Nucleolar Organizer Research Articles

The different subtelomeric structure among 1RS arms in wheat-rye 1BL.1RS translocations affecting their meiotic recombination and inducing their structural variation

BackgroundThe 1RS arm of wheat-rye 1BL.1RS translocations contains several subtelomeric tandem repeat families. To study the effect of the difference in the composition of these tandem repeats on the meiotic recombination of 1RS arms can help to enrich the genetic diversity of 1BL.1RS translocation chromosomes.ResultsFive wheat-rye 1BL.1RS translocation cultivars/lines were used to build two cross combinations including group 1 (20T401 × Zhou 8425B, 20T401 × Lovrin 10 and 20T401 × Chuannong 17) and group 2 (20T360-2 × Zhou 8425B, 20T360-2 × Lovrin 10 and 20T360-2 × Chuannong 17). Oligonucleotide (oligo) probes Oligo-s120.3, Oligo-TR72, and Oligo-119.2-2 produced the same signal pattern on the 1RS arms in lines 20T401 and 20T360-2, and another signal pattern in the three cultivars Zhou 8425B, Lovrin 10 and Chuannong 17. The Oligo-pSc200 signal disappeared from the 1RS arms of the line 20T401, and the signal intensity of this probe on the 1RS arms of the line 20T360-2 was weaker than that of the three cultivars. The five cultivars/lines had the same signal pattern of the probe Oligo-pSc250. The recombination rate of 1RS arms in group 1 was significantly lower than that in group 2. In the progenies from group 1, unequal meiotic recombination in the subtelomeric pSc119.2 and pSc250 tandem repeat regions, and a 1BL.1RS with inversion of 1RS segment between the pSc200 and the nucleolar organizer region were found.ConclusionsThis study provides a visual tool to detect the meiotic recombination of 1RS arms. The meiotic recombination rate of 1RS arms was affected by the variation of pSc200 tandem repeat, indicating the similar composition of subtelomeric tandem repeats on these arms could increase their recombination rate. These results indicate that the 1RS subtelomeric structure will affect its recombination, and thus the localization of genes on 1RS by means of meiotic recombination might also be affected.

The initial steps toward the formation of somatic tissue banks and cell cultures derived from captive Antillean manatee (Trichechus manatus manatus) skin biopsies.

The declining population of the Antillean manatee caused by ecosystem degradation and rising pollution has prompted interest in developing conservation strategies for this species. Given this scenario, somatic tissue banks are important tools for acquiring knowledge about the species, as well as for obtaining somatic cells for biotechnological and ecotoxicological applications. Therefore, we aimed to assess the effects of slow freezing (SF) and solid-surface vitrification (SSV) of the dermis of captive Antillean manatees on the histology and ultrastructure of the tissue and cell viability in culture. While the SSV did not change the dermis thickness, the SF maintained the tissue proliferative potential, assessed by the nucleolar organizer region area, similar to noncryopreserved tissues. Moreover, both techniques reduced the number of fibroblasts and increased the percentage of collagen fibers. Nevertheless, only tissues cryopreserved with SF and noncryopreserved tissues were able to produce cells after in vitro culture. Although SF did not alter cell viability and proliferative activity, cells derived from cryopreserved tissues showed decreased metabolism, altered apoptosis, increased levels of reactive oxygen species, and mitochondrial membrane potential compared to cells from noncryopreserved tissues. In summary, we demonstrated for the first time that Antillean manatee somatic tissues can be cryopreserved by SF, and cells can be obtained after in vitro culture. Improvements in cryopreservation conditions, especially vitrification, of somatic samples are needed to increase the quality of somatic tissue banks in this species.

Association of Proliferative Indices With Various Grades of Breast Carcinoma.

Various grades of breast carcinoma and proliferative indices used as nuclear protein Ki-67 and argyrophilic nucleolar organizer regions (AgNOR) are being compared to each other. In this observational cross-sectional investigation, 42 breast biopsies from questionable breast areas were collected and preserved in formalin and paraffin before the tissue blocks were made. A thorough medical history regarding the breast tumor and thorough physical examination results were recorded. Two sections were produced, one stained with an immunohistochemical marker called Ki-67 and the other with a unique stain called AgNOR. Grade I in Nottingham was found to be highest in subjects with Ki-67 1%, grade II in subjects with Ki-67 1-10%, and grade III in subjects with Ki-67>10%. Therefore, a higher Ki-67 score and a higher Nottingham grade were more closely associated. The mean AgNOR score was determined to be highest in Nottingham grade III and lowest in Nottingham grade I. In contrast to grade I and grade II of carcinoma (CA) breast, where there was no statistically significant association between Ki-67 and AgNOR, grade III of CA breast showed a statistically significant link between Ki-67 and AgNOR. Proliferation has been identified as a distinctive feature of cancer and as a key factor in the prognosis of the disease.

Spatial organization and dynamics of chromosomes and microtubules during barley mitosis.

Mitosis and cytokinesis are fundamental processes through which somatic cells increase their numbers and allow plant growth and development. Here, we analyzed the organization and dynamics of mitotic chromosomes, nucleoli, and microtubules in living cells of barley root primary meristems using a series of newly developed stable fluorescent protein translational fusion lines and time-lapse confocal microscopy. The median duration of mitosis from prophase until the end of telophase was 65.2 and 78.2 min until the end of cytokinesis. We showed that barley chromosomes frequently start condensation before mitotic pre-prophase as defined by the organization of microtubules and maintain it even after entering into the new interphase. Furthermore, we found that the process of chromosome condensation does not finish at metaphase, but gradually continues until the end of mitosis. In summary, our study features resources for in vivo analysis of barley nuclei and chromosomes and their dynamics during mitotic cell cycle.

A complete telomere-to-telomere assembly of the maize genome

A complete telomere-to-telomere (T2T) finished genome has been the long pursuit of genomic research. Through generating deep coverage ultralong Oxford Nanopore Technology (ONT) and PacBio HiFi reads, we report here a complete genome assembly of maize with each chromosome entirely traversed in a single contig. The 2,178.6 Mb T2T Mo17 genome with a base accuracy of over 99.99% unveiled the structural features of all repetitive regions of the genome. There were several super-long simple-sequence-repeat arrays having consecutive thymine–adenine–guanine (TAG) tri-nucleotide repeats up to 235 kb. The assembly of the entire nucleolar organizer region of the 26.8 Mb array with 2,974 45S rDNA copies revealed the enormously complex patterns of rDNA duplications and transposon insertions. Additionally, complete assemblies of all ten centromeres enabled us to precisely dissect the repeat compositions of both CentC-rich and CentC-poor centromeres. The complete Mo17 genome represents a major step forward in understanding the complexity of the highly recalcitrant repetitive regions of higher plant genomes.

New insights on the evolution of nucleolar dominance in newly resynthesized hexaploid wheat Triticum zhukovskyi.

Nucleolar dominance (ND) is a widespread epigenetic phenomenon in hybridizations where nucleolus transcription fails at the nucleolus organizer region (NOR). However, the dynamics of NORs during the formation of Triticum zhukovskyi (GGAu Au Am Am ), another evolutionary branch of allohexaploid wheat, remains poorly understood. Here, we elucidated genetic and epigenetic changes occurring at the NOR loci within the Am , G, and D subgenomes during allopolyploidization by synthesizing hexaploid wheat GGAu Au Am Am and GGAu Au DD. In T. zhukovskyi, Au genome NORs from T. timopheevii (GGAu Au ) were lost, while the second incoming NORs from T. monococcum (Am Am ) were retained. Analysis of the synthesized T. zhukovskyi revealed that rRNA genes from the Am genome were silenced in F1 hybrids (GAu Am ) and remained inactive after genome doubling and subsequent self-pollinations. We observed increased DNA methylation accompanying the inactivation of NORs in the Am genome and found that silencing of NORs in the S1 generation could be reversed by a cytidine methylase inhibitor. Our findings provide insights into the ND process during the evolutionary period of T. zhukovskyi and highlight that inactive rDNA units may serve as a 'first reserve' in the form of R-loops, contributing to the successful evolution of T. zhukovskyi.

Reaching for the off switch in nucleolar dominance.

Nucleolus organizer regions (NORs) are eukaryotic chromosomal loci where ribosomal RNA (rRNA) genes are clustered, typically in hundreds to thousands of copies. Transcription of these rRNA genes by RNA polymerase I and processing of their transcripts results in the formation of the nucleolus, the sub-nuclear domain in which ribosomes are assembled. Approximately 90 years ago, cytogenetic observations revealed that NORs inherited from the different parents of an interspecific hybrid sometimes differ in morphology at metaphase. Fifty years ago, those chromosomal differences were found to correlate with differences in rRNA gene transcription and the phenomenon became known as nucleolar dominance. Studies of the past 30 years have revealed that nucleolar dominance results from selective rRNA gene silencing, involving repressive chromatin modifications, and occurs in pure species as well as hybrids. Recent evidence also indicates that silencing depends on the NOR in which an rRNA gene is located, and not on the gene's sequence. In this perspective, we discuss how our thinking about nucleolar dominance has shifted over time from the kilobase scale of individual genes to the megabase scale of NORs and chromosomes and questions that remain unanswered in the search for a genetic and biochemical understanding of the off switch.

Switch them off or not: selective rRNA gene repression in grasses.

Nucleolar dominance (ND) is selective epigenetic silencing of 35-48S rDNA loci. In allopolyploids, it is frequently manifested at the cytogenetic level by the inactivation of nucleolar organiser region(s) (NORs) inherited from one or several evolutionary ancestors. Grasses are ecologically and economically one of the most important land plant groups, which have frequently evolved through hybridisation and polyploidisation events. Here we review common and unique features of ND phenomena in this monocot family from cytogenetic, molecular, and genomic perspectives. We highlight recent advances achieved by using an allotetraploid model grass, Brachypodium hybridum, where ND commonly occurs at a population level, and we cover modern genomic approaches that decipher structural features of core arrays of NORs.

Allium cytogenetics: a critical review on the Indian taxa.

The genus Allium Linnaeus, 1753 (tribe Allieae) contains about 800 species worldwide of which almost 38 species are reported in India, including the globally important crops (onion, garlic, leek, shallot) and many wild species. A satisfactory chromosomal catalogue of Allium species is missing which has been considered in the review for the species occurring in India. The most prominent base number is x=8, with few records of x=7, 10, 11. The genome size has sufficient clues for divergence, ranging from 7.8 pg/1C to 30.0 pg/1C in diploid and 15.16 pg/1C to 41.78 pg/1C in polyploid species. Although the karyotypes are seemingly dominated by metacentrics, substantial variation in nucleolus organizing regions (NORs) is noteworthy. The chromosomal rearrangement between A.cepa Linnaeus, 1753 and its allied species has paved way to appreciate genomic evolution within Allium. The presence of a unique telomere sequence and its conservation in Allium sets this genus apart from all other Amaryllids and supports monophyletic origin. Any cytogenetic investigation regarding NOR variability, telomere sequence and genome size in the Indian species becomes the most promising field to decipher chromosome evolution against the background of species diversity and evolution, especially in the Indian subcontinent.

Evaluation of the Cytological Changes of the Oral Mucosa Among Smokers in Al Madinah Al Munawara Using Argyrophilic Nucleolar Organizer Region (AgNOR) Counts and Papanicolaus Stain.

Objective To evaluate the cytological changes of the oral mucosa among smokers using Argyrophilic nucleolar organizer region (AgNOR) counts and Papanicolaou (Pap) staining. Methodology The oral mucosal exfoliate smears of 500 individuals (200 nonsmokers and 300 smokers) aged between 18 and 80 years were prepared in Al Madinah. TheAgNOR count and Pap stain were used to generate a cytogenic smear to assess the presence of cytological changes suggestive of atypia, inflammation, dysplasia, keratinization, and proliferative activity of epithelial cells. Results Smokers have a considerably higher number of AgNORs per nucleus than nonsmokers (1.99 3.53 vs. 0.42 1.22). There were inflammatory changes in 127 (42.3%) of the cases and 40 (20%) of the controls. Multinucleated cells and atypia were found in 33 (11%) and 14 (4.5%) of the casesbut not in the controls. The results indicate higher proliferative activity in smoking patients compared to nonsmoking patients, even in the absence of clinical lesions. Conclusion To detect the effects of smoking on the oral mucosa, Pap staining alone is insufficient. Combining Pap staining with the AgNOR technique produces the desired results.

Massive expansion of sex-specific SNPs, transposon-related elements, and neocentromere formation shape the young W-chromosome from the mosquitofish Gambusia affinis

BackgroundThe Western mosquitofish, Gambusia affinis, is a model for sex chromosome organization and evolution of female heterogamety. We previously identified a G. affinis female-specific marker, orthologous to the aminomethyl transferase (amt) gene of the related platyfish (Xiphophorus maculatus). Here, we have analyzed the structure and differentiation of the G. affinis W-chromosome, using a cytogenomics and bioinformatics approach.ResultsThe long arm of the G. affinis W-chromosome (Wq) is highly enriched in dispersed repetitive sequences, but neither heterochromatic nor epigenetically silenced by hypermethylation. In line with this, Wq sequences are highly transcribed, including an active nucleolus organizing region (NOR). Female-specific SNPs and evolutionary young transposable elements were highly enriched and dispersed along the W-chromosome long arm, suggesting constrained recombination. Wq copy number expanded elements also include female-specific transcribed sequences from the amt locus with homology to TE. Collectively, the G. affinis W-chromosome is actively differentiating by sex-specific copy number expansion of transcribed TE-related elements, but not (yet) by extensive sequence divergence or gene decay.ConclusionsThe G. affinis W-chromosome exhibits characteristic genomic properties of an evolutionary young sex chromosome. Strikingly, the observed sex-specific changes in the genomic landscape are confined to the W long arm, which is separated from the rest of the W-chromosome by a neocentromere acquired during sex chromosome evolution and may thus have become functionally insulated. In contrast, W short arm sequences were apparently shielded from repeat-driven differentiation, retained Z-chromosome like genomic features, and may have preserved pseudo-autosomal properties.

Nicotianamine synthase activity affects nucleolar iron accumulation and impacts rDNA silencing and RNA methylation in Arabidopsis.

In plant cells, a large pool of iron (Fe) is contained in the nucleolus, together with that in chloroplasts and mitochondria. A central determinant for intracellular distribution of Fe is nicotianamine (NA) generated by nicotianamine synthase (NAS). Here, we characterized Arabidopsis thaliana plants with disrupted NAS genes to modify accumulation of nucleolar iron and understand its role in nucleolar functions and more specifically in rRNA gene expression. We found that nas124 triple mutant plants, which contain lower quantities of the iron ligand NA, also contain less iron in the nucleolus. This is concurrent with the expression of normally silenced rRNA genes from Nucleolar Organizer Regions 2 (NOR2). Notably, in nas234 triple mutant plants, which also contain lower quantities of NA, nucleolar iron and rDNA expression are not affected. In contrast, in both nas124 and nas234, specific RNA modifications are differentially regulated in a genotype dependent manner. Taken together the data point out the impact of specific NAS activities in RNA gene expression. We discuss the interplay between NA and nucleolar iron with rDNA functional organization and RNA methylation.

Cytogenetic evidence of hybridization in Prosopis alba, P. hassleri, and P. fiebrigii in the semiarid-humid Chaco transition

Hybridization is a common and widespread phenomenon in vascular plants, leading to genetic exchange between related species. Interspecific hybridization has been extensively reported in Prosopis, a key genus of the Gran Chaco Americano, when species grow in sympatry or have adjacent distributions. Here, we performed a cytogenetic study in a hybrid zone of Prosopis alba, P. hassleri, and P. fiebrigii in southern South America. We characterized the karyotypes of pure species and the putative interspecific hybrids using chromosome fluorescent banding. Two karyotypes according to the heterochromatin pattern were identified, one corresponding to P. alba and the other to P. hassleri and P. fiebrigii; hybrid individuals presented P. alba or P. hassleri/P. fiebrigii karyotypes. The karyotypic formula and the number of nucleolar organizer regions were the same for all the studied morphotypes. Chromosome similarity among different species of the genus allows a continued hybridization and introgression between species and lends support to the hypothesis of a relatively recent diversification of Prosopis. Studying karyotype variation within a population could be a novel approach to the cytogenetic study of hybrids in the future.

Karyotypic and Molecular Analysis of Pterygoplichthys pardalis (Castelnau 1855) from the Lower Amazon River.

Pterygoplichthys pardalis is an armored catfish native to South America and an important resource for the ornamental fish industry. Recently, several exotic populations have been introduced into rivers on five continents. Despite its commercial and environmental importance, P. pardalis is poorly studied from a genetic perspective. In this study, we analyzed the karyotype of P. pardalis from the Amazon River and molecular variations in the mitochondrial gene Cytochrome oxidase I (COI) between native and exotic populations. The karyotype presented diploid number 2n = 52 and NF = 100 without cytogenetic variation between males and females. Nucleolus organizer regions (Ag-NOR) in the distal region of the long arm of pair 12 coincided with the 18S hybridization signal, whereas 5S was syntenic to this chromosome but localized in the short arm. The constitutive heterochromatin was restricted in the distal regions of pairs 4, 12, 25, and 26. Telomeric probes showed only distal hybridization signals. The karyotype of P. pardalis diverged from that of its congeners, and COI molecular variation revealed four haplotypes. The Philippine population revealed the greatest diversity with three haplotypes, while haplotype H1 was the most abundant and observed in both native and exotic populations. This new genetic data contributes to species management and provides useful information from an aquaculture perspective.

Predictive assessment of micro RNA expression level and number of nucleolar organizer regions with follicular thyroid tumor of undetermined malignant potential

Introduction This article presents the current views on follicular thyroid tumor of undetermined malignant potential (FTUMP) taking into account the principles of WHO classification. Molecular genetic study with identification of mutation of some genes as well as determination of expression level of some microRNAs are given as methods for detection of potential predictors of oncodiagnostics. It was shown that the state of nucleus organizer regions is a marker of cell proliferation rate.The aim of the investigation was to estimate prognostic significance of expression level of some microRNAs and amount of regions of the nucleus organizers in the thyroid tissue at FTUMP to objectify approaches to development of adequate surgical tactics.Materials and methods Profile, microRNA expression level by real time PCR and regions of the nucleus organizers were studied in 98 cases of FTUMP which made up 4.75% of all cases of thyroid tumors operated on during four years.Results In 29 (29.6%) cases the spectrum of microRNA typical for malignant neoplasms was registered in the tissue of the FTUMP. In the remaining 69 (70.4%) cases out of 98 observations the spectrum and the expression level of microRNA corresponded to the follicular adenoma. Statistically significant differences in the average number of AgNORs and correlation between the cell area and the number of AgNORs granules were found within the formed subgroups.Discussion Increase of the mean number of AgNORs and the ratio of the nucleus area to the number of silver nitrate granules in the 2nd subgroup in comparison with the 1st one, as well as the appearance of the type II cells testifies to the appearance of the proliferating tumor cells in a new tumor growth and can be considered as prognostic criteria of tumor malignization. These results correlate with the findings of molecular-genetic study. Conclusion The data of the literature and the results obtained by studying the profile and the expression level of a number of microRNAs, morphometric characteristics and counting of thyrocyte nucleus organizer regions may serve as additional criteria for evaluation of the proliferative activity of the follicular epithelium in thyroid neoplasms, in particular to clarify the malignancy potential. Preoperatively diagnosed conditionally malignant FTUMP will allow to justify the necessity and amount of surgical intervention, and if a complex of criteria of conditionally benign FTUMP is revealed, to stick to the waiting tactics and refuse surgical intervention.

Structural variation among assembled genomes facilitates development of rapid and low-cost NOR-linked markers and NOR-telomere junction mapping in Arabidopsis.

Genome-wide structural variants we identified and new NOR-linked markers we developed would be useful for future genome-wide association studies (GWAS), and for new gene/trait mapping purposes. Bioinformatic alignment of the assembled genomes of Col-0 and Sha ecotypes of Arabidopsis thaliana revealed ~ 13,000 genome-wide structural variants involving simple insertions or deletions and repeat contractions or expansions. Using some of these structural variants, we developed new, rapid, and low-cost PCR-based molecular markers that are genetically linked to the nucleolus organizer regions (NORs). A. thaliana has two NORs, one each on chromosome 2 (NOR2) and chromosome 4 (NOR4). Both NORs are ~ 4Mb each, and hundreds of 45S ribosomal RNA (rRNA) genes are tandemly arrayed at these loci. Using previously characterized recombinant inbred lines (RILs) derived from Sha xCol-0 crosses, we validated the utility of the newly developed NOR-linked markers in genetically mapping rRNA genes and the associated telomeres to either NOR2 or NOR4. Lastly, we sequenced Sha genome using Oxford Nanopore Technology (ONT) and used the data to obtain sequences of NOR-telomere junctions, and with the help of RILs, we mapped them as new genetic markers to their respective NORs (NOR2-TEL2N and NOR4-TEL4N). The structural variants obtained from this study would serve as valuable data for genome-wide association studies (GWAS), and to rapidly design more genome-wide genetic (molecular) markers for new gene/trait mapping purposes.

Single Copies of the 5S rRNA Inserted into 45S rDNA Intergenic Spacers in the Genomes of Nototheniidae (Perciformes, Actinopterygii).

In the vast majority of Animalia genomes, the 5S rRNA gene repeats are located on chromosomes outside of the 45S rDNA arrays of the nucleolar organiser (NOR). We analysed the genomic databases available and found that a 5S rDNA sequence is inserted into the intergenic spacer (IGS) between the 45S rDNA repeats in ten species of the family Nototheniidae (Perciformes, Actinopterigii). We call this sequence the NOR-5S rRNA gene. Along with Testudines and Crocodilia, this is the second case of a close association between four rRNA genes within one repetitive unit in deuterostomes. In both cases, NOR-5S is oriented opposite the 45S rDNA. None of the three nucleotide substitutions compared to the canonical 5S rRNA gene influenced the 5S rRNA secondary structure. In transcriptomes of the Patagonian toothfish, we only found NOR-5S rRNA reads in ovaries and early embryos, but not in testis or somatic tissues of adults. Thus, we consider the NOR-5S gene to be a maternal-type 5S rRNA template. The colocalization of the 5S and 45S ribosomal genes appears to be essential for the equimolar production of all four rRNAs in the species that show rDNA amplification during oogenesis. Most likely, the integration of 5S and NOR rRNA genes occurred prior to Nototheniidae lineage diversification.

Actively transcribed rDNA and distal junction (DJ) sequence are involved in association of NORs with nucleoli

Although they are organelles without a limiting membrane, nucleoli have an exclusive structure, built upon the rDNA-rich acrocentric short arms of five human chromosomes (nucleolar organizer regions or NORs). This has raised the question: what are the structural features of a chromosome required for its inclusion in a nucleolus? Previous work has suggested that sequences adjacent to the tandemly repeated rDNA repeat units (DJ, distal junction sequence) may be involved, and we have extended such studies by addressing several issues related to the requirements for the association of NORs with nucleoli. We exploited both a set of somatic cell hybrids containing individual human acrocentric chromosomes and a set of Human Artificial Chromosomes (HACs) carrying different parts of a NOR, including an rDNA unit or DJ or PJ (proximal junction) sequence. Association of NORs with nucleoli was increased when constituent rDNA was transcribed and may be also affected by the status of heterochromatin blocks formed next to the rDNA arrays. Furthermore, our data suggest that a relatively small size DJ region, highly conserved in evolution, is also involved, along with the rDNA repeats, in the localization of p-arms of acrocentric chromosomes in nucleoli. Thus, we infer a cooperative action of rDNA sequence—stimulated by its activity—and sequences distal to rDNA contributing to incorporation into nucleoli. Analysis of NOR sequences also identified LncRNA_038958 in the DJ, a candidate transcript with the region of the suggested promoter that is located close to the DJ/rDNA boundary and contains CTCF binding sites. This LncRNA may affect RNA Polymerase I and/or nucleolar activity. Our findings provide the basis for future studies to determine which RNAs and proteins interact critically with NOR sequences to organize the higher-order structure of nucleoli and their function in normal cells and pathological states.

Argyrophilic nucleolar organizer regions as a promising biomarker for the detection of brain hypoxia levels caused by different doses of carbon monoxide poisoning.

The purpose of the study is to investigate whether there is any relationship between mean argyrophilic nucleolar organizing regions (AgNOR) number and total AgNOR area/total nuclear area (TAA/TNA) ratio and the levels of brain hypoxia after exposure to different acute doses of carbon monoxide (CO) gas. Each experimental group was exposed to CO gas (concentrations of 1,000, 3,000 and 5,000 ppm). Then, the rats were anesthetized, and blood samples were taken from the right jugular vein for carboxyhemoglobin levels detection. The rats were sacrificed on seventh day. AgNOR staining was applied to brain tissues. TAA/TNA and mean AgNOR number were detected for each nucleus. Significant differences were detected among all groups for TAA/TNA ratio, mean AgNOR number and carboxyhemoglobin level. According to a double comparison of groups, the differences between control and 1,000 ppm, control and 3,000 ppm, control and 5,000 ppm, and between 1,000 and 5,000 ppm were significant for TAA/TNA ratio. When mean AgNOR number was considered, significant differences were detected between control and 1,000 ppm, control and 3,000 ppm, control and 5,000 ppm, and between 1,000 and 3,000 ppm. AgNOR proteins may be used for early detection of the duration, intensity, and damage of brain injury caused by CO poisoning. Thus, effective treatment strategies can be developed for the prevention of hypoxic conditions.

Morphological criteria for Pipistrellus pygmaeus kidney indicators

At present, there is scientific and practical interest in the study of morphological and physiological features, criteria and tolerance of organs involved in protein metabolism in representatives of the order Chiroptera. Macro- and micrometric indicators of kidneys in soprano pipistrelle (Pipistrellus pygmaeus), as a result of adaptive transformations of the body to habitat conditions in the Bryansk region were studied. The study was conducted in the period from 2011 to 2022, 40 captures were carried out with a total of 481 individuals, of which 100 were selected for further study. On histological preparations of kidneys of soprano pipistrelle (Pipistrellus pygmaeus), morphometry of nephrons, podocyte parameters, nuclear-cytoplasmic ratio, areas of nucleolar organizers and their total area were studied. It was established that biological adaptation of the bats (Chiroptera), on the example of soprano pipistrelle (Pipistrellus pygmaeus), is manifested in development of biological properties of the species. The functional and protein-synthetic activity of cells, kidneys (cell volume, nucleus, cytoplasm and nuclear-cytoplasmic ratio), the number and increase in the total area of the argentophilic region of nucleolar organizers were determined by organ topography, gender and influence of anthropogenic negative environmental effects. The data obtained showed gender differences in female bats (Chiroptera) of Pipistrellus pygmaeus species living in an urban environment, having a large number in the colony, against the background of a combined anthropogenic load, under the influence of hydrocarbons, sulfur and nitrogen dioxides and suspended solids. It was found that phenotypic adaptation as an adaptation to flight triggers the main processes of biochemical cycles, the processes of endogenous intoxication and detoxification function in kidneys. In turn, it increases metabolism, which contributes to increase in the number of renal glomeruli and decrease in the cavity of renal glomerular capsule. New data characterizing nuclear-cytoplasmic ratio, number and total area of regions of nucleolar organizers in podocytes of glomeruli in kidneys of soprano pipistrelle (Pipistrellus pygmaeus), which may be a manifestation of genetic adaptation to environmental conditions, were obtained.