COCHLIOBOLUS SATIVUS: VII. NUTRITIONAL CONTROL OF THE PATHOGENICITY OF SOME AUXOTROPHS TO WHEAT SEEDLINGS

1963 ◽  
Vol 41 (4) ◽  
pp. 489-497 ◽  
Author(s):  
R. D. Tinline
Keyword(s):  
Cochliobolus Sativus ◽  
Nutritional Requirements ◽  
Wheat Seedlings ◽  
Auxotrophic Mutants ◽  
Growth Requirements ◽  
Common Parent

The pathogenicity of some strains of Cochliobolus sativus to wheat seedlings was determined. The strains comprised prototrophic and auxotrophic mutants from a common parent, heterokaryons synthesized from auxotrophs, diploids obtained from heterokaryons, and recombinants selected from a diploid.Prototrophic mutants and auxotrophs requiring thiamine, arginine, and pyridoxine were as pathogenic as the parent. Methionineless and lysineless mutants were non-pathogenic. Evidence that the nutritional requirements of the latter mutants directly controlled their pathogenicity was: (1) two methionineless and two lysineless auxotrophs were uniformly non-pathogenic; (2) heterokaryons synthesized from methionineless and lysineless strains and from two methionineless strains were pathogenic; (3) diploids heterozygous for the requirements were pathogenic; (4) prototrophic recombinants from a diploid were pathogenic but auxotrophic ones were non-pathogenic; (5) a prototrophic mutant of a lysineless auxotroph was pathogenic; and (6) the pathogenicity of the auxotrophs was temporarily restored when the appropriate growth requirements were provided as external supplements to the host. The results are discussed.

scholarly journals Growth requirements of thermophilic aerobic microorganisms in mixed cultures for the treatment of strong wastes

1999 ◽  
Vol 40 (1) ◽  
pp. 53-60 ◽  
Author(s):  
G. Sürücü
Keyword(s):  
Mixed Culture ◽  
Maximum Growth ◽  
Effect Of Temperature ◽  
Nutritional Requirements ◽  
Nitrogen And Phosphorus ◽  
Thermophilic Microorganisms ◽  
Naturally Occurring ◽  
Growth Requirements ◽  
Phosphorus Sources ◽  
Pure Cultures

The nutritional and temperature requirements of a naturally occurring mixed culture of thermophilic microorganisms were studied. Investigations concerning the effect of temperature on the growth characteristics of the mixed culture showed that the rate of growth was highest between 55 and 58°C. Furthermore, it was found that the minimal nutritional requirements for maximum growth of these microorganisms included methionine, magnesium, calcium, and the necessary carbon, nitrogen and phosphorus sources. It was shown that a mixed culture was nutritionally less fastidious than the pure cultures of individual organisms isolated from the mixed culture; this observation illustrated the possibility of symbiotic growth of thermophilic microorganisms insofar as meeting their individual nutritional requirements.

GROWTH REQUIREMENTS OF 94 STRAINS OF THERMOPHILIC BACILL

1960 ◽  
Vol 6 (5) ◽  
pp. 557-563 ◽  
Author(s):  
H. Baker ◽  
O. Frank ◽  
I. Pasher ◽  
B. Black ◽  
S. H. Hutner ◽  
...  
Keyword(s):  
Bacillus Stearothermophilus ◽  
Nutritional Requirements ◽  
Vitamin B ◽  
Methyl Donor ◽  
Growth Requirements ◽  
Effects Of Temperature

The minimal nutritional requirements of 94 thermophilic strains of the species Bacillus stearothermophilus and B. coagulans, grown at 55 °C, were determined. Most strains had an absolute methionine requirement. Some strains synthesized methionine by means of a methyl donor (choline, betaine), a methyl acceptor (homocystine), and a methyl activator (vitamin B12). The effects of temperature as inducing variations in nutritional requirements are briefly discussed.

Comparative pathogenicity of auxotrophic mutants of Candida albicans

1984 ◽  
Vol 30 (1) ◽  
pp. 31-35 ◽  
Author(s):  
Marcia Manning ◽  
Christina B. Snoddy ◽  
Robert. A. Fromtling
Keyword(s):  
Candida Albicans ◽  
Parent Strain ◽  
Antifungal Drugs ◽  
Mouse Serum ◽  
Temperature Sensitive ◽  
Auxotrophic Mutants ◽  
Growth Requirements ◽  
Induced Mutant

An induced mutant of Candida albicans with greatly decreased virulence for mice is described. The mutant was one of five auxotrophic mutants obtained by ultraviolet irradiation of a clinical isolate (strain MY 1044). The five mutants included two methionine auxotrophs, one methionine–cysteine auxotroph, one temperature-sensitive serine auxotroph, and one auxotroph with unknown growth requirements. Each of the mutants produced normal mycelium and had a normal profile of susceptibility to four antifungal drugs. The virulence of each mutant was compared with the parent strain by LD50 determination in mice. Four of the five auxotrophs exhibited LD50's that were not significantly different from the parent strain (mean LD50 = 7.5 × 105 cells). However, the temperature-sensitive serine auxotroph was significantly less virulent than the parent strain (LD50 > 107 cells), even though it grew well in vivo and in mouse serum at 37 °C in vitro. Use of this mutant in conjunction with its "isogenic" parent should help to elucidate true virulence factors in C. albicans.

Nutritional requirements ofCytophaga johnsonae and some of its auxotrophic mutants

1981 ◽  
Vol 5 (4) ◽  
pp. 235-240 ◽  
Author(s):  
Li-Yen Edward Chang ◽  
Jack L. Pate
Keyword(s):  
Nutritional Requirements ◽  
Auxotrophic Mutants

Comparative stability and growth requirements of S. aureus and faecal indicator bacteria in seawater

2006 ◽  
Vol 54 (3) ◽  
pp. 169-175 ◽  
Author(s):  
R.S. Fujioka ◽  
T.M. Unutoa
Keyword(s):  
Environmental Conditions ◽  
Water Samples ◽  
High Salinity ◽  
Indicator Bacteria ◽  
Nutritional Requirements ◽  
Recreational Waters ◽  
E Coli ◽  
Growth Requirements ◽  
Comparative Stability ◽  
Bactericidal Agent

The fate (stability, multiplication) of S. aureus, E. coli and E. faecalis was determined in three classes of recreational waters (seawater, estuarine, stream) supplemented with nutrients in the form of sewage and peptone. In the absence of sunlight (24±2 °C), all bacteria in all water samples did not multiply and were slowly (days) inactivated. When 50% sewage was added to all water samples, E. coli and E. faecalis multiplied but S. aureus did not. When peptone (0.05%, 0.5%) was the added nutrient, the three bacteria multiplied. In the presence of sunlight (15–27 °C), S. aureus was inactivated rapidly (hours) in all water samples. These results show that when their nutritional requirements are met, S. aureus, E. coli and E. faecalis can multiply in the high salinity conditions of seawater. However, under environmental conditions, sunlight is an effective natural bactericidal agent.

GENETICS OF PHYTOPATHOGENIC FUNGI: VIRULENCE OF COLOR AND NUTRITIONALLY DEFICIENT MUTANTS OF PENICILLIUM ITALICUM AND PENICILLIUM DIGITATUM

1964 ◽  
Vol 42 (4) ◽  
pp. 429-436 ◽  
Author(s):  
L. Beraha ◽  
E. D. Garber ◽  
Ø. Strømnaes
Keyword(s):  
Ultraviolet Light ◽  
Parental Strain ◽  
Citrus Fruit ◽  
Phytopathogenic Fungi ◽  
Fruit Rot ◽  
Nutritional Requirements ◽  
Penicillium Italicum ◽  
Auxotrophic Mutants ◽  
Specific Alteration ◽  
Weakly Virulent

Prototrophic color and auxotrophic mutants of Penicillium italicum and P. digitatum, causal agents of citrus fruit rot, were obtained by irradiating conidia with ultraviolet light. Avirulent mutants caused a necrosis but not an obvious rot at the site of inoculation in orange rind. Avirulence was not necessarily associated with a specific alteration in the color of sporulating colonies or with the tested nutritional requirements. Supplementing necrotic lesions with the compounds required by the avirulent auxotrophic mutants enhanced growth but did not cause an obvious rot. Although heterocaryons of P. italicum involving avirulent auxotrophic strains were weakly virulent, the corresponding diploid strains were as virulent as the haploid prototrophic parental strain. Prototrophic segregants from the diploid strains were virulent. Avirulence was not related to the inability of the avirulent mutants to grow at the site of inoculation. It is probable that more than one locus may be responsible for the loss of virulence.

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.

MALIC ENZYME INDUCTION BY LACTIC ACID BACTERIA: I. A METHOD FOR THE STUDY OF NUTRITIONAL INTERACTIONS

1961 ◽  
Vol 7 (2) ◽  
pp. 153-161 ◽  
Author(s):  
S. J. Deal ◽  
Herman C. Lichstein
Keyword(s):  
Lactic Acid ◽  
Amino Acid ◽  
Lactic Acid Bacteria ◽  
Enzyme Induction ◽  
Malic Enzyme ◽  
Enzyme Synthesis ◽  
Nutritional Requirements ◽  
Growth Requirements ◽  
Lactobacillus Arabinosus

The nutritional requirements for the induction of malic enzyme by washed cellular suspensions of Lactobacillus arabinosus 17-5 have been found to be quite similar to the growth requirements for this organism. This similarity permits the use of the measure of rate and extent of malic enzyme synthesis as a tool for studying amino acid interactions and vitamin function.

COCHLIOBOLUS SATIVUS: III. EFFECT OF ULTRAVIOLET RADIATION

1960 ◽  
Vol 38 (3) ◽  
pp. 275-282 ◽  
Author(s):  
R. D. Tinline ◽  
J. F. Stauffer ◽  
J. G. Dickson
Keyword(s):  
Ultraviolet Radiation ◽  
Ultraviolet Light ◽  
Aerial Mycelium ◽  
Mutagenic Effect ◽  
Cochliobolus Sativus ◽  
Highly Pathogenic ◽  
Wheat Seedlings ◽  
Rate Of Growth ◽  
High Doses ◽  
Sporulation Rate

The lethal and mutagenic effect of ultraviolet light on two isolates of Cochliobolus sativus was studied. Conidia of a dark-spored strain were considerably more resistant to high doses of radiation than those of a white-spored strain. Ultraviolet radiation increased the frequency of mutation in the fungus. Mutants were recovered that differed from their parents in degree of sporulation, rate of growth, pigmentation, amount of aerial mycelium, topography and consistency of colony, and pathogenicity to wheat seedlings. Tetrads from crosses between weakly and highly pathogenic strains indicated that pathogenicity was not a clearly segregating character.

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