Some nutritional and environmental factors affecting growth and production of sclerotia by a strain of Aspergillus niger

1969 ◽  
Vol 15 (8) ◽  
pp. 835-840 ◽  
Author(s):  
V. P. Agnihotri
Keyword(s):  
Aspergillus Niger ◽  
Environmental Factors ◽  
Synergistic Effect ◽  
Magnesium Sulfate ◽  
Sodium Sulfite ◽  
Agar Medium ◽  
Carbon Sources ◽  
Dry Weight ◽  
Factors Affecting ◽  
Nutritional Elements

The effects of two nutritional elements (carbon and sulfur) and two environmental factors (pH and temperature) on growth and sclerotial production of Aspergillus niger were determined on a synthetic agar medium. The fungus grew and produced sclerotia under laboratory conditions on media containing wide ranges of carbon and sulfur sources. Of the 20 carbohydrates tested, only ribose, mannitol, and malonic, fumaric, and citric acids failed to induce production of sclerotia. A synergistic effect was observed on the formation of sclerotia when favorable and unfavorable carbon sources were supplied in different combinations. Of the 14 sulfur compounds tested, magnesium sulfate yielded the highest and sodium sulfite the lowest number of sclerotia. Raising the concentration of magnesium sulfate to 3 g/l increased the number of sclerotium initials and the number and dry weight of those which matured. In general, no correlation occurred between the number of sclerotia formed and their dry weights on different carbon or sulfur sources. Sclerotia were most numerous at pH 7.0 and 35 °C.

Factors Influencing Geosmin Production by the Cyanobacterium Oscillatoria Brevis

1988 ◽  
Vol 20 (8-9) ◽  
pp. 125-131 ◽  
Author(s):  
H. Naes ◽  
H. C. Utkilen ◽  
A. F. Post
Keyword(s):  
Environmental Factors ◽  
Dry Weight ◽  
Growth Conditions ◽  
Limited Extent ◽  
Limited Growth ◽  
Pigment Synthesis ◽  
Factors Affecting ◽  
Culture Techniques ◽  
Factors Influencing ◽  
Effect Of Inhibitors

Environmental factors affecting geosmin production by Oscillatoria brevis have been investigated under laboratory conditions using continuous culture techniques. Transition from light to nutrient limited growth conditions caused a two-fold decrease in geosmin production. However, geosmin content increased relative to pigment content (chlorophyll a and carotenoids). It has been suggested that geosmin biosynthesis in O. brevis proceeds via the isoprenoid pathway as was found in actinomycetes. Accordingly, we investigated the effect of inhibitors of the intermediate stages in this synthetic pathway in order to study the regulation of geosmin production in relation to pigment synthesis. It was concluded that geosmin seemed to function as an overflow metabolite in this pathway. Due to the only modest changes in geosmin production per dry weight compared to changes in biomass levels during light- or nutrient limited growth, contamination of eutrophic fresh waters with geosmin appears to depend mainly on the species present and its biomass level and only to a limited extent on nutrient enhanced synthesis.

scholarly journals Weed infestation and factors affecting weed incidence in spring cereals in Finland - a multivariate approach

1993 ◽  
Vol 2 (6) ◽  
pp. 525-536 ◽  
Author(s):  
Jukka Salonen
Keyword(s):  
Environmental Factors ◽  
Correspondence Analysis ◽  
Dry Weight ◽  
Organic Soils ◽  
Weed Species ◽  
Data Set ◽  
Factors Affecting ◽  
Geographical Regions ◽  
Weed Flora ◽  
Weed Infestation

Weed vegetation of spring cereal fields in southern and central Finland was analyzed by ordination methods to provide a community level description of weed populations. Attention was paid particularly to the relative importance of environmental factors affecting weed incidence such as crop management, soil properties and weather conditions. A data set of 33 weed taxa from 252 fields was subjected to both indirect and direct gradient analysis. Indirect ordination was obtained with correspondence analysis (CA), and direct gradient analyses were performed with redundancy analysis (RDA) and with canonical correspondence analysis (CCA) relating environmental factors to the occurrence of weeds. Among several management factors, continuous herbicide use explained best the variation in the species composition of weed flora. Weed vegetation was also associated with soil type, moisture conditions and soil pHH2O. Ordination diagrams visualized the species-environment interactions and detected characteristic weed species for different geographical regions. In addition to ordination analyses of weed flora, the level and structure of weed infestation are described. The density of weeds averaged 170 plants m2 (median=124) and the air-dry weight of weeds 320 kg ha-1 (median=183). The average weed density was the same in different soil types, but the weed biomass was lower in clay soils than in coarse mineral and organic soils

Nutritional and environmental factors affecting growth and sporulation of Sporidesmium sclerotivorum

1981 ◽  
Vol 27 (7) ◽  
pp. 685-691 ◽  
Author(s):  
E. A. Barnett ◽  
W. A. Ayers
Keyword(s):  
Nitrogen Source ◽  
Agar Medium ◽  
Carbon Sources ◽  
Nitrogen Sources ◽  
Mineral Salts ◽  
Factors Affecting ◽  
Carbon And Nitrogen ◽  
Naoh Solution ◽  
Casamino Acids ◽  
Nutritional Studies

Three of five isolates of Sporidesmium sclerotivorum, a mycoparasite of Sclerotinia spp., grew well on an agar medium containing mineral salts, glucose, thiamine, and glutamine or Casamino acids as the nitrogen source. The nitrogen requirement for two of the isolates was satisfied by NH4Cl, Casamino acids, or glutamine. Glutamine was the best single nitrogen source. Only one isolate, CS-1, was used in further nutritional studies. The optimum concentration of glutamine for growth was 5 g/L. Glucose, mannose, mannitol, and cellobiose were excellent carbon sources. A glucose concentration of 20 g/L was optimum. Mannitol supported greater growth than glucose with Casamino acids as the nitrogen source but glucose was the superior carbon source with glutamine as the nitrogen source. Greatest growth was achieved with a combination of these carbon and nitrogen sources. Sporidesmium sclerotivorum, isolate CS-1, required thiamine for growth and sporulation. Biotin stimulated growth. The fungus developed maximally within the range of pH 5.0–5.5 and growth was greatly reduced at a pH below 4.0 or above 6.0. Control of acidity by the periodic addition of NaOH solution permitted substantially increased growth. The optimum temperature for growth was 22.5–25.0 °C but production of macroconidia was greatest at 15–20 °C.

Environmental factors affecting the antagonism of Pseudomonas cepacia against Trichoderma viride

1991 ◽  
Vol 37 (11) ◽  
pp. 880-884 ◽  
Author(s):  
Ram S. Upadhyay ◽  
Luisa Visintin ◽  
R. K. Jayaswal
Keyword(s):  
Antifungal Activity ◽  
Environmental Factors ◽  
Key Words ◽  
Environmental Conditions ◽  
Trichoderma Viride ◽  
Carbon Sources ◽  
Ammonium Nitrogen ◽  
Antagonistic Activity ◽  
Pseudomonas Cepacia ◽  
Factors Affecting

Antagonistic activity of the bacterium Pseudomonas cepacia against Trichoderma viride was greatly influenced by nutritional and environmental conditions. Xylose and trehalose strongly enhanced the antifungal activity of P. cepacia, whereas mannitol and glucose had little effect. The carbon sources that enhanced the antagonistic activity also inhibited sporulation of T. viride. Antagonism of P. cepacia was enhanced by ammonium nitrogen; however, with nitrite or nitrate there was only a little antagonism. The antagonism of P. cepacia was optimal at pH 5.0. Although P. cepacia showed maximum antagonism against T. viride at 37 °C, the antagonism was fairly good at temperatures as low as 18 °C, indicating that there is a broad range of temperature for the antifungal activity of P. cepacia. Key words: antagonism, environmental factors, Pseudomonas cepacia, Trichoderma viride.

Environmental factors affecting reproducibility of bioremediation field assays in Antarctica

2020 ◽  
Vol 169 ◽  
pp. 102915 ◽  
Author(s):  
L.M. Martínez Álvarez ◽  
L.A.M. Ruberto ◽  
J.M. Gurevich ◽  
W.P. Mac Cormack
Keyword(s):  
Environmental Factors ◽  
Factors Affecting
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