Applied Biochemistry and Microbiology

Erratum to: Purification and Characterization of β-Glucosidase Produced by Trichoderma Citrinoviride Cultivated on Microalga Chlorella Vulgaris The article is published in the original.

Biotransformation of Glycoginsenosides to Intermediate Products and Aglycones using a Hemicellulosome Produced by Cellulosimicrobium cellulan Abstract Ginsenosides Rb1, Rb2 and Re were converted into corresponding intermediates and aglycones using a multienzyme complex produced by Cellulosimicrobium cellulans F16. The whole conversion processes were monitored at different time points by UPLC-PDA-MS. The hydrolysates and the conversion routes were identified using standard samples and electrospray ionization MS. Ginsenosides Rb1, Rb2, and Re were finally converted to the product protopanaxadiol and ginsenoside Rg2. The results indicated that the multienzyme complex Xyl I produced by C. cellulans F16 can be an efficient tool for the transformation of ginsenosides.

Enantiospecific Sorption of L-Lysin by Molecularly Imprinted Sorbents Based on Methacrylic Acid and Ethylene Glycol Dimethacrylate Abstract L-lysine-imprinted polymeric sorbents based on methacrylic acid and ethylene glycol dimethacrylate have been synthesized. The equilibrium and kinetics of amino acid sorption on the synthesized sorbents and control sorbent (a nonimprinted analog) are compared. It is shown that the enantioselective separation of the D,L-lysine racemic mixture was most effectively performed on polymeric sorbent synthesized in the presence of 6 mol % L-lysine. The amino acid was fixed on the surface layer of this sorbent at energy-equivalent, specific binding sites.

Design and Characterization of a Methionineless Variant of Thermostable Chaperon GroEL from Thermus thermophilus Abstract The GroEL chaperon is of significant interest due to its structure and function, which evolved to facilitate protein folding, and its potential application in artificial expression systems to obtain soluble recombinant proteins. A GroEL variant derived from Thermus thermophilus in which all methionine residues were substituted for leucine was created. This modified chaperon was purified to homogeneity. GroEL completely retained its quaternary structure of the original chaperon (double heptamer), together with its thermostable properties. Both the structure of the new chaperon and its usage as a carrier to obtain target recombinant proteins are attractive for researchers in the field. Also, the substitution of methionine residues in a carrier protein substantially simplifies target protein purification.

Antimicrobial Peptides Produced by Alkaliphilic Fungi Emericellopsis alkalina : Biosynthesis and Biological Activity Against Pathogenic Multidrug-Resistant Fungi Abstract The ability of 22 strains of the Emericellopsis alkalina species to synthesize the antimicrobial peptaiboles A118-35, A118-36, and A118-37 with antifungal activity was studied. The ability to synthesize peptaibols is typical for 72% of the studied strains of the species. It was established that peptaibol production is a strain-specific feature and depends on the cultivation conditions and the concentration of sugars and carbon sources. The isolated peptaibol A118-37 was active against opportunistic Candida albicans yeast and Apergillus niger mold fungus, as well as against clinical fungal isolates of mycosis pathogens with multiple resistance.

Conversion of 4-Chlorophenoxyacetic Acid by the Pseudomonas sp. 36DCP Strain Abstract The new natural 36DCP strain, which is capable of using 4-chlorophenoxyacetic acid (4-CPA) as the sole source of carbon and energy, was characterized. A culture isolated from a soil sample contaminated with chemical waste was identified according to physiological, biochemical, cultural, morphological features and analysis of the 16S rRNA gene sequence as a strain belonging to the Pseudomonas genus. In the batch culture, Pseudomonas sp. 36DCP degraded 45% of 4-CPA from the initial concentration after 5 days of incubation. Based on the identified intermediate metabolites in the culture medium (para-benzoquinone and hydroquinone), it was found that the conversion of 4-CPA in Pseudomonas sp. 36DCP proceeds through the hydroquinone pathway. This degradation pathway of monochlorinated phenoxyacetic acids has not previously been described in bacteria.

Influence of Resveratrol and Dihydroquercetin on Physiological and Biochemical Parameters of the Poly-Extremophilic Yeast Yarrowia lipolytica under Temperature Stress Abstract First, the effects of the biologically active polyphenols resveratrol and dihydroquercetin (DHQ) on morpho-physiological parameters and the antioxidant status of polyextremophilic yeast Yarrowia lipolytica at optimal and elevated temperatures were studied. Cultivation in the presence of 30 μM resveratrol at the optimal temperature caused a twofold increase in superoxide dismutase activity. It was shown that cultivation at a high temperature and high DHQ concentration stimulated a decrease in the alternate respiration level. High resveratrol concentrations and low dihydroquercetin concentrations were shown to have an inhibitory effect on the survival rate of Y. lipolytica yeast cells, while no visible inhibition effect of yeast growth was recorded at the optimal growth temperature. Polyphenols were shown to have a moderate stimulatory effect on the oxygen absorption rate by yeast cells.

Inhibition of Autoxidation of Paprika Carotenoids by Plant Antioxidants Abstract— The antioxidant properties of essential oils, spice extracts, ionol, ascorbyl palmitate, and their mixtures were evaluated according to the effectiveness of their inhibition of autoxidation of carotenoids in paprika extract. The degree of carotenoid oxidation was determined by spectrophotometry. The activities of coriander, and garlic essential oils, and red pepper extract were almost identical; oregano essential oil and rosemary extract had higher inhibitory activities, and the maximum activity was found in clove oil, ionol, and ascorbyl palmitate. The efficiency of the inhibition of carotenoid autoxidation decreased by 4–10% with a decrease in the concentration of all antioxidants from 4 to 1% by the carotenoid weight. Rosemary extract inhibited autoxidation in proportion to the concentration, while the degree of inhibition was 67% at a content of 4% and 29% at 2%. The composition was found to have a complex effect on the effectiveness of inhibition for antioxidant mixtures. Therefore, in mixtures containing clove essential oil, the total activity remained close to the activity of this essential oil. Rosemary extract reduced the activity of clove oil in a 1 : 1 mixture by 18% but did not affect the activity of oregano essential oil, ascorbyl palmitate, or ionol. No pronounced additive or synergistic effects were observed in any antioxidant mixtures.

Mediator BOD Biosensor Based on Cells of Microorganisms Isolated from Activated Sludge Abstract Three bacterial strains (SPB1, SPB2, and SPB3) isolated from the activated sludge of treatment facilities most efficiently oxidized (as compared to other strains) a model solution based on glucose and glutamic acid in the presence of a ferrocene mediator. The possible use of isolated strains as a basis for a mediator-type amperometric BOD biosensor was studied. Analysis of 16S rRNA genes demonstrated that the SPB1, SPB2, and SPB3 strains are 99.79–100% similar to the Paracoccus yeei BAA-599T, Pseudomonas veronii DSM 11331T, and Bacillus proteolyticus TD42T strains, respectively. It was established that the bioreceptor element based on the P. yeei SPB1 strain possessed the best characteristics. It was stable in storage at 4°С for 22 days, and the lower limit of detectable concentrations was 1.3 mg О2/dm3. In order to search for the most efficient electron transfer mediator for this strain, nine compounds, including ferrocene, thionine, methylene blue, potassium hexacyanoferrate(III), and 2,6-dichlorophenolindophenol, were screened. The mediator electron transfer signals were obtained for each of them. Ferrocene was the most efficient in terms of sensitivity and the amount of substrate oxidation that can be registered in the presence of the mediator. An analysis of ten samples of wastewater (before and after purification) and the rivers of Tula oblast demonstrated that the use of ferrocene and P. yeei SPB1 strain cells made it possible to obtain data with a high correlation (R = 0.9934) with the results of the standard method.

Binding of Erythrocyte Hemoglobin to the Membrane to Realize Signal-Regulatory Function (Review) Abstract Reversible protein binding with membrane components and the cytoskeleton is one of mechanisms of cell metabolism control. This is a crucial mechanism for the regulation of metabolism in nuclear-free cells, mammal erythrocytes, in which it is realized via hemoglobin modification to the membrane-bound state. Hemoglobin can interact with the membrane in different ligands and redox statuses. Thus, this protein can function as a sensor of redox and oxygen conditions. Depending on the oxygen conditions, deoxyHb changes the energetic metabolism, morphology, and deformability of erytrocytes, as well as the release of vascular tone regulators, NO and ATP. This is fulfilled via interaction with the main integral protein of erythrocyte membrane, the band 3 protein. The products of hemoglobin oxidative denaturation, irreversible hemichromes, also carry out a signaling function. Accumulating over time or as result of oxidative stress, chemichromes contain information on the redox conditions and the longevity of erythrocyte functioning. It has been hypothesized that erythrocytes have a program that initiates intracellular hemolysis. The participation of hemoglobin and its membrane-bound form (MBHb) in the realization of this program is discussed. The role of NO donors in the regulation of erythrocyte stability is debated as well. The use of data on the MBHb content in erythrocytes is proposed for clinical diagnostics.