Nucleolar Organizer Research Articles

Effect of buscopan, a compound that alleviates cramps, on the developing nervous system of the chick embryo.

Buscopan is used to treat stomach cramps including those resulting from irritable bowel syndrome, bladder cramps, and pain related to menstruation. Its pregnancy category is determined as C. It has been shown in experimental animal studies that the drug has a negative effect on the embryo, but sufficient and well-controlled studies have not been conducted in humans. The aim of this study is to investigate effects of buscopan on the development of the neural tube (NT) in chick embryos. Sixty specific pathogen-free (SPF) fertilized eggs were used. SPF eggs were placed in an incubator and divided into six groups at 28 hr of incubation. Five different doses (low to high) of buscopan were injected sub-blastodermally.At the end of 48 hr, the embryos were evaluated morphologicallyand histopathologically. The argyrophilic nucleolar-organizing region (AgNOR) method was used in this study to determine the proliferation activity of cells in NT development in chick embryos. AgNOR number and total AgNOR area/nuclear area (TAA/NA) were detected for each embryo. Depending on the dose, the embryo's crown-rump length and somite number decreased (p < .05). Significant differences were detected among all groups for mean AgNOR number (p < .05) and TAA/NA ratio (p < .05). Considering the average count of AgNOR cells and TAA/NA ratio, it was found that there was a decrease in cell division depending on the dose. It was determined that buscopan treatment on chick embryos adversely affected early nervous system and NT development.

A New Burrowing Frog of the Odontophrynus americanus Species Group (Anura, Odontophrynidae) from Subtropical Regions of Argentina, Brazil, and Paraguay

A new species of frog of the genus Odontophrynus is described from grassland of the subtropical regions of Argentina, Brazil, and Paraguay based on morphological, osteological, bioacoustical, cytogenetic, and molecular evidence. The new species is characterized by having medium size; rostral and eye-nostril glandular warts well developed; several long glandular ridges, longitudinally oriented, on dorsum; several medium-sized, nearly rounded, dark-brown dorsal blotches; light mid-dorsal stripe continuous and well defined or restricted to the head and the urostyle regions; and mid-dorsal stripe, interorbital, and dorsolateral bands with a moderately whitish highlight, light brown, or reddish coloration. Additionally, the new species has a skull with nasals slightly separated both from each other and frontoparietals, and frontoparietal fontanelle not exposed. The advertisement call consists of a single multipulsed note with a dominant frequency of 820–1,121 Hz and a pulse rate of 99.3–140.7 pulses/s. The chromosomal complement is diploid with 2N = 2X = 22 chromosomes and nucleolar organizer regions on the interstitial regions of the short arm of chromosome pair 4. The phylogenetic analysis allowed us to recover the new species belonging to the O. americanus species group with genetic distances from its congeners ranging from 2.11 to 4.82% in a partial sequence of 16S ribosomal RNA gene. The new species is geographically isolated from the other currently known diploid species of the group, but in some localities is found in sympatry or syntopy with the tetraploid O. americanus.

Histone acetylation of 45S rDNA correlates with disrupted nucleolar organization during heat stress response in Zea mays L.

The role of the nucleolus in plant response to heat stress remains largely obscure. Our current efforts focused on exploring the underlying mechanism by which nucleolar disorganization is regulated in heat stressed-maize lines. Here, two maize lines, a heat-sensitive line, ZD958, and a heat-tolerant line, ZDH, were submitted to heat stress for investigating their association with the nucleolar disruption. Immunofluorescence staining showed that nucleolar disruption increased with prolonged treatment time. After heat treatment, a significant change in nucleolus organization was observed in the ZD958 line, but the ZDH line showed mild alteration. Moreover, actinomycin D (ActD)-induced nucleolus fission led to inhibition of maize growth under the normal condition. The ZD958 line exhibited a significant increase in the level of H3K9ac and H4K5ac of the 45S rDNA accompanied by a higher transcription of the 5'-external transcribed spacer (ETS) region, while the line ZDH showed a slight increase in histone acetylation levels and the transcriptional initiation at this site after heat treatment. To our knowledge, this is the first report providing a comparative insight between heat stress, rDNA histone modifications, and nucleolus disintegration in a heat-tolerant ZDH compared with a heat-sensitive line ZD958. Our investigation might assist maize breeders in obtaining heat-tolerant lines by targeting nucleoli using epigenetics.

Evolutionary pattern of karyotypes and meiosis in pholcid spiders (Araneae: Pholcidae): implications for reconstructing chromosome evolution of araneomorph spiders

BackgroundDespite progress in genomic analysis of spiders, their chromosome evolution is not satisfactorily understood. Most information on spider chromosomes concerns the most diversified clade, entelegyne araneomorphs. Other clades are far less studied. Our study focused on haplogyne araneomorphs, which are remarkable for their unusual sex chromosome systems and for the co-evolution of sex chromosomes and nucleolus organizer regions (NORs); some haplogynes exhibit holokinetic chromosomes. To trace the karyotype evolution of haplogynes on the family level, we analysed the number and morphology of chromosomes, sex chromosomes, NORs, and meiosis in pholcids, which are among the most diverse haplogyne families. The evolution of spider NORs is largely unknown.ResultsOur study is based on an extensive set of species representing all major pholcid clades. Pholcids exhibit a low 2n and predominance of biarmed chromosomes, which are typical haplogyne features. Sex chromosomes and NOR patterns of pholcids are diversified. We revealed six sex chromosome systems in pholcids (X0, XY, X1X20, X1X2X30, X1X2Y, and X1X2X3X4Y). The number of NOR loci ranges from one to nine. In some clades, NORs are also found on sex chromosomes.ConclusionsThe evolution of cytogenetic characters was largely derived from character mapping on a recently published molecular phylogeny of the family. Based on an extensive set of species and mapping of their characters, numerous conclusions regarding the karyotype evolution of pholcids and spiders can be drawn. Our results suggest frequent autosome–autosome and autosome–sex chromosome rearrangements during pholcid evolution. Such events have previously been attributed to the reproductive isolation of species. The peculiar X1X2Y system is probably ancestral for haplogynes. Chromosomes of the X1X2Y system differ considerably in their pattern of evolution. In some pholcid clades, the X1X2Y system has transformed into the X1X20 or XY systems, and subsequently into the X0 system. The X1X2X30 system of Smeringopus pallidus probably arose from the X1X20 system by an X chromosome fission. The X1X2X3X4Y system of Kambiwa probably evolved from the X1X2Y system by integration of a chromosome pair. Nucleolus organizer regions have frequently expanded on sex chromosomes, most probably by ectopic recombination. Our data suggest the involvement of sex chromosome-linked NORs in achiasmatic pairing.

Targeted Enrichment of rRNA Gene Tandem Arrays for Ultra-Long Sequencing by Selective Restriction Endonuclease Digestion.

Large regions of nearly identical repeats, such as the 45S ribosomal RNA (rRNA) genes of Nucleolus Organizer Regions (NORs), can account for major gaps in sequenced genomes. To assemble these regions, ultra-long sequencing reads that span multiple repeats have the potential to reveal sets of repeats that collectively have sufficient sequence variation to unambiguously define that interval and recognize overlapping reads. Because individual repetitive loci typically represent a small proportion of the genome, methods to enrich for the regions of interest are desirable. Here we describe a simple method that achieves greater than tenfold enrichment of Arabidopsis thaliana 45S rRNA gene sequences among ultra-long Oxford Nanopore Technology sequencing reads. This method employs agarose-embedded genomic DNA that is subjected to restriction endonucleases digestion using a cocktail of enzymes predicted to be non-cutters of rRNA genes. Most of the genome is digested into small fragments that diffuse out of the agar plugs, whereas rRNA gene arrays are retained. In principle, the approach can also be adapted for sequencing other repetitive loci for which gaps exist in a reference genome.

Comparative Distribution of Repetitive Sequences in the Karyotypes of Xenopus tropicalis and Xenopus laevis (Anura, Pipidae).

Xenopus laevis and its diploid relative, Xenopus tropicalis, are the most used amphibian models. Their genomes have been sequenced, and they are emerging as model organisms for research into disease mechanisms. Despite the growing knowledge on their genomes based on data obtained from massive genome sequencing, basic research on repetitive sequences in these species is lacking. This study conducted a comparative analysis of repetitive sequences in X. laevis and X. tropicalis. Genomic in situ hybridization (GISH) and fluorescence in situ hybridization (FISH) with Cot DNA of both species revealed a conserved enrichment of repetitive sequences at the ends of the chromosomes in these Xenopus species. The repeated sequences located on the short arm of chromosome 3 from X. tropicalis were not related to the sequences on the short arm of chromosomes 3L and 3S from X. laevis, although these chromosomes were homoeologous, indicating that these regions evolved independently in these species. Furthermore, all the other repetitive sequences in X. tropicalis and X. laevis may be species-specific, as they were not revealed in cross-species hybridizations. Painting experiments in X. laevis with chromosome 7 from X. tropicalis revealed shared sequences with the short arm of chromosome 3L. These regions could be related by the presence of the nucleolus organizer region (NOR) in both chromosomes, although the region revealed by chromosome painting in the short arm of chromosome 3L in X. laevis did not correspond to 18S + 28S rDNA sequences, as they did not colocalize. The identification of these repeated sequences is of interest as they provide an explanation to some problems already described in the genome assemblies of these species. Furthermore, the distribution of repetitive DNA in the genomes of X. laevis and X. tropicalis might be a valuable marker to assist us in understanding the genome evolution in a group characterized by numerous polyploidization events coupled with hybridizations.

CORRELATION OF BIOPSY AND AgNOR COUNTS IN PREMALIGNANT AND MALIGNANT LESIONS OF CERVIX

Background- Cervical cancer is the commonest cancer among women in developing countries. Screening methods like cervical cytology has brought down the incidence of cervical cancer. AgNOR represents Nucleolar organizer regions stained with silver and are related to cell proliferation rate and tumor malignant potential. The present study was aimed at evaluating the diagnostic role of AgNOR in cervical carcinogenesis. Material and Methods- The present study was conducted in the Pathology department of Gajra Raja Medical College, Gwalior from January 2019 to May 2020 on 500 patients who attended the Gynae OPD. Women of suspected cervical pathology and who underwent Pap smear test followed by subsequent biopsies were included. Results- AgNOR count in chronic cervicitis was 2.72±0.32, in CIN I was 4.02±0.38, in CIN II was 5.47±0.21 in CIN III was 5.59±0.18, in Well differentiated KSCC was 6.48±0.40 and in adenocarcinoma was 6.93±0.21. The study showed that the mean AgNOR count per nucleus was signicantly higher in CIN and malignant cervical lesions. Conclusion- AgNOR count is reproducible, simple, efcient and inexpensive method which can be used as an adjunct to histopathology and cytology especially in differentiating doubtful cases of CIN.

Argyrophilic Nucleolar Organizer Regions in Premalignant and Malignant Oral Lesion: A Quantitative and Qualitative Assessment

Background: Argyrophilic nucleolar organizer regions (AgNORs) has been considered to be useful indiagnostic pathology, mainly to distinguish benign lesions from their malignant counterparts.Aim: This study was done to evaluate the significance of various AgNOR parameters in differentiatingpremalignant and malignant oral lesions.Materials and Methods: The study was performed on thirty five archival tissues consisting of samplecomprised of five normal mucosa, fifteen premalignant lesions and fifteen malignant oral lesions. AgNORswere assessed both quantitatively and qualitatively. The data were analyzed using ANOVA and Chi squaretest.Results: Quantitatively and qualitatively significant difference was noticed. Quantitatively significantdifference in the mean value of AgNORs noticed between the premalignant and malignant lesions. In termsof qualitatively, the premalignant and malignant oral lesions differed significantly from normal mucosa.Conclusion: To conclude, the AgNOR count is the most appropriate marker to differentiate betweenpremalignant and malignant oral lesions.

Cytogenetic Analysis of Panaqolus tankei Cramer & Sousa, 2016 (Siluriformes, Loricariidae), an Ornamental Fish Endemic to Xingu River, Brazil

Despite conservation of the diploid number, a huge diversity in karyotype formulae is found in the Ancistrini tribe (Loricariidae, Hypostominae). However, the lack of cytogenetic data for many groups impairs a comprehensive understanding of the chromosomal relationships and the impact of chromosomal changes on their evolutionary history. Here, we present for the first time the karyotype of Panaqolus tankei Cramer & Sousa, 2016. We focused on the chromosomal characterization, using conventional and molecular cytogenetic techniques to unravel the evolutionary trends of this tribe. P. tankei, as most species of its sister group Pterygoplichthini, also possessess a conserved diploid number of 52 chromosomes. We observed heterochromatin regions in the centromeres of many chromosomes; pairs 5 and 6 presented interstitial heterochromatin regions, whereas pairs 23 and 24 showed extensive heterochromatin regions in their q arms. In situ localization of 18S rDNA showed hybridization signals correlating with the nucleolus organizer regions, which are located in the q arms of pair 5. However, the 5S rDNA was detected in the centromeric and terminal regions of the q arms of pair 8. (TTAGGG)_n hybridized only in the terminal regions of all chromosomes. Microsatellite in situ localization showed divergent patterns, (GA)₁₅ repeated sequences were restricted to the terminal regions of some chromosomes, whereas (AC)₁₅ and (GT)₁₅ showed a scattered hybridization pattern throughout the genome. Intraspecific comparative genomic hybridization was performed on the chromosomes of P. tankei to verify the existence of sex-specific regions. The results revealed only a limited number of overlapping hybridization signals, coinciding with the heterochromatin in centromeric regions without any sex-specific signals in both males and females. Our study provides a karyotype description of P. tankei, highlighting extensive differences in the karyotype formula, the heterochromatin regions, and sites of 5S and 18S rDNA, as compared with data available for the genus.

FoxA2 and RNA Pol II mediate human islet amyloid polypeptide turnover in ER-stressed pancreatic β-cells.

Here, we investigated transcriptional and trafficking mechanisms of human islet amyloid polypeptide (hIAPP) in normal and stressed β-cells. In high glucose-challenged human islets and rat insulinoma cells overexpressing hIAPP, cell fractionation studies revealed increased accumulation of hIAPP. Unexpectedly, a significant fraction (up to 22%) of hIAPP was found in the nuclear soluble and chromatin-enriched fractions of cultured human islet and rat insulinoma cells. The nucleolar accumulation of monomeric forms of hIAPP did not have any adverse effect on the proliferation of β-cells nor did it affect nucleolar organization or function. However, intact nucleolar organization and function were essential for hIAPP expression under normal and ER-stress conditions as RNA polymerase II inhibitor, α-amanitin, reduced hIAPP protein expression evoked by high glucose and thapsigargin. Promoter activity studies revealed the essential role of transcription factor FoxA2 in hIAPP promoter activation in ER-stressed β-cells. Transcriptome and secretory studies demonstrate that the biosynthetic and secretory capacity of islet β-cells was preserved during ER stress. Thus, the main reason for increased intracellular hIAPP accumulation is its enhanced biosynthesis under these adverse conditions.

Effect of Pethidine Hydrochloride on the Development of Neural Tube: A Genetic Analysis Study in a Chick Embryo Model

Neural tube defects are among the most frequent congenital abnormalities of the central nervous system. Progression of neural tube deficits is affected by hereditary predilection and environmental determinants. Pethidine (meperidine) is a fast and powerful opioid analgesic in U.S. Food and Drug Administration category C. There are reports about developmental anomalies due to this medication. The aim of this study was to investigate the effects of different doses of pethidine hydrochloride on neural tube development in a chick embryo model resembling the first month of vertebral growth in mammals. Seventy-five specific pathogen-free eggs were incubated for 28 hours and divided into 5 groups (including the control group), each consisting of 15 eggs. Pethidine hydrochloride was administered sub-blastodermically with a Hamilton microinjector in 4 different doses. Incubation was continued until the end of the 48th hour. Subsequently, all eggs were opened, and embryos were cut from the embryonic membranes and evaluated morphologically, genetically, and histopathologically. Crown-rump length, somite numbers, and silver-stained nucleolar organizer region (AgNOR) number averages, and total AgNOR/nuclear area ratios decreased in a dose-dependent manner. Examination of neural tube closure revealed statistically significant differences in all experimental groups (P<0.05). Messenger RNA levels of the BRE gene were decreased in pethidine hydrochloride-exposed embryos compared with the control group. Although this downregulation was not statistically significant, this decrease was striking with a 0.422-fold change in the fifth group. We demonstrated that pethidine hydrochloride affects neuronal development in chicken embryos. The teratogenic mechanism of pethidine hydrochloride is unclear; therefore, further investigation is required.

Nuclear-nucleolar relationships and nucleolar stress in hepatocytes in hyperhomocysteinemia

Hyperhomocysteinemia causes stress of the endoplasmic reticulum, which suggests the formation of nucleolar stress. The purpose of this work is to clarify the relationship between structural changes in the nucleus and the region of the nucleolar organizer in hyperhomocysteinemia to prove nucleolar stress in hyperhomo-cysteinemia, which can serve as an additional diagnostic marker of the disease. The object of the study was white mongrel rats with methionine-induced hyperhomocysteinemia. Histologic sections of the liver were stained with hematoxylin and eosin (to assess the histological structure of the organ, hepatocyte nuclei), ammonia silver (to analyze the areas of the nucleolar organizer - AgNORs). Morphometry has allowed to establish that hyperhomocysteinemia decreases the number of nuclei (1,86 times, p

Testis Torsiyonunda Rapamisin Tedavisinin Antioksidan Enzim Değişiklikleri ve AgNOR Üzerindeki Etkilerinin Değerlendirilmesi

Objective:Testicle torsion/detorsion cause ischemia. Rapamycin has immune suppressive and antioxidant defense mechanisms. Nucleolar-organizing regions(NORs) are loops of ribosomal DNA. Methods: To evaluate mean AgNOR number and total AgNOR area/total nuclear area(TAA/TNA) ratio and the relation between these proteins and rapamycin in the Torsion/Detorsion process of testes. The six groups as control, sham, early and late torsion-detorsion (ETD&amp;lt;D) groups, and early and late rapamycin treatment groups (ETD+R&amp;lt;D+R) were included. The TAA/TNA and mean AgNOR number of testes cells and biochemical analysis of GPx, SOD, and TBARS activities were detected. Results: Significant differences were detected among the groups for mean AgNOR number and TAA/TNA(p&amp;lt;0.05). For both mean AgNOR number and TAA/TNA, significant differences were found between control and ETD, between control and ETD+R, between control and LTD, between control and LTD+R. Also, a statistically significant relationship between both mean AgNOR numbers and TAA/TNA of testes cells and all the antioxidant enzymes (SOD, TBARS, and GPX) were detected(p&amp;lt;0.05). Conclusion: We may obtain information about the levels and duration of testes injury considering the levels of these proteins. Thus it can be said that these proteins may be used in the development of new and more effective therapeutic approaches to prevent the negative effects of T/D injury.

Trisomy 5p with bilateral congenital diaphragmatic hernia: a\xa0case report

BackgroundBilateral congenital diaphragmatic hernia (CDH) is very rare. A few studies have reported the pathogenic role of 5p in CDH.Case presentationA 23-year-old primigravida Japanese woman was referred for the following abnormal findings at 33 weeks of gestation: polyhydramnios, macroglossia, talipes equinovarus, and levocardia. A marker chromosome was detected by amniocentesis. Fluorescence in situ hybridization with whole chromosome paint 5 and nucleolus organizer region probes confirmed its origin from chromosome 5 and an acrocentric chromosome. The karyotype of the fetus was diagnosed as 47, XY, +mar. ish +mar(WCP5+). At 39 + 5 weeks, a 2462 g male infant was delivered, with a specific facial configuration. Bilateral CDH, hypoplasia of the corpus callosum, atrial septal defect, and hypothyroidism were also detected in the baby. The karyotype of the peripheral blood was consistent with that of the amniocentesis.ConclusionGenes coded on 5p might be associated with the pathogenesis of CDH; however, further investigation is required.

Ancient Origin of Two 5S rDNA Families Dominating in the Genus Rosa and Their Behavior in the Canina-Type Meiosis.

The genus Rosa comprises more than 100 woody species characterized by intensive hybridization, introgression, and an overall complex evolutionary history. Besides many diploid species (2n = 2x = 14) polyploids ranging from 3x to 10x are frequently found. Here we analyzed 5S ribosomal DNA in 19 species covering two subgenera and the major sections within subg. Rosa. In addition to diploids and polyploids with regular meiosis, we focused on 5x dogroses (Rosa sect. Caninae), which exhibit an asymmetric meiosis differentiating between bivalent- and univalent-forming chromosomes. Using genomic resources, we reconstructed 5S rDNA units to reveal their phylogenetic relationships. Additionally, we designed locus-specific probes derived from intergenic spacers (IGSs) and determined the position and number of 5S rDNA families on chromosomes. Two major 5S rDNA families (termed 5S_A and 5S_B, respectively) were found at variable ratios in both diploid and polyploid species including members of the early diverging subgenera, Rosa persica and Rosa minutifolia. Within subg. Rosa species of sect. Rosa amplified the 5S_A variant only, while taxa of other sections contained both variants at variable ratios. The 5S_B family was often co-localized with 35S rDNA at the nucleolar organizer regions (NOR) chromosomes, whereas the co-localization of the 5S_A family with NOR was only exceptionally observed. The allo-pentaploid dogroses showed a distinct distribution of 5S rDNA families between bivalent- and univalent-forming chromosomes. In conclusion, two divergent 5S rDNA families dominate rose genomes. Both gene families apparently arose in the early history of the genus, already 30 myrs ago, and apparently survived numerous speciation events thereafter. These observations are consistent with a relatively slow genome turnover in the Rosa genus.

Evolutionary insights into the genomic organization of major ribosomal DNA in ant chromosomes.

The major rDNA genes are composed of tandem repeats and are part of the nucleolus organizing regions (NORs). They are highly conserved and therefore useful in understanding the evolutionary patterns of chromosomal locations. The evolutionary dynamics of the karyotype may affect the organization of rDNA genes within chromosomes. In this study, we physically mapped 18S rDNA genes in 13 Neotropical ant species from four subfamilies using fluorescence in situ hybridization. Furthermore, a survey of published rDNA cytogenetic data for 50 additional species was performed, which allowed us to detect the evolutionary patterns of these genes in ant chromosomes. Species from the Neotropical, Palearctic, and Australian regions, comprising a total of 63 species from 19 genera within six subfamilies, were analysed. Most of the species (48 out of 63) had rDNA genes restricted to a single chromosome pair in their intrachromosomal regions. The position of rDNA genes within the chromosomes appears to hinder their dispersal throughout the genome, as translocations and ectopic recombination are uncommon in intrachromosomal regions because they can generate meiotic abnormalities. Therefore, rDNA genes restricted to a single chromosome pair seem to be a plesiomorphic feature in ants, while multiple rDNA sites, observed in distinct subfamilies, may have independent origins in different genera.

Human nucleoli comprise multiple constrained territories, tethered to individual chromosomes.

It is unknown how ribosomal gene (rDNA) arrays from multiple chromosomal nucleolar organizers (NORs) partition within human nucleoli. Exploration of this paradigm for chromosomal organization is complicated by the shared DNA sequence composition of five NOR-bearing acrocentric chromosome p-arms. Here, we devise a methodology for genetic manipulation of individual NORs. Efficient "scarless" genome editing of rDNA repeats is achieved on "poised" human NORs held within monochromosomal cell hybrids. Subsequent transfer to human cells introduces "active" NORs yielding readily discernible functional customized ribosomes. We reveal that ribosome biogenesis occurs entirely within constrained territories, tethered to individual NORs inside a larger nucleolus.

Comparative FISH analysis of Senna tora tandem repeats revealed insights into the chromosome dynamics in Senna

BackgroundDNA tandem repeats (TRs) are often abundant and occupy discrete regions in eukaryotic genomes. These TRs often cause or generate chromosomal rearrangements, which, in turn, drive chromosome evolution and speciation. Tracing the chromosomal distribution of TRs could therefore provide insights into the chromosome dynamics and speciation among closely related taxa. The basic chromosome number in the genus Senna is 2n = 28, but dysploid species like Senna tora have also been observed.ObjectiveTo understand the dynamics of these TRs and their impact on S. tora dysploidization.MethodsWe performed a comparative fluorescence in situ hybridization (FISH) analysis among nine closely related Senna species and compared the chromosomal distribution of these repeats from a cytotaxonomic perspective by using the ITS1-5.8S-ITS2 sequence to infer phylogenetic relationships.ResultsOf the nine S. tora TRs, two did not show any FISH signal whereas seven TRs showed similar and contrasting patterns to other Senna species. StoTR01_86, which was localized in the pericentromeric regions in all S. tora, but not at the nucleolar organizer region (NOR) site, was colocalized at the NOR site in all species except in S. siamea. StoTR02_7_tel was mostly localized at chromosome termini, but some species had an interstitial telomeric repeat in a few chromosomes. StoTR05_180 was distributed in the subtelomeric region in most species and was highly amplified in the pericentromeric region in some species. StoTR06_159 was either absent or colocalized in the NOR site in some species, and StoIGS_463, which was localized at the NOR site in S. tora, was either absent or localized at the subtelomeric or pericentromeric regions in other species.ConclusionsThese data suggest that TRs play important roles in S. tora dysploidy and suggest the involvement of 45S rDNA intergenic spacers in “carrying” repeats during genome reshuffling.

A Panicum-derived chromosomal segment captured by Hordeum a few million years ago preserves a set of stress-related genes.

Intra-specific variability is a cornerstone of evolutionary success of species. Acquiring genetic material from distant sources is an important adaptive mechanism in bacteria, but it can also play a role in eukaryotes. In this paper, we investigate the nature and evolution of a chromosomal segment of panicoid (Poaceae, Panicoideae) origin occurring in the nuclear genomes of species of the barley genus Hordeum (Pooideae). The segment, spanning over 440kb in the Asian Hordeum bogdanii and 219kb in the South American Hordeum pubiflorum, resides on a pair of nucleolar organizer region (NOR)-bearing chromosomes. Conserved synteny and micro-collinearity of the segment in both species indicate a common origin of the segment, which was acquired before the split of the respective barley lineages 5-1.7million years ago. A major part of the foreign DNA consists of several approximately 68kb long repeated blocks containing five stress-related protein-coding genes and transposable elements (TEs). Whereas outside these repeats, the locus was invaded by multiple TEs from the host genome, the repeated blocks are rather intact and appear to be preserved. The protein-coding genes remained partly functional, as indicated by conserved reading frames, a low amount of non-synonymous mutations, and expression of mRNA. A screen across Hordeum species targeting the panicoid protein-coding genes revealed the presence of the genes in all species of the section Stenostachys. In summary, our study shows that grass genomes can contain large genomic segments obtained from distantly related species. These segments usually remain undetected, but they may play an important role in the evolution and adaptation of species.

Application of histochemistry AgNORs in diagnosing benign lesion, premalignant and malignant prostate tissue

Objective: Argyrophilic nucleolar organizer regions (AgNORs) count has been suggested as an objective method in differentiating of various non neoplastic lesions of the prostate. Material and Methods: This study was done on archival paraffin block consisting of 6 cases of each, benign, premalignant, and malignant lesions of the prostate. All specimens were studied and evaluated with Haematoxylyn and Eosin followed by AgNORs histochemistry staining and its expression was determined by counting AgNORs dot per nuclei in 100 nuclei using a 100x oil immersion lens. Results: The results showed a linear increasing trend of mean mAgNOR count according to prostatic lesion (benign to malignant). However, this is not statistically significance as the p-value > 0,05 (p- value=0,516). Conclusion: Based on this study, AgNOR cannot be use to determine prostatic lesion behavior. Futher study with larger samples should be done to get significant result.