Indoor airbornePenicillium species in Taiwan

Penicillium species, well-known indoor airborne fungi, are considered to be important causative agents of extrinsic bronchial asthma. For selecting the proper species for clinical investigations, it is important to know which are found indoors. In the present study, 176 plates of modified Mehrlich's Medium were exposed for 20 min in living rooms and bedrooms of 88 homes in Taipei, Taiwan. A total of 5897 colonies of fungi were isolated, varying from one to 329 per house. Of the total, 910 colonies (15.4%) were identified asPenicillium spp. The three most frequently encountered species wereP. citrinum, P. crustosum andP. implicatum. Penicillium citrinum accounted for 40.5% (369 from 28 houses);P. implicatum, for 5.2% (47 from three houses); andP. crustosum, for 2.1% (19 from seven houses).Penicillium citrinum was judged to be the most prevalent airborne fungus in Taiwan. The allergenic significance of this mold is under further investigation.     

Microflora of raw cacao beans

Whole non-moldy cacao beans from 14 sources cultured on Czapek's agar with six percent NaCl yielded species ofAspergillus glaucus group,Mucor pusillus and unidentified yeast and bacteria. The average number of bacterial colonies from the 14 sources of non-moldy cacao beans was 32.7 million per gram. The average number of colonies of filamentous fungi in dilution cultures was 57,000 colonies per gram. Yeast colonies were present in the amount of 15.8 million colonies per gram. The moldy beans analyzed contained fungi and bacterial counts in the billions; also, yeast was not isolated from the moldy samples.Paper Number 3170 of the Journal Series of the North Carolina State University Agricultural Experiment Station, Raleigh, North Carolina 27607.     

The effect of three species of mites upon fungal growth on wheat

Every week, for 20 weeks, the growth of naturally occurring grain storage fungi on wheat infested with the three commonest British grain storage mites,Acarus siro, Glycyphagus destructor andTyrophagus longior, was compared with that on uninfested wheat.The number of colonies of theAspergillus glaucus group per gram were always less on grain infested with mites than on uninfested grain.Penicillium spp. were also less numerous on grain which was infested withA. siro but did not appear to be affected by the other mites. In contrast, two fungi which are pathogenic to mites,Aspergillus restrictus andWallemia sebi, were more abundant in the presence of certain mites. The former was associated withG. destructor, the latter withG. destructor andA. siro.The three species of mites either feed on theA. glaucus group andPenicillium spp., or inhibit them by an unknown secretion. Pathogenic fungi are probably avoided. Mites are therefore an important variable in studies on fungal growth during grain drying and storage.     

Sampling dust from human dwellings to estimate the prevalence ofDermatophagoides mite and cat allergens

Summary Quantification of specific allergens in household dust samples may provide important information for selecting appropriate allergen control methods, and monitoring efficacy and compliance. The purpose of this study was to investigate the source of variation in mite and cat allergen measurements associated with dust sample collection. Discrete and composite dust samples were collected on a filter using a special vacuum sampling device. Aqueous extracts of the dust samples were prepared thenDer p I,Der f I, andFel d I were quantitated by enzyme immunoassays (EIA). Mite and cat allergens were frequently detected in dust samples from human dwellings, and the amounts of these allergens varied significantly (p<0.01) among dwellings. The differences of allergen measurements among duplicate samples taken immediately and up to three weeks later appear to be much smaller than differences among houses and between rooms. Variation among dust samples taken from living rooms and bedrooms of the same dwelling suggest differences in allergen reservoirs. Composite samples formed by sampling specific objects within a room may provide a reliable estimate of allergen exposure in that room. Dust samples from discrete objects are useful to find and monitor specific reservoirs of mite and cat allergens.     

A method for the selective isolation ofMyxococcus directly from soil

A new method is described for the selective isolation of species ofMyxococcus directly from soil by dilution plating. The method involves suppression of competing microorganisms with antibiotics combined with air drying and wet heat treatment of soils. Fungi were eliminated by supplementing the plating medium with cycloheximide and nystatin. Non-sporulating bacteria were controlled by air drying soils and then heating aqueous soil dilutions for 10 min at 56°C. The predominant sporulating bacteria in soil,Streptomyces andBacillus, were suppressed by adding either tiacumicin B, ristocetin or vancomycin to the medium. Swarming ofMyxococcus colonies was controlled with a casein digest-yeast extract plating medium (CY-C10 agar). Ultrasound treatment of soil suspensions gave the highest number ofMyxococcus colonies in the soils studied, but these cultures could be recovered without ultrasound. Strains ofMyxococccus fulvus, M. xanthus, M. coralloides, M. stipitatus andM. virescens were isolated from soil using this technique. Soils examined yielded one or twoMyxococcus species per sample.     

The occurrence of keratinophilic fungi in queensland

Summary Keratinophilic fungi have been isolated and identified in soil samples from 233 sites in Queensland and 12 from the Northern Territory. Total numbers of the fungi isolated are given, together with their occurrence in various broad types of locality.It is noted that populated localities produced a higher incidence of keratinophilic fungi than remote areas. Exceptions to this were found in beach sand, 17 samples of which produced only two growths ofChrysosporium species and no potentially pathogenic fungi.Culture technique, and the method of examination of colonies are discussed, and the morphological features of several of the more commonly occurring species are described.Isolates ofChrysosporium tropicum were made from two samples, one from Alice Springs and one from Brisbane. This is the first time this fungus has been reported in Australia.     

Isolation and characterization of microsatellite loci in Bemisia tabaci (Hemiptera: Aleyrodidae)

Microsatellite‐enriched genomic libraries were obtained from the whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) using a magnetic/biotin capture of repetitive sequences. Ten dinucleotide markers were successfully isolated and characterized from these libraries. Variability was assessed in six populations of B. tabaci collected from different localities of the island of Crete, Greece. The number of alleles per locus in approximately 105 individuals screened across populations ranged from two to 13. Averaged observed heterozygosity over the six populations ranged from 0.001 to 0.58.     

Mycoecology of willow and cottonwood lowland communities in Southern Wisconsin I. Soil microfungi in the willow-cottonwood forests

Summary A survey of the soil microfungi in 5Salix nigra-Populus deltoides forests in southern Wisconsin was conducted. The dilution plate method was employed to obtain 500 isolates per stand. The species present and their frequencies of occurrence were determined. The dominant forms,Trichoderma viride, Cladosporium cladosporioides, Gliocladium roseum, Mucor hiemalis, Coniothyrium sp. 5154,Mortierella minutissima, andPenicillium thomii, accounted for 41 % of the 2,500 isolates but only 4.5 % of the 154 species. They were followed at a second level of prevalence byPenicillium janthinellum P. multicolor, Mortierella alpina, andPhoma sp. 5157. The distribution of these taxa and others in the willow-cottonwood community was found to be correlated with an organic matter gradient. The Dematiaceae and the Sphaerioidaceae characterized populations obtained from the dry pioneer sites; the Mucorales and Moniliaceae became increasingly abundant as the percentage of organic matter increased. The number of fungal propagules ranged from 3,000 to 234,000 per gram of dry soil, the highest numbers occurring in soils with greater organic matter. The willow-cottonwood microfungal population was most similar to one obtained from soils of the closely related southern Wisconsin wet-mesic forests and least similar to ones isolated from the northern Wisconsin bogs and spruce-tamarack swamps.     

Sensitivity of Rhizobia to vanillin

The sensitivity of Rhizobia isolated from pea, fenugreek, gram, cowpea, urid andRhizobium meliloti, Rhizobium trifolii andRhizobium japonicum was studied in asparagine-mannitol, salt-mannitol and salt media. It was observed that Rhizobia from gram were most resistant.Rhizobium japonicum was found to be resistant up to 50 mg vanillin/100 ml. Vanillin-resistant strains could utilize vanillin as the sole carbon source. In the case of pea, gram and fenugreek vanillin was found to be utilized in the presence of mannitol.     

Extent and effect of Black Band Disease on a Caribbean reef

The effect of Black Band Disease (BBD) among colonies ofMontastrea annularis, M. cavernosa, Diploria strigosa, D. labryinthiformis, S. siderea andColpophyllia natans was determined at 7 shallow locations in the Virgin Islands. Between September 1988 and November 1988, 0.2% of 9204 colonies of these species were infected with BBD in 6908 m² of reef at 22 randomly chosen areas. Infected colonies were not clumped suggesting that the disease is not highly infectious between colonies. BBD infection rates in areas surveyed 4 times between August 1988 and September 1989 in Greater Lameshur Bay, St. John, USVI, were significantly lower in winter compared to summer. BBDs were found on 5.5% of the colonies ofD. strigosa in Fall 1988, and 7 out of 12 infected colonies lost >75% of their tissue in 6 months. Low level, chronic BBD infections could convert 3.9% of the living cover ofD.strigosa to free space per year, thereby creating substrata for successional processes.     

Field evaluations of disposable sticky lures for surveillance of Aedes aegypti (Stegomyia aegypti) and Culex quinquefasciatus in Jakarta

From December 1997 to April 1998, disposable sticky lures (1608 lure days) were trialled in homes in north Jakarta, Indonesia as surveillance tools for Aedes aegypti (Stegomyia aegypti) (Diptera: Culicidae) and Culex quinquefasciatus (Diptera: Culicidae), referenced to indoor resting adult collections (92 × 10 min). The lures collected 89.4% of the total of 1339 Ae. aegypti and 92.1% of the total of 1272 Cx. quinquefasciatus collected by all methods. Because there were no significant differences with respect to numbers collected in bedrooms, living rooms and kitchens, bedrooms were selected for subsequent trials for reasons of convenience. The main trials involved a replicated complete block design with L‐lysine and sodium carbonate. Lures without attractant or with four different dilutions of L‐lysine collected 3.4–8.5 times more Ae. aegypti and 4.2–8.1 times more Cx. quinquefasciatus than were collected by mouth aspirator. Lures with or without dilutions of sodium carbonate collected 2.7–5.0 times more Ae. aegypti and 1.8–4.2 times more Cx. quinquefasciatus than aspirator collections. The precision associated with catches of sticky lures was better than that for aspirator collections. Although olfactants generally improved the numbers of mosquitoes collected, the differences in catch between lures with and without attractants were usually non‐significant. Any deficit in catch may be offset by increasing the surveillance period to ≥30 days to detect all four dengue serotypes from infected mosquitoes.     

Keratinophilic fungi in the antarctic environment

Results of a study on the diffusion of keratinophilic fungi in an Antarctic environment are given. Nine soil samples collected from as many sites along the coast of Ross Sea, and six dust samples inside the Italian scientific base were examined by direct inoculation and hair baiting methods for soil samples and plate dilution method for dust samples. As regards the variety of species isolated and the counting of the numbers of colonies, plate dilution method proved to be very effective.Aspergillus spp.,Cladosporium sp., Dematiaceae,Fusarium sp.,Geomyces pannorum v.pannorum, G. pannorum v.vinaceus, Mycelia sterilia,Penicillium spp. were isolated from soil. From the dust the following moulds were isolated:Aphanoascus fulvescens, Aspergillus sp.,Beauveria sp.,Chrysosporium carmichaelii, Dematiaceae, Geomyces pannorum v.pannorum, G. pannorum v.vinaceus, Malbranchea gypsea, Mycelia sterilia, Nectria inventa, Penicillium spp.,Scopulariopsis brevicaulis, Scopulariopsis sp. andTrichophyton mentagrophytes. The presence of four colonies ofTrichophyton mentagrophytes is emphasized and correlated with the anthropization process.     

Effect of inoculum density,nitrogen source and saprophytic fungi on Fusarium wilt of Mexican lime

Summary Mexican lime seedlings were inoculated with 0, 500, 1000, 2000, 4000 and 8000 microconidia ofFusarium oxysporum f. sp.citri per gram of potting media. The percent infection and mean disease severity rating increased with increasing inoculum density of the pathogen. In potting mix infested withAspergillus ochraceus, Penicillium funiculosum andTrichoderma harzianum at 5000 conidia per gram 2 weeks prior to infestation withF. oxysporum f. sp.citri at 0, 1000, 4000, and 8000 microconidia per gram,A. ochraceus reduced,P. funiculosum increased andT. harzianum had no effect on disease severity or pathogen population. OnlyP. funiculosum showed antagonistic activityin vitro against the pathogen. Disease severity and pathogen propagule densitites were greater and pH was lower in potting media fertilized with NH₄–N than in media fertilized with NO₃–N.Portion of M. S. thesis submitted by the senior author to the Graduate School, University of Florida, Gainesville. Florida Agricultural Experiment Stations Journal Series No. 4221.     

Nonsymbiotic nitrogen-fixing micro-organisms in forest and tundra soils

Summary Soil samples obtained from various forested sites in North Carolina and Washington and from Alaskan tundra were examined for the presence of heterotrophic, nonsymbiotic nitrogen-fixing micro-organisms. Aerobic, nitrogen-fixing micro-organisms were not isolated from any of the soils examined. Estimates of anaerobic nitrogen-fixing bacteria in these soils ranged from 50,000 to 2,000,000/g when a dilution plate technique and a medium supplemented with potato extract was used. However, the isolation of individual colonies from the dilution plates showed that many of these bacteria were unable to fix nitrogen. Soil populations well below 100,000/g were generally indicated by this colony isolation technique. Differentiation of the colonies by size improved the accuracy of the dilution plate estimates somewhat. Dilution tube procedures appeared more suitable for obtaining accurate counts of nitrogen-fixing anaerobes in the soil than the use of dilution plates. The predominant nitrogen-fixing bacterium in most soils was a facultative anaerobe,Bacillus polymyxa. Appreciable numbers of nitrogen-fixing clostridia were also found in several tree nursery soils but were seldom isolated from forest and tundra samples. The clostridia isolated were classified asClostridium butyricum andC. pasteurianum. Variations in the fermentation patterns of these bacteria occurred when the nitrogen supply of the medium was altered. TheC. butyricum isolates were all from forest soils while all except one of theC. pasteuranium isolates were from tundra soils. Paper number2998 of the Journal Series of the North Carolina State University Agricultural Experiment Station, Raleigh, N.C     

A test of the model of the economic defendability of a resource and territoriality using youngEtroplus maculatus andPelmatochromis subocellatus kribensis

YoungEtroplus maculatus andPelmatochromis subocellatus kribensis were reared on diets of low, medium, or high quantities of food and the ontogeny of behavior documented until fish matured. Data were categorized into: (1) from the beginning of the experiment to the midpoint (100 days forE. maculatus and 118 days forP. s. kribensis); and (2) from the midpoint to maturity. For both species the tendency to be territorial, as deduced by the numbers of territories defended, or number of charges or rams performed, was explained by a unimodal relationship between territorial tendency and food available per gram of fish. Young fish receiving low quantities of food were highly territorial, but as they grew and food available per gram of fish decreased, they gave up territorial behavior. Young fish receiving high quantities of food were not territorial initially, but as they grew became increasingly territorial. Fish receiving intermediate quantities of food always defended territories. Lateral displays were performed most often by fish receiving intermediate quantities of food apparently because they were ambivalent being close to either the lower or upper thresholds for territoriality.     

The Selection of an Isolate of the Hyphomycete Fungus,Metarhizium anisopliae,for Control of Termites in Australia

Ninety-three isolates ofMetarhizium anisopliae,mostly derived from a survey of termite material, were screened for activity againstNasutitermes exitiosusandCoptotermes frenchiorC. acinaciformisusing a grooming assay technique. Twenty-six of the most promising isolates were further evaluated by bioassay againstN. exitiosusandC. acinaciformis.All isolates were pathogenic withCoptotermesspp. being more susceptible thanN. exitiosus.A group of nine isolates, chosen for their level of pathogenicity for one or other genus of termites and to represent a genetically diverse group, was finally compared in a minicolony test using termite colonies in 1 liter jars. The isolate, code-named FI-610 (derived from nest-mound material ofC. lacteusin SE New South Wales), was one of the most effective isolates against termites from both of the two colonies tested. This isolate also grew relatively well on agar plates at 36°C. FI-610 was thus selected for field trials and was found to be effective in killing colonies ofC. acinaciformiswhen 10 g (=3 × 10¹¹conidia) or more of conidial powder was blown into the center of the large mound colonies.     

Staining method of poly(3-hydroxyalkanoic acids) producing bacteria by nile blue

Summary Using an ethanol solution of nile blue, we have developed an efficient method to detect the colonies of poly(3-hydroxyalkanoic acids) (PHA) producing bacteria on the agar plate. When the bacterial colonies with PHA granules were stained with nile blue, the stained colonies fluoresced bright orange on the irradiation of UV light. In the fluoresce emission spectra, fluorescence intensity increased with an increase in the PHA content of bacterial cells.Alcaligenes eutrophus andA.latus colonies with poly(3-hydroxybutyric acid) (PHB) homopolymer exhibited an emission maximum at 580nm on the excitation at 490nm. On the other hand,Pseudomonas oleovorans andP.putida with medium-chain-length (mcl-) PHA copolymers of C6, C8 and C10 units exhibited an emission maximum at 570nm.     

Fungal utilization of organophosphate pesticides and their degradation byAspergillus flavus andA. sydowii in soil

Fungal species were isolated which utilize organophosphate pesticides,viz. phosphorothioic (pirimiphos-methyl and pyrazophos), phosphorodithioic (dimethoate and malathion), phosphonic (lancer) and phosphoric (profenfos) acid derivatives. Pesticide degradation was studiedin vitro andin vivo (soil).Aspergillus flavus, A. fumigatus, A. niger, A. sydowii, A. terreus, Emericella nidulans, Fusarium oxysporum andPenicillium chrysogenum were isolated from pesticide-treated wheat straw. The number ofA. sydowii colonies was significantly promoted by 1 mmol/L pirimiphos-methyl, pyrazophos, lancer, dimethoate and malathion when used as phosphorus sources and by pirimiphos-methyl and pyrazophos when used as carbon sources. The number ofA. flavus colonies increased with 0.5 mmol/L lancer and malathion used as the only carbon sources.A. sydowii, A. niger, A. flavus, E. nidulans andF. oxysporum grew on, and utilized, 5 pesticides as phosphorus source and showed more than 50% mass growth.A. sydowii, A. flavus andF. oxysporum phosphatase hydrolyzed the pesticides suggesting that these species are important pesticide degraders.A. sydowii produced higher amounts of the phosphatase thanA. flavus andF. oxysporum. The enzyme was highly active against pyrazophos, lancer and malathion used as the only sources of organic phosphate.A. flavus andA. sydowii phosphatases efficiently hydrolyzed pesticides at 300 ppm in soil, the degradation at 1000 ppm was lower. Mineralization of 1000 ppm pesticides in soil amended with wheat straw was higher than in nonamended soil. All added pesticides except profenfos were degraded within 3 weeks. Lyophilized adapted biomass ofA. flavus andA. sydowii could thus be used for field biodegradation of these pesticides.     

Effect of the flavonoid quercetin on culture and isolation ofFrankia fromCasuarina root nodules

The growth of threeFrankia strains (HFPCcl3, ORS021001, ORS020607), isolated from nodules ofCasuarina, was unaffected by 5–15 μmol/L quercetin. Re-isolation ofFrankia strain HFPCc13 fromCasuarina root nodules was carried out with the addition of 15 μmol/L quercetin to three different media. The flavonoid significantly reduced fungal contaminants in the isolation plates and increased the number ofFrankia colonies per plate compared to controls without the flavonoid.     

Complete separation along matrilines in a social spider metapopulation inferred from hypervariable mitochondrial DNA region

The distribution and quantity of genetic diversity may be profoundly influenced by the emergence and dynamics of social groups. Permanent social living in spiders has resulted in the subdivision of their populations in more or less isolated colony lineages that grow, proliferate and become extinct without mixing with one another. A newly discovered hypervariable mitochondrial DNA region allowed us to examine the fine scale metapopulation structure in the social Anelosimus eximius. We sampled 39 colonies in Ecuador and French Guiana and identified 25 haplotypes. The majority of colonies contained one haplotype. Additional haplotypes occurred in approximately 15% of the colonies, and were always closely related to the common colony haplotype. Our findings confirm that colonies consist of single matrilines, with within‐colony variation explained by mutations within the matriline. We thus found no evidence of mixing of matrilines. Likewise, colonies in a cluster often shared a haplotype, implying common colony ancestry. In few cases, however, haplotypes were shared between more distant colonies, providing evidence for occasional longer distance dispersal and/or widespread colony lineages. The geographical localities of colonies were incongruent with phylogenetic trees and haplotype networks, showing that some areas contained two or more matrilines. Hence, females do not migrate into foreign colonies, but faithfully remain within their own colony lineage, even when they disperse into new areas. These results indicate that the fine scale metapopulation structure of pure matrilines is maintained over the long term and that colony turnover is not extensive or radical enough to homogenize entire geographical areas. Genetic diversity is thus preserved to some extent at the metapopulation level.