scholarly journals Changes in genetic constitution and sterol composition during growth of nystatin-resistant heterokaryons ofNeurospora crassa

1983 ◽  
Vol 42 (1) ◽  
pp. 91-103 ◽  
Author(s):  
Jill E. Ogden ◽  
Morris Grindle
Keyword(s):  
Growth Rates ◽  
Minimal Medium ◽  
Resistant Mutant ◽  
Sterol Composition ◽  
Sensitive Strain ◽  
Genetic Constitution ◽  
Polyene Antibiotic ◽  
Ofneurospora Crassa ◽  
Synthetic Media ◽  
Selection Of

SUMMARYHeterokaryons ofN. crassawere synthesized from homokaryotic strains differing in sterol composition and sensitivity to the polyene antibiotic nystatin. Mycelia of the nystatin-sensitive strainerg-1+contained ergosterol and episterol, and the nystatin-resistant mutanterg-1 contained fecosterol and lichesterol. Mycelia of heterokaryons with different proportions oferg-1+:erg-1 nuclei contained various proportions of the four sterols. Ergosterol was the principal sterol in heterokaryons with more than 5%erg-1+nuclei.Heterokaryons with various proportions oferg-1+:erg-1 nuclei were grown for several weeks along tubes of synthetic media. Growth rates were stable on minimal medium and nutritionally supplemented media but nuclear proportions often fluctuated. Growth rates fell sharply on nystatin-supplemented media and there were adaptive increases in proportions of mutanterg-1 nuclei which resulted in selection of nystatin-resistant homokaryotic mycelia.

scholarly journals An easy way of obtainingAspergillus nidulanshaploids in the parasexual cycle usingN-glycosyl polifungin

1975 ◽  
Vol 25 (3) ◽  
pp. 249-252 ◽  
Author(s):  
Jerzy Bal ◽  
Ewa Bartnik ◽  
Bożenna Goryluk ◽  
Norman J. Pieniążek
Keyword(s):  
Aspergillus Nidulans ◽  
Differential Effect ◽  
Minimal Medium ◽  
Considerable Improvement ◽  
Linkage Studies ◽  
Linkage Groups ◽  
Polyene Antibiotic ◽  
Parasexual Cycle ◽  
Growth Requirements ◽  
Selection Of

SUMMARYA considerable improvement in the selection of haploids inAspergillus nidulansis described. Haploidization is used to assign genes to linkage groups (chromosomes) in fungi. The differential effect of a polyene antibiotic,N-glycosyl-polifungin, in respect to haploids and diploids, was utilized. In minimal medium only diploids (constructed from a ‘Master Strain’ and the investigated strain), which are fully heterozygous and thus have no growth requirements, germinate and are killed by the antibiotic. However, auxotrophic haploids, either induced or spontaneously formed, survive. These can then be used for linkage studies.

scholarly journals Coriolis effects on the elliptical instability in cylindrical and spherical rotating containers

2007 ◽  
Vol 585 ◽  
pp. 323-342 ◽  
Author(s):  
M. LE BARS ◽  
S. LE DIZÈS ◽  
P. LE GAL
Keyword(s):  
Growth Rates ◽  
Close Agreement ◽  
Unstable Mode ◽  
Quantitative Agreement ◽  
Fixed Rate ◽  
Elliptical Instability ◽  
Normal Mode Theory ◽  
Set Up ◽  
First Time ◽  
Selection Of

The effects of the Coriolis force on the elliptical instability are studied experimentally in cylindrical and spherical rotating containers placed on a table rotating at a fixed rate $\tilde{\Omega}^G$. For a given set-up, changing the ratio ΩG of global rotation $\tilde{\Omega}^G$ to flow rotation $\tilde{\Omega}^F$ leads to the selection of various unstable modes due to the presence of resonance bands, in close agreement with the normal-mode theory. No instability occurs when ΩG varies between −3/2 and −1/2 typically. On decreasing ΩG toward −1/2, resonance bands are first discretized for ΩG<0 and progressively overlap for −1/2 ≪ ΩG < 0. Simultaneously, the growth rates and wavenumbers of the prevalent stationary unstable mode significantly increase, in quantitative agreement with the viscous short-wavelength analysis. New complex resonances have been observed for the first time for the sphere, in addition to the standard spin-over. We argue that these results have significant implications in geo- and astrophysical contexts.

scholarly journals Screening of local wild-type Xanthomonas spp. for xanthan biosynthesis using media with different carbon sources

2021 ◽  
Vol 26 (4) ◽  
pp. 2800-2807
Author(s):  
IDA ZAHOVIĆ ◽  
JELENA DODIĆ ◽  
SINIŠA MARKOV ◽  
JOVANA GRAHOVAC ◽  
MILA GRAHOVAC ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Carbon Source ◽  
Carbon Sources ◽  
Wild Type ◽  
Biotechnological Production ◽  
Aerobic Conditions ◽  
Pepper Leaves ◽  
Synthetic Media ◽  
Selection Of

In this study the screening of different Xanthomonas strains, isolated from infected crucifers and pepper leaves, for xanthan biosynthesis on semi-synthetic media containing different carbon sources was performed. The success of xanthan biosynthesis was estimated based on xanthan concentration in media and its molecular weight. Glucose and glycerol were investigated as carbon sources in a quantity of 20.0 g/L. Xanthan biosynthesis by different Xanthomonas isolates on two different cultivation media was carried out in Erlenmeyer flasks under aerobic conditions for 168 h. According to the obtained results selection of the carbon source, producing strain and their combination have a statistically significant effect on xanthan quantity and quality. The results obtained in this study indicate that local wild-type Xanthomonas strains isolated from pepper leaves have a great potential for application in biotechnological production of good-quality xanthan on glycerol-based media.

scholarly journals Growth and Flowering of ‘Alice du Pont’ Mandevilla in Response to Sumagic

1992 ◽  
Vol 10 (1) ◽  
pp. 36-39
Author(s):  
C. Frederick Deneke ◽  
Gary J. Keever ◽  
John A. McGuire
Keyword(s):  
Growth Rates ◽  
Vegetative Growth ◽  
Foliar Application ◽  
Application Rate ◽  
Single Application ◽  
Flower Diameter ◽  
Selection Of

Abstract Vegetative growth of ‘Alice du Pont’ mandevilla can be controlled by selection of an appropriate foliar application rate of Sumagic (uniconazole) and application interval. A single application of 5 to 20 ppm ai Sumagic (uniconazole) controlled vegetative growth for only 3 to 4 weeks; after this time, growth rates were similar to control plants. Multiple applications of 5 to 20 ppm ai Sumagic (uniconazole) effectively restricted vegetative growth; as the concentration of Sumagic (uniconazole) increased, the interval between applications increased from about 4 (5 ppm) to 6 (20 ppm) weeks. A single application of higher rates (30 to 120 ppm) of Sumagic (uniconazole) was phytotoxic. Generally, time to flowering increased and flower diameter decreased when application rate increased.

scholarly journals Contribution of Pretomanid to Novel Regimens Containing Bedaquiline with either Linezolid or Moxifloxacin and Pyrazinamide in Murine Models of Tuberculosis

2019 ◽  
Vol 63 (5) ◽  
Author(s):  
Jian Xu ◽  
Si-Yang Li ◽  
Deepak V. Almeida ◽  
Rokeya Tasneen ◽  
Kala Barnes-Boyle ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Mouse Models ◽  
Treatment Duration ◽  
Resistant Mutant ◽  
Murine Models ◽  
First Line ◽  
Independent Contribution ◽  
Resistant Mutants ◽  
Treatment Of Infection ◽  
Selection Of

ABSTRACT Novel regimens combining bedaquiline and pretomanid with either linezolid (BPaL regimen) or moxifloxacin and pyrazinamide (BPaMZ regimen) shorten the treatment duration needed to cure tuberculosis (TB) in BALB/c mice compared to that of the first-line regimen and have yielded promising results in initial clinical trials. However, the independent contribution of the investigational new drug pretomanid to the efficacy of BPaMZ has not been examined, and its contribution to BPaL has been examined only over the first 2 months of treatment. In the present study, the addition of pretomanid to BL increased bactericidal activity, prevented emergence of bedaquiline resistance, and shortened the duration needed to prevent relapse with drug-susceptible isolates by at least 2 months in BALB/c mice. Addition of pretomanid to bedaquiline, moxifloxacin, and pyrazinamide (BMZ) resulted in a 1-log10 greater CFU reduction after 1 month of treatment and/or reduced the number of mice relapsing in each of 2 experiments in BALB/c mice and in immunocompromised nude mice. Bedaquiline-resistant isolates were found at relapse in only one BMZ-treated nude mouse. Treatment of infection with a pyrazinamide-resistant mutant in BALB/c mice with BPaMZ prevented selection of bedaquiline-resistant mutants and reduced the proportion of mice relapsing compared to that for BMZ treatment alone. Among severely ill C3HeB/FeJ mice with caseous pneumonia and cavitation, BPaMZ increased median survival (≥60 versus 21 days) and reduced median lung CFU by 2.4 log10 at 1 month compared to the level for BMZ. In conclusion, in 3 different mouse models, pretomanid contributed significantly to the efficacy of the BPaMZ and BPaL regimens, including restricting the selection of bedaquiline-resistant mutants.

Sterol composition in polyene antibiotic-sensitive and resistant strains ofMalassezia pachydermatis

1994 ◽  
Vol 18 (3) ◽  
pp. 183-187 ◽  
Author(s):  
Y. Uchida ◽  
S. Onodera ◽  
T. Nakade ◽  
K. Otomo
Keyword(s):  
Sterol Composition ◽  
Polyene Antibiotic ◽  
Resistant Strains

Bacteriocin production by Pseudomonas syringae PsW-1 in plant tissue

1982 ◽  
Vol 28 (6) ◽  
pp. 600-604 ◽  
Author(s):  
Mary L. Smidt ◽  
Anne K. Vidaver
Keyword(s):  
Pseudomonas Syringae ◽  
Plant Tissue ◽  
Inner Core ◽  
Infected Plant ◽  
Resistant Mutant ◽  
Sensitive Strain ◽  
Bacteriocin Activity ◽  
Outer Sheath ◽  
Red Kidney Bean ◽  
20 Nm

The production and activity of syringacin W-1, a particulate bacteriocin made by Pseudomonas syringae PsW-1, was studied in plant tissue. The bacteriocin is rod shaped, approximately 20 nm wide and 75 nm long, and composed of an outer sheath and inner core. Both the producing strain, PsW-1, and a sensitive strain, 16, grew within red kidney bean stems. Strains PsW-1 and 16, or mutants derived from them, were injected into bean stems singly or in mixtures. All singly inoculated strains grew well. However, when the bacteriocin-producing strain was co-inoculated with the sensitive strain, the latter grew poorly, if at all. This was not due to competition for available nutrients, since the sensitive strain grew as well in the presence of a bacteriocin-nonproducing mutant as it did alone. Also, a bacteriocin-resistant mutant grew as well in the presence of the producing strain as it did alone. Bacteriocin activity and particles were recovered from infected plant tissue.

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