Applied Biochemistry and Microbiology最新文献

Glucose–fructose syrups were studied for the first time as a carbon source for the biosynthesis of citric acid (CA) by the yeast Yarrowia lipolytica. The producer Y. lipolytica VKM Y-2373 was selected, and the growth conditions were optimized (syrup concentration, 30 g/L; pH, 6.0; aeration, 20% of saturation). The study found that the concentration of ammonium sulfate in the medium had a significant impact on CA production by Y. lipolytica. The maximum CA production was observed at a concentration of 2 g/L (NH₄)₂SO₄, while concentrations of 1.5 and 3.0 g/L resulted in a decrease of 12 and 30%, respectively. Under the selected conditions, Y. lipolytica VKM Y-2373 produced 36.7 g/L CA in a medium containing glucose–fructose syrup with 52% glucose and 57.7 g/L CA with syrup containing 92% glucose.

Proteomic analysis of the NO donor–sodium nitroprusside effect on pea seedlings roots revealed a high degree of induction of the platform propeller protein WD40, PR10, ferritin, and the chitinase-like protein. Less induction was observed for ABR17, the endochitinase-like protein, enzymes of phytoalexins synthesis, and proline iminopeptidase, which releases proline from proline-enriched proteins, and UTP-glucose-1-P-uridylyl transferase involved in the synthesis of cellulose and callose. Some of these defense compounds, such as endochitinase, chitinase-like protein, and phenolic phytoalexins, are transported into the rhizosphere and may influence the rhizosphere microbiome. There are examples of the use of NO defense properties in agrotechnology both for treating plants with NO donors and for creating stress-resistant transgenic plants with a high content of NO or compounds induced by it (ferritin, etc.).

The antagonistic activity and its features were assessed for 20 strains and isolates of entomopathogenic fungi of the genus Akanthomyces and closely related species against eight species of phytopathogenic fungi and four variants of bacteria in vitro. Isolates of the species Akanthomyces muscarius Vl 21, Vl 29, Vl 61, Vl 72, and F 14 were selected. They showed antagonism against 5–6 species of dangerous phytopathogenic fungi (in particular, causative agents of various rots and leaf spots). Their volatile organic compounds also had a pronounced fungistatic effect, and the inhibition rate reached up to 67%. These isolates are promising for use in protecting plants from a complex of fungal diseases and pests.

Peptaibols are linear or cyclic peptide antibiotics (peptabiotics) characterized by the presence of a non-proteinogenic alpha-aminoisobutyric amino acid produced by filamentous fungi from the Ascomycota phylum. They exhibit a wide range of biological activities against various microbial pathogens, protozoa, viruses, and tumor cells. In this review we described methods for the fungi cultivation, isolation, screening, purification, as well as peptaibol characterization andtheir biological activities. Currently many techniques for each step of their isolation are known, and we will focus on the most commonly used and recently developed chromatographic and spectroscopic methods for their extraction and identification.

Whole-genome sequencing was carried out, and the main characteristics of the genomes of three new strains of L. lactis AM1, MA1, and dlA, isolated from fermented milk and cereal grain products of South Africa and Russia, were established. The dual approach of in vitro and in silico analysis used in this work allowed us to assess more fully the bacteriocinogenic potential and antibiotic resistance of L. lactis strains. It was shown that L. lactis AM1 and dlA had an antagonistic effect against the test cultures of Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 6538. The growth retardation of E. coli and S. aureus after 48 hours of cocultivation was 65–75 and 30–50%, respectively. The L. lactis MA1 strain did not exhibit a significant antagonistic effect; the growth inhibition of E. coli and S. aureus was 13 and 26%, respectively. According to the results of in silico analysis using the BAGELv4.0 service, gene clusters of class IId lactococcin-like bacteriocins were found in the genomes of all three strains. In the genomes of the dlA and AM1 strains, the sactipeptide cluster, a class I bacteriocin, is additionally annotated. In silico analysis of the L. lactis genomes showed the absence of transmissible antibiotic resistance genes, and all three strains showed a phenotype susceptible to the main classes of clinically relevant antibiotics (ampicillin, streptomycin, kanamycin, gentamicin, erythromycin, clindamycin, vancomycin, tetracycline, and chloramphenicol). Taken together, the results provide valuable information about the intraspecific diversity of L. lactis and indicate the promise of using new strains as starter cultures and biopreservatives.

Lignin peroxidase (LiP9) from the basidiomycete Trametes hirsuta LE-BIN 072, an effective lignin destructor, was purified to a homogeneous state (with an RZ purity index of 1.8) and characterized for the first time. The molecular weight of LiP9 was 43 kDa and its pI was 3.2. The enzyme showed the highest activity at pH 2.5 and 35°C when veratryl alcohol was used as a substrate. The analysis of the substrate specificity showed that LiP9 oxidized phenol derivatives much faster than those of benzoic and cinnamic acids with the same substituents in the benzene ring. The highest specific activity of the enzyme was observed for catechol oxidation. The ability of LiP9 to decolorize recalcitrant dyes (reactive black 5, congo red, remazol brilliant blue R, phenol red, indigo carmine, and bromocresol green) was assessed. The highest decolorization efficiency was shown for indigo carmine (in the presence of veratryl alcohol) and bromocresol green (directly) up to 80 and 60%, respectively, in 1 hour.

Inhibition of β-lactamases involved in the development of bacterial resistance to β-lactam antibiotics is promising for restoring their effectiveness as antibacterial drugs. In this work, we screened the inhibitory activity against some serine β-lactamases of class A among humic substances of various origins, which represent complex organic matrices, as well as their narrow fractions obtained by separating preparations by acidity and polarity. The structural and group composition of broad fractions was characterized by ¹³C NMR spectroscopy; the molecular composition of narrow fractions was characterized by Fourier transform-ion cyclotron resonance mass spectrometry. The widest specificity of inhibition against various ESBL (TEM-12, TEM-17, TEM-18) and the inhibitor-resistant β-lactamase TEM-34 was possessed by the fraction of humic acids of brown coal CHA-I, isolated at pH 9: the values of residual activity of TEM -12, TEM-17, TEM-18, and TEM-34 were (%) 52 ± 5, 52 ± 5, 40 ± 4, and 58 ± 6, respectively. The data obtained for the most active narrow fraction turned out to be comparable to the effectiveness of sulfohydantoins, a promising new class of inhibitors. This indicates the feasibility of further work on the fine fractionation of natural humic substances using 2D chromatography, which will open a new, extensive source of β-lactamase inhibitors of non-β-lactam nature.

In the current work, single strand binding protein from E. coli (EcSSB) and DNA-binding protein from S. solfataricus (Sso7d) were tested to evaluate the effects on TdT activity for homopolymer substrates (T_n) that are unable to form double helix structures. We showed a significant increase in TdT activity after the addition of EcSSB even from the example of homopolymer substrates. The effects demonstrated open application of DNA binding proteins in TdT engineering and DNA-printing. The addition of EcSSB to the reaction mixture led to a significant increase in TdT activity and a shift in the reaction products towards longer oligonucleotides. The maximum effect was observed in a close-to-equimolar stoichiometric ratio (EcSSB)₄:TdT in the presence of Mn²⁺ cations. In addition, the presence of Sso7d in the reaction mixture led to a slight (up to 15%) decrease in TdT activity for substrates T₅ and T₁₅ and a more pronounced decrease for T₃₅ (up to 30%). At the same time, Co²⁺ cations reduced the inhibitory effect of Sso7d.The patterns and relationships established through our research have potential applications in various fields. Specifically, they can be utilized in protein engineering for the development of fusion proteins that are based on TdT. Furthermore, these findings can contribute to the advancement of novel enzymatic principles for de novo DNA synthesis.