RESUMO
BACKGROUND: Platinum-based chemoradiation (CCRT) is the standard treatment for Locally Advanced Head and Neck Squamous-Cell Carcinoma (LAHNSCC). Cetuximab/RT (CET/RT) is an alternative treatment option to CCRT. The efficacy of induction chemotherapy (IC) followed by chemoradiation compared to chemoradiation alone has not been demonstrated in randomized clinical trials. The goals of this phase II-III trial were to assess: (i) the overall survival (OS) of IC versus no-induction (no-IC) and (ii) the Grade 3-4 in-field mucosal toxicity of CCRT versus CET/RT. The present paper focuses on the analysis of efficacy. MATERIALS AND METHODS: Patients with LAHNSCC were randomized to receive concomitant treatment alone [CCRT (Arm A1) or CET/RT (Arm A2)], or three cycles of induction docetaxel/cisplatin/5 fluorouracil (TPF) followed by CCRT (Arm B1) or followed by CET/RT (Arm B2). The superiority hypothesis of OS comparison of IC versus no-IC (Arms B1 + B2 versus A1 + A2) required 204 deaths to detect an absolute 3-year OS difference of 12% (HR 0.675, with 80% power at two-sided 5% significance level). RESULTS: 414 out of 421 patients were finally analyzed: 206 in the IC and 208 in the no-IC arm. Six patients were excluded because of major violation and one because of metastatic disease at diagnosis. With a median follow-up of 44.8 months, OS was significantly higher in the IC arm (HR 0.74; 95% CI 0.56-0.97; P = 0.031). Complete Responses (P = 0.0028), Progression Free Survival (P = 0.013) and the Loco-regional Control (P = 0.036) were also significantly higher in the IC arm. Compliance to concomitant treatments was not affected by induction TPF. CONCLUSIONS: IC followed by concomitant treatment improved the outcome of patients with LAHNSCC without compromising compliance to the concomitant treatments. The degree of the benefit of IC could be different according to the type of the subsequent concomitant strategy. CLINICAL TRIAL NUMBER: NCT01086826, www.clinicaltrials.gov.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Carcinoma de Células Escamosas/terapia , Neoplasias de Cabeça e Pescoço/terapia , Quimioterapia de Indução , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Células Escamosas/patologia , Quimiorradioterapia , Cisplatino/administração & dosagem , Feminino , Fluoruracila/administração & dosagem , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Carcinoma de Células Escamosas de Cabeça e Pescoço , Análise de Sobrevida , Taxoides/administração & dosagemRESUMO
Bacillus subtilis bacteriophage SPP-I has separable complementary DNA strands. Fragments of nascent DNA isolated a very short time after phage infection show that these short chains are complementary to both phage DNA strands, as observed by hybridization techniques.
Assuntos
Bacteriófagos , Replicação do DNA , DNA Viral/isolamento & purificação , Bacillus subtilis , DNA Bacteriano , Hibridização Genética , Timidina/metabolismo , TrítioRESUMO
The synthesis of nucleases and proteins specific for competence development have been studied in four different Bacillus subtilis competence-deficient mutants. The nuclease analysis showed that two DNA-binding-deficient mutants were impaired in three nuclease activities involved in binding and entry of donor DNA. The other two strains did not show any reduction in nuclease activities. Two-dimensional gel electrophoresis of the proteins, synthesized during competence development, revealed that all four mutants are lacking several competence-specific polypeptides. Our data show that these com mutations have a strong pleiotropic effect, which could be due to a block in the metabolic pathway leading to competence development.
Assuntos
Bacillus subtilis/genética , Proteínas de Bactérias/genética , Desoxirribonucleases/genética , Mutação , Bacillus subtilis/metabolismo , Proteínas de Bactérias/isolamento & purificação , Membrana Celular/metabolismo , Proteínas de Ligação a DNA/genética , Desoxirribonucleases/isolamento & purificação , Eletroforese em Gel de PoliacrilamidaRESUMO
The HIS6 gene from Saccharomyces cerevisiae strain YNN282 is able to complement both the S. cerevisiae his6 and the Escherichia coli hisA mutations. The cloning and the nucleotide sequence indicated that this gene encodes a putative phosphoribosyl-5-amino-1-phosphoribosyl-4-imidazolecarboxiamide isomerase (5' Pro-FAR isomerase, EC 5.3.1.16) of 261 amino acids, with a molecular weight of 29,554. The HIS6 gene product shares a significant degree of sequence similarity with the prokaryotic HisA proteins and HisF proteins, and with the C-terminal domain of the S. cerevisiae HIS7 protein (homologous to HisF), indicating that the yeast HIS6 and HIS7 genes are paralogous. Moreover, the HIS6 gene is organized into two homologous modules half the size of the entire gene, typical of all the known prokaryotic hisA and hisF genes. The structure of the yeast HIS6 gene supports the two-step evolutionary model suggested by Fani et al. (J. Mol. Evol. 1994; 38: 489-495) to explain the present-day hisA and hisF genes. According to this idea, the hisF gene originated from the duplication of an ancestral hisA gene which, in turn, was the result of an earlier gene elongation event involving an ancestral module half the size of the extant gene. Results reported in this paper also suggest that these two successive paralogous gene duplications took probably place in the early steps of molecular evolution of the histidine pathway, well before the diversification of the three domains, and that this pathway was one of the metabolic activities of the last common ancestor. The molecular evolution of the yeast HIS6 and HIS7 genes is also discussed.
Assuntos
Aldose-Cetose Isomerases/genética , Evolução Molecular , Genes Fúngicos/genética , Histidina/biossíntese , Saccharomyces cerevisiae/genética , Sequência de Aminoácidos , Aminoidrolases/genética , Sequência de Bases , Clonagem Molecular , Dados de Sequência Molecular , Complexos Multienzimáticos/genética , Filogenia , Mapeamento por Restrição , Saccharomyces cerevisiae/enzimologia , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Transferases/genéticaRESUMO
There is still a lack of agreement concerning the relative contribution of wine yeast that may originate in the vineyard compared to that which may originate in the cellar. Part of this controversy is due to the extreme difficulty of finding Saccharomyces cerevisiae on the grapes. We estimate that only about one in one-thousand grape berries carries wine yeast. However, we have found that grape berries that are damaged (i.e. the skin is broken) are very rich depositories of microorganisms including S. cerevisiae, and that one in four such berries is S. cerevisiae-positive. These positive berries have between 100,000 and 1,000,000 wine yeast cells on them, and there is evidence that these yeasts are clonal. We believe that the yeasts are brought to the berries by insects such as bees, wasps, and Drosophila and that they multiply in the rich medium of the grape interior. Even though there are many cells of S. cerevisiae on the damaged berries, they are in a definite minority. All the other organisms that are found in wine fermentations are also present on these berries, and their total numbers are in the range of 10 million to 100 million cells per berry.
Assuntos
Rosales/microbiologia , Saccharomyces cerevisiae/isolamento & purificação , Vinho/microbiologia , Animais , Fermentação , Insetos/microbiologia , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimentoRESUMO
The effects of ten fungicides, six herbicides and four insecticides on the nitrogen-fixing bacterium Azospirillum brasilense were examined. The fungicides captan and thiram were the most toxic among the compounds tested. Cell growth and nitrogenase activity of the bacterium were markedly inhibited by low concentrations of the two fungicides. Antidote 1,8-naphthalic anhydride increased by a factor of 2 the cellular level of glutathione. The addition of the antidote in the presence of captan or thiram caused a similar increase in the glutathione content, but at the same time enhanced the toxicity of the two fungicides.
Assuntos
Azospirillum brasilense/efeitos dos fármacos , Captana/farmacologia , Naftalenos/farmacologia , Fixação de Nitrogênio/efeitos dos fármacos , Tiram/farmacologia , Azospirillum brasilense/crescimento & desenvolvimento , Depressão Química , Fungicidas Industriais/farmacologia , Glutationa/análise , Glutationa/metabolismo , Herbicidas/farmacologia , Técnicas In Vitro , Inseticidas/farmacologiaRESUMO
Restriction endonuclease analysis was used as a new method to obtain genomic DNA fingerprints in yeast. Fifteen yeast strains belonging to the genera Saccharomyces and Zygosaccharomyces were examined. Restriction fragments obtained with ApaI or KspI endonucleases were separated by SDS-PAGE and silver-stained. Analysis of the fingerprints showed that restriction enzyme digestion of genomic DNA can be successfully applied to yeast, enabling the differentiation between strains belonging to different or to the same species or genera.
Assuntos
Impressões Digitais de DNA/métodos , DNA Fúngico/análise , Saccharomyces/classificação , DNA Fúngico/genética , Eletroforese em Gel de Poliacrilamida , Técnicas In Vitro , Mapeamento por Restrição , Saccharomyces/genéticaRESUMO
Random amplified polymorphic DNA (RAPD) analysis was applied to genomic DNA from nineteen yeast strains belonging to the genera Saccharomyces and Zygosaccharomyces. Results obtained with five primers indicated that this technique is a powerful tool for yeast differentiation and identification. The data were consistent with those derived from restriction fragment length polymorphism (RFLP) using two S. cerevisiae DNA probes. We conclude that RAPD fingerprinting, combined with the analysis of RFLP, can provide unambiguous type assignment in yeasts.
Assuntos
DNA Bacteriano/química , Polimorfismo de Fragmento de Restrição , Técnica de Amplificação ao Acaso de DNA Polimórfico , Saccharomyces/classificação , DNA Bacteriano/genética , Eletroforese em Gel de Ágar , Técnicas In Vitro , Polimorfismo Genético , Saccharomyces/genética , Saccharomyces/isolamento & purificaçãoRESUMO
Eighteen mutants resistant to 5',5',5'-trifluoroleucine (TFL), a leucine analog, were isolated in Saccharomyces cerevisiae strains YNN281 and YNN282. The mutants were characterized genetically and clustered in two groups, one comprising all the dominant (TFL1) and the other one all the recessive (tfl2) mutations. Genetic and biochemical data suggested that the dominant mutations are located on the LEU4 gene, coding for alpha-isopropylmalate synthase I. These mutations resulted in accumulation of leucine as a consequence of the synthesis of an enzyme insensitive to the feedback inhibition by leucine. Leucine excretion in the TFL1 mutants appeared to be affected by the genetic background of the strain and was greatly influenced by lysine metabolism. The measurement of intra- and extracellular amino acid concentrations in prototrophic strains carrying TFL1 or tfl2 genes showed that both were leucine overproducers. Some of the TFL-resistant mutants were tested in alcoholic fermentation of grape must: analysis of the fermentation secondary metabolites showed that the major effect of the TFL-resistant strains was an increased production of isoamyl alcohol compared to that of the parental strain.
Assuntos
Genes Fúngicos/genética , Glicogênio Sintase/metabolismo , Leucina/análogos & derivados , Pentanóis/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Mapeamento Cromossômico , Resistência Microbiana a Medicamentos/genética , Retroalimentação , Fermentação , Genótipo , Leucina/metabolismo , Lisina/metabolismo , Fenótipo , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/isolamento & purificaçãoRESUMO
A 3457-base pair fragment of Azospirillum brasilense DNA which complemented mutations in the hisA and hisF genes of Escherichia coli was sequenced. The sequence analysis revealed the presence of six major contiguous open reading frames (ORF). The comparison of the predicted amino acid sequence of these ORF with those encoded by the eubacterial, archaebacterial and eukaryotic his genes sequenced thus far revealed that four of them have a significant degree of homology with the E. coli hisH, hisA, hisF and the C-terminal domain of the hisI gene products. S1 mapping experiments indicated that the putative transcription start site coincided with the AUG translational initiation codon of the hisBd gene, the first gene of the A. brasilense his operon. Downstream from the last ORF, a sequence was identified which functions as a Rho-independent transcription terminator. Comparison of amino acid sequences, gene order and organization and evolutionary aspects of the A. brasilense his cluster are discussed.
Assuntos
Azospirillum brasilense/genética , Histidina/genética , Óperon/genética , Sequência de Aminoácidos/genética , Proteínas de Bactérias/genética , Sequência de Bases/genética , Eletroforese em Gel de Poliacrilamida , Escherichia coli/genética , Técnicas In Vitro , Dados de Sequência Molecular , Fases de Leitura Aberta/genética , Transcrição GênicaRESUMO
Eighty-six strains of Saccharomyces cerevisiae were investigated for their ability to produce acetaldehyde in synthetic medium and in grape must. Acetaldehyde production did not differ significantly between the two media, ranging from a few mg/l to about 60 mg/l, and was found to be a strain characteristic. The fermentation temperature of 30 degrees C considerably increased the acetaldehyde produced. This study allowed us to assign the strains to different phenotypes: low, medium and high acetaldehyde producers. The low and high phenotypes differed considerably also in the production of acetic acid, acetoin and higher alcohols and can be useful for studying acetaldehyde production in S. cerevisiae, both from the technological and genetic point of view.
Assuntos
Acetaldeído/metabolismo , Fermentação/fisiologia , Saccharomyces cerevisiae/metabolismo , Vinho , Acetatos/metabolismo , Ácido Acético , Acetoína/metabolismo , Álcoois/metabolismo , Meios de Cultura , Temperatura Alta , Especificidade da EspécieRESUMO
The resistance to 5,5,5-trifluoro-DL-leucine, encoded by the dominant allele LEU4-1, was used as a selectable marker to transform laboratory and natural Saccharomyces cerevisiae strains by the lithium acetate procedure. Results of transformation of S. cerevisiae laboratory and wine natural strains showed that trifluoroleucine resistance is a very effective selection marker and can be widely used to transform prototrophic S. cerevisiae strains. The LEU4-1 gene could also be exploited to improve wine flavour, as indicated by the higher isoamyl alcohol content of the transformants compared to the parental strains.
Assuntos
Leucina/análogos & derivados , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/efeitos dos fármacos , Transformação Genética , 2-Isopropilmalato Sintase/genética , Resistência Microbiana a Medicamentos/genética , Fermentação , Proteínas Fúngicas/genética , Genes Dominantes , Marcadores Genéticos , Leucina/metabolismo , Leucina/farmacologia , Pentanóis/metabolismo , Plasmídeos/genética , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Vinho/microbiologiaRESUMO
The dihydrofolate reductase gene from Candida albicans has been cloned and partially characterized. A genomic bank from C. albicans strain 10127/5 was constructed in Escherichia coli and screened for trimethoprim resistance. A plasmid pMF1, carrying the resistance marker was isolated and characterized by restriction mapping and Southern blotting. Cells harbouring pMF1 were as sensitive as the parental cells to a wide spectrum of antibacterial agents, except for trimethoprim; the dihydrofolate reductase activity from these cells was trimethoprim resistant.
Assuntos
Candida albicans/genética , Clonagem Molecular , Tetra-Hidrofolato Desidrogenase/genética , Resistência Microbiana a Medicamentos/genética , Plasmídeos , Trimetoprima/farmacologiaRESUMO
The electronic and 1H NMR spectra are reported for the cobalt(II) alkaline phosphatase (EC 3.1.3.1.) system at pH around 6 in the range 0-2 mol of cobalt per mol protein. It is shown that under the present experimental conditions cobalt(II) selectively populates the A sites. Three isotropically shifted NH signals have been detected in the A site that indicate the presence of three histidines in the coordination sphere of cobalt(II). The electronic spectra and the nuclear relaxation properties are consistent with pentacoordination of cobalt(II) in the A site. The finding of reproducible preparation routes for the derivatives, and of appropriate experimental conditions for the observation of their 1H NMR spectra, open new possibilities for the spectroscopic investigation of alkaline phosphatase.
Assuntos
Fosfatase Alcalina/metabolismo , Cobalto/metabolismo , Escherichia coli/enzimologia , Espectroscopia de Ressonância Magnética , Ligação Proteica , EspectrofotometriaRESUMO
The Ugi four-component condensation between isocyanides 1, cycloketones 2, and ammonium formate affords N-substituted formylaminocarboxamides 3 which are dehydrated with POCl3/NEt3 to give the title compounds 4. The structure of the compounds 3 and 4 was confirmed by spectral data and elemental analyses. In vitro tests of antibacterial activity showed that compounds 4 are ineffective against E. coli and fairly active against K. pneumoniae, B. subtilis and S. aureus. A very good antimicotic activity was shown against C. albicans.
Assuntos
Amidas/síntese química , Anti-Infecciosos/síntese química , Nitrilas/síntese química , Amidas/farmacologia , Antibacterianos , Anti-Infecciosos/farmacologia , Bactérias/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Nitrilas/farmacologia , Espectrofotometria Infravermelho , Relação Estrutura-AtividadeAssuntos
Bacillus subtilis , RNA Bacteriano , Receptores de Droga , Ribossomos , Estreptomicina , Centrifugação com Gradiente de Concentração , Meios de Cultura , DNA Bacteriano , Resistência Microbiana a Medicamentos , Código Genético , Genética Microbiana , Hibridização Genética , Mutação , Desnaturação de Ácido Nucleico , Isótopos de Fósforo , Ribonucleases , Transformação GenéticaAssuntos
Bacteriófagos/análise , DNA Viral/análise , Bacillus subtilis , Bacteriófagos/isolamento & purificação , Bacteriófagos/patogenicidade , Sequência de Bases , Centrifugação com Gradiente de Concentração , Meios de Cultura , DNA Viral/isolamento & purificação , Microscopia Eletrônica , Peso Molecular , Desnaturação de Ácido Nucleico , Renaturação de Ácido Nucleico , Isótopos de Fósforo , RNA Ribossômico/análiseRESUMO
Saccharomyces cerevisiae as model system was used to evaluate the occurrence of resistant mutants and adaptation mechanism to mancozeb (MZ), a widespread fungicide of the dithiocarbamate class with a broad spectrum of action and multiple cell targets. We were unable to isolate mutants resistant to inhibitory concentration of MZ but found an unusually large number of mitochondrial defective petite mutants among cells incubated in the presence of subinhibitory MZ concentration. Similar results were obtained with two other dithiocarbamate fungicides. Comparison of wild type and petite mutants showed that the latter were more resistant to toxic effects of MZ, highlighting the role of mitochondria in MZ-tolerance. The data suggest that petite cells, arising by exposure to sub-inhibitory MZ concentration, are not induced by fungicides but are spontaneous mutants already present in the population before the contact with the fungicide.
Assuntos
Fungicidas Industriais/farmacologia , Maneb/farmacologia , Saccharomyces cerevisiae/efeitos dos fármacos , Tiocarbamatos/farmacologia , Zineb/farmacologia , Farmacorresistência Fúngica , Tolerância a Medicamentos , Mitocôndrias/metabolismo , Mutação , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismoAssuntos
Antioxidantes/metabolismo , Carotenoides/sangue , Dieta , Frutas , Verduras , Idoso , Biomarcadores/sangue , Registros de Dieta , Comportamento Alimentar , Feminino , Humanos , Pessoa de Meia-Idade , Saúde da MulherRESUMO
Polsinelli, M. (University of Pavia, Pavia, Italy), and Maria Beretta. Genetic recombination in crosses between Streptomyces aureofaciens and Streptomyces rimosus. J. Bacteriol. 91:63-68. 1966.-Biochemical mutants were obtained from Streptomyces rimosus and S. aureofaciens by ultraviolet irradiation. Crosses were performed between auxotrophic strains of S. rimosus and S. aureofaciens with positive results. Data are reported which indicate that the interaction observed in some crosses is due to gene recombination.