Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 30
Filtrar
1.
Phys Rev Lett ; 116(21): 214801, 2016 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-27284661

RESUMO

The Polarized Electrons for Polarized Positrons experiment at the injector of the Continuous Electron Beam Accelerator Facility has demonstrated for the first time the efficient transfer of polarization from electrons to positrons produced by the polarized bremsstrahlung radiation induced by a polarized electron beam in a high-Z target. Positron polarization up to 82% have been measured for an initial electron beam momentum of 8.19 MeV/c, limited only by the electron beam polarization. This technique extends polarized positron capabilities from GeV to MeV electron beams, and opens access to polarized positron beam physics to a wide community.

2.
Sci Total Environ ; 745: 141285, 2020 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-32943215

RESUMO

During water years (WY) 2013-2017, the U.S. Geological Survey, National Water-Quality Assessment (NAWQA) Project, sampled the National Water Quality Network - Rivers and Streams (NWQN) year-round and reported on 221 pesticides at 72 sites across the United States in agricultural, developed, and mixed land use watersheds. The Pesticide Toxicity Index (PTI) was used to estimate the potential chronic and acute toxicity to three taxonomic groups - fish, cladocerans, and benthic invertebrates. For invertebrates (either cladocerans, benthic invertebrates, or both), the maximum PTI score exceeded the predicted acute toxicity screening level at 18 of the 72 sites (25%) at some point during WY 2013-2017. The predicted toxicity of a single pesticide compound was found to overwhelm the toxicity of other pesticides in the mixtures after concentrations were toxicity weighted. For this study, about 71%, 72%, and 92% of the Fish-, Cladoceran-, and Benthic Invertebrate-PTI scores, respectively, had one pesticide compound primarily contributing to sample potential toxicity (>50%). There were 17 (13 insecticides, 2 herbicides, 1 fungicide, and 1 synergist) of the 221 pesticide compounds analyzed that were the primary drivers of potential toxicity in each water sample in which the PTI and TUmax (toxic unit score for the pesticide that makes the single largest contribution to the PTI) scores were above predicted chronic (>0.1) or acute (>1) toxicity levels for one of the three taxa. For cladocerans and benthic invertebrates, the drivers of predicted chronic (>0.1) and acute (>1) PTIs were mostly insecticides. For cladocerans, the pesticide compounds driving the PTI scores were bifenthrin, carbaryl, chlorpyrifos, diazinon, dichlorvos, dicrotophos, diflubenzuron, flubendiamide, and tebupirimfos. For benthic invertebrates, atrazine (an herbicide), as well as the insecticides - bifenthrin, carbaryl, carbofuran, chlorpyrifos, diazinon, dichlorvos, fipronil, imidacloprid, and methamidophos - were the drivers of predicted toxicity. For fish, there were three pesticide types that contributed the most to predicted chronic (>0.1) PTIs - acetochlor, an herbicide; carbendazim, a fungicide degradate; and piperonylbutoxide, a synergist.


Assuntos
Praguicidas/análise , Praguicidas/toxicidade , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade , Animais , Monitoramento Ambiental , Rios , Estados Unidos , Água
3.
Science ; 254(5039): 1773-6, 1991 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-1763326

RESUMO

A family of cytochrome P-450 (Pda) genes in the pathogenic fungus Nectria haematococca is responsible for the detoxification of the phytoalexin pisatin, an antimicrobial compound produced by garden pea (Pisum sativum L.). The Pda6 gene was mapped by electrophoretic karyotype analysis to a small meiotically unstable chromosome that is dispensable for normal growth. Such traits are typical of B chromosomes. The strains of Nectria studied here have no sequences that are homologous to the Pda family other than Pda6 and therefore demonstrate that unique, functional genes can be found on B chromosomes. Unstable B chromosomes may be one mechanism for generating pathogenic variation in fungi.


Assuntos
Cromossomos Fúngicos , Sistema Enzimático do Citocromo P-450/genética , Resistência Microbiana a Medicamentos/genética , Genes Fúngicos , Hypocreales/genética , Pterocarpanos , Benzopiranos/metabolismo , Mapeamento Cromossômico , Cruzamentos Genéticos , Fabaceae , Cariotipagem , Fenótipo , Plantas Medicinais
4.
Genetics ; 155(3): 1083-94, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10880471

RESUMO

Certain isolates of the plant pathogenic fungus Nectria haematococca mating population (MP) VI contain a 1.6-Mb conditionally dispensable (CD) chromosome carrying the phytoalexin detoxification genes MAK1 and PDA6-1. This chromosome is structurally unstable during sexual reproduction. As a first step in our analysis of the mechanisms underlying this chromosomal instability, hybridization between overlapping cosmid clones was used to construct a map of the MAK1 PDA6-1 chromosome. The map consists of 33 probes that are linked by 199 cosmid clones. The polymerase chain reaction and Southern analysis of N. haematococca MP VI DNA digested with infrequently cutting restriction enzymes were used to close gaps and order the hybridization-derived contigs. Hybridization to a probe extended from telomeric repeats was used to anchor the ends of the map to the actual chromosome ends. The resulting map is estimated to cover 95% of the MAK1 PDA6-1 chromosome and is composed of two ordered contigs. Thirty-eight percent of the clones in the minimal map are known to contain repeated DNA sequences. Three dispersed repeats were cloned during map construction; each is present in five to seven copies on the chromosome. The cosmid clones representing the map were probed with deleted forms of the CD chromosome and the results were integrated into the map. This allowed the identification of chromosome breakpoints and deletions.


Assuntos
Ascomicetos/genética , Quebra Cromossômica/genética , Cromossomos Fúngicos/genética , Mapeamento Físico do Cromossomo/métodos , Southern Blotting , Células Clonais , Clonagem Molecular , Hibridização de Ácido Nucleico , Reação em Cadeia da Polimerase , Sequências Repetitivas de Ácido Nucleico/genética , Análise de Sequência de DNA
5.
Genetics ; 157(3): 979-90, 2001 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11238388

RESUMO

A Neurospora crassa cosmid library of 12,000 clones (at least nine genome equivalents) has been created using an improved cosmid vector pLorist6Xh, which contains a bacteriophage lambda origin of replication for low-copy-number replication in bacteria and the hygromycin phosphotransferase marker for direct selection in fungi. The electrophoretic karyotype of the seven chromosomes comprising the 42.9-Mb N. crassa genome was resolved using two translocation strains. Using gel-purified chromosomal DNAs as probes against the new cosmid library and the commonly used medium-copy-number pMOcosX N. crassa cosmid library in two independent screenings, the cosmids were assigned to chromosomes. Assignments of cosmids to linkage groups on the basis of the genetic map vs. the electrophoretic karyotype are 93 +/- 3% concordant. The size of each chromosome-specific subcollection of cosmids was found to be linearly proportional to the size of the particular chromosome. Sequencing of an entire cosmid containing the qa gene cluster indicated a gene density of 1 gene per 4 kbp; by extrapolation, 11,000 genes would be expected to be present in the N. crassa genome. By hybridizing 79 nonoverlapping cosmids with an average insert size of 34 kbp against cDNA arrays, the density of previously characterized expressed sequence tags (ESTs) was found to be slightly <1 per cosmid (i.e., 1 per 40 kbp), and most cosmids, on average, contained an identified N. crassa gene sequence as a starting point for gene identification.


Assuntos
Cromossomos/genética , Cosmídeos/genética , Biblioteca Gênica , Genoma Fúngico , Neurospora crassa/genética , Bacteriófago lambda/genética , Mapeamento Cromossômico , DNA Complementar/genética , DNA Complementar/metabolismo , Etiquetas de Sequências Expressas , Ligação Genética , Vetores Genéticos , Cariotipagem , Modelos Genéticos , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Mapeamento Físico do Cromossomo , Análise de Sequência de DNA
6.
Mol Plant Microbe Interact ; 10(6): 742-9, 1997 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-9245836

RESUMO

Certain isolates of the plant-pathogenic fungus Nectria haematococca mating population VI (MPVI) contain dispensable chromosomes that are unstable during sexual reproduction. Several of these chromosomes carry genes for phytoalexin detoxification and thus contribute to the pathogenic potential of this organism. A repeated DNA sequence, Nht1, was cloned from one of these dispensable chromosomes in N. haematococca MPVI. One copy of the repeated element (Nht1A) was completely sequenced. It is 2,198 bp long and it possesses incomplete inverted terminal repeats (ITRs) at each end. Nht1B, a partially sequenced copy of Nht1, has complete ITRs. Nht1A appears to contain 2 introns and encodes a protein of 550 amino acids that is highly similar to the protein encoded by the Fusarium oxysporum transposon, Fot1. Due to the presence of ITRs, its repeated nature, and its similarity to Fot1, we conclude that Nht1 is a transposable element. Within North American N. Haematococca MPVI populations, Nht1 is distributed discontinuously. Its copy number in different field isolates varies from zero to approximately 100 copies per genome. The Nht1A source isolate is estimated to contain nine to 11 copies of Nht1; at least six are on the chromosome from which Nht1A was cloned.


Assuntos
Cromossomos Fúngicos/genética , Elementos de DNA Transponíveis/genética , Hypocreales/genética , Sequência de Aminoácidos , Sequência de Bases , Clonagem Molecular , Geografia , Dados de Sequência Molecular , Doenças das Plantas/microbiologia , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Estados Unidos
7.
Gene ; 79(1): 97-106, 1989 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-2673937

RESUMO

A cDNA library was constructed in the yeast expression vector pYcDE8 using mRNA from the phytopathogenic fungus Ustilago maydis and cDNAs capable of complementing mutations in three yeast genes, URA3, LEU2 and TPI1, were identified. Nucleotide sequence analysis indicated that the cDNA clone, which complemented the yeast ura3 mutation, carries the pyr6 gene encoding orotidine-5'-phosphate decarboxylase. The genomic copy of the pyr6 gene was isolated by hybridization with the cDNA and used to complement a pyr- mutant of U. maydis. One-step gene disruption was demonstrated by transforming U. maydis with a copy of the pyr6 gene interrupted in the coding region by a selectable marker for resistance to hygromycin B.


Assuntos
Basidiomycota/genética , Carboxiliases/genética , Genes Fúngicos , Orotidina-5'-Fosfato Descarboxilase/genética , Ustilago/genética , Sequência de Aminoácidos , Sequência de Bases , Clonagem Molecular , DNA Fúngico , Resistência Microbiana a Medicamentos/genética , Escherichia coli/genética , Teste de Complementação Genética , Marcadores Genéticos , Higromicina B/farmacologia , Dados de Sequência Molecular , Mutação , Plasmídeos , Transformação Genética
8.
Am J Med Genet ; 103(3): 193-7, 2001 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-11745990

RESUMO

We describe two cases in which a minute supernumerary marker chromosome (SMC) was identified in addition to a larger pseudodicentric chromosome. Case 1, a phenotypically normal male, had mosaicism for a psu dic(15;15)(q11.2;q11.2) chromosome and a minute SMC. Fluorescence in situ hybridization (FISH) showed that the minute SMC was D15Z1 positive, indicating a chromosome 15 origin. Case 2 was a 22-week fetus with mosaicism for a normal and two abnormal cell lines: one had a psu dic (22;22)(q11.2;q11.2) chromosome containing euchromatin, usually associated with cat eye syndrome; the other a minute SMC. The minute SMC was positive with the D14Z1/D22Z1 alpha-satellite probe, indicating a chromosome 14 or chromosome 22 origin. Deletion of centromeric material was proposed as one mechanism of centromere inactivation in dicentric chromosomes. The origin of these two minute SMC suggests that they were derived from one of the centromeres of the larger pseudodicentric chromosome. These stable minute SMC may be the by-product of a deletion event inactivating one centromere of a dicentric chromosome to generate a pseudodicentric chromosome. Alternatively, the minute SMC may originate from further rearrangement of the larger pseudodicentric chromosome. These cases suggest possible mechanisms for the origin of minute SMC.


Assuntos
Aberrações Cromossômicas , Cromossomos Humanos Par 15/genética , Cromossomos Humanos Par 22/genética , Marcadores Genéticos/genética , Mosaicismo/genética , Amniocentese , Feminino , Feto , Humanos , Hibridização in Situ Fluorescente , Cariotipagem , Masculino , Pessoa de Meia-Idade , Gravidez
9.
Lipids ; 19(11): 844-50, 1984 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-6521609

RESUMO

The non-lipid portions of semi-synthetic diets appear to be important determinants of hypercholesterolemia and atherosclerosis in the rabbit. Serum and liver lipid concentrations were determined in rabbits which had been pair-fed various protein (casein or soy protein isolate) and carbohydrate (sucrose or dextrose) sources as part of low fat, low cholesterol, semi-synthetic diets. It was verified that casein-containing diets render rabbits hypercholesterolemic, while soy protein caused a degree of hypocholesterolemia. Additionally, sucrose, when fed in conjunction with casein, appears to augment this hypercholesterolemic effect. The distribution of total cholesterol among lipoprotein subclasses was increased in both the intermediate density lipoprotein (IDL) (1.006-1.019 g/ml) and low density lipoprotein (LDL) (1.019-1.063 g/ml) fractions and decreased in the high density lipoprotein (HDL) (1.063-1.21 g/ml) fraction when casein is fed. Soy protein feeding caused relatively more cholesterol to appear only in the IDL fraction when compared with commercial chow fed rabbits. Reasons for these differences may involve the saturation or suppression of endogenous lipoprotein hepatic receptors.


Assuntos
Colesterol/metabolismo , Carboidratos da Dieta/farmacologia , Proteínas Alimentares/farmacologia , Metabolismo dos Lipídeos , Lipoproteínas/metabolismo , Fígado/metabolismo , Animais , Peso Corporal , Ingestão de Energia , Alimentos Formulados , Fosfolipídeos/metabolismo , Coelhos
10.
J Vet Intern Med ; 8(1): 40-8, 1994.
Artigo em Inglês | MEDLINE | ID: mdl-8176662

RESUMO

Two dogs developed delayed neurological deterioration after rapid correction of severe hyponatremia. Sequential magnetic resonance imaging showed the development of lesions in the thalamus. One dog was necropsied, and the lesions were characterized by myelinolysis with sparing of axons and neurons. The second dog gradually recovered with no detectable neurological deficits. The syndrome seems analogous to central pontine myelinolysis in human beings. Guidelines for correction of hyponatremia to prevent development of myelinolysis are given.


Assuntos
Doenças do Cão , Hiponatremia/veterinária , Mielinólise Central da Ponte/veterinária , Cloreto de Sódio/administração & dosagem , Animais , Doenças do Cão/diagnóstico por imagem , Doenças do Cão/tratamento farmacológico , Cães , Feminino , Hiponatremia/complicações , Hiponatremia/diagnóstico por imagem , Hiponatremia/tratamento farmacológico , Masculino , Mielinólise Central da Ponte/diagnóstico por imagem , Mielinólise Central da Ponte/tratamento farmacológico , Mielinólise Central da Ponte/etiologia , Radiografia
11.
Health Phys ; 74(4): 451-5, 1998 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-9525419

RESUMO

Groundwater radon concentration of 83 Bq L(-1) generated indoor radon levels exceeding 3,300 Bq m(-3) at a commercial fish hatchery. Passive and active mitigation strategies to reduce the waterborne radon levels included a packed column, a waterfall through perforated grates, surface aeration, and bottom bubblers. Waterborne concentrations were reduced up to 83% using a combination of mitigation procedures, but a comparable reduction in indoor radon concentrations was not observed. A diurnal cycle showed that indoor radon levels peaked in early afternoon, probably as a result of warmer air being dissolved in the water during mitigation. Reduction of indoor radon levels below 148 Bq m(-3) was seldom achievable with both water mitigation and direct air ventilation at 23 room air changes hourly.


Assuntos
Poluentes Radioativos do Ar/análise , Radônio/análise , Poluentes Radioativos da Água/análise , Animais , Peixes , Humanos , New York , Exposição Ocupacional/prevenção & controle
12.
Biotechnology (N Y) ; 12(13): 1372-5, 1994 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-7765568

RESUMO

Determining linkage is problematic for genes lacking easily identifiable phenotypes and for organisms without well-defined genetic recombination systems. Phanerochaete chrysosporium with its lignin peroxidase (LiP) gene family typifies these difficulties. We describe an experimental approach whereby the segregation of specific alleles is directly monitored during sexual fruiting. The method establishes linkage relationships among genes for which there are no mutations, and it is applicable to a wide range of genes, gene families and organisms. Using this approach, five P. chrysosporium linkage groups were identified. Ten LiP genes were distributed among three of these groups. One co-segregating group contained eight closely linked LiP genes. Another LiP gene was linked to a cellobiohydrolase gene cluster. These genetic linkages were consistent with physical mapping by pulsed field gel electrophoresis. Based on the identification of allelic relationships, a uniform nomenclature for LiP genes is also described.


Assuntos
Alelos , Basidiomycota/genética , Ligação Genética , Peroxidases/genética , Reação em Cadeia da Polimerase , Sequência de Bases , Basidiomycota/enzimologia , Mapeamento Cromossômico , Clonagem Molecular , DNA Fúngico/química , DNA Fúngico/genética , Genes Fúngicos , Dados de Sequência Molecular , Sondas de Oligonucleotídeos , Terminologia como Assunto
14.
Fungal Genet Biol ; 44(8): 799-807, 2007 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-17300967

RESUMO

We investigated the sexual reproductive mode of the two most important etiological agents of soybean sudden death syndrome, Fusarium tucumaniae and Fusarium virguliforme. F. tucumaniae sexual crosses often were highly fertile, making it possible to assign mating type and assess female fertility in 24 South American isolates. These crosses produced red perithecia and oblong-elliptical ascospores, as is typical for sexual members of the F. solani species complex. Genotyping of progeny from three F. tucumaniae crosses confirmed that sexual recombination had occurred. In contrast, pairings among 17 U.S. F. virguliforme isolates never produced perithecia. Inter-species crosses between F. tucumaniae and F. virguliforme, in which infertile perithecia were induced only in one of the two F. tucumaniae mating types, suggest that all U.S. F. virguliforme isolates are of a single mating type. We conclude that the F. tucumaniae life cycle in S. America includes a sexual reproductive mode, and thus this species has greater potential for rapid evolution than the F. virguliforme population in the U.S., which may be exclusively asexual.


Assuntos
Fusarium/crescimento & desenvolvimento , Fusarium/fisiologia , Glycine max/microbiologia , Doenças das Plantas/microbiologia , Cruzamentos Genéticos , DNA Fúngico/genética , Fusarium/ultraestrutura , Genótipo , Microscopia Eletrônica de Varredura , Reação em Cadeia da Polimerase , Esporos Fúngicos/citologia , Esporos Fúngicos/ultraestrutura
15.
Science ; 313(5793): 1596-604, 2006 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-16973872

RESUMO

We report the draft genome of the black cottonwood tree, Populus trichocarpa. Integration of shotgun sequence assembly with genetic mapping enabled chromosome-scale reconstruction of the genome. More than 45,000 putative protein-coding genes were identified. Analysis of the assembled genome revealed a whole-genome duplication event; about 8000 pairs of duplicated genes from that event survived in the Populus genome. A second, older duplication event is indistinguishably coincident with the divergence of the Populus and Arabidopsis lineages. Nucleotide substitution, tandem gene duplication, and gross chromosomal rearrangement appear to proceed substantially more slowly in Populus than in Arabidopsis. Populus has more protein-coding genes than Arabidopsis, ranging on average from 1.4 to 1.6 putative Populus homologs for each Arabidopsis gene. However, the relative frequency of protein domains in the two genomes is similar. Overrepresented exceptions in Populus include genes associated with lignocellulosic wall biosynthesis, meristem development, disease resistance, and metabolite transport.


Assuntos
Duplicação Gênica , Genoma de Planta , Populus/genética , Análise de Sequência de DNA , Arabidopsis/genética , Mapeamento Cromossômico , Biologia Computacional , Evolução Molecular , Etiquetas de Sequências Expressas , Expressão Gênica , Genes de Plantas , Análise de Sequência com Séries de Oligonucleotídeos , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/genética , Polimorfismo de Nucleotídeo Único , Populus/crescimento & desenvolvimento , Populus/metabolismo , Estrutura Terciária de Proteína , RNA de Plantas/análise , RNA não Traduzido/análise
16.
Curr Genet ; 33(5): 311-9, 1998 May.
Artigo em Inglês | MEDLINE | ID: mdl-9618581

RESUMO

Within a fungal species, a subset of individuals may have more than the minimal complement of chromosomes. If the extra chromosomes are composed primarily of DNA not found in all representatives of the species, they are most appropriately referred to as supernumerary chromosomes. The patterns of repeated DNA sequences on certain supernumerary chromosomes suggest that they have a different evolutionary history from the essential chromosomes in the same genome. Supernumerary chromosomes can carry functional genes and, in at least two fungal species, genes on such chromosomes play important roles in host-pathogen interactions. Supernumerary chromosomes that confer an adaptive advantage in certain habitats, such as the ability to cause disease on a specific host, may be referred to as "conditionally dispensable" chromosomes in order to reflect their importance in some, but not all, growth conditions. In addition to describing the structural and functional characteristics of known supernumerary chromosomes in fungi, this review discusses the relative merits of the terms that have been used to describe them, and establishes experimental criteria for their identification.


Assuntos
Cromossomos Fúngicos , Fungos/genética , DNA Fúngico/química , DNA Fúngico/genética , Evolução Molecular , Genoma Fúngico , Doenças das Plantas/microbiologia , Plantas/microbiologia , Sequências Repetitivas de Ácido Nucleico
17.
Appl Environ Microbiol ; 66(12): 5506-8, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11097938

RESUMO

A rapid and reliable mating type assay for Fusarium circinatum was created by applying primers specific for the MAT1-1 and MAT1-2 mating type alleles to genomic DNA in a single PCR. A similar approach may be applied to fungi not previously shown to reproduce sexually, thus enabling studies of population structure and inheritance.


Assuntos
Fusarium/genética , Alelos , Sequência de Bases , Clonagem Molecular , Primers do DNA/genética , DNA Fúngico/genética , Fusarium/fisiologia , Genes Fúngicos , Genes Fúngicos Tipo Acasalamento , Dados de Sequência Molecular
18.
Appl Microbiol ; 28(3): 374-82, 1974 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-4609265

RESUMO

The toxin of Clostridium botulinum type E was isolated from intact cells and from toxic culture filtrates by column chromatography at three pH values, 4.5, 5.3, and 6.0. At pH 6.0 and 5.3, the isolated toxin was in a form with a molecular weight (MW) of 86,000. This toxin was homogeneous on polyacrylamide gel electrophoresis and gel filtration and had an optical density ratio, 280 nm/260 nm, greater than 2.0. It did not dissociate at higher pH levels, but was dissociated into nontoxic components of approximately 12,000 MW when reduced and alkylated in the presence of 6 M guanidine hydrochloride. At pH 4.5, smaller amounts of an impure toxic moiety with a MW of 12,000 were found. After storage for 6 months, the 86,000-MW moiety had lost 60% of its lethality. Gel filtration revealed that the bulk of the toxicity was associated with a component having a MW of 150,000. Toxic components with MW of 12,000 and over 200,000 were also found. The toxin appears to polymerize or aggregate when in a pure form, so that most, if not all, of the MW previously reported for the toxin may belong to different polymers of a monomer with a MW of 12,000 or less. Treatment of the 86,000-MW toxin with trypsin resulted in an 18- to 128-fold increase in lethality, but no detectable change in MW.


Assuntos
Toxinas Botulínicas/análise , Clostridium botulinum/análise , Sulfato de Amônio , Animais , Toxinas Botulínicas/isolamento & purificação , Toxinas Botulínicas/toxicidade , Precipitação Química , Cromatografia em Gel , Cromatografia por Troca Iônica , Estabilidade de Medicamentos , Eletroforese em Gel de Poliacrilamida , Concentração de Íons de Hidrogênio , Injeções Intraperitoneais , Dose Letal Mediana , Camundongos , Peso Molecular , Sorotipagem , Tripsina/farmacologia , Ultracentrifugação
19.
Appl Environ Microbiol ; 59(10): 3492-4, 1993 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-8250570

RESUMO

Previous studies have shown that the cellobiohydrolases of the white rot basidiomycete Phanerochaete chrysosporium are encoded by a family of structurally related genes. In this investigation, we identified and sequenced the most highly transcribed gene, cbh1-4. Evidence suggests that in this fungus the dominant isozyme, CBH1, is encoded by chb1-4.


Assuntos
Basidiomycota/enzimologia , Basidiomycota/genética , Genes Fúngicos , Glicosídeo Hidrolases/genética , Isoenzimas/genética , Sequência de Aminoácidos , Sequência de Bases , Celulose 1,4-beta-Celobiosidase , Primers do DNA , DNA Fúngico/genética , Glicosídeo Hidrolases/química , Ponto Isoelétrico , Dados de Sequência Molecular , Peso Molecular , Transcrição Gênica
20.
Curr Genet ; 22(5): 407-13, 1992 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-1423728

RESUMO

Southern blot and nucleotide sequence analysis of Phanerochaete chrysosporium BKM-F-1767 genomic clones indicate that this wood-degrading fungus contains at least six genes with significant homology to the Trichoderma reesei cellobiohydrolase I gene (cbh1). Using pulsed-field gel electrophoresis to separate P. chrysosporium chromosomes, the six cellulase genes were found to hybridize to at least three different chromosomes, one of which is dimorphic. The organization of these genes was similar in another P. chrysosporium strain, ME 446. It is clear that, unlike T. reesei, the most well-studied cellulolytic fungus, P. chrysosporium contains a complex, cbh1-like gene family.


Assuntos
Basidiomycota/enzimologia , Celulase/genética , Genes Fúngicos , Família Multigênica , Sequência de Aminoácidos , Sequência de Bases , Basidiomycota/genética , Mapeamento Cromossômico , DNA Fúngico , Eletroforese , Dados de Sequência Molecular , Homologia de Sequência do Ácido Nucleico
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA