1:1 in regions adjacent to ERIC. Hence ERIC were assumed to play a role of recombination hot spots in the bacterial genome.     

Sequencing and Comparative Analysis of the lux Operon of Photorhabdus luminescens Strain Zm1: ERIC Elements as Putative Recombination Hot Spots

The EcoRI chromosomal fragment (6782 bp) containing the lux operon of Photorhabdus luminescens was cloned in pUC18 and completely sequenced. Enteric repetitive intergenic consensus (ERIC), an imperfect palindrome (125–127 bp) characteristic of Enterobacteriaceae genomes, was found in three sites. Strain Zm1 proved to differ in the ERIC number and location from strains Hb, Hm, and Hw. Nucleotide substitution analysis showed that luxC and luxB, which are more than 1 kb away from ERIC, are similar to the corresponding Hb genes, whereas luxD, luxA, and luxE, which are close to ERIC, are intermediate between their Hb and Hw counterparts. The Hb/Hw nucleotide substitution ratio was 1:1 in regions adjacent to ERIC. Hence ERIC can be thought to be recombination hot spots in the bacterial genome.     

Effect of low intensity electromagnetic radiation on the toxicity of domestic wastewater tested with the “Ecolum” test-system

Irradiation of wastewater by low intensity electromagnetic radiation (ν = 42.25 GHz) affects the integral toxicity of water of a different purification degree, which was revealed by an express method on the basis of the Ecolum-08 bacterial luminescent test system. We have shown that the lower the degree of water purification, the higher the toxicity effect of EMR. This allows us to propose the Ecolum bacterial luminescent test system for the primary testing of the effect of EMR.     

Evaluation of the properties of potassium ferrate used for water purification by luminescence bioassay

Characteristics of four natural water samples from urban and rural areas and the efficiency of a new purifying agent, potassium ferrate K₂FeO₄, were studied by bacterial luminescence bioassay for 30 minutes. It was revealed that two samples of water from the urban areas are toxic, while the other two samples (one from urban and one from rural environment) are nontoxic. Numerous data obtained on the increase in toxicity index with time allow reasonable conclusions to be made about the chemical nature of substances present in the test water samples. Toxic natural water samples were likely to contain heavy metals and were well purified using potassium ferrate, including via their adsorption. In nontoxic natural water samples, toxic complexes with organic compounds present in water could form at the addition of potassium ferrate. The obtained data call for further studying the properties of potassium ferrate complexes with organic compounds. Bacterial luminescence bioassay is a promising method for the rapid assessment of properties of various water sources (their integral toxicity and presumable chemical composition) and new reagents for their purification (effective concentrations, bactericidal properties, and mechanisms of interacting with heavy metals and organic substances in water).     

Lipid and gramicidin C biosynthesis in Bacillus brevis during stab cultivation

The content of lipids was studied in the gramicidin producing variants of Bacillus brevis var. G.-B. in the process of submerged cultivation. The greatest accumulation of lipids preceded the highest content of gramicidin C in the producing cells. The interrelation between the synthesis of lipids and that of gramicidin C is discussed.     

Chemical composition of polysaccharides of the red alga <Emphasis Type="Italic">Tichocarpus crinitus</Emphasis> (Tichocarpaseae) from different sites of Peter the Great Bay,Sea of Japan

A comparative analysis of the quantitative and qualitative composition of polysaccharides in the red seaweed Tichocarpus crinitus, collected at different sites of Peter the Great Bay in the Japanese Sea (Sivuch’ya Bay, Risovaya Bay and Sobol’ Bay) was carried out. The sites differed in their biotopic and anthropogenic characteristics. The main monosaccharides of the investigated algal polysaccharides were galactose and 3.6-anhydrogalactose, which are structural components of carrageenan The highest contents of protein and glucose were found in the KCl-soluble fraction of algae from Sobol Bay that were experiencing increased anthropogenic pressure. Fourier transform infrared spectroscopy revealed that the KCl-insoluble polysaccharide fractions of all investigated algae had an identical structure corresponding to κ/β-carrageenan, while the KCl-soluble polysaccharide fractions had differences in their structures. The content of heavy metals and micro- and macroelements in polysaccharide fractions differed among algae growing in areas with different biotopic and anthropogenic conditions.