THE USE OF AMMONIUM SOURCE OF NITROGEN IN THE METABOLISM OF ASPERGILLUS NIDULANS EIDAM

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.

1960 ◽  
Vol 38 (4) ◽  
pp. 613-622 ◽  
Author(s):  
Kaiser Naguib ◽  
Kamel Saddik

Aspergillus nidulans has been grown in surface culture on high-sugar media favorable for fat formation and containing, as nitrogen source, sodium nitrate, ammonium chloride, or asparagine. Growth, sugar and nitrogen uptake, and syntheses of carbohydrates, proteins, and fat were all followed over an incubation period of 20 days. In the early stages, growth was influenced by the nature of the nitrogen source, being highest on asparagine and lowest on ammonium chloride, with the same sugar uptake. Later, dry weight increase proceeded at a high rate on asparagine, at a moderate rate on sodium nitrate, and it almost stopped on ammonium chloride, where the pH dropped to a very low value. At this stage, increase in dry weight followed sugar absorption, and was due to accretion of non-nitrogenous compounds.Asparagine media were by far superior to nitrate or ammonium media for fat formation. Protein and carbohydrate contents were higher in nitrate- than in asparagine- or ammonium-fed mycelial felts. All synthetic processes almost stopped in ammonium cultures after the early growth phase. It seems that the attitude of the fungus towards ammonium nitrogen could not be fully manifested due to restricted growth, and therefore it is suggested that no definite conclusions with regard to ammonium utilization by Aspergillus nidulans can be drawn unless the pH of the medium is controlled and growth on ammonium nitrogen made possible.


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.


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.


1985 ◽  
Vol 54 (3) ◽  
pp. 567-575 ◽  
Author(s):  
H. C. Mehta ◽  
A. S. Saini ◽  
Harjit Singh ◽  
P. S. Dhatt

1. Sixty marasmic children were investigated for the absorption of xylose, proteins and fats. Their duodenal juice samples were also analysed for bile salts and microflora.2. The marasmic children were then studied in three groups of twenty by allocating them to three different dietary schedules: a high-protein diet (30% of the total energy from protein), a high-fat diet (40% of the total energy from fat) and a high-carbohydrate diet (70% of the total energy from carbohydrate) for 2 weeks and the previous measurements repeated.3. Whereas the high-fat diet resulted in improved fat absorption, along with an increase in total and conjugated bile acids, and the high-carbohydrate diet led to improved xylose absorption, the diet rich in protein resulted in an improvement in the absorption of all three dietary ingredients. It appears that a high-protein diet improves the overall absorption process by improving the intestinal environment as a whole, while high-carbohydrate and high-fat diets bring about adaptive changes related to the respective absorptive processes.


1998 ◽  
Vol 80 (1) ◽  
pp. 57-66 ◽  
Author(s):  
Sara L. Herd ◽  
Adrianne E. Hardman ◽  
Leslie H. Boobis ◽  
Caroline J. Cairns

The present study examined the influence of training, followed by a short period of detraining, on postprandial lipaemia. Fourteen normolipidaemic, recreationally active young adults aged 18–31 years participated, in two self-selected groups: three men and five women (BMI 21·7–27·6 kg/m2) completed 13 weeks of running training, after which they refrained from exercise for 9 d; three men and three women (BMI 21·5–25·6 kg/m2) maintained their usual lifestyle. Oral fat tolerance tests were conducted at baseline and again 15 h, 60 h and 9 d after the runners' last training session. Blood samples were drawn after an overnight fast and at intervals for 6 h after consumption of a high-fat meal (1·2 g fat, 1·4 g carbohydrate, 70·6 kJ energy/kg body mass). Heparin was then administered (100 IU/kg) and a further blood sample was drawn for measurement of plasma lipoprotein lipase (EC3.1.1.34; LPL) activity. Endurance fitness improved in runners, relative to controls (maximal O2uptake +3·2 (SE 1·1) ml/kg per minv.− 1·3 (SE 1·2) ml/kg per min; P < 0·05). In the absence of the acute effect of exercise, i.e. 60 h after the last training session, there was no effect of training on either postprandial lipaemia or on post-heparin LPL activity. However, changes during 9 d of detraining in both these variables differed significantly between groups; after 2 d without exercise (60 h test), the runners' lipaemic response was 37% higher than it was the morning after their last training session (15 h test; runnersv.controlsP< 0·05), with a reciprocal decrease in post-heparin LPL activity (P< 0·01). These findings suggest that improved fitness does not necessarily confer an effect on postprandial lipaemia above that attributable to a single session of exercise.


1989 ◽  
Vol 58 (6) ◽  
pp. 591-595 ◽  
Author(s):  
P. Satabin ◽  
B. Bois-Joyeux ◽  
M. Chanez ◽  
C. Y. Guezennec ◽  
J. Peret

2019 ◽  
Vol 25 ◽  
pp. 260-265
Author(s):  
E. V. Lagunovskaya ◽  
O. I. Zaitseva ◽  
V. A. Lemesh

Aim. Triticale is one of the main grain crops of the Republic of Belarus. Further progress in the selection of this culture involves the accelerated creation of highly productive early ripening varieties resistant to abiotic and biotic factors. The method of induced androgenesis in vitro makes it possible to obtain stable homozygous lines in a short period of time and to eliminate the lengthy process of inbreeding used in classical breeding to fix the desired traits. Methods. The tissue and cell culture methods for plants was used in the study. Results. The influence of the induction medium composition on the efficiency of in vitro induced androgenesis in varieties and lines of hexaploid triticale is assessed. The influence of three types of induction culture medium, the type of phytohormones and the presence or absence of cefotaxime in the medium are analyzed. Results. It has been shown that using the C-17 culture medium supplemented with 2.0 mg/l 2,4-D and 0.5 mg/l kinetin without adding cefotaxime is most effective for the anther triticale cultivation. Keywords: triticale, anther culture, induction nutrient medium, embryoids, calli, regenerant plants, cefotaxime.


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