Marina V. Parchaykina’s research while affiliated with National Research Mordovia State University and other places

An original design of a simple bioreactor was used to fabricate two tubular, 200 cm long BC structures by culturing Komagataeibacter sucrofermentans B-11267 on a molasses medium. In addition, a tubular BC-based biocomposite with improved mechanical properties was obtained by combining cultivation on the molasses medium with in situ chemical modification by polyvinyl alcohol (PVA). Moreover, the present study investigated the BC production by the K. sucrofermentans B-11267 strain on the media with different molasses concentrations under agitated culture conditions. The dynamics of sugar consumption during the cultivation were studied by HPLC. The structure and physicochemical properties of BC and tubular BC structures were characterized by FTIR spectroscopy and X-ray diffraction (XRD). Thus, the findings indicate that K. sucrofermentans B-11267, when cultivated in a molasses medium, which is such a cheap waste product in the sugar industry, forms a significant amount of BC with a high crystallinity degree. The BC tubular structures demonstrated great potential for their application in biomedicine as artificial blood vessels and conduits for nerve regeneration.

The changes in lipid composition and phospholipase activity in damaged somatic nerves were studied against the background of the action of potassium hyaluronate and insulin-like growth factor-1. It has been shown that nerve cutting is accompanied by an increase in phospholipase A2 activity, resulting in an accumulation of lysophospholipids and free fatty acids, as well as an increase in phosphatidylinositol levels and a decrease in diacylglycerol content, which is most likely due to inactivation of phosphoinositide-specific phospholipase C against the background of injury to the nerve conductor. The introduction of potassium hyaluronate and insulin-like growth factor-1 enhances the recovery processes in the injured nerve conductor, however, the mechanisms of their action remain different. According to the literature data and the results of our own research, the action of potassium hyaluronate and insulin-like growth factor-1 is realized as a result of the launch of signaling pathways associated with the regulation of the activity of enzymes from the phospholipase family. At the same time, our data on a decrease in the activity of phospholipase A2 and the absence of significant changes in the level of phosphatidylinositol and diacylglycerol indicate that potassium hyaluronate most likely exerts its effect through the PL A2-mediated pathway. In addition, it was shown that against the background of the action of IGF-1, an intensification of phosphoinositide metabolism is observed, which is explained by the activation of phosphoinositidespecific phospholipase C. According to the literature, the launch of the phospholipase C-mediated mechanism is accompanied by the formation of components of the phosphatidylinositol 3-kinase signaling pathway involved in stimulation of the expression of various transcription factors necessary for axonal regeneration and restoration of the functioning of injured nerve conductors.

One of the pressing issues in regenerative medicine is the restoration of somatic nerve function after injury. In this study, extraction methods were used to obtain lipids from nervous tissue, followed by chromatographic separation, quantitative analysis via densitometry, and qualitative and quantitative analyses of the fatty acid composition through gas chromatography. The results showed that nerve cutting results in the accumulation of all forms of phosphoinositides and a decrease in diacylglycerol (DAG) levels in both the proximal and distal segments of the nerve conductor. This phenomenon is likely attributable to the inactivation of phosphoinositide-specific phospholipase C and the activation of lipolytic enzymes, particularly phospholipases A1 and A2, resulting in an increase in the amount of free fatty acids (FFAs). The intramuscular administration of insulin-like growth factor-1 (IGF-1) was associated with enhanced phosphoinositide metabolism, increased DAG levels, reduced FFA levels, and a redistribution of fatty acids within the studied lipid fractions. The registration method of action potentials demonstrated the restoration of nerve conduction in the proximal segment of somatic nerves following the introduction of IGF-1. This correlates with our findings regarding alterations in the lipid fraction composition of damaged nerve conductors in response to the drug’s effects. Most likely, IGF-1 exerts its effects through activation of the phosphoinositide-specific phospholipase C and phosphatidylinositol-3 kinase signaling pathways, which are necessary for axonal regeneration and the restoration of functioning damaged nerve conductors.

The content of neurotrophic factors in damaged somatic nerves under the action of the drug «Semax» was studied and their role in the regulation of regenerative processes in injured nerve conductors was established. It has been shown that intramuscular administration of the drug is accompanied by a significant increase in the level of NGF and NT-3 both in the proximal and distal parts of the nerve. At the same time, there are no significant changes in the quantitative content of neuroregulin-1 against the background of its use. The data obtained suggest that one of the mechanisms of action of Semax is its ability to interact with Schwann cells and stimulate the release of NGF and NT-3, which facilitate the regeneration of damaged axons and do not affect the synthesis of neuroregulin-1. In addition, the study of the quantitative content of individual protein fractions showed that the drug «Semax» has the most pronounced effect on the level of neurofilament-H in both segments of the nerve conductor, which indicates the important role and activation of the mitogen-activated protein kinase (MAPK / ERK) signalling pathway, which regulates processes of cytoskeletal protein synthesis and axon growth. Nevertheless, it was shown that in the variant of the experiment using Semax, there was a decrease in the level of GAP-43, which is a key marker of axonal growth, both in the proximal and distal segments of the nerve. The data obtained most likely indicate that the intramuscular administration of the drug does not affect the processes of axon growth, but is aimed at maintaining the survival of neurons and accelerated restoration of the functional state of nerve fibres, which is also confirmed by the appearance of an action potential and the ability of the nerve to conduct it against the background of the use of the Semax drug.

Recently, degradable biopolymers have become increasingly important as potential environmentally friendly biomaterials, providing a wide range of applications in various fields. Bacterial exopolysaccharides (EPSs) are biomacromolecules, which due to their unique properties have found applications in biomedicine, foodstuff, textiles, cosmetics, petroleum, pharmaceuticals, nanoelectronics, and environmental remediation. One of the important commercial polysaccharides produced on an industrial scale is xanthan. In recent years, the range of its application has expanded significantly. Bacterial cellulose (BC) is another unique EPS with a rapidly increasing range of applications. Due to the great prospects for their practical application, the development of their highly efficient production remains an important task. The present review summarizes the strategies for the cost-effective production of such important biomacromolecules as xanthan and BC and demonstrates for the first time common approaches to their efficient production and to obtaining new functional materials for a wide range of applications, including wound healing, drug delivery, tissue engineering, environmental remediation, nanoelectronics, and 3D bioprinting. In the end, we discuss present limitations of xanthan and BC production and the line of future research.

Bacterial cellulose (BC) is currently one of the most popular environmentally friendly materials with unique structural and physicochemical properties for obtaining various functional materials for a wide range of applications. In this regard, the literature reporting on bacterial nanocellulose has increased exponentially in the past decade. Currently, extensive investigations aim at promoting the manufacturing of BC-based nanocomposites with other components such as nanoparticles, polymers, and biomolecules, and that will enable to develop of a wide range of materials with advanced and novel functionalities. However, the commercial production of such materials is limited by the high cost and low yield of BC, and the lack of highly efficient industrial production technologies as well. Therefore, the present review aimed at studying the current literature data in the field of highly efficient BC production for the purpose of its further usage to obtain polymer nanocomposites. The review highlights the progress in synthesizing BC-based nanocomposites and their applications in biomedical fields, such as wound healing, drug delivery, tissue engineering. Bacterial nanocellulose-based biosensors and adsorbents were introduced herein.

It has been shown that the intensification of oxidative processes is observed when somatic nerves of rats are damaged. Accumulation of malondialdehyde occurs, and the phase properties of the lipid bilayer change, especially in the distal part of the nerve. Under the same conditions, there are multidirectional changes in the activity of antioxidant enzymes, superoxide dismutase (SOD) activity decreases, and catalase (CAT) activity increases. Under the action of resveratrol, there is a decrease in the number of TBA-active products in both areas of the damaged nerve. Alongside resveratrol action, SOD and CAT activity tends to return towards the control values. Similar patterns are observed in the action of resveratrol on the phase states of lipids with the damage to somatic nerves. By summarizing the data obtained, it can be claimed that when the nerve is damaged, profound changes occur both in the lipid component and in the antioxidant system. Resveratrol has a stabilizing effect on the studied parameters, and a longer period of time is required for their complete recovery.

It has been shown that in the somatic nerve’s lipids, both during excitation and transection, changes occur with the composition of individual phospholipids and in phospholipids fatty acids, which changes the phase state of the myelin and nerve fiber axolemma lipid bilayer. A main contribution in the nerve degenerative processes is dependent on the composition phospholipid’s fatty acid changes during the activation of both Ca²⁺-dependent and Ca²⁺-independent phospholipase A2 forms. At the same time, we studded changes in phosphoinisitol (PI) and diacylglycerol (DAG), which depend on the phosphoinositide cycle function during nerve excitation and degeneration processes. It was found that myelin lipids and nerve fiber axolemmas are involved not only in the functioning of the peripheral nerves, but also the pathological processes underlying deep functional and structural disorders. The effect of resveratrol on regeneration processes in the damaged rat sciatic nerve has also been investigated.