Julio Cesar Pieczarka

The açai fruit ( Euterpe oleracea ) is valued for bioactive properties beyond nutrition, with its seed typically discarded as waste. This study evaluated ethanolic extracts from black (BA) and white (WA) açai seeds for antioxidant, cytotoxic, cytoprotective, and genotoxic activities in vitro. Using DPPH, MTT, and micronucleus assays on normal (MNP01) and gastric adenocarcinoma (ACP02) cell lines, both extracts showed antioxidant activity (BA ∼30% more effective than WA). Neither cytotoxic nor genotoxic effects were observed, but both exhibited cytoprotective properties in short‐term assays. In clonogenic assays, BA (200 µg/mL) inhibited colony formation in both lines but did not interfere with cisplatin's efficacy. The findings suggest açai seed extracts offer transient cytoprotection, likely due to phenolic content and free radical scavenging, warranting further study for potential therapeutic applications.

The order Passeriformes, the most speciose avian order, includes over 6000 species (~60% of all birds). The Amazon Basin alone hosts > 900 bird species, with Passeriformes representing > 500 of them. The family Thamnophilidae comprises ~200 insectivorous species, accounting for 15% of Neotropical passerine richness. Within Thamnophilinae, Isleria is the least speciose genus, containing only two species. It was erected after phylogenetic analyses revealed Myrmotherula as non‐monophyletic. To advance knowledge of chromosomal evolution in Passeriformes, we analyzed the karyotype of Isleria hauxwelli using molecular cytogenetics. We found a diploid number of 2n = 84 and a fundamental number (FN) of 92. The BOE‐7 probe, corresponding to the ancestral fusion of GGA‐9 with two microchromosomes, maintained that configuration without undergoing fission to produce IHA‐5. The BOE‐14 probe, typically fragmented in all cytogenomically characterized Passeriformes, corresponded to two distinct GGA segments: the R3 portion and a region of unknown homology. This is the first documentation of such chromosomal organization in passerines. The absence of these fissions suggests a possible autapomorphic chromosomal condition within Thamnophilidae. Additionally, a potential fission involving microchromosomes homeologous to probes BOE‐15 and BOE‐16 is suggested: while these probes mark three microchromosome pairs in GGA, they mark four pairs in I. hauxwelli —a feature not yet observed in other passerines. As most Thamnophilidae remain cytogenetically uncharacterized, systematic study of this family is essential to determine whether these rearrangements represent synapomorphies, autapomorphies, or convergent events.

The typical antbirds (Passeriformes, Thamnophilidae) are a monophyletic group comprising 225 species in 45 genera, primarily distributed in the lowland forests of the Neotropics. There is limited karyotypic information for this bird family, including chromosome morphology and diploid number (2n), highlighting the importance of understanding the evolutionary history of karyotypic diversification of this family. Few species in Thamnophilidae have been karyotyped to date, with observed diploid numbers ranging from 76 to 82 chromosomes. This study examined the karyotype of three Thamnophilidae species using chromosome painting: Phlegopsis nigromaculata , Thamnophilus aethiops , a nd Pyriglena leuconota . Whole chromosome probes from Burhinus oedicnemus (BOE) and Gallus gallus (GGA) were used, and results were compared with existing data. Additionally, three more species ( Myrmotherula longipennis , Myrmoborus myotherinus , and Thamnomanes caesius ) were analyzed using G-banding and/or Giemsa staining. All karyotypes aligned with the standard Aves and Passeriformes karyotype, displaying high diploid numbers (2n = 80 in Pyriglena leuconota, 2n = 82 in Thamnophilus aethiops , and 2n = 86 in Phlegopsis nigromaculata ), few macrochromosomes, and numerous microchromosome pairs. Furthermore, our analysis with GGA probes in Thamnophilidae species corroborates the data observed in other Passeriformes families, indicating that the centric fission of GGA2 is a characteristic of Suboscines. Based on this result, we propose an ancestral karyotype for Suboscines that features the fission of GGA-2, which may offer a more robust explanation for the karyotypic diversity found among birds of the order Passeriformes.

Interstitial telomeric sequences (ITSs) can occur at interstitial sites within chromosomes because of chromosomal rearrangements, DNA repair mechanisms, or as part of satellite DNA. This study examines ITSs in the karyotype of the scorpion Opisthacanthus cayaporum and their behaviour during meiotic prophase I. The karyotype of this species is 2n = 50 (6 submetacentric + 44 acrocentric), with ten acrocentric chromosome pairs and pair 2 (submetacentric) having interstitial telomeric sequences associated with the pericentromeric region. Immuno-FISH analyses of cells in prophase I indicated that synapsis starts during zygotene, without a telomeric bouquet configuration; premeiotic cells showed bouquet-like telomeric clustering. In early pachytene, telomeric DNA bridges-particularly between ITSs-were observed connecting some non-homologous chromosome pairs. Foci of the DNA repair protein RAD51 were present from late leptotene to mid-pachytene, mainly at interstitial sites of homologous chromosomes. The data indicate that in O. cayaporum, ITS sites are heterochromatic and may aid in the alignment of homologs during prophase I, contributing to the segregation of achiasmatic chromosomes in O. cayaporum.

Rhamphichthys (Gymnotiformes), a genus with uncertain taxonomy due to rarity and morphological similarity, exhibits greater diversity in the Amazon Basin. Phylogenetic analysis of COI data from specimens collected in the Amazon Basin, in Guamá River (Belém and Barcarena), Caripetuba River, and Anequara River (Abaetetuba) and deposited in the collection of the Museu Paraense Emílio Goeldi identified two major monophyletic clades within Rhamphichthys, encompassing R. pantherinus and R. rostratus. Cytogenetic analysis of 24 specimens, both with 2n=50 but differing fundamental number (FN) and karyotype formula (KF), enabled their differentiation. Although 2n=50 is likely ancestral, karyotype constitution varies among species. By combining cytogenetic and molecular data, we reclassified the previously described Rhamphichthys “marmoratus” (2n=50, FN=94, KF=44m/sm+6st/a) as R. heleios, and previous R. rostratus (2n=50, FN=92, KF=42m/sm+8st/a) as R. pantherinus. This study provides the first cytogenetic data for the real R. rostratus species and reports novel B chromosomes within the Rhamphichthyidae family.

Cytogenetic studies provide valuable insights into the evolutionary dynamics of fish genomes, particularly in groups with high species diversity and ecological relevance. Among Neotropical cichlids, chromosomal data have revealed both conservation patterns and significant structural variations, reflecting intense karyotypic diversification. In this context, mapping repetitive DNA sequences has proven useful in aiding understanding of genomic organization and chromosomal evolution. However, information remains scarce for several cichlid genera. The present study investigated the chromosomal distribution of repetitive sequences, such as 18S and 5S ribosomal genes, as well as telomeric sequences, in three Amazonian species of Lugubria: L. cincta, L. strigata, and L. lugubris. The results revealed a diploid number of 2n = 48, along with variations in the karyotypic formula among the species. Mapping of repetitive sequences revealed distinct patterns of 18S rDNA distribution, with clusters located on different chromosome pairs. Conversely, the 5S rDNA showed a conserved position on a subtelocentric/acrocentric pair in all three species. Furthermore, the presence of interstitial telomeric sequences in L. cincta and L. strigata indicates greater genomic plasticity in these species, suggesting more pronounced chromosome dynamics in the genus Lugubria. These data contribute to the understanding of chromosomal evolution and diversification in this diverse group of Neotropical cichlids and may aid in future cytotaxonomic studies.

Techniques such as whole chromosome painting (WCP) have effectively expanded our understanding of the evolution and organization of the genome in fish, allowing us to obtain more detailed information about several evolutionary questions. The genus Gymnotus is the most cytogenetically studied among the Gymnotiformes, having a significant karyotypic diversity. Molecular cytogenetic studies in the genus Gymnotus show a dynamic reorganization in the karyotype, in addition to the presence of different sex chromosome systems. In this study, with whole chromosome probes from the karyotype of Gymnotus carapo orientalis sensu stricto cytotype 2n = 42, we analyzed the karyotype of Gymnotus mamiraua 2n = 54, from two localities, and compared with previous studies, to obtain a better understanding of the homologies and chromosomal differences among the species of this genus. The results shows both populations with no difference detected by chromosome painting, and overall, a larger number of signals were observed with the fluorescent probes, since GMA has a higher diploid number. Using chromosomal painting on a greater number of species will make it possible to construct a map of homologies between them that will help define the phylogeny of the group.

In Brazil, bat species that use caves as shelters are constantly susceptible to anthropic impacts. Of the 181 species of bats in Brazil, 81 are recorded in caves, 13 of which are considered essentially cave dwellers. The Carajás National Forest Conservation Unit, located in the southeastern region of Pará, serves as a refuge for these species, among others. The present work sought to reveal the chromosomal diversity of bats in six caves of the Carajás National Forest. Cytogenetic analyses were carried out for some species as an additional tool for taxonomic identification. We present here the conventional karyotype of eight species, five being described for the first time in Brazilian specimens. We also described for the first time the karyotypes of Natalus macrourus and Peropteryx kappleri. These findings may be helpful to support conservation guidelines, and for the knowledge of these species' biodiversity, evolutionary history, and to support genome sequencing efforts.

Oecomys (Rodentia, Sigmodontinae, Oryzomyini) is a taxonomically complex and cytogenetically diverse genus with a controversial intraspecific phylogenetic relationship. Karyotypic analyses, using whole chromosome probes from Hylaeamys megacephalus (HME, Sigmodontinae, Oryzomyini) in some taxonomic lineages of this genus have detected the rearrangements that shaped their karyotypes, in addition to revealing relevant insights into the taxonomic status of these taxa. Thus, to investigate the chromosomal evolution of the genus, we characterized the karyotype of Oecomys rutilus (ORU) with HME probes, establishing chromosomal homology maps with the karyotypes of other congeners. The chromosomal phylogeny obtained by Maximum Parsimony analysis recovered the genus Oecomys as monophyletic, with moderate bootstrap support (68%). This clade branches into two large groups, the first including O. rutilus followed by O. catherinae—Rio de Janeiro and O. catherinae—Pará; the other group includes O. auyantepui followed by O. paricola cytotype C and O. paricola cytotype A + cytotype B. We detected that these taxa underwent intensive reorganization of their karyotypes, the rearrangements producing this diversity were 15 pericentric inversions, 12 centric fusions, 11 fissions, 5 in tandem fusions, 8 translocations and the addition/deletion of constitutive heterochromatin on two autosomes and the X chromosomes. However, despite the high number of chromosomal rearrangements found, we identified some entirely conserved syntenic blocks shared among all species analyzed. From these data, we hypothesized a putative ancestral karyotype. We also detected exclusive characteristics for ORU, the syntenic blocks HME 1/20/4 (ORU 1), HME (16,17)/3 (ORU 2), HME 2/1 (ORU 4), HME 2/7 (ORU 5), HME 5/(9,10)/8 (ORU 3), HME 19/12 (ORU 9). We provide an overview of the chromosomal reorganization of the genus that points to a high chromosomal diversity and show that chromosomal rearrangements play an important role in the radiation of these species.

The distribution of Platyrrhinus guianensis , a species originally considered endemic to the Guiana subregion, has recently been extended to a southernmost Brazilian Amazon point, yet included within the Guiana Shield. Based on comprehensive revisionary work, we extend this species occurrence eastwards and southwards, encompassing 11 localities, including Eastern Amazonia forests. These records correspond to primary and secondary floodplain forest habitats in the Brazilian states of Amapá, Maranhão, Mato Grosso, and Pará.