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BACKGROUND AND PURPOSE: Spinal muscular atrophy (SMA) is the most important cause of motor neuron disease in childhood, and continues to represent the leading genetic cause of infant death. Adulthood-onset SMA (SMA type 4) is rare, with few isolated cases reported. The objective of the present study was to describe a cohort of patients with SMA type 4. METHODS: A cross-sectional study was conducted to characterize clinical, genetic, radiological and neurophysiological features of patients with adulthood-onset SMA. Correlation analysis of functional assessment with genetic, radiological and neurophysiological data was performed. RESULTS: Twenty patients with SMA type 4 were identified in a Brazilian cohort of 227 patients with SMA. The most common clinical symptom was limb-girdle muscle weakness, observed in 15 patients (75%). The most frequent neurological findings were absent tendon reflexes in 18 (90%) and fasciculations in nine patients (45%). Sixteen patients (80%) had the homozygous deletion of exon 7 in the SMN1 gene, with 12 patients (60%) showing four copies of the SMN2 gene. The functional scales Hammersmith Functional Motor Scale Expanded, Amyotrophic Lateral Sclerosis Functional Rating Scale Revised, Revised Upper Limb Module and Spinal Muscular Atrophy Functional Rating Scale, as well as the six-minute walk and the Time Up and Go tests showed a correlation with duration of disease. Motor Unit Number Index was correlated both with duration of disease and with performance in functional assessment. Radiological studies exhibited a typical pattern, with involvement of biceps femoris short head and gluteus minimus in all patients. CONCLUSION: This study represents the largest cohort of patients with SMA type 4 and provides functional, genetic, radiological and neurophysiological features that can be used as potential biomarkers for the new specific genetic therapies for SMA.
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Atrofia Muscular Espinal , Adulto , Estudios Transversales , Exones , Homocigoto , Humanos , Lactante , Atrofia Muscular Espinal/diagnóstico por imagen , Atrofia Muscular Espinal/genética , Eliminación de SecuenciaRESUMEN
Globally, community-based initiatives are effective in protecting ecosystems and the species within them. In this paper, we analyze the emergence and large-scale expansion of a community-based environmental protection system (the Voluntary Environmental Agents Program - VEA Program) in the Brazilian Amazon and identify factors that have determined its success since its inception, 25 years ago. Collective actions to protect the environment in the region have been undertaken by local people for at least 40 years, before their legal regulation in 2001 by the federal government of Brazil, and by the Amazonas state in 2007. The system is based on territorial surveillance and monitoring, and on guidelines for the better use of the territory and its natural resources. Between 1995 and 2020, the VEA Program expanded into the two protected areas where it was first implemented reaching approximately 9 thousand km2 of area protected by the system. The number of people participating also grew in this period by around 2050%, as did the participation of women, which grew by 5600%. The system was replicated in 37 protected areas in central Amazonia, and currently covers almost 200 thousand km2 of Amazon rainforest. From our analyses we unveil four main factors that may have allowed the VEA Program to expand and flourish: (a) the communities' previous demand for an effective control system, (b) its legal formalization and regulation, (c) the support from external institutions, and (d) the consolidation of community-based management programs to fund actions. These factors shall be further investigated as to confirm their critical role in the success of the VEA Program. We demonstrate that this community-based environmental protection system has established itself as a legitimate form of social control, and as a mechanism of socio-environmental governance in the areas in which it operates. By allowing more effective protection of territories, it generates consensus amongst users for the adequate management of natural resources, especially in contexts where government's actions are absent or inefficient. We claim that this system can be replicated in various parts of the world.
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Conservación de los Recursos Naturales , Ecosistema , Brasil , Política Ambiental , Femenino , HumanosRESUMEN
Workers in the waste sorting industry are exposed to diverse bioaerosols. Characterization of these bioaerosols is necessary to more accurately assess the health risks of exposure. The use of high-throughput DNA sequencing for improved analysis of microbial composition of bioaerosols, in combination with their in vitro study in relevant cell cultures, represents an important opportunity to find answers on the biological effects of bioaerosols. This study aimed to characterize by high-throughput sequencing the biodiversity present in complex aerosol mixtures retained in forklift air conditioning filters of a waste-sorting industry and its effects on cytotoxicity and secretion of proinflammatory cytokines in vitro using human macrophages derived from monocytic THP-1 cells. Seventeen filters from the filtration system from forklifts operating in one waste sorting facility and one control filter (similar filter without prior use) were analyzed using high-throughput sequencing and toxicological tests in vitro. A trend of positive correlation was seen between the number of bacterial and fungal OTUs (r = 0.47, p = 0.06). Seven filters (39%) exhibited low or moderate cytotoxicity (p < 0.05). The highest cytotoxic responses had a reduction in cell viability between 17 and 22%. Filter samples evoked proinflammatory responses, especially the production of TNFα. No significant correlation was found between fungal richness and inflammatory responses in vitro. The data obtained stress the need of thorough exposure assessment in waste-sorting industry and to take immunomodulatory properties into consideration for bioaerosols hazard characterization. The broad spectrum of microbial contamination detected in this study demonstrates that adequate monitoring of bioaerosol exposure is necessary to evaluate and minimize risks. The combined techniques can support the implementation of effective environmental monitoring programs of public and occupational health importance.
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Microbiota , Exposición Profesional , Aerosoles/análisis , Microbiología del Aire , Supervivencia Celular , Monitoreo del Ambiente , Hongos , Humanos , Exposición Profesional/análisis , Células THP-1RESUMEN
Maturity-Onset Diabetes of the Young (MODY) type 4 or PDX1 -MODY is a rare form of monogenic diabetes caused by heterozygous variants in PDX1 . Pancreatic developmental anomalies related to PDX1 are reported only in neonatal diabetes cases. Here, we describe dorsal pancreatic agenesis in 2 patients with PDX1 -MODY. The proband presented with diabetes since 14 years of age and maintained regular glycemic control with low doses of basal insulin and detectable C-peptide levels after 38 years with diabetes. A diagnosis of MODY was suspected. Targeted next-generation sequencing identified a heterozygous variant in PDX1 : c.188delC/p.Pro63Argfs*60. Computed tomography revealed caudal pancreatic agenesis. Low fecal elastase indicated exocrine insufficiency. His son had impaired glucose tolerance, presented similar pancreatic agenesis, and harbored the same allelic variant. The unusual presentation in this Brazilian family enabled expansion upon a rare disease phenotype, demonstrating the possibility of detecting pancreatic malformation even in cases of PDX1 -related diabetes diagnosed after the first year of life. This finding can improve the management of MODY4 patients, leading to precocious investigation of pancreatic dysgenesis and exocrine dysfunction.
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Anomalías Congénitas/genética , Diabetes Mellitus Tipo 2/genética , Proteínas de Homeodominio/genética , Páncreas/anomalías , Enfermedades Raras/genética , Transactivadores/genética , Brasil , Péptido C/genética , Preescolar , Anomalías Congénitas/diagnóstico , Anomalías Congénitas/fisiopatología , Diabetes Mellitus Tipo 2/diagnóstico , Diabetes Mellitus Tipo 2/fisiopatología , Intolerancia a la Glucosa/genética , Intolerancia a la Glucosa/fisiopatología , Heterocigoto , Humanos , Masculino , Persona de Mediana Edad , Mutación , Páncreas/fisiopatología , Elastasa Pancreática/genética , Fenotipo , Enfermedades Raras/diagnóstico , Enfermedades Raras/fisiopatologíaRESUMEN
Developmental risk factors, such as the exposure to stress or high levels of glucocorticoids (GCs), may contribute to the pathogenesis of anxiety disorders. The immunomodulatory role of GCs and the immunological fingerprint found in animals prenatally exposed to GCs point towards an interplay between the immune and the nervous systems in the etiology of these disorders. Microglia are immune cells of the brain, responsive to GCs and morphologically altered in stress-related disorders. These cells are regulated by adenosine A2A receptors, which are also involved in the pathophysiology of anxiety. We now compare animal behavior and microglia morphology in males and females prenatally exposed to the GC dexamethasone. We report that prenatal exposure to dexamethasone is associated with a gender-specific remodeling of microglial cell processes in the prefrontal cortex: males show a hyper-ramification and increased length whereas females exhibit a decrease in the number and in the length of microglia processes. Microglial cells re-organization responded in a gender-specific manner to the chronic treatment with a selective adenosine A2A receptor antagonist, which was able to ameliorate microglial processes alterations and anxiety behavior in males, but not in females.
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Ansiedad/metabolismo , Receptor de Adenosina A2A/fisiología , Animales , Trastornos de Ansiedad/patología , Células Cultivadas , Dexametasona/farmacología , Femenino , Glucocorticoides/metabolismo , Glucocorticoides/farmacología , Lipopolisacáridos/farmacología , Masculino , Microglía/efectos de los fármacos , Microglía/fisiología , Embarazo , Efectos Tardíos de la Exposición Prenatal , Ratas , Ratas Wistar , SexismoRESUMEN
Maturity-onset diabetes of the young (MODY) is a form of monogenic diabetes with autosomal dominant inheritance. GCK -MODY and HNF1A -MODY are the prevalent subtypes. Currently, there is growing concern regarding the correct interpretation of molecular genetic findings. The American College of Medical Genetics and Genomics (ACMG) updated guidelines to interpret and classify molecular variants. This study aimed to determine the prevalence of MODY ( GCK / HNF1A ) in a large cohort of Brazilian families, to report variants related to phenotype, and to classify them according to ACMG guidelines. One hundred and nine probands were investigated, 45% with clinical suspicion of GCK -MODY and 55% with suspicion of HNF1A -MODY. Twenty-five different variants were identified in GCK gene (30 probands-61% of positivity), and 7 variants in HNF1A (10 probands-17% of positivity). Fourteen of them were novel (12- GCK /2- HNF1A ). ACMG guidelines were able to classify a large portion of variants as pathogenic (36%- GCK /86%- HNF1A ) and likely pathogenic (44%- GCK /14%- HNF1A ), with 16% (5/32) as uncertain significance. This allows us to determine the pathogenicity classification more efficiently, and also reinforces the suspected associations with the phenotype among novel variants.
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Diabetes Mellitus Tipo 2/genética , Factor Nuclear 1-alfa del Hepatocito/genética , Proteínas Serina-Treonina Quinasas/genética , Adolescente , Adulto , Brasil/epidemiología , Niño , Preescolar , Estudios de Cohortes , Diabetes Mellitus Tipo 2/epidemiología , Diabetes Mellitus Tipo 2/patología , Femenino , Quinasas del Centro Germinal , Humanos , Masculino , Mutación , Fenotipo , Adulto JovenRESUMEN
Bryconamericus comprises 56 species distributed into three groups, on the basis of the position and shape of the maxillary teeth: B. exodon, B. microcephalus and B. iheringii groups. Few cytogenetic data are available for this genus, but the diploid number of 52 chromosomes is quite common, although the karyotypic variability is extensive. This study aimed to characterize a population of B. aff. iheringii and thus contribute more cytogenetic information and better understanding of the structure and karyotypic evolution of this genus. We found 6 cytotypes with different NOR patterns: cytotype I showed a karyotype formula of 12m+10sm+16st+14a (FN = 90) and single NORs; cytotype II with 18m+14sm+10st+10a (FN = 94) and cytotype III with 20m+18sm+4st+10a (FN = 94), showing both single and multiple NORs; cytotype IV with 20m+14sm+12st+6a (NF = 98), cytotype V with 22m+18sm+8st+4a (FN = 100) and cytotype VI with 18m+24sm+6st+4a (FN = 100), all with multiple NORs. Cytotype I is the most different in relation to FN and NOR pattern, and can be regarded as belonging to another species of the genus Bryconamericus, living in sympatry in Três Bocas Stream. The remaining cytotypes may have been generated by crosses between them and by pericentric inversions. Meiotic cells were also analyzed and showed that despite the high karyotypic variability, chromosome pairing occurred normally. The great variability found in B. aff. iheringii may be related to a high degree of polymorphism; nevertheless, the possibility of occurrence of more than one species in this location is not ruled out, demonstrating the need for conservation of the Três Bocas Stream.
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Characidae/genética , Variación Genética , Cariotipo , Animales , Brasil , Bandeo Cromosómico , Femenino , Genética de Población , Geografía , Hibridación Fluorescente in Situ , Masculino , MeiosisRESUMEN
The chicken (Gallus gallus) embryo has been used as a classic model system for developmental studies because of its easy accessibility for surgical manipulation during embryonic development. Sex determination in birds is chromosomally based (ZZ for males and ZW for females); however, the basic mechanism of sex determination is still unknown. Here, the dynamics of expression of candidate genes implicated in vertebrate sex determination and differentiation were studied during embryonic chicken gonadal development. Gene expression profiles were obtained before, during, and after gonadal sex differentiation in females and males for DMRT1, SOX3, SOX9, DAX1, SCII, HINTZ, HINTW, and the male hypermethylated (MHM) region. Transcripts for the HINTZ, DMRT1, DAX1, SCII, and SOX9 genes were observed in both sexes, but expression was higher in male gonads and may be correlated with testicular differentiation. The expression patterns of HINTW, SOX3, and MHM suggest that they may act in ovary development and may be involved in meiosis entry. MHM was upregulated and DMRT1 was downregulated in females at the same developmental stage. This may indicate a regulation of DMRT1 by MHM ncRNA. Similar dynamics were observed between HINTW and HINTZ. This study reports on the MHM expression profile during gonadal development and its correlation with the expression of genes involved in vertebrate sex determination.
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Gónadas/crecimiento & desarrollo , Procesos de Determinación del Sexo , Diferenciación Sexual/genética , Animales , Embrión de Pollo , Metilación de ADN/genética , Femenino , Regulación del Desarrollo de la Expresión Génica , Masculino , Cromosomas Sexuales/genética , Testículo/crecimiento & desarrollo , Testículo/metabolismoRESUMEN
Analyses conducted using repetitive DNAs have contributed to better understanding the chromosome structure and evolution of several species of insects. There are few data on the organization, localization, and evolutionary behavior of repetitive DNA in the family Lygaeidae, especially in Brazilian species. To elucidate the physical mapping and evolutionary events that involve these sequences, we cytogenetically analyzed three species of Lygaeidae and found 2n (â) = 18 (16 + XY) for Oncopeltus femoralis; 2n (â) = 14 (12 + XY) for Ochrimnus sagax; and 2n (â) = 12 (10 + XY) for Lygaeus peruvianus. Each species showed different quantities of heterochromatin, which also showed variation in their molecular composition by fluorochrome staining. Amplification of the 18S rDNA generated a fragment of approximately 787 bp. The alignment of the consensus sequence with sequences from other species of Heteroptera deposited in the GenBank revealed a similarity of 98% with small differences. Fluorescent in situ hybridization with the 18S rDNA fragment revealed that this ribosomal gene was located in 1 autosomal pair at different positions in the three species. No cytogenetic data are available for these Brazilian species. The basal number and the possible chromosomal changes that occurred among the different species, as well as the evolution of these DNA sequences, are discussed.
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Mapeo Cromosómico , Hemípteros/genética , Heterocromatina , ARN Ribosómico 18S/genética , Animales , Secuencia de Bases , Bandeo Cromosómico , Cromosomas de Insectos , Femenino , Hibridación Fluorescente in Situ , Masculino , Datos de Secuencia Molecular , Fenotipo , ARN Ribosómico 18S/química , Alineación de Secuencia , Homología de Secuencia de Ácido NucleicoRESUMEN
The treatment of bone infections still involves systemic or local antibiotic therapy in high doses for prolonged periods. Current research focuses on the application of different drug delivery systems to the bone, aiming at a targeted local administration that will decrease the number of drugs used and their toxicity, compared to the systemic route. The gold standard in clinical practice is currently poly(methyl methacrylate) (PMMA) cement. The main drawback of PMMA, however, is that it is non-biodegradable, requiring a second follow-up surgery to remove the implant. Biodegradable delivery systems, on the other hand, are easily resorbable within the organism, and less invasive alternative with better patient compliance. Among biodegradable materials, natural and synthetic polymers are being studied as local drug delivery systems due to their excellent biocompatibility, sustained effect, and antibiotic release with high penetrability to infected bone and soft tissue. In this review, we focus on biodegradable polymeric platforms, such as micro- and nanoparticles, scaffolds, and hydrogels, as well as multi-delivery systems for targeting antibiotics to the bone. Additionally, we discuss the reported drug release profiles that provide important information about the systems' functionality.
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Antibacterianos , Osteomielitis , Humanos , Polimetil Metacrilato , Sistemas de Liberación de Medicamentos , Polímeros/uso terapéutico , Osteomielitis/tratamiento farmacológicoRESUMEN
Belostoma, a genus of the family Belostomatidae, includes species of great ecological importance as biocontrol agents. Few species of these species have been the subject of cytogenetic analyses. Karyotypic evolution in this genus involves agmatoploidy and simploidy; there are also different sex chromosome systems. We examined two Belostoma species (B. dilatatum and B. candidulum) collected from the Paranapanema River Basin (Brazil). Mitotic and meiotic analysis revealed 2n(â) = 26 + X1X2X3Y for B. dilatatum and 2n(â) = 14 + XY for B. candidulum; both karyotypes have holokinetic chromosomes. Differences in heterochromatin distribution were also observed between the species, besides variation in the localization of CMA3âº/DAPIâ» blocks. The existence of different types of sex chromosome systems in these species was confirmed based on arrangements of the chromosomes in different meiotic stages. We identified a new sex system in B. dilatatum, and make the first cytogenetic report on B. candidulum.
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Heterópteros/genética , Cromosomas Sexuales/genética , Animales , Evolución Molecular , Femenino , Colorantes Fluorescentes/metabolismo , Cariotipificación , Masculino , Meiosis/genética , Coloración y EtiquetadoRESUMEN
Loricariidae (Siluriformes, Hypostominae) is one of the most diverse catfish families. In spite of the wide distribution of loricariids in South America, cytogenetic reports are available for only a few species, mostly from southern and southeastern Brazil. We made the first chromosomal analysis of Hypostomus aff. unae from the Contas River basin in northeastern Brazil. Four populations isolated by short distances but from distinct landscapes were studied based on conventional staining, C-banding, argyrophilic nucleolar organizer regions (Ag-NOR), CMA(3)/DAPI fluorochrome staining, and fluorescent in situ hybridization with 18S rDNA probes. Although sharing the same diploid number (2n = 76) and NOR locations, each population presented exclusive karyotype formulae and specific patterns of heterochromatic and AT-rich regions. The derived karyotypes of H. aff. unae (2n >54; high number of acrocentrics bearing AT-rich interstitial heterochromatin) indicated a divergent karyoevolution, mostly driven by centric fissions, pericentric inversions and particular heterochromatin dispersion models. This finding of distinct evolutionary units in H. aff. unae will be useful for understanding the natural history of loricariids from relatively unexplored coastal basins in South America.
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Evolución Molecular , Peces/genética , Variación Genética , Cariotipificación , Animales , Secuencia de Bases , Cartilla de ADNRESUMEN
New strategies for the treatment of polymicrobial bone infections are required. In this study, the co-delivery of two antimicrobials by poly(D,L-lactic acid) (PDLLA) scaffolds was investigated in a polymicrobial biofilm model. PDLLA scaffolds were prepared by solvent casting/particulate leaching methodology, incorporating minocycline and voriconazole as clinically relevant antimicrobial agents. The scaffolds presented a sponge-like appearance, suitable to support cell proliferation and drug release. Single- and dual-species biofilm models of Staphylococcus aureus and Candida albicans were developed and characterized. S. aureus presented a higher ability to form single-species biofilms, compared to C. albicans. Minocycline and voriconazole-loaded PDLLA scaffolds showed activity against S. aureus and C. albicans single- and dual-biofilms. Ultimately, the cytocompatibility/functional activity of PDLLA scaffolds observed in human MG-63 osteosarcoma cells unveil their potential as a next-generation co-delivery system for antimicrobial therapy in bone infections.
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Antiinfecciosos , Staphylococcus aureus Resistente a Meticilina , Antibacterianos/farmacología , Antiinfecciosos/farmacología , Biopelículas , Candida albicans , Humanos , Ácido Láctico , Pruebas de Sensibilidad Microbiana , Minociclina , Staphylococcus aureus , VoriconazolRESUMEN
A large number of genera in the tropical fish family Characidae are incertae sedis. Cytogenetic analysis was made of four of these species: Astyanax eigenmanniorum, Deuterodon stigmaturus, Hyphessobrycon luetkenii, and H. anisitsi, collected from various hydrographic basins: hydrographic system from Laguna dos Patos/RS, Tramandaí basin/RS and Tibagi River basin/PR. The first two species were collected in their type locality in the State of Rio Grande do Sul. The 2n = 48 karyotype was observed only in A. eigenmanniorum, while the other species had 2n = 50 chromosomes, with different karyotypic formulas. There was weak heterochromatin staining in the pericentromeric region of A. eigenmanniorum, D. stigmaturus and H. luetkenni chromosomes. In H. anisitsi, heterochromatin appeared to be more abundant and distributed in the pericentromeric and terminal regions of the chromosomes; three pairs showed more evident heterochromatic blocks. There were multiple Ag-NORs in all populations, visualized by FISH with an 18S rDNA probe. While D. stigmaturus and H. luetkenii had conserved AgNOR, CMA3 and 18S rDNA sites, the other two species showed intra- and interindividual variation at these sites. The karyotype variability was high, as is common in this group of fish. Different species arising from isolated hydrographic basins maintain an elevated level of karyotype differentiation, mainly with respect to chromosome structure, heterochromatin distribution and rDNA localization. This is the first report with cytogenetic data for D. stigmaturus and H. luetkenii.
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Antígenos Nucleares/genética , Characidae/clasificación , Characidae/genética , Cromomicina A3/metabolismo , ADN Ribosómico/genética , Variación Genética , Cariotipificación , Animales , Brasil , Bandeo Cromosómico , Cromosomas/genética , Femenino , Geografía , Hibridación Fluorescente in Situ , Indoles/metabolismo , Masculino , Metafase/genética , Ríos , Especificidad de la EspecieRESUMEN
BACKGROUND: It is noteworthy that there is a clear clinical, epidemiological and pathophysiological association between upper and lower airway inflammation in rhinitis and asthma. OBJECTIVE: The aim of this study was to compare the eosinophil counts in induced sputum and nasal lavage fluids in asthma, checking their association and the accuracy of nasal eosinophilia as a predictor of sputum eosinophilia by a cross-sectional study. METHODS: The clinical evaluation, asthma control questionnaire (ACQ), pre- and post-bronchodilator spirometry, nasal and sputum sample was performed. The nasal eosinophilia was analysed by a receiver operating curve and logistic regression model. RESULTS: In 140 adults, the post-bronchodilator forced expiratory volume in 1 s (FEV(1)) did not differ between patients with or without sputum eosinophilia (0.18). After adjusted for upper airway symptoms, age, ACQ score and post-bronchodilator FEV(1), sputum eosinophilia was associated with 52 times increase in odds of nasal eosinophilia, whereas each 1% increase in bronchodilator response was associated with 7% increase in odds of nasal eosinophilia. CONCLUSION: This study brings further evidence that upper airway diseases are an important component of the asthma syndrome. Furthermore, monitoring of nasal eosinophilia by quantitative cytology may be useful as a surrogate of sputum cytology in as a component of composite measurement for determining airway inflammation.
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Asma , Eosinofilia/diagnóstico , Inflamación , Nariz/inmunología , Administración Intranasal , Adulto , Asma/diagnóstico , Asma/inmunología , Asma/fisiopatología , Estudios Transversales , Eosinofilia/inmunología , Eosinófilos/citología , Eosinófilos/inmunología , Femenino , Humanos , Inflamación/inmunología , Inflamación/fisiopatología , Recuento de Leucocitos , Masculino , Persona de Mediana Edad , Líquido del Lavado Nasal , Esputo/inmunologíaAsunto(s)
Eosinófilos , Recuento de Leucocitos , Lavado Nasal (Proceso) , Esputo/citología , Asma/diagnóstico , Humanos , Curva ROCAsunto(s)
Queilitis/patología , Pénfigo/patología , Femenino , Humanos , Persona de Mediana Edad , Mucosa Bucal/patologíaRESUMEN
Five specimens of Rhamdia quelen collected from the Lindóia Stream, PR, Brazil, were cytogenetically analyzed. The diploid chromosome number found was 58, including 30 metacentric, 16 submetacentric, 10 subtelocentric, and 2 acrocentric chromosomes. Supernumerary or B chromosomes, frequently observed in this fish group, were not detected. One of the individuals was triploid, with 3n = 87. A silver-stained nucleolar organizer region was found on a pair of submetacentric chromosomes of the diploid specimens, and on three chromosomes of the triploid individual, confirming triploidy. Treatment with fluorochrome chromomycin A(3) revealed fluorescent bands coincident with those of the silver-stained nucleolar organizer region, in both diploid and triploid individuals, showing that this is a GC-rich region. Heterochromatin distribution was visualized by the C-banding technique, mainly in the terminal chromosome regions of the individuals and was also observed in the pericentromeric regions of some chromosomes and at both telomeres.
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Bagres/genética , Poliploidía , Animales , Brasil , Citogenética/métodosRESUMEN
Six populations of Hoplias malabaricus from the Lower Paranapanema River were studied and showed 2n = 40 with metacentric/submetacentric chromosomes for females and 2n = 39 with m/sm chromosomes for males, thereby revealing a multiple sex chromosome system of the X(1)X(1)X(2)X(2)/X(1)X(2)Y type. The Y chromosome was the largest metacentric chromosome in all karyotypes. The heterochromatic blocks were located in a pericentromeric region of all pairs and in telomeric regions in some other pairs. A conspicuous pericentromeric C-band was detected in a single pair, equivalent to the X(1) chromosome. No markers on X(2) chromosomes were detected, but they could be identified by their size. The females displayed the same distribution of C and chromomycin A(3) bands and 18S rDNA sites among the populations. However, the males exhibited differences in both number and position of Giemsa C-bands on the Y chromosome, which were also evident after Chromomycin A(3) banding and FISH with the 18S rDNA probe. These cytogenetic tools allowed for the identification of possible mechanisms involved in the differentiation and evolution of the Y chromosome.
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Peces/genética , Cromosoma X , Cromosoma Y , Animales , Brasil , Bandeo Cromosómico , Femenino , Hibridación Fluorescente in Situ , Cariotipificación , MasculinoRESUMEN
Cytogenetic and morphometric analyses were carried out in Hoplias aff. malabaricus specimens from six distinct populations from the lower Paranapanema River basin, located between the states of Paraná and São Paulo, Brazil. Measurements were also taken from a specimen collected in Surinam. In a population from a fish farm station at Universidade do Norte do Parana (EPUNOPAR), two sympatric cytotypes (2n = 40 and 2n = 42 chromosomes) are found. A population from a fish farm station at Universidade Estadual de Londrina (EPUEL) shows 2n = 42 meta-submetacentric chromosomes for males and females with a simple sex chromosome system of XX/XY type. Populations from the Vermelho and Rancho Alegre Rivers, Três Bocas Stream and Paranapanema River have 2n = 39 chromosomes in males and 2n = 40 chromosomes in females, showing a multiple sex chromosome system of X(1)X(1)X(2)X(2)/X(1)X(2)Y type. Twenty morphological variables were studied. These measurements were used for an analysis of the canonical variables and standard analysis of proportional measurements. The most variable measurements among the specimens are the maxilla length (MXL) and the pre-dorsal distance (PDD). Analysis of canonical variables indicates three distinct groups in the first canonical axis formed by: (1) Três Bocas Stream, (2) Rancho Alegre + Vermelho River + EPUNOPAR and (3) EPUEL + Paranapanema River. This axis retained 79.4% of information from the original matrix. Analysis of morphometrics reveals differences among populations from the Paranapanema River basin and between these and the specimen from Surinam. The morphometric and cytogenetic differences among the studied populations suggest a species complex.