Studies on Aspergillus flavus—I. Factors influencing radiation resistance of non-germinating conidia

Padwal-Desai, S. R.; Ghanekar, A. S.; Sreenivasan, A.

doi:10.1016/0098-8472(76)90031-9

Cited by 13 publications

(2 citation statements)

References 14 publications

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“…The media used were nutrient agar (Oxoid). The over night culture of each organism was diluted with saline to contain 1 · 10 6 cell/mL for bacteria and 1 · 10 5 spores/mL for fungi (Padual-Desai et al, 1976). An aliquot of 3 mL of diluted culture was spread onto the surface of nutrient agar plate (40 mL each) and the excess bacterial suspension was withdrawn.…”

Section: Antimicrobial Assaymentioning

confidence: 99%

Rare trisubstituted sesquiterpenes daucanes from the wild Daucus carota

et al. 2005

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Section: Antimicrobial Assaymentioning

confidence: 99%

Rare trisubstituted sesquiterpenes daucanes from the wild Daucus carota

et al. 2005

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“…The harvesting of the spores from Roux bottles and preparation of the spore suspension (ca. 106 spores/mL) was carried out according to the method described earlier (Padwal-Desai et al, 1976).…”

Section: Preparation Of Spice Extracts Chloroform Extractsmentioning

confidence: 99%

Microbiological status and antifungal properties of irradiated spices

Sharma¹,

Ghanekar²,

Padwal-Desai³

et al. 1984

J. Agric. Food Chem.

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The bacterial counts of commercially available species were found to be in the range of 102-107/g, whereas the fungal counts varied between 102 and 103/g. Among the five spices studied, pepper, cardamom, and nutmeg mace had a high microbial load compared to cinnamon and clove. Exposure to -irradiation in the dose range of 7.5-10 kGy was adequate to sterilize all the spices. The essential oil of clove and cinnamon exhibited inhibitory properties against aflatoxin-producing aspergilli. -Irradiation did not affect fungal inhibitory principles present in clove, though marginal reduction was observed in that of cinnamon.

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On the relationship between pellet size and aflatoxin yield in Aspergillus parasiticus

Sharma

Padwal-Desai

1985

Biotech & Bioengineering

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In stationary cultures the spore number in inoculum was found to have an inverse relationship with the yield of aflatoxin, a secondary metabolite of Aspergillus fzavus and A. parasiticus.' However, in shake cultures, the mold grew in the form of pellets and the experimental yields of the metabolite were found to vary considerably depending on the size of the pellets. Earlier studies using 20-L fermentors suggested the use of small pellets for better yields, without studying the effect in detail.' Spore concentration in inoculum is recognized to influence the characteristics of pellet^.^ This communication therefore reports the relationship between spore number, pellet size, and yield of the toxin. MATERIALS AND METHODS Organism and Culture ConditionsThe aflatoxin-producing strain of A. parasiticus NRRL 3145 was used. The recultivation of the stock culture was carried out by streaking the slant material on potato-dextrose agar (Difco Laboratories, Detroit, MI) plates. Single colonies were picked up from streaked plates and transferred to potato-dextrose agar (PDA) slants. The spore suspension of the above cultures were prepared by transferring slant material to Roux bottles containing PDA (pH 5.6, 200 ml), which were subsequently incubated for 10 days at ambient temperature (28-30°C). The harvesting of spores from Roux bottles was carried out as described earlier., The synthetic growth medium contained (per liter): 20.0 g glucose, 6.0 g (NH,),SO,, 5.0 g KH2P0,, 0.5 g MgSO, .7H20, 2.0 g glycine, 2.0 g glutamic acid, 10.0 mg FeSO, . 7H20, 5.0 mg ZnSO, . 7H20, and 1.0 mg MnSO, . 7H20. The complete medium was prepared by mixing sterilized glucose solution with sterilized glucose-free salt solution. The pH of the medium was adjusted to 6.5. For inoculation 1-ml aliquots of either stock or serially diluted spore suspension were used.Incubation was carried out on a rotary shaker (150 rpm) at ambient temperature.The growth was determined by filtering the culture (Whatman No. 541), and drying the contents of the filter paper (85"C/6 h) before weighing. Extraction and Estimation of AflatoxinThe culture medium was separated from the mycelium, and the mycelium was ground separately in a mortar and pestle. The ground mycelium was mixed with the culture filtrate and the mixture was filtered through Whatman No. 541 paper. The resultant filtrate was treated with ferric gel (100 ml water, 10 ml of 10% ferric chloride solution plus 15 ml of 4.8% sodium hydroxide solution) to remove interfering pigments. The mixture was filtered through filter paper (Whatman No. 1). The filtrate was extracted with chloroform (two times the volume of filtrate). The extracts were evaporated in a water bath (SOT). and the residue so obtained was presented for estimation of aflatoxin.Total aflatoxin was estimated by using the microcolumn method of Velasco.' The microcolumn contained from bottom to top successive layers of sand, florisil, sand, silica gel, and alumina. The columns were wetted with chloroform before loading with the sample. The above res...

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Studies on Aspergillus flavus—I. Factors influencing radiation resistance of non-germinating conidia

Cited by 13 publications

References 14 publications

Rare trisubstituted sesquiterpenes daucanes from the wild Daucus carota

Rare trisubstituted sesquiterpenes daucanes from the wild Daucus carota

Microbiological status and antifungal properties of irradiated spices

On the relationship between pellet size and aflatoxin yield in Aspergillus parasiticus

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