0.02 M Monobasic Potassium Phosphate TS

1970 ◽  
Vol 16 (1) ◽  
pp. 29-32 ◽  
Author(s):  
A. A. Qureshi ◽  
O. T. Page

An isolate of Fusarium oxysporum grown in a solution of monobasic potassium phosphate and magnesium sulfate rarely produced chlamydospores. However, when the salt solution was amended with 0.125 mg to 2.0 mg per liter of either glucose or magnesium carbonate, there was an abundant production of chlamydospores within 3 to 4 days after inoculation. While an organic or inorganic source of carbon stimulated chlamydospore formation, repression of chlamydospore production occurred with glucose and magnesium carbonate levels above 2.0 mg per liter. The addition of either an ammonium or nitrate source of nitrogen to the salt solution did not produce additional chlamydospores.


2006 ◽  
Vol 25 (1) ◽  
pp. 70-77 ◽  
Author(s):  
Joyce C. Wong ◽  
Albert R. McDougal ◽  
Marianne Tofan ◽  
Jasvinder Aulakh ◽  
Marjolan Pineault ◽  
...  

Author(s):  
M. H. Wheeler ◽  
W. J. Tolmsoff ◽  
A. A. Bell

(+)-Scytalone [3,4-dihydro-3,6,8-trihydroxy-l-(2Hj-naphthalenone] and 1,8-di- hydroxynaphthalene (DHN) have been proposed as intermediates of melanin synthesis in the fungi Verticillium dahliae (1, 2, 3, 4) and Thielaviopsis basicola (4, 5). Scytalone is enzymatically dehydrated by V. dahliae to 1,3,8-trihydroxynaphthalene which is then reduced to (-)-vermelone [(-)-3,4- dihydro-3,8-dihydroxy-1(2H)-naphthalenone]. Vermelone is subsequently dehydrated to DHN which is enzymatically polymerized to melanin.Melanin formation in Curvularia sp., Alternaria sp., and Drechslera soro- kiniana was examined by light and electron-transmission microscopy. Wild-type isolates of each fungus were compared with albino mutants before and after treatment with 1 mM scytalone or 0.1 mM DHN in 50 mM potassium phosphate buffer, pH 7.0. Both chemicals were converted to dark pigments in the walls of hyphae and conidia of the albino mutants. The darkened cells were similar in appearance to corresponding cells of the wild types under the light microscope.


Author(s):  
S. S. Breese ◽  
H. L. Bachrach

Models for the structure of foot-and-mouth disease virus (FMDV) have been proposed from chemical and physical measurements (Brown, et al., 1970; Talbot and Brown, 1972; Strohmaier and Adam, 1976) and from rotational image-enhancement electron microscopy (Breese, et al., 1965). In this report we examine the surface structure of FMDV particles by high resolution electron microscopy and compare it with that of particles in which the outermost capsid protein VP3 (ca. 30, 000 daltons) has been split into smaller segments, two of which VP3a and VP3b have molecular weights of about 15, 000 daltons (Bachrach, et al., 1975).Highly purified and concentrated type A12, strain 119 FMDV (5 mg/ml) was prepared as previously described (Bachrach, et al., 1964) and stored at 4°C in 0. 2 M KC1-0. 5 M potassium phosphate buffer at pH 7. 5. For electron microscopy, 1. 0 ml samples of purified virus and trypsin-treated virus were dialyzed at 4°C against 0. 2 M NH4OAC at pH 7. 3, deposited onto carbonized formvar-coated copper screens and stained with phosphotungstic acid, pH 7. 3.


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