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1.
Eur J Neurol ; 25(1): 142-147, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28921817

RESUMO

BACKGROUND AND PURPOSE: To establish and validate diagnostic criteria for adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) due to colony-stimulating factor 1 receptor (CSF1R) mutation. METHODS: We developed diagnostic criteria for ALSP based on a recent analysis of the clinical characteristics of ALSP. These criteria provide 'probable' and 'possible' designations for patients who do not have a genetic diagnosis. To verify its sensitivity and specificity, we retrospectively applied our criteria to 83 ALSP cases who had CSF1R mutations (24 of these were analyzed at our institutions and the others were identified from the literature), 53 cases who had CSF1R mutation-negative leukoencephalopathies and 32 cases who had cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) with NOTCH3 mutations. RESULTS: Among the CSF1R mutation-positive cases, 50 cases (60%) were diagnosed as 'probable' and 32 (39%) were diagnosed as 'possible,' leading to a sensitivity of 99% if calculated as a ratio of the combined number of cases who fulfilled 'probable' or 'possible' to the total number of cases. With regard to specificity, 22 cases (42%) with mutation-negative leukoencephalopathies and 28 (88%) with CADASIL were correctly excluded using these criteria. CONCLUSIONS: These diagnostic criteria are very sensitive for diagnosing ALSP with sufficient specificity for differentiation from CADASIL and moderate specificity for other leukoencephalopathies. Our results suggest that these criteria are useful for the clinical diagnosis of ALSP.


Assuntos
Axônios/patologia , Leucoencefalopatias/diagnóstico , Leucoencefalopatias/genética , Neuroglia/patologia , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos/genética , Esferoides Celulares/patologia , Adolescente , Adulto , Idoso , CADASIL/diagnóstico , CADASIL/genética , CADASIL/patologia , Transtornos Cognitivos/etiologia , Diagnóstico Diferencial , Feminino , Humanos , Leucoencefalopatias/patologia , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Receptor Notch3/genética , Reprodutibilidade dos Testes , Tomografia Computadorizada por Raios X , Adulto Jovem
2.
J Evol Biol ; 30(6): 1205-1218, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28425150

RESUMO

Somatic cellular differentiation plays a critical role in the transition from unicellular to multicellular life, but the evolution of its genetic basis remains poorly understood. By definition, somatic cells do not reproduce to pass on genes and so constitute an extreme form of altruistic behaviour. The volvocine green algae provide an excellent model system to study the evolution of multicellularity and somatic differentiation. In Volvox carteri, somatic cell differentiation is controlled by the regA gene, which is part of a tandem duplication of genes known as the reg cluster. Although previous work found the reg cluster in divergent Volvox species, its origin and distribution in the broader group of volvocine algae has not been known. Here, we show that the reg cluster is present in many species without somatic cells and determine that the genetic basis for soma arose before the phenotype at the origin of the family Volvocaceae approximately 200 million years ago. We hypothesize that the ancestral function was involved in regulating reproduction in response to stress and that this function was later co-opted to produce soma. Determining that the reg cluster was co-opted to control somatic cell development provides insight into how cellular differentiation, and with it greater levels of complexity and individuality, evolves.


Assuntos
Evolução Biológica , Filogenia , Volvox , Adaptação Fisiológica , Clorófitas , Estresse Fisiológico
3.
AJNR Am J Neuroradiol ; 38(1): 77-83, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27633805

RESUMO

Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia is a rare neurodegenerative disease resulting from mutations in the colony stimulating factor 1 receptor gene. Accurate diagnosis can be difficult because the associated clinical and MR imaging findings are nonspecific. We present 9 cases with intracranial calcifications distributed in 2 brain regions: the frontal white matter adjacent to the anterior horns of the lateral ventricles and the parietal subcortical white matter. Thin-section (1-mm) CT scans are particularly helpful in detection due to the small size of the calcifications. These calcifications had a symmetric "stepping stone appearance" in the frontal pericallosal regions, which was clearly visible on reconstructed sagittal CT images. Intrafamilial variability was seen in 2 of the families, and calcifications were seen at birth in a single individual. These characteristic calcification patterns may assist in making a correct diagnosis and may contribute to understanding of the pathogenesis of leukoencephalopathy.


Assuntos
Calcinose/diagnóstico por imagem , Leucoencefalopatias/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Adulto , Axônios , Calcinose/patologia , Feminino , Humanos , Leucoencefalopatias/patologia , Masculino , Neuroglia
4.
Eur J Neurol ; 24(1): 37-45, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27680516

RESUMO

BACKGROUND AND PURPOSE: The clinical characteristics of colony stimulating factor 1 receptor (CSF1R) related adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) have been only partially elucidated. METHODS: Clinical data from CSF1R mutation carriers who had been seen at our institutions or reported elsewhere were collected and analysed using a specific investigation sheet to standardize the data. RESULTS: In all, 122 cases from 90 families with CSF1R mutations were identified. The mean age of onset was 43 years (range 18-78 years), the mean age at death was 53 years (range 23-84 years) and the mean disease duration was 6.8 years (range 1-29 years). Women had a significantly younger age of onset than men (40 vs. 47 years, P = 0.0006, 95% confidence interval 3.158-11.177). There was an age-dependent penetrance that was significantly different between the sexes (P = 0.0013). Motor dysfunctions were the most frequent initial symptom in women whose diseases began in their 20s. Thinning of the corpus callosum, abnormal signalling in pyramidal tracts, diffusion-restricted lesions and calcifications in the white matter were characteristic imaging findings of ALSP. The calcifications were more frequently reported in our case series than in the literature (54% vs. 3%). Seventy-nine per cent of the mutations were located in the distal part of the tyrosine kinase domain of CSF1R (102 cases). There were no apparent phenotype-genotype correlations. CONCLUSIONS: The characteristics of ALSP were clarified. The phenotype of ALSP caused by CSF1R mutations is affected by sex.


Assuntos
Leucoencefalopatias/genética , Leucoencefalopatias/patologia , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos/genética , Adolescente , Adulto , Idade de Início , Idoso , Idoso de 80 Anos ou mais , Axônios/patologia , Corpo Caloso/diagnóstico por imagem , Corpo Caloso/patologia , Feminino , Heterozigoto , Humanos , Leucoencefalopatias/diagnóstico por imagem , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Transtornos dos Movimentos/etiologia , Transtornos dos Movimentos/fisiopatologia , Mutação/genética , Neuroglia/patologia , Penetrância , Tratos Piramidais/diagnóstico por imagem , Tratos Piramidais/patologia , Caracteres Sexuais , Substância Branca/diagnóstico por imagem , Substância Branca/patologia , Adulto Jovem
6.
Neurology ; 71(8): 547-51, 2008 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-18579805

RESUMO

BACKGROUND: Spinocerebellar ataxia type 15 (SCA15) is a progressive neurodegenerative disorder characterized by pure cerebellar ataxia, very slow progression, and distinct cerebellar atrophy. The locus for SCA15 was first mapped to 3p24.2-3pter in an Australian family. We have subsequently mapped two Japanese families presenting with ataxia and postural tremor of the head, arm, or trunk to the SCA15 locus. Recently, partial deletions involving both the type 1 inositol 1,4,5-triphosphate receptor (ITPR1) and sulfatase modifying factor 1 (SUMF1) genes have been identified in Australian and British families with SCA15. METHODS: We conducted fine haplotype analysis on the region including ITPR1. To identify the deletion, we conducted gene dosage analysis and array-based comparative genomic hybridization (aCGH) analysis. Gene expression analysis was performed using quantitative real-time reverse transcription PCR. Mutational analyses of ITPR1 and SUMF1 were also performed. RESULTS: We have identified a 414-kb deletion including the entire ITPR1 and exon 1 of SUMF1 in patients in family A. The expression levels of ITPR1 and SUMF1 mRNAs of the patient were half those of the normal control. Furthermore, in family B, we have identified a C-to-T substitution at position 8581 of ITPR1, resulting in the amino acid substitution of leucine for proline at codon 1059, which is highly conserved among species. CONCLUSIONS: Our results strongly confirm that ITPR1 is the causative gene for SCA15 and suggest that we need to investigate the point mutation in ITPR1 in the patients with autosomal dominant cerebellar ataxia and tremor.


Assuntos
Deleção de Genes , Receptores de Inositol 1,4,5-Trifosfato/genética , Mutação de Sentido Incorreto , Deleção de Sequência/genética , Ataxias Espinocerebelares/genética , Sulfatases/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Substituição de Aminoácidos/genética , Austrália , Análise Mutacional de DNA , Progressão da Doença , Feminino , Genes Dominantes , Haplótipos , Heterozigoto , Humanos , Japão , Masculino , Pessoa de Meia-Idade , Oxirredutases atuantes sobre Doadores de Grupo Enxofre , Linhagem , Mutação Puntual , Tremor/genética
7.
Phys Rev Lett ; 99(8): 087601, 2007 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-17930981

RESUMO

The magnetism of LixCoO2 (LCO), which has a similar structure to NaxCoO2 (NCO), has been investigated by muon-spin spectroscopy and susceptibility measurements using samples with x=0.1-1 prepared by an electrochemical reaction. In the x range below 0.75, LCO was found to be Pauli paramagnetic down to 1.8 K, suggesting an intermediate- or weak-coupling regime, although disordered local moments, with volume fractions below approximately 20%, appear at low T for LCO with x > or = 0.5. The phase diagram and interactions of LCO are thus strikingly different from NCO, while the differences cannot be explained simply by structural differences between the two systems.


Assuntos
Cobalto , Magnetismo , Cobalto/química
8.
Phys Rev Lett ; 96(19): 197206, 2006 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-16803139

RESUMO

The quasi-one-dimensional (Q1D) cobalt oxides A(N + 2)Co(n + 1)O(3n + 3) (A = Ca, Sr, and Ba, n = 1 - infinity) were investigated by muon-spin spectroscopy under applied pressures of up to 1.1 GPa. The relationship between the onset Néel temperature T(on)(N) and the interchain distance (d(ic)), which increases monotonically with n, is well fitted by the formula T(N)/T(N,0) = (1 - d(ic)/d(ic,o)(beta), here for T(on)(N) approximately 100 K for Ca(3)Co(2)O(6) (n = 1) and approximately 15 for BaCoCoO(3) (n = infinity at ambient P. The T(on)(N) - d(ic) curve also predicts a large dependence of Y(N) for the compounds with n > or = 5, i.e., in the vicinity of , while the compounds show only a very small effect. Indeed, our high-pressure mu(+) results show that of BaCoO(3) is enhanced by with a slope of 2.2 K(Gpa), whereas no detectable changes by P for both Ca(3)Co(2)O(6) and Sr(4)Co(3)O(9) (n = 2). This clearly confirms the role of the 2D-antiferromagnetic interaction on T(on)(N) in the Q1D cobalt oxides.

9.
Phys Rev Lett ; 96(3): 037206, 2006 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-16486764

RESUMO

By means of muon-spin spectroscopy, we have found that K0.49CoO2 crystals undergo successive magnetic transitions from a high-T paramagnetic state to a magnetic ordered state below 60 K and then to a second ordered state below 16 K, even though K0.49CoO2 is metallic at least down to 4 K. An isotropic magnetic behavior and wide internal-field distributions suggest the formation of a commensurate helical spin density wave (SDW) state below 16 K, while a linear SDW state is likely to exist above 16 K. It was also found that exhibits a further transition at 150 K presumably due to a change in the spin state of the Co ions. Since the dependence of the internal-field below 60 K was similar to that for Na0.5CoO2, this suggests that magnetic order is more strongly affected by the Co valence than by the interlayer distance or interaction and/or the charge ordering.

10.
Clin Exp Immunol ; 143(3): 427-34, 2006 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-16487241

RESUMO

To serologically determine the association of microbial superantigens and the pathogenesis of Kawasaki disease (KD), we conducted a case-control study. Serum IgG and IgM antibodies against staphylococcal enterotoxin A (SEA), SEB, SEC, toxic shock syndrome toxin-1 (TSST-1), and streptococcal pyrogenic exotoxin A (SPEA) were measured by an enzyme-linked immunosorbent assay in 293 serum samples from 65 KD patients on clinical days 1-28 and 120 control samples. The administration of immunoglobulin products, which contain high concentrations of IgG antibodies against all the superantigens, directly elevated antitoxin IgG antibodies in KD patients. In contrast, antitoxin IgM antibodies were not detected in immunoglobulin products. Actually, we found a significant elevation of IgM antibodies against SEA in KD patients in the first (median titre: 0.020, P < 0.01 versus control), second (0.024, P < 0.001), third (0.030, P < 0.001) and fourth (0.038, P < 0.001) weeks, compared to the controls (0.015). Significant differences of IgM antibodies were also true for SEB, TSST-1, and SPEA throughout the first to fourth weeks, and for SEC throughout the second to fourth weeks. The prevalence of KD patients having high IgM titres (> mean + 2SD of control values) to the 5 superantigens was increased with the clinical weeks, and reached 29-43% of KD subjects at the fourth week. This is the first study that describes kinetics of IgM antibodies against superantigens and clarifies the serological significance throughout the clinical course of KD. Our results suggest that multiple superantigens involve in the pathogenesis of KD.


Assuntos
Imunoglobulina M/sangue , Síndrome de Linfonodos Mucocutâneos/imunologia , Staphylococcus aureus/imunologia , Streptococcus pyogenes/imunologia , Superantígenos/imunologia , Anticorpos Antibacterianos/sangue , Proteínas de Bactérias/imunologia , Toxinas Bacterianas/imunologia , Estudos de Casos e Controles , Criança , Pré-Escolar , Enterotoxinas/imunologia , Exotoxinas/imunologia , Feminino , Humanos , Imunoglobulina G/sangue , Imunoglobulinas Intravenosas/uso terapêutico , Lactente , Masculino , Proteínas de Membrana/imunologia , Síndrome de Linfonodos Mucocutâneos/terapia
11.
J Comp Pathol ; 128(2-3): 192-4, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12634098

RESUMO

Large intracytoplasmic inclusions were observed in hepatocytes of a 7-year-old African elephant (Loxodonta africana). The inclusions were oval to polyhedral with either a homogeneous glassy or a granular appearance. They were positive for the periodic acid-Schiff (PAS) reaction. Electron microscopical examination revealed that the inclusions consisted of granular material with moderate electron-density and were membrane-bounded. The findings suggested that the inclusions were derived from endoplasmic reticulum. The light and electron microscopical features were similar to those of endoplasmic reticulum storage disease of the liver in man. Such inclusions have not previously been reported in animals.


Assuntos
Citoplasma/patologia , Elefantes , Hepatócitos/ultraestrutura , Corpos de Inclusão/ultraestrutura , Hepatopatias/veterinária , Animais , Citoplasma/metabolismo , Retículo Endoplasmático/metabolismo , Retículo Endoplasmático/ultraestrutura , Evolução Fatal , Técnicas Imunoenzimáticas/veterinária , Corpos de Inclusão/metabolismo , Hepatopatias/patologia , Microscopia Eletrônica/veterinária , Reação do Ácido Periódico de Schiff/veterinária
12.
J Antibiot (Tokyo) ; 54(7): 573-81, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11560376

RESUMO

Bio-probes that inhibit the action of auxin are useful tools for the study of auxin signaling. To screen for specific inhibitors of auxin signaling, we used an Arabidopsis transgenic line harboring the auxin-inducible promoter derived from PS-IAA4/5 and the reporter gene, GUS (beta-glucuronidase). In this transgenic plant, the exogenous auxin specifically enhanced the expression of the GUS reporter gene. A novel 22-membered spiroketal-macrolide, yokonolide A (1), and related previously known compound, A82548A (2), were isolated from Streptomyces diastatochromogenes B59 as inhibitors of auxin inducible gene expression. The absolute structure of I was determined by detailed spectral analyses and chemical derivatization. 1 and 2 completely inhibited the auxin-induced transcription of the reporter gene at 5 and 1 microm, respectively. In contrast, 1 and 2 did not affect the translation of GUS reporter transcripts. In addition, 1 and 2 did not inhibit the gibberellin-induced alpha-amylase expression at 100 microM in barley aleurone cells. These results suggest that 1 and 2 specifically inhibit auxin signaling leading to auxin-mediated gene expression.


Assuntos
Antibacterianos/farmacologia , Antimetabólitos/farmacologia , Ácidos Indolacéticos/antagonistas & inibidores , Macrolídeos , Transdução de Sinais/efeitos dos fármacos , Streptomyces/química , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antimetabólitos/química , Antimetabólitos/isolamento & purificação , Arabidopsis/efeitos dos fármacos , Arabidopsis/fisiologia , Fermentação , Espectroscopia de Ressonância Magnética , Conformação Molecular , Raízes de Plantas/efeitos dos fármacos , Streptomyces/classificação , Streptomyces/metabolismo
13.
J Neurosurg ; 95(3): 495-9, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11565873

RESUMO

OBJECT: Neurosurgically induced temporary occlusion of intracranial arteries carries the risk of cerebral ischemic damage. Because negative shifts in the cortical direct-current (DC) potential indicate tissue depolarization and, thus, critical ischemic stress, the authors hypothesized that recordings of these potentials could help to determine the optimal duration and frequency of induced intermittent focal ischemia to prevent brain injury. The investigators related the results of DC recordings both to simultaneously recorded decreases in extracellular Ca++ concentration ([Ca++]o), which reflect Ca++ entry into cells, and to histological outcome. METHODS: In cats anesthetized with halothane the effects of intermittent brief (10 minutes long, six times [6 x 10-min group]) and prolonged (20 minutes long, three times [3 x 20-min group]) episodes of middle cerebral artery occlusions were compared with those of a single continuous episode (1 x 60-min group). Laser Doppler flow probes and ion-selective microelectrodes were used to measure cerebral blood flow, DC potentials, and [Ca++]o in cortical tissues of ectosylvian gyri. Negative shifts in DC potential were evaluated in the three groups during the entire 60-minute-long period of ischemia and were smallest in the 6 x 10-min group, larger in the 3 x 20-min group, and largest in the 1 x 60-min group. Accordingly, infarct volumes were smallest in the 6 x 10-min group, intermediate in the 3 x 20-min group, and largest in the 1 x 60-min group. Decreases in ischemic [Ca++]o were significantly greater in the 1 x 60-min group than in the two groups in which there were repetitive occlusions, and recovery of [Ca++]o after reperfusion normalized only in the 1 x 60-min group. CONCLUSIONS: The DC potential may provide a reliable measure to optimize intermittent ischemia and to achieve minimal ischemic brain injury during temporary neurosurgical occlusion of cerebral arteries.


Assuntos
Isquemia Encefálica/fisiopatologia , Córtex Cerebral/irrigação sanguínea , Complicações Intraoperatórias/fisiopatologia , Monitorização Intraoperatória/instrumentação , Processamento de Sinais Assistido por Computador/instrumentação , Transmissão Sináptica/fisiologia , Animais , Isquemia Encefálica/patologia , Cálcio/metabolismo , Gatos , Córtex Cerebral/patologia , Córtex Cerebral/fisiopatologia , Eletroencefalografia/instrumentação , Feminino , Complicações Intraoperatórias/patologia , Masculino , Microeletrodos , Artéria Cerebral Média/patologia , Artéria Cerebral Média/cirurgia , Fluxo Sanguíneo Regional/fisiologia , Traumatismo por Reperfusão/patologia , Traumatismo por Reperfusão/fisiopatologia
14.
J Synchrotron Radiat ; 8(Pt 2): 455-6, 2001 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-11512812

RESUMO

We have measured magnetic circular dichroism (MCD) spectra at the transition-metal L2,3 edges in D03-type (Fe(1-x)Mn(x))3Al in order to investigate their local magnetic moments. The analysis of the spectra shows that Fe has moments much larger than Mn, whose moment is ferromagnetically coupled with the Fe one. This does not lend support to the antiferromagnetic mechanism proposed for the reduction in magnetization as well as a large Mn moment predicted for x = 1/3. The evolution of satellites found in the Mn spectrum with x increased suggests that the change in the electronic state may result in the magnetization reduction.

15.
J Synchrotron Radiat ; 8(Pt 2): 457-9, 2001 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-11512813

RESUMO

Magnetic circular dichroism (MCD) spectra have been measured at the Fe and V L2,3 edges of DO3-type (Fe(1-x)Vx)3Al in order to investigate their local magnetic moments and electronic structures. Large MCD is observed at the Fe L2,3 edges, while the V L2,3 MCD shows relatively small intensity with complicated features. Signs of these MCD spectra indicate an antiferromagnetic coupling between the magnetic moments on Fe and V. According to the analysis based on the magneto-optical sum rules, the magnetic moment decreases with x, but remains fairly large for Fe2VAl, which might arise from its marginally magnetic nature.

17.
Mol Gen Genet ; 264(5): 539-45, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11212908

RESUMO

The complete sequence of the mitochondrial DNA (mtDNA) of the true slime mold Physarun polycephalum has been determined. The mtDNA is a circular 62,862-bp molecule with an A+T content of 74.1%. A search with the program BLAST X identified the protein-coding regions. The mitochondrial genome of P. polycephalum was predicted to contain genes coding for 12 known proteins [for three cytochrome c oxidase subunits, apocytochrome b, two F1Fo-ATPase subunits, five NADH dehydrogenase (nad) subunits, and one ribosomal protein], two rRNA genes, and five tRNA genes. However, the predicted ORFs are not all in the same frame, because mitochondrial RNA in P. polycephalum undergoes RNA editing to produce functional RNAs. The nucleotide sequence of an nad7 cDNA showed that 51 nucleotides were inserted at 46 sites in the mRNA. No guide RNA-like sequences were observed in the mtDNA of P. polycephalum. Comparison with reported Physarum mtDNA sequences suggested that sites of RNA editing vary among strains. In the Physarum mtDNA, 20 ORFs of over 300 nucleotides were found and ORFs 14 19 are transcribed.


Assuntos
DNA Mitocondrial/genética , Genoma , Fases de Leitura Aberta , Physarum polycephalum/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Northern Blotting , Mapeamento Cromossômico , Clonagem Molecular , DNA Complementar/metabolismo , Dados de Sequência Molecular , Physarum polycephalum/química , Mapeamento Físico do Cromossomo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA , Homologia de Sequência do Ácido Nucleico
18.
Artigo em Inglês | MEDLINE | ID: mdl-11088599

RESUMO

The Coulomb energy of aperiodic systems was investigated. To treat completely isolated disorder in infinite systems, energy correction for a supercell method is presented. We discuss a definition of the correction term, and then consider a direct approach taking into account interactions between charge distribution and an indirect approach based on a multipole expansion. In test calculations for isotropic-charged, anisotropic-charged, and neutral impurities, impurity energies independent of supercell sizes were obtained. The present energy correction can be applied to arbitrary systems and is expected to realize more practical simulations for aperiodic systems.

19.
Mol Phylogenet Evol ; 17(2): 256-68, 2000 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11083939

RESUMO

A combined data set of DNA sequences (6021 bp) from five protein-coding genes of the chloroplast genome (rbcL, atpB, psaA, psaB, and psbC genes) were analyzed for 42 strains representing 30 species of the colonial Volvocales (Volvox and its relatives) and 5 related species of green algae to deduce robust phylogenetic relationships within the colonial green flagellates. The 4-celled family Tetrabaenaceae was robustly resolved as the most basal group within the colonial Volvocales. The sequence data also suggested that all five volvocacean genera with 32 or more cells in a vegetative colony (all four of the anisogamous/oogamous genera, Eudorina, Platydorina, Pleodorina, and Volvox, plus the isogamous genus Yamagishiella) constituted a large monophyletic group, in which 2 Pleodorina species were positioned distally to 3 species of Volvox. Therefore, most of the evolution of the colonial Volvocales appears to constitute a gradual progression in colonial complexity and in types of sexual reproduction, as in the traditional volvocine lineage hypothesis, although reverse evolution must be considered for the origin of certain species of Pleodorina. Data presented here also provide robust support for a monophyletic family Goniaceae consisting of two genera: Gonium and Astrephomene.


Assuntos
Clorófitas/genética , DNA de Cloroplastos/genética , Evolução Molecular , Complexo de Proteína do Fotossistema I , Proteínas de Algas/genética , Proteínas de Bactérias/genética , Clorófitas/classificação , DNA de Cloroplastos/química , DNA Intergênico/genética , Íntrons/genética , Proteínas de Membrana/genética , Dados de Sequência Molecular , Complexo de Proteínas do Centro de Reação Fotossintética/genética , Filogenia , Mutação Puntual , ATPases Translocadoras de Prótons/genética , Ribulose-Bifosfato Carboxilase/genética , Análise de Sequência de DNA
20.
Phytochemistry ; 55(1): 1-9, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11021637

RESUMO

The expression of alpha-amylase in aleurone layers of barley is known to be induced by gibberellin A3 (GA). In the present study, gibbestatin B (GNB) was isolated from Streptomyces sp. C-39 as an inhibitor of the GA-induced expression of alpha-amylase in barley and rice, with IC50 values of 125 and 70 microM, respectively. GNB suppressed accumulation of GA-induced barley high-pI type B and rice RAmylA alpha-amylase transcripts. However, GNB showed no inhibitory activity on GUS expression in transgenic tobacco harboring the auxin-inducible par B promoter:: GUS fusion gene. The transcription of an abscisic acid (ABA)-inducible gene, HVA1, was unaffected by GNB. In addition, GNB prevented aleurone cells from cell death induced by GA. In tobacco and Arabidopsis plants, GNB suppressed the germination and retarded the growth of seedlings without toxicity. The growth of gai, spy and abi mutants was also retarded by GNB. Normal plants treated with GA-biosynthesis inhibitors and GA-defective and GA-signaling mutants normally have dwarf dark green leaves. However, dwarfed healthy green leaves were observed in normal plants treated with GNB. GA-induced stem elongation of plants was also detected in the presence of GNB. These analyses indicate that GNB inhibits the GA-induced expression of alpha-amylase by regulating one of the steps involved in ABA signaling, but not by acting as a weak ABA analog.


Assuntos
Compostos de Epóxi/farmacologia , Giberelinas/metabolismo , Hordeum/enzimologia , Oryza/enzimologia , Fenilacetatos/farmacologia , alfa-Amilases/metabolismo , Ácido Abscísico/fisiologia , Morte Celular/fisiologia , Regulação Enzimológica da Expressão Gênica/fisiologia , Regulação da Expressão Gênica de Plantas/fisiologia , Giberelinas/antagonistas & inibidores , Ácidos Indolacéticos/fisiologia , alfa-Amilases/genética
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