Morphofunctional changes in the rat's liver of different ages after L-methionine administration

Background: Literature data on the effect of methionine on functional activity and, especially, on morphological changes in the liver parenchyma in animals of different ages are sporadic, and research results are often ambiguous. Aim: The purpose of this work was to study and compare the morphofunctional changes in the liver of rats of different ages on prolonged administration of L-methionine. Material and Methods: The experiment was performed on 48 male Wistar rats of 3 and 15 months of age. Animals of the experimental group received L-methionine at a dose of 250 mg/kg body weight in addition to the standard diet, daily for 21 days. Histological preparations were prepared from liver tissue by a standard technique. Morphometry was performed on digital images using the computer program «Image J». Succinate dehydrogenase activity and protein concentration were determined in the suspension of hepatocyte mitochondria. Results: It was revealed that 21-day administration of L-methionine to rats led to hypertrophy of the hepatocyte nucleus, an increase in the nuclear-cytoplasmic ratio, the number of binuclear hepatocytes, and the nucleolus in the cell nucleus. The relative area of ​​the sinusoids network increased by 50% in 3-month-old animals. This indicated a better blood filling of the liver parenchyma. The increase in succinate dehydrogenase activity and protein concentration was revealed in the suspension of hepatocyte mitochondria of the experimental rats. This indicated an increase in the mitochondria energy potential and protein-synthetic activity. Conclusions: The administration of prophylactic doses of methionine to healthy rats leads to the appearance of pronounced morphological and functional signs of increased activity of hepatocytes. The severity of this effect has a distinct age-dependent character. In young rats, it is more pronounced than in mature rats. The results of the study are important for practical medicine when using methionine for therapeutic and prophylactic purposes.

Synthetic Data Resource and Benchmarks for Time Cell Analysis and Detection Algorithms

Hippocampal CA1 cells take part in reliable, time-locked activity sequences in tasks that involve an association between stimuli, in a manner that tiles the interval between the stimuli. Such cells have been termed time cells. Here we adopt a first-principles approach to comparing diverse analysis and detection algorithms for identifying time cells. We developed a resource for generating synthetic activity datasets using calcium signals recorded in vivo from mouse hippocampus using 2-photon imaging, for template response waveforms. We assigned known, ground truth values for properties of time cells in this synthetic dataset, including noise, timing imprecision, hit-trial ratio and calcium event width. These datasets were the input to a pipeline for testing multiple algorithms for time cell detection to determine the conditions for which they were best suited, and evaluate their effective operating ranges. We find that most algorithms are sensitive to noise. Only a few methods benefit from larger event widths. Reassuringly, most methods are insensitive to timing imprecision, and exhibit successful time cell detection even at low hit trial ratios. Importantly, all methods show good concordance in identifying cells as time cells.

Manganese Is a Strong Specific Activator of the RNA Synthetic Activity of Human Polη

DNA polymerase η (Polη) is a translesion synthesis polymerase that can bypass different DNA lesions with varying efficiency and fidelity. Its most well-known function is the error-free bypass of ultraviolet light-induced cyclobutane pyrimidine dimers. The lack of this unique ability in humans leads to the development of a cancer-predisposing disease, the variant form of xeroderma pigmentosum. Human Polη can insert rNTPs during DNA synthesis, though with much lower efficiency than dNTPs, and it can even extend an RNA chain with ribonucleotides. We have previously shown that Mn2+ is a specific activator of the RNA synthetic activity of yeast Polη that increases the efficiency of the reaction by several thousand-fold over Mg2+. In this study, our goal was to investigate the metal cofactor dependence of RNA synthesis by human Polη. We found that out of the investigated metal cations, only Mn2+ supported robust RNA synthesis. Steady state kinetic analysis showed that Mn2+ activated the reaction a thousand-fold compared to Mg2+, even during DNA damage bypass opposite 8-oxoG and TT dimer. Our results revealed a two order of magnitude higher affinity of human Polη towards ribonucleotides in the presence of Mn2+ compared to Mg2+. It is noteworthy that activation occurred without lowering the base selectivity of the enzyme on undamaged templates, whereas the fidelity decreased across a TT dimer. In summary, our data strongly suggest that, like with its yeast homolog, Mn2+ is the proper metal cofactor of hPolη during RNA chain extension, and selective metal cofactor utilization contributes to switching between its DNA and RNA synthetic activities.

Morphofunctional transformations during the morphogenesis of the thyroid gland of the offspring of Wistar rats after intrauterine exposure to dexamethasone

Background. In recent years, the prevalence of thyroid pathologies of various origins among children in the world has reached a significantly high level. The use of glucocorticoids during pregnancy remains a debatable issue in obstetrics today, as they can both positively and negatively affect the processes of organ morphogenesis and be the cause of pathological conditions in the postnatal period. Objective: to establish the features of morphofunctional transformations during the morphogenesis of the thyroid gland of the offspring of rats at an early age in normal and after intrauterine action of dexamethasone. Methods. 108 thyroid glands of rats of 3 experimental groups were microscopically examined using histological and immunohistochemical methods, followed by statistical processing of the obtained results. Results. Against the background of high levels of total follicular thyrocytes per 1 day of life in animals that received prenatal dexamethasone, cytoplasmic expression of TgAb was expressed, which correlated with the indicators of nuclear and cytoplasmic Fox-1 expression. From the 7th to the 11th day, a decrease in the total number of thyrocytes per unit area was observed due to the accumulation of colloid in the follicles, an increase in Fox-1 cytoplasmic expression and a decrease in nuclear expression, against the background of increased proliferative activity. By day 21, Fox-1 cytoplasmic and nuclear expression were almost identical. There was a decrease in the intensity of TgAb expression in the cytoplasm of thyrocytes and its expression in the colloid, a decrease in the number of Ki-67 positive thyrocytes per conditional unit area compared with the previous observation period. Conclusion. It was found that prenatal exposure of dexamethasone causes the offspring accelerate the development of morphological structures of the thyroid gland, but functionally they are in a state of stress of both the synthesizing apparatus and the process of hormone excretion, which is expressed in the imbalance of immunohistochemical expression of Fox-1 and TgAb. Such thyrocytes with signs of disturbances in synthetic activity desquamate into the lumen of the follicles, while on the 11th day we compensatory increase in the proliferative activity of the thyroid epithelium.

INTERPRETATION OF CHORAL WORK AS A CREATIVE COMPONENT IN THE SYSTEM OF FACTORS OF PERFORMANCE SKILLS OF THE FUTURE TEACHER - MUSICIAN

The article considers the issues of training a future music teacher, substantiates the importance of musical performance in his professional development. The views of scientists on the interpretation of the concepts of "performance", "performing skills" are analyzed. The components that determine the performance skills are highlighted. The meaning of the concepts "creation" and "creativity" is specified, their differences are defined. The phenomenon of interpretation as a type of creative activity is analyzed. Different approaches of music teachers and scholars to the interpretation of the term "interpretive skills", which are manifested in analytical work with musical text, technical and performing skills, artistic taste, the performer's own attitude to the figurative content of a musical work and reflect the level of his creative abilities. The key provisions of the theory and practice of interpretive activity of the future music teacher are indicated. The stages of creation of interpretation of a choral work are singled out and the range of tasks of each stage is defined. Analysis of a musical work is considered as one of the components of interpretation. The focus is on the formation of interpretation skills during individual lessons in the class of choral conducting. Methods and forms of work are proposed to activate the creative thinking of students to expand the musical horizons. It was found that the state of creative search deepens the performer's knowledge of the musical image, forms the skills and abilities of full-fledged work on interpretation. Emphasis is placed on the peculiarities of reading the musical text, on the development of skills and abilities in the independent analysis of a musical work. The role of personal qualities of the student and own experience in creative process is defined. The peculiarities of the formation of interpretive abilities are characterized, in particular, the sketch study of works as one of the forms of analytical-synthetic activity of the student is singled out. It was found that musical interpretation is a key aspect of the performing activity of a future musician teacher.

Features of the expression of Fox-1 in rat’s thyroid after prenatal dexamethasone action

The purpose of the work was to establish the features of Fox-1 expression and distribution in the parenchyma of the thyroid gland of rats in the postnatal period of ontogeny in the norm and after intrauterine action of dexamethasone.Material and methods: thyroid gland of rats (162 animals) of the Wistar line at the age from 1 to 14 days of postnatal development. Experimentally, the animals were injected intrauterinely with a solution of dexamethasone at a dose of 0.05 ml at a dilution of 1:40 on the 18th day of the dated pregnancy. The material was examined using a set of methods of morphological studies (production of histological serial sections, survey microscopy, morphometry, immunohistochemistry and statistical processing).Results of the research. In the thyroid glands of neonatal prenatal dexamethasone, the parenchyma was well developed and consisted of hollow colloid-type follicles and single colloid-type microfollicles, and a bright cytoplasmic reaction with Fox-1 antibodies was observed throughout the organ parenchyma. In the thyroid glands of animals of the 3rd day of life, morphological changes occurred in all groups of the experiment. In animals of the experimental group, hollow follicles of colloidal type of small, medium and large diameter were chaotically visualized throughout the body, and large follicles of irregular shape with immunohistochemical weak or negative reaction with Fox-1 antibodies in thyrocytes and lumen without colloidal evidence, which detected a decrease in the specific synthetic activity in these thyrocytes. On day 7 in the experimental group in the flattened thyrocytes of overstretched follicles, the expression of Fox-1 was present only in the apical part. On days 11-14 of postnatal development in the thyroid glands of rats experimentally prenatally exposed to dexamethasone in the wall of large follicles with flattened epithelium began extrafollicular proliferation of thyrocytes on the background of visualization in the lumen of these follicles desquamated cells. Intensive perinuclear and cytoplasmic Fox-1 positive reaction was present in extrafollicular proliferating thyrocytes.Conclusions. 1. The detected changes in the first day of life in the thyroid gland of rats indicated that prenatal administration of dexamethasone affects the intensification of differentiation not only structural and functional units - follicles, but also a specific synthetic intracellular apparatus of thyrocytes, judging by the intensification of Fox-1. Thus, immature pre-mRNA is converted into mature mRNA, from which thyroid proteins, in particular thyroglobulin, are translated. By the time of birth, this process in the experimental group reaches a significant development, covering the entire parenchyma of the gland. 2. In rats prenatally receiving dexamethasone, the period of lactation was characterized by intense structural changes in the thyroid gland, in particular intracellularly in thyrocytes of monolayer flattened epithelium, the expression of Fox-1 antibodies was sharply reduced, which was then replaced by a bright cytoplasmic reaction in proliferative clusters and follicles of colloidal type of secretion, which is an adaptive-compensatory mechanism of intracellular enhancement of proliferation of synthesizing organelles in response to the restructuring of a significant number of existing follicles by hypofunctional type, aimed at maintaining normal levels of thyroid function.

Dermal extracellular matrix response to facetem implant: a randomised controlled experimental study

Background. A leading concept in modern regenerative medicine is the perspective of using own body resources to remodel organs and tissues via the formation of “living scaffold”. A pivotal role in the formation of dermal scaffold is played by fibroblasts that produce extracellular matrix (ECM).Aim. A study of the fibroblast activation mechanism mediating synthesis of the dermal ECM fibrillar component under the Facetem filler administration.Methods. The experimental trial was conducted in Wistar male rats (72 animals). Animals had 0.05 mL Facetem (Korea) injections subdermally. The filler is a calcium-containing product featuring gradual degradation delivered through structural microspheric properties of the Lattice-pore technology. Biological material was sampled at weeks 1 and 2 of months 1, 2, 3 and 5. Tissues were paraffin-embedded in standard histological assays and stained with Mallory’s trichrome, Picrosirius red in polarisation microscopy and immunohistochemistry with collagen types I, III and elastin antibodies (Abcam).Results. Collagen distribution in dermis and the filling zone suggests that collagen production occurs by week 2 of the Facetem filler placement followed by an increase in synthesised matrix volume to 4.39 ± 0.7 for collagen type I and 3.9 ± 0.2 for collagen type III (p < 0.05). The synthetic activity of fi broblasts reduces by month 3, albeit with collagen production remaining above control even by the end of month 5. Elastin synthesis also initiates by week 2 of the filler injection in dermis and grows by month 3.Conclusion. The presence of Facetem filler triggers a foreign body inflammatory response in dermis. This multifactorial process initiates with protein adsorption proceeding to dermal cell recruitment and modulation of fibroblasts and macrophages. Activation of these cell types induces neocollagenesis entailing the extracellular matrix synthesis and expansion in dermis.

Functions of the Essential Gene mraY in Cellular Morphogenesis and Development of the Filamentous Cyanobacterium Anabaena PCC 7120

Bacterial cell shape is determined by the peptidoglycan (PG) layer. The cyanobacterium Anabaena sp. PCC 7120 (Anabaena) is a filamentous strain with ovoid-shaped cells connected together with incomplete cell constriction. When deprived of combined nitrogen in the growth medium, about 5–10% of the cells differentiate into heterocysts, cells devoted to nitrogen fixation. It has been shown that PG synthesis is modulated during heterocyst development and some penicillin-binding proteins (PBPs) participating in PG synthesis are required for heterocyst morphogenesis or functioning. Anabaena has multiple PBPs with functional redundancy. In this study, in order to examine the function of PG synthesis and its relationship with heterocyst development, we created a conditional mutant of mraY, a gene necessary for the synthesis of the PG precursor, lipid I. We show that mraY is required for cell and filament integrity. Furthermore, when mraY expression was being limited, persistent septal PG synthetic activity was observed, resulting in increase in cell width. Under non-permissive conditions, filaments and cells were rapidly lysed, and no sign of heterocyst development within the time window allowed was detected after nitrogen starvation. When mraY expression was being limited, a high percentage of heterocyst doublets were found. These doublets are formed likely as a consequence of delayed cell division and persistent septal PG synthesis. MraY interacts with components of both the elongasome and the divisome, in particular those directly involved in PG synthesis, including HetF, which is required for both cell division and heterocyst formation.

Cell-Free Protein Synthesis by Diversifying Bacterial Transcription Machinery

We have evaluated several approaches to increase protein synthesis in a cell-free coupled bacterial transcription and translation system. A strong pargC promoter, originally isolated from a moderate thermophilic bacterium Geobacillus stearothermophilus, was used to improve the performance of a cell-free system in extracts of Escherichia coli BL21 (DE3). A stimulating effect on protein synthesis was detected with extracts prepared from recombinant cells, in which the E. coli RNA polymerase subunits α, β, β’ and ω are simultaneously coexpressed. Appending a 3′ UTR genomic sequence and a T7 transcription terminator to the protein-coding region also improves the synthetic activity of some genes from linear DNA. The E. coli BL21 (DE3) rna::Tn10 mutant deficient in a periplasmic RNase I was constructed. The mutant cell-free extract increases by up to four-fold the expression of bacterial and human genes mediated from both bacterial pargC and phage pT7 promoters. By contrast, the RNase E deficiency does not affect the cell-free expression of the same genes. The regulatory proteins of the extremophilic bacterium Thermotoga, synthesized in a cell-free system, can provide the binding capacity to target DNA regions. The advantageous characteristics of cell-free systems described open attractive opportunities for high-throughput screening assays.

Increased remodeling and impaired adaption to endurance exercise in desminopathy

Desminopathy the most common intermediate filament disease in humans. Desmin is an essential part of the filamentous network that aligns myofibrils, anchors nuclei and mitochondria, and connects the z-discs and the sarcolemma. We created a rat model with a mutation in R349P DES, analog to the most frequent R350P DES missense mutation in humans. To examine the effects of a chronic, physiological exercise stimulus on desminopathic muscle, we subjected R349P DES rats and their wildtype (WT) and heterozygous littermates to a treadmill running regime. We saw significantly lower running capacity in DES rats that worsened over the course of the study. We found indicators of increased autophagic and proteasome activity with running in DES compared to WT. Stable isotope labeling and LC-MS analysis displayed distinct adaptations of the proteomes of WT and DES animals at baseline as well as with exercise: While key proteins of glycolysis, mitochondria and thick filaments increased their synthetic activity with running in WT, these proteins were higher at baseline in DES and did not change with running. The results suggest an impairment in adaption to chronic exercise in DES muscle and a subsequent exacerbation in the functional and histopathological phenotype.