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1.
Curr Microbiol ; 77(9): 2300-2306, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32494882

RESUMO

Acinetobacter baumannii is an emerging pathogen associated with nosocomial infections and multidrug resistance. Polymyxin B has been used to treat infections caused by multidrug-resistant (MDR) A. baumannii but an increase in polymyxin B resistance has been observed. We aimed to determine the diversity, antimicrobial susceptibility, presence of polymyxin B heteroresistance and adaptive resistance in 72 A. baumannii clinical isolates from two public hospitals in Rio de Janeiro. The isolates were identified by sequencing of rpoB gene. Determination of the genetic diversity of isolates was performed by pulsed-field gel electrophoresis and oxacillinases genes were detected by polymerase chain reaction. The polymyxin B heteroresistance was analyzed by population analysis profile and adaptive resistance was evaluated after serial daily passages of isolates in broth containing increasing polymyxin B concentrations. The results showed that 49% of the isolates were collected from respiratory system and 62% were MDR, while 35% were extensively drug resistant. Additionally, all the isolates carried blaOXA-23-like, blaOXA-51-like genes and ISAba1, while 1% had blaOXA-24-like gene. The association of ISAba1-blaOXA-23 was found in 96% of the isolates. Polymyxin B heteroresistance was found in 36% of the isolates and polymyxin B adaptive resistance was not found in the isolates. Our study demonstrated the high resistance to antimicrobials used in clinical practice and the spread of oxacillinases genes and insertion sequence (IS). We also reported the presence of heteroresistance to polymyxin B used as a last-resort therapy for MDR A. baumannii.


Assuntos
Infecções por Acinetobacter , Acinetobacter baumannii , Preparações Farmacêuticas , Acinetobacter baumannii/genética , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Brasil , Farmacorresistência Bacteriana Múltipla/genética , Humanos , Testes de Sensibilidade Microbiana , Polimixina B/farmacologia , beta-Lactamases
2.
Chromosome Res ; 25(3-4): 313-325, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28916913

RESUMO

Despite their ubiquitous incidence, little is known about the chromosomal distribution of long interspersed elements (LINEs) in mammalian genomes. Phyllostomid bats, characterized by lineages with distinct trends of chromosomal evolution coupled with remarkable ecological and taxonomic diversity, represent good models to understand how these repetitive sequences contribute to the evolution of genome architecture and its link to lineage diversification. To test the hypothesis that LINE-1 sequences were important modifiers of bat genome architecture, we characterized the distribution of LINE-1-derived sequences on genomes of 13 phyllostomid species within a phylogenetic framework. We found massive accumulation of LINE-1 elements in the centromeres of most species: a rare phenomenon on mammalian genomes. We hypothesize that expansion of these elements has occurred early in the radiation of phyllostomids and recurred episodically. LINE-1 expansions on centromeric heterochromatin probably spurred chromosomal change before the radiation of phyllostomids into the extant 11 subfamilies and contributed to the high degree of karyotypic variation observed among different lineages. Understanding centromere architecture in a variety of taxa promises to explain how lineage-specific changes on centromere structure can contribute to karyotypic diversity while not disrupting functional constraints for proper cell division.


Assuntos
Centrômero/genética , Quirópteros/genética , Cromossomos de Mamíferos , Evolução Molecular , Elementos Nucleotídeos Longos e Dispersos , Animais , Heterocromatina , Hibridização in Situ Fluorescente , Cariótipo , Filogenia , Sequências Repetitivas de Ácido Nucleico , Retroelementos , Análise de Sequência de DNA
3.
Genetica ; 142(1): 49-58, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24368540

RESUMO

Chromosomal organization and the evolution of genome architecture can be investigated by physical mapping of the genes for 45S and 5S ribosomal DNAs (rDNAs) and by the analysis of telomeric sequences. We studied 12 species of bats belonging to four subfamilies of the family Phyllostomidae in order to correlate patterns of distribution of heterochromatin and the multigene families for rDNA. The number of clusters for 45S gene ranged from one to three pairs, with exclusively location in autosomes, except for Carollia perspicillata that had in X chromosome. The 5S gene all the species studied had only one site located on an autosomal pair. In no species the 45S and 5S genes collocated. The fluorescence in situ hybridization (FISH) probe for telomeric sequences revealed fluorescence on all telomeres in all species, except in Carollia perspicillata. Non-telomeric sites in the pericentromeric region of the chromosomes were observed in most species, ranged from one to 12 pairs. Most interstitial telomeric sequences were coincident with heterochromatic regions. The results obtained in the present work indicate that different evolutionary mechanisms are acting in Phyllostomidae genome architecture, as well as the occurrence of Robertsonian fusion during the chromosomal evolution of bats without a loss of telomeric sequences. These data contribute to understanding the organization of multigene families and telomeric sequences on bat genome as well as the chromosomal evolutionary history of Phyllostomidae bats.


Assuntos
Quirópteros/genética , DNA Ribossômico/genética , Heterocromatina , Sequências Repetitivas de Ácido Nucleico , Telômero , Animais , Centrômero , Quirópteros/classificação , Cromossomos de Mamíferos , Evolução Molecular , Hibridização in Situ Fluorescente , Família Multigênica , Filogenia
4.
Genet Mol Biol ; 36(3): 336-40, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24130439

RESUMO

In this study, two species of Romaleidae grasshoppers, Radacridium mariajoseae and R.nordestinum, were analyzed after CMA3/DA/DAPI sequential staining and fluorescence in situ hybridization (FISH) to determine the location of the 18S and 5S rDNA and histone H4 genes. Both species presented karyotypes composed of 2n = 23, X0 with exclusively acrocentric chromosomes. CMA3 (+) blocks were detected after CMA3/DA/DAPI staining in only one medium size autosome bivalent and in the X chromosome in R. mariajoseae. On the other hand, all chromosomes, except the L1 bivalent, of R. nordestinum presented CMA3 (+) blocks. FISH analysis showed that the 18S genes are restricted to the X chromosome in R. mariajoseae, whereas these genes were located in the L2, S9 and S10 autosomes in R. nordestinum. In R. mariajoseae, the 5S rDNA sites were localized in the in L1 and L2 bivalents and in the X chromosome. In R. nordestinum, the 5S genes were located in the L2, L3, M4 and M5 pairs. In both species the histone H4 genes were present in a medium size bivalent. Together, these data evidence a great variability of chromosome markers and show that the 18S and 5S ribosomal genes are dispersed in the Radacridium genome without a significant correlation.

5.
Genet Mol Biol ; 36(3): 341-6, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24130440

RESUMO

The genus Phanaeus is included in the tribe Phanaeini, one of the most diverse tribes within the subfamily Scarabaeinae in terms of chromosomal characteristics. However, so far the species of this genus were not studied with differential cytogenetic techniques, limiting any inference of the probable mechanisms responsible for this diversity. In this work, several techniques were applied with the aim of cytogenetically characterizing two Phanaeus species. The karyotype found for Phanaeus (Notiophanaeus) chalcomelas was 2n = 12, neo-XY, and that of P. (N.) splendidulus was 2n = 20, Xyp, considered primitive for the family Scarabaeidae. The chromosomes of both species showed a high amount of constitutive heterochromatin (CH), with blocks rich in base pairs GC (CMA3 (+)). Moreover, in P. (N.) chalcomelas the marks revealed by C-banding and fluorochrome staining were different in size, showing CH variability. Sites of 18S ribosomal DNA (rDNA) were identified in one autosomal pair of P. (N.) chalcomelas and in five autosomal pairs of P. (N.) splendidulus. On the other hand, only one autosomal pair exhibited 5S rDNA sequences in these species. The results suggest that the karyotype differentiation of the Phanaeus species studied here involved pericentric inversions and centric fusions, as well as mechanisms related to amplification and dispersion of CH and rDNA sequences.

6.
Scand J Infect Dis ; 43(9): 742-6, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21671824

RESUMO

Group B Streptococcus (GBS) is a leading cause of infectious morbidity in newborns. We describe the prevalence of GBS colonization and the serotypes and antibiotic susceptibility profiles of isolates obtained from a cohort of human immunodeficiency virus (HIV)-infected pregnant women. This was a cross-sectional study at a centre for the prevention of mother-to-child transmission of HIV. Vaginal and rectal swabs were collected at 35-37 weeks of gestation from 158 eligible women. GBS isolates were serotyped and antimicrobial susceptibility tests performed. Patient sociodemographic characteristics, CD4 counts and viral loads were abstracted from records. The overall anogenital prevalence of GBS colonization was 49/158 (31.0%): 40/158 (25.3%) for vagina, 19/158 (12.0%) for rectum and 10/158 (6.3%) for both. Predominant serotypes were Ib (34.9%) and Ia (25.6%). All were penicillin-susceptible. Two were resistant to erythromycin (4.0%) and one to clindamycin (2.0%). The colonization rate by GBS was high in this cohort. Serotype Ib was the most frequently identified.


Assuntos
Infecções por HIV/complicações , Complicações Infecciosas na Gravidez/microbiologia , Infecções Estreptocócicas/complicações , Infecções Estreptocócicas/microbiologia , Streptococcus agalactiae/efeitos dos fármacos , Adulto , Antibacterianos/farmacologia , Contagem de Linfócito CD4 , Clindamicina/farmacologia , Estudos Transversais , Farmacorresistência Bacteriana , Eritromicina/farmacologia , Feminino , Humanos , Lactente , Recém-Nascido , Testes de Sensibilidade Microbiana , Penicilinas/farmacologia , Gravidez , Complicações Infecciosas na Gravidez/epidemiologia , Prevalência , Reto/microbiologia , Sorotipagem , Infecções Estreptocócicas/epidemiologia , Streptococcus agalactiae/isolamento & purificação , Vagina/microbiologia , Carga Viral
7.
Genetica ; 138(2): 191-5, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19757096

RESUMO

The most intriguing karyotypic variation in the Coleoptera involves variation in sex chromosome structure, origin and behavior. In this report we describe chromosomal characteristics of Deltochilum (Calhyboma) verruciferum (Coleoptera, Scarabaeidae) using conventional and differential cytogenetic techniques, with emphasis on the description of a rare sex bivalent in the Coleoptera and dispersion of repetitive DNA. This species shows 2n = 20,XY(p) with biarmed chromosomes. Analysis of constitutive heterochromatin through C-banding revealed mainly diphasic autosomes with short heterochromatic arms, while the X was completely heterochromatic and the Y was heterochromatic in the long arm. This pattern was confirmed through the use of CMA(3) fluorochrome that stained all heterochromatic regions. Silver nitrate staining marked all heterochromatic regions and the lumen of the sex bivalent in metaphase I. These results indicated that karyotypic differentiation in D. (C.) verruciferum involved autosomal amplification and dispersion of repetitive DNA and the origin of unusual sex chromosomes (XY(p)), generating a unique karyotype in this species.


Assuntos
Besouros/genética , Sequências Repetitivas de Ácido Nucleico/genética , Cromossomos Sexuais , Animais , Besouros/citologia , Besouros/metabolismo , Heterocromatina/metabolismo , Masculino , Meiose/genética , Técnicas de Amplificação de Ácido Nucleico , Aberrações dos Cromossomos Sexuais
8.
Braz J Microbiol ; 51(2): 657-664, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32180159

RESUMO

Acinetobacter baumannii has been associated with antimicrobial resistance and ability to form biofilms. Furthermore, its adherence to host cells is an important factor to the colonization process. Therefore, this study intended to identify some virulence factors that can explain the success of A. baumannii in causing nosocomial infections. We studied 92 A. baumannii isolates collected from hospitals in Rio de Janeiro, Brazil. Isolates were identified and the susceptibility to antimicrobials was determined. Oxacilinase type ß-lactamase encoding genes were amplified by polymerase chain reaction, and genetic diversity was investigated by pulsed-field gel electrophoresis (PFGE). In addition, biofilm formation on polystyrene plates using crystal violet staining was quantified, and adherence to human cell lines was evaluated. Eighty-six isolates were multidrug-resistant, of which 93% were carbapenem-resistant. All isolates had the blaOXA-51 gene and 94% had the blaOXA-23 gene, other searched blaOXA genes were not detected. PFGE typing showed two predominant clones, and biofilm production was observed in 79% of isolates. A. baumannii isolates adhered better to HEp-2 cell compared with A-549 cell. Clones A, B, E, and F showed a significantly increased adherence to HEp-2 compared with adherence to A-549 cell. Our findings revealed that A. baumannii isolates had high frequencies of resistance to antimicrobial agents, ability to form biofilm, and capacity to adhere to HEp-2 cells.


Assuntos
Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/fisiologia , Aderência Bacteriana , Farmacorresistência Bacteriana Múltipla , Células Epiteliais/microbiologia , Células A549 , Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/enzimologia , Acinetobacter baumannii/genética , Antibacterianos/farmacologia , Biofilmes , Carbapenêmicos/farmacologia , Variação Genética , Humanos , Testes de Sensibilidade Microbiana , beta-Lactamases/genética
9.
Genet Mol Biol ; 32(2): 276-80, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21637680

RESUMO

Meiotic and mitotic chromosomes of Dichotomius nisus, D. semisquamosus and D. sericeus were analyzed after conventional staining, C-banding and silver nitrate staining. In addition, Dichotomius nisus and D. semisquamosus chromosomes were also analyzed after fluorescent in situ hybridization (FISH) with an rDNA probe. The species analyzed had an asymmetrical karyotype with 2n = 18 and meta-submetacentric chromosomes. The sex determination mechanism was of the Xy(p) type in D. nisus and D. semisquamosus and of the Xy (r) type in D. sericeus. C-banding revealed the presence of pericentromeric blocks of constitutive heterochromatin (CH) in all the chromosomes of the three species. After silver staining, the nucleolar organizer regions (NORs) were located in autosomes of D. semisquamosus and D. sericeus and in the sexual bivalent of D. nisus. FISH with an rDNA probe confirmed NORs location in D. semisquamosus and in D. nisus. Our results suggest that chromosome inversions and fusions occurred during the evolution of the group.

10.
Mol Cytogenet ; 6(1): 41, 2013 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-24090216

RESUMO

BACKGROUND: Grasshoppers from the Romaleidae family are well distributed in the Neotropical Region and represent a diversified and multicolored group in which the karyotype is conserved. Few studies have been conducted to understand the evolutionary dynamics of multigene families. Here, we report the chromosomal locations of the 18S and 5S rDNA and H3 histone multigene families in four grasshopper species from the Romaleidae family, revealed by fluorescent in situ hybridization (FISH). RESULTS: The 5S rDNA gene was located in one or two chromosome pairs, depending on the species, and was found in a basal distribution pattern. Its chromosomal location was highly conserved among these species. The 18S rDNA was located in a single medium-sized chromosomal pair in all species analyzed. Its chromosomal location was near the centromere in the proximal or pericentromeric regions. The location of the H3 histone gene was highly conserved, with slight chromosomal location differences among some species. To our knowledge, this is the first report of a megameric chromosome carrying both the chromosomal markers 18S rDNA and the H3 histone genes, thereby expanding our understanding of such chromosomes. CONCLUSIONS: The 5S and 18S rDNA genes and the H3 histone genes showed a conservative pattern in the species that we analyzed. A basal distribution pattern for 5S rDNA was observed with a location on the fourth chromosomal pair, and it was identified as the possible ancestral bearer. The 18S rDNA and H3 histone genes were restricted to a single pair of chromosomes, representing an ancestral pattern. Our results reinforce the known taxonomic relationships between Chromacris and Xestotrachelus, which are two close genera.

11.
Comp Cytogenet ; 6(1): 17-28, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-24260649

RESUMO

The genus Artibeus represents a highly diverse group of bats from the Neotropical region, with four large species occurring in Brazil. In this paper, a comparative cytogenetic study was carried out on the species Artibeus obscurus Schinz, 1821, Artibeus fimbriatus Gray, 1838, Artibeus lituratus Olfers, 1818 and Artibeus planirostris Spix, 1823 that live sympatrically in the northeast of Brazil, through C-banding, silver staining and DNA-specific fluorochromes (CMA3 and DAPI). All the species had karyotypes with 2n=30,XX and 2n=31,XY1Y2, and FN=56. C-banding showed constitutive heterochromatin (CH) blocks in the pericentromeric regions of all the chromosomes and small CH blocks at the terminal region of pairs 5, 6, and 7 for all species. Notably, our C-banding data revealed species-specific autosomic CH blocks for each taxon, as well as different heterochromatic constitution of Y2 chromosomes of Artibeus planirostris. Ag-NORs were observed in the short arms of chromosomes 5, 6 and 7 in all species. The sequential staining AgNO3/CMA3/DA/DAPI indicated a positive association of CH with Ag-NORs and positive CMA3 signals, thus reflecting GC-richness in these regions in Artibeus obscurus and Artibeus fimbriatus. In this work it was possible to identify interespecific divergences in the Brazilian large Artibeus species using C-banding it was possible provided a suitable tool in the cytotaxonomic differentiation of this genus.

12.
Genet Mol Biol ; 34(2): 214-9, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21734819

RESUMO

The grasshopper species Orthoscapheus rufipes and Eujivarus fusiformis were analyzed using several cytogenetic techniques. The karyotype of O. rufipes, described here for the first time, had a diploid number of 2n = 23, whereas E. fusiformis had a karyotype with 2n = 21. The two species showed the same mechanism of sex determination (XO type) but differed in chromosome morphology. Pericentromeric blocks of constitutive heterochromatin (CH) were detected in the chromosome complement of both species. CMA(3)/DA/DAPI staining revealed CMA(3)-positive blocks in CH regions in four autosomal bivalents of O. rufipes and in two of E. fusiformis. The location of active NORs differed between the two species, occurring in bivalents M(6) and S(9) of O. rufipes and M(6) and M(7) of E. fusiformsi. The rDNA sites revealed by FISH coincided with the number and position of the active NORs detected by AgNO(3) staining. The variability in chromosomal markers accounted for the karyotype differentiation observed in the tribe Abracrini.

14.
Micron ; 41(8): 960-5, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20675144

RESUMO

The Coleopterans of Scarabaeinae clade presents Coprophanaeus (Megaphanaeus) ensifer and C. (Coprophanaeus) cyanescens (Scarabaeidae) when they are studied cytogenetically by different techniques. The species present symmetric karyotypes, diploid number of 2n=20, and meta-submetacentric chromosomes. C. (M.) ensifer present an XY sex-determining mechanism and C. (C.) cyanescens an XY(p) parachute mechanism. Analysis of constitutive heterochromatin (CH) in the two species revealed the presence of diphasic autosomes, with log arm heterochromatics. Moreover, an additional heterochromatic block in four autosomal bivalents were observed in C. (M.) ensifer. CMA(3)/DA/DAPI fluorochrome staining detected CMA(3) positive heterochromatic blocks restricted to the sex chromosomes in C. (C.) cyanescens, whereas in C. (M.) ensifer CMA(3) positive pericentromeric blocks were present in all autosomes, in the Y chromosome and in the four additional heterochromatic blocks. DAPI staining was neutral in both species. Silver nitrate (AgNO(3)) staining was inefficient for the detection of the nucleolar organizer region (NORs), but showed affinity for the heterochromatic regions. Fluorescence in situ hybridization (FISH) revealed the presence of 45S rDNA sites in the terminal region of the three autosomal bivalents of C. (C.) cyanescens and in seven bivalents and the Y chromosome of C. (M.) ensifer. These results contribute to a better understanding of chromosome evolution in the genus Coprophanaeus, and demonstrate a wide CH variability and the largest number of ribosomal sites among Coleoptera.


Assuntos
Besouros/citologia , Análise Citogenética , Heterocromatina , RNA Ribossômico/genética , Animais , Cromossomos de Insetos , Diploide , Hibridização in Situ Fluorescente , Cariotipagem , Masculino , Microscopia de Fluorescência
15.
Genet Mol Biol ; 32(4): 748-52, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21637449

RESUMO

Phyllostomidae comprises the most diverse family of neotropical bats, its wide range of morphological features leading to uncertainty regarding phylogenetic relationships. Seeing that cytogenetics is one of the fields capable of providing support for currently adopted classifications through the use of several markers, a comparative analysis between two Phyllostomidae species was undertaken in the present study, with a view to supplying datasets for the further establishment of Phyllostomidae evolutionary relationships. Karyotypes of Lonchorhina aurita (2n = 32; FN = 60) and Trachops cirrhosus (2n = 30; FN = 56) were analyzed by G- and C-banding, silver nitrate staining (Ag-NOR) and base-specific fluorochromes. Chromosomal data obtained for both species are in agreement with those previously described, except for X chromosome morphology in T. cirrhosus, hence indicating chromosomal geographical variation in this species. A comparison of G-banding permitted the identification of homeologies in nearly all the chromosomes. Furthermore, C-banding and Ag-NOR patterns were comparable to what has already been observed in the family. In both species CMA(3) /DA/DAPI staining revealed an R-banding-like pattern with CMA (3) , whereas DAPI showed uniform staining in all the chromosomes. Fluorochrome staining patterns for pericentromeric constitutive heterochromatin (CH) regions, as well as for nucleolar organizing regions (NORs), indicated heterogeneity regarding these sequences among Phyllostomidae species.

16.
Genetica ; 132(1): 95-101, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17486415

RESUMO

We report here, for the first time, the chromosome complement, number and location of the nucleolar organizer regions (NORs) revealed by silver staining (AgNO(3)) and fluorescent in situ hybridization (FISH) in five Neotropical gomphocerine species: Rhammatocerus brasiliensis, R. brunneri, R. palustris, R. pictus and Amblytropidia sp. The objective of this study was to summarize available data and propose a model of chromosome evolution in Neotropical gomphocerines. All five species studied showed chromosome numbers consisting of 2n = 23,X0 in males and 2n = 24,XX in females. Amblytropidia sp. was the only species showing a bivalent (M(8)) with megameric behavior during meiosis. The rDNA sites were restricted to autosomal pairs, i.e. the pericentromeric region of the S(9) chromosome, the consensus NOR location in all five species. R. brasiliensis was the only species showing additional NORs on M(4) and M(6) pairs which, likewise the S(9) NOR, were active in all cells analyzed. Comparison of these results with those reported previously in Palearctic gomphocerine species suggests higher resemblance of Neotropical species with the Old World species also possessing 23/24 chromosomes. Evolutionary mechanisms responsible for the observed interspecific variation in NOR location in this group are discussed.


Assuntos
DNA Ribossômico/análise , Evolução Molecular , Gafanhotos/genética , Região Organizadora do Nucléolo/ultraestrutura , Animais , Cromossomos/química , Cromossomos/ultraestrutura , Feminino , Gafanhotos/química , Hibridização in Situ Fluorescente , Cariotipagem , Masculino , Região Organizadora do Nucléolo/química , Coloração pela Prata
17.
Mol Ecol ; 15(2): 433-47, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16448411

RESUMO

Abstract The three living species of manatees, West Indian (Trichechus manatus), Amazonian (Trichechus inunguis) and West African (Trichechus senegalensis), are distributed across the shallow tropical and subtropical waters of America and the western coast of Africa. We have sequenced the mitochondrial DNA control region in 330 Trichechus to compare their phylogeographic patterns. In T. manatus we observed a marked population structure with the identification of three haplotype clusters showing a distinct spatial distribution. A geographic barrier represented by the continuity of the Lesser Antilles to Trinidad Island, near the mouth of the Orinoco River in Venezuela, appears to have restricted the gene flow historically in T. manatus. However, for T. inunguis we observed a single expanding population cluster, with a high diversity of very closely related haplotypes. A marked geographic population structure is likely present in T. senegalensis with at least two distinct clusters. Phylogenetic analyses with the mtDNA cytochrome b gene suggest a clade of the marine Trichechus species, with T. inunguis as the most basal trichechid. This is in agreement with previous morphological analyses. Mitochondrial DNA, autosomal microsatellites and cytogenetic analyses revealed the presence of hybrids between the T. manatus and T. inunguis species at the mouth of the Amazon River in Brazil, extending to the Guyanas and probably as far as the mouth of the Orinoco River. Future conservation strategies should consider the distinct population structure of manatee species, as well as the historical barriers to gene flow and the likely occurrence of interspecific hybridization.


Assuntos
Variação Genética , Genética Populacional , Hibridização Genética , Filogenia , Trichechus/genética , Animais , Conservação dos Recursos Naturais , DNA Mitocondrial , Repetições de Microssatélites , Especificidade da Espécie
18.
Genetica ; 125(2-3): 253-60, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16247697

RESUMO

The chromosomes of Chromacris nuptialis and C. speciosa were comparatively analyzed using different cytogenetic techniques, in order to determine the level of karyotypic similarities and differences between the species. The results show similarities in chromosome number (2n=23,X0) and acrocentric morphology. In some C. nuptialis individuals meiotic irregularities were detected involving the L(2) bivalent. This bivalent was delayed and presented anaphasic bridges and other aberrations. Differences in constitutive heterochromatin (CH) patterns and composition were observed through C-banding and fluorochromes staining. Silver nitrate staining revealed a single medium nucleolar organizer regions (NORs) pair, per species. Differences were also observed in NORs location, which was pericentromeric in C. nuptialis and proximal in C. speciosa. FISH using an rDNA probe confirmed the existence of ribosomal sites coinciding with active regions visualized by silver nitrate. The possible implications of the karyotype differences observed between both species are discussed.


Assuntos
Gafanhotos/genética , Animais , Bandeamento Cromossômico , Cromossomos/genética , Citogenética , DNA Ribossômico/genética , Feminino , Variação Genética , Gafanhotos/classificação , Heterocromatina/genética , Hibridização in Situ Fluorescente , Cariotipagem , Masculino , Especificidade da Espécie
19.
Hereditas ; 138(2): 94-100, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12921160

RESUMO

The karyotypes of the bat species Molossus ater, M. molossus (2n = 48; NF = 64) and Molossops planirostris (2n = 34; NF = 60) were analyzed by G-, C-banding, silver nitrate staining (AgNO3), base-specific fluorochromes and fluorescent in situ hybridization (FISH). The two species of Molossus presented the constitutive heterochromatin (CH) in the pericentromeric regions of all autosomes and in the X chromosome, while the Y chromosome was completely heterochromatic. Molossops planirostris showed conspicuous CH blocks in the pericentromeric regions of the pairs 4, 5, 8, 15, 16 and in the short arm of the X chromosome, while the Y did not present any CH block. Pretreated slides for C-banding stained with DAPI (CB-DAPI) revealed a similar pattern of C-banding (CBG) for these species. Sequential staining (AgNO3/CMA3/DAPI) in M. planirostris showed that the nucleolus organizer regions (NORs) are weakly CMA3 positive and DAPI negative. In the three species, triple staining with CMA3/DA/DAPI revealed R-banding with CMA3 and uniform staining with DAPI. The ribosomal cistrons detected by FISH were present only in the pair 5 in both species of Molossus, and in two pairs of medium sized chromosomes (pairs 9 and 10) of Molossops planirostris. The results obtained by FISH, compared with those by AgNO3 staining, indicated that all NORs in these species are transcriptionally active.


Assuntos
Quirópteros/genética , Bandeamento Cromossômico , Cromossomos/química , Hibridização in Situ Fluorescente/métodos , Animais , Centrômero/química , Heterocromatina/genética , Cariotipagem/métodos , Região Organizadora do Nucléolo/genética , Sensibilidade e Especificidade , Coloração pela Prata
20.
Hereditas ; 136(2): 137-43, 2002.
Artigo em Inglês | MEDLINE | ID: mdl-12369099

RESUMO

We analyzed the nucleolus organizer regions (NORs) of thirteen bats from genera Phyllostomus, Phylloderma, Trachops, Tonatia, Sturnira, Platyrrhinus, Artibeus and Glossophaga. We used silver staining and FISH with rDNA probe. Nine species had only one Ag-NOR-bearing chromosome pair. Artibeus lituratus, A. jamaicensis and A. fimbriatus presented multiple Ag-NORs located in the short arms of pairs 5, 6 and 7, and an additional mark in the long arm of one chromosome 5 in A. fimbriatus. Artibeus cinereus showed Ag-NORs in the chromosome pairs 10 and 13. The chromosomal location of rRNA genes using FISH agreed with the number and position of NORs in all but one species. In A. cinereus the hybridization signals were seen in three chromosome pairs 9, 10 and 13. This suggests the occurrence of silent NORs in pair 9. Differences in the size and intensity of the hybridization signals were also observed in the pair 9 of A. cinereus.


Assuntos
Quirópteros/genética , Região Organizadora do Nucléolo , RNA Ribossômico/genética , Animais , Mapeamento Cromossômico , Cromossomos/ultraestrutura , Hibridização in Situ Fluorescente , Cariotipagem , Metáfase , Hibridização de Ácido Nucleico , Coloração pela Prata
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