Two varieties of Rhizophydium sphaerocarpum (Chytridiales)

1970 ◽  
Vol 48 (6) ◽  
pp. 1067-1071 ◽  
Author(s):  
D. J. S. Barr

Two varieties of Rhizophydium sphaerocarpum (Zopf) Fischer are proposed: var. sphaerocarpum, saprophytic on algae, nematodes, and pine pollen; and var. spirogyrae, a parasite of Spirogyra spp. The varieties differ morphologically only in colony color and texture. Variety sphaerocarpum grew best at (10–) 15–20 C and used inorganic nitrogen as ammonium chloride, ammonium nitrate, and sodium nitrate when the inoculum contained actively growing thalli, whereas var. spirogyrae grew best at (25–) 30 C and did not use inorganic nitrogen. Results of pH range tests and carbon nutrition were very similar for the two varieties and both required exogenous thiamine.

1961 ◽  
Vol 39 (4) ◽  
pp. 955-964 ◽  
Author(s):  
Kaiser Naguib ◽  
Kamel Saddik

Aspergillus nidulans was grown as surface cultures on three ammonium salts, namely: ammonium chloride, ammonium carbonate, and ammonium nitrate in a basal medium favorable for fat formation. It was also grown on sodium nitrate for comparison. Growth, uptake of sugar and nitrogen, fat and protein syntheses, and pH change in the culture media were all followed over an incubation period of 20 days at 25° C.Growth on ammonium chloride was suppressed after a short period, when the pH of the medium dropped to a very low value. Mycelial felts had high protein contents but insignificant amounts of fat. In ammonium carbonate cultures, fungal growth continued yielding heavy mycelial felts with high fat content. But nitrogen utilization ceased while an ample supply was still present in the culture medium leading to low protein content in the mycelial felts. This could not be attributed to any drastic change in the pH of the culture medium; the pH changed only within reasonable limits.Growth was best on ammonium nitrate. Mycelial felts contained high protein and high fat. The change in pH of the medium, during the early period of incubation, indicated preferential absorption of ammonium to nitrate ions. Growth on sodium nitrate started by a lag period, but soon became active and gave rise to a heavy mycelium.The present findings also showed that nitrate nitrogen was more conducive to protein synthesis by Aspergillus nidulans than was ammonium nitrogen. Fat formation, on the other hand, was lower on sodium nitrate than on ammonium carbonate or ammonium nitrate.


2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
B. M. Vastrad ◽  
S. E. Neelagund

Neomycin production of Streptomyces fradiae NCIM 2418 was optimized by using response surface methodology (RSM), which is powerful mathematical approach comprehensively applied in the optimization of solid state fermentation processes. In the first step of optimization, with Placket-Burman design, ammonium chloride, sodium nitrate, L-histidine, and ammonium nitrate were established to be the crucial nutritional factors affecting neomycin production significantly. In the second step, a 24 full factorial central composite design and RSM were applied to determine the optimal concentration of significant variable. A second-order polynomial was determined by the multiple regression analysis of the experimental data. The optimum values for the important nutrients for the maximum were obtained as follows: ammonium chloride 2.00%, sodium nitrate 1.50%, L-histidine 0.250%, and ammonium nitrate 0.250% with a predicted value of maximum neomycin production of 20,000 g kg−1 dry coconut oil cake. Under the optimal condition, the practical neomycin production was 19,642 g kg−1 dry coconut oil cake. The determination coefficient (R2) was 0.9232, which ensures an acceptable admissibility of the model.


1988 ◽  
Vol 68 (1) ◽  
pp. 63-75 ◽  
Author(s):  
LEONARD J. EATON ◽  
DAVID G. PATRIQUIN

Soil ammonium and nitrate in the top 15 cm of soil were monitored after application of ammonium nitrate and ammonium sulfate to plots at 14 PF (previously fertilized) and 12 NF (never fertilized) lowbush blueberry (Vaccinium angustifolium Ait.) stands representing a range of soil types and management histories. Overall, nitrate values in unfertilized and ammonium sulfate plots were higher at PF than at NF sites, suggesting greater nitrification at PF sites. In laboratory incubation studies, nitrification proceeded immediately in soil from a PF site, but only after a 4-wk lag in that from an adjacent NF site. Nitrification rates were low compared to that in a garden soil (pH 6.6). N-Serve inhibited nitrification in both soils. In ammonium nitrate plots, "excess" N values (N values in fertilized plots minus values in unfertilized plots) were higher for PF than for NF sites, suggesting greater immobilization, plant uptake or loss of N at NF sites. There was no evidence, in laboratory studies, of immobilization of added N by soil from either type of site. Rhizome N concentration increased significantly in response to fertilization at an NF site, but not at a PF site. Key words: Blueberry (lowbush), fertilizer and soil nitrogen


Ecotoxicology ◽  
2017 ◽  
Vol 26 (5) ◽  
pp. 667-674 ◽  
Author(s):  
Núria Garriga ◽  
A. Montori ◽  
G. A. Llorente

1989 ◽  
Vol 23 (7) ◽  
pp. 1591-1599 ◽  
Author(s):  
A.G. Allen ◽  
Roy M. Harrison ◽  
Jan-Willem Erisman

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