Authors:R. Srinivasan, V. Shanmugam, A. Kamalakannan and M. Surendran
Aspergillus niger was found to be the predominant pathogen associated with black mould rot of onion during storage. Market survey for the assessment of spoilage caused by the fungus recorded a loss of 2.9% to 12.09% during the period from June 1998 to February 1999. Application of higher doses of calcium in the form of gypsum (400 kg/ha) and lower dose of nitrogen in the form of urea (50 kg/ha) to the field and advancing the harvest of onion bulbs by fifteen days significantly reduced the spoilage of bulbs during storage. An inverse relationship existed between neck length of the bulbs and spoilage at storage. Bulb rotting was noticed when the storage temperature was between 30 °C and 40 °C and the relative humidity was above 80%. Further, A. niger infection caused reduction in pungency of onion bulbs which was more pronounced at grade 4 than grade 1. The culture filtrates of Aspergillus niger and Aspergillus flavus isolated from onion as well as the extracts from onion bulbs infected with the above fungi were free from aflatoxin contamination.
Authors:Y. Bakri, Y. Akeed, M. Jawhar and M.I.E Arabi
this study ( Table 1 ). Two local Aspergillus strains, A. terreus (Fss 129) and A. niger (SS7), isolated from soil by BBAKRI and co-workers (2010), were used. The saprophyte Penicillium canescens strain F58 from the Institute of Plant
Authors:Mohammed Rifaat Ahmed, Ashraf Saad Abou-Halawa, Waheed F. Hessam and Diaa’ Salaheldin Aly Abdelkader
culture and fungal smear was performed. The most common fungal isolates were A. fumigatus in 23 cases (37%), A. niger in 17 cases (27%), and Candida albicans in 13 cases (21%). A. flavus was isolated in four cases (6%), Aspergillus terreus in
Authors:E. Sedaghati, M. Nikkhah, R. Zare, K. Fotuhifar, S. Kocsubé, Cs. Vágvölgyi and J. Varga
Ochratoxin A is a mycotoxin produced by Aspergillus and Penicillium species. This mycotoxin is a common contaminant of various foods including cereal products, spices, dried fruits, coffee, beer and wine. Besides species assigned to Aspergillus section Circumdati, black Aspergilli including A. niger, A. carbonarius and A. sclerotioniger are also able to produce this mycotoxin. Black Aspergilli have been found to be the predominant fungi contaminating pistachio nuts worldwide. We examined the species distribution of black Aspergilli on Iranian pistachio nuts. Sequence-based identifications have been carried out using partial calmodulin sequence data. Our data indicate that instead of the potential ochratoxin and fumonisin producing A. niger species, A. tubingensis dominates on Iranian pistachio nuts. This species is unable to produce either of these mycotoxins, consequently do not contribute to mycotoxin contamination of pistachio nuts in Iran. Further studies are in progress to clarify the role of other Aspergilli in ochratoxin contamination of pistachio in Iran.
The exudates of three fungal species (Aspergillus niger, Fusarium sambucinum and Penicillium canescens) have been tested for their effect on the algal population and diversity of El-Ibrahemia Canal. It has been found that the exudates of F. sambucinum was stimulatory for the algal population, whereas that of A. niger was inhibitory. Penicillium canscens exudate, in comparison, displayed the weakest effect. The results imply a great variation in the effectiveness of different types of fungal exudates on the different algal taxa. Chlorella fusca has been studied intensively, because it was the only chlorophycean species that survived and tolerated all applied concentration of the exudates of the three studied fungi. The growth of C. fusca has been enhanced by F. sambucinum exudates, but not by that of A. niger. The effect of fungal exudates on some metabolic components of C. fusca is discussed.
Antifungal effect of Micromeria myrtifolia Boiss. & Hohen. in Boiss. and Prangos uechtritzii Boiss. Hawsskn decoctions was tested against Alternaria alternata, Aspergillus niger, Aspergillus parasiticus, Botrytis cinerea, Fusarium oxysporum f.sp. melonis and Penicillium digitatum. Of the 2 substances tested Pr. uechtritzii, being present at 75 to 80% concentration in potato dextrose agar, partly inhibited growth of A. alternata, B. cinerea and P. digitatum. Pr. uechtritzii had higher antifungal effect than M. myrtifolia on mycelial growth during incubation. M. myrtifolia partly affected mycelial growth of A. alternata and A. niger at the beginning of incubation. But the mycelial growth of F. oxysporum was not inhibited by M. myrtifolia concentrations during incubation. Also, Pr. uechtritzii did not have any affect on mycelial growth of A. niger during incubation P. digitatum, the most sensitive microorganism to both decoctions. Higher decoction concentrations of plants used in study will be probably inhibit mycelial growth of microorganisms.
Five mushroom species, P. ostreatus, P. ostreatus var. salignus, P. eryngii, P. florida, P. sajor-caju, threecontaminant fungi A. niger, P. italicum, R. stonolifera, andbarley, sorghum and wheat grains were used in the study. The purpose of this work was to determine mycelial growth of Pleurotus spp. and their competition with contaminant fungi. The Pleurotus spp. were grown better on the sorghum grains than the barley and wheat grains according to mycelial growth and density. The colony growth of Pleurotus spp.was inhibited by A. niger, P. italicum and R. stonolifera by 13.84%, -1.58% and 24.48%; 9.84%, 20.31% and 18.06%; 14.48%, 100.00% and 100.00% on the 3 rd, 5 th and 7 th days after inoculation, respectively.The mushroomswere completely suppressed by R. stonolifera on the 5 th day.
Authors:Yuanyou Yang, Ning Liu, Shunzhong Luo, Jiali Liao, Jiannan Jin, Taiming Zhang and Pengji Zhao
Biosorption of 241Am by a fungus A. niger, including the spore and hyphae, was investigated. The preliminary results showed that the adsorption of 241Am by the microorganism was efficient. More than 96% of the total 241Am could be removed from 241Am solutions of 5.6-111 MBq/l (Co) by spore and hyphaeof A. niger, with adsorbed 241Am metal (Q) of 7.2-142.4 MBq/g biomass, and 5.2-106.5 MBq/g, respectively. The biosorption equilibrium was achieved within 1 hour and
the optimum pH range was pH 1-3. No obvious effects on 241Am adsorption by the fungus were observed at 10-45 °C, or in solutions containing Au3+ or Ag+, even 2000 times above the 241Am concentration. The 241Am biosorption by the fungus obeys the Freundlich adsorption equation. There was no significant difference between the adsorption
behavior of A. nigerspore and hyphae.
Rhizosphere and rhizoplane of fababean (Vicia faba), melochia (Corchorus olitorius), sesame (Sesamum indicum) and soyabean (Glycine max) plants are inhabited with fungi, mostly Aspergillus flavus, A. niger, Fusarium oxysporum, Penicillium corylophilum, P. cyclopium, P. funiculosum and Rhizopus stolonifer. All fungal species have the ability to produce gibberellin (GA) but F. oxysporum was found to produce both GA and indole-acetic acid (IAA). The optimum period for GA and IAA production by F. oxysporum was 10 days in the mycelium and 15 days in the filtrate at 28 °C. The contents of GA, IAA and cytochrome P-450 were increased at 0.5 and 1% NaCl after 5 days, but GA and IAA were lowered at 4% (700 mM) NaCl. Calcium decreased NaCl stress on F. oxysporum by significant elevating GA biosynthesis at 40mM Ca2+/700 mM Na+. GA at 10 mM and Ca2+ at 10 mM enhanced the germination of seeds under 175 mM Na+.