Regulation of differentiation of the dimorphic fungusPaecilomyces viridis by nitrogen sources, antibiotics and metabolic inhibitors

1977 ◽  
Vol 22 (3) ◽  
pp. 222-231 ◽  
Author(s):  
H. Baráthová ◽  
V. Betina ◽  
L. Ulioký
1977 ◽  
Vol 23 (12) ◽  
pp. 1695-1699
Author(s):  
C. Obi Emeh ◽  
Elmer H. Marth

A sterile glucose–salts broth fortified with various metabolic inhibitors and nutritional supplements was inoculated with conidia of Penicillium rubrum P3290, and incubated quiescently at 28 °C for 14 days. Potassium sulfite and sodium metabisulfite at all test concentrations caused moderate reduction in rubratoxin formation; at high concentrations (≥2.7 × 10−2 M) accumulation of fungal tissue was also retarded. Production of rubratoxin and cell mass was inhibited by p-aminobenzoic acid; syntheses of toxin were completely blocked by 7.5 × 10−2 M of the vitamin. Effects of sodium fluoride on P. rubrum cultures grown on inorganic nitrogen sources varied from inhibition of mold growth and (or) rubratoxin A production to reduction in formation of rubratoxin B. With organic nitrogen sources, fluoride caused a 30 and 60% reduction in synthesis of rubratoxins A and B, respectively. Sodium acetate at all test concentrations enhanced formation of rubratoxin; mold growth was enhanced when acetate concentration was ≥6.0 × 10−2 M. A moderate reduction in mold growth was caused by lower acetate concentrations (1.2 × 10−2 M or 2.4 × 10−2 M). Sodium arsenite and iodoacetate at test concentrations blocked mold growth and toxin formation; sodium azide and 2,4-dinitrophenol caused a marked reduction in mold growth but inhibited toxin formation completely. However, sodium azide permitted slight growth and toxin formation when mold cultures were incubated for 28 days.


Author(s):  
Awtar Krishan ◽  
Dora Hsu

Cells exposed to antitumor plant alkaloids, vinblastine and vincristine sulfate have large proteinacious crystals and complexes of ribosomes, helical polyribosomes and electron-dense granular material (ribosomal complexes) in their cytoplasm, Binding of H3-colchicine by the in vivo crystals shows that they contain microtubular proteins. Association of ribosomal complexes with the crystals suggests that these structures may be interrelated.In the present study cultured human leukemic lymphoblasts (CCRF-CEM), were incubated with protein and RNA-synthesis inhibitors, p. fluorophenylalanine, puromycin, cycloheximide or actinomycin-D before the addition of crystal-inducing doses of vinblastine to the culture medium. None of these compounds could completely prevent the formation of the ribosomal complexes or the crystals. However, in cells pre-incubated with puromycin, cycloheximide, or actinomycin-D, a reduction in the number and size of the ribosomal complexes was seen. Large helical polyribosomes were absent in the ribosomal complexes of cells treated with puromycin, while in cells exposed to cycloheximide, there was an apparent reduction in the number of ribosomes associated with the ribosomal complexes (Fig. 2).


1984 ◽  
Vol 51 (01) ◽  
pp. 119-124 ◽  
Author(s):  
M B Zucker ◽  
N C Masiello

SummaryMacIntyre et al. showed that over 1 mM dithiothreitol (DTT) aggregates blood platelets in the presence of fibrinogen; aggregation is not inhibited by prostaglandin E1. We confirmed their data and found that 70 mM 2-mercaptoethanol was also active. DTT- induced aggregation was not associated with platelet shape change or secretion of dense granule contents, was not inhibited by tetracaine or metabolic inhibitors, was prevented at pH 6.5, and prevented, reversed, or arrested by EDTA, depending on when the EDTA was added. DTT did not cause aggregation of thrombasthenic, EDTA-treated, or cold (0° C) platelets, which also failed to aggregate with ADP. Platelets stimulated with DTT bound 125I-labeled fibrinogen. Thus DTT appears to “expose” the fibrinogen receptors. SDS gel electrophoresis of platelet fractions prepared by use of Triton X-114 showed that aggregating concentrations of DTT reduced proteins of apparent Mr 69,000 and 52,000 (probably platelet albumin) and, to a variable extent, glycoproteins Ib, IIb and III. Exposure of unlabeled or 125I- labeled platelets to ADP had no discernible effect on the electrophoretic patterns.


2016 ◽  
Vol 549 ◽  
pp. 79-88 ◽  
Author(s):  
AJ Hirst ◽  
AR Longmore ◽  
D Ball ◽  
PLM Cook ◽  
GP Jenkins

2012 ◽  
Vol 2 (7) ◽  
pp. 424-426
Author(s):  
Suchita Dahiwade ◽  
◽  
Dr. A. O. Ingle Dr. A. O. Ingle ◽  
Dr. S. R. Wate Dr. S. R. Wate

2019 ◽  
Vol 57 (6) ◽  
pp. 665 ◽  
Author(s):  
Yen Thi Hoang ◽  
Quynh Thi Thu Tran ◽  
Ha Hoang Chu ◽  
Tuyen Thi Do ◽  
Thanh Tat Dang ◽  
...  

Purple nonsulfur bacteria are a group that has so much biotechnological applications, particularly in producing of functional food rich with unsaturated fatty acids. A purple nonsulfur bacterium (named HPB.6) was chosen based on its strong growth, high lipid and synthesis of unsaturated fatty acid (omega 6,7,9). Studying on basic biological characteristics showed that the cells of HPB.6 were observed as ovoid-rod shape, none motility, Gram negative staining. The diameter of single bacterium was about 0.8-1.0 µm. The cells divide by binary fission and had bacteriochlorophyll a (Bchl a). This bacterium grew well on medium with carbon and nitrogen sources such as acetate, succinate, pyruvate, butyrate, glutamate, arginine, leucine, tyrosine, alanine, methionine, threonine, glutamine, yeast extract and NH4Cl. This selected strain grew well on medium with salt concentrations from 1.5 - 6.0% (optimum 3%), pH from 5.0 to 8.0 (optimum at pH 6.5) and could withstand Na2S at 4.0 - 5.2 mM. Based on morphological, physiological properties and 16S rRNA analysis received demonstrated that HPB.6 strain belongs to the species Rhodovulum sulfidophilum.


1959 ◽  
Vol 18 (2) ◽  
pp. 780-789 ◽  
Author(s):  
C. D. Campbell ◽  
G. A. McLaren ◽  
G. C. Anderson ◽  
J. A. Welch ◽  
G. S. Smith ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document