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INTRODUCTION: To faithfully distribute genetic material to daughter cells during cell division, spindle fibers must couple to DNA by means of a structure called the kinetochore, which assembles at each chromosome’s centromere. Human centromeres are located within large arrays of tandemly repeated DNA sequences known as alpha satellite (αSat), which often span millions of base pairs on each chromosome. Arrays of αSat are frequently surrounded by other types of tandem satellite repeats, which have poorly understood functions, along with nonrepetitive sequences, including transcribed genes. Previous genome sequencing efforts have been unable to generate complete assemblies of satellite-rich regions because of their scale and repetitive nature, limiting the ability to study their organization, variation, and function. RATIONALE: Pericentromeric and centromeric (peri/centromeric) satellite DNA sequences have remained almost entirely missing from the assembled human reference genome for the past 20 years. Using a complete, telomere-to-telomere (T2T) assembly of a human genome, we developed and deployed tailored computational approaches to reveal the organization and evolutionary patterns of these satellite arrays at both large and small length scales. We also performed experiments to map precisely which αSat repeats interact with kinetochore proteins. Last, we compared peri/centromeric regions among multiple individuals to understand how these sequences vary across diverse genetic backgrounds. RESULTS: Satellite repeats constitute 6.2% of the T2T-CHM13 genome assembly, with αSat representing the single largest component (2.8% of the genome). By studying the sequence relationships of αSat repeats in detail across each centromere, we found genome-wide evidence that human centromeres evolve through “layered expansions.” Specifically, distinct repetitive variants arise within each centromeric region and expand through mechanisms that resemble successive tandem duplications, whereas older flanking sequences shrink and diverge over time. We also revealed that the most recently expanded repeats within each αSat array are more likely to interact with the inner kinetochore protein Centromere Protein A (CENP-A), which coincides with regions of reduced CpG methylation. This suggests a strong relationship between local satellite repeat expansion, kinetochore positioning, and DNA hypomethylation. Furthermore, we uncovered large and unexpected structural rearrangements that affect multiple satellite repeat types, including active centromeric αSat arrays. Last, by comparing sequence information from nearly 1600 individuals’ Xchromosomes, we observed that individuals with recent African ancestry possess the greatest genetic diversity in the region surrounding the centromere, which sometimes contains a predominantly African αSat sequence variant. CONCLUSION: The genetic and epigenetic properties of centromeres are closely interwoven through evolution. These findings raise important questions about the specific molecular mechanisms responsible for the relationship between inner kinetochore proteins, DNA hypomethylation, and layered αSat expansions. Even more questions remain about the function and evolution of non-αSat repeats. To begin answering these questions, we have produced a comprehensive encyclopedia of peri/centromeric sequences in a human genome, and we demonstrated how these regions can be studied with modern genomic tools. Our work also illuminates the rich genetic variation hidden within these formerly missing regions of the genome, which may contribute to health and disease. This unexplored variation underlines the need for more T2T human genome assemblies from genetically diverse individuals.

The aim of this research is to compare the fluorescence of different trademarks of composite resins under ultraviolet light, indicating through the optical characteristics the restorative materials that best mimic the properties of dental fluorescence. In this study, nine composite resin trademarks of EA2 color were evaluated, and ten test samples were prepared for each material, totalizing ninety specimens. The specimens were produced from a bipartite aluminium matrix (10x2 mm), and then stored for 24 h in tubes of radiographic films, immersed in distilled water and after 48 h it were polished. A blind-type study (four evaluators) was used and the samples were analyzed in a dark wooden chamber where it was coupled two black lamps. In the data collection phase, the Kolmogorov-Smirnov normality test, ANOVA and Post Hoc of Tukey were used (adopting a significance level of 0.05). It was noted that the composite resin of the trademark Ultrafill was more fluorescent and Luna was statistically less fluorescent than all other materials, while Opallis and Tetric were superior to Glacier. There was no significant statistical difference among the composite resins Premissa, Point 4, Llis and Premium.

Eukaryote genomes are replete with repetitive DNAs. This class includes tandemly repeated satellite DNAs (satDNA) which are among the most abundant, fast evolving (yet poorly studied) genomic components. Here, we used high-throughput sequencing data from three cactophilic Drosophila species, D. buzzatii, D. seriema, and D. mojavensis, to access and study their whole satDNA landscape. In total, the RepeatExplorer software identified five satDNAs, three previously described (pBuM, DBC-150 and CDSTR198) and two novel ones (CDSTR138 and CDSTR130). Only pBuM is shared among all three species. The satDNA repeat length falls within only two classes, between 130 and 200 bp or between 340 and 390 bp. FISH on metaphase and polytene chromosomes revealed the presence of satDNA arrays in at least one of the following genomic compartments: centromeric, telomeric, subtelomeric, or dispersed along euchromatin. The chromosomal distribution ranges from a single chromosome to almost all chromosomes of the complement. Fiber-FISH and sequence analysis of contigs revealed interspersion between pBuM and CDSTR130 in the microchromosomes of D. mojavensis. Phylogenetic analyses showed that the pBuM satDNA underwent concerted evolution at both interspecific and intraspecific levels. Based on RNA-seq data, we found transcription activity for pBuM (in D. mojavensis) and CDSTR198 (in D. buzzatii) in all five analyzed developmental stages, most notably in pupae and adult males. Our data revealed that cactophilic Drosophila present the lowest amount of satDNAs (1.9–2.9%) within the Drosophila genus reported so far. We discuss how our findings on the satDNA location, abundance, organization, and transcription activity may be related to functional aspects.

Aim: To describe the main characteristics of the treatment techniques for oroantral communications and fistulas. Methodology: This work was accomplished from scientific articles found in the bibliographic catalogued databases PubMed, Scielo, Google Scholar and ResearchGate searcher, under the English descriptors Oroantral Fistula, Oral Fistula, Maxillary Sinus and Surgery Oral, published until the end of the first trimester of the year 2018. Results: The oroantral communications allow the passage of food, liquids, and microorganisms, causing maxillary sinusitis; the diagnosis is made from anamnesis, clinical examination and complementary imaging tests. The treatment need an approach that presents the capacity to promote closure of the communication or fistula, leading to the recovery of health and depending on the characteristics of each case, it may vary from the need to use a simpler and easier to handle flap such as vestibular flap, palatal flap rotation or a combination of these, until the need to perform a more complex as the rotation of the adipose Bichat\'s bulla. Conclusion:The professional who performs dental extractions must be able to treat these complications, otherwise he should consider referral to a specialist when, clinical and complementary examinations, the communication risk is perceived.

The 1.688 satellite DNA is present in the genome of Drosophila species from the melanogaster subgroup and has never been detected in species outside this subgroup. We investigated the presence and evolution of the 1.688 satDNA in all Drosophila genomes sequenced so far. Blast searches showed that 1.688 repeats are virtually confined to species from the melanogaster subgroup. Phylogenetic analysis of ~6,500 repeats extracted from D. melanogaster , D. simulans , D. sechellia , D. yakuba and D. erecta revealed the presence of 1.688 family on heterochromatin and euchromatin of all five species. Heterochromatic copies revealed a concerted mode of evolution and a species-specific pattern. Oppositely, euchromatic copies lack species-specific or array-specific pattern. Euchromatic arrays also showed a high number of insertions on 5Kb upstream/downstream of genes and in intronic regions. Unexpectedly, we found an array with at least three full 1.688 tandem repeats in the genome of D. willistoni . These repeats were highly similar to the ones present in the chromosome X of D. melanogaster , although both species have diverged from each other more than 35Mya, suggesting that 1.688 repeats from the X chromosome of D. melanogaster moved to D. willistoni by a recent horizontal transfer event.

Repetitive DNAs are abundant fast evolving components of eukaryotic genomes, which often possess important structural and functional roles. Despite their ubiquity, repetitive DNAs are poorly studied when compared to the genic fraction of genomes. Here, we took advantage of the availability of the sequenced genome of the common marmoset Callithrix jacchus to assess its satellite DNAs (satDNAs) and their distribution in Callitrichini. Firstly, we performed similarity-based clustering, repeat identification, and classification using RepeatExplorer with whole-genome shotgun Illumina reads from a male C. jacchus. After clustering analysis, we identified a satDNA composed by 171 bp motifs, named MarmoSAT, which composes 1.09 % of the C. jacchus genome. Multiple sequence alignments were performed using Muscle 4.0. The MEGA software version 5.05 was used for the calculation of genetic distances and construction of Neighbor-Joining (NJ) trees. Chromosome preparations were obtained from fibroblast cultures of one male of each C. penicillata, C. geoffroyi, Callimico goeldii and Mico argentatus . We performed CBG-banding and fluorescence in situ hybridization (FISH) using alpha and MarmoSAT satDNAs and telomeric sequences as probes. Finally, we investigated the transcription of MarmoSAT in several tissues of C. jacchus using the RNA-seq data generated by the Non-Human Primate Reference Transcriptome Resource. FISH on chromosomes of species from Callithrichini showed that MarmoSAT had a subtelomeric location. In addition to the common monomeric form we found that MarmoSAT was also organized in higher-order repeats of 338 bp in C. goeldii . Our phylogenetic analyses showed that MarmoSAT repeats from C. jacchus lack chromosome-specific features, suggesting exchange events among subterminal regions of non-homologous chromosomes. MarmoSAT is transcribed in several tissues of C. jacchus , with the highest transcription levels in spleen, thymus and heart. The transcription profile and subtelomeric location suggest that MarmoSAT may be involved in the regulation of telomerase and modulation of telomeric chromatin. Agencias financiadoras: CNPq, CAPES, FAPEMIG

Cactophilic Drosophila species provide a valuable model to study gene–environment interactions and ecological adaptation. Drosophila buzzatii and Drosophila mojavensis are two cactophilic species that belong to the repleta group, but have very different geographical distributions and primary host plants. To investigate the genomic basis of ecological adaptation, we sequenced the genome and developmental transcriptome of D. buzzatii and compared its gene content with that of D. mojavensis and two other noncactophilic Drosophila species in the same subgenus. The newly sequenced D. buzzatii genome (161.5 Mb) comprises 826 scaffolds (>3 kb) and contains 13,657 annotated protein-coding genes. Using RNA sequencing data of five life-stages we found expression of 15,026 genes, 80% protein-coding genes, and 20% noncoding RNA genes. In total, we detected 1,294 genes putatively under positive selection. Interestingly, among genes under positive selection in the D. mojavensis lineage, there is an excess of genes involved in metabolism of heterocyclic compounds that are abundant in Stenocereus cacti and toxic to nonresident Drosophila species. We found 117 orphan genes in the shared D. buzzatii–D. mojavensis lineage. In addition, gene duplication analysis identified lineage-specific expanded families with functional annotations associated with proteolysis, zinc ion binding, chitin binding, sensory perception, ethanol tolerance, immunity, physiology, and reproduction. In summary, we identified genetic signatures of adaptation in the shared D. buzzatii–D. mojavensis lineage, and in the two separate D. buzzatii and D. mojavensis lineages. Many of the novel lineage-specific genomic features are promising candidates for explaining the adaptation of these species to their distinct ecological niches., This work was supported by grants BFU2008-04988 and BFU2011-30476 from Ministerio de Ciencia e Innovación (Spain) to A.R., by an FPI fellowship to Y.G. and a PIF-UAB fellowship to N.R, and by the National Institute of General Medical Sciences of the National Institute of Health under award number R01GM071813 to E.B.