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The purpose of this work was to assess the suitability of solid and liquid waste generated during processing of the vegetative part of poplar as substrates for biochemical processing in order to obtain biologics for various purposes. For the study, we used post-extraction residues, as well as a cubic liquid formed after distilling essential oils and extracting alcohol-soluble substances from the vegetative part of the balsamic poplar (Populus balzamifera L.). Siberian strains of fungi of the genus Trichoderma used as a biodestructor. Studies have shown that the vegetative part of poplar and its individual elements are an available substrate for the growth of mycelial fungi. The high yield of spores (4.5×109 spor/g) and the formation of humic substances (11%) used as plant growth stimulators during solid-phase cultivation of the MG-97 strain of Trichoderma fungi gives grounds to use the vegetative part of poplar as a technological raw material for obtaining a biological product of the "Trichodermin" type or soil humification. Depending on the purpose of the preparations, the duration of cultivation can vary: for obtaining agricultural biologics up to 15 days, more – for soil humification. The inclusion of a cubic liquid at the stage of substrate humidification allows to obtain a biological product with a higher spore titer (5×109 spor/g), makes it possible to close the water consumption cycle and make the technology of processing the vegetative part of poplar waste-free.

The vegetative part of coniferous and deciduous wood plants is a unique source of natural compounds. The natural renewability of woody plants makes them an inexhaustible raw material for the production of biologically active substances. In the process of their production, about 70% of the non-recyclable post-extraction residue of the vegetative part remains, which is used as a feed additive. Since many plant wastes have a low protein content, in which essential amino acids are most often the limiting ones, they must be enriched with microbial protein, in particular the protein of basidial fungi. For this purpose, the fungi Fomitopsis pinicola (sw.) P. KARST (Fp5-15) were used in this work, since they are the least demanding to plant substrates and have high growth indicators. The purpose of this study was to study the amino acid composition of products obtained as a result of bioconversion of post-extraction residues of fir tree greens and the vegetative part of balsamic poplar (buds, litter). The analysis of the amino acid composition of the products showed that the protein score increases during the biodegradation process (phenylalanine and tyrosine-by 35 %, threonine – by 37.5%). Also, high amounts of glycine, alanine, histidine, aspartic acid, and glutamic acid were found in the products of biodegradation. In terms of the content of a number of amino acids, the resulting products are superior to cereals and feed products based on the vegetative part of woody plants. Thus, the results obtained show the possibility of using fermentation products as protein feed additives.

The article presents the results of a study of the impact of the enzyme complex strains M99-9 and K6-15 micro-peach fungi of the genus Trichoderma on a mixed substrate. It is established that in the process of biodegradation with strains K6-15 M99-9 in the substrate reduced content of extractives 2.1-2.4 times that of the polysaccharide is 1.5-1.8 times, and ligninase substances 1.2-1.4 times. This was an accumulation of up to 9-12% of humic substances. The decrease in the mass of the substrate during the cultivation of the strain M99-9 was 17.3%, and the strain K6 – 15-30% less. The most productive on this substrate is strain K6-15. The growth of conidia within two weeks of cultivation for strain K6-15 was 16.6·108 CFU/g and strain M99-9 – 11,5·108 CFU/g. High yield of spores and formation of humic substances during cultivation of fungi of the genus Trichoderma makes it possible to use the vegetative part of a poplar as raw materials for receiving a biological product “Trichodermin” or humification of the soil

Objective: to analyze the parameters of 2D and 3D transthoracic echocardiography (TEE) with speckle-tracking technology in young athletes. Materials and methods: 79 athletes (52 male, 27 female, median age 20,5±3,7 years) undergone prospective analysis. Participants were divided into groups by level of training (group A-professionals and group B-amateurs) and by gender (group 1-men and group 2-women). Athletes underwent 12-lead ECG, 2D TTE and 3D TTE with a speckle-tracking. The evaluation of LV function was performed using the speckle-tracking method with the assessment of LV longitudinal strain in the Automated Function Imaging mode. Results: significant differences in LDV (р

The effectiveness of forest resources depends on the comprehensiveness and rationality of their consumption and processing into finished products. This article discusses the problem of using solid fir wood greenery residues generated during the industrial production of essential oils. Bioconversion is considered to be the most promising use. The objective of this research was to study the chemical composition of bioconversion products of fir wood greenery-based substrates. The РР-3.2 strain of Pleurotus pulmonarius (Fr.) Quél was used as a biodestructor. In the process of bioconversion, the contents of polysaccharides and lignin substances is reduced to 38% and 28%, respectively. Up to 20% of protein accumulates in bioconversion products of fir wood greenery. The amount of nucleic acids is not more than 1.5 g per kg, the contents of heavy metals, such as mercury, cadmium, arsenic, and lead, do not exceed the maximum permissible concentration standards. The substrate weight loss reaches 15%. When fallen leaves and post-extraction poplar bud residues are added to the substrate, the substrate-destroying activity of fungi increases, and the protein content increases by 3%. The digestibility of products as a result of bioconversion increases 1.6–2.8 times depending on the substrate composition. The obtained data support the recommendation of post-fermented substrates based on fir wood greenery and balsam poplar biomass for use as a protein feed additive.

The effectiveness of forest resources depends on the comprehensiveness and rationality of their consumption and processing into finished products. This article discusses a problem of utilising solid fir wood greenery residues generated during the industrial production of essential oils. Bioconversion is considered to be the most promising utilization method. The objective of this research was to study the chemical composition of bioconversion products of fir wood greenery-based substrates. The РР-3.2 strain of Pleurotus pulmonarius (Fr.) Quél was used as a biodestructor. In the process of bioconversion, the contents of polysaccharides and lignin substances is reduced to 38 and 28 % respectively. Up to 20 % of protein accumulates in bioconversion products of fir wood greenery. The amount of nucleic acids is not more than 1.5 g per 1 kg, the contents of heavy metals, such as mercury, cadmium, arsenic, lead, do not exceed maximum permissible concentration standards. The substrate weight loss reaches 15 %. When fallen leaves and post-extraction poplar bud residues are added to the substrate, the substrate-destroying activity of fungi rises, as well as the protein content increases by 3 %. The digestibility of products as a result of bioconversion increases 1.6–2.8 times depending on the substrate composition. The obtained data enable to recommend post-fermented substrates based on fir wood greenery and balsam poplar biomass for use as a protein feed additive.

Background Cognitive processing speed is important for performing everyday activities in persons with mild cognitive impairment (MCI). However, its role in daily function has not been examined while simultaneously accounting for contributions of Alzheimer’s disease (AD) risk biomarkers. We examine the relationships of processing speed and genetic and neuroimaging biomarkers to composites of daily function, mobility, and driving. Method We used baseline data from 103 participants on the MCI/mild dementia spectrum from the Applying Programs to Preserve Skills trial. Linear regression models examined relationships of processing speed, structural magnetic resonance imaging (MRI), and genetic risk alleles for AD to composites of performance-based instrumental activities of daily living (IADLs), community mobility, and on-road driving evaluations. Results In multivariable models, processing speed and the brain MRI neurodegeneration biomarker Spatial Pattern of Abnormality for Recognition of Early Alzheimer’s disease (SPARE-AD) were significantly associated with functional and mobility composite performance. Better processing speed and younger age were associated with on-road driving ratings. Genetic risk markers, left hippocampal atrophy, and white matter lesion volumes were not significant correlates of these abilities. Processing speed had a strong positive association with IADL function (p < .001), mobility (p < .001), and driving (p = .002). Conclusions Cognitive processing speed is strongly and consistently associated with critical daily functions in persons with MCI in models including genetic and neuroimaging biomarkers of AD risk. SPARE-AD scores also significantly correlate with IADL performance and mobility. Results highlight the central role of processing speed in everyday task performance among persons with MCI/mild dementia.

The authors examine historical experience of application of standard designs in buildings. The relevance of the research topic is determined by the established and announced by the state goals of expansion of the use of model projects. These objectives are to accelerate the development and reduce the cost of the project documentation for the construction, improving its quality, the use of standardized technical and technological solutions and reducing the estimated cost of capital construction. The paper presents the current system of regulatory legal acts in the field of design in the construction of the model. The analysis of the main requirements to include information in the register of model project documentation, model project passport is presented. The authors view the prospects of development of model project system to meet the challenges associated with an acute social challenge - the resettlement of citizens from emergency and dilapidated housing.

Objectives Enamel organ epithelium (EOE) gives rise to the major epithelial-derived cell types of tooth including the ameloblasts. The formation of enamel, termed amelogenesis, occurs through the cytodifferentiation of ameloblasts, ultimately leading to apoptosis and necrosis of these cells with eruption. Therefore, studies regarding enamel matrix formation and bioengineering have been limited. In this study, we establish and characterize two mouse immortalized ameloblast-like cell lines using human papillomavirus 16 (HPV16) E6/E7 oncogenes for the first time. Setting and sample population Two mouse EOE dental cell lines (EOE-2M and EOE-3M). Material and methods Isolated EOE primary cells were used to establish clonal cell lines and immortalized using the HPV16 E6/E7 gene platform. Two established cell lines were characterized by growth rate (Cell Proliferation Assay, MTS), gene (quantitative RT-PCR) and protein (immunocytochemistry) expression profiles, and mineralization potential (in situ alkaline phosphatase (ALP) histochemistry and Xylene Orange staining) in media supplemented with ascorbic acid and β-glycerophosphate. Gene and protein expression analyses included specific enamel matrix and ameloblast cell markers: Amel, Ambn, Enam, Amtn, ODAM, MMP20, Krt14 and DLX3. Results Both cell lines were maintained in excess of 30 passages, with EOE-3M cells proliferating at a slightly higher rate. The cell lines expressed all tested enamel matrix markers and produced a mineralized ECM demonstrating an ameloblast-like profile. Conclusions Two mouse ameloblasts-like immortalized cell lines have been characterized that will be useful tool for studies regarding enamel bioengineering.

Overexpression of transforming growth factor-β1 (TGF-β1) has been shown to lead to mineralization defects in both the enamel and dentin layers of teeth. A TGFB1 point mutation (H222D), derived from published cases of Camurati–Engelmann disease (CED), has been shown to constitutively activate TGF-β1, leading to excess bone matrix production. Although CED has been well documented in clinical case reports, there are no published studies on the effect of CED on the dentition. The objective of this study was to determine the dental manifestations of hyperactivated TGF-β1 signaling using an established mouse model of CED-derived TGF-β1 mutation. Murine dental tissues were studied via radiography, micro-CT, immunohistochemistry, and qRT-PCR. Results showed that initial decreased dental mineralized tissue density is resolved. Proliferation assays of incisor pulp and alveolar bone cell cultures revealed that cells from transgenic animals displayed a reduced rate of growth compared to alveolar bone cultures from wild-type mice. TGF-β family gene expression analysis indicated significant fold changes in the expression of Alpl, Bmp2–5, Col-1, -2, -4, and -6, Fgf, Mmp, Runx2, Tgfb3, Tfgbr3, and Vdr genes. Assessment of SIBLINGs revealed downregulation of Ibsp, Dmp1, Dspp, Mepe, and Spp1, as well as reduced staining for BMP-2 and VDR in mesenchymal-derived pulp tissue in CED animals. Treatment of dental pulp cells with recombinant human TGF-β1 resulted in increased SIBLING gene expression. Conclusions: Our results provide in vivo evidence suggesting that TFG-β1 mediates expression of important dentin extracellular matrix components secreted by dental pulp, and when unbalanced, may contribute to abnormal dentin disorders. J. Cell. Physiol. 231: 1106–1113, 2016. © 2015 Wiley Periodicals, Inc.

Every year the number of free land plots for construction of buildings is steadily decreasing in cities. In this regard, the participants in the investment and construction process are increasingly seeking to maximize the use of land. A logical way for this is to use high-rise construction. However, until recently, builders encountered serious obstacles in the form of lack of special norms and rules for the design of high-rise buildings. It led to the need for individual coordination of each high-rise facility, the development and approval of special technical conditions, the passage of numerous administrative approvals. Thus, investment activity regarding the construction of high-rise buildings in the Russian Federation is reduced. In 2016, there were regulatory changes that substantially alleviated these difficulties. In this article, the authors analyze the features of the town-planning normative-legal field of high-rise construction and its development, track the interrelations between the regulatory regulation of the construction of similar facilities, with the real need, the technical feasibility and economic feasibility of their construction in the urban district of Samara. Conclusions and suggestions are also based on the analysis of the norms of urban zoning, the residential real estate market and the value of land plots.

Singleton-Merten syndrome (SMS) is an infrequently described autosomal-dominant disorder characterized by early and extreme aortic and valvular calcification, dental anomalies (early-onset periodontitis and root resorption), osteopenia, and acro-osteolysis. To determine the molecular etiology of this disease, we performed whole-exome sequencing and targeted Sanger sequencing. We identified a common missense mutation, c.2465G>A (p.Arg822Gln), in interferon induced with helicase C domain 1 (IFIH1, encoding melanoma differentiation-associated protein 5 [MDA5]) in four SMS subjects from two families and a simplex case. IFIH1 has been linked to a number of autoimmune disorders, including Aicardi-Goutières syndrome. Immunohistochemistry demonstrated the localization of MDA5 in all affected target tissues. In vitro functional analysis revealed that the IFIH1 c.2465G>A mutation enhanced MDA5 function in interferon beta induction. Interferon signature genes were upregulated in SMS individuals’ blood and dental cells. Our data identify a gain-of-function IFIH1 mutation as causing SMS and leading to early arterial calcification and dental inflammation and resorption.

Singleton-Merten syndrome (SMS) is a rare disease with a phenotype of dental dysplasia. Currently, the underlying mechanism of this disease is unknown. In order to investigate the functional mechanism of the SMS tooth phenotypes, we isolated dental pulp tissue and established SMS primary pulp cells. These cells exhibited normal morphology and could be maintained in culture. Their ability to express alkaline phosphatase and mineralize was confirmed by in vitro staining. A comparative osteogenesis polymerase chain reaction array analysis was performed revealing 22 genes up-regulated and 8 genes down-regulated greater than 2-fold in SMS versus unaffected pulp cells. Down-regulated genes included ALP, IGF2, TGFBR2 and COL1A1. Collagen type I was reduced in SMS cells as shown by Western blot analysis. Furthermore, matrix metallopeptidase 13 was found to be dramatically increased in SMS pulp cells. Our findings suggest that dentin mineralization is dysregulated in SMS and may contribute to the root phenotype found in this disease.

Now construction engineering and engineering research set much store by determination of completed works and building structures quality. At the same time, there are no special approved methods of quality determination. In this paper the authors are going to draw up a methodology of assessing the quality of welded joints of pipeline structures in case these works have to be examined forensically. The researchers analyse legislation requirements on forensic examinations technical regulations and practical experience and offer a methodology which makes it possible to conduct a formal expert examination in a proper legitimate way.

Pleiotrophin (PTN) is an extracellular matrix–associated growth factor and chemokine expressed in mesodermal and ectodermal cells. It plays an important role in osteoblast recruitment and differentiation. There is limited information currently available about PTN expression during odontoblast differentiation and tooth formation, and thus the authors aimed to establish the spatiotemporal expression pattern of PTN during mouse odontogenesis. Immortalized mouse dental pulp (MD10-D3, MD10-A11) and odontoblast-like (M06-G3) and ameloblast-like (EOE-3M) cell lines were grown and samples prepared for immunocytochemistry, Western blot, and conventional and quantitative PCR analysis. Effects of BMP2, BMP4, and BMP7 treatment on PTN expression in odontoblast-like M06-G3 cells were tested by quantitative PCR. Finally, immunohistochemistry of sectioned mice mandibles and maxillaries at developmental stages E16, E18, P1, P6, P10, and P28 was performed. The experiments showed that PTN, at both the mRNA and protein level, was expressed in all tested epithelial and mesenchymal dental cell lines and that the level of PTN mRNA was influenced differentially by the bone morphogenetic proteins. The authors observed initial expression of PTN in the inner enamel epithelium with prolonged expression in the ameloblasts and odontoblasts throughout their stages of maturation and strong expression in the terminally differentiated and enamel matrix–secreting ameloblasts and odontoblasts of the adult mouse incisors and molars.

Fabry disease is caused by an X-linked deficiency of the lysosomal enzyme α-galactosidase A (GLA) and has been treated successfully with enzyme replacement therapy (ERT). Gene therapy has been proposed as an alternative to ERT due to the presumed advantages of continuous, endogenous production of the therapeutic enzyme. GLA production in the liver and its therapeutic efficacy in the Fabry mouse have been demonstrated previously with various viral vector systems. In consideration of the potential advantages of using the salivary glands as endogenous GLA biosynthesis sites, we explored the feasibility of this approach in the Fabry mouse. GLA -/0 or -/- mice received an adenoviral vector (2 × 10(10) or 1 × 10(9) viral particles) expressing GLA to the right submandibular gland via oral cannulation of the submandibular duct. Four days later, animals were sacrificed; saliva, plasma, kidney, liver, and brain were collected and assayed using ELISA, Western blot, and a GLA enzymatic activity assay using both traditional fluorescence methods and isotope dilution mass spectrometry by following the U.S. EPA Method 6800. GLA activity was significantly elevated in the serum and liver of both treatment groups, and improvement in the kidney was marginally significant (P 0.069) in the high-dose group. Notably, we found that liver and salivary gland produce different glycoforms of the GLA transgene. Only small numbers of adenoviral genomes were observed in the livers of treated animals, but in four of 14 in the high-dose groups, liver levels of adenovirus exceeded 20 copies/μg, indicating that the sequestration in the salivary gland was imperfect at high doses. Taken together, these results indicate that the salivary gland-based gene therapy for Fabry disease is promising, and further studies with advanced viral vector gene delivery systems (e.g., adeno-associated virus) for long-term treatment appear to be warranted.

The Apert syndrome is a rare congenital disorder most often arising from S252W or P253R mutations in fibroblast growth factor receptor (FGFR2). Numerous studies have focused on the regulatory role of Apert FGFR2 signaling in bone formation, whereas its functional role in tooth development is largely unknown. To investigate the role of FGFR signaling in cell proliferation and odontogenic differentiation of human dental cells in vitro, we isolated dental pulp and enamel organ epithelia (EOE) tissues from an Apert patient carrying the S252W FGFR2 mutation. Apert primary pulp and EOE cells were established and shown to exhibit normal morphology and express alkaline phosphatase under differentiation conditions. Similar to control cells, Apert dental pulp and EOE cells expressed all FGFRs, with highest levels of FGFR1 followed by FGFR2 and low levels of FGFR3 and FGFR4. However, Apert cells had increased cell growth compared with control cells. Distinct from previous findings in osteoblast cells, gain-of-function S252W FGFR2 mutation did not upregulate the expression of epidermal growth factor receptor (EGFR) and platelet-derived growth factor receptor (PDGFRα), but elevated extracellular signal-regulated kinase (ERK) signaling in cells after EGF stimulation. Unexpectedly, there was little effect of the S252W mutation on odontogenic gene expression in dental pulp and EOE cells. However, after inhibition of total FGFR signaling or ERK signaling, the expression of odontogenic genes was upregulated in both dental cell types, indicating the negative effect of whole FGFR signaling on odontogenic differentiation. This study provides novel insights on FGFR signaling and a common Apert FGFR2 mutation in the regulation of odontogenic differentiation of dental mesenchymal and epithelial cells.

s of the 51st Workshop for Pediatric Research 51st Workshop for Pediatric Research Gottingen, Germany 16-17 April 2015 This supplement has not been sponsored. Meeting abstracts Meeting abstract Singleton-Merten Syndrome (SMS) is a rare autosomal-dominant disorder characterized by a variety of symptoms including extreme calcifications of the ascending aorta and cardiac valves, dental anomalies (early onset periodontitis, root resorption), psoriasis and widened medullary cavities of the phalanges with focal osteoporosis. Employing whole exome sequencing of five SMS individuals of three families we identified the missense mutation, c.2465G>A (p.Arg822Gln) in the interferon induced with helicase C domain 1 (IFIH1) gene. Additional Sanger sequencing confirmed co-segregation of the mutation with the disorder. IFIH1, encoding melanoma differentiation-associated protein 5 (MDA5), is a member of the RIG-I-like receptor family and functions as a cytoplasmic pattern recognition receptor recognizing viral double stranded RNA (dsRNA). Immunohistochemistry demonstrated the localization of MDA5 in all affected target tissues including heart, skin and cartilage. Functional analysis revealed that the IFIH1 c.2465G>A mutation enhanced MDA5 function in interferon beta induction after polyinosinic:polycytidylic acid (poly (I:C)) stimulation in vitro. This indicates that SMS-MDA5 is hyperactive to non-self dsRNA. According to additional in vitro studies, interferon signature genes including SIGLEC1 were upregulated in blood and dental cells derived from SMS individuals. Taken together, our data demonstrate that the MDA5 gain-of-function mutation p.Arg822Gln causes the autosomal dominant disorder SMS through dysregulation of the human innate immune response.

To explore gene therapy strategies for amelogenesis imperfecta (AI), a human ameloblast-like cell population was established from third molars of an AI-affected patient. These cells were characterized by expression of cytokeratin 14, major enamel proteins and alkaline phosphatase staining. Suboptimal transduction of the ameloblast-like cells by an adenovirus type 5 (Ad5) vector was consistent with lower levels of the coxsackie-and-adenovirus receptor (CAR) on those cells relative to CAR-positive A549 cells. To overcome CAR -deficiency, we evaluated capsid-modified Ad5 vectors with various genetic capsid modifications including "pK7" and/or "RGD" motif-containing short peptides incorporated in the capsid protein fiber as well as fiber chimera with the Ad serotype 3 (Ad3) fiber "knob" domain. All fiber modifications provided an augmented transduction of AI-ameloblasts, revealed following vector dose normalization in A549 cells with a superior effect (up to 404-fold) of pK7/RGD double modification. This robust infectivity enhancement occurred through vector binding to both α(v)β3/α(v)β5 integrins and heparan sulfate proteoglycans (HSPGs) highly expressed by AI-ameloblasts as revealed by gene transfer blocking experiments. This work thus not only pioneers establishment of human AI ameloblast-like cell population as a model for in vitro studies but also reveals an optimal infectivity-enhancement strategy for a potential Ad5 vector-mediated gene therapy for AI.

Odontogenic tumors occur within the jaw bones and may be derived from odontogenic epithelium or ectomesenchyme or contain active components of both tissue types. We investigated the gene expression profile of enamel matrix proteins (EMPs), genes related to osteogenesis, and the mineralization process in odontogenic tumor cell populations focusing on an ameloblastoma (AB-1), a keratocystic odontogenic tumor (KCOT-1), and a calcifying epithelial odontogenic tumor (CEOT-1). All cell populations were shown to be epithelial in origin by CK14 expression. All tested EMPs were expressed by all odontogenic tumor cell types, with higher transcript levels seen in the AB-1 population especially for AMEL, AMBN, and ODAM. CEOT-1 cell populations showed a greater content of ALP-positive cells as well as higher ALP mRNA levels. Using qRT-PCR, we found a higher expression of 8 genes in the CEOT-1 compared to the AB-1 and KCOT-1. In this study we demonstrated the establishment of AB-1, KCOT-1 and CEOT-1 cell populations. The unique gene expression profiles of AB-1, KCOT-1, and CEOT-1 cells and their interactions with the surrounding microenvironment may support their unique tumor development, progression, and survival.

One hallmark of AIDS progression is a decline in CD4+ T lymphocytes, though the mechanism is poorly defined. There is ample evidence that increased apoptosis is responsible for some, if not all, of the decline. Prior studies have shown that binding of cellular calmodulin to the envelope glycoprotein (Env) of HIV-1 increases sensitivity to fas-mediated apoptosis and that calmodulin antagonists can block this effect. We show that individual mutation of five residues in the C-terminal calmodulin-binding domain of Env is sufficient to significantly reduce fas-mediated apoptosis in transfected cells. The A835W mutation in the cytoplasmic domain of gp41 eliminated co-immunoprecipitation of Env with calmodulin in studies with stably transfected cells. Four point mutations (A835W, A838W, A838I, and I842R) and the corresponding region of HIV-1 HXB2 were cloned into the HIV-1 proviral vector pNL4-3 with no significant effect on viral production or envelope expression, although co-immunoprecipitation of calmodulin and Env was decreased in three of these mutant viruses. Only wild-type envelope-containing virus induced significantly elevated levels of spontaneous apoptosis by day 5 post-infection. Fas-mediated apoptosis levels positively correlated with the degree of calmodulin co-immunoprecipitation, with the lowest apoptosis levels occurring in cells infected with the A835W envelope mutation. While spontaneous apoptosis appears to be at least partially calmodulin-independent, the effects of HIV-1 Env on fas-mediated apoptosis are directly related to calmodulin binding.

The work comprises: 1 Determination by nuclear magnetic resonance method of the conformation of the imino group of pyridoxal-P oxime in solution. It has been found to be nearly coplanar with the aromatic ring. 2 Theoretical calculation by the method of atom-atom potentials of the permitted conformations of pyridoxal-P imine and its analogs: 6-methylpyridoxal-P and 5′-methylpyridoxal-P. There have been found seven favourable conformations for pyridoxal-P imine, some of which were prohibited in the analogs mentioned. 3 Experimental estimation of the conformation of pyridoxal-P imine in the active site of aspartate aminotransferase with the use of the above sterically hindered analogs and 5′-deoxy-5′-carboxy-methylenepyridoxal analog. In result, the number of the possible conformations for pyridoxal-P imine in the active site has been reduced to a pair of symmetrical conformations.