RESUMO
Adaptation to different environments can promote population divergence via natural selection even in the presence of gene flow - a phenomenon that typically occurs during ecological speciation. To elucidate how natural selection promotes and maintains population divergence during speciation, we investigated the population genetic structure, degree of gene flow and heterogeneous genomic divergence in three closely related Japanese phytophagous ladybird beetles: Henosepilachna pustulosa, H. niponica and H. yasutomii. These species act as a generalist, a wild thistle (Cirsium spp.) specialist and a blue cohosh (Caulophyllum robustum) specialist, respectively, and their ranges differ accordingly. The two specialist species widely co-occur but are reproductively isolated solely due to their high specialization to a particular host plant. Genomewide amplified fragment-length polymorphism (AFLP) markers and mitochondrial cytochrome c oxidase subunit I (COI) gene sequences demonstrated obvious genomewide divergence associated with both geographic distance and ecological divergence. However, a hybridization assessment for both AFLP loci and the mitochondrial sequences revealed a certain degree of unidirectional gene flow between the two sympatric specialist species. Principal coordinates analysis (PCoA) based on all of the variable AFLP loci demonstrated that there are genetic similarities between populations from adjacent localities irrespective of the species (i.e. host range). However, a further comparative genome scan identified a few fractions of loci representing approximately 1% of all loci as different host-associated outliers. These results suggest that these three species had a complex origin, which could be obscured by current gene flow, and that ecological divergence can be maintained with only a small fraction of the genome is related to different host use even when there is a certain degree of gene flow between sympatric species pairs.
Assuntos
Besouros/genética , Fluxo Gênico , Deriva Genética , Análise do Polimorfismo de Comprimento de Fragmentos Amplificados , Animais , Especiação Genética , Seleção GenéticaRESUMO
Detecting the isolating barrier that arises earliest in speciation is critically important to understanding the mechanism of species formation. We tested isolating barriers between host races of a phytophagous ladybird beetle, Henosepilachna diekei (Coleoptera: Coccinellidae: Epilachnine), that occur sympatrically on distinct host plants. We conducted field surveys for the distribution of the beetles and host plants, rearing experiments to measure six potential isolating factors (adult host preference, adult and larval host performance, sexual isolation, egg hatchability, F(1) hybrid inviability, and sexual selection against F(1) hybrids), and molecular analyses of mitochondrial ND2 and the nuclear ITS2 sequences. We found significant genetic divergence between the host races, and extremely divergent host preference (i.e. habitat isolation) and host performance (i.e. immigrant inviability), but no other isolating barriers. The fidelity to particular host plants arises first and alone can prevent gene flow between differentiating populations of phytophagous specialists.
Assuntos
Besouros/fisiologia , Comportamento Alimentar/fisiologia , Animais , DNA Intergênico/genética , DNA Mitocondrial/genética , Demografia , Especiação Genética , Variação Genética , Indonésia , Espécies Introduzidas , Lamiaceae , Larva/fisiologia , Mikania , Especificidade da EspécieRESUMO
Synovial sarcoma of the mediastinum is a rare neoplasm that has overlapping histological and immunophenotypic features with other tumors in the differential diagnosis. We describe a case of this disease. The tumor was located at the right side of the pericardium, where an FDG-PET scan showed an uptake. It was resected, a resection which was complicated by the necessity of partially resecting the pericaridium and right middle lobe which were invaded by the tumor. The doubling time of the main tumor was 11.8 days. The margin of the resected specimen was tumor-free both macro- and microscopically. Reverse transcription-PCR confirmed the diagnosis of synovial sarcoma. The patient rejected chemotherapy or radiation therapy, and had recurrent tumors only one month after the operation. Finally, she opted to have only palliative care and died 79 days after the operation.
Assuntos
Neoplasias do Mediastino/patologia , Sarcoma Sinovial/patologia , Idoso , Evolução Fatal , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias do Mediastino/genética , Neoplasias do Mediastino/cirurgia , Invasividade Neoplásica , Recidiva Local de Neoplasia , Proteínas de Fusão Oncogênica/genética , Cuidados Paliativos , Tomografia por Emissão de Pósitrons , Sarcoma Sinovial/genética , Sarcoma Sinovial/cirurgia , Toracotomia , Tomografia Computadorizada por Raios X , Recusa do Paciente ao TratamentoRESUMO
Trade-offs in host-plant use are thought to promote the evolution of host specificity. However, usually either positive or no genetic correlations have been found. Whereas factors enhancing variation in overall viability have been claimed to mask negative genetic correlations, alternative hypotheses emphasize the sequential changes in genetic correlation in the course of host-range evolution. In this study, the genetic architectures of performances on different hosts were compared in two populations of the herbivorous ladybird beetle, Epilachna pustulosa, using three host plants, one being normal for both, one novel for only one population, and the other novel for both populations. The genetic correlations between larval periods on normal hosts were significantly positive whereas those between normal and novel hosts were not different from zero. There was no evidence for reduced genetic variation on the normal host-plants. These results suggest that the host-range is not restricted by the antagonistic genetic associations among exploitation abilities on different plant species, but rather that selection of different host-plants may improve the coordination between genes responsible for the use of different plants.
Assuntos
Evolução Biológica , Besouros/genética , Variação Genética , Plantas Comestíveis , Adaptação Fisiológica , Animais , Comportamento Alimentar , Feminino , Masculino , Dinâmica PopulacionalRESUMO
Local populations of herbivore species that display variation in host plant use are subject to natural selection for improved ability to use their own host species. Since natural selection changes the frequency of alleles that control host use, genetic variation in growth performance on host plants may change with each generation of selection. Therefore, within-population variations in the ability to use different hosts may reflect past selective forces. The present study reports the genetic variation in growth performance in a population of the herbivorous ladybird beetle, Epilachna vigintioctomaculata Motschulsky (Coccinellidae, Epilachninae) on both the normal host and a novel host. The present study found higher heritabilities for growth performance on the novel host than the normal host. The difference in heritabilities was caused by smaller among-family variance components on the normal host compared to those on the novel host. The results are compatible with the view that natural selection, which improved the ability of the population to use a particular host plant, has reduced genetic variation within that population in the ability to use that host plant. The pattern of reduced genetic variation in a population reared on the normal host observed in the present study is compared with that in another population, which showed local adaptation in the use of its own host plant. The effect of natural selection on differing host plant use on within-population genetic variation is discussed.
Assuntos
Besouros/genética , Besouros/fisiologia , Adaptação Fisiológica , Animais , Feminino , Variação Genética , Masculino , Plantas/parasitologia , Dinâmica Populacional , Seleção GenéticaRESUMO
To unearth glioma-specific genes in human glioblastoma, the serial analysis of gene expression technique was applied to a primary glioblastoma, using cultured human astrocytes as a normal control. Among the top 147 most-expressed tags in glioblastoma, we found a tag, TTTTGGGTAT, that originated from an unidentified gene and which was not detected in human astrocyte cultures. Real-time quantitative reverse transcription-PCR showed that MAGE-E1 expression was 2.6-15-fold enriched in glioblastoma relative to human astrocytes. Expressed sequence tags containing this tag were homologous to the melanoma-associated antigen gene (MAGE) family, and this new cDNA, named MAGE-E1, was cloned by the 5'-rapid amplification of cDNA ends technique. Three alternatively spliced variants (MAGE-E1a-c) were found, and deduced amino acid sequence showed that MAGE-E1a and -E1b shared the MAGE-conserved region, whereas -E1c did not. This suggests that although MAGE-E1c is expressed from one of the MAGE family, it has distinct functions from other members. Tissue distribution analysis showed that MAGE-E1 was distinct from other MAGEs. MAGE-E1 expression was detected only in brain and ovary among normal tissues. Interestingly, MAGE-E1a and/or -E1b were specifically expressed in glioma cells among cancer cells. These results indicate that MAGE-E1 is a novel and glioma-specific member of MAGE family.
Assuntos
Antígenos de Neoplasias/genética , Neoplasias Encefálicas/genética , Glioblastoma/genética , Antígenos de Neoplasias/biossíntese , Astrócitos/imunologia , Sequência de Bases , Neoplasias Encefálicas/imunologia , Clonagem Molecular , DNA Complementar/genética , Regulação Neoplásica da Expressão Gênica , Glioblastoma/imunologia , Humanos , Dados de Sequência Molecular , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Homologia de Sequência de Aminoácidos , Regulação para CimaRESUMO
Analyses of a part of mitochondrial cytochrome c oxidase I gene sequences (645 bp) for seventeen individuals of Epilachna vigintioctopunctata (Fabricius) from eight localities in east and southeast Asia revealed that the populations are divided into two genetically distinct groups (Chiba, Tokyo, Naha, Iriomote, Bangkok vs. Kuala Lumpur, Padang, Bogor). The number of nucleotide substitutions between sequences of different groups was 57-60, while that between sequences within each group was 1-8. Karyotypes of the two groups were also distinctly different. Crossing experiments showed that there exist strong postmating barriers between the two groups: eggs obtained from between-group crossings usually did not hatch, whereas more than 90% of eggs from within-group crossings hatched. It is concluded that E. vigintioctopunctata, a notorious pest of solanaceous crops in Asia and Australia, is composed of at least two reproductively isolated biological species that probably occupy different geographic ranges.
RESUMO
We encountered a case of pulmonary tumorlet with caseous granuloma associated with atypical mycobacterium. A 73-year-old woman was admitted to the hospital because a chest x-ray film showed enlargement of an abnormal shadow in the middle lobe of the right lung. Primary lung cancer was suspected and right middle lobectomy was performed. Acid-fast bacilli (Gaffky 1) were found in a caseous lesion and examination of intraoperatively obtained frozen specimens showed caseous granulomas. The bacilli were later identified as Mycobacterium avium complex. The permanent specimen showed a minute lesion consisting of small clusters of epithelial cells resembling carcinoid tumor in contact with granulomatous tissue. Histopathological examination revealed argyrophilia on Grimelius stain and immunoreactivity to chromogranin-A in the clusters of epithelial cells. Although these results are consistent with small cell carcinoma or peripheral carcinoid tumor, pulmonary tumorlet was diagnosed because of the lesion's small and minimal cytologic atypia, and because of chronic pulmonary damage around the lesion. Pulmonary tumorlets are minute, usually microscopic, tumor-like lesions mostly found in damaged lung tissue obtained at autopsy or during surgery. Morphological diagnosis is sometimes very difficult, but recently these lesions have been regarded as hyperplastic lesions arising in pulmonary neuroendocrine cells (Kultschitzky cells) and caused by chronic pulmonary damage, such as hypoxia and inflammation. Pulmonary tumorlets must be considered in the differential diagnosis of minute lesions suspected to be small cell carcinoma or peripheral carcinoid tumor.
Assuntos
Pulmão/inervação , Infecções por Mycobacterium não Tuberculosas/complicações , Sistemas Neurossecretores/patologia , Tuberculoma/complicações , Tuberculose Pulmonar/complicações , Idoso , Cromogranina A , Cromograninas/análise , Diagnóstico Diferencial , Feminino , Humanos , Hiperplasia/diagnóstico , Hiperplasia/etiologiaRESUMO
We determined the nucleotide sequences of a part of the mitochondrial cytochrome c oxidase I gene (1,000 bp) for twelve species of Asian phytophagous ladybird beetles belonging to the genus Epilachna, and constructed molecular phylogenetic trees for ten "Henosepilachna" species, using two "Epilachna" species as outgroups. Based on the suggested phylogenetic trees, we discussed taxonomic issues and the direction of host shift in these epilachnines.
Assuntos
Besouros/genética , Complexo IV da Cadeia de Transporte de Elétrons/genética , Mitocôndrias/enzimologia , Filogenia , Sequência de Aminoácidos , Animais , Dados de Sequência MolecularRESUMO
A 56-year-old woman was admitted to our hospital with the chief complaint of left back pain. We detected left pleural effusion on chest X-ray and performed chest drainage. No malignant cells were detected in the effusion. Chest CT demonstrated a tumor shadow over the left diaphragm and left pleural effusion 6 months later. She underwent en bloc resection of the tumor and left diaphragm. Histological evaluation revealed malignant fibrous histiocytoma (MFH). Recurrent tumors were found in the abdomen 8 months after the operation, and she underwent resection of the abdominal recurrent tumors. Histological evaluation of the recurrent tumors also showed MFH. The patient died 28 months after the first operation.
Assuntos
Diafragma , Histiocitoma Fibroso Benigno/cirurgia , Neoplasias Musculares/cirurgia , Diafragma/cirurgia , Feminino , Histiocitoma Fibroso Benigno/diagnóstico , Humanos , Pessoa de Meia-Idade , Neoplasias Musculares/diagnósticoRESUMO
Although lobectomy is standard therapy for Stage I non-small cell lung cancer, it often cannot be performed in poor-risk patients. In this report, we describe the results of a retrospective study to assess the usefulness of limited operation for stage I lung cancer. Over a 21-year period, 1,286 lung cancers were resected at our center. Among the 497 patients with stage I lung cancer, 36 sublobar resections were performed. There was only one surgery-related death, and the 5-year survival rate was 46% for all patients. At 5 years, survival was 69.2% for patients with squamous cell carcinoma and 33.7% for patients with adenocarcinoma. Survival rates were higher in patients who underwent mediastinoscopy than those who did not, and depended on histological findings and accurate pathological staging.
Assuntos
Neoplasias Pulmonares/cirurgia , Pneumonectomia/métodos , Adenocarcinoma/mortalidade , Adenocarcinoma/cirurgia , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Células Pequenas/mortalidade , Carcinoma de Células Pequenas/cirurgia , Carcinoma de Células Escamosas/mortalidade , Carcinoma de Células Escamosas/cirurgia , Feminino , Humanos , Neoplasias Pulmonares/mortalidade , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Taxa de SobrevidaRESUMO
A 68-year-old man presented to another hospital with progressive shortness of breath, dry cough, and systemic edema. A chest X-ray, echocardiogram, and chest CT showed a mediastinal mass and massive pericardial effusion. His symptoms improved after the treatment for heart failure. The pericardial effusion was bloody. In that, malignant cell wasn't proved. Thoracotomy was performed to diagnose the mediastinal tumor and to extirpate it. Pathological diagnosis after operation was thymoma with direct invasion to pericardium and tunica externa of aorta. Thymomas are routinely asymptomatic for prolonged periods of time. Symptomatic pericardial tamponade as initial manifestation due to a thymoma with a massive pericardial effusion is uncommon.
Assuntos
Tamponamento Cardíaco/etiologia , Timoma/complicações , Neoplasias do Timo/complicações , Idoso , Humanos , Masculino , Invasividade Neoplásica , Derrame Pericárdico/etiologia , Timoma/patologia , Neoplasias do Timo/patologiaRESUMO
A 64-year-old man who complained of the right chest pain was admitted in our hospital. A mass shadow which revealed the extrapleural sign was shown in the chest X-ray. This patient was performed thoracotomy and a tumor invading to the intercostal muscles was resected. Pathological diagnosis was benign fibrous mesothelioma. About 10 months after this operation, we suspected the local recurrence of the tumor on the chest X-ray. The re-operation was performed, and we resected the recurrent tumor and the 2nd and 3rd ribs. Pathologically the resected tumor was benign fibrous mesothelioma.
Assuntos
Mesotelioma/patologia , Recidiva Local de Neoplasia , Neoplasias Pleurais/patologia , Humanos , Masculino , Mesotelioma/cirurgia , Pessoa de Meia-Idade , Neoplasias Pleurais/cirurgia , ReoperaçãoRESUMO
A 60-year-old man with cough and fever was admitted to our hospital. Chest radiography revealed multiple bullae and fungus balls in both lungs. He was treated with MCZ and FCZ for about 2 months, but the chest radiograph shadows did not improve and the fever continued. A two-stage operation was performed. The bullae were incised and the fungus balls were removed, then a muscle flap plombage was made with a pectoralis major muscle, a latissimus dorsi muscle and an intercostal muscle. The postoperative course was uneventful and respiratory function was preserved.