Possibilities of an Electronic Nose on Piezoelectric Sensors with Polycomposite Coatings to Investigate the Microbiological Indicators of Milk.

Milk and dairy products are included in the list of the Food Security Doctrine and are of paramount importance in the diet of the human population. At the same time, the presence of many macro- and microcomponents in milk, as available sources of carbon and energy, as well as the high activity of water, cause the rapid development of native and pathogen microorganisms in it. The goal of the work was to assess the possibility of using an array of gas chemical sensors based on piezoquartz microbalances with polycomposite coatings to assess the microbiological indicators of milk quality and to compare the microflora of milk samples. Piezosensors with polycomposite coatings with high sensitivity to volatile compounds were obtained. The gas phase of raw milk was analyzed using the sensors; in parallel, the physicochemical and microbiological parameters were determined for these samples, and species identification of the microorganisms was carried out for the isolated microorganisms in milk. The most informative output data of the sensor array for the assessment of microbiological indicators were established. Regression models were constructed to predict the quantity of microorganisms in milk samples based on the informative sensors' data with an error of no more than 17%. The limit of determination of QMAFAnM in milk was 243 ± 174 CFU/cm3. Ways to improve the accuracy and specificity of the determination of microorganisms in milk samples were proposed.

Lysozyme-Sucrose Interactions in the Solid State: Glass Transition, Denaturation, and the Effect of Residual Water.

The freeze-drying of proteins, along with excipients, offers a solution for increasing the shelf-life of protein pharmaceuticals. Using differential scanning calorimetry, thermogravimetric analysis, sorption calorimetry, and synchrotron small-angle X-ray scattering (SAXS), we have characterized the properties at low (re)hydration levels of the protein lysozyme, which was freeze-dried together with the excipient sucrose. We observe that the residual moisture content in these samples increases with the addition of lysozyme. This results from an increase in equilibrium water content with lysozyme concentration at constant water activity. Furthermore, we also observed an increase in the glass transition temperature (Tg) of the mixtures with increasing lysozyme concentration. Analysis of the heat capacity step of the mixtures indicates that lysozyme does not participate in the glass transition of the sucrose matrix; as a result, the observed increase in the Tg of the mixtures is the consequence of the confinement of the amorphous sucrose domains in the interstitial space between the lysozyme molecules. Sorption calorimetry experiments demonstrate that the hydration behavior of this formulation is similar to that of the pure amorphous sucrose, while the presence of lysozyme only shifts the sucrose transitions. SAXS analysis of amorphous lysozyme-sucrose mixtures and unfolding of lysozyme in this environment show that prior to unfolding, the size and shape of lysozyme in a solid sucrose matrix are consistent with its native state in an aqueous solution. The results obtained from our study will provide a better understanding of the low hydration behavior of protein-excipient mixtures and support the improved formulation of biologics.

Magnetic Nanocomposite Materials Based on Fe3O4 Nanoparticles with Iron and Silica Glycerolates Shell: Synthesis and Characterization.

Novel magnetic nanocomposite materials based on Fe3O4 nanoparticles coated with iron and silica glycerolates (MNP@Fe(III)Glyc and MNP@Fe(III)/SiGlyc) were obtained. The synthesized nanocomposites were characterized using TEM, XRD, TGA, VMS, Mössbauer and IR spectroscopy. The amount of iron and silica glycerolates in the nanocomposites was calculated from the Mössbauer spectroscopy, ICP AES and C,H-elemental analysis. Thus, it has been shown that the distribution of Fe in the shell and core for MNP@Fe(III)Glyc and MNP@Fe(III)/SiGlyc is 27:73 and 32:68, respectively. The synthesized nanocomposites had high specific magnetization values and a high magnetic response to the alternating magnetic field. The hydrolysis of shells based on Fe(III)Glyc and Fe(III)/SiGlyc in aqueous media has been studied. It has been demonstrated that, while the iron glycerolates shell of MNP@Fe(III)Glyc is resistant to hydrolysis, the silica glycerolates shell of MNP@Fe(III)/SiGlyc is rather labile and hydrolyzed by 76.4% in 24 h at 25 °C. The synthesized materials did not show cytotoxicity in in vitro experiments (MTT-assay). The data obtained can be used in the design of materials for controlled-release drug delivery.

Hydration enthalpies of amorphous sucrose, trehalose and maltodextrins and their relationship with heat capacities.

The mechanisms of glass transitions and the behavior of small solute molecules in a glassy matrix are some of the most important topics of modern thermodynamics. Water plays an important role in the physical and chemical stability of lyophilized biologics formulations, in which glassy carbohydrates act as cryoprotectants and stabilizers. In this study, sorption calorimetry was used for simultaneous measurements of water activity and the enthalpy of water sorption by amorphous sucrose, trehalose and maltodextrins. Moreover, the heat capacity of these carbohydrates in mixtures with water was measured by DSC in a broad range of water contents. The hydration enthalpies of glassy sucrose, trehalose and maltodextrins are exothermic, and the enthalpy change of water-induced isothermal glass transitions is higher for small molecules. The partial molar enthalpy of mixing of water in slow experiments is about -18 kJ mol-1, but less exothermic in the case of small molecules at fast hydration scan rates. By measuring the heat capacities of disaccharides and maltodextrins as a function of water content, we separated the contributions of carbohydrates and water to the total heat capacities of the mixtures. The combination of these data allowed testing of thermodynamic models describing the hydration-induced glass transitions. The heat capacity changes calculated by the fitting of the hydration enthalpy data for disaccharides are in good agreement with the heat capacity data obtained by DSC, while for maltodextrins, the effect of sub-Tg transitions should be taken into account. Combining the data obtained by different techniques, we found a distinct difference in the behavior of water in glassy polymers compared to that in glassy disaccharides. By understanding the behavior of water in glassy carbohydrates, these results can be used to improve the design of freeze-dried formulations of proteins and probiotics.

Genetically encodable bioluminescent system from fungi.

Bioluminescence is found across the entire tree of life, conferring a spectacular set of visually oriented functions from attracting mates to scaring off predators. Half a dozen different luciferins, molecules that emit light when enzymatically oxidized, are known. However, just one biochemical pathway for luciferin biosynthesis has been described in full, which is found only in bacteria. Here, we report identification of the fungal luciferase and three other key enzymes that together form the biosynthetic cycle of the fungal luciferin from caffeic acid, a simple and widespread metabolite. Introduction of the identified genes into the genome of the yeast Pichia pastoris along with caffeic acid biosynthesis genes resulted in a strain that is autoluminescent in standard media. We analyzed evolution of the enzymes of the luciferin biosynthesis cycle and found that fungal bioluminescence emerged through a series of events that included two independent gene duplications. The retention of the duplicated enzymes of the luciferin pathway in nonluminescent fungi shows that the gene duplication was followed by functional sequence divergence of enzymes of at least one gene in the biosynthetic pathway and suggests that the evolution of fungal bioluminescence proceeded through several closely related stepping stone nonluminescent biochemical reactions with adaptive roles. The availability of a complete eukaryotic luciferin biosynthesis pathway provides several applications in biomedicine and bioengineering.

Synthesis of Boronated Amidines by Addition of Amines to Nitrilium Derivative of Cobalt Bis(Dicarbollide).

A series of novel cobalt bis(dicarbollide) based amidines were synthesized by the nucleophilic addition of primary and secondary amines to highly activated B-N+≡C-R triple bond of the propionitrilium derivative [8-EtC≡N-3,3'-Co(1,2-C2B9H10)(1',2'-C2B9H11)]. The reactions with primary amines result in the formation of mixtures of E and Z isomers of amidines, whereas the reactions with secondary amines lead selectively to the E-isomers. The crystal molecular structures of E-[8-EtC(NMe2)=HN-3,3'-Co(1,2-C2B9H10)(1',2'-C2B9H11)], E-[8-EtC(NEt2)=HN-3,3'-Co(1,2- C2B9H10)(1',2'-C2B9H11)] and E-[8-EtC(NC5H10)=HN-3,3'-Co(1,2-C2B9H10)(1',2'-C2B9H11)] were determined by single crystal X-ray diffraction.

Hydration-Induced Structural Changes in the Solid State of Protein: A SAXS/WAXS Study on Lysozyme.

The stability of biologically produced pharmaceuticals is the limiting factor to various applications, which can be improved by formulation in solid-state forms, mostly via lyophilization. Knowledge about the protein structure at the molecular level in the solid state and its transition upon rehydration is however scarce, and yet it most likely affects the physical and chemical stability of the biological drug. In this work, synchrotron small- and wide-angle X-ray scattering (SWAXS) are used to characterize the structure of a model protein, lysozyme, in the solid state and its structural transition upon rehydration to the liquid state. The results show that the protein undergoes distortion upon drying to adopt structures that can continuously fill the space to remove the protein-air interface that may be formed upon dehydration. Above a hydration threshold of 35 wt %, the native structure of the protein is recovered. The evolution of SWAXS peaks as a function of water content in a broad range of concentrations is discussed in relation to the structural changes in the protein. The findings presented here can be used for the design and optimization of solid-state formulations of proteins with improved stability.

Controller protein of restriction-modification system Kpn2I affects transcription of its gene by acting as a transcription elongation roadblock.

C-proteins control restriction-modification (R-M) systems' genes transcription to ensure sufficient levels of restriction endonuclease to allow protection from foreign DNA while avoiding its modification by excess methyltransferase. Here, we characterize transcription regulation in C-protein dependent R-M system Kpn2I. The Kpn2I restriction endonuclease gene is transcribed from a constitutive, weak promoter, which, atypically, is C-protein independent. Kpn2I C-protein (C.Kpn2I) binds upstream of the strong methyltransferase gene promoter and inhibits it, likely by preventing the interaction of the RNA polymerase sigma subunit with the -35 consensus element. Diminished transcription from the methyltransferase promoter increases transcription from overlapping divergent C-protein gene promoters. All known C-proteins affect transcription initiation from R-M genes promoters. Uniquely, the C.Kpn2I binding site is located within the coding region of its gene. C.Kpn2I acts as a roadblock stalling elongating RNA polymerase and decreasing production of full-length C.Kpn2I mRNA. Mathematical modeling shows that this unusual mode of regulation leads to the same dynamics of accumulation of R-M gene transcripts as observed in systems where C-proteins act at transcription initiation stage only. Bioinformatics analyses suggest that transcription regulation through binding of C.Kpn2I-like proteins within the coding regions of their genes may be widespread.

Temporal dynamics of methyltransferase and restriction endonuclease accumulation in individual cells after introducing a restriction-modification system.

Type II restriction-modification (R-M) systems encode a restriction endonuclease that cleaves DNA at specific sites, and a methyltransferase that modifies same sites protecting them from restriction endonuclease cleavage. Type II R-M systems benefit bacteria by protecting them from bacteriophages. Many type II R-M systems are plasmid-based and thus capable of horizontal transfer. Upon the entry of such plasmids into a naïve host with unmodified genomic recognition sites, methyltransferase should be synthesized first and given sufficient time to methylate recognition sites in the bacterial genome before the toxic restriction endonuclease activity appears. Here, we directly demonstrate a delay in restriction endonuclease synthesis after transformation of Escherichia coli cells with a plasmid carrying the Esp1396I type II R-M system, using single-cell microscopy. We further demonstrate that before the appearance of the Esp1396I restriction endonuclease the intracellular concentration of Esp1396I methyltransferase undergoes a sharp peak, which should allow rapid methylation of host genome recognition sites. A mathematical model that satisfactorily describes the observed dynamics of both Esp1396I enzymes is presented. The results reported here were obtained using a functional Esp1396I type II R-M system encoding both enzymes fused to fluorescent proteins. Similar approaches should be applicable to the studies of other R-M systems at single-cell level.

Evaluation of a 27-gene inherited cancer panel across 630 consecutive patients referred for testing in a clinical diagnostic laboratory.

BACKGROUND: Extensive clinical and genetic heterogeneity of inherited cancers has allowed multi-gene panel testing to become an efficient means for identification of patients with an inherited predisposition to a broad spectrum of syndromic and nonsyndromic forms of cancer. This study reports our experience with a 27-gene inherited cancer panel on a cohort of 630 consecutive individuals referred for testing at our laboratory with the following objectives: 1. Determine the rates for positive cases and those with variants of uncertain clinical significance (VUS) relative to data published in the recent literature, 2. Examine heterogeneity among the constituent genes on the panel, and 3. Review test uptake in the cohort relative to other reports describing outcomes for expanded panel testing. METHODS: Clinical and genomic data were reviewed on 630 individuals tested on a panel of 27 genes selected on the basis of high (≥ 40%) or moderate to low (≤ 40%) lifetime risk of hereditary cancer. These patients were not enriched for adherence to the National Comprehensive Cancer Network (NCCN) criteria for Hereditary Breast and Ovarian Cancer (HBOC) or Lynch Syndrome (LS) and constitute a referral laboratory cohort. RESULTS: Sixty-five individuals with variants classified as pathogenic or likely pathogenic across 14 genes were identified for an overall positive rate of 10.3%. Although a family history of cancer constituted a major reason for referral, accounting for 84% of our cohort, excluding patients with a known familial variant did not have a significant impact on the observed positive rate (9% vs 10.3%). More than half (58%) of the pathogenic or likely pathogenic variants were observed in high or moderate to low risk genes on the panel, while only 42% occurred in classic HBOC or LS-associated genes. CONCLUSION: These results provide the actual percentage of family or personal history of cancer that can be attributed to pathogenic or likely pathogenic variants in one or more of the genes on our panel and corroborate the utility of multi-gene panels over sequential testing to identify individuals with an inherited predisposition to cancer.

Exploring the landscape of pathogenic genetic variation in the ExAC population database: insights of relevance to variant classification.

PURPOSE: We evaluated the Exome Aggregation Consortium (ExAC) database as a control cohort to classify variants across a diverse set of genes spanning dominant and recessively inherited disorders. METHODS: The frequency of pathogenic variants in ExAC was compared with the estimated maximal pathogenic allele frequency (MPAF), based on the disease prevalence, penetrance, inheritance, allelic and locus heterogeneity of each gene. Additionally, the observed carrier frequency and the ethnicity-specific variant distribution were compared between ExAC and the published literature. RESULTS: The carrier frequency and ethnic distribution of pathogenic variants in ExAC were concordant with reported estimates. Of 871 pathogenic/likely pathogenic variants across 19 genes, only 3 exceeded the estimated MPAF. Eighty-four percent of variants with ExAC frequencies above the estimated MPAF were classified as "benign." Additionally, 20% of the cardiac and 19% of the Lynch syndrome gene variants originally classified as "VUS" occurred with ExAC frequencies above the estimated MPAF, making these suitable for reassessment. CONCLUSIONS: The ExAC database is a useful source for variant classification and is not overrepresented for pathogenic variants in the genes evaluated. However, the mutational spectrum, pseudogenes, genetic heterogeneity, and paucity of literature should be considered in deriving meaningful classifications using ExAC.Genet Med 18 8, 850-854.

Age-related decrease in TCR repertoire diversity measured with deep and normalized sequence profiling.

The decrease of TCR diversity with aging has never been studied by direct methods. In this study, we combined high-throughput Illumina sequencing with unique cDNA molecular identifier technology to achieve deep and precisely normalized profiling of TCR ß repertoires in 39 healthy donors aged 6-90 y. We demonstrate that TCR ß diversity per 10(6) T cells decreases roughly linearly with age, with significant reduction already apparent by age 40. The percentage of naive T cells showed a strong correlation with measured TCR diversity and decreased linearly up to age 70. Remarkably, the oldest group (average age 82 y) was characterized by a higher percentage of naive CD4(+) T cells, lower abundance of expanded clones, and increased TCR diversity compared with the previous age group (average age 62 y), suggesting the influence of age selection and association of these three related parameters with longevity. Interestingly, cross-analysis of individual TCR ß repertoires revealed a set >10,000 of the most representative public TCR ß clonotypes, whose abundance among the top 100,000 clones correlated with TCR diversity and decreased with aging.

Live-Cell STED Microscopy with Genetically Encoded Biosensor.

Of the various super-resolution techniques, stimulated emission depletion (STED) microscopy achieves the best temporal resolution at high spatial resolution, enabling live-cell imaging beyond the diffraction limit. However, STED and most other super-resolution imaging methods utilize a particular type of information extractable from the raw data, namely the positions of fluorophores. To expand on the use of super-resolution techniques, we report here the live-cell STED microscopy of a dynamic biosensor. Using the fluorescent H2O2 sensor HyPer2 for subdiffraction imaging, we were able not only to image filaments with superior resolution by localizing emission but also to trace H2O2 produced within living cell by monitoring brightness of the probe. STED microscopy of HyPer2 demonstrates potential utility of FP-based biosensors for super-resolution experiments in situ and in vivo.

Disordered mesoporous silica particles: an emerging platform to deliver proteins to the lungs.

Pulmonary delivery and formulation of biologics are among the more complex and growing scientific topics in drug delivery. We herein developed a dry powder formulation using disordered mesoporous silica particles (MSP) as the sole excipient and lysozyme, the most abundant antimicrobial proteins in the airways, as model protein. The MSP had the optimal size for lung deposition (2.43 ± 0.13 µm). A maximum lysozyme loading capacity (0.35 mg/mg) was achieved in 150 mM PBS, which was seven times greater than that in water. After washing and freeze-drying, we obtained a dry powder consisting of spherical, non-aggregated particles, free from residual buffer, or unabsorbed lysozyme. The presence of lysozyme was confirmed by TGA and FT-IR, while N2 adsorption/desorption and SAXS analysis indicate that the protein is confined within the internal mesoporous structure. The dry powder exhibited excellent aerodynamic performance (fine particle fraction <5 µm of 70.32%). Lysozyme was released in simulated lung fluid in a sustained kinetics and maintaining high enzymatic activity (71-91%), whereas LYS-MSP were shown to degrade into aggregated nanoparticulate microstructures, reaching almost complete dissolution (93%) within 24 h. MSPs were nontoxic to in vitro lung epithelium. The study demonstrates disordered MSP as viable carriers to successfully deliver protein to the lungs, with high deposition and retained activity.

Charge-compensated nido-carborane derivatives in the synthesis of iron(II) bis(dicarbollide) complexes.

A series of stable iron(II) bis(dicarbollide) derivatives [8,8'-(RNHC(Et)HN)2-3,3'-Fe(1,2-C2B9H10)2] (R = Pr, R = Ph, (CH2)2OH, (CH2)3OH, (CH2)2NMe2) was prepared starting from FeCl2 or [FeCl2(dppe)] and the corresponding nido-carboranyl amidines [10-RNHC(Et)HN-7,8-C2B9H11]. In a similar way, the reactions of the oxonium derivatives of nido-carborane with FeCl2 in tetrahydrofuran in the presence of t-BuOK lead to the corresponding stable oxonium derivatives iron(II) bis(dicarbollide) [8,8'-(RR'O)2-3,3'-Fe(1,2-C2B9H10)2] (RR' = (CH2)4, (CH2)2O(CH2)2, (CH2)5; R = R' = Et), which can be alternatively prepared by the reaction of the parent iron(II) bis(dicarbollide) with tetrahydrofuran or 1,4-dioxane in the presence of Me2SO4. The cyclic voltammetry studies of the synthesized iron(II) bis(dicarbollide) derivatives revealed that the introduction of amidinium and oxonium substituents leads to a significant increase in the Fe2+/Fe3+ redox potential relative to the parent iron(II) bis(dicarbollide). The redox potentials of the oxonium derivatives are close to the redox potential of ferrocene and somewhat lower than redox potentials of sulfonium and phosphonium derivatives of iron(II) bis(dicarbollide).

Iron(III) Monoglycerolate as a New Biocompatible Precursor in the Synthesis of Bioactive Nanocomposite Glycerohydrogels.

BACKGROUND: Nanocomposite glycerohydrogels based on biocompatible elementcontaining glycerolates are of practicular interest for biomedical applications. OBJECTIVE: Using two biocompatible precursors, silicon and iron glycerolates, a new bioactive nanocomposite silicon‒iron glycerolates hydrogel was obtained by sol-gel method. METHODS: The composition and structural features of the hydrogel were studied using a complex of modern analytical techniques, including TEM, XRD, and AES. On the example of experimental animals hemostatic activity of the hydrogel was studied, as well as primary toxicological studies were carried out. RESULTS: The composition of dispersed phase and dispersion medium of silicon‒iron glycerolates hydrogel was determined. The structural features of hydrogel were revealed and its structure model was proposed. It was shown that silcon-iron glycerolates hydrogel is nontoxic, and exhibits pronounced hemostatic activity. CONCLUSION: Silicon-iron glycerolates hydrogel is a potential hemostatic agent for topical application in medical and veterinary practice.

Regulation of gene expression in restriction-modification system Eco29kI.

The Eco29kI restriction-modification (R-M) system consists of two partially overlapping genes, eco29kIR, encoding a restriction endonuclease and eco29kIM, encoding methyltransferase. The two genes are thought to form an operon with the eco29kIR gene preceding the eco29kIM gene. Such an organization is expected to complicate establishment of plasmids containing this R-M system in naive hosts, since common logic dictates that methyltransferase should be synthesized first to protect the DNA from cleavage by the endonuclease. Here, we characterize the Eco29kI gene transcription. We show that a separate promoter located within the eco29kIR gene is sufficient to synthesize enough methyltransferase to completely modify host DNA. We further show that transcription from two intragenic antisense promoters strongly decreases the levels of eco29kIR gene transcripts. The antisense transcripts act by preventing translation initiation from the bicistronic eco29kIR-eco29kIM mRNA and causing its degradation. Both eco29kIM and antisense promoters are necessary for Eco29kI genes establishment and/or stable maintenance, indicating that they jointly contribute to coordinated expression of Eco29kI genes.

Sucrose, Lactose, Thermogravimetry, and Differential Thermal Analysis: The Estimation of the Moisture Bond Types in Lactose-Containing Ingredients for Confectionery Products with Reduced Glycemic Index.

This research is aimed at conducting a comparative analysis of the dehydration process of lactose-containing ingredients and sucrose. Differential scanning calorimetry (DSC) and thermogravimetry (TG) methods were used to investigate the moisture bond types and the process of thermal degradation in native whey, dried skimmed milk, dried whole milk, dried milk whey demineralized, purified lactose, and sucrose. There were several peaks on the DSC and TG curves for lactose-containing ingredients. They determine the loss of the physically absorbed water on surfaces, physically occluded water and hydrate-forming water (up to 180°C), anomerization of lactose (160-220°C), and melting followed by decomposition (above 230°C). The multiple peaks on the dDSC curves from 135 to 170°C indicate the course of the Maillard reaction in the mix with proteins. For the native whey, the amount of chemically bound water was 56.11 ± 1%; for the dried whole milk, it was 59.86 ± 1%; for the milk whey demineralized, it was 64.56 ± 1%; and for the dried skimmed milk, it was67.17 ± 1%. The results are presented as mean values ± SD (n = 3) and were considered statistically significant when P < 0.05. The similar to some extent form of the DSC and TG curves to lactose-containing ingredients and granulated sugar confirms the possibility of using them as the component of bakery and confectionery product formulas to reduce the glycemic index and improve organoleptic properties of products as well as correct their mineral compositions. Considering the constant changing of technologies for obtaining various dairy ingredients as well as the occurrence of their new kinds, such studies contribute to the expansion of existing knowledge and reference data.

Diversity of Arbuscular Mycorrhizal Fungi in Distinct Ecosystems of the North Caucasus, a Temperate Biodiversity Hotspot.

BACKGROUND: Investigations that are focused on arbuscular mycorrhizal fungus (AMF) biodiversity is still limited. The analysis of the AMF taxa in the North Caucasus, a temperate biodiversity hotspot, used to be limited to the genus level. This study aimed to define the AMF biodiversity at the species level in the North Caucasus biotopes. METHODS: The molecular genetic identification of fungi was carried out with ITS1 and ITS2 regions as barcodes via sequencing using Illumina MiSeq, the analysis of phylogenetic trees for individual genera, and searches for operational taxonomic units (OTUs) with identification at the species level. Sequences from MaarjAM and NCBI GenBank were used as references. RESULTS: We analyzed >10 million reads in soil samples for three biotopes to estimate fungal biodiversity. Briefly, 50 AMF species belonging to 20 genera were registered. The total number of the AM fungus OTUs for the "Subalpine Meadow" biotope was 171/131, that for "Forest" was 117/60, and that for "River Valley" was 296/221 based on ITS1/ITS2 data. The total number of the AM fungus species (except for virtual taxa) for the "Subalpine Meadow" biotope was 24/19, that for "Forest" was 22/13, and that for "River Valley" was 28/24 based on ITS1/ITS2 data. Greater AMF diversity, as well as number of OTUs and species, in comparison with that of forest biotopes, characterized valley biotopes (disturbed ecosystems; grasslands). The correlation coefficient between "Percentage of annual plants" and "Glomeromycota total reads" r = 0.76 and 0.81 for ITS1 and ITS2, respectively, and the correlation coefficient between "Percentage of annual plants" and "OTUs number (for total species)" was r = 0.67 and 0.77 for ITS1 and ITS2, respectively. CONCLUSION: High AMF biodiversity for the river valley can be associated with a higher percentage of annual plants in these biotopes and the active development of restorative successional processes.

The Effects of Rhizophagus irregularis Inoculation on Transcriptome of Medicago lupulina Leaves at Early Vegetative and Flowering Stages of Plant Development.

The study is aimed at revealing the effects of Rhizophagus irregularis inoculation on the transcriptome of Medicago lupulina leaves at the early (second leaf formation) and later (flowering) stages of plant development. A pot experiment was conducted under conditions of low phosphorus (P) level in the substrate. M. lupulina plants were characterized by high mycorrhizal growth response and mycorrhization parameters. Library sequencing was performed on the Illumina HiseqXTen platform. Significant changes in the expression of 4863 (padj < 0.01) genes from 34049 functionally annotated genes were shown by Massive Analysis of cDNA Ends (MACE-Seq). GO enrichment analysis using the Kolmogorov-Smirnov test was performed, and 244 functional GO groups were identified, including genes contributing to the development of effective AM symbiosis. The Mercator online tool was used to assign functional classes of differentially expressed genes (DEGs). The early stage was characterized by the presence of six functional classes that included only upregulated GO groups, such as genes of carbohydrate metabolism, cellular respiration, nutrient uptake, photosynthesis, protein biosynthesis, and solute transport. At the later stage (flowering), the number of stimulated GO groups was reduced to photosynthesis and protein biosynthesis. All DEGs of the GO:0016036 group were downregulated because AM plants had higher resistance to phosphate starvation. For the first time, the upregulation of genes encoding thioredoxin in AM plant leaves was shown. It was supposed to reduce ROS level and thus, consequently, enhance the mechanisms of antioxidant protection in M. lupulina plants under conditions of low phosphorus level. Taken together, the obtained results indicate genes that are the most important for the effective symbiosis with M. lupulina and might be engaged in other plant species.