Survey of Aspergillus species associated with the human respiratory tract

A comprehensive survey has been carried out on the occurrence ofAspergillus species in the respiratory tract of patients of bronchopulmonary diseases in Delhi. In all, 1238 clinical specimens, which included 1082 sputa, 143 bronchial aspirates and 13 throat swabs obtained from 812 patients, were examined. Of these 61.7 per cent patients were culturally positive yielding 29 different species ofAspergillus. The prevalence of aspergilli in sputa was significantly higher than in the bronchial aspirates.Aspergillus niger was the commonest species isolated showing a prevalence of 36.7 per cent. It was followed byA. flavus, A. nidulans, A. terreus, A. versicolor, A. sydowi, A. japonicus andA. oryzae. None of theAspergillus species showed a significant correlation with any of the diseases, or the type of treatment the patients had received. Of the 8 broad occupational groups investigated farmers and labourers showed higher prevalence ofA. niger andA. flavus. The prevalence ofAspergillus species in the throats of healthy persons was 16 per cent withA. versicolor being the commonest species followed byA. flavus, A. amstelodami, A. sydowi andA. terreus. A comparison of the prevalence ofAspergillus species in the patients, healthy individuals and atmosphere of Delhi appears to support the view that the aspergilli are transient residents in the human respiratory tract following their inhalation from the environment.     

Survey of the mycoflora and mycotoxins of cotton seeds and cotton seed products in Egypt

Thirty-nine species and 16 fungal genera were isolated from Egyptian cotton seeds, cotton seed meal and cotton seed cake on 1% glucose-Czapek's agar medium incubated at 28 °C. Aspergillus was the most frequent genus and it emerged in 87–100% of the samples contributing 70–98% of total fungi in the three substrates tested. The most common species were A. niger, A. flavus, A. fumigatus, A. terreus and Rhizopus stolonifer; A. niger, A. fumigatus and Penicillium corylophilum; and A. niger, A. flavus, A. terreus, A. nidulans and Rhizopus stolonifer, respectively. Cotton seeds and cotton seed products were naturally contaminated by aflatoxin B₁ and B₂. About 16% of the different substrates tested were positive for aflatoxin contamination. No citrinin, ochratoxin A, patulin, sterigmatocystin, diacetoxyscirpenol, T-2 toxin or zearalenone were detected in the samples assayed.     

Production of mycelial protein and cellulolytic enzymes from food wastes

Summary Extracted grape waster material and pressed apple pulp were tested as carbon sources forPenicillium funiculosum 515,Myrothecium verrucaria 9095 andAspergillus niger TMF-15. They were good growth substrates, especially forA. niger. When cultivated on mixed substrate in optimized nutrient medium,A. niger accumulated a product of 35% crude protein with a maximum productivity of 0.117 g protein/1/h and cellulose consumption of 90.92%.A. niger also produced the highest levels of cellulase activity. Maximum carboxymethyl cellulase and activity against filter paper were 494 units/l and 97 units/l, respectively.     

Effect of some common rhizosphere fungi on root growth of seedlings

Summary The effect of some common rhizosphere fungiviz Aspergillus niger, A. terreus, A. flavus, Fusarium nivale, Cunninghamella echinulata, Trichoderma viride andPaecilomyces fusisporus on the root growth of seedlings ofDichanthium annulatum andSetaria glauca was studied. The seedlings grown in modified Crone's nutrient medium were inoculated with the test fungi. In uninoculated control tubes, seedlings showed normal root growth. The different fungi exceptF. nivale were found to reduce root growth considerably. WithA. niger besides reduction in root length, the leaves of the seedlings were found to turn yellow. The reduction in root growth in the presence of fungi was statistically significant.     

Amylase synthesis inAspergillus flavus andAspergillus niger grown on cassava peel

Summary Aspergillus flavus andAspergillus niger produce extracellular amylase into the culture medium when grown on basal medium containing 2% (w/v) soluble starch or cassava peel as the sole carbon source. On soluble tarch the highest amylase activities were 1.6 and 5.2 mg of starch hydrolyzed/min per mg protein forA. flavus andA. niger, respectively. When grown on cassava peel, the highest amylase activity in the culture filtrate ofA. flavus was 170-times higher than that on soluble starch, while that ofA. niger was 16-times higher. The mycelial dry weight for both organisms was not significantly affected by the carbon sources. Maximum enzyme activity was obtained at the growth temperature of 29.0±1°C and pH 7 for both organisms. It is concluded that cassava peel might be a better substrate for the production of amylase byA. flavus andA. niger than commercial soluble starch.     

An analysis of interspecific relationships ofSaguinus based on cranial measurements

The interspecific relationships of the following nine forms ofSaguinus were analyzed applying the multivariate analysis to the cranial measurements;S. oedipus, S. geoffroyi, S. leucopus, S. nigricollis, S. fuscicollis, S. labiatus, S. mystax, S. midas midas, andS. midas niger. Penrose's size distance was used to express the size factor among the nine forms; and for the shape factor, Q-mode correlation coefficients were utilized. The shape distance betweenS. oedipus andS. geoffroyi was almost equal to that betweenS. nigricollis andS. fuscicollis which are recognized as different species based on biogeographical evidence. Furthermore, the Penrose's size distance betweenS. oedipus andS. geoffroyi was quite large. Therefore, the results of this study support the hypothesis thatS. oedipus andS. geoffroyi are valid species. The analysis of the phylogenetic relationships among the nine forms was based on the shape factor only. The forms were divided into two main clusters: (1)S. oedipus, S. geoffroyi, andS. leucopus; (2)S. nigricollis, S. fuscicollis, S. labiatus, S. mystax, S. midas midas, andS. midas niger. In the former cluster,S. oedipus was more closely related toS. geoffroyi than either was toS. leucopus. The latter cluster was subdivided in two subclusters based on the degree of their affinity: (2a)S. nigricollis, S. fuscicollis, S. labiatus, andS. mystax; and (2b)S. midas midas andS. midas niger. In the former subcluster, [S. nigricollis, S. fuscicollis] and [S. labiatus, S. mystax] were classified into clusters, respectively. The ancestor of theS. nigricollis group differentiated intoS. oedipus, S. geoffroyi, andS. leucopus with the narrowing of the maxilla in the facial region, andS. midas midas andS. midas niger with the downward movement of rhinion.     

Studies on aspergilli. VI. The utilization of amino acids in mixtures by some ascosporic members of the aspergillus nidulans group

Summary The utilization of certain amino acids when supplied in three different combinations, (a) glycine, serine, valine, histidine (b) methionine, valine, alanine, arginine (c) leucine, tryptophane, glutamic acid, aspartic acid, byA. nidulans (Eidam)Wint;A. rugulosus Thom andRaper;A. variecolor (Berk. andBr.)Thom andRaper;A. quadrilineatus Thom andRaper andA. violaceus Fennel andRaper was studied through circular partition chromatography. It was found that these Aspergilli which are so closely related morphologically exhibited different rate of assimilation of amino acids. Amino acids in mixtures were utilized better than when supplied singly. Although different species had their own preference to certain amino acids yet there was a simultaneous utilization of both good and poor amino acids.     

Studies on the fungi associated with tomato fruit rots and effects of environment on storage

Seven fungi associated with fruit rot of tomato were isolated includingFusarium equiseti, F. chlamydosporum, Alternaria solani, Geotrichum candidum, Acremonium recifei, Aspergillus flavus andA. niger. They were all pathogenic on tomato fruits, most pathogenic beingGeotrichum candidum followed byA. niger. Least rot was caused byAlternaria solani. The optimum temperature for maximum rotting caused byG. candidum, A. niger andA. flavus was 30°C. The relative humidity for maximum rot ranged from 70–90%. Tomato fruits stored well at 0–10°C and rather poorly at 20–30°C. Fruits stored at 35°C showed blemishes. The best RH for storage ranged between 60 and 90%.     

Factors affecting entomopathogenic nematode infection ofPlutella xylostella on a leaf surface

We investigated the ability of entomopathogenic nematodes to infect diamondback moth (DBM),Plutella xylostella (L.) (Lepidoptera: Plutellidae) on a leaf surface. In a leaf disk assay, mortality of late stage DBM larvae ranged from <7% caused bySteinernema kushidai Mamiya to >95% caused byS. carpocapsae (Weiser) All strain. LC₅₀ values forS. carpocapsae, S. riobravis Cabanillas, Poinar & Raulston, andHeterorhabditis bacteriophora Poinar NC1 strain were 14.6, 15.4, and 65.4 nematodes/larva, respectively.S. carpocapsae, S. riobravis, andH. bacteriophora caused 29%, 33%, and 14% mortality of DBM pupae, respectively. DBM mortality caused byS. carpocapsae on radish declined at low (<76%) to moderate (76–90%) RH, because nematode survival and infectivity declined at low (<76%) to moderate (76–90%) RH. However, DBM mortality caused byS. riobravis did not decline with RH.S. riobravis survival declined with RH, but infectivity did not. Overall, nematode survival and infectivity to DBM larvae were lower forS. riobravis than forS. carpocapsae. In addition, DBM mortality was higher on radish plants (pubescent leaves) than on cabbage plants (glaborous leaves).     

Contribution of the mesophilic fungi of different spices in Egypt

Thirty-eight genera and 81 species of fungi were isolated and identified from 120 samples of 24 kinds of spices collected from different places at Assiut Governorate, Egypt. Predominant genera wereAspergillus (25 species) andPenicillium (7 species) of whichA. flavus, A. niger, A. ochraceus, A. fumigatus, A. flavus var.columnaris, A. terreus, P. chrysogenum andP. corylophilum were the most commonly occurring.     

Fungi associated with dried fish in Sri Lanka

The mycoflora of dried-salted fish from markets in Kandy, Sri Lanka was studied with emphasis on visibly spoiled dried fish. A total of 61 fungal isolates from 25 dried-fish were isolated and identified. The most prevalent fungus wasAspergillus niger. Species ofAspergillus flavus, A. fumigatus, A. glaucus, A. restrictus, Aureobasidium spp.Basipetospora halophila (a genuinely halophilic fungus)Cladosporium herbarum, Gliomastix, spp.,Penicillium chalybeum andPenicillium expansum were present. The isolated fungi did not grow in synthetic media containing more than 30% sodium chloride.Aureobasidium spp. andGliomastix spp. did not grow on dried-fish under laboratory conditions. The protective exoskeleton appeared to prevent fungal growth on dried shrimp. TheA. flavus strains isolated were not aflatoxigenic.     

Feeding behavior ofEuseius stipulatus andTyphlodromus phialatus on the citrus red mitePanonychus citri [Acari: Phytoseiidae,Tetranychidae]

Observations were made on the feeding behavior of the two main phytoseiid species in Spanish Citrus orchards,Euseius stipulatus (Athias-Henriot) andTyphlodromus phialatus Athias-henriot. The experiences were carried out by rearing the predatory mites on excised orange leaves, and always with an excess of the prey the Citrus Red Mite (=CRM)Panonychus citri (McGregor). In experiments with all stages of CRM, the number of prey killed per hour was 5.12 and 2.00, the percentage of successful attacks, 58% and 21%, and the mean time spent feeding on each prey was 5.1 and 12.2 minutes for starving females ofE. stipulatus andT. phialatus respectively.E. stipulatus feeds on all stages of the prey except eggs, andT. philatus, on all stages, except males. Both species attack much less successfully females ofP. citri rather than immatures. In experiments with adult females and eggs ofP. citri as prey, the mean number of prey killed daily was 4.51 females forE. stipulatus, and 2.01 females and 2.12 eggs forT. philatus. Considering this killing rate and the number of eggs laid by the predators in the same period, it can be concluded thatE. stipulatus consumes only 30% of the content of the preys killed, whereasT. philatus consumes a percentage of prey variable between individuals and ranging from 40% to 100%. These differences in feeding behavior between the two species could partly explain differences in their efficiency as biocontrol agents ofP. citri observed in the field.      

Studies on mycoflora of salt marshes in Egypt. IV=osmophilic fungi

Ninety-five species and seven varieties which belong to thirty-nine genera were isolated from 74 soil samples from salt marshes. At 28°C, on 30% sucrose Czapek's agar, ninety species and four varieties which belong to thirty-six genera were encountered, from which A. niger, A. fumigatus A. terreus and P. notatum were the most frequent. On 60% sucrose Czapek's agar, sixty-three species and three varieties were recovered which belong to twenty-five genera, from which A. niger, A. fumigatus, Cladosporium herbarum and A. terreus were the most frequent.At 45°C, on 30% sucrose, sixteen species and four varieties were identified, but on 60% sucrose, fourteen species and three varieties were isolated. A. fumigatus and A. niger were the most frequent on both sucrose concentrations.The results reveal that the soil samples poor in total osmophilic fungi (at 28°C) were significantly higher in their content of total soluble salts, Na and K and significantly lower in the average number of species per soil samples than the rich ones; the difference was nonsignificant in case of organic matter.     

Peanut-pod mycoflora and kernel infection

Summary The mycoflora in soil clinging to dry pods of peanuts of the Spanish variety Argentine was sampled in 2 experiments by serially washing pods for increasing periods in changes of sterile water. Of the 9 principal fungi found,Aspergillus niger, A. flavus, A. terreus, Rhizopus spp. andSclerotium bataticola were present initially in relatively small numbers and decreased rapidly in subsequent dilutions. This decrease paralleled a decrease in weight of suspended material and in percentage of soil and organic particles greater than 0.016 mm in size.Penicillium funiculosum, P. rubrum, P. citrinum, andFusarium spp. were found in large numbers and increased or slowly decreased in numbers in subsequent dilutions. In some instances variations in numbers followed trends of percentages of soil and organic particles less than 0.016 mm in size.When dry pods with this known mycoflora were allowed to hydrate over a 6-day period at 26°, 32°, or 38°C, there was extensive pod penetration and kernel infection byA. niger, A. flavus, S. bataticola andRhizopus spp. but not by other fungi. The degree ofA. flavus andA. niger infection increased with increasing temperatures.Approved by the Director as Journal Series Paper No. 135.     

Root surface area measurements based on adsorption and desorption of nitrite

A method, based on the negative adsorption of NO₂ ^-, has been developed to determine surface area of roots. Young roots of 3–4 year old plants ofAcacia catechu, Eucalyptus camaldulensis andLeucaena leucocephala were up-rooted and cut into 18 cylindrical pieces. Each root piece was immersed individually for 10 sec in 0.05M, 0.10M and 0.15M aqueous NaNO₂ solution and the excess solution on the root surface allowed to drain off. It was then transferred to conical flask containing distilled water and shaken for 15 min for desorption of nitrite. A known quantity of this aliquot was reacted with 1% acidic sulphanilamide and 0.02% NED HCl. A pink colour developed, and its optical density was read at 540 nm. A positive linear correlation was noted between colour density and root surface area. The respective correlation coefficientvalues for 0.05M, 0.10M and 0.15M NaNO₂ solutions were 0.973, 0.963 and 0.964 forAcacia catechu, 0.933, 0.903 and 0.898 forEucalyptus camaldulensis and 0.968, 0.976 and 0.972 forLeucaena leucocephala (significant atp<0.001). The method was successfully adopted to determine the root surface area of seedlings ofAlbizia lebbek, A. procera, Acacia auriculiformis, A. nilotica, Dalbergia latifolia andD. sissoo.     

Bacterial and fungal metabolites of rhizospheric microflora of cotton antagonistic to Rhizoctonia solani Kühn

Summary Growth response ofRhizoctonia solani Kühn, the damping-off fungus, to metabolites of selected antagonistic rhizospheric bacteria and fungi of some Egyptian cotton varieties, namely, two strains ofBacillus subtilis Cohn,Aspergillus terreus Thom, andAspergillus flavus Link produced in culture media containing nitrate- or ammonium-nitrogen sources, proved the potency ofB. subtilis metabolites in inhibitingR. solani mycelial growth whether from nitrate- or ammonium-nitrogen culture media. Metabolite filtrates ofB. subtilis (II) are more potent than those ofB. subtilis (I). Increasing concentration of bacterial metabolite filtrates resulted in a decreased mycelial dry weight ofR. solani. The bacterial inhibitory factor forR. solani mycelial growth is partially affected by heat. Metabolite filtrates ofA. terreus from nitrate-nitrogen are slightly more potent than from ammonium-nitrogen culture media while an opposite relation is evident withA. flavus metabolites. Growth responses ofR. solani to different experimental dilutions of metabolite filtrates ofA. terreus andA. flavus proved the intervention of the nutritive factor in witholding growth of the damping-off fungus.     

Expression and secretion of barley α-amylase and A.niger glucoamylase in Saccharomyces cerevisiae

cDNAs of barley α-amylase andA. niger glucoamylase were cloned in oneE. coli-yeast shuttle plasmid resulting in the construction of expression secretion vector pMAG15. pMAG15 was transformed intoS. cerevisiae GRF18 by protoplast transformation. The barley α-amylase andA. niger glucoamylase were efficiently expressed under the control of promoter and terminator of yeast PGK gene and their own signal sequence. Over 99% of the enzyme activity expressed was secreted to the medium. The recombinant yeast strain, S.cerevisiae GRF18 (pMAG15), hydrolyzes 99% of the starch in YPS medium containing 15% starch in 47 h. The glucose produced can be used for the production of ethanol. Project supported by the Guangdong Natural Science Foundation.     

Pectinolytic enzymes associated with the soft rots ofCitrus sinensis caused byAspergillus aculeatus andBotryodiplodia theobromae

Botryodiplodia theobromae andAspergillus aculeatus causing soft rots ofCitrus fruits were grown on wheat offal medium. The filtered washings of the wheat offal cultures were then assayed and found to contain pectinmethylesterases (PME) and polygalacturonases (PG). The two pectinases were also detected in large quantities from the filtrates of rotted fruits ofCitrus sinensis incited by each of the two test fungi. Two enzyme filtrates, one from rotted fruits ofCitrus sinensis and the other made up of pectinases from fungal cultures were introduced onto sterilised degreened fruits. Each of the two filtrates induced rot symptoms similar to those incited by the test fungi.Aspergillus aculeatus produced less PME and more PG thanBotryodiplodia theobromae.     

Studies on the fungus flora of three grains in Egypt

In wheat, corn and sorghum grains twenty-six genera and seventy-seven species including sixteen ofAspergillus and twenty-one ofPenicillium were identified.In grain samples adjusted to various moisture levels (up to 18.8 % on a dry-weight basis) and stored for 4 months at 8, 20 and 30 C seed-borne fungi were monthly identified and counted, and the germinability of the grains was tested. In the control samples (moisture content 7.1–8.2 %) temperature had no effect on the fungal counts and on the precentage germination. With the rise of temperature and moisture content the fungal counts markedly increased and the germinability declined.The list of fungi dominant in one or more of the experiments, included eight species ofAspergillus, six ofPenicillium, two ofFusarium and one each ofAlternaria andCurvularia. The order of dominance of these fungi varied according to the type of grain, the length of storage and the treatment.A. niger was the dominant organism in the control samples of the three grains. It could grow successfully at high moisture contents but above 15 %, it was usually overgrown by other fungi. In wheatP. citrinum andA. sydowii, in cornP. citrinum andA. terreus, and in sorghumA. terreus andA. niger were the dominant fungi at moisture contents above 15 % after four months storage at 30 C. When stored at 8 CPenicillium species tended to predominate over other fungi in grains with high moisture contents.In surface-sterilized grains adjusted to 15 % moisture content, inoculated with six dominant fungi separately and incubated at 30 C,A. niger, P. citrinum andP. variabile caused severe deterioration in the three grains;A. ochraceus in wheat only andF. moniliforme in wheat and corn;C. spicifer was slightly injurious to the three grains.     

Chromosomal location of 45S rDNA and dfr gene in Citrus sinensis

Dihydroflavonol 4-reductase (DFR) is a key enzyme in the anthocyanin biosynthesis. In this study, the localization of 45S rDNA and dfr gene (named as CsDFR-bo) of the blood orange (Citrus sinensis Osbeck cv. Ruby) on chromosomes was investigated by fluorescence in situ hybridization (FISH). A karyotype of C. sinensis was reconstructed based on the length of mitotic metaphase chromosomes. The 45S rDNAs were localized on chromosomes 2p and 7q. The detection ratios of 45S rDNA in the two chromosomes were 69.5 and 77.3 %, respectively. The CsDFR-bo was proved to be a single-copy gene and localized on chromosome 3p. The detection ratio of CsDFR-bo was 8.2 %.