Biodegradation of Phenanthrene by Pseudomonas Bacteria Bearing Rhizospheric Plasmids in Model Plant–Microbial Associations

The consumption of phenanthrene in soil by model plant–microbial associations including natural and transconjugant plasmid-bearing rhizospheric strains of Pseudomonas fluorescens and P. aureofaciens degrading polycyclic aromatic hydrocarbons was studied. It was shown that phytoremediation of soil polluted with phenanthrene in the rhizosphere of barley (Hordeum sativum L.) was inefficient in the absence of the degrading strains. Inoculation of barley seeds with both natural and transconjugant plasmid-bearing Pseudomonas strains able to degrade polycyclic aromatic hydrocarbons (PAH) protected plants from the phytotoxic action of phenanthrene and favored its degradation in soil. Rape (Brassica napus L.) was shown to be an appropriate sentinel plant, sensitive to phenanthrene, which can be used for testing the efficiency of phenanthrene degradation in soil. Biological testing with the use of sensitive rape plants can be applied for estimation of the efficiency of phyto/bioremediation of PAH-polluted soils.     

Selection of ergot alkaloid producers by induced mutagenesis

Using the induced mutagenesis technique, A series of genetically modified Claviceps sp. VKM F-2609 strains that display high levels of agroclavine and elymoclavine synthesis were selected by induced mutagenesis. Compared to the parent strain, c106 displayed a 40-fold higher level of agroclavine synthesis, and c66 displayed an eightfold higher level of elymoclavine synthesis. The levels of synthesis of other alkaloids were decreased in these strains. The effects of various carbohydrates on the strain growth and ergot alkaloid biosynthesis was then investigated in both the parent strain and c106. The largest amount of agroclavine was synthesized by c106 strain growing on a medium with maltose.     

Factors contributing to roquefortine yield variability during cultivation of penicillium roquefortii

Variability in the roquefortine yield was shown to be associated with its consumption by the mycelium during isolation of the end product, which depended on temperature, time of culture liquid storage, and biomass concentration. This was also related to the presence in chloroform of chlorocarbonic acid ethyl ester that reacted with roquefortine.     

Optimization of the medium and cultivation conditions of Penicillium roquefortii f39 producing the diketopiperazine alkaloid roquefortine

We optimized the medium for cultivation of Penicillium roquefortii f39, a producer of roquefortine. In this medium, the roquefortine yield increased 1.5-2-fold. The increase in roquefortine content was associated with high biomass yield, but not with an increase in biosynthetic activity of the mycelium. Direct correlation was found between extracellular roquefortine concentration and amount of the inoculum. The introduction of sucrose into the growth medium allowed us to increase the concentration of roquefortine during fermentation to 90 mg/l.     

Effect of the mutation process on formation of alkaloids in Penicillium roquefortii BKM F-141 and P. fellutanum BKM F-1073

Mutant strains of Penicillium roquefortii VKM F-141 and P. Fellutanum VKM F-1073 were obtained by mutagenesis induced by ultraviolet irradiation, N-methyl-N-nitronitrosoguanidine and bromouracil. By the rates of alkaloid production, the mutant strains can be divided into three groups: 1) unable to synthesize alkaloids; 2) with a high rate of biosynthesis; 3) with changed alkaloid composition. Compounds not characteristic of wild-type cultures were found in alkaloid fractions of some mutant strains.     

Distribution of glyphosate and methylphosphonate catabolism systems in soil bacteria <Emphasis Type="Italic">Ochrobactrum anthropi</Emphasis> and <Emphasis Type="Italic">Achromobacter</Emphasis> sp

Bacterial strains capable of utilizing methylphosphonic acid (MP) or glyphosate (GP) as the sole sources of phosphorus were isolated from soils contaminated with these organophosphonates. The strains isolated from MP-contaminated soils grew on MP and failed to grow on GP. One group of the isolates from GP-contaminated soils grew only on MP, while the other one grew on MP and GP. Strains Achromobacter sp. MPS 12 (VKM B-2694), MP degraders group, and Ochrobactrum anthropi GPK 3 (VKM B-2554D), GP degraders group, demonstrated the best degradative capabilities towards MP and GP, respectively, and were studied for the distribution of their organophosphonate catabolism systems. In Achromobacter sp. MPS 12, degradation of MP was catalyzed by C–P lyase incapable of degrading GP (C–P lyase I). Adaptation to growth on GP yielded the strain Achromobacter sp. MPS 12A, which retained its ability to degrade MP via C–P lyase I and was capable of degrading GP with formation of sarcosine, thus suggesting the involvement of a GP-specific C–P lyase II. O. anthropi GPK 3 also degraded MP via C–P lyase I, but degradation of GP in it was initiated by glyphosate oxidoreductase, which was followed by product transformation via the phosphonatase pathway.     

Factors Contributing to Roquefortine Yield Variability during Cultivation of Penicillium roquefortii

Variability in the roquefortine yield was shown to be associated with its consumption by the mycelium during isolation of the end product, which depended on temperature, time of culture liquid storage, and biomass concentration. This was also related to the presence in chloroform of chlorocarbonic acid ethyl ester that reacted with roquefortine.     

New approaches to identification and activity estimation of glyphosate degradation enzymes

We propose a new set of approaches, which allow identifying the primary enzymes of glyphosate (N-phosphonomethyl-glycine) attack, measuring their activities, and quantitative analysis of glyphosate degradation in vivo and in vitro. Using the developed approach we show that glyphosate degradation can follow different pathways depending on physiological characteristics of metabolizing strains: in Ochrobactrum anthropi GPK3 the initial cleavage reaction is catalyzed by glyphosate-oxidoreductase with the formation of aminomethylphosphonic acid and glyoxylate, whereas Achromobacter sp. MPS12 utilize C-P lyase, forming sarcosine. The proposed methodology has several advantages as compared to others described in the literature.     

Physiological and biochemical characteristics of fungi of the genus Penicillium as producers of ergot alkaloids and quinocitrinins

Four cultures of fungi of the genus Penicillium belonging to Furcatum Pitt subgenus, such as P. citrinum Thom, 1910; P. corylophilum Dierckx, 1901; P. fellutanum Biourge, 1923; and P. waksmanii Zaleski, 1927, produced the ergot alkaloids, namely, agroclavine-I, and epoxyagroclavine-I; their N-N-dimers, such as dimer of epoxyagroclavine-I and the mixed dimer of epoxyagroclavine-I and agroclavine-I; and also quinoline metabolites, namely, quinocitrinin A and quinocitrinin B. Physiological and biochemical characteristics of the producers were studied. Optimal conditions for the biosynthesis of metabolome components were determined. Zinc additive to the medium stimulated the biosynthesis of the ergot alkaloids in all cases; citrinin production was increased only in P. citrinum, and that was suppressed in P. corylophinum, P. fellutanum, and P. waksmanii. This testifies that genes of the biosynthesis pathways are located in the different clusters of the producers.