COCHLIOBOLUS SATIVUS: VI. ISOLATION OF NUTRITIONALLY EXACTING MUTANTS BY FILTRATION ENRICHMENT

1962 ◽  
Vol 40 (10) ◽  
pp. 1293-1297 ◽  
Author(s):  
R. D. Tinline
Keyword(s):  
Mass Transfer ◽  
Comparative Studies ◽  
Minimal Medium ◽  
Cochliobolus Sativus ◽  
Complete Medium ◽  
Differential Growth ◽  
Enrichment Method ◽  
Filtration Enrichment ◽  
Hyphal Tip ◽  
Methods Of Isolation

Nutritionally exacting mutants of Cochliobolus sativus, a fungus with multinucleate, multicellular spores, were readily isolated by a filtration enrichment method. The method is similar to one described by Fries and is based upon the differential growth of auxotrophs and prototrophs in minimal medium. Most of the prototrophic propagules were removed by filtration. Propagules in the filtrate were concentrated by centrifugation, plated on complete medium, and subsequently tested for nutritional requirements.In comparative studies on four methods of isolation, namely, total isolation, mass transfer; total isolation, hyphal-tip transfer; filtration enrichment, mass transfer; and filtration enrichment, hyphal-tip transfer, the yield of auxotrophic mutants was 0, 0.04, 1.16, and 1.83%, respectively.

Detection of Vibrio cholerae and Vibrio parahaemolyticus by molecular and culture based methods from source water to household container-stored water at the point-of-use in South African rural communities

2010 ◽  
Vol 61 (12) ◽  
pp. 3091-3101 ◽  
Author(s):  
V. M. Ntema ◽  
N. Potgieter ◽  
T. G. Barnard
Keyword(s):  
16S Rrna ◽  
Vibrio Cholerae ◽  
Vibrio Parahaemolyticus ◽  
Pcr Detection ◽  
Toxin Gene ◽  
Specific Method ◽  
Culturable Bacteria ◽  
Source Water ◽  
Enrichment Method ◽  
Filtration Enrichment

Detection methods for Vibrio cholerae and Vibrio parahaemolyticus which included the culture based approach with polymerase chain reaction (PCR) confirmation, PCR detection without enrichment and PCR with a pre-enrichment were developed and their performance evaluated. PCR assays targeted the SodB (V. cholerae species), Flae (V. parahaemolyticus species), 16S rRNA (Vibrio and Enterobacteriacea species) genes (Multiplex 1) and V. cholerae O1 and V. cholerae O139 rfb genes, ctxA (cholera toxin) gene and 16S rRNA gene (Multiplex 2). These methods were used to determine the occurrence of selected Vibrios in source water as well as in household container-stored water. The combination of filtration, enrichment and PCR method provided a sensitive and specific method for the detection of selected Vibrios in water samples. The PCR with a pre-enrichment method detected as few as 4–10 cfu/100 mL of selected Vibrios and PCR detection without the enrichment method detected as few as 40–100 cfu/100 mL of selected Vibrios. The inclusion of an enrichment period allows detection of culturable bacteria. As an application of the developed methods, V. cholerae and V. parahaemolyticus were detected in the source water used by the population and in the water-storage containers. The results indicate that Vibrio species in the containers could have originated from the source water and survive in biofilms inside the containers.

COCHLIOBOLUS SATIVUS: IV. DRUG-RESISTANT, COLOR, AND NUTRITIONALLY EXACTING MUTANTS

1961 ◽  
Vol 39 (7) ◽  
pp. 1695-1704 ◽  
Author(s):  
R. D. Tinline
Keyword(s):  
Ultraviolet Radiation ◽  
Spontaneous Mutation ◽  
Resistant Mutant ◽  
Cochliobolus Sativus ◽  
Nutritional Deficiencies ◽  
Drug Resistant ◽  
Wild Type ◽  
Wheat Seedlings ◽  
Isolation Technique ◽  
Hyphal Tip

Auxotrophic mutants of Cochliobolus sativus were obtained from survivors of ultraviolet radiation by a modified total-isolation technique. Five or six hyphal tip isolations made from each survivor were tested for nutritional deficiencies. Although 0.48% of the survivors yielded auxotrophs, only about one-third of the hyphal tip isolations from these survivors were auxotrophic. Apparently, mutation in a multinucleate propagule resulted in a heterokaryotic culture and only some of the isolations from a culture were homokaryotic for the mutation. Some of the mutants were morphologically distinct from their parent and one, a methionineless strain, had white spores. Results indicated that recurrent requirements for growth occurred at different mutational sites.A strain resistant to the antibiotic anisomycin appeared as a spontaneous mutation. This strain grew at 1500 and its spores germinated at 1750 p.p.m.; wild-type isolates grew only at 75 and their spores germinated at 100 p.p.m. of the drug. The resistant mutant was pathogenic to wheat seedlings.

Influence of some carbon sources on growth of Cochliobolus sativus

1972 ◽  
Vol 50 (3) ◽  
pp. 683-685
Author(s):  
R. V. Clark
Keyword(s):  
Radial Growth ◽  
Mycelial Growth ◽  
Growth Response ◽  
Carbon Sources ◽  
Cochliobolus Sativus ◽  
Good Growth ◽  
Liquid Media ◽  
Differential Growth ◽  
Agar Media

Four isolates of C. sativus were able to use a number of carbon sources to varying degrees with little evidence of a differential growth response by the isolates. With most carbon sources the response was different when growth on liquid media was compared with that on agar media. Dextrin and L-sorbose were exceptions as dextrin supported good growth with both types and L-sorbose poor with both. Lactose supported the best mycelial growth on liquid media and dextrin the best radial growth and sporulation on agar media when compared with sucrose.

scholarly journals Reassessment of Vegetative Compatibility of Sclerotinia homoeocarpa Using Nitrate-Nonutilizing Mutants

2008 ◽  
Vol 98 (1) ◽  
pp. 108-114 ◽  
Author(s):  
Y.-K. Jo ◽  
S. W. Chang ◽  
J. Rees ◽  
G. Jung
Keyword(s):  
Minimal Medium ◽  
The United States ◽  
Vegetative Compatibility ◽  
Complete Medium ◽  
Sclerotinia Homoeocarpa ◽  
Hyphal Fusion ◽  
Vegetative Compatibility Groups ◽  
Nit Mutants ◽  
Mutant Phenotypes ◽  
First Time

Nitrate-nonutilizing (nit) mutants were recovered for the first time from 21 isolates of Sclerotinia homoeocarpa collected in the United States. Mutants were selected from shredded mycelium of each isolate when cultured on water agar medium amended with 4% (wt/vol) potassium chlorate. The mutants could be classified into three phenotypes: nit1, nit3, and NitM, based on their growth on minimal medium (Czapek solution agar) supplemented with NaNO2 or hypoxanthine. Complementary heterokaryons were observed in pairings between different phenotypes of nit mutants derived from compatible isolates, but not in self-fusions or pairings between incompatible isolates. The vigor of prototrophic growth varied with isolates and mutant phenotypes. Strong and continuous heterokaryons, as well as weak and spontaneous ones, formed depending on pairings of nit mutants. Stable heterokaryons between compatible isolates, but apoptotic reactions between incompatible isolates, were observed immediately after hyphal fusion under the epifluorescence microscope. The 21 isolates used in this study, which were previously assigned into 11 different vegetative compatibility groups (VCGs) based on the formation of a barrage zone at the contact site of paired isolates on complete medium (potato dextrose agar), were regrouped into five VCGs based on heterokaryon formation between nit mutants on minimal medium.

scholarly journals Genetic manipulation of Saccharomyces cerevisiae by use of the LYS2 gene.

1986 ◽  
Vol 6 (8) ◽  
pp. 2828-2838 ◽  
Author(s):  
D A Barnes ◽  
J Thorner
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Structural Gene ◽  
Minimal Medium ◽  
Genetic Manipulation ◽  
Gene Replacement ◽  
Complete Medium ◽  
Dna Library ◽  
Genomic Dna Library ◽  
Chromosome Ii ◽  
In Cells

The structural gene for alpha-aminoadipate reductase (LYS2) was isolated from a Saccharomyces cerevisiae genomic DNA library by complementation of a lys2 mutant. Both genetic and biochemical criteria confirmed that the DNA obtained corresponds to the LYS2 locus on chromosome II. Subcloning and deletion analysis showed that a functional LYS2 gene is contained within a 4.6-kilobase (kb) EcoRI-HindIII fragment of the original insert, and the slightly larger EcoRI-ClaI segment (4.8 kb) was used to construct a series of cloning vehicles, including integrating, episomal, replicative, and centromeric vectors. The cloned DNA was also used to generate a genomic deletion that lacks all LYS2 coding sequences on chromosome II. The level of the LYS2 transcript (4.2 kb) was 10-fold higher in cells grown on minimal medium than in cells grown on complete medium and was not repressed by the presence of lysine alone. Gene disruption, gene replacement, and promoter analysis of the major alpha-factor structural gene (MF alpha 1) were performed to illustrate the utility of the LYS2 gene for the genetic manipulation of yeasts. Because all fungi synthesize lysine via the alpha-aminoadipate pathway, the techniques developed here for using the S. cerevisiae LYS2 gene should be directly applicable to other fungal systems.

scholarly journals Filtration enrichment method for isolation of auxotrophic mutants of Trichoderma harzianum rifai

1999 ◽  
Vol 30 (1) ◽  
pp. 43-46
Author(s):  
Ana Maria R. Cassiolato ◽  
Itamar Soares de Melo
Keyword(s):  
Growth Rate ◽  
Trichoderma Harzianum ◽  
Genetic Research ◽  
Wild Type ◽  
Enrichment Method ◽  
Isolation Technique ◽  
Auxotrophic Mutants ◽  
Enrichment Technique ◽  
Filtration Enrichment ◽  
Similar Growth

The isolation of genetic markers, like drug resistance and auxotrophy, is a laborious but important step in genetic research. The isolation of auxotrophic mutants of Trichoderma harzianum using the filtration enrichment technique was more effective than using the total isolation technique. Most of 12 auxotrophic mutants exhibited similar growth rate and higher sporulation when compared with the wild type, but only two mutants (TWS-410 and TW5-523) could grow in 500µg/L of benomyl.

scholarly journals CHARACTERIZATION OF THE HETEROKARYOTIC AND VEGETATIVE DIPLOID PHASES OF MAGNAPORTHE GRISEA

Genetics ◽  
1986 ◽  
Vol 114 (4) ◽  
pp. 1111-1129
Author(s):  
Mark S Crawford ◽  
Forrest G Chumley ◽  
Carolyn G Weaver ◽  
Barbara Valent
Keyword(s):  
Minimal Medium ◽  
Magnaporthe Grisea ◽  
Fast Growing ◽  
Dominance Testing ◽  
Wide Range ◽  
Nutritional Characteristics ◽  
Single Nucleus ◽  
Tip Cells ◽  
Hyphal Tip

ABSTRACT The heterokaryotic and vegetative diploid phases of Magnaporthe grisea, a fungal pathogen of grasses, have been characterized. Prototrophic heterokaryons form when complementary auxotrophs are paired on minimal medium. Hyphal tip cells and conidia (vegetative spores) taken from these heterokaryons are auxotrophs with phenotypes identical to one or the other of the parents. M. grisea heterokaryons thus resemble those of other fungi that have completely septate hyphae with a single nucleus per cell. Heterokaryons have been utilized for complementation and dominance testing of mutations that affect nutritional characteristics of the fungus. Heterokaryons growing on minimal medium spontaneously give rise to fast-growing sectors that have the genetic properties expected of unstable heterozygous diploids. In fast-growing sectors, most hyphal tip cells are unstable prototrophs. The conidia collected from fast-growing sectors include stable and unstable prototrophs, as well as auxotrophs that exhibit a wide range of phenotypes, including many recombinant classes. Genetic linkage in meiosis has been detected between two auxotrophic mutations that recombine in vegetatively growing unstable diploids. The appearance of recombinants suggests that homologous recombination occurs during vegetative growth of M. grisea. No interstrain barriers to heterokaryosis and diploid formation have been detected. The mating type of the strains that are paired does not influence the formation of heterokaryons or diploids.

Multilayer and multichannel membrane filtration for separation and preconcentration of trace analytes and its application in spectral analysis

2016 ◽  
Vol 8 (1) ◽  
pp. 129-135 ◽  
Author(s):  
Wei Li ◽  
Haiting Wang ◽  
Wei Jiang ◽  
Lei Wang ◽  
Ruoqiu Zhang ◽  
...  
Keyword(s):  
Spectral Analysis ◽  
Membrane Filtration ◽  
Enrichment Method ◽  
Filtration Enrichment ◽  
Separation And Preconcentration ◽  
Mixture Samples

A multilayer and multichannel membrane filtration-enrichment method was developed to simultaneously separate and enrich trace analytes in mixture samples.

scholarly journals Heterokaryon formation in Coprinus lagopus

1960 ◽  
Vol 1 (1) ◽  
pp. 114-128 ◽  
Author(s):  
K. M. Swiezynski ◽  
P. R. Day
Keyword(s):  
Mating Type ◽  
Growth Rates ◽  
Minimal Medium ◽  
The Other ◽  
Complete Medium ◽  
Wild Type ◽  
Heterozygous Locus ◽  
Heterokaryon Formation ◽  
The Common

1. The four possible kinds of heterokaryon of Coprinus lagopus with no, one or both mating-type factors in common (dikaryon, common A, common B and common AB) were produced. Analysis of hyphal tips of common A and common AB heterokaryons has shown that both nuclei may be present in the same hypha.2. All four heterokaryons are prototrophic when synthesized from two auxotrophic components with different requirements.3. When synthesized in this way compatible heterokaryons were stable in all tests, but the other heterokaryons showed different degrees of stability. Common B heterokaryons were the most stable and rarely gave rise to monokaryotic mycelia. Dissociation of the common A and the common AB heterokaryon into either component took place much more easily.4. Comparisons of the growth-rates of wild-type heterokaryons on complete medium show that common A heterokaryons are less vigorous, and dikaryons more vigorous than their monokaryon components. On minimal medium both compatible and common A heterokaryons are less vigorous than their wild-type monokaryon components. The possible reasons for this are discussed.5. Fruit-bodies have been obtained from both common A and common B heterokaryons. Both types showed normal segregation at the heterozygous locus (B or A), but showed in addition the segregation of new reactions at the ‘homozygous’ locus.

Genetic manipulation of Saccharomyces cerevisiae by use of the LYS2 gene

1986 ◽  
Vol 6 (8) ◽  
pp. 2828-2838
Author(s):  
D A Barnes ◽  
J Thorner
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Structural Gene ◽  
Minimal Medium ◽  
Genetic Manipulation ◽  
Gene Replacement ◽  
Complete Medium ◽  
Dna Library ◽  
Genomic Dna Library ◽  
Chromosome Ii ◽  
In Cells

The structural gene for alpha-aminoadipate reductase (LYS2) was isolated from a Saccharomyces cerevisiae genomic DNA library by complementation of a lys2 mutant. Both genetic and biochemical criteria confirmed that the DNA obtained corresponds to the LYS2 locus on chromosome II. Subcloning and deletion analysis showed that a functional LYS2 gene is contained within a 4.6-kilobase (kb) EcoRI-HindIII fragment of the original insert, and the slightly larger EcoRI-ClaI segment (4.8 kb) was used to construct a series of cloning vehicles, including integrating, episomal, replicative, and centromeric vectors. The cloned DNA was also used to generate a genomic deletion that lacks all LYS2 coding sequences on chromosome II. The level of the LYS2 transcript (4.2 kb) was 10-fold higher in cells grown on minimal medium than in cells grown on complete medium and was not repressed by the presence of lysine alone. Gene disruption, gene replacement, and promoter analysis of the major alpha-factor structural gene (MF alpha 1) were performed to illustrate the utility of the LYS2 gene for the genetic manipulation of yeasts. Because all fungi synthesize lysine via the alpha-aminoadipate pathway, the techniques developed here for using the S. cerevisiae LYS2 gene should be directly applicable to other fungal systems.

Sign in / Sign up

Export Citation Format

Share Document