THE ISOLATION AND IDENTIFICATION OF POLYPLOID STRAINS OF USTILAGO VIOLACEA

1972 ◽  
Vol 14 (4) ◽  
pp. 925-932 ◽  
Author(s):  
Alan W. Day
Keyword(s):  
Growth Rate ◽  
Stationary Phase ◽  
Cell Volume ◽  
Mating Type ◽  
Dominant Allele ◽  
Isolation And Identification ◽  
Volume Stability ◽  
Type Allele ◽  
Rate Decrease ◽  
Ustilago Violacea

A method for the synthesis of polyploid strains of Ustilago violacea and the criteria for their identification are described. Cell length increases directly in proportion to the ploidy and thus the volume of the cell increases very rapidly at higher ploidies. The volume of the nucleus also increases but remains at a constant 3-4% of the cell volume. Stability and growth rate decrease with increasing ploidy. The a2 mating-type allele acts as a simple dominant allele in log phase cells, but there is no dominance in stationary phase cells.

scholarly journals A modifier gene involved in the expression of the dominant mating type allele in Paramecium caudatum

1976 ◽  
Vol 27 (2) ◽  
pp. 135-141 ◽  
Author(s):  
Koichi Hiwatashi ◽  
Koji Myohara
Keyword(s):  
Mating Type ◽  
Modifier Gene ◽  
Recessive Allele ◽  
Dominant Allele ◽  
Paramecium Caudatum ◽  
Mutant Clone ◽  
Wild Type ◽  
Type Allele ◽  
Type V

SUMMARYMating type in Paramecium caudatum, syngen 3 is determined by a pair of alleles with simple dominance; the recessive allele restricts homozygotes to mating type V and the dominant allele permits expression of mating type VI. Clones of mating type V never show natural selfing, but most clones of mating type VI self naturally. A mutant clone of mating type VI which never selfed over a period of more than 3 years was obtained by treatment with N-methyl-N′-nitro-N-nitrosoguanidine. When this mutant clone was crossed to a wild-type stock of mating type V, all F1 clones of mating type VI gave rise to selfers. From selfing of these F1 of mating type VI, clones of F2 were obtained. Nearly 3:1 segregation of selfer to non-selfer clones was observed among the F2 clones of mating type VI. The results were consistent with the interpretation that a dominant modifier gene, Su(+mtV), controls the instability in the expression of mating type VI.

scholarly journals The production and behaviour of diploids of Coprinus lagopus

1965 ◽  
Vol 6 (2) ◽  
pp. 190-208 ◽  
Author(s):  
Lorna A. Casselton
Keyword(s):  
Growth Rate ◽  
Mating Type ◽  
Fruiting Body ◽  
Selective Medium ◽  
Diploid Nucleus ◽  
Common Allele ◽  
Fruiting Bodies ◽  
Haploid Nucleus ◽  
Type Allele ◽  
The Common

Diploid strains of Coprinus lagopus have been synthesized from common A heterokaryons either as oidial colonies or sectors. The criteria of growth rate and colony morphology on selective medium were used to distinguish between diploid and heterokaryon colonies. The average oidial size and hyphal width of diploid strains was significantly greater than that of the haploid parental strains.Diploid monokaryons were very stable and only rarely produced haploid segregants. However, aneuploid intermediates in haploidization have been identified and these segregated further to give haploid monokaryons with recombinant genomes.Dikaryons formed from diploid and haploid strains produced fruiting bodies. Meiosis and basidiospore production were irregular owing to the formation of triploid or partially triploid fusion nuclei in the basidia. In contrast to their stability in monokaryons, diploid nuclei tended to be unstable when combined in a dikaryon with a haploid nucleus, and often underwent partial haploidization before fruiting. Segregation of genes in the basidiospore progeny reflected whether haploidization had occurred before or after the formation of the fruiting body. If the haploid nucleus had a B mating-type allele common to the diploid nucleus, haploidization effected loss of the common allele.

scholarly journals Disseminated cryptococcosis in an AIDS patient caused by a canavanine-resistant strain of Cryptococcus neoformans var. grubii

2003 ◽  
Vol 52 (3) ◽  
pp. 271-275 ◽  
Author(s):  
Z.U. Khan ◽  
A.A. Al-Anezi ◽  
R. Chandy ◽  
J. Xu
Keyword(s):  
Cryptococcus Neoformans ◽  
Mating Type ◽  
Resistant Strain ◽  
Bromothymol Blue ◽  
Lymph Node Biopsy ◽  
Yeast Cells ◽  
Isolation And Identification ◽  
Serotype A ◽  
Type Allele ◽  
Clear Cut

A case of disseminated cryptococcosis caused by Cryptococcus neoformans var. grubii is presented in a male diabetic who had AIDS. The diagnosis was based upon the isolation and identification of the aetiological agent from a lymph-node biopsy, cerebrospinal fluid and sputum. The isolate formed spherical, encapsulated yeast cells, produced cherry-brown colonies on niger-seed agar, grew on canavanine-glycine-bromothymol blue (CGB) medium, changing its colour from greenish yellow to blue, and hydrolysed urea weakly in the presence of 100 μM EDTA. The strain was unable to assimilate d-proline and, serologically, it was untypable. The identity of the isolate as C. neoformans var. grubii, serotype A, possessing a mating-type allele Aα, was confirmed by crossing with standard laboratory test strains and by performing PCR with the mating-type α allele-specific primer of the STE12 gene and with serotype (A and D)- and mating type (a and α)-specific primers of the STE20 gene. To the best of our knowledge, this is the first report of disseminated cryptococcosis in an AIDS patient caused by a canavanine-resistant strain of C. neoformans var. grubii, serotype A, possessing mating type allele Aα; the strain is probably a hybrid. The report suggests that, in the absence of a clear-cut serotyping result, a positive CGB reaction alone is not sufficient for intervarietal discrimination and additional confirmatory evidence is required.

scholarly journals MUTATIONS INCREASING ASEXUAL PLASMODIUM FORMATION IN PHYSARUM POLYCEPHALUM

Genetics ◽  
1977 ◽  
Vol 87 (3) ◽  
pp. 401-420
Author(s):  
Paul N Adler ◽  
Charles E Holt
Keyword(s):  
Life Cycle ◽  
Mating Type ◽  
Physarum Polycephalum ◽  
The Other ◽  
Type Allele ◽  
Cold Sensitive ◽  
The One

ABSTRACT Rare plasmodia formed in clones of heterothallic amoebae were analyzed in a search for mutations affecting plasmodium formation. The results show that the proportion of mutants varies with both temperature (18°, 26° or 30°) and mating-type allele (mt1, mt2, mt3, mt4). At one extreme, only one of 33 plasmoida formed by mt2 amoebae at 18° is mutant. At the other extreme, three of three plasmodia formed by mt1 amoebae at 30° are mutant. The mutant plasmodia fall into two groups, the GAD (greater asexual differentiation) mutants and the ALC (amoebaless life cycle) mutants. The spores of GAD mutants give rise to amoebae that differentiate into plasmodia asexually at much higher frequencies than normal heterothallic amoebae. Seven of eight gad mutations analyzed genetically are linked to mt and one (gad-12) is not. The gad-12 mutation is expressed in strains with different alleles of mt. The frequency of asexual plasmodium formation is heat sensitive in some (e.g., mt3 gad-11), heat-insensitive in two (mt2 gad-8 and mt2 gad-9) and cold-sensitive in one (mt1 gad-12) of twelve GAD mutants analyzed phenotypically. The spores of ALC mutants give rise to plasmodia directly, thereby circumventing the amoebal phase of the life cycle. Spores from five of the seven ALC mutants give rise to occasional amoebae, as well as plasmodia. The amoebae from one of the mutants carry a mutation (alc-1) that is unlinked to mt and is responsible for the ALC phenotype in this mutant. Like gad-12, alc-1 is expressed with different mt alleles. Preliminary observations with amoebae from the other four ALC mutants suggest that two are similar to the one containing alc-1; one gives rise to revertant amoebae, and one gives rise to amoebae carrying an alc mutation and a suppressor of the mutation.

Growth Kinetics of Salmonella Isolates in a Laboratory Medium as Affected by Isolate and Holding Temperature†

1998 ◽  
Vol 61 (8) ◽  
pp. 964-968 ◽  
Author(s):  
THOMAS P. OSCAR
Keyword(s):  
Growth Rate ◽  
Stationary Phase ◽  
Growth Kinetics ◽  
Brain Heart Infusion ◽  
Lag Time ◽  
Culture Collection ◽  
Subsequent Growth ◽  
Laboratory Medium ◽  
Different Temperatures ◽  
Holding Temperature

Salmonella isolates were surveyed for their growth kinetics in a laboratory medium for the purpose of identifying isolates suitable for modeling experiments. In addition, the effect of holding stationary phase Salmonella cultures at different temperatures on their subsequent growth kinetics was evaluated for the purpose of developing a protocol to prevent the need for midnight sampling in modeling experiments. In Experiment 1, 16 isolates of Salmonella, 2 from the American Type Culture Collection (ATCC) and 14 from broiler operations, were surveyed for their growth kinetics in brain heart infusion (BHI) broth at 40°C. Lag time (P = 0.005) and growth rate (P = 0.022) were affected by identity of the isolate. Lag time ranged from 0.73 to 1.38 h, whereas growth rate ranged from 0.78 to 0.94 log10 CFU/ml/h. Overall, isolate S1 (Salmonella infantis from ATCC) was the fastest growing. In Experiment 2, 4 isolates of Salmonella, 1 from ATCC and 3 from broiler operations, were used to determine whether holding temperature influences subsequent growth kinetics. Salmonella isolates were grown to stationary phase at 37°C in BHI and then held for 24 h at 5, 22, or 37°C before dilution and reinitiation of growth in BHI at 37°C. Holding temperature did not alter or interact with identity of the isolate to alter subsequent growth kinetics. From the latter finding, a protocol was devised in which a dual-flask system is used to prevent the need for midnight sampling in modeling experiments. Similar to the results obtained in Experiment 1, identity of the isolate had only minor effects on growth kinetics in Experiment 2 indicating that all isolates examined were suitable for modeling experiments.

Properties of conjugation hormones (erogens) from the basidiomycete Tremella mesenteria

1974 ◽  
Vol 52 (3) ◽  
pp. 521-524 ◽  
Author(s):  
Ian D. Reid
Keyword(s):  
Mating Type ◽  
Active Material ◽  
The Other ◽  
Active Components ◽  
Small Peptides ◽  
Isolation And Identification ◽  
Polar Solvents ◽  
Anion Exchange Resins ◽  
Polystyrene Resin ◽  
Exchange Resins

Hormones produced by haploid cells of one mating type of T. mesenterica and inducing conjugation tubes in the other mating type have been studied in preparation for isolation and identification. The active material can be extracted from aqueous solution with n-butanol, but not with less polar solvents, and is adsorbed on cation and anion exchange resins, charcoal, and neutral polystyrene resin. The molecular weight is probably less than 1000. Three active components can be separated by silica gel column chromatography with a gradient of water in ethanol, or by paper chromatography. The conjugation hormones may be non-polar amino acids or small peptides.

POOR FRUITERS AND BARRAGE MUTANTS IN GELASINOSPORA

1956 ◽  
Vol 34 (2) ◽  
pp. 231-240 ◽  
Author(s):  
E. Silver Dowding ◽  
A. Bakerspigel
Keyword(s):  
Growth Rate ◽  
Mating Type ◽  
Opposite Mating Type ◽  
Nutritional Factors ◽  
Wild Strains ◽  
Hyphal Tip

Anomalous sterility and slow fruiting occur among the following types of cultures: (1) mated homokaryotic mycelia grown from dwarf ascospores; (2) heterokaryotic mycelia grown from normal-sized ascospores; (3) hyphal-tip cultures from heterokaryotic mycelia. Such behavior may be caused by a mutant nucleus whose nutritional factors do not complement those in the nuclei of opposite mating type. Among the sterile and slow-fruiting strains were found 'barrage' mutants. They differ in texture and growth rate from wild strains. When grown in pairs, their hyphac, as they approach each other, exhibit aversion or barrage. Progeny of mated barrage strains are likewise barrage strains.

scholarly journals Regulation of fitness in yeast overexpressing glycolytic enzymes: parameters of growth and viability

1992 ◽  
Vol 59 (1) ◽  
pp. 35-48 ◽  
Author(s):  
R. F. Rosenzweig
Keyword(s):  
Growth Rate ◽  
Stationary Phase ◽  
Specific Activity ◽  
Current Model ◽  
Carbon Sources ◽  
Fold Increase ◽  
Culture Cell ◽  
Phase Density ◽  
Enzyme Specific Activity ◽  
High Copy Plasmid

SummaryCurrent models predict that large increases over wild-type in the activity of one enzyme will not alter an organism's fitness. This prediction is tested in Saccharomyces cerevisiae through the use of a high copy plasmid that bears one of the following: hexokinase B (HEXB), phosphoglucose isomerase (PGI), phosphofructokinase (PFKAandPFKB), or pyruvate kinase (PYK). Transformants containing these plasmids demonstrate a four to ten-fold increase in enzyme specific activity over either the parent strain or transformants containing the plasmid alone. Haploid and diploid transformants derived from independent backgrounds were grown on both fermentable and non-fermentable carbon sources and evaluated for several components of fitness. These include growth rate under non-limiting conditions, maximum stationary phase density, and viability in extended batch culture. Cell viability is not affected by overproduction of these enzymes. Growth rate and stationary phase density do not differ significantly among strains that overexpressHEXB, PGIor contain the vector alone.PFKA, Btransformants show reduced growth rate on glucose in one background only. For these loci the current model is confirmed. By contrast, when grown on glucose, yeast overexpressingPYKdemonstrate reduced growth rate and increased stationary phase density in both backgrounds. These effects are abolished in cells containing plasmids with a Tn5 disrupted copy of thePYKgene. Our results are consistent with reports that the PYK locus may exert control over the yeast cell cycle and suggest that it will be challenging to model relations between fitness and activity for multifunctional proteins.

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